Use wininet API to setup system proxy

Get rid of tricky registry handling

Several files come from https://code.msdn.microsoft.com/windowsapps/CSWebBrowserWithProxy-c8535715/view/SourceCode

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

shadowsocks-csharp/Controller/System/SystemProxy.cs

@@ -1,34 +1,11 @@
-using System.Windows.Forms;
-using Microsoft.Win32;
-using System;
-using System.Runtime.InteropServices;
-using System.IO;
+using System;
 using Shadowsocks.Model;
-using Shadowsocks.Util;
+using Shadowsocks.Util.SystemProxy;
 
 namespace Shadowsocks.Controller
 {
     public static class SystemProxy
     {
-
-        [DllImport("wininet.dll")]
-        public static extern bool InternetSetOption(IntPtr hInternet, int dwOption, IntPtr lpBuffer, int dwBufferLength);
-        public const int INTERNET_OPTION_SETTINGS_CHANGED = 39;
-        public const int INTERNET_OPTION_REFRESH = 37;
-        static bool _settingsReturn, _refreshReturn;
-
-        public static void NotifyIE()
-        {
-            // These lines implement the Interface in the beginning of program 
-            // They cause the OS to refresh the settings, causing IP to realy update
-            _settingsReturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_SETTINGS_CHANGED, IntPtr.Zero, 0);
-            _refreshReturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_REFRESH, IntPtr.Zero, 0);
-        }
-
-        private static readonly DateTime UnixEpoch
-            = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
-        public static long ToUnixEpochMilliseconds(this DateTime dt)
-            => (long)(dt - UnixEpoch).TotalMilliseconds;
         private static string GetTimestamp(DateTime value)
         {
             return value.ToString("yyyyMMddHHmmssfff");
@@ -43,139 +20,27 @@ namespace Shadowsocks.Controller
             {
                 enabled = false;
             }
-            RegistryKey registry = null;
-            try {
-                registry = Utils.OpenUserRegKey( @"Software\Microsoft\Windows\CurrentVersion\Internet Settings", true );
-                if ( registry == null ) {
-                    Logging.Error( @"Cannot find HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings" );
-                    return;
-                }
-                if ( enabled ) {
-                    if ( global ) {
-                        registry.SetValue( "ProxyEnable", 1 );
-                        registry.SetValue( "ProxyServer", "127.0.0.1:" + config.localPort.ToString() );
-                        registry.SetValue( "AutoConfigURL", "" );
-                    } else {
-                        string pacUrl;
-                        if ( config.useOnlinePac && ! config.pacUrl.IsNullOrEmpty() )
-                            pacUrl = config.pacUrl;
-                        else
-                            pacUrl = $"http://127.0.0.1:{config.localPort}/pac?t={GetTimestamp( DateTime.Now )}";
-                        registry.SetValue( "ProxyEnable", 0 );
-                        var readProxyServer = registry.GetValue( "ProxyServer" );
-                        registry.SetValue( "ProxyServer", "" );
-                        registry.SetValue( "AutoConfigURL", pacUrl );
-                    }
-                } else {
-                    registry.SetValue( "ProxyEnable", 0 );
-                    registry.SetValue( "ProxyServer", "" );
-                    registry.SetValue( "AutoConfigURL", "" );
-                }
-
-                //Set AutoDetectProxy
-                IEAutoDetectProxy( ! enabled );
 
-                NotifyIE();
-                //Must Notify IE first, or the connections do not chanage
-                CopyProxySettingFromLan();
-            } catch ( Exception e ) {
-                Logging.LogUsefulException( e );
-                // TODO this should be moved into views
-                MessageBox.Show( I18N.GetString( "Failed to update registry" ) );
-            } finally {
-                if ( registry != null ) {
-                    try {
-                        registry.Close();
-                        registry.Dispose();
-                    } catch (Exception e)
-                    { Logging.LogUsefulException(e); }
-                }
-            }
-        }
-
-        private static void CopyProxySettingFromLan()
-        {
-            RegistryKey registry = null;
-            try {
-                registry = Utils.OpenUserRegKey( @"Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections", true );
-                if ( registry == null ) {
-                    Logging.Error( @"Cannot find HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections" );
-                    return;
-                }
-                var defaultValue = registry.GetValue( "DefaultConnectionSettings" );
-                var connections = registry.GetValueNames();
-                foreach ( var each in connections ) {
-                    switch ( each.ToUpperInvariant() ) {
-                        case "DEFAULTCONNECTIONSETTINGS":
-                        case "LAN CONNECTION":
-                        case "SAVEDLEGACYSETTINGS":
-                            continue;
-                        default:
-                            //set all the connections's proxy as the lan
-                            registry.SetValue( each, defaultValue );
-                            continue;
-                    }
-                }
-                NotifyIE();
-            } catch ( IOException e ) {
-                Logging.LogUsefulException( e );
-            } finally {
-                if ( registry != null ) {
-                    try {
-                        registry.Close();
-                        registry.Dispose();
-                    } catch (Exception e)
-                    { Logging.LogUsefulException(e); }
-                }
-            }
-        }
-
-        /// <summary>
-        /// Checks or unchecks the IE Options Connection setting of "Automatically detect Proxy"
-        /// </summary>
-        /// <param name="set">Provide 'true' if you want to check the 'Automatically detect Proxy' check box. To uncheck, pass 'false'</param>
-        private static void IEAutoDetectProxy(bool set)
-        {
-            RegistryKey registry = null;
-            try {
-                registry = Utils.OpenUserRegKey( @"Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections", true );
-                if ( registry == null ) {
-                    Logging.Error( @"Cannot find HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections" );
-                    return;
-                }
-                var defConnection = ( byte[] ) registry.GetValue( "DefaultConnectionSettings" );
-                var savedLegacySetting = ( byte[] ) registry.GetValue( "SavedLegacySettings" );
-
-                const int versionOffset = 4;
-                const int optionsOffset = 8;
-
-                if ( set ) {
-                    defConnection[ optionsOffset ] = ( byte ) ( defConnection[ optionsOffset ] | 8 );
-                    savedLegacySetting[ optionsOffset ] = ( byte ) ( savedLegacySetting[ optionsOffset ] | 8 );
-                } else {
-                    defConnection[ optionsOffset ] = ( byte ) ( defConnection[ optionsOffset ] & ~8 );
-                    savedLegacySetting[ optionsOffset ] = ( byte ) ( savedLegacySetting[ optionsOffset ] & ~8 );
+            if (enabled)
+            {
+                if (global)
+                {
+                    WinINet.SetIEProxy(true, true, "127.0.0.1:" + config.localPort.ToString(), "");
                 }
-
-                BitConverter.GetBytes(unchecked( BitConverter.ToUInt32( defConnection, versionOffset ) + 1 ) )
-                            .CopyTo( defConnection, versionOffset );
-                BitConverter.GetBytes(unchecked( BitConverter.ToUInt32( savedLegacySetting, versionOffset ) + 1 ) )
-                            .CopyTo( savedLegacySetting, versionOffset );
-
-                registry.SetValue( "DefaultConnectionSettings", defConnection );
-                registry.SetValue( "SavedLegacySettings", savedLegacySetting );
-            } catch ( Exception e ) {
-                Logging.LogUsefulException( e );
-            } finally {
-                if (registry != null)
+                else
                 {
-                    try {
-                        registry.Close();
-                        registry.Dispose();
-                    } catch (Exception e)
-                    { Logging.LogUsefulException(e); }
+                    string pacUrl;
+                    if (config.useOnlinePac && !config.pacUrl.IsNullOrEmpty())
+                        pacUrl = config.pacUrl;
+                    else
+                        pacUrl = $"http://127.0.0.1:{config.localPort}/pac?t={GetTimestamp(DateTime.Now)}";
+                    WinINet.SetIEProxy(true, false, "", pacUrl);
                 }
             }
+            else
+            {
+                WinINet.SetIEProxy(false, false, "", "");
+            }
         }
     }
-}
+}

shadowsocks-csharp/Util/SystemProxy/INTERNET_OPTION.cs

@@ -0,0 +1,36 @@
+/****************************** Module Header ******************************\
+ Module Name:  INTERNET_OPTION.cs
+ Project:      CSWebBrowserWithProxy
+ Copyright (c) Microsoft Corporation.
+ 
+ This enum contains 4 WinINet constants used in method InternetQueryOption and 
+ InternetSetOption functions. 
+ Visit http://msdn.microsoft.com/en-us/library/aa385328(VS.85).aspx to get the 
+ whole constants list.
+ 
+ This source is subject to the Microsoft Public License.
+ See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
+ All other rights reserved.
+ 
+ THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
+ EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
+ WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+\***************************************************************************/
+
+namespace Shadowsocks.Util.SystemProxy
+{
+    public enum INTERNET_OPTION
+    {
+        // Sets or retrieves an INTERNET_PER_CONN_OPTION_LIST structure that specifies
+        // a list of options for a particular connection.
+        INTERNET_OPTION_PER_CONNECTION_OPTION = 75,
+
+        // Notify the system that the registry settings have been changed so that
+        // it verifies the settings on the next call to InternetConnect.
+        INTERNET_OPTION_SETTINGS_CHANGED = 39,
+
+        // Causes the proxy data to be reread from the registry for a handle.
+        INTERNET_OPTION_REFRESH = 37
+
+    }
+}

shadowsocks-csharp/Util/SystemProxy/INTERNET_PER_CONN_OPTION.cs

@@ -0,0 +1,97 @@
+/****************************** Module Header ******************************\
+ Module Name:  INTERNET_PER_CONN_OPTION.cs
+ Project:      CSWebBrowserWithProxy
+ Copyright (c) Microsoft Corporation.
+ 
+ This file defines the struct INTERNET_PER_CONN_OPTION and constants used by it.
+ The struct INTERNET_PER_CONN_OPTION contains the value of an option that to be 
+ set to internet settings.
+ Visit http://msdn.microsoft.com/en-us/library/aa385145(VS.85).aspx to get the 
+ detailed description.
+ 
+ This source is subject to the Microsoft Public License.
+ See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
+ All other rights reserved.
+ 
+ THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
+ EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
+ WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+\***************************************************************************/
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Shadowsocks.Util.SystemProxy
+{
+    /// <summary>
+    /// Constants used in INTERNET_PER_CONN_OPTION_OptionUnion struct.
+    /// </summary>
+    public enum INTERNET_PER_CONN_OptionEnum
+    {
+        INTERNET_PER_CONN_FLAGS = 1,
+        INTERNET_PER_CONN_PROXY_SERVER = 2,
+        INTERNET_PER_CONN_PROXY_BYPASS = 3,
+        INTERNET_PER_CONN_AUTOCONFIG_URL = 4,
+        INTERNET_PER_CONN_AUTODISCOVERY_FLAGS = 5,
+        INTERNET_PER_CONN_AUTOCONFIG_SECONDARY_URL = 6,
+        INTERNET_PER_CONN_AUTOCONFIG_RELOAD_DELAY_MINS = 7,
+        INTERNET_PER_CONN_AUTOCONFIG_LAST_DETECT_TIME = 8,
+        INTERNET_PER_CONN_AUTOCONFIG_LAST_DETECT_URL = 9,
+        INTERNET_PER_CONN_FLAGS_UI = 10
+    }
+
+    /// <summary>
+    /// Constants used in INTERNET_PER_CONN_OPTON struct.
+    /// </summary>
+    [Flags]
+    public enum INTERNET_OPTION_PER_CONN_FLAGS
+    {
+        PROXY_TYPE_DIRECT = 0x00000001,   // direct to net
+        PROXY_TYPE_PROXY = 0x00000002,   // via named proxy
+        PROXY_TYPE_AUTO_PROXY_URL = 0x00000004,   // autoproxy URL
+        PROXY_TYPE_AUTO_DETECT = 0x00000008   // use autoproxy detection
+    }
+
+    /// <summary>
+    /// Constants used in INTERNET_PER_CONN_OPTON struct.
+    /// Windows 7 and later:  
+    /// Clients that support Internet Explorer 8 should query the connection type using INTERNET_PER_CONN_FLAGS_UI.
+    /// If this query fails, then the system is running a previous version of Internet Explorer and the client should
+    /// query again with INTERNET_PER_CONN_FLAGS.
+    /// Restore the connection type using INTERNET_PER_CONN_FLAGS regardless of the version of Internet Explorer.
+    /// XXX: If fails, notify user to upgrade Internet Explorer
+    /// </summary>
+    [Flags]
+    public enum INTERNET_OPTION_PER_CONN_FLAGS_UI
+    {
+        PROXY_TYPE_DIRECT = 0x00000001,   // direct to net
+        PROXY_TYPE_PROXY = 0x00000002,   // via named proxy
+        PROXY_TYPE_AUTO_PROXY_URL = 0x00000004,   // autoproxy URL
+        PROXY_TYPE_AUTO_DETECT = 0x00000008   // use autoproxy detection
+    }
+
+    /// <summary>
+    /// Used in INTERNET_PER_CONN_OPTION.
+    /// When create a instance of OptionUnion, only one filed will be used.
+    /// The StructLayout and FieldOffset attributes could help to decrease the struct size.
+    /// </summary>
+    [StructLayout(LayoutKind.Explicit)]
+    public struct INTERNET_PER_CONN_OPTION_OptionUnion
+    {
+        // A value in INTERNET_OPTION_PER_CONN_FLAGS.
+        [FieldOffset(0)]
+        public int dwValue;
+        [FieldOffset(0)]
+        public System.IntPtr pszValue;
+        [FieldOffset(0)]
+        public System.Runtime.InteropServices.ComTypes.FILETIME ftValue;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    public struct INTERNET_PER_CONN_OPTION
+    {
+        // A value in INTERNET_PER_CONN_OptionEnum.
+        public int dwOption;
+        public INTERNET_PER_CONN_OPTION_OptionUnion Value;
+    }
+}

shadowsocks-csharp/Util/SystemProxy/INTERNET_PER_CONN_OPTION_LIST.cs

@@ -0,0 +1,38 @@
+/****************************** Module Header ******************************\
+ Module Name:  INTERNET_PER_CONN_OPTION_LIST.cs
+ Project:      CSWebBrowserWithProxy
+ Copyright (c) Microsoft Corporation.
+ 
+ The struct INTERNET_PER_CONN_OPTION contains a list of options that to be 
+ set to internet connection.
+ Visit http://msdn.microsoft.com/en-us/library/aa385146(VS.85).aspx to get the 
+ detailed description.
+ 
+ This source is subject to the Microsoft Public License.
+ See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
+ All other rights reserved.
+ 
+ THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
+ EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
+ WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+\***************************************************************************/
+
+using System.Runtime.InteropServices;
+
+namespace Shadowsocks.Util.SystemProxy
+{
+    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
+    public struct INTERNET_PER_CONN_OPTION_LIST
+    {
+        public int Size;
+
+        // The connection to be set. NULL means LAN.
+        public System.IntPtr Connection;
+        
+        public int OptionCount;
+        public int OptionError;
+
+        // List of INTERNET_PER_CONN_OPTIONs.
+        public System.IntPtr pOptions;
+    }
+}

shadowsocks-csharp/Util/SystemProxy/NativeMethods.cs

@@ -0,0 +1,36 @@
+/****************************** Module Header ******************************\
+ Module Name:  NativeMethods.cs
+ Project:      CSWebBrowserWithProxy
+ Copyright (c) Microsoft Corporation.
+ 
+ This class is a simple .NET wrapper of wininet.dll. It contains 4 extern
+ methods in wininet.dll. They are InternetOpen, InternetCloseHandle, 
+ InternetSetOption and InternetQueryOption.
+ 
+ This source is subject to the Microsoft Public License.
+ See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
+ All other rights reserved.
+ 
+ THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
+ EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
+ WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+\***************************************************************************/
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Shadowsocks.Util.SystemProxy
+{
+    internal static class NativeMethods
+    {
+        /// <summary>
+        /// Sets an Internet option.
+        /// </summary>
+        [DllImport("wininet.dll", CharSet = CharSet.Ansi, SetLastError = true)]
+        internal static extern bool InternetSetOption(
+            IntPtr hInternet,
+            INTERNET_OPTION dwOption,
+            IntPtr lpBuffer,
+            int lpdwBufferLength);
+    }
+}

shadowsocks-csharp/Util/SystemProxy/WinINet.cs

@@ -0,0 +1,152 @@
+/****************************** Module Header ******************************\
+ Module Name:  WinINet.cs
+ Project:      CSWebBrowserWithProxy
+ Copyright (c) Microsoft Corporation.
+ 
+ This class is used to set the proxy. or restore to the system proxy for the
+ current application
+ 
+ This source is subject to the Microsoft Public License.
+ See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
+ All other rights reserved.
+ 
+ THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 
+ EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED 
+ WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
+\***************************************************************************/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+
+namespace Shadowsocks.Util.SystemProxy
+{
+    public static class WinINet
+    {
+        /// <summary>
+        /// Set IE settings for LAN connection.
+        /// </summary>
+        public static void SetIEProxy(bool enable, bool global, string proxyServer, string pacURL)
+        {
+            List<INTERNET_PER_CONN_OPTION> _optionlist = new List<INTERNET_PER_CONN_OPTION>();
+            if (enable)
+            {
+                if (global)
+                {
+                    // global proxy
+                    _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                    {
+                        dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_FLAGS_UI,
+                        Value = { dwValue = (int)INTERNET_OPTION_PER_CONN_FLAGS_UI.PROXY_TYPE_PROXY }
+                    });
+                    _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                    {
+                        dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_SERVER,
+                        Value = { pszValue = Marshal.StringToHGlobalAnsi(proxyServer) }
+                    });
+                    _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                    {
+                        dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_BYPASS,
+                        Value = { pszValue = Marshal.StringToHGlobalAnsi("<local>") }
+                    });
+                }
+                else
+                {
+                    // pac
+                    _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                    {
+                        dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_FLAGS_UI,
+                        Value = { dwValue = (int)INTERNET_OPTION_PER_CONN_FLAGS_UI.PROXY_TYPE_AUTO_PROXY_URL }
+                    });
+                    _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                    {
+                        dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_AUTOCONFIG_URL,
+                        Value = { pszValue = Marshal.StringToHGlobalAnsi(pacURL) }
+                    });
+                }
+            }
+            else
+            {
+                // direct
+                _optionlist.Add(new INTERNET_PER_CONN_OPTION
+                {
+                    dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_FLAGS_UI,
+                    Value = { dwValue = (int)(INTERNET_OPTION_PER_CONN_FLAGS_UI.PROXY_TYPE_AUTO_DETECT
+                                            | INTERNET_OPTION_PER_CONN_FLAGS_UI.PROXY_TYPE_DIRECT) }
+                });
+            }
+
+            // Get total length of INTERNET_PER_CONN_OPTIONs
+            var len = _optionlist.Sum(each => Marshal.SizeOf(each));
+
+            // Allocate a block of memory of the options.
+            IntPtr buffer = Marshal.AllocCoTaskMem(len);
+
+            IntPtr current = buffer;
+
+            // Marshal data from a managed object to an unmanaged block of memory.
+            foreach (INTERNET_PER_CONN_OPTION eachOption in _optionlist)
+            {
+                Marshal.StructureToPtr(eachOption, current, false);
+                current = (IntPtr)((int)current + Marshal.SizeOf(eachOption));
+            }
+
+            // Initialize a INTERNET_PER_CONN_OPTION_LIST instance.
+            INTERNET_PER_CONN_OPTION_LIST optionList = new INTERNET_PER_CONN_OPTION_LIST();
+
+            // Point to the allocated memory.
+            optionList.pOptions = buffer;
+
+            // Return the unmanaged size of an object in bytes.
+            optionList.Size = Marshal.SizeOf(optionList);
+
+            // IntPtr.Zero means LAN connection.
+            optionList.Connection = IntPtr.Zero;
+
+            optionList.OptionCount = _optionlist.Count;
+            optionList.OptionError = 0;
+            int optionListSize = Marshal.SizeOf(optionList);
+
+            // Allocate memory for the INTERNET_PER_CONN_OPTION_LIST instance.
+            IntPtr intptrStruct = Marshal.AllocCoTaskMem(optionListSize);
+
+            // Marshal data from a managed object to an unmanaged block of memory.
+            Marshal.StructureToPtr(optionList, intptrStruct, true);
+
+            // Set internet settings.
+            bool bReturn = NativeMethods.InternetSetOption(
+                IntPtr.Zero, 
+                INTERNET_OPTION.INTERNET_OPTION_PER_CONNECTION_OPTION,
+                intptrStruct, optionListSize);
+
+            // Free the allocated memory.
+            foreach (var v in _optionlist)
+            {
+                // free strings
+                if (v.Value.pszValue != IntPtr.Zero)
+                    Marshal.FreeHGlobal(v.Value.pszValue);
+            }
+            Marshal.FreeCoTaskMem(buffer);
+            Marshal.FreeCoTaskMem(intptrStruct);
+
+            // Throw an exception if this operation failed.
+            if (!bReturn)
+            {
+                throw new Exception("InternetSetOption: " + Marshal.GetLastWin32Error());
+            }
+
+            // Notify the system that the registry settings have been changed and cause
+            // the proxy data to be reread from the registry for a handle.
+            NativeMethods.InternetSetOption(
+                IntPtr.Zero,
+                INTERNET_OPTION.INTERNET_OPTION_SETTINGS_CHANGED,
+                IntPtr.Zero, 0);
+
+            NativeMethods.InternetSetOption(
+                IntPtr.Zero,
+                INTERNET_OPTION.INTERNET_OPTION_REFRESH,
+                IntPtr.Zero, 0);
+        }
+    }
+}

shadowsocks-csharp/Util/Util.cs

@@ -5,6 +5,7 @@ using System.IO;
 using System.IO.Compression;
 using System.Linq;
 using System.Runtime.InteropServices;
+using System.Security;
 using System.Windows.Forms;
 using Microsoft.Win32;
 using Shadowsocks.Controller;
@@ -210,14 +211,34 @@ namespace Shadowsocks.Util
             return new BandwidthScaleInfo(f, unit, scale);
         }
 
-        public static RegistryKey OpenUserRegKey( string name, bool writable ) {
+        public static RegistryKey OpenUserRegKey( string name, bool writable )
+        {
             // we are building x86 binary for both x86 and x64, which will
             // cause problem when opening registry key
             // detect operating system instead of CPU
-            RegistryKey userKey = RegistryKey.OpenRemoteBaseKey( RegistryHive.CurrentUser, "",
-                Environment.Is64BitOperatingSystem ? RegistryView.Registry64 : RegistryView.Registry32 )
-                .OpenSubKey( name, writable );
-            return userKey;
+            if (name.IsNullOrEmpty()) throw new ArgumentException(nameof(name));
+            try
+            {
+                RegistryKey userKey = RegistryKey.OpenBaseKey(RegistryHive.CurrentUser,
+                        Environment.Is64BitOperatingSystem ? RegistryView.Registry64 : RegistryView.Registry32)
+                    .OpenSubKey(name, writable);
+                return userKey;
+            }
+            catch (UnauthorizedAccessException uae)
+            {
+                Logging.LogUsefulException(uae);
+                return null;
+            }
+            catch (SecurityException se)
+            {
+                Logging.LogUsefulException(se);
+                return null;
+            }
+            catch (ArgumentException ae)
+            {
+                MessageBox.Show("OpenUserRegKey: " + ae.ToString());
+                return null;
+            }
         }
 
         public static bool IsWinVistaOrHigher() {

shadowsocks-csharp/shadowsocks-csharp.csproj

@@ -190,6 +190,11 @@
     <Compile Include="Util\Sockets\LineReader.cs" />
     <Compile Include="Util\Sockets\SocketUtil.cs" />
     <Compile Include="Util\Sockets\WrappedSocket.cs" />
+    <Compile Include="Util\SystemProxy\INTERNET_OPTION.cs" />
+    <Compile Include="Util\SystemProxy\INTERNET_PER_CONN_OPTION.cs" />
+    <Compile Include="Util\SystemProxy\INTERNET_PER_CONN_OPTION_LIST.cs" />
+    <Compile Include="Util\SystemProxy\NativeMethods.cs" />
+    <Compile Include="Util\SystemProxy\WinINet.cs" />
     <Compile Include="Util\Util.cs" />
     <Compile Include="View\ConfigForm.cs">
       <SubType>Form</SubType>