From b93bf5513a1c43ac11acef409c81dc7238324d69 Mon Sep 17 00:00:00 2001
From: pacien
Date: Wed, 26 Sep 2018 00:36:40 +0200
Subject: Trigger tinc reconnection on network state change

---
 .../main/java/org/pacien/tincapp/commands/Tinc.kt  |  4 ++
 .../tincapp/service/ConnectivityChangeReceiver.kt  | 60 ++++++++++++++++++++++
 .../org/pacien/tincapp/service/TincVpnService.kt   |  6 +++
 3 files changed, 70 insertions(+)
 create mode 100644 app/src/main/java/org/pacien/tincapp/service/ConnectivityChangeReceiver.kt

diff --git a/app/src/main/java/org/pacien/tincapp/commands/Tinc.kt b/app/src/main/java/org/pacien/tincapp/commands/Tinc.kt
index 4d00805..dc23935 100644
--- a/app/src/main/java/org/pacien/tincapp/commands/Tinc.kt
+++ b/app/src/main/java/org/pacien/tincapp/commands/Tinc.kt
@@ -34,6 +34,10 @@ object Tinc {
     Executor.call(newCommand(netName).withArguments("stop"))
       .thenApply { }
 
+  fun retry(netName: String): CompletableFuture<Unit> =
+    Executor.call(newCommand(netName).withArguments("retry"))
+      .thenApply { }
+
   fun pid(netName: String): CompletableFuture<Int> =
     Executor.call(newCommand(netName).withArguments("pid"))
       .thenApply { Integer.parseInt(it.first()) }
diff --git a/app/src/main/java/org/pacien/tincapp/service/ConnectivityChangeReceiver.kt b/app/src/main/java/org/pacien/tincapp/service/ConnectivityChangeReceiver.kt
new file mode 100644
index 0000000..ba9aa95
--- /dev/null
+++ b/app/src/main/java/org/pacien/tincapp/service/ConnectivityChangeReceiver.kt
@@ -0,0 +1,60 @@
+/*
+ * Tinc App, an Android binding and user interface for the tinc mesh VPN daemon
+ * Copyright (C) 2017-2018 Pacien TRAN-GIRARD
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+
+package org.pacien.tincapp.service
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.net.ConnectivityManager
+import org.pacien.tincapp.commands.Tinc
+import org.slf4j.LoggerFactory
+
+/**
+ * @author pacien
+ */
+object ConnectivityChangeReceiver : BroadcastReceiver() {
+  private val log by lazy { LoggerFactory.getLogger(this.javaClass)!! }
+  private val tincCtl = Tinc
+  private val tincVpnService = TincVpnService
+
+  override fun onReceive(context: Context, intent: Intent) {
+    log.info("Connectivity change intent received: {}", intent.toString())
+    if (isNetworkAvailable(intent)) attemptReconnect()
+  }
+
+  private fun attemptReconnect() {
+    tincVpnService.getCurrentNetName()?.let { netName ->
+      log.info("Sending immediate reconnection request to the tinc daemon.")
+      tincCtl.retry(netName)
+    }
+  }
+
+  private fun isNetworkAvailable(intent: Intent) =
+    !intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false)
+
+  fun registerWatcher(context: Context) {
+    val filter = IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION)
+    context.registerReceiver(this, filter)
+  }
+
+  fun unregisterWatcher(context: Context) {
+    context.unregisterReceiver(this)
+  }
+}
diff --git a/app/src/main/java/org/pacien/tincapp/service/TincVpnService.kt b/app/src/main/java/org/pacien/tincapp/service/TincVpnService.kt
index 45058e2..28f1347 100644
--- a/app/src/main/java/org/pacien/tincapp/service/TincVpnService.kt
+++ b/app/src/main/java/org/pacien/tincapp/service/TincVpnService.kt
@@ -49,6 +49,7 @@ import java.io.FileNotFoundException
  */
 class TincVpnService : VpnService() {
   private val log by lazy { LoggerFactory.getLogger(this.javaClass)!! }
+  private val connectivityChangeReceiver = ConnectivityChangeReceiver
 
   override fun onDestroy() {
     stopVpn()
@@ -150,11 +151,16 @@ class TincVpnService : VpnService() {
         log.info("tinc daemon started.")
         broadcastEvent(Actions.EVENT_CONNECTED)
       }
+
+      connectivityChangeReceiver.registerWatcher(this)
     }
   }
 
   private fun stopVpn(): Unit = synchronized(this) {
     log.info("Stopping any running tinc daemon.")
+
+    connectivityChangeReceiver.unregisterWatcher(this)
+
     getCurrentNetName()?.let {
       Tinc.stop(it).thenRun {
         log.info("All tinc daemons stopped.")
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