#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <assert.h>
#include <stdint.h>
#include <string.h>

static int parse_cidr(char *string, uint32_t *ip, uint32_t *mask)
{
	char host[128] = "";
	char *bit_str;
	uint32_t bits;

	strncpy(host, string, sizeof(host) - 1);
	bit_str = strchr(host, '/');

	if (!bit_str) {
		return -1;
	}

	*bit_str++ = '\0';
	bits = atoi(bit_str);

	if (bits < 13 || bits > 27) {
		return -2;
	}

	bits = atoi(bit_str);
	inet_pton(AF_INET, host, ip);
	*mask = 0xFFFFFFFF & ~(0xFFFFFFFF << bits);

	return 0;
}

#define test_net(_ip, _net, _mask) ((_net & _mask) == (_ip & _mask))

int main(int argc, char *argv[]) 
{
	int ip, net, mask;
	char net_str[128] = "";
	char mask_str[128] = "";

	if (argc == 3 && strchr(argv[2], '/')) { /* it is cidr notation */
		if (parse_cidr(argv[2], &net, &mask)) {
			fprintf(stderr, "usage: %s <ip> <net>/<bits>\n", argv[0]);
			exit(255);
		}
	} else if (argc < 4) { /* it is net and mask notation */
		fprintf(stderr, "usage: %s <ip> <net> <mask>\n", argv[0]);
		exit(255);
	} else {
		inet_pton(AF_INET, argv[2], &net);
		inet_pton(AF_INET, argv[3], &mask);
	}

	
	inet_pton(AF_INET, argv[1], &ip);
	inet_ntop(AF_INET, &net, net_str, sizeof(net_str) -1);
	inet_ntop(AF_INET, &mask, mask_str, sizeof(mask_str) -1);
	
	printf("ip:\t%s\nnet:\t%s\nmask:\t%s\nmatch:\t%s\n", 
		   argv[1],
		   net_str,
		   mask_str,
		   test_net(ip, net, mask) ? "yes" : "no");

	return 0;
}