From 6354935c485d116e1965567561c197ab3fbc0e11 Mon Sep 17 00:00:00 2001
From: Philip Kaufmann <phil.kaufmann@t-online.de>
Date: Thu, 26 Jun 2014 14:41:53 +0200
Subject: move rand functions from util to new random.h/.cpp

---
 src/random.cpp | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 140 insertions(+)
 create mode 100644 src/random.cpp

(limited to 'src/random.cpp')

diff --git a/src/random.cpp b/src/random.cpp
new file mode 100644
index 0000000000..4c7f150f75
--- /dev/null
+++ b/src/random.cpp
@@ -0,0 +1,140 @@
+// 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 <cstring> // for memset()
+
+#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);
+    memset(&nCounter, 0, 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;
+    }
+}
-- 
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