cidr-press.py

#!/usr/bin/env python3

# NAME
#   cidr-press - quickly validate a CIDR block without having to think about it
#
# SYNOPSIS
#   cidr-press [--cidr-block CIDR_BLOCK] [--file FILE]

import argparse
import ipaddress
import sys


def main():
    parser = argparse.ArgumentParser(
        description='Validate a CIDR block without thinking about it')
    parser.add_argument('--cidr-block', help='CIDR block you wish to validate')
    parser.add_argument(
        '--file', help='File containing multiple CIDR blocks to validate')

    args = parser.parse_args()
    if args.cidr_block:
        validate_cidr(args.cidr_block)

    if args.file:
        with open(args.file) as f:
            for cidr in f:
                validate_cidr(cidr.rstrip('\n'))

    sys.exit(0)


def validate_cidr(cidr):
    global exit_code
    try:
        ipaddress.ip_network(cidr, strict=True)
    except ValueError:
        print("%s is an invalid CIDR block" % (cidr))
        sys.exit(1)

    network = ipaddress.ip_network(cidr, strict=True)
    if network.is_private:
        print("%s is an RFC1918 (private range) CIDR block" % (cidr))
        sys.exit(1)


if __name__ == '__main__':
    main()