fix udp port forwarding

README.md

@@ -11,6 +11,7 @@ gost - GO Simple Tunnel
 * socks5代理支持tls协商加密
 * Tunnel UDP over TCP
 * 兼容shadowsocks协议
+* 支持端口转发(2.1及以上版本)
 
 二进制文件下载：https://github.com/ginuerzh/gost/releases
 
@@ -20,13 +21,16 @@ Google讨论组: https://groups.google.com/d/forum/go-gost
 
 参数说明
 ------
-#### -L和-F参数格式
+#### 代理及转发链
+
+适用于-L和-F参数
+
 ```bash
 [scheme://][user:pass@host]:port
 ```
 scheme分为两部分: protocol+transport
 
-protocol: 代理协议类型(http, socks5, shadowsocks), transport: 数据传输方式(tcp, ws, wss, tls), 二者可以任意组合，或单独使用。
+protocol: 代理协议类型(http, socks5, shadowsocks), transport: 数据传输方式(ws, wss, tls), 二者可以任意组合，或单独使用:
 
 > http - 作为http代理: http://:8080
 
@@ -40,6 +44,21 @@ protocol: 代理协议类型(http, socks5, shadowsocks), transport: 数据传输
 
 > ss - 作为shadowsocks服务，ss://aes-256-cfb:123456@:8080
 
+#### 本地端口转发
+
+适用于-L参数
+
+```bash
+scheme://[bind_address]:port/[host]:hostport
+```	
+> scheme - 端口转发类型: tcp, udp
+
+> bind_address:port - 本地监听地址
+
+> host:hostport - 远程监听地址
+
+当在bind_address:port上收到连接信息，则会(通过转发链)与host:hostport建立连接，创建一条数据通道。
+
 #### 开启日志
 
 > -logtostderr : 输出到控制台
@@ -90,6 +109,22 @@ gost -L=:8080 -F=http+tls://192.168.1.1:443 -F=socks+ws://192.168.1.2:1080 -F=ss
 ```
 gost按照-F设置顺序通过转发链将请求最终转发给a.b.c.d:NNNN处理，每一个转发代理可以是任意http(s)/socks5/shadowsocks类型代理。
 
+#### 本地端口转发(TCP)
+
+```bash
+gost -L=tcp://:2222/192.168.1.1:22 -F=...
+```
+将本地TCP端口2222上的数据(通过转发链)转发到192.168.1.1:22上。
+
+#### 本地端口转发(UDP)
+
+```bash
+gost -L=udp://:5353/192.168.1.1:53 -F=...
+```
+将本地UDP端口5353上的数据(通过转发链)转发到192.168.1.1:53上。
+
+**注: 如果有转发链，则转发链的末端(最后一个-F参数)必须是gost socks5类型代理。**
+
 加密机制
 ------
 #### HTTP

forward.go

@@ -5,11 +5,15 @@ import (
 	"github.com/golang/glog"
 	"net"
 	"strings"
+	"time"
 )
 
 func handleTcpForward(conn net.Conn, arg Args) {
 	defer conn.Close()
-	glog.V(LINFO).Infof("[tcp-forward] %s -> %s", conn.RemoteAddr(), arg.Forward)
+	if !strings.Contains(arg.Forward, ":") {
+		arg.Forward += ":22" // default is ssh service
+	}
+	glog.V(LINFO).Infof("[tcp-forward] %s - %s", conn.RemoteAddr(), arg.Forward)
 	c, err := Connect(arg.Forward)
 	if err != nil {
 		glog.V(LWARNING).Infof("[tcp-forward] %s -> %s : %s", conn.RemoteAddr(), arg.Forward, err)
@@ -24,9 +28,48 @@ func handleTcpForward(conn net.Conn, arg Args) {
 
 func handleUdpForward(conn *net.UDPConn, raddr *net.UDPAddr, data []byte, arg Args) {
 	if !strings.Contains(arg.Forward, ":") {
-		arg.Forward += ":53"
+		arg.Forward += ":53" // default is dns service
+	}
+
+	faddr, err := net.ResolveUDPAddr("udp", arg.Forward)
+	if err != nil {
+		glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
+		return
 	}
-	glog.V(LINFO).Infof("[udp-forward] %s -> %s", raddr, arg.Forward)
+
+	glog.V(LINFO).Infof("[udp-forward] %s - %s", raddr, faddr)
+
+	if len(forwardArgs) == 0 {
+		lconn, err := net.ListenUDP("udp", nil)
+		if err != nil {
+			glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
+			return
+		}
+		defer lconn.Close()
+
+		if _, err := lconn.WriteToUDP(data, faddr); err != nil {
+			glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
+			return
+		}
+		glog.V(LINFO).Infof("[udp-forward] %s >>> %s length %d", raddr, arg.Forward, len(data))
+
+		b := udpPool.Get().([]byte)
+		defer udpPool.Put(b)
+		lconn.SetReadDeadline(time.Now().Add(time.Second * 60))
+		n, addr, err := lconn.ReadFromUDP(b)
+		if err != nil {
+			glog.V(LWARNING).Infof("[udp-forward] %s <- %s : %s", raddr, arg.Forward, err)
+			return
+		}
+		glog.V(LINFO).Infof("[udp-forward] %s <<< %s length %d", raddr, addr, n)
+
+		if _, err := conn.WriteToUDP(b[:n], raddr); err != nil {
+			glog.V(LWARNING).Infof("[udp-forward] %s <- %s : %s", raddr, arg.Forward, err)
+		}
+		glog.V(LINFO).Infof("[udp-forward] %s >-< %s DONE", raddr, arg.Forward)
+		return
+	}
+
 	fconn, _, err := forwardChain(forwardArgs...)
 	if err != nil {
 		glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
@@ -58,27 +101,27 @@ func handleUdpForward(conn *net.UDPConn, raddr *net.UDPAddr, data []byte, arg Ar
 	}
 	glog.V(LINFO).Infof("[udp-forward] %s <-> %s ASSOCIATE ON %s OK", raddr, arg.Forward, rep.Addr)
 
-	addr, err := net.ResolveUDPAddr("udp", arg.Forward)
-	if err != nil {
-		glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
-		return
-	}
 	dgram := gosocks5.NewUDPDatagram(
-		gosocks5.NewUDPHeader(uint16(len(data)), 0, ToSocksAddr(addr)), data)
+		gosocks5.NewUDPHeader(uint16(len(data)), 0, ToSocksAddr(faddr)), data)
+
+	fconn.SetWriteDeadline(time.Now().Add(time.Second * 60))
 	if err = dgram.Write(fconn); err != nil {
 		glog.V(LWARNING).Infof("[udp-forward] %s -> %s : %s", raddr, arg.Forward, err)
 		return
 	}
 	glog.V(LINFO).Infof("[udp-forward] %s >>> %s length %d", raddr, arg.Forward, len(data))
 
+	fconn.SetReadDeadline(time.Now().Add(time.Second * 60))
 	dgram, err = gosocks5.ReadUDPDatagram(fconn)
 	if err != nil {
 		glog.V(LWARNING).Infof("[udp-forward] %s <- %s : %s", raddr, arg.Forward, err)
 		return
 	}
-	glog.V(LINFO).Infof("[udp-forward] %s <<< %s length %d", raddr, arg.Forward, len(dgram.Data))
+	glog.V(LINFO).Infof("[udp-forward] %s <<< %s length %d", raddr, dgram.Header.Addr, len(dgram.Data))
 
 	if _, err = conn.WriteToUDP(dgram.Data, raddr); err != nil {
 		glog.V(LWARNING).Infof("[udp-forward] %s <- %s : %s", raddr, arg.Forward, err)
 	}
+
+	glog.V(LINFO).Infof("[udp-forward] %s >-< %s DONE", raddr, arg.Forward)
 }

http.go

@@ -18,7 +18,7 @@ func handleHttpRequest(req *http.Request, conn net.Conn, arg Args) {
 			glog.Infoln(string(dump))
 		}
 	}
-	glog.V(LINFO).Infof("[http] %s -> %s", conn.RemoteAddr(), req.Host)
+	glog.V(LINFO).Infof("[http] %s - %s", conn.RemoteAddr(), req.Host)
 
 	var username, password string
 	if arg.User != nil {

socks.go

@@ -166,7 +166,7 @@ func handleSocks5Request(req *gosocks5.Request, conn net.Conn) {
 
 	switch req.Cmd {
 	case gosocks5.CmdConnect:
-		glog.V(LINFO).Infof("[socks5-connect] %s -> %s", conn.RemoteAddr(), req.Addr)
+		glog.V(LINFO).Infof("[socks5-connect] %s - %s", conn.RemoteAddr(), req.Addr)
 
 		tconn, err := Connect(req.Addr.String())
 		if err != nil {
@@ -192,7 +192,7 @@ func handleSocks5Request(req *gosocks5.Request, conn net.Conn) {
 		Transport(conn, tconn)
 		glog.V(LINFO).Infof("[socks5-connect] %s >-< %s DISCONNECTED", conn.RemoteAddr(), req.Addr)
 	case gosocks5.CmdBind:
-		glog.V(LINFO).Infof("[socks5-bind] %s -> %s", conn.RemoteAddr(), req.Addr)
+		glog.V(LINFO).Infof("[socks5-bind] %s - %s", conn.RemoteAddr(), req.Addr)
 
 		if len(forwardArgs) > 0 {
 			forwardBind(req, conn)
@@ -202,7 +202,7 @@ func handleSocks5Request(req *gosocks5.Request, conn net.Conn) {
 		glog.V(LINFO).Infof("[socks5-bind] %s >-< %s DISCONNECTED", conn.RemoteAddr(), req.Addr)
 	case gosocks5.CmdUdp, CmdUdpTun:
 		// TODO: udp tunnel <-> forward chain
-		glog.V(LINFO).Infof("[socks5-udp] %s -> %s ASSOCIATE", conn.RemoteAddr(), req.Addr)
+		glog.V(LINFO).Infof("[socks5-udp] %s - %s ASSOCIATE", conn.RemoteAddr(), req.Addr)
 		uconn, err := net.ListenUDP("udp", nil)
 		if err != nil {
 			glog.V(LWARNING).Infof("[socks5-udp] %s -> %s : %s", conn.RemoteAddr(), req.Addr, err)