//-------------------------------------------------------------------
//	nicread.cpp
//
//	This application opens the '/dev/nic' device-file in order
//	to read and display every packet that the device receives,
//	assuming our driver ('receiver.c') has been installed.
//
//	programmer: ALLAN CRUSE
//	written on: 13 APR 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for read() 

char devname[] = "/dev/nic";	// name of the device special file

int main( int argc, char **argv )
{
	// open the device-file
	int	fd = open( devname, O_RDONLY );
	if ( fd < 0 ) { perror( devname ); exit(1); }

	// loop forever -- or until killed by a signal (e.g., CTRL-C)
	int	count = 0;
	for(;;)	{
		char	buffer[ 2048 ] = {0};
		int	nbytes = read( fd, buffer, sizeof( buffer ) );
		if ( nbytes < 0 ) { perror( "read" ); exit(1); }
		printf( "\npacket #%d (%d bytes)\n", ++count, nbytes );

		if ( nbytes > 64 ) nbytes = 64;	// don't flood the screen
		for (int i = 0; i < nbytes; i+=16)
			{
			printf( "\n%04X: ", i );
			for (int j = 0; j < 16; j++)
				{
				unsigned char	ch = buffer[i+j];
				if ( i+j < nbytes ) printf( "%02X ", ch );
				else	printf( "   " );
				}
			for (int j = 0; j < 16; j++)
				{
				char	ch = buffer[i+j];
				if (( ch < 0x20 )||( ch > 0x7E )) ch = '.';
				if ( i+j < nbytes ) printf( "%c", ch );
				else	printf( " " );
				}
			}
		printf( "\n\n" );		
		}
}