etherinputdemo.c

vxworks 下的网络程序源码 包括

/* etherInputDemo.c - Demo for using low-level ethernet input routines */
 
 /* Copyright 1984-1997 Wind River Systems, Inc. */
 
 /*
 modification history
 --------------------
 01e,06nov97,mm   added copyright.
 01d,22Sep97,mm   removed include <vxWorks.h> changed include "etherDemo.h" to 
 		 "in_etherDemo.h"
 01c,22Sep97,mm   added include<etherLib.h> ,<string.h> ,<stdio.h> and <errno.h>
 01b,22Sep97,mm   changed "if.h" to "net/if.h"
 01a,16Feb94,ms   modified and cleaned up for VxDemo.
 */
 
 #include <etherLib.h> 
 #include <string.h>
 #include <stdio.h>
 #include <errno.h>  
 #include "net/if.h"
 #include "netinet/if_ether.h"
 #include "in_etherDemo.h"
 
 /*****************************************************************************
  * etherInputDemo - Demo for using low-level ethernet input routines
  *
  * DESCRIPTION
  *
  *     Handles (receives) raw input frames (input data) from the network
  *     interface using ether input hook routine etHandle.
  *
  *     This is a simple demonstration of using low-level input ethernet 
  *     routines. The other half of the demonstration of using low-level
  *     output ethernet routines is in etherOutputDemo.c. etherInputDemo runs on
  *     one VxWorks system, and etherOutputDemo runs on an other VxWorks system
  *     in the same physical network.
  *
  * RETURNS: OK or ERROR
  * 
  * EXAMPLE:
  *
  *     To run this etherInputDemo task from the VxWorks shell do as follows: 
  *     -> sp (etherInputDemo)
  *
  */
 
 STATUS etherInputDemo ()
     {
     if (etherInputHookAdd (etHandle) == OK)
 	printf ("etherInputHookAdd successful\n");
     else  
 	{
         perror ("etherInputHook failed");
         return (ERROR);
         }
 
     return (OK);
     }
 
 
 /*****************************************************************************
  * etHandle - ether input hook routine for handling raw input frames from the
  *            network interface. This routine is executed at task level 
  *            interrupt service for input packets.
  *
  * RETURNS: TRUE or FALSE
  * 
  */
 
 BOOL etHandle (ifp, buffer, length)
     struct ifnet	*ifp;
     char		*buffer;
     int			length;
 
     {
     struct ether_header		*ethHdr;
     char 			*buffPtr;
     int 			ix;
     char                        tmp[25];
 
     ethHdr = (struct ether_header *) buffer;
     if (ntohs(ethHdr->ether_type) != (u_short) ET_TYPE)
 	return (FALSE); /* Not a user defined protocol type, hence 0 is passed
                      * to indicate further processing of data to be handled by 
                      * higher level protocols (IP, TCP etc., ).
                      */
 
 
     /* Handle raw input frames. 
      * Data integrity check and printing the input message is done for 
      * demonstration purpose.
      */
 
     /* Check for data integrity error */
     buffPtr = (char *) (buffer + sizeof (*ethHdr));
     strncpy (tmp, buffPtr, strlen (etMessage));
     for (ix = 0; ix < sizeof (etMessage); ++ix)
 	if (*buffPtr++ != etMessage [ix])
 	    break;
     if (ix != strlen (etMessage))
         {
 	logMsg ("etHandle: data integrity error at %d.\n", ix);
 	return (ERROR);
 	}
 
     logMsg ("etHandle: data okay - message is : %s \n", tmp);
 
     return (TRUE); /* non-zero value to imply hook routine has processed
                     * the input and there is no need for further handling by
                     * any higher level protocols (IP, TCP etc.) 
                     */
     }