1 // Copyright (c) 2024-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 5 #include <node/txdownloadman_impl.h>
6 #include <node/txdownloadman.h>
7 8 #include <chain.h>
9 #include <consensus/validation.h>
10 #include <txmempool.h>
11 #include <util/log.h>
12 #include <validation.h>
13 #include <validationinterface.h>
14 15 namespace node {
16 // TxDownloadManager wrappers
17 TxDownloadManager::TxDownloadManager(const TxDownloadOptions& options) :
18 m_impl{std::make_unique<TxDownloadManagerImpl>(options)}
19 {}
20 TxDownloadManager::~TxDownloadManager() = default;
21 22 void TxDownloadManager::ActiveTipChange()
23 {
24 m_impl->ActiveTipChange();
25 }
26 void TxDownloadManager::BlockConnected(const std::shared_ptr<const CBlock>& pblock)
27 {
28 m_impl->BlockConnected(pblock);
29 }
30 void TxDownloadManager::BlockDisconnected()
31 {
32 m_impl->BlockDisconnected();
33 }
34 void TxDownloadManager::ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info)
35 {
36 m_impl->ConnectedPeer(nodeid, info);
37 }
38 void TxDownloadManager::DisconnectedPeer(NodeId nodeid)
39 {
40 m_impl->DisconnectedPeer(nodeid);
41 }
42 bool TxDownloadManager::AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now)
43 {
44 return m_impl->AddTxAnnouncement(peer, gtxid, now);
45 }
46 std::vector<GenTxid> TxDownloadManager::GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time)
47 {
48 return m_impl->GetRequestsToSend(nodeid, current_time);
49 }
50 void TxDownloadManager::ReceivedNotFound(NodeId nodeid, const std::vector<GenTxid>& gtxids)
51 {
52 m_impl->ReceivedNotFound(nodeid, gtxids);
53 }
54 void TxDownloadManager::MempoolAcceptedTx(const CTransactionRef& tx)
55 {
56 m_impl->MempoolAcceptedTx(tx);
57 }
58 RejectedTxTodo TxDownloadManager::MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure)
59 {
60 return m_impl->MempoolRejectedTx(ptx, state, nodeid, first_time_failure);
61 }
62 void TxDownloadManager::MempoolRejectedPackage(const Package& package)
63 {
64 m_impl->MempoolRejectedPackage(package);
65 }
66 std::pair<bool, std::optional<PackageToValidate>> TxDownloadManager::ReceivedTx(NodeId nodeid, const CTransactionRef& ptx)
67 {
68 return m_impl->ReceivedTx(nodeid, ptx);
69 }
70 bool TxDownloadManager::HaveMoreWork(NodeId nodeid) const
71 {
72 return m_impl->HaveMoreWork(nodeid);
73 }
74 CTransactionRef TxDownloadManager::GetTxToReconsider(NodeId nodeid)
75 {
76 return m_impl->GetTxToReconsider(nodeid);
77 }
78 void TxDownloadManager::CheckIsEmpty() const
79 {
80 m_impl->CheckIsEmpty();
81 }
82 void TxDownloadManager::CheckIsEmpty(NodeId nodeid) const
83 {
84 m_impl->CheckIsEmpty(nodeid);
85 }
86 std::vector<TxOrphanage::OrphanInfo> TxDownloadManager::GetOrphanTransactions() const
87 {
88 return m_impl->GetOrphanTransactions();
89 }
90 91 // TxDownloadManagerImpl
92 void TxDownloadManagerImpl::ActiveTipChange()
93 {
94 RecentRejectsFilter().reset();
95 RecentRejectsReconsiderableFilter().reset();
96 }
97 98 void TxDownloadManagerImpl::BlockConnected(const std::shared_ptr<const CBlock>& pblock)
99 {
100 m_orphanage->EraseForBlock(*pblock);
101 102 for (const auto& ptx : pblock->vtx) {
103 RecentConfirmedTransactionsFilter().insert(ptx->GetHash().ToUint256());
104 if (ptx->HasWitness()) {
105 RecentConfirmedTransactionsFilter().insert(ptx->GetWitnessHash().ToUint256());
106 }
107 m_txrequest.ForgetTxHash(ptx->GetHash().ToUint256());
108 m_txrequest.ForgetTxHash(ptx->GetWitnessHash().ToUint256());
109 }
110 }
111 112 void TxDownloadManagerImpl::BlockDisconnected()
113 {
114 // To avoid relay problems with transactions that were previously
115 // confirmed, clear our filter of recently confirmed transactions whenever
116 // there's a reorg.
117 // This means that in a 1-block reorg (where 1 block is disconnected and
118 // then another block reconnected), our filter will drop to having only one
119 // block's worth of transactions in it, but that should be fine, since
120 // presumably the most common case of relaying a confirmed transaction
121 // should be just after a new block containing it is found.
122 RecentConfirmedTransactionsFilter().reset();
123 }
124 125 bool TxDownloadManagerImpl::AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable)
126 {
127 const uint256& hash = gtxid.ToUint256();
128 129 // Never query by txid: it is possible that the transaction in the orphanage has the same
130 // txid but a different witness, which would give us a false positive result. If we decided
131 // not to request the transaction based on this result, an attacker could prevent us from
132 // downloading a transaction by intentionally creating a malleated version of it. While
133 // only one (or none!) of these transactions can ultimately be confirmed, we have no way of
134 // discerning which one that is, so the orphanage can store multiple transactions with the
135 // same txid.
136 //
137 // While we won't query by txid, we can try to "guess" what the wtxid is based on the txid.
138 // A non-segwit transaction's txid == wtxid. Query this txhash "casted" to a wtxid. This will
139 // help us find non-segwit transactions, saving bandwidth, and should have no false positives.
140 if (m_orphanage->HaveTx(Wtxid::FromUint256(hash))) return true;
141 142 if (include_reconsiderable && RecentRejectsReconsiderableFilter().contains(hash)) return true;
143 144 if (RecentConfirmedTransactionsFilter().contains(hash)) return true;
145 146 return RecentRejectsFilter().contains(hash) || std::visit([&](const auto& id) { return m_opts.m_mempool.exists(id); }, gtxid);
147 }
148 149 void TxDownloadManagerImpl::ConnectedPeer(NodeId nodeid, const TxDownloadConnectionInfo& info)
150 {
151 // If already connected (shouldn't happen in practice), exit early.
152 if (m_peer_info.contains(nodeid)) return;
153 154 m_peer_info.try_emplace(nodeid, info);
155 if (info.m_wtxid_relay) m_num_wtxid_peers += 1;
156 }
157 158 void TxDownloadManagerImpl::DisconnectedPeer(NodeId nodeid)
159 {
160 m_orphanage->EraseForPeer(nodeid);
161 m_txrequest.DisconnectedPeer(nodeid);
162 163 if (auto it = m_peer_info.find(nodeid); it != m_peer_info.end()) {
164 if (it->second.m_connection_info.m_wtxid_relay) m_num_wtxid_peers -= 1;
165 m_peer_info.erase(it);
166 }
167 168 }
169 170 bool TxDownloadManagerImpl::AddTxAnnouncement(NodeId peer, const GenTxid& gtxid, std::chrono::microseconds now)
171 {
172 // If this is an orphan we are trying to resolve, consider this peer as a orphan resolution candidate instead.
173 // - is wtxid matching something in orphanage
174 // - exists in orphanage
175 // - peer can be an orphan resolution candidate
176 if (const auto* wtxid = std::get_if<Wtxid>(>xid)) {
177 if (auto orphan_tx{m_orphanage->GetTx(*wtxid)}) {
178 auto unique_parents{GetUniqueParents(*orphan_tx)};
179 std::erase_if(unique_parents, [&](const auto& txid) {
180 return AlreadyHaveTx(txid, /*include_reconsiderable=*/false);
181 });
182 183 // The missing parents may have all been rejected or accepted since the orphan was added to the orphanage.
184 // Do not delete from the orphanage, as it may be queued for processing.
185 if (unique_parents.empty()) {
186 return true;
187 }
188 189 if (MaybeAddOrphanResolutionCandidate(unique_parents, *wtxid, peer, now)) {
190 m_orphanage->AddAnnouncer(orphan_tx->GetWitnessHash(), peer);
191 }
192 193 // Return even if the peer isn't an orphan resolution candidate. This would be caught by AlreadyHaveTx.
194 return true;
195 }
196 }
197 198 // If this is an inv received from a peer and we already have it, we can drop it.
199 if (AlreadyHaveTx(gtxid, /*include_reconsiderable=*/true)) return true;
200 201 auto it = m_peer_info.find(peer);
202 if (it == m_peer_info.end()) return false;
203 const auto& info = it->second.m_connection_info;
204 if (!info.m_relay_permissions && m_txrequest.Count(peer) >= MAX_PEER_TX_ANNOUNCEMENTS) {
205 // Too many queued announcements for this peer
206 return false;
207 }
208 // Decide the TxRequestTracker parameters for this announcement:
209 // - "preferred": if fPreferredDownload is set (= outbound, or NetPermissionFlags::NoBan permission)
210 // - "reqtime": current time plus delays for:
211 // - NONPREF_PEER_TX_DELAY for announcements from non-preferred connections
212 // - TXID_RELAY_DELAY for txid announcements while wtxid peers are available
213 // - OVERLOADED_PEER_TX_DELAY for announcements from peers which have at least
214 // MAX_PEER_TX_REQUEST_IN_FLIGHT requests in flight (and don't have NetPermissionFlags::Relay).
215 auto delay{0us};
216 if (!info.m_preferred) delay += NONPREF_PEER_TX_DELAY;
217 if (!gtxid.IsWtxid() && m_num_wtxid_peers > 0) delay += TXID_RELAY_DELAY;
218 const bool overloaded = !info.m_relay_permissions && m_txrequest.CountInFlight(peer) >= MAX_PEER_TX_REQUEST_IN_FLIGHT;
219 if (overloaded) delay += OVERLOADED_PEER_TX_DELAY;
220 221 m_txrequest.ReceivedInv(peer, gtxid, info.m_preferred, now + delay);
222 223 return false;
224 }
225 226 bool TxDownloadManagerImpl::MaybeAddOrphanResolutionCandidate(const std::vector<Txid>& unique_parents, const Wtxid& wtxid, NodeId nodeid, std::chrono::microseconds now)
227 {
228 auto it_peer = m_peer_info.find(nodeid);
229 if (it_peer == m_peer_info.end()) return false;
230 if (m_orphanage->HaveTxFromPeer(wtxid, nodeid)) return false;
231 232 const auto& peer_entry = m_peer_info.at(nodeid);
233 const auto& info = peer_entry.m_connection_info;
234 235 // TODO: add delays and limits based on the amount of orphan resolution we are already doing
236 // with this peer, how much they are using the orphanage, etc.
237 if (!info.m_relay_permissions) {
238 // This mirrors the delaying and dropping behavior in AddTxAnnouncement in order to preserve
239 // existing behavior: drop if we are tracking too many invs for this peer already. Each
240 // orphan resolution involves at least 1 transaction request which may or may not be
241 // currently tracked in m_txrequest, so we include that in the count.
242 if (m_txrequest.Count(nodeid) + unique_parents.size() > MAX_PEER_TX_ANNOUNCEMENTS) return false;
243 }
244 245 std::chrono::seconds delay{0s};
246 if (!info.m_preferred) delay += NONPREF_PEER_TX_DELAY;
247 // The orphan wtxid is used, but resolution entails requesting the parents by txid. Sometimes
248 // parent and child are announced and thus requested around the same time, and we happen to
249 // receive child sooner. Waiting a few seconds may allow us to cancel the orphan resolution
250 // request if the parent arrives in that time.
251 if (m_num_wtxid_peers > 0) delay += TXID_RELAY_DELAY;
252 const bool overloaded = !info.m_relay_permissions && m_txrequest.CountInFlight(nodeid) >= MAX_PEER_TX_REQUEST_IN_FLIGHT;
253 if (overloaded) delay += OVERLOADED_PEER_TX_DELAY;
254 255 // Treat finding orphan resolution candidate as equivalent to the peer announcing all missing parents.
256 // In the future, orphan resolution may include more explicit steps
257 for (const auto& parent_txid : unique_parents) {
258 m_txrequest.ReceivedInv(nodeid, parent_txid, info.m_preferred, now + delay);
259 }
260 LogDebug(BCLog::TXPACKAGES, "added peer=%d as a candidate for resolving orphan %s\n", nodeid, wtxid.ToString());
261 return true;
262 }
263 264 std::vector<GenTxid> TxDownloadManagerImpl::GetRequestsToSend(NodeId nodeid, std::chrono::microseconds current_time)
265 {
266 std::vector<GenTxid> requests;
267 std::vector<std::pair<NodeId, GenTxid>> expired;
268 auto requestable = m_txrequest.GetRequestable(nodeid, current_time, &expired);
269 for (const auto& [expired_nodeid, gtxid] : expired) {
270 LogDebug(BCLog::NET, "timeout of inflight %s %s from peer=%d\n", gtxid.IsWtxid() ? "wtx" : "tx",
271 gtxid.ToUint256().ToString(), expired_nodeid);
272 }
273 for (const GenTxid& gtxid : requestable) {
274 if (!AlreadyHaveTx(gtxid, /*include_reconsiderable=*/false)) {
275 LogDebug(BCLog::NET, "Requesting %s %s peer=%d\n", gtxid.IsWtxid() ? "wtx" : "tx",
276 gtxid.ToUint256().ToString(), nodeid);
277 requests.emplace_back(gtxid);
278 m_txrequest.RequestedTx(nodeid, gtxid.ToUint256(), current_time + GETDATA_TX_INTERVAL);
279 } else {
280 // We have already seen this transaction, no need to download. This is just a belt-and-suspenders, as
281 // this should already be called whenever a transaction becomes AlreadyHaveTx().
282 m_txrequest.ForgetTxHash(gtxid.ToUint256());
283 }
284 }
285 return requests;
286 }
287 288 void TxDownloadManagerImpl::ReceivedNotFound(NodeId nodeid, const std::vector<GenTxid>& gtxids)
289 {
290 for (const auto& gtxid : gtxids) {
291 // If we receive a NOTFOUND message for a tx we requested, mark the announcement for it as
292 // completed in TxRequestTracker.
293 m_txrequest.ReceivedResponse(nodeid, gtxid.ToUint256());
294 }
295 }
296 297 std::optional<PackageToValidate> TxDownloadManagerImpl::Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid)
298 {
299 const auto& parent_wtxid{ptx->GetWitnessHash()};
300 301 Assume(RecentRejectsReconsiderableFilter().contains(parent_wtxid.ToUint256()));
302 303 // Only consider children from this peer. This helps prevent censorship attempts in which an attacker
304 // sends lots of fake children for the parent, and we (unluckily) keep selecting the fake
305 // children instead of the real one provided by the honest peer. Since we track all announcers
306 // of an orphan, this does not exclude parent + orphan pairs that we happened to request from
307 // different peers.
308 const auto cpfp_candidates_same_peer{m_orphanage->GetChildrenFromSamePeer(ptx, nodeid)};
309 310 // These children should be sorted from newest to oldest. In the (probably uncommon) case
311 // of children that replace each other, this helps us accept the highest feerate (probably the
312 // most recent) one efficiently.
313 for (const auto& child : cpfp_candidates_same_peer) {
314 Package maybe_cpfp_package{ptx, child};
315 if (!RecentRejectsReconsiderableFilter().contains(GetPackageHash(maybe_cpfp_package)) &&
316 !RecentRejectsFilter().contains(child->GetHash().ToUint256())) {
317 return PackageToValidate{ptx, child, nodeid, nodeid};
318 }
319 }
320 return std::nullopt;
321 }
322 323 void TxDownloadManagerImpl::MempoolAcceptedTx(const CTransactionRef& tx)
324 {
325 // As this version of the transaction was acceptable, we can forget about any requests for it.
326 // No-op if the tx is not in txrequest.
327 m_txrequest.ForgetTxHash(tx->GetHash().ToUint256());
328 m_txrequest.ForgetTxHash(tx->GetWitnessHash().ToUint256());
329 330 m_orphanage->AddChildrenToWorkSet(*tx, m_opts.m_rng);
331 // If it came from the orphanage, remove it. No-op if the tx is not in txorphanage.
332 m_orphanage->EraseTx(tx->GetWitnessHash());
333 }
334 335 std::vector<Txid> TxDownloadManagerImpl::GetUniqueParents(const CTransaction& tx)
336 {
337 std::vector<Txid> unique_parents;
338 unique_parents.reserve(tx.vin.size());
339 for (const CTxIn& txin : tx.vin) {
340 // We start with all parents, and then remove duplicates below.
341 unique_parents.push_back(txin.prevout.hash);
342 }
343 344 std::sort(unique_parents.begin(), unique_parents.end());
345 unique_parents.erase(std::unique(unique_parents.begin(), unique_parents.end()), unique_parents.end());
346 347 return unique_parents;
348 }
349 350 node::RejectedTxTodo TxDownloadManagerImpl::MempoolRejectedTx(const CTransactionRef& ptx, const TxValidationState& state, NodeId nodeid, bool first_time_failure)
351 {
352 const CTransaction& tx{*ptx};
353 // Results returned to caller
354 // Whether we should call AddToCompactExtraTransactions at the end
355 bool add_extra_compact_tx{first_time_failure};
356 // Hashes to pass to AddKnownTx later
357 std::vector<Txid> unique_parents;
358 // Populated if failure is reconsiderable and eligible package is found.
359 std::optional<node::PackageToValidate> package_to_validate;
360 361 if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {
362 // Only process a new orphan if this is a first time failure, as otherwise it must be either
363 // already in orphanage or from 1p1c processing.
364 if (first_time_failure && !RecentRejectsFilter().contains(ptx->GetWitnessHash().ToUint256())) {
365 bool fRejectedParents = false; // It may be the case that the orphans parents have all been rejected
366 367 // Deduplicate parent txids, so that we don't have to loop over
368 // the same parent txid more than once down below.
369 unique_parents = GetUniqueParents(tx);
370 371 // Distinguish between parents in m_lazy_recent_rejects and m_lazy_recent_rejects_reconsiderable.
372 // We can tolerate having up to 1 parent in m_lazy_recent_rejects_reconsiderable since we
373 // submit 1p1c packages. However, fail immediately if any are in m_lazy_recent_rejects.
374 std::optional<Txid> rejected_parent_reconsiderable;
375 for (const Txid& parent_txid : unique_parents) {
376 if (RecentRejectsFilter().contains(parent_txid.ToUint256())) {
377 fRejectedParents = true;
378 break;
379 } else if (RecentRejectsReconsiderableFilter().contains(parent_txid.ToUint256()) &&
380 !m_opts.m_mempool.exists(parent_txid)) {
381 // More than 1 parent in m_lazy_recent_rejects_reconsiderable: 1p1c will not be
382 // sufficient to accept this package, so just give up here.
383 if (rejected_parent_reconsiderable.has_value()) {
384 fRejectedParents = true;
385 break;
386 }
387 rejected_parent_reconsiderable = parent_txid;
388 }
389 }
390 if (!fRejectedParents) {
391 // Filter parents that we already have.
392 // Exclude m_lazy_recent_rejects_reconsiderable: the missing parent may have been
393 // previously rejected for being too low feerate. This orphan might CPFP it.
394 std::erase_if(unique_parents, [&](const auto& txid) {
395 return AlreadyHaveTx(txid, /*include_reconsiderable=*/false);
396 });
397 const auto now{GetTime<std::chrono::microseconds>()};
398 const auto& wtxid = ptx->GetWitnessHash();
399 // Potentially flip add_extra_compact_tx to false if tx is already in orphanage, which
400 // means it was already added to vExtraTxnForCompact.
401 add_extra_compact_tx &= !m_orphanage->HaveTx(wtxid);
402 403 // If there is no candidate for orphan resolution, AddTx will not be called. This means
404 // that if a peer is overloading us with invs and orphans, they will eventually not be
405 // able to add any more transactions to the orphanage.
406 //
407 // Search by txid and, if the tx has a witness, wtxid
408 std::vector<NodeId> orphan_resolution_candidates{nodeid};
409 m_txrequest.GetCandidatePeers(ptx->GetHash().ToUint256(), orphan_resolution_candidates);
410 if (ptx->HasWitness()) m_txrequest.GetCandidatePeers(ptx->GetWitnessHash().ToUint256(), orphan_resolution_candidates);
411 412 for (const auto& nodeid : orphan_resolution_candidates) {
413 if (MaybeAddOrphanResolutionCandidate(unique_parents, ptx->GetWitnessHash(), nodeid, now)) {
414 m_orphanage->AddTx(ptx, nodeid);
415 }
416 }
417 418 // Once added to the orphan pool, a tx is considered AlreadyHave, and we shouldn't request it anymore.
419 m_txrequest.ForgetTxHash(tx.GetHash().ToUint256());
420 m_txrequest.ForgetTxHash(tx.GetWitnessHash().ToUint256());
421 } else {
422 unique_parents.clear();
423 LogDebug(BCLog::MEMPOOL, "not keeping orphan with rejected parents %s (wtxid=%s)\n",
424 tx.GetHash().ToString(),
425 tx.GetWitnessHash().ToString());
426 // We will continue to reject this tx since it has rejected
427 // parents so avoid re-requesting it from other peers.
428 // Here we add both the txid and the wtxid, as we know that
429 // regardless of what witness is provided, we will not accept
430 // this, so we don't need to allow for redownload of this txid
431 // from any of our non-wtxidrelay peers.
432 RecentRejectsFilter().insert(tx.GetHash().ToUint256());
433 RecentRejectsFilter().insert(tx.GetWitnessHash().ToUint256());
434 m_txrequest.ForgetTxHash(tx.GetHash().ToUint256());
435 m_txrequest.ForgetTxHash(tx.GetWitnessHash().ToUint256());
436 }
437 }
438 } else if (state.GetResult() == TxValidationResult::TX_WITNESS_STRIPPED) {
439 add_extra_compact_tx = false;
440 } else {
441 // We can add the wtxid of this transaction to our reject filter.
442 // Do not add txids of witness transactions or witness-stripped
443 // transactions to the filter, as they can have been malleated;
444 // adding such txids to the reject filter would potentially
445 // interfere with relay of valid transactions from peers that
446 // do not support wtxid-based relay. See
447 // https://github.com/bitcoin/bitcoin/issues/8279 for details.
448 // We can remove this restriction (and always add wtxids to
449 // the filter even for witness stripped transactions) once
450 // wtxid-based relay is broadly deployed.
451 // See also comments in https://github.com/bitcoin/bitcoin/pull/18044#discussion_r443419034
452 // for concerns around weakening security of unupgraded nodes
453 // if we start doing this too early.
454 if (state.GetResult() == TxValidationResult::TX_RECONSIDERABLE) {
455 // If the result is TX_RECONSIDERABLE, add it to m_lazy_recent_rejects_reconsiderable
456 // because we should not download or submit this transaction by itself again, but may
457 // submit it as part of a package later.
458 RecentRejectsReconsiderableFilter().insert(ptx->GetWitnessHash().ToUint256());
459 460 if (first_time_failure) {
461 // When a transaction fails for TX_RECONSIDERABLE, look for a matching child in the
462 // orphanage, as it is possible that they succeed as a package.
463 LogDebug(BCLog::TXPACKAGES, "tx %s (wtxid=%s) failed but reconsiderable, looking for child in orphanage\n",
464 ptx->GetHash().ToString(), ptx->GetWitnessHash().ToString());
465 package_to_validate = Find1P1CPackage(ptx, nodeid);
466 }
467 } else {
468 RecentRejectsFilter().insert(ptx->GetWitnessHash().ToUint256());
469 }
470 m_txrequest.ForgetTxHash(ptx->GetWitnessHash().ToUint256());
471 // If the transaction failed for TX_INPUTS_NOT_STANDARD,
472 // then we know that the witness was irrelevant to the policy
473 // failure, since this check depends only on the txid
474 // (the scriptPubKey being spent is covered by the txid).
475 // Add the txid to the reject filter to prevent repeated
476 // processing of this transaction in the event that child
477 // transactions are later received (resulting in
478 // parent-fetching by txid via the orphan-handling logic).
479 // We only add the txid if it differs from the wtxid, to avoid wasting entries in the
480 // rolling bloom filter.
481 if (state.GetResult() == TxValidationResult::TX_INPUTS_NOT_STANDARD && ptx->HasWitness()) {
482 RecentRejectsFilter().insert(ptx->GetHash().ToUint256());
483 m_txrequest.ForgetTxHash(ptx->GetHash().ToUint256());
484 }
485 }
486 487 // If the tx failed in ProcessOrphanTx, it should be removed from the orphanage unless the
488 // tx was still missing inputs. If the tx was not in the orphanage, EraseTx does nothing and returns 0.
489 if (state.GetResult() != TxValidationResult::TX_MISSING_INPUTS && m_orphanage->EraseTx(ptx->GetWitnessHash())) {
490 LogDebug(BCLog::TXPACKAGES, " removed orphan tx %s (wtxid=%s)\n", ptx->GetHash().ToString(), ptx->GetWitnessHash().ToString());
491 }
492 493 return RejectedTxTodo{
494 .m_should_add_extra_compact_tx = add_extra_compact_tx,
495 .m_unique_parents = std::move(unique_parents),
496 .m_package_to_validate = std::move(package_to_validate)
497 };
498 }
499 500 void TxDownloadManagerImpl::MempoolRejectedPackage(const Package& package)
501 {
502 RecentRejectsReconsiderableFilter().insert(GetPackageHash(package));
503 }
504 505 std::pair<bool, std::optional<PackageToValidate>> TxDownloadManagerImpl::ReceivedTx(NodeId nodeid, const CTransactionRef& ptx)
506 {
507 const Txid& txid = ptx->GetHash();
508 const Wtxid& wtxid = ptx->GetWitnessHash();
509 510 // Mark that we have received a response
511 m_txrequest.ReceivedResponse(nodeid, txid.ToUint256());
512 if (ptx->HasWitness()) m_txrequest.ReceivedResponse(nodeid, wtxid.ToUint256());
513 514 // First check if we should drop this tx.
515 // We do the AlreadyHaveTx() check using wtxid, rather than txid - in the
516 // absence of witness malleation, this is strictly better, because the
517 // recent rejects filter may contain the wtxid but rarely contains
518 // the txid of a segwit transaction that has been rejected.
519 // In the presence of witness malleation, it's possible that by only
520 // doing the check with wtxid, we could overlook a transaction which
521 // was confirmed with a different witness, or exists in our mempool
522 // with a different witness, but this has limited downside:
523 // mempool validation does its own lookup of whether we have the txid
524 // already; and an adversary can already relay us old transactions
525 // (older than our recency filter) if trying to DoS us, without any need
526 // for witness malleation.
527 if (AlreadyHaveTx(wtxid, /*include_reconsiderable=*/false)) {
528 // If a tx is detected by m_lazy_recent_rejects it is ignored. Because we haven't
529 // submitted the tx to our mempool, we won't have computed a DoS
530 // score for it or determined exactly why we consider it invalid.
531 //
532 // This means we won't penalize any peer subsequently relaying a DoSy
533 // tx (even if we penalized the first peer who gave it to us) because
534 // we have to account for m_lazy_recent_rejects showing false positives. In
535 // other words, we shouldn't penalize a peer if we aren't *sure* they
536 // submitted a DoSy tx.
537 //
538 // Note that m_lazy_recent_rejects doesn't just record DoSy or invalid
539 // transactions, but any tx not accepted by the mempool, which may be
540 // due to node policy (vs. consensus). So we can't blanket penalize a
541 // peer simply for relaying a tx that our m_lazy_recent_rejects has caught,
542 // regardless of false positives.
543 return {false, std::nullopt};
544 } else if (RecentRejectsReconsiderableFilter().contains(wtxid.ToUint256())) {
545 // When a transaction is already in m_lazy_recent_rejects_reconsiderable, we shouldn't submit
546 // it by itself again. However, look for a matching child in the orphanage, as it is
547 // possible that they succeed as a package.
548 LogDebug(BCLog::TXPACKAGES, "found tx %s (wtxid=%s) in reconsiderable rejects, looking for child in orphanage\n",
549 txid.ToString(), wtxid.ToString());
550 return {false, Find1P1CPackage(ptx, nodeid)};
551 }
552 553 554 return {true, std::nullopt};
555 }
556 557 bool TxDownloadManagerImpl::HaveMoreWork(NodeId nodeid)
558 {
559 return m_orphanage->HaveTxToReconsider(nodeid);
560 }
561 562 CTransactionRef TxDownloadManagerImpl::GetTxToReconsider(NodeId nodeid)
563 {
564 return m_orphanage->GetTxToReconsider(nodeid);
565 }
566 567 void TxDownloadManagerImpl::CheckIsEmpty(NodeId nodeid)
568 {
569 assert(m_txrequest.Count(nodeid) == 0);
570 assert(m_orphanage->UsageByPeer(nodeid) == 0);
571 }
572 void TxDownloadManagerImpl::CheckIsEmpty()
573 {
574 assert(m_orphanage->TotalOrphanUsage() == 0);
575 assert(m_orphanage->CountUniqueOrphans() == 0);
576 assert(m_txrequest.Size() == 0);
577 assert(m_num_wtxid_peers == 0);
578 }
579 std::vector<TxOrphanage::OrphanInfo> TxDownloadManagerImpl::GetOrphanTransactions() const
580 {
581 return m_orphanage->GetOrphanTransactions();
582 }
583 } // namespace node
584