| // Copyright 2012 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. |
| |
| // +build aix darwin dragonfly freebsd netbsd openbsd solaris windows |
| |
| package ipv4 |
| |
| import ( |
| "errors" |
| "net" |
| "unsafe" |
| |
| "golang.org/x/net/internal/socket" |
| ) |
| |
| var errNoSuchInterface = errors.New("no such interface") |
| |
| func (so *sockOpt) setIPMreq(c *socket.Conn, ifi *net.Interface, grp net.IP) error { |
| mreq := ipMreq{Multiaddr: [4]byte{grp[0], grp[1], grp[2], grp[3]}} |
| if err := setIPMreqInterface(&mreq, ifi); err != nil { |
| return err |
| } |
| b := (*[sizeofIPMreq]byte)(unsafe.Pointer(&mreq))[:sizeofIPMreq] |
| return so.Set(c, b) |
| } |
| |
| func (so *sockOpt) getMulticastIf(c *socket.Conn) (*net.Interface, error) { |
| var b [4]byte |
| if _, err := so.Get(c, b[:]); err != nil { |
| return nil, err |
| } |
| ifi, err := netIP4ToInterface(net.IPv4(b[0], b[1], b[2], b[3])) |
| if err != nil { |
| return nil, err |
| } |
| return ifi, nil |
| } |
| |
| func (so *sockOpt) setMulticastIf(c *socket.Conn, ifi *net.Interface) error { |
| ip, err := netInterfaceToIP4(ifi) |
| if err != nil { |
| return err |
| } |
| var b [4]byte |
| copy(b[:], ip) |
| return so.Set(c, b[:]) |
| } |
| |
| func setIPMreqInterface(mreq *ipMreq, ifi *net.Interface) error { |
| if ifi == nil { |
| return nil |
| } |
| ifat, err := ifi.Addrs() |
| if err != nil { |
| return err |
| } |
| for _, ifa := range ifat { |
| switch ifa := ifa.(type) { |
| case *net.IPAddr: |
| if ip := ifa.IP.To4(); ip != nil { |
| copy(mreq.Interface[:], ip) |
| return nil |
| } |
| case *net.IPNet: |
| if ip := ifa.IP.To4(); ip != nil { |
| copy(mreq.Interface[:], ip) |
| return nil |
| } |
| } |
| } |
| return errNoSuchInterface |
| } |
| |
| func netIP4ToInterface(ip net.IP) (*net.Interface, error) { |
| ift, err := net.Interfaces() |
| if err != nil { |
| return nil, err |
| } |
| for _, ifi := range ift { |
| ifat, err := ifi.Addrs() |
| if err != nil { |
| return nil, err |
| } |
| for _, ifa := range ifat { |
| switch ifa := ifa.(type) { |
| case *net.IPAddr: |
| if ip.Equal(ifa.IP) { |
| return &ifi, nil |
| } |
| case *net.IPNet: |
| if ip.Equal(ifa.IP) { |
| return &ifi, nil |
| } |
| } |
| } |
| } |
| return nil, errNoSuchInterface |
| } |
| |
| func netInterfaceToIP4(ifi *net.Interface) (net.IP, error) { |
| if ifi == nil { |
| return net.IPv4zero.To4(), nil |
| } |
| ifat, err := ifi.Addrs() |
| if err != nil { |
| return nil, err |
| } |
| for _, ifa := range ifat { |
| switch ifa := ifa.(type) { |
| case *net.IPAddr: |
| if ip := ifa.IP.To4(); ip != nil { |
| return ip, nil |
| } |
| case *net.IPNet: |
| if ip := ifa.IP.To4(); ip != nil { |
| return ip, nil |
| } |
| } |
| } |
| return nil, errNoSuchInterface |
| } |