// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2018 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 #include #include #if defined(NDEBUG) # error "Bitcoin cannot be compiled without assertions." #endif /** 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; /** 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; /** Maximum number of in-flight transactions from a peer */ static constexpr int32_t MAX_PEER_TX_IN_FLIGHT = 100; /** Maximum number of announced transactions from a peer */ static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 2 * MAX_INV_SZ; /** How many microseconds to delay requesting transactions from inbound peers */ static constexpr std::chrono::microseconds INBOUND_PEER_TX_DELAY{std::chrono::seconds{2}}; /** How long to wait (in microseconds) before downloading a transaction from an additional peer */ static constexpr std::chrono::microseconds GETDATA_TX_INTERVAL{std::chrono::seconds{60}}; /** Maximum delay (in microseconds) for transaction requests to avoid biasing some peers over others. */ static constexpr std::chrono::microseconds MAX_GETDATA_RANDOM_DELAY{std::chrono::seconds{2}}; /** How long to wait (in microseconds) before expiring an in-flight getdata request to a peer */ static constexpr std::chrono::microseconds TX_EXPIRY_INTERVAL{GETDATA_TX_INTERVAL * 10}; static_assert(INBOUND_PEER_TX_DELAY >= MAX_GETDATA_RANDOM_DELAY, "To preserve security, MAX_GETDATA_RANDOM_DELAY should not exceed INBOUND_PEER_DELAY"); /** Limit to avoid sending big packets. Not used in processing incoming GETDATA for compatibility */ static const unsigned int MAX_GETDATA_SZ = 1000; 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; }; CCriticalSection g_cs_orphans; std::map mapOrphanTransactions GUARDED_BY(g_cs_orphans); void EraseOrphansFor(NodeId peer); /** Increase a node's misbehavior score. */ void Misbehaving(NodeId nodeid, int howmuch, const std::string& message="") EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Average delay between local address broadcasts in seconds. */ static constexpr unsigned int AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24 * 60 * 60; /** Average delay between peer address broadcasts in seconds. */ static const unsigned int AVG_ADDRESS_BROADCAST_INTERVAL = 30; /** Average delay between trickled inventory transmissions in seconds. * Blocks and whitelisted receivers bypass this, outbound peers get half this delay. */ static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5; /** Maximum number of inventory items to send per transmission. * Limits the impact of low-fee transaction floods. */ static constexpr unsigned int INVENTORY_BROADCAST_MAX = 7 * INVENTORY_BROADCAST_INTERVAL; /** 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; // Internal stuff namespace { /** Number of nodes with fSyncStarted. */ int nSyncStarted GUARDED_BY(cs_main) = 0; /** * Sources of received blocks, saved to be able to send them reject * messages or ban 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. * * Memory used: 1.3 MB */ std::unique_ptr recentRejects GUARDED_BY(cs_main); uint256 hashRecentRejectsChainTip GUARDED_BY(cs_main); /** 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 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 */ 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); } }; std::map::iterator, IteratorComparator>> mapOrphanTransactionsByPrev GUARDED_BY(g_cs_orphans); std::vector::iterator> g_orphan_list GUARDED_BY(g_cs_orphans); //! For random eviction static size_t vExtraTxnForCompactIt GUARDED_BY(g_cs_orphans) = 0; static std::vector> vExtraTxnForCompact GUARDED_BY(g_cs_orphans); } // namespace namespace { struct CBlockReject { unsigned char chRejectCode; std::string strRejectReason; uint256 hashBlock; }; /** * 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; //! Whether we have a fully established connection. bool fCurrentlyConnected; //! Accumulated misbehaviour score for this peer. int nMisbehavior; //! Whether this peer should be disconnected and banned (unless whitelisted). bool fShouldBan; //! String name of this peer (debugging/logging purposes). const std::string name; //! List of asynchronously-determined block rejections to notify this peer about. std::vector rejects; //! 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 * Only in effect for outbound, non-manual connections, with * m_protect == false * Algorithm: 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. */ 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; /* * State associated with transaction download. * * Tx download algorithm: * * When inv comes in, queue up (process_time, txid) inside the peer's * CNodeState (m_tx_process_time) as long as m_tx_announced for the peer * isn't too big (MAX_PEER_TX_ANNOUNCEMENTS). * * The process_time for a transaction is set to nNow for outbound peers, * nNow + 2 seconds for inbound peers. This is the time at which we'll * consider trying to request the transaction from the peer in * SendMessages(). The delay for inbound peers is to allow outbound peers * a chance to announce before we request from inbound peers, to prevent * an adversary from using inbound connections to blind us to a * transaction (InvBlock). * * When we call SendMessages() for a given peer, * we will loop over the transactions in m_tx_process_time, looking * at the transactions whose process_time <= nNow. We'll request each * such transaction that we don't have already and that hasn't been * requested from another peer recently, up until we hit the * MAX_PEER_TX_IN_FLIGHT limit for the peer. Then we'll update * g_already_asked_for for each requested txid, storing the time of the * GETDATA request. We use g_already_asked_for to coordinate transaction * requests amongst our peers. * * For transactions that we still need but we have already recently * requested from some other peer, we'll reinsert (process_time, txid) * back into the peer's m_tx_process_time at the point in the future at * which the most recent GETDATA request would time out (ie * GETDATA_TX_INTERVAL + the request time stored in g_already_asked_for). * We add an additional delay for inbound peers, again to prefer * attempting download from outbound peers first. * We also add an extra small random delay up to 2 seconds * to avoid biasing some peers over others. (e.g., due to fixed ordering * of peer processing in ThreadMessageHandler). * * When we receive a transaction from a peer, we remove the txid from the * peer's m_tx_in_flight set and from their recently announced set * (m_tx_announced). We also clear g_already_asked_for for that entry, so * that if somehow the transaction is not accepted but also not added to * the reject filter, then we will eventually redownload from other * peers. */ struct TxDownloadState { /* Track when to attempt download of announced transactions (process * time in micros -> txid) */ std::multimap m_tx_process_time; //! Store all the transactions a peer has recently announced std::set m_tx_announced; //! Store transactions which were requested by us, with timestamp std::map m_tx_in_flight; //! Periodically check for stuck getdata requests std::chrono::microseconds m_check_expiry_timer{0}; }; TxDownloadState m_tx_download; //! Whether this peer is an inbound connection bool m_is_inbound; //! Whether this peer is a manual connection bool m_is_manual_connection; CNodeState(CAddress addrIn, std::string addrNameIn, bool is_inbound, bool is_manual) : address(addrIn), name(std::move(addrNameIn)), m_is_inbound(is_inbound), m_is_manual_connection (is_manual) { fCurrentlyConnected = false; nMisbehavior = 0; fShouldBan = false; 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; } }; // Keeps track of the time (in microseconds) when transactions were requested last time limitedmap g_already_asked_for GUARDED_BY(cs_main)(MAX_INV_SZ); /** 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(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->fInbound || node->fWhitelisted) && !node->fOneShot && !node->fClient; nPreferredDownload += state->fPreferredDownload; } static void PushNodeVersion(CNode *pnode, CConnman* connman, int64_t nTime) { 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 : CAddress(CService(), addr.nServices)); CAddress addrMe = CAddress(CService(), nLocalNodeServices); connman->PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::VERSION, PROTOCOL_VERSION, (uint64_t)nLocalNodeServices, nTime, addrYou, addrMe, nonce, strSubVersion, nNodeStartingHeight, ::g_relay_txes)); 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); } } // 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, GetTimeMicros()); } 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(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 = GetTimeMicros(); } 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){ 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){ AssertLockHeld(cs_main); connman->PushMessage(pnodeStop, CNetMsgMaker(pnodeStop->GetSendVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/false, nCMPCTBLOCKVersion)); return true; }); lNodesAnnouncingHeaderAndIDs.pop_front(); } connman->PushMessage(pfrom, CNetMsgMaker(pfrom->GetSendVersion()).Make(NetMsgType::SENDCMPCT, /*fAnnounceUsingCMPCTBLOCK=*/true, nCMPCTBLOCKVersion)); 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; } } } } void EraseTxRequest(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { g_already_asked_for.erase(txid); } std::chrono::microseconds GetTxRequestTime(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { auto it = g_already_asked_for.find(txid); if (it != g_already_asked_for.end()) { return it->second; } return {}; } void UpdateTxRequestTime(const uint256& txid, std::chrono::microseconds request_time) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { auto it = g_already_asked_for.find(txid); if (it == g_already_asked_for.end()) { g_already_asked_for.insert(std::make_pair(txid, request_time)); } else { g_already_asked_for.update(it, request_time); } } std::chrono::microseconds CalculateTxGetDataTime(const uint256& txid, std::chrono::microseconds current_time, bool use_inbound_delay) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { std::chrono::microseconds process_time; const auto last_request_time = GetTxRequestTime(txid); // First time requesting this tx if (last_request_time.count() == 0) { process_time = current_time; } else { // Randomize the delay to avoid biasing some peers over others (such as due to // fixed ordering of peer processing in ThreadMessageHandler) process_time = last_request_time + GETDATA_TX_INTERVAL + GetRandMicros(MAX_GETDATA_RANDOM_DELAY); } // We delay processing announcements from inbound peers if (use_inbound_delay) process_time += INBOUND_PEER_TX_DELAY; return process_time; } void RequestTx(CNodeState* state, const uint256& txid, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { CNodeState::TxDownloadState& peer_download_state = state->m_tx_download; if (peer_download_state.m_tx_announced.size() >= MAX_PEER_TX_ANNOUNCEMENTS || peer_download_state.m_tx_process_time.size() >= MAX_PEER_TX_ANNOUNCEMENTS || peer_download_state.m_tx_announced.count(txid)) { // Too many queued announcements from this peer, or we already have // this announcement return; } peer_download_state.m_tx_announced.insert(txid); // Calculate the time to try requesting this transaction. Use // fPreferredDownload as a proxy for outbound peers. const auto process_time = CalculateTxGetDataTime(txid, current_time, !state->fPreferredDownload); peer_download_state.m_tx_process_time.emplace(process_time, txid); } } // namespace // 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; } // Returns true for outbound peers, excluding manual connections, feelers, and // one-shots static bool IsOutboundDisconnectionCandidate(const CNode *node) { return !(node->fInbound || node->m_manual_connection || node->fFeeler || node->fOneShot); } void PeerLogicValidation::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, std::move(addrName), pnode->fInbound, pnode->m_manual_connection)); } if(!pnode->fInbound) PushNodeVersion(pnode, connman, GetTime()); } void PeerLogicValidation::FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTime) { fUpdateConnectionTime = false; LOCK(cs_main); CNodeState *state = State(nodeid); assert(state != nullptr); if (state->fSyncStarted) nSyncStarted--; if (state->nMisbehavior == 0 && state->fCurrentlyConnected) { fUpdateConnectionTime = true; } for (const QueuedBlock& entry : state->vBlocksInFlight) { mapBlocksInFlight.erase(entry.hash); } EraseOrphansFor(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); 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); } LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid); } bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) { LOCK(cs_main); CNodeState *state = State(nodeid); if (state == nullptr) return false; stats.nMisbehavior = state->nMisbehavior; 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); } 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); 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(); 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; } /** * Mark a misbehaving peer to be banned depending upon the value of `-banscore`. */ void Misbehaving(NodeId pnode, int howmuch, const std::string& message) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { if (howmuch == 0) return; CNodeState *state = State(pnode); if (state == nullptr) return; state->nMisbehavior += howmuch; int banscore = gArgs.GetArg("-banscore", DEFAULT_BANSCORE_THRESHOLD); std::string message_prefixed = message.empty() ? "" : (": " + message); if (state->nMisbehavior >= banscore && state->nMisbehavior - howmuch < banscore) { LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d) BAN THRESHOLD EXCEEDED%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); state->fShouldBan = true; } else LogPrint(BCLog::NET, "%s: %s peer=%d (%d -> %d)%s\n", __func__, state->name, pnode, state->nMisbehavior-howmuch, state->nMisbehavior, message_prefixed); } /** * Returns true if the given validation state result may result in a peer * banning/disconnecting us. We use this to determine which unaccepted * transactions from a whitelisted peer that we can safely relay. */ static bool TxRelayMayResultInDisconnect(const CValidationState& state) { assert(IsTransactionReason(state.GetReason())); return state.GetReason() == ValidationInvalidReason::CONSENSUS; } /** * Potentially ban a node based on the contents of a CValidationState object * * @param[in] via_compact_block: this bool is passed in because net_processing should * punish peers differently depending on whether the data was provided in a compact * block message or not. If the compact block had a valid header, but contained invalid * txs, the peer should not be punished. See BIP 152. * * @return Returns true if the peer was punished (probably disconnected) * * Changes here may need to be reflected in TxRelayMayResultInDisconnect(). */ static bool MaybePunishNode(NodeId nodeid, const CValidationState& state, bool via_compact_block, const std::string& message = "") { switch (state.GetReason()) { case ValidationInvalidReason::NONE: break; // The node is providing invalid data: case ValidationInvalidReason::CONSENSUS: case ValidationInvalidReason::BLOCK_MUTATED: if (!via_compact_block) { LOCK(cs_main); Misbehaving(nodeid, 100, message); return true; } break; case ValidationInvalidReason::CACHED_INVALID: { LOCK(cs_main); CNodeState *node_state = State(nodeid); if (node_state == nullptr) { break; } // Ban outbound (but not inbound) peers if on an invalid chain. // Exempt HB compact block peers and manual connections. if (!via_compact_block && !node_state->m_is_inbound && !node_state->m_is_manual_connection) { Misbehaving(nodeid, 100, message); return true; } break; } case ValidationInvalidReason::BLOCK_INVALID_HEADER: case ValidationInvalidReason::BLOCK_CHECKPOINT: case ValidationInvalidReason::BLOCK_INVALID_PREV: { LOCK(cs_main); Misbehaving(nodeid, 100, message); } return true; // Conflicting (but not necessarily invalid) data or different policy: case ValidationInvalidReason::BLOCK_MISSING_PREV: { // TODO: Handle this much more gracefully (10 DoS points is super arbitrary) LOCK(cs_main); Misbehaving(nodeid, 10, message); } return true; case ValidationInvalidReason::RECENT_CONSENSUS_CHANGE: case ValidationInvalidReason::BLOCK_TIME_FUTURE: case ValidationInvalidReason::TX_NOT_STANDARD: case ValidationInvalidReason::TX_MISSING_INPUTS: case ValidationInvalidReason::TX_PREMATURE_SPEND: case ValidationInvalidReason::TX_WITNESS_MUTATED: case ValidationInvalidReason::TX_CONFLICT: case ValidationInvalidReason::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); } PeerLogicValidation::PeerLogicValidation(CConnman* connmanIn, BanMan* banman, CScheduler &scheduler, bool enable_bip61) : connman(connmanIn), m_banman(banman), m_stale_tip_check_time(0), m_enable_bip61(enable_bip61) { // Initialize global variables that cannot be constructed at startup. recentRejects.reset(new CRollingBloomFilter(120000, 0.000001)); const Consensus::Params& consensusParams = Params().GetConsensus(); // 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(std::bind(&PeerLogicValidation::CheckForStaleTipAndEvictPeers, this, consensusParams), EXTRA_PEER_CHECK_INTERVAL * 1000); } /** * Evict orphan txn pool entries (EraseOrphanTx) based on a newly connected * block. Also save the time of the last tip update. */ void PeerLogicValidation::BlockConnected(const std::shared_ptr& pblock, const CBlockIndex* pindex, const std::vector& vtxConflicted) { 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(); } // All of the following cache a recent block, and are protected by cs_most_recent_block static CCriticalSection 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 PeerLogicValidation::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, Params().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; } connman->ForEachNode([this, &pcmpctblock, pindex, &msgMaker, fWitnessEnabled, &hashBlock](CNode* pnode) { AssertLockHeld(cs_main); // TODO: Avoid the repeated-serialization here if (pnode->nVersion < 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", "PeerLogicValidation::NewPoWValidBlock", hashBlock.ToString(), pnode->GetId()); 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 PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) { const int nNewHeight = pindexNew->nHeight; connman->SetBestHeight(nNewHeight); SetServiceFlagsIBDCache(!fInitialDownload); if (!fInitialDownload) { // 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 inventory, but don't relay old inventory during initial block download. connman->ForEachNode([nNewHeight, &vHashes](CNode* pnode) { if (nNewHeight > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : 0)) { for (const uint256& hash : reverse_iterate(vHashes)) { pnode->PushBlockHash(hash); } } }); connman->WakeMessageHandler(); } } /** * Handle invalid block rejection and consequent peer banning, maintain which * peers announce compact blocks. */ void PeerLogicValidation::BlockChecked(const CBlock& block, const CValidationState& state) { LOCK(cs_main); const uint256 hash(block.GetHash()); std::map>::iterator it = mapBlockSource.find(hash); if (state.IsInvalid()) { // Don't send reject message with code 0 or an internal reject code. if (it != mapBlockSource.end() && State(it->second.first) && state.GetRejectCode() > 0 && state.GetRejectCode() < REJECT_INTERNAL) { CBlockReject reject = {(unsigned char)state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), hash}; State(it->second.first)->rejects.push_back(reject); MaybePunishNode(/*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, connman); } } if (it != mapBlockSource.end()) mapBlockSource.erase(it); } ////////////////////////////////////////////////////////////////////////////// // // Messages // bool static AlreadyHave(const CInv& inv) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { switch (inv.type) { case MSG_TX: case MSG_WITNESS_TX: { 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(); } { LOCK(g_cs_orphans); if (mapOrphanTransactions.count(inv.hash)) return true; } return recentRejects->contains(inv.hash) || mempool.exists(inv.hash) || pcoinsTip->HaveCoinInCache(COutPoint(inv.hash, 0)) || // Best effort: only try output 0 and 1 pcoinsTip->HaveCoinInCache(COutPoint(inv.hash, 1)); } case MSG_BLOCK: case MSG_WITNESS_BLOCK: return LookupBlockIndex(inv.hash) != nullptr; } // Don't know what it is, just say we already got one return true; } void RelayTransaction(const uint256& txid, const CConnman& connman) { CInv inv(MSG_TX, txid); connman.ForEachNode([&inv](CNode* pnode) { pnode->PushInventory(inv); }); } static void RelayAddress(const CAddress& addr, bool fReachable, CConnman* connman) { unsigned int nRelayNodes = fReachable ? 2 : 1; // limited relaying of addresses outside our network(s) // 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 addrKnowns 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; std::array,2> best{{{0, nullptr}, {0, nullptr}}}; assert(nRelayNodes <= best.size()); auto sortfunc = [&best, &hasher, nRelayNodes](CNode* pnode) { if (pnode->nVersion >= CADDR_TIME_VERSION) { 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) { CValidationState state; if (!ActivateBestChain(state, Params(), a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", FormatStateMessage(state)); } } 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->GetSendVersion()); // disconnect node in case we have reached the outbound limit for serving historical blocks // never disconnect whitelisted nodes if (send && connman->OutboundTargetReached(true) && ( ((pindexBestHeader != nullptr) && (pindexBestHeader->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.type == MSG_FILTERED_BLOCK) && !pfrom->fWhitelisted) { 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->fWhitelisted && ( (((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.type == MSG_WITNESS_BLOCK) { // 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.type == MSG_BLOCK) connman->PushMessage(pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, *pblock)); else if (inv.type == MSG_WITNESS_BLOCK) connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::BLOCK, *pblock)); else if (inv.type == MSG_FILTERED_BLOCK) { bool sendMerkleBlock = false; CMerkleBlock merkleBlock; { LOCK(pfrom->cs_filter); if (pfrom->pfilter) { sendMerkleBlock = true; merkleBlock = CMerkleBlock(*pblock, *pfrom->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.type == MSG_CMPCT_BLOCK) { // 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) { // Bypass PushInventory, 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(); } } } void static ProcessGetData(CNode* pfrom, const CChainParams& chainparams, CConnman* connman, const std::atomic& interruptMsgProc) LOCKS_EXCLUDED(cs_main) { AssertLockNotHeld(cs_main); std::deque::iterator it = pfrom->vRecvGetData.begin(); std::vector vNotFound; const CNetMsgMaker msgMaker(pfrom->GetSendVersion()); { LOCK(cs_main); while (it != pfrom->vRecvGetData.end() && (it->type == MSG_TX || it->type == MSG_WITNESS_TX)) { if (interruptMsgProc) return; // Don't bother if send buffer is too full to respond anyway if (pfrom->fPauseSend) break; const CInv &inv = *it; it++; // Send stream from relay memory bool push = false; auto mi = mapRelay.find(inv.hash); int nSendFlags = (inv.type == MSG_TX ? SERIALIZE_TRANSACTION_NO_WITNESS : 0); if (mi != mapRelay.end()) { connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second)); push = true; } else if (pfrom->timeLastMempoolReq) { auto txinfo = mempool.info(inv.hash); // To protect privacy, do not answer getdata using the mempool when // that TX couldn't have been INVed in reply to a MEMPOOL request. if (txinfo.tx && txinfo.nTime <= pfrom->timeLastMempoolReq) { connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::TX, *txinfo.tx)); push = true; } } if (!push) { vNotFound.push_back(inv); } } } // release cs_main if (it != pfrom->vRecvGetData.end() && !pfrom->fPauseSend) { const CInv &inv = *it; if (inv.type == MSG_BLOCK || inv.type == MSG_FILTERED_BLOCK || inv.type == MSG_CMPCT_BLOCK || inv.type == MSG_WITNESS_BLOCK) { it++; ProcessGetBlockData(pfrom, chainparams, inv, connman); } } // Unknown types in the GetData stay in vRecvGetData and block any future // message from this peer, see vRecvGetData check in ProcessMessages(). // Depending on future p2p changes, we might either drop unknown getdata on // the floor or disconnect the peer. pfrom->vRecvGetData.erase(pfrom->vRecvGetData.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(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; } inline void static SendBlockTransactions(const CBlock& block, const BlockTransactionsRequest& req, CNode* pfrom, CConnman* connman) { BlockTransactions resp(req); for (size_t i = 0; i < req.indexes.size(); i++) { if (req.indexes[i] >= block.vtx.size()) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 100, strprintf("Peer %d sent us a getblocktxn with out-of-bounds tx indices", pfrom->GetId())); return; } resp.txn[i] = block.vtx[req.indexes[i]]; } LOCK(cs_main); const CNetMsgMaker msgMaker(pfrom->GetSendVersion()); int nSendFlags = State(pfrom->GetId())->fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS; connman->PushMessage(pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp)); } bool static ProcessHeadersMessage(CNode *pfrom, CConnman *connman, const std::vector& headers, const CChainParams& chainparams, bool via_compact_block) { const CNetMsgMaker msgMaker(pfrom->GetSendVersion()); size_t nCount = headers.size(); if (nCount == 0) { // Nothing interesting. Stop asking this peers for more headers. return true; } 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++; 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); } return true; } uint256 hashLastBlock; for (const CBlockHeader& header : headers) { if (!hashLastBlock.IsNull() && header.hashPrevBlock != hashLastBlock) { Misbehaving(pfrom->GetId(), 20, "non-continuous headers sequence"); return false; } 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; } } CValidationState state; CBlockHeader first_invalid_header; if (!ProcessNewBlockHeaders(headers, state, chainparams, &pindexLast, &first_invalid_header)) { if (state.IsInvalid()) { MaybePunishNode(pfrom->GetId(), state, via_compact_block, "invalid header received"); return false; } } { 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); connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexLast), uint256())); } bool fCanDirectFetch = CanDirectFetch(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, 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(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); } 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 using an outbound slot (unless // whitelisted or addnode). // 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 (IsOutboundDisconnectionCandidate(pfrom)) { LogPrintf("Disconnecting outbound peer %d -- headers chain has insufficient work\n", pfrom->GetId()); pfrom->fDisconnect = true; } } } if (!pfrom->fDisconnect && IsOutboundDisconnectionCandidate(pfrom) && nodestate->pindexBestKnownBlock != nullptr) { // If this is an outbound peer, check to see if we should protect // it from the bad/lagging chain logic. 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 true; } void static ProcessOrphanTx(CConnman* connman, std::set& orphan_work_set, std::list& removed_txn) EXCLUSIVE_LOCKS_REQUIRED(cs_main, g_cs_orphans) { AssertLockHeld(cs_main); AssertLockHeld(g_cs_orphans); std::set setMisbehaving; bool done = false; while (!done && !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; const CTransaction& orphanTx = *porphanTx; NodeId fromPeer = orphan_it->second.fromPeer; bool fMissingInputs2 = false; // Use a new CValidationState because orphans come from different peers (and we call // MaybePunishNode based on the source peer from the orphan map, not based on the peer // that relayed the previous transaction). CValidationState orphan_state; if (setMisbehaving.count(fromPeer)) continue; if (AcceptToMemoryPool(mempool, orphan_state, porphanTx, &fMissingInputs2, &removed_txn, false /* bypass_limits */, 0 /* nAbsurdFee */)) { LogPrint(BCLog::MEMPOOL, " accepted orphan tx %s\n", orphanHash.ToString()); RelayTransaction(orphanHash, *connman); for (unsigned int i = 0; i < orphanTx.vout.size(); i++) { auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(orphanHash, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { for (const auto& elem : it_by_prev->second) { orphan_work_set.insert(elem->first); } } } EraseOrphanTx(orphanHash); done = true; } else if (!fMissingInputs2) { if (orphan_state.IsInvalid()) { // Punish peer that gave us an invalid orphan tx if (MaybePunishNode(fromPeer, orphan_state, /*via_compact_block*/ false)) { setMisbehaving.insert(fromPeer); } LogPrint(BCLog::MEMPOOL, " invalid orphan tx %s\n", orphanHash.ToString()); } // Has inputs but not accepted to mempool // Probably non-standard or insufficient fee LogPrint(BCLog::MEMPOOL, " removed orphan tx %s\n", orphanHash.ToString()); assert(IsTransactionReason(orphan_state.GetReason())); if (!orphanTx.HasWitness() && orphan_state.GetReason() != ValidationInvalidReason::TX_WITNESS_MUTATED) { // Do not use rejection cache for witness transactions or // witness-stripped transactions, as they can have been malleated. // See https://github.com/bitcoin/bitcoin/issues/8279 for details. assert(recentRejects); recentRejects->insert(orphanHash); } EraseOrphanTx(orphanHash); done = true; } mempool.check(pcoinsTip.get()); } } bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStream& vRecv, int64_t nTimeReceived, const CChainParams& chainparams, CConnman* connman, const std::atomic& interruptMsgProc, bool enable_bip61) { LogPrint(BCLog::NET, "received: %s (%u bytes) peer=%d\n", SanitizeString(strCommand), vRecv.size(), pfrom->GetId()); if (gArgs.IsArgSet("-dropmessagestest") && GetRand(gArgs.GetArg("-dropmessagestest", 0)) == 0) { LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n"); return true; } if (!(pfrom->GetLocalServices() & NODE_BLOOM) && (strCommand == NetMsgType::FILTERLOAD || strCommand == NetMsgType::FILTERADD)) { if (pfrom->nVersion >= NO_BLOOM_VERSION) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 100); return false; } else { pfrom->fDisconnect = true; return false; } } if (strCommand == NetMsgType::REJECT) { if (LogAcceptCategory(BCLog::NET)) { try { std::string strMsg; unsigned char ccode; std::string strReason; vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH); std::ostringstream ss; ss << strMsg << " code " << itostr(ccode) << ": " << strReason; if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX) { uint256 hash; vRecv >> hash; ss << ": hash " << hash.ToString(); } LogPrint(BCLog::NET, "Reject %s\n", SanitizeString(ss.str())); } catch (const std::ios_base::failure&) { // Avoid feedback loops by preventing reject messages from triggering a new reject message. LogPrint(BCLog::NET, "Unparseable reject message received\n"); } } return true; } if (strCommand == NetMsgType::VERSION) { // Each connection can only send one version message if (pfrom->nVersion != 0) { if (enable_bip61) { connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_DUPLICATE, std::string("Duplicate version message"))); } LOCK(cs_main); Misbehaving(pfrom->GetId(), 1); return false; } int64_t nTime; CAddress addrMe; CAddress addrFrom; uint64_t nNonce = 1; uint64_t nServiceInt; ServiceFlags nServices; int nVersion; int nSendVersion; std::string cleanSubVer; int nStartingHeight = -1; bool fRelay = true; vRecv >> nVersion >> nServiceInt >> nTime >> addrMe; nSendVersion = std::min(nVersion, PROTOCOL_VERSION); nServices = ServiceFlags(nServiceInt); if (!pfrom->fInbound) { connman->SetServices(pfrom->addr, nServices); } if (!pfrom->fInbound && !pfrom->fFeeler && !pfrom->m_manual_connection && !HasAllDesirableServiceFlags(nServices)) { LogPrint(BCLog::NET, "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom->GetId(), nServices, GetDesirableServiceFlags(nServices)); if (enable_bip61) { connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_NONSTANDARD, strprintf("Expected to offer services %08x", GetDesirableServiceFlags(nServices)))); } pfrom->fDisconnect = true; return false; } 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); if (enable_bip61) { connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_OBSOLETE, strprintf("Version must be %d or greater", MIN_PEER_PROTO_VERSION))); } pfrom->fDisconnect = true; return false; } 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->fInbound && !connman->CheckIncomingNonce(nNonce)) { LogPrintf("connected to self at %s, disconnecting\n", pfrom->addr.ToString()); pfrom->fDisconnect = true; return true; } if (pfrom->fInbound && addrMe.IsRoutable()) { SeenLocal(addrMe); } // Be shy and don't send version until we hear if (pfrom->fInbound) PushNodeVersion(pfrom, connman, GetAdjustedTime()); connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).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)); { LOCK(pfrom->cs_filter); pfrom->fRelayTxes = fRelay; // set to true after we get the first filter* message } // Change version pfrom->SetSendVersion(nSendVersion); pfrom->nVersion = nVersion; 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->fInbound) { // Advertise our address 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 if (pfrom->fOneShot || pfrom->nVersion >= CADDR_TIME_VERSION || connman->GetAddressCount() < 1000) { connman->PushMessage(pfrom, CNetMsgMaker(nSendVersion).Make(NetMsgType::GETADDR)); pfrom->fGetAddr = true; } 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 (pfrom->nVersion <= 70012) { CDataStream finalAlert(ParseHex("60010000000000000000000000ffffff7f00000000ffffff7ffeffff7f01ffffff7f00000000ffffff7f00ffffff7f002f555247454e543a20416c657274206b657920636f6d70726f6d697365642c2075706772616465207265717569726564004630440220653febd6410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3abd5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fecaae66ecf689bf71b50"), SER_NETWORK, PROTOCOL_VERSION); connman->PushMessage(pfrom, CNetMsgMaker(nSendVersion).Make("alert", finalAlert)); } // Feeler connections exist only to verify if address is online. if (pfrom->fFeeler) { assert(pfrom->fInbound == false); pfrom->fDisconnect = true; } return true; } if (pfrom->nVersion == 0) { // Must have a version message before anything else LOCK(cs_main); Misbehaving(pfrom->GetId(), 1); return false; } // At this point, the outgoing message serialization version can't change. const CNetMsgMaker msgMaker(pfrom->GetSendVersion()); if (strCommand == NetMsgType::VERACK) { pfrom->SetRecvVersion(std::min(pfrom->nVersion.load(), PROTOCOL_VERSION)); if (!pfrom->fInbound) { // Mark this node as currently connected, so we update its timestamp later. LOCK(cs_main); State(pfrom->GetId())->fCurrentlyConnected = true; LogPrintf("New outbound peer connected: version: %d, blocks=%d, peer=%d%s\n", pfrom->nVersion.load(), pfrom->nStartingHeight, pfrom->GetId(), (fLogIPs ? strprintf(", peeraddr=%s", pfrom->addr.ToString()) : "")); } if (pfrom->nVersion >= 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) connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDHEADERS)); } if (pfrom->nVersion >= 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) connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion)); nCMPCTBLOCKVersion = 1; connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::SENDCMPCT, fAnnounceUsingCMPCTBLOCK, nCMPCTBLOCKVersion)); } pfrom->fSuccessfullyConnected = true; return true; } if (!pfrom->fSuccessfullyConnected) { // Must have a verack message before anything else LOCK(cs_main); Misbehaving(pfrom->GetId(), 1); return false; } if (strCommand == NetMsgType::ADDR) { std::vector vAddr; vRecv >> vAddr; // Don't want addr from older versions unless seeding if (pfrom->nVersion < CADDR_TIME_VERSION && connman->GetAddressCount() > 1000) return true; if (vAddr.size() > 1000) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 20, strprintf("message addr size() = %u", vAddr.size())); return false; } // Store the new addresses std::vector vAddrOk; int64_t nNow = GetAdjustedTime(); int64_t nSince = nNow - 10 * 60; for (CAddress& addr : vAddr) { if (interruptMsgProc) return true; // 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 (g_banman->IsBanned(addr)) continue; // Do not process banned addresses beyond remembering we received them bool fReachable = IsReachable(addr); if (addr.nTime > nSince && !pfrom->fGetAddr && vAddr.size() <= 10 && addr.IsRoutable()) { // Relay to a limited number of other nodes RelayAddress(addr, fReachable, connman); } // Do not store addresses outside our network if (fReachable) vAddrOk.push_back(addr); } connman->AddNewAddresses(vAddrOk, pfrom->addr, 2 * 60 * 60); if (vAddr.size() < 1000) pfrom->fGetAddr = false; if (pfrom->fOneShot) pfrom->fDisconnect = true; return true; } if (strCommand == NetMsgType::SENDHEADERS) { LOCK(cs_main); State(pfrom->GetId())->fPreferHeaders = true; return true; } if (strCommand == 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; if (!State(pfrom->GetId())->fSupportsDesiredCmpctVersion) { if (pfrom->GetLocalServices() & NODE_WITNESS) State(pfrom->GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 2); else State(pfrom->GetId())->fSupportsDesiredCmpctVersion = (nCMPCTBLOCKVersion == 1); } } return true; } if (strCommand == NetMsgType::INV) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 20, strprintf("message inv size() = %u", vInv.size())); return false; } bool fBlocksOnly = !g_relay_txes; // Allow whitelisted peers to send data other than blocks in blocks only mode if whitelistrelay is true if (pfrom->fWhitelisted && gArgs.GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY)) fBlocksOnly = false; LOCK(cs_main); uint32_t nFetchFlags = GetFetchFlags(pfrom); const auto current_time = GetTime(); for (CInv &inv : vInv) { if (interruptMsgProc) return true; bool fAlreadyHave = AlreadyHave(inv); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom->GetId()); if (inv.type == MSG_TX) { inv.type |= nFetchFlags; } if (inv.type == MSG_BLOCK) { UpdateBlockAvailability(pfrom->GetId(), inv.hash); if (!fAlreadyHave && !fImporting && !fReindex && !mapBlocksInFlight.count(inv.hash)) { // We used to request the full block here, but since headers-announcements are now the // primary method of announcement on the network, and since, in the case that a node // fell back to inv we probably have a reorg which we should get the headers for first, // we now only provide a getheaders response here. When we receive the headers, we will // then ask for the blocks we need. connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), inv.hash)); LogPrint(BCLog::NET, "getheaders (%d) %s to peer=%d\n", pindexBestHeader->nHeight, inv.hash.ToString(), pfrom->GetId()); } } else { pfrom->AddInventoryKnown(inv); if (fBlocksOnly) { LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol peer=%d\n", inv.hash.ToString(), pfrom->GetId()); } else if (!fAlreadyHave && !fImporting && !fReindex && !::ChainstateActive().IsInitialBlockDownload()) { RequestTx(State(pfrom->GetId()), inv.hash, current_time); } } } return true; } if (strCommand == NetMsgType::GETDATA) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 20, strprintf("message getdata size() = %u", vInv.size())); return false; } 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()); } pfrom->vRecvGetData.insert(pfrom->vRecvGetData.end(), vInv.begin(), vInv.end()); ProcessGetData(pfrom, chainparams, connman, interruptMsgProc); return true; } if (strCommand == 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 true; } // 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; } CValidationState state; if (!ActivateBestChain(state, Params(), a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", FormatStateMessage(state)); } } 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 / 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; } pfrom->PushInventory(CInv(MSG_BLOCK, 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 true; } if (strCommand == 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(*recent_block, req, pfrom, connman); return true; } 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 true; } if (pindex->nHeight < ::ChainActive().Height() - MAX_BLOCKTXN_DEPTH) { // 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; inv.type = State(pfrom->GetId())->fWantsCmpctWitness ? MSG_WITNESS_BLOCK : MSG_BLOCK; inv.hash = req.blockhash; pfrom->vRecvGetData.push_back(inv); // The message processing loop will go around again (without pausing) and we'll respond then (without cs_main) return true; } CBlock block; bool ret = ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()); assert(ret); SendBlockTransactions(block, req, pfrom, connman); return true; } if (strCommand == 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 true; } LOCK(cs_main); if (::ChainstateActive().IsInitialBlockDownload() && !pfrom->fWhitelisted) { LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom->GetId()); return true; } 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 true; } if (!BlockRequestAllowed(pindex, 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 true; } } 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(); connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::HEADERS, vHeaders)); return true; } if (strCommand == NetMsgType::TX) { // Stop processing the transaction early if // We are in blocks only mode and peer is either not whitelisted or whitelistrelay is off if (!g_relay_txes && (!pfrom->fWhitelisted || !gArgs.GetBoolArg("-whitelistrelay", DEFAULT_WHITELISTRELAY))) { LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom->GetId()); return true; } CTransactionRef ptx; vRecv >> ptx; const CTransaction& tx = *ptx; CInv inv(MSG_TX, tx.GetHash()); pfrom->AddInventoryKnown(inv); LOCK2(cs_main, g_cs_orphans); bool fMissingInputs = false; CValidationState state; CNodeState* nodestate = State(pfrom->GetId()); nodestate->m_tx_download.m_tx_announced.erase(inv.hash); nodestate->m_tx_download.m_tx_in_flight.erase(inv.hash); EraseTxRequest(inv.hash); std::list lRemovedTxn; if (!AlreadyHave(inv) && AcceptToMemoryPool(mempool, state, ptx, &fMissingInputs, &lRemovedTxn, false /* bypass_limits */, 0 /* nAbsurdFee */)) { mempool.check(pcoinsTip.get()); RelayTransaction(tx.GetHash(), *connman); for (unsigned int i = 0; i < tx.vout.size(); i++) { auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(inv.hash, i)); if (it_by_prev != mapOrphanTransactionsByPrev.end()) { for (const auto& elem : it_by_prev->second) { pfrom->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(), mempool.size(), mempool.DynamicMemoryUsage() / 1000); // Recursively process any orphan transactions that depended on this one ProcessOrphanTx(connman, pfrom->orphan_work_set, lRemovedTxn); } else if (fMissingInputs) { bool fRejectedParents = false; // It may be the case that the orphans parents have all been rejected for (const CTxIn& txin : tx.vin) { if (recentRejects->contains(txin.prevout.hash)) { fRejectedParents = true; break; } } if (!fRejectedParents) { uint32_t nFetchFlags = GetFetchFlags(pfrom); const auto current_time = GetTime(); for (const CTxIn& txin : tx.vin) { CInv _inv(MSG_TX | nFetchFlags, txin.prevout.hash); pfrom->AddInventoryKnown(_inv); if (!AlreadyHave(_inv)) RequestTx(State(pfrom->GetId()), _inv.hash, current_time); } AddOrphanTx(ptx, pfrom->GetId()); // DoS prevention: do not allow mapOrphanTransactions to grow unbounded 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. recentRejects->insert(tx.GetHash()); } } else { assert(IsTransactionReason(state.GetReason())); if (!tx.HasWitness() && state.GetReason() != ValidationInvalidReason::TX_WITNESS_MUTATED) { // Do not use rejection cache for witness transactions or // witness-stripped transactions, as they can have been malleated. // See https://github.com/bitcoin/bitcoin/issues/8279 for details. assert(recentRejects); recentRejects->insert(tx.GetHash()); if (RecursiveDynamicUsage(*ptx) < 100000) { AddToCompactExtraTransactions(ptx); } } else if (tx.HasWitness() && RecursiveDynamicUsage(*ptx) < 100000) { AddToCompactExtraTransactions(ptx); } if (pfrom->fWhitelisted && gArgs.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY)) { // Always relay transactions received from whitelisted peers, even // if they were already in the mempool or rejected from it due // to policy, allowing the node to function as a gateway for // nodes hidden behind it. // // Never relay transactions that might result in being // disconnected (or banned). if (state.IsInvalid() && TxRelayMayResultInDisconnect(state)) { LogPrintf("Not relaying invalid transaction %s from whitelisted peer=%d (%s)\n", tx.GetHash().ToString(), pfrom->GetId(), FormatStateMessage(state)); } else { LogPrintf("Force relaying tx %s from whitelisted peer=%d\n", tx.GetHash().ToString(), pfrom->GetId()); RelayTransaction(tx.GetHash(), *connman); } } } for (const CTransactionRef& removedTx : lRemovedTxn) AddToCompactExtraTransactions(removedTx); // 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(), FormatStateMessage(state)); if (enable_bip61 && state.GetRejectCode() > 0 && state.GetRejectCode() < REJECT_INTERNAL) { // Never send AcceptToMemoryPool's internal codes over P2P connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::REJECT, strCommand, (unsigned char)state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), inv.hash)); } MaybePunishNode(pfrom->GetId(), state, /*via_compact_block*/ false); } return true; } if (strCommand == NetMsgType::CMPCTBLOCK) { // Ignore cmpctblock received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected cmpctblock message received from peer %d\n", pfrom->GetId()); return true; } 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()) connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), uint256())); return true; } if (!LookupBlockIndex(cmpctblock.header.GetHash())) { received_new_header = true; } } const CBlockIndex *pindex = nullptr; CValidationState state; if (!ProcessNewBlockHeaders({cmpctblock.header}, state, chainparams, &pindex)) { if (state.IsInvalid()) { MaybePunishNode(pfrom->GetId(), state, /*via_compact_block*/ true, "invalid header via cmpctblock"); return true; } } // 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 true; 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()); connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); } return true; } // If we're not close to tip yet, give up and let parallel block fetch work its magic if (!fAlreadyInFlight && !CanDirectFetch(chainparams.GetConsensus())) return true; if (IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus()) && !nodestate->fSupportsDesiredCmpctVersion) { // Don't bother trying to process compact blocks from v1 peers // after segwit activates. return true; } // 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(pfrom->GetId(), pindex->GetBlockHash(), pindex, &queuedBlockIt)) { if (!(*queuedBlockIt)->partialBlock) (*queuedBlockIt)->partialBlock.reset(new PartiallyDownloadedBlock(&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 true; } } PartiallyDownloadedBlock& partialBlock = *(*queuedBlockIt)->partialBlock; ReadStatus status = partialBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status == READ_STATUS_INVALID) { MarkBlockAsReceived(pindex->GetBlockHash()); // Reset in-flight state in case of whitelist Misbehaving(pfrom->GetId(), 100, strprintf("Peer %d sent us invalid compact block\n", pfrom->GetId())); return true; } 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()); connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); return true; } 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(); 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(&mempool); ReadStatus status = tempBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status != READ_STATUS_OK) { // TODO: don't ignore failures return true; } 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()); connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETDATA, vInv)); return true; } 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, nTimeReceived, chainparams, connman, interruptMsgProc, enable_bip61); 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 banned. return ProcessHeadersMessage(pfrom, connman, {cmpctblock.header}, chainparams, /*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. ProcessNewBlock(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 true; } if (strCommand == NetMsgType::BLOCKTXN) { // Ignore blocktxn received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected blocktxn message received from peer %d\n", pfrom->GetId()); return true; } 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 true; } 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 of whitelist Misbehaving(pfrom->GetId(), 100, strprintf("Peer %d sent us invalid compact block/non-matching block transactions\n", pfrom->GetId())); return true; } 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)); 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 DoS-ban 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, reject messages go out, etc. MarkBlockAsReceived(resp.blockhash); // it is now an empty pointer fBlockRead = true; // mapBlockSource is only used for sending reject messages and DoS scores, // 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. ProcessNewBlock(chainparams, pblock, /*fForceProcessing=*/true, &fNewBlock); if (fNewBlock) { pfrom->nLastBlockTime = GetTime(); } else { LOCK(cs_main); mapBlockSource.erase(pblock->GetHash()); } } return true; } if (strCommand == NetMsgType::HEADERS) { // Ignore headers received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected headers message received from peer %d\n", pfrom->GetId()); return true; } 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) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 20, strprintf("headers message size = %u", nCount)); return false; } 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, connman, headers, chainparams, /*via_compact_block=*/false); } if (strCommand == NetMsgType::BLOCK) { // Ignore block received while importing if (fImporting || fReindex) { LogPrint(BCLog::NET, "Unexpected block message received from peer %d\n", pfrom->GetId()); return true; } 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 sending reject messages and DoS scores, // so the race between here and cs_main in ProcessNewBlock is fine. mapBlockSource.emplace(hash, std::make_pair(pfrom->GetId(), true)); } bool fNewBlock = false; ProcessNewBlock(chainparams, pblock, forceProcessing, &fNewBlock); if (fNewBlock) { pfrom->nLastBlockTime = GetTime(); } else { LOCK(cs_main); mapBlockSource.erase(pblock->GetHash()); } return true; } if (strCommand == 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->fInbound) { LogPrint(BCLog::NET, "Ignoring \"getaddr\" from outbound connection. peer=%d\n", pfrom->GetId()); return true; } // 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 true; } pfrom->fSentAddr = true; pfrom->vAddrToSend.clear(); std::vector vAddr = connman->GetAddresses(); FastRandomContext insecure_rand; for (const CAddress &addr : vAddr) { if (!g_banman->IsBanned(addr)) { pfrom->PushAddress(addr, insecure_rand); } } return true; } if (strCommand == NetMsgType::MEMPOOL) { if (!(pfrom->GetLocalServices() & NODE_BLOOM) && !pfrom->fWhitelisted) { if (!pfrom->HasPermission(PF_NOBAN)) { LogPrint(BCLog::NET, "mempool request with bloom filters disabled, disconnect peer=%d\n", pfrom->GetId()); pfrom->fDisconnect = true; } return true; } if (connman->OutboundTargetReached(false) && !pfrom->fWhitelisted) { if (!pfrom->HasPermission(PF_NOBAN)) { LogPrint(BCLog::NET, "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom->GetId()); pfrom->fDisconnect = true; } return true; } LOCK(pfrom->cs_inventory); pfrom->fSendMempool = true; return true; } if (strCommand == NetMsgType::PING) { if (pfrom->nVersion > 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. connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::PONG, nonce)); } return true; } if (strCommand == NetMsgType::PONG) { int64_t pingUsecEnd = nTimeReceived; 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; int64_t pingUsecTime = pingUsecEnd - pfrom->nPingUsecStart; if (pingUsecTime > 0) { // Successful ping time measurement, replace previous pfrom->nPingUsecTime = pingUsecTime; pfrom->nMinPingUsecTime = std::min(pfrom->nMinPingUsecTime.load(), pingUsecTime); } 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 true; } if (strCommand == NetMsgType::FILTERLOAD) { CBloomFilter filter; vRecv >> filter; if (!filter.IsWithinSizeConstraints()) { // There is no excuse for sending a too-large filter LOCK(cs_main); Misbehaving(pfrom->GetId(), 100); } else { LOCK(pfrom->cs_filter); pfrom->pfilter.reset(new CBloomFilter(filter)); pfrom->pfilter->UpdateEmptyFull(); pfrom->fRelayTxes = true; } return true; } if (strCommand == NetMsgType::FILTERADD) { 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 { LOCK(pfrom->cs_filter); if (pfrom->pfilter) { pfrom->pfilter->insert(vData); } else { bad = true; } } if (bad) { LOCK(cs_main); Misbehaving(pfrom->GetId(), 100); } return true; } if (strCommand == NetMsgType::FILTERCLEAR) { LOCK(pfrom->cs_filter); if (pfrom->GetLocalServices() & NODE_BLOOM) { pfrom->pfilter.reset(new CBloomFilter()); } pfrom->fRelayTxes = true; return true; } if (strCommand == NetMsgType::FEEFILTER) { CAmount newFeeFilter = 0; vRecv >> newFeeFilter; if (MoneyRange(newFeeFilter)) { { LOCK(pfrom->cs_feeFilter); pfrom->minFeeFilter = newFeeFilter; } LogPrint(BCLog::NET, "received: feefilter of %s from peer=%d\n", CFeeRate(newFeeFilter).ToString(), pfrom->GetId()); } return true; } if (strCommand == NetMsgType::NOTFOUND) { // Remove the NOTFOUND transactions from the peer LOCK(cs_main); CNodeState *state = State(pfrom->GetId()); std::vector vInv; vRecv >> vInv; if (vInv.size() <= MAX_PEER_TX_IN_FLIGHT + MAX_BLOCKS_IN_TRANSIT_PER_PEER) { for (CInv &inv : vInv) { if (inv.type == MSG_TX || inv.type == MSG_WITNESS_TX) { // If we receive a NOTFOUND message for a txid we requested, erase // it from our data structures for this peer. auto in_flight_it = state->m_tx_download.m_tx_in_flight.find(inv.hash); if (in_flight_it == state->m_tx_download.m_tx_in_flight.end()) { // Skip any further work if this is a spurious NOTFOUND // message. continue; } state->m_tx_download.m_tx_in_flight.erase(in_flight_it); state->m_tx_download.m_tx_announced.erase(inv.hash); } } } return true; } // Ignore unknown commands for extensibility LogPrint(BCLog::NET, "Unknown command \"%s\" from peer=%d\n", SanitizeString(strCommand), pfrom->GetId()); return true; } bool PeerLogicValidation::SendRejectsAndCheckIfBanned(CNode* pnode, bool enable_bip61) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { AssertLockHeld(cs_main); CNodeState &state = *State(pnode->GetId()); if (enable_bip61) { for (const CBlockReject& reject : state.rejects) { connman->PushMessage(pnode, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, std::string(NetMsgType::BLOCK), reject.chRejectCode, reject.strRejectReason, reject.hashBlock)); } } state.rejects.clear(); if (state.fShouldBan) { state.fShouldBan = false; if (pnode->fWhitelisted) LogPrintf("Warning: not punishing whitelisted peer %s!\n", pnode->addr.ToString()); else if (pnode->m_manual_connection) LogPrintf("Warning: not punishing manually-connected peer %s!\n", pnode->addr.ToString()); else if (pnode->addr.IsLocal()) { // Disconnect but don't ban _this_ local node LogPrintf("Warning: disconnecting but not banning local peer %s!\n", pnode->addr.ToString()); pnode->fDisconnect = true; } else { // Disconnect and ban all nodes sharing the address if (m_banman) { m_banman->Ban(pnode->addr, BanReasonNodeMisbehaving); } connman->DisconnectNode(pnode->addr); } return true; } return false; } bool PeerLogicValidation::ProcessMessages(CNode* pfrom, std::atomic& interruptMsgProc) { const CChainParams& chainparams = Params(); // // Message format // (4) message start // (12) command // (4) size // (4) checksum // (x) data // bool fMoreWork = false; if (!pfrom->vRecvGetData.empty()) ProcessGetData(pfrom, chainparams, connman, interruptMsgProc); if (!pfrom->orphan_work_set.empty()) { std::list removed_txn; LOCK2(cs_main, g_cs_orphans); ProcessOrphanTx(connman, pfrom->orphan_work_set, removed_txn); for (const CTransactionRef& removedTx : removed_txn) { AddToCompactExtraTransactions(removedTx); } } if (pfrom->fDisconnect) return false; // this maintains the order of responses // and prevents vRecvGetData to grow unbounded if (!pfrom->vRecvGetData.empty()) return true; if (!pfrom->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().vRecv.size() + CMessageHeader::HEADER_SIZE; pfrom->fPauseRecv = pfrom->nProcessQueueSize > connman->GetReceiveFloodSize(); fMoreWork = !pfrom->vProcessMsg.empty(); } CNetMessage& msg(msgs.front()); msg.SetVersion(pfrom->GetRecvVersion()); // Scan for message start if (memcmp(msg.hdr.pchMessageStart, chainparams.MessageStart(), CMessageHeader::MESSAGE_START_SIZE) != 0) { LogPrint(BCLog::NET, "PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%d\n", SanitizeString(msg.hdr.GetCommand()), pfrom->GetId()); pfrom->fDisconnect = true; return false; } // Read header CMessageHeader& hdr = msg.hdr; if (!hdr.IsValid(chainparams.MessageStart())) { LogPrint(BCLog::NET, "PROCESSMESSAGE: ERRORS IN HEADER %s peer=%d\n", SanitizeString(hdr.GetCommand()), pfrom->GetId()); return fMoreWork; } std::string strCommand = hdr.GetCommand(); // Message size unsigned int nMessageSize = hdr.nMessageSize; // Checksum CDataStream& vRecv = msg.vRecv; const uint256& hash = msg.GetMessageHash(); if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) { LogPrint(BCLog::NET, "%s(%s, %u bytes): CHECKSUM ERROR expected %s was %s\n", __func__, SanitizeString(strCommand), nMessageSize, HexStr(hash.begin(), hash.begin()+CMessageHeader::CHECKSUM_SIZE), HexStr(hdr.pchChecksum, hdr.pchChecksum+CMessageHeader::CHECKSUM_SIZE)); return fMoreWork; } // Process message bool fRet = false; try { fRet = ProcessMessage(pfrom, strCommand, vRecv, msg.nTime, chainparams, connman, interruptMsgProc, m_enable_bip61); if (interruptMsgProc) return false; if (!pfrom->vRecvGetData.empty()) fMoreWork = true; } catch (const std::ios_base::failure& e) { if (m_enable_bip61) { connman->PushMessage(pfrom, CNetMsgMaker(INIT_PROTO_VERSION).Make(NetMsgType::REJECT, strCommand, REJECT_MALFORMED, std::string("error parsing message"))); } if (strstr(e.what(), "end of data")) { // Allow exceptions from under-length message on vRecv LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught, normally caused by a message being shorter than its stated length\n", __func__, SanitizeString(strCommand), nMessageSize, e.what()); } else if (strstr(e.what(), "size too large")) { // Allow exceptions from over-long size LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what()); } else if (strstr(e.what(), "non-canonical ReadCompactSize()")) { // Allow exceptions from non-canonical encoding LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what()); } else if (strstr(e.what(), "Superfluous witness record")) { // Allow exceptions from illegal witness encoding LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what()); } else if (strstr(e.what(), "Unknown transaction optional data")) { // Allow exceptions from unknown witness encoding LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' caught\n", __func__, SanitizeString(strCommand), nMessageSize, e.what()); } else { PrintExceptionContinue(&e, "ProcessMessages()"); } } catch (const std::exception& e) { PrintExceptionContinue(&e, "ProcessMessages()"); } catch (...) { PrintExceptionContinue(nullptr, "ProcessMessages()"); } if (!fRet) { LogPrint(BCLog::NET, "%s(%s, %u bytes) FAILED peer=%d\n", __func__, SanitizeString(strCommand), nMessageSize, pfrom->GetId()); } LOCK(cs_main); SendRejectsAndCheckIfBanned(pfrom, m_enable_bip61); return fMoreWork; } void PeerLogicValidation::ConsiderEviction(CNode *pto, int64_t time_in_seconds) { AssertLockHeld(cs_main); CNodeState &state = *State(pto->GetId()); const CNetMsgMaker msgMaker(pto->GetSendVersion()); if (!state.m_chain_sync.m_protect && IsOutboundDisconnectionCandidate(pto) && 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()); 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 PeerLogicValidation::EvictExtraOutboundPeers(int64_t time_in_seconds) { // Check whether we have too many outbound peers int extra_peers = connman->GetExtraOutboundCount(); if (extra_peers > 0) { // If we have more outbound peers than we target, disconnect one. // Pick the outbound 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(); connman->ForEachNode([&](CNode* pnode) { AssertLockHeld(cs_main); // Ignore non-outbound peers, or nodes marked for disconnect already if (!IsOutboundDisconnectionCandidate(pnode) || 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 = connman->ForNode(worst_peer, [&](CNode *pnode) { 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. connman->SetTryNewOutboundPeer(false); } } } } void PeerLogicValidation::CheckForStaleTipAndEvictPeers(const Consensus::Params &consensusParams) { LOCK(cs_main); if (connman == nullptr) return; 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 && connman->GetNetworkActive() && connman->GetUseAddrmanOutgoing() && TipMayBeStale(consensusParams)) { 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); connman->SetTryNewOutboundPeer(true); } else if (connman->GetTryNewOutboundPeer()) { connman->SetTryNewOutboundPeer(false); } m_stale_tip_check_time = time_in_seconds + STALE_CHECK_INTERVAL; } } namespace { class CompareInvMempoolOrder { CTxMemPool *mp; public: explicit CompareInvMempoolOrder(CTxMemPool *_mempool) { mp = _mempool; } 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); } }; } bool PeerLogicValidation::SendMessages(CNode* pto) { const Consensus::Params& consensusParams = Params().GetConsensus(); { // 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->GetSendVersion()); // // Message: ping // bool pingSend = false; if (pto->fPingQueued) { // RPC ping request by user pingSend = true; } if (pto->nPingNonceSent == 0 && pto->nPingUsecStart + PING_INTERVAL * 1000000 < GetTimeMicros()) { // 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->nPingUsecStart = GetTimeMicros(); if (pto->nVersion > BIP0031_VERSION) { pto->nPingNonceSent = nonce; 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; connman->PushMessage(pto, msgMaker.Make(NetMsgType::PING)); } } TRY_LOCK(cs_main, lockMain); // Acquire cs_main for IsInitialBlockDownload() and CNodeState() if (!lockMain) return true; if (SendRejectsAndCheckIfBanned(pto, m_enable_bip61)) return true; CNodeState &state = *State(pto->GetId()); // Address refresh broadcast int64_t nNow = GetTimeMicros(); if (!::ChainstateActive().IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) { AdvertiseLocal(pto); pto->nNextLocalAddrSend = PoissonNextSend(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL); } // // Message: addr // if (pto->nNextAddrSend < nNow) { pto->nNextAddrSend = PoissonNextSend(nNow, AVG_ADDRESS_BROADCAST_INTERVAL); std::vector vAddr; vAddr.reserve(pto->vAddrToSend.size()); for (const CAddress& addr : pto->vAddrToSend) { if (!pto->addrKnown.contains(addr.GetKey())) { pto->addrKnown.insert(addr.GetKey()); vAddr.push_back(addr); // receiver rejects addr messages larger than 1000 if (vAddr.size() >= 1000) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::ADDR, vAddr)); vAddr.clear(); } } } pto->vAddrToSend.clear(); if (!vAddr.empty()) connman->PushMessage(pto, msgMaker.Make(NetMsgType::ADDR, 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->fOneShot); // 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 = GetTimeMicros() + 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); 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) connman->PushMessage(pto, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, *most_recent_compact_block)); else { CBlockHeaderAndShortTxIDs cmpctblock(*most_recent_block, state.fWantsCmpctWitness); 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); 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()); } 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->PushInventory(CInv(MSG_BLOCK, 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) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); vInv.clear(); } } pto->vInventoryBlockToSend.clear(); // Check whether periodic sends should happen bool fSendTrickle = pto->fWhitelisted; if (pto->nNextInvSend < nNow) { fSendTrickle = true; if (pto->fInbound) { pto->nNextInvSend = connman->PoissonNextSendInbound(nNow, INVENTORY_BROADCAST_INTERVAL); } else { // Use half the delay for outbound peers, as there is less privacy concern for them. pto->nNextInvSend = PoissonNextSend(nNow, INVENTORY_BROADCAST_INTERVAL >> 1); } } // Time to send but the peer has requested we not relay transactions. if (fSendTrickle) { LOCK(pto->cs_filter); if (!pto->fRelayTxes) pto->setInventoryTxToSend.clear(); } // Respond to BIP35 mempool requests if (fSendTrickle && pto->fSendMempool) { auto vtxinfo = mempool.infoAll(); pto->fSendMempool = false; CAmount filterrate = 0; { LOCK(pto->cs_feeFilter); filterrate = pto->minFeeFilter; } LOCK(pto->cs_filter); for (const auto& txinfo : vtxinfo) { const uint256& hash = txinfo.tx->GetHash(); CInv inv(MSG_TX, hash); pto->setInventoryTxToSend.erase(hash); if (filterrate) { if (txinfo.feeRate.GetFeePerK() < filterrate) continue; } if (pto->pfilter) { if (!pto->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue; } pto->filterInventoryKnown.insert(hash); vInv.push_back(inv); if (vInv.size() == MAX_INV_SZ) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); vInv.clear(); } } pto->timeLastMempoolReq = GetTime(); } // Determine transactions to relay if (fSendTrickle) { // Produce a vector with all candidates for sending std::vector::iterator> vInvTx; vInvTx.reserve(pto->setInventoryTxToSend.size()); for (std::set::iterator it = pto->setInventoryTxToSend.begin(); it != pto->setInventoryTxToSend.end(); it++) { vInvTx.push_back(it); } CAmount filterrate = 0; { LOCK(pto->cs_feeFilter); filterrate = pto->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(&mempool); 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->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; // Remove it from the to-be-sent set pto->setInventoryTxToSend.erase(it); // Check if not in the filter already if (pto->filterInventoryKnown.contains(hash)) { continue; } // Not in the mempool anymore? don't bother sending it. auto txinfo = mempool.info(hash); if (!txinfo.tx) { continue; } if (filterrate && txinfo.feeRate.GetFeePerK() < filterrate) { continue; } if (pto->pfilter && !pto->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue; // Send vInv.push_back(CInv(MSG_TX, hash)); nRelayedTransactions++; { // Expire old relay messages while (!vRelayExpiration.empty() && vRelayExpiration.front().first < nNow) { mapRelay.erase(vRelayExpiration.front().second); vRelayExpiration.pop_front(); } auto ret = mapRelay.insert(std::make_pair(hash, std::move(txinfo.tx))); if (ret.second) { vRelayExpiration.push_back(std::make_pair(nNow + 15 * 60 * 1000000, ret.first)); } } if (vInv.size() == MAX_INV_SZ) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); vInv.clear(); } pto->filterInventoryKnown.insert(hash); } } } if (!vInv.empty()) connman->PushMessage(pto, msgMaker.Make(NetMsgType::INV, vInv)); // Detect whether we're stalling const auto current_time = GetTime(); // nNow is the current system time (GetTimeMicros is not mockable) and // should be replaced by the mockable current_time eventually nNow = GetTimeMicros(); if (state.nStallingSince && state.nStallingSince < nNow - 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 (nNow > 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 (nNow > state.nHeadersSyncTimeout && nSyncStarted == 1 && (nPreferredDownload - state.fPreferredDownload >= 1)) { // Disconnect a (non-whitelisted) peer 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->fWhitelisted) { LogPrintf("Timeout downloading headers from peer=%d, disconnecting\n", pto->GetId()); pto->fDisconnect = true; return true; } else { LogPrintf("Timeout downloading headers from whitelisted 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(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 = nNow; LogPrint(BCLog::NET, "Stall started peer=%d\n", staller); } } } // // Message: getdata (non-blocks) // // For robustness, expire old requests after a long timeout, so that // we can resume downloading transactions from a peer even if they // were unresponsive in the past. // Eventually we should consider disconnecting peers, but this is // conservative. if (state.m_tx_download.m_check_expiry_timer <= current_time) { for (auto it=state.m_tx_download.m_tx_in_flight.begin(); it != state.m_tx_download.m_tx_in_flight.end();) { if (it->second <= current_time - TX_EXPIRY_INTERVAL) { LogPrint(BCLog::NET, "timeout of inflight tx %s from peer=%d\n", it->first.ToString(), pto->GetId()); state.m_tx_download.m_tx_announced.erase(it->first); state.m_tx_download.m_tx_in_flight.erase(it++); } else { ++it; } } // On average, we do this check every TX_EXPIRY_INTERVAL. Randomize // so that we're not doing this for all peers at the same time. state.m_tx_download.m_check_expiry_timer = current_time + TX_EXPIRY_INTERVAL / 2 + GetRandMicros(TX_EXPIRY_INTERVAL); } auto& tx_process_time = state.m_tx_download.m_tx_process_time; while (!tx_process_time.empty() && tx_process_time.begin()->first <= current_time && state.m_tx_download.m_tx_in_flight.size() < MAX_PEER_TX_IN_FLIGHT) { const uint256 txid = tx_process_time.begin()->second; // Erase this entry from tx_process_time (it may be added back for // processing at a later time, see below) tx_process_time.erase(tx_process_time.begin()); CInv inv(MSG_TX | GetFetchFlags(pto), txid); if (!AlreadyHave(inv)) { // If this transaction was last requested more than 1 minute ago, // then request. const auto last_request_time = GetTxRequestTime(inv.hash); if (last_request_time <= current_time - GETDATA_TX_INTERVAL) { LogPrint(BCLog::NET, "Requesting %s peer=%d\n", inv.ToString(), pto->GetId()); vGetData.push_back(inv); if (vGetData.size() >= MAX_GETDATA_SZ) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData)); vGetData.clear(); } UpdateTxRequestTime(inv.hash, current_time); state.m_tx_download.m_tx_in_flight.emplace(inv.hash, current_time); } else { // This transaction is in flight from someone else; queue // up processing to happen after the download times out // (with a slight delay for inbound peers, to prefer // requests to outbound peers). const auto next_process_time = CalculateTxGetDataTime(txid, current_time, !state.fPreferredDownload); tx_process_time.emplace(next_process_time, txid); } } else { // We have already seen this transaction, no need to download. state.m_tx_download.m_tx_announced.erase(inv.hash); state.m_tx_download.m_tx_in_flight.erase(inv.hash); } } if (!vGetData.empty()) connman->PushMessage(pto, msgMaker.Make(NetMsgType::GETDATA, vGetData)); // // Message: feefilter // // We don't want white listed peers to filter txs to us if we have -whitelistforcerelay if (pto->nVersion >= FEEFILTER_VERSION && gArgs.GetBoolArg("-feefilter", DEFAULT_FEEFILTER) && !(pto->fWhitelisted && gArgs.GetBoolArg("-whitelistforcerelay", DEFAULT_WHITELISTFORCERELAY))) { CAmount currentFilter = mempool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK(); int64_t timeNow = GetTimeMicros(); if (timeNow > pto->nextSendTimeFeeFilter) { static CFeeRate default_feerate(DEFAULT_MIN_RELAY_TX_FEE); static FeeFilterRounder filterRounder(default_feerate); CAmount filterToSend = filterRounder.round(currentFilter); // We always have a fee filter of at least minRelayTxFee filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK()); if (filterToSend != pto->lastSentFeeFilter) { connman->PushMessage(pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend)); pto->lastSentFeeFilter = filterToSend; } pto->nextSendTimeFeeFilter = PoissonNextSend(timeNow, 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 (timeNow + MAX_FEEFILTER_CHANGE_DELAY * 1000000 < pto->nextSendTimeFeeFilter && (currentFilter < 3 * pto->lastSentFeeFilter / 4 || currentFilter > 4 * pto->lastSentFeeFilter / 3)) { pto->nextSendTimeFeeFilter = timeNow + GetRandInt(MAX_FEEFILTER_CHANGE_DELAY) * 1000000; } } } return true; } class CNetProcessingCleanup { public: CNetProcessingCleanup() {} ~CNetProcessingCleanup() { // orphan transactions mapOrphanTransactions.clear(); mapOrphanTransactionsByPrev.clear(); } }; static CNetProcessingCleanup instance_of_cnetprocessingcleanup;