#!/usr/bin/env python3 # # Copyright (C) 2021-2022 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/>. from sys import exit from vyos.config import Config from vyos.configdict import dict_merge from vyos.template import render_to_string from vyos.utils.dict import dict_search from vyos import ConfigError from vyos import frr from vyos import airbag airbag.enable() def community_action_compatibility(actions: dict) -> bool: """ Check compatibility of values in community and large community sections :param actions: dictionary with community :type actions: dict :return: true if compatible, false if not :rtype: bool """ if ('none' in actions) and ('replace' in actions or 'add' in actions): return False if 'replace' in actions and 'add' in actions: return False if ('delete' in actions) and ('none' in actions or 'replace' in actions): return False return True def extcommunity_action_compatibility(actions: dict) -> bool: """ Check compatibility of values in extended community sections :param actions: dictionary with community :type actions: dict :return: true if compatible, false if not :rtype: bool """ if ('none' in actions) and ( 'rt' in actions or 'soo' in actions or 'bandwidth' in actions or 'bandwidth_non_transitive' in actions): return False if ('bandwidth_non_transitive' in actions) and ('bandwidth' not in actions): return False return True def routing_policy_find(key, dictionary): # Recursively traverse a dictionary and extract the value assigned to # a given key as generator object. This is made for routing policies, # thus also import/export is checked for k, v in dictionary.items(): if k == key: if isinstance(v, dict): for a, b in v.items(): if a in ['import', 'export']: yield b else: yield v elif isinstance(v, dict): for result in routing_policy_find(key, v): yield result elif isinstance(v, list): for d in v: if isinstance(d, dict): for result in routing_policy_find(key, d): yield result def get_config(config=None): if config: conf = config else: conf = Config() base = ['policy'] policy = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True, no_tag_node_value_mangle=True) # We also need some additional information from the config, prefix-lists # and route-maps for instance. They will be used in verify(). # # XXX: one MUST always call this without the key_mangling() option! See # vyos.configverify.verify_common_route_maps() for more information. tmp = conf.get_config_dict(['protocols'], key_mangling=('-', '_'), no_tag_node_value_mangle=True) # Merge policy dict into "regular" config dict policy = dict_merge(tmp, policy) return policy def verify(policy): if not policy: return None for policy_type in ['access_list', 'access_list6', 'as_path_list', 'community_list', 'extcommunity_list', 'large_community_list', 'prefix_list', 'prefix_list6', 'route_map']: # Bail out early and continue with next policy type if policy_type not in policy: continue # instance can be an ACL name/number, prefix-list name or route-map name for instance, instance_config in policy[policy_type].items(): # If no rule was found within the instance ... sad, but we can leave # early as nothing needs to be verified if 'rule' not in instance_config: continue # human readable instance name (hypen instead of underscore) policy_hr = policy_type.replace('_', '-') entries = [] for rule, rule_config in instance_config['rule'].items(): mandatory_error = f'must be specified for "{policy_hr} {instance} rule {rule}"!' if 'action' not in rule_config: raise ConfigError(f'Action {mandatory_error}') if policy_type == 'access_list': if 'source' not in rule_config: raise ConfigError(f'A source {mandatory_error}') if int(instance) in range(100, 200) or int( instance) in range(2000, 2700): if 'destination' not in rule_config: raise ConfigError( f'A destination {mandatory_error}') if policy_type == 'access_list6': if 'source' not in rule_config: raise ConfigError(f'A source {mandatory_error}') if policy_type in ['as_path_list', 'community_list', 'extcommunity_list', 'large_community_list']: if 'regex' not in rule_config: raise ConfigError(f'A regex {mandatory_error}') if policy_type in ['prefix_list', 'prefix_list6']: if 'prefix' not in rule_config: raise ConfigError(f'A prefix {mandatory_error}') if rule_config in entries: raise ConfigError( f'Rule "{rule}" contains a duplicate prefix definition!') entries.append(rule_config) # route-maps tend to be a bit more complex so they get their own verify() section if 'route_map' in policy: for route_map, route_map_config in policy['route_map'].items(): if 'rule' not in route_map_config: continue for rule, rule_config in route_map_config['rule'].items(): # Action 'deny' cannot be used with "continue" # FRR does not validate it T4827 if rule_config['action'] == 'deny' and 'continue' in rule_config: raise ConfigError(f'rule {rule} "continue" cannot be used with action deny!') # Specified community-list must exist tmp = dict_search('match.community.community_list', rule_config) if tmp and tmp not in policy.get('community_list', []): raise ConfigError(f'community-list {tmp} does not exist!') # Specified extended community-list must exist tmp = dict_search('match.extcommunity', rule_config) if tmp and tmp not in policy.get('extcommunity_list', []): raise ConfigError( f'extcommunity-list {tmp} does not exist!') # Specified large-community-list must exist tmp = dict_search('match.large_community.large_community_list', rule_config) if tmp and tmp not in policy.get('large_community_list', []): raise ConfigError( f'large-community-list {tmp} does not exist!') # Specified prefix-list must exist tmp = dict_search('match.ip.address.prefix_list', rule_config) if tmp and tmp not in policy.get('prefix_list', []): raise ConfigError(f'prefix-list {tmp} does not exist!') # Specified prefix-list must exist tmp = dict_search('match.ipv6.address.prefix_list', rule_config) if tmp and tmp not in policy.get('prefix_list6', []): raise ConfigError(f'prefix-list6 {tmp} does not exist!') # Specified access_list6 in nexthop must exist tmp = dict_search('match.ipv6.nexthop.access_list', rule_config) if tmp and tmp not in policy.get('access_list6', []): raise ConfigError(f'access_list6 {tmp} does not exist!') # Specified prefix-list6 in nexthop must exist tmp = dict_search('match.ipv6.nexthop.prefix_list', rule_config) if tmp and tmp not in policy.get('prefix_list6', []): raise ConfigError(f'prefix-list6 {tmp} does not exist!') tmp = dict_search('set.community.delete', rule_config) if tmp and tmp not in policy.get('community_list', []): raise ConfigError(f'community-list {tmp} does not exist!') tmp = dict_search('set.large_community.delete', rule_config) if tmp and tmp not in policy.get('large_community_list', []): raise ConfigError( f'large-community-list {tmp} does not exist!') if 'set' in rule_config: rule_action = rule_config['set'] if 'community' in rule_action: if not community_action_compatibility( rule_action['community']): raise ConfigError( f'Unexpected combination between action replace, add, delete or none in community') if 'large_community' in rule_action: if not community_action_compatibility( rule_action['large_community']): raise ConfigError( f'Unexpected combination between action replace, add, delete or none in large-community') if 'extcommunity' in rule_action: if not extcommunity_action_compatibility( rule_action['extcommunity']): raise ConfigError( f'Unexpected combination between none, rt, soo, bandwidth, bandwidth-non-transitive in extended-community') # When routing protocols are active some use prefix-lists, route-maps etc. # to apply the systems routing policy to the learned or redistributed routes. # When the "routing policy" changes and policies, route-maps etc. are deleted, # it is our responsibility to verify that the policy can not be deleted if it # is used by any routing protocol if 'protocols' in policy: for policy_type in ['access_list', 'access_list6', 'as_path_list', 'community_list', 'extcommunity_list', 'large_community_list', 'prefix_list', 'route_map']: if policy_type in policy: for policy_name in list(set(routing_policy_find(policy_type, policy[ 'protocols']))): found = False if policy_name in policy[policy_type]: found = True # BGP uses prefix-list for selecting both an IPv4 or IPv6 AFI related # list - we need to go the extra mile here and check both prefix-lists if policy_type == 'prefix_list' and 'prefix_list6' in policy and policy_name in \ policy['prefix_list6']: found = True if not found: tmp = policy_type.replace('_', '-') raise ConfigError( f'Can not delete {tmp} "{policy_name}", still in use!') return None def generate(policy): if not policy: return None policy['new_frr_config'] = render_to_string('frr/policy.frr.j2', policy) return None def apply(policy): bgp_daemon = 'bgpd' zebra_daemon = 'zebra' # Save original configuration prior to starting any commit actions frr_cfg = frr.FRRConfig() # The route-map used for the FIB (zebra) is part of the zebra daemon frr_cfg.load_configuration(bgp_daemon) frr_cfg.modify_section(r'^bgp as-path access-list .*') frr_cfg.modify_section(r'^bgp community-list .*') frr_cfg.modify_section(r'^bgp extcommunity-list .*') frr_cfg.modify_section(r'^bgp large-community-list .*') frr_cfg.modify_section(r'^route-map .*', stop_pattern='^exit', remove_stop_mark=True) if 'new_frr_config' in policy: frr_cfg.add_before(frr.default_add_before, policy['new_frr_config']) frr_cfg.commit_configuration(bgp_daemon) # The route-map used for the FIB (zebra) is part of the zebra daemon frr_cfg.load_configuration(zebra_daemon) frr_cfg.modify_section(r'^access-list .*') frr_cfg.modify_section(r'^ipv6 access-list .*') frr_cfg.modify_section(r'^ip prefix-list .*') frr_cfg.modify_section(r'^ipv6 prefix-list .*') frr_cfg.modify_section(r'^route-map .*', stop_pattern='^exit', remove_stop_mark=True) if 'new_frr_config' in policy: frr_cfg.add_before(frr.default_add_before, policy['new_frr_config']) frr_cfg.commit_configuration(zebra_daemon) return None if __name__ == '__main__': try: c = get_config() verify(c) generate(c) apply(c) except ConfigError as e: print(e) exit(1)