github.com/roboticscm/goman@v0.0.0-20210203095141-87c07b4a0a55/src/net/interface_freebsd.go (about)

     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("route rib", err)
    18  	}
    19  	msgs, err := syscall.ParseRoutingMessage(tab)
    20  	if err != nil {
    21  		return nil, os.NewSyscallError("route message", 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  				ifmat = append(ifmat, ifma...)
    33  			}
    34  		}
    35  	}
    36  	return ifmat, nil
    37  }
    38  
    39  func newMulticastAddr(ifi *Interface, m *syscall.InterfaceMulticastAddrMessage) ([]Addr, error) {
    40  	sas, err := syscall.ParseRoutingSockaddr(m)
    41  	if err != nil {
    42  		return nil, os.NewSyscallError("route sockaddr", err)
    43  	}
    44  	var ifmat []Addr
    45  	for _, sa := range sas {
    46  		switch sa := sa.(type) {
    47  		case *syscall.SockaddrInet4:
    48  			ifma := &IPAddr{IP: IPv4(sa.Addr[0], sa.Addr[1], sa.Addr[2], sa.Addr[3])}
    49  			ifmat = append(ifmat, ifma.toAddr())
    50  		case *syscall.SockaddrInet6:
    51  			ifma := &IPAddr{IP: make(IP, IPv6len)}
    52  			copy(ifma.IP, sa.Addr[:])
    53  			// NOTE: KAME based IPv6 protocol stack usually embeds
    54  			// the interface index in the interface-local or link-
    55  			// local address as the kernel-internal form.
    56  			if ifma.IP.IsInterfaceLocalMulticast() || ifma.IP.IsLinkLocalMulticast() {
    57  				ifma.IP[2], ifma.IP[3] = 0, 0
    58  			}
    59  			ifmat = append(ifmat, ifma.toAddr())
    60  		}
    61  	}
    62  	return ifmat, nil
    63  }