| .. _bt_l2cap: |
| |
| Logical Link Control and Adaptation Protocol (L2CAP) |
| #################################################### |
| |
| L2CAP layer enables connection-oriented channels which can be enable with the |
| configuration option: :kconfig:option:`CONFIG_BT_L2CAP_DYNAMIC_CHANNEL`. This channels |
| support segmentation and reassembly transparently, they also support credit |
| based flow control making it suitable for data streams. |
| |
| Channels instances are represented by the :c:struct:`bt_l2cap_chan` struct which |
| contains the callbacks in the :c:struct:`bt_l2cap_chan_ops` struct to inform |
| when the channel has been connected, disconnected or when the encryption has |
| changed. |
| In addition to that it also contains the ``recv`` callback which is called |
| whenever an incoming data has been received. Data received this way can be |
| marked as processed by returning 0 or using |
| :c:func:`bt_l2cap_chan_recv_complete` API if processing is asynchronous. |
| |
| .. note:: |
| The ``recv`` callback is called directly from RX Thread thus it is not |
| recommended to block for long periods of time. |
| |
| For sending data the :c:func:`bt_l2cap_chan_send` API can be used noting that |
| it may block if no credits are available, and resuming as soon as more credits |
| are available. |
| |
| Servers can be registered using :c:func:`bt_l2cap_server_register` API passing |
| the :c:struct:`bt_l2cap_server` struct which informs what ``psm`` it should |
| listen to, the required security level ``sec_level``, and the callback |
| ``accept`` which is called to authorize incoming connection requests and |
| allocate channel instances. |
| |
| Client channels can be initiated with use of :c:func:`bt_l2cap_chan_connect` |
| API and can be disconnected with the :c:func:`bt_l2cap_chan_disconnect` API. |
| Note that the later can also disconnect channel instances created by servers. |
| |
| API Reference |
| ************* |
| |
| .. doxygengroup:: bt_l2cap |
