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// Copyright 2011 The Go 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 net
import (
"bufio"
"context"
"internal/poll"
"internal/testenv"
"io"
"runtime"
"sync"
"testing"
"time"
)
var prohibitionaryDialArgTests = []struct {
network string
address string
}{
{"tcp6", "127.0.0.1"},
{"tcp6", "::ffff:127.0.0.1"},
}
func TestProhibitionaryDialArg(t *testing.T) {
testenv.MustHaveExternalNetwork(t)
switch runtime.GOOS {
case "plan9":
t.Skipf("not supported on %s", runtime.GOOS)
}
if !supportsIPv4map() {
t.Skip("mapping ipv4 address inside ipv6 address not supported")
}
ln, err := Listen("tcp", "[::]:0")
if err != nil {
t.Fatal(err)
}
defer ln.Close()
_, port, err := SplitHostPort(ln.Addr().String())
if err != nil {
t.Fatal(err)
}
for i, tt := range prohibitionaryDialArgTests {
c, err := Dial(tt.network, JoinHostPort(tt.address, port))
if err == nil {
c.Close()
t.Errorf("#%d: %v", i, err)
}
}
}
func TestDialLocal(t *testing.T) {
ln, err := newLocalListener("tcp")
if err != nil {
t.Fatal(err)
}
defer ln.Close()
_, port, err := SplitHostPort(ln.Addr().String())
if err != nil {
t.Fatal(err)
}
c, err := Dial("tcp", JoinHostPort("", port))
if err != nil {
t.Fatal(err)
}
c.Close()
}
func TestDialerDualStackFDLeak(t *testing.T) {
switch runtime.GOOS {
case "plan9":
t.Skipf("%s does not have full support of socktest", runtime.GOOS)
case "windows":
t.Skipf("not implemented a way to cancel dial racers in TCP SYN-SENT state on %s", runtime.GOOS)
case "openbsd":
testenv.SkipFlaky(t, 15157)
}
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
closedPortDelay, expectClosedPortDelay := dialClosedPort()
if closedPortDelay > expectClosedPortDelay {
t.Errorf("got %v; want <= %v", closedPortDelay, expectClosedPortDelay)
}
before := sw.Sockets()
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
testHookLookupIP = lookupLocalhost
handler := func(dss *dualStackServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
dss, err := newDualStackServer()
if err != nil {
t.Fatal(err)
}
if err := dss.buildup(handler); err != nil {
dss.teardown()
t.Fatal(err)
}
const N = 10
var wg sync.WaitGroup
wg.Add(N)
d := &Dialer{DualStack: true, Timeout: 100*time.Millisecond + closedPortDelay}
for i := 0; i < N; i++ {
go func() {
defer wg.Done()
c, err := d.Dial("tcp", JoinHostPort("localhost", dss.port))
if err != nil {
t.Error(err)
return
}
c.Close()
}()
}
wg.Wait()
dss.teardown()
after := sw.Sockets()
if len(after) != len(before) {
t.Errorf("got %d; want %d", len(after), len(before))
}
}
// Define a pair of blackholed (IPv4, IPv6) addresses, for which dialTCP is
// expected to hang until the timeout elapses. These addresses are reserved
// for benchmarking by RFC 6890.
const (
slowDst4 = "198.18.0.254"
slowDst6 = "2001:2::254"
)
// In some environments, the slow IPs may be explicitly unreachable, and fail
// more quickly than expected. This test hook prevents dialTCP from returning
// before the deadline.
func slowDialTCP(ctx context.Context, net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
c, err := doDialTCP(ctx, net, laddr, raddr)
if ParseIP(slowDst4).Equal(raddr.IP) || ParseIP(slowDst6).Equal(raddr.IP) {
// Wait for the deadline, or indefinitely if none exists.
<-ctx.Done()
}
return c, err
}
func dialClosedPort() (actual, expected time.Duration) {
// Estimate the expected time for this platform.
// On Windows, dialing a closed port takes roughly 1 second,
// but other platforms should be instantaneous.
if runtime.GOOS == "windows" {
expected = 1500 * time.Millisecond
} else {
expected = 95 * time.Millisecond
}
l, err := Listen("tcp", "127.0.0.1:0")
if err != nil {
return 999 * time.Hour, expected
}
addr := l.Addr().String()
l.Close()
// On OpenBSD, interference from TestSelfConnect is mysteriously
// causing the first attempt to hang for a few seconds, so we throw
// away the first result and keep the second.
for i := 1; ; i++ {
startTime := time.Now()
c, err := Dial("tcp", addr)
if err == nil {
c.Close()
}
elapsed := time.Now().Sub(startTime)
if i == 2 {
return elapsed, expected
}
}
}
func TestDialParallel(t *testing.T) {
testenv.MustHaveExternalNetwork(t)
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
closedPortDelay, expectClosedPortDelay := dialClosedPort()
if closedPortDelay > expectClosedPortDelay {
t.Errorf("got %v; want <= %v", closedPortDelay, expectClosedPortDelay)
}
const instant time.Duration = 0
const fallbackDelay = 200 * time.Millisecond
// Some cases will run quickly when "connection refused" is fast,
// or trigger the fallbackDelay on Windows. This value holds the
// lesser of the two delays.
var closedPortOrFallbackDelay time.Duration
if closedPortDelay < fallbackDelay {
closedPortOrFallbackDelay = closedPortDelay
} else {
closedPortOrFallbackDelay = fallbackDelay
}
origTestHookDialTCP := testHookDialTCP
defer func() { testHookDialTCP = origTestHookDialTCP }()
testHookDialTCP = slowDialTCP
nCopies := func(s string, n int) []string {
out := make([]string, n)
for i := 0; i < n; i++ {
out[i] = s
}
return out
}
var testCases = []struct {
primaries []string
fallbacks []string
teardownNetwork string
expectOk bool
expectElapsed time.Duration
}{
// These should just work on the first try.
{[]string{"127.0.0.1"}, []string{}, "", true, instant},
{[]string{"::1"}, []string{}, "", true, instant},
{[]string{"127.0.0.1", "::1"}, []string{slowDst6}, "tcp6", true, instant},
{[]string{"::1", "127.0.0.1"}, []string{slowDst4}, "tcp4", true, instant},
// Primary is slow; fallback should kick in.
{[]string{slowDst4}, []string{"::1"}, "", true, fallbackDelay},
// Skip a "connection refused" in the primary thread.
{[]string{"127.0.0.1", "::1"}, []string{}, "tcp4", true, closedPortDelay},
{[]string{"::1", "127.0.0.1"}, []string{}, "tcp6", true, closedPortDelay},
// Skip a "connection refused" in the fallback thread.
{[]string{slowDst4, slowDst6}, []string{"::1", "127.0.0.1"}, "tcp6", true, fallbackDelay + closedPortDelay},
// Primary refused, fallback without delay.
{[]string{"127.0.0.1"}, []string{"::1"}, "tcp4", true, closedPortOrFallbackDelay},
{[]string{"::1"}, []string{"127.0.0.1"}, "tcp6", true, closedPortOrFallbackDelay},
// Everything is refused.
{[]string{"127.0.0.1"}, []string{}, "tcp4", false, closedPortDelay},
// Nothing to do; fail instantly.
{[]string{}, []string{}, "", false, instant},
// Connecting to tons of addresses should not trip the deadline.
{nCopies("::1", 1000), []string{}, "", true, instant},
}
handler := func(dss *dualStackServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
// Convert a list of IP strings into TCPAddrs.
makeAddrs := func(ips []string, port string) addrList {
var out addrList
for _, ip := range ips {
addr, err := ResolveTCPAddr("tcp", JoinHostPort(ip, port))
if err != nil {
t.Fatal(err)
}
out = append(out, addr)
}
return out
}
for i, tt := range testCases {
dss, err := newDualStackServer()
if err != nil {
t.Fatal(err)
}
defer dss.teardown()
if err := dss.buildup(handler); err != nil {
t.Fatal(err)
}
if tt.teardownNetwork != "" {
// Destroy one of the listening sockets, creating an unreachable port.
dss.teardownNetwork(tt.teardownNetwork)
}
primaries := makeAddrs(tt.primaries, dss.port)
fallbacks := makeAddrs(tt.fallbacks, dss.port)
d := Dialer{
FallbackDelay: fallbackDelay,
}
startTime := time.Now()
dp := &dialParam{
Dialer: d,
network: "tcp",
address: "?",
}
c, err := dialParallel(context.Background(), dp, primaries, fallbacks)
elapsed := time.Since(startTime)
if c != nil {
c.Close()
}
if tt.expectOk && err != nil {
t.Errorf("#%d: got %v; want nil", i, err)
} else if !tt.expectOk && err == nil {
t.Errorf("#%d: got nil; want non-nil", i)
}
expectElapsedMin := tt.expectElapsed - 95*time.Millisecond
expectElapsedMax := tt.expectElapsed + 95*time.Millisecond
if !(elapsed >= expectElapsedMin) {
t.Errorf("#%d: got %v; want >= %v", i, elapsed, expectElapsedMin)
} else if !(elapsed <= expectElapsedMax) {
t.Errorf("#%d: got %v; want <= %v", i, elapsed, expectElapsedMax)
}
// Repeat each case, ensuring that it can be canceled quickly.
ctx, cancel := context.WithCancel(context.Background())
var wg sync.WaitGroup
wg.Add(1)
go func() {
time.Sleep(5 * time.Millisecond)
cancel()
wg.Done()
}()
startTime = time.Now()
c, err = dialParallel(ctx, dp, primaries, fallbacks)
if c != nil {
c.Close()
}
elapsed = time.Now().Sub(startTime)
if elapsed > 100*time.Millisecond {
t.Errorf("#%d (cancel): got %v; want <= 100ms", i, elapsed)
}
wg.Wait()
}
}
func lookupSlowFast(ctx context.Context, fn func(context.Context, string) ([]IPAddr, error), host string) ([]IPAddr, error) {
switch host {
case "slow6loopback4":
// Returns a slow IPv6 address, and a local IPv4 address.
return []IPAddr{
{IP: ParseIP(slowDst6)},
{IP: ParseIP("127.0.0.1")},
}, nil
default:
return fn(ctx, host)
}
}
func TestDialerFallbackDelay(t *testing.T) {
testenv.MustHaveExternalNetwork(t)
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
testHookLookupIP = lookupSlowFast
origTestHookDialTCP := testHookDialTCP
defer func() { testHookDialTCP = origTestHookDialTCP }()
testHookDialTCP = slowDialTCP
var testCases = []struct {
dualstack bool
delay time.Duration
expectElapsed time.Duration
}{
// Use a very brief delay, which should fallback immediately.
{true, 1 * time.Nanosecond, 0},
// Use a 200ms explicit timeout.
{true, 200 * time.Millisecond, 200 * time.Millisecond},
// The default is 300ms.
{true, 0, 300 * time.Millisecond},
}
handler := func(dss *dualStackServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
dss, err := newDualStackServer()
if err != nil {
t.Fatal(err)
}
defer dss.teardown()
if err := dss.buildup(handler); err != nil {
t.Fatal(err)
}
for i, tt := range testCases {
d := &Dialer{DualStack: tt.dualstack, FallbackDelay: tt.delay}
startTime := time.Now()
c, err := d.Dial("tcp", JoinHostPort("slow6loopback4", dss.port))
elapsed := time.Now().Sub(startTime)
if err == nil {
c.Close()
} else if tt.dualstack {
t.Error(err)
}
expectMin := tt.expectElapsed - 1*time.Millisecond
expectMax := tt.expectElapsed + 95*time.Millisecond
if !(elapsed >= expectMin) {
t.Errorf("#%d: got %v; want >= %v", i, elapsed, expectMin)
}
if !(elapsed <= expectMax) {
t.Errorf("#%d: got %v; want <= %v", i, elapsed, expectMax)
}
}
}
func TestDialParallelSpuriousConnection(t *testing.T) {
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
var wg sync.WaitGroup
wg.Add(2)
handler := func(dss *dualStackServer, ln Listener) {
// Accept one connection per address.
c, err := ln.Accept()
if err != nil {
t.Fatal(err)
}
// The client should close itself, without sending data.
c.SetReadDeadline(time.Now().Add(1 * time.Second))
var b [1]byte
if _, err := c.Read(b[:]); err != io.EOF {
t.Errorf("got %v; want %v", err, io.EOF)
}
c.Close()
wg.Done()
}
dss, err := newDualStackServer()
if err != nil {
t.Fatal(err)
}
defer dss.teardown()
if err := dss.buildup(handler); err != nil {
t.Fatal(err)
}
const fallbackDelay = 100 * time.Millisecond
origTestHookDialTCP := testHookDialTCP
defer func() { testHookDialTCP = origTestHookDialTCP }()
testHookDialTCP = func(ctx context.Context, net string, laddr, raddr *TCPAddr) (*TCPConn, error) {
// Sleep long enough for Happy Eyeballs to kick in, and inhibit cancelation.
// This forces dialParallel to juggle two successful connections.
time.Sleep(fallbackDelay * 2)
// Now ignore the provided context (which will be canceled) and use a
// different one to make sure this completes with a valid connection,
// which we hope to be closed below:
return doDialTCP(context.Background(), net, laddr, raddr)
}
d := Dialer{
FallbackDelay: fallbackDelay,
}
dp := &dialParam{
Dialer: d,
network: "tcp",
address: "?",
}
makeAddr := func(ip string) addrList {
addr, err := ResolveTCPAddr("tcp", JoinHostPort(ip, dss.port))
if err != nil {
t.Fatal(err)
}
return addrList{addr}
}
// dialParallel returns one connection (and closes the other.)
c, err := dialParallel(context.Background(), dp, makeAddr("127.0.0.1"), makeAddr("::1"))
if err != nil {
t.Fatal(err)
}
c.Close()
// The server should've seen both connections.
wg.Wait()
}
func TestDialerPartialDeadline(t *testing.T) {
now := time.Date(2000, time.January, 1, 0, 0, 0, 0, time.UTC)
var testCases = []struct {
now time.Time
deadline time.Time
addrs int
expectDeadline time.Time
expectErr error
}{
// Regular division.
{now, now.Add(12 * time.Second), 1, now.Add(12 * time.Second), nil},
{now, now.Add(12 * time.Second), 2, now.Add(6 * time.Second), nil},
{now, now.Add(12 * time.Second), 3, now.Add(4 * time.Second), nil},
// Bump against the 2-second sane minimum.
{now, now.Add(12 * time.Second), 999, now.Add(2 * time.Second), nil},
// Total available is now below the sane minimum.
{now, now.Add(1900 * time.Millisecond), 999, now.Add(1900 * time.Millisecond), nil},
// Null deadline.
{now, noDeadline, 1, noDeadline, nil},
// Step the clock forward and cross the deadline.
{now.Add(-1 * time.Millisecond), now, 1, now, nil},
{now.Add(0 * time.Millisecond), now, 1, noDeadline, poll.ErrTimeout},
{now.Add(1 * time.Millisecond), now, 1, noDeadline, poll.ErrTimeout},
}
for i, tt := range testCases {
deadline, err := partialDeadline(tt.now, tt.deadline, tt.addrs)
if err != tt.expectErr {
t.Errorf("#%d: got %v; want %v", i, err, tt.expectErr)
}
if !deadline.Equal(tt.expectDeadline) {
t.Errorf("#%d: got %v; want %v", i, deadline, tt.expectDeadline)
}
}
}
func TestDialerLocalAddr(t *testing.T) {
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
type test struct {
network, raddr string
laddr Addr
error
}
var tests = []test{
{"tcp4", "127.0.0.1", nil, nil},
{"tcp4", "127.0.0.1", &TCPAddr{}, nil},
{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("0.0.0.0")}, nil},
{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("0.0.0.0").To4()}, nil},
{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("::")}, &AddrError{Err: "some error"}},
{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To4()}, nil},
{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To16()}, nil},
{"tcp4", "127.0.0.1", &TCPAddr{IP: IPv6loopback}, errNoSuitableAddress},
{"tcp4", "127.0.0.1", &UDPAddr{}, &AddrError{Err: "some error"}},
{"tcp4", "127.0.0.1", &UnixAddr{}, &AddrError{Err: "some error"}},
{"tcp6", "::1", nil, nil},
{"tcp6", "::1", &TCPAddr{}, nil},
{"tcp6", "::1", &TCPAddr{IP: ParseIP("0.0.0.0")}, nil},
{"tcp6", "::1", &TCPAddr{IP: ParseIP("0.0.0.0").To4()}, nil},
{"tcp6", "::1", &TCPAddr{IP: ParseIP("::")}, nil},
{"tcp6", "::1", &TCPAddr{IP: ParseIP("127.0.0.1").To4()}, errNoSuitableAddress},
{"tcp6", "::1", &TCPAddr{IP: ParseIP("127.0.0.1").To16()}, errNoSuitableAddress},
{"tcp6", "::1", &TCPAddr{IP: IPv6loopback}, nil},
{"tcp6", "::1", &UDPAddr{}, &AddrError{Err: "some error"}},
{"tcp6", "::1", &UnixAddr{}, &AddrError{Err: "some error"}},
{"tcp", "127.0.0.1", nil, nil},
{"tcp", "127.0.0.1", &TCPAddr{}, nil},
{"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("0.0.0.0")}, nil},
{"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("0.0.0.0").To4()}, nil},
{"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To4()}, nil},
{"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To16()}, nil},
{"tcp", "127.0.0.1", &TCPAddr{IP: IPv6loopback}, errNoSuitableAddress},
{"tcp", "127.0.0.1", &UDPAddr{}, &AddrError{Err: "some error"}},
{"tcp", "127.0.0.1", &UnixAddr{}, &AddrError{Err: "some error"}},
{"tcp", "::1", nil, nil},
{"tcp", "::1", &TCPAddr{}, nil},
{"tcp", "::1", &TCPAddr{IP: ParseIP("0.0.0.0")}, nil},
{"tcp", "::1", &TCPAddr{IP: ParseIP("0.0.0.0").To4()}, nil},
{"tcp", "::1", &TCPAddr{IP: ParseIP("::")}, nil},
{"tcp", "::1", &TCPAddr{IP: ParseIP("127.0.0.1").To4()}, errNoSuitableAddress},
{"tcp", "::1", &TCPAddr{IP: ParseIP("127.0.0.1").To16()}, errNoSuitableAddress},
{"tcp", "::1", &TCPAddr{IP: IPv6loopback}, nil},
{"tcp", "::1", &UDPAddr{}, &AddrError{Err: "some error"}},
{"tcp", "::1", &UnixAddr{}, &AddrError{Err: "some error"}},
}
if supportsIPv4map() {
tests = append(tests, test{
"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("::")}, nil,
})
} else {
tests = append(tests, test{
"tcp", "127.0.0.1", &TCPAddr{IP: ParseIP("::")}, &AddrError{Err: "some error"},
})
}
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
testHookLookupIP = lookupLocalhost
handler := func(ls *localServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
var err error
var lss [2]*localServer
for i, network := range []string{"tcp4", "tcp6"} {
lss[i], err = newLocalServer(network)
if err != nil {
t.Fatal(err)
}
defer lss[i].teardown()
if err := lss[i].buildup(handler); err != nil {
t.Fatal(err)
}
}
for _, tt := range tests {
d := &Dialer{LocalAddr: tt.laddr}
var addr string
ip := ParseIP(tt.raddr)
if ip.To4() != nil {
addr = lss[0].Listener.Addr().String()
}
if ip.To16() != nil && ip.To4() == nil {
addr = lss[1].Listener.Addr().String()
}
c, err := d.Dial(tt.network, addr)
if err == nil && tt.error != nil || err != nil && tt.error == nil {
t.Errorf("%s %v->%s: got %v; want %v", tt.network, tt.laddr, tt.raddr, err, tt.error)
}
if err != nil {
if perr := parseDialError(err); perr != nil {
t.Error(perr)
}
continue
}
c.Close()
}
}
func TestDialerDualStack(t *testing.T) {
testenv.SkipFlaky(t, 13324)
if !supportsIPv4() || !supportsIPv6() {
t.Skip("both IPv4 and IPv6 are required")
}
closedPortDelay, expectClosedPortDelay := dialClosedPort()
if closedPortDelay > expectClosedPortDelay {
t.Errorf("got %v; want <= %v", closedPortDelay, expectClosedPortDelay)
}
origTestHookLookupIP := testHookLookupIP
defer func() { testHookLookupIP = origTestHookLookupIP }()
testHookLookupIP = lookupLocalhost
handler := func(dss *dualStackServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
var timeout = 150*time.Millisecond + closedPortDelay
for _, dualstack := range []bool{false, true} {
dss, err := newDualStackServer()
if err != nil {
t.Fatal(err)
}
defer dss.teardown()
if err := dss.buildup(handler); err != nil {
t.Fatal(err)
}
d := &Dialer{DualStack: dualstack, Timeout: timeout}
for range dss.lns {
c, err := d.Dial("tcp", JoinHostPort("localhost", dss.port))
if err != nil {
t.Error(err)
continue
}
switch addr := c.LocalAddr().(*TCPAddr); {
case addr.IP.To4() != nil:
dss.teardownNetwork("tcp4")
case addr.IP.To16() != nil && addr.IP.To4() == nil:
dss.teardownNetwork("tcp6")
}
c.Close()
}
}
}
func TestDialerKeepAlive(t *testing.T) {
handler := func(ls *localServer, ln Listener) {
for {
c, err := ln.Accept()
if err != nil {
return
}
c.Close()
}
}
ls, err := newLocalServer("tcp")
if err != nil {
t.Fatal(err)
}
defer ls.teardown()
if err := ls.buildup(handler); err != nil {
t.Fatal(err)
}
defer func() { testHookSetKeepAlive = func() {} }()
for _, keepAlive := range []bool{false, true} {
got := false
testHookSetKeepAlive = func() { got = true }
var d Dialer
if keepAlive {
d.KeepAlive = 30 * time.Second
}
c, err := d.Dial("tcp", ls.Listener.Addr().String())
if err != nil {
t.Fatal(err)
}
c.Close()
if got != keepAlive {
t.Errorf("Dialer.KeepAlive = %v: SetKeepAlive called = %v, want %v", d.KeepAlive, got, !got)
}
}
}
func TestDialCancel(t *testing.T) {
switch testenv.Builder() {
case "linux-arm64-buildlet":
t.Skip("skipping on linux-arm64-buildlet; incompatible network config? issue 15191")
case "":
testenv.MustHaveExternalNetwork(t)
}
if runtime.GOOS == "nacl" {
// nacl doesn't have external network access.
t.Skipf("skipping on %s", runtime.GOOS)
}
blackholeIPPort := JoinHostPort(slowDst4, "1234")
if !supportsIPv4() {
blackholeIPPort = JoinHostPort(slowDst6, "1234")
}
ticker := time.NewTicker(10 * time.Millisecond)
defer ticker.Stop()
const cancelTick = 5 // the timer tick we cancel the dial at
const timeoutTick = 100
var d Dialer
cancel := make(chan struct{})
d.Cancel = cancel
errc := make(chan error, 1)
connc := make(chan Conn, 1)
go func() {
if c, err := d.Dial("tcp", blackholeIPPort); err != nil {
errc <- err
} else {
connc <- c
}
}()
ticks := 0
for {
select {
case <-ticker.C:
ticks++
if ticks == cancelTick {
close(cancel)
}
if ticks == timeoutTick {
t.Fatal("timeout waiting for dial to fail")
}
case c := <-connc:
c.Close()
t.Fatal("unexpected successful connection")
case err := <-errc:
if perr := parseDialError(err); perr != nil {
t.Error(perr)
}
if ticks < cancelTick {
t.Fatalf("dial error after %d ticks (%d before cancel sent): %v",
ticks, cancelTick-ticks, err)
}
if oe, ok := err.(*OpError); !ok || oe.Err != errCanceled {
t.Fatalf("dial error = %v (%T); want OpError with Err == errCanceled", err, err)
}
return // success.
}
}
}
func TestCancelAfterDial(t *testing.T) {
if testing.Short() {
t.Skip("avoiding time.Sleep")
}
ln, err := newLocalListener("tcp")
if err != nil {
t.Fatal(err)
}
var wg sync.WaitGroup
wg.Add(1)
defer func() {
ln.Close()
wg.Wait()
}()
// Echo back the first line of each incoming connection.
go func() {
for {
c, err := ln.Accept()
if err != nil {
break
}
rb := bufio.NewReader(c)
line, err := rb.ReadString('\n')
if err != nil {
t.Error(err)
c.Close()
continue
}
if _, err := c.Write([]byte(line)); err != nil {
t.Error(err)
}
c.Close()
}
wg.Done()
}()
try := func() {
cancel := make(chan struct{})
d := &Dialer{Cancel: cancel}
c, err := d.Dial("tcp", ln.Addr().String())
// Immediately after dialing, request cancelation and sleep.
// Before Issue 15078 was fixed, this would cause subsequent operations
// to fail with an i/o timeout roughly 50% of the time.
close(cancel)
time.Sleep(10 * time.Millisecond)
if err != nil {
t.Fatal(err)
}
defer c.Close()
// Send some data to confirm that the connection is still alive.
const message = "echo!\n"
if _, err := c.Write([]byte(message)); err != nil {
t.Fatal(err)
}
// The server should echo the line, and close the connection.
rb := bufio.NewReader(c)
line, err := rb.ReadString('\n')
if err != nil {
t.Fatal(err)
}
if line != message {
t.Errorf("got %q; want %q", line, message)
}
if _, err := rb.ReadByte(); err != io.EOF {
t.Errorf("got %v; want %v", err, io.EOF)
}
}
// This bug manifested about 50% of the time, so try it a few times.
for i := 0; i < 10; i++ {
try()
}
}
// Issue 18806: it should always be possible to net.Dial a
// net.Listener().Addr().String when the listen address was ":n", even
// if the machine has halfway configured IPv6 such that it can bind on
// "::" not connect back to that same address.
func TestDialListenerAddr(t *testing.T) {
if testenv.Builder() == "" {
testenv.MustHaveExternalNetwork(t)
}
ln, err := Listen("tcp", ":0")
if err != nil {
t.Fatal(err)
}
defer ln.Close()
addr := ln.Addr().String()
c, err := Dial("tcp", addr)
if err != nil {
t.Fatalf("for addr %q, dial error: %v", addr, err)
}
c.Close()
}