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#!/usr/bin/env python3
#
# Copyright (C) 2020 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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/>.
from copy import deepcopy
from sys import exit
from netifaces import interfaces
from vyos.config import Config
from vyos.util import call
from vyos.template import render
from vyos import ConfigError
default_config_data = {
'source': [],
'destination': []
}
iptables_nat_config = '/tmp/iptables_nat_config'
def parse_source_destination(conf, source_dest):
""" Common wrapper to read in both NAT source and destination CLI """
tmp = []
base_level = ['nat', source_dest]
conf.set_level(base_level)
for number in conf.list_nodes(['rule']):
rule = {
'description': '',
'dest_address': '',
'dest_port': '',
'disable': False,
'exclude': False,
'interface_in': '',
'interface_out': '',
'log': False,
'protocol': '',
'number': number,
'source_address': '',
'source_port': '',
'translation_address': '',
'translation_port': ''
}
conf.set_level(base_level + ['rule', number])
if conf.exists(['description']):
rule['description'] = conf.return_value(['description'])
if conf.exists(['destination', 'address']):
rule['dest_address'] = conf.return_value(['destination', 'address'])
if conf.exists(['destination', 'port']):
rule['dest_port'] = conf.return_value(['destination', 'port'])
if conf.exists(['disable']):
rule['disable'] = True
if conf.exists(['exclude']):
rule['exclude'] = True
if conf.exists(['inbound-interface']):
rule['interface_in'] = conf.return_value(['inbound-interface'])
if conf.exists(['outbound-interface']):
rule['interface_out'] = conf.return_value(['outbound-interface'])
if conf.exists(['log']):
rule['log'] = True
if conf.exists(['protocol']):
rule['protocol'] = conf.return_value(['protocol'])
if conf.exists(['source', 'address']):
rule['source_address'] = conf.return_value(['source', 'address'])
if conf.exists(['source', 'port']):
rule['source_port'] = conf.return_value(['source', 'port'])
if conf.exists(['translation', 'address']):
rule['translation_address'] = conf.return_value(['translation', 'address'])
if conf.exists(['translation', 'port']):
rule['translation_port'] = conf.return_value(['translation', 'port'])
tmp.append(rule)
return tmp
def get_config():
nat = deepcopy(default_config_data)
conf = Config()
if not conf.exists(['nat']):
return None
else:
conf.set_level(['nat'])
# use a common wrapper function to read in the source / destination
# tree from the config - thus we do not need to replicate almost the
# same code :-)
for tgt in ['source', 'destination']:
nat[tgt] = parse_source_destination(conf, tgt)
return nat
def verify(nat):
if not nat:
return None
for rule in nat['source']:
interface = rule['interface_out']
if interface and interface not in interfaces():
print(f'NAT configuration warning: interface {interface} does not exist on this system')
return None
def generate(nat):
if not nat:
return None
render(iptables_nat_config, 'nat/iptables-restore.tmpl', nat, trim_blocks=True)
return None
def apply(nat):
if not nat:
return None
call(f'iptables-restore --test < {iptables_nat_config}')
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
|
