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/*
* Copyright (c) 2016-2017, The OpenThread Authors.
* All rights reserved.
*
* 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 the copyright holder 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.
*/
/**
* @file
* This file implements a pseudo-random number generator.
*
*/
#include <assert.h>
#include <stdio.h>
#include <openthread/types.h>
#include <openthread/platform/random.h>
#include "utils/code_utils.h"
static uint32_t sState = 1;
void qorvoRandomInit(void)
{
#if __SANITIZE_ADDRESS__ == 0
otError error;
error = otPlatRandomGetTrue((uint8_t *)&sState, sizeof(sState));
assert(error == OT_ERROR_NONE);
#else // __SANITIZE_ADDRESS__
sState = (uint32_t)time(NULL);
#endif // __SANITIZE_ADDRESS__
}
uint32_t otPlatRandomGet(void)
{
uint32_t mlcg, p, q;
uint64_t tmpstate;
tmpstate = (uint64_t)33614 * (uint64_t)sState;
q = tmpstate & 0xffffffff;
q = q >> 1;
p = tmpstate >> 32;
mlcg = p + q;
if (mlcg & 0x80000000)
{
mlcg &= 0x7fffffff;
mlcg++;
}
sState = mlcg;
return mlcg;
}
otError otPlatRandomGetTrue(uint8_t *aOutput, uint16_t aOutputLength)
{
otError error = OT_ERROR_NONE;
#if __SANITIZE_ADDRESS__ == 0
FILE * file = NULL;
size_t readLength;
otEXPECT_ACTION(aOutput && aOutputLength, error = OT_ERROR_INVALID_ARGS);
file = fopen("/dev/urandom", "rb");
otEXPECT_ACTION(file != NULL, error = OT_ERROR_FAILED);
readLength = fread(aOutput, 1, aOutputLength, file);
otEXPECT_ACTION(readLength == aOutputLength, error = OT_ERROR_FAILED);
exit:
if (file != NULL)
{
fclose(file);
}
#else // __SANITIZE_ADDRESS__
/*
* THE IMPLEMENTATION BELOW IS NOT COMPLIANT WITH THE THREAD SPECIFICATION.
*
* Address Sanitizer triggers test failures when reading random
* values from /dev/urandom. The pseudo-random number generator
* implementation below is only used to enable continuous
* integration checks with Address Sanitizer enabled.
*/
otEXPECT_ACTION(aOutput && aOutputLength, error = OT_ERROR_INVALID_ARGS);
for (uint16_t length = 0; length < aOutputLength; length++)
{
aOutput[length] = (uint8_t)otPlatRandomGet();
}
exit:
#endif // __SANITIZE_ADDRESS__
return error;
}