/// <summary>
/// Create a dialog when we get a response to our INVITE request.
/// </summary>
/// <param name="request"></param>
/// <param name="response"></param>
/// <returns></returns>
/// <remarks>
/// Described in RFC321 Section 12.1.2 UAC Behavior
/// </remarks>
public Dialog CreateClientDialog(IRequest request, IResponse response)
{
// When a UAC sends a request that can establish a dialog (such as an
// INVITE) it MUST provide a SIP or SIPS URI with global scope (i.e.,
// the same SIP URI can be used in messages outside this dialog) in the
// Contact header field of the request. If the request has a Request-
// URI or a topmost Route header field value with a SIPS URI, the
// Contact header field MUST contain a SIPS URI.
var route = (Route) request.Headers[Route.ROUTE_LNAME];
if (request.Uri.Scheme == "sips" || (route != null && route.First.Uri.Scheme == "sips"))
{
if (request.Contact.Uri.Scheme != "sips")
throw new BadRequestException("Contact must use 'sips' if Request URI or first VIA uses 'sips'");
}
// 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.
var dialog = new Dialog();
dialog.State = DialogState.Early;
// If the request was sent over TLS, and the Request-URI contained a
// SIPS URI, the "secure" flag is set to TRUE.
dialog.IsSecure = request.Uri.Scheme.Equals("sips");
// 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.
dialog.RouteSet = response.Headers.Contains(Route.RECORD_ROUTE_LNAME)
? CopyAndReverse((Route) response.Headers[Route.RECORD_ROUTE_LNAME])
: new Route("Route");
// 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).
dialog.LocalSequenceNumber = request.CSeq.Number;
dialog.RemoteSequenceNumber = 0;
// The call identifier component of the
// dialog ID MUST be set to the value of the Call-ID in the request.
dialog.CallId = request.CallId;
// 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.
dialog.LocalTag = request.From.Parameters["tag"];
dialog.RemoteTag = response.To.Parameters["tag"];
// 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.
dialog.RemoteUri = request.To.Uri;
dialog.LocalUri = request.From.Uri;
dialog.Id = response.CallId + "-" + (response.From.Parameters["tag"] ?? string.Empty) + "-" +
(response.To.Parameters["tag"] ?? string.Empty);
dialog.Terminated += OnDialogTerminated;
lock (_dialogs)
_dialogs.Add(dialog.Id, dialog);
return dialog;
}
/// <summary>
/// Create a dialog from as an user agent server.
/// </summary>
/// <param name="transaction"></param>
/// <param name="response"></param>
/// <returns></returns>
/// <remarks>
/// Described in RFC3261 Section 12.1.1 UAS behavior
/// </remarks>
private Dialog CreateServerDialog(IServerTransaction transaction, IResponse response)
{
if (!transaction.Request.To.HasParameter("tag") && StatusCodeHelper.Is1xx(response))
{
_logger.Debug("Request do not have a to tag, ignoring response " + response + " for request " +
transaction.Request);
return null;
}
// See RFC3261 Section 12.1 Creation of a Dialog
if (StatusCodeHelper.Is3456xx(response))
{
_logger.Warning("Error response: " + response + " to request " + transaction.Request);
return null;
}
// RFC 3261 Section 12.1.2
var dialog = new Dialog();
// If the request was sent over TLS, and the Request-URI contained a SIPS URI,
// the "secure" flag is set to TRUE.
dialog.IsSecure = transaction.Request.Uri.Scheme == "sips";
//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.
dialog.RouteSet = response.Headers.Contains(Route.RECORD_ROUTE_LNAME)
? CopyAndReverse((Route) response.Headers[Route.RECORD_ROUTE_LNAME])
: new Route("Route");
// The remote target MUST be set to the URI
//from the Contact header field of the response.
dialog.RemoteTarget = response.Contact;
// 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.
dialog.LocalSequenceNumber = transaction.Request.CSeq.Number;
dialog.RemoteSequenceNumber = 0;
// 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.
dialog.CallId = transaction.Request.CallId;
dialog.LocalTag = transaction.Request.To.Parameters["tag"];
dialog.RemoteTag = response.From.Parameters["tag"];
// 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.
dialog.RemoteUri = transaction.Request.From.Uri;
dialog.LocalUri = transaction.Request.To.Uri;
dialog.Id = response.CallId + "-" + (response.To.Parameters["tag"] ?? string.Empty) + "-" +
(response.From.Parameters["tag"] ?? string.Empty);
return dialog;
}
