diff options
Diffstat (limited to 'src/conf_mode/protocols_bfd.py')
| -rwxr-xr-x | src/conf_mode/protocols_bfd.py | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/conf_mode/protocols_bfd.py b/src/conf_mode/protocols_bfd.py new file mode 100755 index 000000000..c8e791c78 --- /dev/null +++ b/src/conf_mode/protocols_bfd.py @@ -0,0 +1,216 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2019-2020 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.validate import is_ipv6_link_local, is_ipv6 +from vyos import ConfigError +from vyos.util import call +from vyos.template import render + +from vyos import airbag +airbag.enable() + +config_file = r'/tmp/bfd.frr' + +default_config_data = { + 'new_peers': [], + 'old_peers' : [] +} + +# get configuration for BFD peer from proposed or effective configuration +def get_bfd_peer_config(peer, conf_mode="proposed"): + conf = Config() + 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, + 'echo_interval': '', + 'echo_mode': False, + } + + # Check if individual peer is disabled + if conf_mode == "effective" and conf.exists_effective('shutdown'): + bfd_peer['shutdown'] = True + if conf_mode == "proposed" and conf.exists('shutdown'): + bfd_peer['shutdown'] = True + + # Check if peer has a local source interface configured + if conf_mode == "effective" and conf.exists_effective('source interface'): + bfd_peer['src_if'] = conf.return_effective_value('source interface') + if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('source address'): + bfd_peer['src_addr'] = conf.return_effective_value('source address') + if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('multihop'): + bfd_peer['multihop'] = True + if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval receive'): + bfd_peer['rx_interval'] = conf.return_effective_value('interval receive') + if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval transmit'): + bfd_peer['tx_interval'] = conf.return_effective_value('interval transmit') + if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval multiplier'): + bfd_peer['multiplier'] = conf.return_effective_value('interval multiplier') + if conf_mode == "proposed" and conf.exists('interval multiplier'): + bfd_peer['multiplier'] = conf.return_value('interval multiplier') + + # Configures the minimal echo receive transmission interval that this system is capable of handling + if conf_mode == "effective" and conf.exists_effective('interval echo-interval'): + bfd_peer['echo_interval'] = conf.return_effective_value('interval echo-interval') + if conf_mode == "proposed" and conf.exists('interval echo-interval'): + bfd_peer['echo_interval'] = conf.return_value('interval echo-interval') + + # Enables or disables the echo transmission mode + if conf_mode == "effective" and conf.exists_effective('echo-mode'): + bfd_peer['echo_mode'] = True + if conf_mode == "proposed" and conf.exists('echo-mode'): + bfd_peer['echo_mode'] = True + + return bfd_peer + +def get_config(): + bfd = 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) + for peer in conf.list_effective_nodes('peer'): + bfd['old_peers'].append(get_bfd_peer_config(peer, "effective")) + + for peer in conf.list_nodes('peer'): + bfd['new_peers'].append(get_bfd_peer_config(peer)) + + # find deleted peers + set_new_peers = set(conf.list_nodes('peer')) + set_old_peers = set(conf.list_effective_nodes('peer')) + bfd['deleted_peers'] = set_old_peers - set_new_peers + + return bfd + +def verify(bfd): + if bfd is None: + return None + + # some variables to use later + conf = Config() + + for peer in bfd['new_peers']: + # IPv6 link local peers require an explicit local address/interface + if is_ipv6_link_local(peer['remote']): + if not (peer['src_if'] and peer['src_addr']): + raise ConfigError('BFD IPv6 link-local peers require explicit local address and interface setting') + + # IPv6 peers require an explicit local address + if is_ipv6(peer['remote']): + if not peer['src_addr']: + raise ConfigError('BFD IPv6 peers require explicit local address setting') + + # multihop require source address + if peer['multihop'] and not peer['src_addr']: + raise ConfigError('Multihop require source address') + + # multihop and echo-mode cannot be used together + if peer['multihop'] and peer['echo_mode']: + raise ConfigError('Multihop and echo-mode cannot be used together') + + # multihop doesn't accept interface names + if peer['multihop'] and peer['src_if']: + raise ConfigError('Multihop and source interface cannot be used together') + + # echo interval can be configured only with enabled echo-mode + if peer['echo_interval'] != '' and not peer['echo_mode']: + raise ConfigError('echo-interval can be configured only with enabled echo-mode') + + # check if we deleted peers are not used in configuration + if conf.exists('protocols bgp'): + bgp_as = conf.list_nodes('protocols bgp')[0] + + # check BGP neighbors + for peer in bfd['deleted_peers']: + if conf.exists('protocols bgp {0} neighbor {1} bfd'.format(bgp_as, peer)): + raise ConfigError('Cannot delete BFD peer {0}: it is used in BGP configuration'.format(peer)) + if conf.exists('protocols bgp {0} neighbor {1} peer-group'.format(bgp_as, peer)): + peer_group = conf.return_value('protocols bgp {0} neighbor {1} peer-group'.format(bgp_as, peer)) + if conf.exists('protocols bgp {0} peer-group {1} bfd'.format(bgp_as, peer_group)): + raise ConfigError('Cannot delete BFD peer {0}: it belongs to BGP peer-group {1} with enabled BFD'.format(peer, peer_group)) + + return None + +def generate(bfd): + if bfd is None: + return None + + render(config_file, 'frr/bfd.frr.tmpl', bfd) + return None + +def apply(bfd): + if bfd is None: + return None + + call("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) + exit(1) |