/// <summary>
/// Constructs a memory pool feature.
/// </summary>
/// <param name="connectionManager">Connection manager for managing node connections.</param>
/// <param name="signals">Node notifications available to subscribe to.</param>
/// <param name="mempoolSignaled">Observes block 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="nodeSettings">User defined node settings.</param>
/// <param name="loggerFactory">Logger factory for creating instance logger.</param>
/// <param name="mempoolSettings">Mempool settings.</param>
public MempoolFeature(
IConnectionManager connectionManager,
Signals.Signals signals,
MempoolSignaled mempoolSignaled,
MempoolBehavior mempoolBehavior,
MempoolManager mempoolManager,
NodeSettings nodeSettings,
ILoggerFactory loggerFactory,
MempoolSettings mempoolSettings)
{
this.signals = signals;
this.connectionManager = connectionManager;
this.mempoolSignaled = mempoolSignaled;
this.mempoolBehavior = mempoolBehavior;
this.mempoolManager = mempoolManager;
this.mempoolLogger = loggerFactory.CreateLogger(this.GetType().FullName);
this.mempoolSettings = mempoolSettings;
this.nodeSettings = nodeSettings;
}
/// <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)
{
Queue <OutPoint> vWorkQueue = new Queue <OutPoint>();
List <uint256> vEraseQueue = new List <uint256>();
uint256 trxHash = tx.GetHash();
for (int index = 0; index < tx.Outputs.Count; index++)
{
vWorkQueue.Enqueue(new OutPoint(trxHash, index));
}
// Recursively process any orphan transactions that depended on this one
List <ulong> setMisbehaving = new List <ulong>();
while (vWorkQueue.Any())
{
// mapOrphanTransactionsByPrev.TryGet() does a .ToList() to take a new collection
// of orphans as this collection may be modifed later by anotehr thread
List <OrphanTx> itByPrev = await this.MempoolLock.ReadAsync(() => this.mapOrphanTransactionsByPrev.TryGet(vWorkQueue.Dequeue())?.ToList());
if (itByPrev == null)
{
continue;
}
foreach (OrphanTx mi in itByPrev)
{
Transaction orphanTx = mi.Tx; //->second.tx;
uint256 orphanHash = orphanTx.GetHash();
ulong fromPeer = mi.NodeId; // (*mi)->second.fromPeer;
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)
MempoolValidationState stateDummy = new MempoolValidationState(true);
if (await this.Validator.AcceptToMemoryPool(stateDummy, orphanTx))
{
this.mempoolLogger.LogInformation($"accepted orphan tx {orphanHash}");
await behavior.RelayTransaction(orphanTx.GetHash());
this.signals.SignalTransaction(orphanTx);
for (int index = 0; index < orphanTx.Outputs.Count; index++)
{
vWorkQueue.Enqueue(new OutPoint(orphanHash, index));
}
vEraseQueue.Add(orphanHash);
}
else if (!stateDummy.MissingInputs)
{
int nDos = 0;
if (stateDummy.IsInvalid && nDos > 0)
{
// Punish peer that gave us an invalid orphan tx
//Misbehaving(fromPeer, nDos);
setMisbehaving.Add(fromPeer);
this.mempoolLogger.LogInformation($"invalid orphan tx {orphanHash}");
}
// Has inputs but not accepted to mempool
// Probably non-standard or insufficient fee/priority
this.mempoolLogger.LogInformation($"removed orphan tx {orphanHash}");
vEraseQueue.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.
await this.MempoolLock.WriteAsync(() => this.recentRejects.TryAdd(orphanHash, orphanHash));
}
}
this.memPool.Check(new MempoolCoinView(this.coinView, this.memPool, this.MempoolLock, this.Validator));
}
}
foreach (uint256 hash in vEraseQueue)
{
await this.EraseOrphanTx(hash).ConfigureAwait(false);
}
}