Bump github.com/gaissmai/bart from 0.28.0 to 0.29.0

Bumps [github.com/gaissmai/bart](https://github.com/gaissmai/bart) from 0.28.0 to 0.29.0.
- [Release notes](https://github.com/gaissmai/bart/releases)
- [Commits](https://github.com/gaissmai/bart/compare/v0.28.0...v0.29.0)

---
updated-dependencies:
- dependency-name: github.com/gaissmai/bart
  dependency-version: 0.29.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/release.yml

@@ -73,8 +73,11 @@ jobs:
   build-darwin:
     name: Build Universal Darwin
     env:
-      HAS_SIGNING_CREDS: ${{ secrets.AC_USERNAME != '' }}
+      HAS_SIGNING_CREDS: ${{ secrets.APPLE_SIGNING_ROLE_ARN != '' }}
     runs-on: macos-latest
+    permissions:
+      id-token: write
+      contents: read
     steps:
       - uses: actions/checkout@v7
 
@@ -83,17 +86,68 @@ jobs:
           go-version: '1.26'
           check-latest: true
 
+      # GitHub holds ARNs, not credentials, and ARNs outlive a rotation
+      - name: Configure AWS credentials
+        if: env.HAS_SIGNING_CREDS == 'true'
+        uses: aws-actions/configure-aws-credentials@v6
+        with:
+          role-to-assume: ${{ secrets.APPLE_SIGNING_ROLE_ARN }}
+          aws-region: us-east-2
+
+      # parse-json-secrets unpacks into SIGNING_* and ASC_*, masked on the way in
+      - name: Fetch signing credentials
+        if: env.HAS_SIGNING_CREDS == 'true'
+        uses: aws-actions/aws-secretsmanager-get-secrets@v3
+        with:
+          parse-json-secrets: true
+          secret-ids: |
+            SIGNING,${{ secrets.APPLE_SIGNING_DEVELOPER_ID_ARN }}
+            ASC,${{ secrets.APPLE_NOTARY_KEY_ARN }}
+
       - name: Import certificates
         if: env.HAS_SIGNING_CREDS == 'true'
         uses: Apple-Actions/import-codesign-certs@v7
         with:
-          p12-file-base64: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_P12_BASE64 }}
-          p12-password: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_PASSWORD }}
+          p12-file-base64: ${{ env.SIGNING_P12_BASE64 }}
+          p12-password: ${{ env.SIGNING_PASSWORD }}
+
+      # The action imports but does not check the chain validates, which is how a p12
+      # missing its intermediate reaches a failing codesign
+      - name: Check the identity is usable
+        if: env.HAS_SIGNING_CREDS == 'true'
+        run: |
+          : "${SIGNING_IDENTITY_SHA1:?empty, so the secret has no identity_sha1}"
+          identities=$(security find-identity -v -p codesigning signing_temp.keychain)
+          case "$identities" in
+          *"$SIGNING_IDENTITY_SHA1"*) ;;
+          *) printf '%s\n' "$identities" >&2; exit 1 ;;
+          esac
+
+      # notarytool wants the key as a file
+      - name: Write the App Store Connect key
+        if: env.HAS_SIGNING_CREDS == 'true'
+        run: |
+          mkdir -p ~/private_keys
+          chmod 700 ~/private_keys
+          key_path="$HOME/private_keys/AuthKey_${ASC_KEY_ID}.p8"
+          (umask 077; printf '%s\n' "$ASC_PRIVATE_KEY" > "$key_path")
+          echo "ASC_P8=$key_path" >> "$GITHUB_ENV"
+
+      - name: Drop the credentials from the environment
+        if: env.HAS_SIGNING_CREDS == 'true'
+        run: |
+          # The action's own inventory, so a new field in a secret is covered
+          python3 -c '
+          import json, os
+          raw = os.environ.get("SECRETS_LIST_CLEAN_UP")
+          if raw is None and os.environ.get("SIGNING_P12_BASE64"):
+              raise SystemExit("SECRETS_LIST_CLEAN_UP is gone, fetched secrets are not being scrubbed")
+          keep = {"SIGNING_IDENTITY_SHA1", "ASC_KEY_ID", "ASC_ISSUER_ID"}
+          names = [n for n in json.loads(raw or "[]") if n not in keep]
+          print("\n".join(f"{n}=" for n in dict.fromkeys(names)))
+          ' >> "$GITHUB_ENV"
 
       - name: Build, sign, and notarize
-        env:
-          AC_USERNAME: ${{ secrets.AC_USERNAME }}
-          AC_PASSWORD: ${{ secrets.AC_PASSWORD }}
         run: |
           rm -rf release
           mkdir release
@@ -102,17 +156,34 @@ jobs:
           lipo -create -output ./release/nebula ./build/darwin-amd64/nebula ./build/darwin-arm64/nebula
           lipo -create -output ./release/nebula-cert ./build/darwin-amd64/nebula-cert ./build/darwin-arm64/nebula-cert
 
-          if [ -n "$AC_USERNAME" ]; then
-            codesign -s "10BC1FDDEB6CE753550156C0669109FAC49E4D1E" -f -v --timestamp --options=runtime -i "net.defined.nebula" ./release/nebula
-            codesign -s "10BC1FDDEB6CE753550156C0669109FAC49E4D1E" -f -v --timestamp --options=runtime -i "net.defined.nebula-cert" ./release/nebula-cert
+          # Unset in a fork, which has no credentials to sign with
+          if [ -n "$SIGNING_IDENTITY_SHA1" ]; then
+            codesign -s "$SIGNING_IDENTITY_SHA1" -f -v --timestamp --options=runtime -i "net.defined.nebula" ./release/nebula
+            codesign -s "$SIGNING_IDENTITY_SHA1" -f -v --timestamp --options=runtime -i "net.defined.nebula-cert" ./release/nebula-cert
           fi
 
           zip -j release/nebula-darwin.zip release/nebula-cert release/nebula
 
-          if [ -n "$AC_USERNAME" ]; then
-            xcrun notarytool submit ./release/nebula-darwin.zip --team-id "576H3XS7FP" --apple-id "$AC_USERNAME" --password "$AC_PASSWORD" --wait
+          if [ -n "$ASC_P8" ]; then
+            xcrun notarytool submit ./release/nebula-darwin.zip --key "$ASC_P8" --key-id "$ASC_KEY_ID" --issuer "$ASC_ISSUER_ID" --wait
           fi
 
+      - name: Drop the signing key
+        if: always() && env.HAS_SIGNING_CREDS == 'true'
+        run: |
+          # Locked, not deleted: import-codesign-certs deletes it in its own post
+          # step and fails the job if it is already gone. Locked is unusable.
+          security lock-keychain signing_temp.keychain || true
+          rm -f "$ASC_P8"
+          # Nothing later in this job needs AWS
+          python3 -c '
+          import json, os
+          names = json.loads(os.environ.get("SECRETS_LIST_CLEAN_UP") or "[]")
+          names += ["ASC_P8", "SIGNING_IDENTITY_SHA1", "ASC_KEY_ID", "ASC_ISSUER_ID",
+                    "AWS_ACCESS_KEY_ID", "AWS_SECRET_ACCESS_KEY", "AWS_SESSION_TOKEN"]
+          print("\n".join(f"{n}=" for n in dict.fromkeys(names)))
+          ' >> "$GITHUB_ENV"
+
       - name: Upload artifacts
         uses: actions/upload-artifact@v7
         with:

connection_manager.go

@@ -323,6 +323,12 @@ func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Tim
 		return closeTunnel, hostinfo, nil
 	}
 
+	if hostinfo.ConnectionState != nil && hostinfo.ConnectionState.messageCounter.Load() >= RejectAfterMessages {
+		// Send path can't encrypt a CloseTunnel notify, so just delete locally; the peer recovers via recv_error.
+		hostinfo.logger(cm.l).Error("Dropping tunnel, message counter is exhausted")
+		return deleteTunnel, hostinfo, nil
+	}
+
 	primary := cm.hostMap.Hosts[hostinfo.vpnAddrs[0]]
 	mainHostInfo := true
 	if primary != nil && primary != hostinfo {
@@ -448,6 +454,11 @@ func (cm *connectionManager) shouldSwapPrimary(current *HostInfo) bool {
 		return false
 	}
 
+	if current.ConnectionState.messageCounter.Load() >= RehandshakeAfterMessages {
+		// This tunnel is being rolled for counter exhaustion, never swap back onto its spent key.
+		return false
+	}
+
 	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
@@ -544,6 +555,15 @@ func (cm *connectionManager) tryRehandshake(hostinfo *HostInfo) {
 			"reason", "current cert version < pki.initiatingVersion",
 		)
 
+		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
+		return
+	}
+	if hostinfo.ConnectionState.messageCounter.Load() >= RehandshakeAfterMessages {
+		cm.l.Info("Re-handshaking with remote",
+			"vpnAddrs", hostinfo.vpnAddrs,
+			"reason", "message counter rehandshake threshold reached",
+		)
+
 		cm.intf.handshakeManager.StartHandshake(hostinfo.vpnAddrs[0], nil)
 		return
 	}

connection_manager_test.go

@@ -199,6 +199,79 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 }
 
+func Test_NewConnectionManager_CounterLimits(t *testing.T) {
+	l := test.NewLogger()
+	localrange := netip.MustParsePrefix("10.1.1.1/24")
+	vpnIp := 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},
+		v1Credential:      nil,
+	}
+
+	lh := newTestLighthouse()
+	ifce := &Interface{
+		hostMap:          hostMap,
+		inside:           &overlaytest.NoopTun{},
+		outside:          &udp.NoopConn{},
+		firewall:         &Firewall{},
+		lightHouse:       lh,
+		pki:              &PKI{},
+		myVpnAddrs:       []netip.Addr{netip.MustParseAddr("172.1.1.1")}, // sorts below vpnIp so shouldSwapPrimary can proceed
+		handshakeManager: NewHandshakeManager(l, hostMap, lh, &udp.NoopConn{}, defaultHandshakeConfig),
+		l:                l,
+	}
+	ifce.pki.cs.Store(cs)
+
+	conf := config.NewC(test.NewLogger())
+	punchy := NewPunchyFromConfig(test.NewLogger(), conf, nil)
+	nc := newConnectionManagerFromConfig(test.NewLogger(), conf, hostMap, punchy)
+	nc.intf = ifce
+
+	hostinfo := &HostInfo{
+		vpnAddrs:      []netip.Addr{vpnIp},
+		localIndexId:  1099,
+		remoteIndexId: 9901,
+	}
+	hostinfo.ConnectionState = &ConnectionState{
+		myCert: &dummyCert{version: cert.Version1},
+	}
+	nc.hostMap.unlockedAddHostInfo(hostinfo, ifce)
+
+	// Below the rehandshake threshold, no handshake is started
+	hostinfo.ConnectionState.messageCounter.Store(RehandshakeAfterMessages - 1)
+	nc.tryRehandshake(hostinfo)
+	assert.Nil(t, ifce.handshakeManager.QueryVpnAddr(vpnIp))
+
+	// A tunnel on its current cert would normally swap to primary
+	assert.True(t, nc.shouldSwapPrimary(hostinfo))
+
+	// At the rehandshake threshold, a new handshake is started
+	hostinfo.ConnectionState.messageCounter.Store(RehandshakeAfterMessages)
+	nc.tryRehandshake(hostinfo)
+	assert.NotNil(t, ifce.handshakeManager.QueryVpnAddr(vpnIp))
+
+	// An exhausted tunnel being rolled must never swap back to primary onto its spent key
+	assert.False(t, nc.shouldSwapPrimary(hostinfo))
+
+	// Still below the reject limit, the tunnel stays up
+	nc.In(hostinfo)
+	decision, _, _ := nc.makeTrafficDecision(hostinfo.localIndexId, time.Now())
+	assert.Equal(t, tryRehandshake, decision)
+
+	// At the reject limit, the tunnel is deleted locally without a doomed CloseTunnel notify
+	hostinfo.ConnectionState.messageCounter.Store(RejectAfterMessages)
+	decision, _, _ = nc.makeTrafficDecision(hostinfo.localIndexId, time.Now())
+	assert.Equal(t, deleteTunnel, decision)
+}
+
 func Test_NewConnectionManager_DisconnectInactive(t *testing.T) {
 	l := test.NewLogger()
 	localrange := netip.MustParsePrefix("10.1.1.1/24")

connection_state.go

@@ -2,6 +2,7 @@ package nebula
 
 import (
 	"encoding/json"
+	"fmt"
 	"log/slog"
 	"sync"
 	"sync/atomic"
@@ -12,7 +13,18 @@ import (
 	"github.com/slackhq/nebula/noiseutil"
 )
 
-const ReplayWindow = 1024
+const (
+	ReplayWindow = 1024
+
+	// RehandshakeAfterMessages rolls keys inside the AES-GCM data-volume margin (~2^-36 advantage at 64KB frames).
+	RehandshakeAfterMessages = uint64(1) << 34
+
+	// RejectAfterMessages is the nonce ceiling enforced by noiseutil; a tunnel here is deleted locally, not notified.
+	RejectAfterMessages = noiseutil.RejectAfterMessages
+)
+
+// RehandshakeAfterMessages must stay below RejectAfterMessages so tunnels roll before the hard send stop.
+const _ = RejectAfterMessages - RehandshakeAfterMessages
 
 type ConnectionState struct {
 	eKey           noiseutil.CipherState
@@ -30,7 +42,12 @@ type ConnectionState struct {
 // completed handshake.Result. It seeds messageCounter and the replay window so
 // that the post-handshake message indices already used on the wire don't count
 // as missed traffic in the data plane.
-func newConnectionStateFromResult(r *handshake.Result) *ConnectionState {
+func newConnectionStateFromResult(r *handshake.Result) (*ConnectionState, error) {
+	// Refuse a MessageIndex too big for the replay window: it can only be a bug, and would spin the seed loop below.
+	if r.MessageIndex >= ReplayWindow {
+		return nil, fmt.Errorf("handshake message index %d exceeds replay window", r.MessageIndex)
+	}
+
 	ci := &ConnectionState{
 		myCert:    r.MyCert,
 		initiator: r.Initiator,
@@ -43,7 +60,7 @@ func newConnectionStateFromResult(r *handshake.Result) *ConnectionState {
 	for i := uint64(1); i <= r.MessageIndex; i++ {
 		ci.window.Update(nil, i)
 	}
-	return ci
+	return ci, nil
 }
 
 func (cs *ConnectionState) MarshalJSON() ([]byte, error) {
@@ -54,6 +71,16 @@ func (cs *ConnectionState) MarshalJSON() ([]byte, error) {
 	})
 }
 
+// NextMessageCounter reserves the next 1-based counter; RejectAfterMessages is the first we refuse, pinned to not wrap.
+func (cs *ConnectionState) NextMessageCounter() (uint64, bool) {
+	c := cs.messageCounter.Add(1)
+	if c >= RejectAfterMessages {
+		cs.messageCounter.Store(RejectAfterMessages)
+		return c, false
+	}
+	return c, true
+}
+
 func (cs *ConnectionState) Curve() cert.Curve {
 	return cs.myCert.Curve()
 }

connection_state_test.go

@@ -6,10 +6,12 @@ import (
 	"time"
 
 	"github.com/flynn/noise"
+	"github.com/rcrowley/go-metrics"
 	"github.com/slackhq/nebula/cert"
 	ct "github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/handshake"
 	"github.com/slackhq/nebula/header"
+	"github.com/slackhq/nebula/test"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -79,11 +81,51 @@ func runTestHandshake(t *testing.T) (initR, respR *handshake.Result) {
 	return initR, respR
 }
 
+func TestConnectionState_NextMessageCounter(t *testing.T) {
+	cs := &ConnectionState{}
+	cs.messageCounter.Store(RejectAfterMessages - 2)
+
+	c, ok := cs.NextMessageCounter()
+	assert.True(t, ok)
+	assert.Equal(t, RejectAfterMessages-1, c)
+
+	// Hitting the limit refuses and pins the counter there
+	c, ok = cs.NextMessageCounter()
+	assert.False(t, ok)
+	assert.Equal(t, RejectAfterMessages, c)
+	assert.Equal(t, RejectAfterMessages, cs.messageCounter.Load())
+
+	// Continued send attempts stay refused and the counter never wraps
+	for i := 0; i < 10; i++ {
+		_, ok = cs.NextMessageCounter()
+		assert.False(t, ok)
+	}
+	assert.Equal(t, RejectAfterMessages, cs.messageCounter.Load())
+}
+
+// TestSendNoMetricsDropsExhausted drives the send path to the exhausted drop; metric and out flag prove it.
+func TestSendNoMetricsDropsExhausted(t *testing.T) {
+	initR, _ := runTestHandshake(t)
+	ci, err := newConnectionStateFromResult(initR)
+	require.NoError(t, err)
+	ci.messageCounter.Store(RejectAfterMessages - 1)
+
+	f := &Interface{l: test.NewLogger(), messageMetrics: &MessageMetrics{txExhausted: metrics.NewCounter()}}
+	hostinfo := &HostInfo{vpnAddrs: []netip.Addr{netip.MustParseAddr("10.0.0.1")}, ConnectionState: ci}
+
+	f.sendNoMetrics(header.Message, 0, ci, hostinfo, netip.AddrPort{}, []byte{}, make([]byte, 12), make([]byte, mtu), 0)
+
+	// The crossing send is refused: it records an exhaustion drop and never reaches connectionManager.Out.
+	assert.Equal(t, int64(1), f.messageMetrics.txExhausted.Count())
+	assert.False(t, hostinfo.out.Load())
+}
+
 func TestNewConnectionStateFromResult(t *testing.T) {
 	initR, respR := runTestHandshake(t)
 
 	t.Run("initiator", func(t *testing.T) {
-		ci := newConnectionStateFromResult(initR)
+		ci, err := newConnectionStateFromResult(initR)
+		require.NoError(t, err)
 		assert.True(t, ci.initiator)
 		assert.Equal(t, initR.MyCert, ci.myCert)
 		assert.Equal(t, initR.RemoteCert, ci.peerCert)
@@ -102,8 +144,17 @@ func TestNewConnectionStateFromResult(t *testing.T) {
 		assert.True(t, ci.window.Check(nil, 3), "counter 3 must not be pre-seeded")
 	})
 
+	t.Run("message index too large is refused", func(t *testing.T) {
+		bad := *initR
+		bad.MessageIndex = ReplayWindow
+		ci, err := newConnectionStateFromResult(&bad)
+		require.Error(t, err)
+		assert.Nil(t, ci)
+	})
+
 	t.Run("responder", func(t *testing.T) {
-		ci := newConnectionStateFromResult(respR)
+		ci, err := newConnectionStateFromResult(respR)
+		require.NoError(t, err)
 		assert.False(t, ci.initiator)
 		assert.Equal(t, respR.MyCert, ci.myCert)
 		assert.Equal(t, respR.RemoteCert, ci.peerCert)

e2e/recovery_timing_test.go

@@ -0,0 +1,136 @@
+//go:build e2e_testing
+// +build e2e_testing
+
+package e2e
+
+import (
+	"testing"
+	"time"
+
+	"github.com/slackhq/nebula"
+	"github.com/slackhq/nebula/cert"
+	"github.com/slackhq/nebula/cert_test"
+	"github.com/slackhq/nebula/e2e/router"
+	"github.com/slackhq/nebula/udp"
+)
+
+// TestRecoveryTiming measures how long a tunnel takes to come back after the peer stops accepting our traffic,
+// which is what a laptop waking on a new network looks like from the peer's side: its NAT has no state for where
+// we are now, so everything we send disappears.
+//
+// It is a measurement, not a pass/fail assertion. Recovery is timed to the moment the peer punches back at us,
+// since that is when its NAT opens and the tunnel is usable again.
+//
+//	go test -tags e2e_testing -v -run TestRecoveryTiming ./e2e/
+func TestRecoveryTiming(t *testing.T) {
+	for _, tc := range []struct {
+		name   string
+		rebind bool
+	}{
+		{"no trigger", false},
+		{"rebind counter", true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			d, lost := measureRecovery(t, tc.rebind)
+			t.Logf("RESULT %-16s recovered in %-9v (%d packets lost)", tc.name, d.Round(time.Millisecond), lost)
+		})
+	}
+}
+
+// measureRecovery returns how long until the peer punched back, and how many of our packets died meanwhile. When
+// rebind is true we call RebindUDPServer once the tunnel goes dark, which is what the darwin network change
+// monitor does and what iOS has always done. When false, nothing tells nebula anything is wrong.
+func measureRecovery(t *testing.T, rebind bool) (time.Duration, int) {
+	t.Helper()
+	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", "10.128.0.1/24", m{
+		"lighthouse": m{"am_lighthouse": true},
+	})
+
+	peerCfg := m{
+		"lighthouse": m{
+			"hosts":    []any{lhVpnIpNet[0].Addr().String()},
+			"interval": 600,
+			"local_allow_list": m{
+				"10.0.0.0/24": true,
+				"::/0":        false,
+			},
+		},
+		"static_host_map": m{
+			lhVpnIpNet[0].Addr().String(): []any{lhUdpAddr.String()},
+		},
+	}
+
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "me", "10.128.0.2/24", peerCfg)
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "them", "10.128.0.3/24", peerCfg)
+
+	r := router.NewR(t, lhControl, myControl, theirControl)
+	defer r.RenderFlow()
+	defer func() {
+		lhControl.Stop()
+		myControl.Stop()
+		theirControl.Stop()
+	}()
+
+	lhControl.Start()
+	myControl.Start()
+	theirControl.Start()
+	r.RouteFor(time.Millisecond * 500)
+
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	myControl.InjectTunPacket(BuildTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("establish")))
+	r.RouteFor(time.Second)
+	if myControl.GetHostInfoByVpnAddr(theirVpnIpNet[0].Addr(), false) == nil {
+		t.Fatal("failed to establish the tunnel we are measuring")
+	}
+	r.RouteFor(time.Millisecond * 500)
+
+	// From here the peer's NAT has no state for us, everything we send it disappears
+	start := time.Now()
+	blackholed := 0
+	var recovered time.Duration
+
+	if rebind {
+		myControl.RebindUDPServer()
+	}
+
+	// Keep the tun busy the way someone retrying a stalled connection would
+	stop := make(chan struct{})
+	defer close(stop)
+	go func() {
+		tick := time.NewTicker(time.Millisecond * 200)
+		defer tick.Stop()
+		for {
+			select {
+			case <-stop:
+				return
+			case <-tick.C:
+				myControl.InjectTunPacket(BuildTunUDPPacket(
+					theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("retry")))
+			}
+		}
+	}()
+
+	r.RouteForAllExitFuncOrTimeout(time.Second*30, func(p *udp.Packet, c *nebula.Control) router.ExitType {
+		if c == theirControl && p.From == myControl.GetUDPAddr() {
+			blackholed++
+			return router.Drop
+		}
+
+		// The peer reaching us directly is the moment its NAT opened, whether that is a punch or a handshake
+		if c == myControl && p.From == theirUdpAddr {
+			recovered = time.Since(start)
+			return router.RouteAndExit
+		}
+
+		return router.KeepRouting
+	})
+
+	if recovered == 0 {
+		t.Fatalf("no recovery within 30s (%d packets blackholed)", blackholed)
+	}
+	return recovered, blackholed
+}

e2e/router/router.go

@@ -6,11 +6,13 @@ package router
 import (
 	"context"
 	"fmt"
+	"maps"
 	"net/netip"
 	"os"
 	"path/filepath"
 	"reflect"
 	"regexp"
+	"slices"
 	"sort"
 	"sync"
 	"sync/atomic"
@@ -22,7 +24,6 @@ import (
 	"github.com/slackhq/nebula"
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/udp"
-	"golang.org/x/exp/maps"
 )
 
 // outNatKey is the (from, to) pair used by outNat. Comparable struct, so it works as a map key without the
@@ -153,6 +154,9 @@ const (
 	ExitNow ExitType = 1
 	// RouteAndExit routes this packet and exits immediately afterwards
 	RouteAndExit ExitType = 2
+	// Drop discards this packet without delivering it and keeps routing. Use it to simulate a blackhole, such as
+	// a restrictive NAT refusing traffic from an address it has not seen.
+	Drop ExitType = 3
 )
 
 type ExitFunc func(packet *udp.Packet, receiver *nebula.Control) ExitType
@@ -163,7 +167,9 @@ type ExitFunc func(packet *udp.Packet, receiver *nebula.Control) ExitType
 func NewR(t testing.TB, controls ...*nebula.Control) *R {
 	ctx, cancel := context.WithCancel(context.Background())
 
-	if err := os.MkdirAll("mermaid", 0755); err != nil {
+	// t.Name() contains a slash for subtests, so the flow log can land in a nested directory
+	fn := filepath.Join("mermaid", fmt.Sprintf("%s.md", t.Name()))
+	if err := os.MkdirAll(filepath.Dir(fn), 0755); err != nil {
 		panic(err)
 	}
 
@@ -174,7 +180,7 @@ func NewR(t testing.TB, controls ...*nebula.Control) *R {
 		outNat:       make(map[outNatKey]netip.AddrPort),
 		flow:         []flowEntry{},
 		ignoreFlows:  []ignoreFlow{},
-		fn:           filepath.Join("mermaid", fmt.Sprintf("%s.md", t.Name())),
+		fn:           fn,
 		t:            t,
 		cancelRender: cancel,
 	}
@@ -369,7 +375,7 @@ func (r *R) RenderHostmaps(title string, controls ...*nebula.Control) {
 }
 
 func (r *R) renderHostmaps(title string) {
-	c := maps.Values(r.controls)
+	c := slices.AppendSeq(make([]*nebula.Control, 0, len(r.controls)), maps.Values(r.controls))
 	sort.SliceStable(c, func(i, j int) bool {
 		return c[i].GetVpnAddrs()[0].Compare(c[j].GetVpnAddrs()[0]) > 0
 	})
@@ -687,6 +693,10 @@ func (r *R) RouteExitFunc(sender *nebula.Control, whatDo ExitFunc) {
 			p.Release()
 			return
 
+		case Drop:
+			// Record it so the flow log shows the attempt, but never hand it to the receiver
+			r.unlockedInjectFlow(sender, receiver, p, false)
+
 		case KeepRouting:
 			fp := r.unlockedInjectFlow(sender, receiver, p, false)
 			receiver.InjectUDPPacket(p)
@@ -779,6 +789,10 @@ func (r *R) RouteForAllExitFuncOrTimeout(timeout time.Duration, whatDo ExitFunc)
 			p.Release()
 			return true
 
+		case Drop:
+			// Record it so the flow log shows the attempt, but never hand it to the receiver
+			r.unlockedInjectFlow(cm[x], receiver, p, false)
+
 		case KeepRouting:
 			fp := r.unlockedInjectFlow(cm[x], receiver, p, false)
 			receiver.InjectUDPPacket(p)
@@ -884,6 +898,10 @@ func (r *R) RouteForAllExitFunc(whatDo ExitFunc) {
 			p.Release()
 			return
 
+		case Drop:
+			// Record it so the flow log shows the attempt, but never hand it to the receiver
+			r.unlockedInjectFlow(cm[x], receiver, p, false)
+
 		case KeepRouting:
 			fp := r.unlockedInjectFlow(cm[x], receiver, p, false)
 			receiver.InjectUDPPacket(p)

go.mod

@@ -7,25 +7,23 @@ require (
 	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 v0.28.0
+	github.com/gaissmai/bart v0.29.0
 	github.com/gogo/protobuf v1.3.2
 	github.com/google/gopacket v1.1.19
 	github.com/kardianos/service v1.3.0
 	github.com/miekg/dns v1.1.72
 	github.com/miekg/pkcs11 v1.1.2
 	github.com/nbrownus/go-metrics-prometheus v0.0.0-20210712211119-974a6260965f
-	github.com/prometheus/client_golang v1.23.2
+	github.com/prometheus/client_golang v1.24.1
 	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/stefanberger/go-pkcs11uri v0.0.0-20230803200340-78284954bff6
-	github.com/stretchr/testify v1.11.1
+	github.com/stretchr/testify v1.12.0
 	github.com/vishvananda/netlink v1.3.1
 	go.uber.org/goleak v1.3.0
-	go.yaml.in/yaml/v3 v3.0.4
+	go.yaml.in/yaml/v3 v3.0.5
 	golang.org/x/crypto v0.54.0
-	golang.org/x/exp v0.0.0-20230725093048-515e97ebf090
 	golang.org/x/net v0.57.0
 	golang.org/x/sync v0.22.0
 	golang.org/x/sys v0.47.0
@@ -41,15 +39,12 @@ require (
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	github.com/davecgh/go-spew v1.1.1 // indirect
 	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 v0.6.2 // indirect
-	github.com/prometheus/common v0.66.1 // indirect
-	github.com/prometheus/procfs v0.16.1 // indirect
+	github.com/prometheus/common v0.70.1 // indirect
+	github.com/prometheus/procfs v0.21.1 // indirect
 	github.com/vishvananda/netns v0.0.5 // indirect
-	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/mod v0.36.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
 	golang.org/x/tools v0.45.0 // indirect

go.sum

@@ -19,15 +19,12 @@ github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6r
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432 h1:M5QgkYacWj0Xs8MhpIK/5uwU02icXpEoSo9sM2aRCps=
-github.com/cyberdelia/go-metrics-graphite v0.0.0-20161219230853-39f87cc3b432/go.mod h1:xwIwAxMvYnVrGJPe2FKx5prTrnAjGOD8zvDOnxnrrkM=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-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 v0.28.0 h1:89yZLo8NmyqD0RYgJ3QO9HhqqGGw+oWhf90cZm69Lko=
-github.com/gaissmai/bart v0.28.0/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
+github.com/gaissmai/bart v0.29.0 h1:wO6HGE8g9YE0Wm0bCpYxwRzfQ4+fbJKOhL64e5ACGCI=
+github.com/gaissmai/bart v0.29.0/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=
@@ -70,15 +67,14 @@ github.com/kardianos/service v1.3.0 h1:/LGy+xPP2TM+GLTiCZ2di7cy0Jd/qrawlTUfqKYFd
 github.com/kardianos/service v1.3.0/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=
-github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
+github.com/klauspost/compress v1.19.1 h1:VsB4HPswih7mmZ8WleSFQ75c/Ui1M4trX5oAsJnhSlk=
+github.com/klauspost/compress v1.19.1/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
-github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
-github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
@@ -102,14 +98,13 @@ github.com/nbrownus/go-metrics-prometheus v0.0.0-20210712211119-974a6260965f/go.
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v1.0.0/go.mod h1:db9x61etRT2tGnBNRi70OPL5FsnadC4Ky3P0J6CfImo=
 github.com/prometheus/client_golang v1.7.1/go.mod h1:PY5Wy2awLA44sXw4AOSfFBetzPP4j5+D6mVACh+pe2M=
 github.com/prometheus/client_golang v1.11.0/go.mod h1:Z6t4BnS23TR94PD6BsDNk8yVqroYurpAkEiz0P2BEV0=
-github.com/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
-github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
+github.com/prometheus/client_golang v1.24.1 h1:JnJkREXzWxUdCuPFpIWZiPispT9xVV59uiuyR2bPlnU=
+github.com/prometheus/client_golang v1.24.1/go.mod h1:F+oSRECHg4sse5ucfYpYDeIv/hu68Zo0uoHKetWnzcE=
 github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
 github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
 github.com/prometheus/client_model v0.2.0/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
@@ -118,18 +113,16 @@ github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvM
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.10.0/go.mod h1:Tlit/dnDKsSWFlCLTWaA1cyBgKHSMdTB80sz/V91rCo=
 github.com/prometheus/common v0.26.0/go.mod h1:M7rCNAaPfAosfx8veZJCuw84e35h3Cfd9VFqTh1DIvc=
-github.com/prometheus/common v0.66.1 h1:h5E0h5/Y8niHc5DlaLlWLArTQI7tMrsfQjHV+d9ZoGs=
-github.com/prometheus/common v0.66.1/go.mod h1:gcaUsgf3KfRSwHY4dIMXLPV0K/Wg1oZ8+SbZk/HH/dA=
+github.com/prometheus/common v0.70.1 h1:1HvjP4D5oL3t8RsPlwxA9onvvStjtIHYE5XuuwOi/PY=
+github.com/prometheus/common v0.70.1/go.mod h1:VdFUQDMZK3VLkurFUVhia6uys/0suUp86TJz5qbJRhc=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/procfs v0.1.3/go.mod h1:lV6e/gmhEcM9IjHGsFOCxxuZ+z1YqCvr4OA4YeYWdaU=
 github.com/prometheus/procfs v0.6.0/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1xBZuNvfVA=
-github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
-github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
+github.com/prometheus/procfs v0.21.1 h1:GljZCt+zSTS+NZq88cyQ1LjZ+RCHp3uVuabBWA5+OJI=
+github.com/prometheus/procfs v0.21.1/go.mod h1:aB55Cww9pdSJVHk0hUf0inxWyyjPogFIjmHKYgMKmtY=
 github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 h1:N/ElC8H3+5XpJzTSTfLsJV/mx9Q9g7kxmchpfZyxgzM=
 github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
-github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
-github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
@@ -143,8 +136,8 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
-github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+github.com/stretchr/testify v1.12.0 h1:K6Mr6jO9JICuend/5xzTM03ydSV3vdNRYAdPSukj8uI=
+github.com/stretchr/testify v1.12.0/go.mod h1:bOYBZb5qJ00vPzWfIqBUZPaxK8jWiXc6d3ErP4Ca9Gw=
 github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW6bV0=
 github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
 github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
@@ -153,10 +146,10 @@ github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9de
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
-go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
-go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
-go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
-go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+go.yaml.in/yaml/v2 v2.4.4 h1:tuyd0P+2Ont/d6e2rl3be67goVK4R6deVxCUX5vyPaQ=
+go.yaml.in/yaml/v2 v2.4.4/go.mod h1:gMZqIpDtDqOfM0uNfy0SkpRhvUryYH0Z6wdMYcacYXQ=
+go.yaml.in/yaml/v3 v3.0.5 h1:N6y/pJk8buWs9NY5ERU2HSMfm+IuD/OtfdAnq6kESPw=
+go.yaml.in/yaml/v3 v3.0.5/go.mod h1:HVTZu1O7/Vkt2N+BFy8Zza+lnLsABggaTM2ZpNIGuKg=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
@@ -164,8 +157,6 @@ golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPh
 golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
 golang.org/x/crypto v0.54.0 h1:YLIA59K4fiNzHzjnZt2tUJQjQtUWfWbeHBqKtk3eScw=
 golang.org/x/crypto v0.54.0/go.mod h1:KWL8ny2AZdGR2cWmzeHrp2azQPGogOv+HeQaVEXC2dk=
-golang.org/x/exp v0.0.0-20230725093048-515e97ebf090 h1:Di6/M8l0O2lCLc6VVRWhgCiApHV8MnQurBnFSHsQtNY=
-golang.org/x/exp v0.0.0-20230725093048-515e97ebf090/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
 golang.org/x/lint v0.0.0-20200302205851-738671d3881b/go.mod h1:3xt1FjdF8hUf6vQPIChWIBhFzV8gjjsPE/fR3IyQdNY=
 golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=

graphite.go

@@ -0,0 +1,117 @@
+package nebula
+
+// This file is a trimmed, inlined copy of the graphite exporter from
+// github.com/cyberdelia/go-metrics-graphite, retaining only the Config type and
+// the Once entrypoint that Nebula uses. The upstream package has been
+// unmaintained for 10+ years, so it was vendored here to drop the dependency.
+// See https://github.com/slackhq/nebula/issues/1831.
+//
+// Copyright 2015 Timothée Peignier. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+//  1. Redistributions of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//  2. Redistributions in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/rcrowley/go-metrics"
+)
+
+// graphiteConfigExport provides a container with configuration parameters for
+// the Graphite exporter.
+type graphiteConfigExport struct {
+	Addr          *net.TCPAddr     // Network address to connect to
+	Registry      metrics.Registry // Registry to be exported
+	FlushInterval time.Duration    // Flush interval
+	DurationUnit  time.Duration    // Time conversion unit for durations
+	Prefix        string           // Prefix to be prepended to metric names
+	Percentiles   []float64        // Percentiles to export from timers and histograms
+}
+
+// graphiteOnce performs a single submission to Graphite, returning a non-nil
+// error on failed connections.
+func graphiteOnce(c graphiteConfigExport) error {
+	now := time.Now().Unix()
+	du := float64(c.DurationUnit)
+	flushSeconds := float64(c.FlushInterval) / float64(time.Second)
+	conn, err := net.DialTCP("tcp", nil, c.Addr)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+	w := bufio.NewWriter(conn)
+	c.Registry.Each(func(name string, i any) {
+		switch metric := i.(type) {
+		case metrics.Counter:
+			count := metric.Count()
+			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, count, now)
+			fmt.Fprintf(w, "%s.%s.count_ps %.2f %d\n", c.Prefix, name, float64(count)/flushSeconds, now)
+		case metrics.Gauge:
+			fmt.Fprintf(w, "%s.%s.value %d %d\n", c.Prefix, name, metric.Value(), now)
+		case metrics.GaugeFloat64:
+			fmt.Fprintf(w, "%s.%s.value %f %d\n", c.Prefix, name, metric.Value(), now)
+		case metrics.Histogram:
+			h := metric.Snapshot()
+			ps := h.Percentiles(c.Percentiles)
+			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, h.Count(), now)
+			fmt.Fprintf(w, "%s.%s.min %d %d\n", c.Prefix, name, h.Min(), now)
+			fmt.Fprintf(w, "%s.%s.max %d %d\n", c.Prefix, name, h.Max(), now)
+			fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, h.Mean(), now)
+			fmt.Fprintf(w, "%s.%s.std-dev %.2f %d\n", c.Prefix, name, h.StdDev(), now)
+			for psIdx, psKey := range c.Percentiles {
+				key := strings.Replace(strconv.FormatFloat(psKey*100.0, 'f', -1, 64), ".", "", 1)
+				fmt.Fprintf(w, "%s.%s.%s-percentile %.2f %d\n", c.Prefix, name, key, ps[psIdx], now)
+			}
+		case metrics.Meter:
+			m := metric.Snapshot()
+			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, m.Count(), now)
+			fmt.Fprintf(w, "%s.%s.one-minute %.2f %d\n", c.Prefix, name, m.Rate1(), now)
+			fmt.Fprintf(w, "%s.%s.five-minute %.2f %d\n", c.Prefix, name, m.Rate5(), now)
+			fmt.Fprintf(w, "%s.%s.fifteen-minute %.2f %d\n", c.Prefix, name, m.Rate15(), now)
+			fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, m.RateMean(), now)
+		case metrics.Timer:
+			t := metric.Snapshot()
+			ps := t.Percentiles(c.Percentiles)
+			count := t.Count()
+			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, count, now)
+			fmt.Fprintf(w, "%s.%s.count_ps %.2f %d\n", c.Prefix, name, float64(count)/flushSeconds, now)
+			fmt.Fprintf(w, "%s.%s.min %d %d\n", c.Prefix, name, t.Min()/int64(du), now)
+			fmt.Fprintf(w, "%s.%s.max %d %d\n", c.Prefix, name, t.Max()/int64(du), now)
+			fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, t.Mean()/du, now)
+			fmt.Fprintf(w, "%s.%s.std-dev %.2f %d\n", c.Prefix, name, t.StdDev()/du, now)
+			for psIdx, psKey := range c.Percentiles {
+				key := strings.Replace(strconv.FormatFloat(psKey*100.0, 'f', -1, 64), ".", "", 1)
+				fmt.Fprintf(w, "%s.%s.%s-percentile %.2f %d\n", c.Prefix, name, key, ps[psIdx]/du, now)
+			}
+			fmt.Fprintf(w, "%s.%s.one-minute %.2f %d\n", c.Prefix, name, t.Rate1(), now)
+			fmt.Fprintf(w, "%s.%s.five-minute %.2f %d\n", c.Prefix, name, t.Rate5(), now)
+			fmt.Fprintf(w, "%s.%s.fifteen-minute %.2f %d\n", c.Prefix, name, t.Rate15(), now)
+			fmt.Fprintf(w, "%s.%s.mean-rate %.2f %d\n", c.Prefix, name, t.RateMean(), now)
+		}
+		w.Flush()
+	})
+	return nil
+}

handshake_manager.go

@@ -749,8 +749,14 @@ func (hm *HandshakeManager) beginHandshake(via ViaSender, packet []byte, h *head
 		return
 	}
 
+	connState, err := newConnectionStateFromResult(result)
+	if err != nil {
+		f.l.Error("Discarding handshake with an invalid message index", "error", err, "vpnAddrs", vpnAddrs)
+		return
+	}
+
 	hostinfo := &HostInfo{
-		ConnectionState:   newConnectionStateFromResult(result),
+		ConnectionState:   connState,
 		localIndexId:      result.LocalIndex,
 		remoteIndexId:     result.RemoteIndex,
 		vpnAddrs:          vpnAddrs,
@@ -868,7 +874,13 @@ func (hm *HandshakeManager) continueHandshake(via ViaSender, hh *HandshakeHostIn
 	}
 
 	// Handshake complete; build the ConnectionState now that we have keys and a verified peer cert.
-	hostinfo.ConnectionState = newConnectionStateFromResult(result)
+	cs, err := newConnectionStateFromResult(result)
+	if err != nil {
+		f.l.Error("Discarding handshake with an invalid message index", "error", err, "vpnAddrs", hostinfo.vpnAddrs)
+		hm.DeleteHostInfo(hostinfo)
+		return
+	}
+	hostinfo.ConnectionState = cs
 
 	remoteCert := result.RemoteCert
 	if remoteCert == nil {

inside.go

@@ -275,6 +275,14 @@ func (f *Interface) sendTo(t header.MessageType, st header.MessageSubType, ci *C
 	f.sendNoMetrics(t, st, ci, hostinfo, remote, p, nb, out, 0)
 }
 
+// dropExhausted records an exhaustion drop and logs once, on the crossing send, for a spent tunnel.
+func (f *Interface) dropExhausted(hostinfo *HostInfo, c uint64, msg string) {
+	f.messageMetrics.TxExhausted(1)
+	if c == RejectAfterMessages {
+		hostinfo.logger(f.l).Error(msg)
+	}
+}
+
 // SendVia sends a payload through a Relay tunnel. No authentication or encryption is done
 // to the payload for the ultimate target host, making this a useful method for sending
 // handshake messages to peers through relay tunnels.
@@ -294,7 +302,14 @@ func (f *Interface) SendVia(via *HostInfo,
 		// NOTE: for goboring AESGCMTLS we need to lock because of the nonce check
 		via.ConnectionState.writeLock.Lock()
 	}
-	c := via.ConnectionState.messageCounter.Add(1)
+	c, ok := via.ConnectionState.NextMessageCounter()
+	if !ok {
+		if noiseutil.EncryptLockNeeded {
+			via.ConnectionState.writeLock.Unlock()
+		}
+		f.dropExhausted(via, c, "Dropping outbound relay packets, tunnel message counter is exhausted")
+		return
+	}
 
 	out = header.Encode(out, header.Version, header.Message, header.MessageRelay, relay.RemoteIndex, c)
 	f.connectionManager.Out(via)
@@ -361,7 +376,14 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 		// NOTE: for goboring AESGCMTLS we need to lock because of the nonce check
 		ci.writeLock.Lock()
 	}
-	c := ci.messageCounter.Add(1)
+	c, ok := ci.NextMessageCounter()
+	if !ok {
+		if noiseutil.EncryptLockNeeded {
+			ci.writeLock.Unlock()
+		}
+		f.dropExhausted(hostinfo, c, "Dropping outbound packets, tunnel message counter is exhausted")
+		return
+	}
 
 	//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)

main.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/noiseutil"
 	"github.com/slackhq/nebula/overlay"
 	"github.com/slackhq/nebula/sshd"
 	"github.com/slackhq/nebula/udp"
@@ -20,6 +21,12 @@ import (
 
 type m = map[string]any
 
+// maxRoutines caps routines below the RejectHeadroom nonce gap so concurrent senders can't race the counter past wrap.
+const maxRoutines = 1 << 16
+
+// The reject headroom must exceed every sender that can be mid-reservation at once, about two per routine.
+const _ = noiseutil.RejectHeadroom - 4*maxRoutines
+
 func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, deviceFactory overlay.DeviceFactory) (retcon *Control, reterr error) {
 	ctx, cancel := context.WithCancel(context.Background())
 	// Automatically cancel the context if Main returns an error, to signal all created goroutines to quit.
@@ -81,9 +88,6 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 		if routines < 1 {
 			routines = 1
 		}
-		if routines > 1 {
-			l.Info("Using multiple routines", "routines", routines)
-		}
 	} else {
 		// deprecated and undocumented
 		tunQueues := c.GetInt("tun.routines", 1)
@@ -93,6 +97,12 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 			l.Warn("Setting tun.routines and listen.routines is deprecated. Use `routines` instead", "routines", routines)
 		}
 	}
+	if routines > maxRoutines {
+		l.Warn("Using multiple routines", "routines", maxRoutines, "clamped", true, "requestedRoutines", routines)
+		routines = maxRoutines
+	} else if routines > 1 {
+		l.Info("Using multiple routines", "routines", routines)
+	}
 
 	// EXPERIMENTAL
 	// Intentionally not documented yet while we do more testing and determine

message_metrics.go

@@ -14,7 +14,8 @@ type MessageMetrics struct {
 	rxUnknown metrics.Counter
 	txUnknown metrics.Counter
 
-	rxInvalid metrics.Counter
+	rxInvalid   metrics.Counter
+	txExhausted metrics.Counter
 }
 
 func (m *MessageMetrics) Rx(t header.MessageType, s header.MessageSubType, i int64) {
@@ -41,6 +42,13 @@ func (m *MessageMetrics) RxInvalid(i int64) {
 	}
 }
 
+// TxExhausted counts outbound packets dropped because the tunnel's message counter is spent.
+func (m *MessageMetrics) TxExhausted(i int64) {
+	if m != nil && m.txExhausted != nil {
+		m.txExhausted.Inc(i)
+	}
+}
+
 func newMessageMetrics() *MessageMetrics {
 	gen := func(t string) [][]metrics.Counter {
 		return [][]metrics.Counter{
@@ -61,9 +69,10 @@ func newMessageMetrics() *MessageMetrics {
 		rx: gen("rx"),
 		tx: gen("tx"),
 
-		rxUnknown: metrics.GetOrRegisterCounter("messages.rx.other", nil),
-		txUnknown: metrics.GetOrRegisterCounter("messages.tx.other", nil),
-		rxInvalid: metrics.GetOrRegisterCounter("messages.rx.invalid", nil),
+		rxUnknown:   metrics.GetOrRegisterCounter("messages.rx.other", nil),
+		txUnknown:   metrics.GetOrRegisterCounter("messages.tx.other", nil),
+		rxInvalid:   metrics.GetOrRegisterCounter("messages.rx.invalid", nil),
+		txExhausted: metrics.GetOrRegisterCounter("messages.tx.exhausted", nil),
 	}
 }
 

noiseutil/aesgcm.go

@@ -25,6 +25,9 @@ func (s *CipherStateAESGCM) EncryptDanger(out, ad, plaintext []byte, n uint64, n
 	if s == nil {
 		return nil, errors.New("no cipher state available to encrypt")
 	}
+	if n >= RejectAfterMessages {
+		return nil, ErrMessageCounterExhausted
+	}
 	nb[0] = 0
 	nb[1] = 0
 	nb[2] = 0

noiseutil/chachapoly.go

@@ -24,6 +24,9 @@ func (s *CipherStateChaChaPoly) EncryptDanger(out, ad, plaintext []byte, n uint6
 	if s == nil {
 		return nil, errors.New("no cipher state available to encrypt")
 	}
+	if n >= RejectAfterMessages {
+		return nil, ErrMessageCounterExhausted
+	}
 	nb[0] = 0
 	nb[1] = 0
 	nb[2] = 0

noiseutil/cipher_state.go

@@ -1,11 +1,22 @@
 package noiseutil
 
 import (
+	"errors"
 	"fmt"
+	"math"
 
 	"github.com/flynn/noise"
 )
 
+// RejectHeadroom is the wrap gap for senders racing the counter, sized large enough for any routine count.
+const RejectHeadroom = uint64(1) << 40
+
+// RejectAfterMessages is the nonce ceiling: encrypting stops RejectHeadroom short of the wrap.
+const RejectAfterMessages = math.MaxUint64 - RejectHeadroom
+
+// ErrMessageCounterExhausted is returned by EncryptDanger once the nonce reaches RejectAfterMessages.
+var ErrMessageCounterExhausted = errors.New("message counter exhausted")
+
 // CipherState is the post-handshake AEAD cipher used for the data plane.
 // Each supported cipher has its own concrete implementation in this package with the nonce endianness hardcoded,
 // so the encrypt/decrypt fast path avoids interface dispatch on the byte order.

noiseutil/cipher_state_test.go

@@ -1,6 +1,7 @@
 package noiseutil
 
 import (
+	"math"
 	"testing"
 
 	"github.com/flynn/noise"
@@ -89,6 +90,24 @@ func roundtrip(t *testing.T, enc, dec CipherState) {
 	assert.Equal(t, 16, enc.Overhead())
 }
 
+func TestEncryptRejectsExhaustedCounter(t *testing.T) {
+	// Pin the headroom below the uint64 wrap so a typo can't silently move the ceiling.
+	require.Equal(t, uint64(1)<<40, RejectHeadroom)
+	require.Equal(t, math.MaxUint64-RejectHeadroom, RejectAfterMessages)
+
+	encA, _ := buildCipherStates(t, CipherAESGCM)
+	encC, _ := buildCipherStates(t, noise.CipherChaChaPoly)
+	nb := make([]byte, 12)
+
+	for _, cs := range []CipherState{NewCipherStateAESGCM(encA), NewCipherStateChaChaPoly(encC)} {
+		_, err := cs.EncryptDanger(nil, nil, []byte("x"), RejectAfterMessages-1, nb)
+		require.NoError(t, err)
+
+		_, err = cs.EncryptDanger(nil, nil, []byte("x"), RejectAfterMessages, nb)
+		require.ErrorIs(t, err, ErrMessageCounterExhausted)
+	}
+}
+
 func BenchmarkCipherStateEncryptAESGCM(b *testing.B) {
 	enc, _ := buildCipherStatesB(b, CipherAESGCM)
 	benchEncryptCipherState(b, NewCipherState(enc, CipherAESGCM))

overlay/tun_linux.go

@@ -5,6 +5,7 @@ package overlay
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"io"
 	"log/slog"
@@ -483,7 +484,16 @@ func (t *tun) addIPs(link netlink.Link) error {
 	//iterate over remainder, remove whoever shouldn't be there
 	al, err := netlink.AddrList(link, netlink.FAMILY_ALL)
 	if err != nil {
-		return fmt.Errorf("failed to get tun address list: %s", err)
+		//RTM_GETADDR dumps the whole system, so any concurrent address change
+		//interrupts it - including the kernel's async tentative->preferred
+		//flip of an IPv6 address the AddrReplace calls above just added,
+		//which makes this a race against our own setup. Partial results are
+		//still returned; the worst case is a stale address surviving until
+		//the next config reload, which beats failing startup over it.
+		if !errors.Is(err, netlink.ErrDumpInterrupted) {
+			return fmt.Errorf("failed to get tun address list: %s", err)
+		}
+		t.l.Warn("tun address list dump was interrupted, stale addresses may remain")
 	}
 
 	for i := range al {

stats.go

@@ -13,7 +13,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	graphite "github.com/cyberdelia/go-metrics-graphite"
 	mp "github.com/nbrownus/go-metrics-prometheus"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -253,7 +252,7 @@ func (s *statsServer) buildRuntime(cfg statsConfig) ([]func(), *http.Server) {
 		// loadStatsConfig already resolved and validated the address; re-parse
 		// the resolved form (no DNS lookup) to get a *net.TCPAddr.
 		addr, _ := net.ResolveTCPAddr(cfg.graphite.protocol, cfg.graphite.resolvedAddr)
-		gcfg := graphite.Config{
+		gcfg := graphiteConfigExport{
 			Addr:          addr,
 			Registry:      metrics.DefaultRegistry,
 			FlushInterval: cfg.interval,
@@ -262,7 +261,7 @@ func (s *statsServer) buildRuntime(cfg statsConfig) ([]func(), *http.Server) {
 			Percentiles:   []float64{0.5, 0.75, 0.95, 0.99, 0.999},
 		}
 		captureFns = append(captureFns, func() {
-			if err := graphite.Once(gcfg); err != nil {
+			if err := graphiteOnce(gcfg); err != nil {
 				s.l.Error("Graphite export failed", "error", err)
 			}
 		})

stats_test.go

@@ -371,7 +371,7 @@ func waitForListening(t *testing.T, addr string) {
 	})
 }
 
-// graphiteSink is a minimal TCP accept-and-discard server so graphite.Once
+// graphiteSink is a minimal TCP accept-and-discard server so graphiteOnce
 // calls in tests don't spam error logs or wedge on connection refused.
 type graphiteSink struct {
 	ln net.Listener