/** @file
* @brief Bluetooth L2CAP handling
*/
/*
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_H_
#define ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_H_
/**
* @brief L2CAP
* @defgroup bt_l2cap L2CAP
* @ingroup bluetooth
* @{
*/
#include <sys/atomic.h>
#include <bluetooth/buf.h>
#include <bluetooth/conn.h>
#include <bluetooth/hci.h>
#ifdef __cplusplus
extern "C" {
#endif
/** L2CAP PDU header size, used for buffer size calculations */
#define BT_L2CAP_HDR_SIZE 4
/** Maximum Transmission Unit (MTU) for an outgoing L2CAP PDU. */
#define BT_L2CAP_TX_MTU (CONFIG_BT_L2CAP_TX_MTU)
/** Maximum Transmission Unit (MTU) for an incoming L2CAP PDU. */
#define BT_L2CAP_RX_MTU (CONFIG_BT_BUF_ACL_RX_SIZE - BT_L2CAP_HDR_SIZE)
/** @brief Helper to calculate needed buffer size for L2CAP PDUs.
* Useful for creating buffer pools.
*
* @param mtu Needed L2CAP PDU MTU.
*
* @return Needed buffer size to match the requested L2CAP PDU MTU.
*/
#define BT_L2CAP_BUF_SIZE(mtu) BT_BUF_ACL_SIZE(BT_L2CAP_HDR_SIZE + (mtu))
/** L2CAP SDU header size, used for buffer size calculations */
#define BT_L2CAP_SDU_HDR_SIZE 2
/** @brief Maximum Transmission Unit for an unsegmented outgoing L2CAP SDU.
*
* The Maximum Transmission Unit for an outgoing L2CAP SDU when sent without
* segmentation, i.e a single L2CAP SDU will fit inside a single L2CAP PDU.
*
* The MTU for outgoing L2CAP SDUs with segmentation is defined by the
* size of the application buffer pool.
*/
#define BT_L2CAP_SDU_TX_MTU (BT_L2CAP_TX_MTU - BT_L2CAP_SDU_HDR_SIZE)
/** @brief Maximum Transmission Unit for an unsegmented incoming L2CAP SDU.
*
* The Maximum Transmission Unit for an incoming L2CAP SDU when sent without
* segmentation, i.e a single L2CAP SDU will fit inside a single L2CAP PDU.
*
* The MTU for incoming L2CAP SDUs with segmentation is defined by the
* size of the application buffer pool. The application will have to define
* an alloc_buf callback for the channel in order to support receiving
* segmented L2CAP SDUs.
*/
#define BT_L2CAP_SDU_RX_MTU (BT_L2CAP_RX_MTU - BT_L2CAP_SDU_HDR_SIZE)
/** @def BT_L2CAP_SDU_BUF_SIZE
*
* @brief Helper to calculate needed buffer size for L2CAP SDUs.
* Useful for creating buffer pools.
*
* @param mtu Required BT_L2CAP_*_SDU.
*
* @return Needed buffer size to match the requested L2CAP SDU MTU.
*/
#define BT_L2CAP_SDU_BUF_SIZE(mtu) BT_L2CAP_BUF_SIZE(BT_L2CAP_SDU_HDR_SIZE + (mtu))
struct bt_l2cap_chan;
/** @typedef bt_l2cap_chan_destroy_t
* @brief Channel destroy callback
*
* @param chan Channel object.
*/
typedef void (*bt_l2cap_chan_destroy_t)(struct bt_l2cap_chan *chan);
/** @brief Life-span states of L2CAP CoC channel.
*
* Used only by internal APIs dealing with setting channel to proper state
* depending on operational context.
*/
typedef enum bt_l2cap_chan_state {
/** Channel disconnected */
BT_L2CAP_DISCONNECTED,
/** Channel in connecting state */
BT_L2CAP_CONNECT,
/** Channel in config state, BR/EDR specific */
BT_L2CAP_CONFIG,
/** Channel ready for upper layer traffic on it */
BT_L2CAP_CONNECTED,
/** Channel in disconnecting state */
BT_L2CAP_DISCONNECT,
} __packed bt_l2cap_chan_state_t;
/** @brief Status of L2CAP channel. */
typedef enum bt_l2cap_chan_status {
/** Channel output status */
BT_L2CAP_STATUS_OUT,
/** @brief Channel shutdown status
*
* Once this status is notified it means the channel will no longer be
* able to transmit or receive data.
*/
BT_L2CAP_STATUS_SHUTDOWN,
/** @brief Channel encryption pending status */
BT_L2CAP_STATUS_ENCRYPT_PENDING,
/* Total number of status - must be at the end of the enum */
BT_L2CAP_NUM_STATUS,
} __packed bt_l2cap_chan_status_t;
/** @brief L2CAP Channel structure. */
struct bt_l2cap_chan {
/** Channel connection reference */
struct bt_conn *conn;
/** Channel operations reference */
const struct bt_l2cap_chan_ops *ops;
sys_snode_t node;
bt_l2cap_chan_destroy_t destroy;
/* Response Timeout eXpired (RTX) timer */
struct k_work_delayable rtx_work;
struct k_work_sync rtx_sync;
ATOMIC_DEFINE(status, BT_L2CAP_NUM_STATUS);
#if defined(CONFIG_BT_L2CAP_DYNAMIC_CHANNEL)
bt_l2cap_chan_state_t state;
/** Remote PSM to be connected */
uint16_t psm;
/** Helps match request context during CoC */
uint8_t ident;
bt_security_t required_sec_level;
#endif /* CONFIG_BT_L2CAP_DYNAMIC_CHANNEL */
};
/** @brief LE L2CAP Endpoint structure. */
struct bt_l2cap_le_endpoint {
/** Endpoint Channel Identifier (CID) */
uint16_t cid;
/** Endpoint Maximum Transmission Unit */
uint16_t mtu;
/** Endpoint Maximum PDU payload Size */
uint16_t mps;
/** Endpoint initial credits */
uint16_t init_credits;
/** Endpoint credits */
atomic_t credits;
};
/** @brief LE L2CAP Channel structure. */
struct bt_l2cap_le_chan {
/** Common L2CAP channel reference object */
struct bt_l2cap_chan chan;
/** @brief Channel Receiving Endpoint.
*
* If the application has set an alloc_buf channel callback for the
* channel to support receiving segmented L2CAP SDUs the application
* should inititalize the MTU of the Receiving Endpoint. Otherwise the
* MTU of the receiving endpoint will be initialized to
* @ref BT_L2CAP_SDU_RX_MTU by the stack.
*/
struct bt_l2cap_le_endpoint rx;
/** Pending RX MTU on ECFC reconfigure, used internally by stack */
uint16_t pending_rx_mtu;
/** Channel Transmission Endpoint */
struct bt_l2cap_le_endpoint tx;
/** Channel Transmission queue */
struct k_fifo tx_queue;
/** Channel Pending Transmission buffer */
struct net_buf *tx_buf;
/** Channel Transmission work */
struct k_work tx_work;
/** Segment SDU packet from upper layer */
struct net_buf *_sdu;
uint16_t _sdu_len;
struct k_work rx_work;
struct k_fifo rx_queue;
};
/** @def BT_L2CAP_LE_CHAN(_ch)
* @brief Helper macro getting container object of type bt_l2cap_le_chan
* address having the same container chan member address as object in question.
*
* @param _ch Address of object of bt_l2cap_chan type
*
* @return Address of in memory bt_l2cap_le_chan object type containing
* the address of in question object.
*/
#define BT_L2CAP_LE_CHAN(_ch) CONTAINER_OF(_ch, struct bt_l2cap_le_chan, chan)
/** @brief BREDR L2CAP Endpoint structure. */
struct bt_l2cap_br_endpoint {
/** Endpoint Channel Identifier (CID) */
uint16_t cid;
/** Endpoint Maximum Transmission Unit */
uint16_t mtu;
};
/** @brief BREDR L2CAP Channel structure. */
struct bt_l2cap_br_chan {
/** Common L2CAP channel reference object */
struct bt_l2cap_chan chan;
/** Channel Receiving Endpoint */
struct bt_l2cap_br_endpoint rx;
/** Channel Transmission Endpoint */
struct bt_l2cap_br_endpoint tx;
/* For internal use only */
atomic_t flags[1];
};
/** @brief L2CAP Channel operations structure. */
struct bt_l2cap_chan_ops {
/** @brief Channel connected callback
*
* If this callback is provided it will be called whenever the
* connection completes.
*
* @param chan The channel that has been connected
*/
void (*connected)(struct bt_l2cap_chan *chan);
/** @brief Channel disconnected callback
*
* If this callback is provided it will be called whenever the
* channel is disconnected, including when a connection gets
* rejected.
*
* @param chan The channel that has been Disconnected
*/
void (*disconnected)(struct bt_l2cap_chan *chan);
/** @brief Channel encrypt_change callback
*
* If this callback is provided it will be called whenever the
* security level changed (indirectly link encryption done) or
* authentication procedure fails. In both cases security initiator
* and responder got the final status (HCI status) passed by
* related to encryption and authentication events from local host's
* controller.
*
* @param chan The channel which has made encryption status changed.
* @param status HCI status of performed security procedure caused
* by channel security requirements. The value is populated
* by HCI layer and set to 0 when success and to non-zero (reference to
* HCI Error Codes) when security/authentication failed.
*/
void (*encrypt_change)(struct bt_l2cap_chan *chan, uint8_t hci_status);
/** @brief Channel alloc_buf callback
*
* If this callback is provided the channel will use it to allocate
* buffers to store incoming data. Channels that requires segmentation
* must set this callback.
* If the application has not set a callback the L2CAP SDU MTU will be
* truncated to @ref BT_L2CAP_SDU_RX_MTU.
*
* @param chan The channel requesting a buffer.
*
* @return Allocated buffer.
*/
struct net_buf *(*alloc_buf)(struct bt_l2cap_chan *chan);
/** @brief Channel recv callback
*
* @param chan The channel receiving data.
* @param buf Buffer containing incoming data.
*
* @return 0 in case of success or negative value in case of error.
* @return -EINPROGRESS in case where user has to confirm once the data
* has been processed by calling
* @ref bt_l2cap_chan_recv_complete passing back
* the buffer received with its original user_data
* which contains the number of segments/credits
* used by the packet.
*/
int (*recv)(struct bt_l2cap_chan *chan, struct net_buf *buf);
/** @brief Channel sent callback
*
* If this callback is provided it will be called whenever a SDU has
* been completely sent.
*
* @param chan The channel which has sent data.
*/
void (*sent)(struct bt_l2cap_chan *chan);
/** @brief Channel status callback
*
* If this callback is provided it will be called whenever the
* channel status changes.
*
* @param chan The channel which status changed
* @param status The channel status
*/
void (*status)(struct bt_l2cap_chan *chan, atomic_t *status);
/* @brief Channel released callback
*
* If this callback is set it is called when the stack has release all
* references to the channel object.
*/
void (*released)(struct bt_l2cap_chan *chan);
/** @brief Channel reconfigured callback
*
* If this callback is provided it will be called whenever peer or
* local device requested reconfiguration. Application may check
* updated MTU and MPS values by inspecting chan->le endpoints.
*
* @param chan The channel which was reconfigured
*/
void (*reconfigured)(struct bt_l2cap_chan *chan);
};
/** @def BT_L2CAP_CHAN_SEND_RESERVE
* @brief Headroom needed for outgoing L2CAP PDUs.
*/
#define BT_L2CAP_CHAN_SEND_RESERVE (BT_L2CAP_BUF_SIZE(0))
/** @def BT_L2CAP_SDU_CHAN_SEND_RESERVE
* @brief Headroom needed for outgoing L2CAP SDUs.
*/
#define BT_L2CAP_SDU_CHAN_SEND_RESERVE (BT_L2CAP_SDU_BUF_SIZE(0))
/** @brief L2CAP Server structure. */
struct bt_l2cap_server {
/** @brief Server PSM.
*
* Possible values:
* 0 A dynamic value will be auto-allocated when
* bt_l2cap_server_register() is called.
*
* 0x0001-0x007f Standard, Bluetooth SIG-assigned fixed values.
*
* 0x0080-0x00ff 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 Server accept callback
*
* This callback is called whenever a new incoming connection requires
* authorization.
*
* @param conn The connection that is requesting authorization
* @param chan Pointer to received the allocated channel
*
* @return 0 in case of success or negative value in case of error.
* @return -ENOMEM if no available space for new channel.
* @return -EACCES if application did not authorize the connection.
* @return -EPERM if encryption key size is too short.
*/
int (*accept)(struct bt_conn *conn, struct bt_l2cap_chan **chan);
sys_snode_t node;
};
/** @brief Register L2CAP server.
*
* Register L2CAP server for a PSM, each new connection is authorized using
* the accept() callback which in case of success shall allocate the channel
* structure to be used by the new connection.
*
* For fixed, SIG-assigned PSMs (in the range 0x0001-0x007f) the PSM should
* be assigned to server->psm before calling this API. For dynamic PSMs
* (in the range 0x0080-0x00ff) server->psm may be pre-set to a given value
* (this is however not recommended) or be left as 0, in which case upon
* return a newly allocated value will have been assigned to it. For
* dynamically allocated values the expectation is that it's exposed through
* a GATT service, and that's how L2CAP clients discover how to connect to
* the server.
*
* @param server Server structure.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_server_register(struct bt_l2cap_server *server);
/** @brief Register L2CAP server on BR/EDR oriented connection.
*
* Register L2CAP server for a PSM, each new connection is authorized using
* the accept() callback which in case of success shall allocate the channel
* structure to be used by the new connection.
*
* @param server Server structure.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_br_server_register(struct bt_l2cap_server *server);
/** @brief Connect Enhanced Credit Based L2CAP channels
*
* Connect up to 5 L2CAP channels by PSM, once the connection is completed
* each channel connected() callback will be called. If the connection is
* rejected disconnected() callback is called instead.
*
* @param conn Connection object.
* @param chans Array of channel objects.
* @param psm Channel PSM to connect to.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_ecred_chan_connect(struct bt_conn *conn,
struct bt_l2cap_chan **chans, uint16_t psm);
/** @brief Reconfigure Enhanced Credit Based L2CAP channels
*
* Reconfigure up to 5 L2CAP channels. Channels must be from the same bt_conn.
* Once reconfiguration is completed each channel reconfigured() callback will
* be called. MTU cannot be decreased on any of provided channels.
*
* @param chans Array of channel objects. Null-terminated. Elements after the
* first 5 are silently ignored.
* @param mtu Channel MTU to reconfigure to.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_ecred_chan_reconfigure(struct bt_l2cap_chan **chans, uint16_t mtu);
/** @brief Connect L2CAP channel
*
* Connect L2CAP channel by PSM, once the connection is completed channel
* connected() callback will be called. If the connection is rejected
* disconnected() callback is called instead.
* Channel object passed (over an address of it) as second parameter shouldn't
* be instantiated in application as standalone. Instead of, application should
* create transport dedicated L2CAP objects, i.e. type of bt_l2cap_le_chan for
* LE and/or type of bt_l2cap_br_chan for BR/EDR. Then pass to this API
* the location (address) of bt_l2cap_chan type object which is a member
* of both transport dedicated objects.
*
* @param conn Connection object.
* @param chan Channel object.
* @param psm Channel PSM to connect to.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_chan_connect(struct bt_conn *conn, struct bt_l2cap_chan *chan,
uint16_t psm);
/** @brief Disconnect L2CAP channel
*
* Disconnect L2CAP channel, if the connection is pending it will be
* canceled and as a result the channel disconnected() callback is called.
* Regarding to input parameter, to get details see reference description
* to bt_l2cap_chan_connect() API above.
*
* @param chan Channel object.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_chan_disconnect(struct bt_l2cap_chan *chan);
/** @brief Send data to L2CAP channel
*
* Send data from buffer to the channel. If credits are not available, buf will
* be queued and sent as and when credits are received from peer.
* Regarding to first input parameter, to get details see reference description
* to bt_l2cap_chan_connect() API above.
*
* When sending L2CAP data over an BR/EDR connection the application is sending
* L2CAP PDUs. The application is required to have reserved
* @ref BT_L2CAP_CHAN_SEND_RESERVE bytes in the buffer before sending.
* The application should use the BT_L2CAP_BUF_SIZE() helper to correctly
* size the buffers for the for the outgoing buffer pool.
*
* When sending L2CAP data over an LE connection the applicatios is sending
* L2CAP SDUs. The application can optionally reserve
* @ref BT_L2CAP_SDU_CHAN_SEND_RESERVE bytes in the buffer before sending.
* By reserving bytes in the buffer the stack can use this buffer as a segment
* directly, otherwise it will have to allocate a new segment for the first
* segment.
* If the application is reserving the bytes it should use the
* BT_L2CAP_BUF_SIZE() helper to correctly size the buffers for the for the
* outgoing buffer pool.
* When segmenting an L2CAP SDU into L2CAP PDUs the stack will first attempt
* to allocate buffers from the original buffer pool of the L2CAP SDU before
* using the stacks own buffer pool.
*
* @note Buffer ownership is transferred to the stack in case of success, in
* case of an error the caller retains the ownership of the buffer.
*
* @return Bytes sent in case of success or negative value in case of error.
*/
int bt_l2cap_chan_send(struct bt_l2cap_chan *chan, struct net_buf *buf);
/** @brief Complete receiving L2CAP channel data
*
* Complete the reception of incoming data. This shall only be called if the
* channel recv callback has returned -EINPROGRESS to process some incoming
* data. The buffer shall contain the original user_data as that is used for
* storing the credits/segments used by the packet.
*
* @param chan Channel object.
* @param buf Buffer containing the data.
*
* @return 0 in case of success or negative value in case of error.
*/
int bt_l2cap_chan_recv_complete(struct bt_l2cap_chan *chan,
struct net_buf *buf);
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#endif /* ZEPHYR_INCLUDE_BLUETOOTH_L2CAP_H_ */