/// <summary>
/// Handler for when an in dialog request is received on an established call.
/// Typical types of request will be re-INVITES for things like putting a call on or
/// off hold and REFER requests for transfers. Some in dialog request types, such
/// as re-INVITES have specific events so they can be bubbled up to the
/// application to deal with.
/// </summary>
/// <param name="sipRequest">The in dialog request received.</param>
private async Task DialogRequestReceivedAsync(SIPRequest sipRequest)
{
if (sipRequest.Method == SIPMethodsEnum.BYE)
{
logger.LogInformation($"Remote call party hungup {sipRequest.StatusLine}.");
Dialogue.DialogueState = SIPDialogueStateEnum.Terminated;
SIPNonInviteTransaction byeTx = new SIPNonInviteTransaction(m_transport, sipRequest, null);
byeTx.SendResponse(SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Ok, null));
CallEnded();
}
else if (sipRequest.Method == SIPMethodsEnum.INVITE)
{
logger.LogDebug($"Re-INVITE request received {sipRequest.StatusLine}.");
UASInviteTransaction reInviteTransaction = new UASInviteTransaction(m_transport, sipRequest, m_outboundProxy);
try
{
SDP offer = SDP.ParseSDPDescription(sipRequest.Body);
var setRemoteResult = MediaSession.SetRemoteDescription(offer);
if (setRemoteResult != SetDescriptionResultEnum.OK)
{
logger.LogWarning($"Unable to set remote description from reINVITE request {setRemoteResult}");
var notAcceptableResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.NotAcceptable, setRemoteResult.ToString());
reInviteTransaction.SendFinalResponse(notAcceptableResponse);
}
else
{
var answerSdp = MediaSession.CreateAnswer(null);
CheckRemotePartyHoldCondition(MediaSession.RemoteDescription);
Dialogue.RemoteSDP = sipRequest.Body;
Dialogue.SDP = answerSdp.ToString();
Dialogue.RemoteCSeq = sipRequest.Header.CSeq;
var okResponse = reInviteTransaction.GetOkResponse(SDP.SDP_MIME_CONTENTTYPE, Dialogue.SDP);
reInviteTransaction.SendFinalResponse(okResponse);
}
}
catch (Exception ex)
{
logger.LogError(ex, "MediaSession can't process the re-INVITE request.");
if (OnReinviteRequest == null)
{
// The application isn't prepared to accept re-INVITE requests and we can't work out what it was for.
// We'll reject as gently as we can to try and not lose the call.
SIPResponse notAcceptableResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.NotAcceptable, null);
reInviteTransaction.SendFinalResponse(notAcceptableResponse);
}
else
{
// The application is going to handle the re-INVITE request. We'll send a Trying response as a precursor.
SIPResponse tryingResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Trying, null);
await reInviteTransaction.SendProvisionalResponse(tryingResponse).ConfigureAwait(false);
OnReinviteRequest.Invoke(reInviteTransaction);
}
}
}
else if (sipRequest.Method == SIPMethodsEnum.OPTIONS)
{
//Log_External(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.AppServer, SIPMonitorEventTypesEnum.DialPlan, "OPTIONS request for established dialogue " + dialogue.DialogueName + ".", dialogue.Owner));
SIPResponse okResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Ok, null);
okResponse.Body = Dialogue.RemoteSDP;
okResponse.Header.ContentLength = okResponse.Body.Length;
okResponse.Header.ContentType = m_sdpContentType;
await SendResponseAsync(okResponse).ConfigureAwait(false);
}
else if (sipRequest.Method == SIPMethodsEnum.MESSAGE)
{
//Log_External(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.AppServer, SIPMonitorEventTypesEnum.DialPlan, "MESSAGE for call " + sipRequest.URI.ToString() + ": " + sipRequest.Body + ".", dialogue.Owner));
SIPResponse okResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Ok, null);
await m_transport.SendResponseAsync(okResponse).ConfigureAwait(false);
}
else if (sipRequest.Method == SIPMethodsEnum.REFER)
{
if (sipRequest.Header.ReferTo.IsNullOrBlank())
{
// A REFER request must have a Refer-To header.
//Log_External(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.AppServer, SIPMonitorEventTypesEnum.DialPlan, "Bad REFER request, no Refer-To header.", dialogue.Owner));
SIPResponse invalidResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.BadRequest, "Missing mandatory Refer-To header");
await SendResponseAsync(invalidResponse).ConfigureAwait(false);
}
else
{
//TODO: Add handling logic for in transfer requests from the remote call party.
}
}
else if (sipRequest.Method == SIPMethodsEnum.NOTIFY)
{
SIPResponse okResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Ok, null);
await SendResponseAsync(okResponse).ConfigureAwait(false);
if (sipRequest.Body?.Length > 0 && sipRequest.Header.ContentType?.Contains(m_sipReferContentType) == true)
{
OnTransferNotify?.Invoke(sipRequest.Body);
}
}
}