text: #!/usr/bin/env python
  # vim: tabstop=4 shiftwidth=4 softtabstop=4
  # Copyright 2011 Nicira Networks, 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.
  # @author: Somik Behera, Nicira Networks, Inc.
  # @author: Brad Hall, Nicira Networks, Inc.
  # @author: Dan Wendlandt, Nicira Networks, Inc.
  # @author: Dave Lapsley, Nicira Networks, Inc.
  # @author: Aaron Rosen, Nicira Networks, Inc.
  
  import sys
  import time
  
  import eventlet
  from oslo.config import cfg
  
  from quantum.agent.linux import ip_lib
  from quantum.agent.linux import ovs_lib
  from quantum.agent.linux import utils
  from quantum.agent import rpc as agent_rpc
  from quantum.agent import securitygroups_rpc as sg_rpc
  from quantum.common import config as logging_config
  from quantum.common import constants as q_const
  from quantum.common import topics
  from quantum.common import utils as q_utils
  from quantum import context
  from quantum.extensions import securitygroup as ext_sg
  from quantum.openstack.common import log as logging
  from quantum.openstack.common import loopingcall
  from quantum.openstack.common.rpc import dispatcher
  from quantum.plugins.openvswitch.common import config
  from quantum.plugins.openvswitch.common import constants
  
  
  LOG = logging.getLogger(__name__)
  
  # A placeholder for dead vlans.
  DEAD_VLAN_TAG = "4095"
  
  
  # 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
  
      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 Port(object):
      """Represents a quantum port.
  
      Class stores port data in a ORM-free way, so attributres are
      still available even if a row has been deleted.
      """
  
      def __init__(self, p):
          self.id = p.id
          self.network_id = p.network_id
          self.device_id = p.device_id
          self.admin_state_up = p.admin_state_up
          self.status = p.status
  
      def __eq__(self, other):
          '''Compare only fields that will cause us to re-wire.'''
          try:
              return (self and other
                      and self.id == other.id
                      and self.admin_state_up == other.admin_state_up)
          except:
              return False
  
      def __ne__(self, other):
          return not self.__eq__(other)
  
      def __hash__(self):
          return hash(self.id)
  
  
  class OVSPluginApi(agent_rpc.PluginApi,
                     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()
  
  
  class OVSQuantumAgent(sg_rpc.SecurityGroupAgentRpcCallbackMixin):
      '''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 and 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 networks realized as a VLANs or flat network, a
      veth 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.
      '''
  
      # Lower bound on available vlans.
      MIN_VLAN_TAG = 1
  
      # Upper bound on available vlans.
      MAX_VLAN_TAG = 4094
  
      # history
      #   1.0 Initial version
      #   1.1 Support Security Group RPC
      RPC_API_VERSION = '1.1'
  
      def __init__(self, integ_br, tun_br, local_ip,
                   bridge_mappings, root_helper,
                   polling_interval, enable_tunneling):
          '''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 enable_tunneling: if True enable GRE networks.
          '''
          self.root_helper = root_helper
          self.available_local_vlans = set(
              xrange(OVSQuantumAgent.MIN_VLAN_TAG,
                     OVSQuantumAgent.MAX_VLAN_TAG))
          self.int_br = self.setup_integration_br(integ_br)
          self.setup_physical_bridges(bridge_mappings)
          self.local_vlan_map = {}
  
          self.polling_interval = polling_interval
  
          self.enable_tunneling = enable_tunneling
          self.local_ip = local_ip
          self.tunnel_count = 0
          if self.enable_tunneling:
              self.setup_tunnel_br(tun_br)
          self.agent_state = {
              'binary': 'quantum-openvswitch-agent',
              'host': cfg.CONF.host,
              'topic': q_const.L2_AGENT_TOPIC,
              'configurations': bridge_mappings,
              'agent_type': q_const.AGENT_TYPE_OVS,
              'start_flag': True}
          self.setup_rpc(integ_br)
  
          # Security group agent supprot
          self.sg_agent = OVSSecurityGroupAgent(self.context,
                                                self.plugin_rpc,
                                                root_helper)
  
      def _report_state(self):
          try:
              # How many devices are likely used by a VM
              ports = self.int_br.get_vif_port_set()
              num_devices = len(ports)
              self.agent_state.get('configurations')['devices'] = num_devices
              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, integ_br):
          mac = utils.get_interface_mac(integ_br)
          self.agent_id = '%s%s' % ('ovs', (mac.replace(":", "")))
          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.dispatcher = self.create_rpc_dispatcher()
          # 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]]
          self.connection = agent_rpc.create_consumers(self.dispatcher,
                                                       self.topic,
                                                       consumers)
          report_interval = cfg.CONF.AGENT.report_interval
          if report_interval:
              heartbeat = loopingcall.LoopingCall(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, lvm)
          else:
              LOG.debug(_("Network %s not used on agent."), network_id)
  
      def port_update(self, context, **kwargs):
          LOG.debug(_("port_update received"))
          port = kwargs.get('port')
          # Validate that port is on OVS
          vif_port = self.int_br.get_vif_port_by_id(port['id'])
          if not vif_port:
              return
  
          if ext_sg.SECURITYGROUPS in port:
              self.sg_agent.refresh_firewall()
          network_type = kwargs.get('network_type')
          segmentation_id = kwargs.get('segmentation_id')
          physical_network = kwargs.get('physical_network')
          self.treat_vif_port(vif_port, port['id'], port['network_id'],
                              network_type, physical_network,
                              segmentation_id, port['admin_state_up'])
          if port['admin_state_up']:
              # update plugin about port status
              self.plugin_rpc.update_device_up(self.context, port['id'],
                                               self.agent_id)
          else:
              # update plugin about port status
              self.plugin_rpc.update_device_down(self.context, port['id'],
                                                 self.agent_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')
          if tunnel_ip == self.local_ip:
              return
          tun_name = 'gre-%s' % tunnel_id
          self.tun_br.add_tunnel_port(tun_name, tunnel_ip)
  
      def create_rpc_dispatcher(self):
          '''Get the rpc dispatcher for this manager.
  
          If a manager would like to set an rpc API version, or support more than
          one class as the target of rpc messages, override this method.
          '''
          return dispatcher.RpcDispatcher([self])
  
      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', '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'
          '''
  
          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()
          LOG.info(_("Assigning %(vlan_id)s as local vlan for "
                     "net-id=%(net_uuid)s"),
                   {'vlan_id': lvid, 'net_uuid': net_uuid})
          self.local_vlan_map[net_uuid] = LocalVLANMapping(lvid, network_type,
                                                           physical_network,
                                                           segmentation_id)
  
          if network_type == constants.TYPE_GRE:
              if self.enable_tunneling:
                  # outbound
                  self.tun_br.add_flow(priority=4, in_port=self.patch_int_ofport,
                                       dl_vlan=lvid,
                                       actions="set_tunnel:%s,normal" %
                                       segmentation_id)
                  # inbound bcast/mcast
                  self.tun_br.add_flow(
                      priority=3,
                      tun_id=segmentation_id,
                      dl_dst="01:00:00:00:00:00/01:00:00:00:00:00",
                      actions="mod_vlan_vid:%s,output:%s" %
                      (lvid, self.patch_int_ofport))
              else:
                  LOG.error(_("Cannot provision GRE network for net-id=%s "
                            "- tunneling disabled"), net_uuid)
          elif network_type == constants.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"),
                            locals())
          elif network_type == constants.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"),
                            locals())
          elif network_type == constants.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"),
                        locals())
  
      def reclaim_local_vlan(self, net_uuid, lvm):
          '''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.'''
          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 == constants.TYPE_GRE:
              if self.enable_tunneling:
                  self.tun_br.delete_flows(tun_id=lvm.segmentation_id)
                  self.tun_br.delete_flows(dl_vlan=lvm.vlan)
          elif lvm.network_type == constants.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 == constants.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 == constants.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})
  
          del self.local_vlan_map[net_uuid]
          self.available_local_vlans.add(lvm.vlan)
  
      def port_bound(self, port, net_uuid,
                     network_type, physical_network, segmentation_id):
          '''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'
          '''
          if net_uuid not in self.local_vlan_map:
              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
  
          if network_type == constants.TYPE_GRE:
              if self.enable_tunneling:
                  # inbound unicast
                  self.tun_br.add_flow(priority=3, tun_id=segmentation_id,
                                       dl_dst=port.vif_mac,
                                       actions="mod_vlan_vid:%s,normal" %
                                       lvm.vlan)
  
          self.int_br.set_db_attribute("Port", port.port_name, "tag",
                                       str(lvm.vlan))
          if int(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 lvm.network_type == 'gre':
              if self.enable_tunneling:
                  # remove inbound unicast flow
                  self.tun_br.delete_flows(tun_id=lvm.segmentation_id,
                                           dl_dst=lvm.vif_ports[vif_id].vif_mac)
  
          if vif_id in lvm.vif_ports:
              del lvm.vif_ports[vif_id]
          else:
              LOG.info(_('port_unbound: vif_id %s not in local_vlan_map'),
                       vif_id)
  
          if not lvm.vif_ports:
              self.reclaim_local_vlan(net_uuid, lvm)
  
      def port_dead(self, port):
          '''Once a port has no binding, put it on the "dead vlan".
  
          :param port: a ovs_lib.VifPort object.'''
          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, bridge_name):
          '''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
          '''
          int_br = ovs_lib.OVSBridge(bridge_name, self.root_helper)
          int_br.delete_port(cfg.CONF.OVS.int_peer_patch_port)
          int_br.remove_all_flows()
          # switch all traffic using L2 learning
          int_br.add_flow(priority=1, actions="normal")
          return int_br
  
      def setup_tunnel_br(self, tun_br):
          '''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.'''
          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()
          self.tun_br.add_flow(priority=1, actions="drop")
  
      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)
          for physical_network, bridge in bridge_mappings.iteritems():
              LOG.info(_("Mapping physical network %(physical_network)s to "
                         "bridge %(bridge)s"),
                       locals())
              # setup physical bridge
              if not ip_lib.device_exists(bridge, self.root_helper):
                  LOG.error(_("Bridge %(bridge)s for physical network "
                              "%(physical_network)s does not exist. Agent "
                              "terminated!"),
                            locals())
                  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
  
              # create veth to patch physical bridge with integration bridge
              int_veth_name = constants.VETH_INTEGRATION_PREFIX + bridge
              self.int_br.delete_port(int_veth_name)
              phys_veth_name = constants.VETH_PHYSICAL_PREFIX + bridge
              br.delete_port(phys_veth_name)
              if ip_lib.device_exists(int_veth_name, self.root_helper):
                  ip_lib.IPDevice(int_veth_name, self.root_helper).link.delete()
              int_veth, phys_veth = ip_wrapper.add_veth(int_veth_name,
                                                        phys_veth_name)
              self.int_ofports[physical_network] = self.int_br.add_port(int_veth)
              self.phys_ofports[physical_network] = br.add_port(phys_veth)
  
              # block all untranslated traffic over veth between bridges
              self.int_br.add_flow(priority=2,
                                   in_port=self.int_ofports[physical_network],
                                   actions="drop")
              br.add_flow(priority=2,
                          in_port=self.phys_ofports[physical_network],
                          actions="drop")
  
              # enable veth to pass traffic
              int_veth.link.set_up()
              phys_veth.link.set_up()
  
      def update_ports(self, registered_ports):
          ports = self.int_br.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):
          if vif_port:
              if admin_state_up:
                  self.port_bound(vif_port, network_id, network_type,
                                  physical_network, segmentation_id)
              else:
                  self.port_dead(vif_port)
          else:
              LOG.debug(_("No VIF port for port %s defined on agent."), port_id)
  
      def treat_devices_added(self, devices):
          resync = False
          self.sg_agent.prepare_devices_filter(devices)
          for device in devices:
              LOG.info(_("Port %s added"), device)
              try:
                  details = self.plugin_rpc.get_device_details(self.context,
                                                               device,
                                                               self.agent_id)
              except Exception as e:
                  LOG.debug(_("Unable to get port details for "
                              "%(device)s: %(e)s"), locals())
                  resync = True
                  continue
              port = self.int_br.get_vif_port_by_id(details['device'])
              if 'port_id' in details:
                  LOG.info(_("Port %(device)s updated. Details: %(details)s"),
                           locals())
                  self.treat_vif_port(port, details['port_id'],
                                      details['network_id'],
                                      details['network_type'],
                                      details['physical_network'],
                                      details['segmentation_id'],
                                      details['admin_state_up'])
              else:
                  LOG.debug(_("Device %s not defined on plugin"), device)
                  if (port and int(port.ofport) != -1):
                      self.port_dead(port)
          return resync
  
      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:
                  details = self.plugin_rpc.update_device_down(self.context,
                                                               device,
                                                               self.agent_id)
              except Exception as e:
                  LOG.debug(_("port_removed failed for %(device)s: %(e)s"),
                            locals())
                  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)
                  self.port_unbound(device)
          return resync
  
      def process_network_ports(self, port_info):
          resync_a = False
          resync_b = False
          if 'added' in port_info:
              resync_a = self.treat_devices_added(port_info['added'])
          if 'removed' in port_info:
              resync_b = self.treat_devices_removed(port_info['removed'])
          # If one of the above opertaions fails => resync with plugin
          return (resync_a | resync_b)
  
      def tunnel_sync(self):
          resync = False
          try:
              details = self.plugin_rpc.tunnel_sync(self.context, self.local_ip)
              tunnels = details['tunnels']
              for tunnel in tunnels:
                  if self.local_ip != tunnel['ip_address']:
                      tun_name = 'gre-%s' % tunnel['id']
                      self.tun_br.add_tunnel_port(tun_name, tunnel['ip_address'])
          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 rpc_loop(self):
          sync = True
          ports = set()
          tunnel_sync = True
  
          while True:
              try:
                  start = time.time()
                  if sync:
                      LOG.info(_("Agent out of sync with plugin!"))
                      ports.clear()
                      sync = False
  
                  # Notify the plugin of tunnel IP
                  if self.enable_tunneling and tunnel_sync:
                      LOG.info(_("Agent tunnel out of sync with plugin!"))
                      tunnel_sync = self.tunnel_sync()
  
                  port_info = self.update_ports(ports)
  
                  # notify plugin about port deltas
                  if port_info:
                      LOG.debug(_("Agent loop has new devices!"))
                      # If treat devices fails - must resync with plugin
                      sync = self.process_network_ports(port_info)
                      ports = port_info['current']
  
              except:
                  LOG.exception(_("Error in agent event loop"))
                  sync = True
                  tunnel_sync = True
  
              # sleep till end of polling interval
              elapsed = (time.time() - start)
              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})
  
      def daemon_loop(self):
          self.rpc_loop()
  
  
  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,
          enable_tunneling=config.OVS.enable_tunneling,
      )
  
      if kwargs['enable_tunneling'] and not kwargs['local_ip']:
          msg = _('Tunnelling cannot be enabled without a valid local_ip.')
          raise ValueError(msg)
  
      return kwargs
  
  
  def main():
      eventlet.monkey_patch()
      cfg.CONF(project='quantum')
      logging_config.setup_logging(cfg.CONF)
  
      try:
          agent_config = create_agent_config_map(cfg.CONF)
      except ValueError as e:
          LOG.error(_('%s Agent terminated!'), e)
          sys.exit(1)
  
      plugin = OVSQuantumAgent(**agent_config)
  
      # Start everything.
      LOG.info(_("Agent initialized successfully, now running... "))
      plugin.daemon_loop()
      sys.exit(0)
  
  
  if __name__ == "__main__":
      main()
  