support hosts

core/src/main/java/com/github/shadowsocks/bg/LocalDnsService.kt

@@ -23,10 +23,12 @@ package com.github.shadowsocks.bg
 import com.github.shadowsocks.Core.app
 import com.github.shadowsocks.acl.Acl
 import com.github.shadowsocks.core.R
+import com.github.shadowsocks.net.HostsFile
 import com.github.shadowsocks.net.LocalDnsServer
 import com.github.shadowsocks.net.Socks5Endpoint
 import com.github.shadowsocks.net.Subnet
 import com.github.shadowsocks.preference.DataStore
+import com.github.shadowsocks.utils.Key
 import kotlinx.coroutines.CoroutineScope
 import java.net.InetSocketAddress
 import java.net.URI
@@ -49,7 +51,8 @@ object LocalDnsService {
             val dns = URI("dns://${profile.remoteDns}")
             LocalDnsServer(this::resolver,
                     Socks5Endpoint(dns.host, if (dns.port < 0) 53 else dns.port),
-                    DataStore.proxyAddress).apply {
+                    DataStore.proxyAddress,
+                    HostsFile(DataStore.publicStore.getString(Key.hosts) ?: "")).apply {
                 tcp = !profile.udpdns
                 when (profile.route) {
                     Acl.BYPASS_CHN, Acl.BYPASS_LAN_CHN, Acl.GFWLIST, Acl.CUSTOM_RULES -> {

core/src/main/java/com/github/shadowsocks/net/HostsFile.kt

@@ -0,0 +1,39 @@
+/*******************************************************************************
+ *                                                                             *
+ *  Copyright (C) 2019 by Max Lv <max.c.lv@gmail.com>                          *
+ *  Copyright (C) 2019 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.net
+
+import com.github.shadowsocks.utils.computeIfAbsentCompat
+import com.github.shadowsocks.utils.parseNumericAddress
+import java.net.InetAddress
+
+class HostsFile(input: String = "") {
+    private val map = mutableMapOf<String, MutableSet<InetAddress>>()
+    init {
+        for (line in input.lineSequence()) {
+            val entries = line.substringBefore('#').splitToSequence(' ', '\t').filter { it.isNotEmpty() }
+            val address = entries.firstOrNull()?.parseNumericAddress() ?: continue
+            for (hostname in entries.drop(1)) map.computeIfAbsentCompat(hostname) { LinkedHashSet(1) }.add(address)
+        }
+    }
+
+    val configuredHostnames get() = map.size
+    fun resolve(hostname: String) = map[hostname]?.shuffled() ?: emptyList()
+}

core/src/main/java/com/github/shadowsocks/net/LocalDnsServer.kt

@@ -43,7 +43,9 @@ import java.nio.channels.SocketChannel
  *   https://github.com/shadowsocks/overture/tree/874f22613c334a3b78e40155a55479b7b69fee04
  */
 class LocalDnsServer(private val localResolver: suspend (String) -> Array<InetAddress>,
-                     private val remoteDns: Socks5Endpoint, private val proxy: SocketAddress) : CoroutineScope {
+                     private val remoteDns: Socks5Endpoint,
+                     private val proxy: SocketAddress,
+                     private val hosts: HostsFile) : CoroutineScope {
     /**
      * Forward all requests to remote and ignore localResolver.
      */
@@ -70,7 +72,18 @@ class LocalDnsServer(private val localResolver: suspend (String) -> Array<InetAd
             if (request.header.getFlag(Flags.RD.toInt())) header.setFlag(Flags.RD.toInt())
             request.question?.also { addRecord(it, Section.QUESTION) }
         }
+
+        private fun cookDnsResponse(request: Message, results: Iterable<InetAddress>) =
+                ByteBuffer.wrap(prepareDnsResponse(request).apply {
+                    header.setFlag(Flags.RA.toInt())   // recursion available
+                    for (address in results) addRecord(when (address) {
+                        is Inet4Address -> ARecord(question.name, DClass.IN, TTL, address)
+                        is Inet6Address -> AAAARecord(question.name, DClass.IN, TTL, address)
+                        else -> throw IllegalStateException("Unsupported address $address")
+                    }, Section.ANSWER)
+                }.toWire())
     }
+
     private val monitor = ChannelMonitor()
 
     private val job = SupervisorJob()
@@ -102,10 +115,16 @@ class LocalDnsServer(private val localResolver: suspend (String) -> Array<InetAd
         return supervisorScope {
             val remote = async { withTimeout(TIMEOUT) { forward(packet) } }
             try {
-                if (forwardOnly || request.header.opcode != Opcode.QUERY) return@supervisorScope remote.await()
+                if (request.header.opcode != Opcode.QUERY) return@supervisorScope remote.await()
                 val question = request.question
                 if (question?.type != Type.A) return@supervisorScope remote.await()
                 val host = question.name.toString(true)
+                val hostsResults = hosts.resolve(host)
+                if (hostsResults.isNotEmpty()) {
+                    remote.cancel()
+                    return@supervisorScope cookDnsResponse(request, hostsResults)
+                }
+                if (forwardOnly) return@supervisorScope remote.await()
                 if (remoteDomainMatcher?.containsMatchIn(host) == true) return@supervisorScope remote.await()
                 val localResults = try {
                     withTimeout(TIMEOUT) { GlobalScope.async(Dispatchers.IO) { localResolver(host) }.await() }
@@ -118,14 +137,7 @@ class LocalDnsServer(private val localResolver: suspend (String) -> Array<InetAd
                 if (localResults.isEmpty()) return@supervisorScope remote.await()
                 if (localIpMatcher.isEmpty() || localIpMatcher.any { subnet -> localResults.any(subnet::matches) }) {
                     remote.cancel()
-                    ByteBuffer.wrap(prepareDnsResponse(request).apply {
-                        header.setFlag(Flags.RA.toInt())   // recursion available
-                        for (address in localResults) addRecord(when (address) {
-                            is Inet4Address -> ARecord(question.name, DClass.IN, TTL, address)
-                            is Inet6Address -> AAAARecord(question.name, DClass.IN, TTL, address)
-                            else -> throw IllegalStateException("Unsupported address $address")
-                        }, Section.ANSWER)
-                    }.toWire())
+                    cookDnsResponse(request, localResults.asIterable())
                 } else remote.await()
             } catch (e: Exception) {
                 remote.cancel()

core/src/main/java/com/github/shadowsocks/preference/EditTextPreferenceModifiers.kt

@@ -0,0 +1,45 @@
+/*******************************************************************************
+ *                                                                             *
+ *  Copyright (C) 2019 by Max Lv <max.c.lv@gmail.com>                          *
+ *  Copyright (C) 2019 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.preference
+
+import android.graphics.Typeface
+import android.text.InputFilter
+import android.view.inputmethod.EditorInfo
+import android.widget.EditText
+import androidx.preference.EditTextPreference
+
+object EditTextPreferenceModifiers {
+    object Monospace : EditTextPreference.OnBindEditTextListener {
+        override fun onBindEditText(editText: EditText) {
+            editText.typeface = Typeface.MONOSPACE
+        }
+    }
+
+    object Port : EditTextPreference.OnBindEditTextListener {
+        private val portLengthFilter = arrayOf(InputFilter.LengthFilter(5))
+
+        override fun onBindEditText(editText: EditText) {
+            editText.inputType = EditorInfo.TYPE_CLASS_NUMBER
+            editText.filters = portLengthFilter
+            editText.setSingleLine()
+        }
+    }
+}

core/src/main/java/com/github/shadowsocks/preference/PortPreferenceListener.kt → core/src/main/java/com/github/shadowsocks/preference/HostsSummaryProvider.kt

@@ -20,17 +20,14 @@
 
 package com.github.shadowsocks.preference
 
-import android.text.InputFilter
-import android.view.inputmethod.EditorInfo
-import android.widget.EditText
 import androidx.preference.EditTextPreference
+import androidx.preference.Preference
+import com.github.shadowsocks.core.R
+import com.github.shadowsocks.net.HostsFile
 
-object PortPreferenceListener : EditTextPreference.OnBindEditTextListener {
-    private val portLengthFilter = arrayOf(InputFilter.LengthFilter(5))
-
-    override fun onBindEditText(editText: EditText) {
-        editText.inputType = EditorInfo.TYPE_CLASS_NUMBER
-        editText.filters = portLengthFilter
-        editText.setSingleLine()
+object HostsSummaryProvider : Preference.SummaryProvider<EditTextPreference> {
+    override fun provideSummary(preference: EditTextPreference?): CharSequence {
+        val count = HostsFile(preference!!.text ?: "").configuredHostnames
+        return preference.context.resources.getQuantityString(R.plurals.hosts_summary, count, count)
     }
 }

core/src/main/java/com/github/shadowsocks/utils/Constants.kt

@@ -65,6 +65,7 @@ object Key {
     const val dirty = "profileDirty"
 
     const val tfo = "tcp_fastopen"
+    const val hosts = "hosts"
     const val assetUpdateTime = "assetUpdateTime"
 
     // TV specific values

core/src/main/java/com/github/shadowsocks/utils/Utils.kt

@@ -54,9 +54,12 @@ private val parseNumericAddress by lazy {
  *
  * Bug: https://issuetracker.google.com/issues/123456213
  */
-fun String?.parseNumericAddress(): InetAddress? = Os.inet_pton(OsConstants.AF_INET, this)
+fun String.parseNumericAddress(): InetAddress? = Os.inet_pton(OsConstants.AF_INET, this)
         ?: Os.inet_pton(OsConstants.AF_INET6, this)?.let { parseNumericAddress.invoke(null, this) as InetAddress }
 
+fun <K, V> MutableMap<K, V>.computeIfAbsentCompat(key: K, value: () -> V) = if (Build.VERSION.SDK_INT >= 24)
+    computeIfAbsent(key) { value() } else this[key] ?: value().also { put(key, it) }
+
 fun HttpURLConnection.disconnectFromMain() {
     if (Build.VERSION.SDK_INT >= 26) disconnect() else GlobalScope.launch(Dispatchers.IO) { disconnect() }
 }

core/src/main/res/values/strings.xml

@@ -61,6 +61,10 @@
   <string name="tcp_fastopen_summary">Toggling might require ROOT permission</string>
   <string name="tcp_fastopen_summary_unsupported">Unsupported kernel version: %s &lt; 3.7.1</string>
   <string name="tcp_fastopen_failure">Toggle failed</string>
+  <plurals name="hosts_summary">
+    <item quantity="one">1 hostname configured</item>
+    <item quantity="other">%d hostnames configured</item>
+  </plurals>
   <string name="udp_dns">Send DNS over UDP</string>
   <string name="udp_dns_summary">Requires UDP forwarding on server side</string>
   <string name="udp_fallback">UDP Fallback</string>
@@ -82,7 +86,6 @@
   <!-- alert category -->
   <string name="profile_empty">Please select a profile</string>
   <string name="proxy_empty">Proxy/Password should not be empty</string>
-  <string name="file_manager_missing">Please install a file manager like MiXplorer</string>
   <string name="connect">Connect</string>
 
   <!-- menu category -->

mobile/src/main/java/com/github/shadowsocks/GlobalSettingsPreferenceFragment.kt

@@ -20,6 +20,8 @@
 
 package com.github.shadowsocks
 
+import android.app.Activity
+import android.content.Intent
 import android.os.Build
 import android.os.Bundle
 import androidx.preference.EditTextPreference
@@ -31,10 +33,19 @@ import com.github.shadowsocks.preference.DataStore
 import com.github.shadowsocks.utils.DirectBoot
 import com.github.shadowsocks.utils.Key
 import com.github.shadowsocks.net.TcpFastOpen
-import com.github.shadowsocks.preference.PortPreferenceListener
+import com.github.shadowsocks.preference.BrowsableEditTextPreferenceDialogFragment
+import com.github.shadowsocks.preference.EditTextPreferenceModifiers
+import com.github.shadowsocks.preference.HostsSummaryProvider
+import com.github.shadowsocks.utils.readableMessage
 import com.github.shadowsocks.utils.remove
 
 class GlobalSettingsPreferenceFragment : PreferenceFragmentCompat() {
+    companion object {
+        private const val REQUEST_BROWSE = 1
+    }
+
+    private val hosts by lazy { findPreference<EditTextPreference>(Key.hosts)!! }
+
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
         preferenceManager.preferenceDataStore = DataStore.publicStore
         DataStore.initGlobal()
@@ -70,34 +81,34 @@ class GlobalSettingsPreferenceFragment : PreferenceFragmentCompat() {
             tfo.summary = getString(R.string.tcp_fastopen_summary_unsupported, System.getProperty("os.version"))
         }
 
+        hosts.onBindEditTextListener = EditTextPreferenceModifiers.Monospace
+        hosts.summaryProvider = HostsSummaryProvider
         val serviceMode = findPreference<Preference>(Key.serviceMode)!!
         val portProxy = findPreference<EditTextPreference>(Key.portProxy)!!
-        portProxy.onBindEditTextListener = PortPreferenceListener
+        portProxy.onBindEditTextListener = EditTextPreferenceModifiers.Port
         val portLocalDns = findPreference<EditTextPreference>(Key.portLocalDns)!!
-        portLocalDns.onBindEditTextListener = PortPreferenceListener
+        portLocalDns.onBindEditTextListener = EditTextPreferenceModifiers.Port
         val portTransproxy = findPreference<EditTextPreference>(Key.portTransproxy)!!
-        portTransproxy.onBindEditTextListener = PortPreferenceListener
+        portTransproxy.onBindEditTextListener = EditTextPreferenceModifiers.Port
         val onServiceModeChange = Preference.OnPreferenceChangeListener { _, newValue ->
             val (enabledLocalDns, enabledTransproxy) = when (newValue as String?) {
                 Key.modeProxy -> Pair(false, false)
                 Key.modeVpn -> Pair(true, false)
                 Key.modeTransproxy -> Pair(true, true)
                 else -> throw IllegalArgumentException("newValue: $newValue")
             }
+            hosts.isEnabled = enabledLocalDns
             portLocalDns.isEnabled = enabledLocalDns
             portTransproxy.isEnabled = enabledTransproxy
             true
         }
         val listener: (BaseService.State) -> Unit = {
-            if (it == BaseService.State.Stopped) {
-                tfo.isEnabled = true
-                serviceMode.isEnabled = true
-                portProxy.isEnabled = true
-                onServiceModeChange.onPreferenceChange(null, DataStore.serviceMode)
-            } else {
-                tfo.isEnabled = false
-                serviceMode.isEnabled = false
-                portProxy.isEnabled = false
+            val stopped = it == BaseService.State.Stopped
+            tfo.isEnabled = stopped
+            serviceMode.isEnabled = stopped
+            portProxy.isEnabled = stopped
+            if (stopped) onServiceModeChange.onPreferenceChange(null, DataStore.serviceMode) else {
+                hosts.isEnabled = false
                 portLocalDns.isEnabled = false
                 portTransproxy.isEnabled = false
             }
@@ -107,6 +118,29 @@ class GlobalSettingsPreferenceFragment : PreferenceFragmentCompat() {
         serviceMode.onPreferenceChangeListener = onServiceModeChange
     }
 
+    override fun onDisplayPreferenceDialog(preference: Preference?) {
+        if (preference == hosts) BrowsableEditTextPreferenceDialogFragment().apply {
+            setKey(hosts.key)
+            setTargetFragment(this@GlobalSettingsPreferenceFragment, REQUEST_BROWSE)
+        }.show(fragmentManager ?: return, hosts.key) else super.onDisplayPreferenceDialog(preference)
+    }
+
+    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+        when (requestCode) {
+            REQUEST_BROWSE -> {
+                if (resultCode != Activity.RESULT_OK) return
+                val activity = activity as MainActivity
+                try {
+                    // we read and persist all its content here to avoid content URL permission issues
+                    hosts.text = activity.contentResolver.openInputStream(data!!.data!!)!!.bufferedReader().readText()
+                } catch (e: RuntimeException) {
+                    activity.snackbar(e.readableMessage).show()
+                }
+            }
+            else -> super.onActivityResult(requestCode, resultCode, data)
+        }
+    }
+
     override fun onDestroy() {
         MainActivity.stateListener = null
         super.onDestroy()

mobile/src/main/java/com/github/shadowsocks/ProfileConfigFragment.kt

@@ -74,7 +74,7 @@ class ProfileConfigFragment : PreferenceFragmentCompat(),
         val activity = requireActivity()
         profileId = activity.intent.getLongExtra(Action.EXTRA_PROFILE_ID, -1L)
         addPreferencesFromResource(R.xml.pref_profile)
-        findPreference<EditTextPreference>(Key.remotePort)!!.onBindEditTextListener = PortPreferenceListener
+        findPreference<EditTextPreference>(Key.remotePort)!!.onBindEditTextListener = EditTextPreferenceModifiers.Port
         findPreference<EditTextPreference>(Key.password)!!.summaryProvider = PasswordSummaryProvider
         val serviceMode = DataStore.serviceMode
         findPreference<Preference>(Key.remoteDns)!!.isEnabled = serviceMode != Key.modeProxy
@@ -104,6 +104,7 @@ class ProfileConfigFragment : PreferenceFragmentCompat(),
             }
             true
         }
+        pluginConfigure.onBindEditTextListener = EditTextPreferenceModifiers.Monospace
         pluginConfigure.onPreferenceChangeListener = this
         initPlugins()
         receiver = Core.listenForPackageChanges(false) { initPlugins() }