diff options
Diffstat (limited to 'src/conf_mode/dns_forwarding.py')
| -rwxr-xr-x | src/conf_mode/dns_forwarding.py | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/conf_mode/dns_forwarding.py b/src/conf_mode/dns_forwarding.py new file mode 100755 index 000000000..51631dc16 --- /dev/null +++ b/src/conf_mode/dns_forwarding.py @@ -0,0 +1,216 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2018-2020 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 os + +from sys import exit +from copy import deepcopy + +from vyos.config import Config +from vyos.hostsd_client import Client as hostsd_client +from vyos import ConfigError +from vyos.util import call, chown +from vyos.template import render + +from vyos import airbag +airbag.enable() + +pdns_rec_user = pdns_rec_group = 'pdns' +pdns_rec_run_dir = '/run/powerdns' +pdns_rec_lua_conf_file = f'{pdns_rec_run_dir}/recursor.conf.lua' +pdns_rec_hostsd_lua_conf_file = f'{pdns_rec_run_dir}/recursor.vyos-hostsd.conf.lua' +pdns_rec_hostsd_zones_file = f'{pdns_rec_run_dir}/recursor.forward-zones.conf' +pdns_rec_config_file = f'{pdns_rec_run_dir}/recursor.conf' + +default_config_data = { + 'allow_from': [], + 'cache_size': 10000, + 'export_hosts_file': 'yes', + 'listen_address': [], + 'name_servers': [], + 'negative_ttl': 3600, + 'system': False, + 'domains': {}, + 'dnssec': 'process-no-validate', + 'dhcp_interfaces': [] +} + +hostsd_tag = 'static' + +def get_config(conf): + dns = deepcopy(default_config_data) + base = ['service', 'dns', 'forwarding'] + + if not conf.exists(base): + return None + + conf.set_level(base) + + if conf.exists(['allow-from']): + dns['allow_from'] = conf.return_values(['allow-from']) + + if conf.exists(['cache-size']): + cache_size = conf.return_value(['cache-size']) + dns['cache_size'] = cache_size + + if conf.exists('negative-ttl'): + negative_ttl = conf.return_value(['negative-ttl']) + dns['negative_ttl'] = negative_ttl + + if conf.exists(['domain']): + for domain in conf.list_nodes(['domain']): + conf.set_level(base + ['domain', domain]) + entry = { + 'nslist': bracketize_ipv6_addrs(conf.return_values(['server'])), + 'addNTA': conf.exists(['addnta']), + 'recursion-desired': conf.exists(['recursion-desired']) + } + dns['domains'][domain] = entry + + conf.set_level(base) + + if conf.exists(['ignore-hosts-file']): + dns['export_hosts_file'] = "no" + + if conf.exists(['name-server']): + dns['name_servers'] = bracketize_ipv6_addrs( + conf.return_values(['name-server'])) + + if conf.exists(['system']): + dns['system'] = True + + if conf.exists(['listen-address']): + dns['listen_address'] = conf.return_values(['listen-address']) + + if conf.exists(['dnssec']): + dns['dnssec'] = conf.return_value(['dnssec']) + + if conf.exists(['dhcp']): + dns['dhcp_interfaces'] = conf.return_values(['dhcp']) + + return dns + +def bracketize_ipv6_addrs(addrs): + """Wraps each IPv6 addr in addrs in [], leaving IPv4 addrs untouched.""" + return ['[{0}]'.format(a) if a.count(':') > 1 else a for a in addrs] + +def verify(conf, dns): + # bail out early - looks like removal from running config + if dns is None: + return None + + if not dns['listen_address']: + raise ConfigError( + "Error: DNS forwarding requires a listen-address") + + if not dns['allow_from']: + raise ConfigError( + "Error: DNS forwarding requires an allow-from network") + + if dns['domains']: + for domain in dns['domains']: + if not dns['domains'][domain]['nslist']: + raise ConfigError(( + f'Error: No server configured for domain {domain}')) + + no_system_nameservers = False + if dns['system'] and not ( + conf.exists(['system', 'name-server']) or + conf.exists(['system', 'name-servers-dhcp']) ): + no_system_nameservers = True + print(("DNS forwarding warning: No 'system name-server' or " + "'system name-servers-dhcp' set\n")) + + if (no_system_nameservers or not dns['system']) and not ( + dns['name_servers'] or dns['dhcp_interfaces']): + print(("DNS forwarding warning: No 'dhcp', 'name-server' or 'system' " + "nameservers set. Forwarding will operate as a recursor.\n")) + + return None + +def generate(dns): + # bail out early - looks like removal from running config + if dns is None: + return None + + render(pdns_rec_config_file, 'dns-forwarding/recursor.conf.tmpl', + dns, user=pdns_rec_user, group=pdns_rec_group) + + render(pdns_rec_lua_conf_file, 'dns-forwarding/recursor.conf.lua.tmpl', + dns, user=pdns_rec_user, group=pdns_rec_group) + + # if vyos-hostsd didn't create its files yet, create them (empty) + for f in [pdns_rec_hostsd_lua_conf_file, pdns_rec_hostsd_zones_file]: + with open(f, 'a'): + pass + chown(f, user=pdns_rec_user, group=pdns_rec_group) + + return None + +def apply(dns): + if dns is None: + # DNS forwarding is removed in the commit + call("systemctl stop pdns-recursor.service") + if os.path.isfile(pdns_rec_config_file): + os.unlink(pdns_rec_config_file) + else: + ### first apply vyos-hostsd config + hc = hostsd_client() + + # add static nameservers to hostsd so they can be joined with other + # sources + hc.delete_name_servers([hostsd_tag]) + if dns['name_servers']: + hc.add_name_servers({hostsd_tag: dns['name_servers']}) + + # delete all nameserver tags + hc.delete_name_server_tags_recursor(hc.get_name_server_tags_recursor()) + + ## add nameserver tags - the order determines the nameserver order! + # our own tag (static) + hc.add_name_server_tags_recursor([hostsd_tag]) + + if dns['system']: + hc.add_name_server_tags_recursor(['system']) + else: + hc.delete_name_server_tags_recursor(['system']) + + # add dhcp nameserver tags for configured interfaces + for intf in dns['dhcp_interfaces']: + hc.add_name_server_tags_recursor(['dhcp-' + intf, 'dhcpv6-' + intf ]) + + # hostsd will generate the forward-zones file + # the list and keys() are required as get returns a dict, not list + hc.delete_forward_zones(list(hc.get_forward_zones().keys())) + if dns['domains']: + hc.add_forward_zones(dns['domains']) + + # call hostsd to generate forward-zones and its lua-config-file + hc.apply() + + ### finally (re)start pdns-recursor + call("systemctl restart pdns-recursor.service") + +if __name__ == '__main__': + try: + conf = Config() + c = get_config(conf) + verify(conf, c) + generate(c) + apply(c) + except ConfigError as e: + print(e) + exit(1) |