#!/usr/bin/env python3 # # Copyright (C) 2019 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 sys import jinja2 import copy import os import vyos.validate from vyos import ConfigError from vyos.config import Config config_file = r'/tmp/bfd.frr' # Please be careful if you edit the template. config_tmpl = """ ! bfd {% for peer in old_peers -%} no peer {{ peer }} {% endfor -%} ! {% for peer in new_peers -%} peer {{ peer.remote }}{% if peer.multihop %} multihop{% endif %}{% if peer.src_addr %} local-address {{ peer.src_addr }}{% endif %}{% if peer.src_if %} interface {{ peer.src_if }}{% endif %} detect-multiplier {{ peer.multiplier }} receive-interval {{ peer.rx_interval }} transmit-interval {{ peer.tx_interval }} {% if not peer.shutdown %}no {% endif %}shutdown {% endfor -%} ! """ default_config_data = { 'new_peers': [], 'old_peers' : [] } def get_config(): bfd = copy.deepcopy(default_config_data) conf = Config() if not (conf.exists('protocols bfd') or conf.exists_effective('protocols bfd')): return None else: conf.set_level('protocols bfd') # as we have to use vtysh to talk to FRR we also need to know # which peers are gone due to a config removal - thus we read in # all peers (active or to delete) bfd['old_peers'] = conf.list_effective_nodes('peer') for peer in conf.list_nodes('peer'): conf.set_level('protocols bfd peer {0}'.format(peer)) bfd_peer = { 'remote': peer, 'shutdown': False, 'src_if': '', 'src_addr': '', 'multiplier': '3', 'rx_interval': '300', 'tx_interval': '300', 'multihop': False } # Check if individual peer is disabled if conf.exists('shutdown'): bfd_peer['shutdown'] = True # Check if peer has a local source interface configured if conf.exists('source interface'): bfd_peer['src_if'] = conf.return_value('source interface') # Check if peer has a local source address configured - this is mandatory for IPv6 if conf.exists('source address'): bfd_peer['src_addr'] = conf.return_value('source address') # Tell BFD daemon that we should expect packets with TTL less than 254 # (because it will take more than one hop) and to listen on the multihop # port (4784) if conf.exists('multihop'): bfd_peer['multihop'] = True # Configures the minimum interval that this system is capable of receiving # control packets. The default value is 300 milliseconds. if conf.exists('interval receive'): bfd_peer['rx_interval'] = conf.return_value('interval receive') # The minimum transmission interval (less jitter) that this system wants # to use to send BFD control packets. if conf.exists('interval transmit'): bfd_peer['tx_interval'] = conf.return_value('interval transmit') # Configures the detection multiplier to determine packet loss. The remote # transmission interval will be multiplied by this value to determine the # connection loss detection timer. The default value is 3. if conf.exists('interval multiplier'): bfd_peer['multiplier'] = conf.return_value('interval multiplier') bfd['new_peers'].append(bfd_peer) return bfd def verify(bfd): if bfd is None: return None for peer in bfd['new_peers']: # Bail out early if peer is shutdown if peer['shutdown']: continue # IPv6 peers require an explicit local address/interface combination if vyos.validate.is_ipv6(peer['remote']): if not (peer['src_if'] and peer['src_addr']): raise ConfigError('BFD IPv6 peers require explicit local address/interface setting') # multihop doesn't accept interface names if peer['multihop'] and peer['src_if']: raise ConfigError('multihop does not accept interface names') return None def generate(bfd): if bfd is None: return None return None def apply(bfd): if bfd is None: return None tmpl = jinja2.Template(config_tmpl) config_text = tmpl.render(bfd) with open(config_file, 'w') as f: f.write(config_text) os.system("sudo vtysh -d bfdd -f " + config_file) if os.path.exists(config_file): os.remove(config_file) return None if __name__ == '__main__': try: c = get_config() verify(c) generate(c) apply(c) except ConfigError as e: print(e) sys.exit(1)