text: /** @file
   *  @brief Bluetooth connection handling
   */
  
  /*
   * Copyright (c) 2015-2016 Intel Corporation
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  #ifndef ZEPHYR_INCLUDE_BLUETOOTH_CONN_H_
  #define ZEPHYR_INCLUDE_BLUETOOTH_CONN_H_
  
  /**
   * @brief Connection management
   * @defgroup bt_conn Connection management
   * @ingroup bluetooth
   * @{
   */
  
  #include <stdbool.h>
  
  #include <bluetooth/bluetooth.h>
  #include <bluetooth/hci_err.h>
  #include <bluetooth/addr.h>
  #include <bluetooth/gap.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /** 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;
  };
  
  /** @brief Initialize connection parameters
   *
   *  @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_INIT(int_min, int_max, lat, to) \
  { \
  	.interval_min = (int_min), \
  	.interval_max = (int_max), \
  	.latency = (lat), \
  	.timeout = (to), \
  }
  
  /** 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[]) { \
  		BT_LE_CONN_PARAM_INIT(int_min, int_max, lat, 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)
  
  /** Connection PHY information for LE connections */
  struct bt_conn_le_phy_info {
  	uint8_t tx_phy; /** Connection transmit PHY */
  	uint8_t rx_phy; /** Connection receive PHY */
  };
  
  /** Connection PHY options */
  enum {
  	/** Convenience value when no options are specified. */
  	BT_CONN_LE_PHY_OPT_NONE = 0,
  
  	/** LE Coded using S=2 coding preferred when transmitting. */
  	BT_CONN_LE_PHY_OPT_CODED_S2  = BIT(0),
  
  	/** LE Coded using S=8 coding preferred when transmitting. */
  	BT_CONN_LE_PHY_OPT_CODED_S8  = BIT(1),
  };
  
  /** Preferred PHY parameters for LE connections */
  struct bt_conn_le_phy_param {
  	uint16_t options;     /** Connection PHY options. */
  	uint8_t  pref_tx_phy; /** Bitmask of preferred transmit PHYs */
  	uint8_t  pref_rx_phy; /** Bitmask of preferred receive PHYs */
  };
  
  /** Initialize PHY parameters
   *
   * @param _pref_tx_phy Bitmask of preferred transmit PHYs.
   * @param _pref_rx_phy Bitmask of preferred receive PHYs.
   */
  #define BT_CONN_LE_PHY_PARAM_INIT(_pref_tx_phy, _pref_rx_phy) \
  { \
  	.options = BT_CONN_LE_PHY_OPT_NONE, \
  	.pref_tx_phy = (_pref_tx_phy), \
  	.pref_rx_phy = (_pref_rx_phy), \
  }
  
  /** Helper to declare PHY parameters inline
   *
   * @param _pref_tx_phy Bitmask of preferred transmit PHYs.
   * @param _pref_rx_phy Bitmask of preferred receive PHYs.
   */
  #define BT_CONN_LE_PHY_PARAM(_pref_tx_phy, _pref_rx_phy) \
  	((struct bt_conn_le_phy_param []) { \
  		BT_CONN_LE_PHY_PARAM_INIT(_pref_tx_phy, _pref_rx_phy) \
  	 })
  
  /** Only LE 1M PHY */
  #define BT_CONN_LE_PHY_PARAM_1M BT_CONN_LE_PHY_PARAM(BT_GAP_LE_PHY_1M, \
  						     BT_GAP_LE_PHY_1M)
  
  /** Only LE 2M PHY */
  #define BT_CONN_LE_PHY_PARAM_2M BT_CONN_LE_PHY_PARAM(BT_GAP_LE_PHY_2M, \
  						     BT_GAP_LE_PHY_2M)
  
  /** Only LE Coded PHY. */
  #define BT_CONN_LE_PHY_PARAM_CODED BT_CONN_LE_PHY_PARAM(BT_GAP_LE_PHY_CODED, \
  							BT_GAP_LE_PHY_CODED)
  
  /** All LE PHYs. */
  #define BT_CONN_LE_PHY_PARAM_ALL BT_CONN_LE_PHY_PARAM(BT_GAP_LE_PHY_1M |   \
  						      BT_GAP_LE_PHY_2M |   \
  						      BT_GAP_LE_PHY_CODED, \
  						      BT_GAP_LE_PHY_1M |   \
  						      BT_GAP_LE_PHY_2M |   \
  						      BT_GAP_LE_PHY_CODED)
  
  /** Connection data length information for LE connections */
  struct bt_conn_le_data_len_info {
  	/** Maximum Link Layer transmission payload size in bytes. */
  	uint16_t tx_max_len;
  	/** Maximum Link Layer transmission payload time in us. */
  	uint16_t tx_max_time;
  	/** Maximum Link Layer reception payload size in bytes. */
  	uint16_t rx_max_len;
  	/** Maximum Link Layer reception payload time in us. */
  	uint16_t rx_max_time;
  };
  
  /** Connection data length parameters for LE connections */
  struct bt_conn_le_data_len_param {
  	/** Maximum Link Layer transmission payload size in bytes. */
  	uint16_t tx_max_len;
  	/** Maximum Link Layer transmission payload time in us. */
  	uint16_t tx_max_time;
  };
  
  /** Initialize transmit data length parameters
   *
   * @param  _tx_max_len  Maximum Link Layer transmission payload size in bytes.
   * @param  _tx_max_time Maximum Link Layer transmission payload time in us.
   */
  #define BT_CONN_LE_DATA_LEN_PARAM_INIT(_tx_max_len, _tx_max_time) \
  { \
  	.tx_max_len = (_tx_max_len), \
  	.tx_max_time = (_tx_max_time), \
  }
  
  /** Helper to declare transmit data length parameters inline
   *
   * @param  _tx_max_len  Maximum Link Layer transmission payload size in bytes.
   * @param  _tx_max_time Maximum Link Layer transmission payload time in us.
   */
  #define BT_CONN_LE_DATA_LEN_PARAM(_tx_max_len, _tx_max_time) \
  	((struct bt_conn_le_data_len_param[]) { \
  		BT_CONN_LE_DATA_LEN_PARAM_INIT(_tx_max_len, _tx_max_time) \
  	 })
  
  /** Default LE data length parameters. */
  #define BT_LE_DATA_LEN_PARAM_DEFAULT \
  	BT_CONN_LE_DATA_LEN_PARAM(BT_GAP_DATA_LEN_DEFAULT, \
  				  BT_GAP_DATA_TIME_DEFAULT)
  
  /** Maximum LE data length parameters. */
  #define BT_LE_DATA_LEN_PARAM_MAX \
  	BT_CONN_LE_DATA_LEN_PARAM(BT_GAP_DATA_LEN_MAX, \
  				  BT_GAP_DATA_TIME_MAX)
  
  /** @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 Iterate through all existing connections.
   *
   * @param type  Connection Type
   * @param func  Function to call for each connection.
   * @param data  Data to pass to the callback function.
   */
  void bt_conn_foreach(int type, void (*func)(struct bt_conn *conn, void *data),
  		     void *data);
  
  /** @brief Look up an existing connection by address.
   *
   *  Look up an existing connection based on the remote address.
   *
   *  The caller gets a new reference to the connection object which must be
   *  released with bt_conn_unref() once done using the object.
   *
   *  @param id   Local identity (in most cases BT_ID_DEFAULT).
   *  @param peer Remote address.
   *
   *  @return Connection object or NULL if not found.
   */
  struct bt_conn *bt_conn_lookup_addr_le(uint8_t id, 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);
  
  /** @brief Get array index of a connection
   *
   *  This function is used to map bt_conn to index of an array of
   *  connections. The array has CONFIG_BT_MAX_CONN elements.
   *
   *  @param conn Connection object.
   *
   *  @return Index of the connection object.
   *          The range of the returned value is 0..CONFIG_BT_MAX_CONN-1
   */
  uint8_t bt_conn_index(struct bt_conn *conn);
  
  /** Connection Type */
  enum {
  	/** LE Connection Type */
  	BT_CONN_TYPE_LE = BIT(0),
  	/** BR/EDR Connection Type */
  	BT_CONN_TYPE_BR = BIT(1),
  	/** SCO Connection Type */
  	BT_CONN_TYPE_SCO = BIT(2),
  	/** ISO Connection Type */
  	BT_CONN_TYPE_ISO = BIT(3),
  	/** All Connection Type */
  	BT_CONN_TYPE_ALL = BT_CONN_TYPE_LE | BT_CONN_TYPE_BR |
  			   BT_CONN_TYPE_SCO | BT_CONN_TYPE_ISO,
  };
  
  /** LE Connection Info Structure */
  struct bt_conn_le_info {
  	/** Source (Local) Identity Address */
  	const bt_addr_le_t *src;
  	/** Destination (Remote) Identity Address or remote Resolvable Private
  	 *  Address (RPA) before identity has been resolved.
  	 */
  	const bt_addr_le_t *dst;
  	/** Local device address used during connection setup. */
  	const bt_addr_le_t *local;
  	/** Remote device address used during connection setup. */
  	const bt_addr_le_t *remote;
  	uint16_t interval; /** Connection interval */
  	uint16_t latency; /** Connection slave latency */
  	uint16_t timeout; /** Connection supervision timeout */
  
  #if defined(CONFIG_BT_USER_PHY_UPDATE)
  	const struct bt_conn_le_phy_info      *phy;
  #endif /* defined(CONFIG_BT_USER_PHY_UPDATE) */
  
  #if defined(CONFIG_BT_USER_DATA_LEN_UPDATE)
  	/* Connection maximum single fragment parameters */
  	const struct bt_conn_le_data_len_info *data_len;
  #endif /* defined(CONFIG_BT_USER_DATA_LEN_UPDATE) */
  };
  
  /** BR/EDR Connection Info Structure */
  struct bt_conn_br_info {
  	const bt_addr_t *dst; /** Destination (Remote) BR/EDR address */
  };
  
  /** Connection role (master or slave) */
  enum {
  	BT_CONN_ROLE_MASTER,
  	BT_CONN_ROLE_SLAVE,
  };
  
  /** Connection Info Structure */
  struct bt_conn_info {
  	/** Connection Type. */
  	uint8_t type;
  	/** Connection Role. */
  	uint8_t role;
  	/** Which local identity the connection was created with */
  	uint8_t id;
  	/** Connection Type specific Info.*/
  	union {
  		/** LE Connection specific Info. */
  		struct bt_conn_le_info le;
  		/** BR/EDR Connection specific Info. */
  		struct bt_conn_br_info br;
  	};
  };
  
  /** LE Connection Remote Info Structure */
  struct bt_conn_le_remote_info {
  
  	/** Remote LE feature set (bitmask). */
  	const uint8_t *features;
  };
  
  /** BR/EDR Connection Remote Info structure */
  struct bt_conn_br_remote_info {
  
  	/** Remote feature set (pages of bitmasks). */
  	const uint8_t *features;
  
  	/** Number of pages in the remote feature set. */
  	uint8_t num_pages;
  };
  
  /** @brief Connection Remote Info Structure
   *
   *  @note The version, manufacturer and subversion fields will only contain
   *        valid data if :option:`CONFIG_BT_REMOTE_VERSION` is enabled.
   */
  struct bt_conn_remote_info {
  	/** Connection Type */
  	uint8_t  type;
  
  	/** Remote Link Layer version */
  	uint8_t  version;
  
  	/** Remote manufacturer identifier */
  	uint16_t manufacturer;
  
  	/** Per-manufacturer unique revision */
  	uint16_t subversion;
  
  	union {
  		/** LE connection remote info */
  		struct bt_conn_le_remote_info le;
  
  		/** BR/EDR connection remote info */
  		struct bt_conn_br_remote_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 Get connection info for the remote device.
   *
   *  @param conn Connection object.
   *  @param remote_info Connection remote info object.
   *
   *  @note In order to retrieve the remote version (version, manufacturer
   *  and subversion) :option:`CONFIG_BT_REMOTE_VERSION` must be enabled
   *
   *  @note The remote information is exchanged directly after the connection has
   *  been established. The application can be notified about when the remote
   *  information is available through the remote_info_available callback.
   *
   *  @return Zero on success or (negative) error code on failure.
   *  @return -EBUSY The remote information is not yet available.
   */
  int bt_conn_get_remote_info(struct bt_conn *conn,
  			    struct bt_conn_remote_info *remote_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 Update the connection transmit data length parameters.
   *
   *  @param conn  Connection object.
   *  @param param Updated data length parameters.
   *
   *  @return Zero on success or (negative) error code on failure.
   */
  int bt_conn_le_data_len_update(struct bt_conn *conn,
  			       const struct bt_conn_le_data_len_param *param);
  
  /** @brief Update the connection PHY parameters.
   *
   *  Update the preferred transmit and receive PHYs of the connection.
   *  Use @ref BT_GAP_LE_PHY_NONE to indicate no preference.
   *
   *  @param conn Connection object.
   *  @param param Updated connection parameters.
   *
   *  @return Zero on success or (negative) error code on failure.
   */
  int bt_conn_le_phy_update(struct bt_conn *conn,
  			  const struct bt_conn_le_phy_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);
  
  enum {
  	/** Convenience value when no options are specified. */
  	BT_CONN_LE_OPT_NONE = 0,
  
  	/** @brief Enable LE Coded PHY.
  	 *
  	 *  Enable scanning on the LE Coded PHY.
  	 */
  	BT_CONN_LE_OPT_CODED = BIT(0),
  
  	/** @brief Disable LE 1M PHY.
  	 *
  	 *  Disable scanning on the LE 1M PHY.
  	 *
  	 *  @note Requires @ref BT_CONN_LE_OPT_CODED.
  	 */
  	BT_CONN_LE_OPT_NO_1M = BIT(1),
  };
  
  struct bt_conn_le_create_param {
  
  	/** Bit-field of create connection options. */
  	uint32_t options;
  
  	/** Scan interval (N * 0.625 ms) */
  	uint16_t interval;
  
  	/** Scan window (N * 0.625 ms) */
  	uint16_t window;
  
  	/** @brief Scan interval LE Coded PHY (N * 0.625 MS)
  	 *
  	 *  Set zero to use same as LE 1M PHY scan interval
  	 */
  	uint16_t interval_coded;
  
  	/** @brief Scan window LE Coded PHY (N * 0.625 MS)
  	 *
  	 *  Set zero to use same as LE 1M PHY scan window.
  	 */
  	uint16_t window_coded;
  
  	/** @brief Connection initiation timeout (N * 10 MS)
  	 *
  	 *  Set zero to use the default :option:`CONFIG_BT_CREATE_CONN_TIMEOUT`
  	 *  timeout.
  	 *
  	 *  @note Unused in @ref bt_conn_create_auto_le
  	 */
  	uint16_t timeout;
  };
  
  /** @brief Initialize create connection parameters
   *
   *  @param _options  Create connection options.
   *  @param _interval Create connection scan interval (N * 0.625 ms).
   *  @param _window   Create connection scan window (N * 0.625 ms).
   */
  #define BT_CONN_LE_CREATE_PARAM_INIT(_options, _interval, _window) \
  { \
  	.options = (_options), \
  	.interval = (_interval), \
  	.window = (_window), \
  	.interval_coded = 0, \
  	.window_coded = 0, \
  	.timeout = 0, \
  }
  
  /** Helper to declare create connection parameters inline
   *
   *  @param _options  Create connection options.
   *  @param _interval Create connection scan interval (N * 0.625 ms).
   *  @param _window   Create connection scan window (N * 0.625 ms).
   */
  #define BT_CONN_LE_CREATE_PARAM(_options, _interval, _window) \
  	((struct bt_conn_le_create_param[]) { \
  		BT_CONN_LE_CREATE_PARAM_INIT(_options, _interval, _window) \
  	 })
  
  /** Default LE create connection parameters.
   *  Scan continuously by setting scan interval equal to scan window.
   */
  #define BT_CONN_LE_CREATE_CONN \
  	BT_CONN_LE_CREATE_PARAM(BT_CONN_LE_OPT_NONE, \
  				BT_GAP_SCAN_FAST_INTERVAL, \
  				BT_GAP_SCAN_FAST_INTERVAL)
  
  /** Default LE create connection using whitelist parameters.
   *  Scan window:   30 ms.
   *  Scan interval: 60 ms.
   */
  #define BT_CONN_LE_CREATE_CONN_AUTO \
  	BT_CONN_LE_CREATE_PARAM(BT_CONN_LE_OPT_NONE, \
  				BT_GAP_SCAN_FAST_INTERVAL, \
  				BT_GAP_SCAN_FAST_WINDOW)
  
  /** @brief Initiate an LE connection to a remote device.
   *
   *  Allows initiate new LE link to remote peer using its address.
   *
   *  The caller gets a new reference to the connection object which must be
   *  released with bt_conn_unref() once done using the object.
   *
   *  This uses the General Connection Establishment procedure.
   *
   *  @param[in]  peer         Remote address.
   *  @param[in]  create_param Create connection parameters.
   *  @param[in]  conn_param   Initial connection parameters.
   *  @param[out] conn         Valid connection object on success.
   *
   *  @return Zero on success or (negative) error code on failure.
   */
  int bt_conn_le_create(const bt_addr_le_t *peer,
  		      const struct bt_conn_le_create_param *create_param,
  		      const struct bt_le_conn_param *conn_param,
  		      struct bt_conn **conn);
  
  __deprecated static inline
  struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer,
  				  const struct bt_le_conn_param *conn_param)
  {
  	struct bt_conn *conn;
  	struct bt_conn_le_create_param param = BT_CONN_LE_CREATE_PARAM_INIT(
  						BT_CONN_LE_OPT_NONE,
  						BT_GAP_SCAN_FAST_INTERVAL,
  						BT_GAP_SCAN_FAST_INTERVAL);
  
  	if (bt_conn_le_create(peer, &param, conn_param,
  			      &conn)) {
  		return NULL;
  	}
  
  	return conn;
  }
  
  /** @brief Automatically connect to remote devices in whitelist.
   *
   *  This uses the Auto Connection Establishment procedure.
   *  The procedure will continue until a single connection is established or the
   *  procedure is stopped through @ref bt_conn_create_auto_stop.
   *  To establish connections to all devices in the whitelist the procedure
   *  should be started again in the connected callback after a new connection has
   *  been established.
   *
   *  @param create_param Create connection parameters
   *  @param conn_param   Initial connection parameters.
   *
   *  @return Zero on success or (negative) error code on failure.
   *  @return -ENOMEM No free connection object available.
   */
  int bt_conn_le_create_auto(const struct bt_conn_le_create_param *create_param,
  			   const struct bt_le_conn_param *conn_param);
  
  __deprecated static inline
  int bt_conn_create_auto_le(const struct bt_le_conn_param *conn_param)
  {
  	struct bt_conn_le_create_param param = BT_CONN_LE_CREATE_PARAM_INIT(
  						BT_CONN_LE_OPT_NONE,
  						BT_GAP_SCAN_FAST_INTERVAL,
  						BT_GAP_SCAN_FAST_WINDOW);
  
  	return bt_conn_le_create_auto(&param, conn_param);
  }
  
  /** @brief Stop automatic connect creation.
   *
   *  @return Zero on success or (negative) error code on failure.
   */
  int bt_conn_create_auto_stop(void);
  
  /** @brief Automatically connect to remote device if it's in range.
   *
   *  This function enables/disables automatic connection initiation.
   *  Every time the device loses the connection with peer, this connection
   *  will be re-established if connectable advertisement from peer is received.
   *
   *  @note Auto connect is disabled during explicit scanning.
   *
   *  @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(const 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 will either be BT_LE_ADV_DIRECT_IND, or
   *  BT_LE_ADV_DIRECT_IND_LOW_DUTY if the BT_LE_ADV_OPT_DIR_MODE_LOW_DUTY
   *  option was used as part of the advertising parameters.
   *
   *  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 canceled with bt_conn_disconnect().
   *
   *  The caller gets a new reference to the connection object which must be
   *  released with bt_conn_unref() once done using the object.
   *
   *  @param peer  Remote address.
   *  @param param Directed advertising parameters.
   *
   *  @return Valid connection object on success or NULL otherwise.
   */
  __deprecated static inline
  struct bt_conn *bt_conn_create_slave_le(const bt_addr_le_t *peer,
  					const struct bt_le_adv_param *param)
  {
  	struct bt_le_adv_param adv_param = *param;
  
  	adv_param.options |= (BT_LE_ADV_OPT_CONNECTABLE |
  			      BT_LE_ADV_OPT_ONE_TIME);
  	adv_param.peer = peer;
  
  	if (!bt_le_adv_start(&adv_param, NULL, 0, NULL, 0)) {
  		return NULL;
  	}
  
  	return bt_conn_lookup_addr_le(param->id, peer);
  }
  
  /** Security level. */
  typedef enum __packed {
  	/** Level 0: Only for BR/EDR special cases, like SDP */
  	BT_SECURITY_L0,
  	/** Level 1: No encryption and no authentication. */
  	BT_SECURITY_L1,
  	/** Level 2: Encryption and no authentication (no MITM). */
  	BT_SECURITY_L2,
  	/** Level 3: Encryption and authentication (MITM). */
  	BT_SECURITY_L3,
  	/** Level 4: Authenticated Secure Connections and 128-bit key. */
  	BT_SECURITY_L4,
  
  	BT_SECURITY_NONE   __deprecated = BT_SECURITY_L0,
  	BT_SECURITY_LOW    __deprecated = BT_SECURITY_L1,
  	BT_SECURITY_MEDIUM __deprecated = BT_SECURITY_L2,
  	BT_SECURITY_HIGH   __deprecated = BT_SECURITY_L3,
  	BT_SECURITY_FIPS   __deprecated = BT_SECURITY_L4,
  
  	/** Bit to force new pairing procedure, bit-wise OR with requested
  	 *  security level.
  	 */
  	BT_SECURITY_FORCE_PAIR = BIT(7),
  } 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 (e.g., input output
   *  capabilities), or if the maximum number of paired devices has been reached.
   *
   *  This function may return error if the pairing procedure has already been
   *  initiated by the local device or the peer device.
   *
   *  @note When :option:`CONFIG_BT_SMP_SC_ONLY` is enabled then the security
   *        level will always be level 4.
   *
   *  @note When :option:`CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY` is enabled then the
   *        security level will always be level 3.
   *
   *  @param conn Connection object.
   *  @param sec Requested security level.
   *
   *  @return 0 on success or negative error
   */
  int bt_conn_set_security(struct bt_conn *conn, bt_security_t sec);
  
  /** @brief Get security level for a connection.
   *
   *  @return Connection security level
   */
  bt_security_t bt_conn_get_security(struct bt_conn *conn);
  
  static inline int __deprecated bt_conn_security(struct bt_conn *conn,
  						bt_security_t sec)
  {
  	return bt_conn_set_security(conn, 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);
  
  enum bt_security_err {
  	/** Security procedure successful. */
  	BT_SECURITY_ERR_SUCCESS,
  
  	/** Authentication failed. */
  	BT_SECURITY_ERR_AUTH_FAIL,
  
  	/** PIN or encryption key is missing. */
  	BT_SECURITY_ERR_PIN_OR_KEY_MISSING,
  
  	/** OOB data is not available.  */
  	BT_SECURITY_ERR_OOB_NOT_AVAILABLE,
  
  	/** The requested security level could not be reached. */
  	BT_SECURITY_ERR_AUTH_REQUIREMENT,
  
  	/** Pairing is not supported */
  	BT_SECURITY_ERR_PAIR_NOT_SUPPORTED,
  
  	/** Pairing is not allowed. */
  	BT_SECURITY_ERR_PAIR_NOT_ALLOWED,
  
  	/** Invalid parameters. */
  	BT_SECURITY_ERR_INVALID_PARAM,
  
  	/** Pairing failed but the exact reason could not be specified. */
  	BT_SECURITY_ERR_UNSPECIFIED,
  };
  
  /** @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 permissible 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.
  	 *
  	 *  @p err can mean either of the following:
  	 *  - @ref BT_HCI_ERR_UNKNOWN_CONN_ID Creating the connection started by
  	 *    @ref bt_conn_create_le was canceled either by the user through
  	 *    @ref bt_conn_disconnect or by the timeout in the host through
  	 *    @ref bt_conn_le_create_param timeout parameter, which defaults to
  	 *    :option:`CONFIG_BT_CREATE_CONN_TIMEOUT` seconds.
  	 *  - @p BT_HCI_ERR_ADV_TIMEOUT High duty cycle directed connectable
  	 *    advertiser started by @ref bt_le_adv_start failed to be connected
  	 *    within the timeout.
  	 */
  	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.
  	 *
  	 *  When this callback is called the stack still has one reference to
  	 *  the connection object. If the application in this callback tries to
  	 *  start either a connectable advertiser or create a new connection
  	 *  this might fail because there are no free connection objects
  	 *  available.
  	 *  To avoid this issue it is recommended to either start connectable
  	 *  advertise or create a new connection using @ref k_work_submit or
  	 *  increase :option:`CONFIG_BT_MAX_CONN`.
  	 *
  	 *  @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_BT_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_BT_SMP */
  #if defined(CONFIG_BT_SMP) || defined(CONFIG_BT_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.
  	 *  @param err Security error. Zero for success, non-zero otherwise.
  	 */
  	void (*security_changed)(struct bt_conn *conn, bt_security_t level,
  				 enum bt_security_err err);
  #endif /* defined(CONFIG_BT_SMP) || defined(CONFIG_BT_BREDR) */
  
  #if defined(CONFIG_BT_REMOTE_INFO)
  	/** @brief Remote information procedures has completed.
  	 *
  	 *  This callback notifies the application that the remote information
  	 *  has been retrieved from the remote peer.
  	 *
  	 *  @param conn Connection object.
  	 *  @param remote_info Connection information of remote device.
  	 */
  	void (*remote_info_available)(struct bt_conn *conn,
  				      struct bt_conn_remote_info *remote_info);
  #endif /* defined(CONFIG_BT_REMOTE_INFO) */
  
  #if defined(CONFIG_BT_USER_PHY_UPDATE)
  	/** @brief The PHY of the connection has changed.
  	 *
  	 *  This callback notifies the application that the PHY of the
  	 *  connection has changed.
  	 *
  	 *  @param conn Connection object.
  	 *  @param info Connection LE PHY information.
  	 */
  	void (*le_phy_updated)(struct bt_conn *conn,
  			       struct bt_conn_le_phy_info *param);
  #endif /* defined(CONFIG_BT_USER_PHY_UPDATE) */
  
  #if defined(CONFIG_BT_USER_DATA_LEN_UPDATE)
  	/** @brief The data length parameters of the connection has changed.
  	 *
  	 *  This callback notifies the application that the maximum Link Layer
  	 *  payload length or transmission time has changed.
  	 *
  	 *  @param conn Connection object.
  	 *  @param info Connection data length information.
  	 */
  	void (*le_data_len_updated)(struct bt_conn *conn,
  				    struct bt_conn_le_data_len_info *info);
  #endif /* defined(CONFIG_BT_USER_PHY_UPDATE) */
  
  	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);
  
  /** @brief Enable/disable bonding.
   *
   *  Set/clear the Bonding flag in the Authentication Requirements of
   *  SMP Pairing Request/Response data.
   *  The initial value of this flag depends on BT_BONDABLE Kconfig setting.
   *  For the vast majority of applications calling this function shouldn't be
   *  needed.
   *
   *  @param enable Value allowing/disallowing to be bondable.
   */
  void bt_set_bondable(bool enable);
  
  /** @brief Allow/disallow remote OOB data to be used for pairing.
   *
   *  Set/clear the OOB data flag for SMP Pairing Request/Response data.
   *  The initial value of this flag depends on BT_OOB_DATA_PRESENT Kconfig
   *  setting.
   *
   *  @param enable Value allowing/disallowing remote OOB data.
   */
  void bt_set_oob_data_flag(bool enable);
  
  /** @brief Set OOB Temporary Key to be used for pairing
   *
   *  This function allows to set OOB data for the LE legacy pairing procedure.
   *  The function should only be called in response to the oob_data_request()
   *  callback provided that the legacy method is user pairing.
   *
   *  @param conn Connection object
   *  @param tk Pointer to 16 byte long TK array
   *
   *  @return Zero on success or -EINVAL if NULL
   */
  int bt_le_oob_set_legacy_tk(struct bt_conn *conn, const uint8_t *tk);
  
  /** @brief Set OOB data during LE Secure Connections (SC) pairing procedure
   *
   *  This function allows to set OOB data during the LE SC pairing procedure.
   *  The function should only be called in response to the oob_data_request()
   *  callback provided that LE SC method is used for pairing.
   *
   *  The user should submit OOB data according to the information received in the
   *  callback. This may yield three different configurations: with only local OOB
   *  data present, with only remote OOB data present or with both local and
   *  remote OOB data present.
   *
   *  @param conn Connection object
   *  @param oobd_local Local OOB data or NULL if not present
   *  @param oobd_remote Remote OOB data or NULL if not present
   *
   *  @return Zero on success or error code otherwise, positive in case of
   *          protocol error or negative (POSIX) in case of stack internal error.
   */
  int bt_le_oob_set_sc_data(struct bt_conn *conn,
  			  const struct bt_le_oob_sc_data *oobd_local,
  			  const struct bt_le_oob_sc_data *oobd_remote);
  
  /** @brief Get OOB data used for LE Secure Connections (SC) pairing procedure
   *
   *  This function allows to get OOB data during the LE SC pairing procedure that
   *  were set by the bt_le_oob_set_sc_data() API.
   *
   *  @note The OOB data will only be available as long as the connection object
   *  associated with it is valid.
   *
   *  @param conn Connection object
   *  @param oobd_local Local OOB data or NULL if not set
   *  @param oobd_remote Remote OOB data or NULL if not set
   *
   *  @return Zero on success or error code otherwise, positive in case of
   *          protocol error or negative (POSIX) in case of stack internal error.
   */
  int bt_le_oob_get_sc_data(struct bt_conn *conn,
  			  const struct bt_le_oob_sc_data **oobd_local,
  			  const struct bt_le_oob_sc_data **oobd_remote);
  
  /** @def BT_PASSKEY_INVALID
   *
   *  Special passkey value that can be used to disable a previously
   *  set fixed passkey.
   */
  #define BT_PASSKEY_INVALID 0xffffffff
  
  /** @brief Set a fixed passkey to be used for pairing.
   *
   *  This API is only available when the CONFIG_BT_FIXED_PASSKEY
   *  configuration option has been enabled.
   *
   *  Sets a fixed passkey to be used for pairing. If set, the
   *  pairing_confim() callback will be called for all incoming pairings.
   *
   *  @param passkey A valid passkey (0 - 999999) or BT_PASSKEY_INVALID
   *                 to disable a previously set fixed passkey.
   *
   *  @return 0 on success or a negative error code on failure.
   */
  int bt_passkey_set(unsigned int passkey);
  
  /** Info Structure for OOB pairing */
  struct bt_conn_oob_info {
  	/** Type of OOB pairing method */
  	enum {
  		/** LE legacy pairing */
  		BT_CONN_OOB_LE_LEGACY,
  
  		/** LE SC pairing */
  		BT_CONN_OOB_LE_SC,
  	} type;
  
  	union {
  		/** LE Secure Connections OOB pairing parameters */
  		struct {
  			/** OOB data configuration */
  			enum {
  				/** Local OOB data requested */
  				BT_CONN_OOB_LOCAL_ONLY,
  
  				/** Remote OOB data requested */
  				BT_CONN_OOB_REMOTE_ONLY,
  
  				/** Both local and remote OOB data requested */
  				BT_CONN_OOB_BOTH_PEERS,
  
  				/** No OOB data requested */
  				BT_CONN_OOB_NO_DATA,
  			} oob_config;
  		} lesc;
  	};
  };
  
  #if defined(CONFIG_BT_SMP_APP_PAIRING_ACCEPT)
  /** @brief Pairing request and pairing response info structure.
   *
   *  This structure is the same for both smp_pairing_req and smp_pairing_rsp
   *  and a subset of the packet data, except for the initial Code octet.
   *  It is documented in Core Spec. Vol. 3, Part H, 3.5.1 and 3.5.2.
   */
  struct bt_conn_pairing_feat {
  	/** IO Capability, Core Spec. Vol 3, Part H, 3.5.1, Table 3.4 */
  	uint8_t io_capability;
  
  	/** OOB data flag, Core Spec. Vol 3, Part H, 3.5.1, Table 3.5 */
  	uint8_t oob_data_flag;
  
  	/** AuthReq, Core Spec. Vol 3, Part H, 3.5.1, Fig. 3.3 */
  	uint8_t auth_req;
  
  	/** Maximum Encryption Key Size, Core Spec. Vol 3, Part H, 3.5.1 */
  	uint8_t max_enc_key_size;
  
  	/** Initiator Key Distribution/Generation, Core Spec. Vol 3, Part H,
  	 *  3.6.1, Fig. 3.11
  	 */
  	uint8_t init_key_dist;
  
  	/** Responder Key Distribution/Generation, Core Spec. Vol 3, Part H
  	 *  3.6.1, Fig. 3.11
  	 */
  	uint8_t resp_key_dist;
  };
  #endif /* CONFIG_BT_SMP_APP_PAIRING_ACCEPT */
  
  /** Authenticated pairing callback structure */
  struct bt_conn_auth_cb {
  #if defined(CONFIG_BT_SMP_APP_PAIRING_ACCEPT)
  	/** @brief Query to proceed incoming pairing or not.
  	 *
  	 *  On any incoming pairing req/rsp this callback will be called for
  	 *  the application to decide whether to allow for the pairing to
  	 *  continue.
  	 *
  	 *  The pairing info received from the peer is passed to assist
  	 *  making the decision.
  	 *
  	 *  As this callback is synchronous the application should return
  	 *  a response value immediately. Otherwise it may affect the
  	 *  timing during pairing. Hence, this information should not be
  	 *  conveyed to the user to take action.
  	 *
  	 *  The remaining callbacks are not affected by this, but do notice
  	 *  that other callbacks can be called during the pairing. Eg. if
  	 *  pairing_confirm is registered both will be called for Just-Works
  	 *  pairings.
  	 *
  	 *  This callback may be unregistered in which case pairing continues
  	 *  as if the Kconfig flag was not set.
  	 *
  	 *  This callback is not called for BR/EDR Secure Simple Pairing (SSP).
  	 *
  	 *  @param conn Connection where pairing is initiated.
  	 *  @param feat Pairing req/resp info.
  	 */
  	enum bt_security_err (*pairing_accept)(struct bt_conn *conn,
  			      const struct bt_conn_pairing_feat *const feat);
  #endif /* CONFIG_BT_SMP_APP_PAIRING_ACCEPT */
  
  	/** @brief Display a passkey to the user.
  	 *
  	 *  When called the application is expected to display the given
  	 *  passkey to the user, with the expectation that the passkey will
  	 *  then be entered on the peer device. The passkey will be in the
  	 *  range of 0 - 999999, and is expected to be padded with zeroes so
  	 *  that six digits are always shown. E.g. the value 37 should be
  	 *  shown as 000037.
  	 *
  	 *  This callback may be set to NULL, which means that the local
  	 *  device lacks the ability do display a passkey. If set
  	 *  to non-NULL the cancel callback must also be provided, since
  	 *  this is the only way the application can find out that it should
  	 *  stop displaying the passkey.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 *  @param passkey Passkey to show to the user.
  	 */
  	void (*passkey_display)(struct bt_conn *conn, unsigned int passkey);
  
  	/** @brief Request the user to enter a passkey.
  	 *
  	 *  When called the user is expected to enter a passkey. The passkey
  	 *  must be in the range of 0 - 999999, and should be expected to
  	 *  be zero-padded, as that's how the peer device will typically be
  	 *  showing it (e.g. 37 would be shown as 000037).
  	 *
  	 *  Once the user has entered the passkey its value should be given
  	 *  to the stack using the bt_conn_auth_passkey_entry() API.
  	 *
  	 *  This callback may be set to NULL, which means that the local
  	 *  device lacks the ability to enter a passkey. If set to non-NULL
  	 *  the cancel callback must also be provided, since this is the
  	 *  only way the application can find out that it should stop
  	 *  requesting the user to enter a passkey.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 */
  	void (*passkey_entry)(struct bt_conn *conn);
  
  	/** @brief Request the user to confirm a passkey.
  	 *
  	 *  When called the user is expected to confirm that the given
  	 *  passkey is also shown on the peer device.. The passkey will
  	 *  be in the range of 0 - 999999, and should be zero-padded to
  	 *  always be six digits (e.g. 37 would be shown as 000037).
  	 *
  	 *  Once the user has confirmed the passkey to match, the
  	 *  bt_conn_auth_passkey_confirm() API should be called. If the
  	 *  user concluded that the passkey doesn't match the
  	 *  bt_conn_auth_cancel() API should be called.
  	 *
  	 *  This callback may be set to NULL, which means that the local
  	 *  device lacks the ability to confirm a passkey. If set to non-NULL
  	 *  the cancel callback must also be provided, since this is the
  	 *  only way the application can find out that it should stop
  	 *  requesting the user to confirm a passkey.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 *  @param passkey Passkey to be confirmed.
  	 */
  	void (*passkey_confirm)(struct bt_conn *conn, unsigned int passkey);
  
  	/** @brief Request the user to provide Out of Band (OOB) data.
  	 *
  	 *  When called the user is expected to provide OOB data. The required
  	 *  data are indicated by the information structure.
  	 *
  	 *  For LE Secure Connections OOB pairing, the user should provide
  	 *  local OOB data, remote OOB data or both depending on their
  	 *  availability. Their value should be given to the stack using the
  	 *  bt_le_oob_set_sc_data() API.
  	 *
  	 *  This callback must be set to non-NULL in order to support OOB
  	 *  pairing.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 *  @param info OOB pairing information.
  	 */
  	void (*oob_data_request)(struct bt_conn *conn,
  				 struct bt_conn_oob_info *info);
  
  	/** @brief Cancel the ongoing user request.
  	 *
  	 *  This callback will be called to notify the application that it
  	 *  should cancel any previous user request (passkey display, entry
  	 *  or confirmation).
  	 *
  	 *  This may be set to NULL, but must always be provided whenever the
  	 *  passkey_display, passkey_entry passkey_confirm or pairing_confirm
  	 *  callback has been provided.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 */
  	void (*cancel)(struct bt_conn *conn);
  
  	/** @brief Request confirmation for an incoming pairing.
  	 *
  	 *  This callback will be called to confirm an incoming pairing
  	 *  request where none of the other user callbacks is applicable.
  	 *
  	 *  If the user decides to accept the pairing the
  	 *  bt_conn_auth_pairing_confirm() API should be called. If the
  	 *  user decides to reject the pairing the bt_conn_auth_cancel() API
  	 *  should be called.
  	 *
  	 *  This callback may be set to NULL, which means that the local
  	 *  device lacks the ability to confirm a pairing request. If set
  	 *  to non-NULL the cancel callback must also be provided, since
  	 *  this is the only way the application can find out that it should
  	 *  stop requesting the user to confirm a pairing request.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 */
  	void (*pairing_confirm)(struct bt_conn *conn);
  
  #if defined(CONFIG_BT_BREDR)
  	/** @brief Request the user to enter a passkey.
  	 *
  	 *  This callback will be called for a BR/EDR (Bluetooth Classic)
  	 *  connection where pairing is being performed. Once called the
  	 *  user is expected to enter a PIN code with a length between
  	 *  1 and 16 digits. If the @a highsec parameter is set to true
  	 *  the PIN code must be 16 digits long.
  	 *
  	 *  Once entered, the PIN code should be given to the stack using
  	 *  the bt_conn_auth_pincode_entry() API.
  	 *
  	 *  This callback may be set to NULL, however in that case pairing
  	 *  over BR/EDR will not be possible. If provided, the cancel
  	 *  callback must be provided as well.
  	 *
  	 *  @param conn Connection where pairing is currently active.
  	 *  @param highsec true if 16 digit PIN is required.
  	 */
  	void (*pincode_entry)(struct bt_conn *conn, bool highsec);
  #endif
  
  	/** @brief notify that pairing process was complete.
  	 *
  	 *  This callback notifies the application that the pairing process
  	 *  has been completed.
  	 *
  	 *  @param conn Connection object.
  	 *  @param bonded pairing is bonded or not.
  	 */
  	void (*pairing_complete)(struct bt_conn *conn, bool bonded);
  
  	/** @brief notify that pairing process has failed.
  	 *
  	 *  @param conn Connection object.
  	 *  @param reason Pairing failed reason
  	 */
  	void (*pairing_failed)(struct bt_conn *conn,
  			       enum bt_security_err reason);
  
  	/** @brief Notify that bond has been deleted.
  	 *
  	 *  This callback notifies the application that the bond information
  	 *  for the remote peer has been deleted
  	 *
  	 *  @param id   Which local identity had the bond.
  	 *  @param peer Remote address.
  	 */
  	void (*bond_deleted)(uint8_t id, const bt_addr_le_t *peer);
  };
  
  /** @brief Register authentication callbacks.
   *
   *  Register callbacks to handle authenticated pairing. Passing NULL
   *  unregisters a 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;
  };
  
  /** @brief Initialize BR/EDR connection parameters
   *
   *  @param role_switch True if role switch is allowed
   */
  #define BT_BR_CONN_PARAM_INIT(role_switch) \
  { \
  	.allow_role_switch = (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[]) { \
  		BT_BR_CONN_PARAM_INIT(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.
   *
   *  The caller gets a new reference to the connection object which must be
   *  released with bt_conn_unref() once done using the object.
   *
   *  @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.
   *
   *  The caller gets a new reference to the connection object which must be
   *  released with bt_conn_unref() once done using the object.
   *
   *  @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 /* ZEPHYR_INCLUDE_BLUETOOTH_CONN_H_ */
  