NF_EventHandler
===================

The client application must implement this interface and pass the object pointer to nf_init function. 
nfapi code calls the methods of NF_EventHandler from separate thread(s) to indicate the extension notifications. 
The interface is defined as an abstract class with pure virtual functions for C++. 
If the symbol _C_API is defined, the interface is a structure with function pointers.

*C++ (_C_API is not defined)*

.. code-block::

	class NF_EventHandler
	{
	public:
		virtual void threadStart() = 0;
		virtual void threadEnd() = 0;
	
		//
		// TCP events
		//
		virtual void tcpConnectRequest(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo) = 0;
		virtual void tcpConnected(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo) = 0;
		virtual void tcpClosed(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo) = 0;
		virtual void tcpReceive(ENDPOINT_ID id, const char * buf, int len) = 0;
		virtual void tcpSend(ENDPOINT_ID id, const char * buf, int len) = 0;
		virtual void tcpCanReceive(ENDPOINT_ID id) = 0;
		virtual void tcpCanSend(ENDPOINT_ID id) = 0;

		//
		// UDP events
		//
		virtual void udpCreated(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo) = 0;
		virtual void udpConnectRequest(ENDPOINT_ID id, PNF_UDP_CONN_REQUEST pConnReq) = 0;
		virtual void udpClosed(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo) = 0;
		virtual void udpReceive(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options) = 0;
		virtual void udpSend(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options) = 0;
		virtual void udpCanReceive(ENDPOINT_ID id) = 0;
		virtual void udpCanSend(ENDPOINT_ID id) = 0;
	};

*C (_C_API is defined)*

.. code-block::

	typedef struct _NF_EventHandler
	{
		void (NFAPI_CC *threadStart)();
	 	void (NFAPI_CC *threadEnd)();
	
		 //
		 // TCP events
		 //
		 void (NFAPI_CC *tcpConnectRequest)(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo);
		 void (NFAPI_CC *tcpConnected)(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo);
		 void (NFAPI_CC *tcpClosed)(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo);
		 void (NFAPI_CC *tcpReceive)(ENDPOINT_ID id, const char * buf, int len);
		 void (NFAPI_CC *tcpSend)(ENDPOINT_ID id, const char * buf, int len);
		 void (NFAPI_CC *tcpCanReceive)(ENDPOINT_ID id);
		 void (NFAPI_CC *tcpCanSend)(ENDPOINT_ID id);

		 //
		 // UDP events
		 //
		 void (NFAPI_CC *udpCreated)(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo);
		 void (NFAPI_CC *udpConnectRequest)(ENDPOINT_ID id, PNF_UDP_CONN_REQUEST pConnReq);
		 void (NFAPI_CC *udpClosed)(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo);
		 void (NFAPI_CC *udpReceive)(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options);
		 void (NFAPI_CC *udpSend)(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options);
		 void (NFAPI_CC *udpCanReceive)(ENDPOINT_ID id);
		 void (NFAPI_CC *udpCanSend)(ENDPOINT_ID id);
	} NF_EventHandler, *PNF_EventHandler;

.. cpp:function:: void threadStart()

	Called immediately after starting the filtering thread. Use this event for thread-specific initialization, e.g. calling CoInitialize() etc.

.. cpp:function:: void threadEnd()
	
	Called before stopping the thread.

.. cpp:function:: void tcpConnectRequest(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo)

	:param id: Connection identifier.
	:param pConnInfo: Connection parameters, see :doc:`ref_NF_TCP_CONN_INFO`.
	
	Called before establishing an outgoing TCP connection, when NF_INDICATE_CONNECT_REQUESTS flag is enabled in an appropriate rule. 
	It is possible to modify the fields filteringFlag and remoteAddress in pConnInfo structure. 
	The changes are applied to the connection. 

.. cpp:function:: void tcpConnected(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo)

	:param id: Connection identifier.
	:param pConnInfo: Connection parameters, see :doc:`ref_NF_TCP_CONN_INFO`.

	Called after establishing incoming or outgoing TCP connection.

.. cpp:function:: void tcpClosed(ENDPOINT_ID id, PNF_TCP_CONN_INFO pConnInfo)

	:param id: Connection identifier.
	:param pConnInfo: Connection parameters, see :doc:`ref_NF_TCP_CONN_INFO`.
	
	Called after closing a TCP connection.

.. cpp:function:: void tcpReceive(ENDPOINT_ID id, const char * buf, int len)

	:param id: Connection identifier.
	:param buf: Pointer to data buffer.
	:param len: Buffer length

	Indicates the buffer received from server.

.. cpp:function:: void tcpSend(ENDPOINT_ID id, const char * buf, int len)
	
	:param id: Connection identifier.
	:param buf: Pointer to data buffer.
	:param len: Buffer length

	Indicates the buffer sent from a local socket.


.. cpp:function:: void tcpCanReceive(ENDPOINT_ID id)

	:param id: Connection identifier.

	Notifies that the internal buffer for inbound packets is empty and it is possible to call nf_tcpPostReceive for pushing receives via specified connection.

.. cpp:function:: void tcpCanSend(ENDPOINT_ID id)

	:param id: Connection identifier.

	Notifies that the internal buffer for outbound packets is empty and it is possible to call nf_tcpPostSend for pushing sends via specified connection.

.. cpp:function:: void udpCreated(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo)

	:param id: Socket identifier.
	:param pConnInfo: Socket parameters, see :doc:`ref_NF_UDP_CONN_INFO`.

	Called after creating UDP socket.

.. cpp:function:: void udpConnectRequest(ENDPOINT_ID id, PNF_UDP_CONN_REQUEST pConnReq)
	
	Not used.

.. cpp:function:: void udpClosed(ENDPOINT_ID id, PNF_UDP_CONN_INFO pConnInfo)

	:param id: Socket identifier.
	:param pConnInfo: Socket parameters, see :doc:`ref_NF_UDP_CONN_INFO`.

	Called after closing a socket.

.. cpp:function:: void udpReceive(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options)

	:param id: Socket identifier.
	:param remoteAddress: Source address.
	:param buf: Pointer to data buffer.
	:param len: Buffer length.
	:param options: Pointer to :doc:`ref_NF_UDP_OPTIONS`.

	Indicates the buffer received from server.

.. cpp:function:: void udpSend(ENDPOINT_ID id, const unsigned char * remoteAddress, const char * buf, int len, PNF_UDP_OPTIONS options)

	:param id: Socket identifier.
	:param remoteAddress: Source address.
	:param buf: Pointer to data buffer.
	:param len: Buffer length.
	:param options: Pointer to :doc:`ref_NF_UDP_OPTIONS`.

	Indicates the buffer sent from a local socket.

.. cpp:function:: void udpCanReceive(ENDPOINT_ID id)

	:param id: Socket identifier.

	Notifies that the internal buffer for inbound packets is empty, and it is possible to call nf_udpPostReceive for indicating receives via specified socket.

.. cpp:function:: void udpCanSend(ENDPOINT_ID id)

	:param id: Socket identifier.

	Notifies that the internal buffer for outbound packets is empty, and it is possible to call nf_udpPostSend for indicating sends via specified socket.