/// <summary>
 /// Default constructor.
 /// </summary>
 /// <param name="stack">Reference to SIP stack.</param>
 /// <param name="flow">SIP data flow.</param>
 /// <param name="request">Recieved request.</param>
 /// <param name="transaction">SIP server transaction which must be used to send response back to request maker.</param>
 internal SIP_RequestReceivedEventArgs(SIP_Stack stack, SIP_Flow flow, SIP_Request request, SIP_ServerTransaction transaction)
 {
     m_pStack       = stack;
     m_pFlow        = flow;
     m_pRequest     = request;
     m_pTransaction = transaction;
 }
        /// <summary>
        /// Sends specified request to the specified data flow.
        /// </summary>
        /// <param name="flow">SIP data flow.</param>
        /// <param name="request">SIP request to send.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null reference.</exception>
        private void SendToFlow(SIP_Flow flow, SIP_Request request)
        {
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            #region Contact (RFC 3261 8.1.1.8)

            /*
             *  The Contact header field provides a SIP or SIPS URI that can be used
             *  to contact that specific instance of the UA for subsequent requests.
             *  The Contact header field MUST be present and contain exactly one SIP
             *  or SIPS URI in any request that can result in the establishment of a
             *  dialog.  For the methods defined in this specification, that includes
             *  only the INVITE request.  For these requests, the scope of the
             *  Contact is global.  That is, the Contact header field value contains
             *  the URI at which the UA would like to receive requests, and this URI
             *  MUST be valid even if used in subsequent requests outside of any
             *  dialogs.
             *
             *  If the Request-URI or top Route header field value contains a SIPS
             *  URI, the Contact header field MUST contain a SIPS URI as well.
             */

            SIP_t_ContactParam contact = request.Contact.GetTopMostValue();

            // Add contact header If request-Method can establish dialog and contact header not present.
            if (SIP_Utils.MethodCanEstablishDialog(request.RequestLine.Method) && contact == null)
            {
                SIP_Uri from = (SIP_Uri)request.From.Address.Uri;

                request.Contact.Add((flow.IsSecure ? "sips:" : "sip:") + from.User + "@" + flow.LocalPublicEP.ToString());

                // REMOVE ME: 22.10.2010
                //request.Contact.Add((flow.IsSecure ? "sips:" : "sip:" ) + from.User + "@" + m_pStack.TransportLayer.GetContactHost(flow).ToString());
            }
            // If contact SIP URI and host = auto-allocate, allocate it as needed.
            else if (contact != null && contact.Address.Uri is SIP_Uri && ((SIP_Uri)contact.Address.Uri).Host == "auto-allocate")
            {
                ((SIP_Uri)contact.Address.Uri).Host = flow.LocalPublicEP.ToString();

                // REMOVE ME: 22.10.2010
                //((SIP_Uri)contact.Address.Uri).Host =  m_pStack.TransportLayer.GetContactHost(flow).ToString();
            }

            #endregion

            m_pTransaction = m_pStack.TransactionLayer.CreateClientTransaction(flow, request, true);
            m_pTransaction.ResponseReceived += new EventHandler <SIP_ResponseReceivedEventArgs>(ClientTransaction_ResponseReceived);
            m_pTransaction.TimedOut         += new EventHandler(ClientTransaction_TimedOut);
            m_pTransaction.TransportError   += new EventHandler <ExceptionEventArgs>(ClientTransaction_TransportError);

            // Start transaction processing.
            m_pTransaction.Start();
        }
Beispiel #3
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        /// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="stack">Owner SIP stack.</param>
        /// <param name="flow">Transaction data flow.</param>
        /// <param name="request">SIP request that transaction will handle.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stack</b>,<b>flow</b> or <b>request</b> is null reference.</exception>
        public SIP_Transaction(SIP_Stack stack, SIP_Flow flow, SIP_Request request)
        {
            if (stack == null)
            {
                throw new ArgumentNullException("stack");
            }
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            m_pStack     = stack;
            m_pFlow      = flow;
            m_pRequest   = request;
            m_Method     = request.RequestLine.Method;
            m_CreateTime = DateTime.Now;
            m_pResponses = new List <SIP_Response>();

            // Validate Via:
            SIP_t_ViaParm via = request.Via.GetTopMostValue();

            if (via == null)
            {
                throw new ArgumentException("Via: header is missing !");
            }
            if (via.Branch == null)
            {
                throw new ArgumentException("Via: header 'branch' parameter is missing !");
            }

            m_ID = via.Branch;

            if (this is SIP_ServerTransaction)
            {
                /*
                 *  We use branch and sent-by as indexing key for transaction, the only special what we need to
                 *  do is to handle CANCEL, because it has same branch as transaction to be canceled.
                 *  For avoiding key collision, we add branch + '-' + 'sent-by' + CANCEL for cancel index key.
                 *  ACK has also same branch, but we won't do transaction for ACK, so it isn't problem.
                 */
                string key = request.Via.GetTopMostValue().Branch + '-' + request.Via.GetTopMostValue().SentBy;
                if (request.RequestLine.Method == SIP_Methods.CANCEL)
                {
                    key += "-CANCEL";
                }
                m_Key = key;
            }
            else
            {
                m_Key = m_ID + "-" + request.RequestLine.Method;
            }
        }
        /// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="stack">Owner SIP stack.</param>
        /// <param name="flow">SIP data flow which received request.</param>
        /// <param name="request">SIP request that transaction will handle.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stack</b>,<b>flow</b> or <b>request</b> is null reference.</exception>
        /// <exception cref="ArgumentException">Is raised when any of the arguments has invalid value.</exception>
        public SIP_ServerTransaction(SIP_Stack stack, SIP_Flow flow, SIP_Request request) : base(stack, flow, request)
        {
            // Log
            if (this.Stack.Logger != null)
            {
                this.Stack.Logger.AddText(this.ID, "Transaction [branch='" + this.ID + "';method='" + this.Method + "';IsServer=true] created.");
            }

            Start();
        }
Beispiel #5
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        /// <summary>
        /// Cleans up any resources being used.
        /// </summary>
        public virtual void Dispose()
        {
            SetState(SIP_TransactionState.Disposed);
            OnDisposed();

            m_pStack   = null;
            m_pFlow    = null;
            m_pRequest = null;

            this.StateChanged   = null;
            this.Disposed       = null;
            this.TimedOut       = null;
            this.TransportError = null;
        }
        /// <summary>
        /// Creates new client transaction.
        /// </summary>
        /// <param name="flow">SIP data flow which is used to send request.</param>
        /// <param name="request">SIP request that transaction will handle.</param>
        /// <param name="addVia">If true, transaction will add <b>Via:</b> header, otherwise it's user responsibility.</param>
        /// <exception cref="ObjectDisposedException">Is raised when this class is Disposed and this method is accessed.</exception>
        /// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null reference.</exception>
        /// <returns>Returns created transaction.</returns>
        public SIP_ClientTransaction CreateClientTransaction(SIP_Flow flow, SIP_Request request, bool addVia)
        {
            if (m_IsDisposed)
            {
                throw new ObjectDisposedException(this.GetType().Name);
            }
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            // Add Via:
            if (addVia)
            {
                SIP_t_ViaParm via = new SIP_t_ViaParm();
                via.ProtocolName      = "SIP";
                via.ProtocolVersion   = "2.0";
                via.ProtocolTransport = flow.Transport;
                via.SentBy            = new HostEndPoint("transport_layer_will_replace_it", -1);
                via.Branch            = SIP_t_ViaParm.CreateBranch();
                via.RPort             = 0;
                request.Via.AddToTop(via.ToStringValue());
            }

            lock (m_pClientTransactions){
                SIP_ClientTransaction transaction = new SIP_ClientTransaction(m_pStack, flow, request);
                m_pClientTransactions.Add(transaction.Key, transaction);
                transaction.StateChanged += new EventHandler(delegate(object s, EventArgs e){
                    if (transaction.State == SIP_TransactionState.Terminated)
                    {
                        lock (m_pClientTransactions){
                            m_pClientTransactions.Remove(transaction.Key);
                        }
                    }
                });

                SIP_Dialog dialog = MatchDialog(request);
                if (dialog != null)
                {
                    dialog.AddTransaction(transaction);
                }

                return(transaction);
            }
        }
        /// <summary>
        /// Default constructor.
        /// </summary>
        /// <param name="stack">Owner stack.</param>
        /// <param name="request">SIP request.</param>
        /// <param name="flow">Active data flow what to try before RFC 3261 [4](RFC 3263) methods to use to send request.
        /// This value can be null.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stack</b> or <b>request</b> is null.</exception>
        internal SIP_RequestSender(SIP_Stack stack, SIP_Request request, SIP_Flow flow)
        {
            if (stack == null)
            {
                throw new ArgumentNullException("stack");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            m_pStack   = stack;
            m_pRequest = request;
            m_pFlow    = flow;

            m_pCredentials = new List <NetworkCredential>();
            m_pHops        = new Queue <SIP_Hop>();
        }
        /// <summary>
        /// Ensures that specified request has matching server transaction. If server transaction doesn't exist,
        /// it will be created, otherwise existing transaction will be returned.
        /// </summary>
        /// <param name="flow">SIP data flow which is used to receive request.</param>
        /// <param name="request">SIP request.</param>
        /// <returns>Returns matching transaction.</returns>
        /// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null.</exception>
        /// <exception cref="InvalidOperationException">Is raised when request.Method is ACK request.</exception>
        public SIP_ServerTransaction EnsureServerTransaction(SIP_Flow flow, SIP_Request request)
        {
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }
            if (request.RequestLine.Method == SIP_Methods.ACK)
            {
                throw new InvalidOperationException("ACK request is transaction less request, can't create transaction for it.");
            }

            /*
             *  We use branch and sent-by as indexing key for transaction, the only special what we need to
             *  do is to handle CANCEL, because it has same branch as transaction to be canceled.
             *  For avoiding key collision, we add branch + '-' + 'sent-by' + CANCEL for cancel index key.
             *  ACK has also same branch, but we won't do transaction for ACK, so it isn't problem.
             */
            string key = request.Via.GetTopMostValue().Branch + '-' + request.Via.GetTopMostValue().SentBy;

            if (request.RequestLine.Method == SIP_Methods.CANCEL)
            {
                key += "-CANCEL";
            }

            lock (m_pServerTransactions){
                SIP_ServerTransaction retVal = null;
                m_pServerTransactions.TryGetValue(key, out retVal);
                // We don't have transaction, create it.
                if (retVal == null)
                {
                    retVal = CreateServerTransaction(flow, request);
                }

                return(retVal);
            }
        }
Beispiel #9
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        /// <summary>
        /// Cleans up any resources being used.
        /// </summary>
        public virtual void Dispose()
        {
            lock (m_pLock){
                if (this.State == SIP_DialogState.Disposed)
                {
                    return;
                }

                SetState(SIP_DialogState.Disposed, true);

                this.RequestReceived = null;
                m_pStack             = null;
                m_CallID             = null;
                m_LocalTag           = null;
                m_RemoteTag          = null;
                m_pLocalUri          = null;
                m_pRemoteUri         = null;
                m_pLocalContact      = null;
                m_pRemoteTarget      = null;
                m_pRouteSet          = null;
                m_pFlow = null;
            }
        }
        /// <summary>
        /// Creates new SIP server transaction for specified request.
        /// </summary>
        /// <param name="flow">SIP data flow which is used to receive request.</param>
        /// <param name="request">SIP request.</param>
        /// <returns>Returns added server transaction.</returns>
        /// <exception cref="ObjectDisposedException">Is raised when this class is Disposed and this method is accessed.</exception>
        /// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null reference.</exception>
        public SIP_ServerTransaction CreateServerTransaction(SIP_Flow flow, SIP_Request request)
        {
            if (m_IsDisposed)
            {
                throw new ObjectDisposedException(this.GetType().Name);
            }
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            lock (m_pServerTransactions){
                SIP_ServerTransaction transaction = new SIP_ServerTransaction(m_pStack, flow, request);
                m_pServerTransactions.Add(transaction.Key, transaction);
                transaction.StateChanged += new EventHandler(delegate(object s, EventArgs e){
                    if (transaction.State == SIP_TransactionState.Terminated)
                    {
                        lock (m_pClientTransactions){
                            m_pServerTransactions.Remove(transaction.Key);
                        }
                    }
                });

                SIP_Dialog dialog = MatchDialog(request);
                if (dialog != null)
                {
                    dialog.AddTransaction(transaction);
                }

                return(transaction);
            }
        }
        /// <summary>
        /// Processes specified request through this transaction.
        /// </summary>
        /// <param name="flow">SIP data flow.</param>
        /// <param name="request">SIP request.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null reference.</exception>
        internal void ProcessRequest(SIP_Flow flow, SIP_Request request)
        {
            if (flow == null)
            {
                throw new ArgumentNullException("flow");
            }
            if (request == null)
            {
                throw new ArgumentNullException("request");
            }

            lock (this.SyncRoot){
                if (this.State == SIP_TransactionState.Disposed)
                {
                    return;
                }

                try{
                    // Log
                    if (this.Stack.Logger != null)
                    {
                        byte[] requestData = request.ToByteData();

                        this.Stack.Logger.AddRead(
                            Guid.NewGuid().ToString(),
                            null,
                            0,
                            "Request [transactionID='" + this.ID + "'; method='" + request.RequestLine.Method + "'; cseq='" + request.CSeq.SequenceNumber + "'; " +
                            "transport='" + flow.Transport + "'; size='" + requestData.Length + "'; received '" + flow.LocalEP + "' <- '" + flow.RemoteEP + "'.",
                            flow.LocalEP,
                            flow.RemoteEP,
                            requestData
                            );
                    }

                    #region INVITE

                    if (this.Method == SIP_Methods.INVITE)
                    {
                        #region INVITE

                        if (request.RequestLine.Method == SIP_Methods.INVITE)
                        {
                            if (this.State == SIP_TransactionState.Proceeding)
                            {
                                /* RFC 3261 17.2.1.
                                 *  If a request retransmission is received while in the "Proceeding" state, the most recent provisional
                                 *  response that was received from the TU MUST be passed to the transport layer for retransmission.
                                 */
                                SIP_Response response = this.LastProvisionalResponse;
                                if (response != null)
                                {
                                    this.Stack.TransportLayer.SendResponse(this, response);
                                }
                            }
                            else if (this.State == SIP_TransactionState.Completed)
                            {
                                /* RFC 3261 17.2.1.
                                 *  While in the "Completed" state, if a request retransmission is received, the server SHOULD
                                 *  pass the response to the transport for retransmission.
                                 */
                                this.Stack.TransportLayer.SendResponse(this, this.FinalResponse);
                            }
                        }

                        #endregion

                        #region ACK

                        else if (request.RequestLine.Method == SIP_Methods.ACK)
                        {
                            #region Accepeted

                            if (this.State == SIP_TransactionState.Accpeted)
                            {
                            }

                            #endregion

                            #region Completed

                            else if (this.State == SIP_TransactionState.Completed)
                            {
                                /* RFC 3261 17.2.1
                                 *  If an ACK is received while the server transaction is in the "Completed" state, the server transaction
                                 *  MUST transition to the "Confirmed" state.  As Timer G is ignored in this state, any retransmissions of the
                                 *  response will cease.
                                 *
                                 *  When this state is entered, timer I is set to fire in T4 seconds for unreliable transports,
                                 *  and zero seconds for reliable transports.
                                 */

                                SetState(SIP_TransactionState.Confirmed);

                                // Stop timers G,H
                                if (m_pTimerG != null)
                                {
                                    m_pTimerG.Dispose();
                                    m_pTimerG = null;

                                    // Log
                                    if (this.Stack.Logger != null)
                                    {
                                        this.Stack.Logger.AddText(this.ID, "Transaction [branch='" + this.ID + "';method='" + this.Method + "';IsServer=true] timer G(INVITE response(3xx - 6xx) retransmission) stopped.");
                                    }
                                }
                                if (m_pTimerH != null)
                                {
                                    m_pTimerH.Dispose();
                                    m_pTimerH = null;

                                    // Log
                                    if (this.Stack.Logger != null)
                                    {
                                        this.Stack.Logger.AddText(this.ID, "Transaction [branch='" + this.ID + "';method='" + this.Method + "';IsServer=true] timer H(INVITE ACK wait) stopped.");
                                    }
                                }

                                // Start timer I.
                                m_pTimerI          = new TimerEx((flow.IsReliable ? 0 : SIP_TimerConstants.T4), false);
                                m_pTimerI.Elapsed += new System.Timers.ElapsedEventHandler(m_pTimerI_Elapsed);
                                // Log
                                if (this.Stack.Logger != null)
                                {
                                    this.Stack.Logger.AddText(this.ID, "Transaction [branch='" + this.ID + "';method='" + this.Method + "';IsServer=true] timer I(INVITE ACK retransission wait) started, will trigger after " + m_pTimerI.Interval + ".");
                                }
                                m_pTimerI.Enabled = true;
                            }

                            #endregion
                        }

                        #endregion
                    }

                    #endregion

                    #region Non-INVITE

                    else
                    {
                        // Non-INVITE transaction may have only request retransmission requests.
                        if (this.Method == request.RequestLine.Method)
                        {
                            if (this.State == SIP_TransactionState.Proceeding)
                            {
                                /* RFC 3261 17.2.2.
                                 *  If a retransmission of the request is received while in the "Proceeding" state, the most
                                 *  recently sent provisional response MUST be passed to the transport layer for retransmission.
                                 */
                                this.Stack.TransportLayer.SendResponse(this, this.LastProvisionalResponse);
                            }
                            else if (this.State == SIP_TransactionState.Completed)
                            {
                                /* RFC 3261 17.2.2.
                                 *  While in the "Completed" state, the server transaction MUST pass the final response to the transport
                                 *  layer for retransmission whenever a retransmission of the request is received.
                                 */
                                this.Stack.TransportLayer.SendResponse(this, this.FinalResponse);
                            }
                        }
                    }

                    #endregion
                }
                catch (SIP_TransportException x) {
                    // Log
                    if (this.Stack.Logger != null)
                    {
                        this.Stack.Logger.AddText(this.ID, "Transaction [branch='" + this.ID + "';method='" + this.Method + "';IsServer=true] transport exception: " + x.Message);
                    }

                    OnTransportError(x);
                }
            }
        }
 /// <summary>
 /// Default constructor.
 /// </summary>
 /// <param name="stack">Reference to SIP stack.</param>
 /// <param name="flow">SIP data flow.</param>
 /// <param name="request">Recieved request.</param>
 internal SIP_RequestReceivedEventArgs(SIP_Stack stack, SIP_Flow flow, SIP_Request request) : this(stack, flow, request, null)
 {
 }
Beispiel #13
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        /// <summary>
        /// Initializes dialog.
        /// </summary>
        /// <param name="stack">Owner stack.</param>
        /// <param name="transaction">Owner transaction.</param>
        /// <param name="response">SIP response what caused dialog creation.</param>
        /// <exception cref="ArgumentNullException">Is raised when <b>stack</b>,<b>transaction</b> or <b>response</b>.</exception>
        internal protected virtual void Init(SIP_Stack stack, SIP_Transaction transaction, SIP_Response response)
        {
            if (stack == null)
            {
                throw new ArgumentNullException("stack");
            }
            if (transaction == null)
            {
                throw new ArgumentNullException("transaction");
            }
            if (response == null)
            {
                throw new ArgumentNullException("response");
            }

            m_pStack = stack;

            #region UAS

            /* RFC 3261 12.1.1.
             *  The UAS then constructs the state of the dialog.  This state MUST be
             *  maintained for the duration of the dialog.
             *
             *  If the request arrived over TLS, and the Request-URI contained a SIPS
             *  URI, the "secure" flag is set to TRUE.
             *
             *  The route set MUST be set to the list of URIs in the Record-Route
             *  header field from the request, taken in order and preserving all URI
             *  parameters.  If no Record-Route header field is present in the
             *  request, the route set MUST be set to the empty set.  This route set,
             *  even if empty, overrides any pre-existing route set for future
             *  requests in this dialog.  The remote target MUST be set to the URI
             *  from the Contact header field of the request.
             *
             *  The remote sequence number MUST be set to the value of the sequence
             *  number in the CSeq header field of the request.  The local sequence
             *  number MUST be empty.  The call identifier component of the dialog ID
             *  MUST be set to the value of the Call-ID in the request.  The local
             *  tag component of the dialog ID MUST be set to the tag in the To field
             *  in the response to the request (which always includes a tag), and the
             *  remote tag component of the dialog ID MUST be set to the tag from the
             *  From field in the request.  A UAS MUST be prepared to receive a
             *  request without a tag in the From field, in which case the tag is
             *  considered to have a value of null.
             *
             *      This is to maintain backwards compatibility with RFC 2543, which
             *      did not mandate From tags.
             *
             *  The remote URI MUST be set to the URI in the From field, and the
             *  local URI MUST be set to the URI in the To field.
             */

            if (transaction is SIP_ServerTransaction)
            {
                m_IsSecure      = ((SIP_Uri)transaction.Request.RequestLine.Uri).IsSecure;
                m_pRouteSet     = (SIP_t_AddressParam[])Net_Utils.ReverseArray(transaction.Request.RecordRoute.GetAllValues());
                m_pRemoteTarget = (SIP_Uri)transaction.Request.Contact.GetTopMostValue().Address.Uri;
                m_RemoteSeqNo   = transaction.Request.CSeq.SequenceNumber;
                m_LocalSeqNo    = 0;
                m_CallID        = transaction.Request.CallID;
                m_LocalTag      = response.To.Tag;
                m_RemoteTag     = transaction.Request.From.Tag;
                m_pRemoteUri    = transaction.Request.From.Address.Uri;
                m_pLocalUri     = transaction.Request.To.Address.Uri;
                m_pLocalContact = (SIP_Uri)response.Contact.GetTopMostValue().Address.Uri;

                List <string> allow = new List <string>();
                foreach (SIP_t_Method m in response.Allow.GetAllValues())
                {
                    allow.Add(m.Method);
                }
                m_pRemoteAllow = allow.ToArray();

                List <string> supported = new List <string>();
                foreach (SIP_t_OptionTag s in response.Supported.GetAllValues())
                {
                    supported.Add(s.OptionTag);
                }
                m_pRemoteSupported = supported.ToArray();
            }

            #endregion

            #region UAC

            /* RFC 3261 12.1.2.
             *  When a UAC receives a response that establishes a dialog, it
             *  constructs the state of the dialog.  This state MUST be maintained
             *  for the duration of the dialog.
             *
             *  If the request was sent over TLS, and the Request-URI contained a
             *  SIPS URI, the "secure" flag is set to TRUE.
             *
             *  The route set MUST be set to the list of URIs in the Record-Route
             *  header field from the response, taken in reverse order and preserving
             *  all URI parameters.  If no Record-Route header field is present in
             *  the response, the route set MUST be set to the empty set.  This route
             *  set, even if empty, overrides any pre-existing route set for future
             *  requests in this dialog.  The remote target MUST be set to the URI
             *  from the Contact header field of the response.
             *
             *  The local sequence number MUST be set to the value of the sequence
             *  number in the CSeq header field of the request.  The remote sequence
             *  number MUST be empty (it is established when the remote UA sends a
             *  request within the dialog).  The call identifier component of the
             *  dialog ID MUST be set to the value of the Call-ID in the request.
             *  The local tag component of the dialog ID MUST be set to the tag in
             *  the From field in the request, and the remote tag component of the
             *  dialog ID MUST be set to the tag in the To field of the response.  A
             *  UAC MUST be prepared to receive a response without a tag in the To
             *  field, in which case the tag is considered to have a value of null.
             *
             *      This is to maintain backwards compatibility with RFC 2543, which
             *      did not mandate To tags.
             *
             *  The remote URI MUST be set to the URI in the To field, and the local
             *  URI MUST be set to the URI in the From field.
             */

            else
            {
                // TODO: Validate request or client transaction must do it ?

                m_IsSecure      = ((SIP_Uri)transaction.Request.RequestLine.Uri).IsSecure;
                m_pRouteSet     = (SIP_t_AddressParam[])Net_Utils.ReverseArray(response.RecordRoute.GetAllValues());
                m_pRemoteTarget = (SIP_Uri)response.Contact.GetTopMostValue().Address.Uri;
                m_LocalSeqNo    = transaction.Request.CSeq.SequenceNumber;
                m_RemoteSeqNo   = 0;
                m_CallID        = transaction.Request.CallID;
                m_LocalTag      = transaction.Request.From.Tag;
                m_RemoteTag     = response.To.Tag;
                m_pRemoteUri    = transaction.Request.To.Address.Uri;
                m_pLocalUri     = transaction.Request.From.Address.Uri;
                m_pLocalContact = (SIP_Uri)transaction.Request.Contact.GetTopMostValue().Address.Uri;

                List <string> allow = new List <string>();
                foreach (SIP_t_Method m in response.Allow.GetAllValues())
                {
                    allow.Add(m.Method);
                }
                m_pRemoteAllow = allow.ToArray();

                List <string> supported = new List <string>();
                foreach (SIP_t_OptionTag s in response.Supported.GetAllValues())
                {
                    supported.Add(s.OptionTag);
                }
                m_pRemoteSupported = supported.ToArray();
            }

            #endregion

            m_pFlow = transaction.Flow;
            AddTransaction(transaction);
        }
        /// <summary>
        /// This method is called when REGISTER has finished.
        /// </summary>
        /// <param name="sender">Sender.</param>
        /// <param name="e">Event data.</param>
        private void m_pRegisterSender_ResponseReceived(object sender, SIP_ResponseReceivedEventArgs e)
        {
            m_pFlow = e.ClientTransaction.Flow;

            if (e.Response.StatusCodeType == SIP_StatusCodeType.Provisional)
            {
                return;
            }
            else if (e.Response.StatusCodeType == SIP_StatusCodeType.Success)
            {
                m_pContacts.Clear();
                foreach (SIP_t_ContactParam c in e.Response.Contact.GetAllValues())
                {
                    m_pContacts.Add(c.Address.Uri);
                }

                SetState(SIP_UA_RegistrationState.Registered);

                OnRegistered();

                m_pFlow.SendKeepAlives = true;
            }
            else
            {
                SetState(SIP_UA_RegistrationState.Error);

                OnError(e);
            }

            // REMOVE ME:
            if (this.AutoFixContact && (m_pContact is SIP_Uri))
            {
                // If Via: received or rport paramter won't match to our sent-by, use received and rport to construct new contact value.

                SIP_Uri       cContact   = ((SIP_Uri)m_pContact);
                IPAddress     cContactIP = Net_Utils.IsIPAddress(cContact.Host) ? IPAddress.Parse(cContact.Host) : null;
                SIP_t_ViaParm via        = e.Response.Via.GetTopMostValue();
                if (via != null && cContactIP != null)
                {
                    IPEndPoint ep = new IPEndPoint(via.Received != null ? via.Received : cContactIP, via.RPort > 0 ? via.RPort : cContact.Port);
                    if (!cContactIP.Equals(ep.Address) || cContact.Port != via.RPort)
                    {
                        // Unregister old contact.
                        BeginUnregister(false);

                        // Fix contact.
                        cContact.Host = ep.Address.ToString();
                        cContact.Port = ep.Port;

                        m_pRegisterSender.Dispose();
                        m_pRegisterSender = null;

                        BeginRegister(m_AutoRefresh);

                        return;
                    }
                }
            }

            if (m_AutoRefresh)
            {
                // Set registration refresh timer.
                m_pTimer.Enabled = true;
            }

            m_pRegisterSender.Dispose();
            m_pRegisterSender = null;
        }
        /// <summary>
        /// Is called when client transactions receives response.
        /// </summary>
        /// <param name="sender">Sender.</param>
        /// <param name="e">Event data.</param>
        private void ClientTransaction_ResponseReceived(object sender, SIP_ResponseReceivedEventArgs e)
        {
            lock (m_pLock){
                m_pFlow = e.ClientTransaction.Request.Flow;

                if (e.Response.StatusCode == 401 || e.Response.StatusCode == 407)
                {
                    // Check if authentication failed(We sent authorization data and it's challenged again,
                    // probably user name or password inccorect)
                    bool hasFailedAuthorization = false;
                    foreach (SIP_t_Challenge challange in e.Response.WWWAuthenticate.GetAllValues())
                    {
                        foreach (SIP_t_Credentials credentials in m_pTransaction.Request.Authorization.GetAllValues())
                        {
                            if (new Auth_HttpDigest(challange.AuthData, "").Realm == new Auth_HttpDigest(credentials.AuthData, "").Realm)
                            {
                                hasFailedAuthorization = true;
                                break;
                            }
                        }
                    }
                    foreach (SIP_t_Challenge challange in e.Response.ProxyAuthenticate.GetAllValues())
                    {
                        foreach (SIP_t_Credentials credentials in m_pTransaction.Request.ProxyAuthorization.GetAllValues())
                        {
                            if (new Auth_HttpDigest(challange.AuthData, "").Realm == new Auth_HttpDigest(credentials.AuthData, "").Realm)
                            {
                                hasFailedAuthorization = true;
                                break;
                            }
                        }
                    }

                    // Authorization failed, pass response to UA.
                    if (hasFailedAuthorization)
                    {
                        OnResponseReceived(e.Response);
                    }
                    // Try to authorize challanges.
                    else
                    {
                        SIP_Request request = m_pRequest.Copy();

                        /* RFC 3261 22.2.
                         *  When a UAC resubmits a request with its credentials after receiving a
                         *  401 (Unauthorized) or 407 (Proxy Authentication Required) response,
                         *  it MUST increment the CSeq header field value as it would normally
                         *  when sending an updated request.
                         */
                        request.CSeq = new SIP_t_CSeq(m_pStack.ConsumeCSeq(), request.CSeq.RequestMethod);

                        // All challanges authorized, resend request.
                        if (Authorize(request, e.Response, this.Credentials.ToArray()))
                        {
                            SIP_Flow flow = m_pTransaction.Flow;
                            CleanUpActiveTransaction();
                            SendToFlow(flow, request);
                        }
                        // We don't have credentials for one or more challenges.
                        else
                        {
                            OnResponseReceived(e.Response);
                        }
                    }
                }
                else
                {
                    OnResponseReceived(e.Response);
                    if (e.Response.StatusCodeType != SIP_StatusCodeType.Provisional)
                    {
                        OnCompleted();
                    }
                }
            }
        }