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protocols_isis.py
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protocols_isis.py
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#!/usr/bin/env python3
#
# Copyright (C) 2020-2022 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 sys import argv
from vyos.config import Config
from vyos.configdict import dict_merge
from vyos.configdict import node_changed
from vyos.configverify import verify_common_route_maps
from vyos.configverify import verify_interface_exists
from vyos.ifconfig import Interface
from vyos.utils.dict import dict_search
from vyos.utils.network import get_interface_config
from vyos.template import render_to_string
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()
vrf = None
if len(argv) > 1:
vrf = argv[1]
base_path = ['protocols', 'isis']
# eqivalent of the C foo ? 'a' : 'b' statement
base = vrf and ['vrf', 'name', vrf, 'protocols', 'isis'] or base_path
isis = conf.get_config_dict(base, key_mangling=('-', '_'),
get_first_key=True,
no_tag_node_value_mangle=True)
# Assign the name of our VRF context. This MUST be done before the return
# statement below, else on deletion we will delete the default instance
# instead of the VRF instance.
if vrf: isis['vrf'] = vrf
# 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:
isis['interface_removed'] = list(interfaces_removed)
# Bail out early if configuration tree does no longer exist. this must
# be done after retrieving the list of interfaces to be removed.
if not conf.exists(base):
isis.update({'deleted' : ''})
return isis
# merge in default values
isis = conf.merge_defaults(isis, recursive=True)
# We also need some additional information from the config, prefix-lists
# and route-maps for instance. They will be used in verify().
#
# XXX: one MUST always call this without the key_mangling() option! See
# vyos.configverify.verify_common_route_maps() for more information.
tmp = conf.get_config_dict(['policy'])
# Merge policy dict into "regular" config dict
isis = dict_merge(tmp, isis)
return isis
def verify(isis):
# bail out early - looks like removal from running config
if not isis or 'deleted' in isis:
return None
if 'net' not in isis:
raise ConfigError('Network entity is mandatory!')
# last byte in IS-IS area address must be 0
tmp = isis['net'].split('.')
if int(tmp[-1]) != 0:
raise ConfigError('Last byte of IS-IS network entity title must always be 0!')
verify_common_route_maps(isis)
# If interface not set
if 'interface' not in isis:
raise ConfigError('Interface used for routing updates is mandatory!')
for interface in isis['interface']:
verify_interface_exists(interface)
# Interface MTU must be >= configured lsp-mtu
mtu = Interface(interface).get_mtu()
area_mtu = isis['lsp_mtu']
# Recommended maximum PDU size = interface MTU - 3 bytes
recom_area_mtu = mtu - 3
if mtu < int(area_mtu) or int(area_mtu) > recom_area_mtu:
raise ConfigError(f'Interface {interface} has MTU {mtu}, ' \
f'current area MTU is {area_mtu}! \n' \
f'Recommended area lsp-mtu {recom_area_mtu} or less ' \
'(calculated on MTU size).')
if 'vrf' in isis:
# If interface specific options are set, we must ensure that the
# interface is bound to our requesting VRF. Due to the VyOS
# priorities the interface is bound to the VRF after creation of
# the VRF itself, and before any routing protocol is configured.
vrf = isis['vrf']
tmp = get_interface_config(interface)
if 'master' not in tmp or tmp['master'] != vrf:
raise ConfigError(f'Interface "{interface}" is not a member of VRF "{vrf}"!')
# If md5 and plaintext-password set at the same time
for password in ['area_password', 'domain_password']:
if password in isis:
if {'md5', 'plaintext_password'} <= set(isis[password]):
tmp = password.replace('_', '-')
raise ConfigError(f'Can use either md5 or plaintext-password for {tmp}!')
# If one param from delay set, but not set others
if 'spf_delay_ietf' in isis:
required_timers = ['holddown', 'init_delay', 'long_delay', 'short_delay', 'time_to_learn']
exist_timers = []
for elm_timer in required_timers:
if elm_timer in isis['spf_delay_ietf']:
exist_timers.append(elm_timer)
exist_timers = set(required_timers).difference(set(exist_timers))
if len(exist_timers) > 0:
raise ConfigError('All types of spf-delay must be configured. Missing: ' + ', '.join(exist_timers).replace('_', '-'))
# If Redistribute set, but level don't set
if 'redistribute' in isis:
proc_level = isis.get('level','').replace('-','_')
for afi in ['ipv4', 'ipv6']:
if afi not in isis['redistribute']:
continue
for proto, proto_config in isis['redistribute'][afi].items():
if 'level_1' not in proto_config and 'level_2' not in proto_config:
raise ConfigError(f'Redistribute level-1 or level-2 should be specified in ' \
f'"protocols isis {process} redistribute {afi} {proto}"!')
for redistr_level, redistr_config in proto_config.items():
if proc_level and proc_level != 'level_1_2' and proc_level != redistr_level:
raise ConfigError(f'"protocols isis {process} redistribute {afi} {proto} {redistr_level}" ' \
f'can not be used with \"protocols isis {process} level {proc_level}\"')
# Segment routing checks
if dict_search('segment_routing.global_block', isis):
g_high_label_value = dict_search('segment_routing.global_block.high_label_value', isis)
g_low_label_value = dict_search('segment_routing.global_block.low_label_value', isis)
# If segment routing global block high or low value is blank, throw error
if not (g_low_label_value or g_high_label_value):
raise ConfigError('Segment routing global-block requires both low and high value!')
# If segment routing global block low value is higher than the high value, throw error
if int(g_low_label_value) > int(g_high_label_value):
raise ConfigError('Segment routing global-block low value must be lower than high value')
if dict_search('segment_routing.local_block', isis):
if dict_search('segment_routing.global_block', isis) == None:
raise ConfigError('Segment routing local-block requires global-block to be configured!')
l_high_label_value = dict_search('segment_routing.local_block.high_label_value', isis)
l_low_label_value = dict_search('segment_routing.local_block.low_label_value', isis)
# If segment routing local-block high or low value is blank, throw error
if not (l_low_label_value or l_high_label_value):
raise ConfigError('Segment routing local-block requires both high and low value!')
# If segment routing local-block low value is higher than the high value, throw error
if int(l_low_label_value) > int(l_high_label_value):
raise ConfigError('Segment routing local-block low value must be lower than high value')
# local-block most live outside global block
global_range = range(int(g_low_label_value), int(g_high_label_value) +1)
local_range = range(int(l_low_label_value), int(l_high_label_value) +1)
# Check for overlapping ranges
if list(set(global_range) & set(local_range)):
raise ConfigError(f'Segment-Routing Global Block ({g_low_label_value}/{g_high_label_value}) '\
f'conflicts with Local Block ({l_low_label_value}/{l_high_label_value})!')
# Check for a blank or invalid value per prefix
if dict_search('segment_routing.prefix', isis):
for prefix, prefix_config in isis['segment_routing']['prefix'].items():
if 'absolute' in prefix_config:
if prefix_config['absolute'].get('value') is None:
raise ConfigError(f'Segment routing prefix {prefix} absolute value cannot be blank.')
elif 'index' in prefix_config:
if prefix_config['index'].get('value') is None:
raise ConfigError(f'Segment routing prefix {prefix} index value cannot be blank.')
# Check for explicit-null and no-php-flag configured at the same time per prefix
if dict_search('segment_routing.prefix', isis):
for prefix, prefix_config in isis['segment_routing']['prefix'].items():
if 'absolute' in prefix_config:
if ("explicit_null" in prefix_config['absolute']) and ("no_php_flag" in prefix_config['absolute']):
raise ConfigError(f'Segment routing prefix {prefix} cannot have both explicit-null '\
f'and no-php-flag configured at the same time.')
elif 'index' in prefix_config:
if ("explicit_null" in prefix_config['index']) and ("no_php_flag" in prefix_config['index']):
raise ConfigError(f'Segment routing prefix {prefix} cannot have both explicit-null '\
f'and no-php-flag configured at the same time.')
# Check for index ranges being larger than the segment routing global block
if dict_search('segment_routing.global_block', isis):
g_high_label_value = dict_search('segment_routing.global_block.high_label_value', isis)
g_low_label_value = dict_search('segment_routing.global_block.low_label_value', isis)
g_label_difference = int(g_high_label_value) - int(g_low_label_value)
if dict_search('segment_routing.prefix', isis):
for prefix, prefix_config in isis['segment_routing']['prefix'].items():
if 'index' in prefix_config:
index_size = isis['segment_routing']['prefix'][prefix]['index']['value']
if int(index_size) > int(g_label_difference):
raise ConfigError(f'Segment routing prefix {prefix} cannot have an '\
f'index base size larger than the SRGB label base.')
# Check for LFA tiebreaker index duplication
if dict_search('fast_reroute.lfa.local.tiebreaker', isis):
comparison_dictionary = {}
for item, item_options in isis['fast_reroute']['lfa']['local']['tiebreaker'].items():
for index, index_options in item_options.items():
for index_value, index_value_options in index_options.items():
if index_value not in comparison_dictionary.keys():
comparison_dictionary[index_value] = [item]
else:
comparison_dictionary[index_value].append(item)
for index, index_length in comparison_dictionary.items():
if int(len(index_length)) > 1:
raise ConfigError(f'LFA index {index} cannot have more than one tiebreaker configured.')
# Check for LFA priority-limit configured multiple times per level
if dict_search('fast_reroute.lfa.local.priority_limit', isis):
comparison_dictionary = {}
for priority, priority_options in isis['fast_reroute']['lfa']['local']['priority_limit'].items():
for level, level_options in priority_options.items():
if level not in comparison_dictionary.keys():
comparison_dictionary[level] = [priority]
else:
comparison_dictionary[level].append(priority)
for level, level_length in comparison_dictionary.items():
if int(len(level_length)) > 1:
raise ConfigError(f'LFA priority-limit on {level.replace("_", "-")} cannot have more than one priority configured.')
# Check for LFA remote prefix list configured with more than one list
if dict_search('fast_reroute.lfa.remote.prefix_list', isis):
if int(len(isis['fast_reroute']['lfa']['remote']['prefix_list'].items())) > 1:
raise ConfigError(f'LFA remote prefix-list has more than one configured. Cannot have more than one configured.')
return None
def generate(isis):
if not isis or 'deleted' in isis:
return None
isis['frr_isisd_config'] = render_to_string('frr/isisd.frr.j2', isis)
return None
def apply(isis):
isis_daemon = 'isisd'
# Save original configuration prior to starting any commit actions
frr_cfg = frr.FRRConfig()
# Generate empty helper string which can be ammended to FRR commands, it
# will be either empty (default VRF) or contain the "vrf <name" statement
vrf = ''
if 'vrf' in isis:
vrf = ' vrf ' + isis['vrf']
frr_cfg.load_configuration(isis_daemon)
frr_cfg.modify_section(f'^router isis VyOS{vrf}', stop_pattern='^exit', remove_stop_mark=True)
for key in ['interface', 'interface_removed']:
if key not in isis:
continue
for interface in isis[key]:
frr_cfg.modify_section(f'^interface {interface}', stop_pattern='^exit', remove_stop_mark=True)
if 'frr_isisd_config' in isis:
frr_cfg.add_before(frr.default_add_before, isis['frr_isisd_config'])
frr_cfg.commit_configuration(isis_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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