add warning when packet is truncated

ISSUE_TEMPLATE.md

@@ -1,6 +1 @@
-For English speaking user：
-https://github.com/wangyu-/UDPspeeder/wiki/Issue-Guide
-
-中文用户请看：
-https://github.com/wangyu-/UDPspeeder/wiki/发Issue前请看
-(否则Issue可能被忽略，或被直接关掉)
+English Only (except for bug reporting).

tunnel_client.cpp

@@ -44,12 +44,18 @@ void data_from_local_or_fec_timeout(conn_info_t & conn_info,int is_time_out)
 		mylog(log_trace,"events[idx].data.u64 == (u64_t)local_listen_fd\n");
 		address_t::storage_t udp_new_addr_in={0};
 		socklen_t udp_new_addr_len = sizeof(address_t::storage_t);
-		if ((data_len = recvfrom(local_listen_fd, data, max_data_len, 0,
+		if ((data_len = recvfrom(local_listen_fd, data, max_data_len+1, 0,
 				(struct sockaddr *) &udp_new_addr_in, &udp_new_addr_len)) == -1) {
 			mylog(log_debug,"recv_from error,this shouldnt happen,err=%s,but we can try to continue\n",get_sock_error());
 			return;
 		};
 
+		if(data_len==max_data_len+1)
+		{
+			mylog(log_warn,"huge packet, data_len > %d, packet truncated, dropped\n",max_data_len);
+			return ;
+		}
+
 		if(!disable_mtu_warn&&data_len>=mtu_warn)
 		{
 			mylog(log_warn,"huge packet,data len=%d (>=%d).strongly suggested to set a smaller mtu at upper level,to get rid of this warn\n ",data_len,mtu_warn);
@@ -122,7 +128,15 @@ static void remote_cb(struct ev_loop *loop, struct ev_io *watcher, int revents)
 
 	int fd=fd_manager.to_fd(remote_fd64);
 
-	int data_len =recv(fd,data,max_data_len,0);
+	int data_len =recv(fd,data,max_data_len+1,0);
+
+	if(data_len==max_data_len+1)
+        {
+                mylog(log_warn,"huge packet, data_len > %d, packet truncated, dropped\n",max_data_len);
+                return ;
+        }
+
+
 	mylog(log_trace, "received data from udp fd %d, len=%d\n", remote_fd,data_len);
 	if(data_len<0)
 	{

tunnel_server.cpp

@@ -89,7 +89,13 @@ void data_from_remote_or_fec_timeout_or_conn_timer(conn_info_t & conn_info,fd64_
 		conn_info.update_active_time();
 
 		int fd=fd_manager.to_fd(fd64);
-		data_len=recv(fd,data,max_data_len,0);
+		data_len=recv(fd,data,max_data_len+1,0);
+
+		if(data_len==max_data_len+1)
+		{
+			mylog(log_warn,"huge packet, data_len > %d, packet truncated, dropped\n",max_data_len);
+			return ;
+		}
 
 		mylog(log_trace,"received a packet from udp_fd,len:%d,conv=%d\n",data_len,conv);
 
@@ -135,12 +141,18 @@ static void local_listen_cb(struct ev_loop *loop, struct ev_io *watcher, int rev
 	int data_len;
 	address_t::storage_t udp_new_addr_in={0};
 	socklen_t udp_new_addr_len = sizeof(address_t::storage_t);
-	if ((data_len = recvfrom(local_listen_fd, data, max_data_len, 0,
+	if ((data_len = recvfrom(local_listen_fd, data, max_data_len+1, 0,
 			(struct sockaddr *) &udp_new_addr_in, &udp_new_addr_len)) == -1) {
 		mylog(log_error,"recv_from error,this shouldnt happen,err=%s,but we can try to continue\n",get_sock_error());
 		return;
 	};
 
+	if(data_len==max_data_len+1)
+        {
+                mylog(log_warn,"huge packet, data_len > %d, packet truncated, dropped\n",max_data_len);
+                return ;
+        }
+
 	address_t addr;
 	addr.from_sockaddr((struct sockaddr *) &udp_new_addr_in,udp_new_addr_len);