useful utils to help manipulate ip networks (e.g. get routes excluding a certain country)

ip_utils.py

#!/usr/bin/env python

import re
from math import log
from urllib.request import urlopen
from ipaddress import *
from intervaltree import *
from copy import deepcopy

# the default info url is only for ip addresses assigned from apnic (asia-pacific)
def ipv4_networks_by_country(country_code, info_url='https://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest'):
    return list(collapse_addresses( [
        IPv4Network(  '{}/{}'.format( start_ip, 32 - int(log(int(num_ip), 2)) )  )
        for start_ip, num_ip in \
            re.findall(
                 r'apnic\|{}\|ipv4\|([0-9\.]+)\|([0-9]+)\|[0-9]+\|a.*'.format( country_code ),
                 urlopen(info_url).read().decode('utf8'),
                 re.IGNORECASE
            )
    ] ))

def nets_to_tree(nets):
    t = IntervalTree()
    for net in nets:
        t[ net[0] : net[-1] ] = True
    return t

def tree_to_nets(tree):
    return list(collapse_addresses( sum([
        list( summarize_address_range(itvl.begin, itvl.end) )
        for itvl in tree
    ], []) ))

def chop_from(tree1, tree2):
    tree1 = deepcopy(tree1)
    for itvl in tree2:
        tree1.chop(itvl.begin - 1, itvl.end + 1)
    return tree1

def get_nets_noncn():
    nets_cn = ipv4_networks_by_country('cn') + [
        IPv4Network('10.0.0.0/8'),
        IPv4Network('172.16.0.0/12'),
        IPv4Network('192.168.0.0/16')
    ]
    tree_cn = nets_to_tree(nets_cn)
    tree_all = nets_to_tree([ IPv4Network('0.0.0.0/0') ])
    tree_noncn = chop_from(tree_all, tree_cn)
    nets_non_cn = tree_to_nets(tree_noncn)
    return nets_non_cn