fix

client.go

@@ -111,6 +111,7 @@ func (p *Client) Run() {
 		select {
 		case <-interval.C:
 			p.checkTimeoutConn()
+			p.ping()
 		case r := <-recv:
 			p.processPacket(r)
 		}
@@ -199,3 +200,10 @@ func (p *Client) checkTimeoutConn() {
 		}
 	}
 }
+
+func (p *Client) ping() {
+	now := time.Now()
+	b, _ := now.MarshalBinary()
+	sendICMP(*p.conn, p.ipaddrServer, p.targetAddr, "", (uint32)(PING), b, p.sproto, p.rproto)
+	fmt.Printf("ping %s %s\n", p.addrServer, now.String())
+}

pingtunnel.go

@@ -17,6 +17,8 @@ import (
 
 const (
 	DATA uint32 = 0x01010101
+	PING uint32 = 0x02020202
+	END  uint32 = 0xAAAABBBB
 )
 
 // An Echo represents an ICMP echo request or reply message body.
@@ -131,7 +133,7 @@ func sendICMP(conn icmp.PacketConn, server *net.IPAddr, target string, connId st
 		TARGET:  target,
 		Data:    data,
 		RPROTO:  (uint16)(rproto),
-		ENDTYPE: msgType,
+		ENDTYPE: END,
 	}
 
 	msg := &icmp.Message{
@@ -184,26 +186,27 @@ func recvICMP(conn icmp.PacketConn, recv chan<- *Packet) {
 		}
 		my.Unmarshal(bytes[4:n])
 
-		if my.TYPE != (uint32)(DATA) || my.ENDTYPE != (uint32)(DATA) {
+		if (my.TYPE != (uint32)(DATA) && my.TYPE != (uint32)(PING)) || my.ENDTYPE != (uint32)(END) {
 			//fmt.Printf("processPacket diff type %s %d %d \n", my.ID, my.TYPE, my.ENDTYPE)
 			continue
 		}
 
 		if my.Data == nil {
-			//fmt.Printf("processPacket data nil %s\n", my.ID)
+			fmt.Printf("processPacket data nil %s\n", my.ID)
 			return
 		}
 
-		recv <- &Packet{data: my.Data, id: my.ID, target: my.TARGET, src: srcaddr.(*net.IPAddr), rproto: (int)(my.RPROTO)}
+		recv <- &Packet{msgType: my.TYPE, data: my.Data, id: my.ID, target: my.TARGET, src: srcaddr.(*net.IPAddr), rproto: (int)(my.RPROTO)}
 	}
 }
 
 type Packet struct {
-	data   []byte
-	id     string
-	target string
-	src    *net.IPAddr
-	rproto int
+	msgType uint32
+	data    []byte
+	id      string
+	target  string
+	src     *net.IPAddr
+	rproto  int
 }
 
 func UniqueId() string {

server.go

@@ -59,6 +59,12 @@ func (p *Server) Run() {
 
 func (p *Server) processPacket(packet *Packet) {
 
+	if packet.msgType == PING {
+		fmt.Printf("pong from %s\n", packet.src.String())
+		sendICMP(*p.conn, packet.src, "", "", (uint32)(DATA), packet.data, packet.rproto, 0)
+		return
+	}
+
 	fmt.Printf("processPacket %s %s %d\n", packet.id, packet.src.String(), len(packet.data))
 
 	now := time.Now()