mirror of
https://github.com/xjasonlyu/tun2socks.git
synced 2025-10-07 01:33:15 +08:00
107 lines
2.4 KiB
Go
107 lines
2.4 KiB
Go
package redirect
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import (
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"errors"
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"fmt"
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"net"
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"sync"
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"time"
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"github.com/xjasonlyu/tun2socks/common/log"
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"github.com/xjasonlyu/tun2socks/common/pool"
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"github.com/xjasonlyu/tun2socks/core"
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)
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type udpHandler struct {
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target string
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timeout time.Duration
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remoteAddrMap sync.Map
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remoteUDPConnMap sync.Map
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}
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func NewUDPHandler(target string, timeout time.Duration) core.UDPConnHandler {
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return &udpHandler{
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target: target,
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timeout: timeout,
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}
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}
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func (h *udpHandler) fetchUDPInput(conn core.UDPConn, pc *net.UDPConn) {
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buf := pool.BufPool.Get().([]byte)
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defer func() {
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h.Close(conn)
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pool.BufPool.Put(buf[:cap(buf)])
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}()
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for {
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pc.SetDeadline(time.Now().Add(h.timeout))
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n, addr, err := pc.ReadFromUDP(buf)
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if err != nil {
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if err, ok := err.(net.Error); !ok && !err.Timeout() {
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log.Warnf("failed to read UDP data from remote: %v", err)
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}
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return
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}
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if _, err := conn.WriteFrom(buf[:n], addr); err != nil {
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log.Warnf("failed to write UDP data to TUN")
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return
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}
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}
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}
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func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
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bindAddr := &net.UDPAddr{IP: nil, Port: 0}
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pc, err := net.ListenUDP("udp", bindAddr)
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if err != nil {
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log.Errorf("failed to bind udp address")
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return err
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}
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targetAddr, _ := net.ResolveUDPAddr("udp", h.target)
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h.remoteAddrMap.Store(conn, targetAddr)
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h.remoteUDPConnMap.Store(conn, pc)
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go h.fetchUDPInput(conn, pc)
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log.Infof("new proxy connection for target: %s:%s", target.Network(), target.String())
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return nil
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}
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func (h *udpHandler) ReceiveTo(conn core.UDPConn, data []byte, addr *net.UDPAddr) error {
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var pc *net.UDPConn
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var targetAddr *net.UDPAddr
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if value, ok := h.remoteAddrMap.Load(conn); ok {
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targetAddr = value.(*net.UDPAddr)
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}
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if value, ok := h.remoteUDPConnMap.Load(conn); ok {
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pc = value.(*net.UDPConn)
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}
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if pc != nil && targetAddr != nil {
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_, err := pc.WriteToUDP(data, targetAddr)
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if err != nil {
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log.Warnf("failed to write UDP payload to SOCKS5 server: %v", err)
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return errors.New("failed to write UDP data")
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}
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return nil
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} else {
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return errors.New(fmt.Sprintf("proxy connection %v->%v does not exists", conn.LocalAddr(), addr))
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}
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}
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func (h *udpHandler) Close(conn core.UDPConn) {
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conn.Close()
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if pc, ok := h.remoteUDPConnMap.Load(conn); ok {
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pc.(*net.UDPConn).Close()
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h.remoteUDPConnMap.Delete(conn)
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}
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h.remoteAddrMap.Delete(conn)
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}
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