#!/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 . 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_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())}) 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 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) 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'] 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)