Begin work on source address caching (linux)
This commit is contained in:
Mathias Hall-Andersen
parent
c545d63bb9
commit
eefa47b0f9
22
src/conn.go
22
src/conn.go
@ -1,9 +1,31 @@
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package main
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import (
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"errors"
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"net"
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)
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func parseEndpoint(s string) (*net.UDPAddr, error) {
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// ensure that the host is an IP address
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host, _, err := net.SplitHostPort(s)
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if err != nil {
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return nil, err
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}
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if ip := net.ParseIP(host); ip == nil {
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return nil, errors.New("Failed to parse IP address: " + host)
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}
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// parse address and port
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addr, err := net.ResolveUDPAddr("udp", s)
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if err != nil {
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return nil, err
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}
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return addr, err
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}
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func updateUDPConn(device *Device) error {
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netc := &device.net
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netc.mutex.Lock()
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@ -1,10 +1,253 @@
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/* Copyright 2017 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.
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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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/* Supports source address caching
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*
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* It is important that the endpoint is only updated after the packet content has been authenticated.
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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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*/
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type Endpoint struct {
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// source (selected based on dst type)
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// (could use RawSockaddrAny and unsafe)
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srcIPv6 unix.RawSockaddrInet6
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srcIPv4 unix.RawSockaddrInet4
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srcIf4 int32
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dst unix.RawSockaddrAny
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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 (end *Endpoint) ClearSrc() {
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end.srcIf4 = 0
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end.srcIPv4 = unix.RawSockaddrInet4{}
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end.srcIPv6 = unix.RawSockaddrInet6{}
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}
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func (end *Endpoint) Set(s string) error {
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addr, err := parseEndpoint(s)
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if err != nil {
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return err
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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 err
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}
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ptr := (*unix.RawSockaddrInet6)(unsafe.Pointer(&end.dst))
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ptr.Family = unix.AF_INET6
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ptr.Port = uint16(addr.Port)
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ptr.Flowinfo = 0
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ptr.Scope_id = zone
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copy(ptr.Addr[:], ipv6[:])
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end.ClearSrc()
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return nil
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}
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ipv4 := addr.IP.To4()
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if ipv4 != nil {
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ptr := (*unix.RawSockaddrInet4)(unsafe.Pointer(&end.dst))
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ptr.Family = unix.AF_INET
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ptr.Port = uint16(addr.Port)
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ptr.Zero = [8]byte{}
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copy(ptr.Addr[:], ipv4)
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end.ClearSrc()
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return nil
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}
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return errors.New("Failed to recognize IP address format")
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}
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func send6(sock uintptr, end *Endpoint, buff []byte) error {
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var iovec unix.Iovec
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iovec.Base = (*byte)(unsafe.Pointer(&buff[0]))
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iovec.SetLen(len(buff))
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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,
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},
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unix.Inet6Pktinfo{
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Addr: end.srcIPv6.Addr,
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Ifindex: end.srcIPv6.Scope_id,
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},
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}
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msghdr := unix.Msghdr{
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Iov: &iovec,
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Iovlen: 1,
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Name: (*byte)(unsafe.Pointer(&end.dst)),
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Namelen: unix.SizeofSockaddrInet6,
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Control: (*byte)(unsafe.Pointer(&cmsg)),
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}
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msghdr.SetControllen(int(unsafe.Sizeof(cmsg)))
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// sendmsg(sock, &msghdr, 0)
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_, _, errno := unix.Syscall(
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unix.SYS_SENDMSG,
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sock,
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uintptr(unsafe.Pointer(&msghdr)),
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0,
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)
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if errno == unix.EINVAL {
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end.ClearSrc()
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}
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return errno
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}
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func send4(sock uintptr, end *Endpoint, buff []byte) error {
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var iovec unix.Iovec
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iovec.Base = (*byte)(unsafe.Pointer(&buff[0]))
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iovec.SetLen(len(buff))
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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.SizeofInet6Pktinfo,
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},
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unix.Inet4Pktinfo{
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Spec_dst: end.srcIPv4.Addr,
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Ifindex: end.srcIf4,
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},
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}
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msghdr := unix.Msghdr{
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Iov: &iovec,
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Iovlen: 1,
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Name: (*byte)(unsafe.Pointer(&end.dst)),
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Namelen: unix.SizeofSockaddrInet4,
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Control: (*byte)(unsafe.Pointer(&cmsg)),
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}
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msghdr.SetControllen(int(unsafe.Sizeof(cmsg)))
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// sendmsg(sock, &msghdr, 0)
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_, _, errno := unix.Syscall(
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unix.SYS_SENDMSG,
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sock,
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uintptr(unsafe.Pointer(&msghdr)),
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0,
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)
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if errno == unix.EINVAL {
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end.ClearSrc()
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}
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return errno
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}
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func send(c *net.UDPConn, end *Endpoint, buff []byte) error {
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// extract underlying file descriptor
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file, err := c.File()
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if err != nil {
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return err
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}
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sock := file.Fd()
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// send depending on address family of dst
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family := *((*uint16)(unsafe.Pointer(&end.dst)))
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if family == unix.AF_INET {
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return send4(sock, end, buff)
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} else if family == unix.AF_INET6 {
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return send6(sock, end, buff)
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}
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return errors.New("Unknown address family of source")
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}
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func receiveIPv4(end *Endpoint, c *net.UDPConn, buff []byte) (error, *net.UDPAddr, *net.UDPAddr) {
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file, err := c.File()
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if err != nil {
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return err, nil, nil
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}
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var iovec unix.Iovec
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iovec.Base = (*byte)(unsafe.Pointer(&buff[0]))
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iovec.SetLen(len(buff))
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var cmsg struct {
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cmsghdr unix.Cmsghdr
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pktinfo unix.Inet6Pktinfo // big enough
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}
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var msg unix.Msghdr
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msg.Iov = &iovec
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msg.Iovlen = 1
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msg.Name = (*byte)(unsafe.Pointer(&end.dst))
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msg.Namelen = uint32(unix.SizeofSockaddrAny)
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msg.Control = (*byte)(unsafe.Pointer(&cmsg))
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msg.SetControllen(int(unsafe.Sizeof(cmsg)))
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_, _, errno := unix.Syscall(
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unix.SYS_RECVMSG,
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file.Fd(),
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uintptr(unsafe.Pointer(&msg)),
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0,
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)
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if errno != 0 {
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return errno, nil, nil
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}
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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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}
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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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info := (*unix.Inet4Pktinfo)(unsafe.Pointer(&cmsg.pktinfo))
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println(info)
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}
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return nil, nil, nil
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}
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func setMark(conn *net.UDPConn, value uint32) error {
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if conn == nil {
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return nil
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@ -29,6 +29,11 @@ func (a *AtomicBool) Set(val bool) {
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atomic.StoreInt32(&a.flag, flag)
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}
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func toInt32(n uint32) int32 {
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mask := uint32(1 << 31)
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return int32(-(n & mask) + (n & ^mask))
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}
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func min(a uint, b uint) uint {
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if a > b {
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return b
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@ -120,14 +120,6 @@ func (tun *NativeTun) Name() string {
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return tun.name
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}
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func toInt32(val []byte) int32 {
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n := binary.LittleEndian.Uint32(val[:4])
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if n >= (1 << 31) {
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return -int32(^n) - 1
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}
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return int32(n)
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}
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func getDummySock() (int, error) {
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return unix.Socket(
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unix.AF_INET,
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@ -157,7 +149,8 @@ func getIFIndex(name string) (int32, error) {
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return 0, errno
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}
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return toInt32(ifr[unix.IFNAMSIZ:]), nil
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index := binary.LittleEndian.Uint32(ifr[unix.IFNAMSIZ:])
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return toInt32(index), nil
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}
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func (tun *NativeTun) setMTU(n int) error {
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@ -273,8 +273,7 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
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}
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case "endpoint":
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// TODO: Only IP and port
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addr, err := net.ResolveUDPAddr("udp", value)
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addr, err := parseEndpoint(value)
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if err != nil {
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logError.Println("Failed to set endpoint:", value)
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return &IPCError{Code: ipcErrorInvalid}
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