// Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2011 The Bitcoin developers
+// Copyright (c) 2009-2012 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
#include "headers.h"
// mapOrphanTransactions
//
-void static AddOrphanTx(const CDataStream& vMsg)
+void AddOrphanTx(const CDataStream& vMsg)
{
CTransaction tx;
CDataStream(vMsg) >> tx;
uint256 hash = tx.GetHash();
if (mapOrphanTransactions.count(hash))
return;
+
CDataStream* pvMsg = mapOrphanTransactions[hash] = new CDataStream(vMsg);
BOOST_FOREACH(const CTxIn& txin, tx.vin)
mapOrphanTransactionsByPrev.insert(make_pair(txin.prevout.hash, pvMsg));
mapOrphanTransactions.erase(hash);
}
+int LimitOrphanTxSize(int nMaxOrphans)
+{
+ int nEvicted = 0;
+ while (mapOrphanTransactions.size() > nMaxOrphans)
+ {
+ // Evict a random orphan:
+ std::vector<unsigned char> randbytes(32);
+ RAND_bytes(&randbytes[0], 32);
+ uint256 randomhash(randbytes);
+ map<uint256, CDataStream*>::iterator it = mapOrphanTransactions.lower_bound(randomhash);
+ if (it == mapOrphanTransactions.end())
+ it = mapOrphanTransactions.begin();
+ EraseOrphanTx(it->first);
+ ++nEvicted;
+ }
+ return nEvicted;
+}
// Check against previous transactions
map<uint256, CTxIndex> mapUnused;
int64 nFees = 0;
- if (!ConnectInputs(txdb, mapUnused, CDiskTxPos(1,1,1), pindexBest, nFees, false, false))
+ bool fInvalid = false;
+ if (!ConnectInputs(txdb, mapUnused, CDiskTxPos(1,1,1), pindexBest, nFees, false, false, 0, fInvalid))
{
- if (pfMissingInputs)
- *pfMissingInputs = true;
+ if (fInvalid)
+ return error("AcceptToMemoryPool() : FetchInputs found invalid tx %s", hash.ToString().substr(0,10).c_str());
return error("AcceptToMemoryPool() : ConnectInputs failed %s", hash.ToString().substr(0,10).c_str());
}
return nSubsidy + nFees;
}
-unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast)
+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)
+{
+ // Testnet has min-difficulty blocks
+ // after nTargetSpacing*2 time between blocks:
+ if (fTestNet && nTime > nTargetSpacing*2)
+ return bnProofOfWorkLimit.GetCompact();
+
+ 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 CBlock *pblock)
{
- const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks
- const int64 nTargetSpacing = 10 * 60;
- const int64 nInterval = nTargetTimespan / nTargetSpacing;
+ unsigned int nProofOfWorkLimit = bnProofOfWorkLimit.GetCompact();
// Genesis block
if (pindexLast == NULL)
- return bnProofOfWorkLimit.GetCompact();
+ return nProofOfWorkLimit;
// Only change once per interval
if ((pindexLast->nHeight+1) % nInterval != 0)
+ {
+ // Special rules for testnet after 15 Feb 2012:
+ if (fTestNet && pblock->nTime > 1329264000)
+ {
+ // If the new block's timestamp is more than 2* 10 minutes
+ // then allow mining of a min-difficulty block.
+ if (pblock->nTime - pindexLast->nTime > nTargetSpacing*2)
+ return nProofOfWorkLimit;
+ else
+ {
+ // Return the last non-special-min-difficulty-rules-block
+ const CBlockIndex* pindex = pindexLast;
+ while (pindex->pprev && pindex->nHeight % nInterval != 0 && pindex->nBits == nProofOfWorkLimit)
+ pindex = pindex->pprev;
+ return pindex->nBits;
+ }
+ }
+
return pindexLast->nBits;
+ }
// Go back by what we want to be 14 days worth of blocks
const CBlockIndex* pindexFirst = pindexLast;
printf("InvalidChainFound: WARNING: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade.\n");
}
+void CBlock::UpdateTime(const CBlockIndex* pindexPrev)
+{
+ nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+
+ // Updating time can change work required on testnet:
+ if (fTestNet)
+ nBits = GetNextWorkRequired(pindexPrev, this);
+}
+
}
// Remove transaction from index
- if (!txdb.EraseTxIndex(*this))
- return error("DisconnectInputs() : EraseTxPos failed");
+ // This can fail if a duplicate of this transaction was in a chain that got
+ // reorganized away. This is only possible if this transaction was completely
+ // spent, so erasing it would be a no-op anway.
+ txdb.EraseTxIndex(*this);
return true;
}
bool CTransaction::ConnectInputs(CTxDB& txdb, map<uint256, CTxIndex>& mapTestPool, CDiskTxPos posThisTx,
- CBlockIndex* pindexBlock, int64& nFees, bool fBlock, bool fMiner, int64 nMinFee)
+ CBlockIndex* pindexBlock, int64& nFees, bool fBlock, bool fMiner, int64 nMinFee,
+ bool& fInvalid)
{
+ // FetchInputs can return false either because we just haven't seen some inputs
+ // (in which case the transaction should be stored as an orphan)
+ // or because the transaction is malformed (in which case the transaction should
+ // be dropped). If tx is definitely invalid, fInvalid will be set to true.
+ fInvalid = false;
+
// Take over previous transactions' spent pointers
if (!IsCoinBase())
{
}
if (prevout.n >= txPrev.vout.size() || prevout.n >= txindex.vSpent.size())
+ {
+ // Revisit this if/when transaction replacement is implemented and allows
+ // adding inputs:
+ fInvalid = true;
return error("ConnectInputs() : %s prevout.n out of range %d %d %d prev tx %s\n%s", GetHash().ToString().substr(0,10).c_str(), prevout.n, txPrev.vout.size(), txindex.vSpent.size(), prevout.hash.ToString().substr(0,10).c_str(), txPrev.ToString().c_str());
+ }
// If prev is coinbase, check that it's matured
if (txPrev.IsCoinBase())
if (!CheckBlock())
return false;
+ // Do not allow blocks that contain transactions which 'overwrite' older transactions,
+ // unless those are already completely spent.
+ // If such overwrites are allowed, coinbases and transactions depending upon those
+ // can be duplicated to remove the ability to spend the first instance -- even after
+ // being sent to another address.
+ // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
+ // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
+ // already refuses previously-known transaction id's entirely.
+ // This rule applies to all blocks whose timestamp is after March 15, 2012, 0:00 UTC.
+ // On testnet it is enabled as of februari 20, 2012, 0:00 UTC.
+ if (pindex->nTime > 1331769600 || (fTestNet && pindex->nTime > 1329696000))
+ BOOST_FOREACH(CTransaction& tx, vtx)
+ {
+ CTxIndex txindexOld;
+ if (txdb.ReadTxIndex(tx.GetHash(), txindexOld))
+ BOOST_FOREACH(CDiskTxPos &pos, txindexOld.vSpent)
+ if (pos.IsNull())
+ return false;
+ }
+
//// issue here: it doesn't know the version
unsigned int nTxPos = pindex->nBlockPos + ::GetSerializeSize(CBlock(), SER_DISK) - 1 + GetSizeOfCompactSize(vtx.size());
CDiskTxPos posThisTx(pindex->nFile, pindex->nBlockPos, nTxPos);
nTxPos += ::GetSerializeSize(tx, SER_DISK);
- if (!tx.ConnectInputs(txdb, mapQueuedChanges, posThisTx, pindex, nFees, true, false))
+ bool fInvalid;
+ if (!tx.ConnectInputs(txdb, mapQueuedChanges, posThisTx, pindex, nFees, true, false, 0, fInvalid))
return false;
}
// Write queued txindex changes
int nHeight = pindexPrev->nHeight+1;
// Check proof of work
- if (nBits != GetNextWorkRequired(pindexPrev))
+ if (nBits != GetNextWorkRequired(pindexPrev, this))
return error("AcceptBlock() : incorrect proof of work");
// Check timestamp against prev
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)
+ {
+ 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)
+ {
+ 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))
{
}
// Ask the first connected node for block updates
- static int nAskedForBlocks;
+ static int nAskedForBlocks = 0;
if (!pfrom->fClient &&
(pfrom->nVersion < 32000 || pfrom->nVersion >= 32400) &&
(nAskedForBlocks < 1 || vNodes.size() <= 1))
{
printf("storing orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
AddOrphanTx(vMsg);
+
+ // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
+ int nEvicted = LimitOrphanTxSize(MAX_ORPHAN_TRANSACTIONS);
+ if (nEvicted > 0)
+ printf("mapOrphan overflow, removed %d tx\n", nEvicted);
}
}
// Transaction fee required depends on block size
bool fAllowFree = (nBlockSize + nTxSize < 4000 || CTransaction::AllowFree(dPriority));
- int64 nMinFee = tx.GetMinFee(nBlockSize, fAllowFree, true);
+ int64 nMinFee = tx.GetMinFee(nBlockSize, fAllowFree);
// Connecting shouldn't fail due to dependency on other memory pool transactions
// because we're already processing them in order of dependency
map<uint256, CTxIndex> mapTestPoolTmp(mapTestPool);
- if (!tx.ConnectInputs(txdb, mapTestPoolTmp, CDiskTxPos(1,1,1), pindexPrev, nFees, false, true, nMinFee))
+ bool fInvalid;
+ if (!tx.ConnectInputs(txdb, mapTestPoolTmp, CDiskTxPos(1,1,1), pindexPrev, nFees, false, true, nMinFee, fInvalid))
continue;
swap(mapTestPool, mapTestPoolTmp);
// Fill in header
pblock->hashPrevBlock = pindexPrev->GetBlockHash();
pblock->hashMerkleRoot = pblock->BuildMerkleTree();
- pblock->nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
- pblock->nBits = GetNextWorkRequired(pindexPrev);
+ pblock->UpdateTime(pindexPrev);
+ pblock->nBits = GetNextWorkRequired(pindexPrev, pblock.get());
pblock->nNonce = 0;
return pblock.release();
FormatHashBuffers(pblock.get(), pmidstate, pdata, phash1);
unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
+ unsigned int& nBlockBits = *(unsigned int*)(pdata + 64 + 8);
unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
break;
// Update nTime every few seconds
- pblock->nTime = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
+ pblock->UpdateTime(pindexPrev);
nBlockTime = ByteReverse(pblock->nTime);
+ if (fTestNet)
+ {
+ // Changing pblock->nTime can change work required on testnet:
+ nBlockBits = ByteReverse(pblock->nBits);
+ hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
+ }
}
}
}
git://git.novaco.in / novacoin.git / blobdiff