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// 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.
//go: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
}
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