ip_subnet.py

"""
Поиск минимальной подсети, содержащей заданный набор IP-адресов.
"""
import unittest
import struct
import socket


def ip_to_bin(ip) -> str:
    ip_packed = socket.inet_aton(ip)
    ip_int = struct.unpack('!I', ip_packed)[0]
    return bin(ip_int)[2:].rjust(32, '0')


def bin_to_ip(ip_bin) -> str:
    ip_int = int(ip_bin, 2)
    ip_packed = struct.pack('!I', ip_int)
    ip = socket.inet_ntoa(ip_packed)
    return ip


def get_common_prefix(iterables) -> list:
    prefix = []
    for elems in zip(*iterables):
        if len(set(elems)) == 1:
            prefix.append(elems[0])
        else:
            break
    return prefix


def get_min_subnet(ips) -> str:
    """Минимальная подсеть, содержащая адреса ips"""
    subnet_bin_prefix = get_common_prefix(map(ip_to_bin, ips))
    subnet_bin_ip = ''.join(subnet_bin_prefix).ljust(32, '0')
    subnet_id = '%s/%s' % (bin_to_ip(subnet_bin_ip), len(subnet_bin_prefix))
    return subnet_id


class TestMinSubnet(unittest.TestCase):
    def test_get_min_subnet(self):
        test_cases = [
            ('10.10.0.1/32', [
                '10.10.0.1',
            ]),
            ('10.10.0.2/31', [
                '10.10.0.2',
                '10.10.0.3',
            ]),
            ('10.10.0.4/30', [
                '10.10.0.5',
                '10.10.0.6',
            ]),
            ('10.10.0.0/29', [
                '10.10.0.3',
                '10.10.0.4',
            ]),
            ('10.10.0.16/28', [
                '10.10.0.17',
                '10.10.0.24',
            ]),
            ('10.10.0.128/25', [
                '10.10.0.130',
                '10.10.0.200',
            ]),
            ('10.10.0.0/24', [
                '10.10.0.5',
                '10.10.0.128',
            ]),
            ('10.10.0.0/16', [
                '10.10.10.0',
                '10.10.128.2',
            ]),
            ('10.0.0.0/8', [
                '10.0.1.1',
                '10.240.1.2',
            ]),
            ('0.0.0.0/0', [
                '0.1.0.0',
                '240.10.1.2',
            ]),
        ]
        for i, (expected, inp) in enumerate(test_cases):
            with self.subTest(i=i, expected=expected, input=inp):
                subnet_id = get_min_subnet(inp)
                self.assertEqual(subnet_id, expected)


if __name__ == '__main__':
    unittest.main()