_bleio: support anonymous advertising

Add a new parameter to the `start_advertising()` function to enable
anonymous advertising.  This forces a call to `sd_ble_gap_privacy_set()`
with `privacy_mode` set to `BLE_GAP_PRIVACY_MODE_DEVICE_PRIVACY` and
`private_addr_type` set to
`BLE_GAP_ADDR_TYPE_RANDOM_PRIVATE_RESOLVABLE`.

With this, addresses will cycle at a predefined rate (currently once
every 15 minutes).

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

4 files changed, 33 insertions, 9 deletions

diff --git a/ports/nrf/common-hal/_bleio/Adapter.c b/ports/nrf/common-hal/_bleio/Adapter.c
index 36c79e88e..a1a2f6c3e 100644
--- a/ports/nrf/common-hal/_bleio/Adapter.c
+++ b/ports/nrf/common-hal/_bleio/Adapter.c
@@ -594,7 +594,7 @@ 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, float interval, uint8_t *advertising_data, uint16_t advertising_data_len, uint8_t *scan_response_data, uint16_t scan_response_data_len) {
+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) {
     if (self->current_advertising_data != NULL && self->current_advertising_data == self->advertising_data) {
         return NRF_ERROR_BUSY;
     }
@@ -605,7 +605,7 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
         common_hal_bleio_adapter_stop_advertising(self);
     }
 
-
+    uint32_t err_code;
     bool extended = advertising_data_len > BLE_GAP_ADV_SET_DATA_SIZE_MAX ||
                     scan_response_data_len > BLE_GAP_ADV_SET_DATA_SIZE_MAX;
 
@@ -626,7 +626,27 @@ uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self,
         adv_type = BLE_GAP_ADV_TYPE_NONCONNECTABLE_NONSCANNABLE_UNDIRECTED;
     }
 
-    uint32_t err_code;
+    if (anonymous) {
+        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,
+            .p_device_irk = NULL,
+        };
+        err_code = sd_ble_gap_privacy_set(&privacy);
+    } else {
+        ble_gap_privacy_params_t privacy = {
+            .privacy_mode = BLE_GAP_PRIVACY_MODE_OFF,
+            .private_addr_type = BLE_GAP_ADDR_TYPE_PUBLIC,
+            .private_addr_cycle_s = 0,
+            .p_device_irk = NULL,
+        };
+        err_code = sd_ble_gap_privacy_set(&privacy);
+    }
+    if (err_code != NRF_SUCCESS) {
+        return err_code;
+    }
+
     ble_gap_adv_params_t adv_params = {
         .interval = SEC_TO_UNITS(interval, UNIT_0_625_MS),
         .properties.type = adv_type,
@@ -657,7 +677,7 @@ 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, 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, 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."));
     }
@@ -681,7 +701,7 @@ 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, interval,
+    check_nrf_error(_common_hal_bleio_adapter_start_advertising(self, connectable, anonymous, interval,
                                                                 self->advertising_data,
                                                                 advertising_data_bufinfo->len,
                                                                 self->scan_response_data,
diff --git a/shared-bindings/_bleio/Adapter.c b/shared-bindings/_bleio/Adapter.c
index 4816294f7..e602e2ea1 100644
--- a/shared-bindings/_bleio/Adapter.c
+++ b/shared-bindings/_bleio/Adapter.c
@@ -145,17 +145,19 @@ const mp_obj_property_t bleio_adapter_name_obj = {
 //|         :param buf data: advertising data packet bytes
 //|         :param buf scan_response: scan response data packet bytes. ``None`` if no scan response is needed.
 //|         :param bool connectable:  If `True` then other devices are allowed to connect to this peripheral.
+//|         :param bool anonymous:  If `True` then this device's MAC address is randomized regularly.
 //|         :param float interval:  advertising interval, in seconds"""
 //|         ...
 //|
 STATIC mp_obj_t bleio_adapter_start_advertising(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     bleio_adapter_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
 
-    enum { ARG_data, ARG_scan_response, ARG_connectable, ARG_interval };
+    enum { ARG_data, ARG_scan_response, ARG_connectable, ARG_anonymous, ARG_interval };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_data, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_scan_response, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
         { MP_QSTR_connectable, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = true} },
+        { MP_QSTR_anonymous, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
         { MP_QSTR_interval, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
     };
 
@@ -182,11 +184,12 @@ STATIC mp_obj_t bleio_adapter_start_advertising(mp_uint_t n_args, const mp_obj_t
     }
 
     bool connectable = args[ARG_connectable].u_bool;
+    bool anonymous = args[ARG_anonymous].u_bool;
     if (data_bufinfo.len > 31 && connectable && scan_response_bufinfo.len > 0) {
         mp_raise_bleio_BluetoothError(translate("Cannot have scan responses for extended, connectable advertisements."));
     }
 
-    common_hal_bleio_adapter_start_advertising(self, connectable, interval,
+    common_hal_bleio_adapter_start_advertising(self, connectable, anonymous, interval,
                                                &data_bufinfo, &scan_response_bufinfo);
 
     return mp_const_none;
diff --git a/shared-bindings/_bleio/Adapter.h b/shared-bindings/_bleio/Adapter.h
index 9b20a461a..30d876340 100644
--- a/shared-bindings/_bleio/Adapter.h
+++ b/shared-bindings/_bleio/Adapter.h
@@ -45,9 +45,9 @@ extern bleio_address_obj_t *common_hal_bleio_adapter_get_address(bleio_adapter_o
 extern mp_obj_str_t* common_hal_bleio_adapter_get_name(bleio_adapter_obj_t *self);
 extern void common_hal_bleio_adapter_set_name(bleio_adapter_obj_t *self, const char* name);
 
-extern uint32_t _common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, float interval, uint8_t *advertising_data, uint16_t advertising_data_len, uint8_t *scan_response_data, uint16_t scan_response_data_len);
+extern 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);
 
-extern void common_hal_bleio_adapter_start_advertising(bleio_adapter_obj_t *self, bool connectable, mp_float_t interval, mp_buffer_info_t *advertising_data_bufinfo, mp_buffer_info_t *scan_response_data_bufinfo);
+extern 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);
 extern void common_hal_bleio_adapter_stop_advertising(bleio_adapter_obj_t *self);
 
 extern mp_obj_t common_hal_bleio_adapter_start_scan(bleio_adapter_obj_t *self, uint8_t* prefixes, size_t prefix_length, bool extended, mp_int_t buffer_size, mp_float_t timeout, mp_float_t interval, mp_float_t window, mp_int_t minimum_rssi, bool active);
diff --git a/supervisor/shared/bluetooth.c b/supervisor/shared/bluetooth.c
index b463160cf..6b1c03fc0 100644
--- a/supervisor/shared/bluetooth.c
+++ b/supervisor/shared/bluetooth.c
@@ -74,6 +74,7 @@ void supervisor_bluetooth_start_advertising(void) {
     // TODO: switch to Adafruit short UUID for the advertisement and add manufacturing data to distinguish ourselves from arduino.
     _common_hal_bleio_adapter_start_advertising(&common_hal_bleio_adapter_obj,
                                                    true,
+                                                   false,
                                                    1.0,
                                                    circuitpython_advertising_data,
                                                    sizeof(circuitpython_advertising_data),