feat: resend broadcast mdns if nearby sharing

Signed-off-by: Martichou <m@rtin.fyi>

Cargo.toml

@@ -16,7 +16,7 @@ hmac = "0.12"
 libaes = "0.7"
 local-ip-address = "0.5"
 log = "0.4"
-mdns-sd = "0.10"
+mdns-sd = { git = "https://github.com/Martichou/mdns-sd", branch = "unsolicited" }
 once_cell = "1.0"
 open = "5.0"
 p256 = { version = "0.13", features = ["ecdh"] }

src/backend/ble.rs

@@ -1,4 +1,3 @@
-use std::collections::HashMap;
 use std::time::{Duration, SystemTime};
 
 use anyhow::anyhow;
@@ -42,7 +41,7 @@ impl BleListener {
             })
             .await?;
 
-        let mut already_alerted = HashMap::new();
+        let mut last_alert = SystemTime::now();
 
         loop {
             tokio::select! {
@@ -53,20 +52,18 @@ impl BleListener {
                 Some(e) = events.next() => {
                     match e {
                         CentralEvent::ServiceDataAdvertisement { id, service_data } => {
+                            let _ = id;
                             let _ = service_data;
                             let now = SystemTime::now();
-                            let when = already_alerted.get(&id);
 
-                            // Don't spam, max once per 60s
-                            if let Some(t) = when {
-                                if now.duration_since(*t)? <= Duration::from_secs(60) {
-                                    continue;
-                                }
+                            // Don't spam, max once per 15s
+                            if now.duration_since(last_alert)? <= Duration::from_secs(15) {
+                                continue;
                             }
 
                             debug!("{INNER_NAME}: A device is sharing nearby");
                             self.sender.send(())?;
-                            already_alerted.insert(id, now);
+                            last_alert = now;
                         },
                         // Not interesting for us
                         _ => {

src/backend/mdns.rs

@@ -44,11 +44,11 @@ impl MDnsServer {
         device_type: DeviceType,
         receiver: Receiver<()>,
     ) -> Result<Self, anyhow::Error> {
-        let service = Self::build_service(service_port, device_type)?;
-        let fullname = service.get_fullname().to_owned();
+        let service_info = Self::build_service(service_port, device_type)?;
+        let fullname = service_info.get_fullname().to_owned();
 
         let daemon = ServiceDaemon::new()?;
-        daemon.register(service)?;
+        daemon.register(service_info)?;
 
         Ok(Self {
             daemon,
@@ -77,7 +77,12 @@ impl MDnsServer {
                 // Can be used later on to change the visibility on the fly
                 // by unregistering the service and registering it only when
                 // a device nearby is sharing.
-                _ = receiver.recv() => {}
+                _ = receiver.recv() => {
+                    // Android can sometime not see the mDNS service if the service
+                    // was running BEFORE Android started the Discovery phase for QuickShare.
+                    // So resend a broadcast if there's a android device sending.
+                    self.daemon.register_resend(&self.fullname)?;
+                }
             }
         }