x/net/ipv4: add concurrent read/write test
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/165490043
diff --git a/ipv4/readwrite_test.go b/ipv4/readwrite_test.go
new file mode 100644
index 0000000..fbb2082
--- /dev/null
+++ b/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()
+}
