windows: network: fix DHCP setting

Fixed Windows osutils DHCP setting, as the former implementation that
used registry keys was no reliable. Using MSFT_NetIPInterface should fix
any reliability issues.

Change-Id: I94cf70b092da706cdfaf57bc78d7b266064b97b0

cloudbaseinit/osutils/windows.py

@@ -912,19 +912,21 @@ class WindowsUtils(base.BaseOSUtils):
         return reboot_required
 
     @staticmethod
-    def _fix_network_adapter_dhcp(interface_name, enable_dhcp, address_family):
-        interface_id = WindowsUtils._get_network_adapter(interface_name).GUID
-        tcpip_key = "Tcpip6" if address_family == AF_INET6 else "Tcpip"
+    def _fix_network_adapter_dhcp(interface_name,
+                                  enable_dhcp,
+                                  address_family):
+        enable_dhcp_value = 1 if enable_dhcp else 0
 
-        with winreg.OpenKey(
-                winreg.HKEY_LOCAL_MACHINE,
-                "SYSTEM\\CurrentControlSet\\services\\%(tcpip_key)s\\"
-                "Parameters\\Interfaces\\%(interface_id)s" %
-                {"tcpip_key": tcpip_key, "interface_id": interface_id},
-                0, winreg.KEY_SET_VALUE) as key:
-            winreg.SetValueEx(
-                key, 'EnableDHCP', 0, winreg.REG_DWORD,
-                1 if enable_dhcp else 0)
+        conn = wmi.WMI(moniker='//./root/standardcimv2')
+        net_interface = conn.MSFT_NetIPInterface(
+            InterfaceAlias=interface_name, AddressFamily=address_family)
+        if not len(net_interface):
+            raise exception.ItemNotFoundException(
+                'Network interface with name "%s" not found' %
+                interface_name)
+        net_interface = net_interface[0]
+        net_interface.Dhcp = enable_dhcp_value
+        net_interface.put()
 
     @staticmethod
     def _set_interface_dns(interface_name, dnsnameservers):

cloudbaseinit/tests/osutils/test_windows.py

@@ -2000,6 +2000,40 @@ class TestWindowsUtils(testutils.CloudbaseInitTestBase):
                            mock.sentinel.mac_address,
                            mock.sentinel.dhcp_server)], response)
 
+    def test_fix_network_adapter_dhcp(self):
+        self._test_fix_network_adapter_dhcp(True)
+
+    def test_fix_network_adapter_dhcp_no_network_adapter(self):
+        self._test_fix_network_adapter_dhcp(False)
+
+    def _test_fix_network_adapter_dhcp(self, no_net_interface_found):
+        mock_interface_name = "eth12"
+        mock_enable_dhcp = True
+        mock_address_family = self.windows_utils.AF_INET
+
+        conn = self._wmi_mock.WMI.return_value
+        existing_net_interface = mock.Mock()
+        existing_net_interface.Dhcp = 0
+
+        if not no_net_interface_found:
+            conn.MSFT_NetIPInterface.return_value = [existing_net_interface]
+
+        if no_net_interface_found:
+            with self.assertRaises(exception.ItemNotFoundException):
+                self._winutils._fix_network_adapter_dhcp(
+                    mock_interface_name, mock_enable_dhcp,
+                    mock_address_family)
+        else:
+            self._winutils._fix_network_adapter_dhcp(
+                mock_interface_name, mock_enable_dhcp,
+                mock_address_family)
+
+            conn.MSFT_NetIPInterface.assert_called_once_with(
+                InterfaceAlias=mock_interface_name,
+                AddressFamily=mock_address_family)
+            self.assertEqual(existing_net_interface.Dhcp, 1)
+            existing_net_interface.put.assert_called_once()
+
     @mock.patch('cloudbaseinit.osutils.windows.WindowsUtils'
                 '.check_sysnative_dir_exists')
     @mock.patch('cloudbaseinit.osutils.windows.WindowsUtils'