Nerf protocol window sizes

src/network/connection.cpp

@@ -751,6 +751,7 @@ void Channel::UpdateTimers(float dtime)
 			packet_too_late = current_packet_too_late;
 			packets_successful = current_packet_successful;
 
+			// has half the window even been used?
 			if (current_bytes_transfered > (unsigned int) (m_window_size*512/2)) {
 				reasonable_amount_of_data_transmitted = true;
 			}

src/network/connection_internal.h

@@ -329,15 +329,24 @@ private:
 	static ConnectionCommandPtr create(ConnectionCommandType type);
 };
 
-/* maximum window size to use, 0xFFFF is theoretical maximum. don't think about
+/*
+ * Window sizes to use, in packets (not bytes!).
+ * 0xFFFF is theoretical maximum. don't think about
  * touching it, the less you're away from it the more likely data corruption
  * will occur
+ *
+ * Note: window sizes directly translate to maximum possible throughput, e.g.
+ *       (2048 * 512 bytes) / 33ms = 15 MiB/s
  */
+
+// Due to backwards compatibility we have different window sizes for what we'll
+// accept from peers vs. what we use for sending.
 #define MAX_RELIABLE_WINDOW_SIZE 0x8000
+#define MAX_RELIABLE_WINDOW_SIZE_SEND 2048
 /* starting value for window size */
-#define START_RELIABLE_WINDOW_SIZE 0x400
+#define START_RELIABLE_WINDOW_SIZE 64
 /* minimum value for window size */
-#define MIN_RELIABLE_WINDOW_SIZE 0x40
+#define MIN_RELIABLE_WINDOW_SIZE 32
 
 class Channel
 {
@@ -405,7 +414,7 @@ public:
 
 	void setWindowSize(long size)
 	{
-		m_window_size = (u16)rangelim(size, MIN_RELIABLE_WINDOW_SIZE, MAX_RELIABLE_WINDOW_SIZE);
+		m_window_size = (u16)rangelim(size, MIN_RELIABLE_WINDOW_SIZE, MAX_RELIABLE_WINDOW_SIZE_SEND);
 	}
 
 private:

src/network/connectionthreads.cpp

@@ -317,6 +317,7 @@ void ConnectionSendThread::sendAsPacketReliable(BufferedPacketPtr &p, Channel *c
 		channel->outgoing_reliables_sent.insert(p,
 			(channel->readOutgoingSequenceNumber() - MAX_RELIABLE_WINDOW_SIZE)
 				% (MAX_RELIABLE_WINDOW_SIZE + 1));
+		// wtf is this calculation?? ^
 	}
 	catch (AlreadyExistsException &e) {
 		LOG(derr_con << m_connection->getDesc()