88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/*
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* Copyright (c) 2016, The OpenThread Authors.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @file
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* This file implements a pseudo-random number generator.
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*
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* @warning
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* This implementation is not a true random number generator and does @em satisfy the Thread requirements.
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*/
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#include <openthread-types.h>
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#include <common/code_utils.hpp>
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#include <platform/random.h>
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#include "platform-posix.h"
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static uint32_t s_state = 1;
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void posixRandomInit(void)
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{
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s_state = NODE_ID;
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}
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uint32_t otPlatRandomGet(void)
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{
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uint32_t mlcg, p, q;
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uint64_t tmpstate;
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tmpstate = (uint64_t)33614 * (uint64_t)s_state;
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q = tmpstate & 0xffffffff;
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q = q >> 1;
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p = tmpstate >> 32;
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mlcg = p + q;
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if (mlcg & 0x80000000)
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{
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mlcg &= 0x7fffffff;
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mlcg++;
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}
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s_state = mlcg;
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return mlcg;
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}
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ThreadError otPlatSecureRandomGet(uint16_t aInputLength, uint8_t *aOutput, uint16_t *aOutputLength)
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{
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ThreadError error = kThreadError_None;
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VerifyOrExit(aOutput && aOutputLength, error = kThreadError_InvalidArgs);
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for (uint16_t length = 0; length < aInputLength; length++)
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{
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aOutput[length] = (uint8_t)otPlatRandomGet();
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}
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*aOutputLength = aInputLength;
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exit:
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return error;
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}
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