Tool to add, configure and remove Windows loopback adapters.

New dependency: wmi (not added to requirements.txt).

Usage (must be running with admin rights):
gns3loopback.exe --add MY_LOOPBACK 10.0.0.1 255.0.0.0
gns3loopback.exe --remove MY_LOOPBACK

gns3server/utils/windows_loopback.py

@@ -0,0 +1,137 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2016 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import sys
+import os
+import argparse
+import shutil
+import ipaddress
+
+if sys.platform.startswith("win"):
+    import wmi
+else:
+    raise SystemExit("This script must run on Windows!")
+
+
+def parse_add_loopback():
+    """
+    Validate params when adding a loopback adapter
+    """
+
+    class Add(argparse.Action):
+
+        def __call__(self, parser, args, values, option_string=None):
+            try:
+                ipaddress.IPv4Interface("{}/{}".format(values[1], values[2]))
+            except ipaddress.AddressValueError as e:
+                raise argparse.ArgumentTypeError("Invalid IP address: {}".format(e))
+            except ipaddress.NetmaskValueError as e:
+                raise argparse.ArgumentTypeError("Invalid subnet mask: {}".format(e))
+            setattr(args, self.dest, values)
+    return Add
+
+
+def add_loopback(devcon_path, name, ip_address, netmask):
+
+    # save the list of network adapter in order to find the one we are about to add
+    previous_adapters = wmi.WMI().Win32_NetworkAdapter()
+    for adapter in previous_adapters:
+        if "Loopback" in adapter.Description and adapter.NetConnectionID == name:
+            raise SystemExit('Windows loopback adapter named "{}" already exists'.format(name))
+
+    # install a new Windows loopback adapter
+    os.system('"{}" install {}\\inf\\netloop.inf *MSLOOP'.format(devcon_path, os.path.expandvars("%WINDIR%")))
+
+    # configure the new Windows loopback adapter
+    for adapter in wmi.WMI().Win32_NetworkAdapter():
+        if "Loopback" in adapter.Description and adapter not in previous_adapters:
+            print('Renaming loopback adapter "{}" to "{}"'.format(adapter.NetConnectionID, name))
+            adapter.NetConnectionID = name
+            for network_config in wmi.WMI().Win32_NetworkAdapterConfiguration(IPEnabled=True):
+                if network_config.InterfaceIndex == adapter.InterfaceIndex:
+                    print('Configuring loopback adapter "{}" with {} {}'.format(name, ip_address, netmask))
+                    retcode = network_config.EnableStatic(IPAddress=[ip_address], SubnetMask=[netmask])[0]
+                    if retcode == 1:
+                        print("A reboot is required")
+                    elif retcode != 0:
+                        print('Error while configuring IP/Subnet mask on "{}"')
+
+                    #FIXME: support gateway?
+                    #network_config.SetGateways(DefaultIPGateway=[""])
+            break
+
+    # restart winpcap/npcap services to take the new adapter into account
+    os.system("net stop npf")
+    os.system("net start npf")
+    os.system("net stop npcap")
+    os.system("net start npcap")
+
+
+def remove_loopback(devcon_path, name):
+
+    deleted = False
+    for adapter in wmi.WMI().Win32_NetworkAdapter():
+        if "Loopback" in adapter.Description and adapter.NetConnectionID == name:
+            # remove a Windows loopback adapter
+            print('Removing loopback adapter "{}"'.format(name))
+            os.system('"{}" remove @{}'.format(devcon_path, adapter.PNPDeviceID))
+            deleted = True
+
+    if not deleted:
+        raise SystemExit('Could not find adapter "{}"'.format(name))
+
+    # update winpcap/npcap services
+    os.system("net stop npf")
+    os.system("net start npf")
+    os.system("net stop npcap")
+    os.system("net start npcap")
+
+
+def main():
+    """
+    Entry point for the Windows loopback tool.
+    """
+
+    parser = argparse.ArgumentParser(description='%(prog)s add/remove Windows loopback adapters')
+    parser.add_argument('-a', "--add", nargs=3, action=parse_add_loopback(), help="add a Windows loopback adapter")
+    parser.add_argument("-r", "--remove", action="store", help="remove a Windows loopback adapter")
+    try:
+        args = parser.parse_args()
+    except argparse.ArgumentTypeError as e:
+        raise SystemExit(e)
+
+    # devcon is required to install/remove Windows loopback adapters
+    devcon_path = shutil.which("devcon")
+    if not devcon_path:
+        raise SystemExit("Could not find devcon.exe")
+
+    from win32com.shell import shell
+    if not shell.IsUserAnAdmin():
+        raise SystemExit("You must run this script as an administrator")
+
+    try:
+        if args.add:
+            add_loopback(devcon_path, args.add[0], args.add[1], args.add[2])
+        if args.remove:
+            remove_loopback(devcon_path, args.remove)
+    except SystemExit as e:
+        print(e)
+        os.system("pause")
+
+if __name__ == '__main__':
+    main()

setup.py

@@ -54,6 +54,7 @@ setup(
         "console_scripts": [
             "gns3server = gns3server.main:main",
             "gns3vmnet = gns3server.utils.vmnet:main",
+            "gns3loopback = gns3server.utils.windows_loopback:main"
         ]
     },
     packages=find_packages(".", exclude=["docs", "tests"]),