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#!/usr/bin/env python3
#
# Copyright (C) 2021 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/>.
import os
import re
from sys import argv
from sys import exit
from vyos.config import Config
from vyos.ifconfig import Section
from vyos.template import render
from vyos.util import cmd
from vyos import ConfigError
from vyos import airbag
airbag.enable()
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
ifname = argv[1]
ifpath = Section.get_config_path(ifname)
if_policy_path = f'interfaces {ifpath} policy'
if_policy = conf.get_config_dict(if_policy_path, key_mangling=('-', '_'), get_first_key=True,
no_tag_node_value_mangle=True)
if_policy['ifname'] = ifname
if_policy['policy'] = conf.get_config_dict(['policy'], key_mangling=('-', '_'), get_first_key=True,
no_tag_node_value_mangle=True)
return if_policy
def verify(if_policy):
# bail out early - looks like removal from running config
if not if_policy:
return None
for route in ['route', 'route6']:
if route in if_policy:
if route not in if_policy['policy']:
raise ConfigError('Policy route not configured')
route_name = if_policy[route]
if route_name not in if_policy['policy'][route]:
raise ConfigError(f'Invalid policy route name "{name}"')
return None
def generate(if_policy):
return None
def cleanup_rule(table, chain, ifname, new_name=None):
results = cmd(f'nft -a list chain {table} {chain}').split("\n")
retval = None
for line in results:
if f'ifname "{ifname}"' in line:
if new_name and f'jump {new_name}' in line:
# new_name is used to clear rules for any previously referenced chains
# returns true when rule exists and doesn't need to be created
retval = True
continue
handle_search = re.search('handle (\d+)', line)
if handle_search:
cmd(f'nft delete rule {table} {chain} handle {handle_search[1]}')
return retval
def apply(if_policy):
ifname = if_policy['ifname']
route_chain = 'VYOS_PBR_PREROUTING'
ipv6_route_chain = 'VYOS_PBR6_PREROUTING'
if 'route' in if_policy:
name = 'VYOS_PBR_' + if_policy['route']
rule_exists = cleanup_rule('ip mangle', route_chain, ifname, name)
if not rule_exists:
cmd(f'nft insert rule ip mangle {route_chain} iifname {ifname} counter jump {name}')
else:
cleanup_rule('ip mangle', route_chain, ifname)
if 'route6' in if_policy:
name = 'VYOS_PBR6_' + if_policy['route6']
rule_exists = cleanup_rule('ip6 mangle', ipv6_route_chain, ifname, name)
if not rule_exists:
cmd(f'nft insert rule ip6 mangle {ipv6_route_chain} iifname {ifname} counter jump {name}')
else:
cleanup_rule('ip6 mangle', ipv6_route_chain, ifname)
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
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