Make dvr_vmarp_table_update call conditional to dvr extension

Without making this call conditional, every l3plugin that
integrates with the ML2 plugin will need to implement this
method and this must not be necessary.

Closes-bug: #1349638

Change-Id: Ie9ba3bad4152810f5bfa530be54be70139cebc0c

neutron/plugins/ml2/rpc.py

@@ -18,6 +18,7 @@
 from neutron.common import constants as q_const
 from neutron.common import rpc as n_rpc
 from neutron.common import topics
+from neutron.common import utils
 from neutron.db import dhcp_rpc_base
 from neutron.db import securitygroups_rpc_base as sg_db_rpc
 from neutron.extensions import portbindings
@@ -190,7 +191,9 @@ def update_device_up(self, rpc_context, **kwargs):
                                             host)
         l3plugin = manager.NeutronManager.get_service_plugins().get(
             service_constants.L3_ROUTER_NAT)
-        if l3plugin:
+        if (l3plugin and
+            utils.is_extension_supported(l3plugin,
+                                         q_const.L3_DISTRIBUTED_EXT_ALIAS)):
             l3plugin.dvr_vmarp_table_update(rpc_context, port_id, "add")
 
     def get_dvr_mac_address_by_host(self, rpc_context, **kwargs):

neutron/tests/unit/ml2/test_rpcapi.py

@@ -28,6 +28,42 @@
 from neutron.tests import base
 
 
+class RpcCallbacks(base.BaseTestCase):
+
+    def setUp(self):
+        super(RpcCallbacks, self).setUp()
+        self.callbacks = plugin_rpc.RpcCallbacks(mock.Mock(), mock.Mock())
+
+    def _test_update_device_up(self, extensions, kwargs):
+        with mock.patch.object(plugin_rpc.manager, 'NeutronManager') as mgr:
+            with mock.patch.object(self.callbacks, '_device_to_port_id'):
+                mock_l3plugin = mock.Mock()
+                mgr.get_service_plugins.return_value = {
+                    'L3_ROUTER_NAT': mock_l3plugin
+                }
+                type(mock_l3plugin).supported_extension_aliases = (
+                    mock.PropertyMock(return_value=extensions))
+                self.callbacks.update_device_up(mock.ANY, **kwargs)
+        return mock_l3plugin
+
+    def test_update_device_up_without_dvr(self):
+        kwargs = {
+            'agent_id': 'foo_agent',
+            'device': 'foo_device'
+        }
+        l3plugin = self._test_update_device_up(['router'], kwargs)
+        self.assertFalse(l3plugin.dvr_vmarp_table_update.call_count)
+
+    def test_update_device_up_with_dvr(self):
+        kwargs = {
+            'agent_id': 'foo_agent',
+            'device': 'foo_device'
+        }
+        l3plugin = self._test_update_device_up(['router', 'dvr'], kwargs)
+        l3plugin.dvr_vmarp_table_update.assert_called_once_with(
+            mock.ANY, mock.ANY, 'add')
+
+
 class RpcApiTestCase(base.BaseTestCase):
 
     def _test_rpc_api(self, rpcapi, topic, method, rpc_method, **kwargs):