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/** @file
* @brief Bluetooth connection handling
*/
/*
* Copyright (c) 2015-2016 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef __BT_CONN_H
#define __BT_CONN_H
/**
* @brief Connection management
* @defgroup bt_conn Connection management
* @ingroup bluetooth
* @{
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <stdbool.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
/** Opaque type representing a connection to a remote device */
struct bt_conn;
/** Connection parameters for LE connections */
struct bt_le_conn_param {
uint16_t interval_min;
uint16_t interval_max;
uint16_t latency;
uint16_t timeout;
};
/** Helper to declare connection parameters inline
*
* @param int_min Minimum Connection Interval (N * 1.25 ms)
* @param int_max Maximum Connection Interval (N * 1.25 ms)
* @param lat Connection Latency
* @param to Supervision Timeout (N * 10 ms)
*/
#define BT_LE_CONN_PARAM(int_min, int_max, lat, to) \
(&(struct bt_le_conn_param) { \
.interval_min = (int_min), \
.interval_max = (int_max), \
.latency = (lat), \
.timeout = (to), \
})
/** Default LE connection parameters:
* Connection Interval: 30-50 ms
* Latency: 0
* Timeout: 4 s
*/
#define BT_LE_CONN_PARAM_DEFAULT BT_LE_CONN_PARAM(BT_GAP_INIT_CONN_INT_MIN, \
BT_GAP_INIT_CONN_INT_MAX, \
0, 400)
/** @brief Increment a connection's reference count.
*
* Increment the reference count of a connection object.
*
* @param conn Connection object.
*
* @return Connection object with incremented reference count.
*/
struct bt_conn *bt_conn_ref(struct bt_conn *conn);
/** @brief Decrement a connection's reference count.
*
* Decrement the reference count of a connection object.
*
* @param conn Connection object.
*/
void bt_conn_unref(struct bt_conn *conn);
/** @brief Look up an existing connection by address.
*
* Look up an existing connection based on the remote address.
*
* @param peer Remote address.
*
* @return Connection object or NULL if not found. The caller gets a
* new reference to the connection object which must be released with
* bt_conn_unref() once done using the object.
*/
struct bt_conn *bt_conn_lookup_addr_le(const bt_addr_le_t *peer);
/** @brief Get destination (peer) address of a connection.
*
* @param conn Connection object.
*
* @return Destination address.
*/
const bt_addr_le_t *bt_conn_get_dst(const struct bt_conn *conn);
/** Connection Type */
enum {
/** LE Connection Type */
BT_CONN_TYPE_LE,
/** BR/EDR Connection Type */
BT_CONN_TYPE_BR,
/** SCO Connection Type */
BT_CONN_TYPE_SCO,
};
/** LE Connection Info Structure */
struct bt_conn_le_info {
const bt_addr_le_t *src; /** Source Address */
const bt_addr_le_t *dst; /** Destination Address */
uint16_t interval; /** Connection interval */
uint16_t latency; /** Connection slave latency */
uint16_t timeout; /** Connection supervision timeout */
};
/** BR/EDR Connection Info Structure */
struct bt_conn_br_info {
const bt_addr_t *dst; /** Destination BR/EDR address */
};
/** Connection role (master or slave) */
enum {
BT_CONN_ROLE_MASTER,
BT_CONN_ROLE_SLAVE,
};
/** @brief Connection Info Structure
*
*
* @param type Connection Type
* @param role Connection Role
* @param le LE Connection specific Info
* @param br BR/EDR Connection specific Info
*/
struct bt_conn_info {
uint8_t type;
uint8_t role;
union {
struct bt_conn_le_info le;
struct bt_conn_br_info br;
};
};
/** @brief Get connection info
*
* @param conn Connection object.
* @param info Connection info object.
*
* @return Zero on success or (negative) error code on failure.
*/
int bt_conn_get_info(const struct bt_conn *conn, struct bt_conn_info *info);
/** @brief Update the connection parameters.
*
* @param conn Connection object.
* @param param Updated connection parameters.
*
* @return Zero on success or (negative) error code on failure.
*/
int bt_conn_le_param_update(struct bt_conn *conn,
const struct bt_le_conn_param *param);
/** @brief Disconnect from a remote device or cancel pending connection.
*
* Disconnect an active connection with the specified reason code or cancel
* pending outgoing connection.
*
* @param conn Connection to disconnect.
* @param reason Reason code for the disconnection.
*
* @return Zero on success or (negative) error code on failure.
*/
int bt_conn_disconnect(struct bt_conn *conn, uint8_t reason);
/** @brief Initiate an LE connection to a remote device.
*
* Allows initiate new LE link to remote peer using its address.
* Returns a new reference that the the caller is responsible for managing.
*
* @param peer Remote address.
* @param param Initial connection parameters.
*
* @return Valid connection object on success or NULL otherwise.
*/
struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer,
const struct bt_le_conn_param *param);
/** @brief Automatically connect to remote device if it's in range.
*
* This function enables/disables automatic connection initiation.
* Everytime the device looses the connection with peer, this connection
* will be re-established if connectable advertisement from peer is received.
*
* @param addr Remote Bluetooth address.
* @param param If non-NULL, auto connect is enabled with the given
* parameters. If NULL, auto connect is disabled.
*
* @return Zero on success or error code otherwise.
*/
int bt_le_set_auto_conn(bt_addr_le_t *addr,
const struct bt_le_conn_param *param);
/** @brief Initiate directed advertising to a remote device
*
* Allows initiating a new LE connection to remote peer with the remote
* acting in central role and the local device in peripheral role.
*
* The advertising type must be either BT_LE_ADV_DIRECT_IND or
* BT_LE_ADV_DIRECT_IND_LOW_DUTY.
*
* In case of high duty cycle this will result in a callback with
* connected() with a new connection or with an error.
*
* The advertising may be cancelled with bt_conn_disconnect().
*
* Returns a new reference that the the caller is responsible for managing.
*
* @param peer Remote address.
* @param param Directed advertising parameters.
*
* @return Valid connection object on success or NULL otherwise.
*/
struct bt_conn *bt_conn_create_slave_le(const bt_addr_le_t *peer,
const struct bt_le_adv_param *param);
/** Security level. */
typedef enum __packed {
/** Only for BR/EDR special cases, like SDP */
BT_SECURITY_NONE,
/** No encryption and no authentication. */
BT_SECURITY_LOW,
/** Encryption and no authentication (no MITM). */
BT_SECURITY_MEDIUM,
/** Encryption and authentication (MITM). */
BT_SECURITY_HIGH,
/** Authenticated Secure Connections */
BT_SECURITY_FIPS,
} bt_security_t;
/** @brief Set security level for a connection.
*
* This function enable security (encryption) for a connection. If device is
* already paired with sufficiently strong key encryption will be enabled. If
* link is already encrypted with sufficiently strong key this function does
* nothing.
*
* If device is not paired pairing will be initiated. If device is paired and
* keys are too weak but input output capabilities allow for strong enough keys
* pairing will be initiated.
*
* This function may return error if required level of security is not possible
* to achieve due to local or remote device limitation (eg input output
* capabilities).
*
* @param conn Connection object.
* @param sec Requested security level.
*
* @return 0 on success or negative error
*/
int bt_conn_security(struct bt_conn *conn, bt_security_t sec);
/** @brief Get encryption key size.
*
* This function gets encryption key size.
* If there is no security (encryption) enabled 0 will be returned.
*
* @param conn Existing connection object.
*
* @return Encryption key size.
*/
uint8_t bt_conn_enc_key_size(struct bt_conn *conn);
/** @brief Connection callback structure.
*
* This structure is used for tracking the state of a connection.
* It is registered with the help of the bt_conn_cb_register() API.
* It's premissible to register multiple instances of this @ref bt_conn_cb
* type, in case different modules of an application are interested in
* tracking the connection state. 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_conn_cb {
/** @brief A new connection has been established.
*
* This callback notifies the application of a new connection.
* In case the err parameter is non-zero it means that the
* connection establishment failed.
*
* @param conn New connection object.
* @param err HCI error. Zero for success, non-zero otherwise.
*/
void (*connected)(struct bt_conn *conn, uint8_t err);
/** @brief A connection has been disconnected.
*
* This callback notifies the application that a connection
* has been disconnected.
*
* @param conn Connection object.
* @param reason HCI reason for the disconnection.
*/
void (*disconnected)(struct bt_conn *conn, uint8_t reason);
/** @brief LE connection parameter update request.
*
* This callback notifies the application that a remote device
* is requesting to update the connection parameters. The
* application accepts the parameters by returning true, or
* rejects them by returning false. Before accepting, the
* application may also adjust the parameters to better suit
* its needs.
*
* It is recommended for an application to have just one of these
* callbacks for simplicity. However, if an application registers
* multiple it needs to manage the potentially different
* requirements for each callback. Each callback gets the
* parameters as returned by previous callbacks, i.e. they are not
* necessarily the same ones as the remote originally sent.
*
* @param conn Connection object.
* @param param Proposed connection parameters.
*
* @return true to accept the parameters, or false to reject them.
*/
bool (*le_param_req)(struct bt_conn *conn,
struct bt_le_conn_param *param);
/** @brief The parameters for an LE connection have been updated.
*
* This callback notifies the application that the connection
* parameters for an LE connection have been updated.
*
* @param conn Connection object.
* @param interval Connection interval.
* @param latency Connection latency.
* @param timeout Connection supervision timeout.
*/
void (*le_param_updated)(struct bt_conn *conn, uint16_t interval,
uint16_t latency, uint16_t timeout);
#if defined(CONFIG_BLUETOOTH_SMP)
/** @brief Remote Identity Address has been resolved.
*
* This callback notifies the application that a remote
* Identity Address has been resolved
*
* @param conn Connection object.
* @param rpa Resolvable Private Address.
* @param identity Identity Address.
*/
void (*identity_resolved)(struct bt_conn *conn,
const bt_addr_le_t *rpa,
const bt_addr_le_t *identity);
#endif /* CONFIG_BLUETOOTH_SMP */
#if defined(CONFIG_BLUETOOTH_SMP) || defined(CONFIG_BLUETOOTH_BREDR)
/** @brief The security level of a connection has changed.
*
* This callback notifies the application that the security level
* of a connection has changed.
*
* @param conn Connection object.
* @param level New security level of the connection.
*/
void (*security_changed)(struct bt_conn *conn, bt_security_t level);
#endif /* defined(CONFIG_BLUETOOTH_SMP) || defined(CONFIG_BLUETOOTH_BREDR) */
struct bt_conn_cb *_next;
};
/** @brief Register connection callbacks.
*
* Register callbacks to monitor the state of connections.
*
* @param cb Callback struct.
*/
void bt_conn_cb_register(struct bt_conn_cb *cb);
/** Authenticated pairing callback structure */
struct bt_conn_auth_cb {
void (*passkey_display)(struct bt_conn *conn, unsigned int passkey);
void (*passkey_entry)(struct bt_conn *conn);
void (*passkey_confirm)(struct bt_conn *conn, unsigned int passkey);
void (*cancel)(struct bt_conn *conn);
void (*pairing_confirm)(struct bt_conn *conn);
#if defined(CONFIG_BLUETOOTH_BREDR)
void (*pincode_entry)(struct bt_conn *conn, bool highsec);
#endif
};
/** @brief Register authentication callbacks.
*
* Register callbacks to handle authenticated pairing. Passing NULL unregisters
* previous callbacks structure.
*
* @param cb Callback struct.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_cb_register(const struct bt_conn_auth_cb *cb);
/** @brief Reply with entered passkey.
*
* This function should be called only after passkey_entry callback from
* bt_conn_auth_cb structure was called.
*
* @param conn Connection object.
* @param passkey Entered passkey.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_passkey_entry(struct bt_conn *conn, unsigned int passkey);
/** @brief Cancel ongoing authenticated pairing.
*
* This function allows to cancel ongoing authenticated pairing.
*
* @param conn Connection object.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_cancel(struct bt_conn *conn);
/** @brief Reply if passkey was confirmed to match by user.
*
* This function should be called only after passkey_confirm callback from
* bt_conn_auth_cb structure was called.
*
* @param conn Connection object.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_passkey_confirm(struct bt_conn *conn);
/** @brief Reply if incoming pairing was confirmed by user.
*
* This function should be called only after pairing_confirm callback from
* bt_conn_auth_cb structure was called if user confirmed incoming pairing.
*
* @param conn Connection object.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_pairing_confirm(struct bt_conn *conn);
/** @brief Reply with entered PIN code.
*
* This function should be called only after PIN code callback from
* bt_conn_auth_cb structure was called. It's for legacy 2.0 devices.
*
* @param conn Connection object.
* @param pin Entered PIN code.
*
* @return Zero on success or negative error code otherwise
*/
int bt_conn_auth_pincode_entry(struct bt_conn *conn, const char *pin);
/** Connection parameters for BR/EDR connections */
struct bt_br_conn_param {
bool allow_role_switch;
};
/** Helper to declare BR/EDR connection parameters inline
*
* @param role_switch True if role switch is allowed
*/
#define BT_BR_CONN_PARAM(role_switch) \
(&(struct bt_br_conn_param) { \
.allow_role_switch = (role_switch), \
})
/** Default BR/EDR connection parameters:
* Role switch allowed
*/
#define BT_BR_CONN_PARAM_DEFAULT BT_BR_CONN_PARAM(true)
/** @brief Initiate an BR/EDR connection to a remote device.
*
* Allows initiate new BR/EDR link to remote peer using its address.
* Returns a new reference that the the caller is responsible for managing.
*
* @param peer Remote address.
* @param param Initial connection parameters.
*
* @return Valid connection object on success or NULL otherwise.
*/
struct bt_conn *bt_conn_create_br(const bt_addr_t *peer,
const struct bt_br_conn_param *param);
/** @brief Initiate an SCO connection to a remote device.
*
* Allows initiate new SCO link to remote peer using its address.
* Returns a new reference that the the caller is responsible for managing.
*
* @param peer Remote address.
*
* @return Valid connection object on success or NULL otherwise.
*/
struct bt_conn *bt_conn_create_sco(const bt_addr_t *peer);
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#endif /* __BT_CONN_H */