From 6e4d970dae2e292e4155174f5de13f7e774384a3 Mon Sep 17 00:00:00 2001
From: Dan Lake
Date: Mon, 18 Apr 2011 16:48:49 -0700
Subject: Requeue unacknowledged entity updates rather than resend then "as
 is". Often, by the time the UDPServer realizes that an entity update packet
 has not been acknowledged, there is a newer update for the same entity
 already queued up or there is a higher priority update that should be sent
 first. This patch eliminates 1:1 packet resends for unacked entity update
 packets. Insteawd, unacked update packets are decomposed into the original
 entity updates and those updates are placed back into the priority queues
 based on their new priority but the original update timestamp. This will
 generally place them at the head of the line to be put back on the wire as a
 new outgoing packet but prevents the resend queue from filling up with
 multiple stale updates for the same entity. This new approach takes advantage
 of the UDP nature of the Linden protocol in that the intent of a reliable
 update packet is that if it goes unacknowledge, SOMETHING has to happen to
 get the update to the client. We are simply making sure that we are resending
 current object state rather than stale object state.

Additionally, this patch includes a generalized callback mechanism so
that any caller can specify their own method to call when a packet
expires without being acknowledged. We use this mechanism to requeue
update packets and otherwise use the UDPServer default method of just
putting expired packets in the resend queue.
---
 OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs')

diff --git a/OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs b/OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs
index 1a1a1cb..f4f024b 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/OutgoingPacket.cs
@@ -31,6 +31,7 @@ using OpenMetaverse;
 
 namespace OpenSim.Region.ClientStack.LindenUDP
 {
+    public delegate void UnackedPacketMethod();
     /// <summary>
     /// Holds a reference to the <seealso cref="LLUDPClient"/> this packet is
     /// destined for, along with the serialized packet data, sequence number
@@ -52,6 +53,8 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         public int TickCount;
         /// <summary>Category this packet belongs to</summary>
         public ThrottleOutPacketType Category;
+        /// <summary>The delegate to be called if this packet is determined to be unacknowledged</summary>
+        public UnackedPacketMethod UnackedMethod;
 
         /// <summary>
         /// Default constructor
@@ -60,11 +63,12 @@ namespace OpenSim.Region.ClientStack.LindenUDP
         /// <param name="buffer">Serialized packet data. If the flags or sequence number
         /// need to be updated, they will be injected directly into this binary buffer</param>
         /// <param name="category">Throttling category for this packet</param>
-        public OutgoingPacket(LLUDPClient client, UDPPacketBuffer buffer, ThrottleOutPacketType category)
+        public OutgoingPacket(LLUDPClient client, UDPPacketBuffer buffer, ThrottleOutPacketType category, UnackedPacketMethod method)
         {
             Client = client;
             Buffer = buffer;
             Category = category;
+            UnackedMethod = method;
         }
     }
 }
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