/*
 * randmac.c v1.2 Final
 * I)ruid <druid@caughq.org>
 *
 * This little tool generates a random MAC address and sets the
 * specified interface to that MAC address (defaults to eth0
 * if no interface is specified).
 *
 * You should not use this tool.  Instead you should use macchanger,
 * as it has many more useful features:
 * 
 *   http://www.alobbs.com/modules.php?op=modload&name=macc&file=index
 *
 * Or, if you happen to use Windows, Technitium's tool is good:
 *
 *   http://tmac.technitium.com/tmac/index.html
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define IFCONFIG "/sbin/ifconfig"


int main( int argc, char *argv[] ) {
	int x, ret = 0;
	char *interface;
	char *command;
	char vendor[9];
	int val[6];

	/* Determine interface */
	if( argc <= 1 ) {
		printf( "No interface specified, defaulting to eth0\n" );
		interface = malloc( strlen("eth0")+1 );
		sprintf( interface, "%s", "eth0");
	} else {
		interface = argv[1];
		printf( "Setting MAC for interface %s\n", interface );
	}

	/* Seed rand() function */
	sleep(1);
	srand(time(NULL));

	/* Randomly Choose a Vendor */
	switch( rand() % 10 ) {
		case 0:
			sprintf( vendor, "00:e0:f9" ); /* Cisco Systems */
			break;
		case 1:
			sprintf( vendor, "00:00:d8" ); /* Novell */
			break;
		case 2:
			sprintf( vendor, "00:00:36" ); /* Atari */
			break;
		case 3:
			sprintf( vendor, "00:00:3D" ); /* Unisys */
			break;
		case 4:
			sprintf( vendor, "00:00:75" ); /* Nortel Networks */
			break;
		case 5:
			sprintf( vendor, "08:00:20" ); /* SUN Microsystems */
			break;
		case 6:
			sprintf( vendor, "00:00:d9" ); /* Nippon Telegraph & Telephone */
			break;
		case 7:
			sprintf( vendor, "00:03:93" ); /* Apple Computer */
			break;
		case 8:
			sprintf( vendor, "10:00:5a" ); /* IBM */
			break;
		case 9:
			sprintf( vendor, "00:d0:c6" ); /* Thomas & Betts */
			break;
		default:
			sprintf( vendor, "08:00:07" ); /* Apple Computer */
			break;
	}

	/* Choose Randomized Bits */
	for( x = 0; x < 6; x++ ) {
		val[x] = rand() % 16;
	}	

	/* Build command string */	
	command = malloc( strlen("IFCONFIG") + strlen(interface) + strlen(" hw ether ") + strlen(vendor) + 9 + 2 );
	sprintf( command, "%s %s hw ether %s:%x%x:%x%x:%x%x\n", \
		IFCONFIG, interface, vendor, \
		val[0], val[1], val[2], val[3], val[4], val[5] );

	/* Execute command */
	printf( "Executing: %s", command );
	ret = system(command);

	/* Exit with return value from command */
	exit(ret);
}