/// <summary>
/// Transaction matching see RFC3261 17.1.3 & 17.2.3 for matching client and server transactions respectively.
/// IMPORTANT NOTE this transaction matching applies to all requests and responses EXCEPT ACK requests to 2xx responses see 13.2.2.4.
/// For ACK's to 2xx responses the ACK represents a separate transaction. However for a UAS sending an INVITE response the ACK still has to be
/// matched to an existing server transaction in order to transition it to a Confirmed state.
///
/// ACK's:
/// - The ACK for a 2xx response will have the same CallId, From Tag and To Tag.
/// - An ACK for a non-2xx response will have the same branch ID as the INVITE whose response it acknowledges.
/// </summary>
/// <param name="sipRequest"></param>
/// <returns></returns>
public SIPTransaction GetTransaction(SIPRequest sipRequest)
{
// The branch is mandatory but it doesn't stop some UA's not setting it.
if (sipRequest.Header.Vias.TopViaHeader.Branch == null || sipRequest.Header.Vias.TopViaHeader.Branch.Trim().Length == 0)
{
return(null);
}
SIPMethodsEnum transactionMethod = (sipRequest.Method != SIPMethodsEnum.ACK) ? sipRequest.Method : SIPMethodsEnum.INVITE;
string transactionId = SIPTransaction.GetRequestTransactionId(sipRequest.Header.Vias.TopViaHeader.Branch, transactionMethod);
string contactAddress = (sipRequest.Header.Contact != null && sipRequest.Header.Contact.Count > 0) ? sipRequest.Header.Contact[0].ToString() : "no contact";
lock (m_transactions)
{
//if (transactionMethod == SIPMethodsEnum.ACK)
//{
//logger.Info("Matching ACK with contact=" + contactAddress + ", cseq=" + sipRequest.Header.CSeq + ".");
//}
if (transactionId != null && m_transactions.ContainsKey(transactionId))
{
//if (transactionMethod == SIPMethodsEnum.ACK)
//{
//logger.Info("ACK for contact=" + contactAddress + ", cseq=" + sipRequest.Header.CSeq + " was matched by branchid.");
//}
return(m_transactions[transactionId]);
}
else
{
// No normal match found so look fo a 2xx INVITE response waiting for an ACK.
if (sipRequest.Method == SIPMethodsEnum.ACK)
{
//logger.Debug("Looking for ACK transaction, branchid=" + sipRequest.Header.Via.TopViaHeader.Branch + ".");
foreach (SIPTransaction transaction in m_transactions.Values)
{
// According to the standard an ACK should only not get matched by the branchid on the original INVITE for a non-2xx response. However
// my Cisco phone created a new branchid on ACKs to 487 responses and since the Cisco also used the same Call-ID and From tag on the initial
// unauthenticated request and the subsequent authenticated request the condition below was found to be the best way to match the ACK.
/*if (transaction.TransactionType == SIPTransactionTypesEnum.Invite && transaction.TransactionFinalResponse != null && transaction.TransactionState == SIPTransactionStatesEnum.Completed)
* {
* if (transaction.TransactionFinalResponse.Header.CallId == sipRequest.Header.CallId &&
* transaction.TransactionFinalResponse.Header.To.ToTag == sipRequest.Header.To.ToTag &&
* transaction.TransactionFinalResponse.Header.From.FromTag == sipRequest.Header.From.FromTag)
* {
* return transaction;
* }
* }*/
// As an experiment going to try matching on the Call-ID. This field seems to be unique and therefore the chance
// of collisions seemingly very slim. As a safeguard if there happen to be two transactions with the same Call-ID in the list the match will not be made.
// One case where the Call-Id match breaks down is for in-Dialogue requests in that case there will be multiple transactions with the same Call-ID and tags.
//if (transaction.TransactionType == SIPTransactionTypesEnum.Invite && transaction.TransactionFinalResponse != null && transaction.TransactionState == SIPTransactionStatesEnum.Completed)
if (transaction.TransactionType == SIPTransactionTypesEnum.Invite && transaction.TransactionFinalResponse != null)
{
if (transaction.TransactionRequest.Header.CallId == sipRequest.Header.CallId &&
transaction.TransactionFinalResponse.Header.To.ToTag == sipRequest.Header.To.ToTag &&
transaction.TransactionFinalResponse.Header.From.FromTag == sipRequest.Header.From.FromTag &&
transaction.TransactionFinalResponse.Header.CSeq == sipRequest.Header.CSeq)
{
//logger.Info("ACK for contact=" + contactAddress + ", cseq=" + sipRequest.Header.CSeq + " was matched by callid, tags and cseq.");
return(transaction);
}
else if (transaction.TransactionRequest.Header.CallId == sipRequest.Header.CallId &&
transaction.TransactionFinalResponse.Header.CSeq == sipRequest.Header.CSeq &&
IsCallIdUniqueForPending(sipRequest.Header.CallId))
{
string requestEndPoint = (sipRequest.RemoteSIPEndPoint != null) ? sipRequest.RemoteSIPEndPoint.ToString() : " ? ";
//logger.Info("ACK for contact=" + contactAddress + ", cseq=" + sipRequest.Header.CSeq + " was matched using Call-ID mechanism (to tags: " + transaction.TransactionFinalResponse.Header.To.ToTag + "=" + sipRequest.Header.To.ToTag + ", from tags:" + transaction.TransactionFinalResponse.Header.From.FromTag + "=" + sipRequest.Header.From.FromTag + ").");
return(transaction);
}
}
}
//logger.Info("ACK for contact=" + contactAddress + ", cseq=" + sipRequest.Header.CSeq + " was not matched.");
}
return(null);
}
}
}
void transaction_TransactionStateChanged(SIPTransaction sipTransaction)
{
Console.WriteLine(sipTransaction.GetType() + " State Change (" + sipTransaction.TransactionId + "): " + sipTransaction.TransactionState);
}
void transaction_TransactionRemoved(SIPTransaction sipTransaction)
{
Console.WriteLine(sipTransaction.GetType() + " Removed (" + sipTransaction.TransactionId + ")");
}
void SetTransactionTraceEvents(SIPTransaction transaction)
{
transaction.TransactionRemoved += new SIPTransactionRemovedDelegate(transaction_TransactionRemoved);
transaction.TransactionStateChanged += new SIPTransactionStateChangeDelegate(transaction_TransactionStateChanged);
transaction.TransactionTraceMessage += new SIPTransactionTraceMessageDelegate(transaction_TransactionTraceMessage);
}
void transaction_TransactionTraceMessage(SIPTransaction sipTransaction, string message)
{
//Console.WriteLine(sipTransaction.GetType() + " Trace (" + sipTransaction.TransactionId + "): " + message);
}
private void UASInviteTransaction_TransactionRequestReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPRequest sipRequest)
{
try
{
if (TransactionState == SIPTransactionStatesEnum.Terminated)
{
logger.Debug("Request received by UASInviteTransaction for a terminated transaction, ignoring.");
}
else if (sipRequest.Method != SIPMethodsEnum.INVITE)
{
logger.Warn("Unexpected " + sipRequest.Method + " passed to UASInviteTransaction.");
}
else
{
if (TransactionState != SIPTransactionStatesEnum.Trying)
{
SIPResponse tryingResponse = GetInfoResponse(m_transactionRequest, SIPResponseStatusCodesEnum.Trying);
SendInformationalResponse(tryingResponse);
}
// Notify new call subscribers.
if (NewCallReceived != null)
{
NewCallReceived(localSIPEndPoint, remoteEndPoint, this, sipRequest);
}
else
{
// Nobody wants the call so return an error response.
SIPResponse declinedResponse = SIPTransport.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Decline, "Nothing listening");
SendFinalResponse(declinedResponse);
}
}
}
catch (Exception excp)
{
logger.Error("Exception UASInviteTransaction GotRequest. " + excp.Message);
}
}
public void RemoveExpiredTransactions()
{
try
{
lock (m_transactions)
{
List <string> expiredTransactionIds = new List <string>();
foreach (SIPTransaction transaction in m_transactions.Values)
{
if (transaction.TransactionType == SIPTransactionTypesEnum.Invite)
{
if (transaction.TransactionState == SIPTransactionStatesEnum.Confirmed)
{
// Need to wait until the transaction timeout period is reached in case any ACK re-transmits are received.
if (DateTime.Now.Subtract(transaction.CompletedAt).TotalMilliseconds >= m_t6)
{
expiredTransactionIds.Add(transaction.TransactionId);
}
}
else if (transaction.TransactionState == SIPTransactionStatesEnum.Completed)
{
if (DateTime.Now.Subtract(transaction.CompletedAt).TotalMilliseconds >= m_t6)
{
expiredTransactionIds.Add(transaction.TransactionId);
}
}
else if (transaction.HasTimedOut)
{
// For INVITES need to give timed out transactions time to send the reliable repsonses and receive the ACKs.
if (DateTime.Now.Subtract(transaction.TimedOutAt).TotalSeconds >= m_t6)
{
expiredTransactionIds.Add(transaction.TransactionId);
}
}
else if (transaction.TransactionState == SIPTransactionStatesEnum.Proceeding)
{
if (DateTime.Now.Subtract(transaction.Created).TotalMilliseconds >= m_maxRingTime)
{
// INVITE requests that have been ringing too long.
transaction.HasTimedOut = true;
transaction.TimedOutAt = DateTime.Now;
transaction.DeliveryPending = false;
transaction.DeliveryFailed = true;
transaction.FireTransactionTimedOut();
}
}
else if (DateTime.Now.Subtract(transaction.Created).TotalMilliseconds >= m_t6)
{
//logger.Debug("INVITE transaction (" + transaction.TransactionId + ") " + transaction.TransactionRequestURI.ToString() + " in " + transaction.TransactionState + " has been alive for " + DateTime.Now.Subtract(transaction.Created).TotalSeconds.ToString("0") + ".");
if (transaction.TransactionState == SIPTransactionStatesEnum.Calling ||
transaction.TransactionState == SIPTransactionStatesEnum.Trying)
{
transaction.HasTimedOut = true;
transaction.TimedOutAt = DateTime.Now;
transaction.DeliveryPending = false;
transaction.DeliveryFailed = true;
transaction.FireTransactionTimedOut();
}
}
}
else if (transaction.HasTimedOut)
{
expiredTransactionIds.Add(transaction.TransactionId);
}
else if (DateTime.Now.Subtract(transaction.Created).TotalMilliseconds >= m_t6)
{
if (transaction.TransactionState == SIPTransactionStatesEnum.Calling ||
transaction.TransactionState == SIPTransactionStatesEnum.Trying ||
transaction.TransactionState == SIPTransactionStatesEnum.Proceeding)
{
//logger.Warn("Timed out transaction in SIPTransactionEngine, should have been timed out in the SIP Transport layer. " + transaction.TransactionRequest.Method + ".");
transaction.DeliveryPending = false;
transaction.DeliveryFailed = true;
transaction.TimedOutAt = DateTime.Now;
transaction.HasTimedOut = true;
transaction.FireTransactionTimedOut();
}
expiredTransactionIds.Add(transaction.TransactionId);
}
}
foreach (string transactionId in expiredTransactionIds)
{
if (m_transactions.ContainsKey(transactionId))
{
SIPTransaction expiredTransaction = m_transactions[transactionId];
expiredTransaction.FireTransactionRemoved();
RemoveTransaction(expiredTransaction);
}
}
}
//PrintPendingTransactions();
}
catch (Exception excp)
{
logger.Error("Exception RemoveExpiredTransaction. " + excp.Message);
}
}
private void UACInviteTransaction_TransactionFinalResponseReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPResponse sipResponse)
{
try
{
// BranchId for 2xx responses needs to be a new one, non-2xx final responses use same one as original request.
if (sipResponse.StatusCode >= 200 && sipResponse.StatusCode < 299)
{
if (_sendOkAckManually == false)
{
Send2xxAckRequest(null, null);
}
}
else
{
// ACK for non 2xx response is part of the INVITE transaction and gets routed to the same endpoint as the INVITE.
var ackRequest = GetInTransactionACKRequest(sipResponse, m_transactionRequest.URI, LocalSIPEndPoint);
base.SendRequest(RemoteEndPoint, ackRequest);
}
if (UACInviteTransactionFinalResponseReceived != null)
{
UACInviteTransactionFinalResponseReceived(localSIPEndPoint, remoteEndPoint, sipTransaction, sipResponse);
}
if (CDR != null)
{
SIPEndPoint localEP = SIPEndPoint.TryParse(sipResponse.Header.ProxyReceivedOn) ?? localSIPEndPoint;
SIPEndPoint remoteEP = SIPEndPoint.TryParse(sipResponse.Header.ProxyReceivedFrom) ?? remoteEndPoint;
CDR.Answered(sipResponse.StatusCode, sipResponse.Status, sipResponse.ReasonPhrase, localEP, remoteEP);
}
}
catch (Exception excp)
{
logger.Error("Exception UACInviteTransaction_TransactionFinalResponseReceived. " + excp.Message);
}
}
private void UASInviteTransaction_TransactionResponseReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPResponse sipResponse)
{
logger.Warn("UASInviteTransaction received unexpected response, " + sipResponse.ReasonPhrase + " from " + remoteEndPoint.ToString() + ", ignoring.");
}
private void UACInviteTransaction_TransactionInformationResponseReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPResponse sipResponse)
{
try
{
if (UACInviteTransactionInformationResponseReceived != null)
{
UACInviteTransactionInformationResponseReceived(localSIPEndPoint, remoteEndPoint, sipTransaction, sipResponse);
}
if (CDR != null)
{
SIPEndPoint localEP = SIPEndPoint.TryParse(sipResponse.Header.ProxyReceivedOn) ?? localSIPEndPoint;
SIPEndPoint remoteEP = SIPEndPoint.TryParse(sipResponse.Header.ProxyReceivedFrom) ?? remoteEndPoint;
CDR.Progress(sipResponse.Status, sipResponse.ReasonPhrase, localEP, remoteEP);
}
}
catch (Exception excp)
{
logger.Error("Exception UACInviteTransaction_TransactionInformationResponseReceived. " + excp.Message);
}
}
private void UACInviteTransaction_TransactionRequestReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPRequest sipRequest)
{
logger.Warn("UACInviteTransaction received unexpected request, " + sipRequest.Method + " from " + remoteEndPoint.ToString() + ", ignoring.");
}
private void SIPCancelTransaction_TransactionRequestReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPRequest sipRequest)
{
try
{
//logger.Debug("CANCEL request received, attempting to locate and cancel transaction.");
//UASInviteTransaction originalTransaction = (UASInviteTransaction)GetTransaction(GetRequestTransactionId(sipRequest.Header.Via.TopViaHeader.Branch, SIPMethodsEnum.INVITE));
SIPResponse cancelResponse;
if (m_originalTransaction != null)
{
//logger.Debug("Transaction found to cancel " + originalTransaction.TransactionId + " type " + originalTransaction.TransactionType + ".");
m_originalTransaction.CancelCall();
cancelResponse = GetCancelResponse(sipRequest, SIPResponseStatusCodesEnum.Ok);
}
else
{
cancelResponse = GetCancelResponse(sipRequest, SIPResponseStatusCodesEnum.CallLegTransactionDoesNotExist);
}
//UpdateTransactionState(SIPTransactionStatesEnum.Completed);
SendFinalResponse(cancelResponse);
}
catch (Exception excp)
{
logger.Error("Exception SIPCancelTransaction GotRequest. " + excp.Message);
}
}
private void SIPCancelTransaction_TransactionFinalResponseReceived(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPTransaction sipTransaction, SIPResponse sipResponse)
{
if (sipResponse.StatusCode < 200)
{
logger.Warn("A SIP CANCEL transaction received an unexpected SIP information response " + sipResponse.ReasonPhrase + ".");
}
else
{
if (CancelTransactionFinalResponseReceived != null)
{
CancelTransactionFinalResponseReceived(localSIPEndPoint, remoteEndPoint, sipTransaction, sipResponse);
}
}
}
private void SIPCancelTransaction_TransactionRemoved(SIPTransaction transaction)
{
// Remove event handlers.
CancelTransactionFinalResponseReceived = null;
}