Added MTU In Settings (#4828)

Added MTU In Settings.
Closes  #4824

V2rayNG/app/src/main/java/com/v2ray/ang/AppConfig.kt

@@ -27,6 +27,7 @@ object AppConfig {
     const val PREF_VPN_DNS = "pref_vpn_dns"
     const val PREF_VPN_BYPASS_LAN = "pref_vpn_bypass_lan"
     const val PREF_VPN_INTERFACE_ADDRESS_CONFIG_INDEX = "pref_vpn_interface_address_config_index"
+    const val PREF_VPN_MTU = "pref_vpn_mtu"
     const val PREF_ROUTING_DOMAIN_STRATEGY = "pref_routing_domain_strategy"
     const val PREF_ROUTING_RULESET = "pref_routing_ruleset"
     const val PREF_MUX_ENABLED = "pref_mux_enabled"

V2rayNG/app/src/main/java/com/v2ray/ang/handler/SettingsManager.kt

@@ -370,4 +370,11 @@ object SettingsManager {
         val selectedIndex = MmkvManager.decodeSettingsString(AppConfig.PREF_VPN_INTERFACE_ADDRESS_CONFIG_INDEX, "0")?.toInt()
         return VpnInterfaceAddressConfig.getConfigByIndex(selectedIndex ?: 0)
     }
+
+    /**
+     * Get the VPN MTU from settings, defaulting to AppConfig.VPN_MTU.
+     */
+    fun getVpnMtu(): Int {
+        return Utils.parseInt(MmkvManager.decodeSettingsString(AppConfig.PREF_VPN_MTU), AppConfig.VPN_MTU)
+    }
 }

V2rayNG/app/src/main/java/com/v2ray/ang/service/TProxyService.kt

@@ -4,7 +4,6 @@ import android.content.Context
 import android.os.ParcelFileDescriptor
 import android.util.Log
 import com.v2ray.ang.AppConfig
-import com.v2ray.ang.AppConfig.VPN_MTU
 import com.v2ray.ang.handler.MmkvManager
 import com.v2ray.ang.handler.SettingsManager
 import java.io.File
@@ -60,7 +59,7 @@ class TProxyService(
         val vpnConfig = SettingsManager.getCurrentVpnInterfaceAddressConfig()
         return buildString {
             appendLine("tunnel:")
-            appendLine("  mtu: $VPN_MTU")
+            appendLine("  mtu: ${SettingsManager.getVpnMtu()}")
             appendLine("  ipv4: ${vpnConfig.ipv4Client}")
 
             if (MmkvManager.decodeSettingsBool(AppConfig.PREF_PREFER_IPV6) == true) {

V2rayNG/app/src/main/java/com/v2ray/ang/service/Tun2SocksService.kt

@@ -6,7 +6,6 @@ import android.net.LocalSocketAddress
 import android.os.ParcelFileDescriptor
 import android.util.Log
 import com.v2ray.ang.AppConfig
-import com.v2ray.ang.AppConfig.VPN_MTU
 import com.v2ray.ang.handler.MmkvManager
 import com.v2ray.ang.handler.SettingsManager
 import com.v2ray.ang.util.Utils
@@ -42,7 +41,7 @@ class Tun2SocksService(
             "--netif-ipaddr", vpnConfig.ipv4Router,
             "--netif-netmask", "255.255.255.252",
             "--socks-server-addr", "${AppConfig.LOOPBACK}:${socksPort}",
-            "--tunmtu", VPN_MTU.toString(),
+            "--tunmtu", SettingsManager.getVpnMtu().toString(),
             "--sock-path", "sock_path",
             "--enable-udprelay",
             "--loglevel", "notice"

V2rayNG/app/src/main/java/com/v2ray/ang/service/V2RayVpnService.kt

@@ -17,7 +17,6 @@ import android.util.Log
 import androidx.annotation.RequiresApi
 import com.v2ray.ang.AppConfig
 import com.v2ray.ang.AppConfig.LOOPBACK
-import com.v2ray.ang.AppConfig.VPN_MTU
 import com.v2ray.ang.BuildConfig
 import com.v2ray.ang.handler.MmkvManager
 import com.v2ray.ang.handler.NotificationManager
@@ -185,7 +184,7 @@ class V2RayVpnService : VpnService(), ServiceControl {
         val bypassLan = SettingsManager.routingRulesetsBypassLan()
 
         // Configure IPv4 settings
-        builder.setMtu(VPN_MTU)
+        builder.setMtu(SettingsManager.getVpnMtu())
         builder.addAddress(vpnConfig.ipv4Client, 30)
 
         // Configure routing rules

V2rayNG/app/src/main/java/com/v2ray/ang/ui/SettingsActivity.kt

@@ -45,6 +45,7 @@ class SettingsActivity : BaseActivity() {
         private val vpnDns by lazy { findPreference<EditTextPreference>(AppConfig.PREF_VPN_DNS) }
         private val vpnBypassLan by lazy { findPreference<ListPreference>(AppConfig.PREF_VPN_BYPASS_LAN) }
         private val vpnInterfaceAddress by lazy { findPreference<ListPreference>(AppConfig.PREF_VPN_INTERFACE_ADDRESS_CONFIG_INDEX) }
+        private val vpnMtu by lazy { findPreference<EditTextPreference>(AppConfig.PREF_VPN_MTU) }
 
         private val mux by lazy { findPreference<CheckBoxPreference>(AppConfig.PREF_MUX_ENABLED) }
         private val muxConcurrency by lazy { findPreference<EditTextPreference>(AppConfig.PREF_MUX_CONCURRENCY) }
@@ -93,6 +94,12 @@ class SettingsActivity : BaseActivity() {
                 true
             }
 
+            vpnMtu?.setOnPreferenceChangeListener { _, any ->
+                val nval = any as String
+                vpnMtu?.summary = if (TextUtils.isEmpty(nval)) AppConfig.VPN_MTU.toString() else nval
+                true
+            }
+
             mux?.setOnPreferenceChangeListener { _, newValue ->
                 updateMux(newValue as Boolean)
                 true
@@ -196,6 +203,7 @@ class SettingsActivity : BaseActivity() {
             appendHttpProxy?.isChecked = MmkvManager.decodeSettingsBool(AppConfig.PREF_APPEND_HTTP_PROXY, false)
             localDnsPort?.summary = MmkvManager.decodeSettingsString(AppConfig.PREF_LOCAL_DNS_PORT, AppConfig.PORT_LOCAL_DNS)
             vpnDns?.summary = MmkvManager.decodeSettingsString(AppConfig.PREF_VPN_DNS, AppConfig.DNS_VPN)
+            vpnMtu?.summary = MmkvManager.decodeSettingsString(AppConfig.PREF_VPN_MTU, AppConfig.VPN_MTU.toString())
 
             updateMux(MmkvManager.decodeSettingsBool(AppConfig.PREF_MUX_ENABLED, false))
             mux?.isChecked = MmkvManager.decodeSettingsBool(AppConfig.PREF_MUX_ENABLED, false)
@@ -229,6 +237,7 @@ class SettingsActivity : BaseActivity() {
             listOf(
                 localDnsPort,
                 vpnDns,
+                vpnMtu,
                 muxConcurrency,
                 muxXudpConcurrency,
                 fragmentLength,
@@ -298,6 +307,7 @@ class SettingsActivity : BaseActivity() {
             vpnDns?.isEnabled = vpn
             vpnBypassLan?.isEnabled = vpn
             vpnInterfaceAddress?.isEnabled = vpn
+            vpnMtu?.isEnabled = vpn
             if (vpn) {
                 updateLocalDns(
                     MmkvManager.decodeSettingsBool(

V2rayNG/app/src/main/res/values/strings.xml

@@ -185,6 +185,7 @@
     <string name="title_pref_vpn_bypass_lan">Does VPN bypass LAN</string>
 
     <string name="title_pref_vpn_interface_address">VPN Interface Address</string>
+    <string name="title_pref_vpn_mtu">VPN MTU</string>
 
     <string name="title_pref_domestic_dns">Domestic DNS (Optional)</string>
     <string name="summary_pref_domestic_dns">DNS</string>

V2rayNG/app/src/main/res/xml/pref_settings.xml

@@ -72,6 +72,12 @@
             android:summary="%s"
             android:title="@string/title_pref_vpn_interface_address" />
 
+        <EditTextPreference
+            android:inputType="number"
+            android:key="pref_vpn_mtu"
+            android:summary="1500"
+            android:title="@string/title_pref_vpn_mtu" />
+
         <CheckBoxPreference
             android:key="pref_use_hev_tunnel"
             android:summary="@string/summary_pref_use_hev_tunnel"