L2-Adjacency support

The following patch adds the support for L2-Adjacency to indicate if
there is L2 adjacency between the ports on a network.

Partially-Implements: blueprint routed-networks

Change-Id: Id2d4331568886bee52e78e1c138f1475cc89342b

neutron/extensions/l2_adjacency.py

@@ -0,0 +1,58 @@
+# Copyright (c) 2016 NEC Technologies Ltd.
+# 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.api import extensions
+
+
+L2_ADJACENCY = 'l2_adjacency'
+EXTENDED_ATTRIBUTES_2_0 = {
+    'networks': {
+        L2_ADJACENCY: {'allow_post': False,
+                       'allow_put': False,
+                       'is_visible': True}
+    }
+}
+
+
+class L2_adjacency(extensions.ExtensionDescriptor):
+    """Extension class supporting L2 Adjacency for Routed Networks
+
+    The following class is used by neutron's extension framework
+    to provide metadata related to the L2 Adjacency for Neutron
+    Routed Network, exposing the same to clients.
+    No new resources have been defined by this extension.
+    """
+
+    @classmethod
+    def get_name(cls):
+        return "L2 Adjacency"
+
+    @classmethod
+    def get_alias(cls):
+        return "l2_adjacency"
+
+    @classmethod
+    def get_description(cls):
+        return "Display L2 Adjacency for Neutron Networks."
+
+    @classmethod
+    def get_updated(cls):
+        return "2016-04-12T16:00:00-00:00"
+
+    def get_extended_resources(self, version):
+        if version == "2.0":
+            return EXTENDED_ATTRIBUTES_2_0
+        else:
+            return {}

neutron/services/segments/plugin.py

@@ -20,11 +20,22 @@ from neutron.api.v2 import attributes
 from neutron.db import common_db_mixin
 from neutron.db import models_v2
 from neutron.extensions import ip_allocation
+from neutron.extensions import l2_adjacency
 from neutron.extensions import segment
 from neutron import manager
 from neutron.services.segments import db
 
 
+def _extend_network_dict_binding(plugin, network_res, network_db):
+    if not manager.NeutronManager.get_service_plugins().get('segments'):
+        return
+
+    # TODO(carl_baldwin) Make this work with service subnets when it's a thing.
+    is_adjacent = (not network_db.subnets
+                   or not network_db.subnets[0].segment_id)
+    network_res[l2_adjacency.L2_ADJACENCY] = is_adjacent
+
+
 def _extend_subnet_dict_binding(plugin, subnet_res, subnet_db):
     subnet_res['segment_id'] = subnet_db.get('segment_id')
 
@@ -50,9 +61,11 @@ class Plugin(db.SegmentDbMixin, segment.SegmentPluginBase):
 
     _instance = None
 
-    supported_extension_aliases = ["segment", "ip_allocation"]
+    supported_extension_aliases = ["segment", "ip_allocation", "l2_adjacency"]
 
     def __init__(self):
+        common_db_mixin.CommonDbMixin.register_dict_extend_funcs(
+            attributes.NETWORKS, [_extend_network_dict_binding])
         common_db_mixin.CommonDbMixin.register_dict_extend_funcs(
             attributes.SUBNETS, [_extend_subnet_dict_binding])
         common_db_mixin.CommonDbMixin.register_dict_extend_funcs(

neutron/tests/unit/extensions/test_segment.py

@@ -30,6 +30,7 @@ from neutron.db import db_base_plugin_v2
 from neutron.db import portbindings_db
 from neutron.db import segments_db
 from neutron.extensions import ip_allocation
+from neutron.extensions import l2_adjacency
 from neutron.extensions import portbindings
 from neutron.extensions import segment as ext_segment
 from neutron.plugins.common import constants as p_constants
@@ -670,6 +671,8 @@ class TestSegmentAwareIpam(SegmentTestCase):
                          segment_id=segment['segment']['id'],
                          ip_version=ip_version,
                          cidr=cidr) as subnet:
+            self._validate_l2_adjacency(network['network']['id'],
+                                        is_adjacent=False)
             return network, segment, subnet
 
     def _create_test_segments_with_subnets(self, num):
@@ -753,6 +756,8 @@ class TestSegmentAwareIpam(SegmentTestCase):
                     network_id=network['network']['id'],
                     physical_network='physnet')
 
+        self._validate_l2_adjacency(network['network']['id'], is_adjacent=True)
+
         # Map the host to the segment
         self._setup_host_mappings([(segment['segment']['id'], 'fakehost')])
 
@@ -877,6 +882,8 @@ class TestSegmentAwareIpam(SegmentTestCase):
         with self.subnet(network=network,
                          segment_id=segment['segment']['id']) as subnet:
             self._validate_deferred_ip_allocation(port['port']['id'])
+            self._validate_l2_adjacency(network['network']['id'],
+                                        is_adjacent=False)
             # Try requesting an IP (but the only subnet is on a segment)
             data = {'port': {
                 'fixed_ips': [{'subnet_id': subnet['subnet']['id']}]}}
@@ -888,6 +895,12 @@ class TestSegmentAwareIpam(SegmentTestCase):
         self.assertEqual(webob.exc.HTTPOk.code, response.status_int)
         self._assert_one_ip_in_subnet(response, subnet['subnet']['cidr'])
 
+    def _validate_l2_adjacency(self, network_id, is_adjacent):
+        request = self.new_show_request('networks', network_id)
+        response = self.deserialize(self.fmt, request.get_response(self.api))
+        self.assertEqual(is_adjacent,
+                         response['network'][l2_adjacency.L2_ADJACENCY])
+
     def _validate_deferred_ip_allocation(self, port_id):
         request = self.new_show_request('ports', port_id)
         response = self.deserialize(self.fmt, request.get_response(self.api))

releasenotes/notes/l2_adjacency-e6e54e5ff9aad9b7.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    The new l2_adjacency extension adds an l2_adjacency field to the network,
+    to indicate whether or not there is guaranteed L2 adjacency between the
+    ports on that Network.  Routed network implementations would typically set
+    l2_adjacency to False.