package v5 import ( "context" "net" "time" "github.com/go-gost/gosocks5" "github.com/go-gost/gost/pkg/chain" "github.com/go-gost/gost/pkg/handler" ) func (h *socks5Handler) handleBind(ctx context.Context, conn net.Conn, req *gosocks5.Request) { addr := req.Addr.String() h.logger = h.logger.WithFields(map[string]interface{}{ "dst": addr, "cmd": "bind", }) h.logger.Infof("%s >> %s", conn.RemoteAddr(), addr) if !h.md.enableBind { reply := gosocks5.NewReply(gosocks5.NotAllowed, nil) reply.Write(conn) h.logger.Debug(reply) h.logger.Error("BIND is diabled") return } if h.chain.IsEmpty() { h.bindLocal(ctx, conn, addr) return } r := (&chain.Router{}). WithChain(h.chain). WithRetry(h.md.retryCount). WithLogger(h.logger) cc, err := r.Connect(ctx) if err != nil { resp := gosocks5.NewReply(gosocks5.Failure, nil) resp.Write(conn) h.logger.Debug(resp) return } defer cc.Close() // forward request if err := req.Write(cc); err != nil { h.logger.Error(err) resp := gosocks5.NewReply(gosocks5.NetUnreachable, nil) resp.Write(conn) h.logger.Debug(resp) return } h.logger.Infof("%s <-> %s", conn.RemoteAddr(), addr) handler.Transport(conn, cc) h.logger.Infof("%s >-< %s", conn.RemoteAddr(), addr) } func (h *socks5Handler) bindLocal(ctx context.Context, conn net.Conn, addr string) { bindAddr, _ := net.ResolveTCPAddr("tcp", addr) ln, err := net.ListenTCP("tcp", bindAddr) // strict mode: if the port already in use, it will return error if err != nil { h.logger.Error(err) reply := gosocks5.NewReply(gosocks5.Failure, nil) if err := reply.Write(conn); err != nil { h.logger.Error(err) } h.logger.Debug(reply) return } socksAddr := gosocks5.Addr{} if err := socksAddr.ParseFrom(ln.Addr().String()); err != nil { h.logger.Warn(err) } // Issue: may not reachable when host has multi-interface socksAddr.Host, _, _ = net.SplitHostPort(conn.LocalAddr().String()) socksAddr.Type = 0 reply := gosocks5.NewReply(gosocks5.Succeeded, &socksAddr) if err := reply.Write(conn); err != nil { h.logger.Error(err) ln.Close() return } h.logger.Debug(reply) h.logger = h.logger.WithFields(map[string]interface{}{ "bind": socksAddr.String(), }) h.logger.Debugf("bind on %s OK", &socksAddr) h.serveBind(ctx, conn, ln) } func (h *socks5Handler) serveBind(ctx context.Context, conn net.Conn, ln net.Listener) { var rc net.Conn accept := func() <-chan error { errc := make(chan error, 1) go func() { defer close(errc) defer ln.Close() c, err := ln.Accept() if err != nil { errc <- err } rc = c }() return errc } pc1, pc2 := net.Pipe() pipe := func() <-chan error { errc := make(chan error, 1) go func() { defer close(errc) defer pc1.Close() errc <- handler.Transport(conn, pc1) }() return errc } defer pc2.Close() select { case err := <-accept(): if err != nil { h.logger.Error(err) reply := gosocks5.NewReply(gosocks5.Failure, nil) if err := reply.Write(pc2); err != nil { h.logger.Error(err) } h.logger.Debug(reply) return } defer rc.Close() h.logger.Debugf("peer %s accepted", rc.RemoteAddr()) raddr := gosocks5.Addr{} raddr.ParseFrom(rc.RemoteAddr().String()) reply := gosocks5.NewReply(gosocks5.Succeeded, &raddr) if err := reply.Write(pc2); err != nil { h.logger.Error(err) } h.logger.Debug(reply) start := time.Now() h.logger.Infof("%s <-> %s", conn.RemoteAddr(), raddr.String()) handler.Transport(pc2, rc) h.logger. WithFields(map[string]interface{}{"duration": time.Since(start)}). Infof("%s >-< %s", conn.RemoteAddr(), raddr.String()) case err := <-pipe(): if err != nil { h.logger.Error(err) } ln.Close() return } }