/// <summary> /// Starts the client transaction. /// </summary> public void Start() { SipCSeqValue vCSeq; // Add a CSeq header to the request if necessary and intialize the // transaction's local sequence number. vCSeq = request.GetHeader <SipCSeqValue>(SipHeader.CSeq); if (vCSeq == null) { request.AddHeader(SipHeader.CSeq, new SipCSeqValue(SipHelper.GenCSeq(), request.MethodText)); } // Add Max-Forwards if necessary. if (request.GetHeaderText(SipHeader.MaxForwards) == null) { request.AddHeader(SipHeader.MaxForwards, SipHelper.MaxForwards); } // Start the transaction using (TimedLock.Lock(agent)) { SetState(request.Method == SipMethod.Invite ? SipTransactionState.InviteCalling : SipTransactionState.Trying); transport.Send(remoteEP, request); } }
/// <summary> /// Creates the proper ACK request based on the original INVITE request sent /// to the server and the 2xx response received. /// </summary> /// <param name="inviteRequest">The INVITE <see cref="SipRequest" /> sent to the server.</param> /// <param name="response">The 2xx <see cref="SipResponse" /> received from the server.</param> /// <returns>The created ACK <see cref="SipRequest" />.</returns> private SipRequest CreateAckRequest(SipRequest inviteRequest, SipResponse response) { SipRequest ackRequest; SipHeader callID; SipHeader to; SipHeader from; SipHeader via; SipHeader contact; SipHeader route; SipCSeqValue vCSeq; if (inviteRequest.Method != SipMethod.Invite) { throw new ArgumentException("INVITE request expected.", "inviteRequest"); } if (response.IsProvisional) { throw new ArgumentException("Non-provisional response expected.", "response"); } ackRequest = new SipRequest(SipMethod.Ack, inviteRequest.Uri, null); callID = inviteRequest[SipHeader.CallID]; to = response[SipHeader.To]; from = inviteRequest[SipHeader.From]; via = inviteRequest[SipHeader.Via]; contact = inviteRequest[SipHeader.Contact]; route = inviteRequest[SipHeader.Route]; if (callID == null) { throw new SipException("INVITE request is missing header: [Call-ID]"); } if (to == null) { throw new SipException("INVITE response is missing header: [To]"); } if (from == null) { throw new SipException("INVITE request is missing header: [From]"); } if (contact == null) { throw new SipException("INVITE request is missing header: [Contact]"); } if (via == null) { throw new SipException("INVITE request is missing header: [Via]"); } vCSeq = inviteRequest.GetHeader <SipCSeqValue>(SipHeader.CSeq); if (vCSeq == null) { throw new SipException("INVITE request is missing header: [CSeq]"); } ackRequest.AddHeader(SipHeader.Via, via.Text); ackRequest.AddHeader(SipHeader.To, to.Text); ackRequest.AddHeader(SipHeader.From, from.Text); ackRequest.AddHeader(SipHeader.Contact, contact.Text); ackRequest.AddHeader(SipHeader.CallID, callID.Text); ackRequest.AddHeader(SipHeader.CSeq, new SipCSeqValue(vCSeq.Number, "ACK")); ackRequest.AddHeader(SipHeader.MaxForwards, SipHelper.MaxForwards); ackRequest.AddHeader(SipHeader.UserAgent, agent.Core.Settings.UserAgent); if (route != null) { ackRequest.Headers.Add(SipHeader.Route, route.Clone()); } return(ackRequest); }
/// <summary> /// Initiates an asynchronous SIP request transaction. /// </summary> /// <param name="request">The <see cref="SipRequest" /> to be submitted.</param> /// <param name="dialog">The <see cref="SipDialog" /> for requests that initiate a dialog (or <c>null</c>).</param> /// <param name="callback">The delegate to be called when the operation completes (or <c>null</c>).</param> /// <param name="state">Application defined state (or <c>null</c>).</param> /// <returns>The <see cref="IAsyncResult" /> to be used to track the operation's progress.</returns> /// <remarks> /// <para> /// All requests to <see cref="BeginRequest(SipRequest,SipDialog,AsyncCallback,object)" /> must be matched with a /// call to <see cref="EndRequest" />. /// </para> /// <note> /// This method adds reasonable <b>Call-ID</b> and <b>CSeq</b> headers to the request if these /// headers are not already present. /// </note> /// </remarks> public IAsyncResult BeginRequest(SipRequest request, SipDialog dialog, AsyncCallback callback, object state) { ClientAsyncResult arClient = new ClientAsyncResult(request, dialog, callback, state); SipValue viaValue; SipCSeqValue vCSeq; string transactionID; SipClientTransaction transaction; ISipTransport transport; NetworkBinding remoteEP; if (dialog != null && request.Method != SipMethod.Invite) { throw new InvalidOperationException("Dialogs may be created only for INVITE requests."); } arClient.Dialog = dialog; transport = router.SelectTransport(this, request, out remoteEP); if (transport == null) { throw new SipException("No approriate transport is available."); } // Initialize the request's Via header and transaction ID as necessary. transactionID = SipHelper.GenerateBranchID(); viaValue = new SipValue(string.Format("SIP/2.0/{0} {1}", transport.Name, transport.Settings.ExternalBinding.Address)); viaValue["branch"] = transactionID; viaValue["rport"] = string.Empty; request.PrependHeader(SipHeader.Via, viaValue); // Initialize common headers as necessary if (!request.ContainsHeader(SipHeader.CallID)) { request.AddHeader(SipHeader.CallID, SipHelper.GenerateCallID()); } vCSeq = request.GetHeader <SipCSeqValue>(SipHeader.CSeq); if (vCSeq == null) { vCSeq = new SipCSeqValue(SipHelper.GenCSeq(), request.MethodText); request.AddHeader(SipHeader.CSeq, vCSeq); } // Initialize the transaction transaction = new SipClientTransaction(this, request, transactionID, transport, remoteEP); transaction.AgentState = arClient; // Handle initial dialog INVITE specific initialization if (dialog != null && request.Method == SipMethod.Invite && dialog.State == SipDialogState.Waiting) { // Client-side dialogs need to know the transaction so // they'll be able to send the confirming ACK. dialog.InitiatingTransaction = transaction; // Dialogs need to know about the sequence number used in INVITE requests so // that the ACK can be generated with the same sequence number. dialog.AckCSeq = vCSeq.Number; // The dialog has been intialized enough to be added to the core's // early dialog table. core.AddEarlyDialog(dialog); } // Start the transaction using (TimedLock.Lock(this)) { transactions.Add(transactionID, transaction); } transaction.Start(); arClient.Started(); return(arClient); }