mbedtls/include/mbedtls/timing.h

161 lines
4.6 KiB
C

/**
* \file timing.h
*
* \brief Portable interface to timeouts and to the CPU cycle counter
*/
/*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#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.
*
* \note This value starts at an unspecified origin and
* may wrap around.
*/
unsigned long mbedtls_timing_hardclock( void );
/**
* \brief Return the elapsed time in milliseconds
*
* \param val points to a timer structure
* \param reset If 0, query the elapsed time. Otherwise (re)start the timer.
*
* \return Elapsed time since the previous reset in ms. When
* restarting, this is always 0.
*
* \note To initialize a timer, call this function with reset=1.
*
* Determining the elapsed time and resetting the timer is not
* atomic on all platforms, so after the sequence
* `{ get_timer(1); ...; time1 = get_timer(1); ...; time2 =
* get_timer(0) }` the value time1+time2 is only approximately
* the delay since the first reset.
*/
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
* (must be >=0)
*
* \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 mbedtls_timing_delay_context struct.
* \param int_ms First (intermediate) delay in milliseconds.
* The effect if int_ms > fin_ms is unspecified.
* \param fin_ms Second (final) delay in milliseconds.
* Pass 0 to cancel the current delay.
*
* \note To set a single delay, either use \c mbedtls_timing_set_timer
* directly or use this function with int_ms == fin_ms.
*/
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 mbedtls_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 */