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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "random.h"
#ifdef WIN32
#include "compat.h" // for Windows API
#endif
#include "util.h" // for LogPrint()
#ifndef WIN32
#include <sys/time.h>
#endif
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/rand.h>
static inline int64_t GetPerformanceCounter()
{
int64_t nCounter = 0;
#ifdef WIN32
QueryPerformanceCounter((LARGE_INTEGER*)&nCounter);
#else
timeval t;
gettimeofday(&t, NULL);
nCounter = (int64_t)(t.tv_sec * 1000000 + t.tv_usec);
#endif
return nCounter;
}
void RandAddSeed()
{
// Seed with CPU performance counter
int64_t nCounter = GetPerformanceCounter();
RAND_add(&nCounter, sizeof(nCounter), 1.5);
OPENSSL_cleanse((void*)&nCounter, sizeof(nCounter));
}
void RandAddSeedPerfmon()
{
RandAddSeed();
// This can take up to 2 seconds, so only do it every 10 minutes
static int64_t nLastPerfmon;
if (GetTime() < nLastPerfmon + 10 * 60)
return;
nLastPerfmon = GetTime();
#ifdef WIN32
// Don't need this on Linux, OpenSSL automatically uses /dev/urandom
// Seed with the entire set of perfmon data
std::vector <unsigned char> vData(250000,0);
long ret = 0;
unsigned long nSize = 0;
const size_t nMaxSize = 10000000; // Bail out at more than 10MB of performance data
while (true)
{
nSize = vData.size();
ret = RegQueryValueExA(HKEY_PERFORMANCE_DATA, "Global", NULL, NULL, begin_ptr(vData), &nSize);
if (ret != ERROR_MORE_DATA || vData.size() >= nMaxSize)
break;
vData.resize(std::max((vData.size()*3)/2, nMaxSize)); // Grow size of buffer exponentially
}
RegCloseKey(HKEY_PERFORMANCE_DATA);
if (ret == ERROR_SUCCESS)
{
RAND_add(begin_ptr(vData), nSize, nSize/100.0);
OPENSSL_cleanse(begin_ptr(vData), nSize);
LogPrint("rand", "%s: %lu bytes\n", __func__, nSize);
} else {
static bool warned = false; // Warn only once
if (!warned)
{
LogPrintf("%s: Warning: RegQueryValueExA(HKEY_PERFORMANCE_DATA) failed with code %i\n", __func__, ret);
warned = true;
}
}
#endif
}
bool GetRandBytes(unsigned char *buf, int num)
{
if (RAND_bytes(buf, num) != 1) {
LogPrintf("%s: OpenSSL RAND_bytes() failed with error: %s\n", __func__, ERR_error_string(ERR_get_error(), NULL));
return false;
}
return true;
}
uint64_t GetRand(uint64_t nMax)
{
if (nMax == 0)
return 0;
// The range of the random source must be a multiple of the modulus
// to give every possible output value an equal possibility
uint64_t nRange = (std::numeric_limits<uint64_t>::max() / nMax) * nMax;
uint64_t nRand = 0;
do {
GetRandBytes((unsigned char*)&nRand, sizeof(nRand));
} while (nRand >= nRange);
return (nRand % nMax);
}
int GetRandInt(int nMax)
{
return GetRand(nMax);
}
uint256 GetRandHash()
{
uint256 hash;
GetRandBytes((unsigned char*)&hash, sizeof(hash));
return hash;
}
uint32_t insecure_rand_Rz = 11;
uint32_t insecure_rand_Rw = 11;
void seed_insecure_rand(bool fDeterministic)
{
// The seed values have some unlikely fixed points which we avoid.
if(fDeterministic)
{
insecure_rand_Rz = insecure_rand_Rw = 11;
} else {
uint32_t tmp;
do {
GetRandBytes((unsigned char*)&tmp, 4);
} while(tmp == 0 || tmp == 0x9068ffffU);
insecure_rand_Rz = tmp;
do {
GetRandBytes((unsigned char*)&tmp, 4);
} while(tmp == 0 || tmp == 0x464fffffU);
insecure_rand_Rw = tmp;
}
}