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Refactor(tunnel): udp packet relay

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xjasonlyu
2022-04-05 23:14:16 +08:00
parent ab728bd8cc
commit 102b46e9f6
1 changed files with 33 additions and 39 deletions
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72
tunnel/udp.go
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@@ -1,9 +1,8 @@
package tunnel
import (
"errors"
"net"
"os"
"sync"
"time"
"github.com/xjasonlyu/tun2socks/v2/common/pool"
@@ -55,53 +54,48 @@ func handleUDPConn(uc adapter.UDPConn) {
remote = metadata.Addr()
}
go handleUDPToRemote(uc, pc, remote)
handleUDPToLocal(uc, pc, remote)
log.Infof("[UDP] %s <-> %s", metadata.SourceAddress(), metadata.DestinationAddress())
relayPacket(uc, pc, remote)
}
func handleUDPToRemote(uc adapter.UDPConn, pc net.PacketConn, remote net.Addr) {
func relayPacket(left net.PacketConn, right net.PacketConn, to net.Addr) {
wg := sync.WaitGroup{}
wg.Add(2)
go func() {
defer wg.Done()
if err := copyPacketBuffer(right, left, to, _udpSessionTimeout); err != nil {
log.Warnf("[UDP] copy packet buffer: %v", err)
}
}()
go func() {
defer wg.Done()
if err := copyPacketBuffer(left, right, nil, _udpSessionTimeout); err != nil {
log.Warnf("[UDP] copy packet buffer: %v", err)
}
}()
wg.Wait()
}
func copyPacketBuffer(dst net.PacketConn, src net.PacketConn, to net.Addr, timeout time.Duration) error {
buf := pool.Get(pool.MaxSegmentSize)
defer pool.Put(buf)
for {
n, err := uc.Read(buf)
src.SetReadDeadline(time.Now().Add(timeout))
n, _, err := src.ReadFrom(buf)
if err != nil {
return
}
if _, err := pc.WriteTo(buf[:n], remote); err != nil {
log.Warnf("[UDP] write to %s: %v", remote, err)
}
pc.SetReadDeadline(time.Now().Add(_udpSessionTimeout)) /* reset timeout */
log.Infof("[UDP] %s --> %s", uc.RemoteAddr(), remote)
}
}
func handleUDPToLocal(uc adapter.UDPConn, pc net.PacketConn, remote net.Addr) {
buf := pool.Get(pool.MaxSegmentSize)
defer pool.Put(buf)
for {
pc.SetReadDeadline(time.Now().Add(_udpSessionTimeout))
n, from, err := pc.ReadFrom(buf)
if err != nil {
if !errors.Is(err, os.ErrDeadlineExceeded) /* ignore I/O timeout */ {
log.Warnf("[UDP] read from %s: %v", pc.LocalAddr(), err)
if ne, ok := err.(net.Error); ok && ne.Timeout() {
return nil /* ignore I/O timeout */
}
return
return err
}
if from == nil || from.Network() != remote.Network() || from.String() != remote.String() {
log.Warnf("[UDP] drop unknown packet from %v", from)
return
if _, err = dst.WriteTo(buf[:n], to); err != nil {
return err
}
if _, err := uc.Write(buf[:n]); err != nil {
log.Warnf("[UDP] write back from %s: %v", from, err)
return
}
log.Infof("[UDP] %s <-- %s", uc.RemoteAddr(), from)
dst.SetReadDeadline(time.Now().Add(timeout))
}
}