zephyr/include/bluetooth/bluetooth.h

/** @file
 *  @brief Bluetooth subsystem core APIs.
 */

/*
 * Copyright (c) 2015 Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1) Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2) Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3) Neither the name of Intel Corporation nor the names of its contributors
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef __BT_BLUETOOTH_H
#define __BT_BLUETOOTH_H

#include <stdio.h>
#include <string.h>

#include <bluetooth/buf.h>
#include <bluetooth/conn.h>
#include <bluetooth/hci.h>

/** @brief Initialize the Bluetooth Subsystem.
 *
 *  Initialize Bluetooth. Must be the called before anything else.
 *  Caller shall be either task or a fiber.
 *
 *  @return Zero on success or (negative) error code otherwise.
 */
int bt_init(void);

/* Advertising API */

struct bt_eir {
	uint8_t len;
	uint8_t type;
	uint8_t data[29];
} __packed;

/** @brief Define a type allowing user to implement a function that can
 *  be used to get back active LE scan results.
 *
 *  A function of this type will be called back when user application
 *  triggers active LE scan. The caller will populate all needed
 *  parameters based on data coming from scan result.
 *  Such function can be set by user when LE active scan API is used.
 *
 *  @param addr Advertiser LE address and type.
 *  @param rssi Strength of advertiser signal.
 *  @param adv_type Type of advertising response from advertiser.
 *  @param adv_data Address of buffer containig advertiser data.
 *  @param len Length of advertiser data contained in buffer.
 */
typedef void bt_le_scan_cb_t(const bt_addr_le_t *addr, int8_t rssi,
		             uint8_t adv_type, const uint8_t *adv_data,
		             uint8_t len);

/** @brief Start advertising
 *
 *  Set advertisement data, scan response data, advertisement parameters
 *  and start advertising.
 *
 *  @param type Advertising type.
 *  @param ad Data to be used in advertisement packets.
 *  @param sd Data to be used in scan response packets.
 *
 *  @return Zero on success or (negative) error code otherwise.
 */
int bt_start_advertising(uint8_t type, const struct bt_eir *ad,
			 const struct bt_eir *sd);

/** @brief Stop advertising
 *
 *  Stops ongoing advertising.
 *
 *  @return Zero on success or (negative) error code otherwise.
 */
int bt_stop_advertising(void);

/** @brief Start (LE) scanning
 *
 *  Start LE scanning with and provide results through the specified
 *  callback.
 *
 *  @param filter_dups Enable duplicate filtering (or not).
 *  @param cb Callback to notify scan results.
 *
 *  @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_start_scanning(uint8_t filter_dups, bt_le_scan_cb_t cb);

/** @brief Stop (LE) scanning.
 *
 *  Stops ongoing LE scanning.
 *
 *  @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_stop_scanning(void);

/** @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.
 *
 *  @return Valid connection object on success or NULL otherwise.
 */
struct bt_conn *bt_connect_le(const bt_addr_le_t *peer);

/** @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_disconnect(struct bt_conn *conn, uint8_t reason);

/** Security level. */
typedef enum {
	BT_SECURITY_LOW,    /** No encryption and no authentication. */
	BT_SECURITY_MEDIUM, /** encryption and no authentication (no MITM). */
	BT_SECURITY_HIGH,   /** encryption and authentication (MITM). */
	BT_SECURITY_FIPS,   /** Authenticated LE Secure Connections and
			     *  encryption.
			     */
} 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_security(struct bt_conn *conn, bt_security_t sec);

/** @def BT_ADDR_STR_LEN
 *
 *  @brief Recommended length of user string buffer for Bluetooth address
 *
 *  @details The recommended length guarantee the output of address
 *  conversion will not lose valuable information about address being
 *  processed.
 */
#define BT_ADDR_STR_LEN 18

/** @def BT_ADDR_LE_STR_LEN
 *
 *  @brief Recommended length of user string buffer for Bluetooth LE address
 *
 *  @details The recommended length guarantee the output of address
 *  conversion will not lose valuable information about address being
 *  processed.
 */
#define BT_ADDR_LE_STR_LEN 27

/** @brief Converts binary Bluetooth address to string.
 *
 *  @param addr Address of buffer containing binary Bluetooth address.
 *  @param str Address of user buffer with enough room to store formatted
 *  string containing binary address.
 *  @param len Length of data to be copied to user string buffer. Refer to
 *  BT_ADDR_STR_LEN about recommended value.
 *
 *  @return Number of successfully formatted bytes from binary address.
 */
static inline int bt_addr_to_str(const bt_addr_t *addr, char *str, size_t len)
{
	return snprintf(str, len, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
			addr->val[5], addr->val[4], addr->val[3],
			addr->val[2], addr->val[1], addr->val[0]);
}

/** @brief Converts binary LE Bluetooth address to string.
 *
 *  @param addr Address of buffer containing binary LE Bluetooth address.
 *  @param user_buf Address of user buffer with enough room to store
 *  formatted string containing binary LE address.
 *  @param len Length of data to be copied to user string buffer. Refer to
 *  BT_ADDR_LE_STR_LEN about recommended value.
 *
 *  @return Number of successfully formatted bytes from binary address.
 */
static inline int bt_addr_le_to_str(const bt_addr_le_t *addr, char *str,
				    size_t len)
{
	char type[7];

	switch (addr->type) {
	case BT_ADDR_LE_PUBLIC:
		strcpy(type, "public");
		break;
	case BT_ADDR_LE_RANDOM:
		strcpy(type, "random");
		break;
	default:
		sprintf(type, "0x%02x", addr->type);
		break;
	}

	return snprintf(str, len, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X (%s)",
			addr->val[5], addr->val[4], addr->val[3],
			addr->val[2], addr->val[1], addr->val[0], type);
}
#endif /* __BT_BLUETOOTH_H */