Check whether tun2socks supports fakeDNS

Netch/Controllers/Mode/TUNTAPController.cs

@@ -237,7 +237,7 @@ namespace Netch.Controllers
             argument.Append(
                 $"-tunAddr {Global.Settings.TUNTAP.Address} -tunMask {Global.Settings.TUNTAP.Netmask} -tunGw {Global.Settings.TUNTAP.Gateway} -tunDns {dns} -tunName \"{adapterName}\" ");
 
-            if (Global.Settings.TUNTAP.UseFakeDNS)
+            if (Global.Settings.TUNTAP.UseFakeDNS && Global.SupportFakeDns)
                 argument.Append("-fakeDns ");
 
             return StartInstanceAuto(argument.ToString(), ProcessPriorityClass.RealTime);
@@ -257,6 +257,40 @@ namespace Netch.Controllers
             Task.WaitAll(tasks);
         }
 
+        public bool TestFakeDNS()
+        {
+            var exited = false;
+            var helpStr = new StringBuilder();
+            try
+            {
+                void OnOutputDataReceived(object sender,DataReceivedEventArgs e)
+                {
+                    if (e.Data == null)
+                    {
+                        exited = true;
+                        return;
+                    }
+                    helpStr.Append(e.Data);
+                }
+                InitInstance("-h");
+                // Instance.OutputDataReceived += OnOutputDataReceived;
+                Instance.ErrorDataReceived += OnOutputDataReceived;
+                Instance.Start();
+                Instance.BeginOutputReadLine();
+                Instance.BeginErrorReadLine();
+                while (!exited)
+                {
+                    Thread.Sleep(200);
+                }
+
+                return helpStr.ToString().Contains("-fakeDns");
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
         /// <summary>
         ///     搜索出口和TUNTAP适配器
         /// </summary>

Netch/Forms/SettingForm.Designer.cs

@@ -184,6 +184,7 @@
             this.UseFakeDNSCheckBox.Size = new System.Drawing.Size(110, 21);
             this.UseFakeDNSCheckBox.TabIndex = 11;
             this.UseFakeDNSCheckBox.Text = "Use Fake DNS";
+            this.UseFakeDNSCheckBox.Visible = false;
             this.UseFakeDNSCheckBox.UseVisualStyleBackColor = true;
             // 
             // ProxyDNSCheckBox

Netch/Forms/SettingForm.cs

@@ -122,6 +122,7 @@ namespace Netch.Forms
 
         private void SettingForm_Load(object sender, EventArgs e)
         {
+            UseFakeDNSCheckBox.Visible = Global.SupportFakeDns;
             InitText();
             InitValue();
         }

Netch/Global.cs

@@ -24,6 +24,8 @@ namespace Netch
         /// </summary>
         public static MainForm MainForm;
 
+        public static bool SupportFakeDns = false;
+
         /// <summary>
 		///		SS/SSR 加密方式
 		/// </summary>

Netch/Netch.cs

@@ -67,9 +67,16 @@ namespace Netch
                 }
 
                 Logging.Info($"版本: {UpdateChecker.Owner}/{UpdateChecker.Repo}@{UpdateChecker.Version}");
-                Task.Run(() => { Logging.Info($"主程序 SHA256: {Utils.Utils.SHA256CheckSum(Application.ExecutablePath)}"); });
-                Logging.Info("启动单实例");
-                Task.Run(OnlyInstance.Server);
+                Task.Run(() =>
+                {
+                    Logging.Info($"主程序 SHA256: {Utils.Utils.SHA256CheckSum(Application.ExecutablePath)}");
+                });
+                Task.Run(() =>
+                {
+                    Logging.Info("启动单实例");
+                    OnlyInstance.Server();
+                });
+                Task.Run(() => { Global.SupportFakeDns = new TUNTAPController().TestFakeDNS(); });
 
                 // 绑定错误捕获
                 Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);