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 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 * 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.IO;
using System.Net;
using System.Net.Security;
using System.Web;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Xml;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using OpenMetaverse;
using OpenMetaverse.StructuredData;
using log4net;
using Nini.Config;
using Nwc.XmlRpc;
using OpenSim.Framework;
using Mono.Addins;
using OpenSim.Framework.Capabilities;
using OpenSim.Framework.Servers;
using OpenSim.Framework.Servers.HttpServer;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;
using Caps = OpenSim.Framework.Capabilities.Caps;
using System.Text.RegularExpressions;
using OpenSim.Server.Base;
using OpenSim.Services.Interfaces;
using OSDMap = OpenMetaverse.StructuredData.OSDMap;
namespace OpenSim.Region.OptionalModules.Avatar.Voice.FreeSwitchVoice
{
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "FreeSwitchVoiceModule")]
    public class FreeSwitchVoiceModule : ISharedRegionModule, IVoiceModule
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
        // Capability string prefixes
        private static readonly string m_parcelVoiceInfoRequestPath = "0207/";
        private static readonly string m_provisionVoiceAccountRequestPath = "0208/";
        private static readonly string m_chatSessionRequestPath = "0209/";
        // Control info
        private static bool   m_Enabled  = false;
        // FreeSwitch server is going to contact us and ask us all
        // sorts of things.
        // SLVoice client will do a GET on this prefix
        private static string m_freeSwitchAPIPrefix;
        // We need to return some information to SLVoice
        // figured those out via curl
        // http://vd1.vivox.com/api2/viv_get_prelogin.php
        //
        // need to figure out whether we do need to return ALL of
        // these...
        private static string m_freeSwitchRealm;
        private static string m_freeSwitchSIPProxy;
        private static bool m_freeSwitchAttemptUseSTUN;
        private static string m_freeSwitchEchoServer;
        private static int m_freeSwitchEchoPort;
        private static string m_freeSwitchDefaultWellKnownIP;
        private static int m_freeSwitchDefaultTimeout;
        private static string m_freeSwitchUrlResetPassword;
        private uint m_freeSwitchServicePort;
        private string m_openSimWellKnownHTTPAddress;
//        private string m_freeSwitchContext;
        private readonly Dictionary<string, string> m_UUIDName = new Dictionary<string, string>();
        private Dictionary<string, string> m_ParcelAddress = new Dictionary<string, string>();
        private IConfig m_Config;
        private IFreeswitchService m_FreeswitchService;
        public void Initialise(IConfigSource config)
        {
            m_Config = config.Configs["FreeSwitchVoice"];
            if (m_Config == null)
                return;
            if (!m_Config.GetBoolean("Enabled", false))
                return;
            try
            {
                string serviceDll = m_Config.GetString("LocalServiceModule",
                        String.Empty);
                if (serviceDll == String.Empty)
                {
                    m_log.Error("[FreeSwitchVoice]: No LocalServiceModule named in section FreeSwitchVoice.  Not starting.");
                    return;
                }
                Object[] args = new Object[] { config };
                m_FreeswitchService = ServerUtils.LoadPlugin<IFreeswitchService>(serviceDll, args);
                string jsonConfig = m_FreeswitchService.GetJsonConfig();
                //m_log.Debug("[FreeSwitchVoice]: Configuration string: " + jsonConfig);
                OSDMap map = (OSDMap)OSDParser.DeserializeJson(jsonConfig);
                m_freeSwitchAPIPrefix = map["APIPrefix"].AsString();
                m_freeSwitchRealm = map["Realm"].AsString();
                m_freeSwitchSIPProxy = map["SIPProxy"].AsString();
                m_freeSwitchAttemptUseSTUN = map["AttemptUseSTUN"].AsBoolean();
                m_freeSwitchEchoServer = map["EchoServer"].AsString();
                m_freeSwitchEchoPort = map["EchoPort"].AsInteger();
                m_freeSwitchDefaultWellKnownIP = map["DefaultWellKnownIP"].AsString();
                m_freeSwitchDefaultTimeout = map["DefaultTimeout"].AsInteger();
                m_freeSwitchUrlResetPassword = String.Empty;
//                m_freeSwitchContext = map["Context"].AsString();
                if (String.IsNullOrEmpty(m_freeSwitchRealm) ||
                    String.IsNullOrEmpty(m_freeSwitchAPIPrefix))
                {
                    m_log.Error("[FreeSwitchVoice]: Freeswitch service mis-configured.  Not starting.");                    
                    return;
                }
                // set up http request handlers for
                // - prelogin: viv_get_prelogin.php
                // - signin: viv_signin.php
                // - buddies: viv_buddy.php
                // - ???: viv_watcher.php
                // - signout: viv_signout.php
                MainServer.Instance.AddHTTPHandler(String.Format("{0}/viv_get_prelogin.php", m_freeSwitchAPIPrefix),
                                                     FreeSwitchSLVoiceGetPreloginHTTPHandler);
                MainServer.Instance.AddHTTPHandler(String.Format("{0}/freeswitch-config", m_freeSwitchAPIPrefix), FreeSwitchConfigHTTPHandler);
                // RestStreamHandler h = new
                // RestStreamHandler("GET",
                // String.Format("{0}/viv_get_prelogin.php", m_freeSwitchAPIPrefix), FreeSwitchSLVoiceGetPreloginHTTPHandler);
                //  MainServer.Instance.AddStreamHandler(h);
                MainServer.Instance.AddHTTPHandler(String.Format("{0}/viv_signin.php", m_freeSwitchAPIPrefix),
                                 FreeSwitchSLVoiceSigninHTTPHandler);
                MainServer.Instance.AddHTTPHandler(String.Format("{0}/viv_buddy.php", m_freeSwitchAPIPrefix),
                                 FreeSwitchSLVoiceBuddyHTTPHandler);
                
                MainServer.Instance.AddHTTPHandler(String.Format("{0}/viv_watcher.php", m_freeSwitchAPIPrefix),
                                 FreeSwitchSLVoiceWatcherHTTPHandler);                
                m_log.InfoFormat("[FreeSwitchVoice]: using FreeSwitch server {0}", m_freeSwitchRealm);
                m_Enabled = true;
                m_log.Info("[FreeSwitchVoice]: plugin enabled");
            }
            catch (Exception e)
            {
                m_log.ErrorFormat("[FreeSwitchVoice]: plugin initialization failed: {0} {1}", e.Message, e.StackTrace);
                return;
            }
            // This here is a region module trying to make a global setting.
            // Not really a good idea but it's Windows only, so I can't test.
            try
            {
                ServicePointManager.ServerCertificateValidationCallback += CustomCertificateValidation;
            }
            catch (NotImplementedException)
            {
                try
                {
#pragma warning disable 0612, 0618
                    // Mono does not implement the ServicePointManager.ServerCertificateValidationCallback yet!  Don't remove this!
                    ServicePointManager.CertificatePolicy = new MonoCert();
#pragma warning restore 0612, 0618
                }
                catch (Exception)
                {
                    // COmmented multiline spam log message
                    //m_log.Error("[FreeSwitchVoice]: Certificate validation handler change not supported.  You may get ssl certificate validation errors teleporting from your region to some SSL regions.");
                }
            }
        }
        public void PostInitialise()
        {
        }
        public void AddRegion(Scene scene)
        {
            // We generate these like this: The region's external host name
            // as defined in Regions.ini is a good address to use. It's a
            // dotted quad (or should be!) and it can reach this host from
            // a client. The port is grabbed from the region's HTTP server.
            m_openSimWellKnownHTTPAddress = scene.RegionInfo.ExternalHostName;
            m_freeSwitchServicePort = MainServer.Instance.Port;
            if (m_Enabled)
            {
                // we need to capture scene in an anonymous method
                // here as we need it later in the callbacks
                scene.EventManager.OnRegisterCaps += delegate(UUID agentID, Caps caps)
                    {
                        OnRegisterCaps(scene, agentID, caps);
                    };
            }
        }
        public void RemoveRegion(Scene scene)
        {
        }
        public void RegionLoaded(Scene scene)
        {
            if (m_Enabled)
            {
                m_log.Info("[FreeSwitchVoice]: registering IVoiceModule with the scene");
                // register the voice interface for this module, so the script engine can call us
                scene.RegisterModuleInterface<IVoiceModule>(this);
            }
        }
        public void Close()
        {
        }
        public string Name
        {
            get { return "FreeSwitchVoiceModule"; }
        }
        public Type ReplaceableInterface
        {
            get { return null; }
        }
        // <summary>
        // implementation of IVoiceModule, called by osSetParcelSIPAddress script function
        // </summary>
        public void setLandSIPAddress(string SIPAddress,UUID GlobalID)
        {
            m_log.DebugFormat("[FreeSwitchVoice]: setLandSIPAddress parcel id {0}: setting sip address {1}",
                                  GlobalID, SIPAddress);
            lock (m_ParcelAddress)
            {
                if (m_ParcelAddress.ContainsKey(GlobalID.ToString()))
                {
                    m_ParcelAddress[GlobalID.ToString()] = SIPAddress;
                }
                else
                {
                    m_ParcelAddress.Add(GlobalID.ToString(), SIPAddress);
                }
            }
        }
        // <summary>
        // OnRegisterCaps is invoked via the scene.EventManager
        // everytime OpenSim hands out capabilities to a client
        // (login, region crossing). We contribute two capabilities to
        // the set of capabilities handed back to the client:
        // ProvisionVoiceAccountRequest and ParcelVoiceInfoRequest.
        //
        // ProvisionVoiceAccountRequest allows the client to obtain
        // the voice account credentials for the avatar it is
        // controlling (e.g., user name, password, etc).
        //
        // ParcelVoiceInfoRequest is invoked whenever the client
        // changes from one region or parcel to another.
        //
        // Note that OnRegisterCaps is called here via a closure
        // delegate containing the scene of the respective region (see
        // Initialise()).
        // </summary>
        public void OnRegisterCaps(Scene scene, UUID agentID, Caps caps)
        {
            m_log.DebugFormat(
                "[FreeSwitchVoice]: OnRegisterCaps() called with agentID {0} caps {1} in scene {2}", 
                agentID, caps, scene.RegionInfo.RegionName);
            string capsBase = "/CAPS/" + caps.CapsObjectPath;
            caps.RegisterHandler(
                "ProvisionVoiceAccountRequest",
                new RestStreamHandler(
                    "POST",
                    capsBase + m_provisionVoiceAccountRequestPath,
                    (request, path, param, httpRequest, httpResponse)
                        => ProvisionVoiceAccountRequest(scene, request, path, param, agentID, caps),
                    "ProvisionVoiceAccountRequest",
                    agentID.ToString()));
            caps.RegisterHandler(
                "ParcelVoiceInfoRequest",
                new RestStreamHandler(
                    "POST",
                    capsBase + m_parcelVoiceInfoRequestPath,
                        (request, path, param, httpRequest, httpResponse)
                            => ParcelVoiceInfoRequest(scene, request, path, param, agentID, caps),
                    "ParcelVoiceInfoRequest",
                    agentID.ToString()));
            caps.RegisterHandler(
                "ChatSessionRequest",
                new RestStreamHandler(
                    "POST",
                    capsBase + m_chatSessionRequestPath,
                            (request, path, param, httpRequest, httpResponse)
                                => ChatSessionRequest(scene, request, path, param, agentID, caps),
                    "ChatSessionRequest",
                    agentID.ToString()));
        }
        /// <summary>
        /// Callback for a client request for Voice Account Details
        /// </summary>
        /// <param name="scene">current scene object of the client</param>
        /// <param name="request"></param>
        /// <param name="path"></param>
        /// <param name="param"></param>
        /// <param name="agentID"></param>
        /// <param name="caps"></param>
        /// <returns></returns>
        public string ProvisionVoiceAccountRequest(Scene scene, string request, string path, string param,
                                                   UUID agentID, Caps caps)
        {
            m_log.DebugFormat(
                "[FreeSwitchVoice][PROVISIONVOICE]: ProvisionVoiceAccountRequest() request: {0}, path: {1}, param: {2}", request, path, param);
            
            ScenePresence avatar = scene.GetScenePresence(agentID);
            if (avatar == null)
            {
                System.Threading.Thread.Sleep(2000);
                avatar = scene.GetScenePresence(agentID);
                if (avatar == null)
                    return "<llsd>undef</llsd>";
            }
            string avatarName = avatar.Name;
            try
            {
                //XmlElement    resp;
                string agentname = "x" + Convert.ToBase64String(agentID.GetBytes());
                string password  = "1234";//temp hack//new UUID(Guid.NewGuid()).ToString().Replace('-','Z').Substring(0,16);
                // XXX: we need to cache the voice credentials, as
                // FreeSwitch is later going to come and ask us for
                // those
                agentname = agentname.Replace('+', '-').Replace('/', '_');
                lock (m_UUIDName)
                {
                    if (m_UUIDName.ContainsKey(agentname))
                    {
                        m_UUIDName[agentname] = avatarName;
                    }
                    else
                    {
                        m_UUIDName.Add(agentname, avatarName);
                    }
                }
                // LLSDVoiceAccountResponse voiceAccountResponse =
               //     new LLSDVoiceAccountResponse(agentname, password, m_freeSwitchRealm, "http://etsvc02.hursley.ibm.com/api");
               LLSDVoiceAccountResponse voiceAccountResponse =
                   new LLSDVoiceAccountResponse(agentname, password, m_freeSwitchRealm,
                                                String.Format("http://{0}:{1}{2}/", m_openSimWellKnownHTTPAddress,
                                                              m_freeSwitchServicePort, m_freeSwitchAPIPrefix));
                string r = LLSDHelpers.SerialiseLLSDReply(voiceAccountResponse);
//                m_log.DebugFormat("[FreeSwitchVoice][PROVISIONVOICE]: avatar \"{0}\": {1}", avatarName, r);
                return r;
            }
            catch (Exception e)
            {
                m_log.ErrorFormat("[FreeSwitchVoice][PROVISIONVOICE]: avatar \"{0}\": {1}, retry later", avatarName, e.Message);
                m_log.DebugFormat("[FreeSwitchVoice][PROVISIONVOICE]: avatar \"{0}\": {1} failed", avatarName, e.ToString());
                return "<llsd>undef</llsd>";
            }
        }
        /// <summary>
        /// Callback for a client request for ParcelVoiceInfo
        /// </summary>
        /// <param name="scene">current scene object of the client</param>
        /// <param name="request"></param>
        /// <param name="path"></param>
        /// <param name="param"></param>
        /// <param name="agentID"></param>
        /// <param name="caps"></param>
        /// <returns></returns>
        public string ParcelVoiceInfoRequest(Scene scene, string request, string path, string param,
                                             UUID agentID, Caps caps)
        {
            m_log.DebugFormat(
                "[FreeSwitchVoice][PARCELVOICE]: ParcelVoiceInfoRequest() on {0} for {1}", 
                scene.RegionInfo.RegionName, agentID);
            
            ScenePresence avatar = scene.GetScenePresence(agentID);
            string avatarName = avatar.Name;
            // - check whether we have a region channel in our cache
            // - if not:
            //       create it and cache it
            // - send it to the client
            // - send channel_uri: as "sip:regionID@m_sipDomain"
            try
            {
                LLSDParcelVoiceInfoResponse parcelVoiceInfo;
                string channelUri;
                if (null == scene.LandChannel)
                    throw new Exception(String.Format("region \"{0}\": avatar \"{1}\": land data not yet available",
                                                      scene.RegionInfo.RegionName, avatarName));
                // get channel_uri: check first whether estate
                // settings allow voice, then whether parcel allows
                // voice, if all do retrieve or obtain the parcel
                // voice channel
                LandData land = scene.GetLandData(avatar.AbsolutePosition);
                //m_log.DebugFormat("[FreeSwitchVoice][PARCELVOICE]: region \"{0}\": Parcel \"{1}\" ({2}): avatar \"{3}\": request: {4}, path: {5}, param: {6}",
                //                  scene.RegionInfo.RegionName, land.Name, land.LocalID, avatarName, request, path, param);
                // TODO: EstateSettings don't seem to get propagated...
                // if (!scene.RegionInfo.EstateSettings.AllowVoice)
                // {
                //     m_log.DebugFormat("[FreeSwitchVoice][PARCELVOICE]: region \"{0}\": voice not enabled in estate settings",
                //                       scene.RegionInfo.RegionName);
                //     channel_uri = String.Empty;
                // }
                // else
                if ((land.Flags & (uint)ParcelFlags.AllowVoiceChat) == 0)
                {
//                    m_log.DebugFormat("[FreeSwitchVoice][PARCELVOICE]: region \"{0}\": Parcel \"{1}\" ({2}): avatar \"{3}\": voice not enabled for parcel",
//                                      scene.RegionInfo.RegionName, land.Name, land.LocalID, avatarName);
                    channelUri = String.Empty;
                }
                else
                {


Answer:                     channelUri = ChannelUri(scene, land);