// Copyright 2014 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. package ipv4 import "syscall" const (	// See /usr/include/linux/in.h.	sysSockoptHeaderPrepend      = syscall.IP_HDRINCL	sysSockoptTOS                = syscall.IP_TOS	sysSockoptTTL                = syscall.IP_TTL	sysSockoptMulticastTTL       = syscall.IP_MULTICAST_TTL	sysSockoptMulticastInterface = syscall.IP_MULTICAST_IF	sysSockoptMulticastLoopback  = syscall.IP_MULTICAST_LOOP	sysSockoptJoinGroup          = syscall.IP_ADD_MEMBERSHIP	sysSockoptLeaveGroup         = syscall.IP_DROP_MEMBERSHIP) const (	// See /usr/include/linux/in.h.	sysSockoptReceiveTOS = syscall.IP_RECVTOS	sysSockoptReceiveTTL = syscall.IP_RECVTTL	sysSockoptPacketInfo = syscall.IP_PKTINFO) const (	sysSizeofNewMulticastReq = 0xc	sysSizeofPacketInfo      = 0xc) struct sysNewMulticastReq {	IP        [4]byte	Interface [4]byte	IfIndex   int32} struct sysPacketInfo {	IfIndex  int32	RoutedIP [4]byte	IP       [4]byte} func init() {	supportsPacketInfo = true}