Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 825 insertions, 0 deletions

diff --git a/src/net/tcpsock_test.go b/src/net/tcpsock_test.go
new file mode 100644
index 0000000..d6172bc
--- /dev/null
+++ b/src/net/tcpsock_test.go
@@ -0,0 +1,825 @@
+// Copyright 2012 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.
+
+// +build !js
+
+package net
+
+import (
+	"fmt"
+	"internal/testenv"
+	"io"
+	"os"
+	"reflect"
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+)
+
+func BenchmarkTCP4OneShot(b *testing.B) {
+	benchmarkTCP(b, false, false, "127.0.0.1:0")
+}
+
+func BenchmarkTCP4OneShotTimeout(b *testing.B) {
+	benchmarkTCP(b, false, true, "127.0.0.1:0")
+}
+
+func BenchmarkTCP4Persistent(b *testing.B) {
+	benchmarkTCP(b, true, false, "127.0.0.1:0")
+}
+
+func BenchmarkTCP4PersistentTimeout(b *testing.B) {
+	benchmarkTCP(b, true, true, "127.0.0.1:0")
+}
+
+func BenchmarkTCP6OneShot(b *testing.B) {
+	if !supportsIPv6() {
+		b.Skip("ipv6 is not supported")
+	}
+	benchmarkTCP(b, false, false, "[::1]:0")
+}
+
+func BenchmarkTCP6OneShotTimeout(b *testing.B) {
+	if !supportsIPv6() {
+		b.Skip("ipv6 is not supported")
+	}
+	benchmarkTCP(b, false, true, "[::1]:0")
+}
+
+func BenchmarkTCP6Persistent(b *testing.B) {
+	if !supportsIPv6() {
+		b.Skip("ipv6 is not supported")
+	}
+	benchmarkTCP(b, true, false, "[::1]:0")
+}
+
+func BenchmarkTCP6PersistentTimeout(b *testing.B) {
+	if !supportsIPv6() {
+		b.Skip("ipv6 is not supported")
+	}
+	benchmarkTCP(b, true, true, "[::1]:0")
+}
+
+func benchmarkTCP(b *testing.B, persistent, timeout bool, laddr string) {
+	testHookUninstaller.Do(uninstallTestHooks)
+
+	const msgLen = 512
+	conns := b.N
+	numConcurrent := runtime.GOMAXPROCS(-1) * 2
+	msgs := 1
+	if persistent {
+		conns = numConcurrent
+		msgs = b.N / conns
+		if msgs == 0 {
+			msgs = 1
+		}
+		if conns > b.N {
+			conns = b.N
+		}
+	}
+	sendMsg := func(c Conn, buf []byte) bool {
+		n, err := c.Write(buf)
+		if n != len(buf) || err != nil {
+			b.Log(err)
+			return false
+		}
+		return true
+	}
+	recvMsg := func(c Conn, buf []byte) bool {
+		for read := 0; read != len(buf); {
+			n, err := c.Read(buf)
+			read += n
+			if err != nil {
+				b.Log(err)
+				return false
+			}
+		}
+		return true
+	}
+	ln, err := Listen("tcp", laddr)
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer ln.Close()
+	serverSem := make(chan bool, numConcurrent)
+	// Acceptor.
+	go func() {
+		for {
+			c, err := ln.Accept()
+			if err != nil {
+				break
+			}
+			serverSem <- true
+			// Server connection.
+			go func(c Conn) {
+				defer func() {
+					c.Close()
+					<-serverSem
+				}()
+				if timeout {
+					c.SetDeadline(time.Now().Add(time.Hour)) // Not intended to fire.
+				}
+				var buf [msgLen]byte
+				for m := 0; m < msgs; m++ {
+					if !recvMsg(c, buf[:]) || !sendMsg(c, buf[:]) {
+						break
+					}
+				}
+			}(c)
+		}
+	}()
+	clientSem := make(chan bool, numConcurrent)
+	for i := 0; i < conns; i++ {
+		clientSem <- true
+		// Client connection.
+		go func() {
+			defer func() {
+				<-clientSem
+			}()
+			c, err := Dial("tcp", ln.Addr().String())
+			if err != nil {
+				b.Log(err)
+				return
+			}
+			defer c.Close()
+			if timeout {
+				c.SetDeadline(time.Now().Add(time.Hour)) // Not intended to fire.
+			}
+			var buf [msgLen]byte
+			for m := 0; m < msgs; m++ {
+				if !sendMsg(c, buf[:]) || !recvMsg(c, buf[:]) {
+					break
+				}
+			}
+		}()
+	}
+	for i := 0; i < numConcurrent; i++ {
+		clientSem <- true
+		serverSem <- true
+	}
+}
+
+func BenchmarkTCP4ConcurrentReadWrite(b *testing.B) {
+	benchmarkTCPConcurrentReadWrite(b, "127.0.0.1:0")
+}
+
+func BenchmarkTCP6ConcurrentReadWrite(b *testing.B) {
+	if !supportsIPv6() {
+		b.Skip("ipv6 is not supported")
+	}
+	benchmarkTCPConcurrentReadWrite(b, "[::1]:0")
+}
+
+func benchmarkTCPConcurrentReadWrite(b *testing.B, laddr string) {
+	testHookUninstaller.Do(uninstallTestHooks)
+
+	// The benchmark creates GOMAXPROCS client/server pairs.
+	// Each pair creates 4 goroutines: client reader/writer and server reader/writer.
+	// The benchmark stresses concurrent reading and writing to the same connection.
+	// Such pattern is used in net/http and net/rpc.
+
+	b.StopTimer()
+
+	P := runtime.GOMAXPROCS(0)
+	N := b.N / P
+	W := 1000
+
+	// Setup P client/server connections.
+	clients := make([]Conn, P)
+	servers := make([]Conn, P)
+	ln, err := Listen("tcp", laddr)
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer ln.Close()
+	done := make(chan bool)
+	go func() {
+		for p := 0; p < P; p++ {
+			s, err := ln.Accept()
+			if err != nil {
+				b.Error(err)
+				return
+			}
+			servers[p] = s
+		}
+		done <- true
+	}()
+	for p := 0; p < P; p++ {
+		c, err := Dial("tcp", ln.Addr().String())
+		if err != nil {
+			b.Fatal(err)
+		}
+		clients[p] = c
+	}
+	<-done
+
+	b.StartTimer()
+
+	var wg sync.WaitGroup
+	wg.Add(4 * P)
+	for p := 0; p < P; p++ {
+		// Client writer.
+		go func(c Conn) {
+			defer wg.Done()
+			var buf [1]byte
+			for i := 0; i < N; i++ {
+				v := byte(i)
+				for w := 0; w < W; w++ {
+					v *= v
+				}
+				buf[0] = v
+				_, err := c.Write(buf[:])
+				if err != nil {
+					b.Error(err)
+					return
+				}
+			}
+		}(clients[p])
+
+		// Pipe between server reader and server writer.
+		pipe := make(chan byte, 128)
+
+		// Server reader.
+		go func(s Conn) {
+			defer wg.Done()
+			var buf [1]byte
+			for i := 0; i < N; i++ {
+				_, err := s.Read(buf[:])
+				if err != nil {
+					b.Error(err)
+					return
+				}
+				pipe <- buf[0]
+			}
+		}(servers[p])
+
+		// Server writer.
+		go func(s Conn) {
+			defer wg.Done()
+			var buf [1]byte
+			for i := 0; i < N; i++ {
+				v := <-pipe
+				for w := 0; w < W; w++ {
+					v *= v
+				}
+				buf[0] = v
+				_, err := s.Write(buf[:])
+				if err != nil {
+					b.Error(err)
+					return
+				}
+			}
+			s.Close()
+		}(servers[p])
+
+		// Client reader.
+		go func(c Conn) {
+			defer wg.Done()
+			var buf [1]byte
+			for i := 0; i < N; i++ {
+				_, err := c.Read(buf[:])
+				if err != nil {
+					b.Error(err)
+					return
+				}
+			}
+			c.Close()
+		}(clients[p])
+	}
+	wg.Wait()
+}
+
+type resolveTCPAddrTest struct {
+	network       string
+	litAddrOrName string
+	addr          *TCPAddr
+	err           error
+}
+
+var resolveTCPAddrTests = []resolveTCPAddrTest{
+	{"tcp", "127.0.0.1:0", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 0}, nil},
+	{"tcp4", "127.0.0.1:65535", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 65535}, nil},
+
+	{"tcp", "[::1]:0", &TCPAddr{IP: ParseIP("::1"), Port: 0}, nil},
+	{"tcp6", "[::1]:65535", &TCPAddr{IP: ParseIP("::1"), Port: 65535}, nil},
+
+	{"tcp", "[::1%en0]:1", &TCPAddr{IP: ParseIP("::1"), Port: 1, Zone: "en0"}, nil},
+	{"tcp6", "[::1%911]:2", &TCPAddr{IP: ParseIP("::1"), Port: 2, Zone: "911"}, nil},
+
+	{"", "127.0.0.1:0", &TCPAddr{IP: IPv4(127, 0, 0, 1), Port: 0}, nil}, // Go 1.0 behavior
+	{"", "[::1]:0", &TCPAddr{IP: ParseIP("::1"), Port: 0}, nil},         // Go 1.0 behavior
+
+	{"tcp", ":12345", &TCPAddr{Port: 12345}, nil},
+
+	{"http", "127.0.0.1:0", nil, UnknownNetworkError("http")},
+
+	{"tcp", "127.0.0.1:http", &TCPAddr{IP: ParseIP("127.0.0.1"), Port: 80}, nil},
+	{"tcp", "[::ffff:127.0.0.1]:http", &TCPAddr{IP: ParseIP("::ffff:127.0.0.1"), Port: 80}, nil},
+	{"tcp", "[2001:db8::1]:http", &TCPAddr{IP: ParseIP("2001:db8::1"), Port: 80}, nil},
+	{"tcp4", "127.0.0.1:http", &TCPAddr{IP: ParseIP("127.0.0.1"), Port: 80}, nil},
+	{"tcp4", "[::ffff:127.0.0.1]:http", &TCPAddr{IP: ParseIP("127.0.0.1"), Port: 80}, nil},
+	{"tcp6", "[2001:db8::1]:http", &TCPAddr{IP: ParseIP("2001:db8::1"), Port: 80}, nil},
+
+	{"tcp4", "[2001:db8::1]:http", nil, &AddrError{Err: errNoSuitableAddress.Error(), Addr: "2001:db8::1"}},
+	{"tcp6", "127.0.0.1:http", nil, &AddrError{Err: errNoSuitableAddress.Error(), Addr: "127.0.0.1"}},
+	{"tcp6", "[::ffff:127.0.0.1]:http", nil, &AddrError{Err: errNoSuitableAddress.Error(), Addr: "::ffff:127.0.0.1"}},
+}
+
+func TestResolveTCPAddr(t *testing.T) {
+	origTestHookLookupIP := testHookLookupIP
+	defer func() { testHookLookupIP = origTestHookLookupIP }()
+	testHookLookupIP = lookupLocalhost
+
+	for _, tt := range resolveTCPAddrTests {
+		addr, err := ResolveTCPAddr(tt.network, tt.litAddrOrName)
+		if !reflect.DeepEqual(addr, tt.addr) || !reflect.DeepEqual(err, tt.err) {
+			t.Errorf("ResolveTCPAddr(%q, %q) = %#v, %v, want %#v, %v", tt.network, tt.litAddrOrName, addr, err, tt.addr, tt.err)
+			continue
+		}
+		if err == nil {
+			addr2, err := ResolveTCPAddr(addr.Network(), addr.String())
+			if !reflect.DeepEqual(addr2, tt.addr) || err != tt.err {
+				t.Errorf("(%q, %q): ResolveTCPAddr(%q, %q) = %#v, %v, want %#v, %v", tt.network, tt.litAddrOrName, addr.Network(), addr.String(), addr2, err, tt.addr, tt.err)
+			}
+		}
+	}
+}
+
+var tcpListenerNameTests = []struct {
+	net   string
+	laddr *TCPAddr
+}{
+	{"tcp4", &TCPAddr{IP: IPv4(127, 0, 0, 1)}},
+	{"tcp4", &TCPAddr{}},
+	{"tcp4", nil},
+}
+
+func TestTCPListenerName(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+
+	for _, tt := range tcpListenerNameTests {
+		ln, err := ListenTCP(tt.net, tt.laddr)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer ln.Close()
+		la := ln.Addr()
+		if a, ok := la.(*TCPAddr); !ok || a.Port == 0 {
+			t.Fatalf("got %v; expected a proper address with non-zero port number", la)
+		}
+	}
+}
+
+func TestIPv6LinkLocalUnicastTCP(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+
+	if !supportsIPv6() {
+		t.Skip("IPv6 is not supported")
+	}
+
+	for i, tt := range ipv6LinkLocalUnicastTCPTests {
+		ln, err := Listen(tt.network, tt.address)
+		if err != nil {
+			// It might return "LookupHost returned no
+			// suitable address" error on some platforms.
+			t.Log(err)
+			continue
+		}
+		ls, err := (&streamListener{Listener: ln}).newLocalServer()
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer ls.teardown()
+		ch := make(chan error, 1)
+		handler := func(ls *localServer, ln Listener) { ls.transponder(ln, ch) }
+		if err := ls.buildup(handler); err != nil {
+			t.Fatal(err)
+		}
+		if la, ok := ln.Addr().(*TCPAddr); !ok || !tt.nameLookup && la.Zone == "" {
+			t.Fatalf("got %v; expected a proper address with zone identifier", la)
+		}
+
+		c, err := Dial(tt.network, ls.Listener.Addr().String())
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer c.Close()
+		if la, ok := c.LocalAddr().(*TCPAddr); !ok || !tt.nameLookup && la.Zone == "" {
+			t.Fatalf("got %v; expected a proper address with zone identifier", la)
+		}
+		if ra, ok := c.RemoteAddr().(*TCPAddr); !ok || !tt.nameLookup && ra.Zone == "" {
+			t.Fatalf("got %v; expected a proper address with zone identifier", ra)
+		}
+
+		if _, err := c.Write([]byte("TCP OVER IPV6 LINKLOCAL TEST")); err != nil {
+			t.Fatal(err)
+		}
+		b := make([]byte, 32)
+		if _, err := c.Read(b); err != nil {
+			t.Fatal(err)
+		}
+
+		for err := range ch {
+			t.Errorf("#%d: %v", i, err)
+		}
+	}
+}
+
+func TestTCPConcurrentAccept(t *testing.T) {
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
+	ln, err := Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	const N = 10
+	var wg sync.WaitGroup
+	wg.Add(N)
+	for i := 0; i < N; i++ {
+		go func() {
+			for {
+				c, err := ln.Accept()
+				if err != nil {
+					break
+				}
+				c.Close()
+			}
+			wg.Done()
+		}()
+	}
+	attempts := 10 * N
+	fails := 0
+	d := &Dialer{Timeout: 200 * time.Millisecond}
+	for i := 0; i < attempts; i++ {
+		c, err := d.Dial("tcp", ln.Addr().String())
+		if err != nil {
+			fails++
+		} else {
+			c.Close()
+		}
+	}
+	ln.Close()
+	wg.Wait()
+	if fails > attempts/9 { // see issues 7400 and 7541
+		t.Fatalf("too many Dial failed: %v", fails)
+	}
+	if fails > 0 {
+		t.Logf("# of failed Dials: %v", fails)
+	}
+}
+
+func TestTCPReadWriteAllocs(t *testing.T) {
+	switch runtime.GOOS {
+	case "plan9":
+		// The implementation of asynchronous cancelable
+		// I/O on Plan 9 allocates memory.
+		// See net/fd_io_plan9.go.
+		t.Skipf("not supported on %s", runtime.GOOS)
+	}
+
+	ln, err := Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln.Close()
+	var server Conn
+	errc := make(chan error, 1)
+	go func() {
+		var err error
+		server, err = ln.Accept()
+		errc <- err
+	}()
+	client, err := Dial("tcp", ln.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer client.Close()
+	if err := <-errc; err != nil {
+		t.Fatal(err)
+	}
+	defer server.Close()
+
+	var buf [128]byte
+	allocs := testing.AllocsPerRun(1000, func() {
+		_, err := server.Write(buf[:])
+		if err != nil {
+			t.Fatal(err)
+		}
+		_, err = io.ReadFull(client, buf[:])
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+	if allocs > 0 {
+		t.Fatalf("got %v; want 0", allocs)
+	}
+
+	var bufwrt [128]byte
+	ch := make(chan bool)
+	defer close(ch)
+	go func() {
+		for <-ch {
+			_, err := server.Write(bufwrt[:])
+			errc <- err
+		}
+	}()
+	allocs = testing.AllocsPerRun(1000, func() {
+		ch <- true
+		if _, err = io.ReadFull(client, buf[:]); err != nil {
+			t.Fatal(err)
+		}
+		if err := <-errc; err != nil {
+			t.Fatal(err)
+		}
+	})
+	if allocs > 0 {
+		t.Fatalf("got %v; want 0", allocs)
+	}
+}
+
+func TestTCPStress(t *testing.T) {
+	const conns = 2
+	const msgLen = 512
+	msgs := int(1e4)
+	if testing.Short() {
+		msgs = 1e2
+	}
+
+	sendMsg := func(c Conn, buf []byte) bool {
+		n, err := c.Write(buf)
+		if n != len(buf) || err != nil {
+			t.Log(err)
+			return false
+		}
+		return true
+	}
+	recvMsg := func(c Conn, buf []byte) bool {
+		for read := 0; read != len(buf); {
+			n, err := c.Read(buf)
+			read += n
+			if err != nil {
+				t.Log(err)
+				return false
+			}
+		}
+		return true
+	}
+
+	ln, err := Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	done := make(chan bool)
+	// Acceptor.
+	go func() {
+		defer func() {
+			done <- true
+		}()
+		for {
+			c, err := ln.Accept()
+			if err != nil {
+				break
+			}
+			// Server connection.
+			go func(c Conn) {
+				defer c.Close()
+				var buf [msgLen]byte
+				for m := 0; m < msgs; m++ {
+					if !recvMsg(c, buf[:]) || !sendMsg(c, buf[:]) {
+						break
+					}
+				}
+			}(c)
+		}
+	}()
+	for i := 0; i < conns; i++ {
+		// Client connection.
+		go func() {
+			defer func() {
+				done <- true
+			}()
+			c, err := Dial("tcp", ln.Addr().String())
+			if err != nil {
+				t.Log(err)
+				return
+			}
+			defer c.Close()
+			var buf [msgLen]byte
+			for m := 0; m < msgs; m++ {
+				if !sendMsg(c, buf[:]) || !recvMsg(c, buf[:]) {
+					break
+				}
+			}
+		}()
+	}
+	for i := 0; i < conns; i++ {
+		<-done
+	}
+	ln.Close()
+	<-done
+}
+
+func TestTCPSelfConnect(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		// TODO(brainman): do not know why it hangs.
+		t.Skip("known-broken test on windows")
+	}
+
+	ln, err := newLocalListener("tcp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var d Dialer
+	c, err := d.Dial(ln.Addr().Network(), ln.Addr().String())
+	if err != nil {
+		ln.Close()
+		t.Fatal(err)
+	}
+	network := c.LocalAddr().Network()
+	laddr := *c.LocalAddr().(*TCPAddr)
+	c.Close()
+	ln.Close()
+
+	// Try to connect to that address repeatedly.
+	n := 100000
+	if testing.Short() {
+		n = 1000
+	}
+	switch runtime.GOOS {
+	case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd", "plan9", "illumos", "solaris", "windows":
+		// Non-Linux systems take a long time to figure
+		// out that there is nothing listening on localhost.
+		n = 100
+	}
+	for i := 0; i < n; i++ {
+		d.Timeout = time.Millisecond
+		c, err := d.Dial(network, laddr.String())
+		if err == nil {
+			addr := c.LocalAddr().(*TCPAddr)
+			if addr.Port == laddr.Port || addr.IP.Equal(laddr.IP) {
+				t.Errorf("Dial %v should fail", addr)
+			} else {
+				t.Logf("Dial %v succeeded - possibly racing with other listener", addr)
+			}
+			c.Close()
+		}
+	}
+}
+
+// Test that >32-bit reads work on 64-bit systems.
+// On 32-bit systems this tests that maxint reads work.
+func TestTCPBig(t *testing.T) {
+	if !*testTCPBig {
+		t.Skip("test disabled; use -tcpbig to enable")
+	}
+
+	for _, writev := range []bool{false, true} {
+		t.Run(fmt.Sprintf("writev=%v", writev), func(t *testing.T) {
+			ln, err := newLocalListener("tcp")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer ln.Close()
+
+			x := int(1 << 30)
+			x = x*5 + 1<<20 // just over 5 GB on 64-bit, just over 1GB on 32-bit
+			done := make(chan int)
+			go func() {
+				defer close(done)
+				c, err := ln.Accept()
+				if err != nil {
+					t.Error(err)
+					return
+				}
+				buf := make([]byte, x)
+				var n int
+				if writev {
+					var n64 int64
+					n64, err = (&Buffers{buf}).WriteTo(c)
+					n = int(n64)
+				} else {
+					n, err = c.Write(buf)
+				}
+				if n != len(buf) || err != nil {
+					t.Errorf("Write(buf) = %d, %v, want %d, nil", n, err, x)
+				}
+				c.Close()
+			}()
+
+			c, err := Dial("tcp", ln.Addr().String())
+			if err != nil {
+				t.Fatal(err)
+			}
+			buf := make([]byte, x)
+			n, err := io.ReadFull(c, buf)
+			if n != len(buf) || err != nil {
+				t.Errorf("Read(buf) = %d, %v, want %d, nil", n, err, x)
+			}
+			c.Close()
+			<-done
+		})
+	}
+}
+
+func TestCopyPipeIntoTCP(t *testing.T) {
+	ln, err := newLocalListener("tcp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer ln.Close()
+
+	errc := make(chan error, 1)
+	defer func() {
+		if err := <-errc; err != nil {
+			t.Error(err)
+		}
+	}()
+	go func() {
+		c, err := ln.Accept()
+		if err != nil {
+			errc <- err
+			return
+		}
+		defer c.Close()
+
+		buf := make([]byte, 100)
+		n, err := io.ReadFull(c, buf)
+		if err != io.ErrUnexpectedEOF || n != 2 {
+			errc <- fmt.Errorf("got err=%q n=%v; want err=%q n=2", err, n, io.ErrUnexpectedEOF)
+			return
+		}
+
+		errc <- nil
+	}()
+
+	c, err := Dial("tcp", ln.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+
+	errc2 := make(chan error, 1)
+	defer func() {
+		if err := <-errc2; err != nil {
+			t.Error(err)
+		}
+	}()
+
+	defer w.Close()
+
+	go func() {
+		_, err := io.Copy(c, r)
+		errc2 <- err
+	}()
+
+	// Split write into 2 packets. That makes Windows TransmitFile
+	// drop second packet.
+	packet := make([]byte, 1)
+	_, err = w.Write(packet)
+	if err != nil {
+		t.Fatal(err)
+	}
+	time.Sleep(100 * time.Millisecond)
+	_, err = w.Write(packet)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func BenchmarkSetReadDeadline(b *testing.B) {
+	ln, err := newLocalListener("tcp")
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer ln.Close()
+	var serv Conn
+	done := make(chan error)
+	go func() {
+		var err error
+		serv, err = ln.Accept()
+		done <- err
+	}()
+	c, err := Dial("tcp", ln.Addr().String())
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer c.Close()
+	if err := <-done; err != nil {
+		b.Fatal(err)
+	}
+	defer serv.Close()
+	c.SetWriteDeadline(time.Now().Add(2 * time.Hour))
+	deadline := time.Now().Add(time.Hour)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		c.SetReadDeadline(deadline)
+		deadline = deadline.Add(1)
+	}
+}