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Add LockPoints

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Obtain LockPoints to store in CTxMemPoolEntry and during a reorg, evaluate whether they are still valid and if not, recalculate them.
This commit is contained in:
Alex Morcos 2015-12-04 15:01:22 -05:00
parent 8b70a64d62
commit 982670c333
6 changed files with 131 additions and 26 deletions
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89
src/main.cpp
View file

@ -794,7 +794,25 @@ bool SequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeig
return EvaluateSequenceLocks(block, CalculateSequenceLocks(tx, flags, prevHeights, block));
}
bool CheckSequenceLocks(const CTransaction &tx, int flags)
bool TestLockPointValidity(const LockPoints* lp)
{
AssertLockHeld(cs_main);
assert(lp);
// If there are relative lock times then the maxInputBlock will be set
// If there are no relative lock times, the LockPoints don't depend on the chain
if (lp->maxInputBlock) {
// Check whether chainActive is an extension of the block at which the LockPoints
// calculation was valid. If not LockPoints are no longer valid
if (!chainActive.Contains(lp->maxInputBlock)) {
return false;
}
}
// LockPoints still valid
return true;
}
bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool useExistingLockPoints)
{
AssertLockHeld(cs_main);
AssertLockHeld(mempool.cs);
@ -810,25 +828,57 @@ bool CheckSequenceLocks(const CTransaction &tx, int flags)
// *next* block, we need to use one more than chainActive.Height()
index.nHeight = tip->nHeight + 1;
// pcoinsTip contains the UTXO set for chainActive.Tip()
CCoinsViewMemPool viewMemPool(pcoinsTip, mempool);
std::vector<int> prevheights;
prevheights.resize(tx.vin.size());
for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
const CTxIn& txin = tx.vin[txinIndex];
CCoins coins;
if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
return error("%s: Missing input", __func__);
std::pair<int, int64_t> lockPair;
if (useExistingLockPoints) {
assert(lp);
lockPair.first = lp->height;
lockPair.second = lp->time;
}
else {
// pcoinsTip contains the UTXO set for chainActive.Tip()
CCoinsViewMemPool viewMemPool(pcoinsTip, mempool);
std::vector<int> prevheights;
prevheights.resize(tx.vin.size());
for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
const CTxIn& txin = tx.vin[txinIndex];
CCoins coins;
if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
return error("%s: Missing input", __func__);
}
if (coins.nHeight == MEMPOOL_HEIGHT) {
// Assume all mempool transaction confirm in the next block
prevheights[txinIndex] = tip->nHeight + 1;
} else {
prevheights[txinIndex] = coins.nHeight;
}
}
if (coins.nHeight == MEMPOOL_HEIGHT) {
// Assume all mempool transaction confirm in the next block
prevheights[txinIndex] = tip->nHeight + 1;
} else {
prevheights[txinIndex] = coins.nHeight;
lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
if (lp) {
lp->height = lockPair.first;
lp->time = lockPair.second;
// Also store the hash of the block with the highest height of
// all the blocks which have sequence locked prevouts.
// This hash needs to still be on the chain
// for these LockPoint calculations to be valid
// Note: It is impossible to correctly calculate a maxInputBlock
// if any of the sequence locked inputs depend on unconfirmed txs,
// except in the special case where the relative lock time/height
// is 0, which is equivalent to no sequence lock. Since we assume
// input height of tip+1 for mempool txs and test the resulting
// lockPair from CalculateSequenceLocks against tip+1. We know
// EvaluateSequenceLocks will fail if there was a non-zero sequence
// lock on a mempool input, so we can use the return value of
// CheckSequenceLocks to indicate the LockPoints validity
int maxInputHeight = 0;
BOOST_FOREACH(int height, prevheights) {
// Can ignore mempool inputs since we'll fail if they had non-zero locks
if (height != tip->nHeight+1) {
maxInputHeight = std::max(maxInputHeight, height);
}
}
lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
}
}
std::pair<int, int64_t> lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
return EvaluateSequenceLocks(index, lockPair);
}
@ -1017,6 +1067,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
CCoinsViewCache view(&dummy);
CAmount nValueIn = 0;
LockPoints lp;
{
LOCK(pool.cs);
CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
@ -1060,7 +1111,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
// be mined yet.
// Must keep pool.cs for this unless we change CheckSequenceLocks to take a
// CoinsViewCache instead of create its own
if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS))
if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");
}
@ -1092,7 +1143,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
}
}
CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps);
CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps, lp);
unsigned int nSize = entry.GetTxSize();
// Check that the transaction doesn't have an excessive number of

12
src/main.h
View file

@ -39,6 +39,7 @@ class CValidationInterface;
class CValidationState;
struct CNodeStateStats;
struct LockPoints;
/** Default for accepting alerts from the P2P network. */
static const bool DEFAULT_ALERTS = true;
@ -368,6 +369,11 @@ bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime);
*/
bool CheckFinalTx(const CTransaction &tx, int flags = -1);
/**
* Test whether the LockPoints height and time are still valid on the current chain
*/
bool TestLockPointValidity(const LockPoints* lp);
/**
* Check if transaction is final per BIP 68 sequence numbers and can be included in a block.
* Consensus critical. Takes as input a list of heights at which tx's inputs (in order) confirmed.
@ -378,10 +384,14 @@ bool SequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeig
* Check if transaction will be BIP 68 final in the next block to be created.
*
* Simulates calling SequenceLocks() with data from the tip of the current active chain.
* Optionally stores in LockPoints the resulting height and time calculated and the hash
* of the block needed for calculation or skips the calculation and uses the LockPoints
* passed in for evaluation.
* The LockPoints should not be considered valid if CheckSequenceLocks returns false.
*
* See consensus/consensus.h for flag definitions.
*/
bool CheckSequenceLocks(const CTransaction &tx, int flags);
bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp = NULL, bool useExistingLockPoints = false);
/**
* Closure representing one script verification

2
src/test/test_bitcoin.cpp
View file

@ -151,7 +151,7 @@ CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(CMutableTransaction &tx, CTxMemPo
CAmount inChainValue = hasNoDependencies ? txn.GetValueOut() : 0;
return CTxMemPoolEntry(txn, nFee, nTime, dPriority, nHeight,
hasNoDependencies, inChainValue, spendsCoinbase, sigOpCount);
hasNoDependencies, inChainValue, spendsCoinbase, sigOpCount, lp);
}
void Shutdown(void* parg)

4
src/test/test_bitcoin.h
View file

@ -9,6 +9,7 @@
#include "key.h"
#include "pubkey.h"
#include "txdb.h"
#include "txmempool.h"
#include <boost/filesystem.hpp>
#include <boost/thread.hpp>
@ -71,7 +72,8 @@ struct TestMemPoolEntryHelper
bool hadNoDependencies;
bool spendsCoinbase;
unsigned int sigOpCount;
LockPoints lp;
TestMemPoolEntryHelper() :
nFee(0), nTime(0), dPriority(0.0), nHeight(1),
hadNoDependencies(false), spendsCoinbase(false), sigOpCount(1) { }

18
src/txmempool.cpp
View file

@ -22,10 +22,10 @@ using namespace std;
CTxMemPoolEntry::CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee,
int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
bool poolHasNoInputsOf, CAmount _inChainInputValue,
bool _spendsCoinbase, unsigned int _sigOps):
bool _spendsCoinbase, unsigned int _sigOps, LockPoints lp):
tx(_tx), nFee(_nFee), nTime(_nTime), entryPriority(_entryPriority), entryHeight(_entryHeight),
hadNoDependencies(poolHasNoInputsOf), inChainInputValue(_inChainInputValue),
spendsCoinbase(_spendsCoinbase), sigOpCount(_sigOps)
spendsCoinbase(_spendsCoinbase), sigOpCount(_sigOps), lockPoints(lp)
{
nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
nModSize = tx.CalculateModifiedSize(nTxSize);
@ -61,6 +61,11 @@ void CTxMemPoolEntry::UpdateFeeDelta(int64_t newFeeDelta)
feeDelta = newFeeDelta;
}
void CTxMemPoolEntry::UpdateLockPoints(const LockPoints& lp)
{
lockPoints = lp;
}
// Update the given tx for any in-mempool descendants.
// Assumes that setMemPoolChildren is correct for the given tx and all
// descendants.
@ -506,7 +511,11 @@ void CTxMemPool::removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMem
list<CTransaction> transactionsToRemove;
for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
const CTransaction& tx = it->GetTx();
if (!CheckFinalTx(tx, flags) || !CheckSequenceLocks(tx, flags)) {
LockPoints lp = it->GetLockPoints();
bool validLP = TestLockPointValidity(&lp);
if (!CheckFinalTx(tx, flags) || !CheckSequenceLocks(tx, flags, &lp, validLP)) {
// Note if CheckSequenceLocks fails the LockPoints may still be invalid
// So it's critical that we remove the tx and not depend on the LockPoints.
transactionsToRemove.push_back(tx);
} else if (it->GetSpendsCoinbase()) {
BOOST_FOREACH(const CTxIn& txin, tx.vin) {
@ -521,6 +530,9 @@ void CTxMemPool::removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMem
}
}
}
if (!validLP) {
mapTx.modify(it, update_lock_points(lp));
}
}
BOOST_FOREACH(const CTransaction& tx, transactionsToRemove) {
list<CTransaction> removed;

32
src/txmempool.h
View file

@ -19,6 +19,7 @@
#include "boost/multi_index/ordered_index.hpp"
class CAutoFile;
class CBlockIndex;
inline double AllowFreeThreshold()
{
@ -35,6 +36,21 @@ inline bool AllowFree(double dPriority)
/** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
struct LockPoints
{
// Will be set to the blockchain height and median time past
// values that would be necessary to satisfy all relative locktime
// constraints (BIP68) of this tx given our view of block chain history
int height;
int64_t time;
// As long as the current chain descends from the highest height block
// containing one of the inputs used in the calculation, then the cached
// values are still valid even after a reorg.
CBlockIndex* maxInputBlock;
LockPoints() : height(0), time(0), maxInputBlock(NULL) { }
};
class CTxMemPool;
/** \class CTxMemPoolEntry
@ -70,6 +86,7 @@ private:
bool spendsCoinbase; //! keep track of transactions that spend a coinbase
unsigned int sigOpCount; //! Legacy sig ops plus P2SH sig op count
int64_t feeDelta; //! Used for determining the priority of the transaction for mining in a block
LockPoints lockPoints; //! Track the height and time at which tx was final
// Information about descendants of this transaction that are in the
// mempool; if we remove this transaction we must remove all of these
@ -84,7 +101,7 @@ public:
CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee,
int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
bool poolHasNoInputsOf, CAmount _inChainInputValue, bool spendsCoinbase,
unsigned int nSigOps);
unsigned int nSigOps, LockPoints lp);
CTxMemPoolEntry(const CTxMemPoolEntry& other);
const CTransaction& GetTx() const { return this->tx; }
@ -101,12 +118,15 @@ public:
unsigned int GetSigOpCount() const { return sigOpCount; }
int64_t GetModifiedFee() const { return nFee + feeDelta; }
size_t DynamicMemoryUsage() const { return nUsageSize; }
const LockPoints& GetLockPoints() const { return lockPoints; }
// Adjusts the descendant state, if this entry is not dirty.
void UpdateState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount);
// Updates the fee delta used for mining priority score, and the
// modified fees with descendants.
void UpdateFeeDelta(int64_t feeDelta);
// Update the LockPoints after a reorg
void UpdateLockPoints(const LockPoints& lp);
/** We can set the entry to be dirty if doing the full calculation of in-
* mempool descendants will be too expensive, which can potentially happen
@ -154,6 +174,16 @@ private:
int64_t feeDelta;
};
struct update_lock_points
{
update_lock_points(const LockPoints& _lp) : lp(_lp) { }
void operator() (CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
private:
const LockPoints& lp;
};
// extracts a TxMemPoolEntry's transaction hash
struct mempoolentry_txid
{