/// <summary>
/// Is called when client transaction has timed out.
/// </summary>
/// <param name="sender">Sender.</param>
/// <param name="e">Event data.</param>
private void ClientTransaction_TimedOut(object sender, EventArgs e)
{
lock (m_pLock){
/* RFC 3261 8.1.2.
* The UAC SHOULD follow the procedures defined in [4] for stateful
* elements, trying each address until a server is contacted. Each try
* constitutes a new transaction, and therefore each carries a different
* topmost Via header field value with a new branch parameter.
* Furthermore, the transport value in the Via header field is set to
* whatever transport was determined for the target server.
*/
if (m_pHops.Count > 0)
{
CleanUpActiveTransaction();
SendToNextHop();
}
/* 8.1.3.1 Transaction Layer Errors
* In some cases, the response returned by the transaction layer will
* not be a SIP message, but rather a transaction layer error. When a
* timeout error is received from the transaction layer, it MUST be
* treated as if a 408 (Request Timeout) status code has been received.
* If a fatal transport error is reported by the transport layer
* (generally, due to fatal ICMP errors in UDP or connection failures in
* TCP), the condition MUST be treated as a 503 (Service Unavailable)
* status code.
*/
else
{
OnResponseReceived(m_pStack.CreateResponse(SIP_ResponseCodes.x408_Request_Timeout, m_pRequest));
OnCompleted();
}
}
}
/// <summary>
/// Processes specified request through this dialog.
/// </summary>
/// <param name="e">Method arguments.</param>
/// <returns>Returns true if this dialog processed specified response, otherwise false.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>e</b> is null reference.</exception>
protected internal virtual bool ProcessRequest(SIP_RequestReceivedEventArgs e)
{
if (e == null)
{
throw new ArgumentNullException("e");
}
if (e.Request.RequestLine.Method == SIP_Methods.BYE)
{
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x200_Ok, e.Request));
m_IsTerminatedByRemoteParty = true;
OnTerminatedByRemoteParty(e);
SetState(SIP_DialogState.Terminated, true);
return(true);
}
return(false);
}
/// <summary>
/// This method is called when new request is received.
/// </summary>
/// <param name="e">Request event arguments.</param>
private void OnRequestReceived(SIP_RequestReceivedEventArgs e)
{
SIP_Request request = e.Request;
try{
#region Statefull
// Statefull
if ((m_ProxyMode & SIP_ProxyMode.Statefull) != 0)
{
// Statefull proxy is transaction statefull proxy only,
// what don't create dialogs and keep dialog state.
/* RFC 3261 16.10.
* StateFull proxy:
* If a matching response context is found, the element MUST
* immediately return a 200 (OK) response to the CANCEL request.
*
* If a response context is not found, the element does not have any
* knowledge of the request to apply the CANCEL to. It MUST statelessly
* forward the CANCEL request (it may have statelessly forwarded the
* associated request previously).
*/
if (e.Request.RequestLine.Method == SIP_Methods.CANCEL)
{
// Don't do server transaction before we get CANCEL matching transaction.
SIP_ServerTransaction trToCancel = m_pStack.TransactionLayer.MatchCancelToTransaction(e.Request);
if (trToCancel != null)
{
trToCancel.Cancel();
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x200_Ok, request));
}
else
{
ForwardRequest(false, e, true);
}
}
// ACK never creates transaction, it's always passed directly to transport layer.
else if (e.Request.RequestLine.Method == SIP_Methods.ACK)
{
ForwardRequest(false, e, true);
}
else
{
ForwardRequest(true, e, true);
}
}
#endregion
#region B2BUA
// B2BUA
else if ((m_ProxyMode & SIP_ProxyMode.B2BUA) != 0)
{
m_pB2BUA.OnRequestReceived(e);
}
#endregion
#region Stateless
// Stateless
else if ((m_ProxyMode & SIP_ProxyMode.Stateless) != 0)
{
// Stateless proxy don't do transaction, just forwards all.
ForwardRequest(false, e, true);
}
#endregion
#region Proxy won't accept command
else
{
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x501_Not_Implemented, request));
}
#endregion
}
catch (Exception x) {
try{
m_pStack.TransportLayer.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x500_Server_Internal_Error + ": " + x.Message, e.Request));
}
catch {
// Skip transport layer exception if send fails.
}
// Don't raise OnError for transport errors.
if (!(x is SIP_TransportException))
{
m_pStack.OnError(x);
}
}
}
/// <summary>
/// Handles REGISTER method.
/// </summary>
/// <param name="e">Request event arguments.</param>
internal void Register(SIP_RequestReceivedEventArgs e)
{
/* RFC 3261 10.3 Processing REGISTER Requests.
* 1. The registrar inspects the Request-URI to determine whether it
* has access to bindings for the domain identified in the
* Request-URI. If not, and if the server also acts as a proxy
* server, the server SHOULD forward the request to the addressed
* domain, following the general behavior for proxying messages
* described in Section 16.
*
* 2. To guarantee that the registrar supports any necessary extensions,
* the registrar MUST process the Require header field.
*
* 3. A registrar SHOULD authenticate the UAC.
*
* 4. The registrar SHOULD determine if the authenticated user is
* authorized to modify registrations for this address-of-record.
* For example, a registrar might consult an authorization
* database that maps user names to a list of addresses-of-record
* for which that user has authorization to modify bindings. If
* the authenticated user is not authorized to modify bindings,
* the registrar MUST return a 403 (Forbidden) and skip the
* remaining steps.
*
* 5. The registrar extracts the address-of-record from the To header
* field of the request. If the address-of-record is not valid
* for the domain in the Request-URI, the registrar MUST send a
* 404 (Not Found) response and skip the remaining steps. The URI
* MUST then be converted to a canonical form. To do that, all
* URI parameters MUST be removed (including the user-param), and
* any escaped characters MUST be converted to their unescaped
* form. The result serves as an index into the list of bindings.
*
* 6. The registrar checks whether the request contains the Contact
* header field. If not, it skips to the last step. If the
* Contact header field is present, the registrar checks if there
* is one Contact field value that contains the special value "*"
* and an Expires field. If the request has additional Contact
* fields or an expiration time other than zero, the request is
* invalid, and the server MUST return a 400 (Invalid Request) and
* skip the remaining steps. If not, the registrar checks whether
* the Call-ID agrees with the value stored for each binding. If
* not, it MUST remove the binding. If it does agree, it MUST
* remove the binding only if the CSeq in the request is higher
* than the value stored for that binding. Otherwise, the update
* MUST be aborted and the request fails.
*
* 7. The registrar now processes each contact address in the Contact
* header field in turn. For each address, it determines the
* expiration interval as follows:
*
* - If the field value has an "expires" parameter, that value
* MUST be taken as the requested expiration.
*
* - If there is no such parameter, but the request has an
* Expires header field, that value MUST be taken as the requested expiration.
*
* - If there is neither, a locally-configured default value MUST
* be taken as the requested expiration.
*
* The registrar MAY choose an expiration less than the requested
* expiration interval. If and only if the requested expiration
* interval is greater than zero AND smaller than one hour AND
* less than a registrar-configured minimum, the registrar MAY
* reject the registration with a response of 423 (Interval Too
* Brief). This response MUST contain a Min-Expires header field
* that states the minimum expiration interval the registrar is
* willing to honor. It then skips the remaining steps.
*
* For each address, the registrar then searches the list of
* current bindings using the URI comparison rules. If the
* binding does not exist, it is tentatively added. If the
* binding does exist, the registrar checks the Call-ID value. If
* the Call-ID value in the existing binding differs from the
* Call-ID value in the request, the binding MUST be removed if
* the expiration time is zero and updated otherwise. If they are
* the same, the registrar compares the CSeq value. If the value
* is higher than that of the existing binding, it MUST update or
* remove the binding as above. If not, the update MUST be
* aborted and the request fails.
*
* This algorithm ensures that out-of-order requests from the same
* UA are ignored.
*
* Each binding record records the Call-ID and CSeq values from
* the request.
*
* The binding updates MUST be committed (that is, made visible to
* the proxy or redirect server) if and only if all binding
* updates and additions succeed. If any one of them fails (for
* example, because the back-end database commit failed), the
* request MUST fail with a 500 (Server Error) response and all
* tentative binding updates MUST be removed.
*
* 8. The registrar returns a 200 (OK) response. The response MUST
* contain Contact header field values enumerating all current
* bindings. Each Contact value MUST feature an "expires"
* parameter indicating its expiration interval chosen by the
* registrar. The response SHOULD include a Date header field.
*/
SIP_ServerTransaction transaction = e.ServerTransaction;
SIP_Request request = e.Request;
SIP_Uri to = null;
string userName = "";
// Probably we need to do validate in SIP stack.
#region Validate request
if (SIP_Utils.IsSipOrSipsUri(request.To.Address.Uri.ToString()))
{
to = (SIP_Uri)request.To.Address.Uri;
}
else
{
transaction.SendResponse(
m_pStack.CreateResponse(
SIP_ResponseCodes.x400_Bad_Request + ": To: value must be SIP or SIPS URI.", request));
return;
}
#endregion
#region 1. Check if we are responsible for Request-URI domain
// if(m_pProxy.OnIsLocalUri(e.Request.Uri)){
// }
// TODO:
#endregion
#region 2. Check that all required extentions supported
#endregion
#region 3. Authenticate request
if (!m_pProxy.AuthenticateRequest(e, out userName))
{
return;
}
#endregion
#region 4. Check if user user is authorized to modify registrations
// We do this in next step(5.).
#endregion
#region 5. Check if address of record exists
if (!m_pProxy.OnAddressExists(to.Address))
{
transaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x404_Not_Found, request));
return;
}
else if (!OnCanRegister(userName, to.Address))
{
transaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x403_Forbidden, request));
return;
}
#endregion
#region 6. Process * Contact if exists
// Check if we have star contact.
SIP_t_ContactParam starContact = null;
foreach (SIP_t_ContactParam c in request.Contact.GetAllValues())
{
if (c.IsStarContact)
{
starContact = c;
break;
}
}
// We have star contact.
if (starContact != null)
{
if (request.Contact.GetAllValues().Length > 1)
{
transaction.SendResponse(
m_pStack.CreateResponse(
SIP_ResponseCodes.x400_Bad_Request +
": RFC 3261 10.3.6 -> If star(*) present, only 1 contact allowed.",
request));
return;
}
else if (starContact.Expires != 0)
{
transaction.SendResponse(
m_pStack.CreateResponse(
SIP_ResponseCodes.x400_Bad_Request +
": RFC 3261 10.3.6 -> star(*) contact parameter 'expires' value must be always '0'.",
request));
return;
}
// Remove bindings.
SIP_Registration reg = m_pRegistrations[to.Address];
if (reg != null)
{
foreach (SIP_RegistrationBinding b in reg.Bindings)
{
if (request.CallID != b.CallID || request.CSeq.SequenceNumber > b.CSeqNo)
{
b.Remove();
}
}
}
}
#endregion
#region 7. Process Contact values
if (starContact == null)
{
SIP_Registration reg = m_pRegistrations[to.Address];
if (reg == null)
{
reg = new SIP_Registration(userName, to.Address);
m_pRegistrations.Add(reg);
}
// We may do updates in batch only.
// We just validate all values then do update(this ensures that update doesn't fail).
// Check expires and CSeq.
foreach (SIP_t_ContactParam c in request.Contact.GetAllValues())
{
if (c.Expires == -1)
{
c.Expires = request.Expires;
}
if (c.Expires == -1)
{
c.Expires = m_pProxy.Stack.MinimumExpireTime;
}
// We must accept 0 values - means remove contact.
if (c.Expires != 0 && c.Expires < m_pProxy.Stack.MinimumExpireTime)
{
SIP_Response resp = m_pStack.CreateResponse(
SIP_ResponseCodes.x423_Interval_Too_Brief, request);
resp.MinExpires = m_pProxy.Stack.MinimumExpireTime;
transaction.SendResponse(resp);
return;
}
SIP_RegistrationBinding currentBinding = reg.GetBinding(c.Address.Uri);
if (currentBinding != null && currentBinding.CallID == request.CallID &&
request.CSeq.SequenceNumber < currentBinding.CSeqNo)
{
transaction.SendResponse(
m_pStack.CreateResponse(
SIP_ResponseCodes.x400_Bad_Request + ": CSeq value out of order.", request));
return;
}
}
// Do binding updates.
reg.AddOrUpdateBindings(e.ServerTransaction.Flow,
request.CallID,
request.CSeq.SequenceNumber,
request.Contact.GetAllValues());
}
#endregion
#region 8. Create 200 OK response and return all current bindings
SIP_Response response = m_pStack.CreateResponse(SIP_ResponseCodes.x200_Ok, request);
response.Date = DateTime.Now;
SIP_Registration registration = m_pRegistrations[to.Address];
if (registration != null)
{
foreach (SIP_RegistrationBinding b in registration.Bindings)
{
// Don't list expired bindings what wait to be disposed.
if (b.TTL > 1)
{
response.Header.Add("Contact:", b.ToContactValue());
}
}
}
// Add Authentication-Info:, then client knows next nonce.
response.AuthenticationInfo.Add("qop=\"auth\",nextnonce=\"" +
m_pStack.DigestNonceManager.CreateNonce() + "\"");
transaction.SendResponse(response);
#endregion
}
/// <summary>
/// This method is called when SIP stack received new message.
/// </summary>
/// <param name="sender">Sender.</param>
/// <param name="e">Event data.</param>
private void m_pStack_RequestReceived(object sender, SIP_RequestReceivedEventArgs e)
{
// TODO: Performance: rise events on thread pool or see if this method called on pool aready, then we may not keep lock for events ?
if (e.Request.RequestLine.Method == SIP_Methods.CANCEL)
{
/* RFC 3261 9.2.
* If the UAS did not find a matching transaction for the CANCEL
* according to the procedure above, it SHOULD respond to the CANCEL
* with a 481 (Call Leg/Transaction Does Not Exist).
*
* Regardless of the method of the original request, as long as the
* CANCEL matched an existing transaction, the UAS answers the CANCEL
* request itself with a 200 (OK) response.
*/
SIP_ServerTransaction trToCancel = m_pStack.TransactionLayer.MatchCancelToTransaction(e.Request);
if (trToCancel != null)
{
trToCancel.Cancel();
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x200_Ok, e.Request));
}
else
{
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x481_Call_Transaction_Does_Not_Exist, e.Request));
}
}
else if (e.Request.RequestLine.Method == SIP_Methods.BYE)
{
/* RFC 3261 15.1.2.
* If the BYE does not match an existing dialog, the UAS core SHOULD generate a 481
* (Call/Transaction Does Not Exist) response and pass that to the server transaction.
*/
// TODO:
SIP_Dialog dialog = m_pStack.TransactionLayer.MatchDialog(e.Request);
if (dialog != null)
{
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x200_Ok, e.Request));
dialog.Terminate();
}
else
{
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x481_Call_Transaction_Does_Not_Exist, e.Request));
}
}
else if (e.Request.RequestLine.Method == SIP_Methods.INVITE)
{
// Supress INVITE retransmissions.
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(SIP_ResponseCodes.x100_Trying, e.Request));
// Create call.
SIP_UA_Call call = new SIP_UA_Call(this, e.ServerTransaction);
call.StateChanged += new EventHandler(Call_StateChanged);
m_pCalls.Add(call);
OnIncomingCall(call);
}
else
{
OnRequestReceived(e);
}
}
/// <summary>
/// This method is called when new request is received.
/// </summary>
/// <param name="e">Request event arguments.</param>
private void OnRequestReceived(SIP_RequestReceivedEventArgs e)
{
/* RFC 3261 16.12. ????????? Forward does all thse steps.
* 1. The proxy will inspect the Request-URI. If it indicates a
* resource owned by this proxy, the proxy will replace it with
* the results of running a location service. Otherwise, the
* proxy will not change the Request-URI.
*
* 2. The proxy will inspect the URI in the topmost Route header
* field value. If it indicates this proxy, the proxy removes it
* from the Route header field (this route node has been reached).
*
* 3. The proxy will forward the request to the resource indicated
* by the URI in the topmost Route header field value or in the
* Request-URI if no Route header field is present. The proxy
* determines the address, port and transport to use when
* forwarding the request by applying the procedures in [4] to that URI.
*/
SIP_Request request = e.Request;
try
{
#region Registrar
// Registrar
if ((m_ProxyMode & SIP_ProxyMode.Registrar) != 0 &&
request.RequestLine.Method == SIP_Methods.REGISTER)
{
m_pRegistrar.Register(e);
}
#endregion
#region Presence
/*
* // Presence
* else if((m_ProxyMode & SIP_ProxyMode.Presence) != 0 && (request.Method == "SUBSCRIBE" || request.Method == "NOTIFY")){
*
* }
*/
#endregion
#region Statefull
// Statefull
else if ((m_ProxyMode & SIP_ProxyMode.Statefull) != 0)
{
// Statefull proxy is transaction statefull proxy only,
// what don't create dialogs and keep dialog state.
/* RFC 3261 16.10.
* StateFull proxy:
* If a matching response context is found, the element MUST
* immediately return a 200 (OK) response to the CANCEL request.
*
* If a response context is not found, the element does not have any
* knowledge of the request to apply the CANCEL to. It MUST statelessly
* forward the CANCEL request (it may have statelessly forwarded the
* associated request previously).
*/
if (e.Request.RequestLine.Method == SIP_Methods.CANCEL)
{
// Don't do server transaction before we get CANCEL matching transaction.
SIP_ServerTransaction trToCancel =
m_pStack.TransactionLayer.MatchCancelToTransaction(e.Request);
if (trToCancel != null)
{
trToCancel.Cancel();
e.ServerTransaction.SendResponse(m_pStack.CreateResponse(
SIP_ResponseCodes.x200_Ok, request));
}
else
{
ForwardRequest(false, e);
}
}
// ACK never creates transaction, it's always passed directly to transport layer.
else if (e.Request.RequestLine.Method == SIP_Methods.ACK)
{
ForwardRequest(false, e);
}
else
{
ForwardRequest(true, e);
}
}
#endregion
#region B2BUA
// B2BUA
else if ((m_ProxyMode & SIP_ProxyMode.B2BUA) != 0)
{
m_pB2BUA.OnRequestReceived(e);
}
#endregion
#region Stateless
// Stateless
else if ((m_ProxyMode & SIP_ProxyMode.Stateless) != 0)
{
// Stateless proxy don't do transaction, just forwards all.
ForwardRequest(false, e);
}
#endregion
#region Proxy won't accept command
else
{
e.ServerTransaction.SendResponse(
m_pStack.CreateResponse(SIP_ResponseCodes.x501_Not_Implemented, request));
}
#endregion
}
catch (Exception x)
{
try
{
m_pStack.TransportLayer.SendResponse(
m_pStack.CreateResponse(
SIP_ResponseCodes.x500_Server_Internal_Error + ": " + x.Message, e.Request));
}
catch
{
// Skip transport layer exception if send fails.
}
// Don't raise OnError for transport errors.
if (!(x is SIP_TransportException))
{
m_pStack.OnError(x);
}
}
}