mirror of
https://github.com/tailscale/tailscale.git
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0fb207c3d0
When a tsnet.Server dials its own Tailscale IP, TCP SYN packets are silently dropped. In inject(), outbound packets with dst=self fail the shouldSendToHost check and fall through to WireGuard, which has no peer for the node's own address. Fix this by detecting self-addressed packets in inject() using isLocalIP and delivering them back into gVisor's network stack as inbound packets via a new DeliverLoopback method on linkEndpoint. The outbound packet must be re-serialized into a new PacketBuffer because outbound packets have their headers parsed into separate views, but DeliverNetworkPacket expects raw unparsed data. Updates #18829 Signed-off-by: James Tucker <james@tailscale.com>
1369 lines
40 KiB
Go
1369 lines
40 KiB
Go
// Copyright (c) Tailscale Inc & contributors
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// SPDX-License-Identifier: BSD-3-Clause
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package netstack
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import (
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"context"
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"fmt"
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"maps"
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"net"
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"net/netip"
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"runtime"
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"testing"
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"time"
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"gvisor.dev/gvisor/pkg/buffer"
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"gvisor.dev/gvisor/pkg/tcpip"
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"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
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"gvisor.dev/gvisor/pkg/tcpip/header"
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"gvisor.dev/gvisor/pkg/tcpip/stack"
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"tailscale.com/envknob"
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"tailscale.com/ipn"
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"tailscale.com/ipn/ipnlocal"
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"tailscale.com/ipn/store/mem"
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"tailscale.com/metrics"
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"tailscale.com/net/netx"
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"tailscale.com/net/packet"
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"tailscale.com/net/tsaddr"
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"tailscale.com/net/tsdial"
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"tailscale.com/net/tstun"
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"tailscale.com/tsd"
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"tailscale.com/tstest"
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"tailscale.com/types/ipproto"
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"tailscale.com/types/logid"
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"tailscale.com/types/netmap"
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"tailscale.com/wgengine"
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"tailscale.com/wgengine/filter"
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)
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// TestInjectInboundLeak tests that injectInbound doesn't leak memory.
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// See https://github.com/tailscale/tailscale/issues/3762
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func TestInjectInboundLeak(t *testing.T) {
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tunDev := tstun.NewFake()
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dialer := new(tsdial.Dialer)
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logf := func(format string, args ...any) {
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if !t.Failed() {
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t.Logf(format, args...)
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}
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}
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sys := tsd.NewSystem()
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eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
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Tun: tunDev,
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Dialer: dialer,
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SetSubsystem: sys.Set,
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HealthTracker: sys.HealthTracker.Get(),
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Metrics: sys.UserMetricsRegistry(),
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EventBus: sys.Bus.Get(),
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})
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if err != nil {
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t.Fatal(err)
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}
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defer eng.Close()
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sys.Set(eng)
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sys.Set(new(mem.Store))
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tunWrap := sys.Tun.Get()
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lb, err := ipnlocal.NewLocalBackend(logf, logid.PublicID{}, sys, 0)
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if err != nil {
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t.Fatal(err)
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}
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t.Cleanup(lb.Shutdown)
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ns, err := Create(logf, tunWrap, eng, sys.MagicSock.Get(), dialer, sys.DNSManager.Get(), sys.ProxyMapper())
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if err != nil {
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t.Fatal(err)
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}
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defer ns.Close()
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ns.ProcessLocalIPs = true
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if err := ns.Start(lb); err != nil {
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t.Fatalf("Start: %v", err)
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}
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ns.atomicIsLocalIPFunc.Store(func(netip.Addr) bool { return true })
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pkt := &packet.Parsed{}
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const N = 10_000
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ms0 := getMemStats()
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for range N {
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outcome, _ := ns.injectInbound(pkt, tunWrap, nil)
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if outcome != filter.DropSilently {
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t.Fatalf("got outcome %v; want DropSilently", outcome)
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}
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}
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ms1 := getMemStats()
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if grew := int64(ms1.HeapObjects) - int64(ms0.HeapObjects); grew >= N {
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t.Fatalf("grew by %v (which is too much and >= the %v packets we sent)", grew, N)
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}
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}
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func getMemStats() (ms runtime.MemStats) {
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runtime.GC()
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runtime.ReadMemStats(&ms)
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return
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}
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func makeNetstack(tb testing.TB, config func(*Impl)) *Impl {
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tunDev := tstun.NewFake()
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sys := tsd.NewSystem()
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sys.Set(new(mem.Store))
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dialer := new(tsdial.Dialer)
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logf := tstest.WhileTestRunningLogger(tb)
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eng, err := wgengine.NewUserspaceEngine(logf, wgengine.Config{
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Tun: tunDev,
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Dialer: dialer,
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SetSubsystem: sys.Set,
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HealthTracker: sys.HealthTracker.Get(),
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Metrics: sys.UserMetricsRegistry(),
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EventBus: sys.Bus.Get(),
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})
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if err != nil {
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tb.Fatal(err)
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}
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tb.Cleanup(func() { eng.Close() })
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sys.Set(eng)
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ns, err := Create(logf, sys.Tun.Get(), eng, sys.MagicSock.Get(), dialer, sys.DNSManager.Get(), sys.ProxyMapper())
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if err != nil {
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tb.Fatal(err)
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}
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tb.Cleanup(func() { ns.Close() })
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sys.Set(ns)
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lb, err := ipnlocal.NewLocalBackend(logf, logid.PublicID{}, sys, 0)
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if err != nil {
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tb.Fatalf("NewLocalBackend: %v", err)
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}
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tb.Cleanup(lb.Shutdown)
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ns.atomicIsLocalIPFunc.Store(func(netip.Addr) bool { return true })
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if config != nil {
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config(ns)
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}
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if err := ns.Start(lb); err != nil {
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tb.Fatalf("Start: %v", err)
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}
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return ns
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}
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func TestShouldHandlePing(t *testing.T) {
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srcIP := netip.AddrFrom4([4]byte{1, 2, 3, 4})
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t.Run("ICMP4", func(t *testing.T) {
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dst := netip.MustParseAddr("5.6.7.8")
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icmph := packet.ICMP4Header{
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IP4Header: packet.IP4Header{
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IPProto: ipproto.ICMPv4,
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Src: srcIP,
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Dst: dst,
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},
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Type: packet.ICMP4EchoRequest,
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Code: packet.ICMP4NoCode,
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}
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_, payload := packet.ICMPEchoPayload(nil)
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icmpPing := packet.Generate(icmph, payload)
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pkt := &packet.Parsed{}
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pkt.Decode(icmpPing)
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impl := makeNetstack(t, func(impl *Impl) {
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impl.ProcessSubnets = true
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})
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pingDst, ok := impl.shouldHandlePing(pkt)
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if !ok {
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t.Errorf("expected shouldHandlePing==true")
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}
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if pingDst != dst {
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t.Errorf("got dst %s; want %s", pingDst, dst)
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}
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})
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t.Run("ICMP6-no-via", func(t *testing.T) {
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dst := netip.MustParseAddr("2a09:8280:1::4169")
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icmph := packet.ICMP6Header{
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IP6Header: packet.IP6Header{
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IPProto: ipproto.ICMPv6,
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Src: srcIP,
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Dst: dst,
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},
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Type: packet.ICMP6EchoRequest,
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Code: packet.ICMP6NoCode,
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}
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_, payload := packet.ICMPEchoPayload(nil)
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icmpPing := packet.Generate(icmph, payload)
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pkt := &packet.Parsed{}
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pkt.Decode(icmpPing)
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impl := makeNetstack(t, func(impl *Impl) {
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impl.ProcessSubnets = true
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})
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pingDst, ok := impl.shouldHandlePing(pkt)
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// Expect that we handle this since it's going out onto the
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// network.
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if !ok {
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t.Errorf("expected shouldHandlePing==true")
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}
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if pingDst != dst {
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t.Errorf("got dst %s; want %s", pingDst, dst)
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}
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})
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t.Run("ICMP6-tailscale-addr", func(t *testing.T) {
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dst := netip.MustParseAddr("fd7a:115c:a1e0:ab12::1")
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icmph := packet.ICMP6Header{
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IP6Header: packet.IP6Header{
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IPProto: ipproto.ICMPv6,
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Src: srcIP,
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Dst: dst,
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},
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Type: packet.ICMP6EchoRequest,
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Code: packet.ICMP6NoCode,
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}
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_, payload := packet.ICMPEchoPayload(nil)
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icmpPing := packet.Generate(icmph, payload)
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pkt := &packet.Parsed{}
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pkt.Decode(icmpPing)
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impl := makeNetstack(t, func(impl *Impl) {
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impl.ProcessSubnets = true
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})
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_, ok := impl.shouldHandlePing(pkt)
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// We don't handle this because it's a Tailscale IP and not 4via6
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if ok {
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t.Errorf("expected shouldHandlePing==false")
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}
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})
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// Handle pings for 4via6 addresses regardless of ProcessSubnets
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for _, subnets := range []bool{true, false} {
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t.Run("ICMP6-4via6-ProcessSubnets-"+fmt.Sprint(subnets), func(t *testing.T) {
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// The 4via6 route 10.1.1.0/24 siteid 7, and then the IP
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// 10.1.1.9 within that route.
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dst := netip.MustParseAddr("fd7a:115c:a1e0:b1a:0:7:a01:109")
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expectedPingDst := netip.MustParseAddr("10.1.1.9")
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icmph := packet.ICMP6Header{
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IP6Header: packet.IP6Header{
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IPProto: ipproto.ICMPv6,
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Src: srcIP,
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Dst: dst,
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},
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Type: packet.ICMP6EchoRequest,
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Code: packet.ICMP6NoCode,
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}
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_, payload := packet.ICMPEchoPayload(nil)
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icmpPing := packet.Generate(icmph, payload)
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pkt := &packet.Parsed{}
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pkt.Decode(icmpPing)
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impl := makeNetstack(t, func(impl *Impl) {
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impl.ProcessSubnets = subnets
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})
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pingDst, ok := impl.shouldHandlePing(pkt)
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// Handled due to being 4via6
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if !ok {
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t.Errorf("expected shouldHandlePing==true")
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} else if pingDst != expectedPingDst {
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t.Errorf("got dst %s; want %s", pingDst, expectedPingDst)
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}
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})
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}
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}
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// looksLikeATailscaleSelfAddress reports whether addr looks like
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// a Tailscale self address, for tests.
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func looksLikeATailscaleSelfAddress(addr netip.Addr) bool {
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return addr.Is4() && tsaddr.IsTailscaleIP(addr) ||
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addr.Is6() && tsaddr.Tailscale4To6Range().Contains(addr)
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}
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func TestShouldProcessInbound(t *testing.T) {
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testCases := []struct {
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name string
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pkt *packet.Parsed
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afterStart func(*Impl) // optional; after Impl.Start is called
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beforeStart func(*Impl) // optional; before Impl.Start is called
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want bool
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runOnGOOS string
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}{
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{
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name: "ipv6-via",
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pkt: &packet.Parsed{
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IPVersion: 6,
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IPProto: ipproto.TCP,
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Src: netip.MustParseAddrPort("100.101.102.103:1234"),
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// $ tailscale debug via 7 10.1.1.9/24
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// fd7a:115c:a1e0:b1a:0:7:a01:109/120
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Dst: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:7:a01:109]:5678"),
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TCPFlags: packet.TCPSyn,
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},
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afterStart: func(i *Impl) {
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prefs := ipn.NewPrefs()
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prefs.AdvertiseRoutes = []netip.Prefix{
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// $ tailscale debug via 7 10.1.1.0/24
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// fd7a:115c:a1e0:b1a:0:7:a01:100/120
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netip.MustParsePrefix("fd7a:115c:a1e0:b1a:0:7:a01:100/120"),
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}
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i.lb.Start(ipn.Options{
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UpdatePrefs: prefs,
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})
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i.atomicIsLocalIPFunc.Store(looksLikeATailscaleSelfAddress)
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},
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beforeStart: func(i *Impl) {
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// This should be handled even if we're
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// otherwise not processing local IPs or
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// subnets.
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i.ProcessLocalIPs = false
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i.ProcessSubnets = false
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},
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want: true,
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},
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{
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name: "ipv6-via-not-advertised",
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pkt: &packet.Parsed{
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IPVersion: 6,
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IPProto: ipproto.TCP,
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Src: netip.MustParseAddrPort("100.101.102.103:1234"),
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// $ tailscale debug via 7 10.1.1.9/24
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// fd7a:115c:a1e0:b1a:0:7:a01:109/120
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Dst: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:7:a01:109]:5678"),
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TCPFlags: packet.TCPSyn,
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},
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afterStart: func(i *Impl) {
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prefs := ipn.NewPrefs()
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prefs.AdvertiseRoutes = []netip.Prefix{
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// tailscale debug via 7 10.1.2.0/24
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// fd7a:115c:a1e0:b1a:0:7:a01:200/120
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netip.MustParsePrefix("fd7a:115c:a1e0:b1a:0:7:a01:200/120"),
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}
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i.lb.Start(ipn.Options{
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UpdatePrefs: prefs,
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})
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},
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want: false,
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},
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{
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name: "tailscale-ssh-enabled",
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pkt: &packet.Parsed{
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IPVersion: 4,
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IPProto: ipproto.TCP,
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Src: netip.MustParseAddrPort("100.101.102.103:1234"),
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Dst: netip.MustParseAddrPort("100.101.102.104:22"),
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TCPFlags: packet.TCPSyn,
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},
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afterStart: func(i *Impl) {
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prefs := ipn.NewPrefs()
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prefs.RunSSH = true
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i.lb.Start(ipn.Options{
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UpdatePrefs: prefs,
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})
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i.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
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return addr.String() == "100.101.102.104" // Dst, above
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})
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},
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want: true,
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runOnGOOS: "linux",
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},
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{
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name: "tailscale-ssh-disabled",
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pkt: &packet.Parsed{
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IPVersion: 4,
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IPProto: ipproto.TCP,
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Src: netip.MustParseAddrPort("100.101.102.103:1234"),
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Dst: netip.MustParseAddrPort("100.101.102.104:22"),
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TCPFlags: packet.TCPSyn,
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},
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afterStart: func(i *Impl) {
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prefs := ipn.NewPrefs()
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prefs.RunSSH = false // default, but to be explicit
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i.lb.Start(ipn.Options{
|
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UpdatePrefs: prefs,
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})
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i.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
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return addr.String() == "100.101.102.104" // Dst, above
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})
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},
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want: false,
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},
|
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{
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name: "process-local-ips",
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pkt: &packet.Parsed{
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IPVersion: 4,
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IPProto: ipproto.TCP,
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Src: netip.MustParseAddrPort("100.101.102.103:1234"),
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Dst: netip.MustParseAddrPort("100.101.102.104:4567"),
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||
TCPFlags: packet.TCPSyn,
|
||
},
|
||
afterStart: func(i *Impl) {
|
||
i.ProcessLocalIPs = true
|
||
i.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr.String() == "100.101.102.104" // Dst, above
|
||
})
|
||
},
|
||
want: true,
|
||
},
|
||
{
|
||
name: "process-subnets",
|
||
pkt: &packet.Parsed{
|
||
IPVersion: 4,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("100.101.102.103:1234"),
|
||
Dst: netip.MustParseAddrPort("10.1.2.3:4567"),
|
||
TCPFlags: packet.TCPSyn,
|
||
},
|
||
beforeStart: func(i *Impl) {
|
||
i.ProcessSubnets = true
|
||
},
|
||
afterStart: func(i *Impl) {
|
||
// For testing purposes, assume all Tailscale
|
||
// IPs are local; the Dst above is something
|
||
// not in that range.
|
||
i.atomicIsLocalIPFunc.Store(looksLikeATailscaleSelfAddress)
|
||
},
|
||
want: true,
|
||
},
|
||
{
|
||
name: "peerapi-port-subnet-router", // see #6235
|
||
pkt: &packet.Parsed{
|
||
IPVersion: 4,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("100.101.102.103:1234"),
|
||
Dst: netip.MustParseAddrPort("10.0.0.23:5555"),
|
||
TCPFlags: packet.TCPSyn,
|
||
},
|
||
beforeStart: func(i *Impl) {
|
||
// As if we were running on Linux where netstack isn't used.
|
||
i.ProcessSubnets = false
|
||
i.atomicIsLocalIPFunc.Store(func(netip.Addr) bool { return false })
|
||
},
|
||
afterStart: func(i *Impl) {
|
||
prefs := ipn.NewPrefs()
|
||
prefs.AdvertiseRoutes = []netip.Prefix{
|
||
netip.MustParsePrefix("10.0.0.1/24"),
|
||
}
|
||
i.lb.Start(ipn.Options{
|
||
UpdatePrefs: prefs,
|
||
})
|
||
|
||
// Set the PeerAPI port to the Dst port above.
|
||
i.peerapiPort4Atomic.Store(5555)
|
||
i.peerapiPort6Atomic.Store(5555)
|
||
},
|
||
want: false,
|
||
},
|
||
|
||
// TODO(andrew): test PeerAPI
|
||
// TODO(andrew): test TCP packets without the SYN flag set
|
||
}
|
||
|
||
for _, tc := range testCases {
|
||
t.Run(tc.name, func(t *testing.T) {
|
||
if tc.runOnGOOS != "" && runtime.GOOS != tc.runOnGOOS {
|
||
t.Skipf("skipping on GOOS=%v", runtime.GOOS)
|
||
}
|
||
impl := makeNetstack(t, tc.beforeStart)
|
||
if tc.afterStart != nil {
|
||
tc.afterStart(impl)
|
||
}
|
||
|
||
got := impl.shouldProcessInbound(tc.pkt, nil)
|
||
if got != tc.want {
|
||
t.Errorf("got shouldProcessInbound()=%v; want %v", got, tc.want)
|
||
} else {
|
||
t.Logf("OK: shouldProcessInbound() = %v", got)
|
||
}
|
||
})
|
||
}
|
||
}
|
||
|
||
func tcp4syn(tb testing.TB, src, dst netip.Addr, sport, dport uint16) []byte {
|
||
ip := header.IPv4(make([]byte, header.IPv4MinimumSize+header.TCPMinimumSize))
|
||
ip.Encode(&header.IPv4Fields{
|
||
Protocol: uint8(header.TCPProtocolNumber),
|
||
TotalLength: header.IPv4MinimumSize + header.TCPMinimumSize,
|
||
TTL: 64,
|
||
SrcAddr: tcpip.AddrFrom4Slice(src.AsSlice()),
|
||
DstAddr: tcpip.AddrFrom4Slice(dst.AsSlice()),
|
||
})
|
||
ip.SetChecksum(^ip.CalculateChecksum())
|
||
if !ip.IsChecksumValid() {
|
||
tb.Fatal("test broken; packet has incorrect IP checksum")
|
||
}
|
||
|
||
tcp := header.TCP(ip[header.IPv4MinimumSize:])
|
||
tcp.Encode(&header.TCPFields{
|
||
SrcPort: sport,
|
||
DstPort: dport,
|
||
SeqNum: 0,
|
||
DataOffset: header.TCPMinimumSize,
|
||
Flags: header.TCPFlagSyn,
|
||
WindowSize: 65535,
|
||
Checksum: 0,
|
||
})
|
||
xsum := header.PseudoHeaderChecksum(
|
||
header.TCPProtocolNumber,
|
||
tcpip.AddrFrom4Slice(src.AsSlice()),
|
||
tcpip.AddrFrom4Slice(dst.AsSlice()),
|
||
uint16(header.TCPMinimumSize),
|
||
)
|
||
tcp.SetChecksum(^tcp.CalculateChecksum(xsum))
|
||
if !tcp.IsChecksumValid(tcpip.AddrFrom4Slice(src.AsSlice()), tcpip.AddrFrom4Slice(dst.AsSlice()), 0, 0) {
|
||
tb.Fatal("test broken; packet has incorrect TCP checksum")
|
||
}
|
||
|
||
return ip
|
||
}
|
||
|
||
// makeHangDialer returns a dialer that notifies the returned channel when a
|
||
// connection is dialed and then hangs until the test finishes.
|
||
func makeHangDialer(tb testing.TB) (netx.DialFunc, chan struct{}) {
|
||
done := make(chan struct{})
|
||
tb.Cleanup(func() {
|
||
close(done)
|
||
})
|
||
|
||
gotConn := make(chan struct{}, 1)
|
||
fn := func(ctx context.Context, network, address string) (net.Conn, error) {
|
||
// Signal that we have a new connection
|
||
tb.Logf("hangDialer: called with network=%q address=%q", network, address)
|
||
select {
|
||
case gotConn <- struct{}{}:
|
||
default:
|
||
}
|
||
|
||
// Hang until the test is done.
|
||
select {
|
||
case <-ctx.Done():
|
||
tb.Logf("context done")
|
||
case <-done:
|
||
tb.Logf("function completed")
|
||
}
|
||
return nil, fmt.Errorf("canceled")
|
||
}
|
||
return fn, gotConn
|
||
}
|
||
|
||
// TestTCPForwardLimits verifies that the limits on the TCP forwarder work in a
|
||
// success case (i.e. when we don't hit the limit).
|
||
func TestTCPForwardLimits(t *testing.T) {
|
||
envknob.Setenv("TS_DEBUG_NETSTACK", "true")
|
||
impl := makeNetstack(t, func(impl *Impl) {
|
||
impl.ProcessSubnets = true
|
||
})
|
||
|
||
dialFn, gotConn := makeHangDialer(t)
|
||
impl.forwardDialFunc = dialFn
|
||
|
||
prefs := ipn.NewPrefs()
|
||
prefs.AdvertiseRoutes = []netip.Prefix{
|
||
// This is the TEST-NET-1 IP block for use in documentation,
|
||
// and should never actually be routable.
|
||
netip.MustParsePrefix("192.0.2.0/24"),
|
||
}
|
||
impl.lb.Start(ipn.Options{
|
||
UpdatePrefs: prefs,
|
||
})
|
||
impl.atomicIsLocalIPFunc.Store(looksLikeATailscaleSelfAddress)
|
||
|
||
// Inject an "outbound" packet that's going to an IP address that times
|
||
// out. We need to re-parse from a byte slice so that the internal
|
||
// buffer in the packet.Parsed type is filled out.
|
||
client := netip.MustParseAddr("100.101.102.103")
|
||
destAddr := netip.MustParseAddr("192.0.2.1")
|
||
pkt := tcp4syn(t, client, destAddr, 1234, 4567)
|
||
var parsed packet.Parsed
|
||
parsed.Decode(pkt)
|
||
|
||
// When injecting this packet, we want the outcome to be "drop
|
||
// silently", which indicates that netstack is processing the
|
||
// packet and not delivering it to the host system.
|
||
if resp, _ := impl.injectInbound(&parsed, impl.tundev, nil); resp != filter.DropSilently {
|
||
t.Errorf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
|
||
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
|
||
defer cancel()
|
||
|
||
// Wait until we have an in-flight outgoing connection.
|
||
select {
|
||
case <-ctx.Done():
|
||
t.Fatalf("timed out waiting for connection")
|
||
case <-gotConn:
|
||
t.Logf("got connection in progress")
|
||
}
|
||
|
||
// Inject another packet, which will be deduplicated and thus not
|
||
// increment our counter.
|
||
parsed.Decode(pkt)
|
||
if resp, _ := impl.injectInbound(&parsed, impl.tundev, nil); resp != filter.DropSilently {
|
||
t.Errorf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
|
||
// Verify that we now have a single in-flight address in our map.
|
||
impl.mu.Lock()
|
||
inFlight := maps.Clone(impl.connsInFlightByClient)
|
||
impl.mu.Unlock()
|
||
|
||
if got, ok := inFlight[client]; !ok || got != 1 {
|
||
t.Errorf("expected 1 in-flight connection for %v, got: %v", client, inFlight)
|
||
}
|
||
|
||
// Get the expvar statistics and verify that we're exporting the
|
||
// correct metric.
|
||
metrics := impl.ExpVar().(*metrics.Set)
|
||
|
||
const metricName = "gauge_tcp_forward_in_flight"
|
||
if v := metrics.Get(metricName).String(); v != "1" {
|
||
t.Errorf("got metric %q=%s, want 1", metricName, v)
|
||
}
|
||
}
|
||
|
||
// TestTCPForwardLimits_PerClient verifies that the per-client limit for TCP
|
||
// forwarding works.
|
||
func TestTCPForwardLimits_PerClient(t *testing.T) {
|
||
envknob.Setenv("TS_DEBUG_NETSTACK", "true")
|
||
|
||
// Set our test override limits during this test.
|
||
tstest.Replace(t, &maxInFlightConnectionAttemptsForTest, 2)
|
||
tstest.Replace(t, &maxInFlightConnectionAttemptsPerClientForTest, 1)
|
||
|
||
impl := makeNetstack(t, func(impl *Impl) {
|
||
impl.ProcessSubnets = true
|
||
})
|
||
|
||
dialFn, gotConn := makeHangDialer(t)
|
||
impl.forwardDialFunc = dialFn
|
||
|
||
prefs := ipn.NewPrefs()
|
||
prefs.AdvertiseRoutes = []netip.Prefix{
|
||
// This is the TEST-NET-1 IP block for use in documentation,
|
||
// and should never actually be routable.
|
||
netip.MustParsePrefix("192.0.2.0/24"),
|
||
}
|
||
impl.lb.Start(ipn.Options{
|
||
UpdatePrefs: prefs,
|
||
})
|
||
impl.atomicIsLocalIPFunc.Store(looksLikeATailscaleSelfAddress)
|
||
|
||
// Inject an "outbound" packet that's going to an IP address that times
|
||
// out. We need to re-parse from a byte slice so that the internal
|
||
// buffer in the packet.Parsed type is filled out.
|
||
client := netip.MustParseAddr("100.101.102.103")
|
||
destAddr := netip.MustParseAddr("192.0.2.1")
|
||
|
||
// Helpers
|
||
var port uint16 = 1234
|
||
mustInjectPacket := func() {
|
||
pkt := tcp4syn(t, client, destAddr, port, 4567)
|
||
port++ // to avoid deduplication based on endpoint
|
||
|
||
var parsed packet.Parsed
|
||
parsed.Decode(pkt)
|
||
|
||
// When injecting this packet, we want the outcome to be "drop
|
||
// silently", which indicates that netstack is processing the
|
||
// packet and not delivering it to the host system.
|
||
if resp, _ := impl.injectInbound(&parsed, impl.tundev, nil); resp != filter.DropSilently {
|
||
t.Fatalf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
}
|
||
|
||
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
|
||
defer cancel()
|
||
|
||
waitPacket := func() {
|
||
select {
|
||
case <-ctx.Done():
|
||
t.Fatalf("timed out waiting for connection")
|
||
case <-gotConn:
|
||
t.Logf("got connection in progress")
|
||
}
|
||
}
|
||
|
||
// Inject the packet to start the TCP forward and wait until we have an
|
||
// in-flight outgoing connection.
|
||
mustInjectPacket()
|
||
waitPacket()
|
||
|
||
// Verify that we now have a single in-flight address in our map.
|
||
impl.mu.Lock()
|
||
inFlight := maps.Clone(impl.connsInFlightByClient)
|
||
impl.mu.Unlock()
|
||
|
||
if got, ok := inFlight[client]; !ok || got != 1 {
|
||
t.Errorf("expected 1 in-flight connection for %v, got: %v", client, inFlight)
|
||
}
|
||
|
||
metrics := impl.ExpVar().(*metrics.Set)
|
||
|
||
// One client should have reached the limit at this point.
|
||
if v := metrics.Get("gauge_tcp_forward_in_flight_per_client_limit_reached").String(); v != "1" {
|
||
t.Errorf("got limit reached expvar metric=%s, want 1", v)
|
||
}
|
||
|
||
// Inject another packet, and verify that we've incremented our
|
||
// "dropped" metrics since this will have been dropped.
|
||
mustInjectPacket()
|
||
|
||
// expvar metric
|
||
const metricName = "counter_tcp_forward_max_in_flight_per_client_drop"
|
||
if v := metrics.Get(metricName).String(); v != "1" {
|
||
t.Errorf("got expvar metric %q=%s, want 1", metricName, v)
|
||
}
|
||
|
||
// client metric
|
||
if v := metricPerClientForwardLimit.Value(); v != 1 {
|
||
t.Errorf("got clientmetric limit metric=%d, want 1", v)
|
||
}
|
||
}
|
||
|
||
// TestHandleLocalPackets tests the handleLocalPackets function, ensuring that
|
||
// we are properly deciding to handle packets that are destined for "local"
|
||
// IPs–addresses that are either for this node, or that it is responsible for.
|
||
//
|
||
// See, e.g. #11304
|
||
func TestHandleLocalPackets(t *testing.T) {
|
||
var (
|
||
selfIP4 = netip.MustParseAddr("100.64.1.2")
|
||
selfIP6 = netip.MustParseAddr("fd7a:115c:a1e0::123")
|
||
)
|
||
|
||
impl := makeNetstack(t, func(impl *Impl) {
|
||
impl.ProcessSubnets = false
|
||
impl.ProcessLocalIPs = false
|
||
impl.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr == selfIP4 || addr == selfIP6
|
||
})
|
||
})
|
||
|
||
prefs := ipn.NewPrefs()
|
||
prefs.AdvertiseRoutes = []netip.Prefix{
|
||
// $ tailscale debug via 7 10.1.1.0/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:100/120
|
||
netip.MustParsePrefix("fd7a:115c:a1e0:b1a:0:7:a01:100/120"),
|
||
}
|
||
prefs.AdvertiseServices = []string{"svc:test-service"}
|
||
_, err := impl.lb.EditPrefs(&ipn.MaskedPrefs{
|
||
Prefs: *prefs,
|
||
AdvertiseRoutesSet: true,
|
||
AdvertiseServicesSet: true,
|
||
})
|
||
if err != nil {
|
||
t.Fatalf("EditPrefs: %v", err)
|
||
}
|
||
IPServiceMap := netmap.IPServiceMappings{
|
||
netip.MustParseAddr("100.99.55.111"): "svc:test-service",
|
||
netip.MustParseAddr("fd7a:115c:a1e0::abcd"): "svc:test-service",
|
||
}
|
||
impl.lb.SetIPServiceMappingsForTest(IPServiceMap)
|
||
|
||
t.Run("ShouldHandleServiceIP", func(t *testing.T) {
|
||
pkt := &packet.Parsed{
|
||
IPVersion: 4,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("127.0.0.1:9999"),
|
||
Dst: netip.MustParseAddrPort("100.100.100.100:53"),
|
||
TCPFlags: packet.TCPSyn,
|
||
}
|
||
resp, _ := impl.handleLocalPackets(pkt, impl.tundev, nil)
|
||
if resp != filter.DropSilently {
|
||
t.Errorf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
})
|
||
t.Run("ShouldHandle4via6", func(t *testing.T) {
|
||
pkt := &packet.Parsed{
|
||
IPVersion: 6,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("[::1]:1234"),
|
||
|
||
// This is an IP in the above 4via6 subnet that this node handles.
|
||
// $ tailscale debug via 7 10.1.1.9/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:109/120
|
||
Dst: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:7:a01:109]:5678"),
|
||
TCPFlags: packet.TCPSyn,
|
||
}
|
||
resp, _ := impl.handleLocalPackets(pkt, impl.tundev, nil)
|
||
|
||
// DropSilently is the outcome we expected, since we actually
|
||
// handled this packet by injecting it into netstack, which
|
||
// will handle creating the TCP forwarder. We drop it so we
|
||
// don't process the packet outside of netstack.
|
||
if resp != filter.DropSilently {
|
||
t.Errorf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
})
|
||
t.Run("ShouldHandleLocalTailscaleServices", func(t *testing.T) {
|
||
pkt := &packet.Parsed{
|
||
IPVersion: 4,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("127.0.0.1:9999"),
|
||
Dst: netip.MustParseAddrPort("100.99.55.111:80"),
|
||
TCPFlags: packet.TCPSyn,
|
||
}
|
||
resp, _ := impl.handleLocalPackets(pkt, impl.tundev, nil)
|
||
if resp != filter.DropSilently {
|
||
t.Errorf("got filter outcome %v, want filter.DropSilently", resp)
|
||
}
|
||
})
|
||
t.Run("OtherNonHandled", func(t *testing.T) {
|
||
pkt := &packet.Parsed{
|
||
IPVersion: 6,
|
||
IPProto: ipproto.TCP,
|
||
Src: netip.MustParseAddrPort("[::1]:1234"),
|
||
|
||
// This IP is *not* in the above 4via6 route
|
||
// $ tailscale debug via 99 10.1.1.9/24
|
||
// fd7a:115c:a1e0:b1a:0:63:a01:109/120
|
||
Dst: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:63:a01:109]:5678"),
|
||
TCPFlags: packet.TCPSyn,
|
||
}
|
||
resp, _ := impl.handleLocalPackets(pkt, impl.tundev, nil)
|
||
|
||
// Accept means that handleLocalPackets does not handle this
|
||
// packet, we "accept" it to continue further processing,
|
||
// instead of dropping because it was already handled.
|
||
if resp != filter.Accept {
|
||
t.Errorf("got filter outcome %v, want filter.Accept", resp)
|
||
}
|
||
})
|
||
}
|
||
|
||
func TestShouldSendToHost(t *testing.T) {
|
||
var (
|
||
selfIP4 = netip.MustParseAddr("100.64.1.2")
|
||
selfIP6 = netip.MustParseAddr("fd7a:115c:a1e0::123")
|
||
tailscaleServiceIP4 = netip.MustParseAddr("100.99.55.111")
|
||
tailscaleServiceIP6 = netip.MustParseAddr("fd7a:115c:a1e0::abcd")
|
||
)
|
||
|
||
makeTestNetstack := func(tb testing.TB) *Impl {
|
||
impl := makeNetstack(tb, func(impl *Impl) {
|
||
impl.ProcessSubnets = false
|
||
impl.ProcessLocalIPs = false
|
||
impl.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr == selfIP4 || addr == selfIP6
|
||
})
|
||
impl.atomicIsVIPServiceIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr == tailscaleServiceIP4 || addr == tailscaleServiceIP6
|
||
})
|
||
})
|
||
|
||
prefs := ipn.NewPrefs()
|
||
prefs.AdvertiseRoutes = []netip.Prefix{
|
||
// $ tailscale debug via 7 10.1.1.0/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:100/120
|
||
netip.MustParsePrefix("fd7a:115c:a1e0:b1a:0:7:a01:100/120"),
|
||
}
|
||
_, err := impl.lb.EditPrefs(&ipn.MaskedPrefs{
|
||
Prefs: *prefs,
|
||
AdvertiseRoutesSet: true,
|
||
})
|
||
if err != nil {
|
||
tb.Fatalf("EditPrefs: %v", err)
|
||
}
|
||
return impl
|
||
}
|
||
|
||
testCases := []struct {
|
||
name string
|
||
src, dst netip.AddrPort
|
||
want bool
|
||
}{
|
||
// Reply from service IP to localhost should be sent to host,
|
||
// not over WireGuard.
|
||
{
|
||
name: "from_service_ip_to_localhost",
|
||
src: netip.AddrPortFrom(serviceIP, 53),
|
||
dst: netip.MustParseAddrPort("127.0.0.1:9999"),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "from_service_ip_to_localhost_v6",
|
||
src: netip.AddrPortFrom(serviceIPv6, 53),
|
||
dst: netip.MustParseAddrPort("[::1]:9999"),
|
||
want: true,
|
||
},
|
||
// A reply from the local IP to a remote host isn't sent to the
|
||
// host, but rather over WireGuard.
|
||
{
|
||
name: "local_ip_to_remote",
|
||
src: netip.AddrPortFrom(selfIP4, 12345),
|
||
dst: netip.MustParseAddrPort("100.64.99.88:7777"),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "local_ip_to_remote_v6",
|
||
src: netip.AddrPortFrom(selfIP6, 12345),
|
||
dst: netip.MustParseAddrPort("[fd7a:115:a1e0::99]:7777"),
|
||
want: false,
|
||
},
|
||
// A reply from a 4via6 address to a remote host isn't sent to
|
||
// the local host, but rather over WireGuard. See:
|
||
// https://github.com/tailscale/tailscale/issues/12448
|
||
{
|
||
name: "4via6_to_remote",
|
||
|
||
// $ tailscale debug via 7 10.1.1.99/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:163/120
|
||
src: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:7:a01:163]:12345"),
|
||
dst: netip.MustParseAddrPort("[fd7a:115:a1e0::99]:7777"),
|
||
want: false,
|
||
},
|
||
// However, a reply from a 4via6 address to the local Tailscale
|
||
// IP for this host *is* sent to the local host. See:
|
||
// https://github.com/tailscale/tailscale/issues/11304
|
||
{
|
||
name: "4via6_to_local",
|
||
|
||
// $ tailscale debug via 7 10.1.1.99/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:163/120
|
||
src: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:7:a01:163]:12345"),
|
||
dst: netip.AddrPortFrom(selfIP6, 7777),
|
||
want: true,
|
||
},
|
||
// Traffic from a 4via6 address that we're not handling to
|
||
// either the local Tailscale IP or a remote host is sent
|
||
// outbound.
|
||
//
|
||
// In most cases, we won't see this type of traffic in the
|
||
// shouldSendToHost function, but let's confirm.
|
||
{
|
||
name: "other_4via6_to_local",
|
||
|
||
// $ tailscale debug via 4444 10.1.1.88/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:163/120
|
||
src: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:115c:a01:158]:12345"),
|
||
dst: netip.AddrPortFrom(selfIP6, 7777),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "other_4via6_to_remote",
|
||
|
||
// $ tailscale debug via 4444 10.1.1.88/24
|
||
// fd7a:115c:a1e0:b1a:0:7:a01:163/120
|
||
src: netip.MustParseAddrPort("[fd7a:115c:a1e0:b1a:0:115c:a01:158]:12345"),
|
||
dst: netip.MustParseAddrPort("[fd7a:115:a1e0::99]:7777"),
|
||
want: false,
|
||
},
|
||
// After accessing the Tailscale service from host, replies from Tailscale Service IPs
|
||
// to the local Tailscale IPs should be sent to the host.
|
||
{
|
||
name: "from_service_ip_to_local_ip",
|
||
src: netip.AddrPortFrom(tailscaleServiceIP4, 80),
|
||
dst: netip.AddrPortFrom(selfIP4, 12345),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "from_service_ip_to_local_ip_v6",
|
||
src: netip.AddrPortFrom(tailscaleServiceIP6, 80),
|
||
dst: netip.AddrPortFrom(selfIP6, 12345),
|
||
want: true,
|
||
},
|
||
// Traffic from remote IPs to Tailscale Service IPs should be sent over WireGuard.
|
||
{
|
||
name: "from_service_ip_to_remote",
|
||
src: netip.AddrPortFrom(tailscaleServiceIP4, 80),
|
||
dst: netip.MustParseAddrPort("173.201.32.56:54321"),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "from_service_ip_to_remote_v6",
|
||
src: netip.AddrPortFrom(tailscaleServiceIP6, 80),
|
||
dst: netip.MustParseAddrPort("[2001:4860:4860::8888]:54321"),
|
||
want: false,
|
||
},
|
||
}
|
||
|
||
for _, tt := range testCases {
|
||
t.Run(tt.name, func(t *testing.T) {
|
||
var pkt *stack.PacketBuffer
|
||
if tt.src.Addr().Is4() {
|
||
pkt = makeUDP4PacketBuffer(tt.src, tt.dst)
|
||
} else {
|
||
pkt = makeUDP6PacketBuffer(tt.src, tt.dst)
|
||
}
|
||
|
||
ns := makeTestNetstack(t)
|
||
if got := ns.shouldSendToHost(pkt); got != tt.want {
|
||
t.Errorf("shouldSendToHost returned %v, want %v", got, tt.want)
|
||
}
|
||
})
|
||
}
|
||
}
|
||
|
||
func makeUDP4PacketBuffer(src, dst netip.AddrPort) *stack.PacketBuffer {
|
||
if !src.Addr().Is4() || !dst.Addr().Is4() {
|
||
panic("src and dst must be IPv4")
|
||
}
|
||
|
||
data := []byte("hello world\n")
|
||
|
||
packetLen := header.IPv4MinimumSize + header.UDPMinimumSize
|
||
pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
|
||
ReserveHeaderBytes: packetLen,
|
||
Payload: buffer.MakeWithData(data),
|
||
})
|
||
|
||
// Initialize the UDP header.
|
||
udp := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
|
||
pkt.TransportProtocolNumber = header.UDPProtocolNumber
|
||
|
||
length := uint16(pkt.Size())
|
||
udp.Encode(&header.UDPFields{
|
||
SrcPort: src.Port(),
|
||
DstPort: dst.Port(),
|
||
Length: length,
|
||
})
|
||
|
||
// Add IP header
|
||
ipHdr := header.IPv4(pkt.NetworkHeader().Push(header.IPv4MinimumSize))
|
||
pkt.NetworkProtocolNumber = header.IPv4ProtocolNumber
|
||
ipHdr.Encode(&header.IPv4Fields{
|
||
TotalLength: uint16(packetLen),
|
||
Protocol: uint8(header.UDPProtocolNumber),
|
||
SrcAddr: tcpip.AddrFrom4(src.Addr().As4()),
|
||
DstAddr: tcpip.AddrFrom4(dst.Addr().As4()),
|
||
Checksum: 0,
|
||
})
|
||
|
||
return pkt
|
||
}
|
||
|
||
func makeUDP6PacketBuffer(src, dst netip.AddrPort) *stack.PacketBuffer {
|
||
if !src.Addr().Is6() || !dst.Addr().Is6() {
|
||
panic("src and dst must be IPv6")
|
||
}
|
||
data := []byte("hello world\n")
|
||
|
||
packetLen := header.IPv6MinimumSize + header.UDPMinimumSize
|
||
pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
|
||
ReserveHeaderBytes: packetLen,
|
||
Payload: buffer.MakeWithData(data),
|
||
})
|
||
|
||
srcAddr := tcpip.AddrFrom16(src.Addr().As16())
|
||
dstAddr := tcpip.AddrFrom16(dst.Addr().As16())
|
||
|
||
// Add IP header
|
||
ipHdr := header.IPv6(pkt.NetworkHeader().Push(header.IPv6MinimumSize))
|
||
pkt.NetworkProtocolNumber = header.IPv6ProtocolNumber
|
||
ipHdr.Encode(&header.IPv6Fields{
|
||
SrcAddr: srcAddr,
|
||
DstAddr: dstAddr,
|
||
PayloadLength: uint16(header.UDPMinimumSize + len(data)),
|
||
TransportProtocol: header.UDPProtocolNumber,
|
||
HopLimit: 64,
|
||
})
|
||
|
||
// Initialize the UDP header.
|
||
udp := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
|
||
pkt.TransportProtocolNumber = header.UDPProtocolNumber
|
||
|
||
length := uint16(pkt.Size())
|
||
udp.Encode(&header.UDPFields{
|
||
SrcPort: src.Port(),
|
||
DstPort: dst.Port(),
|
||
Length: length,
|
||
})
|
||
|
||
// Calculate the UDP pseudo-header checksum.
|
||
xsum := header.PseudoHeaderChecksum(header.UDPProtocolNumber, srcAddr, dstAddr, uint16(len(udp)))
|
||
udp.SetChecksum(^udp.CalculateChecksum(xsum))
|
||
|
||
return pkt
|
||
}
|
||
|
||
// TestIsSelfDst verifies that isSelfDst correctly identifies packets whose
|
||
// destination IP is a local Tailscale IP assigned to this node.
|
||
func TestIsSelfDst(t *testing.T) {
|
||
var (
|
||
selfIP4 = netip.MustParseAddr("100.64.1.2")
|
||
selfIP6 = netip.MustParseAddr("fd7a:115c:a1e0::123")
|
||
remoteIP4 = netip.MustParseAddr("100.64.99.88")
|
||
remoteIP6 = netip.MustParseAddr("fd7a:115c:a1e0::99")
|
||
)
|
||
|
||
ns := makeNetstack(t, func(impl *Impl) {
|
||
impl.ProcessLocalIPs = true
|
||
impl.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr == selfIP4 || addr == selfIP6
|
||
})
|
||
})
|
||
|
||
testCases := []struct {
|
||
name string
|
||
src, dst netip.AddrPort
|
||
want bool
|
||
}{
|
||
{
|
||
name: "self_to_self_v4",
|
||
src: netip.AddrPortFrom(selfIP4, 12345),
|
||
dst: netip.AddrPortFrom(selfIP4, 8081),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "self_to_self_v6",
|
||
src: netip.AddrPortFrom(selfIP6, 12345),
|
||
dst: netip.AddrPortFrom(selfIP6, 8081),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "remote_to_self_v4",
|
||
src: netip.AddrPortFrom(remoteIP4, 12345),
|
||
dst: netip.AddrPortFrom(selfIP4, 8081),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "remote_to_self_v6",
|
||
src: netip.AddrPortFrom(remoteIP6, 12345),
|
||
dst: netip.AddrPortFrom(selfIP6, 8081),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "self_to_remote_v4",
|
||
src: netip.AddrPortFrom(selfIP4, 12345),
|
||
dst: netip.AddrPortFrom(remoteIP4, 8081),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "self_to_remote_v6",
|
||
src: netip.AddrPortFrom(selfIP6, 12345),
|
||
dst: netip.AddrPortFrom(remoteIP6, 8081),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "remote_to_remote_v4",
|
||
src: netip.AddrPortFrom(remoteIP4, 12345),
|
||
dst: netip.MustParseAddrPort("100.64.77.66:7777"),
|
||
want: false,
|
||
},
|
||
{
|
||
name: "service_ip_to_self_v4",
|
||
src: netip.AddrPortFrom(serviceIP, 53),
|
||
dst: netip.AddrPortFrom(selfIP4, 9999),
|
||
want: true,
|
||
},
|
||
{
|
||
name: "service_ip_to_self_v6",
|
||
src: netip.AddrPortFrom(serviceIPv6, 53),
|
||
dst: netip.AddrPortFrom(selfIP6, 9999),
|
||
want: true,
|
||
},
|
||
}
|
||
|
||
for _, tt := range testCases {
|
||
t.Run(tt.name, func(t *testing.T) {
|
||
var pkt *stack.PacketBuffer
|
||
if tt.src.Addr().Is4() {
|
||
pkt = makeUDP4PacketBuffer(tt.src, tt.dst)
|
||
} else {
|
||
pkt = makeUDP6PacketBuffer(tt.src, tt.dst)
|
||
}
|
||
defer pkt.DecRef()
|
||
|
||
if got := ns.isSelfDst(pkt); got != tt.want {
|
||
t.Errorf("isSelfDst(%v -> %v) = %v, want %v", tt.src, tt.dst, got, tt.want)
|
||
}
|
||
})
|
||
}
|
||
}
|
||
|
||
// TestDeliverLoopback verifies that DeliverLoopback correctly re-serializes an
|
||
// outbound packet and delivers it back into gVisor's inbound path.
|
||
func TestDeliverLoopback(t *testing.T) {
|
||
ep := newLinkEndpoint(64, 1280, "", groNotSupported)
|
||
|
||
// Track delivered packets via a mock dispatcher.
|
||
type delivered struct {
|
||
proto tcpip.NetworkProtocolNumber
|
||
data []byte
|
||
}
|
||
deliveredCh := make(chan delivered, 4)
|
||
ep.Attach(&mockDispatcher{
|
||
onDeliverNetworkPacket: func(proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
|
||
// Capture the raw bytes from the delivered packet. At this
|
||
// point the packet is unparsed — everything is in the
|
||
// payload, no headers have been consumed yet.
|
||
buf := pkt.ToBuffer()
|
||
raw := buf.Flatten()
|
||
deliveredCh <- delivered{proto: proto, data: raw}
|
||
},
|
||
})
|
||
|
||
t.Run("ipv4", func(t *testing.T) {
|
||
selfAddr := netip.MustParseAddrPort("100.64.1.2:8081")
|
||
pkt := makeUDP4PacketBuffer(selfAddr, selfAddr)
|
||
// Capture what the outbound bytes look like before loopback.
|
||
wantLen := pkt.Size()
|
||
wantProto := pkt.NetworkProtocolNumber
|
||
|
||
if !ep.DeliverLoopback(pkt) {
|
||
t.Fatal("DeliverLoopback returned false")
|
||
}
|
||
|
||
select {
|
||
case got := <-deliveredCh:
|
||
if got.proto != wantProto {
|
||
t.Errorf("proto = %d, want %d", got.proto, wantProto)
|
||
}
|
||
if len(got.data) != wantLen {
|
||
t.Errorf("data length = %d, want %d", len(got.data), wantLen)
|
||
}
|
||
case <-time.After(time.Second):
|
||
t.Fatal("timeout waiting for loopback delivery")
|
||
}
|
||
})
|
||
|
||
t.Run("ipv6", func(t *testing.T) {
|
||
selfAddr := netip.MustParseAddrPort("[fd7a:115c:a1e0::123]:8081")
|
||
pkt := makeUDP6PacketBuffer(selfAddr, selfAddr)
|
||
wantLen := pkt.Size()
|
||
wantProto := pkt.NetworkProtocolNumber
|
||
|
||
if !ep.DeliverLoopback(pkt) {
|
||
t.Fatal("DeliverLoopback returned false")
|
||
}
|
||
|
||
select {
|
||
case got := <-deliveredCh:
|
||
if got.proto != wantProto {
|
||
t.Errorf("proto = %d, want %d", got.proto, wantProto)
|
||
}
|
||
if len(got.data) != wantLen {
|
||
t.Errorf("data length = %d, want %d", len(got.data), wantLen)
|
||
}
|
||
case <-time.After(time.Second):
|
||
t.Fatal("timeout waiting for loopback delivery")
|
||
}
|
||
})
|
||
|
||
t.Run("nil_dispatcher", func(t *testing.T) {
|
||
ep2 := newLinkEndpoint(64, 1280, "", groNotSupported)
|
||
// Don't attach a dispatcher.
|
||
selfAddr := netip.MustParseAddrPort("100.64.1.2:8081")
|
||
pkt := makeUDP4PacketBuffer(selfAddr, selfAddr)
|
||
if ep2.DeliverLoopback(pkt) {
|
||
t.Error("DeliverLoopback should return false with nil dispatcher")
|
||
}
|
||
// pkt refcount was consumed by DeliverLoopback, so we don't DecRef.
|
||
})
|
||
}
|
||
|
||
// mockDispatcher implements stack.NetworkDispatcher for testing.
|
||
type mockDispatcher struct {
|
||
onDeliverNetworkPacket func(tcpip.NetworkProtocolNumber, *stack.PacketBuffer)
|
||
}
|
||
|
||
func (d *mockDispatcher) DeliverNetworkPacket(proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
|
||
if d.onDeliverNetworkPacket != nil {
|
||
d.onDeliverNetworkPacket(proto, pkt)
|
||
}
|
||
}
|
||
|
||
func (d *mockDispatcher) DeliverLinkPacket(tcpip.NetworkProtocolNumber, *stack.PacketBuffer) {}
|
||
|
||
// udp4raw constructs a valid raw IPv4+UDP packet with proper checksums.
|
||
func udp4raw(t testing.TB, src, dst netip.Addr, sport, dport uint16, payload []byte) []byte {
|
||
t.Helper()
|
||
totalLen := header.IPv4MinimumSize + header.UDPMinimumSize + len(payload)
|
||
buf := make([]byte, totalLen)
|
||
|
||
ip := header.IPv4(buf)
|
||
ip.Encode(&header.IPv4Fields{
|
||
TotalLength: uint16(totalLen),
|
||
Protocol: uint8(header.UDPProtocolNumber),
|
||
TTL: 64,
|
||
SrcAddr: tcpip.AddrFrom4Slice(src.AsSlice()),
|
||
DstAddr: tcpip.AddrFrom4Slice(dst.AsSlice()),
|
||
})
|
||
ip.SetChecksum(^ip.CalculateChecksum())
|
||
|
||
// Build UDP header + payload.
|
||
u := header.UDP(buf[header.IPv4MinimumSize:])
|
||
u.Encode(&header.UDPFields{
|
||
SrcPort: sport,
|
||
DstPort: dport,
|
||
Length: uint16(header.UDPMinimumSize + len(payload)),
|
||
})
|
||
copy(buf[header.IPv4MinimumSize+header.UDPMinimumSize:], payload)
|
||
|
||
xsum := header.PseudoHeaderChecksum(
|
||
header.UDPProtocolNumber,
|
||
tcpip.AddrFrom4Slice(src.AsSlice()),
|
||
tcpip.AddrFrom4Slice(dst.AsSlice()),
|
||
uint16(header.UDPMinimumSize+len(payload)),
|
||
)
|
||
u.SetChecksum(^header.UDP(buf[header.IPv4MinimumSize:]).CalculateChecksum(xsum))
|
||
return buf
|
||
}
|
||
|
||
// TestInjectLoopback verifies that the inject goroutine delivers self-addressed
|
||
// packets back into gVisor (via DeliverLoopback) instead of sending them to
|
||
// WireGuard outbound. This is a regression test for a bug where self-dial
|
||
// packets were sent to WireGuard and silently dropped.
|
||
func TestInjectLoopback(t *testing.T) {
|
||
selfIP4 := netip.MustParseAddr("100.64.1.2")
|
||
|
||
ns := makeNetstack(t, func(impl *Impl) {
|
||
impl.ProcessLocalIPs = true
|
||
impl.atomicIsLocalIPFunc.Store(func(addr netip.Addr) bool {
|
||
return addr == selfIP4
|
||
})
|
||
})
|
||
|
||
// Register gVisor's NIC address so the stack accepts and routes
|
||
// packets for this IP.
|
||
protocolAddr := tcpip.ProtocolAddress{
|
||
Protocol: header.IPv4ProtocolNumber,
|
||
AddressWithPrefix: tcpip.AddrFrom4(selfIP4.As4()).WithPrefix(),
|
||
}
|
||
if err := ns.ipstack.AddProtocolAddress(nicID, protocolAddr, stack.AddressProperties{}); err != nil {
|
||
t.Fatalf("AddProtocolAddress: %v", err)
|
||
}
|
||
|
||
// Bind a UDP socket on the gVisor stack to receive the loopback packet.
|
||
pc, err := gonet.DialUDP(ns.ipstack, &tcpip.FullAddress{
|
||
NIC: nicID,
|
||
Addr: tcpip.AddrFrom4(selfIP4.As4()),
|
||
Port: 8081,
|
||
}, nil, header.IPv4ProtocolNumber)
|
||
if err != nil {
|
||
t.Fatalf("DialUDP: %v", err)
|
||
}
|
||
defer pc.Close()
|
||
|
||
// Build a valid self-addressed UDP packet from raw bytes and wrap it
|
||
// in a gVisor PacketBuffer with headers already pushed, as gVisor's
|
||
// outbound path produces.
|
||
payload := []byte("loopback test")
|
||
raw := udp4raw(t, selfIP4, selfIP4, 12345, 8081, payload)
|
||
|
||
pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
|
||
ReserveHeaderBytes: header.IPv4MinimumSize + header.UDPMinimumSize,
|
||
Payload: buffer.MakeWithData(payload),
|
||
})
|
||
copy(pkt.TransportHeader().Push(header.UDPMinimumSize),
|
||
raw[header.IPv4MinimumSize:header.IPv4MinimumSize+header.UDPMinimumSize])
|
||
pkt.TransportProtocolNumber = header.UDPProtocolNumber
|
||
copy(pkt.NetworkHeader().Push(header.IPv4MinimumSize), raw[:header.IPv4MinimumSize])
|
||
pkt.NetworkProtocolNumber = header.IPv4ProtocolNumber
|
||
|
||
if err := ns.linkEP.q.Write(pkt); err != nil {
|
||
t.Fatalf("queue.Write: %v", err)
|
||
}
|
||
|
||
// The inject goroutine should detect the self-addressed packet via
|
||
// isSelfDst and deliver it back into gVisor via DeliverLoopback.
|
||
pc.SetReadDeadline(time.Now().Add(5 * time.Second))
|
||
buf := make([]byte, 256)
|
||
n, _, err := pc.ReadFrom(buf)
|
||
if err != nil {
|
||
t.Fatalf("ReadFrom: %v (self-addressed packet was not looped back)", err)
|
||
}
|
||
if got := string(buf[:n]); got != "loopback test" {
|
||
t.Errorf("got %q, want %q", got, "loopback test")
|
||
}
|
||
}
|