From 8e6bea372a98312fa8a443f17e2311645fc61efd Mon Sep 17 00:00:00 2001 From: Jannik Beyerstedt Date: Tue, 18 Aug 2026 17:11:31 +0200 Subject: [PATCH] BLE: Add "service change attribute", advertise service --- src/ble.rs | 87 ++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 75 insertions(+), 12 deletions(-) diff --git a/src/ble.rs b/src/ble.rs index 8fa5ead..9546519 100644 --- a/src/ble.rs +++ b/src/ble.rs @@ -39,11 +39,69 @@ pub enum BleSendable { SpatemRaw(io::msg::RawMsgRx), } -#[gatt_server] -struct Server { +// GAP + 4 GATT attributes + our service(s) +const _ATTRIBUTE_TABLE_SIZE: usize = GAP_SERVICE_ATTRIBUTE_COUNT + 4 + CITSEvents::ATTRIBUTE_COUNT; + +pub struct Server<'values> { + server: AttributeServer< + 'values, + embassy_sync::blocking_mutex::raw::NoopRawMutex, + DefaultPacketPool, + _ATTRIBUTE_TABLE_SIZE, + 1, + CONNECTIONS_MAX, + >, c_its_events: CITSEvents, } +impl<'values> Server<'values> { + // we implement this ourselves to add the "SERVICE_CHANGED" GATT characteristic, + // otherwise client devices won't update the service's characteristics when they change. + fn new_with_config(config: PeripheralConfig<'values>) -> Result { + let mut table: AttributeTable< + '_, + embassy_sync::blocking_mutex::raw::NoopRawMutex, + _ATTRIBUTE_TABLE_SIZE, + > = AttributeTable::new(); + + // manual implementation of: gap.build(&mut table)?; + if !config.name.is_ascii() || config.name.len() > 22 { + return Err("Device name is too long. Max length is 22 bytes"); + } + + let mut gap_builder = table.add_service(Service::new(service::GAP)); + gap_builder.add_characteristic_ro(characteristic::DEVICE_NAME, config.name.as_bytes()); + gap_builder.add_characteristic_ro(characteristic::APPEARANCE, config.appearance); + gap_builder.build(); + + // add custom GATT service + let mut gatt_builder = table.add_service(Service::new(service::GATT)); + gatt_builder.add_characteristic_ro(characteristic::SERVICE_CHANGED, &[1, 0, 255, 255]); // [0x0001, 0xFFFF] in little-endian + gatt_builder.build(); + + let c_its_events = CITSEvents::new(&mut table); + + Ok(Self { + server: AttributeServer::new(table), + c_its_events, + }) + } +} + +impl<'values> core::ops::Deref for Server<'values> { + type Target = AttributeServer< + 'values, + embassy_sync::blocking_mutex::raw::NoopRawMutex, + DefaultPacketPool, + _ATTRIBUTE_TABLE_SIZE, + 1, + CONNECTIONS_MAX, + >; + fn deref(&self) -> &Self::Target { + &self.server + } +} + #[gatt_service(uuid = "c0b70000-d4f4-4000-ada8-f99a02ee315c")] struct CITSEvents { #[descriptor(uuid = descriptors::MEASUREMENT_DESCRIPTION, name = "Position", read, value = "PositionState proto msg", type = &'static str)] @@ -56,7 +114,7 @@ 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 +123,7 @@ 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 +132,11 @@ 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], } @@ -135,16 +193,18 @@ pub async fn run( "Starting advertising and GATT service for {}", features.join(",") ); - let server = Server::new_with_config(GapConfig::Peripheral(PeripheralConfig { + let server = Server::new_with_config(PeripheralConfig { name: &name, appearance: &appearance::UNKNOWN, - })) + }) .unwrap(); 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 +218,7 @@ pub async fn run( }); } Err(e) => { - panic!("BLE ADV: fatal error {e:?}"); + panic!("BLE ADV: fatal error: {e:?}"); } } } @@ -183,15 +243,18 @@ 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, BleHostError> { 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[..], )?;