From 3213667eead4e77c7cb3c72ac4b0b320b0424f2c Mon Sep 17 00:00:00 2001
From: Jannik Beyerstedt <beyerstedt@consider-it.de>
Date: Mon, 24 Aug 2026 15:16:36 +0200
Subject: [PATCH] BLE: Add service UUID to advertisement, remove descriptors to
 save space

---
 Readme.md  |  3 +++
 src/ble.rs | 21 +++++++++++++--------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/Readme.md b/Readme.md
index 16453c6..97dfd2b 100644
--- a/Readme.md
+++ b/Readme.md
@@ -59,6 +59,9 @@ Enable UART I/O protocol according to [docs/uart-protocol.md](./docs/uart-protoc
 Enable BLE I/O protocol according to [docs/ble-protocol.md](./docs/ble-protocol.md).
 Enabling `denm` feature or `cam` feature is recommended, otherwise no data will be received.
 
+Note: When changing the set of supported messages on the BLE interface, you may need to turn bluetooth off and on again on your client device.
+Otherwise the client may not re-scan the service's characteristics and still use the previous set of characteristics.
+
 
 ## Usage
 
diff --git a/src/ble.rs b/src/ble.rs
index 8fa5ead..bdb32be 100644
--- a/src/ble.rs
+++ b/src/ble.rs
@@ -56,7 +56,7 @@ struct CITSEvents {
     raw_notify: [u8; io::msg::RawNotify::PROTO_SIZE],
 
     #[cfg(feature = "cam")]
-    #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "CAM", read, value = "RawMsgRx proto msg", type = &'static str)]
+    // #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "CAM", read, value = "RawMsgRx proto msg", type = &'static str)]
     #[characteristic(uuid = "c0b70001-d4f4-4003-ada8-f99a02ee315c", read, value = [0u8; io::msg::RawMsgRx::PROTO_SIZE])]
     cam_raw: [u8; io::msg::RawMsgRx::PROTO_SIZE],
     #[cfg(feature = "cam")]
@@ -65,7 +65,7 @@ struct CITSEvents {
     cam_event: [u8; io::msg::CamEvent::PROTO_SIZE],
 
     #[cfg(feature = "denm")]
-    #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "DENM", read, value = "RawMsgRx proto msg", type = &'static str)]
+    // #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "DENM", read, value = "RawMsgRx proto msg", type = &'static str)]
     #[characteristic(uuid = "c0b70001-d4f4-4005-ada8-f99a02ee315c", read, value = [0u8; io::msg::RawMsgRx::PROTO_SIZE])]
     denm_raw: [u8; io::msg::RawMsgRx::PROTO_SIZE],
     #[cfg(feature = "denm")]
@@ -74,11 +74,11 @@ struct CITSEvents {
     denm_event: [u8; io::msg::DenmEvent::PROTO_SIZE],
 
     #[cfg(feature = "spat")]
-    #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "MAPEM", read, value = "RawMsgRx proto msg", type = &'static str)]
+    // #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "MAPEM", read, value = "RawMsgRx proto msg", type = &'static str)]
     #[characteristic(uuid = "c0b70001-d4f4-4007-ada8-f99a02ee315c", read, value = [0u8; io::msg::RawMsgRx::PROTO_SIZE])]
     mapem_raw: [u8; io::msg::RawMsgRx::PROTO_SIZE],
     #[cfg(feature = "spat")]
-    #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "SPATEM", read, value = "RawMsgRx proto msg", type = &'static str)]
+    // #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "SPATEM", read, value = "RawMsgRx proto msg", type = &'static str)]
     #[characteristic(uuid = "c0b70001-d4f4-4008-ada8-f99a02ee315c", read, value = [0u8; io::msg::RawMsgRx::PROTO_SIZE])]
     spatem_raw: [u8; io::msg::RawMsgRx::PROTO_SIZE],
 }
@@ -143,8 +143,10 @@ pub async fn run(
 
     let _ = embassy_futures::join::join(ble_task(runner), async {
         loop {
-            match advertise("ESP32 C-ITS", &mut peripheral, &server).await {
+            match advertise(&mut peripheral, &server).await {
                 Ok(conn) => {
+                    info!("BLE: New client connected");
+
                     // set up tasks when the connection is established to a central, so they don't run when no one is connected.
                     let a = gatt_events_task(&server, &conn);
                     let b = publishing_task(&server, &conn);
@@ -158,7 +160,7 @@ pub async fn run(
                     });
                 }
                 Err(e) => {
-                    panic!("BLE ADV: fatal error {e:?}");
+                    panic!("BLE ADV: fatal error: {e:?}");
                 }
             }
         }
@@ -183,15 +185,18 @@ pub fn update(payload: BleSendable) {
 
 /// Create an advertiser to use to connect to a BLE Central, and wait for it to connect.
 async fn advertise<'values, 'server, C: Controller>(
-    name: &'values str,
     peripheral: &mut Peripheral<'values, C, DefaultPacketPool>,
     server: &'server Server<'values>,
 ) -> Result<GattConnection<'values, 'server, DefaultPacketPool>, BleHostError<C::Error>> {
     let mut advertiser_data = [0; 35];
+    let service_uuid = Uuid::from(0xc0b7_0000_d4f4_4000_ada8_f99a_02ee_315c_u128)
+        .as_raw()
+        .try_into()
+        .unwrap();
     let len = AdStructure::encode_slice(
         &[
             AdStructure::Flags(LE_GENERAL_DISCOVERABLE | BR_EDR_NOT_SUPPORTED),
-            AdStructure::CompleteLocalName(name.as_bytes()),
+            AdStructure::ServiceUuids128(&[service_uuid]),
         ],
         &mut advertiser_data[..],
     )?;