Commit 6f2b8f8a authored by Lyle Zhu's avatar Lyle Zhu Committed by Anas Nashif
Browse files

Bluetooth: Classic: L2CAP: implement ECHO REQ/RSP 



Handle the ECHO request/response of classic L2CAP signaling packets.

Add the functions `bt_l2cap_br_echo_cb_register()` and
`bt_l2cap_br_echo_cb_unregister()` to register/unregister the ECHO
callbacks to monitor the ECHO REQ and RSP.

Add the function `bt_l2cap_br_echo_req()` to send the ECHO REQ through
classic L2CAP signaling channel.

Add the function `bt_l2cap_br_echo_rsp()` to reply the ECHO REQ
through the classic L2CAP signaling channel.

Signed-off-by: default avatarLyle Zhu <lyle.zhu@nxp.com>
parent 02f2beab

include/zephyr/bluetooth/classic/l2cap_br.h

0 → 100644
+144 −0
Original line number Diff line number Diff line 
/** @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);



#ifdef __cplusplus

}

#endif



/**

 * @}

 */



#endif /* ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_BR_H_ */

subsys/bluetooth/host/classic/l2cap_br.c

+177 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <errno.h>

#include <zephyr/sys/atomic.h>

#include <zephyr/sys/byteorder.h>

#include <zephyr/sys/check.h>

#include <zephyr/sys/iterable_sections.h>

#include <zephyr/sys/util.h>

#include <zephyr/sys/crc.h>
@@ -18,6 +19,7 @@ 
#include <zephyr/bluetooth/hci.h>

#include <zephyr/bluetooth/bluetooth.h>

#include <zephyr/bluetooth/conn.h>

#include <zephyr/bluetooth/classic/l2cap_br.h>



#include "host/buf_view.h"

#include "host/hci_core.h"
@@ -75,6 +77,7 @@ LOG_MODULE_REGISTER(bt_l2cap_br, CONFIG_BT_L2CAP_LOG_LEVEL); 
#define L2CAP_BR_CFG_TIMEOUT     K_SECONDS(4)

#define L2CAP_BR_DISCONN_TIMEOUT K_SECONDS(1)

#define L2CAP_BR_CONN_TIMEOUT    K_SECONDS(40)

#define L2CAP_BR_ECHO_TIMEOUT    K_SECONDS(30)



#define L2CAP_FEAT_FC_MASK           BIT(0)

#define L2CAP_FEAT_RET_MASK          BIT(1)
@@ -228,6 +231,8 @@ struct bt_l2cap_br { 


static struct bt_l2cap_br bt_l2cap_br_pool[CONFIG_BT_MAX_CONN];



static sys_slist_t bt_l2cap_br_echo_cbs = SYS_SLIST_STATIC_INIT(&bt_l2cap_br_echo_cbs);



struct bt_l2cap_chan *bt_l2cap_br_lookup_rx_cid(struct bt_conn *conn,

						uint16_t cid)

{
@@ -343,6 +348,7 @@ static void l2cap_br_rtx_timeout(struct k_work *work) 
	if (chan->rx.cid == BT_L2CAP_CID_BR_SIG) {

		LOG_DBG("Skip BR/EDR signalling channel ");

		atomic_clear_bit(chan->flags, L2CAP_FLAG_SIG_INFO_PENDING);

		chan->ident = 0;

		return;

	}
@@ -4521,6 +4527,7 @@ static void l2cap_br_disconnected(struct bt_l2cap_chan *chan) 
		 * so this should always succeed.

		 */

		(void)k_work_cancel_delayable(&br_chan->rtx_work);

		br_chan->ident = 0;

	}

}
@@ -4820,6 +4827,40 @@ static void l2cap_br_reject_rsp(struct bt_l2cap_br *l2cap, uint8_t ident, struct 
	} while (chan != NULL);

}



static void l2cap_br_echo_req(struct bt_l2cap_br *l2cap, uint8_t ident, struct net_buf *buf)

{

	struct bt_conn *conn = l2cap->chan.chan.conn;

	struct bt_l2cap_br_echo_cb *callback;



	SYS_SLIST_FOR_EACH_CONTAINER(&bt_l2cap_br_echo_cbs, callback, _node) {

		if (callback->req) {

			callback->req(conn, ident, buf);

		}

	}

}



static void l2cap_br_echo_rsp(struct bt_l2cap_br *l2cap, uint8_t ident, struct net_buf *buf)

{

	struct bt_conn *conn = l2cap->chan.chan.conn;

	struct bt_l2cap_br_echo_cb *callback;



	if (ident != l2cap->chan.ident) {

		LOG_WRN("ident mismatch (%u != %u)!", l2cap->chan.ident, ident);

		goto failed;

	}



	SYS_SLIST_FOR_EACH_CONTAINER(&bt_l2cap_br_echo_cbs, callback, _node) {

		if (callback->rsp) {

			callback->rsp(conn, buf);

		}

	}



failed:

	l2cap->chan.ident = 0;

	/* Release RTX work since got the response */

	k_work_cancel_delayable(&l2cap->chan.rtx_work);

}



static void l2cap_br_sig_handle(struct bt_l2cap_br *l2cap, struct bt_l2cap_sig_hdr *hdr,

				struct net_buf *buf)

{
@@ -4858,6 +4899,12 @@ static void l2cap_br_sig_handle(struct bt_l2cap_br *l2cap, struct bt_l2cap_sig_h 
	case BT_L2CAP_CMD_REJECT:

		l2cap_br_reject_rsp(l2cap, hdr->ident, buf);

		break;

	case BT_L2CAP_ECHO_REQ:

		l2cap_br_echo_req(l2cap, hdr->ident, buf);

		break;

	case BT_L2CAP_ECHO_RSP:

		l2cap_br_echo_rsp(l2cap, hdr->ident, buf);

		break;

	default:

		LOG_WRN("Unknown/Unsupported L2CAP PDU code 0x%02x", hdr->code);

		l2cap_br_send_reject(l2cap->chan.chan.conn, hdr->ident, BT_L2CAP_REJ_NOT_UNDERSTOOD,
@@ -6003,3 +6050,133 @@ void bt_l2cap_br_init(void) 
		bt_avrcp_init();

	}

}



int bt_l2cap_br_echo_cb_register(struct bt_l2cap_br_echo_cb *cb)

{

	CHECKIF(cb == NULL) {

		return -EINVAL;

	}



	if (sys_slist_find(&bt_l2cap_br_echo_cbs, &cb->_node, NULL)) {

		return -EEXIST;

	}



	sys_slist_append(&bt_l2cap_br_echo_cbs, &cb->_node);



	return 0;

}



int bt_l2cap_br_echo_cb_unregister(struct bt_l2cap_br_echo_cb *cb)

{

	CHECKIF(cb == NULL) {

		return -EINVAL;

	}



	if (!sys_slist_find_and_remove(&bt_l2cap_br_echo_cbs, &cb->_node)) {

		return -ENOENT;

	}



	return 0;

}



int bt_l2cap_br_echo_req(struct bt_conn *conn, struct net_buf *buf)

{

	struct bt_l2cap_chan *chan;

	struct bt_l2cap_sig_hdr *hdr;

	int err;



	if ((conn == NULL) || (buf == NULL)) {

		return -EINVAL;

	}



	LOG_DBG("ACL conn %p buf %p len %u", conn, buf, buf->len);



	if (buf->ref != 1) {

		LOG_WRN("Expecting 1 ref, got %d", buf->ref);

		return -EINVAL;

	}



	if (buf->len >= (L2CAP_BR_MIN_MTU - sizeof(*hdr))) {

		LOG_ERR("attempt to send %u bytes on %u MTU chan", buf->len, L2CAP_BR_MIN_MTU);

		return -EMSGSIZE;

	}



	if (net_buf_headroom(buf) < BT_L2CAP_BR_ECHO_REQ_RESERVE) {

		/* Call `net_buf_reserve(buf, BT_L2CAP_BR_ECHO_REQ_RESERVE)`

		 * when allocating buffers intended for bt_l2cap_br_echo_req().

		 */

		LOG_ERR("Not enough headroom in buf %p", buf);

		return -EINVAL;

	}



	chan = bt_l2cap_br_lookup_rx_cid(conn, BT_L2CAP_CID_BR_SIG);

	if (chan == NULL) {

		LOG_ERR("Signaling Channel %u not found", BT_L2CAP_CID_BR_SIG);

		return -ENOTCONN;

	}



	if (BR_CHAN(chan)->ident) {

		LOG_ERR("Waiting for ECHO RSP");

		return -EBUSY;

	}



	hdr = net_buf_push(buf, sizeof(*hdr));



	hdr->code = BT_L2CAP_ECHO_REQ;

	hdr->ident = l2cap_br_get_ident();

	hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));



	/* Set the ident for the signaling request */

	BR_CHAN(chan)->ident = hdr->ident;



	err = bt_l2cap_br_send_cb(conn, BT_L2CAP_CID_BR_SIG, buf, NULL, NULL);

	if (err == 0) {

		k_work_reschedule(&BR_CHAN(chan)->rtx_work, L2CAP_BR_ECHO_TIMEOUT);

	}



	return err;

}



int bt_l2cap_br_echo_rsp(struct bt_conn *conn, uint8_t identifier, struct net_buf *buf)

{

	struct bt_l2cap_chan *chan;

	struct bt_l2cap_sig_hdr *hdr;



	if ((conn == NULL) || (buf == NULL) || (identifier == 0)) {

		return -EINVAL;

	}



	LOG_DBG("ACL conn %p buf %p len %u", conn, buf, buf->len);



	if (buf->ref != 1) {

		LOG_WRN("Expecting 1 ref, got %d", buf->ref);

		return -EINVAL;

	}



	if (buf->len >= (L2CAP_BR_MIN_MTU - sizeof(*hdr))) {

		LOG_ERR("attempt to send %u bytes on %u MTU chan", buf->len, L2CAP_BR_MIN_MTU);

		return -EMSGSIZE;

	}



	if (net_buf_headroom(buf) < BT_L2CAP_BR_ECHO_RSP_RESERVE) {

		/* Call `net_buf_reserve(buf, BT_L2CAP_BR_ECHO_RSP_RESERVE)`

		 * when allocating buffers intended for bt_l2cap_br_echo_rsp().

		 */

		LOG_ERR("Not enough headroom in buf %p", buf);

		return -EINVAL;

	}



	chan = bt_l2cap_br_lookup_rx_cid(conn, BT_L2CAP_CID_BR_SIG);

	if (chan == NULL) {

		LOG_ERR("Signaling Channel %u not found", BT_L2CAP_CID_BR_SIG);

		return -ENOTCONN;

	}



	hdr = net_buf_push(buf, sizeof(*hdr));



	hdr->code = BT_L2CAP_ECHO_RSP;

	hdr->ident = identifier;

	hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));



	return bt_l2cap_br_send_cb(conn, BT_L2CAP_CID_BR_SIG, buf, NULL, NULL);

}

subsys/bluetooth/host/classic/l2cap_br_internal.h

+10 −0
Original line number Diff line number Diff line
@@ -174,6 +174,16 @@ struct bt_l2cap_disconn_rsp { 
	uint16_t scid;

} __packed;



#define BT_L2CAP_ECHO_REQ               0x08

struct bt_l2cap_echo_req {

	uint8_t data[0];

} __packed;



#define BT_L2CAP_ECHO_RSP               0x09

struct bt_l2cap_echo_rsp {

	uint8_t data[0];

} __packed;



#define BT_L2CAP_INFO_FEAT_MASK         0x0002

#define BT_L2CAP_INFO_FIXED_CHAN        0x0003

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