Add vpn dns preference setting

Vpn Dns can now be changed separately from remote Dns

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

@@ -19,6 +19,7 @@ object AppConfig {
     const val PREF_PROXY_SHARING = "pref_proxy_sharing_enabled"
     const val PREF_LOCAL_DNS_ENABLED = "pref_local_dns_enabled"
     const val PREF_FAKE_DNS_ENABLED = "pref_fake_dns_enabled"
+    const val PREF_VPN_DNS = "pref_vpn_dns"
     const val PREF_REMOTE_DNS = "pref_remote_dns"
     const val PREF_DOMESTIC_DNS = "pref_domestic_dns"
     const val PREF_FORWARD_IPV6 = "pref_forward_ipv6"

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

@@ -122,10 +122,12 @@ class V2RayVpnService : VpnService(), ServiceControl {
                 }
 
         if(!enableLocalDns) {
-            Utils.getRemoteDnsServers()
-                .forEach {
-                    builder.addDnsServer(it)
-                }
+            Utils.getVpnDnsServers()
+                    .forEach {
+                        if (Utils.isPureIpAddress(it)) {
+                            builder.addDnsServer(it)
+                        }
+                    }
         }
 
         builder.setSession(V2RayServiceManager.currentConfig?.remarks.orEmpty())

V2rayNG/app/src/main/kotlin/com/v2ray/ang/util/Utils.kt

@@ -15,7 +15,6 @@ import android.content.ClipData
 import android.content.Intent
 import android.net.Uri
 import android.os.SystemClock
-import android.text.TextUtils
 import android.util.Log
 import android.util.Patterns
 import android.webkit.URLUtil
@@ -123,41 +122,31 @@ object Utils {
     /**
      * get remote dns servers from preference
      */
-    fun getRemoteDnsServers(): ArrayList<String> {
+    fun getRemoteDnsServers(): List<String> {
         val remoteDns = settingsStorage?.decodeString(AppConfig.PREF_REMOTE_DNS) ?: AppConfig.DNS_AGENT
-        val ret = ArrayList<String>()
-        if (!TextUtils.isEmpty(remoteDns)) {
-            remoteDns
-                    .split(",")
-                    .forEach {
-                        if (Utils.isPureIpAddress(it)) {
-                            ret.add(it)
-                        }
-                    }
-        }
-        if (ret.size == 0) {
-            ret.add(AppConfig.DNS_AGENT)
+        val ret = remoteDns.split(",").filter { isPureIpAddress(it) || it.startsWith("https") }
+        if (ret.isEmpty()) {
+            return listOf(AppConfig.DNS_AGENT)
         }
         return ret
     }
 
+    fun getVpnDnsServers(): List<String> {
+        val vpnDns = settingsStorage?.decodeString(AppConfig.PREF_VPN_DNS)
+                ?: settingsStorage?.decodeString(AppConfig.PREF_REMOTE_DNS)
+                ?: AppConfig.DNS_AGENT
+        return vpnDns.split(",").filter { isPureIpAddress(it) }
+        // allow empty, in that case dns will use system default
+    }
+
     /**
      * get remote dns servers from preference
      */
-    fun getDomesticDnsServers(): ArrayList<String> {
+    fun getDomesticDnsServers(): List<String> {
         val domesticDns = settingsStorage?.decodeString(AppConfig.PREF_DOMESTIC_DNS) ?: AppConfig.DNS_DIRECT
-        val ret = ArrayList<String>()
-        if (!TextUtils.isEmpty(domesticDns)) {
-            domesticDns
-                    .split(",")
-                    .forEach {
-                        if (Utils.isPureIpAddress(it)) {
-                            ret.add(it)
-                        }
-                    }
-        }
-        if (ret.size == 0) {
-            ret.add(AppConfig.DNS_DIRECT)
+        val ret = domesticDns.split(",").filter { isPureIpAddress(it) || it.startsWith("https") }
+        if (ret.isEmpty()) {
+            return listOf(AppConfig.DNS_DIRECT)
         }
         return ret
     }
@@ -391,7 +380,7 @@ object Utils {
             val command = "/system/bin/ping -c 3 $url"
             val process = Runtime.getRuntime().exec(command)
             val allText = process.inputStream.bufferedReader().use { it.readText() }
-            if (!TextUtils.isEmpty(allText)) {
+            if (allText.isNotBlank()) {
                 val tempInfo = allText.substring(allText.indexOf("min/avg/max/mdev") + 19)
                 val temps = tempInfo.split("/".toRegex()).dropLastWhile({ it.isEmpty() }).toTypedArray()
                 if (temps.count() > 0 && temps[0].length < 10) {

V2rayNG/app/src/main/kotlin/com/v2ray/ang/viewmodel/SettingsViewModel.kt

@@ -27,6 +27,7 @@ class SettingsViewModel(application: Application) : AndroidViewModel(application
         Log.d(AppConfig.ANG_PACKAGE, "Observe settings changed: $key")
         when(key) {
             AppConfig.PREF_MODE,
+            AppConfig.PREF_VPN_DNS,
             AppConfig.PREF_REMOTE_DNS,
             AppConfig.PREF_DOMESTIC_DNS,
             AppConfig.PREF_ROUTING_DOMAIN_STRATEGY,