#!/usr/bin/env python3 # # Copyright (C) 2020-2021 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 . from sys import exit from vyos.config import Config from vyos.configdict import dict_merge from vyos.template import render from vyos.template import render_to_string from vyos.util import call from vyos.util import dict_search from vyos import ConfigError from vyos import frr from vyos import airbag airbag.enable() config_file = r'/tmp/bgp.frr' def get_config(): conf = Config() base = ['protocols', 'bgp'] bgp = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True) if not conf.exists(base): return bgp # We also need some additional information from the config, # prefix-lists and route-maps for instance. base = ['policy'] tmp = conf.get_config_dict(base, key_mangling=('-', '_')) # As we only support one ASN (later checked in begin of verify()) we add the # new information only to the first AS number asn = next(iter(bgp)) # Merge policy dict into bgp dict bgp[asn] = dict_merge(tmp, bgp[asn]) return bgp def verify(bgp): if not bgp: return None # Check if declared more than one ASN if len(bgp) > 1: raise ConfigError('Only one BGP AS number can be defined!') for asn, asn_config in bgp.items(): # Common verification for both peer-group and neighbor statements for neighbor in ['neighbor', 'peer_group']: # bail out early if there is no neighbor or peer-group statement # this also saves one indention level if neighbor not in asn_config: continue for peer, peer_config in asn_config[neighbor].items(): # Only regular "neighbor" statement can have a peer-group set # Check if the configure peer-group exists if 'peer_group' in peer_config: peer_group = peer_config['peer_group'] if peer_group not in asn_config['peer_group']: raise ConfigError(f'Specified peer-group "{peer_group}" for '\ f'neighbor "{neighbor}" does not exist!') # Some checks can/must only be done on a neighbor and nor a peer-group if neighbor == 'neighbor': # remote-as must be either set explicitly for the neighbor # or for the entire peer-group if 'remote_as' not in peer_config: if 'peer_group' not in peer_config or 'remote_as' not in asn_config['peer_group'][peer_config['peer_group']]: raise ConfigError('Remote AS must be set for neighbor or peer-group!') for afi in ['ipv4_unicast', 'ipv6_unicast']: # Bail out early if address family is not configured if 'address_family' not in peer_config or afi not in peer_config['address_family']: continue afi_config = peer_config['address_family'][afi] # Validate if configured Prefix list exists if 'prefix_list' in afi_config: for tmp in ['import', 'export']: if tmp not in afi_config['prefix_list']: # bail out early continue # get_config_dict() mangles all '-' characters to '_' this is legitimate, thus all our # compares will run on '_' as also '_' is a valid name for a prefix-list prefix_list = afi_config['prefix_list'][tmp].replace('-', '_') if afi == 'ipv4_unicast': if dict_search(f'policy.prefix_list.{prefix_list}', asn_config) == None: raise ConfigError(f'prefix-list "{prefix_list}" used for "{tmp}" does not exist!') elif afi == 'ipv6_unicast': if dict_search(f'policy.prefix_list6.{prefix_list}', asn_config) == None: raise ConfigError(f'prefix-list6 "{prefix_list}" used for "{tmp}" does not exist!') if 'route_map' in afi_config: for tmp in ['import', 'export']: if tmp in afi_config['route_map']: # get_config_dict() mangles all '-' characters to '_' this is legitim, thus all our # compares will run on '_' as also '_' is a valid name for a route-map route_map = afi_config['route_map'][tmp].replace('-', '_') if dict_search(f'policy.route_map.{route_map}', asn_config) == None: raise ConfigError(f'route-map "{route_map}" used for "{tmp}" does not exist!') # Throw an error if a peer group is not configured for allow range if 'listen' in asn_config: if 'range' in asn_config['listen']: for prefix in asn_config['listen']['range']: if not 'peer_group' in asn_config['listen']['range'].get(prefix): raise ConfigError(f'Listen range for prefix "{prefix}" has no peer group configured.') return None def generate(bgp): if not bgp: bgp['new_frr_config'] = '' return None # only one BGP AS is supported, so we can directly send the first key # of the config dict asn = list(bgp.keys())[0] bgp[asn]['asn'] = asn # render(config) not needed, its only for debug render(config_file, 'frr/bgp.frr.tmpl', bgp[asn]) bgp['new_frr_config'] = render_to_string('frr/bgp.frr.tmpl', bgp[asn]) return None def apply(bgp): # Save original configuration prior to starting any commit actions frr_cfg = frr.FRRConfig() frr_cfg.load_configuration(daemon='bgpd') frr_cfg.modify_section(f'router bgp \S+', '') frr_cfg.add_before(r'(ip prefix-list .*|route-map .*|line vty)', bgp['new_frr_config']) frr_cfg.commit_configuration(daemon='bgpd') # If FRR config is blank, rerun the blank commit x times due to frr-reload # behavior/bug not properly clearing out on one commit. if bgp['new_frr_config'] == '': for a in range(5): frr_cfg.commit_configuration(daemon='bgpd') # Debugging ''' print('') print('--------- DEBUGGING ----------') print(f'Existing config:\n{frr_cfg["original_config"]}\n\n') print(f'Replacement config:\n{bgp["new_frr_config"]}\n\n') print(f'Modified config:\n{frr_cfg["modified_config"]}\n\n') ''' return None if __name__ == '__main__': try: c = get_config() verify(c) generate(c) apply(c) except ConfigError as e: print(e) exit(1)