diff options
Diffstat (limited to 'src/conf_mode/nat66.py')
| -rwxr-xr-x | src/conf_mode/nat66.py | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/src/conf_mode/nat66.py b/src/conf_mode/nat66.py new file mode 100755 index 000000000..dc3cd550c --- /dev/null +++ b/src/conf_mode/nat66.py @@ -0,0 +1,171 @@ +#!/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) |