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#!/usr/bin/env python3
#
# Copyright (C) 2023 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 vyos.config import Config
from vyos.configdict import node_changed
from vyos.template import render_to_string
from vyos.utils.dict import dict_search
from vyos.utils.system import sysctl_write
from vyos import ConfigError
from vyos import frr
from vyos import airbag
airbag.enable()
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
base = ['protocols', 'segment-routing']
sr = conf.get_config_dict(base, key_mangling=('-', '_'),
get_first_key=True,
no_tag_node_value_mangle=True,
with_recursive_defaults=True)
# FRR has VRF support for different routing daemons. As interfaces belong
# to VRFs - or the global VRF, we need to check for changed interfaces so
# that they will be properly rendered for the FRR config. Also this eases
# removal of interfaces from the running configuration.
interfaces_removed = node_changed(conf, base + ['interface'])
if interfaces_removed:
sr['interface_removed'] = list(interfaces_removed)
import pprint
pprint.pprint(sr)
return sr
def verify(sr):
if 'srv6' in sr:
srv6_enable = False
if 'interface' in sr:
for interface, interface_config in sr['interface'].items():
if 'srv6' in interface_config:
srv6_enable = True
break
if not srv6_enable:
raise ConfigError('SRv6 should be enabled on at least one interface!')
return None
def generate(sr):
if not sr:
return None
sr['new_frr_config'] = render_to_string('frr/zebra.segment_routing.frr.j2', sr)
return None
def apply(sr):
zebra_daemon = 'zebra'
if 'interface_removed' in sr:
for interface in sr['interface_removed']:
# Disable processing of IPv6-SR packets
sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0')
if 'interface' in sr:
for interface, interface_config in sr['interface'].items():
# Accept or drop SR-enabled IPv6 packets on this interface
if 'srv6' in interface_config:
sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '1')
# Define HMAC policy for ingress SR-enabled packets on this interface
# It's a redundant check as HMAC has a default value - but better safe
# then sorry
tmp = dict_search('srv6.hmac', interface_config)
if tmp == 'accept':
sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '0')
elif tmp == 'drop':
sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '1')
elif tmp == 'ignore':
sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '-1')
else:
sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0')
# Save original configuration prior to starting any commit actions
frr_cfg = frr.FRRConfig()
frr_cfg.load_configuration(zebra_daemon)
frr_cfg.modify_section(r'^segment-routing')
if 'new_frr_config' in sr:
frr_cfg.add_before(frr.default_add_before, sr['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)
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