From ba057f0092fa6ce8c86cdb49096d3204352dc914 Mon Sep 17 00:00:00 2001
From: hacklab <hacklab@noreply.gitea.laenre.net>
Date: Sat, 10 Oct 2026 15:54:42 +0200
Subject: [PATCH] android: permisos y MulticastLock para ver moviles en la
 misma wifi

El anuncio LAN de SSB va por UDP broadcast y Android lo filtra sin un
MulticastLock. La oficial declara ACCESS_WIFI_STATE y
CHANGE_WIFI_MULTICAST_STATE; esta no, asi que dos moviles en la misma red no
se encontraban.
---
 android/app/src/main/AndroidManifest.xml      |  4 ++++
 .../main/java/net/laenre/oasis/NodeService.kt | 22 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/android/app/src/main/AndroidManifest.xml b/android/app/src/main/AndroidManifest.xml
index edcd992..22102a4 100644
--- a/android/app/src/main/AndroidManifest.xml
+++ b/android/app/src/main/AndroidManifest.xml
@@ -3,6 +3,10 @@
 
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+  <!-- descubrir otros moviles en la misma wifi: el anuncio LAN de SSB va por UDP
+       broadcast/multicast, y Android lo filtra si no se coge un MulticastLock -->
+  <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
+  <uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
   <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
   <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
   <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
diff --git a/android/app/src/main/java/net/laenre/oasis/NodeService.kt b/android/app/src/main/java/net/laenre/oasis/NodeService.kt
index 9bd6f07..f7796ee 100644
--- a/android/app/src/main/java/net/laenre/oasis/NodeService.kt
+++ b/android/app/src/main/java/net/laenre/oasis/NodeService.kt
@@ -6,6 +6,7 @@ import android.app.NotificationManager
 import android.app.Service
 import android.content.Context
 import android.content.Intent
+import android.net.wifi.WifiManager
 import android.os.Build
 import android.os.IBinder
 import android.system.Os
@@ -33,16 +34,37 @@ class NodeService : Service() {
     @Volatile private var started = false
   }
 
+  // Sin esto Android tira los paquetes multicast/broadcast que llegan por wifi y el
+  // descubrimiento LAN de SSB no ve a nadie: dos moviles en la misma red no se encuentran.
+  private var multicastLock: WifiManager.MulticastLock? = null
+
   override fun onBind(intent: Intent?): IBinder? = null
 
   override fun onCreate() {
     super.onCreate()
     startForeground(NOTIF_ID, buildNotification())
+    acquireMulticastLock()
     if (started) return
     started = true
     Thread({ runNode() }, "node-main").start()
   }
 
+  override fun onDestroy() {
+    try { multicastLock?.takeIf { it.isHeld }?.release() } catch (e: Throwable) { Log.w(TAG, "soltando MulticastLock", e) }
+    super.onDestroy()
+  }
+
+  private fun acquireMulticastLock() {
+    if (multicastLock?.isHeld == true) return
+    try {
+      val wifi = applicationContext.getSystemService(Context.WIFI_SERVICE) as WifiManager
+      multicastLock = wifi.createMulticastLock("oasis-lan").apply { setReferenceCounted(false); acquire() }
+    } catch (e: Throwable) {
+      // sin wifi o sin permiso: los pubs siguen funcionando, solo se pierde la LAN
+      Log.w(TAG, "no se ha podido coger el MulticastLock; sin descubrimiento LAN", e)
+    }
+  }
+
   private fun buildNotification(): Notification {
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
       val ch = NotificationChannel(CHANNEL, getString(R.string.node_channel), NotificationManager.IMPORTANCE_LOW)