Simple script that gets all CloudFront CIDRs and prints them out as OpenVPN routes

cidrs-to-ovpn.py

import urllib.request
import json
import socket
import struct

def cidr_to_netmask(cidr):
  network, net_bits = cidr.split('/')
  host_bits = 32 - int(net_bits)
  netmask = socket.inet_ntoa(struct.pack('!I', (1 << 32) - (1 << host_bits)))
  return network, netmask

url = 'https://ip-ranges.amazonaws.com/ip-ranges.json'
req = urllib.request.Request(url)
r = urllib.request.urlopen(req).read()
ipRangeResponse = json.loads(r.decode('utf-8'))

for ipRange in ipRangeResponse['prefixes']:
  if (ipRange['service'] == 'CLOUDFRONT'):
    network, netmask = cidr_to_netmask(ipRange['ip_prefix'])
    print("route {} {}".format(network, netmask))