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replace ComputeMinWork with CheckMinWork

pull/1/head
jtimon 8 years ago
parent
commit
654871d436
  1. 7
      src/main.cpp
  2. 23
      src/pow.cpp
  3. 4
      src/pow.h
  4. 6
      src/test/DoS_tests.cpp

7
src/main.cpp

@ -2410,12 +2410,7 @@ bool AcceptBlockHeader(CBlockHeader& block, CValidationState& state, CBlockIndex @@ -2410,12 +2410,7 @@ bool AcceptBlockHeader(CBlockHeader& block, CValidationState& state, CBlockIndex
return state.DoS(100, error("CheckBlockHeader() : block with timestamp before last checkpoint"),
REJECT_CHECKPOINT, "time-too-old");
}
bool fOverflow = false;
uint256 bnNewBlock;
bnNewBlock.SetCompact(block.nBits, NULL, &fOverflow);
uint256 bnRequired;
bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime));
if (fOverflow || bnNewBlock > bnRequired)
if (!CheckMinWork(block.nBits, pcheckpoint->nBits, deltaTime))
{
return state.DoS(100, error("CheckBlockHeader() : block with too little proof-of-work"),
REJECT_INVALID, "bad-diffbits");

23
src/pow.cpp

@ -94,29 +94,36 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits) @@ -94,29 +94,36 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits)
}
//
// minimum amount of work that could possibly be required nTime after
// minimum work required was nBase
// true if nBits is greater than the minimum amount of work that could
// possibly be required deltaTime after minimum work required was nBase
//
unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime)
bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime)
{
bool fOverflow = false;
uint256 bnNewBlock;
bnNewBlock.SetCompact(nBits, NULL, &fOverflow);
if (fOverflow)
return false;
const uint256 &bnLimit = Params().ProofOfWorkLimit();
// Testnet has min-difficulty blocks
// after Params().TargetSpacing()*2 time between blocks:
if (Params().AllowMinDifficultyBlocks() && nTime > Params().TargetSpacing()*2)
return bnLimit.GetCompact();
if (Params().AllowMinDifficultyBlocks() && deltaTime > Params().TargetSpacing()*2)
return bnNewBlock <= bnLimit;
uint256 bnResult;
bnResult.SetCompact(nBase);
while (nTime > 0 && bnResult < bnLimit)
while (deltaTime > 0 && bnResult < bnLimit)
{
// Maximum 400% adjustment...
bnResult *= 4;
// ... in best-case exactly 4-times-normal target time
nTime -= Params().TargetTimespan()*4;
deltaTime -= Params().TargetTimespan()*4;
}
if (bnResult > bnLimit)
bnResult = bnLimit;
return bnResult.GetCompact();
return bnNewBlock <= bnResult;
}
void UpdateTime(CBlockHeader* pblock, const CBlockIndex* pindexPrev)

4
src/pow.h

@ -17,8 +17,8 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead @@ -17,8 +17,8 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
/** Check whether a block hash satisfies the proof-of-work requirement specified by nBits */
bool CheckProofOfWork(uint256 hash, unsigned int nBits);
/** Calculate the minimum amount of work a received block needs, without knowing its direct parent */
unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime);
/** Check the work is more than the minimum a received block needs, without knowing its direct parent */
bool CheckMinWork(unsigned int nBits, unsigned int nBase, int64_t deltaTime);
void UpdateTime(CBlockHeader* block, const CBlockIndex* pindexPrev);

6
src/test/DoS_tests.cpp

@ -106,11 +106,7 @@ static bool CheckNBits(unsigned int nbits1, int64_t time1, unsigned int nbits2, @@ -106,11 +106,7 @@ static bool CheckNBits(unsigned int nbits1, int64_t time1, unsigned int nbits2,
return CheckNBits(nbits2, time2, nbits1, time1);
int64_t deltaTime = time2-time1;
uint256 required;
required.SetCompact(ComputeMinWork(nbits1, deltaTime));
uint256 have;
have.SetCompact(nbits2);
return (have <= required);
return CheckMinWork(nbits2, nbits1, deltaTime);
}
BOOST_AUTO_TEST_CASE(DoS_checknbits)

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