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Diffstat (limited to 'src/conf_mode/firewall-interface.py')
| -rwxr-xr-x | src/conf_mode/firewall-interface.py | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/src/conf_mode/firewall-interface.py b/src/conf_mode/firewall-interface.py new file mode 100755 index 000000000..a7442ecbd --- /dev/null +++ b/src/conf_mode/firewall-interface.py @@ -0,0 +1,172 @@ +#!/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.configdict import leaf_node_changed +from vyos.ifconfig import Section +from vyos.template import render +from vyos.util import cmd +from vyos.util import dict_search_args +from vyos.util import run +from vyos import ConfigError +from vyos import airbag +airbag.enable() + +NFT_CHAINS = { + 'in': 'VYOS_FW_FORWARD', + 'out': 'VYOS_FW_FORWARD', + 'local': 'VYOS_FW_LOCAL' +} +NFT6_CHAINS = { + 'in': 'VYOS_FW6_FORWARD', + 'out': 'VYOS_FW6_FORWARD', + 'local': 'VYOS_FW6_LOCAL' +} + +def get_config(config=None): + if config: + conf = config + else: + conf = Config() + + ifname = argv[1] + ifpath = Section.get_config_path(ifname) + if_firewall_path = f'interfaces {ifpath} firewall' + + if_firewall = conf.get_config_dict(if_firewall_path, key_mangling=('-', '_'), get_first_key=True, + no_tag_node_value_mangle=True) + + if_firewall['ifname'] = ifname + if_firewall['firewall'] = conf.get_config_dict(['firewall'], key_mangling=('-', '_'), get_first_key=True, + no_tag_node_value_mangle=True) + + return if_firewall + +def verify(if_firewall): + # bail out early - looks like removal from running config + if not if_firewall: + return None + + for direction in ['in', 'out', 'local']: + if direction in if_firewall: + if 'name' in if_firewall[direction]: + name = if_firewall[direction]['name'] + + if 'name' not in if_firewall['firewall']: + raise ConfigError('Firewall name not configured') + + if name not in if_firewall['firewall']['name']: + raise ConfigError(f'Invalid firewall name "{name}"') + + if 'ipv6_name' in if_firewall[direction]: + name = if_firewall[direction]['ipv6_name'] + + if 'ipv6_name' not in if_firewall['firewall']: + raise ConfigError('Firewall ipv6-name not configured') + + if name not in if_firewall['firewall']['ipv6_name']: + raise ConfigError(f'Invalid firewall ipv6-name "{name}"') + + return None + +def generate(if_firewall): + return None + +def cleanup_rule(table, chain, prefix, ifname, new_name=None): + results = cmd(f'nft -a list chain {table} {chain}').split("\n") + retval = None + for line in results: + if f'{prefix}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: + run(f'nft delete rule {table} {chain} handle {handle_search[1]}') + return retval + +def state_policy_handle(table, chain): + # Find any state-policy rule to ensure interface rules are only inserted afterwards + results = cmd(f'nft -a list chain {table} {chain}').split("\n") + for line in results: + if 'jump VYOS_STATE_POLICY' in line: + handle_search = re.search('handle (\d+)', line) + if handle_search: + return handle_search[1] + return None + +def apply(if_firewall): + ifname = if_firewall['ifname'] + + for direction in ['in', 'out', 'local']: + chain = NFT_CHAINS[direction] + ipv6_chain = NFT6_CHAINS[direction] + if_prefix = 'i' if direction in ['in', 'local'] else 'o' + + name = dict_search_args(if_firewall, direction, 'name') + if name: + rule_exists = cleanup_rule('ip filter', chain, if_prefix, ifname, name) + + if not rule_exists: + rule_action = 'insert' + rule_prefix = '' + + handle = state_policy_handle('ip filter', chain) + if handle: + rule_action = 'add' + rule_prefix = f'position {handle}' + + run(f'nft {rule_action} rule ip filter {chain} {rule_prefix} {if_prefix}ifname {ifname} counter jump {name}') + else: + cleanup_rule('ip filter', chain, if_prefix, ifname) + + ipv6_name = dict_search_args(if_firewall, direction, 'ipv6_name') + if ipv6_name: + rule_exists = cleanup_rule('ip6 filter', ipv6_chain, if_prefix, ifname, ipv6_name) + + if not rule_exists: + rule_action = 'insert' + rule_prefix = '' + + handle = state_policy_handle('ip6 filter', ipv6_chain) + if handle: + rule_action = 'add' + rule_prefix = f'position {handle}' + + run(f'nft {rule_action} rule ip6 filter {ipv6_chain} {rule_prefix} {if_prefix}ifname {ifname} counter jump {ipv6_name}') + else: + cleanup_rule('ip6 filter', ipv6_chain, if_prefix, ifname) + + return None + +if __name__ == '__main__': + try: + c = get_config() + verify(c) + generate(c) + apply(c) + except ConfigError as e: + print(e) + exit(1) |