From 1c63f6cd850a76b269df81aa89de17429c65ad60 Mon Sep 17 00:00:00 2001
From: John Hurliman <jhurliman@jhurliman.org>
Date: Fri, 2 Apr 2010 16:25:14 -0700
Subject: [PATCH] Don't append ACKs to zerocoded packets. Although this should
 fine in theory, I'm seeing the viewer ignore or fail to parse ACKs appended
 to our zerocoded packets. This should cut down on viewer->sim resend traffic

---
 .../ClientStack/LindenUDP/LLUDPServer.cs      | 35 +++++++++++--------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
index 3c4fa72363..5ed4cd7eb9 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
@@ -513,6 +513,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             byte flags = buffer.Data[0];
             bool isResend = (flags & Helpers.MSG_RESENT) != 0;
             bool isReliable = (flags & Helpers.MSG_RELIABLE) != 0;
+            bool isZerocoded = (flags & Helpers.MSG_ZEROCODED) != 0;
             LLUDPClient udpClient = outgoingPacket.Client;
 
             if (!udpClient.IsConnected)
@@ -522,23 +523,27 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             int dataLength = buffer.DataLength;
 
-            // Keep appending ACKs until there is no room left in the buffer or there are
-            // no more ACKs to append
-            uint ackCount = 0;
-            uint ack;
-            while (dataLength + 5 < buffer.Data.Length && udpClient.PendingAcks.Dequeue(out ack))
+            // NOTE: I'm seeing problems with some viewers when ACKs are appended to zerocoded packets so I've disabled that here
+            if (!isZerocoded)
             {
-                Utils.UIntToBytesBig(ack, buffer.Data, dataLength);
-                dataLength += 4;
-                ++ackCount;
-            }
+                // Keep appending ACKs until there is no room left in the buffer or there are
+                // no more ACKs to append
+                uint ackCount = 0;
+                uint ack;
+                while (dataLength + 5 < buffer.Data.Length && udpClient.PendingAcks.Dequeue(out ack))
+                {
+                    Utils.UIntToBytesBig(ack, buffer.Data, dataLength);
+                    dataLength += 4;
+                    ++ackCount;
+                }
 
-            if (ackCount > 0)
-            {
-                // Set the last byte of the packet equal to the number of appended ACKs
-                buffer.Data[dataLength++] = (byte)ackCount;
-                // Set the appended ACKs flag on this packet
-                buffer.Data[0] = (byte)(buffer.Data[0] | Helpers.MSG_APPENDED_ACKS);
+                if (ackCount > 0)
+                {
+                    // Set the last byte of the packet equal to the number of appended ACKs
+                    buffer.Data[dataLength++] = (byte)ackCount;
+                    // Set the appended ACKs flag on this packet
+                    buffer.Data[0] = (byte)(buffer.Data[0] | Helpers.MSG_APPENDED_ACKS);
+                }
             }
 
             buffer.DataLength = dataLength;