Trigger router update only when gateway port IP changed

During the ha router state change event, the gateway port only
changed the L2 binding host. So l3 agent has the entire gateway
port information. It is not necessary to send a router_update
message to l3 agent again.

Depends-On: https://review.opendev.org/708825/
Closes-Bug: #1795127
Change-Id: Ia332421aff995f42e7a6e6e96b74be1338d54fe1
(cherry picked from commit 452b282412)

neutron/common/utils.py

@@ -799,3 +799,25 @@ def disable_extension_by_service_plugin(core_plugin, service_plugin):
         core_plugin.supported_extension_aliases.remove('filter-validation')
         LOG.info('Disable filter validation extension by service plugin '
                  '%s.', service_plugin.__class__.__name__)
+
+
+def get_port_fixed_ips_set(port):
+    return set([ip["ip_address"] for ip in port.get("fixed_ips", [])])
+
+
+def port_ip_changed(new_port, original_port):
+    if not new_port or not original_port:
+        return False
+
+    # Quantity is not same, so it is changed.
+    if (len(new_port.get("fixed_ips", [])) !=
+            len(original_port.get("fixed_ips", []))):
+        return True
+
+    # IPs can be placed in any order, so use python set to verify the
+    # fixed IP addresses.
+    if (get_port_fixed_ips_set(new_port) !=
+            get_port_fixed_ips_set(original_port)):
+        return True
+
+    return False

neutron/db/l3_dvrscheduler_db.py

@@ -527,6 +527,15 @@ def _notify_l3_agent_port_update(resource, event, trigger, **kwargs):
     new_port = kwargs.get('port')
     original_port = kwargs.get('original_port')
 
+    is_fixed_ips_changed = n_utils.port_ip_changed(new_port, original_port)
+
+    if (original_port['device_owner'] in
+            [n_const.DEVICE_OWNER_HA_REPLICATED_INT,
+             n_const.DEVICE_OWNER_ROUTER_SNAT,
+             n_const.DEVICE_OWNER_ROUTER_GW] and
+            not is_fixed_ips_changed):
+        return
+
     if new_port and original_port:
         l3plugin = directory.get_plugin(plugin_constants.L3)
         context = kwargs['context']
@@ -616,10 +625,6 @@ def _notify_l3_agent_port_update(resource, event, trigger, **kwargs):
                         l3plugin, context, original_port, address_pair)
                 return
 
-        is_fixed_ips_changed = (
-            'fixed_ips' in new_port and
-            'fixed_ips' in original_port and
-            new_port['fixed_ips'] != original_port['fixed_ips'])
         if kwargs.get('mac_address_updated') or is_fixed_ips_changed:
             l3plugin.update_arp_entry_for_dvr_service_port(
                 context, new_port)

neutron/tests/unit/scheduler/test_l3_agent_scheduler.py

@@ -1029,10 +1029,12 @@ class L3DvrSchedulerTestCase(L3SchedulerBaseMixin,
             'context': self.adminContext,
             'original_port': {
                 portbindings.HOST_ID: 'vm-host',
+                'device_owner': DEVICE_OWNER_COMPUTE,
                 'mac_address': '02:04:05:17:18:19'
             },
             'port': {
                 portbindings.HOST_ID: 'vm-host',
+                'device_owner': DEVICE_OWNER_COMPUTE,
                 'mac_address': '02:04:05:17:18:29'
             },
             'mac_address_updated': True
@@ -1047,6 +1049,55 @@ class L3DvrSchedulerTestCase(L3SchedulerBaseMixin,
                 self.adminContext, kwargs.get('port'))
         self.assertFalse(l3plugin.dvr_handle_new_service_port.called)
 
+    def test__notify_l3_agent_update_port_with_ip_update(self):
+        kwargs = {
+            'context': self.adminContext,
+            'original_port': {
+                portbindings.HOST_ID: 'vm-host',
+                'device_owner': constants.DEVICE_OWNER_ROUTER_GW,
+                'fixed_ips': [{'ip_address': '1.1.1.1'}],
+                'mac_address': '02:04:05:17:18:19'
+            },
+            'port': {
+                portbindings.HOST_ID: 'vm-host',
+                'device_owner': constants.DEVICE_OWNER_ROUTER_GW,
+                'fixed_ips': [{'ip_address': '2.2.2.2'}],
+                'mac_address': '02:04:05:17:18:19'
+            },
+            'mac_address_updated': False
+        }
+        l3plugin = mock.Mock()
+        directory.add_plugin(plugin_constants.L3, l3plugin)
+        l3_dvrscheduler_db._notify_l3_agent_port_update(
+            'port', 'after_update', mock.ANY, **kwargs)
+
+        l3plugin.update_arp_entry_for_dvr_service_port.\
+            assert_called_once_with(
+                self.adminContext, kwargs.get('port'))
+        self.assertFalse(l3plugin.dvr_handle_new_service_port.called)
+
+    def test__notify_l3_agent_update_port_without_ip_change(self):
+        kwargs = {
+            'context': self.adminContext,
+            'original_port': {
+                portbindings.HOST_ID: 'vm-host',
+                'device_owner': constants.DEVICE_OWNER_ROUTER_GW,
+                'fixed_ips': [{'ip_address': '1.1.1.1'}],
+            },
+            'port': {
+                portbindings.HOST_ID: 'vm-host',
+                'device_owner': constants.DEVICE_OWNER_ROUTER_GW,
+                'fixed_ips': [{'ip_address': '1.1.1.1'}],
+            },
+        }
+        l3plugin = mock.Mock()
+        directory.add_plugin(plugin_constants.L3, l3plugin)
+        l3_dvrscheduler_db._notify_l3_agent_port_update(
+            'port', 'after_update', mock.ANY, **kwargs)
+
+        self.assertFalse(l3plugin.update_arp_entry_for_dvr_service_port.called)
+        self.assertFalse(l3plugin.dvr_handle_new_service_port.called)
+
     def test__notify_l3_agent_port_binding_change(self):
         self._test__notify_l3_agent_port_binding_change()