123 lines
2.5 KiB
Go
123 lines
2.5 KiB
Go
// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build aix || darwin || dragonfly || freebsd || netbsd || openbsd || solaris || windows
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package ipv4
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import (
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"errors"
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"net"
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"unsafe"
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"golang.org/x/net/internal/socket"
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)
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var errNoSuchInterface = errors.New("no such interface")
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func (so *sockOpt) setIPMreq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
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mreq := ipMreq{Multiaddr: [4]byte{grp[0], grp[1], grp[2], grp[3]}}
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if err := setIPMreqInterface(&mreq, ifi); err != nil {
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return err
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}
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b := (*[sizeofIPMreq]byte)(unsafe.Pointer(&mreq))[:sizeofIPMreq]
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return so.Set(c, b)
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}
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func (so *sockOpt) getMulticastIf(c *socket.Conn) (*net.Interface, error) {
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var b [4]byte
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if _, err := so.Get(c, b[:]); err != nil {
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return nil, err
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}
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ifi, err := netIP4ToInterface(net.IPv4(b[0], b[1], b[2], b[3]))
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if err != nil {
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return nil, err
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}
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return ifi, nil
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}
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func (so *sockOpt) setMulticastIf(c *socket.Conn, ifi *net.Interface) error {
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ip, err := netInterfaceToIP4(ifi)
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if err != nil {
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return err
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}
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var b [4]byte
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copy(b[:], ip)
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return so.Set(c, b[:])
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}
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func setIPMreqInterface(mreq *ipMreq, ifi *net.Interface) error {
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if ifi == nil {
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return nil
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}
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ifat, err := ifi.Addrs()
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if err != nil {
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return err
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}
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for _, ifa := range ifat {
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switch ifa := ifa.(type) {
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case *net.IPAddr:
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if ip := ifa.IP.To4(); ip != nil {
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copy(mreq.Interface[:], ip)
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return nil
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}
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case *net.IPNet:
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if ip := ifa.IP.To4(); ip != nil {
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copy(mreq.Interface[:], ip)
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return nil
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}
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}
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}
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return errNoSuchInterface
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}
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func netIP4ToInterface(ip net.IP) (*net.Interface, error) {
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ift, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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for _, ifi := range ift {
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ifat, err := ifi.Addrs()
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if err != nil {
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return nil, err
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}
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for _, ifa := range ifat {
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switch ifa := ifa.(type) {
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case *net.IPAddr:
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if ip.Equal(ifa.IP) {
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return &ifi, nil
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}
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case *net.IPNet:
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if ip.Equal(ifa.IP) {
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return &ifi, nil
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}
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}
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}
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}
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return nil, errNoSuchInterface
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}
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func netInterfaceToIP4(ifi *net.Interface) (net.IP, error) {
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if ifi == nil {
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return net.IPv4zero.To4(), nil
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}
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ifat, err := ifi.Addrs()
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if err != nil {
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return nil, err
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}
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for _, ifa := range ifat {
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switch ifa := ifa.(type) {
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case *net.IPAddr:
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if ip := ifa.IP.To4(); ip != nil {
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return ip, nil
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}
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case *net.IPNet:
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if ip := ifa.IP.To4(); ip != nil {
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return ip, nil
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}
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}
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}
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return nil, errNoSuchInterface
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}
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