102 lines
2.0 KiB
Go
102 lines
2.0 KiB
Go
package gost
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import (
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"errors"
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"fmt"
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"github.com/golang/glog"
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"net"
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"syscall"
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)
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const (
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SO_ORIGINAL_DST = 80
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)
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type RedsocksTCPServer struct {
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Base *ProxyServer
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}
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func NewRedsocksTCPServer(base *ProxyServer) *RedsocksTCPServer {
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return &RedsocksTCPServer{
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Base: base,
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}
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}
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func (s *RedsocksTCPServer) ListenAndServe() error {
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laddr, err := net.ResolveTCPAddr("tcp", s.Base.Node.Addr)
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if err != nil {
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return err
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}
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ln, err := net.ListenTCP("tcp", laddr)
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if err != nil {
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return err
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}
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defer ln.Close()
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for {
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conn, err := ln.AcceptTCP()
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if err != nil {
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glog.V(LWARNING).Infoln(err)
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continue
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}
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go s.handleRedirectTCP(conn)
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}
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}
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func (s *RedsocksTCPServer) handleRedirectTCP(conn *net.TCPConn) {
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srcAddr := conn.RemoteAddr()
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dstAddr, conn, err := getOriginalDstAddr(conn)
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if err != nil {
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glog.V(LWARNING).Infof("[red-tcp] %s -> %s : %s", srcAddr, dstAddr, err)
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return
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}
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defer conn.Close()
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glog.V(LINFO).Infof("[red-tcp] %s -> %s", srcAddr, dstAddr)
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cc, err := s.Base.Chain.Dial(dstAddr.String())
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if err != nil {
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glog.V(LWARNING).Infof("[red-tcp] %s -> %s : %s", srcAddr, dstAddr, err)
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return
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}
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defer cc.Close()
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glog.V(LINFO).Infof("[red-tcp] %s <-> %s", srcAddr, dstAddr)
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s.Base.transport(conn, cc)
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glog.V(LINFO).Infof("[red-tcp] %s >-< %s", srcAddr, dstAddr)
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}
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func getOriginalDstAddr(conn *net.TCPConn) (addr net.Addr, c *net.TCPConn, err error) {
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defer conn.Close()
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fc, err := conn.File()
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if err != nil {
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return
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}
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defer fc.Close()
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mreq, err := syscall.GetsockoptIPv6Mreq(int(fc.Fd()), syscall.IPPROTO_IP, SO_ORIGINAL_DST)
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if err != nil {
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return
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}
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// only ipv4 support
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ip := net.IPv4(mreq.Multiaddr[4], mreq.Multiaddr[5], mreq.Multiaddr[6], mreq.Multiaddr[7])
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port := uint16(mreq.Multiaddr[2])<<8 + uint16(mreq.Multiaddr[3])
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addr, err = net.ResolveTCPAddr("tcp4", fmt.Sprintf("%s:%d", ip.String(), port))
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if err != nil {
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return
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}
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cc, err := net.FileConn(fc)
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if err != nil {
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return
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}
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c, ok := cc.(*net.TCPConn)
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if !ok {
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err = errors.New("not a TCP connection")
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}
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return
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}
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