File timing.h

Portable interface to timeouts and to the CPU cycle counter.

Functions

unsigned long mbedtls_timing_hardclock(void)

Return the CPU cycle counter value.

Note

This value starts at an unspecified origin and may wrap around.

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_get_timer(struct mbedtls_timing_hr_time *val, int reset)

Return the elapsed time in milliseconds.

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.

Parameters

  • val – points to a timer structure

  • reset – If 0, query the elapsed time. Otherwise (re)start the timer.

Returns

Elapsed time since the previous reset in ms. When restarting, this is always 0.

void mbedtls_set_alarm(int seconds)

Setup an alarm clock.

Warning

Only one alarm at a time is supported. In a threaded context, this means one for the whole process, not one per thread.

Parameters

seconds – delay before the “mbedtls_timing_alarmed” flag is set (must be >=0)

void mbedtls_timing_set_delay(void *data, uint32_t int_ms, uint32_t fin_ms)

Set a pair of delays to watch (See mbedtls_timing_get_delay().)

Note

To set a single delay, either use mbedtls_timing_set_timer directly or use this function with int_ms == fin_ms.

Parameters

  • data – Pointer to timing data. Must point to a valid mbedtls_timing_delay_context struct.

  • int_ms – First (intermediate) delay in milliseconds. The effect if int_ms > fin_ms is unspecified.

  • fin_ms – Second (final) delay in milliseconds. Pass 0 to cancel the current delay.

int mbedtls_timing_get_delay(void *data)

Get the status of delays (Memory helper: number of delays passed.)

Parameters

data – Pointer to timing data Must point to a valid mbedtls_timing_delay_context struct.

Returns

-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_self_test(int verbose)

Checkup routine.

Returns

0 if successful, or 1 if a test failed

Variables

int mbedtls_timing_alarmed