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tailscale/wgengine/magicsock/magicsock_test.go

1673 lines
41 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package magicsock
import (
"bytes"
"context"
crand "crypto/rand"
"crypto/tls"
"encoding/binary"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/httptest"
"os"
"runtime"
"strconv"
"strings"
"sync"
"testing"
"time"
"unsafe"
"github.com/tailscale/wireguard-go/device"
"github.com/tailscale/wireguard-go/tun/tuntest"
"golang.org/x/crypto/nacl/box"
"inet.af/netaddr"
"tailscale.com/derp"
"tailscale.com/derp/derphttp"
"tailscale.com/derp/derpmap"
"tailscale.com/ipn/ipnstate"
"tailscale.com/net/stun/stuntest"
"tailscale.com/net/tstun"
"tailscale.com/tailcfg"
"tailscale.com/tstest"
"tailscale.com/tstest/natlab"
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/types/nettype"
"tailscale.com/types/wgkey"
"tailscale.com/util/cibuild"
"tailscale.com/wgengine/filter"
"tailscale.com/wgengine/wgcfg"
"tailscale.com/wgengine/wgcfg/nmcfg"
"tailscale.com/wgengine/wglog"
)
func init() {
os.Setenv("IN_TS_TEST", "1")
}
// WaitReady waits until the magicsock is entirely initialized and connected
// to its home DERP server. This is normally not necessary, since magicsock
// is intended to be entirely asynchronous, but it helps eliminate race
// conditions in tests. In particular, you can't expect two test magicsocks
// to be able to connect to each other through a test DERP unless they are
// both fully initialized before you try.
func (c *Conn) WaitReady(t testing.TB) {
t.Helper()
timer := time.NewTimer(10 * time.Second)
defer timer.Stop()
select {
case <-c.derpStarted:
return
case <-c.connCtx.Done():
t.Fatalf("magicsock.Conn closed while waiting for readiness")
case <-timer.C:
t.Fatalf("timeout waiting for readiness")
}
}
func runDERPAndStun(t *testing.T, logf logger.Logf, l nettype.PacketListener, stunIP netaddr.IP) (derpMap *tailcfg.DERPMap, cleanup func()) {
var serverPrivateKey key.Private
if _, err := crand.Read(serverPrivateKey[:]); err != nil {
t.Fatal(err)
}
d := derp.NewServer(serverPrivateKey, logf)
httpsrv := httptest.NewUnstartedServer(derphttp.Handler(d))
httpsrv.Config.ErrorLog = logger.StdLogger(logf)
httpsrv.Config.TLSNextProto = make(map[string]func(*http.Server, *tls.Conn, http.Handler))
httpsrv.StartTLS()
stunAddr, stunCleanup := stuntest.ServeWithPacketListener(t, l)
m := &tailcfg.DERPMap{
Regions: map[int]*tailcfg.DERPRegion{
1: {
RegionID: 1,
RegionCode: "test",
Nodes: []*tailcfg.DERPNode{
{
Name: "t1",
RegionID: 1,
HostName: "test-node.unused",
IPv4: "127.0.0.1",
IPv6: "none",
STUNPort: stunAddr.Port,
DERPTestPort: httpsrv.Listener.Addr().(*net.TCPAddr).Port,
STUNTestIP: stunIP.String(),
},
},
},
},
}
cleanup = func() {
httpsrv.CloseClientConnections()
httpsrv.Close()
d.Close()
stunCleanup()
}
return m, cleanup
}
// magicStack is a magicsock, plus all the stuff around it that's
// necessary to send and receive packets to test e2e wireguard
// happiness.
type magicStack struct {
privateKey wgkey.Private
epCh chan []tailcfg.Endpoint // endpoint updates produced by this peer
conn *Conn // the magicsock itself
tun *tuntest.ChannelTUN // TUN device to send/receive packets
tsTun *tstun.Wrapper // wrapped tun that implements filtering and wgengine hooks
dev *device.Device // the wireguard-go Device that connects the previous things
wgLogger *wglog.Logger // wireguard-go log wrapper
}
// newMagicStack builds and initializes an idle magicsock and
// friends. You need to call conn.SetNetworkMap and dev.Reconfig
// before anything interesting happens.
func newMagicStack(t testing.TB, logf logger.Logf, l nettype.PacketListener, derpMap *tailcfg.DERPMap, disableLegacy bool) *magicStack {
t.Helper()
privateKey, err := wgkey.NewPrivate()
if err != nil {
t.Fatalf("generating private key: %v", err)
}
epCh := make(chan []tailcfg.Endpoint, 100) // arbitrary
conn, err := NewConn(Options{
Logf: logf,
PacketListener: l,
EndpointsFunc: func(eps []tailcfg.Endpoint) {
epCh <- eps
},
SimulatedNetwork: l != nettype.Std{},
DisableLegacyNetworking: disableLegacy,
})
if err != nil {
t.Fatalf("constructing magicsock: %v", err)
}
conn.Start()
conn.SetDERPMap(derpMap)
if err := conn.SetPrivateKey(privateKey); err != nil {
t.Fatalf("setting private key in magicsock: %v", err)
}
tun := tuntest.NewChannelTUN()
tsTun := tstun.Wrap(logf, tun.TUN())
tsTun.SetFilter(filter.NewAllowAllForTest(logf))
wgLogger := wglog.NewLogger(logf)
dev := device.NewDevice(tsTun, conn.Bind(), wgLogger.DeviceLogger)
dev.Up()
// Wait for magicsock to connect up to DERP.
conn.WaitReady(t)
// Wait for first endpoint update to be available
deadline := time.Now().Add(2 * time.Second)
for len(epCh) == 0 && time.Now().Before(deadline) {
time.Sleep(100 * time.Millisecond)
}
return &magicStack{
privateKey: privateKey,
epCh: epCh,
conn: conn,
tun: tun,
tsTun: tsTun,
dev: dev,
wgLogger: wgLogger,
}
}
func (s *magicStack) Reconfig(cfg *wgcfg.Config) error {
s.wgLogger.SetPeers(cfg.Peers)
return wgcfg.ReconfigDevice(s.dev, cfg, s.conn.logf)
}
func (s *magicStack) String() string {
pub := s.Public()
return pub.ShortString()
}
func (s *magicStack) Close() {
s.dev.Close()
s.conn.Close()
}
func (s *magicStack) Public() key.Public {
return key.Public(s.privateKey.Public())
}
func (s *magicStack) Status() *ipnstate.Status {
var sb ipnstate.StatusBuilder
s.conn.UpdateStatus(&sb)
return sb.Status()
}
// IP returns the Tailscale IP address assigned to this magicStack.
//
// Something external needs to provide a NetworkMap and WireGuard
// configs to the magicStack in order for it to acquire an IP
// address. See meshStacks for one possible source of netmaps and IPs.
func (s *magicStack) IP() netaddr.IP {
for deadline := time.Now().Add(5 * time.Second); time.Now().Before(deadline); time.Sleep(10 * time.Millisecond) {
st := s.Status()
if len(st.TailscaleIPs) > 0 {
return st.TailscaleIPs[0]
}
}
panic("timed out waiting for magicstack to get an IP assigned")
}
// meshStacks monitors epCh on all given ms, and plumbs network maps
// and WireGuard configs into everyone to form a full mesh that has up
// to date endpoint info. Think of it as an extremely stripped down
// and purpose-built Tailscale control plane.
//
// meshStacks only supports disco connections, not legacy logic.
func meshStacks(logf logger.Logf, ms []*magicStack) (cleanup func()) {
ctx, cancel := context.WithCancel(context.Background())
// Serialize all reconfigurations globally, just to keep things
// simpler.
var (
mu sync.Mutex
eps = make([][]tailcfg.Endpoint, len(ms))
)
buildNetmapLocked := func(myIdx int) *netmap.NetworkMap {
me := ms[myIdx]
nm := &netmap.NetworkMap{
PrivateKey: me.privateKey,
NodeKey: tailcfg.NodeKey(me.privateKey.Public()),
Addresses: []netaddr.IPPrefix{netaddr.IPPrefixFrom(netaddr.IPv4(1, 0, 0, byte(myIdx+1)), 32)},
}
for i, peer := range ms {
if i == myIdx {
continue
}
addrs := []netaddr.IPPrefix{netaddr.IPPrefixFrom(netaddr.IPv4(1, 0, 0, byte(i+1)), 32)}
peer := &tailcfg.Node{
ID: tailcfg.NodeID(i + 1),
Name: fmt.Sprintf("node%d", i+1),
Key: tailcfg.NodeKey(peer.privateKey.Public()),
DiscoKey: peer.conn.DiscoPublicKey(),
Addresses: addrs,
AllowedIPs: addrs,
Endpoints: epStrings(eps[i]),
DERP: "127.3.3.40:1",
}
nm.Peers = append(nm.Peers, peer)
}
return nm
}
updateEps := func(idx int, newEps []tailcfg.Endpoint) {
mu.Lock()
defer mu.Unlock()
eps[idx] = newEps
for i, m := range ms {
nm := buildNetmapLocked(i)
m.conn.SetNetworkMap(nm)
peerSet := make(map[key.Public]struct{}, len(nm.Peers))
for _, peer := range nm.Peers {
peerSet[key.Public(peer.Key)] = struct{}{}
}
m.conn.UpdatePeers(peerSet)
wg, err := nmcfg.WGCfg(nm, logf, netmap.AllowSingleHosts, "")
if err != nil {
// We're too far from the *testing.T to be graceful,
// blow up. Shouldn't happen anyway.
panic(fmt.Sprintf("failed to construct wgcfg from netmap: %v", err))
}
if err := m.Reconfig(wg); err != nil {
panic(fmt.Sprintf("device reconfig failed: %v", err))
}
}
}
var wg sync.WaitGroup
wg.Add(len(ms))
for i := range ms {
go func(myIdx int) {
defer wg.Done()
for {
select {
case <-ctx.Done():
return
case eps := <-ms[myIdx].epCh:
logf("conn%d endpoints update", myIdx+1)
updateEps(myIdx, eps)
}
}
}(i)
}
return func() {
cancel()
wg.Wait()
}
}
func TestNewConn(t *testing.T) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
epCh := make(chan string, 16)
epFunc := func(endpoints []tailcfg.Endpoint) {
for _, ep := range endpoints {
epCh <- ep.Addr.String()
}
}
stunAddr, stunCleanupFn := stuntest.Serve(t)
defer stunCleanupFn()
port := pickPort(t)
conn, err := NewConn(Options{
Port: port,
EndpointsFunc: epFunc,
Logf: t.Logf,
DisableLegacyNetworking: true,
})
if err != nil {
t.Fatal(err)
}
defer conn.Close()
conn.SetDERPMap(stuntest.DERPMapOf(stunAddr.String()))
conn.SetPrivateKey(wgkey.Private(key.NewPrivate()))
conn.Start()
go func() {
var pkt [64 << 10]byte
for {
_, _, err := conn.receiveIPv4(pkt[:])
if err != nil {
return
}
}
}()
timeout := time.After(10 * time.Second)
var endpoints []string
suffix := fmt.Sprintf(":%d", port)
collectEndpoints:
for {
select {
case ep := <-epCh:
endpoints = append(endpoints, ep)
if strings.HasSuffix(ep, suffix) {
break collectEndpoints
}
case <-timeout:
t.Fatalf("timeout with endpoints: %v", endpoints)
}
}
}
func pickPort(t testing.TB) uint16 {
t.Helper()
conn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
t.Fatal(err)
}
defer conn.Close()
return uint16(conn.LocalAddr().(*net.UDPAddr).Port)
}
func TestPickDERPFallback(t *testing.T) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
c := newConn()
c.derpMap = derpmap.Prod()
a := c.pickDERPFallback()
if a == 0 {
t.Fatalf("pickDERPFallback returned 0")
}
// Test that it's consistent.
for i := 0; i < 50; i++ {
b := c.pickDERPFallback()
if a != b {
t.Fatalf("got inconsistent %d vs %d values", a, b)
}
}
// Test that that the pointer value of c is blended in and
// distribution over nodes works.
got := map[int]int{}
for i := 0; i < 50; i++ {
c = newConn()
c.derpMap = derpmap.Prod()
got[c.pickDERPFallback()]++
}
t.Logf("distribution: %v", got)
if len(got) < 2 {
t.Errorf("expected more than 1 node; got %v", got)
}
// Test that stickiness works.
const someNode = 123456
c.myDerp = someNode
if got := c.pickDERPFallback(); got != someNode {
t.Errorf("not sticky: got %v; want %v", got, someNode)
}
// But move if peers are elsewhere.
const otherNode = 789
c.addrsByKey = map[key.Public]*addrSet{
{1}: {ipPorts: []netaddr.IPPort{netaddr.IPPortFrom(derpMagicIPAddr, otherNode)}},
}
if got := c.pickDERPFallback(); got != otherNode {
t.Errorf("didn't join peers: got %v; want %v", got, someNode)
}
}
func makeConfigs(t *testing.T, addrs []netaddr.IPPort) []wgcfg.Config {
t.Helper()
var privKeys []wgkey.Private
var addresses [][]netaddr.IPPrefix
for i := range addrs {
privKey, err := wgkey.NewPrivate()
if err != nil {
t.Fatal(err)
}
privKeys = append(privKeys, wgkey.Private(privKey))
addresses = append(addresses, []netaddr.IPPrefix{
netaddr.MustParseIPPrefix(fmt.Sprintf("1.0.0.%d/32", i+1)),
})
}
var cfgs []wgcfg.Config
for i := range addrs {
cfg := wgcfg.Config{
Name: fmt.Sprintf("peer%d", i+1),
PrivateKey: privKeys[i],
Addresses: addresses[i],
}
for peerNum, addr := range addrs {
if peerNum == i {
continue
}
publicKey := privKeys[peerNum].Public()
peer := wgcfg.Peer{
PublicKey: publicKey,
AllowedIPs: addresses[peerNum],
Endpoints: wgcfg.Endpoints{
PublicKey: publicKey,
IPPorts: wgcfg.NewIPPortSet(addr),
},
PersistentKeepalive: 25,
}
cfg.Peers = append(cfg.Peers, peer)
}
cfgs = append(cfgs, cfg)
}
return cfgs
}
// TestDeviceStartStop exercises the startup and shutdown logic of
// wireguard-go, which is intimately intertwined with magicsock's own
// lifecycle. We seem to be good at generating deadlocks here, so if
// this test fails you should suspect a deadlock somewhere in startup
// or shutdown. It may be an infrequent flake, so run with
// -count=10000 to be sure.
func TestDeviceStartStop(t *testing.T) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
conn, err := NewConn(Options{
EndpointsFunc: func(eps []tailcfg.Endpoint) {},
Logf: t.Logf,
DisableLegacyNetworking: true,
})
if err != nil {
t.Fatal(err)
}
conn.Start()
defer conn.Close()
tun := tuntest.NewChannelTUN()
wgLogger := wglog.NewLogger(t.Logf)
dev := device.NewDevice(tun.TUN(), conn.Bind(), wgLogger.DeviceLogger)
dev.Up()
dev.Close()
}
// Exercise a code path in sendDiscoMessage if the connection has been closed.
func TestConnClosed(t *testing.T) {
mstun := &natlab.Machine{Name: "stun"}
m1 := &natlab.Machine{Name: "m1"}
m2 := &natlab.Machine{Name: "m2"}
inet := natlab.NewInternet()
sif := mstun.Attach("eth0", inet)
m1if := m1.Attach("eth0", inet)
m2if := m2.Attach("eth0", inet)
d := &devices{
m1: m1,
m1IP: m1if.V4(),
m2: m2,
m2IP: m2if.V4(),
stun: mstun,
stunIP: sif.V4(),
}
logf, closeLogf := logger.LogfCloser(t.Logf)
defer closeLogf()
derpMap, cleanup := runDERPAndStun(t, logf, d.stun, d.stunIP)
defer cleanup()
ms1 := newMagicStack(t, logger.WithPrefix(logf, "conn1: "), d.m1, derpMap, true)
defer ms1.Close()
ms2 := newMagicStack(t, logger.WithPrefix(logf, "conn2: "), d.m2, derpMap, true)
defer ms2.Close()
cleanup = meshStacks(t.Logf, []*magicStack{ms1, ms2})
defer cleanup()
pkt := tuntest.Ping(ms2.IP().IPAddr().IP, ms1.IP().IPAddr().IP)
if len(ms1.conn.activeDerp) == 0 {
t.Errorf("unexpected DERP empty got: %v want: >0", len(ms1.conn.activeDerp))
}
ms1.conn.Close()
ms2.conn.Close()
// This should hit a c.closed conditional in sendDiscoMessage() and return immediately.
ms1.tun.Outbound <- pkt
select {
case <-ms2.tun.Inbound:
t.Error("unexpected response with connection closed")
case <-time.After(100 * time.Millisecond):
}
if len(ms1.conn.activeDerp) > 0 {
t.Errorf("unexpected DERP active got: %v want:0", len(ms1.conn.activeDerp))
}
}
func makeNestable(t *testing.T) (logf logger.Logf, setT func(t *testing.T)) {
var mu sync.RWMutex
cur := t
setT = func(t *testing.T) {
mu.Lock()
cur = t
mu.Unlock()
}
logf = func(s string, args ...interface{}) {
mu.RLock()
t := cur
t.Helper()
t.Logf(s, args...)
mu.RUnlock()
}
return logf, setT
}
func TestTwoDevicePing(t *testing.T) {
l, ip := nettype.Std{}, netaddr.IPv4(127, 0, 0, 1)
n := &devices{
m1: l,
m1IP: ip,
m2: l,
m2IP: ip,
stun: l,
stunIP: ip,
}
testTwoDevicePing(t, n)
}
func TestActiveDiscovery(t *testing.T) {
t.Run("simple_internet", func(t *testing.T) {
t.Parallel()
mstun := &natlab.Machine{Name: "stun"}
m1 := &natlab.Machine{Name: "m1"}
m2 := &natlab.Machine{Name: "m2"}
inet := natlab.NewInternet()
sif := mstun.Attach("eth0", inet)
m1if := m1.Attach("eth0", inet)
m2if := m2.Attach("eth0", inet)
n := &devices{
m1: m1,
m1IP: m1if.V4(),
m2: m2,
m2IP: m2if.V4(),
stun: mstun,
stunIP: sif.V4(),
}
testActiveDiscovery(t, n)
})
t.Run("facing_easy_firewalls", func(t *testing.T) {
mstun := &natlab.Machine{Name: "stun"}
m1 := &natlab.Machine{
Name: "m1",
PacketHandler: &natlab.Firewall{},
}
m2 := &natlab.Machine{
Name: "m2",
PacketHandler: &natlab.Firewall{},
}
inet := natlab.NewInternet()
sif := mstun.Attach("eth0", inet)
m1if := m1.Attach("eth0", inet)
m2if := m2.Attach("eth0", inet)
n := &devices{
m1: m1,
m1IP: m1if.V4(),
m2: m2,
m2IP: m2if.V4(),
stun: mstun,
stunIP: sif.V4(),
}
testActiveDiscovery(t, n)
})
t.Run("facing_nats", func(t *testing.T) {
mstun := &natlab.Machine{Name: "stun"}
m1 := &natlab.Machine{
Name: "m1",
PacketHandler: &natlab.Firewall{},
}
nat1 := &natlab.Machine{
Name: "nat1",
}
m2 := &natlab.Machine{
Name: "m2",
PacketHandler: &natlab.Firewall{},
}
nat2 := &natlab.Machine{
Name: "nat2",
}
inet := natlab.NewInternet()
lan1 := &natlab.Network{
Name: "lan1",
Prefix4: mustPrefix("192.168.0.0/24"),
}
lan2 := &natlab.Network{
Name: "lan2",
Prefix4: mustPrefix("192.168.1.0/24"),
}
sif := mstun.Attach("eth0", inet)
nat1WAN := nat1.Attach("wan", inet)
nat1LAN := nat1.Attach("lan1", lan1)
nat2WAN := nat2.Attach("wan", inet)
nat2LAN := nat2.Attach("lan2", lan2)
m1if := m1.Attach("eth0", lan1)
m2if := m2.Attach("eth0", lan2)
lan1.SetDefaultGateway(nat1LAN)
lan2.SetDefaultGateway(nat2LAN)
nat1.PacketHandler = &natlab.SNAT44{
Machine: nat1,
ExternalInterface: nat1WAN,
Firewall: &natlab.Firewall{
TrustedInterface: nat1LAN,
},
}
nat2.PacketHandler = &natlab.SNAT44{
Machine: nat2,
ExternalInterface: nat2WAN,
Firewall: &natlab.Firewall{
TrustedInterface: nat2LAN,
},
}
n := &devices{
m1: m1,
m1IP: m1if.V4(),
m2: m2,
m2IP: m2if.V4(),
stun: mstun,
stunIP: sif.V4(),
}
testActiveDiscovery(t, n)
})
}
func mustPrefix(s string) netaddr.IPPrefix {
pfx, err := netaddr.ParseIPPrefix(s)
if err != nil {
panic(err)
}
return pfx
}
type devices struct {
m1 nettype.PacketListener
m1IP netaddr.IP
m2 nettype.PacketListener
m2IP netaddr.IP
stun nettype.PacketListener
stunIP netaddr.IP
}
// newPinger starts continuously sending test packets from srcM to
// dstM, until cleanup is invoked to stop it. Each ping has 1 second
// to transit the network. It is a test failure to lose a ping.
func newPinger(t *testing.T, logf logger.Logf, src, dst *magicStack) (cleanup func()) {
ctx, cancel := context.WithCancel(context.Background())
done := make(chan struct{})
one := func() bool {
// TODO(danderson): requiring exactly zero packet loss
// will probably be too strict for some tests we'd like to
// run (e.g. discovery switching to a new path on
// failure). Figure out what kind of thing would be
// acceptable to test instead of "every ping must
// transit".
pkt := tuntest.Ping(dst.IP().IPAddr().IP, src.IP().IPAddr().IP)
select {
case src.tun.Outbound <- pkt:
case <-ctx.Done():
return false
}
select {
case <-dst.tun.Inbound:
return true
case <-time.After(10 * time.Second):
// Very generous timeout here because depending on
// magicsock setup races, the first handshake might get
// eaten by the receiving end (if wireguard-go hasn't been
// configured quite yet), so we have to wait for at least
// the first retransmit from wireguard before we declare
// failure.
t.Errorf("timed out waiting for ping to transit")
return true
case <-ctx.Done():
// Try a little bit longer to consume the packet we're
// waiting for. This is to deal with shutdown races, where
// natlab may still be delivering a packet to us from a
// goroutine.
select {
case <-dst.tun.Inbound:
case <-time.After(time.Second):
}
return false
}
}
cleanup = func() {
cancel()
<-done
}
// Synchronously transit one ping to get things started. This is
// nice because it means that newPinger returning means we've
// worked through initial connectivity.
if !one() {
cleanup()
return
}
go func() {
logf("sending ping stream from %s (%s) to %s (%s)", src, src.IP(), dst, dst.IP())
defer close(done)
for one() {
}
}()
return cleanup
}
// testActiveDiscovery verifies that two magicStacks tied to the given
// devices can establish a direct p2p connection with each other. See
// TestActiveDiscovery for the various configurations of devices that
// get exercised.
func testActiveDiscovery(t *testing.T, d *devices) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
tlogf, setT := makeNestable(t)
setT(t)
start := time.Now()
wlogf := func(msg string, args ...interface{}) {
t.Helper()
msg = fmt.Sprintf("%s: %s", time.Since(start).Truncate(time.Microsecond), msg)
tlogf(msg, args...)
}
logf, closeLogf := logger.LogfCloser(wlogf)
defer closeLogf()
derpMap, cleanup := runDERPAndStun(t, logf, d.stun, d.stunIP)
defer cleanup()
m1 := newMagicStack(t, logger.WithPrefix(logf, "conn1: "), d.m1, derpMap, true)
defer m1.Close()
m2 := newMagicStack(t, logger.WithPrefix(logf, "conn2: "), d.m2, derpMap, true)
defer m2.Close()
cleanup = meshStacks(logf, []*magicStack{m1, m2})
defer cleanup()
m1IP := m1.IP()
m2IP := m2.IP()
logf("IPs: %s %s", m1IP, m2IP)
cleanup = newPinger(t, logf, m1, m2)
defer cleanup()
// Everything is now up and running, active discovery should find
// a direct path between our peers. Wait for it to switch away
// from DERP.
mustDirect := func(m1, m2 *magicStack) {
lastLog := time.Now().Add(-time.Minute)
// See https://github.com/tailscale/tailscale/issues/654 for a discussion of this deadline.
for deadline := time.Now().Add(10 * time.Second); time.Now().Before(deadline); time.Sleep(10 * time.Millisecond) {
pst := m1.Status().Peer[m2.Public()]
if pst.CurAddr != "" {
logf("direct link %s->%s found with addr %s", m1, m2, pst.CurAddr)
return
}
if now := time.Now(); now.Sub(lastLog) > time.Second {
logf("no direct path %s->%s yet, addrs %v", m1, m2, pst.Addrs)
lastLog = now
}
}
t.Errorf("magicsock did not find a direct path from %s to %s", m1, m2)
}
mustDirect(m1, m2)
mustDirect(m2, m1)
logf("starting cleanup")
}
func testTwoDevicePing(t *testing.T, d *devices) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
// This gets reassigned inside every test, so that the connections
// all log using the "current" t.Logf function. Sigh.
nestedLogf, setT := makeNestable(t)
logf, closeLogf := logger.LogfCloser(nestedLogf)
defer closeLogf()
derpMap, cleanup := runDERPAndStun(t, logf, d.stun, d.stunIP)
defer cleanup()
m1 := newMagicStack(t, logf, d.m1, derpMap, false)
defer m1.Close()
m2 := newMagicStack(t, logf, d.m2, derpMap, false)
defer m2.Close()
addrs := []netaddr.IPPort{
netaddr.IPPortFrom(d.m1IP, m1.conn.LocalPort()),
netaddr.IPPortFrom(d.m2IP, m2.conn.LocalPort()),
}
cfgs := makeConfigs(t, addrs)
if err := m1.Reconfig(&cfgs[0]); err != nil {
t.Fatal(err)
}
if err := m2.Reconfig(&cfgs[1]); err != nil {
t.Fatal(err)
}
// In the normal case, pings succeed immediately.
// However, in the case of a handshake race, we need to retry.
// With very bad luck, we can need to retry multiple times.
allowedRetries := 3
if cibuild.On() {
// Allow extra retries on small/flaky/loaded CI machines.
allowedRetries *= 2
}
// Retries take 5s each. Add 1s for some processing time.
pingTimeout := 5*time.Second*time.Duration(allowedRetries) + time.Second
// sendWithTimeout sends msg using send, checking that it is received unchanged from in.
// It resends once per second until the send succeeds, or pingTimeout time has elapsed.
sendWithTimeout := func(msg []byte, in chan []byte, send func()) error {
start := time.Now()
for time.Since(start) < pingTimeout {
send()
select {
case recv := <-in:
if !bytes.Equal(msg, recv) {
return errors.New("ping did not transit correctly")
}
return nil
case <-time.After(time.Second):
// try again
}
}
return errors.New("ping timed out")
}
ping1 := func(t *testing.T) {
msg2to1 := tuntest.Ping(net.ParseIP("1.0.0.1"), net.ParseIP("1.0.0.2"))
send := func() {
m2.tun.Outbound <- msg2to1
t.Log("ping1 sent")
}
in := m1.tun.Inbound
if err := sendWithTimeout(msg2to1, in, send); err != nil {
t.Error(err)
}
}
ping2 := func(t *testing.T) {
msg1to2 := tuntest.Ping(net.ParseIP("1.0.0.2"), net.ParseIP("1.0.0.1"))
send := func() {
m1.tun.Outbound <- msg1to2
t.Log("ping2 sent")
}
in := m2.tun.Inbound
if err := sendWithTimeout(msg1to2, in, send); err != nil {
t.Error(err)
}
}
outerT := t
t.Run("ping 1.0.0.1", func(t *testing.T) {
setT(t)
defer setT(outerT)
ping1(t)
})
t.Run("ping 1.0.0.2", func(t *testing.T) {
setT(t)
defer setT(outerT)
ping2(t)
})
t.Run("ping 1.0.0.2 via SendPacket", func(t *testing.T) {
setT(t)
defer setT(outerT)
msg1to2 := tuntest.Ping(net.ParseIP("1.0.0.2"), net.ParseIP("1.0.0.1"))
send := func() {
if err := m1.tsTun.InjectOutbound(msg1to2); err != nil {
t.Fatal(err)
}
t.Log("SendPacket sent")
}
in := m2.tun.Inbound
if err := sendWithTimeout(msg1to2, in, send); err != nil {
t.Error(err)
}
})
t.Run("no-op dev1 reconfig", func(t *testing.T) {
setT(t)
defer setT(outerT)
if err := m1.Reconfig(&cfgs[0]); err != nil {
t.Fatal(err)
}
ping1(t)
ping2(t)
})
}
// TestAddrSet tests addrSet appendDests and updateDst.
func TestAddrSet(t *testing.T) {
tstest.PanicOnLog()
tstest.ResourceCheck(t)
mustIPPortPtr := func(s string) *netaddr.IPPort {
ipp := netaddr.MustParseIPPort(s)
return &ipp
}
ipps := func(ss ...string) (ret []netaddr.IPPort) {
t.Helper()
for _, s := range ss {
ret = append(ret, netaddr.MustParseIPPort(s))
}
return ret
}
joinUDPs := func(in []netaddr.IPPort) string {
var sb strings.Builder
for i, ua := range in {
if i > 0 {
sb.WriteByte(',')
}
sb.WriteString(ua.String())
}
return sb.String()
}
var (
regPacket = []byte("some regular packet")
sprayPacket = []byte("0000")
)
binary.LittleEndian.PutUint32(sprayPacket[:4], device.MessageInitiationType)
if !shouldSprayPacket(sprayPacket) {
t.Fatal("sprayPacket should be classified as a spray packet for testing")
}
// A step is either a b+want appendDests tests, or an
// UpdateDst call, depending on which fields are set.
type step struct {
// advance is the time to advance the fake clock
// before the step.
advance time.Duration
// updateDst, if set, does an UpdateDst call and
// b+want are ignored.
updateDst *netaddr.IPPort
b []byte
want string // comma-separated
}
tests := []struct {
name string
as *addrSet
steps []step
logCheck func(t *testing.T, logged []byte)
}{
{
name: "reg_packet_no_curaddr",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: -1, // unknown
roamAddr: nil,
},
steps: []step{
{b: regPacket, want: "127.3.3.40:1"},
},
},
{
name: "reg_packet_have_curaddr",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: 1, // global IP
roamAddr: nil,
},
steps: []step{
{b: regPacket, want: "123.45.67.89:123"},
},
},
{
name: "reg_packet_have_roamaddr",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: 2, // should be ignored
roamAddr: mustIPPortPtr("5.6.7.8:123"),
},
steps: []step{
{b: regPacket, want: "5.6.7.8:123"},
{updateDst: mustIPPortPtr("10.0.0.1:123")}, // no more roaming
{b: regPacket, want: "10.0.0.1:123"},
},
},
{
name: "start_roaming",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: 2,
},
steps: []step{
{b: regPacket, want: "10.0.0.1:123"},
{updateDst: mustIPPortPtr("4.5.6.7:123")},
{b: regPacket, want: "4.5.6.7:123"},
{updateDst: mustIPPortPtr("5.6.7.8:123")},
{b: regPacket, want: "5.6.7.8:123"},
{updateDst: mustIPPortPtr("123.45.67.89:123")}, // end roaming
{b: regPacket, want: "123.45.67.89:123"},
},
},
{
name: "spray_packet",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: 2, // should be ignored
roamAddr: mustIPPortPtr("5.6.7.8:123"),
},
steps: []step{
{b: sprayPacket, want: "127.3.3.40:1,123.45.67.89:123,10.0.0.1:123,5.6.7.8:123"},
{advance: 300 * time.Millisecond, b: regPacket, want: "127.3.3.40:1,123.45.67.89:123,10.0.0.1:123,5.6.7.8:123"},
{advance: 300 * time.Millisecond, b: regPacket, want: "127.3.3.40:1,123.45.67.89:123,10.0.0.1:123,5.6.7.8:123"},
{advance: 3, b: regPacket, want: "5.6.7.8:123"},
{advance: 2 * time.Millisecond, updateDst: mustIPPortPtr("10.0.0.1:123")},
{advance: 3, b: regPacket, want: "10.0.0.1:123"},
},
},
{
name: "low_pri",
as: &addrSet{
ipPorts: ipps("127.3.3.40:1", "123.45.67.89:123", "10.0.0.1:123"),
curAddr: 2,
},
steps: []step{
{updateDst: mustIPPortPtr("123.45.67.89:123")},
{updateDst: mustIPPortPtr("123.45.67.89:123")},
},
logCheck: func(t *testing.T, logged []byte) {
if n := bytes.Count(logged, []byte(", keeping current ")); n != 1 {
t.Errorf("low-prio keeping current logged %d times; want 1", n)
}
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
faket := time.Unix(0, 0)
var logBuf bytes.Buffer
tt.as.Logf = func(format string, args ...interface{}) {
fmt.Fprintf(&logBuf, format, args...)
t.Logf(format, args...)
}
tt.as.clock = func() time.Time { return faket }
for i, st := range tt.steps {
faket = faket.Add(st.advance)
if st.updateDst != nil {
if err := tt.as.updateDst(*st.updateDst); err != nil {
t.Fatal(err)
}
continue
}
got, _ := tt.as.appendDests(nil, st.b)
if gotStr := joinUDPs(got); gotStr != st.want {
t.Errorf("step %d: got %v; want %v", i, gotStr, st.want)
}
}
if tt.logCheck != nil {
tt.logCheck(t, logBuf.Bytes())
}
})
}
}
func TestDiscoMessage(t *testing.T) {
c := newConn()
c.logf = t.Logf
c.privateKey = key.NewPrivate()
peer1Pub := c.DiscoPublicKey()
peer1Priv := c.discoPrivate
c.endpointOfDisco = map[tailcfg.DiscoKey]*discoEndpoint{
tailcfg.DiscoKey(peer1Pub): {
// ... (enough for this test)
},
}
c.nodeOfDisco = map[tailcfg.DiscoKey]*tailcfg.Node{
tailcfg.DiscoKey(peer1Pub): {
// ... (enough for this test)
},
}
const payload = "why hello"
var nonce [24]byte
crand.Read(nonce[:])
pkt := append([]byte("TS💬"), peer1Pub[:]...)
pkt = append(pkt, nonce[:]...)
pkt = box.Seal(pkt, []byte(payload), &nonce, c.discoPrivate.Public().B32(), peer1Priv.B32())
got := c.handleDiscoMessage(pkt, netaddr.IPPort{})
if !got {
t.Error("failed to open it")
}
}
// tests that having a discoEndpoint.String prevents wireguard-go's
// log.Printf("%v") of its conn.Endpoint values from using reflect to
// walk into read mutex while they're being used and then causing data
// races.
func TestDiscoStringLogRace(t *testing.T) {
de := new(discoEndpoint)
var wg sync.WaitGroup
wg.Add(2)
go func() {
defer wg.Done()
fmt.Fprintf(ioutil.Discard, "%v", de)
}()
go func() {
defer wg.Done()
de.mu.Lock()
}()
wg.Wait()
}
func Test32bitAlignment(t *testing.T) {
var de discoEndpoint
if off := unsafe.Offsetof(de.lastRecvUnixAtomic); off%8 != 0 {
t.Fatalf("discoEndpoint.lastRecvUnixAtomic is not 8-byte aligned")
}
if !de.isFirstRecvActivityInAwhile() { // verify this doesn't panic on 32-bit
t.Error("expected true")
}
if de.isFirstRecvActivityInAwhile() {
t.Error("expected false on second call")
}
}
// newNonLegacyTestConn returns a new Conn with DisableLegacyNetworking set true.
func newNonLegacyTestConn(t testing.TB) *Conn {
t.Helper()
port := pickPort(t)
conn, err := NewConn(Options{
Logf: t.Logf,
Port: port,
EndpointsFunc: func(eps []tailcfg.Endpoint) {
t.Logf("endpoints: %q", eps)
},
DisableLegacyNetworking: true,
})
if err != nil {
t.Fatal(err)
}
return conn
}
func makeEndpoint(tb testing.TB, public tailcfg.NodeKey, disco tailcfg.DiscoKey) string {
tb.Helper()
ep := wgcfg.Endpoints{
PublicKey: wgkey.Key(public),
DiscoKey: disco,
}
buf, err := json.Marshal(ep)
if err != nil {
tb.Fatal(err)
}
return string(buf)
}
// addTestEndpoint sets conn's network map to a single peer expected
// to receive packets from sendConn (or DERP), and returns that peer's
// nodekey and discokey.
func addTestEndpoint(tb testing.TB, conn *Conn, sendConn net.PacketConn) (tailcfg.NodeKey, tailcfg.DiscoKey) {
// Give conn just enough state that it'll recognize sendConn as a
// valid peer and not fall through to the legacy magicsock
// codepath.
discoKey := tailcfg.DiscoKey{31: 1}
nodeKey := tailcfg.NodeKey{0: 'N', 1: 'K'}
conn.SetNetworkMap(&netmap.NetworkMap{
Peers: []*tailcfg.Node{
{
Key: nodeKey,
DiscoKey: discoKey,
Endpoints: []string{sendConn.LocalAddr().String()},
},
},
})
conn.SetPrivateKey(wgkey.Private{0: 1})
_, err := conn.ParseEndpoint(makeEndpoint(tb, nodeKey, discoKey))
if err != nil {
tb.Fatal(err)
}
conn.addValidDiscoPathForTest(discoKey, netaddr.MustParseIPPort(sendConn.LocalAddr().String()))
return nodeKey, discoKey
}
func setUpReceiveFrom(tb testing.TB) (roundTrip func()) {
conn := newNonLegacyTestConn(tb)
tb.Cleanup(func() { conn.Close() })
conn.logf = logger.Discard
sendConn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
tb.Fatal(err)
}
tb.Cleanup(func() { sendConn.Close() })
addTestEndpoint(tb, conn, sendConn)
var dstAddr net.Addr = conn.pconn4.LocalAddr()
sendBuf := make([]byte, 1<<10)
for i := range sendBuf {
sendBuf[i] = 'x'
}
buf := make([]byte, 2<<10)
return func() {
if _, err := sendConn.WriteTo(sendBuf, dstAddr); err != nil {
tb.Fatalf("WriteTo: %v", err)
}
n, ep, err := conn.receiveIPv4(buf)
if err != nil {
tb.Fatal(err)
}
_ = n
_ = ep
}
}
// goMajorVersion reports the major Go version and whether it is a Tailscale fork.
// If parsing fails, goMajorVersion returns 0, false.
func goMajorVersion(s string) (version int, isTS bool) {
if !strings.HasPrefix(s, "go1.") {
return 0, false
}
mm := s[len("go1."):]
var major, rest string
for _, sep := range []string{".", "rc", "beta"} {
i := strings.Index(mm, sep)
if i > 0 {
major, rest = mm[:i], mm[i:]
break
}
}
if major == "" {
major = mm
}
n, err := strconv.Atoi(major)
if err != nil {
return 0, false
}
return n, strings.Contains(rest, "ts")
}
func TestGoMajorVersion(t *testing.T) {
tests := []struct {
version string
wantN int
wantTS bool
}{
{"go1.15.8", 15, false},
{"go1.16rc1", 16, false},
{"go1.16rc1", 16, false},
{"go1.15.5-ts3bd89195a3", 15, true},
{"go1.15", 15, false},
}
for _, tt := range tests {
n, ts := goMajorVersion(tt.version)
if tt.wantN != n || tt.wantTS != ts {
t.Errorf("goMajorVersion(%s) = %v, %v, want %v, %v", tt.version, n, ts, tt.wantN, tt.wantTS)
}
}
}
func TestReceiveFromAllocs(t *testing.T) {
// Go 1.16 and before: allow 3 allocs.
// Go Tailscale fork, Go 1.17+: only allow 2 allocs.
major, ts := goMajorVersion(runtime.Version())
maxAllocs := 3
if major >= 17 || ts {
maxAllocs = 2
}
t.Logf("allowing %d allocs for Go version %q", maxAllocs, runtime.Version())
roundTrip := setUpReceiveFrom(t)
avg := int(testing.AllocsPerRun(100, roundTrip))
if avg > maxAllocs {
t.Fatalf("expected %d allocs in ReceiveFrom, got %v", maxAllocs, avg)
}
}
func BenchmarkReceiveFrom(b *testing.B) {
roundTrip := setUpReceiveFrom(b)
for i := 0; i < b.N; i++ {
roundTrip()
}
}
func BenchmarkReceiveFrom_Native(b *testing.B) {
recvConn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
b.Fatal(err)
}
defer recvConn.Close()
recvConnUDP := recvConn.(*net.UDPConn)
sendConn, err := net.ListenPacket("udp4", "127.0.0.1:0")
if err != nil {
b.Fatal(err)
}
defer sendConn.Close()
var dstAddr net.Addr = recvConn.LocalAddr()
sendBuf := make([]byte, 1<<10)
for i := range sendBuf {
sendBuf[i] = 'x'
}
buf := make([]byte, 2<<10)
for i := 0; i < b.N; i++ {
if _, err := sendConn.WriteTo(sendBuf, dstAddr); err != nil {
b.Fatalf("WriteTo: %v", err)
}
if _, _, err := recvConnUDP.ReadFromUDP(buf); err != nil {
b.Fatalf("ReadFromUDP: %v", err)
}
}
}
func logBufWriter(buf *bytes.Buffer) logger.Logf {
return func(format string, a ...interface{}) {
fmt.Fprintf(buf, format, a...)
if !bytes.HasSuffix(buf.Bytes(), []byte("\n")) {
buf.WriteByte('\n')
}
}
}
// Test that a netmap update where node changes its node key but
// doesn't change its disco key doesn't result in a broken state.
//
// https://github.com/tailscale/tailscale/issues/1391
func TestSetNetworkMapChangingNodeKey(t *testing.T) {
conn := newNonLegacyTestConn(t)
t.Cleanup(func() { conn.Close() })
var logBuf bytes.Buffer
conn.logf = logBufWriter(&logBuf)
conn.SetPrivateKey(wgkey.Private{0: 1})
discoKey := tailcfg.DiscoKey{31: 1}
nodeKey1 := tailcfg.NodeKey{0: 'N', 1: 'K', 2: '1'}
nodeKey2 := tailcfg.NodeKey{0: 'N', 1: 'K', 2: '2'}
conn.SetNetworkMap(&netmap.NetworkMap{
Peers: []*tailcfg.Node{
{
Key: nodeKey1,
DiscoKey: discoKey,
Endpoints: []string{"192.168.1.2:345"},
},
},
})
_, err := conn.ParseEndpoint(makeEndpoint(t, nodeKey1, discoKey))
if err != nil {
t.Fatal(err)
}
for i := 0; i < 3; i++ {
conn.SetNetworkMap(&netmap.NetworkMap{
Peers: []*tailcfg.Node{
{
Key: nodeKey2,
DiscoKey: discoKey,
Endpoints: []string{"192.168.1.2:345"},
},
},
})
}
de := conn.endpointOfDisco[discoKey]
if de != nil && de.publicKey != nodeKey2 {
t.Fatalf("discoEndpoint public key = %q; want %q", de.publicKey[:], nodeKey2[:])
}
log := logBuf.String()
wantSub := map[string]int{
"magicsock: got updated network map; 1 peers (1 with discokey)": 2,
"magicsock: disco key discokey:0000000000000000000000000000000000000000000000000000000000000001 changed from node key [TksxA] to [TksyA]": 1,
}
for sub, want := range wantSub {
got := strings.Count(log, sub)
if got != want {
t.Errorf("in log, count of substring %q = %v; want %v", sub, got, want)
}
}
if t.Failed() {
t.Logf("log output: %s", log)
}
}
func TestRebindStress(t *testing.T) {
conn := newNonLegacyTestConn(t)
var logBuf bytes.Buffer
conn.logf = logBufWriter(&logBuf)
closed := false
t.Cleanup(func() {
if !closed {
conn.Close()
}
})
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
errc := make(chan error, 1)
go func() {
buf := make([]byte, 1500)
for {
_, _, err := conn.receiveIPv4(buf)
if ctx.Err() != nil {
errc <- nil
return
}
if err != nil {
errc <- err
return
}
}
}()
var wg sync.WaitGroup
wg.Add(2)
go func() {
defer wg.Done()
for i := 0; i < 2000; i++ {
conn.Rebind()
}
}()
go func() {
defer wg.Done()
for i := 0; i < 2000; i++ {
conn.Rebind()
}
}()
wg.Wait()
cancel()
if err := conn.Close(); err != nil {
t.Fatal(err)
}
closed = true
err := <-errc
if err != nil {
t.Fatalf("Got ReceiveIPv4 error: %v (is closed = %v). Log:\n%s", err, errors.Is(err, net.ErrClosed), logBuf.Bytes())
}
}
func TestEndpointSetsEqual(t *testing.T) {
s := func(ports ...uint16) (ret []tailcfg.Endpoint) {
for _, port := range ports {
ret = append(ret, tailcfg.Endpoint{
Addr: netaddr.IPPortFrom(netaddr.IP{}, port),
})
}
return
}
tests := []struct {
a, b []tailcfg.Endpoint
want bool
}{
{
want: true,
},
{
a: s(1, 2, 3),
b: s(1, 2, 3),
want: true,
},
{
a: s(1, 2),
b: s(2, 1),
want: true,
},
{
a: s(1, 2),
b: s(2, 1, 1),
want: true,
},
{
a: s(1, 2, 2),
b: s(2, 1),
want: true,
},
{
a: s(1, 2, 2),
b: s(2, 1, 1),
want: true,
},
{
a: s(1, 2, 2, 3),
b: s(2, 1, 1),
want: false,
},
{
a: s(1, 2, 2),
b: s(2, 1, 1, 3),
want: false,
},
}
for _, tt := range tests {
if got := endpointSetsEqual(tt.a, tt.b); got != tt.want {
t.Errorf("%q vs %q = %v; want %v", tt.a, tt.b, got, tt.want)
}
}
}
func TestBetterAddr(t *testing.T) {
const ms = time.Millisecond
al := func(ipps string, d time.Duration) addrLatency {
return addrLatency{netaddr.MustParseIPPort(ipps), d}
}
zero := addrLatency{}
tests := []struct {
a, b addrLatency
want bool
}{
{a: zero, b: zero, want: false},
{a: al("10.0.0.2:123", 5*ms), b: zero, want: true},
{a: zero, b: al("10.0.0.2:123", 5*ms), want: false},
{a: al("10.0.0.2:123", 5*ms), b: al("1.2.3.4:555", 6*ms), want: true},
{a: al("10.0.0.2:123", 5*ms), b: al("10.0.0.2:123", 10*ms), want: false}, // same IPPort
// Prefer IPv6 if roughly equivalent:
{
a: al("[2001::5]:123", 100*ms),
b: al("1.2.3.4:555", 91*ms),
want: true,
},
{
a: al("1.2.3.4:555", 91*ms),
b: al("[2001::5]:123", 100*ms),
want: false,
},
// But not if IPv4 is much faster:
{
a: al("[2001::5]:123", 100*ms),
b: al("1.2.3.4:555", 30*ms),
want: false,
},
{
a: al("1.2.3.4:555", 30*ms),
b: al("[2001::5]:123", 100*ms),
want: true,
},
}
for _, tt := range tests {
got := betterAddr(tt.a, tt.b)
if got != tt.want {
t.Errorf("betterAddr(%+v, %+v) = %v; want %v", tt.a, tt.b, got, tt.want)
continue
}
gotBack := betterAddr(tt.b, tt.a)
if got && gotBack {
t.Errorf("betterAddr(%+v, %+v) and betterAddr(%+v, %+v) both unexpectedly true", tt.a, tt.b, tt.b, tt.a)
}
}
}
func epStrings(eps []tailcfg.Endpoint) (ret []string) {
for _, ep := range eps {
ret = append(ret, ep.Addr.String())
}
return
}