From ac0acb02962c37f870dc38a356e1530803f699e8 Mon Sep 17 00:00:00 2001
From: John Hurliman <jhurliman@jhurliman.org>
Date: Fri, 23 Oct 2009 01:33:05 -0700
Subject: [PATCH] * Changed the max RTO value to 60 seconds to comply with RFC
 2988 * Implemented section 5.5, exponential backoff of the RTO after a resend

---
 OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs | 2 +-
 OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
index 460938e2bd..d2cd6d90ea 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
@@ -500,7 +500,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             RTO = (int)(SRTT + Math.Max(m_udpServer.TickCountResolution, K * RTTVAR));
 
             // Clamp the retransmission timeout to manageable values
-            RTO = Utils.Clamp(RTO, 3000, 10000);
+            RTO = Utils.Clamp(RTO, 3000, 60000);
 
             //m_log.Debug("[LLUDPCLIENT]: Setting agent " + this.Agent.FullName + "'s RTO to " + RTO + "ms with an RTTVAR of " +
             //    RTTVAR + " based on new RTT of " + r + "ms");
diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
index 2973d4b68c..7e929e52b6 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
@@ -407,6 +407,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             {
                 //m_log.Debug("[LLUDPSERVER]: Resending " + expiredPackets.Count + " packets to " + udpClient.AgentID + ", RTO=" + udpClient.RTO);
 
+                // Backoff the RTO
+                udpClient.RTO = Math.Min(udpClient.RTO * 2, 60000);
+
                 // Resend packets
                 for (int i = 0; i < expiredPackets.Count; i++)
                 {