bleio: adapter: add advertising timeout and status

Add a field to allow specifying a timeout when initiating advertising.
As part of this, add a new property to determine if the device is still
advertising.

Additionally, have the `anonymous` property require a timeout, and set
the timeout to the maximum possible value if no timeout is specified.

Signed-off-by: Sean Cross <sean@xobs.io>

1 files changed, 56 insertions, 5 deletions

diff --git a/ports/nrf/common-hal/_bleio/Adapter.c b/ports/nrf/common-hal/_bleio/Adapter.c
index a1a2f6c3e..83cd3bc1b 100644
--- a/ports/nrf/common-hal/_bleio/Adapter.c
+++ b/ports/nrf/common-hal/_bleio/Adapter.c
@@ -26,6 +26,7 @@
  * THE SOFTWARE.
  */
 
+#include <math.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -594,7 +595,26 @@ STATIC void check_data_fit(size_t data_len, bool connectable) {
     }
 }
 
-uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, bool anonymous, float interval, uint8_t *advertising_data, uint16_t advertising_data_len, uint8_t *scan_response_data, uint16_t scan_response_data_len) {
+STATIC bool advertising_on_ble_evt(ble_evt_t *ble_evt, void *self_in) {
+    bleio_adapter_obj_t *self = (bleio_adapter_obj_t*)self_in;
+
+    switch (ble_evt->header.evt_id) {
+        case BLE_GAP_EVT_ADV_SET_TERMINATED:
+            mp_printf(&mp_plat_print, "Advertising set terminated - %d advertising events were completed - reason: %d\n", ble_evt->evt.gap_evt.params.adv_set_terminated.num_completed_adv_events, ble_evt->evt.gap_evt.params.adv_set_terminated.reason);
+            common_hal_bleio_adapter_stop_advertising(self);
+            ble_drv_remove_event_handler(advertising_on_ble_evt, self_in);
+            break;
+
+        default:
+            // For debugging.
+            mp_printf(&mp_plat_print, "Unhandled Advertising etvent: 0x%04x\n", ble_evt->header.evt_id);
+            return false;
+            break;
+    }
+    return true;
+}
+
+uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, bool anonymous, uint32_t timeout, float interval, uint8_t *advertising_data, uint16_t advertising_data_len, uint8_t *scan_response_data, uint16_t scan_response_data_len) {
     if (self->current_advertising_data != NULL && self->current_advertising_data == self->advertising_data) {
         return NRF_ERROR_BUSY;
     }
@@ -630,7 +650,11 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
         ble_gap_privacy_params_t privacy = {
             .privacy_mode = BLE_GAP_PRIVACY_MODE_DEVICE_PRIVACY,
             .private_addr_type = BLE_GAP_ADDR_TYPE_RANDOM_PRIVATE_RESOLVABLE,
-            .private_addr_cycle_s = 0,
+            // Rotate the keys one second after we're scheduled to stop
+            // advertising. This prevents a potential race condition where we
+            // fire off a beacon with the same advertising data but a new MAC
+            // address just as we tear down the connection.
+            .private_addr_cycle_s = timeout + 1,
             .p_device_irk = NULL,
         };
         err_code = sd_ble_gap_privacy_set(&privacy);
@@ -650,7 +674,7 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
     ble_gap_adv_params_t adv_params = {
         .interval = SEC_TO_UNITS(interval, UNIT_0_625_MS),
         .properties.type = adv_type,
-        .duration = BLE_GAP_ADV_TIMEOUT_GENERAL_UNLIMITED,
+        .duration = SEC_TO_UNITS(timeout, UNIT_10_MS),
         .filter_policy = BLE_GAP_ADV_FP_ANY,
         .primary_phy = BLE_GAP_PHY_1MBPS,
     };
@@ -667,6 +691,8 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
         return err_code;
     }
 
+    ble_drv_add_event_handler(advertising_on_ble_evt, self);
+
     vm_used_ble = true;
     err_code = sd_ble_gap_adv_start(adv_handle, BLE_CONN_CFG_TAG_CUSTOM);
     if (err_code != NRF_SUCCESS) {
@@ -677,7 +703,7 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
 }
 
 
-void common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, bool anonymous, mp_float_t interval, mp_buffer_info_t *advertising_data_bufinfo, mp_buffer_info_t *scan_response_data_bufinfo) {
+void common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, bool anonymous, uint32_t timeout, mp_float_t interval, mp_buffer_info_t *advertising_data_bufinfo, mp_buffer_info_t *scan_response_data_bufinfo) {
     if (self->current_advertising_data != NULL && self->current_advertising_data == self->advertising_data) {
         mp_raise_bleio_BluetoothError(translate("Already advertising."));
     }
@@ -689,6 +715,27 @@ void common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool
     if (advertising_data_bufinfo->len > 31 && scan_response_data_bufinfo->len > 0) {
         mp_raise_bleio_BluetoothError(translate("Extended advertisements with scan response not supported."));
     }
+
+    // Anonymous mode requires a timeout so that we don't continue to broadcast
+    // the same data while cycling the MAC address -- otherwise, what's the
+    // point of randomizing the MAC address?
+    if (!timeout) {
+        if (anonymous) {
+            // The Nordic macro is in units of 10ms. Convert to seconds.
+            uint32_t adv_timeout_max_secs = BLE_GAP_ADV_TIMEOUT_LIMITED_MAX / 100;
+            uint32_t rotate_timeout_max_secs = BLE_GAP_DEFAULT_PRIVATE_ADDR_CYCLE_INTERVAL_S;
+            timeout = MIN(adv_timeout_max_secs, rotate_timeout_max_secs);
+        }
+        else {
+            timeout = BLE_GAP_ADV_TIMEOUT_GENERAL_UNLIMITED;
+        }
+    } else {
+        if (SEC_TO_UNITS(timeout, UNIT_10_MS) > BLE_GAP_ADV_TIMEOUT_LIMITED_MAX) {
+            mp_raise_bleio_BluetoothError(translate("Timeout is too long: Maximum timeout length is %d seconds"),
+                                        BLE_GAP_ADV_TIMEOUT_LIMITED_MAX / 100);
+        }
+    }
+
     // The advertising data buffers must not move, because the SoftDevice depends on them.
     // So make them long-lived and reuse them onwards.
     if (self->advertising_data == NULL) {
@@ -701,7 +748,7 @@ void common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool
     memcpy(self->advertising_data, advertising_data_bufinfo->buf, advertising_data_bufinfo->len);
     memcpy(self->scan_response_data, scan_response_data_bufinfo->buf, scan_response_data_bufinfo->len);
 
-    check_nrf_error(_common_hal_bleio_adapter_start_advertising(self, connectable, anonymous, interval,
+    check_nrf_error(_common_hal_bleio_adapter_start_advertising(self, connectable, anonymous, timeout, interval,
                                                                 self->advertising_data,
                                                                 advertising_data_bufinfo->len,
                                                                 self->scan_response_data,
@@ -721,6 +768,10 @@ void common_hal_bleio_adapter_stop_advertising(bleio_adapter_obj_t *self) {
     }
 }
 
+bool common_hal_bleio_adapter_get_advertising(bleio_adapter_obj_t *self) {
+    return self->current_advertising_data != NULL;
+}
+
 bool common_hal_bleio_adapter_get_connected(bleio_adapter_obj_t *self) {
     for (size_t i = 0; i < BLEIO_TOTAL_CONNECTION_COUNT; i++) {
         bleio_connection_internal_t *connection = &bleio_connections[i];