/************************************************************************
*
* netmasktest.c - Example program to test if an IPv4 address exists 
*              inside of a network, based on a netmask value.
*
* Copyright 2016 Todd Shadburn <tshadburn@opencomputingsolutions.com>
* 
* Licensed under the GNU GPL version 2
* 
************************************************************************/



#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>


int main (int argc, char**argv)
{
	struct in_addr ipaddr;
	struct in_addr network;
	struct in_addr netmask;

	if (argc < 4) {
		fprintf(stderr, "Usage: %s network netmask ipaddr\n", argv[0]);
		exit (2);
	}
	if (inet_aton(argv[1], &network) == 0) {
		fprintf(stderr, "Invalid network address.\n");
		exit (2);
	}
	if (inet_aton(argv[2], &netmask) == 0) {
		fprintf(stderr, "Invalid netmask.\n");
		exit (2);
	}
	if (inet_aton(argv[3], &ipaddr) == 0) {
		fprintf(stderr, "Invalid IP address.\n");
		exit (2);
	}
	fprintf(stderr, "netmask = %x\n", netmask.s_addr);
	
	if ((network.s_addr & netmask.s_addr) == (ipaddr.s_addr & netmask.s_addr))
		fprintf(stdout, "IP address is in network.\n");
	else
		fprintf(stdout, "IP address is not in network.\n");

	return 0;
}