text: #!/usr/bin/env python
  # Copyright 2012 Cisco Systems, Inc.
  # All Rights Reserved.
  #
  #    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.
  #
  #
  # Performs per host Linux Bridge configuration for Neutron.
  # Based on the structure of the OpenVSwitch agent in the
  # Neutron OpenVSwitch Plugin.
  
  import sys
  
  import netaddr
  from neutron_lib.agent import topics
  from neutron_lib import constants
  from neutron_lib import exceptions
  from neutron_lib.plugins import utils as plugin_utils
  from neutron_lib.utils import helpers
  from oslo_config import cfg
  from oslo_log import log as logging
  import oslo_messaging
  from oslo_service import service
  from oslo_utils import excutils
  from six import moves
  
  from neutron.agent.linux import bridge_lib
  from neutron.agent.linux import ip_lib
  from neutron.api.rpc.handlers import securitygroups_rpc as sg_rpc
  from neutron.common import config as common_config
  from neutron.common import profiler as setup_profiler
  from neutron.common import utils
  from neutron.conf.agent import common as agent_config
  from neutron.conf import service as service_conf
  from neutron.plugins.ml2.drivers.agent import _agent_manager_base as amb
  from neutron.plugins.ml2.drivers.agent import _common_agent as ca
  from neutron.plugins.ml2.drivers.agent import config as cagt_config  # noqa
  from neutron.plugins.ml2.drivers.l2pop.rpc_manager \
      import l2population_rpc as l2pop_rpc
  from neutron.plugins.ml2.drivers.linuxbridge.agent import arp_protect
  from neutron.plugins.ml2.drivers.linuxbridge.agent.common import config  # noqa
  from neutron.plugins.ml2.drivers.linuxbridge.agent.common \
      import constants as lconst
  from neutron.plugins.ml2.drivers.linuxbridge.agent.common \
      import utils as lb_utils
  from neutron.plugins.ml2.drivers.linuxbridge.agent import \
      linuxbridge_agent_extension_api as agent_extension_api
  from neutron.plugins.ml2.drivers.linuxbridge.agent \
      import linuxbridge_capabilities
  
  
  LOG = logging.getLogger(__name__)
  
  LB_AGENT_BINARY = 'neutron-linuxbridge-agent'
  BRIDGE_NAME_PREFIX = "brq"
  MAX_VLAN_POSTFIX_LEN = 5
  VXLAN_INTERFACE_PREFIX = "vxlan-"
  
  IPTABLES_DRIVERS = [
      'iptables',
      'iptables_hybrid',
      'neutron.agent.linux.iptables_firewall.IptablesFirewallDriver',
      'neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver'
  ]
  
  
  class LinuxBridgeManager(amb.CommonAgentManagerBase):
      def __init__(self, bridge_mappings, interface_mappings):
          super(LinuxBridgeManager, self).__init__()
          self.bridge_mappings = bridge_mappings
          self.interface_mappings = interface_mappings
          self.validate_interface_mappings()
          self.validate_bridge_mappings()
          self.ip = ip_lib.IPWrapper()
          self.agent_api = None
          # VXLAN related parameters:
          self.local_ip = cfg.CONF.VXLAN.local_ip
          self.vxlan_mode = lconst.VXLAN_NONE
          if cfg.CONF.VXLAN.enable_vxlan:
              device = self.get_local_ip_device()
              self.validate_vxlan_group_with_local_ip()
              self.local_int = device.name
              self.check_vxlan_support()
  
      def validate_interface_mappings(self):
          for physnet, interface in self.interface_mappings.items():
              if not ip_lib.device_exists(interface):
                  LOG.error("Interface %(intf)s for physical network %(net)s"
                            " does not exist. Agent terminated!",
                            {'intf': interface, 'net': physnet})
                  sys.exit(1)
  
      def validate_bridge_mappings(self):
          for physnet, bridge in self.bridge_mappings.items():
              if not ip_lib.device_exists(bridge):
                  LOG.error("Bridge %(brq)s for physical network %(net)s"
                            " does not exist. Agent terminated!",
                            {'brq': bridge, 'net': physnet})
                  sys.exit(1)
  
      def _is_valid_multicast_range(self, mrange):
          try:
              addr, vxlan_min, vxlan_max = mrange.split(':')
              if int(vxlan_min) > int(vxlan_max):
                  raise ValueError()
              try:
                  local_ver = netaddr.IPAddress(self.local_ip).version
                  n_addr = netaddr.IPAddress(addr)
                  if not n_addr.is_multicast() or n_addr.version != local_ver:
                      raise ValueError()
              except netaddr.core.AddrFormatError:
                  raise ValueError()
          except ValueError:
              return False
          return True
  
      def validate_vxlan_group_with_local_ip(self):
          for r in cfg.CONF.VXLAN.multicast_ranges:
              if not self._is_valid_multicast_range(r):
                  LOG.error("Invalid multicast_range %(r)s. Must be in "
                            "<multicast address>:<vni_min>:<vni_max> format and "
                            "addresses must be in the same family as local IP "
                            "%(loc)s.", {'r': r, 'loc': self.local_ip})
                  sys.exit(1)
          if not cfg.CONF.VXLAN.vxlan_group:
              return
          try:
              ip_addr = netaddr.IPAddress(self.local_ip)
              # Ensure the configured group address/range is valid and multicast
              group_net = netaddr.IPNetwork(cfg.CONF.VXLAN.vxlan_group)
              if not group_net.is_multicast():
                  raise ValueError()
              if not ip_addr.version == group_net.version:
                  raise ValueError()
          except (netaddr.core.AddrFormatError, ValueError):
              LOG.error("Invalid VXLAN Group: %(group)s, must be an address "
                        "or network (in CIDR notation) in a multicast "
                        "range of the same address family as local_ip: "
                        "%(ip)s",
                        {'group': cfg.CONF.VXLAN.vxlan_group,
                         'ip': self.local_ip})
              sys.exit(1)
  
      def get_local_ip_device(self):
          """Return the device with local_ip on the host."""
          device = self.ip.get_device_by_ip(self.local_ip)
          if not device:
              LOG.error("Tunneling cannot be enabled without the local_ip "
                        "bound to an interface on the host. Please "
                        "configure local_ip %s on the host interface to "
                        "be used for tunneling and restart the agent.",
                        self.local_ip)
              sys.exit(1)
          return device
  
      @staticmethod
      def get_bridge_name(network_id):
          if not network_id:
              LOG.warning("Invalid Network ID, will lead to incorrect "
                          "bridge name")
          bridge_name = BRIDGE_NAME_PREFIX + \
              network_id[:lconst.RESOURCE_ID_LENGTH]
          return bridge_name
  
      @staticmethod
      def get_subinterface_name(physical_interface, vlan_id):
          if not vlan_id:
              LOG.warning("Invalid VLAN ID, will lead to incorrect "
                          "subinterface name")
          vlan_postfix = '.%s' % vlan_id
  
          # For the vlan subinterface name prefix we use:
          # * the physical_interface, if len(physical_interface) +
          #   len(vlan_postifx) <= 15 for backward compatibility reasons
          #   Example: physical_interface = eth0
          #            prefix = eth0.1
          #            prefix = eth0.1111
          #
          # * otherwise a unique hash per physical_interface to help debugging
          #   Example: physical_interface = long_interface
          #            prefix = longHASHED.1
          #            prefix = longHASHED.1111
          #
          # Remark: For some physical_interface values, the used prefix can be
          # both, the physical_interface itself or a hash, depending
          # on the vlan_postfix length.
          # Example: physical_interface = mix_interface
          #          prefix = mix_interface.1 (backward compatible)
          #          prefix = mix_iHASHED.1111
          if (len(physical_interface) + len(vlan_postfix) >
                  constants.DEVICE_NAME_MAX_LEN):
              physical_interface = plugin_utils.get_interface_name(
                  physical_interface, max_len=(constants.DEVICE_NAME_MAX_LEN -
                                               MAX_VLAN_POSTFIX_LEN))
          return "%s%s" % (physical_interface, vlan_postfix)
  
      @staticmethod
      def get_tap_device_name(interface_id):
          return lb_utils.get_tap_device_name(interface_id)
  
      @staticmethod
      def get_vxlan_device_name(segmentation_id):
          if 0 <= int(segmentation_id) <= constants.MAX_VXLAN_VNI:
              return VXLAN_INTERFACE_PREFIX + str(segmentation_id)
          else:
              LOG.warning("Invalid Segmentation ID: %s, will lead to "
                          "incorrect vxlan device name", segmentation_id)
  
      @staticmethod
      def _match_multicast_range(segmentation_id):
          for mrange in cfg.CONF.VXLAN.multicast_ranges:
              addr, vxlan_min, vxlan_max = mrange.split(':')
              if int(vxlan_min) <= segmentation_id <= int(vxlan_max):
                  return addr
  
      def get_vxlan_group(self, segmentation_id):
          mcast_addr = self._match_multicast_range(segmentation_id)
          if mcast_addr:
              net = netaddr.IPNetwork(mcast_addr)
          else:
              net = netaddr.IPNetwork(cfg.CONF.VXLAN.vxlan_group)
          # Map the segmentation ID to (one of) the group address(es)
          return str(net.network +
                     (int(segmentation_id) & int(net.hostmask)))
  
      def get_deletable_bridges(self):
          bridge_list = bridge_lib.get_bridge_names()
          bridges = {b for b in bridge_list if b.startswith(BRIDGE_NAME_PREFIX)}
          bridges.difference_update(self.bridge_mappings.values())
          return bridges
  
      @staticmethod
      def get_tap_devices_count(bridge_name):
          if_list = bridge_lib.BridgeDevice(bridge_name).get_interfaces()
          return len([interface for interface in if_list if
                      interface.startswith(constants.TAP_DEVICE_PREFIX)])
  
      def ensure_vlan_bridge(self, network_id, phy_bridge_name,
                             physical_interface, vlan_id):
          """Create a vlan and bridge unless they already exist."""
          interface = self.ensure_vlan(physical_interface, vlan_id)
          if phy_bridge_name:
              return self.ensure_bridge(phy_bridge_name)
          else:
              bridge_name = self.get_bridge_name(network_id)
              if self.ensure_bridge(bridge_name, interface):
                  return interface
  
      def ensure_vxlan_bridge(self, network_id, segmentation_id, mtu):
          """Create a vxlan and bridge unless they already exist."""
          interface = self.ensure_vxlan(segmentation_id, mtu)
          if not interface:
              LOG.error("Failed creating vxlan interface for "
                        "%(segmentation_id)s",
                        {'segmentation_id': segmentation_id})
              return
          bridge_name = self.get_bridge_name(network_id)
          self.ensure_bridge(bridge_name, interface, update_interface=False)
          return interface
  
      def get_interface_details(self, interface, ip_version):
          device = self.ip.device(interface)
          ips = device.addr.list(scope='global',
                                 ip_version=ip_version)
  
          # Update default gateway if necessary
          gateway = device.route.get_gateway(scope='global',
                                             ip_version=ip_version)
          return ips, gateway
  
      def ensure_flat_bridge(self, network_id, phy_bridge_name,
                             physical_interface):
          """Create a non-vlan bridge unless it already exists."""
          if phy_bridge_name:
              return self.ensure_bridge(phy_bridge_name)
          else:
              bridge_name = self.get_bridge_name(network_id)
              if self.ensure_bridge(bridge_name, physical_interface):
                  return physical_interface
  
      def ensure_local_bridge(self, network_id, phy_bridge_name):
          """Create a local bridge unless it already exists."""
          if phy_bridge_name:
              bridge_name = phy_bridge_name
          else:
              bridge_name = self.get_bridge_name(network_id)
          return self.ensure_bridge(bridge_name)
  
      def ensure_vlan(self, physical_interface, vlan_id):
          """Create a vlan unless it already exists."""
          interface = self.get_subinterface_name(physical_interface, vlan_id)
          if not ip_lib.device_exists(interface):
              LOG.debug("Creating subinterface %(interface)s for "
                        "VLAN %(vlan_id)s on interface "
                        "%(physical_interface)s",
                        {'interface': interface, 'vlan_id': vlan_id,
                         'physical_interface': physical_interface})
              try:
                  int_vlan = self.ip.add_vlan(interface, physical_interface,
                                              vlan_id)
              except RuntimeError:
                  with excutils.save_and_reraise_exception() as ctxt:
                      if ip_lib.vlan_in_use(vlan_id):
                          ctxt.reraise = False
                          LOG.error("Unable to create VLAN interface for "
                                    "VLAN ID %s because it is in use by "
                                    "another interface.", vlan_id)
                          return
              int_vlan.disable_ipv6()
              int_vlan.link.set_up()
              LOG.debug("Done creating subinterface %s", interface)
          return interface
  
      def ensure_vxlan(self, segmentation_id, mtu=None):
          """Create a vxlan unless it already exists."""
          interface = self.get_vxlan_device_name(segmentation_id)
          if not ip_lib.device_exists(interface):
              LOG.debug("Creating vxlan interface %(interface)s for "
                        "VNI %(segmentation_id)s",
                        {'interface': interface,
                         'segmentation_id': segmentation_id})
              args = {'dev': self.local_int,
                      'srcport': (cfg.CONF.VXLAN.udp_srcport_min,
                                  cfg.CONF.VXLAN.udp_srcport_max),
                      'dstport': cfg.CONF.VXLAN.udp_dstport,
                      'ttl': cfg.CONF.VXLAN.ttl}
              if cfg.CONF.VXLAN.tos:
                  args['tos'] = cfg.CONF.VXLAN.tos
                  if cfg.CONF.AGENT.dscp or cfg.CONF.AGENT.dscp_inherit:
                      LOG.warning('The deprecated tos option in group VXLAN '
                                  'is set and takes precedence over dscp and '
                                  'dscp_inherit in group AGENT.')
              elif cfg.CONF.AGENT.dscp_inherit:
                  args['tos'] = 'inherit'
              elif cfg.CONF.AGENT.dscp:
                  args['tos'] = int(cfg.CONF.AGENT.dscp) << 2
  
              if self.vxlan_mode == lconst.VXLAN_MCAST:
                  args['group'] = self.get_vxlan_group(segmentation_id)
              if cfg.CONF.VXLAN.l2_population:
                  args['proxy'] = cfg.CONF.VXLAN.arp_responder
  
              try:
                  int_vxlan = self.ip.add_vxlan(interface, segmentation_id,
                                                **args)
              except RuntimeError:
                  with excutils.save_and_reraise_exception() as ctxt:
                      # perform this check after an attempt rather than before
                      # to avoid excessive lookups and a possible race condition.
                      if ip_lib.vxlan_in_use(segmentation_id):
                          ctxt.reraise = False
                          LOG.error("Unable to create VXLAN interface for "
                                    "VNI %s because it is in use by another "
                                    "interface.", segmentation_id)
                          return None
              if mtu:
                  try:
                      int_vxlan.link.set_mtu(mtu)
                  except ip_lib.InvalidArgument:
                      phys_dev_mtu = ip_lib.get_device_mtu(self.local_int)
                      LOG.error("Provided MTU value %(mtu)s for VNI "
                                "%(segmentation_id)s is too high according "
                                "to physical device %(dev)s MTU=%(phys_mtu)s.",
                                {'mtu': mtu,
                                 'segmentation_id': segmentation_id,
                                 'dev': self.local_int,
                                 'phys_mtu': phys_dev_mtu})
                      int_vxlan.link.delete()
                      return None
              int_vxlan.disable_ipv6()
              int_vxlan.link.set_up()
              LOG.debug("Done creating vxlan interface %s", interface)
          return interface
  
      def _update_interface_ip_details(self, destination, source, ips, gateway):
          dst_device = self.ip.device(destination)
          src_device = self.ip.device(source)
  
          # Append IP's to bridge if necessary
          if ips:
              for ip in ips:
                  # If bridge ip address already exists, then don't add
                  # otherwise will report error
                  to = utils.cidr_to_ip(ip['cidr'])
                  if not dst_device.addr.list(to=to):
                      dst_device.addr.add(cidr=ip['cidr'])
  
          if gateway:
              # Ensure that the gateway can be updated by changing the metric
              metric = 100
              ip_version = utils.get_ip_version(gateway['cidr'])
              if gateway['metric'] != ip_lib.IP_ROUTE_METRIC_DEFAULT[ip_version]:
                  metric = gateway['metric'] - 1
              dst_device.route.add_gateway(gateway=gateway['via'],
                                           metric=metric)
              src_device.route.delete_gateway(gateway=gateway['via'])
  
          # Remove IP's from interface
          if ips:
              for ip in ips:
                  src_device.addr.delete(cidr=ip['cidr'])
  
      def update_interface_ip_details(self, destination, source):
          # Returns True if there were IPs or a gateway moved
          updated = False
          for ip_version in (constants.IP_VERSION_4, constants.IP_VERSION_6):
              ips, gateway = self.get_interface_details(source, ip_version)
              if ips or gateway:
                  self._update_interface_ip_details(destination, source, ips,
                                                    gateway)
                  updated = True
  
          return updated
  
      def ensure_bridge(self, bridge_name, interface=None,
                        update_interface=True):
          """Create a bridge unless it already exists."""
          # ensure_device_is_ready instead of device_exists is used here
          # because there are cases where the bridge exists but it's not UP,
          # for example:
          # 1) A greenthread was executing this function and had not yet executed
          # "ip link set bridge_name up" before eventlet switched to this
          # thread running the same function
          # 2) The Nova VIF driver was running concurrently and had just created
          #    the bridge, but had not yet put it UP
          if not ip_lib.ensure_device_is_ready(bridge_name):
              LOG.debug("Starting bridge %(bridge_name)s for subinterface "
                        "%(interface)s",
                        {'bridge_name': bridge_name, 'interface': interface})
              bridge_device = bridge_lib.BridgeDevice.addbr(bridge_name)
              if bridge_device.setfd(0):
                  return
              if bridge_device.disable_stp():
                  return
              if bridge_device.link.set_up():
                  return
              LOG.debug("Done starting bridge %(bridge_name)s for "
                        "subinterface %(interface)s",
                        {'bridge_name': bridge_name, 'interface': interface})
          else:
              bridge_device = bridge_lib.BridgeDevice(bridge_name)
  
          if not interface:
              return bridge_name
  
          # Update IP info if necessary
          if update_interface:
              self.update_interface_ip_details(bridge_name, interface)
  
          # Check if the interface is part of the bridge
          if not bridge_device.owns_interface(interface):
              try:
                  # Check if the interface is not enslaved in another bridge
                  bridge = bridge_lib.BridgeDevice.get_interface_bridge(
                      interface)
                  if bridge:
                      bridge.delif(interface)
  
                  bridge_device.addif(interface)
              except Exception as e:
                  LOG.error("Unable to add %(interface)s to %(bridge_name)s"
                            "! Exception: %(e)s",
                            {'interface': interface, 'bridge_name': bridge_name,
                             'e': e})
                  return
          return bridge_name
  
      def ensure_physical_in_bridge(self, network_id,
                                    network_type,
                                    physical_network,
                                    segmentation_id,
                                    mtu):
          if network_type == constants.TYPE_VXLAN:
              if self.vxlan_mode == lconst.VXLAN_NONE:
                  LOG.error("Unable to add vxlan interface for network %s",
                            network_id)
                  return
              return self.ensure_vxlan_bridge(network_id, segmentation_id, mtu)
  
          # NOTE(nick-ma-z): Obtain mappings of physical bridge and interfaces
          physical_bridge = self.bridge_mappings.get(physical_network)
          physical_interface = self.interface_mappings.get(physical_network)
          if not physical_bridge and not physical_interface:
              LOG.error("No bridge or interface mappings"
                        " for physical network %s",
                        physical_network)
              return
          if network_type == constants.TYPE_FLAT:
              return self.ensure_flat_bridge(network_id, physical_bridge,
                                             physical_interface)
          elif network_type == constants.TYPE_VLAN:
              return self.ensure_vlan_bridge(network_id, physical_bridge,
                                             physical_interface,
                                             segmentation_id)
          else:
              LOG.error("Unknown network_type %(network_type)s for network "
                        "%(network_id)s.", {network_type: network_type,
                                            network_id: network_id})
  
      def add_tap_interface(self, network_id, network_type, physical_network,
                            segmentation_id, tap_device_name, device_owner, mtu):
          """Add tap interface and handle interface missing exceptions."""
          try:
              return self._add_tap_interface(network_id, network_type,
                                             physical_network, segmentation_id,
                                             tap_device_name, device_owner, mtu)
          except Exception:
              with excutils.save_and_reraise_exception() as ctx:
                  if not ip_lib.device_exists(tap_device_name):
                      # the exception was likely a side effect of the tap device
                      # being removed during handling so we just return false
                      # like we would if it didn't exist to begin with.
                      ctx.reraise = False
                      return False
  
      def _add_tap_interface(self, network_id,
                             network_type, physical_network, segmentation_id,
                             tap_device_name, device_owner, mtu):
          """Add tap interface.
  
          If a VIF has been plugged into a network, this function will
          add the corresponding tap device to the relevant bridge.
          """
          if not ip_lib.device_exists(tap_device_name):
              LOG.debug("Tap device: %s does not exist on "
                        "this host, skipped", tap_device_name)
              return False
  
          bridge_name = self.bridge_mappings.get(physical_network)
          if not bridge_name:
              bridge_name = self.get_bridge_name(network_id)
  
          if network_type == constants.TYPE_LOCAL:
              self.ensure_local_bridge(network_id, bridge_name)
          elif not self.ensure_physical_in_bridge(network_id,
                                                  network_type,
                                                  physical_network,
                                                  segmentation_id,
                                                  mtu):
              return False
          if mtu:  # <-None with device_details from older neutron servers.
              # we ensure the MTU here because libvirt does not set the
              # MTU of a bridge it creates and the tap device it creates will
              # inherit from the bridge its plugged into, which will be 1500
              # at the time. See bug/1684326 for details.
              self._set_tap_mtu(tap_device_name, mtu)
          # Avoid messing with plugging devices into a bridge that the agent
          # does not own
          if not device_owner.startswith(constants.DEVICE_OWNER_COMPUTE_PREFIX):
              # Check if device needs to be added to bridge
              if not bridge_lib.BridgeDevice.get_interface_bridge(
                      tap_device_name):
                  data = {'tap_device_name': tap_device_name,
                          'bridge_name': bridge_name}
                  LOG.debug("Adding device %(tap_device_name)s to bridge "
                            "%(bridge_name)s", data)
                  if bridge_lib.BridgeDevice(bridge_name).addif(tap_device_name):
                      return False
          else:
              data = {'tap_device_name': tap_device_name,
                      'device_owner': device_owner,
                      'bridge_name': bridge_name}
              LOG.debug("Skip adding device %(tap_device_name)s to "
                        "%(bridge_name)s. It is owned by %(device_owner)s and "
                        "thus added elsewhere.", data)
          return True
  
      @staticmethod
      def _set_tap_mtu(tap_device_name, mtu):
          ip_lib.IPDevice(tap_device_name).link.set_mtu(mtu)
  
      def plug_interface(self, network_id, network_segment, tap_name,
                         device_owner):
          return self.add_tap_interface(network_id, network_segment.network_type,
                                        network_segment.physical_network,
                                        network_segment.segmentation_id,
                                        tap_name, device_owner,
                                        network_segment.mtu)
  
      def delete_bridge(self, bridge_name):
          bridge_device = bridge_lib.BridgeDevice(bridge_name)
          if bridge_device.exists():
              physical_interfaces = set(self.interface_mappings.values())
              interfaces_on_bridge = bridge_device.get_interfaces()
              for interface in interfaces_on_bridge:
                  self.remove_interface(bridge_name, interface)
  
                  if interface.startswith(VXLAN_INTERFACE_PREFIX):
                      self.delete_interface(interface)
                  else:
                      # Match the vlan/flat interface in the bridge.
                      # If the bridge has an IP, it mean that this IP was moved
                      # from the current interface, which also mean that this
                      # interface was not created by the agent.
                      updated = self.update_interface_ip_details(interface,
                                                                 bridge_name)
                      if not updated and interface not in physical_interfaces:
                          self.delete_interface(interface)
  
              try:
                  LOG.debug("Deleting bridge %s", bridge_name)
                  if bridge_device.link.set_down():
                      return
                  if bridge_device.delbr():
                      return
                  LOG.debug("Done deleting bridge %s", bridge_name)
              except RuntimeError:
                  with excutils.save_and_reraise_exception() as ctxt:
                      if not bridge_device.exists():
                          # the exception was likely a side effect of the bridge
                          # being removed by nova during handling,
                          # so we just return
                          ctxt.reraise = False
                          LOG.debug("Cannot delete bridge %s; it does not exist",
                                    bridge_name)
                          return
          else:
              LOG.debug("Cannot delete bridge %s; it does not exist",
                        bridge_name)
  
      @staticmethod
      def remove_interface(bridge_name, interface_name):
          bridge_device = bridge_lib.BridgeDevice(bridge_name)
          if bridge_device.exists():
              if not bridge_device.owns_interface(interface_name):
                  return True
              LOG.debug("Removing device %(interface_name)s from bridge "
                        "%(bridge_name)s",
                        {'interface_name': interface_name,
                         'bridge_name': bridge_name})
              try:
                  bridge_device.delif(interface_name)
                  LOG.debug("Done removing device %(interface_name)s from "
                            "bridge %(bridge_name)s",
                            {'interface_name': interface_name,
                             'bridge_name': bridge_name})
                  return True
              except RuntimeError:
                  with excutils.save_and_reraise_exception() as ctxt:
                      if not bridge_device.owns_interface(interface_name):
                          # the exception was likely a side effect of the tap
                          # being deleted by some other agent during handling
                          ctxt.reraise = False
                          LOG.debug("Cannot remove %(interface_name)s from "
                                    "%(bridge_name)s. It is not on the bridge.",
                                    {'interface_name': interface_name,
                                     'bridge_name': bridge_name})
                          return False
          else:
              LOG.debug("Cannot remove device %(interface_name)s bridge "
                        "%(bridge_name)s does not exist",
                        {'interface_name': interface_name,
                         'bridge_name': bridge_name})
              return False
  
      def delete_interface(self, interface):
          device = self.ip.device(interface)
          if device.exists():
              LOG.debug("Deleting interface %s",
                        interface)
              device.link.set_down()
              device.link.delete()
              LOG.debug("Done deleting interface %s", interface)
  
      def get_devices_modified_timestamps(self, devices):
          # NOTE(kevinbenton): we aren't returning real timestamps here. We
          # are returning interface indexes instead which change when the
          # interface is removed/re-added. This works for the direct
          # comparison the common agent loop performs with these.
          # See bug/1622833 for details.
          return {d: bridge_lib.get_interface_ifindex(d) for d in devices}
  
      @staticmethod
      def get_all_devices():
          devices = set()
          for device in bridge_lib.get_bridge_names():
              if device.startswith(constants.TAP_DEVICE_PREFIX):
                  devices.add(device)
          return devices
  
      def vxlan_ucast_supported(self):
          if not cfg.CONF.VXLAN.l2_population:
              return False
          if not ip_lib.iproute_arg_supported(
                  ['bridge', 'fdb'], 'append'):
              LOG.warning('Option "%(option)s" must be supported by command '
                          '"%(command)s" to enable %(mode)s mode',
                          {'option': 'append',
                           'command': 'bridge fdb',
                           'mode': 'VXLAN UCAST'})
              return False
  
          test_iface = None
          for seg_id in moves.range(1, constants.MAX_VXLAN_VNI + 1):
              if (ip_lib.device_exists(self.get_vxlan_device_name(seg_id)) or
                      ip_lib.vxlan_in_use(seg_id)):
                  continue
              test_iface = self.ensure_vxlan(seg_id)
              break
          else:
              LOG.error('No valid Segmentation ID to perform UCAST test.')
              return False
  
          try:
              bridge_lib.FdbInterface.append(constants.FLOODING_ENTRY[0],
                                             test_iface, '1.1.1.1',
                                             log_fail_as_error=False)
              return True
          except RuntimeError:
              return False
          finally:
              self.delete_interface(test_iface)
  
      @staticmethod
      def vxlan_mcast_supported():
          if not cfg.CONF.VXLAN.vxlan_group:
              LOG.warning('VXLAN muticast group(s) must be provided in '
                          'vxlan_group option to enable VXLAN MCAST mode')
              return False
          if not ip_lib.iproute_arg_supported(
                  ['ip', 'link', 'add', 'type', 'vxlan'],
                  'proxy'):
              LOG.warning('Option "%(option)s" must be supported by command '
                          '"%(command)s" to enable %(mode)s mode',
                          {'option': 'proxy',
                           'command': 'ip link add type vxlan',
                           'mode': 'VXLAN MCAST'})
  
              return False
          return True
  
      def check_vxlan_support(self):
          self.vxlan_mode = lconst.VXLAN_NONE
  
          if self.vxlan_ucast_supported():
              self.vxlan_mode = lconst.VXLAN_UCAST
          elif self.vxlan_mcast_supported():
              self.vxlan_mode = lconst.VXLAN_MCAST
          else:
              raise exceptions.VxlanNetworkUnsupported()
          LOG.debug('Using %s VXLAN mode', self.vxlan_mode)
  
      @staticmethod
      def fdb_ip_entry_exists(mac, ip, interface):
          ip_version = utils.get_ip_version(ip)
          entry = ip_lib.dump_neigh_entries(ip_version, interface, dst=ip,
                                            lladdr=mac)
          return entry != []
  
      @staticmethod
      def fdb_bridge_entry_exists(mac, interface, agent_ip=None):
          entries = bridge_lib.FdbInterface.show(interface)
          if not agent_ip:
              return mac in entries
  
          return (agent_ip in entries and mac in entries)
  
      @staticmethod
      def add_fdb_ip_entry(mac, ip, interface):
          if cfg.CONF.VXLAN.arp_responder:
              ip_lib.add_neigh_entry(ip, mac, interface)
  
      @staticmethod
      def remove_fdb_ip_entry(mac, ip, interface):
          if cfg.CONF.VXLAN.arp_responder:
              ip_lib.delete_neigh_entry(ip, mac, interface)
  
      def add_fdb_entries(self, agent_ip, ports, interface):
          for mac, ip in ports:
              if mac != constants.FLOODING_ENTRY[0]:
                  self.add_fdb_ip_entry(mac, ip, interface)
                  bridge_lib.FdbInterface.replace(mac, interface, agent_ip,
                                                  check_exit_code=False)
              elif self.vxlan_mode == lconst.VXLAN_UCAST:
                  if self.fdb_bridge_entry_exists(mac, interface):
                      bridge_lib.FdbInterface.append(mac, interface, agent_ip,
                                                     check_exit_code=False)
                  else:
                      bridge_lib.FdbInterface.add(mac, interface, agent_ip,
                                                  check_exit_code=False)
  
      def remove_fdb_entries(self, agent_ip, ports, interface):
          for mac, ip in ports:
              if mac != constants.FLOODING_ENTRY[0]:
                  self.remove_fdb_ip_entry(mac, ip, interface)
                  bridge_lib.FdbInterface.delete(mac, interface, agent_ip,
                                                 check_exit_code=False)
              elif self.vxlan_mode == lconst.VXLAN_UCAST:
                  bridge_lib.FdbInterface.delete(mac, interface, agent_ip,
                                                 check_exit_code=False)
  
      def get_agent_id(self):
          if self.bridge_mappings:
              mac = ip_lib.get_device_mac(
                  list(self.bridge_mappings.values())[0])
          else:
              devices = self.ip.get_devices(True)
              for device in devices:
                  mac = ip_lib.get_device_mac(device.name)
                  if mac:
                      break
              else:
                  LOG.error("Unable to obtain MAC address for unique ID. "
                            "Agent terminated!")
                  sys.exit(1)
          return 'lb%s' % mac.replace(":", "")
  
      def get_agent_configurations(self):
          configurations = {'bridge_mappings': self.bridge_mappings,
                            'interface_mappings': self.interface_mappings
                            }
          if self.vxlan_mode != lconst.VXLAN_NONE:
              configurations['tunneling_ip'] = self.local_ip
              configurations['tunnel_types'] = [constants.TYPE_VXLAN]
              configurations['l2_population'] = cfg.CONF.VXLAN.l2_population
          return configurations
  
      def get_rpc_callbacks(self, context, agent, sg_agent):
          return LinuxBridgeRpcCallbacks(context, agent, sg_agent)
  
      def get_agent_api(self, **kwargs):
          if self.agent_api:
              return self.agent_api
          sg_agent = kwargs.get("sg_agent")
          iptables_manager = self._get_iptables_manager(sg_agent)
          self.agent_api = agent_extension_api.LinuxbridgeAgentExtensionAPI(
              iptables_manager)
          return self.agent_api
  
      @staticmethod
      def _get_iptables_manager(sg_agent):
          if not sg_agent:
              return None
          if cfg.CONF.SECURITYGROUP.firewall_driver in IPTABLES_DRIVERS:
              return sg_agent.firewall.iptables
  
      def get_rpc_consumers(self):
          consumers = [[topics.PORT, topics.UPDATE],
                       [topics.NETWORK, topics.DELETE],
                       [topics.NETWORK, topics.UPDATE],
                       [topics.SECURITY_GROUP, topics.UPDATE],
                       [topics.PORT_BINDING, topics.DEACTIVATE],
                       [topics.PORT_BINDING, topics.ACTIVATE]]
          if cfg.CONF.VXLAN.l2_population:
              consumers.append([topics.L2POPULATION, topics.UPDATE])
          return consumers
  
      def ensure_port_admin_state(self, tap_name, admin_state_up):
          LOG.debug("Setting admin_state_up to %s for device %s",
                    admin_state_up, tap_name)
          if admin_state_up:
              ip_lib.IPDevice(tap_name).link.set_up()
          else:
              ip_lib.IPDevice(tap_name).link.set_down()
  
      def setup_arp_spoofing_protection(self, device, device_details):
          arp_protect.setup_arp_spoofing_protection(device, device_details)
  
      def delete_arp_spoofing_protection(self, devices):
          arp_protect.delete_arp_spoofing_protection(devices)
  
      def delete_unreferenced_arp_protection(self, current_devices):
          arp_protect.delete_unreferenced_arp_protection(current_devices)
  
      def get_extension_driver_type(self):
          return lconst.EXTENSION_DRIVER_TYPE
  
  
  class LinuxBridgeRpcCallbacks(sg_rpc.SecurityGroupAgentRpcCallbackMixin,
                                l2pop_rpc.L2populationRpcCallBackMixin,
                                amb.CommonAgentManagerRpcCallBackBase):
  
      # Set RPC API version to 1.0 by default.
      # history
      #   1.1 Support Security Group RPC
      #   1.3 Added param devices_to_update to security_groups_provider_updated
      #   1.4 Added support for network_update
      #   1.5 Added binding_activate and binding_deactivate
      target = oslo_messaging.Target(version='1.5')
  
      def network_delete(self, context, **kwargs):
          LOG.debug("network_delete received")
          network_id = kwargs.get('network_id')
  
          # NOTE(nick-ma-z): Don't remove pre-existing user-defined bridges
          if network_id in self.network_map:
              phynet = self.network_map[network_id].physical_network
              if phynet and phynet in self.agent.mgr.bridge_mappings:
                  LOG.info("Physical network %s is defined in "
                           "bridge_mappings and cannot be deleted.",
                           network_id)
                  return
  
          bridge_name = self.agent.mgr.get_bridge_name(network_id)
          LOG.debug("Delete %s", bridge_name)
          self.agent.mgr.delete_bridge(bridge_name)
          self.network_map.pop(network_id, None)
  
      def port_update(self, context, **kwargs):
          port_id = kwargs['port']['id']
          device_name = self.agent.mgr.get_tap_device_name(port_id)
          # Put the device name in the updated_devices set.
          # Do not store port details, as if they're used for processing
          # notifications there is no guarantee the notifications are
          # processed in the same order as the relevant API requests.
          self.updated_devices.add(device_name)
          LOG.debug("port_update RPC received for port: %s", port_id)
  
      def binding_deactivate(self, context, **kwargs):
          if kwargs.get('host') != cfg.CONF.host:
              return
          interface_name = self.agent.mgr.get_tap_device_name(
              kwargs.get('port_id'))
          bridge_name = self.agent.mgr.get_bridge_name(kwargs.get('network_id'))
          LOG.debug("Removing device %(interface_name)s from bridge "
                    "%(bridge_name)s due to binding being de-activated",
                    {'interface_name': interface_name,
                     'bridge_name': bridge_name})
          self.agent.mgr.remove_interface(bridge_name, interface_name)
  
      def binding_activate(self, context, **kwargs):
          if kwargs.get('host') != cfg.CONF.host:
              return
          # Since the common agent loop treats added and updated the same way,
          # just add activated ports to the updated devices list. This way,
          # adding binding activation is less disruptive to the existing code
          port_id = kwargs.get('port_id')
          device_name = self.agent.mgr.get_tap_device_name(port_id)
          self.updated_devices.add(device_name)
          LOG.debug("Binding activation received for port: %s", port_id)
  
      def network_update(self, context, **kwargs):
          network_id = kwargs['network']['id']
          LOG.debug("network_update message processed for network "
                    "%(network_id)s, with ports: %(ports)s",
                    {'network_id': network_id,
                     'ports': self.agent.network_ports[network_id]})
          for port_data in self.agent.network_ports[network_id]:
              self.updated_devices.add(port_data['device'])
  
      def fdb_add(self, context, fdb_entries):
          LOG.debug("fdb_add received")
          for network_id, values in fdb_entries.items():
              segment = self.network_map.get(network_id)
              if not segment:
                  return
  
              if segment.network_type != constants.TYPE_VXLAN:
                  return
  
              interface = self.agent.mgr.get_vxlan_device_name(
                  segment.segmentation_id)
  
              agent_ports = values.get('ports')
              for agent_ip, ports in agent_ports.items():
                  if agent_ip == self.agent.mgr.local_ip:
                      continue
  
                  self.agent.mgr.add_fdb_entries(agent_ip,
                                                 ports,
                                                 interface)
  
      def fdb_remove(self, context, fdb_entries):
          LOG.debug("fdb_remove received")
          for network_id, values in fdb_entries.items():
              segment = self.network_map.get(network_id)
              if not segment:
                  return
  
              if segment.network_type != constants.TYPE_VXLAN:
                  return
  
              interface = self.agent.mgr.get_vxlan_device_name(
                  segment.segmentation_id)
  
              agent_ports = values.get('ports')
              for agent_ip, ports in agent_ports.items():
                  if agent_ip == self.agent.mgr.local_ip:
                      continue
  
                  self.agent.mgr.remove_fdb_entries(agent_ip,
                                                    ports,
                                                    interface)
  
      def _fdb_chg_ip(self, context, fdb_entries):
          LOG.debug("update chg_ip received")
          for network_id, agent_ports in fdb_entries.items():
              segment = self.network_map.get(network_id)
              if not segment:
                  return
  
              if segment.network_type != constants.TYPE_VXLAN:
                  return
  
              interface = self.agent.mgr.get_vxlan_device_name(
                  segment.segmentation_id)
  
              for agent_ip, state in agent_ports.items():
                  if agent_ip == self.agent.mgr.local_ip:
                      continue
  
                  after = state.get('after', [])
                  for mac, ip in after:
                      self.agent.mgr.add_fdb_ip_entry(mac, ip, interface)
  
                  before = state.get('before', [])
                  for mac, ip in before:
                      self.agent.mgr.remove_fdb_ip_entry(mac, ip, interface)
  
      def fdb_update(self, context, fdb_entries):
          LOG.debug("fdb_update received")
          for action, values in fdb_entries.items():
              method = '_fdb_' + action
              if not hasattr(self, method):
                  raise NotImplementedError()
  
              getattr(self, method)(context, values)
  
  
  def main():
      common_config.init(sys.argv[1:])
  
      common_config.setup_logging()
      agent_config.setup_privsep()
      service_conf.register_service_opts(service_conf.RPC_EXTRA_OPTS, cfg.CONF)
  
      try:
          interface_mappings = helpers.parse_mappings(
              cfg.CONF.LINUX_BRIDGE.physical_interface_mappings)
      except ValueError as e:
          LOG.error("Parsing physical_interface_mappings failed: %s. "
                    "Agent terminated!", e)
          sys.exit(1)
      LOG.info("Interface mappings: %s", interface_mappings)
  
      try:
          bridge_mappings = helpers.parse_mappings(
              cfg.CONF.LINUX_BRIDGE.bridge_mappings)
      except ValueError as e:
          LOG.error("Parsing bridge_mappings failed: %s. "
                    "Agent terminated!", e)
          sys.exit(1)
      LOG.info("Bridge mappings: %s", bridge_mappings)
  
      manager = LinuxBridgeManager(bridge_mappings, interface_mappings)
      linuxbridge_capabilities.register()
  
      polling_interval = cfg.CONF.AGENT.polling_interval
      quitting_rpc_timeout = cfg.CONF.AGENT.quitting_rpc_timeout
      agent = ca.CommonAgentLoop(manager, polling_interval, quitting_rpc_timeout,
                                 constants.AGENT_TYPE_LINUXBRIDGE,
                                 LB_AGENT_BINARY)
      setup_profiler.setup("neutron-linuxbridge-agent", cfg.CONF.host)
      LOG.info("Agent initialized successfully, now running... ")
      launcher = service.launch(cfg.CONF, agent, restart_method='mutate')
      launcher.wait()
  