bluetooth: adv: add rpa timeout callback to extended advertising api

Added a new callback to the Bluetooth Extended Advertising callback
structure. It notifies the application that the RPA validity of the
advertising set has timed out. The user can use this callback to
synchronize the advertising payload update with the RPA rotation.

Signed-off-by: Kamil Piszczek <[email protected]>

Author: kapi-no

include/zephyr/bluetooth/bluetooth.h

@@ -114,6 +114,22 @@ struct bt_le_ext_adv_cb {
 	 */
 	void (*scanned)(struct bt_le_ext_adv *adv,
 			struct bt_le_ext_adv_scanned_info *info);
+
+#if defined(CONFIG_BT_PRIVACY)
+	/**
+	 * @brief The RPA validity of the advertising set has expired.
+	 *
+	 * This callback notifies the application that the RPA validity of
+	 * the advertising set has expired. The user can use this callback
+	 * to synchronize the advertising payload update with the RPA rotation.
+	 *
+	 * @param adv  The advertising set object.
+	 *
+	 * @return true to rotate the current RPA, or false to use it for the
+	 *         next rotation period.
+	 */
+	bool (*rpa_expired)(struct bt_le_ext_adv *adv);
+#endif /* defined(CONFIG_BT_PRIVACY) */
 };
 
 /**

subsys/bluetooth/host/id.c

@@ -350,6 +350,7 @@ static void adv_disable_rpa(struct bt_le_ext_adv *adv, void *data)
 {
 	uint8_t adv_index = bt_le_ext_adv_get_index(adv);
 	bool *adv_disabled = data;
+	bool rpa_invalid = true;
 
 	adv_disabled[adv_index] = false;
 
@@ -366,7 +367,14 @@ static void adv_disable_rpa(struct bt_le_ext_adv *adv, void *data)
 		adv_disabled[adv_index] = true;
 	}
 
-	atomic_clear_bit(adv->flags, BT_ADV_RPA_VALID);
+	/* Notify the user about the RPA timeout and set the RPA validity. */
+	if (adv->cb && adv->cb->rpa_expired) {
+		rpa_invalid = adv->cb->rpa_expired(adv);
+	}
+
+	if (rpa_invalid) {
+		atomic_clear_bit(adv->flags, BT_ADV_RPA_VALID);
+	}
 }
 
 static void adv_enable_rpa(struct bt_le_ext_adv *adv, void *data)
@@ -394,6 +402,12 @@ static void adv_update_rpa_foreach(void)
 	bool adv_disabled[CONFIG_BT_EXT_ADV_MAX_ADV_SET];
 
 	bt_le_ext_adv_foreach(adv_disable_rpa, adv_disabled);
+
+	/* Submit the timeout in case all sets use the same
+	 * RPA for the next rotation period.
+	 */
+	le_rpa_timeout_submit();
+
 	bt_le_ext_adv_foreach(adv_enable_rpa, adv_disabled);
 #endif
 }