Add IPv6 Prefix Delegation support for DVR

Unlike Legacy routers, DVR Edge Routers have their gateway
interfaces in the SNAT namespace as opposed to the router
namespace.  Added a new method to the router_info class,
get_gw_ns_name(), so callers can determine which namespace
the gateway device lives in.  This can then be over-ridden
in the DVR Edge router class.

The Prefix Delegation code will also now listen on the
update_router event from the l3-agent and reset the namespace
name if it changes.

Closes-Bug: #1541406
Change-Id: If6ada5027d0483fac7fc3ff935fee1edfc6e2759

neutron/agent/l3/dvr_edge_router.py

@@ -33,6 +33,9 @@ class DvrEdgeRouter(dvr_local_router.DvrLocalRouter):
             self.router_id, self.agent_conf, self.driver, self.use_ipv6)
         self.snat_iptables_manager = None
 
+    def get_gw_ns_name(self):
+        return self.snat_namespace.name
+
     def external_gateway_added(self, ex_gw_port, interface_name):
         super(DvrEdgeRouter, self).external_gateway_added(
             ex_gw_port, interface_name)

neutron/agent/l3/router_info.py

@@ -122,6 +122,9 @@ class RouterInfo(object):
     def get_external_device_interface_name(self, ex_gw_port):
         return self.get_external_device_name(ex_gw_port['id'])
 
+    def get_gw_ns_name(self):
+        return self.ns_name
+
     def _update_routing_table(self, operation, route, namespace):
         cmd = ['ip', 'route', operation, 'to', route['destination'],
                'via', route['nexthop']]

neutron/agent/linux/pd.py

@@ -24,7 +24,7 @@ from oslo_utils import netutils
 import six
 from stevedore import driver
 
-from neutron._i18n import _
+from neutron._i18n import _, _LE
 from neutron.callbacks import events
 from neutron.callbacks import registry
 from neutron.callbacks import resources
@@ -57,6 +57,9 @@ class PrefixDelegation(object):
         registry.subscribe(add_router,
                            resources.ROUTER,
                            events.BEFORE_CREATE)
+        registry.subscribe(update_router,
+                           resources.ROUTER,
+                           events.AFTER_UPDATE)
         registry.subscribe(remove_router,
                            resources.ROUTER,
                            events.AFTER_DELETE)
@@ -329,12 +332,24 @@ def get_router_entry(ns_name):
 def add_router(resource, event, l3_agent, **kwargs):
     added_router = kwargs['router']
     router = l3_agent.pd.routers.get(added_router.router_id)
+    gw_ns_name = added_router.get_gw_ns_name()
     if not router:
         l3_agent.pd.routers[added_router.router_id] = (
-            get_router_entry(added_router.ns_name))
+            get_router_entry(gw_ns_name))
     else:
         # This will happen during l3 agent restart
-        router['ns_name'] = added_router.ns_name
+        router['ns_name'] = gw_ns_name
+
+
+@utils.synchronized("l3-agent-pd")
+def update_router(resource, event, l3_agent, **kwargs):
+    updated_router = kwargs['router']
+    router = l3_agent.pd.routers.get(updated_router.router_id)
+    if not router:
+        LOG.exception(_LE("Router to be updated is not in internal routers "
+                          "list: %s"), updated_router.router_id)
+    else:
+        router['ns_name'] = updated_router.get_gw_ns_name()
 
 
 class PDInfo(object):

neutron/tests/unit/agent/l3/test_agent.py

@@ -670,8 +670,10 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
         self._set_ri_kwargs(mock.Mock(), router['id'], router)
         ri = dvr_router.DvrEdgeRouter(HOSTNAME, **self.ri_kwargs)
         # Make sure that ri.snat_namespace object is created when the
-        # router is initialized
+        # router is initialized, and that it's name matches the gw
+        # namespace name
         self.assertIsNotNone(ri.snat_namespace)
+        self.assertEqual(ri.snat_namespace.name, ri.get_gw_ns_name())
 
     def test_ext_gw_updated_calling_snat_ns_delete_if_gw_port_host_none(
         self):

neutron/tests/unit/agent/l3/test_dvr_local_router.py

@@ -164,6 +164,10 @@ class TestDvrRouterOperations(base.BaseTestCase):
         self.ri_kwargs['router_id'] = router_id
         self.ri_kwargs['router'] = router
 
+    def test_gw_ns_name(self):
+        ri = self._create_router()
+        self.assertEqual(ri.ns_name, ri.get_gw_ns_name())
+
     def test_create_dvr_fip_interfaces_update(self):
         ri = self._create_router()
         fip_agent_port = {'subnets': []}

neutron/tests/unit/agent/linux/test_pd.py

@@ -12,6 +12,9 @@
 
 import mock
 
+from neutron.agent.l3 import dvr_edge_router
+from neutron.agent.l3 import dvr_local_router
+from neutron.agent.l3 import legacy_router
 from neutron.agent.linux import pd
 from neutron.tests import base as tests_base
 
@@ -24,8 +27,68 @@ class FakeRouter(object):
 class TestPrefixDelegation(tests_base.DietTestCase):
     def test_remove_router(self):
         l3_agent = mock.Mock()
-        router_id = 1
+        router_id = '1'
         l3_agent.pd.routers = {router_id: pd.get_router_entry(None)}
         pd.remove_router(None, None, l3_agent, router=FakeRouter(router_id))
         self.assertTrue(l3_agent.pd.delete_router_pd.called)
         self.assertEqual({}, l3_agent.pd.routers)
+
+    def _test_add_update_pd(self, l3_agent, router, ns_name):
+        # add entry
+        pd.add_router(None, None, l3_agent, router=router)
+        pd_router = l3_agent.pd.routers.get(router.router_id)
+        self.assertEqual(ns_name, pd_router.get('ns_name'))
+
+        # clear namespace name, update entry
+        pd_router['ns_name'] = None
+        pd.update_router(None, None, l3_agent, router=router)
+        pd_router = l3_agent.pd.routers.get(router.router_id)
+        self.assertEqual(ns_name, pd_router.get('ns_name'))
+
+    def test_add_update_dvr_edge_router(self):
+        l3_agent = mock.Mock()
+        l3_agent.pd.routers = {}
+        router_id = '1'
+        ri = dvr_edge_router.DvrEdgeRouter(l3_agent,
+                                           'host',
+                                           router_id,
+                                           mock.Mock(),
+                                           mock.Mock(),
+                                           mock.Mock())
+        ns_name = ri.snat_namespace.name
+        self._test_add_update_pd(l3_agent, ri, ns_name)
+
+    def test_add_update_dvr_local_router(self):
+        l3_agent = mock.Mock()
+        l3_agent.pd.routers = {}
+        router_id = '1'
+        ri = dvr_local_router.DvrLocalRouter(l3_agent,
+                                           'host',
+                                           router_id,
+                                           mock.Mock(),
+                                           mock.Mock(),
+                                           mock.Mock())
+        ns_name = ri.ns_name
+        self._test_add_update_pd(l3_agent, ri, ns_name)
+
+    def test_add_update_legacy_router(self):
+        l3_agent = mock.Mock()
+        l3_agent.pd.routers = {}
+        router_id = '1'
+        ri = legacy_router.LegacyRouter(l3_agent,
+                                        router_id,
+                                        mock.Mock(),
+                                        mock.Mock(),
+                                        mock.Mock())
+        ns_name = ri.ns_name
+        self._test_add_update_pd(l3_agent, ri, ns_name)
+
+    def test_update_no_router_exception(self):
+        l3_agent = mock.Mock()
+        l3_agent.pd.routers = {}
+        router = mock.Mock()
+        router.router_id = '1'
+
+        with mock.patch.object(pd.LOG, 'exception') as log:
+            pd.update_router(None, None, l3_agent, router=router)
+            self.assertTrue(log.called)