| /* |
| * Copyright (c) 2019, 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 provides an implementation of OpenThread random number generation manager class. |
| */ |
| |
| #include "random.hpp" |
| |
| #include <openthread/platform/entropy.h> |
| |
| #include "common/code_utils.hpp" |
| #include "common/debug.hpp" |
| |
| namespace ot { |
| namespace Random { |
| |
| uint16_t Manager::sInitCount = 0; |
| Manager::NonCryptoPrng Manager::sPrng; |
| |
| Manager::Manager(void) |
| { |
| uint32_t seed; |
| |
| OT_ASSERT(sInitCount < 0xffff); |
| |
| VerifyOrExit(sInitCount == 0); |
| |
| #if !OPENTHREAD_RADIO |
| otPlatCryptoRandomInit(); |
| SuccessOrAssert(Random::Crypto::Fill(seed)); |
| #else |
| SuccessOrAssert(otPlatEntropyGet(reinterpret_cast<uint8_t *>(&seed), sizeof(seed))); |
| #endif |
| |
| sPrng.Init(seed); |
| |
| exit: |
| sInitCount++; |
| } |
| |
| Manager::~Manager(void) |
| { |
| OT_ASSERT(sInitCount > 0); |
| |
| sInitCount--; |
| VerifyOrExit(sInitCount == 0); |
| |
| #if !OPENTHREAD_RADIO |
| otPlatCryptoRandomDeinit(); |
| #endif |
| |
| exit: |
| return; |
| } |
| |
| uint32_t Manager::NonCryptoGetUint32(void) |
| { |
| OT_ASSERT(sInitCount > 0); |
| |
| return sPrng.GetNext(); |
| } |
| |
| //------------------------------------------------------------------- |
| // NonCryptoPrng |
| |
| void Manager::NonCryptoPrng::Init(uint32_t aSeed) |
| { |
| // The PRNG has a cycle of length 1 for the below two initial |
| // seeds. For all other seed values the cycle is ~2^31 long. |
| |
| if ((aSeed == 0) || (aSeed == 0x7fffffff)) |
| { |
| aSeed = 0x1; |
| } |
| |
| mState = aSeed; |
| } |
| |
| uint32_t Manager::NonCryptoPrng::GetNext(void) |
| { |
| uint32_t mlcg, p, q; |
| uint64_t tmpstate; |
| |
| tmpstate = static_cast<uint64_t>(33614) * static_cast<uint64_t>(mState); |
| q = tmpstate & 0xffffffff; |
| q = q >> 1; |
| p = tmpstate >> 32; |
| mlcg = p + q; |
| |
| if (mlcg & 0x80000000) |
| { |
| mlcg &= 0x7fffffff; |
| mlcg++; |
| } |
| |
| mState = mlcg; |
| |
| return mlcg; |
| } |
| |
| //------------------------------------------------------------------- |
| |
| namespace NonCrypto { |
| |
| uint8_t GetUint8InRange(uint8_t aMin, uint8_t aMax) |
| { |
| OT_ASSERT(aMax > aMin); |
| |
| return (aMin + (GetUint8() % (aMax - aMin))); |
| } |
| |
| uint16_t GetUint16InRange(uint16_t aMin, uint16_t aMax) |
| { |
| OT_ASSERT(aMax > aMin); |
| return (aMin + (GetUint16() % (aMax - aMin))); |
| } |
| |
| uint32_t GetUint32InRange(uint32_t aMin, uint32_t aMax) |
| { |
| OT_ASSERT(aMax > aMin); |
| return (aMin + (GetUint32() % (aMax - aMin))); |
| } |
| |
| void FillBuffer(uint8_t *aBuffer, uint16_t aSize) |
| { |
| while (aSize-- != 0) |
| { |
| *aBuffer++ = GetUint8(); |
| } |
| } |
| |
| uint32_t AddJitter(uint32_t aValue, uint16_t aJitter) |
| { |
| aJitter = (aJitter <= aValue) ? aJitter : static_cast<uint16_t>(aValue); |
| |
| return aValue + GetUint32InRange(0, 2 * aJitter + 1) - aJitter; |
| } |
| |
| } // namespace NonCrypto |
| } // namespace Random |
| } // namespace ot |