censored_subnets_Ukraine.py

import json
import urllib2
import re

"""
This script prints up-to-date list of blocked subnets in Ukraine. This output may be used
in a shell script on router to selectively route all traffic to blocked resources through
your VPN.

GATEWAY="10.0.1.1"
for route in `python censored_subnets.py`; do
  ip route replace ${route} via ${GATEWAY} 1>/dev/null 2>&1
done
Gist: https://gist.github.com/Dmitriusan/eeff54351ab7bae8d35da8c1f500b5dc
"""


def curl(url):
    return urllib2.urlopen(url).read()

regex = re.compile(r'^[\d./]+$', flags=re.MULTILINE)


def validate(subnet):
    """
    Checks that subnet declaration consists only of digits, dots and slashes in order to avoid shell injection
     that is theoretically possible if UaBlacklist.net site is compromised
    """
    return regex.match(subnet) is not None


def get_nets():
    request = "https://uablacklist.net/subnets.json"
    responce = curl(request)
    return [subnet for subnet in json.loads(responce) if validate(subnet)]

if __name__ == "__main__":
    nets = get_nets()
    for net in nets:
        print net