X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=src%2Fkernel.cpp;h=2484c3c15e2a8032a702606e03db6ad932cf7fac;hb=1ca032e9c756d7605db51cd6cfce418ab5113e81;hp=663e811c535da4a2fd6c86264183bace88abec05;hpb=84a4a7763f386934da90e2bd1e355b70023fa9ca;p=novacoin.git diff --git a/src/kernel.cpp b/src/kernel.cpp index 663e811..2484c3c 100644 --- a/src/kernel.cpp +++ b/src/kernel.cpp @@ -5,25 +5,62 @@ #include #include "kernel.h" -#include "db.h" +#include "txdb.h" using namespace std; extern int nStakeMaxAge; extern int nStakeTargetSpacing; -// Modifier interval: time to elapse before new modifier is computed -// Set to 6-hour for production network and 20-minute for test network -unsigned int nModifierInterval = MODIFIER_INTERVAL; +// Protocol switch time for fixed kernel modifier interval +unsigned int nModifierSwitchTime = 1413763200; // Mon, 20 Oct 2014 00:00:00 GMT +unsigned int nModifierTestSwitchTime = 1397520000; // Tue, 15 Apr 2014 00:00:00 GMT + +// Note: user must upgrade before the protocol switch deadline, otherwise it's required to +// re-download the blockchain. The timestamp of upgrade is recorded in the blockchain +// database. +unsigned int nModifierUpgradeTime = 0; + +typedef std::map MapModifierCheckpoints; // Hard checkpoints of stake modifiers to ensure they are deterministic static std::map mapStakeModifierCheckpoints = boost::assign::map_list_of - ( 0, 0x0e00670bu ) - ( 6000, 0xb7cbc5d3u ) - ( 12661, 0x5d84115du ) + ( 0, 0x0e00670bu ) + ( 9690, 0x97dcdafau ) + ( 12661, 0x5d84115du ) + ( 37092, 0xd230afccu ) + ( 44200, 0x05370164u ) + ( 65000, 0xc8e7be6au ) + ( 68600, 0x73a8cc4cu ) + ( 92161, 0xe21a911au ) + ( 98661, 0xd20c44d4u ) + ; + +// Hard checkpoints of stake modifiers to ensure they are deterministic (testNet) +static std::map mapStakeModifierCheckpointsTestNet = + boost::assign::map_list_of + ( 0, 0x0e00670bu ) ; +// Whether the given block is subject to new modifier protocol +bool IsFixedModifierInterval(unsigned int nTimeBlock) +{ + return (nTimeBlock >= (fTestNet? nModifierTestSwitchTime : nModifierSwitchTime)); +} + +// Get time weight +int64 GetWeight(int64 nIntervalBeginning, int64 nIntervalEnd) +{ + // Kernel hash weight starts from 0 at the 30-day min age + // this change increases active coins participating the hash and helps + // to secure the network when proof-of-stake difficulty is low + // + // Maximum TimeWeight is 90 days. + + return min(nIntervalEnd - nIntervalBeginning - nStakeMinAge, (int64)nStakeMaxAge); +} + // Get the last stake modifier and its generation time from a given block static bool GetLastStakeModifier(const CBlockIndex* pindex, uint64& nStakeModifier, int64& nModifierTime) { @@ -57,11 +94,8 @@ static int64 GetStakeModifierSelectionInterval() // select a block from the candidate blocks in vSortedByTimestamp, excluding // already selected blocks in vSelectedBlocks, and with timestamp up to // nSelectionIntervalStop. -static bool SelectBlockFromCandidates( - vector >& vSortedByTimestamp, - map& mapSelectedBlocks, - int64 nSelectionIntervalStop, uint64 nStakeModifierPrev, - const CBlockIndex** pindexSelected) +static bool SelectBlockFromCandidates(vector >& vSortedByTimestamp, map& mapSelectedBlocks, + int64 nSelectionIntervalStop, uint64 nStakeModifierPrev, const CBlockIndex** pindexSelected) { bool fSelected = false; uint256 hashBest = 0; @@ -116,15 +150,17 @@ static bool SelectBlockFromCandidates( // block. This is to make it difficult for an attacker to gain control of // additional bits in the stake modifier, even after generating a chain of // blocks. -bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64& nStakeModifier, bool& fGeneratedStakeModifier) +bool ComputeNextStakeModifier(const CBlockIndex* pindexCurrent, uint64& nStakeModifier, bool& fGeneratedStakeModifier) { nStakeModifier = 0; fGeneratedStakeModifier = false; + const CBlockIndex* pindexPrev = pindexCurrent->pprev; if (!pindexPrev) { fGeneratedStakeModifier = true; return true; // genesis block's modifier is 0 } + // First find current stake modifier and its generation block time // if it's not old enough, return the same stake modifier int64 nModifierTime = 0; @@ -132,10 +168,35 @@ bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64& nStakeModif return error("ComputeNextStakeModifier: unable to get last modifier"); if (fDebug) { - printf("ComputeNextStakeModifier: prev modifier=0x%016"PRI64x" time=%s\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str()); + printf("ComputeNextStakeModifier: prev modifier=0x%016"PRI64x" time=%s epoch=%u\n", nStakeModifier, DateTimeStrFormat(nModifierTime).c_str(), (unsigned int)nModifierTime); } if (nModifierTime / nModifierInterval >= pindexPrev->GetBlockTime() / nModifierInterval) + { + if (fDebug) + { + printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexPrev nHeight=%d nTime=%u\n", pindexPrev->nHeight, (unsigned int)pindexPrev->GetBlockTime()); + } return true; + } + if (nModifierTime / nModifierInterval >= pindexCurrent->GetBlockTime() / nModifierInterval) + { + // fixed interval protocol requires current block timestamp also be in a different modifier interval + if (IsFixedModifierInterval(pindexCurrent->nTime)) + { + if (fDebug) + { + printf("ComputeNextStakeModifier: no new interval keep current modifier: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime()); + } + return true; + } + else + { + if (fDebug) + { + printf("ComputeNextStakeModifier: old modifier at block %s not meeting fixed modifier interval: pindexCurrent nHeight=%d nTime=%u\n", pindexCurrent->GetBlockHash().ToString().c_str(), pindexCurrent->nHeight, (unsigned int)pindexCurrent->GetBlockTime()); + } + } + } // Sort candidate blocks by timestamp vector > vSortedByTimestamp; @@ -168,8 +229,7 @@ bool ComputeNextStakeModifier(const CBlockIndex* pindexPrev, uint64& nStakeModif // add the selected block from candidates to selected list mapSelectedBlocks.insert(make_pair(pindex->GetBlockHash(), pindex)); if (fDebug && GetBoolArg("-printstakemodifier")) - printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", - nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit()); + printf("ComputeNextStakeModifier: selected round %d stop=%s height=%d bit=%d\n", nRound, DateTimeStrFormat(nSelectionIntervalStop).c_str(), pindex->nHeight, pindex->GetStakeEntropyBit()); } // Print selection map for visualization of the selected blocks @@ -245,10 +305,8 @@ static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64& nStakeModifier // this ensures that the chance of getting a coinstake is proportional to the // amount of coin age one owns. // The reason this hash is chosen is the following: -// nStakeModifier: -// (v0.3) scrambles computation to make it very difficult to precompute -// future proof-of-stake at the time of the coin's confirmation -// (v0.2) nBits (deprecated): encodes all past block timestamps +// nStakeModifier: scrambles computation to make it very difficult to precompute +// future proof-of-stake at the time of the coin's confirmation // txPrev.block.nTime: prevent nodes from guessing a good timestamp to // generate transaction for future advantage // txPrev.offset: offset of txPrev inside block, to reduce the chance of @@ -261,7 +319,7 @@ static bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64& nStakeModifier // quantities so as to generate blocks faster, degrading the system back into // a proof-of-work situation. // -bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned int nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, uint256& hashProofOfStake, bool fPrintProofOfStake) +bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned int nTxPrevOffset, const CTransaction& txPrev, const COutPoint& prevout, unsigned int nTimeTx, uint256& hashProofOfStake, uint256& targetProofOfStake, bool fPrintProofOfStake) { if (nTimeTx < txPrev.nTime) // Transaction timestamp violation return error("CheckStakeKernelHash() : nTime violation"); @@ -274,11 +332,10 @@ bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned bnTargetPerCoinDay.SetCompact(nBits); int64 nValueIn = txPrev.vout[prevout.n].nValue; - // v0.3 protocol kernel hash weight starts from 0 at the 30-day min age - // this change increases active coins participating the hash and helps - // to secure the network when proof-of-stake difficulty is low - int64 nTimeWeight = min((int64)nTimeTx - txPrev.nTime, (int64)nStakeMaxAge) - nStakeMinAge; - CBigNum bnCoinDayWeight = CBigNum(nValueIn) * nTimeWeight / COIN / (24 * 60 * 60); + uint256 hashBlockFrom = blockFrom.GetHash(); + + CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64)txPrev.nTime, (int64)nTimeTx) / COIN / (24 * 60 * 60); + targetProofOfStake = (bnCoinDayWeight * bnTargetPerCoinDay).getuint256(); // Calculate hash CDataStream ss(SER_GETHASH, 0); @@ -286,7 +343,7 @@ bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned int nStakeModifierHeight = 0; int64 nStakeModifierTime = 0; - if (!GetKernelStakeModifier(blockFrom.GetHash(), nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake)) + if (!GetKernelStakeModifier(hashBlockFrom, nStakeModifier, nStakeModifierHeight, nStakeModifierTime, fPrintProofOfStake)) return false; ss << nStakeModifier; @@ -297,10 +354,9 @@ bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned printf("CheckStakeKernelHash() : using modifier 0x%016"PRI64x" at height=%d timestamp=%s for block from height=%d timestamp=%s\n", nStakeModifier, nStakeModifierHeight, DateTimeStrFormat(nStakeModifierTime).c_str(), - mapBlockIndex[blockFrom.GetHash()]->nHeight, + mapBlockIndex[hashBlockFrom]->nHeight, DateTimeStrFormat(blockFrom.GetBlockTime()).c_str()); - printf("CheckStakeKernelHash() : check protocol=%s modifier=0x%016"PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n", - "0.3", + printf("CheckStakeKernelHash() : check modifier=0x%016"PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n", nStakeModifier, nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx, hashProofOfStake.ToString().c_str()); @@ -314,10 +370,9 @@ bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned printf("CheckStakeKernelHash() : using modifier 0x%016"PRI64x" at height=%d timestamp=%s for block from height=%d timestamp=%s\n", nStakeModifier, nStakeModifierHeight, DateTimeStrFormat(nStakeModifierTime).c_str(), - mapBlockIndex[blockFrom.GetHash()]->nHeight, + mapBlockIndex[hashBlockFrom]->nHeight, DateTimeStrFormat(blockFrom.GetBlockTime()).c_str()); - printf("CheckStakeKernelHash() : pass protocol=%s modifier=0x%016"PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n", - "0.3", + printf("CheckStakeKernelHash() : pass modifier=0x%016"PRI64x" nTimeBlockFrom=%u nTxPrevOffset=%u nTimeTxPrev=%u nPrevout=%u nTimeTx=%u hashProof=%s\n", nStakeModifier, nTimeBlockFrom, nTxPrevOffset, txPrev.nTime, prevout.n, nTimeTx, hashProofOfStake.ToString().c_str()); @@ -326,7 +381,7 @@ bool CheckStakeKernelHash(unsigned int nBits, const CBlock& blockFrom, unsigned } // Check kernel hash target and coinstake signature -bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake) +bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hashProofOfStake, uint256& targetProofOfStake) { if (!tx.IsCoinStake()) return error("CheckProofOfStake() : called on non-coinstake %s", tx.GetHash().ToString().c_str()); @@ -340,7 +395,6 @@ bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hash CTxIndex txindex; if (!txPrev.ReadFromDisk(txdb, txin.prevout, txindex)) return tx.DoS(1, error("CheckProofOfStake() : INFO: read txPrev failed")); // previous transaction not in main chain, may occur during initial download - txdb.Close(); // Verify signature if (!VerifySignature(txPrev, tx, 0, true, 0)) @@ -351,23 +405,16 @@ bool CheckProofOfStake(const CTransaction& tx, unsigned int nBits, uint256& hash if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false)) return fDebug? error("CheckProofOfStake() : read block failed") : false; // unable to read block of previous transaction - if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, fDebug)) + if (!CheckStakeKernelHash(nBits, block, txindex.pos.nTxPos - txindex.pos.nBlockPos, txPrev, txin.prevout, tx.nTime, hashProofOfStake, targetProofOfStake, fDebug)) return tx.DoS(1, error("CheckProofOfStake() : INFO: check kernel failed on coinstake %s, hashProof=%s", tx.GetHash().ToString().c_str(), hashProofOfStake.ToString().c_str())); // may occur during initial download or if behind on block chain sync return true; } -// Check whether the coinstake timestamp meets protocol -bool CheckCoinStakeTimestamp(int64 nTimeBlock, int64 nTimeTx) -{ - // v0.3 protocol - return (nTimeBlock == nTimeTx); -} - // Get stake modifier checksum unsigned int GetStakeModifierChecksum(const CBlockIndex* pindex) { - assert (pindex->pprev || pindex->GetBlockHash() == hashGenesisBlock); + assert (pindex->pprev || pindex->GetBlockHash() == (!fTestNet ? hashGenesisBlock : hashGenesisBlockTestNet)); // Hash previous checksum with flags, hashProofOfStake and nStakeModifier CDataStream ss(SER_GETHASH, 0); if (pindex->pprev) @@ -381,8 +428,9 @@ unsigned int GetStakeModifierChecksum(const CBlockIndex* pindex) // Check stake modifier hard checkpoints bool CheckStakeModifierCheckpoints(int nHeight, unsigned int nStakeModifierChecksum) { - if (fTestNet) return true; // Testnet has no checkpoints - if (mapStakeModifierCheckpoints.count(nHeight)) - return nStakeModifierChecksum == mapStakeModifierCheckpoints[nHeight]; + MapModifierCheckpoints& checkpoints = (fTestNet ? mapStakeModifierCheckpointsTestNet : mapStakeModifierCheckpoints); + + if (checkpoints.count(nHeight)) + return nStakeModifierChecksum == checkpoints[nHeight]; return true; }