try fix: #67 fatal error: concurrent map read and map write

trace/icmp_ipv4.go

@@ -52,7 +52,9 @@ func (t *ICMPTracer) PrintFunc() {
 }
 
 func (t *ICMPTracer) Execute() (*Result, error) {
+	t.inflightRequestLock.Lock()
 	t.inflightRequest = make(map[int]chan Hop)
+	t.inflightRequestLock.Unlock()
 
 	if len(t.res.Hops) > 0 {
 		return &t.res, ErrTracerouteExecuted

trace/icmp_ipv6.go

@@ -53,7 +53,9 @@ func (t *ICMPTracerv6) PrintFunc() {
 }
 
 func (t *ICMPTracerv6) Execute() (*Result, error) {
+	t.inflightRequestLock.Lock()
 	t.inflightRequest = make(map[int]chan Hop)
+	t.inflightRequestLock.Unlock()
 
 	if len(t.res.Hops) > 0 {
 		return &t.res, ErrTracerouteExecuted

trace/tcp_ipv4.go

@@ -60,7 +60,10 @@ func (t *TCPTracer) Execute() (*Result, error) {
 	var cancel context.CancelFunc
 	t.ctx, cancel = context.WithCancel(context.Background())
 	defer cancel()
+	t.inflightRequestLock.Lock()
 	t.inflightRequest = make(map[int]chan Hop)
+	t.inflightRequestLock.Unlock()
+
 	t.final = -1
 
 	go t.listenICMP()
@@ -161,7 +164,7 @@ func (t *TCPTracer) listenTCP() {
 			if tcpLayer := packet.Layer(layers.LayerTypeTCP); tcpLayer != nil {
 				tcp, _ := tcpLayer.(*layers.TCP)
 				// 取得目标主机的Sequence Number
-
+				t.inflightRequestLock.Lock()
 				if ch, ok := t.inflightRequest[int(tcp.Ack-1)]; ok {
 					// 最后一跳
 					ch <- Hop{
@@ -169,6 +172,7 @@ func (t *TCPTracer) listenTCP() {
 						Address: msg.Peer,
 					}
 				}
+				t.inflightRequestLock.Unlock()
 			}
 		}
 	}

trace/udp.go

@@ -121,8 +121,8 @@ func (t *UDPTracer) handleICMPMessage(msg ReceivedMessage, data []byte) {
 		return
 	}
 	srcPort := util.GetUDPSrcPort(header)
-	//t.inflightRequestLock.Lock()
-	//defer t.inflightRequestLock.Unlock()
+	t.inflightRequestLock.Lock()
+	defer t.inflightRequestLock.Unlock()
 	ch, ok := t.inflightRequest[int(srcPort)]
 	if !ok {
 		return