# Copyright 2012 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 functools
import random

import netaddr
from neutron_lib.api.definitions import external_net as extnet_apidef
from neutron_lib.api.definitions import l3 as l3_apidef
from neutron_lib.api.definitions import portbindings as pb
from neutron_lib.api import validators
from neutron_lib.callbacks import events
from neutron_lib.callbacks import exceptions
from neutron_lib.callbacks import registry
from neutron_lib.callbacks import resources
from neutron_lib import constants
from neutron_lib import context as n_ctx
from neutron_lib import exceptions as n_exc
from neutron_lib.exceptions import l3 as l3_exc
from neutron_lib.plugins import constants as plugin_constants
from neutron_lib.plugins import directory
from neutron_lib.services import base as base_services
from oslo_log import log as logging
from oslo_utils import uuidutils
from sqlalchemy import orm
from sqlalchemy.orm import exc

from neutron._i18n import _
from neutron.api.rpc.agentnotifiers import l3_rpc_agent_api
from neutron.common import ipv6_utils
from neutron.common import rpc as n_rpc
from neutron.common import utils
from neutron.db import _model_query as model_query
from neutron.db import _resource_extend as resource_extend
from neutron.db import _utils as db_utils
from neutron.db import api as db_api
from neutron.db import common_db_mixin
from neutron.db.models import l3 as l3_models
from neutron.db import models_v2
from neutron.db import standardattrdescription_db as st_attr
from neutron.extensions import l3
from neutron.extensions import qos_fip
from neutron.objects import base as base_obj
from neutron.objects import ports as port_obj
from neutron.objects import router as l3_obj
from neutron.plugins.common import utils as p_utils
from neutron import worker as neutron_worker

LOG = logging.getLogger(__name__)


DEVICE_OWNER_HA_REPLICATED_INT = constants.DEVICE_OWNER_HA_REPLICATED_INT
DEVICE_OWNER_ROUTER_INTF = constants.DEVICE_OWNER_ROUTER_INTF
DEVICE_OWNER_ROUTER_GW = constants.DEVICE_OWNER_ROUTER_GW
DEVICE_OWNER_FLOATINGIP = constants.DEVICE_OWNER_FLOATINGIP
EXTERNAL_GW_INFO = l3_apidef.EXTERNAL_GW_INFO

# Maps API field to DB column
# API parameter name and Database column names may differ.
# Useful to keep the filtering between API and Database.
API_TO_DB_COLUMN_MAP = {'port_id': 'fixed_port_id'}
CORE_ROUTER_ATTRS = ('id', 'name', 'tenant_id', 'admin_state_up', 'status')


def can_port_be_bound_to_virtual_bridge(port):
    """Returns if port can be bound to a virtual bridge (e.g.: LB, OVS)

    :param port: (dict) A port dictionary.
    :returns: True if the port VNIC type is 'normal'; False in any other case.
    """
    return port[pb.VNIC_TYPE] == pb.VNIC_NORMAL


@registry.has_registry_receivers
class L3_NAT_dbonly_mixin(l3.RouterPluginBase,
                          base_services.WorkerBase,
                          st_attr.StandardAttrDescriptionMixin):
    """Mixin class to add L3/NAT router methods to db_base_plugin_v2."""

    router_device_owners = (
        DEVICE_OWNER_HA_REPLICATED_INT,
        DEVICE_OWNER_ROUTER_INTF,
        DEVICE_OWNER_ROUTER_GW,
        DEVICE_OWNER_FLOATINGIP
    )

    _dns_integration = None

    _fip_qos = None

    def __new__(cls, *args, **kwargs):
        inst = super(L3_NAT_dbonly_mixin, cls).__new__(cls, *args, **kwargs)
        inst._start_janitor()
        return inst

    @staticmethod
    @registry.receives(resources.PORT, [events.BEFORE_DELETE])
    def _prevent_l3_port_delete_callback(resource, event, trigger, **kwargs):
        context = kwargs['context']
        port_id = kwargs['port_id']
        port_check = kwargs['port_check']
        l3plugin = directory.get_plugin(plugin_constants.L3)
        if l3plugin and port_check:
            l3plugin.prevent_l3_port_deletion(context, port_id)

    @property
    def _is_dns_integration_supported(self):
        if self._dns_integration is None:
            self._dns_integration = (
                utils.is_extension_supported(self._core_plugin,
                    'dns-integration') or
                utils.is_extension_supported(self._core_plugin,
                    'dns-domain-ports'))
        return self._dns_integration

    @property
    def _is_fip_qos_supported(self):
        if self._fip_qos is None:
            # Check L3 service plugin
            self._fip_qos = utils.is_extension_supported(
                self, qos_fip.FIP_QOS_ALIAS)
        return self._fip_qos

    @property
    def _core_plugin(self):
        return directory.get_plugin()

    def _start_janitor(self):
        """Starts the periodic job that cleans up broken complex resources.

        This job will look for things like floating IP ports without an
        associated floating IP and delete them 5 minutes after detection.
        """
        interval = 60 * 5  # only every 5 minutes. cleanups should be rare
        initial_delay = random.randint(0, interval)  # splay multiple servers
        janitor = neutron_worker.PeriodicWorker(self._clean_garbage, interval,
                                                initial_delay)
        self.add_worker(janitor)

    def _clean_garbage(self):
        if not hasattr(self, '_candidate_broken_fip_ports'):
            self._candidate_broken_fip_ports = set()
        context = n_ctx.get_admin_context()
        candidates = self._get_dead_floating_port_candidates(context)
        # just because a port is in 'candidates' doesn't necessarily mean
        # it's broken, we could have just caught it before it was updated.
        # We confirm by waiting until the next call of this function to see
        # if it persists.
        to_cleanup = candidates & self._candidate_broken_fip_ports
        self._candidate_broken_fip_ports = candidates - to_cleanup
        for port_id in to_cleanup:
            # ensure it wasn't just a failure to update device_id before we
            # delete it
            try:
                self._fix_or_kill_floating_port(context, port_id)
            except Exception:
                LOG.exception("Error cleaning up floating IP port: %s",
                              port_id)

    def _fix_or_kill_floating_port(self, context, port_id):
        pager = base_obj.Pager(limit=1)
        fips = l3_obj.FloatingIP.get_objects(
            context, _pager=pager, floating_port_id=port_id)
        if fips:
            LOG.warning("Found incorrect device_id on floating port "
                        "%(pid)s, correcting to %(fip)s.",
                        {'pid': port_id, 'fip': fips[0].id})
            self._core_plugin.update_port(
                context, port_id, {'port': {'device_id': fips[0].id}})
        else:
            LOG.warning("Found floating IP port %s without floating IP, "
                        "deleting.", port_id)
            self._core_plugin.delete_port(
                context, port_id, l3_port_check=False)
            registry.notify(resources.FLOATING_IP, events.AFTER_DELETE,
                            self, **fips[0])

    def _get_dead_floating_port_candidates(self, context):
        filters = {'device_id': ['PENDING'],
                   'device_owner': [DEVICE_OWNER_FLOATINGIP]}
        return {p['id'] for p in self._core_plugin.get_ports(context, filters)}

    def _get_router(self, context, router_id):
        try:
            router = model_query.get_by_id(
                context, l3_models.Router, router_id)
        except exc.NoResultFound:
            raise l3_exc.RouterNotFound(router_id=router_id)
        return router

    def _make_router_dict(self, router, fields=None, process_extensions=True):
        res = dict((key, router[key]) for key in CORE_ROUTER_ATTRS)
        if router['gw_port_id']:
            ext_gw_info = {
                'network_id': router.gw_port['network_id'],
                'external_fixed_ips': [{'subnet_id': ip["subnet_id"],
                                        'ip_address': ip["ip_address"]}
                                       for ip in router.gw_port['fixed_ips']]}
        else:
            ext_gw_info = None
        res.update({
            EXTERNAL_GW_INFO: ext_gw_info,
            'gw_port_id': router['gw_port_id'],
        })
        # NOTE(salv-orlando): The following assumes this mixin is used in a
        # class inheriting from CommonDbMixin, which is true for all existing
        # plugins.
        if process_extensions:
            resource_extend.apply_funcs(l3_apidef.ROUTERS, res, router)
        return db_utils.resource_fields(res, fields)

    def _create_router_db(self, context, router, tenant_id):
        """Create the DB object."""
        router.setdefault('id', uuidutils.generate_uuid())
        router['tenant_id'] = tenant_id
        registry.notify(resources.ROUTER, events.BEFORE_CREATE,
                        self, context=context, router=router)
        with context.session.begin(subtransactions=True):
            # pre-generate id so it will be available when
            # configuring external gw port
            router_db = l3_models.Router(
                id=router['id'],
                tenant_id=router['tenant_id'],
                name=router['name'],
                admin_state_up=router['admin_state_up'],
                status=constants.ACTIVE,
                description=router.get('description'))
            context.session.add(router_db)
            registry.notify(resources.ROUTER, events.PRECOMMIT_CREATE,
                            self, context=context, router=router,
                            router_id=router['id'], router_db=router_db)
            return router_db

    def _update_gw_for_create_router(self, context, gw_info, router_id):
        if gw_info:
            router_db = self._get_router(context, router_id)
            self._update_router_gw_info(context, router_id,
                                        gw_info, router=router_db)

    @db_api.retry_if_session_inactive()
    def create_router(self, context, router):
        r = router['router']
        gw_info = r.pop(EXTERNAL_GW_INFO, None)
        create = functools.partial(self._create_router_db, context, r,
                                   r['tenant_id'])
        delete = functools.partial(self.delete_router, context)
        update_gw = functools.partial(self._update_gw_for_create_router,
                                      context, gw_info)
        router_db, _unused = common_db_mixin.safe_creation(context, create,
                                                           delete, update_gw,
                                                           transaction=False)
        new_router = self._make_router_dict(router_db)
        registry.notify(resources.ROUTER, events.AFTER_CREATE, self,
                        context=context, router_id=router_db.id,
                        router=new_router, request_attrs=r,
                        router_db=router_db)
        return new_router

    def _update_router_db(self, context, router_id, data):
        """Update the DB object."""
        with context.session.begin(subtransactions=True):
            router_db = self._get_router(context, router_id)
            old_router = self._make_router_dict(router_db)
            if data:
                router_db.update(data)
            registry.publish(resources.ROUTER, events.PRECOMMIT_UPDATE, self,
                             payload=events.DBEventPayload(
                                 context, request_body=data,
                                 states=(old_router,), resource_id=router_id,
                                 desired_state=router_db))
            return router_db

    @db_api.retry_if_session_inactive()
    def update_router(self, context, id, router):
        r = router['router']
        gw_info = r.pop(EXTERNAL_GW_INFO, constants.ATTR_NOT_SPECIFIED)
        original = self.get_router(context, id)
        # check whether router needs and can be rescheduled to the proper
        # l3 agent (associated with given external network);
        # do check before update in DB as an exception will be raised
        # in case no proper l3 agent found
        if gw_info != constants.ATTR_NOT_SPECIFIED:
            candidates = self._check_router_needs_rescheduling(
                context, id, gw_info)
            # Update the gateway outside of the DB update since it involves L2
            # calls that don't make sense to rollback and may cause deadlocks
            # in a transaction.
            self._update_router_gw_info(context, id, gw_info)
        else:
            candidates = None
        router_db = self._update_router_db(context, id, r)
        if candidates:
            l3_plugin = directory.get_plugin(plugin_constants.L3)
            l3_plugin.reschedule_router(context, id, candidates)
        updated = self._make_router_dict(router_db)
        registry.notify(resources.ROUTER, events.AFTER_UPDATE, self,
                        context=context, router_id=id, old_router=original,
                        router=updated, request_attrs=r, router_db=router_db)
        return updated

    def _check_router_needs_rescheduling(self, context, router_id, gw_info):
        """Checks whether router's l3 agent can handle the given network

        When external_network_bridge is set, each L3 agent can be associated
        with at most one external network. If router's new external gateway
        is on other network then the router needs to be rescheduled to the
        proper l3 agent.
        If external_network_bridge is not set then the agent
        can support multiple external networks and rescheduling is not needed

        :return: list of candidate agents if rescheduling needed,
        None otherwise; raises exception if there is no eligible l3 agent
        associated with target external network
        """
        # TODO(obondarev): rethink placement of this func as l3 db manager is
        # not really a proper place for agent scheduling stuff
        network_id = gw_info.get('network_id') if gw_info else None
        if not network_id:
            return

        nets = self._core_plugin.get_networks(
            context, {extnet_apidef.EXTERNAL: [True]})
        # nothing to do if there is only one external network
        if len(nets) <= 1:
            return

        # first get plugin supporting l3 agent scheduling
        # (either l3 service plugin or core_plugin)
        l3_plugin = directory.get_plugin(plugin_constants.L3)
        if (not utils.is_extension_supported(
                l3_plugin,
                constants.L3_AGENT_SCHEDULER_EXT_ALIAS) or
            l3_plugin.router_scheduler is None):
            # that might mean that we are dealing with non-agent-based
            # implementation of l3 services
            return

        if not l3_plugin.router_supports_scheduling(context, router_id):
            return
        cur_agents = l3_plugin.list_l3_agents_hosting_router(
            context, router_id)['agents']
        for agent in cur_agents:
            ext_net_id = agent['configurations'].get(
                'gateway_external_network_id')
            ext_bridge = agent['configurations'].get(
                'external_network_bridge', '')
            if (ext_net_id == network_id or
                    (not ext_net_id and not ext_bridge)):
                return

        # otherwise find l3 agent with matching gateway_external_network_id
        active_agents = l3_plugin.get_l3_agents(context, active=True)
        router = {
            'id': router_id,
            'external_gateway_info': {'network_id': network_id}
        }
        candidates = l3_plugin.get_l3_agent_candidates(context,
                                                       router,
                                                       active_agents)
        if not candidates:
            msg = (_('No eligible l3 agent associated with external network '
                     '%s found') % network_id)
            raise n_exc.BadRequest(resource='router', msg=msg)

        return candidates

    def _create_router_gw_port(self, context, router, network_id, ext_ips):
        # Port has no 'tenant-id', as it is hidden from user
        port_data = {'tenant_id': '',  # intentionally not set
                     'network_id': network_id,
                     'fixed_ips': ext_ips or constants.ATTR_NOT_SPECIFIED,
                     'device_id': router['id'],
                     'device_owner': DEVICE_OWNER_ROUTER_GW,
                     'admin_state_up': True,
                     'name': ''}
        gw_port = p_utils.create_port(self._core_plugin,
                                      context.elevated(), {'port': port_data})

        if not gw_port['fixed_ips']:
            LOG.debug('No IPs available for external network %s',
                      network_id)
        with p_utils.delete_port_on_error(self._core_plugin,
                                          context.elevated(), gw_port['id']):
            with context.session.begin(subtransactions=True):
                router.gw_port = self._core_plugin._get_port(
                    context.elevated(), gw_port['id'])
                router_port = l3_obj.RouterPort(
                    context,
                    router_id=router.id,
                    port_id=gw_port['id'],
                    port_type=DEVICE_OWNER_ROUTER_GW
                )
                context.session.add(router)
                router_port.create()

    def _validate_gw_info(self, context, gw_port, info, ext_ips):
        network_id = info['network_id'] if info else None
        if network_id:
            network_db = self._core_plugin._get_network(context, network_id)
            if not network_db.external:
                msg = _("Network %s is not an external network") % network_id
                raise n_exc.BadRequest(resource='router', msg=msg)
            if ext_ips:
                subnets = self._core_plugin.get_subnets_by_network(context,
                                                                   network_id)
                for s in subnets:
                    if not s['gateway_ip']:
                        continue
                    for ext_ip in ext_ips:
                        if ext_ip.get('ip_address') == s['gateway_ip']:
                            msg = _("External IP %s is the same as the "
                                    "gateway IP") % ext_ip.get('ip_address')
                            raise n_exc.BadRequest(resource='router', msg=msg)
        return network_id

    # NOTE(yamamoto): This method is an override point for plugins
    # inheriting this class.  Do not optimize this out.
    def router_gw_port_has_floating_ips(self, context, router_id):
        """Return True if the router's gateway port is serving floating IPs."""
        return bool(self.get_floatingips_count(context,
                                               {'router_id': [router_id]}))

    def _delete_current_gw_port(self, context, router_id, router,
                                new_network_id):
        """Delete gw port if attached to an old network."""
        port_requires_deletion = (
            router.gw_port and router.gw_port['network_id'] != new_network_id)
        if not port_requires_deletion:
            return
        admin_ctx = context.elevated()
        old_network_id = router.gw_port['network_id']

        if self.router_gw_port_has_floating_ips(admin_ctx, router_id):
            raise l3_exc.RouterExternalGatewayInUseByFloatingIp(
                router_id=router_id, net_id=router.gw_port['network_id'])
        gw_ips = [x['ip_address'] for x in router.gw_port['fixed_ips']]
        gw_port_id = router.gw_port['id']
        self._delete_router_gw_port_db(context, router)
        self._core_plugin.delete_port(
            admin_ctx, gw_port_id, l3_port_check=False)
        with context.session.begin(subtransactions=True):
            context.session.refresh(router)
        registry.notify(resources.ROUTER_GATEWAY,
                        events.AFTER_DELETE, self,
                        router_id=router_id,
                        context=context,
                        router=router,
                        network_id=old_network_id,
                        new_network_id=new_network_id,
                        gateway_ips=gw_ips)

    def _delete_router_gw_port_db(self, context, router):
        with context.session.begin(subtransactions=True):
            router.gw_port = None
            if router not in context.session:
                context.session.add(router)
            try:
                kwargs = {'context': context, 'router_id': router.id}
                registry.notify(
                    resources.ROUTER_GATEWAY, events.BEFORE_DELETE, self,
                    **kwargs)
            except exceptions.CallbackFailure as e:
                # NOTE(armax): preserve old check's behavior
                if len(e.errors) == 1:
                    raise e.errors[0].error
                raise l3_exc.RouterInUse(router_id=router.id, reason=e)

    def _create_gw_port(self, context, router_id, router, new_network_id,
                        ext_ips):
        new_valid_gw_port_attachment = (
            new_network_id and (not router.gw_port or
                              router.gw_port['network_id'] != new_network_id))
        if new_valid_gw_port_attachment:
            subnets = self._core_plugin.get_subnets_by_network(context,
                                                               new_network_id)
            try:
                kwargs = {'context': context, 'router_id': router_id,
                          'network_id': new_network_id, 'subnets': subnets}
                registry.notify(
                    resources.ROUTER_GATEWAY, events.BEFORE_CREATE, self,
                    **kwargs)
            except exceptions.CallbackFailure as e:
                # raise the underlying exception
                raise e.errors[0].error

            self._check_for_dup_router_subnets(context, router,
                                               new_network_id,
                                               subnets,
                                               include_gateway=True)
            self._create_router_gw_port(context, router,
                                        new_network_id, ext_ips)
            registry.notify(resources.ROUTER_GATEWAY,
                            events.AFTER_CREATE,
                            self._create_gw_port,
                            gw_ips=ext_ips,
                            network_id=new_network_id,
                            router_id=router_id)

    def _update_current_gw_port(self, context, router_id, router, ext_ips):
        self._core_plugin.update_port(context, router.gw_port['id'], {'port':
                                      {'fixed_ips': ext_ips}})
        context.session.expire(router.gw_port)

    def _update_router_gw_info(self, context, router_id, info, router=None):
        # TODO(salvatore-orlando): guarantee atomic behavior also across
        # operations that span beyond the model classes handled by this
        # class (e.g.: delete_port)
        router = router or self._get_router(context, router_id)
        gw_port = router.gw_port
        ext_ips = info.get('external_fixed_ips') if info else []
        ext_ip_change = self._check_for_external_ip_change(
            context, gw_port, ext_ips)
        network_id = self._validate_gw_info(context, gw_port, info, ext_ips)
        if gw_port and ext_ip_change and gw_port['network_id'] == network_id:
            self._update_current_gw_port(context, router_id, router,
                                         ext_ips)
        else:
            self._delete_current_gw_port(context, router_id, router,
                                         network_id)
            self._create_gw_port(context, router_id, router, network_id,
                                 ext_ips)

    def _check_for_external_ip_change(self, context, gw_port, ext_ips):
        # determine if new external IPs differ from the existing fixed_ips
        if not ext_ips:
            # no external_fixed_ips were included
            return False
        if not gw_port:
            return True

        subnet_ids = set(ip['subnet_id'] for ip in gw_port['fixed_ips'])
        new_subnet_ids = set(f['subnet_id'] for f in ext_ips
                             if f.get('subnet_id'))
        subnet_change = not new_subnet_ids == subnet_ids
        if subnet_change:
            return True
        ip_addresses = set(ip['ip_address'] for ip in gw_port['fixed_ips'])
        new_ip_addresses = set(f['ip_address'] for f in ext_ips
                               if f.get('ip_address'))
        ip_address_change = not ip_addresses == new_ip_addresses
        return ip_address_change

    def _ensure_router_not_in_use(self, context, router_id):
        """Ensure that no internal network interface is attached
        to the router.
        """
        router = self._get_router(context, router_id)
        device_owner = self._get_device_owner(context, router)
        if any(rp.port_type == device_owner
               for rp in router.attached_ports):
            raise l3_exc.RouterInUse(router_id=router_id)
        return router

    @db_api.retry_if_session_inactive()
    def delete_router(self, context, id):
        registry.notify(resources.ROUTER, events.BEFORE_DELETE,
                        self, context=context, router_id=id)
        #TODO(nati) Refactor here when we have router insertion model
        router = self._ensure_router_not_in_use(context, id)
        original = self._make_router_dict(router)
        self._delete_current_gw_port(context, id, router, None)
        with context.session.begin(subtransactions=True):
            context.session.refresh(router)

        router_ports = router.attached_ports
        for rp in router_ports:
            self._core_plugin.delete_port(context.elevated(),
                                          rp.port.id,
                                          l3_port_check=False)
        with context.session.begin(subtransactions=True):
            context.session.refresh(router)
            registry.notify(resources.ROUTER, events.PRECOMMIT_DELETE,
                            self, context=context, router_db=router,
                            router_id=id)
            # we bump the revision even though we are about to delete to throw
            # staledataerror if something snuck in with a new interface
            router.bump_revision()
            context.session.flush()
            context.session.delete(router)
        registry.notify(resources.ROUTER, events.AFTER_DELETE, self,
                        context=context, router_id=id, original=original)

    @db_api.retry_if_session_inactive()
    def get_router(self, context, id, fields=None):
        router = self._get_router(context, id)
        return self._make_router_dict(router, fields)

    @db_api.retry_if_session_inactive()
    def get_routers(self, context, filters=None, fields=None,
                    sorts=None, limit=None, marker=None,
                    page_reverse=False):
        marker_obj = db_utils.get_marker_obj(self, context, 'router',
                                             limit, marker)
        return model_query.get_collection(context, l3_models.Router,
                                          self._make_router_dict,
                                          filters=filters, fields=fields,
                                          sorts=sorts,
                                          limit=limit,
                                          marker_obj=marker_obj,
                                          page_reverse=page_reverse)

    @db_api.retry_if_session_inactive()
    def get_routers_count(self, context, filters=None):
        return model_query.get_collection_count(context, l3_models.Router,
                                                filters=filters)

    def _check_for_dup_router_subnets(self, context, router,
                                      network_id, new_subnets,
                                      include_gateway=False):
        # It's possible these ports are on the same network, but
        # different subnets.
        new_subnet_ids = {s['id'] for s in new_subnets}
        router_subnets = []
        for p in (rp.port for rp in router.attached_ports):
            for ip in p['fixed_ips']:
                if ip['subnet_id'] in new_subnet_ids:
                    msg = (_("Router already has a port on subnet %s")
                           % ip['subnet_id'])
                    raise n_exc.BadRequest(resource='router', msg=msg)
                gw_owner = (p.get('device_owner') == DEVICE_OWNER_ROUTER_GW)
                if include_gateway == gw_owner:
                    router_subnets.append(ip['subnet_id'])

        # Ignore temporary Prefix Delegation CIDRs
        new_subnets = [s for s in new_subnets
                       if s['cidr'] != constants.PROVISIONAL_IPV6_PD_PREFIX]
        id_filter = {'id': router_subnets}
        subnets = self._core_plugin.get_subnets(context.elevated(),
                                                filters=id_filter)
        for sub in subnets:
            cidr = sub['cidr']
            ipnet = netaddr.IPNetwork(cidr)
            for s in new_subnets:
                new_cidr = s['cidr']
                new_ipnet = netaddr.IPNetwork(new_cidr)
                match1 = netaddr.all_matching_cidrs(new_ipnet, [cidr])
                match2 = netaddr.all_matching_cidrs(ipnet, [new_cidr])
                if match1 or match2:
                    data = {'subnet_cidr': new_cidr,
                            'subnet_id': s['id'],
                            'cidr': cidr,
                            'sub_id': sub['id']}
                    msg = (_("Cidr %(subnet_cidr)s of subnet "
                             "%(subnet_id)s overlaps with cidr %(cidr)s "
                             "of subnet %(sub_id)s") % data)
                    raise n_exc.BadRequest(resource='router', msg=msg)

    def _get_device_owner(self, context, router=None):
        """Get device_owner for the specified router."""
        # NOTE(armando-migliaccio): in the base case this is invariant
        return DEVICE_OWNER_ROUTER_INTF

    def _validate_interface_info(self, interface_info, for_removal=False):
        port_id_specified = interface_info and 'port_id' in interface_info
        subnet_id_specified = interface_info and 'subnet_id' in interface_info
        if not (port_id_specified or subnet_id_specified):
            msg = _("Either subnet_id or port_id must be specified")
            raise n_exc.BadRequest(resource='router', msg=msg)
        for key in ('port_id', 'subnet_id'):
            if key not in interface_info:
                continue
            err = validators.validate_uuid(interface_info[key])
            if err:
                raise n_exc.BadRequest(resource='router', msg=err)
        if not for_removal:
            if port_id_specified and subnet_id_specified:
                msg = _("Cannot specify both subnet-id and port-id")
                raise n_exc.BadRequest(resource='router', msg=msg)
        return port_id_specified, subnet_id_specified

    def _check_router_port(self, context, port_id, device_id):
        """Check that a port is available for an attachment to a router

        :param context: The context of the request.
        :param port_id: The port to be attached.
        :param device_id: This method will check that device_id corresponds to
        the device_id of the port. It raises PortInUse exception if it
        doesn't.
        :returns: The port description returned by the core plugin.
        :raises: PortInUse if the device_id is not the same as the port's one.
        :raises: BadRequest if the port has no fixed IP.
        """
        port = self._core_plugin.get_port(context, port_id)
        if port['device_id'] != device_id:
            raise n_exc.PortInUse(net_id=port['network_id'],
                                  port_id=port['id'],
                                  device_id=port['device_id'])
        if not port['fixed_ips']:
            msg = _('Router port must have at least one fixed IP')
            raise n_exc.BadRequest(resource='router', msg=msg)
        return port

    def _validate_port_in_range_or_admin(self, context, subnets, port):
        if context.is_admin:
            return
        subnets_by_id = {}
        for s in subnets:
            addr_set = netaddr.IPSet()
            for range in s['allocation_pools']:
                addr_set.add(netaddr.IPRange(netaddr.IPAddress(range['start']),
                                             netaddr.IPAddress(range['end'])))
            subnets_by_id[s['id']] = (addr_set, s['project_id'],)
        for subnet_id, ip in [(fix_ip['subnet_id'], fix_ip['ip_address'],)
                              for fix_ip in port['fixed_ips']]:
            if (ip not in subnets_by_id[subnet_id][0] and
                    context.project_id != subnets_by_id[subnet_id][1]):
                msg = (_('Cannot add interface to router because specified '
                         'port %(port)s has an IP address out of the '
                         'allocation pool of subnet %(subnet)s, which is not '
                         'owned by the project making the request') %
                       {'port': port['id'], 'subnet': subnet_id})
                raise n_exc.BadRequest(resource='router', msg=msg)

    def _validate_router_port_info(self, context, router, port_id):
        with db_api.autonested_transaction(context.session):
            # check again within transaction to mitigate race
            port = self._check_router_port(context, port_id, router.id)

            # Only allow one router port with IPv6 subnets per network id
            if self._port_has_ipv6_address(port):
                for existing_port in (rp.port for rp in router.attached_ports):
                    if (existing_port['network_id'] == port['network_id'] and
                            self._port_has_ipv6_address(existing_port)):
                        msg = _("Cannot have multiple router ports with the "
                                "same network id if both contain IPv6 "
                                "subnets. Existing port %(p)s has IPv6 "
                                "subnet(s) and network id %(nid)s")
                        raise n_exc.BadRequest(resource='router', msg=msg % {
                            'p': existing_port['id'],
                            'nid': existing_port['network_id']})

            fixed_ips = [ip for ip in port['fixed_ips']]
            subnets = []
            for fixed_ip in fixed_ips:
                subnet = self._core_plugin.get_subnet(context,
                                                      fixed_ip['subnet_id'])
                subnets.append(subnet)

            if subnets:
                self._check_for_dup_router_subnets(context, router,
                                                   port['network_id'],
                                                   subnets)

            # Keep the restriction against multiple IPv4 subnets
            if len([s for s in subnets if s['ip_version'] == 4]) > 1:
                msg = _("Cannot have multiple "
                        "IPv4 subnets on router port")
                raise n_exc.BadRequest(resource='router', msg=msg)
            self._validate_port_in_range_or_admin(context, subnets, port)
            return port, subnets

    def _notify_attaching_interface(self, context, router_db, port,
                                    interface_info):
        """Notify third party code that an interface is being attached to a
        router

        :param context: The context of the request.
        :param router_db: The router db object having an interface attached.
        :param port: The port object being attached to the router.
        :param interface_info: The requested interface attachment info passed
        to add_router_interface.
        :raises: RouterInterfaceAttachmentConflict if a third party code
        prevent the port to be attach to the router.
        """
        try:
            registry.notify(resources.ROUTER_INTERFACE,
                            events.BEFORE_CREATE,
                            self,
                            context=context,
                            router_db=router_db,
                            port=port,
                            interface_info=interface_info,
                            router_id=router_db.id,
                            network_id=port['network_id'])
        except exceptions.CallbackFailure as e:
            # raise the underlying exception
            reason = (_('cannot perform router interface attachment '
                        'due to %(reason)s') % {'reason': e})
            raise l3_exc.RouterInterfaceAttachmentConflict(reason=reason)

    def _add_interface_by_port(self, context, router, port_id, owner):
        # Update owner before actual process in order to avoid the
        # case where a port might get attached to a router without the
        # owner successfully updating due to an unavailable backend.
        self._core_plugin.update_port(
            context, port_id, {'port': {'device_id': router.id,
                                        'device_owner': owner}})

        return self._validate_router_port_info(context, router, port_id)

    def _port_has_ipv6_address(self, port):
        for fixed_ip in port['fixed_ips']:
            if netaddr.IPNetwork(fixed_ip['ip_address']).version == 6:
                return True

    def _find_ipv6_router_port_by_network(self, context, router, net_id):
        router_dev_owner = self._get_device_owner(context, router)
        for port in router.attached_ports:
            p = port['port']
            if p['device_owner'] != router_dev_owner:
                # we don't want any special purpose internal ports
                continue
            if p['network_id'] == net_id and self._port_has_ipv6_address(p):
                return port

    def _add_interface_by_subnet(self, context, router, subnet_id, owner):
        subnet = self._core_plugin.get_subnet(context, subnet_id)
        if not subnet['gateway_ip']:
            msg = _('Subnet for router interface must have a gateway IP')
            raise n_exc.BadRequest(resource='router', msg=msg)
        if subnet['project_id'] != context.project_id and not context.is_admin:
            msg = (_('Cannot add interface to router because subnet %s is not '
                     'owned by project making the request') % subnet_id)
            raise n_exc.BadRequest(resource='router', msg=msg)
        if (subnet['ip_version'] == 6 and subnet['ipv6_ra_mode'] is None
                and subnet['ipv6_address_mode'] is not None):
            msg = (_('IPv6 subnet %s configured to receive RAs from an '
                   'external router cannot be added to Neutron Router.') %
                   subnet['id'])
            raise n_exc.BadRequest(resource='router', msg=msg)
        self._check_for_dup_router_subnets(context, router,
                                           subnet['network_id'], [subnet])
        fixed_ip = {'ip_address': subnet['gateway_ip'],
                    'subnet_id': subnet['id']}

        if (subnet['ip_version'] == 6 and not
            ipv6_utils.is_ipv6_pd_enabled(subnet)):
            # Add new prefix to an existing ipv6 port with the same network id
            # if one exists
            port = self._find_ipv6_router_port_by_network(context, router,
                                                          subnet['network_id'])
            if port:
                fixed_ips = list(map(dict, port['port']['fixed_ips']))
                fixed_ips.append(fixed_ip)
                return self._core_plugin.update_port(context,
                        port['port_id'], {'port':
                            {'fixed_ips': fixed_ips}}), [subnet], False

        port_data = {'tenant_id': router.tenant_id,
                     'network_id': subnet['network_id'],
                     'fixed_ips': [fixed_ip],
                     'admin_state_up': True,
                     'device_id': router.id,
                     'device_owner': owner,
                     'name': ''}
        return p_utils.create_port(self._core_plugin, context,
                                   {'port': port_data}), [subnet], True

    @staticmethod
    def _make_router_interface_info(
            router_id, tenant_id, port_id, network_id, subnet_id, subnet_ids):
        return {
            'id': router_id,
            'tenant_id': tenant_id,
            'port_id': port_id,
            'network_id': network_id,
            'subnet_id': subnet_id,  # deprecated by IPv6 multi-prefix
            'subnet_ids': subnet_ids
        }

    @db_api.retry_if_session_inactive()
    def add_router_interface(self, context, router_id, interface_info=None):
        router = self._get_router(context, router_id)
        add_by_port, add_by_sub = self._validate_interface_info(interface_info)
        device_owner = self._get_device_owner(context, router_id)

        # This should be True unless adding an IPv6 prefix to an existing port
        new_router_intf = True
        cleanup_port = False

        if add_by_port:
            port_id = interface_info['port_id']
            port = self._check_router_port(context, port_id, '')
            revert_value = {'device_id': '',
                            'device_owner': port['device_owner']}
            with p_utils.update_port_on_error(
                    self._core_plugin, context, port_id, revert_value):
                port, subnets = self._add_interface_by_port(
                    context, router, port_id, device_owner)
        # add_by_subnet is not used here, because the validation logic of
        # _validate_interface_info ensures that either of add_by_* is True.
        else:
            port, subnets, new_router_intf = self._add_interface_by_subnet(
                    context, router, interface_info['subnet_id'], device_owner)
            cleanup_port = new_router_intf  # only cleanup port we created
            revert_value = {'device_id': '',
                            'device_owner': port['device_owner']}

        if cleanup_port:
            mgr = p_utils.delete_port_on_error(
                self._core_plugin, context, port['id'])
        else:
            mgr = p_utils.update_port_on_error(
                self._core_plugin, context, port['id'], revert_value)

        if new_router_intf:
            with mgr:
                self._notify_attaching_interface(context, router_db=router,
                                                 port=port,
                                                 interface_info=interface_info)
                self._add_router_port(
                    context, port['id'], router.id, device_owner)

        gw_ips = []
        gw_network_id = None
        if router.gw_port:
            gw_network_id = router.gw_port.network_id
            gw_ips = [x['ip_address'] for x in router.gw_port.fixed_ips]

        registry.notify(resources.ROUTER_INTERFACE,
                        events.AFTER_CREATE,
                        self,
                        context=context,
                        network_id=gw_network_id,
                        gateway_ips=gw_ips,
                        cidrs=[x['cidr'] for x in subnets],
                        subnets=subnets,
                        port_id=port['id'],
                        router_id=router_id,
                        port=port,
                        new_interface=new_router_intf,
                        interface_info=interface_info)

        with context.session.begin(subtransactions=True):
            context.session.refresh(router)
        return self._make_router_interface_info(
            router.id, port['tenant_id'], port['id'], port['network_id'],
            subnets[-1]['id'], [subnet['id'] for subnet in subnets])

    @db_api.retry_if_session_inactive()
    def _add_router_port(self, context, port_id, router_id, device_owner):
        l3_obj.RouterPort(
            context,
            port_id=port_id,
            router_id=router_id,
            port_type=device_owner
        ).create()
        # Update owner after actual process again in order to
        # make sure the records in routerports table and ports
        # table are consistent.
        self._core_plugin.update_port(
            context, port_id, {'port': {'device_id': router_id,
                                        'device_owner': device_owner}})

    def _confirm_router_interface_not_in_use(self, context, router_id,
                                             subnet_id):
        subnet = self._core_plugin.get_subnet(context, subnet_id)
        subnet_cidr = netaddr.IPNetwork(subnet['cidr'])
        try:
            kwargs = {'context': context, 'router_id': router_id,
                      'subnet_id': subnet_id}
            registry.notify(
                resources.ROUTER_INTERFACE,
                events.BEFORE_DELETE, self, **kwargs)
        except exceptions.CallbackFailure as e:
            # NOTE(armax): preserve old check's behavior
            if len(e.errors) == 1:
                raise e.errors[0].error
            raise l3_exc.RouterInUse(router_id=router_id, reason=e)
        fip_objs = l3_obj.FloatingIP.get_objects(context, router_id=router_id)
        for fip_obj in fip_objs:
            if fip_obj.fixed_ip_address in subnet_cidr:
                raise l3_exc.RouterInterfaceInUseByFloatingIP(
                    router_id=router_id, subnet_id=subnet_id)

    def _remove_interface_by_port(self, context, router_id,
                                  port_id, subnet_id, owner):
        obj = l3_obj.RouterPort.get_object(
            context,
            port_id=port_id,
            router_id=router_id,
            port_type=owner
        )
        if obj:
            try:
                port = self._core_plugin.get_port(context, obj.port_id)
            except n_exc.PortNotFound:
                raise l3_exc.RouterInterfaceNotFound(
                    router_id=router_id, port_id=port_id)
        else:
            raise l3_exc.RouterInterfaceNotFound(
                router_id=router_id, port_id=port_id)
        port_subnet_ids = [fixed_ip['subnet_id']
                           for fixed_ip in port['fixed_ips']]
        if subnet_id and subnet_id not in port_subnet_ids:
            raise n_exc.SubnetMismatchForPort(
                port_id=port_id, subnet_id=subnet_id)
        subnets = [self._core_plugin.get_subnet(context, port_subnet_id)
                   for port_subnet_id in port_subnet_ids]
        for port_subnet_id in port_subnet_ids:
            self._confirm_router_interface_not_in_use(
                    context, router_id, port_subnet_id)
        self._core_plugin.delete_port(context, port['id'],
                                      l3_port_check=False)
        return (port, subnets)

    def _remove_interface_by_subnet(self, context,
                                    router_id, subnet_id, owner):
        self._confirm_router_interface_not_in_use(
            context, router_id, subnet_id)
        subnet = self._core_plugin.get_subnet(context, subnet_id)

        try:
            ports = port_obj.Port.get_ports_by_router(
                context, router_id, owner, subnet)

            for p in ports:
                try:
                    p = self._core_plugin.get_port(context, p.id)
                except n_exc.PortNotFound:
                    continue
                port_subnets = [fip['subnet_id'] for fip in p['fixed_ips']]
                if subnet_id in port_subnets and len(port_subnets) > 1:
                    # multiple prefix port - delete prefix from port
                    fixed_ips = [dict(fip) for fip in p['fixed_ips']
                                 if fip['subnet_id'] != subnet_id]
                    self._core_plugin.update_port(context, p['id'],
                            {'port':
                                {'fixed_ips': fixed_ips}})
                    return (p, [subnet])
                elif subnet_id in port_subnets:
                    # only one subnet on port - delete the port
                    self._core_plugin.delete_port(context, p['id'],
                                                  l3_port_check=False)
                    return (p, [subnet])
        except exc.NoResultFound:
            pass
        raise l3_exc.RouterInterfaceNotFoundForSubnet(
            router_id=router_id, subnet_id=subnet_id)

    @db_api.retry_if_session_inactive()
    def remove_router_interface(self, context, router_id, interface_info):
        remove_by_port, remove_by_subnet = (
            self._validate_interface_info(interface_info, for_removal=True)
        )
        port_id = interface_info.get('port_id')
        subnet_id = interface_info.get('subnet_id')
        device_owner = self._get_device_owner(context, router_id)
        if remove_by_port:
            port, subnets = self._remove_interface_by_port(context, router_id,
                                                           port_id, subnet_id,
                                                           device_owner)
        # remove_by_subnet is not used here, because the validation logic of
        # _validate_interface_info ensures that at least one of remote_by_*
        # is True.
        else:
            port, subnets = self._remove_interface_by_subnet(
                    context, router_id, subnet_id, device_owner)

        gw_network_id = None
        gw_ips = []
        router = self._get_router(context, router_id)
        if router.gw_port:
            gw_network_id = router.gw_port.network_id
            gw_ips = [x['ip_address'] for x in router.gw_port.fixed_ips]

        registry.notify(resources.ROUTER_INTERFACE,
                        events.AFTER_DELETE,
                        self,
                        context=context,
                        cidrs=[x['cidr'] for x in subnets],
                        network_id=gw_network_id,
                        gateway_ips=gw_ips,
                        port=port,
                        router_id=router_id,
                        interface_info=interface_info)
        with context.session.begin(subtransactions=True):
            context.session.refresh(router)
        return self._make_router_interface_info(router_id, port['tenant_id'],
                                                port['id'], port['network_id'],
                                                subnets[0]['id'],
                                                [subnet['id'] for subnet in
                                                    subnets])

    def _get_floatingip(self, context, id):
        floatingip = l3_obj.FloatingIP.get_object(context, id=id)
        if not floatingip:
            raise l3_exc.FloatingIPNotFound(floatingip_id=id)
        return floatingip

    def _make_floatingip_dict(self, floatingip, fields=None,
                              process_extensions=True):
        floating_ip_address = (str(floatingip.floating_ip_address)
            if floatingip.floating_ip_address else None)
        fixed_ip_address = (str(floatingip.fixed_ip_address)
            if floatingip.fixed_ip_address else None)
        res = {'id': floatingip.id,
               'tenant_id': floatingip.project_id,
               'floating_ip_address': floating_ip_address,
               'floating_network_id': floatingip.floating_network_id,
               'router_id': floatingip.router_id,
               'port_id': floatingip.fixed_port_id,
               'fixed_ip_address': fixed_ip_address,
               'status': floatingip.status}
        # NOTE(mlavalle): The following assumes this mixin is used in a
        # class inheriting from CommonDbMixin, which is true for all existing
        # plugins.
        # TODO(lujinluo): Change floatingip.db_obj to floatingip once all
        # codes are migrated to use Floating IP OVO object.
        if process_extensions:
            resource_extend.apply_funcs(
                l3_apidef.FLOATINGIPS, res, floatingip.db_obj)
        return db_utils.resource_fields(res, fields)

    def _get_router_for_floatingip(self, context, internal_port,
                                   internal_subnet_id,
                                   external_network_id):
        subnet = self._core_plugin.get_subnet(context, internal_subnet_id)
        return self.get_router_for_floatingip(context,
            internal_port, subnet, external_network_id)

    # NOTE(yamamoto): This method is an override point for plugins
    # inheriting this class.  Do not optimize this out.
    def get_router_for_floatingip(self, context, internal_port,
                                  internal_subnet, external_network_id):
        """Find a router to handle the floating-ip association.

        :param internal_port: The port for the fixed-ip.
        :param internal_subnet: The subnet for the fixed-ip.
        :param external_network_id: The external network for floating-ip.

        :raises: ExternalGatewayForFloatingIPNotFound if no suitable router
        is found.
        """

        # Find routers(with router_id and interface address) that
        # connect given internal subnet and the external network.
        # Among them, if the router's interface address matches
        # with subnet's gateway-ip, return that router.
        # Otherwise return the first router.
        RouterPort = l3_models.RouterPort
        gw_port = orm.aliased(models_v2.Port, name="gw_port")
        # TODO(lujinluo): Need IPAllocation and Port object
        routerport_qry = context.session.query(
            RouterPort.router_id, models_v2.IPAllocation.ip_address).join(
            models_v2.Port, models_v2.IPAllocation).filter(
            models_v2.Port.network_id == internal_port['network_id'],
            RouterPort.port_type.in_(constants.ROUTER_INTERFACE_OWNERS),
            models_v2.IPAllocation.subnet_id == internal_subnet['id']
        ).join(gw_port, gw_port.device_id == RouterPort.router_id).filter(
            gw_port.network_id == external_network_id,
            gw_port.device_owner == DEVICE_OWNER_ROUTER_GW
        ).distinct()

        first_router_id = None
        for router_id, interface_ip in routerport_qry:
            if interface_ip == internal_subnet['gateway_ip']:
                return router_id
            if not first_router_id:
                first_router_id = router_id
        if first_router_id:
            return first_router_id

        raise l3_exc.ExternalGatewayForFloatingIPNotFound(
            subnet_id=internal_subnet['id'],
            external_network_id=external_network_id,
            port_id=internal_port['id'])

    def _port_ipv4_fixed_ips(self, port):
        return [ip for ip in port['fixed_ips']
                if netaddr.IPAddress(ip['ip_address']).version == 4]

    def _internal_fip_assoc_data(self, context, fip, tenant_id):
        """Retrieve internal port data for floating IP.

        Retrieve information concerning the internal port where
        the floating IP should be associated to.
        """
        internal_port = self._core_plugin.get_port(context, fip['port_id'])
        if internal_port['tenant_id'] != tenant_id and not context.is_admin:
            port_id = fip['port_id']
            msg = (_('Cannot process floating IP association with '
                     'Port %s, since that port is owned by a '
                     'different tenant') % port_id)
            raise n_exc.BadRequest(resource='floatingip', msg=msg)

        internal_subnet_id = None
        if not utils.is_fip_serviced(internal_port.get('device_owner')):
            msg = _('Port %(id)s is unable to be assigned a floating IP')
            raise n_exc.BadRequest(resource='floatingip', msg=msg)
        if fip.get('fixed_ip_address'):
            internal_ip_address = fip['fixed_ip_address']
            if netaddr.IPAddress(internal_ip_address).version != 4:
                msg = (_('Cannot process floating IP association with %s, '
                         'since that is not an IPv4 address') %
                       internal_ip_address)
                raise n_exc.BadRequest(resource='floatingip', msg=msg)
            for ip in internal_port['fixed_ips']:
                if ip['ip_address'] == internal_ip_address:
                    internal_subnet_id = ip['subnet_id']
            if not internal_subnet_id:
                msg = (_('Port %(id)s does not have fixed ip %(address)s') %
                       {'id': internal_port['id'],
                        'address': internal_ip_address})
                raise n_exc.BadRequest(resource='floatingip', msg=msg)
        else:
            ipv4_fixed_ips = self._port_ipv4_fixed_ips(internal_port)
            if not ipv4_fixed_ips:
                msg = (_('Cannot add floating IP to port %s that has '
                         'no fixed IPv4 addresses') % internal_port['id'])
                raise n_exc.BadRequest(resource='floatingip', msg=msg)
            if len(ipv4_fixed_ips) > 1:
                msg = (_('Port %s has multiple fixed IPv4 addresses.  Must '
                         'provide a specific IPv4 address when assigning a '
                         'floating IP') % internal_port['id'])
                raise n_exc.BadRequest(resource='floatingip', msg=msg)
            internal_ip_address = ipv4_fixed_ips[0]['ip_address']
            internal_subnet_id = ipv4_fixed_ips[0]['subnet_id']
        return internal_port, internal_subnet_id, internal_ip_address

    def _get_assoc_data(self, context, fip, floatingip_obj):
        """Determine/extract data associated with the internal port.

        When a floating IP is associated with an internal port,
        we need to extract/determine some data associated with the
        internal port, including the internal_ip_address, and router_id.
        The confirmation of the internal port whether owned by the tenant who
        owns the floating IP will be confirmed by _get_router_for_floatingip.
        """
        (internal_port, internal_subnet_id,
         internal_ip_address) = self._internal_fip_assoc_data(
            context, fip, floatingip_obj.project_id)
        router_id = self._get_router_for_floatingip(
            context, internal_port,
            internal_subnet_id, floatingip_obj.floating_network_id)

        if self.is_router_distributed(context, router_id):
            if not can_port_be_bound_to_virtual_bridge(internal_port):
                msg = _('Port VNIC type is not valid to associate a FIP in '
                        'DVR mode')
                raise n_exc.BadRequest(resource='floatingip', msg=msg)

        return (fip['port_id'], internal_ip_address, router_id)

    def _check_and_get_fip_assoc(self, context, fip, floatingip_obj):
        port_id = internal_ip_address = router_id = None
        if fip.get('fixed_ip_address') and not fip.get('port_id'):
            msg = _("fixed_ip_address cannot be specified without a port_id")
            raise n_exc.BadRequest(resource='floatingip', msg=msg)
        if fip.get('port_id'):
            port_id, internal_ip_address, router_id = self._get_assoc_data(
                context,
                fip,
                floatingip_obj)

            if port_id == floatingip_obj.fixed_port_id:
                # Floating IP association is not changed.
                return port_id, internal_ip_address, router_id

            fip_exists = l3_obj.FloatingIP.objects_exist(
                    context,
                    fixed_port_id=fip['port_id'],
                    floating_network_id=floatingip_obj.floating_network_id,
                    fixed_ip_address=netaddr.IPAddress(internal_ip_address))
            if fip_exists:
                floating_ip_address = (str(floatingip_obj.floating_ip_address)
                    if floatingip_obj.floating_ip_address else None)
                raise l3_exc.FloatingIPPortAlreadyAssociated(
                    port_id=fip['port_id'],
                    fip_id=floatingip_obj.id,
                    floating_ip_address=floating_ip_address,
                    fixed_ip=internal_ip_address,
                    net_id=floatingip_obj.floating_network_id)

        if fip and 'port_id' not in fip and floatingip_obj.fixed_port_id:
            # NOTE(liuyulong): without the fix of bug #1610045 here could
            # also let floating IP can be dissociated with an empty
            # updating dict.
            fip['port_id'] = floatingip_obj.fixed_port_id
            port_id, internal_ip_address, router_id = self._get_assoc_data(
                context, fip, floatingip_obj)

        # After all upper conditions, if updating API dict is submitted with
        # {'port_id': null}, then the floating IP cloud also be dissociated.
        return port_id, internal_ip_address, router_id

    def _update_fip_assoc(self, context, fip, floatingip_obj, external_port):
        previous_router_id = floatingip_obj.router_id
        port_id, internal_ip_address, router_id = (
            self._check_and_get_fip_assoc(context, fip, floatingip_obj))
        floatingip_obj.fixed_ip_address = (
            netaddr.IPAddress(internal_ip_address)
            if internal_ip_address else None)
        floatingip_obj.fixed_port_id = port_id
        floatingip_obj.router_id = router_id
        floatingip_obj.last_known_router_id = previous_router_id
        if 'description' in fip:
            floatingip_obj.description = fip['description']
        floating_ip_address = (str(floatingip_obj.floating_ip_address)
            if floatingip_obj.floating_ip_address else None)
        return {'fixed_ip_address': internal_ip_address,
                'fixed_port_id': port_id,
                'router_id': router_id,
                'last_known_router_id': previous_router_id,
                'floating_ip_address': floating_ip_address,
                'floating_network_id': floatingip_obj.floating_network_id,
                'floating_ip_id': floatingip_obj.id,
                'context': context}

    def _is_ipv4_network(self, context, net_id):
        net = self._core_plugin._get_network(context, net_id)
        return any(s.ip_version == 4 for s in net.subnets)

    def _create_floatingip(self, context, floatingip,
            initial_status=constants.FLOATINGIP_STATUS_ACTIVE):
        fip = floatingip['floatingip']
        fip_id = uuidutils.generate_uuid()

        f_net_id = fip['floating_network_id']
        if not self._core_plugin._network_is_external(context, f_net_id):
            msg = _("Network %s is not a valid external network") % f_net_id
            raise n_exc.BadRequest(resource='floatingip', msg=msg)

        if not self._is_ipv4_network(context, f_net_id):
            msg = _("Network %s does not contain any IPv4 subnet") % f_net_id
            raise n_exc.BadRequest(resource='floatingip', msg=msg)

        # This external port is never exposed to the tenant.
        # it is used purely for internal system and admin use when
        # managing floating IPs.

        port = {'tenant_id': '',  # tenant intentionally not set
                'network_id': f_net_id,
                'admin_state_up': True,
                'device_id': 'PENDING',
                'device_owner': DEVICE_OWNER_FLOATINGIP,
                'status': constants.PORT_STATUS_NOTAPPLICABLE,
                'name': ''}

        # Both subnet_id and floating_ip_address are accepted, if
        # floating_ip_address is not in the subnet,
        # InvalidIpForSubnet exception will be raised.
        fixed_ip = {}
        if validators.is_attr_set(fip.get('subnet_id')):
            fixed_ip['subnet_id'] = fip['subnet_id']
        if validators.is_attr_set(fip.get('floating_ip_address')):
            fixed_ip['ip_address'] = fip['floating_ip_address']
        if fixed_ip:
            port['fixed_ips'] = [fixed_ip]

        # 'status' in port dict could not be updated by default, use
        # check_allow_post to stop the verification of system
        external_port = p_utils.create_port(self._core_plugin,
                                            context.elevated(),
                                            {'port': port},
                                            check_allow_post=False)

        with p_utils.delete_port_on_error(self._core_plugin,
                                          context.elevated(),
                                          external_port['id']),\
                context.session.begin(subtransactions=True):
            # Ensure IPv4 addresses are allocated on external port
            external_ipv4_ips = self._port_ipv4_fixed_ips(external_port)
            if not external_ipv4_ips:
                raise n_exc.ExternalIpAddressExhausted(net_id=f_net_id)

            floating_fixed_ip = external_ipv4_ips[0]
            floating_ip_address = floating_fixed_ip['ip_address']
            floatingip_obj = l3_obj.FloatingIP(
                context,
                id=fip_id,
                project_id=fip['tenant_id'],
                status=initial_status,
                floating_network_id=fip['floating_network_id'],
                floating_ip_address=floating_ip_address,
                floating_port_id=external_port['id'],
                description=fip.get('description'))
            # Update association with internal port
            # and define external IP address
            assoc_result = self._update_fip_assoc(
                context, fip, floatingip_obj, external_port)
            floatingip_obj.create()
            floatingip_dict = self._make_floatingip_dict(
                floatingip_obj, process_extensions=False)
            if self._is_dns_integration_supported:
                dns_data = self._process_dns_floatingip_create_precommit(
                    context, floatingip_dict, fip)
            if self._is_fip_qos_supported:
                self._process_extra_fip_qos_create(context, fip_id, fip)
            floatingip_obj = l3_obj.FloatingIP.get_object(
                context, id=floatingip_obj.id)
            floatingip_db = floatingip_obj.db_obj

            registry.notify(resources.FLOATING_IP, events.PRECOMMIT_CREATE,
                            self, context=context, floatingip=fip,
                            floatingip_id=fip_id,
                            floatingip_db=floatingip_db)

        self._core_plugin.update_port(context.elevated(), external_port['id'],
                                      {'port': {'device_id': fip_id}})
        registry.notify(resources.FLOATING_IP,
                        events.AFTER_UPDATE,
                        self._update_fip_assoc,
                        **assoc_result)

        if self._is_dns_integration_supported:
            self._process_dns_floatingip_create_postcommit(context,
                                                           floatingip_dict,
                                                           dns_data)
        # TODO(lujinluo): Change floatingip_db to floatingip_obj once all
        # codes are migrated to use Floating IP OVO object.
        resource_extend.apply_funcs(l3_apidef.FLOATINGIPS, floatingip_dict,
                                    floatingip_db)
        return floatingip_dict

    @db_api.retry_if_session_inactive()
    def create_floatingip(self, context, floatingip,
            initial_status=constants.FLOATINGIP_STATUS_ACTIVE):
        return self._create_floatingip(context, floatingip, initial_status)

    def _update_floatingip(self, context, id, floatingip):
        fip = floatingip['floatingip']
        with context.session.begin(subtransactions=True):
            floatingip_obj = self._get_floatingip(context, id)
            old_floatingip = self._make_floatingip_dict(floatingip_obj)
            fip_port_id = floatingip_obj.floating_port_id
            assoc_result = self._update_fip_assoc(
                context, fip, floatingip_obj,
                self._core_plugin.get_port(context.elevated(), fip_port_id))
            floatingip_obj.update()
            floatingip_dict = self._make_floatingip_dict(floatingip_obj)
            if self._is_dns_integration_supported:
                dns_data = self._process_dns_floatingip_update_precommit(
                    context, floatingip_dict)
            if self._is_fip_qos_supported:
                self._process_extra_fip_qos_update(context,
                                                   floatingip_obj,
                                                   fip,
                                                   old_floatingip)
            floatingip_obj = l3_obj.FloatingIP.get_object(
                context, id=floatingip_obj.id)
            floatingip_db = floatingip_obj.db_obj
            registry.notify(resources.FLOATING_IP,
                            events.PRECOMMIT_UPDATE,
                            self,
                            floatingip=floatingip,
                            floatingip_db=floatingip_db,
                            old_floatingip=old_floatingip,
                            **assoc_result)

        registry.notify(resources.FLOATING_IP,
                        events.AFTER_UPDATE,
                        self._update_fip_assoc,
                        **assoc_result)

        if self._is_dns_integration_supported:
            self._process_dns_floatingip_update_postcommit(context,
                                                           floatingip_dict,
                                                           dns_data)
        # TODO(lujinluo): Change floatingip_db to floatingip_obj once all
        # codes are migrated to use Floating IP OVO object.
        resource_extend.apply_funcs(l3_apidef.FLOATINGIPS, floatingip_dict,
                                    floatingip_db)
        return old_floatingip, floatingip_dict

    def _floatingips_to_router_ids(self, floatingips):
        return list(set([floatingip['router_id']
                         for floatingip in floatingips
                         if floatingip['router_id']]))

    @db_api.retry_if_session_inactive()
    def update_floatingip(self, context, id, floatingip):
        _old_floatingip, floatingip = self._update_floatingip(
            context, id, floatingip)
        return floatingip

    @db_api.retry_if_session_inactive()
    def update_floatingip_status(self, context, floatingip_id, status):
        """Update operational status for floating IP in neutron DB."""
        return l3_obj.FloatingIP.update_object(
            context, {'status': status}, id=floatingip_id)

    @registry.receives(resources.PORT, [events.PRECOMMIT_DELETE])
    def _precommit_delete_port_callback(
            self, resource, event, trigger, **kwargs):
        if (kwargs['port']['device_owner'] ==
                constants.DEVICE_OWNER_FLOATINGIP):
            registry.notify(resources.FLOATING_IP, events.PRECOMMIT_DELETE,
                            self, **kwargs)

    def _delete_floatingip(self, context, id):
        floatingip = self._get_floatingip(context, id)
        floatingip_dict = self._make_floatingip_dict(floatingip)
        if self._is_dns_integration_supported:
            self._process_dns_floatingip_delete(context, floatingip_dict)
        # Foreign key cascade will take care of the removal of the
        # floating IP record once the port is deleted. We can't start
        # a transaction first to remove it ourselves because the delete_port
        # method will yield in its post-commit activities.
        self._core_plugin.delete_port(context.elevated(),
                                      floatingip.floating_port_id,
                                      l3_port_check=False)
        registry.notify(resources.FLOATING_IP, events.AFTER_DELETE,
                        self, **floatingip_dict)
        return floatingip_dict

    @db_api.retry_if_session_inactive()
    def delete_floatingip(self, context, id):
        self._delete_floatingip(context, id)

    @db_api.retry_if_session_inactive()
    def get_floatingip(self, context, id, fields=None):
        floatingip = self._get_floatingip(context, id)
        return self._make_floatingip_dict(floatingip, fields)

    @db_api.retry_if_session_inactive()
    def get_floatingips(self, context, filters=None, fields=None,
                        sorts=None, limit=None, marker=None,
                        page_reverse=False):
        pager = base_obj.Pager(sorts, limit, page_reverse, marker)
        filters = filters or {}
        for key, val in API_TO_DB_COLUMN_MAP.items():
            if key in filters:
                filters[val] = filters.pop(key)
        floatingip_objs = l3_obj.FloatingIP.get_objects(
            context, _pager=pager, validate_filters=False, **filters)
        floatingip_dicts = [
            self._make_floatingip_dict(floatingip_obj, fields)
            for floatingip_obj in floatingip_objs
        ]
        return floatingip_dicts

    @db_api.retry_if_session_inactive()
    def delete_disassociated_floatingips(self, context, network_id):
        fip_objs = l3_obj.FloatingIP.get_objects(
            context,
            floating_network_id=network_id, router_id=None, fixed_port_id=None)

        for fip in fip_objs:
            self.delete_floatingip(context, fip.id)

    @db_api.retry_if_session_inactive()
    def get_floatingips_count(self, context, filters=None):
        filters = filters or {}
        return l3_obj.FloatingIP.count(context, **filters)

    def _router_exists(self, context, router_id):
        try:
            self.get_router(context.elevated(), router_id)
            return True
        except l3_exc.RouterNotFound:
            return False

    def prevent_l3_port_deletion(self, context, port_id):
        """Checks to make sure a port is allowed to be deleted.

        Raises an exception if this is not the case.  This should be called by
        any plugin when the API requests the deletion of a port, since some
        ports for L3 are not intended to be deleted directly via a DELETE
        to /ports, but rather via other API calls that perform the proper
        deletion checks.
        """
        try:
            port = self._core_plugin.get_port(context, port_id)
        except n_exc.PortNotFound:
            # non-existent ports don't need to be protected from deletion
            return
        if port['device_owner'] not in self.router_device_owners:
            return
        # Raise port in use only if the port has IP addresses
        # Otherwise it's a stale port that can be removed
        fixed_ips = port['fixed_ips']
        if not fixed_ips:
            LOG.debug("Port %(port_id)s has owner %(port_owner)s, but "
                      "no IP address, so it can be deleted",
                      {'port_id': port['id'],
                       'port_owner': port['device_owner']})
            return
        # NOTE(kevinbenton): we also check to make sure that the
        # router still exists. It's possible for HA router interfaces
        # to remain after the router is deleted if they encounter an
        # error during deletion.
        # Elevated context in case router is owned by another tenant
        if port['device_owner'] == DEVICE_OWNER_FLOATINGIP:
            if not l3_obj.FloatingIP.objects_exist(
                    context, id=port['device_id']):
                LOG.debug("Floating IP %(f_id)s corresponding to port "
                          "%(port_id)s no longer exists, allowing deletion.",
                          {'f_id': port['device_id'], 'port_id': port['id']})
                return
        elif not self._router_exists(context, port['device_id']):
            LOG.debug("Router %(router_id)s corresponding to port "
                      "%(port_id)s  no longer exists, allowing deletion.",
                      {'router_id': port['device_id'],
                       'port_id': port['id']})
            return

        reason = _('has device owner %s') % port['device_owner']
        raise n_exc.ServicePortInUse(port_id=port['id'],
                                     reason=reason)

    @db_api.retry_if_session_inactive()
    def disassociate_floatingips(self, context, port_id, do_notify=True):
        """Disassociate all floating IPs linked to specific port.

        @param port_id: ID of the port to disassociate floating IPs.
        @param do_notify: whether we should notify routers right away.
                          This parameter is ignored.
        @return: set of router-ids that require notification updates
        """
        with context.session.begin(subtransactions=True):
            floating_ip_objs = l3_obj.FloatingIP.get_objects(
                context, fixed_port_id=port_id)
            router_ids = {fip.router_id for fip in floating_ip_objs}
            old_fips = {fip.id: fip.to_dict() for fip in floating_ip_objs}
            values = {'fixed_port_id': None,
                      'fixed_ip_address': None,
                      'router_id': None}
            l3_obj.FloatingIP.update_objects(
                context, values, fixed_port_id=port_id)
            for fip in floating_ip_objs:
                registry.notify(resources.FLOATING_IP, events.PRECOMMIT_UPDATE,
                                self,
                                floatingip={l3_apidef.FLOATINGIP: values},
                                floatingip_db=fip,
                                old_floatingip=old_fips[fip.id],
                                router_ids=router_ids)

        for fip in floating_ip_objs:
            assoc_result = {
                'fixed_ip_address': None,
                'fixed_port_id': None,
                'router_id': None,
                'floating_ip_address': fip.floating_ip_address,
                'floating_network_id': fip.floating_network_id,
                'floating_ip_id': fip.id,
                'context': context,
                'router_ids': router_ids,
            }
            registry.notify(resources.FLOATING_IP, events.AFTER_UPDATE, self,
                            **assoc_result)
        return router_ids

    def _get_floatingips_by_port_id(self, context, port_id):
        """Helper function to retrieve the fips associated with a port_id."""
        return l3_obj.FloatingIP.get_objects(context, fixed_port_id=port_id)

    def _build_routers_list(self, context, routers, gw_ports):
        """Subclasses can override this to add extra gateway info"""
        return routers

    def _make_router_dict_with_gw_port(self, router, fields):
        result = self._make_router_dict(router, fields)
        if router.get('gw_port'):
            result['gw_port'] = self._core_plugin._make_port_dict(
                router['gw_port'])
        return result

    def _get_sync_routers(self, context, router_ids=None, active=None):
        """Query routers and their gw ports for l3 agent.

        Query routers with the router_ids. The gateway ports, if any,
        will be queried too.
        l3 agent has an option to deal with only one router id. In addition,
        when we need to notify the agent the data about only one router
        (when modification of router, its interfaces, gw_port and floatingips),
        we will have router_ids.
        @param router_ids: the list of router ids which we want to query.
                           if it is None, all of routers will be queried.
        @return: a list of dicted routers with dicted gw_port populated if any
        """
        filters = {'id': router_ids} if router_ids else {}
        if active is not None:
            filters['admin_state_up'] = [active]
        router_dicts = model_query.get_collection(
            context, l3_models.Router, self._make_router_dict_with_gw_port,
            filters=filters)
        if not router_dicts:
            return []
        gw_ports = dict((r['gw_port']['id'], r['gw_port'])
                        for r in router_dicts
                        if r.get('gw_port'))
        return self._build_routers_list(context, router_dicts, gw_ports)

    def _make_floatingip_dict_with_scope(self, floatingip_obj, scope_id):
        d = self._make_floatingip_dict(floatingip_obj)
        d['fixed_ip_address_scope'] = scope_id
        return d

    def _get_sync_floating_ips(self, context, router_ids):
        """Query floating_ips that relate to list of router_ids with scope.

        This is different than the regular get_floatingips in that it finds the
        address scope of the fixed IP.  The router needs to know this to
        distinguish it from other scopes.

        There are a few redirections to go through to discover the address
        scope from the floating ip.
        """
        if not router_ids:
            return []

        return [
            self._make_floatingip_dict_with_scope(*scoped_fip)
            for scoped_fip in l3_obj.FloatingIP.get_scoped_floating_ips(
                context, router_ids)
        ]

    def _get_sync_interfaces(self, context, router_ids, device_owners=None):
        """Query router interfaces that relate to list of router_ids."""
        device_owners = device_owners or [DEVICE_OWNER_ROUTER_INTF,
                                          DEVICE_OWNER_HA_REPLICATED_INT]
        if not router_ids:
            return []
        # TODO(lujinluo): Need Port as synthetic field
        objs = l3_obj.RouterPort.get_objects(
            context, router_id=router_ids, port_type=list(device_owners))

        interfaces = [self._core_plugin._make_port_dict(rp.db_obj.port)
                      for rp in objs]
        return interfaces

    @staticmethod
    def _each_port_having_fixed_ips(ports):
        for port in ports or []:
            fixed_ips = port.get('fixed_ips', [])
            if not fixed_ips:
                # Skip ports without IPs, which can occur if a subnet
                # attached to a router is deleted
                LOG.info("Skipping port %s as no IP is configure on "
                         "it",
                         port['id'])
                continue
            yield port

    def _get_subnets_by_network_list(self, context, network_ids):
        if not network_ids:
            return {}

        query = context.session.query(models_v2.Subnet,
                                      models_v2.SubnetPool.address_scope_id)
        query = query.outerjoin(
            models_v2.SubnetPool,
            models_v2.Subnet.subnetpool_id == models_v2.SubnetPool.id)
        query = query.filter(models_v2.Subnet.network_id.in_(network_ids))

        fields = ['id', 'cidr', 'gateway_ip', 'dns_nameservers',
                  'network_id', 'ipv6_ra_mode', 'subnetpool_id']

        def make_subnet_dict_with_scope(row):
            subnet_db, address_scope_id = row
            subnet = self._core_plugin._make_subnet_dict(
                subnet_db, fields, context=context)
            subnet['address_scope_id'] = address_scope_id
            return subnet

        subnets_by_network = dict((id, []) for id in network_ids)
        for subnet in (make_subnet_dict_with_scope(row) for row in query):
            subnets_by_network[subnet['network_id']].append(subnet)
        return subnets_by_network

    def _get_mtus_by_network_list(self, context, network_ids):
        if not network_ids:
            return {}
        filters = {'id': network_ids}
        fields = ['id', 'mtu']
        networks = self._core_plugin.get_networks(context, filters=filters,
                                                  fields=fields)
        mtus_by_network = dict((network['id'], network.get('mtu', 0))
                               for network in networks)
        return mtus_by_network

    def _populate_mtu_and_subnets_for_ports(self, context, ports):
        """Populate ports with subnets.

        These ports already have fixed_ips populated.
        """
        network_ids = [p['network_id']
                       for p in self._each_port_having_fixed_ips(ports)]

        mtus_by_network = self._get_mtus_by_network_list(context, network_ids)
        subnets_by_network = self._get_subnets_by_network_list(
            context, network_ids)

        for port in self._each_port_having_fixed_ips(ports):

            port['subnets'] = []
            port['extra_subnets'] = []
            port['address_scopes'] = {constants.IP_VERSION_4: None,
                                      constants.IP_VERSION_6: None}

            scopes = {}
            for subnet in subnets_by_network[port['network_id']]:
                scope = subnet['address_scope_id']
                cidr = netaddr.IPNetwork(subnet['cidr'])
                scopes[cidr.version] = scope

                # If this subnet is used by the port (has a matching entry
                # in the port's fixed_ips), then add this subnet to the
                # port's subnets list, and populate the fixed_ips entry
                # entry with the subnet's prefix length.
                subnet_info = {'id': subnet['id'],
                               'cidr': subnet['cidr'],
                               'gateway_ip': subnet['gateway_ip'],
                               'dns_nameservers': subnet['dns_nameservers'],
                               'ipv6_ra_mode': subnet['ipv6_ra_mode'],
                               'subnetpool_id': subnet['subnetpool_id']}
                for fixed_ip in port['fixed_ips']:
                    if fixed_ip['subnet_id'] == subnet['id']:
                        port['subnets'].append(subnet_info)
                        prefixlen = cidr.prefixlen
                        fixed_ip['prefixlen'] = prefixlen
                        break
                else:
                    # This subnet is not used by the port.
                    port['extra_subnets'].append(subnet_info)

            port['address_scopes'].update(scopes)
            port['mtu'] = mtus_by_network.get(port['network_id'], 0)

    def _process_floating_ips(self, context, routers_dict, floating_ips):
        for floating_ip in floating_ips:
            router = routers_dict.get(floating_ip['router_id'])
            if router:
                router_floatingips = router.get(constants.FLOATINGIP_KEY,
                                                [])
                router_floatingips.append(floating_ip)
                router[constants.FLOATINGIP_KEY] = router_floatingips

    def _process_interfaces(self, routers_dict, interfaces):
        for interface in interfaces:
            router = routers_dict.get(interface['device_id'])
            if router:
                router_interfaces = router.get(constants.INTERFACE_KEY, [])
                router_interfaces.append(interface)
                router[constants.INTERFACE_KEY] = router_interfaces

    def _get_router_info_list(self, context, router_ids=None, active=None,
                              device_owners=None):
        """Query routers and their related floating_ips, interfaces."""
        with context.session.begin(subtransactions=True):
            routers = self._get_sync_routers(context,
                                             router_ids=router_ids,
                                             active=active)
            router_ids = [router['id'] for router in routers]
            interfaces = self._get_sync_interfaces(
                context, router_ids, device_owners)
            floating_ips = self._get_sync_floating_ips(context, router_ids)
            return (routers, interfaces, floating_ips)

    def get_sync_data(self, context, router_ids=None, active=None):
        routers, interfaces, floating_ips = self._get_router_info_list(
            context, router_ids=router_ids, active=active)
        ports_to_populate = [router['gw_port'] for router in routers
                             if router.get('gw_port')] + interfaces
        self._populate_mtu_and_subnets_for_ports(context, ports_to_populate)
        routers_dict = dict((router['id'], router) for router in routers)
        self._process_floating_ips(context, routers_dict, floating_ips)
        self._process_interfaces(routers_dict, interfaces)
        return list(routers_dict.values())

    def is_router_distributed(self, context, router_id):
        """Returns if a router is distributed or not

        If DVR extension is not enabled, no router will be distributed. This
        function is overridden in L3_NAT_with_dvr_db_mixin in case the DVR
        extension is loaded.
        """
        return False


@registry.has_registry_receivers
class L3RpcNotifierMixin(object):
    """Mixin class to add rpc notifier attribute to db_base_plugin_v2."""

    @staticmethod
    @registry.receives(resources.PORT, [events.AFTER_DELETE])
    def _notify_routers_callback(resource, event, trigger, **kwargs):
        context = kwargs['context']
        router_ids = kwargs['router_ids']
        l3plugin = directory.get_plugin(plugin_constants.L3)
        if l3plugin:
            l3plugin.notify_routers_updated(context, router_ids)
        else:
            LOG.debug('%s not configured', plugin_constants.L3)

    @staticmethod
    @registry.receives(resources.SUBNET, [events.AFTER_UPDATE])
    def _notify_subnet_gateway_ip_update(resource, event, trigger, **kwargs):
        l3plugin = directory.get_plugin(plugin_constants.L3)
        if not l3plugin:
            return
        context = kwargs['context']
        orig = kwargs['original_subnet']
        updated = kwargs['subnet']
        if orig['gateway_ip'] == updated['gateway_ip']:
            return
        network_id = updated['network_id']
        subnet_id = updated['id']
        query = context.session.query(models_v2.Port.device_id).filter_by(
                    network_id=network_id,
                    device_owner=DEVICE_OWNER_ROUTER_GW)
        query = query.join(models_v2.Port.fixed_ips).filter(
                    models_v2.IPAllocation.subnet_id == subnet_id)
        router_ids = set(port.device_id for port in query)
        for router_id in router_ids:
            l3plugin.notify_router_updated(context, router_id)

    @staticmethod
    @registry.receives(resources.SUBNETPOOL_ADDRESS_SCOPE,
                       [events.AFTER_UPDATE])
    def _notify_subnetpool_address_scope_update(resource, event,
                                                trigger, **kwargs):
        context = kwargs['context']
        subnetpool_id = kwargs['subnetpool_id']

        router_ids = l3_obj.RouterPort.get_router_ids_by_subnetpool(
            context, subnetpool_id)

        l3plugin = directory.get_plugin(plugin_constants.L3)
        if l3plugin:
            l3plugin.notify_routers_updated(context, router_ids)
        else:
            LOG.debug('%s not configured', plugin_constants.L3)

    @property
    def l3_rpc_notifier(self):
        if not hasattr(self, '_l3_rpc_notifier'):
            self._l3_rpc_notifier = l3_rpc_agent_api.L3AgentNotifyAPI()
        return self._l3_rpc_notifier

    @l3_rpc_notifier.setter
    def l3_rpc_notifier(self, value):
        self._l3_rpc_notifier = value

    def notify_router_updated(self, context, router_id,
                              operation=None):
        if router_id:
            self.l3_rpc_notifier.routers_updated(
                context, [router_id], operation)

    def notify_routers_updated(self, context, router_ids,
                               operation=None, data=None):
        if router_ids:
            self.l3_rpc_notifier.routers_updated(
                context, router_ids, operation, data)

    def notify_router_deleted(self, context, router_id):
        self.l3_rpc_notifier.router_deleted(context, router_id)


class L3_NAT_db_mixin(L3_NAT_dbonly_mixin, L3RpcNotifierMixin):
    """Mixin class to add rpc notifier methods to db_base_plugin_v2."""

    def create_router(self, context, router):
        router_dict = super(L3_NAT_db_mixin, self).create_router(context,
                                                                 router)
        if router_dict.get('external_gateway_info'):
            self.notify_router_updated(context, router_dict['id'], None)
        return router_dict

    def update_router(self, context, id, router):
        router_dict = super(L3_NAT_db_mixin, self).update_router(context,
                                                                 id, router)
        self.notify_router_updated(context, router_dict['id'], None)
        return router_dict

    def delete_router(self, context, id):
        super(L3_NAT_db_mixin, self).delete_router(context, id)
        self.notify_router_deleted(context, id)

    def notify_router_interface_action(
            self, context, router_interface_info, action):
        l3_method = '%s_router_interface' % action
        super(L3_NAT_db_mixin, self).notify_routers_updated(
            context, [router_interface_info['id']], l3_method,
            {'subnet_id': router_interface_info['subnet_id']})

        mapping = {'add': 'create', 'remove': 'delete'}
        notifier = n_rpc.get_notifier('network')
        router_event = 'router.interface.%s' % mapping[action]
        notifier.info(context, router_event,
                      {'router_interface': router_interface_info})

    def add_router_interface(self, context, router_id, interface_info=None):
        router_interface_info = super(
            L3_NAT_db_mixin, self).add_router_interface(
                context, router_id, interface_info)
        self.notify_router_interface_action(
            context, router_interface_info, 'add')
        return router_interface_info

    def remove_router_interface(self, context, router_id, interface_info):
        router_interface_info = super(
            L3_NAT_db_mixin, self).remove_router_interface(
                context, router_id, interface_info)
        self.notify_router_interface_action(
            context, router_interface_info, 'remove')
        return router_interface_info

    def create_floatingip(self, context, floatingip,
            initial_status=constants.FLOATINGIP_STATUS_ACTIVE):
        floatingip_dict = super(L3_NAT_db_mixin, self).create_floatingip(
            context, floatingip, initial_status)
        router_id = floatingip_dict['router_id']
        self.notify_router_updated(context, router_id, 'create_floatingip')
        return floatingip_dict

    def update_floatingip(self, context, id, floatingip):
        old_floatingip, floatingip = self._update_floatingip(
            context, id, floatingip)
        router_ids = self._floatingips_to_router_ids(
            [old_floatingip, floatingip])
        super(L3_NAT_db_mixin, self).notify_routers_updated(
            context, router_ids, 'update_floatingip', {})
        return floatingip

    def delete_floatingip(self, context, id):
        floating_ip = self._delete_floatingip(context, id)
        self.notify_router_updated(context, floating_ip['router_id'],
                                   'delete_floatingip')

    def disassociate_floatingips(self, context, port_id, do_notify=True):
        """Disassociate all floating IPs linked to specific port.

        @param port_id: ID of the port to disassociate floating IPs.
        @param do_notify: whether we should notify routers right away.
        @return: set of router-ids that require notification updates
                 if do_notify is False, otherwise None.
        """
        router_ids = super(L3_NAT_db_mixin, self).disassociate_floatingips(
            context, port_id, do_notify)
        if do_notify:
            self.notify_routers_updated(context, router_ids)
            # since caller assumes that we handled notifications on its
            # behalf, return nothing
            return

        return router_ids

    def notify_routers_updated(self, context, router_ids):
        super(L3_NAT_db_mixin, self).notify_routers_updated(
            context, list(router_ids), 'disassociate_floatingips', {})

    def _migrate_router_ports(
        self, context, router_db, old_owner, new_owner):
        """Update the model to support the dvr case of a router."""
        for rp in router_db.attached_ports:
            if rp.port_type == old_owner:
                rp.port_type = new_owner
                rp.port.device_owner = new_owner
