From 3b1b3ac9bbd77796a55bcc75d08f78bff5ca78af Mon Sep 17 00:00:00 2001
From: Adam Frisby
Date: Sat, 23 May 2009 05:44:18 +0000
Subject: * Breaks OpenSim.. err I mean.. adds NAT translation support to
 EnableSimulator EventQueue methods. * NB: This may actually break logins on
 certain regions. Shake well before consuming.

---
 OpenSim/Framework/NetworkUtil.cs | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

(limited to 'OpenSim/Framework/NetworkUtil.cs')

diff --git a/OpenSim/Framework/NetworkUtil.cs b/OpenSim/Framework/NetworkUtil.cs
index 759c52f..81e6cad 100644
--- a/OpenSim/Framework/NetworkUtil.cs
+++ b/OpenSim/Framework/NetworkUtil.cs
@@ -14,11 +14,49 @@ namespace OpenSim.Framework
     /// This enables standard port forwarding techniques
     /// to work correctly with OpenSim.
     /// </summary>
-    static class NetworkUtil
+    public static class NetworkUtil
     {
         // IPv4Address, Subnet
         static readonly Dictionary<IPAddress,IPAddress> m_subnets = new Dictionary<IPAddress, IPAddress>();
 
+        public static IPAddress GetIPFor(IPAddress user, IPAddress simulator)
+        {
+            // Check if we're accessing localhost.
+            foreach (IPAddress host in Dns.GetHostAddresses(Dns.GetHostName()))
+            {
+                if (host.Equals(user) && host.AddressFamily == AddressFamily.InterNetwork)
+                    return host;
+            }
+
+            // Check for same LAN segment
+            foreach (KeyValuePair<IPAddress, IPAddress> subnet in m_subnets)
+            {
+                byte[] subnetBytes = subnet.Value.GetAddressBytes();
+                byte[] localBytes = subnet.Key.GetAddressBytes();
+                byte[] destBytes = user.GetAddressBytes();
+
+                if (subnetBytes.Length != destBytes.Length || subnetBytes.Length != localBytes.Length)
+                    return null;
+
+                bool valid = true;
+
+                for (int i = 0; i < subnetBytes.Length; i++)
+                {
+                    if ((localBytes[i] & subnetBytes[i]) != (destBytes[i] & subnetBytes[i]))
+                    {
+                        valid = false;
+                        break;
+                    }
+                }
+
+                if (valid)
+                    return subnet.Key;
+            }
+
+            // Otherwise, return outside address
+            return simulator;
+        }
+
         private static IPAddress GetExternalIPFor(IPAddress destination, string defaultHostname)
         {
             // Adds IPv6 Support (Not that any of the major protocols supports it...)
-- 
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