Bluetooth: add destroy callback to indication

Adds a `destroy` callback to the `struct bt_gatt_indicate_params` which
is used to signify to the application that the indication operation has
completed and the struct instance can be freed/destroyed.

This is required as the number of indication value callbacks that will
be triggered is not known by the caller when the `conn` parameter is
`NULL`.

Tracking when this callback should be run is mananged by a private
reference counter inside the struct.

Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>

include/bluetooth/gatt.h

@@ -1013,6 +1013,9 @@ typedef void (*bt_gatt_indicate_func_t)(struct bt_conn *conn,
 					struct bt_gatt_indicate_params *params,
 					uint8_t err);
 
+typedef void (*bt_gatt_indicate_params_destroy_t)(
+		struct bt_gatt_indicate_params *params);
+
 /** @brief GATT Indicate Value parameters */
 struct bt_gatt_indicate_params {
 	/** Notification Attribute UUID type */
@@ -1021,10 +1024,14 @@ struct bt_gatt_indicate_params {
 	const struct bt_gatt_attr *attr;
 	/** Indicate Value callback */
 	bt_gatt_indicate_func_t func;
+	/** Indicate operation complete callback */
+	bt_gatt_indicate_params_destroy_t destroy;
 	/** Indicate Value data*/
 	const void *data;
 	/** Indicate Value length*/
 	uint16_t len;
+	/** Private reference counter */
+	uint8_t _ref;
 };
 
 /** @brief Indicate attribute value change.
@@ -1046,7 +1053,8 @@ struct bt_gatt_indicate_params {
  *  start range when looking up for possible matches.
  *
  *  @note This procedure is asynchronous therefore the parameters need to
- *        remains valid while it is active.
+ *        remains valid while it is active. The procedure is active until
+ *        the destroy callback is run.
  *
  *  @param conn Connection object.
  *  @param params Indicate parameters.

samples/bluetooth/peripheral/src/main.c

@@ -356,6 +356,7 @@ void main(void)
 
 			ind_params.attr = &vnd_svc.attrs[2];
 			ind_params.func = indicate_cb;
+			ind_params.destroy = NULL;
 			ind_params.data = &indicating;
 			ind_params.len = sizeof(indicating);
 

samples/bluetooth/peripheral_ht/src/hts.c

@@ -117,6 +117,7 @@ gatt_indicate:
 
 		ind_params.attr = &hts_svc.attrs[2];
 		ind_params.func = indicate_cb;
+		ind_params.destroy = NULL;
 		ind_params.data = &htm;
 		ind_params.len = sizeof(htm);
 

subsys/bluetooth/host/gatt.c

@@ -1900,7 +1900,11 @@ static void gatt_indicate_rsp(struct bt_conn *conn, uint8_t err,
 {
 	struct bt_gatt_indicate_params *params = user_data;
 
+	params->_ref--;
 	params->func(conn, params, err);
+	if (params->destroy && (params->_ref == 0)) {
+		params->destroy(params);
+	}
 }
 
 static int gatt_send(struct bt_conn *conn, struct net_buf *buf,
@@ -2056,6 +2060,9 @@ static uint8_t notify_cb(const struct bt_gatt_attr *attr, uint16_t handle,
 		if (data->type == BT_GATT_CCC_INDICATE) {
 			err = gatt_indicate(conn, data->handle,
 					    data->ind_params);
+			if (err == 0) {
+				data->ind_params->_ref++;
+			}
 		} else {
 			err = gatt_notify(conn, data->handle, data->nfy_params);
 		}
@@ -2212,6 +2219,7 @@ int bt_gatt_indicate(struct bt_conn *conn,
 	}
 
 	if (conn) {
+		params->_ref = 1;
 		return gatt_indicate(conn, data.handle, params);
 	}
 
@@ -2219,6 +2227,7 @@ int bt_gatt_indicate(struct bt_conn *conn,
 	data.type = BT_GATT_CCC_INDICATE;
 	data.ind_params = params;
 
+	params->_ref = 0;
 	bt_gatt_foreach_attr_type(data.handle, 0xffff, BT_UUID_GATT_CCC, NULL,
 				  1, notify_cb, &data);
 

tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/gatt/service_b_3_2.c

@@ -168,6 +168,7 @@ void service_b_3_2_value_v6_indicate(void)
 	 */
 	ind_params.attr = &service_b_3_2_attrs[2];
 	ind_params.func = value_v6_indicate_cb;
+	ind_params.destroy = NULL;
 	ind_params.data = &value_v6_value;
 	ind_params.len = sizeof(value_v6_value);
 

tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/gatt/service_b_3_3.c

@@ -168,6 +168,7 @@ void service_b_3_3_value_v6_indicate(void)
 	 */
 	ind_params.attr = &service_b_3_3_attrs[2];
 	ind_params.func = value_v6_indicate_cb;
+	ind_params.destroy = NULL;
 	ind_params.data = &value_v6_value;
 	ind_params.len = sizeof(value_v6_value);
 

tests/bluetooth/tester/src/gatt.c

@@ -781,6 +781,7 @@ static uint8_t alloc_value(struct bt_gatt_attr *attr, struct set_value *data)
 			indicate_params.data = value->data;
 			indicate_params.len = value->len;
 			indicate_params.func = indicate_cb;
+			indicate_params.destroy = NULL;
 
 			bt_gatt_indicate(NULL, &indicate_params);
 		}