extmod/modbluetooth: Add gap_unpair command.

pi-anl · pi-anl · commit d47ac803d9d1 · 2025-05-21T13:56:56.000+10:00
This function deletes the pairing details from the DB on both the application and the radio, so can be used to free up IRK slots on the radio.
diff --git a/docs/library/bluetooth.rst b/docs/library/bluetooth.rst
@@ -733,6 +733,11 @@ Pairing and bonding
 
     On successful pairing, the ``_IRQ_ENCRYPTION_UPDATE`` event will be raised.
 
+.. method:: BLE.gap_unpair(key, /)
+
+    Removes pairing details from the bond database, where ``key`` is the entry key 
+    as provided in _IRQ_GET_SECRET/_IRQ_SET_SECRET events.
+
 .. method:: BLE.gap_passkey(conn_handle, action, passkey, /)
 
     Respond to a ``_IRQ_PASSKEY_ACTION`` event for the specified *conn_handle*
diff --git a/extmod/btstack/modbluetooth_btstack.c b/extmod/btstack/modbluetooth_btstack.c
@@ -1262,6 +1262,27 @@ int mp_bluetooth_gap_pair(uint16_t conn_handle) {
     return 0;
 }
 
+int mp_bluetooth_gap_unpair(uint8_t *key, size_t key_len) {
+    DEBUG_printf("mp_bluetooth_gap_unpair\n");
+    if (BD_ADDR_LEN != key_len) {
+        mp_raise_ValueError(MP_ERROR_TEXT("Incorrect key length"));
+    }
+
+    int addr_type;
+    bd_addr_t addr;
+    sm_key_t irk;
+    for (int i = 0; i < MAX_NR_LE_DEVICE_DB_ENTRIES; i++) {
+        le_device_db_info(i, &addr_type, addr, irk);
+        if (addr_type != BD_ADDR_TYPE_UNKNOWN) {
+            if (0 == memcmp(key, addr, BD_ADDR_LEN)) {
+                le_device_db_remove(i);
+                return 0;
+            }
+        }
+    }
+    return MP_ENOENT;
+}
+
 int mp_bluetooth_gap_passkey(uint16_t conn_handle, uint8_t action, mp_int_t passkey) {
     DEBUG_printf("mp_bluetooth_gap_passkey: conn_handle=%d action=%d passkey=%d\n", conn_handle, action, (int)passkey);
     return MP_EOPNOTSUPP;
diff --git a/extmod/modbluetooth.c b/extmod/modbluetooth.c
@@ -716,6 +716,21 @@ static mp_obj_t bluetooth_ble_gap_pair(mp_obj_t self_in, mp_obj_t conn_handle_in
 }
 static MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gap_pair_obj, bluetooth_ble_gap_pair);
 
+static mp_obj_t bluetooth_ble_gap_unpair(mp_obj_t self_in, mp_obj_t key_buff) {
+    (void)self_in;
+
+    uint8_t *key = NULL;
+    size_t key_len = 0;
+
+    mp_buffer_info_t key_bufinfo = {0};
+    mp_get_buffer_raise(key_buff, &key_bufinfo, MP_BUFFER_READ);
+    key = key_bufinfo.buf;
+    key_len = key_bufinfo.len;
+
+    return bluetooth_handle_errno(mp_bluetooth_gap_unpair(key, key_len));
+}
+static MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gap_unpair_obj, bluetooth_ble_gap_unpair);
+
 static mp_obj_t bluetooth_ble_gap_passkey(size_t n_args, const mp_obj_t *args) {
     uint16_t conn_handle = mp_obj_get_int(args[1]);
     uint8_t action = mp_obj_get_int(args[2]);
@@ -944,6 +959,7 @@ static const mp_rom_map_elem_t bluetooth_ble_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_gap_disconnect), MP_ROM_PTR(&bluetooth_ble_gap_disconnect_obj) },
     #if MICROPY_PY_BLUETOOTH_ENABLE_PAIRING_BONDING
     { MP_ROM_QSTR(MP_QSTR_gap_pair), MP_ROM_PTR(&bluetooth_ble_gap_pair_obj) },
+    { MP_ROM_QSTR(MP_QSTR_gap_unpair), MP_ROM_PTR(&bluetooth_ble_gap_unpair_obj) },
     { MP_ROM_QSTR(MP_QSTR_gap_passkey), MP_ROM_PTR(&bluetooth_ble_gap_passkey_obj) },
     #endif
     // GATT Server
diff --git a/extmod/modbluetooth.h b/extmod/modbluetooth.h
@@ -358,6 +358,9 @@ int mp_bluetooth_set_preferred_mtu(uint16_t mtu);
 // Initiate pairing on the specified connection.
 int mp_bluetooth_gap_pair(uint16_t conn_handle);
 
+// Remove a specific pairing key from the radio.
+int mp_bluetooth_gap_unpair(uint8_t *key, size_t key_len);
+
 // Respond to a pairing request.
 int mp_bluetooth_gap_passkey(uint16_t conn_handle, uint8_t action, mp_int_t passkey);
 #endif // MICROPY_PY_BLUETOOTH_ENABLE_PAIRING_BONDING
diff --git a/extmod/nimble/modbluetooth_nimble.c b/extmod/nimble/modbluetooth_nimble.c
@@ -1100,6 +1100,15 @@ int mp_bluetooth_gap_pair(uint16_t conn_handle) {
     return ble_hs_err_to_errno(ble_gap_security_initiate(conn_handle));
 }
 
+int mp_bluetooth_gap_unpair(uint8_t *key, size_t key_len) {
+    if (sizeof(ble_addr_t) != key_len) {
+        mp_raise_ValueError(MP_ERROR_TEXT("Incorrect key length"));
+    }
+
+    DEBUG_printf("mp_bluetooth_gap_unpair: specific\n");
+    return ble_hs_err_to_errno(ble_gap_unpair((ble_addr_t *)key));
+}
+
 int mp_bluetooth_gap_passkey(uint16_t conn_handle, uint8_t action, mp_int_t passkey) {
     struct ble_sm_io io = {0};
 
