/// <summary>
/// Sends in initial notification request for a new subscription where it makes sense to do so.
/// </summary>
/// <param name="subscribeRequest">The client request that resulted in the subscription creation.</param>
/// <param name="sipAccount">The authenticated SIP account that created the subscription.</param>
private void SendInitialNotification(SIPRequest subscribeRequest, ISIPAccount sipAccount)
{
if (SIPEventPackageType.IsValid(subscribeRequest.Header.Event))
{
var eventPackage = SIPEventPackageType.Parse(subscribeRequest.Header.Event);
if (eventPackage == SIPEventPackagesEnum.MessageSummary)
{
// Send a dummy message waiting indicator message so that a client can verify a notification request can
// be received.
var dstUri = subscribeRequest.Header.Contact[0].ContactURI;
var accountURI = new SIPURI(sipAccount.SIPUsername, sipAccount.SIPDomain, null, dstUri.Scheme, dstUri.Protocol);
var notifyReq = SIPRequest.GetRequest(SIPMethodsEnum.NOTIFY,
subscribeRequest.Header.Contact[0].ContactURI,
new SIPToHeader(null, accountURI.CopyOf(), CallProperties.CreateNewTag()),
new SIPFromHeader(null, accountURI.CopyOf(), CallProperties.CreateNewTag()));
notifyReq.Header.CallId = subscribeRequest.Header.CallId;
notifyReq.Header.CSeq = subscribeRequest.Header.CSeq++;
notifyReq.Header.Server = m_serverAgent;
notifyReq.Header.Event = SIPEventPackageType.MESSAGE_SUMMARY_EVENT_VALUE;
notifyReq.Header.SubscriptionState = "active";
notifyReq.Header.SetDateHeader();
notifyReq.Header.ContentType = SIPMIMETypes.MWI_CONTENT_TYPE;
notifyReq.Body = "Messages-Waiting: no";
// A little trick here is using the remote SIP end point as the destination rather than the Contact URI.
// Ideally some extra logic to check for IPv4 NAT should be applied. But since this server is known to
// be operating in the cloud and only send NOTIFY requests to Internet clients it should be a reasonable
// option.
SIPNonInviteTransaction notifyTx = new SIPNonInviteTransaction(m_sipTransport, notifyReq, subscribeRequest.RemoteSIPEndPoint);
notifyTx.SendRequest();
}
}
}
/// <summary>
/// This method handles incoming requests from the SIP transport instance. It may be working in
/// conjunction with other receivers on the same SIP transport so it should filter the requests
/// to identify the NOTIFY requests for this subscription.
/// </summary>
/// <param name="localSIPEndPoint">The local SIP end point the request was received on.</param>
/// <param name="remoteEndPoint">The remote SIP end point the request was received from.</param>
/// <param name="sipRequest">The SIP request.</param>
private async Task GotNotificationRequest(SIPEndPoint localSIPEndPoint, SIPEndPoint remoteEndPoint, SIPRequest sipRequest)
{
if (sipRequest.Method == SIPMethodsEnum.NOTIFY && sipRequest.Header.CallId == m_subscribeCallID &&
SIPEventPackageType.Parse(sipRequest.Header.Event) == m_sipEventPackage && sipRequest.Body != null)
{
logger.LogDebug($"SIPNotifierClient GotNotificationRequest for {sipRequest.Method} {sipRequest.URI} {sipRequest.Header.CSeq}.");
SIPResponse okResponse = SIPResponse.GetResponse(sipRequest, SIPResponseStatusCodesEnum.Ok, null);
await m_sipTransport.SendResponseAsync(okResponse).ConfigureAwait(false);
if (sipRequest.Header.CSeq <= m_remoteCSeq)
{
logger.LogWarning($"A duplicate NOTIFY request received by SIPNotifierClient for subscription Call-ID {m_subscribeCallID}.");
}
else
{
//logger.LogDebug("New dialog info notification request received.");
m_remoteCSeq = sipRequest.Header.CSeq;
NotificationReceived?.Invoke(m_sipEventPackage, sipRequest.Body);
}
}
}
/// <summary>
/// Initiates a SUBSCRIBE request to a notification server.
/// </summary>
/// <param name="subscribeURI">The SIP user that dialog notifications are being subscribed to.</param>
public void Subscribe(SIPURI subscribeURI, int expiry, SIPEventPackagesEnum sipEventPackage, string subscribeCallID, SIPURI contactURI)
{
try
{
if (m_attempts >= MAX_SUBSCRIBE_ATTEMPTS)
{
logger.LogWarning($"Subscription to {subscribeURI} reached the maximum number of allowed attempts without a failure condition.");
m_subscribed = false;
SubscriptionFailed?.Invoke(subscribeURI, SIPResponseStatusCodesEnum.InternalServerError, "Subscription reached the maximum number of allowed attempts.");
m_waitForSubscribeResponse.Set();
}
else
{
m_attempts++;
m_localCSeq++;
SIPRequest subscribeRequest = SIPRequest.GetRequest(
SIPMethodsEnum.SUBSCRIBE,
m_resourceURI,
new SIPToHeader(null, subscribeURI, m_subscriptionToTag),
new SIPFromHeader(null, new SIPURI(m_authUsername, m_authDomain, null, m_resourceURI.Scheme, SIPProtocolsEnum.udp), m_subscriptionFromTag));
if (contactURI != null)
{
subscribeRequest.Header.Contact = new List <SIPContactHeader>()
{
new SIPContactHeader(null, contactURI)
};
}
else
{
subscribeRequest.Header.Contact = new List <SIPContactHeader>()
{
SIPContactHeader.GetDefaultSIPContactHeader(subscribeRequest.URI.Scheme)
};
}
subscribeRequest.Header.CSeq = m_localCSeq;
subscribeRequest.Header.Expires = expiry;
subscribeRequest.Header.Event = SIPEventPackageType.GetEventHeader(sipEventPackage);
subscribeRequest.Header.CallId = subscribeCallID;
if (!m_filter.IsNullOrBlank())
{
subscribeRequest.Body = m_filter;
subscribeRequest.Header.ContentLength = m_filter.Length;
subscribeRequest.Header.ContentType = m_filterTextType;
}
SIPNonInviteTransaction subscribeTransaction = new SIPNonInviteTransaction(m_sipTransport, subscribeRequest, m_outboundProxy);
subscribeTransaction.NonInviteTransactionFinalResponseReceived += SubscribeTransactionFinalResponseReceived;
subscribeTransaction.NonInviteTransactionFailed += SubscribeTransactionFailed;
LastSubscribeAttempt = DateTime.Now;
subscribeTransaction.SendRequest();
}
}
catch (Exception excp)
{
logger.LogError("Exception SIPNotifierClient Subscribe. " + excp.Message);
SubscriptionFailed?.Invoke(m_resourceURI, SIPResponseStatusCodesEnum.InternalServerError, "Exception Subscribing. " + excp.Message);
m_waitForSubscribeResponse.Set();
}
}
