1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-present The Bitcoin Core developers
3 // Distributed under the MIT software license, see the accompanying
4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 6 #include <net_processing.h>
7 8 #include <addrman.h>
9 #include <arith_uint256.h>
10 #include <banman.h>
11 #include <blockencodings.h>
12 #include <blockfilter.h>
13 #include <chain.h>
14 #include <chainparams.h>
15 #include <common/bloom.h>
16 #include <consensus/amount.h>
17 #include <consensus/params.h>
18 #include <consensus/validation.h>
19 #include <core_memusage.h>
20 #include <crypto/siphash.h>
21 #include <deploymentstatus.h>
22 #include <flatfile.h>
23 #include <headerssync.h>
24 #include <index/blockfilterindex.h>
25 #include <kernel/types.h>
26 #include <logging.h>
27 #include <merkleblock.h>
28 #include <net.h>
29 #include <net_permissions.h>
30 #include <netaddress.h>
31 #include <netbase.h>
32 #include <netmessagemaker.h>
33 #include <node/blockstorage.h>
34 #include <node/connection_types.h>
35 #include <node/protocol_version.h>
36 #include <node/timeoffsets.h>
37 #include <node/txdownloadman.h>
38 #include <node/txorphanage.h>
39 #include <node/txreconciliation.h>
40 #include <node/warnings.h>
41 #include <policy/feerate.h>
42 #include <policy/fees/block_policy_estimator.h>
43 #include <policy/packages.h>
44 #include <policy/policy.h>
45 #include <primitives/block.h>
46 #include <primitives/transaction.h>
47 #include <private_broadcast.h>
48 #include <protocol.h>
49 #include <random.h>
50 #include <scheduler.h>
51 #include <script/script.h>
52 #include <serialize.h>
53 #include <span.h>
54 #include <streams.h>
55 #include <sync.h>
56 #include <tinyformat.h>
57 #include <txmempool.h>
58 #include <uint256.h>
59 #include <util/check.h>
60 #include <util/strencodings.h>
61 #include <util/time.h>
62 #include <util/trace.h>
63 #include <validation.h>
64 65 #include <algorithm>
66 #include <array>
67 #include <atomic>
68 #include <compare>
69 #include <cstddef>
70 #include <deque>
71 #include <exception>
72 #include <functional>
73 #include <future>
74 #include <initializer_list>
75 #include <iterator>
76 #include <limits>
77 #include <list>
78 #include <map>
79 #include <memory>
80 #include <optional>
81 #include <queue>
82 #include <ranges>
83 #include <ratio>
84 #include <set>
85 #include <span>
86 #include <typeinfo>
87 #include <utility>
88 89 using kernel::ChainstateRole;
90 using namespace util::hex_literals;
91 92 TRACEPOINT_SEMAPHORE(net, inbound_message);
93 TRACEPOINT_SEMAPHORE(net, misbehaving_connection);
94 95 /** Headers download timeout.
96 * Timeout = base + per_header * (expected number of headers) */
97 static constexpr auto HEADERS_DOWNLOAD_TIMEOUT_BASE = 15min;
98 static constexpr auto HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1ms;
99 /** How long to wait for a peer to respond to a getheaders request */
100 static constexpr auto HEADERS_RESPONSE_TIME{2min};
101 /** Protect at least this many outbound peers from disconnection due to slow/
102 * behind headers chain.
103 */
104 static constexpr int32_t MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT = 4;
105 /** Timeout for (unprotected) outbound peers to sync to our chainwork */
106 static constexpr auto CHAIN_SYNC_TIMEOUT{20min};
107 /** How frequently to check for stale tips */
108 static constexpr auto STALE_CHECK_INTERVAL{10min};
109 /** How frequently to check for extra outbound peers and disconnect */
110 static constexpr auto EXTRA_PEER_CHECK_INTERVAL{45s};
111 /** Minimum time an outbound-peer-eviction candidate must be connected for, in order to evict */
112 static constexpr auto MINIMUM_CONNECT_TIME{30s};
113 /** SHA256("main address relay")[0:8] */
114 static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL;
115 /// Age after which a stale block will no longer be served if requested as
116 /// protection against fingerprinting. Set to one month, denominated in seconds.
117 static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60;
118 /// Age after which a block is considered historical for purposes of rate
119 /// limiting block relay. Set to one week, denominated in seconds.
120 static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60;
121 /** Time between pings automatically sent out for latency probing and keepalive */
122 static constexpr auto PING_INTERVAL{2min};
123 /** The maximum number of entries in a locator */
124 static const unsigned int MAX_LOCATOR_SZ = 101;
125 /** The maximum number of entries in an 'inv' protocol message */
126 static const unsigned int MAX_INV_SZ = 50000;
127 /** Limit to avoid sending big packets. Not used in processing incoming GETDATA for compatibility */
128 static const unsigned int MAX_GETDATA_SZ = 1000;
129 /** Number of blocks that can be requested at any given time from a single peer. */
130 static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
131 /** Default time during which a peer must stall block download progress before being disconnected.
132 * the actual timeout is increased temporarily if peers are disconnected for hitting the timeout */
133 static constexpr auto BLOCK_STALLING_TIMEOUT_DEFAULT{2s};
134 /** Maximum timeout for stalling block download. */
135 static constexpr auto BLOCK_STALLING_TIMEOUT_MAX{64s};
136 /** Maximum depth of blocks we're willing to serve as compact blocks to peers
137 * when requested. For older blocks, a regular BLOCK response will be sent. */
138 static const int MAX_CMPCTBLOCK_DEPTH = 5;
139 /** Maximum depth of blocks we're willing to respond to GETBLOCKTXN requests for. */
140 static const int MAX_BLOCKTXN_DEPTH = 10;
141 static_assert(MAX_BLOCKTXN_DEPTH <= MIN_BLOCKS_TO_KEEP, "MAX_BLOCKTXN_DEPTH too high");
142 /** Size of the "block download window": how far ahead of our current height do we fetch?
143 * Larger windows tolerate larger download speed differences between peer, but increase the potential
144 * degree of disordering of blocks on disk (which make reindexing and pruning harder). We'll probably
145 * want to make this a per-peer adaptive value at some point. */
146 static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
147 /** Block download timeout base, expressed in multiples of the block interval (i.e. 10 min) */
148 static constexpr double BLOCK_DOWNLOAD_TIMEOUT_BASE = 1;
149 /** Additional block download timeout per parallel downloading peer (i.e. 5 min) */
150 static constexpr double BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 0.5;
151 /** Maximum number of headers to announce when relaying blocks with headers message.*/
152 static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
153 /** Minimum blocks required to signal NODE_NETWORK_LIMITED */
154 static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
155 /** Window, in blocks, for connecting to NODE_NETWORK_LIMITED peers */
156 static const unsigned int NODE_NETWORK_LIMITED_ALLOW_CONN_BLOCKS = 144;
157 /** Average delay between local address broadcasts */
158 static constexpr auto AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24h};
159 /** Average delay between peer address broadcasts */
160 static constexpr auto AVG_ADDRESS_BROADCAST_INTERVAL{30s};
161 /** Delay between rotating the peers we relay a particular address to */
162 static constexpr auto ROTATE_ADDR_RELAY_DEST_INTERVAL{24h};
163 /** Average delay between trickled inventory transmissions for inbound peers.
164 * Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */
165 static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL{5s};
166 /** Average delay between trickled inventory transmissions for outbound peers.
167 * Use a smaller delay as there is less privacy concern for them.
168 * Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */
169 static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL{2s};
170 /** Maximum rate of inventory items to send per second.
171 * Limits the impact of low-fee transaction floods. */
172 static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND{14};
173 /** Target number of tx inventory items to send per transmission. */
174 static constexpr unsigned int INVENTORY_BROADCAST_TARGET = INVENTORY_BROADCAST_PER_SECOND * count_seconds(INBOUND_INVENTORY_BROADCAST_INTERVAL);
175 /** Maximum number of inventory items to send per transmission. */
176 static constexpr unsigned int INVENTORY_BROADCAST_MAX = 1000;
177 static_assert(INVENTORY_BROADCAST_MAX >= INVENTORY_BROADCAST_TARGET, "INVENTORY_BROADCAST_MAX too low");
178 static_assert(INVENTORY_BROADCAST_MAX <= node::MAX_PEER_TX_ANNOUNCEMENTS, "INVENTORY_BROADCAST_MAX too high");
179 /** Average delay between feefilter broadcasts in seconds. */
180 static constexpr auto AVG_FEEFILTER_BROADCAST_INTERVAL{10min};
181 /** Maximum feefilter broadcast delay after significant change. */
182 static constexpr auto MAX_FEEFILTER_CHANGE_DELAY{5min};
183 /** Maximum number of compact filters that may be requested with one getcfilters. See BIP 157. */
184 static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000;
185 /** Maximum number of cf hashes that may be requested with one getcfheaders. See BIP 157. */
186 static constexpr uint32_t MAX_GETCFHEADERS_SIZE = 2000;
187 /** the maximum percentage of addresses from our addrman to return in response to a getaddr message. */
188 static constexpr size_t MAX_PCT_ADDR_TO_SEND = 23;
189 /** The maximum number of address records permitted in an ADDR message. */
190 static constexpr size_t MAX_ADDR_TO_SEND{1000};
191 /** The maximum rate of address records we're willing to process on average. Can be bypassed using
192 * the NetPermissionFlags::Addr permission. */
193 static constexpr double MAX_ADDR_RATE_PER_SECOND{0.1};
194 /** The soft limit of the address processing token bucket (the regular MAX_ADDR_RATE_PER_SECOND
195 * based increments won't go above this, but the MAX_ADDR_TO_SEND increment following GETADDR
196 * is exempt from this limit). */
197 static constexpr size_t MAX_ADDR_PROCESSING_TOKEN_BUCKET{MAX_ADDR_TO_SEND};
198 /** For private broadcast, send a transaction to this many peers. */
199 static constexpr size_t NUM_PRIVATE_BROADCAST_PER_TX{3};
200 /** Private broadcast connections must complete within this time. Disconnect the peer if it takes longer. */
201 static constexpr auto PRIVATE_BROADCAST_MAX_CONNECTION_LIFETIME{3min};
202 203 // Internal stuff
204 namespace {
205 /** Blocks that are in flight, and that are in the queue to be downloaded. */
206 struct QueuedBlock {
207 /** BlockIndex. We must have this since we only request blocks when we've already validated the header. */
208 const CBlockIndex* pindex;
209 /** Optional, used for CMPCTBLOCK downloads */
210 std::unique_ptr<PartiallyDownloadedBlock> partialBlock;
211 };
212 213 /**
214 * Data structure for an individual peer. This struct is not protected by
215 * cs_main since it does not contain validation-critical data.
216 *
217 * Memory is owned by shared pointers and this object is destructed when
218 * the refcount drops to zero.
219 *
220 * Mutexes inside this struct must not be held when locking m_peer_mutex.
221 *
222 * TODO: move most members from CNodeState to this structure.
223 * TODO: move remaining application-layer data members from CNode to this structure.
224 */
225 struct Peer {
226 /** Same id as the CNode object for this peer */
227 const NodeId m_id{0};
228 229 /** Services we offered to this peer.
230 *
231 * This is supplied by CConnman during peer initialization. It's const
232 * because there is no protocol defined for renegotiating services
233 * initially offered to a peer. The set of local services we offer should
234 * not change after initialization.
235 *
236 * An interesting example of this is NODE_NETWORK and initial block
237 * download: a node which starts up from scratch doesn't have any blocks
238 * to serve, but still advertises NODE_NETWORK because it will eventually
239 * fulfill this role after IBD completes. P2P code is written in such a
240 * way that it can gracefully handle peers who don't make good on their
241 * service advertisements. */
242 const ServiceFlags m_our_services;
243 /** Services this peer offered to us. */
244 std::atomic<ServiceFlags> m_their_services{NODE_NONE};
245 246 //! Whether this peer is an inbound connection
247 const bool m_is_inbound;
248 249 /** Protects misbehavior data members */
250 Mutex m_misbehavior_mutex;
251 /** Whether this peer should be disconnected and marked as discouraged (unless it has NetPermissionFlags::NoBan permission). */
252 bool m_should_discourage GUARDED_BY(m_misbehavior_mutex){false};
253 254 /** Protects block inventory data members */
255 Mutex m_block_inv_mutex;
256 /** List of blocks that we'll announce via an `inv` message.
257 * There is no final sorting before sending, as they are always sent
258 * immediately and in the order requested. */
259 std::vector<uint256> m_blocks_for_inv_relay GUARDED_BY(m_block_inv_mutex);
260 /** Unfiltered list of blocks that we'd like to announce via a `headers`
261 * message. If we can't announce via a `headers` message, we'll fall back to
262 * announcing via `inv`. */
263 std::vector<uint256> m_blocks_for_headers_relay GUARDED_BY(m_block_inv_mutex);
264 /** The final block hash that we sent in an `inv` message to this peer.
265 * When the peer requests this block, we send an `inv` message to trigger
266 * the peer to request the next sequence of block hashes.
267 * Most peers use headers-first syncing, which doesn't use this mechanism */
268 uint256 m_continuation_block GUARDED_BY(m_block_inv_mutex) {};
269 270 /** Set to true once initial VERSION message was sent (only relevant for outbound peers). */
271 bool m_outbound_version_message_sent GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false};
272 273 /** The pong reply we're expecting, or 0 if no pong expected. */
274 std::atomic<uint64_t> m_ping_nonce_sent{0};
275 /** When the last ping was sent, or 0 if no ping was ever sent */
276 std::atomic<NodeClock::time_point> m_ping_start{NodeClock::epoch};
277 /** Whether a ping has been requested by the user */
278 std::atomic<bool> m_ping_queued{false};
279 280 /** Whether this peer relays txs via wtxid */
281 std::atomic<bool> m_wtxid_relay{false};
282 /** The feerate in the most recent BIP133 `feefilter` message sent to the peer.
283 * It is *not* a p2p protocol violation for the peer to send us
284 * transactions with a lower fee rate than this. See BIP133. */
285 CAmount m_fee_filter_sent GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0};
286 /** Timestamp after which we will send the next BIP133 `feefilter` message
287 * to the peer. */
288 std::chrono::microseconds m_next_send_feefilter GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0};
289 290 struct TxRelay {
291 mutable RecursiveMutex m_bloom_filter_mutex;
292 /** Whether we relay transactions to this peer. */
293 bool m_relay_txs GUARDED_BY(m_bloom_filter_mutex){false};
294 /** A bloom filter for which transactions to announce to the peer. See BIP37. */
295 std::unique_ptr<CBloomFilter> m_bloom_filter PT_GUARDED_BY(m_bloom_filter_mutex) GUARDED_BY(m_bloom_filter_mutex){nullptr};
296 297 mutable RecursiveMutex m_tx_inventory_mutex;
298 /** A filter of all the (w)txids that the peer has announced to
299 * us or we have announced to the peer. We use this to avoid announcing
300 * the same (w)txid to a peer that already has the transaction. */
301 CRollingBloomFilter m_tx_inventory_known_filter GUARDED_BY(m_tx_inventory_mutex){50000, 0.000001};
302 /** Set of wtxids we still have to announce. For non-wtxid-relay peers,
303 * we retrieve the txid from the corresponding mempool transaction when
304 * constructing the `inv` message. We use the mempool to sort transactions
305 * in dependency order before relay, so this does not have to be sorted. */
306 std::set<Wtxid> m_tx_inventory_to_send GUARDED_BY(m_tx_inventory_mutex);
307 /** Whether the peer has requested us to send our complete mempool. Only
308 * permitted if the peer has NetPermissionFlags::Mempool or we advertise
309 * NODE_BLOOM. See BIP35. */
310 bool m_send_mempool GUARDED_BY(m_tx_inventory_mutex){false};
311 /** The next time after which we will send an `inv` message containing
312 * transaction announcements to this peer. */
313 std::chrono::microseconds m_next_inv_send_time GUARDED_BY(m_tx_inventory_mutex){0};
314 /** The mempool sequence num at which we sent the last `inv` message to this peer.
315 * Can relay txs with lower sequence numbers than this (see CTxMempool::info_for_relay). */
316 uint64_t m_last_inv_sequence GUARDED_BY(m_tx_inventory_mutex){1};
317 318 /** Minimum fee rate with which to filter transaction announcements to this node. See BIP133. */
319 std::atomic<CAmount> m_fee_filter_received{0};
320 };
321 322 /* Initializes a TxRelay struct for this peer. Can be called at most once for a peer. */
323 TxRelay* SetTxRelay() EXCLUSIVE_LOCKS_REQUIRED(!m_tx_relay_mutex)
324 {
325 LOCK(m_tx_relay_mutex);
326 Assume(!m_tx_relay);
327 m_tx_relay = std::make_unique<Peer::TxRelay>();
328 return m_tx_relay.get();
329 };
330 331 TxRelay* GetTxRelay() EXCLUSIVE_LOCKS_REQUIRED(!m_tx_relay_mutex)
332 {
333 return WITH_LOCK(m_tx_relay_mutex, return m_tx_relay.get());
334 };
335 336 /** A vector of addresses to send to the peer, limited to MAX_ADDR_TO_SEND. */
337 std::vector<CAddress> m_addrs_to_send GUARDED_BY(NetEventsInterface::g_msgproc_mutex);
338 /** Probabilistic filter to track recent addr messages relayed with this
339 * peer. Used to avoid relaying redundant addresses to this peer.
340 *
341 * We initialize this filter for outbound peers (other than
342 * block-relay-only connections) or when an inbound peer sends us an
343 * address related message (ADDR, ADDRV2, GETADDR).
344 *
345 * Presence of this filter must correlate with m_addr_relay_enabled.
346 **/
347 std::unique_ptr<CRollingBloomFilter> m_addr_known GUARDED_BY(NetEventsInterface::g_msgproc_mutex);
348 /** Whether we are participating in address relay with this connection.
349 *
350 * We set this bool to true for outbound peers (other than
351 * block-relay-only connections), or when an inbound peer sends us an
352 * address related message (ADDR, ADDRV2, GETADDR).
353 *
354 * We use this bool to decide whether a peer is eligible for gossiping
355 * addr messages. This avoids relaying to peers that are unlikely to
356 * forward them, effectively blackholing self announcements. Reasons
357 * peers might support addr relay on the link include that they connected
358 * to us as a block-relay-only peer or they are a light client.
359 *
360 * This field must correlate with whether m_addr_known has been
361 * initialized.*/
362 std::atomic_bool m_addr_relay_enabled{false};
363 /** Whether a getaddr request to this peer is outstanding. */
364 bool m_getaddr_sent GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false};
365 /** Guards address sending timers. */
366 mutable Mutex m_addr_send_times_mutex;
367 /** Time point to send the next ADDR message to this peer. */
368 std::chrono::microseconds m_next_addr_send GUARDED_BY(m_addr_send_times_mutex){0};
369 /** Time point to possibly re-announce our local address to this peer. */
370 std::chrono::microseconds m_next_local_addr_send GUARDED_BY(m_addr_send_times_mutex){0};
371 /** Whether the peer has signaled support for receiving ADDRv2 (BIP155)
372 * messages, indicating a preference to receive ADDRv2 instead of ADDR ones. */
373 std::atomic_bool m_wants_addrv2{false};
374 /** Whether this peer has already sent us a getaddr message. */
375 bool m_getaddr_recvd GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false};
376 /** Number of addresses that can be processed from this peer. Start at 1 to
377 * permit self-announcement. */
378 double m_addr_token_bucket GUARDED_BY(NetEventsInterface::g_msgproc_mutex){1.0};
379 /** When m_addr_token_bucket was last updated */
380 NodeClock::time_point m_addr_token_timestamp GUARDED_BY(NetEventsInterface::g_msgproc_mutex){NodeClock::now()};
381 /** Total number of addresses that were dropped due to rate limiting. */
382 std::atomic<uint64_t> m_addr_rate_limited{0};
383 /** Total number of addresses that were processed (excludes rate-limited ones). */
384 std::atomic<uint64_t> m_addr_processed{0};
385 386 /** Whether we've sent this peer a getheaders in response to an inv prior to initial-headers-sync completing */
387 bool m_inv_triggered_getheaders_before_sync GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false};
388 389 /** Protects m_getdata_requests **/
390 Mutex m_getdata_requests_mutex;
391 /** Work queue of items requested by this peer **/
392 std::deque<CInv> m_getdata_requests GUARDED_BY(m_getdata_requests_mutex);
393 394 /** Time of the last getheaders message to this peer */
395 NodeClock::time_point m_last_getheaders_timestamp GUARDED_BY(NetEventsInterface::g_msgproc_mutex){};
396 397 /** Protects m_headers_sync **/
398 Mutex m_headers_sync_mutex;
399 /** Headers-sync state for this peer (eg for initial sync, or syncing large
400 * reorgs) **/
401 std::unique_ptr<HeadersSyncState> m_headers_sync PT_GUARDED_BY(m_headers_sync_mutex) GUARDED_BY(m_headers_sync_mutex) {};
402 403 /** Whether we've sent our peer a sendheaders message. **/
404 std::atomic<bool> m_sent_sendheaders{false};
405 406 /** When to potentially disconnect peer for stalling headers download */
407 std::chrono::microseconds m_headers_sync_timeout GUARDED_BY(NetEventsInterface::g_msgproc_mutex){0us};
408 409 /** Whether this peer wants invs or headers (when possible) for block announcements */
410 bool m_prefers_headers GUARDED_BY(NetEventsInterface::g_msgproc_mutex){false};
411 412 /** Time offset computed during the version handshake based on the
413 * timestamp the peer sent in the version message. */
414 std::atomic<std::chrono::seconds> m_time_offset{0s};
415 416 explicit Peer(NodeId id, ServiceFlags our_services, bool is_inbound)
417 : m_id{id}
418 , m_our_services{our_services}
419 , m_is_inbound{is_inbound}
420 {}
421 422 private:
423 mutable Mutex m_tx_relay_mutex;
424 425 /** Transaction relay data. May be a nullptr. */
426 std::unique_ptr<TxRelay> m_tx_relay GUARDED_BY(m_tx_relay_mutex);
427 };
428 429 using PeerRef = std::shared_ptr<Peer>;
430 431 /**
432 * Maintain validation-specific state about nodes, protected by cs_main, instead
433 * by CNode's own locks. This simplifies asynchronous operation, where
434 * processing of incoming data is done after the ProcessMessage call returns,
435 * and we're no longer holding the node's locks.
436 */
437 struct CNodeState {
438 //! The best known block we know this peer has announced.
439 const CBlockIndex* pindexBestKnownBlock{nullptr};
440 //! The hash of the last unknown block this peer has announced.
441 uint256 hashLastUnknownBlock{};
442 //! The last full block we both have.
443 const CBlockIndex* pindexLastCommonBlock{nullptr};
444 //! The best header we have sent our peer.
445 const CBlockIndex* pindexBestHeaderSent{nullptr};
446 //! Whether we've started headers synchronization with this peer.
447 bool fSyncStarted{false};
448 //! Since when we're stalling block download progress (in microseconds), or 0.
449 std::chrono::microseconds m_stalling_since{0us};
450 std::list<QueuedBlock> vBlocksInFlight;
451 //! When the first entry in vBlocksInFlight started downloading. Don't care when vBlocksInFlight is empty.
452 std::chrono::microseconds m_downloading_since{0us};
453 //! Whether we consider this a preferred download peer.
454 bool fPreferredDownload{false};
455 /** Whether this peer wants invs or cmpctblocks (when possible) for block announcements. */
456 bool m_requested_hb_cmpctblocks{false};
457 /** Whether this peer will send us cmpctblocks if we request them. */
458 bool m_provides_cmpctblocks{false};
459 460 /** State used to enforce CHAIN_SYNC_TIMEOUT and EXTRA_PEER_CHECK_INTERVAL logic.
461 *
462 * Both are only in effect for outbound, non-manual, non-protected connections.
463 * Any peer protected (m_protect = true) is not chosen for eviction. A peer is
464 * marked as protected if all of these are true:
465 * - its connection type is IsBlockOnlyConn() == false
466 * - it gave us a valid connecting header
467 * - we haven't reached MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT yet
468 * - its chain tip has at least as much work as ours
469 *
470 * CHAIN_SYNC_TIMEOUT: if a peer's best known block has less work than our tip,
471 * set a timeout CHAIN_SYNC_TIMEOUT in the future:
472 * - If at timeout their best known block now has more work than our tip
473 * when the timeout was set, then either reset the timeout or clear it
474 * (after comparing against our current tip's work)
475 * - If at timeout their best known block still has less work than our
476 * tip did when the timeout was set, then send a getheaders message,
477 * and set a shorter timeout, HEADERS_RESPONSE_TIME seconds in future.
478 * If their best known block is still behind when that new timeout is
479 * reached, disconnect.
480 *
481 * EXTRA_PEER_CHECK_INTERVAL: after each interval, if we have too many outbound peers,
482 * drop the outbound one that least recently announced us a new block.
483 */
484 struct ChainSyncTimeoutState {
485 //! A timeout used for checking whether our peer has sufficiently synced
486 std::chrono::seconds m_timeout{0s};
487 //! A header with the work we require on our peer's chain
488 const CBlockIndex* m_work_header{nullptr};
489 //! After timeout is reached, set to true after sending getheaders
490 bool m_sent_getheaders{false};
491 //! Whether this peer is protected from disconnection due to a bad/slow chain
492 bool m_protect{false};
493 };
494 495 ChainSyncTimeoutState m_chain_sync;
496 497 //! Time of last new block announcement
498 int64_t m_last_block_announcement{0};
499 };
500 501 class PeerManagerImpl final : public PeerManager
502 {
503 public:
504 PeerManagerImpl(CConnman& connman, AddrMan& addrman,
505 BanMan* banman, ChainstateManager& chainman,
506 CTxMemPool& pool, node::Warnings& warnings, Options opts);
507 508 /** Overridden from CValidationInterface. */
509 void ActiveTipChange(const CBlockIndex& new_tip, bool) override
510 EXCLUSIVE_LOCKS_REQUIRED(!m_tx_download_mutex);
511 void BlockConnected(const ChainstateRole& role, const std::shared_ptr<const CBlock>& pblock, const CBlockIndex* pindexConnected) override
512 EXCLUSIVE_LOCKS_REQUIRED(!m_tx_download_mutex);
513 void BlockDisconnected(const std::shared_ptr<const CBlock> &block, const CBlockIndex* pindex) override
514 EXCLUSIVE_LOCKS_REQUIRED(!m_tx_download_mutex);
515 void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) override
516 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
517 void BlockChecked(const std::shared_ptr<const CBlock>& block, const BlockValidationState& state) override
518 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
519 void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& pblock) override
520 EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex);
521 522 /** Implement NetEventsInterface */
523 void InitializeNode(const CNode& node, ServiceFlags our_services) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_tx_download_mutex);
524 void FinalizeNode(const CNode& node) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_headers_presync_mutex, !m_tx_download_mutex);
525 bool HasAllDesirableServiceFlags(ServiceFlags services) const override;
526 bool ProcessMessages(CNode& node, std::atomic<bool>& interrupt) override
527 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_most_recent_block_mutex, !m_headers_presync_mutex, g_msgproc_mutex, !m_tx_download_mutex);
528 bool SendMessages(CNode& node) override
529 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_most_recent_block_mutex, g_msgproc_mutex, !m_tx_download_mutex);
530 531 /** Implement PeerManager */
532 void StartScheduledTasks(CScheduler& scheduler) override;
533 void CheckForStaleTipAndEvictPeers() override;
534 util::Expected<void, std::string> FetchBlock(NodeId peer_id, const CBlockIndex& block_index) override
535 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
536 bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
537 std::vector<node::TxOrphanage::OrphanInfo> GetOrphanTransactions() override EXCLUSIVE_LOCKS_REQUIRED(!m_tx_download_mutex);
538 PeerManagerInfo GetInfo() const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
539 std::vector<PrivateBroadcast::TxBroadcastInfo> GetPrivateBroadcastInfo() const override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
540 std::vector<CTransactionRef> AbortPrivateBroadcast(const uint256& id) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
541 void SendPings() override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
542 void InitiateTxBroadcastToAll(const Txid& txid, const Wtxid& wtxid) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
543 node::TransactionError InitiateTxBroadcastPrivate(const CTransactionRef& tx) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
544 void SetBestBlock(int height, std::chrono::seconds time) override
545 {
546 m_best_height = height;
547 m_best_block_time = time;
548 };
549 void UnitTestMisbehaving(NodeId peer_id) override EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex) { Misbehaving(*Assert(GetPeerRef(peer_id)), ""); };
550 void UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds) override;
551 ServiceFlags GetDesirableServiceFlags(ServiceFlags services) const override;
552 553 private:
554 void ProcessMessage(Peer& peer, CNode& pfrom, const std::string& msg_type, DataStream& vRecv, NodeClock::time_point time_received,
555 const std::atomic<bool>& interruptMsgProc)
556 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_most_recent_block_mutex, !m_headers_presync_mutex, g_msgproc_mutex, !m_tx_download_mutex);
557 558 /** Consider evicting an outbound peer based on the amount of time they've been behind our tip */
559 void ConsiderEviction(CNode& pto, Peer& peer, std::chrono::seconds time_in_seconds) EXCLUSIVE_LOCKS_REQUIRED(cs_main, g_msgproc_mutex);
560 561 /** If we have extra outbound peers, try to disconnect the one with the oldest block announcement */
562 void EvictExtraOutboundPeers(NodeClock::time_point now) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
563 564 /** Retrieve unbroadcast transactions from the mempool and reattempt sending to peers */
565 void ReattemptInitialBroadcast(CScheduler& scheduler) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
566 567 /** Rebroadcast stale private transactions (already broadcast but not received back from the network). */
568 void ReattemptPrivateBroadcast(CScheduler& scheduler);
569 570 /** Get a shared pointer to the Peer object.
571 * May return an empty shared_ptr if the Peer object can't be found. */
572 PeerRef GetPeerRef(NodeId id) const EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
573 574 /** Get a shared pointer to the Peer object and remove it from m_peer_map.
575 * May return an empty shared_ptr if the Peer object can't be found. */
576 PeerRef RemovePeer(NodeId id) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
577 578 /// Get all existing peers in m_peer_map.
579 std::vector<PeerRef> GetAllPeers() const EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
580 581 /** Mark a peer as misbehaving, which will cause it to be disconnected and its
582 * address discouraged. */
583 void Misbehaving(Peer& peer, const std::string& message);
584 585 /**
586 * Potentially mark a node discouraged based on the contents of a BlockValidationState object
587 *
588 * @param[in] via_compact_block this bool is passed in because net_processing should
589 * punish peers differently depending on whether the data was provided in a compact
590 * block message or not. If the compact block had a valid header, but contained invalid
591 * txs, the peer should not be punished. See BIP 152.
592 */
593 void MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& state,
594 bool via_compact_block, const std::string& message = "")
595 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex);
596 597 /** Maybe disconnect a peer and discourage future connections from its address.
598 *
599 * @param[in] pnode The node to check.
600 * @param[in] peer The peer object to check.
601 * @return True if the peer was marked for disconnection in this function
602 */
603 bool MaybeDiscourageAndDisconnect(CNode& pnode, Peer& peer);
604 605 /** Handle a transaction whose result was not MempoolAcceptResult::ResultType::VALID.
606 * @param[in] first_time_failure Whether we should consider inserting into vExtraTxnForCompact, adding
607 * a new orphan to resolve, or looking for a package to submit.
608 * Set to true for transactions just received over p2p.
609 * Set to false if the tx has already been rejected before,
610 * e.g. is already in the orphanage, to avoid adding duplicate entries.
611 * Updates m_txrequest, m_lazy_recent_rejects, m_lazy_recent_rejects_reconsiderable, m_orphanage, and vExtraTxnForCompact.
612 *
613 * @returns a PackageToValidate if this transaction has a reconsiderable failure and an eligible package was found,
614 * or std::nullopt otherwise.
615 */
616 std::optional<node::PackageToValidate> ProcessInvalidTx(NodeId nodeid, const CTransactionRef& tx, const TxValidationState& result,
617 bool first_time_failure)
618 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, m_tx_download_mutex);
619 620 /** Handle a transaction whose result was MempoolAcceptResult::ResultType::VALID.
621 * Updates m_txrequest, m_orphanage, and vExtraTxnForCompact. Also queues the tx for relay. */
622 void ProcessValidTx(NodeId nodeid, const CTransactionRef& tx, const std::list<CTransactionRef>& replaced_transactions)
623 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, m_tx_download_mutex);
624 625 /** Handle the results of package validation: calls ProcessValidTx and ProcessInvalidTx for
626 * individual transactions, and caches rejection for the package as a group.
627 */
628 void ProcessPackageResult(const node::PackageToValidate& package_to_validate, const PackageMempoolAcceptResult& package_result)
629 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, m_tx_download_mutex);
630 631 /**
632 * Reconsider orphan transactions after a parent has been accepted to the mempool.
633 *
634 * @peer[in] peer The peer whose orphan transactions we will reconsider. Generally only
635 * one orphan will be reconsidered on each call of this function. If an
636 * accepted orphan has orphaned children, those will need to be
637 * reconsidered, creating more work, possibly for other peers.
638 * @return True if meaningful work was done (an orphan was accepted/rejected).
639 * If no meaningful work was done, then the work set for this peer
640 * will be empty.
641 */
642 bool ProcessOrphanTx(Peer& peer)
643 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex, !m_tx_download_mutex);
644 645 /** Process a single headers message from a peer.
646 *
647 * @param[in] pfrom CNode of the peer
648 * @param[in] peer The peer sending us the headers
649 * @param[in] headers The headers received. Note that this may be modified within ProcessHeadersMessage.
650 * @param[in] via_compact_block Whether this header came in via compact block handling.
651 */
652 void ProcessHeadersMessage(CNode& pfrom, Peer& peer,
653 std::vector<CBlockHeader>&& headers,
654 bool via_compact_block)
655 EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, !m_headers_presync_mutex, g_msgproc_mutex);
656 /** Various helpers for headers processing, invoked by ProcessHeadersMessage() */
657 /** Return true if headers are continuous and have valid proof-of-work (DoS points assigned on failure) */
658 bool CheckHeadersPoW(const std::vector<CBlockHeader>& headers, Peer& peer);
659 /** Calculate an anti-DoS work threshold for headers chains */
660 arith_uint256 GetAntiDoSWorkThreshold();
661 /** Deal with state tracking and headers sync for peers that send
662 * non-connecting headers (this can happen due to BIP 130 headers
663 * announcements for blocks interacting with the 2hr (MAX_FUTURE_BLOCK_TIME) rule). */
664 void HandleUnconnectingHeaders(CNode& pfrom, Peer& peer, const std::vector<CBlockHeader>& headers) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
665 /** Return true if the headers connect to each other, false otherwise */
666 bool CheckHeadersAreContinuous(const std::vector<CBlockHeader>& headers) const;
667 /** Try to continue a low-work headers sync that has already begun.
668 * Assumes the caller has already verified the headers connect, and has
669 * checked that each header satisfies the proof-of-work target included in
670 * the header.
671 * @param[in] peer The peer we're syncing with.
672 * @param[in] pfrom CNode of the peer
673 * @param[in,out] headers The headers to be processed.
674 * @return True if the passed in headers were successfully processed
675 * as the continuation of a low-work headers sync in progress;
676 * false otherwise.
677 * If false, the passed in headers will be returned back to
678 * the caller.
679 * If true, the returned headers may be empty, indicating
680 * there is no more work for the caller to do; or the headers
681 * may be populated with entries that have passed anti-DoS
682 * checks (and therefore may be validated for block index
683 * acceptance by the caller).
684 */
685 bool IsContinuationOfLowWorkHeadersSync(Peer& peer, CNode& pfrom,
686 std::vector<CBlockHeader>& headers)
687 EXCLUSIVE_LOCKS_REQUIRED(peer.m_headers_sync_mutex, !m_headers_presync_mutex, g_msgproc_mutex);
688 /** Check work on a headers chain to be processed, and if insufficient,
689 * initiate our anti-DoS headers sync mechanism.
690 *
691 * @param[in] peer The peer whose headers we're processing.
692 * @param[in] pfrom CNode of the peer
693 * @param[in] chain_start_header Where these headers connect in our index.
694 * @param[in,out] headers The headers to be processed.
695 *
696 * @return True if chain was low work (headers will be empty after
697 * calling); false otherwise.
698 */
699 bool TryLowWorkHeadersSync(Peer& peer, CNode& pfrom,
700 const CBlockIndex& chain_start_header,
701 std::vector<CBlockHeader>& headers)
702 EXCLUSIVE_LOCKS_REQUIRED(!peer.m_headers_sync_mutex, !m_peer_mutex, !m_headers_presync_mutex, g_msgproc_mutex);
703 704 /** Return true if the given header is an ancestor of
705 * m_chainman.m_best_header or our current tip */
706 bool IsAncestorOfBestHeaderOrTip(const CBlockIndex* header) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
707 708 /** Request further headers from this peer with a given locator.
709 * We don't issue a getheaders message if we have a recent one outstanding.
710 * This returns true if a getheaders is actually sent, and false otherwise.
711 */
712 bool MaybeSendGetHeaders(CNode& pfrom, const CBlockLocator& locator, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
713 /** Potentially fetch blocks from this peer upon receipt of a new headers tip */
714 void HeadersDirectFetchBlocks(CNode& pfrom, const Peer& peer, const CBlockIndex& last_header);
715 /** Update peer state based on received headers message */
716 void UpdatePeerStateForReceivedHeaders(CNode& pfrom, Peer& peer, const CBlockIndex& last_header, bool received_new_header, bool may_have_more_headers)
717 EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
718 719 void SendBlockTransactions(CNode& pfrom, Peer& peer, const CBlock& block, const BlockTransactionsRequest& req);
720 721 /** Send a message to a peer */
722 void PushMessage(CNode& node, CSerializedNetMsg&& msg) const { m_connman.PushMessage(&node, std::move(msg)); }
723 template <typename... Args>
724 void MakeAndPushMessage(CNode& node, std::string msg_type, Args&&... args) const
725 {
726 m_connman.PushMessage(&node, NetMsg::Make(std::move(msg_type), std::forward<Args>(args)...));
727 }
728 template <typename... Args>
729 void MakeAndPushFeature(CNode& node, std::string_view feature_id, Args&&... args) const
730 {
731 if (!Assume(feature_id.size() >= 4 && feature_id.size() <= MAX_FEATUREID_LENGTH)) return;
732 std::vector<unsigned char> feature_data;
733 VectorWriter{feature_data, 0, std::forward<Args>(args)...};
734 if (!Assume(feature_data.size() <= MAX_FEATUREDATA_LENGTH)) return;
735 MakeAndPushMessage(node, NetMsgType::FEATURE, feature_id, std::move(feature_data));
736 }
737 738 /** Send a version message to a peer */
739 void PushNodeVersion(CNode& pnode, const Peer& peer);
740 741 /** Send a ping message every PING_INTERVAL or if requested via RPC (peer.m_ping_queued is true).
742 * May mark the peer to be disconnected if a ping has timed out.
743 * We use mockable time for ping timeouts, so setmocktime may cause pings
744 * to time out. */
745 void MaybeSendPing(CNode& node_to, Peer& peer, NodeClock::time_point now);
746 747 /** Send `addr` messages on a regular schedule. */
748 void MaybeSendAddr(CNode& node, Peer& peer, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
749 750 /** Send a single `sendheaders` message, after we have completed headers sync with a peer. */
751 void MaybeSendSendHeaders(CNode& node, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
752 753 /** Relay (gossip) an address to a few randomly chosen nodes.
754 *
755 * @param[in] originator The id of the peer that sent us the address. We don't want to relay it back.
756 * @param[in] addr Address to relay.
757 * @param[in] fReachable Whether the address' network is reachable. We relay unreachable
758 * addresses less.
759 */
760 void RelayAddress(NodeId originator, const CAddress& addr, bool fReachable) EXCLUSIVE_LOCKS_REQUIRED(!m_peer_mutex, g_msgproc_mutex);
761 762 /** Send `feefilter` message. */
763 void MaybeSendFeefilter(CNode& node, Peer& peer, std::chrono::microseconds current_time) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
764 765 FastRandomContext m_rng GUARDED_BY(NetEventsInterface::g_msgproc_mutex);
766 767 FeeFilterRounder m_fee_filter_rounder GUARDED_BY(NetEventsInterface::g_msgproc_mutex);
768 769 const CChainParams& m_chainparams;
770 CConnman& m_connman;
771 AddrMan& m_addrman;
772 /** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */
773 BanMan* const m_banman;
774 ChainstateManager& m_chainman;
775 CTxMemPool& m_mempool;
776 777 /** Synchronizes tx download including TxRequestTracker, rejection filters, and TxOrphanage.
778 * Lock invariants:
779 * - A txhash (txid or wtxid) in m_txrequest is not also in m_orphanage.
780 * - A txhash (txid or wtxid) in m_txrequest is not also in m_lazy_recent_rejects.
781 * - A txhash (txid or wtxid) in m_txrequest is not also in m_lazy_recent_rejects_reconsiderable.
782 * - A txhash (txid or wtxid) in m_txrequest is not also in m_lazy_recent_confirmed_transactions.
783 * - Each data structure's limits hold (m_orphanage max size, m_txrequest per-peer limits, etc).
784 */
785 Mutex m_tx_download_mutex ACQUIRED_BEFORE(m_mempool.cs);
786 node::TxDownloadManager m_txdownloadman GUARDED_BY(m_tx_download_mutex);
787 788 std::unique_ptr<TxReconciliationTracker> m_txreconciliation;
789 790 /** The height of the best chain */
791 std::atomic<int> m_best_height{-1};
792 /** The time of the best chain tip block */
793 std::atomic<std::chrono::seconds> m_best_block_time{0s};
794 795 /** Next time to check for stale tip */
796 std::chrono::seconds m_stale_tip_check_time GUARDED_BY(cs_main){0s};
797 798 node::Warnings& m_warnings;
799 TimeOffsets m_outbound_time_offsets{m_warnings};
800 801 const Options m_opts;
802 803 bool RejectIncomingTxs(const CNode& peer) const;
804 805 /** Whether we've completed initial sync yet, for determining when to turn
806 * on extra block-relay-only peers. */
807 bool m_initial_sync_finished GUARDED_BY(cs_main){false};
808 809 /** Protects m_peer_map. This mutex must not be locked while holding a lock
810 * on any of the mutexes inside a Peer object. */
811 mutable Mutex m_peer_mutex;
812 /**
813 * Map of all Peer objects, keyed by peer id. This map is protected
814 * by the m_peer_mutex. Once a shared pointer reference is
815 * taken, the lock may be released. Individual fields are protected by
816 * their own locks.
817 */
818 std::map<NodeId, PeerRef> m_peer_map GUARDED_BY(m_peer_mutex);
819 820 /** Map maintaining per-node state. */
821 std::map<NodeId, CNodeState> m_node_states GUARDED_BY(cs_main);
822 823 /** Get a pointer to a const CNodeState, used when not mutating the CNodeState object. */
824 const CNodeState* State(NodeId pnode) const EXCLUSIVE_LOCKS_REQUIRED(cs_main);
825 /** Get a pointer to a mutable CNodeState. */
826 CNodeState* State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
827 828 uint32_t GetFetchFlags(const Peer& peer) const;
829 830 std::map<uint64_t, std::chrono::microseconds> m_next_inv_to_inbounds_per_network_key GUARDED_BY(g_msgproc_mutex);
831 832 /** Number of nodes with fSyncStarted. */
833 int nSyncStarted GUARDED_BY(cs_main) = 0;
834 835 /** Hash of the last block we received via INV */
836 uint256 m_last_block_inv_triggering_headers_sync GUARDED_BY(g_msgproc_mutex){};
837 838 /**
839 * Sources of received blocks, saved to be able punish them when processing
840 * happens afterwards.
841 * Set mapBlockSource[hash].second to false if the node should not be
842 * punished if the block is invalid.
843 */
844 std::map<uint256, std::pair<NodeId, bool>> mapBlockSource GUARDED_BY(cs_main);
845 846 /** Number of peers with wtxid relay. */
847 std::atomic<int> m_wtxid_relay_peers{0};
848 849 /** Number of outbound peers with m_chain_sync.m_protect. */
850 int m_outbound_peers_with_protect_from_disconnect GUARDED_BY(cs_main) = 0;
851 852 /** Number of preferable block download peers. */
853 int m_num_preferred_download_peers GUARDED_BY(cs_main){0};
854 855 /** Stalling timeout for blocks in IBD */
856 std::atomic<std::chrono::seconds> m_block_stalling_timeout{BLOCK_STALLING_TIMEOUT_DEFAULT};
857 858 /**
859 * For sending `inv`s to inbound peers, we use a single (exponentially
860 * distributed) timer for all peers with the same network key. If we used a separate timer for each
861 * peer, a spy node could make multiple inbound connections to us to
862 * accurately determine when we received a transaction (and potentially
863 * determine the transaction's origin). Each network key has its own timer
864 * to make fingerprinting harder. */
865 std::chrono::microseconds NextInvToInbounds(std::chrono::microseconds now,
866 std::chrono::seconds average_interval,
867 uint64_t network_key) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
868 869 870 // All of the following cache a recent block, and are protected by m_most_recent_block_mutex
871 Mutex m_most_recent_block_mutex;
872 std::shared_ptr<const CBlock> m_most_recent_block GUARDED_BY(m_most_recent_block_mutex);
873 std::shared_ptr<const CBlockHeaderAndShortTxIDs> m_most_recent_compact_block GUARDED_BY(m_most_recent_block_mutex);
874 uint256 m_most_recent_block_hash GUARDED_BY(m_most_recent_block_mutex);
875 std::unique_ptr<const std::map<GenTxid, CTransactionRef>> m_most_recent_block_txs GUARDED_BY(m_most_recent_block_mutex);
876 877 // Data about the low-work headers synchronization, aggregated from all peers' HeadersSyncStates.
878 /** Mutex guarding the other m_headers_presync_* variables. */
879 Mutex m_headers_presync_mutex;
880 /** A type to represent statistics about a peer's low-work headers sync.
881 *
882 * - The first field is the total verified amount of work in that synchronization.
883 * - The second is:
884 * - nullopt: the sync is in REDOWNLOAD phase (phase 2).
885 * - {height, timestamp}: the sync has the specified tip height and block timestamp (phase 1).
886 */
887 using HeadersPresyncStats = std::pair<arith_uint256, std::optional<std::pair<int64_t, uint32_t>>>;
888 /** Statistics for all peers in low-work headers sync. */
889 std::map<NodeId, HeadersPresyncStats> m_headers_presync_stats GUARDED_BY(m_headers_presync_mutex) {};
890 /** The peer with the most-work entry in m_headers_presync_stats. */
891 NodeId m_headers_presync_bestpeer GUARDED_BY(m_headers_presync_mutex) {-1};
892 /** The m_headers_presync_stats improved, and needs signalling. */
893 std::atomic_bool m_headers_presync_should_signal{false};
894 895 /** Height of the highest block announced using BIP 152 high-bandwidth mode. */
896 int m_highest_fast_announce GUARDED_BY(::cs_main){0};
897 898 /** Have we requested this block from a peer */
899 bool IsBlockRequested(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
900 901 /** Have we requested this block from an outbound peer */
902 bool IsBlockRequestedFromOutbound(const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main, !m_peer_mutex);
903 904 /** Remove this block from our tracked requested blocks. Called if:
905 * - the block has been received from a peer
906 * - the request for the block has timed out
907 * If "from_peer" is specified, then only remove the block if it is in
908 * flight from that peer (to avoid one peer's network traffic from
909 * affecting another's state).
910 */
911 void RemoveBlockRequest(const uint256& hash, std::optional<NodeId> from_peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
912 913 /* Mark a block as in flight
914 * Returns false, still setting pit, if the block was already in flight from the same peer
915 * pit will only be valid as long as the same cs_main lock is being held
916 */
917 bool BlockRequested(NodeId nodeid, const CBlockIndex& block, std::list<QueuedBlock>::iterator** pit = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
918 919 bool TipMayBeStale() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
920 921 /** Update pindexLastCommonBlock and add not-in-flight missing successors to vBlocks, until it has
922 * at most count entries.
923 */
924 void FindNextBlocksToDownload(const Peer& peer, unsigned int count, std::vector<const CBlockIndex*>& vBlocks, NodeId& nodeStaller) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
925 926 /** Request blocks for the background chainstate, if one is in use. */
927 void TryDownloadingHistoricalBlocks(const Peer& peer, unsigned int count, std::vector<const CBlockIndex*>& vBlocks, const CBlockIndex* from_tip, const CBlockIndex* target_block) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
928 929 /**
930 * \brief Find next blocks to download from a peer after a starting block.
931 *
932 * \param vBlocks Vector of blocks to download which will be appended to.
933 * \param peer Peer which blocks will be downloaded from.
934 * \param state Pointer to the state of the peer.
935 * \param pindexWalk Pointer to the starting block to add to vBlocks.
936 * \param count Maximum number of blocks to allow in vBlocks. No more
937 * blocks will be added if it reaches this size.
938 * \param nWindowEnd Maximum height of blocks to allow in vBlocks. No
939 * blocks will be added above this height.
940 * \param activeChain Optional pointer to a chain to compare against. If
941 * provided, any next blocks which are already contained
942 * in this chain will not be appended to vBlocks, but
943 * instead will be used to update the
944 * state->pindexLastCommonBlock pointer.
945 * \param nodeStaller Optional pointer to a NodeId variable that will receive
946 * the ID of another peer that might be causing this peer
947 * to stall. This is set to the ID of the peer which
948 * first requested the first in-flight block in the
949 * download window. It is only set if vBlocks is empty at
950 * the end of this function call and if increasing
951 * nWindowEnd by 1 would cause it to be non-empty (which
952 * indicates the download might be stalled because every
953 * block in the window is in flight and no other peer is
954 * trying to download the next block).
955 */
956 void FindNextBlocks(std::vector<const CBlockIndex*>& 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);
957 958 /* Multimap used to preserve insertion order */
959 typedef std::multimap<uint256, std::pair<NodeId, std::list<QueuedBlock>::iterator>> BlockDownloadMap;
960 BlockDownloadMap mapBlocksInFlight GUARDED_BY(cs_main);
961 962 /** When our tip was last updated. */
963 std::atomic<std::chrono::seconds> m_last_tip_update{0s};
964 965 /** Determine whether or not a peer can request a transaction, and return it (or nullptr if not found or not allowed). */
966 CTransactionRef FindTxForGetData(const Peer::TxRelay& tx_relay, const GenTxid& gtxid)
967 EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex, !tx_relay.m_tx_inventory_mutex);
968 969 void ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic<bool>& interruptMsgProc)
970 EXCLUSIVE_LOCKS_REQUIRED(!m_most_recent_block_mutex, peer.m_getdata_requests_mutex, NetEventsInterface::g_msgproc_mutex)
971 LOCKS_EXCLUDED(::cs_main);
972 973 /** Process a new block. Perform any post-processing housekeeping */
974 void ProcessBlock(CNode& node, const std::shared_ptr<const CBlock>& block, bool force_processing, bool min_pow_checked);
975 976 /** Process compact block txns */
977 void ProcessCompactBlockTxns(CNode& pfrom, Peer& peer, const BlockTransactions& block_transactions)
978 EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex, !m_most_recent_block_mutex);
979 980 /**
981 * Schedule an INV for a transaction to be sent to the given peer (via `PushMessage()`).
982 * The transaction is picked from the list of transactions for private broadcast.
983 * It is assumed that the connection to the peer is `ConnectionType::PRIVATE_BROADCAST`.
984 * Avoid calling this for other peers since it will degrade privacy.
985 */
986 void PushPrivateBroadcastTx(CNode& node) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex, !m_most_recent_block_mutex);
987 988 /**
989 * When a peer sends us a valid block, instruct it to announce blocks to us
990 * using CMPCTBLOCK if possible by adding its nodeid to the end of
991 * lNodesAnnouncingHeaderAndIDs, and keeping that list under a certain size by
992 * removing the first element if necessary.
993 */
994 void MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(cs_main, !m_peer_mutex);
995 996 /** Stack of nodes which we have set to announce using compact blocks */
997 std::list<NodeId> lNodesAnnouncingHeaderAndIDs GUARDED_BY(cs_main);
998 999 /** Number of peers from which we're downloading blocks. */
1000 int m_peers_downloading_from GUARDED_BY(cs_main) = 0;
1001 1002 void AddToCompactExtraTransactions(const CTransactionRef& tx) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
1003 1004 /** Orphan/conflicted/etc transactions that are kept for compact block reconstruction.
1005 * The last -blockreconstructionextratxn/DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN of
1006 * these are kept in a ring buffer */
1007 std::vector<std::pair<Wtxid, CTransactionRef>> vExtraTxnForCompact GUARDED_BY(g_msgproc_mutex);
1008 /** Offset into vExtraTxnForCompact to insert the next tx */
1009 size_t vExtraTxnForCompactIt GUARDED_BY(g_msgproc_mutex) = 0;
1010 1011 /** Check whether the last unknown block a peer advertised is not yet known. */
1012 void ProcessBlockAvailability(NodeId nodeid) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
1013 /** Update tracking information about which blocks a peer is assumed to have. */
1014 void UpdateBlockAvailability(NodeId nodeid, const uint256& hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
1015 bool CanDirectFetch() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
1016 1017 /**
1018 * Estimates the distance, in blocks, between the best-known block and the network chain tip.
1019 * Utilizes the best-block time and the chainparams blocks spacing to approximate it.
1020 */
1021 int64_t ApproximateBestBlockDepth() const;
1022 1023 /**
1024 * To prevent fingerprinting attacks, only send blocks/headers outside of
1025 * the active chain if they are no more than a month older (both in time,
1026 * and in best equivalent proof of work) than the best header chain we know
1027 * about and we fully-validated them at some point.
1028 */
1029 bool BlockRequestAllowed(const CBlockIndex& block_index) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
1030 bool AlreadyHaveBlock(const uint256& block_hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
1031 void ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv& inv)
1032 EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex, !m_most_recent_block_mutex);
1033 1034 /**
1035 * Validation logic for compact filters request handling.
1036 *
1037 * May disconnect from the peer in the case of a bad request.
1038 *
1039 * @param[in] node The node that we received the request from
1040 * @param[in] peer The peer that we received the request from
1041 * @param[in] filter_type The filter type the request is for. Must be basic filters.
1042 * @param[in] start_height The start height for the request
1043 * @param[in] stop_hash The stop_hash for the request
1044 * @param[in] max_height_diff The maximum number of items permitted to request, as specified in BIP 157
1045 * @param[out] stop_index The CBlockIndex for the stop_hash block, if the request can be serviced.
1046 * @param[out] filter_index The filter index, if the request can be serviced.
1047 * @return True if the request can be serviced.
1048 */
1049 bool PrepareBlockFilterRequest(CNode& node, Peer& peer,
1050 BlockFilterType filter_type, uint32_t start_height,
1051 const uint256& stop_hash, uint32_t max_height_diff,
1052 const CBlockIndex*& stop_index,
1053 BlockFilterIndex*& filter_index);
1054 1055 /**
1056 * Handle a cfilters request.
1057 *
1058 * May disconnect from the peer in the case of a bad request.
1059 *
1060 * @param[in] node The node that we received the request from
1061 * @param[in] peer The peer that we received the request from
1062 * @param[in] vRecv The raw message received
1063 */
1064 void ProcessGetCFilters(CNode& node, Peer& peer, DataStream& vRecv);
1065 1066 /**
1067 * Handle a cfheaders request.
1068 *
1069 * May disconnect from the peer in the case of a bad request.
1070 *
1071 * @param[in] node The node that we received the request from
1072 * @param[in] peer The peer that we received the request from
1073 * @param[in] vRecv The raw message received
1074 */
1075 void ProcessGetCFHeaders(CNode& node, Peer& peer, DataStream& vRecv);
1076 1077 /**
1078 * Handle a getcfcheckpt request.
1079 *
1080 * May disconnect from the peer in the case of a bad request.
1081 *
1082 * @param[in] node The node that we received the request from
1083 * @param[in] peer The peer that we received the request from
1084 * @param[in] vRecv The raw message received
1085 */
1086 void ProcessGetCFCheckPt(CNode& node, Peer& peer, DataStream& vRecv);
1087 1088 void ProcessPong(CNode& pfrom, Peer& peer, NodeClock::time_point ping_end, DataStream& vRecv);
1089 1090 /** Checks if address relay is permitted with peer. If needed, initializes
1091 * the m_addr_known bloom filter and sets m_addr_relay_enabled to true.
1092 *
1093 * @return True if address relay is enabled with peer
1094 * False if address relay is disallowed
1095 */
1096 bool SetupAddressRelay(const CNode& node, Peer& peer) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
1097 1098 void ProcessAddrs(std::string_view msg_type, CNode& pfrom, Peer& peer, std::vector<CAddress>&& vAddr, const std::atomic<bool>& interruptMsgProc)
1099 EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex, !m_peer_mutex);
1100 1101 void AddAddressKnown(Peer& peer, const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
1102 void PushAddress(Peer& peer, const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex);
1103 1104 void LogBlockHeader(const CBlockIndex& index, const CNode& peer, bool via_compact_block);
1105 1106 /// The transactions to be broadcast privately.
1107 PrivateBroadcast m_tx_for_private_broadcast;
1108 };
1109 1110 const CNodeState* PeerManagerImpl::State(NodeId pnode) const
1111 {
1112 std::map<NodeId, CNodeState>::const_iterator it = m_node_states.find(pnode);
1113 if (it == m_node_states.end())
1114 return nullptr;
1115 return &it->second;
1116 }
1117 1118 CNodeState* PeerManagerImpl::State(NodeId pnode)
1119 {
1120 return const_cast<CNodeState*>(std::as_const(*this).State(pnode));
1121 }
1122 1123 /**
1124 * Whether the peer supports the address. For example, a peer that does not
1125 * implement BIP155 cannot receive Tor v3 addresses because it requires
1126 * ADDRv2 (BIP155) encoding.
1127 */
1128 static bool IsAddrCompatible(const Peer& peer, const CAddress& addr)
1129 {
1130 return peer.m_wants_addrv2 || addr.IsAddrV1Compatible();
1131 }
1132 1133 void PeerManagerImpl::AddAddressKnown(Peer& peer, const CAddress& addr)
1134 {
1135 assert(peer.m_addr_known);
1136 peer.m_addr_known->insert(addr.GetKey());
1137 }
1138 1139 void PeerManagerImpl::PushAddress(Peer& peer, const CAddress& addr)
1140 {
1141 // Known checking here is only to save space from duplicates.
1142 // Before sending, we'll filter it again for known addresses that were
1143 // added after addresses were pushed.
1144 assert(peer.m_addr_known);
1145 if (addr.IsValid() && !peer.m_addr_known->contains(addr.GetKey()) && IsAddrCompatible(peer, addr)) {
1146 if (peer.m_addrs_to_send.size() >= MAX_ADDR_TO_SEND) {
1147 peer.m_addrs_to_send[m_rng.randrange(peer.m_addrs_to_send.size())] = addr;
1148 } else {
1149 peer.m_addrs_to_send.push_back(addr);
1150 }
1151 }
1152 }
1153 1154 static void AddKnownTx(Peer& peer, const uint256& hash)
1155 {
1156 auto tx_relay = peer.GetTxRelay();
1157 if (!tx_relay) return;
1158 1159 LOCK(tx_relay->m_tx_inventory_mutex);
1160 tx_relay->m_tx_inventory_known_filter.insert(hash);
1161 }
1162 1163 /** Whether this peer can serve us blocks. */
1164 static bool CanServeBlocks(const Peer& peer)
1165 {
1166 return peer.m_their_services & (NODE_NETWORK|NODE_NETWORK_LIMITED);
1167 }
1168 1169 /** Whether this peer can only serve limited recent blocks (e.g. because
1170 * it prunes old blocks) */
1171 static bool IsLimitedPeer(const Peer& peer)
1172 {
1173 return (!(peer.m_their_services & NODE_NETWORK) &&
1174 (peer.m_their_services & NODE_NETWORK_LIMITED));
1175 }
1176 1177 /** Whether this peer can serve us witness data */
1178 static bool CanServeWitnesses(const Peer& peer)
1179 {
1180 return peer.m_their_services & NODE_WITNESS;
1181 }
1182 1183 std::chrono::microseconds PeerManagerImpl::NextInvToInbounds(std::chrono::microseconds now,
1184 std::chrono::seconds average_interval,
1185 uint64_t network_key)
1186 {
1187 auto [it, inserted] = m_next_inv_to_inbounds_per_network_key.try_emplace(network_key, 0us);
1188 auto& timer{it->second};
1189 if (timer < now) {
1190 timer = now + m_rng.rand_exp_duration(average_interval);
1191 }
1192 return timer;
1193 }
1194 1195 bool PeerManagerImpl::IsBlockRequested(const uint256& hash)
1196 {
1197 return mapBlocksInFlight.contains(hash);
1198 }
1199 1200 bool PeerManagerImpl::IsBlockRequestedFromOutbound(const uint256& hash)
1201 {
1202 for (auto range = mapBlocksInFlight.equal_range(hash); range.first != range.second; range.first++) {
1203 auto [nodeid, block_it] = range.first->second;
1204 PeerRef peer{GetPeerRef(nodeid)};
1205 if (peer && !peer->m_is_inbound) return true;
1206 }
1207 1208 return false;
1209 }
1210 1211 void PeerManagerImpl::RemoveBlockRequest(const uint256& hash, std::optional<NodeId> from_peer)
1212 {
1213 auto range = mapBlocksInFlight.equal_range(hash);
1214 if (range.first == range.second) {
1215 // Block was not requested from any peer
1216 return;
1217 }
1218 1219 // We should not have requested too many of this block
1220 Assume(mapBlocksInFlight.count(hash) <= MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK);
1221 1222 while (range.first != range.second) {
1223 const auto& [node_id, list_it]{range.first->second};
1224 1225 if (from_peer && *from_peer != node_id) {
1226 range.first++;
1227 continue;
1228 }
1229 1230 CNodeState& state = *Assert(State(node_id));
1231 1232 if (state.vBlocksInFlight.begin() == list_it) {
1233 // First block on the queue was received, update the start download time for the next one
1234 state.m_downloading_since = std::max(state.m_downloading_since, GetTime<std::chrono::microseconds>());
1235 }
1236 state.vBlocksInFlight.erase(list_it);
1237 1238 if (state.vBlocksInFlight.empty()) {
1239 // Last validated block on the queue for this peer was received.
1240 m_peers_downloading_from--;
1241 }
1242 state.m_stalling_since = 0us;
1243 1244 range.first = mapBlocksInFlight.erase(range.first);
1245 }
1246 }
1247 1248 bool PeerManagerImpl::BlockRequested(NodeId nodeid, const CBlockIndex& block, std::list<QueuedBlock>::iterator** pit)
1249 {
1250 const uint256& hash{block.GetBlockHash()};
1251 1252 CNodeState *state = State(nodeid);
1253 assert(state != nullptr);
1254 1255 Assume(mapBlocksInFlight.count(hash) <= MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK);
1256 1257 // Short-circuit most stuff in case it is from the same node
1258 for (auto range = mapBlocksInFlight.equal_range(hash); range.first != range.second; range.first++) {
1259 if (range.first->second.first == nodeid) {
1260 if (pit) {
1261 *pit = &range.first->second.second;
1262 }
1263 return false;
1264 }
1265 }
1266 1267 // Make sure it's not being fetched already from same peer.
1268 RemoveBlockRequest(hash, nodeid);
1269 1270 std::list<QueuedBlock>::iterator it = state->vBlocksInFlight.insert(state->vBlocksInFlight.end(),
1271 {&block, std::unique_ptr<PartiallyDownloadedBlock>(pit ? new PartiallyDownloadedBlock(&m_mempool) : nullptr)});
1272 if (state->vBlocksInFlight.size() == 1) {
1273 // We're starting a block download (batch) from this peer.
1274 state->m_downloading_since = GetTime<std::chrono::microseconds>();
1275 m_peers_downloading_from++;
1276 }
1277 auto itInFlight = mapBlocksInFlight.insert(std::make_pair(hash, std::make_pair(nodeid, it)));
1278 if (pit) {
1279 *pit = &itInFlight->second.second;
1280 }
1281 return true;
1282 }
1283 1284 void PeerManagerImpl::MaybeSetPeerAsAnnouncingHeaderAndIDs(NodeId nodeid)
1285 {
1286 AssertLockHeld(cs_main);
1287 1288 // When in -blocksonly mode, never request high-bandwidth mode from peers. Our
1289 // mempool will not contain the transactions necessary to reconstruct the
1290 // compact block.
1291 if (m_opts.ignore_incoming_txs) return;
1292 1293 CNodeState* nodestate = State(nodeid);
1294 PeerRef peer{GetPeerRef(nodeid)};
1295 if (!nodestate || !nodestate->m_provides_cmpctblocks) {
1296 // Don't request compact blocks if the peer has not signalled support
1297 return;
1298 }
1299 1300 int num_outbound_hb_peers = 0;
1301 for (std::list<NodeId>::iterator it = lNodesAnnouncingHeaderAndIDs.begin(); it != lNodesAnnouncingHeaderAndIDs.end(); it++) {
1302 if (*it == nodeid) {
1303 lNodesAnnouncingHeaderAndIDs.erase(it);
1304 lNodesAnnouncingHeaderAndIDs.push_back(nodeid);
1305 return;
1306 }
1307 PeerRef peer_ref{GetPeerRef(*it)};
1308 if (peer_ref && !peer_ref->m_is_inbound) ++num_outbound_hb_peers;
1309 }
1310 if (peer && peer->m_is_inbound) {
1311 // If we're adding an inbound HB peer, make sure we're not removing
1312 // our last outbound HB peer in the process.
1313 if (lNodesAnnouncingHeaderAndIDs.size() >= 3 && num_outbound_hb_peers == 1) {
1314 PeerRef remove_peer{GetPeerRef(lNodesAnnouncingHeaderAndIDs.front())};
1315 if (remove_peer && !remove_peer->m_is_inbound) {
1316 // Put the HB outbound peer in the second slot, so that it
1317 // doesn't get removed.
1318 std::swap(lNodesAnnouncingHeaderAndIDs.front(), *std::next(lNodesAnnouncingHeaderAndIDs.begin()));
1319 }
1320 }
1321 }
1322 const bool nodeid_was_appended{m_connman.ForNode(nodeid, [this](CNode* pfrom) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
1323 AssertLockHeld(::cs_main);
1324 MakeAndPushMessage(*pfrom, NetMsgType::SENDCMPCT, /*high_bandwidth=*/true, /*version=*/CMPCTBLOCKS_VERSION);
1325 // save BIP152 bandwidth state: we select peer to be high-bandwidth
1326 pfrom->m_bip152_highbandwidth_to = true;
1327 lNodesAnnouncingHeaderAndIDs.push_back(pfrom->GetId());
1328 return true;
1329 })};
1330 if (nodeid_was_appended && lNodesAnnouncingHeaderAndIDs.size() > 3) {
1331 // As per BIP152, we only get 3 of our peers to announce
1332 // blocks using compact encodings.
1333 m_connman.ForNode(lNodesAnnouncingHeaderAndIDs.front(), [this](CNode* pnodeStop) {
1334 MakeAndPushMessage(*pnodeStop, NetMsgType::SENDCMPCT, /*high_bandwidth=*/false, /*version=*/CMPCTBLOCKS_VERSION);
1335 // save BIP152 bandwidth state: we select peer to be low-bandwidth
1336 pnodeStop->m_bip152_highbandwidth_to = false;
1337 return true;
1338 });
1339 lNodesAnnouncingHeaderAndIDs.pop_front();
1340 }
1341 }
1342 1343 bool PeerManagerImpl::TipMayBeStale()
1344 {
1345 AssertLockHeld(cs_main);
1346 const Consensus::Params& consensusParams = m_chainparams.GetConsensus();
1347 if (m_last_tip_update.load() == 0s) {
1348 m_last_tip_update = GetTime<std::chrono::seconds>();
1349 }
1350 return m_last_tip_update.load() < GetTime<std::chrono::seconds>() - std::chrono::seconds{consensusParams.nPowTargetSpacing * 3} && mapBlocksInFlight.empty();
1351 }
1352 1353 int64_t PeerManagerImpl::ApproximateBestBlockDepth() const
1354 {
1355 return (GetTime<std::chrono::seconds>() - m_best_block_time.load()).count() / m_chainparams.GetConsensus().nPowTargetSpacing;
1356 }
1357 1358 bool PeerManagerImpl::CanDirectFetch()
1359 {
1360 return m_chainman.ActiveChain().Tip()->Time() > NodeClock::now() - m_chainparams.GetConsensus().PowTargetSpacing() * 20;
1361 }
1362 1363 static bool PeerHasHeader(CNodeState *state, const CBlockIndex *pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
1364 {
1365 if (state->pindexBestKnownBlock && pindex == state->pindexBestKnownBlock->GetAncestor(pindex->nHeight))
1366 return true;
1367 if (state->pindexBestHeaderSent && pindex == state->pindexBestHeaderSent->GetAncestor(pindex->nHeight))
1368 return true;
1369 return false;
1370 }
1371 1372 void PeerManagerImpl::ProcessBlockAvailability(NodeId nodeid) {
1373 CNodeState *state = State(nodeid);
1374 assert(state != nullptr);
1375 1376 if (!state->hashLastUnknownBlock.IsNull()) {
1377 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(state->hashLastUnknownBlock);
1378 if (pindex && pindex->nChainWork > 0) {
1379 if (state->pindexBestKnownBlock == nullptr || pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) {
1380 state->pindexBestKnownBlock = pindex;
1381 }
1382 state->hashLastUnknownBlock.SetNull();
1383 }
1384 }
1385 }
1386 1387 void PeerManagerImpl::UpdateBlockAvailability(NodeId nodeid, const uint256 &hash) {
1388 CNodeState *state = State(nodeid);
1389 assert(state != nullptr);
1390 1391 ProcessBlockAvailability(nodeid);
1392 1393 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(hash);
1394 if (pindex && pindex->nChainWork > 0) {
1395 // An actually better block was announced.
1396 if (state->pindexBestKnownBlock == nullptr || pindex->nChainWork >= state->pindexBestKnownBlock->nChainWork) {
1397 state->pindexBestKnownBlock = pindex;
1398 }
1399 } else {
1400 // An unknown block was announced; just assume that the latest one is the best one.
1401 state->hashLastUnknownBlock = hash;
1402 }
1403 }
1404 1405 // Logic for calculating which blocks to download from a given peer, given our current tip.
1406 void PeerManagerImpl::FindNextBlocksToDownload(const Peer& peer, unsigned int count, std::vector<const CBlockIndex*>& vBlocks, NodeId& nodeStaller)
1407 {
1408 if (count == 0)
1409 return;
1410 1411 vBlocks.reserve(vBlocks.size() + count);
1412 CNodeState *state = State(peer.m_id);
1413 assert(state != nullptr);
1414 1415 // Make sure pindexBestKnownBlock is up to date, we'll need it.
1416 ProcessBlockAvailability(peer.m_id);
1417 1418 if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->nChainWork < m_chainman.ActiveChain().Tip()->nChainWork || state->pindexBestKnownBlock->nChainWork < m_chainman.MinimumChainWork()) {
1419 // This peer has nothing interesting.
1420 return;
1421 }
1422 1423 // When syncing with AssumeUtxo and the snapshot has not yet been validated,
1424 // abort downloading blocks from peers that don't have the snapshot block in their best chain.
1425 // We can't reorg to this chain due to missing undo data until validation completes,
1426 // so downloading blocks from it would be futile.
1427 const CBlockIndex* snap_base{m_chainman.CurrentChainstate().SnapshotBase()};
1428 if (snap_base && m_chainman.CurrentChainstate().m_assumeutxo == Assumeutxo::UNVALIDATED &&
1429 state->pindexBestKnownBlock->GetAncestor(snap_base->nHeight) != snap_base) {
1430 LogDebug(BCLog::NET, "Not downloading blocks from peer=%d, which doesn't have the snapshot block in its best chain.\n", peer.m_id);
1431 return;
1432 }
1433 1434 // Determine the forking point between the peer's chain and our chain:
1435 // pindexLastCommonBlock is required to be an ancestor of pindexBestKnownBlock, and will be used as a starting point.
1436 // It is being set to the fork point between the peer's best known block and the current tip, unless it is already set to
1437 // an ancestor with more work than the fork point.
1438 auto fork_point = LastCommonAncestor(state->pindexBestKnownBlock, m_chainman.ActiveTip());
1439 if (state->pindexLastCommonBlock == nullptr ||
1440 fork_point->nChainWork > state->pindexLastCommonBlock->nChainWork ||
1441 state->pindexBestKnownBlock->GetAncestor(state->pindexLastCommonBlock->nHeight) != state->pindexLastCommonBlock) {
1442 state->pindexLastCommonBlock = fork_point;
1443 }
1444 if (state->pindexLastCommonBlock == state->pindexBestKnownBlock)
1445 return;
1446 1447 const CBlockIndex *pindexWalk = state->pindexLastCommonBlock;
1448 // Never fetch further than the best block we know the peer has, or more than BLOCK_DOWNLOAD_WINDOW + 1 beyond the last
1449 // linked block we have in common with this peer. The +1 is so we can detect stalling, namely if we would be able to
1450 // download that next block if the window were 1 larger.
1451 int nWindowEnd = state->pindexLastCommonBlock->nHeight + BLOCK_DOWNLOAD_WINDOW;
1452 1453 FindNextBlocks(vBlocks, peer, state, pindexWalk, count, nWindowEnd, &m_chainman.ActiveChain(), &nodeStaller);
1454 }
1455 1456 void PeerManagerImpl::TryDownloadingHistoricalBlocks(const Peer& peer, unsigned int count, std::vector<const CBlockIndex*>& vBlocks, const CBlockIndex *from_tip, const CBlockIndex* target_block)
1457 {
1458 Assert(from_tip);
1459 Assert(target_block);
1460 1461 if (vBlocks.size() >= count) {
1462 return;
1463 }
1464 1465 vBlocks.reserve(count);
1466 CNodeState *state = Assert(State(peer.m_id));
1467 1468 if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->GetAncestor(target_block->nHeight) != target_block) {
1469 // This peer can't provide us the complete series of blocks leading up to the
1470 // assumeutxo snapshot base.
1471 //
1472 // Presumably this peer's chain has less work than our ActiveChain()'s tip, or else we
1473 // will eventually crash when we try to reorg to it. Let other logic
1474 // deal with whether we disconnect this peer.
1475 //
1476 // TODO at some point in the future, we might choose to request what blocks
1477 // this peer does have from the historical chain, despite it not having a
1478 // complete history beneath the snapshot base.
1479 return;
1480 }
1481 1482 FindNextBlocks(vBlocks, peer, state, from_tip, count, std::min<int>(from_tip->nHeight + BLOCK_DOWNLOAD_WINDOW, target_block->nHeight));
1483 }
1484 1485 void PeerManagerImpl::FindNextBlocks(std::vector<const CBlockIndex*>& vBlocks, const Peer& peer, CNodeState *state, const CBlockIndex *pindexWalk, unsigned int count, int nWindowEnd, const CChain* activeChain, NodeId* nodeStaller)
1486 {
1487 std::vector<const CBlockIndex*> vToFetch;
1488 int nMaxHeight = std::min<int>(state->pindexBestKnownBlock->nHeight, nWindowEnd + 1);
1489 bool is_limited_peer = IsLimitedPeer(peer);
1490 NodeId waitingfor = -1;
1491 while (pindexWalk->nHeight < nMaxHeight) {
1492 // Read up to 128 (or more, if more blocks than that are needed) successors of pindexWalk (towards
1493 // pindexBestKnownBlock) into vToFetch. We fetch 128, because CBlockIndex::GetAncestor may be as expensive
1494 // as iterating over ~100 CBlockIndex* entries anyway.
1495 int nToFetch = std::min(nMaxHeight - pindexWalk->nHeight, std::max<int>(count - vBlocks.size(), 128));
1496 vToFetch.resize(nToFetch);
1497 pindexWalk = state->pindexBestKnownBlock->GetAncestor(pindexWalk->nHeight + nToFetch);
1498 vToFetch[nToFetch - 1] = pindexWalk;
1499 for (unsigned int i = nToFetch - 1; i > 0; i--) {
1500 vToFetch[i - 1] = vToFetch[i]->pprev;
1501 }
1502 1503 // Iterate over those blocks in vToFetch (in forward direction), adding the ones that
1504 // are not yet downloaded and not in flight to vBlocks. In the meantime, update
1505 // pindexLastCommonBlock as long as all ancestors are already downloaded, or if it's
1506 // already part of our chain (and therefore don't need it even if pruned).
1507 for (const CBlockIndex* pindex : vToFetch) {
1508 if (!pindex->IsValid(BLOCK_VALID_TREE)) {
1509 // We consider the chain that this peer is on invalid.
1510 return;
1511 }
1512 1513 if (!CanServeWitnesses(peer) && DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) {
1514 // We wouldn't download this block or its descendants from this peer.
1515 return;
1516 }
1517 1518 if (pindex->nStatus & BLOCK_HAVE_DATA || (activeChain && activeChain->Contains(*pindex))) {
1519 if (activeChain && pindex->HaveNumChainTxs()) {
1520 state->pindexLastCommonBlock = pindex;
1521 }
1522 continue;
1523 }
1524 1525 // Is block in-flight?
1526 if (IsBlockRequested(pindex->GetBlockHash())) {
1527 if (waitingfor == -1) {
1528 // This is the first already-in-flight block.
1529 waitingfor = mapBlocksInFlight.lower_bound(pindex->GetBlockHash())->second.first;
1530 }
1531 continue;
1532 }
1533 1534 // The block is not already downloaded, and not yet in flight.
1535 if (pindex->nHeight > nWindowEnd) {
1536 // We reached the end of the window.
1537 if (vBlocks.size() == 0 && waitingfor != peer.m_id) {
1538 // We aren't able to fetch anything, but we would be if the download window was one larger.
1539 if (nodeStaller) *nodeStaller = waitingfor;
1540 }
1541 return;
1542 }
1543 1544 // Don't request blocks that go further than what limited peers can provide
1545 if (is_limited_peer && (state->pindexBestKnownBlock->nHeight - pindex->nHeight >= static_cast<int>(NODE_NETWORK_LIMITED_MIN_BLOCKS) - 2 /* two blocks buffer for possible races */)) {
1546 continue;
1547 }
1548 1549 vBlocks.push_back(pindex);
1550 if (vBlocks.size() == count) {
1551 return;
1552 }
1553 }
1554 }
1555 }
1556 1557 } // namespace
1558 1559 void PeerManagerImpl::PushNodeVersion(CNode& pnode, const Peer& peer)
1560 {
1561 uint64_t my_services;
1562 int64_t my_time;
1563 uint64_t your_services;
1564 CService your_addr;
1565 std::string my_user_agent;
1566 int my_height;
1567 bool my_tx_relay;
1568 if (pnode.IsPrivateBroadcastConn()) {
1569 my_services = NODE_NONE;
1570 my_time = 0;
1571 your_services = NODE_NONE;
1572 your_addr = CService{};
1573 my_user_agent = "/pynode:0.0.1/"; // Use a constant other than the default (or user-configured). See https://github.com/bitcoin/bitcoin/pull/27509#discussion_r1214671917
1574 my_height = 0;
1575 my_tx_relay = false;
1576 } else {
1577 const CAddress& addr{pnode.addr};
1578 my_services = peer.m_our_services;
1579 my_time = TicksSinceEpoch<std::chrono::seconds>(NodeClock::now());
1580 your_services = addr.nServices;
1581 your_addr = addr.IsRoutable() && !IsProxy(addr) && addr.IsAddrV1Compatible() ? CService{addr} : CService{};
1582 my_user_agent = strSubVersion;
1583 my_height = m_best_height;
1584 my_tx_relay = !RejectIncomingTxs(pnode);
1585 }
1586 1587 MakeAndPushMessage(
1588 pnode,
1589 NetMsgType::VERSION,
1590 pnode.AdvertisedVersion(),
1591 my_services,
1592 my_time,
1593 // your_services + CNetAddr::V1(your_addr) is the pre-version-31402 serialization of your_addr (without nTime)
1594 your_services, CNetAddr::V1(your_addr),
1595 // same, for a dummy address
1596 my_services, CNetAddr::V1(CService{}),
1597 pnode.GetLocalNonce(),
1598 my_user_agent,
1599 my_height,
1600 my_tx_relay);
1601 1602 LogDebug(
1603 BCLog::NET, "send version message: version=%d, blocks=%d%s, txrelay=%d, peer=%d\n",
1604 pnode.AdvertisedVersion(), my_height,
1605 fLogIPs ? strprintf(", them=%s", your_addr.ToStringAddrPort()) : "",
1606 my_tx_relay, pnode.GetId());
1607 }
1608 1609 void PeerManagerImpl::UpdateLastBlockAnnounceTime(NodeId node, int64_t time_in_seconds)
1610 {
1611 LOCK(cs_main);
1612 CNodeState *state = State(node);
1613 if (state) state->m_last_block_announcement = time_in_seconds;
1614 }
1615 1616 void PeerManagerImpl::InitializeNode(const CNode& node, ServiceFlags our_services)
1617 {
1618 NodeId nodeid = node.GetId();
1619 {
1620 LOCK(cs_main); // For m_node_states
1621 m_node_states.try_emplace(m_node_states.end(), nodeid);
1622 }
1623 WITH_LOCK(m_tx_download_mutex, m_txdownloadman.CheckIsEmpty(nodeid));
1624 1625 if (NetPermissions::HasFlag(node.m_permission_flags, NetPermissionFlags::BloomFilter)) {
1626 our_services = static_cast<ServiceFlags>(our_services | NODE_BLOOM);
1627 }
1628 1629 PeerRef peer = std::make_shared<Peer>(nodeid, our_services, node.IsInboundConn());
1630 {
1631 LOCK(m_peer_mutex);
1632 m_peer_map.emplace_hint(m_peer_map.end(), nodeid, peer);
1633 }
1634 }
1635 1636 void PeerManagerImpl::ReattemptInitialBroadcast(CScheduler& scheduler)
1637 {
1638 std::set<Txid> unbroadcast_txids = m_mempool.GetUnbroadcastTxs();
1639 1640 for (const auto& txid : unbroadcast_txids) {
1641 CTransactionRef tx = m_mempool.get(txid);
1642 1643 if (tx != nullptr) {
1644 InitiateTxBroadcastToAll(txid, tx->GetWitnessHash());
1645 } else {
1646 m_mempool.RemoveUnbroadcastTx(txid, true);
1647 }
1648 }
1649 1650 // Schedule next run for 10-15 minutes in the future.
1651 // We add randomness on every cycle to avoid the possibility of P2P fingerprinting.
1652 const auto delta = 10min + FastRandomContext().randrange<std::chrono::milliseconds>(5min);
1653 scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
1654 }
1655 1656 void PeerManagerImpl::ReattemptPrivateBroadcast(CScheduler& scheduler)
1657 {
1658 // Remove stale transactions that are no longer relevant (e.g. already in
1659 // the mempool or mined) and count the remaining ones.
1660 size_t num_for_rebroadcast{0};
1661 const auto stale_txs = m_tx_for_private_broadcast.GetStale();
1662 if (!stale_txs.empty()) {
1663 for (const auto& stale_tx : stale_txs) {
1664 // Only hold lock per single submission
1665 LOCK(cs_main);
1666 auto mempool_acceptable = m_chainman.ProcessTransaction(stale_tx, /*test_accept=*/true);
1667 if (mempool_acceptable.m_result_type == MempoolAcceptResult::ResultType::VALID) {
1668 LogDebug(BCLog::PRIVBROADCAST,
1669 "Reattempting broadcast of stale txid=%s wtxid=%s",
1670 stale_tx->GetHash().ToString(), stale_tx->GetWitnessHash().ToString());
1671 ++num_for_rebroadcast;
1672 } else {
1673 LogDebug(BCLog::PRIVBROADCAST, "Giving up broadcast attempts for txid=%s wtxid=%s: %s",
1674 stale_tx->GetHash().ToString(), stale_tx->GetWitnessHash().ToString(),
1675 mempool_acceptable.m_state.ToString());
1676 m_tx_for_private_broadcast.Remove(stale_tx);
1677 }
1678 }
1679 1680 // This could overshoot, but that is ok - we will open some private connections in vain.
1681 m_connman.m_private_broadcast.NumToOpenAdd(num_for_rebroadcast);
1682 }
1683 1684 const auto delta{2min + FastRandomContext().randrange<std::chrono::milliseconds>(1min)};
1685 scheduler.scheduleFromNow([&] { ReattemptPrivateBroadcast(scheduler); }, delta);
1686 }
1687 1688 void PeerManagerImpl::FinalizeNode(const CNode& node)
1689 {
1690 NodeId nodeid = node.GetId();
1691 {
1692 LOCK(cs_main);
1693 {
1694 // We remove the PeerRef from g_peer_map here, but we don't always
1695 // destruct the Peer. Sometimes another thread is still holding a
1696 // PeerRef, so the refcount is >= 1. Be careful not to do any
1697 // processing here that assumes Peer won't be changed before it's
1698 // destructed.
1699 PeerRef peer = RemovePeer(nodeid);
1700 assert(peer != nullptr);
1701 m_wtxid_relay_peers -= peer->m_wtxid_relay;
1702 assert(m_wtxid_relay_peers >= 0);
1703 }
1704 CNodeState *state = State(nodeid);
1705 assert(state != nullptr);
1706 1707 if (state->fSyncStarted)
1708 nSyncStarted--;
1709 1710 for (const QueuedBlock& entry : state->vBlocksInFlight) {
1711 auto range = mapBlocksInFlight.equal_range(entry.pindex->GetBlockHash());
1712 while (range.first != range.second) {
1713 auto [node_id, list_it] = range.first->second;
1714 if (node_id != nodeid) {
1715 range.first++;
1716 } else {
1717 range.first = mapBlocksInFlight.erase(range.first);
1718 }
1719 }
1720 }
1721 {
1722 LOCK(m_tx_download_mutex);
1723 m_txdownloadman.DisconnectedPeer(nodeid);
1724 }
1725 if (m_txreconciliation) m_txreconciliation->ForgetPeer(nodeid);
1726 m_num_preferred_download_peers -= state->fPreferredDownload;
1727 m_peers_downloading_from -= (!state->vBlocksInFlight.empty());
1728 assert(m_peers_downloading_from >= 0);
1729 m_outbound_peers_with_protect_from_disconnect -= state->m_chain_sync.m_protect;
1730 assert(m_outbound_peers_with_protect_from_disconnect >= 0);
1731 1732 m_node_states.erase(nodeid);
1733 1734 if (m_node_states.empty()) {
1735 // Do a consistency check after the last peer is removed.
1736 assert(mapBlocksInFlight.empty());
1737 assert(m_num_preferred_download_peers == 0);
1738 assert(m_peers_downloading_from == 0);
1739 assert(m_outbound_peers_with_protect_from_disconnect == 0);
1740 assert(m_wtxid_relay_peers == 0);
1741 WITH_LOCK(m_tx_download_mutex, m_txdownloadman.CheckIsEmpty());
1742 }
1743 } // cs_main
1744 if (node.fSuccessfullyConnected &&
1745 !node.IsBlockOnlyConn() && !node.IsPrivateBroadcastConn() && !node.IsInboundConn()) {
1746 // Only change visible addrman state for full outbound peers. We don't
1747 // call Connected() for feeler connections since they don't have
1748 // fSuccessfullyConnected set. Also don't call Connected() for private broadcast
1749 // connections since they could leak information in addrman.
1750 m_addrman.Connected(node.addr);
1751 }
1752 {
1753 LOCK(m_headers_presync_mutex);
1754 m_headers_presync_stats.erase(nodeid);
1755 }
1756 if (node.IsPrivateBroadcastConn() &&
1757 !m_tx_for_private_broadcast.DidNodeConfirmReception(nodeid) &&
1758 m_tx_for_private_broadcast.HavePendingTransactions()) {
1759 1760 m_connman.m_private_broadcast.NumToOpenAdd(1);
1761 }
1762 LogDebug(BCLog::NET, "Cleared nodestate for peer=%d\n", nodeid);
1763 }
1764 1765 bool PeerManagerImpl::HasAllDesirableServiceFlags(ServiceFlags services) const
1766 {
1767 // Shortcut for (services & GetDesirableServiceFlags(services)) == GetDesirableServiceFlags(services)
1768 return !(GetDesirableServiceFlags(services) & (~services));
1769 }
1770 1771 ServiceFlags PeerManagerImpl::GetDesirableServiceFlags(ServiceFlags services) const
1772 {
1773 if (services & NODE_NETWORK_LIMITED) {
1774 // Limited peers are desirable when we are close to the tip.
1775 if (ApproximateBestBlockDepth() < NODE_NETWORK_LIMITED_ALLOW_CONN_BLOCKS) {
1776 return ServiceFlags(NODE_NETWORK_LIMITED | NODE_WITNESS);
1777 }
1778 }
1779 return ServiceFlags(NODE_NETWORK | NODE_WITNESS);
1780 }
1781 1782 PeerRef PeerManagerImpl::GetPeerRef(NodeId id) const
1783 {
1784 LOCK(m_peer_mutex);
1785 auto it = m_peer_map.find(id);
1786 return it != m_peer_map.end() ? it->second : nullptr;
1787 }
1788 1789 PeerRef PeerManagerImpl::RemovePeer(NodeId id)
1790 {
1791 PeerRef ret;
1792 LOCK(m_peer_mutex);
1793 auto it = m_peer_map.find(id);
1794 if (it != m_peer_map.end()) {
1795 ret = std::move(it->second);
1796 m_peer_map.erase(it);
1797 }
1798 return ret;
1799 }
1800 1801 std::vector<PeerRef> PeerManagerImpl::GetAllPeers() const
1802 {
1803 std::vector<PeerRef> peers;
1804 LOCK(m_peer_mutex);
1805 peers.reserve(m_peer_map.size());
1806 for (const auto& [_, peer] : m_peer_map) {
1807 peers.push_back(peer);
1808 }
1809 return peers;
1810 }
1811 1812 bool PeerManagerImpl::GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) const
1813 {
1814 {
1815 LOCK(cs_main);
1816 const CNodeState* state = State(nodeid);
1817 if (state == nullptr)
1818 return false;
1819 stats.nSyncHeight = state->pindexBestKnownBlock ? state->pindexBestKnownBlock->nHeight : -1;
1820 stats.nCommonHeight = state->pindexLastCommonBlock ? state->pindexLastCommonBlock->nHeight : -1;
1821 for (const QueuedBlock& queue : state->vBlocksInFlight) {
1822 if (queue.pindex)
1823 stats.vHeightInFlight.push_back(queue.pindex->nHeight);
1824 }
1825 }
1826 1827 PeerRef peer = GetPeerRef(nodeid);
1828 if (peer == nullptr) return false;
1829 stats.their_services = peer->m_their_services;
1830 // It is common for nodes with good ping times to suddenly become lagged,
1831 // due to a new block arriving or other large transfer.
1832 // Merely reporting pingtime might fool the caller into thinking the node was still responsive,
1833 // since pingtime does not update until the ping is complete, which might take a while.
1834 // So, if a ping is taking an unusually long time in flight,
1835 // the caller can immediately detect that this is happening.
1836 NodeClock::duration ping_wait{0us};
1837 if ((0 != peer->m_ping_nonce_sent) && (peer->m_ping_start.load() > NodeClock::epoch)) {
1838 ping_wait = NodeClock::now() - peer->m_ping_start.load();
1839 }
1840 1841 if (auto tx_relay = peer->GetTxRelay(); tx_relay != nullptr) {
1842 stats.m_relay_txs = WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs);
1843 stats.m_fee_filter_received = tx_relay->m_fee_filter_received.load();
1844 LOCK(tx_relay->m_tx_inventory_mutex);
1845 stats.m_last_inv_seq = tx_relay->m_last_inv_sequence;
1846 stats.m_inv_to_send = tx_relay->m_tx_inventory_to_send.size();
1847 } else {
1848 stats.m_relay_txs = false;
1849 stats.m_fee_filter_received = 0;
1850 stats.m_inv_to_send = 0;
1851 }
1852 1853 stats.m_ping_wait = ping_wait;
1854 stats.m_addr_processed = peer->m_addr_processed.load();
1855 stats.m_addr_rate_limited = peer->m_addr_rate_limited.load();
1856 stats.m_addr_relay_enabled = peer->m_addr_relay_enabled.load();
1857 {
1858 LOCK(peer->m_headers_sync_mutex);
1859 if (peer->m_headers_sync) {
1860 stats.presync_height = peer->m_headers_sync->GetPresyncHeight();
1861 }
1862 }
1863 stats.time_offset = peer->m_time_offset;
1864 1865 return true;
1866 }
1867 1868 std::vector<node::TxOrphanage::OrphanInfo> PeerManagerImpl::GetOrphanTransactions()
1869 {
1870 LOCK(m_tx_download_mutex);
1871 return m_txdownloadman.GetOrphanTransactions();
1872 }
1873 1874 PeerManagerInfo PeerManagerImpl::GetInfo() const
1875 {
1876 return PeerManagerInfo{
1877 .median_outbound_time_offset = m_outbound_time_offsets.Median(),
1878 .ignores_incoming_txs = m_opts.ignore_incoming_txs,
1879 .private_broadcast = m_opts.private_broadcast,
1880 };
1881 }
1882 1883 std::vector<PrivateBroadcast::TxBroadcastInfo> PeerManagerImpl::GetPrivateBroadcastInfo() const
1884 {
1885 return m_tx_for_private_broadcast.GetBroadcastInfo();
1886 }
1887 1888 std::vector<CTransactionRef> PeerManagerImpl::AbortPrivateBroadcast(const uint256& id)
1889 {
1890 const auto snapshot{m_tx_for_private_broadcast.GetBroadcastInfo()};
1891 std::vector<CTransactionRef> removed_txs;
1892 1893 size_t connections_cancelled{0};
1894 for (const auto& tx_info : snapshot) {
1895 const CTransactionRef& tx{tx_info.tx};
1896 if (tx->GetHash().ToUint256() != id && tx->GetWitnessHash().ToUint256() != id) continue;
1897 if (const auto peer_acks{m_tx_for_private_broadcast.Remove(tx)}) {
1898 removed_txs.push_back(tx);
1899 if (NUM_PRIVATE_BROADCAST_PER_TX > *peer_acks) {
1900 connections_cancelled += (NUM_PRIVATE_BROADCAST_PER_TX - *peer_acks);
1901 }
1902 }
1903 }
1904 m_connman.m_private_broadcast.NumToOpenSub(connections_cancelled);
1905 1906 return removed_txs;
1907 }
1908 1909 void PeerManagerImpl::AddToCompactExtraTransactions(const CTransactionRef& tx)
1910 {
1911 if (m_opts.max_extra_txs == 0) return;
1912 if (vExtraTxnForCompact.size() < m_opts.max_extra_txs) {
1913 if (vExtraTxnForCompact.empty()) vExtraTxnForCompact.reserve(m_opts.max_extra_txs);
1914 vExtraTxnForCompact.emplace_back(tx->GetWitnessHash(), tx);
1915 } else {
1916 vExtraTxnForCompact[vExtraTxnForCompactIt] = std::make_pair(tx->GetWitnessHash(), tx);
1917 }
1918 vExtraTxnForCompactIt = (vExtraTxnForCompactIt + 1) % m_opts.max_extra_txs;
1919 }
1920 1921 void PeerManagerImpl::Misbehaving(Peer& peer, const std::string& message)
1922 {
1923 LOCK(peer.m_misbehavior_mutex);
1924 1925 const std::string message_prefixed = message.empty() ? "" : (": " + message);
1926 peer.m_should_discourage = true;
1927 LogDebug(BCLog::NET, "Misbehaving: peer=%d%s\n", peer.m_id, message_prefixed);
1928 TRACEPOINT(net, misbehaving_connection,
1929 peer.m_id,
1930 message.c_str()
1931 );
1932 }
1933 1934 void PeerManagerImpl::MaybePunishNodeForBlock(NodeId nodeid, const BlockValidationState& state,
1935 bool via_compact_block, const std::string& message)
1936 {
1937 PeerRef peer{GetPeerRef(nodeid)};
1938 switch (state.GetResult()) {
1939 case BlockValidationResult::BLOCK_RESULT_UNSET:
1940 break;
1941 case BlockValidationResult::BLOCK_HEADER_LOW_WORK:
1942 // We didn't try to process the block because the header chain may have
1943 // too little work.
1944 break;
1945 // The node is providing invalid data:
1946 case BlockValidationResult::BLOCK_CONSENSUS:
1947 case BlockValidationResult::BLOCK_MUTATED:
1948 if (!via_compact_block) {
1949 if (peer) Misbehaving(*peer, message);
1950 return;
1951 }
1952 break;
1953 case BlockValidationResult::BLOCK_CACHED_INVALID:
1954 {
1955 // Discourage outbound (but not inbound) peers if on an invalid chain.
1956 // Exempt HB compact block peers. Manual connections are always protected from discouragement.
1957 if (peer && !via_compact_block && !peer->m_is_inbound) {
1958 if (peer) Misbehaving(*peer, message);
1959 return;
1960 }
1961 break;
1962 }
1963 case BlockValidationResult::BLOCK_INVALID_HEADER:
1964 case BlockValidationResult::BLOCK_INVALID_PREV:
1965 if (peer) Misbehaving(*peer, message);
1966 return;
1967 // Conflicting (but not necessarily invalid) data or different policy:
1968 case BlockValidationResult::BLOCK_MISSING_PREV:
1969 if (peer) Misbehaving(*peer, message);
1970 return;
1971 case BlockValidationResult::BLOCK_TIME_FUTURE:
1972 break;
1973 }
1974 if (message != "") {
1975 LogDebug(BCLog::NET, "peer=%d: %s\n", nodeid, message);
1976 }
1977 }
1978 1979 bool PeerManagerImpl::BlockRequestAllowed(const CBlockIndex& block_index)
1980 {
1981 AssertLockHeld(cs_main);
1982 if (m_chainman.ActiveChain().Contains(block_index)) return true;
1983 return block_index.IsValid(BLOCK_VALID_SCRIPTS) && (m_chainman.m_best_header != nullptr) &&
1984 (m_chainman.m_best_header->GetBlockTime() - block_index.GetBlockTime() < STALE_RELAY_AGE_LIMIT) &&
1985 (GetBlockProofEquivalentTime(*m_chainman.m_best_header, block_index, *m_chainman.m_best_header, m_chainparams.GetConsensus()) < STALE_RELAY_AGE_LIMIT);
1986 }
1987 1988 util::Expected<void, std::string> PeerManagerImpl::FetchBlock(NodeId peer_id, const CBlockIndex& block_index)
1989 {
1990 if (m_chainman.m_blockman.LoadingBlocks()) return util::Unexpected{"Loading blocks ..."};
1991 1992 // The lock must be taken here before fetching Peer so another thread does
1993 // not delete the CNodeState from under the current thread, causing an
1994 // assertion failure in BlockRequested. This lock can be replaced with a
1995 // net-specific lock when more of CNodeState is moved into Peer.
1996 LOCK(cs_main);
1997 1998 // Ensure this peer exists and hasn't been disconnected
1999 PeerRef peer = GetPeerRef(peer_id);
2000 if (peer == nullptr) return util::Unexpected{"Peer does not exist"};
2001 2002 // Ignore pre-segwit peers
2003 if (!CanServeWitnesses(*peer)) return util::Unexpected{"Pre-SegWit peer"};
2004 2005 // Forget about all prior requests
2006 RemoveBlockRequest(block_index.GetBlockHash(), std::nullopt);
2007 2008 // Mark block as in-flight
2009 if (!BlockRequested(peer_id, block_index)) return util::Unexpected{"Already requested from this peer"};
2010 2011 // Construct message to request the block
2012 const uint256& hash{block_index.GetBlockHash()};
2013 std::vector<CInv> invs{CInv(MSG_BLOCK | MSG_WITNESS_FLAG, hash)};
2014 2015 // Send block request message to the peer
2016 bool success = m_connman.ForNode(peer_id, [this, &invs](CNode* node) {
2017 this->MakeAndPushMessage(*node, NetMsgType::GETDATA, invs);
2018 return true;
2019 });
2020 2021 if (!success) return util::Unexpected{"Peer not fully connected"};
2022 2023 LogDebug(BCLog::NET, "Requesting block %s from peer=%d\n",
2024 hash.ToString(), peer_id);
2025 return {};
2026 }
2027 2028 std::unique_ptr<PeerManager> PeerManager::make(CConnman& connman, AddrMan& addrman,
2029 BanMan* banman, ChainstateManager& chainman,
2030 CTxMemPool& pool, node::Warnings& warnings, Options opts)
2031 {
2032 return std::make_unique<PeerManagerImpl>(connman, addrman, banman, chainman, pool, warnings, opts);
2033 }
2034 2035 PeerManagerImpl::PeerManagerImpl(CConnman& connman, AddrMan& addrman,
2036 BanMan* banman, ChainstateManager& chainman,
2037 CTxMemPool& pool, node::Warnings& warnings, Options opts)
2038 : m_rng{opts.deterministic_rng},
2039 m_fee_filter_rounder{CFeeRate{DEFAULT_MIN_RELAY_TX_FEE}, m_rng},
2040 m_chainparams(chainman.GetParams()),
2041 m_connman(connman),
2042 m_addrman(addrman),
2043 m_banman(banman),
2044 m_chainman(chainman),
2045 m_mempool(pool),
2046 m_txdownloadman(node::TxDownloadOptions{pool, m_rng, opts.deterministic_rng}),
2047 m_warnings{warnings},
2048 m_opts{opts}
2049 {
2050 // While Erlay support is incomplete, it must be enabled explicitly via -txreconciliation.
2051 // This argument can go away after Erlay support is complete.
2052 if (opts.reconcile_txs) {
2053 m_txreconciliation = std::make_unique<TxReconciliationTracker>(TXRECONCILIATION_VERSION);
2054 }
2055 }
2056 2057 void PeerManagerImpl::StartScheduledTasks(CScheduler& scheduler)
2058 {
2059 // Stale tip checking and peer eviction are on two different timers, but we
2060 // don't want them to get out of sync due to drift in the scheduler, so we
2061 // combine them in one function and schedule at the quicker (peer-eviction)
2062 // timer.
2063 static_assert(EXTRA_PEER_CHECK_INTERVAL < STALE_CHECK_INTERVAL, "peer eviction timer should be less than stale tip check timer");
2064 scheduler.scheduleEvery([this] { this->CheckForStaleTipAndEvictPeers(); }, std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL});
2065 2066 // schedule next run for 10-15 minutes in the future
2067 const auto delta = 10min + FastRandomContext().randrange<std::chrono::milliseconds>(5min);
2068 scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
2069 2070 if (m_opts.private_broadcast) {
2071 scheduler.scheduleFromNow([&] { ReattemptPrivateBroadcast(scheduler); }, 0min);
2072 }
2073 }
2074 2075 void PeerManagerImpl::ActiveTipChange(const CBlockIndex& new_tip, bool is_ibd)
2076 {
2077 // Ensure mempool mutex was released, otherwise deadlock may occur if another thread holding
2078 // m_tx_download_mutex waits on the mempool mutex.
2079 AssertLockNotHeld(m_mempool.cs);
2080 AssertLockNotHeld(m_tx_download_mutex);
2081 2082 if (!is_ibd) {
2083 LOCK(m_tx_download_mutex);
2084 // If the chain tip has changed, previously rejected transactions might now be valid, e.g. due
2085 // to a timelock. Reset the rejection filters to give those transactions another chance if we
2086 // see them again.
2087 m_txdownloadman.ActiveTipChange();
2088 }
2089 }
2090 2091 /**
2092 * Evict orphan txn pool entries based on a newly connected
2093 * block, remember the recently confirmed transactions, and delete tracked
2094 * announcements for them. Also save the time of the last tip update and
2095 * possibly reduce dynamic block stalling timeout.
2096 */
2097 void PeerManagerImpl::BlockConnected(
2098 const ChainstateRole& role,
2099 const std::shared_ptr<const CBlock>& pblock,
2100 const CBlockIndex* pindex)
2101 {
2102 // Update this for all chainstate roles so that we don't mistakenly see peers
2103 // helping us do background IBD as having a stale tip.
2104 m_last_tip_update = GetTime<std::chrono::seconds>();
2105 2106 // In case the dynamic timeout was doubled once or more, reduce it slowly back to its default value
2107 auto stalling_timeout = m_block_stalling_timeout.load();
2108 Assume(stalling_timeout >= BLOCK_STALLING_TIMEOUT_DEFAULT);
2109 if (stalling_timeout != BLOCK_STALLING_TIMEOUT_DEFAULT) {
2110 const auto new_timeout = std::max(std::chrono::duration_cast<std::chrono::seconds>(stalling_timeout * 0.85), BLOCK_STALLING_TIMEOUT_DEFAULT);
2111 if (m_block_stalling_timeout.compare_exchange_strong(stalling_timeout, new_timeout)) {
2112 LogDebug(BCLog::NET, "Decreased stalling timeout to %d seconds\n", count_seconds(new_timeout));
2113 }
2114 }
2115 2116 // The following task can be skipped since we don't maintain a mempool for
2117 // the historical chainstate, or during ibd since we don't receive incoming
2118 // transactions from peers into the mempool.
2119 if (!role.historical && !m_chainman.IsInitialBlockDownload()) {
2120 LOCK(m_tx_download_mutex);
2121 m_txdownloadman.BlockConnected(pblock);
2122 }
2123 }
2124 2125 void PeerManagerImpl::BlockDisconnected(const std::shared_ptr<const CBlock> &block, const CBlockIndex* pindex)
2126 {
2127 LOCK(m_tx_download_mutex);
2128 m_txdownloadman.BlockDisconnected();
2129 }
2130 2131 /**
2132 * Maintain state about the best-seen block and fast-announce a compact block
2133 * to compatible peers.
2134 */
2135 void PeerManagerImpl::NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& pblock)
2136 {
2137 auto pcmpctblock = std::make_shared<const CBlockHeaderAndShortTxIDs>(*pblock, FastRandomContext().rand64());
2138 2139 LOCK(cs_main);
2140 2141 if (pindex->nHeight <= m_highest_fast_announce)
2142 return;
2143 m_highest_fast_announce = pindex->nHeight;
2144 2145 if (!DeploymentActiveAt(*pindex, m_chainman, Consensus::DEPLOYMENT_SEGWIT)) return;
2146 2147 uint256 hashBlock(pblock->GetHash());
2148 const std::shared_future<CSerializedNetMsg> lazy_ser{
2149 std::async(std::launch::deferred, [&] { return NetMsg::Make(NetMsgType::CMPCTBLOCK, *pcmpctblock); })};
2150 2151 {
2152 auto most_recent_block_txs = std::make_unique<std::map<GenTxid, CTransactionRef>>();
2153 for (const auto& tx : pblock->vtx) {
2154 most_recent_block_txs->emplace(tx->GetHash(), tx);
2155 most_recent_block_txs->emplace(tx->GetWitnessHash(), tx);
2156 }
2157 2158 LOCK(m_most_recent_block_mutex);
2159 m_most_recent_block_hash = hashBlock;
2160 m_most_recent_block = pblock;
2161 m_most_recent_compact_block = pcmpctblock;
2162 m_most_recent_block_txs = std::move(most_recent_block_txs);
2163 }
2164 2165 m_connman.ForEachNode([this, pindex, &lazy_ser, &hashBlock](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
2166 AssertLockHeld(::cs_main);
2167 2168 if (pnode->GetCommonVersion() < INVALID_CB_NO_BAN_VERSION || pnode->fDisconnect)
2169 return;
2170 ProcessBlockAvailability(pnode->GetId());
2171 CNodeState &state = *State(pnode->GetId());
2172 // If the peer has, or we announced to them the previous block already,
2173 // but we don't think they have this one, go ahead and announce it
2174 if (state.m_requested_hb_cmpctblocks && !PeerHasHeader(&state, pindex) && PeerHasHeader(&state, pindex->pprev)) {
2175 2176 LogDebug(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n", "PeerManager::NewPoWValidBlock",
2177 hashBlock.ToString(), pnode->GetId());
2178 2179 const CSerializedNetMsg& ser_cmpctblock{lazy_ser.get()};
2180 PushMessage(*pnode, ser_cmpctblock.Copy());
2181 state.pindexBestHeaderSent = pindex;
2182 }
2183 });
2184 }
2185 2186 /**
2187 * Update our best height and announce any block hashes which weren't previously
2188 * in m_chainman.ActiveChain() to our peers.
2189 */
2190 void PeerManagerImpl::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload)
2191 {
2192 SetBestBlock(pindexNew->nHeight, std::chrono::seconds{pindexNew->GetBlockTime()});
2193 2194 // Don't relay inventory during initial block download.
2195 if (fInitialDownload) return;
2196 2197 // Find the hashes of all blocks that weren't previously in the best chain.
2198 std::vector<uint256> vHashes;
2199 const CBlockIndex *pindexToAnnounce = pindexNew;
2200 while (pindexToAnnounce != pindexFork) {
2201 vHashes.push_back(pindexToAnnounce->GetBlockHash());
2202 pindexToAnnounce = pindexToAnnounce->pprev;
2203 if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
2204 // Limit announcements in case of a huge reorganization.
2205 // Rely on the peer's synchronization mechanism in that case.
2206 break;
2207 }
2208 }
2209 2210 {
2211 LOCK(m_peer_mutex);
2212 for (auto& it : m_peer_map) {
2213 Peer& peer = *it.second;
2214 LOCK(peer.m_block_inv_mutex);
2215 for (const uint256& hash : vHashes | std::views::reverse) {
2216 peer.m_blocks_for_headers_relay.push_back(hash);
2217 }
2218 }
2219 }
2220 2221 m_connman.WakeMessageHandler();
2222 }
2223 2224 /**
2225 * Handle invalid block rejection and consequent peer discouragement, maintain which
2226 * peers announce compact blocks.
2227 */
2228 void PeerManagerImpl::BlockChecked(const std::shared_ptr<const CBlock>& block, const BlockValidationState& state)
2229 {
2230 LOCK(cs_main);
2231 2232 const uint256 hash(block->GetHash());
2233 std::map<uint256, std::pair<NodeId, bool>>::iterator it = mapBlockSource.find(hash);
2234 2235 // If the block failed validation, we know where it came from and we're still connected
2236 // to that peer, maybe punish.
2237 if (state.IsInvalid() &&
2238 it != mapBlockSource.end() &&
2239 State(it->second.first)) {
2240 MaybePunishNodeForBlock(/*nodeid=*/ it->second.first, state, /*via_compact_block=*/ !it->second.second);
2241 }
2242 // Check that:
2243 // 1. The block is valid
2244 // 2. We're not in initial block download
2245 // 3. This is currently the best block we're aware of. We haven't updated
2246 // the tip yet so we have no way to check this directly here. Instead we
2247 // just check that there are currently no other blocks in flight.
2248 else if (state.IsValid() &&
2249 !m_chainman.IsInitialBlockDownload() &&
2250 mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
2251 if (it != mapBlockSource.end()) {
2252 MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first);
2253 }
2254 }
2255 if (it != mapBlockSource.end())
2256 mapBlockSource.erase(it);
2257 }
2258 2259 //////////////////////////////////////////////////////////////////////////////
2260 //
2261 // Messages
2262 //
2263 2264 bool PeerManagerImpl::AlreadyHaveBlock(const uint256& block_hash)
2265 {
2266 return m_chainman.m_blockman.LookupBlockIndex(block_hash) != nullptr;
2267 }
2268 2269 void PeerManagerImpl::SendPings()
2270 {
2271 LOCK(m_peer_mutex);
2272 for(auto& it : m_peer_map) it.second->m_ping_queued = true;
2273 }
2274 2275 void PeerManagerImpl::InitiateTxBroadcastToAll(const Txid& txid, const Wtxid& wtxid)
2276 {
2277 for (const PeerRef& peer_ref : GetAllPeers()) {
2278 if (!peer_ref) continue;
2279 Peer& peer{*peer_ref};
2280 2281 auto tx_relay = peer.GetTxRelay();
2282 if (!tx_relay) continue;
2283 2284 LOCK(tx_relay->m_tx_inventory_mutex);
2285 // Only queue transactions for announcement once the version handshake
2286 // is completed. The time of arrival for these transactions is
2287 // otherwise at risk of leaking to a spy, if the spy is able to
2288 // distinguish transactions received during the handshake from the rest
2289 // in the announcement.
2290 if (tx_relay->m_next_inv_send_time == 0s) continue;
2291 2292 const uint256& hash{peer.m_wtxid_relay ? wtxid.ToUint256() : txid.ToUint256()};
2293 if (!tx_relay->m_tx_inventory_known_filter.contains(hash)) {
2294 tx_relay->m_tx_inventory_to_send.insert(wtxid);
2295 }
2296 }
2297 }
2298 2299 node::TransactionError PeerManagerImpl::InitiateTxBroadcastPrivate(const CTransactionRef& tx)
2300 {
2301 const auto txstr{strprintf("txid=%s, wtxid=%s", tx->GetHash().ToString(), tx->GetWitnessHash().ToString())};
2302 switch (m_tx_for_private_broadcast.Add(tx)) {
2303 case PrivateBroadcast::AddResult::Added:
2304 LogDebug(BCLog::PRIVBROADCAST, "Requesting %d new connections due to %s", NUM_PRIVATE_BROADCAST_PER_TX, txstr);
2305 m_connman.m_private_broadcast.NumToOpenAdd(NUM_PRIVATE_BROADCAST_PER_TX);
2306 return node::TransactionError::OK;
2307 case PrivateBroadcast::AddResult::AlreadyPresent:
2308 LogDebug(BCLog::PRIVBROADCAST, "Ignoring unnecessary request to schedule an already scheduled transaction: %s", txstr);
2309 return node::TransactionError::OK;
2310 case PrivateBroadcast::AddResult::QueueFull:
2311 LogDebug(BCLog::PRIVBROADCAST, "Rejecting private broadcast, queue full (cap=%u): %s", PrivateBroadcast::MAX_TRANSACTIONS, txstr);
2312 return node::TransactionError::PRIVATE_BROADCAST_FULL;
2313 } // no default case, so the compiler can warn about missing cases
2314 assert(false);
2315 }
2316 2317 void PeerManagerImpl::RelayAddress(NodeId originator,
2318 const CAddress& addr,
2319 bool fReachable)
2320 {
2321 // We choose the same nodes within a given 24h window (if the list of connected
2322 // nodes does not change) and we don't relay to nodes that already know an
2323 // address. So within 24h we will likely relay a given address once. This is to
2324 // prevent a peer from unjustly giving their address better propagation by sending
2325 // it to us repeatedly.
2326 2327 if (!fReachable && !addr.IsRelayable()) return;
2328 2329 // Relay to a limited number of other nodes
2330 // Use deterministic randomness to send to the same nodes for 24 hours
2331 // at a time so the m_addr_knowns of the chosen nodes prevent repeats
2332 const uint64_t hash_addr{CServiceHash(0, 0)(addr)};
2333 const auto current_time{GetTime<std::chrono::seconds>()};
2334 // Adding address hash makes exact rotation time different per address, while preserving periodicity.
2335 const uint64_t time_addr{(static_cast<uint64_t>(count_seconds(current_time)) + hash_addr) / count_seconds(ROTATE_ADDR_RELAY_DEST_INTERVAL)};
2336 const CSipHasher hasher{m_connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY)
2337 .Write(hash_addr)
2338 .Write(time_addr)};
2339 2340 // Relay reachable addresses to 2 peers. Unreachable addresses are relayed randomly to 1 or 2 peers.
2341 unsigned int nRelayNodes = (fReachable || (hasher.Finalize() & 1)) ? 2 : 1;
2342 2343 std::array<std::pair<uint64_t, Peer*>, 2> best{{{0, nullptr}, {0, nullptr}}};
2344 assert(nRelayNodes <= best.size());
2345 2346 LOCK(m_peer_mutex);
2347 2348 for (auto& [id, peer] : m_peer_map) {
2349 if (peer->m_addr_relay_enabled && id != originator && IsAddrCompatible(*peer, addr)) {
2350 uint64_t hashKey = CSipHasher(hasher).Write(id).Finalize();
2351 for (unsigned int i = 0; i < nRelayNodes; i++) {
2352 if (hashKey > best[i].first) {
2353 std::copy(best.begin() + i, best.begin() + nRelayNodes - 1, best.begin() + i + 1);
2354 best[i] = std::make_pair(hashKey, peer.get());
2355 break;
2356 }
2357 }
2358 }
2359 };
2360 2361 for (unsigned int i = 0; i < nRelayNodes && best[i].first != 0; i++) {
2362 PushAddress(*best[i].second, addr);
2363 }
2364 }
2365 2366 void PeerManagerImpl::ProcessGetBlockData(CNode& pfrom, Peer& peer, const CInv& inv)
2367 {
2368 std::shared_ptr<const CBlock> a_recent_block;
2369 std::shared_ptr<const CBlockHeaderAndShortTxIDs> a_recent_compact_block;
2370 {
2371 LOCK(m_most_recent_block_mutex);
2372 a_recent_block = m_most_recent_block;
2373 a_recent_compact_block = m_most_recent_compact_block;
2374 }
2375 2376 bool need_activate_chain = false;
2377 {
2378 LOCK(cs_main);
2379 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
2380 if (pindex) {
2381 if (pindex->HaveNumChainTxs() && !pindex->IsValid(BLOCK_VALID_SCRIPTS) &&
2382 pindex->IsValid(BLOCK_VALID_TREE)) {
2383 // If we have the block and all of its parents, but have not yet validated it,
2384 // we might be in the middle of connecting it (ie in the unlock of cs_main
2385 // before ActivateBestChain but after AcceptBlock).
2386 // In this case, we need to run ActivateBestChain prior to checking the relay
2387 // conditions below.
2388 need_activate_chain = true;
2389 }
2390 }
2391 } // release cs_main before calling ActivateBestChain
2392 if (need_activate_chain) {
2393 BlockValidationState state;
2394 if (!m_chainman.ActiveChainstate().ActivateBestChain(state, a_recent_block)) {
2395 LogDebug(BCLog::NET, "failed to activate chain (%s)\n", state.ToString());
2396 }
2397 }
2398 2399 const CBlockIndex* pindex{nullptr};
2400 const CBlockIndex* tip{nullptr};
2401 bool can_direct_fetch{false};
2402 FlatFilePos block_pos{};
2403 {
2404 LOCK(cs_main);
2405 pindex = m_chainman.m_blockman.LookupBlockIndex(inv.hash);
2406 if (!pindex) {
2407 return;
2408 }
2409 if (!BlockRequestAllowed(*pindex)) {
2410 LogDebug(BCLog::NET, "%s: ignoring request from peer=%i for old block that isn't in the main chain\n", __func__, pfrom.GetId());
2411 return;
2412 }
2413 // disconnect node in case we have reached the outbound limit for serving historical blocks
2414 if (m_connman.OutboundTargetReached(true) &&
2415 (((m_chainman.m_best_header != nullptr) && (m_chainman.m_best_header->GetBlockTime() - pindex->GetBlockTime() > HISTORICAL_BLOCK_AGE)) || inv.IsMsgFilteredBlk()) &&
2416 !pfrom.HasPermission(NetPermissionFlags::Download) // nodes with the download permission may exceed target
2417 ) {
2418 LogDebug(BCLog::NET, "historical block serving limit reached, %s", pfrom.DisconnectMsg());
2419 pfrom.fDisconnect = true;
2420 return;
2421 }
2422 tip = m_chainman.ActiveChain().Tip();
2423 // Avoid leaking prune-height by never sending blocks below the NODE_NETWORK_LIMITED threshold
2424 if (!pfrom.HasPermission(NetPermissionFlags::NoBan) && (
2425 (((peer.m_our_services & NODE_NETWORK_LIMITED) == NODE_NETWORK_LIMITED) && ((peer.m_our_services & NODE_NETWORK) != NODE_NETWORK) && (tip->nHeight - pindex->nHeight > (int)NODE_NETWORK_LIMITED_MIN_BLOCKS + 2 /* add two blocks buffer extension for possible races */) )
2426 )) {
2427 LogDebug(BCLog::NET, "Ignore block request below NODE_NETWORK_LIMITED threshold, %s", pfrom.DisconnectMsg());
2428 //disconnect node and prevent it from stalling (would otherwise wait for the missing block)
2429 pfrom.fDisconnect = true;
2430 return;
2431 }
2432 // Pruned nodes may have deleted the block, so check whether
2433 // it's available before trying to send.
2434 if (!(pindex->nStatus & BLOCK_HAVE_DATA)) {
2435 return;
2436 }
2437 can_direct_fetch = CanDirectFetch();
2438 block_pos = pindex->GetBlockPos();
2439 }
2440 2441 std::shared_ptr<const CBlock> pblock;
2442 if (a_recent_block && a_recent_block->GetHash() == inv.hash) {
2443 pblock = a_recent_block;
2444 } else if (inv.IsMsgWitnessBlk()) {
2445 // Fast-path: in this case it is possible to serve the block directly from disk,
2446 // as the network format matches the format on disk
2447 if (const auto block_data{m_chainman.m_blockman.ReadRawBlock(block_pos)}) {
2448 MakeAndPushMessage(pfrom, NetMsgType::BLOCK, std::span{*block_data});
2449 } else {
2450 if (WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.IsBlockPruned(*pindex))) {
2451 LogDebug(BCLog::NET, "Block was pruned before it could be read, %s", pfrom.DisconnectMsg());
2452 } else {
2453 LogError("Cannot load block from disk, %s", pfrom.DisconnectMsg());
2454 }
2455 pfrom.fDisconnect = true;
2456 return;
2457 }
2458 // Don't set pblock as we've sent the block
2459 } else {
2460 // Send block from disk
2461 std::shared_ptr<CBlock> pblockRead = std::make_shared<CBlock>();
2462 if (!m_chainman.m_blockman.ReadBlock(*pblockRead, block_pos, inv.hash)) {
2463 if (WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.IsBlockPruned(*pindex))) {
2464 LogDebug(BCLog::NET, "Block was pruned before it could be read, %s", pfrom.DisconnectMsg());
2465 } else {
2466 LogError("Cannot load block from disk, %s", pfrom.DisconnectMsg());
2467 }
2468 pfrom.fDisconnect = true;
2469 return;
2470 }
2471 pblock = pblockRead;
2472 }
2473 if (pblock) {
2474 if (inv.IsMsgBlk()) {
2475 MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_NO_WITNESS(*pblock));
2476 } else if (inv.IsMsgWitnessBlk()) {
2477 MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_WITH_WITNESS(*pblock));
2478 } else if (inv.IsMsgFilteredBlk()) {
2479 bool sendMerkleBlock = false;
2480 CMerkleBlock merkleBlock;
2481 if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
2482 LOCK(tx_relay->m_bloom_filter_mutex);
2483 if (tx_relay->m_bloom_filter) {
2484 sendMerkleBlock = true;
2485 merkleBlock = CMerkleBlock(*pblock, *tx_relay->m_bloom_filter);
2486 }
2487 }
2488 if (sendMerkleBlock) {
2489 MakeAndPushMessage(pfrom, NetMsgType::MERKLEBLOCK, merkleBlock);
2490 // CMerkleBlock just contains hashes, so also push any transactions in the block the client did not see
2491 // This avoids hurting performance by pointlessly requiring a round-trip
2492 // Note that there is currently no way for a node to request any single transactions we didn't send here -
2493 // they must either disconnect and retry or request the full block.
2494 // Thus, the protocol spec specified allows for us to provide duplicate txn here,
2495 // however we MUST always provide at least what the remote peer needs
2496 for (const auto& [tx_idx, _] : merkleBlock.vMatchedTxn)
2497 MakeAndPushMessage(pfrom, NetMsgType::TX, TX_NO_WITNESS(*pblock->vtx[tx_idx]));
2498 }
2499 // else
2500 // no response
2501 } else if (inv.IsMsgCmpctBlk()) {
2502 // If a peer is asking for old blocks, we're almost guaranteed
2503 // they won't have a useful mempool to match against a compact block,
2504 // and we don't feel like constructing the object for them, so
2505 // instead we respond with the full, non-compact block.
2506 if (can_direct_fetch && pindex->nHeight >= tip->nHeight - MAX_CMPCTBLOCK_DEPTH) {
2507 if (a_recent_compact_block && a_recent_compact_block->header.GetHash() == inv.hash) {
2508 MakeAndPushMessage(pfrom, NetMsgType::CMPCTBLOCK, *a_recent_compact_block);
2509 } else {
2510 CBlockHeaderAndShortTxIDs cmpctblock{*pblock, m_rng.rand64()};
2511 MakeAndPushMessage(pfrom, NetMsgType::CMPCTBLOCK, cmpctblock);
2512 }
2513 } else {
2514 MakeAndPushMessage(pfrom, NetMsgType::BLOCK, TX_WITH_WITNESS(*pblock));
2515 }
2516 }
2517 }
2518 2519 {
2520 LOCK(peer.m_block_inv_mutex);
2521 // Trigger the peer node to send a getblocks request for the next batch of inventory
2522 if (inv.hash == peer.m_continuation_block) {
2523 // Send immediately. This must send even if redundant,
2524 // and we want it right after the last block so they don't
2525 // wait for other stuff first.
2526 std::vector<CInv> vInv;
2527 vInv.emplace_back(MSG_BLOCK, tip->GetBlockHash());
2528 MakeAndPushMessage(pfrom, NetMsgType::INV, vInv);
2529 peer.m_continuation_block.SetNull();
2530 }
2531 }
2532 }
2533 2534 CTransactionRef PeerManagerImpl::FindTxForGetData(const Peer::TxRelay& tx_relay, const GenTxid& gtxid)
2535 {
2536 // If a tx was in the mempool prior to the last INV for this peer, permit the request.
2537 auto txinfo{std::visit(
2538 [&](const auto& id) {
2539 return m_mempool.info_for_relay(id, WITH_LOCK(tx_relay.m_tx_inventory_mutex, return tx_relay.m_last_inv_sequence));
2540 },
2541 gtxid)};
2542 if (txinfo.tx) {
2543 return std::move(txinfo.tx);
2544 }
2545 2546 // Or it might be from the most recent block
2547 {
2548 LOCK(m_most_recent_block_mutex);
2549 if (m_most_recent_block_txs != nullptr) {
2550 auto it = m_most_recent_block_txs->find(gtxid);
2551 if (it != m_most_recent_block_txs->end()) return it->second;
2552 }
2553 }
2554 2555 return {};
2556 }
2557 2558 void PeerManagerImpl::ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic<bool>& interruptMsgProc)
2559 {
2560 AssertLockNotHeld(cs_main);
2561 2562 auto tx_relay = peer.GetTxRelay();
2563 2564 std::deque<CInv>::iterator it = peer.m_getdata_requests.begin();
2565 std::vector<CInv> vNotFound;
2566 2567 // Process as many TX items from the front of the getdata queue as
2568 // possible, since they're common and it's efficient to batch process
2569 // them.
2570 while (it != peer.m_getdata_requests.end() && it->IsGenTxMsg()) {
2571 if (interruptMsgProc) return;
2572 // The send buffer provides backpressure. If there's no space in
2573 // the buffer, pause processing until the next call.
2574 if (pfrom.fPauseSend) break;
2575 2576 const CInv &inv = *it++;
2577 2578 if (tx_relay == nullptr) {
2579 // Ignore GETDATA requests for transactions from block-relay-only
2580 // peers and peers that asked us not to announce transactions.
2581 continue;
2582 }
2583 2584 if (auto tx{FindTxForGetData(*tx_relay, ToGenTxid(inv))}) {
2585 // WTX and WITNESS_TX imply we serialize with witness
2586 const auto maybe_with_witness = (inv.IsMsgTx() ? TX_NO_WITNESS : TX_WITH_WITNESS);
2587 MakeAndPushMessage(pfrom, NetMsgType::TX, maybe_with_witness(*tx));
2588 m_mempool.RemoveUnbroadcastTx(tx->GetHash());
2589 } else {
2590 vNotFound.push_back(inv);
2591 }
2592 }
2593 2594 // Only process one BLOCK item per call, since they're uncommon and can be
2595 // expensive to process.
2596 if (it != peer.m_getdata_requests.end() && !pfrom.fPauseSend) {
2597 const CInv &inv = *it++;
2598 if (inv.IsGenBlkMsg()) {
2599 ProcessGetBlockData(pfrom, peer, inv);
2600 }
2601 // else: If the first item on the queue is an unknown type, we erase it
2602 // and continue processing the queue on the next call.
2603 // NOTE: previously we wouldn't do so and the peer sending us a malformed GETDATA could
2604 // result in never making progress and this thread using 100% allocated CPU. See
2605 // https://bitcoincore.org/en/2024/07/03/disclose-getdata-cpu.
2606 }
2607 2608 peer.m_getdata_requests.erase(peer.m_getdata_requests.begin(), it);
2609 2610 if (!vNotFound.empty()) {
2611 // Let the peer know that we didn't find what it asked for, so it doesn't
2612 // have to wait around forever.
2613 // SPV clients care about this message: it's needed when they are
2614 // recursively walking the dependencies of relevant unconfirmed
2615 // transactions. SPV clients want to do that because they want to know
2616 // about (and store and rebroadcast and risk analyze) the dependencies
2617 // of transactions relevant to them, without having to download the
2618 // entire memory pool.
2619 // Also, other nodes can use these messages to automatically request a
2620 // transaction from some other peer that announced it, and stop
2621 // waiting for us to respond.
2622 // In normal operation, we often send NOTFOUND messages for parents of
2623 // transactions that we relay; if a peer is missing a parent, they may
2624 // assume we have them and request the parents from us.
2625 MakeAndPushMessage(pfrom, NetMsgType::NOTFOUND, vNotFound);
2626 }
2627 }
2628 2629 uint32_t PeerManagerImpl::GetFetchFlags(const Peer& peer) const
2630 {
2631 uint32_t nFetchFlags = 0;
2632 if (CanServeWitnesses(peer)) {
2633 nFetchFlags |= MSG_WITNESS_FLAG;
2634 }
2635 return nFetchFlags;
2636 }
2637 2638 void PeerManagerImpl::SendBlockTransactions(CNode& pfrom, Peer& peer, const CBlock& block, const BlockTransactionsRequest& req)
2639 {
2640 BlockTransactions resp(req);
2641 for (size_t i = 0; i < req.indexes.size(); i++) {
2642 if (req.indexes[i] >= block.vtx.size()) {
2643 Misbehaving(peer, "getblocktxn with out-of-bounds tx indices");
2644 return;
2645 }
2646 resp.txn[i] = block.vtx[req.indexes[i]];
2647 }
2648 2649 if (util::log::ShouldDebugLog(BCLog::CMPCTBLOCK)) {
2650 uint32_t tx_requested_size{0};
2651 for (const auto& tx : resp.txn) tx_requested_size += tx->ComputeTotalSize();
2652 LogDebug(BCLog::CMPCTBLOCK, "%s sent us a GETBLOCKTXN for block %s, sending a BLOCKTXN with %u txns. (%u bytes)", pfrom.LogPeer(), block.GetHash().ToString(), resp.txn.size(), tx_requested_size);
2653 }
2654 MakeAndPushMessage(pfrom, NetMsgType::BLOCKTXN, resp);
2655 }
2656 2657 bool PeerManagerImpl::CheckHeadersPoW(const std::vector<CBlockHeader>& headers, Peer& peer)
2658 {
2659 // Do these headers have proof-of-work matching what's claimed?
2660 if (!HasValidProofOfWork(headers, m_chainparams.GetConsensus())) {
2661 Misbehaving(peer, "header with invalid proof of work");
2662 return false;
2663 }
2664 2665 // Are these headers connected to each other?
2666 if (!CheckHeadersAreContinuous(headers)) {
2667 Misbehaving(peer, "non-continuous headers sequence");
2668 return false;
2669 }
2670 return true;
2671 }
2672 2673 arith_uint256 PeerManagerImpl::GetAntiDoSWorkThreshold()
2674 {
2675 arith_uint256 near_chaintip_work = 0;
2676 LOCK(cs_main);
2677 if (m_chainman.ActiveChain().Tip() != nullptr) {
2678 const CBlockIndex *tip = m_chainman.ActiveChain().Tip();
2679 // Use a 144 block buffer, so that we'll accept headers that fork from
2680 // near our tip.
2681 near_chaintip_work = tip->nChainWork - std::min<arith_uint256>(144*GetBlockProof(*tip), tip->nChainWork);
2682 }
2683 return std::max(near_chaintip_work, m_chainman.MinimumChainWork());
2684 }
2685 2686 /**
2687 * Special handling for unconnecting headers that might be part of a block
2688 * announcement.
2689 *
2690 * We'll send a getheaders message in response to try to connect the chain.
2691 */
2692 void PeerManagerImpl::HandleUnconnectingHeaders(CNode& pfrom, Peer& peer,
2693 const std::vector<CBlockHeader>& headers)
2694 {
2695 // Try to fill in the missing headers.
2696 const CBlockIndex* best_header{WITH_LOCK(cs_main, return m_chainman.m_best_header)};
2697 if (MaybeSendGetHeaders(pfrom, GetLocator(best_header), peer)) {
2698 LogDebug(BCLog::NET, "received header %s: missing prev block %s, sending getheaders (%d) to end (peer=%d)\n",
2699 headers[0].GetHash().ToString(),
2700 headers[0].hashPrevBlock.ToString(),
2701 best_header->nHeight,
2702 pfrom.GetId());
2703 }
2704 2705 // Set hashLastUnknownBlock for this peer, so that if we
2706 // eventually get the headers - even from a different peer -
2707 // we can use this peer to download.
2708 WITH_LOCK(cs_main, UpdateBlockAvailability(pfrom.GetId(), headers.back().GetHash()));
2709 }
2710 2711 bool PeerManagerImpl::CheckHeadersAreContinuous(const std::vector<CBlockHeader>& headers) const
2712 {
2713 uint256 hashLastBlock;
2714 for (const CBlockHeader& header : headers) {
2715 if (!hashLastBlock.IsNull() && header.hashPrevBlock != hashLastBlock) {
2716 return false;
2717 }
2718 hashLastBlock = header.GetHash();
2719 }
2720 return true;
2721 }
2722 2723 bool PeerManagerImpl::IsContinuationOfLowWorkHeadersSync(Peer& peer, CNode& pfrom, std::vector<CBlockHeader>& headers)
2724 {
2725 if (peer.m_headers_sync) {
2726 auto result = peer.m_headers_sync->ProcessNextHeaders(headers, headers.size() == m_opts.max_headers_result);
2727 // If it is a valid continuation, we should treat the existing getheaders request as responded to.
2728 if (result.success) peer.m_last_getheaders_timestamp = {};
2729 if (result.request_more) {
2730 auto locator = peer.m_headers_sync->NextHeadersRequestLocator();
2731 // If we were instructed to ask for a locator, it should not be empty.
2732 Assume(!locator.vHave.empty());
2733 // We can only be instructed to request more if processing was successful.
2734 Assume(result.success);
2735 if (!locator.vHave.empty()) {
2736 // It should be impossible for the getheaders request to fail,
2737 // because we just cleared the last getheaders timestamp.
2738 bool sent_getheaders = MaybeSendGetHeaders(pfrom, locator, peer);
2739 Assume(sent_getheaders);
2740 LogDebug(BCLog::NET, "more getheaders (from %s) to peer=%d\n",
2741 locator.vHave.front().ToString(), pfrom.GetId());
2742 }
2743 }
2744 2745 if (peer.m_headers_sync->GetState() == HeadersSyncState::State::FINAL) {
2746 peer.m_headers_sync.reset(nullptr);
2747 2748 // Delete this peer's entry in m_headers_presync_stats.
2749 // If this is m_headers_presync_bestpeer, it will be replaced later
2750 // by the next peer that triggers the else{} branch below.
2751 LOCK(m_headers_presync_mutex);
2752 m_headers_presync_stats.erase(pfrom.GetId());
2753 } else {
2754 // Build statistics for this peer's sync.
2755 HeadersPresyncStats stats;
2756 stats.first = peer.m_headers_sync->GetPresyncWork();
2757 if (peer.m_headers_sync->GetState() == HeadersSyncState::State::PRESYNC) {
2758 stats.second = {peer.m_headers_sync->GetPresyncHeight(),
2759 peer.m_headers_sync->GetPresyncTime()};
2760 }
2761 2762 // Update statistics in stats.
2763 LOCK(m_headers_presync_mutex);
2764 m_headers_presync_stats[pfrom.GetId()] = stats;
2765 auto best_it = m_headers_presync_stats.find(m_headers_presync_bestpeer);
2766 bool best_updated = false;
2767 if (best_it == m_headers_presync_stats.end()) {
2768 // If the cached best peer is outdated, iterate over all remaining ones (including
2769 // newly updated one) to find the best one.
2770 NodeId peer_best{-1};
2771 const HeadersPresyncStats* stat_best{nullptr};
2772 for (const auto& [peer, stat] : m_headers_presync_stats) {
2773 if (!stat_best || stat > *stat_best) {
2774 peer_best = peer;
2775 stat_best = &stat;
2776 }
2777 }
2778 m_headers_presync_bestpeer = peer_best;
2779 best_updated = (peer_best == pfrom.GetId());
2780 } else if (best_it->first == pfrom.GetId() || stats > best_it->second) {
2781 // pfrom was and remains the best peer, or pfrom just became best.
2782 m_headers_presync_bestpeer = pfrom.GetId();
2783 best_updated = true;
2784 }
2785 if (best_updated && stats.second.has_value()) {
2786 // If the best peer updated, and it is in its first phase, signal.
2787 m_headers_presync_should_signal = true;
2788 }
2789 }
2790 2791 if (result.success) {
2792 // We only overwrite the headers passed in if processing was
2793 // successful.
2794 headers.swap(result.pow_validated_headers);
2795 }
2796 2797 return result.success;
2798 }
2799 // Either we didn't have a sync in progress, or something went wrong
2800 // processing these headers, or we are returning headers to the caller to
2801 // process.
2802 return false;
2803 }
2804 2805 bool PeerManagerImpl::TryLowWorkHeadersSync(Peer& peer, CNode& pfrom, const CBlockIndex& chain_start_header, std::vector<CBlockHeader>& headers)
2806 {
2807 // Calculate the claimed total work on this chain.
2808 arith_uint256 total_work = chain_start_header.nChainWork + CalculateClaimedHeadersWork(headers);
2809 2810 // Our dynamic anti-DoS threshold (minimum work required on a headers chain
2811 // before we'll store it)
2812 arith_uint256 minimum_chain_work = GetAntiDoSWorkThreshold();
2813 2814 // Avoid DoS via low-difficulty-headers by only processing if the headers
2815 // are part of a chain with sufficient work.
2816 if (total_work < minimum_chain_work) {
2817 // Only try to sync with this peer if their headers message was full;
2818 // otherwise they don't have more headers after this so no point in
2819 // trying to sync their too-little-work chain.
2820 if (headers.size() == m_opts.max_headers_result) {
2821 // Note: we could advance to the last header in this set that is
2822 // known to us, rather than starting at the first header (which we
2823 // may already have); however this is unlikely to matter much since
2824 // ProcessHeadersMessage() already handles the case where all
2825 // headers in a received message are already known and are
2826 // ancestors of m_best_header or chainActive.Tip(), by skipping
2827 // this logic in that case. So even if the first header in this set
2828 // of headers is known, some header in this set must be new, so
2829 // advancing to the first unknown header would be a small effect.
2830 LOCK(peer.m_headers_sync_mutex);
2831 peer.m_headers_sync.reset(new HeadersSyncState(peer.m_id, m_chainparams.GetConsensus(),
2832 m_chainparams.HeadersSync(), chain_start_header, minimum_chain_work));
2833 2834 // Now a HeadersSyncState object for tracking this synchronization
2835 // is created, process the headers using it as normal. Failures are
2836 // handled inside of IsContinuationOfLowWorkHeadersSync.
2837 (void)IsContinuationOfLowWorkHeadersSync(peer, pfrom, headers);
2838 } else {
2839 LogDebug(BCLog::NET, "Ignoring low-work chain (height=%u) from peer=%d\n", chain_start_header.nHeight + headers.size(), pfrom.GetId());
2840 }
2841 2842 // The peer has not yet given us a chain that meets our work threshold,
2843 // so we want to prevent further processing of the headers in any case.
2844 headers = {};
2845 return true;
2846 }
2847 2848 return false;
2849 }
2850 2851 bool PeerManagerImpl::IsAncestorOfBestHeaderOrTip(const CBlockIndex* header)
2852 {
2853 if (header == nullptr) {
2854 return false;
2855 } else if (m_chainman.m_best_header != nullptr && header == m_chainman.m_best_header->GetAncestor(header->nHeight)) {
2856 return true;
2857 } else if (m_chainman.ActiveChain().Contains(*header)) {
2858 return true;
2859 }
2860 return false;
2861 }
2862 2863 bool PeerManagerImpl::MaybeSendGetHeaders(CNode& pfrom, const CBlockLocator& locator, Peer& peer)
2864 {
2865 const auto current_time = NodeClock::now();
2866 2867 // Only allow a new getheaders message to go out if we don't have a recent
2868 // one already in-flight
2869 if (current_time - peer.m_last_getheaders_timestamp > HEADERS_RESPONSE_TIME) {
2870 MakeAndPushMessage(pfrom, NetMsgType::GETHEADERS, locator, uint256());
2871 peer.m_last_getheaders_timestamp = current_time;
2872 return true;
2873 }
2874 return false;
2875 }
2876 2877 /*
2878 * Given a new headers tip ending in last_header, potentially request blocks towards that tip.
2879 * We require that the given tip have at least as much work as our tip, and for
2880 * our current tip to be "close to synced" (see CanDirectFetch()).
2881 */
2882 void PeerManagerImpl::HeadersDirectFetchBlocks(CNode& pfrom, const Peer& peer, const CBlockIndex& last_header)
2883 {
2884 LOCK(cs_main);
2885 CNodeState *nodestate = State(pfrom.GetId());
2886 2887 if (CanDirectFetch() && last_header.IsValid(BLOCK_VALID_TREE) && m_chainman.ActiveChain().Tip()->nChainWork <= last_header.nChainWork) {
2888 std::vector<const CBlockIndex*> vToFetch;
2889 const CBlockIndex* pindexWalk{&last_header};
2890 // Calculate all the blocks we'd need to switch to last_header, up to a limit.
2891 while (pindexWalk && !m_chainman.ActiveChain().Contains(*pindexWalk) && vToFetch.size() <= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
2892 if (!(pindexWalk->nStatus & BLOCK_HAVE_DATA) &&
2893 !IsBlockRequested(pindexWalk->GetBlockHash()) &&
2894 (!DeploymentActiveAt(*pindexWalk, m_chainman, Consensus::DEPLOYMENT_SEGWIT) || CanServeWitnesses(peer))) {
2895 // We don't have this block, and it's not yet in flight.
2896 vToFetch.push_back(pindexWalk);
2897 }
2898 pindexWalk = pindexWalk->pprev;
2899 }
2900 // If pindexWalk still isn't on our main chain, we're looking at a
2901 // very large reorg at a time we think we're close to caught up to
2902 // the main chain -- this shouldn't really happen. Bail out on the
2903 // direct fetch and rely on parallel download instead.
2904 // Common ancestor must exist (genesis).
2905 if (!m_chainman.ActiveChain().Contains(*Assert(pindexWalk))) {
2906 LogDebug(BCLog::NET, "Large reorg, won't direct fetch to %s (%d)\n",
2907 last_header.GetBlockHash().ToString(),
2908 last_header.nHeight);
2909 } else {
2910 std::vector<CInv> vGetData;
2911 // Download as much as possible, from earliest to latest.
2912 for (const CBlockIndex* pindex : vToFetch | std::views::reverse) {
2913 if (nodestate->vBlocksInFlight.size() >= MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
2914 // Can't download any more from this peer
2915 break;
2916 }
2917 uint32_t nFetchFlags = GetFetchFlags(peer);
2918 vGetData.emplace_back(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash());
2919 BlockRequested(pfrom.GetId(), *pindex);
2920 LogDebug(BCLog::NET, "Requesting block %s from peer=%d",
2921 pindex->GetBlockHash().ToString(), pfrom.GetId());
2922 }
2923 if (vGetData.size() > 1) {
2924 LogDebug(BCLog::NET, "Downloading blocks toward %s (%d) via headers direct fetch\n",
2925 last_header.GetBlockHash().ToString(),
2926 last_header.nHeight);
2927 }
2928 if (vGetData.size() > 0) {
2929 if (!m_opts.ignore_incoming_txs &&
2930 nodestate->m_provides_cmpctblocks &&
2931 vGetData.size() == 1 &&
2932 mapBlocksInFlight.size() == 1 &&
2933 last_header.pprev->IsValid(BLOCK_VALID_CHAIN)) {
2934 // In any case, we want to download using a compact block, not a regular one
2935 vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
2936 }
2937 MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vGetData);
2938 }
2939 }
2940 }
2941 }
2942 2943 /**
2944 * Given receipt of headers from a peer ending in last_header, along with
2945 * whether that header was new and whether the headers message was full,
2946 * update the state we keep for the peer.
2947 */
2948 void PeerManagerImpl::UpdatePeerStateForReceivedHeaders(CNode& pfrom, Peer& peer,
2949 const CBlockIndex& last_header, bool received_new_header, bool may_have_more_headers)
2950 {
2951 LOCK(cs_main);
2952 CNodeState *nodestate = State(pfrom.GetId());
2953 2954 UpdateBlockAvailability(pfrom.GetId(), last_header.GetBlockHash());
2955 2956 // From here, pindexBestKnownBlock should be guaranteed to be non-null,
2957 // because it is set in UpdateBlockAvailability. Some nullptr checks
2958 // are still present, however, as belt-and-suspenders.
2959 2960 if (received_new_header && last_header.nChainWork > m_chainman.ActiveChain().Tip()->nChainWork) {
2961 nodestate->m_last_block_announcement = GetTime();
2962 }
2963 2964 // If we're in IBD, we want outbound peers that will serve us a useful
2965 // chain. Disconnect peers that are on chains with insufficient work.
2966 if (m_chainman.IsInitialBlockDownload() && !may_have_more_headers) {
2967 // If the peer has no more headers to give us, then we know we have
2968 // their tip.
2969 if (nodestate->pindexBestKnownBlock && nodestate->pindexBestKnownBlock->nChainWork < m_chainman.MinimumChainWork()) {
2970 // This peer has too little work on their headers chain to help
2971 // us sync -- disconnect if it is an outbound disconnection
2972 // candidate.
2973 // Note: We compare their tip to the minimum chain work (rather than
2974 // m_chainman.ActiveChain().Tip()) because we won't start block download
2975 // until we have a headers chain that has at least
2976 // the minimum chain work, even if a peer has a chain past our tip,
2977 // as an anti-DoS measure.
2978 if (pfrom.IsOutboundOrBlockRelayConn()) {
2979 LogInfo("outbound peer headers chain has insufficient work, %s", pfrom.DisconnectMsg());
2980 pfrom.fDisconnect = true;
2981 }
2982 }
2983 }
2984 2985 // If this is an outbound full-relay peer, check to see if we should protect
2986 // it from the bad/lagging chain logic.
2987 // Note that outbound block-relay peers are excluded from this protection, and
2988 // thus always subject to eviction under the bad/lagging chain logic.
2989 // See ChainSyncTimeoutState.
2990 if (!pfrom.fDisconnect && pfrom.IsFullOutboundConn() && nodestate->pindexBestKnownBlock != nullptr) {
2991 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) {
2992 LogDebug(BCLog::NET, "Protecting outbound peer=%d from eviction\n", pfrom.GetId());
2993 nodestate->m_chain_sync.m_protect = true;
2994 ++m_outbound_peers_with_protect_from_disconnect;
2995 }
2996 }
2997 }
2998 2999 void PeerManagerImpl::ProcessHeadersMessage(CNode& pfrom, Peer& peer,
3000 std::vector<CBlockHeader>&& headers,
3001 bool via_compact_block)
3002 {
3003 size_t nCount = headers.size();
3004 3005 if (nCount == 0) {
3006 // Nothing interesting. Stop asking this peers for more headers.
3007 // If we were in the middle of headers sync, receiving an empty headers
3008 // message suggests that the peer suddenly has nothing to give us
3009 // (perhaps it reorged to our chain). Clear download state for this peer.
3010 LOCK(peer.m_headers_sync_mutex);
3011 if (peer.m_headers_sync) {
3012 peer.m_headers_sync.reset(nullptr);
3013 LOCK(m_headers_presync_mutex);
3014 m_headers_presync_stats.erase(pfrom.GetId());
3015 }
3016 // A headers message with no headers cannot be an announcement, so assume
3017 // it is a response to our last getheaders request, if there is one.
3018 peer.m_last_getheaders_timestamp = {};
3019 return;
3020 }
3021 3022 // Before we do any processing, make sure these pass basic sanity checks.
3023 // We'll rely on headers having valid proof-of-work further down, as an
3024 // anti-DoS criteria (note: this check is required before passing any
3025 // headers into HeadersSyncState).
3026 if (!CheckHeadersPoW(headers, peer)) {
3027 // Misbehaving() calls are handled within CheckHeadersPoW(), so we can
3028 // just return. (Note that even if a header is announced via compact
3029 // block, the header itself should be valid, so this type of error can
3030 // always be punished.)
3031 return;
3032 }
3033 3034 const CBlockIndex *pindexLast = nullptr;
3035 3036 // We'll set already_validated_work to true if these headers are
3037 // successfully processed as part of a low-work headers sync in progress
3038 // (either in PRESYNC or REDOWNLOAD phase).
3039 // If true, this will mean that any headers returned to us (ie during
3040 // REDOWNLOAD) can be validated without further anti-DoS checks.
3041 bool already_validated_work = false;
3042 3043 // If we're in the middle of headers sync, let it do its magic.
3044 bool have_headers_sync = false;
3045 {
3046 LOCK(peer.m_headers_sync_mutex);
3047 3048 already_validated_work = IsContinuationOfLowWorkHeadersSync(peer, pfrom, headers);
3049 3050 // The headers we passed in may have been:
3051 // - untouched, perhaps if no headers-sync was in progress, or some
3052 // failure occurred
3053 // - erased, such as if the headers were successfully processed and no
3054 // additional headers processing needs to take place (such as if we
3055 // are still in PRESYNC)
3056 // - replaced with headers that are now ready for validation, such as
3057 // during the REDOWNLOAD phase of a low-work headers sync.
3058 // So just check whether we still have headers that we need to process,
3059 // or not.
3060 if (headers.empty()) {
3061 return;
3062 }
3063 3064 have_headers_sync = !!peer.m_headers_sync;
3065 }
3066 3067 // Do these headers connect to something in our block index?
3068 const CBlockIndex *chain_start_header{WITH_LOCK(::cs_main, return m_chainman.m_blockman.LookupBlockIndex(headers[0].hashPrevBlock))};
3069 bool headers_connect_blockindex{chain_start_header != nullptr};
3070 3071 if (!headers_connect_blockindex) {
3072 // This could be a BIP 130 block announcement, use
3073 // special logic for handling headers that don't connect, as this
3074 // could be benign.
3075 HandleUnconnectingHeaders(pfrom, peer, headers);
3076 return;
3077 }
3078 3079 // If headers connect, assume that this is in response to any outstanding getheaders
3080 // request we may have sent, and clear out the time of our last request. Non-connecting
3081 // headers cannot be a response to a getheaders request.
3082 peer.m_last_getheaders_timestamp = {};
3083 3084 // If the headers we received are already in memory and an ancestor of
3085 // m_best_header or our tip, skip anti-DoS checks. These headers will not
3086 // use any more memory (and we are not leaking information that could be
3087 // used to fingerprint us).
3088 const CBlockIndex *last_received_header{nullptr};
3089 {
3090 LOCK(cs_main);
3091 last_received_header = m_chainman.m_blockman.LookupBlockIndex(headers.back().GetHash());
3092 already_validated_work = already_validated_work || IsAncestorOfBestHeaderOrTip(last_received_header);
3093 }
3094 3095 // If our peer has NetPermissionFlags::NoBan privileges, then bypass our
3096 // anti-DoS logic (this saves bandwidth when we connect to a trusted peer
3097 // on startup).
3098 if (pfrom.HasPermission(NetPermissionFlags::NoBan)) {
3099 already_validated_work = true;
3100 }
3101 3102 // At this point, the headers connect to something in our block index.
3103 // Do anti-DoS checks to determine if we should process or store for later
3104 // processing.
3105 if (!already_validated_work && TryLowWorkHeadersSync(peer, pfrom,
3106 *chain_start_header, headers)) {
3107 // If we successfully started a low-work headers sync, then there
3108 // should be no headers to process any further.
3109 Assume(headers.empty());
3110 return;
3111 }
3112 3113 // At this point, we have a set of headers with sufficient work on them
3114 // which can be processed.
3115 3116 // If we don't have the last header, then this peer will have given us
3117 // something new (if these headers are valid).
3118 bool received_new_header{last_received_header == nullptr};
3119 3120 // Now process all the headers.
3121 BlockValidationState state;
3122 const bool processed{m_chainman.ProcessNewBlockHeaders(headers,
3123 /*min_pow_checked=*/true,
3124 state, &pindexLast)};
3125 if (!processed) {
3126 if (state.IsInvalid()) {
3127 if (!pfrom.IsInboundConn() && state.GetResult() == BlockValidationResult::BLOCK_CACHED_INVALID) {
3128 // Warn user if outgoing peers send us headers of blocks that we previously marked as invalid.
3129 LogWarning("%s (received from peer=%i). "
3130 "If this happens with all peers, consider database corruption (that -reindex may fix) "
3131 "or a potential consensus incompatibility.",
3132 state.GetDebugMessage(), pfrom.GetId());
3133 }
3134 MaybePunishNodeForBlock(pfrom.GetId(), state, via_compact_block, "invalid header received");
3135 return;
3136 }
3137 }
3138 assert(pindexLast);
3139 3140 if (processed && received_new_header) {
3141 LogBlockHeader(*pindexLast, pfrom, /*via_compact_block=*/false);
3142 }
3143 3144 // Consider fetching more headers if we are not using our headers-sync mechanism.
3145 if (nCount == m_opts.max_headers_result && !have_headers_sync) {
3146 // Headers message had its maximum size; the peer may have more headers.
3147 if (MaybeSendGetHeaders(pfrom, GetLocator(pindexLast), peer)) {
3148 LogDebug(BCLog::NET, "more getheaders (%d) to end to peer=%d", pindexLast->nHeight, pfrom.GetId());
3149 }
3150 }
3151 3152 UpdatePeerStateForReceivedHeaders(pfrom, peer, *pindexLast, received_new_header, nCount == m_opts.max_headers_result);
3153 3154 // Consider immediately downloading blocks.
3155 HeadersDirectFetchBlocks(pfrom, peer, *pindexLast);
3156 3157 return;
3158 }
3159 3160 std::optional<node::PackageToValidate> PeerManagerImpl::ProcessInvalidTx(NodeId nodeid, const CTransactionRef& ptx, const TxValidationState& state,
3161 bool first_time_failure)
3162 {
3163 AssertLockNotHeld(m_peer_mutex);
3164 AssertLockHeld(g_msgproc_mutex);
3165 AssertLockHeld(m_tx_download_mutex);
3166 3167 PeerRef peer{GetPeerRef(nodeid)};
3168 3169 LogDebug(BCLog::MEMPOOLREJ, "%s (wtxid=%s) from peer=%d was not accepted: %s\n",
3170 ptx->GetHash().ToString(),
3171 ptx->GetWitnessHash().ToString(),
3172 nodeid,
3173 state.ToString());
3174 3175 const auto& [add_extra_compact_tx, unique_parents, package_to_validate] = m_txdownloadman.MempoolRejectedTx(ptx, state, nodeid, first_time_failure);
3176 3177 if (add_extra_compact_tx && RecursiveDynamicUsage(*ptx) < 100000) {
3178 AddToCompactExtraTransactions(ptx);
3179 }
3180 for (const Txid& parent_txid : unique_parents) {
3181 if (peer) AddKnownTx(*peer, parent_txid.ToUint256());
3182 }
3183 3184 return package_to_validate;
3185 }
3186 3187 void PeerManagerImpl::ProcessValidTx(NodeId nodeid, const CTransactionRef& tx, const std::list<CTransactionRef>& replaced_transactions)
3188 {
3189 AssertLockNotHeld(m_peer_mutex);
3190 AssertLockHeld(g_msgproc_mutex);
3191 AssertLockHeld(m_tx_download_mutex);
3192 3193 m_txdownloadman.MempoolAcceptedTx(tx);
3194 3195 LogDebug(BCLog::MEMPOOL, "AcceptToMemoryPool: peer=%d: accepted %s (wtxid=%s) (poolsz %u txn, %u kB)\n",
3196 nodeid,
3197 tx->GetHash().ToString(),
3198 tx->GetWitnessHash().ToString(),
3199 m_mempool.size(), m_mempool.DynamicMemoryUsage() / 1000);
3200 3201 InitiateTxBroadcastToAll(tx->GetHash(), tx->GetWitnessHash());
3202 3203 for (const CTransactionRef& removedTx : replaced_transactions) {
3204 AddToCompactExtraTransactions(removedTx);
3205 }
3206 }
3207 3208 void PeerManagerImpl::ProcessPackageResult(const node::PackageToValidate& package_to_validate, const PackageMempoolAcceptResult& package_result)
3209 {
3210 AssertLockNotHeld(m_peer_mutex);
3211 AssertLockHeld(g_msgproc_mutex);
3212 AssertLockHeld(m_tx_download_mutex);
3213 3214 const auto& package = package_to_validate.m_txns;
3215 const auto& senders = package_to_validate.m_senders;
3216 3217 if (package_result.m_state.IsInvalid()) {
3218 m_txdownloadman.MempoolRejectedPackage(package);
3219 }
3220 // We currently only expect to process 1-parent-1-child packages. Remove if this changes.
3221 if (!Assume(package.size() == 2)) return;
3222 3223 // Iterate backwards to erase in-package descendants from the orphanage before they become
3224 // relevant in AddChildrenToWorkSet.
3225 auto package_iter = package.rbegin();
3226 auto senders_iter = senders.rbegin();
3227 while (package_iter != package.rend()) {
3228 const auto& tx = *package_iter;
3229 const NodeId nodeid = *senders_iter;
3230 const auto it_result{package_result.m_tx_results.find(tx->GetWitnessHash())};
3231 3232 // It is not guaranteed that a result exists for every transaction.
3233 if (it_result != package_result.m_tx_results.end()) {
3234 const auto& tx_result = it_result->second;
3235 switch (tx_result.m_result_type) {
3236 case MempoolAcceptResult::ResultType::VALID:
3237 {
3238 ProcessValidTx(nodeid, tx, tx_result.m_replaced_transactions);
3239 break;
3240 }
3241 case MempoolAcceptResult::ResultType::INVALID:
3242 case MempoolAcceptResult::ResultType::DIFFERENT_WITNESS:
3243 {
3244 // Don't add to vExtraTxnForCompact, as these transactions should have already been
3245 // added there when added to the orphanage or rejected for TX_RECONSIDERABLE.
3246 // This should be updated if package submission is ever used for transactions
3247 // that haven't already been validated before.
3248 ProcessInvalidTx(nodeid, tx, tx_result.m_state, /*first_time_failure=*/false);
3249 break;
3250 }
3251 case MempoolAcceptResult::ResultType::MEMPOOL_ENTRY:
3252 {
3253 // AlreadyHaveTx() should be catching transactions that are already in mempool.
3254 Assume(false);
3255 break;
3256 }
3257 }
3258 }
3259 package_iter++;
3260 senders_iter++;
3261 }
3262 }
3263 3264 // NOTE: the orphan processing used to be uninterruptible and quadratic, which could allow a peer to stall the node for
3265 // hours with specially crafted transactions. See https://bitcoincore.org/en/2024/07/03/disclose-orphan-dos.
3266 bool PeerManagerImpl::ProcessOrphanTx(Peer& peer)
3267 {
3268 AssertLockHeld(g_msgproc_mutex);
3269 LOCK2(::cs_main, m_tx_download_mutex);
3270 3271 CTransactionRef porphanTx = nullptr;
3272 3273 while (CTransactionRef porphanTx = m_txdownloadman.GetTxToReconsider(peer.m_id)) {
3274 const MempoolAcceptResult result = m_chainman.ProcessTransaction(porphanTx);
3275 const TxValidationState& state = result.m_state;
3276 const Txid& orphanHash = porphanTx->GetHash();
3277 const Wtxid& orphan_wtxid = porphanTx->GetWitnessHash();
3278 3279 if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
3280 LogDebug(BCLog::TXPACKAGES, " accepted orphan tx %s (wtxid=%s)\n", orphanHash.ToString(), orphan_wtxid.ToString());
3281 ProcessValidTx(peer.m_id, porphanTx, result.m_replaced_transactions);
3282 return true;
3283 } else if (state.GetResult() != TxValidationResult::TX_MISSING_INPUTS) {
3284 LogDebug(BCLog::TXPACKAGES, " invalid orphan tx %s (wtxid=%s) from peer=%d. %s\n",
3285 orphanHash.ToString(),
3286 orphan_wtxid.ToString(),
3287 peer.m_id,
3288 state.ToString());
3289 3290 if (Assume(state.IsInvalid() &&
3291 state.GetResult() != TxValidationResult::TX_UNKNOWN &&
3292 state.GetResult() != TxValidationResult::TX_NO_MEMPOOL &&
3293 state.GetResult() != TxValidationResult::TX_RESULT_UNSET)) {
3294 ProcessInvalidTx(peer.m_id, porphanTx, state, /*first_time_failure=*/false);
3295 }
3296 return true;
3297 }
3298 }
3299 3300 return false;
3301 }
3302 3303 bool PeerManagerImpl::PrepareBlockFilterRequest(CNode& node, Peer& peer,
3304 BlockFilterType filter_type, uint32_t start_height,
3305 const uint256& stop_hash, uint32_t max_height_diff,
3306 const CBlockIndex*& stop_index,
3307 BlockFilterIndex*& filter_index)
3308 {
3309 const bool supported_filter_type =
3310 (filter_type == BlockFilterType::BASIC &&
3311 (peer.m_our_services & NODE_COMPACT_FILTERS));
3312 if (!supported_filter_type) {
3313 LogDebug(BCLog::NET, "peer requested unsupported block filter type: %d, %s",
3314 static_cast<uint8_t>(filter_type), node.DisconnectMsg());
3315 node.fDisconnect = true;
3316 return false;
3317 }
3318 3319 {
3320 LOCK(cs_main);
3321 stop_index = m_chainman.m_blockman.LookupBlockIndex(stop_hash);
3322 3323 // Check that the stop block exists and the peer would be allowed to fetch it.
3324 if (!stop_index || !BlockRequestAllowed(*stop_index)) {
3325 LogDebug(BCLog::NET, "peer requested invalid block hash: %s, %s",
3326 stop_hash.ToString(), node.DisconnectMsg());
3327 node.fDisconnect = true;
3328 return false;
3329 }
3330 }
3331 3332 uint32_t stop_height = stop_index->nHeight;
3333 if (start_height > stop_height) {
3334 LogDebug(BCLog::NET, "peer sent invalid getcfilters/getcfheaders with "
3335 "start height %d and stop height %d, %s",
3336 start_height, stop_height, node.DisconnectMsg());
3337 node.fDisconnect = true;
3338 return false;
3339 }
3340 if (stop_height - start_height >= max_height_diff) {
3341 LogDebug(BCLog::NET, "peer requested too many cfilters/cfheaders: %d / %d, %s",
3342 stop_height - start_height + 1, max_height_diff, node.DisconnectMsg());
3343 node.fDisconnect = true;
3344 return false;
3345 }
3346 3347 filter_index = GetBlockFilterIndex(filter_type);
3348 if (!filter_index) {
3349 LogDebug(BCLog::NET, "Filter index for supported type %s not found\n", BlockFilterTypeName(filter_type));
3350 return false;
3351 }
3352 3353 return true;
3354 }
3355 3356 void PeerManagerImpl::ProcessGetCFilters(CNode& node, Peer& peer, DataStream& vRecv)
3357 {
3358 uint8_t filter_type_ser;
3359 uint32_t start_height;
3360 uint256 stop_hash;
3361 3362 vRecv >> filter_type_ser >> start_height >> stop_hash;
3363 3364 const BlockFilterType filter_type = static_cast<BlockFilterType>(filter_type_ser);
3365 3366 const CBlockIndex* stop_index;
3367 BlockFilterIndex* filter_index;
3368 if (!PrepareBlockFilterRequest(node, peer, filter_type, start_height, stop_hash,
3369 MAX_GETCFILTERS_SIZE, stop_index, filter_index)) {
3370 return;
3371 }
3372 3373 std::vector<BlockFilter> filters;
3374 if (!filter_index->LookupFilterRange(start_height, stop_index, filters)) {
3375 LogDebug(BCLog::NET, "Failed to find block filter in index: filter_type=%s, start_height=%d, stop_hash=%s\n",
3376 BlockFilterTypeName(filter_type), start_height, stop_hash.ToString());
3377 return;
3378 }
3379 3380 for (const auto& filter : filters) {
3381 MakeAndPushMessage(node, NetMsgType::CFILTER, filter);
3382 }
3383 }
3384 3385 void PeerManagerImpl::ProcessGetCFHeaders(CNode& node, Peer& peer, DataStream& vRecv)
3386 {
3387 uint8_t filter_type_ser;
3388 uint32_t start_height;
3389 uint256 stop_hash;
3390 3391 vRecv >> filter_type_ser >> start_height >> stop_hash;
3392 3393 const BlockFilterType filter_type = static_cast<BlockFilterType>(filter_type_ser);
3394 3395 const CBlockIndex* stop_index;
3396 BlockFilterIndex* filter_index;
3397 if (!PrepareBlockFilterRequest(node, peer, filter_type, start_height, stop_hash,
3398 MAX_GETCFHEADERS_SIZE, stop_index, filter_index)) {
3399 return;
3400 }
3401 3402 uint256 prev_header;
3403 if (start_height > 0) {
3404 const CBlockIndex* const prev_block =
3405 stop_index->GetAncestor(static_cast<int>(start_height - 1));
3406 if (!filter_index->LookupFilterHeader(prev_block, prev_header)) {
3407 LogDebug(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n",
3408 BlockFilterTypeName(filter_type), prev_block->GetBlockHash().ToString());
3409 return;
3410 }
3411 }
3412 3413 std::vector<uint256> filter_hashes;
3414 if (!filter_index->LookupFilterHashRange(start_height, stop_index, filter_hashes)) {
3415 LogDebug(BCLog::NET, "Failed to find block filter hashes in index: filter_type=%s, start_height=%d, stop_hash=%s\n",
3416 BlockFilterTypeName(filter_type), start_height, stop_hash.ToString());
3417 return;
3418 }
3419 3420 MakeAndPushMessage(node, NetMsgType::CFHEADERS,
3421 filter_type_ser,
3422 stop_index->GetBlockHash(),
3423 prev_header,
3424 filter_hashes);
3425 }
3426 3427 void PeerManagerImpl::ProcessGetCFCheckPt(CNode& node, Peer& peer, DataStream& vRecv)
3428 {
3429 uint8_t filter_type_ser;
3430 uint256 stop_hash;
3431 3432 vRecv >> filter_type_ser >> stop_hash;
3433 3434 const BlockFilterType filter_type = static_cast<BlockFilterType>(filter_type_ser);
3435 3436 const CBlockIndex* stop_index;
3437 BlockFilterIndex* filter_index;
3438 if (!PrepareBlockFilterRequest(node, peer, filter_type, /*start_height=*/0, stop_hash,
3439 /*max_height_diff=*/std::numeric_limits<uint32_t>::max(),
3440 stop_index, filter_index)) {
3441 return;
3442 }
3443 3444 std::vector<uint256> headers(stop_index->nHeight / CFCHECKPT_INTERVAL);
3445 3446 // Populate headers.
3447 const CBlockIndex* block_index = stop_index;
3448 for (int i = headers.size() - 1; i >= 0; i--) {
3449 int height = (i + 1) * CFCHECKPT_INTERVAL;
3450 block_index = block_index->GetAncestor(height);
3451 3452 if (!filter_index->LookupFilterHeader(block_index, headers[i])) {
3453 LogDebug(BCLog::NET, "Failed to find block filter header in index: filter_type=%s, block_hash=%s\n",
3454 BlockFilterTypeName(filter_type), block_index->GetBlockHash().ToString());
3455 return;
3456 }
3457 }
3458 3459 MakeAndPushMessage(node, NetMsgType::CFCHECKPT,
3460 filter_type_ser,
3461 stop_index->GetBlockHash(),
3462 headers);
3463 }
3464 3465 void PeerManagerImpl::ProcessBlock(CNode& node, const std::shared_ptr<const CBlock>& block, bool force_processing, bool min_pow_checked)
3466 {
3467 bool new_block{false};
3468 m_chainman.ProcessNewBlock(block, force_processing, min_pow_checked, &new_block);
3469 if (new_block) {
3470 node.m_last_block_time = GetTime<std::chrono::seconds>();
3471 // In case this block came from a different peer than we requested
3472 // from, we can erase the block request now anyway (as we just stored
3473 // this block to disk).
3474 LOCK(cs_main);
3475 RemoveBlockRequest(block->GetHash(), std::nullopt);
3476 } else {
3477 LOCK(cs_main);
3478 mapBlockSource.erase(block->GetHash());
3479 }
3480 }
3481 3482 void PeerManagerImpl::ProcessCompactBlockTxns(CNode& pfrom, Peer& peer, const BlockTransactions& block_transactions)
3483 {
3484 std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
3485 bool fBlockRead{false};
3486 {
3487 LOCK(cs_main);
3488 3489 auto range_flight = mapBlocksInFlight.equal_range(block_transactions.blockhash);
3490 size_t already_in_flight = std::distance(range_flight.first, range_flight.second);
3491 bool requested_block_from_this_peer{false};
3492 3493 // Multimap ensures ordering of outstanding requests. It's either empty or first in line.
3494 bool first_in_flight = already_in_flight == 0 || (range_flight.first->second.first == pfrom.GetId());
3495 3496 while (range_flight.first != range_flight.second) {
3497 auto [node_id, block_it] = range_flight.first->second;
3498 if (node_id == pfrom.GetId() && block_it->partialBlock) {
3499 requested_block_from_this_peer = true;
3500 break;
3501 }
3502 range_flight.first++;
3503 }
3504 3505 if (!requested_block_from_this_peer) {
3506 LogDebug(BCLog::NET, "Peer %d sent us block transactions for block we weren't expecting\n", pfrom.GetId());
3507 return;
3508 }
3509 3510 PartiallyDownloadedBlock& partialBlock = *range_flight.first->second.second->partialBlock;
3511 3512 if (partialBlock.header.IsNull()) {
3513 // It is possible for the header to be empty if a previous call to FillBlock wiped the header, but left
3514 // the PartiallyDownloadedBlock pointer around (i.e. did not call RemoveBlockRequest). In this case, we
3515 // should not call LookupBlockIndex below.
3516 RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId());
3517 Misbehaving(peer, "previous compact block reconstruction attempt failed");
3518 LogDebug(BCLog::NET, "Peer %d sent compact block transactions multiple times", pfrom.GetId());
3519 return;
3520 }
3521 3522 // We should not have gotten this far in compact block processing unless it's attached to a known header
3523 const CBlockIndex* prev_block{Assume(m_chainman.m_blockman.LookupBlockIndex(partialBlock.header.hashPrevBlock))};
3524 ReadStatus status = partialBlock.FillBlock(*pblock, block_transactions.txn,
3525 /*segwit_active=*/DeploymentActiveAfter(prev_block, m_chainman, Consensus::DEPLOYMENT_SEGWIT));
3526 if (status == READ_STATUS_INVALID) {
3527 RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect
3528 Misbehaving(peer, "invalid compact block/non-matching block transactions");
3529 return;
3530 } else if (status == READ_STATUS_FAILED) {
3531 if (first_in_flight) {
3532 // Might have collided, fall back to getdata now :(
3533 // We keep the failed partialBlock to disallow processing another compact block announcement from the same
3534 // peer for the same block. We let the full block download below continue under the same m_downloading_since
3535 // timer.
3536 std::vector<CInv> invs;
3537 invs.emplace_back(MSG_BLOCK | GetFetchFlags(peer), block_transactions.blockhash);
3538 MakeAndPushMessage(pfrom, NetMsgType::GETDATA, invs);
3539 } else {
3540 RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId());
3541 LogDebug(BCLog::NET, "Peer %d sent us a compact block but it failed to reconstruct, waiting on first download to complete\n", pfrom.GetId());
3542 return;
3543 }
3544 } else {
3545 // Block is okay for further processing
3546 RemoveBlockRequest(block_transactions.blockhash, pfrom.GetId()); // it is now an empty pointer
3547 fBlockRead = true;
3548 // mapBlockSource is used for potentially punishing peers and
3549 // updating which peers send us compact blocks, so the race
3550 // between here and cs_main in ProcessNewBlock is fine.
3551 // BIP 152 permits peers to relay compact blocks after validating
3552 // the header only; we should not punish peers if the block turns
3553 // out to be invalid.
3554 mapBlockSource.emplace(block_transactions.blockhash, std::make_pair(pfrom.GetId(), false));
3555 }
3556 } // Don't hold cs_main when we call into ProcessNewBlock
3557 if (fBlockRead) {
3558 // Since we requested this block (it was in mapBlocksInFlight), force it to be processed,
3559 // even if it would not be a candidate for new tip (missing previous block, chain not long enough, etc)
3560 // This bypasses some anti-DoS logic in AcceptBlock (eg to prevent
3561 // disk-space attacks), but this should be safe due to the
3562 // protections in the compact block handler -- see related comment
3563 // in compact block optimistic reconstruction handling.
3564 ProcessBlock(pfrom, pblock, /*force_processing=*/true, /*min_pow_checked=*/true);
3565 }
3566 return;
3567 }
3568 3569 void PeerManagerImpl::LogBlockHeader(const CBlockIndex& index, const CNode& peer, bool via_compact_block) {
3570 // To prevent log spam, this function should only be called after it was determined that a
3571 // header is both new and valid.
3572 //
3573 // These messages are valuable for detecting potential selfish mining behavior;
3574 // if multiple displacing headers are seen near simultaneously across many
3575 // nodes in the network, this might be an indication of selfish mining.
3576 // In addition it can be used to identify peers which send us a header, but
3577 // don't followup with a complete and valid (compact) block.
3578 // Having this log by default when not in IBD ensures broad availability of
3579 // this data in case investigation is merited.
3580 const auto msg = strprintf(
3581 "Saw new %sheader hash=%s height=%d %s",
3582 via_compact_block ? "cmpctblock " : "",
3583 index.GetBlockHash().ToString(),
3584 index.nHeight,
3585 peer.LogPeer()
3586 );
3587 if (m_chainman.IsInitialBlockDownload()) {
3588 LogDebug(BCLog::VALIDATION, "%s", msg);
3589 } else {
3590 LogInfo("%s", msg);
3591 }
3592 }
3593 3594 void PeerManagerImpl::PushPrivateBroadcastTx(CNode& node)
3595 {
3596 Assume(node.IsPrivateBroadcastConn());
3597 3598 const auto opt_tx{m_tx_for_private_broadcast.PickTxForSend(node.GetId(), CService{node.addr})};
3599 if (!opt_tx) {
3600 LogDebug(BCLog::PRIVBROADCAST, "Disconnecting: no more transactions for private broadcast (connected in vain), %s", node.LogPeer());
3601 node.fDisconnect = true;
3602 return;
3603 }
3604 const CTransactionRef& tx{*opt_tx};
3605 3606 LogDebug(BCLog::PRIVBROADCAST, "P2P handshake completed, sending INV for txid=%s%s, %s",
3607 tx->GetHash().ToString(), tx->HasWitness() ? strprintf(", wtxid=%s", tx->GetWitnessHash().ToString()) : "",
3608 node.LogPeer());
3609 3610 MakeAndPushMessage(node, NetMsgType::INV, std::vector<CInv>{{CInv{MSG_TX, tx->GetHash().ToUint256()}}});
3611 }
3612 3613 void PeerManagerImpl::ProcessMessage(Peer& peer, CNode& pfrom, const std::string& msg_type, DataStream& vRecv,
3614 const NodeClock::time_point time_received,
3615 const std::atomic<bool>& interruptMsgProc)
3616 {
3617 AssertLockHeld(g_msgproc_mutex);
3618 3619 LogDebug(BCLog::NET, "received: %s (%u bytes) peer=%d\n", SanitizeString(msg_type), vRecv.size(), pfrom.GetId());
3620 3621 3622 if (msg_type == NetMsgType::VERSION) {
3623 if (pfrom.nVersion != 0) {
3624 LogDebug(BCLog::NET, "redundant version message from peer=%d\n", pfrom.GetId());
3625 return;
3626 }
3627 3628 int64_t nTime;
3629 CService addrMe;
3630 uint64_t nNonce = 1;
3631 ServiceFlags nServices;
3632 int nVersion;
3633 std::string cleanSubVer;
3634 int starting_height = -1;
3635 bool fRelay = true;
3636 3637 vRecv >> nVersion >> Using<CustomUintFormatter<8>>(nServices) >> nTime;
3638 if (nTime < 0) {
3639 nTime = 0;
3640 }
3641 vRecv.ignore(8); // Ignore the addrMe service bits sent by the peer
3642 vRecv >> CNetAddr::V1(addrMe);
3643 if (!pfrom.IsInboundConn() && !pfrom.IsPrivateBroadcastConn())
3644 {
3645 // Overwrites potentially existing services. In contrast to this,
3646 // unvalidated services received via gossip relay in ADDR/ADDRV2
3647 // messages are only ever added but cannot replace existing ones.
3648 m_addrman.SetServices(pfrom.addr, nServices);
3649 }
3650 if (pfrom.ExpectServicesFromConn() && !HasAllDesirableServiceFlags(nServices))
3651 {
3652 LogDebug(BCLog::NET, "peer does not offer the expected services (%08x offered, %08x expected), %s",
3653 nServices,
3654 GetDesirableServiceFlags(nServices),
3655 pfrom.DisconnectMsg());
3656 pfrom.fDisconnect = true;
3657 return;
3658 }
3659 3660 if (nVersion < MIN_PEER_PROTO_VERSION) {
3661 // disconnect from peers older than this proto version
3662 LogDebug(BCLog::NET, "peer using obsolete version %i, %s", nVersion, pfrom.DisconnectMsg());
3663 pfrom.fDisconnect = true;
3664 return;
3665 }
3666 3667 if (!vRecv.empty()) {
3668 // The version message includes information about the sending node which we don't use:
3669 // - 8 bytes (service bits)
3670 // - 16 bytes (ipv6 address)
3671 // - 2 bytes (port)
3672 vRecv.ignore(26);
3673 vRecv >> nNonce;
3674 }
3675 if (!vRecv.empty()) {
3676 std::string strSubVer;
3677 vRecv >> LIMITED_STRING(strSubVer, MAX_SUBVERSION_LENGTH);
3678 cleanSubVer = SanitizeString(strSubVer);
3679 }
3680 if (!vRecv.empty()) {
3681 vRecv >> starting_height;
3682 }
3683 if (!vRecv.empty())
3684 vRecv >> fRelay;
3685 // Disconnect if we connected to ourself
3686 if (pfrom.IsInboundConn() && !m_connman.CheckIncomingNonce(nNonce))
3687 {
3688 LogInfo("connected to self at %s, disconnecting\n", pfrom.addr.ToStringAddrPort());
3689 pfrom.fDisconnect = true;
3690 return;
3691 }
3692 3693 if (pfrom.IsInboundConn() && addrMe.IsRoutable())
3694 {
3695 SeenLocal(addrMe);
3696 }
3697 3698 // Inbound peers send us their version message when they connect.
3699 // We send our version message in response.
3700 if (pfrom.IsInboundConn()) {
3701 PushNodeVersion(pfrom, peer);
3702 }
3703 3704 // Change version
3705 const int greatest_common_version = std::min(nVersion, pfrom.AdvertisedVersion());
3706 pfrom.SetCommonVersion(greatest_common_version);
3707 pfrom.nVersion = nVersion;
3708 3709 pfrom.m_has_all_wanted_services = HasAllDesirableServiceFlags(nServices);
3710 peer.m_their_services = nServices;
3711 pfrom.SetAddrLocal(addrMe);
3712 {
3713 LOCK(pfrom.m_subver_mutex);
3714 pfrom.cleanSubVer = cleanSubVer;
3715 }
3716 3717 // Only initialize the Peer::TxRelay m_relay_txs data structure if:
3718 // - this isn't an outbound block-relay-only connection, and
3719 // - this isn't an outbound feeler connection, and
3720 // - fRelay=true (the peer wishes to receive transaction announcements)
3721 // or we're offering NODE_BLOOM to this peer. NODE_BLOOM means that
3722 // the peer may turn on transaction relay later.
3723 if (!pfrom.IsBlockOnlyConn() &&
3724 !pfrom.IsFeelerConn() &&
3725 (fRelay || (peer.m_our_services & NODE_BLOOM))) {
3726 auto* const tx_relay = peer.SetTxRelay();
3727 {
3728 LOCK(tx_relay->m_bloom_filter_mutex);
3729 tx_relay->m_relay_txs = fRelay; // set to true after we get the first filter* message
3730 }
3731 if (fRelay) pfrom.m_relays_txs = true;
3732 }
3733 3734 const auto mapped_as{m_connman.GetMappedAS(pfrom.addr)};
3735 LogDebug(BCLog::NET, "receive version message: %s: version %d, blocks=%d, us=%s, txrelay=%d, %s%s",
3736 cleanSubVer.empty() ? "<no user agent>" : cleanSubVer, pfrom.nVersion,
3737 starting_height, addrMe.ToStringAddrPort(), fRelay, pfrom.LogPeer(),
3738 (mapped_as ? strprintf(", mapped_as=%d", mapped_as) : ""));
3739 3740 if (pfrom.IsPrivateBroadcastConn()) {
3741 if (fRelay) {
3742 MakeAndPushMessage(pfrom, NetMsgType::VERACK);
3743 } else {
3744 LogDebug(BCLog::PRIVBROADCAST, "Disconnecting: does not support transaction relay (connected in vain), %s",
3745 pfrom.LogPeer());
3746 pfrom.fDisconnect = true;
3747 }
3748 return;
3749 }
3750 3751 if (greatest_common_version >= WTXID_RELAY_VERSION) {
3752 MakeAndPushMessage(pfrom, NetMsgType::WTXIDRELAY);
3753 }
3754 3755 // Signal ADDRv2 support (BIP155).
3756 if (greatest_common_version >= 70016) {
3757 // BIP155 defines addrv2 and sendaddrv2 for all protocol versions, but some
3758 // implementations reject messages they don't know. As a courtesy, don't send
3759 // it to nodes with a version before 70016, as no software is known to support
3760 // BIP155 that doesn't announce at least that protocol version number.
3761 MakeAndPushMessage(pfrom, NetMsgType::SENDADDRV2);
3762 }
3763 3764 if (greatest_common_version >= WTXID_RELAY_VERSION && m_txreconciliation) {
3765 // Per BIP-330, we announce txreconciliation support if:
3766 // - protocol version per the peer's VERSION message supports WTXID_RELAY;
3767 // - transaction relay is supported per the peer's VERSION message
3768 // - this is not a block-relay-only connection and not a feeler
3769 // - this is not an addr fetch connection;
3770 // - we are not in -blocksonly mode.
3771 const auto* tx_relay = peer.GetTxRelay();
3772 if (tx_relay && WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs) &&
3773 !pfrom.IsAddrFetchConn() && !m_opts.ignore_incoming_txs) {
3774 const uint64_t recon_salt = m_txreconciliation->PreRegisterPeer(pfrom.GetId());
3775 MakeAndPushMessage(pfrom, NetMsgType::SENDTXRCNCL,
3776 TXRECONCILIATION_VERSION, recon_salt);
3777 }
3778 }
3779 3780 if (greatest_common_version >= FEATURE_VERSION) {
3781 // announce supported features
3782 // MakeAndPushFeature(pfrom, NetMsgFeature::FOO, uint32_t{1});
3783 }
3784 3785 MakeAndPushMessage(pfrom, NetMsgType::VERACK);
3786 3787 // Potentially mark this peer as a preferred download peer.
3788 {
3789 LOCK(cs_main);
3790 CNodeState* state = State(pfrom.GetId());
3791 state->fPreferredDownload = (!pfrom.IsInboundConn() || pfrom.HasPermission(NetPermissionFlags::NoBan)) && !pfrom.IsAddrFetchConn() && CanServeBlocks(peer);
3792 m_num_preferred_download_peers += state->fPreferredDownload;
3793 }
3794 3795 // Attempt to initialize address relay for outbound peers and use result
3796 // to decide whether to send GETADDR, so that we don't send it to
3797 // inbound, feelers, or outbound block-relay-only peers.
3798 bool send_getaddr{false};
3799 if (!pfrom.IsInboundConn()) {
3800 send_getaddr = SetupAddressRelay(pfrom, peer);
3801 }
3802 if (send_getaddr) {
3803 // Do a one-time address fetch to help populate/update our addrman.
3804 // If we're starting up for the first time, our addrman may be pretty
3805 // empty, so this mechanism is important to help us connect to the network.
3806 // We skip this for block-relay-only peers. We want to avoid
3807 // potentially leaking addr information and we do not want to
3808 // indicate to the peer that we will participate in addr relay.
3809 MakeAndPushMessage(pfrom, NetMsgType::GETADDR);
3810 peer.m_getaddr_sent = true;
3811 // When requesting a getaddr, accept an additional MAX_ADDR_TO_SEND addresses in response
3812 // (bypassing the MAX_ADDR_PROCESSING_TOKEN_BUCKET limit).
3813 peer.m_addr_token_bucket += MAX_ADDR_TO_SEND;
3814 }
3815 3816 if (!pfrom.IsInboundConn()) {
3817 // For non-inbound connections, we update the addrman to record
3818 // connection success so that addrman will have an up-to-date
3819 // notion of which peers are online and available.
3820 //
3821 // While we strive to not leak information about block-relay-only
3822 // connections via the addrman, not moving an address to the tried
3823 // table is also potentially detrimental because new-table entries
3824 // are subject to eviction in the event of addrman collisions. We
3825 // mitigate the information-leak by never calling
3826 // AddrMan::Connected() on block-relay-only peers; see
3827 // FinalizeNode().
3828 //
3829 // This moves an address from New to Tried table in Addrman,
3830 // resolves tried-table collisions, etc.
3831 m_addrman.Good(pfrom.addr);
3832 }
3833 3834 peer.m_time_offset = NodeSeconds{std::chrono::seconds{nTime}} - Now<NodeSeconds>();
3835 if (!pfrom.IsInboundConn()) {
3836 // Don't use timedata samples from inbound peers to make it
3837 // harder for others to create false warnings about our clock being out of sync.
3838 m_outbound_time_offsets.Add(peer.m_time_offset);
3839 m_outbound_time_offsets.WarnIfOutOfSync();
3840 }
3841 3842 // If the peer is old enough to have the old alert system, send it the final alert.
3843 if (greatest_common_version <= 70012) {
3844 constexpr auto finalAlert{"60010000000000000000000000ffffff7f00000000ffffff7ffeffff7f01ffffff7f00000000ffffff7f00ffffff7f002f555247454e543a20416c657274206b657920636f6d70726f6d697365642c2075706772616465207265717569726564004630440220653febd6410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3abd5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fecaae66ecf689bf71b50"_hex};
3845 MakeAndPushMessage(pfrom, "alert", finalAlert);
3846 }
3847 3848 // Feeler connections exist only to verify if address is online.
3849 if (pfrom.IsFeelerConn()) {
3850 LogDebug(BCLog::NET, "feeler connection completed, %s", pfrom.DisconnectMsg());
3851 pfrom.fDisconnect = true;
3852 }
3853 return;
3854 }
3855 3856 if (pfrom.nVersion == 0) {
3857 // Must have a version message before anything else
3858 LogDebug(BCLog::NET, "non-version message before version handshake. Message \"%s\" from peer=%d\n", SanitizeString(msg_type), pfrom.GetId());
3859 return;
3860 }
3861 3862 if (msg_type == NetMsgType::VERACK) {
3863 if (pfrom.fSuccessfullyConnected) {
3864 LogDebug(BCLog::NET, "ignoring redundant verack message from peer=%d\n", pfrom.GetId());
3865 return;
3866 }
3867 3868 auto new_peer_msg = [&]() {
3869 const auto mapped_as{m_connman.GetMappedAS(pfrom.addr)};
3870 return strprintf("New %s peer connected: transport: %s, version: %d, %s%s",
3871 pfrom.ConnectionTypeAsString(),
3872 TransportTypeAsString(pfrom.m_transport->GetInfo().transport_type),
3873 pfrom.nVersion.load(), pfrom.LogPeer(),
3874 (mapped_as ? strprintf(", mapped_as=%d", mapped_as) : ""));
3875 };
3876 3877 // Log successful connections unconditionally for outbound, but not for inbound as those
3878 // can be triggered by an attacker at high rate.
3879 if (pfrom.IsInboundConn()) {
3880 LogDebug(BCLog::NET, "%s", new_peer_msg());
3881 } else {
3882 LogInfo("%s", new_peer_msg());
3883 }
3884 3885 if (auto tx_relay = peer.GetTxRelay()) {
3886 // `TxRelay::m_tx_inventory_to_send` must be empty before the
3887 // version handshake is completed as
3888 // `TxRelay::m_next_inv_send_time` is first initialised in
3889 // `SendMessages` after the verack is received. Any transactions
3890 // received during the version handshake would otherwise
3891 // immediately be advertised without random delay, potentially
3892 // leaking the time of arrival to a spy.
3893 Assume(WITH_LOCK(
3894 tx_relay->m_tx_inventory_mutex,
3895 return tx_relay->m_tx_inventory_to_send.empty() &&
3896 tx_relay->m_next_inv_send_time == 0s));
3897 }
3898 3899 if (pfrom.IsPrivateBroadcastConn()) {
3900 pfrom.fSuccessfullyConnected = true;
3901 // The peer may intend to later send us NetMsgType::FEEFILTER limiting
3902 // cheap transactions, but we don't wait for that and thus we may send
3903 // them a transaction below their threshold. This is ok because this
3904 // relay logic is designed to work even in cases when the peer drops
3905 // the transaction (due to it being too cheap, or for other reasons).
3906 PushPrivateBroadcastTx(pfrom);
3907 return;
3908 }
3909 3910 if (pfrom.GetCommonVersion() >= SHORT_IDS_BLOCKS_VERSION) {
3911 // Tell our peer we are willing to provide version 2 cmpctblocks.
3912 // However, we do not request new block announcements using
3913 // cmpctblock messages.
3914 // We send this to non-NODE NETWORK peers as well, because
3915 // they may wish to request compact blocks from us
3916 MakeAndPushMessage(pfrom, NetMsgType::SENDCMPCT, /*high_bandwidth=*/false, /*version=*/CMPCTBLOCKS_VERSION);
3917 }
3918 3919 if (m_txreconciliation) {
3920 if (!peer.m_wtxid_relay || !m_txreconciliation->IsPeerRegistered(pfrom.GetId())) {
3921 // We could have optimistically pre-registered/registered the peer. In that case,
3922 // we should forget about the reconciliation state here if this wasn't followed
3923 // by WTXIDRELAY (since WTXIDRELAY can't be announced later).
3924 m_txreconciliation->ForgetPeer(pfrom.GetId());
3925 }
3926 }
3927 3928 {
3929 LOCK2(::cs_main, m_tx_download_mutex);
3930 const CNodeState* state = State(pfrom.GetId());
3931 m_txdownloadman.ConnectedPeer(pfrom.GetId(), node::TxDownloadConnectionInfo {
3932 .m_preferred = state->fPreferredDownload,
3933 .m_relay_permissions = pfrom.HasPermission(NetPermissionFlags::Relay),
3934 .m_wtxid_relay = peer.m_wtxid_relay,
3935 });
3936 }
3937 3938 pfrom.fSuccessfullyConnected = true;
3939 return;
3940 }
3941 3942 if (msg_type == NetMsgType::SENDHEADERS) {
3943 peer.m_prefers_headers = true;
3944 return;
3945 }
3946 3947 if (msg_type == NetMsgType::SENDCMPCT) {
3948 uint8_t sendcmpct_hb{0};
3949 uint64_t sendcmpct_version{0};
3950 vRecv >> sendcmpct_hb >> sendcmpct_version;
3951 3952 // BIP152: the first integer is interpreted as a boolean and MUST have a
3953 // value of either 1 or 0.
3954 if (sendcmpct_hb > 1) {
3955 Misbehaving(peer, "invalid sendcmpct announce field");
3956 return;
3957 }
3958 3959 // Only support compact block relay with witnesses
3960 if (sendcmpct_version != CMPCTBLOCKS_VERSION) return;
3961 3962 LOCK(cs_main);
3963 CNodeState* nodestate = State(pfrom.GetId());
3964 nodestate->m_provides_cmpctblocks = true;
3965 nodestate->m_requested_hb_cmpctblocks = sendcmpct_hb;
3966 // save whether peer selects us as BIP152 high-bandwidth peer
3967 // (receiving sendcmpct(1) signals high-bandwidth, sendcmpct(0) low-bandwidth)
3968 pfrom.m_bip152_highbandwidth_from = sendcmpct_hb;
3969 return;
3970 }
3971 3972 // BIP339 defines feature negotiation of wtxidrelay, which must happen between
3973 // VERSION and VERACK to avoid relay problems from switching after a connection is up.
3974 if (msg_type == NetMsgType::WTXIDRELAY) {
3975 if (pfrom.fSuccessfullyConnected) {
3976 // Disconnect peers that send a wtxidrelay message after VERACK.
3977 LogDebug(BCLog::NET, "wtxidrelay received after verack, %s", pfrom.DisconnectMsg());
3978 pfrom.fDisconnect = true;
3979 return;
3980 }
3981 if (pfrom.GetCommonVersion() >= WTXID_RELAY_VERSION) {
3982 if (!peer.m_wtxid_relay) {
3983 peer.m_wtxid_relay = true;
3984 m_wtxid_relay_peers++;
3985 } else {
3986 LogDebug(BCLog::NET, "ignoring duplicate wtxidrelay from peer=%d\n", pfrom.GetId());
3987 }
3988 } else {
3989 LogDebug(BCLog::NET, "ignoring wtxidrelay due to old common version=%d from peer=%d\n", pfrom.GetCommonVersion(), pfrom.GetId());
3990 }
3991 return;
3992 }
3993 3994 // BIP155 defines feature negotiation of addrv2 and sendaddrv2, which must happen
3995 // between VERSION and VERACK.
3996 if (msg_type == NetMsgType::SENDADDRV2) {
3997 if (pfrom.fSuccessfullyConnected) {
3998 // Disconnect peers that send a SENDADDRV2 message after VERACK.
3999 LogDebug(BCLog::NET, "sendaddrv2 received after verack, %s", pfrom.DisconnectMsg());
4000 pfrom.fDisconnect = true;
4001 return;
4002 }
4003 peer.m_wants_addrv2 = true;
4004 return;
4005 }
4006 4007 if (msg_type == NetMsgType::FEATURE) {
4008 if (pfrom.fSuccessfullyConnected) {
4009 // Disconnect peers that send a FEATURE message after VERACK.
4010 LogDebug(BCLog::NET, "feature received after verack, %s", pfrom.DisconnectMsg());
4011 pfrom.fDisconnect = true;
4012 return;
4013 } else if (pfrom.GetCommonVersion() < FEATURE_VERSION) {
4014 // Disconnect peers that send a FEATURE message without valid version negotiation.
4015 LogDebug(BCLog::NET, "feature received with incompatible version %d, %s", pfrom.GetCommonVersion(), pfrom.DisconnectMsg());
4016 pfrom.fDisconnect = true;
4017 return;
4018 }
4019 4020 std::string feature_id;
4021 DataStream feature_data;
4022 try {
4023 vRecv >> LIMITED_STRING(feature_id, MAX_FEATUREID_LENGTH);
4024 std::vector<unsigned char> feature_data_vec;
4025 vRecv >> LIMITED_VECTOR(feature_data_vec, MAX_FEATUREDATA_LENGTH);
4026 feature_data = DataStream(feature_data_vec);
4027 } catch (const std::exception&) {
4028 feature_id.clear(); // use empty feature_id as error indicator
4029 }
4030 if (feature_id.size() < 4 || !vRecv.empty()) {
4031 LogDebug(BCLog::NET, "invalid feature payload, %s", pfrom.DisconnectMsg());
4032 pfrom.fDisconnect = true;
4033 return;
4034 }
4035 4036 // if (feature_id == NetMsgFeature::FOO) {
4037 // ...
4038 // return;
4039 // }
4040 4041 // ignore unknown feature_id
4042 LogDebug(BCLog::NET, "unknown feature advertised: %s", SanitizeString(feature_id));
4043 return;
4044 }
4045 4046 // Received from a peer demonstrating readiness to announce transactions via reconciliations.
4047 // This feature negotiation must happen between VERSION and VERACK to avoid relay problems
4048 // from switching announcement protocols after the connection is up.
4049 if (msg_type == NetMsgType::SENDTXRCNCL) {
4050 if (!m_txreconciliation) {
4051 LogDebug(BCLog::NET, "sendtxrcncl from peer=%d ignored, as our node does not have txreconciliation enabled\n", pfrom.GetId());
4052 return;
4053 }
4054 4055 if (pfrom.fSuccessfullyConnected) {
4056 LogDebug(BCLog::NET, "sendtxrcncl received after verack, %s", pfrom.DisconnectMsg());
4057 pfrom.fDisconnect = true;
4058 return;
4059 }
4060 4061 // Peer must not offer us reconciliations if we specified no tx relay support in VERSION.
4062 if (RejectIncomingTxs(pfrom)) {
4063 LogDebug(BCLog::NET, "sendtxrcncl received to which we indicated no tx relay, %s", pfrom.DisconnectMsg());
4064 pfrom.fDisconnect = true;
4065 return;
4066 }
4067 4068 // Peer must not offer us reconciliations if they specified no tx relay support in VERSION.
4069 // This flag might also be false in other cases, but the RejectIncomingTxs check above
4070 // eliminates them, so that this flag fully represents what we are looking for.
4071 const auto* tx_relay = peer.GetTxRelay();
4072 if (!tx_relay || !WITH_LOCK(tx_relay->m_bloom_filter_mutex, return tx_relay->m_relay_txs)) {
4073 LogDebug(BCLog::NET, "sendtxrcncl received which indicated no tx relay to us, %s", pfrom.DisconnectMsg());
4074 pfrom.fDisconnect = true;
4075 return;
4076 }
4077 4078 uint32_t peer_txreconcl_version;
4079 uint64_t remote_salt;
4080 vRecv >> peer_txreconcl_version >> remote_salt;
4081 4082 const ReconciliationRegisterResult result = m_txreconciliation->RegisterPeer(pfrom.GetId(), pfrom.IsInboundConn(),
4083 peer_txreconcl_version, remote_salt);
4084 switch (result) {
4085 case ReconciliationRegisterResult::NOT_FOUND:
4086 LogDebug(BCLog::NET, "Ignore unexpected txreconciliation signal from peer=%d\n", pfrom.GetId());
4087 break;
4088 case ReconciliationRegisterResult::SUCCESS:
4089 break;
4090 case ReconciliationRegisterResult::ALREADY_REGISTERED:
4091 LogDebug(BCLog::NET, "txreconciliation protocol violation (sendtxrcncl received from already registered peer), %s", pfrom.DisconnectMsg());
4092 pfrom.fDisconnect = true;
4093 return;
4094 case ReconciliationRegisterResult::PROTOCOL_VIOLATION:
4095 LogDebug(BCLog::NET, "txreconciliation protocol violation, %s", pfrom.DisconnectMsg());
4096 pfrom.fDisconnect = true;
4097 return;
4098 }
4099 return;
4100 }
4101 4102 if (!pfrom.fSuccessfullyConnected) {
4103 LogDebug(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId());
4104 return;
4105 }
4106 4107 if (pfrom.IsPrivateBroadcastConn()) {
4108 if (msg_type != NetMsgType::PONG && msg_type != NetMsgType::GETDATA) {
4109 LogDebug(BCLog::PRIVBROADCAST, "Ignoring incoming message '%s', %s", msg_type, pfrom.LogPeer());
4110 return;
4111 }
4112 }
4113 4114 if (msg_type == NetMsgType::ADDR || msg_type == NetMsgType::ADDRV2) {
4115 const auto ser_params{
4116 msg_type == NetMsgType::ADDRV2 ?
4117 // Set V2 param so that the CNetAddr and CAddress
4118 // unserialize methods know that an address in v2 format is coming.
4119 CAddress::V2_NETWORK :
4120 CAddress::V1_NETWORK,
4121 };
4122 4123 std::vector<CAddress> vAddr;
4124 vRecv >> ser_params(vAddr);
4125 ProcessAddrs(msg_type, pfrom, peer, std::move(vAddr), interruptMsgProc);
4126 return;
4127 }
4128 4129 if (msg_type == NetMsgType::INV) {
4130 std::vector<CInv> vInv;
4131 vRecv >> vInv;
4132 if (vInv.size() > MAX_INV_SZ)
4133 {
4134 Misbehaving(peer, strprintf("inv message size = %u", vInv.size()));
4135 return;
4136 }
4137 4138 const bool reject_tx_invs{RejectIncomingTxs(pfrom)};
4139 4140 LOCK2(cs_main, m_tx_download_mutex);
4141 4142 const auto current_time{GetTime<std::chrono::microseconds>()};
4143 uint256* best_block{nullptr};
4144 4145 for (CInv& inv : vInv) {
4146 if (interruptMsgProc) return;
4147 4148 // Ignore INVs that don't match wtxidrelay setting.
4149 // Note that orphan parent fetching always uses MSG_TX GETDATAs regardless of the wtxidrelay setting.
4150 // This is fine as no INV messages are involved in that process.
4151 if (peer.m_wtxid_relay) {
4152 if (inv.IsMsgTx()) continue;
4153 } else {
4154 if (inv.IsMsgWtx()) continue;
4155 }
4156 4157 if (inv.IsMsgBlk()) {
4158 const bool fAlreadyHave = AlreadyHaveBlock(inv.hash);
4159 LogDebug(BCLog::NET, "got inv: %s %s peer=%d", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId());
4160 4161 UpdateBlockAvailability(pfrom.GetId(), inv.hash);
4162 if (!fAlreadyHave && !m_chainman.m_blockman.LoadingBlocks() && !IsBlockRequested(inv.hash)) {
4163 // Headers-first is the primary method of announcement on
4164 // the network. If a node fell back to sending blocks by
4165 // inv, it may be for a re-org, or because we haven't
4166 // completed initial headers sync. The final block hash
4167 // provided should be the highest, so send a getheaders and
4168 // then fetch the blocks we need to catch up.
4169 best_block = &inv.hash;
4170 }
4171 } else if (inv.IsGenTxMsg()) {
4172 if (reject_tx_invs) {
4173 LogDebug(BCLog::NET, "transaction (%s) inv sent in violation of protocol, %s", inv.hash.ToString(), pfrom.DisconnectMsg());
4174 pfrom.fDisconnect = true;
4175 return;
4176 }
4177 const GenTxid gtxid = ToGenTxid(inv);
4178 AddKnownTx(peer, inv.hash);
4179 4180 if (!m_chainman.IsInitialBlockDownload()) {
4181 const bool fAlreadyHave{m_txdownloadman.AddTxAnnouncement(pfrom.GetId(), gtxid, current_time)};
4182 LogDebug(BCLog::NET, "got inv: %s %s peer=%d", inv.ToString(), fAlreadyHave ? "have" : "new", pfrom.GetId());
4183 }
4184 } else {
4185 LogDebug(BCLog::NET, "Unknown inv type \"%s\" received from peer=%d\n", inv.ToString(), pfrom.GetId());
4186 }
4187 }
4188 4189 if (best_block != nullptr) {
4190 // If we haven't started initial headers-sync with this peer, then
4191 // consider sending a getheaders now. On initial startup, there's a
4192 // reliability vs bandwidth tradeoff, where we are only trying to do
4193 // initial headers sync with one peer at a time, with a long
4194 // timeout (at which point, if the sync hasn't completed, we will
4195 // disconnect the peer and then choose another). In the meantime,
4196 // as new blocks are found, we are willing to add one new peer per
4197 // block to sync with as well, to sync quicker in the case where
4198 // our initial peer is unresponsive (but less bandwidth than we'd
4199 // use if we turned on sync with all peers).
4200 CNodeState& state{*Assert(State(pfrom.GetId()))};
4201 if (state.fSyncStarted || (!peer.m_inv_triggered_getheaders_before_sync && *best_block != m_last_block_inv_triggering_headers_sync)) {
4202 if (MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), peer)) {
4203 LogDebug(BCLog::NET, "getheaders (%d) %s to peer=%d\n",
4204 m_chainman.m_best_header->nHeight, best_block->ToString(),
4205 pfrom.GetId());
4206 }
4207 if (!state.fSyncStarted) {
4208 peer.m_inv_triggered_getheaders_before_sync = true;
4209 // Update the last block hash that triggered a new headers
4210 // sync, so that we don't turn on headers sync with more
4211 // than 1 new peer every new block.
4212 m_last_block_inv_triggering_headers_sync = *best_block;
4213 }
4214 }
4215 }
4216 4217 return;
4218 }
4219 4220 if (msg_type == NetMsgType::GETDATA) {
4221 std::vector<CInv> vInv;
4222 vRecv >> vInv;
4223 if (vInv.size() > MAX_INV_SZ)
4224 {
4225 Misbehaving(peer, strprintf("getdata message size = %u", vInv.size()));
4226 return;
4227 }
4228 4229 LogDebug(BCLog::NET, "received getdata (%u invsz) peer=%d\n", vInv.size(), pfrom.GetId());
4230 4231 if (vInv.size() > 0) {
4232 LogDebug(BCLog::NET, "received getdata for: %s peer=%d\n", vInv[0].ToString(), pfrom.GetId());
4233 }
4234 4235 if (pfrom.IsPrivateBroadcastConn()) {
4236 const auto pushed_tx_opt{m_tx_for_private_broadcast.GetTxForNode(pfrom.GetId())};
4237 if (!pushed_tx_opt) {
4238 LogDebug(BCLog::PRIVBROADCAST, "Disconnecting: got GETDATA without sending an INV, %s",
4239 pfrom.LogPeer());
4240 pfrom.fDisconnect = true;
4241 return;
4242 }
4243 4244 const CTransactionRef& pushed_tx{*pushed_tx_opt};
4245 4246 // The GETDATA request must contain exactly one inv and it must be for the transaction
4247 // that we INVed to the peer earlier.
4248 if (vInv.size() == 1 && vInv[0].IsMsgTx() && vInv[0].hash == pushed_tx->GetHash().ToUint256()) {
4249 4250 MakeAndPushMessage(pfrom, NetMsgType::TX, TX_WITH_WITNESS(*pushed_tx));
4251 4252 peer.m_ping_queued = true; // Ensure a ping will be sent: mimic a request via RPC.
4253 MaybeSendPing(pfrom, peer, NodeClock::now());
4254 } else {
4255 LogDebug(BCLog::PRIVBROADCAST, "Disconnecting: got an unexpected GETDATA message, %s",
4256 pfrom.LogPeer());
4257 pfrom.fDisconnect = true;
4258 }
4259 return;
4260 }
4261 4262 {
4263 LOCK(peer.m_getdata_requests_mutex);
4264 peer.m_getdata_requests.insert(peer.m_getdata_requests.end(), vInv.begin(), vInv.end());
4265 ProcessGetData(pfrom, peer, interruptMsgProc);
4266 }
4267 4268 return;
4269 }
4270 4271 if (msg_type == NetMsgType::GETBLOCKS) {
4272 CBlockLocator locator;
4273 uint256 hashStop;
4274 vRecv >> locator >> hashStop;
4275 4276 if (locator.vHave.size() > MAX_LOCATOR_SZ) {
4277 LogDebug(BCLog::NET, "getblocks locator size %lld > %d, %s", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.DisconnectMsg());
4278 pfrom.fDisconnect = true;
4279 return;
4280 }
4281 4282 // We might have announced the currently-being-connected tip using a
4283 // compact block, which resulted in the peer sending a getblocks
4284 // request, which we would otherwise respond to without the new block.
4285 // To avoid this situation we simply verify that we are on our best
4286 // known chain now. This is super overkill, but we handle it better
4287 // for getheaders requests, and there are no known nodes which support
4288 // compact blocks but still use getblocks to request blocks.
4289 {
4290 std::shared_ptr<const CBlock> a_recent_block;
4291 {
4292 LOCK(m_most_recent_block_mutex);
4293 a_recent_block = m_most_recent_block;
4294 }
4295 BlockValidationState state;
4296 if (!m_chainman.ActiveChainstate().ActivateBestChain(state, a_recent_block)) {
4297 LogDebug(BCLog::NET, "failed to activate chain (%s)\n", state.ToString());
4298 }
4299 }
4300 4301 LOCK(cs_main);
4302 4303 // Find the last block the caller has in the main chain
4304 const CBlockIndex* pindex = m_chainman.ActiveChainstate().FindForkInGlobalIndex(locator);
4305 4306 // Send the rest of the chain
4307 if (pindex)
4308 pindex = m_chainman.ActiveChain().Next(*pindex);
4309 int nLimit = 500;
4310 LogDebug(BCLog::NET, "getblocks %d to %s limit %d from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), nLimit, pfrom.GetId());
4311 for (; pindex; pindex = m_chainman.ActiveChain().Next(*pindex))
4312 {
4313 if (pindex->GetBlockHash() == hashStop)
4314 {
4315 LogDebug(BCLog::NET, " getblocks stopping at %d %s", pindex->nHeight, pindex->GetBlockHash().ToString());
4316 break;
4317 }
4318 // If pruning, don't inv blocks unless we have on disk and are likely to still have
4319 // for some reasonable time window (1 hour) that block relay might require.
4320 const int nPrunedBlocksLikelyToHave = MIN_BLOCKS_TO_KEEP - 3600 / m_chainparams.GetConsensus().nPowTargetSpacing;
4321 if (m_chainman.m_blockman.IsPruneMode() && (!(pindex->nStatus & BLOCK_HAVE_DATA) || pindex->nHeight <= m_chainman.ActiveChain().Tip()->nHeight - nPrunedBlocksLikelyToHave)) {
4322 LogDebug(BCLog::NET, " getblocks stopping, pruned or too old block at %d %s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
4323 break;
4324 }
4325 WITH_LOCK(peer.m_block_inv_mutex, peer.m_blocks_for_inv_relay.push_back(pindex->GetBlockHash()));
4326 if (--nLimit <= 0) {
4327 // When this block is requested, we'll send an inv that'll
4328 // trigger the peer to getblocks the next batch of inventory.
4329 LogDebug(BCLog::NET, " getblocks stopping at limit %d %s", pindex->nHeight, pindex->GetBlockHash().ToString());
4330 WITH_LOCK(peer.m_block_inv_mutex, {peer.m_continuation_block = pindex->GetBlockHash();});
4331 break;
4332 }
4333 }
4334 return;
4335 }
4336 4337 if (msg_type == NetMsgType::GETBLOCKTXN) {
4338 BlockTransactionsRequest req;
4339 vRecv >> req;
4340 // Verify differential encoding invariant: indexes must be strictly increasing
4341 // DifferenceFormatter should guarantee this property during deserialization
4342 for (size_t i = 1; i < req.indexes.size(); ++i) {
4343 Assume(req.indexes[i] > req.indexes[i-1]);
4344 }
4345 4346 std::shared_ptr<const CBlock> recent_block;
4347 {
4348 LOCK(m_most_recent_block_mutex);
4349 if (m_most_recent_block_hash == req.blockhash)
4350 recent_block = m_most_recent_block;
4351 // Unlock m_most_recent_block_mutex to avoid cs_main lock inversion
4352 }
4353 if (recent_block) {
4354 SendBlockTransactions(pfrom, peer, *recent_block, req);
4355 return;
4356 }
4357 4358 FlatFilePos block_pos{};
4359 {
4360 LOCK(cs_main);
4361 4362 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(req.blockhash);
4363 if (!pindex || !(pindex->nStatus & BLOCK_HAVE_DATA)) {
4364 LogDebug(BCLog::NET, "Peer %d sent us a getblocktxn for a block we don't have\n", pfrom.GetId());
4365 return;
4366 }
4367 4368 if (pindex->nHeight >= m_chainman.ActiveChain().Height() - MAX_BLOCKTXN_DEPTH) {
4369 block_pos = pindex->GetBlockPos();
4370 }
4371 }
4372 4373 if (!block_pos.IsNull()) {
4374 CBlock block;
4375 const bool ret{m_chainman.m_blockman.ReadBlock(block, block_pos, req.blockhash)};
4376 // If height is above MAX_BLOCKTXN_DEPTH then this block cannot get
4377 // pruned after we release cs_main above, so this read should never fail.
4378 assert(ret);
4379 4380 SendBlockTransactions(pfrom, peer, block, req);
4381 return;
4382 }
4383 4384 // If an older block is requested (should never happen in practice,
4385 // but can happen in tests) send a block response instead of a
4386 // blocktxn response. Sending a full block response instead of a
4387 // small blocktxn response is preferable in the case where a peer
4388 // might maliciously send lots of getblocktxn requests to trigger
4389 // expensive disk reads, because it will require the peer to
4390 // actually receive all the data read from disk over the network.
4391 LogDebug(BCLog::NET, "Peer %d sent us a getblocktxn for a block > %i deep\n", pfrom.GetId(), MAX_BLOCKTXN_DEPTH);
4392 CInv inv{MSG_WITNESS_BLOCK, req.blockhash};
4393 WITH_LOCK(peer.m_getdata_requests_mutex, peer.m_getdata_requests.push_back(inv));
4394 // The message processing loop will go around again (without pausing) and we'll respond then
4395 return;
4396 }
4397 4398 if (msg_type == NetMsgType::GETHEADERS) {
4399 CBlockLocator locator;
4400 uint256 hashStop;
4401 vRecv >> locator >> hashStop;
4402 4403 if (locator.vHave.size() > MAX_LOCATOR_SZ) {
4404 LogDebug(BCLog::NET, "getheaders locator size %lld > %d, %s", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.DisconnectMsg());
4405 pfrom.fDisconnect = true;
4406 return;
4407 }
4408 4409 if (m_chainman.m_blockman.LoadingBlocks()) {
4410 LogDebug(BCLog::NET, "Ignoring getheaders from peer=%d while importing/reindexing\n", pfrom.GetId());
4411 return;
4412 }
4413 4414 LOCK(cs_main);
4415 4416 // Don't serve headers from our active chain until our chainwork is at least
4417 // the minimum chain work. This prevents us from starting a low-work headers
4418 // sync that will inevitably be aborted by our peer.
4419 if (m_chainman.ActiveTip() == nullptr ||
4420 (m_chainman.ActiveTip()->nChainWork < m_chainman.MinimumChainWork() && !pfrom.HasPermission(NetPermissionFlags::Download))) {
4421 LogDebug(BCLog::NET, "Ignoring getheaders from peer=%d because active chain has too little work; sending empty response\n", pfrom.GetId());
4422 // Just respond with an empty headers message, to tell the peer to
4423 // go away but not treat us as unresponsive.
4424 MakeAndPushMessage(pfrom, NetMsgType::HEADERS, std::vector<CBlockHeader>());
4425 return;
4426 }
4427 4428 CNodeState *nodestate = State(pfrom.GetId());
4429 const CBlockIndex* pindex = nullptr;
4430 if (locator.IsNull())
4431 {
4432 // If locator is null, return the hashStop block
4433 pindex = m_chainman.m_blockman.LookupBlockIndex(hashStop);
4434 if (!pindex) {
4435 return;
4436 }
4437 if (!BlockRequestAllowed(*pindex)) {
4438 LogDebug(BCLog::NET, "%s: ignoring request from peer=%i for old block header that isn't in the main chain\n", __func__, pfrom.GetId());
4439 return;
4440 }
4441 }
4442 else
4443 {
4444 // Find the last block the caller has in the main chain
4445 pindex = m_chainman.ActiveChainstate().FindForkInGlobalIndex(locator);
4446 if (pindex)
4447 pindex = m_chainman.ActiveChain().Next(*pindex);
4448 }
4449 4450 // we must use CBlocks, as CBlockHeaders won't include the 0x00 nTx count at the end
4451 std::vector<CBlock> vHeaders;
4452 int nLimit = m_opts.max_headers_result;
4453 LogDebug(BCLog::NET, "getheaders %d to %s from peer=%d\n", (pindex ? pindex->nHeight : -1), hashStop.IsNull() ? "end" : hashStop.ToString(), pfrom.GetId());
4454 for (; pindex; pindex = m_chainman.ActiveChain().Next(*pindex))
4455 {
4456 vHeaders.emplace_back(pindex->GetBlockHeader());
4457 if (--nLimit <= 0 || pindex->GetBlockHash() == hashStop)
4458 break;
4459 }
4460 // pindex can be nullptr either if we sent m_chainman.ActiveChain().Tip() OR
4461 // if our peer has m_chainman.ActiveChain().Tip() (and thus we are sending an empty
4462 // headers message). In both cases it's safe to update
4463 // pindexBestHeaderSent to be our tip.
4464 //
4465 // It is important that we simply reset the BestHeaderSent value here,
4466 // and not max(BestHeaderSent, newHeaderSent). We might have announced
4467 // the currently-being-connected tip using a compact block, which
4468 // resulted in the peer sending a headers request, which we respond to
4469 // without the new block. By resetting the BestHeaderSent, we ensure we
4470 // will re-announce the new block via headers (or compact blocks again)
4471 // in the SendMessages logic.
4472 nodestate->pindexBestHeaderSent = pindex ? pindex : m_chainman.ActiveChain().Tip();
4473 MakeAndPushMessage(pfrom, NetMsgType::HEADERS, TX_WITH_WITNESS(vHeaders));
4474 return;
4475 }
4476 4477 if (msg_type == NetMsgType::TX) {
4478 if (RejectIncomingTxs(pfrom)) {
4479 LogDebug(BCLog::NET, "transaction sent in violation of protocol, %s", pfrom.DisconnectMsg());
4480 pfrom.fDisconnect = true;
4481 return;
4482 }
4483 4484 // Stop processing the transaction early if we are still in IBD since we don't
4485 // have enough information to validate it yet. Sending unsolicited transactions
4486 // is not considered a protocol violation, so don't punish the peer.
4487 if (m_chainman.IsInitialBlockDownload()) return;
4488 4489 CTransactionRef ptx;
4490 vRecv >> TX_WITH_WITNESS(ptx);
4491 4492 const Txid& txid = ptx->GetHash();
4493 const Wtxid& wtxid = ptx->GetWitnessHash();
4494 4495 const uint256& hash = peer.m_wtxid_relay ? wtxid.ToUint256() : txid.ToUint256();
4496 AddKnownTx(peer, hash);
4497 4498 if (const auto num_broadcasted{m_tx_for_private_broadcast.Remove(ptx)}) {
4499 LogDebug(BCLog::PRIVBROADCAST, "Received our privately broadcast transaction (txid=%s) from the "
4500 "network from %s; stopping private broadcast attempts",
4501 txid.ToString(), pfrom.LogPeer());
4502 if (NUM_PRIVATE_BROADCAST_PER_TX > num_broadcasted.value()) {
4503 // Not all of the initial NUM_PRIVATE_BROADCAST_PER_TX connections were needed.
4504 // Tell CConnman it does not need to start the remaining ones.
4505 m_connman.m_private_broadcast.NumToOpenSub(NUM_PRIVATE_BROADCAST_PER_TX - num_broadcasted.value());
4506 }
4507 }
4508 4509 LOCK2(cs_main, m_tx_download_mutex);
4510 4511 const auto& [should_validate, package_to_validate] = m_txdownloadman.ReceivedTx(pfrom.GetId(), ptx);
4512 if (!should_validate) {
4513 if (pfrom.HasPermission(NetPermissionFlags::ForceRelay)) {
4514 // Always relay transactions received from peers with forcerelay
4515 // permission, even if they were already in the mempool, allowing
4516 // the node to function as a gateway for nodes hidden behind it.
4517 if (!m_mempool.exists(txid)) {
4518 LogInfo("Not relaying non-mempool transaction %s (wtxid=%s) from forcerelay peer=%d\n",
4519 txid.ToString(), wtxid.ToString(), pfrom.GetId());
4520 } else {
4521 LogInfo("Force relaying tx %s (wtxid=%s) from peer=%d\n",
4522 txid.ToString(), wtxid.ToString(), pfrom.GetId());
4523 InitiateTxBroadcastToAll(txid, wtxid);
4524 }
4525 }
4526 4527 if (package_to_validate) {
4528 const auto package_result{ProcessNewPackage(m_chainman.ActiveChainstate(), m_mempool, package_to_validate->m_txns, /*test_accept=*/false, /*client_maxfeerate=*/std::nullopt)};
4529 LogDebug(BCLog::TXPACKAGES, "package evaluation for %s: %s\n", package_to_validate->ToString(),
4530 package_result.m_state.IsValid() ? "package accepted" : "package rejected");
4531 ProcessPackageResult(package_to_validate.value(), package_result);
4532 }
4533 return;
4534 }
4535 4536 // ReceivedTx should not be telling us to validate the tx and a package.
4537 Assume(!package_to_validate.has_value());
4538 4539 const MempoolAcceptResult result = m_chainman.ProcessTransaction(ptx);
4540 const TxValidationState& state = result.m_state;
4541 4542 if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
4543 ProcessValidTx(pfrom.GetId(), ptx, result.m_replaced_transactions);
4544 pfrom.m_last_tx_time = GetTime<std::chrono::seconds>();
4545 }
4546 if (state.IsInvalid()) {
4547 if (auto package_to_validate{ProcessInvalidTx(pfrom.GetId(), ptx, state, /*first_time_failure=*/true)}) {
4548 const auto package_result{ProcessNewPackage(m_chainman.ActiveChainstate(), m_mempool, package_to_validate->m_txns, /*test_accept=*/false, /*client_maxfeerate=*/std::nullopt)};
4549 LogDebug(BCLog::TXPACKAGES, "package evaluation for %s: %s\n", package_to_validate->ToString(),
4550 package_result.m_state.IsValid() ? "package accepted" : "package rejected");
4551 ProcessPackageResult(package_to_validate.value(), package_result);
4552 }
4553 }
4554 4555 return;
4556 }
4557 4558 if (msg_type == NetMsgType::CMPCTBLOCK)
4559 {
4560 // Ignore cmpctblock received while importing
4561 if (m_chainman.m_blockman.LoadingBlocks()) {
4562 LogDebug(BCLog::CMPCTBLOCK, "%s sent us a compact block even though we are still loading blocks!", pfrom.LogPeer());
4563 return;
4564 } else if (m_opts.ignore_incoming_txs) {
4565 LogDebug(BCLog::CMPCTBLOCK, "%s sent us a compact block even though we are blocksonly!", pfrom.LogPeer());
4566 return;
4567 }
4568 4569 {
4570 LOCK(cs_main);
4571 const CNodeState *nodestate = State(pfrom.GetId());
4572 if (!nodestate->m_provides_cmpctblocks) {
4573 LogDebug(BCLog::CMPCTBLOCK, "%s sent us a compact block despite never having sent us a SENDCMPCT!", pfrom.LogPeer());
4574 return;
4575 }
4576 }
4577 4578 CBlockHeaderAndShortTxIDs cmpctblock;
4579 vRecv >> cmpctblock;
4580 4581 bool received_new_header = false;
4582 const auto blockhash = cmpctblock.header.GetHash();
4583 4584 {
4585 LOCK(cs_main);
4586 4587 const CBlockIndex* prev_block = m_chainman.m_blockman.LookupBlockIndex(cmpctblock.header.hashPrevBlock);
4588 if (!prev_block) {
4589 // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers
4590 if (!m_chainman.IsInitialBlockDownload()) {
4591 MaybeSendGetHeaders(pfrom, GetLocator(m_chainman.m_best_header), peer);
4592 }
4593 return;
4594 } else if (prev_block->nChainWork + GetBlockProof(cmpctblock.header) < GetAntiDoSWorkThreshold()) {
4595 // If we get a low-work header in a compact block, we can ignore it.
4596 LogDebug(BCLog::NET, "Ignoring low-work compact block from peer %d\n", pfrom.GetId());
4597 return;
4598 }
4599 4600 if (!m_chainman.m_blockman.LookupBlockIndex(blockhash)) {
4601 received_new_header = true;
4602 }
4603 }
4604 4605 const CBlockIndex *pindex = nullptr;
4606 BlockValidationState state;
4607 if (!m_chainman.ProcessNewBlockHeaders({{cmpctblock.header}}, /*min_pow_checked=*/true, state, &pindex)) {
4608 if (state.IsInvalid()) {
4609 MaybePunishNodeForBlock(pfrom.GetId(), state, /*via_compact_block=*/true, "invalid header via cmpctblock");
4610 return;
4611 }
4612 }
4613 4614 // If AcceptBlockHeader returned true, it set pindex
4615 Assert(pindex);
4616 if (received_new_header) {
4617 LogBlockHeader(*pindex, pfrom, /*via_compact_block=*/true);
4618 }
4619 4620 bool fProcessBLOCKTXN = false;
4621 4622 // If we end up treating this as a plain headers message, call that as well
4623 // without cs_main.
4624 bool fRevertToHeaderProcessing = false;
4625 4626 // Keep a CBlock for "optimistic" compactblock reconstructions (see
4627 // below)
4628 std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
4629 bool fBlockReconstructed = false;
4630 4631 {
4632 LOCK(cs_main);
4633 UpdateBlockAvailability(pfrom.GetId(), pindex->GetBlockHash());
4634 4635 CNodeState *nodestate = State(pfrom.GetId());
4636 4637 // If this was a new header with more work than our tip, update the
4638 // peer's last block announcement time
4639 if (received_new_header && pindex->nChainWork > m_chainman.ActiveChain().Tip()->nChainWork) {
4640 nodestate->m_last_block_announcement = GetTime();
4641 }
4642 4643 if (pindex->nStatus & BLOCK_HAVE_DATA) // Nothing to do here
4644 return;
4645 4646 auto range_flight = mapBlocksInFlight.equal_range(pindex->GetBlockHash());
4647 size_t already_in_flight = std::distance(range_flight.first, range_flight.second);
4648 bool requested_block_from_this_peer{false};
4649 4650 // Multimap ensures ordering of outstanding requests. It's either empty or first in line.
4651 bool first_in_flight = already_in_flight == 0 || (range_flight.first->second.first == pfrom.GetId());
4652 4653 while (range_flight.first != range_flight.second) {
4654 if (range_flight.first->second.first == pfrom.GetId()) {
4655 requested_block_from_this_peer = true;
4656 break;
4657 }
4658 range_flight.first++;
4659 }
4660 4661 if (!requested_block_from_this_peer && !pfrom.m_bip152_highbandwidth_to) {
4662 LogDebug(BCLog::CMPCTBLOCK, "%s, not marked as high-bandwidth, sent us an unsolicited compact block!", pfrom.LogPeer());
4663 return;
4664 }
4665 4666 if (pindex->nChainWork <= m_chainman.ActiveChain().Tip()->nChainWork || // We know something better
4667 pindex->nTx != 0) { // We had this block at some point, but pruned it
4668 if (requested_block_from_this_peer) {
4669 // We requested this block for some reason, but our mempool will probably be useless
4670 // so we just grab the block via normal getdata
4671 std::vector<CInv> vInv(1);
4672 vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(peer), blockhash);
4673 MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv);
4674 }
4675 return;
4676 }
4677 4678 // If we're not close to tip yet, give up and let parallel block fetch work its magic
4679 if (!already_in_flight && !CanDirectFetch()) {
4680 return;
4681 }
4682 4683 // We want to be a bit conservative just to be extra careful about DoS
4684 // possibilities in compact block processing...
4685 if (pindex->nHeight <= m_chainman.ActiveChain().Height() + 2) {
4686 if ((already_in_flight < MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK && nodestate->vBlocksInFlight.size() < MAX_BLOCKS_IN_TRANSIT_PER_PEER) ||
4687 requested_block_from_this_peer) {
4688 std::list<QueuedBlock>::iterator* queuedBlockIt = nullptr;
4689 if (!BlockRequested(pfrom.GetId(), *pindex, &queuedBlockIt)) {
4690 if (!(*queuedBlockIt)->partialBlock)
4691 (*queuedBlockIt)->partialBlock.reset(new PartiallyDownloadedBlock(&m_mempool));
4692 else {
4693 // The block was already in flight using compact blocks from the same peer
4694 LogDebug(BCLog::NET, "Peer sent us compact block we were already syncing!\n");
4695 return;
4696 }
4697 }
4698 4699 PartiallyDownloadedBlock& partialBlock = *(*queuedBlockIt)->partialBlock;
4700 ReadStatus status = partialBlock.InitData(cmpctblock, vExtraTxnForCompact);
4701 if (status == READ_STATUS_INVALID) {
4702 RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect
4703 Misbehaving(peer, "invalid compact block");
4704 return;
4705 } else if (status == READ_STATUS_FAILED) {
4706 if (first_in_flight) {
4707 // Duplicate txindexes, the block is now in-flight, so just request it
4708 std::vector<CInv> vInv(1);
4709 vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(peer), blockhash);
4710 MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv);
4711 } else {
4712 // Give up for this peer and wait for other peer(s)
4713 RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId());
4714 }
4715 return;
4716 }
4717 4718 BlockTransactionsRequest req;
4719 for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
4720 if (!partialBlock.IsTxAvailable(i))
4721 req.indexes.push_back(i);
4722 }
4723 if (req.indexes.empty()) {
4724 fProcessBLOCKTXN = true;
4725 } else if (first_in_flight) {
4726 // We will try to round-trip any compact blocks we get on failure,
4727 // as long as it's first...
4728 req.blockhash = pindex->GetBlockHash();
4729 MakeAndPushMessage(pfrom, NetMsgType::GETBLOCKTXN, req);
4730 } else if (pfrom.m_bip152_highbandwidth_to &&
4731 (!pfrom.IsInboundConn() ||
4732 IsBlockRequestedFromOutbound(blockhash) ||
4733 already_in_flight < MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK - 1)) {
4734 // ... or it's a hb relay peer and:
4735 // - peer is outbound, or
4736 // - we already have an outbound attempt in flight(so we'll take what we can get), or
4737 // - it's not the final parallel download slot (which we may reserve for first outbound)
4738 req.blockhash = pindex->GetBlockHash();
4739 MakeAndPushMessage(pfrom, NetMsgType::GETBLOCKTXN, req);
4740 } else {
4741 // Give up for this peer and wait for other peer(s)
4742 RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId());
4743 }
4744 } else {
4745 // This block is either already in flight from a different
4746 // peer, or this peer has too many blocks outstanding to
4747 // download from.
4748 // Optimistically try to reconstruct anyway since we might be
4749 // able to without any round trips.
4750 PartiallyDownloadedBlock tempBlock(&m_mempool);
4751 ReadStatus status = tempBlock.InitData(cmpctblock, vExtraTxnForCompact);
4752 if (status != READ_STATUS_OK) {
4753 // TODO: don't ignore failures
4754 return;
4755 }
4756 std::vector<CTransactionRef> dummy;
4757 const CBlockIndex* prev_block{Assume(m_chainman.m_blockman.LookupBlockIndex(cmpctblock.header.hashPrevBlock))};
4758 status = tempBlock.FillBlock(*pblock, dummy,
4759 /*segwit_active=*/DeploymentActiveAfter(prev_block, m_chainman, Consensus::DEPLOYMENT_SEGWIT));
4760 if (status == READ_STATUS_OK) {
4761 fBlockReconstructed = true;
4762 }
4763 }
4764 } else {
4765 if (requested_block_from_this_peer) {
4766 // We requested this block, but its far into the future, so our
4767 // mempool will probably be useless - request the block normally
4768 std::vector<CInv> vInv(1);
4769 vInv[0] = CInv(MSG_BLOCK | GetFetchFlags(peer), blockhash);
4770 MakeAndPushMessage(pfrom, NetMsgType::GETDATA, vInv);
4771 return;
4772 } else {
4773 // If this was an announce-cmpctblock, we want the same treatment as a header message
4774 fRevertToHeaderProcessing = true;
4775 }
4776 }
4777 } // cs_main
4778 4779 if (fProcessBLOCKTXN) {
4780 BlockTransactions txn;
4781 txn.blockhash = blockhash;
4782 return ProcessCompactBlockTxns(pfrom, peer, txn);
4783 }
4784 4785 if (fRevertToHeaderProcessing) {
4786 // Headers received from HB compact block peers are permitted to be
4787 // relayed before full validation (see BIP 152), so we don't want to disconnect
4788 // the peer if the header turns out to be for an invalid block.
4789 // Note that if a peer tries to build on an invalid chain, that
4790 // will be detected and the peer will be disconnected/discouraged.
4791 return ProcessHeadersMessage(pfrom, peer, {cmpctblock.header}, /*via_compact_block=*/true);
4792 }
4793 4794 if (fBlockReconstructed) {
4795 // If we got here, we were able to optimistically reconstruct a
4796 // block that is in flight from some other peer.
4797 {
4798 LOCK(cs_main);
4799 mapBlockSource.emplace(pblock->GetHash(), std::make_pair(pfrom.GetId(), false));
4800 }
4801 // Setting force_processing to true means that we bypass some of
4802 // our anti-DoS protections in AcceptBlock, which filters
4803 // unrequested blocks that might be trying to waste our resources
4804 // (eg disk space). Because we only try to reconstruct blocks when
4805 // we're close to caught up (via the CanDirectFetch() requirement
4806 // above, combined with the behavior of not requesting blocks until
4807 // we have a chain with at least the minimum chain work), and we ignore
4808 // compact blocks with less work than our tip, it is safe to treat
4809 // reconstructed compact blocks as having been requested.
4810 ProcessBlock(pfrom, pblock, /*force_processing=*/true, /*min_pow_checked=*/true);
4811 LOCK(cs_main); // hold cs_main for CBlockIndex::IsValid()
4812 if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS)) {
4813 // Clear download state for this block, which is in
4814 // process from some other peer. We do this after calling
4815 // ProcessNewBlock so that a malleated cmpctblock announcement
4816 // can't be used to interfere with block relay.
4817 RemoveBlockRequest(pblock->GetHash(), std::nullopt);
4818 }
4819 }
4820 return;
4821 }
4822 4823 if (msg_type == NetMsgType::BLOCKTXN)
4824 {
4825 // Ignore blocktxn received while importing
4826 if (m_chainman.m_blockman.LoadingBlocks()) {
4827 LogDebug(BCLog::NET, "Unexpected blocktxn message received from peer %d\n", pfrom.GetId());
4828 return;
4829 }
4830 4831 BlockTransactions resp;
4832 vRecv >> resp;
4833 4834 return ProcessCompactBlockTxns(pfrom, peer, resp);
4835 }
4836 4837 if (msg_type == NetMsgType::HEADERS)
4838 {
4839 // Ignore headers received while importing
4840 if (m_chainman.m_blockman.LoadingBlocks()) {
4841 LogDebug(BCLog::NET, "Unexpected headers message received from peer %d\n", pfrom.GetId());
4842 return;
4843 }
4844 4845 std::vector<CBlockHeader> headers;
4846 4847 // Bypass the normal CBlock deserialization, as we don't want to risk deserializing 2000 full blocks.
4848 unsigned int nCount = ReadCompactSize(vRecv);
4849 if (nCount > m_opts.max_headers_result) {
4850 Misbehaving(peer, strprintf("headers message size = %u", nCount));
4851 return;
4852 }
4853 headers.resize(nCount);
4854 for (unsigned int n = 0; n < nCount; n++) {
4855 vRecv >> headers[n];
4856 ReadCompactSize(vRecv); // ignore tx count; assume it is 0.
4857 }
4858 4859 ProcessHeadersMessage(pfrom, peer, std::move(headers), /*via_compact_block=*/false);
4860 4861 // Check if the headers presync progress needs to be reported to validation.
4862 // This needs to be done without holding the m_headers_presync_mutex lock.
4863 if (m_headers_presync_should_signal.exchange(false)) {
4864 HeadersPresyncStats stats;
4865 {
4866 LOCK(m_headers_presync_mutex);
4867 auto it = m_headers_presync_stats.find(m_headers_presync_bestpeer);
4868 if (it != m_headers_presync_stats.end()) stats = it->second;
4869 }
4870 if (stats.second) {
4871 m_chainman.ReportHeadersPresync(stats.second->first, stats.second->second);
4872 }
4873 }
4874 4875 return;
4876 }
4877 4878 if (msg_type == NetMsgType::BLOCK)
4879 {
4880 // Ignore block received while importing
4881 if (m_chainman.m_blockman.LoadingBlocks()) {
4882 LogDebug(BCLog::NET, "Unexpected block message received from peer %d\n", pfrom.GetId());
4883 return;
4884 }
4885 4886 std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
4887 vRecv >> TX_WITH_WITNESS(*pblock);
4888 4889 LogDebug(BCLog::NET, "received block %s peer=%d\n", pblock->GetHash().ToString(), pfrom.GetId());
4890 4891 const CBlockIndex* prev_block{WITH_LOCK(m_chainman.GetMutex(), return m_chainman.m_blockman.LookupBlockIndex(pblock->hashPrevBlock))};
4892 4893 // Check for possible mutation if it connects to something we know so we can check for DEPLOYMENT_SEGWIT being active
4894 if (prev_block && IsBlockMutated(/*block=*/*pblock,
4895 /*check_witness_root=*/DeploymentActiveAfter(prev_block, m_chainman, Consensus::DEPLOYMENT_SEGWIT))) {
4896 LogDebug(BCLog::NET, "Received mutated block from peer=%d\n", peer.m_id);
4897 Misbehaving(peer, "mutated block");
4898 WITH_LOCK(cs_main, RemoveBlockRequest(pblock->GetHash(), peer.m_id));
4899 return;
4900 }
4901 4902 bool forceProcessing = false;
4903 const uint256 hash(pblock->GetHash());
4904 bool min_pow_checked = false;
4905 {
4906 LOCK(cs_main);
4907 // Always process the block if we requested it, since we may
4908 // need it even when it's not a candidate for a new best tip.
4909 forceProcessing = IsBlockRequested(hash);
4910 RemoveBlockRequest(hash, pfrom.GetId());
4911 // mapBlockSource is only used for punishing peers and setting
4912 // which peers send us compact blocks, so the race between here and
4913 // cs_main in ProcessNewBlock is fine.
4914 mapBlockSource.emplace(hash, std::make_pair(pfrom.GetId(), true));
4915 4916 // Check claimed work on this block against our anti-dos thresholds.
4917 if (prev_block && prev_block->nChainWork + GetBlockProof(*pblock) >= GetAntiDoSWorkThreshold()) {
4918 min_pow_checked = true;
4919 }
4920 }
4921 ProcessBlock(pfrom, pblock, forceProcessing, min_pow_checked);
4922 return;
4923 }
4924 4925 if (msg_type == NetMsgType::GETADDR) {
4926 // This asymmetric behavior for inbound and outbound connections was introduced
4927 // to prevent a fingerprinting attack: an attacker can send specific fake addresses
4928 // to users' AddrMan and later request them by sending getaddr messages.
4929 // Making nodes which are behind NAT and can only make outgoing connections ignore
4930 // the getaddr message mitigates the attack.
4931 if (!pfrom.IsInboundConn()) {
4932 LogDebug(BCLog::NET, "Ignoring \"getaddr\" from %s connection. peer=%d\n", pfrom.ConnectionTypeAsString(), pfrom.GetId());
4933 return;
4934 }
4935 4936 // Since this must be an inbound connection, SetupAddressRelay will
4937 // never fail.
4938 Assume(SetupAddressRelay(pfrom, peer));
4939 4940 // Only send one GetAddr response per connection to reduce resource waste
4941 // and discourage addr stamping of INV announcements.
4942 if (peer.m_getaddr_recvd) {
4943 LogDebug(BCLog::NET, "Ignoring repeated \"getaddr\". peer=%d\n", pfrom.GetId());
4944 return;
4945 }
4946 peer.m_getaddr_recvd = true;
4947 4948 peer.m_addrs_to_send.clear();
4949 std::vector<CAddress> vAddr;
4950 if (pfrom.HasPermission(NetPermissionFlags::Addr)) {
4951 vAddr = m_connman.GetAddressesUnsafe(MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND, /*network=*/std::nullopt);
4952 } else {
4953 vAddr = m_connman.GetAddresses(pfrom, MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND);
4954 }
4955 for (const CAddress &addr : vAddr) {
4956 PushAddress(peer, addr);
4957 }
4958 return;
4959 }
4960 4961 if (msg_type == NetMsgType::MEMPOOL) {
4962 // Only process received mempool messages if we advertise NODE_BLOOM
4963 // or if the peer has mempool permissions.
4964 if (!(peer.m_our_services & NODE_BLOOM) && !pfrom.HasPermission(NetPermissionFlags::Mempool))
4965 {
4966 if (!pfrom.HasPermission(NetPermissionFlags::NoBan))
4967 {
4968 LogDebug(BCLog::NET, "mempool request with bloom filters disabled, %s", pfrom.DisconnectMsg());
4969 pfrom.fDisconnect = true;
4970 }
4971 return;
4972 }
4973 4974 if (m_connman.OutboundTargetReached(false) && !pfrom.HasPermission(NetPermissionFlags::Mempool))
4975 {
4976 if (!pfrom.HasPermission(NetPermissionFlags::NoBan))
4977 {
4978 LogDebug(BCLog::NET, "mempool request with bandwidth limit reached, %s", pfrom.DisconnectMsg());
4979 pfrom.fDisconnect = true;
4980 }
4981 return;
4982 }
4983 4984 if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
4985 LOCK(tx_relay->m_tx_inventory_mutex);
4986 tx_relay->m_send_mempool = true;
4987 }
4988 return;
4989 }
4990 4991 if (msg_type == NetMsgType::PING) {
4992 if (pfrom.GetCommonVersion() > BIP0031_VERSION) {
4993 uint64_t nonce = 0;
4994 vRecv >> nonce;
4995 // Echo the message back with the nonce. This allows for two useful features:
4996 //
4997 // 1) A remote node can quickly check if the connection is operational
4998 // 2) Remote nodes can measure the latency of the network thread. If this node
4999 // is overloaded it won't respond to pings quickly and the remote node can
5000 // avoid sending us more work, like chain download requests.
5001 //
5002 // The nonce stops the remote getting confused between different pings: without
5003 // it, if the remote node sends a ping once per second and this node takes 5
5004 // seconds to respond to each, the 5th ping the remote sends would appear to
5005 // return very quickly.
5006 MakeAndPushMessage(pfrom, NetMsgType::PONG, nonce);
5007 }
5008 return;
5009 }
5010 5011 if (msg_type == NetMsgType::PONG) {
5012 ProcessPong(pfrom, peer, /*ping_end=*/time_received, vRecv);
5013 return;
5014 }
5015 5016 if (msg_type == NetMsgType::FILTERLOAD) {
5017 if (!(peer.m_our_services & NODE_BLOOM)) {
5018 LogDebug(BCLog::NET, "filterload received despite not offering bloom services, %s", pfrom.DisconnectMsg());
5019 pfrom.fDisconnect = true;
5020 return;
5021 }
5022 CBloomFilter filter;
5023 vRecv >> filter;
5024 5025 if (!filter.IsWithinSizeConstraints())
5026 {
5027 // There is no excuse for sending a too-large filter
5028 Misbehaving(peer, "too-large bloom filter");
5029 } else if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
5030 {
5031 LOCK(tx_relay->m_bloom_filter_mutex);
5032 tx_relay->m_bloom_filter.reset(new CBloomFilter(filter));
5033 tx_relay->m_relay_txs = true;
5034 }
5035 pfrom.m_bloom_filter_loaded = true;
5036 pfrom.m_relays_txs = true;
5037 }
5038 return;
5039 }
5040 5041 if (msg_type == NetMsgType::FILTERADD) {
5042 if (!(peer.m_our_services & NODE_BLOOM)) {
5043 LogDebug(BCLog::NET, "filteradd received despite not offering bloom services, %s", pfrom.DisconnectMsg());
5044 pfrom.fDisconnect = true;
5045 return;
5046 }
5047 std::vector<unsigned char> vData;
5048 vRecv >> vData;
5049 5050 // Nodes must NEVER send a data item > MAX_SCRIPT_ELEMENT_SIZE bytes (the max size for a script data object,
5051 // and thus, the maximum size any matched object can have) in a filteradd message
5052 bool bad = false;
5053 if (vData.size() > MAX_SCRIPT_ELEMENT_SIZE) {
5054 bad = true;
5055 } else if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
5056 LOCK(tx_relay->m_bloom_filter_mutex);
5057 if (tx_relay->m_bloom_filter) {
5058 tx_relay->m_bloom_filter->insert(vData);
5059 } else {
5060 bad = true;
5061 }
5062 }
5063 if (bad) {
5064 Misbehaving(peer, "bad filteradd message");
5065 }
5066 return;
5067 }
5068 5069 if (msg_type == NetMsgType::FILTERCLEAR) {
5070 if (!(peer.m_our_services & NODE_BLOOM)) {
5071 LogDebug(BCLog::NET, "filterclear received despite not offering bloom services, %s", pfrom.DisconnectMsg());
5072 pfrom.fDisconnect = true;
5073 return;
5074 }
5075 auto tx_relay = peer.GetTxRelay();
5076 if (!tx_relay) return;
5077 5078 {
5079 LOCK(tx_relay->m_bloom_filter_mutex);
5080 tx_relay->m_bloom_filter = nullptr;
5081 tx_relay->m_relay_txs = true;
5082 }
5083 pfrom.m_bloom_filter_loaded = false;
5084 pfrom.m_relays_txs = true;
5085 return;
5086 }
5087 5088 if (msg_type == NetMsgType::FEEFILTER) {
5089 CAmount newFeeFilter = 0;
5090 vRecv >> newFeeFilter;
5091 if (MoneyRange(newFeeFilter)) {
5092 if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
5093 tx_relay->m_fee_filter_received = newFeeFilter;
5094 }
5095 LogDebug(BCLog::NET, "received: feefilter of %s from peer=%d\n", CFeeRate(newFeeFilter).ToString(), pfrom.GetId());
5096 }
5097 return;
5098 }
5099 5100 if (msg_type == NetMsgType::GETCFILTERS) {
5101 ProcessGetCFilters(pfrom, peer, vRecv);
5102 return;
5103 }
5104 5105 if (msg_type == NetMsgType::GETCFHEADERS) {
5106 ProcessGetCFHeaders(pfrom, peer, vRecv);
5107 return;
5108 }
5109 5110 if (msg_type == NetMsgType::GETCFCHECKPT) {
5111 ProcessGetCFCheckPt(pfrom, peer, vRecv);
5112 return;
5113 }
5114 5115 if (msg_type == NetMsgType::NOTFOUND) {
5116 std::vector<CInv> vInv;
5117 vRecv >> vInv;
5118 std::vector<GenTxid> tx_invs;
5119 if (vInv.size() <= node::MAX_PEER_TX_ANNOUNCEMENTS + MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
5120 for (CInv &inv : vInv) {
5121 if (inv.IsGenTxMsg()) {
5122 tx_invs.emplace_back(ToGenTxid(inv));
5123 }
5124 }
5125 }
5126 LOCK(m_tx_download_mutex);
5127 m_txdownloadman.ReceivedNotFound(pfrom.GetId(), tx_invs);
5128 return;
5129 }
5130 5131 // Ignore unknown message types for extensibility
5132 LogDebug(BCLog::NET, "Unknown message type \"%s\" from peer=%d", SanitizeString(msg_type), pfrom.GetId());
5133 return;
5134 }
5135 5136 bool PeerManagerImpl::MaybeDiscourageAndDisconnect(CNode& pnode, Peer& peer)
5137 {
5138 {
5139 LOCK(peer.m_misbehavior_mutex);
5140 5141 // There's nothing to do if the m_should_discourage flag isn't set
5142 if (!peer.m_should_discourage) return false;
5143 5144 peer.m_should_discourage = false;
5145 } // peer.m_misbehavior_mutex
5146 5147 if (pnode.HasPermission(NetPermissionFlags::NoBan)) {
5148 // We never disconnect or discourage peers for bad behavior if they have NetPermissionFlags::NoBan permission
5149 LogWarning("Not punishing noban peer %d!", peer.m_id);
5150 return false;
5151 }
5152 5153 if (pnode.IsManualConn()) {
5154 // We never disconnect or discourage manual peers for bad behavior
5155 LogWarning("Not punishing manually connected peer %d!", peer.m_id);
5156 return false;
5157 }
5158 5159 if (pnode.addr.IsLocal()) {
5160 // We disconnect local peers for bad behavior but don't discourage (since that would discourage
5161 // all peers on the same local address)
5162 LogDebug(BCLog::NET, "Warning: disconnecting but not discouraging %s peer %d!\n",
5163 pnode.m_inbound_onion ? "inbound onion" : "local", peer.m_id);
5164 pnode.fDisconnect = true;
5165 return true;
5166 }
5167 5168 // Normal case: Disconnect the peer and discourage all nodes sharing the address
5169 LogDebug(BCLog::NET, "Disconnecting and discouraging peer %d!\n", peer.m_id);
5170 if (m_banman) m_banman->Discourage(pnode.addr);
5171 m_connman.DisconnectNode(pnode.addr);
5172 return true;
5173 }
5174 5175 bool PeerManagerImpl::ProcessMessages(CNode& node, std::atomic<bool>& interruptMsgProc)
5176 {
5177 AssertLockNotHeld(m_tx_download_mutex);
5178 AssertLockHeld(g_msgproc_mutex);
5179 5180 PeerRef maybe_peer{GetPeerRef(node.GetId())};
5181 if (maybe_peer == nullptr) return false;
5182 Peer& peer{*maybe_peer};
5183 5184 // For outbound connections, ensure that the initial VERSION message
5185 // has been sent first before processing any incoming messages
5186 if (!node.IsInboundConn() && !peer.m_outbound_version_message_sent) return false;
5187 5188 {
5189 LOCK(peer.m_getdata_requests_mutex);
5190 if (!peer.m_getdata_requests.empty()) {
5191 ProcessGetData(node, peer, interruptMsgProc);
5192 }
5193 }
5194 5195 const bool processed_orphan = ProcessOrphanTx(peer);
5196 5197 if (node.fDisconnect)
5198 return false;
5199 5200 if (processed_orphan) return true;
5201 5202 // this maintains the order of responses
5203 // and prevents m_getdata_requests to grow unbounded
5204 {
5205 LOCK(peer.m_getdata_requests_mutex);
5206 if (!peer.m_getdata_requests.empty()) return true;
5207 }
5208 5209 // Don't bother if send buffer is too full to respond anyway
5210 if (node.fPauseSend) return false;
5211 5212 auto poll_result{node.PollMessage()};
5213 if (!poll_result) {
5214 // No message to process
5215 return false;
5216 }
5217 5218 CNetMessage& msg{poll_result->first};
5219 bool fMoreWork = poll_result->second;
5220 5221 TRACEPOINT(net, inbound_message,
5222 node.GetId(),
5223 node.m_addr_name.c_str(),
5224 node.ConnectionTypeAsString().c_str(),
5225 msg.m_type.c_str(),
5226 msg.m_recv.size(),
5227 msg.m_recv.data()
5228 );
5229 5230 if (m_opts.capture_messages) {
5231 CaptureMessage(node.addr, msg.m_type, MakeUCharSpan(msg.m_recv), /*is_incoming=*/true);
5232 }
5233 5234 try {
5235 ProcessMessage(peer, node, msg.m_type, msg.m_recv, msg.m_time, interruptMsgProc);
5236 if (interruptMsgProc) return false;
5237 {
5238 LOCK(peer.m_getdata_requests_mutex);
5239 if (!peer.m_getdata_requests.empty()) fMoreWork = true;
5240 }
5241 // Does this peer have an orphan ready to reconsider?
5242 // (Note: we may have provided a parent for an orphan provided
5243 // by another peer that was already processed; in that case,
5244 // the extra work may not be noticed, possibly resulting in an
5245 // unnecessary 100ms delay)
5246 LOCK(m_tx_download_mutex);
5247 if (m_txdownloadman.HaveMoreWork(peer.m_id)) fMoreWork = true;
5248 } catch (const std::exception& e) {
5249 LogDebug(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());
5250 } catch (...) {
5251 LogDebug(BCLog::NET, "%s(%s, %u bytes): Unknown exception caught\n", __func__, SanitizeString(msg.m_type), msg.m_message_size);
5252 }
5253 5254 return fMoreWork;
5255 }
5256 5257 void PeerManagerImpl::ConsiderEviction(CNode& pto, Peer& peer, std::chrono::seconds time_in_seconds)
5258 {
5259 AssertLockHeld(cs_main);
5260 5261 CNodeState &state = *State(pto.GetId());
5262 5263 if (!state.m_chain_sync.m_protect && pto.IsOutboundOrBlockRelayConn() && state.fSyncStarted) {
5264 // This is an outbound peer subject to disconnection if they don't
5265 // announce a block with as much work as the current tip within
5266 // CHAIN_SYNC_TIMEOUT + HEADERS_RESPONSE_TIME seconds (note: if
5267 // their chain has more work than ours, we should sync to it,
5268 // unless it's invalid, in which case we should find that out and
5269 // disconnect from them elsewhere).
5270 if (state.pindexBestKnownBlock != nullptr && state.pindexBestKnownBlock->nChainWork >= m_chainman.ActiveChain().Tip()->nChainWork) {
5271 // The outbound peer has sent us a block with at least as much work as our current tip, so reset the timeout if it was set
5272 if (state.m_chain_sync.m_timeout != 0s) {
5273 state.m_chain_sync.m_timeout = 0s;
5274 state.m_chain_sync.m_work_header = nullptr;
5275 state.m_chain_sync.m_sent_getheaders = false;
5276 }
5277 } 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)) {
5278 // At this point we know that the outbound peer has either never sent us a block/header or they have, but its tip is behind ours
5279 // AND
5280 // we are noticing this for the first time (m_timeout is 0)
5281 // OR we noticed this at some point within the last CHAIN_SYNC_TIMEOUT + HEADERS_RESPONSE_TIME seconds and set a timeout
5282 // for them, they caught up to our tip at the time of setting the timer but not to our current one (we've also advanced).
5283 // Either way, set a new timeout based on our current tip.
5284 state.m_chain_sync.m_timeout = time_in_seconds + CHAIN_SYNC_TIMEOUT;
5285 state.m_chain_sync.m_work_header = m_chainman.ActiveChain().Tip();
5286 state.m_chain_sync.m_sent_getheaders = false;
5287 } else if (state.m_chain_sync.m_timeout > 0s && time_in_seconds > state.m_chain_sync.m_timeout) {
5288 // No evidence yet that our peer has synced to a chain with work equal to that
5289 // of our tip, when we first detected it was behind. Send a single getheaders
5290 // message to give the peer a chance to update us.
5291 if (state.m_chain_sync.m_sent_getheaders) {
5292 // They've run out of time to catch up!
5293 LogInfo("Outbound peer has old chain, best known block = %s, %s", state.pindexBestKnownBlock != nullptr ? state.pindexBestKnownBlock->GetBlockHash().ToString() : "<none>", pto.DisconnectMsg());
5294 pto.fDisconnect = true;
5295 } else {
5296 assert(state.m_chain_sync.m_work_header);
5297 // Here, we assume that the getheaders message goes out,
5298 // because it'll either go out or be skipped because of a
5299 // getheaders in-flight already, in which case the peer should
5300 // still respond to us with a sufficiently high work chain tip.
5301 MaybeSendGetHeaders(pto,
5302 GetLocator(state.m_chain_sync.m_work_header->pprev),
5303 peer);
5304 LogDebug(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() : "<none>", state.m_chain_sync.m_work_header->GetBlockHash().ToString());
5305 state.m_chain_sync.m_sent_getheaders = true;
5306 // Bump the timeout to allow a response, which could clear the timeout
5307 // (if the response shows the peer has synced), reset the timeout (if
5308 // the peer syncs to the required work but not to our tip), or result
5309 // in disconnect (if we advance to the timeout and pindexBestKnownBlock
5310 // has not sufficiently progressed)
5311 state.m_chain_sync.m_timeout = time_in_seconds + HEADERS_RESPONSE_TIME;
5312 }
5313 }
5314 }
5315 }
5316 5317 void PeerManagerImpl::EvictExtraOutboundPeers(NodeClock::time_point now)
5318 {
5319 // If we have any extra block-relay-only peers, disconnect the youngest unless
5320 // it's given us a block -- in which case, compare with the second-youngest, and
5321 // out of those two, disconnect the peer who least recently gave us a block.
5322 // The youngest block-relay-only peer would be the extra peer we connected
5323 // to temporarily in order to sync our tip; see net.cpp.
5324 // Note that we use higher nodeid as a measure for most recent connection.
5325 if (m_connman.GetExtraBlockRelayCount() > 0) {
5326 std::pair<NodeId, std::chrono::seconds> youngest_peer{-1, 0}, next_youngest_peer{-1, 0};
5327 5328 m_connman.ForEachNode([&](CNode* pnode) {
5329 if (!pnode->IsBlockOnlyConn() || pnode->fDisconnect) return;
5330 if (pnode->GetId() > youngest_peer.first) {
5331 next_youngest_peer = youngest_peer;
5332 youngest_peer.first = pnode->GetId();
5333 youngest_peer.second = pnode->m_last_block_time;
5334 }
5335 });
5336 NodeId to_disconnect = youngest_peer.first;
5337 if (youngest_peer.second > next_youngest_peer.second) {
5338 // Our newest block-relay-only peer gave us a block more recently;
5339 // disconnect our second youngest.
5340 to_disconnect = next_youngest_peer.first;
5341 }
5342 m_connman.ForNode(to_disconnect, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
5343 AssertLockHeld(::cs_main);
5344 // Make sure we're not getting a block right now, and that
5345 // we've been connected long enough for this eviction to happen
5346 // at all.
5347 // Note that we only request blocks from a peer if we learn of a
5348 // valid headers chain with at least as much work as our tip.
5349 CNodeState *node_state = State(pnode->GetId());
5350 if (node_state == nullptr ||
5351 (now - pnode->m_connected >= MINIMUM_CONNECT_TIME && node_state->vBlocksInFlight.empty())) {
5352 pnode->fDisconnect = true;
5353 LogDebug(BCLog::NET, "disconnecting extra block-relay-only peer=%d (last block received at time %d)\n",
5354 pnode->GetId(), count_seconds(pnode->m_last_block_time));
5355 return true;
5356 } else {
5357 LogDebug(BCLog::NET, "keeping block-relay-only peer=%d chosen for eviction (connect time: %d, blocks_in_flight: %d)\n",
5358 pnode->GetId(), TicksSinceEpoch<std::chrono::seconds>(pnode->m_connected), node_state->vBlocksInFlight.size());
5359 }
5360 return false;
5361 });
5362 }
5363 5364 // Check whether we have too many outbound-full-relay peers
5365 if (m_connman.GetExtraFullOutboundCount() > 0) {
5366 // If we have more outbound-full-relay peers than we target, disconnect one.
5367 // Pick the outbound-full-relay peer that least recently announced
5368 // us a new block, with ties broken by choosing the more recent
5369 // connection (higher node id)
5370 // Protect peers from eviction if we don't have another connection
5371 // to their network, counting both outbound-full-relay and manual peers.
5372 NodeId worst_peer = -1;
5373 int64_t oldest_block_announcement = std::numeric_limits<int64_t>::max();
5374 5375 m_connman.ForEachNode([&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main, m_connman.GetNodesMutex()) {
5376 AssertLockHeld(::cs_main);
5377 5378 // Only consider outbound-full-relay peers that are not already
5379 // marked for disconnection
5380 if (!pnode->IsFullOutboundConn() || pnode->fDisconnect) return;
5381 CNodeState *state = State(pnode->GetId());
5382 if (state == nullptr) return; // shouldn't be possible, but just in case
5383 // Don't evict our protected peers
5384 if (state->m_chain_sync.m_protect) return;
5385 // If this is the only connection on a particular network that is
5386 // OUTBOUND_FULL_RELAY or MANUAL, protect it.
5387 if (!m_connman.MultipleManualOrFullOutboundConns(pnode->addr.GetNetwork())) return;
5388 if (state->m_last_block_announcement < oldest_block_announcement || (state->m_last_block_announcement == oldest_block_announcement && pnode->GetId() > worst_peer)) {
5389 worst_peer = pnode->GetId();
5390 oldest_block_announcement = state->m_last_block_announcement;
5391 }
5392 });
5393 if (worst_peer != -1) {
5394 bool disconnected = m_connman.ForNode(worst_peer, [&](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
5395 AssertLockHeld(::cs_main);
5396 5397 // Only disconnect a peer that has been connected to us for
5398 // some reasonable fraction of our check-frequency, to give
5399 // it time for new information to have arrived.
5400 // Also don't disconnect any peer we're trying to download a
5401 // block from.
5402 CNodeState &state = *State(pnode->GetId());
5403 if (now - pnode->m_connected > MINIMUM_CONNECT_TIME && state.vBlocksInFlight.empty()) {
5404 LogDebug(BCLog::NET, "disconnecting extra outbound peer=%d (last block announcement received at time %d)\n", pnode->GetId(), oldest_block_announcement);
5405 pnode->fDisconnect = true;
5406 return true;
5407 } else {
5408 LogDebug(BCLog::NET, "keeping outbound peer=%d chosen for eviction (connect time: %d, blocks_in_flight: %d)\n",
5409 pnode->GetId(), TicksSinceEpoch<std::chrono::seconds>(pnode->m_connected), state.vBlocksInFlight.size());
5410 return false;
5411 }
5412 });
5413 if (disconnected) {
5414 // If we disconnected an extra peer, that means we successfully
5415 // connected to at least one peer after the last time we
5416 // detected a stale tip. Don't try any more extra peers until
5417 // we next detect a stale tip, to limit the load we put on the
5418 // network from these extra connections.
5419 m_connman.SetTryNewOutboundPeer(false);
5420 }
5421 }
5422 }
5423 }
5424 5425 void PeerManagerImpl::CheckForStaleTipAndEvictPeers()
5426 {
5427 LOCK(cs_main);
5428 5429 const auto current_time{NodeClock::now()};
5430 auto now{GetTime<std::chrono::seconds>()};
5431 5432 EvictExtraOutboundPeers(current_time);
5433 5434 if (now > m_stale_tip_check_time) {
5435 // Check whether our tip is stale, and if so, allow using an extra
5436 // outbound peer
5437 if (!m_chainman.m_blockman.LoadingBlocks() && m_connman.GetNetworkActive() && m_connman.GetUseAddrmanOutgoing() && TipMayBeStale()) {
5438 LogInfo("Potential stale tip detected, will try using extra outbound peer (last tip update: %d seconds ago)\n",
5439 count_seconds(now - m_last_tip_update.load()));
5440 m_connman.SetTryNewOutboundPeer(true);
5441 } else if (m_connman.GetTryNewOutboundPeer()) {
5442 m_connman.SetTryNewOutboundPeer(false);
5443 }
5444 m_stale_tip_check_time = now + STALE_CHECK_INTERVAL;
5445 }
5446 5447 if (!m_initial_sync_finished && CanDirectFetch()) {
5448 m_connman.StartExtraBlockRelayPeers();
5449 m_initial_sync_finished = true;
5450 }
5451 }
5452 5453 void PeerManagerImpl::MaybeSendPing(CNode& node_to, Peer& peer, NodeClock::time_point now)
5454 {
5455 if (m_connman.ShouldRunInactivityChecks(node_to, now) &&
5456 peer.m_ping_nonce_sent &&
5457 now > peer.m_ping_start.load() + TIMEOUT_INTERVAL)
5458 {
5459 // The ping timeout is using mocktime. To disable the check during
5460 // testing, increase -peertimeout.
5461 LogDebug(BCLog::NET, "ping timeout: %fs, %s", Ticks<SecondsDouble>(now - peer.m_ping_start.load()), node_to.DisconnectMsg());
5462 node_to.fDisconnect = true;
5463 return;
5464 }
5465 5466 bool pingSend = false;
5467 5468 if (peer.m_ping_queued) {
5469 // RPC ping request by user
5470 pingSend = true;
5471 }
5472 5473 if (peer.m_ping_nonce_sent == 0 && now > peer.m_ping_start.load() + PING_INTERVAL) {
5474 // Ping automatically sent as a latency probe & keepalive.
5475 pingSend = true;
5476 }
5477 5478 if (pingSend) {
5479 uint64_t nonce;
5480 do {
5481 nonce = FastRandomContext().rand64();
5482 } while (nonce == 0);
5483 peer.m_ping_queued = false;
5484 peer.m_ping_start = now;
5485 if (node_to.GetCommonVersion() > BIP0031_VERSION) {
5486 peer.m_ping_nonce_sent = nonce;
5487 MakeAndPushMessage(node_to, NetMsgType::PING, nonce);
5488 } else {
5489 // Peer is too old to support ping message type with nonce, pong will never arrive.
5490 peer.m_ping_nonce_sent = 0;
5491 MakeAndPushMessage(node_to, NetMsgType::PING);
5492 }
5493 }
5494 }
5495 5496 void PeerManagerImpl::MaybeSendAddr(CNode& node, Peer& peer, std::chrono::microseconds current_time)
5497 {
5498 // Nothing to do for non-address-relay peers
5499 if (!peer.m_addr_relay_enabled) return;
5500 5501 LOCK(peer.m_addr_send_times_mutex);
5502 // Periodically advertise our local address to the peer.
5503 if (fListen && !m_chainman.IsInitialBlockDownload() &&
5504 peer.m_next_local_addr_send < current_time) {
5505 // If we've sent before, clear the bloom filter for the peer, so that our
5506 // self-announcement will actually go out.
5507 // This might be unnecessary if the bloom filter has already rolled
5508 // over since our last self-announcement, but there is only a small
5509 // bandwidth cost that we can incur by doing this (which happens
5510 // once a day on average).
5511 if (peer.m_next_local_addr_send != 0us) {
5512 peer.m_addr_known->reset();
5513 }
5514 if (std::optional<CService> local_service = GetLocalAddrForPeer(node)) {
5515 CAddress local_addr{*local_service, peer.m_our_services, Now<NodeSeconds>()};
5516 if (peer.m_next_local_addr_send == 0us) {
5517 // Send the initial self-announcement in its own message. This makes sure
5518 // rate-limiting with limited start-tokens doesn't ignore it if the first
5519 // message ends up containing multiple addresses.
5520 if (IsAddrCompatible(peer, local_addr)) {
5521 std::vector<CAddress> self_announcement{local_addr};
5522 if (peer.m_wants_addrv2) {
5523 MakeAndPushMessage(node, NetMsgType::ADDRV2, CAddress::V2_NETWORK(self_announcement));
5524 } else {
5525 MakeAndPushMessage(node, NetMsgType::ADDR, CAddress::V1_NETWORK(self_announcement));
5526 }
5527 }
5528 } else {
5529 // All later self-announcements are sent together with the other addresses.
5530 PushAddress(peer, local_addr);
5531 }
5532 }
5533 peer.m_next_local_addr_send = current_time + m_rng.rand_exp_duration(AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
5534 }
5535 5536 // We sent an `addr` message to this peer recently. Nothing more to do.
5537 if (current_time <= peer.m_next_addr_send) return;
5538 5539 peer.m_next_addr_send = current_time + m_rng.rand_exp_duration(AVG_ADDRESS_BROADCAST_INTERVAL);
5540 5541 if (!Assume(peer.m_addrs_to_send.size() <= MAX_ADDR_TO_SEND)) {
5542 // Should be impossible since we always check size before adding to
5543 // m_addrs_to_send. Recover by trimming the vector.
5544 peer.m_addrs_to_send.resize(MAX_ADDR_TO_SEND);
5545 }
5546 5547 // Remove addr records that the peer already knows about, and add new
5548 // addrs to the m_addr_known filter on the same pass.
5549 auto addr_already_known = [&peer](const CAddress& addr) EXCLUSIVE_LOCKS_REQUIRED(g_msgproc_mutex) {
5550 bool ret = peer.m_addr_known->contains(addr.GetKey());
5551 if (!ret) peer.m_addr_known->insert(addr.GetKey());
5552 return ret;
5553 };
5554 peer.m_addrs_to_send.erase(std::remove_if(peer.m_addrs_to_send.begin(), peer.m_addrs_to_send.end(), addr_already_known),
5555 peer.m_addrs_to_send.end());
5556 5557 // No addr messages to send
5558 if (peer.m_addrs_to_send.empty()) return;
5559 5560 if (peer.m_wants_addrv2) {
5561 MakeAndPushMessage(node, NetMsgType::ADDRV2, CAddress::V2_NETWORK(peer.m_addrs_to_send));
5562 } else {
5563 MakeAndPushMessage(node, NetMsgType::ADDR, CAddress::V1_NETWORK(peer.m_addrs_to_send));
5564 }
5565 peer.m_addrs_to_send.clear();
5566 5567 // we only send the big addr message once
5568 if (peer.m_addrs_to_send.capacity() > 40) {
5569 peer.m_addrs_to_send.shrink_to_fit();
5570 }
5571 }
5572 5573 void PeerManagerImpl::MaybeSendSendHeaders(CNode& node, Peer& peer)
5574 {
5575 // Delay sending SENDHEADERS (BIP 130) until we're done with an
5576 // initial-headers-sync with this peer. Receiving headers announcements for
5577 // new blocks while trying to sync their headers chain is problematic,
5578 // because of the state tracking done.
5579 if (!peer.m_sent_sendheaders && node.GetCommonVersion() >= SENDHEADERS_VERSION) {
5580 LOCK(cs_main);
5581 CNodeState &state = *State(node.GetId());
5582 if (state.pindexBestKnownBlock != nullptr &&
5583 state.pindexBestKnownBlock->nChainWork > m_chainman.MinimumChainWork()) {
5584 // Tell our peer we prefer to receive headers rather than inv's
5585 // We send this to non-NODE NETWORK peers as well, because even
5586 // non-NODE NETWORK peers can announce blocks (such as pruning
5587 // nodes)
5588 MakeAndPushMessage(node, NetMsgType::SENDHEADERS);
5589 peer.m_sent_sendheaders = true;
5590 }
5591 }
5592 }
5593 5594 void PeerManagerImpl::MaybeSendFeefilter(CNode& pto, Peer& peer, std::chrono::microseconds current_time)
5595 {
5596 if (m_opts.ignore_incoming_txs) return;
5597 if (pto.GetCommonVersion() < FEEFILTER_VERSION) return;
5598 // peers with the forcerelay permission should not filter txs to us
5599 if (pto.HasPermission(NetPermissionFlags::ForceRelay)) return;
5600 // Don't send feefilter messages to outbound block-relay-only peers since they should never announce
5601 // transactions to us, regardless of feefilter state.
5602 if (pto.IsBlockOnlyConn()) return;
5603 5604 CAmount currentFilter = m_mempool.GetMinFee().GetFeePerK();
5605 5606 if (m_chainman.IsInitialBlockDownload()) {
5607 // Received tx-inv messages are discarded when the active
5608 // chainstate is in IBD, so tell the peer to not send them.
5609 currentFilter = MAX_MONEY;
5610 } else {
5611 static const CAmount MAX_FILTER{m_fee_filter_rounder.round(MAX_MONEY)};
5612 if (peer.m_fee_filter_sent == MAX_FILTER) {
5613 // Send the current filter if we sent MAX_FILTER previously
5614 // and made it out of IBD.
5615 peer.m_next_send_feefilter = 0us;
5616 }
5617 }
5618 if (current_time > peer.m_next_send_feefilter) {
5619 CAmount filterToSend = m_fee_filter_rounder.round(currentFilter);
5620 // We always have a fee filter of at least the min relay fee
5621 filterToSend = std::max(filterToSend, m_mempool.m_opts.min_relay_feerate.GetFeePerK());
5622 if (filterToSend != peer.m_fee_filter_sent) {
5623 MakeAndPushMessage(pto, NetMsgType::FEEFILTER, filterToSend);
5624 peer.m_fee_filter_sent = filterToSend;
5625 }
5626 peer.m_next_send_feefilter = current_time + m_rng.rand_exp_duration(AVG_FEEFILTER_BROADCAST_INTERVAL);
5627 }
5628 // If the fee filter has changed substantially and it's still more than MAX_FEEFILTER_CHANGE_DELAY
5629 // until scheduled broadcast, then move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY.
5630 else if (current_time + MAX_FEEFILTER_CHANGE_DELAY < peer.m_next_send_feefilter &&
5631 (currentFilter < 3 * peer.m_fee_filter_sent / 4 || currentFilter > 4 * peer.m_fee_filter_sent / 3)) {
5632 peer.m_next_send_feefilter = current_time + m_rng.randrange<std::chrono::microseconds>(MAX_FEEFILTER_CHANGE_DELAY);
5633 }
5634 }
5635 5636 namespace {
5637 class CompareInvMempoolOrder
5638 {
5639 const CTxMemPool* m_mempool;
5640 public:
5641 explicit CompareInvMempoolOrder(CTxMemPool* mempool) : m_mempool{mempool} {}
5642 5643 bool operator()(std::set<Wtxid>::iterator a, std::set<Wtxid>::iterator b)
5644 {
5645 /* As std::make_heap produces a max-heap, we want the entries with the
5646 * higher mining score to sort later. */
5647 return m_mempool->CompareMiningScoreWithTopology(*b, *a);
5648 }
5649 };
5650 } // namespace
5651 5652 bool PeerManagerImpl::RejectIncomingTxs(const CNode& peer) const
5653 {
5654 // block-relay-only peers may never send txs to us
5655 if (peer.IsBlockOnlyConn()) return true;
5656 if (peer.IsFeelerConn()) return true;
5657 // In -blocksonly mode, peers need the 'relay' permission to send txs to us
5658 if (m_opts.ignore_incoming_txs && !peer.HasPermission(NetPermissionFlags::Relay)) return true;
5659 return false;
5660 }
5661 5662 void PeerManagerImpl::ProcessPong(CNode& pfrom, Peer& peer, const NodeClock::time_point ping_end, DataStream& vRecv)
5663 {
5664 uint64_t nonce = 0;
5665 const size_t nAvail{vRecv.size()};
5666 bool bPingFinished = false;
5667 std::string sProblem;
5668 5669 if (nAvail >= sizeof(nonce)) {
5670 vRecv >> nonce;
5671 5672 // Only process pong message if there is an outstanding ping (old ping without nonce should never pong)
5673 if (peer.m_ping_nonce_sent != 0) {
5674 if (nonce == peer.m_ping_nonce_sent) {
5675 // Matching pong received, this ping is no longer outstanding
5676 bPingFinished = true;
5677 const auto ping_time = ping_end - peer.m_ping_start.load();
5678 if (ping_time.count() >= 0) {
5679 // Let connman know about this successful ping-pong
5680 pfrom.PongReceived(ping_time);
5681 if (pfrom.IsPrivateBroadcastConn()) {
5682 m_tx_for_private_broadcast.NodeConfirmedReception(pfrom.GetId());
5683 LogDebug(BCLog::PRIVBROADCAST, "Got a PONG (the transaction will probably reach the network), marking for disconnect, %s",
5684 pfrom.LogPeer());
5685 pfrom.fDisconnect = true;
5686 }
5687 } else {
5688 // This should never happen
5689 sProblem = "Timing mishap";
5690 }
5691 } else {
5692 // Nonce mismatches are normal when pings are overlapping
5693 sProblem = "Nonce mismatch";
5694 if (nonce == 0) {
5695 // This is most likely a bug in another implementation somewhere; cancel this ping
5696 bPingFinished = true;
5697 sProblem = "Nonce zero";
5698 }
5699 }
5700 } else {
5701 sProblem = "Unsolicited pong without ping";
5702 }
5703 } else {
5704 // This is most likely a bug in another implementation somewhere; cancel this ping
5705 bPingFinished = true;
5706 sProblem = "Short payload";
5707 }
5708 5709 if (!(sProblem.empty())) {
5710 LogDebug(BCLog::NET, "pong peer=%d: %s, %x expected, %x received, %u bytes\n",
5711 pfrom.GetId(),
5712 sProblem,
5713 peer.m_ping_nonce_sent,
5714 nonce,
5715 nAvail);
5716 }
5717 if (bPingFinished) {
5718 peer.m_ping_nonce_sent = 0;
5719 }
5720 }
5721 5722 bool PeerManagerImpl::SetupAddressRelay(const CNode& node, Peer& peer)
5723 {
5724 // We don't participate in addr relay with outbound block-relay-only
5725 // connections to prevent providing adversaries with the additional
5726 // information of addr traffic to infer the link.
5727 if (node.IsBlockOnlyConn()) return false;
5728 5729 // We don't participate in addr relay with feeler connections because
5730 // they are disconnected shortly after the handshake completes,
5731 // before the node will receive the addr response.
5732 if (node.IsFeelerConn()) return false;
5733 5734 if (!peer.m_addr_relay_enabled.exchange(true)) {
5735 // During version message processing (non-block-relay-only outbound peers)
5736 // or on first addr-related message we have received (inbound peers), initialize
5737 // m_addr_known.
5738 peer.m_addr_known = std::make_unique<CRollingBloomFilter>(5000, 0.001);
5739 }
5740 5741 return true;
5742 }
5743 5744 void PeerManagerImpl::ProcessAddrs(std::string_view msg_type, CNode& pfrom, Peer& peer, std::vector<CAddress>&& vAddr, const std::atomic<bool>& interruptMsgProc)
5745 {
5746 AssertLockNotHeld(m_peer_mutex);
5747 AssertLockHeld(g_msgproc_mutex);
5748 5749 if (!SetupAddressRelay(pfrom, peer)) {
5750 LogDebug(BCLog::NET, "ignoring %s message from %s peer=%d\n", msg_type, pfrom.ConnectionTypeAsString(), pfrom.GetId());
5751 return;
5752 }
5753 5754 if (vAddr.size() > MAX_ADDR_TO_SEND)
5755 {
5756 Misbehaving(peer, strprintf("%s message size = %u", msg_type, vAddr.size()));
5757 return;
5758 }
5759 5760 // Store the new addresses
5761 std::vector<CAddress> vAddrOk;
5762 5763 // Update/increment addr rate limiting bucket.
5764 const auto current_time{NodeClock::now()};
5765 if (peer.m_addr_token_bucket < MAX_ADDR_PROCESSING_TOKEN_BUCKET) {
5766 // Don't increment bucket if it's already full
5767 const auto time_diff{current_time - peer.m_addr_token_timestamp};
5768 const double increment{std::max(Ticks<SecondsDouble>(time_diff), 0.0) * MAX_ADDR_RATE_PER_SECOND};
5769 peer.m_addr_token_bucket = std::min<double>(peer.m_addr_token_bucket + increment, MAX_ADDR_PROCESSING_TOKEN_BUCKET);
5770 }
5771 peer.m_addr_token_timestamp = current_time;
5772 5773 const bool rate_limited = !pfrom.HasPermission(NetPermissionFlags::Addr);
5774 uint64_t num_proc = 0;
5775 uint64_t num_rate_limit = 0;
5776 std::shuffle(vAddr.begin(), vAddr.end(), m_rng);
5777 for (CAddress& addr : vAddr)
5778 {
5779 if (interruptMsgProc)
5780 return;
5781 5782 // Apply rate limiting.
5783 if (peer.m_addr_token_bucket < 1.0) {
5784 if (rate_limited) {
5785 ++num_rate_limit;
5786 continue;
5787 }
5788 } else {
5789 peer.m_addr_token_bucket -= 1.0;
5790 }
5791 // We only bother storing full nodes, though this may include
5792 // things which we would not make an outbound connection to, in
5793 // part because we may make feeler connections to them.
5794 if (!MayHaveUsefulAddressDB(addr.nServices) && !HasAllDesirableServiceFlags(addr.nServices))
5795 continue;
5796 5797 if (addr.nTime <= NodeSeconds{100000000s} || addr.nTime > current_time + 10min) {
5798 addr.nTime = std::chrono::time_point_cast<std::chrono::seconds>(current_time - 5 * 24h);
5799 }
5800 AddAddressKnown(peer, addr);
5801 if (m_banman && (m_banman->IsDiscouraged(addr) || m_banman->IsBanned(addr))) {
5802 // Do not process banned/discouraged addresses beyond remembering we received them
5803 continue;
5804 }
5805 ++num_proc;
5806 const bool reachable{g_reachable_nets.Contains(addr)};
5807 if (addr.nTime > current_time - 10min && !peer.m_getaddr_sent && vAddr.size() <= 10 && addr.IsRoutable()) {
5808 // Relay to a limited number of other nodes
5809 RelayAddress(pfrom.GetId(), addr, reachable);
5810 }
5811 // Do not store addresses outside our network
5812 if (reachable) {
5813 vAddrOk.push_back(addr);
5814 }
5815 }
5816 peer.m_addr_processed += num_proc;
5817 peer.m_addr_rate_limited += num_rate_limit;
5818 LogDebug(BCLog::NET, "Received addr: %u addresses (%u processed, %u rate-limited) from peer=%d\n",
5819 vAddr.size(), num_proc, num_rate_limit, pfrom.GetId());
5820 5821 m_addrman.Add(vAddrOk, pfrom.addr, /*time_penalty=*/2h);
5822 if (vAddr.size() < 1000) peer.m_getaddr_sent = false;
5823 5824 // AddrFetch: Require multiple addresses to avoid disconnecting on self-announcements
5825 if (pfrom.IsAddrFetchConn() && vAddr.size() > 1) {
5826 LogDebug(BCLog::NET, "addrfetch connection completed, %s", pfrom.DisconnectMsg());
5827 pfrom.fDisconnect = true;
5828 }
5829 }
5830 5831 bool PeerManagerImpl::SendMessages(CNode& node)
5832 {
5833 AssertLockNotHeld(m_tx_download_mutex);
5834 AssertLockHeld(g_msgproc_mutex);
5835 5836 PeerRef maybe_peer{GetPeerRef(node.GetId())};
5837 if (!maybe_peer) return false;
5838 Peer& peer{*maybe_peer};
5839 const Consensus::Params& consensusParams = m_chainparams.GetConsensus();
5840 5841 // We must call MaybeDiscourageAndDisconnect first, to ensure that we'll
5842 // disconnect misbehaving peers even before the version handshake is complete.
5843 if (MaybeDiscourageAndDisconnect(node, peer)) return true;
5844 5845 // Initiate version handshake for outbound connections
5846 if (!node.IsInboundConn() && !peer.m_outbound_version_message_sent) {
5847 PushNodeVersion(node, peer);
5848 peer.m_outbound_version_message_sent = true;
5849 }
5850 5851 // Don't send anything until the version handshake is complete
5852 if (!node.fSuccessfullyConnected || node.fDisconnect)
5853 return true;
5854 5855 const auto now{NodeClock::now()};
5856 const auto current_time{GetTime<std::chrono::microseconds>()};
5857 5858 // The logic below does not apply to private broadcast peers, so skip it.
5859 // Also in CConnman::PushMessage() we make sure that unwanted messages are
5860 // not sent. This here is just an optimization.
5861 if (node.IsPrivateBroadcastConn()) {
5862 if (node.m_connected + PRIVATE_BROADCAST_MAX_CONNECTION_LIFETIME < now) {
5863 LogDebug(BCLog::PRIVBROADCAST, "Disconnecting: did not complete the transaction send within %d seconds, %s",
5864 count_seconds(PRIVATE_BROADCAST_MAX_CONNECTION_LIFETIME), node.LogPeer());
5865 node.fDisconnect = true;
5866 }
5867 return true;
5868 }
5869 5870 if (node.IsAddrFetchConn() && now - node.m_connected > 10 * AVG_ADDRESS_BROADCAST_INTERVAL) {
5871 LogDebug(BCLog::NET, "addrfetch connection timeout, %s", node.DisconnectMsg());
5872 node.fDisconnect = true;
5873 return true;
5874 }
5875 5876 MaybeSendPing(node, peer, now);
5877 5878 // MaybeSendPing may have marked peer for disconnection
5879 if (node.fDisconnect) return true;
5880 5881 MaybeSendAddr(node, peer, current_time);
5882 5883 MaybeSendSendHeaders(node, peer);
5884 5885 {
5886 LOCK(cs_main);
5887 5888 CNodeState &state = *State(node.GetId());
5889 5890 // Start block sync
5891 if (m_chainman.m_best_header == nullptr) {
5892 m_chainman.m_best_header = m_chainman.ActiveChain().Tip();
5893 }
5894 5895 // Determine whether we might try initial headers sync or parallel
5896 // block download from this peer -- this mostly affects behavior while
5897 // in IBD (once out of IBD, we sync from all peers).
5898 bool sync_blocks_and_headers_from_peer = false;
5899 if (state.fPreferredDownload) {
5900 sync_blocks_and_headers_from_peer = true;
5901 } else if (CanServeBlocks(peer) && !node.IsAddrFetchConn()) {
5902 // Typically this is an inbound peer. If we don't have any outbound
5903 // peers, or if we aren't downloading any blocks from such peers,
5904 // then allow block downloads from this peer, too.
5905 // We prefer downloading blocks from outbound peers to avoid
5906 // putting undue load on (say) some home user who is just making
5907 // outbound connections to the network, but if our only source of
5908 // the latest blocks is from an inbound peer, we have to be sure to
5909 // eventually download it (and not just wait indefinitely for an
5910 // outbound peer to have it).
5911 if (m_num_preferred_download_peers == 0 || mapBlocksInFlight.empty()) {
5912 sync_blocks_and_headers_from_peer = true;
5913 }
5914 }
5915 5916 if (!state.fSyncStarted && CanServeBlocks(peer) && !m_chainman.m_blockman.LoadingBlocks()) {
5917 // Only actively request headers from a single peer, unless we're close to today.
5918 if ((nSyncStarted == 0 && sync_blocks_and_headers_from_peer) || m_chainman.m_best_header->Time() > NodeClock::now() - 24h) {
5919 const CBlockIndex* pindexStart = m_chainman.m_best_header;
5920 /* If possible, start at the block preceding the currently
5921 best known header. This ensures that we always get a
5922 non-empty list of headers back as long as the peer
5923 is up-to-date. With a non-empty response, we can initialise
5924 the peer's known best block. This wouldn't be possible
5925 if we requested starting at m_chainman.m_best_header and
5926 got back an empty response. */
5927 if (pindexStart->pprev)
5928 pindexStart = pindexStart->pprev;
5929 if (MaybeSendGetHeaders(node, GetLocator(pindexStart), peer)) {
5930 LogDebug(BCLog::NET, "initial getheaders (%d) to peer=%d", pindexStart->nHeight, node.GetId());
5931 5932 state.fSyncStarted = true;
5933 peer.m_headers_sync_timeout = current_time + HEADERS_DOWNLOAD_TIMEOUT_BASE +
5934 (
5935 // Convert HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER to microseconds before scaling
5936 // to maintain precision
5937 std::chrono::microseconds{HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER} *
5938 Ticks<std::chrono::seconds>(NodeClock::now() - m_chainman.m_best_header->Time()) / consensusParams.nPowTargetSpacing
5939 );
5940 nSyncStarted++;
5941 }
5942 }
5943 }
5944 5945 //
5946 // Try sending block announcements via headers
5947 //
5948 {
5949 // If we have no more than MAX_BLOCKS_TO_ANNOUNCE in our
5950 // list of block hashes we're relaying, and our peer wants
5951 // headers announcements, then find the first header
5952 // not yet known to our peer but would connect, and send.
5953 // If no header would connect, or if we have too many
5954 // blocks, or if the peer doesn't want headers, just
5955 // add all to the inv queue.
5956 LOCK(peer.m_block_inv_mutex);
5957 std::vector<CBlock> vHeaders;
5958 bool fRevertToInv = ((!peer.m_prefers_headers &&
5959 (!state.m_requested_hb_cmpctblocks || peer.m_blocks_for_headers_relay.size() > 1)) ||
5960 peer.m_blocks_for_headers_relay.size() > MAX_BLOCKS_TO_ANNOUNCE);
5961 const CBlockIndex *pBestIndex = nullptr; // last header queued for delivery
5962 ProcessBlockAvailability(node.GetId()); // ensure pindexBestKnownBlock is up-to-date
5963 5964 if (!fRevertToInv) {
5965 bool fFoundStartingHeader = false;
5966 // Try to find first header that our peer doesn't have, and
5967 // then send all headers past that one. If we come across any
5968 // headers that aren't on m_chainman.ActiveChain(), give up.
5969 for (const uint256& hash : peer.m_blocks_for_headers_relay) {
5970 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(hash);
5971 assert(pindex);
5972 if (m_chainman.ActiveChain()[pindex->nHeight] != pindex) {
5973 // Bail out if we reorged away from this block
5974 fRevertToInv = true;
5975 break;
5976 }
5977 if (pBestIndex != nullptr && pindex->pprev != pBestIndex) {
5978 // This means that the list of blocks to announce don't
5979 // connect to each other.
5980 // This shouldn't really be possible to hit during
5981 // regular operation (because reorgs should take us to
5982 // a chain that has some block not on the prior chain,
5983 // which should be caught by the prior check), but one
5984 // way this could happen is by using invalidateblock /
5985 // reconsiderblock repeatedly on the tip, causing it to
5986 // be added multiple times to m_blocks_for_headers_relay.
5987 // Robustly deal with this rare situation by reverting
5988 // to an inv.
5989 fRevertToInv = true;
5990 break;
5991 }
5992 pBestIndex = pindex;
5993 if (fFoundStartingHeader) {
5994 // add this to the headers message
5995 vHeaders.emplace_back(pindex->GetBlockHeader());
5996 } else if (PeerHasHeader(&state, pindex)) {
5997 continue; // keep looking for the first new block
5998 } else if (pindex->pprev == nullptr || PeerHasHeader(&state, pindex->pprev)) {
5999 // Peer doesn't have this header but they do have the prior one.
6000 // Start sending headers.
6001 fFoundStartingHeader = true;
6002 vHeaders.emplace_back(pindex->GetBlockHeader());
6003 } else {
6004 // Peer doesn't have this header or the prior one -- nothing will
6005 // connect, so bail out.
6006 fRevertToInv = true;
6007 break;
6008 }
6009 }
6010 }
6011 if (!fRevertToInv && !vHeaders.empty()) {
6012 if (vHeaders.size() == 1 && state.m_requested_hb_cmpctblocks) {
6013 // We only send up to 1 block as header-and-ids, as otherwise
6014 // probably means we're doing an initial-ish-sync or they're slow
6015 LogDebug(BCLog::NET, "%s sending header-and-ids %s to peer=%d\n", __func__,
6016 vHeaders.front().GetHash().ToString(), node.GetId());
6017 6018 std::optional<CSerializedNetMsg> cached_cmpctblock_msg;
6019 {
6020 LOCK(m_most_recent_block_mutex);
6021 if (m_most_recent_block_hash == pBestIndex->GetBlockHash()) {
6022 cached_cmpctblock_msg = NetMsg::Make(NetMsgType::CMPCTBLOCK, *m_most_recent_compact_block);
6023 }
6024 }
6025 if (cached_cmpctblock_msg.has_value()) {
6026 PushMessage(node, std::move(cached_cmpctblock_msg.value()));
6027 } else {
6028 CBlock block;
6029 const bool ret{m_chainman.m_blockman.ReadBlock(block, *pBestIndex)};
6030 assert(ret);
6031 CBlockHeaderAndShortTxIDs cmpctblock{block, m_rng.rand64()};
6032 MakeAndPushMessage(node, NetMsgType::CMPCTBLOCK, cmpctblock);
6033 }
6034 state.pindexBestHeaderSent = pBestIndex;
6035 } else if (peer.m_prefers_headers) {
6036 if (vHeaders.size() > 1) {
6037 LogDebug(BCLog::NET, "%s: %u headers, range (%s, %s), to peer=%d\n", __func__,
6038 vHeaders.size(),
6039 vHeaders.front().GetHash().ToString(),
6040 vHeaders.back().GetHash().ToString(), node.GetId());
6041 } else {
6042 LogDebug(BCLog::NET, "%s: sending header %s to peer=%d\n", __func__,
6043 vHeaders.front().GetHash().ToString(), node.GetId());
6044 }
6045 MakeAndPushMessage(node, NetMsgType::HEADERS, TX_WITH_WITNESS(vHeaders));
6046 state.pindexBestHeaderSent = pBestIndex;
6047 } else
6048 fRevertToInv = true;
6049 }
6050 if (fRevertToInv) {
6051 // If falling back to using an inv, just try to inv the tip.
6052 // The last entry in m_blocks_for_headers_relay was our tip at some point
6053 // in the past.
6054 if (!peer.m_blocks_for_headers_relay.empty()) {
6055 const uint256& hashToAnnounce = peer.m_blocks_for_headers_relay.back();
6056 const CBlockIndex* pindex = m_chainman.m_blockman.LookupBlockIndex(hashToAnnounce);
6057 assert(pindex);
6058 6059 // Warn if we're announcing a block that is not on the main chain.
6060 // This should be very rare and could be optimized out.
6061 // Just log for now.
6062 if (m_chainman.ActiveChain()[pindex->nHeight] != pindex) {
6063 LogDebug(BCLog::NET, "Announcing block %s not on main chain (tip=%s)\n",
6064 hashToAnnounce.ToString(), m_chainman.ActiveChain().Tip()->GetBlockHash().ToString());
6065 }
6066 6067 // If the peer's chain has this block, don't inv it back.
6068 if (!PeerHasHeader(&state, pindex)) {
6069 peer.m_blocks_for_inv_relay.push_back(hashToAnnounce);
6070 LogDebug(BCLog::NET, "%s: sending inv peer=%d hash=%s\n", __func__,
6071 node.GetId(), hashToAnnounce.ToString());
6072 }
6073 }
6074 }
6075 peer.m_blocks_for_headers_relay.clear();
6076 }
6077 6078 //
6079 // Message: inventory
6080 //
6081 std::vector<CInv> vInv;
6082 {
6083 LOCK(peer.m_block_inv_mutex);
6084 vInv.reserve(std::max<size_t>(peer.m_blocks_for_inv_relay.size(), INVENTORY_BROADCAST_TARGET));
6085 6086 // Add blocks
6087 for (const uint256& hash : peer.m_blocks_for_inv_relay) {
6088 vInv.emplace_back(MSG_BLOCK, hash);
6089 if (vInv.size() == MAX_INV_SZ) {
6090 MakeAndPushMessage(node, NetMsgType::INV, vInv);
6091 vInv.clear();
6092 }
6093 }
6094 peer.m_blocks_for_inv_relay.clear();
6095 }
6096 6097 if (auto tx_relay = peer.GetTxRelay(); tx_relay != nullptr) {
6098 LOCK(tx_relay->m_tx_inventory_mutex);
6099 // Check whether periodic sends should happen
6100 bool fSendTrickle = node.HasPermission(NetPermissionFlags::NoBan);
6101 if (tx_relay->m_next_inv_send_time < current_time) {
6102 fSendTrickle = true;
6103 if (node.IsInboundConn()) {
6104 tx_relay->m_next_inv_send_time = NextInvToInbounds(current_time, INBOUND_INVENTORY_BROADCAST_INTERVAL, node.m_network_key);
6105 } else {
6106 tx_relay->m_next_inv_send_time = current_time + m_rng.rand_exp_duration(OUTBOUND_INVENTORY_BROADCAST_INTERVAL);
6107 }
6108 }
6109 6110 // Time to send but the peer has requested we not relay transactions.
6111 if (fSendTrickle) {
6112 LOCK(tx_relay->m_bloom_filter_mutex);
6113 if (!tx_relay->m_relay_txs) tx_relay->m_tx_inventory_to_send.clear();
6114 }
6115 6116 // Respond to BIP35 mempool requests
6117 if (fSendTrickle && tx_relay->m_send_mempool) {
6118 auto vtxinfo = m_mempool.infoAll();
6119 tx_relay->m_send_mempool = false;
6120 const CFeeRate filterrate{tx_relay->m_fee_filter_received.load()};
6121 6122 LOCK(tx_relay->m_bloom_filter_mutex);
6123 6124 for (const auto& txinfo : vtxinfo) {
6125 const Txid& txid{txinfo.tx->GetHash()};
6126 const Wtxid& wtxid{txinfo.tx->GetWitnessHash()};
6127 const auto inv = peer.m_wtxid_relay ?
6128 CInv{MSG_WTX, wtxid.ToUint256()} :
6129 CInv{MSG_TX, txid.ToUint256()};
6130 tx_relay->m_tx_inventory_to_send.erase(wtxid);
6131 6132 // Don't send transactions that peers will not put into their mempool
6133 if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
6134 continue;
6135 }
6136 if (tx_relay->m_bloom_filter) {
6137 if (!tx_relay->m_bloom_filter->IsRelevantAndUpdate(*txinfo.tx)) continue;
6138 }
6139 tx_relay->m_tx_inventory_known_filter.insert(inv.hash);
6140 vInv.push_back(inv);
6141 if (vInv.size() == MAX_INV_SZ) {
6142 MakeAndPushMessage(node, NetMsgType::INV, vInv);
6143 vInv.clear();
6144 }
6145 }
6146 }
6147 6148 // Determine transactions to relay
6149 if (fSendTrickle) {
6150 // Produce a vector with all candidates for sending
6151 std::vector<std::set<Wtxid>::iterator> vInvTx;
6152 vInvTx.reserve(tx_relay->m_tx_inventory_to_send.size());
6153 for (std::set<Wtxid>::iterator it = tx_relay->m_tx_inventory_to_send.begin(); it != tx_relay->m_tx_inventory_to_send.end(); it++) {
6154 vInvTx.push_back(it);
6155 }
6156 const CFeeRate filterrate{tx_relay->m_fee_filter_received.load()};
6157 // Topologically and fee-rate sort the inventory we send for privacy and priority reasons.
6158 // A heap is used so that not all items need sorting if only a few are being sent.
6159 CompareInvMempoolOrder compareInvMempoolOrder(&m_mempool);
6160 std::make_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder);
6161 // No reason to drain out at many times the network's capacity,
6162 // especially since we have many peers and some will draw much shorter delays.
6163 unsigned int nRelayedTransactions = 0;
6164 LOCK(tx_relay->m_bloom_filter_mutex);
6165 size_t broadcast_max{INVENTORY_BROADCAST_TARGET + (tx_relay->m_tx_inventory_to_send.size()/1000)*5};
6166 broadcast_max = std::min<size_t>(INVENTORY_BROADCAST_MAX, broadcast_max);
6167 while (!vInvTx.empty() && nRelayedTransactions < broadcast_max) {
6168 // Fetch the top element from the heap
6169 std::pop_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder);
6170 std::set<Wtxid>::iterator it = vInvTx.back();
6171 vInvTx.pop_back();
6172 auto wtxid = *it;
6173 // Remove it from the to-be-sent set
6174 tx_relay->m_tx_inventory_to_send.erase(it);
6175 // Not in the mempool anymore? don't bother sending it.
6176 auto txinfo = m_mempool.info(wtxid);
6177 if (!txinfo.tx) {
6178 continue;
6179 }
6180 // `TxRelay::m_tx_inventory_known_filter` contains either txids or wtxids
6181 // depending on whether our peer supports wtxid-relay. Therefore, first
6182 // construct the inv and then use its hash for the filter check.
6183 const auto inv = peer.m_wtxid_relay ?
6184 CInv{MSG_WTX, wtxid.ToUint256()} :
6185 CInv{MSG_TX, txinfo.tx->GetHash().ToUint256()};
6186 // Check if not in the filter already
6187 if (tx_relay->m_tx_inventory_known_filter.contains(inv.hash)) {
6188 continue;
6189 }
6190 // Peer told you to not send transactions at that feerate? Don't bother sending it.
6191 if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
6192 continue;
6193 }
6194 if (tx_relay->m_bloom_filter && !tx_relay->m_bloom_filter->IsRelevantAndUpdate(*txinfo.tx)) continue;
6195 // Send
6196 vInv.push_back(inv);
6197 nRelayedTransactions++;
6198 if (vInv.size() == MAX_INV_SZ) {
6199 MakeAndPushMessage(node, NetMsgType::INV, vInv);
6200 vInv.clear();
6201 }
6202 tx_relay->m_tx_inventory_known_filter.insert(inv.hash);
6203 }
6204 6205 // Ensure we'll respond to GETDATA requests for anything we've just announced
6206 LOCK(m_mempool.cs);
6207 tx_relay->m_last_inv_sequence = m_mempool.GetSequence();
6208 }
6209 }
6210 if (!vInv.empty())
6211 MakeAndPushMessage(node, NetMsgType::INV, vInv);
6212 6213 // Detect whether we're stalling
6214 auto stalling_timeout = m_block_stalling_timeout.load();
6215 if (state.m_stalling_since.count() && state.m_stalling_since < current_time - stalling_timeout) {
6216 // Stalling only triggers when the block download window cannot move. During normal steady state,
6217 // the download window should be much larger than the to-be-downloaded set of blocks, so disconnection
6218 // should only happen during initial block download.
6219 LogInfo("Peer is stalling block download, %s", node.DisconnectMsg());
6220 node.fDisconnect = true;
6221 // Increase timeout for the next peer so that we don't disconnect multiple peers if our own
6222 // bandwidth is insufficient.
6223 const auto new_timeout = std::min(2 * stalling_timeout, BLOCK_STALLING_TIMEOUT_MAX);
6224 if (stalling_timeout != new_timeout && m_block_stalling_timeout.compare_exchange_strong(stalling_timeout, new_timeout)) {
6225 LogDebug(BCLog::NET, "Increased stalling timeout temporarily to %d seconds\n", count_seconds(new_timeout));
6226 }
6227 return true;
6228 }
6229 // In case there is a block that has been in flight from this peer for block_interval * (1 + 0.5 * N)
6230 // (with N the number of peers from which we're downloading validated blocks), disconnect due to timeout.
6231 // We compensate for other peers to prevent killing off peers due to our own downstream link
6232 // being saturated. We only count validated in-flight blocks so peers can't advertise non-existing block hashes
6233 // to unreasonably increase our timeout.
6234 if (state.vBlocksInFlight.size() > 0) {
6235 QueuedBlock &queuedBlock = state.vBlocksInFlight.front();
6236 int nOtherPeersWithValidatedDownloads = m_peers_downloading_from - 1;
6237 if (current_time > state.m_downloading_since + std::chrono::seconds{consensusParams.nPowTargetSpacing} * (BLOCK_DOWNLOAD_TIMEOUT_BASE + BLOCK_DOWNLOAD_TIMEOUT_PER_PEER * nOtherPeersWithValidatedDownloads)) {
6238 LogInfo("Timeout downloading block %s, %s", queuedBlock.pindex->GetBlockHash().ToString(), node.DisconnectMsg());
6239 node.fDisconnect = true;
6240 return true;
6241 }
6242 }
6243 // Check for headers sync timeouts
6244 if (state.fSyncStarted && peer.m_headers_sync_timeout < std::chrono::microseconds::max()) {
6245 // Detect whether this is a stalling initial-headers-sync peer
6246 if (m_chainman.m_best_header->Time() <= NodeClock::now() - 24h) {
6247 if (current_time > peer.m_headers_sync_timeout && nSyncStarted == 1 && (m_num_preferred_download_peers - state.fPreferredDownload >= 1)) {
6248 // Disconnect a peer (without NetPermissionFlags::NoBan permission) if it is our only sync peer,
6249 // and we have others we could be using instead.
6250 // Note: If all our peers are inbound, then we won't
6251 // disconnect our sync peer for stalling; we have bigger
6252 // problems if we can't get any outbound peers.
6253 if (!node.HasPermission(NetPermissionFlags::NoBan)) {
6254 LogInfo("Timeout downloading headers, %s", node.DisconnectMsg());
6255 node.fDisconnect = true;
6256 return true;
6257 } else {
6258 LogInfo("Timeout downloading headers from noban peer, not %s", node.DisconnectMsg());
6259 // Reset the headers sync state so that we have a
6260 // chance to try downloading from a different peer.
6261 // Note: this will also result in at least one more
6262 // getheaders message to be sent to
6263 // this peer (eventually).
6264 state.fSyncStarted = false;
6265 nSyncStarted--;
6266 peer.m_headers_sync_timeout = 0us;
6267 }
6268 }
6269 } else {
6270 // After we've caught up once, reset the timeout so we can't trigger
6271 // disconnect later.
6272 peer.m_headers_sync_timeout = std::chrono::microseconds::max();
6273 }
6274 }
6275 6276 // Check that outbound peers have reasonable chains
6277 // GetTime() is used by this anti-DoS logic so we can test this using mocktime
6278 ConsiderEviction(node, peer, GetTime<std::chrono::seconds>());
6279 6280 //
6281 // Message: getdata (blocks)
6282 //
6283 std::vector<CInv> vGetData;
6284 if (CanServeBlocks(peer) && ((sync_blocks_and_headers_from_peer && !IsLimitedPeer(peer)) || !m_chainman.IsInitialBlockDownload()) && state.vBlocksInFlight.size() < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
6285 std::vector<const CBlockIndex*> vToDownload;
6286 NodeId staller = -1;
6287 auto get_inflight_budget = [&state]() {
6288 return std::max(0, MAX_BLOCKS_IN_TRANSIT_PER_PEER - static_cast<int>(state.vBlocksInFlight.size()));
6289 };
6290 6291 // If there are multiple chainstates, download blocks for the
6292 // current chainstate first, to prioritize getting to network tip
6293 // before downloading historical blocks.
6294 FindNextBlocksToDownload(peer, get_inflight_budget(), vToDownload, staller);
6295 auto historical_blocks{m_chainman.GetHistoricalBlockRange()};
6296 if (historical_blocks && !IsLimitedPeer(peer)) {
6297 // If the first needed historical block is not an ancestor of the last,
6298 // we need to start requesting blocks from their last common ancestor.
6299 const CBlockIndex* from_tip = LastCommonAncestor(historical_blocks->first, historical_blocks->second);
6300 TryDownloadingHistoricalBlocks(
6301 peer,
6302 get_inflight_budget(),
6303 vToDownload, from_tip, historical_blocks->second);
6304 }
6305 for (const CBlockIndex *pindex : vToDownload) {
6306 uint32_t nFetchFlags = GetFetchFlags(peer);
6307 vGetData.emplace_back(MSG_BLOCK | nFetchFlags, pindex->GetBlockHash());
6308 BlockRequested(node.GetId(), *pindex);
6309 LogDebug(BCLog::NET, "Requesting block %s (%d) peer=%d\n", pindex->GetBlockHash().ToString(),
6310 pindex->nHeight, node.GetId());
6311 }
6312 if (state.vBlocksInFlight.empty() && staller != -1) {
6313 if (State(staller)->m_stalling_since == 0us) {
6314 State(staller)->m_stalling_since = current_time;
6315 LogDebug(BCLog::NET, "Stall started peer=%d\n", staller);
6316 }
6317 }
6318 }
6319 6320 //
6321 // Message: getdata (transactions)
6322 //
6323 {
6324 LOCK(m_tx_download_mutex);
6325 for (const GenTxid& gtxid : m_txdownloadman.GetRequestsToSend(node.GetId(), current_time)) {
6326 vGetData.emplace_back(gtxid.IsWtxid() ? MSG_WTX : (MSG_TX | GetFetchFlags(peer)), gtxid.ToUint256());
6327 if (vGetData.size() >= MAX_GETDATA_SZ) {
6328 MakeAndPushMessage(node, NetMsgType::GETDATA, vGetData);
6329 vGetData.clear();
6330 }
6331 }
6332 }
6333 6334 if (!vGetData.empty())
6335 MakeAndPushMessage(node, NetMsgType::GETDATA, vGetData);
6336 } // release cs_main
6337 MaybeSendFeefilter(node, peer, current_time);
6338 return true;
6339 }
6340