tun: dual MTU, gateway, DNS, auto routing

Change TunSettings to support separate IPv4/IPv6 MTU values and add gateway, DNS, autoSystemRoutingTable and autoOutboundsInterface properties. Introduces _normalizeMtu to accept legacy single-value or array forms and provide sensible defaults. Update fromJson/toJson to handle new fields and preserve backward compatibility. Update tun form UI to expose MTU IPv4/IPv6 inputs, Gateway/DNS tag selects, Auto Routing Table and Auto Outbounds input.

web/assets/js/model/inbound.js

@@ -2723,29 +2723,60 @@ Inbound.TunSettings = class extends Inbound.Settings {
     constructor(
         protocol,
         name = 'xray0',
-        mtu = 1500,
-        userLevel = 0
+        mtu = [1500, 1280],
+        gateway = [],
+        dns = [],
+        userLevel = 0,
+        autoSystemRoutingTable = [],
+        autoOutboundsInterface = 'auto'
     ) {
         super(protocol);
         this.name = name;
-        this.mtu = mtu;
+        this.mtu = this._normalizeMtu(mtu);
+        this.gateway = Array.isArray(gateway) ? gateway : [];
+        this.dns = Array.isArray(dns) ? dns : [];
         this.userLevel = userLevel;
+        this.autoSystemRoutingTable = Array.isArray(autoSystemRoutingTable) ? autoSystemRoutingTable : [];
+        this.autoOutboundsInterface = autoOutboundsInterface;
+    }
+
+    _normalizeMtu(mtu) {
+        if (!Array.isArray(mtu)) {
+            const single = Number(mtu) || 1500;
+            return [single, single];
+        }
+        if (mtu.length === 0) {
+            return [1500, 1280];
+        }
+        if (mtu.length === 1) {
+            const single = Number(mtu[0]) || 1500;
+            return [single, single];
+        }
+        return [Number(mtu[0]) || 1500, Number(mtu[1]) || 1280];
     }
 
     static fromJson(json = {}) {
         return new Inbound.TunSettings(
             Protocols.TUN,
             json.name ?? 'xray0',
-            json.mtu ?? json.MTU ?? 1500,
-            json.userLevel ?? 0
+            json.mtu ?? json.MTU ?? [1500, 1280],
+            json.gateway ?? json.Gateway ?? [],
+            json.dns ?? json.DNS ?? [],
+            json.userLevel ?? 0,
+            json.autoSystemRoutingTable ?? [],
+            Object.prototype.hasOwnProperty.call(json, 'autoOutboundsInterface') ? json.autoOutboundsInterface : 'auto'
         );
     }
 
     toJson() {
         return {
             name: this.name || 'xray0',
-            mtu: this.mtu || 1500,
+            mtu: this._normalizeMtu(this.mtu),
+            gateway: this.gateway,
+            dns: this.dns,
             userLevel: this.userLevel || 0,
+            autoSystemRoutingTable: this.autoSystemRoutingTable,
+            autoOutboundsInterface: this.autoOutboundsInterface,
         };
     }
 };

web/html/form/protocol/tun.html

@@ -22,17 +22,43 @@
         <template slot="title">
           <span>{{ i18n "pages.xray.tun.mtuDesc" }}</span>
         </template>
-        MTU
+        MTU IPv4
         <a-icon type="question-circle"></a-icon>
       </a-tooltip>
     </template>
     <a-input-number
-      v-model.number="inbound.settings.mtu"
+      v-model.number="inbound.settings.mtu[0]"
       :min="1"
       :max="9000"
       placeholder="1500"
     ></a-input-number>
   </a-form-item>
+  <a-form-item label="MTU IPv6">
+    <a-input-number
+      v-model.number="inbound.settings.mtu[1]"
+      :min="1"
+      :max="9000"
+      placeholder="1280"
+    ></a-input-number>
+  </a-form-item>
+  <a-form-item label="Gateway">
+    <a-select
+      mode="tags"
+      v-model="inbound.settings.gateway"
+      :style="{ width: '100%' }"
+      :token-separators="[',']"
+      placeholder="IPv4/IPv6 gateway"
+    ></a-select>
+  </a-form-item>
+  <a-form-item label="DNS">
+    <a-select
+      mode="tags"
+      v-model="inbound.settings.dns"
+      :style="{ width: '100%' }"
+      :token-separators="[',']"
+      placeholder="DNS servers"
+    ></a-select>
+  </a-form-item>
   <a-form-item>
     <template slot="label">
       <a-tooltip>
@@ -49,5 +75,20 @@
       placeholder="0"
     ></a-input-number>
   </a-form-item>
+  <a-form-item label="Auto Routing Table">
+    <a-select
+      mode="tags"
+      v-model="inbound.settings.autoSystemRoutingTable"
+      :style="{ width: '100%' }"
+      :token-separators="[',']"
+      placeholder="e.g. vpn, proxy"
+    ></a-select>
+  </a-form-item>
+  <a-form-item label="Auto Outbounds">
+    <a-input
+      v-model.trim="inbound.settings.autoOutboundsInterface"
+      placeholder="auto"
+    ></a-input>
+  </a-form-item>
 </a-form>
 {{end}}