Merge "Support MTU advertisement using IPv6 RAs"

neutron/agent/linux/ra.py

@@ -53,6 +53,10 @@ CONFIG_TEMPLATE = jinja2.Template("""interface {{ interface_name }}
    MinRtrAdvInterval {{ min_rtr_adv_interval }};
    MaxRtrAdvInterval {{ max_rtr_adv_interval }};
 
+   {% if network_mtu >= constants.IPV6_MIN_MTU %}
+   AdvLinkMTU {{network_mtu}};
+   {% endif %}
+
    {% if constants.DHCPV6_STATELESS in ra_modes %}
    AdvOtherConfigFlag on;
    {% endif %}
@@ -101,6 +105,7 @@ class DaemonMonitor(object):
                                               'radvd.conf',
                                               True)
         buf = six.StringIO()
+        network_mtu = 0
         for p in router_ports:
             subnets = p.get('subnets', [])
             v6_subnets = [subnet for subnet in subnets if
@@ -118,6 +123,9 @@ class DaemonMonitor(object):
                 subnet['ipv6_ra_mode'] == constants.IPV6_SLAAC]
             dns_servers = list(iter_chain(*[subnet['dns_nameservers'] for
                 subnet in slaac_subnets if subnet.get('dns_nameservers')]))
+            if self._agent_conf.advertise_mtu:
+                network_mtu = p.get('mtu', 0)
+
             buf.write('%s' % CONFIG_TEMPLATE.render(
                 ra_modes=list(ra_modes),
                 interface_name=interface_name,
@@ -126,7 +134,8 @@ class DaemonMonitor(object):
                 dns_servers=dns_servers[0:MAX_RDNSS_ENTRIES],
                 constants=constants,
                 min_rtr_adv_interval=self._agent_conf.min_rtr_adv_interval,
-                max_rtr_adv_interval=self._agent_conf.max_rtr_adv_interval))
+                max_rtr_adv_interval=self._agent_conf.max_rtr_adv_interval,
+                network_mtu=int(network_mtu)))
 
         common_utils.replace_file(radvd_conf, buf.getvalue())
         return radvd_conf

neutron/common/config.py

@@ -157,9 +157,8 @@ core_opts = [
                       'there are any events to send.')),
     cfg.BoolOpt('advertise_mtu', default=True,
                 help=_('If True, advertise network MTU values if core plugin '
-                       'calculates them. Currently, the only way to advertise '
+                       'calculates them. MTU is advertised to running '
-                       'MTU to running instances is using corresponding DHCP '
+                       'instances via DHCP and RA MTU options.')),
-                       'option.')),
     cfg.StrOpt('ipam_driver',
                help=_("Neutron IPAM (IP address management) driver to use. "
                       "If ipam_driver is not set (default behavior), no IPAM "

neutron/db/l3_db.py

@@ -1424,7 +1424,18 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
             subnets_by_network[subnet['network_id']].append(subnet)
         return subnets_by_network
 
-    def _populate_subnets_for_ports(self, context, ports):
+    def _get_mtus_by_network_list(self, context, network_ids):
+        if not network_ids:
+            return {}
+        filters = {'network_id': network_ids}
+        fields = ['id', 'mtu']
+        networks = self._core_plugin.get_networks(context, filters=filters,
+                                                  fields=fields)
+        mtus_by_network = dict((network['id'], network.get('mtu', 0))
+                               for network in networks)
+        return mtus_by_network
+
+    def _populate_mtu_and_subnets_for_ports(self, context, ports):
         """Populate ports with subnets.
 
         These ports already have fixed_ips populated.
@@ -1432,6 +1443,7 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
         network_ids = [p['network_id']
                        for p in self._each_port_having_fixed_ips(ports)]
 
+        mtus_by_network = self._get_mtus_by_network_list(context, network_ids)
         subnets_by_network = self._get_subnets_by_network_list(
             context, network_ids)
 
@@ -1469,6 +1481,7 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
                     port['extra_subnets'].append(subnet_info)
 
             port['address_scopes'].update(scopes)
+            port['mtu'] = mtus_by_network.get(port['network_id'], 0)
 
     def _process_floating_ips(self, context, routers_dict, floating_ips):
         for floating_ip in floating_ips:
@@ -1505,7 +1518,7 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
             context, router_ids=router_ids, active=active)
         ports_to_populate = [router['gw_port'] for router in routers
                              if router.get('gw_port')] + interfaces
-        self._populate_subnets_for_ports(context, ports_to_populate)
+        self._populate_mtu_and_subnets_for_ports(context, ports_to_populate)
         routers_dict = dict((router['id'], router) for router in routers)
         self._process_floating_ips(context, routers_dict, floating_ips)
         self._process_interfaces(routers_dict, interfaces)

neutron/db/l3_dvr_db.py

@@ -513,7 +513,7 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
             if router.get(l3_const.SNAT_ROUTER_INTF_KEY):
                 ports_to_populate += router[l3_const.SNAT_ROUTER_INTF_KEY]
         ports_to_populate += interfaces
-        self._populate_subnets_for_ports(context, ports_to_populate)
+        self._populate_mtu_and_subnets_for_ports(context, ports_to_populate)
         self._process_interfaces(routers_dict, interfaces)
         return list(routers_dict.values())
 
@@ -583,12 +583,13 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
                 agent_port = p_utils.create_port(self._core_plugin, context,
                                                  {'port': port_data})
                 if agent_port:
-                    self._populate_subnets_for_ports(context, [agent_port])
+                    self._populate_mtu_and_subnets_for_ports(context,
+                                                             [agent_port])
                     return agent_port
                 msg = _("Unable to create the Agent Gateway Port")
                 raise n_exc.BadRequest(resource='router', msg=msg)
             else:
-                self._populate_subnets_for_ports(context, [f_port])
+                self._populate_mtu_and_subnets_for_ports(context, [f_port])
                 return f_port
 
     def _get_snat_interface_ports_for_router(self, context, router_id):
@@ -628,7 +629,8 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
             context.session.add(router_port)
 
         if do_pop:
-            return self._populate_subnets_for_ports(context, [snat_port])
+            return self._populate_mtu_and_subnets_for_ports(context,
+                                                            [snat_port])
         return snat_port
 
     def _create_snat_intf_ports_if_not_exists(self, context, router):
@@ -641,7 +643,7 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
         port_list = self._get_snat_interface_ports_for_router(
             context, router.id)
         if port_list:
-            self._populate_subnets_for_ports(context, port_list)
+            self._populate_mtu_and_subnets_for_ports(context, port_list)
             return port_list
         port_list = []
 
@@ -663,7 +665,7 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
                     intf['fixed_ips'][0]['subnet_id'], do_pop=False)
                 port_list.append(snat_port)
         if port_list:
-            self._populate_subnets_for_ports(context, port_list)
+            self._populate_mtu_and_subnets_for_ports(context, port_list)
         return port_list
 
     def _generate_arp_table_and_notify_agent(

neutron/db/l3_hamode_db.py

@@ -635,7 +635,7 @@ class L3_HA_NAT_db_mixin(l3_dvr_db.L3_NAT_with_dvr_db_mixin,
         for router in routers_dict.values():
             interface = router.get(constants.HA_INTERFACE_KEY)
             if interface:
-                self._populate_subnets_for_ports(context, [interface])
+                self._populate_mtu_and_subnets_for_ports(context, [interface])
 
         return list(routers_dict.values())
 

neutron/tests/common/l3_test_common.py

@@ -177,7 +177,7 @@ def router_append_interface(router, count=1, ip_version=4, ra_mode=None,
 
 def router_append_subnet(router, count=1, ip_version=4,
                          ipv6_subnet_modes=None, interface_id=None,
-                         dns_nameservers=None):
+                         dns_nameservers=None, network_mtu=0):
     if ip_version == 6:
         subnet_mode_none = {'ra_mode': None, 'address_mode': None}
         if not ipv6_subnet_modes:
@@ -238,6 +238,7 @@ def router_append_subnet(router, count=1, ip_version=4,
         mac_address.dialect = netaddr.mac_unix
         interfaces.append(
             {'id': _uuid(),
+             'mtu': network_mtu,
              'network_id': _uuid(),
              'admin_state_up': True,
              'mac_address': str(mac_address),

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

@@ -1306,8 +1306,8 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
             expected_calls.append(mock.call().disable())
         return expected_calls
 
-    def _process_router_ipv6_subnet_added(
+    def _process_router_ipv6_subnet_added(self, router,
-            self, router, ipv6_subnet_modes=None, dns_nameservers=None):
+            ipv6_subnet_modes=None, dns_nameservers=None, network_mtu=0):
         agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
         ri = l3router.RouterInfo(router['id'], router, **self.ri_kwargs)
         agent.external_gateway_added = mock.Mock()
@@ -1319,7 +1319,8 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
             count=len(ipv6_subnet_modes),
             ip_version=6,
             ipv6_subnet_modes=ipv6_subnet_modes,
-            dns_nameservers=dns_nameservers)
+            dns_nameservers=dns_nameservers,
+            network_mtu=network_mtu)
         # Reassign the router object to RouterInfo
         self._process_router_instance_for_agent(agent, ri, router)
         return ri
@@ -2299,6 +2300,25 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
         self.assertIn(_join('-p', pidfile), cmd)
         self.assertIn(_join('-m', 'syslog'), cmd)
 
+    def test_generate_radvd_mtu_conf(self):
+        router = l3_test_common.prepare_router_data()
+        ipv6_subnet_modes = [{'ra_mode': l3_constants.IPV6_SLAAC,
+                             'address_mode': l3_constants.IPV6_SLAAC}]
+        network_mtu = '1446'
+        ri = self._process_router_ipv6_subnet_added(router,
+                                                    ipv6_subnet_modes,
+                                                    None,
+                                                    network_mtu)
+        expected = "AdvLinkMTU 1446"
+        ri.agent_conf.set_override('advertise_mtu', False)
+        ri.radvd._generate_radvd_conf(router[l3_constants.INTERFACE_KEY])
+        self.assertNotIn(expected, self.utils_replace_file.call_args[0][1])
+
+        # Verify that MTU is advertised when advertise_mtu is True
+        ri.agent_conf.set_override('advertise_mtu', True)
+        ri.radvd._generate_radvd_conf(router[l3_constants.INTERFACE_KEY])
+        self.assertIn(expected, self.utils_replace_file.call_args[0][1])
+
     def test_generate_radvd_conf_other_and_managed_flag(self):
         # expected = {ra_mode: (AdvOtherConfigFlag, AdvManagedFlag), ...}
         expected = {l3_constants.IPV6_SLAAC: (False, False),

neutron/tests/unit/db/test_l3_db.py

@@ -72,7 +72,10 @@ class TestL3_NAT_dbonly_mixin(base.BaseTestCase):
     def test__populate_ports_for_subnets_none(self):
         """Basic test that the method runs correctly with no ports"""
         ports = []
-        self.db._populate_subnets_for_ports(mock.sentinel.context, ports)
+        with mock.patch.object(manager.NeutronManager, 'get_plugin') as get_p:
+            get_p().get_networks.return_value = []
+            self.db._populate_mtu_and_subnets_for_ports(mock.sentinel.context,
+                                                        ports)
         self.assertEqual([], ports)
 
     @mock.patch.object(l3_db.L3_NAT_dbonly_mixin,
@@ -91,14 +94,19 @@ class TestL3_NAT_dbonly_mixin(base.BaseTestCase):
         ports = [{'network_id': 'net_id',
                   'id': 'port_id',
                   'fixed_ips': [{'subnet_id': mock.sentinel.subnet_id}]}]
-        self.db._populate_subnets_for_ports(mock.sentinel.context, ports)
+        with mock.patch.object(manager.NeutronManager, 'get_plugin') as get_p:
-        keys = ('id', 'cidr', 'gateway_ip', 'ipv6_ra_mode', 'subnetpool_id',
+            get_p().get_networks.return_value = [{'id': 'net_id', 'mtu': 1446}]
-                'dns_nameservers')
+            self.db._populate_mtu_and_subnets_for_ports(mock.sentinel.context,
+                                                        ports)
+            keys = ('id', 'cidr', 'gateway_ip', 'ipv6_ra_mode',
+                    'subnetpool_id', 'dns_nameservers')
             address_scopes = {4: None, 6: mock.sentinel.address_scope_id}
             self.assertEqual([{'extra_subnets': [],
-                           'fixed_ips': [{'subnet_id': mock.sentinel.subnet_id,
+                               'fixed_ips': [{'subnet_id':
+                                              mock.sentinel.subnet_id,
                                               'prefixlen': 64}],
                                'id': 'port_id',
+                               'mtu': 1446,
                                'network_id': 'net_id',
                                'subnets': [{k: subnet[k] for k in keys}],
                                'address_scopes': address_scopes}], ports)

releasenotes/notes/mtu-selection-and-advertisement-ab29f9ec43140224.yaml

@@ -0,0 +1,9 @@
+---
+prelude: >
+    Support for MTU selection and advertisement.
+features:
+  - When advertise_mtu is set in the config, Neutron supports
+    advertising the LinkMTU using Router Advertisements.
+other:
+  - For details please read `Blueprint mtu-selection-and-advertisement
+    <https://specs.openstack.org/openstack/neutron-specs/specs/kilo/mtu-selection-and-advertisement.html>`_.