/// <summary>
/// Constructs a memory pool feature.
/// </summary>
/// <param name="connectionManager">Connection manager for managing node connections.</param>
/// <param name="mempoolSignaled">Observes block signal notifications from signals.</param>
/// <param name="blocksDisconnectedSignaled">Observes reorged headers signal notifications from signals.</param>
/// <param name="mempoolBehavior">Memory pool node behavior for managing attached node messages.</param>
/// <param name="mempoolManager">Memory pool manager for managing external access to memory pool.</param>
/// <param name="loggerFactory">Logger factory for creating instance logger.</param>
public MempoolFeature(
IConnectionManager connectionManager,
MempoolSignaled mempoolSignaled,
BlocksDisconnectedSignaled blocksDisconnectedSignaled,
MempoolBehavior mempoolBehavior,
MempoolManager mempoolManager,
ILoggerFactory loggerFactory,
INodeStats nodeStats)
{
this.connectionManager = connectionManager;
this.mempoolSignaled = mempoolSignaled;
this.blocksDisconnectedSignaled = blocksDisconnectedSignaled;
this.mempoolBehavior = mempoolBehavior;
this.mempoolManager = mempoolManager;
this.logger = loggerFactory.CreateLogger(GetType().FullName);
nodeStats.RegisterStats(AddComponentStats, StatsType.Component, GetType().Name);
}
/// <summary>
/// Processes orphan transactions.
/// Executed when receive a new transaction through MempoolBehavior.
/// </summary>
/// <param name="behavior">Memory pool behavior that received new transaction.</param>
/// <param name="tx">The new transaction received.</param>
public async Task ProcessesOrphansAsync(MempoolBehavior behavior, Transaction tx)
{
var workQueue = new Queue <OutPoint>();
var eraseQueue = new List <uint256>();
var trxHash = tx.GetHash();
for (var index = 0; index < tx.Outputs.Count; index++)
{
workQueue.Enqueue(new OutPoint(trxHash, index));
}
// Recursively process any orphan transactions that depended on this one
var setMisbehaving = new List <ulong>();
while (workQueue.Any())
{
List <OrphanTx> itByPrev = null;
lock (this.lockObject)
{
var prevOrphans = this.mapOrphanTransactionsByPrev.TryGet(workQueue.Dequeue());
if (prevOrphans != null)
{
// Create a copy of the list so we can manage it outside of the lock.
itByPrev = prevOrphans.ToList();
}
}
if (itByPrev == null)
{
continue;
}
foreach (var mi in itByPrev)
{
var orphanTx = mi.Tx;
var orphanHash = orphanTx.GetHash();
var fromPeer = mi.NodeId;
if (setMisbehaving.Contains(fromPeer))
{
continue;
}
// Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan
// resolution (that is, feeding people an invalid transaction based on LegitTxX in order to get
// anyone relaying LegitTxX banned)
var stateDummy = new MempoolValidationState(true);
if (await this.Validator.AcceptToMemoryPool(stateDummy, orphanTx))
{
this.logger.LogInformation("accepted orphan tx {0}", orphanHash);
behavior.RelayTransaction(orphanTx.GetHash());
this.signals.Publish(new TransactionReceived(orphanTx));
for (var index = 0; index < orphanTx.Outputs.Count; index++)
{
workQueue.Enqueue(new OutPoint(orphanHash, index));
}
eraseQueue.Add(orphanHash);
}
else if (!stateDummy.MissingInputs)
{
var nDos = 0;
if (stateDummy.IsInvalid && nDos > 0)
{
// Punish peer that gave us an invalid orphan tx
//Misbehaving(fromPeer, nDos);
setMisbehaving.Add(fromPeer);
this.logger.LogInformation("invalid orphan tx {0}", orphanHash);
}
// Has inputs but not accepted to mempool
// Probably non-standard or insufficient fee/priority
this.logger.LogInformation("removed orphan tx {0}", orphanHash);
eraseQueue.Add(orphanHash);
if (!orphanTx.HasWitness && !stateDummy.CorruptionPossible)
{
// Do not use rejection cache for witness transactions or
// witness-stripped transactions, as they can have been malleated.
// See https://github.com/bitcoin/bitcoin/issues/8279 for details.
AddToRecentRejects(orphanHash);
}
}
// TODO: implement sanity checks.
//this.memPool.Check(new MempoolCoinView(this.coinView, this.memPool, this.MempoolLock, this.Validator));
}
}
if (eraseQueue.Count > 0)
{
lock (this.lockObject)
{
foreach (var hash in eraseQueue)
{
EraseOrphanTxLock(hash);
}
}
}
}