From f718aedd9f244ee77a40f182bf6c6737730d975c Mon Sep 17 00:00:00 2001
From: Gavin Andresen <gavinandresen@gmail.com>
Date: Thu, 17 May 2012 12:13:14 -0400
Subject: [PATCH] Refactor: GetRandHash() method for util

---
 src/main.cpp           |  8 +++-----
 src/test/DoS_tests.cpp | 12 ++----------
 src/util.cpp           |  6 ++++++
 src/util.h             |  1 +
 4 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 427e435a90..d006510d1a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -201,9 +201,7 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
     while (mapOrphanTransactions.size() > nMaxOrphans)
     {
         // Evict a random orphan:
-        std::vector<unsigned char> randbytes(32);
-        RAND_bytes(&randbytes[0], 32);
-        uint256 randomhash(randbytes);
+        uint256 randomhash = GetRandHash();
         map<uint256, CDataStream*>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
         if (it == mapOrphanTransactions.end())
             it = mapOrphanTransactions.begin();
@@ -2354,7 +2352,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
                     // at a time so the setAddrKnowns of the chosen nodes prevent repeats
                     static uint256 hashSalt;
                     if (hashSalt == 0)
-                        RAND_bytes((unsigned char*)&hashSalt, sizeof(hashSalt));
+                        hashSalt = GetRandHash();
                     int64 hashAddr = addr.GetHash();
                     uint256 hashRand = hashSalt ^ (hashAddr<<32) ^ ((GetTime()+hashAddr)/(24*60*60));
                     hashRand = Hash(BEGIN(hashRand), END(hashRand));
@@ -2945,7 +2943,7 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
                     // 1/4 of tx invs blast to all immediately
                     static uint256 hashSalt;
                     if (hashSalt == 0)
-                        RAND_bytes((unsigned char*)&hashSalt, sizeof(hashSalt));
+                        hashSalt = GetRandHash();
                     uint256 hashRand = inv.hash ^ hashSalt;
                     hashRand = Hash(BEGIN(hashRand), END(hashRand));
                     bool fTrickleWait = ((hashRand & 3) != 0);
diff --git a/src/test/DoS_tests.cpp b/src/test/DoS_tests.cpp
index e5a8b4f68b..3a2b1d9d54 100644
--- a/src/test/DoS_tests.cpp
+++ b/src/test/DoS_tests.cpp
@@ -129,18 +129,10 @@ BOOST_AUTO_TEST_CASE(DoS_checknbits)
     
 }
 
-static uint256 RandomHash()
-{
-    std::vector<unsigned char> randbytes(32);
-    RAND_bytes(&randbytes[0], 32);
-    uint256 randomhash(randbytes);
-    return randomhash;
-}
-
 CTransaction RandomOrphan()
 {
     std::map<uint256, CDataStream*>::iterator it;
-    it = mapOrphanTransactions.lower_bound(RandomHash());
+    it = mapOrphanTransactions.lower_bound(GetRandHash());
     if (it == mapOrphanTransactions.end())
         it = mapOrphanTransactions.begin();
     const CDataStream* pvMsg = it->second;
@@ -162,7 +154,7 @@ BOOST_AUTO_TEST_CASE(DoS_mapOrphans)
         CTransaction tx;
         tx.vin.resize(1);
         tx.vin[0].prevout.n = 0;
-        tx.vin[0].prevout.hash = RandomHash();
+        tx.vin[0].prevout.hash = GetRandHash();
         tx.vin[0].scriptSig << OP_1;
         tx.vout.resize(1);
         tx.vout[0].nValue = 1*CENT;
diff --git a/src/util.cpp b/src/util.cpp
index 3569f22ecd..d8804c7291 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -174,6 +174,12 @@ int GetRandInt(int nMax)
     return GetRand(nMax);
 }
 
+uint256 GetRandHash()
+{
+    uint256 hash;
+    RAND_bytes((unsigned char*)&hash, sizeof(hash));
+    return hash;
+}
 
 
 
diff --git a/src/util.h b/src/util.h
index 5f8d0375da..01f09747c4 100644
--- a/src/util.h
+++ b/src/util.h
@@ -168,6 +168,7 @@ bool SetStartOnSystemStartup(bool fAutoStart);
 void ShrinkDebugFile();
 int GetRandInt(int nMax);
 uint64 GetRand(uint64 nMax);
+uint256 GetRandHash();
 int64 GetTime();
 void SetMockTime(int64 nMockTimeIn);
 int64 GetAdjustedTime();