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interfaces-tunnel.py
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interfaces-tunnel.py
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#!/usr/bin/env python3
#
# Copyright (C) 2018-2022 yOS 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 netifaces import interfaces
from vyos.config import Config
from vyos.configdict import get_interface_dict
from vyos.configdict import leaf_node_changed
from vyos.configverify import verify_address
from vyos.configverify import verify_bridge_delete
from vyos.configverify import verify_interface_exists
from vyos.configverify import verify_mtu_ipv6
from vyos.configverify import verify_redirect
from vyos.configverify import verify_vrf
from vyos.configverify import verify_tunnel
from vyos.ifconfig import Interface
from vyos.ifconfig import Section
from vyos.ifconfig import TunnelIf
from vyos.util import get_interface_config
from vyos.util import dict_search
from vyos import ConfigError
from vyos import airbag
airbag.enable()
def get_config(config=None):
"""
Retrive CLI config as dictionary. Dictionary can never be empty, as at least
the interface name will be added or a deleted flag
"""
if config:
conf = config
else:
conf = Config()
base = ['interfaces', 'tunnel']
tunnel = get_interface_dict(conf, base)
if 'deleted' not in tunnel:
tmp = leaf_node_changed(conf, ['encapsulation'])
if tmp: tunnel.update({'encapsulation_changed': {}})
# We also need to inspect other configured tunnels as there are Kernel
# restrictions where we need to comply. E.g. GRE tunnel key can't be used
# twice, or with multiple GRE tunnels to the same location we must specify
# a GRE key
conf.set_level(base)
tunnel['other_tunnels'] = conf.get_config_dict([], key_mangling=('-', '_'),
get_first_key=True,
no_tag_node_value_mangle=True)
# delete our own instance from this dict
ifname = tunnel['ifname']
del tunnel['other_tunnels'][ifname]
# if only one tunnel is present on the system, no need to keep this key
if len(tunnel['other_tunnels']) == 0:
del tunnel['other_tunnels']
# We must check if our interface is configured to be a DMVPN member
nhrp_base = ['protocols', 'nhrp', 'tunnel']
conf.set_level(nhrp_base)
nhrp = conf.get_config_dict([], key_mangling=('-', '_'), get_first_key=True)
if nhrp: tunnel.update({'nhrp' : list(nhrp.keys())})
if 'encapsulation' in tunnel and tunnel['encapsulation'] not in ['erspan', 'ip6erspan']:
del tunnel['parameters']['erspan']
return tunnel
def verify(tunnel):
if 'deleted' in tunnel:
verify_bridge_delete(tunnel)
if 'nhrp' in tunnel and tunnel['ifname'] in tunnel['nhrp']:
raise ConfigError('Tunnel used for NHRP, it can not be deleted!')
return None
verify_tunnel(tunnel)
if tunnel['encapsulation'] in ['erspan', 'ip6erspan']:
if dict_search('parameters.ip.key', tunnel) == None:
raise ConfigError('ERSPAN requires ip key parameter!')
# this is a default field
ver = int(tunnel['parameters']['erspan']['version'])
if ver == 1:
if 'hw_id' in tunnel['parameters']['erspan']:
raise ConfigError('ERSPAN version 1 does not support hw-id!')
if 'direction' in tunnel['parameters']['erspan']:
raise ConfigError('ERSPAN version 1 does not support direction!')
elif ver == 2:
if 'idx' in tunnel['parameters']['erspan']:
raise ConfigError('ERSPAN version 2 does not index parameter!')
if 'direction' not in tunnel['parameters']['erspan']:
raise ConfigError('ERSPAN version 2 requires direction to be set!')
# If tunnel source is any and gre key is not set
interface = tunnel['ifname']
if tunnel['encapsulation'] in ['gre'] and \
dict_search('source_address', tunnel) == '0.0.0.0' and \
dict_search('parameters.ip.key', tunnel) == None:
raise ConfigError(f'"parameters ip key" must be set for {interface} when '\
'encapsulation is GRE!')
gre_encapsulations = ['gre', 'gretap']
if tunnel['encapsulation'] in gre_encapsulations and 'other_tunnels' in tunnel:
# Check pairs tunnel source-address/encapsulation/key with exists tunnels.
# Prevent the same key for 2 tunnels with same source-address/encap. T2920
for o_tunnel, o_tunnel_conf in tunnel['other_tunnels'].items():
# no match on encapsulation - bail out
our_encapsulation = tunnel['encapsulation']
their_encapsulation = o_tunnel_conf['encapsulation']
if our_encapsulation in gre_encapsulations and their_encapsulation \
not in gre_encapsulations:
continue
our_address = dict_search('source_address', tunnel)
our_key = dict_search('parameters.ip.key', tunnel)
their_address = dict_search('source_address', o_tunnel_conf)
their_key = dict_search('parameters.ip.key', o_tunnel_conf)
if our_key != None:
if their_address == our_address and their_key == our_key:
raise ConfigError(f'Key "{our_key}" for source-address "{our_address}" ' \
f'is already used for tunnel "{tunnel_if}"!')
else:
our_source_if = dict_search('source_interface', tunnel)
their_source_if = dict_search('source_interface', o_tunnel_conf)
our_remote = dict_search('remote', tunnel)
their_remote = dict_search('remote', o_tunnel_conf)
# If no IP GRE key is defined we can not have more then one GRE tunnel
# bound to any one interface/IP address and the same remote. This will
# result in a OS PermissionError: add tunnel "gre0" failed: File exists
if (their_address == our_address or our_source_if == their_source_if) and \
our_remote == their_remote:
raise ConfigError(f'Missing required "ip key" parameter when '\
'running more then one GRE based tunnel on the '\
'same source-interface/source-address')
# Keys are not allowed with ipip and sit tunnels
if tunnel['encapsulation'] in ['ipip', 'sit']:
if dict_search('parameters.ip.key', tunnel) != None:
raise ConfigError('Keys are not allowed with ipip and sit tunnels!')
verify_mtu_ipv6(tunnel)
verify_address(tunnel)
verify_vrf(tunnel)
verify_redirect(tunnel)
if 'source_interface' in tunnel:
verify_interface_exists(tunnel['source_interface'])
# TTL != 0 and nopmtudisc are incompatible, parameters and ip use default
# values, thus the keys are always present.
if dict_search('parameters.ip.no_pmtu_discovery', tunnel) != None:
if dict_search('parameters.ip.ttl', tunnel) != '0':
raise ConfigError('Disabled PMTU requires TTL set to "0"!')
if tunnel['encapsulation'] in ['ipip6', 'ip6ip6', 'ip6gre']:
raise ConfigError('Can not disable PMTU discovery for given encapsulation')
if dict_search('parameters.ip.ignore_df', tunnel) != None:
if tunnel['encapsulation'] not in ['gretap']:
raise ConfigError('Option ignore-df can only be used on GRETAP tunnels!')
if dict_search('parameters.ip.no_pmtu_discovery', tunnel) == None:
raise ConfigError('Option ignore-df requires path MTU discovery to be disabled!')
def generate(tunnel):
return None
def apply(tunnel):
interface = tunnel['ifname']
# If a gretap tunnel is already existing we can not "simply" change local or
# remote addresses. This returns "Operation not supported" by the Kernel.
# There is no other solution to destroy and recreate the tunnel.
encap = ''
remote = ''
tmp = get_interface_config(interface)
if tmp:
encap = dict_search('linkinfo.info_kind', tmp)
remote = dict_search('linkinfo.info_data.remote', tmp)
if ('deleted' in tunnel or 'encapsulation_changed' in tunnel or encap in
['gretap', 'ip6gretap', 'erspan', 'ip6erspan'] or remote in ['any']):
if interface in interfaces():
tmp = Interface(interface)
tmp.remove()
if 'deleted' in tunnel:
return None
tun = TunnelIf(**tunnel)
tun.update(tunnel)
return None
if __name__ == '__main__':
try:
c = get_config()
generate(c)
verify(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)

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