From 93fa95f27a491cd2e836b2e75e25f30faa89ed36 Mon Sep 17 00:00:00 2001
From: "rui.zheng" <rui.zheng@tcl.com>
Date: Mon, 14 Aug 2017 22:13:11 +0800
Subject: [PATCH] add data forward support for tunnels

---
 cmd/gost/main.go | 15 ++++++++++++---
 forward.go       | 45 +++++++++++++++++++++++++++++++++++++++++++++
 node.go          |  5 ++---
 sni.go           |  2 +-
 4 files changed, 60 insertions(+), 7 deletions(-)

diff --git a/cmd/gost/main.go b/cmd/gost/main.go
index 1ee4221..1cba6e7 100644
--- a/cmd/gost/main.go
+++ b/cmd/gost/main.go
@@ -129,7 +129,7 @@ func initChain() (*gost.Chain, error) {
 			}
 			tr = gost.KCPTransporter(config)
 		case "ssh":
-			if node.Protocol == "direct" || node.Protocol == "remote" || node.Protocol == "forward" {
+			if node.Protocol == "direct" || node.Protocol == "remote" {
 				tr = gost.SSHForwardTransporter()
 			} else {
 				tr = gost.SSHTunnelTransporter()
@@ -187,10 +187,12 @@ func initChain() (*gost.Chain, error) {
 			connector = gost.SOCKS4AConnector()
 		case "ss":
 			connector = gost.ShadowConnector(node.User)
-		case "direct", "forward":
+		case "direct":
 			connector = gost.SSHDirectForwardConnector()
 		case "remote":
 			connector = gost.SSHRemoteForwardConnector()
+		case "forward":
+			connector = gost.ForwardConnector()
 		case "http":
 			fallthrough
 		default:
@@ -239,6 +241,7 @@ func serve(chain *gost.Chain) error {
 		if err != nil && certFile != "" && keyFile != "" {
 			return err
 		}
+
 		var ln gost.Listener
 		switch node.Transport {
 		case "tls":
@@ -364,8 +367,14 @@ func serve(chain *gost.Chain) error {
 		case "sni":
 			handler = gost.SNIHandler(handlerOptions...)
 		default:
-			handler = gost.AutoHandler(handlerOptions...)
+			// start from 2.5, if remote is not empty, then we assume that it is a forward tunnel
+			if node.Remote != "" {
+				handler = gost.ForwardHandler(node.Remote, handlerOptions...)
+			} else {
+				handler = gost.AutoHandler(handlerOptions...)
+			}
 		}
+
 		srv := &gost.Server{Listener: ln}
 		go srv.Serve(handler)
 	}
diff --git a/forward.go b/forward.go
index 5c5e9a6..b0f4bb0 100644
--- a/forward.go
+++ b/forward.go
@@ -12,6 +12,51 @@ import (
 	"github.com/go-log/log"
 )
 
+type forwardConnector struct {
+}
+
+// ForwardConnector creates a Connector for data forward client.
+func ForwardConnector() Connector {
+	return &forwardConnector{}
+}
+
+func (c *forwardConnector) Connect(conn net.Conn, addr string) (net.Conn, error) {
+	return conn, nil
+}
+
+type forwardHandler struct {
+	raddr   string
+	options *HandlerOptions
+}
+
+// ForwardHandler creates a server Handler for data forwarding server.
+func ForwardHandler(raddr string, opts ...HandlerOption) Handler {
+	h := &forwardHandler{
+		raddr:   raddr,
+		options: &HandlerOptions{},
+	}
+	for _, opt := range opts {
+		opt(h.options)
+	}
+	return h
+}
+
+func (h *forwardHandler) Handle(conn net.Conn) {
+	defer conn.Close()
+
+	log.Logf("[forward] %s - %s", conn.RemoteAddr(), h.raddr)
+	cc, err := h.options.Chain.Dial(h.raddr)
+	if err != nil {
+		log.Logf("[forward] %s -> %s : %s", conn.RemoteAddr(), h.raddr, err)
+		return
+	}
+	defer cc.Close()
+
+	log.Logf("[forward] %s <-> %s", conn.RemoteAddr(), h.raddr)
+	transport(conn, cc)
+	log.Logf("[forward] %s >-< %s", conn.RemoteAddr(), h.raddr)
+}
+
 type tcpDirectForwardHandler struct {
 	raddr   string
 	options *HandlerOptions
diff --git a/node.go b/node.go
index 8b1e943..629bec7 100644
--- a/node.go
+++ b/node.go
@@ -36,6 +36,7 @@ func ParseNode(s string) (node Node, err error) {
 
 	node = Node{
 		Addr:   u.Host,
+		Remote: strings.Trim(u.EscapedPath(), "/"),
 		Values: u.Query(),
 		User:   u.User,
 	}
@@ -56,9 +57,7 @@ func ParseNode(s string) (node Node, err error) {
 		node.Protocol = "http"
 		node.Transport = "tls"
 	case "tcp", "udp": // started from v2.1, tcp and udp are for local port forwarding
-		node.Remote = strings.Trim(u.EscapedPath(), "/")
 	case "rtcp", "rudp": // rtcp and rudp are for remote port forwarding
-		node.Remote = strings.Trim(u.EscapedPath(), "/")
 	default:
 		node.Transport = "tcp"
 	}
@@ -68,7 +67,7 @@ func ParseNode(s string) (node Node, err error) {
 	case "socks", "socks5":
 		node.Protocol = "socks5"
 	case "tcp", "udp", "rtcp", "rudp": // port forwarding
-	case "direct", "remote", "forward": // SSH port forwarding
+	case "direct", "remote", "forward": // forwarding
 	case "redirect": // TCP transparent proxy
 	default:
 		node.Protocol = ""
diff --git a/sni.go b/sni.go
index 3d984c0..cc06d55 100644
--- a/sni.go
+++ b/sni.go
@@ -56,7 +56,7 @@ func (h *sniHandler) Handle(conn net.Conn) {
 		return
 	}
 
-	cc, err := options.Chain.Dial(sni)
+	cc, err := options.Chain.Dial(sni + ":443")
 	if err != nil {
 		log.Logf("[sni] %s -> %s : %s", conn.RemoteAddr(), sni, err)
 		return