Update auto-addresses on MAC change

On MAC update add an entry for auto-addressed IPs so
that they get removed and re-allocated.

Also add a check to ensure the length of fixed_ips in the result
is what was expected i.e. ensure we replaced the IP's(as is the current
behaviour) and not just added to the list.

Change-Id: Id1eadce7a18ba82d6c1a42f1afb0267f076f9308
Closes-Bug: #1671548

neutron/db/ipam_pluggable_backend.py

@@ -335,6 +335,25 @@ class IpamPluggableBackend(ipam_backend_mixin.IpamBackendMixin):
     def update_port_with_ips(self, context, host, db_port, new_port, new_mac):
         changes = self.Changes(add=[], original=[], remove=[])
 
+        auto_assign_subnets = []
+        if new_mac:
+            original = self._make_port_dict(db_port, process_extensions=False)
+            if original.get('mac_address') != new_mac:
+                original_ips = original.get('fixed_ips', [])
+                new_ips = new_port.setdefault('fixed_ips', original_ips)
+                new_ips_subnets = [new_ip['subnet_id'] for new_ip in new_ips]
+                for orig_ip in original_ips:
+                    if ipv6_utils.is_eui64_address(orig_ip.get('ip_address')):
+                        subnet_to_delete = {}
+                        subnet_to_delete['subnet_id'] = orig_ip['subnet_id']
+                        subnet_to_delete['delete_subnet'] = True
+                        auto_assign_subnets.append(subnet_to_delete)
+                        try:
+                            i = new_ips_subnets.index(orig_ip['subnet_id'])
+                            new_ips[i] = subnet_to_delete
+                        except ValueError:
+                            new_ips.append(subnet_to_delete)
+
         if 'fixed_ips' in new_port:
             original = self._make_port_dict(db_port,
                                             process_extensions=False)
@@ -362,6 +381,14 @@ class IpamPluggableBackend(ipam_backend_mixin.IpamBackendMixin):
             self._update_db_port(context, db_port, new_port, network_id,
                                  new_mac)
             getattr(db_port, 'fixed_ips')  # refresh relationship before return
+
+            if auto_assign_subnets:
+                port_copy = copy.deepcopy(original)
+                port_copy.update(new_port)
+                port_copy['fixed_ips'] = auto_assign_subnets
+                self.allocate_ips_for_port_and_store(context,
+                            {'port': port_copy}, port_copy['id'])
+
         except Exception:
             with excutils.save_and_reraise_exception():
                 if 'fixed_ips' in new_port:

neutron/tests/unit/db/test_db_base_plugin_v2.py

@@ -1381,8 +1381,6 @@ fixed_ips=ip_address%%3D%s&fixed_ips=ip_address%%3D%s&fixed_ips=subnet_id%%3D%s
                 subnet_cidr = subnet['subnet']['cidr']
                 eui_addr = str(netutils.get_ipv6_addr_by_EUI64(subnet_cidr,
                                                                port_mac))
-                # TODO(kevinbenton): remove after bug 1671548 fix
-                eui_addr = mock.ANY
                 fip = {'ip_address': eui_addr,
                        'subnet_id': subnet['subnet']['id']}
             self.assertIn(fip, new_port['port']['fixed_ips'])
@@ -1408,6 +1406,9 @@ fixed_ips=ip_address%%3D%s&fixed_ips=ip_address%%3D%s&fixed_ips=subnet_id%%3D%s
                 self.assertEqual(new_mac, result['port']['mac_address'])
                 if updated_fixed_ips is None:
                     self._verify_ips_after_mac_change(port, result)
+                else:
+                    self.assertEqual(len(updated_fixed_ips),
+                         len(result['port']['fixed_ips']))
             else:
                 error = self.deserialize(self.fmt, res)
                 self.assertEqual(expected_error,