cidr_calc.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
# This file is part of GFWList.
#
# Copyright (C) 2018 GFWList Project
# 
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

""" Pretty simple CIDR calculator
Author: Christopher Meng

Usage: ./cidr_calc.py [CIDR1] [CIDR2] ...

Example: ./cidr_calc.py 10.1.0.0/15 192.168.100.0/24
"""

import sys

def usage():
    u = 'Usage:  python cidr_calc.py [CIDR1] [CIDR2] ...\n'
    u += 'Example: ./cidr_calc.py 10.0.0.0/15 192.168.0.0/24'
    print(u)

if sys.version_info[:2] < (3,3):
    raise Exception("Python 3.3 onwards is required!")
elif len(sys.argv) < 2:
    usage()
    sys.exit(0)
else:
    pass

import ipaddress
import itertools

def get_hosts(cidr):
    hosts_list = list(ipaddress.ip_network(cidr).hosts())
    return [str(x) for i, x in enumerate(hosts_list)]

if __name__ == "__main__":
    cidrs = sys.argv[1:]
    try:
        hosts = [get_hosts(i) for i in cidrs]
        merged_hosts = list(itertools.chain(*hosts))
        with open('hosts.txt', 'w') as f:
            for j in merged_hosts:
                f.write(j + '\n')
        f.close()
    except ValueError:
        print('Check if given CIDR is valid.'+'\n'+'Or if the network has host bits set!')