Experimenting

.github/actions/code-sign/action.yml

@@ -1,113 +0,0 @@
-name: Code-sign Windows binaries
-description: >
-  Sign every .exe under a given path in place via the DefinedNet code-signer
-  Lambda. If `role` or `bucket` is empty, logs a notice and skips signing so
-  forks and dev branches without AWS access still produce usable builds.
-
-inputs:
-  path:
-    description: "Directory whose .exe files should be signed in place"
-    required: true
-  role:
-    description: "IAM role ARN to assume via OIDC; empty disables signing"
-    required: false
-    default: ""
-  bucket:
-    description: "S3 staging bucket the code-signer Lambda reads from; empty disables signing"
-    required: false
-    default: ""
-  region:
-    description: "AWS region for the role and Lambda"
-    required: false
-    default: "us-east-2"
-  function-name:
-    description: "Code-signer Lambda function name"
-    required: false
-    default: "code-signer"
-  key-prefix:
-    description: "S3 key prefix the caller is authorized to write under"
-    required: false
-    default: "code-signing/slackhq/nebula"
-
-runs:
-  using: composite
-  steps:
-    - name: Skip notice
-      if: inputs.role == '' || inputs.bucket == ''
-      shell: sh
-      run: echo "::notice::code-signer role or bucket not set; skipping code signing."
-
-    - name: Configure AWS credentials
-      if: inputs.role != '' && inputs.bucket != ''
-      uses: aws-actions/configure-aws-credentials@v6
-      with:
-        role-to-assume: ${{ inputs.role }}
-        aws-region: ${{ inputs.region }}
-        # Default is 12 retries to ride out IAM trust-policy propagation; once
-        # the role is stable we want a real misconfiguration to fail fast.
-        retry-max-attempts: 5
-
-    - name: Sign .exe files
-      if: inputs.role != '' && inputs.bucket != ''
-      shell: sh
-      env:
-        SIGN_PATH: ${{ inputs.path }}
-        BUCKET: ${{ inputs.bucket }}
-        FUNCTION_NAME: ${{ inputs.function-name }}
-        KEY_PREFIX: ${{ inputs.key-prefix }}
-      run: |
-        set -eu
-        RUN="${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT}"
-
-        find "$SIGN_PATH" -name '*.exe' -print | while read -r path
-        do
-            rel=${path#"$SIGN_PATH"/}
-            file=$(basename "$path")
-            name=${file%.exe}
-            prefix="${KEY_PREFIX}/${RUN}"
-            src="${prefix}/unsigned/${rel}"
-            dst="${prefix}/signed/${rel}"
-
-            echo "::group::Sign ${rel}"
-            echo "Uploading unsigned to s3://${BUCKET}/${src}"
-            aws s3 cp --no-progress "$path" "s3://${BUCKET}/${src}" >/dev/null
-
-            echo "Invoking ${FUNCTION_NAME} Lambda"
-            payload=$(jq -nc \
-                --arg s "$src" \
-                --arg d "$dst" \
-                --arg p "$name" \
-                '{source_key: $s, dest_key: $d, program_name: $p}')
-            meta=$(aws lambda invoke \
-                --function-name "$FUNCTION_NAME" \
-                --cli-binary-format raw-in-base64-out \
-                --payload "$payload" \
-                --output json \
-                /tmp/sign-resp.json)
-            if echo "$meta" | jq -e '.FunctionError != null' >/dev/null
-            then
-                echo "::endgroup::"
-                echo "::error::code-signer Lambda failed for ${rel}"
-                cat /tmp/sign-resp.json >&2
-                exit 1
-            fi
-
-            echo "Downloading signed back to ${path}"
-            aws s3 cp --no-progress "s3://${BUCKET}/${dst}" "$path" >/dev/null
-
-            aws s3 rm "s3://${BUCKET}/${src}" >/dev/null 2>&1 || true
-            aws s3 rm "s3://${BUCKET}/${dst}" >/dev/null 2>&1 || true
-
-            # Sanity-check the bytes we got back actually carry an Authenticode
-            # signature that this machine can validate end to end.
-            status=$(powershell -NoProfile -Command "(Get-AuthenticodeSignature -FilePath '$path').Status" | tr -d '\r')
-            if [ "$status" != "Valid" ]
-            then
-                echo "::endgroup::"
-                echo "::error::${rel} signature status: ${status} (expected Valid)"
-                exit 1
-            fi
-
-            echo "Signed ${rel} (sha256=$(jq -r '.sha256' /tmp/sign-resp.json), status=${status})"
-            echo "::endgroup::"
-        done

.github/workflows/release.yml

@@ -24,7 +24,7 @@ jobs:
           mv build/*.tar.gz release
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v6
         with:
           name: linux-latest
           path: release
@@ -32,9 +32,6 @@ jobs:
   build-windows:
     name: Build Windows
     runs-on: windows-latest
-    permissions:
-      id-token: write
-      contents: read
     steps:
       - uses: actions/checkout@v6
 
@@ -57,15 +54,8 @@ jobs:
           mkdir build\dist\windows
           mv dist\windows\wintun build\dist\windows\
 
-      - name: Code-sign
-        uses: ./.github/actions/code-sign
-        with:
-          path: build
-          role: ${{ secrets.DEFINED_CODE_SIGNER_ROLE }}
-          bucket: ${{ secrets.DEFINED_CODE_SIGNER_BUCKET }}
-
       - name: Upload artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v6
         with:
           name: windows-latest
           path: build
@@ -85,7 +75,7 @@ jobs:
 
       - name: Import certificates
         if: env.HAS_SIGNING_CREDS == 'true'
-        uses: Apple-Actions/import-codesign-certs@v7
+        uses: Apple-Actions/import-codesign-certs@v6
         with:
           p12-file-base64: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_P12_BASE64 }}
           p12-password: ${{ secrets.APPLE_DEVELOPER_CERTIFICATE_PASSWORD }}
@@ -114,7 +104,7 @@ jobs:
           fi
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v6
         with:
           name: darwin-latest
           path: ./release/*
@@ -138,21 +128,21 @@ jobs:
 
       - name: Download artifacts
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@v7
         with:
           name: linux-latest
           path: artifacts
 
       - name: Login to Docker Hub
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: docker/login-action@v4
+        uses: docker/login-action@v3
         with:
           username: ${{ vars.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: Set up Docker Buildx
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
-        uses: docker/setup-buildx-action@v4
+        uses: docker/setup-buildx-action@v3
 
       - name: Build and push images
         if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
@@ -173,7 +163,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: Download artifacts
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@v7
         with:
           path: artifacts
 

.github/workflows/smoke-extra.yml

@@ -14,18 +14,10 @@ on:
       - 'go.sum'
 jobs:
 
-  smoke-extra-libvirt:
+  smoke-extra:
     if: github.ref == 'refs/heads/master' || contains(github.event.pull_request.labels.*.name, 'smoke-test-extra')
-    name: ${{ matrix.target }}
+    name: Run extra smoke tests
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        target:
-          - freebsd-amd64
-          - openbsd-amd64
-          - netbsd-amd64
-          - linux-amd64-ipv6disable
     env:
       VAGRANT_DEFAULT_PROVIDER: libvirt
     steps:
@@ -48,85 +40,28 @@ jobs:
         sudo chmod 666 /var/run/libvirt/libvirt-sock
         vagrant plugin install vagrant-libvirt
 
-    - name: ${{ matrix.target }}
-      run: make smoke-vagrant/${{ matrix.target }}
+    - name: freebsd-amd64
+      run: make smoke-vagrant/freebsd-amd64
 
-    timeout-minutes: 30
+    - name: openbsd-amd64
+      run: make smoke-vagrant/openbsd-amd64
 
-  # linux-386 needs VirtualBox, which conflicts with KVM/libvirt -- isolated job.
-  smoke-extra-virtualbox:
-    if: github.ref == 'refs/heads/master' || contains(github.event.pull_request.labels.*.name, 'smoke-test-extra')
-    name: linux-386
-    runs-on: ubuntu-latest
-    env:
-      VAGRANT_DEFAULT_PROVIDER: virtualbox
-    steps:
+    - name: netbsd-amd64
+      run: make smoke-vagrant/netbsd-amd64
 
-    - uses: actions/checkout@v6
+    - name: linux-amd64-ipv6disable
+      run: make smoke-vagrant/linux-amd64-ipv6disable
 
-    - uses: actions/setup-go@v6
-      with:
-        go-version: '1.25'
-        check-latest: true
-
-    - name: add hashicorp source
-      run: wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor | sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg && echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
-
-    - name: install vagrant and virtualbox
+    # linux-386 runs last because it requires disabling KVM to use VirtualBox,
+    # which prevents libvirt (used by the other tests) from working after this point.
+    - name: install virtualbox for i386 test
       run: |
-        sudo apt-get update && sudo apt-get install -y vagrant virtualbox
+        sudo apt-get install -y virtualbox
         sudo rmmod kvm_amd kvm_intel kvm 2>/dev/null || true
 
     - name: linux-386
+      env:
+        VAGRANT_DEFAULT_PROVIDER: virtualbox
       run: make smoke-vagrant/linux-386
 
     timeout-minutes: 30
-
-  smoke-windows:
-    if: github.ref == 'refs/heads/master' || contains(github.event.pull_request.labels.*.name, 'smoke-test-extra')
-    name: Run windows smoke test
-    runs-on: windows-latest
-    steps:
-
-    - uses: actions/checkout@v6
-
-    - uses: actions/setup-go@v6
-      with:
-        go-version: '1.25'
-        check-latest: true
-
-    # 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@v3
-      with:
-        distribution: Ubuntu-24.04
-        additional-packages: iputils-ping iproute2
-
-    # Vampire/setup-wsl provisions WSL1 even when the WSL2 platform is present.
-    # Convert the distro to WSL2 explicitly before we try to use /dev/net/tun.
-    - name: convert distro to WSL2
-      shell: pwsh
-      run: |
-        wsl --set-version Ubuntu-24.04 2
-        wsl --shutdown
-        wsl --list --verbose
-
-    - name: build windows nebula
-      run: make bin-windows
-
-    - name: build linux nebula for WSL
-      shell: bash
-      env:
-        GOOS: linux
-        GOARCH: amd64
-      run: |
-        mkdir -p build/linux-amd64
-        go build -o build/linux-amd64/nebula ./cmd/nebula
-
-    - name: run smoke-windows
-      shell: pwsh
-      working-directory: ./.github/workflows/smoke
-      run: ./smoke-windows.ps1
-
-    timeout-minutes: 15

.github/workflows/smoke/smoke-windows.ps1

@@ -1,272 +0,0 @@
-#!/usr/bin/env pwsh
-# Windows smoke test for the nebula tun + UDP + NLM code paths.
-#
-# Topology:
-#   - lighthouse runs natively on the Windows host (wintun + windows UDP)
-#   - peer runs inside WSL2 (Linux build of nebula, /dev/net/tun)
-#
-# WSL2 gives us a real netns boundary so the loopback fast-path on Windows
-# does not short-circuit the overlay -- when WSL pings the lighthouse VPN IP,
-# Linux has no idea that IP is local to the Windows host, so the packet is
-# forced through nebula. Same in reverse.
-
-$ErrorActionPreference = 'Stop'
-
-# wsl.exe emits UTF-16 LE by default which PowerShell reads as bytes, mangling
-# every captured string. WSL_UTF8 makes wsl.exe emit UTF-8 instead.
-$env:WSL_UTF8 = '1'
-
-$RepoRoot = Resolve-Path "$PSScriptRoot\..\..\.."
-$Nebula = Join-Path $RepoRoot 'nebula.exe'
-$NebulaCert = Join-Path $RepoRoot 'nebula-cert.exe'
-$NebulaLinux = Join-Path $RepoRoot 'build\linux-amd64\nebula'
-
-if (-not (Test-Path $Nebula)) { throw "missing $Nebula; run 'make bin-windows' first" }
-if (-not (Test-Path $NebulaCert)) { throw "missing $NebulaCert; run 'make bin-windows' first" }
-if (-not (Test-Path $NebulaLinux)) { throw "missing $NebulaLinux; build the linux nebula first" }
-
-# Matches the distro installed by Vampire/setup-wsl in smoke-extra.yml.
-$Distro = 'Ubuntu-24.04'
-$listed = (wsl --list --quiet 2>$null) -join "`n"
-if ($listed -notmatch [regex]::Escape($Distro)) {
-    throw "WSL distro $Distro not registered. Got: $listed"
-}
-Write-Host "Using WSL distro: $Distro"
-
-# Windows host as seen from inside WSL: WSL's default-route gateway. We extract
-# it with a regex rather than awk fields so PowerShell does not eat any '$N'
-# tokens, and tabs/double-spaces in `ip route` output do not confuse a cut.
-$ipCmd = 'ip route show default | grep -oE "([0-9]+\.){3}[0-9]+" | head -1'
-$WindowsIp = (wsl -d $Distro -- bash -c $ipCmd).Trim()
-if (-not $WindowsIp) { throw "could not determine Windows host IP from WSL" }
-Write-Host "Windows host IP from WSL: $WindowsIp"
-
-$WorkDir = Join-Path $env:TEMP 'nebula-smoke-windows'
-if (Test-Path $WorkDir) { Remove-Item -Recurse -Force $WorkDir }
-New-Item -ItemType Directory -Path $WorkDir | Out-Null
-
-$WslDir = '/tmp/nebula-smoke'
-wsl -d $Distro -- bash -c "rm -rf $WslDir && mkdir -p $WslDir" | Out-Null
-
-$DevName = 'nebula-smoke'
-$Ip1 = '192.168.241.1'
-$Ip2 = '192.168.241.2'
-$Port = 4242
-
-& $NebulaCert ca -name 'smoke-ca' -out-crt "$WorkDir\ca.crt" -out-key "$WorkDir\ca.key"
-if ($LASTEXITCODE -ne 0) { throw "nebula-cert ca failed (exit $LASTEXITCODE)" }
-
-& $NebulaCert sign -name 'lighthouse' -networks "$Ip1/24" -ca-crt "$WorkDir\ca.crt" -ca-key "$WorkDir\ca.key" -out-crt "$WorkDir\lighthouse.crt" -out-key "$WorkDir\lighthouse.key"
-if ($LASTEXITCODE -ne 0) { throw "nebula-cert sign lighthouse failed (exit $LASTEXITCODE)" }
-
-& $NebulaCert sign -name 'peer' -networks "$Ip2/24" -ca-crt "$WorkDir\ca.crt" -ca-key "$WorkDir\ca.key" -out-crt "$WorkDir\peer.crt" -out-key "$WorkDir\peer.key"
-if ($LASTEXITCODE -ne 0) { throw "nebula-cert sign peer failed (exit $LASTEXITCODE)" }
-
-# Windows lighthouse config.
-@"
-pki:
-  ca: $WorkDir\ca.crt
-  cert: $WorkDir\lighthouse.crt
-  key: $WorkDir\lighthouse.key
-static_host_map: {}
-lighthouse:
-  am_lighthouse: true
-  interval: 60
-  hosts: []
-listen:
-  host: 0.0.0.0
-  port: $Port
-tun:
-  disabled: false
-  dev: $DevName
-  drop_local_broadcast: false
-  drop_multicast: false
-  tx_queue: 500
-  mtu: 1300
-  network_category: private
-logging:
-  level: info
-  format: text
-firewall:
-  outbound_action: drop
-  inbound_action: drop
-  conntrack:
-    tcp_timeout: 12m
-    udp_timeout: 3m
-    default_timeout: 10m
-  outbound:
-    - port: any
-      proto: any
-      host: any
-  inbound:
-    - port: any
-      proto: any
-      host: any
-"@ | Out-File -FilePath "$WorkDir\lighthouse.yml" -Encoding utf8
-
-# WSL peer config (paths are POSIX, deliberately).
-@"
-pki:
-  ca: $WslDir/ca.crt
-  cert: $WslDir/peer.crt
-  key: $WslDir/peer.key
-static_host_map:
-  "${Ip1}": ["${WindowsIp}:$Port"]
-lighthouse:
-  am_lighthouse: false
-  interval: 60
-  hosts:
-    - "${Ip1}"
-listen:
-  host: 0.0.0.0
-  port: 0
-tun:
-  disabled: false
-  dev: nebula1
-  drop_local_broadcast: false
-  drop_multicast: false
-  tx_queue: 500
-  mtu: 1300
-logging:
-  level: info
-  format: text
-firewall:
-  outbound_action: drop
-  inbound_action: drop
-  conntrack:
-    tcp_timeout: 12m
-    udp_timeout: 3m
-    default_timeout: 10m
-  outbound:
-    - port: any
-      proto: any
-      host: any
-  inbound:
-    - port: any
-      proto: any
-      host: any
-"@ | Out-File -FilePath "$WorkDir\peer.yml" -Encoding utf8
-
-# Stage WSL artifacts. Convert Windows paths to WSL paths ourselves rather than
-# calling `wslpath`, because PowerShell's argument-passing to external EXEs
-# strips backslashes from path arguments in ways that are hard to escape around.
-function ConvertTo-WslPath {
-    param([string]$WindowsPath)
-    if ($WindowsPath -notmatch '^([A-Za-z]):\\(.*)$') {
-        throw "cannot convert path to WSL: $WindowsPath"
-    }
-    return "/mnt/$($matches[1].ToLower())/$($matches[2].Replace('\','/'))"
-}
-
-$WslWorkDir = ConvertTo-WslPath $WorkDir
-$WslNebulaPath = ConvertTo-WslPath $NebulaLinux
-wsl -d $Distro -- bash -c "cp '$WslWorkDir/ca.crt' '$WslWorkDir/peer.crt' '$WslWorkDir/peer.key' '$WslWorkDir/peer.yml' $WslDir/ && cp '$WslNebulaPath' $WslDir/nebula && chmod +x $WslDir/nebula"
-
-# Make sure WSL has tun support and /dev/net/tun is usable before starting
-# nebula. Diagnostics first so a fail here points at the real problem (e.g.
-# WSL1 distros do not have a real kernel and will not have tun).
-Write-Host '=== WSL diagnostic ==='
-wsl --version 2>&1 | Out-Host
-wsl --list --verbose 2>&1 | Out-Host
-wsl -d $Distro -u root -- uname -a | Out-Host
-wsl -d $Distro -u root -- bash -c "modprobe tun 2>&1 || true; mkdir -p /dev/net; [ -c /dev/net/tun ] || mknod /dev/net/tun c 10 200; chmod 600 /dev/net/tun; ls -l /dev/net/tun"
-if ($LASTEXITCODE -ne 0) { throw "failed to prepare /dev/net/tun in WSL (TUN support missing?)" }
-
-# Deliberately no New-NetFirewallRule calls here -- nebula's windows_bypass_wdf
-# feature is supposed to install WFP permit filters that let inbound traffic
-# through Windows Defender Firewall on its own. If this smoke regresses, that
-# feature regressed.
-
-$lhOut = Join-Path $WorkDir 'lighthouse.out.log'
-$lhErr = Join-Path $WorkDir 'lighthouse.err.log'
-$lhProc = Start-Process -FilePath $Nebula -ArgumentList @('-config', "$WorkDir\lighthouse.yml") `
-    -PassThru -NoNewWindow `
-    -RedirectStandardOutput $lhOut `
-    -RedirectStandardError $lhErr
-
-# Run nebula in WSL as root with no sudo + no shell wrapper. PowerShell's
-# Start-Process arg quoting mangles `bash -c "..."` strings that contain
-# spaces/redirections, so we skip bash entirely and let Start-Process do the
-# stdout/stderr capture itself.
-$peerOut = Join-Path $WorkDir 'peer.out.log'
-$peerErr = Join-Path $WorkDir 'peer.err.log'
-$peerProc = Start-Process -FilePath 'wsl' `
-    -ArgumentList @('-d', $Distro, '-u', 'root', '--', "$WslDir/nebula", '-config', "$WslDir/peer.yml") `
-    -PassThru -NoNewWindow `
-    -RedirectStandardOutput $peerOut `
-    -RedirectStandardError $peerErr
-
-function Wait-Until {
-    param([scriptblock]$Predicate, [int]$TimeoutSec, [string]$What)
-    $deadline = (Get-Date).AddSeconds($TimeoutSec)
-    while ((Get-Date) -lt $deadline) {
-        if (& $Predicate) { return }
-        Start-Sleep -Milliseconds 500
-    }
-    throw "timed out waiting for: $What"
-}
-
-try {
-    Wait-Until -TimeoutSec 30 -What "windows wintun adapter $DevName with NetworkCategory=Private" -Predicate {
-        if ($lhProc.HasExited) { throw "lighthouse exited (code $($lhProc.ExitCode)) before tun was ready" }
-        $p = Get-NetConnectionProfile -InterfaceAlias $DevName -ErrorAction SilentlyContinue
-        $p -and ("$($p.NetworkCategory)" -ieq 'Private')
-    }
-    Write-Host "OK: $DevName NetworkCategory=Private"
-
-    Wait-Until -TimeoutSec 30 -What "WSL nebula1 with $Ip2" -Predicate {
-        if ($peerProc.HasExited) { throw "peer exited (code $($peerProc.ExitCode)) before tun was ready" }
-        $r = wsl -d $Distro -u root -- bash -c "ip -o addr show nebula1 2>/dev/null | grep -q 'inet $Ip2' && echo yes"
-        ("$r").Trim() -eq 'yes'
-    }
-    Write-Host "OK: WSL nebula1 has $Ip2"
-
-    Wait-Until -TimeoutSec 30 -What "ping from WSL peer to windows lighthouse ($Ip1)" -Predicate {
-        if ($peerProc.HasExited) { throw "peer exited (code $($peerProc.ExitCode)) before ping succeeded" }
-        $r = wsl -d $Distro -u root -- bash -c "ping -c1 -W1 $Ip1 >/dev/null 2>&1 && echo OK"
-        ("$r").Trim() -eq 'OK'
-    }
-    Write-Host "OK: WSL peer -> windows lighthouse"
-
-    Wait-Until -TimeoutSec 30 -What "ping from windows lighthouse to WSL peer ($Ip2)" -Predicate {
-        $null = & ping.exe -n 1 -w 1000 $Ip2
-        $LASTEXITCODE -eq 0
-    }
-    Write-Host "OK: windows lighthouse -> WSL peer"
-
-    Write-Host ''
-    Write-Host 'All smoke checks passed.'
-}
-catch {
-    Write-Host ''
-    Write-Host '=== lighthouse stdout ==='
-    Get-Content $lhOut -ErrorAction SilentlyContinue | Out-Host
-    Write-Host '=== lighthouse stderr ==='
-    Get-Content $lhErr -ErrorAction SilentlyContinue | Out-Host
-    Write-Host '=== peer stdout ==='
-    Get-Content $peerOut -ErrorAction SilentlyContinue | Out-Host
-    Write-Host '=== peer stderr ==='
-    Get-Content $peerErr -ErrorAction SilentlyContinue | Out-Host
-    Write-Host '=== nebula WFP filters ==='
-    # Dump nebula-installed filters so we can verify they got registered with
-    # the conditions we expect.
-    $wfpDump = Join-Path $WorkDir 'wfp.xml'
-    netsh wfp show filters file=$wfpDump 2>&1 | Out-Null
-    if (Test-Path $wfpDump) {
-        Select-String -Path $wfpDump -Pattern 'Nebula' -Context 0,80 -ErrorAction SilentlyContinue | Out-Host
-    }
-    throw
-}
-finally {
-    if (-not $lhProc.HasExited) {
-        Stop-Process -Id $lhProc.Id -Force -ErrorAction SilentlyContinue
-        $lhProc.WaitForExit(5000) | Out-Null
-    }
-    wsl -d $Distro -u root -- bash -c "pkill -f $WslDir/nebula 2>/dev/null; true" | Out-Null
-    # pkill returns 1 when no match and wsl propagates that; the smoke is done
-    # so we don't want it to leak into the script's exit code.
-    $global:LASTEXITCODE = 0
-    if ($peerProc -and -not $peerProc.HasExited) {
-        Stop-Process -Id $peerProc.Id -Force -ErrorAction SilentlyContinue
-    }
-}

.github/workflows/smoke/vagrant-netbsd-amd64/Vagrantfile

@@ -1,7 +1,7 @@
 # -*- mode: ruby -*-
 # vi: set ft=ruby :
 Vagrant.configure("2") do |config|
-  config.vm.box = "DefinedNet/netbsd10"
+  config.vm.box = "generic/netbsd9"
 
   config.vm.synced_folder "../build", "/nebula", type: "rsync"
 end

.github/workflows/test.yml

@@ -45,7 +45,7 @@ jobs:
     - name: Build test mobile
       run: make build-test-mobile
 
-    - uses: actions/upload-artifact@v7
+    - uses: actions/upload-artifact@v6
       with:
         name: e2e packet flow linux-latest
         path: e2e/mermaid/linux-latest
@@ -125,7 +125,7 @@ jobs:
     - name: End 2 end
       run: make e2evv
 
-    - uses: actions/upload-artifact@v7
+    - uses: actions/upload-artifact@v6
       with:
         name: e2e packet flow ${{ matrix.os }}
         path: e2e/mermaid/${{ matrix.os }}

bits.go

@@ -2,42 +2,24 @@ package nebula
 
 import (
 	"context"
-	"fmt"
 	"log/slog"
-	"math"
-	mathbits "math/bits"
 
 	"github.com/rcrowley/go-metrics"
 )
 
-const bitsPerWord = 64
-
-// Bits is a sliding-window anti-replay tracker. The window is stored as a
-// circular bitmap packed into uint64 words (8x denser than a []bool), so a
-// length-N window costs N/8 bytes. length must be a power of two.
 type Bits struct {
 	length             uint64
-	lengthMask         uint64
 	current            uint64
-	bits               []uint64
+	bits               []bool
 	lostCounter        metrics.Counter
 	dupeCounter        metrics.Counter
 	outOfWindowCounter metrics.Counter
 }
 
-func NewBits(length uint64) *Bits {
-	if length == 0 || length&(length-1) != 0 {
-		panic(fmt.Sprintf("Bits length must be a power of two, got %d", length))
-	}
-
-	nWords := length / bitsPerWord
-	if nWords == 0 {
-		nWords = 1
-	}
+func NewBits(bits uint64) *Bits {
 	b := &Bits{
-		length:             length,
-		lengthMask:         length - 1,
-		bits:               make([]uint64, nWords),
+		length:             bits,
+		bits:               make([]bool, bits, bits),
 		current:            0,
 		lostCounter:        metrics.GetOrRegisterCounter("network.packets.lost", nil),
 		dupeCounter:        metrics.GetOrRegisterCounter("network.packets.duplicate", nil),
@@ -45,194 +27,71 @@ func NewBits(length uint64) *Bits {
 	}
 
 	// There is no counter value 0, mark it to avoid counting a lost packet later.
-	b.bits[0] = 1
+	b.bits[0] = true
+	b.current = 0
 	return b
 }
 
-func (b *Bits) get(i uint64) bool {
-	pos := i & b.lengthMask
-	//bit-shifting by 6 because i is a bit index, not a u64 index, and we need to find the u64 without bit in it
-	return b.bits[pos>>6]&(uint64(1)<<(pos&63)) != 0
-}
-
-func (b *Bits) set(i uint64) {
-	pos := i & b.lengthMask
-	b.bits[pos>>6] |= uint64(1) << (pos & 63)
-}
-
-// clearRange clears `count` bits starting at circular position `startPos`
-// (already masked to [0, length)) and returns how many of them were set
-// before the clear. count must be in [1, length].
-func (b *Bits) clearRange(startPos, count uint64) uint64 {
-	wasSet := uint64(0)
-	if count >= b.length {
-		for _, w := range b.bits {
-			wasSet += uint64(mathbits.OnesCount64(w))
-		}
-		clear(b.bits)
-		return wasSet
-	}
-
-	pos := startPos
-	remaining := count
-
-	// handle the potential partial word before pos becomes u64 aligned
-	word := pos >> 6
-	bit := pos & 63
-	take := uint64(64) - bit
-	if take > remaining {
-		take = remaining
-	}
-	if take > b.length-pos {
-		take = b.length - pos
-	}
-	var mask uint64
-	if take == 64 {
-		mask = math.MaxUint64
-	} else {
-		mask = ((uint64(1) << take) - 1) << bit
-	}
-	wasSet += uint64(mathbits.OnesCount64(b.bits[word] & mask))
-	b.bits[word] &^= mask
-	remaining -= take
-	pos = (pos + take) & b.lengthMask
-
-	// Clear whole words, keeping track of the number of set bits
-	for remaining >= 64 {
-		word = pos >> 6
-		wasSet += uint64(mathbits.OnesCount64(b.bits[word]))
-		b.bits[word] = 0
-		remaining -= 64
-		pos = (pos + 64) & b.lengthMask
-	}
-
-	// Clear the remaining partial word
-	if remaining > 0 {
-		word = pos >> 6
-		mask = (uint64(1) << remaining) - 1
-		wasSet += uint64(mathbits.OnesCount64(b.bits[word] & mask))
-		b.bits[word] &^= mask
-	}
-
-	return wasSet
-}
-
-func (b *Bits) strictlyWithinWindow(i uint64) bool {
-	// Handle the case where the window hasn't slid yet. This avoids u64 underflow.
-	inWarmup := b.current < b.length
-	if i < b.length && inWarmup {
-		return true
-	}
-
-	// Next, if the packet is in-window, see if we've seen it before
-	if i > b.current-b.length {
-		return true
-	}
-	return false //not within window!
-}
-
-// Check returns true if i is within (or way out in front of) the window, and not a replay
 func (b *Bits) Check(l *slog.Logger, i uint64) bool {
 	// If i is the next number, return true.
 	if i > b.current {
 		return true
 	}
 
-	if b.strictlyWithinWindow(i) {
-		return !b.get(i)
+	// If i is within the window, check if it's been set already.
+	if i > b.current-b.length || i < b.length && b.current < b.length {
+		return !b.bits[i%b.length]
 	}
 
 	// Not within the window
 	if l.Enabled(context.Background(), slog.LevelDebug) {
-		l.Debug("rejected a packet (top)", "current", b.current, "incoming", i)
+		l.Debug("rejected a packet (top)",
+			"current", b.current,
+			"incoming", i,
+		)
 	}
 	return false
 }
 
-// Update has three branches:
-//   - i == b.current+1: fast path; advance the cursor by one and lose-count
-//     the slot we just stomped (only past warmup; see the i > b.length guard
-//     below).
-//   - i  >  b.current+1: jump path; clear all slots between current and i
-//     (or up to a full window's worth, whichever is smaller) via clearRange,
-//     then mark i. Two arms here: a warmup arm that handles the very first
-//     window before the cursor has slid, and a steady-state arm that treats
-//     every cleared empty slot as a lost packet.
-//   - i  <= b.current: in-window check for duplicates; out-of-window otherwise.
-//
-// NewBits seeds bits[0]=1 so counter 0 looks "received" — Update never
-// clears that marker during warmup (clearRange skips position 0 when
-// startPos=1), and once b.current >= b.length the marker is no longer
-// consulted. The marker prevents a fictitious "lost" hit on the first real
-// counter.
 func (b *Bits) Update(l *slog.Logger, i uint64) bool {
-	// Fast path: i is the next expected counter. Split out so the function
-	// stays small and avoids paying for the slow paths' slog argument-build
-	// stack frame on every call. The bit read/test/write is inlined to
-	// touch the backing word once.
+	// If i is the next number, return true and update current.
 	if i == b.current+1 {
-		pos := i & b.lengthMask
-		word := pos >> 6
-		mask := uint64(1) << (pos & 63)
-		w := b.bits[word]
-		if i > b.length && w&mask == 0 {
+		// Check if the oldest bit was lost since we are shifting the window by 1 and occupying it with this counter
+		// The very first window can only be tracked as lost once we are on the 2nd window or greater
+		if b.bits[i%b.length] == false && i > b.length {
 			b.lostCounter.Inc(1)
 		}
-		b.bits[word] = w | mask
+		b.bits[i%b.length] = true
 		b.current = i
 		return true
 	}
-	return b.updateSlow(l, i)
-}
 
-// updateSlow handles jumps, in-window backfill, dupes, and out-of-window.
-func (b *Bits) updateSlow(l *slog.Logger, i uint64) bool {
 	// If i is a jump, adjust the window, record lost, update current, and return true
 	if i > b.current {
-		end := i
-		if end > b.current+b.length {
-			end = b.current + b.length
-		}
-		count := end - b.current
-		startPos := (b.current + 1) & b.lengthMask
-
-		var lost int64
-		if b.current >= b.length {
-			// Steady state: every cleared slot is past warmup, so any unset
-			// bit we evict is a lost packet from the previous cycle.
-			wasSet := b.clearRange(startPos, count)
-			lost = int64(count) - int64(wasSet)
-		} else {
-			// Warmup (the very first window). Some cleared slots represent
-			// packets <= length where eviction is not "lost" in the usual
-			// sense. This branch is taken at most once per connection so we
-			// don't bother optimizing it.
-			for n := b.current + 1; n <= end; n++ {
-				if !b.get(n) && n > b.length {
-					lost++
-				}
+		lost := int64(0)
+		// Zero out the bits between the current and the new counter value, limited by the window size,
+		// since the window is shifting
+		for n := b.current + 1; n <= min(i, b.current+b.length); n++ {
+			if b.bits[n%b.length] == false && n > b.length {
+				lost++
 			}
-			b.clearRange(startPos, count)
+			b.bits[n%b.length] = false
 		}
 
-		// Anything past the new window can never be backfilled, so it's lost.
-		if i > b.current+b.length {
-			lost += int64(i - b.current - b.length)
-		}
+		// Only record any skipped packets as a result of the window moving further than the window length
+		// Any loss within the new window will be accounted for in future calls
+		lost += max(0, int64(i-b.current-b.length))
 		b.lostCounter.Inc(lost)
 
-		b.set(i)
+		b.bits[i%b.length] = true
 		b.current = i
 		return true
 	}
 
-	// If i is within the current window but below the current counter, check to see if it's a duplicate
-	if b.strictlyWithinWindow(i) {
-		pos := i & b.lengthMask
-		word := pos >> 6
-		mask := uint64(1) << (pos & 63)
-		w := b.bits[word]
-		if b.current == i || w&mask != 0 {
+	// If i is within the current window but below the current counter,
+	// Check to see if it's a duplicate
+	if i > b.current-b.length || i < b.length && b.current < b.length {
+		if b.current == i || b.bits[i%b.length] == true {
 			if l.Enabled(context.Background(), slog.LevelDebug) {
 				l.Debug("Receive window",
 					"accepted", false,
@@ -245,7 +104,7 @@ func (b *Bits) updateSlow(l *slog.Logger, i uint64) bool {
 			return false
 		}
 
-		b.bits[word] = w | mask
+		b.bits[i%b.length] = true
 		return true
 	}
 

bits_test.go

@@ -7,79 +7,61 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-// snapshot returns the bitmap as a []bool of length b.length, for readable
-// test assertions against the now-packed []uint64 storage.
-func (b *Bits) snapshot() []bool {
-	out := make([]bool, b.length)
-	for i := uint64(0); i < b.length; i++ {
-		out[i] = b.get(i)
-	}
-	return out
-}
-
-func TestBitsRequiresPowerOfTwo(t *testing.T) {
-	assert.Panics(t, func() { NewBits(10) })
-	assert.Panics(t, func() { NewBits(0) })
-	assert.NotPanics(t, func() { NewBits(1) })
-	assert.NotPanics(t, func() { NewBits(16) })
-	assert.NotPanics(t, func() { NewBits(1024) })
-	assert.NotPanics(t, func() { NewBits(16384) })
-}
-
 func TestBits(t *testing.T) {
 	l := test.NewLogger()
-	b := NewBits(16)
-	assert.EqualValues(t, 16, b.length)
+	b := NewBits(10)
+
+	// make sure it is the right size
+	assert.Len(t, b.bits, 10)
 
 	// This is initialized to zero - receive one. This should work.
 	assert.True(t, b.Check(l, 1))
 	assert.True(t, b.Update(l, 1))
 	assert.EqualValues(t, 1, b.current)
-	g := []bool{true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false}
-	assert.Equal(t, g, b.snapshot())
+	g := []bool{true, true, false, false, false, false, false, false, false, false}
+	assert.Equal(t, g, b.bits)
 
 	// Receive two
 	assert.True(t, b.Check(l, 2))
 	assert.True(t, b.Update(l, 2))
 	assert.EqualValues(t, 2, b.current)
-	g = []bool{true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false}
-	assert.Equal(t, g, b.snapshot())
+	g = []bool{true, true, true, false, false, false, false, false, false, false}
+	assert.Equal(t, g, b.bits)
 
 	// Receive two again - it will fail
 	assert.False(t, b.Check(l, 2))
 	assert.False(t, b.Update(l, 2))
 	assert.EqualValues(t, 2, b.current)
 
-	// Jump ahead to 25, which clears the window and sets slot 25%16 = 9.
-	assert.True(t, b.Check(l, 25))
-	assert.True(t, b.Update(l, 25))
-	assert.EqualValues(t, 25, b.current)
-	g = []bool{false, false, false, false, false, false, false, false, false, true, false, false, false, false, false, false}
-	assert.Equal(t, g, b.snapshot())
+	// Jump ahead to 15, which should clear everything and set the 6th element
+	assert.True(t, b.Check(l, 15))
+	assert.True(t, b.Update(l, 15))
+	assert.EqualValues(t, 15, b.current)
+	g = []bool{false, false, false, false, false, true, false, false, false, false}
+	assert.Equal(t, g, b.bits)
 
-	// Mark 24, which is in window (current 25, length 16, window covers [10,25]).
-	assert.True(t, b.Check(l, 24))
-	assert.True(t, b.Update(l, 24))
-	assert.EqualValues(t, 25, b.current)
-	g = []bool{false, false, false, false, false, false, false, false, true, true, false, false, false, false, false, false}
-	assert.Equal(t, g, b.snapshot())
+	// Mark 14, which is allowed because it is in the window
+	assert.True(t, b.Check(l, 14))
+	assert.True(t, b.Update(l, 14))
+	assert.EqualValues(t, 15, b.current)
+	g = []bool{false, false, false, false, true, true, false, false, false, false}
+	assert.Equal(t, g, b.bits)
 
-	// Mark 5, not allowed because 5 <= current-length (25-16=9).
+	// Mark 5, which is not allowed because it is not in the window
 	assert.False(t, b.Check(l, 5))
 	assert.False(t, b.Update(l, 5))
-	assert.EqualValues(t, 25, b.current)
-	g = []bool{false, false, false, false, false, false, false, false, true, true, false, false, false, false, false, false}
-	assert.Equal(t, g, b.snapshot())
+	assert.EqualValues(t, 15, b.current)
+	g = []bool{false, false, false, false, true, true, false, false, false, false}
+	assert.Equal(t, g, b.bits)
 
-	// Make sure we handle wrapping around once to the same slot. With
-	// length=16, packets 1 and 17 share slot 1.
-	b = NewBits(16)
+	// make sure we handle wrapping around once to the current position
+	b = NewBits(10)
 	assert.True(t, b.Update(l, 1))
-	assert.True(t, b.Update(l, 17))
-	assert.Equal(t, []bool{false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false}, b.snapshot())
+	assert.True(t, b.Update(l, 11))
+	assert.Equal(t, []bool{false, true, false, false, false, false, false, false, false, false}, b.bits)
 
 	// Walk through a few windows in order
-	b = NewBits(16)
+	b = NewBits(10)
 	for i := uint64(1); i <= 100; i++ {
 		assert.True(t, b.Check(l, i), "Error while checking %v", i)
 		assert.True(t, b.Update(l, i), "Error while updating %v", i)
@@ -90,31 +72,24 @@ func TestBits(t *testing.T) {
 
 func TestBitsLargeJumps(t *testing.T) {
 	l := test.NewLogger()
-
-	// length=16. Update(55) from current=0:
-	//   warmup, per-bit loop sees no n>16 with unset bits (slot 0 was set by
-	//   NewBits and gets re-evaluated when n=16; n=16 is not strictly > 16),
-	//   so the loop contributes 0. The jump exceeds the window so we record
-	//   55 - 0 - 16 = 39 packets fell out the back.
-	b := NewBits(16)
+	b := NewBits(10)
 	b.lostCounter.Clear()
-	assert.True(t, b.Update(l, 55))
-	assert.Equal(t, int64(39), b.lostCounter.Count())
 
-	// Update(100): clears 16 slots starting at slot 56%16=8. Only slot 7 (for
-	// packet 55) was set, so 16 - 1 = 15 evicted slots had unset bits.
-	// Plus 100 - 55 - 16 = 29 packets fell past the window. Total 44.
-	assert.True(t, b.Update(l, 100))
-	assert.Equal(t, int64(39+44), b.lostCounter.Count())
+	b = NewBits(10)
+	b.lostCounter.Clear()
+	assert.True(t, b.Update(l, 55)) // We saw packet 55 and can still track 45,46,47,48,49,50,51,52,53,54
+	assert.Equal(t, int64(45), b.lostCounter.Count())
 
-	// Update(200): same shape: 16 - 1 = 15 evicted unset, plus 200 - 100 - 16 = 84 past window. Total 99.
-	assert.True(t, b.Update(l, 200))
-	assert.Equal(t, int64(39+44+99), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 100)) // We saw packet 55 and 100 and can still track 90,91,92,93,94,95,96,97,98,99
+	assert.Equal(t, int64(89), b.lostCounter.Count())
+
+	assert.True(t, b.Update(l, 200)) // We saw packet 55, 100, and 200 and can still track 190,191,192,193,194,195,196,197,198,199
+	assert.Equal(t, int64(188), b.lostCounter.Count())
 }
 
 func TestBitsDupeCounter(t *testing.T) {
 	l := test.NewLogger()
-	b := NewBits(16)
+	b := NewBits(10)
 	b.lostCounter.Clear()
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
@@ -139,117 +114,120 @@ func TestBitsDupeCounter(t *testing.T) {
 
 func TestBitsOutOfWindowCounter(t *testing.T) {
 	l := test.NewLogger()
-	b := NewBits(16)
+	b := NewBits(10)
 	b.lostCounter.Clear()
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	// Jump to 20 (warmup branch + 4 past-window packets).
 	assert.True(t, b.Update(l, 20))
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 
-	// 9 single-step advances, each evicts a slot whose bit was cleared during
-	// the jump above and whose value was never seen, so each contributes 1
-	// to lostCounter.
-	for n := uint64(21); n <= 29; n++ {
-		assert.True(t, b.Update(l, n))
-	}
+	assert.True(t, b.Update(l, 21))
+	assert.True(t, b.Update(l, 22))
+	assert.True(t, b.Update(l, 23))
+	assert.True(t, b.Update(l, 24))
+	assert.True(t, b.Update(l, 25))
+	assert.True(t, b.Update(l, 26))
+	assert.True(t, b.Update(l, 27))
+	assert.True(t, b.Update(l, 28))
+	assert.True(t, b.Update(l, 29))
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 
-	// 0 is below current-length (29-16=13) so it falls outside the window.
 	assert.False(t, b.Update(l, 0))
 	assert.Equal(t, int64(1), b.outOfWindowCounter.Count())
 
-	// 4 from the Update(20) jump + 9 from 21..29.
-	assert.Equal(t, int64(13), b.lostCounter.Count())
+	assert.Equal(t, int64(19), b.lostCounter.Count()) // packet 0 wasn't lost
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(1), b.outOfWindowCounter.Count())
 }
 
 func TestBitsLostCounter(t *testing.T) {
 	l := test.NewLogger()
-	b := NewBits(16)
+	b := NewBits(10)
 	b.lostCounter.Clear()
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	// Walk 20..29 like the original, just with a bigger window. Same
-	// reasoning as TestBitsOutOfWindowCounter: 4 past-window from Update(20),
-	// then 9 more from the unit advances.
-	for n := uint64(20); n <= 29; n++ {
-		assert.True(t, b.Update(l, n))
-	}
-	assert.Equal(t, int64(13), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 20))
+	assert.True(t, b.Update(l, 21))
+	assert.True(t, b.Update(l, 22))
+	assert.True(t, b.Update(l, 23))
+	assert.True(t, b.Update(l, 24))
+	assert.True(t, b.Update(l, 25))
+	assert.True(t, b.Update(l, 26))
+	assert.True(t, b.Update(l, 27))
+	assert.True(t, b.Update(l, 28))
+	assert.True(t, b.Update(l, 29))
+	assert.Equal(t, int64(19), b.lostCounter.Count()) // packet 0 wasn't lost
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 
-	b = NewBits(16)
+	b = NewBits(10)
 	b.lostCounter.Clear()
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	// Update(15) clears the warmup window (no lost), sets slot 15.
-	assert.True(t, b.Update(l, 15))
+	assert.True(t, b.Update(l, 9))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
-
-	// Update(16): slot 0 was already set (NewBits seeded it), and 16 is not
-	// strictly > length, so nothing is recorded as lost.
-	assert.True(t, b.Update(l, 16))
+	// 10 will set 0 index, 0 was already set, no lost packets
+	assert.True(t, b.Update(l, 10))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
-
-	// Update(17): we jumped straight from 0 to 15, so slot 1 was cleared
-	// (and never re-set). 17 > 16 is past warmup, so packet 1 is recorded lost.
-	assert.True(t, b.Update(l, 17))
+	// 11 will set 1 index, 1 was missed, we should see 1 packet lost
+	assert.True(t, b.Update(l, 11))
 	assert.Equal(t, int64(1), b.lostCounter.Count())
+	// Now let's fill in the window, should end up with 8 lost packets
+	assert.True(t, b.Update(l, 12))
+	assert.True(t, b.Update(l, 13))
+	assert.True(t, b.Update(l, 14))
+	assert.True(t, b.Update(l, 15))
+	assert.True(t, b.Update(l, 16))
+	assert.True(t, b.Update(l, 17))
+	assert.True(t, b.Update(l, 18))
+	assert.True(t, b.Update(l, 19))
+	assert.Equal(t, int64(8), b.lostCounter.Count())
 
-	// Fill in 18..30 in single steps. Each i evicts slot i%16. Slots 2..14
-	// were all cleared during Update(15), and we never re-set any of them,
-	// so each i in 18..30 is a fresh lost packet — 13 more.
-	for n := uint64(18); n <= 30; n++ {
-		assert.True(t, b.Update(l, n))
-	}
-	assert.Equal(t, int64(14), b.lostCounter.Count())
+	// Jump ahead by a window size
+	assert.True(t, b.Update(l, 29))
+	assert.Equal(t, int64(8), b.lostCounter.Count())
+	// Now lets walk ahead normally through the window, the missed packets should fill in
+	assert.True(t, b.Update(l, 30))
+	assert.True(t, b.Update(l, 31))
+	assert.True(t, b.Update(l, 32))
+	assert.True(t, b.Update(l, 33))
+	assert.True(t, b.Update(l, 34))
+	assert.True(t, b.Update(l, 35))
+	assert.True(t, b.Update(l, 36))
+	assert.True(t, b.Update(l, 37))
+	assert.True(t, b.Update(l, 38))
+	// 39 packets tracked, 22 seen, 17 lost
+	assert.Equal(t, int64(17), b.lostCounter.Count())
 
-	// Jump ahead by exactly one window size.
-	assert.True(t, b.Update(l, 46))
-	// end = min(46, 30+16) = 46, count = 16, all slots cleared. Before the
-	// jump every slot 0..15 had been set (Update(15), (16), (17), 18..30),
-	// so wasSet=16 and 46 == current+length means no past-window slack:
-	// lost contribution = 0.
-	assert.Equal(t, int64(14), b.lostCounter.Count())
-
-	// Walk 47..55. The Update(46) jump cleared every slot, so only slot 14
-	// (for packet 46) is set when we start. Each subsequent unit step lands
-	// on a slot that was cleared and is past warmup, so it counts as lost.
-	// 9 more = 23.
-	for n := uint64(47); n <= 55; n++ {
-		assert.True(t, b.Update(l, n))
-	}
-	assert.Equal(t, int64(23), b.lostCounter.Count())
-
-	// Jump ahead by two windows: clears the window plus past-window loss.
-	assert.True(t, b.Update(l, 87))
-	// current=55, length=16. end = min(87, 71) = 71. count=16, all slots
-	// cleared. Slots set before the clear are slots 14,15,0..7 (10 total).
-	// Lost from clear = 16 - 10 = 6. Past window: 87 - 55 - 16 = 16. +22.
-	assert.Equal(t, int64(45), b.lostCounter.Count())
+	// Jump ahead by 2 windows, should have recording 1 full window missing
+	assert.True(t, b.Update(l, 58))
+	assert.Equal(t, int64(27), b.lostCounter.Count())
+	// Now lets walk ahead normally through the window, the missed packets should fill in from this window
+	assert.True(t, b.Update(l, 59))
+	assert.True(t, b.Update(l, 60))
+	assert.True(t, b.Update(l, 61))
+	assert.True(t, b.Update(l, 62))
+	assert.True(t, b.Update(l, 63))
+	assert.True(t, b.Update(l, 64))
+	assert.True(t, b.Update(l, 65))
+	assert.True(t, b.Update(l, 66))
+	assert.True(t, b.Update(l, 67))
+	// 68 packets tracked, 32 seen, 36 missed
+	assert.Equal(t, int64(36), b.lostCounter.Count())
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 }
 
 func TestBitsLostCounterIssue1(t *testing.T) {
 	l := test.NewLogger()
-	b := NewBits(16)
+	b := NewBits(10)
 	b.lostCounter.Clear()
 	b.dupeCounter.Clear()
 	b.outOfWindowCounter.Clear()
 
-	// Receive 4, backfill 1, then 9, 2, 3, 5, 6, 7 (skip 8), 10, 11, 14.
-	// Then jump to 25 — slot 25%16=9 is being evicted, but it had been set
-	// (we received packet 9), so no spurious lost increment. The original
-	// regression was about double-counting a missing packet when its slot
-	// got cleared on a jump. With the jump path now using clearRange's
-	// word-level wasSet count, the same semantics hold.
 	assert.True(t, b.Update(l, 4))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 1))
@@ -266,7 +244,7 @@ func TestBitsLostCounterIssue1(t *testing.T) {
 	assert.Equal(t, int64(0), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 7))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
-	// Skip packet 8.
+	// assert.True(t, b.Update(l, 8))
 	assert.True(t, b.Update(l, 10))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 11))
@@ -274,23 +252,9 @@ func TestBitsLostCounterIssue1(t *testing.T) {
 
 	assert.True(t, b.Update(l, 14))
 	assert.Equal(t, int64(0), b.lostCounter.Count())
-
-	// Jump to 25. With length=16, slot 25%16=9 corresponds to packet 9
-	// (which we DID receive), so its bit is set and no lost++ from that
-	// eviction. The trace below shows the only loss is packet 8.
-	assert.True(t, b.Update(l, 25))
-	// current was 14, i=25. end=min(25,30)=25. count=11. startPos=15.
-	// steady? current=14<16, so warmup branch: per-bit n=15..25, count those
-	// with !get(n) AND n>16. n=17..25 are >16. Among slots 17%16=1..25%16=9
-	// did we set slots 1..9 (packets 1..9)? Yes for all but slot 8 (packet 8
-	// was skipped). n=24 maps to slot 8 which is FALSE → lost++. All other
-	// n in 17..25 map to slots that are set. n=16 is not strictly > 16. So
-	// lost = 1.
+	// Issue seems to be here, we reset missing packet 8 to false here and don't increment the lost counter
+	assert.True(t, b.Update(l, 19))
 	assert.Equal(t, int64(1), b.lostCounter.Count())
-
-	// Fill in 12, 13, 15, 16. Each is below current=25 (in-window). 16 must
-	// recheck slot 0 — it was set by NewBits and then cleared by the
-	// Update(25) jump, so 16 backfills cleanly.
 	assert.True(t, b.Update(l, 12))
 	assert.Equal(t, int64(1), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 13))
@@ -299,140 +263,29 @@ func TestBitsLostCounterIssue1(t *testing.T) {
 	assert.Equal(t, int64(1), b.lostCounter.Count())
 	assert.True(t, b.Update(l, 16))
 	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 17))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 18))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 20))
+	assert.Equal(t, int64(1), b.lostCounter.Count())
+	assert.True(t, b.Update(l, 21))
 
-	// We missed packet 8 above and that loss is still recorded once, never
-	// double-counted, never zeroed.
+	// We missed packet 8 above
 	assert.Equal(t, int64(1), b.lostCounter.Count())
 	assert.Equal(t, int64(0), b.dupeCounter.Count())
 	assert.Equal(t, int64(0), b.outOfWindowCounter.Count())
 }
 
-// TestBitsWarmupOvershoot exercises the jump path's warmup arm with an
-// overshoot past one full window. NewBits leaves current=0 with only slot 0
-// "set" by the marker. Jumping straight to length+k must (a) clear every
-// slot the jump straddles, (b) count only past-window slack (not the
-// in-window slots, which never had a "lost" tenant during warmup), and
-// (c) leave the cursor at the new counter so subsequent unit advances
-// count from steady state. The marker bit at slot 0 is irrelevant once
-// current >= length.
-func TestBitsWarmupOvershoot(t *testing.T) {
-	l := test.NewLogger()
-	b := NewBits(16)
-	b.lostCounter.Clear()
-
-	// Jump from current=0 to i=20 (length=16, overshoot=4).
-	// Warmup arm: counts slots in [1..16] where bit unset and n>length.
-	// Only n=16 was unset and >length: but slot 16%16=0 is the marker,
-	// so b.get(16) reads bits[0]=1 and skips. Result: 0 lost from the loop.
-	// Past-window: i - current - length = 20 - 0 - 16 = 4 lost.
-	assert.True(t, b.Update(l, 20))
-	assert.Equal(t, int64(4), b.lostCounter.Count())
-	assert.Equal(t, uint64(20), b.current)
-
-	// Steady state now (current=20 >= length=16). Unit advance to 21
-	// stomps slot 21%16=5, which was cleared by the jump and not reset,
-	// so this is +1 lost.
-	assert.True(t, b.Update(l, 21))
-	assert.Equal(t, int64(5), b.lostCounter.Count())
-}
-
-// TestBitsCheckAcrossWarmupBoundary pins the underflow trick in Check's
-// in-window clause. While in warmup, b.current-b.length underflows uint64
-// to a huge value so the first OR-clause is always false; the second
-// clause (i < length && current < length) carries the in-window check.
-// Once current >= length the regimes flip cleanly.
-func TestBitsCheckAcrossWarmupBoundary(t *testing.T) {
-	l := test.NewLogger()
-	b := NewBits(16)
-
-	// Warmup: current=0. Check(0) must read the marker (set) and return false.
-	assert.False(t, b.Check(l, 0), "marker slot should look already-received")
-	// Warmup: any 0 < i < length is in-window and unset → accepted.
-	for i := uint64(1); i < 16; i++ {
-		assert.True(t, b.Check(l, i), "warmup in-window i=%d should be accepted", i)
-	}
-	// Warmup: i >= length but > current is "next number" so accepted.
-	assert.True(t, b.Check(l, 16))
-	assert.True(t, b.Check(l, 1_000_000))
-
-	// Cross into steady state.
-	assert.True(t, b.Update(l, 100))
-	// Now current=100, length=16. In-window range is [85..100].
-	// 84 is just outside: the underflow clause activates; 84 > 100-16=84 is false.
-	// And the warmup clause is false (current >= length). So out of window.
-	assert.False(t, b.Check(l, 84))
-	// 85 sits at the boundary. 85 > 84 is true → in window, unset → accept.
-	assert.True(t, b.Check(l, 85))
-	// 100 is current itself; not strictly greater, in-window, but already set.
-	assert.False(t, b.Check(l, 100))
-	// Way out: clearly out of window.
-	assert.False(t, b.Check(l, 50))
-}
-
-// TestBitsMarkerInvariant verifies the seeded bits[0]=1 marker behaves
-// correctly across warmup and beyond. Update should never clear the marker
-// during warmup (clearRange skips position 0 when startPos=1), and once
-// current >= length the marker is no longer consulted by Check/Update on
-// the live path — but it must still report counter 0 as a duplicate while
-// we are in warmup.
-func TestBitsMarkerInvariant(t *testing.T) {
-	l := test.NewLogger()
-	b := NewBits(8)
-
-	// Counter 0 is the seeded marker; Check sees it as already received.
-	assert.False(t, b.Check(l, 0))
-	// Update(0) at current=0 hits the duplicate branch.
-	b.dupeCounter.Clear()
-	assert.False(t, b.Update(l, 0))
-	assert.Equal(t, int64(1), b.dupeCounter.Count())
-
-	// Walk forward through warmup; the marker must remain set.
-	for n := uint64(1); n <= 7; n++ {
-		assert.True(t, b.Update(l, n))
-	}
-	// Position 0 (the marker) should still read as set because we never
-	// cleared it; Update(0) still looks like a duplicate.
-	assert.False(t, b.Check(l, 0))
-
-	// Cross into steady state with a unit advance to 8: pos=0, evicts the
-	// marker bit. The lost-counter guard (i > b.length) is false (8 == 8),
-	// so this advance does NOT charge a lost packet — exactly what the
-	// marker is there to prevent.
-	b.lostCounter.Clear()
-	assert.True(t, b.Update(l, 8))
-	assert.Equal(t, int64(0), b.lostCounter.Count())
-	// The slot at pos 0 is now occupied by counter 8.
-	assert.False(t, b.Check(l, 8))
-}
-
-// BenchmarkBitsUpdateInOrder is the steady-state hot path: each call is
-// i == current+1.
-func BenchmarkBitsUpdateInOrder(b *testing.B) {
-	l := test.NewLogger()
-	z := NewBits(16384)
+func BenchmarkBits(b *testing.B) {
+	z := NewBits(10)
 	for n := 0; n < b.N; n++ {
-		z.Update(l, uint64(n)+1)
-	}
-}
+		for i := range z.bits {
+			z.bits[i] = true
+		}
+		for i := range z.bits {
+			z.bits[i] = false
+		}
 
-// BenchmarkBitsUpdateReorder simulates light reorder within the window:
-// every other packet arrives one slot behind its predecessor (forces the
-// in-window backfill branch).
-func BenchmarkBitsUpdateReorder(b *testing.B) {
-	l := test.NewLogger()
-	z := NewBits(16384)
-	for n := 0; n < b.N; n++ {
-		base := uint64(n) * 2
-		z.Update(l, base+2)
-		z.Update(l, base+1)
-	}
-}
-
-// BenchmarkBitsUpdateLargeJumps stresses the clearRange word-level path.
-func BenchmarkBitsUpdateLargeJumps(b *testing.B) {
-	l := test.NewLogger()
-	z := NewBits(16384)
-	for n := 0; n < b.N; n++ {
-		z.Update(l, uint64(n+1)*1000)
 	}
 }

cert/ca_pool.go

@@ -217,10 +217,6 @@ func (ncp *CAPool) verify(c Certificate, now time.Time, certFp string, signerFp
 		return nil, err
 	}
 
-	if signer.Certificate.Curve() != c.Curve() {
-		return nil, ErrCurveMismatch
-	}
-
 	if signer.Certificate.Expired(now) {
 		return nil, ErrRootExpired
 	}

cert/ca_pool_test.go

@@ -654,31 +654,3 @@ func TestCertificateV2_Verify_Subnets(t *testing.T) {
 	_, err = caPool.VerifyCertificate(time.Now(), c)
 	require.NoError(t, err)
 }
-
-func TestCertificateV2_CurveMismatch(t *testing.T) {
-	caIp1 := mustParsePrefixUnmapped("10.0.0.0/16")
-	caIp2 := mustParsePrefixUnmapped("192.168.0.0/24")
-	ca, _, caKey, _ := NewTestCaCert(Version2, Curve_P256, time.Now(), time.Now().Add(10*time.Minute), []netip.Prefix{caIp1, caIp2}, nil, []string{"test"})
-
-	caPem, err := ca.MarshalPEM()
-	require.NoError(t, err)
-
-	caPool := NewCAPool()
-	b, err := caPool.AddCAFromPEM(caPem)
-	require.NoError(t, err)
-	assert.Empty(t, b)
-
-	// ip is outside the network
-	cIp1 := mustParsePrefixUnmapped("10.0.0.1/24")
-	c, _, _, _ := NewTestCert(Version2, Curve_P256, ca, caKey, "test", time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{cIp1}, nil, []string{"test"})
-
-	fp, _ := c.Fingerprint()
-	_, err = caPool.verify(c, time.Now(), fp, c.Issuer())
-	require.NoError(t, err)
-	//
-	c2 := c.(*certificateV2)
-	c2.curve = Curve_CURVE25519
-	fp, _ = c.Fingerprint()
-	_, err = caPool.verify(c, time.Now(), fp, c.Issuer())
-	require.Error(t, err)
-}

cert/cert_v1.go

@@ -112,9 +112,6 @@ func (c *certificateV1) CheckSignature(key []byte) bool {
 	}
 	switch c.details.curve {
 	case Curve_CURVE25519:
-		if len(key) != ed25519.PublicKeySize {
-			return false //avoids a panic internal to ed25519
-		}
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
 		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)

cert/cert_v2.go

@@ -151,9 +151,6 @@ func (c *certificateV2) CheckSignature(key []byte) bool {
 
 	switch c.curve {
 	case Curve_CURVE25519:
-		if len(key) != ed25519.PublicKeySize {
-			return false //avoids a panic internal to ed25519
-		}
 		return ed25519.Verify(key, b, c.signature)
 	case Curve_P256:
 		pubKey, err := ecdsa.ParseUncompressedPublicKey(elliptic.P256(), key)

cert/errors.go

@@ -22,7 +22,6 @@ var (
 	ErrCaNotFound                 = errors.New("could not find ca for the certificate")
 	ErrUnknownVersion             = errors.New("certificate version unrecognized")
 	ErrCertPubkeyPresent          = errors.New("certificate has unexpected pubkey present")
-	ErrCurveMismatch              = errors.New("certificate curve does not match CA")
 
 	ErrInvalidPEMBlock                   = errors.New("input did not contain a valid PEM encoded block")
 	ErrInvalidPEMCertificateBanner       = errors.New("bytes did not contain a proper certificate banner")

connection_manager.go

@@ -11,6 +11,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/rcrowley/go-metrics"
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/header"
@@ -44,16 +45,19 @@ type connectionManager struct {
 	inactivityTimeout       atomic.Int64
 	dropInactive            atomic.Bool
 
+	metricsTxPunchy metrics.Counter
+
 	l *slog.Logger
 }
 
 func newConnectionManagerFromConfig(l *slog.Logger, c *config.C, hm *HostMap, p *Punchy) *connectionManager {
 	cm := &connectionManager{
-		hostMap:       hm,
-		l:             l,
-		punchy:        p,
-		relayUsed:     make(map[uint32]struct{}),
-		relayUsedLock: &sync.RWMutex{},
+		hostMap:         hm,
+		l:               l,
+		punchy:          p,
+		relayUsed:       make(map[uint32]struct{}),
+		relayUsedLock:   &sync.RWMutex{},
+		metricsTxPunchy: metrics.GetOrRegisterCounter("messages.tx.punchy", nil),
 	}
 
 	cm.reload(c, true)
@@ -149,8 +153,8 @@ func (cm *connectionManager) Start(ctx context.Context) {
 	defer clockSource.Stop()
 
 	p := []byte("")
-	nb := make([]byte, 12, 12)
-	out := make([]byte, mtu)
+	// Long-lived buf for the traffic-check goroutine; never released.
+	buf := cm.intf.bufAlloc.Acquire()
 
 	for {
 		select {
@@ -165,13 +169,13 @@ func (cm *connectionManager) Start(ctx context.Context) {
 					break
 				}
 
-				cm.doTrafficCheck(localIndex, p, nb, out, now)
+				cm.doTrafficCheck(localIndex, p, buf, now)
 			}
 		}
 	}
 }
 
-func (cm *connectionManager) doTrafficCheck(localIndex uint32, p, nb, out []byte, now time.Time) {
+func (cm *connectionManager) doTrafficCheck(localIndex uint32, p []byte, buf *WireBuffer, now time.Time) {
 	decision, hostinfo, primary := cm.makeTrafficDecision(localIndex, now)
 
 	switch decision {
@@ -195,7 +199,7 @@ func (cm *connectionManager) doTrafficCheck(localIndex uint32, p, nb, out []byte
 		cm.tryRehandshake(hostinfo)
 
 	case sendTestPacket:
-		cm.intf.SendMessageToHostInfo(header.Test, header.TestRequest, hostinfo, p, nb, out)
+		cm.intf.SendMessageToHostInfo(header.Test, header.TestRequest, hostinfo, p, buf)
 	}
 
 	cm.resetRelayTrafficCheck(hostinfo)
@@ -304,7 +308,9 @@ func (cm *connectionManager) migrateRelayUsed(oldhostinfo, newhostinfo *HostInfo
 		if err != nil {
 			cm.l.Error("failed to marshal Control message to migrate relay", "error", err)
 		} else {
-			cm.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, make([]byte, 12), make([]byte, mtu))
+			migBuf := cm.intf.bufAlloc.Acquire()
+			cm.intf.SendMessageToHostInfo(header.Control, 0, newhostinfo, msg, migBuf)
+			cm.intf.bufAlloc.Release(migBuf)
 			cm.l.Info("send CreateRelayRequest",
 				"relayFrom", req.RelayFromAddr,
 				"relayTo", req.RelayToAddr,
@@ -365,7 +371,7 @@ func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Tim
 
 		if !outTraffic {
 			// Send a punch packet to keep the NAT state alive
-			cm.punchy.SendPunch(hostinfo)
+			cm.sendPunch(hostinfo)
 		}
 
 		return decision, hostinfo, primary
@@ -396,16 +402,17 @@ func (cm *connectionManager) makeTrafficDecision(localIndex uint32, now time.Tim
 
 			// If we aren't sending or receiving traffic then its an unused tunnel and we don't to test the tunnel.
 			// Just maintain NAT state if configured to do so.
-			cm.punchy.SendPunch(hostinfo)
+			cm.sendPunch(hostinfo)
 			cm.trafficTimer.Add(hostinfo.localIndexId, cm.checkInterval)
 			return doNothing, nil, nil
 		}
 
-		// We aren't receiving traffic but we are sending it. The outbound
-		// traffic itself refreshes the primary remote's NAT state; this
-		// fans out to non-primary remotes, but only if target_all_remotes
-		// is configured.
-		cm.punchy.SendPunchToAll(hostinfo)
+		if cm.punchy.GetTargetEverything() {
+			// This is similar to the old punchy behavior with a slight optimization.
+			// We aren't receiving traffic but we are sending it, punch on all known
+			// ips in case we need to re-prime NAT state
+			cm.sendPunch(hostinfo)
+		}
 
 		if cm.l.Enabled(context.Background(), slog.LevelDebug) {
 			hostinfo.logger(cm.l).Debug("Tunnel status",
@@ -507,6 +514,31 @@ func (cm *connectionManager) isInvalidCertificate(now time.Time, hostinfo *HostI
 	}
 }
 
+func (cm *connectionManager) sendPunch(hostinfo *HostInfo) {
+	if !cm.punchy.GetPunch() {
+		// Punching is disabled
+		return
+	}
+
+	if cm.intf.lightHouse.IsAnyLighthouseAddr(hostinfo.vpnAddrs) {
+		// Do not punch to lighthouses, we assume our lighthouse update interval is good enough.
+		// In the event the update interval is not sufficient to maintain NAT state then a publicly available lighthouse
+		// would lose the ability to notify us and punchy.respond would become unreliable.
+		return
+	}
+
+	if cm.punchy.GetTargetEverything() {
+		hostinfo.remotes.ForEach(cm.hostMap.GetPreferredRanges(), func(addr netip.AddrPort, preferred bool) {
+			cm.metricsTxPunchy.Inc(1)
+			cm.intf.outside.WriteTo([]byte{1}, addr)
+		})
+
+	} else if hostinfo.remote.IsValid() {
+		cm.metricsTxPunchy.Inc(1)
+		cm.intf.outside.WriteTo([]byte{1}, hostinfo.remote)
+	}
+}
+
 func (cm *connectionManager) tryRehandshake(hostinfo *HostInfo) {
 	cs := cm.intf.pki.getCertState()
 	curCrt := hostinfo.ConnectionState.myCert

connection_manager_test.go

@@ -64,12 +64,12 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 
 	// Create manager
 	conf := config.NewC(test.NewLogger())
-	punchy := NewPunchyFromConfig(test.NewLogger(), conf, nil)
+	punchy := NewPunchyFromConfig(test.NewLogger(), conf)
 	nc := newConnectionManagerFromConfig(test.NewLogger(), conf, hostMap, punchy)
 	nc.intf = ifce
+
 	p := []byte("")
-	nb := make([]byte, 12, 12)
-	out := make([]byte, mtu)
+	buf := NewWireBuffer(mtu, 0)
 
 	// Add an ip we have established a connection w/ to hostmap
 	hostinfo := &HostInfo{
@@ -92,7 +92,7 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 	assert.True(t, hostinfo.in.Load())
 
 	// Do a traffic check tick, should not be pending deletion but should not have any in/out packets recorded
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.False(t, hostinfo.pendingDeletion.Load())
 	assert.False(t, hostinfo.out.Load())
 	assert.False(t, hostinfo.in.Load())
@@ -100,7 +100,7 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 	// Do another traffic check tick, this host should be pending deletion now
 	nc.Out(hostinfo)
 	assert.True(t, hostinfo.out.Load())
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.True(t, hostinfo.pendingDeletion.Load())
 	assert.False(t, hostinfo.out.Load())
 	assert.False(t, hostinfo.in.Load())
@@ -108,7 +108,7 @@ func Test_NewConnectionManagerTest(t *testing.T) {
 	assert.Contains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs[0])
 
 	// Do a final traffic check tick, the host should now be removed
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.NotContains(t, nc.hostMap.Hosts, hostinfo.vpnAddrs)
 	assert.NotContains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 }
@@ -146,12 +146,12 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 
 	// Create manager
 	conf := config.NewC(test.NewLogger())
-	punchy := NewPunchyFromConfig(test.NewLogger(), conf, nil)
+	punchy := NewPunchyFromConfig(test.NewLogger(), conf)
 	nc := newConnectionManagerFromConfig(test.NewLogger(), conf, hostMap, punchy)
 	nc.intf = ifce
+
 	p := []byte("")
-	nb := make([]byte, 12, 12)
-	out := make([]byte, mtu)
+	buf := NewWireBuffer(mtu, 0)
 
 	// Add an ip we have established a connection w/ to hostmap
 	hostinfo := &HostInfo{
@@ -174,14 +174,14 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 	assert.Contains(t, nc.hostMap.Indexes, hostinfo.localIndexId)
 
 	// Do a traffic check tick, should not be pending deletion but should not have any in/out packets recorded
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.False(t, hostinfo.pendingDeletion.Load())
 	assert.False(t, hostinfo.out.Load())
 	assert.False(t, hostinfo.in.Load())
 
 	// Do another traffic check tick, this host should be pending deletion now
 	nc.Out(hostinfo)
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.True(t, hostinfo.pendingDeletion.Load())
 	assert.False(t, hostinfo.out.Load())
 	assert.False(t, hostinfo.in.Load())
@@ -190,7 +190,7 @@ func Test_NewConnectionManagerTest2(t *testing.T) {
 
 	// We saw traffic, should no longer be pending deletion
 	nc.In(hostinfo)
-	nc.doTrafficCheck(hostinfo.localIndexId, p, nb, out, time.Now())
+	nc.doTrafficCheck(hostinfo.localIndexId, p, buf, time.Now())
 	assert.False(t, hostinfo.pendingDeletion.Load())
 	assert.False(t, hostinfo.out.Load())
 	assert.False(t, hostinfo.in.Load())
@@ -233,7 +233,7 @@ func Test_NewConnectionManager_DisconnectInactive(t *testing.T) {
 	conf.Settings["tunnels"] = map[string]any{
 		"drop_inactive": true,
 	}
-	punchy := NewPunchyFromConfig(test.NewLogger(), conf, nil)
+	punchy := NewPunchyFromConfig(test.NewLogger(), conf)
 	nc := newConnectionManagerFromConfig(test.NewLogger(), conf, hostMap, punchy)
 	assert.True(t, nc.dropInactive.Load())
 	nc.intf = ifce
@@ -358,7 +358,7 @@ func Test_NewConnectionManagerTest_DisconnectInvalid(t *testing.T) {
 
 	// Create manager
 	conf := config.NewC(test.NewLogger())
-	punchy := NewPunchyFromConfig(test.NewLogger(), conf, nil)
+	punchy := NewPunchyFromConfig(test.NewLogger(), conf)
 	nc := newConnectionManagerFromConfig(test.NewLogger(), conf, hostMap, punchy)
 	nc.intf = ifce
 	ifce.connectionManager = nc

connection_state.go

@@ -7,14 +7,13 @@ import (
 
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/handshake"
-	"github.com/slackhq/nebula/noiseutil"
 )
 
 const ReplayWindow = 1024
 
 type ConnectionState struct {
-	eKey           noiseutil.CipherState
-	dKey           noiseutil.CipherState
+	eKey           *NebulaCipherState
+	dKey           *NebulaCipherState
 	myCert         cert.Certificate
 	peerCert       *cert.CachedCertificate
 	initiator      bool
@@ -32,8 +31,8 @@ func newConnectionStateFromResult(r *handshake.Result) *ConnectionState {
 		myCert:    r.MyCert,
 		initiator: r.Initiator,
 		peerCert:  r.RemoteCert,
-		eKey:      noiseutil.NewCipherState(r.EKey, r.Cipher),
-		dKey:      noiseutil.NewCipherState(r.DKey, r.Cipher),
+		eKey:      NewNebulaCipherState(r.EKey),
+		dKey:      NewNebulaCipherState(r.DKey),
 		window:    NewBits(ReplayWindow),
 	}
 	ci.messageCounter.Add(r.MessageIndex)

control.go

@@ -278,15 +278,9 @@ func (c *Control) CloseTunnel(vpnIp netip.Addr, localOnly bool) bool {
 	}
 
 	if !localOnly {
-		c.f.send(
-			header.CloseTunnel,
-			0,
-			hostInfo.ConnectionState,
-			hostInfo,
-			[]byte{},
-			make([]byte, 12, 12),
-			make([]byte, mtu),
-		)
+		buf := c.f.bufAlloc.Acquire()
+		c.f.send(header.CloseTunnel, 0, hostInfo.ConnectionState, hostInfo, []byte{}, buf)
+		c.f.bufAlloc.Release(buf)
 	}
 
 	c.f.closeTunnel(hostInfo)
@@ -296,11 +290,14 @@ func (c *Control) CloseTunnel(vpnIp netip.Addr, localOnly bool) bool {
 // CloseAllTunnels is just like CloseTunnel except it goes through and shuts them all down, optionally you can avoid shutting down lighthouse tunnels
 // the int returned is a count of tunnels closed
 func (c *Control) CloseAllTunnels(excludeLighthouses bool) (closed int) {
+	// One WireBuffer for the whole shutdown loop.
+	buf := c.f.bufAlloc.Acquire()
+	defer c.f.bufAlloc.Release(buf)
 	shutdown := func(h *HostInfo) {
 		if excludeLighthouses && c.f.lightHouse.IsAnyLighthouseAddr(h.vpnAddrs) {
 			return
 		}
-		c.f.send(header.CloseTunnel, 0, h.ConnectionState, h, []byte{}, make([]byte, 12, 12), make([]byte, mtu))
+		c.f.send(header.CloseTunnel, 0, h.ConnectionState, h, []byte{}, buf)
 		c.f.closeTunnel(h)
 
 		c.l.Debug("Sending close tunnel message",

e2e/bench_test.go

@@ -0,0 +1,68 @@
+//go:build e2e_testing
+// +build e2e_testing
+
+package e2e
+
+import (
+	"testing"
+	"time"
+
+	"github.com/slackhq/nebula/cert"
+	"github.com/slackhq/nebula/cert_test"
+	"github.com/slackhq/nebula/e2e/router"
+)
+
+// BenchmarkHandshake measures end-to-end tunnel establishment time. The two
+// nodes and the router are constructed once before the loop so the timed window
+// is just the handshake itself: trigger packet -> handshake1 -> handshake2 ->
+// cached packet replay -> arrival on the remote TUN. Between iterations we
+// tear down both sides locally (no CloseTunnel notification on the wire) and
+// re-inject the lighthouse address that closeTunnel cleared, so the next
+// iteration runs through a fresh handshake against the same harness.
+func BenchmarkHandshake(b *testing.B) {
+	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version2, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
+
+	// Default try_interval is 100ms. The handshake manager schedules handshake1
+	// on its OutboundHandshakeTimer rather than firing immediately on trigger
+	// (the trigger channel only fast-paths static hosts), so a 100ms default
+	// drowns the actual handshake cost. Drop it to 1ms so the bench reflects
+	// the computation, not the wheel cadence.
+	bovr := m{"handshakes": m{"try_interval": "1ms"}}
+	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "me", "10.128.0.1/24", bovr)
+	theirControl, theirVpnIpNet, theirUdpAddr, _ := newSimpleServer(cert.Version2, ca, caKey, "them", "10.128.0.2/24", bovr)
+
+	myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+	theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+
+	myControl.Start()
+	theirControl.Start()
+	defer myControl.Stop()
+	defer theirControl.Stop()
+
+	r := router.NewR(b, myControl, theirControl)
+	r.CancelFlowLogs()
+	r.EnableFanIn()
+
+	trigger := BuildTunUDPPacket(theirVpnIpNet[0].Addr(), 80, myVpnIpNet[0].Addr(), 80, []byte("Hi from me"))
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for n := 0; n < b.N; n++ {
+		myControl.InjectTunPacket(trigger)
+		// RouteForAllUntilTxTun returns the moment the cached packet arrives at
+		// the remote TUN, which is also when both sides are fully established.
+		_ = r.RouteForAllUntilTxTun(theirControl)
+
+		b.StopTimer()
+		// Local-only close removes hostmap state on both sides without putting a
+		// CloseTunnel packet on the wire that we'd then have to drain. The
+		// closeTunnel path also clears learned lighthouse state for the peer
+		// when the last hostinfo for that addr goes away, so we re-inject.
+		myControl.CloseTunnel(theirVpnIpNet[0].Addr(), true)
+		theirControl.CloseTunnel(myVpnIpNet[0].Addr(), true)
+		myControl.InjectLightHouseAddr(theirVpnIpNet[0].Addr(), theirUdpAddr)
+		theirControl.InjectLightHouseAddr(myVpnIpNet[0].Addr(), myUdpAddr)
+		b.StartTimer()
+	}
+}

e2e/handshakes_test.go

@@ -165,7 +165,7 @@ func TestGoodHandshakeNoOverlap(t *testing.T) {
 
 	empty := []byte{}
 	t.Log("do something to cause a handshake")
-	myControl.GetF().SendMessageToVpnAddr(header.Test, header.MessageNone, theirVpnIpNet[0].Addr(), empty, empty, empty)
+	myControl.GetF().SendMessageToVpnAddr(header.Test, header.MessageNone, theirVpnIpNet[0].Addr(), empty, nebula.NewWireBuffer(9001, 0))
 
 	t.Log("Have them consume my stage 0 packet. They have a tunnel now")
 	theirControl.InjectUDPPacket(myControl.GetFromUDP(true))

e2e/helpers_test.go

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

e2e/leak_test.go

@@ -18,10 +18,14 @@ import (
 // retry mechanism gives the wg.Wait()-driven goroutines a moment to drain
 // before failing the assertion.
 //
-// Intentionally NOT t.Parallel()'d: concurrent tests would have their own
-// goroutines running and trip the assertion.
+// IgnoreCurrent is necessary in the parallelized suite: other tests can
+// leave goroutines mid-shutdown when this one runs (Stop is async, the
+// wg.Wait() drain is not blocking on test return). We're checking that
+// *this* test's setup tears down cleanly, not that the whole suite is
+// idle at this moment. Intentionally NOT t.Parallel()'d for the same
+// reason — concurrent test goroutines would always show up.
 func TestNoGoroutineLeaks(t *testing.T) {
-	defer goleak.VerifyNone(t)
+	defer goleak.VerifyNone(t, goleak.IgnoreCurrent())
 
 	ca, _, caKey, _ := cert_test.NewTestCaCert(cert.Version1, cert.Curve_CURVE25519, time.Now(), time.Now().Add(10*time.Minute), nil, nil, []string{})
 	myControl, myVpnIpNet, myUdpAddr, _ := newSimpleServer(cert.Version1, ca, caKey, "me", "10.128.0.1/24", nil)

e2e/sshd_test.go

@@ -1,125 +0,0 @@
-//go:build e2e_testing
-// +build e2e_testing
-
-package e2e
-
-import (
-	"crypto/ed25519"
-	"crypto/rand"
-	"encoding/pem"
-	"net"
-	"strings"
-	"testing"
-	"time"
-
-	"github.com/slackhq/nebula/cert"
-	"github.com/slackhq/nebula/cert_test"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"golang.org/x/crypto/ssh"
-)
-
-func TestSSHDLifecycle(t *testing.T) {
-	// TestSSHDLifecycle exercises the in-process sshd through several config reloads and a Control.Stop.
-	ca, _, caKey, _ := cert_test.NewTestCaCert(
-		cert.Version1, cert.Curve_CURVE25519,
-		time.Now(), time.Now().Add(10*time.Minute),
-		nil, nil, []string{},
-	)
-
-	hostKeyPEM := generateSSHHostKey(t)
-	clientSigner, clientAuthKey := generateSSHClientKey(t)
-	sshdAddr := allocLoopbackPort(t)
-
-	overrides := m{
-		"sshd": m{
-			"enabled":  true,
-			"listen":   sshdAddr,
-			"host_key": hostKeyPEM,
-			"authorized_users": []m{{
-				"user": "tester",
-				"keys": []string{clientAuthKey},
-			}},
-		},
-	}
-	control, _, _, _ := newSimpleServer(cert.Version1, ca, caKey, "sshd-test", "10.222.0.1/24", overrides)
-	control.Start()
-	t.Cleanup(func() { control.Stop() })
-
-	// sshd binds in a goroutine after Start returns; wait for it.
-	require.Eventually(t, func() bool { return canDial(sshdAddr) }, 2*time.Second, 25*time.Millisecond,
-		"sshd never started listening")
-
-	for i := 1; i <= 3; i++ {
-		out := sshExecReload(t, sshdAddr, clientSigner)
-		assert.Contains(t, out, "Reloading config", "reload cycle %d", i)
-		require.Eventually(t, func() bool { return canDial(sshdAddr) }, 2*time.Second, 25*time.Millisecond,
-			"sshd not listening after reload cycle %d", i)
-	}
-
-	control.Stop()
-	require.Eventually(t, func() bool { return !canDial(sshdAddr) }, 2*time.Second, 25*time.Millisecond,
-		"sshd still listening after Control.Stop")
-}
-
-func canDial(addr string) bool {
-	c, err := net.DialTimeout("tcp", addr, 100*time.Millisecond)
-	if err != nil {
-		return false
-	}
-	_ = c.Close()
-	return true
-}
-
-// allocLoopbackPort grabs an unused TCP port on 127.0.0.1, closes it, and returns the address. There
-// is a small race between releasing the port and the sshd reclaiming it; in practice the OS keeps the
-// port available long enough for the test to bind it.
-func allocLoopbackPort(t *testing.T) string {
-	t.Helper()
-	l, err := net.Listen("tcp", "127.0.0.1:0")
-	require.NoError(t, err)
-	addr := l.Addr().String()
-	require.NoError(t, l.Close())
-	return addr
-}
-
-func generateSSHHostKey(t *testing.T) string {
-	t.Helper()
-	_, priv, err := ed25519.GenerateKey(rand.Reader)
-	require.NoError(t, err)
-	block, err := ssh.MarshalPrivateKey(priv, "nebula-e2e-host")
-	require.NoError(t, err)
-	return string(pem.EncodeToMemory(block))
-}
-
-func generateSSHClientKey(t *testing.T) (ssh.Signer, string) {
-	t.Helper()
-	_, priv, err := ed25519.GenerateKey(rand.Reader)
-	require.NoError(t, err)
-	signer, err := ssh.NewSignerFromKey(priv)
-	require.NoError(t, err)
-	auth := strings.TrimSpace(string(ssh.MarshalAuthorizedKey(signer.PublicKey())))
-	return signer, auth
-}
-
-func sshExecReload(t *testing.T, addr string, signer ssh.Signer) string {
-	t.Helper()
-	cfg := &ssh.ClientConfig{
-		User:            "tester",
-		Auth:            []ssh.AuthMethod{ssh.PublicKeys(signer)},
-		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
-		Timeout:         2 * time.Second,
-	}
-	client, err := ssh.Dial("tcp", addr, cfg)
-	require.NoError(t, err)
-	defer client.Close()
-
-	sess, err := client.NewSession()
-	require.NoError(t, err)
-	defer sess.Close()
-
-	// reload tears the channel down before sending exit-status, so Output returns an error on the
-	// channel close. The output buffer still has whatever the reload callback wrote before that.
-	out, _ := sess.Output("reload")
-	return string(out)
-}

examples/config.yml

@@ -138,14 +138,6 @@ listen:
   # max, net.core.rmem_max and net.core.wmem_max
   #read_buffer: 10485760
   #write_buffer: 10485760
-
-  # On Windows only
-  # When true, Nebula installs a WFP (Windows Filtering Platform) PERMIT filter scoped to UDP at the listener port.
-  # WFP sits below Windows Defender Firewall, so this lets peer handshakes reach Nebula's outside socket regardless
-  # of WDF's inbound rules.
-  # Default true; set to false to leave WDF in charge of inbound decisions on the listener port. Not reloadable.
-  #windows_bypass_wdf: true
-
   # By default, Nebula replies to packets it has no tunnel for with a "recv_error" packet. This packet helps speed up reconnection
   # in the case that Nebula on either side did not shut down cleanly. This response can be abused as a way to discover if Nebula is running
   # on a host though. This option lets you configure if you want to send "recv_error" packets always, never, or only to private network remotes.
@@ -171,21 +163,17 @@ listen:
 
 punchy:
   # Continues to punch inbound/outbound at a regular interval to avoid expiration of firewall nat mappings
-  # This setting is reloadable.
   punch: true
 
   # respond means that a node you are trying to reach will connect back out to you if your hole punching fails
   # this is extremely useful if one node is behind a difficult nat, such as a symmetric NAT
   # Default is false
-  # This setting is reloadable.
   #respond: true
 
   # delays a punch response for misbehaving NATs, default is 1 second.
-  # This setting is reloadable.
   #delay: 1s
 
   # set the delay before attempting punchy.respond. Default is 5 seconds. respond must be true to take effect.
-  # This setting is reloadable.
   #respond_delay: 5s
 
 # Cipher allows you to choose between the available ciphers for your network. Options are chachapoly or aes
@@ -294,24 +282,6 @@ tun:
     #  metric: 100
     #  install: true
 
-  # On Windows only, sets the network category of the nebula interface. Without this, Windows often
-  # leaves the network as "Unidentified" and treats it as Public, which makes the host firewall more
-  # restrictive than you usually want for an overlay between trusted peers. Valid values:
-  #   private             - treat the nebula network as a private/trusted network (default)
-  #   public              - treat it as a public/untrusted network
-  #   domain              - treat it as a domain-authenticated network
-  #   unset               - leave whatever Windows decided alone
-  # Not reloadable.
-  #network_category: private
-
-  # On Windows only
-  # When true, Nebula installs a WFP (Windows Filtering Platform) PERMIT filter scoped to the nebula adapter LUID.
-  # WFP sits below Windows Defender Firewall, so this lets inbound traffic through regardless of WDF rules.
-  # Filters are auto-removed when the adapter goes away.
-  # See listen.windows_bypass_wdf for the matching control over inbound to nebula's outside UDP listener.
-  # Default true; set to false to leave WDF in charge of inbound decisions on the nebula interface. Not reloadable.
-  #windows_bypass_wdf: true
-
   # On linux only, set to true to manage unsafe routes directly on the system route table with gateway routes instead of
   # in nebula configuration files. Default false, not reloadable.
   #use_system_route_table: false

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 v0.26.1
+	github.com/gaissmai/bart v0.26.0
 	github.com/gogo/protobuf v1.3.2
 	github.com/google/gopacket v1.1.19
 	github.com/kardianos/service v1.2.4
@@ -26,7 +26,7 @@ require (
 	go.yaml.in/yaml/v3 v3.0.4
 	golang.org/x/crypto v0.50.0
 	golang.org/x/exp v0.0.0-20230725093048-515e97ebf090
-	golang.org/x/net v0.53.0
+	golang.org/x/net v0.52.0
 	golang.org/x/sync v0.20.0
 	golang.org/x/sys v0.43.0
 	golang.org/x/term v0.42.0

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 v0.26.1 h1:+w4rnLGNlA2GDVn382Tfe3jOsK5vOr5n4KmigJ9lbTo=
-github.com/gaissmai/bart v0.26.1/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
+github.com/gaissmai/bart v0.26.0 h1:xOZ57E9hJLBiQaSyeZa9wgWhGuzfGACgqp4BE77OkO0=
+github.com/gaissmai/bart v0.26.0/go.mod h1:GREWQfTLRWz/c5FTOsIw+KkscuFkIV5t8Rp7Nd1Td5c=
 github.com/go-kit/kit v0.8.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2as=
 github.com/go-kit/log v0.1.0/go.mod h1:zbhenjAZHb184qTLMA9ZjW7ThYL0H2mk7Q6pNt4vbaY=
@@ -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 v0.53.0 h1:d+qAbo5L0orcWAr0a9JweQpjXF19LMXJE8Ey7hwOdUA=
-golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
+golang.org/x/net v0.52.0 h1:He/TN1l0e4mmR3QqHMT2Xab3Aj3L9qjbhRm78/6jrW0=
+golang.org/x/net v0.52.0/go.mod h1:R1MAz7uMZxVMualyPXb+VaqGSa3LIaUqk0eEt3w36Sw=
 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=

handshake/machine.go

@@ -31,7 +31,6 @@ type CertVerifier func(cert.Certificate) (*cert.CachedCertificate, error)
 type Result struct {
 	EKey          *noise.CipherState
 	DKey          *noise.CipherState
-	Cipher        noise.CipherFunc // identifies which post-handshake CipherState the data plane should wrap EKey/DKey in
 	MyCert        cert.Certificate
 	RemoteCert    *cert.CachedCertificate
 	RemoteIndex   uint32
@@ -106,7 +105,6 @@ func NewMachine(
 		myVersion:  version,
 		result: &Result{
 			Initiator: initiator,
-			Cipher:    cred.cipherSuite,
 		},
 	}, nil
 }

handshake_manager.go

@@ -971,12 +971,11 @@ func (hm *HandshakeManager) continueHandshake(via ViaSender, hh *HandshakeHostIn
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			hostinfo.logger(f.l).Debug("Sending stored packets", "count", len(hh.packetStore))
 		}
-		nb := make([]byte, 12, 12)
-		out := make([]byte, mtu)
+		buf := f.bufAlloc.Acquire()
 		for _, cp := range hh.packetStore {
-			//todo use a sendbatcher
-			cp.callback(cp.messageType, cp.messageSubType, hostinfo, cp.packet, nb, out)
+			cp.callback(cp.messageType, cp.messageSubType, hostinfo, cp.packet, buf)
 		}
+		f.bufAlloc.Release(buf)
 		f.cachedPacketMetrics.sent.Inc(int64(len(hh.packetStore)))
 	}
 
@@ -1086,7 +1085,9 @@ func (hm *HandshakeManager) sendHandshakeResponse(via ViaSender, msg []byte, hos
 		// We received a valid handshake on this relay, so make sure the relay
 		// state reflects that, in case it had been marked Disestablished.
 		via.relayHI.relayState.UpdateRelayForByIdxState(via.remoteIdx, Established)
-		f.SendVia(via.relayHI, via.relay, msg, make([]byte, 12), make([]byte, mtu), false)
+		buf := f.bufAlloc.Acquire()
+		f.SendVia(via.relayHI, via.relay, msg, buf)
+		f.bufAlloc.Release(buf)
 		f.l.Info("Handshake message sent", append(logFields, "relay", via.relayHI.vpnAddrs[0])...)
 	}
 }
@@ -1103,7 +1104,9 @@ func (hm *HandshakeManager) handleCheckAndCompleteError(err error, existing, hos
 	switch err {
 	case ErrAlreadySeen:
 		if existing.SetRemoteIfPreferred(f.hostMap, via) {
-			f.SendMessageToVpnAddr(header.Test, header.TestRequest, hostinfo.vpnAddrs[0], []byte(""), make([]byte, 12, 12), make([]byte, mtu))
+			buf := f.bufAlloc.Acquire()
+			f.SendMessageToVpnAddr(header.Test, header.TestRequest, hostinfo.vpnAddrs[0], []byte(""), buf)
+			f.bufAlloc.Release(buf)
 		}
 		// Resend the original response. The peer is committed to that response's
 		// ephemeral keys; a freshly-built one would have different keys and break
@@ -1126,7 +1129,9 @@ func (hm *HandshakeManager) handleCheckAndCompleteError(err error, existing, hos
 			"responderIndex", hostinfo.localIndexId,
 			"handshake", hsFields,
 		)
-		f.SendMessageToVpnAddr(header.Test, header.TestRequest, hostinfo.vpnAddrs[0], []byte(""), make([]byte, 12, 12), make([]byte, mtu))
+		buf := f.bufAlloc.Acquire()
+		f.SendMessageToVpnAddr(header.Test, header.TestRequest, hostinfo.vpnAddrs[0], []byte(""), buf)
+		f.bufAlloc.Release(buf)
 
 	case ErrLocalIndexCollision:
 		f.l.Error("Failed to add HostInfo due to localIndex collision",

handshake_manager_test.go

@@ -80,15 +80,15 @@ func testCountTimerWheelEntries(tw *LockingTimerWheel[netip.Addr]) (c int) {
 type mockEncWriter struct {
 }
 
-func (mw *mockEncWriter) SendMessageToVpnAddr(_ header.MessageType, _ header.MessageSubType, _ netip.Addr, _, _, _ []byte) {
+func (mw *mockEncWriter) SendMessageToVpnAddr(_ header.MessageType, _ header.MessageSubType, _ netip.Addr, _ []byte, _ *WireBuffer) {
 	return
 }
 
-func (mw *mockEncWriter) SendVia(_ *HostInfo, _ *Relay, _, _, _ []byte, _ bool) {
+func (mw *mockEncWriter) SendVia(_ *HostInfo, _ *Relay, _ []byte, _ *WireBuffer) {
 	return
 }
 
-func (mw *mockEncWriter) SendMessageToHostInfo(_ header.MessageType, _ header.MessageSubType, _ *HostInfo, _, _, _ []byte) {
+func (mw *mockEncWriter) SendMessageToHostInfo(_ header.MessageType, _ header.MessageSubType, _ *HostInfo, _ []byte, _ *WireBuffer) {
 	return
 }
 

header/header.go

@@ -174,10 +174,6 @@ func (h *H) SubTypeName() string {
 	return SubTypeName(h.Type, h.Subtype)
 }
 
-func (h *H) IsValidSubType() bool {
-	return IsValidSubType(h.Type, h.Subtype)
-}
-
 // SubTypeName will transform a nebula message sub type into a human string
 func SubTypeName(t MessageType, s MessageSubType) string {
 	if n, ok := subTypeMap[t]; ok {
@@ -189,16 +185,6 @@ func SubTypeName(t MessageType, s MessageSubType) string {
 	return "unknown"
 }
 
-func IsValidSubType(t MessageType, s MessageSubType) bool {
-	if n, ok := subTypeMap[t]; ok {
-		if _, ok := (*n)[s]; ok {
-			return true
-		}
-	}
-
-	return false
-}
-
 // NewHeader turns bytes into a header
 func NewHeader(b []byte) (*H, error) {
 	h := new(H)

hostmap.go

@@ -308,7 +308,7 @@ type cachedPacket struct {
 	packet         []byte
 }
 
-type packetCallback func(t header.MessageType, st header.MessageSubType, h *HostInfo, p, nb, out []byte)
+type packetCallback func(t header.MessageType, st header.MessageSubType, h *HostInfo, p []byte, buf *WireBuffer)
 
 type cachedPacketMetrics struct {
 	sent    metrics.Counter
@@ -691,6 +691,7 @@ func (i *HostInfo) TryPromoteBest(preferredRanges []netip.Prefix, ifce *Interfac
 			}
 		}
 
+		buf := ifce.bufAlloc.Acquire()
 		i.remotes.ForEach(preferredRanges, func(addr netip.AddrPort, preferred bool) {
 			if remote.IsValid() && (!addr.IsValid() || !preferred) {
 				return
@@ -698,8 +699,9 @@ func (i *HostInfo) TryPromoteBest(preferredRanges []netip.Prefix, ifce *Interfac
 
 			// Try to send a test packet to that host, this should
 			// cause it to detect a roaming event and switch remotes
-			ifce.sendTo(header.Test, header.TestRequest, i.ConnectionState, i, addr, []byte(""), make([]byte, 12, 12), make([]byte, mtu))
+			ifce.sendTo(header.Test, header.TestRequest, i.ConnectionState, i, addr, []byte(""), buf)
 		})
+		ifce.bufAlloc.Release(buf)
 	}
 
 	// Re query our lighthouses for new remotes occasionally

inside.go

@@ -2,25 +2,19 @@ package nebula
 
 import (
 	"context"
-	"io"
 	"log/slog"
 	"net/netip"
 
 	"github.com/slackhq/nebula/firewall"
 	"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(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)
+func (f *Interface) consumeInsidePacket(buf *WireBuffer, q int, localCache firewall.ConntrackCache) {
+	packet := buf.IPPacket()
+
+	err := newPacket(packet, false, buf.FwPacket)
 	if err != nil {
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			f.l.Debug("Error while validating outbound packet",
@@ -33,21 +27,18 @@ func (f *Interface) consumeInsidePacket(pkt wire.TunPacket, fwPacket *firewall.P
 
 	// Ignore local broadcast packets
 	if f.dropLocalBroadcast {
-		if f.myBroadcastAddrsTable.Contains(fwPacket.RemoteAddr) {
+		if f.myBroadcastAddrsTable.Contains(buf.FwPacket.RemoteAddr) {
 			return
 		}
 	}
 
-	if f.myVpnAddrsTable.Contains(fwPacket.RemoteAddr) {
+	if f.myVpnAddrsTable.Contains(buf.FwPacket.RemoteAddr) {
 		// Immediately forward packets from self to self.
 		// This should only happen on Darwin-based and FreeBSD hosts, which
 		// routes packets from the Nebula addr to the Nebula addr through the Nebula
 		// TUN device.
 		if immediatelyForwardToSelf {
-			err := pkt.PerSegment(func(seg []byte) error {
-				_, werr := f.readers[q].Write(seg)
-				return werr
-			})
+			_, err := f.readers[q].Write(packet)
 			if err != nil {
 				f.l.Error("Failed to forward to tun", "error", err)
 			}
@@ -58,32 +49,20 @@ func (f *Interface) consumeInsidePacket(pkt wire.TunPacket, fwPacket *firewall.P
 	}
 
 	// Ignore multicast packets
-	if f.dropMulticast && fwPacket.RemoteAddr.IsMulticast() {
+	if f.dropMulticast && buf.FwPacket.RemoteAddr.IsMulticast() {
 		return
 	}
 
-	hostinfo, ready := f.getOrHandshakeConsiderRouting(fwPacket, func(hh *HandshakeHostInfo) {
-		// 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,
-			)
-		}
+	hostinfo, ready := f.getOrHandshakeConsiderRouting(buf.FwPacket, func(hh *HandshakeHostInfo) {
+		hh.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
 	})
 
 	if hostinfo == nil {
-		f.rejectInside(packet, rejectBuf, q)
+		f.rejectInside(packet, buf.Out, 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,
-				"fwPacket", fwPacket,
+				"vpnAddr", buf.FwPacket.RemoteAddr,
+				"fwPacket", buf.FwPacket,
 			)
 		}
 		return
@@ -93,138 +72,21 @@ func (f *Interface) consumeInsidePacket(pkt wire.TunPacket, fwPacket *firewall.P
 		return
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, false, hostinfo, f.pki.GetCAPool(), localCache)
+	dropReason := f.firewall.Drop(*buf.FwPacket, false, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason == nil {
-		f.sendInsideMessage(hostinfo, pkt, nb, sendBatch)
+		f.sendNoMetrics(header.Message, 0, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, packet, buf, q)
+
 	} else {
-		f.rejectInside(packet, rejectBuf, q)
+		f.rejectInside(packet, buf.Out, q)
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			hostinfo.logger(f.l).Debug("dropping outbound packet",
-				"fwPacket", fwPacket,
+				"fwPacket", buf.FwPacket,
 				"reason", dropReason,
 			)
 		}
 	}
 }
 
-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
@@ -241,27 +103,27 @@ func (f *Interface) rejectInside(packet []byte, out []byte, q int) {
 	}
 }
 
-func (f *Interface) rejectOutside(packet []byte, ci *ConnectionState, hostinfo *HostInfo, nb, out []byte, q int) {
+func (f *Interface) rejectOutside(packet []byte, ci *ConnectionState, hostinfo *HostInfo, scratch []byte, buf *WireBuffer, q int) {
 	if !f.firewall.OutSendReject {
 		return
 	}
 
-	out = iputil.CreateRejectPacket(packet, out)
-	if len(out) == 0 {
+	rejectIP := iputil.CreateRejectPacket(packet, scratch)
+	if len(rejectIP) == 0 {
 		return
 	}
 
-	if len(out) > iputil.MaxRejectPacketSize {
+	if len(rejectIP) > iputil.MaxRejectPacketSize {
 		if f.l.Enabled(context.Background(), slog.LevelInfo) {
 			f.l.Info("rejectOutside: packet too big, not sending",
 				"packet", packet,
-				"outPacket", out,
+				"outPacket", rejectIP,
 			)
 		}
 		return
 	}
 
-	f.sendNoMetrics(header.Message, 0, ci, hostinfo, netip.AddrPort{}, out, nb, packet, q)
+	f.sendNoMetrics(header.Message, 0, ci, hostinfo, netip.AddrPort{}, rejectIP, buf, q)
 }
 
 // Handshake will attempt to initiate a tunnel with the provided vpn address. This is a no-op if the tunnel is already established or being established
@@ -354,7 +216,7 @@ func (f *Interface) getOrHandshakeConsiderRouting(fwPacket *firewall.Packet, cac
 
 }
 
-func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p, nb, out []byte) {
+func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p []byte, buf *WireBuffer) {
 	fp := &firewall.Packet{}
 	err := newPacket(p, false, fp)
 	if err != nil {
@@ -374,12 +236,12 @@ func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubTyp
 		return
 	}
 
-	f.sendNoMetrics(header.Message, st, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, p, nb, out, 0)
+	f.sendNoMetrics(header.Message, st, hostinfo.ConnectionState, hostinfo, netip.AddrPort{}, p, buf, 0)
 }
 
 // SendMessageToVpnAddr handles real addr:port lookup and sends to the current best known address for vpnAddr.
 // This function ignores myVpnNetworksTable, and will always attempt to treat the address as a vpnAddr
-func (f *Interface) SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnAddr netip.Addr, p, nb, out []byte) {
+func (f *Interface) SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnAddr netip.Addr, p []byte, buf *WireBuffer) {
 	hostInfo, ready := f.handshakeManager.GetOrHandshake(vpnAddr, func(hh *HandshakeHostInfo) {
 		hh.cachePacket(f.l, t, st, p, f.SendMessageToHostInfo, f.cachedPacketMetrics)
 	})
@@ -397,128 +259,73 @@ func (f *Interface) SendMessageToVpnAddr(t header.MessageType, st header.Message
 		return
 	}
 
-	f.SendMessageToHostInfo(t, st, hostInfo, p, nb, out)
+	f.SendMessageToHostInfo(t, st, hostInfo, p, buf)
 }
 
-func (f *Interface) SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hi *HostInfo, p, nb, out []byte) {
-	f.send(t, st, hi.ConnectionState, hi, p, nb, out)
+func (f *Interface) SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hi *HostInfo, p []byte, buf *WireBuffer) {
+	f.send(t, st, hi.ConnectionState, hi, p, buf)
 }
 
-func (f *Interface) send(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, p, nb, out []byte) {
+func (f *Interface) send(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, p []byte, buf *WireBuffer) {
 	f.messageMetrics.Tx(t, st, 1)
-	f.sendNoMetrics(t, st, ci, hostinfo, netip.AddrPort{}, p, nb, out, 0)
+	f.sendNoMetrics(t, st, ci, hostinfo, netip.AddrPort{}, p, buf, 0)
 }
 
-func (f *Interface) sendTo(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote netip.AddrPort, p, nb, out []byte) {
+func (f *Interface) sendTo(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote netip.AddrPort, p []byte, buf *WireBuffer) {
 	f.messageMetrics.Tx(t, st, 1)
-	f.sendNoMetrics(t, st, ci, hostinfo, remote, p, nb, out, 0)
-}
-
-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()
-	}
-	c := via.ConnectionState.messageCounter.Add(1)
-
-	out = header.Encode(out, header.Version, header.Message, header.MessageRelay, relay.RemoteIndex, c)
-	f.connectionManager.Out(via)
-
-	// Authenticate the header and payload, but do not encrypt for this message type.
-	// The payload consists of the inner, unencrypted Nebula header, as well as the end-to-end encrypted payload.
-	if len(out)+len(ad)+via.ConnectionState.eKey.Overhead() > cap(out) {
-		if noiseutil.EncryptLockNeeded {
-			via.ConnectionState.writeLock.Unlock()
-		}
-		via.logger(f.l).Error("SendVia out buffer not large enough for relay",
-			"outCap", cap(out),
-			"payloadLen", len(ad),
-			"headerLen", len(out),
-			"cipherOverhead", via.ConnectionState.eKey.Overhead(),
-		)
-		return nil, io.ErrShortBuffer
-	}
-
-	// The header bytes are written to the 'out' slice; Grow the slice to hold the header and associated data payload.
-	offset := len(out)
-	out = out[:offset+len(ad)]
-
-	// In one call path, the associated data _is_ already stored in out. In other call paths, the associated data must
-	// be copied into 'out'.
-	if !nocopy {
-		copy(out[offset:], ad)
-	}
-
-	var err error
-	out, err = via.ConnectionState.eKey.EncryptDanger(out, out, nil, c, nb)
-	if noiseutil.EncryptLockNeeded {
-		via.ConnectionState.writeLock.Unlock()
-	}
-	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
+	f.sendNoMetrics(t, st, ci, hostinfo, remote, p, buf, 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,
-	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)
+//
+// via is the HostInfo through which the message is relayed. ad is staged into
+// the inner-payload slot of buf and then AAD-only sealed under via's key by
+// SealRelayInPlace. The sendNoMetrics relay-forward path skips this entry
+// point and calls sendViaInPlace directly because its inner ciphertext is
+// already in place from the encrypt step.
+func (f *Interface) SendVia(via *HostInfo, relay *Relay, ad []byte, buf *WireBuffer) {
+	if header.Len+len(ad)+via.ConnectionState.eKey.Overhead() > cap(buf.Out) {
+		via.logger(f.l).Error("SendVia out buffer not large enough for relay",
+			"outCap", cap(buf.Out),
+			"payloadLen", len(ad),
+			"headerLen", header.Len,
+			"cipherOverhead", via.ConnectionState.eKey.Overhead(),
+		)
 		return
 	}
-	err = f.writers[0].WriteTo(toSend, via.remote)
-	if err != nil {
-		via.logger(f.l).Info("Failed to WriteTo in sendVia", "error", err)
-	}
+	buf.StageRelayInner(ad)
+	f.sendViaInPlace(via, relay, len(ad), buf)
 }
 
-func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote netip.AddrPort, p, nb, out []byte, q int) {
+// sendViaInPlace stamps the outer relay header, AAD-seals over the [outer
+// header | inner-already-staged] region, and writes the result to via.remote.
+// Called from SendVia (after staging ad) and from sendNoMetrics' relay-forward
+// path (where the inner ciphertext is already in place from SealForRelay).
+func (f *Interface) sendViaInPlace(via *HostInfo, relay *Relay, innerLen int, buf *WireBuffer) {
+	f.connectionManager.Out(via)
+	out, err := buf.SealRelayInPlace(via.ConnectionState, relay.RemoteIndex, innerLen)
+	if err != nil {
+		via.logger(f.l).Info("Failed to EncryptDanger in sendVia", "error", err)
+		return
+	}
+	if err := f.writers[0].WriteTo(out, via.remote); err != nil {
+		via.logger(f.l).Info("Failed to WriteTo in sendVia", "error", err)
+	}
+	f.connectionManager.RelayUsed(relay.LocalIndex)
+}
+
+// sendNoMetrics encrypts and writes one outbound nebula packet (data, control,
+// lighthouse, etc) using buf as the per-call wire scratch. When the hostinfo
+// has no direct remote we encrypt into the relay-reserved slot via
+// SealForRelay so sendViaInPlace can wrap it without an extra copy.
+func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote netip.AddrPort, p []byte, buf *WireBuffer, q int) {
 	if ci.eKey == nil {
 		return
 	}
 	useRelay := !remote.IsValid() && !hostinfo.remote.IsValid()
-	fullOut := out
 
-	if useRelay {
-		if len(out) < header.Len {
-			// out always has a capacity of mtu, but not always a length greater than the header.Len.
-			// Grow it to make sure the next operation works.
-			out = out[:header.Len]
-		}
-		// Save a header's worth of data at the front of the 'out' buffer.
-		out = out[header.Len:]
-	}
-
-	if noiseutil.EncryptLockNeeded {
-		// NOTE: for goboring AESGCMTLS we need to lock because of the nonce check
-		ci.writeLock.Lock()
-	}
-	c := ci.messageCounter.Add(1)
-
-	//l.WithField("trace", string(debug.Stack())).Error("out Header ", &Header{Version, t, st, 0, hostinfo.remoteIndexId, c}, p)
-	out = header.Encode(out, header.Version, t, st, hostinfo.remoteIndexId, c)
 	f.connectionManager.Out(hostinfo)
 
 	// Query our LH if we haven't since the last time we've been rebound, this will cause the remote to punch against
@@ -535,50 +342,42 @@ func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType
 		}
 	}
 
+	var out []byte
 	var err error
-	out, err = ci.eKey.EncryptDanger(out, out, p, c, nb)
-	if noiseutil.EncryptLockNeeded {
-		ci.writeLock.Unlock()
+	if useRelay {
+		out, err = buf.SealForRelay(ci, t, st, hostinfo.remoteIndexId, p)
+	} else {
+		out, err = buf.Seal(ci, t, st, hostinfo.remoteIndexId, p)
 	}
 	if err != nil {
 		hostinfo.logger(f.l).Error("Failed to encrypt outgoing packet",
 			"error", err,
 			"udpAddr", remote,
-			"counter", c,
-			"attemptedCounter", c,
 		)
 		return
 	}
 
-	if remote.IsValid() {
-		err = f.writers[q].WriteTo(out, remote)
-		if err != nil {
-			hostinfo.logger(f.l).Error("Failed to write outgoing packet",
-				"error", err,
-				"udpAddr", remote,
-			)
+	switch {
+	case remote.IsValid():
+		if err := f.writers[q].WriteTo(out, remote); err != nil {
+			hostinfo.logger(f.l).Error("Failed to write outgoing packet", "error", err, "udpAddr", remote)
 		}
-	} else if hostinfo.remote.IsValid() {
-		err = f.writers[q].WriteTo(out, hostinfo.remote)
-		if err != nil {
-			hostinfo.logger(f.l).Error("Failed to write outgoing packet",
-				"error", err,
-				"udpAddr", remote,
-			)
+	case hostinfo.remote.IsValid():
+		if err := f.writers[q].WriteTo(out, hostinfo.remote); err != nil {
+			hostinfo.logger(f.l).Error("Failed to write outgoing packet", "error", err, "udpAddr", hostinfo.remote)
 		}
-	} else {
-		// Try to send via a relay
+	default:
+		// SealForRelay placed the inner ciphertext at buf.Out[header.Len:],
+		// so sendViaInPlace can wrap it with the outer relay header without
+		// an extra copy.
 		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,
-				)
+				hostinfo.logger(f.l).Info("sendNoMetrics failed to find HostInfo", "relay", relayIP, "error", err)
 				continue
 			}
-			f.SendVia(relayHostInfo, relay, out, nb, fullOut[:header.Len+len(out)], true)
+			f.sendViaInPlace(relayHostInfo, relay, len(out), buf)
 			break
 		}
 	}

interface.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/netip"
 	"sync"
@@ -12,15 +13,11 @@ import (
 
 	"github.com/gaissmai/bart"
 	"github.com/rcrowley/go-metrics"
-	"github.com/slackhq/nebula/util"
-	"github.com/slackhq/nebula/wire"
 
 	"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"
 )
 
@@ -40,7 +37,6 @@ type InterfaceConfig struct {
 	DropLocalBroadcast bool
 	DropMulticast      bool
 	routines           int
-	batchSize          int
 	MessageMetrics     *MessageMetrics
 	version            string
 	relayManager       *relayManager
@@ -73,7 +69,6 @@ type Interface struct {
 	dropLocalBroadcast    bool
 	dropMulticast         bool
 	routines              int
-	batchSize             int
 	disconnectInvalid     atomic.Bool
 	closed                atomic.Bool
 	relayManager          *relayManager
@@ -93,12 +88,8 @@ type Interface struct {
 
 	ctx     context.Context
 	writers []udp.Conn
-	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
+	readers []io.ReadWriteCloser
+	wg      sync.WaitGroup
 
 	// fatalErr holds the first unexpected reader error that caused shutdown.
 	// nil means "no fatal error" (yet)
@@ -110,19 +101,19 @@ type Interface struct {
 	messageMetrics      *MessageMetrics
 	cachedPacketMetrics *cachedPacketMetrics
 
+	// bufAlloc hands out reusable WireBuffers sized for this interface's
+	// inside Device. All buf consumers (hot-path data-plane goroutines,
+	// long-lived workers, and cold callers) acquire from here so sizing
+	// is centralized and consistent. Long-lived owners just don't release.
+	bufAlloc WireBufferAllocator
+
 	l *slog.Logger
 }
 
 type EncWriter interface {
-	SendVia(via *HostInfo,
-		relay *Relay,
-		ad,
-		nb,
-		out []byte,
-		nocopy bool,
-	)
-	SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnAddr netip.Addr, p, nb, out []byte)
-	SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p, nb, out []byte)
+	SendVia(via *HostInfo, relay *Relay, ad []byte, buf *WireBuffer)
+	SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnAddr netip.Addr, p []byte, buf *WireBuffer)
+	SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p []byte, buf *WireBuffer)
 	Handshake(vpnAddr netip.Addr)
 	GetHostInfo(vpnAddr netip.Addr) *HostInfo
 	GetCertState() *CertState
@@ -194,11 +185,9 @@ 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([]tio.Queue, c.routines),
-		batchers:              make([]batch.RxBatcher, c.routines),
+		readers:               make([]io.ReadWriteCloser, c.routines),
 		myVpnNetworks:         cs.myVpnNetworks,
 		myVpnNetworksTable:    cs.myVpnNetworksTable,
 		myVpnAddrs:            cs.myVpnAddrs,
@@ -215,6 +204,8 @@ func NewInterface(ctx context.Context, c *InterfaceConfig) (*Interface, error) {
 			dropped: metrics.GetOrRegisterCounter("hostinfo.cached_packets.dropped", nil),
 		},
 
+		bufAlloc: NewWireBufferPool(mtu, c.Inside.TunPrefixLen()),
+
 		l: c.l,
 	}
 
@@ -256,17 +247,15 @@ 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 {
-			if err = f.inside.NewMultiQueueReader(); err != nil {
+			reader, err = f.inside.NewMultiQueueReader()
+			if err != nil {
 				return err
 			}
 		}
-	}
-	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.readers[i] = reader
 	}
 
 	f.wg.Add(1) // for us to wait on Close() to return
@@ -324,21 +313,12 @@ func (f *Interface) listenOut(i int) {
 
 	ctCache := firewall.NewConntrackCacheTicker(f.ctx, f.l, f.conntrackCacheTimeout)
 	lhh := f.lightHouse.NewRequestHandler()
-	h := &header.H{}
-	fwPacket := &firewall.Packet{}
-	nb := make([]byte, 12, 12)
+	// Long-lived per-receive-goroutine buf; never released back to the pool.
+	buf := f.bufAlloc.Acquire()
 
-	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)
+	err := li.ListenOut(func(fromUdpAddr netip.AddrPort, payload []byte) {
+		f.readOutsidePackets(ViaSender{UdpAddr: fromUdpAddr}, buf, payload, lhh, i, ctCache.Get())
+	})
 
 	if err != nil && !f.closed.Load() {
 		f.l.Error("Error while reading inbound packet, closing", "error", err)
@@ -348,38 +328,25 @@ func (f *Interface) listenOut(i int) {
 	f.l.Debug("underlay reader is done", "reader", i)
 }
 
-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)
-
+func (f *Interface) listenIn(reader io.ReadWriteCloser, i int) {
+	// Long-lived per-tun-reader buf; never released back to the pool.
+	buf := f.bufAlloc.Acquire()
 	conntrackCache := firewall.NewConntrackCacheTicker(f.ctx, f.l, f.conntrackCacheTimeout)
 
 	for {
-		n, err := reader.Read(packets, packetMem)
+		_, err := buf.ReadIPFromTUN(reader)
 		if err != nil {
 			if !f.closed.Load() {
-				f.l.Error("Error while reading outbound packet, closing", "error", err, "reader", q)
+				f.l.Error("Error while reading outbound packet, closing", "error", err, "reader", i)
 				f.onFatal(err)
 			}
 			break
 		}
 
-		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.consumeInsidePacket(buf, i, conntrackCache.Get())
 	}
 
-	f.l.Debug("overlay reader is done", "reader", q)
+	f.l.Debug("overlay reader is done", "reader", i)
 }
 
 func (f *Interface) RegisterConfigChangeCallbacks(c *config.C) {

lighthouse.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/gaissmai/bart"
+	"github.com/rcrowley/go-metrics"
 	"github.com/slackhq/nebula/cert"
 	"github.com/slackhq/nebula/config"
 	"github.com/slackhq/nebula/header"
@@ -34,6 +35,7 @@ type LightHouse struct {
 
 	myVpnNetworks      []netip.Prefix
 	myVpnNetworksTable *bart.Lite
+	punchConn          udp.Conn
 	punchy             *Punchy
 
 	// Local cache of answers from light houses
@@ -61,7 +63,11 @@ type LightHouse struct {
 	interval     atomic.Int64
 	updateCancel context.CancelFunc
 	ifce         EncWriter
-	nebulaPort   uint32 // 32 bits because protobuf does not have a uint16
+	// bufAlloc lets the lighthouse query/update workers, request handlers
+	// and punchback goroutines acquire correctly sized WireBuffers from
+	// the same pool as the data plane. Set by main.go alongside ifce.
+	bufAlloc   WireBufferAllocator
+	nebulaPort uint32 // 32 bits because protobuf does not have a uint16
 
 	advertiseAddrs atomic.Pointer[[]netip.AddrPort]
 
@@ -73,8 +79,9 @@ type LightHouse struct {
 
 	calculatedRemotes atomic.Pointer[bart.Table[[]*calculatedRemote]] // Maps VpnAddr to []*calculatedRemote
 
-	metrics *MessageMetrics
-	l       *slog.Logger
+	metrics           *MessageMetrics
+	metricHolepunchTx metrics.Counter
+	l                 *slog.Logger
 }
 
 // NewLightHouseFromConfig will build a Lighthouse struct from the values provided in the config object
@@ -102,10 +109,15 @@ func NewLightHouseFromConfig(ctx context.Context, l *slog.Logger, c *config.C, c
 		myVpnNetworksTable: cs.myVpnNetworksTable,
 		addrMap:            make(map[netip.Addr]*RemoteList),
 		nebulaPort:         nebulaPort,
+		punchConn:          pc,
 		punchy:             p,
 		updateTrigger:      make(chan struct{}, 1),
 		queryChan:          make(chan netip.Addr, c.GetUint32("handshakes.query_buffer", 64)),
-		l:                  l,
+		// Default to a no-prefix pool so the query/update workers and
+		// request handlers have a working WireBufferAllocator before
+		// main.go wires up the real one from the Interface.
+		bufAlloc: NewWireBufferPool(mtu, 0),
+		l:        l,
 	}
 	lighthouses := make([]netip.Addr, 0)
 	h.lighthouses.Store(&lighthouses)
@@ -114,6 +126,9 @@ func NewLightHouseFromConfig(ctx context.Context, l *slog.Logger, c *config.C, c
 
 	if c.GetBool("stats.lighthouse_metrics", false) {
 		h.metrics = newLighthouseMetrics()
+		h.metricHolepunchTx = metrics.GetOrRegisterCounter("messages.tx.holepunch", nil)
+	} else {
+		h.metricHolepunchTx = metrics.NilCounter{}
 	}
 
 	err := h.reload(c, true)
@@ -751,21 +766,22 @@ func (lh *LightHouse) startQueryWorker() {
 	}
 
 	go func() {
-		nb := make([]byte, 12, 12)
-		out := make([]byte, mtu)
+		// Long-lived per-worker WireBuffer; reused for every lighthouse query
+		// this worker issues for the life of the goroutine.
+		buf := lh.bufAlloc.Acquire()
 
 		for {
 			select {
 			case <-lh.ctx.Done():
 				return
 			case addr := <-lh.queryChan:
-				lh.innerQueryServer(addr, nb, out)
+				lh.innerQueryServer(addr, buf)
 			}
 		}
 	}()
 }
 
-func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
+func (lh *LightHouse) innerQueryServer(addr netip.Addr, buf *WireBuffer) {
 	if lh.IsLighthouseAddr(addr) {
 		return
 	}
@@ -814,7 +830,7 @@ func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
 				}
 			}
 
-			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v1Query, nb, out)
+			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v1Query, buf)
 			queried++
 
 		} else if v == cert.Version2 {
@@ -833,7 +849,7 @@ func (lh *LightHouse) innerQueryServer(addr netip.Addr, nb, out []byte) {
 				}
 			}
 
-			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v2Query, nb, out)
+			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v2Query, buf)
 			queried++
 
 		} else {
@@ -862,8 +878,12 @@ func (lh *LightHouse) StartUpdateWorker() {
 	go func() {
 		defer clockSource.Stop()
 
+		// Long-lived per-worker WireBuffer; reused across every periodic
+		// update for the life of this goroutine.
+		buf := lh.bufAlloc.Acquire()
+
 		for {
-			lh.SendUpdate()
+			lh.sendUpdate(buf)
 
 			select {
 			case <-updateCtx.Done():
@@ -877,6 +897,15 @@ func (lh *LightHouse) StartUpdateWorker() {
 	}()
 }
 
+// SendUpdate is the public entry point that triggers a one-shot lighthouse
+// update outside the worker loop (e.g. tests or reload paths). It allocates
+// its own WireBuffer since callers don't already own one.
+func (lh *LightHouse) SendUpdate() {
+	buf := lh.bufAlloc.Acquire()
+	defer lh.bufAlloc.Release(buf)
+	lh.sendUpdate(buf)
+}
+
 // TriggerUpdate requests an immediate lighthouse update. This is a non-blocking
 // operation intended to be called after a handshake completes with a lighthouse,
 // so the lighthouse has our current addresses without waiting for the next
@@ -888,7 +917,7 @@ func (lh *LightHouse) TriggerUpdate() {
 	}
 }
 
-func (lh *LightHouse) SendUpdate() {
+func (lh *LightHouse) sendUpdate(buf *WireBuffer) {
 	var v4 []*V4AddrPort
 	var v6 []*V6AddrPort
 
@@ -914,9 +943,6 @@ func (lh *LightHouse) SendUpdate() {
 		}
 	}
 
-	nb := make([]byte, 12, 12)
-	out := make([]byte, mtu)
-
 	var v1Update, v2Update []byte
 	var err error
 	updated := 0
@@ -967,7 +993,7 @@ func (lh *LightHouse) SendUpdate() {
 				}
 			}
 
-			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v1Update, nb, out)
+			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v1Update, buf)
 			updated++
 
 		} else if v == cert.Version2 {
@@ -996,7 +1022,7 @@ func (lh *LightHouse) SendUpdate() {
 				}
 			}
 
-			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v2Update, nb, out)
+			lh.ifce.SendMessageToVpnAddr(header.LightHouse, 0, lhVpnAddr, v2Update, buf)
 			updated++
 
 		} else {
@@ -1012,9 +1038,11 @@ func (lh *LightHouse) SendUpdate() {
 }
 
 type LightHouseHandler struct {
-	lh   *LightHouse
-	nb   []byte
-	out  []byte
+	lh *LightHouse
+	// buf is the long-lived per-handler wire scratch. NewRequestHandler is
+	// called once per data-plane receive goroutine, so buf is owned by that
+	// goroutine and reused for every lighthouse send the handler issues.
+	buf  *WireBuffer
 	pb   []byte
 	meta *NebulaMeta
 	l    *slog.Logger
@@ -1023,8 +1051,7 @@ type LightHouseHandler struct {
 func (lh *LightHouse) NewRequestHandler() *LightHouseHandler {
 	lhh := &LightHouseHandler{
 		lh:  lh,
-		nb:  make([]byte, 12, 12),
-		out: make([]byte, mtu),
+		buf: lh.bufAlloc.Acquire(),
 		l:   lh.l,
 		pb:  make([]byte, mtu),
 
@@ -1161,7 +1188,7 @@ func (lhh *LightHouseHandler) handleHostQuery(n *NebulaMeta, fromVpnAddrs []neti
 	}
 
 	lhh.lh.metricTx(NebulaMeta_HostQueryReply, 1)
-	w.SendMessageToVpnAddr(header.LightHouse, 0, fromVpnAddrs[0], lhh.pb[:ln], lhh.nb, lhh.out[:0])
+	w.SendMessageToVpnAddr(header.LightHouse, 0, fromVpnAddrs[0], lhh.pb[:ln], lhh.buf)
 
 	lhh.sendHostPunchNotification(n, fromVpnAddrs, queryVpnAddr, w)
 }
@@ -1221,7 +1248,7 @@ func (lhh *LightHouseHandler) sendHostPunchNotification(n *NebulaMeta, fromVpnAd
 	}
 
 	lhh.lh.metricTx(NebulaMeta_HostPunchNotification, 1)
-	w.SendMessageToVpnAddr(header.LightHouse, 0, punchNotifDest, lhh.pb[:ln], lhh.nb, lhh.out[:0])
+	w.SendMessageToVpnAddr(header.LightHouse, 0, punchNotifDest, lhh.pb[:ln], lhh.buf)
 }
 
 func (lhh *LightHouseHandler) coalesceAnswers(v cert.Version, c *cache, n *NebulaMeta) {
@@ -1378,7 +1405,7 @@ func (lhh *LightHouseHandler) handleHostUpdateNotification(n *NebulaMeta, fromVp
 	}
 
 	lhh.lh.metricTx(NebulaMeta_HostUpdateNotificationAck, 1)
-	w.SendMessageToVpnAddr(header.LightHouse, 0, fromVpnAddrs[0], lhh.pb[:ln], lhh.nb, lhh.out[:0])
+	w.SendMessageToVpnAddr(header.LightHouse, 0, fromVpnAddrs[0], lhh.pb[:ln], lhh.buf)
 }
 
 func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpnAddrs []netip.Addr, w EncWriter) {
@@ -1399,25 +1426,61 @@ func (lhh *LightHouseHandler) handleHostPunchNotification(n *NebulaMeta, fromVpn
 		return
 	}
 
+	empty := []byte{0}
+	punch := func(vpnPeer netip.AddrPort, logVpnAddr netip.Addr) {
+		if !vpnPeer.IsValid() {
+			return
+		}
+
+		go func() {
+			time.Sleep(lhh.lh.punchy.GetDelay())
+			lhh.lh.metricHolepunchTx.Inc(1)
+			lhh.lh.punchConn.WriteTo(empty, vpnPeer)
+		}()
+
+		if lhh.l.Enabled(context.Background(), slog.LevelDebug) {
+			lhh.l.Debug("Punching",
+				"vpnPeer", vpnPeer,
+				"logVpnAddr", logVpnAddr,
+			)
+		}
+	}
+
 	remoteAllowList := lhh.lh.GetRemoteAllowList()
 	for _, a := range n.Details.V4AddrPorts {
 		b := protoV4AddrPortToNetAddrPort(a)
 		if remoteAllowList.Allow(detailsVpnAddr, b.Addr()) {
-			lhh.lh.punchy.Schedule(b, detailsVpnAddr)
+			punch(b, detailsVpnAddr)
 		}
 	}
 
 	for _, a := range n.Details.V6AddrPorts {
 		b := protoV6AddrPortToNetAddrPort(a)
 		if remoteAllowList.Allow(detailsVpnAddr, b.Addr()) {
-			lhh.lh.punchy.Schedule(b, detailsVpnAddr)
+			punch(b, detailsVpnAddr)
 		}
 	}
 
 	// This sends a nebula test packet to the host trying to contact us. In the case
 	// of a double nat or other difficult scenario, this may help establish
-	// a tunnel. ScheduleRespond is a no-op when punchy.respond is disabled.
-	lhh.lh.punchy.ScheduleRespond(detailsVpnAddr)
+	// a tunnel.
+	if lhh.lh.punchy.GetRespond() {
+		go func() {
+			time.Sleep(lhh.lh.punchy.GetRespondDelay())
+			if lhh.l.Enabled(context.Background(), slog.LevelDebug) {
+				lhh.l.Debug("Sending a nebula test packet",
+					"vpnAddr", detailsVpnAddr,
+				)
+			}
+			// We acquire and release a fresh buf within this goroutine so it
+			// returns to the pool once the punchback send completes. We
+			// should move this into a timerwheel or a single goroutine
+			// managed by a channel.
+			pbuf := lhh.lh.bufAlloc.Acquire()
+			defer lhh.lh.bufAlloc.Release(pbuf)
+			w.SendMessageToVpnAddr(header.Test, header.TestRequest, detailsVpnAddr, []byte(""), pbuf)
+		}()
+	}
 }
 
 func protoAddrToNetAddr(addr *Addr) netip.Addr {

lighthouse_test.go

@@ -372,12 +372,12 @@ type testEncWriter struct {
 	protocolVersion cert.Version
 }
 
-func (tw *testEncWriter) SendVia(via *HostInfo, relay *Relay, ad, nb, out []byte, nocopy bool) {
+func (tw *testEncWriter) SendVia(via *HostInfo, relay *Relay, ad []byte, buf *WireBuffer) {
 }
 func (tw *testEncWriter) Handshake(vpnIp netip.Addr) {
 }
 
-func (tw *testEncWriter) SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p, _, _ []byte) {
+func (tw *testEncWriter) SendMessageToHostInfo(t header.MessageType, st header.MessageSubType, hostinfo *HostInfo, p []byte, _ *WireBuffer) {
 	msg := &NebulaMeta{}
 	err := msg.Unmarshal(p)
 	if tw.metaFilter == nil || msg.Type == *tw.metaFilter {
@@ -394,7 +394,7 @@ func (tw *testEncWriter) SendMessageToHostInfo(t header.MessageType, st header.M
 	}
 }
 
-func (tw *testEncWriter) SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnIp netip.Addr, p, _, _ []byte) {
+func (tw *testEncWriter) SendMessageToVpnAddr(t header.MessageType, st header.MessageSubType, vpnIp netip.Addr, p []byte, _ *WireBuffer) {
 	msg := &NebulaMeta{}
 	err := msg.Unmarshal(p)
 	if tw.metaFilter == nil || msg.Type == *tw.metaFilter {

main.go

@@ -55,7 +55,7 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 	}
 	l.Info("Firewall started", "firewallHashes", fw.GetRuleHashes())
 
-	ssh, err := sshd.NewSSHServer(ctx, l.With("subsystem", "sshd"))
+	ssh, err := sshd.NewSSHServer(l.With("subsystem", "sshd"))
 	if err != nil {
 		return nil, util.ContextualizeIfNeeded("Error while creating SSH server", err)
 	}
@@ -170,7 +170,7 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 	}
 
 	hostMap := NewHostMapFromConfig(l, c)
-	punchy := NewPunchyFromConfig(l, c, udpConns[0])
+	punchy := NewPunchyFromConfig(l, c)
 	connManager := newConnectionManagerFromConfig(l, c, hostMap, punchy)
 	lightHouse, err := NewLightHouseFromConfig(ctx, l, c, pki.getCertState(), udpConns[0], punchy)
 	if err != nil {
@@ -215,7 +215,6 @@ 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),
@@ -233,6 +232,7 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 
 		ifce.writers = udpConns
 		lightHouse.ifce = ifce
+		lightHouse.bufAlloc = ifce.bufAlloc
 
 		ifce.RegisterConfigChangeCallbacks(c)
 		ifce.reloadDisconnectInvalid(c)
@@ -241,8 +241,6 @@ func Main(c *config.C, configTest bool, buildVersion string, l *slog.Logger, dev
 
 		handshakeManager.f = ifce
 		go handshakeManager.Run(ctx)
-
-		punchy.Start(ctx, ifce, hostMap, lightHouse)
 	}
 
 	stats, err := newStatsServerFromConfig(ctx, l, c, buildVersion, configTest)

message_metrics.go

@@ -13,8 +13,6 @@ type MessageMetrics struct {
 
 	rxUnknown metrics.Counter
 	txUnknown metrics.Counter
-
-	rxInvalid metrics.Counter
 }
 
 func (m *MessageMetrics) Rx(t header.MessageType, s header.MessageSubType, i int64) {
@@ -35,11 +33,6 @@ func (m *MessageMetrics) Tx(t header.MessageType, s header.MessageSubType, i int
 		}
 	}
 }
-func (m *MessageMetrics) RxInvalid(i int64) {
-	if m != nil && m.rxInvalid != nil {
-		m.rxInvalid.Inc(i)
-	}
-}
 
 func newMessageMetrics() *MessageMetrics {
 	gen := func(t string) [][]metrics.Counter {
@@ -63,7 +56,6 @@ func newMessageMetrics() *MessageMetrics {
 
 		rxUnknown: metrics.GetOrRegisterCounter("messages.rx.other", nil),
 		txUnknown: metrics.GetOrRegisterCounter("messages.tx.other", nil),
-		rxInvalid: metrics.GetOrRegisterCounter("messages.rx.invalid", nil),
 	}
 }
 

noise.go

@@ -0,0 +1,86 @@
+package nebula
+
+import (
+	"crypto/cipher"
+	"encoding/binary"
+	"errors"
+
+	"github.com/flynn/noise"
+)
+
+type endianness interface {
+	PutUint64(b []byte, v uint64)
+}
+
+var noiseEndianness endianness = binary.BigEndian
+
+// NonceSize is the AEAD nonce length used by all ciphers nebula supports
+// today (AES-GCM and ChaCha20-Poly1305 both use 96-bit nonces). Encrypt-
+// and DecryptDanger lay out the nonce as 4 zero bytes followed by an 8-byte
+// big-endian counter; if a future cipher with a different nonce size is
+// added, this constant and those layouts must change together.
+const NonceSize = 12
+
+// AEADOverhead is the AEAD authentication tag length the ciphers nebula
+// supports append to ciphertext. Both AES-GCM and ChaCha20-Poly1305 use
+// 128-bit tags. NebulaCipherState.Overhead() returns this dynamically from
+// the cipher; the constant is for sizing buffers at construction time.
+const AEADOverhead = 16
+
+type NebulaCipherState struct {
+	c cipher.AEAD
+}
+
+func NewNebulaCipherState(s *noise.CipherState) *NebulaCipherState {
+	x := s.Cipher()
+	return &NebulaCipherState{c: x.(cipher.AEAD)}
+}
+
+// EncryptDanger encrypts and authenticates a given payload.
+//
+// out is a destination slice to hold the output of the EncryptDanger operation.
+//   - ad is additional data, which will be authenticated and appended to out, but not encrypted.
+//   - plaintext is encrypted, authenticated and appended to out.
+//   - n is a nonce value which must never be re-used with this key.
+//   - nb is a buffer used for temporary storage in the implementation of this call, which should
+//     be re-used by callers to minimize garbage collection.
+func (s *NebulaCipherState) EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error) {
+	if s != nil {
+		// TODO: Is this okay now that we have made messageCounter atomic?
+		// Alternative may be to split the counter space into ranges
+		//if n <= s.n {
+		//	return nil, errors.New("CRITICAL: a duplicate counter value was used")
+		//}
+		//s.n = n
+		nb[0] = 0
+		nb[1] = 0
+		nb[2] = 0
+		nb[3] = 0
+		noiseEndianness.PutUint64(nb[4:], n)
+		out = s.c.Seal(out, nb, plaintext, ad)
+		//l.Debugf("Encryption: outlen: %d, nonce: %d, ad: %s, plainlen %d", len(out), n, ad, len(plaintext))
+		return out, nil
+	} else {
+		return nil, errors.New("no cipher state available to encrypt")
+	}
+}
+
+func (s *NebulaCipherState) DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error) {
+	if s != nil {
+		nb[0] = 0
+		nb[1] = 0
+		nb[2] = 0
+		nb[3] = 0
+		noiseEndianness.PutUint64(nb[4:], n)
+		return s.c.Open(out, nb, ciphertext, ad)
+	} else {
+		return []byte{}, nil
+	}
+}
+
+func (s *NebulaCipherState) Overhead() int {
+	if s != nil {
+		return s.c.Overhead()
+	}
+	return 0
+}

noiseutil/aesgcm.go

@@ -1,53 +0,0 @@
-package noiseutil
-
-import (
-	"crypto/cipher"
-	"encoding/binary"
-	"errors"
-
-	"github.com/flynn/noise"
-)
-
-// CipherStateAESGCM is the data-plane wrapper for the AES-GCM AEAD cipher.
-// AES-GCM uses big-endian nonce encoding per the Noise spec.
-type CipherStateAESGCM struct {
-	c cipher.AEAD
-}
-
-// NewCipherStateAESGCM extracts the underlying AEAD from the post-handshake noise.CipherState.
-// The caller is responsible for ensuring the noise cipher is actually AES-GCM,
-// otherwise the type assertion still succeeds but the nonce endianness will be wrong on the wire.
-func NewCipherStateAESGCM(s *noise.CipherState) *CipherStateAESGCM {
-	return &CipherStateAESGCM{c: s.Cipher().(cipher.AEAD)}
-}
-
-func (s *CipherStateAESGCM) EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error) {
-	if s == nil {
-		return nil, errors.New("no cipher state available to encrypt")
-	}
-	nb[0] = 0
-	nb[1] = 0
-	nb[2] = 0
-	nb[3] = 0
-	binary.BigEndian.PutUint64(nb[4:], n)
-	return s.c.Seal(out, nb, plaintext, ad), nil
-}
-
-func (s *CipherStateAESGCM) DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error) {
-	if s == nil {
-		return []byte{}, nil
-	}
-	nb[0] = 0
-	nb[1] = 0
-	nb[2] = 0
-	nb[3] = 0
-	binary.BigEndian.PutUint64(nb[4:], n)
-	return s.c.Open(out, nb, ciphertext, ad)
-}
-
-func (s *CipherStateAESGCM) Overhead() int {
-	if s == nil {
-		return 0
-	}
-	return s.c.Overhead()
-}

noiseutil/chachapoly.go

@@ -1,52 +0,0 @@
-package noiseutil
-
-import (
-	"crypto/cipher"
-	"encoding/binary"
-	"errors"
-
-	"github.com/flynn/noise"
-)
-
-// CipherStateChaChaPoly is the data-plane wrapper for the ChaCha20-Poly1305 AEAD cipher.
-// ChaCha20-Poly1305 uses little-endian nonce encoding per the Noise spec.
-type CipherStateChaChaPoly struct {
-	c cipher.AEAD
-}
-
-// NewCipherStateChaChaPoly extracts the underlying AEAD from the post-handshake noise.CipherState.
-// The caller is responsible for ensuring the noise cipher is actually ChaCha20-Poly1305.
-func NewCipherStateChaChaPoly(s *noise.CipherState) *CipherStateChaChaPoly {
-	return &CipherStateChaChaPoly{c: s.Cipher().(cipher.AEAD)}
-}
-
-func (s *CipherStateChaChaPoly) EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error) {
-	if s == nil {
-		return nil, errors.New("no cipher state available to encrypt")
-	}
-	nb[0] = 0
-	nb[1] = 0
-	nb[2] = 0
-	nb[3] = 0
-	binary.LittleEndian.PutUint64(nb[4:], n)
-	return s.c.Seal(out, nb, plaintext, ad), nil
-}
-
-func (s *CipherStateChaChaPoly) DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error) {
-	if s == nil {
-		return []byte{}, nil
-	}
-	nb[0] = 0
-	nb[1] = 0
-	nb[2] = 0
-	nb[3] = 0
-	binary.LittleEndian.PutUint64(nb[4:], n)
-	return s.c.Open(out, nb, ciphertext, ad)
-}
-
-func (s *CipherStateChaChaPoly) Overhead() int {
-	if s == nil {
-		return 0
-	}
-	return s.c.Overhead()
-}

noiseutil/cipher_state.go

@@ -1,40 +0,0 @@
-package noiseutil
-
-import (
-	"fmt"
-
-	"github.com/flynn/noise"
-)
-
-// CipherState is the post-handshake AEAD cipher used for the data plane.
-// Each supported cipher has its own concrete implementation in this package with the nonce endianness hardcoded,
-// so the encrypt/decrypt fast path avoids interface dispatch on the byte order.
-type CipherState interface {
-	// EncryptDanger encrypts and authenticates a given payload.
-	//
-	// out is a destination slice to hold the output of the EncryptDanger operation.
-	//   - ad is additional data, which will be authenticated and appended to out, but not encrypted.
-	//   - plaintext is encrypted, authenticated and appended to out.
-	//   - n is a nonce value which must never be re-used with this key.
-	//   - nb is a scratch buffer used to assemble the nonce.
-	EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error)
-
-	// DecryptDanger authenticates and decrypts a given payload, with the same argument shape as EncryptDanger.
-	DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error)
-
-	// Overhead returns the AEAD tag size, or 0 if the receiver is nil.
-	Overhead() int
-}
-
-// NewCipherState wraps the post-handshake noise.CipherState in the per-cipher type that matches cipherFunc.
-// cipherFunc must be the same cipher used to build the noise CipherSuite that produced s.
-func NewCipherState(s *noise.CipherState, cipherFunc noise.CipherFunc) CipherState {
-	switch cipherFunc.CipherName() {
-	case CipherAESGCM.CipherName():
-		return NewCipherStateAESGCM(s)
-	case noise.CipherChaChaPoly.CipherName():
-		return NewCipherStateChaChaPoly(s)
-	default:
-		panic(fmt.Sprintf("noiseutil: unsupported cipher %q", cipherFunc.CipherName()))
-	}
-}

noiseutil/cipher_state_test.go

@@ -1,222 +0,0 @@
-package noiseutil
-
-import (
-	"testing"
-
-	"github.com/flynn/noise"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestCipherStateAESGCMRoundtrip(t *testing.T) {
-	enc, dec := buildCipherStates(t, CipherAESGCM)
-	roundtrip(t, NewCipherStateAESGCM(enc), NewCipherStateAESGCM(dec))
-}
-
-func TestCipherStateChaChaPolyRoundtrip(t *testing.T) {
-	enc, dec := buildCipherStates(t, noise.CipherChaChaPoly)
-	roundtrip(t, NewCipherStateChaChaPoly(enc), NewCipherStateChaChaPoly(dec))
-}
-
-func TestNewCipherStateDispatch(t *testing.T) {
-	encA, _ := buildCipherStates(t, CipherAESGCM)
-	encC, _ := buildCipherStates(t, noise.CipherChaChaPoly)
-
-	assert.IsType(t, &CipherStateAESGCM{}, NewCipherState(encA, CipherAESGCM))
-	assert.IsType(t, &CipherStateChaChaPoly{}, NewCipherState(encC, noise.CipherChaChaPoly))
-}
-
-func TestNewCipherStateUnsupportedPanics(t *testing.T) {
-	enc, _ := buildCipherStates(t, CipherAESGCM)
-	assert.Panics(t, func() {
-		NewCipherState(enc, fakeCipher{})
-	})
-}
-
-type fakeCipher struct{}
-
-func (fakeCipher) Cipher(k [32]byte) noise.Cipher { return nil }
-func (fakeCipher) CipherName() string             { return "Fake" }
-
-// buildCipherStates runs an in-memory NN handshake with the requested cipher
-// to produce a pair of post-handshake CipherStates that share keys.
-func buildCipherStates(t *testing.T, c noise.CipherFunc) (*noise.CipherState, *noise.CipherState) {
-	t.Helper()
-	suite := noise.NewCipherSuite(noise.DH25519, c, noise.HashSHA256)
-	cfg := noise.Config{CipherSuite: suite, Pattern: noise.HandshakeNN}
-	cfg.Initiator = true
-	hsI, err := noise.NewHandshakeState(cfg)
-	require.NoError(t, err)
-	cfg.Initiator = false
-	hsR, err := noise.NewHandshakeState(cfg)
-	require.NoError(t, err)
-
-	msg, _, _, err := hsI.WriteMessage(nil, nil)
-	require.NoError(t, err)
-	_, _, _, err = hsR.ReadMessage(nil, msg)
-	require.NoError(t, err)
-
-	msg, dR, _, err := hsR.WriteMessage(nil, nil)
-	require.NoError(t, err)
-	_, eI, _, err := hsI.ReadMessage(nil, msg)
-	require.NoError(t, err)
-	require.NotNil(t, eI)
-	require.NotNil(t, dR)
-
-	// noise returns (cs1, cs2) where cs1 is the initiator->responder cipher.
-	return eI, dR
-}
-
-func roundtrip(t *testing.T, enc, dec CipherState) {
-	t.Helper()
-	plaintext := []byte("nebula cipher state roundtrip")
-	ad := []byte("aad")
-	nb := make([]byte, 12)
-
-	ct, err := enc.EncryptDanger(nil, ad, plaintext, 1, nb)
-	require.NoError(t, err)
-	assert.NotEqual(t, plaintext, ct)
-
-	pt, err := dec.DecryptDanger(nil, ad, ct, 1, nb)
-	require.NoError(t, err)
-	assert.Equal(t, plaintext, pt)
-
-	// Wrong nonce must fail authentication.
-	_, err = dec.DecryptDanger(nil, ad, ct, 2, nb)
-	require.Error(t, err)
-
-	assert.Equal(t, enc.Overhead(), dec.Overhead())
-	assert.Equal(t, 16, enc.Overhead())
-}
-
-func BenchmarkCipherStateEncryptAESGCM(b *testing.B) {
-	enc, _ := buildCipherStatesB(b, CipherAESGCM)
-	benchEncryptCipherState(b, NewCipherState(enc, CipherAESGCM))
-}
-
-func BenchmarkCipherStateEncryptChaChaPoly(b *testing.B) {
-	enc, _ := buildCipherStatesB(b, noise.CipherChaChaPoly)
-	benchEncryptCipherState(b, NewCipherState(enc, noise.CipherChaChaPoly))
-}
-
-func benchEncryptCipherState(b *testing.B, cs CipherState) {
-	plaintext := make([]byte, 1280)
-	ad := make([]byte, 16)
-	nb := make([]byte, 12)
-	out := make([]byte, 0, len(plaintext)+cs.Overhead())
-	b.ResetTimer()
-	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
-		var err error
-		out, err = cs.EncryptDanger(out[:0], ad, plaintext, uint64(i+1), nb)
-		if err != nil {
-			b.Fatal(err)
-		}
-	}
-}
-
-func buildCipherStatesB(b *testing.B, c noise.CipherFunc) (*noise.CipherState, *noise.CipherState) {
-	b.Helper()
-	suite := noise.NewCipherSuite(noise.DH25519, c, noise.HashSHA256)
-	cfg := noise.Config{CipherSuite: suite, Pattern: noise.HandshakeNN}
-	cfg.Initiator = true
-	hsI, err := noise.NewHandshakeState(cfg)
-	if err != nil {
-		b.Fatal(err)
-	}
-	cfg.Initiator = false
-	hsR, err := noise.NewHandshakeState(cfg)
-	if err != nil {
-		b.Fatal(err)
-	}
-	msg, _, _, err := hsI.WriteMessage(nil, nil)
-	if err != nil {
-		b.Fatal(err)
-	}
-	if _, _, _, err := hsR.ReadMessage(nil, msg); err != nil {
-		b.Fatal(err)
-	}
-	msg, dR, _, err := hsR.WriteMessage(nil, nil)
-	if err != nil {
-		b.Fatal(err)
-	}
-	_, eI, _, err := hsI.ReadMessage(nil, msg)
-	if err != nil {
-		b.Fatal(err)
-	}
-	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))
-	require.Error(t, err)
-	out, err := aes.DecryptDanger(nil, nil, nil, 0, make([]byte, 12))
-	require.NoError(t, err)
-	assert.Empty(t, out)
-	assert.Equal(t, 0, aes.Overhead())
-
-	var cc *CipherStateChaChaPoly
-	_, err = cc.EncryptDanger(nil, nil, nil, 0, make([]byte, 12))
-	require.Error(t, err)
-	out, err = cc.DecryptDanger(nil, nil, nil, 0, make([]byte, 12))
-	require.NoError(t, err)
-	assert.Empty(t, out)
-	assert.Equal(t, 0, cc.Overhead())
-}

outside.go

@@ -20,46 +20,24 @@ const (
 	minFwPacketLen = 4
 )
 
-var ErrOutOfWindow = errors.New("out of window packet")
-
-func (f *Interface) readOutsidePackets(via ViaSender, packet []byte, h *header.H, fwPacket *firewall.Packet, lhf *LightHouseHandler, nb []byte, q int, localCache firewall.ConntrackCache) {
+func (f *Interface) readOutsidePackets(via ViaSender, buf *WireBuffer, packet []byte, lhf *LightHouseHandler, q int, localCache firewall.ConntrackCache) {
+	h := buf.H
 	err := h.Parse(packet)
 	if err != nil {
 		// Hole punch packets are 0 or 1 byte big, so lets ignore printing those errors
-		// TODO: record metrics for rx holepunch/punchy packets?
 		if len(packet) > 1 {
-			f.messageMetrics.RxInvalid(1)
-			if f.l.Enabled(context.Background(), slog.LevelDebug) {
-				f.l.Debug("Error while parsing inbound packet",
-					"from", via,
-					"error", err,
-					"packet", packet,
-				)
-			}
-		}
-		return
-	}
-
-	if h.Version != header.Version {
-		f.messageMetrics.RxInvalid(1)
-		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			f.l.Debug("Unexpected header version received", "from", via)
-		}
-		return
-	}
-
-	// Check before processing to see if this is a expected type/subtype
-	if !h.IsValidSubType() {
-		f.messageMetrics.RxInvalid(1)
-		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			f.l.Debug("Unexpected packet received", "from", via)
+			f.l.Info("Error while parsing inbound packet",
+				"from", via,
+				"error", err,
+				"packet", packet,
+			)
 		}
 		return
 	}
 
+	//l.Error("in packet ", header, packet[HeaderLen:])
 	if !via.IsRelayed {
 		if f.myVpnNetworksTable.Contains(via.UdpAddr.Addr()) {
-			f.messageMetrics.RxInvalid(1)
 			if f.l.Enabled(context.Background(), slog.LevelDebug) {
 				f.l.Debug("Refusing to process double encrypted packet", "from", via)
 			}
@@ -67,194 +45,217 @@ func (f *Interface) readOutsidePackets(via ViaSender, packet []byte, h *header.H
 		}
 	}
 
-	// don't keep Rx metrics for message type, since you can see those in the tun metrics
-	if h.Type != header.Message {
-		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
-	}
-
-	// Unencrypted packets
-	switch h.Type {
-	case header.Handshake:
-		f.handshakeManager.HandleIncoming(via, packet, h)
-		return
-
-	case header.RecvError:
-		f.handleRecvError(via.UdpAddr, h)
-		return
-	}
-
-	// Relay packets are special
-	isMessageRelay := (h.Type == header.Message && h.Subtype == header.MessageRelay)
-
 	var hostinfo *HostInfo
-	if isMessageRelay {
+	// verify if we've seen this index before, otherwise respond to the handshake initiation
+	if h.Type == header.Message && h.Subtype == header.MessageRelay {
 		hostinfo = f.hostMap.QueryRelayIndex(h.RemoteIndex)
 	} else {
 		hostinfo = f.hostMap.QueryIndex(h.RemoteIndex)
 	}
 
-	// At this point we should have a valid existing tunnel, verify and send
-	// recvError if necessary
-	if hostinfo == nil || hostinfo.ConnectionState == nil {
-		if !via.IsRelayed {
-			f.maybeSendRecvError(via.UdpAddr, h.RemoteIndex)
-		}
-		return
+	var ci *ConnectionState
+	if hostinfo != nil {
+		ci = hostinfo.ConnectionState
 	}
 
-	// All remaining packets are encrypted
-	ci := hostinfo.ConnectionState
-	if !ci.window.Check(f.l, h.MessageCounter) {
-		return
-	}
-
-	// Relay packets are special
-	if isMessageRelay {
-		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) {
-			hostinfo.logger(f.l).Debug("Failed to decrypt packet",
-				"error", err,
-				"from", via,
-				"header", h,
-			)
-		}
-		return
-	}
-
-	// Roam before we respond
-	f.handleHostRoaming(hostinfo, via)
-	f.connectionManager.In(hostinfo)
-
 	switch h.Type {
 	case header.Message:
+		if !f.handleEncrypted(ci, via, h) {
+			return
+		}
+
 		switch h.Subtype {
 		case header.MessageNone:
-			f.handleOutsideMessagePacket(hostinfo, out, packet, fwPacket, nb, q, localCache)
-		default:
-			hostinfo.logger(f.l).Error("IsValidSubType was true, but unexpected message subtype seen", "from", via, "header", h)
-			return
+			if !f.decryptToTun(hostinfo, h.MessageCounter, buf, packet, q, localCache) {
+				return
+			}
+		case header.MessageRelay:
+			// 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
+			// otherwise malformed (meaning, there is no trailing 16 byte AEAD value), then this will result in at worst a 0-length slice
+			// which will gracefully fail in the DecryptDanger call.
+			signedPayload := packet[:len(packet)-hostinfo.ConnectionState.dKey.Overhead()]
+			signatureValue := packet[len(packet)-hostinfo.ConnectionState.dKey.Overhead():]
+			// AAD-only validation: passing dst=nil since there's no plaintext
+			// to recover (ciphertext is just the trailing AEAD tag).
+			if _, err = hostinfo.ConnectionState.dKey.DecryptDanger(nil, signedPayload, signatureValue, h.MessageCounter, buf.NB); err != nil {
+				return
+			}
+			// Successfully validated the thing. Get rid of the Relay header.
+			signedPayload = signedPayload[header.Len:]
+			// Pull the Roaming parts up here, and return in all call paths.
+			f.handleHostRoaming(hostinfo, via)
+			// Track usage of both the HostInfo and the Relay for the received & authenticated packet
+			f.connectionManager.In(hostinfo)
+			f.connectionManager.RelayUsed(h.RemoteIndex)
+
+			relay, ok := hostinfo.relayState.QueryRelayForByIdx(h.RemoteIndex)
+			if !ok {
+				// 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",
+					"vpnAddrs", hostinfo.vpnAddrs,
+					"remoteIndex", h.RemoteIndex,
+				)
+				return
+			}
+
+			switch relay.Type {
+			case TerminalType:
+				// If I am the target of this relay, process the unwrapped packet
+				// From this recursive point, all these variables are 'burned'. We shouldn't rely on them again.
+				via = ViaSender{
+					UdpAddr:   via.UdpAddr,
+					relayHI:   hostinfo,
+					remoteIdx: relay.RemoteIndex,
+					relay:     relay,
+					IsRelayed: true,
+				}
+				buf.Reset()
+				f.readOutsidePackets(via, buf, signedPayload, lhf, q, localCache)
+				return
+			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,
+						"error", err,
+						"hostinfo.vpnAddrs", hostinfo.vpnAddrs,
+					)
+					return
+				}
+
+				// If that relay is Established, forward the payload through it
+				if targetRelay.State == Established {
+					switch targetRelay.Type {
+					case ForwardingType:
+						// Forward this packet through the relay tunnel
+						// Find the target HostInfo
+						f.SendVia(targetHI, targetRelay, signedPayload, buf)
+						return
+					case TerminalType:
+						hostinfo.logger(f.l).Error("Unexpected Relay Type of Terminal")
+					}
+				} else {
+					hostinfo.logger(f.l).Info("Unexpected target relay state",
+						"relayTo", relay.PeerAddr,
+						"relayFrom", hostinfo.vpnAddrs[0],
+						"targetRelayState", targetRelay.State,
+					)
+					return
+				}
+			}
 		}
 
 	case header.LightHouse:
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
+		if !f.handleEncrypted(ci, via, h) {
+			return
+		}
+
+		d, err := f.decrypt(hostinfo, h.MessageCounter, buf, packet, h)
+		if err != nil {
+			hostinfo.logger(f.l).Error("Failed to decrypt lighthouse packet",
+				"error", err,
+				"from", via,
+				"packet", packet,
+			)
+			return
+		}
+
 		//TODO: assert via is not relayed
-		lhf.HandleRequest(via.UdpAddr, hostinfo.vpnAddrs, out, f)
+		lhf.HandleRequest(via.UdpAddr, hostinfo.vpnAddrs, d, f)
+
+		// Fallthrough to the bottom to record incoming traffic
 
 	case header.Test:
-		switch h.Subtype {
-		case header.TestReply:
-			// No-op, useful for the Roaming and connectionManager side-effects above
-		case header.TestRequest:
-			f.send(header.Test, header.TestReply, ci, hostinfo, out, nb, out)
-		default:
-			hostinfo.logger(f.l).Error("IsValidSubType was true, but unexpected test subtype seen", "from", via, "header", h)
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
+		if !f.handleEncrypted(ci, via, h) {
 			return
 		}
 
+		d, err := f.decrypt(hostinfo, h.MessageCounter, buf, packet, h)
+		if err != nil {
+			hostinfo.logger(f.l).Error("Failed to decrypt test packet",
+				"error", err,
+				"from", via,
+				"packet", packet,
+			)
+			return
+		}
+
+		if h.Subtype == header.TestRequest {
+			// This testRequest might be from TryPromoteBest, so we should roam
+			// to the new IP address before responding.
+			f.handleHostRoaming(hostinfo, via)
+			f.send(header.Test, header.TestReply, ci, hostinfo, d, buf)
+		}
+
+		// Fallthrough to the bottom to record incoming traffic
+
+		// Non encrypted messages below here, they should not fall through to avoid tracking incoming traffic since they
+		// are unauthenticated
+
+	case header.Handshake:
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
+		f.handshakeManager.HandleIncoming(via, packet, h)
+		return
+
+	case header.RecvError:
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
+		f.handleRecvError(via.UdpAddr, h)
+		return
+
 	case header.CloseTunnel:
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
+		if !f.handleEncrypted(ci, via, h) {
+			return
+		}
+		_, err = f.decrypt(hostinfo, h.MessageCounter, buf, packet, h)
+		if err != nil {
+			hostinfo.logger(f.l).Error("Failed to decrypt CloseTunnel packet",
+				"error", err,
+				"from", via,
+				"packet", packet,
+			)
+			return
+		}
+
 		hostinfo.logger(f.l).Info("Close tunnel received, tearing down.", "from", via)
+
 		f.closeTunnel(hostinfo)
+		return
 
 	case header.Control:
-		f.relayManager.HandleControlMsg(hostinfo, out, f)
-
-	default:
-		hostinfo.logger(f.l).Error("IsValidSubType was true, but unexpected message type seen", "from", via, "header", h)
-	}
-}
-
-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
-	// otherwise malformed (meaning, there is no trailing 16 byte AEAD value), then this will result in at worst a 0-length slice
-	// which will gracefully fail in the DecryptDanger call.
-	signedPayload := packet[:len(packet)-hostinfo.ConnectionState.dKey.Overhead()]
-	signatureValue := packet[len(packet)-hostinfo.ConnectionState.dKey.Overhead():]
-	// 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.
-	signedPayload = signedPayload[header.Len:]
-	// Pull the Roaming parts up here, and return in all call paths.
-	f.handleHostRoaming(hostinfo, via)
-	// Track usage of both the HostInfo and the Relay for the received & authenticated packet
-	f.connectionManager.In(hostinfo)
-	f.connectionManager.RelayUsed(h.RemoteIndex)
-
-	relay, ok := hostinfo.relayState.QueryRelayForByIdx(h.RemoteIndex)
-	if !ok {
-		// 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",
-			"vpnAddrs", hostinfo.vpnAddrs,
-			"remoteIndex", h.RemoteIndex,
-		)
-		return
-	}
-
-	switch relay.Type {
-	case TerminalType:
-		// If I am the target of this relay, process the unwrapped packet
-		// From this recursive point, all these variables are 'burned'. We shouldn't rely on them again.
-		via = ViaSender{
-			UdpAddr:   via.UdpAddr,
-			relayHI:   hostinfo,
-			remoteIdx: relay.RemoteIndex,
-			relay:     relay,
-			IsRelayed: true,
+		if !f.handleEncrypted(ci, via, h) {
+			return
 		}
-		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)
+
+		d, err := f.decrypt(hostinfo, h.MessageCounter, buf, packet, h)
 		if err != nil {
-			hostinfo.logger(f.l).Info("Failed to find target host info by ip",
-				"relayTo", relay.PeerAddr,
+			hostinfo.logger(f.l).Error("Failed to decrypt Control packet",
 				"error", err,
-				"hostinfo.vpnAddrs", hostinfo.vpnAddrs,
+				"from", via,
+				"packet", packet,
 			)
 			return
 		}
 
-		// If that relay is Established, forward the payload through it
-		if targetRelay.State == Established {
-			switch targetRelay.Type {
-			case ForwardingType:
-				// Forward this packet through the relay tunnel
-				// 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")
-				return
-			default:
-				if f.l.Enabled(context.Background(), slog.LevelDebug) {
-					hostinfo.logger(f.l).Debug("Unexpected targetRelay Type", "from", via, "relayType", targetRelay.Type)
-				}
-				return
-			}
-		} else {
-			hostinfo.logger(f.l).Info("Unexpected target relay state",
-				"relayTo", relay.PeerAddr,
-				"relayFrom", hostinfo.vpnAddrs[0],
-				"targetRelayState", targetRelay.State,
-			)
-			return
-		}
+		f.relayManager.HandleControlMsg(hostinfo, d, f)
+
 	default:
+		f.messageMetrics.Rx(h.Type, h.Subtype, 1)
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
-			hostinfo.logger(f.l).Debug("Unexpected relay type", "from", via, "relayType", relay.Type)
+			hostinfo.logger(f.l).Debug("Unexpected packet received", "from", via)
 		}
+		return
 	}
+
+	f.handleHostRoaming(hostinfo, via)
+
+	f.connectionManager.In(hostinfo)
 }
 
 // closeTunnel closes a tunnel locally, it does not send a closeTunnel packet to the remote
@@ -268,7 +269,9 @@ func (f *Interface) closeTunnel(hostInfo *HostInfo) {
 
 // sendCloseTunnel is a helper function to send a proper close tunnel packet to a remote
 func (f *Interface) sendCloseTunnel(h *HostInfo) {
-	f.send(header.CloseTunnel, 0, h.ConnectionState, h, []byte{}, make([]byte, 12, 12), make([]byte, mtu))
+	buf := f.bufAlloc.Acquire()
+	defer f.bufAlloc.Release(buf)
+	f.send(header.CloseTunnel, 0, h.ConnectionState, h, []byte{}, buf)
 }
 
 func (f *Interface) handleHostRoaming(hostinfo *HostInfo, via ViaSender) {
@@ -302,6 +305,23 @@ func (f *Interface) handleHostRoaming(hostinfo *HostInfo, via ViaSender) {
 
 }
 
+// handleEncrypted returns true if a packet should be processed, false otherwise
+func (f *Interface) handleEncrypted(ci *ConnectionState, via ViaSender, h *header.H) bool {
+	// If connectionstate does not exist, send a recv error, if possible, to encourage a fast reconnect
+	if ci == nil {
+		if !via.IsRelayed {
+			f.maybeSendRecvError(via.UdpAddr, h.RemoteIndex)
+		}
+		return false
+	}
+	// If the window check fails, refuse to process the packet, but don't send a recv error
+	if !ci.window.Check(f.l, h.MessageCounter) {
+		return false
+	}
+
+	return true
+}
+
 var (
 	ErrPacketTooShort          = errors.New("packet is too short")
 	ErrUnknownIPVersion        = errors.New("packet is an unknown ip version")
@@ -500,48 +520,65 @@ func parseV4(data []byte, incoming bool, fp *firewall.Packet) error {
 	return nil
 }
 
-func (f *Interface) decrypt(hostinfo *HostInfo, mc uint64, out []byte, packet []byte, h *header.H, nb []byte) ([]byte, error) {
-	var err error
-	out, err = hostinfo.ConnectionState.dKey.DecryptDanger(out, packet[:header.Len], packet[header.Len:], mc, nb)
+func (f *Interface) decrypt(hostinfo *HostInfo, mc uint64, buf *WireBuffer, packet []byte, h *header.H) ([]byte, error) {
+	plaintext, err := buf.DecryptForHandler(hostinfo.ConnectionState, packet, mc)
 	if err != nil {
 		return nil, err
 	}
 
 	if !hostinfo.ConnectionState.window.Update(f.l, mc) {
-		return nil, ErrOutOfWindow
+		if f.l.Enabled(context.Background(), slog.LevelDebug) {
+			hostinfo.logger(f.l).Debug("dropping out of window packet", "header", h)
+		}
+		return nil, errors.New("out of window packet")
 	}
 
-	return out, nil
+	return plaintext, nil
 }
 
-func (f *Interface) handleOutsideMessagePacket(hostinfo *HostInfo, out []byte, packet []byte, fwPacket *firewall.Packet, nb []byte, q int, localCache firewall.ConntrackCache) {
-	err := newPacket(out, true, fwPacket)
-	if err != nil {
-		hostinfo.logger(f.l).Warn("Error while validating inbound packet",
-			"error", err,
-			"packet", out,
-		)
-		return
+func (f *Interface) decryptToTun(hostinfo *HostInfo, messageCounter uint64, buf *WireBuffer, packet []byte, q int, localCache firewall.ConntrackCache) bool {
+	if err := buf.DecryptDatagram(hostinfo.ConnectionState, packet, messageCounter); err != nil {
+		hostinfo.logger(f.l).Error("Failed to decrypt packet", "error", err)
+		return false
 	}
 
-	dropReason := f.firewall.Drop(*fwPacket, true, hostinfo, f.pki.GetCAPool(), localCache)
+	ipPacket := buf.IPPacket()
+	if err := newPacket(ipPacket, true, buf.FwPacket); err != nil {
+		hostinfo.logger(f.l).Warn("Error while validating inbound packet",
+			"error", err,
+			"packet", ipPacket,
+		)
+		return false
+	}
+
+	if !hostinfo.ConnectionState.window.Update(f.l, messageCounter) {
+		if f.l.Enabled(context.Background(), slog.LevelDebug) {
+			hostinfo.logger(f.l).Debug("dropping out of window packet", "fwPacket", buf.FwPacket)
+		}
+		return false
+	}
+
+	dropReason := f.firewall.Drop(*buf.FwPacket, true, hostinfo, f.pki.GetCAPool(), localCache)
 	if dropReason != nil {
-		// NOTE: We give `packet` as the `out` here since we already decrypted from it and we don't need it anymore
-		// This gives us a buffer to build the reject packet in
-		f.rejectOutside(out, hostinfo.ConnectionState, hostinfo, nb, packet, q)
+		// NOTE: We hand `packet` (the original UDP ciphertext we already
+		// decrypted from) as the reject-IP scratch since we no longer
+		// need its ciphertext, and it's disjoint from buf.Out where
+		// sendNoMetrics will encrypt the wire packet.
+		f.rejectOutside(ipPacket, hostinfo.ConnectionState, hostinfo, packet, buf, q)
 		if f.l.Enabled(context.Background(), slog.LevelDebug) {
 			hostinfo.logger(f.l).Debug("dropping inbound packet",
-				"fwPacket", fwPacket,
+				"fwPacket", buf.FwPacket,
 				"reason", dropReason,
 			)
 		}
-		return
+		return false
 	}
 
-	err = f.batchers[q].Commit(out)
-	if err != nil {
+	f.connectionManager.In(hostinfo)
+	if _, err := buf.WriteIPToTUN(f.readers[q]); err != nil {
 		f.l.Error("Failed to write to tun", "error", err)
 	}
+	return true
 }
 
 func (f *Interface) maybeSendRecvError(endpoint netip.AddrPort, index uint32) {

overlay/batch/coalesce_core.go

@@ -1,42 +0,0 @@
-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

@@ -1,46 +0,0 @@
-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

@@ -1,12 +0,0 @@
-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

@@ -1,60 +0,0 @@
-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

@@ -1,126 +0,0 @@
-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

@@ -4,21 +4,18 @@ 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.Closer
+	io.ReadWriteCloser
 	Activate() error
 	Networks() []netip.Prefix
 	Name() string
 	RoutesFor(netip.Addr) routing.Gateways
 	SupportsMultiqueue() bool
-	NewMultiQueueReader() error
-	Readers() []tio.Queue
+	NewMultiQueueReader() (io.ReadWriteCloser, error)
+	// TunPrefixLen reports the number of bytes the device prepends to every IP packet on the wire.
+	// Currently only non zero for the BSD tun devices.
+	TunPrefixLen() int
 }

overlay/network_category_windows.go

@@ -1,358 +0,0 @@
-//go:build !e2e_testing
-// +build !e2e_testing
-
-package overlay
-
-import (
-	"errors"
-	"fmt"
-	"log/slog"
-	"runtime"
-	"strings"
-	"syscall"
-	"time"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-// networkCategory mirrors NLM_NETWORK_CATEGORY from netlistmgr.h.
-type networkCategory int32
-
-const (
-	networkCategoryPublic              networkCategory = 0
-	networkCategoryPrivate             networkCategory = 1
-	networkCategoryDomainAuthenticated networkCategory = 2
-)
-
-func (c networkCategory) String() string {
-	switch c {
-	case networkCategoryPublic:
-		return "public"
-	case networkCategoryPrivate:
-		return "private"
-	case networkCategoryDomainAuthenticated:
-		return "domain"
-	}
-	return fmt.Sprintf("unknown(%d)", c)
-}
-
-// parseNetworkCategory accepts the user-supplied tun.network_category. A
-// second return of false means "leave the category alone".
-func parseNetworkCategory(s string) (networkCategory, bool, error) {
-	switch strings.ToLower(strings.TrimSpace(s)) {
-	case "", "unset":
-		return 0, false, nil
-	case "public":
-		return networkCategoryPublic, true, nil
-	case "private":
-		return networkCategoryPrivate, true, nil
-	case "domain", "domainauthenticated":
-		return networkCategoryDomainAuthenticated, true, nil
-	}
-	return 0, false, fmt.Errorf("unknown tun.network_category %q (expected public, private, domain, or unset)", s)
-}
-
-// CLSID_NetworkListManager {DCB00C01-570F-4A9B-8D69-199FDBA5723B}
-var clsidNetworkListManager = windows.GUID{
-	Data1: 0xDCB00C01, Data2: 0x570F, Data3: 0x4A9B,
-	Data4: [8]byte{0x8D, 0x69, 0x19, 0x9F, 0xDB, 0xA5, 0x72, 0x3B},
-}
-
-// IID_INetworkListManager {DCB00000-570F-4A9B-8D69-199FDBA5723B}
-var iidINetworkListManager = windows.GUID{
-	Data1: 0xDCB00000, Data2: 0x570F, Data3: 0x4A9B,
-	Data4: [8]byte{0x8D, 0x69, 0x19, 0x9F, 0xDB, 0xA5, 0x72, 0x3B},
-}
-
-// x/sys/windows doesn't expose CoCreateInstance, so we bind it ourselves.
-var procCoCreateInstance = windows.NewLazySystemDLL("ole32.dll").NewProc("CoCreateInstance")
-
-const clsCtxAll = windows.CLSCTX_INPROC_SERVER | windows.CLSCTX_INPROC_HANDLER |
-	windows.CLSCTX_LOCAL_SERVER | windows.CLSCTX_REMOTE_SERVER
-
-const (
-	hrSFALSE          = 0x00000001
-	hrRPCEChangedMode = 0x80010106
-)
-
-type hresult uint32
-
-func (h hresult) failed() bool { return int32(h) < 0 }
-func (h hresult) String() string {
-	return fmt.Sprintf("HRESULT 0x%08x", uint32(h))
-}
-
-var errAdapterNotFound = errors.New("adapter not present in network connections enumeration")
-
-// Vtable layouts. Slot order must match the declaration order in netlistmgr.h.
-// All NLM interfaces here derive from IDispatch, which derives from IUnknown.
-
-type iUnknownVtbl struct {
-	QueryInterface uintptr
-	AddRef         uintptr
-	Release        uintptr
-}
-
-type iDispatchVtbl struct {
-	iUnknownVtbl
-	GetTypeInfoCount uintptr
-	GetTypeInfo      uintptr
-	GetIDsOfNames    uintptr
-	Invoke           uintptr
-}
-
-type iNetworkListManagerVtbl struct {
-	iDispatchVtbl
-	GetNetworks           uintptr
-	GetNetwork            uintptr
-	GetNetworkConnections uintptr
-	GetNetworkConnection  uintptr
-	IsConnectedToInternet uintptr
-	IsConnected           uintptr
-	GetConnectivity       uintptr
-}
-
-type iNetworkListManager struct{ Vtbl *iNetworkListManagerVtbl }
-
-func (n *iNetworkListManager) Release() {
-	syscall.SyscallN(n.Vtbl.Release, uintptr(unsafe.Pointer(n)))
-}
-
-func (n *iNetworkListManager) GetNetworkConnections() (*iEnumNetworkConnections, error) {
-	var enum *iEnumNetworkConnections
-	r1, _, _ := syscall.SyscallN(n.Vtbl.GetNetworkConnections,
-		uintptr(unsafe.Pointer(n)), uintptr(unsafe.Pointer(&enum)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return nil, fmt.Errorf("INetworkListManager.GetNetworkConnections: %s", hr)
-	}
-	return enum, nil
-}
-
-type iEnumNetworkConnectionsVtbl struct {
-	iDispatchVtbl
-	NewEnum uintptr
-	Next    uintptr
-	Skip    uintptr
-	Reset   uintptr
-	Clone   uintptr
-}
-
-type iEnumNetworkConnections struct{ Vtbl *iEnumNetworkConnectionsVtbl }
-
-func (e *iEnumNetworkConnections) Release() {
-	syscall.SyscallN(e.Vtbl.Release, uintptr(unsafe.Pointer(e)))
-}
-
-// Next returns the next connection, or (nil, nil) at the end of the enumeration.
-func (e *iEnumNetworkConnections) Next() (*iNetworkConnection, error) {
-	var conn *iNetworkConnection
-	var fetched uint32
-	r1, _, _ := syscall.SyscallN(e.Vtbl.Next,
-		uintptr(unsafe.Pointer(e)), 1,
-		uintptr(unsafe.Pointer(&conn)), uintptr(unsafe.Pointer(&fetched)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return nil, fmt.Errorf("IEnumNetworkConnections.Next: %s", hr)
-	}
-	if fetched == 0 {
-		return nil, nil
-	}
-	return conn, nil
-}
-
-type iNetworkConnectionVtbl struct {
-	iDispatchVtbl
-	GetNetwork            uintptr
-	IsConnectedToInternet uintptr
-	IsConnected           uintptr
-	GetConnectivity       uintptr
-	GetConnectionId       uintptr
-	GetAdapterId          uintptr
-	GetDomainType         uintptr
-}
-
-type iNetworkConnection struct{ Vtbl *iNetworkConnectionVtbl }
-
-func (c *iNetworkConnection) Release() {
-	syscall.SyscallN(c.Vtbl.Release, uintptr(unsafe.Pointer(c)))
-}
-
-func (c *iNetworkConnection) GetAdapterId() (windows.GUID, error) {
-	var g windows.GUID
-	r1, _, _ := syscall.SyscallN(c.Vtbl.GetAdapterId,
-		uintptr(unsafe.Pointer(c)), uintptr(unsafe.Pointer(&g)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return windows.GUID{}, fmt.Errorf("INetworkConnection.GetAdapterId: %s", hr)
-	}
-	return g, nil
-}
-
-func (c *iNetworkConnection) GetNetwork() (*iNetwork, error) {
-	var net *iNetwork
-	r1, _, _ := syscall.SyscallN(c.Vtbl.GetNetwork,
-		uintptr(unsafe.Pointer(c)), uintptr(unsafe.Pointer(&net)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return nil, fmt.Errorf("INetworkConnection.GetNetwork: %s", hr)
-	}
-	return net, nil
-}
-
-type iNetworkVtbl struct {
-	iDispatchVtbl
-	GetName                    uintptr
-	SetName                    uintptr
-	GetDescription             uintptr
-	SetDescription             uintptr
-	GetNetworkId               uintptr
-	GetDomainType              uintptr
-	GetNetworkConnections      uintptr
-	GetTimeCreatedAndConnected uintptr
-	IsConnectedToInternet      uintptr
-	IsConnected                uintptr
-	GetConnectivity            uintptr
-	GetCategory                uintptr
-	SetCategory                uintptr
-}
-
-type iNetwork struct{ Vtbl *iNetworkVtbl }
-
-func (n *iNetwork) Release() {
-	syscall.SyscallN(n.Vtbl.Release, uintptr(unsafe.Pointer(n)))
-}
-
-func (n *iNetwork) GetCategory() (networkCategory, error) {
-	var c networkCategory
-	r1, _, _ := syscall.SyscallN(n.Vtbl.GetCategory,
-		uintptr(unsafe.Pointer(n)), uintptr(unsafe.Pointer(&c)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return 0, fmt.Errorf("INetwork.GetCategory: %s", hr)
-	}
-	return c, nil
-}
-
-func (n *iNetwork) SetCategory(c networkCategory) error {
-	r1, _, _ := syscall.SyscallN(n.Vtbl.SetCategory,
-		uintptr(unsafe.Pointer(n)), uintptr(int32(c)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return fmt.Errorf("INetwork.SetCategory: %s", hr)
-	}
-	return nil
-}
-
-// coInit initializes COM for the current OS thread. The returned function must
-// be deferred to balance a successful init. RPC_E_CHANGED_MODE means COM is
-// already initialized in a different mode on this thread, which is still fine
-// for our calls but we must not Uninitialize in that case.
-func coInit() (func(), error) {
-	err := windows.CoInitializeEx(0, windows.COINIT_MULTITHREADED)
-	if err == nil {
-		return windows.CoUninitialize, nil
-	}
-	if e, ok := err.(syscall.Errno); ok {
-		switch uint32(e) {
-		case hrSFALSE:
-			return windows.CoUninitialize, nil
-		case hrRPCEChangedMode:
-			return func() {}, nil
-		}
-	}
-	return nil, fmt.Errorf("CoInitializeEx: %w", err)
-}
-
-func createNetworkListManager() (*iNetworkListManager, error) {
-	var nlm *iNetworkListManager
-	r1, _, _ := procCoCreateInstance.Call(
-		uintptr(unsafe.Pointer(&clsidNetworkListManager)),
-		0,
-		uintptr(clsCtxAll),
-		uintptr(unsafe.Pointer(&iidINetworkListManager)),
-		uintptr(unsafe.Pointer(&nlm)),
-	)
-	if hr := hresult(r1); hr.failed() {
-		return nil, fmt.Errorf("CoCreateInstance(NetworkListManager): %s", hr)
-	}
-	return nlm, nil
-}
-
-// setNetworkCategory locates the network connection bound to adapterGUID and
-// sets the category of its parent network. Returns errAdapterNotFound if the
-// adapter is not yet visible in the NLM enumeration.
-func setNetworkCategory(adapterGUID windows.GUID, cat networkCategory) error {
-	deinit, err := coInit()
-	if err != nil {
-		return err
-	}
-	defer deinit()
-
-	nlm, err := createNetworkListManager()
-	if err != nil {
-		return err
-	}
-	defer nlm.Release()
-
-	enum, err := nlm.GetNetworkConnections()
-	if err != nil {
-		return err
-	}
-	defer enum.Release()
-
-	for {
-		conn, err := enum.Next()
-		if err != nil {
-			return err
-		}
-		if conn == nil {
-			return errAdapterNotFound
-		}
-
-		guid, err := conn.GetAdapterId()
-		if err != nil || guid != adapterGUID {
-			conn.Release()
-			continue
-		}
-
-		net, err := conn.GetNetwork()
-		conn.Release()
-		if err != nil {
-			return err
-		}
-		err = net.SetCategory(cat)
-		net.Release()
-		return err
-	}
-}
-
-// applyNetworkCategory polls until the wintun adapter shows up in the NLM
-// enumeration, then sets the category. Intended to run in its own goroutine.
-func applyNetworkCategory(l *slog.Logger, adapterGUID windows.GUID, cat networkCategory) {
-	// COM Init/Uninit must be paired on the same OS thread.
-	runtime.LockOSThread()
-	defer runtime.UnlockOSThread()
-
-	const (
-		attempts = 30
-		interval = 500 * time.Millisecond
-	)
-	for i := 0; i < attempts; i++ {
-		err := setNetworkCategory(adapterGUID, cat)
-		if err == nil {
-			l.Info("Set Windows network category", "category", cat.String())
-			return
-		}
-		if !errors.Is(err, errAdapterNotFound) {
-			l.Warn("Failed to set Windows network category", "error", err, "category", cat.String())
-			return
-		}
-		time.Sleep(interval)
-	}
-	l.Warn("Gave up waiting for adapter to appear in NLM enumeration; network category not set",
-		"category", cat.String(),
-		"waited", time.Duration(attempts)*interval,
-	)
-}

overlay/network_category_windows_test.go

@@ -1,109 +0,0 @@
-//go:build !e2e_testing
-// +build !e2e_testing
-
-package overlay
-
-import (
-	"testing"
-)
-
-func Test_parseNetworkCategory(t *testing.T) {
-	cases := []struct {
-		in        string
-		wantCat   networkCategory
-		wantApply bool
-		wantErr   bool
-	}{
-		{"", 0, false, false},
-		{"unset", 0, false, false},
-		{"  UNSET  ", 0, false, false},
-		{"private", networkCategoryPrivate, true, false},
-		{"Private", networkCategoryPrivate, true, false},
-		{"  PRIVATE  ", networkCategoryPrivate, true, false},
-		{"public", networkCategoryPublic, true, false},
-		{"PUBLIC", networkCategoryPublic, true, false},
-		{"domain", networkCategoryDomainAuthenticated, true, false},
-		{"DomainAuthenticated", networkCategoryDomainAuthenticated, true, false},
-		{"garbage", 0, false, true},
-		{"privates", 0, false, true},
-	}
-	for _, tc := range cases {
-		cat, apply, err := parseNetworkCategory(tc.in)
-		if (err != nil) != tc.wantErr {
-			t.Errorf("parseNetworkCategory(%q) err=%v, wantErr=%v", tc.in, err, tc.wantErr)
-			continue
-		}
-		if cat != tc.wantCat || apply != tc.wantApply {
-			t.Errorf("parseNetworkCategory(%q) = (%v, %v), want (%v, %v)", tc.in, cat, apply, tc.wantCat, tc.wantApply)
-		}
-	}
-}
-
-// Test_NLM_round_trip exercises every COM call path used by setNetworkCategory
-// without mutating the host's network state. It validates the CLSID/IID
-// constants and every vtable index by enumerating connections, fetching the
-// adapter id and parent network, reading the current category, and writing it
-// back unchanged.
-//
-// Requires Windows but does not require admin or the wintun driver. Skips if
-// no network connections are available (unlikely outside of an isolated
-// container).
-func Test_NLM_round_trip(t *testing.T) {
-	deinit, err := coInit()
-	if err != nil {
-		t.Fatalf("coInit: %v", err)
-	}
-	defer deinit()
-
-	nlm, err := createNetworkListManager()
-	if err != nil {
-		t.Fatalf("createNetworkListManager: %v", err)
-	}
-	defer nlm.Release()
-
-	enum, err := nlm.GetNetworkConnections()
-	if err != nil {
-		t.Fatalf("GetNetworkConnections: %v", err)
-	}
-	defer enum.Release()
-
-	saw := 0
-	for {
-		conn, err := enum.Next()
-		if err != nil {
-			t.Fatalf("EnumNetworkConnections.Next: %v", err)
-		}
-		if conn == nil {
-			break
-		}
-		saw++
-
-		if _, err := conn.GetAdapterId(); err != nil {
-			conn.Release()
-			t.Fatalf("INetworkConnection.GetAdapterId: %v", err)
-		}
-
-		net, err := conn.GetNetwork()
-		conn.Release()
-		if err != nil {
-			t.Fatalf("INetworkConnection.GetNetwork: %v", err)
-		}
-
-		cat, err := net.GetCategory()
-		if err != nil {
-			net.Release()
-			t.Fatalf("INetwork.GetCategory: %v", err)
-		}
-		// Set to the current value so the host's NLM state is unchanged but
-		// SetCategory's vtable slot is still validated end-to-end.
-		if err := net.SetCategory(cat); err != nil {
-			net.Release()
-			t.Fatalf("INetwork.SetCategory(%v): %v", cat, err)
-		}
-		net.Release()
-	}
-
-	if saw == 0 {
-		t.Skip("no NLM network connections available; skipping round-trip")
-	}
-}

overlay/overlaytest/noop.go

@@ -4,11 +4,10 @@ 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.
@@ -16,10 +15,6 @@ 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{}
 }
@@ -36,7 +31,7 @@ func (NoopTun) Name() string {
 	return "noop"
 }
 
-func (NoopTun) Read(p []wire.TunPacket, mem []byte) (int, error) {
+func (NoopTun) Read([]byte) (int, error) {
 	return 0, nil
 }
 
@@ -48,14 +43,12 @@ func (NoopTun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (NoopTun) NewMultiQueueReader() error {
-	return errors.New("unsupported")
-}
-
-func (NoopTun) Readers() []tio.Queue {
-	return []tio.Queue{NoopTun{}}
+func (NoopTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, errors.New("unsupported")
 }
 
 func (NoopTun) Close() error {
 	return nil
 }
+
+func (NoopTun) TunPrefixLen() int { return 0 }

overlay/tio/queueset_poll_linux.go

@@ -1,80 +0,0 @@
-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

@@ -1,122 +0,0 @@
-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

@@ -1,168 +0,0 @@
-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

@@ -1,106 +0,0 @@
-//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

@@ -13,14 +13,12 @@ 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 {
-	rwc         io.ReadWriteCloser
+	io.ReadWriteCloser
 	fd          int
 	vpnNetworks []netip.Prefix
 	Routes      atomic.Pointer[[]Route]
@@ -28,37 +26,16 @@ 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{
-		rwc:         file,
-		fd:          deviceFd,
-		vpnNetworks: vpnNetworks,
-		l:           l,
+		ReadWriteCloser: file,
+		fd:              deviceFd,
+		vpnNetworks:     vpnNetworks,
+		l:               l,
 	}
 
 	err := t.reload(c, true)
@@ -85,7 +62,7 @@ func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
 	return r
 }
 
-func (t *tun) Activate() error {
+func (t tun) Activate() error {
 	return nil
 }
 
@@ -122,14 +99,8 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for android")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, 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{}
-}
+func (t *tun) TunPrefixLen() int { return 0 }

overlay/tun_bsd.go

@@ -0,0 +1,29 @@
+//go:build (darwin || ios || freebsd || openbsd || netbsd) && !e2e_testing
+
+package overlay
+
+import (
+	"fmt"
+	"syscall"
+)
+
+// StampTunPrefix writes the 4-byte AF_INET / AF_INET6 protocol-family marker into buf[0:4] in place,
+// picking the family from the first byte of the IP packet at buf[4].
+func StampTunPrefix(buf []byte) error {
+	if len(buf) < 5 {
+		return fmt.Errorf("tun write buffer too small for prefix")
+	}
+	ipVer := buf[4] >> 4
+	buf[0] = 0
+	buf[1] = 0
+	buf[2] = 0
+	switch ipVer {
+	case 4:
+		buf[3] = syscall.AF_INET
+	case 6:
+		buf[3] = syscall.AF_INET6
+	default:
+		return fmt.Errorf("unable to determine IP version from packet")
+	}
+	return nil
+}

overlay/tun_bypass_windows.go

@@ -1,23 +0,0 @@
-//go:build (amd64 || arm64) && !e2e_testing
-// +build amd64 arm64
-// +build !e2e_testing
-
-package overlay
-
-import (
-	"log/slog"
-
-	"github.com/slackhq/nebula/wfp"
-)
-
-// installInterfaceBypass installs a WFP PERMIT filter scoped to the wintun interface LUID so inbound traffic on the
-// nebula adapter bypasses Windows Defender Firewall.
-func installInterfaceBypass(l *slog.Logger, luid uint64) closer {
-	s, err := wfp.PermitInterface(luid)
-	if err != nil {
-		l.Warn("Failed to install WFP bypass filters on nebula interface", "error", err)
-		return nil
-	}
-	l.Info("Installed WFP filters bypassing Windows Defender Firewall on nebula interface")
-	return s
-}

overlay/tun_bypass_windows_386.go

@@ -1,11 +0,0 @@
-//go:build !e2e_testing
-// +build !e2e_testing
-
-package overlay
-
-import "log/slog"
-
-// installInterfaceBypass is a no-op on windows-386 because we don't currently build for it.
-func installInterfaceBypass(_ *slog.Logger, _ uint64) closer {
-	return nil
-}

overlay/tun_darwin.go

@@ -11,21 +11,18 @@ import (
 	"net/netip"
 	"os"
 	"sync/atomic"
-	"syscall"
 	"unsafe"
 
 	"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 {
-	rwc         io.ReadWriteCloser
+	io.ReadWriteCloser
 	Device      string
 	vpnNetworks []netip.Prefix
 	DefaultMTU  int
@@ -33,9 +30,6 @@ type tun struct {
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	linkAddr    *netroute.LinkAddr
 	l           *slog.Logger
-
-	// cache out buffer since we need to prepend 4 bytes for tun metadata
-	out []byte
 }
 
 type ifReq struct {
@@ -126,11 +120,11 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 	}
 
 	t := &tun{
-		rwc:         os.NewFile(uintptr(fd), ""),
-		Device:      name,
-		vpnNetworks: vpnNetworks,
-		DefaultMTU:  c.GetInt("tun.mtu", DefaultMTU),
-		l:           l,
+		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
+		Device:          name,
+		vpnNetworks:     vpnNetworks,
+		DefaultMTU:      c.GetInt("tun.mtu", DefaultMTU),
+		l:               l,
 	}
 
 	err = t.reload(c, true)
@@ -160,8 +154,8 @@ func newTunFromFd(_ *config.C, _ *slog.Logger, _ int, _ []netip.Prefix) (*tun, e
 }
 
 func (t *tun) Close() error {
-	if t.rwc != nil {
-		return t.rwc.Close()
+	if t.ReadWriteCloser != nil {
+		return t.ReadWriteCloser.Close()
 	}
 	return nil
 }
@@ -504,48 +498,6 @@ func delRoute(prefix netip.Prefix, gateway netroute.Addr) error {
 	return nil
 }
 
-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
-func (t *tun) Write(from []byte) (int, error) {
-	buf := t.out
-	if cap(buf) < len(from)+4 {
-		buf = make([]byte, len(from)+4)
-		t.out = buf
-	}
-	buf = buf[:len(from)+4]
-
-	if len(from) == 0 {
-		return 0, syscall.EIO
-	}
-
-	// Determine the IP Family for the NULL L2 Header
-	ipVer := from[0] >> 4
-	if ipVer == 4 {
-		buf[3] = syscall.AF_INET
-	} else if ipVer == 6 {
-		buf[3] = syscall.AF_INET6
-	} else {
-		return 0, fmt.Errorf("unable to determine IP version from packet")
-	}
-
-	copy(buf[4:], from)
-
-	n, err := t.rwc.Write(buf)
-	return n - 4, err
-}
-
 func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
@@ -558,14 +510,10 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for darwin")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, 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{}
-}
+// TunPrefixLen reports the 4-byte BSD AF_INET / AF_INET6 protocol-family
+// marker the kernel prepends on read and expects on write.
+func (t *tun) TunPrefixLen() int { return 4 }

overlay/tun_disabled.go

@@ -10,9 +10,7 @@ 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 {
@@ -20,10 +18,9 @@ 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
-	numReaders int
-	l          *slog.Logger
+	tx metrics.Counter
+	rx metrics.Counter
+	l  *slog.Logger
 }
 
 func newDisabledTun(vpnNetworks []netip.Prefix, queueLen int, metricsEnabled bool, l *slog.Logger) *disabledTun {
@@ -31,7 +28,6 @@ func newDisabledTun(vpnNetworks []netip.Prefix, queueLen int, metricsEnabled boo
 		vpnNetworks: vpnNetworks,
 		read:        make(chan []byte, queueLen),
 		l:           l,
-		numReaders:  1,
 	}
 
 	if metricsEnabled {
@@ -61,7 +57,7 @@ func (*disabledTun) Name() string {
 	return "disabled"
 }
 
-func (t *disabledTun) readOne(b []byte) (int, error) {
+func (t *disabledTun) Read(b []byte) (int, error) {
 	r, ok := <-t.read
 	if !ok {
 		return 0, io.EOF
@@ -79,19 +75,6 @@ func (t *disabledTun) readOne(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)
@@ -127,21 +110,8 @@ func (t *disabledTun) SupportsMultiqueue() bool {
 	return true
 }
 
-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) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return t, nil
 }
 
 func (t *disabledTun) Close() error {
@@ -166,3 +136,5 @@ func (p prettyPacket) String() string {
 
 	return s.String()
 }
+
+func (t *disabledTun) TunPrefixLen() int { return 0 }

overlay/tun_file_linux_test.go

@@ -0,0 +1,120 @@
+//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

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"io/fs"
 	"log/slog"
 	"net/netip"
@@ -17,10 +18,9 @@ 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"
@@ -157,88 +157,44 @@ func (t *tun) blockOnWrite() error {
 	return nil
 }
 
-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{
-		{&head[0], 4},
-		{&to[0], uint64(len(to))},
-	}
+func (t *tun) Read(to []byte) (int, error) {
 	for {
-		n, _, errno := syscall.Syscall(syscall.SYS_READV, uintptr(t.fd), uintptr(unsafe.Pointer(&iovecs[0])), 2)
-		if errno == 0 {
-			bytesRead := int(n)
-			if bytesRead < 4 {
-				return 0, nil
-			}
-			return bytesRead - 4, nil
+		n, err := unix.Read(t.fd, to)
+		if err == nil {
+			return n, nil
 		}
-		switch errno {
+		switch err {
 		case unix.EAGAIN:
-			if err := t.blockOnRead(); err != nil {
-				return 0, err
+			if berr := t.blockOnRead(); berr != nil {
+				return 0, berr
 			}
 		case unix.EINTR:
 			// retry
 		case unix.EBADF:
 			return 0, os.ErrClosed
 		default:
-			return 0, errno
+			return 0, err
 		}
 	}
 }
 
-// Write is only valid for single threaded use
 func (t *tun) Write(from []byte) (int, error) {
-	if len(from) <= 1 {
-		return 0, syscall.EIO
-	}
-
-	ipVer := from[0] >> 4
-	var head [4]byte
-	// first 4 bytes is protocol family, in network byte order
-	switch ipVer {
-	case 4:
-		head[3] = syscall.AF_INET
-	case 6:
-		head[3] = syscall.AF_INET6
-	default:
-		return 0, fmt.Errorf("unable to determine IP version from packet")
-	}
-
-	iovecs := [2]syscall.Iovec{
-		{&head[0], 4},
-		{&from[0], uint64(len(from))},
-	}
 	for {
-		n, _, errno := syscall.Syscall(syscall.SYS_WRITEV, uintptr(t.fd), uintptr(unsafe.Pointer(&iovecs[0])), 2)
-		if errno == 0 {
-			return int(n) - 4, nil
+		n, err := unix.Write(t.fd, from)
+		if err == nil {
+			return n, nil
 		}
-		switch errno {
+		switch err {
 		case unix.EAGAIN:
-			if err := t.blockOnWrite(); err != nil {
-				return 0, err
+			if berr := t.blockOnWrite(); berr != nil {
+				return 0, berr
 			}
 		case unix.EINTR:
 			// retry
 		case unix.EBADF:
 			return 0, os.ErrClosed
 		default:
-			return 0, errno
+			return 0, err
 		}
 	}
 }
@@ -578,8 +534,8 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for freebsd")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for freebsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
@@ -606,14 +562,6 @@ 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 {
@@ -753,3 +701,7 @@ func getLinkAddr(name string) (*netroute.LinkAddr, error) {
 
 	return nil, nil
 }
+
+// TunPrefixLen reports the 4-byte BSD AF_INET / AF_INET6 protocol-family
+// marker the kernel prepends on read and expects on write.
+func (t *tun) TunPrefixLen() int { return 4 }

overlay/tun_ios.go

@@ -4,53 +4,27 @@
 package overlay
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"log/slog"
 	"net/netip"
 	"os"
-	"sync"
 	"sync/atomic"
-	"syscall"
 
 	"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 {
-	rwc         io.ReadWriteCloser
+	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")
 }
@@ -58,9 +32,9 @@ 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,
-		rwc:         &tunReadCloser{f: file},
-		l:           l,
+		vpnNetworks:     vpnNetworks,
+		ReadWriteCloser: file,
+		l:               l,
 	}
 
 	err := t.reload(c, true)
@@ -108,55 +82,6 @@ func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
 	return r
 }
 
-// The following is hoisted up from water, we do this so we can inject our own fd on iOS
-type tunReadCloser struct {
-	f io.ReadWriteCloser
-
-	rMu  sync.Mutex
-	rBuf []byte
-
-	wMu  sync.Mutex
-	wBuf []byte
-}
-
-// Read returns a packet with the BSD 4-byte header, watch out!
-func (tr *tunReadCloser) Read(to []byte) (int, error) {
-	return tr.f.Read(to)
-}
-
-func (tr *tunReadCloser) Write(from []byte) (int, error) {
-	if len(from) == 0 {
-		return 0, syscall.EIO
-	}
-
-	tr.wMu.Lock()
-	defer tr.wMu.Unlock()
-
-	if cap(tr.wBuf) < len(from)+4 {
-		tr.wBuf = make([]byte, len(from)+4)
-	}
-	tr.wBuf = tr.wBuf[:len(from)+4]
-
-	// Determine the IP Family for the NULL L2 Header
-	ipVer := from[0] >> 4
-	if ipVer == 4 {
-		tr.wBuf[3] = syscall.AF_INET
-	} else if ipVer == 6 {
-		tr.wBuf[3] = syscall.AF_INET6
-	} else {
-		return 0, errors.New("unable to determine IP version from packet")
-	}
-
-	copy(tr.wBuf[4:], from)
-
-	n, err := tr.f.Write(tr.wBuf)
-	return n - 4, err
-}
-
-func (tr *tunReadCloser) Close() error {
-	return tr.f.Close()
-}
-
 func (t *tun) Networks() []netip.Prefix {
 	return t.vpnNetworks
 }
@@ -169,14 +94,10 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for ios")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, 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{}
-}
+// TunPrefixLen reports the 4-byte BSD AF_INET / AF_INET6 protocol-family
+// marker the kernel prepends on read and expects on write.
+func (t *tun) TunPrefixLen() int { return 4 }

overlay/tun_linux.go

@@ -4,7 +4,9 @@
 package overlay
 
 import (
+	"encoding/binary"
 	"fmt"
+	"io"
 	"log/slog"
 	"net"
 	"net/netip"
@@ -17,15 +19,180 @@ 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 {
-	readers     tio.QueueSet
+	*tunFile
+	readers     []*tunFile
 	closeLock   sync.Mutex
 	Device      string
 	vpnNetworks []netip.Prefix
@@ -72,9 +239,7 @@ type ifreqQLEN struct {
 }
 
 func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip.Prefix) (*tun, error) {
-	// 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)
+	t, err := newTunGeneric(c, l, deviceFd, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -84,60 +249,46 @@ func newTunFromFd(c *config.C, l *slog.Logger, deviceFd int, vpnNetworks []netip
 	return t, nil
 }
 
-// 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 {
-		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 = 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)
+	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
+		}
+	}
+
+	var req ifReq
+	req.Flags = uint16(unix.IFF_TUN | unix.IFF_NO_PI)
 	if multiqueue {
-		baseFlags |= unix.IFF_MULTI_QUEUE
+		req.Flags |= unix.IFF_MULTI_QUEUE
 	}
 	nameStr := c.GetString("tun.dev", "")
-
-	fd, err := openTunDev()
-	if err != nil {
-		return nil, err
-	}
-
-	name, err := tunSetIff(fd, nameStr, baseFlags)
-	if err != nil {
+	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}
+		return nil, &NameError{
+			Name:       nameStr,
+			Underlying: err,
+		}
 	}
+	name := strings.Trim(string(req.Name[:]), "\x00")
 
-	t, err := newTunGeneric(c, l, fd, false, false, vpnNetworks)
+	t, err := newTunGeneric(c, l, fd, vpnNetworks)
 	if err != nil {
 		return nil, err
 	}
@@ -148,21 +299,15 @@ 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, vnetHdr, usoEnabled bool, vpnNetworks []netip.Prefix) (*tun, error) {
-	qs, err := tio.NewPollQueueSet()
-
+func newTunGeneric(c *config.C, l *slog.Logger, fd int, vpnNetworks []netip.Prefix) (*tun, error) {
+	tfd, err := newTunFd(fd)
 	if err != nil {
 		_ = unix.Close(fd)
 		return nil, err
 	}
-	err = qs.Add(fd)
-	if err != nil {
-		_ = unix.Close(fd)
-		return nil, err
-	}
-
 	t := &tun{
-		readers:                   qs,
+		tunFile:                   tfd,
+		readers:                   []*tunFile{tfd},
 		closeLock:                 sync.Mutex{},
 		vpnNetworks:               vpnNetworks,
 		TXQueueLen:                c.GetInt("tun.tx_queue", 500),
@@ -265,29 +410,32 @@ func (t *tun) SupportsMultiqueue() bool {
 	return true
 }
 
-func (t *tun) NewMultiQueueReader() error {
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
 	t.closeLock.Lock()
 	defer t.closeLock.Unlock()
 
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	flags := uint16(unix.IFF_TUN | unix.IFF_NO_PI | unix.IFF_MULTI_QUEUE)
-
-	if _, err = tunSetIff(fd, t.Device, flags); err != nil {
+	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 {
 		_ = unix.Close(fd)
-		return err
+		return nil, err
 	}
 
-	err = t.readers.Add(fd)
+	out, err := t.tunFile.newFriend(fd)
 	if err != nil {
 		_ = unix.Close(fd)
-		return err
+		return nil, err
 	}
 
-	return nil
+	t.readers = append(t.readers, out)
+
+	return out, nil
 }
 
 func (t *tun) RoutesFor(ip netip.Addr) routing.Gateways {
@@ -455,15 +603,6 @@ 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)
@@ -730,10 +869,6 @@ 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()
@@ -743,10 +878,34 @@ 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
 	}
 
-	return t.readers.Close()
+	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
 }
+
+func (t *tun) TunPrefixLen() int { return 0 }

overlay/tun_linux_test.go

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

overlay/tun_netbsd.go

@@ -6,6 +6,7 @@ package overlay
 import (
 	"errors"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -16,10 +17,8 @@ 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"
 )
@@ -59,37 +58,16 @@ type addrLifetime struct {
 }
 
 type tun struct {
+	io.ReadWriteCloser
 	Device      string
 	vpnNetworks []netip.Prefix
 	MTU         int
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	l           *slog.Logger
-	f           *os.File
 	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) {
@@ -118,12 +96,12 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 	}
 
 	t := &tun{
-		f:           os.NewFile(uintptr(fd), ""),
-		fd:          fd,
-		Device:      deviceName,
-		vpnNetworks: vpnNetworks,
-		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		l:           l,
+		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
+		fd:              fd,
+		Device:          deviceName,
+		vpnNetworks:     vpnNetworks,
+		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		l:               l,
 	}
 
 	err = t.reload(c, true)
@@ -142,12 +120,12 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 }
 
 func (t *tun) Close() error {
-	if t.f != nil {
-		if err := t.f.Close(); err != nil {
+	if t.ReadWriteCloser != nil {
+		if err := t.ReadWriteCloser.Close(); err != nil {
 			return fmt.Errorf("error closing tun file: %w", err)
 		}
 
-		// t.f.Close should have handled it for us but let's be extra sure
+		// Close on the os.File should have handled the fd for us but let's be extra sure
 		_ = unix.Close(t.fd)
 
 		s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_IP)
@@ -163,99 +141,6 @@ func (t *tun) Close() error {
 	return nil
 }
 
-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)
-	}
-
-	var errno syscall.Errno
-	var n uintptr
-	err = rc.Read(func(fd uintptr) bool {
-		// first 4 bytes is protocol family, in network byte order
-		head := [4]byte{}
-		iovecs := []syscall.Iovec{
-			{&head[0], 4},
-			{&to[0], uint64(len(to))},
-		}
-
-		n, _, errno = syscall.Syscall(syscall.SYS_READV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
-		if errno.Temporary() {
-			// We got an EAGAIN, EINTR, or EWOULDBLOCK, go again
-			return false
-		}
-		return true
-	})
-	if err != nil {
-		if err == syscall.EBADF || err.Error() == "use of closed file" {
-			// Go doesn't export poll.ErrFileClosing but happily reports it to us so here we are
-			// https://github.com/golang/go/blob/master/src/internal/poll/fd_poll_runtime.go#L121
-			return 0, os.ErrClosed
-		}
-		return 0, fmt.Errorf("failed to make read call for tun: %w", err)
-	}
-
-	if errno != 0 {
-		return 0, fmt.Errorf("failed to make inner read call for tun: %w", errno)
-	}
-
-	// fix bytes read number to exclude header
-	bytesRead := int(n)
-	if bytesRead < 0 {
-		return bytesRead, nil
-	} else if bytesRead < 4 {
-		return 0, nil
-	} else {
-		return bytesRead - 4, nil
-	}
-}
-
-// Write is only valid for single threaded use
-func (t *tun) Write(from []byte) (int, error) {
-	if len(from) <= 1 {
-		return 0, syscall.EIO
-	}
-
-	ipVer := from[0] >> 4
-	var head [4]byte
-	// first 4 bytes is protocol family, in network byte order
-	if ipVer == 4 {
-		head[3] = syscall.AF_INET
-	} else if ipVer == 6 {
-		head[3] = syscall.AF_INET6
-	} else {
-		return 0, fmt.Errorf("unable to determine IP version from packet")
-	}
-
-	rc, err := t.f.SyscallConn()
-	if err != nil {
-		return 0, err
-	}
-
-	var errno syscall.Errno
-	var n uintptr
-	err = rc.Write(func(fd uintptr) bool {
-		iovecs := []syscall.Iovec{
-			{&head[0], 4},
-			{&from[0], uint64(len(from))},
-		}
-
-		n, _, errno = syscall.Syscall(syscall.SYS_WRITEV, fd, uintptr(unsafe.Pointer(&iovecs[0])), uintptr(2))
-		// According to NetBSD documentation for TUN, writes will only return errors in which
-		// this packet will never be delivered so just go on living life.
-		return true
-	})
-	if err != nil {
-		return 0, err
-	}
-
-	if errno != 0 {
-		return 0, errno
-	}
-
-	return int(n) - 4, err
-}
-
 func (t *tun) addIp(cidr netip.Prefix) error {
 	if cidr.Addr().Is4() {
 		var req ifreqAlias4
@@ -416,8 +301,8 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for netbsd")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for netbsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
@@ -573,3 +458,7 @@ func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
 
 	return nil
 }
+
+// TunPrefixLen reports the 4-byte BSD AF_INET / AF_INET6 protocol-family
+// marker the kernel prepends on read and expects on write.
+func (t *tun) TunPrefixLen() int { return 4 }

overlay/tun_no_prefix.go

@@ -0,0 +1,10 @@
+//go:build (!darwin && !ios && !freebsd && !openbsd && !netbsd) || e2e_testing
+
+package overlay
+
+// StampTunPrefix is a no-op on platforms whose tun devices have no
+// protocol-family marker. WireBuffer only invokes it when its prefixLen
+// is non-zero, so this should never be reached on these platforms.
+func StampTunPrefix(buf []byte) error {
+	return nil
+}

overlay/tun_openbsd.go

@@ -6,6 +6,7 @@ package overlay
 import (
 	"errors"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -16,10 +17,8 @@ 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"
 )
@@ -50,29 +49,14 @@ type ifreq struct {
 }
 
 type tun struct {
+	io.ReadWriteCloser
 	Device      string
 	vpnNetworks []netip.Prefix
 	MTU         int
 	Routes      atomic.Pointer[[]Route]
 	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
 	l           *slog.Logger
-	f           *os.File
 	fd          int
-	// cache out buffer since we need to prepend 4 bytes for tun metadata
-	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]+$`)
@@ -103,12 +87,12 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 	}
 
 	t := &tun{
-		f:           os.NewFile(uintptr(fd), ""),
-		fd:          fd,
-		Device:      deviceName,
-		vpnNetworks: vpnNetworks,
-		MTU:         c.GetInt("tun.mtu", DefaultMTU),
-		l:           l,
+		ReadWriteCloser: os.NewFile(uintptr(fd), ""),
+		fd:              fd,
+		Device:          deviceName,
+		vpnNetworks:     vpnNetworks,
+		MTU:             c.GetInt("tun.mtu", DefaultMTU),
+		l:               l,
 	}
 
 	err = t.reload(c, true)
@@ -127,46 +111,17 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*t
 }
 
 func (t *tun) Close() error {
-	if t.f != nil {
-		if err := t.f.Close(); err != nil {
+	if t.ReadWriteCloser != nil {
+		if err := t.ReadWriteCloser.Close(); err != nil {
 			return fmt.Errorf("error closing tun file: %w", err)
 		}
 
-		// t.f.Close should have handled it for us but let's be extra sure
+		// Close on the os.File should have handled the fd for us but let's be extra sure
 		_ = unix.Close(t.fd)
 	}
 	return nil
 }
 
-// Write is only valid for single threaded use
-func (t *tun) Write(from []byte) (int, error) {
-	buf := t.out
-	if cap(buf) < len(from)+4 {
-		buf = make([]byte, len(from)+4)
-		t.out = buf
-	}
-	buf = buf[:len(from)+4]
-
-	if len(from) == 0 {
-		return 0, syscall.EIO
-	}
-
-	// Determine the IP Family for the NULL L2 Header
-	ipVer := from[0] >> 4
-	if ipVer == 4 {
-		buf[3] = syscall.AF_INET
-	} else if ipVer == 6 {
-		buf[3] = syscall.AF_INET6
-	} else {
-		return 0, fmt.Errorf("unable to determine IP version from packet")
-	}
-
-	copy(buf[4:], from)
-
-	n, err := t.f.Write(buf)
-	return n - 4, err
-}
-
 func (t *tun) addIp(cidr netip.Prefix) error {
 	if cidr.Addr().Is4() {
 		var req ifreqAlias4
@@ -319,8 +274,8 @@ func (t *tun) SupportsMultiqueue() bool {
 	return false
 }
 
-func (t *tun) NewMultiQueueReader() error {
-	return fmt.Errorf("TODO: multiqueue not implemented for openbsd")
+func (t *tun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for openbsd")
 }
 
 func (t *tun) addRoutes(logErrors bool) error {
@@ -371,14 +326,6 @@ 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 {
@@ -484,3 +431,7 @@ func delRoute(prefix netip.Prefix, gateways []netip.Prefix) error {
 
 	return nil
 }
+
+// TunPrefixLen reports the 4-byte BSD AF_INET / AF_INET6 protocol-family
+// marker the kernel prepends on read and expects on write.
+func (t *tun) TunPrefixLen() int { return 4 }

overlay/tun_tester.go

@@ -14,10 +14,8 @@ 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 {
@@ -164,20 +162,7 @@ func (t *TestTun) Close() error {
 	return nil
 }
 
-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) {
+func (t *TestTun) Read(b []byte) (int, error) {
 	p, ok := <-t.rxPackets
 	if !ok {
 		return 0, os.ErrClosed
@@ -192,18 +177,12 @@ 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() error {
-	return fmt.Errorf("TODO: multiqueue not implemented")
+func (t *TestTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented")
 }
+
+func (t *TestTun) TunPrefixLen() int { return 0 }

overlay/tun_windows.go

@@ -6,6 +6,7 @@ package overlay
 import (
 	"crypto"
 	"fmt"
+	"io"
 	"log/slog"
 	"net/netip"
 	"os"
@@ -17,50 +18,26 @@ 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"
 )
 
-type closer interface {
-	Close()
-}
-
 const tunGUIDLabel = "Fixed Nebula Windows GUID v1"
 
 type winTun struct {
-	Device          string
-	vpnNetworks     []netip.Prefix
-	MTU             int
-	Routes          atomic.Pointer[[]Route]
-	routeTree       atomic.Pointer[bart.Table[routing.Gateways]]
-	guid            windows.GUID
-	networkCategory networkCategory
-	setCategory     bool
-	bypassWDF       bool
-	wdfBypass       closer
-	l               *slog.Logger
+	Device      string
+	vpnNetworks []netip.Prefix
+	MTU         int
+	Routes      atomic.Pointer[[]Route]
+	routeTree   atomic.Pointer[bart.Table[routing.Gateways]]
+	l           *slog.Logger
 
 	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")
 }
@@ -77,20 +54,11 @@ func newTun(c *config.C, l *slog.Logger, vpnNetworks []netip.Prefix, _ bool) (*w
 		return nil, fmt.Errorf("generate GUID failed: %w", err)
 	}
 
-	cat, setCat, err := parseNetworkCategory(c.GetString("tun.network_category", "private"))
-	if err != nil {
-		return nil, err
-	}
-
 	t := &winTun{
-		Device:          deviceName,
-		vpnNetworks:     vpnNetworks,
-		MTU:             c.GetInt("tun.mtu", DefaultMTU),
-		guid:            *guid,
-		networkCategory: cat,
-		setCategory:     setCat,
-		bypassWDF:       c.GetBool("tun.windows_bypass_wdf", true),
-		l:               l,
+		Device:      deviceName,
+		vpnNetworks: vpnNetworks,
+		MTU:         c.GetInt("tun.mtu", DefaultMTU),
+		l:           l,
 	}
 
 	err = t.reload(c, true)
@@ -174,17 +142,6 @@ func (t *winTun) Activate() error {
 		return err
 	}
 
-	if t.setCategory {
-		// The wintun adapter takes a moment to register with the Network List
-		// Manager, so we apply the category in the background and retry until
-		// it shows up.
-		go applyNetworkCategory(t.l, t.guid, t.networkCategory)
-	}
-
-	if t.bypassWDF {
-		t.wdfBypass = installInterfaceBypass(t.l, uint64(t.tun.LUID()))
-	}
-
 	return nil
 }
 
@@ -199,8 +156,11 @@ func (t *winTun) addRoutes(logErrors bool) error {
 			continue
 		}
 
-		// Add our unsafe route as an on-link route to the nebula tun device.
-		err := luid.AddRoute(r.Cidr, unspecifiedNextHop(r.Cidr), uint32(r.Metric))
+		// Add our unsafe route
+		// Windows does not support multipath routes natively, so we install only a single route.
+		// This is not a problem as traffic will always be sent to Nebula which handles the multipath routing internally.
+		// In effect this provides multipath routing support to windows supporting loadbalancing and redundancy.
+		err := luid.AddRoute(r.Cidr, r.Via[0].Addr(), uint32(r.Metric))
 		if err != nil {
 			retErr := util.NewContextualError("Failed to add route", map[string]any{"route": r}, err)
 			if logErrors {
@@ -246,7 +206,7 @@ func (t *winTun) removeRoutes(routes []Route) error {
 		}
 
 		// See comment on luid.AddRoute
-		err := luid.DeleteRoute(r.Cidr, unspecifiedNextHop(r.Cidr))
+		err := luid.DeleteRoute(r.Cidr, r.Via[0].Addr())
 		if err != nil {
 			t.l.Error("Failed to remove route", "error", err, "route", r)
 		} else {
@@ -269,6 +229,10 @@ 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)
 }
@@ -277,16 +241,8 @@ func (t *winTun) SupportsMultiqueue() bool {
 	return false
 }
 
-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) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
 }
 
 func (t *winTun) Close() error {
@@ -302,21 +258,9 @@ func (t *winTun) Close() error {
 	_ = luid.FlushDNS(windows.AF_INET)
 	_ = luid.FlushDNS(windows.AF_INET6)
 
-	if t.wdfBypass != nil {
-		t.wdfBypass.Close()
-		t.wdfBypass = nil
-	}
-
 	return t.tun.Close()
 }
 
-func unspecifiedNextHop(p netip.Prefix) netip.Addr {
-	if p.Addr().Is4() {
-		return netip.IPv4Unspecified()
-	}
-	return netip.IPv6Unspecified()
-}
-
 func generateGUIDByDeviceName(name string) (*windows.GUID, error) {
 	// GUID is 128 bit
 	hash := crypto.MD5.New()
@@ -352,3 +296,5 @@ func checkWinTunExists() error {
 	_, err = syscall.LoadDLL(filepath.Join(filepath.Dir(myPath), "dist", "windows", "wintun", "bin", arch, "wintun.dll"))
 	return err
 }
+
+func (t *winTun) TunPrefixLen() int { return 0 }

overlay/user.go

@@ -6,9 +6,7 @@ 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) {
@@ -25,13 +23,11 @@ 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
@@ -40,23 +36,6 @@ 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
 }
@@ -71,29 +50,24 @@ func (d *UserDevice) SupportsMultiqueue() bool {
 	return true
 }
 
-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) NewMultiQueueReader() (io.ReadWriteCloser, error) {
+	return d, nil
 }
 
 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()
 	return nil
 }
+
+func (d *UserDevice) TunPrefixLen() int { return 0 }

pki.go

@@ -99,10 +99,12 @@ func (p *PKI) reloadCerts(c *config.C, initial bool) *util.ContextualError {
 	var currentState *CertState
 	if initial {
 		cipher = c.GetString("cipher", "aes")
+		//TODO: this sucks and we should make it not a global
 		switch cipher {
-		case "aes", "chachapoly":
-			// Each post-handshake CipherState in noiseutil hardcodes its own
-			// nonce endianness now, so there's nothing to set up here.
+		case "aes":
+			noiseEndianness = binary.BigEndian
+		case "chachapoly":
+			noiseEndianness = binary.LittleEndian
 		default:
 			return util.NewContextualError(
 				"unknown cipher",

punchy.go

@@ -1,70 +1,24 @@
 package nebula
 
 import (
-	"context"
 	"log/slog"
-	"net/netip"
 	"sync/atomic"
 	"time"
 
-	"github.com/rcrowley/go-metrics"
 	"github.com/slackhq/nebula/config"
-	"github.com/slackhq/nebula/header"
-	"github.com/slackhq/nebula/udp"
 )
 
-// holepunchQueueSize buffers the channel that pending holepunchJobs land on after their delay timer fires.
-const holepunchQueueSize = 64
-
-// holepunchJob is one scheduled item delivered to the worker goroutine.
-//   - target valid -> send a UDP punch to target. vpnAddr, if set, is the peer's vpn addr carried for log context.
-//   - target invalid, vpnAddr valid -> send an encrypted test packet to vpnAddr (a "punchback").
-type holepunchJob struct {
-	target  netip.AddrPort
-	vpnAddr netip.Addr
-}
-
-// lighthouseChecker is the slice of LightHouse that Punchy actually needs.
-// Defined here so Punchy doesn't take a *LightHouse dependency (LightHouse
-// already holds a *Punchy, and the bidirectional pointer reference is awkward
-// even within the same package). Tests can also substitute a fake.
-type lighthouseChecker interface {
-	IsAnyLighthouseAddr(vpnAddrs []netip.Addr) bool
-}
-
 type Punchy struct {
 	punch           atomic.Bool
 	respond         atomic.Bool
 	delay           atomic.Int64
 	respondDelay    atomic.Int64
 	punchEverything atomic.Bool
-
-	sched             *Scheduler[holepunchJob]
-	punchConn         udp.Conn
-	metricHolepunchTx metrics.Counter
-	metricPunchyTx    metrics.Counter
-
-	ctx  context.Context
-	ifce EncWriter
-	hm   *HostMap
-	lh   lighthouseChecker
-
-	l *slog.Logger
+	l               *slog.Logger
 }
 
-func NewPunchyFromConfig(l *slog.Logger, c *config.C, punchConn udp.Conn) *Punchy {
-	p := &Punchy{
-		l:              l,
-		punchConn:      punchConn,
-		sched:          NewScheduler[holepunchJob](holepunchQueueSize),
-		metricPunchyTx: metrics.GetOrRegisterCounter("messages.tx.punchy", nil),
-	}
-
-	if c.GetBool("stats.lighthouse_metrics", false) {
-		p.metricHolepunchTx = metrics.GetOrRegisterCounter("messages.tx.holepunch", nil)
-	} else {
-		p.metricHolepunchTx = metrics.NilCounter{}
-	}
+func NewPunchyFromConfig(l *slog.Logger, c *config.C) *Punchy {
+	p := &Punchy{l: l}
 
 	p.reload(c, true)
 	c.RegisterReloadCallback(func(c *config.C) {
@@ -75,7 +29,7 @@ func NewPunchyFromConfig(l *slog.Logger, c *config.C, punchConn udp.Conn) *Punch
 }
 
 func (p *Punchy) reload(c *config.C, initial bool) {
-	if initial || c.HasChanged("punchy.punch") || c.HasChanged("punchy") {
+	if initial {
 		var yes bool
 		if c.IsSet("punchy.punch") {
 			yes = c.GetBool("punchy.punch", false)
@@ -84,15 +38,16 @@ func (p *Punchy) reload(c *config.C, initial bool) {
 			yes = c.GetBool("punchy", false)
 		}
 
-		old := p.punch.Swap(yes)
-		switch {
-		case initial && yes:
+		p.punch.Store(yes)
+		if yes {
 			p.l.Info("punchy enabled")
-		case initial:
+		} else {
 			p.l.Info("punchy disabled")
-		case old != yes:
-			p.l.Info("punchy.punch changed", "punch", yes)
 		}
+
+	} else if c.HasChanged("punchy.punch") || c.HasChanged("punchy") {
+		//TODO: it should be relatively easy to support this, just need to be able to cancel the goroutine and boot it up from here
+		p.l.Warn("Changing punchy.punch with reload is not supported, ignoring.")
 	}
 
 	if initial || c.HasChanged("punchy.respond") || c.HasChanged("punch_back") {
@@ -104,132 +59,52 @@ func (p *Punchy) reload(c *config.C, initial bool) {
 			yes = c.GetBool("punch_back", false)
 		}
 
-		old := p.respond.Swap(yes)
-		if !initial && old != yes {
-			p.l.Info("punchy.respond changed", "respond", yes)
+		p.respond.Store(yes)
+
+		if !initial {
+			p.l.Info("punchy.respond changed", "respond", p.GetRespond())
 		}
 	}
 
 	//NOTE: this will not apply to any in progress operations, only the next one
 	if initial || c.HasChanged("punchy.delay") {
-		newDelay := int64(c.GetDuration("punchy.delay", time.Second))
-		old := p.delay.Swap(newDelay)
-		if !initial && old != newDelay {
-			p.l.Info("punchy.delay changed", "delay", time.Duration(newDelay))
+		p.delay.Store((int64)(c.GetDuration("punchy.delay", time.Second)))
+		if !initial {
+			p.l.Info("punchy.delay changed", "delay", p.GetDelay())
 		}
 	}
 
 	if initial || c.HasChanged("punchy.target_all_remotes") {
-		yes := c.GetBool("punchy.target_all_remotes", false)
-		old := p.punchEverything.Swap(yes)
-		if !initial && old != yes {
-			p.l.Info("punchy.target_all_remotes changed", "target_all_remotes", yes)
+		p.punchEverything.Store(c.GetBool("punchy.target_all_remotes", false))
+		if !initial {
+			p.l.Info("punchy.target_all_remotes changed", "target_all_remotes", p.GetTargetEverything())
 		}
 	}
 
 	if initial || c.HasChanged("punchy.respond_delay") {
-		newDelay := int64(c.GetDuration("punchy.respond_delay", 5*time.Second))
-		old := p.respondDelay.Swap(newDelay)
-		if !initial && old != newDelay {
-			p.l.Info("punchy.respond_delay changed", "respond_delay", time.Duration(newDelay))
+		p.respondDelay.Store((int64)(c.GetDuration("punchy.respond_delay", 5*time.Second)))
+		if !initial {
+			p.l.Info("punchy.respond_delay changed", "respond_delay", p.GetRespondDelay())
 		}
 	}
 }
 
-// Schedule queues a punch packet to target, to be sent after the configured delay.
-// vpnAddr is the peer's vpn addr, used for log context when the packet actually fires.
-// No-op if target is not a valid AddrPort or if Start has not yet been called. Safe to call from any goroutine.
-func (p *Punchy) Schedule(target netip.AddrPort, vpnAddr netip.Addr) {
-	if !target.IsValid() || p.ctx == nil {
-		return
-	}
-	p.scheduleJob(holepunchJob{target: target, vpnAddr: vpnAddr}, time.Duration(p.delay.Load()))
+func (p *Punchy) GetPunch() bool {
+	return p.punch.Load()
 }
 
-// ScheduleRespond queues a punchback test packet to vpnAddr after the configured respond delay,
-// gated on punchy.respond. No-op when respond is disabled or before Start has been called.
-func (p *Punchy) ScheduleRespond(vpnAddr netip.Addr) {
-	if !p.respond.Load() || p.ctx == nil {
-		return
-	}
-	p.scheduleJob(holepunchJob{vpnAddr: vpnAddr}, time.Duration(p.respondDelay.Load()))
+func (p *Punchy) GetRespond() bool {
+	return p.respond.Load()
 }
 
-// scheduleJob delegates to the pooled Scheduler.
-// The callback observes p.ctx so a job that becomes due after Stop is dropped instead of queued.
-func (p *Punchy) scheduleJob(job holepunchJob, delay time.Duration) {
-	p.sched.Schedule(p.ctx, job, delay)
+func (p *Punchy) GetDelay() time.Duration {
+	return (time.Duration)(p.delay.Load())
 }
 
-// SendPunch sends an immediate keepalive punch for an idle hostinfo.
-// The configured punchy.target_all_remotes mode picks the targets. Gated on punchy.punch and the lighthouse-skip rule
-// (lighthouses don't get keepalive punches because the regular update interval keeps their NAT state warm).
-func (p *Punchy) SendPunch(hostinfo *HostInfo) {
-	if !p.punch.Load() {
-		return
-	}
-	if p.lh.IsAnyLighthouseAddr(hostinfo.vpnAddrs) {
-		return
-	}
-
-	if p.punchEverything.Load() {
-		p.sendPunchToAllRemotes(hostinfo)
-	} else if hostinfo.remote.IsValid() {
-		p.metricPunchyTx.Inc(1)
-		p.punchConn.WriteTo([]byte{1}, hostinfo.remote)
-	}
+func (p *Punchy) GetRespondDelay() time.Duration {
+	return (time.Duration)(p.respondDelay.Load())
 }
 
-// SendPunchToAll punches every known remote for hostinfo, but only when punchy.target_all_remotes is enabled.
-// The connection manager calls this during outbound-only traffic: the outbound traffic itself keeps the primary's
-// NAT state warm, but non-primary remotes need separate refresh, so we fan out to all of them (the redundant
-// primary punch is harmless). Gated on punchy.punch and the lighthouse-skip rule.
-func (p *Punchy) SendPunchToAll(hostinfo *HostInfo) {
-	if !p.punchEverything.Load() {
-		return
-	}
-	if !p.punch.Load() {
-		return
-	}
-	if p.lh.IsAnyLighthouseAddr(hostinfo.vpnAddrs) {
-		return
-	}
-	p.sendPunchToAllRemotes(hostinfo)
-}
-
-func (p *Punchy) sendPunchToAllRemotes(hostinfo *HostInfo) {
-	hostinfo.remotes.ForEach(p.hm.GetPreferredRanges(), func(addr netip.AddrPort, preferred bool) {
-		p.metricPunchyTx.Inc(1)
-		p.punchConn.WriteTo([]byte{1}, addr)
-	})
-}
-
-// Start wires the runtime dependencies and spawns the scheduler worker.
-func (p *Punchy) Start(ctx context.Context, ifce EncWriter, hm *HostMap, lh lighthouseChecker) {
-	p.ctx = ctx
-	p.ifce = ifce
-	p.hm = hm
-	p.lh = lh
-
-	nb := make([]byte, 12, 12)
-	out := make([]byte, mtu)
-	empty := []byte{0}
-
-	go p.sched.Run(ctx, func(job holepunchJob) {
-		switch {
-		case job.target.IsValid():
-			if p.l.Enabled(context.Background(), slog.LevelDebug) {
-				p.l.Debug("Punching", "target", job.target, "vpnAddr", job.vpnAddr)
-			}
-			p.metricHolepunchTx.Inc(1)
-			p.punchConn.WriteTo(empty, job.target)
-		case job.vpnAddr.IsValid():
-			// A nebula test packet to the host trying to contact us.
-			// In the case of a double nat or other difficult scenario, this may help establish a tunnel.
-			if p.l.Enabled(context.Background(), slog.LevelDebug) {
-				p.l.Debug("Sending a nebula test packet", "vpnAddr", job.vpnAddr)
-			}
-			p.ifce.SendMessageToVpnAddr(header.Test, header.TestRequest, job.vpnAddr, []byte(""), nb, out)
-		}
-	})
+func (p *Punchy) GetTargetEverything() bool {
+	return p.punchEverything.Load()
 }

punchy_test.go

@@ -17,42 +17,42 @@ func TestNewPunchyFromConfig(t *testing.T) {
 	c := config.NewC(l)
 
 	// Test defaults
-	p := NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.False(t, p.punch.Load())
-	assert.False(t, p.respond.Load())
-	assert.Equal(t, time.Second, time.Duration(p.delay.Load()))
-	assert.Equal(t, 5*time.Second, time.Duration(p.respondDelay.Load()))
+	p := NewPunchyFromConfig(test.NewLogger(), c)
+	assert.False(t, p.GetPunch())
+	assert.False(t, p.GetRespond())
+	assert.Equal(t, time.Second, p.GetDelay())
+	assert.Equal(t, 5*time.Second, p.GetRespondDelay())
 
 	// punchy deprecation
 	c.Settings["punchy"] = true
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.True(t, p.punch.Load())
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.True(t, p.GetPunch())
 
 	// punchy.punch
 	c.Settings["punchy"] = map[string]any{"punch": true}
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.True(t, p.punch.Load())
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.True(t, p.GetPunch())
 
 	// punch_back deprecation
 	c.Settings["punch_back"] = true
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.True(t, p.respond.Load())
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.True(t, p.GetRespond())
 
 	// punchy.respond
 	c.Settings["punchy"] = map[string]any{"respond": true}
 	c.Settings["punch_back"] = false
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.True(t, p.respond.Load())
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.True(t, p.GetRespond())
 
 	// punchy.delay
 	c.Settings["punchy"] = map[string]any{"delay": "1m"}
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.Equal(t, time.Minute, time.Duration(p.delay.Load()))
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.Equal(t, time.Minute, p.GetDelay())
 
 	// punchy.respond_delay
 	c.Settings["punchy"] = map[string]any{"respond_delay": "1m"}
-	p = NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.Equal(t, time.Minute, time.Duration(p.respondDelay.Load()))
+	p = NewPunchyFromConfig(test.NewLogger(), c)
+	assert.Equal(t, time.Minute, p.GetRespondDelay())
 }
 
 func TestPunchy_reload(t *testing.T) {
@@ -61,34 +61,35 @@ func TestPunchy_reload(t *testing.T) {
 	delay, _ := time.ParseDuration("1m")
 	require.NoError(t, c.LoadString(`
 punchy:
-  punch: false
   delay: 1m
   respond: false
 `))
-	p := NewPunchyFromConfig(test.NewLogger(), c, nil)
-	assert.False(t, p.punch.Load())
-	assert.Equal(t, delay, time.Duration(p.delay.Load()))
-	assert.False(t, p.respond.Load())
+	p := NewPunchyFromConfig(test.NewLogger(), c)
+	assert.Equal(t, delay, p.GetDelay())
+	assert.False(t, p.GetRespond())
 
 	newDelay, _ := time.ParseDuration("10m")
 	require.NoError(t, c.ReloadConfigString(`
 punchy:
-  punch: true
   delay: 10m
   respond: true
 `))
 	p.reload(c, false)
-	assert.True(t, p.punch.Load())
-	assert.Equal(t, newDelay, time.Duration(p.delay.Load()))
-	assert.True(t, p.respond.Load())
+	assert.Equal(t, newDelay, p.GetDelay())
+	assert.True(t, p.GetRespond())
 }
 
 // The tests below pin the shape of each log line Punchy produces so changes
 // cannot silently break whatever operators are grepping for. The assertions
 // are on the structured message + attrs (e.g. "punchy.respond changed" with
-// a respond=true field) rather than a formatted string. Tests filter by
-// message rather than asserting total entry counts so unrelated info lines
-// are tolerated without being locked into the format.
+// a respond=true field) rather than a formatted string.
+//
+// Punchy.reload also emits a spurious "Changing punchy.punch with reload is
+// not supported" warning whenever any key under punchy changes, because of
+// the c.HasChanged("punchy") fallback kept for the deprecated top-level
+// punchy form. The tests filter by message rather than asserting total
+// entry counts so that warning is tolerated without being locked into
+// the format.
 
 type capturedEntry struct {
 	Level slog.Level
@@ -144,7 +145,7 @@ func TestPunchy_LogFormat_InitialEnabled(t *testing.T) {
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {punch: true}`))
 
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 
 	entry := findEntry(t, hook.entries, "punchy enabled")
 	assert.Equal(t, slog.LevelInfo, entry.Level)
@@ -156,32 +157,32 @@ func TestPunchy_LogFormat_InitialDisabled(t *testing.T) {
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {punch: false}`))
 
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 
 	entry := findEntry(t, hook.entries, "punchy disabled")
 	assert.Equal(t, slog.LevelInfo, entry.Level)
 	assert.Empty(t, entry.Attrs)
 }
 
-func TestPunchy_LogFormat_ReloadPunch(t *testing.T) {
+func TestPunchy_LogFormat_ReloadPunchUnsupported(t *testing.T) {
 	l, hook := newCapturingPunchyLogger(t)
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {punch: false}`))
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 	hook.entries = nil
 
 	require.NoError(t, c.ReloadConfigString(`punchy: {punch: true}`))
 
-	entry := findEntry(t, hook.entries, "punchy.punch changed")
-	assert.Equal(t, slog.LevelInfo, entry.Level)
-	assert.Equal(t, map[string]any{"punch": true}, entry.Attrs)
+	entry := findEntry(t, hook.entries, "Changing punchy.punch with reload is not supported, ignoring.")
+	assert.Equal(t, slog.LevelWarn, entry.Level)
+	assert.Empty(t, entry.Attrs)
 }
 
 func TestPunchy_LogFormat_ReloadRespond(t *testing.T) {
 	l, hook := newCapturingPunchyLogger(t)
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {respond: false}`))
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 	hook.entries = nil
 
 	require.NoError(t, c.ReloadConfigString(`punchy: {respond: true}`))
@@ -195,7 +196,7 @@ func TestPunchy_LogFormat_ReloadDelay(t *testing.T) {
 	l, hook := newCapturingPunchyLogger(t)
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {delay: 1s}`))
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 	hook.entries = nil
 
 	require.NoError(t, c.ReloadConfigString(`punchy: {delay: 10s}`))
@@ -209,7 +210,7 @@ func TestPunchy_LogFormat_ReloadTargetAllRemotes(t *testing.T) {
 	l, hook := newCapturingPunchyLogger(t)
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {target_all_remotes: false}`))
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 	hook.entries = nil
 
 	require.NoError(t, c.ReloadConfigString(`punchy: {target_all_remotes: true}`))
@@ -223,7 +224,7 @@ func TestPunchy_LogFormat_ReloadRespondDelay(t *testing.T) {
 	l, hook := newCapturingPunchyLogger(t)
 	c := config.NewC(test.NewLogger())
 	require.NoError(t, c.LoadString(`punchy: {respond_delay: 5s}`))
-	NewPunchyFromConfig(l, c, nil)
+	NewPunchyFromConfig(l, c)
 	hook.entries = nil
 
 	require.NoError(t, c.ReloadConfigString(`punchy: {respond_delay: 15s}`))

relay_manager.go

@@ -63,6 +63,9 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hostinfo *Ho
 	}
 
 	hostinfo.logger(rm.l).Info("Attempt to relay through hosts", "relays", hostinfo.remotes.relays)
+	// One WireBuffer for the whole relay-fanout loop.
+	buf := f.bufAlloc.Acquire()
+	defer f.bufAlloc.Release(buf)
 	// Send a RelayRequest to all known Relay IP's
 	for _, relay := range hostinfo.remotes.relays {
 		// Don't relay through the host I'm trying to connect to
@@ -124,7 +127,7 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hostinfo *Ho
 				if err != nil {
 					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))
+					f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, buf)
 					rm.l.Info("send CreateRelayRequest",
 						"relayFrom", f.myVpnAddrs[0],
 						"relayTo", vpnIp,
@@ -139,7 +142,7 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hostinfo *Ho
 		switch existingRelay.State {
 		case Established:
 			hostinfo.logger(rm.l).Info("Send handshake via relay", "relay", relay.String())
-			f.SendVia(relayHostInfo, existingRelay, stage0, make([]byte, 12), make([]byte, mtu), false)
+			f.SendVia(relayHostInfo, existingRelay, stage0, buf)
 		case Disestablished:
 			// Mark this relay as 'requested'
 			relayHostInfo.relayState.UpdateRelayForByIpState(vpnIp, Requested)
@@ -180,7 +183,7 @@ func (rm *relayManager) StartRelays(f *Interface, vpnIp netip.Addr, hostinfo *Ho
 				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))
+				f.SendMessageToHostInfo(header.Control, 0, relayHostInfo, msg, buf)
 				rm.l.Info("send CreateRelayRequest",
 					"relayFrom", f.myVpnAddrs[0],
 					"relayTo", vpnIp,
@@ -368,7 +371,9 @@ func (rm *relayManager) handleCreateRelayResponse(v cert.Version, h *HostInfo, f
 		if err != nil {
 			rm.l.Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay", "error", err)
 		} else {
-			f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, make([]byte, 12), make([]byte, mtu))
+			buf := f.bufAlloc.Acquire()
+			f.SendMessageToHostInfo(header.Control, 0, peerHostInfo, msg, buf)
+			f.bufAlloc.Release(buf)
 			rm.l.Info("send CreateRelayResponse",
 				"relayFrom", resp.RelayFromAddr,
 				"relayTo", resp.RelayToAddr,
@@ -468,7 +473,9 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 		if err != nil {
 			logMsg.Error("relayManager Failed to marshal Control CreateRelayResponse message to create relay", "error", err)
 		} else {
-			f.SendMessageToHostInfo(header.Control, 0, h, msg, make([]byte, 12), make([]byte, mtu))
+			buf := f.bufAlloc.Acquire()
+			f.SendMessageToHostInfo(header.Control, 0, h, msg, buf)
+			f.bufAlloc.Release(buf)
 			rm.l.Info("send CreateRelayResponse",
 				"relayFrom", from,
 				"relayTo", target,
@@ -538,7 +545,9 @@ func (rm *relayManager) handleCreateRelayRequest(v cert.Version, h *HostInfo, f
 		if err != nil {
 			logMsg.Error("relayManager Failed to marshal Control message to create relay", "error", err)
 		} else {
-			f.SendMessageToHostInfo(header.Control, 0, peer, msg, make([]byte, 12), make([]byte, mtu))
+			buf := f.bufAlloc.Acquire()
+			f.SendMessageToHostInfo(header.Control, 0, peer, msg, buf)
+			f.bufAlloc.Release(buf)
 			rm.l.Info("send CreateRelayRequest",
 				"relayFrom", h.vpnAddrs[0],
 				"relayTo", target,

scheduler.go

@@ -1,84 +0,0 @@
-package nebula
-
-import (
-	"context"
-	"sync"
-	"time"
-)
-
-// Scheduler is an allocation-conscious dispatch primitive for delayed work.
-// Pending items are handed to time.AfterFunc, and ready items land on a worker
-// channel for centralized dispatch in fire-time order.
-//
-// Pick a Scheduler when fire timing matters (exact deadlines, no bucketing) or when the scheduling
-// rate is uneven enough that idle CPU matters. Each fire is a runtime-spawned goroutine running the callback before
-// delivering to the worker, which is fine at sparse rates but adds up at line rate.
-//
-// Pick a TimerWheel when scheduling is high-rate and uniform: its O(1) insert, internal item cache,
-// and bucket-batched dispatch are cheaper at scale.
-// The caller drives the tick loop (Advance/Purge) and pays for fires at bucket boundaries rather than exact deadlines.
-type Scheduler[T any] struct {
-	queue chan T
-	pool  sync.Pool
-}
-
-type schedItem[T any] struct {
-	val   T
-	ctx   context.Context
-	s     *Scheduler[T]
-	timer *time.Timer
-	fire  func()
-}
-
-// NewScheduler builds a Scheduler whose worker channel is sized to queueSize.
-// The buffer absorbs bursts of timers firing close together without
-// blocking the runtime's callback goroutines on the worker.
-func NewScheduler[T any](queueSize int) *Scheduler[T] {
-	s := &Scheduler[T]{
-		queue: make(chan T, queueSize),
-	}
-	s.pool.New = func() any {
-		si := &schedItem[T]{s: s}
-		// fire is allocated exactly once per pool-resident item.
-		// The closure captures only `si`, which stays stable for the item's lifetime.
-		si.fire = func() {
-			select {
-			case si.s.queue <- si.val:
-			case <-si.ctx.Done():
-			}
-			var zero T
-			si.val = zero
-			si.ctx = nil
-			si.s.pool.Put(si)
-		}
-		return si
-	}
-	return s
-}
-
-// Schedule arranges item to be delivered to the worker after delay.
-// The runtime's timer heap handles the wait, so the scheduler itself burns no CPU while idle.
-// The callback observes ctx: if ctx is cancelled before the timer fires, the item is dropped instead of queued.
-func (s *Scheduler[T]) Schedule(ctx context.Context, item T, delay time.Duration) {
-	si := s.pool.Get().(*schedItem[T])
-	si.val = item
-	si.ctx = ctx
-	if si.timer == nil {
-		si.timer = time.AfterFunc(delay, si.fire)
-	} else {
-		si.timer.Reset(delay)
-	}
-}
-
-// Run drains the worker queue, calling fn for each item. Returns when ctx is cancelled.
-// Tests that want deterministic timing should drive the queue directly rather than going through Schedule + Run.
-func (s *Scheduler[T]) Run(ctx context.Context, fn func(T)) {
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		case item := <-s.queue:
-			fn(item)
-		}
-	}
-}

scheduler_test.go

@@ -1,79 +0,0 @@
-package nebula
-
-import (
-	"context"
-	"testing"
-	"time"
-)
-
-func TestScheduler_PooledReuse(t *testing.T) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	s := NewScheduler[int](16)
-	delivered := make(chan int, 256)
-	go s.Run(ctx, func(item int) { delivered <- item })
-
-	const N = 100
-	for i := 0; i < N; i++ {
-		s.Schedule(ctx, i, time.Millisecond)
-	}
-
-	deadline := time.After(2 * time.Second)
-	got := 0
-	for got < N {
-		select {
-		case <-delivered:
-			got++
-		case <-deadline:
-			t.Fatalf("only %d/%d items delivered", got, N)
-		}
-	}
-}
-
-// BenchmarkScheduler_Schedule reports allocations per Schedule call.
-// In steady state the Scheduler's sync.Pool means we should see zero allocs per op once the pool warms up.
-func BenchmarkScheduler_Schedule(b *testing.B) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	s := NewScheduler[int](b.N)
-	go s.Run(ctx, func(int) {})
-
-	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		s.Schedule(ctx, i, time.Microsecond)
-	}
-}
-
-// BenchmarkBareAfterFunc is the comparison baseline.
-// What we'd pay per Schedule if Punchy called time.AfterFunc directly without the pooled Scheduler.
-// Allocates a *time.Timer plus a closure each call.
-func BenchmarkBareAfterFunc(b *testing.B) {
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	queue := make(chan int, b.N)
-	go func() {
-		for {
-			select {
-			case <-ctx.Done():
-				return
-			case <-queue:
-			}
-		}
-	}()
-
-	b.ReportAllocs()
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		i := i
-		time.AfterFunc(time.Microsecond, func() {
-			select {
-			case queue <- i:
-			case <-ctx.Done():
-			}
-		})
-	}
-}

ssh.go

@@ -632,15 +632,9 @@ func sshCloseTunnel(ifce *Interface, fs any, a []string, w sshd.StringWriter) er
 	}
 
 	if !flags.LocalOnly {
-		ifce.send(
-			header.CloseTunnel,
-			0,
-			hostInfo.ConnectionState,
-			hostInfo,
-			[]byte{},
-			make([]byte, 12, 12),
-			make([]byte, mtu),
-		)
+		buf := ifce.bufAlloc.Acquire()
+		ifce.send(header.CloseTunnel, 0, hostInfo.ConnectionState, hostInfo, []byte{}, buf)
+		ifce.bufAlloc.Release(buf)
 	}
 
 	ifce.closeTunnel(hostInfo)

sshd/server.go

@@ -27,20 +27,21 @@ type SSHServer struct {
 	commands    *radix.Tree
 	listener    net.Listener
 
-	// ctx parents per-Run contexts. Cancelling it (e.g. via Control.Stop) tears the server down even
-	// across reloads, since each Run derives a fresh child rather than reusing this one directly.
-	ctx context.Context
+	// Call the cancel() function to stop all active sessions
+	ctx    context.Context
+	cancel func()
 }
 
-// NewSSHServer creates a new ssh server rigged with default commands and prepares to listen.
-// The ssh server's context is parented off the supplied ctx so cancelling it
-// (e.g. on Control.Stop) tears down active sessions and closes the listener.
-func NewSSHServer(ctx context.Context, l *slog.Logger) (*SSHServer, error) {
+// NewSSHServer creates a new ssh server rigged with default commands and prepares to listen
+func NewSSHServer(l *slog.Logger) (*SSHServer, error) {
+
+	ctx, cancel := context.WithCancel(context.Background())
 	s := &SSHServer{
 		trustedKeys: make(map[string]map[string]bool),
 		l:           l,
 		commands:    radix.New(),
 		ctx:         ctx,
+		cancel:      cancel,
 	}
 
 	cc := ssh.CertChecker{
@@ -150,51 +151,28 @@ func (s *SSHServer) RegisterCommand(c *Command) {
 	s.commands.Insert(c.Name, c)
 }
 
-// Run begins listening and accepting connections. Each invocation derives a fresh per-Run context
-// from the constructor-supplied ctx so a Stop+Run sequence (used by config reload) starts clean
-// rather than carrying a permanently-cancelled context across runs.
+// Run begins listening and accepting connections
 func (s *SSHServer) Run(addr string) error {
-	if s.ctx.Err() != nil {
-		return s.ctx.Err()
-	}
-
-	listener, err := net.Listen("tcp", addr)
+	var err error
+	s.listener, err = net.Listen("tcp", addr)
 	if err != nil {
 		return err
 	}
-	// s.listener is the public handle Stop uses to interrupt the active run; listener (the local) is what
-	// this run owns. They start equal but a fast reload may overwrite s.listener with the next run's
-	// listener before this run's watcher fires, so each run must close its own listener via the local
-	// reference.
-	s.listener = listener
-
-	runCtx, cancel := context.WithCancel(s.ctx)
-	defer cancel()
-
-	// Close the listener when this run's context is cancelled. That can come from the parent
-	// (Control.Stop), from Run returning normally (defer cancel above), or transitively when a sibling
-	// run cancels through Stop closing the listener. net.Listener.Close is idempotent so a duplicate
-	// close from Stop is benign.
-	go func() {
-		<-runCtx.Done()
-		if err := listener.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
-			s.l.Warn("Failed to close the sshd listener", "error", err)
-		}
-	}()
 
 	s.l.Info("SSH server is listening", "sshListener", addr)
 
 	// Run loops until there is an error
-	s.run(runCtx, listener)
+	s.run()
+	s.closeSessions()
 
 	s.l.Info("SSH server stopped listening")
 	// We don't return an error because run logs for us
 	return nil
 }
 
-func (s *SSHServer) run(ctx context.Context, listener net.Listener) {
+func (s *SSHServer) run() {
 	for {
-		c, err := listener.Accept()
+		c, err := s.listener.Accept()
 		if err != nil {
 			if !errors.Is(err, net.ErrClosed) {
 				s.l.Warn("Error in listener, shutting down", "error", err)
@@ -206,7 +184,7 @@ func (s *SSHServer) run(ctx context.Context, listener net.Listener) {
 			// Ensure that a bad client doesn't hurt us by checking for the parent context
 			// cancellation before calling NewServerConn, and forcing the socket to close when
 			// the context is cancelled.
-			sessionContext, sessionCancel := context.WithCancel(ctx)
+			sessionContext, sessionCancel := context.WithCancel(s.ctx)
 			go func() {
 				<-sessionContext.Done()
 				c.Close()
@@ -249,9 +227,14 @@ func (s *SSHServer) run(ctx context.Context, listener net.Listener) {
 }
 
 func (s *SSHServer) Stop() {
+	// Close the listener, this will cause all session to terminate as well, see SSHServer.Run
 	if s.listener != nil {
 		if err := s.listener.Close(); err != nil {
 			s.l.Warn("Failed to close the sshd listener", "error", err)
 		}
 	}
 }
+
+func (s *SSHServer) closeSessions() {
+	s.cancel()
+}

timeout.go

@@ -8,23 +8,6 @@ import (
 // How many timer objects should be cached
 const timerCacheMax = 50000
 
-// TimerWheel is a hashed timing wheel: a fixed slot array indexed by (now + delay) % wheelLen,
-// with each slot a singly linked list of items due in that bucket.
-// Adds are O(1), Purges return items in arrival-within-slot order, and an internal cache of TimeoutItems
-// keeps steady-state inserts allocation-free.
-//
-// The TimerWheel does not handle concurrency or lifecycle on its own.
-// Callers drive Advance/Purge from their own ticker loop, take their own locks (or use LockingTimerWheel),
-// and decide whether to keep ticking when the wheel is empty.
-//
-// Pick a TimerWheel when scheduling is high-rate and uniform: line-rate conntrack inserts,
-// per-tunnel traffic checks at fixed intervals. O(1) insert plus the item cache means the hot path doesn't allocate.
-// Items added in the same tick are dispatched together when that slot rotates current,
-// which amortizes the cost of waking the worker.
-//
-// Pick a Scheduler when delay precision matters or scheduling is sparse or uneven.
-// The wheel rounds requested timeouts up to its tick resolution and clamps anything beyond its wheel duration;
-// both are silent in this implementation.
 type TimerWheel[T any] struct {
 	// Current tick
 	current int

udp/conn.go

@@ -8,49 +8,16 @@ 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 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
+	ListenOut(r EncReader) 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
@@ -64,7 +31,7 @@ func (NoopConn) Rebind() error {
 func (NoopConn) LocalAddr() (netip.AddrPort, error) {
 	return netip.AddrPort{}, nil
 }
-func (NoopConn) ListenOut(_ EncReader, _ func()) error {
+func (NoopConn) ListenOut(_ EncReader) error {
 	return nil
 }
 func (NoopConn) SupportsMultipleReaders() bool {
@@ -73,9 +40,6 @@ 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_android.go

@@ -5,11 +5,12 @@ package udp
 
 import (
 	"fmt"
-	"log/slog"
 	"net"
 	"net/netip"
 	"syscall"
 
+	"log/slog"
+
 	"golang.org/x/sys/unix"
 )
 

udp/udp_bsd.go

@@ -8,11 +8,12 @@ package udp
 
 import (
 	"fmt"
-	"log/slog"
 	"net"
 	"net/netip"
 	"syscall"
 
+	"log/slog"
+
 	"golang.org/x/sys/unix"
 )
 

udp/udp_bypass_windows.go

@@ -1,57 +0,0 @@
-//go:build (amd64 || arm64) && !e2e_testing
-// +build amd64 arm64
-// +build !e2e_testing
-
-package udp
-
-import (
-	"log/slog"
-	"sync"
-
-	"github.com/slackhq/nebula/config"
-	"github.com/slackhq/nebula/wfp"
-)
-
-// wrapWithWDFBypass wraps a Conn so that the first ReloadConfig consults listen.windows_bypass_wdf
-// and installs a WFP PERMIT filter for the listener's bound UDP port. The session is released when Close runs.
-func wrapWithWDFBypass(l *slog.Logger, conn Conn) Conn {
-	return &bypassConn{Conn: conn, l: l}
-}
-
-type bypassConn struct {
-	Conn
-
-	l           *slog.Logger
-	installOnce sync.Once
-	session     *wfp.Session
-}
-
-func (b *bypassConn) ReloadConfig(c *config.C) {
-	b.installOnce.Do(func() {
-		if !c.GetBool("listen.windows_bypass_wdf", true) {
-			return
-		}
-		addr, err := b.Conn.LocalAddr()
-		if err != nil {
-			b.l.Warn("Failed to query listener port for WFP bypass", "error", err)
-			return
-		}
-		s, err := wfp.PermitUDPPort(addr.Port())
-		if err != nil {
-			b.l.Warn("Failed to install WFP bypass filters for listener", "error", err)
-			return
-		}
-		b.l.Info("Installed WFP filters bypassing Windows Defender Firewall on UDP listener port",
-			"port", addr.Port())
-		b.session = s
-	})
-	b.Conn.ReloadConfig(c)
-}
-
-func (b *bypassConn) Close() error {
-	if b.session != nil {
-		b.session.Close()
-		b.session = nil
-	}
-	return b.Conn.Close()
-}

udp/udp_bypass_windows_386.go

@@ -1,11 +0,0 @@
-//go:build !e2e_testing
-// +build !e2e_testing
-
-package udp
-
-import "log/slog"
-
-// wrapWithWDFBypass is a no-op on windows-386 since we don't currently build for it.
-func wrapWithWDFBypass(_ *slog.Logger, conn Conn) Conn {
-	return conn
-}

udp/udp_darwin.go

@@ -140,15 +140,6 @@ 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()
 
@@ -174,7 +165,7 @@ func NewUDPStatsEmitter(udpConns []Conn) func() {
 	return func() {}
 }
 
-func (u *StdConn) ListenOut(r EncReader, flush func()) error {
+func (u *StdConn) ListenOut(r EncReader) error {
 	buffer := make([]byte, MTU)
 
 	for {
@@ -188,8 +179,7 @@ func (u *StdConn) ListenOut(r EncReader, flush func()) error {
 			u.l.Error("unexpected udp socket receive error", "error", err)
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], RxMeta{})
-		flush()
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
 	}
 }
 

udp/udp_generic.go

@@ -44,15 +44,6 @@ 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()
 
@@ -82,7 +73,7 @@ type rawMessage struct {
 	Len uint32
 }
 
-func (u *GenericConn) ListenOut(r EncReader, flush func()) error {
+func (u *GenericConn) ListenOut(r EncReader) error {
 	buffer := make([]byte, MTU)
 
 	var lastRecvErr time.Time
@@ -102,8 +93,7 @@ func (u *GenericConn) ListenOut(r EncReader, flush func()) error {
 			continue
 		}
 
-		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n], RxMeta{})
-		flush()
+		r(netip.AddrPortFrom(rua.Addr().Unmap(), rua.Port()), buffer[:n])
 	}
 }
 

udp/udp_linux.go

@@ -24,22 +24,6 @@ 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 {
@@ -86,23 +70,9 @@ 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
 }
@@ -201,7 +171,7 @@ func recvmmsg(fd uintptr, msgs []rawMessage) (int, bool, error) {
 	return int(n), true, nil
 }
 
-func (u *StdConn) listenOutSingle(r EncReader, flush func()) error {
+func (u *StdConn) listenOutSingle(r EncReader) error {
 	var err error
 	var n int
 	var from netip.AddrPort
@@ -213,33 +183,16 @@ func (u *StdConn) listenOutSingle(r EncReader, flush func()) error {
 			return err
 		}
 		from = netip.AddrPortFrom(from.Addr().Unmap(), from.Port())
-		// 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()
+		r(from, buffer[:n])
 	}
 }
 
-// readSockaddr decodes the source address out of a recvmmsg name buffer
-func (u *StdConn) readSockaddr(name []byte) netip.AddrPort {
+func (u *StdConn) listenOutBatch(r EncReader) error {
 	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
 
-	bufSize := MTU
-	cmsgSpace := 0
-	msgs, buffers, names, _ := u.PrepareRawMessages(u.batch, bufSize, cmsgSpace)
+	msgs, buffers, names := u.PrepareRawMessages(u.batch)
 
 	//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
@@ -258,18 +211,22 @@ func (u *StdConn) listenOutBatch(r EncReader, flush func()) error {
 		}
 
 		for i := 0; i < n; i++ {
-			r(u.readSockaddr(names[i]), buffers[i][:msgs[i].Len], RxMeta{})
+			// 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])
 		}
-
-		flush()
 	}
 }
 
-func (u *StdConn) ListenOut(r EncReader, flush func()) error {
+func (u *StdConn) ListenOut(r EncReader) error {
 	if u.batch == 1 {
-		return u.listenOutSingle(r, flush)
+		return u.listenOutSingle(r)
 	} else {
-		return u.listenOutBatch(r, flush)
+		return u.listenOutBatch(r)
 	}
 }
 
@@ -278,120 +235,6 @@ 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

@@ -30,18 +30,13 @@ type rawMessage struct {
 	Len uint32
 }
 
-func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [][]byte, [][]byte, []byte) {
+func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]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, bufSize)
+		buffers[i] = make([]byte, MTU)
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
 		vs := []iovec{
@@ -53,28 +48,7 @@ func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [
 
 		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, 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)
+	return msgs, buffers, names
 }

udp/udp_linux_64.go

@@ -33,18 +33,13 @@ type rawMessage struct {
 	Pad0 [4]byte
 }
 
-func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [][]byte, [][]byte, []byte) {
+func (u *StdConn) PrepareRawMessages(n int) ([]rawMessage, [][]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, bufSize)
+		buffers[i] = make([]byte, MTU)
 		names[i] = make([]byte, unix.SizeofSockaddrInet6)
 
 		vs := []iovec{
@@ -56,28 +51,7 @@ func (u *StdConn) PrepareRawMessages(n, bufSize, cmsgSpace int) ([]rawMessage, [
 
 		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, 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)
+	return msgs, buffers, names
 }

udp/udp_netbsd.go

@@ -7,11 +7,12 @@ package udp
 
 import (
 	"fmt"
-	"log/slog"
 	"net"
 	"net/netip"
 	"syscall"
 
+	"log/slog"
+
 	"golang.org/x/sys/unix"
 )
 

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, flush func()) error {
+func (u *RIOConn) ListenOut(r EncReader) error {
 	buffer := make([]byte, MTU)
 
 	var lastRecvErr time.Time
@@ -161,8 +161,7 @@ func (u *RIOConn) ListenOut(r EncReader, flush func()) error {
 			continue
 		}
 
-		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n], RxMeta{})
-		flush()
+		r(netip.AddrPortFrom(netip.AddrFrom16(rua.Addr).Unmap(), (rua.Port>>8)|((rua.Port&0xff)<<8)), buffer[:n])
 	}
 }
 
@@ -317,15 +316,6 @@ 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

@@ -157,24 +157,15 @@ 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, flush func()) error {
+func (u *TesterConn) ListenOut(r EncReader) error {
 	for {
 		select {
 		case <-u.done:
 			return os.ErrClosed
 		case p := <-u.RxPackets:
-			r(p.From, p.Data, RxMeta{})
+			r(p.From, p.Data)
 			p.Release()
-			flush()
 		}
 	}
 }

udp/udp_windows.go

@@ -19,18 +19,13 @@ func NewListener(l *slog.Logger, ip netip.Addr, port int, multi bool, batch int)
 		return nil, fmt.Errorf("multiple udp listeners not supported on windows")
 	}
 
-	var conn Conn
 	rc, err := NewRIOListener(l, ip, port)
 	if err == nil {
-		conn = rc
-	} else {
-		l.Error("Falling back to standard udp sockets", "error", err)
-		conn, err = NewGenericListener(l, ip, port, multi, batch)
-		if err != nil {
-			return nil, err
-		}
+		return rc, nil
 	}
-	return wrapWithWDFBypass(l, conn), nil
+
+	l.Error("Falling back to standard udp sockets", "error", err)
+	return NewGenericListener(l, ip, port, multi, batch)
 }
 
 func NewListenConfig(multi bool) net.ListenConfig {

wfp/wfp_windows.go

@@ -1,377 +0,0 @@
-//go:build (amd64 || arm64) && !e2e_testing
-// +build amd64 arm64
-// +build !e2e_testing
-
-// Package wfp installs Windows Filtering Platform (WFP) PERMIT filters in a dynamic, session-scoped sublayer.
-// Because WFP sits below Windows Defender Firewall, a high-weight permit at FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V4/V6 lets
-// the matching inbound traffic through regardless of WDF rules.
-//
-// Each Session owns its own engine handle. When the handle closes, every dynamic object added during the session
-// is auto-deleted by Windows, so there are no orphaned filters.
-//
-// Type definitions and constants are derived from the wireguard-windows firewall package (MIT).
-// Only the subset we exercise is reproduced.
-package wfp
-
-import (
-	"fmt"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-// FWPM layer GUIDs (fwpmu.h).
-//
-// FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V4 = e1cd9fe7-f4b5-4273-96c0-592e487b8650
-// FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V6 = a3b42c97-9f04-4672-b87e-cee9c483257f
-var (
-	fwpmLayerAleAuthRecvAcceptV4 = windows.GUID{
-		Data1: 0xe1cd9fe7, Data2: 0xf4b5, Data3: 0x4273,
-		Data4: [8]byte{0x96, 0xc0, 0x59, 0x2e, 0x48, 0x7b, 0x86, 0x50},
-	}
-	fwpmLayerAleAuthRecvAcceptV6 = windows.GUID{
-		Data1: 0xa3b42c97, Data2: 0x9f04, Data3: 0x4672,
-		Data4: [8]byte{0xb8, 0x7e, 0xce, 0xe9, 0xc4, 0x83, 0x25, 0x7f},
-	}
-)
-
-// FWPM_CONDITION_IP_LOCAL_INTERFACE = 4cd62a49-59c3-4969-b7f3-bda5d32890a4
-var fwpmConditionIPLocalInterface = windows.GUID{
-	Data1: 0x4cd62a49, Data2: 0x59c3, Data3: 0x4969,
-	Data4: [8]byte{0xb7, 0xf3, 0xbd, 0xa5, 0xd3, 0x28, 0x90, 0xa4},
-}
-
-// FWPM_CONDITION_IP_PROTOCOL = 3971ef2b-623e-4f9a-8cb1-6e79b806b9a7
-var fwpmConditionIPProtocol = windows.GUID{
-	Data1: 0x3971ef2b, Data2: 0x623e, Data3: 0x4f9a,
-	Data4: [8]byte{0x8c, 0xb1, 0x6e, 0x79, 0xb8, 0x06, 0xb9, 0xa7},
-}
-
-// FWPM_CONDITION_IP_LOCAL_PORT = 0c1ba1af-5765-453f-af22-a8f791ac775b
-var fwpmConditionIPLocalPort = windows.GUID{
-	Data1: 0x0c1ba1af, Data2: 0x5765, Data3: 0x453f,
-	Data4: [8]byte{0xaf, 0x22, 0xa8, 0xf7, 0x91, 0xac, 0x77, 0x5b},
-}
-
-// IPPROTO_UDP from in.h.
-const ipprotoUDP uint8 = 17
-
-// FWP_ACTION_TYPE values (fwptypes.h). PERMIT is terminating.
-const fwpActionPermit uint32 = 0x00001002 // 0x2 | FWP_ACTION_FLAG_TERMINATING(0x1000)
-
-// FWP_DATA_TYPE values we use.
-const (
-	fwpEmpty  uint32 = 0
-	fwpUint8  uint32 = 1
-	fwpUint16 uint32 = 2
-	fwpUint64 uint32 = 4
-)
-
-// FWP_MATCH_TYPE values.
-const fwpMatchEqual uint32 = 0
-
-// FWPM_SESSION flags.
-const fwpmSessionFlagDynamic uint32 = 0x1
-
-// FWPM_FILTER_FLAG_CLEAR_ACTION_RIGHT prevents lower-priority filters in other sublayers,
-// notably Windows Defender Firewall's MPSSVC_WF sublayer, which shares our 0xFFFF weight from overriding this PERMIT.
-// Without it, a default WDF block at the same sublayer weight can still win arbitration.
-const fwpmFilterFlagClearActionRight uint32 = 0x8
-
-// RPC authentication.
-// RPC_C_AUTHN_WINNT works on workgroup machines with no domain context
-// RPC_C_AUTHN_DEFAULT falls back through a chain that can land on something WFP doesn't accept on a fresh box.
-const rpcCAuthnWinNT uint32 = 10
-
-// fwpByteBlob (FWP_BYTE_BLOB). 16 bytes on 64-bit.
-type fwpByteBlob struct {
-	size uint32
-	_    uint32 // padding
-	data *uint8
-}
-
-// fwpValue0 / FWP_CONDITION_VALUE0 layout. 16 bytes on 64-bit.
-// The union is pointer-sized; types <= 32 bits (UINT8/16/32, INT8/16/32, float) live inline in the low bytes
-// of `value`, while UINT64/INT64/double and aggregate types are stored *by pointer*, even on 64-bit, where the
-// union member is declared as UINT64*. So when populating an FWP_UINT64 condition, pass
-// uintptr(unsafe.Pointer(&luidVar)) instead of the LUID inline.
-type fwpValue0 struct {
-	type_ uint32
-	_     uint32 // padding before union to 8-byte alignment
-	value uintptr
-}
-
-// fwpmDisplayData0 / FWPM_DISPLAY_DATA0. 16 bytes on 64-bit.
-type fwpmDisplayData0 struct {
-	name        *uint16
-	description *uint16
-}
-
-// fwpmAction0 / FWPM_ACTION0. 20 bytes; no leading padding because actionType
-// is uint32 and GUID's first field is uint32.
-type fwpmAction0 struct {
-	actionType uint32
-	filterType windows.GUID
-}
-
-// fwpmFilterCondition0. 40 bytes on 64-bit.
-type fwpmFilterCondition0 struct {
-	fieldKey       windows.GUID // 16
-	matchType      uint32       // 4
-	_              uint32       // 4 padding
-	conditionValue fwpValue0    // 16
-}
-
-// fwpmFilter0. 200 bytes on 64-bit.
-type fwpmFilter0 struct {
-	filterKey           windows.GUID
-	displayData         fwpmDisplayData0
-	flags               uint32
-	_                   uint32 // padding before *GUID
-	providerKey         *windows.GUID
-	providerData        fwpByteBlob
-	layerKey            windows.GUID
-	subLayerKey         windows.GUID
-	weight              fwpValue0
-	numFilterConditions uint32
-	_                   uint32 // padding before pointer
-	filterCondition     *fwpmFilterCondition0
-	action              fwpmAction0
-	_                   [4]byte // layout correction
-	providerContextKey  windows.GUID
-	reserved            *windows.GUID
-	filterID            uint64
-	effectiveWeight     fwpValue0
-}
-
-// fwpmSublayer0. 72 bytes on 64-bit.
-type fwpmSublayer0 struct {
-	subLayerKey  windows.GUID
-	displayData  fwpmDisplayData0
-	flags        uint32
-	_            uint32 // padding before *GUID
-	providerKey  *windows.GUID
-	providerData fwpByteBlob
-	weight       uint16
-	_            [6]byte // padding to 72 bytes
-}
-
-// fwpmSession0. 72 bytes on 64-bit.
-type fwpmSession0 struct {
-	sessionKey           windows.GUID
-	displayData          fwpmDisplayData0
-	flags                uint32
-	txnWaitTimeoutInMSec uint32
-	processId            uint32
-	_                    uint32 // padding before *SID
-	sid                  *windows.SID
-	username             *uint16
-	kernelMode           uint8
-	_                    [7]byte // tail padding
-}
-
-// fwpuclnt.dll bindings. Only the calls we use.
-var (
-	modFwpuclnt          = windows.NewLazySystemDLL("fwpuclnt.dll")
-	procFwpmEngineOpen0  = modFwpuclnt.NewProc("FwpmEngineOpen0")
-	procFwpmEngineClose0 = modFwpuclnt.NewProc("FwpmEngineClose0")
-	procFwpmSubLayerAdd0 = modFwpuclnt.NewProc("FwpmSubLayerAdd0")
-	procFwpmFilterAdd0   = modFwpuclnt.NewProc("FwpmFilterAdd0")
-)
-
-// Session holds the WFP engine handle for a single bypass operation. The handle owns a dynamic session:
-// when it is closed, every WFP object added during the session (sublayer + filters) is automatically deleted by
-// Windows. That gives us correct cleanup even if the host process is killed hard between Permit* and Close.
-type Session struct {
-	engine uintptr
-}
-
-// Close releases the engine handle. Windows deletes every dynamic object (sublayer + filters) the session installed.
-// Safe to call on a nil receiver.
-func (s *Session) Close() {
-	if s == nil || s.engine == 0 {
-		return
-	}
-	procFwpmEngineClose0.Call(s.engine)
-	s.engine = 0
-}
-
-// PermitInterface installs PERMIT filters at FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V4 and _V6 scoped to the given network
-// interface LUID. Inbound traffic on that interface bypasses Windows Defender Firewall.
-func PermitInterface(luid uint64) (*Session, error) {
-	s, sublayerKey, err := newSession()
-	if err != nil {
-		return nil, err
-	}
-
-	if err := addInterfaceFilter(s.engine, sublayerKey, fwpmLayerAleAuthRecvAcceptV4, luid); err != nil {
-		s.Close()
-		return nil, fmt.Errorf("add v4 filter: %w", err)
-	}
-	if err := addInterfaceFilter(s.engine, sublayerKey, fwpmLayerAleAuthRecvAcceptV6, luid); err != nil {
-		s.Close()
-		return nil, fmt.Errorf("add v6 filter: %w", err)
-	}
-	return s, nil
-}
-
-// PermitUDPPort installs PERMIT filters at FWPM_LAYER_ALE_AUTH_RECV_ACCEPT_V4 and _V6 scoped to UDP traffic with the
-// given local port. Inbound UDP to that port on any interface bypasses Windows Defender Firewall.
-func PermitUDPPort(port uint16) (*Session, error) {
-	s, sublayerKey, err := newSession()
-	if err != nil {
-		return nil, err
-	}
-
-	if err := addUDPPortFilter(s.engine, sublayerKey, fwpmLayerAleAuthRecvAcceptV4, port); err != nil {
-		s.Close()
-		return nil, fmt.Errorf("add v4 filter: %w", err)
-	}
-	if err := addUDPPortFilter(s.engine, sublayerKey, fwpmLayerAleAuthRecvAcceptV6, port); err != nil {
-		s.Close()
-		return nil, fmt.Errorf("add v6 filter: %w", err)
-	}
-	return s, nil
-}
-
-func newSession() (*Session, windows.GUID, error) {
-	engine, err := openDynamicEngine()
-	if err != nil {
-		return nil, windows.GUID{}, err
-	}
-	sublayerKey, err := registerSublayer(engine)
-	if err != nil {
-		procFwpmEngineClose0.Call(engine)
-		return nil, windows.GUID{}, err
-	}
-	return &Session{engine: engine}, sublayerKey, nil
-}
-
-func openDynamicEngine() (uintptr, error) {
-	session := fwpmSession0{flags: fwpmSessionFlagDynamic}
-	var engine uintptr
-	r1, _, _ := procFwpmEngineOpen0.Call(
-		0, // serverName == NULL (local)
-		uintptr(rpcCAuthnWinNT),
-		0, // authIdentity == NULL
-		uintptr(unsafe.Pointer(&session)),
-		uintptr(unsafe.Pointer(&engine)),
-	)
-	if r1 != 0 {
-		return 0, fmt.Errorf("FwpmEngineOpen0: 0x%x", r1)
-	}
-	return engine, nil
-}
-
-// registerSublayer adds a session-scoped sublayer with a freshly generated GUID, weight 0xFFFF so its filters arbitrate
-// above WDF's default sublayer. The sublayer is dynamic (no PERSISTENT flag) and goes away when the engine handle closes.
-func registerSublayer(engine uintptr) (windows.GUID, error) {
-	key, err := windows.GenerateGUID()
-	if err != nil {
-		return windows.GUID{}, fmt.Errorf("GenerateGUID for sublayer: %w", err)
-	}
-
-	name, _ := windows.UTF16PtrFromString("Nebula WDF bypass sublayer")
-	desc, _ := windows.UTF16PtrFromString("Permit filters bypassing Windows Defender Firewall")
-	sl := fwpmSublayer0{
-		subLayerKey: key,
-		displayData: fwpmDisplayData0{name: name, description: desc},
-		weight:      0xFFFF,
-	}
-	r1, _, _ := procFwpmSubLayerAdd0.Call(
-		engine,
-		uintptr(unsafe.Pointer(&sl)),
-		0, // sd == NULL
-	)
-	if r1 != 0 {
-		return windows.GUID{}, fmt.Errorf("FwpmSubLayerAdd0: 0x%x", r1)
-	}
-	return key, nil
-}
-
-func addInterfaceFilter(engine uintptr, sublayerKey, layer windows.GUID, luid uint64) error {
-	name, _ := windows.UTF16PtrFromString("Nebula allow interface inbound")
-	desc, _ := windows.UTF16PtrFromString("Permits inbound traffic on a nebula interface")
-
-	// luid must remain addressable through the syscall -- FWP_UINT64 is stored
-	// by pointer in the FWP_VALUE0 union.
-	cond := fwpmFilterCondition0{
-		fieldKey:  fwpmConditionIPLocalInterface,
-		matchType: fwpMatchEqual,
-		conditionValue: fwpValue0{
-			type_: fwpUint64,
-			value: uintptr(unsafe.Pointer(&luid)),
-		},
-	}
-
-	filter := fwpmFilter0{
-		// filterKey left zero: WFP assigns one when the filter is added.
-		displayData:         fwpmDisplayData0{name: name, description: desc},
-		flags:               fwpmFilterFlagClearActionRight,
-		layerKey:            layer,
-		subLayerKey:         sublayerKey,
-		weight:              fwpValue0{type_: fwpUint8, value: uintptr(15)},
-		numFilterConditions: 1,
-		filterCondition:     &cond,
-		action:              fwpmAction0{actionType: fwpActionPermit},
-	}
-
-	r1, _, _ := procFwpmFilterAdd0.Call(
-		engine,
-		uintptr(unsafe.Pointer(&filter)),
-		0, // sd == NULL
-		0, // id == NULL
-	)
-	if r1 != 0 {
-		return fmt.Errorf("FwpmFilterAdd0: 0x%x", r1)
-	}
-	return nil
-}
-
-// addUDPPortFilter installs a PERMIT filter that matches (IP_PROTOCOL == UDP) AND (IP_LOCAL_PORT == port).
-// FWP_UINT8 and FWP_UINT16 are <= 32 bits so they live inline in the FWP_VALUE0 union.
-func addUDPPortFilter(engine uintptr, sublayerKey, layer windows.GUID, port uint16) error {
-	name, _ := windows.UTF16PtrFromString("Nebula allow UDP port inbound")
-	desc, _ := windows.UTF16PtrFromString("Permits inbound UDP to a nebula listener port")
-
-	conds := [2]fwpmFilterCondition0{
-		{
-			fieldKey:  fwpmConditionIPProtocol,
-			matchType: fwpMatchEqual,
-			conditionValue: fwpValue0{
-				type_: fwpUint8,
-				value: uintptr(ipprotoUDP),
-			},
-		},
-		{
-			fieldKey:  fwpmConditionIPLocalPort,
-			matchType: fwpMatchEqual,
-			conditionValue: fwpValue0{
-				type_: fwpUint16,
-				value: uintptr(port),
-			},
-		},
-	}
-
-	filter := fwpmFilter0{
-		displayData:         fwpmDisplayData0{name: name, description: desc},
-		flags:               fwpmFilterFlagClearActionRight,
-		layerKey:            layer,
-		subLayerKey:         sublayerKey,
-		weight:              fwpValue0{type_: fwpUint8, value: uintptr(15)},
-		numFilterConditions: 2,
-		filterCondition:     &conds[0],
-		action:              fwpmAction0{actionType: fwpActionPermit},
-	}
-
-	r1, _, _ := procFwpmFilterAdd0.Call(
-		engine,
-		uintptr(unsafe.Pointer(&filter)),
-		0,
-		0,
-	)
-	if r1 != 0 {
-		return fmt.Errorf("FwpmFilterAdd0: 0x%x", r1)
-	}
-	return nil
-}

wire/wire.go

@@ -1,17 +0,0 @@
-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)
-}

wire_buffer.go

@@ -0,0 +1,255 @@
+package nebula
+
+import (
+	"io"
+	"sync"
+
+	"github.com/slackhq/nebula/firewall"
+	"github.com/slackhq/nebula/header"
+	"github.com/slackhq/nebula/noiseutil"
+	"github.com/slackhq/nebula/overlay"
+)
+
+// WireBuffer is the per-goroutine working set for processing one IP packet
+// through the data plane. It owns:
+//
+//   - The IP-payload byte buffer used to hold the current inbound or
+//     outbound packet, with prefixLen bytes of slack at the front for
+//     the BSD AF_INET protocol-family marker.
+//   - The fwPacket scratch parsed by newPacket().
+//   - The 12-byte AEAD nonce scratch.
+//   - The header.H parse target used by the receive path.
+//   - An mtu-sized wire-output scratch for sendNoMetrics and for building
+//     reject packets.
+//
+// One WireBuffer is allocated per data-plane goroutine (listenIn for the
+// TUN-side, listenOut for the UDP-side) and reused for every packet. No
+// per-packet allocation. Future GRO/GSO/TSO and reliable-transport work
+// will likely extend this to carry batch state and fragment metadata.
+//
+// The TUN protocol-family prefix is handled here, not in the overlay
+// package. On BSDs the kernel writes the 4-byte marker into the slack on
+// read, and we stamp it into the slack before write. On linux/windows
+// /userspace devices prefixLen is 0 and the slack is empty.
+type WireBuffer struct {
+	// FwPacket is the parsed IP packet metadata (5-tuple, fragment flags,
+	// etc.) populated by newPacket().
+	FwPacket *firewall.Packet
+	// NB is a 12-byte scratch the AEAD uses for the nonce; reused so we
+	// don't allocate one per encrypt/decrypt.
+	NB []byte
+	// H is the parse target for inbound nebula headers. Receive path only.
+	H *header.H
+	// Out is an mtu-sized wire-output scratch passed to sendNoMetrics and
+	// rejectInside / rejectOutside. Sized to fit any single wire packet.
+	Out []byte
+
+	// ip is the IP-payload region: a slice of len 0, cap linkMTU sliced
+	// from raw at offset prefixLen. The current packet (if any) is
+	// ip[:bodyN]. The TUN prefix slack lives at raw[0:prefixLen] just
+	// before ip.
+	ip []byte
+	// raw is the backing slab. Layout:
+	//   [prefixLen bytes prefix slack | linkMTU bytes IP region | outSize bytes Out scratch]
+	// Holding it lets ReadIPFromTUN / WriteIPToTUN address the slack
+	// region directly.
+	raw       []byte
+	prefixLen int
+	bodyN     int
+}
+
+// NewWireBuffer returns a buffer sized to hold any single IP packet up to
+// linkMTU, plus a disjoint wire-output scratch sliced from the same backing
+// slab (the AEAD's Seal contract requires plaintext and dst not to partially
+// overlap, and keeping them in one slab gives a single allocation per
+// goroutine). Out is sized for the relay worst case
+// (linkMTU + 2*header.Len + 2*AEADOverhead).
+//
+// prefixLen is the number of bytes the destination tun device prepends/
+// expects on each IP packet (overlay.Device.TunPrefixLen). On BSDs this
+// is 4 (AF_INET marker); on linux/windows/userspace devices it is 0.
+func NewWireBuffer(linkMTU, prefixLen int) *WireBuffer {
+	outSize := linkMTU + 2*header.Len + 2*AEADOverhead
+	raw := make([]byte, prefixLen+linkMTU+outSize)
+	outStart := prefixLen + linkMTU
+	return &WireBuffer{
+		FwPacket:  &firewall.Packet{},
+		NB:        make([]byte, NonceSize),
+		H:         &header.H{},
+		Out:       raw[outStart : outStart : outStart+outSize],
+		ip:        raw[prefixLen:prefixLen:outStart],
+		raw:       raw,
+		prefixLen: prefixLen,
+	}
+}
+
+// Reset clears the body-length record so the buffer is ready for another
+// recv (e.g. relay-receive recursion before a nested decrypt).
+func (b *WireBuffer) Reset() { b.bodyN = 0 }
+
+// IPPacket returns the IP packet currently held in the payload region (after
+// a successful ReadIPFromTUN or DecryptDatagram). The slice aliases the
+// buffer; do not retain past the next operation.
+func (b *WireBuffer) IPPacket() []byte {
+	return b.ip[:b.bodyN]
+}
+
+// Seal stamps a nebula header at the front of buf.Out and AEAD-seals p as the
+// payload, treating the header as additional authenticated data. The lock
+// scope around counter increment + encrypt matches what goboring AESGCMTLS
+// requires; non-boring builds skip the lock.
+//
+// Returns the wire bytes (header || ciphertext || tag), aliased to buf.Out.
+// The slice is invalidated by the next Seal* call on this buffer.
+func (b *WireBuffer) Seal(ci *ConnectionState, t header.MessageType, st header.MessageSubType, remoteIndex uint32, p []byte) ([]byte, error) {
+	return b.sealInto(b.Out[:cap(b.Out)], ci, t, st, remoteIndex, p)
+}
+
+// SealForRelay is like Seal but reserves header.Len bytes of slack at the front
+// of buf.Out for an outer relay header. The inner header + ciphertext lands at
+// offset header.Len so a follow-up SealRelayInPlace can stamp the outer header
+// without copying. Use this when the caller may need to wrap the result in a
+// relay envelope after the fact.
+func (b *WireBuffer) SealForRelay(ci *ConnectionState, t header.MessageType, st header.MessageSubType, remoteIndex uint32, p []byte) ([]byte, error) {
+	return b.sealInto(b.Out[header.Len:cap(b.Out)], ci, t, st, remoteIndex, p)
+}
+
+func (b *WireBuffer) sealInto(out []byte, ci *ConnectionState, t header.MessageType, st header.MessageSubType, remoteIndex uint32, p []byte) ([]byte, error) {
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Lock()
+	}
+	c := ci.messageCounter.Add(1)
+	out = header.Encode(out, header.Version, t, st, remoteIndex, c)
+	out, err := ci.eKey.EncryptDanger(out, out, p, c, b.NB)
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Unlock()
+	}
+	return out, err
+}
+
+// SealRelayInPlace wraps an inner message that is already staged at
+// buf.Out[header.Len:header.Len+innerLen] (either from a SealForRelay encrypt
+// or from a copy via the SendVia entry point). It stamps the outer relay
+// header into buf.Out[:header.Len] and AAD-only seals over the entire region,
+// producing the wire bytes for the relay tunnel.
+//
+// Returns the wire bytes aliased to buf.Out; invalidated by the next Seal*
+// call on this buffer.
+func (b *WireBuffer) SealRelayInPlace(ci *ConnectionState, remoteIndex uint32, innerLen int) ([]byte, error) {
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Lock()
+	}
+	c := ci.messageCounter.Add(1)
+	out := b.Out[:cap(b.Out)]
+	out = header.Encode(out, header.Version, header.Message, header.MessageRelay, remoteIndex, c)
+	out = out[:header.Len+innerLen]
+	out, err := ci.eKey.EncryptDanger(out, out, nil, c, b.NB)
+	if noiseutil.EncryptLockNeeded {
+		ci.writeLock.Unlock()
+	}
+	return out, err
+}
+
+// StageRelayInner copies ad into the inner-payload slot at buf.Out[header.Len:]
+// so SealRelayInPlace can wrap it on the next call. Used by SendVia when ad
+// did not come from a prior SealForRelay (e.g. a handshake message being
+// forwarded through a relay tunnel without our own encryption).
+func (b *WireBuffer) StageRelayInner(ad []byte) int {
+	return copy(b.Out[header.Len:cap(b.Out)], ad)
+}
+
+// ReadIPFromTUN reads one IP packet from r into the payload region and
+// updates bodyN. On BSDs the kernel writes its 4-byte protocol-family
+// marker into the slack at raw[0:prefixLen] and the IP packet at
+// raw[prefixLen:prefixLen+n]; we hand it the slack-prefixed slice so
+// the kernel can do this in one syscall with no copy. On linux/windows/
+// userspace devices prefixLen is 0 and the slack is empty.
+func (b *WireBuffer) ReadIPFromTUN(r io.Reader) (int, error) {
+	n, err := r.Read(b.raw[:b.prefixLen+cap(b.ip)])
+	if err != nil {
+		b.bodyN = 0
+		return 0, err
+	}
+	if n < b.prefixLen {
+		b.bodyN = 0
+		return 0, nil
+	}
+	b.bodyN = n - b.prefixLen
+	return b.bodyN, nil
+}
+
+// WriteIPToTUN writes the IP packet currently in the payload region to w.
+// On BSDs we stamp the protocol-family marker into the slack at
+// raw[0:prefixLen] in place and write the entire slack+IP region in a
+// single syscall, so the kernel sees [marker][ip] back to back without a
+// userspace copy. On linux/windows/userspace devices the slack is empty
+// and we just write the IP region.
+func (b *WireBuffer) WriteIPToTUN(w io.Writer) (int, error) {
+	out := b.raw[:b.prefixLen+b.bodyN]
+	if b.prefixLen > 0 {
+		if err := overlay.StampTunPrefix(out); err != nil {
+			return 0, err
+		}
+	}
+	return w.Write(out)
+}
+
+// DecryptDatagram decrypts an inbound UDP packet into the payload region.
+func (b *WireBuffer) DecryptDatagram(ci *ConnectionState, packet []byte, mc uint64) error {
+	dst, err := ci.dKey.DecryptDanger(b.ip[:0], packet[:header.Len], packet[header.Len:], mc, b.NB)
+	if err != nil {
+		b.bodyN = 0
+		return err
+	}
+	b.bodyN = len(dst)
+	return nil
+}
+
+// DecryptForHandler decrypts an inbound UDP packet (lighthouse, test,
+// control, close-tunnel) into the payload region and returns the plaintext
+// slice for the in-process handler. Returned slice aliases the buffer.
+func (b *WireBuffer) DecryptForHandler(ci *ConnectionState, packet []byte, mc uint64) ([]byte, error) {
+	dst, err := ci.dKey.DecryptDanger(b.ip[:0], packet[:header.Len], packet[header.Len:], mc, b.NB)
+	if err != nil {
+		b.bodyN = 0
+		return nil, err
+	}
+	b.bodyN = len(dst)
+	return dst, nil
+}
+
+// WireBufferAllocator hands out reusable WireBuffers for cold callers that
+// don't own a long-lived per-goroutine buffer (control plane, relay manager,
+// connection manager teardown, etc.). Hot-path goroutines hold their own
+// buffer for the life of the goroutine and don't need to acquire one.
+type WireBufferAllocator interface {
+	Acquire() *WireBuffer
+	Release(*WireBuffer)
+}
+
+// wireBufferPool is a sync.Pool-backed WireBufferAllocator. The pool is
+// keyed off a single linkMTU and prefixLen; cold callers send across the
+// data-plane mtu and target the same Device, so we size the pool's
+// buffers the same way.
+type wireBufferPool struct {
+	pool sync.Pool
+}
+
+func NewWireBufferPool(linkMTU, prefixLen int) *wireBufferPool {
+	return &wireBufferPool{
+		pool: sync.Pool{
+			New: func() any {
+				return NewWireBuffer(linkMTU, prefixLen)
+			},
+		},
+	}
+}
+
+func (p *wireBufferPool) Acquire() *WireBuffer {
+	return p.pool.Get().(*WireBuffer)
+}
+
+func (p *wireBufferPool) Release(b *WireBuffer) {
+	b.Reset()
+	p.pool.Put(b)
+}