#!/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/>. import jmespath import json import os from sys import exit from netifaces import interfaces from vyos.config import Config from vyos.configdict import dict_merge from vyos.template import render from vyos.util import cmd from vyos.util import check_kmod from vyos.util import dict_search from vyos.template import is_ipv6 from vyos.xml import defaults from vyos import ConfigError from vyos import airbag airbag.enable() k_mod = ['nft_nat', 'nft_chain_nat'] iptables_nat_config = '/tmp/vyos-nat66-rules.nft' ndppd_config = '/run/ndppd/ndppd.conf' def get_handler(json, chain, target): """ Get nftable rule handler number of given chain/target combination. Handler is required when adding NAT66/Conntrack helper targets """ for x in json: if x['chain'] != chain: continue if x['target'] != target: continue return x['handle'] return None def get_config(config=None): if config: conf = config else: conf = Config() base = ['nat66'] nat = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True) # T2665: we must add the tagNode defaults individually until this is # moved to the base class for direction in ['source', 'destination']: if direction in nat: default_values = defaults(base + [direction, 'rule']) if 'rule' in nat[direction]: for rule in nat[direction]['rule']: nat[direction]['rule'][rule] = dict_merge(default_values, nat[direction]['rule'][rule]) # read in current nftable (once) for further processing tmp = cmd('nft -j list table ip6 raw') nftable_json = json.loads(tmp) # condense the full JSON table into a list with only relevand informations pattern = 'nftables[?rule].rule[?expr[].jump].{chain: chain, handle: handle, target: expr[].jump.target | [0]}' condensed_json = jmespath.search(pattern, nftable_json) if not conf.exists(base): nat['helper_functions'] = 'remove' nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK') nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT','NAT_CONNTRACK') nat['deleted'] = '' return nat # check if NAT66 connection tracking helpers need to be set up - this has to # be done only once if not get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK'): nat['helper_functions'] = 'add' # Retrieve current table handler positions nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'VYATTA_CT_PREROUTING_HOOK') nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT','VYATTA_CT_OUTPUT_HOOK') else: nat['helper_functions'] = 'has' return nat def verify(nat): if not nat or 'deleted' in nat: # no need to verify the CLI as NAT66 is going to be deactivated return None if 'helper_functions' in nat and nat['helper_functions'] != 'has': if not (nat['pre_ct_conntrack'] or nat['out_ct_conntrack']): raise Exception('could not determine nftable ruleset handlers') if dict_search('source.rule', nat): for rule, config in dict_search('source.rule', nat).items(): err_msg = f'Source NAT66 configuration error in rule {rule}:' if 'outbound_interface' not in config: raise ConfigError(f'{err_msg}\n' \ 'outbound-interface not specified') else: if config['outbound_interface'] not in interfaces(): print(f'WARNING: rule "{rule}" interface "{config["outbound_interface"]}" does not exist on this system') prefix = dict_search('translation.prefix', config) if prefix != None: if not is_ipv6(prefix): raise ConfigError(f'Warning: IPv6 prefix {prefix} is not a valid address prefix') prefix = dict_search('source.prefix', config) if prefix != None: if not is_ipv6(prefix): raise ConfigError(f'{err_msg} source-prefix not specified') if dict_search('destination.rule', nat): for rule, config in dict_search('destination.rule', nat).items(): err_msg = f'Destination NAT66 configuration error in rule {rule}:' if 'inbound_interface' not in config: raise ConfigError(f'{err_msg}\n' \ 'inbound-interface not specified') else: if config['inbound_interface'] not in 'any' and config['inbound_interface'] not in interfaces(): print(f'WARNING: rule "{rule}" interface "{config["inbound_interface"]}" does not exist on this system') return None def generate(nat): render(iptables_nat_config, 'firewall/nftables-nat66.tmpl', nat, permission=0o755) render(ndppd_config, 'proxy-ndp/ndppd.conf.tmpl', nat, permission=0o755) return None def apply(nat): if not nat: return None cmd(f'{iptables_nat_config}') if 'deleted' in nat or not dict_search('source.rule', nat): cmd('systemctl stop ndppd') if os.path.isfile(ndppd_config): os.unlink(ndppd_config) else: cmd('systemctl restart ndppd') if os.path.isfile(iptables_nat_config): os.unlink(iptables_nat_config) return None if __name__ == '__main__': try: check_kmod(k_mod) c = get_config() verify(c) generate(c) apply(c) except ConfigError as e: print(e) exit(1)