[ENet-discuss] ENet bug: in enet_protocol_handle_send_fragment(...)

[Lee Salzman]

Sharp eyes. I can't believe I missed that. I'm almost embarrassed. :)

I committed a fix for this to CVS and included it in the main tarball.

Lee

On Wed, Aug 13, 2003 at 08:40:45AM +0900, ?????? wrote:
> Hi,
> I found an error in protocol.c' enet_protocol_handle_send_fragment()
> 
> original codes are:
> 
> 	for (currentCommand = enet_list_previous(enet_list_end(&channel->incomingReliableCommands));
> 	      currentCommand !=enet_list_end(&channel->incomingReliableCommands);
> 	      currentCommand = enet_list_previous(currentCommand)) {
> 	       startCommand = (ENetIncomingCommand *) currentCommand;
> 	       if (startCommand->reliableSequenceNumber == startSequenceNumber) {
> 	           break;
>              }
> 
> The lines could not handle if the first fragment of a fragmented message is lost.
> For example, consider that an user message is fragmented into more than two fragments and
> the receiver lost the first fragment at first time and received the second fragment and then the first fragment which 
> is retransmitted by the sender.
> In this case the second fragment and the first one are considered as a separate message.
> User can get no more message if this situation occurs.
> 
> So, I changed the code lines as follows:
> 
> 	for (currentCommand = enet_list_previous(enet_list_end(&channel->incomingReliableCommands));
> 	      currentCommand !=enet_list_end(&channel->incomingReliableCommands);
> 	      currentCommand = enet_list_previous(currentCommand)) {
> 	       startCommand = (ENetIncomingCommand *) currentCommand;
> 	       if (startCommand->reliableSequenceNumber == startSequenceNumber) {
> 	           break;
> 	      /* NEWLY ADDED LINES! to handle reversly received fragments */
>        	      if (startCommand->reliableSequenceNumber > startSequenceNumber ) {
>            		ENetProtocol    *anchor = (ENetProtocol *)&startCommand->command;
> 		/* check if the startCommand belongs to the same message */
>            		if (anchor->sendFragment.startSequenceNumber == startSequenceNumber)
> 	                  break;
> 
>        	      }
>              }
> 
> The code worked fine to me.
> Hope useful.
> PS) Sorry. I could not add diff output because I added so many debug lines in enet. ;-)
> 
> ---------------
> Won
>