/* Print address, mask, network, and broadcast in binary
 * Copyright 2021 Tj <hacker@iam.tj>
 * Licensed on the terms of the GNU General Public Licence version 3
 *
 * Compile:  gcc -o ipv4_net ipv4_net.c -lm
 * Usage:    ipv4_net  <ipv4address>  <prefix>
 * Example:
 *  ./ipv4_net 10.1.2.5 30
 *  Prefix:         0x0000001e      30
 *  Mask:           0xfffffffc      11111111111111111111111111111100
 *  Address:        0x0a010205      00001010000000010000001000000101        10.1.2.5
 *  Network:        0x0a010204      00001010000000010000001000000100
 *  Broadcast:      0x0a010207      00001010000000010000001000000111
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <arpa/inet.h>

static char * print_binary(unsigned int num, char *buf) {
	int i;
	for(i=31; i >= 0; --i) {
		unsigned int b = (num & ((unsigned int)pow(2, i))) > 0;
		sprintf(&buf[31-i], "%d", b);
	}
	buf[32-i] = '\0';
	return buf;
}

int
main(int argc, char**argv, char **env) {
	unsigned int networkbyteorder = 0;
        unsigned int address = 0;
	unsigned int prefix = atoi(argv[2]);
	unsigned int mask = (unsigned int) ~ (0xffffffffUL >> prefix);
	unsigned int network = 0;
	unsigned int broadcast = 0;
	unsigned char buffer[38];

	inet_pton(AF_INET, argv[1], &networkbyteorder);
	address = ntohl(networkbyteorder);
	network = address & mask;
	broadcast = (0xffffffff >> prefix) | (address & mask);;

	printf("Prefix:\t\t0x%08x\t%d\n", prefix, prefix);
	printf("Mask:\t\t0x%08x\t%s\n", mask, print_binary(mask, buffer));
	printf("Address:\t0x%08x\t%s\t%s\n", address,  print_binary(address, buffer), argv[1]);
	printf("Network:\t0x%08x\t%s\n", network, print_binary(network, buffer));
	printf("Broadcast:\t0x%08x\t%s\n", broadcast, print_binary(broadcast, buffer));

	return 0;
}