diff --git a/src/conf_mode/interfaces-vxlan.py b/src/conf_mode/interfaces-vxlan.py index 9a6d72772..c035557f0 100755 --- a/src/conf_mode/interfaces-vxlan.py +++ b/src/conf_mode/interfaces-vxlan.py @@ -1,119 +1,128 @@ #!/usr/bin/env python3 # # Copyright (C) 2019-2020 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/>. import os from sys import exit from netifaces import interfaces from vyos.config import Config from vyos.configdict import get_interface_dict from vyos.configverify import verify_address from vyos.configverify import verify_bridge_delete from vyos.configverify import verify_mtu_ipv6 from vyos.configverify import verify_source_interface -from vyos.ifconfig import VXLANIf, Interface +from vyos.ifconfig import Interface +from vyos.ifconfig import VXLANIf +from vyos.template import is_ipv6 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', 'vxlan'] vxlan = get_interface_dict(conf, base) return vxlan def verify(vxlan): if 'deleted' in vxlan: verify_bridge_delete(vxlan) return None if int(vxlan['mtu']) < 1500: print('WARNING: RFC7348 recommends VXLAN tunnels preserve a 1500 byte MTU') if 'group' in vxlan: if 'source_interface' not in vxlan: raise ConfigError('Multicast VXLAN requires an underlaying interface ') verify_source_interface(vxlan) if not any(tmp in ['group', 'remote', 'source_address'] for tmp in vxlan): raise ConfigError('Group, remote or source-address must be configured') if 'vni' not in vxlan: raise ConfigError('Must configure VNI for VXLAN') if 'source_interface' in vxlan: - # VXLAN adds a 50 byte overhead - we need to check the underlaying MTU - # if our configured MTU is at least 50 bytes less + # VXLAN adds at least an overhead of 50 byte - we need to check the + # underlaying device if our VXLAN package is not going to be fragmented! + vxlan_overhead = 50 + if 'source_address' in vxlan and is_ipv6(vxlan['source_address']): + # IPv6 adds an extra 20 bytes overhead because the IPv6 header is 20 + # bytes larger than the IPv4 header - assuming no extra options are + # in use. + vxlan_overhead += 20 + lower_mtu = Interface(vxlan['source_interface']).get_mtu() - if lower_mtu < (int(vxlan['mtu']) + 50): - raise ConfigError('VXLAN has a 50 byte overhead, underlaying device ' \ - f'MTU is to small ({lower_mtu} bytes)') + if lower_mtu < (int(vxlan['mtu']) + vxlan_overhead): + raise ConfigError(f'Underlaying device MTU is to small ({lower_mtu} '\ + f'bytes) for VXLAN overhead ({vxlan_overhead} bytes!)') verify_mtu_ipv6(vxlan) verify_address(vxlan) return None def generate(vxlan): return None def apply(vxlan): # Check if the VXLAN interface already exists if vxlan['ifname'] in interfaces(): v = VXLANIf(vxlan['ifname']) # VXLAN is super picky and the tunnel always needs to be recreated, # thus we can simply always delete it first. v.remove() if 'deleted' not in vxlan: # This is a special type of interface which needs additional parameters # when created using iproute2. Instead of passing a ton of arguments, # use a dictionary provided by the interface class which holds all the # options necessary. conf = VXLANIf.get_config() # Assign VXLAN instance configuration parameters to config dict for tmp in ['vni', 'group', 'source_address', 'source_interface', 'remote', 'port']: if tmp in vxlan: conf[tmp] = vxlan[tmp] # Finally create the new interface v = VXLANIf(vxlan['ifname'], **conf) v.update(vxlan) return None if __name__ == '__main__': try: c = get_config() verify(c) generate(c) apply(c) except ConfigError as e: print(e) exit(1)