Revert "Revert "Fix #839 #838""

This reverts commit 264b177b38.

src/main/res/xml/pref_all.xml

@@ -112,7 +112,6 @@
 
         <SwitchPreference
                 android:key="tcp_fastopen"
-                android:persistent="false"
                 android:summary="@string/tcp_fastopen_summary"
                 android:title="TCP Fast Open"/>
 

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

@@ -46,7 +46,7 @@ import android.app.Application
 import android.preference.PreferenceManager
 import android.support.v7.app.AppCompatDelegate
 import com.github.shadowsocks.database.{DBHelper, ProfileManager}
-import com.github.shadowsocks.utils.{Key, Utils}
+import com.github.shadowsocks.utils.{Key, Utils, TcpFastOpen}
 import com.google.android.gms.analytics.{GoogleAnalytics, HitBuilders, StandardExceptionParser}
 import com.google.android.gms.common.api.ResultCallback
 import com.google.android.gms.tagmanager.{ContainerHolder, TagManager}
@@ -111,6 +111,13 @@ class ShadowsocksApplication extends Application {
       }
     }
     pending.setResultCallback(callback, 2, TimeUnit.SECONDS)
+
+    // TFO
+    val tfo = settings.getBoolean(Key.tfo, false)
+    if (tfo && !TcpFastOpen.isEnabled)
+    {
+      TcpFastOpen.enabled(true)
+    }
   }
 
   def refreshContainerHolder {

src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala

@@ -105,7 +105,7 @@ class ShadowsocksNatService extends BaseService {
 
     if (profile.auth) cmd += "-A"
 
-    if (TcpFastOpen.sendEnabled) cmd += "--fast-open"
+    if (TcpFastOpen.isEnabled) cmd += "--fast-open"
 
     if (profile.route != Route.ALL) {
       cmd += "--acl"

src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala

@@ -155,14 +155,17 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
     }
     switch.setChecked(BootReceiver.getEnabled(activity))
 
-    val tfo = findPreference("tcp_fastopen").asInstanceOf[SwitchPreference]
-    tfo.setChecked(TcpFastOpen.sendEnabled)
+    if (getPreferenceManager.getSharedPreferences.getBoolean(Key.tfo, false) && !TcpFastOpen.isEnabled) {
+      TcpFastOpen.enabled(true)
+    }
+    val tfo = findPreference(Key.tfo).asInstanceOf[SwitchPreference]
+    tfo.setChecked(TcpFastOpen.isEnabled)
     tfo.setOnPreferenceChangeListener((_, v) => {
       val value = v.asInstanceOf[Boolean]
       val result = TcpFastOpen.enabled(value)
       if (result != null && result != "Success.")
         Snackbar.make(activity.findViewById(android.R.id.content), result, Snackbar.LENGTH_LONG).show()
-      value == TcpFastOpen.sendEnabled
+      value == TcpFastOpen.isEnabled
     })
     if (!TcpFastOpen.supported) {
       tfo.setEnabled(false)

src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala

@@ -266,7 +266,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
       cmd += (getApplicationInfo.dataDir + "/acl.list")
     }
 
-    if (TcpFastOpen.sendEnabled) cmd += "--fast-open"
+    if (TcpFastOpen.isEnabled) cmd += "--fast-open"
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd.mkString(" "))
 

src/main/scala/com/github/shadowsocks/utils/Constants.scala

@@ -171,6 +171,8 @@ object Key {
   val kcp = "kcp"
   val kcpPort = "kcpPort"
   val kcpcli = "kcpcli"
+
+  val tfo = "tcp_fastopen"
 }
 
 object State {

src/main/scala/com/github/shadowsocks/utils/TcpFastOpen.scala

@@ -23,28 +23,18 @@ object TcpFastOpen {
     case _ => false
   }
 
-  def sendEnabled = {
+  def isEnabled = {
     val file = new File("/proc/sys/net/ipv4/tcp_fastopen")
     file.canRead && (Utils.readAllLines(file).toInt & 1) > 0
   }
 
-  def enabled(value: Boolean) =
-    Shell.run("su", Array(
+  def enabled(value: Boolean): String = {
+    val res = Shell.run("su", Array(
       "if echo " + (if (value) 3 else 0) + " > /proc/sys/net/ipv4/tcp_fastopen; then",
-      "  success=-1",
-      "  if mount -o rw,remount /dev/block/platform/msm_sdcc.1/by-name/system /system; then",
-      if (value) "    echo '#!/system/bin/sh\n" +
-        "echo 3 > /proc/sys/net/ipv4/tcp_fastopen' > /etc/init.d/tcp_fastopen && chmod 755 /etc/init.d/tcp_fastopen"
-      else "rm -f /etc/init.d/tcp_fastopen",
-      "    success=$?",
-      "    mount -o ro,remount /dev/block/platform/msm_sdcc.1/by-name/system /system",
-      "  fi",
-      "  if [ $success -eq 0 ]; then",
-      "    echo Success.",
-      "  else",
-      "    echo Warning: Unable to create boot script.",
-      "  fi",
+      "  echo Success.",
       "else",
       "  echo Failed.",
-      "fi"), null, true).asScala.mkString("\n")
+      "fi"), null, true)
+    if (res != null) res.asScala.mkString("\n") else null
+  }
 }