feat(clients): Wake-on-LAN in apple/linux/windows/android/decky

Each client learns a host's MAC from the mDNS `mac` TXT while it's awake, persists it on the saved-host record, and — when reconnecting to an offline host — sends a magic packet before connecting, plus an explicit "Wake host" action. Apple wraps the C-ABI; linux/windows call the core fn directly (linux also gains a --wake CLI mode); android via a new nativeWakeOnLan JNI export (the mDNS browse record gains a 7th mac field); decky shells out to the linux client's --wake before launching the stream.

iOS/tvOS need the managed com.apple.developer.networking.multicast entitlement (pending Apple approval), so the wake path + UI are gated off via PunktfunkConnection.wakeOnLANAvailable and the entitlement is commented out — keeping iOS/tvOS releasable. MAC-learning stays active on every platform so it lights up the moment it's ungated. macOS works today.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/android/app/src/main/kotlin/io/unom/punktfunk/ConnectScreen.kt

@@ -124,6 +124,25 @@ fun ConnectScreen(settings: Settings, onConnected: (Long) -> Unit) {
     val identityStore = remember { IdentityStore(context) }
     val knownHostStore = remember { KnownHostStore(context) }
     var savedHosts by remember { mutableStateOf(knownHostStore.all()) }
+    // Learn wake MAC(s) from live adverts for hosts we've saved (parity with the desktop clients),
+    // so we can Wake-on-LAN them once they sleep. Runs only when the discovered set changes; the
+    // prefs write is guarded (no-op when unchanged), and we refresh the saved list only if a MAC
+    // was actually newly learned.
+    LaunchedEffect(discovered) {
+        val learned = withContext(Dispatchers.IO) {
+            var any = false
+            discovered.forEach { dh ->
+                if (dh.mac.isNotEmpty() &&
+                    knownHostStore.get(dh.host, dh.port)?.let { it.mac != dh.mac } == true
+                ) {
+                    knownHostStore.learnMac(dh.host, dh.port, dh.mac)
+                    any = true
+                }
+            }
+            any
+        }
+        if (learned) savedHosts = knownHostStore.all()
+    }
     // Mint-once on genuine first run; an Unrecoverable store (decrypt failure) surfaces here and
     // refuses to connect — never silently shadow-minting a new identity (which would force re-pair).
     var identity by remember { mutableStateOf<ClientIdentity?>(null) }
@@ -176,6 +195,14 @@ fun ConnectScreen(settings: Settings, onConnected: (Long) -> Unit) {
         }
         connecting = true
         status = "Connecting to $targetHost:$targetPort…"
+        // Auto-wake: reconnecting to a saved host that may be asleep. If we learned its MAC while it
+        // was online and it isn't currently advertising, fire a magic packet first — the connect's
+        // own timeout gives a woken host time to come up (harmless if it's already awake).
+        knownHostStore.get(targetHost, targetPort)?.mac
+            ?.takeIf { it.isNotEmpty() && discovered.none { d -> d.host == targetHost && d.port == targetPort } }
+            ?.let { macs ->
+                scope.launch(Dispatchers.IO) { NativeBridge.nativeWakeOnLan(macs.joinToString(","), targetHost) }
+            }
         discovery.stop() // free the Wi-Fi radio before the stream session
         scope.launch {
             val handle = connectNative(id, targetHost, targetPort, pinHex ?: "", CONNECT_TIMEOUT_MS)
@@ -359,6 +386,15 @@ fun ConnectScreen(settings: Settings, onConnected: (Long) -> Unit) {
                             savedHosts = knownHostStore.all()
                         },
                         onRename = { renameTarget = kh },
+                        // Explicit wake: offered only when the host is offline and we have a MAC to
+                        // target (a tap-to-connect already auto-wakes an offline saved host).
+                        onWake = if (kh.mac.isNotEmpty() &&
+                            discovered.none { it.host == kh.address && it.port == kh.port }
+                        ) {
+                            { scope.launch(Dispatchers.IO) { NativeBridge.nativeWakeOnLan(kh.mac.joinToString(","), kh.address) } }
+                        } else {
+                            null
+                        },
                     )
                 }
             }

clients/android/app/src/main/kotlin/io/unom/punktfunk/components/HostComponents.kt

@@ -60,6 +60,7 @@ fun HostCard(
     onConnect: () -> Unit,
     onForget: (() -> Unit)?,
     onRename: (() -> Unit)? = null,
+    onWake: (() -> Unit)? = null,
 ) {
     // D-pad / controller focus highlight: a clickable card is focusable, but the default state
     // layer is too subtle on a TV across a room — draw a clear primary-colour border when focused.
@@ -107,7 +108,7 @@ fun HostCard(
                 StatusPill(status)
             }
 
-            if (onForget != null || onRename != null) {
+            if (onForget != null || onRename != null || onWake != null) {
                 var menu by remember { mutableStateOf(false) }
                 Box(modifier = Modifier.align(Alignment.TopEnd)) {
                     IconButton(enabled = enabled, onClick = { menu = true }) {
@@ -119,6 +120,15 @@ fun HostCard(
                         )
                     }
                     DropdownMenu(expanded = menu, onDismissRequest = { menu = false }) {
+                        if (onWake != null) {
+                            DropdownMenuItem(
+                                text = { Text("Wake host") },
+                                onClick = {
+                                    menu = false
+                                    onWake()
+                                },
+                            )
+                        }
                         if (onRename != null) {
                             DropdownMenuItem(
                                 text = { Text("Rename") },

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/NativeBridge.kt

@@ -86,7 +86,7 @@ object NativeBridge {
 
     /**
      * The current resolved-host snapshot for [handle]: newline-joined records, each
-     * `key␟name␟addr␟port␟fp␟pair` (`␟` = U+001F). Empty string = no hosts / `0` handle. Poll ~1 Hz;
+     * `key␟name␟addr␟port␟fp␟pair␟mac` (`␟` = U+001F). Empty string = no hosts / `0` handle. Poll ~1 Hz;
      * cheap (a lock + string build), safe to call on the main thread.
      */
     external fun nativeDiscoveryPoll(handle: Long): String
@@ -94,6 +94,15 @@ object NativeBridge {
     /** Stop the browse, shut the mDNS daemon down and join its thread. No-op on `0`. */
     external fun nativeDiscoveryStop(handle: Long)
 
+    /**
+     * Send a Wake-on-LAN magic packet to wake a sleeping host. [macsCsv] is comma-separated MAC
+     * addresses (`aa:bb:..,cc:dd:..`), learned from the host's mDNS `mac` TXT while it was online;
+     * [lastIp] is the host's last-known IPv4 (or empty). Returns true if at least one datagram was
+     * sent. No handle — callable without a live session. Do NOT call on the main thread (it does
+     * blocking socket sends); run it on a background dispatcher.
+     */
+    external fun nativeWakeOnLan(macsCsv: String, lastIp: String): Boolean
+
     /**
      * Start the HEVC decode thread rendering onto [surface] (a SurfaceView's surface). Decode runs
      * entirely in Rust (NDK AMediaCodec → ANativeWindow) — no per-frame JNI. No-op if already started.

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/discovery/HostDiscovery.kt

@@ -17,15 +17,17 @@ data class DiscoveredHost(
     val port: Int,
     val fingerprint: String? = null, // TXT "fp" (host cert SHA-256, advisory — TOFU still verifies)
     val pairingRequired: Boolean = false,
+    val mac: List<String> = emptyList(), // TXT "mac" (wake-capable NIC MAC(s), for Wake-on-LAN)
 )
 
 /** Field separator the native browse uses inside one record (ASCII Unit Separator). */
 private const val FIELD_SEP = '\u001F'
 
 /**
- * Parse one record from [NativeBridge.nativeDiscoveryPoll] (`key␟name␟addr␟port␟fp␟pair`), or null
- * if it's malformed. Pure — unit-tested without Android (see ParseRecordTest). The native side
- * already applied the protocol gate and address selection, so this is just field marshaling.
+ * Parse one record from [NativeBridge.nativeDiscoveryPoll] (`key␟name␟addr␟port␟fp␟pair␟mac`), or
+ * null if it's malformed. `mac` (7th field) is optional — an older host omits it. Pure —
+ * unit-tested without Android (see ParseRecordTest). The native side already applied the protocol
+ * gate and address selection, so this is just field marshaling.
  */
 fun parseHostRecord(record: String): DiscoveredHost? {
     val f = record.split(FIELD_SEP)
@@ -40,6 +42,8 @@ fun parseHostRecord(record: String): DiscoveredHost? {
         port = port,
         fingerprint = f[4].ifBlank { null },
         pairingRequired = f[5] == "required",
+        mac = if (f.size > 6) f[6].split(",").map { it.trim() }.filter { it.isNotEmpty() }
+        else emptyList(),
     )
 }
 

clients/android/kit/src/main/kotlin/io/unom/punktfunk/kit/security/KnownHostStore.kt

@@ -13,6 +13,11 @@ data class KnownHost(
     val name: String,
     val fpHex: String,
     val paired: Boolean,
+    /**
+     * Wake-on-LAN MAC(s) (`aa:bb:cc:dd:ee:ff`) learned from the host's mDNS `mac` TXT while it was
+     * online, so the client can wake it once it sleeps. Empty until first learned.
+     */
+    val mac: List<String> = emptyList(),
 )
 
 /**
@@ -42,9 +47,22 @@ class KnownHostStore(context: Context) {
             .put("name", host.name)
             .put("fp", host.fpHex.lowercase())
             .put("paired", host.paired)
+            .put("mac", host.mac.joinToString(","))
         prefs.edit().putString(key(host.address, host.port), json.toString()).apply()
     }
 
+    /**
+     * Learn/refresh a saved host's Wake-on-LAN MAC(s) from its live advert (called while online).
+     * No-op when the host isn't saved, the list is empty, or it's unchanged — so it doesn't churn
+     * prefs on every discovery tick.
+     */
+    fun learnMac(address: String, port: Int, mac: List<String>) {
+        if (mac.isEmpty()) return
+        val h = get(address, port) ?: return
+        if (h.mac == mac) return
+        save(h.copy(mac = mac))
+    }
+
     /** Forget [address]:[port] (the next connect re-pairs / re-TOFUs). */
     fun remove(address: String, port: Int) {
         prefs.edit().remove(key(address, port)).apply()
@@ -68,6 +86,7 @@ class KnownHostStore(context: Context) {
             name = j.getString("name"),
             fpHex = j.getString("fp"),
             paired = j.optBoolean("paired", false),
+            mac = j.optString("mac", "").split(",").map { it.trim() }.filter { it.isNotEmpty() },
         )
     }.getOrNull()
 }

clients/android/native/src/discovery.rs

@@ -31,7 +31,7 @@ const PROTO: &str = "punktfunk/1";
 /// Field separator inside one serialized record (ASCII Unit Separator — never in a field value).
 const FIELD_SEP: char = '\u{1f}';
 
-/// One resolved host, serialized to Kotlin as `key␟name␟addr␟port␟fp␟pair` (`␟` = [`FIELD_SEP`]).
+/// One resolved host, serialized to Kotlin as `key␟name␟addr␟port␟fp␟pair␟mac` (`␟` = [`FIELD_SEP`]).
 /// Records are newline-joined in a poll snapshot; [`Host::encode`] strips the framing bytes from
 /// every field so no value can break it.
 #[derive(Clone, PartialEq)]
@@ -42,6 +42,8 @@ struct Host {
     port: u16,
     fp: String,
     pair: String,
+    /// Wake-on-LAN MAC(s) from the mDNS `mac` TXT (comma-separated), for later wake. Empty if absent.
+    mac: String,
 }
 
 impl Host {
@@ -54,13 +56,14 @@ impl Host {
             s.replace(['\n', '\r', FIELD_SEP], "")
         }
         format!(
-            "{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}",
+            "{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}{FIELD_SEP}{}",
             clean(&self.key),
             clean(&self.name),
             clean(&self.addr),
             self.port,
             clean(&self.fp),
             clean(&self.pair),
+            clean(&self.mac),
         )
     }
 }
@@ -182,6 +185,7 @@ fn resolve(info: &ResolvedService) -> Option<Host> {
         port: info.get_port(),
         fp: val("fp"),
         pair: val("pair"),
+        mac: val("mac"),
     })
 }
 
@@ -202,7 +206,7 @@ pub extern "system" fn Java_io_unom_punktfunk_kit_NativeBridge_nativeDiscoverySt
 }
 
 /// `NativeBridge.nativeDiscoveryPoll(handle): String` — the current resolved-host snapshot,
-/// newline-joined records of `key␟name␟addr␟port␟fp␟pair` (`␟` = U+001F). Empty string = no hosts /
+/// newline-joined records of `key␟name␟addr␟port␟fp␟pair␟mac` (`␟` = U+001F). Empty string = no hosts /
 /// `0` handle. Poll ~1 Hz from the UI thread (cheap: a mutex lock + string build).
 #[no_mangle]
 pub extern "system" fn Java_io_unom_punktfunk_kit_NativeBridge_nativeDiscoveryPoll<'local>(
@@ -263,16 +267,18 @@ mod tests {
             port: 9777,
             fp: "ab".repeat(32),
             pair: "required".into(),
+            mac: "aa:bb:cc:dd:ee:ff".into(),
         };
         let encoded = h.encode();
         let fields: Vec<&str> = encoded.split(FIELD_SEP).collect();
-        assert_eq!(fields.len(), 6);
+        assert_eq!(fields.len(), 7);
         assert_eq!(fields[0], "host-123");
         assert_eq!(fields[1], "home-worker-2");
         assert_eq!(fields[2], "192.168.1.70");
         assert_eq!(fields[3], "9777");
         assert_eq!(fields[4], "ab".repeat(32));
         assert_eq!(fields[5], "required");
+        assert_eq!(fields[6], "aa:bb:cc:dd:ee:ff");
         assert!(
             !encoded.contains('\n'),
             "a record must never contain the record separator"
@@ -282,7 +288,7 @@ mod tests {
     #[test]
     fn encode_strips_injected_separators_from_a_hostile_advert() {
         // A rogue advert could carry framing bytes in its instance label / TXT; encode must strip
-        // them so the snapshot stays exactly one record of exactly six fields.
+        // them so the snapshot stays exactly one record of exactly seven fields.
         let h = Host {
             key: "k\u{1f}injected".into(),
             name: "evil\nhost\r".into(),
@@ -290,9 +296,10 @@ mod tests {
             port: 9777,
             fp: "ab\u{1f}cd".into(),
             pair: "required\n".into(),
+            mac: "aa:bb\u{1f}cc".into(),
         };
         let encoded = h.encode();
-        assert_eq!(encoded.matches(FIELD_SEP).count(), 5, "exactly six fields");
+        assert_eq!(encoded.matches(FIELD_SEP).count(), 6, "exactly seven fields");
         assert!(!encoded.contains('\n') && !encoded.contains('\r'));
         let fields: Vec<&str> = encoded.split(FIELD_SEP).collect();
         assert_eq!(fields[0], "kinjected");

clients/android/native/src/lib.rs

@@ -39,6 +39,9 @@ mod feedback;
 mod mic;
 mod session;
 mod stats;
+// Ungated like `discovery`: pure `jni` + `punktfunk_core::wol` (no Android framework), so it links
+// into the host workspace build too. Kotlin only ever calls it on device.
+mod wol;
 
 /// Initialize `android_logger` once when the JVM loads the library. Logs land in logcat under the
 /// `punktfunk` tag. Android-only — there is no JVM (and no logcat) on the host build.

clients/android/native/src/wol.rs

@@ -0,0 +1,40 @@
+//! JNI seam for Wake-on-LAN: parse the stored MAC strings and hand them to the shared core sender
+//! (`punktfunk_core::wol`). Like [`crate::discovery`], this takes no session handle — a sleeping
+//! host has no ARP entry, so the broadcast the core sends is what wakes it, and Kotlin calls this
+//! just before connecting to an offline saved host.
+
+use jni::objects::{JObject, JString};
+use jni::JNIEnv;
+
+/// `NativeBridge.nativeWakeOnLan(macsCsv: String, lastIp: String): Boolean` — send a Wake-on-LAN
+/// magic packet. `macsCsv` is comma-separated MACs (`aa:bb:..,cc:dd:..`, learned from the host's
+/// mDNS `mac` TXT while it was online); `lastIp` is the host's last-known IPv4 (or empty).
+/// Returns true if at least one datagram went out.
+#[no_mangle]
+pub extern "system" fn Java_io_unom_punktfunk_kit_NativeBridge_nativeWakeOnLan<'local>(
+    mut env: JNIEnv<'local>,
+    _this: JObject<'local>,
+    macs_csv: JString<'local>,
+    last_ip: JString<'local>,
+) -> jni::sys::jboolean {
+    let macs_csv: String = match env.get_string(&macs_csv) {
+        Ok(s) => s.into(),
+        Err(_) => return 0,
+    };
+    let last_ip: String = env
+        .get_string(&last_ip)
+        .map(|s| Into::<String>::into(s))
+        .unwrap_or_default();
+    let macs: Vec<[u8; 6]> = macs_csv
+        .split(',')
+        .filter_map(|s| punktfunk_core::wol::parse_mac(s.trim()))
+        .collect();
+    if macs.is_empty() {
+        return 0;
+    }
+    let ip = last_ip.trim().parse::<std::net::Ipv4Addr>().ok();
+    match punktfunk_core::wol::send_magic_packet(&macs, ip) {
+        Ok(()) => 1,
+        Err(_) => 0,
+    }
+}