Store in TCP conns the real ephemeral port and not the listening port

Related to #1692

(cherry picked from commit 929c854)

net/net_tcp.c

@@ -834,6 +834,8 @@ static struct tcp_connection* tcpconn_new(int sock, union sockaddr_union* su,
 							struct socket_info* si, int state, int flags)
 {
 	struct tcp_connection *c;
+	union sockaddr_union local_su;
+	unsigned int su_size;
 
 	c=(struct tcp_connection*)shm_malloc(sizeof(struct tcp_connection));
 	if (c==0){
@@ -855,7 +857,9 @@ static struct tcp_connection* tcpconn_new(int sock, union sockaddr_union* su,
 	c->rcv.src_port=su_getport(su);
 	c->rcv.bind_address = si;
 	c->rcv.dst_ip = si->address;
-	c->rcv.dst_port = si->port_no;
+	su_size = sockaddru_len(local_su);
+	getsockname(sock, (struct sockaddr *)&local_su, &su_size);
+	c->rcv.dst_port = su_getport(&local_su);
 	print_ip("tcpconn_new: new tcp connection to: ", &c->rcv.src_ip, "\n");
 	LM_DBG("on port %d, proto %d\n", c->rcv.src_port, si->proto);
 	c->id=(*connection_id)++;