From 75edf4c3c143a6f9203aac71744ba61517a3d7cb Mon Sep 17 00:00:00 2001
From: esrrhs <esrrhs@163.com>
Date: Fri, 21 Dec 2018 15:52:34 +0800
Subject: [PATCH] add

---
 client.go     | 12 ++++++++++--
 pingtunnel.go | 14 +++++++++++---
 server.go     | 12 ++++++++++--
 3 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/client.go b/client.go
index f8f0629..3cadb31 100644
--- a/client.go
+++ b/client.go
@@ -3,6 +3,8 @@ package pingtunnel
 import (
 	"fmt"
 	"golang.org/x/net/icmp"
+	"math"
+	"math/rand"
 	"net"
 	"time"
 )
@@ -19,7 +21,10 @@ func NewClient(addr string, server string, target string, timeout int, sproto in
 		return nil, err
 	}
 
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 	return &Client{
+		id:           r.Intn(math.MaxInt16),
+		r:            r,
 		ipaddr:       ipaddr,
 		addr:         addr,
 		ipaddrServer: ipaddrServer,
@@ -32,6 +37,9 @@ func NewClient(addr string, server string, target string, timeout int, sproto in
 }
 
 type Client struct {
+	id int
+	r  *rand.Rand
+
 	timeout int
 	sproto  int
 	rproto  int
@@ -156,7 +164,7 @@ func (p *Client) Accept() error {
 		}
 
 		clientConn.activeTime = now
-		sendICMP(*p.conn, p.ipaddrServer, p.targetAddr, clientConn.id, (uint32)(DATA), bytes[:n], p.sproto, p.rproto)
+		sendICMP(p.id, p.r.Intn(math.MaxInt16), *p.conn, p.ipaddrServer, p.targetAddr, clientConn.id, (uint32)(DATA), bytes[:n], p.sproto, p.rproto)
 
 		p.sendPacket++
 		p.sendPacketSize += (uint64)(n)
@@ -229,7 +237,7 @@ func (p *Client) ping() {
 	if p.sendPacket == 0 && p.recvPacket == 0 {
 		now := time.Now()
 		b, _ := now.MarshalBinary()
-		sendICMP(*p.conn, p.ipaddrServer, p.targetAddr, "", (uint32)(PING), b, p.sproto, p.rproto)
+		sendICMP(p.id, p.r.Intn(math.MaxInt16), *p.conn, p.ipaddrServer, p.targetAddr, "", (uint32)(PING), b, p.sproto, p.rproto)
 		fmt.Printf("ping %s %s %d %d\n", p.addrServer, now.String(), p.sproto, p.rproto)
 	}
 }
diff --git a/pingtunnel.go b/pingtunnel.go
index 2a3b1dd..71ee706 100644
--- a/pingtunnel.go
+++ b/pingtunnel.go
@@ -125,7 +125,7 @@ func (p *MyMsg) UnmarshalData(b []byte) []byte {
 	return data
 }
 
-func sendICMP(conn icmp.PacketConn, server *net.IPAddr, target string, connId string, msgType uint32, data []byte, sproto int, rproto int) {
+func sendICMP(id int, sequence int, conn icmp.PacketConn, server *net.IPAddr, target string, connId string, msgType uint32, data []byte, sproto int, rproto int) {
 
 	m := &MyMsg{
 		ID:      connId,
@@ -136,10 +136,18 @@ func sendICMP(conn icmp.PacketConn, server *net.IPAddr, target string, connId st
 		ENDTYPE: END,
 	}
 
+	mb, err := m.Marshal(0)
+
+	body := &icmp.Echo{
+		ID:   id,
+		Seq:  sequence,
+		Data: mb,
+	}
+
 	msg := &icmp.Message{
 		Type: (ipv4.ICMPType)(sproto),
 		Code: 0,
-		Body: m,
+		Body: body,
 	}
 
 	bytes, err := msg.Marshal(nil)
@@ -184,7 +192,7 @@ func recvICMP(conn icmp.PacketConn, recv chan<- *Packet) {
 
 		my := &MyMsg{
 		}
-		my.Unmarshal(bytes[4:n])
+		my.Unmarshal(bytes[8:n])
 
 		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)
diff --git a/server.go b/server.go
index ab17829..f0179af 100644
--- a/server.go
+++ b/server.go
@@ -3,17 +3,25 @@ package pingtunnel
 import (
 	"fmt"
 	"golang.org/x/net/icmp"
+	"math"
+	"math/rand"
 	"net"
 	"time"
 )
 
 func NewServer(timeout int) (*Server, error) {
+	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 	return &Server{
+		id:      r.Intn(math.MaxInt16),
+		r:       r,
 		timeout: timeout,
 	}, nil
 }
 
 type Server struct {
+	id int
+	r  *rand.Rand
+
 	timeout int
 
 	conn *icmp.PacketConn
@@ -69,7 +77,7 @@ func (p *Server) processPacket(packet *Packet) {
 		t := time.Time{}
 		t.UnmarshalBinary(packet.data)
 		fmt.Printf("ping from %s %s %d\n", packet.src.String(), t.String(), packet.rproto)
-		sendICMP(*p.conn, packet.src, "", "", (uint32)(PING), packet.data, packet.rproto, -1)
+		sendICMP(p.id, p.r.Intn(math.MaxInt16), *p.conn, packet.src, "", "", (uint32)(PING), packet.data, packet.rproto, -1)
 		return
 	}
 
@@ -136,7 +144,7 @@ func (p *Server) Recv(conn *ServerConn, id string, src *net.IPAddr) {
 		now := time.Now()
 		conn.activeTime = now
 
-		sendICMP(*p.conn, src, "", id, (uint32)(DATA), bytes[:n], conn.rproto, -1)
+		sendICMP(p.id, p.r.Intn(math.MaxInt16), *p.conn, src, "", id, (uint32)(DATA), bytes[:n], conn.rproto, -1)
 
 		p.sendPacket++
 		p.sendPacketSize += (uint64)(n)