tcp_server_demo.c

用于以太网开发

/*
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 *
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/** \file tcp_server_demo.c
 *	\ingroup opentcp_example
 *	\brief Demonstration of a possible scenario of writing TCP applications
 *	\author 
 *		\li Vladan Jovanovic ([e-mail])
 *	\version 1.0
 *	\date 10.10.2002
 *	\bug
 *	\warning
 *		\li This example is given for demonstration purposes only. It
 *		was not tested for correct operation.
 *	\todo
 *  
 *	Blank TCP demo application showing TCP functions and how applications
 *	might use them. Please note that this is an example for a TCP server
 *	application - the kind of application that waits for a connection and
 *	does not initiate connection establishment towards other hosts. 
 */
#include <inet/debug.h>
#include <inet/datatypes.h>
#include <inet/globalvariables.h>
#include <inet/system.h>
#include <inet/tcp_ip.h>



/* The applications that use TCP must implement following function stubs			*/
/* void application_name_init (void) - call once when processor starts				*/
/* void application_name_run (void) - call periodically on main loop				*/
/* INT32 application_name_eventlistener (INT8, UINT8, UINT32, UINT32)				*/
/* - called by TCP input process to inform arriving data, errors etc */

/* These will probably go to some include file */
void tcps_demo_init(void);
void tcps_demo_run(void);
INT32 tcps_demo_eventlistener(INT8 , UINT8 , UINT32 , UINT32 );

/** \brief Socket handle holder for this application
 *
 * This variable holds the assigned socket handle. Note that this application 
 * will reserve one TCP socket immediately and will not release it. For
 * saving resources, TCP sockets can also be allocated/deallocated 
 * dynamically.
 */
INT8 tcps_demo_soch;

UINT8 tcps_demo_senddata; /**< Used to trigger data sending */

#define TCPS_DEMO_PORT	5001 /**< Port number on which we'll be listening for incoming connections */

/* Internal function used for sending data to a predefined host */
INT16 tcps_demo_send(void);

/* Initialize resources needed for the TCP server application */
void tcps_demo_init(void)
{
	
	DEBUGOUT("Initializing TCP server application. \r\n");
		
	/* Get socket:
	 * 	TCP_TYPE_SERVER - type of TCP socket is server
	 * 	TCP_TOS_NORMAL  - no other type of service implemented so far
	 *	TCP_DEF_TOUT	- timeout value in seconds. If for this many seconds
	 *		no data is exchanged over the TCP connection the socket will be
	 *		closed.
	 *	tcps_demo_eventlistener - pointer to event listener function for
	 * 		this socket.	
	 */

	tcps_demo_soch = tcp_getsocket(TCP_TYPE_SERVER, TCP_TOS_NORMAL, TCP_DEF_TOUT, tcps_demo_eventlistener);
	
	if( tcps_demo_soch < 0 )
	{
		DEBUGOUT("TCP server unable to get socket. Resetting!!!\r\n");
		RESET_SYSTEM();
	}
	
	/* Put it to listen on some port	*/
	tcp_listen(tcps_demo_soch,TCPS_DEMO_PORT);
	
	/* for now no data sending */
	tcps_demo_senddata=0;
}

void tcps_demo_run(void)
{
	
	UINT8	i;
	
	/* do maybe some other TCP server app stuff
	 * .....
	 */
	
	if(tcps_demo_senddata){
		if(tcps_demo_send()!=-1)		
			tcps_demo_senddata=0;
	}
}

 /*
 * Event listener invoked when TCP/IP stack receives TCP data for
 * a given socket. Parameters:
 * - cbhandle - handle of the socket this packet is intended for. Check it
 *	just to be sure, but in general case not needed
 * - event - event that is notified. For TCP there are quite a few possible
 *	events, check switch structure below for more information
 * - par1, par2 - parameters who's use depends on the event that is notified
 */
INT32 tcps_demo_eventlistener(INT8 cbhandle, UINT8 event, UINT32 par1, UINT32 par2)
{
/* This function is called by TCP stack to inform about events	*/
	UINT16 i;
	
	if( cbhandle != tcps_demo_soch)		/* Not our handle	*/
		return(-1);
	
	switch( event ){
		
		/* Connection request event. Used by TCP/IP stack to inform
		 * the application someone is trying to establish a connection.
		 * Server can decide, based on provided IP address and port number,
		 * whether to allow or not connection establishment.
		 * Parameters:
		 *  - par1 - remote hosts IP address
		 *  - par2 - remote hosts port number
		 * 
		 * Return values from event listener:
		 * -1 - do not allow connection to be established (send reset)
		 * -2 - do not send any response for now to the SYN packet (let's
		 *		think a little before answering)
		 * 1  - allow connection to be established
		 */
		case TCP_EVENT_CONREQ:
			DEBUGOUT("Connection request arrived!\r\n");
			
			/* Enable all connections	*/
			return(1);
		
			break;
			
		/* Connection abort event. Connection on a given socket is beeing 
		 * aborted for somereason (usually retransmissions are used up or 
		 * some abnormal situation in communication happened).
 		 * Parameters:
		 *  - par1 - remote hosts IP address
		 *  - par2 - remote hosts port number
		 */
		case TCP_EVENT_ABORT:
			DEBUGOUT("Connection aborting!\r\n");
			break;
		
		/* Connection established event - three-way handshaking performed
		 * OK and connection is established.
		 * Parameters:
		 *  - par1 - remote hosts IP address
		 *  - par2 - remote hosts port number
		 */
		case TCP_EVENT_CONNECTED:
			DEBUGOUT("TCP connection established!\r\n");
		
			break;
			
		/* Connection closing event. Happens when TCP connection is
		 * intentionally close by some side calling close function and
		 * initializing proper TCP connection close procedure.
		 * Parameters:
		 *  - par1 - remote hosts IP address
		 *  - par2 - remote hosts port number
		 */
		case TCP_EVENT_CLOSE:
			DEBUGOUT("TCP Connection closing...!\r\n");
			break;
			
		/* Data acknowledgment event. Happens when data that was
		 * previously sent gets acknowledged. This means we can now
		 * send some more data! :-)
		 * Parameters:
		 *  - par1 - remote hosts IP address
		 *  - par2 - remote hosts port number
		 */
		case TCP_EVENT_ACK:
			DEBUGOUT("Data acknowledged!\r\n");
			/* if more data should be sent, adjust variables and
				set tcps_demo_senddata variable */
				
			break;
		
		/* Data received event. Happens when we receive some data over the
		 * TCP connection.
		 * Parameters:
		 *  - par1 - number of data bytes received
		 *  - par2 = 0
		 */
		case TCP_EVENT_DATA:
			DEBUGOUT("Data arrived!\r\n");
			/* read data that was received (and 
			 * probably do something with it :-)
			 */
			for(i=0;i<par1;i++)
				RECEIVE_NETWORK_B();
				
			/* If needed initialize data sending
			 * by setting tcps_demo_senddata variable
			 */
			break;
			
		/* Regenerate data event. Happens when data needs to be
		 * retransmitted because of possible loss on the network.
		 * Note that THE SAME DATA must be sent over and over again
		 * until TCP_EVENT_ACK is generated (for that data)! 
		 * Parameters:
		 *  - par1 - amount of data to regenerate (usually all)
		 *	- par2 = 0
		 */
		case TCP_EVENT_REGENERATE:
			tcps_demo_send();
			break;
	
	
		default:
			return(-1);
	}
}

INT16 tcps_demo_send(void){
	UINT16 i;
	/* first check if data sending is possible (it may be that
	 * previously sent data is not yet acknowledged)
	 */
	if(tcp_checksend(tcps_demo_soch) < 0 ){
		/* Not yet */
		return -1;
	}
	
	/* put message in buffer. Message needs to start from TCP_APP_OFFSET
 	 * because TCP/IP stack will put headers in front of the message to
 	 * avoid data copying
 	 */
	for(i=0;i<32;i++)
		net_buf[TCP_APP_OFFSET+i]='A'+(i%25);

	/* send data */
	return tcp_send(tcps_demo_soch, &net_buf[TCP_APP_OFFSET], NETWORK_TX_BUFFER_SIZE - TCP_APP_OFFSET, 32);

}