mirror of
https://git.zx2c4.com/wireguard-go
synced 2025-10-31 03:46:20 +08:00
647 lines
13 KiB
Go
647 lines
13 KiB
Go
/* SPDX-License-Identifier: GPL-2.0
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*
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* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*
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* This implements userspace semantics of "sticky sockets", modeled after
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* WireGuard's kernelspace implementation. This is more or less a straight port
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* of the sticky-sockets.c example code:
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* https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
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*
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* Currently there is no way to achieve this within the net package:
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* See e.g. https://github.com/golang/go/issues/17930
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* So this code is remains platform dependent.
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*/
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package main
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import (
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"errors"
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"golang.org/x/sys/unix"
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"net"
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"strconv"
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"unsafe"
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)
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type IPv4Source struct {
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src [4]byte
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ifindex int32
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}
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type IPv6Source struct {
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src [16]byte
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//ifindex belongs in dst.ZoneId
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}
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type NativeEndpoint struct {
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dst [unsafe.Sizeof(unix.SockaddrInet6{})]byte
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src [unsafe.Sizeof(IPv6Source{})]byte
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isV6 bool
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}
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func (endpoint *NativeEndpoint) src4() *IPv4Source {
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return (*IPv4Source)(unsafe.Pointer(&endpoint.src[0]))
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}
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func (endpoint *NativeEndpoint) src6() *IPv6Source {
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return (*IPv6Source)(unsafe.Pointer(&endpoint.src[0]))
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}
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func (endpoint *NativeEndpoint) dst4() *unix.SockaddrInet4 {
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return (*unix.SockaddrInet4)(unsafe.Pointer(&endpoint.dst[0]))
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}
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func (endpoint *NativeEndpoint) dst6() *unix.SockaddrInet6 {
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return (*unix.SockaddrInet6)(unsafe.Pointer(&endpoint.dst[0]))
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}
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type NativeBind struct {
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sock4 int
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sock6 int
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netlinkSock int
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lastEndpoint *NativeEndpoint
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lastMark uint32
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}
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var _ Endpoint = (*NativeEndpoint)(nil)
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var _ Bind = (*NativeBind)(nil)
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func CreateEndpoint(s string) (Endpoint, error) {
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var end NativeEndpoint
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addr, err := parseEndpoint(s)
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if err != nil {
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return nil, err
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}
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ipv4 := addr.IP.To4()
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if ipv4 != nil {
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dst := end.dst4()
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end.isV6 = false
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dst.Port = addr.Port
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copy(dst.Addr[:], ipv4)
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end.ClearSrc()
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return &end, nil
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}
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ipv6 := addr.IP.To16()
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if ipv6 != nil {
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zone, err := zoneToUint32(addr.Zone)
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if err != nil {
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return nil, err
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}
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dst := end.dst6()
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end.isV6 = true
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dst.Port = addr.Port
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dst.ZoneId = zone
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copy(dst.Addr[:], ipv6[:])
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end.ClearSrc()
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return &end, nil
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}
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return nil, errors.New("Invalid IP address")
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}
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func createNetlinkRouteSocket() (int, error) {
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sock, err := unix.Socket(unix.AF_NETLINK, unix.SOCK_RAW, unix.NETLINK_ROUTE)
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if err != nil {
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return -1, err
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}
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saddr := &unix.SockaddrNetlink{
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Family: unix.AF_NETLINK,
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Groups: uint32(1 << (unix.RTNLGRP_IPV4_ROUTE - 1)),
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}
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err = unix.Bind(sock, saddr)
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if err != nil {
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unix.Close(sock)
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return -1, err
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}
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return sock, nil
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}
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func CreateBind(port uint16) (*NativeBind, uint16, error) {
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var err error
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var bind NativeBind
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bind.netlinkSock, err = createNetlinkRouteSocket()
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if err != nil {
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return nil, 0, err
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}
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go bind.routineRouteListener()
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bind.sock6, port, err = create6(port)
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if err != nil {
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unix.Close(bind.netlinkSock)
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return nil, port, err
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}
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bind.sock4, port, err = create4(port)
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if err != nil {
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unix.Close(bind.netlinkSock)
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unix.Close(bind.sock6)
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}
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return &bind, port, err
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}
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func (bind *NativeBind) SetMark(value uint32) error {
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err := unix.SetsockoptInt(
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bind.sock6,
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unix.SOL_SOCKET,
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unix.SO_MARK,
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int(value),
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)
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if err != nil {
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return err
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}
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err = unix.SetsockoptInt(
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bind.sock4,
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unix.SOL_SOCKET,
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unix.SO_MARK,
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int(value),
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)
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if err != nil {
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return err
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}
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bind.lastMark = value
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return nil
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}
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func closeUnblock(fd int) error {
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// shutdown to unblock readers
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unix.Shutdown(fd, unix.SHUT_RD)
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return unix.Close(fd)
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}
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func (bind *NativeBind) Close() error {
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err1 := closeUnblock(bind.sock6)
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err2 := closeUnblock(bind.sock4)
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err3 := closeUnblock(bind.netlinkSock)
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if err1 != nil {
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return err1
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}
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if err2 != nil {
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return err2
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}
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return err3
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}
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func (bind *NativeBind) ReceiveIPv6(buff []byte) (int, Endpoint, error) {
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var end NativeEndpoint
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n, err := receive6(
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bind.sock6,
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buff,
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&end,
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)
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return n, &end, err
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}
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func (bind *NativeBind) ReceiveIPv4(buff []byte) (int, Endpoint, error) {
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var end NativeEndpoint
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n, err := receive4(
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bind.sock4,
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buff,
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&end,
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)
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bind.lastEndpoint = &end
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return n, &end, err
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}
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func (bind *NativeBind) Send(buff []byte, end Endpoint) error {
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nend := end.(*NativeEndpoint)
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if !nend.isV6 {
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return send4(bind.sock4, nend, buff)
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} else {
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return send6(bind.sock6, nend, buff)
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}
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}
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func rawAddrToIP4(addr *unix.SockaddrInet4) net.IP {
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return net.IPv4(
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addr.Addr[0],
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addr.Addr[1],
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addr.Addr[2],
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addr.Addr[3],
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)
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}
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func rawAddrToIP6(addr *unix.SockaddrInet6) net.IP {
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return addr.Addr[:]
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}
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func (end *NativeEndpoint) SrcIP() net.IP {
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if !end.isV6 {
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return net.IPv4(
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end.src4().src[0],
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end.src4().src[1],
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end.src4().src[2],
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end.src4().src[3],
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)
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} else {
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return end.src6().src[:]
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}
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}
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func (end *NativeEndpoint) DstIP() net.IP {
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if !end.isV6 {
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return net.IPv4(
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end.dst4().Addr[0],
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end.dst4().Addr[1],
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end.dst4().Addr[2],
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end.dst4().Addr[3],
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)
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} else {
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return end.dst6().Addr[:]
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}
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}
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func (end *NativeEndpoint) DstToBytes() []byte {
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if !end.isV6 {
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return (*[unsafe.Offsetof(end.dst4().Addr) + unsafe.Sizeof(end.dst4().Addr)]byte)(unsafe.Pointer(end.dst4()))[:]
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} else {
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return (*[unsafe.Offsetof(end.dst6().Addr) + unsafe.Sizeof(end.dst6().Addr)]byte)(unsafe.Pointer(end.dst6()))[:]
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}
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}
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func (end *NativeEndpoint) SrcToString() string {
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return end.SrcIP().String()
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}
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func (end *NativeEndpoint) DstToString() string {
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var udpAddr net.UDPAddr
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udpAddr.IP = end.DstIP()
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if !end.isV6 {
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udpAddr.Port = end.dst4().Port
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} else {
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udpAddr.Port = end.dst6().Port
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}
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return udpAddr.String()
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}
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func (end *NativeEndpoint) ClearDst() {
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for i := range end.dst {
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end.dst[i] = 0
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}
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}
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func (end *NativeEndpoint) ClearSrc() {
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for i := range end.src {
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end.src[i] = 0
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}
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}
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func zoneToUint32(zone string) (uint32, error) {
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if zone == "" {
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return 0, nil
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}
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if intr, err := net.InterfaceByName(zone); err == nil {
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return uint32(intr.Index), nil
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}
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n, err := strconv.ParseUint(zone, 10, 32)
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return uint32(n), err
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}
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func create4(port uint16) (int, uint16, error) {
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// create socket
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fd, err := unix.Socket(
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unix.AF_INET,
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unix.SOCK_DGRAM,
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0,
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)
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if err != nil {
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return -1, 0, err
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}
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addr := unix.SockaddrInet4{
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Port: int(port),
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}
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// set sockopts and bind
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if err := func() error {
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if err := unix.SetsockoptInt(
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fd,
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unix.SOL_SOCKET,
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unix.SO_REUSEADDR,
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1,
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); err != nil {
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return err
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}
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if err := unix.SetsockoptInt(
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fd,
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unix.IPPROTO_IP,
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unix.IP_PKTINFO,
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1,
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); err != nil {
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return err
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}
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return unix.Bind(fd, &addr)
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}(); err != nil {
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unix.Close(fd)
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return -1, 0, err
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}
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return fd, uint16(addr.Port), err
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}
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func create6(port uint16) (int, uint16, error) {
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// create socket
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fd, err := unix.Socket(
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unix.AF_INET6,
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unix.SOCK_DGRAM,
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0,
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)
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if err != nil {
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return -1, 0, err
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}
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// set sockopts and bind
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addr := unix.SockaddrInet6{
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Port: int(port),
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}
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if err := func() error {
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if err := unix.SetsockoptInt(
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fd,
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unix.SOL_SOCKET,
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unix.SO_REUSEADDR,
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1,
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); err != nil {
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return err
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}
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if err := unix.SetsockoptInt(
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fd,
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unix.IPPROTO_IPV6,
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unix.IPV6_RECVPKTINFO,
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1,
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); err != nil {
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return err
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}
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if err := unix.SetsockoptInt(
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fd,
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unix.IPPROTO_IPV6,
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unix.IPV6_V6ONLY,
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1,
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); err != nil {
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return err
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}
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return unix.Bind(fd, &addr)
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}(); err != nil {
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unix.Close(fd)
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return -1, 0, err
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}
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return fd, uint16(addr.Port), err
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}
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func send4(sock int, end *NativeEndpoint, buff []byte) error {
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// construct message header
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cmsg := struct {
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cmsghdr unix.Cmsghdr
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pktinfo unix.Inet4Pktinfo
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}{
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unix.Cmsghdr{
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Level: unix.IPPROTO_IP,
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Type: unix.IP_PKTINFO,
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Len: unix.SizeofInet4Pktinfo + unix.SizeofCmsghdr,
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},
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unix.Inet4Pktinfo{
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Spec_dst: end.src4().src,
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Ifindex: end.src4().ifindex,
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},
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}
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_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
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if err == nil {
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return nil
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}
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// clear src and retry
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if err == unix.EINVAL {
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end.ClearSrc()
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cmsg.pktinfo = unix.Inet4Pktinfo{}
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_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
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}
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return err
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}
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func send6(sock int, end *NativeEndpoint, buff []byte) error {
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// construct message header
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cmsg := struct {
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cmsghdr unix.Cmsghdr
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pktinfo unix.Inet6Pktinfo
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}{
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unix.Cmsghdr{
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Level: unix.IPPROTO_IPV6,
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Type: unix.IPV6_PKTINFO,
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Len: unix.SizeofInet6Pktinfo + unix.SizeofCmsghdr,
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},
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unix.Inet6Pktinfo{
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Addr: end.src6().src,
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Ifindex: end.dst6().ZoneId,
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},
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}
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if cmsg.pktinfo.Addr == [16]byte{} {
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cmsg.pktinfo.Ifindex = 0
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}
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_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
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if err == nil {
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return nil
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}
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// clear src and retry
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if err == unix.EINVAL {
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end.ClearSrc()
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cmsg.pktinfo = unix.Inet6Pktinfo{}
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_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
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}
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return err
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}
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func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
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// contruct message header
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var cmsg struct {
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cmsghdr unix.Cmsghdr
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pktinfo unix.Inet4Pktinfo
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}
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size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
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if err != nil {
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return 0, err
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}
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end.isV6 = false
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if newDst4, ok := newDst.(*unix.SockaddrInet4); ok {
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*end.dst4() = *newDst4
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}
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// update source cache
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if cmsg.cmsghdr.Level == unix.IPPROTO_IP &&
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cmsg.cmsghdr.Type == unix.IP_PKTINFO &&
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cmsg.cmsghdr.Len >= unix.SizeofInet4Pktinfo {
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end.src4().src = cmsg.pktinfo.Spec_dst
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end.src4().ifindex = cmsg.pktinfo.Ifindex
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}
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return size, nil
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}
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func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
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// contruct message header
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var cmsg struct {
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cmsghdr unix.Cmsghdr
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pktinfo unix.Inet6Pktinfo
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}
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size, _, _, newDst, err := unix.Recvmsg(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], 0)
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if err != nil {
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return 0, err
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}
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end.isV6 = true
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if newDst6, ok := newDst.(*unix.SockaddrInet6); ok {
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*end.dst6() = *newDst6
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}
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// update source cache
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if cmsg.cmsghdr.Level == unix.IPPROTO_IPV6 &&
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cmsg.cmsghdr.Type == unix.IPV6_PKTINFO &&
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cmsg.cmsghdr.Len >= unix.SizeofInet6Pktinfo {
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end.src6().src = cmsg.pktinfo.Addr
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end.dst6().ZoneId = cmsg.pktinfo.Ifindex
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}
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return size, nil
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}
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|
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func (bind *NativeBind) routineRouteListener() {
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// TODO: this function doesn't lock the endpoint it modifies
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|
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for msg := make([]byte, 1<<16); ; {
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msgn, _, _, _, err := unix.Recvmsg(bind.netlinkSock, msg[:], nil, 0)
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if err != nil {
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return
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}
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for remain := msg[:msgn]; len(remain) >= unix.SizeofNlMsghdr; {
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hdr := *(*unix.NlMsghdr)(unsafe.Pointer(&remain[0]))
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if uint(hdr.Len) > uint(len(remain)) {
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break
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}
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switch hdr.Type {
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case unix.RTM_NEWROUTE, unix.RTM_DELROUTE:
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if bind.lastEndpoint == nil || bind.lastEndpoint.isV6 || bind.lastEndpoint.src4().ifindex == 0 {
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break
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}
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|
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if hdr.Seq == 0xff {
|
|
if uint(len(remain)) < uint(hdr.Len) {
|
|
break
|
|
}
|
|
if hdr.Len > unix.SizeofNlMsghdr+unix.SizeofRtMsg {
|
|
attr := remain[unix.SizeofNlMsghdr+unix.SizeofRtMsg:]
|
|
for {
|
|
if uint(len(attr)) < uint(unix.SizeofRtAttr) {
|
|
break
|
|
}
|
|
attrhdr := *(*unix.RtAttr)(unsafe.Pointer(&attr[0]))
|
|
if attrhdr.Len < unix.SizeofRtAttr || uint(len(attr)) < uint(attrhdr.Len) {
|
|
break
|
|
}
|
|
if attrhdr.Type == unix.RTA_OIF && attrhdr.Len == unix.SizeofRtAttr+4 {
|
|
ifidx := *(*uint32)(unsafe.Pointer(&attr[unix.SizeofRtAttr]))
|
|
if uint32(bind.lastEndpoint.src4().ifindex) != ifidx {
|
|
bind.lastEndpoint.ClearSrc()
|
|
}
|
|
}
|
|
attr = attr[attrhdr.Len:]
|
|
}
|
|
}
|
|
break
|
|
}
|
|
|
|
nlmsg := struct {
|
|
hdr unix.NlMsghdr
|
|
msg unix.RtMsg
|
|
dsthdr unix.RtAttr
|
|
dst [4]byte
|
|
srchdr unix.RtAttr
|
|
src [4]byte
|
|
markhdr unix.RtAttr
|
|
mark uint32
|
|
}{
|
|
unix.NlMsghdr{
|
|
Type: uint16(unix.RTM_GETROUTE),
|
|
Flags: unix.NLM_F_REQUEST,
|
|
Seq: 0xff,
|
|
},
|
|
unix.RtMsg{
|
|
Family: unix.AF_INET,
|
|
Dst_len: 32,
|
|
Src_len: 32,
|
|
},
|
|
unix.RtAttr{
|
|
Len: 8,
|
|
Type: unix.RTA_DST,
|
|
},
|
|
bind.lastEndpoint.dst4().Addr,
|
|
unix.RtAttr{
|
|
Len: 8,
|
|
Type: unix.RTA_SRC,
|
|
},
|
|
bind.lastEndpoint.src4().src,
|
|
unix.RtAttr{
|
|
Len: 8,
|
|
Type: 0x10, //unix.RTA_MARK TODO: add this to x/sys/unix
|
|
},
|
|
uint32(bind.lastMark),
|
|
}
|
|
nlmsg.hdr.Len = uint32(unsafe.Sizeof(nlmsg))
|
|
unix.Write(bind.netlinkSock, (*[unsafe.Sizeof(nlmsg)]byte)(unsafe.Pointer(&nlmsg))[:])
|
|
}
|
|
remain = remain[hdr.Len:]
|
|
}
|
|
}
|
|
}
|