1 files changed, 250 insertions, 0 deletions

diff --git a/OpenSim/Framework/NetworkUtil.cs b/OpenSim/Framework/NetworkUtil.cs
new file mode 100644
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+++ b/OpenSim/Framework/NetworkUtil.cs
@@ -0,0 +1,250 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Net.Sockets;
+using System.Net;
+using System.Net.NetworkInformation;
+using System.Reflection;
+using System.Text;
+using log4net;
+
+namespace OpenSim.Framework
+{
+    /// <summary>
+    /// Handles NAT translation in a 'manner of speaking'
+    /// Allows you to return multiple different external
+    /// hostnames depending on the requestors network
+    /// 
+    /// This enables standard port forwarding techniques
+    /// to work correctly with OpenSim.
+    /// </summary>
+    public static class NetworkUtil
+    {
+        // Logger
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+        private static bool m_disabled = true;
+
+        public static bool Enabled
+        {
+            set { m_disabled = value; }
+            get { return m_disabled; }
+        }
+
+        // IPv4Address, Subnet
+        static readonly Dictionary<IPAddress,IPAddress> m_subnets = new Dictionary<IPAddress, IPAddress>();
+
+        public static IPAddress GetIPFor(IPAddress user, IPAddress simulator)
+        {
+            if (m_disabled)
+                return simulator;
+
+            // Check if we're accessing localhost.
+            foreach (IPAddress host in Dns.GetHostAddresses(Dns.GetHostName()))
+            {
+                if (host.Equals(user) && host.AddressFamily == AddressFamily.InterNetwork)
+                {
+                    m_log.Info("[NetworkUtil] Localhost user detected, sending them '" + host + "' instead of '" + simulator + "'");
+                    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 (subnet.Key.AddressFamily != AddressFamily.InterNetwork)
+                    valid = false;
+
+                if (valid)
+                {
+                    m_log.Info("[NetworkUtil] Local LAN user detected, sending them '" + subnet.Key + "' instead of '" + simulator + "'");
+                    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...)
+            if (destination.AddressFamily == AddressFamily.InterNetworkV6)
+            {
+                foreach (IPAddress host in Dns.GetHostAddresses(defaultHostname))
+                {
+                    if (host.AddressFamily == AddressFamily.InterNetworkV6)
+                    {
+                        m_log.Info("[NetworkUtil] Localhost user detected, sending them '" + host + "' instead of '" + defaultHostname + "'");
+                        return host;
+                    }
+                }
+            }
+
+            if (destination.AddressFamily != AddressFamily.InterNetwork)
+                return null;
+
+            // Check if we're accessing localhost.
+            foreach (KeyValuePair<IPAddress, IPAddress> pair in m_subnets)
+            {
+                IPAddress host = pair.Value;
+                if (host.Equals(destination) && host.AddressFamily == AddressFamily.InterNetwork)
+                {
+                    m_log.Info("[NATROUTING] Localhost user detected, sending them '" + host + "' instead of '" + defaultHostname + "'");
+                    return destination;
+                }
+            }
+
+            // 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 = destination.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 (subnet.Key.AddressFamily != AddressFamily.InterNetwork)
+                    valid = false;
+
+                if (valid)
+                {
+                    m_log.Info("[NetworkUtil] Local LAN user detected, sending them '" + subnet.Key + "' instead of '" + defaultHostname + "'");
+                    return subnet.Key;
+                }
+            }
+
+            // Check to see if we can find a IPv4 address.
+            foreach (IPAddress host in Dns.GetHostAddresses(defaultHostname))
+            {
+                if (host.AddressFamily == AddressFamily.InterNetwork)
+                    return host;
+            }
+
+            // Unable to find anything.
+            throw new ArgumentException("[NetworkUtil] Unable to resolve defaultHostname to an IPv4 address for an IPv4 client");
+        }
+
+        static NetworkUtil()
+        {
+            try
+            {
+                foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
+                {
+                    foreach (UnicastIPAddressInformation address in ni.GetIPProperties().UnicastAddresses)
+                    {
+                        if (address.Address.AddressFamily == AddressFamily.InterNetwork)
+                        {
+                            if (address.IPv4Mask != null)
+                            {
+                                m_subnets.Add(address.Address, address.IPv4Mask);
+                            }
+                        }
+                    }
+                }
+            }
+            catch (NotImplementedException)
+            {
+                // Mono Sucks.
+            }
+        }
+
+        public static IPAddress GetIPFor(IPEndPoint user, string defaultHostname)
+        {
+            if (!m_disabled)
+            {
+                // Try subnet matching
+                IPAddress rtn = GetExternalIPFor(user.Address, defaultHostname);
+                if (rtn != null)
+                    return rtn;
+            }
+
+            // Otherwise use the old algorithm
+            IPAddress ia;
+
+            if (IPAddress.TryParse(defaultHostname, out ia))
+                return ia;
+
+            ia = null;
+
+            foreach (IPAddress Adr in Dns.GetHostAddresses(defaultHostname))
+            {
+                if (Adr.AddressFamily == AddressFamily.InterNetwork)
+                {
+                    ia = Adr;
+                    break;
+                }
+            }
+
+            return ia;
+        }
+
+        public static string GetHostFor(IPAddress user, string defaultHostname)
+        {
+            if (!m_disabled)
+            {
+                IPAddress rtn = GetExternalIPFor(user, defaultHostname);
+                if (rtn != null)
+                    return rtn.ToString();
+            }
+            return defaultHostname;
+        }
+
+    }
+}