"""BGP implementation for FAUCET."""
# Copyright (C) 2013 Nippon Telegraph and Telephone Corporation.
# Copyright (C) 2015 Brad Cowie, Christopher Lorier and Joe Stringer.
# Copyright (C) 2015 Research and Education Advanced Network New Zealand Ltd.
# Copyright (C) 2015--2018 The Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import ipaddress
import eventlet
eventlet.monkey_patch()
from ryu.lib import hub # pylint: disable=wrong-import-position
from beka.beka import Beka # pylint: disable=wrong-import-position
[docs]class FaucetBgp(object):
"""Wrapper for Ryu BGP speaker."""
def __init__(self, logger, metrics, send_flow_msgs):
self.logger = logger
self.metrics = metrics
self._send_flow_msgs = send_flow_msgs
self._dp_bgp_speakers = {}
self._valves = None
@staticmethod
def _neighbor_states(bgp_speaker):
"""Return state of each neighbor for a BGP speaker as a list."""
neighbor_states = []
if bgp_speaker is not None:
neighbor_states = bgp_speaker.neighbor_states()
return neighbor_states
def _bgp_up_handler(self, remote_ip, remote_as):
self.logger.info('BGP peer router ID %s AS %s up' % (remote_ip, remote_as))
def _bgp_down_handler(self, remote_ip, remote_as):
self.logger.info('BGP peer router ID %s AS %s down' % (remote_ip, remote_as))
def _bgp_route_handler(self, path_change, dp_id, vlan_vid):
"""Handle a BGP change event.
Args:
path_change (ryu.services.protocols.bgp.bgpspeaker.EventPrefix): path change
dp_id (int): Datapath ID this path change was received for.
vlan_vid (vlan_vid): VLAN VID this path change was received for.
"""
if not self._valves or dp_id not in self._valves:
return
valve = self._valves[dp_id]
if not vlan_vid in valve.dp.vlans:
return
vlan = valve.dp.vlans[vlan_vid]
prefix = ipaddress.ip_network(str(path_change.prefix))
if path_change.next_hop:
nexthop = ipaddress.ip_address(str(path_change.next_hop))
if vlan.is_faucet_vip(nexthop):
self.logger.error(
'BGP nexthop %s for prefix %s cannot be us',
nexthop, prefix)
return
if vlan.ip_in_vip_subnet(nexthop) is None:
self.logger.error(
'BGP nexthop %s for prefix %s is not a connected network',
nexthop, prefix)
return
flowmods = []
if path_change.is_withdraw:
self.logger.info(
'BGP withdraw %s', prefix)
flowmods = valve.del_route(vlan, prefix)
else:
self.logger.info(
'BGP add %s nexthop %s', prefix, nexthop)
flowmods = valve.add_route(vlan, nexthop, prefix)
if flowmods:
self._send_flow_msgs(valve, flowmods)
@staticmethod
def _bgp_vlans(valves):
bgp_vlans = set()
if valves:
for valve in list(valves.values()):
for vlan in valve.dp.bgp_vlans():
bgp_vlans.add(vlan)
return bgp_vlans
@staticmethod
def _vlan_prefixes_by_ipv(vlan, ipv):
vlan_prefixes = []
for faucet_vip in vlan.faucet_vips_by_ipv(ipv):
vlan_prefixes.append((str(faucet_vip), str(faucet_vip.ip)))
routes = vlan.routes_by_ipv(ipv)
for ip_dst, ip_gw in list(routes.items()):
vlan_prefixes.append((str(ip_dst), str(ip_gw)))
return vlan_prefixes
def _create_bgp_speaker_for_vlan(self, vlan, dp_id, vlan_vid, ipv):
"""Set up BGP speaker for an individual VLAN if required.
Args:
vlan (valve VLAN): VLAN for BGP speaker.
dp_id (int): Datapath ID for BGP speaker.
vlan_vid (vlan_vid): VLAN VID for BGP speaker.
Returns:
ryu.services.protocols.bgp.bgpspeaker.BGPSpeaker: BGP speaker.
"""
handler = lambda x: self._bgp_route_handler(x, dp_id, vlan_vid)
if len(vlan.bgp_server_addresses_by_ipv(ipv)) > 1:
self.logger.warning(
'Only one server per IPv per vlan supported')
server_address = sorted(vlan.bgp_server_addresses_by_ipv(ipv))[0]
beka = Beka(
local_address=str(server_address),
bgp_port=vlan.bgp_port,
local_as=vlan.bgp_as,
router_id=vlan.bgp_routerid,
peer_up_handler=self._bgp_up_handler,
peer_down_handler=self._bgp_down_handler,
route_handler=handler,
error_handler=self.logger.warning
)
for ip_dst, ip_gw in self._vlan_prefixes_by_ipv(vlan, ipv):
beka.add_route(prefix=str(ip_dst), next_hop=str(ip_gw))
for bgp_neighbor_address in vlan.bgp_neighbor_addresses_by_ipv(ipv):
beka.add_neighbor(
connect_mode="passive",
peer_ip=str(bgp_neighbor_address),
peer_as=vlan.bgp_neighbor_as
)
hub.spawn(beka.run)
return beka
[docs] def shutdown_bgp_speakers(self):
"""Shutdown any active BGP speakers."""
for vlan_bgp_speakers_by_ipv in list(self._dp_bgp_speakers.values()):
for vlan_bgp_speakers in list(vlan_bgp_speakers_by_ipv.values()):
for bgp_speaker in list(vlan_bgp_speakers.values()):
bgp_speaker.shutdown()
self._dp_bgp_speakers = {}
[docs] def reset(self, valves):
"""Set up a BGP speaker for every VLAN that requires it."""
# TODO: port status changes should cause us to withdraw a route.
# TODO: BGP speaker library does not cleanly handle del/add of same peer
# TODO: BGP speaker can listen only on one address family at once
# TODO: Ryu BGP supports only one speaker
# (https://sourceforge.net/p/ryu/mailman/message/32699012/)
# TODO: Ryu BGP cannot be restarted cleanly (so config cannot change at runtime)
self._valves = valves
if self._dp_bgp_speakers:
self.logger.warning(
'not updating existing BGP speaker, runtime BGP changes not supported')
return
bgp_vlans = self._bgp_vlans(self._valves)
if not bgp_vlans:
return
if len(bgp_vlans) > 1:
self.logger.warning(
'only one BGP VLAN currently supported')
bgp_vlan = sorted(bgp_vlans)[0]
dp_id = bgp_vlan.dp_id
vlan_vid = bgp_vlan.vid
self._dp_bgp_speakers[dp_id] = {}
for ipv in bgp_vlan.bgp_ipvs():
self._dp_bgp_speakers[dp_id][ipv] = {
vlan_vid: self._create_bgp_speaker_for_vlan(bgp_vlan, dp_id, vlan_vid, ipv)}
[docs] def update_metrics(self, _now):
"""Update BGP metrics."""
for dp_id, bgp_speakers_by_ipv in list(self._dp_bgp_speakers.items()):
valve = self._valves[dp_id]
for ipv, bgp_speakers in list(bgp_speakers_by_ipv.items()):
for vlan_vid, bgp_speaker in list(bgp_speakers.items()):
# TODO: VLAN deconfigured, online reconfiguration while BGP active not supported.
if vlan_vid not in valve.dp.vlans:
continue
vlan = valve.dp.vlans[vlan_vid]
neighbor_states = self._neighbor_states(bgp_speaker)
for neighbor, neighbor_state in neighbor_states:
neighbor_labels = dict(
valve.base_prom_labels, vlan=vlan.vid, neighbor=neighbor)
self.metrics.bgp_neighbor_uptime_seconds.labels( # pylint: disable=no-member
**neighbor_labels).set(neighbor_state['info']['uptime'])
self.metrics.bgp_neighbor_routes.labels( # pylint: disable=no-member
**dict(neighbor_labels, ipv=ipv)).set(vlan.route_count_by_ipv(ipv))