OFAgent: Fixing lost vlan ids on interfaces

Port the following patch to OFAgent.
commit: 60cb091171
https://review.openstack.org/#/c/66375/

Closes-Bug: #1309286

Change-Id: I04f99ef7928cd07959b29eb64b5744df397979b8

neutron/plugins/ofagent/agent/ofa_neutron_agent.py

@@ -956,6 +956,9 @@ class OFANeutronAgent(sg_rpc.SecurityGroupAgentRpcCallbackMixin):
         cur_ports = self.int_br.get_vif_port_set()
         self.int_br_device_count = len(cur_ports)
         port_info = {'current': cur_ports}
+        if updated_ports is None:
+            updated_ports = set()
+        updated_ports.update(self._find_lost_vlan_port(registered_ports))
         if updated_ports:
             # Some updated ports might have been removed in the
             # meanwhile, and therefore should not be processed.
@@ -974,6 +977,30 @@ class OFANeutronAgent(sg_rpc.SecurityGroupAgentRpcCallbackMixin):
         port_info['removed'] = registered_ports - cur_ports
         return port_info
 
+    def _find_lost_vlan_port(self, registered_ports):
+        """Return ports which have lost their vlan tag.
+
+        The returned value is a set of port ids of the ports concerned by a
+        vlan tag loss.
+        """
+        port_tags = self.int_br.get_port_tag_dict()
+        changed_ports = set()
+        for lvm in self.local_vlan_map.values():
+            for port in registered_ports:
+                if (
+                    port in lvm.vif_ports
+                    and lvm.vif_ports[port].port_name in port_tags
+                    and port_tags[lvm.vif_ports[port].port_name] != lvm.vlan
+                ):
+                    LOG.info(
+                        _("Port '%(port_name)s' has lost "
+                            "its vlan tag '%(vlan_tag)d'!"),
+                        {'port_name': lvm.vif_ports[port].port_name,
+                         'vlan_tag': lvm.vlan}
+                    )
+                    changed_ports.add(port)
+        return changed_ports
+
     def update_ancillary_ports(self, registered_ports):
         ports = set()
         for bridge in self.ancillary_brs:

neutron/tests/unit/ofagent/test_ofa_neutron_agent.py

@@ -24,6 +24,7 @@ from oslo.config import cfg
 import testtools
 
 from neutron.agent.linux import ip_lib
+from neutron.agent.linux import ovs_lib
 from neutron.agent.linux import utils
 from neutron.openstack.common import importutils
 from neutron.plugins.common import constants as p_const
@@ -310,9 +311,14 @@ class TestOFANeutronAgent(OFAAgentTestCase):
         self._test_port_dead(self.mod_agent.DEAD_VLAN_TAG)
 
     def mock_scan_ports(self, vif_port_set=None, registered_ports=None,
-                        updated_ports=None):
+                        updated_ports=None, port_tags_dict=None):
-        with mock.patch.object(self.agent.int_br, 'get_vif_port_set',
+        port_tags_dict = port_tags_dict or {}
-                               return_value=vif_port_set):
+        with contextlib.nested(
+            mock.patch.object(self.agent.int_br, 'get_vif_port_set',
+                              return_value=vif_port_set),
+            mock.patch.object(self.agent.int_br, 'get_port_tag_dict',
+                              return_value=port_tags_dict)
+        ):
             return self.agent.scan_ports(registered_ports, updated_ports)
 
     def test_scan_ports_returns_current_only_for_unchanged_ports(self):
@@ -365,6 +371,25 @@ class TestOFANeutronAgent(OFAAgentTestCase):
                                       updated_ports)
         self.assertEqual(expected, actual)
 
+    def test_update_ports_returns_lost_vlan_port(self):
+        br = self.mod_agent.OVSBridge('br-int', 'fake_helper', self.ryuapp)
+        mac = "ca:fe:de:ad:be:ef"
+        port = ovs_lib.VifPort(1, 1, 1, mac, br)
+        lvm = self.mod_agent.LocalVLANMapping(
+            1, '1', None, 1, {port.vif_id: port})
+        local_vlan_map = {'1': lvm}
+        vif_port_set = set([1, 3])
+        registered_ports = set([1, 2])
+        port_tags_dict = {1: []}
+        expected = dict(
+            added=set([3]), current=vif_port_set,
+            removed=set([2]), updated=set([1])
+        )
+        with mock.patch.dict(self.agent.local_vlan_map, local_vlan_map):
+            actual = self.mock_scan_ports(
+                vif_port_set, registered_ports, port_tags_dict=port_tags_dict)
+        self.assertEqual(expected, actual)
+
     def test_treat_devices_added_returns_true_for_missing_device(self):
         with mock.patch.object(self.agent.plugin_rpc, 'get_device_details',
                                side_effect=Exception()):