Add router-interface-fip extension from networking-midonet

This is a part of the stadium implosion effort. [1]

References:
    http://docs.openstack.org/developer/networking-midonet/specs/mitaka/router-interface-fip.html

[1] https://review.openstack.org/#/c/389397/

Closes-Bug: #1648517
Related-Bug: #1566191  (RFE bug)
Change-Id: I8641f8d200fcecc9bc2cedb49321c14fa610be86

api-ref/source/v2/index.rst

@@ -59,3 +59,7 @@ Logging Resource (networking-midonet)
 #####################################
 .. include:: logging_resource.inc
 .. include:: firewall_log.inc
+#################################################
+Router interface floating IP (networking-midonet)
+#################################################
+.. include:: router-interface-fip.inc

api-ref/source/v2/router-interface-fip.inc

@@ -0,0 +1,14 @@
+.. -*- rst -*-
+
+============================
+Router Interface floating IP
+============================
+
+.. note:: Currently this extension ``router-interface-fip`` is only available for networking-midonet.
+
+This extension ``router-interface-fip`` indicates the ability to
+associate floating IPs to internal interfaces of a router.
+(Without this extension, floating IPs can be associated only to
+the gateway interface of a router.)
+
+This extension does not introduce any resources or attributes.

neutron_lib/api/definitions/router_interface_fip.py

@@ -0,0 +1,57 @@
+# All rights reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from neutron_lib.api.definitions import l3
+
+# The alias of the extension.
+ALIAS = 'router-interface-fip'
+
+# Whether or not this extension is simply signaling behavior to the user
+# or it actively modifies the attribute map.
+IS_SHIM_EXTENSION = True
+
+# Whether the extension is marking the adoption of standardattr model for
+# legacy resources, or introducing new standardattr attributes. False or
+# None if the standardattr model is adopted since the introduction of
+# resource extension.
+# If this is True, the alias for the extension should be prefixed with
+# 'standard-attr-'.
+IS_STANDARD_ATTR_EXTENSION = False
+
+# The name of the extension.
+NAME = 'Router interface FIP Extension'
+
+# The description of the extension.
+DESCRIPTION = "Router interface FIP Extension"
+
+# A timestamp of when the extension was introduced.
+UPDATED_TIMESTAMP = "2015-11-11T10:00:00-00:00"
+
+# The resource attribute map for the extension. It is effectively the
+# bulk of the API contract alongside ACTION_MAP
+RESOURCE_ATTRIBUTE_MAP = {}
+
+# The subresource attribute map for the extension.
+SUB_RESOURCE_ATTRIBUTE_MAP = None
+
+# The action map.
+ACTION_MAP = {}
+
+# The list of required extensions.
+REQUIRED_EXTENSIONS = [
+    l3.ALIAS,
+]
+
+# The list of optional extensions.
+OPTIONAL_EXTENSIONS = []

neutron_lib/tests/unit/api/definitions/test_router_interface_fip.py

@@ -0,0 +1,20 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from neutron_lib.api.definitions import router_interface_fip
+from neutron_lib.tests.unit.api.definitions import base
+
+
+class RouterInterfaceFipDefinitionTestCase(base.DefinitionBaseTestCase):
+    extension_module = router_interface_fip
+    extension_resources = ()
+    extension_attributes = ()

releasenotes/notes/router-interface-fip-1e79b7909f8b264f.yaml

@@ -0,0 +1,3 @@
+---
+features:
+  - API reference and definition for networking-midonet's ``router-interface-fip`` extension.