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-rwxr-xr-xsrc/conf_mode/firewall-interface.py169
1 files changed, 169 insertions, 0 deletions
diff --git a/src/conf_mode/firewall-interface.py b/src/conf_mode/firewall-interface.py
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+++ b/src/conf_mode/firewall-interface.py
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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.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_IN',
+ 'out': 'VYOS_FW_OUT',
+ 'local': 'VYOS_FW_LOCAL'
+}
+NFT6_CHAINS = {
+ 'in': 'VYOS_FW6_IN',
+ 'out': 'VYOS_FW6_OUT',
+ '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, 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:
+ run(f'nft delete rule {table} {chain} handle {handle_search[1]}')
+ return retval
+
+def state_policy_handle(table, chain):
+ 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, ifname, name)
+ rule_action = 'insert'
+ rule_prefix = ''
+
+ if not rule_exists:
+ 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, ifname)
+
+ ipv6_name = dict_search_args(if_firewall, direction, 'ipv6_name')
+ if ipv6_name:
+ rule_exists = cleanup_rule('ip6 filter', ipv6_chain, ifname, ipv6_name)
+ rule_action = 'insert'
+ rule_prefix = ''
+
+ if not rule_exists:
+ handle = state_policy_handle('ip filter', 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, ifname)
+
+ return None
+
+if __name__ == '__main__':
+ try:
+ c = get_config()
+ verify(c)
+ generate(c)
+ apply(c)
+ except ConfigError as e:
+ print(e)
+ exit(1)