document new config options

* connection-track ICMP and ICMPv6 traffic

* icmpv6 only has identifier on echo

.github/ISSUE_TEMPLATE/config.yml

@@ -17,5 +17,5 @@ contact_links:
     about: 'The documentation is the best place to start if you are new to Nebula.'
 
   - name: 💁 Support/Chat
-    url: https://join.slack.com/t/nebulaoss/shared_invite/zt-2xqe6e7vn-k_KGi8s13nsr7cvHVvHvuQ
+    url: https://join.slack.com/t/nebulaoss/shared_invite/zt-39pk4xopc-CUKlGcb5Z39dQ0cK1v7ehA
     about: 'For faster support, join us on Slack for assistance!'

.github/workflows/gofmt.yml

@@ -14,11 +14,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Install goimports

.github/workflows/release.yml

@@ -10,11 +10,11 @@ jobs:
     name: Build Linux/BSD All
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -24,7 +24,7 @@ jobs:
           mv build/*.tar.gz release
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: linux-latest
           path: release
@@ -33,11 +33,11 @@ jobs:
     name: Build Windows
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Build
@@ -55,7 +55,7 @@ jobs:
           mv dist\windows\wintun build\dist\windows\
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: windows-latest
           path: build
@@ -66,16 +66,16 @@ jobs:
       HAS_SIGNING_CREDS: ${{ secrets.AC_USERNAME != '' }}
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
-      - uses: actions/setup-go@v5
+      - uses: actions/setup-go@v6
         with:
-          go-version: '1.24'
+          go-version: '1.25'
           check-latest: true
 
       - name: Import certificates
         if: env.HAS_SIGNING_CREDS == 'true'
-        uses: Apple-Actions/import-codesign-certs@v5
+        uses: Apple-Actions/import-codesign-certs@v6
         with:
           p12-file-base64: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_P12_BASE64 }}
           p12-password: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_PASSWORD }}
@@ -104,7 +104,7 @@ jobs:
           fi
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: darwin-latest
           path: ./release/*
@@ -124,11 +124,11 @@ jobs:
       # be overwritten
       - name: Checkout code
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Download artifacts
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v7
         with:
           name: linux-latest
           path: artifacts
@@ -160,10 +160,10 @@ jobs:
     needs: [build-linux, build-darwin, build-windows]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v7
         with:
           path: artifacts
 

.github/workflows/smoke-extra.yml

@@ -20,16 +20,19 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version-file: 'go.mod'
+        go-version: '1.25'
         check-latest: true
 
     - name: add hashicorp source
       run: wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor | sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg && echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
 
+    - name: workaround AMD-V issue  # https://github.com/cri-o/packaging/pull/306
+      run: sudo rmmod kvm_amd
+
     - name: install vagrant
       run: sudo apt-get update && sudo apt-get install -y vagrant virtualbox
 

.github/workflows/smoke.yml

@@ -18,11 +18,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: build

.github/workflows/smoke/smoke.sh

@@ -37,17 +37,18 @@ docker run --name host4 --device /dev/net/tun:/dev/net/tun --cap-add NET_ADMIN -
 sleep 1
 
 # grab tcpdump pcaps for debugging
-docker exec lighthouse1 tcpdump -i nebula1 -q -w - -U 2>logs/lighthouse1.inside.log >logs/lighthouse1.inside.pcap &
+docker exec lighthouse1 tcpdump -i tun0 -q -w - -U 2>logs/lighthouse1.inside.log >logs/lighthouse1.inside.pcap &
 docker exec lighthouse1 tcpdump -i eth0 -q -w - -U 2>logs/lighthouse1.outside.log >logs/lighthouse1.outside.pcap &
-docker exec host2 tcpdump -i nebula1 -q -w - -U 2>logs/host2.inside.log >logs/host2.inside.pcap &
+docker exec host2 tcpdump -i tun0 -q -w - -U 2>logs/host2.inside.log >logs/host2.inside.pcap &
 docker exec host2 tcpdump -i eth0 -q -w - -U 2>logs/host2.outside.log >logs/host2.outside.pcap &
-docker exec host3 tcpdump -i nebula1 -q -w - -U 2>logs/host3.inside.log >logs/host3.inside.pcap &
+docker exec host3 tcpdump -i tun0 -q -w - -U 2>logs/host3.inside.log >logs/host3.inside.pcap &
 docker exec host3 tcpdump -i eth0 -q -w - -U 2>logs/host3.outside.log >logs/host3.outside.pcap &
-docker exec host4 tcpdump -i nebula1 -q -w - -U 2>logs/host4.inside.log >logs/host4.inside.pcap &
+docker exec host4 tcpdump -i tun0 -q -w - -U 2>logs/host4.inside.log >logs/host4.inside.pcap &
 docker exec host4 tcpdump -i eth0 -q -w - -U 2>logs/host4.outside.log >logs/host4.outside.pcap &
 
 docker exec host2 ncat -nklv 0.0.0.0 2000 &
 docker exec host3 ncat -nklv 0.0.0.0 2000 &
+docker exec host4 ncat -nkluv 0.0.0.0 4000 &
 docker exec host2 ncat -e '/usr/bin/echo host2' -nkluv 0.0.0.0 3000 &
 docker exec host3 ncat -e '/usr/bin/echo host3' -nkluv 0.0.0.0 3000 &
 
@@ -119,11 +120,11 @@ echo
 echo " *** Testing conntrack"
 echo
 set -x
-# host2 can ping host3 now that host3 pinged it first
+
-docker exec host2 ping -c1 192.168.100.3
+# host2 speaking to host4 on UDP 4000 should allow it to reply, when firewall rules would normally not permit this
-# host4 can ping host2 once conntrack established
+docker exec host2 sh -c "/usr/bin/echo host2 | ncat -nuv 192.168.100.4 4000"
-docker exec host2 ping -c1 192.168.100.4
+docker exec host2 ncat -e '/usr/bin/echo helloagainfromhost2' -nkluv 0.0.0.0 4000 &
-docker exec host4 ping -c1 192.168.100.2
+docker exec host4 sh -c "/usr/bin/echo host4 | ncat -nuv 192.168.100.2 4000"
 
 docker exec host4 sh -c 'kill 1'
 docker exec host3 sh -c 'kill 1'

.github/workflows/test.yml

@@ -18,11 +18,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -32,9 +32,9 @@ jobs:
       run: make vet
 
     - name: golangci-lint
-      uses: golangci/golangci-lint-action@v7
+      uses: golangci/golangci-lint-action@v9
       with:
-        version: v2.0
+        version: v2.5
 
     - name: Test
       run: make test
@@ -45,7 +45,7 @@ jobs:
     - name: Build test mobile
       run: make build-test-mobile
 
-    - uses: actions/upload-artifact@v4
+    - uses: actions/upload-artifact@v6
       with:
         name: e2e packet flow linux-latest
         path: e2e/mermaid/linux-latest
@@ -56,11 +56,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -77,11 +77,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.22'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build
@@ -98,11 +98,11 @@ jobs:
         os: [windows-latest, macos-latest]
     steps:
 
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
-        go-version: '1.24'
+        go-version: '1.25'
         check-latest: true
 
     - name: Build nebula
@@ -115,9 +115,9 @@ jobs:
       run: make vet
 
     - name: golangci-lint
-      uses: golangci/golangci-lint-action@v7
+      uses: golangci/golangci-lint-action@v9
       with:
-        version: v2.0
+        version: v2.5
 
     - name: Test
       run: make test
@@ -125,7 +125,7 @@ jobs:
     - name: End 2 end
       run: make e2evv
 
-    - uses: actions/upload-artifact@v4
+    - uses: actions/upload-artifact@v6
       with:
         name: e2e packet flow ${{ matrix.os }}
         path: e2e/mermaid/${{ matrix.os }}

CHANGELOG.md

@@ -7,12 +7,129 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.10.3] - 2026-02-06
+
+### Security
+
+- Fix an issue where blocklist bypass is possible when using curve P256 since the signature can have 2 valid representations.
+  Both fingerprint representations will be tested against the blocklist.
+  Any newly issued P256 based certificates will have their signature clamped to the low-s form.
+  Nebula will assert the low-s signature form when validating certificates in a future version. [GHSA-69x3-g4r3-p962](https://github.com/slackhq/nebula/security/advisories/GHSA-69x3-g4r3-p962)
+
 ### Changed
 
-- `default_local_cidr_any` now defaults to false, meaning that any firewall rule
+- Improve error reporting if nebula fails to start due to a tun device naming issue. (#1588)
+
+## [1.10.2] - 2026-01-21
+
+### Fixed
+
+- Fix panic when using `use_system_route_table` that was introduced in v1.10.1. (#1580)
+
+### Changed
+
+- Fix some typos in comments. (#1582)
+- Dependency updates. (#1581)
+
+## [1.10.1] - 2026-01-16
+
+See the [v1.10.1](https://github.com/slackhq/nebula/milestone/26?closed=1) milestone for a complete list of changes.
+
+### Fixed
+
+- Fix a bug where an unsafe route derived from the system route table could be lost on a config reload. (#1573)
+- Fix the PEM banner for ECDSA P256 public keys. (#1552)
+- Fix a regression on Windows from 1.9.x where nebula could fall back to a less performant UDP listener if 
+  non-critical ioctls failed. (#1568)
+- Fix a bug in handshake processing when a peer sends an unexpected public key. (#1566)
+
+### Added
+
+- Add a config option to control accepting `recv_error` packets which defaults to `always`. (#1569)
+
+### Changed
+
+- Various dependency updates. (#1541, #1549, #1550, #1557, #1558, #1560, #1561, #1570, #1571)
+
+## [1.10.0] - 2025-12-04
+
+See the [v1.10.0](https://github.com/slackhq/nebula/milestone/16?closed=1) milestone for a complete list of changes.
+
+### Added
+
+- Support for ipv6 and multiple ipv4/6 addresses in the overlay.
+  A new v2 ASN.1 based certificate format.
+  Certificates now have a unified interface for external implementations.
+  (#1212, #1216, #1345, #1359, #1381, #1419, #1464, #1466, #1451, #1476, #1467, #1481, #1399, #1488, #1492, #1495, #1468, #1521, #1535, #1538)
+- Add the ability to mark packets on linux to better target nebula packets in iptables/nftables. (#1331)
+- Add ECMP support for `unsafe_routes`. (#1332)
+- PKCS11 support for P256 keys when built with `pkcs11` tag (#1153, #1482)
+
+### Changed
+
+- **NOTE**: `default_local_cidr_any` now defaults to false, meaning that any firewall rule
   intended to target an `unsafe_routes` entry must explicitly declare it via the
   `local_cidr` field. This is almost always the intended behavior. This flag is
-  deprecated and will be removed in a future release.
+  deprecated and will be removed in a future release. (#1373)
+- Improve logging when a relay is in use on an inbound packet. (#1533)
+- Avoid fatal errors if `rountines` is > 1 on systems that don't support more than 1 routine. (#1531)
+- Log a warning if a firewall rule contains an `any` that negates a more restrictive filter. (#1513)
+- Accept encrypted CA passphrase from an environment variable. (#1421)
+- Allow handshaking with any trusted remote. (#1509)
+- Log only the count of blocklisted certificate fingerprints instead of the entire list. (#1525)
+- Don't fatal when the ssh server is unable to be configured successfully. (#1520)
+- Update to build against go v1.25. (#1483)
+- Allow projects using `nebula` as a library with userspace networking to configure the `logger` and build version. (#1239) 
+- Upgrade to `yaml.v3`. (#1148, #1371, #1438, #1478)
+
+### Fixed
+
+- Fix a potential bug with udp ipv4 only on darwin. (#1532)
+- Improve lost packet statistics. (#1441, #1537)
+- Honor `remote_allow_list` in hole punch response. (#1186)
+- Fix a panic when `tun.use_system_route_table` is `true` and a route lacks a destination. (#1437) 
+- Fix an issue when `tun.use_system_route_table: true` could result in heavy CPU utilization when many thousands of routes
+  are present. (#1326) 
+- Fix tests for 32 bit machines. (#1394)
+- Fix a possible 32bit integer underflow in config handling. (#1353)
+- Fix moving a udp address from one vpn address to another in the `static_host_map`
+  which could cause rapid re-handshaking with an incorrect remote. (#1259)
+- Improve smoke tests in environments where the docker network is not the default. (#1347)
+
+## [1.9.7] - 2025-10-10
+
+### Security
+
+- Fix an issue where Nebula could incorrectly accept and process a packet from an erroneous source IP when the sender's
+  certificate is configured with unsafe_routes (cert v1/v2) or multiple IPs (cert v2). (#1494)
+
+### Changed
+
+- Disable sending `recv_error` messages when a packet is received outside the allowable counter window. (#1459)
+- Improve error messages and remove some unnecessary fatal conditions in the Windows and generic udp listener. (#1453)
+
+## [1.9.6] - 2025-7-15
+
+### Added
+
+- Support dropping inactive tunnels. This is disabled by default in this release but can be enabled with `tunnels.drop_inactive`. See example config for more details. (#1413)
+
+### Fixed
+
+- Fix Darwin freeze due to presence of some Network Extensions (#1426)
+- Ensure the same relay tunnel is always used when multiple relay tunnels are present (#1422)
+- Fix Windows freeze due to ICMP error handling (#1412)
+- Fix relay migration panic (#1403)
+
+## [1.9.5] - 2024-12-05
+
+### Added
+
+- Gracefully ignore v2 certificates. (#1282)
+
+### Fixed
+
+- Fix relays that refuse to re-establish after one of the remote tunnel pairs breaks. (#1277)
 
 ## [1.9.4] - 2024-09-09
 
@@ -671,7 +788,14 @@ created.)
 
 - Initial public release.
 
-[Unreleased]: https://github.com/slackhq/nebula/compare/v1.9.4...HEAD
+[Unreleased]: https://github.com/slackhq/nebula/compare/v1.10.3...HEAD
+[1.10.3]: https://github.com/slackhq/nebula/releases/tag/v1.10.3
+[1.10.2]: https://github.com/slackhq/nebula/releases/tag/v1.10.2
+[1.10.1]: https://github.com/slackhq/nebula/releases/tag/v1.10.1
+[1.10.0]: https://github.com/slackhq/nebula/releases/tag/v1.10.0
+[1.9.7]: https://github.com/slackhq/nebula/releases/tag/v1.9.7
+[1.9.6]: https://github.com/slackhq/nebula/releases/tag/v1.9.6
+[1.9.5]: https://github.com/slackhq/nebula/releases/tag/v1.9.5
 [1.9.4]: https://github.com/slackhq/nebula/releases/tag/v1.9.4
 [1.9.3]: https://github.com/slackhq/nebula/releases/tag/v1.9.3
 [1.9.2]: https://github.com/slackhq/nebula/releases/tag/v1.9.2

README.md

@@ -12,7 +12,7 @@ Further documentation can be found [here](https://nebula.defined.net/docs/).
 
 You can read more about Nebula [here](https://medium.com/p/884110a5579).
 
-You can also join the NebulaOSS Slack group [here](https://join.slack.com/t/nebulaoss/shared_invite/zt-2xqe6e7vn-k_KGi8s13nsr7cvHVvHvuQ).
+You can also join the NebulaOSS Slack group [here](https://join.slack.com/t/nebulaoss/shared_invite/zt-39pk4xopc-CUKlGcb5Z39dQ0cK1v7ehA).
 
 ## Supported Platforms
 

bits.go

@@ -9,14 +9,13 @@ type Bits struct {
 	length             uint64
 	current            uint64
 	bits               []bool
-	firstSeen          bool
 	lostCounter        metrics.Counter
 	dupeCounter        metrics.Counter
 	outOfWindowCounter metrics.Counter
 }
 
 func NewBits(bits uint64) *Bits {
-	return &Bits{
+	b := &Bits{
 		length:             bits,
 		bits:               make([]bool, bits, bits),
 		current:            0,
@@ -24,34 +23,37 @@ func NewBits(bits uint64) *Bits {
 		dupeCounter:        metrics.GetOrRegisterCounter("network.packets.duplicate", nil),
 		outOfWindowCounter: metrics.GetOrRegisterCounter("network.packets.out_of_window", nil),
 	}
+
+	// There is no counter value 0, mark it to avoid counting a lost packet later.
+	b.bits[0] = true
+	b.current = 0
+	return b
 }
 
-func (b *Bits) Check(l logrus.FieldLogger, i uint64) bool {
+func (b *Bits) Check(l *logrus.Logger, i uint64) bool {
 	// If i is the next number, return true.
-	if i > b.current || (i == 0 && b.firstSeen == false && b.current < b.length) {
+	if i > b.current {
 		return true
 	}
 
-	// If i is within the window, check if it's been set already. The first window will fail this check
+	// If i is within the window, check if it's been set already.
-	if i > b.current-b.length {
+	if i > b.current-b.length || i < b.length && b.current < b.length {
-		return !b.bits[i%b.length]
-	}
-
-	// If i is within the first window
-	if i < b.length {
 		return !b.bits[i%b.length]
 	}
 
 	// Not within the window
-	l.Debugf("rejected a packet (top) %d %d\n", b.current, i)
+	if l.Level >= logrus.DebugLevel {
+		l.Debugf("rejected a packet (top) %d %d\n", b.current, i)
+	}
 	return false
 }
 
 func (b *Bits) Update(l *logrus.Logger, i uint64) bool {
 	// If i is the next number, return true and update current.
 	if i == b.current+1 {
-		// Report missed packets, we can only understand what was missed after the first window has been gone through
+		// Check if the oldest bit was lost since we are shifting the window by 1 and occupying it with this counter
-		if i > b.length && b.bits[i%b.length] == false {
+		// The very first window can only be tracked as lost once we are on the 2nd window or greater
+		if b.bits[i%b.length] == false && i > b.length {
 			b.lostCounter.Inc(1)
 		}
 		b.bits[i%b.length] = true
@@ -59,61 +61,32 @@ func (b *Bits) Update(l *logrus.Logger, i uint64) bool {
 		return true
 	}
 
-	// If i packet is greater than current but less than the maximum length of our bitmap,
+	// If i is a jump, adjust the window, record lost, update current, and return true
-	// flip everything in between to false and move ahead.
+	if i > b.current {
-	if i > b.current && i < b.current+b.length {
+		lost := int64(0)
-		// In between current and i need to be zero'd to allow those packets to come in later
+		// Zero out the bits between the current and the new counter value, limited by the window size,
-		for n := b.current + 1; n < i; n++ {
+		// since the window is shifting
+		for n := b.current + 1; n <= min(i, b.current+b.length); n++ {
+			if b.bits[n%b.length] == false && n > b.length {
+				lost++
+			}
 			b.bits[n%b.length] = false
 		}
 
-		b.bits[i%b.length] = true
+		// Only record any skipped packets as a result of the window moving further than the window length
-		b.current = i
+		// Any loss within the new window will be accounted for in future calls
-		//l.Debugf("missed %d packets between %d and %d\n", i-b.current, i, b.current)
+		lost += max(0, int64(i-b.current-b.length))
-		return true
-	}
-
-	// If i is greater than the delta between current and the total length of our bitmap,
-	// just flip everything in the map and move ahead.
-	if i >= b.current+b.length {
-		// The current window loss will be accounted for later, only record the jump as loss up until then
-		lost := maxInt64(0, int64(i-b.current-b.length))
-		//TODO: explain this
-		if b.current == 0 {
-			lost++
-		}
-
-		for n := range b.bits {
-			// Don't want to count the first window as a loss
-			//TODO: this is likely wrong, we are wanting to track only the bit slots that we aren't going to track anymore and this is marking everything as missed
-			//if b.bits[n] == false {
-			//	lost++
-			//}
-			b.bits[n] = false
-		}
-
 		b.lostCounter.Inc(lost)
 
-		if l.Level >= logrus.DebugLevel {
-			l.WithField("receiveWindow", m{"accepted": true, "currentCounter": b.current, "incomingCounter": i, "reason": "window shifting"}).
-				Debug("Receive window")
-		}
 		b.bits[i%b.length] = true
 		b.current = i
 		return true
 	}
 
-	// Allow for the 0 packet to come in within the first window
+	// If i is within the current window but below the current counter,
-	if i == 0 && b.firstSeen == false && b.current < b.length {
+	// Check to see if it's a duplicate
-		b.firstSeen = true
+	if i > b.current-b.length || i < b.length && b.current < b.length {
-		b.bits[i%b.length] = true
+		if b.current == i || b.bits[i%b.length] == true {
-		return true
-	}
-
-	// If i is within the window of current minus length (the total pat window size),
-	// allow it and flip to true but to NOT change current. We also have to account for the first window
-	if ((b.current >= b.length && i > b.current-b.length) || (b.current < b.length && i < b.length)) && i <= b.current {
-		if b.current == i {
 			if l.Level >= logrus.DebugLevel {
 				l.WithField("receiveWindow", m{"accepted": false, "currentCounter": b.current, "incomingCounter": i, "reason": "duplicate"}).
 					Debug("Receive window")
@@ -122,18 +95,8 @@ func (b *Bits) Update(l *logrus.Logger, i uint64) bool {
 			return false
 		}
 
-		if b.bits[i%b.length] == true {
-			if l.Level >= logrus.DebugLevel {
-				l.WithField("receiveWindow", m{"accepted": false, "currentCounter": b.current, "incomingCounter": i, "reason": "old duplicate"}).
-					Debug("Receive window")
-			}
-			b.dupeCounter.Inc(1)
-			return false
-		}
-
 		b.bits[i%b.length] = true
 		return true
-
 	}
 
 	// In all other cases, fail and don't change current.
@@ -147,11 +110,3 @@ func (b *Bits) Update(l *logrus.Logger, i uint64) bool {
 	}
 	return false
 }
-
-func maxInt64(a, b int64) int64 {
-	if a > b {
-		return a
-	}
-
-	return b
-}

bits_test.go

@@ -15,48 +15,41 @@ func TestBits(t *testing.T) {
 	assert.Len(t, b.bits, 10)
 
 	// This is initialized to zero - receive one. This should work.
-
 	assert.True(t, b.Check(l, 1))
-	u := b.Update(l, 1)
+	assert.True(t, b.Update(l, 1))
-	assert.True(t, u)
 	assert.EqualValues(t, 1, b.current)
-	g := []bool{false, true, false, false, false, false, false, false, false, false}
+	g := []bool{true, true, false, false, false, false, false, false, false, false}
 	assert.Equal(t, g, b.bits)
 
 	// Receive two
 	assert.True(t, b.Check(l, 2))
-	u = b.Update(l, 2)
+	assert.True(t, b.Update(l, 2))
-	assert.True(t, u)
 	assert.EqualValues(t, 2, b.current)
-	g = []bool{false, true, true, false, false, false, false, false, false, false}
+	g = []bool{true, true, true, false, false, false, false, false, false, false}
 	assert.Equal(t, g, b.bits)
 
 	// Receive two again - it will fail
 	assert.False(t, b.Check(l, 2))
-	u = b.Update(l, 2)
+	assert.False(t, b.Update(l, 2))
-	assert.False(t, u)
 	assert.EqualValues(t, 2, b.current)
 
 	// Jump ahead to 15, which should clear everything and set the 6th element
 	assert.True(t, b.Check(l, 15))
-	u = b.Update(l, 15)
+	assert.True(t, b.Update(l, 15))
-	assert.True(t, u)
 	assert.EqualValues(t, 15, b.current)
 	g = []bool{false, false, false, false, false, true, false, false, false, false}
 	assert.Equal(t, g, b.bits)
 
 	// Mark 14, which is allowed because it is in the window
 	assert.True(t, b.Check(l, 14))
-	u = b.Update(l, 14)
+	assert.True(t, b.Update(l, 14))
-	assert.True(t, u)
 	assert.EqualValues(t, 15, b.current)
 	g = []bool{false, false, false, false, true, true, false, false, false, false}
 	assert.Equal(t, g, b.bits)
 
 	// Mark 5, which is not allowed because it is not in the window
 	assert.False(t, b.Check(l, 5))
-	u = b.Update(l, 5)
+	assert.False(t, b.Update(l, 5))
-	assert.False(t, u)
 	assert.EqualValues(t, 15, b.current)
 	g = []bool{false, false, false, false, true, true, false, false, false, false}
 	assert.Equal(t, g, b.bits)
@@ -69,10 +62,29 @@ func TestBits(t *testing.T) {
 
 	// Walk through a few windows in order
 	b = NewBits(10)
-	for i := uint64(0); i <= 100; i++ {
+	for i := uint64(1); i <= 100; i++ {
 		assert.True(t, b.Check(l, i), "Error while checking %v", i)
 		assert.True(t, b.Update(l, i), "Error while updating %v", i)
 	}
+
+	assert.False(t, b.Check(l, 1), "Out of window check")
+}
+
+func TestBitsLargeJumps(t *testing.T) {
+	l := test.NewLogger()
+	b := NewBits(10)
+	b.lostCounter.Clear()
+
+	b = NewBits(10)
+	b.lostCounter.Clear()
+	assert.True(t, b.Update(l, 55)) // We saw packet 55 and can still track 45,46,47,48,49,50,51,52,53,54
+	assert.Equal(t, int64(45), b.lostCounter.Count())
+
+	assert.True(t, b.Update(l, 100)) // We saw packet 55 and 100 and can still track 90,91,92,93,94,95,96,97,98,99
+	assert.Equal(t, int64(89), b.lostCounter.Count())
+
+	assert.True(t, b.Update(l, 200)) // We saw packet 55, 100, and 200 and can still track 190,191,192,193,194,195,196,197,198,199
+	assert.Equal(t, int64(188), b.lostCounter.Count())
 }
 
 func TestBitsDupeCounter(t *testing.T) {
@@ -124,8 +136,7 @@ func TestBitsOutOfWindowCounter(t *testing.T) {
 	assert.False(t, b.Update(l, 0))
 	assert.Equal(t, int64(1), b.outOfWindowCounter.Count())
 
-	//tODO: make sure lostcounter doesn't increase in orderly increment
+	assert.Equal(t, int64(19), b.lostCounter.Count()) // packet 0 wasn't lost
-	assert.Equal(t, int64(20), b.lostCounter.Count())
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(1), b.outOfWindowCounter.Count())
 }
@@ -137,8 +148,6 @@ func TestBitsLostCounter(t *testing.T) {
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	//assert.True(t, b.Update(0))
-	assert.True(t, b.Update(l, 0))
 	assert.True(t, b.Update(l, 20))
 	assert.True(t, b.Update(l, 21))
 	assert.True(t, b.Update(l, 22))
@@ -149,7 +158,7 @@ func TestBitsLostCounter(t *testing.T) {
 	assert.True(t, b.Update(l, 27))
 	assert.True(t, b.Update(l, 28))
 	assert.True(t, b.Update(l, 29))
-	assert.Equal(t, int64(20), b.lostCounter.Count())
+	assert.Equal(t, int64(19), b.lostCounter.Count()) // packet 0 wasn't lost
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 
@@ -158,8 +167,6 @@ func TestBitsLostCounter(t *testing.T) {
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	assert.True(t, b.Update(l, 0))
-	assert.Equal(t, int64(0), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 9))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
 	// 10 will set 0 index, 0 was already set, no lost packets
@@ -214,6 +221,62 @@ func TestBitsLostCounter(t *testing.T) {
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 }
 
+func TestBitsLostCounterIssue1(t *testing.T) {
+	l := test.NewLogger()
+	b := NewBits(10)
+	b.lostCounter.Clear()
+	b.dupeCounter.Clear()
+	b.outOfWindowCounter.Clear()
+
+	assert.True(t, b.Update(l, 4))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 1))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 9))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 2))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 3))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 5))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 6))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 7))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	// assert.True(t, b.Update(l, 8))
+	assert.True(t, b.Update(l, 10))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 11))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+
+	assert.True(t, b.Update(l, 14))
+	assert.Equal(t, int64(0), b.lostCounter.Count())
+	// Issue seems to be here, we reset missing packet 8 to false here and don't increment the lost counter
+	assert.True(t, b.Update(l, 19))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 12))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 13))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 15))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 16))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 17))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 18))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 20))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 21))
+
+	// We missed packet 8 above
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.Equal(t, int64(0), b.dupeCounter.Count())
+	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
+}
+
 func BenchmarkBits(b *testing.B) {
 	z := NewBits(10)
 	for n := 0; n < b.N; n++ {

boring.go

@@ -1,5 +1,4 @@
 //go:build boringcrypto
-// +build boringcrypto
 
 package nebula
 

calculated_remote.go

@@ -84,16 +84,11 @@ func NewCalculatedRemotesFromConfig(c *config.C, k string) (*bart.Table[[]*calcu
 
 	calculatedRemotes := new(bart.Table[[]*calculatedRemote])
 
-	rawMap, ok := value.(map[any]any)
+	rawMap, ok := value.(map[string]any)
 	if !ok {
 		return nil, fmt.Errorf("config `%s` has invalid type: %T", k, value)
 	}
-	for rawKey, rawValue := range rawMap {
+	for rawCIDR, rawValue := range rawMap {
-		rawCIDR, ok := rawKey.(string)
-		if !ok {
-			return nil, fmt.Errorf("config `%s` has invalid key (type %T): %v", k, rawKey, rawKey)
-		}
-
 		cidr, err := netip.ParsePrefix(rawCIDR)
 		if err != nil {
 			return nil, fmt.Errorf("config `%s` has invalid CIDR: %s", k, rawCIDR)
@@ -129,7 +124,7 @@ func newCalculatedRemotesListFromConfig(cidr netip.Prefix, raw any) ([]*calculat
 }
 
 func newCalculatedRemotesEntryFromConfig(cidr netip.Prefix, raw any) (*calculatedRemote, error) {
-	rawMap, ok := raw.(map[any]any)
+	rawMap, ok := raw.(map[string]any)
 	if !ok {
 		return nil, fmt.Errorf("invalid type: %T", raw)
 	}

cert/ca_pool.go

@@ -141,10 +141,23 @@ func (ncp *CAPool) VerifyCertificate(now time.Time, c Certificate) (*CachedCerti
 		return nil, err
 	}
 
+	// Pre nebula v1.10.3 could generate signatures in either high or low s form and validation
+	// of signatures allowed for either. Nebula v1.10.3 and beyond clamps signature generation to low-s form
+	// but validation still allows for either. Since a change in the signature bytes affects the fingerprint, we
+	// need to test both forms until such a time comes that we enforce low-s form on signature validation.
+	fp2, err := CalculateAlternateFingerprint(c)
+	if err != nil {
+		return nil, fmt.Errorf("could not calculate alternate fingerprint to verify: %w", err)
+	}
+	if fp2 != "" && ncp.IsBlocklisted(fp2) {
+		return nil, ErrBlockListed
+	}
+
 	cc := CachedCertificate{
 		Certificate:       c,
 		InvertedGroups:    make(map[string]struct{}),
 		Fingerprint:       fp,
+		fingerprint2:      fp2,
 		signerFingerprint: signer.Fingerprint,
 	}
 
@@ -158,6 +171,11 @@ func (ncp *CAPool) VerifyCertificate(now time.Time, c Certificate) (*CachedCerti
 // VerifyCachedCertificate is the same as VerifyCertificate other than it operates on a pre-verified structure and
 // is a cheaper operation to perform as a result.
 func (ncp *CAPool) VerifyCachedCertificate(now time.Time, c *CachedCertificate) error {
+	// Check any available alternate fingerprint forms for this certificate, re P256 high-s/low-s
+	if c.fingerprint2 != "" && ncp.IsBlocklisted(c.fingerprint2) {
+		return ErrBlockListed
+	}
+
 	_, err := ncp.verify(c.Certificate, now, c.Fingerprint, c.signerFingerprint)
 	return err
 }

cert/ca_pool_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/slackhq/nebula/cert/p256"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -170,6 +171,15 @@ func TestCertificateV1_VerifyP256(t *testing.T) {
 	_, err = caPool.VerifyCertificate(time.Now(), c)
 	require.EqualError(t, err, "certificate is in the block list")
 
+	// Create a copy of the cert and swap to the alternate form for the signature
+	nc := c.Copy()
+	b, err := p256.Swap(c.Signature())
+	require.NoError(t, err)
+	require.NoError(t, nc.(*certificateV1).setSignature(b))
+
+	_, err = caPool.VerifyCertificate(time.Now(), nc)
+	require.EqualError(t, err, "certificate is in the block list")
+
 	caPool.ResetCertBlocklist()
 	_, err = caPool.VerifyCertificate(time.Now(), c)
 	require.NoError(t, err)
@@ -187,7 +197,7 @@ func TestCertificateV1_VerifyP256(t *testing.T) {
 	require.NoError(t, err)
 
 	caPool = NewCAPool()
-	b, err := caPool.AddCAFromPEM(caPem)
+	b, err = caPool.AddCAFromPEM(caPem)
 	require.NoError(t, err)
 	assert.Empty(t, b)
 
@@ -196,7 +206,17 @@ func TestCertificateV1_VerifyP256(t *testing.T) {
 	})
 
 	c, _, _, _ = NewTestCert(Version1, Curve_P256, ca, caKey, "test", time.Now(), time.Now().Add(5*time.Minute), nil, nil, []string{"test1"})
-	_, err = caPool.VerifyCertificate(time.Now(), c)
+	cc, err := caPool.VerifyCertificate(time.Now(), c)
+	require.NoError(t, err)
+
+	// Reset the blocklist and block the alternate form fingerprint
+	caPool.ResetCertBlocklist()
+	caPool.BlocklistFingerprint(cc.fingerprint2)
+	err = caPool.VerifyCachedCertificate(time.Now(), cc)
+	require.EqualError(t, err, "certificate is in the block list")
+
+	caPool.ResetCertBlocklist()
+	err = caPool.VerifyCachedCertificate(time.Now(), cc)
 	require.NoError(t, err)
 }
 
@@ -394,6 +414,15 @@ func TestCertificateV2_VerifyP256(t *testing.T) {
 	_, err = caPool.VerifyCertificate(time.Now(), c)
 	require.EqualError(t, err, "certificate is in the block list")
 
+	// Create a copy of the cert and swap to the alternate form for the signature
+	nc := c.Copy()
+	b, err := p256.Swap(c.Signature())
+	require.NoError(t, err)
+	require.NoError(t, nc.(*certificateV2).setSignature(b))
+
+	_, err = caPool.VerifyCertificate(time.Now(), nc)
+	require.EqualError(t, err, "certificate is in the block list")
+
 	caPool.ResetCertBlocklist()
 	_, err = caPool.VerifyCertificate(time.Now(), c)
 	require.NoError(t, err)
@@ -411,7 +440,7 @@ func TestCertificateV2_VerifyP256(t *testing.T) {
 	require.NoError(t, err)
 
 	caPool = NewCAPool()
-	b, err := caPool.AddCAFromPEM(caPem)
+	b, err = caPool.AddCAFromPEM(caPem)
 	require.NoError(t, err)
 	assert.Empty(t, b)
 
@@ -420,7 +449,17 @@ func TestCertificateV2_VerifyP256(t *testing.T) {
 	})
 
 	c, _, _, _ = NewTestCert(Version2, Curve_P256, ca, caKey, "test", time.Now(), time.Now().Add(5*time.Minute), nil, nil, []string{"test1"})
-	_, err = caPool.VerifyCertificate(time.Now(), c)
+	cc, err := caPool.VerifyCertificate(time.Now(), c)
+	require.NoError(t, err)
+
+	// Reset the blocklist and block the alternate form fingerprint
+	caPool.ResetCertBlocklist()
+	caPool.BlocklistFingerprint(cc.fingerprint2)
+	err = caPool.VerifyCachedCertificate(time.Now(), cc)
+	require.EqualError(t, err, "certificate is in the block list")
+
+	caPool.ResetCertBlocklist()
+	err = caPool.VerifyCachedCertificate(time.Now(), cc)
 	require.NoError(t, err)
 }
 

cert/cert.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"net/netip"
 	"time"
+
+	"github.com/slackhq/nebula/cert/p256"
 )
 
 type Version uint8
@@ -58,6 +60,9 @@ type Certificate interface {
 	// PublicKey is the raw bytes to be used in asymmetric cryptographic operations.
 	PublicKey() []byte
 
+	// MarshalPublicKeyPEM is the value of PublicKey marshalled to PEM
+	MarshalPublicKeyPEM() []byte
+
 	// Curve identifies which curve was used for the PublicKey and Signature.
 	Curve() Curve
 
@@ -107,6 +112,9 @@ type CachedCertificate struct {
 	InvertedGroups    map[string]struct{}
 	Fingerprint       string
 	signerFingerprint string
+
+	// A place to store a 2nd fingerprint if the certificate could have one, such as with P256
+	fingerprint2 string
 }
 
 func (cc *CachedCertificate) String() string {
@@ -116,6 +124,7 @@ func (cc *CachedCertificate) String() string {
 // Recombine will attempt to unmarshal a certificate received in a handshake.
 // Handshakes save space by placing the peers public key in a different part of the packet, we have to
 // reassemble the actual certificate structure with that in mind.
+// Implementations MUST assert the public key is not in the raw certificate bytes if the passed in public key is not empty.
 func Recombine(v Version, rawCertBytes, publicKey []byte, curve Curve) (Certificate, error) {
 	if publicKey == nil {
 		return nil, ErrNoPeerStaticKey
@@ -135,8 +144,7 @@ func Recombine(v Version, rawCertBytes, publicKey []byte, curve Curve) (Certific
 	case Version2:
 		c, err = unmarshalCertificateV2(rawCertBytes, publicKey, curve)
 	default:
-		//TODO: CERT-V2 make a static var
+		return nil, ErrUnknownVersion
-		return nil, fmt.Errorf("unknown certificate version %d", v)
 	}
 
 	if err != nil {
@@ -149,3 +157,31 @@ func Recombine(v Version, rawCertBytes, publicKey []byte, curve Curve) (Certific
 
 	return c, nil
 }
+
+// CalculateAlternateFingerprint calculates a 2nd fingerprint representation for P256 certificates
+// CAPool blocklist testing through `VerifyCertificate` and `VerifyCachedCertificate` automatically performs this step.
+func CalculateAlternateFingerprint(c Certificate) (string, error) {
+	if c.Curve() != Curve_P256 {
+		return "", nil
+	}
+
+	nc := c.Copy()
+	b, err := p256.Swap(nc.Signature())
+	if err != nil {
+		return "", err
+	}
+
+	switch v := nc.(type) {
+	case *certificateV1:
+		err = v.setSignature(b)
+	case *certificateV2:
+		err = v.setSignature(b)
+	default:
+		return "", ErrUnknownVersion
+	}
+
+	if err != nil {
+		return "", err
+	}
+	return nc.Fingerprint()
+}

cert/cert_v1.go

@@ -83,6 +83,10 @@ func (c *certificateV1) PublicKey() []byte {
 	return c.details.publicKey
 }
 
+func (c *certificateV1) MarshalPublicKeyPEM() []byte {
+	return marshalCertPublicKeyToPEM(c)
+}
+
 func (c *certificateV1) Signature() []byte {
 	return c.signature
 }
@@ -110,8 +114,10 @@ func (c *certificateV1) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:
@@ -420,7 +426,7 @@ func unmarshalCertificateV1(b []byte, publicKey []byte) (*certificateV1, error)
 			unsafeNetworks: make([]netip.Prefix, len(rc.Details.Subnets)/2),
 			notBefore:      time.Unix(rc.Details.NotBefore, 0),
 			notAfter:       time.Unix(rc.Details.NotAfter, 0),
-			publicKey:      make([]byte, len(rc.Details.PublicKey)),
+			publicKey:      nil,
 			isCA:           rc.Details.IsCA,
 			curve:          rc.Details.Curve,
 		},
@@ -431,12 +437,19 @@ func unmarshalCertificateV1(b []byte, publicKey []byte) (*certificateV1, error)
 	copy(nc.details.groups, rc.Details.Groups)
 	nc.details.issuer = hex.EncodeToString(rc.Details.Issuer)
 
+	// If a public key is passed in as an argument, the certificate pubkey must be empty
+	// and the passed-in pubkey copied into the cert.
 	if len(publicKey) > 0 {
-		nc.details.publicKey = publicKey
+		if len(rc.Details.PublicKey) != 0 {
+			return nil, ErrCertPubkeyPresent
+		}
+		nc.details.publicKey = make([]byte, len(publicKey))
+		copy(nc.details.publicKey, publicKey)
+	} else {
+		nc.details.publicKey = make([]byte, len(rc.Details.PublicKey))
+		copy(nc.details.publicKey, rc.Details.PublicKey)
 	}
 
-	copy(nc.details.publicKey, rc.Details.PublicKey)
-
 	var ip netip.Addr
 	for i, rawIp := range rc.Details.Ips {
 		if i%2 == 0 {

cert/cert_v1_test.go

@@ -1,6 +1,7 @@
 package cert
 
 import (
+	"crypto/ed25519"
 	"fmt"
 	"net/netip"
 	"testing"
@@ -13,6 +14,7 @@ import (
 )
 
 func TestCertificateV1_Marshal(t *testing.T) {
+	t.Parallel()
 	before := time.Now().Add(time.Second * -60).Round(time.Second)
 	after := time.Now().Add(time.Second * 60).Round(time.Second)
 	pubKey := []byte("1234567890abcedfghij1234567890ab")
@@ -60,6 +62,120 @@ func TestCertificateV1_Marshal(t *testing.T) {
 	assert.Equal(t, nc.Groups(), nc2.Groups())
 }
 
+func TestCertificateV1_Unmarshal(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := []byte("1234567890abcedfghij1234567890ab")
+	invalidPubkey := []byte("00000000000000000000000000000000")
+
+	nc := certificateV1{
+		details: detailsV1{
+			name: "testing",
+			networks: []netip.Prefix{
+				mustParsePrefixUnmapped("10.1.1.1/24"),
+				mustParsePrefixUnmapped("10.1.1.2/16"),
+			},
+			unsafeNetworks: []netip.Prefix{
+				mustParsePrefixUnmapped("9.1.1.2/24"),
+				mustParsePrefixUnmapped("9.1.1.3/16"),
+			},
+			groups:    []string{"test-group1", "test-group2", "test-group3"},
+			notBefore: before,
+			notAfter:  after,
+			publicKey: pubKey,
+			isCA:      false,
+			issuer:    "1234567890abcedfghij1234567890ab",
+		},
+		signature: []byte("1234567890abcedfghij1234567890ab"),
+	}
+
+	// This certificate has a pubkey included
+	certWithPubkey, err := nc.Marshal()
+	require.NoError(t, err)
+
+	// This certificate is missing the pubkey section
+	certWithoutPubkey, err := nc.MarshalForHandshakes()
+	require.NoError(t, err)
+
+	// Cert has no pubkey and no pubkey passed in must fail to validate
+	isNil, err := unmarshalCertificateV1(certWithoutPubkey, nil)
+	require.Error(t, err)
+
+	// Cert has different pubkey than one passed in must fail
+	isNil, err = unmarshalCertificateV1(certWithPubkey, invalidPubkey)
+	require.Nil(t, isNil)
+	require.Error(t, err)
+
+	// Cert has pubkey and no pubkey argument works ok
+	_, err = unmarshalCertificateV1(certWithPubkey, nil)
+	require.NoError(t, err)
+
+	// Cert has no pubkey and valid, correctly signed pubkey passed in
+	nc2, err := unmarshalCertificateV1(certWithoutPubkey, pubKey)
+	require.NoError(t, err)
+
+	assert.Equal(t, pubKey, nc2.PublicKey())
+}
+
+func TestCertificateV1_PublicKeyPem(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := ed25519.PublicKey("1234567890abcedfghij1234567890ab")
+
+	nc := certificateV1{
+		details: detailsV1{
+			name:           "testing",
+			networks:       []netip.Prefix{},
+			unsafeNetworks: []netip.Prefix{},
+			groups:         []string{"test-group1", "test-group2", "test-group3"},
+			notBefore:      before,
+			notAfter:       after,
+			publicKey:      pubKey,
+			isCA:           false,
+			issuer:         "1234567890abcedfghij1234567890ab",
+		},
+		signature: []byte("1234567890abcedfghij1234567890ab"),
+	}
+
+	assert.Equal(t, Version1, nc.Version())
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem := "-----BEGIN NEBULA X25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA X25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.False(t, nc.IsCA())
+
+	nc.details.isCA = true
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem = "-----BEGIN NEBULA ED25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA ED25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.True(t, nc.IsCA())
+
+	pubP256KeyPem := []byte(`-----BEGIN NEBULA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA P256 PUBLIC KEY-----
+`)
+
+	pubP256KeyPemCA := []byte(`-----BEGIN NEBULA ECDSA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA ECDSA P256 PUBLIC KEY-----
+`)
+	pubP256Key, _, _, err := UnmarshalPublicKeyFromPEM(pubP256KeyPem)
+	require.NoError(t, err)
+	nc.details.curve = Curve_P256
+	nc.details.publicKey = pubP256Key
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPemCA))
+	assert.True(t, nc.IsCA())
+
+	nc.details.isCA = false
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.False(t, nc.IsCA())
+}
+
 func TestCertificateV1_Expired(t *testing.T) {
 	nc := certificateV1{
 		details: detailsV1{

cert/cert_v2.go

@@ -114,6 +114,10 @@ func (c *certificateV2) PublicKey() []byte {
 	return c.publicKey
 }
 
+func (c *certificateV2) MarshalPublicKeyPEM() []byte {
+	return marshalCertPublicKeyToPEM(c)
+}
+
 func (c *certificateV2) Signature() []byte {
 	return c.signature
 }
@@ -149,8 +153,10 @@ func (c *certificateV2) CheckSignature(key []byte) bool {
 	case Curve_CURVE25519:
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
-		x, y := elliptic.Unmarshal(elliptic.P256(), key)
+		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)
-		pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
+		if err != nil {
+			return false
+		}
 		hashed := sha256.Sum256(b)
 		return ecdsa.VerifyASN1(pubKey, hashed[:], c.signature)
 	default:
@@ -433,11 +439,7 @@ func (c *certificateV2) validate() error {
 				if !hasV6Networks {
 					return NewErrInvalidCertificateProperties("IPv6 unsafe networks require an IPv6 address assignment: %s", network)
 				}
-			} else if network.Addr().Is4() {
+			} // as long as we have any IP address, IPv4 UnsafeNetworks are allowed
-				if !hasV4Networks {
-					return NewErrInvalidCertificateProperties("IPv4 unsafe networks require an IPv4 address assignment: %s", network)
-				}
-			}
 		}
 	}
 
@@ -586,7 +588,13 @@ func unmarshalCertificateV2(b []byte, publicKey []byte, curve Curve) (*certifica
 	// Maybe grab the public key
 	var rawPublicKey cryptobyte.String
 	if len(publicKey) > 0 {
-		rawPublicKey = publicKey
+		// If a public key is passed in, then the handshake certificate must
+		// not have a public key present
+		if input.PeekASN1Tag(TagCertPublicKey) {
+			return nil, ErrCertPubkeyPresent
+		}
+		rawPublicKey = make(cryptobyte.String, len(publicKey))
+		copy(rawPublicKey, publicKey)
 	} else if !input.ReadOptionalASN1(&rawPublicKey, nil, TagCertPublicKey) {
 		return nil, ErrBadFormat
 	}

cert/cert_v2_test.go

@@ -15,6 +15,7 @@ import (
 )
 
 func TestCertificateV2_Marshal(t *testing.T) {
+	t.Parallel()
 	before := time.Now().Add(time.Second * -60).Round(time.Second)
 	after := time.Now().Add(time.Second * 60).Round(time.Second)
 	pubKey := []byte("1234567890abcedfghij1234567890ab")
@@ -75,6 +76,117 @@ func TestCertificateV2_Marshal(t *testing.T) {
 	assert.Equal(t, nc.Groups(), nc2.Groups())
 }
 
+func TestCertificateV2_Unmarshal(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := []byte("1234567890abcedfghij1234567890ab")
+
+	nc := certificateV2{
+		details: detailsV2{
+			name: "testing",
+			networks: []netip.Prefix{
+				mustParsePrefixUnmapped("10.1.1.2/16"),
+				mustParsePrefixUnmapped("10.1.1.1/24"),
+			},
+			unsafeNetworks: []netip.Prefix{
+				mustParsePrefixUnmapped("9.1.1.3/16"),
+				mustParsePrefixUnmapped("9.1.1.2/24"),
+			},
+			groups:    []string{"test-group1", "test-group2", "test-group3"},
+			notBefore: before,
+			notAfter:  after,
+			isCA:      false,
+			issuer:    "1234567890abcdef1234567890abcdef",
+		},
+		signature: []byte("1234567890abcdef1234567890abcdef"),
+		publicKey: pubKey,
+	}
+
+	db, err := nc.details.Marshal()
+	require.NoError(t, err)
+	nc.rawDetails = db
+
+	certWithPubkey, err := nc.Marshal()
+	require.NoError(t, err)
+	//t.Log("Cert size:", len(b))
+	certWithoutPubkey, err := nc.MarshalForHandshakes()
+	require.NoError(t, err)
+
+	// Cert must not have a pubkey if one is passed in as an argument
+	_, err = unmarshalCertificateV2(certWithPubkey, pubKey, Curve_CURVE25519)
+	require.ErrorIs(t, err, ErrCertPubkeyPresent)
+
+	// Certs must have pubkeys
+	_, err = unmarshalCertificateV2(certWithoutPubkey, nil, Curve_CURVE25519)
+	require.ErrorIs(t, err, ErrBadFormat)
+
+	// Ensure proper unmarshal if a pubkey is passed in
+	nc2, err := unmarshalCertificateV2(certWithoutPubkey, pubKey, Curve_CURVE25519)
+	require.NoError(t, err)
+
+	assert.Equal(t, nc.PublicKey(), nc2.PublicKey())
+}
+
+func TestCertificateV2_PublicKeyPem(t *testing.T) {
+	t.Parallel()
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := ed25519.PublicKey("1234567890abcedfghij1234567890ab")
+
+	nc := certificateV2{
+		details: detailsV2{
+			name:           "testing",
+			networks:       []netip.Prefix{},
+			unsafeNetworks: []netip.Prefix{},
+			groups:         []string{"test-group1", "test-group2", "test-group3"},
+			notBefore:      before,
+			notAfter:       after,
+			isCA:           false,
+			issuer:         "1234567890abcedfghij1234567890ab",
+		},
+		publicKey: pubKey,
+		signature: []byte("1234567890abcedfghij1234567890ab"),
+	}
+
+	assert.Equal(t, Version2, nc.Version())
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem := "-----BEGIN NEBULA X25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA X25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.False(t, nc.IsCA())
+
+	nc.details.isCA = true
+	assert.Equal(t, Curve_CURVE25519, nc.Curve())
+	pubPem = "-----BEGIN NEBULA ED25519 PUBLIC KEY-----\nMTIzNDU2Nzg5MGFiY2VkZmdoaWoxMjM0NTY3ODkwYWI=\n-----END NEBULA ED25519 PUBLIC KEY-----\n"
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), pubPem)
+	assert.True(t, nc.IsCA())
+
+	pubP256KeyPem := []byte(`-----BEGIN NEBULA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA P256 PUBLIC KEY-----
+`)
+
+	pubP256KeyPemCA := []byte(`-----BEGIN NEBULA ECDSA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA ECDSA P256 PUBLIC KEY-----
+`)
+
+	pubP256Key, _, _, err := UnmarshalPublicKeyFromPEM(pubP256KeyPem)
+	require.NoError(t, err)
+	nc.curve = Curve_P256
+	nc.publicKey = pubP256Key
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPemCA))
+	assert.True(t, nc.IsCA())
+
+	nc.details.isCA = false
+	assert.Equal(t, Curve_P256, nc.Curve())
+	assert.Equal(t, string(nc.MarshalPublicKeyPEM()), string(pubP256KeyPem))
+	assert.False(t, nc.IsCA())
+}
+
 func TestCertificateV2_Expired(t *testing.T) {
 	nc := certificateV2{
 		details: detailsV2{

cert/crypto_test.go

@@ -79,7 +79,7 @@ qrlJ69wer3ZUHFXA
 	assert.Nil(t, k)
 	assert.Equal(t, rest, invalidPem)
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	curve, k, rest, err = DecryptAndUnmarshalSigningPrivateKey(passphrase, rest)
 	require.EqualError(t, err, "input did not contain a valid PEM encoded block")

cert/errors.go

@@ -20,6 +20,8 @@ var (
 	ErrPublicPrivateKeyMismatch   = errors.New("public key and private key are not a pair")
 	ErrPrivateKeyEncrypted        = errors.New("private key must be decrypted")
 	ErrCaNotFound                 = errors.New("could not find ca for the certificate")
+	ErrUnknownVersion             = errors.New("certificate version unrecognized")
+	ErrCertPubkeyPresent          = errors.New("certificate has unexpected pubkey present")
 
 	ErrInvalidPEMBlock                   = errors.New("input did not contain a valid PEM encoded block")
 	ErrInvalidPEMCertificateBanner       = errors.New("bytes did not contain a proper certificate banner")

cert/p256/p256.go

@@ -0,0 +1,122 @@
+package p256
+
+import (
+	"crypto/elliptic"
+	"errors"
+	"math/big"
+
+	"filippo.io/bigmod"
+
+	"golang.org/x/crypto/cryptobyte"
+	"golang.org/x/crypto/cryptobyte/asn1"
+)
+
+var halfN = new(big.Int).Rsh(elliptic.P256().Params().N, 1)
+var nMod *bigmod.Modulus
+
+func init() {
+	n, err := bigmod.NewModulus(elliptic.P256().Params().N.Bytes())
+	if err != nil {
+		panic(err)
+	}
+	nMod = n
+}
+
+func IsNormalized(sig []byte) (bool, error) {
+	r, s, err := parseSignature(sig)
+	if err != nil {
+		return false, err
+	}
+	return checkLowS(r, s), nil
+}
+
+func checkLowS(_, s []byte) bool {
+	bigS := new(big.Int).SetBytes(s)
+	// Check if S <= (N/2), because we want to include the midpoint in the set of low-s
+	return bigS.Cmp(halfN) <= 0
+}
+
+func swap(r, s []byte) ([]byte, []byte, error) {
+	var err error
+	bigS, err := bigmod.NewNat().SetBytes(s, nMod)
+	if err != nil {
+		return nil, nil, err
+	}
+	sNormalized := nMod.Nat().Sub(bigS, nMod)
+
+	return r, sNormalized.Bytes(nMod), nil
+}
+
+func Normalize(sig []byte) ([]byte, error) {
+	r, s, err := parseSignature(sig)
+	if err != nil {
+		return nil, err
+	}
+
+	if checkLowS(r, s) {
+		return sig, nil
+	}
+
+	newR, newS, err := swap(r, s)
+	if err != nil {
+		return nil, err
+	}
+
+	return encodeSignature(newR, newS)
+}
+
+// Swap will change sig between its current form to the opposite high or low form.
+func Swap(sig []byte) ([]byte, error) {
+	r, s, err := parseSignature(sig)
+	if err != nil {
+		return nil, err
+	}
+
+	newR, newS, err := swap(r, s)
+	if err != nil {
+		return nil, err
+	}
+
+	return encodeSignature(newR, newS)
+}
+
+// parseSignature taken exactly from crypto/ecdsa/ecdsa.go
+func parseSignature(sig []byte) (r, s []byte, err error) {
+	var inner cryptobyte.String
+	input := cryptobyte.String(sig)
+	if !input.ReadASN1(&inner, asn1.SEQUENCE) ||
+		!input.Empty() ||
+		!inner.ReadASN1Integer(&r) ||
+		!inner.ReadASN1Integer(&s) ||
+		!inner.Empty() {
+		return nil, nil, errors.New("invalid ASN.1")
+	}
+	return r, s, nil
+}
+
+func encodeSignature(r, s []byte) ([]byte, error) {
+	var b cryptobyte.Builder
+	b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
+		addASN1IntBytes(b, r)
+		addASN1IntBytes(b, s)
+	})
+	return b.Bytes()
+}
+
+// addASN1IntBytes encodes in ASN.1 a positive integer represented as
+// a big-endian byte slice with zero or more leading zeroes.
+func addASN1IntBytes(b *cryptobyte.Builder, bytes []byte) {
+	for len(bytes) > 0 && bytes[0] == 0 {
+		bytes = bytes[1:]
+	}
+	if len(bytes) == 0 {
+		b.SetError(errors.New("invalid integer"))
+		return
+	}
+	b.AddASN1(asn1.INTEGER, func(c *cryptobyte.Builder) {
+		if bytes[0]&0x80 != 0 {
+			c.AddUint8(0)
+		}
+		c.AddBytes(bytes)
+	})
+}

cert/p256/p256_test.go

@@ -0,0 +1,28 @@
+package p256
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFlipping(t *testing.T) {
+	priv, err1 := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err1)
+
+	out, err := ecdsa.SignASN1(rand.Reader, priv, []byte("big chungus"))
+	require.NoError(t, err)
+
+	r, s, err := parseSignature(out)
+	require.NoError(t, err)
+
+	r, s1, err := swap(r, s)
+	require.NoError(t, err)
+	r, s2, err := swap(r, s1)
+	require.NoError(t, err)
+	require.Equal(t, s, s2)
+	require.NotEqual(t, s, s1)
+}

cert/pem.go

@@ -7,19 +7,26 @@ import (
 	"golang.org/x/crypto/ed25519"
 )
 
-const (
+const ( //cert banners
-	CertificateBanner                = "NEBULA CERTIFICATE"
+	CertificateBanner   = "NEBULA CERTIFICATE"
-	CertificateV2Banner              = "NEBULA CERTIFICATE V2"
+	CertificateV2Banner = "NEBULA CERTIFICATE V2"
-	X25519PrivateKeyBanner           = "NEBULA X25519 PRIVATE KEY"
+)
-	X25519PublicKeyBanner            = "NEBULA X25519 PUBLIC KEY"
-	EncryptedEd25519PrivateKeyBanner = "NEBULA ED25519 ENCRYPTED PRIVATE KEY"
-	Ed25519PrivateKeyBanner          = "NEBULA ED25519 PRIVATE KEY"
-	Ed25519PublicKeyBanner           = "NEBULA ED25519 PUBLIC KEY"
 
-	P256PrivateKeyBanner               = "NEBULA P256 PRIVATE KEY"
+const ( //key-agreement-key banners
-	P256PublicKeyBanner                = "NEBULA P256 PUBLIC KEY"
+	X25519PrivateKeyBanner = "NEBULA X25519 PRIVATE KEY"
+	X25519PublicKeyBanner  = "NEBULA X25519 PUBLIC KEY"
+	P256PrivateKeyBanner   = "NEBULA P256 PRIVATE KEY"
+	P256PublicKeyBanner    = "NEBULA P256 PUBLIC KEY"
+)
+
+/* including "ECDSA" in the P256 banners is a clue that these keys should be used only for signing */
+const ( //signing key banners
 	EncryptedECDSAP256PrivateKeyBanner = "NEBULA ECDSA P256 ENCRYPTED PRIVATE KEY"
 	ECDSAP256PrivateKeyBanner          = "NEBULA ECDSA P256 PRIVATE KEY"
+	ECDSAP256PublicKeyBanner           = "NEBULA ECDSA P256 PUBLIC KEY"
+	EncryptedEd25519PrivateKeyBanner   = "NEBULA ED25519 ENCRYPTED PRIVATE KEY"
+	Ed25519PrivateKeyBanner            = "NEBULA ED25519 PRIVATE KEY"
+	Ed25519PublicKeyBanner             = "NEBULA ED25519 PUBLIC KEY"
 )
 
 // UnmarshalCertificateFromPEM will try to unmarshal the first pem block in a byte array, returning any non consumed
@@ -51,6 +58,16 @@ func UnmarshalCertificateFromPEM(b []byte) (Certificate, []byte, error) {
 
 }
 
+func marshalCertPublicKeyToPEM(c Certificate) []byte {
+	if c.IsCA() {
+		return MarshalSigningPublicKeyToPEM(c.Curve(), c.PublicKey())
+	} else {
+		return MarshalPublicKeyToPEM(c.Curve(), c.PublicKey())
+	}
+}
+
+// MarshalPublicKeyToPEM returns a PEM representation of a public key used for ECDH.
+// if your public key came from a certificate, prefer Certificate.PublicKeyPEM() if possible, to avoid mistakes!
 func MarshalPublicKeyToPEM(curve Curve, b []byte) []byte {
 	switch curve {
 	case Curve_CURVE25519:
@@ -62,6 +79,19 @@ func MarshalPublicKeyToPEM(curve Curve, b []byte) []byte {
 	}
 }
 
+// MarshalSigningPublicKeyToPEM returns a PEM representation of a public key used for signing.
+// if your public key came from a certificate, prefer Certificate.PublicKeyPEM() if possible, to avoid mistakes!
+func MarshalSigningPublicKeyToPEM(curve Curve, b []byte) []byte {
+	switch curve {
+	case Curve_CURVE25519:
+		return pem.EncodeToMemory(&pem.Block{Type: Ed25519PublicKeyBanner, Bytes: b})
+	case Curve_P256:
+		return pem.EncodeToMemory(&pem.Block{Type: ECDSAP256PublicKeyBanner, Bytes: b})
+	default:
+		return nil
+	}
+}
+
 func UnmarshalPublicKeyFromPEM(b []byte) ([]byte, []byte, Curve, error) {
 	k, r := pem.Decode(b)
 	if k == nil {
@@ -73,7 +103,7 @@ func UnmarshalPublicKeyFromPEM(b []byte) ([]byte, []byte, Curve, error) {
 	case X25519PublicKeyBanner, Ed25519PublicKeyBanner:
 		expectedLen = 32
 		curve = Curve_CURVE25519
-	case P256PublicKeyBanner:
+	case P256PublicKeyBanner, ECDSAP256PublicKeyBanner:
 		// Uncompressed
 		expectedLen = 65
 		curve = Curve_P256

cert/pem_test.go

@@ -44,7 +44,7 @@ bzBEr00kERQxxTzTsH8cpYEgRoipvmExvg8WP8NdAJEYJosB
 	assert.Equal(t, rest, invalidPem)
 	require.EqualError(t, err, "bytes did not contain a proper certificate banner")
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	cert, rest, err = UnmarshalCertificateFromPEM(rest)
 	assert.Nil(t, cert)
@@ -106,7 +106,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 	assert.Equal(t, rest, invalidPem)
 	require.EqualError(t, err, "bytes did not contain a proper Ed25519/ECDSA private key banner")
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	k, rest, curve, err = UnmarshalSigningPrivateKeyFromPEM(rest)
 	assert.Nil(t, k)
@@ -168,7 +168,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 	assert.Equal(t, rest, invalidPem)
 	require.EqualError(t, err, "bytes did not contain a proper private key banner")
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	k, rest, curve, err = UnmarshalPrivateKeyFromPEM(rest)
 	assert.Nil(t, k)
@@ -177,6 +177,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 }
 
 func TestUnmarshalPublicKeyFromPEM(t *testing.T) {
+	t.Parallel()
 	pubKey := []byte(`# A good key
 -----BEGIN NEBULA ED25519 PUBLIC KEY-----
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
@@ -220,7 +221,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 	require.EqualError(t, err, "bytes did not contain a proper public key banner")
 	assert.Equal(t, rest, invalidPem)
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
 	assert.Nil(t, k)
@@ -230,6 +231,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 }
 
 func TestUnmarshalX25519PublicKey(t *testing.T) {
+	t.Parallel()
 	pubKey := []byte(`# A good key
 -----BEGIN NEBULA X25519 PUBLIC KEY-----
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
@@ -240,6 +242,12 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAA=
 -----END NEBULA P256 PUBLIC KEY-----
+`)
+	oldPubP256Key := []byte(`# A good key
+-----BEGIN NEBULA ECDSA P256 PUBLIC KEY-----
+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+AAAAAAAAAAAAAAAAAAAAAAA=
+-----END NEBULA ECDSA P256 PUBLIC KEY-----
 `)
 	shortKey := []byte(`# A short key
 -----BEGIN NEBULA X25519 PUBLIC KEY-----
@@ -256,15 +264,22 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 -END NEBULA X25519 PUBLIC KEY-----`)
 
-	keyBundle := appendByteSlices(pubKey, pubP256Key, shortKey, invalidBanner, invalidPem)
+	keyBundle := appendByteSlices(pubKey, pubP256Key, oldPubP256Key, shortKey, invalidBanner, invalidPem)
 
 	// Success test case
 	k, rest, curve, err := UnmarshalPublicKeyFromPEM(keyBundle)
 	assert.Len(t, k, 32)
 	require.NoError(t, err)
-	assert.Equal(t, rest, appendByteSlices(pubP256Key, shortKey, invalidBanner, invalidPem))
+	assert.Equal(t, rest, appendByteSlices(pubP256Key, oldPubP256Key, shortKey, invalidBanner, invalidPem))
 	assert.Equal(t, Curve_CURVE25519, curve)
 
+	// Success test case
+	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
+	assert.Len(t, k, 65)
+	require.NoError(t, err)
+	assert.Equal(t, rest, appendByteSlices(oldPubP256Key, shortKey, invalidBanner, invalidPem))
+	assert.Equal(t, Curve_P256, curve)
+
 	// Success test case
 	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
 	assert.Len(t, k, 65)
@@ -284,7 +299,7 @@ AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
 	require.EqualError(t, err, "bytes did not contain a proper public key banner")
 	assert.Equal(t, rest, invalidPem)
 
-	// Fail due to ivalid PEM format, because
+	// Fail due to invalid PEM format, because
 	// it's missing the requisite pre-encapsulation boundary.
 	k, rest, curve, err = UnmarshalPublicKeyFromPEM(rest)
 	assert.Nil(t, k)

cert/sign.go

@@ -7,9 +7,10 @@ import (
 	"crypto/rand"
 	"crypto/sha256"
 	"fmt"
-	"math/big"
 	"net/netip"
 	"time"
+
+	"github.com/slackhq/nebula/cert/p256"
 )
 
 // TBSCertificate represents a certificate intended to be signed.
@@ -55,15 +56,10 @@ func (t *TBSCertificate) Sign(signer Certificate, curve Curve, key []byte) (Cert
 		}
 		return t.SignWith(signer, curve, sp)
 	case Curve_P256:
-		pk := &ecdsa.PrivateKey{
+		pk, err := ecdsa.ParseRawPrivateKey(elliptic.P256(), key)
-			PublicKey: ecdsa.PublicKey{
+		if err != nil {
-				Curve: elliptic.P256(),
+			return nil, err
-			},
-			// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L95
-			D: new(big.Int).SetBytes(key),
 		}
-		// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L119
-		pk.X, pk.Y = pk.Curve.ScalarBaseMult(key)
 		sp := func(certBytes []byte) ([]byte, error) {
 			// We need to hash first for ECDSA
 			// - https://pkg.go.dev/crypto/ecdsa#SignASN1
@@ -132,6 +128,13 @@ func (t *TBSCertificate) SignWith(signer Certificate, curve Curve, sp SignerLamb
 		return nil, err
 	}
 
+	if curve == Curve_P256 {
+		sig, err = p256.Normalize(sig)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	err = c.setSignature(sig)
 	if err != nil {
 		return nil, err

cert/sign_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/slackhq/nebula/cert/p256"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -89,3 +90,48 @@ func TestCertificateV1_SignP256(t *testing.T) {
 	require.NoError(t, err)
 	assert.NotNil(t, uc)
 }
+
+func TestCertificate_SignP256_AlwaysNormalized(t *testing.T) {
+	before := time.Now().Add(time.Second * -60).Round(time.Second)
+	after := time.Now().Add(time.Second * 60).Round(time.Second)
+	pubKey := []byte("01234567890abcedfghij1234567890ab1234567890abcedfghij1234567890ab")
+
+	tbs := TBSCertificate{
+		Version: Version1,
+		Name:    "testing",
+		Networks: []netip.Prefix{
+			mustParsePrefixUnmapped("10.1.1.1/24"),
+			mustParsePrefixUnmapped("10.1.1.2/16"),
+		},
+		UnsafeNetworks: []netip.Prefix{
+			mustParsePrefixUnmapped("9.1.1.2/24"),
+			mustParsePrefixUnmapped("9.1.1.3/16"),
+		},
+		Groups:    []string{"test-group1", "test-group2", "test-group3"},
+		NotBefore: before,
+		NotAfter:  after,
+		PublicKey: pubKey,
+		IsCA:      true,
+		Curve:     Curve_P256,
+	}
+
+	priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	require.NoError(t, err)
+	pub := elliptic.Marshal(elliptic.P256(), priv.PublicKey.X, priv.PublicKey.Y)
+	rawPriv := priv.D.FillBytes(make([]byte, 32))
+
+	for i := 0; i < 1000; i++ {
+		if i&1 == 1 {
+			tbs.Version = Version1
+		} else {
+			tbs.Version = Version2
+		}
+		c, err := tbs.Sign(nil, Curve_P256, rawPriv)
+		require.NoError(t, err)
+		assert.NotNil(t, c)
+		assert.True(t, c.CheckSignature(pub))
+		normie, err := p256.IsNormalized(c.Signature())
+		require.NoError(t, err)
+		assert.True(t, normie)
+	}
+}

cert_test/cert.go

@@ -114,6 +114,33 @@ func NewTestCert(v cert.Version, curve cert.Curve, ca cert.Certificate, key []by
 	return c, pub, cert.MarshalPrivateKeyToPEM(curve, priv), pem
 }
 
+func NewTestCertDifferentVersion(c cert.Certificate, v cert.Version, ca cert.Certificate, key []byte) (cert.Certificate, []byte) {
+	nc := &cert.TBSCertificate{
+		Version:        v,
+		Curve:          c.Curve(),
+		Name:           c.Name(),
+		Networks:       c.Networks(),
+		UnsafeNetworks: c.UnsafeNetworks(),
+		Groups:         c.Groups(),
+		NotBefore:      time.Unix(c.NotBefore().Unix(), 0),
+		NotAfter:       time.Unix(c.NotAfter().Unix(), 0),
+		PublicKey:      c.PublicKey(),
+		IsCA:           false,
+	}
+
+	c, err := nc.Sign(ca, ca.Curve(), key)
+	if err != nil {
+		panic(err)
+	}
+
+	pem, err := c.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+
+	return c, pem
+}
+
 func X25519Keypair() ([]byte, []byte) {
 	privkey := make([]byte, 32)
 	if _, err := io.ReadFull(rand.Reader, privkey); err != nil {

cmd/nebula-cert/ca.go

@@ -173,23 +173,26 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 
 	var passphrase []byte
 	if !isP11 && *cf.encryption {
-		for i := 0; i < 5; i++ {
+		passphrase = []byte(os.Getenv("NEBULA_CA_PASSPHRASE"))
-			out.Write([]byte("Enter passphrase: "))
-			passphrase, err = pr.ReadPassword()
-
-			if err == ErrNoTerminal {
-				return fmt.Errorf("out-key must be encrypted interactively")
-			} else if err != nil {
-				return fmt.Errorf("error reading passphrase: %s", err)
-			}
-
-			if len(passphrase) > 0 {
-				break
-			}
-		}
-
 		if len(passphrase) == 0 {
-			return fmt.Errorf("no passphrase specified, remove -encrypt flag to write out-key in plaintext")
+			for i := 0; i < 5; i++ {
+				out.Write([]byte("Enter passphrase: "))
+				passphrase, err = pr.ReadPassword()
+
+				if err == ErrNoTerminal {
+					return fmt.Errorf("out-key must be encrypted interactively")
+				} else if err != nil {
+					return fmt.Errorf("error reading passphrase: %s", err)
+				}
+
+				if len(passphrase) > 0 {
+					break
+				}
+			}
+
+			if len(passphrase) == 0 {
+				return fmt.Errorf("no passphrase specified, remove -encrypt flag to write out-key in plaintext")
+			}
 		}
 	}
 

cmd/nebula-cert/ca_test.go

@@ -171,6 +171,17 @@ func Test_ca(t *testing.T) {
 	assert.Equal(t, pwPromptOb, ob.String())
 	assert.Empty(t, eb.String())
 
+	// test encrypted key with passphrase environment variable
+	os.Remove(keyF.Name())
+	os.Remove(crtF.Name())
+	ob.Reset()
+	eb.Reset()
+	args = []string{"-version", "1", "-encrypt", "-name", "test", "-duration", "100m", "-groups", "1,2,3,4,5", "-out-crt", crtF.Name(), "-out-key", keyF.Name()}
+	os.Setenv("NEBULA_CA_PASSPHRASE", string(passphrase))
+	require.NoError(t, ca(args, ob, eb, testpw))
+	assert.Empty(t, eb.String())
+	os.Setenv("NEBULA_CA_PASSPHRASE", "")
+
 	// read encrypted key file and verify default params
 	rb, _ = os.ReadFile(keyF.Name())
 	k, _ := pem.Decode(rb)
@@ -189,7 +200,7 @@ func Test_ca(t *testing.T) {
 	assert.Empty(t, b)
 	assert.Len(t, lKey, 64)
 
-	// test when reading passsword results in an error
+	// test when reading password results in an error
 	os.Remove(keyF.Name())
 	os.Remove(crtF.Name())
 	ob.Reset()

cmd/nebula-cert/main.go

@@ -5,10 +5,28 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"runtime/debug"
+	"strings"
 )
 
+// A version string that can be set with
+//
+//	-ldflags "-X main.Build=SOMEVERSION"
+//
+// at compile-time.
 var Build string
 
+func init() {
+	if Build == "" {
+		info, ok := debug.ReadBuildInfo()
+		if !ok {
+			return
+		}
+
+		Build = strings.TrimPrefix(info.Main.Version, "v")
+	}
+}
+
 type helpError struct {
 	s string
 }

cmd/nebula-cert/sign.go

@@ -43,7 +43,7 @@ type signFlags struct {
 func newSignFlags() *signFlags {
 	sf := signFlags{set: flag.NewFlagSet("sign", flag.ContinueOnError)}
 	sf.set.Usage = func() {}
-	sf.version = sf.set.Uint("version", 0, "Optional: version of the certificate format to use, the default is to create both v1 and v2 certificates.")
+	sf.version = sf.set.Uint("version", 0, "Optional: version of the certificate format to use. The default is to match the version of the signing CA")
 	sf.caKeyPath = sf.set.String("ca-key", "ca.key", "Optional: path to the signing CA key")
 	sf.caCertPath = sf.set.String("ca-crt", "ca.crt", "Optional: path to the signing CA cert")
 	sf.name = sf.set.String("name", "", "Required: name of the cert, usually a hostname")
@@ -116,26 +116,28 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		// naively attempt to decode the private key as though it is not encrypted
 		caKey, _, curve, err = cert.UnmarshalSigningPrivateKeyFromPEM(rawCAKey)
 		if errors.Is(err, cert.ErrPrivateKeyEncrypted) {
-			// ask for a passphrase until we get one
 			var passphrase []byte
-			for i := 0; i < 5; i++ {
+			passphrase = []byte(os.Getenv("NEBULA_CA_PASSPHRASE"))
-				out.Write([]byte("Enter passphrase: "))
-				passphrase, err = pr.ReadPassword()
-
-				if errors.Is(err, ErrNoTerminal) {
-					return fmt.Errorf("ca-key is encrypted and must be decrypted interactively")
-				} else if err != nil {
-					return fmt.Errorf("error reading password: %s", err)
-				}
-
-				if len(passphrase) > 0 {
-					break
-				}
-			}
 			if len(passphrase) == 0 {
-				return fmt.Errorf("cannot open encrypted ca-key without passphrase")
+				// ask for a passphrase until we get one
-			}
+				for i := 0; i < 5; i++ {
+					out.Write([]byte("Enter passphrase: "))
+					passphrase, err = pr.ReadPassword()
 
+					if errors.Is(err, ErrNoTerminal) {
+						return fmt.Errorf("ca-key is encrypted and must be decrypted interactively")
+					} else if err != nil {
+						return fmt.Errorf("error reading password: %s", err)
+					}
+
+					if len(passphrase) > 0 {
+						break
+					}
+				}
+				if len(passphrase) == 0 {
+					return fmt.Errorf("cannot open encrypted ca-key without passphrase")
+				}
+			}
 			curve, caKey, _, err = cert.DecryptAndUnmarshalSigningPrivateKey(passphrase, rawCAKey)
 			if err != nil {
 				return fmt.Errorf("error while parsing encrypted ca-key: %s", err)
@@ -165,6 +167,10 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		return fmt.Errorf("ca certificate is expired")
 	}
 
+	if version == 0 {
+		version = caCert.Version()
+	}
+
 	// if no duration is given, expire one second before the root expires
 	if *sf.duration <= 0 {
 		*sf.duration = time.Until(caCert.NotAfter()) - time.Second*1
@@ -277,21 +283,19 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 	notBefore := time.Now()
 	notAfter := notBefore.Add(*sf.duration)
 
-	if version == 0 || version == cert.Version1 {
+	switch version {
-		// Make sure we at least have an ip
+	case cert.Version1:
+		// Make sure we have only one ipv4 address
 		if len(v4Networks) != 1 {
 			return newHelpErrorf("invalid -networks definition: v1 certificates can only have a single ipv4 address")
 		}
 
-		if version == cert.Version1 {
+		if len(v6Networks) > 0 {
-			// If we are asked to mint a v1 certificate only then we cant just ignore any v6 addresses
+			return newHelpErrorf("invalid -networks definition: v1 certificates can only contain ipv4 addresses")
-			if len(v6Networks) > 0 {
+		}
-				return newHelpErrorf("invalid -networks definition: v1 certificates can only be ipv4")
-			}
 
-			if len(v6UnsafeNetworks) > 0 {
+		if len(v6UnsafeNetworks) > 0 {
-				return newHelpErrorf("invalid -unsafe-networks definition: v1 certificates can only be ipv4")
+			return newHelpErrorf("invalid -unsafe-networks definition: v1 certificates can only contain ipv4 addresses")
-			}
 		}
 
 		t := &cert.TBSCertificate{
@@ -321,9 +325,8 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		}
 
 		crts = append(crts, nc)
-	}
 
-	if version == 0 || version == cert.Version2 {
+	case cert.Version2:
 		t := &cert.TBSCertificate{
 			Version:        cert.Version2,
 			Name:           *sf.name,
@@ -351,6 +354,9 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		}
 
 		crts = append(crts, nc)
+	default:
+		// this should be unreachable
+		return fmt.Errorf("invalid version: %d", version)
 	}
 
 	if !isP11 && *sf.inPubPath == "" {

cmd/nebula-cert/sign_test.go

@@ -55,7 +55,7 @@ func Test_signHelp(t *testing.T) {
 			"  -unsafe-networks string\n"+
 			"    \tOptional: comma separated list of ip address and network in CIDR notation. Unsafe networks this cert can route for\n"+
 			"  -version uint\n"+
-			"    \tOptional: version of the certificate format to use, the default is to create both v1 and v2 certificates.\n",
+			"    \tOptional: version of the certificate format to use. The default is to match the version of the signing CA\n",
 		ob.String(),
 	)
 }
@@ -204,7 +204,7 @@ func Test_signCert(t *testing.T) {
 	ob.Reset()
 	eb.Reset()
 	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "test", "-ip", "1.1.1.1/24", "-out-crt", "nope", "-out-key", "nope", "-duration", "100m", "-subnets", "100::100/100"}
-	assertHelpError(t, signCert(args, ob, eb, nopw), "invalid -unsafe-networks definition: v1 certificates can only be ipv4")
+	assertHelpError(t, signCert(args, ob, eb, nopw), "invalid -unsafe-networks definition: v1 certificates can only contain ipv4 addresses")
 	assert.Empty(t, ob.String())
 	assert.Empty(t, eb.String())
 
@@ -379,6 +379,15 @@ func Test_signCert(t *testing.T) {
 	assert.Equal(t, "Enter passphrase: ", ob.String())
 	assert.Empty(t, eb.String())
 
+	// test with the proper password in the environment
+	os.Remove(crtF.Name())
+	os.Remove(keyF.Name())
+	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "test", "-ip", "1.1.1.1/24", "-out-crt", crtF.Name(), "-out-key", keyF.Name(), "-duration", "100m", "-subnets", "10.1.1.1/32, ,   10.2.2.2/32   ,   ,  ,, 10.5.5.5/32", "-groups", "1,,   2    ,        ,,,3,4,5"}
+	os.Setenv("NEBULA_CA_PASSPHRASE", string(passphrase))
+	require.NoError(t, signCert(args, ob, eb, testpw))
+	assert.Empty(t, eb.String())
+	os.Setenv("NEBULA_CA_PASSPHRASE", "")
+
 	// test with the wrong password
 	ob.Reset()
 	eb.Reset()
@@ -389,6 +398,17 @@ func Test_signCert(t *testing.T) {
 	assert.Equal(t, "Enter passphrase: ", ob.String())
 	assert.Empty(t, eb.String())
 
+	// test with the wrong password in environment
+	ob.Reset()
+	eb.Reset()
+
+	os.Setenv("NEBULA_CA_PASSPHRASE", "invalid password")
+	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "test", "-ip", "1.1.1.1/24", "-out-crt", crtF.Name(), "-out-key", keyF.Name(), "-duration", "100m", "-subnets", "10.1.1.1/32, ,   10.2.2.2/32   ,   ,  ,, 10.5.5.5/32", "-groups", "1,,   2    ,        ,,,3,4,5"}
+	require.EqualError(t, signCert(args, ob, eb, nopw), "error while parsing encrypted ca-key: invalid passphrase or corrupt private key")
+	assert.Empty(t, ob.String())
+	assert.Empty(t, eb.String())
+	os.Setenv("NEBULA_CA_PASSPHRASE", "")
+
 	// test with the user not entering a password
 	ob.Reset()
 	eb.Reset()

cmd/nebula-service/main.go

@@ -4,6 +4,8 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"runtime/debug"
+	"strings"
 
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula"
@@ -18,6 +20,17 @@ import (
 // at compile-time.
 var Build string
 
+func init() {
+	if Build == "" {
+		info, ok := debug.ReadBuildInfo()
+		if !ok {
+			return
+		}
+
+		Build = strings.TrimPrefix(info.Main.Version, "v")
+	}
+}
+
 func main() {
 	serviceFlag := flag.String("service", "", "Control the system service.")
 	configPath := flag.String("config", "", "Path to either a file or directory to load configuration from")

cmd/nebula/main.go

@@ -4,6 +4,8 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"runtime/debug"
+	"strings"
 
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula"
@@ -18,6 +20,17 @@ import (
 // at compile-time.
 var Build string
 
+func init() {
+	if Build == "" {
+		info, ok := debug.ReadBuildInfo()
+		if !ok {
+			return
+		}
+
+		Build = strings.TrimPrefix(info.Main.Version, "v")
+	}
+}
+
 func main() {
 	configPath := flag.String("config", "", "Path to either a file or directory to load configuration from")
 	configTest := flag.Bool("test", false, "Test the config and print the end result. Non zero exit indicates a faulty config")

config/config.go

@@ -17,7 +17,7 @@ import (
 
 	"dario.cat/mergo"
 	"github.com/sirupsen/logrus"
-	"gopkg.in/yaml.v3"
+	"go.yaml.in/yaml/v3"
 )
 
 type C struct {

config/config_test.go

@@ -10,7 +10,7 @@ import (
 	"github.com/slackhq/nebula/test"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"gopkg.in/yaml.v3"
+	"go.yaml.in/yaml/v3"
 )
 
 func TestConfig_Load(t *testing.T) {

connection_manager.go

@@ -4,13 +4,16 @@ import (
 	"bytes"
 	"context"
 	"encoding/binary"
+	"fmt"
 	"net/netip"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/rcrowley/go-metrics"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/cert"
+	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/header"
 )
 
@@ -27,130 +30,124 @@ const (
 )
 
 type connectionManager struct {
-	in     map[uint32]struct{}
-	inLock *sync.RWMutex
-
-	out     map[uint32]struct{}
-	outLock *sync.RWMutex
-
 	// relayUsed holds which relay localIndexs are in use
 	relayUsed     map[uint32]struct{}
 	relayUsedLock *sync.RWMutex
 
-	hostMap                 *HostMap
+	hostMap      *HostMap
-	trafficTimer            *LockingTimerWheel[uint32]
+	trafficTimer *LockingTimerWheel[uint32]
-	intf                    *Interface
+	intf         *Interface
-	pendingDeletion         map[uint32]struct{}
+	punchy       *Punchy
-	punchy                  *Punchy
+
+	// Configuration settings
 	checkInterval           time.Duration
 	pendingDeletionInterval time.Duration
-	metricsTxPunchy         metrics.Counter
+	inactivityTimeout       atomic.Int64
+	dropInactive            atomic.Bool
+
+	metricsTxPunchy metrics.Counter
 
 	l *logrus.Logger
 }
 
-func newConnectionManager(ctx context.Context, l *logrus.Logger, intf *Interface, checkInterval, pendingDeletionInterval time.Duration, punchy *Punchy) *connectionManager {
+func newConnectionManagerFromConfig(l *logrus.Logger, c *config.C, hm *HostMap, p *Punchy) *connectionManager {
-	var max time.Duration
+	cm := &connectionManager{
-	if checkInterval < pendingDeletionInterval {
+		hostMap:         hm,
-		max = pendingDeletionInterval
+		l:               l,
-	} else {
+		punchy:          p,
-		max = checkInterval
+		relayUsed:       make(map[uint32]struct{}),
+		relayUsedLock:   &sync.RWMutex{},
+		metricsTxPunchy: metrics.GetOrRegisterCounter("messages.tx.punchy", nil),
 	}
 
-	nc := &connectionManager{
+	cm.reload(c, true)
-		hostMap:                 intf.hostMap,
+	c.RegisterReloadCallback(func(c *config.C) {
-		in:                      make(map[uint32]struct{}),
+		cm.reload(c, false)
-		inLock:                  &sync.RWMutex{},
+	})
-		out:                     make(map[uint32]struct{}),
-		outLock:                 &sync.RWMutex{},
-		relayUsed:               make(map[uint32]struct{}),
-		relayUsedLock:           &sync.RWMutex{},
-		trafficTimer:            NewLockingTimerWheel[uint32](time.Millisecond*500, max),
-		intf:                    intf,
-		pendingDeletion:         make(map[uint32]struct{}),
-		checkInterval:           checkInterval,
-		pendingDeletionInterval: pendingDeletionInterval,
-		punchy:                  punchy,
-		metricsTxPunchy:         metrics.GetOrRegisterCounter("messages.tx.punchy", nil),
-		l:                       l,
-	}
 
-	nc.Start(ctx)
+	return cm
-	return nc
 }
 
-func (n *connectionManager) In(localIndex uint32) {
+func (cm *connectionManager) reload(c *config.C, initial bool) {
-	n.inLock.RLock()
+	if initial {
-	// If this already exists, return
+		cm.checkInterval = time.Duration(c.GetInt("timers.connection_alive_interval", 5)) * time.Second
-	if _, ok := n.in[localIndex]; ok {
+		cm.pendingDeletionInterval = time.Duration(c.GetInt("timers.pending_deletion_interval", 10)) * time.Second
-		n.inLock.RUnlock()
+
-		return
+		// We want at least a minimum resolution of 500ms per tick so that we can hit these intervals
+		// pretty close to their configured duration.
+		// The inactivity duration is checked each time a hostinfo ticks through so we don't need the wheel to contain it.
+		minDuration := min(time.Millisecond*500, cm.checkInterval, cm.pendingDeletionInterval)
+		maxDuration := max(cm.checkInterval, cm.pendingDeletionInterval)
+		cm.trafficTimer = NewLockingTimerWheel[uint32](minDuration, maxDuration)
+	}
+
+	if initial || c.HasChanged("tunnels.inactivity_timeout") {
+		old := cm.getInactivityTimeout()
+		cm.inactivityTimeout.Store((int64)(c.GetDuration("tunnels.inactivity_timeout", 10*time.Minute)))
+		if !initial {
+			cm.l.WithField("oldDuration", old).
+				WithField("newDuration", cm.getInactivityTimeout()).
+				Info("Inactivity timeout has changed")
+		}
+	}
+
+	if initial || c.HasChanged("tunnels.drop_inactive") {
+		old := cm.dropInactive.Load()
+		cm.dropInactive.Store(c.GetBool("tunnels.drop_inactive", false))
+		if !initial {
+			cm.l.WithField("oldBool", old).
+				WithField("newBool", cm.dropInactive.Load()).
+				Info("Drop inactive setting has changed")
+		}
 	}
-	n.inLock.RUnlock()
-	n.inLock.Lock()
-	n.in[localIndex] = struct{}{}
-	n.inLock.Unlock()
 }
 
-func (n *connectionManager) Out(localIndex uint32) {
+func (cm *connectionManager) getInactivityTimeout() time.Duration {
-	n.outLock.RLock()
+	return (time.Duration)(cm.inactivityTimeout.Load())
-	// If this already exists, return
-	if _, ok := n.out[localIndex]; ok {
-		n.outLock.RUnlock()
-		return
-	}
-	n.outLock.RUnlock()
-	n.outLock.Lock()
-	n.out[localIndex] = struct{}{}
-	n.outLock.Unlock()
 }
 
-func (n *connectionManager) RelayUsed(localIndex uint32) {
+func (cm *connectionManager) In(h *HostInfo) {
-	n.relayUsedLock.RLock()
+	h.in.Store(true)
+}
+
+func (cm *connectionManager) Out(h *HostInfo) {
+	h.out.Store(true)
+}
+
+func (cm *connectionManager) RelayUsed(localIndex uint32) {
+	cm.relayUsedLock.RLock()
 	// If this already exists, return
-	if _, ok := n.relayUsed[localIndex]; ok {
+	if _, ok := cm.relayUsed[localIndex]; ok {
-		n.relayUsedLock.RUnlock()
+		cm.relayUsedLock.RUnlock()
 		return
 	}
-	n.relayUsedLock.RUnlock()
+	cm.relayUsedLock.RUnlock()
-	n.relayUsedLock.Lock()
+	cm.relayUsedLock.Lock()
-	n.relayUsed[localIndex] = struct{}{}
+	cm.relayUsed[localIndex] = struct{}{}
-	n.relayUsedLock.Unlock()
+	cm.relayUsedLock.Unlock()
 }
 
 // getAndResetTrafficCheck returns if there was any inbound or outbound traffic within the last tick and
 // resets the state for this local index
-func (n *connectionManager) getAndResetTrafficCheck(localIndex uint32) (bool, bool) {
+func (cm *connectionManager) getAndResetTrafficCheck(h *HostInfo, now time.Time) (bool, bool) {
-	n.inLock.Lock()
+	in := h.in.Swap(false)
-	n.outLock.Lock()
+	out := h.out.Swap(false)
-	_, in := n.in[localIndex]
+	if in || out {
-	_, out := n.out[localIndex]
+		h.lastUsed = now
-	delete(n.in, localIndex)
+	}
-	delete(n.out, localIndex)
-	n.inLock.Unlock()
-	n.outLock.Unlock()
 	return in, out
 }
 
-func (n *connectionManager) AddTrafficWatch(localIndex uint32) {
+// AddTrafficWatch must be called for every new HostInfo.
-	// Use a write lock directly because it should be incredibly rare that we are ever already tracking this index
+// We will continue to monitor the HostInfo until the tunnel is dropped.
-	n.outLock.Lock()
+func (cm *connectionManager) AddTrafficWatch(h *HostInfo) {
-	if _, ok := n.out[localIndex]; ok {
+	if h.out.Swap(true) == false {
-		n.outLock.Unlock()
+		cm.trafficTimer.Add(h.localIndexId, cm.checkInterval)
-		return
 	}
-	n.out[localIndex] = struct{}{}
-	n.trafficTimer.Add(localIndex, n.checkInterval)
-	n.outLock.Unlock()
 }
 
-func (n *connectionManager) Start(ctx context.Context) {
+func (cm *connectionManager) Start(ctx context.Context) {
-	go n.Run(ctx)
+	clockSource := time.NewTicker(cm.trafficTimer.t.tickDuration)
-}
-
-func (n *connectionManager) Run(ctx context.Context) {
-	//TODO: this tick should be based on the min wheel tick? Check firewall
-	clockSource := time.NewTicker(500 * time.Millisecond)
 	defer clockSource.Stop()
 
 	p := []byte("")
@@ -163,61 +160,61 @@ func (n *connectionManager) Run(ctx context.Context) {
 			return
 
 		case now := <-clockSource.C:
-			n.trafficTimer.Advance(now)
+			cm.trafficTimer.Advance(now)
 			for {
-				localIndex, has := n.trafficTimer.Purge()
+				localIndex, has := cm.trafficTimer.Purge()
 				if !has {
 					break
 				}
 
-				n.doTrafficCheck(localIndex, p, nb, out, now)
+				cm.doTrafficCheck(localIndex, p, nb, out, now)
 			}
 		}
 	}
 }
 
-func (n *connectionManager) doTrafficCheck(localIndex uint32, p, nb, out []byte, now time.Time) {
+func (cm *connectionManager) doTrafficCheck(localIndex uint32, p, nb, out []byte, now time.Time) {
-	decision, hostinfo, primary := n.makeTrafficDecision(localIndex, now)
+	decision, hostinfo, primary := cm.makeTrafficDecision(localIndex, now)
 
 	switch decision {
 	case deleteTunnel:
-		if n.hostMap.DeleteHostInfo(hostinfo) {
+		if cm.hostMap.DeleteHostInfo(hostinfo) {
 			// Only clearing the lighthouse cache if this is the last hostinfo for this vpn ip in the hostmap
-			n.intf.lightHouse.DeleteVpnAddrs(hostinfo.vpnAddrs)
+			cm.intf.lightHouse.DeleteVpnAddrs(hostinfo.vpnAddrs)
 		}
 
 	case closeTunnel:
-		n.intf.sendCloseTunnel(hostinfo)
+		cm.intf.sendCloseTunnel(hostinfo)
-		n.intf.closeTunnel(hostinfo)
+		cm.intf.closeTunnel(hostinfo)
 
 	case swapPrimary:
-		n.swapPrimary(hostinfo, primary)
+		cm.swapPrimary(hostinfo, primary)
 
 	case migrateRelays:
-		n.migrateRelayUsed(hostinfo, primary)
+		cm.migrateRelayUsed(hostinfo, primary)
 
 	case tryRehandshake:
-		n.tryRehandshake(hostinfo)
+		cm.tryRehandshake(hostinfo)
 
 	case sendTestPacket:
-		n.intf.SendMessageToHostInfo(header.Test, header.TestRequest, hostinfo, p, nb, out)
+		cm.intf.SendMessageToHostInfo(header.Test, header.TestRequest, hostinfo, p, nb, out)
 	}
 
-	n.resetRelayTrafficCheck(hostinfo)
+	cm.resetRelayTrafficCheck(hostinfo)
 }
 
-func (n *connectionManager) resetRelayTrafficCheck(hostinfo *HostInfo) {
+func (cm *connectionManager) resetRelayTrafficCheck(hostinfo *HostInfo) {
 	if hostinfo != nil {
-		n.relayUsedLock.Lock()
+		cm.relayUsedLock.Lock()
-		defer n.relayUsedLock.Unlock()
+		defer cm.relayUsedLock.Unlock()
 		// No need to migrate any relays, delete usage info now.
 		for _, idx := range hostinfo.relayState.CopyRelayForIdxs() {
-			delete(n.relayUsed, idx)
+			delete(cm.relayUsed, idx)
 		}
 	}
 }
 
-func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo) {
+func (cm *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo) {
 	relayFor := oldhostinfo.relayState.CopyAllRelayFor()
 
 	for _, r := range relayFor {
@@ -227,46 +224,51 @@ func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo)
 		var relayFrom netip.Addr
 		var relayTo netip.Addr
 		switch {
-		case ok && existing.State == Established:
+		case ok:
-			// This relay already exists in newhostinfo, then do nothing.
+			switch existing.State {
-			continue
+			case Established, PeerRequested, Disestablished:
-		case ok && existing.State == Requested:
+				// This relay already exists in newhostinfo, then do nothing.
-			// The relay exists in a Requested state; re-send the request
+				continue
-			index = existing.LocalIndex
+			case Requested:
-			switch r.Type {
+				// The relay exists in a Requested state; re-send the request
-			case TerminalType:
+				index = existing.LocalIndex
-				relayFrom = n.intf.myVpnAddrs[0]
+				switch r.Type {
-				relayTo = existing.PeerAddr
+				case TerminalType:
-			case ForwardingType:
+					relayFrom = cm.intf.myVpnAddrs[0]
-				relayFrom = existing.PeerAddr
+					relayTo = existing.PeerAddr
-				relayTo = newhostinfo.vpnAddrs[0]
+				case ForwardingType:
-			default:
+					relayFrom = existing.PeerAddr
-				// should never happen
+					relayTo = newhostinfo.vpnAddrs[0]
+				default:
+					// should never happen
+					panic(fmt.Sprintf("Migrating unknown relay type: %v", r.Type))
+				}
 			}
 		case !ok:
-			n.relayUsedLock.RLock()
+			cm.relayUsedLock.RLock()
-			if _, relayUsed := n.relayUsed[r.LocalIndex]; !relayUsed {
+			if _, relayUsed := cm.relayUsed[r.LocalIndex]; !relayUsed {
 				// The relay hasn't been used; don't migrate it.
-				n.relayUsedLock.RUnlock()
+				cm.relayUsedLock.RUnlock()
 				continue
 			}
-			n.relayUsedLock.RUnlock()
+			cm.relayUsedLock.RUnlock()
 			// The relay doesn't exist at all; create some relay state and send the request.
 			var err error
-			index, err = AddRelay(n.l, newhostinfo, n.hostMap, r.PeerAddr, nil, r.Type, Requested)
+			index, err = AddRelay(cm.l, newhostinfo, cm.hostMap, r.PeerAddr, nil, r.Type, Requested)
 			if err != nil {
-				n.l.WithError(err).Error("failed to migrate relay to new hostinfo")
+				cm.l.WithError(err).Error("failed to migrate relay to new hostinfo")
 				continue
 			}
 			switch r.Type {
 			case TerminalType:
-				relayFrom = n.intf.myVpnAddrs[0]
+				relayFrom = cm.intf.myVpnAddrs[0]
 				relayTo = r.PeerAddr
 			case ForwardingType:
 				relayFrom = r.PeerAddr
 				relayTo = newhostinfo.vpnAddrs[0]
 			default:
 				// should never happen
+				panic(fmt.Sprintf("Migrating unknown relay type: %v", r.Type))
 			}
 		}
 
@@ -279,12 +281,12 @@ func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo)
 		switch newhostinfo.GetCert().Certificate.Version() {
 		case cert.Version1:
 			if !relayFrom.Is4() {
-				n.l.Error("can not migrate v1 relay with a v6 network because the relay is not running a current nebula version")
+				cm.l.Error("can not migrate v1 relay with a v6 network because the relay is not running a current nebula version")
 				continue
 			}
 
 			if !relayTo.Is4() {
-				n.l.Error("can not migrate v1 relay with a v6 remote network because the relay is not running a current nebula version")
+				cm.l.Error("can not migrate v1 relay with a v6 remote network because the relay is not running a current nebula version")
 				continue
 			}
 
@@ -296,16 +298,16 @@ func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo)
 			req.RelayFromAddr = netAddrToProtoAddr(relayFrom)
 			req.RelayToAddr = netAddrToProtoAddr(relayTo)
 		default:
-			newhostinfo.logger(n.l).Error("Unknown certificate version found while attempting to migrate relay")
+			newhostinfo.logger(cm.l).Error("Unknown certificate version found while attempting to migrate relay")
 			continue
 		}
 
 		msg, err := req.Marshal()
 		if err != nil {
-			n.l.WithError(err).Error("failed to marshal Control message to migrate relay")
+			cm.l.WithError(err).Error("failed to marshal Control message to migrate relay")
 		} else {
-			n.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, make([]byte, 12), make([]byte, mtu))
+			cm.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, make([]byte, 12), make([]byte, mtu))
-			n.l.WithFields(logrus.Fields{
+			cm.l.WithFields(logrus.Fields{
 				"relayFrom":           req.RelayFromAddr,
 				"relayTo":             req.RelayToAddr,
 				"initiatorRelayIndex": req.InitiatorRelayIndex,
@@ -316,46 +318,44 @@ func (n *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo)
 	}
 }
 
-func (n *connectionManager) makeTrafficDecision(localIndex uint32, now time.Time) (trafficDecision, *HostInfo, *HostInfo) {
+func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Time) (trafficDecision, *HostInfo, *HostInfo) {
-	n.hostMap.RLock()
+	// Read lock the main hostmap to order decisions based on tunnels being the primary tunnel
-	defer n.hostMap.RUnlock()
+	cm.hostMap.RLock()
+	defer cm.hostMap.RUnlock()
 
-	hostinfo := n.hostMap.Indexes[localIndex]
+	hostinfo := cm.hostMap.Indexes[localIndex]
 	if hostinfo == nil {
-		n.l.WithField("localIndex", localIndex).Debugf("Not found in hostmap")
+		cm.l.WithField("localIndex", localIndex).Debugln("Not found in hostmap")
-		delete(n.pendingDeletion, localIndex)
 		return doNothing, nil, nil
 	}
 
-	if n.isInvalidCertificate(now, hostinfo) {
+	if cm.isInvalidCertificate(now, hostinfo) {
-		delete(n.pendingDeletion, hostinfo.localIndexId)
 		return closeTunnel, hostinfo, nil
 	}
 
-	primary := n.hostMap.Hosts[hostinfo.vpnAddrs[0]]
+	primary := cm.hostMap.Hosts[hostinfo.vpnAddrs[0]]
 	mainHostInfo := true
 	if primary != nil && primary != hostinfo {
 		mainHostInfo = false
 	}
 
 	// Check for traffic on this hostinfo
-	inTraffic, outTraffic := n.getAndResetTrafficCheck(localIndex)
+	inTraffic, outTraffic := cm.getAndResetTrafficCheck(hostinfo, now)
 
 	// A hostinfo is determined alive if there is incoming traffic
 	if inTraffic {
 		decision := doNothing
-		if n.l.Level >= logrus.DebugLevel {
+		if cm.l.Level >= logrus.DebugLevel {
-			hostinfo.logger(n.l).
+			hostinfo.logger(cm.l).
 				WithField("tunnelCheck", m{"state": "alive", "method": "passive"}).
 				Debug("Tunnel status")
 		}
-		delete(n.pendingDeletion, hostinfo.localIndexId)
+		hostinfo.pendingDeletion.Store(false)
 
 		if mainHostInfo {
 			decision = tryRehandshake
-
 		} else {
-			if n.shouldSwapPrimary(hostinfo, primary) {
+			if cm.shouldSwapPrimary(hostinfo) {
 				decision = swapPrimary
 			} else {
 				// migrate the relays to the primary, if in use.
@@ -363,46 +363,55 @@ func (n *connectionManager) makeTrafficDecision(localIndex uint32, now time.Time
 			}
 		}
 
-		n.trafficTimer.Add(hostinfo.localIndexId, n.checkInterval)
+		cm.trafficTimer.Add(hostinfo.localIndexId, cm.checkInterval)
 
 		if !outTraffic {
 			// Send a punch packet to keep the NAT state alive
-			n.sendPunch(hostinfo)
+			cm.sendPunch(hostinfo)
 		}
 
 		return decision, hostinfo, primary
 	}
 
-	if _, ok := n.pendingDeletion[hostinfo.localIndexId]; ok {
+	if hostinfo.pendingDeletion.Load() {
 		// We have already sent a test packet and nothing was returned, this hostinfo is dead
-		hostinfo.logger(n.l).
+		hostinfo.logger(cm.l).
 			WithField("tunnelCheck", m{"state": "dead", "method": "active"}).
 			Info("Tunnel status")
 
-		delete(n.pendingDeletion, hostinfo.localIndexId)
 		return deleteTunnel, hostinfo, nil
 	}
 
 	decision := doNothing
 	if hostinfo != nil && hostinfo.ConnectionState != nil && mainHostInfo {
 		if !outTraffic {
+			inactiveFor, isInactive := cm.isInactive(hostinfo, now)
+			if isInactive {
+				// Tunnel is inactive, tear it down
+				hostinfo.logger(cm.l).
+					WithField("inactiveDuration", inactiveFor).
+					WithField("primary", mainHostInfo).
+					Info("Dropping tunnel due to inactivity")
+
+				return closeTunnel, hostinfo, primary
+			}
+
 			// If we aren't sending or receiving traffic then its an unused tunnel and we don't to test the tunnel.
 			// Just maintain NAT state if configured to do so.
-			n.sendPunch(hostinfo)
+			cm.sendPunch(hostinfo)
-			n.trafficTimer.Add(hostinfo.localIndexId, n.checkInterval)
+			cm.trafficTimer.Add(hostinfo.localIndexId, cm.checkInterval)
 			return doNothing, nil, nil
-
 		}
 
-		if n.punchy.GetTargetEverything() {
+		if cm.punchy.GetTargetEverything() {
 			// This is similar to the old punchy behavior with a slight optimization.
 			// We aren't receiving traffic but we are sending it, punch on all known
 			// ips in case we need to re-prime NAT state
-			n.sendPunch(hostinfo)
+			cm.sendPunch(hostinfo)
 		}
 
-		if n.l.Level >= logrus.DebugLevel {
+		if cm.l.Level >= logrus.DebugLevel {
-			hostinfo.logger(n.l).
+			hostinfo.logger(cm.l).
 				WithField("tunnelCheck", m{"state": "testing", "method": "active"}).
 				Debug("Tunnel status")
 		}
@@ -411,17 +420,33 @@ func (n *connectionManager) makeTrafficDecision(localIndex uint32, now time.Time
 		decision = sendTestPacket
 
 	} else {
-		if n.l.Level >= logrus.DebugLevel {
+		if cm.l.Level >= logrus.DebugLevel {
-			hostinfo.logger(n.l).Debugf("Hostinfo sadness")
+			hostinfo.logger(cm.l).Debugf("Hostinfo sadness")
 		}
 	}
 
-	n.pendingDeletion[hostinfo.localIndexId] = struct{}{}
+	hostinfo.pendingDeletion.Store(true)
-	n.trafficTimer.Add(hostinfo.localIndexId, n.pendingDeletionInterval)
+	cm.trafficTimer.Add(hostinfo.localIndexId, cm.pendingDeletionInterval)
 	return decision, hostinfo, nil
 }
 
-func (n *connectionManager) shouldSwapPrimary(current, primary *HostInfo) bool {
+func (cm *connectionManager) isInactive(hostinfo *HostInfo, now time.Time) (time.Duration, bool) {
+	if cm.dropInactive.Load() == false {
+		// We aren't configured to drop inactive tunnels
+		return 0, false
+	}
+
+	inactiveDuration := now.Sub(hostinfo.lastUsed)
+	if inactiveDuration < cm.getInactivityTimeout() {
+		// It's not considered inactive
+		return inactiveDuration, false
+	}
+
+	// The tunnel is inactive
+	return inactiveDuration, true
+}
+
+func (cm *connectionManager) shouldSwapPrimary(current *HostInfo) bool {
 	// The primary tunnel is the most recent handshake to complete locally and should work entirely fine.
 	// If we are here then we have multiple tunnels for a host pair and neither side believes the same tunnel is primary.
 	// Let's sort this out.
@@ -429,83 +454,127 @@ func (n *connectionManager) shouldSwapPrimary(current, primary *HostInfo) bool {
 	// Only one side should swap because if both swap then we may never resolve to a single tunnel.
 	// vpn addr is static across all tunnels for this host pair so lets
 	// use that to determine if we should consider swapping.
-	if current.vpnAddrs[0].Compare(n.intf.myVpnAddrs[0]) < 0 {
+	if current.vpnAddrs[0].Compare(cm.intf.myVpnAddrs[0]) < 0 {
 		// Their primary vpn addr is less than mine. Do not swap.
 		return false
 	}
 
-	crt := n.intf.pki.getCertState().getCertificate(current.ConnectionState.myCert.Version())
+	crt := cm.intf.pki.getCertState().getCertificate(current.ConnectionState.myCert.Version())
+	if crt == nil {
+		//my cert was reloaded away. We should definitely swap from this tunnel
+		return true
+	}
 	// If this tunnel is using the latest certificate then we should swap it to primary for a bit and see if things
 	// settle down.
 	return bytes.Equal(current.ConnectionState.myCert.Signature(), crt.Signature())
 }
 
-func (n *connectionManager) swapPrimary(current, primary *HostInfo) {
+func (cm *connectionManager) swapPrimary(current, primary *HostInfo) {
-	n.hostMap.Lock()
+	cm.hostMap.Lock()
 	// Make sure the primary is still the same after the write lock. This avoids a race with a rehandshake.
-	if n.hostMap.Hosts[current.vpnAddrs[0]] == primary {
+	if cm.hostMap.Hosts[current.vpnAddrs[0]] == primary {
-		n.hostMap.unlockedMakePrimary(current)
+		cm.hostMap.unlockedMakePrimary(current)
 	}
-	n.hostMap.Unlock()
+	cm.hostMap.Unlock()
 }
 
-// isInvalidCertificate will check if we should destroy a tunnel if pki.disconnect_invalid is true and
+// isInvalidCertificate decides if we should destroy a tunnel.
-// the certificate is no longer valid. Block listed certificates will skip the pki.disconnect_invalid
+// returns true if pki.disconnect_invalid is true and the certificate is no longer valid.
-// check and return true.
+// Blocklisted certificates will skip the pki.disconnect_invalid check and return true.
-func (n *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostInfo) bool {
+func (cm *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostInfo) bool {
 	remoteCert := hostinfo.GetCert()
 	if remoteCert == nil {
-		return false
+		return false //don't tear down tunnels for handshakes in progress
 	}
 
-	caPool := n.intf.pki.GetCAPool()
+	caPool := cm.intf.pki.GetCAPool()
 	err := caPool.VerifyCachedCertificate(now, remoteCert)
 	if err == nil {
-		return false
+		return false //cert is still valid! yay!
-	}
+	} else if err == cert.ErrBlockListed { //avoiding errors.Is for speed
-
-	if !n.intf.disconnectInvalid.Load() && err != cert.ErrBlockListed {
 		// Block listed certificates should always be disconnected
+		hostinfo.logger(cm.l).WithError(err).
+			WithField("fingerprint", remoteCert.Fingerprint).
+			Info("Remote certificate is blocked, tearing down the tunnel")
+		return true
+	} else if cm.intf.disconnectInvalid.Load() {
+		hostinfo.logger(cm.l).WithError(err).
+			WithField("fingerprint", remoteCert.Fingerprint).
+			Info("Remote certificate is no longer valid, tearing down the tunnel")
+		return true
+	} else {
+		//if we reach here, the cert is no longer valid, but we're configured to keep tunnels from now-invalid certs open
 		return false
 	}
-
-	hostinfo.logger(n.l).WithError(err).
-		WithField("fingerprint", remoteCert.Fingerprint).
-		Info("Remote certificate is no longer valid, tearing down the tunnel")
-
-	return true
 }
 
-func (n *connectionManager) sendPunch(hostinfo *HostInfo) {
+func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
-	if !n.punchy.GetPunch() {
+	if !cm.punchy.GetPunch() {
 		// Punching is disabled
 		return
 	}
 
-	if n.punchy.GetTargetEverything() {
+	if cm.intf.lightHouse.IsAnyLighthouseAddr(hostinfo.vpnAddrs) {
-		hostinfo.remotes.ForEach(n.hostMap.GetPreferredRanges(), func(addr netip.AddrPort, preferred bool) {
+		// Do not punch to lighthouses, we assume our lighthouse update interval is good enough.
-			n.metricsTxPunchy.Inc(1)
+		// In the event the update interval is not sufficient to maintain NAT state then a publicly available lighthouse
-			n.intf.outside.WriteTo([]byte{1}, addr)
+		// would lose the ability to notify us and punchy.respond would become unreliable.
-		})
-
-	} else if hostinfo.remote.IsValid() {
-		n.metricsTxPunchy.Inc(1)
-		n.intf.outside.WriteTo([]byte{1}, hostinfo.remote)
-	}
-}
-
-func (n *connectionManager) tryRehandshake(hostinfo *HostInfo) {
-	cs := n.intf.pki.getCertState()
-	curCrt := hostinfo.ConnectionState.myCert
-	myCrt := cs.getCertificate(curCrt.Version())
-	if curCrt.Version() >= cs.initiatingVersion && bytes.Equal(curCrt.Signature(), myCrt.Signature()) == true {
-		// The current tunnel is using the latest certificate and version, no need to rehandshake.
 		return
 	}
 
-	n.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+	if cm.punchy.GetTargetEverything() {
-		WithField("reason", "local certificate is not current").
+		hostinfo.remotes.ForEach(cm.hostMap.GetPreferredRanges(), func(addr netip.AddrPort, preferred bool) {
-		Info("Re-handshaking with remote")
+			cm.metricsTxPunchy.Inc(1)
+			cm.intf.outside.WriteTo([]byte{1}, addr)
+		})
 
-	n.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+	} else if hostinfo.remote.IsValid() {
+		cm.metricsTxPunchy.Inc(1)
+		cm.intf.outside.WriteTo([]byte{1}, hostinfo.remote)
+	}
+}
+
+func (cm *connectionManager) tryRehandshake(hostinfo *HostInfo) {
+	cs := cm.intf.pki.getCertState()
+	curCrt := hostinfo.ConnectionState.myCert
+	curCrtVersion := curCrt.Version()
+	myCrt := cs.getCertificate(curCrtVersion)
+	if myCrt == nil {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("version", curCrtVersion).
+			WithField("reason", "local certificate removed").
+			Info("Re-handshaking with remote")
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		return
+	}
+	peerCrt := hostinfo.ConnectionState.peerCert
+	if peerCrt != nil && curCrtVersion < peerCrt.Certificate.Version() {
+		// if our certificate version is less than theirs, and we have a matching version available, rehandshake?
+		if cs.getCertificate(peerCrt.Certificate.Version()) != nil {
+			cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+				WithField("version", curCrtVersion).
+				WithField("peerVersion", peerCrt.Certificate.Version()).
+				WithField("reason", "local certificate version lower than peer, attempting to correct").
+				Info("Re-handshaking with remote")
+			cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], func(hh *HandshakeHostInfo) {
+				hh.initiatingVersionOverride = peerCrt.Certificate.Version()
+			})
+			return
+		}
+	}
+	if !bytes.Equal(curCrt.Signature(), myCrt.Signature()) {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("reason", "local certificate is not current").
+			Info("Re-handshaking with remote")
+
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		return
+	}
+	if curCrtVersion < cs.initiatingVersion {
+		cm.l.WithField("vpnAddrs", hostinfo.vpnAddrs).
+			WithField("reason", "current cert version < pki.initiatingVersion").
+			Info("Re-handshaking with remote")
+
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		return
+	}
 }

connection_manager_test.go

@@ -1,7 +1,6 @@
 package nebula
 
 import (
-	"context"
 	"crypto/ed25519"
 	"crypto/rand"
 	"net/netip"
@@ -23,7 +22,7 @@ func newTestLighthouse() *LightHouse {
 		addrMap:   map[netip.Addr]*RemoteList{},
 		queryChan: make(chan netip.Addr, 10),
 	}
-	lighthouses := map[netip.Addr]struct{}{}
+	lighthouses := []netip.Addr{}
 	staticList := map[netip.Addr]struct{}{}
 
 	lh.lighthouses.Store(&lighthouses)
@@ -64,10 +63,10 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 	ifce.pki.cs.Store(cs)
 
 	// Create manager
-	ctx, cancel := context.WithCancel(context.Background())
+	conf := config.NewC(l)
-	defer cancel()
+	punchy := NewPunchyFromConfig(l, conf)
-	punchy := NewPunchyFromConfig(l, config.NewC(l))
+	nc := newConnectionManagerFromConfig(l, conf, hostMap, punchy)
-	nc := newConnectionManager(ctx, l, ifce, 5, 10, punchy)
+	nc.intf = ifce
 	p := []byte("")
 	nb := make([]byte, 12, 12)
 	out := make([]byte, mtu)
@@ -85,32 +84,33 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 	nc.hostMap.unlockedAddHostInfo(hostinfo, ifce)
 
 	// We saw traffic out to vpnIp
-	nc.Out(hostinfo.localIndexId)
+	nc.Out(hostinfo)
-	nc.In(hostinfo.localIndexId)
+	nc.In(hostinfo)
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.False(t, hostinfo.pendingDeletion.Load())
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
-	assert.Contains(t, nc.out, hostinfo.localIndexId)
+	assert.True(t, hostinfo.out.Load())
+	assert.True(t, hostinfo.in.Load())
 
 	// Do a traffic check tick, should not be pending deletion but should not have any in/out packets recorded
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.False(t, hostinfo.pendingDeletion.Load())
-	assert.NotContains(t, nc.out, hostinfo.localIndexId)
+	assert.False(t, hostinfo.out.Load())
-	assert.NotContains(t, nc.in, hostinfo.localIndexId)
+	assert.False(t, hostinfo.in.Load())
 
 	// Do another traffic check tick, this host should be pending deletion now
-	nc.Out(hostinfo.localIndexId)
+	nc.Out(hostinfo)
+	assert.True(t, hostinfo.out.Load())
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.Contains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.True(t, hostinfo.pendingDeletion.Load())
-	assert.NotContains(t, nc.out, hostinfo.localIndexId)
+	assert.False(t, hostinfo.out.Load())
-	assert.NotContains(t, nc.in, hostinfo.localIndexId)
+	assert.False(t, hostinfo.in.Load())
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 
 	// Do a final traffic check tick, the host should now be removed
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.NotContains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs)
-	assert.NotContains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 	assert.NotContains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 }
 
@@ -146,10 +146,10 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 	ifce.pki.cs.Store(cs)
 
 	// Create manager
-	ctx, cancel := context.WithCancel(context.Background())
+	conf := config.NewC(l)
-	defer cancel()
+	punchy := NewPunchyFromConfig(l, conf)
-	punchy := NewPunchyFromConfig(l, config.NewC(l))
+	nc := newConnectionManagerFromConfig(l, conf, hostMap, punchy)
-	nc := newConnectionManager(ctx, l, ifce, 5, 10, punchy)
+	nc.intf = ifce
 	p := []byte("")
 	nb := make([]byte, 12, 12)
 	out := make([]byte, mtu)
@@ -167,33 +167,129 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 	nc.hostMap.unlockedAddHostInfo(hostinfo, ifce)
 
 	// We saw traffic out to vpnIp
-	nc.Out(hostinfo.localIndexId)
+	nc.Out(hostinfo)
-	nc.In(hostinfo.localIndexId)
+	nc.In(hostinfo)
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.vpnAddrs[0])
+	assert.True(t, hostinfo.in.Load())
+	assert.True(t, hostinfo.out.Load())
+	assert.False(t, hostinfo.pendingDeletion.Load())
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 
 	// Do a traffic check tick, should not be pending deletion but should not have any in/out packets recorded
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.False(t, hostinfo.pendingDeletion.Load())
-	assert.NotContains(t, nc.out, hostinfo.localIndexId)
+	assert.False(t, hostinfo.out.Load())
-	assert.NotContains(t, nc.in, hostinfo.localIndexId)
+	assert.False(t, hostinfo.in.Load())
 
 	// Do another traffic check tick, this host should be pending deletion now
-	nc.Out(hostinfo.localIndexId)
+	nc.Out(hostinfo)
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.Contains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.True(t, hostinfo.pendingDeletion.Load())
-	assert.NotContains(t, nc.out, hostinfo.localIndexId)
+	assert.False(t, hostinfo.out.Load())
-	assert.NotContains(t, nc.in, hostinfo.localIndexId)
+	assert.False(t, hostinfo.in.Load())
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 
 	// We saw traffic, should no longer be pending deletion
-	nc.In(hostinfo.localIndexId)
+	nc.In(hostinfo)
 	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
-	assert.NotContains(t, nc.pendingDeletion, hostinfo.localIndexId)
+	assert.False(t, hostinfo.pendingDeletion.Load())
-	assert.NotContains(t, nc.out, hostinfo.localIndexId)
+	assert.False(t, hostinfo.out.Load())
-	assert.NotContains(t, nc.in, hostinfo.localIndexId)
+	assert.False(t, hostinfo.in.Load())
+	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
+	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
+}
+
+func Test_NewConnectionManager_DisconnectInactive(t *testing.T) {
+	l := test.NewLogger()
+	localrange := netip.MustParsePrefix("10.1.1.1/24")
+	vpnAddrs := []netip.Addr{netip.MustParseAddr("172.1.1.2")}
+	preferredRanges := []netip.Prefix{localrange}
+
+	// Very incomplete mock objects
+	hostMap := newHostMap(l)
+	hostMap.preferredRanges.Store(&preferredRanges)
+
+	cs := &CertState{
+		initiatingVersion: cert.Version1,
+		privateKey:        []byte{},
+		v1Cert:            &dummyCert{version: cert.Version1},
+		v1HandshakeBytes:  []byte{},
+	}
+
+	lh := newTestLighthouse()
+	ifce := &Interface{
+		hostMap:          hostMap,
+		inside:           &test.NoopTun{},
+		outside:          &udp.NoopConn{},
+		firewall:         &Firewall{},
+		lightHouse:       lh,
+		pki:              &PKI{},
+		handshakeManager: NewHandshakeManager(l, hostMap, lh, &udp.NoopConn{}, defaultHandshakeConfig),
+		l:                l,
+	}
+	ifce.pki.cs.Store(cs)
+
+	// Create manager
+	conf := config.NewC(l)
+	conf.Settings["tunnels"] = map[string]any{
+		"drop_inactive": true,
+	}
+	punchy := NewPunchyFromConfig(l, conf)
+	nc := newConnectionManagerFromConfig(l, conf, hostMap, punchy)
+	assert.True(t, nc.dropInactive.Load())
+	nc.intf = ifce
+
+	// Add an ip we have established a connection w/ to hostmap
+	hostinfo := &HostInfo{
+		vpnAddrs:      vpnAddrs,
+		localIndexId:  1099,
+		remoteIndexId: 9901,
+	}
+	hostinfo.ConnectionState = &ConnectionState{
+		myCert: &dummyCert{version: cert.Version1},
+		H:      &noise.HandshakeState{},
+	}
+	nc.hostMap.unlockedAddHostInfo(hostinfo, ifce)
+
+	// Do a traffic check tick, in and out should be cleared but should not be pending deletion
+	nc.Out(hostinfo)
+	nc.In(hostinfo)
+	assert.True(t, hostinfo.out.Load())
+	assert.True(t, hostinfo.in.Load())
+
+	now := time.Now()
+	decision, _, _ := nc.makeTrafficDecision(hostinfo.localIndexId, now)
+	assert.Equal(t, tryRehandshake, decision)
+	assert.Equal(t, now, hostinfo.lastUsed)
+	assert.False(t, hostinfo.pendingDeletion.Load())
+	assert.False(t, hostinfo.out.Load())
+	assert.False(t, hostinfo.in.Load())
+
+	decision, _, _ = nc.makeTrafficDecision(hostinfo.localIndexId, now.Add(time.Second*5))
+	assert.Equal(t, doNothing, decision)
+	assert.Equal(t, now, hostinfo.lastUsed)
+	assert.False(t, hostinfo.pendingDeletion.Load())
+	assert.False(t, hostinfo.out.Load())
+	assert.False(t, hostinfo.in.Load())
+
+	// Do another traffic check tick, should still not be pending deletion
+	decision, _, _ = nc.makeTrafficDecision(hostinfo.localIndexId, now.Add(time.Second*10))
+	assert.Equal(t, doNothing, decision)
+	assert.Equal(t, now, hostinfo.lastUsed)
+	assert.False(t, hostinfo.pendingDeletion.Load())
+	assert.False(t, hostinfo.out.Load())
+	assert.False(t, hostinfo.in.Load())
+	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
+	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
+
+	// Finally advance beyond the inactivity timeout
+	decision, _, _ = nc.makeTrafficDecision(hostinfo.localIndexId, now.Add(time.Minute*10))
+	assert.Equal(t, closeTunnel, decision)
+	assert.Equal(t, now, hostinfo.lastUsed)
+	assert.False(t, hostinfo.pendingDeletion.Load())
+	assert.False(t, hostinfo.out.Load())
+	assert.False(t, hostinfo.in.Load())
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 }
@@ -264,10 +360,10 @@ func Test_NewConnectionManagerTest_DisconnectInvalid(t *testing.T) {
 	ifce.disconnectInvalid.Store(true)
 
 	// Create manager
-	ctx, cancel := context.WithCancel(context.Background())
+	conf := config.NewC(l)
-	defer cancel()
+	punchy := NewPunchyFromConfig(l, conf)
-	punchy := NewPunchyFromConfig(l, config.NewC(l))
+	nc := newConnectionManagerFromConfig(l, conf, hostMap, punchy)
-	nc := newConnectionManager(ctx, l, ifce, 5, 10, punchy)
+	nc.intf = ifce
 	ifce.connectionManager = nc
 
 	hostinfo := &HostInfo{
@@ -350,6 +446,10 @@ func (d *dummyCert) PublicKey() []byte {
 	return d.publicKey
 }
 
+func (d *dummyCert) MarshalPublicKeyPEM() []byte {
+	return cert.MarshalPublicKeyToPEM(d.curve, d.publicKey)
+}
+
 func (d *dummyCert) Signature() []byte {
 	return d.signature
 }

connection_state.go

@@ -50,11 +50,6 @@ func NewConnectionState(l *logrus.Logger, cs *CertState, crt cert.Certificate, i
 	}
 
 	static := noise.DHKey{Private: cs.privateKey, Public: crt.PublicKey()}
-
-	b := NewBits(ReplayWindow)
-	// Clear out bit 0, we never transmit it, and we don't want it showing as packet loss
-	b.Update(l, 0)
-
 	hs, err := noise.NewHandshakeState(noise.Config{
 		CipherSuite:   ncs,
 		Random:        rand.Reader,
@@ -74,7 +69,7 @@ func NewConnectionState(l *logrus.Logger, cs *CertState, crt cert.Certificate, i
 	ci := &ConnectionState{
 		H:         hs,
 		initiator: initiator,
-		window:    b,
+		window:    NewBits(ReplayWindow),
 		myCert:    crt,
 	}
 	// always start the counter from 2, as packet 1 and packet 2 are handshake packets.

control.go

@@ -26,14 +26,15 @@ type controlHostLister interface {
 }
 
 type Control struct {
-	f               *Interface
+	f                      *Interface
-	l               *logrus.Logger
+	l                      *logrus.Logger
-	ctx             context.Context
+	ctx                    context.Context
-	cancel          context.CancelFunc
+	cancel                 context.CancelFunc
-	sshStart        func()
+	sshStart               func()
-	statsStart      func()
+	statsStart             func()
-	dnsStart        func()
+	dnsStart               func()
-	lighthouseStart func()
+	lighthouseStart        func()
+	connectionManagerStart func(context.Context)
 }
 
 type ControlHostInfo struct {
@@ -63,6 +64,9 @@ func (c *Control) Start() {
 	if c.dnsStart != nil {
 		go c.dnsStart()
 	}
+	if c.connectionManagerStart != nil {
+		go c.connectionManagerStart(c.ctx)
+	}
 	if c.lighthouseStart != nil {
 		c.lighthouseStart()
 	}

control_test.go

@@ -53,7 +53,7 @@ func TestControl_GetHostInfoByVpnIp(t *testing.T) {
 		localIndexId:  201,
 		vpnAddrs:      []netip.Addr{vpnIp},
 		relayState: RelayState{
-			relays:         map[netip.Addr]struct{}{},
+			relays:         nil,
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},
 		},
@@ -72,7 +72,7 @@ func TestControl_GetHostInfoByVpnIp(t *testing.T) {
 		localIndexId:  201,
 		vpnAddrs:      []netip.Addr{vpnIp2},
 		relayState: RelayState{
-			relays:         map[netip.Addr]struct{}{},
+			relays:         nil,
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},
 		},

control_tester.go

@@ -1,5 +1,4 @@
 //go:build e2e_testing
-// +build e2e_testing
 
 package nebula
 
@@ -174,6 +173,10 @@ func (c *Control) GetHostmap() *HostMap {
 	return c.f.hostMap
 }
 
+func (c *Control) GetF() *Interface {
+	return c.f
+}
+
 func (c *Control) GetCertState() *CertState {
 	return c.f.pki.getCertState()
 }

e2e/handshakes_test.go

@@ -20,16 +20,17 @@ import (
 	"github.com/slackhq/nebula/udp"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"gopkg.in/yaml.v3"
+	"go.yaml.in/yaml/v3"
 )
 
 func BenchmarkHotPath(b *testing.B) {
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
-	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", nil)
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", nil)
 	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "them", "10.128.0.2/24", nil)
 
 	// Put their info in our lighthouse
 	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
 
 	// Start the servers
 	myControl.Start()
@@ -38,6 +39,9 @@ func BenchmarkHotPath(b *testing.B) {
 	r := router.NewR(b, myControl, theirControl)
 	r.CancelFlowLogs()
 
+	assertTunnel(b, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	b.ResetTimer()
+
 	for n := 0; n < b.N; n++ {
 		myControl.InjectTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me"))
 		_ = r.RouteForAllUntilTxTun(theirControl)
@@ -47,6 +51,39 @@ func BenchmarkHotPath(b *testing.B) {
 	theirControl.Stop()
 }
 
+func BenchmarkHotPathRelay(b *testing.B) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version1, ca, caKey, "me     ", "10.128.0.1/24", m{"relay": m{"use_relays": true}})
+	relayControl, relayVpnIpNet, relayUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "relay  ", "10.128.0.128/24", m{"relay": m{"am_relay": true}})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "them   ", "10.128.0.2/24", m{"relay": m{"use_relays": true}})
+
+	// Teach my how to get to the relay and that their can be reached via the relay
+	myControl.InjectLightHouseAddr(relayVpnIpNet[0].Addr(), relayUdpAddr)
+	myControl.InjectRelays(theirVpnIpNet[0].Addr(), []netip.Addr{relayVpnIpNet[0].Addr()})
+	relayControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(b, myControl, relayControl, theirControl)
+	r.CancelFlowLogs()
+
+	// Start the servers
+	myControl.Start()
+	relayControl.Start()
+	theirControl.Start()
+
+	assertTunnel(b, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
+	b.ResetTimer()
+
+	for n := 0; n < b.N; n++ {
+		myControl.InjectTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me"))
+		_ = r.RouteForAllUntilTxTun(theirControl)
+	}
+
+	myControl.Stop()
+	theirControl.Stop()
+	relayControl.Stop()
+}
+
 func TestGoodHandshake(t *testing.T) {
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
 	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", nil)
@@ -97,6 +134,41 @@ func TestGoodHandshake(t *testing.T) {
 	theirControl.Stop()
 }
 
+func TestGoodHandshakeNoOverlap(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "me", "10.128.0.1/24", nil)
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "them", "2001::69/24", nil) //look ma, cross-stack!
+
+	// Put their info in our lighthouse
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	empty := []byte{}
+	t.Log("do something to cause a handshake")
+	myControl.GetF().SendMessageToVpnAddr(header.Test, header.MessageNone, theirVpnIpNet[0].Addr(), empty, empty, empty)
+
+	t.Log("Have them consume my stage 0 packet. They have a tunnel now")
+	theirControl.InjectUDPPacket(myControl.GetFromUDP(true))
+
+	t.Log("Get their stage 1 packet")
+	stage1Packet := theirControl.GetFromUDP(true)
+
+	t.Log("Have me consume their stage 1 packet. I have a tunnel now")
+	myControl.InjectUDPPacket(stage1Packet)
+
+	t.Log("Wait until we see a test packet come through to make sure we give the tunnel time to complete")
+	myControl.WaitForType(header.Test, 0, theirControl)
+
+	t.Log("Make sure our host infos are correct")
+	assertHostInfoPair(t, myUdpAddr, theirUdpAddr, myVpnIpNet, theirVpnIpNet, myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
 func TestWrongResponderHandshake(t *testing.T) {
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
 
@@ -464,6 +536,35 @@ func TestRelays(t *testing.T) {
 	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
 }
 
+func TestRelaysDontCareAboutIps(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "me     ", "10.128.0.1/24", m{"relay": m{"use_relays": true}})
+	relayControl, relayVpnIpNet, relayUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "relay  ", "2001::9999/24", m{"relay": m{"am_relay": true}})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "them   ", "10.128.0.2/24", m{"relay": m{"use_relays": true}})
+
+	// Teach my how to get to the relay and that their can be reached via the relay
+	myControl.InjectLightHouseAddr(relayVpnIpNet[0].Addr(), relayUdpAddr)
+	myControl.InjectRelays(theirVpnIpNet[0].Addr(), []netip.Addr{relayVpnIpNet[0].Addr()})
+	relayControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(t, myControl, relayControl, theirControl)
+	defer r.RenderFlow()
+
+	// Start the servers
+	myControl.Start()
+	relayControl.Start()
+	theirControl.Start()
+
+	t.Log("Trigger a handshake from me to them via the relay")
+	myControl.InjectTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me"))
+
+	p := r.RouteForAllUntilTxTun(theirControl)
+	r.Log("Assert the tunnel works")
+	assertUdpPacket(t, []byte("Hi from me"), p, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), 80, 80)
+	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
+}
+
 func TestReestablishRelays(t *testing.T) {
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
 	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version1, ca, caKey, "me     ", "10.128.0.1/24", m{"relay": m{"use_relays": true}})
@@ -506,7 +607,7 @@ func TestReestablishRelays(t *testing.T) {
 	curIndexes := len(myControl.GetHostmap().Indexes)
 	for curIndexes >= start {
 		curIndexes = len(myControl.GetHostmap().Indexes)
-		r.Logf("Wait for the dead index to go away:start=%v indexes, currnet=%v indexes", start, curIndexes)
+		r.Logf("Wait for the dead index to go away:start=%v indexes, current=%v indexes", start, curIndexes)
 		myControl.InjectTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me should fail"))
 
 		r.RouteForAllExitFunc(func(p *udp.Packet, c *nebula.Control) router.ExitType {
@@ -1052,6 +1153,9 @@ func TestRehandshakingLoser(t *testing.T) {
 	t.Log("Stand up a tunnel between me and them")
 	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
 
+	myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+	theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+
 	r.RenderHostmaps("Starting hostmaps", myControl, theirControl)
 
 	r.Log("Renew their certificate and spin until mine sees it")
@@ -1224,3 +1328,109 @@ func TestV2NonPrimaryWithLighthouse(t *testing.T) {
 	myControl.Stop()
 	theirControl.Stop()
 }
+
+func TestV2NonPrimaryWithOffNetLighthouse(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	lhControl, lhVpnIpNet, lhUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "lh  ", "2001::1/64", m{"lighthouse": m{"am_lighthouse": true}})
+
+	o := m{
+		"static_host_map": m{
+			lhVpnIpNet[0].Addr().String(): []string{lhUdpAddr.String()},
+		},
+		"lighthouse": m{
+			"hosts": []string{lhVpnIpNet[0].Addr().String()},
+			"local_allow_list": m{
+				// Try and block our lighthouse updates from using the actual addresses assigned to this computer
+				// If we start discovering addresses the test router doesn't know about then test traffic cant flow
+				"10.0.0.0/24": true,
+				"::/0":        false,
+			},
+		},
+	}
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "me  ", "10.128.0.2/24, ff::2/64", o)
+	theirControl, theirVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "them", "10.128.0.3/24, ff::3/64", o)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(t, lhControl, myControl, theirControl)
+	defer r.RenderFlow()
+
+	// Start the servers
+	lhControl.Start()
+	myControl.Start()
+	theirControl.Start()
+
+	t.Log("Stand up an ipv6 tunnel between me and them")
+	assert.True(t, myVpnIpNet[1].Addr().Is6())
+	assert.True(t, theirVpnIpNet[1].Addr().Is6())
+	assertTunnel(t, myVpnIpNet[1].Addr(), theirVpnIpNet[1].Addr(), myControl, theirControl, r)
+
+	lhControl.Stop()
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestGoodHandshakeUnsafeDest(t *testing.T) {
+	unsafePrefix := "192.168.6.0/24"
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(cert.Version2, ca, caKey, "spooky", "10.128.0.2/24", netip.MustParseAddrPort("10.64.0.2:4242"), unsafePrefix, nil)
+	route := m{"route": unsafePrefix, "via": theirVpnIpNet[0].Addr().String()}
+	myCfg := m{
+		"tun": m{
+			"unsafe_routes": []m{route},
+		},
+	}
+	myControl, myVpnIpNet, myUdpAddr, myConfig := newSimpleServer(cert.Version2, ca, caKey, "me", "10.128.0.1/24", myCfg)
+	t.Logf("my config %v", myConfig)
+	// Put their info in our lighthouse
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+
+	spookyDest := netip.MustParseAddr("192.168.6.4")
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	t.Log("Send a udp packet through to begin standing up the tunnel, this should come out the other side")
+	myControl.InjectTunUDPPacket(spookyDest, 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me"))
+
+	t.Log("Have them consume my stage 0 packet. They have a tunnel now")
+	theirControl.InjectUDPPacket(myControl.GetFromUDP(true))
+
+	t.Log("Get their stage 1 packet so that we can play with it")
+	stage1Packet := theirControl.GetFromUDP(true)
+
+	t.Log("I consume a garbage packet with a proper nebula header for our tunnel")
+	// this should log a statement and get ignored, allowing the real handshake packet to complete the tunnel
+	badPacket := stage1Packet.Copy()
+	badPacket.Data = badPacket.Data[:len(badPacket.Data)-header.Len]
+	myControl.InjectUDPPacket(badPacket)
+
+	t.Log("Have me consume their real stage 1 packet. I have a tunnel now")
+	myControl.InjectUDPPacket(stage1Packet)
+
+	t.Log("Wait until we see my cached packet come through")
+	myControl.WaitForType(1, 0, theirControl)
+
+	t.Log("Make sure our host infos are correct")
+	assertHostInfoPair(t, myUdpAddr, theirUdpAddr, myVpnIpNet, theirVpnIpNet, myControl, theirControl)
+
+	t.Log("Get that cached packet and make sure it looks right")
+	myCachedPacket := theirControl.GetFromTun(true)
+	assertUdpPacket(t, []byte("Hi from me"), myCachedPacket, myVpnIpNet[0].Addr(), spookyDest, 80, 80)
+
+	//reply
+	theirControl.InjectTunUDPPacket(myVpnIpNet[0].Addr(), 80, spookyDest, 80, []byte("Hi from the spookyman"))
+	//wait for reply
+	theirControl.WaitForType(1, 0, myControl)
+	theirCachedPacket := myControl.GetFromTun(true)
+	assertUdpPacket(t, []byte("Hi from the spookyman"), theirCachedPacket, spookyDest, myVpnIpNet[0].Addr(), 80, 80)
+
+	t.Log("Do a bidirectional tunnel test")
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+	myControl.Stop()
+	theirControl.Stop()
+}

e2e/helpers_test.go

@@ -22,15 +22,14 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/e2e/router"
 	"github.com/stretchr/testify/assert"
-	"gopkg.in/yaml.v3"
+	"github.com/stretchr/testify/require"
+	"go.yaml.in/yaml/v3"
 )
 
 type m = map[string]any
 
 // newSimpleServer creates a nebula instance with many assumptions
 func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
-	l := NewTestLogger()
-
 	var vpnNetworks []netip.Prefix
 	for _, sn := range strings.Split(sVpnNetworks, ",") {
 		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
@@ -56,7 +55,54 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 		budpIp[3] = 239
 		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
 	}
-	_, _, myPrivKey, myPEM := cert_test.NewTestCert(v, cert.Curve_CURVE25519, caCrt, caKey, name, time.Now(), time.Now().Add(5*time.Minute), vpnNetworks, nil, []string{})
+	return newSimpleServerWithUdp(v, caCrt, caKey, name, sVpnNetworks, udpAddr, overrides)
+}
+
+func newSimpleServerWithUdp(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, udpAddr netip.AddrPort, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	return newSimpleServerWithUdpAndUnsafeNetworks(v, caCrt, caKey, name, sVpnNetworks, udpAddr, "", overrides)
+}
+
+func newSimpleServerWithUdpAndUnsafeNetworks(v cert.Version, caCrt cert.Certificate, caKey []byte, name string, sVpnNetworks string, udpAddr netip.AddrPort, sUnsafeNetworks string, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	l := NewTestLogger()
+
+	var vpnNetworks []netip.Prefix
+	for _, sn := range strings.Split(sVpnNetworks, ",") {
+		vpnIpNet, err := netip.ParsePrefix(strings.TrimSpace(sn))
+		if err != nil {
+			panic(err)
+		}
+		vpnNetworks = append(vpnNetworks, vpnIpNet)
+	}
+
+	if len(vpnNetworks) == 0 {
+		panic("no vpn networks")
+	}
+
+	firewallInbound := []m{{
+		"proto": "any",
+		"port":  "any",
+		"host":  "any",
+	}}
+
+	var unsafeNetworks []netip.Prefix
+	if sUnsafeNetworks != "" {
+		firewallInbound = []m{{
+			"proto":      "any",
+			"port":       "any",
+			"host":       "any",
+			"local_cidr": "0.0.0.0/0",
+		}}
+
+		for _, sn := range strings.Split(sUnsafeNetworks, ",") {
+			x, err := netip.ParsePrefix(strings.TrimSpace(sn))
+			if err != nil {
+				panic(err)
+			}
+			unsafeNetworks = append(unsafeNetworks, x)
+		}
+	}
+
+	_, _, myPrivKey, myPEM := cert_test.NewTestCert(v, cert.Curve_CURVE25519, caCrt, caKey, name, time.Now(), time.Now().Add(5*time.Minute), vpnNetworks, unsafeNetworks, []string{})
 
 	caB, err := caCrt.MarshalPEM()
 	if err != nil {
@@ -76,11 +122,7 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 				"port":  "any",
 				"host":  "any",
 			}},
-			"inbound": []m{{
+			"inbound": firewallInbound,
-				"proto": "any",
-				"port":  "any",
-				"host":  "any",
-			}},
 		},
 		//"handshakes": m{
 		//	"try_interval": "1s",
@@ -129,6 +171,109 @@ func newSimpleServer(v cert.Version, caCrt cert.Certificate, caKey []byte, name
 	return control, vpnNetworks, udpAddr, c
 }
 
+// newServer creates a nebula instance with fewer assumptions
+func newServer(caCrt []cert.Certificate, certs []cert.Certificate, key []byte, overrides m) (*nebula.Control, []netip.Prefix, netip.AddrPort, *config.C) {
+	l := NewTestLogger()
+
+	vpnNetworks := certs[len(certs)-1].Networks()
+
+	var udpAddr netip.AddrPort
+	if vpnNetworks[0].Addr().Is4() {
+		budpIp := vpnNetworks[0].Addr().As4()
+		budpIp[1] -= 128
+		udpAddr = netip.AddrPortFrom(netip.AddrFrom4(budpIp), 4242)
+	} else {
+		budpIp := vpnNetworks[0].Addr().As16()
+		// beef for funsies
+		budpIp[2] = 190
+		budpIp[3] = 239
+		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
+	}
+
+	caStr := ""
+	for _, ca := range caCrt {
+		x, err := ca.MarshalPEM()
+		if err != nil {
+			panic(err)
+		}
+		caStr += string(x)
+	}
+	certStr := ""
+	for _, c := range certs {
+		x, err := c.MarshalPEM()
+		if err != nil {
+			panic(err)
+		}
+		certStr += string(x)
+	}
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": certStr,
+			"key":  string(key),
+		},
+		//"tun": m{"disabled": true},
+		"firewall": m{
+			"outbound": []m{{
+				"proto": "any",
+				"port":  "any",
+				"host":  "any",
+			}},
+			"inbound": []m{{
+				"proto": "any",
+				"port":  "any",
+				"host":  "any",
+			}},
+		},
+		//"handshakes": m{
+		//	"try_interval": "1s",
+		//},
+		"listen": m{
+			"host": udpAddr.Addr().String(),
+			"port": udpAddr.Port(),
+		},
+		"logging": m{
+			"timestamp_format": fmt.Sprintf("%v 15:04:05.000000", certs[0].Name()),
+			"level":            l.Level.String(),
+		},
+		"timers": m{
+			"pending_deletion_interval": 2,
+			"connection_alive_interval": 2,
+		},
+	}
+
+	if overrides != nil {
+		final := m{}
+		err := mergo.Merge(&final, overrides, mergo.WithAppendSlice)
+		if err != nil {
+			panic(err)
+		}
+		err = mergo.Merge(&final, mc, mergo.WithAppendSlice)
+		if err != nil {
+			panic(err)
+		}
+		mc = final
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	c := config.NewC(l)
+	cStr := string(cb)
+	c.LoadString(cStr)
+
+	control, err := nebula.Main(c, false, "e2e-test", l, nil)
+
+	if err != nil {
+		panic(err)
+	}
+
+	return control, vpnNetworks, udpAddr, c
+}
+
 type doneCb func()
 
 func deadline(t *testing.T, seconds time.Duration) doneCb {
@@ -147,7 +292,7 @@ func deadline(t *testing.T, seconds time.Duration) doneCb {
 	}
 }
 
-func assertTunnel(t *testing.T, vpnIpA, vpnIpB netip.Addr, controlA, controlB *nebula.Control, r *router.R) {
+func assertTunnel(t testing.TB, vpnIpA, vpnIpB netip.Addr, controlA, controlB *nebula.Control, r *router.R) {
 	// Send a packet from them to me
 	controlB.InjectTunUDPPacket(vpnIpA, 80, vpnIpB, 90, []byte("Hi from B"))
 	bPacket := r.RouteForAllUntilTxTun(controlA)
@@ -159,14 +304,14 @@ func assertTunnel(t *testing.T, vpnIpA, vpnIpB netip.Addr, controlA, controlB *n
 	assertUdpPacket(t, []byte("Hello from A"), aPacket, vpnIpA, vpnIpB, 90, 80)
 }
 
-func assertHostInfoPair(t *testing.T, addrA, addrB netip.AddrPort, vpnNetsA, vpnNetsB []netip.Prefix, controlA, controlB *nebula.Control) {
+func assertHostInfoPair(t testing.TB, addrA, addrB netip.AddrPort, vpnNetsA, vpnNetsB []netip.Prefix, controlA, controlB *nebula.Control) {
 	// Get both host infos
 	//TODO: CERT-V2 we may want to loop over each vpnAddr and assert all the things
 	hBinA := controlA.GetHostInfoByVpnAddr(vpnNetsB[0].Addr(), false)
-	assert.NotNil(t, hBinA, "Host B was not found by vpnAddr in controlA")
+	require.NotNil(t, hBinA, "Host B was not found by vpnAddr in controlA")
 
 	hAinB := controlB.GetHostInfoByVpnAddr(vpnNetsA[0].Addr(), false)
-	assert.NotNil(t, hAinB, "Host A was not found by vpnAddr in controlB")
+	require.NotNil(t, hAinB, "Host A was not found by vpnAddr in controlB")
 
 	// Check that both vpn and real addr are correct
 	assert.EqualValues(t, getAddrs(vpnNetsB), hBinA.VpnAddrs, "Host B VpnIp is wrong in control A")
@@ -180,7 +325,7 @@ func assertHostInfoPair(t *testing.T, addrA, addrB netip.AddrPort, vpnNetsA, vpn
 	assert.Equal(t, hBinA.RemoteIndex, hAinB.LocalIndex, "Host B remote index does not match host A local index")
 }
 
-func assertUdpPacket(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
+func assertUdpPacket(t testing.TB, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
 	if toIp.Is6() {
 		assertUdpPacket6(t, expected, b, fromIp, toIp, fromPort, toPort)
 	} else {
@@ -188,7 +333,7 @@ func assertUdpPacket(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr,
 	}
 }
 
-func assertUdpPacket6(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
+func assertUdpPacket6(t testing.TB, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
 	packet := gopacket.NewPacket(b, layers.LayerTypeIPv6, gopacket.Lazy)
 	v6 := packet.Layer(layers.LayerTypeIPv6).(*layers.IPv6)
 	assert.NotNil(t, v6, "No ipv6 data found")
@@ -207,7 +352,7 @@ func assertUdpPacket6(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr,
 	assert.Equal(t, expected, data.Payload(), "Data was incorrect")
 }
 
-func assertUdpPacket4(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
+func assertUdpPacket4(t testing.TB, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
 	packet := gopacket.NewPacket(b, layers.LayerTypeIPv4, gopacket.Lazy)
 	v4 := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4)
 	assert.NotNil(t, v4, "No ipv4 data found")

e2e/router/router.go

@@ -700,6 +700,7 @@ func (r *R) FlushAll() {
 			r.Unlock()
 			panic("Can't FlushAll for host: " + p.To.String())
 		}
+		receiver.InjectUDPPacket(p)
 		r.Unlock()
 	}
 }

e2e/snat_test.go

@@ -0,0 +1,400 @@
+//go:build e2e_testing
+// +build e2e_testing
+
+package e2e
+
+import (
+	"encoding/binary"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/slackhq/nebula/cert"
+	"github.com/slackhq/nebula/cert_test"
+	"github.com/slackhq/nebula/e2e/router"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// parseIPv4UDPPacket extracts source/dest IPs, ports, and payload from an IPv4 UDP packet.
+func parseIPv4UDPPacket(t testing.TB, pkt []byte) (srcIP, dstIP netip.Addr, srcPort, dstPort uint16, payload []byte) {
+	t.Helper()
+	require.True(t, len(pkt) >= 28, "packet too short for IPv4+UDP header")
+	require.Equal(t, byte(0x45), pkt[0]&0xF0|pkt[0]&0x0F, "not a simple IPv4 packet (IHL!=5)")
+
+	srcIP, _ = netip.AddrFromSlice(pkt[12:16])
+	dstIP, _ = netip.AddrFromSlice(pkt[16:20])
+
+	ihl := int(pkt[0]&0x0F) * 4
+	require.True(t, len(pkt) >= ihl+8, "packet too short for UDP header")
+	srcPort = binary.BigEndian.Uint16(pkt[ihl : ihl+2])
+	dstPort = binary.BigEndian.Uint16(pkt[ihl+2 : ihl+4])
+	udpLen := binary.BigEndian.Uint16(pkt[ihl+4 : ihl+6])
+	payload = pkt[ihl+8 : ihl+int(udpLen)]
+	return
+}
+
+func TestSNAT_IPv6OnlyPeer_IPv4UnsafeTraffic(t *testing.T) {
+	// Scenario: Two IPv6-only VPN nodes. The "router" node has unsafe networks
+	// (192.168.0.0/16) in its cert and a configured SNAT address. The "sender"
+	// node has an unsafe route for 192.168.0.0/16 via the router.
+	//
+	// When sender injects an IPv4 packet destined for the unsafe network, it
+	// gets tunneled to the router. The router's firewall detects this is IPv4
+	// from an IPv6-only peer and applies SNAT, rewriting the source IP to the
+	// SNAT address before delivering it to TUN.
+	//
+	// When a reply comes back from TUN addressed to the SNAT address, the
+	// router un-SNATs it (restoring the original destination) and tunnels it
+	// back to the sender.
+
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	unsafePrefix := "192.168.0.0/16"
+	snatAddr := netip.MustParseAddr("169.254.42.42")
+
+	// Router: IPv6-only with unsafe networks and a manual SNAT address.
+	// Override inbound firewall with local_cidr: "any" so both IPv4 (unsafe)
+	// and IPv6 (VPN) traffic is accepted.
+	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
+		cert.Version2, ca, caKey, "router", "ff::1/64",
+		netip.MustParseAddrPort("[beef::1]:4242"),
+		unsafePrefix,
+		m{
+			"firewall": m{
+				"inbound": []m{{
+					"proto":      "any",
+					"port":       "any",
+					"host":       "any",
+					"local_cidr": "any",
+				}},
+			},
+			"tun": m{
+				"snat_address_for_4over6": snatAddr.String(),
+			},
+		},
+	)
+
+	// Sender: IPv6-only with an unsafe route via the router
+	senderControl, _, _, _ := newSimpleServerWithUdp(
+		cert.Version2, ca, caKey, "sender", "ff::2/64",
+		netip.MustParseAddrPort("[beef::2]:4242"),
+		m{
+			"tun": m{
+				"unsafe_routes": []m{
+					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
+				},
+			},
+		},
+	)
+
+	// Tell sender where the router lives
+	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
+
+	// Build the router and start both nodes
+	r := router.NewR(t, routerControl, senderControl)
+	defer r.RenderFlow()
+
+	routerControl.Start()
+	senderControl.Start()
+
+	// --- Outbound: sender -> IPv4 unsafe dest (via router with SNAT) ---
+
+	origSrcIP := netip.MustParseAddr("10.0.0.1")
+	unsafeDest := netip.MustParseAddr("192.168.1.1")
+	var origSrcPort uint16 = 12345
+	var dstPort uint16 = 80
+
+	t.Log("Sender injects an IPv4 packet to the unsafe network")
+	senderControl.InjectTunUDPPacket(unsafeDest, dstPort, origSrcIP, origSrcPort, []byte("snat me"))
+
+	t.Log("Route packets (handshake + data) until the router gets the packet on TUN")
+	snatPkt := r.RouteForAllUntilTxTun(routerControl)
+
+	t.Log("Verify the packet was SNATted")
+	gotSrcIP, gotDstIP, gotSrcPort, gotDstPort, gotPayload := parseIPv4UDPPacket(t, snatPkt)
+	assert.Equal(t, snatAddr, gotSrcIP, "source IP should be rewritten to the SNAT address")
+	assert.Equal(t, unsafeDest, gotDstIP, "destination IP should be unchanged")
+	assert.Equal(t, dstPort, gotDstPort, "destination port should be unchanged")
+	assert.Equal(t, []byte("snat me"), gotPayload, "payload should be unchanged")
+
+	// Capture the SNAT port (may differ from original if port was remapped)
+	snatPort := gotSrcPort
+	t.Logf("SNAT port: %d (original: %d)", snatPort, origSrcPort)
+
+	// --- Return: reply from unsafe dest -> un-SNATted back to sender ---
+
+	t.Log("Router injects a reply packet from the unsafe dest to the SNAT address")
+	routerControl.InjectTunUDPPacket(snatAddr, snatPort, unsafeDest, dstPort, []byte("reply from unsafe"))
+
+	t.Log("Route until sender gets the reply on TUN")
+	replyPkt := r.RouteForAllUntilTxTun(senderControl)
+
+	t.Log("Verify the reply was un-SNATted")
+	replySrcIP, replyDstIP, replySrcPort, replyDstPort, replyPayload := parseIPv4UDPPacket(t, replyPkt)
+	assert.Equal(t, unsafeDest, replySrcIP, "reply source should be the unsafe dest")
+	assert.Equal(t, origSrcIP, replyDstIP, "reply dest should be the original source IP (un-SNATted)")
+	assert.Equal(t, dstPort, replySrcPort, "reply source port should be the unsafe dest port")
+	assert.Equal(t, origSrcPort, replyDstPort, "reply dest port should be the original source port (un-SNATted)")
+	assert.Equal(t, []byte("reply from unsafe"), replyPayload, "payload should be unchanged")
+
+	r.RenderHostmaps("Final hostmaps", routerControl, senderControl)
+
+	// Also verify normal IPv6 VPN traffic still works between the nodes
+	t.Log("Verify normal IPv6 VPN tunnel still works")
+	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
+
+	routerControl.Stop()
+	senderControl.Stop()
+}
+
+func TestSNAT_MultipleFlows(t *testing.T) {
+	// Test that multiple distinct IPv4 flows from the same IPv6-only peer
+	// are tracked independently through SNAT.
+
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	unsafePrefix := "192.168.0.0/16"
+	snatAddr := netip.MustParseAddr("169.254.42.42")
+
+	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
+		cert.Version2, ca, caKey, "router", "ff::1/64",
+		netip.MustParseAddrPort("[beef::1]:4242"),
+		unsafePrefix,
+		m{
+			"firewall": m{
+				"inbound": []m{{
+					"proto":      "any",
+					"port":       "any",
+					"host":       "any",
+					"local_cidr": "any",
+				}},
+			},
+			"tun": m{
+				"snat_address_for_4over6": snatAddr.String(),
+			},
+		},
+	)
+
+	senderControl, _, _, _ := newSimpleServerWithUdp(
+		cert.Version2, ca, caKey, "sender", "ff::2/64",
+		netip.MustParseAddrPort("[beef::2]:4242"),
+		m{
+			"tun": m{
+				"unsafe_routes": []m{
+					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
+				},
+			},
+		},
+	)
+
+	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
+
+	r := router.NewR(t, routerControl, senderControl)
+	defer r.RenderFlow()
+	r.CancelFlowLogs()
+
+	routerControl.Start()
+	senderControl.Start()
+
+	unsafeDest := netip.MustParseAddr("192.168.1.1")
+
+	// Send first flow
+	senderControl.InjectTunUDPPacket(unsafeDest, 80, netip.MustParseAddr("10.0.0.1"), 1111, []byte("flow1"))
+	pkt1 := r.RouteForAllUntilTxTun(routerControl)
+	srcIP1, _, srcPort1, _, payload1 := parseIPv4UDPPacket(t, pkt1)
+	assert.Equal(t, snatAddr, srcIP1)
+	assert.Equal(t, []byte("flow1"), payload1)
+
+	// Send second flow (different source port)
+	senderControl.InjectTunUDPPacket(unsafeDest, 80, netip.MustParseAddr("10.0.0.1"), 2222, []byte("flow2"))
+	pkt2 := r.RouteForAllUntilTxTun(routerControl)
+	srcIP2, _, srcPort2, _, payload2 := parseIPv4UDPPacket(t, pkt2)
+	assert.Equal(t, snatAddr, srcIP2)
+	assert.Equal(t, []byte("flow2"), payload2)
+
+	// The two flows should have different SNAT ports (since they're different conntracks)
+	t.Logf("Flow 1 SNAT port: %d, Flow 2 SNAT port: %d", srcPort1, srcPort2)
+
+	// Reply to flow 2 first (out of order)
+	routerControl.InjectTunUDPPacket(snatAddr, srcPort2, unsafeDest, 80, []byte("reply2"))
+	reply2 := r.RouteForAllUntilTxTun(senderControl)
+	_, replyDst2, _, replyDstPort2, replyPayload2 := parseIPv4UDPPacket(t, reply2)
+	assert.Equal(t, netip.MustParseAddr("10.0.0.1"), replyDst2)
+	assert.Equal(t, uint16(2222), replyDstPort2, "reply to flow 2 should restore original port 2222")
+	assert.Equal(t, []byte("reply2"), replyPayload2)
+
+	// Reply to flow 1
+	routerControl.InjectTunUDPPacket(snatAddr, srcPort1, unsafeDest, 80, []byte("reply1"))
+	reply1 := r.RouteForAllUntilTxTun(senderControl)
+	_, replyDst1, _, replyDstPort1, replyPayload1 := parseIPv4UDPPacket(t, reply1)
+	assert.Equal(t, netip.MustParseAddr("10.0.0.1"), replyDst1)
+	assert.Equal(t, uint16(1111), replyDstPort1, "reply to flow 1 should restore original port 1111")
+	assert.Equal(t, []byte("reply1"), replyPayload1)
+
+	routerControl.Stop()
+	senderControl.Stop()
+}
+
+// --- Adversarial SNAT E2E Tests ---
+
+func TestSNAT_UnsolicitedReplyDropped(t *testing.T) {
+	// Without any outbound SNAT traffic, inject a packet from the router's TUN
+	// addressed to the SNAT address. The sender must never receive it because
+	// there's no conntrack entry to un-SNAT through.
+
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	unsafePrefix := "192.168.0.0/16"
+	snatAddr := netip.MustParseAddr("169.254.42.42")
+
+	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
+		cert.Version2, ca, caKey, "router", "ff::1/64",
+		netip.MustParseAddrPort("[beef::1]:4242"),
+		unsafePrefix,
+		m{
+			"firewall": m{
+				"inbound": []m{{
+					"proto":      "any",
+					"port":       "any",
+					"host":       "any",
+					"local_cidr": "any",
+				}},
+			},
+			"tun": m{
+				"snat_address_for_4over6": snatAddr.String(),
+			},
+		},
+	)
+
+	senderControl, _, _, _ := newSimpleServerWithUdp(
+		cert.Version2, ca, caKey, "sender", "ff::2/64",
+		netip.MustParseAddrPort("[beef::2]:4242"),
+		m{
+			"tun": m{
+				"unsafe_routes": []m{
+					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
+				},
+			},
+		},
+	)
+
+	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
+
+	r := router.NewR(t, routerControl, senderControl)
+	defer r.RenderFlow()
+	r.CancelFlowLogs()
+
+	routerControl.Start()
+	senderControl.Start()
+
+	// First establish the tunnel with normal IPv6 traffic so handshake completes
+	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
+
+	// Inject the unsolicited reply from router's TUN to the SNAT address.
+	// There is NO prior outbound SNAT flow, so no conntrack entry exists.
+	// The router should silently drop this because unSnat finds no matching conntrack.
+	routerControl.InjectTunUDPPacket(snatAddr, 55555, netip.MustParseAddr("192.168.1.1"), 80, []byte("unsolicited"))
+
+	// Send a canary IPv6 VPN packet after the bad one. Since the router processes
+	// TUN packets sequentially, the canary arriving proves the bad packet was processed first.
+	senderVpnAddr := senderControl.GetVpnAddrs()[0]
+	routerControl.InjectTunUDPPacket(senderVpnAddr, 90, routerVpnIpNet[0].Addr(), 80, []byte("canary"))
+	canaryPkt := r.RouteForAllUntilTxTun(senderControl)
+	assertUdpPacket(t, []byte("canary"), canaryPkt, routerVpnIpNet[0].Addr(), senderVpnAddr, 80, 90)
+
+	// The unsolicited packet should have been dropped — nothing else on sender's TUN
+	got := senderControl.GetFromTun(false)
+	assert.Nil(t, got, "sender should not receive unsolicited packet to SNAT address with no conntrack entry")
+
+	routerControl.Stop()
+	senderControl.Stop()
+}
+
+func TestSNAT_NonUnsafeDestDropped(t *testing.T) {
+	// An IPv6-only sender sends IPv4 traffic to a destination outside the router's
+	// unsafe networks (172.16.0.1 when unsafe is 192.168.0.0/16). The router should
+	// reject this because the local address is not routable. This verifies that
+	// willingToHandleLocalAddr enforces boundaries on what SNAT traffic can reach.
+
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	unsafePrefix := "192.168.0.0/16"
+	snatAddr := netip.MustParseAddr("169.254.42.42")
+
+	routerControl, routerVpnIpNet, routerUdpAddr, _ := newSimpleServerWithUdpAndUnsafeNetworks(
+		cert.Version2, ca, caKey, "router", "ff::1/64",
+		netip.MustParseAddrPort("[beef::1]:4242"),
+		unsafePrefix,
+		m{
+			"firewall": m{
+				"inbound": []m{{
+					"proto":      "any",
+					"port":       "any",
+					"host":       "any",
+					"local_cidr": "any",
+				}},
+			},
+			"tun": m{
+				"snat_address_for_4over6": snatAddr.String(),
+			},
+		},
+	)
+
+	// Sender has unsafe routes for BOTH 192.168.0.0/16 AND 172.16.0.0/12 via router.
+	// This means the sender will route 172.16.0.1 through the tunnel to the router.
+	// But the router should reject it because 172.16.0.0/12 is NOT in its unsafe networks.
+	senderControl, _, _, _ := newSimpleServerWithUdp(
+		cert.Version2, ca, caKey, "sender", "ff::2/64",
+		netip.MustParseAddrPort("[beef::2]:4242"),
+		m{
+			"tun": m{
+				"unsafe_routes": []m{
+					{"route": unsafePrefix, "via": routerVpnIpNet[0].Addr().String()},
+					{"route": "172.16.0.0/12", "via": routerVpnIpNet[0].Addr().String()},
+				},
+			},
+		},
+	)
+
+	senderControl.InjectLightHouseAddr(routerVpnIpNet[0].Addr(), routerUdpAddr)
+
+	r := router.NewR(t, routerControl, senderControl)
+	defer r.RenderFlow()
+	r.CancelFlowLogs()
+
+	routerControl.Start()
+	senderControl.Start()
+
+	// Establish the tunnel first
+	assertTunnel(t, routerVpnIpNet[0].Addr(), senderControl.GetVpnAddrs()[0], routerControl, senderControl, r)
+
+	// Send to 172.16.0.1 (NOT in router's unsafe networks 192.168.0.0/16).
+	// The router should reject this at willingToHandleLocalAddr.
+	senderControl.InjectTunUDPPacket(
+		netip.MustParseAddr("172.16.0.1"), 80,
+		netip.MustParseAddr("10.0.0.1"), 12345,
+		[]byte("wrong dest"),
+	)
+
+	// Send a canary to a valid unsafe destination to prove the bad packet was processed
+	senderControl.InjectTunUDPPacket(
+		netip.MustParseAddr("192.168.1.1"), 80,
+		netip.MustParseAddr("10.0.0.1"), 33333,
+		[]byte("canary"),
+	)
+
+	// Route until the canary arrives — the 172.16.0.1 packet should have been
+	// processed and dropped before the canary gets through
+	canaryPkt := r.RouteForAllUntilTxTun(routerControl)
+	_, canaryDst, _, _, canaryPayload := parseIPv4UDPPacket(t, canaryPkt)
+	assert.Equal(t, netip.MustParseAddr("192.168.1.1"), canaryDst, "canary should arrive at the valid unsafe dest")
+	assert.Equal(t, []byte("canary"), canaryPayload)
+
+	// No more packets — the 172.16.0.1 packet was dropped
+	got := routerControl.GetFromTun(false)
+	assert.Nil(t, got, "packet to non-unsafe destination 172.16.0.1 should be dropped by the router")
+
+	routerControl.Stop()
+	senderControl.Stop()
+}

e2e/tunnels_test.go

@@ -0,0 +1,367 @@
+//go:build e2e_testing
+// +build e2e_testing
+
+package e2e
+
+import (
+	"fmt"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/slackhq/nebula/cert"
+	"github.com/slackhq/nebula/cert_test"
+	"github.com/slackhq/nebula/e2e/router"
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v3"
+)
+
+func TestDropInactiveTunnels(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", m{"tunnels": m{"drop_inactive": true, "inactivity_timeout": "5s"}})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "them", "10.128.0.2/24", m{"tunnels": m{"drop_inactive": true, "inactivity_timeout": "10m"}})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+
+	r.Log("Assert the tunnel between me and them works")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+
+	r.Log("Go inactive and wait for the tunnels to get dropped")
+	waitStart := time.Now()
+	for {
+		myIndexes := len(myControl.GetHostmap().Indexes)
+		theirIndexes := len(theirControl.GetHostmap().Indexes)
+		if myIndexes == 0 && theirIndexes == 0 {
+			break
+		}
+
+		since := time.Since(waitStart)
+		r.Logf("my tunnels: %v; their tunnels: %v; duration: %v", myIndexes, theirIndexes, since)
+		if since > time.Second*30 {
+			t.Fatal("Tunnel should have been declared inactive after 5 seconds and before 30 seconds")
+		}
+
+		time.Sleep(1 * time.Second)
+		r.FlushAll()
+	}
+
+	r.Logf("Inactive tunnels were dropped within %v", time.Since(waitStart))
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCertUpgrade(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	caB, err := ca.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	ca2B, err := ca2.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
+
+	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	_, myCert2Pem := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": string(myCert2Pem),
+			"key":  string(myPrivKey),
+		},
+		//"tun": m{"disabled": true},
+		"firewall": myC.Settings["firewall"],
+		//"handshakes": m{
+		//	"try_interval": "1s",
+		//},
+		"listen":  myC.Settings["listen"],
+		"logging": myC.Settings["logging"],
+		"timers":  myC.Settings["timers"],
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	r.Logf("reload new v2-only config")
+	err = myC.ReloadConfigString(string(cb))
+	assert.NoError(t, err)
+	r.Log("yay, spin until their sees it")
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		if c == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			r.Logf("version %d", version)
+			if version == cert.Version2 {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*10 {
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCertDowngrade(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	caB, err := ca.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	ca2B, err := ca2.MarshalPEM()
+	if err != nil {
+		panic(err)
+	}
+	caStr := fmt.Sprintf("%s\n%s", caB, ca2B)
+
+	myCert, _, myPrivKey, myCertPem := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, myC := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
+	//r.Log("yay")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	mc := m{
+		"pki": m{
+			"ca":   caStr,
+			"cert": string(myCertPem),
+			"key":  string(myPrivKey),
+		},
+		"firewall": myC.Settings["firewall"],
+		"listen":   myC.Settings["listen"],
+		"logging":  myC.Settings["logging"],
+		"timers":   myC.Settings["timers"],
+	}
+
+	cb, err := yaml.Marshal(mc)
+	if err != nil {
+		panic(err)
+	}
+
+	r.Logf("reload new v1-only config")
+	err = myC.ReloadConfigString(string(cb))
+	assert.NoError(t, err)
+	r.Log("yay, spin until their sees it")
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+		if c == nil || c2 == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			theirVersion := c2.Cert.Version()
+			r.Logf("version %d,%d", version, theirVersion)
+			if version == cert.Version1 {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*5 {
+			r.Log("it is unusual that the cert is not new yet, but not a failure yet")
+		}
+		if since > time.Second*10 {
+			r.Log("wtf")
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCertMismatchCorrection(t *testing.T) {
+	// The goal of this test is to ensure the shortest inactivity timeout will close the tunnel on both sides
+	// under ideal conditions
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	ca2, _, caKey2, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	myCert, _, myPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "me", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.1/24")}, nil, []string{})
+	myCert2, _ := cert_test.NewTestCertDifferentVersion(myCert, cert.Version2, ca2, caKey2)
+
+	theirCert, _, theirPrivKey, _ := cert_test.NewTestCert(cert.Version1, cert.Curve_CURVE25519, ca, caKey, "them", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{netip.MustParsePrefix("10.128.0.2/24")}, nil, []string{})
+	theirCert2, _ := cert_test.NewTestCertDifferentVersion(theirCert, cert.Version2, ca2, caKey2)
+
+	myControl, myVpnIpNet, myUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{myCert2}, myPrivKey, m{})
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newServer([]cert.Certificate{ca, ca2}, []cert.Certificate{theirCert, theirCert2}, theirPrivKey, m{})
+
+	// Share our underlay information
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	// Start the servers
+	myControl.Start()
+	theirControl.Start()
+
+	r := router.NewR(t, myControl, theirControl)
+	defer r.RenderFlow()
+
+	r.Log("Assert the tunnel between me and them works")
+	//assertTunnel(t, theirVpnIpNet[0].Addr(), myVpnIpNet[0].Addr(), theirControl, myControl, r)
+	//r.Log("yay")
+	assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+	r.Log("yay")
+	//todo ???
+	time.Sleep(1 * time.Second)
+	r.FlushAll()
+
+	waitStart := time.Now()
+	for {
+		assertTunnel(t, myVpnIpNet[0].Addr(), theirVpnIpNet[0].Addr(), myControl, theirControl, r)
+		c := theirControl.GetHostInfoByVpnAddr(myVpnIpNet[0].Addr(), false)
+		c2 := myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false)
+		if c == nil || c2 == nil {
+			r.Log("nil")
+		} else {
+			version := c.Cert.Version()
+			theirVersion := c2.Cert.Version()
+			r.Logf("version %d,%d", version, theirVersion)
+			if version == theirVersion {
+				break
+			}
+		}
+		since := time.Since(waitStart)
+		if since > time.Second*5 {
+			r.Log("wtf")
+		}
+		if since > time.Second*10 {
+			r.Log("wtf")
+			t.Fatal("Cert should be new by now")
+		}
+		time.Sleep(time.Second)
+	}
+
+	r.RenderHostmaps("Final hostmaps", myControl, theirControl)
+
+	myControl.Stop()
+	theirControl.Stop()
+}
+
+func TestCrossStackRelaysWork(t *testing.T) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+	myControl, myVpnIpNet, _, _ := newSimpleServer(cert.Version2, ca, caKey, "me     ", "10.128.0.1/24,fc00::1/64", m{"relay": m{"use_relays": true}})
+	relayControl, relayVpnIpNet, relayUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "relay  ", "10.128.0.128/24,fc00::128/64", m{"relay": m{"am_relay": true}})
+	theirUdp := netip.MustParseAddrPort("10.0.0.2:4242")
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServerWithUdp(cert.Version2, ca, caKey, "them   ", "fc00::2/64", theirUdp, m{"relay": m{"use_relays": true}})
+
+	//myVpnV4 := myVpnIpNet[0]
+	myVpnV6 := myVpnIpNet[1]
+	relayVpnV4 := relayVpnIpNet[0]
+	relayVpnV6 := relayVpnIpNet[1]
+	theirVpnV6 := theirVpnIpNet[0]
+
+	// Teach my how to get to the relay and that their can be reached via the relay
+	myControl.InjectLightHouseAddr(relayVpnV4.Addr(), relayUdpAddr)
+	myControl.InjectLightHouseAddr(relayVpnV6.Addr(), relayUdpAddr)
+	myControl.InjectRelays(theirVpnV6.Addr(), []netip.Addr{relayVpnV6.Addr()})
+	relayControl.InjectLightHouseAddr(theirVpnV6.Addr(), theirUdpAddr)
+
+	// Build a router so we don't have to reason who gets which packet
+	r := router.NewR(t, myControl, relayControl, theirControl)
+	defer r.RenderFlow()
+
+	// Start the servers
+	myControl.Start()
+	relayControl.Start()
+	theirControl.Start()
+
+	t.Log("Trigger a handshake from me to them via the relay")
+	myControl.InjectTunUDPPacket(theirVpnV6.Addr(), 80, myVpnV6.Addr(), 80, []byte("Hi from me"))
+
+	p := r.RouteForAllUntilTxTun(theirControl)
+	r.Log("Assert the tunnel works")
+	assertUdpPacket(t, []byte("Hi from me"), p, myVpnV6.Addr(), theirVpnV6.Addr(), 80, 80)
+
+	t.Log("reply?")
+	theirControl.InjectTunUDPPacket(myVpnV6.Addr(), 80, theirVpnV6.Addr(), 80, []byte("Hi from them"))
+	p = r.RouteForAllUntilTxTun(myControl)
+	assertUdpPacket(t, []byte("Hi from them"), p, theirVpnV6.Addr(), myVpnV6.Addr(), 80, 80)
+
+	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
+	//t.Log("finish up")
+	//myControl.Stop()
+	//theirControl.Stop()
+	//relayControl.Stop()
+}

examples/config.yml

@@ -144,6 +144,10 @@ listen:
   # valid values: always, never, private
   # This setting is reloadable.
   #send_recv_error: always
+  # Similar to send_recv_error, this option lets you configure if you want to accept "recv_error" packets from remote hosts.
+  # valid values: always, never, private
+  # This setting is reloadable.
+  #accept_recv_error: always
   # The so_sock option is a Linux-specific feature that allows all outgoing Nebula packets to be tagged with a specific identifier.
   # This tagging enables IP rule-based filtering. For example, it supports 0.0.0.0/0 unsafe_routes,
   # allowing for more precise routing decisions based on the packet tags. Default is 0 meaning no mark is set.
@@ -279,6 +283,15 @@ tun:
   # If using massive routes updates, for example BGP, you may need to increase this value to avoid packet loss.
   # SO_RCVBUFFORCE is used to avoid having to raise the system wide max
   #use_system_route_table_buffer_size: 0
+  #
+  # When using the feature to carry IPv4 unsafe_routes through a IPv6-only overlay network (4over6),
+  # the system still needs to use IPv4 addresses to pass that traffic. 
+  # By default, they are randomly chosen out of 169.254.0.0/16 at startup, but if you need them to be static, you can set them here.
+  # Setting these options is not required for use of the 4over6 feature.
+  # this is the address that a client will use as a source IP for packets sent to the router
+  #unsafe_origin_address_for_4over6: 169.254.55.96
+  # this is the IP the router will use internally to hairpin-NAT 4over6 traffic before it hits the operating system.
+  #snat_address_for_4over6: 169.254.12.34
 
 # Configure logging level
 logging:
@@ -338,6 +351,18 @@ logging:
   # after receiving the response for lighthouse queries
   #trigger_buffer: 64
 
+# Tunnel manager settings
+#tunnels:
+  # drop_inactive controls whether inactive tunnels are maintained or dropped after the inactive_timeout period has
+  # elapsed.
+  # In general, it is a good idea to enable this setting. It will be enabled by default in a future release.
+  # This setting is reloadable
+  #drop_inactive: false
+
+  # inactivity_timeout controls how long a tunnel MUST NOT see any inbound or outbound traffic before being considered
+  # inactive and eligible to be dropped.
+  # This setting is reloadable
+  #inactivity_timeout: 10m
 
 # Nebula security group configuration
 firewall:
@@ -366,13 +391,14 @@ firewall:
   # Rules are comprised of a protocol, port, and one or more of host, group, or CIDR
   # Logical evaluation is roughly: port AND proto AND (ca_sha OR ca_name) AND (host OR group OR groups OR cidr) AND (local cidr)
   # - port: Takes `0` or `any` as any, a single number `80`, a range `200-901`, or `fragment` to match second and further fragments of fragmented packets (since there is no port available).
-  #   code: same as port but makes more sense when talking about ICMP, TODO: this is not currently implemented in a way that works, use `any`
   #   proto: `any`, `tcp`, `udp`, or `icmp`
+  #          a port specification is ignored if proto is `icmp`
   #   host: `any` or a literal hostname, ie `test-host`
   #   group: `any` or a literal group name, ie `default-group`
   #   groups: Same as group but accepts a list of values. Multiple values are AND'd together and a certificate would have to contain all groups to pass
-  #   cidr: a remote CIDR, `0.0.0.0/0` is any ipv4 and `::/0` is any ipv6.
+  #   cidr: a remote CIDR, `0.0.0.0/0` is any ipv4 and `::/0` is any ipv6. `any` means any ip family and address.
-  #   local_cidr: a local CIDR, `0.0.0.0/0` is any ipv4 and `::/0` is any ipv6. This can be used to filter destinations when using unsafe_routes.
+  #   local_cidr: a local CIDR, `0.0.0.0/0` is any ipv4 and `::/0` is any ipv6. `any` means any ip family and address.
+  #     This can be used to filter destinations when using unsafe_routes.
   #     By default, this is set to only the VPN (overlay) networks assigned via the certificate networks field unless `default_local_cidr_any` is set to true.
   #     If there are unsafe_routes present in this config file, `local_cidr` should be set appropriately for the intended us case.
   #   ca_name: An issuing CA name

firewall.go

@@ -2,12 +2,14 @@ package nebula
 
 import (
 	"crypto/sha256"
+	"encoding/binary"
 	"encoding/hex"
 	"errors"
 	"fmt"
 	"hash/fnv"
 	"net/netip"
 	"reflect"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -21,8 +23,33 @@ import (
 	"github.com/slackhq/nebula/firewall"
 )
 
+var ErrCannotSNAT = errors.New("cannot SNAT this packet")
+var ErrSNATIdentityMismatch = errors.New("refusing to SNAT for mismatched host")
+var ErrSNATAddressCollision = errors.New("refusing to accept an incoming packet with my SNAT address")
+
+const ipv4SourcePosition = 12
+const ipv4DestinationPosition = 16
+const sourcePortOffset = 0
+const destinationPortOffset = 2
+
 type FirewallInterface interface {
-	AddRule(incoming bool, proto uint8, startPort int32, endPort int32, groups []string, host string, addr, localAddr netip.Prefix, caName string, caSha string) error
+	AddRule(incoming bool, proto uint8, startPort int32, endPort int32, groups []string, host string, cidr, localCidr string, caName string, caSha string) error
+}
+
+type snatInfo struct {
+	//Src is the source IP+port to write into unsafe-route-bound packet
+	Src netip.AddrPort
+	//SrcVpnIp is the overlay IP associated with this flow. It's needed to associate reply traffic so we can get it back to the right host.
+	SrcVpnIp netip.Addr
+	//SnatPort is the port to rewrite into an overlay-bound packet
+	SnatPort uint16
+}
+
+func (s *snatInfo) Valid() bool {
+	if s == nil {
+		return false
+	}
+	return s.Src.IsValid()
 }
 
 type conn struct {
@@ -33,6 +60,9 @@ type conn struct {
 	// fields pack for free after the uint32 above
 	incoming     bool
 	rulesVersion uint16
+
+	//for SNAT support
+	snat *snatInfo
 }
 
 // TODO: need conntrack max tracked connections handling
@@ -65,6 +95,8 @@ type Firewall struct {
 	defaultLocalCIDRAny bool
 	incomingMetrics     firewallMetrics
 	outgoingMetrics     firewallMetrics
+	unsafeIPv4Origin    netip.Addr
+	snatAddr            netip.Addr
 
 	l *logrus.Logger
 }
@@ -192,12 +224,12 @@ func NewFirewall(l *logrus.Logger, tcpTimeout, UDPTimeout, defaultTimeout time.D
 
 func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firewall, error) {
 	certificate := cs.getCertificate(cert.Version2)
-	if certificate == nil {
+	if certificate == nil { //todo if config.initiating_version is set to 1, and unsafe_networks differ, things will suck
 		certificate = cs.getCertificate(cert.Version1)
 	}
 
 	if certificate == nil {
-		panic("No certificate available to reconfigure the firewall")
+		return nil, errors.New("no certificate available to reconfigure the firewall")
 	}
 
 	fw := NewFirewall(
@@ -206,7 +238,6 @@ func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firew
 		c.GetDuration("firewall.conntrack.udp_timeout", time.Minute*3),
 		c.GetDuration("firewall.conntrack.default_timeout", time.Minute*10),
 		certificate,
-		//TODO: max_connections
 	)
 
 	fw.defaultLocalCIDRAny = c.GetBool("firewall.default_local_cidr_any", false)
@@ -247,32 +278,7 @@ func NewFirewallFromConfig(l *logrus.Logger, cs *CertState, c *config.C) (*Firew
 }
 
 // AddRule properly creates the in memory rule structure for a firewall table.
-func (f *Firewall) AddRule(incoming bool, proto uint8, startPort int32, endPort int32, groups []string, host string, ip, localIp netip.Prefix, caName string, caSha string) error {
+func (f *Firewall) AddRule(incoming bool, proto uint8, startPort int32, endPort int32, groups []string, host string, cidr, localCidr, caName string, caSha string) error {
-	// Under gomobile, stringing a nil pointer with fmt causes an abort in debug mode for iOS
-	// https://github.com/golang/go/issues/14131
-	sIp := ""
-	if ip.IsValid() {
-		sIp = ip.String()
-	}
-	lIp := ""
-	if localIp.IsValid() {
-		lIp = localIp.String()
-	}
-
-	// We need this rule string because we generate a hash. Removing this will break firewall reload.
-	ruleString := fmt.Sprintf(
-		"incoming: %v, proto: %v, startPort: %v, endPort: %v, groups: %v, host: %v, ip: %v, localIp: %v, caName: %v, caSha: %s",
-		incoming, proto, startPort, endPort, groups, host, sIp, lIp, caName, caSha,
-	)
-	f.rules += ruleString + "\n"
-
-	direction := "incoming"
-	if !incoming {
-		direction = "outgoing"
-	}
-	f.l.WithField("firewallRule", m{"direction": direction, "proto": proto, "startPort": startPort, "endPort": endPort, "groups": groups, "host": host, "ip": sIp, "localIp": lIp, "caName": caName, "caSha": caSha}).
-		Info("Firewall rule added")
-
 	var (
 		ft *FirewallTable
 		fp firewallPort
@@ -290,6 +296,12 @@ func (f *Firewall) AddRule(incoming bool, proto uint8, startPort int32, endPort
 	case firewall.ProtoUDP:
 		fp = ft.UDP
 	case firewall.ProtoICMP, firewall.ProtoICMPv6:
+		//ICMP traffic doesn't have ports, so we always coerce to "any", even if a value is provided
+		if startPort != firewall.PortAny {
+			f.l.WithField("startPort", startPort).Warn("ignoring port specification for ICMP firewall rule")
+		}
+		startPort = firewall.PortAny
+		endPort = firewall.PortAny
 		fp = ft.ICMP
 	case firewall.ProtoAny:
 		fp = ft.AnyProto
@@ -297,7 +309,21 @@ func (f *Firewall) AddRule(incoming bool, proto uint8, startPort int32, endPort
 		return fmt.Errorf("unknown protocol %v", proto)
 	}
 
-	return fp.addRule(f, startPort, endPort, groups, host, ip, localIp, caName, caSha)
+	// We need this rule string because we generate a hash. Removing this will break firewall reload.
+	ruleString := fmt.Sprintf(
+		"incoming: %v, proto: %v, startPort: %v, endPort: %v, groups: %v, host: %v, ip: %v, localIp: %v, caName: %v, caSha: %s",
+		incoming, proto, startPort, endPort, groups, host, cidr, localCidr, caName, caSha,
+	)
+	f.rules += ruleString + "\n"
+
+	direction := "incoming"
+	if !incoming {
+		direction = "outgoing"
+	}
+	f.l.WithField("firewallRule", m{"direction": direction, "proto": proto, "startPort": startPort, "endPort": endPort, "groups": groups, "host": host, "cidr": cidr, "localCidr": localCidr, "caName": caName, "caSha": caSha}).
+		Info("Firewall rule added")
+
+	return fp.addRule(f, startPort, endPort, groups, host, cidr, localCidr, caName, caSha)
 }
 
 // GetRuleHash returns a hash representation of all inbound and outbound rules
@@ -318,6 +344,18 @@ func (f *Firewall) GetRuleHashes() string {
 	return "SHA:" + f.GetRuleHash() + ",FNV:" + strconv.FormatUint(uint64(f.GetRuleHashFNV()), 10)
 }
 
+func (f *Firewall) SetSNATAddressFromInterface(i *Interface) {
+	//address-mutation-avoidance is done inside Interface, the firewall doesn't need to care
+	//todo should snatted conntracks get expired out? Probably not needed until if/when we allow reload
+	f.snatAddr = i.inside.SNATAddress().Addr()
+	f.unsafeIPv4Origin = i.inside.UnsafeIPv4OriginAddress().Addr()
+}
+
+func (f *Firewall) ShouldUnSNAT(fp *firewall.Packet) bool {
+	// f.snatAddr is only valid if we're a snat-capable router
+	return f.snatAddr.IsValid() && fp.RemoteAddr == f.snatAddr
+}
+
 func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw FirewallInterface) error {
 	var table string
 	if inbound {
@@ -337,7 +375,6 @@ func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw
 	}
 
 	for i, t := range rs {
-		var groups []string
 		r, err := convertRule(l, t, table, i)
 		if err != nil {
 			return fmt.Errorf("%s rule #%v; %s", table, i, err)
@@ -347,23 +384,10 @@ func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw
 			return fmt.Errorf("%s rule #%v; only one of port or code should be provided", table, i)
 		}
 
-		if r.Host == "" && len(r.Groups) == 0 && r.Group == "" && r.Cidr == "" && r.LocalCidr == "" && r.CAName == "" && r.CASha == "" {
+		if r.Host == "" && len(r.Groups) == 0 && r.Cidr == "" && r.LocalCidr == "" && r.CAName == "" && r.CASha == "" {
 			return fmt.Errorf("%s rule #%v; at least one of host, group, cidr, local_cidr, ca_name, or ca_sha must be provided", table, i)
 		}
 
-		if len(r.Groups) > 0 {
-			groups = r.Groups
-		}
-
-		if r.Group != "" {
-			// Check if we have both groups and group provided in the rule config
-			if len(groups) > 0 {
-				return fmt.Errorf("%s rule #%v; only one of group or groups should be defined, both provided", table, i)
-			}
-
-			groups = []string{r.Group}
-		}
-
 		var sPort, errPort string
 		if r.Code != "" {
 			errPort = "code"
@@ -373,42 +397,51 @@ func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw
 			sPort = r.Port
 		}
 
-		startPort, endPort, err := parsePort(sPort)
+		var proto uint8
+		var startPort, endPort int32
+		switch r.Proto {
+		case "any":
+			proto = firewall.ProtoAny
+			startPort, endPort, err = parsePort(sPort)
+		case "tcp":
+			proto = firewall.ProtoTCP
+			startPort, endPort, err = parsePort(sPort)
+		case "udp":
+			proto = firewall.ProtoUDP
+			startPort, endPort, err = parsePort(sPort)
+		case "icmp":
+			proto = firewall.ProtoICMP
+			startPort = firewall.PortAny
+			endPort = firewall.PortAny
+			if sPort != "" {
+				l.WithField("port", sPort).Warn("ignoring port specification for ICMP firewall rule")
+			}
+		default:
+			return fmt.Errorf("%s rule #%v; proto was not understood; `%s`", table, i, r.Proto)
+		}
 		if err != nil {
 			return fmt.Errorf("%s rule #%v; %s %s", table, i, errPort, err)
 		}
 
-		var proto uint8
+		if r.Cidr != "" && r.Cidr != "any" {
-		switch r.Proto {
+			_, err = netip.ParsePrefix(r.Cidr)
-		case "any":
-			proto = firewall.ProtoAny
-		case "tcp":
-			proto = firewall.ProtoTCP
-		case "udp":
-			proto = firewall.ProtoUDP
-		case "icmp":
-			proto = firewall.ProtoICMP
-		default:
-			return fmt.Errorf("%s rule #%v; proto was not understood; `%s`", table, i, r.Proto)
-		}
-
-		var cidr netip.Prefix
-		if r.Cidr != "" {
-			cidr, err = netip.ParsePrefix(r.Cidr)
 			if err != nil {
 				return fmt.Errorf("%s rule #%v; cidr did not parse; %s", table, i, err)
 			}
 		}
 
-		var localCidr netip.Prefix
+		if r.LocalCidr != "" && r.LocalCidr != "any" {
-		if r.LocalCidr != "" {
+			_, err = netip.ParsePrefix(r.LocalCidr)
-			localCidr, err = netip.ParsePrefix(r.LocalCidr)
 			if err != nil {
 				return fmt.Errorf("%s rule #%v; local_cidr did not parse; %s", table, i, err)
 			}
 		}
 
-		err = fw.AddRule(inbound, proto, startPort, endPort, groups, r.Host, cidr, localCidr, r.CAName, r.CASha)
+		if warning := r.sanity(); warning != nil {
+			l.Warnf("%s rule #%v; %s", table, i, warning)
+		}
+
+		err = fw.AddRule(inbound, proto, startPort, endPort, r.Groups, r.Host, r.Cidr, r.LocalCidr, r.CAName, r.CASha)
 		if err != nil {
 			return fmt.Errorf("%s rule #%v; `%s`", table, i, err)
 		}
@@ -417,43 +450,215 @@ func AddFirewallRulesFromConfig(l *logrus.Logger, inbound bool, c *config.C, fw
 	return nil
 }
 
-var ErrInvalidRemoteIP = errors.New("remote IP is not in remote certificate subnets")
+var ErrUnknownNetworkType = errors.New("unknown network type")
-var ErrInvalidLocalIP = errors.New("local IP is not in list of handled local IPs")
+var ErrPeerRejected = errors.New("remote address is not within a network that we handle")
+var ErrInvalidRemoteIP = errors.New("remote address is not in remote certificate networks")
+var ErrInvalidLocalIP = errors.New("local address is not in list of handled local addresses")
 var ErrNoMatchingRule = errors.New("no matching rule in firewall table")
 
-// Drop returns an error if the packet should be dropped, explaining why. It
+func (f *Firewall) unSnat(data []byte, fp *firewall.Packet) netip.Addr {
-// returns nil if the packet should not be dropped.
+	c := f.peek(*fp) //unfortunately this needs to lock. Surely there's a better way.
-func (f *Firewall) Drop(fp firewall.Packet, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) error {
+	if c == nil {
-	// Check if we spoke to this tuple, if we did then allow this packet
+		return netip.Addr{}
-	if f.inConns(fp, h, caPool, localCache) {
+	}
-		return nil
+	if !c.snat.Valid() {
+		return netip.Addr{}
+	}
+	oldIP := netip.AddrPortFrom(f.snatAddr, fp.RemotePort)
+	rewritePacket(data, fp, oldIP, c.snat.Src, ipv4DestinationPosition, destinationPortOffset)
+	return c.snat.SrcVpnIp
+}
+
+func rewritePacket(data []byte, fp *firewall.Packet, oldIP netip.AddrPort, newIP netip.AddrPort, ipOffset int, portOffset int) {
+	//change address
+	copy(data[ipOffset:], newIP.Addr().AsSlice())
+	recalcIPv4Checksum(data, oldIP.Addr(), newIP.Addr())
+	ipHeaderLen := int(data[0]&0x0F) * 4
+
+	switch fp.Protocol {
+	case firewall.ProtoICMP:
+		binary.BigEndian.PutUint16(data[ipHeaderLen+4:ipHeaderLen+6], newIP.Port()) //we use the ID field as a "port" for ICMP
+		icmpCode := uint16(data[ipHeaderLen+1])                                     //todo not snatting on code yet (but Linux would)
+		recalcICMPv4Checksum(data, icmpCode, icmpCode, oldIP.Port(), newIP.Port())
+	case firewall.ProtoUDP:
+		dstport := ipHeaderLen + portOffset
+		binary.BigEndian.PutUint16(data[dstport:dstport+2], newIP.Port())
+		recalcUDPv4Checksum(data, oldIP, newIP)
+	case firewall.ProtoTCP:
+		dstport := ipHeaderLen + portOffset
+		binary.BigEndian.PutUint16(data[dstport:dstport+2], newIP.Port())
+		recalcTCPv4Checksum(data, oldIP, newIP)
+	}
+}
+
+func (f *Firewall) findUsableSNATPort(fp *firewall.Packet, c *conn) error {
+	const halfThePorts = 0x7fff
+	oldPort := fp.RemotePort
+	conntrack := f.Conntrack
+	conntrack.Lock()
+	defer conntrack.Unlock()
+	for numPortsChecked := 0; numPortsChecked < halfThePorts; numPortsChecked++ {
+		_, ok := conntrack.Conns[*fp]
+		if !ok {
+			//yay, we can use this port
+			//track the snatted flow with the same expiration as the unsnatted version
+			c.snat.SnatPort = fp.RemotePort
+			conntrack.Conns[*fp] = c
+			return nil
+		}
+		//increment and retry. There's probably better strategies out there
+		fp.RemotePort++
+		if fp.RemotePort < halfThePorts {
+			fp.RemotePort += halfThePorts // keep it ephemeral for now
+		}
 	}
 
-	// Make sure remote address matches nebula certificate
+	//if we made it here, we failed
-	if h.networks != nil {
+	fp.RemotePort = oldPort
-		if !h.networks.Contains(fp.RemoteAddr) {
+	return ErrCannotSNAT
-			f.metrics(incoming).droppedRemoteAddr.Inc(1)
+}
-			return ErrInvalidRemoteIP
+
+func (f *Firewall) applySnat(data []byte, fp *firewall.Packet, c *conn, hostinfo *HostInfo) error {
+	if !f.snatAddr.IsValid() {
+		return ErrCannotSNAT
+	}
+	if f.snatAddr == fp.LocalAddr { //a packet that came from UDP (incoming) should never ever have our snat address on it
+		return ErrSNATAddressCollision
+	}
+	if c.snat.Valid() {
+		//old flow: make sure it came from the right place
+		if !slices.Contains(hostinfo.vpnAddrs, c.snat.SrcVpnIp) {
+			return ErrSNATIdentityMismatch
+		}
+		fp.RemoteAddr = f.snatAddr
+		fp.RemotePort = c.snat.SnatPort
+	} else if hostinfo.vpnAddrs[0].Is6() {
+		//we got a new flow
+		c.snat = &snatInfo{
+			Src:      netip.AddrPortFrom(fp.RemoteAddr, fp.RemotePort),
+			SrcVpnIp: hostinfo.vpnAddrs[0],
+		}
+		fp.RemoteAddr = f.snatAddr
+		//find a new port to use, if needed
+		err := f.findUsableSNATPort(fp, c)
+		if err != nil {
+			c.snat = nil
+			return err
 		}
 	} else {
-		// Simple case: Certificate has one address and no unsafe networks
+		return ErrCannotSNAT
-		if h.vpnAddrs[0] != fp.RemoteAddr {
-			f.metrics(incoming).droppedRemoteAddr.Inc(1)
-			return ErrInvalidRemoteIP
-		}
 	}
 
-	// Make sure we are supposed to be handling this local ip address
+	newIP := netip.AddrPortFrom(f.snatAddr, c.snat.SnatPort)
-	if !f.routableNetworks.Contains(fp.LocalAddr) {
+	rewritePacket(data, fp, c.snat.Src, newIP, ipv4SourcePosition, sourcePortOffset)
-		f.metrics(incoming).droppedLocalAddr.Inc(1)
+	return nil
+}
+
+func (f *Firewall) identifyRemoteNetworkType(h *HostInfo, fp firewall.Packet) NetworkType {
+	if h.networks == nil {
+		// Simple case: Certificate has one address and no unsafe networks
+		if h.vpnAddrs[0] == fp.RemoteAddr {
+			return NetworkTypeVPN
+		} //else, fallthrough
+	} else if nwType, ok := h.networks.Lookup(fp.RemoteAddr); ok {
+		return nwType //will return NetworkTypeVPN or NetworkTypeUnsafe
+	}
+
+	//RemoteAddr not in our networks table
+	if f.snatAddr.IsValid() && fp.IsIPv4() && h.HasOnlyV6Addresses() {
+		return NetworkTypeUnverifiedSNATPeer
+	} else {
+		return NetworkTypeInvalidPeer
+	}
+}
+
+func (f *Firewall) allowRemoteNetworkType(nwType NetworkType, fp firewall.Packet) error {
+	switch nwType {
+	case NetworkTypeVPN:
+		return nil
+	case NetworkTypeInvalidPeer:
+		return ErrInvalidRemoteIP
+	case NetworkTypeVPNPeer:
+		//one day we might need a specialSnatMode case in here to handle routers with v4 addresses when we don't also have a v4 address?
+		return ErrPeerRejected // reject for now, one day this may have different FW rules
+	case NetworkTypeUnsafe:
+		return nil // nothing special, one day this may have different FW rules
+	case NetworkTypeUnverifiedSNATPeer:
+		if f.unsafeIPv4Origin.IsValid() && fp.LocalAddr == f.unsafeIPv4Origin {
+			return nil //the client case
+		}
+		if f.snatAddr.IsValid() {
+			if fp.RemoteAddr == f.snatAddr {
+				return ErrInvalidRemoteIP //we should never get a packet with our SNAT addr as the destination, or "from" our SNAT addr
+			}
+			return nil
+		} else {
+			return ErrInvalidRemoteIP
+		}
+	default:
+		return ErrUnknownNetworkType //should never happen
+	}
+}
+
+func (f *Firewall) willingToHandleLocalAddr(incoming bool, fp firewall.Packet, remoteNwType NetworkType) error {
+	if f.routableNetworks.Contains(fp.LocalAddr) {
+		return nil //easy, this should handle NetworkTypeVPN in all cases, and NetworkTypeUnsafe on the router side
+	}
+	if incoming { //at least for now, reject all traffic other than what we've already decided is locally routable
 		return ErrInvalidLocalIP
 	}
 
+	//below this line, all traffic is outgoing. Outgoing traffic to NetworkTypeUnsafe is not required to be considered inbound-routable
+	if remoteNwType == NetworkTypeUnsafe {
+		return nil
+	}
+
+	return ErrInvalidLocalIP
+}
+
+// Drop returns an error if the packet should be dropped, explaining why. It
+// returns nil if the packet should not be dropped.
+func (f *Firewall) Drop(fp firewall.Packet, pkt []byte, incoming bool, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) error {
 	table := f.OutRules
 	if incoming {
 		table = f.InRules
 	}
 
+	snatmode := fp.IsIPv4() && h.HasOnlyV6Addresses() && f.snatAddr.IsValid()
+	if snatmode {
+		//if this is an IPv4 packet from a V6 only host, and we're configured to snat that kind of traffic, it must be snatted,
+		//so it can never be in the localcache, which lacks SNAT data
+		//nil out the pointer to avoid ever using it
+		localCache = nil
+	}
+
+	// Check if we spoke to this tuple, if we did then allow this packet
+	if localCache != nil {
+		if _, ok := localCache[fp]; ok {
+			return nil //packet matched the cache, we're not snatting, we can return early
+		}
+	}
+	c := f.inConns(fp, h, caPool, localCache)
+	if c != nil {
+		if incoming && snatmode {
+			return f.applySnat(pkt, &fp, c, h)
+		}
+		return nil
+	}
+
+	// Make sure remote address matches nebula certificate, and determine how to treat it
+	remoteNetworkType := f.identifyRemoteNetworkType(h, fp)
+	if err := f.allowRemoteNetworkType(remoteNetworkType, fp); err != nil {
+		f.metrics(incoming).droppedRemoteAddr.Inc(1)
+		return err
+	}
+
+	// Make sure we are supposed to be handling this local ip address
+	if err := f.willingToHandleLocalAddr(incoming, fp, remoteNetworkType); err != nil {
+		f.metrics(incoming).droppedLocalAddr.Inc(1)
+		return err
+	}
+
 	// We now know which firewall table to check against
 	if !table.match(fp, incoming, h.ConnectionState.peerCert, caPool) {
 		f.metrics(incoming).droppedNoRule.Inc(1)
@@ -461,9 +666,14 @@ func (f *Firewall) Drop(fp firewall.Packet, incoming bool, h *HostInfo, caPool *
 	}
 
 	// We always want to conntrack since it is a faster operation
-	f.addConn(fp, incoming)
+	c = f.addConn(fp, incoming)
 
-	return nil
+	if incoming && remoteNetworkType == NetworkTypeUnverifiedSNATPeer {
+		return f.applySnat(pkt, &fp, c, h)
+	} else {
+		//outgoing snat is handled before this function is called
+		return nil
+	}
 }
 
 func (f *Firewall) metrics(incoming bool) firewallMetrics {
@@ -474,7 +684,7 @@ func (f *Firewall) metrics(incoming bool) firewallMetrics {
 	}
 }
 
-// Destroy cleans up any known cyclical references so the object can be free'd my GC. This should be called if a new
+// Destroy cleans up any known cyclical references so the object can be freed by GC. This should be called if a new
 // firewall object is created
 func (f *Firewall) Destroy() {
 	//TODO: clean references if/when needed
@@ -490,12 +700,14 @@ func (f *Firewall) EmitStats() {
 	metrics.GetOrRegisterGauge("firewall.rules.hash", nil).Update(int64(f.GetRuleHashFNV()))
 }
 
-func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) bool {
+func (f *Firewall) peek(fp firewall.Packet) *conn {
-	if localCache != nil {
+	f.Conntrack.Lock()
-		if _, ok := localCache[fp]; ok {
+	c := f.Conntrack.Conns[fp]
-			return true
+	f.Conntrack.Unlock()
-		}
+	return c
-	}
+}
+
+func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool, localCache firewall.ConntrackCache) *conn {
 	conntrack := f.Conntrack
 	conntrack.Lock()
 
@@ -509,7 +721,7 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 
 	if !ok {
 		conntrack.Unlock()
-		return false
+		return nil
 	}
 
 	if c.rulesVersion != f.rulesVersion {
@@ -532,7 +744,7 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 			}
 			delete(conntrack.Conns, fp)
 			conntrack.Unlock()
-			return false
+			return nil
 		}
 
 		if f.l.Level >= logrus.DebugLevel {
@@ -562,12 +774,11 @@ func (f *Firewall) inConns(fp firewall.Packet, h *HostInfo, caPool *cert.CAPool,
 		localCache[fp] = struct{}{}
 	}
 
-	return true
+	return c
 }
 
-func (f *Firewall) addConn(fp firewall.Packet, incoming bool) {
+func (f *Firewall) packetTimeout(fp firewall.Packet) time.Duration {
 	var timeout time.Duration
-	c := &conn{}
 
 	switch fp.Protocol {
 	case firewall.ProtoTCP:
@@ -577,7 +788,13 @@ func (f *Firewall) addConn(fp firewall.Packet, incoming bool) {
 	default:
 		timeout = f.DefaultTimeout
 	}
+	return timeout
+}
 
+func (f *Firewall) addConn(fp firewall.Packet, incoming bool) *conn {
+	c := &conn{}
+
+	timeout := f.packetTimeout(fp)
 	conntrack := f.Conntrack
 	conntrack.Lock()
 	if _, ok := conntrack.Conns[fp]; !ok {
@@ -591,7 +808,9 @@ func (f *Firewall) addConn(fp firewall.Packet, incoming bool) {
 	c.rulesVersion = f.rulesVersion
 	c.Expires = time.Now().Add(timeout)
 	conntrack.Conns[fp] = c
+
 	conntrack.Unlock()
+	return c
 }
 
 // Evict checks if a conntrack entry has expired, if so it is removed, if not it is re-added to the wheel
@@ -640,7 +859,7 @@ func (ft *FirewallTable) match(p firewall.Packet, incoming bool, c *cert.CachedC
 	return false
 }
 
-func (fp firewallPort) addRule(f *Firewall, startPort int32, endPort int32, groups []string, host string, ip, localIp netip.Prefix, caName string, caSha string) error {
+func (fp firewallPort) addRule(f *Firewall, startPort int32, endPort int32, groups []string, host string, cidr, localCidr, caName string, caSha string) error {
 	if startPort > endPort {
 		return fmt.Errorf("start port was lower than end port")
 	}
@@ -653,7 +872,7 @@ func (fp firewallPort) addRule(f *Firewall, startPort int32, endPort int32, grou
 			}
 		}
 
-		if err := fp[i].addRule(f, groups, host, ip, localIp, caName, caSha); err != nil {
+		if err := fp[i].addRule(f, groups, host, cidr, localCidr, caName, caSha); err != nil {
 			return err
 		}
 	}
@@ -667,6 +886,13 @@ func (fp firewallPort) match(p firewall.Packet, incoming bool, c *cert.CachedCer
 		return false
 	}
 
+	// this branch is here to catch traffic from FirewallTable.Any.match and FirewallTable.ICMP.match
+	if p.Protocol == firewall.ProtoICMP || p.Protocol == firewall.ProtoICMPv6 {
+		// port numbers are re-used for connection tracking of ICMP,
+		// but we don't want to actually filter on them.
+		return fp[firewall.PortAny].match(p, c, caPool)
+	}
+
 	var port int32
 
 	if p.Fragment {
@@ -684,7 +910,7 @@ func (fp firewallPort) match(p firewall.Packet, incoming bool, c *cert.CachedCer
 	return fp[firewall.PortAny].match(p, c, caPool)
 }
 
-func (fc *FirewallCA) addRule(f *Firewall, groups []string, host string, ip, localIp netip.Prefix, caName, caSha string) error {
+func (fc *FirewallCA) addRule(f *Firewall, groups []string, host string, cidr, localCidr, caName, caSha string) error {
 	fr := func() *FirewallRule {
 		return &FirewallRule{
 			Hosts:  make(map[string]*firewallLocalCIDR),
@@ -698,14 +924,14 @@ func (fc *FirewallCA) addRule(f *Firewall, groups []string, host string, ip, loc
 			fc.Any = fr()
 		}
 
-		return fc.Any.addRule(f, groups, host, ip, localIp)
+		return fc.Any.addRule(f, groups, host, cidr, localCidr)
 	}
 
 	if caSha != "" {
 		if _, ok := fc.CAShas[caSha]; !ok {
 			fc.CAShas[caSha] = fr()
 		}
-		err := fc.CAShas[caSha].addRule(f, groups, host, ip, localIp)
+		err := fc.CAShas[caSha].addRule(f, groups, host, cidr, localCidr)
 		if err != nil {
 			return err
 		}
@@ -715,7 +941,7 @@ func (fc *FirewallCA) addRule(f *Firewall, groups []string, host string, ip, loc
 		if _, ok := fc.CANames[caName]; !ok {
 			fc.CANames[caName] = fr()
 		}
-		err := fc.CANames[caName].addRule(f, groups, host, ip, localIp)
+		err := fc.CANames[caName].addRule(f, groups, host, cidr, localCidr)
 		if err != nil {
 			return err
 		}
@@ -747,24 +973,24 @@ func (fc *FirewallCA) match(p firewall.Packet, c *cert.CachedCertificate, caPool
 	return fc.CANames[s.Certificate.Name()].match(p, c)
 }
 
-func (fr *FirewallRule) addRule(f *Firewall, groups []string, host string, ip, localCIDR netip.Prefix) error {
+func (fr *FirewallRule) addRule(f *Firewall, groups []string, host, cidr, localCidr string) error {
 	flc := func() *firewallLocalCIDR {
 		return &firewallLocalCIDR{
 			LocalCIDR: new(bart.Lite),
 		}
 	}
 
-	if fr.isAny(groups, host, ip) {
+	if fr.isAny(groups, host, cidr) {
 		if fr.Any == nil {
 			fr.Any = flc()
 		}
 
-		return fr.Any.addRule(f, localCIDR)
+		return fr.Any.addRule(f, localCidr)
 	}
 
 	if len(groups) > 0 {
 		nlc := flc()
-		err := nlc.addRule(f, localCIDR)
+		err := nlc.addRule(f, localCidr)
 		if err != nil {
 			return err
 		}
@@ -780,44 +1006,46 @@ func (fr *FirewallRule) addRule(f *Firewall, groups []string, host string, ip, l
 		if nlc == nil {
 			nlc = flc()
 		}
-		err := nlc.addRule(f, localCIDR)
+		err := nlc.addRule(f, localCidr)
 		if err != nil {
 			return err
 		}
 		fr.Hosts[host] = nlc
 	}
 
-	if ip.IsValid() {
+	if cidr != "" {
-		nlc, _ := fr.CIDR.Get(ip)
+		c, err := netip.ParsePrefix(cidr)
-		if nlc == nil {
-			nlc = flc()
-		}
-		err := nlc.addRule(f, localCIDR)
 		if err != nil {
 			return err
 		}
-		fr.CIDR.Insert(ip, nlc)
+		nlc, _ := fr.CIDR.Get(c)
+		if nlc == nil {
+			nlc = flc()
+		}
+		err = nlc.addRule(f, localCidr)
+		if err != nil {
+			return err
+		}
+		fr.CIDR.Insert(c, nlc)
 	}
 
 	return nil
 }
 
-func (fr *FirewallRule) isAny(groups []string, host string, ip netip.Prefix) bool {
+func (fr *FirewallRule) isAny(groups []string, host string, cidr string) bool {
-	if len(groups) == 0 && host == "" && !ip.IsValid() {
+	if len(groups) == 0 && host == "" && cidr == "" {
 		return true
 	}
 
-	for _, group := range groups {
+	if slices.Contains(groups, "any") {
-		if group == "any" {
+		return true
-			return true
-		}
 	}
 
 	if host == "any" {
 		return true
 	}
 
-	if ip.IsValid() && ip.Bits() == 0 {
+	if cidr == "any" {
 		return true
 	}
 
@@ -869,8 +1097,13 @@ func (fr *FirewallRule) match(p firewall.Packet, c *cert.CachedCertificate) bool
 	return false
 }
 
-func (flc *firewallLocalCIDR) addRule(f *Firewall, localIp netip.Prefix) error {
+func (flc *firewallLocalCIDR) addRule(f *Firewall, localCidr string) error {
-	if !localIp.IsValid() {
+	if localCidr == "any" {
+		flc.Any = true
+		return nil
+	}
+
+	if localCidr == "" {
 		if !f.hasUnsafeNetworks || f.defaultLocalCIDRAny {
 			flc.Any = true
 			return nil
@@ -881,12 +1114,13 @@ func (flc *firewallLocalCIDR) addRule(f *Firewall, localIp netip.Prefix) error {
 		}
 		return nil
 
-	} else if localIp.Bits() == 0 {
-		flc.Any = true
-		return nil
 	}
 
-	flc.LocalCIDR.Insert(localIp)
+	c, err := netip.ParsePrefix(localCidr)
+	if err != nil {
+		return err
+	}
+	flc.LocalCIDR.Insert(c)
 	return nil
 }
 
@@ -907,7 +1141,6 @@ type rule struct {
 	Code      string
 	Proto     string
 	Host      string
-	Group     string
 	Groups    []string
 	Cidr      string
 	LocalCidr string
@@ -949,7 +1182,8 @@ func convertRule(l *logrus.Logger, p any, table string, i int) (rule, error) {
 		l.Warnf("%s rule #%v; group was an array with a single value, converting to simple value", table, i)
 		m["group"] = v[0]
 	}
-	r.Group = toString("group", m)
+
+	singleGroup := toString("group", m)
 
 	if rg, ok := m["groups"]; ok {
 		switch reflect.TypeOf(rg).Kind() {
@@ -966,52 +1200,105 @@ func convertRule(l *logrus.Logger, p any, table string, i int) (rule, error) {
 		}
 	}
 
+	//flatten group vs groups
+	if singleGroup != "" {
+		// Check if we have both groups and group provided in the rule config
+		if len(r.Groups) > 0 {
+			return r, fmt.Errorf("only one of group or groups should be defined, both provided")
+		}
+		r.Groups = []string{singleGroup}
+	}
+
 	return r, nil
 }
 
-func parsePort(s string) (startPort, endPort int32, err error) {
+// sanity returns an error if the rule would be evaluated in a way that would short-circuit a configured check on a wildcard value
-	if s == "any" {
+// rules are evaluated as "port AND proto AND (ca_sha OR ca_name) AND (host OR group OR groups OR cidr) AND local_cidr"
-		startPort = firewall.PortAny
+func (r *rule) sanity() error {
-		endPort = firewall.PortAny
+	//port, proto, local_cidr are AND, no need to check here
+	//ca_sha and ca_name don't have a wildcard value, no need to check here
+	groupsEmpty := len(r.Groups) == 0
+	hostEmpty := r.Host == ""
+	cidrEmpty := r.Cidr == ""
 
-	} else if s == "fragment" {
+	if (groupsEmpty && hostEmpty && cidrEmpty) == true {
-		startPort = firewall.PortFragment
+		return nil //no content!
-		endPort = firewall.PortFragment
-
-	} else if strings.Contains(s, `-`) {
-		sPorts := strings.SplitN(s, `-`, 2)
-		sPorts[0] = strings.Trim(sPorts[0], " ")
-		sPorts[1] = strings.Trim(sPorts[1], " ")
-
-		if len(sPorts) != 2 || sPorts[0] == "" || sPorts[1] == "" {
-			return 0, 0, fmt.Errorf("appears to be a range but could not be parsed; `%s`", s)
-		}
-
-		rStartPort, err := strconv.Atoi(sPorts[0])
-		if err != nil {
-			return 0, 0, fmt.Errorf("beginning range was not a number; `%s`", sPorts[0])
-		}
-
-		rEndPort, err := strconv.Atoi(sPorts[1])
-		if err != nil {
-			return 0, 0, fmt.Errorf("ending range was not a number; `%s`", sPorts[1])
-		}
-
-		startPort = int32(rStartPort)
-		endPort = int32(rEndPort)
-
-		if startPort == firewall.PortAny {
-			endPort = firewall.PortAny
-		}
-
-	} else {
-		rPort, err := strconv.Atoi(s)
-		if err != nil {
-			return 0, 0, fmt.Errorf("was not a number; `%s`", s)
-		}
-		startPort = int32(rPort)
-		endPort = startPort
 	}
 
-	return
+	groupsHasAny := slices.Contains(r.Groups, "any")
+	if groupsHasAny && len(r.Groups) > 1 {
+		return fmt.Errorf("groups spec [%s] contains the group '\"any\". This rule will ignore the other groups specified", r.Groups)
+	}
+
+	if r.Host == "any" {
+		if !groupsEmpty {
+			return fmt.Errorf("groups specified as %s, but host=any will match any host, regardless of groups", r.Groups)
+		}
+
+		if !cidrEmpty {
+			return fmt.Errorf("cidr specified as %s, but host=any will match any host, regardless of cidr", r.Cidr)
+		}
+	}
+
+	if groupsHasAny {
+		if !hostEmpty && r.Host != "any" {
+			return fmt.Errorf("groups spec [%s] contains the group '\"any\". This rule will ignore the specified host %s", r.Groups, r.Host)
+		}
+		if !cidrEmpty {
+			return fmt.Errorf("groups spec [%s] contains the group '\"any\". This rule will ignore the specified cidr %s", r.Groups, r.Cidr)
+		}
+	}
+
+	if r.Code != "" {
+		return fmt.Errorf("code specified as [%s]. Support for 'code' will be dropped in a future release, as it has never been functional", r.Code)
+	}
+
+	//todo alert on cidr-any
+
+	return nil
+}
+
+func parsePort(s string) (int32, int32, error) {
+	var err error
+	const notAPort int32 = -2
+	if s == "any" {
+		return firewall.PortAny, firewall.PortAny, nil
+	}
+	if s == "fragment" {
+		return firewall.PortFragment, firewall.PortFragment, nil
+	}
+	if !strings.Contains(s, `-`) {
+		rPort, err := strconv.Atoi(s)
+		if err != nil {
+			return notAPort, notAPort, fmt.Errorf("was not a number; `%s`", s)
+		}
+		return int32(rPort), int32(rPort), nil
+	}
+
+	sPorts := strings.SplitN(s, `-`, 2)
+	for i := range sPorts {
+		sPorts[i] = strings.Trim(sPorts[i], " ")
+	}
+	if len(sPorts) != 2 || sPorts[0] == "" || sPorts[1] == "" {
+		return notAPort, notAPort, fmt.Errorf("appears to be a range but could not be parsed; `%s`", s)
+	}
+
+	rStartPort, err := strconv.Atoi(sPorts[0])
+	if err != nil {
+		return notAPort, notAPort, fmt.Errorf("beginning range was not a number; `%s`", sPorts[0])
+	}
+
+	rEndPort, err := strconv.Atoi(sPorts[1])
+	if err != nil {
+		return notAPort, notAPort, fmt.Errorf("ending range was not a number; `%s`", sPorts[1])
+	}
+
+	startPort := int32(rStartPort)
+	endPort := int32(rEndPort)
+
+	if startPort == firewall.PortAny {
+		endPort = firewall.PortAny
+	}
+
+	return startPort, endPort, nil
 }

firewall/packet.go

@@ -22,12 +22,19 @@ const (
 type Packet struct {
 	LocalAddr  netip.Addr
 	RemoteAddr netip.Addr
-	LocalPort  uint16
+	// LocalPort is the destination port for incoming traffic, or the source port for outgoing. Zero for ICMP.
+	LocalPort uint16
+	// RemotePort is the source port for incoming traffic, or the destination port for outgoing.
+	// For ICMP, it's the "identifier". This is only used for connection tracking, actual firewall rules will not filter on ICMP identifier
 	RemotePort uint16
 	Protocol   uint8
 	Fragment   bool
 }
 
+func (fp *Packet) IsIPv4() bool {
+	return fp.LocalAddr.Is4() && fp.RemoteAddr.Is4()
+}
+
 func (fp *Packet) Copy() *Packet {
 	return &Packet{
 		LocalAddr:  fp.LocalAddr,
@@ -46,6 +53,8 @@ func (fp Packet) MarshalJSON() ([]byte, error) {
 		proto = "tcp"
 	case ProtoICMP:
 		proto = "icmp"
+	case ProtoICMPv6:
+		proto = "icmpv6"
 	case ProtoUDP:
 		proto = "udp"
 	default:

go.mod

@@ -1,39 +1,39 @@
 module github.com/slackhq/nebula
 
-go 1.23.0
+go 1.25
-
-toolchain go1.24.1
 
 require (
-	dario.cat/mergo v1.0.1
+	dario.cat/mergo v1.0.2
+	filippo.io/bigmod v0.1.0
 	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be
 	github.com/armon/go-radix v1.0.0
 	github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432
 	github.com/flynn/noise v1.1.0
-	github.com/gaissmai/bart v0.20.4
+	github.com/gaissmai/bart v0.26.0
 	github.com/gogo/protobuf v1.3.2
 	github.com/google/gopacket v1.1.19
-	github.com/kardianos/service v1.2.2
+	github.com/kardianos/service v1.2.4
-	github.com/miekg/dns v1.1.65
+	github.com/miekg/dns v1.1.70
 	github.com/miekg/pkcs11 v1.1.2-0.20231115102856-9078ad6b9d4b
 	github.com/nbrownus/go-metrics-prometheus v0.0.0-20210712211119-974a6260965f
-	github.com/prometheus/client_golang v1.22.0
+	github.com/prometheus/client_golang v1.23.2
 	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475
-	github.com/sirupsen/logrus v1.9.3
+	github.com/sirupsen/logrus v1.9.4
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/stefanberger/go-pkcs11uri v0.0.0-20230803200340-78284954bff6
-	github.com/stretchr/testify v1.10.0
+	github.com/stretchr/testify v1.11.1
-	github.com/vishvananda/netlink v1.3.0
+	github.com/vishvananda/netlink v1.3.1
-	golang.org/x/crypto v0.37.0
+	go.yaml.in/yaml/v3 v3.0.4
+	golang.org/x/crypto v0.47.0
 	golang.org/x/exp v0.0.0-20230725093048-515e97ebf090
-	golang.org/x/net v0.39.0
+	golang.org/x/net v0.49.0
-	golang.org/x/sync v0.13.0
+	golang.org/x/sync v0.19.0
-	golang.org/x/sys v0.32.0
+	golang.org/x/sys v0.40.0
-	golang.org/x/term v0.31.0
+	golang.org/x/term v0.39.0
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard v0.0.0-20230325221338-052af4a8072b
 	golang.zx2c4.com/wireguard/windows v0.5.3
-	google.golang.org/protobuf v1.36.6
+	google.golang.org/protobuf v1.36.11
 	gopkg.in/yaml.v3 v3.0.1
 	gvisor.dev/gvisor v0.0.0-20240423190808-9d7a357edefe
 )
@@ -45,11 +45,12 @@ require (
 	github.com/google/btree v1.1.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/prometheus/client_model v0.6.1 // indirect
+	github.com/prometheus/client_model v0.6.2 // indirect
-	github.com/prometheus/common v0.62.0 // indirect
+	github.com/prometheus/common v0.66.1 // indirect
-	github.com/prometheus/procfs v0.15.1 // indirect
+	github.com/prometheus/procfs v0.16.1 // indirect
-	github.com/vishvananda/netns v0.0.4 // indirect
+	github.com/vishvananda/netns v0.0.5 // indirect
-	golang.org/x/mod v0.23.0 // indirect
+	go.yaml.in/yaml/v2 v2.4.2 // indirect
+	golang.org/x/mod v0.31.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
-	golang.org/x/tools v0.30.0 // indirect
+	golang.org/x/tools v0.40.0 // indirect
 )

go.sum

@@ -1,6 +1,8 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-dario.cat/mergo v1.0.1 h1:Ra4+bf83h2ztPIQYNP99R6m+Y7KfnARDfID+a+vLl4s=
+dario.cat/mergo v1.0.2 h1:85+piFYR1tMbRrLcDwR18y4UKJ3aH1Tbzi24VRW1TK8=
-dario.cat/mergo v1.0.1/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
+dario.cat/mergo v1.0.2/go.mod h1:E/hbnu0NxMFBjpMIE34DRGLWqDy0g5FuKDhCb31ngxA=
+filippo.io/bigmod v0.1.0 h1:UNzDk7y9ADKST+axd9skUpBQeW7fG2KrTZyOE4uGQy8=
+filippo.io/bigmod v0.1.0/go.mod h1:OjOXDNlClLblvXdwgFFOQFJEocLhhtai8vGLy0JCZlI=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
@@ -24,8 +26,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/flynn/noise v1.1.0 h1:KjPQoQCEFdZDiP03phOvGi11+SVVhBG2wOWAorLsstg=
 github.com/flynn/noise v1.1.0/go.mod h1:xbMo+0i6+IGbYdJhF31t2eR1BIU0CYc12+BNAKwUTag=
-github.com/gaissmai/bart v0.20.4 h1:Ik47r1fy3jRVU+1eYzKSW3ho2UgBVTVnUS8O993584U=
+github.com/gaissmai/bart v0.26.0 h1:xOZ57E9hJLBiQaSyeZa9wgWhGuzfGACgqp4BE77OkO0=
-github.com/gaissmai/bart v0.20.4/go.mod h1:cEed+ge8dalcbpi8wtS9x9m2hn/fNJH5suhdGQOHnYk=
+github.com/gaissmai/bart v0.26.0/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
@@ -64,8 +66,8 @@ github.com/json-iterator/go v1.1.10/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/
 github.com/json-iterator/go v1.1.11/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
 github.com/julienschmidt/httprouter v1.2.0/go.mod h1:SYymIcj16QtmaHHD7aYtjjsJG7VTCxuUUipMqKk8s4w=
 github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=
-github.com/kardianos/service v1.2.2 h1:ZvePhAHfvo0A7Mftk/tEzqEZ7Q4lgnR8sGz4xu1YX60=
+github.com/kardianos/service v1.2.4 h1:XNlGtZOYNx2u91urOdg/Kfmc+gfmuIo1Dd3rEi2OgBk=
-github.com/kardianos/service v1.2.2/go.mod h1:CIMRFEJVL+0DS1a3Nx06NaMn4Dz63Ng6O7dl0qH0zVM=
+github.com/kardianos/service v1.2.4/go.mod h1:E4V9ufUuY82F7Ztlu1eN9VXWIQxg8NoLQlmFe0MtrXc=
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
@@ -83,8 +85,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
-github.com/miekg/dns v1.1.65 h1:0+tIPHzUW0GCge7IiK3guGP57VAw7hoPDfApjkMD1Fc=
+github.com/miekg/dns v1.1.70 h1:DZ4u2AV35VJxdD9Fo9fIWm119BsQL5cZU1cQ9s0LkqA=
-github.com/miekg/dns v1.1.65/go.mod h1:Dzw9769uoKVaLuODMDZz9M6ynFU6Em65csPuoi8G0ck=
+github.com/miekg/dns v1.1.70/go.mod h1:+EuEPhdHOsfk6Wk5TT2CzssZdqkmFhf8r+aVyDEToIs=
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@@ -106,24 +108,24 @@ github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXP
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@@ -131,8 +133,8 @@ github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncj
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@@ -143,29 +145,35 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
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@@ -176,8 +184,8 @@ golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLL
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@@ -185,8 +193,8 @@ golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJ
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@@ -197,18 +205,16 @@ golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7w
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+golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.31.0 h1:erwDkOK1Msy6offm1mOgvspSkslFnIGsFnxOKoufg3o=
+golang.org/x/term v0.39.0 h1:RclSuaJf32jOqZz74CkPA9qFuVTX7vhLlpfj/IGWlqY=
-golang.org/x/term v0.31.0/go.mod h1:R4BeIy7D95HzImkxGkTW1UQTtP54tio2RyHz7PwK0aw=
+golang.org/x/term v0.39.0/go.mod h1:yxzUCTP/U+FzoxfdKmLaA0RV1WgE0VY7hXBwKtY/4ww=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
@@ -219,8 +225,8 @@ golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtn
 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
-golang.org/x/tools v0.30.0 h1:BgcpHewrV5AUp2G9MebG4XPFI1E2W41zU1SaqVA9vJY=
+golang.org/x/tools v0.40.0 h1:yLkxfA+Qnul4cs9QA3KnlFu0lVmd8JJfoq+E41uSutA=
-golang.org/x/tools v0.30.0/go.mod h1:c347cR/OJfw5TI+GfX7RUPNMdDRRbjvYTS0jPyvsVtY=
+golang.org/x/tools v0.40.0/go.mod h1:Ik/tzLRlbscWpqqMRjyWYDisX8bG13FrdXp3o4Sr9lc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
@@ -239,8 +245,8 @@ google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miE
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
-google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
+google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
-google.golang.org/protobuf v1.36.6/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
+google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

handshake_ix.go

@@ -1,8 +1,8 @@
 package nebula
 
 import (
+	"bytes"
 	"net/netip"
-	"slices"
 	"time"
 
 	"github.com/flynn/noise"
@@ -23,13 +23,17 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 		return false
 	}
 
-	// If we're connecting to a v6 address we must use a v2 cert
 	cs := f.pki.getCertState()
 	v := cs.initiatingVersion
-	for _, a := range hh.hostinfo.vpnAddrs {
+	if hh.initiatingVersionOverride != cert.VersionPre1 {
-		if a.Is6() {
+		v = hh.initiatingVersionOverride
-			v = cert.Version2
+	} else if v < cert.Version2 {
-			break
+		// If we're connecting to a v6 address we should encourage use of a V2 cert
+		for _, a := range hh.hostinfo.vpnAddrs {
+			if a.Is6() {
+				v = cert.Version2
+				break
+			}
 		}
 	}
 
@@ -48,6 +52,7 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 			WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).
 			WithField("certVersion", v).
 			Error("Unable to handshake with host because no certificate handshake bytes is available")
+		return false
 	}
 
 	ci, err := NewConnectionState(f.l, cs, crt, true, noise.HandshakeIX)
@@ -95,19 +100,20 @@ func ixHandshakeStage0(f *Interface, hh *HandshakeHostInfo) bool {
 	return true
 }
 
-func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet []byte, h *header.H) {
+func ixHandshakeStage1(f *Interface, via ViaSender, packet []byte, h *header.H) {
 	cs := f.pki.getCertState()
 	crt := cs.GetDefaultCertificate()
 	if crt == nil {
-		f.l.WithField("udpAddr", addr).
+		f.l.WithField("from", via).
 			WithField("handshake", m{"stage": 0, "style": "ix_psk0"}).
 			WithField("certVersion", cs.initiatingVersion).
 			Error("Unable to handshake with host because no certificate is available")
+		return
 	}
 
 	ci, err := NewConnectionState(f.l, cs, crt, false, noise.HandshakeIX)
 	if err != nil {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			Error("Failed to create connection state")
 		return
@@ -118,7 +124,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	msg, _, _, err := ci.H.ReadMessage(nil, packet[header.Len:])
 	if err != nil {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			Error("Failed to call noise.ReadMessage")
 		return
@@ -127,7 +133,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 	hs := &NebulaHandshake{}
 	err = hs.Unmarshal(msg)
 	if err != nil || hs.Details == nil {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			Error("Failed unmarshal handshake message")
 		return
@@ -135,7 +141,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	rc, err := cert.Recombine(cert.Version(hs.Details.CertVersion), hs.Details.Cert, ci.H.PeerStatic(), ci.Curve())
 	if err != nil {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			Info("Handshake did not contain a certificate")
 		return
@@ -143,12 +149,12 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	remoteCert, err := f.pki.GetCAPool().VerifyCertificate(time.Now(), rc)
 	if err != nil {
-		fp, err := rc.Fingerprint()
+		fp, fperr := rc.Fingerprint()
-		if err != nil {
+		if fperr != nil {
 			fp = "<error generating certificate fingerprint>"
 		}
 
-		e := f.l.WithError(err).WithField("udpAddr", addr).
+		e := f.l.WithError(err).WithField("from", via).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			WithField("certVpnNetworks", rc.Networks()).
 			WithField("certFingerprint", fp)
@@ -161,39 +167,49 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 		return
 	}
 
+	if !bytes.Equal(remoteCert.Certificate.PublicKey(), ci.H.PeerStatic()) {
+		f.l.WithField("from", via).
+			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
+			WithField("cert", remoteCert).Info("public key mismatch between certificate and handshake")
+		return
+	}
+
 	if remoteCert.Certificate.Version() != ci.myCert.Version() {
 		// We started off using the wrong certificate version, lets see if we can match the version that was sent to us
-		rc := cs.getCertificate(remoteCert.Certificate.Version())
+		myCertOtherVersion := cs.getCertificate(remoteCert.Certificate.Version())
-		if rc == nil {
+		if myCertOtherVersion == nil {
-			f.l.WithError(err).WithField("udpAddr", addr).
+			if f.l.Level >= logrus.DebugLevel {
-				WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).WithField("cert", remoteCert).
+				f.l.WithError(err).WithFields(m{
-				Info("Unable to handshake with host due to missing certificate version")
+					"from":      via,
-			return
+					"handshake": m{"stage": 1, "style": "ix_psk0"},
+					"cert":      remoteCert,
+				}).Debug("Might be unable to handshake with host due to missing certificate version")
+			}
+		} else {
+			// Record the certificate we are actually using
+			ci.myCert = myCertOtherVersion
 		}
-
-		// Record the certificate we are actually using
-		ci.myCert = rc
 	}
 
 	if len(remoteCert.Certificate.Networks()) == 0 {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("cert", remoteCert).
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
 			Info("No networks in certificate")
 		return
 	}
 
-	var vpnAddrs []netip.Addr
-	var filteredNetworks []netip.Prefix
 	certName := remoteCert.Certificate.Name()
 	certVersion := remoteCert.Certificate.Version()
 	fingerprint := remoteCert.Fingerprint
 	issuer := remoteCert.Certificate.Issuer()
+	vpnNetworks := remoteCert.Certificate.Networks()
 
-	for _, network := range remoteCert.Certificate.Networks() {
+	anyVpnAddrsInCommon := false
-		vpnAddr := network.Addr()
+	vpnAddrs := make([]netip.Addr, len(vpnNetworks))
-		if f.myVpnAddrsTable.Contains(vpnAddr) {
+	for i, network := range vpnNetworks {
-			f.l.WithField("vpnAddr", vpnAddr).WithField("udpAddr", addr).
+		if f.myVpnAddrsTable.Contains(network.Addr()) {
+			f.l.WithField("vpnNetworks", vpnNetworks).WithField("from", via).
 				WithField("certName", certName).
 				WithField("certVersion", certVersion).
 				WithField("fingerprint", fingerprint).
@@ -201,38 +217,24 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 				WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Refusing to handshake with myself")
 			return
 		}
-
+		vpnAddrs[i] = network.Addr()
-		// vpnAddrs outside our vpn networks are of no use to us, filter them out
+		if f.myVpnNetworksTable.Contains(network.Addr()) {
-		if !f.myVpnNetworksTable.Contains(vpnAddr) {
+			anyVpnAddrsInCommon = true
-			continue
 		}
-
-		filteredNetworks = append(filteredNetworks, network)
-		vpnAddrs = append(vpnAddrs, vpnAddr)
 	}
 
-	if len(vpnAddrs) == 0 {
+	if !via.IsRelayed {
-		f.l.WithError(err).WithField("udpAddr", addr).
-			WithField("certName", certName).
-			WithField("certVersion", certVersion).
-			WithField("fingerprint", fingerprint).
-			WithField("issuer", issuer).
-			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("No usable vpn addresses from host, refusing handshake")
-		return
-	}
-
-	if addr.IsValid() {
-		// addr can be invalid when the tunnel is being relayed.
 		// We only want to apply the remote allow list for direct tunnels here
-		if !f.lightHouse.GetRemoteAllowList().AllowAll(vpnAddrs, addr.Addr()) {
+		if !f.lightHouse.GetRemoteAllowList().AllowAll(vpnAddrs, via.UdpAddr.Addr()) {
-			f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).Debug("lighthouse.remote_allow_list denied incoming handshake")
+			f.l.WithField("vpnAddrs", vpnAddrs).WithField("from", via).
+				Debug("lighthouse.remote_allow_list denied incoming handshake")
 			return
 		}
 	}
 
 	myIndex, err := generateIndex(f.l)
 	if err != nil {
-		f.l.WithError(err).WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("vpnAddrs", vpnAddrs).WithField("from", via).
 			WithField("certName", certName).
 			WithField("certVersion", certVersion).
 			WithField("fingerprint", fingerprint).
@@ -249,32 +251,36 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 		HandshakePacket:   make(map[uint8][]byte, 0),
 		lastHandshakeTime: hs.Details.Time,
 		relayState: RelayState{
-			relays:         map[netip.Addr]struct{}{},
+			relays:         nil,
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},
 		},
 	}
 
-	f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+	msgRxL := f.l.WithFields(m{
-		WithField("certName", certName).
+		"vpnAddrs":       vpnAddrs,
-		WithField("certVersion", certVersion).
+		"from":           via,
-		WithField("fingerprint", fingerprint).
+		"certName":       certName,
-		WithField("issuer", issuer).
+		"certVersion":    certVersion,
-		WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
+		"fingerprint":    fingerprint,
-		WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
+		"issuer":         issuer,
-		Info("Handshake message received")
+		"initiatorIndex": hs.Details.InitiatorIndex,
+		"responderIndex": hs.Details.ResponderIndex,
+		"remoteIndex":    h.RemoteIndex,
+		"handshake":      m{"stage": 1, "style": "ix_psk0"},
+	})
+
+	if anyVpnAddrsInCommon {
+		msgRxL.Info("Handshake message received")
+	} else {
+		//todo warn if not lighthouse or relay?
+		msgRxL.Info("Handshake message received, but no vpnNetworks in common.")
+	}
 
 	hs.Details.ResponderIndex = myIndex
 	hs.Details.Cert = cs.getHandshakeBytes(ci.myCert.Version())
 	if hs.Details.Cert == nil {
-		f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+		msgRxL.WithField("myCertVersion", ci.myCert.Version()).
-			WithField("certName", certName).
-			WithField("certVersion", certVersion).
-			WithField("fingerprint", fingerprint).
-			WithField("issuer", issuer).
-			WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
-			WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).
-			WithField("certVersion", ci.myCert.Version()).
 			Error("Unable to handshake with host because no certificate handshake bytes is available")
 		return
 	}
@@ -285,7 +291,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	hsBytes, err := hs.Marshal()
 	if err != nil {
-		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("certName", certName).
 			WithField("certVersion", certVersion).
 			WithField("fingerprint", fingerprint).
@@ -297,7 +303,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 	nh := header.Encode(make([]byte, header.Len), header.Version, header.Handshake, header.HandshakeIXPSK0, hs.Details.InitiatorIndex, 2)
 	msg, dKey, eKey, err := ci.H.WriteMessage(nh, hsBytes)
 	if err != nil {
-		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("certName", certName).
 			WithField("certVersion", certVersion).
 			WithField("fingerprint", fingerprint).
@@ -305,7 +311,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 			WithField("handshake", m{"stage": 1, "style": "ix_psk0"}).Error("Failed to call noise.WriteMessage")
 		return
 	} else if dKey == nil || eKey == nil {
-		f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("certName", certName).
 			WithField("certVersion", certVersion).
 			WithField("fingerprint", fingerprint).
@@ -331,15 +337,17 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 	ci.eKey = NewNebulaCipherState(eKey)
 
 	hostinfo.remotes = f.lightHouse.QueryCache(vpnAddrs)
-	hostinfo.SetRemote(addr)
+	if !via.IsRelayed {
-	hostinfo.buildNetworks(filteredNetworks, remoteCert.Certificate.UnsafeNetworks())
+		hostinfo.SetRemote(via.UdpAddr)
+	}
+	hostinfo.buildNetworks(f.myVpnNetworksTable, remoteCert.Certificate)
 
 	existing, err := f.handshakeManager.CheckAndComplete(hostinfo, 0, f)
 	if err != nil {
 		switch err {
 		case ErrAlreadySeen:
 			// Update remote if preferred
-			if existing.SetRemoteIfPreferred(f.hostMap, addr) {
+			if existing.SetRemoteIfPreferred(f.hostMap, via) {
 				// Send a test packet to ensure the other side has also switched to
 				// the preferred remote
 				f.SendMessageToVpnAddr(header.Test, header.TestRequest, vpnAddrs[0], []byte(""), make([]byte, 12, 12), make([]byte, mtu))
@@ -347,21 +355,21 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 			msg = existing.HandshakePacket[2]
 			f.messageMetrics.Tx(header.Handshake, header.MessageSubType(msg[1]), 1)
-			if addr.IsValid() {
+			if !via.IsRelayed {
-				err := f.outside.WriteTo(msg, addr)
+				err := f.outside.WriteTo(msg, via.UdpAddr)
 				if err != nil {
-					f.l.WithField("vpnAddrs", existing.vpnAddrs).WithField("udpAddr", addr).
+					f.l.WithField("vpnAddrs", existing.vpnAddrs).WithField("from", via).
 						WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("cached", true).
 						WithError(err).Error("Failed to send handshake message")
 				} else {
-					f.l.WithField("vpnAddrs", existing.vpnAddrs).WithField("udpAddr", addr).
+					f.l.WithField("vpnAddrs", existing.vpnAddrs).WithField("from", via).
 						WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("cached", true).
 						Info("Handshake message sent")
 				}
 				return
 			} else {
-				if via == nil {
+				if via.relay == nil {
-					f.l.Error("Handshake send failed: both addr and via are nil.")
+					f.l.Error("Handshake send failed: both addr and via.relay are nil.")
 					return
 				}
 				hostinfo.relayState.InsertRelayTo(via.relayHI.vpnAddrs[0])
@@ -373,7 +381,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 			}
 		case ErrExistingHostInfo:
 			// This means there was an existing tunnel and this handshake was older than the one we are currently based on
-			f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+			f.l.WithField("vpnAddrs", vpnAddrs).WithField("from", via).
 				WithField("certName", certName).
 				WithField("certVersion", certVersion).
 				WithField("oldHandshakeTime", existing.lastHandshakeTime).
@@ -389,7 +397,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 			return
 		case ErrLocalIndexCollision:
 			// This means we failed to insert because of collision on localIndexId. Just let the next handshake packet retry
-			f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+			f.l.WithField("vpnAddrs", vpnAddrs).WithField("from", via).
 				WithField("certName", certName).
 				WithField("certVersion", certVersion).
 				WithField("fingerprint", fingerprint).
@@ -402,7 +410,7 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 		default:
 			// Shouldn't happen, but just in case someone adds a new error type to CheckAndComplete
 			// And we forget to update it here
-			f.l.WithError(err).WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+			f.l.WithError(err).WithField("vpnAddrs", vpnAddrs).WithField("from", via).
 				WithField("certName", certName).
 				WithField("certVersion", certVersion).
 				WithField("fingerprint", fingerprint).
@@ -416,30 +424,23 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 
 	// Do the send
 	f.messageMetrics.Tx(header.Handshake, header.MessageSubType(msg[1]), 1)
-	if addr.IsValid() {
+	if !via.IsRelayed {
-		err = f.outside.WriteTo(msg, addr)
+		err = f.outside.WriteTo(msg, via.UdpAddr)
+		log := f.l.WithField("vpnAddrs", vpnAddrs).WithField("from", via).
+			WithField("certName", certName).
+			WithField("certVersion", certVersion).
+			WithField("fingerprint", fingerprint).
+			WithField("issuer", issuer).
+			WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
+			WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"})
 		if err != nil {
-			f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+			log.WithError(err).Error("Failed to send handshake")
-				WithField("certName", certName).
-				WithField("certVersion", certVersion).
-				WithField("fingerprint", fingerprint).
-				WithField("issuer", issuer).
-				WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
-				WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
-				WithError(err).Error("Failed to send handshake")
 		} else {
-			f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+			log.Info("Handshake message sent")
-				WithField("certName", certName).
-				WithField("certVersion", certVersion).
-				WithField("fingerprint", fingerprint).
-				WithField("issuer", issuer).
-				WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
-				WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
-				Info("Handshake message sent")
 		}
 	} else {
-		if via == nil {
+		if via.relay == nil {
-			f.l.Error("Handshake send failed: both addr and via are nil.")
+			f.l.Error("Handshake send failed: both addr and via.relay are nil.")
 			return
 		}
 		hostinfo.relayState.InsertRelayTo(via.relayHI.vpnAddrs[0])
@@ -457,14 +458,14 @@ func ixHandshakeStage1(f *Interface, addr netip.AddrPort, via *ViaSender, packet
 			Info("Handshake message sent")
 	}
 
-	f.connectionManager.AddTrafficWatch(hostinfo.localIndexId)
+	f.connectionManager.AddTrafficWatch(hostinfo)
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 
 	return
 }
 
-func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *HandshakeHostInfo, packet []byte, h *header.H) bool {
+func ixHandshakeStage2(f *Interface, via ViaSender, hh *HandshakeHostInfo, packet []byte, h *header.H) bool {
 	if hh == nil {
 		// Nothing here to tear down, got a bogus stage 2 packet
 		return true
@@ -474,10 +475,10 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 	defer hh.Unlock()
 
 	hostinfo := hh.hostinfo
-	if addr.IsValid() {
+	if !via.IsRelayed {
 		// The vpnAddr we know about is the one we tried to handshake with, use it to apply the remote allow list.
-		if !f.lightHouse.GetRemoteAllowList().AllowAll(hostinfo.vpnAddrs, addr.Addr()) {
+		if !f.lightHouse.GetRemoteAllowList().AllowAll(hostinfo.vpnAddrs, via.UdpAddr.Addr()) {
-			f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).Debug("lighthouse.remote_allow_list denied incoming handshake")
+			f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).Debug("lighthouse.remote_allow_list denied incoming handshake")
 			return false
 		}
 	}
@@ -485,7 +486,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 	ci := hostinfo.ConnectionState
 	msg, eKey, dKey, err := ci.H.ReadMessage(nil, packet[header.Len:])
 	if err != nil {
-		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).WithField("header", h).
 			Error("Failed to call noise.ReadMessage")
 
@@ -494,7 +495,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		// near future
 		return false
 	} else if dKey == nil || eKey == nil {
-		f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
 			Error("Noise did not arrive at a key")
 
@@ -506,7 +507,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 	hs := &NebulaHandshake{}
 	err = hs.Unmarshal(msg)
 	if err != nil || hs.Details == nil {
-		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("vpnAddrs", hostinfo.vpnAddrs).WithField("from", via).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).Error("Failed unmarshal handshake message")
 
 		// The handshake state machine is complete, if things break now there is no chance to recover. Tear down and start again
@@ -515,7 +516,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 
 	rc, err := cert.Recombine(cert.Version(hs.Details.CertVersion), hs.Details.Cert, ci.H.PeerStatic(), ci.Curve())
 	if err != nil {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("vpnAddrs", hostinfo.vpnAddrs).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
 			Info("Handshake did not contain a certificate")
@@ -529,7 +530,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 			fp = "<error generating certificate fingerprint>"
 		}
 
-		e := f.l.WithError(err).WithField("udpAddr", addr).
+		e := f.l.WithError(err).WithField("from", via).
 			WithField("vpnAddrs", hostinfo.vpnAddrs).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
 			WithField("certFingerprint", fp).
@@ -542,9 +543,15 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		e.Info("Invalid certificate from host")
 		return true
 	}
+	if !bytes.Equal(remoteCert.Certificate.PublicKey(), ci.H.PeerStatic()) {
+		f.l.WithField("from", via).
+			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
+			WithField("cert", remoteCert).Info("public key mismatch between certificate and handshake")
+		return true
+	}
 
 	if len(remoteCert.Certificate.Networks()) == 0 {
-		f.l.WithError(err).WithField("udpAddr", addr).
+		f.l.WithError(err).WithField("from", via).
 			WithField("vpnAddrs", hostinfo.vpnAddrs).
 			WithField("cert", remoteCert).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
@@ -567,39 +574,30 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 	ci.eKey = NewNebulaCipherState(eKey)
 
 	// Make sure the current udpAddr being used is set for responding
-	if addr.IsValid() {
+	if !via.IsRelayed {
-		hostinfo.SetRemote(addr)
+		hostinfo.SetRemote(via.UdpAddr)
 	} else {
 		hostinfo.relayState.InsertRelayTo(via.relayHI.vpnAddrs[0])
 	}
 
-	var vpnAddrs []netip.Addr
+	correctHostResponded := false
-	var filteredNetworks []netip.Prefix
+	anyVpnAddrsInCommon := false
-	for _, network := range vpnNetworks {
+	vpnAddrs := make([]netip.Addr, len(vpnNetworks))
-		// vpnAddrs outside our vpn networks are of no use to us, filter them out
+	for i, network := range vpnNetworks {
-		vpnAddr := network.Addr()
+		vpnAddrs[i] = network.Addr()
-		if !f.myVpnNetworksTable.Contains(vpnAddr) {
+		if f.myVpnNetworksTable.Contains(network.Addr()) {
-			continue
+			anyVpnAddrsInCommon = true
+		}
+		if hostinfo.vpnAddrs[0] == network.Addr() {
+			// todo is it more correct to see if any of hostinfo.vpnAddrs are in the cert? it should have len==1, but one day it might not?
+			correctHostResponded = true
 		}
-
-		filteredNetworks = append(filteredNetworks, network)
-		vpnAddrs = append(vpnAddrs, vpnAddr)
-	}
-
-	if len(vpnAddrs) == 0 {
-		f.l.WithError(err).WithField("udpAddr", addr).
-			WithField("certName", certName).
-			WithField("certVersion", certVersion).
-			WithField("fingerprint", fingerprint).
-			WithField("issuer", issuer).
-			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).Error("No usable vpn addresses from host, refusing handshake")
-		return true
 	}
 
 	// Ensure the right host responded
-	if !slices.Contains(vpnAddrs, hostinfo.vpnAddrs[0]) {
+	if !correctHostResponded {
 		f.l.WithField("intendedVpnAddrs", hostinfo.vpnAddrs).WithField("haveVpnNetworks", vpnNetworks).
-			WithField("udpAddr", addr).
+			WithField("from", via).
 			WithField("certName", certName).
 			WithField("certVersion", certVersion).
 			WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
@@ -609,10 +607,11 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		f.handshakeManager.DeleteHostInfo(hostinfo)
 
 		// Create a new hostinfo/handshake for the intended vpn ip
+		//TODO is hostinfo.vpnAddrs[0] always the address to use?
 		f.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], func(newHH *HandshakeHostInfo) {
 			// Block the current used address
 			newHH.hostinfo.remotes = hostinfo.remotes
-			newHH.hostinfo.remotes.BlockRemote(addr)
+			newHH.hostinfo.remotes.BlockRemote(via)
 
 			f.l.WithField("blockedUdpAddrs", newHH.hostinfo.remotes.CopyBlockedRemotes()).
 				WithField("vpnNetworks", vpnNetworks).
@@ -635,7 +634,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 	ci.window.Update(f.l, 2)
 
 	duration := time.Since(hh.startTime).Nanoseconds()
-	f.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", addr).
+	msgRxL := f.l.WithField("vpnAddrs", vpnAddrs).WithField("from", via).
 		WithField("certName", certName).
 		WithField("certVersion", certVersion).
 		WithField("fingerprint", fingerprint).
@@ -643,16 +642,21 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		WithField("initiatorIndex", hs.Details.InitiatorIndex).WithField("responderIndex", hs.Details.ResponderIndex).
 		WithField("remoteIndex", h.RemoteIndex).WithField("handshake", m{"stage": 2, "style": "ix_psk0"}).
 		WithField("durationNs", duration).
-		WithField("sentCachedPackets", len(hh.packetStore)).
+		WithField("sentCachedPackets", len(hh.packetStore))
-		Info("Handshake message received")
+	if anyVpnAddrsInCommon {
+		msgRxL.Info("Handshake message received")
+	} else {
+		//todo warn if not lighthouse or relay?
+		msgRxL.Info("Handshake message received, but no vpnNetworks in common.")
+	}
 
 	// Build up the radix for the firewall if we have subnets in the cert
 	hostinfo.vpnAddrs = vpnAddrs
-	hostinfo.buildNetworks(filteredNetworks, remoteCert.Certificate.UnsafeNetworks())
+	hostinfo.buildNetworks(f.myVpnNetworksTable, remoteCert.Certificate)
 
 	// Complete our handshake and update metrics, this will replace any existing tunnels for the vpnAddrs here
 	f.handshakeManager.Complete(hostinfo, f)
-	f.connectionManager.AddTrafficWatch(hostinfo.localIndexId)
+	f.connectionManager.AddTrafficWatch(hostinfo)
 
 	if f.l.Level >= logrus.DebugLevel {
 		hostinfo.logger(f.l).Debugf("Sending %d stored packets", len(hh.packetStore))
@@ -667,7 +671,7 @@ func ixHandshakeStage2(f *Interface, addr netip.AddrPort, via *ViaSender, hh *Ha
 		f.cachedPacketMetrics.sent.Inc(int64(len(hh.packetStore)))
 	}
 
-	hostinfo.remotes.ResetBlockedRemotes()
+	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 	f.metricHandshakes.Update(duration)
 
 	return false

handshake_manager.go

@@ -68,11 +68,12 @@ type HandshakeManager struct {
 type HandshakeHostInfo struct {
 	sync.Mutex
 
-	startTime   time.Time        // Time that we first started trying with this handshake
+	startTime                 time.Time        // Time that we first started trying with this handshake
-	ready       bool             // Is the handshake ready
+	ready                     bool             // Is the handshake ready
-	counter     int64            // How many attempts have we made so far
+	initiatingVersionOverride cert.Version     // Should we use a non-default cert version for this handshake?
-	lastRemotes []netip.AddrPort // Remotes that we sent to during the previous attempt
+	counter                   int64            // How many attempts have we made so far
-	packetStore []*cachedPacket  // A set of packets to be transmitted once the handshake completes
+	lastRemotes               []netip.AddrPort // Remotes that we sent to during the previous attempt
+	packetStore               []*cachedPacket  // A set of packets to be transmitted once the handshake completes
 
 	hostinfo *HostInfo
 }
@@ -135,11 +136,11 @@ func (hm *HandshakeManager) Run(ctx context.Context) {
 	}
 }
 
-func (hm *HandshakeManager) HandleIncoming(addr netip.AddrPort, via *ViaSender, packet []byte, h *header.H) {
+func (hm *HandshakeManager) HandleIncoming(via ViaSender, packet []byte, h *header.H) {
 	// First remote allow list check before we know the vpnIp
-	if addr.IsValid() {
+	if !via.IsRelayed {
-		if !hm.lightHouse.GetRemoteAllowList().AllowUnknownVpnAddr(addr.Addr()) {
+		if !hm.lightHouse.GetRemoteAllowList().AllowUnknownVpnAddr(via.UdpAddr.Addr()) {
-			hm.l.WithField("udpAddr", addr).Debug("lighthouse.remote_allow_list denied incoming handshake")
+			hm.l.WithField("from", via).Debug("lighthouse.remote_allow_list denied incoming handshake")
 			return
 		}
 	}
@@ -148,11 +149,11 @@ func (hm *HandshakeManager) HandleIncoming(addr netip.AddrPort, via *ViaSender,
 	case header.HandshakeIXPSK0:
 		switch h.MessageCounter {
 		case 1:
-			ixHandshakeStage1(hm.f, addr, via, packet, h)
+			ixHandshakeStage1(hm.f, via, packet, h)
 
 		case 2:
 			newHostinfo := hm.queryIndex(h.RemoteIndex)
-			tearDown := ixHandshakeStage2(hm.f, addr, via, newHostinfo, packet, h)
+			tearDown := ixHandshakeStage2(hm.f, via, newHostinfo, packet, h)
 			if tearDown && newHostinfo != nil {
 				hm.DeleteHostInfo(newHostinfo.hostinfo)
 			}
@@ -268,12 +269,12 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 		hostinfo.logger(hm.l).WithField("relays", hostinfo.remotes.relays).Info("Attempt to relay through hosts")
 		// Send a RelayRequest to all known Relay IP's
 		for _, relay := range hostinfo.remotes.relays {
-			// Don't relay to myself
+			// Don't relay through the host I'm trying to connect to
 			if relay == vpnIp {
 				continue
 			}
 
-			// Don't relay through the host I'm trying to connect to
+			// Don't relay to myself
 			if hm.f.myVpnAddrsTable.Contains(relay) {
 				continue
 			}
@@ -450,7 +451,7 @@ func (hm *HandshakeManager) StartHandshake(vpnAddr netip.Addr, cacheCb func(*Han
 		vpnAddrs:        []netip.Addr{vpnAddr},
 		HandshakePacket: make(map[uint8][]byte, 0),
 		relayState: RelayState{
-			relays:         map[netip.Addr]struct{}{},
+			relays:         nil,
 			relayForByAddr: map[netip.Addr]*Relay{},
 			relayForByIdx:  map[uint32]*Relay{},
 		},
@@ -589,7 +590,7 @@ func (hm *HandshakeManager) allocateIndex(hh *HandshakeHostInfo) error {
 	hm.Lock()
 	defer hm.Unlock()
 
-	for i := 0; i < 32; i++ {
+	for range 32 {
 		index, err := generateIndex(hm.l)
 		if err != nil {
 			return err

hostmap.go

@@ -1,9 +1,12 @@
 package nebula
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
 	"net"
 	"net/netip"
+	"slices"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -16,12 +19,10 @@ import (
 	"github.com/slackhq/nebula/header"
 )
 
-// const ProbeLen = 100
 const defaultPromoteEvery = 1000       // Count of packets sent before we try moving a tunnel to a preferred underlay ip address
 const defaultReQueryEvery = 5000       // Count of packets sent before re-querying a hostinfo to the lighthouse
 const defaultReQueryWait = time.Minute // Minimum amount of seconds to wait before re-querying a hostinfo the lighthouse. Evaluated every ReQueryEvery
 const MaxRemotes = 10
-const maxRecvError = 4
 
 // MaxHostInfosPerVpnIp is the max number of hostinfos we will track for a given vpn ip
 // 5 allows for an initial handshake and each host pair re-handshaking twice
@@ -68,7 +69,7 @@ type HostMap struct {
 type RelayState struct {
 	sync.RWMutex
 
-	relays map[netip.Addr]struct{} // Set of vpnAddr's of Hosts to use as relays to access this peer
+	relays []netip.Addr // Ordered set of VpnAddrs of Hosts to use as relays to access this peer
 	// For data race avoidance, the contents of a *Relay are treated immutably. To update a *Relay, copy the existing data,
 	// modify what needs to be updated, and store the new modified copy in the relayForByIp and relayForByIdx maps (with
 	// the RelayState Lock held)
@@ -79,7 +80,12 @@ type RelayState struct {
 func (rs *RelayState) DeleteRelay(ip netip.Addr) {
 	rs.Lock()
 	defer rs.Unlock()
-	delete(rs.relays, ip)
+	for idx, val := range rs.relays {
+		if val == ip {
+			rs.relays = append(rs.relays[:idx], rs.relays[idx+1:]...)
+			return
+		}
+	}
 }
 
 func (rs *RelayState) UpdateRelayForByIpState(vpnIp netip.Addr, state int) {
@@ -124,16 +130,16 @@ func (rs *RelayState) GetRelayForByAddr(addr netip.Addr) (*Relay, bool) {
 func (rs *RelayState) InsertRelayTo(ip netip.Addr) {
 	rs.Lock()
 	defer rs.Unlock()
-	rs.relays[ip] = struct{}{}
+	if !slices.Contains(rs.relays, ip) {
+		rs.relays = append(rs.relays, ip)
+	}
 }
 
 func (rs *RelayState) CopyRelayIps() []netip.Addr {
+	ret := make([]netip.Addr, len(rs.relays))
 	rs.RLock()
 	defer rs.RUnlock()
-	ret := make([]netip.Addr, 0, len(rs.relays))
+	copy(ret, rs.relays)
-	for ip := range rs.relays {
-		ret = append(ret, ip)
-	}
 	return ret
 }
 
@@ -208,6 +214,21 @@ func (rs *RelayState) InsertRelay(ip netip.Addr, idx uint32, r *Relay) {
 	rs.relayForByIdx[idx] = r
 }
 
+type NetworkType uint8
+
+const (
+	NetworkTypeUnknown NetworkType = iota
+	// NetworkTypeVPN is a network that overlaps one or more of the vpnNetworks in our certificate
+	NetworkTypeVPN
+	// NetworkTypeVPNPeer is a network that does not overlap one of our networks
+	NetworkTypeVPNPeer
+	// NetworkTypeUnsafe is a network from Certificate.UnsafeNetworks()
+	NetworkTypeUnsafe
+	// NetworkTypeUnverifiedSNATPeer is used to indicate traffic we're willing to route, but never deliver to a NetworkTypeVPN
+	NetworkTypeUnverifiedSNATPeer
+	NetworkTypeInvalidPeer
+)
+
 type HostInfo struct {
 	remote          netip.AddrPort
 	remotes         *RemoteList
@@ -219,11 +240,10 @@ type HostInfo struct {
 	// vpnAddrs is a list of vpn addresses assigned to this host that are within our own vpn networks
 	// The host may have other vpn addresses that are outside our
 	// vpn networks but were removed because they are not usable
-	vpnAddrs  []netip.Addr
+	vpnAddrs []netip.Addr
-	recvError atomic.Uint32
 
-	// networks are both all vpn and unsafe networks assigned to this host
+	// networks is a combination of specific vpn addresses (not prefixes!) and full unsafe networks assigned to this host.
-	networks   *bart.Lite
+	networks   *bart.Table[NetworkType]
 	relayState RelayState
 
 	// HandshakePacket records the packets used to create this hostinfo
@@ -250,12 +270,45 @@ type HostInfo struct {
 	// Used to track other hostinfos for this vpn ip since only 1 can be primary
 	// Synchronised via hostmap lock and not the hostinfo lock.
 	next, prev *HostInfo
+
+	//TODO: in, out, and others might benefit from being an atomic.Int32. We could collapse connectionManager pendingDeletion, relayUsed, and in/out into this 1 thing
+	in, out, pendingDeletion atomic.Bool
+
+	// lastUsed tracks the last time ConnectionManager checked the tunnel and it was in use.
+	// This value will be behind against actual tunnel utilization in the hot path.
+	// This should only be used by the ConnectionManagers ticker routine.
+	lastUsed time.Time
+}
+
+func (i *HostInfo) HasOnlyV6Addresses() bool {
+	for _, vpnIp := range i.vpnAddrs {
+		if !vpnIp.Is6() {
+			return false
+		}
+	}
+	return true
 }
 
 type ViaSender struct {
+	UdpAddr   netip.AddrPort
 	relayHI   *HostInfo // relayHI is the host info object of the relay
 	remoteIdx uint32    // remoteIdx is the index included in the header of the received packet
 	relay     *Relay    // relay contains the rest of the relay information, including the PeerIP of the host trying to communicate with us.
+	IsRelayed bool      // IsRelayed is true if the packet was sent through a relay
+}
+
+func (v ViaSender) String() string {
+	if v.IsRelayed {
+		return fmt.Sprintf("%s (relayed)", v.UdpAddr)
+	}
+	return v.UdpAddr.String()
+}
+
+func (v ViaSender) MarshalJSON() ([]byte, error) {
+	if v.IsRelayed {
+		return json.Marshal(m{"relay": v.UdpAddr})
+	}
+	return json.Marshal(m{"direct": v.UdpAddr})
 }
 
 type cachedPacket struct {
@@ -671,6 +724,7 @@ func (i *HostInfo) GetCert() *cert.CachedCertificate {
 	return nil
 }
 
+// TODO: Maybe use ViaSender here?
 func (i *HostInfo) SetRemote(remote netip.AddrPort) {
 	// We copy here because we likely got this remote from a source that reuses the object
 	if i.remote != remote {
@@ -681,14 +735,14 @@ func (i *HostInfo) SetRemote(remote netip.AddrPort) {
 
 // SetRemoteIfPreferred returns true if the remote was changed. The lastRoam
 // time on the HostInfo will also be updated.
-func (i *HostInfo) SetRemoteIfPreferred(hm *HostMap, newRemote netip.AddrPort) bool {
+func (i *HostInfo) SetRemoteIfPreferred(hm *HostMap, via ViaSender) bool {
-	if !newRemote.IsValid() {
+	if via.IsRelayed {
-		// relays have nil udp Addrs
 		return false
 	}
+
 	currentRemote := i.remote
 	if !currentRemote.IsValid() {
-		i.SetRemote(newRemote)
+		i.SetRemote(via.UdpAddr)
 		return true
 	}
 
@@ -701,7 +755,7 @@ func (i *HostInfo) SetRemoteIfPreferred(hm *HostMap, newRemote netip.AddrPort) b
 			return false
 		}
 
-		if l.Contains(newRemote.Addr()) {
+		if l.Contains(via.UdpAddr.Addr()) {
 			newIsPreferred = true
 		}
 	}
@@ -711,7 +765,7 @@ func (i *HostInfo) SetRemoteIfPreferred(hm *HostMap, newRemote netip.AddrPort) b
 		i.lastRoam = time.Now()
 		i.lastRoamRemote = currentRemote
 
-		i.SetRemote(newRemote)
+		i.SetRemote(via.UdpAddr)
 
 		return true
 	}
@@ -719,26 +773,26 @@ func (i *HostInfo) SetRemoteIfPreferred(hm *HostMap, newRemote netip.AddrPort) b
 	return false
 }
 
-func (i *HostInfo) RecvErrorExceeded() bool {
+// buildNetworks fills in the networks field of HostInfo. It accepts a cert.Certificate so you never ever mix the network types up.
-	if i.recvError.Add(1) >= maxRecvError {
+func (i *HostInfo) buildNetworks(myVpnNetworksTable *bart.Lite, c cert.Certificate) {
-		return true
+	if len(c.Networks()) == 1 && len(c.UnsafeNetworks()) == 0 {
-	}
+		if myVpnNetworksTable.Contains(c.Networks()[0].Addr()) {
-	return true
+			return // Simple case, no BART needed
-}
+		}
-
-func (i *HostInfo) buildNetworks(networks, unsafeNetworks []netip.Prefix) {
-	if len(networks) == 1 && len(unsafeNetworks) == 0 {
-		// Simple case, no CIDRTree needed
-		return
 	}
 
-	i.networks = new(bart.Lite)
+	i.networks = new(bart.Table[NetworkType])
-	for _, network := range networks {
+	for _, network := range c.Networks() {
-		i.networks.Insert(network)
+		nprefix := netip.PrefixFrom(network.Addr(), network.Addr().BitLen())
+		if myVpnNetworksTable.Contains(network.Addr()) {
+			i.networks.Insert(nprefix, NetworkTypeVPN)
+		} else {
+			i.networks.Insert(nprefix, NetworkTypeVPNPeer)
+		}
 	}
 
-	for _, network := range unsafeNetworks {
+	for _, network := range c.UnsafeNetworks() {
-		i.networks.Insert(network)
+		i.networks.Insert(network, NetworkTypeUnsafe)
 	}
 }
 

hostmap_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/test"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestHostMap_MakePrimary(t *testing.T) {
@@ -215,3 +216,31 @@ func TestHostMap_reload(t *testing.T) {
 	c.ReloadConfigString("preferred_ranges: [1.1.1.1/32]")
 	assert.Equal(t, []string{"1.1.1.1/32"}, toS(hm.GetPreferredRanges()))
 }
+
+func TestHostMap_RelayState(t *testing.T) {
+	h1 := &HostInfo{vpnAddrs: []netip.Addr{netip.MustParseAddr("0.0.0.1")}, localIndexId: 1}
+	a1 := netip.MustParseAddr("::1")
+	a2 := netip.MustParseAddr("2001::1")
+
+	h1.relayState.InsertRelayTo(a1)
+	assert.Equal(t, []netip.Addr{a1}, h1.relayState.relays)
+	h1.relayState.InsertRelayTo(a2)
+	assert.Equal(t, []netip.Addr{a1, a2}, h1.relayState.relays)
+	// Ensure that the first relay added is the first one returned in the copy
+	currentRelays := h1.relayState.CopyRelayIps()
+	require.Len(t, currentRelays, 2)
+	assert.Equal(t, a1, currentRelays[0])
+
+	// Deleting the last one in the list works ok
+	h1.relayState.DeleteRelay(a2)
+	assert.Equal(t, []netip.Addr{a1}, h1.relayState.relays)
+
+	// Deleting an element not in the list works ok
+	h1.relayState.DeleteRelay(a2)
+	assert.Equal(t, []netip.Addr{a1}, h1.relayState.relays)
+
+	// Deleting the only element in the list works ok
+	h1.relayState.DeleteRelay(a1)
+	assert.Equal(t, []netip.Addr{}, h1.relayState.relays)
+
+}

hostmap_tester.go

@@ -1,5 +1,4 @@
 //go:build e2e_testing
-// +build e2e_testing
 
 package nebula
 

inside.go

@@ -48,9 +48,7 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		return
 	}
 
-	hostinfo, ready := f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
+	hostinfo, ready := f.getHostinfo(packet, fwPacket)
-		hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
-	})
 
 	if hostinfo == nil {
 		f.rejectInside(packet, out, q)
@@ -66,10 +64,9 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		return
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, false, hostinfo, f.pki.GetCAPool(), localCache)
+	dropReason := f.firewall.Drop(*fwPacket, packet, false, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason == nil {
 		f.sendNoMetrics(header.Message, 0, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, packet, nb, out, q)
-
 	} else {
 		f.rejectInside(packet, out, q)
 		if f.l.Level >= logrus.DebugLevel {
@@ -81,6 +78,26 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 	}
 }
 
+func (f *Interface) getHostinfo(packet []byte, fwPacket *firewall.Packet) (*HostInfo, bool) {
+	if f.firewall.ShouldUnSNAT(fwPacket) {
+		//unsnat packet re-writing also happens here, would be nice to not,
+		//but we need to do the unsnat lookup to find the hostinfo so we can run the firewall checks
+		destVpnAddr := f.firewall.unSnat(packet, fwPacket)
+		if destVpnAddr.IsValid() {
+			//because this was a snatted packet, we know it has an on-overlay destination, so no routing should be required.
+			return f.getOrHandshakeNoRouting(destVpnAddr, func(hh *HandshakeHostInfo) {
+				hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
+			})
+		} else {
+			return nil, false
+		}
+	} else { //if we didn't need to unsnat
+		return f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
+			hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
+		})
+	}
+}
+
 func (f *Interface) rejectInside(packet []byte, out []byte, q int) {
 	if !f.firewall.InSendReject {
 		return
@@ -120,9 +137,10 @@ func (f *Interface) rejectOutside(packet []byte, ci *ConnectionState, hostinfo *
 	f.sendNoMetrics(header.Message, 0, ci, hostinfo, netip.AddrPort{}, out, nb, packet, q)
 }
 
-// Handshake will attempt to initiate a tunnel with the provided vpn address if it is within our vpn networks. This is a no-op if the tunnel is already established or being established
+// Handshake will attempt to initiate a tunnel with the provided vpn address. This is a no-op if the tunnel is already established or being established
+// it does not check if it is within our vpn networks!
 func (f *Interface) Handshake(vpnAddr netip.Addr) {
-	f.getOrHandshakeNoRouting(vpnAddr, nil)
+	f.handshakeManager.GetOrHandshake(vpnAddr, nil)
 }
 
 // getOrHandshakeNoRouting returns nil if the vpnAddr is not routable.
@@ -138,7 +156,6 @@ func (f *Interface) getOrHandshakeNoRouting(vpnAddr netip.Addr, cacheCallback fu
 // getOrHandshakeConsiderRouting will try to find the HostInfo to handle this packet, starting a handshake if necessary.
 // If the 2nd return var is false then the hostinfo is not ready to be used in a tunnel.
 func (f *Interface) getOrHandshakeConsiderRouting(fwPacket *firewall.Packet, cacheCallback func(*HandshakeHostInfo)) (*HostInfo, bool) {
-
 	destinationAddr := fwPacket.RemoteAddr
 
 	hostinfo, ready := f.getOrHandshakeNoRouting(destinationAddr, cacheCallback)
@@ -218,7 +235,7 @@ func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubTyp
 	}
 
 	// check if packet is in outbound fw rules
-	dropReason := f.firewall.Drop(*fp, false, hostinfo, f.pki.GetCAPool(), nil)
+	dropReason := f.firewall.Drop(*fp, p, false, hostinfo, f.pki.GetCAPool(), nil)
 	if dropReason != nil {
 		if f.l.Level >= logrus.DebugLevel {
 			f.l.WithField("fwPacket", fp).
@@ -231,9 +248,10 @@ func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubTyp
 	f.sendNoMetrics(header.Message, st, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, p, nb, out, 0)
 }
 
-// SendMessageToVpnAddr handles real addr:port lookup and sends to the current best known address for vpnAddr
+// SendMessageToVpnAddr handles real addr:port lookup and sends to the current best known address for vpnAddr.
+// This function ignores myVpnNetworksTable, and will always attempt to treat the address as a vpnAddr
 func (f *Interface) SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnAddr netip.Addr, p, nb, out []byte) {
-	hostInfo, ready := f.getOrHandshakeNoRouting(vpnAddr, func(hh *HandshakeHostInfo) {
+	hostInfo, ready := f.handshakeManager.GetOrHandshake(vpnAddr, func(hh *HandshakeHostInfo) {
 		hh.cachePacket(f.l, t, st, p, f.SendMessageToHostInfo, f.cachedPacketMetrics)
 	})
 
@@ -288,7 +306,7 @@ func (f *Interface) SendVia(via *HostInfo,
 	c := via.ConnectionState.messageCounter.Add(1)
 
 	out = header.Encode(out, header.Version, header.Message, header.MessageRelay, relay.RemoteIndex, c)
-	f.connectionManager.Out(via.localIndexId)
+	f.connectionManager.Out(via)
 
 	// Authenticate the header and payload, but do not encrypt for this message type.
 	// The payload consists of the inner, unencrypted Nebula header, as well as the end-to-end encrypted payload.
@@ -356,7 +374,7 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 
 	//l.WithField("trace", string(debug.Stack())).Error("out Header ", &Header{Version, t, st, 0, hostinfo.remoteIndexId, c}, p)
 	out = header.Encode(out, header.Version, t, st, hostinfo.remoteIndexId, c)
-	f.connectionManager.Out(hostinfo.localIndexId)
+	f.connectionManager.Out(hostinfo)
 
 	// Query our LH if we haven't since the last time we've been rebound, this will cause the remote to punch against
 	// all our addrs and enable a faster roaming.

inside_bsd.go

@@ -1,5 +1,4 @@
 //go:build darwin || dragonfly || freebsd || netbsd || openbsd
-// +build darwin dragonfly freebsd netbsd openbsd
 
 package nebula
 

inside_generic.go

@@ -1,5 +1,4 @@
 //go:build !darwin && !dragonfly && !freebsd && !netbsd && !openbsd
-// +build !darwin,!dragonfly,!freebsd,!netbsd,!openbsd
 
 package nebula
 

interface.go

@@ -24,23 +24,23 @@ import (
 const mtu = 9001
 
 type InterfaceConfig struct {
-	HostMap                 *HostMap
+	HostMap            *HostMap
-	Outside                 udp.Conn
+	Outside            udp.Conn
-	Inside                  overlay.Device
+	Inside             overlay.Device
-	pki                     *PKI
+	pki                *PKI
-	Firewall                *Firewall
+	Cipher             string
-	ServeDns                bool
+	Firewall           *Firewall
-	HandshakeManager        *HandshakeManager
+	ServeDns           bool
-	lightHouse              *LightHouse
+	HandshakeManager   *HandshakeManager
-	checkInterval           time.Duration
+	lightHouse         *LightHouse
-	pendingDeletionInterval time.Duration
+	connectionManager  *connectionManager
-	DropLocalBroadcast      bool
+	DropLocalBroadcast bool
-	DropMulticast           bool
+	DropMulticast      bool
-	routines                int
+	routines           int
-	MessageMetrics          *MessageMetrics
+	MessageMetrics     *MessageMetrics
-	version                 string
+	version            string
-	relayManager            *relayManager
+	relayManager       *relayManager
-	punchy                  *Punchy
+	punchy             *Punchy
 
 	tryPromoteEvery uint32
 	reQueryEvery    uint32
@@ -77,7 +77,8 @@ type Interface struct {
 	reQueryEvery    atomic.Uint32
 	reQueryWait     atomic.Int64
 
-	sendRecvErrorConfig sendRecvErrorConfig
+	sendRecvErrorConfig   recvErrorConfig
+	acceptRecvErrorConfig recvErrorConfig
 
 	// rebindCount is used to decide if an active tunnel should trigger a punch notification through a lighthouse
 	rebindCount int8
@@ -110,34 +111,34 @@ type EncWriter interface {
 	GetCertState() *CertState
 }
 
-type sendRecvErrorConfig uint8
+type recvErrorConfig uint8
 
 const (
-	sendRecvErrorAlways sendRecvErrorConfig = iota
+	recvErrorAlways recvErrorConfig = iota
-	sendRecvErrorNever
+	recvErrorNever
-	sendRecvErrorPrivate
+	recvErrorPrivate
 )
 
-func (s sendRecvErrorConfig) ShouldSendRecvError(endpoint netip.AddrPort) bool {
+func (s recvErrorConfig) ShouldRecvError(endpoint netip.AddrPort) bool {
 	switch s {
-	case sendRecvErrorPrivate:
+	case recvErrorPrivate:
 		return endpoint.Addr().IsPrivate()
-	case sendRecvErrorAlways:
+	case recvErrorAlways:
 		return true
-	case sendRecvErrorNever:
+	case recvErrorNever:
 		return false
 	default:
-		panic(fmt.Errorf("invalid sendRecvErrorConfig value: %d", s))
+		panic(fmt.Errorf("invalid recvErrorConfig value: %d", s))
 	}
 }
 
-func (s sendRecvErrorConfig) String() string {
+func (s recvErrorConfig) String() string {
 	switch s {
-	case sendRecvErrorAlways:
+	case recvErrorAlways:
 		return "always"
-	case sendRecvErrorNever:
+	case recvErrorNever:
 		return "never"
-	case sendRecvErrorPrivate:
+	case recvErrorPrivate:
 		return "private"
 	default:
 		return fmt.Sprintf("invalid(%d)", s)
@@ -157,6 +158,9 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 	if c.Firewall == nil {
 		return nil, errors.New("no firewall rules")
 	}
+	if c.connectionManager == nil {
+		return nil, errors.New("no connection manager")
+	}
 
 	cs := c.pki.getCertState()
 	ifce := &Interface{
@@ -181,7 +185,7 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 		myVpnAddrsTable:       cs.myVpnAddrsTable,
 		myBroadcastAddrsTable: cs.myVpnBroadcastAddrsTable,
 		relayManager:          c.relayManager,
-
+		connectionManager:     c.connectionManager,
 		conntrackCacheTimeout: c.ConntrackCacheTimeout,
 
 		metricHandshakes: metrics.GetOrRegisterHistogram("handshakes", nil, metrics.NewExpDecaySample(1028, 0.015)),
@@ -198,7 +202,7 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 	ifce.reQueryEvery.Store(c.reQueryEvery)
 	ifce.reQueryWait.Store(int64(c.reQueryWait))
 
-	ifce.connectionManager = newConnectionManager(ctx, c.l, ifce, c.checkInterval, c.pendingDeletionInterval, c.punchy)
+	ifce.connectionManager.intf = ifce
 
 	return ifce, nil
 }
@@ -219,6 +223,13 @@ func (f *Interface) activate() {
 		WithField("boringcrypto", boringEnabled()).
 		Info("Nebula interface is active")
 
+	if f.routines > 1 {
+		if !f.inside.SupportsMultiqueue() || !f.outside.SupportsMultipleReaders() {
+			f.routines = 1
+			f.l.Warn("routines is not supported on this platform, falling back to a single routine")
+		}
+	}
+
 	metrics.GetOrRegisterGauge("routines", nil).Update(int64(f.routines))
 
 	// Prepare n tun queues
@@ -237,6 +248,7 @@ func (f *Interface) activate() {
 		f.inside.Close()
 		f.l.Fatal(err)
 	}
+	f.firewall.SetSNATAddressFromInterface(f)
 }
 
 func (f *Interface) run() {
@@ -269,7 +281,7 @@ func (f *Interface) listenOut(i int) {
 	nb := make([]byte, 12, 12)
 
 	li.ListenOut(func(fromUdpAddr netip.AddrPort, payload []byte) {
-		f.readOutsidePackets(fromUdpAddr, nil, plaintext[:0], payload, h, fwPacket, lhh, nb, i, ctCache.Get(f.l))
+		f.readOutsidePackets(ViaSender{UdpAddr: fromUdpAddr}, plaintext[:0], payload, h, fwPacket, lhh, nb, i, ctCache.Get(f.l))
 	})
 }
 
@@ -302,6 +314,7 @@ func (f *Interface) listenIn(reader io.ReadWriteCloser, i int) {
 func (f *Interface) RegisterConfigChangeCallbacks(c *config.C) {
 	c.RegisterReloadCallback(f.reloadFirewall)
 	c.RegisterReloadCallback(f.reloadSendRecvError)
+	c.RegisterReloadCallback(f.reloadAcceptRecvError)
 	c.RegisterReloadCallback(f.reloadDisconnectInvalid)
 	c.RegisterReloadCallback(f.reloadMisc)
 
@@ -332,6 +345,7 @@ func (f *Interface) reloadFirewall(c *config.C) {
 		f.l.WithError(err).Error("Error while creating firewall during reload")
 		return
 	}
+	fw.SetSNATAddressFromInterface(f)
 
 	oldFw := f.firewall
 	conntrack := oldFw.Conntrack
@@ -365,16 +379,16 @@ func (f *Interface) reloadSendRecvError(c *config.C) {
 
 		switch stringValue {
 		case "always":
-			f.sendRecvErrorConfig = sendRecvErrorAlways
+			f.sendRecvErrorConfig = recvErrorAlways
 		case "never":
-			f.sendRecvErrorConfig = sendRecvErrorNever
+			f.sendRecvErrorConfig = recvErrorNever
 		case "private":
-			f.sendRecvErrorConfig = sendRecvErrorPrivate
+			f.sendRecvErrorConfig = recvErrorPrivate
 		default:
 			if c.GetBool("listen.send_recv_error", true) {
-				f.sendRecvErrorConfig = sendRecvErrorAlways
+				f.sendRecvErrorConfig = recvErrorAlways
 			} else {
-				f.sendRecvErrorConfig = sendRecvErrorNever
+				f.sendRecvErrorConfig = recvErrorNever
 			}
 		}
 
@@ -383,6 +397,30 @@ func (f *Interface) reloadSendRecvError(c *config.C) {
 	}
 }
 
+func (f *Interface) reloadAcceptRecvError(c *config.C) {
+	if c.InitialLoad() || c.HasChanged("listen.accept_recv_error") {
+		stringValue := c.GetString("listen.accept_recv_error", "always")
+
+		switch stringValue {
+		case "always":
+			f.acceptRecvErrorConfig = recvErrorAlways
+		case "never":
+			f.acceptRecvErrorConfig = recvErrorNever
+		case "private":
+			f.acceptRecvErrorConfig = recvErrorPrivate
+		default:
+			if c.GetBool("listen.accept_recv_error", true) {
+				f.acceptRecvErrorConfig = recvErrorAlways
+			} else {
+				f.acceptRecvErrorConfig = recvErrorNever
+			}
+		}
+
+		f.l.WithField("acceptRecvError", f.acceptRecvErrorConfig.String()).
+			Info("Loaded accept_recv_error config")
+	}
+}
+
 func (f *Interface) reloadMisc(c *config.C) {
 	if c.HasChanged("counters.try_promote") {
 		n := c.GetUint32("counters.try_promote", defaultPromoteEvery)
@@ -454,6 +492,14 @@ func (f *Interface) Close() error {
 			f.l.WithError(err).Error("Error while closing udp socket")
 		}
 	}
+	for i, r := range f.readers {
+		if i == 0 {
+			continue // f.readers[0] is f.inside, which we want to save for last
+		}
+		if err := r.Close(); err != nil {
+			f.l.WithError(err).Error("Error while closing tun reader")
+		}
+	}
 
 	// Release the tun device
 	return f.inside.Close()

lighthouse.go

@@ -24,6 +24,7 @@ import (
 )
 
 var ErrHostNotKnown = errors.New("host not known")
+var ErrBadDetailsVpnAddr = errors.New("invalid packet, malformed detailsVpnAddr")
 
 type LightHouse struct {
 	//TODO: We need a timer wheel to kick out vpnAddrs that haven't reported in a long time
@@ -56,7 +57,7 @@ type LightHouse struct {
 	// staticList exists to avoid having a bool in each addrMap entry
 	// since static should be rare
 	staticList  atomic.Pointer[map[netip.Addr]struct{}]
-	lighthouses atomic.Pointer[map[netip.Addr]struct{}]
+	lighthouses atomic.Pointer[[]netip.Addr]
 
 	interval     atomic.Int64
 	updateCancel context.CancelFunc
@@ -107,7 +108,7 @@ func NewLightHouseFromConfig(ctx context.Context, l *logrus.Logger, c *config.C,
 		queryChan:          make(chan netip.Addr, c.GetUint32("handshakes.query_buffer", 64)),
 		l:                  l,
 	}
-	lighthouses := make(map[netip.Addr]struct{})
+	lighthouses := make([]netip.Addr, 0)
 	h.lighthouses.Store(&lighthouses)
 	staticList := make(map[netip.Addr]struct{})
 	h.staticList.Store(&staticList)
@@ -143,7 +144,7 @@ func (lh *LightHouse) GetStaticHostList() map[netip.Addr]struct{} {
 	return *lh.staticList.Load()
 }
 
-func (lh *LightHouse) GetLighthouses() map[netip.Addr]struct{} {
+func (lh *LightHouse) GetLighthouses() []netip.Addr {
 	return *lh.lighthouses.Load()
 }
 
@@ -306,13 +307,12 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	}
 
 	if initial || c.HasChanged("lighthouse.hosts") {
-		lhMap := make(map[netip.Addr]struct{})
+		lhList, err := lh.parseLighthouses(c)
-		err := lh.parseLighthouses(c, lhMap)
 		if err != nil {
 			return err
 		}
 
-		lh.lighthouses.Store(&lhMap)
+		lh.lighthouses.Store(&lhList)
 		if !initial {
 			//NOTE: we are not tearing down existing lighthouse connections because they might be used for non lighthouse traffic
 			lh.l.Info("lighthouse.hosts has changed")
@@ -346,36 +346,38 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	return nil
 }
 
-func (lh *LightHouse) parseLighthouses(c *config.C, lhMap map[netip.Addr]struct{}) error {
+func (lh *LightHouse) parseLighthouses(c *config.C) ([]netip.Addr, error) {
 	lhs := c.GetStringSlice("lighthouse.hosts", []string{})
 	if lh.amLighthouse && len(lhs) != 0 {
 		lh.l.Warn("lighthouse.am_lighthouse enabled on node but upstream lighthouses exist in config")
 	}
+	out := make([]netip.Addr, len(lhs))
 
 	for i, host := range lhs {
 		addr, err := netip.ParseAddr(host)
 		if err != nil {
-			return util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
+			return nil, util.NewContextualError("Unable to parse lighthouse host entry", m{"host": host, "entry": i + 1}, err)
 		}
 
 		if !lh.myVpnNetworksTable.Contains(addr) {
-			return util.NewContextualError("lighthouse host is not in our networks, invalid", m{"vpnAddr": addr, "networks": lh.myVpnNetworks}, nil)
+			lh.l.WithFields(m{"vpnAddr": addr, "networks": lh.myVpnNetworks}).
+				Warn("lighthouse host is not within our networks, lighthouse functionality will work but layer 3 network traffic to the lighthouse will not")
 		}
-		lhMap[addr] = struct{}{}
+		out[i] = addr
 	}
 
-	if !lh.amLighthouse && len(lhMap) == 0 {
+	if !lh.amLighthouse && len(out) == 0 {
 		lh.l.Warn("No lighthouse.hosts configured, this host will only be able to initiate tunnels with static_host_map entries")
 	}
 
 	staticList := lh.GetStaticHostList()
-	for lhAddr, _ := range lhMap {
+	for i := range out {
-		if _, ok := staticList[lhAddr]; !ok {
+		if _, ok := staticList[out[i]]; !ok {
-			return fmt.Errorf("lighthouse %s does not have a static_host_map entry", lhAddr)
+			return nil, fmt.Errorf("lighthouse %s does not have a static_host_map entry", out[i])
 		}
 	}
 
-	return nil
+	return out, nil
 }
 
 func getStaticMapCadence(c *config.C) (time.Duration, error) {
@@ -430,7 +432,8 @@ func (lh *LightHouse) loadStaticMap(c *config.C, staticList map[netip.Addr]struc
 		}
 
 		if !lh.myVpnNetworksTable.Contains(vpnAddr) {
-			return util.NewContextualError("static_host_map key is not in our network, invalid", m{"vpnAddr": vpnAddr, "networks": lh.myVpnNetworks, "entry": i + 1}, nil)
+			lh.l.WithFields(m{"vpnAddr": vpnAddr, "networks": lh.myVpnNetworks, "entry": i + 1}).
+				Warn("static_host_map key is not within our networks, layer 3 network traffic to this host will not work")
 		}
 
 		vals, ok := v.([]any)
@@ -486,7 +489,7 @@ func (lh *LightHouse) QueryCache(vpnAddrs []netip.Addr) *RemoteList {
 	lh.Lock()
 	defer lh.Unlock()
 	// Add an entry if we don't already have one
-	return lh.unlockedGetRemoteList(vpnAddrs)
+	return lh.unlockedGetRemoteList(vpnAddrs) //todo CERT-V2 this contains addrmap lookups we could potentially skip
 }
 
 // queryAndPrepMessage is a lock helper on RemoteList, assisting the caller to build a lighthouse message containing
@@ -519,11 +522,15 @@ func (lh *LightHouse) queryAndPrepMessage(vpnAddr netip.Addr, f func(*cache) (in
 }
 
 func (lh *LightHouse) DeleteVpnAddrs(allVpnAddrs []netip.Addr) {
-	// First we check the static mapping
+	// First we check the static host map. If any of the VpnAddrs to be deleted are present, do nothing.
-	// and do nothing if it is there
+	staticList := lh.GetStaticHostList()
-	if _, ok := lh.GetStaticHostList()[allVpnAddrs[0]]; ok {
+	for _, addr := range allVpnAddrs {
-		return
+		if _, ok := staticList[addr]; ok {
+			return
+		}
 	}
+
+	// None of the VpnAddrs were present. Now we can do the deletes.
 	lh.Lock()
 	rm, ok := lh.addrMap[allVpnAddrs[0]]
 	if ok {
@@ -565,7 +572,7 @@ func (lh *LightHouse) addStaticRemotes(i int, d time.Duration, network string, t
 	am.unlockedSetHostnamesResults(hr)
 
 	for _, addrPort := range hr.GetAddrs() {
-		if !lh.shouldAdd(vpnAddr, addrPort.Addr()) {
+		if !lh.shouldAdd([]netip.Addr{vpnAddr}, addrPort.Addr()) {
 			continue
 		}
 		switch {
@@ -627,23 +634,30 @@ func (lh *LightHouse) addCalculatedRemotes(vpnAddr netip.Addr) bool {
 	return len(calculatedV4) > 0 || len(calculatedV6) > 0
 }
 
-// unlockedGetRemoteList
+// unlockedGetRemoteList assumes you have the lh lock
-// assumes you have the lh lock
 func (lh *LightHouse) unlockedGetRemoteList(allAddrs []netip.Addr) *RemoteList {
-	am, ok := lh.addrMap[allAddrs[0]]
+	// before we go and make a new remotelist, we need to make sure we don't have one for any of this set of vpnaddrs yet
-	if !ok {
+	for i, addr := range allAddrs {
-		am = NewRemoteList(allAddrs, func(a netip.Addr) bool { return lh.shouldAdd(allAddrs[0], a) })
+		am, ok := lh.addrMap[addr]
-		for _, addr := range allAddrs {
+		if ok {
-			lh.addrMap[addr] = am
+			if i != 0 {
+				lh.addrMap[allAddrs[0]] = am
+			}
+			return am
 		}
 	}
+
+	am := NewRemoteList(allAddrs, lh.shouldAdd)
+	for _, addr := range allAddrs {
+		lh.addrMap[addr] = am
+	}
 	return am
 }
 
-func (lh *LightHouse) shouldAdd(vpnAddr netip.Addr, to netip.Addr) bool {
+func (lh *LightHouse) shouldAdd(vpnAddrs []netip.Addr, to netip.Addr) bool {
-	allow := lh.GetRemoteAllowList().Allow(vpnAddr, to)
+	allow := lh.GetRemoteAllowList().AllowAll(vpnAddrs, to)
 	if lh.l.Level >= logrus.TraceLevel {
-		lh.l.WithField("vpnAddr", vpnAddr).WithField("udpAddr", to).WithField("allow", allow).
+		lh.l.WithField("vpnAddrs", vpnAddrs).WithField("udpAddr", to).WithField("allow", allow).
 			Trace("remoteAllowList.Allow")
 	}
 	if !allow {
@@ -698,18 +712,14 @@ func (lh *LightHouse) unlockedShouldAddV6(vpnAddr netip.Addr, to *V6AddrPort) bo
 }
 
 func (lh *LightHouse) IsLighthouseAddr(vpnAddr netip.Addr) bool {
-	if _, ok := lh.GetLighthouses()[vpnAddr]; ok {
+	l := lh.GetLighthouses()
-		return true
+	return slices.Contains(l, vpnAddr)
-	}
-	return false
 }
 
-// TODO: CERT-V2 IsLighthouseAddr should be sufficient, we just need to update the vpnAddrs for lighthouses after a handshake
+func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddrs []netip.Addr) bool {
-// so that we know all the lighthouse vpnAddrs, not just the ones we were configured to talk to initially
-func (lh *LightHouse) IsAnyLighthouseAddr(vpnAddr []netip.Addr) bool {
 	l := lh.GetLighthouses()
-	for _, a := range vpnAddr {
+	for i := range vpnAddrs {
-		if _, ok := l[a]; ok {
+		if slices.Contains(l, vpnAddrs[i]) {
 			return true
 		}
 	}
@@ -752,7 +762,7 @@ func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
 	queried := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
 			v = hi.ConnectionState.myCert.Version()
@@ -870,7 +880,7 @@ func (lh *LightHouse) SendUpdate() {
 	updated := 0
 	lighthouses := lh.GetLighthouses()
 
-	for lhVpnAddr := range lighthouses {
+	for _, lhVpnAddr := range lighthouses {
 		var v cert.Version
 		hi := lh.ifce.GetHostInfo(lhVpnAddr)
 		if hi != nil {
@@ -928,7 +938,6 @@ func (lh *LightHouse) SendUpdate() {
 						V4AddrPorts:   v4,
 						V6AddrPorts:   v6,
 						RelayVpnAddrs: relays,
-						VpnAddr:       netAddrToProtoAddr(lh.myVpnNetworks[0].Addr()),
 					},
 				}
 
@@ -1048,19 +1057,19 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 		return
 	}
 
-	useVersion := cert.Version1
+	queryVpnAddr, useVersion, err := n.Details.GetVpnAddrAndVersion()
-	var queryVpnAddr netip.Addr
+	if err != nil {
-	if n.Details.OldVpnAddr != 0 {
-		b := [4]byte{}
-		binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
-		queryVpnAddr = netip.AddrFrom4(b)
-		useVersion = 1
-	} else if n.Details.VpnAddr != nil {
-		queryVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
-		useVersion = 2
-	} else {
 		if lhh.l.Level >= logrus.DebugLevel {
-			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).Debugln("Dropping malformed HostQuery")
+			lhh.l.WithField("from", fromVpnAddrs).WithField("details", n.Details).
+				Debugln("Dropping malformed HostQuery")
+		}
+		return
+	}
+	if useVersion == cert.Version1 && queryVpnAddr.Is6() {
+		// this case really shouldn't be possible to represent, but reject it anyway.
+		if lhh.l.Level >= logrus.DebugLevel {
+			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("queryVpnAddr", queryVpnAddr).
+				Debugln("invalid vpn addr for v1 handleHostQuery")
 		}
 		return
 	}
@@ -1069,9 +1078,6 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 		n = lhh.resetMeta()
 		n.Type = NebulaMeta_HostQueryReply
 		if useVersion == cert.Version1 {
-			if !queryVpnAddr.Is4() {
-				return 0, fmt.Errorf("invalid vpn addr for v1 handleHostQuery")
-			}
 			b := queryVpnAddr.As4()
 			n.Details.OldVpnAddr = binary.BigEndian.Uint32(b[:])
 		} else {
@@ -1116,8 +1122,9 @@ func (lhh *LightHouseHandler) sendHostPunchNotification(n *NebulaMeta, fromVpnAd
 			if ok {
 				whereToPunch = newDest
 			} else {
-				//TODO: CERT-V2 this means the destination will have no addresses in common with the punch-ee
+				if lhh.l.Level >= logrus.DebugLevel {
-				//choosing to do nothing for now, but maybe we return an error?
+					lhh.l.WithField("to", crt.Networks()).Debugln("unable to punch to host, no addresses in common")
+				}
 			}
 		}
 
@@ -1176,19 +1183,17 @@ func (lhh *LightHouseHandler) coalesceAnswers(v cert.Version, c *cache, n *Nebul
 				if !r.Is4() {
 					continue
 				}
-
 				b = r.As4()
 				n.Details.OldRelayVpnAddrs = append(n.Details.OldRelayVpnAddrs, binary.BigEndian.Uint32(b[:]))
 			}
-
 		} else if v == cert.Version2 {
 			for _, r := range c.relay.relay {
 				n.Details.RelayVpnAddrs = append(n.Details.RelayVpnAddrs, netAddrToProtoAddr(r))
 			}
-
 		} else {
-			//TODO: CERT-V2 don't panic
+			if lhh.l.Level >= logrus.DebugLevel {
-			panic("unsupported version")
+				lhh.l.WithField("version", v).Debug("unsupported protocol version")
+			}
 		}
 	}
 }
@@ -1198,18 +1203,16 @@ func (lhh *LightHouseHandler) handleHostQueryReply(n *NebulaMeta, fromVpnAddrs [
 		return
 	}
 
-	lhh.lh.Lock()
+	certVpnAddr, _, err := n.Details.GetVpnAddrAndVersion()
-
+	if err != nil {
-	var certVpnAddr netip.Addr
+		if lhh.l.Level >= logrus.DebugLevel {
-	if n.Details.OldVpnAddr != 0 {
+			lhh.l.WithError(err).WithField("vpnAddrs", fromVpnAddrs).Error("dropping malformed HostQueryReply")
-		b := [4]byte{}
+		}
-		binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
+		return
-		certVpnAddr = netip.AddrFrom4(b)
-	} else if n.Details.VpnAddr != nil {
-		certVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
 	}
 	relays := n.Details.GetRelays()
 
+	lhh.lh.Lock()
 	am := lhh.lh.unlockedGetRemoteList([]netip.Addr{certVpnAddr})
 	am.Lock()
 	lhh.lh.Unlock()
@@ -1234,27 +1237,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 		return
 	}
 
+	// not using GetVpnAddrAndVersion because we don't want to error on a blank detailsVpnAddr
 	var detailsVpnAddr netip.Addr
-	useVersion := cert.Version1
+	var useVersion cert.Version
-	if n.Details.OldVpnAddr != 0 {
+	if n.Details.OldVpnAddr != 0 { //v1 always sets this field
 		b := [4]byte{}
 		binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
 		detailsVpnAddr = netip.AddrFrom4(b)
 		useVersion = cert.Version1
-	} else if n.Details.VpnAddr != nil {
+	} else if n.Details.VpnAddr != nil { //this field is "optional" in v2, but if it's set, we should enforce it
 		detailsVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
 		useVersion = cert.Version2
 	} else {
-		if lhh.l.Level >= logrus.DebugLevel {
+		detailsVpnAddr = netip.Addr{}
-			lhh.l.WithField("details", n.Details).Debugf("dropping invalid HostUpdateNotification")
+		useVersion = cert.Version2
-		}
-		return
 	}
 
-	//TODO: CERT-V2 hosts with only v2 certs cannot provide their ipv6 addr when contacting the lighthouse via v4?
+	//Simple check that the host sent this not someone else, if detailsVpnAddr is filled
-	//TODO: CERT-V2 why do we care about the vpnAddr in the packet? We know where it came from, right?
+	if detailsVpnAddr.IsValid() && !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
-	//Simple check that the host sent this not someone else
-	if !slices.Contains(fromVpnAddrs, detailsVpnAddr) {
 		if lhh.l.Level >= logrus.DebugLevel {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).WithField("answer", detailsVpnAddr).Debugln("Host sent invalid update")
 		}
@@ -1268,24 +1268,24 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 	am.Lock()
 	lhh.lh.Unlock()
 
-	am.unlockedSetV4(fromVpnAddrs[0], detailsVpnAddr, n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
+	am.unlockedSetV4(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V4AddrPorts, lhh.lh.unlockedShouldAddV4)
-	am.unlockedSetV6(fromVpnAddrs[0], detailsVpnAddr, n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
+	am.unlockedSetV6(fromVpnAddrs[0], fromVpnAddrs[0], n.Details.V6AddrPorts, lhh.lh.unlockedShouldAddV6)
 	am.unlockedSetRelay(fromVpnAddrs[0], relays)
 	am.Unlock()
 
 	n = lhh.resetMeta()
 	n.Type = NebulaMeta_HostUpdateNotificationAck
-
+	switch useVersion {
-	if useVersion == cert.Version1 {
+	case cert.Version1:
 		if !fromVpnAddrs[0].Is4() {
 			lhh.l.WithField("vpnAddrs", fromVpnAddrs).Error("Can not send HostUpdateNotificationAck for a ipv6 vpn ip in a v1 message")
 			return
 		}
 		vpnAddrB := fromVpnAddrs[0].As4()
 		n.Details.OldVpnAddr = binary.BigEndian.Uint32(vpnAddrB[:])
-	} else if useVersion == cert.Version2 {
+	case cert.Version2:
-		n.Details.VpnAddr = netAddrToProtoAddr(fromVpnAddrs[0])
+		// do nothing, we want to send a blank message
-	} else {
+	default:
 		lhh.l.WithField("useVersion", useVersion).Error("invalid protocol version")
 		return
 	}
@@ -1303,13 +1303,20 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpnAddrs []netip.Addr, w EncWriter) {
 	//It's possible the lighthouse is communicating with us using a non primary vpn addr,
 	//which means we need to compare all fromVpnAddrs against all configured lighthouse vpn addrs.
-	//maybe one day we'll have a better idea, if it matters.
 	if !lhh.lh.IsAnyLighthouseAddr(fromVpnAddrs) {
 		return
 	}
 
+	detailsVpnAddr, _, err := n.Details.GetVpnAddrAndVersion()
+	if err != nil {
+		if lhh.l.Level >= logrus.DebugLevel {
+			lhh.l.WithField("details", n.Details).WithError(err).Debugln("dropping invalid HostPunchNotification")
+		}
+		return
+	}
+
 	empty := []byte{0}
-	punch := func(vpnPeer netip.AddrPort) {
+	punch := func(vpnPeer netip.AddrPort, logVpnAddr netip.Addr) {
 		if !vpnPeer.IsValid() {
 			return
 		}
@@ -1321,48 +1328,38 @@ func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpn
 		}()
 
 		if lhh.l.Level >= logrus.DebugLevel {
-			var logVpnAddr netip.Addr
-			if n.Details.OldVpnAddr != 0 {
-				b := [4]byte{}
-				binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
-				logVpnAddr = netip.AddrFrom4(b)
-			} else if n.Details.VpnAddr != nil {
-				logVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
-			}
 			lhh.l.Debugf("Punching on %v for %v", vpnPeer, logVpnAddr)
 		}
 	}
 
+	remoteAllowList := lhh.lh.GetRemoteAllowList()
 	for _, a := range n.Details.V4AddrPorts {
-		punch(protoV4AddrPortToNetAddrPort(a))
+		b := protoV4AddrPortToNetAddrPort(a)
+		if remoteAllowList.Allow(detailsVpnAddr, b.Addr()) {
+			punch(b, detailsVpnAddr)
+		}
 	}
 
 	for _, a := range n.Details.V6AddrPorts {
-		punch(protoV6AddrPortToNetAddrPort(a))
+		b := protoV6AddrPortToNetAddrPort(a)
+		if remoteAllowList.Allow(detailsVpnAddr, b.Addr()) {
+			punch(b, detailsVpnAddr)
+		}
 	}
 
 	// This sends a nebula test packet to the host trying to contact us. In the case
 	// of a double nat or other difficult scenario, this may help establish
 	// a tunnel.
 	if lhh.lh.punchy.GetRespond() {
-		var queryVpnAddr netip.Addr
-		if n.Details.OldVpnAddr != 0 {
-			b := [4]byte{}
-			binary.BigEndian.PutUint32(b[:], n.Details.OldVpnAddr)
-			queryVpnAddr = netip.AddrFrom4(b)
-		} else if n.Details.VpnAddr != nil {
-			queryVpnAddr = protoAddrToNetAddr(n.Details.VpnAddr)
-		}
-
 		go func() {
 			time.Sleep(lhh.lh.punchy.GetRespondDelay())
 			if lhh.l.Level >= logrus.DebugLevel {
-				lhh.l.Debugf("Sending a nebula test packet to vpn addr %s", queryVpnAddr)
+				lhh.l.Debugf("Sending a nebula test packet to vpn addr %s", detailsVpnAddr)
 			}
 			//NOTE: we have to allocate a new output buffer here since we are spawning a new goroutine
 			// for each punchBack packet. We should move this into a timerwheel or a single goroutine
 			// managed by a channel.
-			w.SendMessageToVpnAddr(header.Test, header.TestRequest, queryVpnAddr, []byte(""), make([]byte, 12, 12), make([]byte, mtu))
+			w.SendMessageToVpnAddr(header.Test, header.TestRequest, detailsVpnAddr, []byte(""), make([]byte, 12, 12), make([]byte, mtu))
 		}()
 	}
 }
@@ -1441,3 +1438,17 @@ func findNetworkUnion(prefixes []netip.Prefix, addrs []netip.Addr) (netip.Addr,
 	}
 	return netip.Addr{}, false
 }
+
+func (d *NebulaMetaDetails) GetVpnAddrAndVersion() (netip.Addr, cert.Version, error) {
+	if d.OldVpnAddr != 0 {
+		b := [4]byte{}
+		binary.BigEndian.PutUint32(b[:], d.OldVpnAddr)
+		detailsVpnAddr := netip.AddrFrom4(b)
+		return detailsVpnAddr, cert.Version1, nil
+	} else if d.VpnAddr != nil {
+		detailsVpnAddr := protoAddrToNetAddr(d.VpnAddr)
+		return detailsVpnAddr, cert.Version2, nil
+	} else {
+		return netip.Addr{}, cert.Version1, ErrBadDetailsVpnAddr
+	}
+}

lighthouse_test.go

@@ -1,7 +1,6 @@
 package nebula
 
 import (
-	"context"
 	"encoding/binary"
 	"fmt"
 	"net/netip"
@@ -14,7 +13,7 @@ import (
 	"github.com/slackhq/nebula/test"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"gopkg.in/yaml.v3"
+	"go.yaml.in/yaml/v3"
 )
 
 func TestOldIPv4Only(t *testing.T) {
@@ -42,14 +41,14 @@ func Test_lhStaticMapping(t *testing.T) {
 	c := config.NewC(l)
 	c.Settings["lighthouse"] = map[string]any{"hosts": []any{lh1}}
 	c.Settings["static_host_map"] = map[string]any{lh1: []any{"1.1.1.1:4242"}}
-	_, err := NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	_, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
 	require.NoError(t, err)
 
 	lh2 := "10.128.0.3"
 	c = config.NewC(l)
 	c.Settings["lighthouse"] = map[string]any{"hosts": []any{lh1, lh2}}
 	c.Settings["static_host_map"] = map[string]any{lh1: []any{"100.1.1.1:4242"}}
-	_, err = NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	_, err = NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
 	require.EqualError(t, err, "lighthouse 10.128.0.3 does not have a static_host_map entry")
 }
 
@@ -71,7 +70,7 @@ func TestReloadLighthouseInterval(t *testing.T) {
 	}
 
 	c.Settings["static_host_map"] = map[string]any{lh1: []any{"1.1.1.1:4242"}}
-	lh, err := NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	lh, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
 	require.NoError(t, err)
 	lh.ifce = &mockEncWriter{}
 
@@ -99,7 +98,7 @@ func BenchmarkLighthouseHandleRequest(b *testing.B) {
 	}
 
 	c := config.NewC(l)
-	lh, err := NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	lh, err := NewLightHouseFromConfig(b.Context(), l, c, cs, nil, nil)
 	require.NoError(b, err)
 
 	hAddr := netip.MustParseAddrPort("4.5.6.7:12345")
@@ -202,7 +201,7 @@ func TestLighthouse_Memory(t *testing.T) {
 		myVpnNetworks:      []netip.Prefix{myVpnNet},
 		myVpnNetworksTable: nt,
 	}
-	lh, err := NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	lh, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
 	lh.ifce = &mockEncWriter{}
 	require.NoError(t, err)
 	lhh := lh.NewRequestHandler()
@@ -288,7 +287,7 @@ func TestLighthouse_reload(t *testing.T) {
 		myVpnNetworksTable: nt,
 	}
 
-	lh, err := NewLightHouseFromConfig(context.Background(), l, c, cs, nil, nil)
+	lh, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
 	require.NoError(t, err)
 
 	nc := map[string]any{
@@ -493,3 +492,123 @@ func Test_findNetworkUnion(t *testing.T) {
 	out, ok = findNetworkUnion([]netip.Prefix{fc00}, []netip.Addr{a1, afe81})
 	assert.False(t, ok)
 }
+
+func TestLighthouse_Dont_Delete_Static_Hosts(t *testing.T) {
+	l := test.NewLogger()
+
+	myUdpAddr2 := netip.MustParseAddrPort("1.2.3.4:4242")
+
+	testSameHostNotStatic := netip.MustParseAddr("10.128.0.41")
+	testStaticHost := netip.MustParseAddr("10.128.0.42")
+	//myVpnIp := netip.MustParseAddr("10.128.0.2")
+
+	c := config.NewC(l)
+	lh1 := "10.128.0.2"
+	c.Settings["lighthouse"] = map[string]any{
+		"hosts":    []any{lh1},
+		"interval": "1s",
+	}
+
+	c.Settings["listen"] = map[string]any{"port": 4242}
+	c.Settings["static_host_map"] = map[string]any{
+		lh1:           []any{"1.1.1.1:4242"},
+		"10.128.0.42": []any{"1.2.3.4:4242"},
+	}
+
+	myVpnNet := netip.MustParsePrefix("10.128.0.1/24")
+	nt := new(bart.Lite)
+	nt.Insert(myVpnNet)
+	cs := &CertState{
+		myVpnNetworks:      []netip.Prefix{myVpnNet},
+		myVpnNetworksTable: nt,
+	}
+	lh, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
+	require.NoError(t, err)
+	lh.ifce = &mockEncWriter{}
+
+	//test that we actually have the static entry:
+	out := lh.Query(testStaticHost)
+	assert.NotNil(t, out)
+	assert.Equal(t, out.vpnAddrs[0], testStaticHost)
+	out.Rebuild([]netip.Prefix{}) //why tho
+	assert.Equal(t, out.addrs[0], myUdpAddr2)
+
+	//bolt on a lower numbered primary IP
+	am := lh.unlockedGetRemoteList([]netip.Addr{testStaticHost})
+	am.vpnAddrs = []netip.Addr{testSameHostNotStatic, testStaticHost}
+	lh.addrMap[testSameHostNotStatic] = am
+	out.Rebuild([]netip.Prefix{}) //???
+
+	//test that we actually have the static entry:
+	out = lh.Query(testStaticHost)
+	assert.NotNil(t, out)
+	assert.Equal(t, out.vpnAddrs[0], testSameHostNotStatic)
+	assert.Equal(t, out.vpnAddrs[1], testStaticHost)
+	assert.Equal(t, out.addrs[0], myUdpAddr2)
+
+	//test that we actually have the static entry for BOTH:
+	out2 := lh.Query(testSameHostNotStatic)
+	assert.Same(t, out2, out)
+
+	//now do the delete
+	lh.DeleteVpnAddrs([]netip.Addr{testSameHostNotStatic, testStaticHost})
+	//verify
+	out = lh.Query(testSameHostNotStatic)
+	assert.NotNil(t, out)
+	if out == nil {
+		t.Fatal("expected non-nil query for the static host")
+	}
+	assert.Equal(t, out.vpnAddrs[0], testSameHostNotStatic)
+	assert.Equal(t, out.vpnAddrs[1], testStaticHost)
+	assert.Equal(t, out.addrs[0], myUdpAddr2)
+}
+
+func TestLighthouse_DeletesWork(t *testing.T) {
+	l := test.NewLogger()
+
+	myUdpAddr2 := netip.MustParseAddrPort("1.2.3.4:4242")
+	testHost := netip.MustParseAddr("10.128.0.42")
+
+	c := config.NewC(l)
+	lh1 := "10.128.0.2"
+	c.Settings["lighthouse"] = map[string]any{
+		"hosts":    []any{lh1},
+		"interval": "1s",
+	}
+
+	c.Settings["listen"] = map[string]any{"port": 4242}
+	c.Settings["static_host_map"] = map[string]any{
+		lh1: []any{"1.1.1.1:4242"},
+	}
+
+	myVpnNet := netip.MustParsePrefix("10.128.0.1/24")
+	nt := new(bart.Lite)
+	nt.Insert(myVpnNet)
+	cs := &CertState{
+		myVpnNetworks:      []netip.Prefix{myVpnNet},
+		myVpnNetworksTable: nt,
+	}
+	lh, err := NewLightHouseFromConfig(t.Context(), l, c, cs, nil, nil)
+	require.NoError(t, err)
+	lh.ifce = &mockEncWriter{}
+
+	//insert the host
+	am := lh.unlockedGetRemoteList([]netip.Addr{testHost})
+	am.vpnAddrs = []netip.Addr{testHost}
+	am.addrs = []netip.AddrPort{myUdpAddr2}
+	lh.addrMap[testHost] = am
+	am.Rebuild([]netip.Prefix{}) //???
+
+	//test that we actually have the entry:
+	out := lh.Query(testHost)
+	assert.NotNil(t, out)
+	assert.Equal(t, out.vpnAddrs[0], testHost)
+	out.Rebuild([]netip.Prefix{}) //why tho
+	assert.Equal(t, out.addrs[0], myUdpAddr2)
+
+	//now do the delete
+	lh.DeleteVpnAddrs([]netip.Addr{testHost})
+	//verify
+	out = lh.Query(testHost)
+	assert.Nil(t, out)
+}

main.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"runtime/debug"
+	"strings"
 	"time"
 
 	"github.com/sirupsen/logrus"
@@ -13,7 +15,7 @@ import (
 	"github.com/slackhq/nebula/sshd"
 	"github.com/slackhq/nebula/udp"
 	"github.com/slackhq/nebula/util"
-	"gopkg.in/yaml.v3"
+	"go.yaml.in/yaml/v3"
 )
 
 type m = map[string]any
@@ -27,6 +29,10 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		}
 	}()
 
+	if buildVersion == "" {
+		buildVersion = moduleVersion()
+	}
+
 	l := logger
 	l.Formatter = &logrus.TextFormatter{
 		FullTimestamp: true,
@@ -75,7 +81,8 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 	if c.GetBool("sshd.enabled", false) {
 		sshStart, err = configSSH(l, ssh, c)
 		if err != nil {
-			return nil, util.ContextualizeIfNeeded("Error while configuring the sshd", err)
+			l.WithError(err).Warn("Failed to configure sshd, ssh debugging will not be available")
+			sshStart = nil
 		}
 	}
 
@@ -98,11 +105,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		// deprecated and undocumented
 		tunQueues := c.GetInt("tun.routines", 1)
 		udpQueues := c.GetInt("listen.routines", 1)
-		if tunQueues > udpQueues {
+		routines = max(tunQueues, udpQueues)
-			routines = tunQueues
-		} else {
-			routines = udpQueues
-		}
 		if routines != 1 {
 			l.WithField("routines", routines).Warn("Setting tun.routines and listen.routines is deprecated. Use `routines` instead")
 		}
@@ -128,7 +131,8 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 			deviceFactory = overlay.NewDeviceFromConfig
 		}
 
-		tun, err = deviceFactory(c, l, pki.getCertState().myVpnNetworks, routines)
+		cs := pki.getCertState()
+		tun, err = deviceFactory(c, l, cs.myVpnNetworks, cs.GetDefaultCertificate().UnsafeNetworks(), routines)
 		if err != nil {
 			return nil, util.ContextualizeIfNeeded("Failed to get a tun/tap device", err)
 		}
@@ -185,6 +189,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 
 	hostMap := NewHostMapFromConfig(l, c)
 	punchy := NewPunchyFromConfig(l, c)
+	connManager := newConnectionManagerFromConfig(l, c, hostMap, punchy)
 	lightHouse, err := NewLightHouseFromConfig(ctx, l, c, pki.getCertState(), udpConns[0], punchy)
 	if err != nil {
 		return nil, util.ContextualizeIfNeeded("Failed to initialize lighthouse handler", err)
@@ -220,31 +225,26 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		}
 	}
 
-	checkInterval := c.GetInt("timers.connection_alive_interval", 5)
-	pendingDeletionInterval := c.GetInt("timers.pending_deletion_interval", 10)
-
 	ifConfig := &InterfaceConfig{
-		HostMap:                 hostMap,
+		HostMap:               hostMap,
-		Inside:                  tun,
+		Inside:                tun,
-		Outside:                 udpConns[0],
+		Outside:               udpConns[0],
-		pki:                     pki,
+		pki:                   pki,
-		Firewall:                fw,
+		Firewall:              fw,
-		ServeDns:                serveDns,
+		ServeDns:              serveDns,
-		HandshakeManager:        handshakeManager,
+		HandshakeManager:      handshakeManager,
-		lightHouse:              lightHouse,
+		connectionManager:     connManager,
-		checkInterval:           time.Second * time.Duration(checkInterval),
+		lightHouse:            lightHouse,
-		pendingDeletionInterval: time.Second * time.Duration(pendingDeletionInterval),
+		tryPromoteEvery:       c.GetUint32("counters.try_promote", defaultPromoteEvery),
-		tryPromoteEvery:         c.GetUint32("counters.try_promote", defaultPromoteEvery),
+		reQueryEvery:          c.GetUint32("counters.requery_every_packets", defaultReQueryEvery),
-		reQueryEvery:            c.GetUint32("counters.requery_every_packets", defaultReQueryEvery),
+		reQueryWait:           c.GetDuration("timers.requery_wait_duration", defaultReQueryWait),
-		reQueryWait:             c.GetDuration("timers.requery_wait_duration", defaultReQueryWait),
+		DropLocalBroadcast:    c.GetBool("tun.drop_local_broadcast", false),
-		DropLocalBroadcast:      c.GetBool("tun.drop_local_broadcast", false),
+		DropMulticast:         c.GetBool("tun.drop_multicast", false),
-		DropMulticast:           c.GetBool("tun.drop_multicast", false),
+		routines:              routines,
-		routines:                routines,
+		MessageMetrics:        messageMetrics,
-		MessageMetrics:          messageMetrics,
+		version:               buildVersion,
-		version:                 buildVersion,
+		relayManager:          NewRelayManager(ctx, l, hostMap, c),
-		relayManager:            NewRelayManager(ctx, l, hostMap, c),
+		punchy:                punchy,
-		punchy:                  punchy,
-
 		ConntrackCacheTimeout: conntrackCacheTimeout,
 		l:                     l,
 	}
@@ -262,6 +262,7 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		ifce.RegisterConfigChangeCallbacks(c)
 		ifce.reloadDisconnectInvalid(c)
 		ifce.reloadSendRecvError(c)
+		ifce.reloadAcceptRecvError(c)
 
 		handshakeManager.f = ifce
 		go handshakeManager.Run(ctx)
@@ -296,5 +297,21 @@ func Main(c *config.C, configTest bool, buildVersion string, logger *logrus.Logg
 		statsStart,
 		dnsStart,
 		lightHouse.StartUpdateWorker,
+		connManager.Start,
 	}, nil
 }
+
+func moduleVersion() string {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return ""
+	}
+
+	for _, dep := range info.Deps {
+		if dep.Path == "github.com/slackhq/nebula" {
+			return strings.TrimPrefix(dep.Version, "v")
+		}
+	}
+
+	return ""
+}

noiseutil/boring.go

@@ -22,7 +22,7 @@ const EncryptLockNeeded = true
 // NewGCMTLS is no longer exposed in go1.19+, so we need to link it in
 // See: https://github.com/golang/go/issues/56326
 //
-// NewGCMTLS is the internal method used with boringcrypto that provices a
+// NewGCMTLS is the internal method used with boringcrypto that provides a
 // validated mode of AES-GCM which enforces the nonce is strictly
 // monotonically increasing.  This is the TLS 1.2 specification for nonce
 // generation (which also matches the method used by the Noise Protocol)

notboring.go

@@ -1,5 +1,4 @@
 //go:build !boringcrypto
-// +build !boringcrypto
 
 package nebula
 

outside.go

@@ -19,21 +19,21 @@ const (
 	minFwPacketLen = 4
 )
 
-func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []byte, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
+func (f *Interface) readOutsidePackets(via ViaSender, out []byte, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
 	err := h.Parse(packet)
 	if err != nil {
 		// Hole punch packets are 0 or 1 byte big, so lets ignore printing those errors
 		if len(packet) > 1 {
-			f.l.WithField("packet", packet).Infof("Error while parsing inbound packet from %s: %s", ip, err)
+			f.l.WithField("packet", packet).Infof("Error while parsing inbound packet from %s: %s", via, err)
 		}
 		return
 	}
 
 	//l.Error("in packet ", header, packet[HeaderLen:])
-	if ip.IsValid() {
+	if !via.IsRelayed {
-		if f.myVpnNetworksTable.Contains(ip.Addr()) {
+		if f.myVpnNetworksTable.Contains(via.UdpAddr.Addr()) {
 			if f.l.Level >= logrus.DebugLevel {
-				f.l.WithField("udpAddr", ip).Debug("Refusing to process double encrypted packet")
+				f.l.WithField("from", via).Debug("Refusing to process double encrypted packet")
 			}
 			return
 		}
@@ -54,8 +54,7 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 
 	switch h.Type {
 	case header.Message:
-		// TODO handleEncrypted sends directly to addr on error. Handle this in the tunneling case.
+		if !f.handleEncrypted(ci, via, h) {
-		if !f.handleEncrypted(ci, ip, h) {
 			return
 		}
 
@@ -79,9 +78,9 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 			// Successfully validated the thing. Get rid of the Relay header.
 			signedPayload = signedPayload[header.Len:]
 			// Pull the Roaming parts up here, and return in all call paths.
-			f.handleHostRoaming(hostinfo, ip)
+			f.handleHostRoaming(hostinfo, via)
 			// Track usage of both the HostInfo and the Relay for the received & authenticated packet
-			f.connectionManager.In(hostinfo.localIndexId)
+			f.connectionManager.In(hostinfo)
 			f.connectionManager.RelayUsed(h.RemoteIndex)
 
 			relay, ok := hostinfo.relayState.QueryRelayForByIdx(h.RemoteIndex)
@@ -96,7 +95,14 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 			case TerminalType:
 				// If I am the target of this relay, process the unwrapped packet
 				// From this recursive point, all these variables are 'burned'. We shouldn't rely on them again.
-				f.readOutsidePackets(netip.AddrPort{}, &ViaSender{relayHI: hostinfo, remoteIdx: relay.RemoteIndex, relay: relay}, out[:0], signedPayload, h, fwPacket, lhf, nb, q, localCache)
+				via = ViaSender{
+					UdpAddr:   via.UdpAddr,
+					relayHI:   hostinfo,
+					remoteIdx: relay.RemoteIndex,
+					relay:     relay,
+					IsRelayed: true,
+				}
+				f.readOutsidePackets(via, out[:0], signedPayload, h, fwPacket, lhf, nb, q, localCache)
 				return
 			case ForwardingType:
 				// Find the target HostInfo relay object
@@ -126,31 +132,32 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 
 	case header.LightHouse:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		if !f.handleEncrypted(ci, ip, h) {
+		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
 
 		d, err := f.decrypt(hostinfo, h.MessageCounter, out, packet, h, nb)
 		if err != nil {
-			hostinfo.logger(f.l).WithError(err).WithField("udpAddr", ip).
+			hostinfo.logger(f.l).WithError(err).WithField("from", via).
 				WithField("packet", packet).
 				Error("Failed to decrypt lighthouse packet")
 			return
 		}
 
-		lhf.HandleRequest(ip, hostinfo.vpnAddrs, d, f)
+		//TODO: assert via is not relayed
+		lhf.HandleRequest(via.UdpAddr, hostinfo.vpnAddrs, d, f)
 
 		// Fallthrough to the bottom to record incoming traffic
 
 	case header.Test:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		if !f.handleEncrypted(ci, ip, h) {
+		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
 
 		d, err := f.decrypt(hostinfo, h.MessageCounter, out, packet, h, nb)
 		if err != nil {
-			hostinfo.logger(f.l).WithError(err).WithField("udpAddr", ip).
+			hostinfo.logger(f.l).WithError(err).WithField("from", via).
 				WithField("packet", packet).
 				Error("Failed to decrypt test packet")
 			return
@@ -159,7 +166,7 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 		if h.Subtype == header.TestRequest {
 			// This testRequest might be from TryPromoteBest, so we should roam
 			// to the new IP address before responding
-			f.handleHostRoaming(hostinfo, ip)
+			f.handleHostRoaming(hostinfo, via)
 			f.send(header.Test, header.TestReply, ci, hostinfo, d, nb, out)
 		}
 
@@ -170,34 +177,34 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 
 	case header.Handshake:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		f.handshakeManager.HandleIncoming(ip, via, packet, h)
+		f.handshakeManager.HandleIncoming(via, packet, h)
 		return
 
 	case header.RecvError:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		f.handleRecvError(ip, h)
+		f.handleRecvError(via.UdpAddr, h)
 		return
 
 	case header.CloseTunnel:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		if !f.handleEncrypted(ci, ip, h) {
+		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
 
-		hostinfo.logger(f.l).WithField("udpAddr", ip).
+		hostinfo.logger(f.l).WithField("from", via).
 			Info("Close tunnel received, tearing down.")
 
 		f.closeTunnel(hostinfo)
 		return
 
 	case header.Control:
-		if !f.handleEncrypted(ci, ip, h) {
+		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
 
 		d, err := f.decrypt(hostinfo, h.MessageCounter, out, packet, h, nb)
 		if err != nil {
-			hostinfo.logger(f.l).WithError(err).WithField("udpAddr", ip).
+			hostinfo.logger(f.l).WithError(err).WithField("from", via).
 				WithField("packet", packet).
 				Error("Failed to decrypt Control packet")
 			return
@@ -207,13 +214,13 @@ func (f *Interface) readOutsidePackets(ip netip.AddrPort, via *ViaSender, out []
 
 	default:
 		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-		hostinfo.logger(f.l).Debugf("Unexpected packet received from %s", ip)
+		hostinfo.logger(f.l).Debugf("Unexpected packet received from %s", via)
 		return
 	}
 
-	f.handleHostRoaming(hostinfo, ip)
+	f.handleHostRoaming(hostinfo, via)
 
-	f.connectionManager.In(hostinfo.localIndexId)
+	f.connectionManager.In(hostinfo)
 }
 
 // closeTunnel closes a tunnel locally, it does not send a closeTunnel packet to the remote
@@ -230,40 +237,42 @@ func (f *Interface) sendCloseTunnel(h *HostInfo) {
 	f.send(header.CloseTunnel, 0, h.ConnectionState, h, []byte{}, make([]byte, 12, 12), make([]byte, mtu))
 }
 
-func (f *Interface) handleHostRoaming(hostinfo *HostInfo, udpAddr netip.AddrPort) {
+func (f *Interface) handleHostRoaming(hostinfo *HostInfo, via ViaSender) {
-	if udpAddr.IsValid() && hostinfo.remote != udpAddr {
+	if !via.IsRelayed && hostinfo.remote != via.UdpAddr {
-		if !f.lightHouse.GetRemoteAllowList().AllowAll(hostinfo.vpnAddrs, udpAddr.Addr()) {
+		if !f.lightHouse.GetRemoteAllowList().AllowAll(hostinfo.vpnAddrs, via.UdpAddr.Addr()) {
-			hostinfo.logger(f.l).WithField("newAddr", udpAddr).Debug("lighthouse.remote_allow_list denied roaming")
+			hostinfo.logger(f.l).WithField("newAddr", via.UdpAddr).Debug("lighthouse.remote_allow_list denied roaming")
 			return
 		}
 
-		if !hostinfo.lastRoam.IsZero() && udpAddr == hostinfo.lastRoamRemote && time.Since(hostinfo.lastRoam) < RoamingSuppressSeconds*time.Second {
+		if !hostinfo.lastRoam.IsZero() && via.UdpAddr == hostinfo.lastRoamRemote && time.Since(hostinfo.lastRoam) < RoamingSuppressSeconds*time.Second {
 			if f.l.Level >= logrus.DebugLevel {
-				hostinfo.logger(f.l).WithField("udpAddr", hostinfo.remote).WithField("newAddr", udpAddr).
+				hostinfo.logger(f.l).WithField("udpAddr", hostinfo.remote).WithField("newAddr", via.UdpAddr).
 					Debugf("Suppressing roam back to previous remote for %d seconds", RoamingSuppressSeconds)
 			}
 			return
 		}
 
-		hostinfo.logger(f.l).WithField("udpAddr", hostinfo.remote).WithField("newAddr", udpAddr).
+		hostinfo.logger(f.l).WithField("udpAddr", hostinfo.remote).WithField("newAddr", via.UdpAddr).
 			Info("Host roamed to new udp ip/port.")
 		hostinfo.lastRoam = time.Now()
 		hostinfo.lastRoamRemote = hostinfo.remote
-		hostinfo.SetRemote(udpAddr)
+		hostinfo.SetRemote(via.UdpAddr)
 	}
 
 }
 
-func (f *Interface) handleEncrypted(ci *ConnectionState, addr netip.AddrPort, h *header.H) bool {
+// handleEncrypted returns true if a packet should be processed, false otherwise
-	// If connectionstate exists and the replay protector allows, process packet
+func (f *Interface) handleEncrypted(ci *ConnectionState, via ViaSender, h *header.H) bool {
-	// Else, send recv errors for 300 seconds after a restart to allow fast reconnection.
+	// If connectionstate does not exist, send a recv error, if possible, to encourage a fast reconnect
-	if ci == nil || !ci.window.Check(f.l, h.MessageCounter) {
+	if ci == nil {
-		if addr.IsValid() {
+		if !via.IsRelayed {
-			f.maybeSendRecvError(addr, h.RemoteIndex)
+			f.maybeSendRecvError(via.UdpAddr, h.RemoteIndex)
-			return false
-		} else {
-			return false
 		}
+		return false
+	}
+	// If the window check fails, refuse to process the packet, but don't send a recv error
+	if !ci.window.Check(f.l, h.MessageCounter) {
+		return false
 	}
 
 	return true
@@ -318,13 +327,29 @@ func parseV6(data []byte, incoming bool, fp *firewall.Packet) error {
 		proto := layers.IPProtocol(data[protoAt])
 
 		switch proto {
-		case layers.IPProtocolICMPv6, layers.IPProtocolESP, layers.IPProtocolNoNextHeader:
+		case layers.IPProtocolESP, layers.IPProtocolNoNextHeader:
 			fp.Protocol = uint8(proto)
 			fp.RemotePort = 0
 			fp.LocalPort = 0
 			fp.Fragment = false
 			return nil
 
+		case layers.IPProtocolICMPv6:
+			if dataLen < offset+6 {
+				return ErrIPv6PacketTooShort
+			}
+			fp.Protocol = uint8(proto)
+			fp.LocalPort = 0 //incoming vs outgoing doesn't matter for icmpv6
+			icmptype := data[offset+1]
+			switch icmptype {
+			case layers.ICMPv6TypeEchoRequest, layers.ICMPv6TypeEchoReply:
+				fp.RemotePort = binary.BigEndian.Uint16(data[offset+4 : offset+6]) //identifier
+			default:
+				fp.RemotePort = 0
+			}
+			fp.Fragment = false
+			return nil
+
 		case layers.IPProtocolTCP, layers.IPProtocolUDP:
 			if dataLen < offset+4 {
 				return ErrIPv6PacketTooShort
@@ -414,34 +439,38 @@ func parseV4(data []byte, incoming bool, fp *firewall.Packet) error {
 
 	// Accounting for a variable header length, do we have enough data for our src/dst tuples?
 	minLen := ihl
-	if !fp.Fragment && fp.Protocol != firewall.ProtoICMP {
+	if !fp.Fragment {
-		minLen += minFwPacketLen
+		if fp.Protocol == firewall.ProtoICMP {
+			minLen += minFwPacketLen + 2
+		} else {
+			minLen += minFwPacketLen
+		}
 	}
+
 	if len(data) < minLen {
 		return ErrIPv4InvalidHeaderLength
 	}
 
-	// Firewall packets are locally oriented
+	if incoming { // Firewall packets are locally oriented
-	if incoming {
 		fp.RemoteAddr, _ = netip.AddrFromSlice(data[12:16])
 		fp.LocalAddr, _ = netip.AddrFromSlice(data[16:20])
-		if fp.Fragment || fp.Protocol == firewall.ProtoICMP {
-			fp.RemotePort = 0
-			fp.LocalPort = 0
-		} else {
-			fp.RemotePort = binary.BigEndian.Uint16(data[ihl : ihl+2])
-			fp.LocalPort = binary.BigEndian.Uint16(data[ihl+2 : ihl+4])
-		}
 	} else {
 		fp.LocalAddr, _ = netip.AddrFromSlice(data[12:16])
 		fp.RemoteAddr, _ = netip.AddrFromSlice(data[16:20])
-		if fp.Fragment || fp.Protocol == firewall.ProtoICMP {
+	}
-			fp.RemotePort = 0
+
-			fp.LocalPort = 0
+	if fp.Fragment {
-		} else {
+		fp.RemotePort = 0
-			fp.LocalPort = binary.BigEndian.Uint16(data[ihl : ihl+2])
+		fp.LocalPort = 0
-			fp.RemotePort = binary.BigEndian.Uint16(data[ihl+2 : ihl+4])
+	} else if fp.Protocol == firewall.ProtoICMP { //note that orientation doesn't matter on ICMP
-		}
+		fp.RemotePort = binary.BigEndian.Uint16(data[ihl+4 : ihl+6]) //identifier
+		fp.LocalPort = 0                                             //code would be uint16(data[ihl+1])
+	} else if incoming {
+		fp.RemotePort = binary.BigEndian.Uint16(data[ihl : ihl+2])  //src port
+		fp.LocalPort = binary.BigEndian.Uint16(data[ihl+2 : ihl+4]) //dst port
+	} else {
+		fp.LocalPort = binary.BigEndian.Uint16(data[ihl : ihl+2])    //src port
+		fp.RemotePort = binary.BigEndian.Uint16(data[ihl+2 : ihl+4]) //dst port
 	}
 
 	return nil
@@ -485,7 +514,7 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 		return false
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, true, hostinfo, f.pki.GetCAPool(), localCache)
+	dropReason := f.firewall.Drop(*fwPacket, out, true, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason != nil {
 		// NOTE: We give `packet` as the `out` here since we already decrypted from it and we don't need it anymore
 		// This gives us a buffer to build the reject packet in
@@ -498,7 +527,7 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 		return false
 	}
 
-	f.connectionManager.In(hostinfo.localIndexId)
+	f.connectionManager.In(hostinfo)
 	_, err = f.readers[q].Write(out)
 	if err != nil {
 		f.l.WithError(err).Error("Failed to write to tun")
@@ -507,7 +536,7 @@ func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, out
 }
 
 func (f *Interface) maybeSendRecvError(endpoint netip.AddrPort, index uint32) {
-	if f.sendRecvErrorConfig.ShouldSendRecvError(endpoint) {
+	if f.sendRecvErrorConfig.ShouldRecvError(endpoint) {
 		f.sendRecvError(endpoint, index)
 	}
 }
@@ -525,6 +554,13 @@ func (f *Interface) sendRecvError(endpoint netip.AddrPort, index uint32) {
 }
 
 func (f *Interface) handleRecvError(addr netip.AddrPort, h *header.H) {
+	if !f.acceptRecvErrorConfig.ShouldRecvError(addr) {
+		f.l.WithField("index", h.RemoteIndex).
+			WithField("udpAddr", addr).
+			Debug("Recv error received, ignoring")
+		return
+	}
+
 	if f.l.Level >= logrus.DebugLevel {
 		f.l.WithField("index", h.RemoteIndex).
 			WithField("udpAddr", addr).
@@ -537,10 +573,6 @@ func (f *Interface) handleRecvError(addr netip.AddrPort, h *header.H) {
 		return
 	}
 
-	if !hostinfo.RecvErrorExceeded() {
-		return
-	}
-
 	if hostinfo.remote.IsValid() && hostinfo.remote != addr {
 		f.l.Infoln("Someone spoofing recv_errors? ", addr, hostinfo.remote)
 		return

outside_test.go

@@ -155,6 +155,7 @@ func Test_newPacket_v6(t *testing.T) {
 	// next layer, missing length byte
 	err = newPacket(buffer.Bytes()[:49], true, p)
 	require.ErrorIs(t, err, ErrIPv6CouldNotFindPayload)
+	err = nil
 
 	// A good ICMP packet
 	ip = layers.IPv6{
@@ -165,20 +166,26 @@ func Test_newPacket_v6(t *testing.T) {
 		DstIP:      net.IPv6linklocalallnodes,
 	}
 
-	icmp := layers.ICMPv6{}
+	icmp := layers.ICMPv6{
-
+		TypeCode: layers.ICMPv6TypeEchoRequest,
-	buffer.Clear()
+		Checksum: 0x1234,
-	err = gopacket.SerializeLayers(buffer, opt, &ip, &icmp)
-	if err != nil {
-		panic(err)
 	}
 
-	err = newPacket(buffer.Bytes(), true, p)
+	buffer.Clear()
-	require.NoError(t, err)
+	require.NoError(t, gopacket.SerializeLayers(buffer, opt, &ip, &icmp))
+	require.Error(t, newPacket(buffer.Bytes(), true, p))
+
+	buffer.Clear()
+	echo := layers.ICMPv6Echo{
+		Identifier: 0xabcd,
+		SeqNumber:  1234,
+	}
+	require.NoError(t, gopacket.SerializeLayers(buffer, opt, &ip, &icmp, &echo))
+	require.NoError(t, newPacket(buffer.Bytes(), true, p))
 	assert.Equal(t, uint8(layers.IPProtocolICMPv6), p.Protocol)
 	assert.Equal(t, netip.MustParseAddr("ff02::2"), p.RemoteAddr)
 	assert.Equal(t, netip.MustParseAddr("ff02::1"), p.LocalAddr)
-	assert.Equal(t, uint16(0), p.RemotePort)
+	assert.Equal(t, uint16(0xabcd), p.RemotePort)
 	assert.Equal(t, uint16(0), p.LocalPort)
 	assert.False(t, p.Fragment)
 
@@ -574,7 +581,7 @@ func BenchmarkParseV6(b *testing.B) {
 	}
 
 	evilBytes := buffer.Bytes()
-	for i := 0; i < 200; i++ {
+	for range 200 {
 		evilBytes = append(evilBytes, hopHeader...)
 	}
 	evilBytes = append(evilBytes, lastHopHeader...)

overlay/device.go

@@ -11,7 +11,11 @@ type Device interface {
 	io.ReadWriteCloser
 	Activate() error
 	Networks() []netip.Prefix
+	UnsafeNetworks() []netip.Prefix
+	UnsafeIPv4OriginAddress() netip.Prefix
+	SNATAddress() netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
+	SupportsMultiqueue() bool
 	NewMultiQueueReader() (io.ReadWriteCloser, error)
 }

overlay/tun.go

@@ -1,6 +1,10 @@
 package overlay
 
 import (
+	"crypto/rand"
+	"fmt"
+	"io"
+	"net"
 	"net/netip"
 
 	"github.com/sirupsen/logrus"
@@ -10,23 +14,32 @@ import (
 
 const DefaultMTU = 1300
 
-// TODO: We may be able to remove routines
+type NameError struct {
-type DeviceFactory func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error)
+	Name       string
+	Underlying error
+}
 
-func NewDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
+func (e *NameError) Error() string {
+	return fmt.Sprintf("could not set tun device name: %s because %s", e.Name, e.Underlying)
+}
+
+// TODO: We may be able to remove routines
+type DeviceFactory func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error)
+
+func NewDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
 	switch {
 	case c.GetBool("tun.disabled", false):
 		tun := newDisabledTun(vpnNetworks, c.GetInt("tun.tx_queue", 500), c.GetBool("stats.message_metrics", false), l)
 		return tun, nil
 
 	default:
-		return newTun(c, l, vpnNetworks, routines > 1)
+		return newTun(c, l, vpnNetworks, unsafeNetworks, routines > 1)
 	}
 }
 
 func NewFdDeviceFromConfig(fd *int) DeviceFactory {
-	return func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
+	return func(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
-		return newTunFromFd(c, l, *fd, vpnNetworks)
+		return newTunFromFd(c, l, *fd, vpnNetworks, unsafeNetworks)
 	}
 }
 
@@ -70,3 +83,133 @@ func findRemovedRoutes(newRoutes, oldRoutes []Route) []Route {
 
 	return removed
 }
+
+func prefixToMask(prefix netip.Prefix) netip.Addr {
+	pLen := 128
+	if prefix.Addr().Is4() {
+		pLen = 32
+	}
+
+	addr, _ := netip.AddrFromSlice(net.CIDRMask(prefix.Bits(), pLen))
+	return addr
+}
+
+func flipBytes(b []byte) []byte {
+	for i := 0; i < len(b); i++ {
+		b[i] ^= 0xFF
+	}
+	return b
+}
+func orBytes(a []byte, b []byte) []byte {
+	ret := make([]byte, len(a))
+	for i := 0; i < len(a); i++ {
+		ret[i] = a[i] | b[i]
+	}
+	return ret
+}
+
+func getBroadcast(cidr netip.Prefix) netip.Addr {
+	broadcast, _ := netip.AddrFromSlice(
+		orBytes(
+			cidr.Addr().AsSlice(),
+			flipBytes(prefixToMask(cidr).AsSlice()),
+		),
+	)
+	return broadcast
+}
+
+func selectGateway(dest netip.Prefix, gateways []netip.Prefix) (netip.Prefix, error) {
+	for _, gateway := range gateways {
+		if dest.Addr().Is4() && gateway.Addr().Is4() {
+			return gateway, nil
+		}
+
+		if dest.Addr().Is6() && gateway.Addr().Is6() {
+			return gateway, nil
+		}
+	}
+
+	return netip.Prefix{}, fmt.Errorf("no gateway found for %v in the list of vpn networks", dest)
+}
+
+// genLinkLocal generates a random IPv4 link-local address.
+// If randomizer is nil, it uses rand.Reader to find two random bytes
+func genLinkLocal(randomizer io.Reader) netip.Prefix {
+	if randomizer == nil {
+		randomizer = rand.Reader
+	}
+	octets := []byte{169, 254, 0, 0}
+	_, _ = randomizer.Read(octets[2:4])
+	return coerceLinkLocal(octets)
+}
+
+func coerceLinkLocal(octets []byte) netip.Prefix {
+	if octets[3] == 0 {
+		octets[3] = 1 //please no .0 addresses
+	} else if octets[2] == 255 && octets[3] == 255 {
+		octets[3] = 254 //please no broadcast addresses
+	}
+	out, _ := netip.AddrFromSlice(octets)
+	return netip.PrefixFrom(out, 32)
+}
+
+// prepareUnsafeOriginAddr provides the IPv4 address used on IPv6-only clients that need to access IPv4 unsafe routes
+func prepareUnsafeOriginAddr(d Device, l *logrus.Logger, c *config.C, routes []Route) netip.Prefix {
+	if !d.Networks()[0].Addr().Is6() {
+		return netip.Prefix{} //if we have an IPv4 assignment within the overlay, we don't need an unsafe origin address
+	}
+
+	needed := false
+	for _, route := range routes { //or if we have a route defined into an IPv4 range
+		if route.Cidr.Addr().Is4() {
+			needed = true //todo should this only apply to unsafe routes? almost certainly
+			break
+		}
+	}
+	if !needed {
+		return netip.Prefix{}
+	}
+
+	//todo better config name for sure
+	if a := c.GetString("tun.unsafe_origin_address_for_4over6", ""); a != "" {
+		out, err := netip.ParseAddr(a)
+		if err != nil {
+			l.WithField("value", a).WithError(err).Warn("failed to parse tun.unsafe_origin_address_for_4over6, will use a random value")
+		} else if !out.Is4() || !out.IsLinkLocalUnicast() {
+			l.WithField("value", out).Warn("tun.unsafe_origin_address_for_4over6 must be an IPv4 address")
+		} else if out.IsValid() {
+			return netip.PrefixFrom(out, 32)
+		}
+	}
+	return genLinkLocal(nil)
+}
+
+// prepareSnatAddr provides the address that an IPv6-only unsafe router should use to SNAT traffic before handing it to the operating system
+func prepareSnatAddr(d Device, l *logrus.Logger, c *config.C) netip.Prefix {
+	if !d.Networks()[0].Addr().Is6() {
+		return netip.Prefix{} //if we have an IPv4 assignment within the overlay, we don't need a snat address
+	}
+
+	needed := false
+	for _, un := range d.UnsafeNetworks() { //if we are an unsafe router for an IPv4 range
+		if un.Addr().Is4() {
+			needed = true
+			break
+		}
+	}
+	if !needed {
+		return netip.Prefix{}
+	}
+
+	if a := c.GetString("tun.snat_address_for_4over6", ""); a != "" {
+		out, err := netip.ParseAddr(a)
+		if err != nil {
+			l.WithField("value", a).WithError(err).Warn("failed to parse tun.snat_address_for_4over6, will use a random value")
+		} else if !out.Is4() || !out.IsLinkLocalUnicast() {
+			l.WithField("value", out).Warn("tun.snat_address_for_4over6 must be an IPv4 address")
+		} else if out.IsValid() {
+			return netip.PrefixFrom(out, 32)
+		}
+	}
+	return genLinkLocal(nil)
+}

overlay/tun_android.go

@@ -19,14 +19,16 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	fd          int
+	fd               int
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeNetworks   []netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	unsafeIPv4Origin netip.Prefix
-	l           *logrus.Logger
+	Routes           atomic.Pointer[[]Route]
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	l                *logrus.Logger
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
 	// XXX Android returns an fd in non-blocking mode which is necessary for shutdown to work properly.
 	// Be sure not to call file.Fd() as it will set the fd to blocking mode.
 	file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
@@ -35,6 +37,7 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 		ReadWriteCloser: file,
 		fd:              deviceFd,
 		vpnNetworks:     vpnNetworks,
+		unsafeNetworks:  unsafeNetworks,
 		l:               l,
 	}
 
@@ -53,7 +56,7 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 	return t, nil
 }
 
-func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
+func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ []netip.Prefix, _ bool) (*tun, error) {
 	return nil, fmt.Errorf("newTun not supported in Android")
 }
 
@@ -76,6 +79,8 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -91,10 +96,26 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *tun) Name() string {
 	return "android"
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for android")
 }

overlay/tun_darwin.go

@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"net"
 	"net/netip"
 	"os"
 	"sync/atomic"
@@ -25,13 +24,15 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	Device      string
+	Device           string
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	DefaultMTU  int
+	unsafeNetworks   []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeIPv4Origin netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	DefaultMTU       int
-	linkAddr    *netroute.LinkAddr
+	Routes           atomic.Pointer[[]Route]
-	l           *logrus.Logger
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	linkAddr         *netroute.LinkAddr
+	l                *logrus.Logger
 
 	// cache out buffer since we need to prepend 4 bytes for tun metadata
 	out []byte
@@ -80,7 +81,7 @@ type ifreqAlias6 struct {
 	Lifetime   addrLifetime
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
 	name := c.GetString("tun.dev", "")
 	ifIndex := -1
 	if name != "" && name != "utun" {
@@ -128,6 +129,7 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
 		Device:          name,
 		vpnNetworks:     vpnNetworks,
+		unsafeNetworks:  unsafeNetworks,
 		DefaultMTU:      c.GetInt("tun.mtu", DefaultMTU),
 		l:               l,
 	}
@@ -154,7 +156,7 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	return
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Darwin")
 }
 
@@ -214,6 +216,11 @@ func (t *tun) Activate() error {
 			}
 		}
 	}
+	if t.unsafeIPv4Origin.IsValid() && t.unsafeIPv4Origin.Addr().Is4() {
+		if err = t.activate4(t.unsafeIPv4Origin); err != nil {
+			return err
+		}
+	}
 
 	// Run the interface
 	ifrf.Flags = ifrf.Flags | unix.IFF_UP | unix.IFF_RUNNING
@@ -295,7 +302,6 @@ func (t *tun) activate6(network netip.Prefix) error {
 			Vltime: 0xffffffff,
 			Pltime: 0xffffffff,
 		},
-		//TODO: CERT-V2 should we disable DAD (duplicate address detection) and mark this as a secured address?
 		Flags: _IN6_IFF_NODAD,
 	}
 
@@ -316,6 +322,10 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+	}
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -547,20 +557,26 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for darwin")
 }
-
-func prefixToMask(prefix netip.Prefix) netip.Addr {
-	pLen := 128
-	if prefix.Addr().Is4() {
-		pLen = 32
-	}
-
-	addr, _ := netip.AddrFromSlice(net.CIDRMask(prefix.Bits(), pLen))
-	return addr
-}

overlay/tun_disabled.go

@@ -52,6 +52,17 @@ func (t *disabledTun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (*disabledTun) UnsafeNetworks() []netip.Prefix {
+	return nil
+}
+func (*disabledTun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
+func (*disabledTun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (*disabledTun) Name() string {
 	return "disabled"
 }
@@ -105,6 +116,10 @@ func (t *disabledTun) Write(b []byte) (int, error) {
 	return len(b), nil
 }
 
+func (t *disabledTun) SupportsMultiqueue() bool {
+	return true
+}
+
 func (t *disabledTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return t, nil
 }

overlay/tun_freebsd.go

@@ -10,11 +10,9 @@ import (
 	"io"
 	"io/fs"
 	"net/netip"
-	"os"
-	"os/exec"
-	"strconv"
 	"sync/atomic"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"github.com/gaissmai/bart"
@@ -22,12 +20,18 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
 const (
 	// FIODGNAME is defined in sys/sys/filio.h on FreeBSD
 	// For 32-bit systems, use FIODGNAME_32 (not defined in this file: 0x80086678)
-	FIODGNAME = 0x80106678
+	FIODGNAME        = 0x80106678
+	TUNSIFMODE       = 0x8004745e
+	TUNSIFHEAD       = 0x80047460
+	OSIOCAIFADDR_IN6 = 0x8088691b
+	IN6_IFF_NODAD    = 0x0020
 )
 
 type fiodgnameArg struct {
@@ -37,80 +41,203 @@ type fiodgnameArg struct {
 }
 
 type ifreqRename struct {
-	Name [16]byte
+	Name [unix.IFNAMSIZ]byte
 	Data uintptr
 }
 
 type ifreqDestroy struct {
-	Name [16]byte
+	Name [unix.IFNAMSIZ]byte
 	pad  [16]byte
 }
 
-type tun struct {
+type ifReq struct {
-	Device      string
+	Name  [unix.IFNAMSIZ]byte
-	vpnNetworks []netip.Prefix
+	Flags uint16
-	MTU         int
+}
-	Routes      atomic.Pointer[[]Route]
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
-	l           *logrus.Logger
 
-	io.ReadWriteCloser
+type ifreqMTU struct {
+	Name [unix.IFNAMSIZ]byte
+	MTU  int32
+}
+
+type addrLifetime struct {
+	Expire    uint64
+	Preferred uint64
+	Vltime    uint32
+	Pltime    uint32
+}
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+	VHid     uint32
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   addrLifetime
+	VHid       uint32
+}
+
+type tun struct {
+	Device           string
+	vpnNetworks      []netip.Prefix
+	unsafeNetworks   []netip.Prefix
+	unsafeIPv4Origin netip.Prefix
+	MTU              int
+	Routes           atomic.Pointer[[]Route]
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	linkAddr         *netroute.LinkAddr
+	l                *logrus.Logger
+	devFd            int
+}
+
+func (t *tun) Read(to []byte) (int, error) {
+	// use readv() to read from the tunnel device, to eliminate the need for copying the buffer
+	if t.devFd < 0 {
+		return -1, syscall.EINVAL
+	}
+
+	// first 4 bytes is protocol family, in network byte order
+	head := make([]byte, 4)
+
+	iovecs := []syscall.Iovec{
+		{&head[0], 4},
+		{&to[0], uint64(len(to))},
+	}
+
+	n, _, errno := syscall.Syscall(syscall.SYS_READV, uintptr(t.devFd), uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+
+	var err error
+	if errno != 0 {
+		err = syscall.Errno(errno)
+	} else {
+		err = nil
+	}
+	// fix bytes read number to exclude header
+	bytesRead := int(n)
+	if bytesRead < 0 {
+		return bytesRead, err
+	} else if bytesRead < 4 {
+		return 0, err
+	} else {
+		return bytesRead - 4, err
+	}
+}
+
+// Write is only valid for single threaded use
+func (t *tun) Write(from []byte) (int, error) {
+	// use writev() to write to the tunnel device, to eliminate the need for copying the buffer
+	if t.devFd < 0 {
+		return -1, syscall.EINVAL
+	}
+
+	if len(from) <= 1 {
+		return 0, syscall.EIO
+	}
+	ipVer := from[0] >> 4
+	var head []byte
+	// first 4 bytes is protocol family, in network byte order
+	if ipVer == 4 {
+		head = []byte{0, 0, 0, syscall.AF_INET}
+	} else if ipVer == 6 {
+		head = []byte{0, 0, 0, syscall.AF_INET6}
+	} else {
+		return 0, fmt.Errorf("unable to determine IP version from packet")
+	}
+	iovecs := []syscall.Iovec{
+		{&head[0], 4},
+		{&from[0], uint64(len(from))},
+	}
+
+	n, _, errno := syscall.Syscall(syscall.SYS_WRITEV, uintptr(t.devFd), uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+
+	var err error
+	if errno != 0 {
+		err = syscall.Errno(errno)
+	} else {
+		err = nil
+	}
+
+	return int(n) - 4, err
 }
 
 func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
+	if t.devFd >= 0 {
-		if err := t.ReadWriteCloser.Close(); err != nil {
+		err := syscall.Close(t.devFd)
-			return err
-		}
-
-		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
 		if err != nil {
-			return err
+			t.l.WithError(err).Error("Error closing device")
 		}
-		defer syscall.Close(s)
+		t.devFd = -1
 
-		ifreq := ifreqDestroy{Name: t.deviceBytes()}
+		c := make(chan struct{})
+		go func() {
+			// destroying the interface can block if a read() is still pending. Do this asynchronously.
+			defer close(c)
+			s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+			if err == nil {
+				defer syscall.Close(s)
+				ifreq := ifreqDestroy{Name: t.deviceBytes()}
+				err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
+			}
+			if err != nil {
+				t.l.WithError(err).Error("Error destroying tunnel")
+			}
+		}()
 
-		// Destroy the interface
+		// wait up to 1 second so we start blocking at the ioctl
-		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
+		select {
-		return err
+		case <-c:
+		case <-time.After(1 * time.Second):
+		}
 	}
 
 	return nil
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in FreeBSD")
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
 	// Try to open existing tun device
-	var file *os.File
+	var fd int
 	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName != "" {
-		file, err = os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+		fd, err = syscall.Open("/dev/"+deviceName, syscall.O_RDWR, 0)
 	}
 	if errors.Is(err, fs.ErrNotExist) || deviceName == "" {
 		// If the device doesn't already exist, request a new one and rename it
-		file, err = os.OpenFile("/dev/tun", os.O_RDWR, 0)
+		fd, err = syscall.Open("/dev/tun", syscall.O_RDWR, 0)
 	}
 	if err != nil {
 		return nil, err
 	}
 
-	rawConn, err := file.SyscallConn()
+	// Read the name of the interface
-	if err != nil {
+	var name [16]byte
-		return nil, fmt.Errorf("SyscallConn: %v", err)
+	arg := fiodgnameArg{length: 16, buf: unsafe.Pointer(&name)}
+	ctrlErr := ioctl(uintptr(fd), FIODGNAME, uintptr(unsafe.Pointer(&arg)))
+
+	if ctrlErr == nil {
+		// set broadcast mode and multicast
+		ifmode := uint32(unix.IFF_BROADCAST | unix.IFF_MULTICAST)
+		ctrlErr = ioctl(uintptr(fd), TUNSIFMODE, uintptr(unsafe.Pointer(&ifmode)))
+	}
+
+	if ctrlErr == nil {
+		// turn on link-layer mode, to support ipv6
+		ifhead := uint32(1)
+		ctrlErr = ioctl(uintptr(fd), TUNSIFHEAD, uintptr(unsafe.Pointer(&ifhead)))
 	}
 
-	var name [16]byte
-	var ctrlErr error
-	rawConn.Control(func(fd uintptr) {
-		// Read the name of the interface
-		arg := fiodgnameArg{length: 16, buf: unsafe.Pointer(&name)}
-		ctrlErr = ioctl(fd, FIODGNAME, uintptr(unsafe.Pointer(&arg)))
-	})
 	if ctrlErr != nil {
 		return nil, err
 	}
@@ -122,11 +249,7 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 
 	// If the name doesn't match the desired interface name, rename it now
 	if ifName != deviceName {
-		s, err := syscall.Socket(
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
-			syscall.AF_INET,
-			syscall.SOCK_DGRAM,
-			syscall.IPPROTO_IP,
-		)
 		if err != nil {
 			return nil, err
 		}
@@ -145,15 +268,16 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		}
 
 		// Set the device name
-		ioctl(fd, syscall.SIOCSIFNAME, uintptr(unsafe.Pointer(&ifrr)))
+		_ = ioctl(fd, syscall.SIOCSIFNAME, uintptr(unsafe.Pointer(&ifrr)))
 	}
 
 	t := &tun{
-		ReadWriteCloser: file,
+		Device:         deviceName,
-		Device:          deviceName,
+		vpnNetworks:    vpnNetworks,
-		vpnNetworks:     vpnNetworks,
+		unsafeNetworks: unsafeNetworks,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		MTU:            c.GetInt("tun.mtu", DefaultMTU),
-		l:               l,
+		l:              l,
+		devFd:          fd,
 	}
 
 	err = t.reload(c, true)
@@ -172,38 +296,111 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 }
 
 func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
+	if cidr.Addr().Is4() {
-	// TODO use syscalls instead of exec.Command
+		ifr := ifreqAlias4{
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
+			Name: t.deviceBytes(),
-	t.l.Debug("command: ", cmd.String())
+			Addr: unix.RawSockaddrInet4{
-	if err = cmd.Run(); err != nil {
+				Len:    unix.SizeofSockaddrInet4,
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
+				Family: unix.AF_INET,
+				Addr:   cidr.Addr().As4(),
+			},
+			DstAddr: unix.RawSockaddrInet4{
+				Len:    unix.SizeofSockaddrInet4,
+				Family: unix.AF_INET,
+				Addr:   getBroadcast(cidr).As4(),
+			},
+			MaskAddr: unix.RawSockaddrInet4{
+				Len:    unix.SizeofSockaddrInet4,
+				Family: unix.AF_INET,
+				Addr:   prefixToMask(cidr).As4(),
+			},
+			VHid: 0,
+		}
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+		// Note: unix.SIOCAIFADDR corresponds to FreeBSD's OSIOCAIFADDR
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&ifr))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/route", "-n", "add", "-net", cidr.String(), "-interface", t.Device)
+	if cidr.Addr().Is6() {
-	t.l.Debug("command: ", cmd.String())
+		ifr := ifreqAlias6{
-	if err = cmd.Run(); err != nil {
+			Name: t.deviceBytes(),
-		return fmt.Errorf("failed to run 'route add': %s", err)
+			Addr: unix.RawSockaddrInet6{
+				Len:    unix.SizeofSockaddrInet6,
+				Family: unix.AF_INET6,
+				Addr:   cidr.Addr().As16(),
+			},
+			PrefixMask: unix.RawSockaddrInet6{
+				Len:    unix.SizeofSockaddrInet6,
+				Family: unix.AF_INET6,
+				Addr:   prefixToMask(cidr).As16(),
+			},
+			Lifetime: addrLifetime{
+				Expire:    0,
+				Preferred: 0,
+				Vltime:    0xffffffff,
+				Pltime:    0xffffffff,
+			},
+			Flags: IN6_IFF_NODAD,
+		}
+		s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), OSIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&ifr))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
+	return fmt.Errorf("unknown address type %v", cidr)
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
 }
 
 func (t *tun) Activate() error {
+	// Setup our default MTU
+	err := t.setMTU()
+	if err != nil {
+		return err
+	}
+
+	linkAddr, err := getLinkAddr(t.Device)
+	if err != nil {
+		return err
+	}
+	if linkAddr == nil {
+		return fmt.Errorf("unable to discover link_addr for tun interface")
+	}
+	t.linkAddr = linkAddr
+
 	for i := range t.vpnNetworks {
 		err := t.addIp(t.vpnNetworks[i])
 		if err != nil {
 			return err
 		}
 	}
-	return nil
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) setMTU() error {
+	// Set the MTU on the device
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ifm := ifreqMTU{Name: t.deviceBytes(), MTU: int32(t.MTU)}
+	err = ioctl(uintptr(s), unix.SIOCSIFMTU, uintptr(unsafe.Pointer(&ifm)))
+	return err
 }
 
 func (t *tun) reload(c *config.C, initial bool) error {
@@ -216,6 +413,10 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+	}
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -252,10 +453,26 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
 }
@@ -268,15 +485,16 @@ func (t *tun) addRoutes(logErrors bool) error {
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "add", "-net", r.Cidr.String(), "-interface", t.Device)
+		err := addRoute(r.Cidr, t.linkAddr)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
 			if logErrors {
 				retErr.Log(t.l)
 			} else {
 				return retErr
 			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
 		}
 	}
 
@@ -289,9 +507,8 @@ func (t *tun) removeRoutes(routes []Route) error {
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-net", r.Cidr.String(), "-interface", t.Device)
+		err := delRoute(r.Cidr, t.linkAddr)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
 			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
 		} else {
 			t.l.WithField("route", r).Info("Removed route")
@@ -306,3 +523,120 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	}
 	return
 }
+
+func addRoute(prefix netip.Prefix, gateway netroute.Addr) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	} else {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			fmt.Println("DOING CHANGE")
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateway netroute.Addr) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	} else {
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: gateway,
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+// getLinkAddr Gets the link address for the interface of the given name
+func getLinkAddr(name string) (*netroute.LinkAddr, error) {
+	rib, err := netroute.FetchRIB(unix.AF_UNSPEC, unix.NET_RT_IFLIST, 0)
+	if err != nil {
+		return nil, err
+	}
+	msgs, err := netroute.ParseRIB(unix.NET_RT_IFLIST, rib)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, m := range msgs {
+		switch m := m.(type) {
+		case *netroute.InterfaceMessage:
+			if m.Name == name {
+				sa, ok := m.Addrs[unix.RTAX_IFP].(*netroute.LinkAddr)
+				if ok {
+					return sa, nil
+				}
+			}
+		}
+	}
+
+	return nil, nil
+}

overlay/tun_ios.go

@@ -22,20 +22,23 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeNetworks   []netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	unsafeIPv4Origin netip.Prefix
-	l           *logrus.Logger
+	Routes           atomic.Pointer[[]Route]
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	l                *logrus.Logger
 }
 
-func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
+func newTun(_ *config.C, _ *logrus.Logger, _ []netip.Prefix, _ []netip.Prefix, _ bool) (*tun, error) {
 	return nil, fmt.Errorf("newTun not supported in iOS")
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/tun")
 	t := &tun{
 		vpnNetworks:     vpnNetworks,
+		unsafeNetworks:  unsafeNetworks,
 		ReadWriteCloser: &tunReadCloser{f: file},
 		l:               l,
 	}
@@ -69,6 +72,8 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -147,10 +152,26 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *tun) Name() string {
 	return "iOS"
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for ios")
 }

overlay/tun_linux.go

@@ -10,6 +10,7 @@ import (
 	"net/netip"
 	"os"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"time"
 	"unsafe"
@@ -25,14 +26,15 @@ import (
 
 type tun struct {
 	io.ReadWriteCloser
-	fd          int
+	fd             int
-	Device      string
+	Device         string
-	vpnNetworks []netip.Prefix
+	vpnNetworks    []netip.Prefix
-	MaxMTU      int
+	unsafeNetworks []netip.Prefix
-	DefaultMTU  int
+	MaxMTU         int
-	TXQueueLen  int
+	DefaultMTU     int
-	deviceIndex int
+	TXQueueLen     int
-	ioctlFd     uintptr
+	deviceIndex    int
+	ioctlFd        uintptr
 
 	Routes                    atomic.Pointer[[]Route]
 	routeTree                 atomic.Pointer[bart.Table[routing.Gateways]]
@@ -40,6 +42,14 @@ type tun struct {
 	useSystemRoutes           bool
 	useSystemRoutesBufferSize int
 
+	// These are routes learned from `tun.use_system_route_table`
+	// stored here to make it easier to restore them after a reload
+	routesFromSystem     map[netip.Prefix]routing.Gateways
+	routesFromSystemLock sync.Mutex
+
+	snatAddr         netip.Prefix
+	unsafeIPv4Origin netip.Prefix
+
 	l *logrus.Logger
 }
 
@@ -47,6 +57,18 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return t.snatAddr
+}
+
 type ifReq struct {
 	Name  [16]byte
 	Flags uint16
@@ -65,10 +87,10 @@ type ifreqQLEN struct {
 	pad   [8]byte
 }
 
-func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
+func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/net/tun")
 
-	t, err := newTunGeneric(c, l, file, vpnNetworks)
+	t, err := newTunGeneric(c, l, file, vpnNetworks, unsafeNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -78,7 +100,7 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, vpnNetworks []net
 	return t, nil
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
 		// If /dev/net/tun doesn't exist, try to create it (will happen in docker)
@@ -106,14 +128,18 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	if multiqueue {
 		req.Flags |= unix.IFF_MULTI_QUEUE
 	}
-	copy(req.Name[:], c.GetString("tun.dev", ""))
+	nameStr := c.GetString("tun.dev", "")
+	copy(req.Name[:], nameStr)
 	if err = ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
-		return nil, err
+		return nil, &NameError{
+			Name:       nameStr,
+			Underlying: err,
+		}
 	}
 	name := strings.Trim(string(req.Name[:]), "\x00")
 
 	file := os.NewFile(uintptr(fd), "/dev/net/tun")
-	t, err := newTunGeneric(c, l, file, vpnNetworks)
+	t, err := newTunGeneric(c, l, file, vpnNetworks, unsafeNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -123,14 +149,16 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, multiqueu
 	return t, nil
 }
 
-func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix) (*tun, error) {
+func newTunGeneric(c *config.C, l *logrus.Logger, file *os.File, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix) (*tun, error) {
 	t := &tun{
 		ReadWriteCloser:           file,
 		fd:                        int(file.Fd()),
 		vpnNetworks:               vpnNetworks,
+		unsafeNetworks:            unsafeNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
 		useSystemRoutes:           c.GetBool("tun.use_system_route_table", false),
 		useSystemRoutesBufferSize: c.GetInt("tun.use_system_route_table_buffer_size", 0),
+		routesFromSystem:          map[netip.Prefix]routing.Gateways{},
 		l:                         l,
 	}
 
@@ -159,11 +187,23 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes) //todo MUST be different from t.snatAddr!
+		t.snatAddr = prepareSnatAddr(t, t.l, c)
+	}
+
 	routeTree, err := makeRouteTree(t.l, routes, true)
 	if err != nil {
 		return err
 	}
 
+	// Bring along any routes learned from the system route table on reload
+	t.routesFromSystemLock.Lock()
+	for dst, gw := range t.routesFromSystem {
+		routeTree.Insert(dst, gw)
+	}
+	t.routesFromSystemLock.Unlock()
+
 	oldDefaultMTU := t.DefaultMTU
 	oldMaxMTU := t.MaxMTU
 	newDefaultMTU := c.GetInt("tun.mtu", DefaultMTU)
@@ -216,6 +256,10 @@ func (t *tun) reload(c *config.C, initial bool) error {
 	return nil
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return true
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
@@ -291,9 +335,19 @@ func (t *tun) addIPs(link netlink.Link) error {
 		}
 	}
 
+	if t.unsafeIPv4Origin.IsValid() {
+		newAddrs = append(newAddrs, &netlink.Addr{
+			IPNet: &net.IPNet{
+				IP:   t.unsafeIPv4Origin.Addr().AsSlice(),
+				Mask: net.CIDRMask(t.unsafeIPv4Origin.Bits(), t.unsafeIPv4Origin.Addr().BitLen()),
+			},
+			Label: t.unsafeIPv4Origin.Addr().Zone(),
+		})
+		t.l.WithField("address", t.unsafeIPv4Origin).Info("Adding origin address for IPv4 unsafe_routes")
+	}
+
 	//add all new addresses
 	for i := range newAddrs {
-		//TODO: CERT-V2 do we want to stack errors and try as many ops as possible?
 		//AddrReplace still adds new IPs, but if their properties change it will change them as well
 		if err := netlink.AddrReplace(link, newAddrs[i]); err != nil {
 			return err
@@ -361,6 +415,11 @@ func (t *tun) Activate() error {
 		t.l.WithError(err).Error("Failed to set tun tx queue length")
 	}
 
+	const modeNone = 1
+	if err = netlink.LinkSetIP6AddrGenMode(link, modeNone); err != nil {
+		t.l.WithError(err).Warn("Failed to disable link local address generation")
+	}
+
 	if err = t.addIPs(link); err != nil {
 		return err
 	}
@@ -374,7 +433,13 @@ func (t *tun) Activate() error {
 	//set route MTU
 	for i := range t.vpnNetworks {
 		if err = t.setDefaultRoute(t.vpnNetworks[i]); err != nil {
-			return fmt.Errorf("failed to set default route MTU: %w", err)
+			return fmt.Errorf("failed to set default route MTU for %s: %w", t.vpnNetworks[i], err)
+		}
+	}
+
+	if t.unsafeIPv4Origin.IsValid() {
+		if err = t.setDefaultRoute(t.unsafeIPv4Origin); err != nil {
+			return fmt.Errorf("failed to set default route MTU for %s: %w", t.unsafeIPv4Origin, err)
 		}
 	}
 
@@ -401,6 +466,23 @@ func (t *tun) setMTU() {
 	}
 }
 
+func (t *tun) setSnatRoute() error {
+	dr := &net.IPNet{
+		IP:   t.snatAddr.Masked().Addr().AsSlice(),
+		Mask: net.CIDRMask(t.snatAddr.Bits(), t.snatAddr.Addr().BitLen()),
+	}
+
+	nr := netlink.Route{
+		LinkIndex: t.deviceIndex,
+		Dst:       dr,
+		Scope:     unix.RT_SCOPE_LINK,
+		//Protocol: unix.RTPROT_KERNEL,
+		Table: unix.RT_TABLE_MAIN,
+		Type:  unix.RTN_UNICAST,
+	}
+	return netlink.RouteReplace(&nr)
+}
+
 func (t *tun) setDefaultRoute(cidr netip.Prefix) error {
 	dr := &net.IPNet{
 		IP:   cidr.Masked().Addr().AsSlice(),
@@ -477,6 +559,13 @@ func (t *tun) addRoutes(logErrors bool) error {
 		}
 	}
 
+	if t.snatAddr.IsValid() {
+		//at least for Linux, we need to set a return route for the SNATted traffic in order to satisfy the reverse-path filter,
+		//and to help the kernel deliver our reply traffic to the tun device.
+		//however, it is important that we do not actually /assign/ the SNAT address,
+		//since link-local addresses will not be routed between interfaces without significant trickery.
+		return t.setSnatRoute()
+	}
 	return nil
 }
 
@@ -578,48 +667,42 @@ func (t *tun) isGatewayInVpnNetworks(gwAddr netip.Addr) bool {
 }
 
 func (t *tun) getGatewaysFromRoute(r *netlink.Route) routing.Gateways {
-
 	var gateways routing.Gateways
 
 	link, err := netlink.LinkByName(t.Device)
 	if err != nil {
-		t.l.WithField("Devicename", t.Device).Error("Ignoring route update: failed to get link by name")
+		t.l.WithField("deviceName", t.Device).Error("Ignoring route update: failed to get link by name")
 		return gateways
 	}
 
 	// If this route is relevant to our interface and there is a gateway then add it
-	if r.LinkIndex == link.Attrs().Index && len(r.Gw) > 0 {
+	if r.LinkIndex == link.Attrs().Index {
-		gwAddr, ok := netip.AddrFromSlice(r.Gw)
+		gwAddr, ok := getGatewayAddr(r.Gw, r.Via)
-		if !ok {
+		if ok {
-			t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway address")
+			if t.isGatewayInVpnNetworks(gwAddr) {
-		} else {
-			gwAddr = gwAddr.Unmap()
-
-			if !t.isGatewayInVpnNetworks(gwAddr) {
-				// Gateway isn't in our overlay network, ignore
-				t.l.WithField("route", r).Debug("Ignoring route update, not in our network")
-			} else {
 				gateways = append(gateways, routing.NewGateway(gwAddr, 1))
+			} else {
+				// Gateway isn't in our overlay network, ignore
+				t.l.WithField("route", r).Debug("Ignoring route update, gateway is not in our network")
 			}
+		} else {
+			t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway or via address")
 		}
 	}
 
 	for _, p := range r.MultiPath {
 		// If this route is relevant to our interface and there is a gateway then add it
-		if p.LinkIndex == link.Attrs().Index && len(p.Gw) > 0 {
+		if p.LinkIndex == link.Attrs().Index {
-			gwAddr, ok := netip.AddrFromSlice(p.Gw)
+			gwAddr, ok := getGatewayAddr(p.Gw, p.Via)
-			if !ok {
+			if ok {
-				t.l.WithField("route", r).Debug("Ignoring multipath route update, invalid gateway address")
+				if t.isGatewayInVpnNetworks(gwAddr) {
-			} else {
-				gwAddr = gwAddr.Unmap()
-
-				if !t.isGatewayInVpnNetworks(gwAddr) {
-					// Gateway isn't in our overlay network, ignore
-					t.l.WithField("route", r).Debug("Ignoring route update, not in our network")
-				} else {
-					// p.Hops+1 = weight of the route
 					gateways = append(gateways, routing.NewGateway(gwAddr, p.Hops+1))
+				} else {
+					// Gateway isn't in our overlay network, ignore
+					t.l.WithField("route", r).Debug("Ignoring route update, gateway is not in our network")
 				}
+			} else {
+				t.l.WithField("route", r).Debug("Ignoring route update, invalid gateway or via address")
 			}
 		}
 	}
@@ -628,16 +711,38 @@ func (t *tun) getGatewaysFromRoute(r *netlink.Route) routing.Gateways {
 	return gateways
 }
 
+func getGatewayAddr(gw net.IP, via netlink.Destination) (netip.Addr, bool) {
+	// Try to use the old RTA_GATEWAY first
+	gwAddr, ok := netip.AddrFromSlice(gw)
+	if !ok {
+		// Fallback to the new RTA_VIA
+		rVia, ok := via.(*netlink.Via)
+		if ok {
+			gwAddr, ok = netip.AddrFromSlice(rVia.Addr)
+		}
+	}
+
+	if gwAddr.IsValid() {
+		gwAddr = gwAddr.Unmap()
+		return gwAddr, true
+	}
+
+	return netip.Addr{}, false
+}
+
 func (t *tun) updateRoutes(r netlink.RouteUpdate) {
-
 	gateways := t.getGatewaysFromRoute(&r.Route)
-
 	if len(gateways) == 0 {
 		// No gateways relevant to our network, no routing changes required.
 		t.l.WithField("route", r).Debug("Ignoring route update, no gateways")
 		return
 	}
 
+	if r.Dst == nil {
+		t.l.WithField("route", r).Debug("Ignoring route update, no destination address")
+		return
+	}
+
 	dstAddr, ok := netip.AddrFromSlice(r.Dst.IP)
 	if !ok {
 		t.l.WithField("route", r).Debug("Ignoring route update, invalid destination address")
@@ -649,14 +754,18 @@ func (t *tun) updateRoutes(r netlink.RouteUpdate) {
 
 	newTree := t.routeTree.Load().Clone()
 
+	t.routesFromSystemLock.Lock()
 	if r.Type == unix.RTM_NEWROUTE {
 		t.l.WithField("destination", dst).WithField("via", gateways).Info("Adding route")
+		t.routesFromSystem[dst] = gateways
 		newTree.Insert(dst, gateways)
 
 	} else {
 		t.l.WithField("destination", dst).WithField("via", gateways).Info("Removing route")
+		delete(t.routesFromSystem, dst)
 		newTree.Delete(dst)
 	}
+	t.routesFromSystemLock.Unlock()
 	t.routeTree.Store(newTree)
 }
 
@@ -671,6 +780,7 @@ func (t *tun) Close() error {
 
 	if t.ioctlFd > 0 {
 		_ = os.NewFile(t.ioctlFd, "ioctlFd").Close()
+		t.ioctlFd = 0
 	}
 
 	return nil

overlay/tun_netbsd.go

@@ -4,13 +4,12 @@
 package overlay
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/netip"
 	"os"
-	"os/exec"
 	"regexp"
-	"strconv"
 	"sync/atomic"
 	"syscall"
 	"unsafe"
@@ -20,54 +19,65 @@ import (
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
-type ifreqDestroy struct {
+const (
-	Name [16]byte
+	SIOCAIFADDR_IN6 = 0x8080696b
-	pad  [16]byte
+	TUNSIFHEAD      = 0x80047442
+	TUNSIFMODE      = 0x80047458
+)
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   addrLifetime
+}
+
+type ifreq struct {
+	Name [unix.IFNAMSIZ]byte
+	data int
+}
+
+type addrLifetime struct {
+	Expire    uint64
+	Preferred uint64
+	Vltime    uint32
+	Pltime    uint32
 }
 
 type tun struct {
-	Device      string
+	Device           string
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	MTU         int
+	unsafeNetworks   []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeIPv4Origin netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	MTU              int
-	l           *logrus.Logger
+	Routes           atomic.Pointer[[]Route]
-
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
-	io.ReadWriteCloser
+	l                *logrus.Logger
-}
+	f                *os.File
-
+	fd               int
-func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
-		if err := t.ReadWriteCloser.Close(); err != nil {
-			return err
-		}
-
-		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
-		if err != nil {
-			return err
-		}
-		defer syscall.Close(s)
-
-		ifreq := ifreqDestroy{Name: t.deviceBytes()}
-
-		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifreq)))
-
-		return err
-	}
-	return nil
-}
-
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
-	return nil, fmt.Errorf("newTunFromFd not supported in NetBSD")
 }
 
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+	return nil, fmt.Errorf("newTunFromFd not supported in NetBSD")
+}
+
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
 	// Try to open tun device
-	var file *os.File
 	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName == "" {
@@ -77,17 +87,23 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
 
-	file, err = os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+	fd, err := unix.Open("/dev/"+deviceName, os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
 	}
 
+	err = unix.SetNonblock(fd, true)
+	if err != nil {
+		l.WithError(err).Warn("Failed to set the tun device as nonblocking")
+	}
+
 	t := &tun{
-		ReadWriteCloser: file,
+		f:           os.NewFile(uintptr(fd), ""),
-		Device:          deviceName,
+		fd:          fd,
-		vpnNetworks:     vpnNetworks,
+		Device:      deviceName,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		vpnNetworks: vpnNetworks,
-		l:               l,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
 	}
 
 	err = t.reload(c, true)
@@ -105,40 +121,225 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	return t, nil
 }
 
+func (t *tun) Close() error {
+	if t.f != nil {
+		if err := t.f.Close(); err != nil {
+			return fmt.Errorf("error closing tun file: %w", err)
+		}
+
+		// t.f.Close should have handled it for us but let's be extra sure
+		_ = unix.Close(t.fd)
+
+		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		ifr := ifreq{Name: t.deviceBytes()}
+		err = ioctl(uintptr(s), syscall.SIOCIFDESTROY, uintptr(unsafe.Pointer(&ifr)))
+		return err
+	}
+	return nil
+}
+
+func (t *tun) Read(to []byte) (int, error) {
+	rc, err := t.f.SyscallConn()
+	if err != nil {
+		return 0, fmt.Errorf("failed to get syscall conn for tun: %w", err)
+	}
+
+	var errno syscall.Errno
+	var n uintptr
+	err = rc.Read(func(fd uintptr) bool {
+		// first 4 bytes is protocol family, in network byte order
+		head := [4]byte{}
+		iovecs := []syscall.Iovec{
+			{&head[0], 4},
+			{&to[0], uint64(len(to))},
+		}
+
+		n, _, errno = syscall.Syscall(syscall.SYS_READV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+		if errno.Temporary() {
+			// We got an EAGAIN, EINTR, or EWOULDBLOCK, go again
+			return false
+		}
+		return true
+	})
+	if err != nil {
+		if err == syscall.EBADF || err.Error() == "use of closed file" {
+			// Go doesn't export poll.ErrFileClosing but happily reports it to us so here we are
+			// https://github.com/golang/go/blob/master/src/internal/poll/fd_poll_runtime.go#L121
+			return 0, os.ErrClosed
+		}
+		return 0, fmt.Errorf("failed to make read call for tun: %w", err)
+	}
+
+	if errno != 0 {
+		return 0, fmt.Errorf("failed to make inner read call for tun: %w", errno)
+	}
+
+	// fix bytes read number to exclude header
+	bytesRead := int(n)
+	if bytesRead < 0 {
+		return bytesRead, nil
+	} else if bytesRead < 4 {
+		return 0, nil
+	} else {
+		return bytesRead - 4, nil
+	}
+}
+
+// Write is only valid for single threaded use
+func (t *tun) Write(from []byte) (int, error) {
+	if len(from) <= 1 {
+		return 0, syscall.EIO
+	}
+
+	ipVer := from[0] >> 4
+	var head [4]byte
+	// first 4 bytes is protocol family, in network byte order
+	if ipVer == 4 {
+		head[3] = syscall.AF_INET
+	} else if ipVer == 6 {
+		head[3] = syscall.AF_INET6
+	} else {
+		return 0, fmt.Errorf("unable to determine IP version from packet")
+	}
+
+	rc, err := t.f.SyscallConn()
+	if err != nil {
+		return 0, err
+	}
+
+	var errno syscall.Errno
+	var n uintptr
+	err = rc.Write(func(fd uintptr) bool {
+		iovecs := []syscall.Iovec{
+			{&head[0], 4},
+			{&from[0], uint64(len(from))},
+		}
+
+		n, _, errno = syscall.Syscall(syscall.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
+		// According to NetBSD documentation for TUN, writes will only return errors in which
+		// this packet will never be delivered so just go on living life.
+		return true
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	if errno != 0 {
+		return 0, errno
+	}
+
+	return int(n) - 4, err
+}
+
 func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
+	if cidr.Addr().Is4() {
+		var req ifreqAlias4
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.DstAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.MaskAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   prefixToMask(cidr).As4(),
+		}
 
-	// TODO use syscalls instead of exec.Command
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
+		if err != nil {
-	t.l.Debug("command: ", cmd.String())
+			return err
-	if err = cmd.Run(); err != nil {
+		}
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr(), err)
+		}
+
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/route", "-n", "add", "-net", cidr.String(), cidr.Addr().String())
+	if cidr.Addr().Is6() {
-	t.l.Debug("command: ", cmd.String())
+		var req ifreqAlias6
-	if err = cmd.Run(); err != nil {
+		req.Name = t.deviceBytes()
-		return fmt.Errorf("failed to run 'route add': %s", err)
+		req.Addr = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   cidr.Addr().As16(),
+		}
+		req.PrefixMask = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   prefixToMask(cidr).As16(),
+		}
+		req.Lifetime = addrLifetime{
+			Vltime: 0xffffffff,
+			Pltime: 0xffffffff,
+		}
+
+		s, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), SIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+		return nil
 	}
 
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
+	return fmt.Errorf("unknown address type %v", cidr)
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
 }
 
 func (t *tun) Activate() error {
+	mode := int32(unix.IFF_BROADCAST)
+	err := ioctl(uintptr(t.fd), TUNSIFMODE, uintptr(unsafe.Pointer(&mode)))
+	if err != nil {
+		return fmt.Errorf("failed to set tun device mode: %w", err)
+	}
+
+	v := 1
+	err = ioctl(uintptr(t.fd), TUNSIFHEAD, uintptr(unsafe.Pointer(&v)))
+	if err != nil {
+		return fmt.Errorf("failed to set tun device head: %w", err)
+	}
+
+	err = t.doIoctlByName(unix.SIOCSIFMTU, uint32(t.MTU))
+	if err != nil {
+		return fmt.Errorf("failed to set tun mtu: %w", err)
+	}
+
 	for i := range t.vpnNetworks {
-		err := t.addIp(t.vpnNetworks[i])
+		err = t.addIp(t.vpnNetworks[i])
 		if err != nil {
 			return err
 		}
 	}
-	return nil
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) doIoctlByName(ctl uintptr, value uint32) error {
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ir := ifreq{Name: t.deviceBytes(), data: int(value)}
+	err = ioctl(uintptr(s), ctl, uintptr(unsafe.Pointer(&ir)))
+	return err
 }
 
 func (t *tun) reload(c *config.C, initial bool) error {
@@ -151,6 +352,10 @@ func (t *tun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+	}
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -187,31 +392,49 @@ func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *tun) Name() string {
 	return t.Device
 }
 
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for netbsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
 	routes := *t.Routes.Load()
+
 	for _, r := range routes {
 		if len(r.Via) == 0 || !r.Install {
 			// We don't allow route MTUs so only install routes with a via
 			continue
 		}
 
-		cmd := exec.Command("/sbin/route", "-n", "add", "-net", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
+		err := addRoute(r.Cidr, t.vpnNetworks)
-		t.l.Debug("command: ", cmd.String())
+		if err != nil {
-		if err := cmd.Run(); err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
 			if logErrors {
 				retErr.Log(t.l)
 			} else {
 				return retErr
 			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
 		}
 	}
 
@@ -224,10 +447,8 @@ func (t *tun) removeRoutes(routes []Route) error {
 			continue
 		}
 
-		//TODO: CERT-V2 is this right?
+		err := delRoute(r.Cidr, t.vpnNetworks)
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-net", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
+		if err != nil {
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
 			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
 		} else {
 			t.l.WithField("route", r).Info("Removed route")
@@ -242,3 +463,109 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	}
 	return
 }
+
+func addRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP | unix.RTF_GATEWAY,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}

overlay/tun_openbsd.go

@@ -4,72 +4,100 @@
 package overlay
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/netip"
 	"os"
-	"os/exec"
 	"regexp"
-	"strconv"
 	"sync/atomic"
 	"syscall"
+	"unsafe"
 
 	"github.com/gaissmai/bart"
 	"github.com/sirupsen/logrus"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	netroute "golang.org/x/net/route"
+	"golang.org/x/sys/unix"
 )
 
+const (
+	SIOCAIFADDR_IN6 = 0x8080691a
+)
+
+type ifreqAlias4 struct {
+	Name     [unix.IFNAMSIZ]byte
+	Addr     unix.RawSockaddrInet4
+	DstAddr  unix.RawSockaddrInet4
+	MaskAddr unix.RawSockaddrInet4
+}
+
+type ifreqAlias6 struct {
+	Name       [unix.IFNAMSIZ]byte
+	Addr       unix.RawSockaddrInet6
+	DstAddr    unix.RawSockaddrInet6
+	PrefixMask unix.RawSockaddrInet6
+	Flags      uint32
+	Lifetime   [2]uint32
+}
+
+type ifreq struct {
+	Name [unix.IFNAMSIZ]byte
+	data int
+}
+
 type tun struct {
-	Device      string
+	Device           string
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	MTU         int
+	unsafeNetworks   []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeIPv4Origin netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	MTU              int
-	l           *logrus.Logger
+	Routes           atomic.Pointer[[]Route]
-
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
-	io.ReadWriteCloser
+	l                *logrus.Logger
-
+	f                *os.File
+	fd               int
 	// cache out buffer since we need to prepend 4 bytes for tun metadata
 	out []byte
 }
 
-func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
-		return t.ReadWriteCloser.Close()
-	}
-
-	return nil
-}
-
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*tun, error) {
-	return nil, fmt.Errorf("newTunFromFd not supported in OpenBSD")
-}
-
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*tun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*tun, error) {
+	return nil, fmt.Errorf("newTunFromFd not supported in openbsd")
+}
+
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*tun, error) {
+	// Try to open tun device
+	var err error
 	deviceName := c.GetString("tun.dev", "")
 	if deviceName == "" {
-		return nil, fmt.Errorf("a device name in the format of tunN must be specified")
+		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
-
 	if !deviceNameRE.MatchString(deviceName) {
-		return nil, fmt.Errorf("a device name in the format of tunN must be specified")
+		return nil, fmt.Errorf("a device name in the format of /dev/tunN must be specified")
 	}
 
-	file, err := os.OpenFile("/dev/"+deviceName, os.O_RDWR, 0)
+	fd, err := unix.Open("/dev/"+deviceName, os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
 	}
 
+	err = unix.SetNonblock(fd, true)
+	if err != nil {
+		l.WithError(err).Warn("Failed to set the tun device as nonblocking")
+	}
+
 	t := &tun{
-		ReadWriteCloser: file,
+		f:              os.NewFile(uintptr(fd), ""),
-		Device:          deviceName,
+		fd:             fd,
-		vpnNetworks:     vpnNetworks,
+		Device:         deviceName,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		vpnNetworks:    vpnNetworks,
-		l:               l,
+		unsafeNetworks: unsafeNetworks,
+		MTU:            c.GetInt("tun.mtu", DefaultMTU),
+		l:              l,
 	}
 
 	err = t.reload(c, true)
@@ -87,139 +115,22 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	return t, nil
 }
 
-func (t *tun) reload(c *config.C, initial bool) error {
+func (t *tun) Close() error {
-	change, routes, err := getAllRoutesFromConfig(c, t.vpnNetworks, initial)
+	if t.f != nil {
-	if err != nil {
+		if err := t.f.Close(); err != nil {
-		return err
+			return fmt.Errorf("error closing tun file: %w", err)
-	}
-
-	if !initial && !change {
-		return nil
-	}
-
-	routeTree, err := makeRouteTree(t.l, routes, false)
-	if err != nil {
-		return err
-	}
-
-	// Teach nebula how to handle the routes before establishing them in the system table
-	oldRoutes := t.Routes.Swap(&routes)
-	t.routeTree.Store(routeTree)
-
-	if !initial {
-		// Remove first, if the system removes a wanted route hopefully it will be re-added next
-		err := t.removeRoutes(findRemovedRoutes(routes, *oldRoutes))
-		if err != nil {
-			util.LogWithContextIfNeeded("Failed to remove routes", err, t.l)
 		}
 
-		// Ensure any routes we actually want are installed
+		// t.f.Close should have handled it for us but let's be extra sure
-		err = t.addRoutes(true)
+		_ = unix.Close(t.fd)
-		if err != nil {
-			// Catch any stray logs
-			util.LogWithContextIfNeeded("Failed to add routes", err, t.l)
-		}
-	}
-
-	return nil
-}
-
-func (t *tun) addIp(cidr netip.Prefix) error {
-	var err error
-	// TODO use syscalls instead of exec.Command
-	cmd := exec.Command("/sbin/ifconfig", t.Device, cidr.String(), cidr.Addr().String())
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	cmd = exec.Command("/sbin/ifconfig", t.Device, "mtu", strconv.Itoa(t.MTU))
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'ifconfig': %s", err)
-	}
-
-	cmd = exec.Command("/sbin/route", "-n", "add", "-inet", cidr.String(), cidr.Addr().String())
-	t.l.Debug("command: ", cmd.String())
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("failed to run 'route add': %s", err)
-	}
-
-	// Unsafe path routes
-	return t.addRoutes(false)
-}
-
-func (t *tun) Activate() error {
-	for i := range t.vpnNetworks {
-		err := t.addIp(t.vpnNetworks[i])
-		if err != nil {
-			return err
-		}
 	}
 	return nil
 }
 
-func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
-	r, _ := t.routeTree.Load().Lookup(ip)
-	return r
-}
-
-func (t *tun) addRoutes(logErrors bool) error {
-	routes := *t.Routes.Load()
-	for _, r := range routes {
-		if len(r.Via) == 0 || !r.Install {
-			// We don't allow route MTUs so only install routes with a via
-			continue
-		}
-		//TODO: CERT-V2 is this right?
-		cmd := exec.Command("/sbin/route", "-n", "add", "-inet", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
-			retErr := util.NewContextualError("failed to run 'route add' for unsafe_route", map[string]any{"route": r}, err)
-			if logErrors {
-				retErr.Log(t.l)
-			} else {
-				return retErr
-			}
-		}
-	}
-
-	return nil
-}
-
-func (t *tun) removeRoutes(routes []Route) error {
-	for _, r := range routes {
-		if !r.Install {
-			continue
-		}
-		//TODO: CERT-V2 is this right?
-		cmd := exec.Command("/sbin/route", "-n", "delete", "-inet", r.Cidr.String(), t.vpnNetworks[0].Addr().String())
-		t.l.Debug("command: ", cmd.String())
-		if err := cmd.Run(); err != nil {
-			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
-		} else {
-			t.l.WithField("route", r).Info("Removed route")
-		}
-	}
-	return nil
-}
-
-func (t *tun) Networks() []netip.Prefix {
-	return t.vpnNetworks
-}
-
-func (t *tun) Name() string {
-	return t.Device
-}
-
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
-}
-
 func (t *tun) Read(to []byte) (int, error) {
 	buf := make([]byte, len(to)+4)
 
-	n, err := t.ReadWriteCloser.Read(buf)
+	n, err := t.f.Read(buf)
 
 	copy(to, buf[4:])
 	return n - 4, err
@@ -250,6 +161,332 @@ func (t *tun) Write(from []byte) (int, error) {
 
 	copy(buf[4:], from)
 
-	n, err := t.ReadWriteCloser.Write(buf)
+	n, err := t.f.Write(buf)
 	return n - 4, err
 }
+
+func (t *tun) addIp(cidr netip.Prefix) error {
+	if cidr.Addr().Is4() {
+		var req ifreqAlias4
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.DstAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   cidr.Addr().As4(),
+		}
+		req.MaskAddr = unix.RawSockaddrInet4{
+			Len:    unix.SizeofSockaddrInet4,
+			Family: unix.AF_INET,
+			Addr:   prefixToMask(cidr).As4(),
+		}
+
+		s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), unix.SIOCAIFADDR, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr(), err)
+		}
+
+		err = addRoute(cidr, t.vpnNetworks)
+		if err != nil {
+			return fmt.Errorf("failed to set route for vpn network %v: %w", cidr, err)
+		}
+
+		return nil
+	}
+
+	if cidr.Addr().Is6() {
+		var req ifreqAlias6
+		req.Name = t.deviceBytes()
+		req.Addr = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   cidr.Addr().As16(),
+		}
+		req.PrefixMask = unix.RawSockaddrInet6{
+			Len:    unix.SizeofSockaddrInet6,
+			Family: unix.AF_INET6,
+			Addr:   prefixToMask(cidr).As16(),
+		}
+		req.Lifetime[0] = 0xffffffff
+		req.Lifetime[1] = 0xffffffff
+
+		s, err := unix.Socket(unix.AF_INET6, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+		if err != nil {
+			return err
+		}
+		defer syscall.Close(s)
+
+		if err := ioctl(uintptr(s), SIOCAIFADDR_IN6, uintptr(unsafe.Pointer(&req))); err != nil {
+			return fmt.Errorf("failed to set tun address %s: %s", cidr.Addr().String(), err)
+		}
+
+		return nil
+	}
+
+	return fmt.Errorf("unknown address type %v", cidr)
+}
+
+func (t *tun) Activate() error {
+	err := t.doIoctlByName(unix.SIOCSIFMTU, uint32(t.MTU))
+	if err != nil {
+		return fmt.Errorf("failed to set tun mtu: %w", err)
+	}
+
+	for i := range t.vpnNetworks {
+		err = t.addIp(t.vpnNetworks[i])
+		if err != nil {
+			return err
+		}
+	}
+
+	return t.addRoutes(false)
+}
+
+func (t *tun) doIoctlByName(ctl uintptr, value uint32) error {
+	s, err := unix.Socket(unix.AF_INET, unix.SOCK_DGRAM, unix.IPPROTO_IP)
+	if err != nil {
+		return err
+	}
+	defer syscall.Close(s)
+
+	ir := ifreq{Name: t.deviceBytes(), data: int(value)}
+	err = ioctl(uintptr(s), ctl, uintptr(unsafe.Pointer(&ir)))
+	return err
+}
+
+func (t *tun) reload(c *config.C, initial bool) error {
+	change, routes, err := getAllRoutesFromConfig(c, t.vpnNetworks, initial)
+	if err != nil {
+		return err
+	}
+
+	if !initial && !change {
+		return nil
+	}
+
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+	}
+
+	routeTree, err := makeRouteTree(t.l, routes, false)
+	if err != nil {
+		return err
+	}
+
+	// Teach nebula how to handle the routes before establishing them in the system table
+	oldRoutes := t.Routes.Swap(&routes)
+	t.routeTree.Store(routeTree)
+
+	if !initial {
+		// Remove first, if the system removes a wanted route hopefully it will be re-added next
+		err := t.removeRoutes(findRemovedRoutes(routes, *oldRoutes))
+		if err != nil {
+			util.LogWithContextIfNeeded("Failed to remove routes", err, t.l)
+		}
+
+		// Ensure any routes we actually want are installed
+		err = t.addRoutes(true)
+		if err != nil {
+			// Catch any stray logs
+			util.LogWithContextIfNeeded("Failed to add routes", err, t.l)
+		}
+	}
+
+	return nil
+}
+
+func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
+	r, _ := t.routeTree.Load().Lookup(ip)
+	return r
+}
+
+func (t *tun) Networks() []netip.Prefix {
+	return t.vpnNetworks
+}
+
+func (t *tun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *tun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *tun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
+func (t *tun) Name() string {
+	return t.Device
+}
+
+func (t *tun) SupportsMultiqueue() bool {
+	return false
+}
+
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for openbsd")
+}
+
+func (t *tun) addRoutes(logErrors bool) error {
+	routes := *t.Routes.Load()
+
+	for _, r := range routes {
+		if len(r.Via) == 0 || !r.Install {
+			// We don't allow route MTUs so only install routes with a via
+			continue
+		}
+
+		err := addRoute(r.Cidr, t.vpnNetworks)
+		if err != nil {
+			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
+			if logErrors {
+				retErr.Log(t.l)
+			} else {
+				return retErr
+			}
+		} else {
+			t.l.WithField("route", r).Info("Added route")
+		}
+	}
+
+	return nil
+}
+
+func (t *tun) removeRoutes(routes []Route) error {
+	for _, r := range routes {
+		if !r.Install {
+			continue
+		}
+
+		err := delRoute(r.Cidr, t.vpnNetworks)
+		if err != nil {
+			t.l.WithError(err).WithField("route", r).Error("Failed to remove route")
+		} else {
+			t.l.WithField("route", r).Info("Removed route")
+		}
+	}
+	return nil
+}
+
+func (t *tun) deviceBytes() (o [16]byte) {
+	for i, c := range t.Device {
+		o[i] = byte(c)
+	}
+	return
+}
+
+func addRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := &netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_ADD,
+		Flags:   unix.RTF_UP | unix.RTF_GATEWAY,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		if errors.Is(err, unix.EEXIST) {
+			// Try to do a change
+			route.Type = unix.RTM_CHANGE
+			data, err = route.Marshal()
+			if err != nil {
+				return fmt.Errorf("failed to create route.RouteMessage for change: %w", err)
+			}
+			_, err = unix.Write(sock, data[:])
+			return err
+		}
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}
+
+func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
+	sock, err := unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
+	if err != nil {
+		return fmt.Errorf("unable to create AF_ROUTE socket: %v", err)
+	}
+	defer unix.Close(sock)
+
+	route := netroute.RouteMessage{
+		Version: unix.RTM_VERSION,
+		Type:    unix.RTM_DELETE,
+		Seq:     1,
+	}
+
+	if prefix.Addr().Is4() {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet4Addr{IP: prefix.Masked().Addr().As4()},
+			unix.RTAX_NETMASK: &netroute.Inet4Addr{IP: prefixToMask(prefix).As4()},
+			unix.RTAX_GATEWAY: &netroute.Inet4Addr{IP: gw.Addr().As4()},
+		}
+	} else {
+		gw, err := selectGateway(prefix, gateways)
+		if err != nil {
+			return err
+		}
+		route.Addrs = []netroute.Addr{
+			unix.RTAX_DST:     &netroute.Inet6Addr{IP: prefix.Masked().Addr().As16()},
+			unix.RTAX_NETMASK: &netroute.Inet6Addr{IP: prefixToMask(prefix).As16()},
+			unix.RTAX_GATEWAY: &netroute.Inet6Addr{IP: gw.Addr().As16()},
+		}
+	}
+
+	data, err := route.Marshal()
+	if err != nil {
+		return fmt.Errorf("failed to create route.RouteMessage: %w", err)
+	}
+	_, err = unix.Write(sock, data[:])
+	if err != nil {
+		return fmt.Errorf("failed to write route.RouteMessage to socket: %w", err)
+	}
+
+	return nil
+}

overlay/tun_snat_test.go

@@ -0,0 +1,179 @@
+package overlay
+
+import (
+	"io"
+	"net/netip"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/routing"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// mockDevice is a minimal Device implementation for testing prepareUnsafeOriginAddr.
+type mockDevice struct {
+	networks       []netip.Prefix
+	unsafeNetworks []netip.Prefix
+	snatAddr       netip.Prefix
+	unsafeSnatAddr netip.Prefix
+}
+
+func (d *mockDevice) Read([]byte) (int, error)                         { return 0, nil }
+func (d *mockDevice) Write([]byte) (int, error)                        { return 0, nil }
+func (d *mockDevice) Close() error                                     { return nil }
+func (d *mockDevice) Activate() error                                  { return nil }
+func (d *mockDevice) Networks() []netip.Prefix                         { return d.networks }
+func (d *mockDevice) UnsafeNetworks() []netip.Prefix                   { return d.unsafeNetworks }
+func (d *mockDevice) SNATAddress() netip.Prefix                        { return d.snatAddr }
+func (d *mockDevice) UnsafeIPv4OriginAddress() netip.Prefix            { return d.unsafeSnatAddr }
+func (d *mockDevice) Name() string                                     { return "mock" }
+func (d *mockDevice) RoutesFor(netip.Addr) routing.Gateways            { return routing.Gateways{} }
+func (d *mockDevice) SupportsMultiqueue() bool                         { return false }
+func (d *mockDevice) NewMultiQueueReader() (io.ReadWriteCloser, error) { return nil, nil }
+
+func TestPrepareSnatAddr_V4Primary_NoSnat(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	// If the device has an IPv4 primary address, no SNAT needed
+	d := &mockDevice{
+		networks: []netip.Prefix{netip.MustParsePrefix("10.0.0.1/24")},
+	}
+	result := prepareUnsafeOriginAddr(d, l, c, nil)
+	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr when device has IPv4 primary")
+}
+
+func TestPrepareSnatAddr_V6Primary_NoUnsafeOrRoutes(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	// IPv6 primary but no unsafe networks or IPv4 routes
+	d := &mockDevice{
+		networks: []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+	}
+	result := prepareUnsafeOriginAddr(d, l, c, nil)
+	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr without IPv4 unsafe networks or routes")
+}
+
+func TestPrepareSnatAddr_V6Primary_WithV4Unsafe(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	// IPv6 primary with IPv4 unsafe network -> should get SNAT addr
+	d := &mockDevice{
+		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
+	}
+	result := prepareSnatAddr(d, l, c)
+	require.True(t, result.IsValid(), "should assign SNAT addr")
+	assert.True(t, result.Addr().Is4(), "SNAT addr should be IPv4")
+	assert.True(t, result.Addr().IsLinkLocalUnicast(), "SNAT addr should be link-local")
+	assert.Equal(t, 32, result.Bits(), "SNAT addr should be /32")
+
+	result = prepareUnsafeOriginAddr(d, l, c, nil)
+	require.False(t, result.IsValid(), "no routes = no origin addr needed")
+}
+
+func TestPrepareUnsafeOriginAddr_V6Primary_WithV4Route(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	// IPv6 primary with IPv4 route -> should get SNAT addr
+	d := &mockDevice{
+		networks: []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+	}
+	routes := []Route{
+		{Cidr: netip.MustParsePrefix("10.0.0.0/8")},
+	}
+	result := prepareUnsafeOriginAddr(d, l, c, routes)
+	require.True(t, result.IsValid(), "should assign SNAT addr when IPv4 route exists")
+	assert.True(t, result.Addr().Is4())
+	assert.True(t, result.Addr().IsLinkLocalUnicast())
+
+	result = prepareSnatAddr(d, l, c)
+	require.False(t, result.IsValid(), "no UnsafeNetworks = no snat addr needed")
+}
+
+func TestPrepareSnatAddr_V6Primary_V6UnsafeOnly(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	// IPv6 primary with only IPv6 unsafe network -> no SNAT needed
+	d := &mockDevice{
+		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("fd01::/64")},
+	}
+	result := prepareUnsafeOriginAddr(d, l, c, nil)
+	assert.Equal(t, netip.Prefix{}, result, "should not assign SNAT addr for IPv6-only unsafe networks")
+}
+
+func TestPrepareSnatAddr_ManualAddress(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+	c.Settings["tun"] = map[string]any{
+		"snat_address_for_4over6": "169.254.42.42",
+	}
+
+	d := &mockDevice{
+		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
+	}
+	result := prepareSnatAddr(d, l, c)
+	require.True(t, result.IsValid())
+	assert.Equal(t, netip.MustParseAddr("169.254.42.42"), result.Addr())
+	assert.Equal(t, 32, result.Bits())
+}
+
+func TestPrepareSnatAddr_InvalidManualAddress_Fallback(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+	c.Settings["tun"] = map[string]any{
+		"snat_address_for_4over6": "not-an-ip",
+	}
+
+	d := &mockDevice{
+		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
+	}
+	result := prepareSnatAddr(d, l, c)
+	// Should fall back to auto-assignment
+	require.True(t, result.IsValid(), "should fall back to auto-assigned address")
+	assert.True(t, result.Addr().Is4())
+	assert.True(t, result.Addr().IsLinkLocalUnicast())
+}
+
+func TestPrepareSnatAddr_AutoGenerated_Range(t *testing.T) {
+	l := logrus.New()
+	l.SetLevel(logrus.PanicLevel)
+	c := config.NewC(l)
+
+	d := &mockDevice{
+		networks:       []netip.Prefix{netip.MustParsePrefix("fd00::1/128")},
+		unsafeNetworks: []netip.Prefix{netip.MustParsePrefix("192.168.0.0/16")},
+	}
+
+	// Generate several addresses and verify they're all in the expected range
+	for i := 0; i < 100; i++ {
+		result := prepareSnatAddr(d, l, c)
+		require.True(t, result.IsValid())
+		addr := result.Addr()
+		octets := addr.As4()
+		assert.Equal(t, byte(169), octets[0], "first octet should be 169")
+		assert.Equal(t, byte(254), octets[1], "second octet should be 254")
+		// Should not have .0 in the last octet
+		assert.NotEqual(t, byte(0), octets[3], "last octet should not be 0")
+		// Should not be 169.254.255.255 (broadcast)
+		if octets[2] == 255 {
+			assert.NotEqual(t, byte(255), octets[3], "should not be broadcast address")
+		}
+	}
+}

overlay/tun_test.go

@@ -0,0 +1,37 @@
+package overlay
+
+import (
+	"bytes"
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLinkLocal(t *testing.T) {
+	r := bytes.NewReader([]byte{42, 99})
+	result := genLinkLocal(r)
+	assert.Equal(t, netip.MustParsePrefix("169.254.42.99/32"), result, "genLinkLocal with a deterministic randomizer")
+
+	result = genLinkLocal(nil)
+	assert.True(t, result.IsValid(), "genLinkLocal with nil randomizer should be valid")
+	assert.True(t, result.Addr().IsLinkLocalUnicast(), "genLinkLocal with nil randomizer should be link-local")
+
+	result = coerceLinkLocal([]byte{169, 254, 100, 50})
+	assert.Equal(t, netip.MustParsePrefix("169.254.100.50/32"), result, "coerceLinkLocal should pass through normal values")
+
+	result = coerceLinkLocal([]byte{169, 254, 0, 0})
+	assert.Equal(t, netip.MustParsePrefix("169.254.0.1/32"), result, "coerceLinkLocal should bump .0 last octet to .1")
+
+	result = coerceLinkLocal([]byte{169, 254, 255, 255})
+	assert.Equal(t, netip.MustParsePrefix("169.254.255.254/32"), result, "coerceLinkLocal should bump broadcast 255.255 to 255.254")
+
+	result = coerceLinkLocal([]byte{169, 254, 0, 1})
+	assert.Equal(t, netip.MustParsePrefix("169.254.0.1/32"), result, "coerceLinkLocal should leave .1 last octet unchanged")
+
+	result = coerceLinkLocal([]byte{169, 254, 255, 254})
+	assert.Equal(t, netip.MustParsePrefix("169.254.255.254/32"), result, "coerceLinkLocal should leave 255.254 unchanged")
+
+	result = coerceLinkLocal([]byte{169, 254, 255, 100})
+	assert.Equal(t, netip.MustParsePrefix("169.254.255.100/32"), result, "coerceLinkLocal should leave 255.100 unchanged")
+}

overlay/tun_tester.go

@@ -17,18 +17,21 @@ import (
 )
 
 type TestTun struct {
-	Device      string
+	Device           string
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	Routes      []Route
+	unsafeNetworks   []netip.Prefix
-	routeTree   *bart.Table[routing.Gateways]
+	snatAddr         netip.Prefix
-	l           *logrus.Logger
+	unsafeIPv4Origin netip.Prefix
+	Routes           []Route
+	routeTree        *bart.Table[routing.Gateways]
+	l                *logrus.Logger
 
 	closed    atomic.Bool
 	rxPackets chan []byte // Packets to receive into nebula
 	TxPackets chan []byte // Packets transmitted outside by nebula
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*TestTun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*TestTun, error) {
 	_, routes, err := getAllRoutesFromConfig(c, vpnNetworks, true)
 	if err != nil {
 		return nil, err
@@ -38,18 +41,22 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		return nil, err
 	}
 
-	return &TestTun{
+	tt := &TestTun{
-		Device:      c.GetString("tun.dev", ""),
+		Device:         c.GetString("tun.dev", ""),
-		vpnNetworks: vpnNetworks,
+		vpnNetworks:    vpnNetworks,
-		Routes:      routes,
+		unsafeNetworks: unsafeNetworks,
-		routeTree:   routeTree,
+		Routes:         routes,
-		l:           l,
+		routeTree:      routeTree,
-		rxPackets:   make(chan []byte, 10),
+		l:              l,
-		TxPackets:   make(chan []byte, 10),
+		rxPackets:      make(chan []byte, 10),
-	}, nil
+		TxPackets:      make(chan []byte, 10),
+	}
+	tt.unsafeIPv4Origin = prepareUnsafeOriginAddr(tt, l, c, routes)
+	tt.snatAddr = prepareSnatAddr(tt, tt.l, c)
+	return tt, nil
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (*TestTun, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (*TestTun, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported")
 }
 
@@ -132,6 +139,22 @@ func (t *TestTun) Read(b []byte) (int, error) {
 	return len(p), nil
 }
 
+func (t *TestTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *TestTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented")
 }
+
+func (t *TestTun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *TestTun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *TestTun) SNATAddress() netip.Prefix {
+	return t.snatAddr
+}

overlay/tun_windows.go

@@ -28,21 +28,23 @@ import (
 const tunGUIDLabel = "Fixed Nebula Windows GUID v1"
 
 type winTun struct {
-	Device      string
+	Device           string
-	vpnNetworks []netip.Prefix
+	vpnNetworks      []netip.Prefix
-	MTU         int
+	unsafeNetworks   []netip.Prefix
-	Routes      atomic.Pointer[[]Route]
+	unsafeIPv4Origin netip.Prefix
-	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	MTU              int
-	l           *logrus.Logger
+	Routes           atomic.Pointer[[]Route]
+	routeTree        atomic.Pointer[bart.Table[routing.Gateways]]
+	l                *logrus.Logger
 
 	tun *wintun.NativeTun
 }
 
-func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix) (Device, error) {
+func newTunFromFd(_ *config.C, _ *logrus.Logger, _ int, _ []netip.Prefix, _ []netip.Prefix) (Device, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Windows")
 }
 
-func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (*winTun, error) {
+func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, _ bool) (*winTun, error) {
 	err := checkWinTunExists()
 	if err != nil {
 		return nil, fmt.Errorf("can not load the wintun driver: %w", err)
@@ -55,10 +57,11 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 	}
 
 	t := &winTun{
-		Device:      deviceName,
+		Device:         deviceName,
-		vpnNetworks: vpnNetworks,
+		vpnNetworks:    vpnNetworks,
-		MTU:         c.GetInt("tun.mtu", DefaultMTU),
+		unsafeNetworks: unsafeNetworks,
-		l:           l,
+		MTU:            c.GetInt("tun.mtu", DefaultMTU),
+		l:              l,
 	}
 
 	err = t.reload(c, true)
@@ -74,7 +77,10 @@ func newTun(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, _ bool) (
 		l.WithError(err).Debug("Failed to create wintun device, retrying")
 		tunDevice, err = wintun.CreateTUNWithRequestedGUID(deviceName, guid, t.MTU)
 		if err != nil {
-			return nil, fmt.Errorf("create TUN device failed: %w", err)
+			return nil, &NameError{
+				Name:       deviceName,
+				Underlying: fmt.Errorf("create TUN device failed: %w", err),
+			}
 		}
 	}
 	t.tun = tunDevice.(*wintun.NativeTun)
@@ -99,6 +105,10 @@ func (t *winTun) reload(c *config.C, initial bool) error {
 		return nil
 	}
 
+	if initial {
+		t.unsafeIPv4Origin = prepareUnsafeOriginAddr(t, t.l, c, routes)
+	}
+
 	routeTree, err := makeRouteTree(t.l, routes, false)
 	if err != nil {
 		return err
@@ -129,7 +139,12 @@ func (t *winTun) reload(c *config.C, initial bool) error {
 func (t *winTun) Activate() error {
 	luid := winipcfg.LUID(t.tun.LUID())
 
-	err := luid.SetIPAddresses(t.vpnNetworks)
+	prefixes := t.vpnNetworks
+	if t.unsafeIPv4Origin.IsValid() {
+		prefixes = append(prefixes, t.unsafeIPv4Origin)
+	}
+
+	err := luid.SetIPAddresses(prefixes)
 	if err != nil {
 		return fmt.Errorf("failed to set address: %w", err)
 	}
@@ -222,6 +237,18 @@ func (t *winTun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
 
+func (t *winTun) UnsafeNetworks() []netip.Prefix {
+	return t.unsafeNetworks
+}
+
+func (t *winTun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return t.unsafeIPv4Origin
+}
+
+func (t *winTun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (t *winTun) Name() string {
 	return t.Device
 }
@@ -234,6 +261,10 @@ func (t *winTun) Write(b []byte) (int, error) {
 	return t.tun.Write(b, 0)
 }
 
+func (t *winTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (t *winTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
 }

overlay/user.go

@@ -9,7 +9,7 @@ import (
 	"github.com/slackhq/nebula/routing"
 )
 
-func NewUserDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
+func NewUserDeviceFromConfig(c *config.C, l *logrus.Logger, vpnNetworks []netip.Prefix, unsafeNetworks []netip.Prefix, routines int) (Device, error) {
 	return NewUserDevice(vpnNetworks)
 }
 
@@ -36,6 +36,17 @@ type UserDevice struct {
 	inboundWriter *io.PipeWriter
 }
 
+func (d *UserDevice) UnsafeNetworks() []netip.Prefix {
+	return nil
+}
+
+func (d *UserDevice) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+func (d *UserDevice) UnsafeIPv4OriginAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (d *UserDevice) Activate() error {
 	return nil
 }
@@ -46,6 +57,10 @@ func (d *UserDevice) RoutesFor(ip netip.Addr) routing.Gateways {
 	return routing.Gateways{routing.NewGateway(ip, 1)}
 }
 
+func (d *UserDevice) SupportsMultiqueue() bool {
+	return true
+}
+
 func (d *UserDevice) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return d, nil
 }

pkclient/pkclient_cgo.go

@@ -180,6 +180,7 @@ func (c *PKClient) DeriveNoise(peerPubKey []byte) ([]byte, error) {
 		pkcs11.NewAttribute(pkcs11.CKA_DECRYPT, true),
 		pkcs11.NewAttribute(pkcs11.CKA_WRAP, true),
 		pkcs11.NewAttribute(pkcs11.CKA_UNWRAP, true),
+		pkcs11.NewAttribute(pkcs11.CKA_VALUE_LEN, NoiseKeySize),
 	}
 
 	// Set up the parameters which include the peer's public key

pki.go

@@ -91,7 +91,7 @@ func (p *PKI) reload(c *config.C, initial bool) error {
 }
 
 func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
-	newState, err := newCertStateFromConfig(c)
+	newState, err := newCertStateFromConfig(c, p.l)
 	if err != nil {
 		return util.NewContextualError("Could not load client cert", nil, err)
 	}
@@ -100,55 +100,70 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 		currentState := p.cs.Load()
 		if newState.v1Cert != nil {
 			if currentState.v1Cert == nil {
-				return util.NewContextualError("v1 certificate was added, restart required", nil, err)
+				//adding certs is fine, actually. Networks-in-common confirmed in newCertState().
-			}
+			} else {
+				// did IP in cert change? if so, don't set. If we ever allow this, need to set p.firewallReloadNeeded
+				if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
+					return util.NewContextualError(
+						"Networks in new cert was different from old",
+						m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks(), "cert_version": cert.Version1},
+						nil,
+					)
+				}
 
-			// did IP in cert change? if so, don't set
+				if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
-			if !slices.Equal(currentState.v1Cert.Networks(), newState.v1Cert.Networks()) {
+					return util.NewContextualError(
-				return util.NewContextualError(
+						"Curve in new v1 cert was different from old",
-					"Networks in new cert was different from old",
+						m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve(), "cert_version": cert.Version1},
-					m{"new_networks": newState.v1Cert.Networks(), "old_networks": currentState.v1Cert.Networks()},
+						nil,
-					nil,
+					)
-				)
+				}
 			}
-
-			if currentState.v1Cert.Curve() != newState.v1Cert.Curve() {
-				return util.NewContextualError(
-					"Curve in new cert was different from old",
-					m{"new_curve": newState.v1Cert.Curve(), "old_curve": currentState.v1Cert.Curve()},
-					nil,
-				)
-			}
-
-		} else if currentState.v1Cert != nil {
-			//TODO: CERT-V2 we should be able to tear this down
-			return util.NewContextualError("v1 certificate was removed, restart required", nil, err)
 		}
 
 		if newState.v2Cert != nil {
 			if currentState.v2Cert == nil {
-				return util.NewContextualError("v2 certificate was added, restart required", nil, err)
+				//adding certs is fine, actually
-			}
+			} else {
+				// did IP in cert change? if so, don't set
+				if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
+					return util.NewContextualError(
+						"Networks in new cert was different from old",
+						m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks(), "cert_version": cert.Version2},
+						nil,
+					)
+				}
 
-			// did IP in cert change? if so, don't set
+				if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
-			if !slices.Equal(currentState.v2Cert.Networks(), newState.v2Cert.Networks()) {
+					return util.NewContextualError(
-				return util.NewContextualError(
+						"Curve in new cert was different from old",
-					"Networks in new cert was different from old",
+						m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve(), "cert_version": cert.Version2},
-					m{"new_networks": newState.v2Cert.Networks(), "old_networks": currentState.v2Cert.Networks()},
+						nil,
-					nil,
+					)
-				)
+				}
-			}
-
-			if currentState.v2Cert.Curve() != newState.v2Cert.Curve() {
-				return util.NewContextualError(
-					"Curve in new cert was different from old",
-					m{"new_curve": newState.v2Cert.Curve(), "old_curve": currentState.v2Cert.Curve()},
-					nil,
-				)
 			}
 
 		} else if currentState.v2Cert != nil {
-			return util.NewContextualError("v2 certificate was removed, restart required", nil, err)
+			//newState.v1Cert is non-nil bc empty certstates aren't permitted
+			if newState.v1Cert == nil {
+				return util.NewContextualError("v1 and v2 certs are nil, this should be impossible", nil, err)
+			}
+			//if we're going to v1-only, we need to make sure we didn't orphan any v2-cert vpnaddrs
+			if !slices.Equal(currentState.v2Cert.Networks(), newState.v1Cert.Networks()) {
+				return util.NewContextualError(
+					"Removing a V2 cert is not permitted unless it has identical networks to the new V1 cert",
+					m{"new_v1_networks": newState.v1Cert.Networks(), "old_v2_networks": currentState.v2Cert.Networks()},
+					nil,
+				)
+			}
+		}
+
+		newUN := newState.GetDefaultCertificate().UnsafeNetworks()
+		oldUN := currentState.GetDefaultCertificate().UnsafeNetworks()
+		if !slices.Equal(newUN, oldUN) {
+			//todo I don't love this, because other clients will see the new assignments and act on them, but we will not be able to.
+			//I think we need to wire this into the firewall reload.
+			p.l.WithFields(m{"previous": oldUN, "new": newUN}).Warning("UnsafeNetworks assignments differ. A restart is required in order for this to take effect.")
 		}
 
 		// Cipher cant be hot swapped so just leave it at what it was before
@@ -173,7 +188,6 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 
 	p.cs.Store(newState)
 
-	//TODO: CERT-V2 newState needs a stringer that does json
 	if initial {
 		p.l.WithField("cert", newState).Debug("Client nebula certificate(s)")
 	} else {
@@ -254,7 +268,7 @@ func (cs *CertState) MarshalJSON() ([]byte, error) {
 	return json.Marshal(msg)
 }
 
-func newCertStateFromConfig(c *config.C) (*CertState, error) {
+func newCertStateFromConfig(c *config.C, l *logrus.Logger) (*CertState, error) {
 	var err error
 
 	privPathOrPEM := c.GetString("pki.key", "")
@@ -338,10 +352,33 @@ func newCertStateFromConfig(c *config.C) (*CertState, error) {
 		return nil, fmt.Errorf("unknown pki.initiating_version: %v", rawInitiatingVersion)
 	}
 
-	return newCertState(initiatingVersion, v1, v2, isPkcs11, curve, rawKey)
+	return newCertState(l, initiatingVersion, v1, v2, isPkcs11, curve, rawKey)
 }
 
-func newCertState(dv cert.Version, v1, v2 cert.Certificate, pkcs11backed bool, privateKeyCurve cert.Curve, privateKey []byte) (*CertState, error) {
+func compareUnsafeNetworksAcrossCertVersions(v1, v2 cert.Certificate) error {
+	if v1 == nil || v2 == nil {
+		return nil //can't be a problem if we don't have one of the kinds of cert
+	}
+
+	v4UnsafeNets := 0
+	for _, n := range v2.UnsafeNetworks() {
+		if n.Addr().Is6() {
+			continue // V1 certs can't have IPv6 unsafe networks
+		} else {
+			v4UnsafeNets++
+		}
+		if !slices.Contains(v1.UnsafeNetworks(), n) {
+			return errors.New("UnsafeNetworks mismatch")
+		}
+	}
+	if len(v1.UnsafeNetworks()) != v4UnsafeNets {
+		return errors.New("UnsafeNetworks mismatch")
+	}
+
+	return nil
+}
+
+func newCertState(l *logrus.Logger, dv cert.Version, v1, v2 cert.Certificate, pkcs11backed bool, privateKeyCurve cert.Curve, privateKey []byte) (*CertState, error) {
 	cs := CertState{
 		privateKey:               privateKey,
 		pkcs11Backed:             pkcs11backed,
@@ -359,9 +396,17 @@ func newCertState(dv cert.Version, v1, v2 cert.Certificate, pkcs11backed bool, p
 			return nil, util.NewContextualError("v1 and v2 curve are not the same, ignoring", nil, nil)
 		}
 
-		//TODO: CERT-V2 make sure v2 has v1s address
+		if v1.Networks()[0] != v2.Networks()[0] {
+			return nil, util.NewContextualError("v1 and v2 networks are not the same", nil, nil)
+		}
 
 		cs.initiatingVersion = dv
+
+		warn := compareUnsafeNetworksAcrossCertVersions(v1, v2)
+		if warn != nil {
+			l.WithFields(m{"UnsafeNetworksV1": v1.UnsafeNetworks(), "UnsafeNetworksV2": v2.UnsafeNetworks()}).
+				Warning("the IPv4 UnsafeNetworks assigned in the V1 certificate do not match the ones in V2")
+		}
 	}
 
 	if v1 != nil {
@@ -515,9 +560,13 @@ func loadCAPoolFromConfig(l *logrus.Logger, c *config.C) (*cert.CAPool, error) {
 		return nil, fmt.Errorf("error while adding CA certificate to CA trust store: %s", err)
 	}
 
-	for _, fp := range c.GetStringSlice("pki.blocklist", []string{}) {
+	bl := c.GetStringSlice("pki.blocklist", []string{})
-		l.WithField("fingerprint", fp).Info("Blocklisting cert")
+	if len(bl) > 0 {
-		caPool.BlocklistFingerprint(fp)
+		for _, fp := range bl {
+			caPool.BlocklistFingerprint(fp)
+		}
+
+		l.WithField("fingerprintCount", len(bl)).Info("Blocklisted certificates")
 	}
 
 	return caPool, nil

relay_manager.go

@@ -55,7 +55,7 @@ func (rm *relayManager) setAmRelay(v bool) {
 func AddRelay(l *logrus.Logger, relayHostInfo *HostInfo, hm *HostMap, vpnIp netip.Addr, remoteIdx *uint32, relayType int, state int) (uint32, error) {
 	hm.Lock()
 	defer hm.Unlock()
-	for i := 0; i < 32; i++ {
+	for range 32 {
 		index, err := generateIndex(l)
 		if err != nil {
 			return 0, err

remote_list.go

@@ -190,7 +190,7 @@ type RemoteList struct {
 	// The full list of vpn addresses assigned to this host
 	vpnAddrs []netip.Addr
 
-	// A deduplicated set of addresses. Any accessor should lock beforehand.
+	// A deduplicated set of underlay addresses. Any accessor should lock beforehand.
 	addrs []netip.AddrPort
 
 	// A set of relay addresses. VpnIp addresses that the remote identified as relays.
@@ -201,8 +201,10 @@ type RemoteList struct {
 	// For learned addresses, this is the vpnIp that sent the packet
 	cache map[netip.Addr]*cache
 
-	hr        *hostnamesResults
+	hr *hostnamesResults
-	shouldAdd func(netip.Addr) bool
+
+	// shouldAdd is a nillable function that decides if x should be added to addrs.
+	shouldAdd func(vpnAddrs []netip.Addr, x netip.Addr) bool
 
 	// This is a list of remotes that we have tried to handshake with and have returned from the wrong vpn ip.
 	// They should not be tried again during a handshake
@@ -213,7 +215,7 @@ type RemoteList struct {
 }
 
 // NewRemoteList creates a new empty RemoteList
-func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func(netip.Addr) bool) *RemoteList {
+func NewRemoteList(vpnAddrs []netip.Addr, shouldAdd func([]netip.Addr, netip.Addr) bool) *RemoteList {
 	r := &RemoteList{
 		vpnAddrs:  make([]netip.Addr, len(vpnAddrs)),
 		addrs:     make([]netip.AddrPort, 0),
@@ -336,21 +338,21 @@ func (r *RemoteList) CopyCache() *CacheMap {
 }
 
 // BlockRemote locks and records the address as bad, it will be excluded from the deduplicated address list
-func (r *RemoteList) BlockRemote(bad netip.AddrPort) {
+func (r *RemoteList) BlockRemote(bad ViaSender) {
-	if !bad.IsValid() {
+	if bad.IsRelayed {
-		// relays can have nil udp Addrs
 		return
 	}
+
 	r.Lock()
 	defer r.Unlock()
 
 	// Check if we already blocked this addr
-	if r.unlockedIsBad(bad) {
+	if r.unlockedIsBad(bad.UdpAddr) {
 		return
 	}
 
 	// We copy here because we are taking something else's memory and we can't trust everything
-	r.badRemotes = append(r.badRemotes, bad)
+	r.badRemotes = append(r.badRemotes, bad.UdpAddr)
 
 	// Mark the next interaction must recollect/dedupe
 	r.shouldRebuild = true
@@ -368,6 +370,15 @@ func (r *RemoteList) CopyBlockedRemotes() []netip.AddrPort {
 	return c
 }
 
+// RefreshFromHandshake locks and updates the RemoteList to account for data learned upon a completed handshake
+func (r *RemoteList) RefreshFromHandshake(vpnAddrs []netip.Addr) {
+	r.Lock()
+	r.badRemotes = nil
+	r.vpnAddrs = make([]netip.Addr, len(vpnAddrs))
+	copy(r.vpnAddrs, vpnAddrs)
+	r.Unlock()
+}
+
 // ResetBlockedRemotes locks and clears the blocked remotes list
 func (r *RemoteList) ResetBlockedRemotes() {
 	r.Lock()
@@ -393,12 +404,7 @@ func (r *RemoteList) Rebuild(preferredRanges []netip.Prefix) {
 
 // unlockedIsBad assumes you have the write lock and checks if the remote matches any entry in the blocked address list
 func (r *RemoteList) unlockedIsBad(remote netip.AddrPort) bool {
-	for _, v := range r.badRemotes {
+	return slices.Contains(r.badRemotes, remote)
-		if v == remote {
-			return true
-		}
-	}
-	return false
 }
 
 // unlockedSetLearnedV4 assumes you have the write lock and sets the current learned address for this owner and marks the
@@ -577,7 +583,7 @@ func (r *RemoteList) unlockedCollect() {
 
 	dnsAddrs := r.hr.GetAddrs()
 	for _, addr := range dnsAddrs {
-		if r.shouldAdd == nil || r.shouldAdd(addr.Addr()) {
+		if r.shouldAdd == nil || r.shouldAdd(r.vpnAddrs, addr.Addr()) {
 			if !r.unlockedIsBad(addr) {
 				addrs = append(addrs, addr)
 			}

routing/gateway.go

@@ -6,7 +6,7 @@ import (
 )
 
 const (
-	// Sentinal value
+	// Sentinel value
 	BucketNotCalculated = -1
 )
 

service/service_test.go

@@ -16,8 +16,8 @@ import (
 	"github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/overlay"
+	"go.yaml.in/yaml/v3"
 	"golang.org/x/sync/errgroup"
-	"gopkg.in/yaml.v3"
 )
 
 type m = map[string]any

snat.go

@@ -0,0 +1,91 @@
+package nebula
+
+import (
+	"encoding/binary"
+	"net/netip"
+)
+
+func recalcIPv4Checksum(data []byte, oldSrcIP netip.Addr, newSrcIP netip.Addr) {
+	oldChecksum := binary.BigEndian.Uint16(data[10:12])
+	//because of how checksums work, we can re-use this function
+	checksum := calcNewTransportChecksum(oldChecksum, oldSrcIP, 0, newSrcIP, 0)
+	binary.BigEndian.PutUint16(data[10:12], checksum)
+}
+
+func calcNewTransportChecksum(oldChecksum uint16, oldSrcIP netip.Addr, oldSrcPort uint16, newSrcIP netip.Addr, newSrcPort uint16) uint16 {
+	oldIP := binary.BigEndian.Uint32(oldSrcIP.AsSlice())
+	newIP := binary.BigEndian.Uint32(newSrcIP.AsSlice())
+
+	// Start with inverted checksum
+	checksum := uint32(^oldChecksum)
+
+	// Subtract old IP (as two 16-bit words)
+	checksum += uint32(^uint16(oldIP >> 16))
+	checksum += uint32(^uint16(oldIP & 0xFFFF))
+
+	// Subtract old port
+	checksum += uint32(^oldSrcPort)
+
+	// Add new IP (as two 16-bit words)
+	checksum += uint32(newIP >> 16)
+	checksum += uint32(newIP & 0xFFFF)
+
+	// Add new port
+	checksum += uint32(newSrcPort)
+
+	// Fold carries
+	for checksum > 0xFFFF {
+		checksum = (checksum & 0xFFFF) + (checksum >> 16)
+	}
+
+	// Return ones' complement
+	return ^uint16(checksum)
+}
+
+func recalcV4TransportChecksum(offsetInsideHeader int, data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
+	ipHeaderOffset := int(data[0]&0x0F) * 4
+	offset := ipHeaderOffset + offsetInsideHeader
+	oldcsum := binary.BigEndian.Uint16(data[offset : offset+2])
+	checksum := calcNewTransportChecksum(oldcsum, oldSrcIP.Addr(), oldSrcIP.Port(), newSrcIP.Addr(), newSrcIP.Port())
+	binary.BigEndian.PutUint16(data[offset:offset+2], checksum)
+}
+
+func recalcUDPv4Checksum(data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
+	const offsetInsideHeader = 6
+	recalcV4TransportChecksum(offsetInsideHeader, data, oldSrcIP, newSrcIP)
+}
+
+func recalcTCPv4Checksum(data []byte, oldSrcIP netip.AddrPort, newSrcIP netip.AddrPort) {
+	const offsetInsideHeader = 16
+	recalcV4TransportChecksum(offsetInsideHeader, data, oldSrcIP, newSrcIP)
+}
+
+func calcNewICMPChecksum(oldChecksum uint16, oldCode uint16, newCode uint16, oldID uint16, newID uint16) uint16 {
+	// Start with inverted checksum
+	checksum := uint32(^oldChecksum)
+
+	// Subtract old stuff
+	checksum += uint32(^oldCode)
+	checksum += uint32(^oldID)
+
+	// Add new stuff
+	checksum += uint32(newCode)
+	checksum += uint32(newID)
+
+	// Fold carries
+	for checksum > 0xFFFF {
+		checksum = (checksum & 0xFFFF) + (checksum >> 16)
+	}
+
+	// Return ones' complement
+	return ^uint16(checksum)
+}
+
+func recalcICMPv4Checksum(data []byte, oldCode uint16, newCode uint16, oldID uint16, newID uint16) {
+	const offsetInsideHeader = 2
+	ipHeaderOffset := int(data[0]&0x0F) * 4
+	offset := ipHeaderOffset + offsetInsideHeader
+	oldChecksum := binary.BigEndian.Uint16(data[offset : offset+2])
+	checksum := calcNewICMPChecksum(oldChecksum, oldCode, newCode, oldID, newID)
+	binary.BigEndian.PutUint16(data[offset:offset+2], checksum)
+}

ssh.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"maps"
 	"net"
 	"net/netip"
 	"os"
@@ -831,9 +832,7 @@ func sshPrintRelays(ifce *Interface, fs any, a []string, w sshd.StringWriter) er
 
 	relays := map[uint32]*HostInfo{}
 	ifce.hostMap.Lock()
-	for k, v := range ifce.hostMap.Relays {
+	maps.Copy(relays, ifce.hostMap.Relays)
-		relays[k] = v
-	}
 	ifce.hostMap.Unlock()
 
 	type RelayFor struct {

test/tun.go

@@ -10,6 +10,18 @@ import (
 
 type NoopTun struct{}
 
+func (NoopTun) UnsafeNetworks() []netip.Prefix {
+	return nil
+}
+
+func (NoopTun) SNATAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
+func (NoopTun) UnsafeIPv4OriginAddress() netip.Prefix {
+	return netip.Prefix{}
+}
+
 func (NoopTun) RoutesFor(addr netip.Addr) routing.Gateways {
 	return routing.Gateways{}
 }
@@ -34,6 +46,10 @@ func (NoopTun) Write([]byte) (int, error) {
 	return 0, nil
 }
 
+func (NoopTun) SupportsMultiqueue() bool {
+	return false
+}
+
 func (NoopTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	return nil, errors.New("unsupported")
 }

timeout_test.go

@@ -134,7 +134,7 @@ func TestTimerWheel_Purge(t *testing.T) {
 	assert.True(t, tw.lastTick.After(lastTick))
 
 	// Make sure we get all 4 packets back
-	for i := 0; i < 4; i++ {
+	for i := range 4 {
 		p, has := tw.Purge()
 		assert.True(t, has)
 		assert.Equal(t, fps[i], p)
@@ -149,7 +149,7 @@ func TestTimerWheel_Purge(t *testing.T) {
 	// Make sure we cached the free'd items
 	assert.Equal(t, 4, tw.itemsCached)
 	ci := tw.itemCache
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		assert.NotNil(t, ci)
 		ci = ci.Next
 	}

udp/conn.go

@@ -19,6 +19,7 @@ type Conn interface {
 	ListenOut(r EncReader)
 	WriteTo(b []byte, addr netip.AddrPort) error
 	ReloadConfig(c *config.C)
+	SupportsMultipleReaders() bool
 	Close() error
 }
 
@@ -33,6 +34,9 @@ func (NoopConn) LocalAddr() (netip.AddrPort, error) {
 func (NoopConn) ListenOut(_ EncReader) {
 	return
 }
+func (NoopConn) SupportsMultipleReaders() bool {
+	return false
+}
 func (NoopConn) WriteTo(_ []byte, _ netip.AddrPort) error {
 	return nil
 }

udp/errors.go

@@ -0,0 +1,5 @@
+package udp
+
+import "errors"
+
+var ErrInvalidIPv6RemoteForSocket = errors.New("listener is IPv4, but writing to IPv6 remote")

udp/udp_darwin.go

@@ -3,20 +3,62 @@
 
 package udp
 
-// Darwin support is primarily implemented in udp_generic, besides NewListenConfig
-
 import (
+	"context"
+	"encoding/binary"
+	"errors"
 	"fmt"
 	"net"
 	"net/netip"
 	"syscall"
+	"unsafe"
 
 	"github.com/sirupsen/logrus"
+	"github.com/slackhq/nebula/config"
 	"golang.org/x/sys/unix"
 )
 
+type StdConn struct {
+	*net.UDPConn
+	isV4  bool
+	sysFd uintptr
+	l     *logrus.Logger
+}
+
+var _ Conn = &StdConn{}
+
 func NewListener(l *logrus.Logger, ip netip.Addr, port int, multi bool, batch int) (Conn, error) {
-	return NewGenericListener(l, ip, port, multi, batch)
+	lc := NewListenConfig(multi)
+	pc, err := lc.ListenPacket(context.TODO(), "udp", net.JoinHostPort(ip.String(), fmt.Sprintf("%v", port)))
+	if err != nil {
+		return nil, err
+	}
+
+	if uc, ok := pc.(*net.UDPConn); ok {
+		c := &StdConn{UDPConn: uc, l: l}
+
+		rc, err := uc.SyscallConn()
+		if err != nil {
+			return nil, fmt.Errorf("failed to open udp socket: %w", err)
+		}
+
+		err = rc.Control(func(fd uintptr) {
+			c.sysFd = fd
+		})
+		if err != nil {
+			return nil, fmt.Errorf("failed to get udp fd: %w", err)
+		}
+
+		la, err := c.LocalAddr()
+		if err != nil {
+			return nil, err
+		}
+		c.isV4 = la.Addr().Is4()
+
+		return c, nil
+	}
+
+	return nil, fmt.Errorf("unexpected PacketConn: %T %#v", pc, pc)
 }
 
 func NewListenConfig(multi bool) net.ListenConfig {
@@ -43,16 +85,120 @@ func NewListenConfig(multi bool) net.ListenConfig {
 	}
 }
 
-func (u *GenericConn) Rebind() error {
+//go:linkname sendto golang.org/x/sys/unix.sendto
-	rc, err := u.UDPConn.SyscallConn()
+//go:noescape
-	if err != nil {
+func sendto(s int, buf []byte, flags int, to unsafe.Pointer, addrlen int32) (err error)
-		return err
+
+func (u *StdConn) WriteTo(b []byte, ap netip.AddrPort) error {
+	var sa unsafe.Pointer
+	var addrLen int32
+
+	if u.isV4 {
+		if ap.Addr().Is6() {
+			return ErrInvalidIPv6RemoteForSocket
+		}
+
+		var rsa unix.RawSockaddrInet4
+		rsa.Family = unix.AF_INET
+		rsa.Addr = ap.Addr().As4()
+		binary.BigEndian.PutUint16((*[2]byte)(unsafe.Pointer(&rsa.Port))[:], ap.Port())
+		sa = unsafe.Pointer(&rsa)
+		addrLen = syscall.SizeofSockaddrInet4
+	} else {
+		var rsa unix.RawSockaddrInet6
+		rsa.Family = unix.AF_INET6
+		rsa.Addr = ap.Addr().As16()
+		binary.BigEndian.PutUint16((*[2]byte)(unsafe.Pointer(&rsa.Port))[:], ap.Port())
+		sa = unsafe.Pointer(&rsa)
+		addrLen = syscall.SizeofSockaddrInet6
 	}
 
-	return rc.Control(func(fd uintptr) {
+	// Golang stdlib doesn't handle EAGAIN correctly in some situations so we do writes ourselves
-		err := syscall.SetsockoptInt(int(fd), unix.IPPROTO_IPV6, unix.IPV6_BOUND_IF, 0)
+	// See https://github.com/golang/go/issues/73919
-		if err != nil {
+	for {
-			u.l.WithError(err).Error("Failed to rebind udp socket")
+		//_, _, err := unix.Syscall6(unix.SYS_SENDTO, u.sysFd, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), 0, sa, addrLen)
+		err := sendto(int(u.sysFd), b, 0, sa, addrLen)
+		if err == nil {
+			// Written, get out before the error handling
+			return nil
 		}
-	})
+
+		if errors.Is(err, syscall.EINTR) {
+			// Write was interrupted, retry
+			continue
+		}
+
+		if errors.Is(err, syscall.EAGAIN) {
+			return &net.OpError{Op: "sendto", Err: unix.EWOULDBLOCK}
+		}
+
+		if errors.Is(err, syscall.EBADF) {
+			return net.ErrClosed
+		}
+
+		return &net.OpError{Op: "sendto", Err: err}
+	}
+}
+
+func (u *StdConn) LocalAddr() (netip.AddrPort, error) {
+	a := u.UDPConn.LocalAddr()
+
+	switch v := a.(type) {
+	case *net.UDPAddr:
+		addr, ok := netip.AddrFromSlice(v.IP)
+		if !ok {
+			return netip.AddrPort{}, fmt.Errorf("LocalAddr returned invalid IP address: %s", v.IP)
+		}
+		return netip.AddrPortFrom(addr, uint16(v.Port)), nil
+
+	default:
+		return netip.AddrPort{}, fmt.Errorf("LocalAddr returned: %#v", a)
+	}
+}
+
+func (u *StdConn) ReloadConfig(c *config.C) {
+	// TODO
+}
+
+func NewUDPStatsEmitter(udpConns []Conn) func() {
+	// No UDP stats for non-linux
+	return func() {}
+}
+
+func (u *StdConn) ListenOut(r EncReader) {
+	buffer := make([]byte, MTU)
+
+	for {
+		// Just read one packet at a time
+		n, rua, err := u.ReadFromUDPAddrPort(buffer)
+		if err != nil {
+			if errors.Is(err, net.ErrClosed) {
+				u.l.WithError(err).Debug("udp socket is closed, exiting read loop")
+				return
+			}
+
+			u.l.WithError(err).Error("unexpected udp socket receive error")
+		}
+
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
+	}
+}
+
+func (u *StdConn) SupportsMultipleReaders() bool {
+	return false
+}
+
+func (u *StdConn) Rebind() error {
+	var err error
+	if u.isV4 {
+		err = syscall.SetsockoptInt(int(u.sysFd), syscall.IPPROTO_IP, syscall.IP_BOUND_IF, 0)
+	} else {
+		err = syscall.SetsockoptInt(int(u.sysFd), syscall.IPPROTO_IPV6, syscall.IPV6_BOUND_IF, 0)
+	}
+
+	if err != nil {
+		u.l.WithError(err).Error("Failed to rebind udp socket")
+	}
+
+	return nil
 }