1 // Copyright 2014 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
14 "golang.org/x/net/icmp"
15 "golang.org/x/net/ipv6"
18 func ExampleConn_markingTCP() {
19 ln, err := net.Listen("tcp", "[::]:1024")
32 if c.RemoteAddr().(*net.TCPAddr).IP.To16() != nil && c.RemoteAddr().(*net.TCPAddr).IP.To4() == nil {
34 if err := p.SetTrafficClass(0x28); err != nil { // DSCP AF11
37 if err := p.SetHopLimit(128); err != nil {
41 if _, err := c.Write([]byte("HELLO-R-U-THERE-ACK")); err != nil {
48 func ExamplePacketConn_servingOneShotMulticastDNS() {
49 c, err := net.ListenPacket("udp6", "[::]:5353") // mDNS over UDP
54 p := ipv6.NewPacketConn(c)
56 en0, err := net.InterfaceByName("en0")
60 mDNSLinkLocal := net.UDPAddr{IP: net.ParseIP("ff02::fb")}
61 if err := p.JoinGroup(en0, &mDNSLinkLocal); err != nil {
64 defer p.LeaveGroup(en0, &mDNSLinkLocal)
65 if err := p.SetControlMessage(ipv6.FlagDst|ipv6.FlagInterface, true); err != nil {
69 var wcm ipv6.ControlMessage
70 b := make([]byte, 1500)
72 _, rcm, peer, err := p.ReadFrom(b)
76 if !rcm.Dst.IsMulticast() || !rcm.Dst.Equal(mDNSLinkLocal.IP) {
79 wcm.IfIndex = rcm.IfIndex
80 answers := []byte("FAKE-MDNS-ANSWERS") // fake mDNS answers, you need to implement this
81 if _, err := p.WriteTo(answers, &wcm, peer); err != nil {
87 func ExamplePacketConn_tracingIPPacketRoute() {
88 // Tracing an IP packet route to www.google.com.
90 const host = "www.google.com"
91 ips, err := net.LookupIP(host)
96 for _, ip := range ips {
97 if ip.To16() != nil && ip.To4() == nil {
99 fmt.Printf("using %v for tracing an IP packet route to %s\n", dst.IP, host)
104 log.Fatal("no AAAA record found")
107 c, err := net.ListenPacket("ip6:58", "::") // ICMP for IPv6
112 p := ipv6.NewPacketConn(c)
114 if err := p.SetControlMessage(ipv6.FlagHopLimit|ipv6.FlagSrc|ipv6.FlagDst|ipv6.FlagInterface, true); err != nil {
118 Type: ipv6.ICMPTypeEchoRequest, Code: 0,
120 ID: os.Getpid() & 0xffff,
121 Data: []byte("HELLO-R-U-THERE"),
124 var f ipv6.ICMPFilter
126 f.Accept(ipv6.ICMPTypeTimeExceeded)
127 f.Accept(ipv6.ICMPTypeEchoReply)
128 if err := p.SetICMPFilter(&f); err != nil {
132 var wcm ipv6.ControlMessage
133 rb := make([]byte, 1500)
134 for i := 1; i <= 64; i++ { // up to 64 hops
135 wm.Body.(*icmp.Echo).Seq = i
136 wb, err := wm.Marshal(nil)
141 // In the real world usually there are several
142 // multiple traffic-engineered paths for each hop.
143 // You may need to probe a few times to each hop.
146 if _, err := p.WriteTo(wb, &wcm, &dst); err != nil {
149 if err := p.SetReadDeadline(time.Now().Add(3 * time.Second)); err != nil {
152 n, rcm, peer, err := p.ReadFrom(rb)
154 if err, ok := err.(net.Error); ok && err.Timeout() {
155 fmt.Printf("%v\t*\n", i)
160 rm, err := icmp.ParseMessage(58, rb[:n])
164 rtt := time.Since(begin)
166 // In the real world you need to determine whether the
167 // received message is yours using ControlMessage.Src,
168 // ControlMesage.Dst, icmp.Echo.ID and icmp.Echo.Seq.
170 case ipv6.ICMPTypeTimeExceeded:
171 names, _ := net.LookupAddr(peer.String())
172 fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, rcm)
173 case ipv6.ICMPTypeEchoReply:
174 names, _ := net.LookupAddr(peer.String())
175 fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, rcm)
181 func ExamplePacketConn_advertisingOSPFHello() {
182 c, err := net.ListenPacket("ip6:89", "::") // OSPF for IPv6
187 p := ipv6.NewPacketConn(c)
189 en0, err := net.InterfaceByName("en0")
193 allSPFRouters := net.IPAddr{IP: net.ParseIP("ff02::5")}
194 if err := p.JoinGroup(en0, &allSPFRouters); err != nil {
197 defer p.LeaveGroup(en0, &allSPFRouters)
199 hello := make([]byte, 24) // fake hello data, you need to implement this
200 ospf := make([]byte, 16) // fake ospf header, you need to implement this
201 ospf[0] = 3 // version 3
202 ospf[1] = 1 // hello packet
203 ospf = append(ospf, hello...)
204 if err := p.SetChecksum(true, 12); err != nil {
208 cm := ipv6.ControlMessage{
209 TrafficClass: 0xc0, // DSCP CS6
213 if _, err := p.WriteTo(ospf, &cm, &allSPFRouters); err != nil {