/// <summary>
/// Forwards a SIP request through the Proxy. This method differs from the standard Send in that irrespective of whether the Proxy is
/// receiving and sending on different sockets only a single Via header will ever be allowed on the request. It is then up to the
/// response processing logic to determine from which Proxy socket to forward the request and to add back on the Via header for the
/// end agent. This method is only ever used for requests destined for EXTERNAL SIP end points.
/// </summary>
/// <param name="dstSIPEndPoint">The destination SIP socket to send the request to.</param>
/// <param name="sipRequest">The SIP request to send.</param>
/// default channel that matches the destination end point should be used.</param>
public void SendTransparent(SIPEndPoint dstSIPEndPoint, SIPRequest sipRequest, IPAddress publicIPAddress)
{
try
{
if (!IsDestinationValid(sipRequest, dstSIPEndPoint))
{
logger.Debug("SendTransparent failed destination check.");
return;
}
// Determine the external SIP endpoint that the proxy will use to send this request.
SIPEndPoint localSIPEndPoint = null;
if (!sipRequest.Header.ProxySendFrom.IsNullOrBlank())
{
SIPChannel proxyChannel = m_sipTransport.FindSIPChannel(SIPEndPoint.ParseSIPEndPoint(sipRequest.Header.ProxySendFrom));
localSIPEndPoint = (proxyChannel != null) ? proxyChannel.SIPChannelEndPoint : null;
}
localSIPEndPoint = localSIPEndPoint ?? m_sipTransport.GetDefaultSIPEndPoint(dstSIPEndPoint);
// Create the single Via header for the outgoing request. It uses the passed in branchid which has been taken from the
// request that's being forwarded. If this proxy is behind a NAT and the public IP is known that's also set on the Via.
string proxyBranch = sipRequest.Header.Vias.PopTopViaHeader().Branch;
sipRequest.Header.Vias = new SIPViaSet();
SIPViaHeader via = new SIPViaHeader(localSIPEndPoint, proxyBranch);
if (publicIPAddress != null)
{
via.Host = publicIPAddress.ToString();
}
sipRequest.Header.Vias.PushViaHeader(via);
if (sipRequest.Method != SIPMethodsEnum.REGISTER)
{
AdjustContactHeader(sipRequest.Header, localSIPEndPoint, publicIPAddress);
}
// If dispatcher is being used record the transaction so responses are sent to the correct internal socket.
if (m_dispatcher != null && sipRequest.Method != SIPMethodsEnum.REGISTER && sipRequest.Method != SIPMethodsEnum.ACK && sipRequest.Method != SIPMethodsEnum.NOTIFY)
{
//Log("RecordDispatch for " + sipRequest.Method + " " + sipRequest.URI.ToString() + " to " + sipRequest.RemoteSIPEndPoint.ToString() + ".");
m_dispatcher.RecordDispatch(sipRequest, sipRequest.RemoteSIPEndPoint);
}
// 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;
sipRequest.LocalSIPEndPoint = localSIPEndPoint;
m_sipTransport.SendRequest(dstSIPEndPoint, sipRequest);
}
catch (Exception excp)
{
logger.Error("Exception SendTransparent. " + excp.Message);
logger.Error(sipRequest.ToString());
throw;
}
}