diff options
Diffstat (limited to 'src/main.cpp')
| -rw-r--r-- | src/main.cpp | 49 |
1 files changed, 46 insertions, 3 deletions
diff --git a/src/main.cpp b/src/main.cpp index 832a0f9240..a7871fcc16 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -659,11 +659,32 @@ int64 static GetBlockValue(int nHeight, int64 nFees) return nSubsidy + nFees; } +static const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks +static const int64 nTargetSpacing = 10 * 60; +static const int64 nInterval = nTargetTimespan / nTargetSpacing; + +// +// minimum amount of work that could possibly be required nTime after +// minimum work required was nBase +// +unsigned int ComputeMinWork(unsigned int nBase, int64 nTime) +{ + CBigNum bnResult; + bnResult.SetCompact(nBase); + while (nTime > 0 && bnResult < bnProofOfWorkLimit) + { + // Maximum 400% adjustment... + bnResult *= 4; + // ... in best-case exactly 4-times-normal target time + nTime -= nTargetTimespan*4; + } + if (bnResult > bnProofOfWorkLimit) + bnResult = bnProofOfWorkLimit; + return bnResult.GetCompact(); +} + unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast) { - const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks - const int64 nTargetSpacing = 10 * 60; - const int64 nInterval = nTargetTimespan / nTargetSpacing; // Genesis block if (pindexLast == NULL) @@ -1340,6 +1361,28 @@ bool ProcessBlock(CNode* pfrom, CBlock* pblock) if (!pblock->CheckBlock()) return error("ProcessBlock() : CheckBlock FAILED"); + CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(mapBlockIndex); + if (pcheckpoint && pblock->hashPrevBlock != hashBestChain) + { + // Extra checks to prevent "fill up memory by spamming with bogus blocks" + int64 deltaTime = pblock->GetBlockTime() - pcheckpoint->nTime; + if (deltaTime < 0) + { + pfrom->Misbehaving(100); + return error("ProcessBlock() : block with timestamp before last checkpoint"); + } + CBigNum bnNewBlock; + bnNewBlock.SetCompact(pblock->nBits); + CBigNum bnRequired; + bnRequired.SetCompact(ComputeMinWork(pcheckpoint->nBits, deltaTime)); + if (bnNewBlock > bnRequired) + { + pfrom->Misbehaving(100); + return error("ProcessBlock() : block with too little proof-of-work"); + } + } + + // If don't already have its previous block, shunt it off to holding area until we get it if (!mapBlockIndex.count(pblock->hashPrevBlock)) { |