fix

.github/workflows/gofmt.yml

@@ -0,0 +1,34 @@
+name: gofmt
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    paths:
+      - '.github/workflows/gofmt.yml'
+      - '**.go'
+jobs:
+
+  gofmt:
+    name: Run gofmt
+    runs-on: ubuntu-latest
+    steps:
+
+    - uses: actions/checkout@v6
+
+    - uses: actions/setup-go@v6
+      with:
+        go-version: '1.25'
+        check-latest: true
+
+    - name: Install goimports
+      run: |
+        go install golang.org/x/tools/cmd/goimports@latest
+
+    - name: gofmt
+      run: |
+        if [ "$(find . -iname '*.go' | grep -v '\.pb\.go$' | xargs goimports -l)" ]
+        then
+          find . -iname '*.go' | grep -v '\.pb\.go$' | xargs goimports -d
+          exit 1
+        fi

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     name: Build Linux/BSD All
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-go@v6
         with:
@@ -36,7 +36,7 @@ jobs:
       id-token: write
       contents: read
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-go@v6
         with:
@@ -76,7 +76,7 @@ jobs:
       HAS_SIGNING_CREDS: ${{ secrets.AC_USERNAME != '' }}
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-go@v6
         with:
@@ -134,7 +134,7 @@ jobs:
       # be overwritten
       - name: Checkout code
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: actions/checkout@v7
+        uses: actions/checkout@v6
 
       - name: Download artifacts
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
@@ -163,17 +163,14 @@ jobs:
           mkdir -p build/linux-{amd64,arm64}
           tar -zxvf artifacts/nebula-linux-amd64.tar.gz -C build/linux-amd64/
           tar -zxvf artifacts/nebula-linux-arm64.tar.gz -C build/linux-arm64/
-          docker buildx build . --push -f docker/Dockerfile --platform linux/amd64,linux/arm64 \
-            --build-arg VERSION="${GITHUB_REF#refs/tags/v}" \
-            --build-arg REVISION="${GITHUB_SHA}" \
-            --tag "${DOCKER_IMAGE_REPO}:${DOCKER_IMAGE_TAG}" --tag "${DOCKER_IMAGE_REPO}:${GITHUB_REF#refs/tags/v}"
+          docker buildx build . --push -f docker/Dockerfile --platform linux/amd64,linux/arm64 --tag "${DOCKER_IMAGE_REPO}:${DOCKER_IMAGE_TAG}" --tag "${DOCKER_IMAGE_REPO}:${GITHUB_REF#refs/tags/v}"
 
   release:
     name: Create and Upload Release
     needs: [build-linux, build-darwin, build-windows]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
 
       - name: Download artifacts
         uses: actions/download-artifact@v8

.github/workflows/smoke-extra.yml

@@ -30,7 +30,7 @@ jobs:
       VAGRANT_DEFAULT_PROVIDER: libvirt
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
@@ -62,7 +62,7 @@ jobs:
       VAGRANT_DEFAULT_PROVIDER: virtualbox
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
@@ -88,7 +88,7 @@ jobs:
     runs-on: windows-latest
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
@@ -98,7 +98,7 @@ jobs:
     # WSL2 + Ubuntu so the smoke can run a real linux peer with its own
     # netns. iputils-ping is needed for the in-WSL ping check. WSL1 has no
     # real kernel and would lack /dev/net/tun, so we have to force WSL2.
-    - uses: Vampire/setup-wsl@v7
+    - uses: Vampire/setup-wsl@v3
       with:
         distribution: Ubuntu-24.04
         additional-packages: iputils-ping iproute2

.github/workflows/smoke.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
@@ -36,14 +36,6 @@ jobs:
       working-directory: ./.github/workflows/smoke
       run: ./smoke.sh
 
-    - name: setup docker image ipv6
-      working-directory: ./.github/workflows/smoke
-      run: SMOKE_OVERLAY_IPV6=1 ./build.sh
-
-    - name: run smoke ipv6
-      working-directory: ./.github/workflows/smoke
-      run: SMOKE_OVERLAY_IPV6=1 ./smoke.sh
-
     - name: setup relay docker image
       working-directory: ./.github/workflows/smoke
       run: ./build-relay.sh

.github/workflows/smoke/build.sh

@@ -5,19 +5,6 @@ set -e -x
 rm -rf ./build
 mkdir ./build
 
-if [ "$SMOKE_OVERLAY_IPV6" ]
-then
-    LIGHTHOUSE_NIP="fd00:4242:0:0:0:ffff:c0a8:6401"
-    HOST2_NIP="fd00:4242:0:0:0:ffff:c0a8:6402"
-    HOST3_NIP="fd00:4242:0:0:0:ffff:c0a8:6403"
-    HOST4_NIP="fd00:4242:0:0:0:ffff:c0a8:6404"
-else
-    LIGHTHOUSE_NIP="192.168.100.1"
-    HOST2_NIP="192.168.100.2"
-    HOST3_NIP="192.168.100.3"
-    HOST4_NIP="192.168.100.4"
-fi
-
 # Smoke containers run on a dedicated docker network whose subnet is allocated
 # at smoke time, not known at build time. Configs are written with TEST-NET-3
 # placeholder IPs (RFC 5737) and smoke.sh / smoke-vagrant.sh / smoke-relay.sh
@@ -44,24 +31,24 @@ LIGHTHOUSE_IP="203.0.113.2"
         ../genconfig.sh >lighthouse1.yml
 
     HOST="host2" \
-        LIGHTHOUSES="$LIGHTHOUSE_NIP $LIGHTHOUSE_IP:4242" \
+        LIGHTHOUSES="192.168.100.1 $LIGHTHOUSE_IP:4242" \
         ../genconfig.sh >host2.yml
 
     HOST="host3" \
-        LIGHTHOUSES="$LIGHTHOUSE_NIP $LIGHTHOUSE_IP:4242" \
+        LIGHTHOUSES="192.168.100.1 $LIGHTHOUSE_IP:4242" \
         INBOUND='[{"port": "any", "proto": "icmp", "group": "lighthouse"}]' \
         ../genconfig.sh >host3.yml
 
     HOST="host4" \
-        LIGHTHOUSES="$LIGHTHOUSE_NIP $LIGHTHOUSE_IP:4242" \
+        LIGHTHOUSES="192.168.100.1 $LIGHTHOUSE_IP:4242" \
         OUTBOUND='[{"port": "any", "proto": "icmp", "group": "lighthouse"}]' \
         ../genconfig.sh >host4.yml
 
     ../../../../nebula-cert ca -curve "${CURVE:-25519}" -name "Smoke Test"
-    ../../../../nebula-cert sign -name "lighthouse1" -groups "lighthouse,lighthouse1" -ip "$LIGHTHOUSE_NIP/24"
-    ../../../../nebula-cert sign -name "host2" -groups "host,host2" -ip "$HOST2_NIP/24"
-    ../../../../nebula-cert sign -name "host3" -groups "host,host3" -ip "$HOST3_NIP/24"
-    ../../../../nebula-cert sign -name "host4" -groups "host,host4" -ip "$HOST4_NIP/24"
+    ../../../../nebula-cert sign -name "lighthouse1" -groups "lighthouse,lighthouse1" -ip "192.168.100.1/24"
+    ../../../../nebula-cert sign -name "host2" -groups "host,host2" -ip "192.168.100.2/24"
+    ../../../../nebula-cert sign -name "host3" -groups "host,host3" -ip "192.168.100.3/24"
+    ../../../../nebula-cert sign -name "host4" -groups "host,host4" -ip "192.168.100.4/24"
 )
 
 docker build -t "nebula:${NAME:-smoke}" .

.github/workflows/smoke/smoke.sh

@@ -47,19 +47,6 @@ HOST2_IP="$PREFIX.3"
 HOST3_IP="$PREFIX.4"
 HOST4_IP="$PREFIX.5"
 
-if [ "$SMOKE_OVERLAY_IPV6" ]
-then
-    LIGHTHOUSE_NIP="fd00:4242:0:0:0:ffff:c0a8:6401"
-    HOST2_NIP="fd00:4242:0:0:0:ffff:c0a8:6402"
-    HOST3_NIP="fd00:4242:0:0:0:ffff:c0a8:6403"
-    HOST4_NIP="fd00:4242:0:0:0:ffff:c0a8:6404"
-else
-    LIGHTHOUSE_NIP="192.168.100.1"
-    HOST2_NIP="192.168.100.2"
-    HOST3_NIP="192.168.100.3"
-    HOST4_NIP="192.168.100.4"
-fi
-
 # Sed the placeholder TEST-NET-3 IPs in the host configs to the real ones.
 # build/lighthouse1.yml has no IPs to rewrite so it's skipped.
 for f in build/host2.yml build/host3.yml build/host4.yml; do
@@ -93,28 +80,28 @@ docker exec host3 tcpdump -i eth0 -q -w - -U 2>logs/host3.outside.log >logs/host
 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 2000 &
-docker exec host3 ncat -nklv 2000 &
-docker exec host4 ncat -e '/usr/bin/echo helloagainfromhost4' -nkluv 4000 &
-docker exec host2 ncat -e '/usr/bin/echo host2' -nkluv 3000 &
-docker exec host3 ncat -e '/usr/bin/echo host3' -nkluv 3000 &
+docker exec host2 ncat -nklv 0.0.0.0 2000 &
+docker exec host3 ncat -nklv 0.0.0.0 2000 &
+docker exec host4 ncat -e '/usr/bin/echo helloagainfromhost4' -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 &
 
 set +x
 echo
 echo " *** Testing ping from lighthouse1"
 echo
 set -x
-docker exec lighthouse1 ping -c1 $HOST2_NIP
-docker exec lighthouse1 ping -c1 $HOST3_NIP
+docker exec lighthouse1 ping -c1 192.168.100.2
+docker exec lighthouse1 ping -c1 192.168.100.3
 
 set +x
 echo
 echo " *** Testing ping from host2"
 echo
 set -x
-docker exec host2 ping -c1 $LIGHTHOUSE_NIP
+docker exec host2 ping -c1 192.168.100.1
 # Should fail because not allowed by host3 inbound firewall
-! docker exec host2 ping -c1 $HOST3_NIP -w5 || exit 1
+! docker exec host2 ping -c1 192.168.100.3 -w5 || exit 1
 
 set +x
 echo
@@ -122,34 +109,34 @@ echo " *** Testing ncat from host2"
 echo
 set -x
 # Should fail because not allowed by host3 inbound firewall
-! docker exec host2 ncat -nzv -w5 $HOST3_NIP 2000 || exit 1
-! docker exec host2 ncat -nzuv -w5 $HOST3_NIP 3000 | grep -q host3 || exit 1
+! docker exec host2 ncat -nzv -w5 192.168.100.3 2000 || exit 1
+! docker exec host2 ncat -nzuv -w5 192.168.100.3 3000 | grep -q host3 || exit 1
 
 set +x
 echo
 echo " *** Testing ping from host3"
 echo
 set -x
-docker exec host3 ping -c1 $LIGHTHOUSE_NIP
-docker exec host3 ping -c1 $HOST2_NIP
+docker exec host3 ping -c1 192.168.100.1
+docker exec host3 ping -c1 192.168.100.2
 
 set +x
 echo
 echo " *** Testing ncat from host3"
 echo
 set -x
-docker exec host3 ncat -nzv -w5 $HOST2_NIP 2000
-docker exec host3 ncat -nzuv -w5 $HOST2_NIP 3000 | grep -q host2
+docker exec host3 ncat -nzv -w5 192.168.100.2 2000
+docker exec host3 ncat -nzuv -w5 192.168.100.2 3000 | grep -q host2
 
 set +x
 echo
 echo " *** Testing ping from host4"
 echo
 set -x
-docker exec host4 ping -c1 $LIGHTHOUSE_NIP
+docker exec host4 ping -c1 192.168.100.1
 # Should fail because not allowed by host4 outbound firewall
-! docker exec host4 ping -c1 $HOST2_NIP -w5 || exit 1
-! docker exec host4 ping -c1 $HOST3_NIP -w5 || exit 1
+! docker exec host4 ping -c1 192.168.100.2 -w5 || exit 1
+! docker exec host4 ping -c1 192.168.100.3 -w5 || exit 1
 
 set +x
 echo
@@ -157,10 +144,10 @@ echo " *** Testing ncat from host4"
 echo
 set -x
 # Should fail because not allowed by host4 outbound firewall
-! docker exec host4 ncat -nzv -w5 $HOST2_NIP 2000 || exit 1
-! docker exec host4 ncat -nzv -w5 $HOST3_NIP 2000 || exit 1
-! docker exec host4 ncat -nzuv -w5 $HOST2_NIP 3000 | grep -q host2 || exit 1
-! docker exec host4 ncat -nzuv -w5 $HOST3_NIP 3000 | grep -q host3 || exit 1
+! docker exec host4 ncat -nzv -w5 192.168.100.2 2000 || exit 1
+! docker exec host4 ncat -nzv -w5 192.168.100.3 2000 || exit 1
+! docker exec host4 ncat -nzuv -w5 192.168.100.2 3000 | grep -q host2 || exit 1
+! docker exec host4 ncat -nzuv -w5 192.168.100.3 3000 | grep -q host3 || exit 1
 
 set +x
 echo
@@ -172,7 +159,7 @@ set -x
 # cannot initiate UDP to host2. Once host2 initiates a flow to host4:4000,
 # conntrack must let host4's listener reply on that flow. If it doesn't,
 # the echo back from host4 never reaches host2.
-docker exec host2 sh -c "(/usr/bin/echo host2; sleep 2) | ncat -nuv $HOST4_NIP 4000" | grep -q helloagainfromhost4
+docker exec host2 sh -c "(/usr/bin/echo host2; sleep 2) | ncat -nuv 192.168.100.4 4000" | grep -q helloagainfromhost4
 
 docker exec host4 sh -c 'kill 1'
 docker exec host3 sh -c 'kill 1'

.github/workflows/test.yml

@@ -13,28 +13,20 @@ on:
       - 'go.sum'
 jobs:
 
-  static:
-    name: Static checks
+  test-linux:
+    name: Build all and test on ubuntu-linux
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
         go-version: '1.25'
         check-latest: true
 
-    - name: Install goimports
-      run: go install golang.org/x/tools/cmd/goimports@latest
-
-    - name: gofmt
-      run: |
-        if [ "$(find . -iname '*.go' | grep -v '\.pb\.go$' | xargs goimports -l)" ]
-        then
-          find . -iname '*.go' | grep -v '\.pb\.go$' | xargs goimports -d
-          exit 1
-        fi
+    - name: Build
+      run: make all
 
     - name: Vet
       run: make vet
@@ -44,41 +36,27 @@ jobs:
       with:
         version: v2.5
 
-  test:
-    name: Test ${{ matrix.name }}
-    runs-on: ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        - name: linux
-          os: ubuntu-latest
-          build-cmd: go build ./cmd/nebula ./cmd/nebula-cert
-          test-cmd: make test
-          e2e-cmd: make e2evv
-        - name: linux-boringcrypto
-          os: ubuntu-latest
-          build-cmd: make bin-boringcrypto
-          test-cmd: make test-boringcrypto
-          e2e-cmd: make e2e GOEXPERIMENT=boringcrypto CGO_ENABLED=1 TEST_ENV="TEST_LOGS=1" TEST_FLAGS="-v -ldflags -checklinkname=0"
-        - name: linux-pkcs11
-          os: ubuntu-latest
-          build-cmd: make bin-pkcs11
-          test-cmd: make test-pkcs11
-          e2e-cmd: ''
-        - name: macos
-          os: macos-latest
-          build-cmd: go build ./cmd/nebula ./cmd/nebula-cert
-          test-cmd: make test
-          e2e-cmd: make e2evv
-        - name: windows
-          os: windows-latest
-          build-cmd: go build ./cmd/nebula ./cmd/nebula-cert
-          test-cmd: make test
-          e2e-cmd: make e2evv
+    - name: Test
+      run: make test
+
+    - name: End 2 end
+      run: make e2evv
+
+    - name: Build test mobile
+      run: make build-test-mobile
+
+    - uses: actions/upload-artifact@v7
+      with:
+        name: e2e packet flow linux-latest
+        path: e2e/mermaid/linux-latest
+        if-no-files-found: warn
+
+  test-linux-boringcrypto:
+    name: Build and test on linux with boringcrypto
+    runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
@@ -86,65 +64,69 @@ jobs:
         check-latest: true
 
     - name: Build
-      run: ${{ matrix.build-cmd }}
-
-    - name: Cross-build darwin-amd64
-      if: matrix.name == 'macos'
-      run: GOARCH=amd64 go build -o /tmp/nebula-amd64 ./cmd/nebula && GOARCH=amd64 go build -o /tmp/nebula-cert-amd64 ./cmd/nebula-cert
+      run: make bin-boringcrypto
 
     - name: Test
-      run: ${{ matrix.test-cmd }}
+      run: make test-boringcrypto
 
     - name: End 2 end
-      if: matrix.e2e-cmd != ''
-      run: ${{ matrix.e2e-cmd }}
+      run: make e2e GOEXPERIMENT=boringcrypto CGO_ENABLED=1 TEST_ENV="TEST_LOGS=1" TEST_FLAGS="-v -ldflags -checklinkname=0"
 
-    - uses: actions/upload-artifact@v7
-      if: matrix.e2e-cmd != '' && always()
-      with:
-        name: e2e packet flow ${{ matrix.name }}
-        path: e2e/mermaid/
-        if-no-files-found: warn
-
-  cross-build:
-    name: Cross-build ${{ matrix.name }}
+  test-linux-pkcs11:
+    name: Build and test on linux with pkcs11
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-        - {name: linux-arm,   make-target: all-cross-linux-arm}
-        - {name: linux-mips,  make-target: all-cross-linux-mips}
-        - {name: linux-other, make-target: all-cross-linux-other}
-        - {name: freebsd,     make-target: all-freebsd}
-        - {name: openbsd,     make-target: all-openbsd}
-        - {name: netbsd,      make-target: all-netbsd}
-        - {name: windows,     make-target: all-cross-windows}
-        - {name: mobile,      make-target: build-test-mobile}
     steps:
 
-    - uses: actions/checkout@v7
+    - uses: actions/checkout@v6
 
     - uses: actions/setup-go@v6
       with:
         go-version: '1.25'
         check-latest: true
 
-    - name: Build ${{ matrix.name }}
-      run: make -j"$(nproc)" ${{ matrix.make-target }}
+    - name: Build
+      run: make bin-pkcs11
 
-  finish:
-    name: CI status
-    if: always()
-    needs: [static, test, cross-build]
-    runs-on: ubuntu-latest
+    - name: Test
+      run: make test-pkcs11
+
+  test:
+    name: Build and test on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [windows-latest, macos-latest]
     steps:
 
-    - name: Fail if any upstream job failed
-      if: contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled')
-      run: |
-        echo "upstream results: ${{ toJSON(needs) }}"
-        exit 1
+    - uses: actions/checkout@v6
 
-    - name: All upstream jobs passed
-      run: echo "ok"
+    - uses: actions/setup-go@v6
+      with:
+        go-version: '1.25'
+        check-latest: true
+
+    - name: Build nebula
+      run: go build ./cmd/nebula
+
+    - name: Build nebula-cert
+      run: go build ./cmd/nebula-cert
+
+    - name: Vet
+      run: make vet
+
+    - name: golangci-lint
+      uses: golangci/golangci-lint-action@v9
+      with:
+        version: v2.5
+
+    - name: Test
+      run: make test
+
+    - name: End 2 end
+      run: make e2evv
+
+    - uses: actions/upload-artifact@v7
+      with:
+        name: e2e packet flow ${{ matrix.os }}
+        path: e2e/mermaid/${{ matrix.os }}
+        if-no-files-found: warn

Makefile

@@ -60,18 +60,6 @@ ALL = $(ALL_LINUX) \
 	windows-amd64 \
 	windows-arm64
 
-# Cross-build shards used by .github/workflows/test.yml — same as ALL_*
-# but with the arch that has a native CI runner removed, so the cross-build
-# job is not duplicating coverage the native test jobs already give.
-ALL_CROSS_LINUX = $(filter-out linux-amd64,$(ALL_LINUX))
-
-# ALL_CROSS_LINUX further split into family sub-shards so each can run on
-# its own CI runner in parallel. Union of the three must equal
-# ALL_CROSS_LINUX; adding a new linux arch goes into the matching family.
-ALL_CROSS_LINUX_ARM   = linux-arm-5 linux-arm-6 linux-arm-7 linux-arm64
-ALL_CROSS_LINUX_MIPS  = linux-mips linux-mipsle linux-mips64 linux-mips64le linux-mips-softfloat
-ALL_CROSS_LINUX_OTHER = linux-386 linux-ppc64le linux-riscv64 linux-loong64
-
 e2e:
 	$(TEST_ENV) go test -tags=e2e_testing -count=1 $(TEST_FLAGS) ./e2e
 
@@ -94,35 +82,6 @@ DOCKER_BIN = build/linux-amd64/nebula build/linux-amd64/nebula-cert
 
 all: $(ALL:%=build/%/nebula) $(ALL:%=build/%/nebula-cert)
 
-all-linux: $(ALL_LINUX:%=build/%/nebula) $(ALL_LINUX:%=build/%/nebula-cert)
-
-all-freebsd: $(ALL_FREEBSD:%=build/%/nebula) $(ALL_FREEBSD:%=build/%/nebula-cert)
-
-all-openbsd: $(ALL_OPENBSD:%=build/%/nebula) $(ALL_OPENBSD:%=build/%/nebula-cert)
-
-all-netbsd: $(ALL_NETBSD:%=build/%/nebula) $(ALL_NETBSD:%=build/%/nebula-cert)
-
-all-darwin: build/darwin-amd64/nebula build/darwin-amd64/nebula-cert build/darwin-arm64/nebula build/darwin-arm64/nebula-cert
-
-all-windows: build/windows-amd64/nebula.exe build/windows-amd64/nebula-cert.exe build/windows-arm64/nebula.exe build/windows-arm64/nebula-cert.exe
-
-# CI cross-build shards. darwin-arm64 is covered by the native macos-latest
-# job; windows-amd64 is covered by the native windows-latest job; both are
-# omitted here to avoid building them a second time. darwin-amd64 stays in
-# all-cross-darwin because intel mac is only a labeled/master-time native
-# job, so PRs still need cross-build coverage for it.
-all-cross-linux: $(ALL_CROSS_LINUX:%=build/%/nebula) $(ALL_CROSS_LINUX:%=build/%/nebula-cert)
-
-all-cross-linux-arm:   $(ALL_CROSS_LINUX_ARM:%=build/%/nebula)   $(ALL_CROSS_LINUX_ARM:%=build/%/nebula-cert)
-
-all-cross-linux-mips:  $(ALL_CROSS_LINUX_MIPS:%=build/%/nebula)  $(ALL_CROSS_LINUX_MIPS:%=build/%/nebula-cert)
-
-all-cross-linux-other: $(ALL_CROSS_LINUX_OTHER:%=build/%/nebula) $(ALL_CROSS_LINUX_OTHER:%=build/%/nebula-cert)
-
-all-cross-darwin: build/darwin-amd64/nebula build/darwin-amd64/nebula-cert
-
-all-cross-windows: build/windows-arm64/nebula.exe build/windows-arm64/nebula-cert.exe
-
 docker: docker/linux-$(shell go env GOARCH)
 
 release: $(ALL:%=build/nebula-%.tar.gz)
@@ -268,9 +227,6 @@ smoke-relay-docker: bin-docker
 	cd .github/workflows/smoke/ && ./build-relay.sh
 	cd .github/workflows/smoke/ && ./smoke-relay.sh
 
-smoke-docker-ipv6: export SMOKE_OVERLAY_IPV6 = 1
-smoke-docker-ipv6: smoke-docker
-
 smoke-docker-race: BUILD_ARGS = -race
 smoke-docker-race: CGO_ENABLED = 1
 smoke-docker-race: smoke-docker
@@ -280,5 +236,5 @@ smoke-vagrant/%: bin-docker build/%/nebula
 	cd .github/workflows/smoke/ && ./smoke-vagrant.sh $*
 
 .FORCE:
-.PHONY: all all-linux all-freebsd all-openbsd all-netbsd all-darwin all-windows all-cross-linux all-cross-linux-arm all-cross-linux-mips all-cross-linux-other all-cross-darwin all-cross-windows bench bench-cpu bench-cpu-long bin build-test-mobile e2e e2ev e2evv e2evvv e2evvvv proto release service smoke-docker smoke-docker-race test test-cov-html smoke-vagrant/%
+.PHONY: bench bench-cpu bench-cpu-long bin build-test-mobile e2e e2ev e2evv e2evvv e2evvvv proto release service smoke-docker smoke-docker-race test test-cov-html smoke-vagrant/%
 .DEFAULT_GOAL := bin

cert/helper_test.go

@@ -13,12 +13,6 @@ import (
 	"golang.org/x/crypto/ed25519"
 )
 
-// testCertNow is the reference "now" used to derive default before/after times
-// in NewTestCaCert and NewTestCert. Holding it fixed for the lifetime of the
-// test binary keeps CA and leaf defaults aligned at the same second, so a leaf
-// signed with default times can never expire after its CA on a rounding race.
-var testCertNow = time.Now().Round(time.Second)
-
 // NewTestCaCert will create a new ca certificate
 func NewTestCaCert(version Version, curve Curve, before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (Certificate, []byte, []byte, []byte) {
 	var err error
@@ -40,10 +34,10 @@ func NewTestCaCert(version Version, curve Curve, before, after time.Time, networ
 	}
 
 	if before.IsZero() {
-		before = testCertNow.Add(time.Second * -60)
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
 	}
 	if after.IsZero() {
-		after = testCertNow.Add(time.Second * 60)
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
 	}
 
 	t := &TBSCertificate{
@@ -76,11 +70,11 @@ func NewTestCaCert(version Version, curve Curve, before, after time.Time, networ
 // Expiry times are defaulted if you do not pass them in
 func NewTestCert(v Version, curve Curve, ca Certificate, key []byte, name string, before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (Certificate, []byte, []byte, []byte) {
 	if before.IsZero() {
-		before = testCertNow.Add(time.Second * -60)
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
 	}
 
 	if after.IsZero() {
-		after = testCertNow.Add(time.Second * 60)
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
 	}
 
 	if len(networks) == 0 {

cert_test/cert.go

@@ -14,12 +14,6 @@ import (
 	"golang.org/x/crypto/ed25519"
 )
 
-// testCertNow is the reference "now" used to derive default before/after times
-// in NewTestCaCert and NewTestCert. Holding it fixed for the lifetime of the
-// test binary keeps CA and leaf defaults aligned at the same second, so a leaf
-// signed with default times can never expire after its CA on a rounding race.
-var testCertNow = time.Now().Round(time.Second)
-
 // NewTestCaCert will create a new ca certificate
 func NewTestCaCert(version cert.Version, curve cert.Curve, before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (cert.Certificate, []byte, []byte, []byte) {
 	var err error
@@ -41,10 +35,10 @@ func NewTestCaCert(version cert.Version, curve cert.Curve, before, after time.Ti
 	}
 
 	if before.IsZero() {
-		before = testCertNow.Add(time.Second * -60)
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
 	}
 	if after.IsZero() {
-		after = testCertNow.Add(time.Second * 60)
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
 	}
 
 	t := &cert.TBSCertificate{
@@ -77,11 +71,11 @@ func NewTestCaCert(version cert.Version, curve cert.Curve, before, after time.Ti
 // Expiry times are defaulted if you do not pass them in
 func NewTestCert(v cert.Version, curve cert.Curve, ca cert.Certificate, key []byte, name string, before, after time.Time, networks, unsafeNetworks []netip.Prefix, groups []string) (cert.Certificate, []byte, []byte, []byte) {
 	if before.IsZero() {
-		before = testCertNow.Add(time.Second * -60)
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
 	}
 
 	if after.IsZero() {
-		after = testCertNow.Add(time.Second * 60)
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
 	}
 
 	var pub, priv []byte

cmd/nebula-cert/ca.go

@@ -97,19 +97,6 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 		if err = mustFlagString("out-key", cf.outKeyPath); err != nil {
 			return err
 		}
-	} else {
-		// out-key is meaningless under PKCS#11 because the private key never
-		// leaves the HSM; reject it so we never silently accept or claim a
-		// stdout slot for it.
-		outKeySet := false
-		cf.set.Visit(func(f *flag.Flag) {
-			if f.Name == "out-key" {
-				outKeySet = true
-			}
-		})
-		if outKeySet {
-			return newHelpErrorf("cannot set -out-key with -pkcs11")
-		}
 	}
 	if err := mustFlagString("out-crt", cf.outCertPath); err != nil {
 		return err
@@ -184,21 +171,12 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 		}
 	}
 
-	var claims ioClaims
-	if err := reserveOutputs(&claims,
-		"out-key", *cf.outKeyPath,
-		"out-crt", *cf.outCertPath,
-		"out-qr", *cf.outQRPath,
-	); err != nil {
-		return err
-	}
-
 	var passphrase []byte
 	if !isP11 && *cf.encryption {
 		passphrase = []byte(os.Getenv("NEBULA_CA_PASSPHRASE"))
 		if len(passphrase) == 0 {
 			for i := 0; i < 5; i++ {
-				errOut.Write([]byte("Enter passphrase: "))
+				out.Write([]byte("Enter passphrase: "))
 				passphrase, err = pr.ReadPassword()
 
 				if err == ErrNoTerminal {
@@ -283,16 +261,14 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 		Curve:          curve,
 	}
 
-	if !isP11 && !isStdio(*cf.outKeyPath) {
+	if !isP11 {
 		if _, err := os.Stat(*cf.outKeyPath); err == nil {
 			return fmt.Errorf("refusing to overwrite existing CA key: %s", *cf.outKeyPath)
 		}
 	}
 
-	if !isStdio(*cf.outCertPath) {
-		if _, err := os.Stat(*cf.outCertPath); err == nil {
-			return fmt.Errorf("refusing to overwrite existing CA cert: %s", *cf.outCertPath)
-		}
+	if _, err := os.Stat(*cf.outCertPath); err == nil {
+		return fmt.Errorf("refusing to overwrite existing CA cert: %s", *cf.outCertPath)
 	}
 
 	var c cert.Certificate
@@ -318,7 +294,7 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 			b = cert.MarshalSigningPrivateKeyToPEM(curve, rawPriv)
 		}
 
-		err = writeOutput(*cf.outKeyPath, b, 0600, out)
+		err = os.WriteFile(*cf.outKeyPath, b, 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-key: %s", err)
 		}
@@ -329,7 +305,7 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 		return fmt.Errorf("error while marshalling certificate: %s", err)
 	}
 
-	err = writeOutput(*cf.outCertPath, b, 0600, out)
+	err = os.WriteFile(*cf.outCertPath, b, 0600)
 	if err != nil {
 		return fmt.Errorf("error while writing out-crt: %s", err)
 	}
@@ -340,7 +316,7 @@ func ca(args []string, out io.Writer, errOut io.Writer, pr PasswordReader) error
 			return fmt.Errorf("error while generating qr code: %s", err)
 		}
 
-		err = writeOutput(*cf.outQRPath, b, 0600, out)
+		err = os.WriteFile(*cf.outQRPath, b, 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-qr: %s", err)
 		}
@@ -356,7 +332,6 @@ func caSummary() string {
 func caHelp(out io.Writer) {
 	cf := newCaFlags()
 	out.Write([]byte("Usage of " + os.Args[0] + " " + caSummary() + "\n"))
-	out.Write([]byte(stdioHelpText))
 	cf.set.SetOutput(out)
 	cf.set.PrintDefaults()
 }

cmd/nebula-cert/ca_test.go

@@ -27,7 +27,6 @@ func Test_caHelp(t *testing.T) {
 	assert.Equal(
 		t,
 		"Usage of "+os.Args[0]+" ca <flags>: create a self signed certificate authority\n"+
-			"  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"+
 			"  -argon-iterations uint\n"+
 			"    \tOptional: Argon2 iterations parameter used for encrypted private key passphrase (default 1)\n"+
 			"  -argon-memory uint\n"+
@@ -85,7 +84,7 @@ func Test_ca(t *testing.T) {
 		err:      nil,
 	}
 
-	pwPromptEB := "Enter passphrase: "
+	pwPromptOb := "Enter passphrase: "
 
 	// required args
 	assertHelpError(t, ca(
@@ -169,8 +168,8 @@ func Test_ca(t *testing.T) {
 	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()}
 	require.NoError(t, ca(args, ob, eb, testpw))
-	assert.Empty(t, ob.String())
-	assert.Equal(t, pwPromptEB, eb.String())
+	assert.Equal(t, pwPromptOb, ob.String())
+	assert.Empty(t, eb.String())
 
 	// test encrypted key with passphrase environment variable
 	os.Remove(keyF.Name())
@@ -208,8 +207,8 @@ func Test_ca(t *testing.T) {
 	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()}
 	require.Error(t, ca(args, ob, eb, errpw))
-	assert.Empty(t, ob.String())
-	assert.Equal(t, pwPromptEB, eb.String())
+	assert.Equal(t, pwPromptOb, ob.String())
+	assert.Empty(t, eb.String())
 
 	// test when user fails to enter a password
 	os.Remove(keyF.Name())
@@ -218,8 +217,8 @@ func Test_ca(t *testing.T) {
 	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()}
 	require.EqualError(t, ca(args, ob, eb, nopw), "no passphrase specified, remove -encrypt flag to write out-key in plaintext")
-	assert.Empty(t, ob.String())
-	assert.Equal(t, strings.Repeat(pwPromptEB, 5), eb.String()) // prompts 5 times before giving up
+	assert.Equal(t, strings.Repeat(pwPromptOb, 5), ob.String()) // prompts 5 times before giving up
+	assert.Empty(t, eb.String())
 
 	// create valid cert/key for overwrite tests
 	os.Remove(keyF.Name())
@@ -248,67 +247,3 @@ func Test_ca(t *testing.T) {
 	os.Remove(keyF.Name())
 
 }
-
-func Test_ca_stdio(t *testing.T) {
-	nopw := &StubPasswordReader{}
-
-	keyF, err := os.CreateTemp("", "ca.key")
-	require.NoError(t, err)
-	os.Remove(keyF.Name())
-	defer os.Remove(keyF.Name())
-
-	crtF, err := os.CreateTemp("", "ca.crt")
-	require.NoError(t, err)
-	os.Remove(crtF.Name())
-	defer os.Remove(crtF.Name())
-
-	// out-crt on stdout, out-key on disk
-	ob := &bytes.Buffer{}
-	eb := &bytes.Buffer{}
-	require.NoError(t, ca([]string{"-name", "test-ca", "-duration", "1h", "-out-crt", "-", "-out-key", keyF.Name()}, ob, eb, nopw))
-	assert.Empty(t, eb.String())
-	c, _, err := cert.UnmarshalCertificateFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.True(t, c.IsCA())
-	assert.Equal(t, "test-ca", c.Name())
-
-	// out-key on stdout, out-crt on disk
-	os.Remove(keyF.Name())
-	ob.Reset()
-	eb.Reset()
-	require.NoError(t, ca([]string{"-name", "test-ca", "-duration", "1h", "-out-crt", crtF.Name(), "-out-key", "-"}, ob, eb, nopw))
-	assert.Empty(t, eb.String())
-	_, _, curve, err := cert.UnmarshalSigningPrivateKeyFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, cert.Curve_CURVE25519, curve)
-
-	// dual stdout is rejected up front
-	os.Remove(crtF.Name())
-	ob.Reset()
-	eb.Reset()
-	require.EqualError(t,
-		ca([]string{"-name", "test-ca", "-duration", "1h", "-out-crt", "-", "-out-key", "-"}, ob, eb, nopw),
-		`-out-key and -out-crt both set to "-", only one output may write to stdout`)
-	assert.Empty(t, ob.String())
-
-	// an output conflict combined with -encrypt must error BEFORE prompting
-	// for a passphrase; pr would record any read attempt
-	tracker := &trackingPasswordReader{}
-	ob.Reset()
-	eb.Reset()
-	require.EqualError(t,
-		ca([]string{"-name", "test-ca", "-duration", "1h", "-encrypt", "-out-crt", "-", "-out-key", "-"}, ob, eb, tracker),
-		`-out-key and -out-crt both set to "-", only one output may write to stdout`)
-	assert.Empty(t, ob.String())
-	assert.Empty(t, eb.String())
-	assert.Zero(t, tracker.calls, "passphrase prompt should not have been called")
-}
-
-type trackingPasswordReader struct {
-	calls int
-}
-
-func (pr *trackingPasswordReader) ReadPassword() ([]byte, error) {
-	pr.calls++
-	return []byte(""), nil
-}

cmd/nebula-cert/keygen.go

@@ -42,8 +42,6 @@ func keygen(args []string, out io.Writer, errOut io.Writer) error {
 		if err = mustFlagString("out-key", cf.outKeyPath); err != nil {
 			return err
 		}
-	} else if *cf.outKeyPath != "" {
-		return newHelpErrorf("cannot set -out-key with -pkcs11")
 	}
 	if err = mustFlagString("out-pub", cf.outPubPath); err != nil {
 		return err
@@ -71,14 +69,6 @@ func keygen(args []string, out io.Writer, errOut io.Writer) error {
 		}
 	}
 
-	var claims ioClaims
-	if err := reserveOutputs(&claims,
-		"out-key", *cf.outKeyPath,
-		"out-pub", *cf.outPubPath,
-	); err != nil {
-		return err
-	}
-
 	if isP11 {
 		p11Client, err := pkclient.FromUrl(*cf.p11url)
 		if err != nil {
@@ -92,12 +82,12 @@ func keygen(args []string, out io.Writer, errOut io.Writer) error {
 			return fmt.Errorf("error while getting public key: %w", err)
 		}
 	} else {
-		err = writeOutput(*cf.outKeyPath, cert.MarshalPrivateKeyToPEM(curve, rawPriv), 0600, out)
+		err = os.WriteFile(*cf.outKeyPath, cert.MarshalPrivateKeyToPEM(curve, rawPriv), 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-key: %s", err)
 		}
 	}
-	err = writeOutput(*cf.outPubPath, cert.MarshalPublicKeyToPEM(curve, pub), 0600, out)
+	err = os.WriteFile(*cf.outPubPath, cert.MarshalPublicKeyToPEM(curve, pub), 0600)
 	if err != nil {
 		return fmt.Errorf("error while writing out-pub: %s", err)
 	}
@@ -112,7 +102,6 @@ func keygenSummary() string {
 func keygenHelp(out io.Writer) {
 	cf := newKeygenFlags()
 	_, _ = out.Write([]byte("Usage of " + os.Args[0] + " " + keygenSummary() + "\n"))
-	_, _ = out.Write([]byte(stdioHelpText))
 	cf.set.SetOutput(out)
 	cf.set.PrintDefaults()
 }

cmd/nebula-cert/keygen_test.go

@@ -20,7 +20,6 @@ func Test_keygenHelp(t *testing.T) {
 	assert.Equal(
 		t,
 		"Usage of "+os.Args[0]+" keygen <flags>: create a public/private key pair. the public key can be passed to `nebula-cert sign`\n"+
-			"  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"+
 			"  -curve string\n"+
 			"    \tECDH Curve (25519, P256) (default \"25519\")\n"+
 			"  -out-key string\n"+
@@ -94,43 +93,3 @@ func Test_keygen(t *testing.T) {
 	require.NoError(t, err)
 	assert.Len(t, lPub, 32)
 }
-
-func Test_keygen_stdio(t *testing.T) {
-	keyF, err := os.CreateTemp("", "test.key")
-	require.NoError(t, err)
-	os.Remove(keyF.Name())
-	defer os.Remove(keyF.Name())
-
-	pubF, err := os.CreateTemp("", "test.pub")
-	require.NoError(t, err)
-	os.Remove(pubF.Name())
-	defer os.Remove(pubF.Name())
-
-	// out-pub on stdout, out-key on disk
-	ob := &bytes.Buffer{}
-	eb := &bytes.Buffer{}
-	require.NoError(t, keygen([]string{"-out-pub", "-", "-out-key", keyF.Name()}, ob, eb))
-	assert.Empty(t, eb.String())
-	lPub, _, curve, err := cert.UnmarshalPublicKeyFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, cert.Curve_CURVE25519, curve)
-	assert.Len(t, lPub, 32)
-
-	// out-key on stdout, out-pub on disk
-	os.Remove(keyF.Name())
-	ob.Reset()
-	eb.Reset()
-	require.NoError(t, keygen([]string{"-out-pub", pubF.Name(), "-out-key", "-"}, ob, eb))
-	assert.Empty(t, eb.String())
-	lKey, _, curve, err := cert.UnmarshalPrivateKeyFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, cert.Curve_CURVE25519, curve)
-	assert.Len(t, lKey, 32)
-
-	// both on stdout is a conflict caught up front
-	ob.Reset()
-	eb.Reset()
-	require.EqualError(t, keygen([]string{"-out-pub", "-", "-out-key", "-"}, ob, eb),
-		`-out-key and -out-pub both set to "-", only one output may write to stdout`)
-	assert.Empty(t, ob.String())
-}

cmd/nebula-cert/passwords.go

@@ -22,9 +22,7 @@ func (pr StdinPasswordReader) ReadPassword() ([]byte, error) {
 	}
 
 	password, err := term.ReadPassword(int(os.Stdin.Fd()))
-	// Terminal echo is off while reading, so the user's Enter key does not
-	// produce a visible newline. Emit one on stderr to match the prompt.
-	fmt.Fprintln(os.Stderr)
+	fmt.Println()
 
 	return password, err
 }

cmd/nebula-cert/print.go

@@ -40,23 +40,11 @@ func printCert(args []string, out io.Writer, errOut io.Writer) error {
 		return err
 	}
 
-	var claims ioClaims
-	if err := reserveInputs(&claims, "path", *pf.path); err != nil {
-		return err
-	}
-	if err := reserveOutputs(&claims, "out-qr", *pf.outQRPath); err != nil {
-		return err
-	}
-
-	rawCert, err := readInput("path", *pf.path, &claims)
+	rawCert, err := os.ReadFile(*pf.path)
 	if err != nil {
 		return fmt.Errorf("unable to read cert; %s", err)
 	}
 
-	// When the QR is going to stdout, suppress the human-readable text/json
-	// output so the binary stream is not contaminated.
-	qrToStdout := isStdio(*pf.outQRPath)
-
 	var c cert.Certificate
 	var qrBytes []byte
 	part := 0
@@ -69,13 +57,11 @@ func printCert(args []string, out io.Writer, errOut io.Writer) error {
 			return fmt.Errorf("error while unmarshaling cert: %s", err)
 		}
 
-		if !qrToStdout {
-			if *pf.json {
-				jsonCerts = append(jsonCerts, c)
-			} else {
-				_, _ = out.Write([]byte(c.String()))
-				_, _ = out.Write([]byte("\n"))
-			}
+		if *pf.json {
+			jsonCerts = append(jsonCerts, c)
+		} else {
+			_, _ = out.Write([]byte(c.String()))
+			_, _ = out.Write([]byte("\n"))
 		}
 
 		if *pf.outQRPath != "" {
@@ -93,7 +79,7 @@ func printCert(args []string, out io.Writer, errOut io.Writer) error {
 		part++
 	}
 
-	if *pf.json && !qrToStdout {
+	if *pf.json {
 		b, _ := json.Marshal(jsonCerts)
 		_, _ = out.Write(b)
 		_, _ = out.Write([]byte("\n"))
@@ -105,7 +91,7 @@ func printCert(args []string, out io.Writer, errOut io.Writer) error {
 			return fmt.Errorf("error while generating qr code: %s", err)
 		}
 
-		err = writeOutput(*pf.outQRPath, b, 0600, out)
+		err = os.WriteFile(*pf.outQRPath, b, 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-qr: %s", err)
 		}
@@ -121,7 +107,6 @@ func printSummary() string {
 func printHelp(out io.Writer) {
 	pf := newPrintFlags()
 	out.Write([]byte("Usage of " + os.Args[0] + " " + printSummary() + "\n"))
-	out.Write([]byte(stdioHelpText))
 	pf.set.SetOutput(out)
 	pf.set.PrintDefaults()
 }

cmd/nebula-cert/print_test.go

@@ -25,7 +25,6 @@ func Test_printHelp(t *testing.T) {
 	assert.Equal(
 		t,
 		"Usage of "+os.Args[0]+" print <flags>: prints details about a certificate\n"+
-			"  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"+
 			"  -json\n"+
 			"    \tOptional: outputs certificates in json format\n"+
 			"  -out-qr string\n"+
@@ -179,44 +178,6 @@ func Test_printCert(t *testing.T) {
 		ob.String(),
 	)
 	assert.Empty(t, eb.String())
-
-	// read cert from stdin
-	ob.Reset()
-	eb.Reset()
-	withStdin(t, bytes.NewReader(p))
-	err = printCert([]string{"-json", "-path", "-"}, ob, eb)
-	require.NoError(t, err)
-	assert.Equal(
-		t,
-		`[{"details":{"curve":"CURVE25519","groups":["hi"],"isCa":false,"issuer":"`+c.Issuer()+`","name":"test","networks":["10.0.0.123/8"],"notAfter":"0001-01-01T00:00:00Z","notBefore":"0001-01-01T00:00:00Z","publicKey":"`+pk+`","unsafeNetworks":[]},"fingerprint":"`+fp+`","signature":"`+sig+`","version":1}]
-`,
-		ob.String(),
-	)
-	assert.Empty(t, eb.String())
-
-	// -out-qr - sends only the PNG to stdout, suppressing the cert dump
-	ob.Reset()
-	eb.Reset()
-	withStdin(t, bytes.NewReader(p))
-	err = printCert([]string{"-path", "-", "-out-qr", "-"}, ob, eb)
-	require.NoError(t, err)
-	assert.Empty(t, eb.String())
-	stdout := ob.Bytes()
-	require.NotEmpty(t, stdout)
-	// PNG magic, no PEM/JSON noise prepended
-	assert.Equal(t, []byte{0x89, 'P', 'N', 'G', 0x0d, 0x0a, 0x1a, 0x0a}, stdout[:8])
-	assert.NotContains(t, string(stdout), "NebulaCertificate")
-	assert.NotContains(t, string(stdout), `"details"`)
-
-	// json + out-qr - still suppresses json
-	ob.Reset()
-	eb.Reset()
-	withStdin(t, bytes.NewReader(p))
-	err = printCert([]string{"-json", "-path", "-", "-out-qr", "-"}, ob, eb)
-	require.NoError(t, err)
-	assert.Empty(t, eb.String())
-	assert.Equal(t, []byte{0x89, 'P', 'N', 'G'}, ob.Bytes()[:4])
-	assert.NotContains(t, ob.String(), `"details"`)
 }
 
 // NewTestCaCert will generate a CA cert

cmd/nebula-cert/sign.go

@@ -85,9 +85,6 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 	if !isP11 && *sf.inPubPath != "" && *sf.outKeyPath != "" {
 		return newHelpErrorf("cannot set both -in-pub and -out-key")
 	}
-	if isP11 && *sf.outKeyPath != "" {
-		return newHelpErrorf("cannot set -out-key with -pkcs11")
-	}
 
 	var v4Networks []netip.Prefix
 	var v6Networks []netip.Prefix
@@ -105,35 +102,13 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		return newHelpErrorf("-version must be either %v or %v", cert.Version1, cert.Version2)
 	}
 
-	if *sf.outKeyPath == "" {
-		*sf.outKeyPath = *sf.name + ".key"
-	}
-	if *sf.outCertPath == "" {
-		*sf.outCertPath = *sf.name + ".crt"
-	}
-
-	var claims ioClaims
-	if err := reserveInputs(&claims,
-		"ca-key", *sf.caKeyPath,
-		"ca-crt", *sf.caCertPath,
-		"in-pub", *sf.inPubPath,
-	); err != nil {
-		return err
-	}
-	if err := reserveOutputs(&claims,
-		"out-key", *sf.outKeyPath,
-		"out-crt", *sf.outCertPath,
-		"out-qr", *sf.outQRPath,
-	); err != nil {
-		return err
-	}
-
 	var curve cert.Curve
 	var caKey []byte
 
 	if !isP11 {
 		var rawCAKey []byte
-		rawCAKey, err = readInput("ca-key", *sf.caKeyPath, &claims)
+		rawCAKey, err := os.ReadFile(*sf.caKeyPath)
+
 		if err != nil {
 			return fmt.Errorf("error while reading ca-key: %s", err)
 		}
@@ -146,7 +121,7 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 			if len(passphrase) == 0 {
 				// ask for a passphrase until we get one
 				for i := 0; i < 5; i++ {
-					errOut.Write([]byte("Enter passphrase: "))
+					out.Write([]byte("Enter passphrase: "))
 					passphrase, err = pr.ReadPassword()
 
 					if errors.Is(err, ErrNoTerminal) {
@@ -172,7 +147,7 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		}
 	}
 
-	rawCACert, err := readInput("ca-crt", *sf.caCertPath, &claims)
+	rawCACert, err := os.ReadFile(*sf.caCertPath)
 	if err != nil {
 		return fmt.Errorf("error while reading ca-crt: %s", err)
 	}
@@ -270,7 +245,7 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 
 	if *sf.inPubPath != "" {
 		var pubCurve cert.Curve
-		rawPub, err := readInput("in-pub", *sf.inPubPath, &claims)
+		rawPub, err := os.ReadFile(*sf.inPubPath)
 		if err != nil {
 			return fmt.Errorf("error while reading in-pub: %s", err)
 		}
@@ -291,10 +266,16 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		pub, rawPriv = newKeypair(curve)
 	}
 
-	if !isStdio(*sf.outCertPath) {
-		if _, err := os.Stat(*sf.outCertPath); err == nil {
-			return fmt.Errorf("refusing to overwrite existing cert: %s", *sf.outCertPath)
-		}
+	if *sf.outKeyPath == "" {
+		*sf.outKeyPath = *sf.name + ".key"
+	}
+
+	if *sf.outCertPath == "" {
+		*sf.outCertPath = *sf.name + ".crt"
+	}
+
+	if _, err := os.Stat(*sf.outCertPath); err == nil {
+		return fmt.Errorf("refusing to overwrite existing cert: %s", *sf.outCertPath)
 	}
 
 	var crts []cert.Certificate
@@ -379,13 +360,11 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 	}
 
 	if !isP11 && *sf.inPubPath == "" {
-		if !isStdio(*sf.outKeyPath) {
-			if _, err := os.Stat(*sf.outKeyPath); err == nil {
-				return fmt.Errorf("refusing to overwrite existing key: %s", *sf.outKeyPath)
-			}
+		if _, err := os.Stat(*sf.outKeyPath); err == nil {
+			return fmt.Errorf("refusing to overwrite existing key: %s", *sf.outKeyPath)
 		}
 
-		err = writeOutput(*sf.outKeyPath, cert.MarshalPrivateKeyToPEM(curve, rawPriv), 0600, out)
+		err = os.WriteFile(*sf.outKeyPath, cert.MarshalPrivateKeyToPEM(curve, rawPriv), 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-key: %s", err)
 		}
@@ -400,7 +379,7 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 		b = append(b, sb...)
 	}
 
-	err = writeOutput(*sf.outCertPath, b, 0600, out)
+	err = os.WriteFile(*sf.outCertPath, b, 0600)
 	if err != nil {
 		return fmt.Errorf("error while writing out-crt: %s", err)
 	}
@@ -411,7 +390,7 @@ func signCert(args []string, out io.Writer, errOut io.Writer, pr PasswordReader)
 			return fmt.Errorf("error while generating qr code: %s", err)
 		}
 
-		err = writeOutput(*sf.outQRPath, b, 0600, out)
+		err = os.WriteFile(*sf.outQRPath, b, 0600)
 		if err != nil {
 			return fmt.Errorf("error while writing out-qr: %s", err)
 		}
@@ -461,7 +440,6 @@ func signSummary() string {
 func signHelp(out io.Writer) {
 	sf := newSignFlags()
 	out.Write([]byte("Usage of " + os.Args[0] + " " + signSummary() + "\n"))
-	out.Write([]byte(stdioHelpText))
 	sf.set.SetOutput(out)
 	sf.set.PrintDefaults()
 }

cmd/nebula-cert/sign_test.go

@@ -27,7 +27,6 @@ func Test_signHelp(t *testing.T) {
 	assert.Equal(
 		t,
 		"Usage of "+os.Args[0]+" sign <flags>: create and sign a certificate\n"+
-			"  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"+
 			"  -ca-crt string\n"+
 			"    \tOptional: path to the signing CA cert (default \"ca.crt\")\n"+
 			"  -ca-key string\n"+
@@ -377,18 +376,15 @@ func Test_signCert(t *testing.T) {
 	// test with the proper 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.NoError(t, signCert(args, ob, eb, testpw))
-	assert.Empty(t, ob.String())
-	assert.Equal(t, "Enter passphrase: ", eb.String())
+	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))
-	ob.Reset()
-	eb.Reset()
 	require.NoError(t, signCert(args, ob, eb, testpw))
-	assert.Empty(t, ob.String())
 	assert.Empty(t, eb.String())
 	os.Setenv("NEBULA_CA_PASSPHRASE", "")
 
@@ -399,8 +395,8 @@ func Test_signCert(t *testing.T) {
 	testpw.password = []byte("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.Error(t, signCert(args, ob, eb, testpw))
-	assert.Empty(t, ob.String())
-	assert.Equal(t, "Enter passphrase: ", eb.String())
+	assert.Equal(t, "Enter passphrase: ", ob.String())
+	assert.Empty(t, eb.String())
 
 	// test with the wrong password in environment
 	ob.Reset()
@@ -420,8 +416,8 @@ func Test_signCert(t *testing.T) {
 	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.Error(t, signCert(args, ob, eb, nopw))
 	// normally the user hitting enter on the prompt would add newlines between these
-	assert.Empty(t, ob.String())
-	assert.Equal(t, "Enter passphrase: Enter passphrase: Enter passphrase: Enter passphrase: Enter passphrase: ", eb.String())
+	assert.Equal(t, "Enter passphrase: Enter passphrase: Enter passphrase: Enter passphrase: Enter passphrase: ", ob.String())
+	assert.Empty(t, eb.String())
 
 	// test an error condition
 	ob.Reset()
@@ -429,106 +425,6 @@ func Test_signCert(t *testing.T) {
 
 	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.Error(t, signCert(args, ob, eb, errpw))
-	assert.Empty(t, ob.String())
-	assert.Equal(t, "Enter passphrase: ", eb.String())
-}
-
-func Test_signCert_stdio(t *testing.T) {
-	nopw := &StubPasswordReader{
-		password: []byte(""),
-		err:      nil,
-	}
-
-	caPub, caPriv, _ := ed25519.GenerateKey(rand.Reader)
-	rawCAKey := cert.MarshalSigningPrivateKeyToPEM(cert.Curve_CURVE25519, caPriv)
-
-	ca, _ := NewTestCaCert("ca", caPub, caPriv, time.Now(), time.Now().Add(time.Minute*200), nil, nil, nil)
-	rawCACrt, _ := ca.MarshalPEM()
-
-	caCrtF, err := os.CreateTemp("", "sign-cert.crt")
-	require.NoError(t, err)
-	defer os.Remove(caCrtF.Name())
-	caCrtF.Write(rawCACrt)
-
-	caKeyF, err := os.CreateTemp("", "sign-cert.key")
-	require.NoError(t, err)
-	defer os.Remove(caKeyF.Name())
-	caKeyF.Write(rawCAKey)
-
-	keyF, err := os.CreateTemp("", "sign.key")
-	require.NoError(t, err)
-	os.Remove(keyF.Name())
-	defer os.Remove(keyF.Name())
-
-	// ca-key on stdin, cert to stdout
-	withStdin(t, bytes.NewReader(rawCAKey))
-	ob := &bytes.Buffer{}
-	eb := &bytes.Buffer{}
-	args := []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", "-", "-name", "stdin-test", "-ip", "1.1.1.1/24", "-out-crt", "-", "-out-key", keyF.Name(), "-duration", "100m"}
-	require.NoError(t, signCert(args, ob, eb, nopw))
-	assert.Empty(t, eb.String())
-
-	lCrt, _, err := cert.UnmarshalCertificateFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, "stdin-test", lCrt.Name())
-	assert.True(t, lCrt.CheckSignature(caPub))
-
-	// two flags reading from stdin should error before any read attempt;
-	// otherwise an interactive shell would hang on io.ReadAll
-	stdinIn := bytes.NewReader(rawCAKey)
-	withStdin(t, stdinIn)
-	ob.Reset()
-	eb.Reset()
-	args = []string{"-version", "1", "-ca-crt", "-", "-ca-key", "-", "-name", "stdin-test", "-ip", "1.1.1.1/24", "-out-crt", "nope", "-out-key", "nope", "-duration", "100m"}
-	require.EqualError(t, signCert(args, ob, eb, nopw),
-		`-ca-key and -ca-crt both set to "-", only one input may read from stdin`)
-	assert.Equal(t, len(rawCAKey), stdinIn.Len(), "stdin should be untouched when conflict is caught up front")
-
-	// two flags writing to stdout should error before any output is written
-	// AND before stdin is consumed
-	stdinR := bytes.NewReader(rawCAKey)
-	withStdin(t, stdinR)
-	ob.Reset()
-	eb.Reset()
-	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", "-", "-name", "stdin-test", "-ip", "1.1.1.1/24", "-out-crt", "-", "-out-key", "-", "-duration", "100m"}
-	require.EqualError(t, signCert(args, ob, eb, nopw),
-		`-out-key and -out-crt both set to "-", only one output may write to stdout`)
-	assert.Empty(t, ob.String())
-	// stdin should be untouched because the conflict was caught up front
-	assert.Equal(t, len(rawCAKey), stdinR.Len())
-
-	// out-key on stdout, cert on disk
-	keyF2, err := os.CreateTemp("", "sign.key")
-	require.NoError(t, err)
-	os.Remove(keyF2.Name())
-	defer os.Remove(keyF2.Name())
-	crtF, err := os.CreateTemp("", "sign.crt")
-	require.NoError(t, err)
-	os.Remove(crtF.Name())
-	defer os.Remove(crtF.Name())
-
-	ob.Reset()
-	eb.Reset()
-	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "stdin-test", "-ip", "1.1.1.1/24", "-out-crt", crtF.Name(), "-out-key", "-", "-duration", "100m"}
-	require.NoError(t, signCert(args, ob, eb, nopw))
-	assert.Empty(t, eb.String())
-	_, _, curve, err := cert.UnmarshalPrivateKeyFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, cert.Curve_CURVE25519, curve)
-
-	// in-pub on stdin (caller already has a keypair, only the cert is generated)
-	inPub, _ := x25519Keypair()
-	rawInPub := cert.MarshalPublicKeyToPEM(cert.Curve_CURVE25519, inPub)
-
-	withStdin(t, bytes.NewReader(rawInPub))
-	os.Remove(crtF.Name())
-	ob.Reset()
-	eb.Reset()
-	args = []string{"-version", "1", "-ca-crt", caCrtF.Name(), "-ca-key", caKeyF.Name(), "-name", "in-pub-test", "-ip", "1.1.1.1/24", "-in-pub", "-", "-out-crt", "-", "-duration", "100m"}
-	require.NoError(t, signCert(args, ob, eb, nopw))
-	assert.Empty(t, eb.String())
-	stdinCrt, _, err := cert.UnmarshalCertificateFromPEM(ob.Bytes())
-	require.NoError(t, err)
-	assert.Equal(t, "in-pub-test", stdinCrt.Name())
-	assert.Equal(t, inPub, stdinCrt.PublicKey())
+	assert.Equal(t, "Enter passphrase: ", ob.String())
+	assert.Empty(t, eb.String())
 }

cmd/nebula-cert/stdio.go

@@ -1,117 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"io"
-	"os"
-)
-
-// stdioPath is the special path value that selects stdin (for inputs) or
-// stdout (for outputs) instead of a file on disk.
-const stdioPath = "-"
-
-// stdioHelpText is rendered just under the Usage line of each subcommand
-// help so the - convention is documented once instead of on every flag.
-const stdioHelpText = "  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"
-
-// stdinReader is the source used when an input flag is set to "-".
-// It is a package level var so tests can swap in a deterministic reader.
-// Tests that mutate stdinReader cannot run with t.Parallel().
-var stdinReader io.Reader = os.Stdin
-
-// ioClaims tracks which flags have claimed stdin and stdout during a single
-// command invocation so we can refuse a second flag asking for the same
-// stream.
-type ioClaims struct {
-	in  string
-	out string
-}
-
-func (c *ioClaims) claimIn(flagName string) error {
-	if c.in != "" && c.in != flagName {
-		return fmt.Errorf("-%s and -%s both set to %q, only one input may read from stdin", c.in, flagName, stdioPath)
-	}
-	c.in = flagName
-	return nil
-}
-
-func (c *ioClaims) claimOut(flagName string) error {
-	if c.out != "" && c.out != flagName {
-		return fmt.Errorf("-%s and -%s both set to %q, only one output may write to stdout", c.out, flagName, stdioPath)
-	}
-	c.out = flagName
-	return nil
-}
-
-// reserveInputs walks alternating (flagName, path) pairs and claims stdin
-// for any path equal to stdioPath. It must be called before any input is
-// read so a conflict can be reported immediately instead of blocking on
-// io.ReadAll while waiting for input that will never arrive.
-func reserveInputs(claims *ioClaims, pairs ...string) error {
-	return reserveStdio(claims, "reserveInputs", (*ioClaims).claimIn, pairs)
-}
-
-// reserveOutputs walks alternating (flagName, path) pairs and claims stdout
-// for any path equal to stdioPath. It must be called before any output is
-// written so a conflict cannot leave one stream half written before the
-// second flag fails.
-func reserveOutputs(claims *ioClaims, pairs ...string) error {
-	return reserveStdio(claims, "reserveOutputs", (*ioClaims).claimOut, pairs)
-}
-
-func reserveStdio(claims *ioClaims, who string, claim func(*ioClaims, string) error, pairs []string) error {
-	if len(pairs)%2 != 0 {
-		panic(who + " requires alternating name, path pairs")
-	}
-	for i := 0; i < len(pairs); i += 2 {
-		name, path := pairs[i], pairs[i+1]
-		if path != stdioPath {
-			continue
-		}
-		if err := claim(claims, name); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// readInput returns the bytes referenced by path, reading from stdin when
-// path is stdioPath.
-func readInput(flagName, path string, claims *ioClaims) ([]byte, error) {
-	if path == stdioPath {
-		if err := claims.claimIn(flagName); err != nil {
-			return nil, err
-		}
-		return io.ReadAll(stdinReader)
-	}
-	return os.ReadFile(path)
-}
-
-// openInput returns a reader for path. When path is stdioPath the returned
-// reader wraps stdin and Close is a no-op.
-func openInput(flagName, path string, claims *ioClaims) (io.ReadCloser, error) {
-	if path == stdioPath {
-		if err := claims.claimIn(flagName); err != nil {
-			return nil, err
-		}
-		return io.NopCloser(stdinReader), nil
-	}
-	return os.Open(path)
-}
-
-// writeOutput writes data to path, or to stdout when path is stdioPath. perm
-// is only used for file output. The caller must have already claimed stdout
-// via reserveOutputs before invoking with stdioPath.
-func writeOutput(path string, data []byte, perm os.FileMode, stdout io.Writer) error {
-	if path == stdioPath {
-		_, err := stdout.Write(data)
-		return err
-	}
-	return os.WriteFile(path, data, perm)
-}
-
-// isStdio reports whether path is the stdio sentinel and so should skip
-// existence checks like "refuse to overwrite".
-func isStdio(path string) bool {
-	return path == stdioPath
-}

cmd/nebula-cert/stdio_test.go

@@ -1,167 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"io"
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// withStdin temporarily replaces stdinReader for the duration of t.
-func withStdin(t *testing.T, r io.Reader) {
-	t.Helper()
-	prev := stdinReader
-	stdinReader = r
-	t.Cleanup(func() { stdinReader = prev })
-}
-
-func Test_readInput_stdin(t *testing.T) {
-	withStdin(t, bytes.NewBufferString("hello"))
-	var claims ioClaims
-
-	got, err := readInput("path", "-", &claims)
-	require.NoError(t, err)
-	assert.Equal(t, []byte("hello"), got)
-	assert.Equal(t, "path", claims.in)
-}
-
-func Test_readInput_file(t *testing.T) {
-	dir := t.TempDir()
-	p := filepath.Join(dir, "f")
-	require.NoError(t, os.WriteFile(p, []byte("file"), 0600))
-	var claims ioClaims
-
-	got, err := readInput("path", p, &claims)
-	require.NoError(t, err)
-	assert.Equal(t, []byte("file"), got)
-	assert.Empty(t, claims.in)
-}
-
-func Test_readInput_doubleStdinErrors(t *testing.T) {
-	withStdin(t, bytes.NewBufferString("hello"))
-	var claims ioClaims
-
-	_, err := readInput("ca-key", "-", &claims)
-	require.NoError(t, err)
-
-	_, err = readInput("ca-crt", "-", &claims)
-	require.EqualError(t, err, `-ca-key and -ca-crt both set to "-", only one input may read from stdin`)
-}
-
-func Test_openInput_stdin(t *testing.T) {
-	withStdin(t, bytes.NewBufferString("hi"))
-	var claims ioClaims
-
-	r, err := openInput("ca", "-", &claims)
-	require.NoError(t, err)
-	defer r.Close()
-	b, err := io.ReadAll(r)
-	require.NoError(t, err)
-	assert.Equal(t, []byte("hi"), b)
-}
-
-func Test_openInput_doubleStdinErrors(t *testing.T) {
-	withStdin(t, bytes.NewBufferString("hi"))
-	var claims ioClaims
-
-	r, err := openInput("ca", "-", &claims)
-	require.NoError(t, err)
-	r.Close()
-
-	_, err = openInput("crt", "-", &claims)
-	require.EqualError(t, err, `-ca and -crt both set to "-", only one input may read from stdin`)
-}
-
-func Test_writeOutput_stdout(t *testing.T) {
-	out := &bytes.Buffer{}
-
-	err := writeOutput("-", []byte("payload"), 0600, out)
-	require.NoError(t, err)
-	assert.Equal(t, "payload", out.String())
-}
-
-func Test_writeOutput_file(t *testing.T) {
-	dir := t.TempDir()
-	p := filepath.Join(dir, "f")
-	out := &bytes.Buffer{}
-
-	err := writeOutput(p, []byte("payload"), 0600, out)
-	require.NoError(t, err)
-	assert.Empty(t, out.String())
-	got, err := os.ReadFile(p)
-	require.NoError(t, err)
-	assert.Equal(t, []byte("payload"), got)
-}
-
-func Test_reserveOutputs_noConflict(t *testing.T) {
-	var claims ioClaims
-	require.NoError(t, reserveOutputs(&claims,
-		"out-key", "/tmp/key",
-		"out-crt", "-",
-		"out-qr", "",
-	))
-	assert.Equal(t, "out-crt", claims.out)
-}
-
-func Test_reserveOutputs_conflict(t *testing.T) {
-	var claims ioClaims
-	err := reserveOutputs(&claims,
-		"out-key", "-",
-		"out-crt", "-",
-	)
-	require.EqualError(t, err, `-out-key and -out-crt both set to "-", only one output may write to stdout`)
-}
-
-func Test_reserveOutputs_panicsOnOddPairs(t *testing.T) {
-	defer func() {
-		r := recover()
-		require.NotNil(t, r)
-	}()
-	var claims ioClaims
-	_ = reserveOutputs(&claims, "out-key")
-}
-
-func Test_reserveInputs_noConflict(t *testing.T) {
-	var claims ioClaims
-	require.NoError(t, reserveInputs(&claims,
-		"ca-key", "/tmp/ca.key",
-		"ca-crt", "-",
-		"in-pub", "",
-	))
-	assert.Equal(t, "ca-crt", claims.in)
-}
-
-func Test_reserveInputs_conflict(t *testing.T) {
-	var claims ioClaims
-	err := reserveInputs(&claims,
-		"ca-key", "-",
-		"ca-crt", "-",
-	)
-	require.EqualError(t, err, `-ca-key and -ca-crt both set to "-", only one input may read from stdin`)
-}
-
-func Test_claimIn_idempotent(t *testing.T) {
-	// pre-claim then a lazy re-claim of the same flag should be a no-op
-	var claims ioClaims
-	require.NoError(t, claims.claimIn("ca-key"))
-	require.NoError(t, claims.claimIn("ca-key"))
-	assert.Equal(t, "ca-key", claims.in)
-}
-
-func Test_claimOut_idempotent(t *testing.T) {
-	var claims ioClaims
-	require.NoError(t, claims.claimOut("out-crt"))
-	require.NoError(t, claims.claimOut("out-crt"))
-	assert.Equal(t, "out-crt", claims.out)
-}
-
-func Test_isStdio(t *testing.T) {
-	assert.True(t, isStdio("-"))
-	assert.False(t, isStdio(""))
-	assert.False(t, isStdio("./-"))
-	assert.False(t, isStdio("foo"))
-}

cmd/nebula-cert/verify.go

@@ -39,26 +39,18 @@ func verify(args []string, out io.Writer, errOut io.Writer) error {
 		return err
 	}
 
-	var claims ioClaims
-	if err := reserveInputs(&claims,
-		"ca", *vf.caPath,
-		"crt", *vf.certPath,
-	); err != nil {
-		return err
-	}
-
-	caReader, err := openInput("ca", *vf.caPath, &claims)
+	caFile, err := os.Open(*vf.caPath)
 	if err != nil {
 		return fmt.Errorf("error while reading ca: %w", err)
 	}
-	defer caReader.Close()
+	defer caFile.Close()
 
-	caPool, err := cert.NewCAPoolFromPEMReader(caReader)
+	caPool, err := cert.NewCAPoolFromPEMReader(caFile)
 	if err != nil && !errors.Is(err, cert.ErrExpired) {
 		return fmt.Errorf("error while adding ca cert to pool: %w", err)
 	}
 
-	rawCert, err := readInput("crt", *vf.certPath, &claims)
+	rawCert, err := os.ReadFile(*vf.certPath)
 	if err != nil {
 		return fmt.Errorf("unable to read crt: %w", err)
 	}
@@ -93,7 +85,6 @@ func verifySummary() string {
 func verifyHelp(out io.Writer) {
 	vf := newVerifyFlags()
 	_, _ = out.Write([]byte("Usage of " + os.Args[0] + " " + verifySummary() + "\n"))
-	_, _ = out.Write([]byte(stdioHelpText))
 	vf.set.SetOutput(out)
 	vf.set.PrintDefaults()
 }

cmd/nebula-cert/verify_test.go

@@ -23,7 +23,6 @@ func Test_verifyHelp(t *testing.T) {
 	assert.Equal(
 		t,
 		"Usage of "+os.Args[0]+" verify <flags>: verifies a certificate isn't expired and was signed by a trusted authority.\n"+
-			"  Pass \"-\" to any path flag to read from stdin or write to stdout.\n"+
 			"  -ca string\n"+
 			"    \tRequired: path to a file containing one or more ca certificates\n"+
 			"  -crt string\n"+
@@ -123,46 +122,3 @@ func Test_verify(t *testing.T) {
 	assert.Empty(t, eb.String())
 	require.NoError(t, err)
 }
-
-func Test_verify_stdio(t *testing.T) {
-	ob := &bytes.Buffer{}
-	eb := &bytes.Buffer{}
-
-	caPub, caPriv, _ := ed25519.GenerateKey(rand.Reader)
-	ca, _ := NewTestCaCert("test-ca", caPub, caPriv, time.Now().Add(time.Hour*-1), time.Now().Add(time.Hour*2), nil, nil, nil)
-	caPEM, _ := ca.MarshalPEM()
-
-	crt, _ := NewTestCert(ca, caPriv, "test-cert", time.Now().Add(time.Hour*-1), time.Now().Add(time.Hour), nil, nil, nil)
-	crtPEM, _ := crt.MarshalPEM()
-
-	caFile, err := os.CreateTemp("", "verify-ca")
-	require.NoError(t, err)
-	defer os.Remove(caFile.Name())
-	caFile.Write(caPEM)
-
-	// crt on stdin, ca on disk
-	withStdin(t, bytes.NewReader(crtPEM))
-	require.NoError(t, verify([]string{"-ca", caFile.Name(), "-crt", "-"}, ob, eb))
-	assert.Empty(t, ob.String())
-	assert.Empty(t, eb.String())
-
-	// ca on stdin, crt on disk
-	certFile, err := os.CreateTemp("", "verify-cert")
-	require.NoError(t, err)
-	defer os.Remove(certFile.Name())
-	certFile.Write(crtPEM)
-
-	withStdin(t, bytes.NewReader(caPEM))
-	ob.Reset()
-	eb.Reset()
-	require.NoError(t, verify([]string{"-ca", "-", "-crt", certFile.Name()}, ob, eb))
-	assert.Empty(t, ob.String())
-	assert.Empty(t, eb.String())
-
-	// both flags on stdin should error
-	withStdin(t, bytes.NewReader(caPEM))
-	ob.Reset()
-	eb.Reset()
-	require.EqualError(t, verify([]string{"-ca", "-", "-crt", "-"}, ob, eb),
-		`-ca and -crt both set to "-", only one input may read from stdin`)
-}

cmd/nebula-service/main.go

@@ -61,12 +61,9 @@ func main() {
 	}
 
 	if *configPath == "" {
-		p, err := config.DefaultPath()
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-		*configPath = p
+		fmt.Println("-config flag must be set")
+		flag.Usage()
+		os.Exit(1)
 	}
 
 	c := config.NewC(l)

cmd/nebula-service/service.go

@@ -3,6 +3,8 @@ package main
 import (
 	"fmt"
 	"log"
+	"os"
+	"path/filepath"
 
 	"github.com/kardianos/service"
 	"github.com/slackhq/nebula"
@@ -55,13 +57,24 @@ func (p *program) Stop(s service.Service) error {
 	return nil
 }
 
+func fileExists(filename string) bool {
+	_, err := os.Stat(filename)
+	if os.IsNotExist(err) {
+		return false
+	}
+	return true
+}
+
 func doService(configPath *string, configTest *bool, build string, serviceFlag *string) error {
 	if *configPath == "" {
-		p, err := config.DefaultPath()
+		ex, err := os.Executable()
 		if err != nil {
 			return err
 		}
-		*configPath = p
+		*configPath = filepath.Dir(ex) + "/config.yaml"
+		if !fileExists(*configPath) {
+			*configPath = filepath.Dir(ex) + "/config.yml"
+		}
 	}
 
 	svcConfig := &service.Config{

cmd/nebula/main.go

@@ -50,12 +50,9 @@ func main() {
 	}
 
 	if *configPath == "" {
-		p, err := config.DefaultPath()
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-		*configPath = p
+		fmt.Println("-config flag must be set")
+		flag.Usage()
+		os.Exit(1)
 	}
 
 	l := logging.NewLogger(os.Stdout)

config/default.go

@@ -1,29 +0,0 @@
-package config
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-)
-
-// DefaultPath returns a path to a config file alongside the running executable, preferring config.yaml over config.yml.
-// If neither file exists an error is returned that names both paths checked.
-func DefaultPath() (string, error) {
-	ex, err := os.Executable()
-	if err != nil {
-		return "", err
-	}
-	return defaultPathInDir(filepath.Dir(ex))
-}
-
-func defaultPathInDir(dir string) (string, error) {
-	yamlPath := filepath.Join(dir, "config.yaml")
-	if _, err := os.Stat(yamlPath); err == nil {
-		return yamlPath, nil
-	}
-	ymlPath := filepath.Join(dir, "config.yml")
-	if _, err := os.Stat(ymlPath); err == nil {
-		return ymlPath, nil
-	}
-	return "", fmt.Errorf("no default config found at %s or %s", yamlPath, ymlPath)
-}

config/default_test.go

@@ -1,67 +0,0 @@
-package config
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestDefaultPathInDir(t *testing.T) {
-	t.Run("prefers config.yaml when both exist", func(t *testing.T) {
-		dir := t.TempDir()
-		want := filepath.Join(dir, "config.yaml")
-		other := filepath.Join(dir, "config.yml")
-		require.NoError(t, os.WriteFile(want, []byte("a: 1"), 0644))
-		require.NoError(t, os.WriteFile(other, []byte("a: 2"), 0644))
-
-		got, err := defaultPathInDir(dir)
-		require.NoError(t, err)
-		assert.Equal(t, want, got)
-	})
-
-	t.Run("returns config.yaml when only it exists", func(t *testing.T) {
-		dir := t.TempDir()
-		want := filepath.Join(dir, "config.yaml")
-		require.NoError(t, os.WriteFile(want, []byte("a: 1"), 0644))
-
-		got, err := defaultPathInDir(dir)
-		require.NoError(t, err)
-		assert.Equal(t, want, got)
-	})
-
-	t.Run("falls back to config.yml when only it exists", func(t *testing.T) {
-		dir := t.TempDir()
-		want := filepath.Join(dir, "config.yml")
-		require.NoError(t, os.WriteFile(want, []byte("a: 1"), 0644))
-
-		got, err := defaultPathInDir(dir)
-		require.NoError(t, err)
-		assert.Equal(t, want, got)
-	})
-
-	t.Run("errors when neither exists and names both paths", func(t *testing.T) {
-		dir := t.TempDir()
-		got, err := defaultPathInDir(dir)
-		assert.Empty(t, got)
-		require.Error(t, err)
-		assert.Contains(t, err.Error(), filepath.Join(dir, "config.yaml"))
-		assert.Contains(t, err.Error(), filepath.Join(dir, "config.yml"))
-	})
-}
-
-func TestDefaultPath(t *testing.T) {
-	got, err := DefaultPath()
-	if err != nil {
-		ex, exErr := os.Executable()
-		require.NoError(t, exErr)
-		assert.Contains(t, err.Error(), filepath.Dir(ex))
-		return
-	}
-	ex, err := os.Executable()
-	require.NoError(t, err)
-	assert.Equal(t, filepath.Dir(ex), filepath.Dir(got))
-	assert.Contains(t, []string{"config.yaml", "config.yml"}, filepath.Base(got))
-}

connection_manager.go

@@ -136,6 +136,14 @@ func (cm *connectionManager) getAndResetTrafficCheck(h *HostInfo, now time.Time)
 	return in, out
 }
 
+// AddTrafficWatch must be called for every new HostInfo.
+// We will continue to monitor the HostInfo until the tunnel is dropped.
+func (cm *connectionManager) AddTrafficWatch(h *HostInfo) {
+	if h.out.Swap(true) == false {
+		cm.trafficTimer.Add(h.localIndexId, cm.checkInterval)
+	}
+}
+
 func (cm *connectionManager) Start(ctx context.Context) {
 	clockSource := time.NewTicker(cm.trafficTimer.t.tickDuration)
 	defer clockSource.Stop()
@@ -298,8 +306,8 @@ func (cm *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo
 		} else {
 			cm.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, make([]byte, 12), make([]byte, mtu))
 			cm.l.Info("send CreateRelayRequest",
-				"relayFrom", relayFrom,
-				"relayTo", relayTo,
+				"relayFrom", req.RelayFromAddr,
+				"relayTo", req.RelayToAddr,
 				"initiatorRelayIndex", req.InitiatorRelayIndex,
 				"responderRelayIndex", req.ResponderRelayIndex,
 				"vpnAddrs", newhostinfo.vpnAddrs,

dns_server.go

@@ -11,21 +11,19 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"github.com/gaissmai/bart"
 	"github.com/miekg/dns"
 	"github.com/slackhq/nebula/config"
 )
 
 type dnsServer struct {
 	sync.RWMutex
-	l       *slog.Logger
-	ctx     context.Context
-	dnsMap4 map[string]netip.Addr
-	dnsMap6 map[string]netip.Addr
-	hostMap *HostMap
-	pki     *PKI
-
-	// selfHost is the cached FQDN we last seeded for ourselves
-	selfHost string
+	l               *slog.Logger
+	ctx             context.Context
+	dnsMap4         map[string]netip.Addr
+	dnsMap6         map[string]netip.Addr
+	hostMap         *HostMap
+	myVpnAddrsTable *bart.Lite
 
 	mux *dns.ServeMux
 
@@ -57,14 +55,14 @@ type dnsServer struct {
 // they no-op when DNS isn't enabled. Each Start invocation owns a ctx-cancel
 // watcher that tears the listener down on nebula shutdown. The returned
 // pointer is always non-nil, even on error.
-func newDnsServerFromConfig(ctx context.Context, l *slog.Logger, pki *PKI, hostMap *HostMap, c *config.C) (*dnsServer, error) {
+func newDnsServerFromConfig(ctx context.Context, l *slog.Logger, cs *CertState, hostMap *HostMap, c *config.C) (*dnsServer, error) {
 	ds := &dnsServer{
-		l:       l,
-		ctx:     ctx,
-		dnsMap4: make(map[string]netip.Addr),
-		dnsMap6: make(map[string]netip.Addr),
-		hostMap: hostMap,
-		pki:     pki,
+		l:               l,
+		ctx:             ctx,
+		dnsMap4:         make(map[string]netip.Addr),
+		dnsMap6:         make(map[string]netip.Addr),
+		hostMap:         hostMap,
+		myVpnAddrsTable: cs.myVpnAddrsTable,
 	}
 	ds.mux = dns.NewServeMux()
 	ds.mux.HandleFunc(".", ds.handleDnsRequest)
@@ -78,7 +76,6 @@ func newDnsServerFromConfig(ctx context.Context, l *slog.Logger, pki *PKI, hostM
 	if err := ds.reload(c, true); err != nil {
 		return ds, err
 	}
-	ds.seedSelf()
 	return ds, nil
 }
 
@@ -116,7 +113,7 @@ func (d *dnsServer) reload(c *config.C, initial bool) error {
 			d.Stop()
 		}
 		// Drop any records that accumulated while enabled; a later re-enable
-		// will repopulate from fresh handshakes and a fresh seedSelf.
+		// will repopulate from fresh handshakes.
 		d.clearRecords()
 		return nil
 	}
@@ -124,14 +121,17 @@ func (d *dnsServer) reload(c *config.C, initial bool) error {
 	if running == nil {
 		// Was disabled (or never started); bring it up now.
 		go d.Start()
-	} else if !sameAddr {
-		d.shutdownServer(running, runningStarted, "reload")
-		// Old Start goroutine has now exited; bring up a fresh listener on the new address.
-		go d.Start()
+		return nil
 	}
 
-	// Refresh the self entry every enabled reload so cert renewals that change our name or VPN addresses are picked up.
-	d.seedSelf()
+	if sameAddr {
+		return nil
+	}
+
+	d.shutdownServer(running, runningStarted, "reload")
+	// Old Start goroutine has now exited; bring up a fresh listener on the
+	// new address.
+	go d.Start()
 	return nil
 }
 
@@ -249,20 +249,6 @@ func (d *dnsServer) QueryCert(data string) string {
 		return ""
 	}
 
-	// The hostmap only ever contains peers we have handshaked with, so it never carries an entry for ourselves.
-	// Answer self lookups straight from the local cert state.
-	if cs := d.certState(); cs != nil && cs.myVpnAddrsTable != nil && cs.myVpnAddrsTable.Contains(ip) {
-		c := cs.GetDefaultCertificate()
-		if c == nil {
-			return ""
-		}
-		b, err := c.MarshalJSON()
-		if err != nil {
-			return ""
-		}
-		return string(b)
-	}
-
 	hostinfo := d.hostMap.QueryVpnAddr(ip)
 	if hostinfo == nil {
 		return ""
@@ -280,60 +266,12 @@ func (d *dnsServer) QueryCert(data string) string {
 	return string(b)
 }
 
-// clearRecords drops all DNS records, including the self entry.
+// clearRecords drops all DNS records.
 func (d *dnsServer) clearRecords() {
 	d.Lock()
 	defer d.Unlock()
 	clear(d.dnsMap4)
 	clear(d.dnsMap6)
-	d.selfHost = ""
-}
-
-// seedSelf inserts (or refreshes) a record for our own cert name pointing at our VPN addresses,
-// so a single-lighthouse network can resolve the lighthouse's own hostname without the two-process workaround.
-func (d *dnsServer) seedSelf() {
-	if !d.enabled.Load() {
-		return
-	}
-	cs := d.certState()
-	if cs == nil {
-		return
-	}
-	c := cs.GetDefaultCertificate()
-	if c == nil {
-		return
-	}
-	newHost := strings.ToLower(c.Name()) + "."
-
-	d.Lock()
-	defer d.Unlock()
-	if d.selfHost != "" && d.selfHost != newHost {
-		delete(d.dnsMap4, d.selfHost)
-		delete(d.dnsMap6, d.selfHost)
-	}
-	d.selfHost = newHost
-	delete(d.dnsMap4, newHost)
-	delete(d.dnsMap6, newHost)
-	haveV4, haveV6 := false, false
-	for _, addr := range cs.myVpnAddrs {
-		if addr.Is4() && !haveV4 {
-			d.dnsMap4[newHost] = addr
-			haveV4 = true
-		} else if addr.Is6() && !haveV6 {
-			d.dnsMap6[newHost] = addr
-			haveV6 = true
-		}
-		if haveV4 && haveV6 {
-			break
-		}
-	}
-}
-
-func (d *dnsServer) certState() *CertState {
-	if d.pki == nil {
-		return nil
-	}
-	return d.pki.getCertState()
 }
 
 // Add adds the first IPv4 and IPv6 address that appears in `addresses` as the record for `host`
@@ -371,12 +309,8 @@ func (d *dnsServer) isSelfNebulaOrLocalhost(addr string) bool {
 		return true
 	}
 
-	cs := d.certState()
-	if cs == nil || cs.myVpnAddrsTable == nil {
-		return false
-	}
 	//if we found it in this table, it's good
-	return cs.myVpnAddrsTable.Contains(b)
+	return d.myVpnAddrsTable.Contains(b)
 }
 
 func (d *dnsServer) parseQuery(m *dns.Msg, w dns.ResponseWriter) {

dns_server_test.go

@@ -9,10 +9,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/gaissmai/bart"
 	"github.com/miekg/dns"
-	"github.com/slackhq/nebula/cert"
-	"github.com/slackhq/nebula/cert_test"
 	"github.com/slackhq/nebula/config"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -279,92 +276,6 @@ func TestDnsServer_Stop_beforeBind_doesNotHang(t *testing.T) {
 	}
 }
 
-// newTestPKI builds a minimal *PKI with a single v1 cert whose name and
-// VPN addresses are caller-provided, suitable for exercising seedSelf and
-// QueryCert self handling.
-func newTestPKI(t *testing.T, name string, addrs []netip.Addr) *PKI {
-	t.Helper()
-	networks := make([]netip.Prefix, 0, len(addrs))
-	for _, a := range addrs {
-		bits := 32
-		if a.Is6() {
-			bits = 128
-		}
-		networks = append(networks, netip.PrefixFrom(a, bits))
-	}
-	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Time{}, time.Time{}, nil, nil, nil)
-	c, _, _, _ := cert_test.NewTestCert(cert.Version2, cert.Curve_CURVE25519, ca, caKey, name, time.Time{}, time.Time{}, networks, nil, nil)
-
-	addrsTable := new(bart.Lite)
-	for _, a := range addrs {
-		addrsTable.Insert(netip.PrefixFrom(a, a.BitLen()))
-	}
-
-	cs := &CertState{
-		v2Cert:            c,
-		initiatingVersion: cert.Version2,
-		myVpnAddrs:        addrs,
-		myVpnAddrsTable:   addrsTable,
-	}
-	pki := &PKI{}
-	pki.cs.Store(cs)
-	return pki
-}
-
-func TestDnsServer_seedSelf_addsOwnRecord(t *testing.T) {
-	ds, c := newTestDnsServer(t)
-	myV4 := netip.MustParseAddr("10.0.0.1")
-	myV6 := netip.MustParseAddr("fd00::1")
-	ds.pki = newTestPKI(t, "lighthouse", []netip.Addr{myV4, myV6})
-	setDnsConfig(c, "127.0.0.1", "0", true, true)
-	require.NoError(t, ds.reload(c, true))
-
-	ds.seedSelf()
-	got4, exists := ds.Query(dns.TypeA, "lighthouse.")
-	assert.True(t, exists)
-	assert.Equal(t, myV4, got4)
-	got6, exists := ds.Query(dns.TypeAAAA, "lighthouse.")
-	assert.True(t, exists)
-	assert.Equal(t, myV6, got6)
-}
-
-func TestDnsServer_seedSelf_disabled_noOp(t *testing.T) {
-	ds, c := newTestDnsServer(t)
-	ds.pki = newTestPKI(t, "lighthouse", []netip.Addr{netip.MustParseAddr("10.0.0.1")})
-	setDnsConfig(c, "127.0.0.1", "0", true, false)
-	require.NoError(t, ds.reload(c, true))
-
-	ds.seedSelf()
-	_, exists := ds.Query(dns.TypeA, "lighthouse.")
-	assert.False(t, exists)
-}
-
-func TestDnsServer_clearRecords_dropsSelfHost(t *testing.T) {
-	ds, c := newTestDnsServer(t)
-	ds.pki = newTestPKI(t, "lighthouse", []netip.Addr{netip.MustParseAddr("10.0.0.1")})
-	setDnsConfig(c, "127.0.0.1", "0", true, true)
-	require.NoError(t, ds.reload(c, true))
-	ds.seedSelf()
-	require.NotEmpty(t, ds.selfHost)
-
-	ds.clearRecords()
-	assert.Empty(t, ds.selfHost)
-	_, exists := ds.Query(dns.TypeA, "lighthouse.")
-	assert.False(t, exists)
-}
-
-func TestDnsServer_QueryCert_returnsOwnCert(t *testing.T) {
-	ds, _ := newTestDnsServer(t)
-	myV4 := netip.MustParseAddr("10.0.0.1")
-	ds.pki = newTestPKI(t, "lighthouse", []netip.Addr{myV4})
-
-	got := ds.QueryCert(myV4.String() + ".")
-	assert.NotEmpty(t, got, "TXT lookup of our own VPN address should return our cert")
-
-	other := netip.MustParseAddr("10.0.0.99")
-	assert.Empty(t, ds.QueryCert(other.String()+"."), "unknown peer IP should return nothing")
-}
-
 func TestDnsServer_reload_disable_stopsRunningServer(t *testing.T) {
 	port := freeUDPPort(t)
 	ds, c := newTestDnsServer(t)

docker/Dockerfile

@@ -1,16 +1,6 @@
 FROM gcr.io/distroless/static:latest
 
 ARG TARGETOS TARGETARCH
-
-ARG VERSION=dev
-ARG REVISION=unknown
-LABEL org.opencontainers.image.title="nebula" \
-      org.opencontainers.image.description="A scalable overlay networking tool with a focus on performance, simplicity and security" \
-      org.opencontainers.image.vendor="Nebula OSS" \
-      org.opencontainers.image.source="https://github.com/slackhq/nebula" \
-      org.opencontainers.image.version="${VERSION}" \
-      org.opencontainers.image.revision="${REVISION}"
-
 COPY build/$TARGETOS-$TARGETARCH/nebula /nebula
 COPY build/$TARGETOS-$TARGETARCH/nebula-cert /nebula-cert
 

e2e/helpers_test.go

@@ -4,15 +4,13 @@
 package e2e
 
 import (
-	"io"
+	"log/slog"
 	"net/netip"
 	"os"
 	"strings"
 	"testing"
 	"time"
 
-	"log/slog"
-
 	"dario.cat/mergo"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
@@ -382,7 +380,7 @@ func getAddrs(ns []netip.Prefix) []netip.Addr {
 func NewTestLogger() *slog.Logger {
 	v := os.Getenv("TEST_LOGS")
 	if v == "" {
-		return slog.New(slog.NewTextHandler(io.Discard, nil))
+		return slog.New(slog.DiscardHandler)
 	}
 
 	level := slog.LevelInfo

e2e/tunnels_test.go

@@ -15,7 +15,6 @@ import (
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/udp"
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 	"gopkg.in/yaml.v3"
 )
 
@@ -374,100 +373,6 @@ func TestCrossStackRelaysWork(t *testing.T) {
 	//relayControl.Stop()
 }
 
-// TestRelayReplayProtection asserts that a relay (forwarding-type) node rejects
-// replayed relay frames. A captured relay frame, re-injected with the same
-// message counter, must be dropped by the replay window rather than re-forwarded
-// to the relay target. Before the fix, handleOutsideRelayPacket authenticated the
-// frame but never advanced the replay window, so every replay was re-forwarded.
-func TestRelayReplayProtection(t *testing.T) {
-	t.Parallel()
-	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}})
-
-	myVpnV6 := myVpnIpNet[1]
-	relayVpnV4 := relayVpnIpNet[0]
-	relayVpnV6 := relayVpnIpNet[1]
-	theirVpnV6 := theirVpnIpNet[0]
-
-	// Teach me how to reach the relay and that them is reachable 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)
-
-	r := router.NewR(t, myControl, relayControl, theirControl)
-	defer r.RenderFlow()
-
-	myControl.Start()
-	relayControl.Start()
-	theirControl.Start()
-
-	// Establish the relayed tunnel in both directions so all handshakes complete.
-	t.Log("Establish the relayed tunnel")
-	myControl.InjectTunPacket(BuildTunUDPPacket(theirVpnV6.Addr(), 80, myVpnV6.Addr(), 80, []byte("Hi from me")))
-	p := r.RouteForAllUntilTxTun(theirControl)
-	assertUdpPacket(t, []byte("Hi from me"), p, myVpnV6.Addr(), theirVpnV6.Addr(), 80, 80)
-	theirControl.InjectTunPacket(BuildTunUDPPacket(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)
-
-	// Drain anything still queued on me's UDP tx so the next packet we pull is the
-	// relay frame we are about to generate.
-	for myControl.GetFromUDP(false) != nil {
-	}
-
-	// Capture a single legitimate relay frame that me transmits toward the relay.
-	t.Log("Capture a relay frame from me -> relay")
-	myControl.InjectTunPacket(BuildTunUDPPacket(theirVpnV6.Addr(), 80, myVpnV6.Addr(), 80, []byte("replay me")))
-	relayFrame := myControl.GetFromUDP(true)
-	require.Equal(t, relayUdpAddr, relayFrame.To, "captured frame should be addressed to the relay")
-	var fh header.H
-	require.NoError(t, fh.Parse(relayFrame.Data))
-	require.Equal(t, header.Message, fh.Type)
-	require.Equal(t, header.MessageRelay, fh.Subtype)
-
-	// drainForwards counts relay frames the relay forwards toward them within the
-	// settle window. We match on destination + (Message, MessageRelay) so the
-	// relay's own direct traffic to them can't be miscounted.
-	drainForwards := func(settle time.Duration) int {
-		ch := relayControl.GetUDPTxChan()
-		count := 0
-		for {
-			select {
-			case pkt := <-ch:
-				var ph header.H
-				if pkt.To == theirUdpAddr && ph.Parse(pkt.Data) == nil &&
-					ph.Type == header.Message && ph.Subtype == header.MessageRelay {
-					count++
-				}
-				pkt.Release()
-			case <-time.After(settle):
-				return count
-			}
-		}
-	}
-
-	// First delivery of the captured frame: the relay should forward it once.
-	t.Log("Deliver the captured frame once; relay forwards it to them")
-	relayControl.InjectUDPPacket(relayFrame)
-	require.Equal(t, 1, drainForwards(200*time.Millisecond), "relay should forward the first, legitimate copy")
-
-	// Replay the exact same frame several times. A correct replay window rejects
-	// these duplicates so the relay forwards none of them.
-	t.Log("Replay the captured frame; relay must drop the duplicates")
-	const replays = 3
-	for i := 0; i < replays; i++ {
-		relayControl.InjectUDPPacket(relayFrame)
-	}
-	forwarded := drainForwards(200 * time.Millisecond)
-	assert.Equal(t, 0, forwarded, "relay re-forwarded %d/%d replayed relay frames; replay protection is ineffective on relay tunnels", forwarded, replays)
-
-	r.RenderHostmaps("Final hostmaps", myControl, relayControl, theirControl)
-}
-
 func TestCloseTunnelAuthenticated(t *testing.T) {
 	t.Parallel()
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})

examples/config.yml

@@ -397,7 +397,7 @@ firewall:
   #   `drop` (default): silently drop the packet.
   #   `reject`: send a reject reply.
   #     - For TCP, this will be a RST "Connection Reset" packet.
-  #     - For other protocols, this will be an ICMP "Destination unreachable: Communication administratively prohibited" packet.
+  #     - For other protocols, this will be an ICMP port unreachable packet.
   outbound_action: drop
   inbound_action: drop
 

firewall.go

@@ -58,9 +58,8 @@ type Firewall struct {
 	routableNetworks *bart.Lite
 
 	// assignedNetworks is a list of vpn networks assigned to us in the certificate.
-	assignedNetworks []netip.Prefix
-	// unsafeNetworks is the list of unsafe networks issued to us in the certificate
-	unsafeNetworks []netip.Prefix
+	assignedNetworks  []netip.Prefix
+	hasUnsafeNetworks bool
 
 	rules        string
 	rulesVersion uint16
@@ -159,9 +158,10 @@ func NewFirewall(l *slog.Logger, tcpTimeout, UDPTimeout, defaultTimeout time.Dur
 		assignedNetworks = append(assignedNetworks, network)
 	}
 
-	unsafeNetworks := c.UnsafeNetworks()
-	for _, n := range unsafeNetworks {
+	hasUnsafeNetworks := false
+	for _, n := range c.UnsafeNetworks() {
 		routableNetworks.Insert(n)
+		hasUnsafeNetworks = true
 	}
 
 	return &Firewall{
@@ -169,15 +169,15 @@ func NewFirewall(l *slog.Logger, tcpTimeout, UDPTimeout, defaultTimeout time.Dur
 			Conns:      make(map[firewall.Packet]*conn),
 			TimerWheel: NewTimerWheel[firewall.Packet](tmin, tmax),
 		},
-		InRules:          newFirewallTable(),
-		OutRules:         newFirewallTable(),
-		TCPTimeout:       tcpTimeout,
-		UDPTimeout:       UDPTimeout,
-		DefaultTimeout:   defaultTimeout,
-		routableNetworks: routableNetworks,
-		assignedNetworks: assignedNetworks,
-		unsafeNetworks:   unsafeNetworks,
-		l:                l,
+		InRules:           newFirewallTable(),
+		OutRules:          newFirewallTable(),
+		TCPTimeout:        tcpTimeout,
+		UDPTimeout:        UDPTimeout,
+		DefaultTimeout:    defaultTimeout,
+		routableNetworks:  routableNetworks,
+		assignedNetworks:  assignedNetworks,
+		hasUnsafeNetworks: hasUnsafeNetworks,
+		l:                 l,
 
 		incomingMetrics: firewallMetrics{
 			droppedLocalAddr:  metrics.GetOrRegisterCounter("firewall.incoming.dropped.local_addr", nil),
@@ -897,7 +897,7 @@ func (flc *firewallLocalCIDR) addRule(f *Firewall, localCidr string) error {
 	}
 
 	if localCidr == "" {
-		if len(f.unsafeNetworks) == 0 || f.defaultLocalCIDRAny {
+		if !f.hasUnsafeNetworks || f.defaultLocalCIDRAny {
 			flc.Any = true
 			return nil
 		}
@@ -1055,6 +1055,7 @@ func (r *rule) sanity() error {
 }
 
 func parsePort(s string) (int32, int32, error) {
+	var err error
 	const notAPort int32 = -2
 	if s == "any" {
 		return firewall.PortAny, firewall.PortAny, nil
@@ -1063,11 +1064,11 @@ func parsePort(s string) (int32, int32, error) {
 		return firewall.PortFragment, firewall.PortFragment, nil
 	}
 	if !strings.Contains(s, `-`) {
-		rPort, err := parsePortValue("", s)
+		rPort, err := strconv.Atoi(s)
 		if err != nil {
-			return notAPort, notAPort, err
+			return notAPort, notAPort, fmt.Errorf("was not a number; `%s`", s)
 		}
-		return rPort, rPort, nil
+		return int32(rPort), int32(rPort), nil
 	}
 
 	sPorts := strings.SplitN(s, `-`, 2)
@@ -1078,40 +1079,22 @@ func parsePort(s string) (int32, int32, error) {
 		return notAPort, notAPort, fmt.Errorf("appears to be a range but could not be parsed; `%s`", s)
 	}
 
-	startPort, err := parsePortValue("beginning range ", sPorts[0])
+	rStartPort, err := strconv.Atoi(sPorts[0])
 	if err != nil {
-		return notAPort, notAPort, err
+		return notAPort, notAPort, fmt.Errorf("beginning range was not a number; `%s`", sPorts[0])
 	}
 
-	endPort, err := parsePortValue("ending range ", sPorts[1])
+	rEndPort, err := strconv.Atoi(sPorts[1])
 	if err != nil {
-		return notAPort, notAPort, err
+		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
 }
-
-// parsePortValue accepts a base-10 decimal in [0, 65535] and returns it
-// widened to int32. Using strconv.ParseUint with bitSize 16 rejects
-// negative input, out-of-range input (>65535), and any non-decimal byte
-// by construction, so the int32 widening that follows is provably safe
-// and cannot collide with firewall.PortAny (0) or firewall.PortFragment
-// (-1) via integer truncation.
-//
-// prefix is prepended to both error messages so callers can disambiguate
-// the single-port path (prefix="") from the range bounds (prefix="beginning
-// range " / "ending range "), preserving the historical error strings.
-func parsePortValue(prefix, s string) (int32, error) {
-	n, err := strconv.ParseUint(s, 10, 16)
-	if err == nil {
-		return int32(n), nil
-	}
-	if errors.Is(err, strconv.ErrRange) {
-		return 0, fmt.Errorf("%sout of range [0,65535]; `%s`", prefix, s)
-	}
-	return 0, fmt.Errorf("%swas not a number; `%s`", prefix, s)
-}

firewall_test.go

@@ -1029,75 +1029,6 @@ func Test_parsePort(t *testing.T) {
 	require.NoError(t, err)
 }
 
-// Test_parsePort_invalid covers inputs that must error. The named bug is
-// that int32(strconv.Atoi("4294967296")) truncates to 0 == firewall.PortAny,
-// silently turning a typo into a match-all-ports rule; the rest are
-// representative syntax/range probes.
-func Test_parsePort_invalid(t *testing.T) {
-	tests := []struct {
-		name            string
-		input           string
-		wantErrContains string
-	}{
-		// Numeric overflow (the named bug + boundary).
-		{"named bug: 2^32 truncates to PortAny", "4294967296", "out of range"},
-		{"just above max real port", "65536", "out of range"},
-
-		// Negatives route through the range branch and hit the empty-half
-		// guard; included as defense in depth so a future refactor cannot
-		// accidentally reach the int32 cast.
-		{"negative", "-1", "could not be parsed"},
-
-		// Syntax probes.
-		{"NUL between digits", "4\x002", "was not a number"},
-		{"hex notation", "0x10", "was not a number"},
-		{"scientific notation", "1e3", "was not a number"},
-		{"leading whitespace", " 42", "was not a number"},
-		{"fullwidth digits", "４２", "was not a number"},
-
-		// Range branch.
-		{"range upper out of range", "1-65536", "ending range out of range"},
-		{"range lower out of range", "65536-65537", "beginning range out of range"},
-		{"range with negative upper", "1--1", "ending range was not a number"},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			_, _, err := parsePort(tc.input)
-			require.Error(t, err, "input %q must error", tc.input)
-			require.ErrorContains(t, err, tc.wantErrContains)
-		})
-	}
-}
-
-// Test_parsePort_valid_boundaries locks in success cases at 0, 1, and 65535
-// so a future refactor cannot regress the boundaries.
-func Test_parsePort_valid_boundaries(t *testing.T) {
-	tests := []struct {
-		name      string
-		input     string
-		wantStart int32
-		wantEnd   int32
-	}{
-		{"zero is PortAny", "0", 0, 0},
-		{"min real port", "1", 1, 1},
-		{"max real port", "65535", 65535, 65535},
-		{"range zero to max forces end to zero", "0-65535", 0, 0},
-		{"range max to max", "65535-65535", 65535, 65535},
-		{"range one to max", "1-65535", 1, 65535},
-		{"range with whitespace inside", " 1 - 2    ", 1, 2},
-	}
-
-	for _, tc := range tests {
-		t.Run(tc.name, func(t *testing.T) {
-			s, e, err := parsePort(tc.input)
-			require.NoError(t, err)
-			assert.Equal(t, tc.wantStart, s, "start port")
-			assert.Equal(t, tc.wantEnd, e, "end port")
-		})
-	}
-}
-
 func TestNewFirewallFromConfig(t *testing.T) {
 	l := test.NewLogger()
 	// Test a bad rule definition

go.mod

@@ -9,7 +9,7 @@ require (
 	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 v0.26.1
 	github.com/gogo/protobuf v1.3.2
 	github.com/google/gopacket v1.1.19
 	github.com/kardianos/service v1.2.4
@@ -24,12 +24,12 @@ require (
 	github.com/vishvananda/netlink v1.3.1
 	go.uber.org/goleak v1.3.0
 	go.yaml.in/yaml/v3 v3.0.4
-	golang.org/x/crypto v0.53.0
+	golang.org/x/crypto v0.50.0
 	golang.org/x/exp v0.0.0-20230725093048-515e97ebf090
-	golang.org/x/net v0.56.0
-	golang.org/x/sync v0.21.0
-	golang.org/x/sys v0.46.0
-	golang.org/x/term v0.44.0
+	golang.org/x/net v0.53.0
+	golang.org/x/sync v0.20.0
+	golang.org/x/sys v0.43.0
+	golang.org/x/term v0.42.0
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard v0.0.0-20230325221338-052af4a8072b
 	golang.zx2c4.com/wireguard/windows v0.6.1

go.sum

@@ -26,8 +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 v0.28.0 h1:89yZLo8NmyqD0RYgJ3QO9HhqqGGw+oWhf90cZm69Lko=
-github.com/gaissmai/bart v0.28.0/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
+github.com/gaissmai/bart v0.26.1 h1:+w4rnLGNlA2GDVn382Tfe3jOsK5vOr5n4KmigJ9lbTo=
+github.com/gaissmai/bart v0.26.1/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=
@@ -162,8 +162,8 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACk
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
-golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
-golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
+golang.org/x/crypto v0.50.0 h1:zO47/JPrL6vsNkINmLoo/PH1gcxpls50DNogFvB5ZGI=
+golang.org/x/crypto v0.50.0/go.mod h1:3muZ7vA7PBCE6xgPX7nkzzjiUq87kRItoJQM1Yo8S+Q=
 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=
@@ -182,8 +182,8 @@ golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.56.0 h1:Rw8j/hFzGvJUZwNBXnAtf5sVDVt+65SK2C7IxCxZt5o=
-golang.org/x/net v0.56.0/go.mod h1:D3Ku6r+V6JROoZK144D2XfMHFcMq/0zSfLelVTCFKec=
+golang.org/x/net v0.53.0 h1:d+qAbo5L0orcWAr0a9JweQpjXF19LMXJE8Ey7hwOdUA=
+golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -191,8 +191,8 @@ golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -208,11 +208,11 @@ golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
-golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sys v0.43.0 h1:Rlag2XtaFTxp19wS8MXlJwTvoh8ArU6ezoyFsMyCTNI=
+golang.org/x/sys v0.43.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.44.0 h1:0rLvDRCtNj0gZkyIXhCyOb2OAzEhLVqc4B+hrsBhrmc=
-golang.org/x/term v0.44.0/go.mod h1:7ze4MdzUzLXpSAoFP1H0bOI9aXDqveSvatT5vKcFh2Y=
+golang.org/x/term v0.42.0 h1:UiKe+zDFmJobeJ5ggPwOshJIVt6/Ft0rcfrXZDLWAWY=
+golang.org/x/term v0.42.0/go.mod h1:Dq/D+snpsbazcBG5+F9Q1n2rXV8Ma+71xEjTRufARgY=
 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=

handshake/errors.go

@@ -13,7 +13,6 @@ var (
 	ErrUnknownSubtype          = errors.New("unknown handshake subtype")
 	ErrMissingContent          = errors.New("expected handshake content but message was empty")
 	ErrUnexpectedContent       = errors.New("received unexpected handshake content")
-	ErrInvalidRemoteIndex      = errors.New("peer sent an invalid index in handshake payload")
 	ErrIndexAllocation         = errors.New("failed to allocate local index")
 	ErrNoCredential            = errors.New("no handshake credential available for cert version")
 	ErrAsymmetricCipherKeys    = errors.New("noise produced only one cipher key")

handshake/machine.go

@@ -312,19 +312,11 @@ func (m *Machine) processPayload(msg []byte, flags msgFlags) error {
 
 	// Process payload
 	if flags.expectsPayload {
-		var remoteIndex uint32
 		if m.result.Initiator {
-			remoteIndex = payload.ResponderIndex
+			m.result.RemoteIndex = payload.ResponderIndex
 		} else {
-			remoteIndex = payload.InitiatorIndex
+			m.result.RemoteIndex = payload.InitiatorIndex
 		}
-		// The payload presence check above can be satisfied by Time alone, so a payload
-		// could still carry a zero index here. We need to reject it.
-		if remoteIndex == 0 {
-			m.failed = true
-			return ErrInvalidRemoteIndex
-		}
-		m.result.RemoteIndex = remoteIndex
 		m.result.HandshakeTime = payload.Time
 		m.payloadSet = true
 	}

handshake/machine_test.go

@@ -229,24 +229,6 @@ func TestMachineProcessPayload(t *testing.T) {
 		require.ErrorIs(t, err, ErrUnexpectedContent)
 		assert.True(t, m.Failed())
 	})
-
-	t.Run("zero initiator index on responder is fatal", func(t *testing.T) {
-		m := newTestMachine(t, cs, v, false, 100)
-		bytes := MarshalPayload(nil, Payload{InitiatorIndex: 0, Time: 1})
-		err := m.processPayload(bytes, msgFlags{expectsPayload: true})
-		require.ErrorIs(t, err, ErrInvalidRemoteIndex)
-		assert.True(t, m.Failed())
-		assert.Zero(t, m.result.RemoteIndex)
-	})
-
-	t.Run("zero responder index on initiator is fatal", func(t *testing.T) {
-		m := newTestMachine(t, cs, v, true, 100)
-		bytes := MarshalPayload(nil, Payload{InitiatorIndex: 100, ResponderIndex: 0, Time: 1})
-		err := m.processPayload(bytes, msgFlags{expectsPayload: true})
-		require.ErrorIs(t, err, ErrInvalidRemoteIndex)
-		assert.True(t, m.Failed())
-		assert.Zero(t, m.result.RemoteIndex)
-	})
 }
 
 // TestMachineRequireComplete checks the fail-on-incomplete-handshake path

handshake_manager.go

@@ -83,7 +83,6 @@ type HandshakeHostInfo struct {
 	initiatingVersionOverride cert.Version     // Should we use a non-default cert version for this handshake?
 	counter                   int64            // How many attempts have we made so far
 	lastRemotes               []netip.AddrPort // Remotes that we sent to during the previous attempt
-	lastRelays                []netip.Addr     // Relays we attempted to use during the previous attempt
 	packetStore               []*cachedPacket  // A set of packets to be transmitted once the handshake completes
 
 	hostinfo *HostInfo
@@ -218,6 +217,7 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 		fields := []any{
 			"udpAddrs", hh.hostinfo.remotes.CopyAddrs(hm.mainHostMap.GetPreferredRanges()),
 			"initiatorIndex", hh.hostinfo.localIndexId,
+			"remoteIndex", hh.hostinfo.remoteIndexId,
 			"durationNs", time.Since(hh.startTime).Nanoseconds(),
 		}
 		// hh.machine can be nil here if buildStage0Packet never succeeded
@@ -323,7 +323,7 @@ func (hm *HandshakeManager) handleOutbound(vpnIp netip.Addr, lighthouseTriggered
 		)
 	}
 
-	hm.f.relayManager.StartRelays(hm.f, vpnIp, hh, stage0)
+	hm.f.relayManager.StartRelays(hm.f, vpnIp, hostinfo, stage0)
 
 	// If a lighthouse triggered this attempt then we are still in the timer wheel and do not need to re-add
 	if !lighthouseTriggered {
@@ -465,6 +465,7 @@ func (hm *HandshakeManager) CheckAndComplete(hostinfo *HostInfo, handshakePacket
 		// We have a collision, but this can happen since we can't control
 		// the remote ID. Just log about the situation as a note.
 		hostinfo.logger(hm.l).Info("New host shadows existing host remoteIndex",
+			"remoteIndex", hostinfo.remoteIndexId,
 			"collision", existingRemoteIndex.vpnAddrs,
 		)
 	}
@@ -487,6 +488,7 @@ func (hm *HandshakeManager) Complete(hostinfo *HostInfo, f *Interface) {
 		// We have a collision, but this can happen since we can't control
 		// the remote ID. Just log about the situation as a note.
 		hostinfo.logger(hm.l).Info("New host shadows existing host remoteIndex",
+			"remoteIndex", hostinfo.remoteIndexId,
 			"collision", existingRemoteIndex.vpnAddrs,
 		)
 	}
@@ -796,6 +798,7 @@ func (hm *HandshakeManager) beginHandshake(via ViaSender, packet []byte, h *head
 	}
 
 	hm.sendHandshakeResponse(via, response, hostinfo, false)
+	f.connectionManager.AddTrafficWatch(hostinfo)
 	hostinfo.remotes.RefreshFromHandshake(vpnAddrs)
 
 	// Don't wait for UpdateWorker
@@ -962,6 +965,7 @@ func (hm *HandshakeManager) continueHandshake(via ViaSender, hh *HandshakeHostIn
 	hostinfo.buildNetworks(f.myVpnNetworksTable, remoteCert.Certificate)
 
 	hm.Complete(hostinfo, f)
+	f.connectionManager.AddTrafficWatch(hostinfo)
 
 	if len(hh.packetStore) > 0 {
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
@@ -970,6 +974,7 @@ func (hm *HandshakeManager) continueHandshake(via ViaSender, hh *HandshakeHostIn
 		nb := make([]byte, 12, 12)
 		out := make([]byte, mtu)
 		for _, cp := range hh.packetStore {
+			//todo use a sendbatcher
 			cp.callback(cp.messageType, cp.messageSubType, hostinfo, cp.packet, nb, out)
 		}
 		f.cachedPacketMetrics.sent.Inc(int64(len(hh.packetStore)))

hostmap.go

@@ -138,9 +138,9 @@ func (rs *RelayState) InsertRelayTo(ip netip.Addr) {
 }
 
 func (rs *RelayState) CopyRelayIps() []netip.Addr {
+	ret := make([]netip.Addr, len(rs.relays))
 	rs.RLock()
 	defer rs.RUnlock()
-	ret := make([]netip.Addr, len(rs.relays))
 	copy(ret, rs.relays)
 	return ret
 }
@@ -623,11 +623,6 @@ func (hm *HostMap) unlockedAddHostInfo(hostinfo *HostInfo, f *Interface) {
 	hm.Indexes[hostinfo.localIndexId] = hostinfo
 	hm.RemoteIndexes[hostinfo.remoteIndexId] = hostinfo
 
-	hostinfo.out.Store(true)
-	if f.connectionManager != nil { // f.connectionManager is only nil in some unit tests
-		f.connectionManager.trafficTimer.Add(hostinfo.localIndexId, f.connectionManager.checkInterval)
-	}
-
 	if hm.l.Enabled(context.Background(), slog.LevelDebug) {
 		hm.l.Debug("Hostmap vpnIp added",
 			"hostMap", m{"vpnAddrs": hostinfo.vpnAddrs, "mapTotalSize": len(hm.Hosts),

inside.go

@@ -2,6 +2,7 @@ package nebula
 
 import (
 	"context"
+	"io"
 	"log/slog"
 	"net/netip"
 
@@ -9,10 +10,16 @@ import (
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/iputil"
 	"github.com/slackhq/nebula/noiseutil"
+	"github.com/slackhq/nebula/overlay/batch"
 	"github.com/slackhq/nebula/routing"
+	"github.com/slackhq/nebula/wire"
 )
 
-func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet, nb, out []byte, q int, localCache firewall.ConntrackCache) {
+func (f *Interface) consumeInsidePacket(pkt wire.TunPacket, fwPacket *firewall.Packet, nb []byte, sendBatch *batch.SendBatch, rejectBuf []byte, q int, localCache firewall.ConntrackCache) {
+	// borrowed: pkt.Bytes is owned by the originating tio.Queue and is
+	// only valid until the next Read on that queue. If you must keep
+	// the packet, use pkt.Clone() to detach it
+	packet := pkt.Bytes
 	err := newPacket(packet, false, fwPacket)
 	if err != nil {
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
@@ -37,7 +44,10 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 		// routes packets from the Nebula addr to the Nebula addr through the Nebula
 		// TUN device.
 		if immediatelyForwardToSelf {
-			_, err := f.readers[q].Write(packet)
+			err := pkt.PerSegment(func(seg []byte) error {
+				_, werr := f.readers[q].Write(seg)
+				return werr
+			})
 			if err != nil {
 				f.l.Error("Failed to forward to tun", "error", err)
 			}
@@ -53,11 +63,23 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 	}
 
 	hostinfo, ready := f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
-		hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
+		// borrowed: SegmentSuperpacket builds each segment in the kernel-supplied pkt
+		// bytes underneath. cachePacket explicitly copies its argument (handshake_manager.go cachePacket),
+		// so retaining segments past the loop is safe.
+		err := pkt.PerSegment(func(seg []byte) error {
+			hh.cachePacket(f.l, header.Message, 0, seg, f.sendMessageNow, f.cachedPacketMetrics)
+			return nil
+		})
+		if err != nil && f.l.Enabled(context.Background(), slog.LevelDebug) {
+			f.l.Debug("Failed to segment superpacket for handshake cache",
+				"error", err,
+				"vpnAddr", fwPacket.RemoteAddr,
+			)
+		}
 	})
 
 	if hostinfo == nil {
-		f.rejectInside(packet, out, q)
+		f.rejectInside(packet, rejectBuf, q)
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			f.l.Debug("dropping outbound packet, vpnAddr not in our vpn networks or in unsafe networks",
 				"vpnAddr", fwPacket.RemoteAddr,
@@ -73,10 +95,9 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 
 	dropReason := f.firewall.Drop(*fwPacket, false, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason == nil {
-		f.sendNoMetrics(header.Message, 0, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, packet, nb, out, q)
-
+		f.sendInsideMessage(hostinfo, pkt, nb, sendBatch)
 	} else {
-		f.rejectInside(packet, out, q)
+		f.rejectInside(packet, rejectBuf, q)
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			hostinfo.logger(f.l).Debug("dropping outbound packet",
 				"fwPacket", fwPacket,
@@ -86,6 +107,124 @@ func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet
 	}
 }
 
+func (f *Interface) sendInsideEncrypt(hostinfo *HostInfo, ci *ConnectionState, seg, scratch, nb []byte) []byte {
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Lock()
+	}
+	c := ci.messageCounter.Add(1)
+
+	out := header.Encode(scratch, header.Version, header.Message, 0, hostinfo.remoteIndexId, c)
+	f.connectionManager.Out(hostinfo)
+
+	out, encErr := ci.eKey.EncryptDanger(out, out, seg, c, nb)
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Unlock()
+	}
+	if encErr != nil {
+		hostinfo.logger(f.l).Error("Failed to encrypt outgoing packet",
+			"error", encErr,
+			"udpAddr", hostinfo.remote,
+			"counter", c,
+		)
+		// Skip this segment; the rest of the superpacket can still
+		// go out — TCP will retransmit anything we drop here.
+		return nil
+	}
+
+	return out
+}
+
+// sendInsideMessage encrypts a firewall-approved inside packet (or every
+// segment of a TSO/USO superpacket) into the caller's batch slot for
+// later sendmmsg flush. Segmentation is fused with encryption here so the
+// kernel-supplied superpacket bytes never get written into a separate
+// scratch arena: PerSegment builds each segment's plaintext in
+// segScratch[:segLen] in turn, and we encrypt directly into a fresh
+// SendBatch slot.
+func (f *Interface) sendInsideMessage(hostinfo *HostInfo, pkt wire.TunPacket, nb []byte, sendBatch *batch.SendBatch) {
+	ci := hostinfo.ConnectionState
+	if ci.eKey == nil {
+		return
+	}
+
+	if hostinfo.lastRebindCount != f.rebindCount {
+		//NOTE: there is an update hole if a tunnel isn't used and exactly 256 rebinds occur before the tunnel is
+		// finally used again. This tunnel would eventually be torn down and recreated if this action didn't help.
+		f.lightHouse.QueryServer(hostinfo.vpnAddrs[0])
+		hostinfo.lastRebindCount = f.rebindCount
+		if f.l.Enabled(context.Background(), slog.LevelDebug) {
+			hostinfo.logger(f.l).Debug("Lighthouse update triggered for punch due to rebind counter",
+				"vpnAddrs", hostinfo.vpnAddrs,
+			)
+		}
+	}
+
+	if !hostinfo.remote.IsValid() { //the relay path
+		//first, find our relay hostinfo:
+		var relayHostInfo *HostInfo
+		var relay *Relay
+		var err error
+		for _, relayIP := range hostinfo.relayState.CopyRelayIps() {
+			relayHostInfo, relay, err = f.hostMap.QueryVpnAddrsRelayFor(hostinfo.vpnAddrs, relayIP)
+			if err != nil {
+				hostinfo.relayState.DeleteRelay(relayIP)
+				hostinfo.logger(f.l).Info("sendNoMetrics failed to find HostInfo",
+					"relay", relayIP,
+					"error", err,
+				)
+				continue
+			}
+			break
+		}
+		if relayHostInfo == nil || relay == nil {
+			//failure already logged
+			return
+		}
+
+		err = pkt.PerSegment(func(seg []byte) error {
+			//relay header + header + plaintext + AEAD tag (16 bytes for both AES-GCM and ChaCha20-Poly1305) + relay tag
+			scratch := sendBatch.Reserve(header.Len + header.Len + len(seg) + 16 + 16)
+
+			innerPacket := f.sendInsideEncrypt(hostinfo, ci, seg, scratch[header.Len:], nb)
+			if innerPacket == nil {
+				return nil
+			}
+
+			//now we need to do a relay-encrypt:
+			toSend, err := f.prepareSendVia(relayHostInfo, relay, innerPacket, nb, scratch, true)
+			if err != nil {
+				//already logged
+				return nil
+			}
+
+			sendBatch.Commit(toSend, relayHostInfo.remote, 0)
+			return nil
+		})
+		if err != nil {
+			hostinfo.logger(f.l).Error("Failed to segment superpacket for relay send", "error", err)
+		}
+		return
+	}
+
+	err := pkt.PerSegment(func(seg []byte) error {
+		// header + plaintext + AEAD tag (16 bytes for both AES-GCM and ChaCha20-Poly1305)
+		scratch := sendBatch.Reserve(header.Len + len(seg) + 16)
+
+		out := f.sendInsideEncrypt(hostinfo, ci, seg, scratch, nb)
+		if out == nil {
+			return nil
+		}
+
+		sendBatch.Commit(out, hostinfo.remote, 0)
+		return nil
+	})
+	if err != nil {
+		hostinfo.logger(f.l).Error("Failed to segment superpacket for send",
+			"error", err,
+		)
+	}
+}
+
 func (f *Interface) rejectInside(packet []byte, out []byte, q int) {
 	if !f.firewall.InSendReject {
 		return
@@ -275,21 +414,13 @@ func (f *Interface) sendTo(t header.MessageType, st header.MessageSubType, ci *C
 	f.sendNoMetrics(t, st, ci, hostinfo, remote, p, nb, out, 0)
 }
 
-// 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.
-// via is the HostInfo through which the message is relayed.
-// ad is the plaintext data to authenticate, but not encrypt
-// nb is a buffer used to store the nonce value, re-used for performance reasons.
-// out is a buffer used to store the result of the Encrypt operation
-// q indicates which writer to use to send the packet.
-func (f *Interface) SendVia(via *HostInfo,
+func (f *Interface) prepareSendVia(via *HostInfo,
 	relay *Relay,
 	ad,
 	nb,
 	out []byte,
 	nocopy bool,
-) {
+) ([]byte, error) {
 	if noiseutil.EncryptLockNeeded {
 		// NOTE: for goboring AESGCMTLS we need to lock because of the nonce check
 		via.ConnectionState.writeLock.Lock()
@@ -311,7 +442,7 @@ func (f *Interface) SendVia(via *HostInfo,
 			"headerLen", len(out),
 			"cipherOverhead", via.ConnectionState.eKey.Overhead(),
 		)
-		return
+		return nil, io.ErrShortBuffer
 	}
 
 	// The header bytes are written to the 'out' slice; Grow the slice to hold the header and associated data payload.
@@ -331,13 +462,36 @@ func (f *Interface) SendVia(via *HostInfo,
 	}
 	if err != nil {
 		via.logger(f.l).Info("Failed to EncryptDanger in sendVia", "error", err)
+		return nil, err
+	}
+	f.connectionManager.RelayUsed(relay.LocalIndex)
+	return out, nil
+}
+
+// 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.
+// via is the HostInfo through which the message is relayed.
+// ad is the plaintext data to authenticate, but not encrypt
+// nb is a buffer used to store the nonce value, re-used for performance reasons.
+// out is a buffer used to store the result of the Encrypt operation
+// q indicates which writer to use to send the packet.
+func (f *Interface) SendVia(via *HostInfo,
+	relay *Relay,
+	ad,
+	nb,
+	out []byte,
+	nocopy bool,
+) {
+	toSend, err := f.prepareSendVia(via, relay, ad, nb, out, nocopy)
+	if err != nil {
+		via.logger(f.l).Info("Failed to prepareSendVia", "error", err)
 		return
 	}
-	err = f.writers[0].WriteTo(out, via.remote)
+	err = f.writers[0].WriteTo(toSend, via.remote)
 	if err != nil {
 		via.logger(f.l).Info("Failed to WriteTo in sendVia", "error", err)
 	}
-	f.connectionManager.RelayUsed(relay.LocalIndex)
 }
 
 func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote netip.AddrPort, p, nb, out []byte, q int) {
@@ -391,6 +545,7 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 			"error", err,
 			"udpAddr", remote,
 			"counter", c,
+			"attemptedCounter", c,
 		)
 		return
 	}

interface.go

@@ -4,22 +4,23 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/netip"
-	"slices"
 	"sync"
 	"sync/atomic"
 	"time"
 
 	"github.com/gaissmai/bart"
 	"github.com/rcrowley/go-metrics"
+	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 
-	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/firewall"
 	"github.com/slackhq/nebula/header"
 	"github.com/slackhq/nebula/overlay"
+	"github.com/slackhq/nebula/overlay/batch"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/udp"
 )
 
@@ -39,6 +40,7 @@ type InterfaceConfig struct {
 	DropLocalBroadcast bool
 	DropMulticast      bool
 	routines           int
+	batchSize          int
 	MessageMetrics     *MessageMetrics
 	version            string
 	relayManager       *relayManager
@@ -71,6 +73,7 @@ type Interface struct {
 	dropLocalBroadcast    bool
 	dropMulticast         bool
 	routines              int
+	batchSize             int
 	disconnectInvalid     atomic.Bool
 	closed                atomic.Bool
 	relayManager          *relayManager
@@ -90,8 +93,12 @@ type Interface struct {
 
 	ctx     context.Context
 	writers []udp.Conn
-	readers []io.ReadWriteCloser
-	wg      sync.WaitGroup
+	readers []tio.Queue
+	// batchers is one per tun queue, wrapping readers[i].
+	// decryptToTun sends plaintext into the batch.RxBatcher;
+	// listenOut calls its Flush at the end of each UDP recvmmsg batch.
+	batchers []batch.RxBatcher
+	wg       sync.WaitGroup
 
 	// fatalErr holds the first unexpected reader error that caused shutdown.
 	// nil means "no fatal error" (yet)
@@ -187,9 +194,11 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 		dropLocalBroadcast:    c.DropLocalBroadcast,
 		dropMulticast:         c.DropMulticast,
 		routines:              c.routines,
+		batchSize:             c.batchSize,
 		version:               c.version,
 		writers:               make([]udp.Conn, c.routines),
-		readers:               make([]io.ReadWriteCloser, c.routines),
+		readers:               make([]tio.Queue, c.routines),
+		batchers:              make([]batch.RxBatcher, c.routines),
 		myVpnNetworks:         cs.myVpnNetworks,
 		myVpnNetworksTable:    cs.myVpnNetworksTable,
 		myVpnAddrs:            cs.myVpnAddrs,
@@ -247,15 +256,17 @@ func (f *Interface) activate() error {
 	metrics.GetOrRegisterGauge("routines", nil).Update(int64(f.routines))
 
 	// Prepare n tun queues
-	var reader io.ReadWriteCloser = f.inside
 	for i := 0; i < f.routines; i++ {
 		if i > 0 {
-			reader, err = f.inside.NewMultiQueueReader()
-			if err != nil {
+			if err = f.inside.NewMultiQueueReader(); err != nil {
 				return err
 			}
 		}
-		f.readers[i] = reader
+	}
+	f.readers = f.inside.Readers()
+	for i := range f.readers {
+		arena := util.NewArena(max(f.batchSize, 1) * udp.MTU)
+		f.batchers[i] = batch.NewPassthrough(f.readers[i], f.batchSize, arena)
 	}
 
 	f.wg.Add(1) // for us to wait on Close() to return
@@ -313,14 +324,21 @@ func (f *Interface) listenOut(i int) {
 
 	ctCache := firewall.NewConntrackCacheTicker(f.ctx, f.l, f.conntrackCacheTimeout)
 	lhh := f.lightHouse.NewRequestHandler()
-	plaintext := make([]byte, udp.MTU)
 	h := &header.H{}
 	fwPacket := &firewall.Packet{}
 	nb := make([]byte, 12, 12)
 
-	err := li.ListenOut(func(fromUdpAddr netip.AddrPort, payload []byte) {
-		f.readOutsidePackets(ViaSender{UdpAddr: fromUdpAddr}, plaintext[:0], payload, h, fwPacket, lhh, nb, i, ctCache.Get())
-	})
+	listener := func(fromUdpAddr netip.AddrPort, payload []byte, meta udp.RxMeta) {
+		f.readOutsidePackets(ViaSender{UdpAddr: fromUdpAddr}, payload, h, fwPacket, lhh, nb, i, ctCache.Get())
+	}
+
+	flusher := func() {
+		if err := f.batchers[i].Flush(); err != nil {
+			f.l.Error("Failed to flush tun coalescer", "error", err)
+		}
+	}
+
+	err := li.ListenOut(listener, flusher)
 
 	if err != nil && !f.closed.Load() {
 		f.l.Error("Error while reading inbound packet, closing", "error", err)
@@ -330,28 +348,38 @@ func (f *Interface) listenOut(i int) {
 	f.l.Debug("underlay reader is done", "reader", i)
 }
 
-func (f *Interface) listenIn(reader io.ReadWriteCloser, i int) {
-	packet := make([]byte, mtu)
-	out := make([]byte, mtu)
+func (f *Interface) listenIn(reader tio.Queue, q int) {
+	packetMem := make([]byte, mtu+16) //MTU + some leading slack space for platforms that return "bonus info"
+	// TODO get the amount of bonus info from the reader
+	packets := make([]wire.TunPacket, 1)
+	rejectBuf := make([]byte, mtu)
+	arenaSize := batch.SendBatchCap * (udp.MTU + 32)
+	sb := batch.NewSendBatch(f.writers[q], batch.SendBatchCap, util.NewArena(arenaSize))
 	fwPacket := &firewall.Packet{}
 	nb := make([]byte, 12, 12)
 
 	conntrackCache := firewall.NewConntrackCacheTicker(f.ctx, f.l, f.conntrackCacheTimeout)
 
 	for {
-		n, err := reader.Read(packet)
+		n, err := reader.Read(packets, packetMem)
 		if err != nil {
 			if !f.closed.Load() {
-				f.l.Error("Error while reading outbound packet, closing", "error", err, "reader", i)
+				f.l.Error("Error while reading outbound packet, closing", "error", err, "reader", q)
 				f.onFatal(err)
 			}
 			break
 		}
 
-		f.consumeInsidePacket(packet[:n], fwPacket, nb, out, i, conntrackCache.Get())
+		ctCache := conntrackCache.Get()
+		for i := range n {
+			f.consumeInsidePacket(packets[i], fwPacket, nb, sb, rejectBuf, q, ctCache)
+		}
+		if err := sb.Flush(); err != nil {
+			f.l.Error("Failed to write outgoing batch", "error", err, "writer", q)
+		}
 	}
 
-	f.l.Debug("overlay reader is done", "reader", i)
+	f.l.Debug("overlay reader is done", "reader", q)
 }
 
 func (f *Interface) RegisterConfigChangeCallbacks(c *config.C) {
@@ -377,22 +405,13 @@ func (f *Interface) reloadDisconnectInvalid(c *config.C) {
 }
 
 func (f *Interface) reloadFirewall(c *config.C) {
-	cs := f.pki.getCertState()
-	curCert := cs.getCertificate(cert.Version2)
-	if curCert == nil {
-		curCert = cs.getCertificate(cert.Version1)
-	}
-
-	// The firewall builds its routableNetworks set from the certificate's UnsafeNetworks at construction.
-	// Check to see if that set has changed, and if so, rebuild the firewall.
-	certUnsafeChanged := curCert != nil && !slices.Equal(curCert.UnsafeNetworks(), f.firewall.unsafeNetworks)
-
-	if !c.HasChanged("firewall") && !certUnsafeChanged {
+	//TODO: need to trigger/detect if the certificate changed too
+	if c.HasChanged("firewall") == false {
 		f.l.Debug("No firewall config change detected")
 		return
 	}
 
-	fw, err := NewFirewallFromConfig(f.l, cs, c)
+	fw, err := NewFirewallFromConfig(f.l, f.pki.getCertState(), c)
 	if err != nil {
 		f.l.Error("Error while creating firewall during reload", "error", err)
 		return
@@ -502,34 +521,26 @@ func (f *Interface) emitStats(ctx context.Context, i time.Duration) {
 	certInitiatingVersion := metrics.GetOrRegisterGauge("certificate.initiating_version", nil)
 	certMaxVersion := metrics.GetOrRegisterGauge("certificate.max_version", nil)
 
-	emit := func() {
-		f.firewall.EmitStats()
-		f.handshakeManager.EmitStats()
-		udpStats()
-
-		certState := f.pki.getCertState()
-		defaultCrt := certState.GetDefaultCertificate()
-		certExpirationGauge.Update(int64(defaultCrt.NotAfter().Sub(time.Now()) / time.Second))
-		certInitiatingVersion.Update(int64(defaultCrt.Version()))
-
-		// Report the max certificate version we are capable of using
-		if certState.v2Cert != nil {
-			certMaxVersion.Update(int64(certState.v2Cert.Version()))
-		} else {
-			certMaxVersion.Update(int64(certState.v1Cert.Version()))
-		}
-	}
-
-	// Prime gauges so a Prometheus scrape that lands before the first tick
-	// sees real values instead of the zero defaults (issue #907).
-	emit()
-
 	for {
 		select {
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			emit()
+			f.firewall.EmitStats()
+			f.handshakeManager.EmitStats()
+			udpStats()
+
+			certState := f.pki.getCertState()
+			defaultCrt := certState.GetDefaultCertificate()
+			certExpirationGauge.Update(int64(defaultCrt.NotAfter().Sub(time.Now()) / time.Second))
+			certInitiatingVersion.Update(int64(defaultCrt.Version()))
+
+			// Report the max certificate version we are capable of using
+			if certState.v2Cert != nil {
+				certMaxVersion.Update(int64(certState.v2Cert.Version()))
+			} else {
+				certMaxVersion.Update(int64(certState.v1Cert.Version()))
+			}
 		}
 	}
 }

interface_emit_test.go

@@ -1,73 +0,0 @@
-//go:build linux || darwin
-
-package nebula
-
-import (
-	"context"
-	"net/netip"
-	"testing"
-	"time"
-
-	"github.com/rcrowley/go-metrics"
-	"github.com/slackhq/nebula/cert"
-	"github.com/slackhq/nebula/firewall"
-	"github.com/slackhq/nebula/overlay/overlaytest"
-	"github.com/slackhq/nebula/test"
-	"github.com/slackhq/nebula/udp"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// Test_emitStats_primesGauges covers issue #907: a Prometheus scrape that
-// landed before the first ticker fire used to read 0 for the cert gauges.
-// emitStats now primes the gauges before entering the ticker loop. We assert
-// the gauge is zero before the first call and non-zero after.
-func Test_emitStats_primesGauges(t *testing.T) {
-	defer metrics.DefaultRegistry.UnregisterAll()
-
-	l := test.NewLogger()
-	hostMap := newHostMap(l)
-	preferredRanges := []netip.Prefix{netip.MustParsePrefix("10.0.0.0/8")}
-	hostMap.preferredRanges.Store(&preferredRanges)
-
-	notAfter := time.Now().Add(time.Hour)
-	cs := &CertState{
-		initiatingVersion: cert.Version1,
-		privateKey:        []byte{},
-		v1Cert:            &dummyCert{version: cert.Version1, notAfter: notAfter},
-		v1Credential:      nil,
-	}
-
-	lh := newTestLighthouse()
-	ifce := &Interface{
-		hostMap:          hostMap,
-		inside:           &overlaytest.NoopTun{},
-		outside:          &udp.NoopConn{},
-		firewall:         &Firewall{Conntrack: &FirewallConntrack{Conns: map[firewall.Packet]*conn{}}},
-		lightHouse:       lh,
-		pki:              &PKI{},
-		handshakeManager: NewHandshakeManager(l, hostMap, lh, &udp.NoopConn{}, defaultHandshakeConfig),
-		l:                l,
-		// On linux, udp.NewUDPStatsEmitter indexes writers[0] and asserts to
-		// *udp.StdConn. A zero value works: getMemInfo sees a nil rawConn,
-		// returns an error, and the emitter falls through to a no-op.
-		writers: []udp.Conn{&udp.StdConn{}},
-	}
-	ifce.pki.cs.Store(cs)
-
-	ttlGauge := metrics.GetOrRegisterGauge("certificate.ttl_seconds", nil)
-	require.Zero(t, ttlGauge.Value(), "gauge should be zero before emitStats runs")
-
-	// Pre-cancel the context so emitStats returns after priming the gauges
-	// without ever reading from ticker.C. The one hour interval is just a
-	// belt-and-suspenders, the test does not expect the ticker to fire.
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-	ifce.emitStats(ctx, time.Hour)
-
-	ttl := ttlGauge.Value()
-	assert.Positive(t, ttl, "ttl gauge should be primed by emitStats before its first tick")
-	assert.LessOrEqual(t, ttl, int64(3600))
-	assert.Equal(t, int64(cert.Version1), metrics.GetOrRegisterGauge("certificate.initiating_version", nil).Value())
-	assert.Equal(t, int64(cert.Version1), metrics.GetOrRegisterGauge("certificate.max_version", nil).Value())
-}

interface_test.go

@@ -1,120 +0,0 @@
-package nebula
-
-import (
-	"net/netip"
-	"testing"
-
-	"github.com/slackhq/nebula/cert"
-	"github.com/slackhq/nebula/config"
-	"github.com/slackhq/nebula/test"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// TestReloadFirewall_CertUnsafeNetworksChanged verifies that reloadFirewall
-// rebuilds the firewall when only the certificate's UnsafeNetworks have changed,
-// even if the firewall section of the YAML has not.
-func TestReloadFirewall_CertUnsafeNetworksChanged(t *testing.T) {
-	l := test.NewLogger()
-
-	vpnNet := netip.MustParsePrefix("10.0.0.1/24")
-	initialUnsafe := []netip.Prefix{netip.MustParsePrefix("198.51.100.0/24")}
-
-	// dummyCert avoids dragging the real signing pipeline into a unit test.
-	c1 := &dummyCert{
-		version:        cert.Version2,
-		networks:       []netip.Prefix{vpnNet},
-		unsafeNetworks: initialUnsafe,
-	}
-	pki := &PKI{}
-	pki.cs.Store(&CertState{v2Cert: c1, initiatingVersion: cert.Version2})
-
-	rawYAML := `firewall:
-  outbound:
-    - port: any
-      proto: any
-      host: any
-  inbound:
-    - port: any
-      proto: any
-      host: any
-`
-	cfg := config.NewC(l)
-	require.NoError(t, cfg.LoadString(rawYAML))
-
-	fw, err := NewFirewallFromConfig(l, pki.getCertState(), cfg)
-	require.NoError(t, err)
-	require.Equal(t, initialUnsafe, fw.unsafeNetworks)
-
-	f := &Interface{
-		pki:      pki,
-		firewall: fw,
-		l:        l,
-	}
-
-	// Swap the cert with a different UnsafeNetworks set.
-	newUnsafe := []netip.Prefix{
-		netip.MustParsePrefix("198.51.100.0/24"),
-		netip.MustParsePrefix("203.0.113.0/24"),
-	}
-	c2 := &dummyCert{
-		version:        cert.Version2,
-		networks:       []netip.Prefix{vpnNet},
-		unsafeNetworks: newUnsafe,
-	}
-	pki.cs.Store(&CertState{v2Cert: c2, initiatingVersion: cert.Version2})
-
-	// Reload with the same YAML so HasChanged("firewall") reports false.
-	require.NoError(t, cfg.ReloadConfigString(rawYAML))
-	require.False(t, cfg.HasChanged("firewall"))
-
-	f.reloadFirewall(cfg)
-
-	assert.NotSame(t, fw, f.firewall, "firewall pointer should have been replaced")
-	assert.Equal(t, newUnsafe, f.firewall.unsafeNetworks)
-	assert.True(t, f.firewall.routableNetworks.Contains(netip.MustParseAddr("203.0.113.5")))
-}
-
-// TestReloadFirewall_NoChange verifies that reloadFirewall is a no-op when
-// neither the firewall config nor the cert's UnsafeNetworks have changed.
-func TestReloadFirewall_NoChange(t *testing.T) {
-	l := test.NewLogger()
-
-	vpnNet := netip.MustParsePrefix("10.0.0.1/24")
-	unsafe := []netip.Prefix{netip.MustParsePrefix("198.51.100.0/24")}
-
-	c1 := &dummyCert{
-		version:        cert.Version2,
-		networks:       []netip.Prefix{vpnNet},
-		unsafeNetworks: unsafe,
-	}
-	pki := &PKI{}
-	pki.cs.Store(&CertState{v2Cert: c1, initiatingVersion: cert.Version2})
-
-	rawYAML := `firewall:
-  outbound:
-    - port: any
-      proto: any
-      host: any
-  inbound:
-    - port: any
-      proto: any
-      host: any
-`
-	cfg := config.NewC(l)
-	require.NoError(t, cfg.LoadString(rawYAML))
-
-	fw, err := NewFirewallFromConfig(l, pki.getCertState(), cfg)
-	require.NoError(t, err)
-
-	f := &Interface{
-		pki:      pki,
-		firewall: fw,
-		l:        l,
-	}
-
-	require.NoError(t, cfg.ReloadConfigString(rawYAML))
-	f.reloadFirewall(cfg)
-
-	assert.Same(t, fw, f.firewall, "firewall should not have been replaced")
-}

iputil/packet.go

@@ -4,54 +4,26 @@ import (
 	"encoding/binary"
 
 	"golang.org/x/net/ipv4"
-	"golang.org/x/net/ipv6"
 )
 
 const (
-	// MaxIPv4RejectPacketSize is the largest IPv4 reject packet:
+	// Need 96 bytes for the largest reject packet:
 	// - 20 byte ipv4 header
 	// - 8 byte icmpv4 header
 	// - 68 byte body (60 byte max orig ipv4 header + 8 byte orig icmpv4 header)
-	maxIPv4RejectPacketSize = ipv4.HeaderLen + 8 + 60 + 8
-
-	// MaxRejectPacketSize is sized for the largest possible reject packet (IPv6):
-	// - 40 byte ipv6 header
-	// - 8 byte icmpv6 header
-	// - up to 1000 byte body (original packet, possibly truncated. We want to stay
-	//   under the MTU with Nebula overhead included)
-	maxIPv6RejectPacketSize = ipv6.HeaderLen + 8 + 1000
-
-	MaxRejectPacketSize = maxIPv6RejectPacketSize
+	MaxRejectPacketSize = ipv4.HeaderLen + 8 + 60 + 8
 )
 
 func CreateRejectPacket(packet []byte, out []byte) []byte {
-	if len(packet) < 1 {
+	if len(packet) < ipv4.HeaderLen || int(packet[0]>>4) != ipv4.Version {
 		return nil
 	}
 
-	version := int(packet[0] >> 4)
-	switch version {
-	case ipv4.Version:
-		if len(packet) < ipv4.HeaderLen {
-			return nil
-		}
-		// Do not send reject packets for non-first fragments
-		if packet[6]&0x1f != 0 || packet[7] != 0 {
-			return nil
-		}
-		switch packet[9] {
-		case 6: // tcp
-			return ipv4CreateRejectTCPPacket(packet, out)
-		default:
-			return ipv4CreateRejectICMPPacket(packet, out)
-		}
-	case ipv6.Version:
-		if len(packet) < ipv6.HeaderLen {
-			return nil
-		}
-		return ipv6CreateRejectPacket(packet, out)
+	switch packet[9] {
+	case 6: // tcp
+		return ipv4CreateRejectTCPPacket(packet, out)
 	default:
-		return nil
+		return ipv4CreateRejectICMPPacket(packet, out)
 	}
 }
 
@@ -63,16 +35,11 @@ func ipv4CreateRejectICMPPacket(packet []byte, out []byte) []byte {
 		return nil
 	}
 
-	// Do not generate ICMP errors in response to ICMP error packets
-	if packet[9] == 1 && len(packet) > ihl {
-		icmpType := packet[ihl]
-		if icmpType == 3 || icmpType == 4 || icmpType == 5 || icmpType == 11 || icmpType == 12 {
-			return nil
-		}
-	}
-
 	// ICMP reply includes original header and first 8 bytes of the packet
-	packetLen := min(len(packet), ihl+8)
+	packetLen := len(packet)
+	if packetLen > ihl+8 {
+		packetLen = ihl + 8
+	}
 
 	outLen := ipv4.HeaderLen + 8 + packetLen
 	if outLen > cap(out) {
@@ -104,14 +71,14 @@ func ipv4CreateRejectICMPPacket(packet []byte, out []byte) []byte {
 
 	// ICMP Destination Unreachable
 	icmpOut := out[ipv4.HeaderLen:]
-	icmpOut[0] = 3  // type (Destination unreachable)
-	icmpOut[1] = 13 // code (Communication administratively prohibited)
-	icmpOut[2] = 0  // checksum
-	icmpOut[3] = 0  //  .
-	icmpOut[4] = 0  // unused
-	icmpOut[5] = 0  //  .
-	icmpOut[6] = 0  //  .
-	icmpOut[7] = 0  //  .
+	icmpOut[0] = 3 // type (Destination unreachable)
+	icmpOut[1] = 3 // code (Port unreachable error)
+	icmpOut[2] = 0 // checksum
+	icmpOut[3] = 0 //  .
+	icmpOut[4] = 0 // unused
+	icmpOut[5] = 0 //  .
+	icmpOut[6] = 0 //  .
+	icmpOut[7] = 0 //  .
 
 	// Copy original IP header and first 8 bytes as body
 	copy(icmpOut[8:], packet[:packetLen])
@@ -198,193 +165,7 @@ func ipv4CreateRejectTCPPacket(packet []byte, out []byte) []byte {
 	return out
 }
 
-func ipv6CreateRejectPacket(packet []byte, out []byte) []byte {
-	proto, offset, isFragment := ipv6FindUpperProtocol(packet)
-	if isFragment {
-		return nil
-	}
-	switch proto {
-	case 6: // tcp
-		return ipv6CreateRejectTCPPacket(packet, out, offset)
-	default:
-		return ipv6CreateRejectICMPPacket(packet, out, proto, offset)
-	}
-}
-
-func ipv6CreateRejectICMPPacket(packet []byte, out []byte, proto uint8, offset int) []byte {
-	// Do not generate ICMPv6 errors in response to ICMPv6 error packets
-	if proto == 58 && len(packet) > offset {
-		icmpType := packet[offset]
-		if icmpType >= 1 && icmpType <= 4 {
-			return nil
-		}
-	}
-
-	// Include as much of the original packet as possible, up to 1000 bytes,
-	// so the response fits comfortably within any tunnel MTU.
-	packetLen := min(len(packet), 1000)
-
-	outLen := ipv6.HeaderLen + 8 + packetLen
-	if outLen > cap(out) {
-		return nil
-	}
-
-	out = out[:outLen]
-
-	// IPv6 header
-	ipHdr := out[0:ipv6.HeaderLen]
-	ipHdr[0] = ipv6.Version << 4 // version, traffic class (high bits)
-	ipHdr[1] = 0                 // traffic class (low bits), flow label (high bits)
-	ipHdr[2] = 0                 // flow label
-	ipHdr[3] = 0                 // flow label
-
-	payloadLen := uint16(outLen - ipv6.HeaderLen)
-	binary.BigEndian.PutUint16(ipHdr[4:], payloadLen) // payload length
-	ipHdr[6] = 58                                     // next header (ICMPv6)
-	ipHdr[7] = 64                                     // hop limit
-
-	// Swap dest / src IPs (each 16 bytes, src at 8, dst at 24)
-	copy(ipHdr[8:24], packet[24:40])
-	copy(ipHdr[24:40], packet[8:24])
-
-	// ICMPv6 Destination Unreachable
-	icmpOut := out[ipv6.HeaderLen:]
-	icmpOut[0] = 1 // type (Destination Unreachable)
-	icmpOut[1] = 1 // code (Communication with destination administratively prohibited)
-	icmpOut[2] = 0 // checksum
-	icmpOut[3] = 0 //  .
-	icmpOut[4] = 0 // unused
-	icmpOut[5] = 0 //  .
-	icmpOut[6] = 0 //  .
-	icmpOut[7] = 0 //  .
-
-	copy(icmpOut[8:], packet[:packetLen])
-
-	// ICMPv6 checksum uses a pseudo-header
-	csum := ipv6PseudoheaderChecksum(ipHdr[8:24], ipHdr[24:40], 58, uint32(payloadLen))
-	binary.BigEndian.PutUint16(icmpOut[2:], tcpipChecksum(icmpOut, csum))
-
-	return out
-}
-
-func ipv6CreateRejectTCPPacket(packet []byte, out []byte, offset int) []byte {
-	const tcpLen = 20
-
-	if len(packet) < offset+tcpLen {
-		return nil
-	}
-
-	outLen := ipv6.HeaderLen + tcpLen
-	if outLen > cap(out) {
-		return nil
-	}
-
-	out = out[:outLen]
-
-	// IPv6 header
-	ipHdr := out[0:ipv6.HeaderLen]
-	ipHdr[0] = ipv6.Version << 4 // version, traffic class (high bits)
-	ipHdr[1] = 0                 // traffic class (low bits), flow label (high bits)
-	ipHdr[2] = 0                 // flow label
-	ipHdr[3] = 0                 // flow label
-
-	binary.BigEndian.PutUint16(ipHdr[4:], tcpLen) // payload length
-	ipHdr[6] = 6                                  // next header (TCP)
-	ipHdr[7] = 64                                 // hop limit
-
-	// Swap dest / src IPs
-	copy(ipHdr[8:24], packet[24:40])
-	copy(ipHdr[24:40], packet[8:24])
-
-	// TCP RST
-	tcpIn := packet[offset:]
-	var ackSeq, seq uint32
-	outFlags := byte(0b00000100) // RST
-
-	inAck := tcpIn[13]&0b00010000 != 0
-	if inAck {
-		seq = binary.BigEndian.Uint32(tcpIn[8:])
-	} else {
-		inSyn := uint32((tcpIn[13] & 0b00000010) >> 1)
-		inFin := uint32(tcpIn[13] & 0b00000001)
-		ackSeq = binary.BigEndian.Uint32(tcpIn[4:]) + inSyn + inFin + uint32(len(tcpIn)) - uint32(tcpIn[12]>>4)<<2
-		outFlags |= 0b00010000 // ACK
-	}
-
-	tcpOut := out[ipv6.HeaderLen:]
-	// Swap dest / src ports
-	copy(tcpOut[0:2], tcpIn[2:4])
-	copy(tcpOut[2:4], tcpIn[0:2])
-	binary.BigEndian.PutUint32(tcpOut[4:], seq)
-	binary.BigEndian.PutUint32(tcpOut[8:], ackSeq)
-	tcpOut[12] = (tcpLen >> 2) << 4 // data offset, reserved, NS
-	tcpOut[13] = outFlags           // CWR, ECE, URG, ACK, PSH, RST, SYN, FIN
-	tcpOut[14] = 0                  // window size
-	tcpOut[15] = 0                  //  .
-	tcpOut[16] = 0                  // checksum
-	tcpOut[17] = 0                  //  .
-	tcpOut[18] = 0                  // URG Pointer
-	tcpOut[19] = 0                  //  .
-
-	// Calculate checksum with IPv6 pseudo-header
-	csum := ipv6PseudoheaderChecksum(ipHdr[8:24], ipHdr[24:40], 6, tcpLen)
-	binary.BigEndian.PutUint16(tcpOut[16:], tcpipChecksum(tcpOut, csum))
-
-	return out
-}
-
-func ipv6FindUpperProtocol(packet []byte) (nextHeader uint8, offset int, isFragment bool) {
-	nextHeader = packet[6]
-	offset = ipv6.HeaderLen
-
-	for {
-		switch nextHeader {
-		case 0, 43, 60: // Hop-by-Hop, Routing, Destination
-			if len(packet) < offset+2 {
-				return nextHeader, offset, isFragment
-			}
-			nextHeader = packet[offset]
-			offset += int(packet[offset+1]+1) << 3
-
-		case 44: // Fragment
-			if len(packet) < offset+8 {
-				return nextHeader, offset, isFragment
-			}
-			if packet[offset+2] != 0 || packet[offset+3]&0xf8 != 0 {
-				isFragment = true
-			}
-			nextHeader = packet[offset]
-			offset += 8
-
-		case 51: // AH
-			if len(packet) < offset+2 {
-				return nextHeader, offset, isFragment
-			}
-			nextHeader = packet[offset]
-			offset += int(packet[offset+1]+2) << 2
-
-		default:
-			return nextHeader, offset, isFragment
-		}
-	}
-}
-
 func CreateICMPEchoResponse(packet, out []byte) []byte {
-	if len(packet) < 1 {
-		return nil
-	}
-
-	switch packet[0] >> 4 {
-	case 4:
-		return createICMPv4EchoResponse(packet, out)
-	case 6:
-		return createICMPv6EchoResponse(packet, out)
-	default:
-		return nil
-	}
-}
-
-func createICMPv4EchoResponse(packet, out []byte) []byte {
 	// Return early if this is not a simple ICMP Echo Request
 	//TODO: make constants out of these
 	if !(len(packet) >= 28 && len(packet) <= 9001 && packet[0] == 0x45 && packet[9] == 0x01 && packet[20] == 0x08) {
@@ -418,43 +199,6 @@ func createICMPv4EchoResponse(packet, out []byte) []byte {
 	return out
 }
 
-func createICMPv6EchoResponse(packet, out []byte) []byte {
-	// IPv6 header (40 bytes) + ICMPv6 header (8 bytes minimum)
-	if len(packet) < ipv6.HeaderLen+8 || len(packet) > 9001 {
-		return nil
-	}
-
-	// Next Header must be ICMPv6 (58)
-	if packet[6] != 58 {
-		return nil
-	}
-
-	// ICMPv6 type must be Echo Request (128)
-	if packet[ipv6.HeaderLen] != 128 {
-		return nil
-	}
-
-	out = out[:len(packet)]
-	copy(out, packet)
-
-	// Swap src/dst addresses (bytes 8-23 and 24-39)
-	copy(out[8:24], packet[24:40])
-	copy(out[24:40], packet[8:24])
-
-	// Change ICMPv6 type to Echo Reply (129)
-	icmp := out[ipv6.HeaderLen:]
-	icmp[0] = 129
-	icmp[2] = 0
-	icmp[3] = 0
-
-	// ICMPv6 checksum uses a pseudo-header with src, dst, length, and next header
-	payloadLen := uint32(len(icmp))
-	csum := ipv6PseudoheaderChecksum(out[8:24], out[24:40], 58, payloadLen)
-	binary.BigEndian.PutUint16(icmp[2:], tcpipChecksum(icmp, csum))
-
-	return out
-}
-
 // calculates the TCP/IP checksum defined in rfc1071. The passed-in
 // csum is any initial checksum data that's already been computed.
 //
@@ -492,18 +236,3 @@ func ipv4PseudoheaderChecksum(src, dst []byte, proto, length uint32) (csum uint3
 	csum += length >> 16
 	return csum
 }
-
-// based on:
-// - https://github.com/google/gopacket/blob/v1.1.19/layers/tcpip.go#L37-L48
-func ipv6PseudoheaderChecksum(src, dst []byte, proto, length uint32) (csum uint32) {
-	for i := 0; i < 16; i += 2 {
-		csum += uint32(src[i]) << 8
-		csum += uint32(src[i+1])
-		csum += uint32(dst[i]) << 8
-		csum += uint32(dst[i+1])
-	}
-	csum += proto
-	csum += length & 0xffff
-	csum += length >> 16
-	return csum
-}

iputil/packet_test.go

@@ -1,13 +1,11 @@
 package iputil
 
 import (
-	"encoding/binary"
 	"net"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"golang.org/x/net/ipv4"
-	"golang.org/x/net/ipv6"
 )
 
 func Test_CreateRejectPacket(t *testing.T) {
@@ -45,7 +43,7 @@ func Test_CreateRejectPacket(t *testing.T) {
 	}
 	b = append(b, []byte{0, 3, 0, 4, 0, 0, 0, 0}...)
 
-	expectedLen = maxIPv4RejectPacketSize
+	expectedLen = MaxRejectPacketSize
 	out = make([]byte, MaxRejectPacketSize)
 	rejectPacket = CreateRejectPacket(b, out)
 	assert.NotNil(t, rejectPacket)
@@ -73,404 +71,3 @@ func Test_CreateRejectPacket(t *testing.T) {
 	assert.NotNil(t, rejectPacket)
 	assert.Len(t, rejectPacket, expectedLen)
 }
-
-func Test_CreateRejectPacket_NoFragment(t *testing.T) {
-	out := make([]byte, MaxRejectPacketSize)
-
-	// IPv4: non-zero fragment offset should not generate reject packet
-	h := ipv4.Header{
-		Len:      20,
-		Src:      net.IPv4(10, 0, 0, 1),
-		Dst:      net.IPv4(10, 0, 0, 2),
-		Protocol: 17, // UDP
-	}
-	b, err := h.Marshal()
-	if err != nil {
-		t.Fatalf("h.Marshal: %v", err)
-	}
-	b = append(b, make([]byte, 8)...)
-	// Set fragment offset to non-zero (byte 6-7, offset in 8-byte units)
-	b[6] = 0x00
-	b[7] = 0x01
-	assert.Nil(t, CreateRejectPacket(b, out))
-
-	// MF flag with zero offset (first fragment) should still generate reject
-	b[6] = 0x20 // MF flag set
-	b[7] = 0x00
-	assert.NotNil(t, CreateRejectPacket(b, out))
-
-	// Non-fragment should still generate reject packet
-	b[6] = 0x00
-	b[7] = 0x00
-	assert.NotNil(t, CreateRejectPacket(b, out))
-
-	// DF flag only (not a fragment) should still generate reject packet
-	b[6] = 0x40
-	b[7] = 0x00
-	assert.NotNil(t, CreateRejectPacket(b, out))
-}
-
-func Test_CreateRejectPacketIPv6_NoFragment(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-	out := make([]byte, MaxRejectPacketSize)
-
-	// IPv6 with Fragment header and non-zero offset should not generate reject
-	fragHeader := []byte{
-		17,   // next header: UDP
-		0,    // reserved
-		0, 9, // fragment offset=1 (shifted left 3), M=1
-		0, 0, 0, 1, // identification
-	}
-	udpPayload := make([]byte, 8)
-	payload := append(fragHeader, udpPayload...)
-	packet := makeIPv6Packet(src, dst, 44, payload) // next header 44 = Fragment
-	assert.Nil(t, CreateRejectPacket(packet, out))
-
-	// Fragment header with zero offset (first fragment) should still generate reject
-	fragHeader[2] = 0
-	fragHeader[3] = 1 // offset=0, M=1
-	payload = append(fragHeader, udpPayload...)
-	packet = makeIPv6Packet(src, dst, 44, payload)
-	assert.NotNil(t, CreateRejectPacket(packet, out))
-}
-
-func Test_CreateRejectPacket_NoICMPError(t *testing.T) {
-	out := make([]byte, MaxRejectPacketSize)
-
-	// ICMP error types should not generate reject packets
-	icmpErrorTypes := []byte{3, 4, 5, 11, 12}
-	for _, icmpType := range icmpErrorTypes {
-		h := ipv4.Header{
-			Len:      20,
-			Src:      net.IPv4(10, 0, 0, 1),
-			Dst:      net.IPv4(10, 0, 0, 2),
-			Protocol: 1, // ICMP
-		}
-
-		b, err := h.Marshal()
-		if err != nil {
-			t.Fatalf("h.Marshal: %v", err)
-		}
-		b = append(b, icmpType, 0, 0, 0, 0, 0, 0, 0)
-
-		rejectPacket := CreateRejectPacket(b, out)
-		assert.Nil(t, rejectPacket, "ICMP type %d should not generate a reject packet", icmpType)
-	}
-
-	// ICMP non-error types should still generate reject packets
-	icmpNonErrorTypes := []byte{0, 8, 13, 14}
-	for _, icmpType := range icmpNonErrorTypes {
-		h := ipv4.Header{
-			Len:      20,
-			Src:      net.IPv4(10, 0, 0, 1),
-			Dst:      net.IPv4(10, 0, 0, 2),
-			Protocol: 1, // ICMP
-		}
-
-		b, err := h.Marshal()
-		if err != nil {
-			t.Fatalf("h.Marshal: %v", err)
-		}
-		b = append(b, icmpType, 0, 0, 0, 0, 0, 0, 0)
-
-		rejectPacket := CreateRejectPacket(b, out)
-		assert.NotNil(t, rejectPacket, "ICMP type %d should generate a reject packet", icmpType)
-	}
-}
-
-func makeIPv6Packet(src, dst net.IP, nextHeader uint8, payload []byte) []byte {
-	b := make([]byte, ipv6.HeaderLen+len(payload))
-	b[0] = ipv6.Version << 4
-	binary.BigEndian.PutUint16(b[4:], uint16(len(payload)))
-	b[6] = nextHeader
-	b[7] = 64
-	copy(b[8:24], src.To16())
-	copy(b[24:40], dst.To16())
-	copy(b[ipv6.HeaderLen:], payload)
-	return b
-}
-
-func Test_CreateRejectPacketIPv6_ICMP(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-
-	// Small UDP packet: entire original included in body
-	udpPayload := make([]byte, 20)
-	udpPayload[0] = 0x00 // src port high
-	udpPayload[1] = 0x50 // src port low (80)
-	udpPayload[2] = 0x01 // dst port high
-	udpPayload[3] = 0xBB // dst port low (443)
-	packet := makeIPv6Packet(src, dst, 17, udpPayload)
-
-	out := make([]byte, MaxRejectPacketSize)
-	rejectPacket := CreateRejectPacket(packet, out)
-	assert.NotNil(t, rejectPacket)
-
-	// Small packet fits entirely: 40 (ipv6 hdr) + 8 (icmpv6 hdr) + 60 (original)
-	expectedLen := ipv6.HeaderLen + 8 + len(packet)
-	assert.Len(t, rejectPacket, expectedLen)
-
-	// Verify version
-	assert.Equal(t, byte(ipv6.Version<<4), rejectPacket[0]&0xf0)
-	// Verify next header is ICMPv6 (58)
-	assert.Equal(t, byte(58), rejectPacket[6])
-	// Verify src/dst are swapped
-	assert.Equal(t, dst.To16(), net.IP(rejectPacket[8:24]))
-	assert.Equal(t, src.To16(), net.IP(rejectPacket[24:40]))
-	// Verify ICMPv6 type=1 (Dest Unreachable), code=1 (Administratively prohibited)
-	assert.Equal(t, byte(1), rejectPacket[ipv6.HeaderLen])
-	assert.Equal(t, byte(1), rejectPacket[ipv6.HeaderLen+1])
-	// Verify entire original packet is included in body
-	assert.Equal(t, packet, rejectPacket[ipv6.HeaderLen+8:])
-
-	// Large packet: body is truncated to 1000 bytes
-	largePkt := makeIPv6Packet(src, dst, 17, make([]byte, 1200))
-	rejectPacket = CreateRejectPacket(largePkt, out)
-	assert.NotNil(t, rejectPacket)
-	assert.Len(t, rejectPacket, ipv6.HeaderLen+8+1000)
-	assert.Equal(t, largePkt[:1000], rejectPacket[ipv6.HeaderLen+8:])
-}
-
-func Test_CreateRejectPacketIPv6_TCP(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-
-	// TCP SYN packet (next header 6)
-	tcpPayload := make([]byte, 20)
-	tcpPayload[0] = 0x00                             // src port high
-	tcpPayload[1] = 0x50                             // src port low (80)
-	tcpPayload[2] = 0x01                             // dst port high
-	tcpPayload[3] = 0xBB                             // dst port low (443)
-	binary.BigEndian.PutUint32(tcpPayload[4:], 1000) // seq
-	binary.BigEndian.PutUint32(tcpPayload[8:], 0)    // ack seq
-	tcpPayload[12] = (20 >> 2) << 4                  // data offset
-	tcpPayload[13] = 0b00000010                      // SYN flag
-
-	packet := makeIPv6Packet(src, dst, 6, tcpPayload)
-
-	out := make([]byte, MaxRejectPacketSize)
-	rejectPacket := CreateRejectPacket(packet, out)
-	assert.NotNil(t, rejectPacket)
-
-	// Expected: 40 (ipv6 hdr) + 20 (tcp RST)
-	expectedLen := ipv6.HeaderLen + 20
-	assert.Len(t, rejectPacket, expectedLen)
-
-	// Verify version
-	assert.Equal(t, byte(ipv6.Version<<4), rejectPacket[0]&0xf0)
-	// Verify next header is TCP (6)
-	assert.Equal(t, byte(6), rejectPacket[6])
-	// Verify src/dst are swapped
-	assert.Equal(t, dst.To16(), net.IP(rejectPacket[8:24]))
-	assert.Equal(t, src.To16(), net.IP(rejectPacket[24:40]))
-	// Verify ports are swapped
-	tcpOut := rejectPacket[ipv6.HeaderLen:]
-	assert.Equal(t, uint16(443), binary.BigEndian.Uint16(tcpOut[0:2]))
-	assert.Equal(t, uint16(80), binary.BigEndian.Uint16(tcpOut[2:4]))
-	// RST+ACK flags (since input was SYN without ACK)
-	assert.Equal(t, byte(0b00010100), tcpOut[13])
-	// ack_seq = original seq (1000) + SYN (1) + FIN (0) + segment data (0)
-	assert.Equal(t, uint32(1001), binary.BigEndian.Uint32(tcpOut[8:]))
-}
-
-func Test_CreateRejectPacketIPv6_TCPWithACK(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-
-	// TCP packet with ACK set
-	tcpPayload := make([]byte, 20)
-	tcpPayload[0] = 0x00
-	tcpPayload[1] = 0x50
-	tcpPayload[2] = 0x01
-	tcpPayload[3] = 0xBB
-	binary.BigEndian.PutUint32(tcpPayload[4:], 1000) // seq
-	binary.BigEndian.PutUint32(tcpPayload[8:], 2000) // ack seq
-	tcpPayload[12] = (20 >> 2) << 4                  // data offset
-	tcpPayload[13] = 0b00010000                      // ACK flag
-
-	packet := makeIPv6Packet(src, dst, 6, tcpPayload)
-
-	out := make([]byte, MaxRejectPacketSize)
-	rejectPacket := CreateRejectPacket(packet, out)
-	assert.NotNil(t, rejectPacket)
-
-	tcpOut := rejectPacket[ipv6.HeaderLen:]
-	// RST only (no ACK) since input had ACK
-	assert.Equal(t, byte(0b00000100), tcpOut[13])
-	// seq = original ack_seq
-	assert.Equal(t, uint32(2000), binary.BigEndian.Uint32(tcpOut[4:]))
-}
-
-func Test_CreateRejectPacketIPv6_NoICMPError(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-	out := make([]byte, MaxRejectPacketSize)
-
-	// ICMPv6 error types (1-4) should not generate reject packets
-	for icmpType := byte(1); icmpType <= 4; icmpType++ {
-		payload := make([]byte, 8)
-		payload[0] = icmpType
-		packet := makeIPv6Packet(src, dst, 58, payload)
-
-		rejectPacket := CreateRejectPacket(packet, out)
-		assert.Nil(t, rejectPacket, "ICMPv6 type %d should not generate a reject packet", icmpType)
-	}
-
-	// ICMPv6 non-error types should still generate reject packets
-	nonErrorTypes := []byte{128, 129, 133, 134}
-	for _, icmpType := range nonErrorTypes {
-		payload := make([]byte, 8)
-		payload[0] = icmpType
-		packet := makeIPv6Packet(src, dst, 58, payload)
-
-		rejectPacket := CreateRejectPacket(packet, out)
-		assert.NotNil(t, rejectPacket, "ICMPv6 type %d should generate a reject packet", icmpType)
-	}
-}
-
-func Test_CreateRejectPacketIPv6_TooShort(t *testing.T) {
-	// Packet too short to be valid IPv6
-	out := make([]byte, MaxRejectPacketSize)
-	assert.Nil(t, CreateRejectPacket([]byte{0x60}, out))
-	assert.Nil(t, CreateRejectPacket(make([]byte, 39), out))
-}
-
-func Test_CreateRejectPacketIPv6_ExtensionHeaders(t *testing.T) {
-	src := net.ParseIP("fd00::1")
-	dst := net.ParseIP("fd00::2")
-
-	// IPv6 + Hop-by-Hop extension header + TCP
-	hopByHop := []byte{
-		6,    // next header: TCP
-		0,    // length (8 bytes total)
-		0, 0, // padding
-		0, 0, 0, 0,
-	}
-	tcpPayload := make([]byte, 20)
-	tcpPayload[0] = 0x00
-	tcpPayload[1] = 0x50
-	tcpPayload[2] = 0x01
-	tcpPayload[3] = 0xBB
-	binary.BigEndian.PutUint32(tcpPayload[4:], 1000)
-	binary.BigEndian.PutUint32(tcpPayload[8:], 2000)
-	tcpPayload[12] = (20 >> 2) << 4
-	tcpPayload[13] = 0b00010000 // ACK
-
-	payload := append(hopByHop, tcpPayload...)
-	packet := makeIPv6Packet(src, dst, 0, payload) // next header 0 = Hop-by-Hop
-
-	out := make([]byte, MaxRejectPacketSize)
-	rejectPacket := CreateRejectPacket(packet, out)
-	assert.NotNil(t, rejectPacket)
-
-	// Should produce TCP RST
-	expectedLen := ipv6.HeaderLen + 20
-	assert.Len(t, rejectPacket, expectedLen)
-	assert.Equal(t, byte(6), rejectPacket[6]) // next header is TCP
-	tcpOut := rejectPacket[ipv6.HeaderLen:]
-	assert.Equal(t, byte(0b00000100), tcpOut[13]) // RST only
-}
-
-func TestCreateICMPEchoResponse_IPv4(t *testing.T) {
-	// Build a simple IPv4 ICMP Echo Request
-	packet := make([]byte, 28)
-	packet[0] = 0x45                                   // version 4, IHL 5
-	binary.BigEndian.PutUint16(packet[2:], uint16(28)) // total length
-	packet[8] = 64                                     // TTL
-	packet[9] = 1                                      // protocol ICMP
-	copy(packet[12:16], net.IPv4(10, 0, 0, 1).To4())   // src
-	copy(packet[16:20], net.IPv4(10, 0, 0, 2).To4())   // dst
-	packet[20] = 8                                     // ICMP Echo Request
-
-	out := make([]byte, len(packet))
-	result := CreateICMPEchoResponse(packet, out)
-	assert.NotNil(t, result)
-	assert.Equal(t, byte(0x45), result[0])
-	// src/dst swapped
-	assert.Equal(t, net.IPv4(10, 0, 0, 2).To4(), net.IP(result[12:16]))
-	assert.Equal(t, net.IPv4(10, 0, 0, 1).To4(), net.IP(result[16:20]))
-	// ICMP Echo Reply
-	assert.Equal(t, byte(0), result[20])
-}
-
-func TestCreateICMPEchoResponse_IPv6(t *testing.T) {
-	src := net.ParseIP("fd00::1").To16()
-	dst := net.ParseIP("fd00::2").To16()
-
-	// Build an IPv6 ICMPv6 Echo Request packet
-	// IPv6 header (40 bytes) + ICMPv6 (8 bytes)
-	packet := make([]byte, 48)
-	packet[0] = 0x60        // version 6
-	payloadLen := uint16(8) // ICMPv6 header only
-	binary.BigEndian.PutUint16(packet[4:], payloadLen)
-	packet[6] = 58           // Next Header: ICMPv6
-	packet[7] = 64           // Hop Limit
-	copy(packet[8:24], src)  // src address
-	copy(packet[24:40], dst) // dst address
-
-	// ICMPv6 Echo Request
-	icmp := packet[40:]
-	icmp[0] = 128                           // type: Echo Request
-	icmp[1] = 0                             // code
-	binary.BigEndian.PutUint16(icmp[4:], 1) // identifier
-	binary.BigEndian.PutUint16(icmp[6:], 1) // sequence number
-
-	// Compute correct checksum for the request
-	csum := ipv6PseudoheaderChecksum(src, dst, 58, uint32(payloadLen))
-	binary.BigEndian.PutUint16(icmp[2:], tcpipChecksum(icmp, csum))
-
-	out := make([]byte, len(packet))
-	result := CreateICMPEchoResponse(packet, out)
-	assert.NotNil(t, result)
-
-	// Version should still be 6
-	assert.Equal(t, byte(6), result[0]>>4)
-	// src/dst swapped
-	assert.Equal(t, dst, net.IP(result[8:24]))
-	assert.Equal(t, src, net.IP(result[24:40]))
-	// ICMPv6 Echo Reply type
-	assert.Equal(t, byte(129), result[40])
-
-	// Verify checksum is valid (tcpipChecksum returns 0 when data+checksum is correct)
-	respIcmp := result[40:]
-	verifyCsum := ipv6PseudoheaderChecksum(result[8:24], result[24:40], 58, uint32(payloadLen))
-	assert.Equal(t, uint16(0), tcpipChecksum(respIcmp, verifyCsum))
-}
-
-func TestCreateICMPEchoResponse_IPv6_NotEchoRequest(t *testing.T) {
-	src := net.ParseIP("fd00::1").To16()
-	dst := net.ParseIP("fd00::2").To16()
-
-	packet := make([]byte, 48)
-	packet[0] = 0x60
-	binary.BigEndian.PutUint16(packet[4:], 8)
-	packet[6] = 58
-	packet[7] = 64
-	copy(packet[8:24], src)
-	copy(packet[24:40], dst)
-
-	// ICMPv6 type 1 (Destination Unreachable) - not Echo Request
-	packet[40] = 1
-
-	out := make([]byte, len(packet))
-	result := CreateICMPEchoResponse(packet, out)
-	assert.Nil(t, result)
-}
-
-func TestCreateICMPEchoResponse_IPv6_NotICMPv6(t *testing.T) {
-	src := net.ParseIP("fd00::1").To16()
-	dst := net.ParseIP("fd00::2").To16()
-
-	packet := make([]byte, 48)
-	packet[0] = 0x60
-	binary.BigEndian.PutUint16(packet[4:], 8)
-	packet[6] = 6 // TCP, not ICMPv6
-	packet[7] = 64
-	copy(packet[8:24], src)
-	copy(packet[24:40], dst)
-
-	out := make([]byte, len(packet))
-	result := CreateICMPEchoResponse(packet, out)
-	assert.Nil(t, result)
-}

lighthouse.go

@@ -272,18 +272,16 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 	//NOTE: many things will get much simpler when we combine static_host_map and lighthouse.hosts in config
 	if initial || c.HasChanged("static_host_map") || c.HasChanged("static_map.cadence") || c.HasChanged("static_map.network") || c.HasChanged("static_map.lookup_timeout") {
 		// Clean up. Entries still in the static_host_map will be re-built.
-		ourselves := lh.myVpnNetworks[0].Addr()
-		oldStaticList := lh.staticList.Load()
-		if oldStaticList != nil {
+		// Entries no longer present must have their (possible) background DNS goroutines stopped.
+		if existingStaticList := lh.staticList.Load(); existingStaticList != nil {
 			lh.RLock()
-			for staticVpnAddr := range *oldStaticList {
+			for staticVpnAddr := range *existingStaticList {
 				if am, ok := lh.addrMap[staticVpnAddr]; ok && am != nil {
-					am.ResetForOwner(ourselves)
+					am.hr.Cancel()
 				}
 			}
 			lh.RUnlock()
 		}
-
 		// Build a new list based on current config.
 		staticList := make(map[netip.Addr]struct{})
 		err := lh.loadStaticMap(c, staticList)
@@ -291,21 +289,6 @@ func (lh *LightHouse) reload(c *config.C, initial bool) error {
 			return err
 		}
 
-		// For entries removed from static_host_map, stop the DNS goroutine and drop the cached addrs.
-		// All addrs must come from the lighthouses now that it's no longer a static host.
-		if oldStaticList != nil {
-			lh.RLock()
-			for staticVpnAddr := range *oldStaticList {
-				if _, stillStatic := staticList[staticVpnAddr]; stillStatic {
-					continue
-				}
-				if am, ok := lh.addrMap[staticVpnAddr]; ok && am != nil {
-					am.ClearHostnameResults()
-				}
-			}
-			lh.RUnlock()
-		}
-
 		lh.staticList.Store(&staticList)
 		if !initial {
 			if c.HasChanged("static_host_map") {

lighthouse_test.go

@@ -303,132 +303,6 @@ func TestLighthouse_reload(t *testing.T) {
 	require.NoError(t, err)
 }
 
-// TestLighthouse_reloadStaticHostMap verifies that reloading static_host_map applies the new
-// config rather than appending to it. See issue #718.
-func TestLighthouse_reloadStaticHostMap(t *testing.T) {
-	l := test.NewLogger()
-	c := config.NewC(l)
-	c.Settings["lighthouse"] = map[string]any{"am_lighthouse": true}
-	c.Settings["listen"] = map[string]any{"port": 4242}
-	c.Settings["static_host_map"] = map[string]any{
-		"10.128.0.2": []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)
-
-	staticHost := netip.MustParseAddr("10.128.0.2")
-	otherHost := netip.MustParseAddr("10.128.0.3")
-
-	// Capture the RemoteList pointer up front; an in-flight handshake would hold the same one
-	// on hostinfo.remotes, so it must reflect every reload below.
-	pinned := lh.Query(staticHost)
-	require.NotNil(t, pinned)
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("1.1.1.1:4242")}, pinned.CopyAddrs([]netip.Prefix{}))
-
-	// Replace the remote address. The new address should be the only entry.
-	nc := map[string]any{
-		"static_host_map": map[string]any{
-			"10.128.0.2": []any{"2.2.2.2:4242"},
-		},
-	}
-	rc, err := yaml.Marshal(nc)
-	require.NoError(t, err)
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	rl := lh.Query(staticHost)
-	require.NotNil(t, rl)
-	assert.Same(t, pinned, rl, "RemoteList pointer must stay stable so in-flight handshakes pick up the change")
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("2.2.2.2:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-
-	// Reload back to the original IP. Mirrors the round-trip in issue #718 step 6-8 where
-	// the buggy reload produced [1.1.1.1, 2.2.2.2, 1.1.1.1] instead of [1.1.1.1].
-	nc = map[string]any{
-		"static_host_map": map[string]any{
-			"10.128.0.2": []any{"1.1.1.1:4242"},
-		},
-	}
-	rc, err = yaml.Marshal(nc)
-	require.NoError(t, err)
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	rl = lh.Query(staticHost)
-	require.NotNil(t, rl)
-	assert.Same(t, pinned, rl)
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("1.1.1.1:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-
-	// Reload with the same config. An unchanged entry must not duplicate.
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	rl = lh.Query(staticHost)
-	require.NotNil(t, rl)
-	assert.Same(t, pinned, rl)
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("1.1.1.1:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-
-	// Switch back to 2.2.2.2 so the rest of the test continues against a known address.
-	nc = map[string]any{
-		"static_host_map": map[string]any{
-			"10.128.0.2": []any{"2.2.2.2:4242"},
-		},
-	}
-	rc, err = yaml.Marshal(nc)
-	require.NoError(t, err)
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	// Add a second host alongside the first. Both should be present, neither duplicated.
-	nc = map[string]any{
-		"static_host_map": map[string]any{
-			"10.128.0.2": []any{"2.2.2.2:4242"},
-			"10.128.0.3": []any{"3.3.3.3:4242"},
-		},
-	}
-	rc, err = yaml.Marshal(nc)
-	require.NoError(t, err)
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	rl = lh.Query(staticHost)
-	require.NotNil(t, rl)
-	assert.Same(t, pinned, rl, "adding a sibling entry must not displace the existing RemoteList")
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("2.2.2.2:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-
-	rl = lh.Query(otherHost)
-	require.NotNil(t, rl)
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("3.3.3.3:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-
-	// Drop the first host entirely. The vpnAddr is no longer marked static, our owner
-	// contribution is cleared, but the addrMap entry stays in place so non-static cache
-	// data (from lighthouse queries) on the same RemoteList isn't lost. In-flight handshakes
-	// that already had the pointer see an empty address list rather than retrying stale ones.
-	nc = map[string]any{
-		"static_host_map": map[string]any{
-			"10.128.0.3": []any{"3.3.3.3:4242"},
-		},
-	}
-	rc, err = yaml.Marshal(nc)
-	require.NoError(t, err)
-	require.NoError(t, c.ReloadConfigString(string(rc)))
-
-	_, isStatic := lh.GetStaticHostList()[staticHost]
-	assert.False(t, isStatic)
-
-	rl = lh.Query(staticHost)
-	require.NotNil(t, rl)
-	assert.Same(t, pinned, rl)
-	assert.Empty(t, rl.CopyAddrs([]netip.Prefix{}))
-
-	rl = lh.Query(otherHost)
-	require.NotNil(t, rl)
-	assert.Equal(t, []netip.AddrPort{netip.MustParseAddrPort("3.3.3.3:4242")}, rl.CopyAddrs([]netip.Prefix{}))
-}
-
 func newLHHostRequest(fromAddr netip.AddrPort, myVpnIp, queryVpnIp netip.Addr, lhh *LightHouseHandler) testLhReply {
 	req := &NebulaMeta{
 		Type:    NebulaMeta_HostQuery,

main.go

@@ -194,7 +194,7 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 	handshakeManager := NewHandshakeManager(l, hostMap, lightHouse, udpConns[0], handshakeConfig)
 	lightHouse.handshakeTrigger = handshakeManager.trigger
 
-	ds, err := newDnsServerFromConfig(ctx, l, pki, hostMap, c)
+	ds, err := newDnsServerFromConfig(ctx, l, pki.getCertState(), hostMap, c)
 	if err != nil {
 		l.Warn("Failed to start DNS responder", "error", err)
 	}
@@ -215,6 +215,7 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 		DropLocalBroadcast:    c.GetBool("tun.drop_local_broadcast", false),
 		DropMulticast:         c.GetBool("tun.drop_multicast", false),
 		routines:              routines,
+		batchSize:             c.GetInt("listen.batch", 64),
 		MessageMetrics:        messageMetrics,
 		version:               buildVersion,
 		relayManager:          NewRelayManager(ctx, l, hostMap, c),

noiseutil/cipher_state_test.go

@@ -147,6 +147,62 @@ func buildCipherStatesB(b *testing.B, c noise.CipherFunc) (*noise.CipherState, *
 	return eI, dR
 }
 
+// TestDecryptDangerRelayShapeNoAlloc covers the AD-only relay path used in
+// outside.go's handleOutsideRelayPacket: the body is AD, the trailing 16 bytes
+// are the AEAD tag, the plaintext is empty, and the caller passes nil as the
+// destination because it only needs the auth side-effect. The call must
+// succeed, return an empty plaintext, and not allocate on the hot path.
+func TestDecryptDangerRelayShapeNoAlloc(t *testing.T) {
+	cases := []struct {
+		name string
+		c    noise.CipherFunc
+		wrap func(*noise.CipherState) CipherState
+	}{
+		{"AESGCM", CipherAESGCM, func(cs *noise.CipherState) CipherState { return NewCipherStateAESGCM(cs) }},
+		{"ChaChaPoly", noise.CipherChaChaPoly, func(cs *noise.CipherState) CipherState { return NewCipherStateChaChaPoly(cs) }},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			encCS, decCS := buildCipherStates(t, tc.c)
+			enc, dec := tc.wrap(encCS), tc.wrap(decCS)
+
+			ad := make([]byte, 1200) // typical relay packet body size
+			for i := range ad {
+				ad[i] = byte(i)
+			}
+			nb := make([]byte, 12)
+
+			// Build the "signature value" the way handleOutsideRelayPacket sees it:
+			// empty plaintext encrypted with the body as AD yields just the 16-byte tag.
+			tag, err := enc.EncryptDanger(nil, ad, nil, 1, nb)
+			require.NoError(t, err)
+			require.Len(t, tag, dec.Overhead())
+
+			// Sanity: the relay-shaped call returns empty plaintext, no error.
+			out, err := dec.DecryptDanger(nil, ad, tag, 1, nb)
+			require.NoError(t, err)
+			assert.Empty(t, out)
+
+			// Tampering with the AD must fail authentication.
+			ad[0] ^= 0xff
+			_, err = dec.DecryptDanger(nil, ad, tag, 1, nb)
+			require.Error(t, err)
+			ad[0] ^= 0xff
+
+			// The hot path must not allocate. AllocsPerRun does a warm-up run, so any
+			// one-time setup is excluded. Counter has to advance so the AEAD nonce is
+			// unique per call, but we don't care whether the auth succeeds — we only
+			// care about whether the call path allocates.
+			var counter uint64 = 2
+			allocs := testing.AllocsPerRun(100, func() {
+				_, _ = dec.DecryptDanger(nil, ad, tag, counter, nb)
+				counter++
+			})
+			assert.Equal(t, 0.0, allocs, "DecryptDanger(nil, ...) must not allocate")
+		})
+	}
+}
+
 func TestCipherStateNilSafety(t *testing.T) {
 	var aes *CipherStateAESGCM
 	_, err := aes.EncryptDanger(nil, nil, nil, 0, make([]byte, 12))

outside.go

@@ -22,7 +22,7 @@ const (
 
 var ErrOutOfWindow = errors.New("out of window packet")
 
-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) {
+func (f *Interface) readOutsidePackets(via ViaSender, 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
@@ -110,11 +110,11 @@ func (f *Interface) readOutsidePackets(via ViaSender, out []byte, packet []byte,
 
 	// Relay packets are special
 	if isMessageRelay {
-		f.handleOutsideRelayPacket(hostinfo, via, out, packet, h, fwPacket, lhf, nb, q, localCache)
-
+		f.handleOutsideRelayPacket(hostinfo, via, packet, h, fwPacket, lhf, nb, q, localCache)
 		return
 	}
 
+	out := f.batchers[q].Reserve(len(packet))[:0]
 	out, err = f.decrypt(hostinfo, h.MessageCounter, out, packet, h, nb)
 	if err != nil {
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
@@ -168,7 +168,7 @@ func (f *Interface) readOutsidePackets(via ViaSender, out []byte, packet []byte,
 	}
 }
 
-func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender, out []byte, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
+func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
 	// The entire body is sent as AD, not encrypted.
 	// The packet consists of a 16-byte parsed Nebula header, Associated Data-protected payload, and a trailing 16-byte AEAD signature value.
 	// The packet is guaranteed to be at least 16 bytes at this point, b/c it got past the h.Parse() call above. If it's
@@ -176,16 +176,10 @@ func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender,
 	// which will gracefully fail in the DecryptDanger call.
 	signedPayload := packet[:len(packet)-hostinfo.ConnectionState.dKey.Overhead()]
 	signatureValue := packet[len(packet)-hostinfo.ConnectionState.dKey.Overhead():]
-	var err error
-	out, err = hostinfo.ConnectionState.dKey.DecryptDanger(out, signedPayload, signatureValue, h.MessageCounter, nb)
-	if err != nil {
-		return
-	}
-	// Advance the replay window now that the frame is authenticated
-	if !hostinfo.ConnectionState.window.Update(f.l, h.MessageCounter) {
-		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			hostinfo.logger(f.l).Debug("dropping out of window relay packet", "header", h)
-		}
+	// The decrypted output is empty (relay packets carry their payload as AD) and unused.
+	// The recursive readOutsidePackets call below operates on signedPayload. Passing
+	// nil avoids reserving an arena slot.
+	if _, err := hostinfo.ConnectionState.dKey.DecryptDanger(nil, signedPayload, signatureValue, h.MessageCounter, nb); err != nil {
 		return
 	}
 	// Successfully validated the thing. Get rid of the Relay header.
@@ -201,7 +195,8 @@ func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender,
 		// The only way this happens is if hostmap has an index to the correct HostInfo, but the HostInfo is missing
 		// its internal mapping. This should never happen.
 		hostinfo.logger(f.l).Error("HostInfo missing remote relay index",
-			"relayRemoteIndex", h.RemoteIndex,
+			"vpnAddrs", hostinfo.vpnAddrs,
+			"remoteIndex", h.RemoteIndex,
 		)
 		return
 	}
@@ -217,15 +212,15 @@ func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender,
 			relay:     relay,
 			IsRelayed: true,
 		}
-		f.readOutsidePackets(via, out[:0], signedPayload, h, fwPacket, lhf, nb, q, localCache)
+		f.readOutsidePackets(via, signedPayload, h, fwPacket, lhf, nb, q, localCache)
 	case ForwardingType:
 		// Find the target HostInfo relay object
 		targetHI, targetRelay, err := f.hostMap.QueryVpnAddrsRelayFor(hostinfo.vpnAddrs, relay.PeerAddr)
 		if err != nil {
 			hostinfo.logger(f.l).Info("Failed to find target host info by ip",
 				"relayTo", relay.PeerAddr,
-				"relayFrom", hostinfo.vpnAddrs[0],
 				"error", err,
+				"hostinfo.vpnAddrs", hostinfo.vpnAddrs,
 			)
 			return
 		}
@@ -235,7 +230,8 @@ func (f *Interface) handleOutsideRelayPacket(hostinfo *HostInfo, via ViaSender,
 			switch targetRelay.Type {
 			case ForwardingType:
 				// Forward this packet through the relay tunnel
-				// Find the target HostInfo
+				// Find the target HostInfo //todo it would potentially be nice to batch these
+				out := f.batchers[q].Reserve(len(packet) + header.Len + hostinfo.ConnectionState.dKey.Overhead())[:0]
 				f.SendVia(targetHI, targetRelay, signedPayload, nb, out, false)
 			case TerminalType:
 				hostinfo.logger(f.l).Error("Unexpected Relay Type of Terminal")
@@ -542,7 +538,7 @@ func (f *Interface) handleOutsideMessagePacket(hostinfo *HostInfo, out []byte, p
 		return
 	}
 
-	_, err = f.readers[q].Write(out)
+	err = f.batchers[q].Commit(out)
 	if err != nil {
 		f.l.Error("Failed to write to tun", "error", err)
 	}

overlay/batch/coalesce_core.go

@@ -0,0 +1,42 @@
+package batch
+
+// Arena is an injectable byte-slab that hands out non-overlapping borrowed
+// slices via Reserve and releases them in bulk via Reset. Coalescers take
+// an *Arena at construction so the caller controls the slab lifetime and
+// can share one slab across multiple coalescers (MultiCoalescer hands the
+// same *Arena to every lane so the lanes don't carry their own backings).
+//
+// Reserve borrows; the slice is valid until the next Reset. The slab grows
+// (by allocating a fresh, larger backing array) if a Reserve doesn't fit;
+// pre-size the arena via NewArena to avoid that path on the hot path.
+type Arena struct {
+	buf []byte
+}
+
+// NewArena returns an Arena with a pre-allocated backing of the given
+// capacity. Pass 0 if you don't intend to call Reserve (e.g. a test that
+// only feeds the coalescer pre-made []byte packets via Commit).
+func NewArena(capacity int) *Arena {
+	return &Arena{buf: make([]byte, 0, capacity)}
+}
+
+// Reserve hands out a non-overlapping sz-byte slice from the arena. If the
+// request doesn't fit the current backing, a fresh, larger backing is
+// allocated; already-borrowed slices reference the old backing and remain
+// valid until Reset.
+func (a *Arena) Reserve(sz int) []byte {
+	if len(a.buf)+sz > cap(a.buf) {
+		newCap := max(cap(a.buf)*2, sz)
+		a.buf = make([]byte, 0, newCap)
+	}
+	start := len(a.buf)
+	a.buf = a.buf[:start+sz]
+	return a.buf[start : start+sz : start+sz]
+}
+
+// Reset releases every slice handed out since the last Reset. Callers must
+// not use any previously-borrowed slice after this returns. The underlying
+// backing array is retained so subsequent Reserves don't re-allocate.
+func (a *Arena) Reset() {
+	a.buf = a.buf[:0]
+}

overlay/batch/passthrough.go

@@ -0,0 +1,46 @@
+package batch
+
+import (
+	"io"
+
+	"github.com/slackhq/nebula/util"
+)
+
+// Passthrough is a RxBatcher that doesn't batch anything, it just accumulates and then sends packets.
+type Passthrough struct {
+	out    io.Writer
+	slots  [][]byte
+	arena  *util.Arena
+	cursor int
+}
+
+func NewPassthrough(w io.Writer, slots int, arena *util.Arena) *Passthrough {
+	return &Passthrough{
+		out:   w,
+		slots: make([][]byte, 0, slots),
+		arena: arena,
+	}
+}
+
+func (p *Passthrough) Reserve(sz int) []byte {
+	return p.arena.Reserve(sz)
+}
+
+func (p *Passthrough) Commit(pkt []byte) error {
+	p.slots = append(p.slots, pkt)
+	return nil
+}
+
+func (p *Passthrough) Flush() error {
+	var firstErr error
+	for _, s := range p.slots {
+		_, err := p.out.Write(s)
+		if err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+	clear(p.slots)
+	p.slots = p.slots[:0]
+	p.arena.Reset()
+	return firstErr
+}

overlay/batch/rx_batch.go

@@ -0,0 +1,12 @@
+package batch
+
+type RxBatcher interface {
+	// Reserve creates a pkt to borrow
+	Reserve(sz int) []byte
+	// Commit borrows pkt. The caller must keep pkt valid until the next Flush
+	Commit(pkt []byte) error
+	// Flush emits every queued packet in arrival order. Returns the
+	// first error observed; keeps draining so one bad packet doesn't hold up
+	// the rest. After Flush returns, borrowed payload slices may be recycled.
+	Flush() error
+}

overlay/batch/tx_batch.go

@@ -0,0 +1,60 @@
+package batch
+
+import (
+	"net/netip"
+
+	"github.com/slackhq/nebula/util"
+)
+
+const SendBatchCap = 128
+
+// batchWriter is the minimal subset of udp.Conn needed by SendBatch to flush.
+type batchWriter interface {
+	WriteBatch(bufs [][]byte, addrs []netip.AddrPort, outerECNs []byte) error
+}
+
+// SendBatch accumulates encrypted UDP packets and flushes them via WriteBatch.
+// One SendBatch is owned by each listenIn goroutine; no locking is needed.
+// Slot bytes are borrowed from the injected Arena and remain valid until
+// Flush, which Resets the arena.
+type SendBatch struct {
+	out   batchWriter
+	bufs  [][]byte
+	dsts  []netip.AddrPort
+	ecns  []byte
+	arena *util.Arena
+}
+
+// NewSendBatch makes a SendBatch with batchCap slots backed by arena.
+func NewSendBatch(out batchWriter, batchCap int, arena *util.Arena) *SendBatch {
+	return &SendBatch{
+		out:   out,
+		bufs:  make([][]byte, 0, batchCap),
+		dsts:  make([]netip.AddrPort, 0, batchCap),
+		ecns:  make([]byte, 0, batchCap),
+		arena: arena,
+	}
+}
+
+func (b *SendBatch) Reserve(sz int) []byte {
+	return b.arena.Reserve(sz)
+}
+
+func (b *SendBatch) Commit(pkt []byte, dst netip.AddrPort, outerECN byte) {
+	b.bufs = append(b.bufs, pkt)
+	b.dsts = append(b.dsts, dst)
+	b.ecns = append(b.ecns, outerECN)
+}
+
+func (b *SendBatch) Flush() error {
+	var err error
+	if len(b.bufs) > 0 {
+		err = b.out.WriteBatch(b.bufs, b.dsts, b.ecns)
+	}
+	clear(b.bufs)
+	b.bufs = b.bufs[:0]
+	b.dsts = b.dsts[:0]
+	b.ecns = b.ecns[:0]
+	b.arena.Reset()
+	return err
+}

overlay/batch/tx_batch_test.go

@@ -0,0 +1,126 @@
+package batch
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/slackhq/nebula/util"
+)
+
+type fakeBatchWriter struct {
+	bufs  [][]byte
+	addrs []netip.AddrPort
+	ecns  []byte
+}
+
+func (w *fakeBatchWriter) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, ecns []byte) error {
+	// Snapshot — SendBatch.Flush nils its slot pointers right after WriteBatch
+	// returns, so tests must capture data before that happens.
+	w.bufs = make([][]byte, len(bufs))
+	for i, b := range bufs {
+		cp := make([]byte, len(b))
+		copy(cp, b)
+		w.bufs[i] = cp
+	}
+	w.addrs = append(w.addrs[:0], addrs...)
+	w.ecns = append(w.ecns[:0], ecns...)
+	return nil
+}
+
+func TestSendBatchReserveCommitFlush(t *testing.T) {
+	fw := &fakeBatchWriter{}
+	b := NewSendBatch(fw, 4, util.NewArena(32))
+
+	ap := netip.MustParseAddrPort("10.0.0.1:4242")
+	for i := 0; i < 4; i++ {
+		slot := b.Reserve(32)
+		if cap(slot) != 32 {
+			t.Fatalf("slot %d: cap=%d want 32", i, cap(slot))
+		}
+		pkt := append(slot[:0], byte(i), byte(i+1), byte(i+2))
+		b.Commit(pkt, ap, 0)
+	}
+	if err := b.Flush(); err != nil {
+		t.Fatalf("Flush: %v", err)
+	}
+	if len(fw.bufs) != 4 {
+		t.Fatalf("WriteBatch got %d bufs want 4", len(fw.bufs))
+	}
+	for i, buf := range fw.bufs {
+		if len(buf) != 3 || buf[0] != byte(i) {
+			t.Errorf("buf %d: %x", i, buf)
+		}
+		if fw.addrs[i] != ap {
+			t.Errorf("addr %d: got %v want %v", i, fw.addrs[i], ap)
+		}
+	}
+
+	// Flush again with nothing committed — should be a no-op.
+	fw.bufs = nil
+	if err := b.Flush(); err != nil {
+		t.Fatalf("empty Flush: %v", err)
+	}
+	if fw.bufs != nil {
+		t.Fatalf("empty Flush triggered WriteBatch")
+	}
+
+	// Reuse after Flush.
+	slot := b.Reserve(32)
+	if cap(slot) != 32 {
+		t.Fatalf("after Flush Reserve wrong cap: %d", cap(slot))
+	}
+}
+
+func TestSendBatchSlotsDoNotOverlap(t *testing.T) {
+	fw := &fakeBatchWriter{}
+	b := NewSendBatch(fw, 3, util.NewArena(8))
+	ap := netip.MustParseAddrPort("10.0.0.1:80")
+
+	for i := 0; i < 3; i++ {
+		s := b.Reserve(8)
+		pkt := append(s[:0], byte(0xA0+i), byte(0xB0+i))
+		b.Commit(pkt, ap, 0)
+	}
+	if err := b.Flush(); err != nil {
+		t.Fatalf("Flush: %v", err)
+	}
+
+	for i, buf := range fw.bufs {
+		if buf[0] != byte(0xA0+i) || buf[1] != byte(0xB0+i) {
+			t.Errorf("slot %d corrupted: %x", i, buf)
+		}
+	}
+}
+
+func TestSendBatchGrowPreservesCommitted(t *testing.T) {
+	fw := &fakeBatchWriter{}
+	// Tiny initial backing forces a grow on the second Reserve.
+	b := NewSendBatch(fw, 1, util.NewArena(4))
+	ap := netip.MustParseAddrPort("10.0.0.1:80")
+
+	s1 := b.Reserve(4)
+	pkt1 := append(s1[:0], 0x11, 0x22, 0x33, 0x44)
+	b.Commit(pkt1, ap, 0)
+
+	s2 := b.Reserve(8) // exceeds remaining cap, triggers grow
+	pkt2 := append(s2[:0], 0xA, 0xB, 0xC, 0xD, 0xE)
+	b.Commit(pkt2, ap, 0)
+
+	// pkt1 must still be intact even though backing reallocated.
+	if pkt1[0] != 0x11 || pkt1[3] != 0x44 {
+		t.Fatalf("first packet corrupted by grow: %x", pkt1)
+	}
+
+	if err := b.Flush(); err != nil {
+		t.Fatalf("Flush: %v", err)
+	}
+	if len(fw.bufs) != 2 {
+		t.Fatalf("got %d bufs want 2", len(fw.bufs))
+	}
+	if fw.bufs[0][0] != 0x11 || fw.bufs[0][3] != 0x44 {
+		t.Errorf("first packet on the wire: %x", fw.bufs[0])
+	}
+	if fw.bufs[1][0] != 0xA || fw.bufs[1][4] != 0xE {
+		t.Errorf("second packet on the wire: %x", fw.bufs[1])
+	}
+}

overlay/device.go

@@ -4,15 +4,21 @@ import (
 	"io"
 	"net/netip"
 
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 )
 
+// defaultBatchBufSize is the per-Queue scratch size for Read on backends
+// that don't do TSO segmentation. 65535 covers any single IP packet.
+const defaultBatchBufSize = 65535
+
 type Device interface {
-	io.ReadWriteCloser
+	io.Closer
 	Activate() error
 	Networks() []netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
 	SupportsMultiqueue() bool
-	NewMultiQueueReader() (io.ReadWriteCloser, error)
+	NewMultiQueueReader() error
+	Readers() []tio.Queue
 }

overlay/overlaytest/noop.go

@@ -4,10 +4,11 @@ package overlaytest
 
 import (
 	"errors"
-	"io"
 	"net/netip"
 
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
+	"github.com/slackhq/nebula/wire"
 )
 
 // NoopTun is an overlay.Device that silently discards every read and write.
@@ -15,6 +16,10 @@ import (
 // exercise the datapath.
 type NoopTun struct{}
 
+func (NoopTun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
 func (NoopTun) RoutesFor(addr netip.Addr) routing.Gateways {
 	return routing.Gateways{}
 }
@@ -31,7 +36,7 @@ func (NoopTun) Name() string {
 	return "noop"
 }
 
-func (NoopTun) Read([]byte) (int, error) {
+func (NoopTun) Read(p []wire.TunPacket, mem []byte) (int, error) {
 	return 0, nil
 }
 
@@ -43,8 +48,12 @@ func (NoopTun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (NoopTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, errors.New("unsupported")
+func (NoopTun) NewMultiQueueReader() error {
+	return errors.New("unsupported")
+}
+
+func (NoopTun) Readers() []tio.Queue {
+	return []tio.Queue{NoopTun{}}
 }
 
 func (NoopTun) Close() error {

overlay/tio/queueset_poll_linux.go

@@ -0,0 +1,80 @@
+package tio
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+type pollQueueSet struct {
+	pq []*Poll
+	// pqi is exactly the same as pq, but stored as the interface type
+	pqi        []Queue
+	shutdownFd int
+}
+
+func NewPollQueueSet() (QueueSet, error) {
+	shutdownFd, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create eventfd: %w", err)
+	}
+
+	out := &pollQueueSet{
+		pq:         []*Poll{},
+		pqi:        []Queue{},
+		shutdownFd: shutdownFd,
+	}
+
+	return out, nil
+}
+
+func (c *pollQueueSet) Queues() []Queue {
+	return c.pqi
+}
+
+func (c *pollQueueSet) Add(fd int) error {
+	x, err := newPoll(fd, c.shutdownFd)
+	if err != nil {
+		return err
+	}
+	c.pq = append(c.pq, x)
+	c.pqi = append(c.pqi, x)
+
+	return nil
+}
+
+func (c *pollQueueSet) wakeForShutdown() error {
+	var buf [8]byte
+	binary.NativeEndian.PutUint64(buf[:], 1)
+	_, err := unix.Write(c.shutdownFd, buf[:])
+	return err
+}
+
+func (c *pollQueueSet) Close() error {
+	if c.shutdownFd < 0 {
+		return nil
+	}
+
+	errs := []error{}
+
+	if err := c.wakeForShutdown(); err != nil {
+		errs = append(errs, err)
+	}
+
+	for _, x := range c.pq {
+		if err := x.Close(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	// All Polls reference shutdownFd in their pollfd arrays, so close it
+	// only after every Poll.Close has returned.
+	if err := unix.Close(c.shutdownFd); err != nil {
+		errs = append(errs, err)
+	}
+	c.shutdownFd = -1
+
+	return errors.Join(errs...)
+}

overlay/tio/tio.go

@@ -0,0 +1,122 @@
+package tio
+
+import (
+	"io"
+
+	"github.com/slackhq/nebula/wire"
+)
+
+// QueueSet holds one or many Queue objects and helps close them in an orderly way.
+type QueueSet interface {
+	io.Closer
+	Queues() []Queue
+
+	// Add takes a tun fd, adds it to the set, and prepares it for use as a Queue.
+	Add(fd int) error
+}
+
+// Capabilities advertises which kernel offload features a Queue successfully negotiated.
+// Callers consult this to decide which coalescers to wire onto the write path.
+type Capabilities struct {
+	// TSO means the FD was opened with IFF_VNET_HDR and the kernel agreed
+	// to TUN_F_TSO4|TSO6 — i.e. WriteGSO with GSOProtoTCP is safe.
+	TSO bool
+	// USO means the kernel additionally agreed to TUN_F_USO4|USO6, so
+	// WriteGSO with GSOProtoUDP is safe. Linux ≥ 6.2.
+	USO bool
+}
+
+// Queue is a readable/writable Poll queue. One Queue is driven by a single
+// read goroutine plus a single writer (see Write below).
+type Queue interface {
+	io.Closer
+
+	// Read will read at least 1 packet from the tun (up to len(p)).
+	// mem will be used to provide the backing for each of p[n].Bytes.
+	// Callers should size mem and p to avoid exhausting mem before p.
+	// Returns the number of packets actually read, or error.
+	Read(p []wire.TunPacket, mem []byte) (int, error)
+
+	// Write emits a single packet on the plaintext (outside→inside)
+	// delivery path.
+	Write(p []byte) (int, error)
+
+	// Capabilities returns the Queue's negotiated offload capabilities,
+	// or the zero value when q does not advertise any.
+	Capabilities() Capabilities
+}
+
+// GSOInfo describes a kernel-supplied superpacket sitting in Packet.Bytes.
+// The zero value means "not a superpacket" — Bytes is one regular IP
+// datagram and no segmentation is required.
+type GSOInfo struct {
+	// Size is the GSO segment size: max payload bytes per segment
+	// (== TCP MSS for TSO, == UDP payload chunk for USO). Zero means
+	// not a superpacket.
+	Size uint16
+	// HdrLen is the total L3+L4 header length within Bytes (already
+	// corrected via correctHdrLen, so safe to slice on).
+	HdrLen uint16
+	// CsumStart is the L4 header offset inside Bytes (== L3 header
+	// length).
+	CsumStart uint16
+	// Proto picks the L4 protocol (TCP or UDP) so the segmenter knows
+	// which checksum/header layout to apply.
+	Proto GSOProto
+}
+
+// GSOProto selects the L4 protocol for a GSO superpacket. Determines which
+// VIRTIO_NET_HDR_GSO_* type the writer stamps and which checksum offset
+// inside the transport header virtio NEEDS_CSUM expects.
+type GSOProto uint8
+
+const (
+	GSOProtoNone GSOProto = iota
+	GSOProtoTCP
+	GSOProtoUDP
+)
+
+// GSOWriter is implemented by Queues that can emit a TCP or UDP superpacket
+// assembled from a header prefix plus one or more borrowed payload
+// fragments, in a single vectored write (writev with a leading
+// virtio_net_hdr). This lets the coalescer avoid copying payload bytes
+// between the caller's decrypt buffer and the TUN. Backends without GSO
+// support do not implement this interface and coalescing is skipped.
+//
+// hdr contains the IPv4/IPv6 header prefix (mutable - callers will have
+// filled in total length and IP csum). transportHdr is the TCP or UDP
+// header (mutable - the L4 checksum field must hold the pseudo-header
+// partial, single-fold not inverted, per virtio NEEDS_CSUM semantics).
+// pays are non-overlapping payload fragments whose concatenation is the
+// full superpacket payload; they are read-only from the writer's
+// perspective and must remain valid until the call returns. Every segment
+// in pays except possibly the last is exactly the same size. proto picks
+// the L4 protocol so the writer knows which GSOType / CsumOffset to set.
+//
+// Callers should also consult CapsProvider (via SupportsGSO or
+// QueueCapabilities) for the per-protocol negotiated capability; an
+// implementation of GSOWriter is necessary but not sufficient since USO
+// may not have been negotiated even when TSO was.
+type GSOWriter interface {
+	WriteGSO(hdr []byte, transportHdr []byte, pays [][]byte, proto GSOProto) error
+}
+
+// SupportsGSO reports whether w implements GSOWriter and the underlying
+// queue advertises the negotiated capability for `want`. A writer that
+// implements GSOWriter but not CapsProvider is treated as permissive
+// (used by tests and fakes that don't negotiate).
+func SupportsGSO(w Queue, want GSOProto) (GSOWriter, bool) {
+	gw, ok := w.(GSOWriter)
+	if !ok {
+		return nil, false
+	}
+	caps := w.Capabilities()
+	switch want {
+	case GSOProtoTCP:
+		return gw, caps.TSO
+	case GSOProtoUDP:
+		return gw, caps.USO
+	default:
+		return gw, false
+	}
+}

overlay/tio/tio_poll_linux.go

@@ -0,0 +1,168 @@
+package tio
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"sync/atomic"
+
+	"github.com/slackhq/nebula/wire"
+	"golang.org/x/sys/unix"
+)
+
+type Poll struct {
+	fd int
+
+	readPoll  [2]unix.PollFd
+	writePoll [2]unix.PollFd
+	writeLock sync.Mutex
+	closed    atomic.Bool
+}
+
+func newPoll(fd int, shutdownFd int) (*Poll, error) {
+	if err := unix.SetNonblock(fd, true); err != nil {
+		_ = unix.Close(fd)
+		return nil, fmt.Errorf("failed to set Poll device as nonblocking: %w", err)
+	}
+
+	out := &Poll{
+		fd: fd,
+		readPoll: [2]unix.PollFd{
+			{Fd: int32(fd), Events: unix.POLLIN},
+			{Fd: int32(shutdownFd), Events: unix.POLLIN},
+		},
+		writePoll: [2]unix.PollFd{
+			{Fd: int32(fd), Events: unix.POLLOUT},
+			{Fd: int32(shutdownFd), Events: unix.POLLIN},
+		},
+		writeLock: sync.Mutex{},
+	}
+	return out, nil
+}
+
+// blockOnRead waits until the Poll fd is readable or shutdown has been signaled.
+// Returns os.ErrClosed if Close was called.
+func (t *Poll) blockOnRead() error {
+	const problemFlags = unix.POLLHUP | unix.POLLNVAL | unix.POLLERR
+	var err error
+	for {
+		_, err = unix.Poll(t.readPoll[:], -1)
+		if err != unix.EINTR {
+			break
+		}
+	}
+	tunEvents := t.readPoll[0].Revents
+	shutdownEvents := t.readPoll[1].Revents
+	t.readPoll[0].Revents = 0
+	t.readPoll[1].Revents = 0
+	if err != nil {
+		return err
+	}
+	if shutdownEvents&(unix.POLLIN|problemFlags) != 0 {
+		return os.ErrClosed
+	}
+	if tunEvents&problemFlags != 0 {
+		return os.ErrClosed
+	}
+	return nil
+}
+
+func (t *Poll) blockOnWrite() error {
+	const problemFlags = unix.POLLHUP | unix.POLLNVAL | unix.POLLERR
+	var err error
+	for {
+		_, err = unix.Poll(t.writePoll[:], -1)
+		if err != unix.EINTR {
+			break
+		}
+	}
+	t.writeLock.Lock()
+	tunEvents := t.writePoll[0].Revents
+	shutdownEvents := t.writePoll[1].Revents
+	t.writePoll[0].Revents = 0
+	t.writePoll[1].Revents = 0
+	t.writeLock.Unlock()
+	if err != nil {
+		return err
+	}
+	if shutdownEvents&(unix.POLLIN|problemFlags) != 0 {
+		return os.ErrClosed
+	}
+	if tunEvents&problemFlags != 0 {
+		return os.ErrClosed
+	}
+	return nil
+}
+
+func (t *Poll) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.readOne(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
+func (t *Poll) readOne(to []byte) (int, error) {
+	for {
+		n, errno := unix.Read(t.fd, to)
+		if errno == nil {
+			return n, nil
+		}
+		switch errno {
+		case unix.EAGAIN:
+			if err := t.blockOnRead(); err != nil {
+				return 0, err
+			}
+		case unix.EINTR:
+			// retry
+		case unix.EBADF:
+			return 0, os.ErrClosed
+		default:
+			return 0, errno
+		}
+	}
+}
+
+func (t *Poll) Write(from []byte) (int, error) {
+	for {
+		n, errno := unix.Write(t.fd, from)
+		if errno == nil {
+			return n, nil
+		}
+		switch errno {
+		case unix.EAGAIN:
+			if err := t.blockOnWrite(); err != nil {
+				return 0, err
+			}
+		case unix.EINTR:
+			// retry
+		case unix.EBADF:
+			return 0, os.ErrClosed
+		default:
+			return 0, errno
+		}
+	}
+}
+
+func (t *Poll) Close() error {
+	if t.closed.Swap(true) {
+		return nil
+	}
+	//shutdownFd is owned by the container, so we should not close it
+	var err error
+	if t.fd >= 0 {
+		err = unix.Close(t.fd)
+		t.fd = -1
+	}
+
+	return err
+}
+
+func (t *Poll) Capabilities() Capabilities {
+	return Capabilities{}
+}

overlay/tio/tun_file_linux_test.go

@@ -0,0 +1,106 @@
+//go:build linux && !android && !e2e_testing
+// +build linux,!android,!e2e_testing
+
+package tio
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/slackhq/nebula/wire"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/unix"
+)
+
+// newReadPipe returns a read fd. The matching write fd is registered for cleanup.
+// The caller takes ownership of the read fd (pass it into a QueueSet).
+func newReadPipe(t *testing.T) int {
+	t.Helper()
+	var fds [2]int
+	if err := unix.Pipe2(fds[:], unix.O_CLOEXEC); err != nil {
+		t.Fatalf("pipe2: %v", err)
+	}
+	t.Cleanup(func() { _ = unix.Close(fds[1]) })
+	return fds[0]
+}
+
+func TestPoll_WakeForShutdown_WakesFriends(t *testing.T) {
+	parent, err := NewPollQueueSet()
+	require.NoError(t, err)
+	require.NoError(t, parent.Add(newReadPipe(t)))
+	require.NoError(t, parent.Add(newReadPipe(t)))
+	// QueueSet.Close owns the read fds we Added — don't register a separate
+	// Cleanup to close them or we'll double-close whatever fd the kernel
+	// has since reused.
+
+	readers := parent.Queues()
+	errs := make([]error, len(readers))
+	var wg sync.WaitGroup
+	for i, r := range readers {
+		wg.Add(1)
+		go func(i int, r Queue) {
+			defer wg.Done()
+			pkts := make([]wire.TunPacket, 1)
+			_, errs[i] = r.Read(pkts, make([]byte, 64))
+		}(i, r)
+	}
+
+	time.Sleep(50 * time.Millisecond)
+
+	if err := parent.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+
+	done := make(chan struct{})
+	go func() { wg.Wait(); close(done) }()
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("readers did not wake")
+	}
+
+	for i, err := range errs {
+		if !errors.Is(err, os.ErrClosed) {
+			t.Errorf("reader %d: expected os.ErrClosed, got %v", i, err)
+		}
+	}
+}
+
+func TestPoll_Close_Idempotent(t *testing.T) {
+	shutdownFd, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
+	require.NoError(t, err)
+	t.Cleanup(func() { _ = unix.Close(shutdownFd) })
+
+	tf, err := newPoll(newReadPipe(t), shutdownFd)
+	require.NoError(t, err)
+	if err := tf.Close(); err != nil {
+		t.Fatalf("first Close: %v", err)
+	}
+	if err := tf.Close(); err != nil {
+		t.Fatalf("second Close should be a no-op, got %v", err)
+	}
+}
+
+func TestPollQueueSet_Close_ClosesEventfd(t *testing.T) {
+	qs, err := NewPollQueueSet()
+	require.NoError(t, err)
+	require.NoError(t, qs.Add(newReadPipe(t)))
+
+	fd := qs.(*pollQueueSet).shutdownFd
+	require.NoError(t, qs.Close())
+
+	// Closing the eventfd again should fail with EBADF, proving Close
+	// actually released it.
+	if err := unix.Close(fd); err == nil {
+		t.Fatalf("eventfd %d still open after QueueSet.Close", fd)
+	}
+
+	// Second Close must be a no-op (and must not double-close the eventfd
+	// in case the kernel handed it out to another caller in the meantime).
+	if err := qs.Close(); err != nil {
+		t.Fatalf("second Close: %v", err)
+	}
+}

overlay/tun_android.go

@@ -13,12 +13,14 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 )
 
 type tun struct {
-	io.ReadWriteCloser
+	rwc         io.ReadWriteCloser
 	fd          int
 	vpnNetworks []netip.Prefix
 	Routes      atomic.Pointer[[]Route]
@@ -26,16 +28,37 @@ type tun struct {
 	l           *slog.Logger
 }
 
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.rwc.Read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
+func (t *tun) Write(p []byte) (int, error) {
+	return t.rwc.Write(p)
+}
+
+func (t *tun) Close() error {
+	return t.rwc.Close()
+}
+
 func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []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")
 
 	t := &tun{
-		ReadWriteCloser: file,
-		fd:              deviceFd,
-		vpnNetworks:     vpnNetworks,
-		l:               l,
+		rwc:         file,
+		fd:          deviceFd,
+		vpnNetworks: vpnNetworks,
+		l:           l,
 	}
 
 	err := t.reload(c, true)
@@ -62,7 +85,7 @@ func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
 	return r
 }
 
-func (t tun) Activate() error {
+func (t *tun) Activate() error {
 	return nil
 }
 
@@ -99,6 +122,14 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for android")
+func (t *tun) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for android")
+}
+
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
 }

overlay/tun_darwin.go

@@ -16,14 +16,16 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 	netroute "golang.org/x/net/route"
 	"golang.org/x/sys/unix"
 )
 
 type tun struct {
-	io.ReadWriteCloser
+	rwc         io.ReadWriteCloser
 	Device      string
 	vpnNetworks []netip.Prefix
 	DefaultMTU  int
@@ -124,11 +126,11 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 	}
 
 	t := &tun{
-		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
-		Device:          name,
-		vpnNetworks:     vpnNetworks,
-		DefaultMTU:      c.GetInt("tun.mtu", DefaultMTU),
-		l:               l,
+		rwc:         os.NewFile(uintptr(fd), ""),
+		Device:      name,
+		vpnNetworks: vpnNetworks,
+		DefaultMTU:  c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
 	}
 
 	err = t.reload(c, true)
@@ -158,8 +160,8 @@ func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (*tun, e
 }
 
 func (t *tun) Close() error {
-	if t.ReadWriteCloser != nil {
-		return t.ReadWriteCloser.Close()
+	if t.rwc != nil {
+		return t.rwc.Close()
 	}
 	return nil
 }
@@ -502,13 +504,17 @@ func delRoute(prefix netip.Prefix, gateway netroute.Addr) error {
 	return nil
 }
 
-func (t *tun) Read(to []byte) (int, error) {
-	buf := make([]byte, len(to)+4)
-
-	n, err := t.ReadWriteCloser.Read(buf)
-
-	copy(to, buf[4:])
-	return n - 4, err
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) <= 4 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.rwc.Read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[4:n]
+	return 1, nil
 }
 
 // Write is only valid for single threaded use
@@ -536,7 +542,7 @@ func (t *tun) Write(from []byte) (int, error) {
 
 	copy(buf[4:], from)
 
-	n, err := t.ReadWriteCloser.Write(buf)
+	n, err := t.rwc.Write(buf)
 	return n - 4, err
 }
 
@@ -552,6 +558,14 @@ 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 (t *tun) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for darwin")
+}
+
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
 }

overlay/tun_disabled.go

@@ -10,7 +10,9 @@ import (
 
 	"github.com/rcrowley/go-metrics"
 	"github.com/slackhq/nebula/iputil"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
+	"github.com/slackhq/nebula/wire"
 )
 
 type disabledTun struct {
@@ -18,9 +20,10 @@ type disabledTun struct {
 	vpnNetworks []netip.Prefix
 
 	// Track these metrics since we don't have the tun device to do it for us
-	tx metrics.Counter
-	rx metrics.Counter
-	l  *slog.Logger
+	tx         metrics.Counter
+	rx         metrics.Counter
+	numReaders int
+	l          *slog.Logger
 }
 
 func newDisabledTun(vpnNetworks []netip.Prefix, queueLen int, metricsEnabled bool, l *slog.Logger) *disabledTun {
@@ -28,6 +31,7 @@ func newDisabledTun(vpnNetworks []netip.Prefix, queueLen int, metricsEnabled boo
 		vpnNetworks: vpnNetworks,
 		read:        make(chan []byte, queueLen),
 		l:           l,
+		numReaders:  1,
 	}
 
 	if metricsEnabled {
@@ -57,7 +61,7 @@ func (*disabledTun) Name() string {
 	return "disabled"
 }
 
-func (t *disabledTun) Read(b []byte) (int, error) {
+func (t *disabledTun) readOne(b []byte) (int, error) {
 	r, ok := <-t.read
 	if !ok {
 		return 0, io.EOF
@@ -75,6 +79,19 @@ func (t *disabledTun) Read(b []byte) (int, error) {
 	return copy(b, r), nil
 }
 
+func (t *disabledTun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.readOne(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
 func (t *disabledTun) handleICMPEchoRequest(b []byte) bool {
 	out := make([]byte, len(b))
 	out = iputil.CreateICMPEchoResponse(b, out)
@@ -110,8 +127,21 @@ func (t *disabledTun) SupportsMultiqueue() bool {
 	return true
 }
 
-func (t *disabledTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return t, nil
+func (t *disabledTun) NewMultiQueueReader() error {
+	t.numReaders++
+	return nil
+}
+
+func (t *disabledTun) Readers() []tio.Queue {
+	out := make([]tio.Queue, t.numReaders)
+	for i := range t.numReaders {
+		out[i] = t
+	}
+	return out
+}
+
+func (t *disabledTun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
 }
 
 func (t *disabledTun) Close() error {

overlay/tun_file_linux_test.go

@@ -1,120 +0,0 @@
-//go:build linux && !android && !e2e_testing
-// +build linux,!android,!e2e_testing
-
-package overlay
-
-import (
-	"errors"
-	"os"
-	"sync"
-	"testing"
-	"time"
-
-	"golang.org/x/sys/unix"
-)
-
-// newReadPipe returns a read fd. The matching write fd is registered for cleanup.
-// The caller takes ownership of the read fd (pass it to newTunFd / newFriend).
-func newReadPipe(t *testing.T) int {
-	t.Helper()
-	var fds [2]int
-	if err := unix.Pipe2(fds[:], unix.O_CLOEXEC); err != nil {
-		t.Fatalf("pipe2: %v", err)
-	}
-	t.Cleanup(func() { _ = unix.Close(fds[1]) })
-	return fds[0]
-}
-
-func TestTunFile_WakeForShutdown_UnblocksRead(t *testing.T) {
-	tf, err := newTunFd(newReadPipe(t))
-	if err != nil {
-		t.Fatalf("newTunFd: %v", err)
-	}
-	t.Cleanup(func() { _ = tf.Close() })
-
-	done := make(chan error, 1)
-	go func() {
-		_, err := tf.Read(make([]byte, 64))
-		done <- err
-	}()
-
-	// Verify Read is actually blocked in poll.
-	select {
-	case err := <-done:
-		t.Fatalf("Read returned before shutdown signal: %v", err)
-	case <-time.After(50 * time.Millisecond):
-	}
-
-	if err := tf.wakeForShutdown(); err != nil {
-		t.Fatalf("wakeForShutdown: %v", err)
-	}
-
-	select {
-	case err := <-done:
-		if !errors.Is(err, os.ErrClosed) {
-			t.Fatalf("expected os.ErrClosed, got %v", err)
-		}
-	case <-time.After(2 * time.Second):
-		t.Fatal("Read did not wake on shutdown")
-	}
-}
-
-func TestTunFile_WakeForShutdown_WakesFriends(t *testing.T) {
-	parent, err := newTunFd(newReadPipe(t))
-	if err != nil {
-		t.Fatalf("newTunFd: %v", err)
-	}
-	friend, err := parent.newFriend(newReadPipe(t))
-	if err != nil {
-		_ = parent.Close()
-		t.Fatalf("newFriend: %v", err)
-	}
-	t.Cleanup(func() {
-		_ = friend.Close()
-		_ = parent.Close()
-	})
-
-	readers := []*tunFile{parent, friend}
-	errs := make([]error, len(readers))
-	var wg sync.WaitGroup
-	for i, r := range readers {
-		wg.Add(1)
-		go func(i int, r *tunFile) {
-			defer wg.Done()
-			_, errs[i] = r.Read(make([]byte, 64))
-		}(i, r)
-	}
-
-	time.Sleep(50 * time.Millisecond)
-
-	if err := parent.wakeForShutdown(); err != nil {
-		t.Fatalf("wakeForShutdown: %v", err)
-	}
-
-	done := make(chan struct{})
-	go func() { wg.Wait(); close(done) }()
-	select {
-	case <-done:
-	case <-time.After(2 * time.Second):
-		t.Fatal("readers did not wake")
-	}
-
-	for i, err := range errs {
-		if !errors.Is(err, os.ErrClosed) {
-			t.Errorf("reader %d: expected os.ErrClosed, got %v", i, err)
-		}
-	}
-}
-
-func TestTunFile_Close_Idempotent(t *testing.T) {
-	tf, err := newTunFd(newReadPipe(t))
-	if err != nil {
-		t.Fatalf("newTunFd: %v", err)
-	}
-	if err := tf.Close(); err != nil {
-		t.Fatalf("first Close: %v", err)
-	}
-	if err := tf.Close(); err != nil {
-		t.Fatalf("second Close should be a no-op, got %v", err)
-	}
-}

overlay/tun_freebsd.go

@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io"
 	"io/fs"
 	"log/slog"
 	"net/netip"
@@ -18,9 +17,10 @@ import (
 	"unsafe"
 
 	"github.com/gaissmai/bart"
+	"github.com/slackhq/nebula/wire"
 
 	"github.com/slackhq/nebula/config"
-
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
 	netroute "golang.org/x/net/route"
@@ -157,7 +157,20 @@ func (t *tun) blockOnWrite() error {
 	return nil
 }
 
-func (t *tun) Read(to []byte) (int, error) {
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.readOne(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
+func (t *tun) readOne(to []byte) (int, error) {
 	// first 4 bytes is protocol family, in network byte order
 	var head [4]byte
 	iovecs := [2]syscall.Iovec{
@@ -565,8 +578,8 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
+func (t *tun) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for freebsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
@@ -593,6 +606,14 @@ func (t *tun) addRoutes(logErrors bool) error {
 	return nil
 }
 
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
 func (t *tun) removeRoutes(routes []Route) error {
 	for _, r := range routes {
 		if !r.Install {

overlay/tun_ios.go

@@ -16,18 +16,41 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 )
 
 type tun struct {
-	io.ReadWriteCloser
+	rwc         io.ReadWriteCloser
 	vpnNetworks []netip.Prefix
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	l           *slog.Logger
 }
 
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) <= 4 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.rwc.Read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[4:n]
+	return 1, nil
+}
+
+func (t *tun) Write(p []byte) (int, error) {
+	return t.rwc.Write(p)
+}
+
+func (t *tun) Close() error {
+	return t.rwc.Close()
+}
+
 func newTun(_ *config.C, _ *slog.Logger, _ []netip.Prefix, _ bool) (*tun, error) {
 	return nil, fmt.Errorf("newTun not supported in iOS")
 }
@@ -35,9 +58,9 @@ func newTun(_ *config.C, _ *slog.Logger, _ []netip.Prefix, _ bool) (*tun, error)
 func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
 	file := os.NewFile(uintptr(deviceFd), "/dev/tun")
 	t := &tun{
-		vpnNetworks:     vpnNetworks,
-		ReadWriteCloser: &tunReadCloser{f: file},
-		l:               l,
+		vpnNetworks: vpnNetworks,
+		rwc:         &tunReadCloser{f: file},
+		l:           l,
 	}
 
 	err := t.reload(c, true)
@@ -96,18 +119,9 @@ type tunReadCloser struct {
 	wBuf []byte
 }
 
+// Read returns a packet with the BSD 4-byte header, watch out!
 func (tr *tunReadCloser) Read(to []byte) (int, error) {
-	tr.rMu.Lock()
-	defer tr.rMu.Unlock()
-
-	if cap(tr.rBuf) < len(to)+4 {
-		tr.rBuf = make([]byte, len(to)+4)
-	}
-	tr.rBuf = tr.rBuf[:len(to)+4]
-
-	n, err := tr.f.Read(tr.rBuf)
-	copy(to, tr.rBuf[4:])
-	return n - 4, err
+	return tr.f.Read(to)
 }
 
 func (tr *tunReadCloser) Write(from []byte) (int, error) {
@@ -155,6 +169,14 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for ios")
+func (t *tun) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for ios")
+}
+
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
 }

overlay/tun_linux.go

@@ -4,9 +4,7 @@
 package overlay
 
 import (
-	"encoding/binary"
 	"fmt"
-	"io"
 	"log/slog"
 	"net"
 	"net/netip"
@@ -19,180 +17,15 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
 	"github.com/vishvananda/netlink"
 	"golang.org/x/sys/unix"
 )
 
-// tunFile wraps a TUN file descriptor with poll-based reads. The FD provided will be changed to non-blocking.
-// A shared eventfd allows Close to wake all readers blocked in poll.
-type tunFile struct {
-	fd         int
-	shutdownFd int
-	lastOne    bool
-	readPoll   [2]unix.PollFd
-	writePoll  [2]unix.PollFd
-	closed     bool
-}
-
-// newFriend makes a tunFile for a MultiQueueReader that copies the shutdown eventfd from the parent tun
-func (r *tunFile) newFriend(fd int) (*tunFile, error) {
-	if err := unix.SetNonblock(fd, true); err != nil {
-		return nil, fmt.Errorf("failed to set tun fd non-blocking: %w", err)
-	}
-	return &tunFile{
-		fd:         fd,
-		shutdownFd: r.shutdownFd,
-		readPoll: [2]unix.PollFd{
-			{Fd: int32(fd), Events: unix.POLLIN},
-			{Fd: int32(r.shutdownFd), Events: unix.POLLIN},
-		},
-		writePoll: [2]unix.PollFd{
-			{Fd: int32(fd), Events: unix.POLLOUT},
-			{Fd: int32(r.shutdownFd), Events: unix.POLLIN},
-		},
-	}, nil
-}
-
-func newTunFd(fd int) (*tunFile, error) {
-	if err := unix.SetNonblock(fd, true); err != nil {
-		return nil, fmt.Errorf("failed to set tun fd non-blocking: %w", err)
-	}
-
-	shutdownFd, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
-	if err != nil {
-		return nil, fmt.Errorf("failed to create eventfd: %w", err)
-	}
-
-	out := &tunFile{
-		fd:         fd,
-		shutdownFd: shutdownFd,
-		lastOne:    true,
-		readPoll: [2]unix.PollFd{
-			{Fd: int32(fd), Events: unix.POLLIN},
-			{Fd: int32(shutdownFd), Events: unix.POLLIN},
-		},
-		writePoll: [2]unix.PollFd{
-			{Fd: int32(fd), Events: unix.POLLOUT},
-			{Fd: int32(shutdownFd), Events: unix.POLLIN},
-		},
-	}
-
-	return out, nil
-}
-
-func (r *tunFile) blockOnRead() error {
-	const problemFlags = unix.POLLHUP | unix.POLLNVAL | unix.POLLERR
-	var err error
-	for {
-		_, err = unix.Poll(r.readPoll[:], -1)
-		if err != unix.EINTR {
-			break
-		}
-	}
-	//always reset these!
-	tunEvents := r.readPoll[0].Revents
-	shutdownEvents := r.readPoll[1].Revents
-	r.readPoll[0].Revents = 0
-	r.readPoll[1].Revents = 0
-	//do the err check before trusting the potentially bogus bits we just got
-	if err != nil {
-		return err
-	}
-	if shutdownEvents&(unix.POLLIN|problemFlags) != 0 {
-		return os.ErrClosed
-	} else if tunEvents&problemFlags != 0 {
-		return os.ErrClosed
-	}
-	return nil
-}
-
-func (r *tunFile) blockOnWrite() error {
-	const problemFlags = unix.POLLHUP | unix.POLLNVAL | unix.POLLERR
-	var err error
-	for {
-		_, err = unix.Poll(r.writePoll[:], -1)
-		if err != unix.EINTR {
-			break
-		}
-	}
-	//always reset these!
-	tunEvents := r.writePoll[0].Revents
-	shutdownEvents := r.writePoll[1].Revents
-	r.writePoll[0].Revents = 0
-	r.writePoll[1].Revents = 0
-	//do the err check before trusting the potentially bogus bits we just got
-	if err != nil {
-		return err
-	}
-	if shutdownEvents&(unix.POLLIN|problemFlags) != 0 {
-		return os.ErrClosed
-	} else if tunEvents&problemFlags != 0 {
-		return os.ErrClosed
-	}
-	return nil
-}
-
-func (r *tunFile) Read(buf []byte) (int, error) {
-	for {
-		if n, err := unix.Read(r.fd, buf); err == nil {
-			return n, nil
-		} else if err == unix.EAGAIN {
-			if err = r.blockOnRead(); err != nil {
-				return 0, err
-			}
-			continue
-		} else if err == unix.EINTR {
-			continue
-		} else if err == unix.EBADF {
-			return 0, os.ErrClosed
-		} else {
-			return 0, err
-		}
-	}
-}
-
-func (r *tunFile) Write(buf []byte) (int, error) {
-	for {
-		if n, err := unix.Write(r.fd, buf); err == nil {
-			return n, nil
-		} else if err == unix.EAGAIN {
-			if err = r.blockOnWrite(); err != nil {
-				return 0, err
-			}
-			continue
-		} else if err == unix.EINTR {
-			continue
-		} else if err == unix.EBADF {
-			return 0, os.ErrClosed
-		} else {
-			return 0, err
-		}
-	}
-}
-
-func (r *tunFile) wakeForShutdown() error {
-	var buf [8]byte
-	binary.NativeEndian.PutUint64(buf[:], 1)
-	_, err := unix.Write(int(r.readPoll[1].Fd), buf[:])
-	return err
-}
-
-func (r *tunFile) Close() error {
-	if r.closed { // avoid closing more than once. Technically a fd could get re-used, which would be a problem
-		return nil
-	}
-	r.closed = true
-	if r.lastOne {
-		_ = unix.Close(r.shutdownFd)
-	}
-	return unix.Close(r.fd)
-}
-
 type tun struct {
-	*tunFile
-	readers     []*tunFile
+	readers     tio.QueueSet
 	closeLock   sync.Mutex
 	Device      string
 	vpnNetworks []netip.Prefix
@@ -239,7 +72,9 @@ type ifreqQLEN struct {
 }
 
 func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
-	t, err := newTunGeneric(c, l, deviceFd, vpnNetworks)
+	// We don't know what flags the caller opened this fd with and can't turn
+	// on IFF_VNET_HDR after TUNSETIFF, so skip offload on inherited fds.
+	t, err := newTunGeneric(c, l, deviceFd, false, false, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -249,46 +84,60 @@ func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip
 	return t, nil
 }
 
-func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
+// openTunDev opens /dev/net/tun, creating the device node first if it's
+// missing (docker containers occasionally omit it).
+func openTunDev() (int, 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)
-		if os.IsNotExist(err) {
-			err = os.MkdirAll("/dev/net", 0755)
-			if err != nil {
-				return nil, fmt.Errorf("/dev/net/tun doesn't exist, failed to mkdir -p /dev/net: %w", err)
-			}
-			err = unix.Mknod("/dev/net/tun", unix.S_IFCHR|0600, int(unix.Mkdev(10, 200)))
-			if err != nil {
-				return nil, fmt.Errorf("failed to create /dev/net/tun: %w", err)
-			}
-
-			fd, err = unix.Open("/dev/net/tun", os.O_RDWR, 0)
-			if err != nil {
-				return nil, fmt.Errorf("created /dev/net/tun, but still failed: %w", err)
-			}
-		} else {
-			return nil, err
-		}
+	if err == nil {
+		return fd, nil
 	}
+	if !os.IsNotExist(err) {
+		return -1, err
+	}
+	if err = os.MkdirAll("/dev/net", 0755); err != nil {
+		return -1, fmt.Errorf("/dev/net/tun doesn't exist, failed to mkdir -p /dev/net: %w", err)
+	}
+	if err = unix.Mknod("/dev/net/tun", unix.S_IFCHR|0600, int(unix.Mkdev(10, 200))); err != nil {
+		return -1, fmt.Errorf("failed to create /dev/net/tun: %w", err)
+	}
+	fd, err = unix.Open("/dev/net/tun", os.O_RDWR, 0)
+	if err != nil {
+		return -1, fmt.Errorf("created /dev/net/tun, but still failed: %w", err)
+	}
+	return fd, nil
+}
 
+// tunSetIff runs TUNSETIFF with the given flags and returns the kernel-chosen
+// device name on success.
+func tunSetIff(fd int, name string, flags uint16) (string, error) {
 	var req ifReq
-	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI)
+	req.Flags = flags
+	copy(req.Name[:], name)
+	if err := ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
+		return "", err
+	}
+	return strings.Trim(string(req.Name[:]), "\x00"), nil
+}
+
+func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, multiqueue bool) (*tun, error) {
+	baseFlags := uint16(unix.IFF_TUN | unix.IFF_NO_PI)
 	if multiqueue {
-		req.Flags |= unix.IFF_MULTI_QUEUE
+		baseFlags |= unix.IFF_MULTI_QUEUE
 	}
 	nameStr := c.GetString("tun.dev", "")
-	copy(req.Name[:], nameStr)
-	if err = ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
-		_ = unix.Close(fd)
-		return nil, &NameError{
-			Name:       nameStr,
-			Underlying: err,
-		}
-	}
-	name := strings.Trim(string(req.Name[:]), "\x00")
 
-	t, err := newTunGeneric(c, l, fd, vpnNetworks)
+	fd, err := openTunDev()
+	if err != nil {
+		return nil, err
+	}
+
+	name, err := tunSetIff(fd, nameStr, baseFlags)
+	if err != nil {
+		_ = unix.Close(fd)
+		return nil, &NameError{Name: nameStr, Underlying: err}
+	}
+
+	t, err := newTunGeneric(c, l, fd, false, false, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -299,15 +148,21 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, multiqueue
 }
 
 // newTunGeneric does all the stuff common to different tun initialization paths. It will close your files on error.
-func newTunGeneric(c *config.C, l *slog.Logger, fd int, vpnNetworks []netip.Prefix) (*tun, error) {
-	tfd, err := newTunFd(fd)
+func newTunGeneric(c *config.C, l *slog.Logger, fd int, vnetHdr, usoEnabled bool, vpnNetworks []netip.Prefix) (*tun, error) {
+	qs, err := tio.NewPollQueueSet()
+
 	if err != nil {
 		_ = unix.Close(fd)
 		return nil, err
 	}
+	err = qs.Add(fd)
+	if err != nil {
+		_ = unix.Close(fd)
+		return nil, err
+	}
+
 	t := &tun{
-		tunFile:                   tfd,
-		readers:                   []*tunFile{tfd},
+		readers:                   qs,
 		closeLock:                 sync.Mutex{},
 		vpnNetworks:               vpnNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
@@ -410,32 +265,29 @@ func (t *tun) SupportsMultiqueue() bool {
 	return true
 }
 
-func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+func (t *tun) NewMultiQueueReader() error {
 	t.closeLock.Lock()
 	defer t.closeLock.Unlock()
 
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	var req ifReq
-	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI | unix.IFF_MULTI_QUEUE)
-	copy(req.Name[:], t.Device)
-	if err = ioctl(uintptr(fd), uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&req))); err != nil {
+	flags := uint16(unix.IFF_TUN | unix.IFF_NO_PI | unix.IFF_MULTI_QUEUE)
+
+	if _, err = tunSetIff(fd, t.Device, flags); err != nil {
 		_ = unix.Close(fd)
-		return nil, err
+		return err
 	}
 
-	out, err := t.tunFile.newFriend(fd)
+	err = t.readers.Add(fd)
 	if err != nil {
 		_ = unix.Close(fd)
-		return nil, err
+		return err
 	}
 
-	t.readers = append(t.readers, out)
-
-	return out, nil
+	return nil
 }
 
 func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
@@ -603,6 +455,15 @@ func (t *tun) setDefaultRoute(cidr netip.Prefix) error {
 		Table:     unix.RT_TABLE_MAIN,
 		Type:      unix.RTN_UNICAST,
 	}
+	// Match the metric the kernel uses for its auto-installed connected
+	// route, so RouteReplace overwrites it in place instead of adding a
+	// second route at a worse metric. IPv6 connected routes are installed
+	// at metric 256 (IP6_RT_PRIO_KERN); IPv4 uses 0. Without this, the
+	// kernel route wins lookups and our MTU / AdvMSS / Features never
+	// apply on v6.
+	if cidr.Addr().Is6() {
+		nr.Priority = 256
+	}
 	err := netlink.RouteReplace(&nr)
 	if err != nil {
 		t.l.Warn("Failed to set default route MTU, retrying", "error", err, "cidr", cidr)
@@ -869,6 +730,10 @@ func (t *tun) updateRoutes(r netlink.RouteUpdate) {
 	t.routeTree.Store(newTree)
 }
 
+func (t *tun) Readers() []tio.Queue {
+	return t.readers.Queues()
+}
+
 func (t *tun) Close() error {
 	t.closeLock.Lock()
 	defer t.closeLock.Unlock()
@@ -878,32 +743,10 @@ func (t *tun) Close() error {
 		t.routeChan = nil
 	}
 
-	// Signal all readers blocked in poll to wake up and exit
-	_ = t.tunFile.wakeForShutdown()
-
 	if t.ioctlFd > 0 {
 		_ = unix.Close(int(t.ioctlFd))
 		t.ioctlFd = 0
 	}
 
-	for i := range t.readers {
-		if i == 0 {
-			continue //we want to close the zeroth reader last
-		}
-		err := t.readers[i].Close()
-		if err != nil {
-			t.l.Error("error closing tun reader", "reader", i, "error", err)
-		} else {
-			t.l.Info("closed tun reader", "reader", i)
-		}
-	}
-
-	//this is t.readers[0] too
-	err := t.tunFile.Close()
-	if err != nil {
-		t.l.Error("error closing tun reader", "reader", 0, "error", err)
-	} else {
-		t.l.Info("closed tun reader", "reader", 0)
-	}
-	return err
+	return t.readers.Close()
 }

overlay/tun_linux_test.go

@@ -3,7 +3,9 @@
 
 package overlay
 
-import "testing"
+import (
+	"testing"
+)
 
 var runAdvMSSTests = []struct {
 	name     string

overlay/tun_netbsd.go

@@ -6,7 +6,6 @@ package overlay
 import (
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -17,8 +16,10 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 	netroute "golang.org/x/net/route"
 	"golang.org/x/sys/unix"
 )
@@ -68,6 +69,27 @@ type tun struct {
 	fd          int
 }
 
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.readOne(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
 func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (*tun, error) {
@@ -141,7 +163,7 @@ func (t *tun) Close() error {
 	return nil
 }
 
-func (t *tun) Read(to []byte) (int, error) {
+func (t *tun) readOne(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)
@@ -394,8 +416,8 @@ 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) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for netbsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {

overlay/tun_openbsd.go

@@ -6,7 +6,6 @@ package overlay
 import (
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -17,8 +16,10 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
+	"github.com/slackhq/nebula/wire"
 	netroute "golang.org/x/net/route"
 	"golang.org/x/sys/unix"
 )
@@ -61,6 +62,19 @@ type tun struct {
 	out []byte
 }
 
+func (t *tun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) <= 4 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.f.Read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[4:n]
+	return 1, nil
+}
+
 var deviceNameRE = regexp.MustCompile(`^tun[0-9]+$`)
 
 func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (*tun, error) {
@@ -124,15 +138,6 @@ func (t *tun) Close() error {
 	return nil
 }
 
-func (t *tun) Read(to []byte) (int, error) {
-	buf := make([]byte, len(to)+4)
-
-	n, err := t.f.Read(buf)
-
-	copy(to, buf[4:])
-	return n - 4, err
-}
-
 // Write is only valid for single threaded use
 func (t *tun) Write(from []byte) (int, error) {
 	buf := t.out
@@ -314,8 +319,8 @@ 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) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for openbsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
@@ -366,6 +371,14 @@ func (t *tun) deviceBytes() (o [16]byte) {
 	return
 }
 
+func (t *tun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *tun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
 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 {

overlay/tun_tester.go

@@ -14,8 +14,10 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/udp"
+	"github.com/slackhq/nebula/wire"
 )
 
 type TestTun struct {
@@ -162,7 +164,20 @@ func (t *TestTun) Close() error {
 	return nil
 }
 
-func (t *TestTun) Read(b []byte) (int, error) {
+func (t *TestTun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
+func (t *TestTun) read(b []byte) (int, error) {
 	p, ok := <-t.rxPackets
 	if !ok {
 		return 0, os.ErrClosed
@@ -177,10 +192,18 @@ func (t *TestTun) Read(b []byte) (int, error) {
 	return n, nil
 }
 
+func (t *TestTun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *TestTun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
 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) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented")
 }

overlay/tun_windows.go

@@ -6,7 +6,6 @@ package overlay
 import (
 	"crypto"
 	"fmt"
-	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -18,9 +17,11 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
 	"github.com/slackhq/nebula/util"
 	"github.com/slackhq/nebula/wintun"
+	"github.com/slackhq/nebula/wire"
 	"golang.org/x/sys/windows"
 	"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
 )
@@ -47,6 +48,19 @@ type winTun struct {
 	tun *wintun.NativeTun
 }
 
+func (t *winTun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := t.tun.Read(mem, 0)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
 func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (Device, error) {
 	return nil, fmt.Errorf("newTunFromFd not supported in Windows")
 }
@@ -255,10 +269,6 @@ func (t *winTun) Name() string {
 	return t.Device
 }
 
-func (t *winTun) Read(b []byte) (int, error) {
-	return t.tun.Read(b, 0)
-}
-
 func (t *winTun) Write(b []byte) (int, error) {
 	return t.tun.Write(b, 0)
 }
@@ -267,8 +277,16 @@ func (t *winTun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *winTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
+func (t *winTun) NewMultiQueueReader() error {
+	return fmt.Errorf("TODO: multiqueue not implemented for windows")
+}
+
+func (t *winTun) Readers() []tio.Queue {
+	return []tio.Queue{t}
+}
+
+func (t *winTun) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
 }
 
 func (t *winTun) Close() error {

overlay/user.go

@@ -6,7 +6,9 @@ import (
 	"net/netip"
 
 	"github.com/slackhq/nebula/config"
+	"github.com/slackhq/nebula/overlay/tio"
 	"github.com/slackhq/nebula/routing"
+	"github.com/slackhq/nebula/wire"
 )
 
 func NewUserDeviceFromConfig(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, routines int) (Device, error) {
@@ -23,11 +25,13 @@ func NewUserDevice(vpnNetworks []netip.Prefix) (Device, error) {
 		outboundWriter: ow,
 		inboundReader:  ir,
 		inboundWriter:  iw,
+		numReaders:     1,
 	}, nil
 }
 
 type UserDevice struct {
 	vpnNetworks []netip.Prefix
+	numReaders  int
 
 	outboundReader *io.PipeReader
 	outboundWriter *io.PipeWriter
@@ -36,6 +40,23 @@ type UserDevice struct {
 	inboundWriter *io.PipeWriter
 }
 
+func (d *UserDevice) Capabilities() tio.Capabilities {
+	return tio.Capabilities{}
+}
+
+func (d *UserDevice) Read(p []wire.TunPacket, mem []byte) (int, error) {
+	if len(p) == 0 || len(mem) == 0 {
+		return 0, nil //todo should this be an err?
+	}
+	p[0].Meta = struct{}{}
+	n, err := d.outboundReader.Read(mem)
+	if err != nil {
+		return 0, err
+	}
+	p[0].Bytes = mem[:n]
+	return 1, nil
+}
+
 func (d *UserDevice) Activate() error {
 	return nil
 }
@@ -50,20 +71,27 @@ func (d *UserDevice) SupportsMultiqueue() bool {
 	return true
 }
 
-func (d *UserDevice) NewMultiQueueReader() (io.ReadWriteCloser, error) {
-	return d, nil
+func (d *UserDevice) NewMultiQueueReader() error {
+	d.numReaders++
+	return nil
+}
+
+func (d *UserDevice) Readers() []tio.Queue {
+	out := make([]tio.Queue, d.numReaders)
+	for i := range d.numReaders {
+		out[i] = d
+	}
+	return out
 }
 
 func (d *UserDevice) Pipe() (*io.PipeReader, *io.PipeWriter) {
 	return d.inboundReader, d.outboundWriter
 }
 
-func (d *UserDevice) Read(p []byte) (n int, err error) {
-	return d.outboundReader.Read(p)
-}
 func (d *UserDevice) Write(p []byte) (n int, err error) {
 	return d.inboundWriter.Write(p)
 }
+
 func (d *UserDevice) Close() error {
 	d.inboundWriter.Close()
 	d.outboundWriter.Close()

relay_manager.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"log/slog"
 	"net/netip"
-	"slices"
 	"sync/atomic"
 
 	"github.com/slackhq/nebula/cert"
@@ -58,25 +57,14 @@ func (rm *relayManager) GetUseRelays() bool {
 // For each candidate relay it either kicks off a handshake to the relay, sends a CreateRelayRequest, retransmits
 // one that may have been lost, or, once the relay is Established, forwards the in-progress
 // stage 0 handshake packet for vpnIp through it.
-func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *HandshakeHostInfo, stage0 []byte) {
-	hostinfo := hh.hostinfo
+func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hostinfo *HostInfo, stage0 []byte) {
 	if !rm.GetUseRelays() || len(hostinfo.remotes.relays) == 0 {
-		hh.lastRelays = nil
 		return
 	}
 
-	relays := hostinfo.remotes.relays
-	listLevel := slog.LevelDebug
-	prior := hh.lastRelays
-	if !slices.Equal(relays, prior) {
-		listLevel = slog.LevelInfo
-		hh.lastRelays = slices.Clone(relays)
-	}
-	hl := hostinfo.logger(rm.l)
-	hl.Log(context.Background(), listLevel, "Attempt to relay through hosts", "relays", relays)
-
+	hostinfo.logger(rm.l).Info("Attempt to relay through hosts", "relays", hostinfo.remotes.relays)
 	// Send a RelayRequest to all known Relay IP's
-	for _, relay := range relays {
+	for _, relay := range hostinfo.remotes.relays {
 		// Don't relay through the host I'm trying to connect to
 		if relay == vpnIp {
 			continue
@@ -87,19 +75,12 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 			continue
 		}
 
-		// Each relay's per-attempt log fires at Info on the first time we hit it and Debug after that.
-		level := slog.LevelInfo
-		if slices.Contains(prior, relay) {
-			level = slog.LevelDebug
-		}
-
 		relayHostInfo := rm.hostmap.QueryVpnAddr(relay)
 		if relayHostInfo == nil || !relayHostInfo.remote.IsValid() {
-			hl.Log(context.Background(), level, "Establish tunnel to relay target", "relay", relay.String())
+			hostinfo.logger(rm.l).Info("Establish tunnel to relay target", "relay", relay.String())
 			f.Handshake(relay)
 			continue
 		}
-
 		// Check the relay HostInfo to see if we already established a relay through
 		existingRelay, ok := relayHostInfo.relayState.QueryRelayForByIp(vpnIp)
 		if !ok {
@@ -107,7 +88,7 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 			if relayHostInfo.remote.IsValid() {
 				idx, err := AddRelay(rm.l, relayHostInfo, rm.hostmap, vpnIp, nil, TerminalType, Requested)
 				if err != nil {
-					hl.Info("Failed to add relay to hostmap", "relay", relay.String(), "error", err)
+					hostinfo.logger(rm.l).Info("Failed to add relay to hostmap", "relay", relay.String(), "error", err)
 				}
 
 				m := NebulaControl{
@@ -118,12 +99,12 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 				switch relayHostInfo.GetCert().Certificate.Version() {
 				case cert.Version1:
 					if !f.myVpnAddrs[0].Is4() {
-						hl.Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
+						hostinfo.logger(rm.l).Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
 						continue
 					}
 
 					if !vpnIp.Is4() {
-						hl.Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
+						hostinfo.logger(rm.l).Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
 						continue
 					}
 
@@ -135,16 +116,16 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 					m.RelayFromAddr = netAddrToProtoAddr(f.myVpnAddrs[0])
 					m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 				default:
-					hl.Error("Unknown certificate version found while creating relay")
+					hostinfo.logger(rm.l).Error("Unknown certificate version found while creating relay")
 					continue
 				}
 
 				msg, err := m.Marshal()
 				if err != nil {
-					hl.Error("Failed to marshal Control message to create relay", "error", err)
+					hostinfo.logger(rm.l).Error("Failed to marshal Control message to create relay", "error", err)
 				} else {
 					f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
-					rm.l.Log(context.Background(), level, "send CreateRelayRequest",
+					rm.l.Info("send CreateRelayRequest",
 						"relayFrom", f.myVpnAddrs[0],
 						"relayTo", vpnIp,
 						"initiatorRelayIndex", idx,
@@ -157,14 +138,14 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 
 		switch existingRelay.State {
 		case Established:
-			hl.Log(context.Background(), level, "Send handshake via relay", "relay", relay.String())
+			hostinfo.logger(rm.l).Info("Send handshake via relay", "relay", relay.String())
 			f.SendVia(relayHostInfo, existingRelay, stage0, make([]byte, 12), make([]byte, mtu), false)
 		case Disestablished:
 			// Mark this relay as 'requested'
 			relayHostInfo.relayState.UpdateRelayForByIpState(vpnIp, Requested)
 			fallthrough
 		case Requested:
-			hl.Log(context.Background(), level, "Re-send CreateRelay request", "relay", relay.String())
+			hostinfo.logger(rm.l).Info("Re-send CreateRelay request", "relay", relay.String())
 			// Re-send the CreateRelay request, in case the previous one was lost.
 			m := NebulaControl{
 				Type:                NebulaControl_CreateRelayRequest,
@@ -174,12 +155,12 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 			switch relayHostInfo.GetCert().Certificate.Version() {
 			case cert.Version1:
 				if !f.myVpnAddrs[0].Is4() {
-					hl.Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
+					hostinfo.logger(rm.l).Error("can not establish v1 relay with a v6 network because the relay is not running a current nebula version")
 					continue
 				}
 
 				if !vpnIp.Is4() {
-					hl.Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
+					hostinfo.logger(rm.l).Error("can not establish v1 relay with a v6 remote network because the relay is not running a current nebula version")
 					continue
 				}
 
@@ -191,16 +172,16 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 				m.RelayFromAddr = netAddrToProtoAddr(f.myVpnAddrs[0])
 				m.RelayToAddr = netAddrToProtoAddr(vpnIp)
 			default:
-				hl.Error("Unknown certificate version found while creating relay")
+				hostinfo.logger(rm.l).Error("Unknown certificate version found while creating relay")
 				continue
 			}
 			msg, err := m.Marshal()
 			if err != nil {
-				hl.Error("Failed to marshal Control message to create relay", "error", err)
+				hostinfo.logger(rm.l).Error("Failed to marshal Control message to create relay", "error", err)
 			} else {
 				// This must send over the hostinfo, not over hm.Hosts[ip]
 				f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, make([]byte, 12), make([]byte, mtu))
-				rm.l.Log(context.Background(), level, "send CreateRelayRequest",
+				rm.l.Info("send CreateRelayRequest",
 					"relayFrom", f.myVpnAddrs[0],
 					"relayTo", vpnIp,
 					"initiatorRelayIndex", existingRelay.LocalIndex,
@@ -211,7 +192,7 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hh *Handshak
 			// PeerRequested only occurs in Forwarding relays, not Terminal relays, and this is a Terminal relay case.
 			fallthrough
 		default:
-			hl.Error("Relay unexpected state",
+			hostinfo.logger(rm.l).Error("Relay unexpected state",
 				"vpnIp", vpnIp,
 				"state", existingRelay.State,
 				"relay", relay,
@@ -318,16 +299,17 @@ func (rm *relayManager) HandleControlMsg(h *HostInfo, d []byte, f *Interface) {
 }
 
 func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f *Interface, m *NebulaControl) {
-	relayFrom := protoAddrToNetAddr(m.RelayFromAddr)
-	relayTo := protoAddrToNetAddr(m.RelayToAddr)
 	rm.l.Info("handleCreateRelayResponse",
-		"relayFrom", relayFrom,
-		"relayTo", relayTo,
+		"relayFrom", protoAddrToNetAddr(m.RelayFromAddr),
+		"relayTo", protoAddrToNetAddr(m.RelayToAddr),
 		"initiatorRelayIndex", m.InitiatorRelayIndex,
 		"responderRelayIndex", m.ResponderRelayIndex,
 		"vpnAddrs", h.vpnAddrs,
 	)
 
+	target := m.RelayToAddr
+	targetAddr := protoAddrToNetAddr(target)
+
 	relay, err := rm.EstablishRelay(h, m)
 	if err != nil {
 		rm.l.Error("Failed to update relay for relayTo", "error", err)
@@ -343,7 +325,7 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 		rm.l.Error("Can't find a HostInfo for peer", "relayTo", relay.PeerAddr)
 		return
 	}
-	peerRelay, ok := peerHostInfo.relayState.QueryRelayForByIp(relayTo)
+	peerRelay, ok := peerHostInfo.relayState.QueryRelayForByIp(targetAddr)
 	if !ok {
 		rm.l.Error("peerRelay does not have Relay state for relayTo", "relayTo", peerHostInfo.vpnAddrs[0])
 		return
@@ -353,19 +335,19 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 		// I initiated the request to this peer, but haven't heard back from the peer yet. I must wait for this peer
 		// to respond to complete the connection.
 	case PeerRequested, Disestablished, Established:
-		peerHostInfo.relayState.UpdateRelayForByIpState(relayTo, Established)
+		peerHostInfo.relayState.UpdateRelayForByIpState(targetAddr, Established)
 		resp := NebulaControl{
 			Type:                NebulaControl_CreateRelayResponse,
 			ResponderRelayIndex: peerRelay.LocalIndex,
 			InitiatorRelayIndex: peerRelay.RemoteIndex,
 		}
 
-		peer := peerHostInfo.vpnAddrs[0]
 		if v == cert.Version1 {
+			peer := peerHostInfo.vpnAddrs[0]
 			if !peer.Is4() {
 				rm.l.Error("Refusing to CreateRelayResponse for a v1 relay with an ipv6 address",
 					"relayFrom", peer,
-					"relayTo", relayTo,
+					"relayTo", target,
 					"initiatorRelayIndex", resp.InitiatorRelayIndex,
 					"responderRelayIndex", resp.ResponderRelayIndex,
 					"vpnAddrs", peerHostInfo.vpnAddrs,
@@ -375,26 +357,26 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 
 			b := peer.As4()
 			resp.OldRelayFromAddr = binary.BigEndian.Uint32(b[:])
-			b = relayTo.As4()
+			b = targetAddr.As4()
 			resp.OldRelayToAddr = binary.BigEndian.Uint32(b[:])
 		} else {
-			resp.RelayFromAddr = netAddrToProtoAddr(peer)
-			resp.RelayToAddr = m.RelayToAddr
+			resp.RelayFromAddr = netAddrToProtoAddr(peerHostInfo.vpnAddrs[0])
+			resp.RelayToAddr = target
 		}
 
 		msg, err := resp.Marshal()
 		if err != nil {
 			rm.l.Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay", "error", err)
-			return
+		} else {
+			f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, make([]byte, 12), make([]byte, mtu))
+			rm.l.Info("send CreateRelayResponse",
+				"relayFrom", resp.RelayFromAddr,
+				"relayTo", resp.RelayToAddr,
+				"initiatorRelayIndex", resp.InitiatorRelayIndex,
+				"responderRelayIndex", resp.ResponderRelayIndex,
+				"vpnAddrs", peerHostInfo.vpnAddrs,
+			)
 		}
-		f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, make([]byte, 12), make([]byte, mtu))
-		rm.l.Info("send CreateRelayResponse",
-			"relayFrom", peer,
-			"relayTo", relayTo,
-			"initiatorRelayIndex", resp.InitiatorRelayIndex,
-			"responderRelayIndex", resp.ResponderRelayIndex,
-			"vpnAddrs", peerHostInfo.vpnAddrs,
-		)
 	}
 }
 

relay_manager_test.go

@@ -1,97 +0,0 @@
-package nebula
-
-import (
-	"bytes"
-	"log/slog"
-	"net/netip"
-	"testing"
-
-	"github.com/gaissmai/bart"
-	"github.com/slackhq/nebula/test"
-	"github.com/stretchr/testify/assert"
-)
-
-// TestStartRelaysLogDedupe verifies that repeated attempts with the same relay set drop the log
-// chatter to Debug, mirroring how the normal handshake retry loop quiets down once it's already
-// announced its targets.
-func TestStartRelaysLogDedupe(t *testing.T) {
-	vpnIp := netip.MustParseAddr("100.64.99.4")
-	otherRelay := netip.MustParseAddr("100.64.99.5")
-
-	newHH := func() *HandshakeHostInfo {
-		// Use the target's own vpnIp as the "relay" so the loop body skips it without
-		// touching any sender-side state. That isolates the test to the level-selection
-		// behavior of the top-level "Attempt to relay through hosts" log.
-		hostinfo := &HostInfo{
-			vpnAddrs:     []netip.Addr{vpnIp},
-			localIndexId: 1,
-			remotes:      NewRemoteList([]netip.Addr{vpnIp}, nil),
-		}
-		hostinfo.remotes.relays = []netip.Addr{vpnIp}
-		return &HandshakeHostInfo{hostinfo: hostinfo}
-	}
-
-	// Park any extra relay addresses we'll introduce mid-test in myVpnAddrsTable so the loop
-	// body always skips before touching f.Handshake (which would need a real handshakeManager).
-	addrTable := new(bart.Lite)
-	addrTable.Insert(netip.PrefixFrom(otherRelay, otherRelay.BitLen()))
-	f := &Interface{myVpnAddrsTable: addrTable}
-
-	newRM := func(buf *bytes.Buffer) *relayManager {
-		l := test.NewLoggerWithOutputAndLevel(buf, slog.LevelDebug)
-		rm := &relayManager{l: l, hostmap: newHostMap(l)}
-		rm.useRelays.Store(true)
-		return rm
-	}
-
-	const msg = `msg="Attempt to relay through hosts"`
-
-	t.Run("first attempt logs at Info", func(t *testing.T) {
-		var buf bytes.Buffer
-		rm := newRM(&buf)
-		hh := newHH()
-		rm.StartRelays(f, vpnIp, hh, nil)
-		assert.Equal(t, []netip.Addr{vpnIp}, hh.lastRelays, "lastRelays should record the relay set we just attempted")
-		assert.Contains(t, buf.String(), "level=INFO "+msg, "expected Info level on first attempt")
-	})
-
-	t.Run("repeat attempt with same relays drops to Debug", func(t *testing.T) {
-		var buf bytes.Buffer
-		rm := newRM(&buf)
-		hh := newHH()
-		rm.StartRelays(f, vpnIp, hh, nil)
-		first := append([]netip.Addr(nil), hh.lastRelays...)
-		buf.Reset()
-		rm.StartRelays(f, vpnIp, hh, nil)
-		assert.Equal(t, first, hh.lastRelays)
-		assert.Contains(t, buf.String(), "level=DEBUG "+msg, "expected Debug level on identical retry")
-		assert.NotContains(t, buf.String(), "level=INFO "+msg, "Info should not fire on identical retry")
-	})
-
-	t.Run("changed relay list bumps back to Info", func(t *testing.T) {
-		var buf bytes.Buffer
-		rm := newRM(&buf)
-		hh := newHH()
-		rm.StartRelays(f, vpnIp, hh, nil)
-		buf.Reset()
-
-		// The lighthouse handed us a new set this round.
-		hh.hostinfo.remotes.relays = []netip.Addr{vpnIp, otherRelay}
-
-		rm.StartRelays(f, vpnIp, hh, nil)
-		assert.Equal(t, []netip.Addr{vpnIp, otherRelay}, hh.lastRelays)
-		assert.Contains(t, buf.String(), "level=INFO "+msg, "expected Info when the relay list changes")
-	})
-
-	t.Run("disabled relays clears lastRelays and emits no Attempt log", func(t *testing.T) {
-		var buf bytes.Buffer
-		rm := newRM(&buf)
-		rm.useRelays.Store(false)
-		hh := newHH()
-		hh.lastRelays = []netip.Addr{vpnIp}
-
-		rm.StartRelays(f, vpnIp, hh, nil)
-		assert.Nil(t, hh.lastRelays, "with relays disabled lastRelays should be cleared")
-		assert.NotContains(t, buf.String(), msg, "should not log when we shortcut out")
-	})
-}

remote_list.go

@@ -239,31 +239,6 @@ func (r *RemoteList) unlockedSetHostnamesResults(hr *hostnamesResults) {
 	r.hr = hr
 }
 
-// ResetForOwner zeros the reported address slices for the given owner and marks the addrs list dirty.
-// Any pending hostname resolution will be canceled.
-func (r *RemoteList) ResetForOwner(ownerVpnAddr netip.Addr) {
-	r.Lock()
-	defer r.Unlock()
-	r.hr.Cancel()
-	if c, ok := r.cache[ownerVpnAddr]; ok {
-		if c.v4 != nil {
-			c.v4.reported = c.v4.reported[:0]
-		}
-		if c.v6 != nil {
-			c.v6.reported = c.v6.reported[:0]
-		}
-	}
-	r.shouldRebuild = true
-}
-
-// ClearHostnameResults cancels the in-flight DNS resolver goroutine (if any) and drops the resolved IP cache.
-func (r *RemoteList) ClearHostnameResults() {
-	r.Lock()
-	defer r.Unlock()
-	r.unlockedSetHostnamesResults(nil)
-	r.shouldRebuild = true
-}
-
 // Len locks and reports the size of the deduplicated address list
 // The deduplication work may need to occur here, so you must pass preferredRanges
 func (r *RemoteList) Len(preferredRanges []netip.Prefix) int {

remote_list_test.go

@@ -6,22 +6,8 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
-// trackedHostnameResults builds a *hostnamesResults with a known cancel function and a
-// pre-populated ips map so tests can assert cancellation and verify previously-resolved
-// IPs survive a cancel without spinning up a real DNS resolver.
-func trackedHostnameResults(cancelFn func(), addrs ...string) *hostnamesResults {
-	hr := &hostnamesResults{cancelFn: cancelFn}
-	ips := map[netip.AddrPort]struct{}{}
-	for _, a := range addrs {
-		ips[netip.MustParseAddrPort(a)] = struct{}{}
-	}
-	hr.ips.Store(&ips)
-	return hr
-}
-
 func TestRemoteList_Rebuild(t *testing.T) {
 	rl := NewRemoteList([]netip.Addr{netip.MustParseAddr("0.0.0.0")}, nil)
 	rl.unlockedSetV4(
@@ -126,81 +112,6 @@ func TestRemoteList_Rebuild(t *testing.T) {
 	assert.Equal(t, "172.31.0.1:10101", rl.addrs[9].String())
 }
 
-func TestRemoteList_ResetForOwner(t *testing.T) {
-	ourselves := netip.MustParseAddr("10.0.0.1")
-	otherOwner := netip.MustParseAddr("10.0.0.2")
-	vpnAddr := netip.MustParseAddr("10.0.0.99")
-
-	rl := NewRemoteList([]netip.Addr{vpnAddr}, nil)
-	rl.unlockedSetV4(ourselves, vpnAddr,
-		[]*V4AddrPort{newIp4AndPortFromString("1.1.1.1:4242")},
-		func(netip.Addr, *V4AddrPort) bool { return true },
-	)
-	rl.unlockedSetV6(ourselves, vpnAddr,
-		[]*V6AddrPort{newIp6AndPortFromString("[1::1]:4242")},
-		func(netip.Addr, *V6AddrPort) bool { return true },
-	)
-	rl.unlockedSetV4(otherOwner, vpnAddr,
-		[]*V4AddrPort{newIp4AndPortFromString("2.2.2.2:4242")},
-		func(netip.Addr, *V4AddrPort) bool { return true },
-	)
-
-	canceled := 0
-	hr := trackedHostnameResults(func() { canceled++ }, "3.3.3.3:4242")
-	rl.Lock()
-	rl.unlockedSetHostnamesResults(hr)
-	rl.Unlock()
-
-	rl.ResetForOwner(ourselves)
-
-	rl.RLock()
-	defer rl.RUnlock()
-	assert.Empty(t, rl.cache[ourselves].v4.reported, "our v4 reported should be cleared")
-	assert.Empty(t, rl.cache[ourselves].v6.reported, "our v6 reported should be cleared")
-	assert.Len(t, rl.cache[otherOwner].v4.reported, 1, "other owner's contribution must be preserved")
-	assert.Equal(t, "2.2.2.2:4242", protoV4AddrPortToNetAddrPort(rl.cache[otherOwner].v4.reported[0]).String())
-	assert.Equal(t, 1, canceled, "DNS resolution goroutine should be canceled")
-	assert.Same(t, hr, rl.hr, "hostnamesResults must be preserved so DNS-resolved IPs keep feeding addrs until replaced")
-	assert.NotEmpty(t, rl.hr.GetAddrs(), "previously-resolved IPs should still be readable after cancel")
-	assert.True(t, rl.shouldRebuild, "shouldRebuild must be set so the next Rebuild recomputes addrs")
-}
-
-func TestRemoteList_ResetForOwner_NoEntry(t *testing.T) {
-	// An owner with no cache entry must not panic; shouldRebuild is still set and any
-	// existing hostnamesResults is canceled.
-	rl := NewRemoteList([]netip.Addr{netip.MustParseAddr("10.0.0.99")}, nil)
-	canceled := 0
-	rl.Lock()
-	rl.unlockedSetHostnamesResults(trackedHostnameResults(func() { canceled++ }, "3.3.3.3:4242"))
-	rl.Unlock()
-
-	rl.ResetForOwner(netip.MustParseAddr("10.0.0.1"))
-
-	rl.RLock()
-	defer rl.RUnlock()
-	assert.Equal(t, 1, canceled)
-	assert.True(t, rl.shouldRebuild)
-}
-
-func TestRemoteList_ClearHostnameResults(t *testing.T) {
-	rl := NewRemoteList([]netip.Addr{netip.MustParseAddr("10.0.0.99")}, nil)
-
-	canceled := 0
-	hr := trackedHostnameResults(func() { canceled++ }, "3.3.3.3:4242")
-	rl.Lock()
-	rl.unlockedSetHostnamesResults(hr)
-	rl.Unlock()
-	require.NotEmpty(t, hr.GetAddrs(), "hostnamesResults should have its fastrack IPs populated")
-
-	rl.ClearHostnameResults()
-
-	rl.RLock()
-	defer rl.RUnlock()
-	assert.Equal(t, 1, canceled, "DNS resolution goroutine should be canceled")
-	assert.Nil(t, rl.hr, "hostnamesResults should be dropped")
-	assert.True(t, rl.shouldRebuild)
-}
-
 func BenchmarkFullRebuild(b *testing.B) {
 	rl := NewRemoteList([]netip.Addr{netip.MustParseAddr("0.0.0.0")}, nil)
 	rl.unlockedSetV4(

stats.go

@@ -331,7 +331,7 @@ func loadStatsConfig(c *config.C) (statsConfig, error) {
 	}
 
 	cfg.interval = c.GetDuration("stats.interval", 0)
-	if cfg.interval <= 0 {
+	if cfg.interval == 0 {
 		return cfg, fmt.Errorf("stats.interval was an invalid duration: %s", c.GetString("stats.interval", ""))
 	}
 

udp/conn.go

@@ -8,16 +8,49 @@ import (
 
 const MTU = 9001
 
+// MaxWriteBatch is the largest batch any Conn.WriteBatch implementation is
+// required to accept. Callers SHOULD NOT pass more than this per call; Linux
+// backends preallocate sendmmsg scratch sized to this value, so exceeding it
+// only costs additional sendmmsg chunks within a single WriteBatch call.
+const MaxWriteBatch = 128
+
+// RxMeta carries per-packet metadata extracted from the RX path (ancillary
+// data, kernel offload state, etc.) and passed to EncReader callbacks.
+// Backends that do not produce a particular signal leave its zero value.
+//
+// OuterECN is the 2-bit IP-level ECN codepoint stamped on the carrier
+// datagram (extracted from IP_TOS / IPV6_TCLASS cmsg on Linux). Zero
+// means Not-ECT, which is also the value backends without ECN RX support
+// supply on every packet.
+type RxMeta struct {
+	OuterECN byte
+}
+
 type EncReader func(
 	addr netip.AddrPort,
 	payload []byte,
+	meta RxMeta,
 )
 
 type Conn interface {
 	Rebind() error
 	LocalAddr() (netip.AddrPort, error)
-	ListenOut(r EncReader) error
+	// ListenOut invokes r for each received packet. On batch-capable
+	// backends (recvmmsg), flush is called after each batch is fully
+	// delivered — callers use it to flush per-batch accumulators such as
+	// TUN write coalescers. Single-packet backends call flush after each
+	// packet. flush must not be nil.
+	ListenOut(r EncReader, flush func()) error
 	WriteTo(b []byte, addr netip.AddrPort) error
+	// WriteBatch sends a contiguous batch of packets, each with its own
+	// destination. bufs and addrs must have the same length. outerECNs may
+	// be nil (treated as all-zero / Not-ECT); when non-nil it must have the
+	// same length as bufs, and outerECNs[i] is the 2-bit IP-level ECN
+	// codepoint to set on packet i's outer header. Linux uses sendmmsg(2)
+	// for a single syscall and attaches the value as IP_TOS / IPV6_TCLASS
+	// cmsg; other backends ignore it. Returns on the first error; callers
+	// may observe a partial send if some packets went out before the error.
+	WriteBatch(bufs [][]byte, addrs []netip.AddrPort, outerECNs []byte) error
 	ReloadConfig(c *config.C)
 	SupportsMultipleReaders() bool
 	Close() error
@@ -31,7 +64,7 @@ func (NoopConn) Rebind() error {
 func (NoopConn) LocalAddr() (netip.AddrPort, error) {
 	return netip.AddrPort{}, nil
 }
-func (NoopConn) ListenOut(_ EncReader) error {
+func (NoopConn) ListenOut(_ EncReader, _ func()) error {
 	return nil
 }
 func (NoopConn) SupportsMultipleReaders() bool {
@@ -40,6 +73,9 @@ func (NoopConn) SupportsMultipleReaders() bool {
 func (NoopConn) WriteTo(_ []byte, _ netip.AddrPort) error {
 	return nil
 }
+func (NoopConn) WriteBatch(_ [][]byte, _ []netip.AddrPort, _ []byte) error {
+	return nil
+}
 func (NoopConn) ReloadConfig(_ *config.C) {
 	return
 }

udp/udp_darwin.go

@@ -140,6 +140,15 @@ func (u *StdConn) WriteTo(b []byte, ap netip.AddrPort) error {
 	}
 }
 
+func (u *StdConn) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, _ []byte) error {
+	for i, b := range bufs {
+		if err := u.WriteTo(b, addrs[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (u *StdConn) LocalAddr() (netip.AddrPort, error) {
 	a := u.UDPConn.LocalAddr()
 
@@ -165,7 +174,7 @@ func NewUDPStatsEmitter(udpConns []Conn) func() {
 	return func() {}
 }
 
-func (u *StdConn) ListenOut(r EncReader) error {
+func (u *StdConn) ListenOut(r EncReader, flush func()) error {
 	buffer := make([]byte, MTU)
 
 	for {
@@ -175,11 +184,12 @@ func (u *StdConn) ListenOut(r EncReader) error {
 			if errors.Is(err, net.ErrClosed) {
 				return err
 			}
+
 			u.l.Error("unexpected udp socket receive error", "error", err)
-			continue
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], RxMeta{})
+		flush()
 	}
 }
 

udp/udp_generic.go

@@ -44,6 +44,15 @@ func (u *GenericConn) WriteTo(b []byte, addr netip.AddrPort) error {
 	return err
 }
 
+func (u *GenericConn) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, _ []byte) error {
+	for i, b := range bufs {
+		if _, err := u.UDPConn.WriteToUDPAddrPort(b, addrs[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (u *GenericConn) LocalAddr() (netip.AddrPort, error) {
 	a := u.UDPConn.LocalAddr()
 
@@ -73,7 +82,7 @@ type rawMessage struct {
 	Len uint32
 }
 
-func (u *GenericConn) ListenOut(r EncReader) error {
+func (u *GenericConn) ListenOut(r EncReader, flush func()) error {
 	buffer := make([]byte, MTU)
 
 	var lastRecvErr time.Time
@@ -93,7 +102,8 @@ func (u *GenericConn) ListenOut(r EncReader) error {
 			continue
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], RxMeta{})
+		flush()
 	}
 }
 

udp/udp_linux.go

@@ -24,6 +24,22 @@ type StdConn struct {
 	isV4    bool
 	l       *slog.Logger
 	batch   int
+
+	// sendmmsg scratch. Each queue has its own StdConn, so no locking is
+	// needed. Sized to MaxWriteBatch at construction; WriteBatch chunks
+	// larger inputs.
+	writeMsgs  []rawMessage
+	writeIovs  []iovec
+	writeNames [][]byte
+
+	// sendmmsg(2) callback state. sendmmsgCB is bound once in NewListener
+	// to the sendmmsgRun method value so passing it to rawConn.Write does
+	// not allocate a fresh closure per send; sendmmsgN/Sent/Errno carry
+	// the inputs and outputs across the call without escaping locals.
+	sendmmsgCB    func(fd uintptr) bool
+	sendmmsgN     int
+	sendmmsgSent  int
+	sendmmsgErrno syscall.Errno
 }
 
 func setReusePort(network, address string, c syscall.RawConn) error {
@@ -70,9 +86,23 @@ func NewListener(l *slog.Logger, ip netip.Addr, port int, multi bool, batch int)
 	}
 	out.isV4 = af == unix.AF_INET
 
+	out.prepareWriteMessages(MaxWriteBatch)
+	out.sendmmsgCB = out.sendmmsgRun
+
 	return out, nil
 }
 
+func (u *StdConn) prepareWriteMessages(n int) {
+	u.writeMsgs = make([]rawMessage, n)
+	u.writeIovs = make([]iovec, n)
+	u.writeNames = make([][]byte, n)
+
+	for i := range u.writeMsgs {
+		u.writeNames[i] = make([]byte, unix.SizeofSockaddrInet6)
+		u.writeMsgs[i].Hdr.Name = &u.writeNames[i][0]
+	}
+}
+
 func (u *StdConn) SupportsMultipleReaders() bool {
 	return true
 }
@@ -171,7 +201,7 @@ func recvmmsg(fd uintptr, msgs []rawMessage) (int, bool, error) {
 	return int(n), true, nil
 }
 
-func (u *StdConn) listenOutSingle(r EncReader) error {
+func (u *StdConn) listenOutSingle(r EncReader, flush func()) error {
 	var err error
 	var n int
 	var from netip.AddrPort
@@ -183,16 +213,33 @@ func (u *StdConn) listenOutSingle(r EncReader) error {
 			return err
 		}
 		from = netip.AddrPortFrom(from.Addr().Unmap(), from.Port())
-		r(from, buffer[:n])
+		// listenOutSingle uses ReadFromUDPAddrPort which discards cmsgs,
+		// so the outer ECN field is not visible on this path. Zero RxMeta
+		// (Not-ECT) means RFC 6040 combine is a no-op.
+		r(from, buffer[:n], RxMeta{})
+		flush()
 	}
 }
 
-func (u *StdConn) listenOutBatch(r EncReader) error {
+// readSockaddr decodes the source address out of a recvmmsg name buffer
+func (u *StdConn) readSockaddr(name []byte) netip.AddrPort {
 	var ip netip.Addr
+	// It's ok to skip the ok check here, the slicing is the only error that can occur and it will panic
+	if u.isV4 {
+		ip, _ = netip.AddrFromSlice(name[4:8])
+	} else {
+		ip, _ = netip.AddrFromSlice(name[8:24])
+	}
+	return netip.AddrPortFrom(ip.Unmap(), binary.BigEndian.Uint16(name[2:4]))
+}
+
+func (u *StdConn) listenOutBatch(r EncReader, flush func()) error {
 	var n int
 	var operr error
 
-	msgs, buffers, names := u.PrepareRawMessages(u.batch)
+	bufSize := MTU
+	cmsgSpace := 0
+	msgs, buffers, names, _ := u.PrepareRawMessages(u.batch, bufSize, cmsgSpace)
 
 	//reader needs to capture variables from this function, since it's used as a lambda with rawConn.Read
 	//defining it outside the loop so it gets re-used
@@ -211,22 +258,18 @@ func (u *StdConn) listenOutBatch(r EncReader) error {
 		}
 
 		for i := 0; i < n; i++ {
-			// Its ok to skip the ok check here, the slicing is the only error that can occur and it will panic
-			if u.isV4 {
-				ip, _ = netip.AddrFromSlice(names[i][4:8])
-			} else {
-				ip, _ = netip.AddrFromSlice(names[i][8:24])
-			}
-			r(netip.AddrPortFrom(ip.Unmap(), binary.BigEndian.Uint16(names[i][2:4])), buffers[i][:msgs[i].Len])
+			r(u.readSockaddr(names[i]), buffers[i][:msgs[i].Len], RxMeta{})
 		}
+
+		flush()
 	}
 }
 
-func (u *StdConn) ListenOut(r EncReader) error {
+func (u *StdConn) ListenOut(r EncReader, flush func()) error {
 	if u.batch == 1 {
-		return u.listenOutSingle(r)
+		return u.listenOutSingle(r, flush)
 	} else {
-		return u.listenOutBatch(r)
+		return u.listenOutBatch(r, flush)
 	}
 }
 
@@ -235,6 +278,120 @@ func (u *StdConn) WriteTo(b []byte, ip netip.AddrPort) error {
 	return err
 }
 
+// WriteBatch sends bufs via sendmmsg(2) using the preallocated scratch on
+// StdConn. If supported, consecutive packets to the same destination with
+// matching segment sizes (all but possibly the last) are coalesced into a
+// single mmsghdr entry
+//
+// If sendmmsg returns an error and zero entries went out, we fall back to
+// per-packet WriteTo for that chunk so the caller still gets best-effort
+// delivery. On a partial send we resume at the first un-acked entry on
+// the next iteration.
+func (u *StdConn) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, _ []byte) error {
+	for i := 0; i < len(bufs); {
+		chunk := min(len(bufs)-i, len(u.writeMsgs))
+
+		for k := 0; k < chunk; k++ {
+			u.writeIovs[k].Base = &bufs[i+k][0]
+			setIovLen(&u.writeIovs[k], len(bufs[i+k]))
+
+			nlen, err := writeSockaddr(u.writeNames[k], addrs[i+k], u.isV4)
+			if err != nil {
+				return err
+			}
+
+			hdr := &u.writeMsgs[k].Hdr
+			hdr.Iov = &u.writeIovs[k]
+			setMsgIovlen(hdr, 1)
+			hdr.Namelen = uint32(nlen)
+		}
+
+		sent, serr := u.sendmmsg(chunk)
+		if serr != nil && sent <= 0 {
+			// sendmmsg returns -1 / sent=0 when entry 0 itself failed; log
+			// that entry's destination and fall back to per-packet WriteTo
+			// for the whole chunk so the caller still gets best-effort
+			// delivery without duplicating packets the kernel accepted.
+			u.l.Warn("sendmmsg failed, falling back to per-packet WriteTo",
+				"err", serr,
+				"entries", chunk,
+				"entry0_dst", addrs[i],
+				"isV4", u.isV4,
+			)
+			for k := 0; k < chunk; k++ {
+				if werr := u.WriteTo(bufs[i+k], addrs[i+k]); werr != nil {
+					return werr
+				}
+			}
+			i += chunk
+			continue
+		}
+		i += sent
+	}
+	return nil
+}
+
+// sendmmsg issues sendmmsg(2) against the first n entries of u.writeMsgs.
+// The bound u.sendmmsgCB is passed to rawConn.Write so no closure is
+// allocated per call; inputs and outputs ride on the StdConn fields.
+func (u *StdConn) sendmmsg(n int) (int, error) {
+	u.sendmmsgN = n
+	u.sendmmsgSent = 0
+	u.sendmmsgErrno = 0
+	if err := u.rawConn.Write(u.sendmmsgCB); err != nil {
+		return u.sendmmsgSent, err
+	}
+	if u.sendmmsgErrno != 0 {
+		return u.sendmmsgSent, &net.OpError{Op: "sendmmsg", Err: u.sendmmsgErrno}
+	}
+	return u.sendmmsgSent, nil
+}
+
+// sendmmsgRun is the rawConn.Write callback. It is bound once into
+// u.sendmmsgCB at construction so it stays alloc-free in the hot path;
+// inputs (sendmmsgN) and outputs (sendmmsgSent, sendmmsgErrno) ride on
+// the receiver rather than escaping locals.
+func (u *StdConn) sendmmsgRun(fd uintptr) bool {
+	r1, _, errno := unix.Syscall6(unix.SYS_SENDMMSG, fd,
+		uintptr(unsafe.Pointer(&u.writeMsgs[0])), uintptr(u.sendmmsgN),
+		0, 0, 0,
+	)
+	if errno == syscall.EAGAIN || errno == syscall.EWOULDBLOCK {
+		return false
+	}
+	u.sendmmsgSent = int(r1)
+	u.sendmmsgErrno = errno
+	return true
+}
+
+// writeSockaddr encodes addr into buf (which must be at least
+// SizeofSockaddrInet6 bytes). Returns the number of bytes used. If isV4 is
+// true and addr is not a v4 (or v4-in-v6) address, returns an error.
+func writeSockaddr(buf []byte, addr netip.AddrPort, isV4 bool) (int, error) {
+	ap := addr.Addr().Unmap()
+	if isV4 {
+		if !ap.Is4() {
+			return 0, ErrInvalidIPv6RemoteForSocket
+		}
+		// struct sockaddr_in: { sa_family_t(2), in_port_t(2, BE), in_addr(4), zero(8) }
+		// sa_family is host endian.
+		binary.NativeEndian.PutUint16(buf[0:2], unix.AF_INET)
+		binary.BigEndian.PutUint16(buf[2:4], addr.Port())
+		ip4 := ap.As4()
+		copy(buf[4:8], ip4[:])
+		clear(buf[8:16])
+		return unix.SizeofSockaddrInet4, nil
+	}
+	// struct sockaddr_in6: { sa_family_t(2), in_port_t(2, BE), flowinfo(4), in6_addr(16), scope_id(4) }
+	binary.NativeEndian.PutUint16(buf[0:2], unix.AF_INET6)
+	binary.BigEndian.PutUint16(buf[2:4], addr.Port())
+	binary.NativeEndian.PutUint32(buf[4:8], 0)
+	ip6 := addr.Addr().As16()
+	copy(buf[8:24], ip6[:])
+	binary.NativeEndian.PutUint32(buf[24:28], 0)
+	return unix.SizeofSockaddrInet6, nil
+}
+
 func (u *StdConn) ReloadConfig(c *config.C) {
 	b := c.GetInt("listen.read_buffer", 0)
 	if b > 0 {

udp/udp_linux_32.go

@@ -30,13 +30,18 @@ type rawMessage struct {
 	Len uint32
 }
 
-func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
+func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [][]byte, [][]byte, []byte) {
 	msgs := make([]rawMessage, n)
 	buffers := make([][]byte, n)
 	names := make([][]byte, n)
 
+	var cmsgs []byte
+	if cmsgSpace > 0 {
+		cmsgs = make([]byte, n*cmsgSpace)
+	}
+
 	for i := range msgs {
-		buffers[i] = make([]byte, MTU)
+		buffers[i] = make([]byte, bufSize)
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
 		vs := []iovec{
@@ -48,7 +53,28 @@ func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
 
 		msgs[i].Hdr.Name = &names[i][0]
 		msgs[i].Hdr.Namelen = uint32(len(names[i]))
+
+		if cmsgSpace > 0 {
+			msgs[i].Hdr.Control = &cmsgs[i*cmsgSpace]
+			msgs[i].Hdr.Controllen = uint32(cmsgSpace)
+		}
 	}
 
-	return msgs, buffers, names
+	return msgs, buffers, names, cmsgs
+}
+
+func setIovLen(v *iovec, n int) {
+	v.Len = uint32(n)
+}
+
+func setMsgIovlen(m *msghdr, n int) {
+	m.Iovlen = uint32(n)
+}
+
+func setMsgControllen(m *msghdr, n int) {
+	m.Controllen = uint32(n)
+}
+
+func setCmsgLen(h *unix.Cmsghdr, n int) {
+	h.Len = uint32(n)
 }

udp/udp_linux_64.go

@@ -33,13 +33,18 @@ type rawMessage struct {
 	Pad0 [4]byte
 }
 
-func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
+func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [][]byte, [][]byte, []byte) {
 	msgs := make([]rawMessage, n)
 	buffers := make([][]byte, n)
 	names := make([][]byte, n)
 
+	var cmsgs []byte
+	if cmsgSpace > 0 {
+		cmsgs = make([]byte, n*cmsgSpace)
+	}
+
 	for i := range msgs {
-		buffers[i] = make([]byte, MTU)
+		buffers[i] = make([]byte, bufSize)
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
 		vs := []iovec{
@@ -51,7 +56,28 @@ func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]byte, [][]byte) {
 
 		msgs[i].Hdr.Name = &names[i][0]
 		msgs[i].Hdr.Namelen = uint32(len(names[i]))
+
+		if cmsgSpace > 0 {
+			msgs[i].Hdr.Control = &cmsgs[i*cmsgSpace]
+			msgs[i].Hdr.Controllen = uint64(cmsgSpace)
+		}
 	}
 
-	return msgs, buffers, names
+	return msgs, buffers, names, cmsgs
+}
+
+func setIovLen(v *iovec, n int) {
+	v.Len = uint64(n)
+}
+
+func setMsgIovlen(m *msghdr, n int) {
+	m.Iovlen = uint64(n)
+}
+
+func setMsgControllen(m *msghdr, n int) {
+	m.Controllen = uint64(n)
+}
+
+func setCmsgLen(h *unix.Cmsghdr, n int) {
+	h.Len = uint64(n)
 }

udp/udp_rio_windows.go

@@ -140,7 +140,7 @@ func (u *RIOConn) bind(l *slog.Logger, sa windows.Sockaddr) error {
 	return nil
 }
 
-func (u *RIOConn) ListenOut(r EncReader) error {
+func (u *RIOConn) ListenOut(r EncReader, flush func()) error {
 	buffer := make([]byte, MTU)
 
 	var lastRecvErr time.Time
@@ -161,7 +161,8 @@ func (u *RIOConn) ListenOut(r EncReader) error {
 			continue
 		}
 
-		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n])
+		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n], RxMeta{})
+		flush()
 	}
 }
 
@@ -316,6 +317,15 @@ func (u *RIOConn) WriteTo(buf []byte, ip netip.AddrPort) error {
 	return winrio.SendEx(u.rq, dataBuffer, 1, nil, addressBuffer, nil, nil, 0, 0)
 }
 
+func (u *RIOConn) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, _ []byte) error {
+	for i, b := range bufs {
+		if err := u.WriteTo(b, addrs[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (u *RIOConn) LocalAddr() (netip.AddrPort, error) {
 	sa, err := windows.Getsockname(u.sock)
 	if err != nil {

udp/udp_tester.go

@@ -157,15 +157,24 @@ func (u *TesterConn) WriteTo(b []byte, addr netip.AddrPort) error {
 		return nil
 	}
 }
+func (u *TesterConn) WriteBatch(bufs [][]byte, addrs []netip.AddrPort, _ []byte) error {
+	for i, b := range bufs {
+		if err := u.WriteTo(b, addrs[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}
 
-func (u *TesterConn) ListenOut(r EncReader) error {
+func (u *TesterConn) ListenOut(r EncReader, flush func()) error {
 	for {
 		select {
 		case <-u.done:
 			return os.ErrClosed
 		case p := <-u.RxPackets:
-			r(p.From, p.Data)
+			r(p.From, p.Data, RxMeta{})
 			p.Release()
+			flush()
 		}
 	}
 }

wire/wire.go

@@ -0,0 +1,17 @@
+package wire
+
+// TunPacket is the unit a read from a tun device returns.
+// On supported platforms, it may be a superpacket, but a single TunPacket will never have more than one destination.
+type TunPacket struct {
+	// Bytes contains the actual packet
+	Bytes []byte
+	// Meta contains other information to help process the packet correctly, such as offsets for segmentation offloads
+	// Fields in Meta should be as portable/platform-agnostic as possible.
+	Meta struct{}
+}
+
+// PerSegment invokes fn once per segment of pkt.
+// This is a stub implementation that does not actually support segmentation
+func (t *TunPacket) PerSegment(fn func(seg []byte) error) error {
+	return fn(t.Bytes)
+}