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.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 A record found")
}
c, err := net.ListenPacket(fmt.Sprintf("ip4:%d", iana.ProtocolICMP), "0.0.0.0") // ICMP for IPv4
if err != nil {
log.Fatal(err)
}
defer c.Close()
p := ipv4.NewPacketConn(c)
if err := p.SetControlMessage(ipv4.FlagTTL|ipv4.FlagSrc|ipv4.FlagDst|ipv4.FlagInterface, true); err != nil {
log.Fatal(err)
}
wm := icmp.Message{
Type: ipv4.ICMPTypeEcho, Code: 0,
Body: &icmp.Echo{
ID: os.Getpid() & 0xffff,
Data: []byte("HELLO-R-U-THERE"),
},
}
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)
}
if err := p.SetTTL(i); 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()
if _, err := p.WriteTo(wb, nil, &dst); err != nil {
log.Fatal(err)
}
if err := p.SetReadDeadline(time.Now().Add(3 * time.Second)); err != nil {
log.Fatal(err)
}
n, cm, 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.ProtocolICMP, 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,
// ControlMessage.Dst, icmp.Echo.ID and icmp.Echo.Seq.
switch rm.Type {
case ipv4.ICMPTypeTimeExceeded:
names, _ := net.LookupAddr(peer.String())
fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, cm)
case ipv4.ICMPTypeEchoReply:
names, _ := net.LookupAddr(peer.String())
fmt.Printf("%d\t%v %+v %v\n\t%+v\n", i, peer, names, rtt, cm)
return
default:
log.Printf("unknown ICMP message: %+v\n", rm)
}
}
}
func TestPacketConnReadWriteUnicastICMP(t *testing.T) {
switch runtime.GOOS {
case "nacl", "plan9", "solaris", "windows":
t.Skipf("not supported on %s", runtime.GOOS)
}
if m, ok := nettest.SupportsRawIPSocket(); !ok {
t.Skip(m)
}
ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagLoopback)
if ifi == nil {
t.Skipf("not available on %s", runtime.GOOS)
}
c, err := net.ListenPacket("ip4:icmp", "0.0.0.0")
if err != nil {
t.Fatal(err)
}
defer c.Close()
dst, err := net.ResolveIPAddr("ip4", "127.0.0.1")
if err != nil {
t.Fatal(err)
}
p := ipv4.NewPacketConn(c)
defer p.Close()
cf := ipv4.FlagTTL | ipv4.FlagDst | ipv4.FlagInterface
for i, toggle := range []bool{true, false, true} {
wb, err := (&icmp.Message{
Type: ipv4.ICMPTypeEcho, Code: 0,
Body: &icmp.Echo{
ID: os.Getpid() & 0xffff, Seq: i + 1,
Data: []byte("HELLO-R-U-THERE"),
},
}).Marshal(nil)
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)
continue
}
t.Fatal(err)
}
p.SetTTL(i + 1)
if err := p.SetWriteDeadline(time.Now().Add(100 * time.Millisecond)); err != nil {
t.Fatal(err)
}
if n, err := p.WriteTo(wb, nil, dst); err != nil {
t.Fatal(err)
} else if n != len(wb) {
t.Fatalf("got %v; want %v", n, len(wb))
}
rb := make([]byte, 128)
loop:
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)
m, err := icmp.ParseMessage(iana.ProtocolICMP, rb[:n])
if err != nil {
t.Fatal(err)
}
if runtime.GOOS == "linux" && m.Type == ipv4.ICMPTypeEcho {
// On Linux we must handle own sent packets.
goto loop
}
if m.Type != ipv4.ICMPTypeEchoReply || m.Code != 0 {
t.Fatalf("got type=%v, code=%v; want type=%v, code=%v", m.Type, m.Code, ipv4.ICMPTypeEchoReply, 0)
}
}
}
}
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)
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, tt.grp); err != nil {
t.Fatal(err)
} else if n != len(wb) {
t.Fatalf("got %v; want %v", n, len(wb))
}
rb := make([]byte, 128)
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)
}
}
}
}
}
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)
}
}
}
}
func TestRawConnReadWriteMulticastICMP(t *testing.T) {
if testing.Short() {
t.Skip("to avoid external network")
}
if m, ok := nettest.SupportsRawIPSocket(); !ok {
t.Skip(m)
}
ifi := nettest.RoutedInterface("ip4", net.FlagUp|net.FlagMulticast|net.FlagLoopback)
if ifi == nil {
t.Skipf("not available on %s", runtime.GOOS)
}
for _, tt := range rawConnReadWriteMulticastICMPTests {
c, err := net.ListenPacket("ip4:icmp", "0.0.0.0")
if err != nil {
t.Fatal(err)
}
defer c.Close()
r, err := ipv4.NewRawConn(c)
if err != nil {
t.Fatal(err)
}
defer r.Close()
if tt.src == nil {
if err := r.JoinGroup(ifi, tt.grp); err != nil {
t.Fatal(err)
}
defer r.LeaveGroup(ifi, tt.grp)
} else {
if err := r.JoinSourceSpecificGroup(ifi, tt.grp, tt.src); err != nil {
switch runtime.GOOS {
case "freebsd", "linux":
default: // platforms that don't support IGMPv2/3 fail here
t.Logf("not supported on %s", runtime.GOOS)
continue
}
t.Fatal(err)
}
defer r.LeaveSourceSpecificGroup(ifi, tt.grp, tt.src)
}
if err := r.SetMulticastInterface(ifi); err != nil {
t.Fatal(err)
}
if _, err := r.MulticastInterface(); err != nil {
t.Fatal(err)
}
if err := r.SetMulticastLoopback(true); err != nil {
t.Fatal(err)
}
if _, err := r.MulticastLoopback(); err != nil {
t.Fatal(err)
}
cf := ipv4.FlagTTL | ipv4.FlagDst | ipv4.FlagInterface
for i, toggle := range []bool{true, false, true} {
wb, err := (&icmp.Message{
Type: ipv4.ICMPTypeEcho, Code: 0,
Body: &icmp.Echo{
ID: os.Getpid() & 0xffff, Seq: i + 1,
Data: []byte("HELLO-R-U-THERE"),
},
}).Marshal(nil)
if err != nil {
t.Fatal(err)
}
wh := &ipv4.Header{
Version: ipv4.Version,
Len: ipv4.HeaderLen,
TOS: i + 1,
TotalLen: ipv4.HeaderLen + len(wb),
Protocol: 1,
Dst: tt.grp.IP,
}
if err := r.SetControlMessage(cf, toggle); err != nil {
if nettest.ProtocolNotSupported(err) {
t.Logf("not supported on %s", runtime.GOOS)
continue
}
t.Fatal(err)
}
if err := r.SetDeadline(time.Now().Add(200 * time.Millisecond)); err != nil {
t.Fatal(err)
}
r.SetMulticastTTL(i + 1)
if err := r.WriteTo(wh, wb, nil); err != nil {
t.Fatal(err)
}
rb := make([]byte, ipv4.HeaderLen+128)
if rh, b, cm, err := r.ReadFrom(rb); err != nil {
t.Fatal(err)
} else {
t.Logf("rcvd cmsg: %v", cm)
m, err := icmp.ParseMessage(iana.ProtocolICMP, b)
if err != nil {
t.Fatal(err)
}
switch {
case (rh.Dst.IsLoopback() || rh.Dst.IsLinkLocalUnicast() || rh.Dst.IsGlobalUnicast()) && m.Type == ipv4.ICMPTypeEchoReply && m.Code == 0: // net.inet.icmp.bmcastecho=1
case rh.Dst.IsMulticast() && m.Type == ipv4.ICMPTypeEcho && m.Code == 0: // net.inet.icmp.bmcastecho=0
default:
t.Fatalf("got type=%v, code=%v; want type=%v, code=%v", m.Type, m.Code, ipv4.ICMPTypeEchoReply, 0)
}
}
}
}
}
func TestPacketConnReadWriteMulticastICMP(t *testing.T) {
switch runtime.GOOS {
case "nacl", "plan9", "solaris", "windows":
t.Skipf("not supported on %s", runtime.GOOS)
}
if m, ok := nettest.SupportsRawIPSocket(); !ok {
t.Skip(m)
}
ifi := nettest.RoutedInterface("ip4", 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("ip4:icmp", "0.0.0.0")
if err != nil {
t.Fatal(err)
}
defer c.Close()
p := ipv4.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 IGMPv2/3 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)
}
cf := ipv4.FlagTTL | ipv4.FlagDst | ipv4.FlagInterface
for i, toggle := range []bool{true, false, true} {
wb, err := (&icmp.Message{
Type: ipv4.ICMPTypeEcho, Code: 0,
Body: &icmp.Echo{
ID: os.Getpid() & 0xffff, Seq: i + 1,
Data: []byte("HELLO-R-U-THERE"),
},
}).Marshal(nil)
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)
continue
}
t.Fatal(err)
}
if err := p.SetDeadline(time.Now().Add(200 * time.Millisecond)); err != nil {
t.Fatal(err)
}
p.SetMulticastTTL(i + 1)
if n, err := p.WriteTo(wb, nil, tt.grp); err != nil {
t.Fatal(err)
} else if n != len(wb) {
t.Fatalf("got %v; want %v", n, len(wb))
}
rb := make([]byte, 128)
if n, cm, _, err := p.ReadFrom(rb); err != nil {
t.Fatal(err)
} else {
t.Logf("rcvd cmsg: %v", cm)
m, err := icmp.ParseMessage(iana.ProtocolICMP, rb[:n])
if err != nil {
t.Fatal(err)
}
switch {
case m.Type == ipv4.ICMPTypeEchoReply && m.Code == 0: // net.inet.icmp.bmcastecho=1
case m.Type == ipv4.ICMPTypeEcho && m.Code == 0: // net.inet.icmp.bmcastecho=0
default:
t.Fatalf("got type=%v, code=%v; want type=%v, code=%v", m.Type, m.Code, ipv4.ICMPTypeEchoReply, 0)
}
}
}
}
}