// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2020 The Bitcoin Core developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // For NDEBUG compile time check #include #include #include #include #include /** Expiration time for orphan transactions in seconds */ static constexpr int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60; /** Minimum time between orphan transactions expire time checks in seconds */ static constexpr int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60; /** How long to cache transactions in mapRelay for normal relay */ static constexpr std::chrono::seconds RELAY_TX_CACHE_TIME = std::chrono::minutes{15}; /** How long a transaction has to be in the mempool before it can unconditionally be relayed (even when not in mapRelay). */ static constexpr std::chrono::seconds UNCONDITIONAL_RELAY_DELAY = std::chrono::minutes{2}; /** Headers download timeout expressed in microseconds * Timeout = base + per_header * (expected number of headers) */ static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_BASE = 15 * 60 * 1000000; // 15 minutes static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1000; // 1ms/header /** Protect at least this many outbound peers from disconnection due to slow/ * behind headers chain. */ static constexpr int32_t MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT = 4; /** Timeout for (unprotected) outbound peers to sync to our chainwork, in seconds */ static constexpr int64_t CHAIN_SYNC_TIMEOUT = 20 * 60; // 20 minutes /** How frequently to check for stale tips, in seconds */ static constexpr int64_t STALE_CHECK_INTERVAL = 10 * 60; // 10 minutes /** How frequently to check for extra outbound peers and disconnect, in seconds */ static constexpr int64_t EXTRA_PEER_CHECK_INTERVAL = 45; /** Minimum time an outbound-peer-eviction candidate must be connected for, in order to evict, in seconds */ static constexpr int64_t MINIMUM_CONNECT_TIME = 30; /** SHA256("main address relay")[0:8] */ static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL; /// Age after which a stale block will no longer be served if requested as /// protection against fingerprinting. Set to one month, denominated in seconds. static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60; /// Age after which a block is considered historical for purposes of rate /// limiting block relay. Set to one week, denominated in seconds. static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60; /** Time between pings automatically sent out for latency probing and keepalive */ static constexpr std::chrono::minutes PING_INTERVAL{2}; /** The maximum number of entries in a locator */ static const unsigned int MAX_LOCATOR_SZ = 101; /** The maximum number of entries in an 'inv' protocol message */ static const unsigned int MAX_INV_SZ = 50000; /** Maximum number of in-flight transaction requests from a peer. It is not a hard limit, but the threshold at which * point the OVERLOADED_PEER_TX_DELAY kicks in. */ static constexpr int32_t MAX_PEER_TX_REQUEST_IN_FLIGHT = 100; /** Maximum number of transactions to consider for requesting, per peer. It provides a reasonable DoS limit to * per-peer memory usage spent on announcements, while covering peers continuously sending INVs at the maximum * rate (by our own policy, see INVENTORY_BROADCAST_PER_SECOND) for several minutes, while not receiving * the actual transaction (from any peer) in response to requests for them. */ static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 5000; /** How long to delay requesting transactions via txids, if we have wtxid-relaying peers */ static constexpr auto TXID_RELAY_DELAY = std::chrono::seconds{2}; /** How long to delay requesting transactions from non-preferred peers */ static constexpr auto NONPREF_PEER_TX_DELAY = std::chrono::seconds{2}; /** How long to delay requesting transactions from overloaded peers (see MAX_PEER_TX_REQUEST_IN_FLIGHT). */ static constexpr auto OVERLOADED_PEER_TX_DELAY = std::chrono::seconds{2}; /** How long to wait (in microseconds) before downloading a transaction from an additional peer */ static constexpr std::chrono::microseconds GETDATA_TX_INTERVAL{std::chrono::seconds{60}}; /** Limit to avoid sending big packets. Not used in processing incoming GETDATA for compatibility */ static const unsigned int MAX_GETDATA_SZ = 1000; /** Number of blocks that can be requested at any given time from a single peer. */ static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16; /** Timeout in seconds during which a peer must stall block download progress before being disconnected. */ static const unsigned int BLOCK_STALLING_TIMEOUT = 2; /** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends * less than this number, we reached its tip. Changing this value is a protocol upgrade. */ static const unsigned int MAX_HEADERS_RESULTS = 2000; /** Maximum depth of blocks we're willing to serve as compact blocks to peers * when requested. For older blocks, a regular BLOCK response will be sent. */ static const int MAX_CMPCTBLOCK_DEPTH = 5; /** Maximum depth of blocks we're willing to respond to GETBLOCKTXN requests for. */ static const int MAX_BLOCKTXN_DEPTH = 10; /** Size of the "block download window": how far ahead of our current height do we fetch? * Larger windows tolerate larger download speed differences between peer, but increase the potential * degree of disordering of blocks on disk (which make reindexing and pruning harder). We'll probably * want to make this a per-peer adaptive value at some point. */ static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024; /** Block download timeout base, expressed in millionths of the block interval (i.e. 10 min) */ static const int64_t BLOCK_DOWNLOAD_TIMEOUT_BASE = 1000000; /** Additional block download timeout per parallel downloading peer (i.e. 5 min) */ static const int64_t BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 500000; /** Maximum number of headers to announce when relaying blocks with headers message.*/ static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8; /** Maximum number of unconnecting headers announcements before DoS score */ static const int MAX_UNCONNECTING_HEADERS = 10; /** Minimum blocks required to signal NODE_NETWORK_LIMITED */ static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288; /** Average delay between local address broadcasts */ static constexpr std::chrono::hours AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24}; /** Average delay between peer address broadcasts */ static constexpr std::chrono::seconds AVG_ADDRESS_BROADCAST_INTERVAL{30}; /** Average delay between trickled inventory transmissions in seconds. * Blocks and peers with noban permission bypass this, outbound peers get half this delay. */ static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5; /** Maximum rate of inventory items to send per second. * Limits the impact of low-fee transaction floods. */ static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND = 7; /** Maximum number of inventory items to send per transmission. */ static constexpr unsigned int INVENTORY_BROADCAST_MAX = INVENTORY_BROADCAST_PER_SECOND * INVENTORY_BROADCAST_INTERVAL; /** The number of most recently announced transactions a peer can request. */ static constexpr unsigned int INVENTORY_MAX_RECENT_RELAY = 3500; /** Verify that INVENTORY_MAX_RECENT_RELAY is enough to cache everything typically * relayed before unconditional relay from the mempool kicks in. This is only a * lower bound, and it should be larger to account for higher inv rate to outbound * peers, and random variations in the broadcast mechanism. */ static_assert(INVENTORY_MAX_RECENT_RELAY >= INVENTORY_BROADCAST_PER_SECOND * UNCONDITIONAL_RELAY_DELAY / std::chrono::seconds{1}, "INVENTORY_RELAY_MAX too low"); /** Average delay between feefilter broadcasts in seconds. */ static constexpr unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60; /** Maximum feefilter broadcast delay after significant change. */ static constexpr unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60; /** Maximum number of compact filters that may be requested with one getcfilters. See BIP 157. */ static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000; /** Maximum number of cf hashes that may be requested with one getcfheaders. See BIP 157. */ static constexpr uint32_t MAX_GETCFHEADERS_SIZE = 2000; /** the maximum percentage of addresses from our addrman to return in response to a getaddr message. */ static constexpr size_t MAX_PCT_ADDR_TO_SEND = 23; struct COrphanTx { // When modifying, adapt the copy of this definition in tests/DoS_tests. CTransactionRef tx; NodeId fromPeer; int64_t nTimeExpire; size_t list_pos; }; /** Guards orphan transactions and extra txs for compact blocks */ RecursiveMutex g_cs_orphans; /** Map from txid to orphan transaction record. Limited by * -maxorphantx/DEFAULT_MAX_ORPHAN_TRANSACTIONS */ std::map mapOrphanTransactions GUARDED_BY(g_cs_orphans); /** Index from wtxid into the mapOrphanTransactions to lookup orphan * transactions using their witness ids. */ std::map::iterator> g_orphans_by_wtxid GUARDED_BY(g_cs_orphans); void EraseOrphansFor(NodeId peer); // Internal stuff namespace { /** Number of nodes with fSyncStarted. */ int nSyncStarted GUARDED_BY(cs_main) = 0; /** * Sources of received blocks, saved to be able punish them when processing * happens afterwards. * Set mapBlockSource[hash].second to false if the node should not be * punished if the block is invalid. */ std::map> mapBlockSource GUARDED_BY(cs_main); /** * Filter for transactions that were recently rejected by * AcceptToMemoryPool. These are not rerequested until the chain tip * changes, at which point the entire filter is reset. * * Without this filter we'd be re-requesting txs from each of our peers, * increasing bandwidth consumption considerably. For instance, with 100 * peers, half of which relay a tx we don't accept, that might be a 50x * bandwidth increase. A flooding attacker attempting to roll-over the * filter using minimum-sized, 60byte, transactions might manage to send * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a * two minute window to send invs to us. * * Decreasing the false positive rate is fairly cheap, so we pick one in a * million to make it highly unlikely for users to have issues with this * filter. * * We typically only 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. * * In cases where we can tell that a segwit transaction will fail * validation no matter the witness, we may add the txid of such * transaction to the filter as well. This can be helpful when * communicating with txid-relay peers or if we were to otherwise fetch a * transaction via txid (eg in our orphan handling). * * Memory used: 1.3 MB */ std::unique_ptr recentRejects GUARDED_BY(cs_main); uint256 hashRecentRejectsChainTip GUARDED_BY(cs_main); /* * Filter for transactions that have been recently confirmed. * We use this to avoid requesting transactions that have already been * confirnmed. */ Mutex g_cs_recent_confirmed_transactions; std::unique_ptr g_recent_confirmed_transactions GUARDED_BY(g_cs_recent_confirmed_transactions); /** Blocks that are in flight, and that are in the queue to be downloaded. */ struct QueuedBlock { uint256 hash; const CBlockIndex* pindex; //!< Optional. bool fValidatedHeaders; //!< Whether this block has validated headers at the time of request. std::unique_ptr partialBlock; //!< Optional, used for CMPCTBLOCK downloads }; std::map::iterator> > mapBlocksInFlight GUARDED_BY(cs_main); /** Stack of nodes which we have set to announce using compact blocks */ std::list lNodesAnnouncingHeaderAndIDs GUARDED_BY(cs_main); /** Number of preferable block download peers. */ int nPreferredDownload GUARDED_BY(cs_main) = 0; /** 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; /** When our tip was last updated. */ std::atomic g_last_tip_update(0); /** Relay map (txid or wtxid -> CTransactionRef) */ typedef std::map MapRelay; MapRelay mapRelay GUARDED_BY(cs_main); /** Expiration-time ordered list of (expire time, relay map entry) pairs. */ std::deque> vRelayExpiration GUARDED_BY(cs_main); struct IteratorComparator { template bool operator()(const I& a, const I& b) const { return &(*a) < &(*b); } }; /** Index from the parents' COutPoint into the mapOrphanTransactions. Used * to remove orphan transactions from the mapOrphanTransactions */ std::map::iterator, IteratorComparator>> mapOrphanTransactionsByPrev GUARDED_BY(g_cs_orphans); /** Orphan transactions in vector for quick random eviction */ std::vector::iterator> g_orphan_list GUARDED_BY(g_cs_orphans); /** Orphan/conflicted/etc transactions that are kept for compact block reconstruction. * The last -blockreconstructionextratxn/DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN of * these are kept in a ring buffer */ static std::vector> vExtraTxnForCompact GUARDED_BY(g_cs_orphans); /** Offset into vExtraTxnForCompact to insert the next tx */ static size_t vExtraTxnForCompactIt GUARDED_BY(g_cs_orphans) = 0; } // namespace namespace { /** * Maintain validation-specific state about nodes, protected by cs_main, instead * by CNode's own locks. This simplifies asynchronous operation, where * processing of incoming data is done after the ProcessMessage call returns, * and we're no longer holding the node's locks. */ struct CNodeState { //! The peer's address const CService address; //! The best known block we know this peer has announced. const CBlockIndex *pindexBestKnownBlock; //! The hash of the last unknown block this peer has announced. uint256 hashLastUnknownBlock; //! The last full block we both have. const CBlockIndex *pindexLastCommonBlock; //! The best header we have sent our peer. const CBlockIndex *pindexBestHeaderSent; //! Length of current-streak of unconnecting headers announcements int nUnconnectingHeaders; //! Whether we've started headers synchronization with this peer. bool fSyncStarted; //! When to potentially disconnect peer for stalling headers download int64_t nHeadersSyncTimeout; //! Since when we're stalling block download progress (in microseconds), or 0. int64_t nStallingSince; std::list vBlocksInFlight; //! When the first entry in vBlocksInFlight started downloading. Don't care when vBlocksInFlight is empty. int64_t nDownloadingSince; int nBlocksInFlight; int nBlocksInFlightValidHeaders; //! Whether we consider this a preferred download peer. bool fPreferredDownload; //! Whether this peer wants invs or headers (when possible) for block announcements. bool fPreferHeaders; //! Whether this peer wants invs or cmpctblocks (when possible) for block announcements. bool fPreferHeaderAndIDs; /** * Whether this peer will send us cmpctblocks if we request them. * This is not used to gate request logic, as we really only care about fSupportsDesiredCmpctVersion, * but is used as a flag to "lock in" the version of compact blocks (fWantsCmpctWitness) we send. */ bool fProvidesHeaderAndIDs; //! Whether this peer can give us witnesses bool fHaveWitness; //! Whether this peer wants witnesses in cmpctblocks/blocktxns bool fWantsCmpctWitness; /** * If we've announced NODE_WITNESS to this peer: whether the peer sends witnesses in cmpctblocks/blocktxns, * otherwise: whether this peer sends non-witnesses in cmpctblocks/blocktxns. */ bool fSupportsDesiredCmpctVersion; /** State used to enforce CHAIN_SYNC_TIMEOUT and EXTRA_PEER_CHECK_INTERVAL logic. * * Both are only in effect for outbound, non-manual, non-protected connections. * Any peer protected (m_protect = true) is not chosen for eviction. A peer is * marked as protected if all of these are true: * - its connection type is IsBlockOnlyConn() == false * - it gave us a valid connecting header * - we haven't reached MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT yet * - it has a better chain than we have * * CHAIN_SYNC_TIMEOUT: if a peer's best known block has less work than our tip, * set a timeout CHAIN_SYNC_TIMEOUT seconds in the future: * - If at timeout their best known block now has more work than our tip * when the timeout was set, then either reset the timeout or clear it * (after comparing against our current tip's work) * - If at timeout their best known block still has less work than our * tip did when the timeout was set, then send a getheaders message, * and set a shorter timeout, HEADERS_RESPONSE_TIME seconds in future. * If their best known block is still behind when that new timeout is * reached, disconnect. * * EXTRA_PEER_CHECK_INTERVAL: after each interval, if we have too many outbound peers, * drop the outbound one that least recently announced us a new block. */ struct ChainSyncTimeoutState { //! A timeout used for checking whether our peer has sufficiently synced int64_t m_timeout; //! A header with the work we require on our peer's chain const CBlockIndex * m_work_header; //! After timeout is reached, set to true after sending getheaders bool m_sent_getheaders; //! Whether this peer is protected from disconnection due to a bad/slow chain bool m_protect; }; ChainSyncTimeoutState m_chain_sync; //! Time of last new block announcement int64_t m_last_block_announcement; //! Whether this peer is an inbound connection bool m_is_inbound; //! 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, bool is_inbound) : address(addrIn), m_is_inbound(is_inbound) { pindexBestKnownBlock = nullptr; hashLastUnknownBlock.SetNull(); pindexLastCommonBlock = nullptr; pindexBestHeaderSent = nullptr; nUnconnectingHeaders = 0; fSyncStarted = false; nHeadersSyncTimeout = 0; nStallingSince = 0; nDownloadingSince = 0; nBlocksInFlight = 0; nBlocksInFlightValidHeaders = 0; fPreferredDownload = false; fPreferHeaders = false; fPreferHeaderAndIDs = false; fProvidesHeaderAndIDs = false; fHaveWitness = false; fWantsCmpctWitness = false; fSupportsDesiredCmpctVersion = false; m_chain_sync = { 0, nullptr, false, false }; m_last_block_announcement = 0; m_recently_announced_invs.reset(); } }; /** Map maintaining per-node state. */ static std::map mapNodeState GUARDED_BY(cs_main); static CNodeState *State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { std::map::iterator it = mapNodeState.find(pnode); if (it == mapNodeState.end()) return nullptr; return &it->second; } static void UpdatePreferredDownload(const CNode& node, CNodeState* state) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { nPreferredDownload -= state->fPreferredDownload; // Whether this node should be marked as a preferred download node. state->fPreferredDownload = (!node.IsInboundConn() || node.HasPermission(PF_NOBAN)) && !node.IsAddrFetchConn() && !node.fClient; nPreferredDownload += state->fPreferredDownload; } // Returns a bool indicating whether we requested this block. // Also used if a block was /not/ received and timed out or started with another peer static bool MarkBlockAsReceived(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { std::map::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash); if (itInFlight != mapBlocksInFlight.end()) { CNodeState *state = State(itInFlight->second.first); assert(state != nullptr); state->nBlocksInFlightValidHeaders -= itInFlight->second.second->fValidatedHeaders; if (state->nBlocksInFlightValidHeaders == 0 && itInFlight->second.second->fValidatedHeaders) { // Last validated block on the queue was received. nPeersWithValidatedDownloads--; } if (state->vBlocksInFlight.begin() == itInFlight->second.second) { // First block on the queue was received, update the start download time for the next one state->nDownloadingSince = std::max(state->nDownloadingSince, count_microseconds(GetTime())); } state->vBlocksInFlight.erase(itInFlight->second.second); state->nBlocksInFlight--; state->nStallingSince = 0; mapBlocksInFlight.erase(itInFlight); return true; } return false; } // returns false, still setting pit, if the block was already in flight from the same peer // pit will only be valid as long as the same cs_main lock is being held static bool MarkBlockAsInFlight(CTxMemPool& mempool, NodeId nodeid, const uint256& hash, const CBlockIndex* pindex = nullptr, std::list::iterator** pit = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { CNodeState *state = State(nodeid); assert(state != nullptr); // Short-circuit most stuff in case it is from the same node std::map::iterator> >::iterator itInFlight = mapBlocksInFlight.find(hash); if (itInFlight != mapBlocksInFlight.end() && itInFlight->second.first == nodeid) { if (pit) { *pit = &itInFlight->second.second; } return false; } // Make sure it's not listed somewhere already. MarkBlockAsReceived(hash); std::list::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(), {hash, pindex, pindex != nullptr, std::unique_ptr(pit ? new PartiallyDownloadedBlock(&mempool) : nullptr)}); state->nBlocksInFlight++; state->nBlocksInFlightValidHeaders += it->fValidatedHeaders; if (state->nBlocksInFlight == 1) { // We're starting a block download (batch) from this peer. state->nDownloadingSince = GetTime().count(); } if (state->nBlocksInFlightValidHeaders == 1 && pindex != nullptr) { nPeersWithValidatedDownloads++; } itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it))).first; if (pit) *pit = &itInFlight->second.second; return true; } /** Check whether the last unknown block a peer advertised is not yet known. */ static void ProcessBlockAvailability(NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { CNodeState *state = State(nodeid); assert(state != nullptr); if (!state->hashLastUnknownBlock.IsNull()) { const CBlockIndex* pindex = LookupBlockIndex(state->hashLastUnknownBlock); if (pindex && pindex->nChainWork > 0) { if (state->pindexBestKnownBlock == nullptr || pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) { state->pindexBestKnownBlock = pindex; } state->hashLastUnknownBlock.SetNull(); } } } /** Update tracking information about which blocks a peer is assumed to have. */ static void UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { CNodeState *state = State(nodeid); assert(state != nullptr); ProcessBlockAvailability(nodeid); const CBlockIndex* pindex = LookupBlockIndex(hash); if (pindex && pindex->nChainWork > 0) { // An actually better block was announced. if (state->pindexBestKnownBlock == nullptr || pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) { state->pindexBestKnownBlock = pindex; } } else { // An unknown block was announced; just assume that the latest one is the best one. state->hashLastUnknownBlock = hash; } } /** * When a peer sends us a valid block, instruct it to announce blocks to us * using CMPCTBLOCK if possible by adding its nodeid to the end of * lNodesAnnouncingHeaderAndIDs, and keeping that list under a certain size by * removing the first element if necessary. */ static void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid, CConnman& connman) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); CNodeState* nodestate = State(nodeid); if (!nodestate || !nodestate->fSupportsDesiredCmpctVersion) { // Never ask from peers who can't provide witnesses. return; } if (nodestate->fProvidesHeaderAndIDs) { for (std::list::iterator it = lNodesAnnouncingHeaderAndIDs.begin(); it != lNodesAnnouncingHeaderAndIDs.end(); it++) { if (*it == nodeid) { lNodesAnnouncingHeaderAndIDs.erase(it); lNodesAnnouncingHeaderAndIDs.push_back(nodeid); return; } } connman.ForNode(nodeid, [&connman](CNode* pfrom) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); uint64_t nCMPCTBLOCKVersion = (pfrom->GetLocalServices() & NODE_WITNESS) ? 2 : 1; if (lNodesAnnouncingHeaderAndIDs.size() >= 3) { // As per BIP152, we only get 3 of our peers to announce // blocks using compact encodings. connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(), [&connman, nCMPCTBLOCKVersion](CNode* pnodeStop){ connman.PushMessage(pnodeStop, CNetMsgMaker(pnodeStop->GetCommonVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/false, nCMPCTBLOCKVersion)); // save BIP152 bandwidth state: we select peer to be low-bandwidth pnodeStop->m_bip152_highbandwidth_to = false; return true; }); lNodesAnnouncingHeaderAndIDs.pop_front(); } connman.PushMessage(pfrom, CNetMsgMaker(pfrom->GetCommonVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/true, nCMPCTBLOCKVersion)); // save BIP152 bandwidth state: we select peer to be high-bandwidth pfrom->m_bip152_highbandwidth_to = true; lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId()); return true; }); } } static bool TipMayBeStale(const Consensus::Params &consensusParams) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); if (g_last_tip_update == 0) { g_last_tip_update = GetTime(); } return g_last_tip_update < GetTime() - consensusParams.nPowTargetSpacing * 3 && mapBlocksInFlight.empty(); } static bool CanDirectFetch(const Consensus::Params &consensusParams) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return ::ChainActive().Tip()->GetBlockTime() > GetAdjustedTime() - consensusParams.nPowTargetSpacing * 20; } static bool PeerHasHeader(CNodeState *state, const CBlockIndex *pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { if (state->pindexBestKnownBlock && pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight)) return true; if (state->pindexBestHeaderSent && pindex == state->pindexBestHeaderSent->GetAncestor(pindex->nHeight)) return true; return false; } /** Update pindexLastCommonBlock and add not-in-flight missing successors to vBlocks, until it has * at most count entries. */ static void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vector& vBlocks, NodeId& nodeStaller, const Consensus::Params& consensusParams) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { if (count == 0) return; vBlocks.reserve(vBlocks.size() + count); CNodeState *state = State(nodeid); assert(state != nullptr); // Make sure pindexBestKnownBlock is up to date, we'll need it. ProcessBlockAvailability(nodeid); if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->nChainWork < ::ChainActive().Tip()->nChainWork || state->pindexBestKnownBlock->nChainWork < nMinimumChainWork) { // This peer has nothing interesting. return; } if (state->pindexLastCommonBlock == nullptr) { // Bootstrap quickly by guessing a parent of our best tip is the forking point. // Guessing wrong in either direction is not a problem. state->pindexLastCommonBlock = ::ChainActive()[std::min(state->pindexBestKnownBlock->nHeight, ::ChainActive().Height())]; } // If the peer reorganized, our previous pindexLastCommonBlock may not be an ancestor // of its current tip anymore. Go back enough to fix that. state->pindexLastCommonBlock = LastCommonAncestor(state->pindexLastCommonBlock, state->pindexBestKnownBlock); if (state->pindexLastCommonBlock == state->pindexBestKnownBlock) return; std::vector vToFetch; const CBlockIndex *pindexWalk = state->pindexLastCommonBlock; // Never fetch further than the best block we know the peer has, or more than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last // linked block we have in common with this peer. The +1 is so we can detect stalling, namely if we would be able to // download that next block if the window were 1 larger. int nWindowEnd = state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW; int nMaxHeight = std::min(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1); NodeId waitingfor = -1; while (pindexWalk->nHeight < nMaxHeight) { // Read up to 128 (or more, if more blocks than that are needed) successors of pindexWalk (towards // pindexBestKnownBlock) into vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as expensive // as iterating over ~100 CBlockIndex* entries anyway. int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight, std::max(count - vBlocks.size(), 128)); vToFetch.resize(nToFetch); pindexWalk = state->pindexBestKnownBlock->GetAncestor(pindexWalk->nHeight + nToFetch); vToFetch[nToFetch - 1] = pindexWalk; for (unsigned int i = nToFetch - 1; i > 0; i--) { vToFetch[i - 1] = vToFetch[i]->pprev; } // Iterate over those blocks in vToFetch (in forward direction), adding the ones that // are not yet downloaded and not in flight to vBlocks. In the meantime, update // pindexLastCommonBlock as long as all ancestors are already downloaded, or if it's // already part of our chain (and therefore don't need it even if pruned). for (const CBlockIndex* pindex : vToFetch) { if (!pindex->IsValid(BLOCK_VALID_TREE)) { // We consider the chain that this peer is on invalid. return; } if (!State(nodeid)->fHaveWitness && IsWitnessEnabled(pindex->pprev, consensusParams)) { // We wouldn't download this block or its descendants from this peer. return; } if (pindex->nStatus & BLOCK_HAVE_DATA || ::ChainActive().Contains(pindex)) { if (pindex->HaveTxsDownloaded()) state->pindexLastCommonBlock = pindex; } else if (mapBlocksInFlight.count(pindex->GetBlockHash()) == 0) { // The block is not already downloaded, and not yet in flight. if (pindex->nHeight > nWindowEnd) { // We reached the end of the window. if (vBlocks.size() == 0 && waitingfor != nodeid) { // We aren't able to fetch anything, but we would be if the download window was one larger. nodeStaller = waitingfor; } return; } vBlocks.push_back(pindex); if (vBlocks.size() == count) { return; } } else if (waitingfor == -1) { // This is the first already-in-flight block. waitingfor = mapBlocksInFlight[pindex->GetBlockHash()].first; } } } } } // namespace void PeerManager::PushNodeVersion(CNode& pnode, int64_t nTime) { // Note that pnode->GetLocalServices() is a reflection of the local // services we were offering when the CNode object was created for this // peer. ServiceFlags nLocalNodeServices = pnode.GetLocalServices(); uint64_t nonce = pnode.GetLocalNonce(); int nNodeStartingHeight = pnode.GetMyStartingHeight(); NodeId nodeid = pnode.GetId(); CAddress addr = pnode.addr; CAddress addrYou = addr.IsRoutable() && !IsProxy(addr) && addr.IsAddrV1Compatible() ? addr : CAddress(CService(), addr.nServices); CAddress addrMe = CAddress(CService(), nLocalNodeServices); m_connman.PushMessage(&pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERSION, PROTOCOL_VERSION, (uint64_t)nLocalNodeServices, nTime, addrYou, addrMe, nonce, strSubVersion, nNodeStartingHeight, !m_ignore_incoming_txs && pnode.m_tx_relay != nullptr)); if (fLogIPs) { LogPrint(BCLog::NET, "send version message: version %d, blocks=%d, us=%s, them=%s, peer=%d\n", PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(), addrYou.ToString(), nodeid); } else { LogPrint(BCLog::NET, "send version message: version %d, blocks=%d, us=%s, peer=%d\n", PROTOCOL_VERSION, nNodeStartingHeight, addrMe.ToString(), nodeid); } } void PeerManager::AddTxAnnouncement(const CNode& node, const GenTxid& gtxid, std::chrono::microseconds current_time) { AssertLockHeld(::cs_main); // For m_txrequest NodeId nodeid = node.GetId(); if (!node.HasPermission(PF_RELAY) && m_txrequest.Count(nodeid) >= MAX_PEER_TX_ANNOUNCEMENTS) { // Too many queued announcements from this peer return; } const CNodeState* state = State(nodeid); // Decide the TxRequestTracker parameters for this announcement: // - "preferred": if fPreferredDownload is set (= outbound, or PF_NOBAN permission) // - "reqtime": current time plus delays for: // - NONPREF_PEER_TX_DELAY for announcements from non-preferred connections // - TXID_RELAY_DELAY for txid announcements while wtxid peers are available // - OVERLOADED_PEER_TX_DELAY for announcements from peers which have at least // MAX_PEER_TX_REQUEST_IN_FLIGHT requests in flight (and don't have PF_RELAY). auto delay = std::chrono::microseconds{0}; const bool preferred = state->fPreferredDownload; if (!preferred) delay += NONPREF_PEER_TX_DELAY; if (!gtxid.IsWtxid() && g_wtxid_relay_peers > 0) delay += TXID_RELAY_DELAY; const bool overloaded = !node.HasPermission(PF_RELAY) && m_txrequest.CountInFlight(nodeid) >= MAX_PEER_TX_REQUEST_IN_FLIGHT; if (overloaded) delay += OVERLOADED_PEER_TX_DELAY; m_txrequest.ReceivedInv(nodeid, gtxid, preferred, current_time + delay); } // This function is used for testing the stale tip eviction logic, see // denialofservice_tests.cpp void UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds) { LOCK(cs_main); CNodeState *state = State(node); if (state) state->m_last_block_announcement = time_in_seconds; } void PeerManager::InitializeNode(CNode *pnode) { CAddress addr = pnode->addr; std::string addrName = pnode->GetAddrName(); NodeId nodeid = pnode->GetId(); { LOCK(cs_main); mapNodeState.emplace_hint(mapNodeState.end(), std::piecewise_construct, std::forward_as_tuple(nodeid), std::forward_as_tuple(addr, pnode->IsInboundConn())); assert(m_txrequest.Count(nodeid) == 0); } { PeerRef peer = std::make_shared(nodeid); LOCK(m_peer_mutex); m_peer_map.emplace_hint(m_peer_map.end(), nodeid, std::move(peer)); } if (!pnode->IsInboundConn()) { PushNodeVersion(*pnode, GetTime()); } } void PeerManager::ReattemptInitialBroadcast(CScheduler& scheduler) const { std::set unbroadcast_txids = m_mempool.GetUnbroadcastTxs(); for (const auto& txid : unbroadcast_txids) { CTransactionRef tx = m_mempool.get(txid); if (tx != nullptr) { LOCK(cs_main); RelayTransaction(txid, tx->GetWitnessHash(), m_connman); } else { m_mempool.RemoveUnbroadcastTx(txid, true); } } // Schedule next run for 10-15 minutes in the future. // We add randomness on every cycle to avoid the possibility of P2P fingerprinting. const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5}); scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta); } void PeerManager::FinalizeNode(const CNode& node, bool& fUpdateConnectionTime) { NodeId nodeid = node.GetId(); fUpdateConnectionTime = false; LOCK(cs_main); int misbehavior{0}; { // We remove the PeerRef from g_peer_map here, but we don't always // destruct the Peer. Sometimes another thread is still holding a // PeerRef, so the refcount is >= 1. Be careful not to do any // processing here that assumes Peer won't be changed before it's // destructed. PeerRef peer = RemovePeer(nodeid); assert(peer != nullptr); misbehavior = WITH_LOCK(peer->m_misbehavior_mutex, return peer->m_misbehavior_score); } CNodeState *state = State(nodeid); assert(state != nullptr); if (state->fSyncStarted) nSyncStarted--; if (node.fSuccessfullyConnected && misbehavior == 0 && !node.IsBlockOnlyConn() && !node.IsInboundConn()) { // Only change visible addrman state for outbound, full-relay peers fUpdateConnectionTime = true; } for (const QueuedBlock& entry : state->vBlocksInFlight) { mapBlocksInFlight.erase(entry.hash); } EraseOrphansFor(nodeid); m_txrequest.DisconnectedPeer(nodeid); nPreferredDownload -= state->fPreferredDownload; nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0); 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); if (mapNodeState.empty()) { // Do a consistency check after the last peer is removed. assert(mapBlocksInFlight.empty()); assert(nPreferredDownload == 0); assert(nPeersWithValidatedDownloads == 0); assert(g_outbound_peers_with_protect_from_disconnect == 0); assert(g_wtxid_relay_peers == 0); assert(m_txrequest.Size() == 0); } LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid); } PeerRef PeerManager::GetPeerRef(NodeId id) const { LOCK(m_peer_mutex); auto it = m_peer_map.find(id); return it != m_peer_map.end() ? it->second : nullptr; } PeerRef PeerManager::RemovePeer(NodeId id) { PeerRef ret; LOCK(m_peer_mutex); auto it = m_peer_map.find(id); if (it != m_peer_map.end()) { ret = std::move(it->second); m_peer_map.erase(it); } return ret; } bool PeerManager::GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) { { LOCK(cs_main); CNodeState* state = State(nodeid); if (state == nullptr) return false; stats.nSyncHeight = state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1; stats.nCommonHeight = state->pindexLastCommonBlock ? state->pindexLastCommonBlock->nHeight : -1; for (const QueuedBlock& queue : state->vBlocksInFlight) { if (queue.pindex) stats.vHeightInFlight.push_back(queue.pindex->nHeight); } } PeerRef peer = GetPeerRef(nodeid); if (peer == nullptr) return false; stats.m_misbehavior_score = WITH_LOCK(peer->m_misbehavior_mutex, return peer->m_misbehavior_score); return true; } ////////////////////////////////////////////////////////////////////////////// // // mapOrphanTransactions // static void AddToCompactExtraTransactions(const CTransactionRef& tx) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) { size_t max_extra_txn = gArgs.GetArg("-blockreconstructionextratxn", DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN); if (max_extra_txn <= 0) return; if (!vExtraTxnForCompact.size()) vExtraTxnForCompact.resize(max_extra_txn); vExtraTxnForCompact[vExtraTxnForCompactIt] = std::make_pair(tx->GetWitnessHash(), tx); vExtraTxnForCompactIt = (vExtraTxnForCompactIt + 1) % max_extra_txn; } bool AddOrphanTx(const CTransactionRef& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) { const uint256& hash = tx->GetHash(); if (mapOrphanTransactions.count(hash)) return false; // Ignore big transactions, to avoid a // send-big-orphans memory exhaustion attack. If a peer has a legitimate // large transaction with a missing parent then we assume // it will rebroadcast it later, after the parent transaction(s) // have been mined or received. // 100 orphans, each of which is at most 100,000 bytes big is // at most 10 megabytes of orphans and somewhat more byprev index (in the worst case): unsigned int sz = GetTransactionWeight(*tx); if (sz > MAX_STANDARD_TX_WEIGHT) { LogPrint(BCLog::MEMPOOL, "ignoring large orphan tx (size: %u, hash: %s)\n", sz, hash.ToString()); return false; } 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); } AddToCompactExtraTransactions(tx); LogPrint(BCLog::MEMPOOL, "stored orphan tx %s (mapsz %u outsz %u)\n", hash.ToString(), mapOrphanTransactions.size(), mapOrphanTransactionsByPrev.size()); return true; } int static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans) { std::map::iterator it = mapOrphanTransactions.find(hash); if (it == mapOrphanTransactions.end()) return 0; for (const CTxIn& txin : it->second.tx->vin) { auto itPrev = mapOrphanTransactionsByPrev.find(txin.prevout); if (itPrev == mapOrphanTransactionsByPrev.end()) continue; itPrev->second.erase(it); if (itPrev->second.empty()) mapOrphanTransactionsByPrev.erase(itPrev); } size_t old_pos = it->second.list_pos; assert(g_orphan_list[old_pos] == it); if (old_pos + 1 != g_orphan_list.size()) { // Unless we're deleting the last entry in g_orphan_list, move the last // entry to the position we're deleting. auto it_last = g_orphan_list.back(); g_orphan_list[old_pos] = it_last; 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; } void EraseOrphansFor(NodeId peer) { LOCK(g_cs_orphans); int nErased = 0; std::map::iterator iter = mapOrphanTransactions.begin(); while (iter != mapOrphanTransactions.end()) { std::map::iterator maybeErase = iter++; // increment to avoid iterator becoming invalid if (maybeErase->second.fromPeer == peer) { nErased += EraseOrphanTx(maybeErase->second.tx->GetHash()); } } if (nErased > 0) LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx from peer=%d\n", nErased, peer); } unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) { LOCK(g_cs_orphans); unsigned int nEvicted = 0; static int64_t nNextSweep; int64_t nNow = GetTime(); if (nNextSweep <= nNow) { // Sweep out expired orphan pool entries: int nErased = 0; int64_t nMinExpTime = nNow + ORPHAN_TX_EXPIRE_TIME - ORPHAN_TX_EXPIRE_INTERVAL; std::map::iterator iter = mapOrphanTransactions.begin(); while (iter != mapOrphanTransactions.end()) { std::map::iterator maybeErase = iter++; if (maybeErase->second.nTimeExpire <= nNow) { nErased += EraseOrphanTx(maybeErase->second.tx->GetHash()); } else { nMinExpTime = std::min(maybeErase->second.nTimeExpire, nMinExpTime); } } // Sweep again 5 minutes after the next entry that expires in order to batch the linear scan. nNextSweep = nMinExpTime + ORPHAN_TX_EXPIRE_INTERVAL; if (nErased > 0) LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx due to expiration\n", nErased); } FastRandomContext rng; while (mapOrphanTransactions.size() > nMaxOrphans) { // Evict a random orphan: size_t randompos = rng.randrange(g_orphan_list.size()); EraseOrphanTx(g_orphan_list[randompos]->first); ++nEvicted; } return nEvicted; } void PeerManager::Misbehaving(const NodeId pnode, const int howmuch, const std::string& message) { assert(howmuch > 0); PeerRef peer = GetPeerRef(pnode); if (peer == nullptr) return; LOCK(peer->m_misbehavior_mutex); peer->m_misbehavior_score += howmuch; const std::string message_prefixed = message.empty() ? "" : (": " + message); if (peer->m_misbehavior_score >= DISCOURAGEMENT_THRESHOLD && peer->m_misbehavior_score - howmuch < DISCOURAGEMENT_THRESHOLD) { LogPrint(BCLog::NET, "Misbehaving: peer=%d (%d -> %d) DISCOURAGE THRESHOLD EXCEEDED%s\n", pnode, peer->m_misbehavior_score - howmuch, peer->m_misbehavior_score, message_prefixed); peer->m_should_discourage = true; } else { LogPrint(BCLog::NET, "Misbehaving: peer=%d (%d -> %d)%s\n", pnode, peer->m_misbehavior_score - howmuch, peer->m_misbehavior_score, message_prefixed); } } bool PeerManager::MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& state, bool via_compact_block, const std::string& message) { switch (state.GetResult()) { case BlockValidationResult::BLOCK_RESULT_UNSET: break; // The node is providing invalid data: case BlockValidationResult::BLOCK_CONSENSUS: case BlockValidationResult::BLOCK_MUTATED: if (!via_compact_block) { Misbehaving(nodeid, 100, message); return true; } break; case BlockValidationResult::BLOCK_CACHED_INVALID: { LOCK(cs_main); CNodeState *node_state = State(nodeid); if (node_state == nullptr) { break; } // Discourage outbound (but not inbound) peers if on an invalid chain. // Exempt HB compact block peers. Manual connections are always protected from discouragement. if (!via_compact_block && !node_state->m_is_inbound) { Misbehaving(nodeid, 100, message); return true; } break; } case BlockValidationResult::BLOCK_INVALID_HEADER: case BlockValidationResult::BLOCK_CHECKPOINT: case BlockValidationResult::BLOCK_INVALID_PREV: Misbehaving(nodeid, 100, message); return true; // Conflicting (but not necessarily invalid) data or different policy: case BlockValidationResult::BLOCK_MISSING_PREV: // TODO: Handle this much more gracefully (10 DoS points is super arbitrary) Misbehaving(nodeid, 10, message); return true; case BlockValidationResult::BLOCK_RECENT_CONSENSUS_CHANGE: case BlockValidationResult::BLOCK_TIME_FUTURE: break; } if (message != "") { LogPrint(BCLog::NET, "peer=%d: %s\n", nodeid, message); } return false; } bool PeerManager::MaybePunishNodeForTx(NodeId nodeid, const TxValidationState& state, const std::string& message) { switch (state.GetResult()) { case TxValidationResult::TX_RESULT_UNSET: break; // The node is providing invalid data: case TxValidationResult::TX_CONSENSUS: Misbehaving(nodeid, 100, message); return true; // Conflicting (but not necessarily invalid) data or different policy: case TxValidationResult::TX_RECENT_CONSENSUS_CHANGE: case TxValidationResult::TX_INPUTS_NOT_STANDARD: case TxValidationResult::TX_NOT_STANDARD: 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; } if (message != "") { LogPrint(BCLog::NET, "peer=%d: %s\n", nodeid, message); } return false; } ////////////////////////////////////////////////////////////////////////////// // // blockchain -> download logic notification // // To prevent fingerprinting attacks, only send blocks/headers outside of the // active chain if they are no more than a month older (both in time, and in // best equivalent proof of work) than the best header chain we know about and // we fully-validated them at some point. static bool BlockRequestAllowed(const CBlockIndex* pindex, const Consensus::Params& consensusParams) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); if (::ChainActive().Contains(pindex)) return true; return pindex->IsValid(BLOCK_VALID_SCRIPTS) && (pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() < STALE_RELAY_AGE_LIMIT) && (GetBlockProofEquivalentTime(*pindexBestHeader, *pindex, *pindexBestHeader, consensusParams) < STALE_RELAY_AGE_LIMIT); } PeerManager::PeerManager(const CChainParams& chainparams, CConnman& connman, BanMan* banman, CScheduler& scheduler, ChainstateManager& chainman, CTxMemPool& pool, bool ignore_incoming_txs) : m_chainparams(chainparams), m_connman(connman), m_banman(banman), m_chainman(chainman), m_mempool(pool), m_stale_tip_check_time(0), m_ignore_incoming_txs(ignore_incoming_txs) { // Initialize global variables that cannot be constructed at startup. 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, // 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(48000, 0.000001)); // Stale tip checking and peer eviction are on two different timers, but we // don't want them to get out of sync due to drift in the scheduler, so we // combine them in one function and schedule at the quicker (peer-eviction) // timer. static_assert(EXTRA_PEER_CHECK_INTERVAL < STALE_CHECK_INTERVAL, "peer eviction timer should be less than stale tip check timer"); scheduler.scheduleEvery([this] { this->CheckForStaleTipAndEvictPeers(); }, std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL}); // schedule next run for 10-15 minutes in the future const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5}); scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta); } /** * Evict orphan txn pool entries (EraseOrphanTx) based on a newly connected * block, remember the recently confirmed transactions, and delete tracked * announcements for them. Also save the time of the last tip update. */ void PeerManager::BlockConnected(const std::shared_ptr& pblock, const CBlockIndex* pindex) { { LOCK(g_cs_orphans); std::vector vOrphanErase; for (const CTransactionRef& ptx : pblock->vtx) { const CTransaction& tx = *ptx; // Which orphan pool entries must we evict? for (const auto& txin : tx.vin) { auto itByPrev = mapOrphanTransactionsByPrev.find(txin.prevout); if (itByPrev == mapOrphanTransactionsByPrev.end()) continue; for (auto mi = itByPrev->second.begin(); mi != itByPrev->second.end(); ++mi) { const CTransaction& orphanTx = *(*mi)->second.tx; const uint256& orphanHash = orphanTx.GetHash(); vOrphanErase.push_back(orphanHash); } } } // Erase orphan transactions included or precluded by this block if (vOrphanErase.size()) { int nErased = 0; for (const uint256& orphanHash : vOrphanErase) { nErased += EraseOrphanTx(orphanHash); } LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx included or conflicted by block\n", nErased); } g_last_tip_update = GetTime(); } { 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()); } } } { LOCK(cs_main); for (const auto& ptx : pblock->vtx) { m_txrequest.ForgetTxHash(ptx->GetHash()); m_txrequest.ForgetTxHash(ptx->GetWitnessHash()); } } } void PeerManager::BlockDisconnected(const std::shared_ptr &block, const CBlockIndex* pindex) { // To avoid relay problems with transactions that were previously // confirmed, clear our filter of recently confirmed transactions whenever // there's a reorg. // This means that in a 1-block reorg (where 1 block is disconnected and // then another block reconnected), our filter will drop to having only one // block's worth of transactions in it, but that should be fine, since // presumably the most common case of relaying a confirmed transaction // should be just after a new block containing it is found. LOCK(g_cs_recent_confirmed_transactions); g_recent_confirmed_transactions->reset(); } // All of the following cache a recent block, and are protected by cs_most_recent_block static RecursiveMutex cs_most_recent_block; static std::shared_ptr most_recent_block GUARDED_BY(cs_most_recent_block); static std::shared_ptr most_recent_compact_block GUARDED_BY(cs_most_recent_block); static uint256 most_recent_block_hash GUARDED_BY(cs_most_recent_block); static bool fWitnessesPresentInMostRecentCompactBlock GUARDED_BY(cs_most_recent_block); /** * Maintain state about the best-seen block and fast-announce a compact block * to compatible peers. */ void PeerManager::NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr& pblock) { std::shared_ptr pcmpctblock = std::make_shared (*pblock, true); const CNetMsgMaker msgMaker(PROTOCOL_VERSION); LOCK(cs_main); static int nHighestFastAnnounce = 0; if (pindex->nHeight <= nHighestFastAnnounce) return; nHighestFastAnnounce = pindex->nHeight; bool fWitnessEnabled = IsWitnessEnabled(pindex->pprev, m_chainparams.GetConsensus()); uint256 hashBlock(pblock->GetHash()); { LOCK(cs_most_recent_block); most_recent_block_hash = hashBlock; most_recent_block = pblock; most_recent_compact_block = pcmpctblock; fWitnessesPresentInMostRecentCompactBlock = fWitnessEnabled; } m_connman.ForEachNode([this, &pcmpctblock, pindex, &msgMaker, fWitnessEnabled, &hashBlock](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // TODO: Avoid the repeated-serialization here if (pnode->GetCommonVersion() < INVALID_CB_NO_BAN_VERSION || pnode->fDisconnect) return; ProcessBlockAvailability(pnode->GetId()); CNodeState &state = *State(pnode->GetId()); // If the peer has, or we announced to them the previous block already, // but we don't think they have this one, go ahead and announce it if (state.fPreferHeaderAndIDs && (!fWitnessEnabled || state.fWantsCmpctWitness) && !PeerHasHeader(&state, pindex) && PeerHasHeader(&state, pindex->pprev)) { LogPrint(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n", "PeerManager::NewPoWValidBlock", hashBlock.ToString(), pnode->GetId()); m_connman.PushMessage(pnode, msgMaker.Make(NetMsgType::CMPCTBLOCK, *pcmpctblock)); state.pindexBestHeaderSent = pindex; } }); } /** * Update our best height and announce any block hashes which weren't previously * in ::ChainActive() to our peers. */ void PeerManager::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) { m_connman.SetBestHeight(pindexNew->nHeight); SetServiceFlagsIBDCache(!fInitialDownload); // Don't relay inventory during initial block download. if (fInitialDownload) return; // Find the hashes of all blocks that weren't previously in the best chain. std::vector vHashes; const CBlockIndex *pindexToAnnounce = pindexNew; while (pindexToAnnounce != pindexFork) { vHashes.push_back(pindexToAnnounce->GetBlockHash()); pindexToAnnounce = pindexToAnnounce->pprev; if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) { // Limit announcements in case of a huge reorganization. // Rely on the peer's synchronization mechanism in that case. break; } } // Relay to all peers m_connman.ForEachNode([&vHashes](CNode* pnode) { LOCK(pnode->cs_inventory); for (const uint256& hash : reverse_iterate(vHashes)) { pnode->vBlockHashesToAnnounce.push_back(hash); } }); m_connman.WakeMessageHandler(); } /** * Handle invalid block rejection and consequent peer discouragement, maintain which * peers announce compact blocks. */ void PeerManager::BlockChecked(const CBlock& block, const BlockValidationState& state) { LOCK(cs_main); const uint256 hash(block.GetHash()); std::map>::iterator it = mapBlockSource.find(hash); // If the block failed validation, we know where it came from and we're still connected // to that peer, maybe punish. if (state.IsInvalid() && it != mapBlockSource.end() && State(it->second.first)) { MaybePunishNodeForBlock(/*nodeid=*/ it->second.first, state, /*via_compact_block=*/ !it->second.second); } // Check that: // 1. The block is valid // 2. We're not in initial block download // 3. This is currently the best block we're aware of. We haven't updated // the tip yet so we have no way to check this directly here. Instead we // just check that there are currently no other blocks in flight. else if (state.IsValid() && !::ChainstateActive().IsInitialBlockDownload() && mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) { if (it != mapBlockSource.end()) { MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, m_connman); } } if (it != mapBlockSource.end()) mapBlockSource.erase(it); } ////////////////////////////////////////////////////////////////////////////// // // Messages // bool static AlreadyHaveTx(const GenTxid& gtxid, const CTxMemPool& mempool) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { assert(recentRejects); if (::ChainActive().Tip()->GetBlockHash() != hashRecentRejectsChainTip) { // If the chain tip has changed previously rejected transactions // might be now valid, e.g. due to a nLockTime'd tx becoming valid, // or a double-spend. Reset the rejects filter and give those // txs a second chance. hashRecentRejectsChainTip = ::ChainActive().Tip()->GetBlockHash(); recentRejects->reset(); } const uint256& hash = gtxid.GetHash(); { LOCK(g_cs_orphans); if (!gtxid.IsWtxid() && mapOrphanTransactions.count(hash)) { return true; } else if (gtxid.IsWtxid() && g_orphans_by_wtxid.count(hash)) { return true; } } { LOCK(g_cs_recent_confirmed_transactions); if (g_recent_confirmed_transactions->contains(hash)) return true; } return recentRejects->contains(hash) || mempool.exists(gtxid); } bool static AlreadyHaveBlock(const uint256& block_hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return LookupBlockIndex(block_hash) != nullptr; } void RelayTransaction(const uint256& txid, const uint256& wtxid, const CConnman& connman) { connman.ForEachNode([&txid, &wtxid](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); CNodeState* state = State(pnode->GetId()); if (state == nullptr) return; if (state->m_wtxid_relay) { pnode->PushTxInventory(wtxid); } else { pnode->PushTxInventory(txid); } }); } /** * Relay (gossip) an address to a few randomly chosen nodes. * We choose the same nodes within a given 24h window (if the list of connected * nodes does not change) and we don't relay to nodes that already know an * address. So within 24h we will likely relay a given address once. This is to * prevent a peer from unjustly giving their address better propagation by sending * it to us repeatedly. * @param[in] originator The peer that sent us the address. We don't want to relay it back. * @param[in] addr Address to relay. * @param[in] fReachable Whether the address' network is reachable. We relay unreachable * addresses less. * @param[in] connman Connection manager to choose nodes to relay to. */ static void RelayAddress(const CNode& originator, const CAddress& addr, bool fReachable, const CConnman& connman) { if (!fReachable && !addr.IsRelayable()) return; // Relay to a limited number of other nodes // Use deterministic randomness to send to the same nodes for 24 hours // at a time so the m_addr_knowns of the chosen nodes prevent repeats uint64_t hashAddr = addr.GetHash(); const CSipHasher hasher = connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY).Write(hashAddr << 32).Write((GetTime() + hashAddr) / (24 * 60 * 60)); FastRandomContext insecure_rand; // Relay reachable addresses to 2 peers. Unreachable addresses are relayed randomly to 1 or 2 peers. unsigned int nRelayNodes = (fReachable || (hasher.Finalize() & 1)) ? 2 : 1; std::array,2> best{{{0, nullptr}, {0, nullptr}}}; assert(nRelayNodes <= best.size()); auto sortfunc = [&best, &hasher, nRelayNodes, &originator, &addr](CNode* pnode) { if (pnode->RelayAddrsWithConn() && pnode != &originator && pnode->IsAddrCompatible(addr)) { uint64_t hashKey = CSipHasher(hasher).Write(pnode->GetId()).Finalize(); for (unsigned int i = 0; i < nRelayNodes; i++) { if (hashKey > best[i].first) { std::copy(best.begin() + i, best.begin() + nRelayNodes - 1, best.begin() + i + 1); best[i] = std::make_pair(hashKey, pnode); break; } } } }; auto pushfunc = [&addr, &best, nRelayNodes, &insecure_rand] { for (unsigned int i = 0; i < nRelayNodes && best[i].first != 0; i++) { best[i].second->PushAddress(addr, insecure_rand); } }; connman.ForEachNodeThen(std::move(sortfunc), std::move(pushfunc)); } void static ProcessGetBlockData(CNode& pfrom, const CChainParams& chainparams, const CInv& inv, CConnman& connman) { bool send = false; std::shared_ptr a_recent_block; std::shared_ptr a_recent_compact_block; bool fWitnessesPresentInARecentCompactBlock; const Consensus::Params& consensusParams = chainparams.GetConsensus(); { LOCK(cs_most_recent_block); a_recent_block = most_recent_block; a_recent_compact_block = most_recent_compact_block; fWitnessesPresentInARecentCompactBlock = fWitnessesPresentInMostRecentCompactBlock; } bool need_activate_chain = false; { LOCK(cs_main); const CBlockIndex* pindex = LookupBlockIndex(inv.hash); if (pindex) { if (pindex->HaveTxsDownloaded() && !pindex->IsValid(BLOCK_VALID_SCRIPTS) && pindex->IsValid(BLOCK_VALID_TREE)) { // If we have the block and all of its parents, but have not yet validated it, // we might be in the middle of connecting it (ie in the unlock of cs_main // before ActivateBestChain but after AcceptBlock). // In this case, we need to run ActivateBestChain prior to checking the relay // conditions below. need_activate_chain = true; } } } // release cs_main before calling ActivateBestChain if (need_activate_chain) { BlockValidationState state; if (!ActivateBestChain(state, chainparams, a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", state.ToString()); } } LOCK(cs_main); const CBlockIndex* pindex = LookupBlockIndex(inv.hash); if (pindex) { send = BlockRequestAllowed(pindex, consensusParams); if (!send) { LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom.GetId()); } } const CNetMsgMaker msgMaker(pfrom.GetCommonVersion()); // disconnect node in case we have reached the outbound limit for serving historical blocks if (send && connman.OutboundTargetReached(true) && (((pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.IsMsgFilteredBlk()) && !pfrom.HasPermission(PF_DOWNLOAD) // nodes with the download permission may exceed target ) { LogPrint(BCLog::NET, "historical block serving limit reached, disconnect peer=%d\n", pfrom.GetId()); //disconnect node pfrom.fDisconnect = true; send = false; } // Avoid leaking prune-height by never sending blocks below the NODE_NETWORK_LIMITED threshold if (send && !pfrom.HasPermission(PF_NOBAN) && ( (((pfrom.GetLocalServices() & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((pfrom.GetLocalServices() & NODE_NETWORK) != NODE_NETWORK) && (::ChainActive().Tip()->nHeight - pindex->nHeight > (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2 /* add two blocks buffer extension for possible races */) ) )) { LogPrint(BCLog::NET, "Ignore block request below NODE_NETWORK_LIMITED threshold from peer=%d\n", pfrom.GetId()); //disconnect node and prevent it from stalling (would otherwise wait for the missing block) pfrom.fDisconnect = true; send = false; } // Pruned nodes may have deleted the block, so check whether // it's available before trying to send. if (send && (pindex->nStatus & BLOCK_HAVE_DATA)) { std::shared_ptr pblock; if (a_recent_block && a_recent_block->GetHash() == pindex->GetBlockHash()) { pblock = a_recent_block; } else if (inv.IsMsgWitnessBlk()) { // Fast-path: in this case it is possible to serve the block directly from disk, // as the network format matches the format on disk std::vector block_data; if (!ReadRawBlockFromDisk(block_data, pindex, chainparams.MessageStart())) { assert(!"cannot load block from disk"); } connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::BLOCK, MakeSpan(block_data))); // Don't set pblock as we've sent the block } else { // Send block from disk std::shared_ptr pblockRead = std::make_shared(); if (!ReadBlockFromDisk(*pblockRead, pindex, consensusParams)) assert(!"cannot load block from disk"); pblock = pblockRead; } if (pblock) { if (inv.IsMsgBlk()) { connman.PushMessage(&pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, *pblock)); } else if (inv.IsMsgWitnessBlk()) { connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::BLOCK, *pblock)); } else if (inv.IsMsgFilteredBlk()) { bool sendMerkleBlock = false; CMerkleBlock merkleBlock; if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_filter); if (pfrom.m_tx_relay->pfilter) { sendMerkleBlock = true; merkleBlock = CMerkleBlock(*pblock, *pfrom.m_tx_relay->pfilter); } } if (sendMerkleBlock) { connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::MERKLEBLOCK, merkleBlock)); // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see // This avoids hurting performance by pointlessly requiring a round-trip // Note that there is currently no way for a node to request any single transactions we didn't send here - // they must either disconnect and retry or request the full block. // Thus, the protocol spec specified allows for us to provide duplicate txn here, // however we MUST always provide at least what the remote peer needs typedef std::pair PairType; for (PairType& pair : merkleBlock.vMatchedTxn) connman.PushMessage(&pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::TX, *pblock->vtx[pair.first])); } // else // no response } else if (inv.IsMsgCmpctBlk()) { // If a peer is asking for old blocks, we're almost guaranteed // they won't have a useful mempool to match against a compact block, // and we don't feel like constructing the object for them, so // instead we respond with the full, non-compact block. bool fPeerWantsWitness = State(pfrom.GetId())->fWantsCmpctWitness; int nSendFlags = fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS; if (CanDirectFetch(consensusParams) && pindex->nHeight >= ::ChainActive().Height() - MAX_CMPCTBLOCK_DEPTH) { if ((fPeerWantsWitness || !fWitnessesPresentInARecentCompactBlock) && a_recent_compact_block && a_recent_compact_block->header.GetHash() == pindex->GetBlockHash()) { connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, *a_recent_compact_block)); } else { CBlockHeaderAndShortTxIDs cmpctblock(*pblock, fPeerWantsWitness); connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock)); } } else { connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCK, *pblock)); } } } // Trigger the peer node to send a getblocks request for the next batch of inventory if (inv.hash == pfrom.hashContinue) { // Send immediately. This must send even if redundant, // and we want it right after the last block so they don't // wait for other stuff first. std::vector vInv; vInv.push_back(CInv(MSG_BLOCK, ::ChainActive().Tip()->GetBlockHash())); connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::INV, vInv)); pfrom.hashContinue.SetNull(); } } } //! Determine whether or not a peer can request a transaction, and return it (or nullptr if not found or not allowed). static CTransactionRef FindTxForGetData(const CTxMemPool& mempool, const CNode& peer, const GenTxid& gtxid, const std::chrono::seconds mempool_req, const std::chrono::seconds now) LOCKS_EXCLUDED(cs_main) { auto txinfo = mempool.info(gtxid); 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 // unconditionally. if ((mempool_req.count() && txinfo.m_time <= mempool_req) || txinfo.m_time <= now - UNCONDITIONAL_RELAY_DELAY) { return std::move(txinfo.tx); } } { LOCK(cs_main); // Otherwise, the transaction must have been announced recently. if (State(peer.GetId())->m_recently_announced_invs.contains(gtxid.GetHash())) { // 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(gtxid.GetHash()); if (mi != mapRelay.end()) return mi->second; } } return {}; } void static ProcessGetData(CNode& pfrom, Peer& peer, const CChainParams& chainparams, CConnman& connman, CTxMemPool& mempool, const std::atomic& interruptMsgProc) EXCLUSIVE_LOCKS_REQUIRED(!cs_main, peer.m_getdata_requests_mutex) { AssertLockNotHeld(cs_main); std::deque::iterator it = peer.m_getdata_requests.begin(); std::vector vNotFound; const CNetMsgMaker msgMaker(pfrom.GetCommonVersion()); const std::chrono::seconds now = GetTime(); // Get last mempool request time const std::chrono::seconds mempool_req = pfrom.m_tx_relay != nullptr ? pfrom.m_tx_relay->m_last_mempool_req.load() : std::chrono::seconds::min(); // 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 != peer.m_getdata_requests.end() && it->IsGenTxMsg()) { if (interruptMsgProc) return; // The send buffer provides backpressure. If there's no space in // the buffer, pause processing until the next call. if (pfrom.fPauseSend) break; const CInv &inv = *it++; if (pfrom.m_tx_relay == nullptr) { // Ignore GETDATA requests for transactions from blocks-only peers. continue; } CTransactionRef tx = FindTxForGetData(mempool, pfrom, ToGenTxid(inv), mempool_req, now); if (tx) { // WTX and WITNESS_TX imply we serialize with witness int nSendFlags = (inv.IsMsgTx() ? SERIALIZE_TRANSACTION_NO_WITNESS : 0); connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *tx)); mempool.RemoveUnbroadcastTx(tx->GetHash()); // As we're going to send tx, make sure its unconfirmed parents are made requestable. std::vector parent_ids_to_add; { LOCK(mempool.cs); auto txiter = mempool.GetIter(tx->GetHash()); if (txiter) { const CTxMemPoolEntry::Parents& parents = (*txiter)->GetMemPoolParentsConst(); parent_ids_to_add.reserve(parents.size()); for (const CTxMemPoolEntry& parent : parents) { if (parent.GetTime() > now - UNCONDITIONAL_RELAY_DELAY) { parent_ids_to_add.push_back(parent.GetTx().GetHash()); } } } } for (const uint256& parent_txid : parent_ids_to_add) { // Relaying a transaction with a recent but unconfirmed parent. if (WITH_LOCK(pfrom.m_tx_relay->cs_tx_inventory, return !pfrom.m_tx_relay->filterInventoryKnown.contains(parent_txid))) { LOCK(cs_main); State(pfrom.GetId())->m_recently_announced_invs.insert(parent_txid); } } } else { vNotFound.push_back(inv); } } // Only process one BLOCK item per call, since they're uncommon and can be // expensive to process. if (it != peer.m_getdata_requests.end() && !pfrom.fPauseSend) { const CInv &inv = *it++; if (inv.IsGenBlkMsg()) { ProcessGetBlockData(pfrom, chainparams, inv, connman); } // else: If the first item on the queue is an unknown type, we erase it // and continue processing the queue on the next call. } peer.m_getdata_requests.erase(peer.m_getdata_requests.begin(), it); if (!vNotFound.empty()) { // Let the peer know that we didn't find what it asked for, so it doesn't // have to wait around forever. // SPV clients care about this message: it's needed when they are // recursively walking the dependencies of relevant unconfirmed // transactions. SPV clients want to do that because they want to know // about (and store and rebroadcast and risk analyze) the dependencies // of transactions relevant to them, without having to download the // entire memory pool. // Also, other nodes can use these messages to automatically request a // transaction from some other peer that annnounced it, and stop // waiting for us to respond. // In normal operation, we often send NOTFOUND messages for parents of // transactions that we relay; if a peer is missing a parent, they may // assume we have them and request the parents from us. connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::NOTFOUND, vNotFound)); } } static uint32_t GetFetchFlags(const CNode& pfrom) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { uint32_t nFetchFlags = 0; if ((pfrom.GetLocalServices() & NODE_WITNESS) && State(pfrom.GetId())->fHaveWitness) { nFetchFlags |= MSG_WITNESS_FLAG; } return nFetchFlags; } void PeerManager::SendBlockTransactions(CNode& pfrom, const CBlock& block, const BlockTransactionsRequest& req) { BlockTransactions resp(req); for (size_t i = 0; i < req.indexes.size(); i++) { if (req.indexes[i] >= block.vtx.size()) { Misbehaving(pfrom.GetId(), 100, "getblocktxn with out-of-bounds tx indices"); return; } resp.txn[i] = block.vtx[req.indexes[i]]; } LOCK(cs_main); const CNetMsgMaker msgMaker(pfrom.GetCommonVersion()); int nSendFlags = State(pfrom.GetId())->fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS; m_connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp)); } void PeerManager::ProcessHeadersMessage(CNode& pfrom, const std::vector& headers, bool via_compact_block) { const CNetMsgMaker msgMaker(pfrom.GetCommonVersion()); size_t nCount = headers.size(); if (nCount == 0) { // Nothing interesting. Stop asking this peers for more headers. return; } bool received_new_header = false; const CBlockIndex *pindexLast = nullptr; { LOCK(cs_main); CNodeState *nodestate = State(pfrom.GetId()); // If this looks like it could be a block announcement (nCount < // MAX_BLOCKS_TO_ANNOUNCE), use special logic for handling headers that // don't connect: // - Send a getheaders message in response to try to connect the chain. // - The peer can send up to MAX_UNCONNECTING_HEADERS in a row that // don't connect before giving DoS points // - Once a headers message is received that is valid and does connect, // nUnconnectingHeaders gets reset back to 0. if (!LookupBlockIndex(headers[0].hashPrevBlock) && nCount < MAX_BLOCKS_TO_ANNOUNCE) { nodestate->nUnconnectingHeaders++; m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), uint256())); LogPrint(BCLog::NET, "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, nUnconnectingHeaders=%d)\n", headers[0].GetHash().ToString(), headers[0].hashPrevBlock.ToString(), pindexBestHeader->nHeight, pfrom.GetId(), nodestate->nUnconnectingHeaders); // Set hashLastUnknownBlock for this peer, so that if we // eventually get the headers - even from a different peer - // we can use this peer to download. UpdateBlockAvailability(pfrom.GetId(), headers.back().GetHash()); if (nodestate->nUnconnectingHeaders % MAX_UNCONNECTING_HEADERS == 0) { Misbehaving(pfrom.GetId(), 20, strprintf("%d non-connecting headers", nodestate->nUnconnectingHeaders)); } return; } uint256 hashLastBlock; for (const CBlockHeader& header : headers) { if (!hashLastBlock.IsNull() && header.hashPrevBlock != hashLastBlock) { Misbehaving(pfrom.GetId(), 20, "non-continuous headers sequence"); return; } hashLastBlock = header.GetHash(); } // If we don't have the last header, then they'll have given us // something new (if these headers are valid). if (!LookupBlockIndex(hashLastBlock)) { received_new_header = true; } } BlockValidationState state; if (!m_chainman.ProcessNewBlockHeaders(headers, state, m_chainparams, &pindexLast)) { if (state.IsInvalid()) { MaybePunishNodeForBlock(pfrom.GetId(), state, via_compact_block, "invalid header received"); return; } } { LOCK(cs_main); CNodeState *nodestate = State(pfrom.GetId()); if (nodestate->nUnconnectingHeaders > 0) { LogPrint(BCLog::NET, "peer=%d: resetting nUnconnectingHeaders (%d -> 0)\n", pfrom.GetId(), nodestate->nUnconnectingHeaders); } nodestate->nUnconnectingHeaders = 0; assert(pindexLast); UpdateBlockAvailability(pfrom.GetId(), pindexLast->GetBlockHash()); // From here, pindexBestKnownBlock should be guaranteed to be non-null, // because it is set in UpdateBlockAvailability. Some nullptr checks // are still present, however, as belt-and-suspenders. if (received_new_header && pindexLast->nChainWork > ::ChainActive().Tip()->nChainWork) { nodestate->m_last_block_announcement = GetTime(); } if (nCount == MAX_HEADERS_RESULTS) { // Headers message had its maximum size; the peer may have more headers. // TODO: optimize: if pindexLast is an ancestor of ::ChainActive().Tip or pindexBestHeader, continue // from there instead. LogPrint(BCLog::NET, "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom.GetId(), pfrom.nStartingHeight); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexLast), uint256())); } bool fCanDirectFetch = CanDirectFetch(m_chainparams.GetConsensus()); // If this set of headers is valid and ends in a block with at least as // much work as our tip, download as much as possible. if (fCanDirectFetch && pindexLast->IsValid(BLOCK_VALID_TREE) && ::ChainActive().Tip()->nChainWork <= pindexLast->nChainWork) { std::vector vToFetch; const CBlockIndex *pindexWalk = pindexLast; // Calculate all the blocks we'd need to switch to pindexLast, up to a limit. while (pindexWalk && !::ChainActive().Contains(pindexWalk) && vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) { if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) && !mapBlocksInFlight.count(pindexWalk->GetBlockHash()) && (!IsWitnessEnabled(pindexWalk->pprev, m_chainparams.GetConsensus()) || State(pfrom.GetId())->fHaveWitness)) { // We don't have this block, and it's not yet in flight. vToFetch.push_back(pindexWalk); } pindexWalk = pindexWalk->pprev; } // If pindexWalk still isn't on our main chain, we're looking at a // very large reorg at a time we think we're close to caught up to // the main chain -- this shouldn't really happen. Bail out on the // direct fetch and rely on parallel download instead. if (!::ChainActive().Contains(pindexWalk)) { LogPrint(BCLog::NET, "Large reorg, won't direct fetch to %s (%d)\n", pindexLast->GetBlockHash().ToString(), pindexLast->nHeight); } else { std::vector vGetData; // Download as much as possible, from earliest to latest. for (const CBlockIndex *pindex : reverse_iterate(vToFetch)) { if (nodestate->nBlocksInFlight >= MAX_BLOCKS_IN_TRANSIT_PER_PEER) { // Can't download any more from this peer break; } uint32_t nFetchFlags = GetFetchFlags(pfrom); vGetData.push_back(CInv(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash())); MarkBlockAsInFlight(m_mempool, pfrom.GetId(), pindex->GetBlockHash(), pindex); LogPrint(BCLog::NET, "Requesting block %s from peer=%d\n", pindex->GetBlockHash().ToString(), pfrom.GetId()); } if (vGetData.size() > 1) { LogPrint(BCLog::NET, "Downloading blocks toward %s (%d) via headers direct fetch\n", pindexLast->GetBlockHash().ToString(), pindexLast->nHeight); } if (vGetData.size() > 0) { if (nodestate->fSupportsDesiredCmpctVersion && vGetData.size() == 1 && mapBlocksInFlight.size() == 1 && pindexLast->pprev->IsValid(BLOCK_VALID_CHAIN)) { // In any case, we want to download using a compact block, not a regular one vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash); } m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, vGetData)); } } } // If we're in IBD, we want outbound peers that will serve us a useful // chain. Disconnect peers that are on chains with insufficient work. if (::ChainstateActive().IsInitialBlockDownload() && nCount != MAX_HEADERS_RESULTS) { // When nCount < MAX_HEADERS_RESULTS, we know we have no more // headers to fetch from this peer. if (nodestate->pindexBestKnownBlock && nodestate->pindexBestKnownBlock->nChainWork < nMinimumChainWork) { // This peer has too little work on their headers chain to help // us sync -- disconnect if it is an outbound disconnection // candidate. // Note: We compare their tip to nMinimumChainWork (rather than // ::ChainActive().Tip()) because we won't start block download // until we have a headers chain that has at least // nMinimumChainWork, even if a peer has a chain past our tip, // as an anti-DoS measure. if (pfrom.IsOutboundOrBlockRelayConn()) { LogPrintf("Disconnecting outbound peer %d -- headers chain has insufficient work\n", pfrom.GetId()); pfrom.fDisconnect = true; } } } // If this is an outbound full-relay peer, check to see if we should protect // it from the bad/lagging chain logic. // Note that outbound block-relay peers are excluded from this protection, and // thus always subject to eviction under the bad/lagging chain logic. // See ChainSyncTimeoutState. if (!pfrom.fDisconnect && pfrom.IsFullOutboundConn() && nodestate->pindexBestKnownBlock != nullptr) { if (g_outbound_peers_with_protect_from_disconnect < MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT && nodestate->pindexBestKnownBlock->nChainWork >= ::ChainActive().Tip()->nChainWork && !nodestate->m_chain_sync.m_protect) { LogPrint(BCLog::NET, "Protecting outbound peer=%d from eviction\n", pfrom.GetId()); nodestate->m_chain_sync.m_protect = true; ++g_outbound_peers_with_protect_from_disconnect; } } } return; } /** * Reconsider orphan transactions after a parent has been accepted to the mempool. * * @param[in/out] orphan_work_set The set of orphan transactions to reconsider. Generally only one * orphan will be reconsidered on each call of this function. This set * may be added to if accepting an orphan causes its children to be * reconsidered. */ void PeerManager::ProcessOrphanTx(std::set& orphan_work_set) { AssertLockHeld(cs_main); AssertLockHeld(g_cs_orphans); while (!orphan_work_set.empty()) { const uint256 orphanHash = *orphan_work_set.begin(); orphan_work_set.erase(orphan_work_set.begin()); auto orphan_it = mapOrphanTransactions.find(orphanHash); if (orphan_it == mapOrphanTransactions.end()) continue; const CTransactionRef porphanTx = orphan_it->second.tx; TxValidationState state; std::list removed_txn; if (AcceptToMemoryPool(m_mempool, state, porphanTx, &removed_txn, false /* bypass_limits */)) { LogPrint(BCLog::MEMPOOL, " accepted orphan tx %s\n", orphanHash.ToString()); RelayTransaction(orphanHash, porphanTx->GetWitnessHash(), m_connman); for (unsigned int i = 0; i < porphanTx->vout.size(); i++) { auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(orphanHash, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { for (const auto& elem : it_by_prev->second) { orphan_work_set.insert(elem->first); } } } EraseOrphanTx(orphanHash); for (const CTransactionRef& removedTx : removed_txn) { AddToCompactExtraTransactions(removedTx); } break; } else if (state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) { if (state.IsInvalid()) { LogPrint(BCLog::MEMPOOL, " invalid orphan tx %s from peer=%d. %s\n", orphanHash.ToString(), orphan_it->second.fromPeer, state.ToString()); // Maybe punish peer that gave us an invalid orphan tx MaybePunishNodeForTx(orphan_it->second.fromPeer, state); } // Has inputs but not accepted to mempool // Probably non-standard or insufficient fee LogPrint(BCLog::MEMPOOL, " removed orphan tx %s\n", orphanHash.ToString()); 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(porphanTx->GetWitnessHash()); // If the transaction failed for TX_INPUTS_NOT_STANDARD, // then we know that the witness was irrelevant to the policy // failure, since this check depends only on the txid // (the scriptPubKey being spent is covered by the txid). // Add the txid to the reject filter to prevent repeated // processing of this transaction in the event that child // transactions are later received (resulting in // parent-fetching by txid via the orphan-handling logic). if (state.GetResult() == TxValidationResult::TX_INPUTS_NOT_STANDARD && porphanTx->GetWitnessHash() != porphanTx->GetHash()) { // We only add the txid if it differs from the wtxid, to // avoid wasting entries in the rolling bloom filter. recentRejects->insert(porphanTx->GetHash()); } } EraseOrphanTx(orphanHash); break; } } m_mempool.check(&::ChainstateActive().CoinsTip()); } /** * Validation logic for compact filters request handling. * * May disconnect from the peer in the case of a bad request. * * @param[in] peer The peer that we received the request from * @param[in] chain_params Chain parameters * @param[in] filter_type The filter type the request is for. Must be basic filters. * @param[in] start_height The start height for the request * @param[in] stop_hash The stop_hash for the request * @param[in] max_height_diff The maximum number of items permitted to request, as specified in BIP 157 * @param[out] stop_index The CBlockIndex for the stop_hash block, if the request can be serviced. * @param[out] filter_index The filter index, if the request can be serviced. * @return True if the request can be serviced. */ static bool PrepareBlockFilterRequest(CNode& peer, const CChainParams& chain_params, BlockFilterType filter_type, uint32_t start_height, const uint256& stop_hash, uint32_t max_height_diff, const CBlockIndex*& stop_index, BlockFilterIndex*& filter_index) { const bool supported_filter_type = (filter_type == BlockFilterType::BASIC && (peer.GetLocalServices() & NODE_COMPACT_FILTERS)); if (!supported_filter_type) { LogPrint(BCLog::NET, "peer %d requested unsupported block filter type: %d\n", peer.GetId(), static_cast(filter_type)); peer.fDisconnect = true; return false; } { LOCK(cs_main); stop_index = LookupBlockIndex(stop_hash); // Check that the stop block exists and the peer would be allowed to fetch it. if (!stop_index || !BlockRequestAllowed(stop_index, chain_params.GetConsensus())) { LogPrint(BCLog::NET, "peer %d requested invalid block hash: %s\n", peer.GetId(), stop_hash.ToString()); peer.fDisconnect = true; return false; } } uint32_t stop_height = stop_index->nHeight; if (start_height > stop_height) { LogPrint(BCLog::NET, "peer %d sent invalid getcfilters/getcfheaders with " /* Continued */ "start height %d and stop height %d\n", peer.GetId(), start_height, stop_height); peer.fDisconnect = true; return false; } if (stop_height - start_height >= max_height_diff) { LogPrint(BCLog::NET, "peer %d requested too many cfilters/cfheaders: %d / %d\n", peer.GetId(), stop_height - start_height + 1, max_height_diff); peer.fDisconnect = true; return false; } filter_index = GetBlockFilterIndex(filter_type); if (!filter_index) { LogPrint(BCLog::NET, "Filter index for supported type %s not found\n", BlockFilterTypeName(filter_type)); return false; } return true; } /** * Handle a cfilters request. * * May disconnect from the peer in the case of a bad request. * * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received * @param[in] chain_params Chain parameters * @param[in] connman Pointer to the connection manager */ static void ProcessGetCFilters(CNode& peer, CDataStream& vRecv, const CChainParams& chain_params, CConnman& connman) { uint8_t filter_type_ser; uint32_t start_height; uint256 stop_hash; vRecv >> filter_type_ser >> start_height >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(peer, chain_params, filter_type, start_height, stop_hash, MAX_GETCFILTERS_SIZE, stop_index, filter_index)) { return; } std::vector filters; if (!filter_index->LookupFilterRange(start_height, stop_index, filters)) { LogPrint(BCLog::NET, "Failed to find block filter in index: filter_type=%s, start_height=%d, stop_hash=%s\n", BlockFilterTypeName(filter_type), start_height, stop_hash.ToString()); return; } for (const auto& filter : filters) { CSerializedNetMsg msg = CNetMsgMaker(peer.GetCommonVersion()) .Make(NetMsgType::CFILTER, filter); connman.PushMessage(&peer, std::move(msg)); } } /** * Handle a cfheaders request. * * May disconnect from the peer in the case of a bad request. * * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received * @param[in] chain_params Chain parameters * @param[in] connman Pointer to the connection manager */ static void ProcessGetCFHeaders(CNode& peer, CDataStream& vRecv, const CChainParams& chain_params, CConnman& connman) { uint8_t filter_type_ser; uint32_t start_height; uint256 stop_hash; vRecv >> filter_type_ser >> start_height >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(peer, chain_params, filter_type, start_height, stop_hash, MAX_GETCFHEADERS_SIZE, stop_index, filter_index)) { return; } uint256 prev_header; if (start_height > 0) { const CBlockIndex* const prev_block = stop_index->GetAncestor(static_cast(start_height - 1)); if (!filter_index->LookupFilterHeader(prev_block, prev_header)) { LogPrint(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n", BlockFilterTypeName(filter_type), prev_block->GetBlockHash().ToString()); return; } } std::vector filter_hashes; if (!filter_index->LookupFilterHashRange(start_height, stop_index, filter_hashes)) { LogPrint(BCLog::NET, "Failed to find block filter hashes in index: filter_type=%s, start_height=%d, stop_hash=%s\n", BlockFilterTypeName(filter_type), start_height, stop_hash.ToString()); return; } CSerializedNetMsg msg = CNetMsgMaker(peer.GetCommonVersion()) .Make(NetMsgType::CFHEADERS, filter_type_ser, stop_index->GetBlockHash(), prev_header, filter_hashes); connman.PushMessage(&peer, std::move(msg)); } /** * Handle a getcfcheckpt request. * * May disconnect from the peer in the case of a bad request. * * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received * @param[in] chain_params Chain parameters * @param[in] connman Pointer to the connection manager */ static void ProcessGetCFCheckPt(CNode& peer, CDataStream& vRecv, const CChainParams& chain_params, CConnman& connman) { uint8_t filter_type_ser; uint256 stop_hash; vRecv >> filter_type_ser >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(peer, chain_params, filter_type, /*start_height=*/0, stop_hash, /*max_height_diff=*/std::numeric_limits::max(), stop_index, filter_index)) { return; } std::vector headers(stop_index->nHeight / CFCHECKPT_INTERVAL); // Populate headers. const CBlockIndex* block_index = stop_index; for (int i = headers.size() - 1; i >= 0; i--) { int height = (i + 1) * CFCHECKPT_INTERVAL; block_index = block_index->GetAncestor(height); if (!filter_index->LookupFilterHeader(block_index, headers[i])) { LogPrint(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n", BlockFilterTypeName(filter_type), block_index->GetBlockHash().ToString()); return; } } CSerializedNetMsg msg = CNetMsgMaker(peer.GetCommonVersion()) .Make(NetMsgType::CFCHECKPT, filter_type_ser, stop_index->GetBlockHash(), headers); connman.PushMessage(&peer, std::move(msg)); } void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDataStream& vRecv, const std::chrono::microseconds time_received, const std::atomic& interruptMsgProc) { LogPrint(BCLog::NET, "received: %s (%u bytes) peer=%d\n", SanitizeString(msg_type), vRecv.size(), pfrom.GetId()); if (gArgs.IsArgSet("-dropmessagestest") && GetRand(gArgs.GetArg("-dropmessagestest", 0)) == 0) { LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n"); return; } PeerRef peer = GetPeerRef(pfrom.GetId()); if (peer == nullptr) return; if (msg_type == NetMsgType::VERSION) { if (pfrom.nVersion != 0) { LogPrint(BCLog::NET, "redundant version message from peer=%d\n", pfrom.GetId()); return; } int64_t nTime; CAddress addrMe; CAddress addrFrom; uint64_t nNonce = 1; uint64_t nServiceInt; ServiceFlags nServices; int nVersion; std::string cleanSubVer; int nStartingHeight = -1; bool fRelay = true; vRecv >> nVersion >> nServiceInt >> nTime >> addrMe; nServices = ServiceFlags(nServiceInt); if (!pfrom.IsInboundConn()) { m_connman.SetServices(pfrom.addr, nServices); } if (pfrom.ExpectServicesFromConn() && !HasAllDesirableServiceFlags(nServices)) { LogPrint(BCLog::NET, "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom.GetId(), nServices, GetDesirableServiceFlags(nServices)); pfrom.fDisconnect = true; return; } if (nVersion < MIN_PEER_PROTO_VERSION) { // disconnect from peers older than this proto version LogPrint(BCLog::NET, "peer=%d using obsolete version %i; disconnecting\n", pfrom.GetId(), nVersion); pfrom.fDisconnect = true; return; } if (!vRecv.empty()) vRecv >> addrFrom >> nNonce; if (!vRecv.empty()) { std::string strSubVer; vRecv >> LIMITED_STRING(strSubVer, MAX_SUBVERSION_LENGTH); cleanSubVer = SanitizeString(strSubVer); } if (!vRecv.empty()) { vRecv >> nStartingHeight; } if (!vRecv.empty()) vRecv >> fRelay; // Disconnect if we connected to ourself if (pfrom.IsInboundConn() && !m_connman.CheckIncomingNonce(nNonce)) { LogPrintf("connected to self at %s, disconnecting\n", pfrom.addr.ToString()); pfrom.fDisconnect = true; return; } if (pfrom.IsInboundConn() && addrMe.IsRoutable()) { SeenLocal(addrMe); } // Inbound peers send us their version message when they connect. // We send our version message in response. if (pfrom.IsInboundConn()) PushNodeVersion(pfrom, GetAdjustedTime()); // Change version const int greatest_common_version = std::min(nVersion, PROTOCOL_VERSION); pfrom.SetCommonVersion(greatest_common_version); pfrom.nVersion = nVersion; const CNetMsgMaker msg_maker(greatest_common_version); if (greatest_common_version >= WTXID_RELAY_VERSION) { m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::WTXIDRELAY)); } // Signal ADDRv2 support (BIP155). if (greatest_common_version >= 70016) { // BIP155 defines addrv2 and sendaddrv2 for all protocol versions, but some // implementations reject messages they don't know. As a courtesy, don't send // it to nodes with a version before 70016, as no software is known to support // BIP155 that doesn't announce at least that protocol version number. m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::SENDADDRV2)); } m_connman.PushMessage(&pfrom, msg_maker.Make(NetMsgType::VERACK)); pfrom.nServices = nServices; pfrom.SetAddrLocal(addrMe); { LOCK(pfrom.cs_SubVer); pfrom.cleanSubVer = cleanSubVer; } pfrom.nStartingHeight = nStartingHeight; // set nodes not relaying blocks and tx and not serving (parts) of the historical blockchain as "clients" pfrom.fClient = (!(nServices & NODE_NETWORK) && !(nServices & NODE_NETWORK_LIMITED)); // set nodes not capable of serving the complete blockchain history as "limited nodes" pfrom.m_limited_node = (!(nServices & NODE_NETWORK) && (nServices & NODE_NETWORK_LIMITED)); if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_filter); pfrom.m_tx_relay->fRelayTxes = fRelay; // set to true after we get the first filter* message } if((nServices & NODE_WITNESS)) { LOCK(cs_main); State(pfrom.GetId())->fHaveWitness = true; } // Potentially mark this peer as a preferred download peer. { LOCK(cs_main); UpdatePreferredDownload(pfrom, State(pfrom.GetId())); } if (!pfrom.IsInboundConn() && !pfrom.IsBlockOnlyConn()) { // For outbound peers, we try to relay our address (so that other // nodes can try to find us more quickly, as we have no guarantee // that an outbound peer is even aware of how to reach us) and do a // one-time address fetch (to help populate/update our addrman). If // we're starting up for the first time, our addrman may be pretty // empty and no one will know who we are, so these mechanisms are // important to help us connect to the network. // // We skip this for block-relay-only peers to avoid potentially leaking // information about our block-relay-only connections via address relay. if (fListen && !::ChainstateActive().IsInitialBlockDownload()) { CAddress addr = GetLocalAddress(&pfrom.addr, pfrom.GetLocalServices()); FastRandomContext insecure_rand; if (addr.IsRoutable()) { LogPrint(BCLog::NET, "ProcessMessages: advertising address %s\n", addr.ToString()); pfrom.PushAddress(addr, insecure_rand); } else if (IsPeerAddrLocalGood(&pfrom)) { addr.SetIP(addrMe); LogPrint(BCLog::NET, "ProcessMessages: advertising address %s\n", addr.ToString()); pfrom.PushAddress(addr, insecure_rand); } } // Get recent addresses m_connman.PushMessage(&pfrom, CNetMsgMaker(greatest_common_version).Make(NetMsgType::GETADDR)); pfrom.fGetAddr = true; } if (!pfrom.IsInboundConn()) { // For non-inbound connections, we update the addrman to record // connection success so that addrman will have an up-to-date // notion of which peers are online and available. // // While we strive to not leak information about block-relay-only // connections via the addrman, not moving an address to the tried // table is also potentially detrimental because new-table entries // are subject to eviction in the event of addrman collisions. We // mitigate the information-leak by never calling // CAddrMan::Connected() on block-relay-only peers; see // FinalizeNode(). // // This moves an address from New to Tried table in Addrman, // resolves tried-table collisions, etc. m_connman.MarkAddressGood(pfrom.addr); } std::string remoteAddr; if (fLogIPs) remoteAddr = ", peeraddr=" + pfrom.addr.ToString(); LogPrint(BCLog::NET, "receive version message: %s: version %d, blocks=%d, us=%s, peer=%d%s\n", cleanSubVer, pfrom.nVersion, pfrom.nStartingHeight, addrMe.ToString(), pfrom.GetId(), remoteAddr); int64_t nTimeOffset = nTime - GetTime(); pfrom.nTimeOffset = nTimeOffset; AddTimeData(pfrom.addr, nTimeOffset); // If the peer is old enough to have the old alert system, send it the final alert. if (greatest_common_version <= 70012) { CDataStream finalAlert(ParseHex("60010000000000000000000000ffffff7f00000000ffffff7ffeffff7f01ffffff7f00000000ffffff7f00ffffff7f002f555247454e543a20416c657274206b657920636f6d70726f6d697365642c2075706772616465207265717569726564004630440220653febd6410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3abd5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fecaae66ecf689bf71b50"), SER_NETWORK, PROTOCOL_VERSION); m_connman.PushMessage(&pfrom, CNetMsgMaker(greatest_common_version).Make("alert", finalAlert)); } // Feeler connections exist only to verify if address is online. if (pfrom.IsFeelerConn()) { pfrom.fDisconnect = true; } return; } if (pfrom.nVersion == 0) { // Must have a version message before anything else LogPrint(BCLog::NET, "non-version message before version handshake. Message \"%s\" from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } // At this point, the outgoing message serialization version can't change. const CNetMsgMaker msgMaker(pfrom.GetCommonVersion()); if (msg_type == NetMsgType::VERACK) { if (pfrom.fSuccessfullyConnected) return; if (!pfrom.IsInboundConn()) { LogPrintf("New outbound peer connected: version: %d, blocks=%d, peer=%d%s (%s)\n", pfrom.nVersion.load(), pfrom.nStartingHeight, pfrom.GetId(), (fLogIPs ? strprintf(", peeraddr=%s", pfrom.addr.ToString()) : ""), pfrom.ConnectionTypeAsString()); } if (pfrom.GetCommonVersion() >= SENDHEADERS_VERSION) { // Tell our peer we prefer to receive headers rather than inv's // We send this to non-NODE NETWORK peers as well, because even // non-NODE NETWORK peers can announce blocks (such as pruning // nodes) m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDHEADERS)); } if (pfrom.GetCommonVersion() >= SHORT_IDS_BLOCKS_VERSION) { // Tell our peer we are willing to provide version 1 or 2 cmpctblocks // However, we do not request new block announcements using // cmpctblock messages. // We send this to non-NODE NETWORK peers as well, because // they may wish to request compact blocks from us bool fAnnounceUsingCMPCTBLOCK = false; uint64_t nCMPCTBLOCKVersion = 2; if (pfrom.GetLocalServices() & NODE_WITNESS) m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion)); nCMPCTBLOCKVersion = 1; m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion)); } pfrom.fSuccessfullyConnected = true; return; } if (msg_type == NetMsgType::SENDHEADERS) { LOCK(cs_main); State(pfrom.GetId())->fPreferHeaders = true; return; } if (msg_type == NetMsgType::SENDCMPCT) { bool fAnnounceUsingCMPCTBLOCK = false; uint64_t nCMPCTBLOCKVersion = 0; vRecv >> fAnnounceUsingCMPCTBLOCK >> nCMPCTBLOCKVersion; if (nCMPCTBLOCKVersion == 1 || ((pfrom.GetLocalServices() & NODE_WITNESS) && nCMPCTBLOCKVersion == 2)) { LOCK(cs_main); // fProvidesHeaderAndIDs is used to "lock in" version of compact blocks we send (fWantsCmpctWitness) if (!State(pfrom.GetId())->fProvidesHeaderAndIDs) { State(pfrom.GetId())->fProvidesHeaderAndIDs = true; State(pfrom.GetId())->fWantsCmpctWitness = nCMPCTBLOCKVersion == 2; } if (State(pfrom.GetId())->fWantsCmpctWitness == (nCMPCTBLOCKVersion == 2)) { // ignore later version announces State(pfrom.GetId())->fPreferHeaderAndIDs = fAnnounceUsingCMPCTBLOCK; // save whether peer selects us as BIP152 high-bandwidth peer // (receiving sendcmpct(1) signals high-bandwidth, sendcmpct(0) low-bandwidth) pfrom.m_bip152_highbandwidth_from = fAnnounceUsingCMPCTBLOCK; } if (!State(pfrom.GetId())->fSupportsDesiredCmpctVersion) { if (pfrom.GetLocalServices() & NODE_WITNESS) State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 2); else State(pfrom.GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 1); } } return; } // Feature negotiation of wtxidrelay must 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.GetCommonVersion() >= 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 (msg_type == NetMsgType::SENDADDRV2) { if (pfrom.fSuccessfullyConnected) { // Disconnect peers that send SENDADDRV2 message after VERACK; this // must be negotiated between VERSION and VERACK. pfrom.fDisconnect = true; return; } pfrom.m_wants_addrv2 = true; return; } if (!pfrom.fSuccessfullyConnected) { LogPrint(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } if (msg_type == NetMsgType::ADDR || msg_type == NetMsgType::ADDRV2) { int stream_version = vRecv.GetVersion(); if (msg_type == NetMsgType::ADDRV2) { // Add ADDRV2_FORMAT to the version so that the CNetAddr and CAddress // unserialize methods know that an address in v2 format is coming. stream_version |= ADDRV2_FORMAT; } OverrideStream s(&vRecv, vRecv.GetType(), stream_version); std::vector vAddr; s >> vAddr; if (!pfrom.RelayAddrsWithConn()) { return; } if (vAddr.size() > MAX_ADDR_TO_SEND) { Misbehaving(pfrom.GetId(), 20, strprintf("%s message size = %u", msg_type, vAddr.size())); return; } // Store the new addresses std::vector vAddrOk; int64_t nNow = GetAdjustedTime(); int64_t nSince = nNow - 10 * 60; for (CAddress& addr : vAddr) { if (interruptMsgProc) return; // We only bother storing full nodes, though this may include // things which we would not make an outbound connection to, in // part because we may make feeler connections to them. if (!MayHaveUsefulAddressDB(addr.nServices) && !HasAllDesirableServiceFlags(addr.nServices)) continue; if (addr.nTime <= 100000000 || addr.nTime > nNow + 10 * 60) addr.nTime = nNow - 5 * 24 * 60 * 60; pfrom.AddAddressKnown(addr); if (m_banman && (m_banman->IsDiscouraged(addr) || m_banman->IsBanned(addr))) { // Do not process banned/discouraged addresses beyond remembering we received them continue; } bool fReachable = IsReachable(addr); if (addr.nTime > nSince && !pfrom.fGetAddr && vAddr.size() <= 10 && addr.IsRoutable()) { // Relay to a limited number of other nodes RelayAddress(pfrom, addr, fReachable, m_connman); } // Do not store addresses outside our network if (fReachable) vAddrOk.push_back(addr); } m_connman.AddNewAddresses(vAddrOk, pfrom.addr, 2 * 60 * 60); if (vAddr.size() < 1000) pfrom.fGetAddr = false; if (pfrom.IsAddrFetchConn()) pfrom.fDisconnect = true; return; } if (msg_type == NetMsgType::INV) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { Misbehaving(pfrom.GetId(), 20, strprintf("inv message size = %u", vInv.size())); return; } // We won't accept tx inv's if we're in blocks-only mode, or this is a // block-relay-only peer bool fBlocksOnly = m_ignore_incoming_txs || (pfrom.m_tx_relay == nullptr); // Allow peers with relay permission to send data other than blocks in blocks only mode if (pfrom.HasPermission(PF_RELAY)) { fBlocksOnly = false; } LOCK(cs_main); const auto current_time = GetTime(); uint256* best_block{nullptr}; for (CInv& inv : vInv) { if (interruptMsgProc) return; // Ignore INVs that don't match wtxidrelay setting. // Note that orphan parent fetching always uses MSG_TX GETDATAs regardless of the wtxidrelay setting. // This is fine as no INV messages are involved in that process. if (State(pfrom.GetId())->m_wtxid_relay) { if (inv.IsMsgTx()) continue; } else { if (inv.IsMsgWtx()) continue; } if (inv.IsMsgBlk()) { const bool fAlreadyHave = AlreadyHaveBlock(inv.hash); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId()); UpdateBlockAvailability(pfrom.GetId(), inv.hash); if (!fAlreadyHave && !fImporting && !fReindex && !mapBlocksInFlight.count(inv.hash)) { // Headers-first is the primary method of announcement on // the network. If a node fell back to sending blocks by inv, // it's probably for a re-org. The final block hash // provided should be the highest, so send a getheaders and // then fetch the blocks we need to catch up. best_block = &inv.hash; } } else if (inv.IsGenTxMsg()) { const GenTxid gtxid = ToGenTxid(inv); const bool fAlreadyHave = AlreadyHaveTx(gtxid, m_mempool); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId()); 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; return; } else if (!fAlreadyHave && !m_chainman.ActiveChainstate().IsInitialBlockDownload()) { AddTxAnnouncement(pfrom, gtxid, current_time); } } else { LogPrint(BCLog::NET, "Unknown inv type \"%s\" received from peer=%d\n", inv.ToString(), pfrom.GetId()); } } if (best_block != nullptr) { m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), *best_block)); LogPrint(BCLog::NET, "getheaders (%d) %s to peer=%d\n", pindexBestHeader->nHeight, best_block->ToString(), pfrom.GetId()); } return; } if (msg_type == NetMsgType::GETDATA) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { Misbehaving(pfrom.GetId(), 20, strprintf("getdata message size = %u", vInv.size())); return; } LogPrint(BCLog::NET, "received getdata (%u invsz) peer=%d\n", vInv.size(), pfrom.GetId()); if (vInv.size() > 0) { LogPrint(BCLog::NET, "received getdata for: %s peer=%d\n", vInv[0].ToString(), pfrom.GetId()); } { LOCK(peer->m_getdata_requests_mutex); peer->m_getdata_requests.insert(peer->m_getdata_requests.end(), vInv.begin(), vInv.end()); ProcessGetData(pfrom, *peer, m_chainparams, m_connman, m_mempool, interruptMsgProc); } return; } if (msg_type == NetMsgType::GETBLOCKS) { CBlockLocator locator; uint256 hashStop; vRecv >> locator >> hashStop; if (locator.vHave.size() > MAX_LOCATOR_SZ) { LogPrint(BCLog::NET, "getblocks locator size %lld > %d, disconnect peer=%d\n", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId()); pfrom.fDisconnect = true; return; } // We might have announced the currently-being-connected tip using a // compact block, which resulted in the peer sending a getblocks // request, which we would otherwise respond to without the new block. // To avoid this situation we simply verify that we are on our best // known chain now. This is super overkill, but we handle it better // for getheaders requests, and there are no known nodes which support // compact blocks but still use getblocks to request blocks. { std::shared_ptr a_recent_block; { LOCK(cs_most_recent_block); a_recent_block = most_recent_block; } BlockValidationState state; if (!ActivateBestChain(state, m_chainparams, a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", state.ToString()); } } LOCK(cs_main); // Find the last block the caller has in the main chain const CBlockIndex* pindex = FindForkInGlobalIndex(::ChainActive(), locator); // Send the rest of the chain if (pindex) pindex = ::ChainActive().Next(pindex); int nLimit = 500; LogPrint(BCLog::NET, "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit, pfrom.GetId()); for (; pindex; pindex = ::ChainActive().Next(pindex)) { if (pindex->GetBlockHash() == hashStop) { LogPrint(BCLog::NET, " getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); break; } // If pruning, don't inv blocks unless we have on disk and are likely to still have // for some reasonable time window (1 hour) that block relay might require. const int nPrunedBlocksLikelyToHave = MIN_BLOCKS_TO_KEEP - 3600 / m_chainparams.GetConsensus().nPowTargetSpacing; if (fPruneMode && (!(pindex->nStatus & BLOCK_HAVE_DATA) || pindex->nHeight <= ::ChainActive().Tip()->nHeight - nPrunedBlocksLikelyToHave)) { LogPrint(BCLog::NET, " getblocks stopping, pruned or too old block at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); break; } WITH_LOCK(pfrom.cs_inventory, pfrom.vInventoryBlockToSend.push_back(pindex->GetBlockHash())); if (--nLimit <= 0) { // When this block is requested, we'll send an inv that'll // trigger the peer to getblocks the next batch of inventory. LogPrint(BCLog::NET, " getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); pfrom.hashContinue = pindex->GetBlockHash(); break; } } return; } if (msg_type == NetMsgType::GETBLOCKTXN) { BlockTransactionsRequest req; vRecv >> req; std::shared_ptr recent_block; { LOCK(cs_most_recent_block); if (most_recent_block_hash == req.blockhash) recent_block = most_recent_block; // Unlock cs_most_recent_block to avoid cs_main lock inversion } if (recent_block) { SendBlockTransactions(pfrom, *recent_block, req); return; } { LOCK(cs_main); const CBlockIndex* pindex = LookupBlockIndex(req.blockhash); if (!pindex || !(pindex->nStatus & BLOCK_HAVE_DATA)) { LogPrint(BCLog::NET, "Peer %d sent us a getblocktxn for a block we don't have\n", pfrom.GetId()); return; } if (pindex->nHeight >= ::ChainActive().Height() - MAX_BLOCKTXN_DEPTH) { CBlock block; bool ret = ReadBlockFromDisk(block, pindex, m_chainparams.GetConsensus()); assert(ret); SendBlockTransactions(pfrom, block, req); return; } } // If an older block is requested (should never happen in practice, // but can happen in tests) send a block response instead of a // blocktxn response. Sending a full block response instead of a // small blocktxn response is preferable in the case where a peer // might maliciously send lots of getblocktxn requests to trigger // expensive disk reads, because it will require the peer to // actually receive all the data read from disk over the network. LogPrint(BCLog::NET, "Peer %d sent us a getblocktxn for a block > %i deep\n", pfrom.GetId(), MAX_BLOCKTXN_DEPTH); CInv inv; WITH_LOCK(cs_main, inv.type = State(pfrom.GetId())->fWantsCmpctWitness ? MSG_WITNESS_BLOCK : MSG_BLOCK); inv.hash = req.blockhash; WITH_LOCK(peer->m_getdata_requests_mutex, peer->m_getdata_requests.push_back(inv)); // The message processing loop will go around again (without pausing) and we'll respond then return; } if (msg_type == NetMsgType::GETHEADERS) { CBlockLocator locator; uint256 hashStop; vRecv >> locator >> hashStop; if (locator.vHave.size() > MAX_LOCATOR_SZ) { LogPrint(BCLog::NET, "getheaders locator size %lld > %d, disconnect peer=%d\n", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId()); pfrom.fDisconnect = true; return; } LOCK(cs_main); if (::ChainstateActive().IsInitialBlockDownload() && !pfrom.HasPermission(PF_DOWNLOAD)) { LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom.GetId()); return; } CNodeState *nodestate = State(pfrom.GetId()); const CBlockIndex* pindex = nullptr; if (locator.IsNull()) { // If locator is null, return the hashStop block pindex = LookupBlockIndex(hashStop); if (!pindex) { return; } if (!BlockRequestAllowed(pindex, m_chainparams.GetConsensus())) { LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block header that isn't in the main chain\n", __func__, pfrom.GetId()); return; } } else { // Find the last block the caller has in the main chain pindex = FindForkInGlobalIndex(::ChainActive(), locator); if (pindex) pindex = ::ChainActive().Next(pindex); } // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx count at the end std::vector vHeaders; int nLimit = MAX_HEADERS_RESULTS; LogPrint(BCLog::NET, "getheaders %d to %s from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), pfrom.GetId()); for (; pindex; pindex = ::ChainActive().Next(pindex)) { vHeaders.push_back(pindex->GetBlockHeader()); if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop) break; } // pindex can be nullptr either if we sent ::ChainActive().Tip() OR // if our peer has ::ChainActive().Tip() (and thus we are sending an empty // headers message). In both cases it's safe to update // pindexBestHeaderSent to be our tip. // // It is important that we simply reset the BestHeaderSent value here, // and not max(BestHeaderSent, newHeaderSent). We might have announced // the currently-being-connected tip using a compact block, which // resulted in the peer sending a headers request, which we respond to // without the new block. By resetting the BestHeaderSent, we ensure we // will re-announce the new block via headers (or compact blocks again) // in the SendMessages logic. nodestate->pindexBestHeaderSent = pindex ? pindex : ::ChainActive().Tip(); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::HEADERS, vHeaders)); return; } if (msg_type == NetMsgType::TX) { // Stop processing the transaction early if // 1) We are in blocks only mode and peer has no relay permission // 2) This peer is a block-relay-only peer if ((m_ignore_incoming_txs && !pfrom.HasPermission(PF_RELAY)) || (pfrom.m_tx_relay == nullptr)) { LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } CTransactionRef ptx; vRecv >> ptx; const CTransaction& tx = *ptx; 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); } m_txrequest.ReceivedResponse(pfrom.GetId(), txid); if (tx.HasWitness()) m_txrequest.ReceivedResponse(pfrom.GetId(), wtxid); // We do the AlreadyHaveTx() 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 rarely contains // 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 (AlreadyHaveTx(GenTxid(/* is_wtxid=*/true, wtxid), m_mempool)) { if (pfrom.HasPermission(PF_FORCERELAY)) { // Always relay transactions received from peers with forcerelay // permission, even if they were already in the mempool, allowing // the node to function as a gateway for nodes hidden behind it. if (!m_mempool.exists(tx.GetHash())) { 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(), tx.GetWitnessHash(), m_connman); } } return; } TxValidationState state; std::list lRemovedTxn; if (AcceptToMemoryPool(m_mempool, state, ptx, &lRemovedTxn, false /* bypass_limits */)) { m_mempool.check(&::ChainstateActive().CoinsTip()); // As this version of the transaction was acceptable, we can forget about any // requests for it. m_txrequest.ForgetTxHash(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); RelayTransaction(tx.GetHash(), tx.GetWitnessHash(), m_connman); for (unsigned int i = 0; i < tx.vout.size(); i++) { auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(txid, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { for (const auto& elem : it_by_prev->second) { peer->m_orphan_work_set.insert(elem->first); } } } pfrom.nLastTXTime = GetTime(); LogPrint(BCLog::MEMPOOL, "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n", pfrom.GetId(), tx.GetHash().ToString(), m_mempool.size(), m_mempool.DynamicMemoryUsage() / 1000); for (const CTransactionRef& removedTx : lRemovedTxn) { AddToCompactExtraTransactions(removedTx); } // Recursively process any orphan transactions that depended on this one ProcessOrphanTx(peer->m_orphan_work_set); } else if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) { bool fRejectedParents = false; // It may be the case that the orphans parents have all been rejected // Deduplicate parent txids, so that we don't have to loop over // the same parent txid more than once down below. std::vector unique_parents; unique_parents.reserve(tx.vin.size()); for (const CTxIn& txin : tx.vin) { // We start with all parents, and then remove duplicates below. unique_parents.push_back(txin.prevout.hash); } std::sort(unique_parents.begin(), unique_parents.end()); unique_parents.erase(std::unique(unique_parents.begin(), unique_parents.end()), unique_parents.end()); for (const uint256& parent_txid : unique_parents) { if (recentRejects->contains(parent_txid)) { fRejectedParents = true; break; } } if (!fRejectedParents) { const auto current_time = GetTime(); for (const uint256& parent_txid : unique_parents) { // Here, we only have the txid (and not wtxid) of the // inputs, so we only request in txid mode, even for // wtxidrelay peers. // Eventually we should replace this with an improved // protocol for getting all unconfirmed parents. const GenTxid gtxid{/* is_wtxid=*/false, parent_txid}; pfrom.AddKnownTx(parent_txid); if (!AlreadyHaveTx(gtxid, m_mempool)) AddTxAnnouncement(pfrom, gtxid, current_time); } AddOrphanTx(ptx, pfrom.GetId()); // Once added to the orphan pool, a tx is considered AlreadyHave, and we shouldn't request it anymore. m_txrequest.ForgetTxHash(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); // DoS prevention: do not allow mapOrphanTransactions to grow unbounded (see CVE-2012-3789) unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, gArgs.GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS)); unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx); if (nEvicted > 0) { LogPrint(BCLog::MEMPOOL, "mapOrphan overflow, removed %u tx\n", nEvicted); } } else { 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()); m_txrequest.ForgetTxHash(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); } } else { 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.GetWitnessHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); // If the transaction failed for TX_INPUTS_NOT_STANDARD, // then we know that the witness was irrelevant to the policy // failure, since this check depends only on the txid // (the scriptPubKey being spent is covered by the txid). // Add the txid to the reject filter to prevent repeated // processing of this transaction in the event that child // transactions are later received (resulting in // parent-fetching by txid via the orphan-handling logic). if (state.GetResult() == TxValidationResult::TX_INPUTS_NOT_STANDARD && tx.GetWitnessHash() != tx.GetHash()) { recentRejects->insert(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetHash()); } if (RecursiveDynamicUsage(*ptx) < 100000) { AddToCompactExtraTransactions(ptx); } } } // If a tx has been detected by recentRejects, we will have reached // this point and the tx will have been ignored. Because we haven't run // the tx through AcceptToMemoryPool, we won't have computed a DoS // score for it or determined exactly why we consider it invalid. // // This means we won't penalize any peer subsequently relaying a DoSy // tx (even if we penalized the first peer who gave it to us) because // we have to account for recentRejects showing false positives. In // other words, we shouldn't penalize a peer if we aren't *sure* they // submitted a DoSy tx. // // Note that recentRejects doesn't just record DoSy or invalid // transactions, but any tx not accepted by the mempool, which may be // due to node policy (vs. consensus). So we can't blanket penalize a // peer simply for relaying a tx that our recentRejects has caught, // regardless of false positives. if (state.IsInvalid()) { LogPrint(BCLog::MEMPOOLREJ, "%s from peer=%d was not accepted: %s\n", tx.GetHash().ToString(), pfrom.GetId(), state.ToString()); MaybePunishNodeForTx(pfrom.GetId(), state); } return; } if (msg_type == NetMsgType::CMPCTBLOCK) { // Ignore cmpctblock received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected cmpctblock message received from peer %d\n", pfrom.GetId()); return; } CBlockHeaderAndShortTxIDs cmpctblock; vRecv >> cmpctblock; bool received_new_header = false; { LOCK(cs_main); if (!LookupBlockIndex(cmpctblock.header.hashPrevBlock)) { // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers if (!::ChainstateActive().IsInitialBlockDownload()) m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), uint256())); return; } if (!LookupBlockIndex(cmpctblock.header.GetHash())) { received_new_header = true; } } const CBlockIndex *pindex = nullptr; BlockValidationState state; if (!m_chainman.ProcessNewBlockHeaders({cmpctblock.header}, state, m_chainparams, &pindex)) { if (state.IsInvalid()) { MaybePunishNodeForBlock(pfrom.GetId(), state, /*via_compact_block*/ true, "invalid header via cmpctblock"); return; } } // When we succeed in decoding a block's txids from a cmpctblock // message we typically jump to the BLOCKTXN handling code, with a // dummy (empty) BLOCKTXN message, to re-use the logic there in // completing processing of the putative block (without cs_main). bool fProcessBLOCKTXN = false; CDataStream blockTxnMsg(SER_NETWORK, PROTOCOL_VERSION); // If we end up treating this as a plain headers message, call that as well // without cs_main. bool fRevertToHeaderProcessing = false; // Keep a CBlock for "optimistic" compactblock reconstructions (see // below) std::shared_ptr pblock = std::make_shared(); bool fBlockReconstructed = false; { LOCK2(cs_main, g_cs_orphans); // If AcceptBlockHeader returned true, it set pindex assert(pindex); UpdateBlockAvailability(pfrom.GetId(), pindex->GetBlockHash()); CNodeState *nodestate = State(pfrom.GetId()); // If this was a new header with more work than our tip, update the // peer's last block announcement time if (received_new_header && pindex->nChainWork > ::ChainActive().Tip()->nChainWork) { nodestate->m_last_block_announcement = GetTime(); } std::map::iterator> >::iterator blockInFlightIt = mapBlocksInFlight.find(pindex->GetBlockHash()); bool fAlreadyInFlight = blockInFlightIt != mapBlocksInFlight.end(); if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here return; if (pindex->nChainWork <= ::ChainActive().Tip()->nChainWork || // We know something better pindex->nTx != 0) { // We had this block at some point, but pruned it if (fAlreadyInFlight) { // We requested this block for some reason, but our mempool will probably be useless // so we just grab the block via normal getdata std::vector vInv(1); vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom), cmpctblock.header.GetHash()); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); } return; } // If we're not close to tip yet, give up and let parallel block fetch work its magic if (!fAlreadyInFlight && !CanDirectFetch(m_chainparams.GetConsensus())) return; if (IsWitnessEnabled(pindex->pprev, m_chainparams.GetConsensus()) && !nodestate->fSupportsDesiredCmpctVersion) { // Don't bother trying to process compact blocks from v1 peers // after segwit activates. return; } // We want to be a bit conservative just to be extra careful about DoS // possibilities in compact block processing... if (pindex->nHeight <= ::ChainActive().Height() + 2) { if ((!fAlreadyInFlight && nodestate->nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) || (fAlreadyInFlight && blockInFlightIt->second.first == pfrom.GetId())) { std::list::iterator* queuedBlockIt = nullptr; if (!MarkBlockAsInFlight(m_mempool, pfrom.GetId(), pindex->GetBlockHash(), pindex, &queuedBlockIt)) { if (!(*queuedBlockIt)->partialBlock) (*queuedBlockIt)->partialBlock.reset(new PartiallyDownloadedBlock(&m_mempool)); else { // The block was already in flight using compact blocks from the same peer LogPrint(BCLog::NET, "Peer sent us compact block we were already syncing!\n"); return; } } PartiallyDownloadedBlock& partialBlock = *(*queuedBlockIt)->partialBlock; ReadStatus status = partialBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status == READ_STATUS_INVALID) { MarkBlockAsReceived(pindex->GetBlockHash()); // Reset in-flight state in case Misbehaving does not result in a disconnect Misbehaving(pfrom.GetId(), 100, "invalid compact block"); return; } else if (status == READ_STATUS_FAILED) { // Duplicate txindexes, the block is now in-flight, so just request it std::vector vInv(1); vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom), cmpctblock.header.GetHash()); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); return; } BlockTransactionsRequest req; for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) { if (!partialBlock.IsTxAvailable(i)) req.indexes.push_back(i); } if (req.indexes.empty()) { // Dirty hack to jump to BLOCKTXN code (TODO: move message handling into their own functions) BlockTransactions txn; txn.blockhash = cmpctblock.header.GetHash(); blockTxnMsg << txn; fProcessBLOCKTXN = true; } else { req.blockhash = pindex->GetBlockHash(); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETBLOCKTXN, req)); } } else { // This block is either already in flight from a different // peer, or this peer has too many blocks outstanding to // download from. // Optimistically try to reconstruct anyway since we might be // able to without any round trips. PartiallyDownloadedBlock tempBlock(&m_mempool); ReadStatus status = tempBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status != READ_STATUS_OK) { // TODO: don't ignore failures return; } std::vector dummy; status = tempBlock.FillBlock(*pblock, dummy); if (status == READ_STATUS_OK) { fBlockReconstructed = true; } } } else { if (fAlreadyInFlight) { // We requested this block, but its far into the future, so our // mempool will probably be useless - request the block normally std::vector vInv(1); vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(pfrom), cmpctblock.header.GetHash()); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); return; } else { // If this was an announce-cmpctblock, we want the same treatment as a header message fRevertToHeaderProcessing = true; } } } // cs_main if (fProcessBLOCKTXN) { return ProcessMessage(pfrom, NetMsgType::BLOCKTXN, blockTxnMsg, time_received, interruptMsgProc); } if (fRevertToHeaderProcessing) { // Headers received from HB compact block peers are permitted to be // relayed before full validation (see BIP 152), so we don't want to disconnect // the peer if the header turns out to be for an invalid block. // Note that if a peer tries to build on an invalid chain, that // will be detected and the peer will be disconnected/discouraged. return ProcessHeadersMessage(pfrom, {cmpctblock.header}, /*via_compact_block=*/true); } if (fBlockReconstructed) { // If we got here, we were able to optimistically reconstruct a // block that is in flight from some other peer. { LOCK(cs_main); mapBlockSource.emplace(pblock->GetHash(), std::make_pair(pfrom.GetId(), false)); } bool fNewBlock = false; // Setting fForceProcessing to true means that we bypass some of // our anti-DoS protections in AcceptBlock, which filters // unrequested blocks that might be trying to waste our resources // (eg disk space). Because we only try to reconstruct blocks when // we're close to caught up (via the CanDirectFetch() requirement // above, combined with the behavior of not requesting blocks until // we have a chain with at least nMinimumChainWork), and we ignore // compact blocks with less work than our tip, it is safe to treat // reconstructed compact blocks as having been requested. m_chainman.ProcessNewBlock(m_chainparams, pblock, /*fForceProcessing=*/true, &fNewBlock); if (fNewBlock) { pfrom.nLastBlockTime = GetTime(); } else { LOCK(cs_main); mapBlockSource.erase(pblock->GetHash()); } LOCK(cs_main); // hold cs_main for CBlockIndex::IsValid() if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS)) { // Clear download state for this block, which is in // process from some other peer. We do this after calling // ProcessNewBlock so that a malleated cmpctblock announcement // can't be used to interfere with block relay. MarkBlockAsReceived(pblock->GetHash()); } } return; } if (msg_type == NetMsgType::BLOCKTXN) { // Ignore blocktxn received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected blocktxn message received from peer %d\n", pfrom.GetId()); return; } BlockTransactions resp; vRecv >> resp; std::shared_ptr pblock = std::make_shared(); bool fBlockRead = false; { LOCK(cs_main); std::map::iterator> >::iterator it = mapBlocksInFlight.find(resp.blockhash); if (it == mapBlocksInFlight.end() || !it->second.second->partialBlock || it->second.first != pfrom.GetId()) { LogPrint(BCLog::NET, "Peer %d sent us block transactions for block we weren't expecting\n", pfrom.GetId()); return; } PartiallyDownloadedBlock& partialBlock = *it->second.second->partialBlock; ReadStatus status = partialBlock.FillBlock(*pblock, resp.txn); if (status == READ_STATUS_INVALID) { MarkBlockAsReceived(resp.blockhash); // Reset in-flight state in case Misbehaving does not result in a disconnect Misbehaving(pfrom.GetId(), 100, "invalid compact block/non-matching block transactions"); return; } else if (status == READ_STATUS_FAILED) { // Might have collided, fall back to getdata now :( std::vector invs; invs.push_back(CInv(MSG_BLOCK | GetFetchFlags(pfrom), resp.blockhash)); m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, invs)); } else { // Block is either okay, or possibly we received // READ_STATUS_CHECKBLOCK_FAILED. // Note that CheckBlock can only fail for one of a few reasons: // 1. bad-proof-of-work (impossible here, because we've already // accepted the header) // 2. merkleroot doesn't match the transactions given (already // caught in FillBlock with READ_STATUS_FAILED, so // impossible here) // 3. the block is otherwise invalid (eg invalid coinbase, // block is too big, too many legacy sigops, etc). // So if CheckBlock failed, #3 is the only possibility. // Under BIP 152, we don't discourage the peer unless proof of work is // invalid (we don't require all the stateless checks to have // been run). This is handled below, so just treat this as // though the block was successfully read, and rely on the // handling in ProcessNewBlock to ensure the block index is // updated, etc. MarkBlockAsReceived(resp.blockhash); // it is now an empty pointer fBlockRead = true; // mapBlockSource is used for potentially punishing peers and // updating which peers send us compact blocks, so the race // between here and cs_main in ProcessNewBlock is fine. // BIP 152 permits peers to relay compact blocks after validating // the header only; we should not punish peers if the block turns // out to be invalid. mapBlockSource.emplace(resp.blockhash, std::make_pair(pfrom.GetId(), false)); } } // Don't hold cs_main when we call into ProcessNewBlock if (fBlockRead) { bool fNewBlock = false; // Since we requested this block (it was in mapBlocksInFlight), force it to be processed, // even if it would not be a candidate for new tip (missing previous block, chain not long enough, etc) // This bypasses some anti-DoS logic in AcceptBlock (eg to prevent // disk-space attacks), but this should be safe due to the // protections in the compact block handler -- see related comment // in compact block optimistic reconstruction handling. m_chainman.ProcessNewBlock(m_chainparams, pblock, /*fForceProcessing=*/true, &fNewBlock); if (fNewBlock) { pfrom.nLastBlockTime = GetTime(); } else { LOCK(cs_main); mapBlockSource.erase(pblock->GetHash()); } } return; } if (msg_type == NetMsgType::HEADERS) { // Ignore headers received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected headers message received from peer %d\n", pfrom.GetId()); return; } std::vector headers; // Bypass the normal CBlock deserialization, as we don't want to risk deserializing 2000 full blocks. unsigned int nCount = ReadCompactSize(vRecv); if (nCount > MAX_HEADERS_RESULTS) { Misbehaving(pfrom.GetId(), 20, strprintf("headers message size = %u", nCount)); return; } headers.resize(nCount); for (unsigned int n = 0; n < nCount; n++) { vRecv >> headers[n]; ReadCompactSize(vRecv); // ignore tx count; assume it is 0. } return ProcessHeadersMessage(pfrom, headers, /*via_compact_block=*/false); } if (msg_type == NetMsgType::BLOCK) { // Ignore block received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected block message received from peer %d\n", pfrom.GetId()); return; } std::shared_ptr pblock = std::make_shared(); vRecv >> *pblock; LogPrint(BCLog::NET, "received block %s peer=%d\n", pblock->GetHash().ToString(), pfrom.GetId()); bool forceProcessing = false; const uint256 hash(pblock->GetHash()); { LOCK(cs_main); // Also always process if we requested the block explicitly, as we may // need it even though it is not a candidate for a new best tip. forceProcessing |= MarkBlockAsReceived(hash); // mapBlockSource is only used for punishing peers and setting // which peers send us compact blocks, so the race between here and // cs_main in ProcessNewBlock is fine. mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true)); } bool fNewBlock = false; m_chainman.ProcessNewBlock(m_chainparams, pblock, forceProcessing, &fNewBlock); if (fNewBlock) { pfrom.nLastBlockTime = GetTime(); } else { LOCK(cs_main); mapBlockSource.erase(pblock->GetHash()); } return; } if (msg_type == NetMsgType::GETADDR) { // This asymmetric behavior for inbound and outbound connections was introduced // to prevent a fingerprinting attack: an attacker can send specific fake addresses // to users' AddrMan and later request them by sending getaddr messages. // Making nodes which are behind NAT and can only make outgoing connections ignore // the getaddr message mitigates the attack. if (!pfrom.IsInboundConn()) { LogPrint(BCLog::NET, "Ignoring \"getaddr\" from %s connection. peer=%d\n", pfrom.ConnectionTypeAsString(), pfrom.GetId()); return; } // Only send one GetAddr response per connection to reduce resource waste // and discourage addr stamping of INV announcements. if (pfrom.fSentAddr) { LogPrint(BCLog::NET, "Ignoring repeated \"getaddr\". peer=%d\n", pfrom.GetId()); return; } pfrom.fSentAddr = true; pfrom.vAddrToSend.clear(); std::vector vAddr; if (pfrom.HasPermission(PF_ADDR)) { vAddr = m_connman.GetAddresses(MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND); } else { vAddr = m_connman.GetAddresses(pfrom, MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND); } FastRandomContext insecure_rand; for (const CAddress &addr : vAddr) { pfrom.PushAddress(addr, insecure_rand); } return; } if (msg_type == NetMsgType::MEMPOOL) { if (!(pfrom.GetLocalServices() & NODE_BLOOM) && !pfrom.HasPermission(PF_MEMPOOL)) { if (!pfrom.HasPermission(PF_NOBAN)) { LogPrint(BCLog::NET, "mempool request with bloom filters disabled, disconnect peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (m_connman.OutboundTargetReached(false) && !pfrom.HasPermission(PF_MEMPOOL)) { if (!pfrom.HasPermission(PF_NOBAN)) { LogPrint(BCLog::NET, "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_tx_inventory); pfrom.m_tx_relay->fSendMempool = true; } return; } if (msg_type == NetMsgType::PING) { if (pfrom.GetCommonVersion() > BIP0031_VERSION) { uint64_t nonce = 0; vRecv >> nonce; // Echo the message back with the nonce. This allows for two useful features: // // 1) A remote node can quickly check if the connection is operational // 2) Remote nodes can measure the latency of the network thread. If this node // is overloaded it won't respond to pings quickly and the remote node can // avoid sending us more work, like chain download requests. // // The nonce stops the remote getting confused between different pings: without // it, if the remote node sends a ping once per second and this node takes 5 // seconds to respond to each, the 5th ping the remote sends would appear to // return very quickly. m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::PONG, nonce)); } return; } if (msg_type == NetMsgType::PONG) { const auto ping_end = time_received; uint64_t nonce = 0; size_t nAvail = vRecv.in_avail(); bool bPingFinished = false; std::string sProblem; if (nAvail >= sizeof(nonce)) { vRecv >> nonce; // Only process pong message if there is an outstanding ping (old ping without nonce should never pong) if (pfrom.nPingNonceSent != 0) { if (nonce == pfrom.nPingNonceSent) { // Matching pong received, this ping is no longer outstanding bPingFinished = true; const auto ping_time = ping_end - pfrom.m_ping_start.load(); if (ping_time.count() >= 0) { // Successful ping time measurement, replace previous pfrom.nPingUsecTime = count_microseconds(ping_time); pfrom.nMinPingUsecTime = std::min(pfrom.nMinPingUsecTime.load(), count_microseconds(ping_time)); } else { // This should never happen sProblem = "Timing mishap"; } } else { // Nonce mismatches are normal when pings are overlapping sProblem = "Nonce mismatch"; if (nonce == 0) { // This is most likely a bug in another implementation somewhere; cancel this ping bPingFinished = true; sProblem = "Nonce zero"; } } } else { sProblem = "Unsolicited pong without ping"; } } else { // This is most likely a bug in another implementation somewhere; cancel this ping bPingFinished = true; sProblem = "Short payload"; } if (!(sProblem.empty())) { LogPrint(BCLog::NET, "pong peer=%d: %s, %x expected, %x received, %u bytes\n", pfrom.GetId(), sProblem, pfrom.nPingNonceSent, nonce, nAvail); } if (bPingFinished) { pfrom.nPingNonceSent = 0; } return; } if (msg_type == NetMsgType::FILTERLOAD) { if (!(pfrom.GetLocalServices() & NODE_BLOOM)) { pfrom.fDisconnect = true; return; } CBloomFilter filter; vRecv >> filter; if (!filter.IsWithinSizeConstraints()) { // There is no excuse for sending a too-large filter Misbehaving(pfrom.GetId(), 100, "too-large bloom filter"); } else if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_filter); pfrom.m_tx_relay->pfilter.reset(new CBloomFilter(filter)); pfrom.m_tx_relay->fRelayTxes = true; } return; } if (msg_type == NetMsgType::FILTERADD) { if (!(pfrom.GetLocalServices() & NODE_BLOOM)) { pfrom.fDisconnect = true; return; } std::vector vData; vRecv >> vData; // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object, // and thus, the maximum size any matched object can have) in a filteradd message bool bad = false; if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) { bad = true; } else if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_filter); if (pfrom.m_tx_relay->pfilter) { pfrom.m_tx_relay->pfilter->insert(vData); } else { bad = true; } } if (bad) { Misbehaving(pfrom.GetId(), 100, "bad filteradd message"); } return; } if (msg_type == NetMsgType::FILTERCLEAR) { if (!(pfrom.GetLocalServices() & NODE_BLOOM)) { pfrom.fDisconnect = true; return; } if (pfrom.m_tx_relay == nullptr) { return; } LOCK(pfrom.m_tx_relay->cs_filter); pfrom.m_tx_relay->pfilter = nullptr; pfrom.m_tx_relay->fRelayTxes = true; return; } if (msg_type == NetMsgType::FEEFILTER) { CAmount newFeeFilter = 0; vRecv >> newFeeFilter; if (MoneyRange(newFeeFilter)) { if (pfrom.m_tx_relay != nullptr) { LOCK(pfrom.m_tx_relay->cs_feeFilter); pfrom.m_tx_relay->minFeeFilter = newFeeFilter; } LogPrint(BCLog::NET, "received: feefilter of %s from peer=%d\n", CFeeRate(newFeeFilter).ToString(), pfrom.GetId()); } return; } if (msg_type == NetMsgType::GETCFILTERS) { ProcessGetCFilters(pfrom, vRecv, m_chainparams, m_connman); return; } if (msg_type == NetMsgType::GETCFHEADERS) { ProcessGetCFHeaders(pfrom, vRecv, m_chainparams, m_connman); return; } if (msg_type == NetMsgType::GETCFCHECKPT) { ProcessGetCFCheckPt(pfrom, vRecv, m_chainparams, m_connman); return; } if (msg_type == NetMsgType::NOTFOUND) { std::vector vInv; vRecv >> vInv; if (vInv.size() <= MAX_PEER_TX_ANNOUNCEMENTS + MAX_BLOCKS_IN_TRANSIT_PER_PEER) { LOCK(::cs_main); for (CInv &inv : vInv) { if (inv.IsGenTxMsg()) { // If we receive a NOTFOUND message for a tx we requested, mark the announcement for it as // completed in TxRequestTracker. m_txrequest.ReceivedResponse(pfrom.GetId(), inv.hash); } } } return; } // Ignore unknown commands for extensibility LogPrint(BCLog::NET, "Unknown command \"%s\" from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } bool PeerManager::MaybeDiscourageAndDisconnect(CNode& pnode) { const NodeId peer_id{pnode.GetId()}; PeerRef peer = GetPeerRef(peer_id); if (peer == nullptr) return false; { LOCK(peer->m_misbehavior_mutex); // There's nothing to do if the m_should_discourage flag isn't set if (!peer->m_should_discourage) return false; peer->m_should_discourage = false; } // peer.m_misbehavior_mutex if (pnode.HasPermission(PF_NOBAN)) { // We never disconnect or discourage peers for bad behavior if they have the NOBAN permission flag LogPrintf("Warning: not punishing noban peer %d!\n", peer_id); return false; } if (pnode.IsManualConn()) { // We never disconnect or discourage manual peers for bad behavior LogPrintf("Warning: not punishing manually connected peer %d!\n", peer_id); return false; } if (pnode.addr.IsLocal()) { // We disconnect local peers for bad behavior but don't discourage (since that would discourage // all peers on the same local address) LogPrintf("Warning: disconnecting but not discouraging local peer %d!\n", peer_id); pnode.fDisconnect = true; return true; } // Normal case: Disconnect the peer and discourage all nodes sharing the address LogPrint(BCLog::NET, "Disconnecting and discouraging peer %d!\n", peer_id); if (m_banman) m_banman->Discourage(pnode.addr); m_connman.DisconnectNode(pnode.addr); return true; } bool PeerManager::ProcessMessages(CNode* pfrom, std::atomic& interruptMsgProc) { bool fMoreWork = false; PeerRef peer = GetPeerRef(pfrom->GetId()); if (peer == nullptr) return false; { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) { ProcessGetData(*pfrom, *peer, m_chainparams, m_connman, m_mempool, interruptMsgProc); } } { LOCK2(cs_main, g_cs_orphans); if (!peer->m_orphan_work_set.empty()) { ProcessOrphanTx(peer->m_orphan_work_set); } } if (pfrom->fDisconnect) return false; // this maintains the order of responses // and prevents m_getdata_requests to grow unbounded { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) return true; } { LOCK(g_cs_orphans); if (!peer->m_orphan_work_set.empty()) return true; } // Don't bother if send buffer is too full to respond anyway if (pfrom->fPauseSend) return false; std::list msgs; { LOCK(pfrom->cs_vProcessMsg); if (pfrom->vProcessMsg.empty()) return false; // Just take one message msgs.splice(msgs.begin(), pfrom->vProcessMsg, pfrom->vProcessMsg.begin()); pfrom->nProcessQueueSize -= msgs.front().m_raw_message_size; pfrom->fPauseRecv = pfrom->nProcessQueueSize > m_connman.GetReceiveFloodSize(); fMoreWork = !pfrom->vProcessMsg.empty(); } CNetMessage& msg(msgs.front()); msg.SetVersion(pfrom->GetCommonVersion()); const std::string& msg_type = msg.m_command; // Message size unsigned int nMessageSize = msg.m_message_size; try { ProcessMessage(*pfrom, msg_type, msg.m_recv, msg.m_time, interruptMsgProc); if (interruptMsgProc) return false; { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) fMoreWork = true; } } catch (const std::exception& e) { LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' (%s) caught\n", __func__, SanitizeString(msg_type), nMessageSize, e.what(), typeid(e).name()); } catch (...) { LogPrint(BCLog::NET, "%s(%s, %u bytes): Unknown exception caught\n", __func__, SanitizeString(msg_type), nMessageSize); } return fMoreWork; } void PeerManager::ConsiderEviction(CNode& pto, int64_t time_in_seconds) { AssertLockHeld(cs_main); CNodeState &state = *State(pto.GetId()); const CNetMsgMaker msgMaker(pto.GetCommonVersion()); if (!state.m_chain_sync.m_protect && pto.IsOutboundOrBlockRelayConn() && state.fSyncStarted) { // This is an outbound peer subject to disconnection if they don't // announce a block with as much work as the current tip within // CHAIN_SYNC_TIMEOUT + HEADERS_RESPONSE_TIME seconds (note: if // their chain has more work than ours, we should sync to it, // unless it's invalid, in which case we should find that out and // disconnect from them elsewhere). if (state.pindexBestKnownBlock != nullptr && state.pindexBestKnownBlock->nChainWork >= ::ChainActive().Tip()->nChainWork) { if (state.m_chain_sync.m_timeout != 0) { state.m_chain_sync.m_timeout = 0; state.m_chain_sync.m_work_header = nullptr; state.m_chain_sync.m_sent_getheaders = false; } } else if (state.m_chain_sync.m_timeout == 0 || (state.m_chain_sync.m_work_header != nullptr && state.pindexBestKnownBlock != nullptr && state.pindexBestKnownBlock->nChainWork >= state.m_chain_sync.m_work_header->nChainWork)) { // Our best block known by this peer is behind our tip, and we're either noticing // that for the first time, OR this peer was able to catch up to some earlier point // where we checked against our tip. // Either way, set a new timeout based on current tip. state.m_chain_sync.m_timeout = time_in_seconds + CHAIN_SYNC_TIMEOUT; state.m_chain_sync.m_work_header = ::ChainActive().Tip(); state.m_chain_sync.m_sent_getheaders = false; } else if (state.m_chain_sync.m_timeout > 0 && time_in_seconds > state.m_chain_sync.m_timeout) { // No evidence yet that our peer has synced to a chain with work equal to that // of our tip, when we first detected it was behind. Send a single getheaders // message to give the peer a chance to update us. if (state.m_chain_sync.m_sent_getheaders) { // They've run out of time to catch up! LogPrintf("Disconnecting outbound peer %d for old chain, best known block = %s\n", pto.GetId(), state.pindexBestKnownBlock != nullptr ? state.pindexBestKnownBlock->GetBlockHash().ToString() : ""); pto.fDisconnect = true; } else { assert(state.m_chain_sync.m_work_header); LogPrint(BCLog::NET, "sending getheaders to outbound peer=%d to verify chain work (current best known block:%s, benchmark blockhash: %s)\n", pto.GetId(), state.pindexBestKnownBlock != nullptr ? state.pindexBestKnownBlock->GetBlockHash().ToString() : "", state.m_chain_sync.m_work_header->GetBlockHash().ToString()); m_connman.PushMessage(&pto, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(state.m_chain_sync.m_work_header->pprev), uint256())); state.m_chain_sync.m_sent_getheaders = true; constexpr int64_t HEADERS_RESPONSE_TIME = 120; // 2 minutes // Bump the timeout to allow a response, which could clear the timeout // (if the response shows the peer has synced), reset the timeout (if // the peer syncs to the required work but not to our tip), or result // in disconnect (if we advance to the timeout and pindexBestKnownBlock // has not sufficiently progressed) state.m_chain_sync.m_timeout = time_in_seconds + HEADERS_RESPONSE_TIME; } } } } void PeerManager::EvictExtraOutboundPeers(int64_t time_in_seconds) { // If we have any extra block-relay-only peers, disconnect the youngest unless // it's given us a block -- in which case, compare with the second-youngest, and // out of those two, disconnect the peer who least recently gave us a block. // The youngest block-relay-only peer would be the extra peer we connected // to temporarily in order to sync our tip; see net.cpp. // Note that we use higher nodeid as a measure for most recent connection. if (m_connman.GetExtraBlockRelayCount() > 0) { std::pair youngest_peer{-1, 0}, next_youngest_peer{-1, 0}; m_connman.ForEachNode([&](CNode* pnode) { if (!pnode->IsBlockOnlyConn() || pnode->fDisconnect) return; if (pnode->GetId() > youngest_peer.first) { next_youngest_peer = youngest_peer; youngest_peer.first = pnode->GetId(); youngest_peer.second = pnode->nLastBlockTime; } }); NodeId to_disconnect = youngest_peer.first; if (youngest_peer.second > next_youngest_peer.second) { // Our newest block-relay-only peer gave us a block more recently; // disconnect our second youngest. to_disconnect = next_youngest_peer.first; } m_connman.ForNode(to_disconnect, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // Make sure we're not getting a block right now, and that // we've been connected long enough for this eviction to happen // at all. // Note that we only request blocks from a peer if we learn of a // valid headers chain with at least as much work as our tip. CNodeState *node_state = State(pnode->GetId()); if (node_state == nullptr || (time_in_seconds - pnode->nTimeConnected >= MINIMUM_CONNECT_TIME && node_state->nBlocksInFlight == 0)) { pnode->fDisconnect = true; LogPrint(BCLog::NET, "disconnecting extra block-relay-only peer=%d (last block received at time %d)\n", pnode->GetId(), pnode->nLastBlockTime); return true; } else { LogPrint(BCLog::NET, "keeping block-relay-only peer=%d chosen for eviction (connect time: %d, blocks_in_flight: %d)\n", pnode->GetId(), pnode->nTimeConnected, node_state->nBlocksInFlight); } return false; }); } // Check whether we have too many outbound-full-relay peers if (m_connman.GetExtraFullOutboundCount() > 0) { // If we have more outbound-full-relay peers than we target, disconnect one. // Pick the outbound-full-relay peer that least recently announced // us a new block, with ties broken by choosing the more recent // connection (higher node id) NodeId worst_peer = -1; int64_t oldest_block_announcement = std::numeric_limits::max(); m_connman.ForEachNode([&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // Only consider outbound-full-relay peers that are not already // marked for disconnection if (!pnode->IsFullOutboundConn() || pnode->fDisconnect) return; CNodeState *state = State(pnode->GetId()); if (state == nullptr) return; // shouldn't be possible, but just in case // Don't evict our protected peers if (state->m_chain_sync.m_protect) return; if (state->m_last_block_announcement < oldest_block_announcement || (state->m_last_block_announcement == oldest_block_announcement && pnode->GetId() > worst_peer)) { worst_peer = pnode->GetId(); oldest_block_announcement = state->m_last_block_announcement; } }); if (worst_peer != -1) { bool disconnected = m_connman.ForNode(worst_peer, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // Only disconnect a peer that has been connected to us for // some reasonable fraction of our check-frequency, to give // it time for new information to have arrived. // Also don't disconnect any peer we're trying to download a // block from. CNodeState &state = *State(pnode->GetId()); if (time_in_seconds - pnode->nTimeConnected > MINIMUM_CONNECT_TIME && state.nBlocksInFlight == 0) { LogPrint(BCLog::NET, "disconnecting extra outbound peer=%d (last block announcement received at time %d)\n", pnode->GetId(), oldest_block_announcement); pnode->fDisconnect = true; return true; } else { LogPrint(BCLog::NET, "keeping outbound peer=%d chosen for eviction (connect time: %d, blocks_in_flight: %d)\n", pnode->GetId(), pnode->nTimeConnected, state.nBlocksInFlight); return false; } }); if (disconnected) { // If we disconnected an extra peer, that means we successfully // connected to at least one peer after the last time we // detected a stale tip. Don't try any more extra peers until // we next detect a stale tip, to limit the load we put on the // network from these extra connections. m_connman.SetTryNewOutboundPeer(false); } } } } void PeerManager::CheckForStaleTipAndEvictPeers() { LOCK(cs_main); int64_t time_in_seconds = GetTime(); EvictExtraOutboundPeers(time_in_seconds); if (time_in_seconds > m_stale_tip_check_time) { // Check whether our tip is stale, and if so, allow using an extra // outbound peer if (!fImporting && !fReindex && m_connman.GetNetworkActive() && m_connman.GetUseAddrmanOutgoing() && TipMayBeStale(m_chainparams.GetConsensus())) { LogPrintf("Potential stale tip detected, will try using extra outbound peer (last tip update: %d seconds ago)\n", time_in_seconds - g_last_tip_update); m_connman.SetTryNewOutboundPeer(true); } else if (m_connman.GetTryNewOutboundPeer()) { m_connman.SetTryNewOutboundPeer(false); } m_stale_tip_check_time = time_in_seconds + STALE_CHECK_INTERVAL; } if (!m_initial_sync_finished && CanDirectFetch(m_chainparams.GetConsensus())) { m_connman.StartExtraBlockRelayPeers(); m_initial_sync_finished = true; } } namespace { class CompareInvMempoolOrder { CTxMemPool *mp; bool m_wtxid_relay; public: explicit CompareInvMempoolOrder(CTxMemPool *_mempool, bool use_wtxid) { mp = _mempool; m_wtxid_relay = use_wtxid; } bool operator()(std::set::iterator a, std::set::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, m_wtxid_relay); } }; } bool PeerManager::SendMessages(CNode* pto) { const Consensus::Params& consensusParams = m_chainparams.GetConsensus(); // We must call MaybeDiscourageAndDisconnect first, to ensure that we'll // disconnect misbehaving peers even before the version handshake is complete. if (MaybeDiscourageAndDisconnect(*pto)) return true; // Don't send anything until the version handshake is complete if (!pto->fSuccessfullyConnected || pto->fDisconnect) return true; // If we get here, the outgoing message serialization version is set and can't change. const CNetMsgMaker msgMaker(pto->GetCommonVersion()); // // Message: ping // bool pingSend = false; if (pto->fPingQueued) { // RPC ping request by user pingSend = true; } if (pto->nPingNonceSent == 0 && pto->m_ping_start.load() + PING_INTERVAL < GetTime()) { // Ping automatically sent as a latency probe & keepalive. pingSend = true; } if (pingSend) { uint64_t nonce = 0; while (nonce == 0) { GetRandBytes((unsigned char*)&nonce, sizeof(nonce)); } pto->fPingQueued = false; pto->m_ping_start = GetTime(); if (pto->GetCommonVersion() > BIP0031_VERSION) { pto->nPingNonceSent = nonce; m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::PING, nonce)); } else { // Peer is too old to support ping command with nonce, pong will never arrive. pto->nPingNonceSent = 0; m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::PING)); } } { LOCK(cs_main); CNodeState &state = *State(pto->GetId()); // Address refresh broadcast auto current_time = GetTime(); if (pto->RelayAddrsWithConn() && !::ChainstateActive().IsInitialBlockDownload() && pto->m_next_local_addr_send < current_time) { // If we've sent before, clear the bloom filter for the peer, so that our // self-announcement will actually go out. // This might be unnecessary if the bloom filter has already rolled // over since our last self-announcement, but there is only a small // bandwidth cost that we can incur by doing this (which happens // once a day on average). if (pto->m_next_local_addr_send != 0us) { pto->m_addr_known->reset(); } AdvertiseLocal(pto); pto->m_next_local_addr_send = PoissonNextSend(current_time, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL); } // // Message: addr // if (pto->RelayAddrsWithConn() && pto->m_next_addr_send < current_time) { pto->m_next_addr_send = PoissonNextSend(current_time, AVG_ADDRESS_BROADCAST_INTERVAL); std::vector vAddr; vAddr.reserve(pto->vAddrToSend.size()); assert(pto->m_addr_known); const char* msg_type; int make_flags; if (pto->m_wants_addrv2) { msg_type = NetMsgType::ADDRV2; make_flags = ADDRV2_FORMAT; } else { msg_type = NetMsgType::ADDR; make_flags = 0; } for (const CAddress& addr : pto->vAddrToSend) { if (!pto->m_addr_known->contains(addr.GetKey())) { pto->m_addr_known->insert(addr.GetKey()); vAddr.push_back(addr); // receiver rejects addr messages larger than MAX_ADDR_TO_SEND if (vAddr.size() >= MAX_ADDR_TO_SEND) { m_connman.PushMessage(pto, msgMaker.Make(make_flags, msg_type, vAddr)); vAddr.clear(); } } } pto->vAddrToSend.clear(); if (!vAddr.empty()) m_connman.PushMessage(pto, msgMaker.Make(make_flags, msg_type, vAddr)); // we only send the big addr message once if (pto->vAddrToSend.capacity() > 40) pto->vAddrToSend.shrink_to_fit(); } // Start block sync if (pindexBestHeader == nullptr) pindexBestHeader = ::ChainActive().Tip(); bool fFetch = state.fPreferredDownload || (nPreferredDownload == 0 && !pto->fClient && !pto->IsAddrFetchConn()); // Download if this is a nice peer, or we have no nice peers and this one might do. if (!state.fSyncStarted && !pto->fClient && !fImporting && !fReindex) { // Only actively request headers from a single peer, unless we're close to today. if ((nSyncStarted == 0 && fFetch) || pindexBestHeader->GetBlockTime() > GetAdjustedTime() - 24 * 60 * 60) { state.fSyncStarted = true; state.nHeadersSyncTimeout = count_microseconds(current_time) + HEADERS_DOWNLOAD_TIMEOUT_BASE + HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER * (GetAdjustedTime() - pindexBestHeader->GetBlockTime())/(consensusParams.nPowTargetSpacing); nSyncStarted++; const CBlockIndex *pindexStart = pindexBestHeader; /* If possible, start at the block preceding the currently best known header. This ensures that we always get a non-empty list of headers back as long as the peer is up-to-date. With a non-empty response, we can initialise the peer's known best block. This wouldn't be possible if we requested starting at pindexBestHeader and got back an empty response. */ if (pindexStart->pprev) pindexStart = pindexStart->pprev; LogPrint(BCLog::NET, "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->GetId(), pto->nStartingHeight); m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexStart), uint256())); } } // // Try sending block announcements via headers // { // If we have less than MAX_BLOCKS_TO_ANNOUNCE in our // list of block hashes we're relaying, and our peer wants // headers announcements, then find the first header // not yet known to our peer but would connect, and send. // If no header would connect, or if we have too many // blocks, or if the peer doesn't want headers, just // add all to the inv queue. LOCK(pto->cs_inventory); std::vector vHeaders; bool fRevertToInv = ((!state.fPreferHeaders && (!state.fPreferHeaderAndIDs || pto->vBlockHashesToAnnounce.size() > 1)) || pto->vBlockHashesToAnnounce.size() > MAX_BLOCKS_TO_ANNOUNCE); const CBlockIndex *pBestIndex = nullptr; // last header queued for delivery ProcessBlockAvailability(pto->GetId()); // ensure pindexBestKnownBlock is up-to-date if (!fRevertToInv) { bool fFoundStartingHeader = false; // Try to find first header that our peer doesn't have, and // then send all headers past that one. If we come across any // headers that aren't on ::ChainActive(), give up. for (const uint256 &hash : pto->vBlockHashesToAnnounce) { const CBlockIndex* pindex = LookupBlockIndex(hash); assert(pindex); if (::ChainActive()[pindex->nHeight] != pindex) { // Bail out if we reorged away from this block fRevertToInv = true; break; } if (pBestIndex != nullptr && pindex->pprev != pBestIndex) { // This means that the list of blocks to announce don't // connect to each other. // This shouldn't really be possible to hit during // regular operation (because reorgs should take us to // a chain that has some block not on the prior chain, // which should be caught by the prior check), but one // way this could happen is by using invalidateblock / // reconsiderblock repeatedly on the tip, causing it to // be added multiple times to vBlockHashesToAnnounce. // Robustly deal with this rare situation by reverting // to an inv. fRevertToInv = true; break; } pBestIndex = pindex; if (fFoundStartingHeader) { // add this to the headers message vHeaders.push_back(pindex->GetBlockHeader()); } else if (PeerHasHeader(&state, pindex)) { continue; // keep looking for the first new block } else if (pindex->pprev == nullptr || PeerHasHeader(&state, pindex->pprev)) { // Peer doesn't have this header but they do have the prior one. // Start sending headers. fFoundStartingHeader = true; vHeaders.push_back(pindex->GetBlockHeader()); } else { // Peer doesn't have this header or the prior one -- nothing will // connect, so bail out. fRevertToInv = true; break; } } } if (!fRevertToInv && !vHeaders.empty()) { if (vHeaders.size() == 1 && state.fPreferHeaderAndIDs) { // We only send up to 1 block as header-and-ids, as otherwise // probably means we're doing an initial-ish-sync or they're slow LogPrint(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n", __func__, vHeaders.front().GetHash().ToString(), pto->GetId()); int nSendFlags = state.fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS; bool fGotBlockFromCache = false; { LOCK(cs_most_recent_block); if (most_recent_block_hash == pBestIndex->GetBlockHash()) { if (state.fWantsCmpctWitness || !fWitnessesPresentInMostRecentCompactBlock) m_connman.PushMessage(pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, *most_recent_compact_block)); else { CBlockHeaderAndShortTxIDs cmpctblock(*most_recent_block, state.fWantsCmpctWitness); m_connman.PushMessage(pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock)); } fGotBlockFromCache = true; } } if (!fGotBlockFromCache) { CBlock block; bool ret = ReadBlockFromDisk(block, pBestIndex, consensusParams); assert(ret); CBlockHeaderAndShortTxIDs cmpctblock(block, state.fWantsCmpctWitness); m_connman.PushMessage(pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock)); } state.pindexBestHeaderSent = pBestIndex; } else if (state.fPreferHeaders) { if (vHeaders.size() > 1) { LogPrint(BCLog::NET, "%s: %u headers, range (%s, %s), to peer=%d\n", __func__, vHeaders.size(), vHeaders.front().GetHash().ToString(), vHeaders.back().GetHash().ToString(), pto->GetId()); } else { LogPrint(BCLog::NET, "%s: sending header %s to peer=%d\n", __func__, vHeaders.front().GetHash().ToString(), pto->GetId()); } m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::HEADERS, vHeaders)); state.pindexBestHeaderSent = pBestIndex; } else fRevertToInv = true; } if (fRevertToInv) { // If falling back to using an inv, just try to inv the tip. // The last entry in vBlockHashesToAnnounce was our tip at some point // in the past. if (!pto->vBlockHashesToAnnounce.empty()) { const uint256 &hashToAnnounce = pto->vBlockHashesToAnnounce.back(); const CBlockIndex* pindex = LookupBlockIndex(hashToAnnounce); assert(pindex); // Warn if we're announcing a block that is not on the main chain. // This should be very rare and could be optimized out. // Just log for now. if (::ChainActive()[pindex->nHeight] != pindex) { LogPrint(BCLog::NET, "Announcing block %s not on main chain (tip=%s)\n", hashToAnnounce.ToString(), ::ChainActive().Tip()->GetBlockHash().ToString()); } // If the peer's chain has this block, don't inv it back. if (!PeerHasHeader(&state, pindex)) { pto->vInventoryBlockToSend.push_back(hashToAnnounce); LogPrint(BCLog::NET, "%s: sending inv peer=%d hash=%s\n", __func__, pto->GetId(), hashToAnnounce.ToString()); } } } pto->vBlockHashesToAnnounce.clear(); } // // Message: inventory // std::vector vInv; { LOCK(pto->cs_inventory); vInv.reserve(std::max(pto->vInventoryBlockToSend.size(), INVENTORY_BROADCAST_MAX)); // Add blocks for (const uint256& hash : pto->vInventoryBlockToSend) { vInv.push_back(CInv(MSG_BLOCK, hash)); if (vInv.size() == MAX_INV_SZ) { m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); vInv.clear(); } } pto->vInventoryBlockToSend.clear(); if (pto->m_tx_relay != nullptr) { LOCK(pto->m_tx_relay->cs_tx_inventory); // Check whether periodic sends should happen bool fSendTrickle = pto->HasPermission(PF_NOBAN); if (pto->m_tx_relay->nNextInvSend < current_time) { fSendTrickle = true; if (pto->IsInboundConn()) { pto->m_tx_relay->nNextInvSend = std::chrono::microseconds{m_connman.PoissonNextSendInbound(count_microseconds(current_time), INVENTORY_BROADCAST_INTERVAL)}; } else { // Use half the delay for outbound peers, as there is less privacy concern for them. pto->m_tx_relay->nNextInvSend = PoissonNextSend(current_time, std::chrono::seconds{INVENTORY_BROADCAST_INTERVAL >> 1}); } } // Time to send but the peer has requested we not relay transactions. if (fSendTrickle) { LOCK(pto->m_tx_relay->cs_filter); if (!pto->m_tx_relay->fRelayTxes) pto->m_tx_relay->setInventoryTxToSend.clear(); } // Respond to BIP35 mempool requests if (fSendTrickle && pto->m_tx_relay->fSendMempool) { auto vtxinfo = m_mempool.infoAll(); pto->m_tx_relay->fSendMempool = false; CFeeRate filterrate; { LOCK(pto->m_tx_relay->cs_feeFilter); filterrate = CFeeRate(pto->m_tx_relay->minFeeFilter); } LOCK(pto->m_tx_relay->cs_filter); for (const auto& txinfo : vtxinfo) { 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)) { continue; } if (pto->m_tx_relay->pfilter) { if (!pto->m_tx_relay->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue; } pto->m_tx_relay->filterInventoryKnown.insert(hash); // Responses to MEMPOOL requests bypass the m_recently_announced_invs filter. vInv.push_back(inv); if (vInv.size() == MAX_INV_SZ) { m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); vInv.clear(); } } pto->m_tx_relay->m_last_mempool_req = GetTime(); } // Determine transactions to relay if (fSendTrickle) { // Produce a vector with all candidates for sending std::vector::iterator> vInvTx; vInvTx.reserve(pto->m_tx_relay->setInventoryTxToSend.size()); for (std::set::iterator it = pto->m_tx_relay->setInventoryTxToSend.begin(); it != pto->m_tx_relay->setInventoryTxToSend.end(); it++) { vInvTx.push_back(it); } CFeeRate filterrate; { LOCK(pto->m_tx_relay->cs_feeFilter); filterrate = CFeeRate(pto->m_tx_relay->minFeeFilter); } // 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, 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. unsigned int nRelayedTransactions = 0; LOCK(pto->m_tx_relay->cs_filter); while (!vInvTx.empty() && nRelayedTransactions < INVENTORY_BROADCAST_MAX) { // Fetch the top element from the heap std::pop_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder); std::set::iterator it = vInvTx.back(); vInvTx.pop_back(); uint256 hash = *it; CInv inv(state.m_wtxid_relay ? MSG_WTX : MSG_TX, hash); // Remove it from the to-be-sent set pto->m_tx_relay->setInventoryTxToSend.erase(it); // Check if not in the filter already if (pto->m_tx_relay->filterInventoryKnown.contains(hash)) { continue; } // Not in the mempool anymore? don't bother sending it. auto txinfo = m_mempool.info(ToGenTxid(inv)); 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; } 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(inv); nRelayedTransactions++; { // Expire old relay messages while (!vRelayExpiration.empty() && vRelayExpiration.front().first < count_microseconds(current_time)) { mapRelay.erase(vRelayExpiration.front().second); vRelayExpiration.pop_front(); } auto ret = mapRelay.emplace(txid, std::move(txinfo.tx)); if (ret.second) { vRelayExpiration.emplace_back(count_microseconds(current_time + std::chrono::microseconds{RELAY_TX_CACHE_TIME}), 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(count_microseconds(current_time + std::chrono::microseconds{RELAY_TX_CACHE_TIME}), ret2.first); } } if (vInv.size() == MAX_INV_SZ) { m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); 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); } } } } } if (!vInv.empty()) m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); // Detect whether we're stalling current_time = GetTime(); if (state.nStallingSince && state.nStallingSince < count_microseconds(current_time) - 1000000 * BLOCK_STALLING_TIMEOUT) { // Stalling only triggers when the block download window cannot move. During normal steady state, // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection // should only happen during initial block download. LogPrintf("Peer=%d is stalling block download, disconnecting\n", pto->GetId()); pto->fDisconnect = true; return true; } // In case there is a block that has been in flight from this peer for 2 + 0.5 * N times the block interval // (with N the number of peers from which we're downloading validated blocks), disconnect due to timeout. // We compensate for other peers to prevent killing off peers due to our own downstream link // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes // to unreasonably increase our timeout. if (state.vBlocksInFlight.size() > 0) { QueuedBlock &queuedBlock = state.vBlocksInFlight.front(); int nOtherPeersWithValidatedDownloads = nPeersWithValidatedDownloads - (state.nBlocksInFlightValidHeaders > 0); if (count_microseconds(current_time) > state.nDownloadingSince + consensusParams.nPowTargetSpacing * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) { LogPrintf("Timeout downloading block %s from peer=%d, disconnecting\n", queuedBlock.hash.ToString(), pto->GetId()); pto->fDisconnect = true; return true; } } // Check for headers sync timeouts if (state.fSyncStarted && state.nHeadersSyncTimeout < std::numeric_limits::max()) { // Detect whether this is a stalling initial-headers-sync peer if (pindexBestHeader->GetBlockTime() <= GetAdjustedTime() - 24 * 60 * 60) { if (count_microseconds(current_time) > state.nHeadersSyncTimeout && nSyncStarted == 1 && (nPreferredDownload - state.fPreferredDownload >= 1)) { // Disconnect a peer (without the noban permission) if it is our only sync peer, // and we have others we could be using instead. // Note: If all our peers are inbound, then we won't // disconnect our sync peer for stalling; we have bigger // problems if we can't get any outbound peers. if (!pto->HasPermission(PF_NOBAN)) { LogPrintf("Timeout downloading headers from peer=%d, disconnecting\n", pto->GetId()); pto->fDisconnect = true; return true; } else { LogPrintf("Timeout downloading headers from noban peer=%d, not disconnecting\n", pto->GetId()); // Reset the headers sync state so that we have a // chance to try downloading from a different peer. // Note: this will also result in at least one more // getheaders message to be sent to // this peer (eventually). state.fSyncStarted = false; nSyncStarted--; state.nHeadersSyncTimeout = 0; } } } else { // After we've caught up once, reset the timeout so we can't trigger // disconnect later. state.nHeadersSyncTimeout = std::numeric_limits::max(); } } // Check that outbound peers have reasonable chains // GetTime() is used by this anti-DoS logic so we can test this using mocktime ConsiderEviction(*pto, GetTime()); // // Message: getdata (blocks) // std::vector vGetData; if (!pto->fClient && ((fFetch && !pto->m_limited_node) || !::ChainstateActive().IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) { std::vector vToDownload; NodeId staller = -1; FindNextBlocksToDownload(pto->GetId(), MAX_BLOCKS_IN_TRANSIT_PER_PEER - state.nBlocksInFlight, vToDownload, staller, consensusParams); for (const CBlockIndex *pindex : vToDownload) { uint32_t nFetchFlags = GetFetchFlags(*pto); vGetData.push_back(CInv(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash())); MarkBlockAsInFlight(m_mempool, pto->GetId(), pindex->GetBlockHash(), pindex); LogPrint(BCLog::NET, "Requesting block %s (%d) peer=%d\n", pindex->GetBlockHash().ToString(), pindex->nHeight, pto->GetId()); } if (state.nBlocksInFlight == 0 && staller != -1) { if (State(staller)->nStallingSince == 0) { State(staller)->nStallingSince = count_microseconds(current_time); LogPrint(BCLog::NET, "Stall started peer=%d\n", staller); } } } // // Message: getdata (non-blocks) // std::vector> expired; auto requestable = m_txrequest.GetRequestable(pto->GetId(), current_time, &expired); for (const auto& entry : expired) { LogPrint(BCLog::NET, "timeout of inflight %s %s from peer=%d\n", entry.second.IsWtxid() ? "wtx" : "tx", entry.second.GetHash().ToString(), entry.first); } for (const GenTxid& gtxid : requestable) { if (!AlreadyHaveTx(gtxid, m_mempool)) { LogPrint(BCLog::NET, "Requesting %s %s peer=%d\n", gtxid.IsWtxid() ? "wtx" : "tx", gtxid.GetHash().ToString(), pto->GetId()); vGetData.emplace_back(gtxid.IsWtxid() ? MSG_WTX : (MSG_TX | GetFetchFlags(*pto)), gtxid.GetHash()); if (vGetData.size() >= MAX_GETDATA_SZ) { m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData)); vGetData.clear(); } m_txrequest.RequestedTx(pto->GetId(), gtxid.GetHash(), current_time + GETDATA_TX_INTERVAL); } else { // We have already seen this transaction, no need to download. This is just a belt-and-suspenders, as // this should already be called whenever a transaction becomes AlreadyHaveTx(). m_txrequest.ForgetTxHash(gtxid.GetHash()); } } if (!vGetData.empty()) m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData)); // // Message: feefilter // if (pto->m_tx_relay != nullptr && pto->GetCommonVersion() >= FEEFILTER_VERSION && gArgs.GetBoolArg("-feefilter", DEFAULT_FEEFILTER) && !pto->HasPermission(PF_FORCERELAY) // peers with the forcerelay permission should not filter txs to us ) { CAmount currentFilter = m_mempool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK(); static FeeFilterRounder g_filter_rounder{CFeeRate{DEFAULT_MIN_RELAY_TX_FEE}}; if (m_chainman.ActiveChainstate().IsInitialBlockDownload()) { // Received tx-inv messages are discarded when the active // chainstate is in IBD, so tell the peer to not send them. currentFilter = MAX_MONEY; } else { static const CAmount MAX_FILTER{g_filter_rounder.round(MAX_MONEY)}; if (pto->m_tx_relay->lastSentFeeFilter == MAX_FILTER) { // Send the current filter if we sent MAX_FILTER previously // and made it out of IBD. pto->m_tx_relay->nextSendTimeFeeFilter = count_microseconds(current_time) - 1; } } if (count_microseconds(current_time) > pto->m_tx_relay->nextSendTimeFeeFilter) { CAmount filterToSend = g_filter_rounder.round(currentFilter); // We always have a fee filter of at least minRelayTxFee filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK()); if (filterToSend != pto->m_tx_relay->lastSentFeeFilter) { m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend)); pto->m_tx_relay->lastSentFeeFilter = filterToSend; } pto->m_tx_relay->nextSendTimeFeeFilter = PoissonNextSend(count_microseconds(current_time), AVG_FEEFILTER_BROADCAST_INTERVAL); } // If the fee filter has changed substantially and it's still more than MAX_FEEFILTER_CHANGE_DELAY // until scheduled broadcast, then move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY. else if (count_microseconds(current_time) + MAX_FEEFILTER_CHANGE_DELAY * 1000000 < pto->m_tx_relay->nextSendTimeFeeFilter && (currentFilter < 3 * pto->m_tx_relay->lastSentFeeFilter / 4 || currentFilter > 4 * pto->m_tx_relay->lastSentFeeFilter / 3)) { pto->m_tx_relay->nextSendTimeFeeFilter = count_microseconds(current_time) + GetRandInt(MAX_FEEFILTER_CHANGE_DELAY) * 1000000; } } } // release cs_main return true; } class CNetProcessingCleanup { public: CNetProcessingCleanup() {} ~CNetProcessingCleanup() { // orphan transactions mapOrphanTransactions.clear(); mapOrphanTransactionsByPrev.clear(); g_orphans_by_wtxid.clear(); } }; static CNetProcessingCleanup instance_of_cnetprocessingcleanup;