firewall/nat.py

#! /usr/bin/python3

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

# Copyright © 2019 Hugo Levy-Falk <me@klafyvel.me>

"""
Creates the nat set.
"""

import logging
import time
import os
from configparser import ConfigParser

import netaddr

from firewall import NAT

BASE_DIR = os.path.dirname(os.path.abspath(__file__))

CONFIG = ConfigParser()
CONFIG.read(os.path.join(BASE_DIR, 'config.ini'))


def create_nat_adherent():
    range_in = CONFIG['NAT']['range_in_adherent']
    range_out = CONFIG['NAT']['range_out_adherent']
    first_port = int(CONFIG['NAT']['first_port_adherent'])
    last_port = int(CONFIG['NAT']['last_port_adherent'])
    return NAT(
        'adherent',
        range_in,
        range_out,
        first_port,
        last_port
    )


def create_nat_federez():
    range_in = CONFIG['NAT']['range_in_federez']
    range_out = CONFIG['NAT']['range_out_federez']
    first_port = int(CONFIG['NAT']['first_port_federez'])
    last_port = int(CONFIG['NAT']['last_port_federez'])
    return NAT(
        'federez',
        range_in,
        range_out,
        first_port,
        last_port
    )


def create_nat_aloes():
    range_in = CONFIG['NAT']['range_in_aloes']
    range_out = CONFIG['NAT']['range_out_aloes']
    first_port = int(CONFIG['NAT']['first_port_aloes'])
    last_port = int(CONFIG['NAT']['last_port_aloes'])
    return NAT(
        'aloes',
        range_in,
        range_out,
        first_port,
        last_port
    )


def main():
    ctime = time.ctime()
    nat_log = ctime + "\n"
    logging.info("Creating adherent nat...")
    nat_adherent = create_nat_adherent()
    nat_log += "Adherents :\n"
    nat_log += nat_adherent.manage()
    logging.info("Done.")
    logging.info("Creating federez nat...")
    nat_federez = create_nat_federez()
    nat_log += "Federez :\n"
    nat_log += nat_federez.manage()
    logging.info("Done.")
    logging.info("Creating aloes nat...")
    aloes_nat = create_nat_aloes()
    nat_log += "Aloes :\n"
    nat_log += aloes_nat.manage()
    logging.info("Done.")

    nat_directory = "/var/log/nat/"
    if not os.path.exists(nat_directory):
        os.makedirs(nat_directory)
    filename = os.path.join(nat_directory, "nat_%s.log" % time.strftime('%Y_%m_%d_%Hh_%Mm'))

    logging.info("Saving nat table into " + filename)
    with open(filename, 'a') as f:
        f.write(nat_log)


if __name__=='__main__':
    logging.info('Updating the NAT table.')
    main()