Remove TCP resolving of hostnames

mobile/build.gradle

@@ -74,7 +74,6 @@ dependencies {
     implementation 'com.squareup.okhttp3:okhttp:3.10.0'
     implementation "com.takisoft.fix:preference-v7-simplemenu:$takisoftFixVersion"
     implementation 'com.twofortyfouram:android-plugin-api-for-locale:1.0.2'
-    implementation 'dnsjava:dnsjava:2.1.8'
     implementation 'eu.chainfire:libsuperuser:1.0.0.201704021214'
     implementation 'net.glxn.qrgen:android:2.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"

mobile/src/main/java/com/github/shadowsocks/bg/BaseService.kt

@@ -50,7 +50,7 @@ import okhttp3.Request
 import org.json.JSONObject
 import java.io.File
 import java.io.IOException
-import java.net.UnknownHostException
+import java.net.*
 import java.security.MessageDigest
 import java.util.*
 import java.util.concurrent.TimeUnit
@@ -364,10 +364,6 @@ object BaseService {
                 try {
                     if (profile.host == "198.199.101.152") {
                         val client = OkHttpClient.Builder()
-                                .dns {
-                                    listOf((Dns.resolve(it, false) ?: throw UnknownHostException())
-                                            .parseNumericAddress())
-                                }
                                 .connectTimeout(10, TimeUnit.SECONDS)
                                 .writeTimeout(10, TimeUnit.SECONDS)
                                 .readTimeout(30, TimeUnit.SECONDS)
@@ -402,7 +398,7 @@ object BaseService {
                     killProcesses()
 
                     if (!profile.host.isNumericAddress())
-                        profile.host = Dns.resolve(profile.host, true) ?: throw UnknownHostException()
+                        profile.host = InetAddress.getByName(profile.host).hostAddress ?: throw UnknownHostException()
 
                     startNativeProcesses()
 

mobile/src/main/java/com/github/shadowsocks/bg/Dns.kt

@@ -1,72 +0,0 @@
-/*******************************************************************************
- *                                                                             *
- *  Copyright (C) 2017 by Max Lv <max.c.lv@gmail.com>                          *
- *  Copyright (C) 2017 by Mygod Studio <contact-shadowsocks-android@mygod.be>  *
- *                                                                             *
- *  This program is free software: you can redistribute it and/or modify       *
- *  it under the terms of the GNU General Public License as published by       *
- *  the Free Software Foundation, either version 3 of the License, or          *
- *  (at your option) any later version.                                        *
- *                                                                             *
- *  This program is distributed in the hope that it will be useful,            *
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of             *
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
- *  GNU General Public License for more details.                               *
- *                                                                             *
- *  You should have received a copy of the GNU General Public License          *
- *  along with this program. If not, see <http://www.gnu.org/licenses/>.       *
- *                                                                             *
- *******************************************************************************/
-
-package com.github.shadowsocks.bg
-
-import android.util.Log
-import com.github.shadowsocks.App.Companion.app
-import com.github.shadowsocks.BuildConfig
-import org.xbill.DNS.*
-import java.io.IOException
-import java.net.*
-
-object Dns {
-    private const val TAG = "Dns"
-
-    private val hasIPv6Support get() = try {
-        val result = NetworkInterface.getNetworkInterfaces().asSequence().flatMap { it.inetAddresses.asSequence() }
-                .any { it is Inet6Address && !it.isLoopbackAddress && !it.isLinkLocalAddress }
-        if (result && BuildConfig.DEBUG) Log.d(TAG, "IPv6 address detected")
-        result
-    } catch (ex: SocketException) {
-        Log.e(TAG, "Failed to get interfaces' addresses.", ex)
-        app.track(ex)
-        false
-    }
-
-    private fun resolve(host: String, addrType: Int): String? {
-        try {
-            val lookup = Lookup(host, addrType)
-            val resolver = SimpleResolver("208.67.220.220")
-            resolver.setTCP(true)
-            resolver.setPort(443)
-            resolver.setTimeout(5)
-            lookup.setResolver(resolver)
-            val records = (lookup.run() ?: return null).toMutableList()
-            records.shuffle()
-            for (r in records) {
-                when (addrType) {
-                    Type.A -> return (r as ARecord).address.hostAddress
-                    Type.AAAA -> return (r as AAAARecord).address.hostAddress
-                }
-            }
-        } catch (_: IOException) { }
-        return null
-    }
-    private fun resolve(host: String): String? = try {
-        InetAddress.getByName(host).hostAddress
-    } catch (_: UnknownHostException) {
-        null
-    }
-    fun resolve(host: String, enableIPv6: Boolean): String? =
-            (if (enableIPv6 && hasIPv6Support) resolve(host, Type.AAAA) else null)
-                    ?: resolve(host, Type.A)
-                    ?: resolve(host)
-}