introduces MTU support for vhost-user

- This change introduces the ability
  to set the MTU for vhost-user interface
  if supported by ovs.
- This change leverages the mtu_request
  option added to the ovs interface in ovs 2.6.
- MTU support enable the use of jumbo frames
  with vhost-user interfaces.

Change-Id: Ide3435b74809605692fa6153c3be3294db80182f

releasenotes/notes/vhost-user-mtu-support-cbc7d02a6665fab1.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - In the ocata cycle support was added for setting
+    the MTU of vhost-user port with ovs.
+  - vhost-user MTU support enable jumbo frames to
+    be used with vhost-user interfaces.
+other:
+  - vhost-user MTU support requires ovs 2.6 or newer.
+    On older versions of ovs, the MTU request will
+    not be made and jumbo frames are not supported.

vif_plug_ovs/linux_net.py

@@ -75,12 +75,12 @@ def create_ovs_vif_port(bridge, dev, iface_id, mac, instance_id,
     _ovs_vsctl(_create_ovs_vif_cmd(bridge, dev, iface_id,
                                    mac, instance_id, interface_type,
                                    vhost_server_path), timeout=timeout)
-    _update_device_mtu(dev, mtu, interface_type)
+    _update_device_mtu(dev, mtu, interface_type, timeout=timeout)
 
 
 @privsep.vif_plug.entrypoint
-def update_ovs_vif_port(dev, mtu=None, interface_type=None):
-    _update_device_mtu(dev, mtu, interface_type)
+def update_ovs_vif_port(dev, mtu=None, interface_type=None, timeout=None):
+    _update_device_mtu(dev, mtu, interface_type, timeout=timeout)
 
 
 @privsep.vif_plug.entrypoint
@@ -168,21 +168,41 @@ def add_bridge_port(bridge, dev):
     processutils.execute('brctl', 'addif', bridge, dev)
 
 
-def _update_device_mtu(dev, mtu, interface_type=None):
-    # Note at present there is no support for setting the
-    # mtu for vhost-user type ports.
-    if mtu and interface_type not in [
-            constants.OVS_VHOSTUSER_INTERFACE_TYPE,
-            constants.OVS_VHOSTUSER_CLIENT_INTERFACE_TYPE]:
+def _update_device_mtu(dev, mtu, interface_type=None, timeout=120):
+    if not mtu:
+        return
+    if interface_type not in [
+        constants.OVS_VHOSTUSER_INTERFACE_TYPE,
+        constants.OVS_VHOSTUSER_CLIENT_INTERFACE_TYPE]:
         _set_device_mtu(dev, mtu)
+    elif _ovs_supports_mtu_requests(timeout=timeout):
+        _set_mtu_request(dev, mtu, timeout=timeout)
     else:
         LOG.debug("MTU not set on %(interface_name)s interface "
                   "of type %(interface_type)s.",
                   {'interface_name': dev,
                    'interface_type': interface_type})
 
 
+@privsep.vif_plug.entrypoint
 def _set_device_mtu(dev, mtu):
     """Set the device MTU."""
     processutils.execute('ip', 'link', 'set', dev, 'mtu', mtu,
                          check_exit_code=[0, 2, 254])
+
+
+@privsep.vif_plug.entrypoint
+def _set_mtu_request(dev, mtu, timeout=None):
+    args = ['--', 'set', 'interface', dev,
+            'mtu_request=%s' % mtu]
+    _ovs_vsctl(args, timeout=timeout)
+
+
+@privsep.vif_plug.entrypoint
+def _ovs_supports_mtu_requests(timeout=None):
+    args = ['--columns=mtu_request', 'list', 'interface']
+    _, error = _ovs_vsctl(args, timeout=timeout)
+    if (error == 'ovs-vsctl: Interface does not contain' +
+              ' a column whose name matches "mtu_request"'):
+            return False
+    return True

vif_plug_ovs/tests/test_linux_net.py

@@ -157,11 +157,14 @@ def test_create_ovs_bridge_cmd(self):
         actual = linux_net._create_ovs_bridge_cmd(bridge, dp_type)
         self.assertEqual(expected, actual)
 
+    @mock.patch.object(linux_net, '_ovs_supports_mtu_requests')
     @mock.patch.object(linux_net, '_ovs_vsctl')
     @mock.patch.object(linux_net, '_create_ovs_vif_cmd')
     @mock.patch.object(linux_net, '_set_device_mtu')
     def test_ovs_vif_port_with_type_vhostuser(self, mock_set_device_mtu,
-                                              mock_create_cmd, mock_vsctl):
+                                              mock_create_cmd, mock_vsctl,
+                                              mock_ovs_supports_mtu_requests):
+        mock_ovs_supports_mtu_requests.return_value = True
         linux_net.create_ovs_vif_port(
             'fake-bridge',
             'fake-dev', 'fake-iface-id', 'fake-mac',
@@ -174,11 +177,14 @@ def test_ovs_vif_port_with_type_vhostuser(self, mock_set_device_mtu,
         self.assertFalse(mock_set_device_mtu.called)
         self.assertTrue(mock_vsctl.called)
 
+    @mock.patch.object(linux_net, '_ovs_supports_mtu_requests')
     @mock.patch.object(linux_net, '_ovs_vsctl')
     @mock.patch.object(linux_net, '_create_ovs_vif_cmd')
     @mock.patch.object(linux_net, '_set_device_mtu')
     def test_ovs_vif_port_with_type_vhostuserclient(self,
-        mock_set_device_mtu, mock_create_cmd, mock_vsctl):
+        mock_set_device_mtu, mock_create_cmd,
+        mock_vsctl, mock_ovs_supports_mtu_requests):
+        mock_ovs_supports_mtu_requests.return_value = True
         linux_net.create_ovs_vif_port(
             'fake-bridge',
             'fake-dev', 'fake-iface-id', 'fake-mac',
@@ -193,11 +199,14 @@ def test_ovs_vif_port_with_type_vhostuserclient(self,
         self.assertFalse(mock_set_device_mtu.called)
         self.assertTrue(mock_vsctl.called)
 
+    @mock.patch.object(linux_net, '_ovs_supports_mtu_requests')
     @mock.patch.object(linux_net, '_ovs_vsctl')
     @mock.patch.object(linux_net, '_create_ovs_vif_cmd')
     @mock.patch.object(linux_net, '_set_device_mtu')
     def test_ovs_vif_port_with_no_mtu(self, mock_set_device_mtu,
-                                      mock_create_cmd, mock_vsctl):
+                                      mock_create_cmd, mock_vsctl,
+                                      mock_ovs_supports_mtu_requests):
+        mock_ovs_supports_mtu_requests.return_value = True
         linux_net.create_ovs_vif_port(
             'fake-bridge',
             'fake-dev', 'fake-iface-id', 'fake-mac',
@@ -208,12 +217,18 @@ def test_ovs_vif_port_with_no_mtu(self, mock_set_device_mtu,
         self.assertFalse(mock_set_device_mtu.called)
         self.assertTrue(mock_vsctl.called)
 
+    @mock.patch.object(linux_net, '_ovs_supports_mtu_requests')
+    @mock.patch.object(linux_net, '_set_mtu_request')
     @mock.patch.object(linux_net, '_ovs_vsctl')
     @mock.patch.object(linux_net, '_create_ovs_vif_cmd',
                        return_value='ovs_command')
     @mock.patch.object(linux_net, '_set_device_mtu')
     def test_ovs_vif_port_with_timeout(self, mock_set_device_mtu,
-                                      mock_create_cmd, mock_vsctl):
+                                       mock_create_cmd, mock_vsctl,
+                                       mock_set_mtu_request,
+                                       mock_ovs_supports_mtu_requests):
+        mock_ovs_supports_mtu_requests.return_value = True
+
         linux_net.create_ovs_vif_port(
             'fake-bridge',
             'fake-dev', 'fake-iface-id', 'fake-mac',
@@ -222,12 +237,17 @@ def test_ovs_vif_port_with_timeout(self, mock_set_device_mtu,
         self.assertFalse(mock_set_device_mtu.called)
         mock_vsctl.assert_called_with('ovs_command', timeout=42)
 
+    @mock.patch.object(linux_net, '_ovs_supports_mtu_requests')
+    @mock.patch.object(linux_net, '_set_mtu_request')
     @mock.patch.object(linux_net, '_ovs_vsctl')
     @mock.patch.object(linux_net, '_create_ovs_vif_cmd',
                        return_value='ovs_command')
     @mock.patch.object(linux_net, '_set_device_mtu')
     def test_ovs_vif_port_with_no_timeout(self, mock_set_device_mtu,
-                                      mock_create_cmd, mock_vsctl):
+                                          mock_create_cmd, mock_vsctl,
+                                          mock_set_mtu_request,
+                                          mock_ovs_supports_mtu_requests):
+        mock_ovs_supports_mtu_requests.return_value = True
         linux_net.create_ovs_vif_port(
             'fake-bridge',
             'fake-dev', 'fake-iface-id', 'fake-mac',
@@ -246,3 +266,30 @@ def test_ovs_vsctl(self, mock_execute):
             [mock.call('ovs-vsctl', *args),
              mock.call('ovs-vsctl', '--timeout=%s' % timeout, *args)],
             mock_execute.mock_calls)
+
+    @mock.patch.object(linux_net, '_ovs_vsctl')
+    def test_set_mtu_request(self, mock_vsctl):
+        dev = 'fake-dev'
+        mtu = 'fake-mtu'
+        timeout = 120
+        linux_net._set_mtu_request(dev, mtu, timeout=timeout)
+        args = ['--', 'set', 'interface', dev,
+                'mtu_request=%s' % mtu]
+        mock_vsctl.assert_called_with(args, timeout=timeout)
+
+    @mock.patch.object(linux_net, '_ovs_vsctl')
+    def test_ovs_supports_mtu_requests(self, mock_vsctl):
+        args = ['--columns=mtu_request', 'list', 'interface']
+        timeout = 120
+        msg = 'ovs-vsctl: Interface does not contain' + \
+              ' a column whose name matches "mtu_request"'
+
+        mock_vsctl.return_value = (None, msg)
+        result = linux_net._ovs_supports_mtu_requests(timeout=timeout)
+        mock_vsctl.assert_called_with(args, timeout=timeout)
+        self.assertFalse(result)
+
+        mock_vsctl.return_value = (None, None)
+        result = linux_net._ovs_supports_mtu_requests(timeout=timeout)
+        mock_vsctl.assert_called_with(args, timeout=timeout)
+        self.assertTrue(result)