func TestUDPMultiplePacketConnWithMultipleGroupListeners(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}

	for _, gaddr := range udpMultipleGroupListenerTests {
		c1, err := net.ListenPacket("udp6", "[ff02::]:1024") // wildcard address with reusable port
		if err != nil {
			t.Fatal(err)
		}
		defer c1.Close()

		c2, err := net.ListenPacket("udp6", "[ff02::]:1024") // wildcard address with reusable port
		if err != nil {
			t.Fatal(err)
		}
		defer c2.Close()

		var ps [2]*ipv6.PacketConn
		ps[0] = ipv6.NewPacketConn(c1)
		ps[1] = ipv6.NewPacketConn(c2)
		var mift []*net.Interface

		ift, err := net.Interfaces()
		if err != nil {
			t.Fatal(err)
		}
		for i, ifi := range ift {
			if _, ok := nettest.IsMulticastCapable("ip6", &ifi); !ok {
				continue
			}
			for _, p := range ps {
				if err := p.JoinGroup(&ifi, gaddr); err != nil {
					t.Fatal(err)
				}
			}
			mift = append(mift, &ift[i])
		}
		for _, ifi := range mift {
			for _, p := range ps {
				if err := p.LeaveGroup(ifi, gaddr); err != nil {
					t.Fatal(err)
				}
			}
		}
	}
}

func TestPacketConnMulticastSocketOptions(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
	if ifi == nil {
		t.Skipf("not available on %s", runtime.GOOS)
	}

	m, ok := nettest.SupportsRawIPSocket()
	for _, tt := range packetConnMulticastSocketOptionTests {
		if tt.net == "ip6" && !ok {
			t.Log(m)
			continue
		}
		c, err := net.ListenPacket(tt.net+tt.proto, tt.addr)
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()
		p := ipv6.NewPacketConn(c)
		defer p.Close()

		if tt.src == nil {
			testMulticastSocketOptions(t, p, ifi, tt.grp)
		} else {
			testSourceSpecificMulticastSocketOptions(t, p, ifi, tt.grp, tt.src)
		}
	}
}

func TestSetICMPFilter(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}

	c, err := net.ListenPacket("ip6:ipv6-icmp", "::1")
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()

	p := ipv6.NewPacketConn(c)

	var f ipv6.ICMPFilter
	f.SetAll(true)
	f.Accept(ipv6.ICMPTypeEchoRequest)
	f.Accept(ipv6.ICMPTypeEchoReply)
	if err := p.SetICMPFilter(&f); err != nil {
		t.Fatal(err)
	}
	kf, err := p.ICMPFilter()
	if err != nil {
		t.Fatal(err)
	}
	if !reflect.DeepEqual(kf, &f) {
		t.Fatalf("got %#v; want %#v", kf, f)
	}
}

// setInterface is used to set the query interface, uses sytem
// default if not provided
func (c *client) setInterface(iface *net.Interface) error {
	p := ipv4.NewPacketConn(c.ipv4UnicastConn)
	if err := p.SetMulticastInterface(iface); err != nil {
		return err
	}
	p2 := ipv6.NewPacketConn(c.ipv6UnicastConn)
	if err := p2.SetMulticastInterface(iface); err != nil {
		return err
	}
	p = ipv4.NewPacketConn(c.ipv4MulticastConn)
	if err := p.SetMulticastInterface(iface); err != nil {
		return err
	}
	p2 = ipv6.NewPacketConn(c.ipv6MulticastConn)
	if err := p2.SetMulticastInterface(iface); err != nil {
		return err
	}
	return nil
}

func TestIPPerInterfaceSinglePacketConnWithSingleGroupListener(t *testing.T) {
	switch runtime.GOOS {
	case "darwin", "dragonfly", "openbsd": // platforms that return fe80::1%lo0: bind: can't assign requested address
		t.Skipf("not supported on %s", runtime.GOOS)
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}

	gaddr := net.IPAddr{IP: net.ParseIP("ff02::114")} // see RFC 4727
	type ml struct {
		c   *ipv6.PacketConn
		ifi *net.Interface
	}
	var mlt []*ml

	ift, err := net.Interfaces()
	if err != nil {
		t.Fatal(err)
	}
	for i, ifi := range ift {
		ip, ok := nettest.IsMulticastCapable("ip6", &ifi)
		if !ok {
			continue
		}
		c, err := net.ListenPacket("ip6:ipv6-icmp", fmt.Sprintf("%s%%%s", ip.String(), ifi.Name)) // unicast address
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()
		p := ipv6.NewPacketConn(c)
		if err := p.JoinGroup(&ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
		mlt = append(mlt, &ml{p, &ift[i]})
	}
	for _, m := range mlt {
		if err := m.c.LeaveGroup(m.ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
	}
}

func TestUDPPerInterfaceSinglePacketConnWithSingleGroupListener(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}

	gaddr := net.IPAddr{IP: net.ParseIP("ff02::114")} // see RFC 4727
	type ml struct {
		c   *ipv6.PacketConn
		ifi *net.Interface
	}
	var mlt []*ml

	ift, err := net.Interfaces()
	if err != nil {
		t.Fatal(err)
	}
	for i, ifi := range ift {
		ip, ok := nettest.IsMulticastCapable("ip6", &ifi)
		if !ok {
			continue
		}
		c, err := net.ListenPacket("udp6", fmt.Sprintf("[%s%%%s]:1024", ip.String(), ifi.Name)) // unicast address with non-reusable port
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()
		p := ipv6.NewPacketConn(c)
		if err := p.JoinGroup(&ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
		mlt = append(mlt, &ml{p, &ift[i]})
	}
	for _, m := range mlt {
		if err := m.c.LeaveGroup(m.ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
	}
}

func TestIPSinglePacketConnWithSingleGroupListener(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}

	c, err := net.ListenPacket("ip6:ipv6-icmp", "::") // wildcard address
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()

	p := ipv6.NewPacketConn(c)
	gaddr := net.IPAddr{IP: net.ParseIP("ff02::114")} // see RFC 4727
	var mift []*net.Interface

	ift, err := net.Interfaces()
	if err != nil {
		t.Fatal(err)
	}
	for i, ifi := range ift {
		if _, ok := nettest.IsMulticastCapable("ip6", &ifi); !ok {
			continue
		}
		if err := p.JoinGroup(&ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
		mift = append(mift, &ift[i])
	}
	for _, ifi := range mift {
		if err := p.LeaveGroup(ifi, &gaddr); err != nil {
			t.Fatal(err)
		}
	}
}

func ExamplePacketConn_servingOneShotMulticastDNS() {
	c, err := net.ListenPacket("udp6", "[::]:5353") // mDNS over UDP
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)

	en0, err := net.InterfaceByName("en0")
	if err != nil {
		log.Fatal(err)
	}
	mDNSLinkLocal := net.UDPAddr{IP: net.ParseIP("ff02::fb")}
	if err := p.JoinGroup(en0, &mDNSLinkLocal); err != nil {
		log.Fatal(err)
	}
	defer p.LeaveGroup(en0, &mDNSLinkLocal)
	if err := p.SetControlMessage(ipv6.FlagDst|ipv6.FlagInterface, true); err != nil {
		log.Fatal(err)
	}

	var wcm ipv6.ControlMessage
	b := make([]byte, 1500)
	for {
		_, rcm, peer, err := p.ReadFrom(b)
		if err != nil {
			log.Fatal(err)
		}
		if !rcm.Dst.IsMulticast() || !rcm.Dst.Equal(mDNSLinkLocal.IP) {
			continue
		}
		wcm.IfIndex = rcm.IfIndex
		answers := []byte("FAKE-MDNS-ANSWERS") // fake mDNS answers, you need to implement this
		if _, err := p.WriteTo(answers, &wcm, peer); err != nil {
			log.Fatal(err)
		}
	}
}

func TestPacketConnChecksum(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}

	c, err := net.ListenPacket(fmt.Sprintf("ip6:%d", iana.ProtocolOSPFIGP), "::") // OSPF for IPv6
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()

	p := ipv6.NewPacketConn(c)
	offset := 12 // see RFC 5340

	for _, toggle := range []bool{false, true} {
		if err := p.SetChecksum(toggle, offset); err != nil {
			if toggle {
				t.Fatalf("ipv6.PacketConn.SetChecksum(%v, %v) failed: %v", toggle, offset, err)
			} else {
				// Some platforms never allow to disable the kernel
				// checksum processing.
				t.Logf("ipv6.PacketConn.SetChecksum(%v, %v) failed: %v", toggle, offset, err)
			}
		}
		if on, offset, err := p.Checksum(); err != nil {
			t.Fatal(err)
		} else {
			t.Logf("kernel checksum processing enabled=%v, offset=%v", on, offset)
		}
	}
}

func ExamplePacketConn_advertisingOSPFHello() {
	c, err := net.ListenPacket(fmt.Sprintf("ip6:%d", iana.ProtocolOSPFIGP), "::") // OSPF for IPv6
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)

	en0, err := net.InterfaceByName("en0")
	if err != nil {
		log.Fatal(err)
	}
	allSPFRouters := net.IPAddr{IP: net.ParseIP("ff02::5")}
	if err := p.JoinGroup(en0, &allSPFRouters); err != nil {
		log.Fatal(err)
	}
	defer p.LeaveGroup(en0, &allSPFRouters)

	hello := make([]byte, 24) // fake hello data, you need to implement this
	ospf := make([]byte, 16)  // fake ospf header, you need to implement this
	ospf[0] = 3               // version 3
	ospf[1] = 1               // hello packet
	ospf = append(ospf, hello...)
	if err := p.SetChecksum(true, 12); err != nil {
		log.Fatal(err)
	}

	cm := ipv6.ControlMessage{
		TrafficClass: iana.DiffServCS6,
		HopLimit:     1,
		IfIndex:      en0.Index,
	}
	if _, err := p.WriteTo(ospf, &cm, &allSPFRouters); err != nil {
		log.Fatal(err)
	}
}

func BenchmarkReadWriteIPv6UDP(b *testing.B) {
	if !supportsIPv6 {
		b.Skip("ipv6 is not supported")
	}

	c, dst, err := benchmarkUDPListener()
	if err != nil {
		b.Fatal(err)
	}
	defer c.Close()

	p := ipv6.NewPacketConn(c)
	cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU
	if err := p.SetControlMessage(cf, true); err != nil {
		b.Fatal(err)
	}
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagLoopback)

	wb, rb := []byte("HELLO-R-U-THERE"), make([]byte, 128)
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		benchmarkReadWriteIPv6UDP(b, p, wb, rb, dst, ifi)
	}
}

func TestPacketConnUnicastSocketOptions(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}

	m, ok := nettest.SupportsRawIPSocket()
	for _, tt := range packetConnUnicastSocketOptionTests {
		if tt.net == "ip6" && !ok {
			t.Log(m)
			continue
		}
		c, err := net.ListenPacket(tt.net+tt.proto, tt.addr)
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()

		testUnicastSocketOptions(t, ipv6.NewPacketConn(c))
	}
}

func ExamplePacketConn_tracingIPPacketRoute() {
	// Tracing an IP packet route to www.google.com.

	const host = "www.google.com"
	ips, err := net.LookupIP(host)
	if err != nil {
		log.Fatal(err)
	}
	var dst net.IPAddr
	for _, ip := range ips {
		if ip.To16() != nil && ip.To4() == nil {
			dst.IP = ip
			fmt.Printf("using %v for tracing an IP packet route to %s\n", dst.IP, host)
			break
		}
	}
	if dst.IP == nil {
		log.Fatal("no AAAA record found")
	}

	c, err := net.ListenPacket(fmt.Sprintf("ip6:%d", iana.ProtocolIPv6ICMP), "::") // ICMP for IPv6
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)

	if err := p.SetControlMessage(ipv6.FlagHopLimit|ipv6.FlagSrc|ipv6.FlagDst|ipv6.FlagInterface, true); err != nil {
		log.Fatal(err)
	}
	wm := icmp.Message{
		Type: ipv6.ICMPTypeEchoRequest, Code: 0,
		Body: &icmp.Echo{
			ID:   os.Getpid() & 0xffff,
			Data: []byte("HELLO-R-U-THERE"),
		},
	}
	var f ipv6.ICMPFilter
	f.SetAll(true)
	f.Accept(ipv6.ICMPTypeTimeExceeded)
	f.Accept(ipv6.ICMPTypeEchoReply)
	if err := p.SetICMPFilter(&f); err != nil {
		log.Fatal(err)
	}

	var wcm ipv6.ControlMessage
	rb := make([]byte, 1500)
	for i := 1; i <= 64; i++ { // up to 64 hops
		wm.Body.(*icmp.Echo).Seq = i
		wb, err := wm.Marshal(nil)
		if err != nil {
			log.Fatal(err)
		}

		// In the real world usually there are several
		// multiple traffic-engineered paths for each hop.
		// You may need to probe a few times to each hop.
		begin := time.Now()
		wcm.HopLimit = i
		if _, err := p.WriteTo(wb, &wcm, &dst); err != nil {
			log.Fatal(err)
		}
		if err := p.SetReadDeadline(time.Now().Add(3 * time.Second)); err != nil {
			log.Fatal(err)
		}
		n, rcm, peer, err := p.ReadFrom(rb)
		if err != nil {
			if err, ok := err.(net.Error); ok && err.Timeout() {
				fmt.Printf("%v\t*\n", i)
				continue
			}
			log.Fatal(err)
		}
		rm, err := icmp.ParseMessage(iana.ProtocolIPv6ICMP, rb[:n])
		if err != nil {
			log.Fatal(err)
		}
		rtt := time.Since(begin)

		// In the real world you need to determine whether the
		// received message is yours using ControlMessage.Src,
		// ControlMesage.Dst, icmp.Echo.ID and icmp.Echo.Seq.
		switch rm.Type {
		case ipv6.ICMPTypeTimeExceeded:
			names, _ := net.LookupAddr(peer.String())
			fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, rcm)
		case ipv6.ICMPTypeEchoReply:
			names, _ := net.LookupAddr(peer.String())
			fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, rcm)
			return
		}
	}
}

func TestPacketConnConcurrentReadWriteUnicastUDP(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}

	c, err := net.ListenPacket("udp6", "[::1]:0")
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)
	defer p.Close()

	dst, err := net.ResolveUDPAddr("udp6", c.LocalAddr().String())
	if err != nil {
		t.Fatal(err)
	}

	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagLoopback)
	cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU
	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 := ipv6.ControlMessage{
			TrafficClass: iana.DiffServAF11 | iana.CongestionExperienced,
			Src:          net.IPv6loopback,
		}
		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("got %v; want %v", n, len(wb))
			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()
}

func TestPacketConnReadWriteMulticastUDP(t *testing.T) {
	switch runtime.GOOS {
	case "freebsd": // due to a bug on loopback marking
		// See http://www.freebsd.org/cgi/query-pr.cgi?pr=180065.
		t.Skipf("not supported on %s", runtime.GOOS)
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
	if ifi == nil {
		t.Skipf("not available on %s", runtime.GOOS)
	}

	for _, tt := range packetConnReadWriteMulticastUDPTests {
		c, err := net.ListenPacket("udp6", tt.addr)
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()

		grp := *tt.grp
		grp.Port = c.LocalAddr().(*net.UDPAddr).Port
		p := ipv6.NewPacketConn(c)
		defer p.Close()
		if tt.src == nil {
			if err := p.JoinGroup(ifi, &grp); err != nil {
				t.Fatal(err)
			}
			defer p.LeaveGroup(ifi, &grp)
		} else {
			if err := p.JoinSourceSpecificGroup(ifi, &grp, tt.src); err != nil {
				switch runtime.GOOS {
				case "freebsd", "linux":
				default: // platforms that don't support MLDv2 fail here
					t.Logf("not supported on %s", runtime.GOOS)
					continue
				}
				t.Fatal(err)
			}
			defer p.LeaveSourceSpecificGroup(ifi, &grp, tt.src)
		}
		if err := p.SetMulticastInterface(ifi); err != nil {
			t.Fatal(err)
		}
		if _, err := p.MulticastInterface(); err != nil {
			t.Fatal(err)
		}
		if err := p.SetMulticastLoopback(true); err != nil {
			t.Fatal(err)
		}
		if _, err := p.MulticastLoopback(); err != nil {
			t.Fatal(err)
		}

		cm := ipv6.ControlMessage{
			TrafficClass: iana.DiffServAF11 | iana.CongestionExperienced,
			Src:          net.IPv6loopback,
			IfIndex:      ifi.Index,
		}
		cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU
		wb := []byte("HELLO-R-U-THERE")

		for i, toggle := range []bool{true, false, true} {
			if err := p.SetControlMessage(cf, toggle); err != nil {
				if nettest.ProtocolNotSupported(err) {
					t.Logf("not supported on %s", runtime.GOOS)
					continue
				}
				t.Fatal(err)
			}
			if err := p.SetDeadline(time.Now().Add(200 * time.Millisecond)); err != nil {
				t.Fatal(err)
			}
			cm.HopLimit = i + 1
			if n, err := p.WriteTo(wb, &cm, &grp); err != nil {
				t.Fatal(err)
			} else if n != len(wb) {
				t.Fatal(err)
			}
			rb := make([]byte, 128)
			if n, cm, _, err := p.ReadFrom(rb); err != nil {
				t.Fatal(err)
			} else if !bytes.Equal(rb[:n], wb) {
				t.Fatalf("got %v; want %v", rb[:n], wb)
			} else {
				t.Logf("rcvd cmsg: %v", cm)
			}
		}
	}
}

func TestPacketConnReadWriteMulticastICMP(t *testing.T) {
	switch runtime.GOOS {
	case "freebsd": // due to a bug on loopback marking
		// See http://www.freebsd.org/cgi/query-pr.cgi?pr=180065.
		t.Skipf("not supported on %s", runtime.GOOS)
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
	if ifi == nil {
		t.Skipf("not available on %s", runtime.GOOS)
	}

	for _, tt := range packetConnReadWriteMulticastICMPTests {
		c, err := net.ListenPacket("ip6:ipv6-icmp", "::")
		if err != nil {
			t.Fatal(err)
		}
		defer c.Close()

		pshicmp := icmp.IPv6PseudoHeader(c.LocalAddr().(*net.IPAddr).IP, tt.grp.IP)
		p := ipv6.NewPacketConn(c)
		defer p.Close()
		if tt.src == nil {
			if err := p.JoinGroup(ifi, tt.grp); err != nil {
				t.Fatal(err)
			}
			defer p.LeaveGroup(ifi, tt.grp)
		} else {
			if err := p.JoinSourceSpecificGroup(ifi, tt.grp, tt.src); err != nil {
				switch runtime.GOOS {
				case "freebsd", "linux":
				default: // platforms that don't support MLDv2 fail here
					t.Logf("not supported on %s", runtime.GOOS)
					continue
				}
				t.Fatal(err)
			}
			defer p.LeaveSourceSpecificGroup(ifi, tt.grp, tt.src)
		}
		if err := p.SetMulticastInterface(ifi); err != nil {
			t.Fatal(err)
		}
		if _, err := p.MulticastInterface(); err != nil {
			t.Fatal(err)
		}
		if err := p.SetMulticastLoopback(true); err != nil {
			t.Fatal(err)
		}
		if _, err := p.MulticastLoopback(); err != nil {
			t.Fatal(err)
		}

		cm := ipv6.ControlMessage{
			TrafficClass: iana.DiffServAF11 | iana.CongestionExperienced,
			Src:          net.IPv6loopback,
			IfIndex:      ifi.Index,
		}
		cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU

		var f ipv6.ICMPFilter
		f.SetAll(true)
		f.Accept(ipv6.ICMPTypeEchoReply)
		if err := p.SetICMPFilter(&f); err != nil {
			t.Fatal(err)
		}

		var psh []byte
		for i, toggle := range []bool{true, false, true} {
			if toggle {
				psh = nil
				if err := p.SetChecksum(true, 2); err != nil {
					t.Fatal(err)
				}
			} else {
				psh = pshicmp
				// Some platforms never allow to
				// disable the kernel checksum
				// processing.
				p.SetChecksum(false, -1)
			}
			wb, err := (&icmp.Message{
				Type: ipv6.ICMPTypeEchoRequest, Code: 0,
				Body: &icmp.Echo{
					ID: os.Getpid() & 0xffff, Seq: i + 1,
					Data: []byte("HELLO-R-U-THERE"),
				},
			}).Marshal(psh)
			if err != nil {
				t.Fatal(err)
			}
			if err := p.SetControlMessage(cf, toggle); err != nil {
				if nettest.ProtocolNotSupported(err) {
					t.Logf("not supported on %s", runtime.GOOS)
//.........这里部分代码省略.........

func TestPacketConnReadWriteUnicastICMP(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}
	if m, ok := nettest.SupportsRawIPSocket(); !ok {
		t.Skip(m)
	}

	c, err := net.ListenPacket("ip6:ipv6-icmp", "::1")
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)
	defer p.Close()

	dst, err := net.ResolveIPAddr("ip6", "::1")
	if err != nil {
		t.Fatal(err)
	}

	pshicmp := icmp.IPv6PseudoHeader(c.LocalAddr().(*net.IPAddr).IP, dst.IP)
	cm := ipv6.ControlMessage{
		TrafficClass: iana.DiffServAF11 | iana.CongestionExperienced,
		Src:          net.IPv6loopback,
	}
	cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagLoopback)
	if ifi != nil {
		cm.IfIndex = ifi.Index
	}

	var f ipv6.ICMPFilter
	f.SetAll(true)
	f.Accept(ipv6.ICMPTypeEchoReply)
	if err := p.SetICMPFilter(&f); err != nil {
		t.Fatal(err)
	}

	var psh []byte
	for i, toggle := range []bool{true, false, true} {
		if toggle {
			psh = nil
			if err := p.SetChecksum(true, 2); err != nil {
				t.Fatal(err)
			}
		} else {
			psh = pshicmp
			// Some platforms never allow to disable the
			// kernel checksum processing.
			p.SetChecksum(false, -1)
		}
		wb, err := (&icmp.Message{
			Type: ipv6.ICMPTypeEchoRequest, Code: 0,
			Body: &icmp.Echo{
				ID: os.Getpid() & 0xffff, Seq: i + 1,
				Data: []byte("HELLO-R-U-THERE"),
			},
		}).Marshal(psh)
		if err != nil {
			t.Fatal(err)
		}
		if err := p.SetControlMessage(cf, toggle); err != nil {
			if nettest.ProtocolNotSupported(err) {
				t.Skipf("not supported on %s", runtime.GOOS)
			}
			t.Fatal(err)
		}
		cm.HopLimit = i + 1
		if err := p.SetWriteDeadline(time.Now().Add(100 * time.Millisecond)); err != nil {
			t.Fatal(err)
		}
		if n, err := p.WriteTo(wb, &cm, dst); err != nil {
			t.Fatal(err)
		} else if n != len(wb) {
			t.Fatalf("got %v; want %v", n, len(wb))
		}
		rb := make([]byte, 128)
		if err := p.SetReadDeadline(time.Now().Add(100 * time.Millisecond)); err != nil {
			t.Fatal(err)
		}
		if n, cm, _, err := p.ReadFrom(rb); err != nil {
			switch runtime.GOOS {
			case "darwin": // older darwin kernels have some limitation on receiving icmp packet through raw socket
				t.Logf("not supported on %s", runtime.GOOS)
				continue
			}
			t.Fatal(err)
		} else {
			t.Logf("rcvd cmsg: %v", cm)
			if m, err := icmp.ParseMessage(iana.ProtocolIPv6ICMP, rb[:n]); err != nil {
				t.Fatal(err)
			} else if m.Type != ipv6.ICMPTypeEchoReply || m.Code != 0 {
				t.Fatalf("got type=%v, code=%v; want type=%v, code=%v", m.Type, m.Code, ipv6.ICMPTypeEchoReply, 0)
			}
		}
//.........这里部分代码省略.........

func TestPacketConnReadWriteUnicastUDP(t *testing.T) {
	switch runtime.GOOS {
	case "nacl", "plan9", "solaris", "windows":
		t.Skipf("not supported on %s", runtime.GOOS)
	}
	if !supportsIPv6 {
		t.Skip("ipv6 is not supported")
	}

	c, err := net.ListenPacket("udp6", "[::1]:0")
	if err != nil {
		t.Fatal(err)
	}
	defer c.Close()
	p := ipv6.NewPacketConn(c)
	defer p.Close()

	dst, err := net.ResolveUDPAddr("udp6", c.LocalAddr().String())
	if err != nil {
		t.Fatal(err)
	}

	cm := ipv6.ControlMessage{
		TrafficClass: iana.DiffServAF11 | iana.CongestionExperienced,
		Src:          net.IPv6loopback,
	}
	cf := ipv6.FlagTrafficClass | ipv6.FlagHopLimit | ipv6.FlagSrc | ipv6.FlagDst | ipv6.FlagInterface | ipv6.FlagPathMTU
	ifi := nettest.RoutedInterface("ip6", net.FlagUp|net.FlagLoopback)
	if ifi != nil {
		cm.IfIndex = ifi.Index
	}
	wb := []byte("HELLO-R-U-THERE")

	for i, toggle := range []bool{true, false, true} {
		if err := p.SetControlMessage(cf, toggle); err != nil {
			if nettest.ProtocolNotSupported(err) {
				t.Skipf("not supported on %s", runtime.GOOS)
			}
			t.Fatal(err)
		}
		cm.HopLimit = i + 1
		if err := p.SetWriteDeadline(time.Now().Add(100 * time.Millisecond)); err != nil {
			t.Fatal(err)
		}
		if n, err := p.WriteTo(wb, &cm, dst); err != nil {
			t.Fatal(err)
		} else if n != len(wb) {
			t.Fatalf("got %v; want %v", n, len(wb))
		}
		rb := make([]byte, 128)
		if err := p.SetReadDeadline(time.Now().Add(100 * time.Millisecond)); err != nil {
			t.Fatal(err)
		}
		if n, cm, _, err := p.ReadFrom(rb); err != nil {
			t.Fatal(err)
		} else if !bytes.Equal(rb[:n], wb) {
			t.Fatalf("got %v; want %v", rb[:n], wb)
		} else {
			t.Logf("rcvd cmsg: %v", cm)
		}
	}
}