/// <summary>
/// Forces to send all data in buffer to destination host.
/// </summary>
public void Flush()
{
if (m_AvailableInBuffer > 0)
{
m_pSocket.Write(m_Buffer, 0, m_AvailableInBuffer);
m_AvailableInBuffer = 0;
}
}
/// <summary>
/// Sends response to request maker.
/// </summary>
/// <param name="socket">Socket which to use to send response.</param>
/// <param name="remoteEndPoint">Remote end point where to send response.
/// If this value is null, Via header is used to get remote end point.
/// </param>
/// <param name="response">Response to send.</param>
public void SendResponse(SocketEx socket,IPEndPoint remoteEndPoint,SIP_Response response)
{
/* RFC 3581 4. Server Behavior.
When a server attempts to send a response, it examines the topmost
Via header field value of that response. If the "sent-protocol"
component indicates an unreliable unicast transport protocol, such as
UDP, and there is no "maddr" parameter, but there is both a
"received" parameter and an "rport" parameter, the response MUST be
sent to the IP address listed in the "received" parameter, and the
port in the "rport" parameter. The response MUST be sent from the
same address and port that the corresponding request was received on
in order to traverse symmetric NATs.
*/
/* RFC 3261 18.2.2 Sending Responses.
The server transport uses the value of the top Via header field in
order to determine where to send a response. It MUST follow the
following process:
o If the "sent-protocol" is a reliable transport protocol such as
TCP or SCTP, or TLS over those, the response MUST be sent using
the existing connection to the source of the original request
that created the transaction, if that connection is still open.
This requires the server transport to maintain an association
between server transactions and transport connections. If that
connection is no longer open, the server SHOULD open a
connection to the IP address in the "received" parameter, if
present, using the port in the "sent-by" value, or the default
port for that transport, if no port is specified. If that
connection attempt fails, the server SHOULD use the procedures
in [4] for servers in order to determine the IP address and
port to open the connection and send the response to.
o Otherwise, if the Via header field value contains a "maddr"
parameter, the response MUST be forwarded to the address listed
there, using the port indicated in "sent-by", or port 5060 if
none is present. If the address is a multicast address, the
response SHOULD be sent using the TTL indicated in the "ttl"
parameter, or with a TTL of 1 if that parameter is not present.
o Otherwise (for unreliable unicast transports), if the top Via
has a "received" parameter, the response MUST be sent to the
address in the "received" parameter, using the port indicated
in the "sent-by" value, or using port 5060 if none is specified
explicitly. If this fails, for example, elicits an ICMP "port
unreachable" response, the procedures of Section 5 of [4]
SHOULD be used to determine where to send the response.
o Otherwise, if it is not receiver-tagged, the response MUST be
sent to the address indicated by the "sent-by" value, using the
procedures in Section 5 of [4].
*/
// TODO: Probably we can use local endpoint instead of socket. Because then we can
// Search right UDP connection or TCP/TLS connection.
try{
SIP_t_ViaParm via = response.Via.GetTopMostValue();
// End point not specified, get it from Via.
if(remoteEndPoint == null){
string host = null;
int port = 5060;
// Use received host.
if(via.Received != null){
host = via.Received;
}
// Get sent-by host
else{
host = via.SentBy.Split(':')[0];
}
// Use rport if recevived is specified too
if(via.Received != null && via.RPort > 0){
port = via.RPort;
}
// Get port from sent-by
else{
string[] host_port = via.SentBy.Split(':');
if(host_port.Length == 2){
port = Convert.ToInt32(host_port[1]);
}
}
remoteEndPoint = new IPEndPoint(System.Net.Dns.GetHostAddresses(host)[0],port);
}
byte[] data = response.ToByteData();
// Log
m_pSipStack.Logger.AddWrite(data.Length,"Sending (" + data.Length + " bytes): " + socket.LocalEndPoint.ToString() + " -> " + remoteEndPoint.ToString() + "\r\n<begin>\r\n" + System.Text.Encoding.UTF8.GetString(data) + "<end>\r\n");
// We don't have any more that socket what accepted request which response it is.
// There are 2 known cases when no socket:
// 1) Stateless proxy.
// 2) Statefull proxy, but response didn't match any transaction.
if(socket == null){
// UDP Multicast
if(via.ProtocolTransport.ToUpper() == SIP_Transport.UDP && via.Maddr != null){
throw new SIP_TransportException("UDP Multicast not implemented !");
}
// UDP
else if(via.ProtocolTransport.ToUpper() == SIP_Transport.UDP){
foreach(SipListeningPoint listeningPoint in m_pListeningPoints){
if(listeningPoint.Protocol == BindInfoProtocol.UDP){
listeningPoint.Socket.SendTo(data,remoteEndPoint);
return;
}
}
throw new SIP_TransportException("No UDP transport available, this never should happen !");
}
// TCP
else if(via.ProtocolTransport.ToUpper() == SIP_Transport.TCP){
SipTcpPipe pipe = GetTcpPipe(SIP_Transport.TCP,remoteEndPoint);
// Not existing connection, create it.
if(pipe == null){
pipe = new SipTcpPipe(this,remoteEndPoint,true);
}
pipe.SendMessage(data);
}
// TCP TLS
else if(via.ProtocolTransport.ToUpper() == SIP_Transport.TLS){
SipTcpPipe pipe = GetTcpPipe(SIP_Transport.TLS,remoteEndPoint);
// Not existing connection, create it.
if(pipe == null){
pipe = new SipTcpPipe(this,remoteEndPoint,true);
}
pipe.SendMessage(data);
}
}
// We have existing socket, use it.
else{
if(via.ProtocolTransport.ToUpper() == SIP_Transport.UDP){
socket.SendTo(data,remoteEndPoint);
}
else{
socket.Write(data);
}
}
}
catch(Exception x){
throw new SIP_TransportException(x.Message);
}
}