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   1 /**
   2  * \file timing.h
   3  *
   4  * \brief Portable interface to timeouts and to the CPU cycle counter
   5  */
   6 /*
   7  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   8  *  SPDX-License-Identifier: GPL-2.0
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23  *
  24  *  This file is part of mbed TLS (https://tls.mbed.org)
  25  */
  26 #ifndef MBEDTLS_TIMING_H
  27 #define MBEDTLS_TIMING_H
  28
  29 #if !defined(MBEDTLS_CONFIG_FILE)
  30 #include "config.h"
  31 #else
  32 #include MBEDTLS_CONFIG_FILE
  33 #endif
  34
  35 #include <stdint.h>
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 #if !defined(MBEDTLS_TIMING_ALT)
  42 // Regular implementation
  43 //
  44
  45 /**
  46  * \brief          timer structure
  47  */
  48 struct mbedtls_timing_hr_time
  49 {
  50     unsigned char opaque[32];
  51 };
  52
  53 /**
  54  * \brief          Context for mbedtls_timing_set/get_delay()
  55  */
  56 typedef struct mbedtls_timing_delay_context
  57 {
  58     struct mbedtls_timing_hr_time   timer;
  59     uint32_t                        int_ms;
  60     uint32_t                        fin_ms;
  61 } mbedtls_timing_delay_context;
  62
  63 #else  /* MBEDTLS_TIMING_ALT */
  64 #include "timing_alt.h"
  65 #endif /* MBEDTLS_TIMING_ALT */
  66
  67 extern volatile int mbedtls_timing_alarmed;
  68
  69 /**
  70  * \brief          Return the CPU cycle counter value
  71  *
  72  * \warning        This is only a best effort! Do not rely on this!
  73  *                 In particular, it is known to be unreliable on virtual
  74  *                 machines.
  75  *
  76  * \note           This value starts at an unspecified origin and
  77  *                 may wrap around.
  78  */
  79 unsigned long mbedtls_timing_hardclock( void );
  80
  81 /**
  82  * \brief          Return the elapsed time in milliseconds
  83  *
  84  * \param val      points to a timer structure
  85  * \param reset    If 0, query the elapsed time. Otherwise (re)start the timer.
  86  *
  87  * \return         Elapsed time since the previous reset in ms. When
  88  *                 restarting, this is always 0.
  89  *
  90  * \note           To initialize a timer, call this function with reset=1.
  91  *
  92  *                 Determining the elapsed time and resetting the timer is not
  93  *                 atomic on all platforms, so after the sequence
  94  *                 `{ get_timer(1); ...; time1 = get_timer(1); ...; time2 =
  95  *                 get_timer(0) }` the value time1+time2 is only approximately
  96  *                 the delay since the first reset.
  97  */
  98 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );
  99
 100 /**
 101  * \brief          Setup an alarm clock
 102  *
 103  * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
 104  *                 (must be >=0)
 105  *
 106  * \warning        Only one alarm at a time  is supported. In a threaded
 107  *                 context, this means one for the whole process, not one per
 108  *                 thread.
 109  */
 110 void mbedtls_set_alarm( int seconds );
 111
 112 /**
 113  * \brief          Set a pair of delays to watch
 114  *                 (See \c mbedtls_timing_get_delay().)
 115  *
 116  * \param data     Pointer to timing data.
 117  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
 118  * \param int_ms   First (intermediate) delay in milliseconds.
 119  *                 The effect if int_ms > fin_ms is unspecified.
 120  * \param fin_ms   Second (final) delay in milliseconds.
 121  *                 Pass 0 to cancel the current delay.
 122  *
 123  * \note           To set a single delay, either use \c mbedtls_timing_set_timer
 124  *                 directly or use this function with int_ms == fin_ms.
 125  */
 126 void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );
 127
 128 /**
 129  * \brief          Get the status of delays
 130  *                 (Memory helper: number of delays passed.)
 131  *
 132  * \param data     Pointer to timing data
 133  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
 134  *
 135  * \return         -1 if cancelled (fin_ms = 0),
 136  *                  0 if none of the delays are passed,
 137  *                  1 if only the intermediate delay is passed,
 138  *                  2 if the final delay is passed.
 139  */
 140 int mbedtls_timing_get_delay( void *data );
 141
 142 #if defined(MBEDTLS_SELF_TEST)
 143 /**
 144  * \brief          Checkup routine
 145  *
 146  * \return         0 if successful, or 1 if a test failed
 147  */
 148 int mbedtls_timing_self_test( int verbose );
 149 #endif
 150
 151 #ifdef __cplusplus
 152 }
 153 #endif
 154
 155 #endif /* timing.h */