private void NatKeepAliveChannelMessageReceived(SIPChannel sipChannel, SIPEndPoint remoteEndPoint, byte[] buffer)
{
try
{
NATKeepAliveMessage keepAliveMessage = NATKeepAliveMessage.ParseNATKeepAliveMessage(buffer);
if (keepAliveMessage != null)
{
if (keepAliveMessage.LocalSIPEndPoint.Protocol == SIPProtocolsEnum.udp)
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "Relaying NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
m_sipTransport.SendRaw(keepAliveMessage.LocalSIPEndPoint, new SIPEndPoint(keepAliveMessage.RemoteEndPoint), m_sendBuffer);
}
else
{
// For connection oriented protocols check whether a connection exists. NAT keep alives shouldn't cause a connection to be initiated.
SIPChannel sendFromChannel = m_sipTransport.FindSIPChannel(keepAliveMessage.LocalSIPEndPoint);
if (sendFromChannel != null && sendFromChannel.IsConnectionEstablished(keepAliveMessage.RemoteEndPoint))
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "Relaying NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
m_sipTransport.SendRaw(keepAliveMessage.LocalSIPEndPoint, new SIPEndPoint(keepAliveMessage.RemoteEndPoint), m_sendBuffer);
}
else
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "No established connection was found to relay NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
}
}
}
}
catch (Exception excp)
{
logger.Error("Exception NatKeepAliveChannelMessageReceived. " + excp.Message);
}
}
/// <summary>
/// Used to send a request from an internal server agent to an external SIP user agent. The difference between this method and
/// the SendTransparent method is that this one will set Via headers in accordance with RFC3261.
/// </summary>
/// <param name="receivedOnEP">The proxy SIP end point the request was received on.</param>
/// <param name="dstSocket">The SIP end point the request is being sent to.</param>
/// <param name="sipRequest">The SIP request to send.</param>
/// <param name="proxyBranch">The branch parameter for the top Via header that has been pre-calculated by the proxy core.</param>
/// <param name="sendFromSocket">The proxy SIP end point to send this request from. If the SIP request has its ProxySendFrom header
/// value set that will overrule this parameter.</param>
public void SendExternal(SIPEndPoint receivedOnEP, SIPEndPoint dstSIPEndPoint, SIPRequest sipRequest, string proxyBranch, IPAddress publicIPAddress)
{
try
{
if (!IsDestinationValid(sipRequest, dstSIPEndPoint))
{
logger.Debug("SendExternal failed destination check.");
return;
}
// Determine the external SIP endpoint that the proxy will use to send this request.
SIPEndPoint localSIPEndPoint = m_sipTransport.GetDefaultSIPEndPoint(dstSIPEndPoint);
if (!sipRequest.Header.ProxySendFrom.IsNullOrBlank())
{
SIPChannel proxyChannel = m_sipTransport.FindSIPChannel(SIPEndPoint.ParseSIPEndPoint(sipRequest.Header.ProxySendFrom));
if (proxyChannel == null)
{
logger.Warn("No SIP channel could be found for\n" + sipRequest.ToString());
}
localSIPEndPoint = (proxyChannel != null) ? proxyChannel.SIPChannelEndPoint : localSIPEndPoint;
}
if (receivedOnEP != localSIPEndPoint)
{
// The proxy is being requested to send the request on a different socket to the one it was received on.
// A second Via header is added to ensure the response can navigate back the same path. The calculated branch
// parameter needs to go on the top Via header so that whichever internal socket the request is being sent to can
// determine re-transmits.
SIPViaHeader via = new SIPViaHeader(receivedOnEP, CallProperties.CreateBranchId());
sipRequest.Header.Vias.PushViaHeader(via);
SIPViaHeader externalVia = new SIPViaHeader(localSIPEndPoint, proxyBranch);
sipRequest.Header.Vias.PushViaHeader(externalVia);
}
else
{
// Only a single Via header is required as any response to this request will be sent from the same socket it gets received on.
SIPViaHeader via = new SIPViaHeader(localSIPEndPoint, proxyBranch);
sipRequest.Header.Vias.PushViaHeader(via);
}
if (sipRequest.Method != SIPMethodsEnum.REGISTER)
{
AdjustContactHeader(sipRequest.Header, localSIPEndPoint, publicIPAddress);
}
sipRequest.LocalSIPEndPoint = localSIPEndPoint;
// Proxy sepecific headers that don't need to be seen by external UAs.
sipRequest.Header.ProxyReceivedOn = null;
sipRequest.Header.ProxyReceivedFrom = null;
sipRequest.Header.ProxySendFrom = null;
m_sipTransport.SendRequest(dstSIPEndPoint, sipRequest);
}
catch (Exception excp)
{
logger.Error("Exception SIPRequest SendExternal. " + excp.Message);
logger.Error(sipRequest.ToString());
throw;
}
}
