/** @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 {
	u16_t interval_min;
	u16_t interval_max;
	u16_t latency;
	u16_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 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(u8_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
 */
u8_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),
	/** All Connection Type */
	BT_CONN_TYPE_ALL = BT_CONN_TYPE_LE | BT_CONN_TYPE_BR | BT_CONN_TYPE_SCO,
};

/** 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;
	u16_t interval; /** Connection interval */
	u16_t latency; /** Connection slave latency */
	u16_t timeout; /** Connection supervision timeout */
};

/** 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,
};

/** @brief Connection Info Structure
 *
 *  @param type Connection Type
 *  @param role Connection Role
 *  @param id Which local identity the connection was created with
 *  @param le LE Connection specific Info
 *  @param br BR/EDR Connection specific Info
 */
struct bt_conn_info {
	u8_t type;

	u8_t role;

	u8_t id;

	union {
		struct bt_conn_le_info le;

		struct bt_conn_br_info br;
	};
};

/** LE Connection Remote Info Structure */
struct bt_conn_le_remote_info {

	/** Remote LE feature set (bitmask). */
	const u8_t *features;
};

/** BR/EDR Connection Remote Info structure */
struct bt_conn_br_remote_info {

	/** Remote feature set (pages of bitmasks). */
	const u8_t *features;

	/** Number of pages in the remote feature set. */
	u8_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 */
	u8_t  type;

	/** Remote Link Layer version */
	u8_t  version;

	/** Remote manufacturer identifier */
	u16_t manufacturer;

	/** Per-manufacturer unique revision */
	u16_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 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, u8_t reason);

enum {
	/** Convenience value when no options are specified. */
	BT_LE_CONN_OPT_NONE = 0,

	/** Enable LE Coded PHY.
	 *
	 *  Enable scanning on the LE Coded PHY.
	 *  Enable connection initiation on the LE Coded PHY.
	 */
	BT_LE_CONN_OPT_CODED = BIT(0),

	/** Enable LE 2M PHY.
	 *
	 *  Enable connection initiaton on the LE 2M PHY.
	 */
	BT_LE_CONN_OPT_2M = BIT(1),

	/** Disable LE 1M PHY.
	 *
	 *  Disable scanning on the LE 1M PHY.
	 *  Disable connection initiation on the LE 1M PHY.
	 *
	 *  @note Requires @ref BT_LE_CONN_OPT_CODED.
	 */
	BT_LE_CONN_OPT_NO_1M = BIT(2),
};

struct bt_conn_le_create_param {

	/** Bit-field of create connection options. */
	u32_t options;

	/** Scan interval (N * 0.625 ms) */
	u16_t interval;

	/** Scan window (N * 0.625 ms) */
	u16_t window;

	/** Scan interval LE Coded PHY (N * 0.625 MS)
	 *
	 *  Set zero to use same as LE 1M PHY scan interval
	 */
	u16_t interval_coded;

	/** Scan window LE Coded PHY (N * 0.625 MS)
	 *
	 *  Set zero to use same as LE 1M PHY scan window.
	 */
	u16_t window_coded;
};

/** 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[]) { { \
		.options = (_options), \
		.interval = (_interval), \
		.window = (_window), \
		.interval_coded = 0, \
		.window_coded = 0, \
	 } })

/** 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_LE_CONN_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_LE_CONN_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;

	if (bt_conn_le_create(peer, BT_CONN_LE_CREATE_CONN, 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)
{
	return bt_conn_le_create_auto(BT_CONN_LE_CREATE_CONN_AUTO, 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[in]  peer  Remote address.
 *  @param[in]  param Directed advertising parameters.
 *  @param[out] conn  Valid connection object on success.
 *
 *  @return Zero on success or (negative) error code on failure.
 */
int bt_conn_le_create_slave(const bt_addr_le_t *peer,
			    const struct bt_le_adv_param *param,
			    struct bt_conn **conn);

__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_conn *conn;

	if (bt_conn_le_create_slave(peer, param, &conn)) {
		return NULL;
	}

	return conn;
}

/** 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.
 *
 *  @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.
 */
u8_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
	 *    :option:`CONFIG_BT_CREATE_CONN_TIMEOUT`.
	 *  - @p BT_HCI_ERR_ADV_TIMEOUT Directed advertiser started by @ref
	 *    bt_conn_create_slave_le with high duty cycle timed out after 1.28
	 *    seconds.
	 */
	void (*connected)(struct bt_conn *conn, u8_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, u8_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, u16_t interval,
				 u16_t latency, u16_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.
	 */
	void (*remote_info_available)(struct bt_conn *conn,
				      struct bt_conn_remote_info *remote_info);
#endif /* defined(CONFIG_BT_REMOTE_INFO) */

	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);

/** 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);

/** 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 u8_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 */
	u8_t io_capability;

	/** OOB data flag, Core Spec. Vol 3, Part H, 3.5.1, Table 3.5 */
	u8_t oob_data_flag;

	/** AuthReq, Core Spec. Vol 3, Part H, 3.5.1, Fig. 3.3 */
	u8_t auth_req;

	/** Maximum Encryption Key Size, Core Spec. Vol 3, Part H, 3.5.1 */
	u8_t max_enc_key_size;

	/** Initiator Key Distribution/Generation, Core Spec. Vol 3, Part H,
	 *  3.6.1, Fig. 3.11
	 */
	u8_t init_key_dist;

	/** Responder Key Distribution/Generation, Core Spec. Vol 3, Part H
	 *  3.6.1, Fig. 3.11
	 */
	u8_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 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;
};

/** 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.
 *
 *  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_ */