Revert "Replace NAT mode with local SOCKS5 mode. shadowsocks#1441"

This reverts commit 7fb19c4.

.gitmodules

@@ -9,6 +9,14 @@
 	path = mobile/src/main/jni/libancillary
 	url = https://github.com/shadowsocks/libancillary.git
 	branch = shadowsocks-android
+[submodule "mobile/src/main/jni/libevent"]
+	path = mobile/src/main/jni/libevent
+	url = https://github.com/shadowsocks/libevent.git
+	branch = shadowsocks-android
+[submodule "mobile/src/main/jni/redsocks"]
+	path = mobile/src/main/jni/redsocks
+	url = https://github.com/shadowsocks/redsocks.git
+	branch = shadowsocks-android
 [submodule "mobile/src/main/jni/mbedtls"]
 	path = mobile/src/main/jni/mbedtls
 	url = https://github.com/ARMmbed/mbedtls

mobile/src/main/AndroidManifest.xml

@@ -12,7 +12,7 @@
                   android:required="false"/>
     <uses-feature android:name="android.software.leanback"
                   android:required="false"/>
-    <uses-feature android:name="android.hardware.camera"
+    <uses-feature android:name="android.hardware.camera"        
                   android:required="false"/>
 
     <uses-sdk
@@ -109,7 +109,7 @@
         </activity>
 
         <service
-                android:name=".ShadowsocksLocalService"
+                android:name=".ShadowsocksNatService"
                 android:process=":bg"
                 android:exported="false">
         </service>

mobile/src/main/jni/Android.mk

@@ -78,6 +78,32 @@ LOCAL_SRC_FILES := $(addprefix libsodium/src/libsodium/,$(SODIUM_SOURCE))
 
 include $(BUILD_STATIC_LIBRARY)
 
+########################################################
+## libevent
+########################################################
+
+include $(CLEAR_VARS)
+
+LIBEVENT_SOURCES := \
+	buffer.c \
+	bufferevent.c bufferevent_filter.c \
+	bufferevent_pair.c bufferevent_ratelim.c \
+	bufferevent_sock.c epoll.c \
+	epoll_sub.c evdns.c event.c \
+    event_tagging.c evmap.c \
+	evrpc.c evthread.c \
+	evthread_pthread.c evutil.c \
+	evutil_rand.c http.c \
+	listener.c log.c poll.c \
+	select.c signal.c strlcpy.c
+
+LOCAL_MODULE := event
+LOCAL_SRC_FILES := $(addprefix libevent/, $(LIBEVENT_SOURCES))
+LOCAL_CFLAGS := -O2 -D_EVENT_HAVE_ARC4RANDOM -I$(LOCAL_PATH)/libevent \
+	-I$(LOCAL_PATH)/libevent/include \
+
+include $(BUILD_STATIC_LIBRARY)
+
 ########################################################
 ## libancillary
 ########################################################
@@ -174,6 +200,28 @@ LOCAL_SRC_FILES := \
 
 include $(BUILD_STATIC_LIBRARY)
 
+########################################################
+## redsocks
+########################################################
+
+include $(CLEAR_VARS)
+
+REDSOCKS_SOURCES := base.c http-connect.c \
+	log.c md5.c socks5.c \
+	base64.c http-auth.c http-relay.c main.c \
+	parser.c redsocks.c socks4.c utils.c
+
+LOCAL_STATIC_LIBRARIES := libevent
+
+LOCAL_MODULE := redsocks
+LOCAL_SRC_FILES := $(addprefix redsocks/, $(REDSOCKS_SOURCES)) 
+LOCAL_CFLAGS := -O2 -std=gnu99 -DUSE_IPTABLES \
+	-I$(LOCAL_PATH)/redsocks \
+	-I$(LOCAL_PATH)/libevent/include \
+	-I$(LOCAL_PATH)/libevent
+
+include $(BUILD_SHARED_EXECUTABLE)
+
 ########################################################
 ## shadowsocks-libev local
 ########################################################

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

@@ -7,8 +7,8 @@
   <!-- misc -->
   <string name="profile">Profile</string>
   <string name="profile_summary">Switch to another profile or add new profiles</string>
-  <string name="local">SOCKS5 mode</string>
-  <string name="local_summary">Enable SOCKS5 proxy mode instead of VPN mode to work with AFWall+ or Orbot</string>
+  <string name="nat">NAT mode (deprecated)</string>
+  <string name="nat_summary">Use NAT mode instead of VPN mode. Requires ROOT permission.</string>
   <string name="remote_dns">Remote DNS</string>
   <string name="stat_summary">Sent: \t\t\t\t\t%3$s\t↑\t%1$s/s\nReceived: \t%4$s\t↓\t%2$s/s</string>
   <string name="stat_profiles">%1$s↑\t%2$s↓</string>
@@ -43,7 +43,7 @@
   <string name="route_entry_gfwlist">GFW List</string>
   <string name="route_entry_chinalist">China List</string>
   <string name="proxied_apps">Per-App Proxy</string>
-  <string name="proxied_apps_summary">Set proxy for selected apps</string>
+  <string name="proxied_apps_summary">Set proxy for selected apps, requires NAT mode under Android 4.x</string>
   <string name="proxied_apps_summary_v21">Set proxy for selected apps</string>
   <string name="on">On</string>
   <string name="bypass_apps">Bypass Mode</string>
@@ -57,10 +57,12 @@
 
   <!-- notification category -->
   <string name="service_vpn">VPN Service</string>
-  <string name="service_local">SOCKS5 Service</string>
+  <string name="service_nat">NAT Service</string>
   <string name="forward_success">Shadowsocks started.</string>
   <string name="invalid_server">Invalid server name</string>
   <string name="service_failed">Failed to connect the remote server</string>
+  <string name="nat_deprecated">WARNING: NAT mode has been deprecated since Android 5.0</string>
+  <string name="nat_no_root">NAT mode requires ROOT permission</string>
   <string name="switch_to_vpn">Switch to VPN mode</string>
   <string name="stop">Stop</string>
   <string name="stopping">Shutting down…</string>
@@ -122,7 +124,7 @@
   <string name="received">Received:</string>
   <string name="connecting">Connecting…</string>
   <string name="vpn_connected">Connected, tap to check connection</string>
-  <string name="local_connected">Connected</string>
+  <string name="nat_connected">Connected</string>
   <string name="not_connected">Not connected</string>
 
   <!-- acl -->

mobile/src/main/res/xml/pref_global.xml

@@ -8,6 +8,6 @@
                       android:summary="@string/tcp_fastopen_summary"
                       android:title="TCP Fast Open"/>
     <SwitchPreference android:key="isNAT"
-                      android:title="@string/local"
-                      android:summary="@string/local_summary"/>
+                      android:title="@string/nat"
+                      android:summary="@string/nat_summary"/>
 </PreferenceScreen>

mobile/src/main/scala/com/github/shadowsocks/MainActivity.scala

@@ -117,7 +117,7 @@ class MainActivity extends Activity with ServiceBoundContext with Drawer.OnDrawe
         if (state == State.CONNECTING) fabProgressCircle.beginFinalAnimation()
         else fabProgressCircle.postDelayed(hideCircle, 1000)
         fab.setImageResource(R.drawable.ic_start_connected)
-        statusText.setText(if (app.isLocalEnabled) R.string.local_connected else R.string.vpn_connected)
+        statusText.setText(if (app.isNatEnabled) R.string.nat_connected else R.string.vpn_connected)
       case State.STOPPING =>
         fab.setImageResource(R.drawable.ic_start_busy)
         if (state == State.CONNECTED) fabProgressCircle.show()  // ignore for stopped
@@ -128,6 +128,7 @@ class MainActivity extends Activity with ServiceBoundContext with Drawer.OnDrawe
         if (m != null) {
           val snackbar = Snackbar.make(findViewById(R.id.snackbar),
             getString(R.string.vpn_error).formatLocal(Locale.ENGLISH, m), Snackbar.LENGTH_LONG)
+          if (m == getString(R.string.nat_no_root)) addDisableNatToSnackbar(snackbar)
           snackbar.show()
           Log.e(TAG, "Error to start VPN service: " + m)
         }
@@ -156,9 +157,16 @@ class MainActivity extends Activity with ServiceBoundContext with Drawer.OnDrawe
 
   override def onServiceConnected() {
     changeState(bgService.getState)
+    if (Build.VERSION.SDK_INT >= 21 && app.isNatEnabled) {
+      val snackbar = Snackbar.make(findViewById(R.id.snackbar), R.string.nat_deprecated, Snackbar.LENGTH_LONG)
+      addDisableNatToSnackbar(snackbar)
+      snackbar.show()
+    }
   }
   override def onServiceDisconnected(): Unit = changeState(State.IDLE)
 
+  private def addDisableNatToSnackbar(snackbar: Snackbar) = snackbar.setAction(R.string.switch_to_vpn, (_ =>
+    if (state == State.STOPPED) app.dataStore.isNAT = false): View.OnClickListener)
 
   override def binderDied(): Unit = handler.post(() => {
     detachService()
@@ -292,7 +300,7 @@ class MainActivity extends Activity with ServiceBoundContext with Drawer.OnDrawe
     fab = findViewById(R.id.fab).asInstanceOf[FloatingActionButton]
     fabProgressCircle = findViewById(R.id.fabProgressCircle).asInstanceOf[FABProgressCircle]
     fab.setOnClickListener(_ => if (state == State.CONNECTED) Utils.stopSsService(this) else Utils.ThrowableFuture {
-      if (app.isLocalEnabled) Utils.startSsService(this) else {
+      if (app.isNatEnabled) Utils.startSsService(this) else {
         val intent = VpnService.prepare(this)
         if (intent != null) startActivityForResult(intent, REQUEST_CONNECT)
         else handler.post(() => onActivityResult(REQUEST_CONNECT, Activity.RESULT_OK, null))

mobile/src/main/scala/com/github/shadowsocks/ProfileConfigFragment.scala

@@ -66,7 +66,7 @@ class ProfileConfigFragment extends PreferenceFragment with OnMenuItemClickListe
       findPreference(Key.password).setSummary("\u2022" * 32)
     }
     isProxyApps = findPreference(Key.proxyApps).asInstanceOf[SwitchPreference]
-    isProxyApps.setEnabled(Utils.isLollipopOrAbove || app.isLocalEnabled)
+    isProxyApps.setEnabled(Utils.isLollipopOrAbove || app.isNatEnabled)
     isProxyApps.setOnPreferenceClickListener(_ => {
       startActivity(new Intent(getActivity, classOf[AppManager]))
       isProxyApps.setChecked(true)

mobile/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala

@@ -85,7 +85,7 @@ trait ServiceBoundContext extends Context with IBinder.DeathRecipient {
   protected def attachService(callback: IShadowsocksServiceCallback.Stub = null) {
     this.callback = callback
     if (bgService == null) {
-      val s = if (app.isLocalEnabled) classOf[ShadowsocksLocalService] else classOf[ShadowsocksVpnService]
+      val s = if (app.isNatEnabled) classOf[ShadowsocksNatService] else classOf[ShadowsocksVpnService]
 
       val intent = new Intent(this, s)
       intent.setAction(Action.SERVICE)

mobile/src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala

@@ -66,8 +66,8 @@ class ShadowsocksApplication extends Application {
   lazy val profileManager = new ProfileManager(dbHelper)
   lazy val dataStore = new OrmLitePreferenceDataStore(dbHelper)
 
-  def isLocalEnabled: Boolean = dataStore.isNAT
-  def isVpnEnabled: Boolean = !isLocalEnabled
+  def isNatEnabled: Boolean = dataStore.isNAT
+  def isVpnEnabled: Boolean = !isNatEnabled
 
   // send event
   def track(category: String, action: String): Unit = tracker.send(new HitBuilders.EventBuilder()
@@ -156,7 +156,7 @@ class ShadowsocksApplication extends Application {
 
     if (Build.VERSION.SDK_INT >= 26) getSystemService(classOf[NotificationManager]).createNotificationChannels(List(
       new NotificationChannel("service-vpn", getText(R.string.service_vpn), NotificationManager.IMPORTANCE_MIN),
-      new NotificationChannel("service-local", getText(R.string.service_local), NotificationManager.IMPORTANCE_LOW)
+      new NotificationChannel("service-nat", getText(R.string.service_nat), NotificationManager.IMPORTANCE_LOW)
     ))
   }
 
@@ -165,9 +165,15 @@ class ShadowsocksApplication extends Application {
 
     for (task <- Executable.EXECUTABLES) {
       cmd.append("killall lib%s.so".formatLocal(Locale.ENGLISH, task))
-      cmd.append("rm -f %1$s/%2$s-local.conf %1$s/%2$s-vpn.conf"
+      cmd.append("rm -f %1$s/%2$s-nat.conf %1$s/%2$s-vpn.conf"
         .formatLocal(Locale.ENGLISH, getFilesDir.getAbsolutePath, task))
     }
+    if (app.isNatEnabled) {
+      cmd.append("iptables -t nat -F OUTPUT")
+      cmd.append("echo done")
+      val result = Shell.SU.run(cmd.toArray)
+      if (result != null && !result.isEmpty) return // fallback to SH
+    }
     Shell.SH.run(cmd.toArray)
   }