Add ext-gw-mode support to ML2

Closes-Bug: #1212772

ML2 doesn't support ext-gw-mode, resulting in L3 agents not
setting-up NAT rules in neutron routers (currently, l3 agents
will assume enable_snat=false if plugin doesn't provide this
parameter as described in bug 1212868)

This patchset adds the support of ext-gw-mode to ML2 plugin.

In order to support ext-gw-mode alembic migration (as well as
other potential migrations on plugin dbs), folsom_initial
migration script is fixed to include ML2 plugin. Otherwise
databases won't be set-up during migration script (but at
plugin startup by sqlalchemy), resulting in migration failures.

Change-Id: I95ec18e0a4f0e5b661f3a5d679c434f18f100fa6

neutron/db/migration/alembic_migrations/versions/128e042a2b68_ext_gw_mode.py

@@ -33,6 +33,7 @@ migration_for_plugins = [
     'neutron.plugins.hyperv.hyperv_neutron_plugin.HyperVNeutronPlugin',
     'neutron.plugins.linuxbridge.lb_neutron_plugin.LinuxBridgePluginV2',
     'neutron.plugins.metaplugin.meta_neutron_plugin.MetaPluginV2',
+    'neutron.plugins.ml2.plugin.Ml2Plugin',
     'neutron.plugins.nec.nec_plugin.NECPluginV2',
     'neutron.plugins.nicira.NeutronPlugin.NvpPluginV2',
     'neutron.plugins.openvswitch.ovs_neutron_plugin.OVSNeutronPluginV2',

neutron/db/migration/alembic_migrations/versions/folsom_initial.py

@@ -29,7 +29,7 @@ PLUGINS = {
     'cisco': 'neutron.plugins.cisco.network_plugin.PluginV2',
     'lbr': 'neutron.plugins.linuxbridge.lb_neutron_plugin.LinuxBridgePluginV2',
     'meta': 'neutron.plugins.metaplugin.meta_neutron_plugin.MetaPluginV2',
-    'ml2': 'neutron.plugins.ml2.ml2_plugin.Ml2Plugin',
+    'ml2': 'neutron.plugins.ml2.plugin.Ml2Plugin',
     'nec': 'neutron.plugins.nec.nec_plugin.NECPluginV2',
     'nvp': 'neutron.plugins.nicira.NeutronPlugin.NvpPluginV2',
     'ovs': 'neutron.plugins.openvswitch.ovs_neutron_plugin.OVSNeutronPluginV2',

neutron/plugins/ml2/plugin.py

@@ -25,6 +25,7 @@ from neutron.common import topics
 from neutron.db import agentschedulers_db
 from neutron.db import db_base_plugin_v2
 from neutron.db import extraroute_db
+from neutron.db import l3_gwmode_db
 from neutron.db import portbindings_db
 from neutron.db import quota_db  # noqa
 from neutron.db import securitygroups_rpc_base as sg_db_rpc
@@ -51,6 +52,7 @@ TYPE_MULTI_SEGMENT = 'multi-segment'
 
 class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                 extraroute_db.ExtraRoute_db_mixin,
+                l3_gwmode_db.L3_NAT_db_mixin,
                 sg_db_rpc.SecurityGroupServerRpcMixin,
                 agentschedulers_db.L3AgentSchedulerDbMixin,
                 agentschedulers_db.DhcpAgentSchedulerDbMixin,
@@ -75,7 +77,7 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
     _supported_extension_aliases = ["provider", "router", "extraroute",
                                     "binding", "quotas", "security-group",
                                     "agent", "l3_agent_scheduler",
-                                    "dhcp_agent_scheduler"]
+                                    "dhcp_agent_scheduler", "ext-gw-mode"]
 
     @property
     def supported_extension_aliases(self):

neutron/tests/unit/ml2/test_ml2_plugin.py

@@ -16,6 +16,7 @@
 from neutron.plugins.ml2 import config as config
 from neutron.tests.unit import _test_extension_portbindings as test_bindings
 from neutron.tests.unit import test_db_plugin as test_plugin
+from neutron.tests.unit import test_extension_ext_gw_mode
 
 
 PLUGIN_NAME = 'neutron.plugins.ml2.plugin.Ml2Plugin'
@@ -69,3 +70,8 @@ class TestMl2PortsV2(test_plugin.TestPortsV2, Ml2PluginV2TestCase):
 class TestMl2PortBindingHost(Ml2PluginV2TestCase,
                              test_bindings.PortBindingsHostTestCaseMixin):
     pass
+
+
+class TestMl2ExtGwModeSupport(Ml2PluginV2TestCase,
+                              test_extension_ext_gw_mode.ExtGwModeTestCase):
+    pass