1 files changed, 29 insertions, 10 deletions

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
index 545a0bc..8bfab6a 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
@@ -89,6 +89,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
     /// </summary>
     public class LLUDPServer : OpenSimUDPBase
     {
+        /// <summary>Maximum transmission unit, or UDP packet size, for the LLUDP protocol</summary>
+        public const int MTU = 1400;
+
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 
         /// <summary>Handlers for incoming packets</summary>
@@ -267,38 +270,54 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         {
             int dataLength = data.Length;
             bool doZerocode = (data[0] & Helpers.MSG_ZEROCODED) != 0;
+            bool doCopy = true;
 
             // Frequency analysis of outgoing packet sizes shows a large clump of packets at each end of the spectrum.
             // The vast majority of packets are less than 200 bytes, although due to asset transfers and packet splitting
             // there are a decent number of packets in the 1000-1140 byte range. We allocate one of two sizes of data here
             // to accomodate for both common scenarios and provide ample room for ACK appending in both
-            int bufferSize = (dataLength > 180) ? Packet.MTU : 200;
+            int bufferSize = (dataLength > 180) ? LLUDPServer.MTU : 200;
 
             UDPPacketBuffer buffer = new UDPPacketBuffer(udpClient.RemoteEndPoint, bufferSize);
 
             // Zerocode if needed
             if (doZerocode)
             {
-                try { dataLength = Helpers.ZeroEncode(data, dataLength, buffer.Data); }
+                try
+                {
+                    dataLength = Helpers.ZeroEncode(data, dataLength, buffer.Data);
+                    doCopy = false;
+                }
                 catch (IndexOutOfRangeException)
                 {
                     // The packet grew larger than the bufferSize while zerocoding.
                     // Remove the MSG_ZEROCODED flag and send the unencoded data
                     // instead
-                    m_log.Debug("[LLUDPSERVER]: Packet exceeded buffer size during zerocoding for " + type + ". Removing MSG_ZEROCODED flag");
+                    m_log.Debug("[LLUDPSERVER]: Packet exceeded buffer size during zerocoding for " + type + ". DataLength=" + dataLength +
+                        " and BufferLength=" + buffer.Data.Length + ". Removing MSG_ZEROCODED flag");
                     data[0] = (byte)(data[0] & ~Helpers.MSG_ZEROCODED);
-                    Buffer.BlockCopy(data, 0, buffer.Data, 0, dataLength);
                 }
             }
-            else
+
+            // If the packet data wasn't already copied during zerocoding, copy it now
+            if (doCopy)
             {
-                Buffer.BlockCopy(data, 0, buffer.Data, 0, dataLength);
+                if (dataLength <= buffer.Data.Length)
+                {
+                    Buffer.BlockCopy(data, 0, buffer.Data, 0, dataLength);
+                }
+                else
+                {
+                    m_log.Error("[LLUDPSERVER]: Packet exceeded buffer size! This could be an indication of packet assembly not obeying the MTU. Type=" +
+                        type + ", DataLength=" + dataLength + ", BufferLength=" + buffer.Data.Length + ". Dropping packet");
+                    return;
+                }
             }
+
             buffer.DataLength = dataLength;
 
             #region Queue or Send
 
-            // Look up the UDPClient this is going to
             OutgoingPacket outgoingPacket = new OutgoingPacket(udpClient, buffer, category);
 
             if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket))
@@ -513,7 +532,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             IClientAPI client;
             if (!m_scene.ClientManager.TryGetValue(address, out client) || !(client is LLClientView))
             {
-                m_log.Warn("[LLUDPSERVER]: Received a " + packet.Type + " packet from an unrecognized source: " + address +
+                m_log.Debug("[LLUDPSERVER]: Received a " + packet.Type + " packet from an unrecognized source: " + address +
                     " in " + m_scene.RegionInfo.RegionName + ", currently tracking " + m_scene.ClientManager.Count + " clients");
                 return;
             }
@@ -568,9 +587,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             // client.BytesSinceLastACK. Lockless thread safety
             int bytesSinceLastACK = Interlocked.Exchange(ref udpClient.BytesSinceLastACK, 0);
             bytesSinceLastACK += buffer.DataLength;
-            if (bytesSinceLastACK > Packet.MTU * 2)
+            if (bytesSinceLastACK > LLUDPServer.MTU * 2)
             {
-                bytesSinceLastACK -= Packet.MTU * 2;
+                bytesSinceLastACK -= LLUDPServer.MTU * 2;
                 SendAcks(udpClient);
             }
             Interlocked.Add(ref udpClient.BytesSinceLastACK, bytesSinceLastACK);