/// <summary>
/// The managing <see cref="ISipAgent" /> is responsible for calling this
/// method whenever it receives responses correlated to this transaction.
/// </summary>
/// <param name="transport">The source <see cref="ISipTransport" />.</param>
/// <param name="response">The received <see cref="SipResponse" />.</param>
public void OnResponse(ISipTransport transport, SipResponse response)
{
bool callOnComplete = false;
bool callOnProceeding = false;
bool callOnInviteComplete = false;
SipResponse callbackMsg = null;
SipStatus status = SipStatus.OK;
SipCSeqValue vCSeq;
this.transport = transport;
try
{
response.SourceTransaction = this;
using (TimedLock.Lock(agent))
{
// Ignore messages without a sequence number
//
// $todo(jeff.lill): Probably should check the method too
vCSeq = response.GetHeader <SipCSeqValue>(SipHeader.CSeq);
if (vCSeq == null)
{
return;
}
// Handle state specific processing
switch (base.State)
{
default:
case SipTransactionState.Unknown:
SysLog.LogError("Unexpected SIP transaction state.");
SetState(SipTransactionState.Terminated);
// Setup to call the agent's completion method
callOnComplete = true;
callbackMsg = null;
status = SipStatus.Stack_ProtocolError;
return;
case SipTransactionState.InviteCalling:
if (!request.MatchCSeq(response))
{
return; // Ignore responses whose CSeq header doesn't match the request
}
if (response.IsProvisional)
{
// Provisional response.
SetState(SipTransactionState.InviteProceeding);
// Setup to call the agent's proceeding method
callOnProceeding = true;
callbackMsg = response;
status = response.Status;
return;
}
if (response.IsNonSuccessFinal)
{
// Final response non-2xx response. Generate and
// send the ACK request to the server to squelch
// any further responses and then enter the
// InviteCompleted state to absorb any responses
// that do make it through.
ackRequest = CreateAckRequest(request, response);
transport.Send(remoteEP, ackRequest);
SetState(SipTransactionState.InviteCompleted);
// Setup to call the agent's invite completed method
callOnInviteComplete = true;
callbackMsg = response;
status = response.Status;
return;
}
// Must be a 2xx response. Setup to call the agent's
// completed method and enter the terminated state
// without sending an ACK request.
//
// Note that the agent is required to do this as
// described in RFC 3261 on pages 128-129.
SetState(SipTransactionState.Terminated);
callOnInviteComplete = true;
callbackMsg = response;
status = response.Status;
break;
case SipTransactionState.InviteProceeding:
if (!request.MatchCSeq(response))
{
return; // Ignore responses whose CSeq header doesn't match the request
}
if (response.IsProvisional)
{
// Setup to call the agent's proceeding method
callOnProceeding = true;
callbackMsg = response;
status = response.Status;
return;
}
if (response.IsNonSuccessFinal)
{
// Final response non-2xx response. Generate and
// send the ACK request to the server to squelch
// any further responses and then enter the
// InviteCompleted state to absorb any responses
// that do make it through.
// $todo(jeff.lill):
//
// I need to figure out a way to
// map to the dialog so that it
// can generate the ACK rather than
// doing this locally.
ackRequest = CreateAckRequest(request, response);
transport.Send(remoteEP, ackRequest);
SetState(SipTransactionState.InviteCompleted);
// Setup to call the agent's invite completed method
callOnInviteComplete = true;
callbackMsg = response;
status = response.Status;
return;
}
// Must be a 2xx response. Setup to call the agent's
// completed method and enter the terminated state
// without sending an ACK request.
//
// Note that the agent is required to do this as
// described in RFC 3261 on pages 128-129.
SetState(SipTransactionState.Terminated);
callOnInviteComplete = true;
callbackMsg = response;
status = response.Status;
break;
case SipTransactionState.InviteCompleted:
// Retransmit the ACK if we get another final response
if (response.IsFinal)
{
transport.Send(remoteEP, ackRequest);
}
break;
case SipTransactionState.Trying:
if (!request.MatchCSeq(response))
{
return; // Ignore responses whose CSeq header doesn't match the request
}
if (response.IsProvisional)
{
// Provisional response.
SetState(SipTransactionState.Proceeding);
// Setup to call the agent's proceeding method
callOnProceeding = true;
callbackMsg = response;
status = response.Status;
return;
}
else
{
// Final response
SetState(SipTransactionState.Completed);
// Setup to call the agent's completion method
callOnComplete = true;
callbackMsg = response;
status = response.Status;
return;
}
case SipTransactionState.Proceeding:
if (!request.MatchCSeq(response))
{
return; // Ignore responses whose CSeq header doesn't match the request
}
if (response.IsProvisional)
{
// Setup to call the agent's proceeding method
callOnProceeding = true;
callbackMsg = response;
status = response.Status;
return;
}
// Final response.
SetState(SipTransactionState.Completed);
// Setup to call the agent's completion method
callOnComplete = true;
callbackMsg = response;
status = response.Status;
return;
case SipTransactionState.Completed:
break;
case SipTransactionState.Terminated:
break;
}
}
}
finally
{
// Handle the agent callbacks outside of the lock to avoid
// deadlock issues.
if (callOnProceeding)
{
agent.OnProceeding(this, callbackMsg);
}
if (callOnComplete)
{
agent.OnComplete(this, status, callbackMsg);
}
if (callOnInviteComplete)
{
agent.OnInviteComplete(this, status, response);
}
}
}
