Adds Windows MTU plugin

cloudbaseinit/osutils/windows.py

@@ -474,11 +474,7 @@ class WindowsUtils(base.BaseOSUtils):
         return dhcp_hosts
 
     def set_ntp_client_config(self, ntp_host):
-        if self.check_sysnative_dir_exists():
-            base_dir = self.get_sysnative_dir()
-        else:
-            base_dir = self.get_system32_dir()
-
+        base_dir = self._get_system_dir()
         w32tm_path = os.path.join(base_dir, "w32tm.exe")
 
         args = [w32tm_path, '/config', '/manualpeerlist:%s' % ntp_host,
@@ -490,6 +486,38 @@ class WindowsUtils(base.BaseOSUtils):
                             'Output: %(out)s\nError: %(err)s' %
                             {'out': out, 'err': err})
 
+    def set_network_adapter_mtu(self, mac_address, mtu):
+        if not self.check_os_version(6, 0):
+            raise Exception('Setting the MTU is currently not supported on '
+                            'Windows XP and Windows Server 2003')
+
+        conn = wmi.WMI(moniker='//./root/cimv2')
+        net_cfg_list = conn.Win32_NetworkAdapterConfiguration(
+            MACAddress=mac_address)
+
+        if not net_cfg_list:
+            raise Exception('Network interface with MAC address "%s" '
+                            'not found' % mac_address)
+        else:
+            net_cfg = net_cfg_list[0]
+
+            LOG.debug('Setting MTU for interface "%(mac_address)s" with '
+                      'value "%(mtu)s"' %
+                      {'mac_address': mac_address, 'mtu': mtu})
+
+            base_dir = self._get_system_dir()
+            netsh_path = os.path.join(base_dir, 'netsh.exe')
+
+            args = [netsh_path, "interface", "ipv4", "set", "subinterface",
+                    str(net_cfg.InterfaceIndex), "mtu=%s" % mtu,
+                    "store=persistent"]
+            (out, err, ret_val) = self.execute_process(args, False)
+            if ret_val:
+                raise Exception('Setting MTU for interface '
+                                '"%(mac_address)s" with '
+                                'value "%(mtu)s" failed' %
+                                {'mac_address': mac_address, 'mtu': mtu})
+
     def set_static_network_config(self, adapter_name, address, netmask,
                                   broadcast, gateway, dnsnameservers):
         conn = wmi.WMI(moniker='//./root/cimv2')
@@ -901,12 +929,14 @@ class WindowsUtils(base.BaseOSUtils):
                         'you have KB942589 installed')
         return sysnative_dir_exists
 
-    def execute_powershell_script(self, script_path, sysnative=True):
+    def _get_system_dir(self, sysnative=True):
         if sysnative and self.check_sysnative_dir_exists():
-            base_dir = self.get_sysnative_dir()
+            return self.get_sysnative_dir()
         else:
-            base_dir = self.get_system32_dir()
+            return self.get_system32_dir()
 
+    def execute_powershell_script(self, script_path, sysnative=True):
+        base_dir = self._get_system_dir(sysnative)
         powershell_path = os.path.join(base_dir,
                                        'WindowsPowerShell\\v1.0\\'
                                        'powershell.exe')

cloudbaseinit/plugins/factory.py

@@ -22,6 +22,7 @@ opts = [
     cfg.ListOpt(
         'plugins',
         default=[
+            'cloudbaseinit.plugins.windows.mtu.MTUPlugin',
             'cloudbaseinit.plugins.windows.ntpclient.NTPClientPlugin',
             'cloudbaseinit.plugins.windows.sethostname.SetHostNamePlugin',
             'cloudbaseinit.plugins.windows.createuser.CreateUserPlugin',

cloudbaseinit/plugins/windows/mtu.py

@@ -0,0 +1,55 @@
+# Copyright 2014 Cloudbase Solutions Srl
+#
+#    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.
+
+import struct
+
+from oslo.config import cfg
+
+from cloudbaseinit.openstack.common import log as logging
+from cloudbaseinit.osutils import factory as osutils_factory
+from cloudbaseinit.plugins import base
+from cloudbaseinit.utils import dhcp
+
+opts = [
+    cfg.BoolOpt('mtu_use_dhcp_config', default=True,
+                help='Configures the network interfaces MTU based on the '
+                     'values provided via DHCP'),
+]
+
+CONF = cfg.CONF
+CONF.register_opts(opts)
+
+LOG = logging.getLogger(__name__)
+
+
+class MTUPlugin(base.BasePlugin):
+
+    def execute(self, service, shared_data):
+        if CONF.mtu_use_dhcp_config:
+            osutils = osutils_factory.get_os_utils()
+            dhcp_hosts = osutils.get_dhcp_hosts_in_use()
+
+            for (mac_address, dhcp_host) in dhcp_hosts:
+                options_data = dhcp.get_dhcp_options(dhcp_host,
+                                                     [dhcp.OPTION_MTU])
+                if options_data:
+                    mtu_option_data = options_data.get(dhcp.OPTION_MTU)
+                    if mtu_option_data:
+                        mtu = struct.unpack('!H', mtu_option_data)[0]
+                        osutils.set_network_adapter_mtu(mac_address, mtu)
+                    else:
+                        LOG.debug('Could not obtain the MTU configuration '
+                                  'via DHCP for interface "%s"' % mac_address)
+
+        return (base.PLUGIN_EXECUTE_ON_NEXT_BOOT, False)

cloudbaseinit/utils/dhcp.py

@@ -21,6 +21,7 @@ import struct
 _DHCP_COOKIE = b'\x63\x82\x53\x63'
 _OPTION_END = b'\xff'
 
+OPTION_MTU = 26
 OPTION_NTP_SERVERS = 42