New Teleport protocol (V2), still compatible with V1 and older. (version of the destination is being checked)

In this new protocol, and as committed before, the viewer is not sent EnableSimulator/EstablishChildCommunication for the destination. Instead, it is sent TeleportFinish directly. TeleportFinish, in turn, makes the viewer send a UserCircuitCode packet followed by CompleteMovementIntoRegion packet. These 2 packets tend to occur one after the other almost immediately to the point that when CMIR arrives the client is not even connected yet and that packet is ignored (there might have been some race conditions here before); then the viewer sends CMIR again within 5-8 secs. But the delay between them may be higher in busier regions, which may lead to race conditions.
This commit improves the process so there are are no race conditions at the destination. CompleteMovement (triggered by the viewer) waits until Update has been sent from the origin. Update, in turn, waits until there is a *root* scene presence -- so making sure CompleteMovement has run MakeRoot. In other words, there are two threadlets at the destination, one from the viewer and one from the origin region, waiting for each other to do the right thing. That makes it safe to close the agent at the origin upon return of the Update call without having to wait for callback, because we are absolutely sure that the viewer knows it is in th new region.
Note also that in the V1 protocol, the destination was getting UseCircuitCode from the viewer twice -- once on EstablishAgentCommunication and then again on TeleportFinish. The second UCC was being ignored, but it shows how we were not following the expected steps...

1 files changed, 68 insertions, 0 deletions

diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
index 37fd252..1b72b26 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLUDPServer.cs
@@ -1257,6 +1257,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             // UseCircuitCode handling
             if (packet.Type == PacketType.UseCircuitCode)
             {
+                m_log.DebugFormat("[ZZZ]: In the dungeon: UseCircuitCode");
                 // We need to copy the endpoint so that it doesn't get changed when another thread reuses the
                 // buffer.
                 object[] array = new object[] { new IPEndPoint(endPoint.Address, endPoint.Port), packet };
@@ -1265,6 +1266,20 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                 return;
             }
+            else if (packet.Type == PacketType.CompleteAgentMovement)
+            {
+                // Send ack straight away to let the viewer know that we got it.
+                SendAckImmediate(endPoint, packet.Header.Sequence);
+
+                m_log.DebugFormat("[ZZZ]: In the dungeon: CompleteAgentMovement");
+                // We need to copy the endpoint so that it doesn't get changed when another thread reuses the
+                // buffer.
+                object[] array = new object[] { new IPEndPoint(endPoint.Address, endPoint.Port), packet };
+
+                Util.FireAndForget(HandleCompleteMovementIntoRegion, array);
+
+                return;
+            }
 
             // Determine which agent this packet came from
             IClientAPI client;
@@ -1604,6 +1619,56 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             }
         }
 
+        private void HandleCompleteMovementIntoRegion(object o)
+        {
+            IPEndPoint endPoint = null;
+            IClientAPI client = null;
+
+            try
+            {
+                object[] array = (object[])o;
+                endPoint = (IPEndPoint)array[0];
+                CompleteAgentMovementPacket packet = (CompleteAgentMovementPacket)array[1];
+
+                // Determine which agent this packet came from
+                int count = 10;
+                while (!m_scene.TryGetClient(endPoint, out client) && count-- > 0)
+                {
+                    m_log.Debug("[LLUDPSERVER]: Received a CompleteMovementIntoRegion in " + m_scene.RegionInfo.RegionName + " (not ready yet)");
+                    Thread.Sleep(200);
+                }
+
+                if (client == null)
+                    return;
+
+                IncomingPacket incomingPacket1;
+
+                // Inbox insertion
+                if (UsePools)
+                {
+                    incomingPacket1 = m_incomingPacketPool.GetObject();
+                    incomingPacket1.Client = (LLClientView)client;
+                    incomingPacket1.Packet = packet;
+                }
+                else
+                {
+                    incomingPacket1 = new IncomingPacket((LLClientView)client, packet);
+                }
+
+                packetInbox.Enqueue(incomingPacket1);
+            }
+            catch (Exception e)
+            {
+                m_log.ErrorFormat(
+                    "[LLUDPSERVER]: CompleteMovementIntoRegion handling from endpoint {0}, client {1} {2} failed.  Exception {3}{4}",
+                    endPoint != null ? endPoint.ToString() : "n/a",
+                    client != null ? client.Name : "unknown",
+                    client != null ? client.AgentId.ToString() : "unknown",
+                    e.Message,
+                    e.StackTrace);
+            }
+        }
+
         /// <summary>
         /// Send an ack immediately to the given endpoint.
         /// </summary>
@@ -1999,6 +2064,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             Packet packet = incomingPacket.Packet;
             LLClientView client = incomingPacket.Client;
 
+            if (packet is CompleteAgentMovementPacket)
+                m_log.DebugFormat("[ZZZ]: Received CompleteAgentMovementPacket");
+
             if (client.IsActive)
             {
                 m_currentIncomingClient = client;