/// <summary>
/// Default constructor.
/// </summary>
/// <param name="stack">Reference to SIP stack.</param>
/// <param name="flow">SIP data flow.</param>
/// <param name="request">Recieved request.</param>
/// <param name="transaction">SIP server transaction which must be used to send response back to request maker.</param>
internal SIP_RequestReceivedEventArgs(SIP_Stack stack, SIP_Flow flow, SIP_Request request, SIP_ServerTransaction transaction)
{
m_pStack = stack;
m_pFlow = flow;
m_pRequest = request;
m_pTransaction = transaction;
}
/// <summary>
/// Default constructor.
/// </summary>
/// <param name="transaction">Server transaction.</param>
/// <param name="response">SIP response.</param>
/// <exception cref="ArgumentNullException">Is raised when any of the arguments is null.</exception>
public SIP_ResponseSentEventArgs(SIP_ServerTransaction transaction, SIP_Response response)
{
if (transaction == null)
{
throw new ArgumentNullException("transaction");
}
if (response == null)
{
throw new ArgumentNullException("response");
}
m_pTransaction = transaction;
m_pResponse = response;
}
/// <summary>
/// Matches SIP request to server transaction. If not matching transaction found, returns null.
/// </summary>
/// <param name="request">SIP request to match.</param>
/// <returns>Returns matching transaction or null if no match.</returns>
internal SIP_ServerTransaction MatchServerTransaction(SIP_Request request)
{
/* RFC 3261 17.2.3 Matching Requests to Server Transactions.
* This matching rule applies to both INVITE and non-INVITE transactions.
*
* 1. the branch parameter in the request is equal to the one in the top Via header
* field of the request that created the transaction, and
*
* 2. the sent-by value in the top Via of the request is equal to the
* one in the request that created the transaction, and
*
* 3. the method of the request matches the one that created the transaction, except
* for ACK, where the method of the request that created the transaction is INVITE.
*
* Internal implementation notes:
* Inernally we use branch + '-' + sent-by for non-CANCEL and for CANCEL
* branch + '-' + sent-by + '-' CANCEL. This is because method matching is actually
* needed for CANCEL only (CANCEL shares cancelable transaction branch ID).
*/
SIP_ServerTransaction retVal = null;
/*
* We use branch and sent-by as indexing key for transaction, the only special what we need to
* do is to handle CANCEL, because it has same branch as transaction to be canceled.
* For avoiding key collision, we add branch + '-' + 'sent-by' + CANCEL for cancel index key.
* ACK has also same branch, but we won't do transaction for ACK, so it isn't problem.
*/
string key = request.Via.GetTopMostValue().Branch + '-' + request.Via.GetTopMostValue().SentBy;
if (request.RequestLine.Method == SIP_Methods.CANCEL)
{
key += "-CANCEL";
}
lock (m_pServerTransactions){
m_pServerTransactions.TryGetValue(key, out retVal);
}
// Don't match ACK for terminated transaction, in that case ACK must be passed to "core".
if (retVal != null && request.RequestLine.Method == SIP_Methods.ACK && retVal.State == SIP_TransactionState.Terminated)
{
retVal = null;
}
return(retVal);
}
/// <summary>
/// Ensures that specified request has matching server transaction. If server transaction doesn't exist,
/// it will be created, otherwise existing transaction will be returned.
/// </summary>
/// <param name="flow">SIP data flow which is used to receive request.</param>
/// <param name="request">SIP request.</param>
/// <returns>Returns matching transaction.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null.</exception>
/// <exception cref="InvalidOperationException">Is raised when request.Method is ACK request.</exception>
public SIP_ServerTransaction EnsureServerTransaction(SIP_Flow flow, SIP_Request request)
{
if (flow == null)
{
throw new ArgumentNullException("flow");
}
if (request == null)
{
throw new ArgumentNullException("request");
}
if (request.RequestLine.Method == SIP_Methods.ACK)
{
throw new InvalidOperationException("ACK request is transaction less request, can't create transaction for it.");
}
/*
* We use branch and sent-by as indexing key for transaction, the only special what we need to
* do is to handle CANCEL, because it has same branch as transaction to be canceled.
* For avoiding key collision, we add branch + '-' + 'sent-by' + CANCEL for cancel index key.
* ACK has also same branch, but we won't do transaction for ACK, so it isn't problem.
*/
string key = request.Via.GetTopMostValue().Branch + '-' + request.Via.GetTopMostValue().SentBy;
if (request.RequestLine.Method == SIP_Methods.CANCEL)
{
key += "-CANCEL";
}
lock (m_pServerTransactions){
SIP_ServerTransaction retVal = null;
m_pServerTransactions.TryGetValue(key, out retVal);
// We don't have transaction, create it.
if (retVal == null)
{
retVal = CreateServerTransaction(flow, request);
}
return(retVal);
}
}
/// <summary>
/// Matches CANCEL requst to SIP server non-CANCEL transaction. Returns null if no match.
/// </summary>
/// <param name="cancelRequest">SIP CANCEL request.</param>
/// <returns>Returns CANCEL matching server transaction or null if no match.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>cancelTransaction</b> is null.</exception>
/// <exception cref="ArgumentException">Is raised when <b>cancelTransaction</b> has invalid.</exception>
public SIP_ServerTransaction MatchCancelToTransaction(SIP_Request cancelRequest)
{
if (cancelRequest == null)
{
throw new ArgumentNullException("cancelRequest");
}
if (cancelRequest.RequestLine.Method != SIP_Methods.CANCEL)
{
throw new ArgumentException("Argument 'cancelRequest' is not SIP CANCEL request.");
}
SIP_ServerTransaction retVal = null;
// NOTE: There we don't add '-CANCEL' because we want to get CANCEL matching transaction, not CANCEL
// transaction itself.
string key = cancelRequest.Via.GetTopMostValue().Branch + '-' + cancelRequest.Via.GetTopMostValue().SentBy;
lock (m_pServerTransactions){
m_pServerTransactions.TryGetValue(key, out retVal);
}
return(retVal);
}
/// <summary>
/// Creates new SIP server transaction for specified request.
/// </summary>
/// <param name="flow">SIP data flow which is used to receive request.</param>
/// <param name="request">SIP request.</param>
/// <returns>Returns added server transaction.</returns>
/// <exception cref="ObjectDisposedException">Is raised when this class is Disposed and this method is accessed.</exception>
/// <exception cref="ArgumentNullException">Is raised when <b>flow</b> or <b>request</b> is null reference.</exception>
public SIP_ServerTransaction CreateServerTransaction(SIP_Flow flow, SIP_Request request)
{
if (m_IsDisposed)
{
throw new ObjectDisposedException(this.GetType().Name);
}
if (flow == null)
{
throw new ArgumentNullException("flow");
}
if (request == null)
{
throw new ArgumentNullException("request");
}
lock (m_pServerTransactions){
SIP_ServerTransaction transaction = new SIP_ServerTransaction(m_pStack, flow, request);
m_pServerTransactions.Add(transaction.Key, transaction);
transaction.StateChanged += new EventHandler(delegate(object s, EventArgs e){
if (transaction.State == SIP_TransactionState.Terminated)
{
lock (m_pClientTransactions){
m_pServerTransactions.Remove(transaction.Key);
}
}
});
SIP_Dialog dialog = MatchDialog(request);
if (dialog != null)
{
dialog.AddTransaction(transaction);
}
return(transaction);
}
}
