text: #!/usr/bin/env python
  # Copyright 2011 VMware, 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.
  
  import hashlib
  import signal
  import sys
  import time
  
  import eventlet
  eventlet.monkey_patch()
  
  import netaddr
  from neutron.plugins.openvswitch.agent import ovs_dvr_neutron_agent
  from oslo.config import cfg
  from six import moves
  
  from neutron.agent import l2population_rpc
  from neutron.agent.linux import ip_lib
  from neutron.agent.linux import ovs_lib
  from neutron.agent.linux import polling
  from neutron.agent.linux import utils
  from neutron.agent import rpc as agent_rpc
  from neutron.agent import securitygroups_rpc as sg_rpc
  from neutron.api.rpc.handlers import dvr_rpc
  from neutron.common import config as common_config
  from neutron.common import constants as q_const
  from neutron.common import exceptions
  from neutron.common import rpc as n_rpc
  from neutron.common import topics
  from neutron.common import utils as q_utils
  from neutron import context
  from neutron.openstack.common import log as logging
  from neutron.openstack.common import loopingcall
  from neutron.plugins.common import constants as p_const
  from neutron.plugins.openvswitch.common import config  # noqa
  from neutron.plugins.openvswitch.common import constants
  
  
  LOG = logging.getLogger(__name__)
  
  # A placeholder for dead vlans.
  DEAD_VLAN_TAG = str(q_const.MAX_VLAN_TAG + 1)
  
  
  class DeviceListRetrievalError(exceptions.NeutronException):
      message = _("Unable to retrieve port details for devices: %(devices)s "
                  "because of error: %(error)s")
  
  
  # A class to represent a VIF (i.e., a port that has 'iface-id' and 'vif-mac'
  # attributes set).
  class LocalVLANMapping:
      def __init__(self, vlan, network_type, physical_network, segmentation_id,
                   vif_ports=None):
          if vif_ports is None:
              vif_ports = {}
          self.vlan = vlan
          self.network_type = network_type
          self.physical_network = physical_network
          self.segmentation_id = segmentation_id
          self.vif_ports = vif_ports
          # set of tunnel ports on which packets should be flooded
          self.tun_ofports = set()
  
      def __str__(self):
          return ("lv-id = %s type = %s phys-net = %s phys-id = %s" %
                  (self.vlan, self.network_type, self.physical_network,
                   self.segmentation_id))
  
  
  class OVSPluginApi(agent_rpc.PluginApi,
                     dvr_rpc.DVRServerRpcApiMixin,
                     sg_rpc.SecurityGroupServerRpcApiMixin):
      pass
  
  
  class OVSSecurityGroupAgent(sg_rpc.SecurityGroupAgentRpcMixin):
      def __init__(self, context, plugin_rpc, root_helper):
          self.context = context
          self.plugin_rpc = plugin_rpc
          self.root_helper = root_helper
          self.init_firewall(defer_refresh_firewall=True)
  
  
  class OVSNeutronAgent(n_rpc.RpcCallback,
                        sg_rpc.SecurityGroupAgentRpcCallbackMixin,
                        l2population_rpc.L2populationRpcCallBackTunnelMixin,
                        dvr_rpc.DVRAgentRpcCallbackMixin):
      '''Implements OVS-based tunneling, VLANs and flat networks.
  
      Two local bridges are created: an integration bridge (defaults to
      'br-int') and a tunneling bridge (defaults to 'br-tun'). An
      additional bridge is created for each physical network interface
      used for VLANs and/or flat networks.
  
      All VM VIFs are plugged into the integration bridge. VM VIFs on a
      given virtual network share a common "local" VLAN (i.e. not
      propagated externally). The VLAN id of this local VLAN is mapped
      to the physical networking details realizing that virtual network.
  
      For virtual networks realized as GRE tunnels, a Logical Switch
      (LS) identifier is used to differentiate tenant traffic on
      inter-HV tunnels. A mesh of tunnels is created to other
      Hypervisors in the cloud. These tunnels originate and terminate on
      the tunneling bridge of each hypervisor. Port patching is done to
      connect local VLANs on the integration bridge to inter-hypervisor
      tunnels on the tunnel bridge.
  
      For each virtual network realized as a VLAN or flat network, a
      veth or a pair of patch ports is used to connect the local VLAN on
      the integration bridge with the physical network bridge, with flow
      rules adding, modifying, or stripping VLAN tags as necessary.
      '''
  
      # history
      #   1.0 Initial version
      #   1.1 Support Security Group RPC
      #   1.2 Support DVR (Distributed Virtual Router) RPC
      RPC_API_VERSION = '1.2'
  
      def __init__(self, integ_br, tun_br, local_ip,
                   bridge_mappings, root_helper,
                   polling_interval, tunnel_types=None,
                   veth_mtu=None, l2_population=False,
                   enable_distributed_routing=False,
                   minimize_polling=False,
                   ovsdb_monitor_respawn_interval=(
                       constants.DEFAULT_OVSDBMON_RESPAWN),
                   arp_responder=False,
                   use_veth_interconnection=False):
          '''Constructor.
  
          :param integ_br: name of the integration bridge.
          :param tun_br: name of the tunnel bridge.
          :param local_ip: local IP address of this hypervisor.
          :param bridge_mappings: mappings from physical network name to bridge.
          :param root_helper: utility to use when running shell cmds.
          :param polling_interval: interval (secs) to poll DB.
          :param tunnel_types: A list of tunnel types to enable support for in
                 the agent. If set, will automatically set enable_tunneling to
                 True.
          :param veth_mtu: MTU size for veth interfaces.
          :param l2_population: Optional, whether L2 population is turned on
          :param minimize_polling: Optional, whether to minimize polling by
                 monitoring ovsdb for interface changes.
          :param ovsdb_monitor_respawn_interval: Optional, when using polling
                 minimization, the number of seconds to wait before respawning
                 the ovsdb monitor.
          :param arp_responder: Optional, enable local ARP responder if it is
                 supported.
          :param use_veth_interconnection: use veths instead of patch ports to
                 interconnect the integration bridge to physical bridges.
          '''
          super(OVSNeutronAgent, self).__init__()
          self.use_veth_interconnection = use_veth_interconnection
          self.veth_mtu = veth_mtu
          self.root_helper = root_helper
          self.available_local_vlans = set(moves.xrange(q_const.MIN_VLAN_TAG,
                                                        q_const.MAX_VLAN_TAG))
          self.tunnel_types = tunnel_types or []
          self.l2_pop = l2_population
          # TODO(ethuleau): Change ARP responder so it's not dependent on the
          #                 ML2 l2 population mechanism driver.
          self.enable_distributed_routing = enable_distributed_routing
          self.arp_responder_enabled = arp_responder and self.l2_pop
          self.agent_state = {
              'binary': 'neutron-openvswitch-agent',
              'host': cfg.CONF.host,
              'topic': q_const.L2_AGENT_TOPIC,
              'configurations': {'bridge_mappings': bridge_mappings,
                                 'tunnel_types': self.tunnel_types,
                                 'tunneling_ip': local_ip,
                                 'l2_population': self.l2_pop,
                                 'arp_responder_enabled':
                                 self.arp_responder_enabled,
                                 'enable_distributed_routing':
                                 self.enable_distributed_routing},
              'agent_type': q_const.AGENT_TYPE_OVS,
              'start_flag': True}
  
          # Keep track of int_br's device count for use by _report_state()
          self.int_br_device_count = 0
  
          self.int_br = ovs_lib.OVSBridge(integ_br, self.root_helper)
          self.setup_integration_br()
          # Stores port update notifications for processing in main rpc loop
          self.updated_ports = set()
          self.setup_rpc()
          self.bridge_mappings = bridge_mappings
          self.setup_physical_bridges(self.bridge_mappings)
          self.local_vlan_map = {}
          self.tun_br_ofports = {p_const.TYPE_GRE: {},
                                 p_const.TYPE_VXLAN: {}}
  
          self.polling_interval = polling_interval
          self.minimize_polling = minimize_polling
          self.ovsdb_monitor_respawn_interval = ovsdb_monitor_respawn_interval
  
          if tunnel_types:
              self.enable_tunneling = True
          else:
              self.enable_tunneling = False
          self.local_ip = local_ip
          self.tunnel_count = 0
          self.vxlan_udp_port = cfg.CONF.AGENT.vxlan_udp_port
          self.dont_fragment = cfg.CONF.AGENT.dont_fragment
          self.tun_br = None
          self.patch_int_ofport = constants.OFPORT_INVALID
          self.patch_tun_ofport = constants.OFPORT_INVALID
          if self.enable_tunneling:
              # The patch_int_ofport and patch_tun_ofport are updated
              # here inside the call to setup_tunnel_br
              self.setup_tunnel_br(tun_br)
  
          self.dvr_agent = ovs_dvr_neutron_agent.OVSDVRNeutronAgent(
              self.context,
              self.plugin_rpc,
              self.int_br,
              self.tun_br,
              self.patch_int_ofport,
              self.patch_tun_ofport,
              cfg.CONF.host,
              self.enable_tunneling,
              self.enable_distributed_routing)
  
          self.dvr_agent.setup_dvr_flows_on_integ_tun_br()
  
          # Collect additional bridges to monitor
          self.ancillary_brs = self.setup_ancillary_bridges(integ_br, tun_br)
  
          # Security group agent support
          self.sg_agent = OVSSecurityGroupAgent(self.context,
                                                self.plugin_rpc,
                                                root_helper)
          # Initialize iteration counter
          self.iter_num = 0
          self.run_daemon_loop = True
  
      def _report_state(self):
          # How many devices are likely used by a VM
          self.agent_state.get('configurations')['devices'] = (
              self.int_br_device_count)
          try:
              self.state_rpc.report_state(self.context,
                                          self.agent_state)
              self.agent_state.pop('start_flag', None)
          except Exception:
              LOG.exception(_("Failed reporting state!"))
  
      def setup_rpc(self):
          self.agent_id = 'ovs-agent-%s' % cfg.CONF.host
          self.topic = topics.AGENT
          self.plugin_rpc = OVSPluginApi(topics.PLUGIN)
          self.state_rpc = agent_rpc.PluginReportStateAPI(topics.PLUGIN)
  
          # RPC network init
          self.context = context.get_admin_context_without_session()
          # Handle updates from service
          self.endpoints = [self]
          # Define the listening consumers for the agent
          consumers = [[topics.PORT, topics.UPDATE],
                       [topics.NETWORK, topics.DELETE],
                       [constants.TUNNEL, topics.UPDATE],
                       [topics.SECURITY_GROUP, topics.UPDATE],
                       [topics.DVR, topics.UPDATE]]
          if self.l2_pop:
              consumers.append([topics.L2POPULATION,
                                topics.UPDATE, cfg.CONF.host])
          self.connection = agent_rpc.create_consumers(self.endpoints,
                                                       self.topic,
                                                       consumers)
          report_interval = cfg.CONF.AGENT.report_interval
          if report_interval:
              heartbeat = loopingcall.FixedIntervalLoopingCall(
                  self._report_state)
              heartbeat.start(interval=report_interval)
  
      def get_net_uuid(self, vif_id):
          for network_id, vlan_mapping in self.local_vlan_map.iteritems():
              if vif_id in vlan_mapping.vif_ports:
                  return network_id
  
      def network_delete(self, context, **kwargs):
          LOG.debug(_("network_delete received"))
          network_id = kwargs.get('network_id')
          LOG.debug(_("Delete %s"), network_id)
          # The network may not be defined on this agent
          lvm = self.local_vlan_map.get(network_id)
          if lvm:
              self.reclaim_local_vlan(network_id)
          else:
              LOG.debug(_("Network %s not used on agent."), network_id)
  
      def port_update(self, context, **kwargs):
          port = kwargs.get('port')
          # Put the port identifier in the updated_ports set.
          # Even if full port details might be provided to this call,
          # they are not used since there is no guarantee the notifications
          # are processed in the same order as the relevant API requests
          self.updated_ports.add(port['id'])
          LOG.debug(_("port_update message processed for port %s"), port['id'])
  
      def tunnel_update(self, context, **kwargs):
          LOG.debug(_("tunnel_update received"))
          if not self.enable_tunneling:
              return
          tunnel_ip = kwargs.get('tunnel_ip')
          tunnel_id = kwargs.get('tunnel_id', self.get_ip_in_hex(tunnel_ip))
          if not tunnel_id:
              return
          tunnel_type = kwargs.get('tunnel_type')
          if not tunnel_type:
              LOG.error(_("No tunnel_type specified, cannot create tunnels"))
              return
          if tunnel_type not in self.tunnel_types:
              LOG.error(_("tunnel_type %s not supported by agent"), tunnel_type)
              return
          if tunnel_ip == self.local_ip:
              return
          tun_name = '%s-%s' % (tunnel_type, tunnel_id)
          if not self.l2_pop:
              self._setup_tunnel_port(tun_name, tunnel_ip, tunnel_type)
  
      def fdb_add(self, context, fdb_entries):
          LOG.debug("fdb_add received")
          for lvm, agent_ports in self.get_agent_ports(fdb_entries,
                                                       self.local_vlan_map):
              agent_ports.pop(self.local_ip, None)
              if len(agent_ports):
                  if not self.enable_distributed_routing:
                      self.tun_br.defer_apply_on()
                  self.fdb_add_tun(context, lvm, agent_ports,
                                   self.tun_br_ofports)
                  if not self.enable_distributed_routing:
                      self.tun_br.defer_apply_off()
  
      def fdb_remove(self, context, fdb_entries):
          LOG.debug("fdb_remove received")
          for lvm, agent_ports in self.get_agent_ports(fdb_entries,
                                                       self.local_vlan_map):
              agent_ports.pop(self.local_ip, None)
              if len(agent_ports):
                  if not self.enable_distributed_routing:
                      self.tun_br.defer_apply_on()
                  self.fdb_remove_tun(context, lvm, agent_ports,
                                      self.tun_br_ofports)
                  if not self.enable_distributed_routing:
                      self.tun_br.defer_apply_off()
  
      def add_fdb_flow(self, port_info, remote_ip, lvm, ofport):
          if port_info == q_const.FLOODING_ENTRY:
              lvm.tun_ofports.add(ofport)
              ofports = ','.join(lvm.tun_ofports)
              self.tun_br.mod_flow(table=constants.FLOOD_TO_TUN,
                                   dl_vlan=lvm.vlan,
                                   actions="strip_vlan,set_tunnel:%s,"
                                   "output:%s" % (lvm.segmentation_id, ofports))
          else:
              self._set_arp_responder('add', lvm.vlan, port_info[0],
                                      port_info[1])
              if not self.dvr_agent.is_dvr_router_interface(port_info[1]):
                  self.tun_br.add_flow(table=constants.UCAST_TO_TUN,
                                       priority=2,
                                       dl_vlan=lvm.vlan,
                                       dl_dst=port_info[0],
                                       actions="strip_vlan,set_tunnel:%s,"
                                       "output:%s" %
                                       (lvm.segmentation_id, ofport))
  
      def del_fdb_flow(self, port_info, remote_ip, lvm, ofport):
          if port_info == q_const.FLOODING_ENTRY:
              lvm.tun_ofports.remove(ofport)
              if len(lvm.tun_ofports) > 0:
                  ofports = ','.join(lvm.tun_ofports)
                  self.tun_br.mod_flow(table=constants.FLOOD_TO_TUN,
                                       dl_vlan=lvm.vlan,
                                       actions="strip_vlan,"
                                       "set_tunnel:%s,output:%s" %
                                       (lvm.segmentation_id, ofports))
              else:
                  # This local vlan doesn't require any more tunnelling
                  self.tun_br.delete_flows(table=constants.FLOOD_TO_TUN,
                                           dl_vlan=lvm.vlan)
          else:
              self._set_arp_responder('remove', lvm.vlan, port_info[0],
                                      port_info[1])
              self.tun_br.delete_flows(table=constants.UCAST_TO_TUN,
                                       dl_vlan=lvm.vlan,
                                       dl_dst=port_info[0])
  
      def _fdb_chg_ip(self, context, fdb_entries):
          '''fdb update when an IP of a port is updated.
  
          The ML2 l2-pop mechanism driver send an fdb update rpc message when an
          IP of a port is updated.
  
          :param context: RPC context.
          :param fdb_entries: fdb dicts that contain all mac/IP informations per
                              agent and network.
                                 {'net1':
                                  {'agent_ip':
                                   {'before': [[mac, ip]],
                                    'after': [[mac, ip]]
                                   }
                                  }
                                  'net2':
                                  ...
                                 }
          '''
          LOG.debug(_("update chg_ip received"))
  
          # TODO(ethuleau): Use OVS defer apply flows for all rules will be an
          # interesting improvement here. But actually, OVS lib defer apply flows
          # methods doesn't ensure the add flows will be applied before delete.
          for network_id, agent_ports in fdb_entries.items():
              lvm = self.local_vlan_map.get(network_id)
              if not lvm:
                  continue
  
              for agent_ip, state in agent_ports.items():
                  if agent_ip == self.local_ip:
                      continue
  
                  after = state.get('after')
                  for mac, ip in after:
                      self._set_arp_responder('add', lvm.vlan, mac, ip)
  
                  before = state.get('before')
                  for mac, ip in before:
                      self._set_arp_responder('remove', lvm.vlan, mac, ip)
  
      def _set_arp_responder(self, action, lvid, mac_str, ip_str):
          '''Set the ARP respond entry.
  
          When the l2 population mechanism driver and OVS supports to edit ARP
          fields, a table (ARP_RESPONDER) to resolve ARP locally is added to the
          tunnel bridge.
  
          :param action: add or remove ARP entry.
          :param lvid: local VLAN map of network's ARP entry.
          :param mac_str: MAC string value.
          :param ip_str: IP string value.
          '''
          if not self.arp_responder_enabled:
              return
  
          mac = netaddr.EUI(mac_str, dialect=netaddr.mac_unix)
          ip = netaddr.IPAddress(ip_str)
  
          if action == 'add':
              actions = constants.ARP_RESPONDER_ACTIONS % {'mac': mac, 'ip': ip}
              self.tun_br.add_flow(table=constants.ARP_RESPONDER,
                                   priority=1,
                                   proto='arp',
                                   dl_vlan=lvid,
                                   nw_dst='%s' % ip,
                                   actions=actions)
          elif action == 'remove':
              self.tun_br.delete_flows(table=constants.ARP_RESPONDER,
                                       proto='arp',
                                       dl_vlan=lvid,
                                       nw_dst='%s' % ip)
          else:
              LOG.warning(_('Action %s not supported'), action)
  
      def provision_local_vlan(self, net_uuid, network_type, physical_network,
                               segmentation_id):
          '''Provisions a local VLAN.
  
          :param net_uuid: the uuid of the network associated with this vlan.
          :param network_type: the network type ('gre', 'vxlan', 'vlan', 'flat',
                                                 'local')
          :param physical_network: the physical network for 'vlan' or 'flat'
          :param segmentation_id: the VID for 'vlan' or tunnel ID for 'tunnel'
          '''
  
          # On a restart or crash of OVS, the network associated with this VLAN
          # will already be assigned, so check for that here before assigning a
          # new one.
          lvm = self.local_vlan_map.get(net_uuid)
          if lvm:
              lvid = lvm.vlan
          else:
              if not self.available_local_vlans:
                  LOG.error(_("No local VLAN available for net-id=%s"), net_uuid)
                  return
              lvid = self.available_local_vlans.pop()
              self.local_vlan_map[net_uuid] = LocalVLANMapping(lvid,
                                                               network_type,
                                                               physical_network,
                                                               segmentation_id)
  
          LOG.info(_("Assigning %(vlan_id)s as local vlan for "
                     "net-id=%(net_uuid)s"),
                   {'vlan_id': lvid, 'net_uuid': net_uuid})
  
          if network_type in constants.TUNNEL_NETWORK_TYPES:
              if self.enable_tunneling:
                  # outbound broadcast/multicast
                  ofports = ','.join(self.tun_br_ofports[network_type].values())
                  if ofports:
                      self.tun_br.mod_flow(table=constants.FLOOD_TO_TUN,
                                           dl_vlan=lvid,
                                           actions="strip_vlan,"
                                           "set_tunnel:%s,output:%s" %
                                           (segmentation_id, ofports))
                  # inbound from tunnels: set lvid in the right table
                  # and resubmit to Table LEARN_FROM_TUN for mac learning
                  if self.enable_distributed_routing:
                      self.dvr_agent.process_tunneled_network(
                          network_type, lvid, segmentation_id)
                  else:
                      self.tun_br.add_flow(
                          table=constants.TUN_TABLE[network_type],
                          priority=1,
                          tun_id=segmentation_id,
                          actions="mod_vlan_vid:%s,"
                          "resubmit(,%s)" %
                          (lvid, constants.LEARN_FROM_TUN))
  
              else:
                  LOG.error(_("Cannot provision %(network_type)s network for "
                            "net-id=%(net_uuid)s - tunneling disabled"),
                            {'network_type': network_type,
                             'net_uuid': net_uuid})
          elif network_type == p_const.TYPE_FLAT:
              if physical_network in self.phys_brs:
                  # outbound
                  br = self.phys_brs[physical_network]
                  br.add_flow(priority=4,
                              in_port=self.phys_ofports[physical_network],
                              dl_vlan=lvid,
                              actions="strip_vlan,normal")
                  # inbound
                  self.int_br.add_flow(
                      priority=3,
                      in_port=self.int_ofports[physical_network],
                      dl_vlan=0xffff,
                      actions="mod_vlan_vid:%s,normal" % lvid)
              else:
                  LOG.error(_("Cannot provision flat network for "
                              "net-id=%(net_uuid)s - no bridge for "
                              "physical_network %(physical_network)s"),
                            {'net_uuid': net_uuid,
                             'physical_network': physical_network})
          elif network_type == p_const.TYPE_VLAN:
              if physical_network in self.phys_brs:
                  # outbound
                  br = self.phys_brs[physical_network]
                  br.add_flow(priority=4,
                              in_port=self.phys_ofports[physical_network],
                              dl_vlan=lvid,
                              actions="mod_vlan_vid:%s,normal" % segmentation_id)
                  # inbound
                  self.int_br.add_flow(priority=3,
                                       in_port=self.
                                       int_ofports[physical_network],
                                       dl_vlan=segmentation_id,
                                       actions="mod_vlan_vid:%s,normal" % lvid)
              else:
                  LOG.error(_("Cannot provision VLAN network for "
                              "net-id=%(net_uuid)s - no bridge for "
                              "physical_network %(physical_network)s"),
                            {'net_uuid': net_uuid,
                             'physical_network': physical_network})
          elif network_type == p_const.TYPE_LOCAL:
              # no flows needed for local networks
              pass
          else:
              LOG.error(_("Cannot provision unknown network type "
                          "%(network_type)s for net-id=%(net_uuid)s"),
                        {'network_type': network_type,
                         'net_uuid': net_uuid})
  
      def reclaim_local_vlan(self, net_uuid):
          '''Reclaim a local VLAN.
  
          :param net_uuid: the network uuid associated with this vlan.
          :param lvm: a LocalVLANMapping object that tracks (vlan, lsw_id,
              vif_ids) mapping.
          '''
          lvm = self.local_vlan_map.pop(net_uuid, None)
          if lvm is None:
              LOG.debug(_("Network %s not used on agent."), net_uuid)
              return
  
          LOG.info(_("Reclaiming vlan = %(vlan_id)s from net-id = %(net_uuid)s"),
                   {'vlan_id': lvm.vlan,
                    'net_uuid': net_uuid})
  
          if lvm.network_type in constants.TUNNEL_NETWORK_TYPES:
              if self.enable_tunneling:
                  self.tun_br.delete_flows(
                      table=constants.TUN_TABLE[lvm.network_type],
                      tun_id=lvm.segmentation_id)
                  self.tun_br.delete_flows(dl_vlan=lvm.vlan)
                  if self.l2_pop:
                      # Try to remove tunnel ports if not used by other networks
                      for ofport in lvm.tun_ofports:
                          self.cleanup_tunnel_port(ofport, lvm.network_type)
          elif lvm.network_type == p_const.TYPE_FLAT:
              if lvm.physical_network in self.phys_brs:
                  # outbound
                  br = self.phys_brs[lvm.physical_network]
                  br.delete_flows(in_port=self.phys_ofports[lvm.
                                                            physical_network],
                                  dl_vlan=lvm.vlan)
                  # inbound
                  br = self.int_br
                  br.delete_flows(in_port=self.int_ofports[lvm.physical_network],
                                  dl_vlan=0xffff)
          elif lvm.network_type == p_const.TYPE_VLAN:
              if lvm.physical_network in self.phys_brs:
                  # outbound
                  br = self.phys_brs[lvm.physical_network]
                  br.delete_flows(in_port=self.phys_ofports[lvm.
                                                            physical_network],
                                  dl_vlan=lvm.vlan)
                  # inbound
                  br = self.int_br
                  br.delete_flows(in_port=self.int_ofports[lvm.physical_network],
                                  dl_vlan=lvm.segmentation_id)
          elif lvm.network_type == p_const.TYPE_LOCAL:
              # no flows needed for local networks
              pass
          else:
              LOG.error(_("Cannot reclaim unknown network type "
                          "%(network_type)s for net-id=%(net_uuid)s"),
                        {'network_type': lvm.network_type,
                         'net_uuid': net_uuid})
  
          self.available_local_vlans.add(lvm.vlan)
  
      def port_bound(self, port, net_uuid,
                     network_type, physical_network,
                     segmentation_id, fixed_ips, device_owner,
                     ovs_restarted):
          '''Bind port to net_uuid/lsw_id and install flow for inbound traffic
          to vm.
  
          :param port: a ovslib.VifPort object.
          :param net_uuid: the net_uuid this port is to be associated with.
          :param network_type: the network type ('gre', 'vlan', 'flat', 'local')
          :param physical_network: the physical network for 'vlan' or 'flat'
          :param segmentation_id: the VID for 'vlan' or tunnel ID for 'tunnel'
          :param fixed_ips: the ip addresses assigned to this port
          :param device_owner: the string indicative of owner of this port
          :param ovs_restarted: indicates if this is called for an OVS restart.
          '''
          if net_uuid not in self.local_vlan_map or ovs_restarted:
              self.provision_local_vlan(net_uuid, network_type,
                                        physical_network, segmentation_id)
          lvm = self.local_vlan_map[net_uuid]
          lvm.vif_ports[port.vif_id] = port
  
          self.dvr_agent.bind_port_to_dvr(port, network_type, fixed_ips,
                                          device_owner,
                                          local_vlan_id=lvm.vlan)
  
          # Do not bind a port if it's already bound
          cur_tag = self.int_br.db_get_val("Port", port.port_name, "tag")
          if cur_tag != str(lvm.vlan):
              self.int_br.set_db_attribute("Port", port.port_name, "tag",
                                           str(lvm.vlan))
              if port.ofport != -1:
                  self.int_br.delete_flows(in_port=port.ofport)
  
      def port_unbound(self, vif_id, net_uuid=None):
          '''Unbind port.
  
          Removes corresponding local vlan mapping object if this is its last
          VIF.
  
          :param vif_id: the id of the vif
          :param net_uuid: the net_uuid this port is associated with.
          '''
          if net_uuid is None:
              net_uuid = self.get_net_uuid(vif_id)
  
          if not self.local_vlan_map.get(net_uuid):
              LOG.info(_('port_unbound(): net_uuid %s not in local_vlan_map'),
                       net_uuid)
              return
  
          lvm = self.local_vlan_map[net_uuid]
  
          if vif_id in lvm.vif_ports:
              vif_port = lvm.vif_ports[vif_id]
              self.dvr_agent.unbind_port_from_dvr(vif_port,
                                                  local_vlan_id=lvm.vlan)
          lvm.vif_ports.pop(vif_id, None)
  
          if not lvm.vif_ports:
              self.reclaim_local_vlan(net_uuid)
  
      def port_dead(self, port):
          '''Once a port has no binding, put it on the "dead vlan".
  
          :param port: a ovs_lib.VifPort object.
          '''
          # Don't kill a port if it's already dead
          cur_tag = self.int_br.db_get_val("Port", port.port_name, "tag")
          if cur_tag != DEAD_VLAN_TAG:
              self.int_br.set_db_attribute("Port", port.port_name, "tag",
                                           DEAD_VLAN_TAG)
              self.int_br.add_flow(priority=2, in_port=port.ofport,
                                   actions="drop")
  
      def setup_integration_br(self):
          '''Setup the integration bridge.
  
          Create patch ports and remove all existing flows.
  
          :param bridge_name: the name of the integration bridge.
          :returns: the integration bridge
          '''
          # Ensure the integration bridge is created.
          # ovs_lib.OVSBridge.create() will run
          #   ovs-vsctl -- --may-exist add-br BRIDGE_NAME
          # which does nothing if bridge already exists.
          self.int_br.create()
          self.int_br.set_secure_mode()
  
          self.int_br.delete_port(cfg.CONF.OVS.int_peer_patch_port)
          self.int_br.remove_all_flows()
          # switch all traffic using L2 learning
          self.int_br.add_flow(priority=1, actions="normal")
          # Add a canary flow to int_br to track OVS restarts
          self.int_br.add_flow(table=constants.CANARY_TABLE, priority=0,
                               actions="drop")
  
      def setup_ancillary_bridges(self, integ_br, tun_br):
          '''Setup ancillary bridges - for example br-ex.'''
          ovs_bridges = set(ovs_lib.get_bridges(self.root_helper))
          # Remove all known bridges
          ovs_bridges.remove(integ_br)
          if self.enable_tunneling:
              ovs_bridges.remove(tun_br)
          br_names = [self.phys_brs[physical_network].br_name for
                      physical_network in self.phys_brs]
          ovs_bridges.difference_update(br_names)
          # Filter list of bridges to those that have external
          # bridge-id's configured
          br_names = []
          for bridge in ovs_bridges:
              id = ovs_lib.get_bridge_external_bridge_id(self.root_helper,
                                                         bridge)
              if id != bridge:
                  br_names.append(bridge)
          ovs_bridges.difference_update(br_names)
          ancillary_bridges = []
          for bridge in ovs_bridges:
              br = ovs_lib.OVSBridge(bridge, self.root_helper)
              LOG.info(_('Adding %s to list of bridges.'), bridge)
              ancillary_bridges.append(br)
          return ancillary_bridges
  
      def setup_tunnel_br(self, tun_br=None):
          '''Setup the tunnel bridge.
  
          Creates tunnel bridge, and links it to the integration bridge
          using a patch port.
  
          :param tun_br: the name of the tunnel bridge.
          '''
          if not self.tun_br:
              self.tun_br = ovs_lib.OVSBridge(tun_br, self.root_helper)
  
          self.tun_br.reset_bridge()
          self.patch_tun_ofport = self.int_br.add_patch_port(
              cfg.CONF.OVS.int_peer_patch_port, cfg.CONF.OVS.tun_peer_patch_port)
          self.patch_int_ofport = self.tun_br.add_patch_port(
              cfg.CONF.OVS.tun_peer_patch_port, cfg.CONF.OVS.int_peer_patch_port)
          if int(self.patch_tun_ofport) < 0 or int(self.patch_int_ofport) < 0:
              LOG.error(_("Failed to create OVS patch port. Cannot have "
                          "tunneling enabled on this agent, since this version "
                          "of OVS does not support tunnels or patch ports. "
                          "Agent terminated!"))
              exit(1)
          self.tun_br.remove_all_flows()
  
          # Table 0 (default) will sort incoming traffic depending on in_port
          self.tun_br.add_flow(priority=1,
                               in_port=self.patch_int_ofport,
                               actions="resubmit(,%s)" %
                               constants.PATCH_LV_TO_TUN)
          self.tun_br.add_flow(priority=0, actions="drop")
          if self.arp_responder_enabled:
              # ARP broadcast-ed request go to the local ARP_RESPONDER table to
              # be locally resolved
              self.tun_br.add_flow(table=constants.PATCH_LV_TO_TUN,
                                   priority=1,
                                   proto='arp',
                                   dl_dst="ff:ff:ff:ff:ff:ff",
                                   actions=("resubmit(,%s)" %
                                            constants.ARP_RESPONDER))
          # PATCH_LV_TO_TUN table will handle packets coming from patch_int
          # unicasts go to table UCAST_TO_TUN where remote addresses are learnt
          self.tun_br.add_flow(table=constants.PATCH_LV_TO_TUN,
                               priority=0,
                               dl_dst="00:00:00:00:00:00/01:00:00:00:00:00",
                               actions="resubmit(,%s)" % constants.UCAST_TO_TUN)
          # Broadcasts/multicasts go to table FLOOD_TO_TUN that handles flooding
          self.tun_br.add_flow(table=constants.PATCH_LV_TO_TUN,
                               priority=0,
                               dl_dst="01:00:00:00:00:00/01:00:00:00:00:00",
                               actions="resubmit(,%s)" % constants.FLOOD_TO_TUN)
          # Tables [tunnel_type]_TUN_TO_LV will set lvid depending on tun_id
          # for each tunnel type, and resubmit to table LEARN_FROM_TUN where
          # remote mac addresses will be learnt
          for tunnel_type in constants.TUNNEL_NETWORK_TYPES:
              self.tun_br.add_flow(table=constants.TUN_TABLE[tunnel_type],
                                   priority=0,
                                   actions="drop")
          # LEARN_FROM_TUN table will have a single flow using a learn action to
          # dynamically set-up flows in UCAST_TO_TUN corresponding to remote mac
          # addresses (assumes that lvid has already been set by a previous flow)
          learned_flow = ("table=%s,"
                          "priority=1,"
                          "hard_timeout=300,"
                          "NXM_OF_VLAN_TCI[0..11],"
                          "NXM_OF_ETH_DST[]=NXM_OF_ETH_SRC[],"
                          "load:0->NXM_OF_VLAN_TCI[],"
                          "load:NXM_NX_TUN_ID[]->NXM_NX_TUN_ID[],"
                          "output:NXM_OF_IN_PORT[]" %
                          constants.UCAST_TO_TUN)
          # Once remote mac addresses are learnt, output packet to patch_int
          self.tun_br.add_flow(table=constants.LEARN_FROM_TUN,
                               priority=1,
                               actions="learn(%s),output:%s" %
                               (learned_flow, self.patch_int_ofport))
          # Egress unicast will be handled in table UCAST_TO_TUN, where remote
          # mac addresses will be learned. For now, just add a default flow that
          # will resubmit unknown unicasts to table FLOOD_TO_TUN to treat them
          # as broadcasts/multicasts
          self.tun_br.add_flow(table=constants.UCAST_TO_TUN,
                               priority=0,
                               actions="resubmit(,%s)" %
                               constants.FLOOD_TO_TUN)
          if self.arp_responder_enabled:
              # If none of the ARP entries correspond to the requested IP, the
              # broadcast-ed packet is resubmitted to the flooding table
              self.tun_br.add_flow(table=constants.ARP_RESPONDER,
                                   priority=0,
                                   actions="resubmit(,%s)" %
                                   constants.FLOOD_TO_TUN)
          # FLOOD_TO_TUN will handle flooding in tunnels based on lvid,
          # for now, add a default drop action
          self.tun_br.add_flow(table=constants.FLOOD_TO_TUN,
                               priority=0,
                               actions="drop")
  
      def get_peer_name(self, prefix, name):
          """Construct a peer name based on the prefix and name.
  
          The peer name can not exceed the maximum length allowed for a linux
          device. Longer names are hashed to help ensure uniqueness.
          """
          if len(prefix + name) <= q_const.DEVICE_NAME_MAX_LEN:
              return prefix + name
          # We can't just truncate because bridges may be distinguished
          # by an ident at the end. A hash over the name should be unique.
          # Leave part of the bridge name on for easier identification
          hashlen = 6
          namelen = q_const.DEVICE_NAME_MAX_LEN - len(prefix) - hashlen
          new_name = ('%(prefix)s%(truncated)s%(hash)s' %
                      {'prefix': prefix, 'truncated': name[0:namelen],
                       'hash': hashlib.sha1(name).hexdigest()[0:hashlen]})
          LOG.warning(_("Creating an interface named %(name)s exceeds the "
                        "%(limit)d character limitation. It was shortened to "
                        "%(new_name)s to fit."),
                      {'name': name, 'limit': q_const.DEVICE_NAME_MAX_LEN,
                       'new_name': new_name})
          return new_name
  
      def setup_physical_bridges(self, bridge_mappings):
          '''Setup the physical network bridges.
  
          Creates physical network bridges and links them to the
          integration bridge using veths.
  
          :param bridge_mappings: map physical network names to bridge names.
          '''
          self.phys_brs = {}
          self.int_ofports = {}
          self.phys_ofports = {}
          ip_wrapper = ip_lib.IPWrapper(self.root_helper)
          ovs_bridges = ovs_lib.get_bridges(self.root_helper)
          for physical_network, bridge in bridge_mappings.iteritems():
              LOG.info(_("Mapping physical network %(physical_network)s to "
                         "bridge %(bridge)s"),
                       {'physical_network': physical_network,
                        'bridge': bridge})
              # setup physical bridge
              if bridge not in ovs_bridges:
                  LOG.error(_("Bridge %(bridge)s for physical network "
                              "%(physical_network)s does not exist. Agent "
                              "terminated!"),
                            {'physical_network': physical_network,
                             'bridge': bridge})
                  sys.exit(1)
              br = ovs_lib.OVSBridge(bridge, self.root_helper)
              br.remove_all_flows()
              br.add_flow(priority=1, actions="normal")
              self.phys_brs[physical_network] = br
  
              # interconnect physical and integration bridges using veth/patchs
              int_if_name = self.get_peer_name(constants.PEER_INTEGRATION_PREFIX,
                                               bridge)
              phys_if_name = self.get_peer_name(constants.PEER_PHYSICAL_PREFIX,
                                                bridge)
              self.int_br.delete_port(int_if_name)
              br.delete_port(phys_if_name)
              if self.use_veth_interconnection:
                  if ip_lib.device_exists(int_if_name, self.root_helper):
                      ip_lib.IPDevice(int_if_name,
                                      self.root_helper).link.delete()
                      # Give udev a chance to process its rules here, to avoid
                      # race conditions between commands launched by udev rules
                      # and the subsequent call to ip_wrapper.add_veth
                      utils.execute(['/sbin/udevadm', 'settle', '--timeout=10'])
                  int_veth, phys_veth = ip_wrapper.add_veth(int_if_name,
                                                            phys_if_name)
                  int_ofport = self.int_br.add_port(int_veth)
                  phys_ofport = br.add_port(phys_veth)
              else:
                  # Create patch ports without associating them in order to block
                  # untranslated traffic before association
                  int_ofport = self.int_br.add_patch_port(
                      int_if_name, constants.NONEXISTENT_PEER)
                  phys_ofport = br.add_patch_port(
                      phys_if_name, constants.NONEXISTENT_PEER)
  
              self.int_ofports[physical_network] = int_ofport
              self.phys_ofports[physical_network] = phys_ofport
  
              # block all untranslated traffic between bridges
              self.int_br.add_flow(priority=2, in_port=int_ofport,
                                   actions="drop")
              br.add_flow(priority=2, in_port=phys_ofport, actions="drop")
  
              if self.use_veth_interconnection:
                  # enable veth to pass traffic
                  int_veth.link.set_up()
                  phys_veth.link.set_up()
                  if self.veth_mtu:
                      # set up mtu size for veth interfaces
                      int_veth.link.set_mtu(self.veth_mtu)
                      phys_veth.link.set_mtu(self.veth_mtu)
              else:
                  # associate patch ports to pass traffic
                  self.int_br.set_db_attribute('Interface', int_if_name,
                                               'options:peer', phys_if_name)
                  br.set_db_attribute('Interface', phys_if_name,
                                      'options:peer', int_if_name)
  
      def scan_ports(self, registered_ports, updated_ports=None):
          cur_ports = self.int_br.get_vif_port_set()
          self.int_br_device_count = len(cur_ports)
          port_info = {'current': cur_ports}
          if updated_ports is None:
              updated_ports = set()
          updated_ports.update(self.check_changed_vlans(registered_ports))
          if updated_ports:
              # Some updated ports might have been removed in the
              # meanwhile, and therefore should not be processed.
              # In this case the updated port won't be found among
              # current ports.
              updated_ports &= cur_ports
              if updated_ports:
                  port_info['updated'] = updated_ports
  
          # FIXME(salv-orlando): It's not really necessary to return early
          # if nothing has changed.
          if cur_ports == registered_ports:
              # No added or removed ports to set, just return here
              return port_info
  
          port_info['added'] = cur_ports - registered_ports
          # Remove all the known ports not found on the integration bridge
          port_info['removed'] = registered_ports - cur_ports
          return port_info
  
      def check_changed_vlans(self, registered_ports):
          """Return ports which have lost their vlan tag.
  
          The returned value is a set of port ids of the ports concerned by a
          vlan tag loss.
          """
          port_tags = self.int_br.get_port_tag_dict()
          changed_ports = set()
          for lvm in self.local_vlan_map.values():
              for port in registered_ports:
                  if (
                      port in lvm.vif_ports
                      and lvm.vif_ports[port].port_name in port_tags
                      and port_tags[lvm.vif_ports[port].port_name] != lvm.vlan
                  ):
                      LOG.info(
                          _("Port '%(port_name)s' has lost "
                              "its vlan tag '%(vlan_tag)d'!"),
                          {'port_name': lvm.vif_ports[port].port_name,
                           'vlan_tag': lvm.vlan}
                      )
                      changed_ports.add(port)
          return changed_ports
  
      def update_ancillary_ports(self, registered_ports):
          ports = set()
          for bridge in self.ancillary_brs:
              ports |= bridge.get_vif_port_set()
  
          if ports == registered_ports:
              return
          added = ports - registered_ports
          removed = registered_ports - ports
          return {'current': ports,
                  'added': added,
                  'removed': removed}
  
      def treat_vif_port(self, vif_port, port_id, network_id, network_type,
                         physical_network, segmentation_id, admin_state_up,
                         fixed_ips, device_owner, ovs_restarted):
          # When this function is called for a port, the port should have
          # an OVS ofport configured, as only these ports were considered
          # for being treated. If that does not happen, it is a potential
          # error condition of which operators should be aware
          if not vif_port.ofport:
              LOG.warn(_("VIF port: %s has no ofport configured, and might not "
                         "be able to transmit"), vif_port.vif_id)
          if vif_port:
              if admin_state_up:
                  self.port_bound(vif_port, network_id, network_type,
                                  physical_network, segmentation_id,
                                  fixed_ips, device_owner, ovs_restarted)
              else:
                  self.port_dead(vif_port)
          else:
              LOG.debug(_("No VIF port for port %s defined on agent."), port_id)
  
      def _setup_tunnel_port(self, port_name, remote_ip, tunnel_type):
          ofport = self.tun_br.add_tunnel_port(port_name,
                                               remote_ip,
                                               self.local_ip,
                                               tunnel_type,
                                               self.vxlan_udp_port,
                                               self.dont_fragment)
          ofport_int = -1
          try:
              ofport_int = int(ofport)
          except (TypeError, ValueError):
              LOG.exception(_("ofport should have a value that can be "
                              "interpreted as an integer"))
          if ofport_int < 0:
              LOG.error(_("Failed to set-up %(type)s tunnel port to %(ip)s"),
                        {'type': tunnel_type, 'ip': remote_ip})
              return 0
  
          self.tun_br_ofports[tunnel_type][remote_ip] = ofport
          # Add flow in default table to resubmit to the right
          # tunnelling table (lvid will be set in the latter)
          self.tun_br.add_flow(priority=1,
                               in_port=ofport,
                               actions="resubmit(,%s)" %
                               constants.TUN_TABLE[tunnel_type])
  
          ofports = ','.join(self.tun_br_ofports[tunnel_type].values())
          if ofports and not self.l2_pop:
              # Update flooding flows to include the new tunnel
              for network_id, vlan_mapping in self.local_vlan_map.iteritems():
                  if vlan_mapping.network_type == tunnel_type:
                      self.tun_br.mod_flow(table=constants.FLOOD_TO_TUN,
                                           dl_vlan=vlan_mapping.vlan,
                                           actions="strip_vlan,"
                                           "set_tunnel:%s,output:%s" %
                                           (vlan_mapping.segmentation_id,
                                            ofports))
          return ofport
  
      def setup_tunnel_port(self, remote_ip, network_type):
          remote_ip_hex = self.get_ip_in_hex(remote_ip)
          if not remote_ip_hex:
              return 0
          port_name = '%s-%s' % (network_type, remote_ip_hex)
          ofport = self._setup_tunnel_port(port_name,
                                           remote_ip,
                                           network_type)
          return ofport
  
      def cleanup_tunnel_port(self, tun_ofport, tunnel_type):
          # Check if this tunnel port is still used
          for lvm in self.local_vlan_map.values():
              if tun_ofport in lvm.tun_ofports:
                  break
          # If not, remove it
          else:
              for remote_ip, ofport in self.tun_br_ofports[tunnel_type].items():
                  if ofport == tun_ofport:
                      port_name = '%s-%s' % (tunnel_type,
                                             self.get_ip_in_hex(remote_ip))
                      self.tun_br.delete_port(port_name)
                      self.tun_br.delete_flows(in_port=ofport)
                      self.tun_br_ofports[tunnel_type].pop(remote_ip, None)
  
      def treat_devices_added_or_updated(self, devices, ovs_restarted):
          skipped_devices = []
          try:
              devices_details_list = self.plugin_rpc.get_devices_details_list(
                  self.context,
                  devices,
                  self.agent_id,
                  cfg.CONF.host)
          except Exception as e:
              raise DeviceListRetrievalError(devices=devices, error=e)
          for details in devices_details_list:
              device = details['device']
              LOG.debug("Processing port: %s", device)
              port = self.int_br.get_vif_port_by_id(device)
              if not port:
                  # The port disappeared and cannot be processed
                  LOG.info(_("Port %s was not found on the integration bridge "
                             "and will therefore not be processed"), device)
                  skipped_devices.append(device)
                  continue
  
              if 'port_id' in details:
                  LOG.info(_("Port %(device)s updated. Details: %(details)s"),
                           {'device': device, 'details': details})
                  self.treat_vif_port(port, details['port_id'],
                                      details['network_id'],
                                      details['network_type'],
                                      details['physical_network'],
                                      details['segmentation_id'],
                                      details['admin_state_up'],
                                      details['fixed_ips'],
                                      details['device_owner'],
                                      ovs_restarted)
                  # update plugin about port status
                  # FIXME(salv-orlando): Failures while updating device status
                  # must be handled appropriately. Otherwise this might prevent
                  # neutron server from sending network-vif-* events to the nova
                  # API server, thus possibly preventing instance spawn.
                  if details.get('admin_state_up'):
                      LOG.debug(_("Setting status for %s to UP"), device)
                      self.plugin_rpc.update_device_up(
                          self.context, device, self.agent_id, cfg.CONF.host)
                  else:
                      LOG.debug(_("Setting status for %s to DOWN"), device)
                      self.plugin_rpc.update_device_down(
                          self.context, device, self.agent_id, cfg.CONF.host)
                  LOG.info(_("Configuration for device %s completed."), device)
              else:
                  LOG.warn(_("Device %s not defined on plugin"), device)
                  if (port and port.ofport != -1):
                      self.port_dead(port)
          return skipped_devices
  
      def treat_ancillary_devices_added(self, devices):
          try:
              devices_details_list = self.plugin_rpc.get_devices_details_list(
                  self.context,
                  devices,
                  self.agent_id,
                  cfg.CONF.host)
          except Exception as e:
              raise DeviceListRetrievalError(devices=devices, error=e)
  
          for details in devices_details_list:
              device = details['device']
              LOG.info(_("Ancillary Port %s added"), device)
  
              # update plugin about port status
              self.plugin_rpc.update_device_up(self.context,
                                               device,
                                               self.agent_id,
                                               cfg.CONF.host)
  
      def treat_devices_removed(self, devices):
          resync = False
          self.sg_agent.remove_devices_filter(devices)
          for device in devices:
              LOG.info(_("Attachment %s removed"), device)
              try:
                  self.plugin_rpc.update_device_down(self.context,
                                                     device,
                                                     self.agent_id,
                                                     cfg.CONF.host)
              except Exception as e:
                  LOG.debug(_("port_removed failed for %(device)s: %(e)s"),
                            {'device': device, 'e': e})
                  resync = True
                  continue
              self.port_unbound(device)
          return resync
  
      def treat_ancillary_devices_removed(self, devices):
          resync = False
          for device in devices:
              LOG.info(_("Attachment %s removed"), device)
              try:
                  details = self.plugin_rpc.update_device_down(self.context,
                                                               device,
                                                               self.agent_id,
                                                               cfg.CONF.host)
              except Exception as e:
                  LOG.debug(_("port_removed failed for %(device)s: %(e)s"),
                            {'device': device, 'e': e})
                  resync = True
                  continue
              if details['exists']:
                  LOG.info(_("Port %s updated."), device)
                  # Nothing to do regarding local networking
              else:
                  LOG.debug(_("Device %s not defined on plugin"), device)
          return resync
  
      def process_network_ports(self, port_info, ovs_restarted):
          resync_a = False
          resync_b = False
          # TODO(salv-orlando): consider a solution for ensuring notifications
          # are processed exactly in the same order in which they were
          # received. This is tricky because there are two notification
          # sources: the neutron server, and the ovs db monitor process
          # If there is an exception while processing security groups ports
          # will not be wired anyway, and a resync will be triggered
          # TODO(salv-orlando): Optimize avoiding applying filters unnecessarily
          # (eg: when there are no IP address changes)
          self.sg_agent.setup_port_filters(port_info.get('added', set()),
                                           port_info.get('updated', set()))
          # VIF wiring needs to be performed always for 'new' devices.
          # For updated ports, re-wiring is not needed in most cases, but needs
          # to be performed anyway when the admin state of a device is changed.
          # A device might be both in the 'added' and 'updated'
          # list at the same time; avoid processing it twice.
          devices_added_updated = (port_info.get('added', set()) |
                                   port_info.get('updated', set()))
          if devices_added_updated:
              start = time.time()
              try:
                  skipped_devices = self.treat_devices_added_or_updated(
                      devices_added_updated, ovs_restarted)
                  LOG.debug(_("process_network_ports - iteration:%(iter_num)d -"
                              "treat_devices_added_or_updated completed. "
                              "Skipped %(num_skipped)d devices of "
                              "%(num_current)d devices currently available. "
                              "Time elapsed: %(elapsed).3f"),
                            {'iter_num': self.iter_num,
                             'num_skipped': len(skipped_devices),
                             'num_current': len(port_info['current']),
                             'elapsed': time.time() - start})
                  # Update the list of current ports storing only those which
                  # have been actually processed.
                  port_info['current'] = (port_info['current'] -
                                          set(skipped_devices))
              except DeviceListRetrievalError:
                  # Need to resync as there was an error with server
                  # communication.
                  LOG.exception(_("process_network_ports - iteration:%d - "
                                  "failure while retrieving port details "
                                  "from server"), self.iter_num)
                  resync_a = True
          if 'removed' in port_info:
              start = time.time()
              resync_b = self.treat_devices_removed(port_info['removed'])
              LOG.debug(_("process_network_ports - iteration:%(iter_num)d -"
                          "treat_devices_removed completed in %(elapsed).3f"),
                        {'iter_num': self.iter_num,
                         'elapsed': time.time() - start})
          # If one of the above operations fails => resync with plugin
          return (resync_a | resync_b)
  
      def process_ancillary_network_ports(self, port_info):
          resync_a = False
          resync_b = False
          if 'added' in port_info:
              start = time.time()
              try:
                  self.treat_ancillary_devices_added(port_info['added'])
                  LOG.debug(_("process_ancillary_network_ports - iteration: "
                              "%(iter_num)d - treat_ancillary_devices_added "
                              "completed in %(elapsed).3f"),
                          {'iter_num': self.iter_num,
                          'elapsed': time.time() - start})
              except DeviceListRetrievalError:
                  # Need to resync as there was an error with server
                  # communication.
                  LOG.exception(_("process_ancillary_network_ports - "
                                  "iteration:%d - failure while retrieving "
                                  "port details from server"), self.iter_num)
                  resync_a = True
          if 'removed' in port_info:
              start = time.time()
              resync_b = self.treat_ancillary_devices_removed(
                  port_info['removed'])
              LOG.debug(_("process_ancillary_network_ports - iteration: "
                          "%(iter_num)d - treat_ancillary_devices_removed "
                          "completed in %(elapsed).3f"),
                        {'iter_num': self.iter_num,
                         'elapsed': time.time() - start})
  
          # If one of the above operations fails => resync with plugin
          return (resync_a | resync_b)
  
      def get_ip_in_hex(self, ip_address):
          try:
              return '%08x' % netaddr.IPAddress(ip_address, version=4)
          except Exception:
              LOG.warn(_("Unable to create tunnel port. Invalid remote IP: %s"),
                       ip_address)
              return
  
      def tunnel_sync(self):
          resync = False
          try:
              for tunnel_type in self.tunnel_types:
                  details = self.plugin_rpc.tunnel_sync(self.context,
                                                        self.local_ip,
                                                        tunnel_type)
                  if not self.l2_pop:
                      tunnels = details['tunnels']
                      for tunnel in tunnels:
                          if self.local_ip != tunnel['ip_address']:
                              tunnel_id = tunnel.get('id')
                              # Unlike the OVS plugin, ML2 doesn't return an id
                              # key. So use ip_address to form port name instead.
                              # Port name must be <=15 chars, so use shorter hex.
                              remote_ip = tunnel['ip_address']
                              remote_ip_hex = self.get_ip_in_hex(remote_ip)
                              if not tunnel_id and not remote_ip_hex:
                                  continue
                              tun_name = '%s-%s' % (tunnel_type,
                                                    tunnel_id or remote_ip_hex)
                              self._setup_tunnel_port(
                                  tun_name, tunnel['ip_address'], tunnel_type)
          except Exception as e:
              LOG.debug(_("Unable to sync tunnel IP %(local_ip)s: %(e)s"),
                        {'local_ip': self.local_ip, 'e': e})
              resync = True
          return resync
  
      def _agent_has_updates(self, polling_manager):
          return (polling_manager.is_polling_required or
                  self.updated_ports or
                  self.sg_agent.firewall_refresh_needed())
  
      def _port_info_has_changes(self, port_info):
          return (port_info.get('added') or
                  port_info.get('removed') or
                  port_info.get('updated'))
  
      def check_ovs_restart(self):
          # Check for the canary flow
          canary_flow = self.int_br.dump_flows_for_table(constants.CANARY_TABLE)
          return not canary_flow
  
      def rpc_loop(self, polling_manager=None):
          if not polling_manager:
              polling_manager = polling.AlwaysPoll()
  
          sync = True
          ports = set()
          updated_ports_copy = set()
          ancillary_ports = set()
          tunnel_sync = True
          ovs_restarted = False
          while self.run_daemon_loop:
              start = time.time()
              port_stats = {'regular': {'added': 0,
                                        'updated': 0,
                                        'removed': 0},
                            'ancillary': {'added': 0,
                                          'removed': 0}}
              LOG.debug(_("Agent rpc_loop - iteration:%d started"),
                        self.iter_num)
              if sync:
                  LOG.info(_("Agent out of sync with plugin!"))
                  ports.clear()
                  ancillary_ports.clear()
                  sync = False
                  polling_manager.force_polling()
              ovs_restarted = self.check_ovs_restart()
              if ovs_restarted:
                  self.setup_integration_br()
                  self.setup_physical_bridges(self.bridge_mappings)
                  if self.enable_tunneling:
                      self.setup_tunnel_br()
                      tunnel_sync = True
                  self.dvr_agent.reset_ovs_parameters(self.int_br,
                                                      self.tun_br,
                                                      self.patch_int_ofport,
                                                      self.patch_tun_ofport)
                  self.dvr_agent.setup_dvr_flows_on_integ_tun_br()
              # Notify the plugin of tunnel IP
              if self.enable_tunneling and tunnel_sync:
                  LOG.info(_("Agent tunnel out of sync with plugin!"))
                  try:
                      tunnel_sync = self.tunnel_sync()
                  except Exception:
                      LOG.exception(_("Error while synchronizing tunnels"))
                      tunnel_sync = True
              if self._agent_has_updates(polling_manager) or ovs_restarted:
                  try:
                      LOG.debug(_("Agent rpc_loop - iteration:%(iter_num)d - "
                                  "starting polling. Elapsed:%(elapsed).3f"),
                                {'iter_num': self.iter_num,
                                 'elapsed': time.time() - start})
                      # Save updated ports dict to perform rollback in
                      # case resync would be needed, and then clear
                      # self.updated_ports. As the greenthread should not yield
                      # between these two statements, this will be thread-safe
                      updated_ports_copy = self.updated_ports
                      self.updated_ports = set()
                      reg_ports = (set() if ovs_restarted else ports)
                      port_info = self.scan_ports(reg_ports, updated_ports_copy)
                      LOG.debug(_("Agent rpc_loop - iteration:%(iter_num)d - "
                                  "port information retrieved. "
                                  "Elapsed:%(elapsed).3f"),
                                {'iter_num': self.iter_num,
                                 'elapsed': time.time() - start})
                      # Secure and wire/unwire VIFs and update their status
                      # on Neutron server
                      if (self._port_info_has_changes(port_info) or
                          self.sg_agent.firewall_refresh_needed() or
                          ovs_restarted):
                          LOG.debug(_("Starting to process devices in:%s"),
                                    port_info)
                          # If treat devices fails - must resync with plugin
                          sync = self.process_network_ports(port_info,
                                                            ovs_restarted)
                          LOG.debug(_("Agent rpc_loop - iteration:%(iter_num)d -"
                                      "ports processed. Elapsed:%(elapsed).3f"),
                                    {'iter_num': self.iter_num,
                                     'elapsed': time.time() - start})
                          port_stats['regular']['added'] = (
                              len(port_info.get('added', [])))
                          port_stats['regular']['updated'] = (
                              len(port_info.get('updated', [])))
                          port_stats['regular']['removed'] = (
                              len(port_info.get('removed', [])))
                      ports = port_info['current']
                      # Treat ancillary devices if they exist
                      if self.ancillary_brs:
                          port_info = self.update_ancillary_ports(
                              ancillary_ports)
                          LOG.debug(_("Agent rpc_loop - iteration:%(iter_num)d -"
                                      "ancillary port info retrieved. "
                                      "Elapsed:%(elapsed).3f"),
                                    {'iter_num': self.iter_num,
                                     'elapsed': time.time() - start})
  
                          if port_info:
                              rc = self.process_ancillary_network_ports(
                                  port_info)
                              LOG.debug(_("Agent rpc_loop - iteration:"
                                          "%(iter_num)d - ancillary ports "
                                          "processed. Elapsed:%(elapsed).3f"),
                                        {'iter_num': self.iter_num,
                                         'elapsed': time.time() - start})
                              ancillary_ports = port_info['current']
                              port_stats['ancillary']['added'] = (
                                  len(port_info.get('added', [])))
                              port_stats['ancillary']['removed'] = (
                                  len(port_info.get('removed', [])))
                              sync = sync | rc
  
                      polling_manager.polling_completed()
                  except Exception:
                      LOG.exception(_("Error while processing VIF ports"))
                      # Put the ports back in self.updated_port
                      self.updated_ports |= updated_ports_copy
                      sync = True
  
              # sleep till end of polling interval
              elapsed = (time.time() - start)
              LOG.debug(_("Agent rpc_loop - iteration:%(iter_num)d "
                          "completed. Processed ports statistics: "
                          "%(port_stats)s. Elapsed:%(elapsed).3f"),
                        {'iter_num': self.iter_num,
                         'port_stats': port_stats,
                         'elapsed': elapsed})
              if (elapsed < self.polling_interval):
                  time.sleep(self.polling_interval - elapsed)
              else:
                  LOG.debug(_("Loop iteration exceeded interval "
                              "(%(polling_interval)s vs. %(elapsed)s)!"),
                            {'polling_interval': self.polling_interval,
                             'elapsed': elapsed})
              self.iter_num = self.iter_num + 1
  
      def daemon_loop(self):
          with polling.get_polling_manager(
              self.minimize_polling,
              self.root_helper,
              self.ovsdb_monitor_respawn_interval) as pm:
  
              self.rpc_loop(polling_manager=pm)
  
      def _handle_sigterm(self, signum, frame):
          LOG.debug("Agent caught SIGTERM, quitting daemon loop.")
          self.run_daemon_loop = False
  
  
  def create_agent_config_map(config):
      """Create a map of agent config parameters.
  
      :param config: an instance of cfg.CONF
      :returns: a map of agent configuration parameters
      """
      try:
          bridge_mappings = q_utils.parse_mappings(config.OVS.bridge_mappings)
      except ValueError as e:
          raise ValueError(_("Parsing bridge_mappings failed: %s.") % e)
  
      kwargs = dict(
          integ_br=config.OVS.integration_bridge,
          tun_br=config.OVS.tunnel_bridge,
          local_ip=config.OVS.local_ip,
          bridge_mappings=bridge_mappings,
          root_helper=config.AGENT.root_helper,
          polling_interval=config.AGENT.polling_interval,
          minimize_polling=config.AGENT.minimize_polling,
          tunnel_types=config.AGENT.tunnel_types,
          veth_mtu=config.AGENT.veth_mtu,
          enable_distributed_routing=config.AGENT.enable_distributed_routing,
          l2_population=config.AGENT.l2_population,
          arp_responder=config.AGENT.arp_responder,
          use_veth_interconnection=config.OVS.use_veth_interconnection,
      )
  
      # If enable_tunneling is TRUE, set tunnel_type to default to GRE
      if config.OVS.enable_tunneling and not kwargs['tunnel_types']:
          kwargs['tunnel_types'] = [p_const.TYPE_GRE]
  
      # Verify the tunnel_types specified are valid
      for tun in kwargs['tunnel_types']:
          if tun not in constants.TUNNEL_NETWORK_TYPES:
              msg = _('Invalid tunnel type specified: %s'), tun
              raise ValueError(msg)
          if not kwargs['local_ip']:
              msg = _('Tunneling cannot be enabled without a valid local_ip.')
              raise ValueError(msg)
  
      return kwargs
  
  
  def main():
      cfg.CONF.register_opts(ip_lib.OPTS)
      common_config.init(sys.argv[1:])
      common_config.setup_logging(cfg.CONF)
      q_utils.log_opt_values(LOG)
  
      try:
          agent_config = create_agent_config_map(cfg.CONF)
      except ValueError as e:
          LOG.error(_('%s Agent terminated!'), e)
          sys.exit(1)
  
      is_xen_compute_host = 'rootwrap-xen-dom0' in agent_config['root_helper']
      if is_xen_compute_host:
          # Force ip_lib to always use the root helper to ensure that ip
          # commands target xen dom0 rather than domU.
          cfg.CONF.set_default('ip_lib_force_root', True)
  
      agent = OVSNeutronAgent(**agent_config)
      signal.signal(signal.SIGTERM, agent._handle_sigterm)
  
      # Start everything.
      LOG.info(_("Agent initialized successfully, now running... "))
      agent.daemon_loop()
  
  
  if __name__ == "__main__":
      main()
  