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46 lines
3.4 KiB
46 lines
3.4 KiB
4 years ago
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NimBLE Host Identity Reference
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------------------------------
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Introduction
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~~~~~~~~~~~~
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The identity API provides facilities for querying and configuring your device's addresses. BLE's addressing scheme is
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quite involved; the summary that follows is only a brief introduction.
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BLE defines four address types:
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+---------------------------------+---------------------------------------------------------------------------------------------------+-------------+----------------------------------------------+
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| Type | Description | Identity? | Configured with |
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+=================================+===================================================================================================+=============+==============================================+
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| Public | Address assigned by manufacturer; the three most significant bytes form the manufacturer's OUI. | Yes | N/A; read from controller at startup. |
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+---------------------------------+---------------------------------------------------------------------------------------------------+-------------+----------------------------------------------+
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| Static random | Randomly generated address. | Yes | *ble_hs_id_set_rnd()* |
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+---------------------------------+---------------------------------------------------------------------------------------------------+-------------+----------------------------------------------+
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| Resolvable private (RPA) | Address randomly generated from an identity address and an identity resolving key (IRK). | No | N/A; generated by controller periodically. |
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+---------------------------------+---------------------------------------------------------------------------------------------------+-------------+----------------------------------------------+
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| Non-resolvable private (NRPA) | Randomly generated address. | No | *ble_hs_id_set_rnd()* |
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+---------------------------------+---------------------------------------------------------------------------------------------------+-------------+----------------------------------------------+
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Identity Addresses
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^^^^^^^^^^^^^^^^^^
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The third column in the above table indicates the *identity* property of each address type. An identity address never
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changes, and a device can be identified by one of its unique identity addresses.
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Non-identity addresses are used by devices supporting BLE privacy. A device using the privacy feature frequently changes
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its own address to a newly-generated non-identity address. By cycling its address, the device makes it impossible for
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eavesdroppers to track its location.
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A device can have up to two identity addresses at once: one public and one static random. As indicated in the above table,
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the public identity address cannot be configured; the static random identity address can be set by calling *ble_hs_id_set_rnd()*.
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The address type is selected on a per-GAP-procedure basis. Each time you initiate a GAP procedure, you indicate which
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address type the device should use for the duration of the procedure.
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Header
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~~~~~~
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.. code-block:: cpp
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#include "host/ble_hs.h"
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