/// <summary>
/// Creates a CANCEL <see cref="SipRequest" /> for this request.
/// </summary>
/// <returns>The CANCEL <see cref="SipRequest" />.</returns>
public SipRequest CreateCancelRequest()
{
SipRequest cancelRequest = new SipRequest(SipMethod.Cancel, this.uri, this.SipVersion);
SipHeader header;
SipCSeqValue vCSeq;
header = this[SipHeader.Via];
if (header == null || header.Values.Length == 0)
{
throw new SipException("[Via] header is required when generating a CANCEL.");
}
cancelRequest.SetHeader(SipHeader.Via, header.Text);
header = this[SipHeader.Route];
if (header != null)
{
cancelRequest.Headers.Add(SipHeader.Route, header);
}
header = this[SipHeader.To];
if (header != null)
{
cancelRequest.Headers.Add(SipHeader.To, header.Clone());
}
header = this[SipHeader.From];
if (header != null)
{
cancelRequest.Headers.Add(SipHeader.From, header.Clone());
}
header = this[SipHeader.CallID];
if (header == null)
{
throw new SipException("[Call-ID] header is required when generating a CANCEL.");
}
cancelRequest.Headers.Add(SipHeader.CallID, header.Clone());
vCSeq = this.GetHeader <SipCSeqValue>(SipHeader.CSeq);
if (vCSeq == null)
{
throw new SipException("[CSeq] header is required when generating a CANCEL.");
}
cancelRequest.SetCSeq(vCSeq.Number);
return(cancelRequest);
}
/// <summary>
/// The managing <see cref="ISipAgent" /> is responsible for calling this
/// method whenever it receives requests correlated to this transaction.
/// </summary>
/// <param name="request">The received <see cref="SipRequest" />.</param>
public void OnRequest(SipRequest request)
{
SipRequest callbackMsg = null;
bool callOnRequest = false;
bool callOnInviteBegin = false;
bool callOnInviteComplete = false;
try
{
request.SourceTransaction = this;
using (TimedLock.Lock(agent))
{
if (this.request == null)
{
SipViaValue viaValue;
SipContactValue toValue;
NetworkBinding sentBy;
IPAddress address;
// This is the initial transaction request.
this.request = request;
// Handle the Via "received" and "rport" header parameters (mostly) as described on page
// RFC 3261 (page 145) and RFC 3581 (page 4).
viaValue = request.GetHeader <SipViaValue>(SipHeader.Via);
if (viaValue == null)
{
// Illegal request
SetState(SipTransactionState.Terminated);
return;
}
sentBy = viaValue.SentByBinding;
if (sentBy == null || sentBy.IsHost || sentBy.Address != request.RemoteEndpoint.Address)
{
viaValue.Received = request.RemoteEndpoint.Address.ToString();
}
if (viaValue.RPort != null)
{
viaValue.RPort = request.RemoteEndpoint.Port.ToString();
}
// Determine the destination network endpoint based on the
// rules described on RFC 3261 (page 146).
if (request.SourceTransport.IsStreaming)
{
// $todo(jeff.lill):
//
// This implementation is incomplete. To be fully
// compliant with the RFC, I'd have to check to
// see if the connection is still present in the
// transport and if not, use the received and
// rport values as described.
remoteEP = request.RemoteEndpoint;
}
else
{
if (viaValue.MAddr != null)
{
if (!IPAddress.TryParse(viaValue.MAddr, out address))
{
SipException e;
// Illegal request
SetState(SipTransactionState.Terminated);
e = new SipException("Illegal request: Invalid [Via: maddr].");
e.Transport = transport.Name;
e.SourceEndpoint = request.RemoteEndpoint;
e.BadMessage = request;
throw e;
}
remoteEP = new NetworkBinding(address, viaValue.SentByBinding.Port);
}
else
{
remoteEP = request.RemoteEndpoint;
}
}
// INVITE and non-INVITE requests have different state machines.
if (request.Method == SipMethod.Invite)
{
// Start an INVITE transaction
SetState(SipTransactionState.InviteProceeding);
// If the request has a "To" header without a "tag" parameter then
// generate a tag. Note that this code will cause provisional INVITE
// responses to include a generated tag which the RFC indicates
// SHOULD NOT be done. But, it's much safer to do this once here
// for all transaction types, avoiding special cases, and besides,
// I've noticed that Asterisk includes a tag in its provisional
// INVITE responses.
toValue = request.GetHeader <SipContactValue>(SipHeader.To);
if (toValue != null)
{
if (toValue["tag"] == null)
{
toValue["tag"] = SipHelper.GenerateTagID();
}
request.SetHeader(SipHeader.To, toValue);
}
// Always send an initial provisional trying response.
provisionalResponse = request.CreateResponse(SipStatus.Trying, null);
SendResponse(provisionalResponse);
// Setup to call the agent's OnInviteBegin() method.
callOnInviteBegin = true;
callbackMsg = request;
}
else if (request.Method == SipMethod.Ack)
{
// Allow an ACK request to drop through to the state machine.
}
else
{
// Start a non-INVITE transaction
SetState(SipTransactionState.Trying);
// Setup to call the agent's OnRequest() method.
callOnRequest = true;
callbackMsg = request;
}
return;
}
// Handle state specific processing
switch (base.State)
{
default:
case SipTransactionState.Unknown:
SysLog.LogError("Unexpected SIP transaction state.");
SetState(SipTransactionState.Terminated);
return;
case SipTransactionState.InviteCalling:
break;
case SipTransactionState.InviteProceeding:
if (provisionalResponse != null)
{
transport.Send(remoteEP, provisionalResponse);
}
break;
case SipTransactionState.InviteCompleted:
if (request.Method == SipMethod.Ack)
{
SetState(SipTransactionState.InviteConfirmed);
// Setup to call OnInviteComplete(ack);
callOnInviteComplete = true;
callbackMsg = request;
return;
}
Assertion.Test(finalResponse != null);
transport.Send(remoteEP, finalResponse);
break;
case SipTransactionState.InviteConfirmed:
break;
case SipTransactionState.Trying:
break;
case SipTransactionState.Proceeding:
Assertion.Test(provisionalResponse != null);
transport.Send(remoteEP, provisionalResponse);
break;
case SipTransactionState.Completed:
Assertion.Test(finalResponse != null);
transport.Send(remoteEP, finalResponse);
break;
case SipTransactionState.Terminated:
break;
}
}
}
finally
{
// Handle the agent callbacks outside of the lock to avoid
// deadlock issues.
if (callOnRequest)
{
agent.OnRequest(this, callbackMsg);
}
if (callOnInviteBegin)
{
agent.OnInviteBegin(this, request);
}
if (callOnInviteComplete)
{
agent.OnInviteComplete(this, this.request, finalResponse, callbackMsg);
}
}
}
