all: improve the method of import for internal packages

1. Change directory structure and Makefile to let GOPATH=`pwd`, so wherever the project directory is, just use make to build.

src/frp/models/client/client.go

@@ -0,0 +1,71 @@
+package client
+
+import (
+	"encoding/json"
+
+	"frp/models/consts"
+	"frp/models/msg"
+	"frp/utils/conn"
+	"frp/utils/log"
+)
+
+type ProxyClient struct {
+	Name      string
+	Passwd    string
+	LocalPort int64
+}
+
+func (p *ProxyClient) GetLocalConn() (c *conn.Conn, err error) {
+	c, err = conn.ConnectServer("127.0.0.1", p.LocalPort)
+	if err != nil {
+		log.Error("ProxyName [%s], connect to local port error, %v", p.Name, err)
+	}
+	return
+}
+
+func (p *ProxyClient) GetRemoteConn(addr string, port int64) (c *conn.Conn, err error) {
+	defer func() {
+		if err != nil {
+			c.Close()
+		}
+	}()
+
+	c, err = conn.ConnectServer(addr, port)
+	if err != nil {
+		log.Error("ProxyName [%s], connect to server [%s:%d] error, %v", p.Name, addr, port, err)
+		return
+	}
+
+	req := &msg.ClientCtlReq{
+		Type:      consts.WorkConn,
+		ProxyName: p.Name,
+		Passwd:    p.Passwd,
+	}
+
+	buf, _ := json.Marshal(req)
+	err = c.Write(string(buf) + "\n")
+	if err != nil {
+		log.Error("ProxyName [%s], write to server error, %v", p.Name, err)
+		return
+	}
+
+	err = nil
+	return
+}
+
+func (p *ProxyClient) StartTunnel(serverAddr string, serverPort int64) (err error) {
+	localConn, err := p.GetLocalConn()
+	if err != nil {
+		return
+	}
+	remoteConn, err := p.GetRemoteConn(serverAddr, serverPort)
+	if err != nil {
+		return
+	}
+
+	// l means local, r means remote
+	log.Debug("Join two conns, (l[%s] r[%s]) (l[%s] r[%s])", localConn.GetLocalAddr(), localConn.GetRemoteAddr(),
+		remoteConn.GetLocalAddr(), remoteConn.GetRemoteAddr())
+	go conn.Join(localConn, remoteConn)
+	return nil
+}