Loop through rebound packets until you found a good one or ran out of them

src/d_net.c

@@ -1124,6 +1124,10 @@ boolean HGetPacket(void)
 	// Get a packet from self
 	if (rebound_tail != rebound_head)
 	{
+		while (true) // loop until we found a valid packet, or we ran out of packets
+		{ // provided MAXREBOUND is not all that large this shouldn't take too long
+			if (rebound_tail == rebound_head)
+				break; // just give up, none of them were any good somehow
 			M_Memcpy(netbuffer, &reboundstore[rebound_tail], reboundsize[rebound_tail]);
 			doomcom->datalength = reboundsize[rebound_tail];
 			if (netbuffer->packettype == PT_NODETIMEOUT)
@@ -1134,13 +1138,14 @@ boolean HGetPacket(void)
 			rebound_tail = (rebound_tail+1) % MAXREBOUND;
 
 			if (doomcom->remotenode == -1) // wait hang on what?
-			return true; // there might still be packets from others though, so don't return false
+				continue; // ignore it, look for the next packet
 #ifdef DEBUGFILE
 			if (debugfile)
 				DebugPrintpacket("GETLOCAL");
 #endif
 			return true;
 		}
+	}
 
 	if (!netgame)
 		return false;