/// <summary>
/// New transaction ACK requests are for 2xx responses, i.e. INVITE accepted and 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.
///
/// 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 GetNewTransactionACKRequest(SIPResponse sipResponse, SIPURI ackURI, SIPEndPoint localSIPEndPoint)
{
SIPRequest ackRequest = new SIPRequest(SIPMethodsEnum.ACK, ackURI.ToString())
{
LocalSIPEndPoint = localSIPEndPoint
};
SIPHeader header = new SIPHeader(TransactionRequest.Header.From, sipResponse.Header.To, sipResponse.Header.CSeq, sipResponse.Header.CallId)
{
CSeqMethod = SIPMethodsEnum.ACK,
AuthenticationHeader = TransactionRequest.Header.AuthenticationHeader,
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;
SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, CallProperties.CreateBranchId());
ackRequest.Header.Vias.PushViaHeader(viaHeader);
return(ackRequest);
}
public string CreateBranchId()
{
string routeStr = (Header.Routes != null) ? Header.Routes.ToString() : null;
string toTagStr = (Header.To != null) ? Header.To.ToTag : null;
string fromTagStr = (Header.From != null) ? Header.From.FromTag : null;
string topViaStr = (Header.Vias != null && Header.Vias.TopViaHeader != null) ? Header.Vias.TopViaHeader.ToString() : null;
return(CallProperties.CreateBranchId(
SIPConstants.SIP_BRANCH_MAGICCOOKIE,
toTagStr,
fromTagStr,
Header.CallId,
URI.ToString(),
topViaStr,
Header.CSeq,
routeStr,
Header.ProxyRequire,
null));
}
private SIPRequest GetByeRequest(SIPEndPoint localSIPEndPoint)
{
SIPRequest byeRequest = new SIPRequest(SIPMethodsEnum.BYE, RemoteTarget);
SIPFromHeader byeFromHeader = SIPFromHeader.ParseFromHeader(LocalUserField.ToString());
SIPToHeader byeToHeader = SIPToHeader.ParseToHeader(RemoteUserField.ToString());
int cseq = CSeq + 1;
SIPHeader byeHeader = new SIPHeader(byeFromHeader, byeToHeader, cseq, CallId);
byeHeader.CSeqMethod = SIPMethodsEnum.BYE;
byeRequest.Header = byeHeader;
byeRequest.Header.Routes = RouteSet;
byeRequest.Header.ProxySendFrom = ProxySendFrom;
SIPViaHeader viaHeader = new SIPViaHeader(localSIPEndPoint, CallProperties.CreateBranchId());
byeRequest.Header.Vias.PushViaHeader(viaHeader);
return(byeRequest);
}
private SIPRequest GetDummyINVITERequest(SIPURI dummyURI)
{
string dummyFrom = "<sip:[email protected]>";
string dummyContact = "sip:127.0.0.1:1234";
SIPRequest inviteRequest = new SIPRequest(SIPMethodsEnum.INVITE, dummyURI);
SIPHeader inviteHeader = new SIPHeader(SIPFromHeader.ParseFromHeader(dummyFrom), new SIPToHeader(null, dummyURI, null), 1, CallProperties.CreateNewCallId());
inviteHeader.From.FromTag = CallProperties.CreateNewTag();
inviteHeader.Contact = SIPContactHeader.ParseContactHeader(dummyContact);
inviteHeader.CSeqMethod = SIPMethodsEnum.INVITE;
inviteHeader.UserAgent = "unittest";
inviteRequest.Header = inviteHeader;
SIPViaHeader viaHeader = new SIPViaHeader("127.0.0.1", 1234, CallProperties.CreateBranchId(), SIPProtocolsEnum.udp);
inviteRequest.Header.Vias.PushViaHeader(viaHeader);
inviteRequest.Body = "dummy";
inviteRequest.Header.ContentLength = inviteRequest.Body.Length;
inviteRequest.Header.ContentType = "application/sdp";
return(inviteRequest);
}
