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#!/usr/bin/env python3
#
# Copyright (C) 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/>.
from sys import exit
from vyos.config import Config
from vyos.util import call
from vyos.util import dict_search
from vyos.template import render
from vyos.template import render_to_string
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', 'nbgp']
bgp = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True)
# XXX: any reason we can not move this into the FRR template?
# we shall not call vtysh directly, especially not in get_config()
if not conf.exists(base):
bgp = {}
call('vtysh -c \"conf t\" -c \"no ip protocol bgp\" ')
if not conf.exists(base + ['route-map']):
call('vtysh -c \"conf t\" -c \"no ip protocol bgp\" ')
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 can be defined!')
for asn, asn_config in bgp.items():
# Common verification for both peer-group and neighbor statements
for neigh in ['neighbor', 'peer_group']:
# bail out early if there is no neighbor or peer-group statement
# this also saves one indention level
if neigh not in asn_config:
continue
for neighbor, config in asn_config[neigh].items():
if 'remote_as' not in config and 'peer_group' not in config:
raise ConfigError(f'BGP remote-as must be specified for "{neighbor}"!')
if 'remote_as' in config and 'peer_group' in config:
raise ConfigError(f'BGP peer-group member "{neighbor}" cannot override remote-as of peer-group!')
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_cfg['original_config'] = frr.get_configuration(daemon='bgpd')
frr_cfg['modified_config'] = frr.replace_section(frr_cfg['original_config'], bgp['new_frr_config'], from_re='router bgp .*')
# 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')
# FRR mark configuration will test for syntax errors and throws an
# exception if any syntax errors is detected
frr.mark_configuration(frr_cfg['modified_config'])
# Commit resulting configuration to FRR, this will throw CommitError
# on failure
frr.reload_configuration(frr_cfg['modified_config'], daemon='bgpd')
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
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