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.Fatal(err)
} else if n != len(wb) {
b.Fatalf("got %v; want %v", n, len(wb))
}
if _, _, _, err := p.ReadFrom(rb); err != nil {
b.Fatal(err)
}
}
func TestPacketConnConcurrentReadWriteUnicastUDP(t *testing.T) {
switch runtime.GOOS {
case "nacl", "plan9", "solaris", "windows":
t.Skipf("not supported on %s", 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 %s", runtime.GOOS)
}
t.Fatal(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()
}