Check affected ip-addresses versus your aggregates

affected.py

#!/usr/bin/env python3
"""This checks over large text files if your ip address if on a list
particular handy with CVEs and leaked data.

syntax:
./affected.py iplistofleak.txt

Needs 2 files to start:
1:  a text file named 'aggregates' of your AS-system with CIDR notation,
    per line, no other data or empty lines. This could be /32 if needed
2:  a text file containing addresses, per line, no other data or empty lines

Example for 1:

10.0.0.0/8
192.168.1.0/24
172.19.31.10/32

Example for 2:

10.0.1.1
10.2.3.4/32
192.168.1.9

"""
import sys
from ipaddress import ip_network


def get_lines(_input_file):
    try:
        with open(_input_file, 'r') as _input:
            _lines = _input.read().splitlines()
    except FileNotFoundError:
        raise SystemExit(f"Could not read file {f}!")
    else:
        return _lines


def subnet_of(pfx):
    for aggregate in aggregates:
        if pfx.subnet_of(aggregate) or pfx == aggregate:
            return True
    return False


def matching(_input_file):
    _hits = []
    for line in get_lines(_input_file):
        route = ip_network(line)
        try:
            if subnet_of(route):
                _hits.append(route)
        except TypeError:
            # can not check ipv4 on ipv6 or vice versa
            continue
    return _hits


if __name__ == '__main__':
    try:
        input_affected = sys.argv[1]
    except IndexError:
        raise SystemExit(f"Wrong syntax")

    aggregates = []
    for line in get_lines('./aggregates'):
        aggregates.append(ip_network(line))

    affected_count = len(get_lines(input_affected))
    print(f'Scanning over {affected_count} affected ip addresses:')
    hits = matching(input_affected)
    print(f'Found {len(hits)}', end='')
    if len(hits) > 0:
        print(':')
        for item in hits:
            print(item.compressed)
    else:
        print()