libgo/go/net/interface_freebsd.go

   1 // Copyright 2011 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.
   4
   5 package net
   6
   7 import (
   8         "os"
   9         "syscall"
  10 )
  11
  12 // interfaceMulticastAddrTable returns addresses for a specific
  13 // interface.
  14 func interfaceMulticastAddrTable(ifi *Interface) ([]Addr, error) {
  15         tab, err := syscall.RouteRIB(syscall.NET_RT_IFMALIST, ifi.Index)
  16         if err != nil {
  17                 return nil, os.NewSyscallError("routerib", err)
  18         }
  19         msgs, err := syscall.ParseRoutingMessage(tab)
  20         if err != nil {
  21                 return nil, os.NewSyscallError("parseroutingmessage", err)
  22         }
  23         var ifmat []Addr
  24         for _, m := range msgs {
  25                 switch m := m.(type) {
  26                 case *syscall.InterfaceMulticastAddrMessage:
  27                         if ifi.Index == int(m.Header.Index) {
  28                                 ifma, err := newMulticastAddr(ifi, m)
  29                                 if err != nil {
  30                                         return nil, err
  31                                 }
  32                                 if ifma != nil {
  33                                         ifmat = append(ifmat, ifma)
  34                                 }
  35                         }
  36                 }
  37         }
  38         return ifmat, nil
  39 }
  40
  41 func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) (*IPAddr, error) {
  42         sas, err := syscall.ParseRoutingSockaddr(m)
  43         if err != nil {
  44                 return nil, os.NewSyscallError("parseroutingsockaddr", err)
  45         }
  46         switch sa := sas[syscall.RTAX_IFA].(type) {
  47         case *syscall.SockaddrInet4:
  48                 return &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])}, nil
  49         case *syscall.SockaddrInet6:
  50                 ifma := IPAddr{IP: make(IP, IPv6len)}
  51                 copy(ifma.IP, sa.Addr[:])
  52                 // NOTE: KAME based IPv6 protcol stack usually embeds
  53                 // the interface index in the interface-local or
  54                 // link-local address as the kernel-internal form.
  55                 if ifma.IP.IsInterfaceLocalMulticast() || ifma.IP.IsLinkLocalMulticast() {
  56                         ifma.IP[2], ifma.IP[3] = 0, 0
  57                 }
  58                 return &ifma, nil
  59         default:
  60                 return nil, nil
  61         }
  62 }