x/net/ipv4: add concurrent read/write test

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/165490043

ipv4/readwrite_test.go

@@ -0,0 +1,170 @@
+// 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.
+
+package ipv4_test
+
+import (
+	"bytes"
+	"net"
+	"runtime"
+	"sync"
+	"testing"
+
+	"golang.org/x/net/internal/nettest"
+	"golang.org/x/net/ipv4"
+)
+
+func benchmarkUDPListener() (net.PacketConn, net.Addr, error) {
+	c, err := net.ListenPacket("udp4", "127.0.0.1:0")
+	if err != nil {
+		return nil, nil, err
+	}
+	dst, err := net.ResolveUDPAddr("udp4", c.LocalAddr().String())
+	if err != nil {
+		c.Close()
+		return nil, nil, err
+	}
+	return c, dst, nil
+}
+
+func BenchmarkReadWriteNetUDP(b *testing.B) {
+	c, dst, err := benchmarkUDPListener()
+	if err != nil {
+		b.Fatalf("benchmarkUDPListener failed: %v", err)
+	}
+	defer c.Close()
+
+	wb, rb := []byte("HELLO-R-U-THERE"), make([]byte, 128)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchmarkReadWriteNetUDP(b, c, wb, rb, dst)
+	}
+}
+
+func benchmarkReadWriteNetUDP(b *testing.B, c net.PacketConn, wb, rb []byte, dst net.Addr) {
+	if _, err := c.WriteTo(wb, dst); err != nil {
+		b.Fatalf("net.PacketConn.WriteTo failed: %v", err)
+	}
+	if _, _, err := c.ReadFrom(rb); err != nil {
+		b.Fatalf("net.PacketConn.ReadFrom failed: %v", err)
+	}
+}
+
+func BenchmarkReadWriteIPv4UDP(b *testing.B) {
+	c, dst, err := benchmarkUDPListener()
+	if err != nil {
+		b.Fatalf("benchmarkUDPListener failed: %v", err)
+	}
+	defer c.Close()
+
+	p := ipv4.NewPacketConn(c)
+	defer p.Close()
+	cf := ipv4.FlagTTL | ipv4.FlagInterface
+	if err := p.SetControlMessage(cf, true); err != nil {
+		b.Fatalf("ipv4.PacketConn.SetControlMessage failed: %v", err)
+	}
+	ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagLoopback)
+
+	wb, rb := []byte("HELLO-R-U-THERE"), make([]byte, 128)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		benchmarkReadWriteIPv4UDP(b, p, wb, rb, dst, ifi)
+	}
+}
+
+func benchmarkReadWriteIPv4UDP(b *testing.B, p *ipv4.PacketConn, wb, rb []byte, dst net.Addr, ifi *net.Interface) {
+	cm := ipv4.ControlMessage{TTL: 1}
+	if ifi != nil {
+		cm.IfIndex = ifi.Index
+	}
+	if n, err := p.WriteTo(wb, &cm, dst); err != nil {
+		b.Fatalf("ipv4.PacketConn.WriteTo failed: %v", err)
+	} else if n != len(wb) {
+		b.Fatalf("ipv4.PacketConn.WriteTo failed: short write: %v", n)
+	}
+	if _, _, _, err := p.ReadFrom(rb); err != nil {
+		b.Fatalf("ipv4.PacketConn.ReadFrom failed: %v", err)
+	}
+}
+
+func TestPacketConnConcurrentReadWriteUnicastUDP(t *testing.T) {
+	switch runtime.GOOS {
+	case "nacl", "plan9", "solaris", "windows":
+		t.Skipf("not supported on %q", runtime.GOOS)
+	}
+
+	c, err := net.ListenPacket("udp4", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	p := ipv4.NewPacketConn(c)
+	defer p.Close()
+
+	dst, err := net.ResolveUDPAddr("udp4", c.LocalAddr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagLoopback)
+	cf := ipv4.FlagTTL | ipv4.FlagSrc | ipv4.FlagDst | ipv4.FlagInterface
+	wb := []byte("HELLO-R-U-THERE")
+
+	if err := p.SetControlMessage(cf, true); err != nil { // probe before test
+		if nettest.ProtocolNotSupported(err) {
+			t.Skipf("not supported on %q", runtime.GOOS)
+		}
+		t.Fatalf("ipv4.PacketConn.SetControlMessage failed: %v", err)
+	}
+
+	var wg sync.WaitGroup
+	reader := func() {
+		defer wg.Done()
+		rb := make([]byte, 128)
+		if n, cm, _, err := p.ReadFrom(rb); err != nil {
+			t.Error(err)
+			return
+		} else if !bytes.Equal(rb[:n], wb) {
+			t.Errorf("got %v; want %v", rb[:n], wb)
+			return
+		} else {
+			t.Logf("rcvd cmsg: %v", cm)
+		}
+	}
+	writer := func(toggle bool) {
+		defer wg.Done()
+		cm := ipv4.ControlMessage{
+			Src: net.IPv4(127, 0, 0, 1),
+		}
+		if ifi != nil {
+			cm.IfIndex = ifi.Index
+		}
+		if err := p.SetControlMessage(cf, toggle); err != nil {
+			t.Error(err)
+			return
+		}
+		if n, err := p.WriteTo(wb, &cm, dst); err != nil {
+			t.Error(err)
+			return
+		} else if n != len(wb) {
+			t.Errorf("short write: %v", n)
+			return
+		}
+	}
+
+	const N = 10
+	wg.Add(N)
+	for i := 0; i < N; i++ {
+		go reader()
+	}
+	wg.Add(2 * N)
+	for i := 0; i < 2*N; i++ {
+		go writer(i%2 != 0)
+	}
+	wg.Add(N)
+	for i := 0; i < N; i++ {
+		go reader()
+	}
+	wg.Wait()
+}

ipv4/unicast_test.go

@@ -17,77 +17,6 @@ import (
 	"golang.org/x/net/ipv4"
 )
 
-func benchmarkUDPListener() (net.PacketConn, net.Addr, error) {
-	c, err := net.ListenPacket("udp4", "127.0.0.1:0")
-	if err != nil {
-		return nil, nil, err
-	}
-	dst, err := net.ResolveUDPAddr("udp4", c.LocalAddr().String())
-	if err != nil {
-		c.Close()
-		return nil, nil, err
-	}
-	return c, dst, nil
-}
-
-func BenchmarkReadWriteNetUDP(b *testing.B) {
-	c, dst, err := benchmarkUDPListener()
-	if err != nil {
-		b.Fatalf("benchmarkUDPListener failed: %v", err)
-	}
-	defer c.Close()
-
-	wb, rb := []byte("HELLO-R-U-THERE"), make([]byte, 128)
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		benchmarkReadWriteNetUDP(b, c, wb, rb, dst)
-	}
-}
-
-func benchmarkReadWriteNetUDP(b *testing.B, c net.PacketConn, wb, rb []byte, dst net.Addr) {
-	if _, err := c.WriteTo(wb, dst); err != nil {
-		b.Fatalf("net.PacketConn.WriteTo failed: %v", err)
-	}
-	if _, _, err := c.ReadFrom(rb); err != nil {
-		b.Fatalf("net.PacketConn.ReadFrom failed: %v", err)
-	}
-}
-
-func BenchmarkReadWriteIPv4UDP(b *testing.B) {
-	c, dst, err := benchmarkUDPListener()
-	if err != nil {
-		b.Fatalf("benchmarkUDPListener failed: %v", err)
-	}
-	defer c.Close()
-
-	p := ipv4.NewPacketConn(c)
-	defer p.Close()
-	cf := ipv4.FlagTTL | ipv4.FlagInterface
-	if err := p.SetControlMessage(cf, true); err != nil {
-		b.Fatalf("ipv4.PacketConn.SetControlMessage failed: %v", err)
-	}
-	ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagLoopback)
-
-	wb, rb := []byte("HELLO-R-U-THERE"), make([]byte, 128)
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		benchmarkReadWriteIPv4UDP(b, p, wb, rb, dst, ifi)
-	}
-}
-
-func benchmarkReadWriteIPv4UDP(b *testing.B, p *ipv4.PacketConn, wb, rb []byte, dst net.Addr, ifi *net.Interface) {
-	cm := ipv4.ControlMessage{TTL: 1}
-	if ifi != nil {
-		cm.IfIndex = ifi.Index
-	}
-	if _, err := p.WriteTo(wb, &cm, dst); err != nil {
-		b.Fatalf("ipv4.PacketConn.WriteTo failed: %v", err)
-	}
-	if _, _, _, err := p.ReadFrom(rb); err != nil {
-		b.Fatalf("ipv4.PacketConn.ReadFrom failed: %v", err)
-	}
-}
-
 func TestPacketConnReadWriteUnicastUDP(t *testing.T) {
 	switch runtime.GOOS {
 	case "nacl", "plan9", "solaris", "windows":