include/mbedtls/timing.h

/**
 * \file timing.h
 *
 * \brief Portable interface to the CPU cycle counter
 *
 *  Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifndef MBEDTLS_TIMING_H
#define MBEDTLS_TIMING_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if !defined(MBEDTLS_TIMING_ALT)
// Regular implementation
//

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          timer structure
 */
struct mbedtls_timing_hr_time
{
    unsigned char opaque[32];
};

/**
 * \brief          Context for mbedtls_timing_set/get_delay()
 */
typedef struct
{
    struct mbedtls_timing_hr_time   timer;
    uint32_t                        int_ms;
    uint32_t                        fin_ms;
} mbedtls_timing_delay_context;

extern volatile int mbedtls_timing_alarmed;

/**
 * \brief          Return the CPU cycle counter value
 *
 * \warning        This is only a best effort! Do not rely on this!
 *                 In particular, it is known to be unreliable on virtual
 *                 machines.
 */
unsigned long mbedtls_timing_hardclock( void );

/**
 * \brief          Return the elapsed time in milliseconds
 *
 * \param val      points to a timer structure
 * \param reset    if set to 1, the timer is restarted
 */
unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );

/**
 * \brief          Setup an alarm clock
 *
 * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
 *
 * \warning        Only one alarm at a time  is supported. In a threaded
 *                 context, this means one for the whole process, not one per
 *                 thread.
 */
void mbedtls_set_alarm( int seconds );

/**
 * \brief          Set a pair of delays to watch
 *                 (See \c mbedtls_timing_get_delay().)
 *
 * \param data     Pointer to timing data
 *                 Must point to a valid \c mbetls_timing_delay_context struct.
 * \param int_ms   First (intermediate) delay in milliseconds.
 * \param fin_ms   Second (final) delay in milliseconds.
 *                 Pass 0 to cancel the current delay.
 */
void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );

/**
 * \brief          Get the status of delays
 *                 (Memory helper: number of delays passed.)
 *
 * \param data     Pointer to timing data
 *                 Must point to a valid \c mbetls_timing_delay_context struct.
 *
 * \return         -1 if cancelled (fin_ms = 0)
 *                  0 if none of the delays are passed,
 *                  1 if only the intermediate delay is passed,
 *                  2 if the final delay is passed.
 */
int mbedtls_timing_get_delay( void *data );

#ifdef __cplusplus
}
#endif

#else  /* MBEDTLS_TIMING_ALT */
#include "timing_alt.h"
#endif /* MBEDTLS_TIMING_ALT */

#ifdef __cplusplus
extern "C" {
#endif

#if defined(MBEDTLS_SELF_TEST)
/**
 * \brief          Checkup routine
 *
 * \return         0 if successful, or 1 if a test failed
 */
int mbedtls_timing_self_test( int verbose );
#endif

#ifdef __cplusplus
}
#endif

#endif /* timing.h */