/// <summary> /// New transaction ACK requests are for 2xx responses, i.e. INVITE accepted and dialogue being created. /// </summary> /// <remarks> /// From RFC 3261 Chapter 13.2.2.4 - ACK for 2xx final responses /// /// IMPORTANT: /// an ACK for a 2xx final response is a new transaction and has a new branch ID. /// /// The UAC core MUST generate an ACK request for each 2xx received from /// the transaction layer. The header fields of the ACK are constructed /// in the same way as for any request sent within a dialog (see Section /// 12) with the exception of the CSeq and the header fields related to /// authentication. The sequence number of the CSeq header field MUST be /// the same as the INVITE being acknowledged, but the CSeq method MUST /// be ACK. The ACK MUST contain the same credentials as the INVITE. If /// the 2xx contains an offer (based on the rules above), the ACK MUST /// carry an answer in its body. If the offer in the 2xx response is not /// acceptable, the UAC core MUST generate a valid answer in the ACK and /// then send a BYE immediately. /// </remarks> private SIPRequest GetNewTransactionAcknowledgeRequest(SIPMethodsEnum method, SIPResponse sipResponse, SIPURI ackURI) { SIPRequest ackRequest = new SIPRequest(method, ackURI.ToString()); ackRequest.SetSendFromHints(sipResponse.LocalSIPEndPoint); SIPHeader header = new SIPHeader(TransactionRequest.Header.From, sipResponse.Header.To, sipResponse.Header.CSeq, sipResponse.Header.CallId); header.CSeqMethod = method; header.AuthenticationHeader = TransactionRequest.Header.AuthenticationHeader; header.ProxySendFrom = base.TransactionRequest.Header.ProxySendFrom; // If the UAS supplies a desired Record-Route list use that first. Otherwise fall back to any Route list used in the original transaction. if (sipResponse.Header.RecordRoutes != null) { header.Routes = sipResponse.Header.RecordRoutes.Reversed(); } else if (base.TransactionRequest.Header.Routes != null) { header.Routes = base.TransactionRequest.Header.Routes; } ackRequest.Header = header; ackRequest.Header.Vias.PushViaHeader(SIPViaHeader.GetDefaultSIPViaHeader()); return(ackRequest); }
/// <summary> /// In transaction ACK requests are for non-2xx responses, i.e. INVITE rejected and no dialogue being created. /// </summary> /// <remarks> /// From RFC 3261 Chapter 17.1.1.3 - ACK for non-2xx final responses /// /// IMPORTANT: /// an ACK for a non-2xx response will also have the same branch ID as the INVITE whose response it acknowledges. /// /// The ACK request constructed by the client transaction MUST contain /// values for the Call-ID, From, and Request-URI that are equal to the /// values of those header fields in the request passed to the transport /// by the client transaction (call this the "original request"). The To /// header field in the ACK MUST equal the To header field in the /// response being acknowledged, and therefore will usually differ from /// the To header field in the original request by the addition of the /// tag parameter. The ACK MUST contain a single Via header field, and /// this MUST be equal to the top Via header field of the original /// request. The CSeq header field in the ACK MUST contain the same /// value for the sequence number as was present in the original request, /// but the method parameter MUST be equal to "ACK". /// /// If the INVITE request whose response is being acknowledged had Route /// header fields, those header fields MUST appear in the ACK. This is /// to ensure that the ACK can be routed properly through any downstream /// stateless proxies. /// </remarks> private SIPRequest GetInTransactionACKRequest(SIPResponse sipResponse, SIPURI ackURI) { SIPRequest ackRequest = new SIPRequest(SIPMethodsEnum.ACK, ackURI.ToString()); ackRequest.SetSendFromHints(sipResponse.LocalSIPEndPoint); SIPHeader header = new SIPHeader(TransactionRequest.Header.From, sipResponse.Header.To, sipResponse.Header.CSeq, sipResponse.Header.CallId); header.CSeqMethod = SIPMethodsEnum.ACK; header.AuthenticationHeader = TransactionRequest.Header.AuthenticationHeader; header.Routes = base.TransactionRequest.Header.Routes; header.ProxySendFrom = base.TransactionRequest.Header.ProxySendFrom; ackRequest.Header = header; ackRequest.Header.Vias.PushViaHeader(SIPViaHeader.GetDefaultSIPViaHeader()); return(ackRequest); }