net: joined group addresses for a specific interface for darwin, freebsd, linux

This CL enables to list the multicast, joined group addresses
for a specific interface by using Interface.MulticastAddrs
method.

R=rsc
CC=golang-dev
https://golang.org/cl/4808062

src/pkg/net/Makefile

@@ -29,6 +29,7 @@ GOFILES_freebsd=\
 	fd.go\
 	file.go\
 	interface_bsd.go\
+	interface_freebsd.go\
 	lookup_unix.go\
 	newpollserver.go\
 	port.go\
@@ -45,6 +46,7 @@ GOFILES_darwin=\
 	fd.go\
 	file.go\
 	interface_bsd.go\
+	interface_darwin.go\
 	lookup_unix.go\
 	newpollserver.go\
 	port.go\

src/pkg/net/interface.go

@@ -79,6 +79,15 @@ func (ifi *Interface) Addrs() ([]Addr, os.Error) {
 	return interfaceAddrTable(ifi.Index)
 }
 
+// MulticastAddrs returns multicast, joined group addresses for
+// a specific interface.
+func (ifi *Interface) MulticastAddrs() ([]Addr, os.Error) {
+	if ifi == nil {
+		return nil, os.NewError("net: invalid interface")
+	}
+	return interfaceMulticastAddrTable(ifi.Index)
+}
+
 // Interfaces returns a list of the systems's network interfaces.
 func Interfaces() ([]Interface, os.Error) {
 	return interfaceTable(0)

src/pkg/net/interface_bsd.go

@@ -148,25 +148,55 @@ func newAddr(m *syscall.InterfaceAddrMessage) ([]Addr, os.Error) {
 	}
 
 	for _, s := range sas {
-		var ifa IPAddr
+
 		switch v := s.(type) {
 		case *syscall.SockaddrInet4:
-			ifa.IP = IPv4(v.Addr[0], v.Addr[1], v.Addr[2], v.Addr[3])
+			ifa := &IPAddr{IP: IPv4(v.Addr[0], v.Addr[1], v.Addr[2], v.Addr[3])}
+			ifat = append(ifat, ifa.toAddr())
 		case *syscall.SockaddrInet6:
-			ifa.IP = make(IP, IPv6len)
+			ifa := &IPAddr{IP: make(IP, IPv6len)}
 			copy(ifa.IP, v.Addr[:])
 			// NOTE: KAME based IPv6 protcol stack usually embeds
 			// the interface index in the interface-local or link-
 			// local address as the kernel-internal form.
-			if ifa.IP.IsLinkLocalUnicast() ||
-				ifa.IP.IsInterfaceLocalMulticast() ||
-				ifa.IP.IsLinkLocalMulticast() {
+			if ifa.IP.IsLinkLocalUnicast() {
 				// remove embedded scope zone ID
 				ifa.IP[2], ifa.IP[3] = 0, 0
 			}
+			ifat = append(ifat, ifa.toAddr())
 		}
-		ifat = append(ifat, ifa.toAddr())
 	}
 
 	return ifat, nil
 }
+
+func newMulticastAddr(m *syscall.InterfaceMulticastAddrMessage) ([]Addr, os.Error) {
+	var ifmat []Addr
+
+	sas, e := syscall.ParseRoutingSockaddr(m)
+	if e != 0 {
+		return nil, os.NewSyscallError("route sockaddr", e)
+	}
+
+	for _, s := range sas {
+		switch v := s.(type) {
+		case *syscall.SockaddrInet4:
+			ifma := &IPAddr{IP: IPv4(v.Addr[0], v.Addr[1], v.Addr[2], v.Addr[3])}
+			ifmat = append(ifmat, ifma.toAddr())
+		case *syscall.SockaddrInet6:
+			ifma := &IPAddr{IP: make(IP, IPv6len)}
+			copy(ifma.IP, v.Addr[:])
+			// NOTE: KAME based IPv6 protcol stack usually embeds
+			// the interface index in the interface-local or link-
+			// local address as the kernel-internal form.
+			if ifma.IP.IsInterfaceLocalMulticast() ||
+				ifma.IP.IsLinkLocalMulticast() {
+				// remove embedded scope zone ID
+				ifma.IP[2], ifma.IP[3] = 0, 0
+			}
+			ifmat = append(ifmat, ifma.toAddr())
+		}
+	}
+
+	return ifmat, nil
+}

src/pkg/net/interface_darwin.go

@@ -0,0 +1,49 @@
+// Copyright 2011 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.
+
+// Network interface identification for Darwin
+
+package net
+
+import (
+	"os"
+	"syscall"
+)
+
+// If the ifindex is zero, interfaceMulticastAddrTable returns
+// addresses for all network interfaces.  Otherwise it returns
+// addresses for a specific interface.
+func interfaceMulticastAddrTable(ifindex int) ([]Addr, os.Error) {
+	var (
+		tab   []byte
+		e     int
+		msgs  []syscall.RoutingMessage
+		ifmat []Addr
+	)
+
+	tab, e = syscall.RouteRIB(syscall.NET_RT_IFLIST2, ifindex)
+	if e != 0 {
+		return nil, os.NewSyscallError("route rib", e)
+	}
+
+	msgs, e = syscall.ParseRoutingMessage(tab)
+	if e != 0 {
+		return nil, os.NewSyscallError("route message", e)
+	}
+
+	for _, m := range msgs {
+		switch v := m.(type) {
+		case *syscall.InterfaceMulticastAddrMessage:
+			if ifindex == 0 || ifindex == int(v.Header.Index) {
+				ifma, err := newMulticastAddr(v)
+				if err != nil {
+					return nil, err
+				}
+				ifmat = append(ifmat, ifma...)
+			}
+		}
+	}
+
+	return ifmat, nil
+}

src/pkg/net/interface_freebsd.go

@@ -0,0 +1,49 @@
+// Copyright 2011 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.
+
+// Network interface identification for FreeBSD
+
+package net
+
+import (
+	"os"
+	"syscall"
+)
+
+// If the ifindex is zero, interfaceMulticastAddrTable returns
+// addresses for all network interfaces.  Otherwise it returns
+// addresses for a specific interface.
+func interfaceMulticastAddrTable(ifindex int) ([]Addr, os.Error) {
+	var (
+		tab   []byte
+		e     int
+		msgs  []syscall.RoutingMessage
+		ifmat []Addr
+	)
+
+	tab, e = syscall.RouteRIB(syscall.NET_RT_IFMALIST, ifindex)
+	if e != 0 {
+		return nil, os.NewSyscallError("route rib", e)
+	}
+
+	msgs, e = syscall.ParseRoutingMessage(tab)
+	if e != 0 {
+		return nil, os.NewSyscallError("route message", e)
+	}
+
+	for _, m := range msgs {
+		switch v := m.(type) {
+		case *syscall.InterfaceMulticastAddrMessage:
+			if ifindex == 0 || ifindex == int(v.Header.Index) {
+				ifma, err := newMulticastAddr(v)
+				if err != nil {
+					return nil, err
+				}
+				ifmat = append(ifmat, ifma...)
+			}
+		}
+	}
+
+	return ifmat, nil
+}

src/pkg/net/interface_linux.go

@@ -7,6 +7,7 @@
 package net
 
 import (
+	"fmt"
 	"os"
 	"syscall"
 	"unsafe"
@@ -102,13 +103,13 @@ func linkFlags(rawFlags uint32) Flags {
 // for a specific interface.
 func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
 	var (
-		ifat4 []Addr
-		ifat6 []Addr
 		tab   []byte
-		msgs4 []syscall.NetlinkMessage
-		msgs6 []syscall.NetlinkMessage
 		e     int
 		err   os.Error
+		ifat4 []Addr
+		ifat6 []Addr
+		msgs4 []syscall.NetlinkMessage
+		msgs6 []syscall.NetlinkMessage
 	)
 
 	tab, e = syscall.NetlinkRIB(syscall.RTM_GETADDR, syscall.AF_INET)
@@ -169,17 +170,102 @@ func newAddr(attrs []syscall.NetlinkRouteAttr, family int) []Addr {
 	for _, a := range attrs {
 		switch a.Attr.Type {
 		case syscall.IFA_ADDRESS:
-			ifa := IPAddr{}
 			switch family {
 			case syscall.AF_INET:
-				ifa.IP = IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3])
+				ifa := &IPAddr{IP: IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3])}
+				ifat = append(ifat, ifa.toAddr())
 			case syscall.AF_INET6:
-				ifa.IP = make(IP, IPv6len)
+				ifa := &IPAddr{IP: make(IP, IPv6len)}
 				copy(ifa.IP, a.Value[:])
+				ifat = append(ifat, ifa.toAddr())
 			}
-			ifat = append(ifat, ifa.toAddr())
 		}
 	}
 
 	return ifat
 }
+
+// If the ifindex is zero, interfaceMulticastAddrTable returns
+// addresses for all network interfaces.  Otherwise it returns
+// addresses for a specific interface.
+func interfaceMulticastAddrTable(ifindex int) ([]Addr, os.Error) {
+	var (
+		ifi    *Interface
+		err    os.Error
+		ifmat4 []Addr
+		ifmat6 []Addr
+	)
+
+	if ifindex > 0 {
+		ifi, err = InterfaceByIndex(ifindex)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	ifmat4, err = parseProcNetIGMP(ifi)
+	if err != nil {
+		return nil, err
+	}
+
+	ifmat6, err = parseProcNetIGMP6(ifi)
+	if err != nil {
+		return nil, err
+	}
+
+	return append(ifmat4, ifmat6...), nil
+}
+
+func parseProcNetIGMP(ifi *Interface) ([]Addr, os.Error) {
+	var (
+		ifmat []Addr
+		name  string
+	)
+
+	fd, err := open("/proc/net/igmp")
+	if err != nil {
+		return nil, err
+	}
+	defer fd.close()
+
+	fd.readLine() // skip first line
+	b := make([]byte, IPv4len)
+	for l, ok := fd.readLine(); ok; l, ok = fd.readLine() {
+		f := getFields(l)
+		switch len(f) {
+		case 4:
+			if ifi == nil || name == ifi.Name {
+				fmt.Sscanf(f[0], "%08x", &b)
+				ifma := IPAddr{IP: IPv4(b[3], b[2], b[1], b[0])}
+				ifmat = append(ifmat, ifma.toAddr())
+			}
+		case 5:
+			name = f[1]
+		}
+	}
+
+	return ifmat, nil
+}
+
+func parseProcNetIGMP6(ifi *Interface) ([]Addr, os.Error) {
+	var ifmat []Addr
+
+	fd, err := open("/proc/net/igmp6")
+	if err != nil {
+		return nil, err
+	}
+	defer fd.close()
+
+	b := make([]byte, IPv6len)
+	for l, ok := fd.readLine(); ok; l, ok = fd.readLine() {
+		f := getFields(l)
+		if ifi == nil || f[1] == ifi.Name {
+			fmt.Sscanf(f[2], "%32x", &b)
+			ifma := IPAddr{IP: IP{b[0], b[1], b[2], b[3], b[4], b[5], b[6], b[7], b[8], b[9], b[10], b[11], b[12], b[13], b[14], b[15]}}
+			ifmat = append(ifmat, ifma.toAddr())
+
+		}
+	}
+
+	return ifmat, nil
+}

src/pkg/net/interface_stub.go

@@ -21,3 +21,10 @@ func interfaceTable(ifindex int) ([]Interface, os.Error) {
 func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
 	return nil, nil
 }
+
+// If the ifindex is zero, interfaceMulticastAddrTable returns
+// addresses for all network interfaces.  Otherwise it returns
+// addresses for a specific interface.
+func interfaceMulticastAddrTable(ifindex int) ([]Addr, os.Error) {
+	return nil, nil
+}

src/pkg/net/interface_test.go

@@ -45,10 +45,17 @@ func TestInterfaces(t *testing.T) {
 		if err != nil {
 			t.Fatalf("Interface.Addrs() failed: %v", err)
 		}
+		ifmat, err := ifi.MulticastAddrs()
+		if err != nil {
+			t.Fatalf("Interface.MulticastAddrs() failed: %v", err)
+		}
 		t.Logf("%q: flags %q, ifindex %v, mtu %v\n", ifi.Name, ifi.Flags.String(), ifi.Index, ifi.MTU)
 		for _, ifa := range ifat {
 			t.Logf("\tinterface address %q\n", ifa.String())
 		}
+		for _, ifma := range ifmat {
+			t.Logf("\tjoined group address %q\n", ifma.String())
+		}
 		t.Logf("\thardware address %q", ifi.HardwareAddr.String())
 	}
 }

src/pkg/net/interface_windows.go

@@ -149,3 +149,10 @@ func interfaceAddrTable(ifindex int) ([]Addr, os.Error) {
 	}
 	return ifat, nil
 }
+
+// If the ifindex is zero, interfaceMulticastAddrTable returns
+// addresses for all network interfaces.  Otherwise it returns
+// addresses for a specific interface.
+func interfaceMulticastAddrTable(ifindex int) ([]Addr, os.Error) {
+	return nil, nil
+}