L2CAP Update

doc/connectivity/bluetooth/api/l2cap.rst

@@ -3,11 +3,45 @@
 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
+L2CAP layer enables connection-oriented channels which can be enabled with the
+configuration option: :kconfig:option:`CONFIG_BT_L2CAP_DYNAMIC_CHANNEL`. These channels
 support segmentation and reassembly transparently, they also support credit
 based flow control making it suitable for data streams.
 
+The user can also define fixed channels using the :c:macro:`BT_L2CAP_FIXED_CHANNEL_DEFINE`
+macro. Fixed channels are initialized upon connection, and do not support segmentation. An example
+of how to define a fixed channel is shown below.
+
+.. code-block:: c
+
+   static struct bt_l2cap_chan fixed_chan[CONFIG_BT_MAX_CONN];
+
+   /* Callbacks are assumed to be defined prior. */
+   static struct bt_l2cap_chan_ops ops = {
+       .recv = recv_cb,
+       .sent = sent_cb,
+       .connected = connected_cb,
+       .disconnected = disconnected_cb,
+   };
+
+   static int l2cap_fixed_accept(struct bt_conn *conn, struct bt_l2cap_chan **chan)
+   {
+       uint8_t conn_index = bt_conn_index(conn);
+
+       *chan = &fixed_chan[conn_index];
+
+       **chan = (struct bt_l2cap_chan){
+           .ops = &ops,
+       };
+
+       return 0;
+   }
+
+   BT_L2CAP_FIXED_CHANNEL_DEFINE(fixed_channel) = {
+       .cid = 0x0010,
+       .accept = l2cap_fixed_accept,
+   };
+
 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

include/zephyr/bluetooth/classic/l2cap_br.h

@@ -0,0 +1,258 @@
+/** @file
+ *  @brief Bluetooth L2CAP BR/EDR handling
+ */
+
+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_BR_H_
+#define ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_BR_H_
+
+/**
+ * @brief L2CAP
+ * @defgroup bt_l2cap L2CAP
+ * @ingroup bluetooth
+ * @{
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <zephyr/bluetooth/buf.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/kernel.h>
+#include <zephyr/net_buf.h>
+#include <zephyr/sys/atomic.h>
+#include <zephyr/sys/slist.h>
+#include <zephyr/sys/util.h>
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief ECHO request/response callback structure.
+ *
+ * This structure is used for tracking the ECHO request/response signaling packets of L2CAP BR.
+ * It is registered with the help of the bt_l2cap_br_echo_cb_register() API.
+ * It's permissible to register multiple instances of this @ref bt_l2cap_br_echo_cb type, in case
+ * different modules of an application are interested in tracking the ECHO request/response
+ * signaling packets. If a callback is not of interest for an instance, it may be set to NULL and
+ * will as a consequence not be used for that instance.
+ */
+struct bt_l2cap_br_echo_cb {
+	/**
+	 * @brief A ECHO request has been received.
+	 *
+	 * This callback notifies the application of a ECHO request has been received.
+	 * The ECHO response should be performed by calling the bt_l2cap_br_echo_rsp() API.
+	 *
+	 * @param conn The ACL connection object.
+	 * @param identifier The identifier of the ECHO request.
+	 * @param buf Received ECHO data.
+	 */
+	void (*req)(struct bt_conn *conn, uint8_t identifier, struct net_buf *buf);
+
+	/**
+	 * @brief A ECHO response has been received.
+	 *
+	 * This callback notifies the application of a ECHO response has been received.
+	 *
+	 * @param conn The ACL connection object.
+	 * @param buf Received ECHO data.
+	 */
+	void (*rsp)(struct bt_conn *conn, struct net_buf *buf);
+
+	/** @internal Internally used field for list handling */
+	sys_snode_t _node;
+};
+
+/**
+ * @brief Register ECHO callbacks.
+ *
+ * Register callbacks to monitor the packets of L2CAP BR echo request/response.
+ *
+ * @param cb Callback struct. Must point to memory that remains valid.
+ *
+ * @retval 0 Success.
+ * @retval -EEXIST if @p cb was already registered.
+ */
+int bt_l2cap_br_echo_cb_register(struct bt_l2cap_br_echo_cb *cb);
+
+/**
+ * @brief Unregister ECHO callbacks.
+ *
+ * Unregister callbacks that are used to monitor the packets of L2CAP BR echo request/response.
+ *
+ * @param cb Callback struct point to memory that remains valid.
+ *
+ * @retval 0 Success.
+ * @retval -EINVAL If @p cb is NULL.
+ * @retval -ENOENT if @p cb was not registered.
+ */
+int bt_l2cap_br_echo_cb_unregister(struct bt_l2cap_br_echo_cb *cb);
+
+/**
+ *  @brief Headroom needed for outgoing L2CAP ECHO REQ PDUs.
+ */
+#define BT_L2CAP_BR_ECHO_REQ_RESERVE BT_L2CAP_BUF_SIZE(4)
+
+/**
+ *  @brief Headroom needed for outgoing L2CAP ECHO RSP PDUs.
+ */
+#define BT_L2CAP_BR_ECHO_RSP_RESERVE BT_L2CAP_BUF_SIZE(4)
+
+/**
+ * @brief Send ECHO data through ECHO request
+ *
+ * Send ECHO data through ECHO request. The application is required to have reserved
+ * @ref BT_L2CAP_BR_ECHO_REQ_RESERVE bytes in the buffer before sending.
+ *
+ * @param conn The ACL connection object.
+ * @param buf Sending ECHO data.
+ *
+ * @return 0 in case of success or negative value in case of error.
+ */
+int bt_l2cap_br_echo_req(struct bt_conn *conn, struct net_buf *buf);
+
+/**
+ * @brief Send ECHO data through ECHO response
+ *
+ * Send ECHO data through ECHO response. The application is required to have reserved
+ * @ref BT_L2CAP_BR_ECHO_RSP_RESERVE bytes in the buffer before sending.
+ *
+ * @param conn The ACL connection object.
+ * @param identifier The identifier of the ECHO request.
+ * @param buf Sending ECHO data.
+ *
+ * @return 0 in case of success or negative value in case of error.
+ */
+int bt_l2cap_br_echo_rsp(struct bt_conn *conn, uint8_t identifier, struct net_buf *buf);
+
+/**
+ * @brief Connectionless data channel callback structure.
+ *
+ * This structure is used for tracking the connectionless data channel frames.
+ * It is registered with the help of the bt_l2cap_br_connless_register() API.
+ * It's permissible to register multiple instances of this @ref bt_l2cap_br_connless_cb type,
+ * in case different modules of an application are interested in tracking the connectionless
+ * data channel frames.
+ */
+struct bt_l2cap_br_connless_cb {
+	/** @brief Register PSM.
+	 *
+	 *  For BR, possible values:
+	 *
+	 *  The PSM field is at least two octets in length. All PSM values shall have the least
+	 *  significant bit of the most significant octet equal to 0 and the least significant bit
+	 *  of all other octets equal to 1.
+	 *
+	 *  0               Any connectionless data channel frame will be notified.
+	 *
+	 *  0x0001-0x0eff   Standard, Bluetooth SIG-assigned fixed values.
+	 *
+	 *  > 0x1000        Dynamically allocated. May be pre-set by the
+	 *                  application before server registration (not
+	 *                  recommended however), or auto-allocated by the
+	 *                  stack if the app gave 0 as the value.
+	 */
+	uint16_t psm;
+
+	/** Required minimum security level */
+	bt_security_t sec_level;
+
+	/**
+	 * @brief A connectionless channel data has been received.
+	 *
+	 * This callback notifies the application of a connectionless channel data has been
+	 * received.
+	 *
+	 * @param conn The ACL connection object.
+	 * @param psm Protocol/Service Multiplexer.
+	 * @param buf Received connectionless channel data.
+	 */
+	void (*recv)(struct bt_conn *conn, uint16_t psm, struct net_buf *buf);
+
+	/** @internal Internally used field for list handling */
+	sys_snode_t _node;
+};
+
+/**
+ * @brief Register connectionless data channel callbacks.
+ *
+ * Register callbacks to monitor and receive connectionless data channel frames.
+ * This allows the application to receive data sent to a specific PSM without
+ * establishing a connection.
+ *
+ * @param cb Callback struct. Must point to memory that remains valid.
+ *           The PSM field must be set to the desired Protocol/Service Multiplexer
+ *           value, or 0 to receive all connectionless data frames.
+ *
+ * @retval 0 Success.
+ * @retval -EINVAL If @p cb is NULL, has invalid PSM value, has invalid `recv` callback,
+ *                 or has invalid security level.
+ * @retval -EEXIST If a callback with the same PSM was already registered.
+ */
+int bt_l2cap_br_connless_register(struct bt_l2cap_br_connless_cb *cb);
+
+/**
+ * @brief Unregister connectionless data channel callbacks.
+ *
+ * Unregister callbacks that are used to monitor and receive connectionless data channel frames.
+ *
+ * @param cb Registered cb.
+ *
+ * @retval 0 Success.
+ * @retval -EINVAL If @p cb is NULL.
+ * @retval -ENOENT if @p cb was not registered.
+ */
+int bt_l2cap_br_connless_unregister(struct bt_l2cap_br_connless_cb *cb);
+
+/**
+ *  @brief L2CAP connectionless SDU header size.
+ */
+#define BT_L2CAP_CONNLESS_SDU_HDR_SIZE 2
+
+/**
+ *  @brief Headroom needed for outgoing L2CAP PDU format within a connectionless data channel.
+ */
+#define BT_L2CAP_CONNLESS_RESERVE BT_L2CAP_BUF_SIZE(BT_L2CAP_CONNLESS_SDU_HDR_SIZE)
+
+/**
+ * @brief Send data over connectionless data channel
+ *
+ * Send data over a connectionless data channel. This function allows sending data to
+ * a specific PSM without establishing the L2CAP channel connection.
+ *
+ * The application is required to have reserved @ref BT_L2CAP_CONNLESS_RESERVE bytes
+ * in the buffer before sending.
+ *
+ * @param conn Connection object.
+ * @param psm Protocol/Service Multiplexer identifying the destination service.
+ * @param buf Buffer containing the data to be sent. The application is required to
+ *            have reserved enough headroom in the buffer for the L2CAP header.
+ *
+ * @retval 0 Success.
+ * @retval -EINVAL If @p conn or @p buf is NULL, @p psm is invalid, the reference counter of @p buf
+ *                 != 1, the head room of @p buf is less than @ref BT_L2CAP_CONNLESS_RESERVE, or
+ *                 the `buf->user_data_size` is less than the size of `struct closure`.
+ * @return -ENOTSUP If the connectionless reception feature is unsupported by remote.
+ * @return -ENOTCONN If the L2CAP channel with connectionless channel is not found.
+ * @return -EMSGSIZE If the data size exceeds the peer's connectionless channel MTU.
+ * @retval -ESHUTDOWN If the L2CAP channel with connectionless channel is NULL in low level.
+ */
+int bt_l2cap_br_connless_send(struct bt_conn *conn, uint16_t psm, struct net_buf *buf);
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_BR_H_ */