diff options
Diffstat (limited to 'src/net_processing.cpp')
| -rw-r--r-- | src/net_processing.cpp | 278 |
1 files changed, 217 insertions, 61 deletions
diff --git a/src/net_processing.cpp b/src/net_processing.cpp index 7a58de35d7..5f1e7318f3 100644 --- a/src/net_processing.cpp +++ b/src/net_processing.cpp @@ -75,6 +75,8 @@ static const unsigned int MAX_INV_SZ = 50000; static constexpr int32_t MAX_PEER_TX_IN_FLIGHT = 100; /** Maximum number of announced transactions from a peer */ static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 2 * MAX_INV_SZ; +/** How many microseconds to delay requesting transactions via txids, if we have wtxid-relaying peers */ +static constexpr std::chrono::microseconds TXID_RELAY_DELAY{std::chrono::seconds{2}}; /** How many microseconds to delay requesting transactions from inbound peers */ static constexpr std::chrono::microseconds INBOUND_PEER_TX_DELAY{std::chrono::seconds{2}}; /** How long to wait (in microseconds) before downloading a transaction from an additional peer */ @@ -151,6 +153,7 @@ struct COrphanTx { }; RecursiveMutex g_cs_orphans; std::map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(g_cs_orphans); +std::map<uint256, std::map<uint256, COrphanTx>::iterator> g_orphans_by_wtxid GUARDED_BY(g_cs_orphans); void EraseOrphansFor(NodeId peer); @@ -187,6 +190,15 @@ namespace { * million to make it highly unlikely for users to have issues with this * filter. * + * We only need to add wtxids to this filter. For non-segwit + * transactions, the txid == wtxid, so this only prevents us from + * re-downloading non-segwit transactions when communicating with + * non-wtxidrelay peers -- which is important for avoiding malleation + * attacks that could otherwise interfere with transaction relay from + * non-wtxidrelay peers. For communicating with wtxidrelay peers, having + * the reject filter store wtxids is exactly what we want to avoid + * redownload of a rejected transaction. + * * Memory used: 1.3 MB */ std::unique_ptr<CRollingBloomFilter> recentRejects GUARDED_BY(cs_main); @@ -218,6 +230,9 @@ namespace { /** Number of peers from which we're downloading blocks. */ int nPeersWithValidatedDownloads GUARDED_BY(cs_main) = 0; + /** Number of peers with wtxid relay. */ + int g_wtxid_relay_peers GUARDED_BY(cs_main) = 0; + /** Number of outbound peers with m_chain_sync.m_protect. */ int g_outbound_peers_with_protect_from_disconnect GUARDED_BY(cs_main) = 0; @@ -409,6 +424,9 @@ struct CNodeState { //! A rolling bloom filter of all announced tx CInvs to this peer. CRollingBloomFilter m_recently_announced_invs = CRollingBloomFilter{INVENTORY_MAX_RECENT_RELAY, 0.000001}; + //! Whether this peer relays txs via wtxid + bool m_wtxid_relay{false}; + CNodeState(CAddress addrIn, std::string addrNameIn, bool is_inbound, bool is_manual) : address(addrIn), name(std::move(addrNameIn)), m_is_inbound(is_inbound), m_is_manual_connection (is_manual) @@ -760,7 +778,7 @@ void UpdateTxRequestTime(const uint256& txid, std::chrono::microseconds request_ } } -std::chrono::microseconds CalculateTxGetDataTime(const uint256& txid, std::chrono::microseconds current_time, bool use_inbound_delay) EXCLUSIVE_LOCKS_REQUIRED(cs_main) +std::chrono::microseconds CalculateTxGetDataTime(const uint256& txid, std::chrono::microseconds current_time, bool use_inbound_delay, bool use_txid_delay) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { std::chrono::microseconds process_time; const auto last_request_time = GetTxRequestTime(txid); @@ -776,6 +794,9 @@ std::chrono::microseconds CalculateTxGetDataTime(const uint256& txid, std::chron // We delay processing announcements from inbound peers if (use_inbound_delay) process_time += INBOUND_PEER_TX_DELAY; + // We delay processing announcements from peers that use txid-relay (instead of wtxid) + if (use_txid_delay) process_time += TXID_RELAY_DELAY; + return process_time; } @@ -793,7 +814,7 @@ void RequestTx(CNodeState* state, const uint256& txid, std::chrono::microseconds // Calculate the time to try requesting this transaction. Use // fPreferredDownload as a proxy for outbound peers. - const auto process_time = CalculateTxGetDataTime(txid, current_time, !state->fPreferredDownload); + const auto process_time = CalculateTxGetDataTime(txid, current_time, !state->fPreferredDownload, !state->m_wtxid_relay && g_wtxid_relay_peers > 0); peer_download_state.m_tx_process_time.emplace(process_time, txid); } @@ -830,14 +851,15 @@ void PeerLogicValidation::InitializeNode(CNode *pnode) { void PeerLogicValidation::ReattemptInitialBroadcast(CScheduler& scheduler) const { - std::set<uint256> unbroadcast_txids = m_mempool.GetUnbroadcastTxs(); + std::map<uint256, uint256> unbroadcast_txids = m_mempool.GetUnbroadcastTxs(); - for (const uint256& txid : unbroadcast_txids) { + for (const auto& elem : unbroadcast_txids) { // Sanity check: all unbroadcast txns should exist in the mempool - if (m_mempool.exists(txid)) { - RelayTransaction(txid, *connman); + if (m_mempool.exists(elem.first)) { + LOCK(cs_main); + RelayTransaction(elem.first, elem.second, *connman); } else { - m_mempool.RemoveUnbroadcastTx(txid, true); + m_mempool.RemoveUnbroadcastTx(elem.first, true); } } @@ -869,6 +891,8 @@ void PeerLogicValidation::FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTim assert(nPeersWithValidatedDownloads >= 0); g_outbound_peers_with_protect_from_disconnect -= state->m_chain_sync.m_protect; assert(g_outbound_peers_with_protect_from_disconnect >= 0); + g_wtxid_relay_peers -= state->m_wtxid_relay; + assert(g_wtxid_relay_peers >= 0); mapNodeState.erase(nodeid); @@ -878,6 +902,7 @@ void PeerLogicValidation::FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTim assert(nPreferredDownload == 0); assert(nPeersWithValidatedDownloads == 0); assert(g_outbound_peers_with_protect_from_disconnect == 0); + assert(g_wtxid_relay_peers == 0); } LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid); } @@ -936,6 +961,8 @@ bool AddOrphanTx(const CTransactionRef& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRE auto ret = mapOrphanTransactions.emplace(hash, COrphanTx{tx, peer, GetTime() + ORPHAN_TX_EXPIRE_TIME, g_orphan_list.size()}); assert(ret.second); g_orphan_list.push_back(ret.first); + // Allow for lookups in the orphan pool by wtxid, as well as txid + g_orphans_by_wtxid.emplace(tx->GetWitnessHash(), ret.first); for (const CTxIn& txin : tx->vin) { mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first); } @@ -972,6 +999,7 @@ int static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) it_last->second.list_pos = old_pos; } g_orphan_list.pop_back(); + g_orphans_by_wtxid.erase(it->second.tx->GetWitnessHash()); mapOrphanTransactions.erase(it); return 1; @@ -1141,6 +1169,7 @@ static bool MaybePunishNodeForTx(NodeId nodeid, const TxValidationState& state, case TxValidationResult::TX_MISSING_INPUTS: case TxValidationResult::TX_PREMATURE_SPEND: case TxValidationResult::TX_WITNESS_MUTATED: + case TxValidationResult::TX_WITNESS_STRIPPED: case TxValidationResult::TX_CONFLICT: case TxValidationResult::TX_MEMPOOL_POLICY: break; @@ -1181,14 +1210,15 @@ PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn, BanMan* banman, CS recentRejects.reset(new CRollingBloomFilter(120000, 0.000001)); // Blocks don't typically have more than 4000 transactions, so this should - // be at least six blocks (~1 hr) worth of transactions that we can store. + // be at least six blocks (~1 hr) worth of transactions that we can store, + // inserting both a txid and wtxid for every observed transaction. // If the number of transactions appearing in a block goes up, or if we are // seeing getdata requests more than an hour after initial announcement, we // can increase this number. // The false positive rate of 1/1M should come out to less than 1 // transaction per day that would be inadvertently ignored (which is the // same probability that we have in the reject filter). - g_recent_confirmed_transactions.reset(new CRollingBloomFilter(24000, 0.000001)); + g_recent_confirmed_transactions.reset(new CRollingBloomFilter(48000, 0.000001)); const Consensus::Params& consensusParams = Params().GetConsensus(); // Stale tip checking and peer eviction are on two different timers, but we @@ -1244,6 +1274,9 @@ void PeerLogicValidation::BlockConnected(const std::shared_ptr<const CBlock>& pb LOCK(g_cs_recent_confirmed_transactions); for (const auto& ptx : pblock->vtx) { g_recent_confirmed_transactions->insert(ptx->GetHash()); + if (ptx->GetHash() != ptx->GetWitnessHash()) { + g_recent_confirmed_transactions->insert(ptx->GetWitnessHash()); + } } } } @@ -1397,6 +1430,7 @@ bool static AlreadyHave(const CInv& inv, const CTxMemPool& mempool) EXCLUSIVE_LO { case MSG_TX: case MSG_WITNESS_TX: + case MSG_WTX: { assert(recentRejects); if (::ChainActive().Tip()->GetBlockHash() != hashRecentRejectsChainTip) @@ -1411,7 +1445,11 @@ bool static AlreadyHave(const CInv& inv, const CTxMemPool& mempool) EXCLUSIVE_LO { LOCK(g_cs_orphans); - if (mapOrphanTransactions.count(inv.hash)) return true; + if (inv.type != MSG_WTX && mapOrphanTransactions.count(inv.hash)) { + return true; + } else if (inv.type == MSG_WTX && g_orphans_by_wtxid.count(inv.hash)) { + return true; + } } { @@ -1419,8 +1457,8 @@ bool static AlreadyHave(const CInv& inv, const CTxMemPool& mempool) EXCLUSIVE_LO if (g_recent_confirmed_transactions->contains(inv.hash)) return true; } - return recentRejects->contains(inv.hash) || - mempool.exists(inv.hash); + const bool by_wtxid = (inv.type == MSG_WTX); + return recentRejects->contains(inv.hash) || mempool.exists(inv.hash, by_wtxid); } case MSG_BLOCK: case MSG_WITNESS_BLOCK: @@ -1430,11 +1468,17 @@ bool static AlreadyHave(const CInv& inv, const CTxMemPool& mempool) EXCLUSIVE_LO return true; } -void RelayTransaction(const uint256& txid, const CConnman& connman) +void RelayTransaction(const uint256& txid, const uint256& wtxid, const CConnman& connman) { - connman.ForEachNode([&txid](CNode* pnode) + connman.ForEachNode([&txid, &wtxid](CNode* pnode) { - pnode->PushTxInventory(txid); + AssertLockHeld(cs_main); + CNodeState &state = *State(pnode->GetId()); + if (state.m_wtxid_relay) { + pnode->PushTxInventory(wtxid); + } else { + pnode->PushTxInventory(txid); + } }); } @@ -1632,9 +1676,9 @@ void static ProcessGetBlockData(CNode& pfrom, const CChainParams& chainparams, c } //! Determine whether or not a peer can request a transaction, and return it (or nullptr if not found or not allowed). -CTransactionRef static FindTxForGetData(const CNode& peer, const uint256& txid, const std::chrono::seconds mempool_req, const std::chrono::seconds now) LOCKS_EXCLUDED(cs_main) +CTransactionRef static FindTxForGetData(const CNode& peer, const uint256& txid_or_wtxid, bool use_wtxid, const std::chrono::seconds mempool_req, const std::chrono::seconds now) LOCKS_EXCLUDED(cs_main) { - auto txinfo = mempool.info(txid); + auto txinfo = mempool.info(txid_or_wtxid, use_wtxid); if (txinfo.tx) { // If a TX could have been INVed in reply to a MEMPOOL request, // or is older than UNCONDITIONAL_RELAY_DELAY, permit the request @@ -1646,13 +1690,12 @@ CTransactionRef static FindTxForGetData(const CNode& peer, const uint256& txid, { LOCK(cs_main); - // Otherwise, the transaction must have been announced recently. - if (State(peer.GetId())->m_recently_announced_invs.contains(txid)) { + if (State(peer.GetId())->m_recently_announced_invs.contains(txid_or_wtxid)) { // If it was, it can be relayed from either the mempool... if (txinfo.tx) return std::move(txinfo.tx); // ... or the relay pool. - auto mi = mapRelay.find(txid); + auto mi = mapRelay.find(txid_or_wtxid); if (mi != mapRelay.end()) return mi->second; } } @@ -1676,7 +1719,7 @@ void static ProcessGetData(CNode& pfrom, const CChainParams& chainparams, CConnm // Process as many TX items from the front of the getdata queue as // possible, since they're common and it's efficient to batch process // them. - while (it != pfrom.vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX)) { + while (it != pfrom.vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX || it->type == MSG_WTX)) { if (interruptMsgProc) return; // The send buffer provides backpressure. If there's no space in // the buffer, pause processing until the next call. @@ -1689,11 +1732,12 @@ void static ProcessGetData(CNode& pfrom, const CChainParams& chainparams, CConnm continue; } - CTransactionRef tx = FindTxForGetData(pfrom, inv.hash, mempool_req, now); + CTransactionRef tx = FindTxForGetData(pfrom, inv.hash, inv.type == MSG_WTX, mempool_req, now); if (tx) { + // WTX and WITNESS_TX imply we serialize with witness int nSendFlags = (inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0); connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *tx)); - mempool.RemoveUnbroadcastTx(inv.hash); + mempool.RemoveUnbroadcastTx(tx->GetHash()); // As we're going to send tx, make sure its unconfirmed parents are made requestable. for (const auto& txin : tx->vin) { auto txinfo = mempool.info(txin.prevout.hash); @@ -1972,7 +2016,7 @@ void static ProcessOrphanTx(CConnman& connman, CTxMemPool& mempool, std::set<uin if (setMisbehaving.count(fromPeer)) continue; if (AcceptToMemoryPool(mempool, orphan_state, porphanTx, &removed_txn, false /* bypass_limits */, 0 /* nAbsurdFee */)) { LogPrint(BCLog::MEMPOOL, " accepted orphan tx %s\n", orphanHash.ToString()); - RelayTransaction(orphanHash, connman); + RelayTransaction(orphanHash, porphanTx->GetWitnessHash(), connman); for (unsigned int i = 0; i < orphanTx.vout.size(); i++) { auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(orphanHash, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { @@ -1997,12 +2041,22 @@ void static ProcessOrphanTx(CConnman& connman, CTxMemPool& mempool, std::set<uin // Has inputs but not accepted to mempool // Probably non-standard or insufficient fee LogPrint(BCLog::MEMPOOL, " removed orphan tx %s\n", orphanHash.ToString()); - if (!orphanTx.HasWitness() && orphan_state.GetResult() != TxValidationResult::TX_WITNESS_MUTATED) { - // 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. + if (orphan_state.GetResult() != TxValidationResult::TX_WITNESS_STRIPPED) { + // We can add the wtxid of this transaction to our reject filter. + // Do not add txids of witness transactions or witness-stripped + // transactions to the filter, as they can have been malleated; + // adding such txids to the reject filter would potentially + // interfere with relay of valid transactions from peers that + // do not support wtxid-based relay. See + // https://github.com/bitcoin/bitcoin/issues/8279 for details. + // We can remove this restriction (and always add wtxids to + // the filter even for witness stripped transactions) once + // wtxid-based relay is broadly deployed. + // See also comments in https://github.com/bitcoin/bitcoin/pull/18044#discussion_r443419034 + // for concerns around weakening security of unupgraded nodes + // if we start doing this too early. assert(recentRejects); - recentRejects->insert(orphanHash); + recentRejects->insert(orphanTx.GetWitnessHash()); } EraseOrphanTx(orphanHash); done = true; @@ -2319,6 +2373,10 @@ void ProcessMessage( if (pfrom.fInbound) PushNodeVersion(pfrom, connman, GetAdjustedTime()); + if (nVersion >= WTXID_RELAY_VERSION) { + connman.PushMessage(&pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::WTXIDRELAY)); + } + connman.PushMessage(&pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERACK)); pfrom.nServices = nServices; @@ -2455,6 +2513,25 @@ void ProcessMessage( return; } + // Feature negotiation of wtxidrelay should happen between VERSION and + // VERACK, to avoid relay problems from switching after a connection is up + if (msg_type == NetMsgType::WTXIDRELAY) { + if (pfrom.fSuccessfullyConnected) { + // Disconnect peers that send wtxidrelay message after VERACK; this + // must be negotiated between VERSION and VERACK. + pfrom.fDisconnect = true; + return; + } + if (pfrom.nVersion >= WTXID_RELAY_VERSION) { + LOCK(cs_main); + if (!State(pfrom.GetId())->m_wtxid_relay) { + State(pfrom.GetId())->m_wtxid_relay = true; + g_wtxid_relay_peers++; + } + } + return; + } + if (!pfrom.fSuccessfullyConnected) { // Must have a verack message before anything else LOCK(cs_main); @@ -2575,6 +2652,13 @@ void ProcessMessage( if (interruptMsgProc) return; + // ignore INVs that don't match wtxidrelay setting + if (State(pfrom.GetId())->m_wtxid_relay) { + if (inv.type == MSG_TX) continue; + } else { + if (inv.type == MSG_WTX) continue; + } + bool fAlreadyHave = AlreadyHave(inv, mempool); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId()); @@ -2593,7 +2677,7 @@ void ProcessMessage( best_block = &inv.hash; } } else { - pfrom.AddInventoryKnown(inv); + pfrom.AddKnownTx(inv.hash); if (fBlocksOnly) { LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol, disconnecting peer=%d\n", inv.hash.ToString(), pfrom.GetId()); pfrom.fDisconnect = true; @@ -2832,26 +2916,50 @@ void ProcessMessage( vRecv >> ptx; const CTransaction& tx = *ptx; - CInv inv(MSG_TX, tx.GetHash()); - pfrom.AddInventoryKnown(inv); + const uint256& txid = ptx->GetHash(); + const uint256& wtxid = ptx->GetWitnessHash(); LOCK2(cs_main, g_cs_orphans); + CNodeState* nodestate = State(pfrom.GetId()); + + const uint256& hash = nodestate->m_wtxid_relay ? wtxid : txid; + pfrom.AddKnownTx(hash); + if (nodestate->m_wtxid_relay && txid != wtxid) { + // Insert txid into filterInventoryKnown, even for + // wtxidrelay peers. This prevents re-adding of + // unconfirmed parents to the recently_announced + // filter, when a child tx is requested. See + // ProcessGetData(). + pfrom.AddKnownTx(txid); + } + TxValidationState state; - CNodeState* nodestate = State(pfrom.GetId()); - nodestate->m_tx_download.m_tx_announced.erase(inv.hash); - nodestate->m_tx_download.m_tx_in_flight.erase(inv.hash); - EraseTxRequest(inv.hash); + nodestate->m_tx_download.m_tx_announced.erase(hash); + nodestate->m_tx_download.m_tx_in_flight.erase(hash); + EraseTxRequest(hash); std::list<CTransactionRef> lRemovedTxn; - if (!AlreadyHave(inv, mempool) && + // We do the AlreadyHave() check using wtxid, rather than txid - in the + // absence of witness malleation, this is strictly better, because the + // recent rejects filter may contain the wtxid but will never contain + // the txid of a segwit transaction that has been rejected. + // In the presence of witness malleation, it's possible that by only + // doing the check with wtxid, we could overlook a transaction which + // was confirmed with a different witness, or exists in our mempool + // with a different witness, but this has limited downside: + // mempool validation does its own lookup of whether we have the txid + // already; and an adversary can already relay us old transactions + // (older than our recency filter) if trying to DoS us, without any need + // for witness malleation. + if (!AlreadyHave(CInv(MSG_WTX, wtxid), mempool) && AcceptToMemoryPool(mempool, state, ptx, &lRemovedTxn, false /* bypass_limits */, 0 /* nAbsurdFee */)) { mempool.check(&::ChainstateActive().CoinsTip()); - RelayTransaction(tx.GetHash(), connman); + RelayTransaction(tx.GetHash(), tx.GetWitnessHash(), connman); for (unsigned int i = 0; i < tx.vout.size(); i++) { - auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(inv.hash, i)); + auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(txid, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { for (const auto& elem : it_by_prev->second) { pfrom.orphan_work_set.insert(elem->first); @@ -2882,10 +2990,17 @@ void ProcessMessage( uint32_t nFetchFlags = GetFetchFlags(pfrom); const auto current_time = GetTime<std::chrono::microseconds>(); - for (const CTxIn& txin : tx.vin) { - CInv _inv(MSG_TX | nFetchFlags, txin.prevout.hash); - pfrom.AddInventoryKnown(_inv); - if (!AlreadyHave(_inv, mempool)) RequestTx(State(pfrom.GetId()), _inv.hash, current_time); + if (!State(pfrom.GetId())->m_wtxid_relay) { + for (const CTxIn& txin : tx.vin) { + // Here, we only have the txid (and not wtxid) of the + // inputs, so we only request parents from + // non-wtxid-relay peers. + // Eventually we should replace this with an improved + // protocol for getting all unconfirmed parents. + CInv _inv(MSG_TX | nFetchFlags, txin.prevout.hash); + pfrom.AddKnownTx(txin.prevout.hash); + if (!AlreadyHave(_inv, mempool)) RequestTx(State(pfrom.GetId()), _inv.hash, current_time); + } } AddOrphanTx(ptx, pfrom.GetId()); @@ -2899,15 +3014,30 @@ void ProcessMessage( LogPrint(BCLog::MEMPOOL, "not keeping orphan with rejected parents %s\n",tx.GetHash().ToString()); // We will continue to reject this tx since it has rejected // parents so avoid re-requesting it from other peers. + // Here we add both the txid and the wtxid, as we know that + // regardless of what witness is provided, we will not accept + // this, so we don't need to allow for redownload of this txid + // from any of our non-wtxidrelay peers. recentRejects->insert(tx.GetHash()); + recentRejects->insert(tx.GetWitnessHash()); } } else { - if (!tx.HasWitness() && state.GetResult() != TxValidationResult::TX_WITNESS_MUTATED) { - // 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. + if (state.GetResult() != TxValidationResult::TX_WITNESS_STRIPPED) { + // We can add the wtxid of this transaction to our reject filter. + // Do not add txids of witness transactions or witness-stripped + // transactions to the filter, as they can have been malleated; + // adding such txids to the reject filter would potentially + // interfere with relay of valid transactions from peers that + // do not support wtxid-based relay. See + // https://github.com/bitcoin/bitcoin/issues/8279 for details. + // We can remove this restriction (and always add wtxids to + // the filter even for witness stripped transactions) once + // wtxid-based relay is broadly deployed. + // See also comments in https://github.com/bitcoin/bitcoin/pull/18044#discussion_r443419034 + // for concerns around weakening security of unupgraded nodes + // if we start doing this too early. assert(recentRejects); - recentRejects->insert(tx.GetHash()); + recentRejects->insert(tx.GetWitnessHash()); if (RecursiveDynamicUsage(*ptx) < 100000) { AddToCompactExtraTransactions(ptx); } @@ -2924,7 +3054,7 @@ void ProcessMessage( LogPrintf("Not relaying non-mempool transaction %s from forcerelay peer=%d\n", tx.GetHash().ToString(), pfrom.GetId()); } else { LogPrintf("Force relaying tx %s from peer=%d\n", tx.GetHash().ToString(), pfrom.GetId()); - RelayTransaction(tx.GetHash(), connman); + RelayTransaction(tx.GetHash(), tx.GetWitnessHash(), connman); } } } @@ -3564,7 +3694,7 @@ void ProcessMessage( vRecv >> vInv; if (vInv.size() <= MAX_PEER_TX_IN_FLIGHT + MAX_BLOCKS_IN_TRANSIT_PER_PEER) { for (CInv &inv : vInv) { - if (inv.type == MSG_TX || inv.type == MSG_WITNESS_TX) { + if (inv.type == MSG_TX || inv.type == MSG_WITNESS_TX || inv.type == MSG_WTX) { // If we receive a NOTFOUND message for a txid we requested, erase // it from our data structures for this peer. auto in_flight_it = state->m_tx_download.m_tx_in_flight.find(inv.hash); @@ -3849,17 +3979,19 @@ namespace { class CompareInvMempoolOrder { CTxMemPool *mp; + bool m_wtxid_relay; public: - explicit CompareInvMempoolOrder(CTxMemPool *_mempool) + explicit CompareInvMempoolOrder(CTxMemPool *_mempool, bool use_wtxid) { mp = _mempool; + m_wtxid_relay = use_wtxid; } bool operator()(std::set<uint256>::iterator a, std::set<uint256>::iterator b) { /* As std::make_heap produces a max-heap, we want the entries with the * fewest ancestors/highest fee to sort later. */ - return mp->CompareDepthAndScore(*b, *a); + return mp->CompareDepthAndScore(*b, *a, m_wtxid_relay); } }; } @@ -4166,8 +4298,8 @@ bool PeerLogicValidation::SendMessages(CNode* pto) LOCK(pto->m_tx_relay->cs_filter); for (const auto& txinfo : vtxinfo) { - const uint256& hash = txinfo.tx->GetHash(); - CInv inv(MSG_TX, hash); + const uint256& hash = state.m_wtxid_relay ? txinfo.tx->GetWitnessHash() : txinfo.tx->GetHash(); + CInv inv(state.m_wtxid_relay ? MSG_WTX : MSG_TX, hash); pto->m_tx_relay->setInventoryTxToSend.erase(hash); // Don't send transactions that peers will not put into their mempool if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) { @@ -4202,7 +4334,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto) } // Topologically and fee-rate sort the inventory we send for privacy and priority reasons. // A heap is used so that not all items need sorting if only a few are being sent. - CompareInvMempoolOrder compareInvMempoolOrder(&m_mempool); + CompareInvMempoolOrder compareInvMempoolOrder(&m_mempool, state.m_wtxid_relay); std::make_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder); // No reason to drain out at many times the network's capacity, // especially since we have many peers and some will draw much shorter delays. @@ -4221,10 +4353,12 @@ bool PeerLogicValidation::SendMessages(CNode* pto) continue; } // Not in the mempool anymore? don't bother sending it. - auto txinfo = m_mempool.info(hash); + auto txinfo = m_mempool.info(hash, state.m_wtxid_relay); if (!txinfo.tx) { continue; } + auto txid = txinfo.tx->GetHash(); + auto wtxid = txinfo.tx->GetWitnessHash(); // Peer told you to not send transactions at that feerate? Don't bother sending it. if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) { continue; @@ -4232,7 +4366,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto) if (pto->m_tx_relay->pfilter && !pto->m_tx_relay->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue; // Send State(pto->GetId())->m_recently_announced_invs.insert(hash); - vInv.push_back(CInv(MSG_TX, hash)); + vInv.push_back(CInv(state.m_wtxid_relay ? MSG_WTX : MSG_TX, hash)); nRelayedTransactions++; { // Expire old relay messages @@ -4242,9 +4376,14 @@ bool PeerLogicValidation::SendMessages(CNode* pto) vRelayExpiration.pop_front(); } - auto ret = mapRelay.insert(std::make_pair(hash, std::move(txinfo.tx))); + auto ret = mapRelay.emplace(txid, std::move(txinfo.tx)); if (ret.second) { - vRelayExpiration.push_back(std::make_pair(nNow + std::chrono::microseconds{RELAY_TX_CACHE_TIME}.count(), ret.first)); + vRelayExpiration.emplace_back(nNow + std::chrono::microseconds{RELAY_TX_CACHE_TIME}.count(), ret.first); + } + // Add wtxid-based lookup into mapRelay as well, so that peers can request by wtxid + auto ret2 = mapRelay.emplace(wtxid, ret.first->second); + if (ret2.second) { + vRelayExpiration.emplace_back(nNow + std::chrono::microseconds{RELAY_TX_CACHE_TIME}.count(), ret2.first); } } if (vInv.size() == MAX_INV_SZ) { @@ -4252,6 +4391,14 @@ bool PeerLogicValidation::SendMessages(CNode* pto) vInv.clear(); } pto->m_tx_relay->filterInventoryKnown.insert(hash); + if (hash != txid) { + // Insert txid into filterInventoryKnown, even for + // wtxidrelay peers. This prevents re-adding of + // unconfirmed parents to the recently_announced + // filter, when a child tx is requested. See + // ProcessGetData(). + pto->m_tx_relay->filterInventoryKnown.insert(txid); + } } } } @@ -4376,7 +4523,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto) // Erase this entry from tx_process_time (it may be added back for // processing at a later time, see below) tx_process_time.erase(tx_process_time.begin()); - CInv inv(MSG_TX | GetFetchFlags(*pto), txid); + CInv inv(state.m_wtxid_relay ? MSG_WTX : (MSG_TX | GetFetchFlags(*pto)), txid); if (!AlreadyHave(inv, m_mempool)) { // If this transaction was last requested more than 1 minute ago, // then request. @@ -4395,7 +4542,15 @@ bool PeerLogicValidation::SendMessages(CNode* pto) // up processing to happen after the download times out // (with a slight delay for inbound peers, to prefer // requests to outbound peers). - const auto next_process_time = CalculateTxGetDataTime(txid, current_time, !state.fPreferredDownload); + // Don't apply the txid-delay to re-requests of a + // transaction; the heuristic of delaying requests to + // txid-relay peers is to save bandwidth on initial + // announcement of a transaction, and doesn't make sense + // for a followup request if our first peer times out (and + // would open us up to an attacker using inbound + // wtxid-relay to prevent us from requesting transactions + // from outbound txid-relay peers). + const auto next_process_time = CalculateTxGetDataTime(txid, current_time, !state.fPreferredDownload, false); tx_process_time.emplace(next_process_time, txid); } } else { @@ -4459,6 +4614,7 @@ public: // orphan transactions mapOrphanTransactions.clear(); mapOrphanTransactionsByPrev.clear(); + g_orphans_by_wtxid.clear(); } }; static CNetProcessingCleanup instance_of_cnetprocessingcleanup; |