// Copyright (c) 2009-2010 Satoshi Nakamoto // Copyright (c) 2009-2022 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** Headers download timeout. * Timeout = base + per_header * (expected number of headers) */ static constexpr auto HEADERS_DOWNLOAD_TIMEOUT_BASE = 15min; static constexpr auto HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1ms; /** How long to wait for a peer to respond to a getheaders request */ static constexpr auto HEADERS_RESPONSE_TIME{2min}; /** 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 */ static constexpr auto CHAIN_SYNC_TIMEOUT{20min}; /** How frequently to check for stale tips */ static constexpr auto STALE_CHECK_INTERVAL{10min}; /** How frequently to check for extra outbound peers and disconnect */ static constexpr auto EXTRA_PEER_CHECK_INTERVAL{45s}; /** Minimum time an outbound-peer-eviction candidate must be connected for, in order to evict */ static constexpr auto MINIMUM_CONNECT_TIME{30s}; /** SHA256("main address relay")[0:8] */ static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL; /// Age after which a stale block will no longer be served if requested as /// protection against fingerprinting. Set to one month, denominated in seconds. static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60; /// Age after which a block is considered historical for purposes of rate /// limiting block relay. Set to one week, denominated in seconds. static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60; /** Time between pings automatically sent out for latency probing and keepalive */ static constexpr auto PING_INTERVAL{2min}; /** The maximum number of entries in a locator */ static const unsigned int MAX_LOCATOR_SZ = 101; /** The maximum number of entries in an 'inv' protocol message */ static const unsigned int MAX_INV_SZ = 50000; /** Maximum number of in-flight transaction requests from a peer. It is not a hard limit, but the threshold at which * point the OVERLOADED_PEER_TX_DELAY kicks in. */ static constexpr int32_t MAX_PEER_TX_REQUEST_IN_FLIGHT = 100; /** Maximum number of transactions to consider for requesting, per peer. It provides a reasonable DoS limit to * per-peer memory usage spent on announcements, while covering peers continuously sending INVs at the maximum * rate (by our own policy, see INVENTORY_BROADCAST_PER_SECOND) for several minutes, while not receiving * the actual transaction (from any peer) in response to requests for them. */ static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 5000; /** How long to delay requesting transactions via txids, if we have wtxid-relaying peers */ static constexpr auto TXID_RELAY_DELAY{2s}; /** How long to delay requesting transactions from non-preferred peers */ static constexpr auto NONPREF_PEER_TX_DELAY{2s}; /** How long to delay requesting transactions from overloaded peers (see MAX_PEER_TX_REQUEST_IN_FLIGHT). */ static constexpr auto OVERLOADED_PEER_TX_DELAY{2s}; /** How long to wait before downloading a transaction from an additional peer */ static constexpr auto GETDATA_TX_INTERVAL{60s}; /** Limit to avoid sending big packets. Not used in processing incoming GETDATA for compatibility */ static const unsigned int MAX_GETDATA_SZ = 1000; /** Number of blocks that can be requested at any given time from a single peer. */ static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16; /** Default time during which a peer must stall block download progress before being disconnected. * the actual timeout is increased temporarily if peers are disconnected for hitting the timeout */ static constexpr auto BLOCK_STALLING_TIMEOUT_DEFAULT{2s}; /** Maximum timeout for stalling block download. */ static constexpr auto BLOCK_STALLING_TIMEOUT_MAX{64s}; /** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends * less than this number, we reached its tip. Changing this value is a protocol upgrade. */ static const unsigned int MAX_HEADERS_RESULTS = 2000; /** Maximum depth of blocks we're willing to serve as compact blocks to peers * when requested. For older blocks, a regular BLOCK response will be sent. */ static const int MAX_CMPCTBLOCK_DEPTH = 5; /** Maximum depth of blocks we're willing to respond to GETBLOCKTXN requests for. */ static const int MAX_BLOCKTXN_DEPTH = 10; /** Size of the "block download window": how far ahead of our current height do we fetch? * Larger windows tolerate larger download speed differences between peer, but increase the potential * degree of disordering of blocks on disk (which make reindexing and pruning harder). We'll probably * want to make this a per-peer adaptive value at some point. */ static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024; /** Block download timeout base, expressed in multiples of the block interval (i.e. 10 min) */ static constexpr double BLOCK_DOWNLOAD_TIMEOUT_BASE = 1; /** Additional block download timeout per parallel downloading peer (i.e. 5 min) */ static constexpr double BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 0.5; /** Maximum number of headers to announce when relaying blocks with headers message.*/ static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8; /** Maximum number of unconnecting headers announcements before DoS score */ static const int MAX_NUM_UNCONNECTING_HEADERS_MSGS = 10; /** Minimum blocks required to signal NODE_NETWORK_LIMITED */ static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288; /** Window, in blocks, for connecting to NODE_NETWORK_LIMITED peers */ static const unsigned int NODE_NETWORK_LIMITED_ALLOW_CONN_BLOCKS = 144; /** Average delay between local address broadcasts */ static constexpr auto AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24h}; /** Average delay between peer address broadcasts */ static constexpr auto AVG_ADDRESS_BROADCAST_INTERVAL{30s}; /** Delay between rotating the peers we relay a particular address to */ static constexpr auto ROTATE_ADDR_RELAY_DEST_INTERVAL{24h}; /** Average delay between trickled inventory transmissions for inbound peers. * Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */ static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL{5s}; /** Average delay between trickled inventory transmissions for outbound peers. * Use a smaller delay as there is less privacy concern for them. * Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */ static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL{2s}; /** Maximum rate of inventory items to send per second. * Limits the impact of low-fee transaction floods. */ static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND = 7; /** Target number of tx inventory items to send per transmission. */ static constexpr unsigned int INVENTORY_BROADCAST_TARGET = INVENTORY_BROADCAST_PER_SECOND * count_seconds(INBOUND_INVENTORY_BROADCAST_INTERVAL); /** Maximum number of inventory items to send per transmission. */ static constexpr unsigned int INVENTORY_BROADCAST_MAX = 1000; static_assert(INVENTORY_BROADCAST_MAX >= INVENTORY_BROADCAST_TARGET, "INVENTORY_BROADCAST_MAX too low"); static_assert(INVENTORY_BROADCAST_MAX <= MAX_PEER_TX_ANNOUNCEMENTS, "INVENTORY_BROADCAST_MAX too high"); /** Average delay between feefilter broadcasts in seconds. */ static constexpr auto AVG_FEEFILTER_BROADCAST_INTERVAL{10min}; /** Maximum feefilter broadcast delay after significant change. */ static constexpr auto MAX_FEEFILTER_CHANGE_DELAY{5min}; /** Maximum number of compact filters that may be requested with one getcfilters. See BIP 157. */ static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000; /** Maximum number of cf hashes that may be requested with one getcfheaders. See BIP 157. */ static constexpr uint32_t MAX_GETCFHEADERS_SIZE = 2000; /** the maximum percentage of addresses from our addrman to return in response to a getaddr message. */ static constexpr size_t MAX_PCT_ADDR_TO_SEND = 23; /** The maximum number of address records permitted in an ADDR message. */ static constexpr size_t MAX_ADDR_TO_SEND{1000}; /** The maximum rate of address records we're willing to process on average. Can be bypassed using * the NetPermissionFlags::Addr permission. */ static constexpr double MAX_ADDR_RATE_PER_SECOND{0.1}; /** The soft limit of the address processing token bucket (the regular MAX_ADDR_RATE_PER_SECOND * based increments won't go above this, but the MAX_ADDR_TO_SEND increment following GETADDR * is exempt from this limit). */ static constexpr size_t MAX_ADDR_PROCESSING_TOKEN_BUCKET{MAX_ADDR_TO_SEND}; /** The compactblocks version we support. See BIP 152. */ static constexpr uint64_t CMPCTBLOCKS_VERSION{2}; // Internal stuff namespace { /** Blocks that are in flight, and that are in the queue to be downloaded. */ struct QueuedBlock { /** BlockIndex. We must have this since we only request blocks when we've already validated the header. */ const CBlockIndex* pindex; /** Optional, used for CMPCTBLOCK downloads */ std::unique_ptr partialBlock; }; /** * Data structure for an individual peer. This struct is not protected by * cs_main since it does not contain validation-critical data. * * Memory is owned by shared pointers and this object is destructed when * the refcount drops to zero. * * Mutexes inside this struct must not be held when locking m_peer_mutex. * * TODO: move most members from CNodeState to this structure. * TODO: move remaining application-layer data members from CNode to this structure. */ struct Peer { /** Same id as the CNode object for this peer */ const NodeId m_id{0}; /** Services we offered to this peer. * * This is supplied by CConnman during peer initialization. It's const * because there is no protocol defined for renegotiating services * initially offered to a peer. The set of local services we offer should * not change after initialization. * * An interesting example of this is NODE_NETWORK and initial block * download: a node which starts up from scratch doesn't have any blocks * to serve, but still advertises NODE_NETWORK because it will eventually * fulfill this role after IBD completes. P2P code is written in such a * way that it can gracefully handle peers who don't make good on their * service advertisements. */ const ServiceFlags m_our_services; /** Services this peer offered to us. */ std::atomic m_their_services{NODE_NONE}; /** Protects misbehavior data members */ Mutex m_misbehavior_mutex; /** Accumulated misbehavior score for this peer */ int m_misbehavior_score GUARDED_BY(m_misbehavior_mutex){0}; /** Whether this peer should be disconnected and marked as discouraged (unless it has NetPermissionFlags::NoBan permission). */ bool m_should_discourage GUARDED_BY(m_misbehavior_mutex){false}; /** Protects block inventory data members */ Mutex m_block_inv_mutex; /** List of blocks that we'll announce via an `inv` message. * There is no final sorting before sending, as they are always sent * immediately and in the order requested. */ std::vector m_blocks_for_inv_relay GUARDED_BY(m_block_inv_mutex); /** Unfiltered list of blocks that we'd like to announce via a `headers` * message. If we can't announce via a `headers` message, we'll fall back to * announcing via `inv`. */ std::vector m_blocks_for_headers_relay GUARDED_BY(m_block_inv_mutex); /** The final block hash that we sent in an `inv` message to this peer. * When the peer requests this block, we send an `inv` message to trigger * the peer to request the next sequence of block hashes. * Most peers use headers-first syncing, which doesn't use this mechanism */ uint256 m_continuation_block GUARDED_BY(m_block_inv_mutex) {}; /** This peer's reported block height when we connected */ std::atomic m_starting_height{-1}; /** The pong reply we're expecting, or 0 if no pong expected. */ std::atomic m_ping_nonce_sent{0}; /** When the last ping was sent, or 0 if no ping was ever sent */ std::atomic m_ping_start{0us}; /** Whether a ping has been requested by the user */ std::atomic m_ping_queued{false}; /** Whether this peer relays txs via wtxid */ std::atomic m_wtxid_relay{false}; /** The feerate in the most recent BIP133 `feefilter` message sent to the peer. * It is *not* a p2p protocol violation for the peer to send us * transactions with a lower fee rate than this. See BIP133. */ CAmount m_fee_filter_sent GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0}; /** Timestamp after which we will send the next BIP133 `feefilter` message * to the peer. */ std::chrono::microseconds m_next_send_feefilter GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0}; struct TxRelay { mutable RecursiveMutex m_bloom_filter_mutex; /** Whether we relay transactions to this peer. */ bool m_relay_txs GUARDED_BY(m_bloom_filter_mutex){false}; /** A bloom filter for which transactions to announce to the peer. See BIP37. */ std::unique_ptr m_bloom_filter PT_GUARDED_BY(m_bloom_filter_mutex) GUARDED_BY(m_bloom_filter_mutex){nullptr}; mutable RecursiveMutex m_tx_inventory_mutex; /** A filter of all the (w)txids that the peer has announced to * us or we have announced to the peer. We use this to avoid announcing * the same (w)txid to a peer that already has the transaction. */ CRollingBloomFilter m_tx_inventory_known_filter GUARDED_BY(m_tx_inventory_mutex){50000, 0.000001}; /** Set of transaction ids we still have to announce (txid for * non-wtxid-relay peers, wtxid for wtxid-relay peers). We use the * mempool to sort transactions in dependency order before relay, so * this does not have to be sorted. */ std::set m_tx_inventory_to_send GUARDED_BY(m_tx_inventory_mutex); /** Whether the peer has requested us to send our complete mempool. Only * permitted if the peer has NetPermissionFlags::Mempool or we advertise * NODE_BLOOM. See BIP35. */ bool m_send_mempool GUARDED_BY(m_tx_inventory_mutex){false}; /** The next time after which we will send an `inv` message containing * transaction announcements to this peer. */ std::chrono::microseconds m_next_inv_send_time GUARDED_BY(m_tx_inventory_mutex){0}; /** The mempool sequence num at which we sent the last `inv` message to this peer. * Can relay txs with lower sequence numbers than this (see CTxMempool::info_for_relay). */ uint64_t m_last_inv_sequence GUARDED_BY(NetEventsInterface::g_msgproc_mutex){1}; /** Minimum fee rate with which to filter transaction announcements to this node. See BIP133. */ std::atomic m_fee_filter_received{0}; }; /* Initializes a TxRelay struct for this peer. Can be called at most once for a peer. */ TxRelay* SetTxRelay() EXCLUSIVE_LOCKS_REQUIRED(!m_tx_relay_mutex) { LOCK(m_tx_relay_mutex); Assume(!m_tx_relay); m_tx_relay = std::make_unique(); return m_tx_relay.get(); }; TxRelay* GetTxRelay() EXCLUSIVE_LOCKS_REQUIRED(!m_tx_relay_mutex) { return WITH_LOCK(m_tx_relay_mutex, return m_tx_relay.get()); }; /** A vector of addresses to send to the peer, limited to MAX_ADDR_TO_SEND. */ std::vector m_addrs_to_send GUARDED_BY(NetEventsInterface::g_msgproc_mutex); /** Probabilistic filter to track recent addr messages relayed with this * peer. Used to avoid relaying redundant addresses to this peer. * * We initialize this filter for outbound peers (other than * block-relay-only connections) or when an inbound peer sends us an * address related message (ADDR, ADDRV2, GETADDR). * * Presence of this filter must correlate with m_addr_relay_enabled. **/ std::unique_ptr m_addr_known GUARDED_BY(NetEventsInterface::g_msgproc_mutex); /** Whether we are participating in address relay with this connection. * * We set this bool to true for outbound peers (other than * block-relay-only connections), or when an inbound peer sends us an * address related message (ADDR, ADDRV2, GETADDR). * * We use this bool to decide whether a peer is eligible for gossiping * addr messages. This avoids relaying to peers that are unlikely to * forward them, effectively blackholing self announcements. Reasons * peers might support addr relay on the link include that they connected * to us as a block-relay-only peer or they are a light client. * * This field must correlate with whether m_addr_known has been * initialized.*/ std::atomic_bool m_addr_relay_enabled{false}; /** Whether a getaddr request to this peer is outstanding. */ bool m_getaddr_sent GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false}; /** Guards address sending timers. */ mutable Mutex m_addr_send_times_mutex; /** Time point to send the next ADDR message to this peer. */ std::chrono::microseconds m_next_addr_send GUARDED_BY(m_addr_send_times_mutex){0}; /** Time point to possibly re-announce our local address to this peer. */ std::chrono::microseconds m_next_local_addr_send GUARDED_BY(m_addr_send_times_mutex){0}; /** Whether the peer has signaled support for receiving ADDRv2 (BIP155) * messages, indicating a preference to receive ADDRv2 instead of ADDR ones. */ std::atomic_bool m_wants_addrv2{false}; /** Whether this peer has already sent us a getaddr message. */ bool m_getaddr_recvd GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false}; /** Number of addresses that can be processed from this peer. Start at 1 to * permit self-announcement. */ double m_addr_token_bucket GUARDED_BY(NetEventsInterface::g_msgproc_mutex){1.0}; /** When m_addr_token_bucket was last updated */ std::chrono::microseconds m_addr_token_timestamp GUARDED_BY(NetEventsInterface::g_msgproc_mutex){GetTime()}; /** Total number of addresses that were dropped due to rate limiting. */ std::atomic m_addr_rate_limited{0}; /** Total number of addresses that were processed (excludes rate-limited ones). */ std::atomic m_addr_processed{0}; /** Whether we've sent this peer a getheaders in response to an inv prior to initial-headers-sync completing */ bool m_inv_triggered_getheaders_before_sync GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false}; /** Protects m_getdata_requests **/ Mutex m_getdata_requests_mutex; /** Work queue of items requested by this peer **/ std::deque m_getdata_requests GUARDED_BY(m_getdata_requests_mutex); /** Time of the last getheaders message to this peer */ NodeClock::time_point m_last_getheaders_timestamp GUARDED_BY(NetEventsInterface::g_msgproc_mutex){}; /** Protects m_headers_sync **/ Mutex m_headers_sync_mutex; /** Headers-sync state for this peer (eg for initial sync, or syncing large * reorgs) **/ std::unique_ptr m_headers_sync PT_GUARDED_BY(m_headers_sync_mutex) GUARDED_BY(m_headers_sync_mutex) {}; /** Whether we've sent our peer a sendheaders message. **/ std::atomic m_sent_sendheaders{false}; /** Length of current-streak of unconnecting headers announcements */ int m_num_unconnecting_headers_msgs GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0}; /** When to potentially disconnect peer for stalling headers download */ std::chrono::microseconds m_headers_sync_timeout GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0us}; /** Whether this peer wants invs or headers (when possible) for block announcements */ bool m_prefers_headers GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false}; /** Time offset computed during the version handshake based on the * timestamp the peer sent in the version message. */ std::atomic m_time_offset{0s}; explicit Peer(NodeId id, ServiceFlags our_services) : m_id{id} , m_our_services{our_services} {} private: mutable Mutex m_tx_relay_mutex; /** Transaction relay data. May be a nullptr. */ std::unique_ptr m_tx_relay GUARDED_BY(m_tx_relay_mutex); }; using PeerRef = std::shared_ptr; /** * 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 best known block we know this peer has announced. const CBlockIndex* pindexBestKnownBlock{nullptr}; //! The hash of the last unknown block this peer has announced. uint256 hashLastUnknownBlock{}; //! The last full block we both have. const CBlockIndex* pindexLastCommonBlock{nullptr}; //! The best header we have sent our peer. const CBlockIndex* pindexBestHeaderSent{nullptr}; //! Whether we've started headers synchronization with this peer. bool fSyncStarted{false}; //! Since when we're stalling block download progress (in microseconds), or 0. std::chrono::microseconds m_stalling_since{0us}; std::list vBlocksInFlight; //! When the first entry in vBlocksInFlight started downloading. Don't care when vBlocksInFlight is empty. std::chrono::microseconds m_downloading_since{0us}; //! Whether we consider this a preferred download peer. bool fPreferredDownload{false}; /** Whether this peer wants invs or cmpctblocks (when possible) for block announcements. */ bool m_requested_hb_cmpctblocks{false}; /** Whether this peer will send us cmpctblocks if we request them. */ bool m_provides_cmpctblocks{false}; /** State used to enforce CHAIN_SYNC_TIMEOUT and EXTRA_PEER_CHECK_INTERVAL logic. * * Both are only in effect for outbound, non-manual, non-protected connections. * Any peer protected (m_protect = true) is not chosen for eviction. A peer is * marked as protected if all of these are true: * - its connection type is IsBlockOnlyConn() == false * - it gave us a valid connecting header * - we haven't reached MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT yet * - its chain tip has at least as much work as ours * * CHAIN_SYNC_TIMEOUT: if a peer's best known block has less work than our tip, * set a timeout CHAIN_SYNC_TIMEOUT in the future: * - If at timeout their best known block now has more work than our tip * when the timeout was set, then either reset the timeout or clear it * (after comparing against our current tip's work) * - If at timeout their best known block still has less work than our * tip did when the timeout was set, then send a getheaders message, * and set a shorter timeout, HEADERS_RESPONSE_TIME seconds in future. * If their best known block is still behind when that new timeout is * reached, disconnect. * * EXTRA_PEER_CHECK_INTERVAL: after each interval, if we have too many outbound peers, * drop the outbound one that least recently announced us a new block. */ struct ChainSyncTimeoutState { //! A timeout used for checking whether our peer has sufficiently synced std::chrono::seconds m_timeout{0s}; //! A header with the work we require on our peer's chain const CBlockIndex* m_work_header{nullptr}; //! After timeout is reached, set to true after sending getheaders bool m_sent_getheaders{false}; //! Whether this peer is protected from disconnection due to a bad/slow chain bool m_protect{false}; }; ChainSyncTimeoutState m_chain_sync; //! Time of last new block announcement int64_t m_last_block_announcement{0}; //! Whether this peer is an inbound connection const bool m_is_inbound; CNodeState(bool is_inbound) : m_is_inbound(is_inbound) {} }; class PeerManagerImpl final : public PeerManager { public: PeerManagerImpl(CConnman& connman, AddrMan& addrman, BanMan* banman, ChainstateManager& chainman, CTxMemPool& pool, Options opts); /** Overridden from CValidationInterface. */ void BlockConnected(ChainstateRole role, const std::shared_ptr& pblock, const CBlockIndex* pindexConnected) override EXCLUSIVE_LOCKS_REQUIRED(!m_recent_confirmed_transactions_mutex); void BlockDisconnected(const std::shared_ptr &block, const CBlockIndex* pindex) override EXCLUSIVE_LOCKS_REQUIRED(!m_recent_confirmed_transactions_mutex); void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void BlockChecked(const CBlock& block, const BlockValidationState& state) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr& pblock) override EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex); /** Implement NetEventsInterface */ void InitializeNode(CNode& node, ServiceFlags our_services) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void FinalizeNode(const CNode& node) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_headers_presync_mutex); bool HasAllDesirableServiceFlags(ServiceFlags services) const override; bool ProcessMessages(CNode* pfrom, std::atomic& interrupt) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_recent_confirmed_transactions_mutex, !m_most_recent_block_mutex, !m_headers_presync_mutex, g_msgproc_mutex); bool SendMessages(CNode* pto) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_recent_confirmed_transactions_mutex, !m_most_recent_block_mutex, g_msgproc_mutex); /** Implement PeerManager */ void StartScheduledTasks(CScheduler& scheduler) override; void CheckForStaleTipAndEvictPeers() override; std::optional FetchBlock(NodeId peer_id, const CBlockIndex& block_index) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); PeerManagerInfo GetInfo() const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void SendPings() override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void RelayTransaction(const uint256& txid, const uint256& wtxid) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); void SetBestBlock(int height, std::chrono::seconds time) override { m_best_height = height; m_best_block_time = time; }; void UnitTestMisbehaving(NodeId peer_id, int howmuch) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex) { Misbehaving(*Assert(GetPeerRef(peer_id)), howmuch, ""); }; void ProcessMessage(CNode& pfrom, const std::string& msg_type, DataStream& vRecv, const std::chrono::microseconds time_received, const std::atomic& interruptMsgProc) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_recent_confirmed_transactions_mutex, !m_most_recent_block_mutex, !m_headers_presync_mutex, g_msgproc_mutex); void UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds) override; ServiceFlags GetDesirableServiceFlags(ServiceFlags services) const override; private: /** Consider evicting an outbound peer based on the amount of time they've been behind our tip */ void ConsiderEviction(CNode& pto, Peer& peer, std::chrono::seconds time_in_seconds) EXCLUSIVE_LOCKS_REQUIRED(cs_main, g_msgproc_mutex); /** If we have extra outbound peers, try to disconnect the one with the oldest block announcement */ void EvictExtraOutboundPeers(std::chrono::seconds now) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Retrieve unbroadcast transactions from the mempool and reattempt sending to peers */ void ReattemptInitialBroadcast(CScheduler& scheduler) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); /** Get a shared pointer to the Peer object. * May return an empty shared_ptr if the Peer object can't be found. */ PeerRef GetPeerRef(NodeId id) const EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); /** Get a shared pointer to the Peer object and remove it from m_peer_map. * May return an empty shared_ptr if the Peer object can't be found. */ PeerRef RemovePeer(NodeId id) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); /** * Increment peer's misbehavior score. If the new value >= DISCOURAGEMENT_THRESHOLD, mark the node * to be discouraged, meaning the peer might be disconnected and added to the discouragement filter. */ void Misbehaving(Peer& peer, int howmuch, const std::string& message); /** * Potentially mark a node discouraged based on the contents of a BlockValidationState 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) */ bool MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& state, bool via_compact_block, const std::string& message = "") EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); /** * Potentially disconnect and discourage a node based on the contents of a TxValidationState object * * @return Returns true if the peer was punished (probably disconnected) */ bool MaybePunishNodeForTx(NodeId nodeid, const TxValidationState& state) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex); /** Maybe disconnect a peer and discourage future connections from its address. * * @param[in] pnode The node to check. * @param[in] peer The peer object to check. * @return True if the peer was marked for disconnection in this function */ bool MaybeDiscourageAndDisconnect(CNode& pnode, Peer& peer); /** Handle a transaction whose result was not MempoolAcceptResult::ResultType::VALID. * @param[in] maybe_add_extra_compact_tx Whether this tx should be added to vExtraTxnForCompact. * Set to false if the tx has already been rejected before, * e.g. is an orphan, to avoid adding duplicate entries. * Updates m_txrequest, m_recent_rejects, m_recent_rejects_reconsiderable, m_orphanage, and vExtraTxnForCompact. */ void ProcessInvalidTx(NodeId nodeid, const CTransactionRef& tx, const TxValidationState& result, bool maybe_add_extra_compact_tx) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, cs_main); /** Handle a transaction whose result was MempoolAcceptResult::ResultType::VALID. * Updates m_txrequest, m_orphanage, and vExtraTxnForCompact. Also queues the tx for relay. */ void ProcessValidTx(NodeId nodeid, const CTransactionRef& tx, const std::list& replaced_transactions) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, cs_main); /** Handle the results of package validation: calls ProcessValidTx and ProcessInvalidTx for * individual transactions, and caches rejection for the package as a group. * @param[in] senders Must contain the nodeids of the peers that provided each transaction * in package, in the same order. * */ void ProcessPackageResult(const Package& package, const PackageMempoolAcceptResult& package_result, const std::vector& senders) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, cs_main); /** A package to validate */ struct PackageToValidate { const Package m_txns; const std::vector m_senders; /** Construct a 1-parent-1-child package. */ explicit PackageToValidate(const CTransactionRef& parent, const CTransactionRef& child, NodeId parent_sender, NodeId child_sender) : m_txns{parent, child}, m_senders {parent_sender, child_sender} {} std::string ToString() const { Assume(m_txns.size() == 2); return strprintf("parent %s (wtxid=%s, sender=%d) + child %s (wtxid=%s, sender=%d)", m_txns.front()->GetHash().ToString(), m_txns.front()->GetWitnessHash().ToString(), m_senders.front(), m_txns.back()->GetHash().ToString(), m_txns.back()->GetWitnessHash().ToString(), m_senders.back()); } }; /** Look for a child of this transaction in the orphanage to form a 1-parent-1-child package, * skipping any combinations that have already been tried. Return the resulting package along with * the senders of its respective transactions, or std::nullopt if no package is found. */ std::optional Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, cs_main); /** * Reconsider orphan transactions after a parent has been accepted to the mempool. * * @peer[in] peer The peer whose orphan transactions we will reconsider. Generally only * one orphan will be reconsidered on each call of this function. If an * accepted orphan has orphaned children, those will need to be * reconsidered, creating more work, possibly for other peers. * @return True if meaningful work was done (an orphan was accepted/rejected). * If no meaningful work was done, then the work set for this peer * will be empty. */ bool ProcessOrphanTx(Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex); /** Process a single headers message from a peer. * * @param[in] pfrom CNode of the peer * @param[in] peer The peer sending us the headers * @param[in] headers The headers received. Note that this may be modified within ProcessHeadersMessage. * @param[in] via_compact_block Whether this header came in via compact block handling. */ void ProcessHeadersMessage(CNode& pfrom, Peer& peer, std::vector&& headers, bool via_compact_block) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_headers_presync_mutex, g_msgproc_mutex); /** Various helpers for headers processing, invoked by ProcessHeadersMessage() */ /** Return true if headers are continuous and have valid proof-of-work (DoS points assigned on failure) */ bool CheckHeadersPoW(const std::vector& headers, const Consensus::Params& consensusParams, Peer& peer); /** Calculate an anti-DoS work threshold for headers chains */ arith_uint256 GetAntiDoSWorkThreshold(); /** Deal with state tracking and headers sync for peers that send the * occasional non-connecting header (this can happen due to BIP 130 headers * announcements for blocks interacting with the 2hr (MAX_FUTURE_BLOCK_TIME) rule). */ void HandleFewUnconnectingHeaders(CNode& pfrom, Peer& peer, const std::vector& headers) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); /** Return true if the headers connect to each other, false otherwise */ bool CheckHeadersAreContinuous(const std::vector& headers) const; /** Try to continue a low-work headers sync that has already begun. * Assumes the caller has already verified the headers connect, and has * checked that each header satisfies the proof-of-work target included in * the header. * @param[in] peer The peer we're syncing with. * @param[in] pfrom CNode of the peer * @param[in,out] headers The headers to be processed. * @return True if the passed in headers were successfully processed * as the continuation of a low-work headers sync in progress; * false otherwise. * If false, the passed in headers will be returned back to * the caller. * If true, the returned headers may be empty, indicating * there is no more work for the caller to do; or the headers * may be populated with entries that have passed anti-DoS * checks (and therefore may be validated for block index * acceptance by the caller). */ bool IsContinuationOfLowWorkHeadersSync(Peer& peer, CNode& pfrom, std::vector& headers) EXCLUSIVE_LOCKS_REQUIRED(peer.m_headers_sync_mutex, !m_headers_presync_mutex, g_msgproc_mutex); /** Check work on a headers chain to be processed, and if insufficient, * initiate our anti-DoS headers sync mechanism. * * @param[in] peer The peer whose headers we're processing. * @param[in] pfrom CNode of the peer * @param[in] chain_start_header Where these headers connect in our index. * @param[in,out] headers The headers to be processed. * * @return True if chain was low work (headers will be empty after * calling); false otherwise. */ bool TryLowWorkHeadersSync(Peer& peer, CNode& pfrom, const CBlockIndex* chain_start_header, std::vector& headers) EXCLUSIVE_LOCKS_REQUIRED(!peer.m_headers_sync_mutex, !m_peer_mutex, !m_headers_presync_mutex, g_msgproc_mutex); /** Return true if the given header is an ancestor of * m_chainman.m_best_header or our current tip */ bool IsAncestorOfBestHeaderOrTip(const CBlockIndex* header) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Request further headers from this peer with a given locator. * We don't issue a getheaders message if we have a recent one outstanding. * This returns true if a getheaders is actually sent, and false otherwise. */ bool MaybeSendGetHeaders(CNode& pfrom, const CBlockLocator& locator, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); /** Potentially fetch blocks from this peer upon receipt of a new headers tip */ void HeadersDirectFetchBlocks(CNode& pfrom, const Peer& peer, const CBlockIndex& last_header); /** Update peer state based on received headers message */ void UpdatePeerStateForReceivedHeaders(CNode& pfrom, Peer& peer, const CBlockIndex& last_header, bool received_new_header, bool may_have_more_headers) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); void SendBlockTransactions(CNode& pfrom, Peer& peer, const CBlock& block, const BlockTransactionsRequest& req); /** Register with TxRequestTracker that an INV has been received from a * peer. The announcement parameters are decided in PeerManager and then * passed to TxRequestTracker. */ void AddTxAnnouncement(const CNode& node, const GenTxid& gtxid, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(::cs_main); /** Send a message to a peer */ void PushMessage(CNode& node, CSerializedNetMsg&& msg) const { m_connman.PushMessage(&node, std::move(msg)); } template void MakeAndPushMessage(CNode& node, std::string msg_type, Args&&... args) const { m_connman.PushMessage(&node, NetMsg::Make(std::move(msg_type), std::forward(args)...)); } /** Send a version message to a peer */ void PushNodeVersion(CNode& pnode, const Peer& peer); /** Send a ping message every PING_INTERVAL or if requested via RPC. May * mark the peer to be disconnected if a ping has timed out. * We use mockable time for ping timeouts, so setmocktime may cause pings * to time out. */ void MaybeSendPing(CNode& node_to, Peer& peer, std::chrono::microseconds now); /** Send `addr` messages on a regular schedule. */ void MaybeSendAddr(CNode& node, Peer& peer, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); /** Send a single `sendheaders` message, after we have completed headers sync with a peer. */ void MaybeSendSendHeaders(CNode& node, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); /** Relay (gossip) an address to a few randomly chosen nodes. * * @param[in] originator The id of the peer that sent us the address. We don't want to relay it back. * @param[in] addr Address to relay. * @param[in] fReachable Whether the address' network is reachable. We relay unreachable * addresses less. */ void RelayAddress(NodeId originator, const CAddress& addr, bool fReachable) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex); /** Send `feefilter` message. */ void MaybeSendFeefilter(CNode& node, Peer& peer, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); FastRandomContext m_rng GUARDED_BY(NetEventsInterface::g_msgproc_mutex); FeeFilterRounder m_fee_filter_rounder GUARDED_BY(NetEventsInterface::g_msgproc_mutex); const CChainParams& m_chainparams; CConnman& m_connman; AddrMan& m_addrman; /** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */ BanMan* const m_banman; ChainstateManager& m_chainman; CTxMemPool& m_mempool; TxRequestTracker m_txrequest GUARDED_BY(::cs_main); std::unique_ptr m_txreconciliation; /** The height of the best chain */ std::atomic m_best_height{-1}; /** The time of the best chain tip block */ std::atomic m_best_block_time{0s}; /** Next time to check for stale tip */ std::chrono::seconds m_stale_tip_check_time GUARDED_BY(cs_main){0s}; TimeOffsets m_outbound_time_offsets; const Options m_opts; bool RejectIncomingTxs(const CNode& peer) const; /** Whether we've completed initial sync yet, for determining when to turn * on extra block-relay-only peers. */ bool m_initial_sync_finished GUARDED_BY(cs_main){false}; /** Protects m_peer_map. This mutex must not be locked while holding a lock * on any of the mutexes inside a Peer object. */ mutable Mutex m_peer_mutex; /** * Map of all Peer objects, keyed by peer id. This map is protected * by the m_peer_mutex. Once a shared pointer reference is * taken, the lock may be released. Individual fields are protected by * their own locks. */ std::map m_peer_map GUARDED_BY(m_peer_mutex); /** Map maintaining per-node state. */ std::map m_node_states GUARDED_BY(cs_main); /** Get a pointer to a const CNodeState, used when not mutating the CNodeState object. */ const CNodeState* State(NodeId pnode) const EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Get a pointer to a mutable CNodeState. */ CNodeState* State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main); uint32_t GetFetchFlags(const Peer& peer) const; std::atomic m_next_inv_to_inbounds{0us}; /** Number of nodes with fSyncStarted. */ int nSyncStarted GUARDED_BY(cs_main) = 0; /** Hash of the last block we received via INV */ uint256 m_last_block_inv_triggering_headers_sync GUARDED_BY(g_msgproc_mutex){}; /** * Sources of received blocks, saved to be able punish them when processing * happens afterwards. * Set mapBlockSource[hash].second to false if the node should not be * punished if the block is invalid. */ std::map> mapBlockSource GUARDED_BY(cs_main); /** Number of peers with wtxid relay. */ std::atomic m_wtxid_relay_peers{0}; /** Number of outbound peers with m_chain_sync.m_protect. */ int m_outbound_peers_with_protect_from_disconnect GUARDED_BY(cs_main) = 0; /** Number of preferable block download peers. */ int m_num_preferred_download_peers GUARDED_BY(cs_main){0}; /** Stalling timeout for blocks in IBD */ std::atomic m_block_stalling_timeout{BLOCK_STALLING_TIMEOUT_DEFAULT}; /** Check whether we already have this gtxid in: * - mempool * - orphanage * - m_recent_rejects * - m_recent_rejects_reconsiderable (if include_reconsiderable = true) * - m_recent_confirmed_transactions * Also responsible for resetting m_recent_rejects and m_recent_rejects_reconsiderable if the * chain tip has changed. * */ bool AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable) EXCLUSIVE_LOCKS_REQUIRED(cs_main, !m_recent_confirmed_transactions_mutex); /** * Filter for transactions that were recently rejected by the mempool. * These are not rerequested until the chain tip changes, at which point * the entire filter is reset. * * Without this filter we'd be re-requesting txs from each of our peers, * increasing bandwidth consumption considerably. For instance, with 100 * peers, half of which relay a tx we don't accept, that might be a 50x * bandwidth increase. A flooding attacker attempting to roll-over the * filter using minimum-sized, 60byte, transactions might manage to send * 1000/sec if we have fast peers, so we pick 120,000 to give our peers a * two minute window to send invs to us. * * Decreasing the false positive rate is fairly cheap, so we pick one in a * million to make it highly unlikely for users to have issues with this * filter. * * We typically only add wtxids to this filter. For non-segwit * transactions, the txid == wtxid, so this only prevents us from * re-downloading non-segwit transactions when communicating with * non-wtxidrelay peers -- which is important for avoiding malleation * attacks that could otherwise interfere with transaction relay from * non-wtxidrelay peers. For communicating with wtxidrelay peers, having * the reject filter store wtxids is exactly what we want to avoid * redownload of a rejected transaction. * * In cases where we can tell that a segwit transaction will fail * validation no matter the witness, we may add the txid of such * transaction to the filter as well. This can be helpful when * communicating with txid-relay peers or if we were to otherwise fetch a * transaction via txid (eg in our orphan handling). * * Memory used: 1.3 MB */ CRollingBloomFilter m_recent_rejects GUARDED_BY(::cs_main){120'000, 0.000'001}; /** Block hash of chain tip the last time we reset m_recent_rejects and * m_recent_rejects_reconsiderable. */ uint256 hashRecentRejectsChainTip GUARDED_BY(cs_main); /** * Filter for: * (1) wtxids of transactions that were recently rejected by the mempool but are * eligible for reconsideration if submitted with other transactions. * (2) packages (see GetPackageHash) we have already rejected before and should not retry. * * Similar to m_recent_rejects, this filter is used to save bandwidth when e.g. all of our peers * have larger mempools and thus lower minimum feerates than us. * * When a transaction's error is TxValidationResult::TX_RECONSIDERABLE (in a package or by * itself), add its wtxid to this filter. When a package fails for any reason, add the combined * hash to this filter. * * Upon receiving an announcement for a transaction, if it exists in this filter, do not * download the txdata. When considering packages, if it exists in this filter, drop it. * * Reset this filter when the chain tip changes. * * Parameters are picked to be the same as m_recent_rejects, with the same rationale. */ CRollingBloomFilter m_recent_rejects_reconsiderable GUARDED_BY(::cs_main){120'000, 0.000'001}; /* * Filter for transactions that have been recently confirmed. * We use this to avoid requesting transactions that have already been * confirnmed. * * Blocks don't typically have more than 4000 transactions, so this should * be at least six blocks (~1 hr) worth of transactions that we can store, * inserting both a txid and wtxid for every observed transaction. * If the number of transactions appearing in a block goes up, or if we are * seeing getdata requests more than an hour after initial announcement, we * can increase this number. * The false positive rate of 1/1M should come out to less than 1 * transaction per day that would be inadvertently ignored (which is the * same probability that we have in the reject filter). */ Mutex m_recent_confirmed_transactions_mutex; CRollingBloomFilter m_recent_confirmed_transactions GUARDED_BY(m_recent_confirmed_transactions_mutex){48'000, 0.000'001}; /** * For sending `inv`s to inbound peers, we use a single (exponentially * distributed) timer for all peers. If we used a separate timer for each * peer, a spy node could make multiple inbound connections to us to * accurately determine when we received the transaction (and potentially * determine the transaction's origin). */ std::chrono::microseconds NextInvToInbounds(std::chrono::microseconds now, std::chrono::seconds average_interval); // All of the following cache a recent block, and are protected by m_most_recent_block_mutex Mutex m_most_recent_block_mutex; std::shared_ptr m_most_recent_block GUARDED_BY(m_most_recent_block_mutex); std::shared_ptr m_most_recent_compact_block GUARDED_BY(m_most_recent_block_mutex); uint256 m_most_recent_block_hash GUARDED_BY(m_most_recent_block_mutex); std::unique_ptr> m_most_recent_block_txs GUARDED_BY(m_most_recent_block_mutex); // Data about the low-work headers synchronization, aggregated from all peers' HeadersSyncStates. /** Mutex guarding the other m_headers_presync_* variables. */ Mutex m_headers_presync_mutex; /** A type to represent statistics about a peer's low-work headers sync. * * - The first field is the total verified amount of work in that synchronization. * - The second is: * - nullopt: the sync is in REDOWNLOAD phase (phase 2). * - {height, timestamp}: the sync has the specified tip height and block timestamp (phase 1). */ using HeadersPresyncStats = std::pair>>; /** Statistics for all peers in low-work headers sync. */ std::map m_headers_presync_stats GUARDED_BY(m_headers_presync_mutex) {}; /** The peer with the most-work entry in m_headers_presync_stats. */ NodeId m_headers_presync_bestpeer GUARDED_BY(m_headers_presync_mutex) {-1}; /** The m_headers_presync_stats improved, and needs signalling. */ std::atomic_bool m_headers_presync_should_signal{false}; /** Height of the highest block announced using BIP 152 high-bandwidth mode. */ int m_highest_fast_announce GUARDED_BY(::cs_main){0}; /** Have we requested this block from a peer */ bool IsBlockRequested(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Have we requested this block from an outbound peer */ bool IsBlockRequestedFromOutbound(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Remove this block from our tracked requested blocks. Called if: * - the block has been received from a peer * - the request for the block has timed out * If "from_peer" is specified, then only remove the block if it is in * flight from that peer (to avoid one peer's network traffic from * affecting another's state). */ void RemoveBlockRequest(const uint256& hash, std::optional from_peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /* Mark a block as in flight * 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 */ bool BlockRequested(NodeId nodeid, const CBlockIndex& block, std::list::iterator** pit = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_main); bool TipMayBeStale() EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Update pindexLastCommonBlock and add not-in-flight missing successors to vBlocks, until it has * at most count entries. */ void FindNextBlocksToDownload(const Peer& peer, unsigned int count, std::vector& vBlocks, NodeId& nodeStaller) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Request blocks for the background chainstate, if one is in use. */ void TryDownloadingHistoricalBlocks(const Peer& peer, unsigned int count, std::vector& vBlocks, const CBlockIndex* from_tip, const CBlockIndex* target_block) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** * \brief Find next blocks to download from a peer after a starting block. * * \param vBlocks Vector of blocks to download which will be appended to. * \param peer Peer which blocks will be downloaded from. * \param state Pointer to the state of the peer. * \param pindexWalk Pointer to the starting block to add to vBlocks. * \param count Maximum number of blocks to allow in vBlocks. No more * blocks will be added if it reaches this size. * \param nWindowEnd Maximum height of blocks to allow in vBlocks. No * blocks will be added above this height. * \param activeChain Optional pointer to a chain to compare against. If * provided, any next blocks which are already contained * in this chain will not be appended to vBlocks, but * instead will be used to update the * state->pindexLastCommonBlock pointer. * \param nodeStaller Optional pointer to a NodeId variable that will receive * the ID of another peer that might be causing this peer * to stall. This is set to the ID of the peer which * first requested the first in-flight block in the * download window. It is only set if vBlocks is empty at * the end of this function call and if increasing * nWindowEnd by 1 would cause it to be non-empty (which * indicates the download might be stalled because every * block in the window is in flight and no other peer is * trying to download the next block). */ void FindNextBlocks(std::vector& vBlocks, const Peer& peer, CNodeState *state, const CBlockIndex *pindexWalk, unsigned int count, int nWindowEnd, const CChain* activeChain=nullptr, NodeId* nodeStaller=nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /* Multimap used to preserve insertion order */ typedef std::multimap::iterator>> BlockDownloadMap; BlockDownloadMap mapBlocksInFlight GUARDED_BY(cs_main); /** When our tip was last updated. */ std::atomic m_last_tip_update{0s}; /** Determine whether or not a peer can request a transaction, and return it (or nullptr if not found or not allowed). */ CTransactionRef FindTxForGetData(const Peer::TxRelay& tx_relay, const GenTxid& gtxid) EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex, NetEventsInterface::g_msgproc_mutex); void ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic& interruptMsgProc) EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex, peer.m_getdata_requests_mutex, NetEventsInterface::g_msgproc_mutex) LOCKS_EXCLUDED(::cs_main); /** Process a new block. Perform any post-processing housekeeping */ void ProcessBlock(CNode& node, const std::shared_ptr& block, bool force_processing, bool min_pow_checked); /** Process compact block txns */ void ProcessCompactBlockTxns(CNode& pfrom, Peer& peer, const BlockTransactions& block_transactions) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex, !m_most_recent_block_mutex); /** * 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. */ void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Stack of nodes which we have set to announce using compact blocks */ std::list lNodesAnnouncingHeaderAndIDs GUARDED_BY(cs_main); /** Number of peers from which we're downloading blocks. */ int m_peers_downloading_from GUARDED_BY(cs_main) = 0; /** Storage for orphan information */ TxOrphanage m_orphanage; void AddToCompactExtraTransactions(const CTransactionRef& tx) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); /** Orphan/conflicted/etc transactions that are kept for compact block reconstruction. * The last -blockreconstructionextratxn/DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN of * these are kept in a ring buffer */ std::vector vExtraTxnForCompact GUARDED_BY(g_msgproc_mutex); /** Offset into vExtraTxnForCompact to insert the next tx */ size_t vExtraTxnForCompactIt GUARDED_BY(g_msgproc_mutex) = 0; /** Check whether the last unknown block a peer advertised is not yet known. */ void ProcessBlockAvailability(NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** Update tracking information about which blocks a peer is assumed to have. */ void UpdateBlockAvailability(NodeId nodeid, const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main); bool CanDirectFetch() EXCLUSIVE_LOCKS_REQUIRED(cs_main); /** * Estimates the distance, in blocks, between the best-known block and the network chain tip. * Utilizes the best-block time and the chainparams blocks spacing to approximate it. */ int64_t ApproximateBestBlockDepth() const; /** * 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. */ bool BlockRequestAllowed(const CBlockIndex* pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main); bool AlreadyHaveBlock(const uint256& block_hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main); void ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv& inv) EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex); /** * Validation logic for compact filters request handling. * * May disconnect from the peer in the case of a bad request. * * @param[in] node The node that we received the request from * @param[in] peer The peer that we received the request from * @param[in] filter_type The filter type the request is for. Must be basic filters. * @param[in] start_height The start height for the request * @param[in] stop_hash The stop_hash for the request * @param[in] max_height_diff The maximum number of items permitted to request, as specified in BIP 157 * @param[out] stop_index The CBlockIndex for the stop_hash block, if the request can be serviced. * @param[out] filter_index The filter index, if the request can be serviced. * @return True if the request can be serviced. */ bool PrepareBlockFilterRequest(CNode& node, Peer& peer, BlockFilterType filter_type, uint32_t start_height, const uint256& stop_hash, uint32_t max_height_diff, const CBlockIndex*& stop_index, BlockFilterIndex*& filter_index); /** * Handle a cfilters request. * * May disconnect from the peer in the case of a bad request. * * @param[in] node The node that we received the request from * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received */ void ProcessGetCFilters(CNode& node, Peer& peer, DataStream& vRecv); /** * Handle a cfheaders request. * * May disconnect from the peer in the case of a bad request. * * @param[in] node The node that we received the request from * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received */ void ProcessGetCFHeaders(CNode& node, Peer& peer, DataStream& vRecv); /** * Handle a getcfcheckpt request. * * May disconnect from the peer in the case of a bad request. * * @param[in] node The node that we received the request from * @param[in] peer The peer that we received the request from * @param[in] vRecv The raw message received */ void ProcessGetCFCheckPt(CNode& node, Peer& peer, DataStream& vRecv); /** Checks if address relay is permitted with peer. If needed, initializes * the m_addr_known bloom filter and sets m_addr_relay_enabled to true. * * @return True if address relay is enabled with peer * False if address relay is disallowed */ bool SetupAddressRelay(const CNode& node, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); void AddAddressKnown(Peer& peer, const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); void PushAddress(Peer& peer, const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex); }; const CNodeState* PeerManagerImpl::State(NodeId pnode) const EXCLUSIVE_LOCKS_REQUIRED(cs_main) { std::map::const_iterator it = m_node_states.find(pnode); if (it == m_node_states.end()) return nullptr; return &it->second; } CNodeState* PeerManagerImpl::State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return const_cast(std::as_const(*this).State(pnode)); } /** * Whether the peer supports the address. For example, a peer that does not * implement BIP155 cannot receive Tor v3 addresses because it requires * ADDRv2 (BIP155) encoding. */ static bool IsAddrCompatible(const Peer& peer, const CAddress& addr) { return peer.m_wants_addrv2 || addr.IsAddrV1Compatible(); } void PeerManagerImpl::AddAddressKnown(Peer& peer, const CAddress& addr) { assert(peer.m_addr_known); peer.m_addr_known->insert(addr.GetKey()); } void PeerManagerImpl::PushAddress(Peer& peer, const CAddress& addr) { // Known checking here is only to save space from duplicates. // Before sending, we'll filter it again for known addresses that were // added after addresses were pushed. assert(peer.m_addr_known); if (addr.IsValid() && !peer.m_addr_known->contains(addr.GetKey()) && IsAddrCompatible(peer, addr)) { if (peer.m_addrs_to_send.size() >= MAX_ADDR_TO_SEND) { peer.m_addrs_to_send[m_rng.randrange(peer.m_addrs_to_send.size())] = addr; } else { peer.m_addrs_to_send.push_back(addr); } } } static void AddKnownTx(Peer& peer, const uint256& hash) { auto tx_relay = peer.GetTxRelay(); if (!tx_relay) return; LOCK(tx_relay->m_tx_inventory_mutex); tx_relay->m_tx_inventory_known_filter.insert(hash); } /** Whether this peer can serve us blocks. */ static bool CanServeBlocks(const Peer& peer) { return peer.m_their_services & (NODE_NETWORK|NODE_NETWORK_LIMITED); } /** Whether this peer can only serve limited recent blocks (e.g. because * it prunes old blocks) */ static bool IsLimitedPeer(const Peer& peer) { return (!(peer.m_their_services & NODE_NETWORK) && (peer.m_their_services & NODE_NETWORK_LIMITED)); } /** Whether this peer can serve us witness data */ static bool CanServeWitnesses(const Peer& peer) { return peer.m_their_services & NODE_WITNESS; } std::chrono::microseconds PeerManagerImpl::NextInvToInbounds(std::chrono::microseconds now, std::chrono::seconds average_interval) { if (m_next_inv_to_inbounds.load() < now) { // If this function were called from multiple threads simultaneously // it would possible that both update the next send variable, and return a different result to their caller. // This is not possible in practice as only the net processing thread invokes this function. m_next_inv_to_inbounds = GetExponentialRand(now, average_interval); } return m_next_inv_to_inbounds; } bool PeerManagerImpl::IsBlockRequested(const uint256& hash) { return mapBlocksInFlight.count(hash); } bool PeerManagerImpl::IsBlockRequestedFromOutbound(const uint256& hash) { for (auto range = mapBlocksInFlight.equal_range(hash); range.first != range.second; range.first++) { auto [nodeid, block_it] = range.first->second; CNodeState& nodestate = *Assert(State(nodeid)); if (!nodestate.m_is_inbound) return true; } return false; } void PeerManagerImpl::RemoveBlockRequest(const uint256& hash, std::optional from_peer) { auto range = mapBlocksInFlight.equal_range(hash); if (range.first == range.second) { // Block was not requested from any peer return; } // We should not have requested too many of this block Assume(mapBlocksInFlight.count(hash) <= MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK); while (range.first != range.second) { auto [node_id, list_it] = range.first->second; if (from_peer && *from_peer != node_id) { range.first++; continue; } CNodeState& state = *Assert(State(node_id)); if (state.vBlocksInFlight.begin() == list_it) { // First block on the queue was received, update the start download time for the next one state.m_downloading_since = std::max(state.m_downloading_since, GetTime()); } state.vBlocksInFlight.erase(list_it); if (state.vBlocksInFlight.empty()) { // Last validated block on the queue for this peer was received. m_peers_downloading_from--; } state.m_stalling_since = 0us; range.first = mapBlocksInFlight.erase(range.first); } } bool PeerManagerImpl::BlockRequested(NodeId nodeid, const CBlockIndex& block, std::list::iterator** pit) { const uint256& hash{block.GetBlockHash()}; CNodeState *state = State(nodeid); assert(state != nullptr); Assume(mapBlocksInFlight.count(hash) <= MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK); // Short-circuit most stuff in case it is from the same node for (auto range = mapBlocksInFlight.equal_range(hash); range.first != range.second; range.first++) { if (range.first->second.first == nodeid) { if (pit) { *pit = &range.first->second.second; } return false; } } // Make sure it's not being fetched already from same peer. RemoveBlockRequest(hash, nodeid); std::list::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(), {&block, std::unique_ptr(pit ? new PartiallyDownloadedBlock(&m_mempool) : nullptr)}); if (state->vBlocksInFlight.size() == 1) { // We're starting a block download (batch) from this peer. state->m_downloading_since = GetTime(); m_peers_downloading_from++; } auto itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it))); if (pit) { *pit = &itInFlight->second.second; } return true; } void PeerManagerImpl::MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid) { AssertLockHeld(cs_main); // When in -blocksonly mode, never request high-bandwidth mode from peers. Our // mempool will not contain the transactions necessary to reconstruct the // compact block. if (m_opts.ignore_incoming_txs) return; CNodeState* nodestate = State(nodeid); if (!nodestate || !nodestate->m_provides_cmpctblocks) { // Don't request compact blocks if the peer has not signalled support return; } int num_outbound_hb_peers = 0; for (std::list::iterator it = lNodesAnnouncingHeaderAndIDs.begin(); it != lNodesAnnouncingHeaderAndIDs.end(); it++) { if (*it == nodeid) { lNodesAnnouncingHeaderAndIDs.erase(it); lNodesAnnouncingHeaderAndIDs.push_back(nodeid); return; } CNodeState *state = State(*it); if (state != nullptr && !state->m_is_inbound) ++num_outbound_hb_peers; } if (nodestate->m_is_inbound) { // If we're adding an inbound HB peer, make sure we're not removing // our last outbound HB peer in the process. if (lNodesAnnouncingHeaderAndIDs.size() >= 3 && num_outbound_hb_peers == 1) { CNodeState *remove_node = State(lNodesAnnouncingHeaderAndIDs.front()); if (remove_node != nullptr && !remove_node->m_is_inbound) { // Put the HB outbound peer in the second slot, so that it // doesn't get removed. std::swap(lNodesAnnouncingHeaderAndIDs.front(), *std::next(lNodesAnnouncingHeaderAndIDs.begin())); } } } m_connman.ForNode(nodeid, [this](CNode* pfrom) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); if (lNodesAnnouncingHeaderAndIDs.size() >= 3) { // As per BIP152, we only get 3 of our peers to announce // blocks using compact encodings. m_connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(), [this](CNode* pnodeStop){ MakeAndPushMessage(*pnodeStop, NetMsgType::SENDCMPCT, /*high_bandwidth=*/false, /*version=*/CMPCTBLOCKS_VERSION); // save BIP152 bandwidth state: we select peer to be low-bandwidth pnodeStop->m_bip152_highbandwidth_to = false; return true; }); lNodesAnnouncingHeaderAndIDs.pop_front(); } MakeAndPushMessage(*pfrom, NetMsgType::SENDCMPCT, /*high_bandwidth=*/true, /*version=*/CMPCTBLOCKS_VERSION); // save BIP152 bandwidth state: we select peer to be high-bandwidth pfrom->m_bip152_highbandwidth_to = true; lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId()); return true; }); } bool PeerManagerImpl::TipMayBeStale() { AssertLockHeld(cs_main); const Consensus::Params& consensusParams = m_chainparams.GetConsensus(); if (m_last_tip_update.load() == 0s) { m_last_tip_update = GetTime(); } return m_last_tip_update.load() < GetTime() - std::chrono::seconds{consensusParams.nPowTargetSpacing * 3} && mapBlocksInFlight.empty(); } int64_t PeerManagerImpl::ApproximateBestBlockDepth() const { return (GetTime() - m_best_block_time.load()).count() / m_chainparams.GetConsensus().nPowTargetSpacing; } bool PeerManagerImpl::CanDirectFetch() { return m_chainman.ActiveChain().Tip()->Time() > NodeClock::now() - m_chainparams.GetConsensus().PowTargetSpacing() * 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; } void PeerManagerImpl::ProcessBlockAvailability(NodeId nodeid) { CNodeState *state = State(nodeid); assert(state != nullptr); if (!state->hashLastUnknownBlock.IsNull()) { const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(state->hashLastUnknownBlock); if (pindex && pindex->nChainWork > 0) { if (state->pindexBestKnownBlock == nullptr || pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) { state->pindexBestKnownBlock = pindex; } state->hashLastUnknownBlock.SetNull(); } } } void PeerManagerImpl::UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) { CNodeState *state = State(nodeid); assert(state != nullptr); ProcessBlockAvailability(nodeid); const CBlockIndex* pindex = m_chainman.m_blockman.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; } } // Logic for calculating which blocks to download from a given peer, given our current tip. void PeerManagerImpl::FindNextBlocksToDownload(const Peer& peer, unsigned int count, std::vector& vBlocks, NodeId& nodeStaller) { if (count == 0) return; vBlocks.reserve(vBlocks.size() + count); CNodeState *state = State(peer.m_id); assert(state != nullptr); // Make sure pindexBestKnownBlock is up to date, we'll need it. ProcessBlockAvailability(peer.m_id); if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->nChainWork < m_chainman.ActiveChain().Tip()->nChainWork || state->pindexBestKnownBlock->nChainWork < m_chainman.MinimumChainWork()) { // 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 = m_chainman.ActiveChain()[std::min(state->pindexBestKnownBlock->nHeight, m_chainman.ActiveChain().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; 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; FindNextBlocks(vBlocks, peer, state, pindexWalk, count, nWindowEnd, &m_chainman.ActiveChain(), &nodeStaller); } void PeerManagerImpl::TryDownloadingHistoricalBlocks(const Peer& peer, unsigned int count, std::vector& vBlocks, const CBlockIndex *from_tip, const CBlockIndex* target_block) { Assert(from_tip); Assert(target_block); if (vBlocks.size() >= count) { return; } vBlocks.reserve(count); CNodeState *state = Assert(State(peer.m_id)); if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->GetAncestor(target_block->nHeight) != target_block) { // This peer can't provide us the complete series of blocks leading up to the // assumeutxo snapshot base. // // Presumably this peer's chain has less work than our ActiveChain()'s tip, or else we // will eventually crash when we try to reorg to it. Let other logic // deal with whether we disconnect this peer. // // TODO at some point in the future, we might choose to request what blocks // this peer does have from the historical chain, despite it not having a // complete history beneath the snapshot base. return; } FindNextBlocks(vBlocks, peer, state, from_tip, count, std::min(from_tip->nHeight + BLOCK_DOWNLOAD_WINDOW, target_block->nHeight)); } void PeerManagerImpl::FindNextBlocks(std::vector& vBlocks, const Peer& peer, CNodeState *state, const CBlockIndex *pindexWalk, unsigned int count, int nWindowEnd, const CChain* activeChain, NodeId* nodeStaller) { std::vector vToFetch; int nMaxHeight = std::min(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1); bool is_limited_peer = IsLimitedPeer(peer); 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 (!CanServeWitnesses(peer) && DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) { // We wouldn't download this block or its descendants from this peer. return; } if (pindex->nStatus & BLOCK_HAVE_DATA || (activeChain && activeChain->Contains(pindex))) { if (activeChain && pindex->HaveNumChainTxs()) { state->pindexLastCommonBlock = pindex; } continue; } // Is block in-flight? if (IsBlockRequested(pindex->GetBlockHash())) { if (waitingfor == -1) { // This is the first already-in-flight block. waitingfor = mapBlocksInFlight.lower_bound(pindex->GetBlockHash())->second.first; } continue; } // 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 != peer.m_id) { // We aren't able to fetch anything, but we would be if the download window was one larger. if (nodeStaller) *nodeStaller = waitingfor; } return; } // Don't request blocks that go further than what limited peers can provide if (is_limited_peer && (state->pindexBestKnownBlock->nHeight - pindex->nHeight >= static_cast(NODE_NETWORK_LIMITED_MIN_BLOCKS) - 2 /* two blocks buffer for possible races */)) { continue; } vBlocks.push_back(pindex); if (vBlocks.size() == count) { return; } } } } } // namespace void PeerManagerImpl::PushNodeVersion(CNode& pnode, const Peer& peer) { uint64_t my_services{peer.m_our_services}; const int64_t nTime{count_seconds(GetTime())}; uint64_t nonce = pnode.GetLocalNonce(); const int nNodeStartingHeight{m_best_height}; NodeId nodeid = pnode.GetId(); CAddress addr = pnode.addr; CService addr_you = addr.IsRoutable() && !IsProxy(addr) && addr.IsAddrV1Compatible() ? addr : CService(); uint64_t your_services{addr.nServices}; const bool tx_relay{!RejectIncomingTxs(pnode)}; MakeAndPushMessage(pnode, NetMsgType::VERSION, PROTOCOL_VERSION, my_services, nTime, your_services, CNetAddr::V1(addr_you), // Together the pre-version-31402 serialization of CAddress "addrYou" (without nTime) my_services, CNetAddr::V1(CService{}), // Together the pre-version-31402 serialization of CAddress "addrMe" (without nTime) nonce, strSubVersion, nNodeStartingHeight, tx_relay); if (fLogIPs) { LogPrint(BCLog::NET, "send version message: version %d, blocks=%d, them=%s, txrelay=%d, peer=%d\n", PROTOCOL_VERSION, nNodeStartingHeight, addr_you.ToStringAddrPort(), tx_relay, nodeid); } else { LogPrint(BCLog::NET, "send version message: version %d, blocks=%d, txrelay=%d, peer=%d\n", PROTOCOL_VERSION, nNodeStartingHeight, tx_relay, nodeid); } } void PeerManagerImpl::AddTxAnnouncement(const CNode& node, const GenTxid& gtxid, std::chrono::microseconds current_time) { AssertLockHeld(::cs_main); // For m_txrequest NodeId nodeid = node.GetId(); if (!node.HasPermission(NetPermissionFlags::Relay) && m_txrequest.Count(nodeid) >= MAX_PEER_TX_ANNOUNCEMENTS) { // Too many queued announcements from this peer return; } const CNodeState* state = State(nodeid); // Decide the TxRequestTracker parameters for this announcement: // - "preferred": if fPreferredDownload is set (= outbound, or NetPermissionFlags::NoBan permission) // - "reqtime": current time plus delays for: // - NONPREF_PEER_TX_DELAY for announcements from non-preferred connections // - TXID_RELAY_DELAY for txid announcements while wtxid peers are available // - OVERLOADED_PEER_TX_DELAY for announcements from peers which have at least // MAX_PEER_TX_REQUEST_IN_FLIGHT requests in flight (and don't have NetPermissionFlags::Relay). auto delay{0us}; const bool preferred = state->fPreferredDownload; if (!preferred) delay += NONPREF_PEER_TX_DELAY; if (!gtxid.IsWtxid() && m_wtxid_relay_peers > 0) delay += TXID_RELAY_DELAY; const bool overloaded = !node.HasPermission(NetPermissionFlags::Relay) && m_txrequest.CountInFlight(nodeid) >= MAX_PEER_TX_REQUEST_IN_FLIGHT; if (overloaded) delay += OVERLOADED_PEER_TX_DELAY; m_txrequest.ReceivedInv(nodeid, gtxid, preferred, current_time + delay); } void PeerManagerImpl::UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds) { LOCK(cs_main); CNodeState *state = State(node); if (state) state->m_last_block_announcement = time_in_seconds; } void PeerManagerImpl::InitializeNode(CNode& node, ServiceFlags our_services) { NodeId nodeid = node.GetId(); { LOCK(cs_main); m_node_states.emplace_hint(m_node_states.end(), std::piecewise_construct, std::forward_as_tuple(nodeid), std::forward_as_tuple(node.IsInboundConn())); assert(m_txrequest.Count(nodeid) == 0); } if (NetPermissions::HasFlag(node.m_permission_flags, NetPermissionFlags::BloomFilter)) { our_services = static_cast(our_services | NODE_BLOOM); } PeerRef peer = std::make_shared(nodeid, our_services); { LOCK(m_peer_mutex); m_peer_map.emplace_hint(m_peer_map.end(), nodeid, peer); } if (!node.IsInboundConn()) { PushNodeVersion(node, *peer); } } void PeerManagerImpl::ReattemptInitialBroadcast(CScheduler& scheduler) { std::set unbroadcast_txids = m_mempool.GetUnbroadcastTxs(); for (const auto& txid : unbroadcast_txids) { CTransactionRef tx = m_mempool.get(txid); if (tx != nullptr) { RelayTransaction(txid, tx->GetWitnessHash()); } else { m_mempool.RemoveUnbroadcastTx(txid, true); } } // Schedule next run for 10-15 minutes in the future. // We add randomness on every cycle to avoid the possibility of P2P fingerprinting. const std::chrono::milliseconds delta = 10min + GetRandMillis(5min); scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta); } void PeerManagerImpl::FinalizeNode(const CNode& node) { NodeId nodeid = node.GetId(); int misbehavior{0}; { LOCK(cs_main); { // We remove the PeerRef from g_peer_map here, but we don't always // destruct the Peer. Sometimes another thread is still holding a // PeerRef, so the refcount is >= 1. Be careful not to do any // processing here that assumes Peer won't be changed before it's // destructed. PeerRef peer = RemovePeer(nodeid); assert(peer != nullptr); misbehavior = WITH_LOCK(peer->m_misbehavior_mutex, return peer->m_misbehavior_score); m_wtxid_relay_peers -= peer->m_wtxid_relay; assert(m_wtxid_relay_peers >= 0); } CNodeState *state = State(nodeid); assert(state != nullptr); if (state->fSyncStarted) nSyncStarted--; for (const QueuedBlock& entry : state->vBlocksInFlight) { auto range = mapBlocksInFlight.equal_range(entry.pindex->GetBlockHash()); while (range.first != range.second) { auto [node_id, list_it] = range.first->second; if (node_id != nodeid) { range.first++; } else { range.first = mapBlocksInFlight.erase(range.first); } } } m_orphanage.EraseForPeer(nodeid); m_txrequest.DisconnectedPeer(nodeid); if (m_txreconciliation) m_txreconciliation->ForgetPeer(nodeid); m_num_preferred_download_peers -= state->fPreferredDownload; m_peers_downloading_from -= (!state->vBlocksInFlight.empty()); assert(m_peers_downloading_from >= 0); m_outbound_peers_with_protect_from_disconnect -= state->m_chain_sync.m_protect; assert(m_outbound_peers_with_protect_from_disconnect >= 0); m_node_states.erase(nodeid); if (m_node_states.empty()) { // Do a consistency check after the last peer is removed. assert(mapBlocksInFlight.empty()); assert(m_num_preferred_download_peers == 0); assert(m_peers_downloading_from == 0); assert(m_outbound_peers_with_protect_from_disconnect == 0); assert(m_wtxid_relay_peers == 0); assert(m_txrequest.Size() == 0); assert(m_orphanage.Size() == 0); } } // cs_main if (node.fSuccessfullyConnected && misbehavior == 0 && !node.IsBlockOnlyConn() && !node.IsInboundConn()) { // Only change visible addrman state for full outbound peers. We don't // call Connected() for feeler connections since they don't have // fSuccessfullyConnected set. m_addrman.Connected(node.addr); } { LOCK(m_headers_presync_mutex); m_headers_presync_stats.erase(nodeid); } LogPrint(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid); } bool PeerManagerImpl::HasAllDesirableServiceFlags(ServiceFlags services) const { // Shortcut for (services & GetDesirableServiceFlags(services)) == GetDesirableServiceFlags(services) return !(GetDesirableServiceFlags(services) & (~services)); } ServiceFlags PeerManagerImpl::GetDesirableServiceFlags(ServiceFlags services) const { if (services & NODE_NETWORK_LIMITED) { // Limited peers are desirable when we are close to the tip. if (ApproximateBestBlockDepth() < NODE_NETWORK_LIMITED_ALLOW_CONN_BLOCKS) { return ServiceFlags(NODE_NETWORK_LIMITED | NODE_WITNESS); } } return ServiceFlags(NODE_NETWORK | NODE_WITNESS); } PeerRef PeerManagerImpl::GetPeerRef(NodeId id) const { LOCK(m_peer_mutex); auto it = m_peer_map.find(id); return it != m_peer_map.end() ? it->second : nullptr; } PeerRef PeerManagerImpl::RemovePeer(NodeId id) { PeerRef ret; LOCK(m_peer_mutex); auto it = m_peer_map.find(id); if (it != m_peer_map.end()) { ret = std::move(it->second); m_peer_map.erase(it); } return ret; } bool PeerManagerImpl::GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) const { { LOCK(cs_main); const CNodeState* state = State(nodeid); if (state == nullptr) return false; stats.nSyncHeight = state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1; stats.nCommonHeight = state->pindexLastCommonBlock ? state->pindexLastCommonBlock->nHeight : -1; for (const QueuedBlock& queue : state->vBlocksInFlight) { if (queue.pindex) stats.vHeightInFlight.push_back(queue.pindex->nHeight); } } PeerRef peer = GetPeerRef(nodeid); if (peer == nullptr) return false; stats.their_services = peer->m_their_services; stats.m_starting_height = peer->m_starting_height; // It is common for nodes with good ping times to suddenly become lagged, // due to a new block arriving or other large transfer. // Merely reporting pingtime might fool the caller into thinking the node was still responsive, // since pingtime does not update until the ping is complete, which might take a while. // So, if a ping is taking an unusually long time in flight, // the caller can immediately detect that this is happening. auto ping_wait{0us}; if ((0 != peer->m_ping_nonce_sent) && (0 != peer->m_ping_start.load().count())) { ping_wait = GetTime() - peer->m_ping_start.load(); } if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { stats.m_relay_txs = WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs); stats.m_fee_filter_received = tx_relay->m_fee_filter_received.load(); } else { stats.m_relay_txs = false; stats.m_fee_filter_received = 0; } stats.m_ping_wait = ping_wait; stats.m_addr_processed = peer->m_addr_processed.load(); stats.m_addr_rate_limited = peer->m_addr_rate_limited.load(); stats.m_addr_relay_enabled = peer->m_addr_relay_enabled.load(); { LOCK(peer->m_headers_sync_mutex); if (peer->m_headers_sync) { stats.presync_height = peer->m_headers_sync->GetPresyncHeight(); } } stats.time_offset = peer->m_time_offset; return true; } PeerManagerInfo PeerManagerImpl::GetInfo() const { return PeerManagerInfo{ .median_outbound_time_offset = m_outbound_time_offsets.Median(), .ignores_incoming_txs = m_opts.ignore_incoming_txs, }; } void PeerManagerImpl::AddToCompactExtraTransactions(const CTransactionRef& tx) { if (m_opts.max_extra_txs <= 0) return; if (!vExtraTxnForCompact.size()) vExtraTxnForCompact.resize(m_opts.max_extra_txs); vExtraTxnForCompact[vExtraTxnForCompactIt] = tx; vExtraTxnForCompactIt = (vExtraTxnForCompactIt + 1) % m_opts.max_extra_txs; } void PeerManagerImpl::Misbehaving(Peer& peer, int howmuch, const std::string& message) { assert(howmuch > 0); LOCK(peer.m_misbehavior_mutex); const int score_before{peer.m_misbehavior_score}; peer.m_misbehavior_score += howmuch; const int score_now{peer.m_misbehavior_score}; const std::string message_prefixed = message.empty() ? "" : (": " + message); std::string warning; if (score_now >= DISCOURAGEMENT_THRESHOLD && score_before < DISCOURAGEMENT_THRESHOLD) { warning = " DISCOURAGE THRESHOLD EXCEEDED"; peer.m_should_discourage = true; } LogPrint(BCLog::NET, "Misbehaving: peer=%d (%d -> %d)%s%s\n", peer.m_id, score_before, score_now, warning, message_prefixed); } bool PeerManagerImpl::MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& state, bool via_compact_block, const std::string& message) { PeerRef peer{GetPeerRef(nodeid)}; switch (state.GetResult()) { case BlockValidationResult::BLOCK_RESULT_UNSET: break; case BlockValidationResult::BLOCK_HEADER_LOW_WORK: // We didn't try to process the block because the header chain may have // too little work. break; // The node is providing invalid data: case BlockValidationResult::BLOCK_CONSENSUS: case BlockValidationResult::BLOCK_MUTATED: if (!via_compact_block) { if (peer) Misbehaving(*peer, 100, message); return true; } break; case BlockValidationResult::BLOCK_CACHED_INVALID: { LOCK(cs_main); CNodeState *node_state = State(nodeid); if (node_state == nullptr) { break; } // Discourage outbound (but not inbound) peers if on an invalid chain. // Exempt HB compact block peers. Manual connections are always protected from discouragement. if (!via_compact_block && !node_state->m_is_inbound) { if (peer) Misbehaving(*peer, 100, message); return true; } break; } case BlockValidationResult::BLOCK_INVALID_HEADER: case BlockValidationResult::BLOCK_CHECKPOINT: case BlockValidationResult::BLOCK_INVALID_PREV: if (peer) Misbehaving(*peer, 100, message); return true; // Conflicting (but not necessarily invalid) data or different policy: case BlockValidationResult::BLOCK_MISSING_PREV: // TODO: Handle this much more gracefully (10 DoS points is super arbitrary) if (peer) Misbehaving(*peer, 10, message); return true; case BlockValidationResult::BLOCK_RECENT_CONSENSUS_CHANGE: case BlockValidationResult::BLOCK_TIME_FUTURE: break; } if (message != "") { LogPrint(BCLog::NET, "peer=%d: %s\n", nodeid, message); } return false; } bool PeerManagerImpl::MaybePunishNodeForTx(NodeId nodeid, const TxValidationState& state) { PeerRef peer{GetPeerRef(nodeid)}; switch (state.GetResult()) { case TxValidationResult::TX_RESULT_UNSET: break; // The node is providing invalid data: case TxValidationResult::TX_CONSENSUS: if (peer) Misbehaving(*peer, 100, ""); return true; // Conflicting (but not necessarily invalid) data or different policy: case TxValidationResult::TX_RECENT_CONSENSUS_CHANGE: case TxValidationResult::TX_INPUTS_NOT_STANDARD: case TxValidationResult::TX_NOT_STANDARD: case TxValidationResult::TX_MISSING_INPUTS: case TxValidationResult::TX_PREMATURE_SPEND: case TxValidationResult::TX_WITNESS_MUTATED: case TxValidationResult::TX_WITNESS_STRIPPED: case TxValidationResult::TX_CONFLICT: case TxValidationResult::TX_MEMPOOL_POLICY: case TxValidationResult::TX_NO_MEMPOOL: case TxValidationResult::TX_RECONSIDERABLE: case TxValidationResult::TX_UNKNOWN: break; } return false; } bool PeerManagerImpl::BlockRequestAllowed(const CBlockIndex* pindex) { AssertLockHeld(cs_main); if (m_chainman.ActiveChain().Contains(pindex)) return true; return pindex->IsValid(BLOCK_VALID_SCRIPTS) && (m_chainman.m_best_header != nullptr) && (m_chainman.m_best_header->GetBlockTime() - pindex->GetBlockTime() < STALE_RELAY_AGE_LIMIT) && (GetBlockProofEquivalentTime(*m_chainman.m_best_header, *pindex, *m_chainman.m_best_header, m_chainparams.GetConsensus()) < STALE_RELAY_AGE_LIMIT); } std::optional PeerManagerImpl::FetchBlock(NodeId peer_id, const CBlockIndex& block_index) { if (m_chainman.m_blockman.LoadingBlocks()) return "Loading blocks ..."; // Ensure this peer exists and hasn't been disconnected PeerRef peer = GetPeerRef(peer_id); if (peer == nullptr) return "Peer does not exist"; // Ignore pre-segwit peers if (!CanServeWitnesses(*peer)) return "Pre-SegWit peer"; LOCK(cs_main); // Forget about all prior requests RemoveBlockRequest(block_index.GetBlockHash(), std::nullopt); // Mark block as in-flight if (!BlockRequested(peer_id, block_index)) return "Already requested from this peer"; // Construct message to request the block const uint256& hash{block_index.GetBlockHash()}; std::vector invs{CInv(MSG_BLOCK | MSG_WITNESS_FLAG, hash)}; // Send block request message to the peer bool success = m_connman.ForNode(peer_id, [this, &invs](CNode* node) { this->MakeAndPushMessage(*node, NetMsgType::GETDATA, invs); return true; }); if (!success) return "Peer not fully connected"; LogPrint(BCLog::NET, "Requesting block %s from peer=%d\n", hash.ToString(), peer_id); return std::nullopt; } std::unique_ptr PeerManager::make(CConnman& connman, AddrMan& addrman, BanMan* banman, ChainstateManager& chainman, CTxMemPool& pool, Options opts) { return std::make_unique(connman, addrman, banman, chainman, pool, opts); } PeerManagerImpl::PeerManagerImpl(CConnman& connman, AddrMan& addrman, BanMan* banman, ChainstateManager& chainman, CTxMemPool& pool, Options opts) : m_rng{opts.deterministic_rng}, m_fee_filter_rounder{CFeeRate{DEFAULT_MIN_RELAY_TX_FEE}, m_rng}, m_chainparams(chainman.GetParams()), m_connman(connman), m_addrman(addrman), m_banman(banman), m_chainman(chainman), m_mempool(pool), m_opts{opts} { // While Erlay support is incomplete, it must be enabled explicitly via -txreconciliation. // This argument can go away after Erlay support is complete. if (opts.reconcile_txs) { m_txreconciliation = std::make_unique(TXRECONCILIATION_VERSION); } } void PeerManagerImpl::StartScheduledTasks(CScheduler& scheduler) { // Stale tip checking and peer eviction are on two different timers, but we // don't want them to get out of sync due to drift in the scheduler, so we // combine them in one function and schedule at the quicker (peer-eviction) // timer. static_assert(EXTRA_PEER_CHECK_INTERVAL < STALE_CHECK_INTERVAL, "peer eviction timer should be less than stale tip check timer"); scheduler.scheduleEvery([this] { this->CheckForStaleTipAndEvictPeers(); }, std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL}); // schedule next run for 10-15 minutes in the future const std::chrono::milliseconds delta = 10min + GetRandMillis(5min); scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta); } /** * Evict orphan txn pool entries based on a newly connected * block, remember the recently confirmed transactions, and delete tracked * announcements for them. Also save the time of the last tip update and * possibly reduce dynamic block stalling timeout. */ void PeerManagerImpl::BlockConnected( ChainstateRole role, const std::shared_ptr& pblock, const CBlockIndex* pindex) { // Update this for all chainstate roles so that we don't mistakenly see peers // helping us do background IBD as having a stale tip. m_last_tip_update = GetTime(); // In case the dynamic timeout was doubled once or more, reduce it slowly back to its default value auto stalling_timeout = m_block_stalling_timeout.load(); Assume(stalling_timeout >= BLOCK_STALLING_TIMEOUT_DEFAULT); if (stalling_timeout != BLOCK_STALLING_TIMEOUT_DEFAULT) { const auto new_timeout = std::max(std::chrono::duration_cast(stalling_timeout * 0.85), BLOCK_STALLING_TIMEOUT_DEFAULT); if (m_block_stalling_timeout.compare_exchange_strong(stalling_timeout, new_timeout)) { LogPrint(BCLog::NET, "Decreased stalling timeout to %d seconds\n", count_seconds(new_timeout)); } } // The following task can be skipped since we don't maintain a mempool for // the ibd/background chainstate. if (role == ChainstateRole::BACKGROUND) { return; } m_orphanage.EraseForBlock(*pblock); { LOCK(m_recent_confirmed_transactions_mutex); for (const auto& ptx : pblock->vtx) { m_recent_confirmed_transactions.insert(ptx->GetHash().ToUint256()); if (ptx->HasWitness()) { m_recent_confirmed_transactions.insert(ptx->GetWitnessHash().ToUint256()); } } } { LOCK(cs_main); for (const auto& ptx : pblock->vtx) { m_txrequest.ForgetTxHash(ptx->GetHash()); m_txrequest.ForgetTxHash(ptx->GetWitnessHash()); } } } void PeerManagerImpl::BlockDisconnected(const std::shared_ptr &block, const CBlockIndex* pindex) { // To avoid relay problems with transactions that were previously // confirmed, clear our filter of recently confirmed transactions whenever // there's a reorg. // This means that in a 1-block reorg (where 1 block is disconnected and // then another block reconnected), our filter will drop to having only one // block's worth of transactions in it, but that should be fine, since // presumably the most common case of relaying a confirmed transaction // should be just after a new block containing it is found. LOCK(m_recent_confirmed_transactions_mutex); m_recent_confirmed_transactions.reset(); } /** * Maintain state about the best-seen block and fast-announce a compact block * to compatible peers. */ void PeerManagerImpl::NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr& pblock) { auto pcmpctblock = std::make_shared(*pblock); LOCK(cs_main); if (pindex->nHeight <= m_highest_fast_announce) return; m_highest_fast_announce = pindex->nHeight; if (!DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) return; uint256 hashBlock(pblock->GetHash()); const std::shared_future lazy_ser{ std::async(std::launch::deferred, [&] { return NetMsg::Make(NetMsgType::CMPCTBLOCK, *pcmpctblock); })}; { auto most_recent_block_txs = std::make_unique>(); for (const auto& tx : pblock->vtx) { most_recent_block_txs->emplace(tx->GetHash(), tx); most_recent_block_txs->emplace(tx->GetWitnessHash(), tx); } LOCK(m_most_recent_block_mutex); m_most_recent_block_hash = hashBlock; m_most_recent_block = pblock; m_most_recent_compact_block = pcmpctblock; m_most_recent_block_txs = std::move(most_recent_block_txs); } m_connman.ForEachNode([this, pindex, &lazy_ser, &hashBlock](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); if (pnode->GetCommonVersion() < INVALID_CB_NO_BAN_VERSION || pnode->fDisconnect) return; ProcessBlockAvailability(pnode->GetId()); CNodeState &state = *State(pnode->GetId()); // If the peer has, or we announced to them the previous block already, // but we don't think they have this one, go ahead and announce it if (state.m_requested_hb_cmpctblocks && !PeerHasHeader(&state, pindex) && PeerHasHeader(&state, pindex->pprev)) { LogPrint(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n", "PeerManager::NewPoWValidBlock", hashBlock.ToString(), pnode->GetId()); const CSerializedNetMsg& ser_cmpctblock{lazy_ser.get()}; PushMessage(*pnode, ser_cmpctblock.Copy()); state.pindexBestHeaderSent = pindex; } }); } /** * Update our best height and announce any block hashes which weren't previously * in m_chainman.ActiveChain() to our peers. */ void PeerManagerImpl::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) { SetBestBlock(pindexNew->nHeight, std::chrono::seconds{pindexNew->GetBlockTime()}); // Don't relay inventory during initial block download. if (fInitialDownload) return; // Find the hashes of all blocks that weren't previously in the best chain. std::vector vHashes; const CBlockIndex *pindexToAnnounce = pindexNew; while (pindexToAnnounce != pindexFork) { vHashes.push_back(pindexToAnnounce->GetBlockHash()); pindexToAnnounce = pindexToAnnounce->pprev; if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) { // Limit announcements in case of a huge reorganization. // Rely on the peer's synchronization mechanism in that case. break; } } { LOCK(m_peer_mutex); for (auto& it : m_peer_map) { Peer& peer = *it.second; LOCK(peer.m_block_inv_mutex); for (const uint256& hash : reverse_iterate(vHashes)) { peer.m_blocks_for_headers_relay.push_back(hash); } } } m_connman.WakeMessageHandler(); } /** * Handle invalid block rejection and consequent peer discouragement, maintain which * peers announce compact blocks. */ void PeerManagerImpl::BlockChecked(const CBlock& block, const BlockValidationState& state) { LOCK(cs_main); const uint256 hash(block.GetHash()); std::map>::iterator it = mapBlockSource.find(hash); // If the block failed validation, we know where it came from and we're still connected // to that peer, maybe punish. if (state.IsInvalid() && it != mapBlockSource.end() && State(it->second.first)) { MaybePunishNodeForBlock(/*nodeid=*/ it->second.first, state, /*via_compact_block=*/ !it->second.second); } // Check that: // 1. The block is valid // 2. We're not in initial block download // 3. This is currently the best block we're aware of. We haven't updated // the tip yet so we have no way to check this directly here. Instead we // just check that there are currently no other blocks in flight. else if (state.IsValid() && !m_chainman.IsInitialBlockDownload() && mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) { if (it != mapBlockSource.end()) { MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first); } } if (it != mapBlockSource.end()) mapBlockSource.erase(it); } ////////////////////////////////////////////////////////////////////////////// // // Messages // bool PeerManagerImpl::AlreadyHaveTx(const GenTxid& gtxid, bool include_reconsiderable) { if (m_chainman.ActiveChain().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 = m_chainman.ActiveChain().Tip()->GetBlockHash(); m_recent_rejects.reset(); m_recent_rejects_reconsiderable.reset(); } const uint256& hash = gtxid.GetHash(); if (m_orphanage.HaveTx(gtxid)) return true; if (include_reconsiderable && m_recent_rejects_reconsiderable.contains(hash)) return true; { LOCK(m_recent_confirmed_transactions_mutex); if (m_recent_confirmed_transactions.contains(hash)) return true; } return m_recent_rejects.contains(hash) || m_mempool.exists(gtxid); } bool PeerManagerImpl::AlreadyHaveBlock(const uint256& block_hash) { return m_chainman.m_blockman.LookupBlockIndex(block_hash) != nullptr; } void PeerManagerImpl::SendPings() { LOCK(m_peer_mutex); for(auto& it : m_peer_map) it.second->m_ping_queued = true; } void PeerManagerImpl::RelayTransaction(const uint256& txid, const uint256& wtxid) { LOCK(m_peer_mutex); for(auto& it : m_peer_map) { Peer& peer = *it.second; auto tx_relay = peer.GetTxRelay(); if (!tx_relay) continue; LOCK(tx_relay->m_tx_inventory_mutex); // Only queue transactions for announcement once the version handshake // is completed. The time of arrival for these transactions is // otherwise at risk of leaking to a spy, if the spy is able to // distinguish transactions received during the handshake from the rest // in the announcement. if (tx_relay->m_next_inv_send_time == 0s) continue; const uint256& hash{peer.m_wtxid_relay ? wtxid : txid}; if (!tx_relay->m_tx_inventory_known_filter.contains(hash)) { tx_relay->m_tx_inventory_to_send.insert(hash); } }; } void PeerManagerImpl::RelayAddress(NodeId originator, const CAddress& addr, bool fReachable) { // We choose the same nodes within a given 24h window (if the list of connected // nodes does not change) and we don't relay to nodes that already know an // address. So within 24h we will likely relay a given address once. This is to // prevent a peer from unjustly giving their address better propagation by sending // it to us repeatedly. if (!fReachable && !addr.IsRelayable()) return; // Relay to a limited number of other nodes // Use deterministic randomness to send to the same nodes for 24 hours // at a time so the m_addr_knowns of the chosen nodes prevent repeats const uint64_t hash_addr{CServiceHash(0, 0)(addr)}; const auto current_time{GetTime()}; // Adding address hash makes exact rotation time different per address, while preserving periodicity. const uint64_t time_addr{(static_cast(count_seconds(current_time)) + hash_addr) / count_seconds(ROTATE_ADDR_RELAY_DEST_INTERVAL)}; const CSipHasher hasher{m_connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY) .Write(hash_addr) .Write(time_addr)}; // Relay reachable addresses to 2 peers. Unreachable addresses are relayed randomly to 1 or 2 peers. unsigned int nRelayNodes = (fReachable || (hasher.Finalize() & 1)) ? 2 : 1; std::array, 2> best{{{0, nullptr}, {0, nullptr}}}; assert(nRelayNodes <= best.size()); LOCK(m_peer_mutex); for (auto& [id, peer] : m_peer_map) { if (peer->m_addr_relay_enabled && id != originator && IsAddrCompatible(*peer, addr)) { uint64_t hashKey = CSipHasher(hasher).Write(id).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, peer.get()); break; } } } }; for (unsigned int i = 0; i < nRelayNodes && best[i].first != 0; i++) { PushAddress(*best[i].second, addr); } } void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv& inv) { std::shared_ptr a_recent_block; std::shared_ptr a_recent_compact_block; { LOCK(m_most_recent_block_mutex); a_recent_block = m_most_recent_block; a_recent_compact_block = m_most_recent_compact_block; } bool need_activate_chain = false; { LOCK(cs_main); const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash); if (pindex) { if (pindex->HaveNumChainTxs() && !pindex->IsValid(BLOCK_VALID_SCRIPTS) && pindex->IsValid(BLOCK_VALID_TREE)) { // If we have the block and all of its parents, but have not yet validated it, // we might be in the middle of connecting it (ie in the unlock of cs_main // before ActivateBestChain but after AcceptBlock). // In this case, we need to run ActivateBestChain prior to checking the relay // conditions below. need_activate_chain = true; } } } // release cs_main before calling ActivateBestChain if (need_activate_chain) { BlockValidationState state; if (!m_chainman.ActiveChainstate().ActivateBestChain(state, a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", state.ToString()); } } LOCK(cs_main); const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash); if (!pindex) { return; } if (!BlockRequestAllowed(pindex)) { LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom.GetId()); return; } // disconnect node in case we have reached the outbound limit for serving historical blocks if (m_connman.OutboundTargetReached(true) && (((m_chainman.m_best_header != nullptr) && (m_chainman.m_best_header->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.IsMsgFilteredBlk()) && !pfrom.HasPermission(NetPermissionFlags::Download) // nodes with the download permission may exceed target ) { LogPrint(BCLog::NET, "historical block serving limit reached, disconnect peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } // Avoid leaking prune-height by never sending blocks below the NODE_NETWORK_LIMITED threshold if (!pfrom.HasPermission(NetPermissionFlags::NoBan) && ( (((peer.m_our_services & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((peer.m_our_services & NODE_NETWORK) != NODE_NETWORK) && (m_chainman.ActiveChain().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, disconnect peer=%d\n", pfrom.GetId()); //disconnect node and prevent it from stalling (would otherwise wait for the missing block) pfrom.fDisconnect = true; return; } // Pruned nodes may have deleted the block, so check whether // it's available before trying to send. if (!(pindex->nStatus & BLOCK_HAVE_DATA)) { return; } std::shared_ptr pblock; if (a_recent_block && a_recent_block->GetHash() == pindex->GetBlockHash()) { pblock = a_recent_block; } else if (inv.IsMsgWitnessBlk()) { // Fast-path: in this case it is possible to serve the block directly from disk, // as the network format matches the format on disk std::vector block_data; if (!m_chainman.m_blockman.ReadRawBlockFromDisk(block_data, pindex->GetBlockPos())) { assert(!"cannot load block from disk"); } MakeAndPushMessage(pfrom, NetMsgType::BLOCK, Span{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 (!m_chainman.m_blockman.ReadBlockFromDisk(*pblockRead, *pindex)) { assert(!"cannot load block from disk"); } pblock = pblockRead; } if (pblock) { if (inv.IsMsgBlk()) { MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_NO_WITNESS(*pblock)); } else if (inv.IsMsgWitnessBlk()) { MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_WITH_WITNESS(*pblock)); } else if (inv.IsMsgFilteredBlk()) { bool sendMerkleBlock = false; CMerkleBlock merkleBlock; if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) { LOCK(tx_relay->m_bloom_filter_mutex); if (tx_relay->m_bloom_filter) { sendMerkleBlock = true; merkleBlock = CMerkleBlock(*pblock, *tx_relay->m_bloom_filter); } } if (sendMerkleBlock) { MakeAndPushMessage(pfrom, 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) MakeAndPushMessage(pfrom, NetMsgType::TX, TX_NO_WITNESS(*pblock->vtx[pair.first])); } // else // no response } else if (inv.IsMsgCmpctBlk()) { // If a peer is asking for old blocks, we're almost guaranteed // they won't have a useful mempool to match against a compact block, // and we don't feel like constructing the object for them, so // instead we respond with the full, non-compact block. if (CanDirectFetch() && pindex->nHeight >= m_chainman.ActiveChain().Height() - MAX_CMPCTBLOCK_DEPTH) { if (a_recent_compact_block && a_recent_compact_block->header.GetHash() == pindex->GetBlockHash()) { MakeAndPushMessage(pfrom, NetMsgType::CMPCTBLOCK, *a_recent_compact_block); } else { CBlockHeaderAndShortTxIDs cmpctblock{*pblock}; MakeAndPushMessage(pfrom, NetMsgType::CMPCTBLOCK, cmpctblock); } } else { MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_WITH_WITNESS(*pblock)); } } } { LOCK(peer.m_block_inv_mutex); // Trigger the peer node to send a getblocks request for the next batch of inventory if (inv.hash == peer.m_continuation_block) { // Send immediately. This must send even if redundant, // and we want it right after the last block so they don't // wait for other stuff first. std::vector vInv; vInv.emplace_back(MSG_BLOCK, m_chainman.ActiveChain().Tip()->GetBlockHash()); MakeAndPushMessage(pfrom, NetMsgType::INV, vInv); peer.m_continuation_block.SetNull(); } } } CTransactionRef PeerManagerImpl::FindTxForGetData(const Peer::TxRelay& tx_relay, const GenTxid& gtxid) { // If a tx was in the mempool prior to the last INV for this peer, permit the request. auto txinfo = m_mempool.info_for_relay(gtxid, tx_relay.m_last_inv_sequence); if (txinfo.tx) { return std::move(txinfo.tx); } // Or it might be from the most recent block { LOCK(m_most_recent_block_mutex); if (m_most_recent_block_txs != nullptr) { auto it = m_most_recent_block_txs->find(gtxid.GetHash()); if (it != m_most_recent_block_txs->end()) return it->second; } } return {}; } void PeerManagerImpl::ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic& interruptMsgProc) { AssertLockNotHeld(cs_main); auto tx_relay = peer.GetTxRelay(); std::deque::iterator it = peer.m_getdata_requests.begin(); std::vector vNotFound; // Process as many TX items from the front of the getdata queue as // possible, since they're common and it's efficient to batch process // them. while (it != peer.m_getdata_requests.end() && it->IsGenTxMsg()) { if (interruptMsgProc) return; // The send buffer provides backpressure. If there's no space in // the buffer, pause processing until the next call. if (pfrom.fPauseSend) break; const CInv &inv = *it++; if (tx_relay == nullptr) { // Ignore GETDATA requests for transactions from block-relay-only // peers and peers that asked us not to announce transactions. continue; } CTransactionRef tx = FindTxForGetData(*tx_relay, ToGenTxid(inv)); if (tx) { // WTX and WITNESS_TX imply we serialize with witness const auto maybe_with_witness = (inv.IsMsgTx() ? TX_NO_WITNESS : TX_WITH_WITNESS); MakeAndPushMessage(pfrom, NetMsgType::TX, maybe_with_witness(*tx)); m_mempool.RemoveUnbroadcastTx(tx->GetHash()); } else { vNotFound.push_back(inv); } } // Only process one BLOCK item per call, since they're uncommon and can be // expensive to process. if (it != peer.m_getdata_requests.end() && !pfrom.fPauseSend) { const CInv &inv = *it++; if (inv.IsGenBlkMsg()) { ProcessGetBlockData(pfrom, peer, inv); } // else: If the first item on the queue is an unknown type, we erase it // and continue processing the queue on the next call. } peer.m_getdata_requests.erase(peer.m_getdata_requests.begin(), it); if (!vNotFound.empty()) { // Let the peer know that we didn't find what it asked for, so it doesn't // have to wait around forever. // SPV clients care about this message: it's needed when they are // recursively walking the dependencies of relevant unconfirmed // transactions. SPV clients want to do that because they want to know // about (and store and rebroadcast and risk analyze) the dependencies // of transactions relevant to them, without having to download the // entire memory pool. // Also, other nodes can use these messages to automatically request a // transaction from some other peer that announced 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. MakeAndPushMessage(pfrom, NetMsgType::NOTFOUND, vNotFound); } } uint32_t PeerManagerImpl::GetFetchFlags(const Peer& peer) const { uint32_t nFetchFlags = 0; if (CanServeWitnesses(peer)) { nFetchFlags |= MSG_WITNESS_FLAG; } return nFetchFlags; } void PeerManagerImpl::SendBlockTransactions(CNode& pfrom, Peer& peer, const CBlock& block, const BlockTransactionsRequest& req) { BlockTransactions resp(req); for (size_t i = 0; i < req.indexes.size(); i++) { if (req.indexes[i] >= block.vtx.size()) { Misbehaving(peer, 100, "getblocktxn with out-of-bounds tx indices"); return; } resp.txn[i] = block.vtx[req.indexes[i]]; } MakeAndPushMessage(pfrom, NetMsgType::BLOCKTXN, resp); } bool PeerManagerImpl::CheckHeadersPoW(const std::vector& headers, const Consensus::Params& consensusParams, Peer& peer) { // Do these headers have proof-of-work matching what's claimed? if (!HasValidProofOfWork(headers, consensusParams)) { Misbehaving(peer, 100, "header with invalid proof of work"); return false; } // Are these headers connected to each other? if (!CheckHeadersAreContinuous(headers)) { Misbehaving(peer, 20, "non-continuous headers sequence"); return false; } return true; } arith_uint256 PeerManagerImpl::GetAntiDoSWorkThreshold() { arith_uint256 near_chaintip_work = 0; LOCK(cs_main); if (m_chainman.ActiveChain().Tip() != nullptr) { const CBlockIndex *tip = m_chainman.ActiveChain().Tip(); // Use a 144 block buffer, so that we'll accept headers that fork from // near our tip. near_chaintip_work = tip->nChainWork - std::min(144*GetBlockProof(*tip), tip->nChainWork); } return std::max(near_chaintip_work, m_chainman.MinimumChainWork()); } /** * Special handling for unconnecting headers that might be part of a block * announcement. * * We'll send a getheaders message in response to try to connect the chain. * * The peer can send up to MAX_NUM_UNCONNECTING_HEADERS_MSGS in a row that * don't connect before given DoS points. * * Once a headers message is received that is valid and does connect, * m_num_unconnecting_headers_msgs gets reset back to 0. */ void PeerManagerImpl::HandleFewUnconnectingHeaders(CNode& pfrom, Peer& peer, const std::vector& headers) { peer.m_num_unconnecting_headers_msgs++; // Try to fill in the missing headers. const CBlockIndex* best_header{WITH_LOCK(cs_main, return m_chainman.m_best_header)}; if (MaybeSendGetHeaders(pfrom, GetLocator(best_header), peer)) { LogPrint(BCLog::NET, "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d, m_num_unconnecting_headers_msgs=%d)\n", headers[0].GetHash().ToString(), headers[0].hashPrevBlock.ToString(), best_header->nHeight, pfrom.GetId(), peer.m_num_unconnecting_headers_msgs); } // 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. WITH_LOCK(cs_main, UpdateBlockAvailability(pfrom.GetId(), headers.back().GetHash())); // The peer may just be broken, so periodically assign DoS points if this // condition persists. if (peer.m_num_unconnecting_headers_msgs % MAX_NUM_UNCONNECTING_HEADERS_MSGS == 0) { Misbehaving(peer, 20, strprintf("%d non-connecting headers", peer.m_num_unconnecting_headers_msgs)); } } bool PeerManagerImpl::CheckHeadersAreContinuous(const std::vector& headers) const { uint256 hashLastBlock; for (const CBlockHeader& header : headers) { if (!hashLastBlock.IsNull() && header.hashPrevBlock != hashLastBlock) { return false; } hashLastBlock = header.GetHash(); } return true; } bool PeerManagerImpl::IsContinuationOfLowWorkHeadersSync(Peer& peer, CNode& pfrom, std::vector& headers) { if (peer.m_headers_sync) { auto result = peer.m_headers_sync->ProcessNextHeaders(headers, headers.size() == MAX_HEADERS_RESULTS); if (result.request_more) { auto locator = peer.m_headers_sync->NextHeadersRequestLocator(); // If we were instructed to ask for a locator, it should not be empty. Assume(!locator.vHave.empty()); if (!locator.vHave.empty()) { // It should be impossible for the getheaders request to fail, // because we should have cleared the last getheaders timestamp // when processing the headers that triggered this call. But // it may be possible to bypass this via compactblock // processing, so check the result before logging just to be // safe. bool sent_getheaders = MaybeSendGetHeaders(pfrom, locator, peer); if (sent_getheaders) { LogPrint(BCLog::NET, "more getheaders (from %s) to peer=%d\n", locator.vHave.front().ToString(), pfrom.GetId()); } else { LogPrint(BCLog::NET, "error sending next getheaders (from %s) to continue sync with peer=%d\n", locator.vHave.front().ToString(), pfrom.GetId()); } } } if (peer.m_headers_sync->GetState() == HeadersSyncState::State::FINAL) { peer.m_headers_sync.reset(nullptr); // Delete this peer's entry in m_headers_presync_stats. // If this is m_headers_presync_bestpeer, it will be replaced later // by the next peer that triggers the else{} branch below. LOCK(m_headers_presync_mutex); m_headers_presync_stats.erase(pfrom.GetId()); } else { // Build statistics for this peer's sync. HeadersPresyncStats stats; stats.first = peer.m_headers_sync->GetPresyncWork(); if (peer.m_headers_sync->GetState() == HeadersSyncState::State::PRESYNC) { stats.second = {peer.m_headers_sync->GetPresyncHeight(), peer.m_headers_sync->GetPresyncTime()}; } // Update statistics in stats. LOCK(m_headers_presync_mutex); m_headers_presync_stats[pfrom.GetId()] = stats; auto best_it = m_headers_presync_stats.find(m_headers_presync_bestpeer); bool best_updated = false; if (best_it == m_headers_presync_stats.end()) { // If the cached best peer is outdated, iterate over all remaining ones (including // newly updated one) to find the best one. NodeId peer_best{-1}; const HeadersPresyncStats* stat_best{nullptr}; for (const auto& [peer, stat] : m_headers_presync_stats) { if (!stat_best || stat > *stat_best) { peer_best = peer; stat_best = &stat; } } m_headers_presync_bestpeer = peer_best; best_updated = (peer_best == pfrom.GetId()); } else if (best_it->first == pfrom.GetId() || stats > best_it->second) { // pfrom was and remains the best peer, or pfrom just became best. m_headers_presync_bestpeer = pfrom.GetId(); best_updated = true; } if (best_updated && stats.second.has_value()) { // If the best peer updated, and it is in its first phase, signal. m_headers_presync_should_signal = true; } } if (result.success) { // We only overwrite the headers passed in if processing was // successful. headers.swap(result.pow_validated_headers); } return result.success; } // Either we didn't have a sync in progress, or something went wrong // processing these headers, or we are returning headers to the caller to // process. return false; } bool PeerManagerImpl::TryLowWorkHeadersSync(Peer& peer, CNode& pfrom, const CBlockIndex* chain_start_header, std::vector& headers) { // Calculate the claimed total work on this chain. arith_uint256 total_work = chain_start_header->nChainWork + CalculateClaimedHeadersWork(headers); // Our dynamic anti-DoS threshold (minimum work required on a headers chain // before we'll store it) arith_uint256 minimum_chain_work = GetAntiDoSWorkThreshold(); // Avoid DoS via low-difficulty-headers by only processing if the headers // are part of a chain with sufficient work. if (total_work < minimum_chain_work) { // Only try to sync with this peer if their headers message was full; // otherwise they don't have more headers after this so no point in // trying to sync their too-little-work chain. if (headers.size() == MAX_HEADERS_RESULTS) { // Note: we could advance to the last header in this set that is // known to us, rather than starting at the first header (which we // may already have); however this is unlikely to matter much since // ProcessHeadersMessage() already handles the case where all // headers in a received message are already known and are // ancestors of m_best_header or chainActive.Tip(), by skipping // this logic in that case. So even if the first header in this set // of headers is known, some header in this set must be new, so // advancing to the first unknown header would be a small effect. LOCK(peer.m_headers_sync_mutex); peer.m_headers_sync.reset(new HeadersSyncState(peer.m_id, m_chainparams.GetConsensus(), chain_start_header, minimum_chain_work)); // Now a HeadersSyncState object for tracking this synchronization // is created, process the headers using it as normal. Failures are // handled inside of IsContinuationOfLowWorkHeadersSync. (void)IsContinuationOfLowWorkHeadersSync(peer, pfrom, headers); } else { LogPrint(BCLog::NET, "Ignoring low-work chain (height=%u) from peer=%d\n", chain_start_header->nHeight + headers.size(), pfrom.GetId()); } // The peer has not yet given us a chain that meets our work threshold, // so we want to prevent further processing of the headers in any case. headers = {}; return true; } return false; } bool PeerManagerImpl::IsAncestorOfBestHeaderOrTip(const CBlockIndex* header) { if (header == nullptr) { return false; } else if (m_chainman.m_best_header != nullptr && header == m_chainman.m_best_header->GetAncestor(header->nHeight)) { return true; } else if (m_chainman.ActiveChain().Contains(header)) { return true; } return false; } bool PeerManagerImpl::MaybeSendGetHeaders(CNode& pfrom, const CBlockLocator& locator, Peer& peer) { const auto current_time = NodeClock::now(); // Only allow a new getheaders message to go out if we don't have a recent // one already in-flight if (current_time - peer.m_last_getheaders_timestamp > HEADERS_RESPONSE_TIME) { MakeAndPushMessage(pfrom, NetMsgType::GETHEADERS, locator, uint256()); peer.m_last_getheaders_timestamp = current_time; return true; } return false; } /* * Given a new headers tip ending in last_header, potentially request blocks towards that tip. * We require that the given tip have at least as much work as our tip, and for * our current tip to be "close to synced" (see CanDirectFetch()). */ void PeerManagerImpl::HeadersDirectFetchBlocks(CNode& pfrom, const Peer& peer, const CBlockIndex& last_header) { LOCK(cs_main); CNodeState *nodestate = State(pfrom.GetId()); if (CanDirectFetch() && last_header.IsValid(BLOCK_VALID_TREE) && m_chainman.ActiveChain().Tip()->nChainWork <= last_header.nChainWork) { std::vector vToFetch; const CBlockIndex* pindexWalk{&last_header}; // Calculate all the blocks we'd need to switch to last_header, up to a limit. while (pindexWalk && !m_chainman.ActiveChain().Contains(pindexWalk) && vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) { if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) && !IsBlockRequested(pindexWalk->GetBlockHash()) && (!DeploymentActiveAt(*pindexWalk, m_chainman, Consensus::DEPLOYMENT_SEGWIT) || CanServeWitnesses(peer))) { // 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 (!m_chainman.ActiveChain().Contains(pindexWalk)) { LogPrint(BCLog::NET, "Large reorg, won't direct fetch to %s (%d)\n", last_header.GetBlockHash().ToString(), last_header.nHeight); } else { std::vector vGetData; // Download as much as possible, from earliest to latest. for (const CBlockIndex *pindex : reverse_iterate(vToFetch)) { if (nodestate->vBlocksInFlight.size() >= MAX_BLOCKS_IN_TRANSIT_PER_PEER) { // Can't download any more from this peer break; } uint32_t nFetchFlags = GetFetchFlags(peer); vGetData.emplace_back(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash()); BlockRequested(pfrom.GetId(), *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", last_header.GetBlockHash().ToString(), last_header.nHeight); } if (vGetData.size() > 0) { if (!m_opts.ignore_incoming_txs && nodestate->m_provides_cmpctblocks && vGetData.size() == 1 && mapBlocksInFlight.size() == 1 && last_header.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); } MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vGetData); } } } } /** * Given receipt of headers from a peer ending in last_header, along with * whether that header was new and whether the headers message was full, * update the state we keep for the peer. */ void PeerManagerImpl::UpdatePeerStateForReceivedHeaders(CNode& pfrom, Peer& peer, const CBlockIndex& last_header, bool received_new_header, bool may_have_more_headers) { if (peer.m_num_unconnecting_headers_msgs > 0) { LogPrint(BCLog::NET, "peer=%d: resetting m_num_unconnecting_headers_msgs (%d -> 0)\n", pfrom.GetId(), peer.m_num_unconnecting_headers_msgs); } peer.m_num_unconnecting_headers_msgs = 0; LOCK(cs_main); CNodeState *nodestate = State(pfrom.GetId()); UpdateBlockAvailability(pfrom.GetId(), last_header.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 && last_header.nChainWork > m_chainman.ActiveChain().Tip()->nChainWork) { nodestate->m_last_block_announcement = GetTime(); } // 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 (m_chainman.IsInitialBlockDownload() && !may_have_more_headers) { // If the peer has no more headers to give us, then we know we have // their tip. if (nodestate->pindexBestKnownBlock && nodestate->pindexBestKnownBlock->nChainWork < m_chainman.MinimumChainWork()) { // This peer has too little work on their headers chain to help // us sync -- disconnect if it is an outbound disconnection // candidate. // Note: We compare their tip to the minimum chain work (rather than // m_chainman.ActiveChain().Tip()) because we won't start block download // until we have a headers chain that has at least // the minimum chain work, even if a peer has a chain past our tip, // as an anti-DoS measure. if (pfrom.IsOutboundOrBlockRelayConn()) { LogPrintf("Disconnecting outbound peer %d -- headers chain has insufficient work\n", pfrom.GetId()); pfrom.fDisconnect = true; } } } // If this is an outbound full-relay peer, check to see if we should protect // it from the bad/lagging chain logic. // Note that outbound block-relay peers are excluded from this protection, and // thus always subject to eviction under the bad/lagging chain logic. // See ChainSyncTimeoutState. if (!pfrom.fDisconnect && pfrom.IsFullOutboundConn() && nodestate->pindexBestKnownBlock != nullptr) { if (m_outbound_peers_with_protect_from_disconnect < MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT && nodestate->pindexBestKnownBlock->nChainWork >= m_chainman.ActiveChain().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; ++m_outbound_peers_with_protect_from_disconnect; } } } void PeerManagerImpl::ProcessHeadersMessage(CNode& pfrom, Peer& peer, std::vector&& headers, bool via_compact_block) { size_t nCount = headers.size(); if (nCount == 0) { // Nothing interesting. Stop asking this peers for more headers. // If we were in the middle of headers sync, receiving an empty headers // message suggests that the peer suddenly has nothing to give us // (perhaps it reorged to our chain). Clear download state for this peer. LOCK(peer.m_headers_sync_mutex); if (peer.m_headers_sync) { peer.m_headers_sync.reset(nullptr); LOCK(m_headers_presync_mutex); m_headers_presync_stats.erase(pfrom.GetId()); } return; } // Before we do any processing, make sure these pass basic sanity checks. // We'll rely on headers having valid proof-of-work further down, as an // anti-DoS criteria (note: this check is required before passing any // headers into HeadersSyncState). if (!CheckHeadersPoW(headers, m_chainparams.GetConsensus(), peer)) { // Misbehaving() calls are handled within CheckHeadersPoW(), so we can // just return. (Note that even if a header is announced via compact // block, the header itself should be valid, so this type of error can // always be punished.) return; } const CBlockIndex *pindexLast = nullptr; // We'll set already_validated_work to true if these headers are // successfully processed as part of a low-work headers sync in progress // (either in PRESYNC or REDOWNLOAD phase). // If true, this will mean that any headers returned to us (ie during // REDOWNLOAD) can be validated without further anti-DoS checks. bool already_validated_work = false; // If we're in the middle of headers sync, let it do its magic. bool have_headers_sync = false; { LOCK(peer.m_headers_sync_mutex); already_validated_work = IsContinuationOfLowWorkHeadersSync(peer, pfrom, headers); // The headers we passed in may have been: // - untouched, perhaps if no headers-sync was in progress, or some // failure occurred // - erased, such as if the headers were successfully processed and no // additional headers processing needs to take place (such as if we // are still in PRESYNC) // - replaced with headers that are now ready for validation, such as // during the REDOWNLOAD phase of a low-work headers sync. // So just check whether we still have headers that we need to process, // or not. if (headers.empty()) { return; } have_headers_sync = !!peer.m_headers_sync; } // Do these headers connect to something in our block index? const CBlockIndex *chain_start_header{WITH_LOCK(::cs_main, return m_chainman.m_blockman.LookupBlockIndex(headers[0].hashPrevBlock))}; bool headers_connect_blockindex{chain_start_header != nullptr}; if (!headers_connect_blockindex) { if (nCount <= MAX_BLOCKS_TO_ANNOUNCE) { // If this looks like it could be a BIP 130 block announcement, use // special logic for handling headers that don't connect, as this // could be benign. HandleFewUnconnectingHeaders(pfrom, peer, headers); } else { Misbehaving(peer, 10, "invalid header received"); } return; } // If the headers we received are already in memory and an ancestor of // m_best_header or our tip, skip anti-DoS checks. These headers will not // use any more memory (and we are not leaking information that could be // used to fingerprint us). const CBlockIndex *last_received_header{nullptr}; { LOCK(cs_main); last_received_header = m_chainman.m_blockman.LookupBlockIndex(headers.back().GetHash()); if (IsAncestorOfBestHeaderOrTip(last_received_header)) { already_validated_work = true; } } // If our peer has NetPermissionFlags::NoBan privileges, then bypass our // anti-DoS logic (this saves bandwidth when we connect to a trusted peer // on startup). if (pfrom.HasPermission(NetPermissionFlags::NoBan)) { already_validated_work = true; } // At this point, the headers connect to something in our block index. // Do anti-DoS checks to determine if we should process or store for later // processing. if (!already_validated_work && TryLowWorkHeadersSync(peer, pfrom, chain_start_header, headers)) { // If we successfully started a low-work headers sync, then there // should be no headers to process any further. Assume(headers.empty()); return; } // At this point, we have a set of headers with sufficient work on them // which can be processed. // If we don't have the last header, then this peer will have given us // something new (if these headers are valid). bool received_new_header{last_received_header == nullptr}; // Now process all the headers. BlockValidationState state; if (!m_chainman.ProcessNewBlockHeaders(headers, /*min_pow_checked=*/true, state, &pindexLast)) { if (state.IsInvalid()) { MaybePunishNodeForBlock(pfrom.GetId(), state, via_compact_block, "invalid header received"); return; } } assert(pindexLast); // Consider fetching more headers if we are not using our headers-sync mechanism. if (nCount == MAX_HEADERS_RESULTS && !have_headers_sync) { // Headers message had its maximum size; the peer may have more headers. if (MaybeSendGetHeaders(pfrom, GetLocator(pindexLast), peer)) { LogPrint(BCLog::NET, "more getheaders (%d) to end to peer=%d (startheight:%d)\n", pindexLast->nHeight, pfrom.GetId(), peer.m_starting_height); } } UpdatePeerStateForReceivedHeaders(pfrom, peer, *pindexLast, received_new_header, nCount == MAX_HEADERS_RESULTS); // Consider immediately downloading blocks. HeadersDirectFetchBlocks(pfrom, peer, *pindexLast); return; } void PeerManagerImpl::ProcessInvalidTx(NodeId nodeid, const CTransactionRef& ptx, const TxValidationState& state, bool maybe_add_extra_compact_tx) { AssertLockNotHeld(m_peer_mutex); AssertLockHeld(g_msgproc_mutex); AssertLockHeld(cs_main); LogDebug(BCLog::MEMPOOLREJ, "%s (wtxid=%s) from peer=%d was not accepted: %s\n", ptx->GetHash().ToString(), ptx->GetWitnessHash().ToString(), nodeid, state.ToString()); if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) { return; } else if (state.GetResult() != TxValidationResult::TX_WITNESS_STRIPPED) { // We can add the wtxid of this transaction to our reject filter. // Do not add txids of witness transactions or witness-stripped // transactions to the filter, as they can have been malleated; // adding such txids to the reject filter would potentially // interfere with relay of valid transactions from peers that // do not support wtxid-based relay. See // https://github.com/bitcoin/bitcoin/issues/8279 for details. // We can remove this restriction (and always add wtxids to // the filter even for witness stripped transactions) once // wtxid-based relay is broadly deployed. // See also comments in https://github.com/bitcoin/bitcoin/pull/18044#discussion_r443419034 // for concerns around weakening security of unupgraded nodes // if we start doing this too early. if (state.GetResult() == TxValidationResult::TX_RECONSIDERABLE) { // If the result is TX_RECONSIDERABLE, add it to m_recent_rejects_reconsiderable // because we should not download or submit this transaction by itself again, but may // submit it as part of a package later. m_recent_rejects_reconsiderable.insert(ptx->GetWitnessHash().ToUint256()); } else { m_recent_rejects.insert(ptx->GetWitnessHash().ToUint256()); } m_txrequest.ForgetTxHash(ptx->GetWitnessHash()); // If the transaction failed for TX_INPUTS_NOT_STANDARD, // then we know that the witness was irrelevant to the policy // failure, since this check depends only on the txid // (the scriptPubKey being spent is covered by the txid). // Add the txid to the reject filter to prevent repeated // processing of this transaction in the event that child // transactions are later received (resulting in // parent-fetching by txid via the orphan-handling logic). // We only add the txid if it differs from the wtxid, to avoid wasting entries in the // rolling bloom filter. if (state.GetResult() == TxValidationResult::TX_INPUTS_NOT_STANDARD && ptx->HasWitness()) { m_recent_rejects.insert(ptx->GetHash().ToUint256()); m_txrequest.ForgetTxHash(ptx->GetHash()); } if (maybe_add_extra_compact_tx && RecursiveDynamicUsage(*ptx) < 100000) { AddToCompactExtraTransactions(ptx); } } MaybePunishNodeForTx(nodeid, state); // If the tx failed in ProcessOrphanTx, it should be removed from the orphanage unless the // tx was still missing inputs. If the tx was not in the orphanage, EraseTx does nothing and returns 0. if (Assume(state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) && m_orphanage.EraseTx(ptx->GetHash()) > 0) { LogDebug(BCLog::TXPACKAGES, " removed orphan tx %s (wtxid=%s)\n", ptx->GetHash().ToString(), ptx->GetWitnessHash().ToString()); } } void PeerManagerImpl::ProcessValidTx(NodeId nodeid, const CTransactionRef& tx, const std::list& replaced_transactions) { AssertLockNotHeld(m_peer_mutex); AssertLockHeld(g_msgproc_mutex); AssertLockHeld(cs_main); // As this version of the transaction was acceptable, we can forget about any requests for it. // No-op if the tx is not in txrequest. m_txrequest.ForgetTxHash(tx->GetHash()); m_txrequest.ForgetTxHash(tx->GetWitnessHash()); m_orphanage.AddChildrenToWorkSet(*tx); // If it came from the orphanage, remove it. No-op if the tx is not in txorphanage. m_orphanage.EraseTx(tx->GetHash()); LogDebug(BCLog::MEMPOOL, "AcceptToMemoryPool: peer=%d: accepted %s (wtxid=%s) (poolsz %u txn, %u kB)\n", nodeid, tx->GetHash().ToString(), tx->GetWitnessHash().ToString(), m_mempool.size(), m_mempool.DynamicMemoryUsage() / 1000); RelayTransaction(tx->GetHash(), tx->GetWitnessHash()); for (const CTransactionRef& removedTx : replaced_transactions) { AddToCompactExtraTransactions(removedTx); } } void PeerManagerImpl::ProcessPackageResult(const Package& package, const PackageMempoolAcceptResult& package_result, const std::vector& senders) { AssertLockNotHeld(m_peer_mutex); AssertLockHeld(g_msgproc_mutex); AssertLockHeld(cs_main); if (package_result.m_state.IsInvalid()) { m_recent_rejects_reconsiderable.insert(GetPackageHash(package)); } // We currently only expect to process 1-parent-1-child packages. Remove if this changes. if (!Assume(package.size() == 2)) return; // No package results to look through for PCKG_POLICY or PCKG_MEMPOOL_ERROR if (package_result.m_state.GetResult() == PackageValidationResult::PCKG_POLICY || package_result.m_state.GetResult() == PackageValidationResult::PCKG_MEMPOOL_ERROR) return; // Iterate backwards to erase in-package descendants from the orphanage before they become // relevant in AddChildrenToWorkSet. auto package_iter = package.rbegin(); auto senders_iter = senders.rbegin(); while (package_iter != package.rend()) { const auto& tx = *package_iter; const NodeId nodeid = *senders_iter; const auto it_result{package_result.m_tx_results.find(tx->GetWitnessHash())}; if (Assume(it_result != package_result.m_tx_results.end())) { const auto& tx_result = it_result->second; switch (tx_result.m_result_type) { case MempoolAcceptResult::ResultType::VALID: { Assume(tx_result.m_replaced_transactions.has_value()); std::list empty_replacement_list; ProcessValidTx(nodeid, tx, tx_result.m_replaced_transactions.value_or(empty_replacement_list)); break; } case MempoolAcceptResult::ResultType::INVALID: case MempoolAcceptResult::ResultType::DIFFERENT_WITNESS: { // Don't add to vExtraTxnForCompact, as these transactions should have already been // added there when added to the orphanage or rejected for TX_RECONSIDERABLE. // This should be updated if package submission is ever used for transactions // that haven't already been validated before. ProcessInvalidTx(nodeid, tx, tx_result.m_state, /*maybe_add_extra_compact_tx=*/false); break; } case MempoolAcceptResult::ResultType::MEMPOOL_ENTRY: { // AlreadyHaveTx() should be catching transactions that are already in mempool. Assume(false); break; } } } package_iter++; senders_iter++; } } std::optional PeerManagerImpl::Find1P1CPackage(const CTransactionRef& ptx, NodeId nodeid) { AssertLockNotHeld(m_peer_mutex); AssertLockHeld(g_msgproc_mutex); AssertLockHeld(cs_main); const auto& parent_wtxid{ptx->GetWitnessHash()}; Assume(m_recent_rejects_reconsiderable.contains(parent_wtxid.ToUint256())); // Prefer children from this peer. This helps prevent censorship attempts in which an attacker // sends lots of fake children for the parent, and we (unluckily) keep selecting the fake // children instead of the real one provided by the honest peer. const auto cpfp_candidates_same_peer{m_orphanage.GetChildrenFromSamePeer(ptx, nodeid)}; // These children should be sorted from newest to oldest. In the (probably uncommon) case // of children that replace each other, this helps us accept the highest feerate (probably the // most recent) one efficiently. for (const auto& child : cpfp_candidates_same_peer) { Package maybe_cpfp_package{ptx, child}; if (!m_recent_rejects_reconsiderable.contains(GetPackageHash(maybe_cpfp_package))) { return PeerManagerImpl::PackageToValidate{ptx, child, nodeid, nodeid}; } } // If no suitable candidate from the same peer is found, also try children that were provided by // a different peer. This is useful because sometimes multiple peers announce both transactions // to us, and we happen to download them from different peers (we wouldn't have known that these // 2 transactions are related). We still want to find 1p1c packages then. // // If we start tracking all announcers of orphans, we can restrict this logic to parent + child // pairs in which both were provided by the same peer, i.e. delete this step. const auto cpfp_candidates_different_peer{m_orphanage.GetChildrenFromDifferentPeer(ptx, nodeid)}; // Find the first 1p1c that hasn't already been rejected. We randomize the order to not // create a bias that attackers can use to delay package acceptance. // // Create a random permutation of the indices. std::vector tx_indices(cpfp_candidates_different_peer.size()); std::iota(tx_indices.begin(), tx_indices.end(), 0); Shuffle(tx_indices.begin(), tx_indices.end(), m_rng); for (const auto index : tx_indices) { // If we already tried a package and failed for any reason, the combined hash was // cached in m_recent_rejects_reconsiderable. const auto [child_tx, child_sender] = cpfp_candidates_different_peer.at(index); Package maybe_cpfp_package{ptx, child_tx}; if (!m_recent_rejects_reconsiderable.contains(GetPackageHash(maybe_cpfp_package))) { return PeerManagerImpl::PackageToValidate{ptx, child_tx, nodeid, child_sender}; } } return std::nullopt; } bool PeerManagerImpl::ProcessOrphanTx(Peer& peer) { AssertLockHeld(g_msgproc_mutex); LOCK(cs_main); CTransactionRef porphanTx = nullptr; while (CTransactionRef porphanTx = m_orphanage.GetTxToReconsider(peer.m_id)) { const MempoolAcceptResult result = m_chainman.ProcessTransaction(porphanTx); const TxValidationState& state = result.m_state; const Txid& orphanHash = porphanTx->GetHash(); const Wtxid& orphan_wtxid = porphanTx->GetWitnessHash(); if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) { LogPrint(BCLog::TXPACKAGES, " accepted orphan tx %s (wtxid=%s)\n", orphanHash.ToString(), orphan_wtxid.ToString()); Assume(result.m_replaced_transactions.has_value()); std::list empty_replacement_list; ProcessValidTx(peer.m_id, porphanTx, result.m_replaced_transactions.value_or(empty_replacement_list)); return true; } else if (state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) { LogPrint(BCLog::TXPACKAGES, " invalid orphan tx %s (wtxid=%s) from peer=%d. %s\n", orphanHash.ToString(), orphan_wtxid.ToString(), peer.m_id, state.ToString()); if (Assume(state.IsInvalid() && state.GetResult() != TxValidationResult::TX_UNKNOWN && state.GetResult() != TxValidationResult::TX_NO_MEMPOOL && state.GetResult() != TxValidationResult::TX_RESULT_UNSET)) { ProcessInvalidTx(peer.m_id, porphanTx, state, /*maybe_add_extra_compact_tx=*/false); } return true; } } return false; } bool PeerManagerImpl::PrepareBlockFilterRequest(CNode& node, Peer& peer, BlockFilterType filter_type, uint32_t start_height, const uint256& stop_hash, uint32_t max_height_diff, const CBlockIndex*& stop_index, BlockFilterIndex*& filter_index) { const bool supported_filter_type = (filter_type == BlockFilterType::BASIC && (peer.m_our_services & NODE_COMPACT_FILTERS)); if (!supported_filter_type) { LogPrint(BCLog::NET, "peer %d requested unsupported block filter type: %d\n", node.GetId(), static_cast(filter_type)); node.fDisconnect = true; return false; } { LOCK(cs_main); stop_index = m_chainman.m_blockman.LookupBlockIndex(stop_hash); // Check that the stop block exists and the peer would be allowed to fetch it. if (!stop_index || !BlockRequestAllowed(stop_index)) { LogPrint(BCLog::NET, "peer %d requested invalid block hash: %s\n", node.GetId(), stop_hash.ToString()); node.fDisconnect = true; return false; } } uint32_t stop_height = stop_index->nHeight; if (start_height > stop_height) { LogPrint(BCLog::NET, "peer %d sent invalid getcfilters/getcfheaders with " "start height %d and stop height %d\n", node.GetId(), start_height, stop_height); node.fDisconnect = true; return false; } if (stop_height - start_height >= max_height_diff) { LogPrint(BCLog::NET, "peer %d requested too many cfilters/cfheaders: %d / %d\n", node.GetId(), stop_height - start_height + 1, max_height_diff); node.fDisconnect = true; return false; } filter_index = GetBlockFilterIndex(filter_type); if (!filter_index) { LogPrint(BCLog::NET, "Filter index for supported type %s not found\n", BlockFilterTypeName(filter_type)); return false; } return true; } void PeerManagerImpl::ProcessGetCFilters(CNode& node, Peer& peer, DataStream& vRecv) { uint8_t filter_type_ser; uint32_t start_height; uint256 stop_hash; vRecv >> filter_type_ser >> start_height >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(node, peer, filter_type, start_height, stop_hash, MAX_GETCFILTERS_SIZE, stop_index, filter_index)) { return; } std::vector filters; if (!filter_index->LookupFilterRange(start_height, stop_index, filters)) { LogPrint(BCLog::NET, "Failed to find block filter in index: filter_type=%s, start_height=%d, stop_hash=%s\n", BlockFilterTypeName(filter_type), start_height, stop_hash.ToString()); return; } for (const auto& filter : filters) { MakeAndPushMessage(node, NetMsgType::CFILTER, filter); } } void PeerManagerImpl::ProcessGetCFHeaders(CNode& node, Peer& peer, DataStream& vRecv) { uint8_t filter_type_ser; uint32_t start_height; uint256 stop_hash; vRecv >> filter_type_ser >> start_height >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(node, peer, filter_type, start_height, stop_hash, MAX_GETCFHEADERS_SIZE, stop_index, filter_index)) { return; } uint256 prev_header; if (start_height > 0) { const CBlockIndex* const prev_block = stop_index->GetAncestor(static_cast(start_height - 1)); if (!filter_index->LookupFilterHeader(prev_block, prev_header)) { LogPrint(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n", BlockFilterTypeName(filter_type), prev_block->GetBlockHash().ToString()); return; } } std::vector filter_hashes; if (!filter_index->LookupFilterHashRange(start_height, stop_index, filter_hashes)) { LogPrint(BCLog::NET, "Failed to find block filter hashes in index: filter_type=%s, start_height=%d, stop_hash=%s\n", BlockFilterTypeName(filter_type), start_height, stop_hash.ToString()); return; } MakeAndPushMessage(node, NetMsgType::CFHEADERS, filter_type_ser, stop_index->GetBlockHash(), prev_header, filter_hashes); } void PeerManagerImpl::ProcessGetCFCheckPt(CNode& node, Peer& peer, DataStream& vRecv) { uint8_t filter_type_ser; uint256 stop_hash; vRecv >> filter_type_ser >> stop_hash; const BlockFilterType filter_type = static_cast(filter_type_ser); const CBlockIndex* stop_index; BlockFilterIndex* filter_index; if (!PrepareBlockFilterRequest(node, peer, filter_type, /*start_height=*/0, stop_hash, /*max_height_diff=*/std::numeric_limits::max(), stop_index, filter_index)) { return; } std::vector headers(stop_index->nHeight / CFCHECKPT_INTERVAL); // Populate headers. const CBlockIndex* block_index = stop_index; for (int i = headers.size() - 1; i >= 0; i--) { int height = (i + 1) * CFCHECKPT_INTERVAL; block_index = block_index->GetAncestor(height); if (!filter_index->LookupFilterHeader(block_index, headers[i])) { LogPrint(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n", BlockFilterTypeName(filter_type), block_index->GetBlockHash().ToString()); return; } } MakeAndPushMessage(node, NetMsgType::CFCHECKPT, filter_type_ser, stop_index->GetBlockHash(), headers); } void PeerManagerImpl::ProcessBlock(CNode& node, const std::shared_ptr& block, bool force_processing, bool min_pow_checked) { bool new_block{false}; m_chainman.ProcessNewBlock(block, force_processing, min_pow_checked, &new_block); if (new_block) { node.m_last_block_time = GetTime(); // In case this block came from a different peer than we requested // from, we can erase the block request now anyway (as we just stored // this block to disk). LOCK(cs_main); RemoveBlockRequest(block->GetHash(), std::nullopt); } else { LOCK(cs_main); mapBlockSource.erase(block->GetHash()); } } void PeerManagerImpl::ProcessCompactBlockTxns(CNode& pfrom, Peer& peer, const BlockTransactions& block_transactions) { std::shared_ptr pblock = std::make_shared(); bool fBlockRead{false}; { LOCK(cs_main); auto range_flight = mapBlocksInFlight.equal_range(block_transactions.blockhash); size_t already_in_flight = std::distance(range_flight.first, range_flight.second); bool requested_block_from_this_peer{false}; // Multimap ensures ordering of outstanding requests. It's either empty or first in line. bool first_in_flight = already_in_flight == 0 || (range_flight.first->second.first == pfrom.GetId()); while (range_flight.first != range_flight.second) { auto [node_id, block_it] = range_flight.first->second; if (node_id == pfrom.GetId() && block_it->partialBlock) { requested_block_from_this_peer = true; break; } range_flight.first++; } if (!requested_block_from_this_peer) { LogPrint(BCLog::NET, "Peer %d sent us block transactions for block we weren't expecting\n", pfrom.GetId()); return; } PartiallyDownloadedBlock& partialBlock = *range_flight.first->second.second->partialBlock; ReadStatus status = partialBlock.FillBlock(*pblock, block_transactions.txn); if (status == READ_STATUS_INVALID) { RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect Misbehaving(peer, 100, "invalid compact block/non-matching block transactions"); return; } else if (status == READ_STATUS_FAILED) { if (first_in_flight) { // Might have collided, fall back to getdata now :( std::vector invs; invs.emplace_back(MSG_BLOCK | GetFetchFlags(peer), block_transactions.blockhash); MakeAndPushMessage(pfrom, NetMsgType::GETDATA, invs); } else { RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); LogPrint(BCLog::NET, "Peer %d sent us a compact block but it failed to reconstruct, waiting on first download to complete\n", pfrom.GetId()); return; } } else { // Block is either okay, or possibly we received // READ_STATUS_CHECKBLOCK_FAILED. // Note that CheckBlock can only fail for one of a few reasons: // 1. bad-proof-of-work (impossible here, because we've already // accepted the header) // 2. merkleroot doesn't match the transactions given (already // caught in FillBlock with READ_STATUS_FAILED, so // impossible here) // 3. the block is otherwise invalid (eg invalid coinbase, // block is too big, too many legacy sigops, etc). // So if CheckBlock failed, #3 is the only possibility. // Under BIP 152, we don't discourage the peer unless proof of work is // invalid (we don't require all the stateless checks to have // been run). This is handled below, so just treat this as // though the block was successfully read, and rely on the // handling in ProcessNewBlock to ensure the block index is // updated, etc. RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); // it is now an empty pointer fBlockRead = true; // mapBlockSource is used for potentially punishing peers and // updating which peers send us compact blocks, so the race // between here and cs_main in ProcessNewBlock is fine. // BIP 152 permits peers to relay compact blocks after validating // the header only; we should not punish peers if the block turns // out to be invalid. mapBlockSource.emplace(block_transactions.blockhash, std::make_pair(pfrom.GetId(), false)); } } // Don't hold cs_main when we call into ProcessNewBlock if (fBlockRead) { // 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. ProcessBlock(pfrom, pblock, /*force_processing=*/true, /*min_pow_checked=*/true); } return; } void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type, DataStream& vRecv, const std::chrono::microseconds time_received, const std::atomic& interruptMsgProc) { AssertLockHeld(g_msgproc_mutex); LogPrint(BCLog::NET, "received: %s (%u bytes) peer=%d\n", SanitizeString(msg_type), vRecv.size(), pfrom.GetId()); PeerRef peer = GetPeerRef(pfrom.GetId()); if (peer == nullptr) return; if (msg_type == NetMsgType::VERSION) { if (pfrom.nVersion != 0) { LogPrint(BCLog::NET, "redundant version message from peer=%d\n", pfrom.GetId()); return; } int64_t nTime; CService addrMe; uint64_t nNonce = 1; ServiceFlags nServices; int nVersion; std::string cleanSubVer; int starting_height = -1; bool fRelay = true; vRecv >> nVersion >> Using>(nServices) >> nTime; if (nTime < 0) { nTime = 0; } vRecv.ignore(8); // Ignore the addrMe service bits sent by the peer vRecv >> CNetAddr::V1(addrMe); if (!pfrom.IsInboundConn()) { // Overwrites potentially existing services. In contrast to this, // unvalidated services received via gossip relay in ADDR/ADDRV2 // messages are only ever added but cannot replace existing ones. m_addrman.SetServices(pfrom.addr, nServices); } if (pfrom.ExpectServicesFromConn() && !HasAllDesirableServiceFlags(nServices)) { LogPrint(BCLog::NET, "peer=%d does not offer the expected services (%08x offered, %08x expected); disconnecting\n", pfrom.GetId(), nServices, GetDesirableServiceFlags(nServices)); pfrom.fDisconnect = true; return; } if (nVersion < MIN_PEER_PROTO_VERSION) { // disconnect from peers older than this proto version LogPrint(BCLog::NET, "peer=%d using obsolete version %i; disconnecting\n", pfrom.GetId(), nVersion); pfrom.fDisconnect = true; return; } if (!vRecv.empty()) { // The version message includes information about the sending node which we don't use: // - 8 bytes (service bits) // - 16 bytes (ipv6 address) // - 2 bytes (port) vRecv.ignore(26); vRecv >> nNonce; } if (!vRecv.empty()) { std::string strSubVer; vRecv >> LIMITED_STRING(strSubVer, MAX_SUBVERSION_LENGTH); cleanSubVer = SanitizeString(strSubVer); } if (!vRecv.empty()) { vRecv >> starting_height; } if (!vRecv.empty()) vRecv >> fRelay; // Disconnect if we connected to ourself if (pfrom.IsInboundConn() && !m_connman.CheckIncomingNonce(nNonce)) { LogPrintf("connected to self at %s, disconnecting\n", pfrom.addr.ToStringAddrPort()); pfrom.fDisconnect = true; return; } if (pfrom.IsInboundConn() && addrMe.IsRoutable()) { SeenLocal(addrMe); } // Inbound peers send us their version message when they connect. // We send our version message in response. if (pfrom.IsInboundConn()) { PushNodeVersion(pfrom, *peer); } // Change version const int greatest_common_version = std::min(nVersion, PROTOCOL_VERSION); pfrom.SetCommonVersion(greatest_common_version); pfrom.nVersion = nVersion; if (greatest_common_version >= WTXID_RELAY_VERSION) { MakeAndPushMessage(pfrom, NetMsgType::WTXIDRELAY); } // Signal ADDRv2 support (BIP155). if (greatest_common_version >= 70016) { // BIP155 defines addrv2 and sendaddrv2 for all protocol versions, but some // implementations reject messages they don't know. As a courtesy, don't send // it to nodes with a version before 70016, as no software is known to support // BIP155 that doesn't announce at least that protocol version number. MakeAndPushMessage(pfrom, NetMsgType::SENDADDRV2); } pfrom.m_has_all_wanted_services = HasAllDesirableServiceFlags(nServices); peer->m_their_services = nServices; pfrom.SetAddrLocal(addrMe); { LOCK(pfrom.m_subver_mutex); pfrom.cleanSubVer = cleanSubVer; } peer->m_starting_height = starting_height; // Only initialize the Peer::TxRelay m_relay_txs data structure if: // - this isn't an outbound block-relay-only connection, and // - this isn't an outbound feeler connection, and // - fRelay=true (the peer wishes to receive transaction announcements) // or we're offering NODE_BLOOM to this peer. NODE_BLOOM means that // the peer may turn on transaction relay later. if (!pfrom.IsBlockOnlyConn() && !pfrom.IsFeelerConn() && (fRelay || (peer->m_our_services & NODE_BLOOM))) { auto* const tx_relay = peer->SetTxRelay(); { LOCK(tx_relay->m_bloom_filter_mutex); tx_relay->m_relay_txs = fRelay; // set to true after we get the first filter* message } if (fRelay) pfrom.m_relays_txs = true; } if (greatest_common_version >= WTXID_RELAY_VERSION && m_txreconciliation) { // Per BIP-330, we announce txreconciliation support if: // - protocol version per the peer's VERSION message supports WTXID_RELAY; // - transaction relay is supported per the peer's VERSION message // - this is not a block-relay-only connection and not a feeler // - this is not an addr fetch connection; // - we are not in -blocksonly mode. const auto* tx_relay = peer->GetTxRelay(); if (tx_relay && WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs) && !pfrom.IsAddrFetchConn() && !m_opts.ignore_incoming_txs) { const uint64_t recon_salt = m_txreconciliation->PreRegisterPeer(pfrom.GetId()); MakeAndPushMessage(pfrom, NetMsgType::SENDTXRCNCL, TXRECONCILIATION_VERSION, recon_salt); } } MakeAndPushMessage(pfrom, NetMsgType::VERACK); // Potentially mark this peer as a preferred download peer. { LOCK(cs_main); CNodeState* state = State(pfrom.GetId()); state->fPreferredDownload = (!pfrom.IsInboundConn() || pfrom.HasPermission(NetPermissionFlags::NoBan)) && !pfrom.IsAddrFetchConn() && CanServeBlocks(*peer); m_num_preferred_download_peers += state->fPreferredDownload; } // Attempt to initialize address relay for outbound peers and use result // to decide whether to send GETADDR, so that we don't send it to // inbound or outbound block-relay-only peers. bool send_getaddr{false}; if (!pfrom.IsInboundConn()) { send_getaddr = SetupAddressRelay(pfrom, *peer); } if (send_getaddr) { // Do a one-time address fetch to help populate/update our addrman. // If we're starting up for the first time, our addrman may be pretty // empty, so this mechanism is important to help us connect to the network. // We skip this for block-relay-only peers. We want to avoid // potentially leaking addr information and we do not want to // indicate to the peer that we will participate in addr relay. MakeAndPushMessage(pfrom, NetMsgType::GETADDR); peer->m_getaddr_sent = true; // When requesting a getaddr, accept an additional MAX_ADDR_TO_SEND addresses in response // (bypassing the MAX_ADDR_PROCESSING_TOKEN_BUCKET limit). peer->m_addr_token_bucket += MAX_ADDR_TO_SEND; } if (!pfrom.IsInboundConn()) { // For non-inbound connections, we update the addrman to record // connection success so that addrman will have an up-to-date // notion of which peers are online and available. // // While we strive to not leak information about block-relay-only // connections via the addrman, not moving an address to the tried // table is also potentially detrimental because new-table entries // are subject to eviction in the event of addrman collisions. We // mitigate the information-leak by never calling // AddrMan::Connected() on block-relay-only peers; see // FinalizeNode(). // // This moves an address from New to Tried table in Addrman, // resolves tried-table collisions, etc. m_addrman.Good(pfrom.addr); } std::string remoteAddr; if (fLogIPs) remoteAddr = ", peeraddr=" + pfrom.addr.ToStringAddrPort(); const auto mapped_as{m_connman.GetMappedAS(pfrom.addr)}; LogPrint(BCLog::NET, "receive version message: %s: version %d, blocks=%d, us=%s, txrelay=%d, peer=%d%s%s\n", cleanSubVer, pfrom.nVersion, peer->m_starting_height, addrMe.ToStringAddrPort(), fRelay, pfrom.GetId(), remoteAddr, (mapped_as ? strprintf(", mapped_as=%d", mapped_as) : "")); peer->m_time_offset = NodeSeconds{std::chrono::seconds{nTime}} - Now(); if (!pfrom.IsInboundConn()) { // Don't use timedata samples from inbound peers to make it // harder for others to create false warnings about our clock being out of sync. m_outbound_time_offsets.Add(peer->m_time_offset); m_outbound_time_offsets.WarnIfOutOfSync(); } // If the peer is old enough to have the old alert system, send it the final alert. if (greatest_common_version <= 70012) { const auto finalAlert{ParseHex("60010000000000000000000000ffffff7f00000000ffffff7ffeffff7f01ffffff7f00000000ffffff7f00ffffff7f002f555247454e543a20416c657274206b657920636f6d70726f6d697365642c2075706772616465207265717569726564004630440220653febd6410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3abd5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fecaae66ecf689bf71b50")}; MakeAndPushMessage(pfrom, "alert", Span{finalAlert}); } // Feeler connections exist only to verify if address is online. if (pfrom.IsFeelerConn()) { LogPrint(BCLog::NET, "feeler connection completed peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (pfrom.nVersion == 0) { // Must have a version message before anything else LogPrint(BCLog::NET, "non-version message before version handshake. Message \"%s\" from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } if (msg_type == NetMsgType::VERACK) { if (pfrom.fSuccessfullyConnected) { LogPrint(BCLog::NET, "ignoring redundant verack message from peer=%d\n", pfrom.GetId()); return; } // Log successful connections unconditionally for outbound, but not for inbound as those // can be triggered by an attacker at high rate. if (!pfrom.IsInboundConn() || LogAcceptCategory(BCLog::NET, BCLog::Level::Debug)) { const auto mapped_as{m_connman.GetMappedAS(pfrom.addr)}; LogPrintf("New %s %s peer connected: version: %d, blocks=%d, peer=%d%s%s\n", pfrom.ConnectionTypeAsString(), TransportTypeAsString(pfrom.m_transport->GetInfo().transport_type), pfrom.nVersion.load(), peer->m_starting_height, pfrom.GetId(), (fLogIPs ? strprintf(", peeraddr=%s", pfrom.addr.ToStringAddrPort()) : ""), (mapped_as ? strprintf(", mapped_as=%d", mapped_as) : "")); } if (pfrom.GetCommonVersion() >= SHORT_IDS_BLOCKS_VERSION) { // Tell our peer we are willing to provide version 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 MakeAndPushMessage(pfrom, NetMsgType::SENDCMPCT, /*high_bandwidth=*/false, /*version=*/CMPCTBLOCKS_VERSION); } if (m_txreconciliation) { if (!peer->m_wtxid_relay || !m_txreconciliation->IsPeerRegistered(pfrom.GetId())) { // We could have optimistically pre-registered/registered the peer. In that case, // we should forget about the reconciliation state here if this wasn't followed // by WTXIDRELAY (since WTXIDRELAY can't be announced later). m_txreconciliation->ForgetPeer(pfrom.GetId()); } } if (auto tx_relay = peer->GetTxRelay()) { // `TxRelay::m_tx_inventory_to_send` must be empty before the // version handshake is completed as // `TxRelay::m_next_inv_send_time` is first initialised in // `SendMessages` after the verack is received. Any transactions // received during the version handshake would otherwise // immediately be advertised without random delay, potentially // leaking the time of arrival to a spy. Assume(WITH_LOCK( tx_relay->m_tx_inventory_mutex, return tx_relay->m_tx_inventory_to_send.empty() && tx_relay->m_next_inv_send_time == 0s)); } pfrom.fSuccessfullyConnected = true; return; } if (msg_type == NetMsgType::SENDHEADERS) { peer->m_prefers_headers = true; return; } if (msg_type == NetMsgType::SENDCMPCT) { bool sendcmpct_hb{false}; uint64_t sendcmpct_version{0}; vRecv >> sendcmpct_hb >> sendcmpct_version; // Only support compact block relay with witnesses if (sendcmpct_version != CMPCTBLOCKS_VERSION) return; LOCK(cs_main); CNodeState* nodestate = State(pfrom.GetId()); nodestate->m_provides_cmpctblocks = true; nodestate->m_requested_hb_cmpctblocks = sendcmpct_hb; // save whether peer selects us as BIP152 high-bandwidth peer // (receiving sendcmpct(1) signals high-bandwidth, sendcmpct(0) low-bandwidth) pfrom.m_bip152_highbandwidth_from = sendcmpct_hb; return; } // BIP339 defines feature negotiation of wtxidrelay, which must happen between // VERSION and VERACK to avoid relay problems from switching after a connection is up. if (msg_type == NetMsgType::WTXIDRELAY) { if (pfrom.fSuccessfullyConnected) { // Disconnect peers that send a wtxidrelay message after VERACK. LogPrint(BCLog::NET, "wtxidrelay received after verack from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } if (pfrom.GetCommonVersion() >= WTXID_RELAY_VERSION) { if (!peer->m_wtxid_relay) { peer->m_wtxid_relay = true; m_wtxid_relay_peers++; } else { LogPrint(BCLog::NET, "ignoring duplicate wtxidrelay from peer=%d\n", pfrom.GetId()); } } else { LogPrint(BCLog::NET, "ignoring wtxidrelay due to old common version=%d from peer=%d\n", pfrom.GetCommonVersion(), pfrom.GetId()); } return; } // BIP155 defines feature negotiation of addrv2 and sendaddrv2, which must happen // between VERSION and VERACK. if (msg_type == NetMsgType::SENDADDRV2) { if (pfrom.fSuccessfullyConnected) { // Disconnect peers that send a SENDADDRV2 message after VERACK. LogPrint(BCLog::NET, "sendaddrv2 received after verack from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } peer->m_wants_addrv2 = true; return; } // Received from a peer demonstrating readiness to announce transactions via reconciliations. // This feature negotiation must happen between VERSION and VERACK to avoid relay problems // from switching announcement protocols after the connection is up. if (msg_type == NetMsgType::SENDTXRCNCL) { if (!m_txreconciliation) { LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl from peer=%d ignored, as our node does not have txreconciliation enabled\n", pfrom.GetId()); return; } if (pfrom.fSuccessfullyConnected) { LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received after verack from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } // Peer must not offer us reconciliations if we specified no tx relay support in VERSION. if (RejectIncomingTxs(pfrom)) { LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received from peer=%d to which we indicated no tx relay; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } // Peer must not offer us reconciliations if they specified no tx relay support in VERSION. // This flag might also be false in other cases, but the RejectIncomingTxs check above // eliminates them, so that this flag fully represents what we are looking for. const auto* tx_relay = peer->GetTxRelay(); if (!tx_relay || !WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs)) { LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "sendtxrcncl received from peer=%d which indicated no tx relay to us; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } uint32_t peer_txreconcl_version; uint64_t remote_salt; vRecv >> peer_txreconcl_version >> remote_salt; const ReconciliationRegisterResult result = m_txreconciliation->RegisterPeer(pfrom.GetId(), pfrom.IsInboundConn(), peer_txreconcl_version, remote_salt); switch (result) { case ReconciliationRegisterResult::NOT_FOUND: LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "Ignore unexpected txreconciliation signal from peer=%d\n", pfrom.GetId()); break; case ReconciliationRegisterResult::SUCCESS: break; case ReconciliationRegisterResult::ALREADY_REGISTERED: LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "txreconciliation protocol violation from peer=%d (sendtxrcncl received from already registered peer); disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; case ReconciliationRegisterResult::PROTOCOL_VIOLATION: LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "txreconciliation protocol violation from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } return; } if (!pfrom.fSuccessfullyConnected) { LogPrint(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } if (msg_type == NetMsgType::ADDR || msg_type == NetMsgType::ADDRV2) { const auto ser_params{ msg_type == NetMsgType::ADDRV2 ? // Set V2 param so that the CNetAddr and CAddress // unserialize methods know that an address in v2 format is coming. CAddress::V2_NETWORK : CAddress::V1_NETWORK, }; std::vector vAddr; vRecv >> ser_params(vAddr); if (!SetupAddressRelay(pfrom, *peer)) { LogPrint(BCLog::NET, "ignoring %s message from %s peer=%d\n", msg_type, pfrom.ConnectionTypeAsString(), pfrom.GetId()); return; } if (vAddr.size() > MAX_ADDR_TO_SEND) { Misbehaving(*peer, 20, strprintf("%s message size = %u", msg_type, vAddr.size())); return; } // Store the new addresses std::vector vAddrOk; const auto current_a_time{Now()}; // Update/increment addr rate limiting bucket. const auto current_time{GetTime()}; if (peer->m_addr_token_bucket < MAX_ADDR_PROCESSING_TOKEN_BUCKET) { // Don't increment bucket if it's already full const auto time_diff = std::max(current_time - peer->m_addr_token_timestamp, 0us); const double increment = Ticks(time_diff) * MAX_ADDR_RATE_PER_SECOND; peer->m_addr_token_bucket = std::min(peer->m_addr_token_bucket + increment, MAX_ADDR_PROCESSING_TOKEN_BUCKET); } peer->m_addr_token_timestamp = current_time; const bool rate_limited = !pfrom.HasPermission(NetPermissionFlags::Addr); uint64_t num_proc = 0; uint64_t num_rate_limit = 0; Shuffle(vAddr.begin(), vAddr.end(), m_rng); for (CAddress& addr : vAddr) { if (interruptMsgProc) return; // Apply rate limiting. if (peer->m_addr_token_bucket < 1.0) { if (rate_limited) { ++num_rate_limit; continue; } } else { peer->m_addr_token_bucket -= 1.0; } // 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 <= NodeSeconds{100000000s} || addr.nTime > current_a_time + 10min) { addr.nTime = current_a_time - 5 * 24h; } AddAddressKnown(*peer, addr); if (m_banman && (m_banman->IsDiscouraged(addr) || m_banman->IsBanned(addr))) { // Do not process banned/discouraged addresses beyond remembering we received them continue; } ++num_proc; const bool reachable{g_reachable_nets.Contains(addr)}; if (addr.nTime > current_a_time - 10min && !peer->m_getaddr_sent && vAddr.size() <= 10 && addr.IsRoutable()) { // Relay to a limited number of other nodes RelayAddress(pfrom.GetId(), addr, reachable); } // Do not store addresses outside our network if (reachable) { vAddrOk.push_back(addr); } } peer->m_addr_processed += num_proc; peer->m_addr_rate_limited += num_rate_limit; LogPrint(BCLog::NET, "Received addr: %u addresses (%u processed, %u rate-limited) from peer=%d\n", vAddr.size(), num_proc, num_rate_limit, pfrom.GetId()); m_addrman.Add(vAddrOk, pfrom.addr, 2h); if (vAddr.size() < 1000) peer->m_getaddr_sent = false; // AddrFetch: Require multiple addresses to avoid disconnecting on self-announcements if (pfrom.IsAddrFetchConn() && vAddr.size() > 1) { LogPrint(BCLog::NET, "addrfetch connection completed peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (msg_type == NetMsgType::INV) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { Misbehaving(*peer, 20, strprintf("inv message size = %u", vInv.size())); return; } const bool reject_tx_invs{RejectIncomingTxs(pfrom)}; LOCK(cs_main); const auto current_time{GetTime()}; uint256* best_block{nullptr}; for (CInv& inv : vInv) { if (interruptMsgProc) return; // Ignore INVs that don't match wtxidrelay setting. // Note that orphan parent fetching always uses MSG_TX GETDATAs regardless of the wtxidrelay setting. // This is fine as no INV messages are involved in that process. if (peer->m_wtxid_relay) { if (inv.IsMsgTx()) continue; } else { if (inv.IsMsgWtx()) continue; } if (inv.IsMsgBlk()) { const bool fAlreadyHave = AlreadyHaveBlock(inv.hash); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId()); UpdateBlockAvailability(pfrom.GetId(), inv.hash); if (!fAlreadyHave && !m_chainman.m_blockman.LoadingBlocks() && !IsBlockRequested(inv.hash)) { // Headers-first is the primary method of announcement on // the network. If a node fell back to sending blocks by // inv, it may be for a re-org, or because we haven't // completed initial headers sync. The final block hash // provided should be the highest, so send a getheaders and // then fetch the blocks we need to catch up. best_block = &inv.hash; } } else if (inv.IsGenTxMsg()) { if (reject_tx_invs) { LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol, disconnecting peer=%d\n", inv.hash.ToString(), pfrom.GetId()); pfrom.fDisconnect = true; return; } const GenTxid gtxid = ToGenTxid(inv); const bool fAlreadyHave = AlreadyHaveTx(gtxid, /*include_reconsiderable=*/true); LogPrint(BCLog::NET, "got inv: %s %s peer=%d\n", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId()); AddKnownTx(*peer, inv.hash); if (!fAlreadyHave && !m_chainman.IsInitialBlockDownload()) { AddTxAnnouncement(pfrom, gtxid, current_time); } } else { LogPrint(BCLog::NET, "Unknown inv type \"%s\" received from peer=%d\n", inv.ToString(), pfrom.GetId()); } } if (best_block != nullptr) { // If we haven't started initial headers-sync with this peer, then // consider sending a getheaders now. On initial startup, there's a // reliability vs bandwidth tradeoff, where we are only trying to do // initial headers sync with one peer at a time, with a long // timeout (at which point, if the sync hasn't completed, we will // disconnect the peer and then choose another). In the meantime, // as new blocks are found, we are willing to add one new peer per // block to sync with as well, to sync quicker in the case where // our initial peer is unresponsive (but less bandwidth than we'd // use if we turned on sync with all peers). CNodeState& state{*Assert(State(pfrom.GetId()))}; if (state.fSyncStarted || (!peer->m_inv_triggered_getheaders_before_sync && *best_block != m_last_block_inv_triggering_headers_sync)) { if (MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), *peer)) { LogPrint(BCLog::NET, "getheaders (%d) %s to peer=%d\n", m_chainman.m_best_header->nHeight, best_block->ToString(), pfrom.GetId()); } if (!state.fSyncStarted) { peer->m_inv_triggered_getheaders_before_sync = true; // Update the last block hash that triggered a new headers // sync, so that we don't turn on headers sync with more // than 1 new peer every new block. m_last_block_inv_triggering_headers_sync = *best_block; } } } return; } if (msg_type == NetMsgType::GETDATA) { std::vector vInv; vRecv >> vInv; if (vInv.size() > MAX_INV_SZ) { Misbehaving(*peer, 20, strprintf("getdata message size = %u", vInv.size())); return; } LogPrint(BCLog::NET, "received getdata (%u invsz) peer=%d\n", vInv.size(), pfrom.GetId()); if (vInv.size() > 0) { LogPrint(BCLog::NET, "received getdata for: %s peer=%d\n", vInv[0].ToString(), pfrom.GetId()); } { LOCK(peer->m_getdata_requests_mutex); peer->m_getdata_requests.insert(peer->m_getdata_requests.end(), vInv.begin(), vInv.end()); ProcessGetData(pfrom, *peer, interruptMsgProc); } return; } if (msg_type == NetMsgType::GETBLOCKS) { CBlockLocator locator; uint256 hashStop; vRecv >> locator >> hashStop; if (locator.vHave.size() > MAX_LOCATOR_SZ) { LogPrint(BCLog::NET, "getblocks locator size %lld > %d, disconnect peer=%d\n", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId()); pfrom.fDisconnect = true; return; } // We might have announced the currently-being-connected tip using a // compact block, which resulted in the peer sending a getblocks // request, which we would otherwise respond to without the new block. // To avoid this situation we simply verify that we are on our best // known chain now. This is super overkill, but we handle it better // for getheaders requests, and there are no known nodes which support // compact blocks but still use getblocks to request blocks. { std::shared_ptr a_recent_block; { LOCK(m_most_recent_block_mutex); a_recent_block = m_most_recent_block; } BlockValidationState state; if (!m_chainman.ActiveChainstate().ActivateBestChain(state, a_recent_block)) { LogPrint(BCLog::NET, "failed to activate chain (%s)\n", state.ToString()); } } LOCK(cs_main); // Find the last block the caller has in the main chain const CBlockIndex* pindex = m_chainman.ActiveChainstate().FindForkInGlobalIndex(locator); // Send the rest of the chain if (pindex) pindex = m_chainman.ActiveChain().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 = m_chainman.ActiveChain().Next(pindex)) { if (pindex->GetBlockHash() == hashStop) { LogPrint(BCLog::NET, " getblocks stopping at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); break; } // If pruning, don't inv blocks unless we have on disk and are likely to still have // for some reasonable time window (1 hour) that block relay might require. const int nPrunedBlocksLikelyToHave = MIN_BLOCKS_TO_KEEP - 3600 / m_chainparams.GetConsensus().nPowTargetSpacing; if (m_chainman.m_blockman.IsPruneMode() && (!(pindex->nStatus & BLOCK_HAVE_DATA) || pindex->nHeight <= m_chainman.ActiveChain().Tip()->nHeight - nPrunedBlocksLikelyToHave)) { LogPrint(BCLog::NET, " getblocks stopping, pruned or too old block at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); break; } WITH_LOCK(peer->m_block_inv_mutex, peer->m_blocks_for_inv_relay.push_back(pindex->GetBlockHash())); if (--nLimit <= 0) { // When this block is requested, we'll send an inv that'll // trigger the peer to getblocks the next batch of inventory. LogPrint(BCLog::NET, " getblocks stopping at limit %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString()); WITH_LOCK(peer->m_block_inv_mutex, {peer->m_continuation_block = pindex->GetBlockHash();}); break; } } return; } if (msg_type == NetMsgType::GETBLOCKTXN) { BlockTransactionsRequest req; vRecv >> req; std::shared_ptr recent_block; { LOCK(m_most_recent_block_mutex); if (m_most_recent_block_hash == req.blockhash) recent_block = m_most_recent_block; // Unlock m_most_recent_block_mutex to avoid cs_main lock inversion } if (recent_block) { SendBlockTransactions(pfrom, *peer, *recent_block, req); return; } { LOCK(cs_main); const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(req.blockhash); if (!pindex || !(pindex->nStatus & BLOCK_HAVE_DATA)) { LogPrint(BCLog::NET, "Peer %d sent us a getblocktxn for a block we don't have\n", pfrom.GetId()); return; } if (pindex->nHeight >= m_chainman.ActiveChain().Height() - MAX_BLOCKTXN_DEPTH) { CBlock block; const bool ret{m_chainman.m_blockman.ReadBlockFromDisk(block, *pindex)}; assert(ret); SendBlockTransactions(pfrom, *peer, block, req); return; } } // If an older block is requested (should never happen in practice, // but can happen in tests) send a block response instead of a // blocktxn response. Sending a full block response instead of a // small blocktxn response is preferable in the case where a peer // might maliciously send lots of getblocktxn requests to trigger // expensive disk reads, because it will require the peer to // actually receive all the data read from disk over the network. LogPrint(BCLog::NET, "Peer %d sent us a getblocktxn for a block > %i deep\n", pfrom.GetId(), MAX_BLOCKTXN_DEPTH); CInv inv{MSG_WITNESS_BLOCK, req.blockhash}; WITH_LOCK(peer->m_getdata_requests_mutex, peer->m_getdata_requests.push_back(inv)); // The message processing loop will go around again (without pausing) and we'll respond then return; } if (msg_type == NetMsgType::GETHEADERS) { CBlockLocator locator; uint256 hashStop; vRecv >> locator >> hashStop; if (locator.vHave.size() > MAX_LOCATOR_SZ) { LogPrint(BCLog::NET, "getheaders locator size %lld > %d, disconnect peer=%d\n", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId()); pfrom.fDisconnect = true; return; } if (m_chainman.m_blockman.LoadingBlocks()) { LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d while importing/reindexing\n", pfrom.GetId()); return; } LOCK(cs_main); // Note that if we were to be on a chain that forks from the checkpointed // chain, then serving those headers to a peer that has seen the // checkpointed chain would cause that peer to disconnect us. Requiring // that our chainwork exceed the minimum chain work is a protection against // being fed a bogus chain when we started up for the first time and // getting partitioned off the honest network for serving that chain to // others. if (m_chainman.ActiveTip() == nullptr || (m_chainman.ActiveTip()->nChainWork < m_chainman.MinimumChainWork() && !pfrom.HasPermission(NetPermissionFlags::Download))) { LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because active chain has too little work; sending empty response\n", pfrom.GetId()); // Just respond with an empty headers message, to tell the peer to // go away but not treat us as unresponsive. MakeAndPushMessage(pfrom, NetMsgType::HEADERS, std::vector()); return; } CNodeState *nodestate = State(pfrom.GetId()); const CBlockIndex* pindex = nullptr; if (locator.IsNull()) { // If locator is null, return the hashStop block pindex = m_chainman.m_blockman.LookupBlockIndex(hashStop); if (!pindex) { return; } if (!BlockRequestAllowed(pindex)) { LogPrint(BCLog::NET, "%s: ignoring request from peer=%i for old block header that isn't in the main chain\n", __func__, pfrom.GetId()); return; } } else { // Find the last block the caller has in the main chain pindex = m_chainman.ActiveChainstate().FindForkInGlobalIndex(locator); if (pindex) pindex = m_chainman.ActiveChain().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 = m_chainman.ActiveChain().Next(pindex)) { vHeaders.emplace_back(pindex->GetBlockHeader()); if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop) break; } // pindex can be nullptr either if we sent m_chainman.ActiveChain().Tip() OR // if our peer has m_chainman.ActiveChain().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 : m_chainman.ActiveChain().Tip(); MakeAndPushMessage(pfrom, NetMsgType::HEADERS, TX_WITH_WITNESS(vHeaders)); return; } if (msg_type == NetMsgType::TX) { if (RejectIncomingTxs(pfrom)) { LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } // Stop processing the transaction early if we are still in IBD since we don't // have enough information to validate it yet. Sending unsolicited transactions // is not considered a protocol violation, so don't punish the peer. if (m_chainman.IsInitialBlockDownload()) return; CTransactionRef ptx; vRecv >> TX_WITH_WITNESS(ptx); const CTransaction& tx = *ptx; const uint256& txid = ptx->GetHash(); const uint256& wtxid = ptx->GetWitnessHash(); const uint256& hash = peer->m_wtxid_relay ? wtxid : txid; AddKnownTx(*peer, hash); LOCK(cs_main); m_txrequest.ReceivedResponse(pfrom.GetId(), txid); if (tx.HasWitness()) m_txrequest.ReceivedResponse(pfrom.GetId(), wtxid); // We do the AlreadyHaveTx() check using wtxid, rather than txid - in the // absence of witness malleation, this is strictly better, because the // recent rejects filter may contain the wtxid but rarely contains // the txid of a segwit transaction that has been rejected. // In the presence of witness malleation, it's possible that by only // doing the check with wtxid, we could overlook a transaction which // was confirmed with a different witness, or exists in our mempool // with a different witness, but this has limited downside: // mempool validation does its own lookup of whether we have the txid // already; and an adversary can already relay us old transactions // (older than our recency filter) if trying to DoS us, without any need // for witness malleation. if (AlreadyHaveTx(GenTxid::Wtxid(wtxid), /*include_reconsiderable=*/true)) { if (pfrom.HasPermission(NetPermissionFlags::ForceRelay)) { // Always relay transactions received from peers with forcerelay // permission, even if they were already in the mempool, allowing // the node to function as a gateway for nodes hidden behind it. if (!m_mempool.exists(GenTxid::Txid(tx.GetHash()))) { LogPrintf("Not relaying non-mempool transaction %s (wtxid=%s) from forcerelay peer=%d\n", tx.GetHash().ToString(), tx.GetWitnessHash().ToString(), pfrom.GetId()); } else { LogPrintf("Force relaying tx %s (wtxid=%s) from peer=%d\n", tx.GetHash().ToString(), tx.GetWitnessHash().ToString(), pfrom.GetId()); RelayTransaction(tx.GetHash(), tx.GetWitnessHash()); } } if (m_recent_rejects_reconsiderable.contains(wtxid)) { // When a transaction is already in m_recent_rejects_reconsiderable, we shouldn't submit // it by itself again. However, look for a matching child in the orphanage, as it is // possible that they succeed as a package. LogPrint(BCLog::TXPACKAGES, "found tx %s (wtxid=%s) in reconsiderable rejects, looking for child in orphanage\n", txid.ToString(), wtxid.ToString()); if (auto package_to_validate{Find1P1CPackage(ptx, pfrom.GetId())}) { const auto package_result{ProcessNewPackage(m_chainman.ActiveChainstate(), m_mempool, package_to_validate->m_txns, /*test_accept=*/false, /*client_maxfeerate=*/std::nullopt)}; LogDebug(BCLog::TXPACKAGES, "package evaluation for %s: %s\n", package_to_validate->ToString(), package_result.m_state.IsValid() ? "package accepted" : "package rejected"); ProcessPackageResult(package_to_validate->m_txns, package_result, package_to_validate->m_senders); } } // If a tx is detected by m_recent_rejects it is ignored. Because we haven't // submitted the tx to our mempool, 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 m_recent_rejects showing false positives. In // other words, we shouldn't penalize a peer if we aren't *sure* they // submitted a DoSy tx. // // Note that m_recent_rejects 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 m_recent_rejects has caught, // regardless of false positives. return; } const MempoolAcceptResult result = m_chainman.ProcessTransaction(ptx); const TxValidationState& state = result.m_state; if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) { Assume(result.m_replaced_transactions.has_value()); std::list empty_replacement_list; ProcessValidTx(pfrom.GetId(), ptx, result.m_replaced_transactions.value_or(empty_replacement_list)); pfrom.m_last_tx_time = GetTime(); } else if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) { bool fRejectedParents = false; // It may be the case that the orphans parents have all been rejected // Deduplicate parent txids, so that we don't have to loop over // the same parent txid more than once down below. std::vector unique_parents; unique_parents.reserve(tx.vin.size()); for (const CTxIn& txin : tx.vin) { // We start with all parents, and then remove duplicates below. unique_parents.push_back(txin.prevout.hash); } std::sort(unique_parents.begin(), unique_parents.end()); unique_parents.erase(std::unique(unique_parents.begin(), unique_parents.end()), unique_parents.end()); // Distinguish between parents in m_recent_rejects and m_recent_rejects_reconsiderable. // We can tolerate having up to 1 parent in m_recent_rejects_reconsiderable since we // submit 1p1c packages. However, fail immediately if any are in m_recent_rejects. std::optional rejected_parent_reconsiderable; for (const uint256& parent_txid : unique_parents) { if (m_recent_rejects.contains(parent_txid)) { fRejectedParents = true; break; } else if (m_recent_rejects_reconsiderable.contains(parent_txid) && !m_mempool.exists(GenTxid::Txid(parent_txid))) { // More than 1 parent in m_recent_rejects_reconsiderable: 1p1c will not be // sufficient to accept this package, so just give up here. if (rejected_parent_reconsiderable.has_value()) { fRejectedParents = true; break; } rejected_parent_reconsiderable = parent_txid; } } if (!fRejectedParents) { const auto current_time{GetTime()}; for (const uint256& parent_txid : unique_parents) { // Here, we only have the txid (and not wtxid) of the // inputs, so we only request in txid mode, even for // wtxidrelay peers. // Eventually we should replace this with an improved // protocol for getting all unconfirmed parents. const auto gtxid{GenTxid::Txid(parent_txid)}; AddKnownTx(*peer, parent_txid); // Exclude m_recent_rejects_reconsiderable: the missing parent may have been // previously rejected for being too low feerate. This orphan might CPFP it. if (!AlreadyHaveTx(gtxid, /*include_reconsiderable=*/false)) AddTxAnnouncement(pfrom, gtxid, current_time); } if (m_orphanage.AddTx(ptx, pfrom.GetId())) { AddToCompactExtraTransactions(ptx); } // Once added to the orphan pool, a tx is considered AlreadyHave, and we shouldn't request it anymore. m_txrequest.ForgetTxHash(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); // DoS prevention: do not allow m_orphanage to grow unbounded (see CVE-2012-3789) m_orphanage.LimitOrphans(m_opts.max_orphan_txs, m_rng); } else { LogPrint(BCLog::MEMPOOL, "not keeping orphan with rejected parents %s (wtxid=%s)\n", tx.GetHash().ToString(), tx.GetWitnessHash().ToString()); // We will continue to reject this tx since it has rejected // parents so avoid re-requesting it from other peers. // Here we add both the txid and the wtxid, as we know that // regardless of what witness is provided, we will not accept // this, so we don't need to allow for redownload of this txid // from any of our non-wtxidrelay peers. m_recent_rejects.insert(tx.GetHash().ToUint256()); m_recent_rejects.insert(tx.GetWitnessHash().ToUint256()); m_txrequest.ForgetTxHash(tx.GetHash()); m_txrequest.ForgetTxHash(tx.GetWitnessHash()); } } if (state.IsInvalid()) { ProcessInvalidTx(pfrom.GetId(), ptx, state, /*maybe_add_extra_compact_tx=*/true); } // When a transaction fails for TX_RECONSIDERABLE, look for a matching child in the // orphanage, as it is possible that they succeed as a package. if (state.GetResult() == TxValidationResult::TX_RECONSIDERABLE) { LogPrint(BCLog::TXPACKAGES, "tx %s (wtxid=%s) failed but reconsiderable, looking for child in orphanage\n", txid.ToString(), wtxid.ToString()); if (auto package_to_validate{Find1P1CPackage(ptx, pfrom.GetId())}) { const auto package_result{ProcessNewPackage(m_chainman.ActiveChainstate(), m_mempool, package_to_validate->m_txns, /*test_accept=*/false, /*client_maxfeerate=*/std::nullopt)}; LogDebug(BCLog::TXPACKAGES, "package evaluation for %s: %s\n", package_to_validate->ToString(), package_result.m_state.IsValid() ? "package accepted" : "package rejected"); ProcessPackageResult(package_to_validate->m_txns, package_result, package_to_validate->m_senders); } } return; } if (msg_type == NetMsgType::CMPCTBLOCK) { // Ignore cmpctblock received while importing if (m_chainman.m_blockman.LoadingBlocks()) { LogPrint(BCLog::NET, "Unexpected cmpctblock message received from peer %d\n", pfrom.GetId()); return; } CBlockHeaderAndShortTxIDs cmpctblock; vRecv >> cmpctblock; bool received_new_header = false; const auto blockhash = cmpctblock.header.GetHash(); { LOCK(cs_main); const CBlockIndex* prev_block = m_chainman.m_blockman.LookupBlockIndex(cmpctblock.header.hashPrevBlock); if (!prev_block) { // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers if (!m_chainman.IsInitialBlockDownload()) { MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), *peer); } return; } else if (prev_block->nChainWork + CalculateClaimedHeadersWork({cmpctblock.header}) < GetAntiDoSWorkThreshold()) { // If we get a low-work header in a compact block, we can ignore it. LogPrint(BCLog::NET, "Ignoring low-work compact block from peer %d\n", pfrom.GetId()); return; } if (!m_chainman.m_blockman.LookupBlockIndex(blockhash)) { received_new_header = true; } } const CBlockIndex *pindex = nullptr; BlockValidationState state; if (!m_chainman.ProcessNewBlockHeaders({cmpctblock.header}, /*min_pow_checked=*/true, state, &pindex)) { if (state.IsInvalid()) { MaybePunishNodeForBlock(pfrom.GetId(), state, /*via_compact_block=*/true, "invalid header via cmpctblock"); return; } } if (received_new_header) { LogInfo("Saw new cmpctblock header hash=%s peer=%d\n", blockhash.ToString(), pfrom.GetId()); } bool fProcessBLOCKTXN = false; // 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; { LOCK(cs_main); // 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 > m_chainman.ActiveChain().Tip()->nChainWork) { nodestate->m_last_block_announcement = GetTime(); } if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here return; auto range_flight = mapBlocksInFlight.equal_range(pindex->GetBlockHash()); size_t already_in_flight = std::distance(range_flight.first, range_flight.second); bool requested_block_from_this_peer{false}; // Multimap ensures ordering of outstanding requests. It's either empty or first in line. bool first_in_flight = already_in_flight == 0 || (range_flight.first->second.first == pfrom.GetId()); while (range_flight.first != range_flight.second) { if (range_flight.first->second.first == pfrom.GetId()) { requested_block_from_this_peer = true; break; } range_flight.first++; } if (pindex->nChainWork <= m_chainman.ActiveChain().Tip()->nChainWork || // We know something better pindex->nTx != 0) { // We had this block at some point, but pruned it if (requested_block_from_this_peer) { // 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(*peer), blockhash); MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv); } return; } // If we're not close to tip yet, give up and let parallel block fetch work its magic if (!already_in_flight && !CanDirectFetch()) { return; } // We want to be a bit conservative just to be extra careful about DoS // possibilities in compact block processing... if (pindex->nHeight <= m_chainman.ActiveChain().Height() + 2) { if ((already_in_flight < MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK && nodestate->vBlocksInFlight.size() < MAX_BLOCKS_IN_TRANSIT_PER_PEER) || requested_block_from_this_peer) { std::list::iterator* queuedBlockIt = nullptr; if (!BlockRequested(pfrom.GetId(), *pindex, &queuedBlockIt)) { if (!(*queuedBlockIt)->partialBlock) (*queuedBlockIt)->partialBlock.reset(new PartiallyDownloadedBlock(&m_mempool)); else { // The block was already in flight using compact blocks from the same peer LogPrint(BCLog::NET, "Peer sent us compact block we were already syncing!\n"); return; } } PartiallyDownloadedBlock& partialBlock = *(*queuedBlockIt)->partialBlock; ReadStatus status = partialBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status == READ_STATUS_INVALID) { RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect Misbehaving(*peer, 100, "invalid compact block"); return; } else if (status == READ_STATUS_FAILED) { if (first_in_flight) { // Duplicate txindexes, the block is now in-flight, so just request it std::vector vInv(1); vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(*peer), blockhash); MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv); } else { // Give up for this peer and wait for other peer(s) RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId()); } return; } BlockTransactionsRequest req; for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) { if (!partialBlock.IsTxAvailable(i)) req.indexes.push_back(i); } if (req.indexes.empty()) { fProcessBLOCKTXN = true; } else if (first_in_flight) { // We will try to round-trip any compact blocks we get on failure, // as long as it's first... req.blockhash = pindex->GetBlockHash(); MakeAndPushMessage(pfrom, NetMsgType::GETBLOCKTXN, req); } else if (pfrom.m_bip152_highbandwidth_to && (!pfrom.IsInboundConn() || IsBlockRequestedFromOutbound(blockhash) || already_in_flight < MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK - 1)) { // ... or it's a hb relay peer and: // - peer is outbound, or // - we already have an outbound attempt in flight(so we'll take what we can get), or // - it's not the final parallel download slot (which we may reserve for first outbound) req.blockhash = pindex->GetBlockHash(); MakeAndPushMessage(pfrom, NetMsgType::GETBLOCKTXN, req); } else { // Give up for this peer and wait for other peer(s) RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId()); } } else { // This block is either already in flight from a different // peer, or this peer has too many blocks outstanding to // download from. // Optimistically try to reconstruct anyway since we might be // able to without any round trips. PartiallyDownloadedBlock tempBlock(&m_mempool); ReadStatus status = tempBlock.InitData(cmpctblock, vExtraTxnForCompact); if (status != READ_STATUS_OK) { // TODO: don't ignore failures return; } std::vector dummy; status = tempBlock.FillBlock(*pblock, dummy); if (status == READ_STATUS_OK) { fBlockReconstructed = true; } } } else { if (requested_block_from_this_peer) { // 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(*peer), blockhash); MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv); return; } else { // If this was an announce-cmpctblock, we want the same treatment as a header message fRevertToHeaderProcessing = true; } } } // cs_main if (fProcessBLOCKTXN) { BlockTransactions txn; txn.blockhash = blockhash; return ProcessCompactBlockTxns(pfrom, *peer, txn); } if (fRevertToHeaderProcessing) { // Headers received from HB compact block peers are permitted to be // relayed before full validation (see BIP 152), so we don't want to disconnect // the peer if the header turns out to be for an invalid block. // Note that if a peer tries to build on an invalid chain, that // will be detected and the peer will be disconnected/discouraged. return ProcessHeadersMessage(pfrom, *peer, {cmpctblock.header}, /*via_compact_block=*/true); } if (fBlockReconstructed) { // If we got here, we were able to optimistically reconstruct a // block that is in flight from some other peer. { LOCK(cs_main); mapBlockSource.emplace(pblock->GetHash(), std::make_pair(pfrom.GetId(), false)); } // Setting force_processing 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 the minimum chain work), and we ignore // compact blocks with less work than our tip, it is safe to treat // reconstructed compact blocks as having been requested. ProcessBlock(pfrom, pblock, /*force_processing=*/true, /*min_pow_checked=*/true); 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. RemoveBlockRequest(pblock->GetHash(), std::nullopt); } } return; } if (msg_type == NetMsgType::BLOCKTXN) { // Ignore blocktxn received while importing if (m_chainman.m_blockman.LoadingBlocks()) { LogPrint(BCLog::NET, "Unexpected blocktxn message received from peer %d\n", pfrom.GetId()); return; } BlockTransactions resp; vRecv >> resp; return ProcessCompactBlockTxns(pfrom, *peer, resp); } if (msg_type == NetMsgType::HEADERS) { // Ignore headers received while importing if (m_chainman.m_blockman.LoadingBlocks()) { LogPrint(BCLog::NET, "Unexpected headers message received from peer %d\n", pfrom.GetId()); return; } // Assume that this is in response to any outstanding getheaders // request we may have sent, and clear out the time of our last request peer->m_last_getheaders_timestamp = {}; std::vector headers; // Bypass the normal CBlock deserialization, as we don't want to risk deserializing 2000 full blocks. unsigned int nCount = ReadCompactSize(vRecv); if (nCount > MAX_HEADERS_RESULTS) { Misbehaving(*peer, 20, strprintf("headers message size = %u", nCount)); return; } headers.resize(nCount); for (unsigned int n = 0; n < nCount; n++) { vRecv >> headers[n]; ReadCompactSize(vRecv); // ignore tx count; assume it is 0. } ProcessHeadersMessage(pfrom, *peer, std::move(headers), /*via_compact_block=*/false); // Check if the headers presync progress needs to be reported to validation. // This needs to be done without holding the m_headers_presync_mutex lock. if (m_headers_presync_should_signal.exchange(false)) { HeadersPresyncStats stats; { LOCK(m_headers_presync_mutex); auto it = m_headers_presync_stats.find(m_headers_presync_bestpeer); if (it != m_headers_presync_stats.end()) stats = it->second; } if (stats.second) { m_chainman.ReportHeadersPresync(stats.first, stats.second->first, stats.second->second); } } return; } if (msg_type == NetMsgType::BLOCK) { // Ignore block received while importing if (m_chainman.m_blockman.LoadingBlocks()) { LogPrint(BCLog::NET, "Unexpected block message received from peer %d\n", pfrom.GetId()); return; } std::shared_ptr pblock = std::make_shared(); vRecv >> TX_WITH_WITNESS(*pblock); LogPrint(BCLog::NET, "received block %s peer=%d\n", pblock->GetHash().ToString(), pfrom.GetId()); const CBlockIndex* prev_block{WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.LookupBlockIndex(pblock->hashPrevBlock))}; // Check for possible mutation if it connects to something we know so we can check for DEPLOYMENT_SEGWIT being active if (prev_block && IsBlockMutated(/*block=*/*pblock, /*check_witness_root=*/DeploymentActiveAfter(prev_block, m_chainman, Consensus::DEPLOYMENT_SEGWIT))) { LogDebug(BCLog::NET, "Received mutated block from peer=%d\n", peer->m_id); Misbehaving(*peer, 100, "mutated block"); WITH_LOCK(cs_main, RemoveBlockRequest(pblock->GetHash(), peer->m_id)); return; } bool forceProcessing = false; const uint256 hash(pblock->GetHash()); bool min_pow_checked = false; { LOCK(cs_main); // Always process the block if we requested it, since we may // need it even when it's not a candidate for a new best tip. forceProcessing = IsBlockRequested(hash); RemoveBlockRequest(hash, pfrom.GetId()); // mapBlockSource is only used for punishing peers and setting // which peers send us compact blocks, so the race between here and // cs_main in ProcessNewBlock is fine. mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true)); // Check claimed work on this block against our anti-dos thresholds. if (prev_block && prev_block->nChainWork + CalculateClaimedHeadersWork({pblock->GetBlockHeader()}) >= GetAntiDoSWorkThreshold()) { min_pow_checked = true; } } ProcessBlock(pfrom, pblock, forceProcessing, min_pow_checked); return; } if (msg_type == NetMsgType::GETADDR) { // This asymmetric behavior for inbound and outbound connections was introduced // to prevent a fingerprinting attack: an attacker can send specific fake addresses // to users' AddrMan and later request them by sending getaddr messages. // Making nodes which are behind NAT and can only make outgoing connections ignore // the getaddr message mitigates the attack. if (!pfrom.IsInboundConn()) { LogPrint(BCLog::NET, "Ignoring \"getaddr\" from %s connection. peer=%d\n", pfrom.ConnectionTypeAsString(), pfrom.GetId()); return; } // Since this must be an inbound connection, SetupAddressRelay will // never fail. Assume(SetupAddressRelay(pfrom, *peer)); // Only send one GetAddr response per connection to reduce resource waste // and discourage addr stamping of INV announcements. if (peer->m_getaddr_recvd) { LogPrint(BCLog::NET, "Ignoring repeated \"getaddr\". peer=%d\n", pfrom.GetId()); return; } peer->m_getaddr_recvd = true; peer->m_addrs_to_send.clear(); std::vector vAddr; if (pfrom.HasPermission(NetPermissionFlags::Addr)) { vAddr = m_connman.GetAddresses(MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND, /*network=*/std::nullopt); } else { vAddr = m_connman.GetAddresses(pfrom, MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND); } for (const CAddress &addr : vAddr) { PushAddress(*peer, addr); } return; } if (msg_type == NetMsgType::MEMPOOL) { // Only process received mempool messages if we advertise NODE_BLOOM // or if the peer has mempool permissions. if (!(peer->m_our_services & NODE_BLOOM) && !pfrom.HasPermission(NetPermissionFlags::Mempool)) { if (!pfrom.HasPermission(NetPermissionFlags::NoBan)) { LogPrint(BCLog::NET, "mempool request with bloom filters disabled, disconnect peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (m_connman.OutboundTargetReached(false) && !pfrom.HasPermission(NetPermissionFlags::Mempool)) { if (!pfrom.HasPermission(NetPermissionFlags::NoBan)) { LogPrint(BCLog::NET, "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom.GetId()); pfrom.fDisconnect = true; } return; } if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { LOCK(tx_relay->m_tx_inventory_mutex); tx_relay->m_send_mempool = true; } return; } if (msg_type == NetMsgType::PING) { if (pfrom.GetCommonVersion() > BIP0031_VERSION) { uint64_t nonce = 0; vRecv >> nonce; // Echo the message back with the nonce. This allows for two useful features: // // 1) A remote node can quickly check if the connection is operational // 2) Remote nodes can measure the latency of the network thread. If this node // is overloaded it won't respond to pings quickly and the remote node can // avoid sending us more work, like chain download requests. // // The nonce stops the remote getting confused between different pings: without // it, if the remote node sends a ping once per second and this node takes 5 // seconds to respond to each, the 5th ping the remote sends would appear to // return very quickly. MakeAndPushMessage(pfrom, NetMsgType::PONG, nonce); } return; } if (msg_type == NetMsgType::PONG) { const auto ping_end = time_received; uint64_t nonce = 0; size_t nAvail = vRecv.in_avail(); bool bPingFinished = false; std::string sProblem; if (nAvail >= sizeof(nonce)) { vRecv >> nonce; // Only process pong message if there is an outstanding ping (old ping without nonce should never pong) if (peer->m_ping_nonce_sent != 0) { if (nonce == peer->m_ping_nonce_sent) { // Matching pong received, this ping is no longer outstanding bPingFinished = true; const auto ping_time = ping_end - peer->m_ping_start.load(); if (ping_time.count() >= 0) { // Let connman know about this successful ping-pong pfrom.PongReceived(ping_time); } else { // This should never happen sProblem = "Timing mishap"; } } else { // Nonce mismatches are normal when pings are overlapping sProblem = "Nonce mismatch"; if (nonce == 0) { // This is most likely a bug in another implementation somewhere; cancel this ping bPingFinished = true; sProblem = "Nonce zero"; } } } else { sProblem = "Unsolicited pong without ping"; } } else { // This is most likely a bug in another implementation somewhere; cancel this ping bPingFinished = true; sProblem = "Short payload"; } if (!(sProblem.empty())) { LogPrint(BCLog::NET, "pong peer=%d: %s, %x expected, %x received, %u bytes\n", pfrom.GetId(), sProblem, peer->m_ping_nonce_sent, nonce, nAvail); } if (bPingFinished) { peer->m_ping_nonce_sent = 0; } return; } if (msg_type == NetMsgType::FILTERLOAD) { if (!(peer->m_our_services & NODE_BLOOM)) { LogPrint(BCLog::NET, "filterload received despite not offering bloom services from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } CBloomFilter filter; vRecv >> filter; if (!filter.IsWithinSizeConstraints()) { // There is no excuse for sending a too-large filter Misbehaving(*peer, 100, "too-large bloom filter"); } else if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { { LOCK(tx_relay->m_bloom_filter_mutex); tx_relay->m_bloom_filter.reset(new CBloomFilter(filter)); tx_relay->m_relay_txs = true; } pfrom.m_bloom_filter_loaded = true; pfrom.m_relays_txs = true; } return; } if (msg_type == NetMsgType::FILTERADD) { if (!(peer->m_our_services & NODE_BLOOM)) { LogPrint(BCLog::NET, "filteradd received despite not offering bloom services from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } std::vector vData; vRecv >> vData; // Nodes must NEVER send a data item > 520 bytes (the max size for a script data object, // and thus, the maximum size any matched object can have) in a filteradd message bool bad = false; if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) { bad = true; } else if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { LOCK(tx_relay->m_bloom_filter_mutex); if (tx_relay->m_bloom_filter) { tx_relay->m_bloom_filter->insert(vData); } else { bad = true; } } if (bad) { Misbehaving(*peer, 100, "bad filteradd message"); } return; } if (msg_type == NetMsgType::FILTERCLEAR) { if (!(peer->m_our_services & NODE_BLOOM)) { LogPrint(BCLog::NET, "filterclear received despite not offering bloom services from peer=%d; disconnecting\n", pfrom.GetId()); pfrom.fDisconnect = true; return; } auto tx_relay = peer->GetTxRelay(); if (!tx_relay) return; { LOCK(tx_relay->m_bloom_filter_mutex); tx_relay->m_bloom_filter = nullptr; tx_relay->m_relay_txs = true; } pfrom.m_bloom_filter_loaded = false; pfrom.m_relays_txs = true; return; } if (msg_type == NetMsgType::FEEFILTER) { CAmount newFeeFilter = 0; vRecv >> newFeeFilter; if (MoneyRange(newFeeFilter)) { if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { tx_relay->m_fee_filter_received = newFeeFilter; } LogPrint(BCLog::NET, "received: feefilter of %s from peer=%d\n", CFeeRate(newFeeFilter).ToString(), pfrom.GetId()); } return; } if (msg_type == NetMsgType::GETCFILTERS) { ProcessGetCFilters(pfrom, *peer, vRecv); return; } if (msg_type == NetMsgType::GETCFHEADERS) { ProcessGetCFHeaders(pfrom, *peer, vRecv); return; } if (msg_type == NetMsgType::GETCFCHECKPT) { ProcessGetCFCheckPt(pfrom, *peer, vRecv); return; } if (msg_type == NetMsgType::NOTFOUND) { std::vector vInv; vRecv >> vInv; if (vInv.size() <= MAX_PEER_TX_ANNOUNCEMENTS + MAX_BLOCKS_IN_TRANSIT_PER_PEER) { LOCK(::cs_main); for (CInv &inv : vInv) { if (inv.IsGenTxMsg()) { // If we receive a NOTFOUND message for a tx we requested, mark the announcement for it as // completed in TxRequestTracker. m_txrequest.ReceivedResponse(pfrom.GetId(), inv.hash); } } } return; } // Ignore unknown commands for extensibility LogPrint(BCLog::NET, "Unknown command \"%s\" from peer=%d\n", SanitizeString(msg_type), pfrom.GetId()); return; } bool PeerManagerImpl::MaybeDiscourageAndDisconnect(CNode& pnode, Peer& peer) { { LOCK(peer.m_misbehavior_mutex); // There's nothing to do if the m_should_discourage flag isn't set if (!peer.m_should_discourage) return false; peer.m_should_discourage = false; } // peer.m_misbehavior_mutex if (pnode.HasPermission(NetPermissionFlags::NoBan)) { // We never disconnect or discourage peers for bad behavior if they have NetPermissionFlags::NoBan permission LogPrintf("Warning: not punishing noban peer %d!\n", peer.m_id); return false; } if (pnode.IsManualConn()) { // We never disconnect or discourage manual peers for bad behavior LogPrintf("Warning: not punishing manually connected peer %d!\n", peer.m_id); return false; } if (pnode.addr.IsLocal()) { // We disconnect local peers for bad behavior but don't discourage (since that would discourage // all peers on the same local address) LogPrint(BCLog::NET, "Warning: disconnecting but not discouraging %s peer %d!\n", pnode.m_inbound_onion ? "inbound onion" : "local", peer.m_id); pnode.fDisconnect = true; return true; } // Normal case: Disconnect the peer and discourage all nodes sharing the address LogPrint(BCLog::NET, "Disconnecting and discouraging peer %d!\n", peer.m_id); if (m_banman) m_banman->Discourage(pnode.addr); m_connman.DisconnectNode(pnode.addr); return true; } bool PeerManagerImpl::ProcessMessages(CNode* pfrom, std::atomic& interruptMsgProc) { AssertLockHeld(g_msgproc_mutex); PeerRef peer = GetPeerRef(pfrom->GetId()); if (peer == nullptr) return false; { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) { ProcessGetData(*pfrom, *peer, interruptMsgProc); } } const bool processed_orphan = ProcessOrphanTx(*peer); if (pfrom->fDisconnect) return false; if (processed_orphan) return true; // this maintains the order of responses // and prevents m_getdata_requests to grow unbounded { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) return true; } // Don't bother if send buffer is too full to respond anyway if (pfrom->fPauseSend) return false; auto poll_result{pfrom->PollMessage()}; if (!poll_result) { // No message to process return false; } CNetMessage& msg{poll_result->first}; bool fMoreWork = poll_result->second; TRACE6(net, inbound_message, pfrom->GetId(), pfrom->m_addr_name.c_str(), pfrom->ConnectionTypeAsString().c_str(), msg.m_type.c_str(), msg.m_recv.size(), msg.m_recv.data() ); if (m_opts.capture_messages) { CaptureMessage(pfrom->addr, msg.m_type, MakeUCharSpan(msg.m_recv), /*is_incoming=*/true); } try { ProcessMessage(*pfrom, msg.m_type, msg.m_recv, msg.m_time, interruptMsgProc); if (interruptMsgProc) return false; { LOCK(peer->m_getdata_requests_mutex); if (!peer->m_getdata_requests.empty()) fMoreWork = true; } // Does this peer has an orphan ready to reconsider? // (Note: we may have provided a parent for an orphan provided // by another peer that was already processed; in that case, // the extra work may not be noticed, possibly resulting in an // unnecessary 100ms delay) if (m_orphanage.HaveTxToReconsider(peer->m_id)) fMoreWork = true; } catch (const std::exception& e) { LogPrint(BCLog::NET, "%s(%s, %u bytes): Exception '%s' (%s) caught\n", __func__, SanitizeString(msg.m_type), msg.m_message_size, e.what(), typeid(e).name()); } catch (...) { LogPrint(BCLog::NET, "%s(%s, %u bytes): Unknown exception caught\n", __func__, SanitizeString(msg.m_type), msg.m_message_size); } return fMoreWork; } void PeerManagerImpl::ConsiderEviction(CNode& pto, Peer& peer, std::chrono::seconds time_in_seconds) { AssertLockHeld(cs_main); CNodeState &state = *State(pto.GetId()); if (!state.m_chain_sync.m_protect && pto.IsOutboundOrBlockRelayConn() && state.fSyncStarted) { // This is an outbound peer subject to disconnection if they don't // announce a block with as much work as the current tip within // CHAIN_SYNC_TIMEOUT + HEADERS_RESPONSE_TIME seconds (note: if // their chain has more work than ours, we should sync to it, // unless it's invalid, in which case we should find that out and // disconnect from them elsewhere). if (state.pindexBestKnownBlock != nullptr && state.pindexBestKnownBlock->nChainWork >= m_chainman.ActiveChain().Tip()->nChainWork) { if (state.m_chain_sync.m_timeout != 0s) { state.m_chain_sync.m_timeout = 0s; state.m_chain_sync.m_work_header = nullptr; state.m_chain_sync.m_sent_getheaders = false; } } else if (state.m_chain_sync.m_timeout == 0s || (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 = m_chainman.ActiveChain().Tip(); state.m_chain_sync.m_sent_getheaders = false; } else if (state.m_chain_sync.m_timeout > 0s && 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); // Here, we assume that the getheaders message goes out, // because it'll either go out or be skipped because of a // getheaders in-flight already, in which case the peer should // still respond to us with a sufficiently high work chain tip. MaybeSendGetHeaders(pto, GetLocator(state.m_chain_sync.m_work_header->pprev), peer); 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()); state.m_chain_sync.m_sent_getheaders = true; // 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 PeerManagerImpl::EvictExtraOutboundPeers(std::chrono::seconds now) { // If we have any extra block-relay-only peers, disconnect the youngest unless // it's given us a block -- in which case, compare with the second-youngest, and // out of those two, disconnect the peer who least recently gave us a block. // The youngest block-relay-only peer would be the extra peer we connected // to temporarily in order to sync our tip; see net.cpp. // Note that we use higher nodeid as a measure for most recent connection. if (m_connman.GetExtraBlockRelayCount() > 0) { std::pair youngest_peer{-1, 0}, next_youngest_peer{-1, 0}; m_connman.ForEachNode([&](CNode* pnode) { if (!pnode->IsBlockOnlyConn() || pnode->fDisconnect) return; if (pnode->GetId() > youngest_peer.first) { next_youngest_peer = youngest_peer; youngest_peer.first = pnode->GetId(); youngest_peer.second = pnode->m_last_block_time; } }); NodeId to_disconnect = youngest_peer.first; if (youngest_peer.second > next_youngest_peer.second) { // Our newest block-relay-only peer gave us a block more recently; // disconnect our second youngest. to_disconnect = next_youngest_peer.first; } m_connman.ForNode(to_disconnect, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // Make sure we're not getting a block right now, and that // we've been connected long enough for this eviction to happen // at all. // Note that we only request blocks from a peer if we learn of a // valid headers chain with at least as much work as our tip. CNodeState *node_state = State(pnode->GetId()); if (node_state == nullptr || (now - pnode->m_connected >= MINIMUM_CONNECT_TIME && node_state->vBlocksInFlight.empty())) { pnode->fDisconnect = true; LogPrint(BCLog::NET, "disconnecting extra block-relay-only peer=%d (last block received at time %d)\n", pnode->GetId(), count_seconds(pnode->m_last_block_time)); return true; } else { LogPrint(BCLog::NET, "keeping block-relay-only peer=%d chosen for eviction (connect time: %d, blocks_in_flight: %d)\n", pnode->GetId(), count_seconds(pnode->m_connected), node_state->vBlocksInFlight.size()); } return false; }); } // Check whether we have too many outbound-full-relay peers if (m_connman.GetExtraFullOutboundCount() > 0) { // If we have more outbound-full-relay peers than we target, disconnect one. // Pick the outbound-full-relay peer that least recently announced // us a new block, with ties broken by choosing the more recent // connection (higher node id) // Protect peers from eviction if we don't have another connection // to their network, counting both outbound-full-relay and manual peers. NodeId worst_peer = -1; int64_t oldest_block_announcement = std::numeric_limits::max(); m_connman.ForEachNode([&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_connman.GetNodesMutex()) { AssertLockHeld(::cs_main); // Only consider outbound-full-relay peers that are not already // marked for disconnection if (!pnode->IsFullOutboundConn() || pnode->fDisconnect) return; CNodeState *state = State(pnode->GetId()); if (state == nullptr) return; // shouldn't be possible, but just in case // Don't evict our protected peers if (state->m_chain_sync.m_protect) return; // If this is the only connection on a particular network that is // OUTBOUND_FULL_RELAY or MANUAL, protect it. if (!m_connman.MultipleManualOrFullOutboundConns(pnode->addr.GetNetwork())) return; if (state->m_last_block_announcement < oldest_block_announcement || (state->m_last_block_announcement == oldest_block_announcement && pnode->GetId() > worst_peer)) { worst_peer = pnode->GetId(); oldest_block_announcement = state->m_last_block_announcement; } }); if (worst_peer != -1) { bool disconnected = m_connman.ForNode(worst_peer, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) { AssertLockHeld(::cs_main); // Only disconnect a peer that has been connected to us for // some reasonable fraction of our check-frequency, to give // it time for new information to have arrived. // Also don't disconnect any peer we're trying to download a // block from. CNodeState &state = *State(pnode->GetId()); if (now - pnode->m_connected > MINIMUM_CONNECT_TIME && state.vBlocksInFlight.empty()) { 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(), count_seconds(pnode->m_connected), state.vBlocksInFlight.size()); return false; } }); if (disconnected) { // If we disconnected an extra peer, that means we successfully // connected to at least one peer after the last time we // detected a stale tip. Don't try any more extra peers until // we next detect a stale tip, to limit the load we put on the // network from these extra connections. m_connman.SetTryNewOutboundPeer(false); } } } } void PeerManagerImpl::CheckForStaleTipAndEvictPeers() { LOCK(cs_main); auto now{GetTime()}; EvictExtraOutboundPeers(now); if (now > m_stale_tip_check_time) { // Check whether our tip is stale, and if so, allow using an extra // outbound peer if (!m_chainman.m_blockman.LoadingBlocks() && m_connman.GetNetworkActive() && m_connman.GetUseAddrmanOutgoing() && TipMayBeStale()) { LogPrintf("Potential stale tip detected, will try using extra outbound peer (last tip update: %d seconds ago)\n", count_seconds(now - m_last_tip_update.load())); m_connman.SetTryNewOutboundPeer(true); } else if (m_connman.GetTryNewOutboundPeer()) { m_connman.SetTryNewOutboundPeer(false); } m_stale_tip_check_time = now + STALE_CHECK_INTERVAL; } if (!m_initial_sync_finished && CanDirectFetch()) { m_connman.StartExtraBlockRelayPeers(); m_initial_sync_finished = true; } } void PeerManagerImpl::MaybeSendPing(CNode& node_to, Peer& peer, std::chrono::microseconds now) { if (m_connman.ShouldRunInactivityChecks(node_to, std::chrono::duration_cast(now)) && peer.m_ping_nonce_sent && now > peer.m_ping_start.load() + TIMEOUT_INTERVAL) { // The ping timeout is using mocktime. To disable the check during // testing, increase -peertimeout. LogPrint(BCLog::NET, "ping timeout: %fs peer=%d\n", 0.000001 * count_microseconds(now - peer.m_ping_start.load()), peer.m_id); node_to.fDisconnect = true; return; } bool pingSend = false; if (peer.m_ping_queued) { // RPC ping request by user pingSend = true; } if (peer.m_ping_nonce_sent == 0 && now > peer.m_ping_start.load() + PING_INTERVAL) { // Ping automatically sent as a latency probe & keepalive. pingSend = true; } if (pingSend) { uint64_t nonce; do { nonce = GetRand(); } while (nonce == 0); peer.m_ping_queued = false; peer.m_ping_start = now; if (node_to.GetCommonVersion() > BIP0031_VERSION) { peer.m_ping_nonce_sent = nonce; MakeAndPushMessage(node_to, NetMsgType::PING, nonce); } else { // Peer is too old to support ping command with nonce, pong will never arrive. peer.m_ping_nonce_sent = 0; MakeAndPushMessage(node_to, NetMsgType::PING); } } } void PeerManagerImpl::MaybeSendAddr(CNode& node, Peer& peer, std::chrono::microseconds current_time) { // Nothing to do for non-address-relay peers if (!peer.m_addr_relay_enabled) return; LOCK(peer.m_addr_send_times_mutex); // Periodically advertise our local address to the peer. if (fListen && !m_chainman.IsInitialBlockDownload() && peer.m_next_local_addr_send < current_time) { // If we've sent before, clear the bloom filter for the peer, so that our // self-announcement will actually go out. // This might be unnecessary if the bloom filter has already rolled // over since our last self-announcement, but there is only a small // bandwidth cost that we can incur by doing this (which happens // once a day on average). if (peer.m_next_local_addr_send != 0us) { peer.m_addr_known->reset(); } if (std::optional local_service = GetLocalAddrForPeer(node)) { CAddress local_addr{*local_service, peer.m_our_services, Now()}; PushAddress(peer, local_addr); } peer.m_next_local_addr_send = GetExponentialRand(current_time, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL); } // We sent an `addr` message to this peer recently. Nothing more to do. if (current_time <= peer.m_next_addr_send) return; peer.m_next_addr_send = GetExponentialRand(current_time, AVG_ADDRESS_BROADCAST_INTERVAL); if (!Assume(peer.m_addrs_to_send.size() <= MAX_ADDR_TO_SEND)) { // Should be impossible since we always check size before adding to // m_addrs_to_send. Recover by trimming the vector. peer.m_addrs_to_send.resize(MAX_ADDR_TO_SEND); } // Remove addr records that the peer already knows about, and add new // addrs to the m_addr_known filter on the same pass. auto addr_already_known = [&peer](const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex) { bool ret = peer.m_addr_known->contains(addr.GetKey()); if (!ret) peer.m_addr_known->insert(addr.GetKey()); return ret; }; peer.m_addrs_to_send.erase(std::remove_if(peer.m_addrs_to_send.begin(), peer.m_addrs_to_send.end(), addr_already_known), peer.m_addrs_to_send.end()); // No addr messages to send if (peer.m_addrs_to_send.empty()) return; if (peer.m_wants_addrv2) { MakeAndPushMessage(node, NetMsgType::ADDRV2, CAddress::V2_NETWORK(peer.m_addrs_to_send)); } else { MakeAndPushMessage(node, NetMsgType::ADDR, CAddress::V1_NETWORK(peer.m_addrs_to_send)); } peer.m_addrs_to_send.clear(); // we only send the big addr message once if (peer.m_addrs_to_send.capacity() > 40) { peer.m_addrs_to_send.shrink_to_fit(); } } void PeerManagerImpl::MaybeSendSendHeaders(CNode& node, Peer& peer) { // Delay sending SENDHEADERS (BIP 130) until we're done with an // initial-headers-sync with this peer. Receiving headers announcements for // new blocks while trying to sync their headers chain is problematic, // because of the state tracking done. if (!peer.m_sent_sendheaders && node.GetCommonVersion() >= SENDHEADERS_VERSION) { LOCK(cs_main); CNodeState &state = *State(node.GetId()); if (state.pindexBestKnownBlock != nullptr && state.pindexBestKnownBlock->nChainWork > m_chainman.MinimumChainWork()) { // 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) MakeAndPushMessage(node, NetMsgType::SENDHEADERS); peer.m_sent_sendheaders = true; } } } void PeerManagerImpl::MaybeSendFeefilter(CNode& pto, Peer& peer, std::chrono::microseconds current_time) { if (m_opts.ignore_incoming_txs) return; if (pto.GetCommonVersion() < FEEFILTER_VERSION) return; // peers with the forcerelay permission should not filter txs to us if (pto.HasPermission(NetPermissionFlags::ForceRelay)) return; // Don't send feefilter messages to outbound block-relay-only peers since they should never announce // transactions to us, regardless of feefilter state. if (pto.IsBlockOnlyConn()) return; CAmount currentFilter = m_mempool.GetMinFee().GetFeePerK(); if (m_chainman.IsInitialBlockDownload()) { // Received tx-inv messages are discarded when the active // chainstate is in IBD, so tell the peer to not send them. currentFilter = MAX_MONEY; } else { static const CAmount MAX_FILTER{m_fee_filter_rounder.round(MAX_MONEY)}; if (peer.m_fee_filter_sent == MAX_FILTER) { // Send the current filter if we sent MAX_FILTER previously // and made it out of IBD. peer.m_next_send_feefilter = 0us; } } if (current_time > peer.m_next_send_feefilter) { CAmount filterToSend = m_fee_filter_rounder.round(currentFilter); // We always have a fee filter of at least the min relay fee filterToSend = std::max(filterToSend, m_mempool.m_min_relay_feerate.GetFeePerK()); if (filterToSend != peer.m_fee_filter_sent) { MakeAndPushMessage(pto, NetMsgType::FEEFILTER, filterToSend); peer.m_fee_filter_sent = filterToSend; } peer.m_next_send_feefilter = GetExponentialRand(current_time, AVG_FEEFILTER_BROADCAST_INTERVAL); } // If the fee filter has changed substantially and it's still more than MAX_FEEFILTER_CHANGE_DELAY // until scheduled broadcast, then move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY. else if (current_time + MAX_FEEFILTER_CHANGE_DELAY < peer.m_next_send_feefilter && (currentFilter < 3 * peer.m_fee_filter_sent / 4 || currentFilter > 4 * peer.m_fee_filter_sent / 3)) { peer.m_next_send_feefilter = current_time + GetRandomDuration(MAX_FEEFILTER_CHANGE_DELAY); } } namespace { class CompareInvMempoolOrder { CTxMemPool* mp; bool m_wtxid_relay; public: explicit CompareInvMempoolOrder(CTxMemPool *_mempool, bool use_wtxid) { mp = _mempool; m_wtxid_relay = use_wtxid; } bool operator()(std::set::iterator a, std::set::iterator b) { /* As std::make_heap produces a max-heap, we want the entries with the * fewest ancestors/highest fee to sort later. */ return mp->CompareDepthAndScore(*b, *a, m_wtxid_relay); } }; } // namespace bool PeerManagerImpl::RejectIncomingTxs(const CNode& peer) const { // block-relay-only peers may never send txs to us if (peer.IsBlockOnlyConn()) return true; if (peer.IsFeelerConn()) return true; // In -blocksonly mode, peers need the 'relay' permission to send txs to us if (m_opts.ignore_incoming_txs && !peer.HasPermission(NetPermissionFlags::Relay)) return true; return false; } bool PeerManagerImpl::SetupAddressRelay(const CNode& node, Peer& peer) { // We don't participate in addr relay with outbound block-relay-only // connections to prevent providing adversaries with the additional // information of addr traffic to infer the link. if (node.IsBlockOnlyConn()) return false; if (!peer.m_addr_relay_enabled.exchange(true)) { // During version message processing (non-block-relay-only outbound peers) // or on first addr-related message we have received (inbound peers), initialize // m_addr_known. peer.m_addr_known = std::make_unique(5000, 0.001); } return true; } bool PeerManagerImpl::SendMessages(CNode* pto) { AssertLockHeld(g_msgproc_mutex); PeerRef peer = GetPeerRef(pto->GetId()); if (!peer) return false; const Consensus::Params& consensusParams = m_chainparams.GetConsensus(); // We must call MaybeDiscourageAndDisconnect first, to ensure that we'll // disconnect misbehaving peers even before the version handshake is complete. if (MaybeDiscourageAndDisconnect(*pto, *peer)) return true; // Don't send anything until the version handshake is complete if (!pto->fSuccessfullyConnected || pto->fDisconnect) return true; const auto current_time{GetTime()}; if (pto->IsAddrFetchConn() && current_time - pto->m_connected > 10 * AVG_ADDRESS_BROADCAST_INTERVAL) { LogPrint(BCLog::NET, "addrfetch connection timeout; disconnecting peer=%d\n", pto->GetId()); pto->fDisconnect = true; return true; } MaybeSendPing(*pto, *peer, current_time); // MaybeSendPing may have marked peer for disconnection if (pto->fDisconnect) return true; MaybeSendAddr(*pto, *peer, current_time); MaybeSendSendHeaders(*pto, *peer); { LOCK(cs_main); CNodeState &state = *State(pto->GetId()); // Start block sync if (m_chainman.m_best_header == nullptr) { m_chainman.m_best_header = m_chainman.ActiveChain().Tip(); } // Determine whether we might try initial headers sync or parallel // block download from this peer -- this mostly affects behavior while // in IBD (once out of IBD, we sync from all peers). bool sync_blocks_and_headers_from_peer = false; if (state.fPreferredDownload) { sync_blocks_and_headers_from_peer = true; } else if (CanServeBlocks(*peer) && !pto->IsAddrFetchConn()) { // Typically this is an inbound peer. If we don't have any outbound // peers, or if we aren't downloading any blocks from such peers, // then allow block downloads from this peer, too. // We prefer downloading blocks from outbound peers to avoid // putting undue load on (say) some home user who is just making // outbound connections to the network, but if our only source of // the latest blocks is from an inbound peer, we have to be sure to // eventually download it (and not just wait indefinitely for an // outbound peer to have it). if (m_num_preferred_download_peers == 0 || mapBlocksInFlight.empty()) { sync_blocks_and_headers_from_peer = true; } } if (!state.fSyncStarted && CanServeBlocks(*peer) && !m_chainman.m_blockman.LoadingBlocks()) { // Only actively request headers from a single peer, unless we're close to today. if ((nSyncStarted == 0 && sync_blocks_and_headers_from_peer) || m_chainman.m_best_header->Time() > NodeClock::now() - 24h) { const CBlockIndex* pindexStart = m_chainman.m_best_header; /* 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 m_chainman.m_best_header and got back an empty response. */ if (pindexStart->pprev) pindexStart = pindexStart->pprev; if (MaybeSendGetHeaders(*pto, GetLocator(pindexStart), *peer)) { LogPrint(BCLog::NET, "initial getheaders (%d) to peer=%d (startheight:%d)\n", pindexStart->nHeight, pto->GetId(), peer->m_starting_height); state.fSyncStarted = true; peer->m_headers_sync_timeout = current_time + HEADERS_DOWNLOAD_TIMEOUT_BASE + ( // Convert HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER to microseconds before scaling // to maintain precision std::chrono::microseconds{HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER} * Ticks(NodeClock::now() - m_chainman.m_best_header->Time()) / consensusParams.nPowTargetSpacing ); nSyncStarted++; } } } // // Try sending block announcements via headers // { // If we have no more 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(peer->m_block_inv_mutex); std::vector vHeaders; bool fRevertToInv = ((!peer->m_prefers_headers && (!state.m_requested_hb_cmpctblocks || peer->m_blocks_for_headers_relay.size() > 1)) || peer->m_blocks_for_headers_relay.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 m_chainman.ActiveChain(), give up. for (const uint256& hash : peer->m_blocks_for_headers_relay) { const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(hash); assert(pindex); if (m_chainman.ActiveChain()[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 m_blocks_for_headers_relay. // 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.emplace_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.emplace_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.m_requested_hb_cmpctblocks) { // 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()); std::optional cached_cmpctblock_msg; { LOCK(m_most_recent_block_mutex); if (m_most_recent_block_hash == pBestIndex->GetBlockHash()) { cached_cmpctblock_msg = NetMsg::Make(NetMsgType::CMPCTBLOCK, *m_most_recent_compact_block); } } if (cached_cmpctblock_msg.has_value()) { PushMessage(*pto, std::move(cached_cmpctblock_msg.value())); } else { CBlock block; const bool ret{m_chainman.m_blockman.ReadBlockFromDisk(block, *pBestIndex)}; assert(ret); CBlockHeaderAndShortTxIDs cmpctblock{block}; MakeAndPushMessage(*pto, NetMsgType::CMPCTBLOCK, cmpctblock); } state.pindexBestHeaderSent = pBestIndex; } else if (peer->m_prefers_headers) { 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()); } MakeAndPushMessage(*pto, NetMsgType::HEADERS, TX_WITH_WITNESS(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 m_blocks_for_headers_relay was our tip at some point // in the past. if (!peer->m_blocks_for_headers_relay.empty()) { const uint256& hashToAnnounce = peer->m_blocks_for_headers_relay.back(); const CBlockIndex* pindex = m_chainman.m_blockman.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 (m_chainman.ActiveChain()[pindex->nHeight] != pindex) { LogPrint(BCLog::NET, "Announcing block %s not on main chain (tip=%s)\n", hashToAnnounce.ToString(), m_chainman.ActiveChain().Tip()->GetBlockHash().ToString()); } // If the peer's chain has this block, don't inv it back. if (!PeerHasHeader(&state, pindex)) { peer->m_blocks_for_inv_relay.push_back(hashToAnnounce); LogPrint(BCLog::NET, "%s: sending inv peer=%d hash=%s\n", __func__, pto->GetId(), hashToAnnounce.ToString()); } } } peer->m_blocks_for_headers_relay.clear(); } // // Message: inventory // std::vector vInv; { LOCK(peer->m_block_inv_mutex); vInv.reserve(std::max(peer->m_blocks_for_inv_relay.size(), INVENTORY_BROADCAST_TARGET)); // Add blocks for (const uint256& hash : peer->m_blocks_for_inv_relay) { vInv.emplace_back(MSG_BLOCK, hash); if (vInv.size() == MAX_INV_SZ) { MakeAndPushMessage(*pto, NetMsgType::INV, vInv); vInv.clear(); } } peer->m_blocks_for_inv_relay.clear(); } if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) { LOCK(tx_relay->m_tx_inventory_mutex); // Check whether periodic sends should happen bool fSendTrickle = pto->HasPermission(NetPermissionFlags::NoBan); if (tx_relay->m_next_inv_send_time < current_time) { fSendTrickle = true; if (pto->IsInboundConn()) { tx_relay->m_next_inv_send_time = NextInvToInbounds(current_time, INBOUND_INVENTORY_BROADCAST_INTERVAL); } else { tx_relay->m_next_inv_send_time = GetExponentialRand(current_time, OUTBOUND_INVENTORY_BROADCAST_INTERVAL); } } // Time to send but the peer has requested we not relay transactions. if (fSendTrickle) { LOCK(tx_relay->m_bloom_filter_mutex); if (!tx_relay->m_relay_txs) tx_relay->m_tx_inventory_to_send.clear(); } // Respond to BIP35 mempool requests if (fSendTrickle && tx_relay->m_send_mempool) { auto vtxinfo = m_mempool.infoAll(); tx_relay->m_send_mempool = false; const CFeeRate filterrate{tx_relay->m_fee_filter_received.load()}; LOCK(tx_relay->m_bloom_filter_mutex); for (const auto& txinfo : vtxinfo) { CInv inv{ peer->m_wtxid_relay ? MSG_WTX : MSG_TX, peer->m_wtxid_relay ? txinfo.tx->GetWitnessHash().ToUint256() : txinfo.tx->GetHash().ToUint256(), }; tx_relay->m_tx_inventory_to_send.erase(inv.hash); // Don't send transactions that peers will not put into their mempool if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) { continue; } if (tx_relay->m_bloom_filter) { if (!tx_relay->m_bloom_filter->IsRelevantAndUpdate(*txinfo.tx)) continue; } tx_relay->m_tx_inventory_known_filter.insert(inv.hash); vInv.push_back(inv); if (vInv.size() == MAX_INV_SZ) { MakeAndPushMessage(*pto, NetMsgType::INV, vInv); vInv.clear(); } } } // Determine transactions to relay if (fSendTrickle) { // Produce a vector with all candidates for sending std::vector::iterator> vInvTx; vInvTx.reserve(tx_relay->m_tx_inventory_to_send.size()); for (std::set::iterator it = tx_relay->m_tx_inventory_to_send.begin(); it != tx_relay->m_tx_inventory_to_send.end(); it++) { vInvTx.push_back(it); } const CFeeRate filterrate{tx_relay->m_fee_filter_received.load()}; // Topologically and fee-rate sort the inventory we send for privacy and priority reasons. // A heap is used so that not all items need sorting if only a few are being sent. CompareInvMempoolOrder compareInvMempoolOrder(&m_mempool, peer->m_wtxid_relay); std::make_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder); // No reason to drain out at many times the network's capacity, // especially since we have many peers and some will draw much shorter delays. unsigned int nRelayedTransactions = 0; LOCK(tx_relay->m_bloom_filter_mutex); size_t broadcast_max{INVENTORY_BROADCAST_TARGET + (tx_relay->m_tx_inventory_to_send.size()/1000)*5}; broadcast_max = std::min(INVENTORY_BROADCAST_MAX, broadcast_max); while (!vInvTx.empty() && nRelayedTransactions < broadcast_max) { // Fetch the top element from the heap std::pop_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder); std::set::iterator it = vInvTx.back(); vInvTx.pop_back(); uint256 hash = *it; CInv inv(peer->m_wtxid_relay ? MSG_WTX : MSG_TX, hash); // Remove it from the to-be-sent set tx_relay->m_tx_inventory_to_send.erase(it); // Check if not in the filter already if (tx_relay->m_tx_inventory_known_filter.contains(hash)) { continue; } // Not in the mempool anymore? don't bother sending it. auto txinfo = m_mempool.info(ToGenTxid(inv)); if (!txinfo.tx) { continue; } // Peer told you to not send transactions at that feerate? Don't bother sending it. if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) { continue; } if (tx_relay->m_bloom_filter && !tx_relay->m_bloom_filter->IsRelevantAndUpdate(*txinfo.tx)) continue; // Send vInv.push_back(inv); nRelayedTransactions++; if (vInv.size() == MAX_INV_SZ) { MakeAndPushMessage(*pto, NetMsgType::INV, vInv); vInv.clear(); } tx_relay->m_tx_inventory_known_filter.insert(hash); } // Ensure we'll respond to GETDATA requests for anything we've just announced LOCK(m_mempool.cs); tx_relay->m_last_inv_sequence = m_mempool.GetSequence(); } } if (!vInv.empty()) MakeAndPushMessage(*pto, NetMsgType::INV, vInv); // Detect whether we're stalling auto stalling_timeout = m_block_stalling_timeout.load(); if (state.m_stalling_since.count() && state.m_stalling_since < current_time - 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%s is stalling block download, disconnecting\n", pto->GetId(), fLogIPs ? strprintf(" peeraddr=%s", pto->addr.ToStringAddrPort()) : ""); pto->fDisconnect = true; // Increase timeout for the next peer so that we don't disconnect multiple peers if our own // bandwidth is insufficient. const auto new_timeout = std::min(2 * stalling_timeout, BLOCK_STALLING_TIMEOUT_MAX); if (stalling_timeout != new_timeout && m_block_stalling_timeout.compare_exchange_strong(stalling_timeout, new_timeout)) { LogPrint(BCLog::NET, "Increased stalling timeout temporarily to %d seconds\n", count_seconds(new_timeout)); } return true; } // In case there is a block that has been in flight from this peer for block_interval * (1 + 0.5 * N) // (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 = m_peers_downloading_from - 1; if (current_time > state.m_downloading_since + std::chrono::seconds{consensusParams.nPowTargetSpacing} * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) { LogPrintf("Timeout downloading block %s from peer=%d%s, disconnecting\n", queuedBlock.pindex->GetBlockHash().ToString(), pto->GetId(), fLogIPs ? strprintf(" peeraddr=%s", pto->addr.ToStringAddrPort()) : ""); pto->fDisconnect = true; return true; } } // Check for headers sync timeouts if (state.fSyncStarted && peer->m_headers_sync_timeout < std::chrono::microseconds::max()) { // Detect whether this is a stalling initial-headers-sync peer if (m_chainman.m_best_header->Time() <= NodeClock::now() - 24h) { if (current_time > peer->m_headers_sync_timeout && nSyncStarted == 1 && (m_num_preferred_download_peers - state.fPreferredDownload >= 1)) { // Disconnect a peer (without NetPermissionFlags::NoBan permission) if it is our only sync peer, // and we have others we could be using instead. // Note: If all our peers are inbound, then we won't // disconnect our sync peer for stalling; we have bigger // problems if we can't get any outbound peers. if (!pto->HasPermission(NetPermissionFlags::NoBan)) { LogPrintf("Timeout downloading headers from peer=%d%s, disconnecting\n", pto->GetId(), fLogIPs ? strprintf(" peeraddr=%s", pto->addr.ToStringAddrPort()) : ""); pto->fDisconnect = true; return true; } else { LogPrintf("Timeout downloading headers from noban peer=%d%s, not disconnecting\n", pto->GetId(), fLogIPs ? strprintf(" peeraddr=%s", pto->addr.ToStringAddrPort()) : ""); // 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--; peer->m_headers_sync_timeout = 0us; } } } else { // After we've caught up once, reset the timeout so we can't trigger // disconnect later. peer->m_headers_sync_timeout = std::chrono::microseconds::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, *peer, GetTime()); // // Message: getdata (blocks) // std::vector vGetData; if (CanServeBlocks(*peer) && ((sync_blocks_and_headers_from_peer && !IsLimitedPeer(*peer)) || !m_chainman.IsInitialBlockDownload()) && state.vBlocksInFlight.size() < MAX_BLOCKS_IN_TRANSIT_PER_PEER) { std::vector vToDownload; NodeId staller = -1; auto get_inflight_budget = [&state]() { return std::max(0, MAX_BLOCKS_IN_TRANSIT_PER_PEER - static_cast(state.vBlocksInFlight.size())); }; // If a snapshot chainstate is in use, we want to find its next blocks // before the background chainstate to prioritize getting to network tip. FindNextBlocksToDownload(*peer, get_inflight_budget(), vToDownload, staller); if (m_chainman.BackgroundSyncInProgress() && !IsLimitedPeer(*peer)) { TryDownloadingHistoricalBlocks( *peer, get_inflight_budget(), vToDownload, m_chainman.GetBackgroundSyncTip(), Assert(m_chainman.GetSnapshotBaseBlock())); } for (const CBlockIndex *pindex : vToDownload) { uint32_t nFetchFlags = GetFetchFlags(*peer); vGetData.emplace_back(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash()); BlockRequested(pto->GetId(), *pindex); LogPrint(BCLog::NET, "Requesting block %s (%d) peer=%d\n", pindex->GetBlockHash().ToString(), pindex->nHeight, pto->GetId()); } if (state.vBlocksInFlight.empty() && staller != -1) { if (State(staller)->m_stalling_since == 0us) { State(staller)->m_stalling_since = current_time; LogPrint(BCLog::NET, "Stall started peer=%d\n", staller); } } } // // Message: getdata (transactions) // std::vector> expired; auto requestable = m_txrequest.GetRequestable(pto->GetId(), current_time, &expired); for (const auto& entry : expired) { LogPrint(BCLog::NET, "timeout of inflight %s %s from peer=%d\n", entry.second.IsWtxid() ? "wtx" : "tx", entry.second.GetHash().ToString(), entry.first); } for (const GenTxid& gtxid : requestable) { // Exclude m_recent_rejects_reconsiderable: we may be requesting a missing parent // that was previously rejected for being too low feerate. if (!AlreadyHaveTx(gtxid, /*include_reconsiderable=*/false)) { LogPrint(BCLog::NET, "Requesting %s %s peer=%d\n", gtxid.IsWtxid() ? "wtx" : "tx", gtxid.GetHash().ToString(), pto->GetId()); vGetData.emplace_back(gtxid.IsWtxid() ? MSG_WTX : (MSG_TX | GetFetchFlags(*peer)), gtxid.GetHash()); if (vGetData.size() >= MAX_GETDATA_SZ) { MakeAndPushMessage(*pto, NetMsgType::GETDATA, vGetData); vGetData.clear(); } m_txrequest.RequestedTx(pto->GetId(), gtxid.GetHash(), current_time + GETDATA_TX_INTERVAL); } else { // We have already seen this transaction, no need to download. This is just a belt-and-suspenders, as // this should already be called whenever a transaction becomes AlreadyHaveTx(). m_txrequest.ForgetTxHash(gtxid.GetHash()); } } if (!vGetData.empty()) MakeAndPushMessage(*pto, NetMsgType::GETDATA, vGetData); } // release cs_main MaybeSendFeefilter(*pto, *peer, current_time); return true; }