net.cpp raw
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 <bitcoin-build-config.h> // IWYU pragma: keep
7
8 #include <net.h>
9
10 #include <addrdb.h>
11 #include <addrman.h>
12 #include <banman.h>
13 #include <clientversion.h>
14 #include <common/args.h>
15 #include <common/netif.h>
16 #include <compat/compat.h>
17 #include <consensus/consensus.h>
18 #include <crypto/sha256.h>
19 #include <i2p.h>
20 #include <key.h>
21 #include <logging.h>
22 #include <memusage.h>
23 #include <net_permissions.h>
24 #include <netaddress.h>
25 #include <netbase.h>
26 #include <node/eviction.h>
27 #include <node/interface_ui.h>
28 #include <protocol.h>
29 #include <random.h>
30 #include <scheduler.h>
31 #include <util/fs.h>
32 #include <util/overflow.h>
33 #include <util/sock.h>
34 #include <util/strencodings.h>
35 #include <util/thread.h>
36 #include <util/threadinterrupt.h>
37 #include <util/trace.h>
38 #include <util/translation.h>
39 #include <util/vector.h>
40
41 #include <algorithm>
42 #include <array>
43 #include <cmath>
44 #include <cstdint>
45 #include <cstring>
46 #include <functional>
47 #include <optional>
48 #include <string_view>
49 #include <unordered_map>
50
51 TRACEPOINT_SEMAPHORE(net, closed_connection);
52 TRACEPOINT_SEMAPHORE(net, evicted_inbound_connection);
53 TRACEPOINT_SEMAPHORE(net, inbound_connection);
54 TRACEPOINT_SEMAPHORE(net, outbound_connection);
55 TRACEPOINT_SEMAPHORE(net, outbound_message);
56
57 /** Maximum number of block-relay-only anchor connections */
58 static constexpr size_t MAX_BLOCK_RELAY_ONLY_ANCHORS = 2;
59 static_assert (MAX_BLOCK_RELAY_ONLY_ANCHORS <= static_cast<size_t>(MAX_BLOCK_RELAY_ONLY_CONNECTIONS), "MAX_BLOCK_RELAY_ONLY_ANCHORS must not exceed MAX_BLOCK_RELAY_ONLY_CONNECTIONS.");
60 /** Anchor IP address database file name */
61 const char* const ANCHORS_DATABASE_FILENAME = "anchors.dat";
62
63 // How often to dump addresses to peers.dat
64 static constexpr std::chrono::minutes DUMP_PEERS_INTERVAL{15};
65
66 /** Number of DNS seeds to query when the number of connections is low. */
67 static constexpr int DNSSEEDS_TO_QUERY_AT_ONCE = 3;
68
69 /** Minimum number of outbound connections under which we will keep fetching our address seeds. */
70 static constexpr int SEED_OUTBOUND_CONNECTION_THRESHOLD = 2;
71
72 /** How long to delay before querying DNS seeds
73 *
74 * If we have more than THRESHOLD entries in addrman, then it's likely
75 * that we got those addresses from having previously connected to the P2P
76 * network, and that we'll be able to successfully reconnect to the P2P
77 * network via contacting one of them. So if that's the case, spend a
78 * little longer trying to connect to known peers before querying the
79 * DNS seeds.
80 */
81 static constexpr std::chrono::seconds DNSSEEDS_DELAY_FEW_PEERS{11};
82 static constexpr std::chrono::minutes DNSSEEDS_DELAY_MANY_PEERS{5};
83 static constexpr int DNSSEEDS_DELAY_PEER_THRESHOLD = 1000; // "many" vs "few" peers
84
85 /** The default timeframe for -maxuploadtarget. 1 day. */
86 static constexpr std::chrono::seconds MAX_UPLOAD_TIMEFRAME{60 * 60 * 24};
87
88 // A random time period (0 to 1 seconds) is added to feeler connections to prevent synchronization.
89 static constexpr auto FEELER_SLEEP_WINDOW{1s};
90
91 /** Frequency to attempt extra connections to reachable networks we're not connected to yet **/
92 static constexpr auto EXTRA_NETWORK_PEER_INTERVAL{5min};
93
94 /** Used to pass flags to the Bind() function */
95 enum BindFlags {
96 BF_NONE = 0,
97 BF_REPORT_ERROR = (1U << 0),
98 /**
99 * Do not call AddLocal() for our special addresses, e.g., for incoming
100 * Tor connections, to prevent gossiping them over the network.
101 */
102 BF_DONT_ADVERTISE = (1U << 1),
103 };
104
105 // The set of sockets cannot be modified while waiting
106 // The sleep time needs to be small to avoid new sockets stalling
107 static const uint64_t SELECT_TIMEOUT_MILLISECONDS = 50;
108
109 const std::string NET_MESSAGE_TYPE_OTHER = "*other*";
110
111 static const uint64_t RANDOMIZER_ID_NETGROUP = 0x6c0edd8036ef4036ULL; // SHA256("netgroup")[0:8]
112 static const uint64_t RANDOMIZER_ID_LOCALHOSTNONCE = 0xd93e69e2bbfa5735ULL; // SHA256("localhostnonce")[0:8]
113 static const uint64_t RANDOMIZER_ID_NETWORKKEY = 0x0e8a2b136c592a7dULL; // SHA256("networkkey")[0:8]
114 //
115 // Global state variables
116 //
117 bool fDiscover = true;
118 bool fListen = true;
119 GlobalMutex g_maplocalhost_mutex;
120 std::map<CNetAddr, LocalServiceInfo> mapLocalHost GUARDED_BY(g_maplocalhost_mutex);
121 std::string strSubVersion;
122
123 size_t CSerializedNetMsg::GetMemoryUsage() const noexcept
124 {
125 return sizeof(*this) + memusage::DynamicUsage(m_type) + memusage::DynamicUsage(data);
126 }
127
128 size_t CNetMessage::GetMemoryUsage() const noexcept
129 {
130 return sizeof(*this) + memusage::DynamicUsage(m_type) + m_recv.GetMemoryUsage();
131 }
132
133 void CConnman::AddAddrFetch(const std::string& strDest)
134 {
135 LOCK(m_addr_fetches_mutex);
136 m_addr_fetches.push_back(strDest);
137 }
138
139 uint16_t GetListenPort()
140 {
141 // If -bind= is provided with ":port" part, use that (first one if multiple are provided).
142 for (const std::string& bind_arg : gArgs.GetArgs("-bind")) {
143 constexpr uint16_t dummy_port = 0;
144
145 const std::optional<CService> bind_addr{Lookup(bind_arg, dummy_port, /*fAllowLookup=*/false)};
146 if (bind_addr.has_value() && bind_addr->GetPort() != dummy_port) return bind_addr->GetPort();
147 }
148
149 // Otherwise, if -whitebind= without NetPermissionFlags::NoBan is provided, use that
150 // (-whitebind= is required to have ":port").
151 for (const std::string& whitebind_arg : gArgs.GetArgs("-whitebind")) {
152 NetWhitebindPermissions whitebind;
153 bilingual_str error;
154 if (NetWhitebindPermissions::TryParse(whitebind_arg, whitebind, error)) {
155 if (!NetPermissions::HasFlag(whitebind.m_flags, NetPermissionFlags::NoBan)) {
156 return whitebind.m_service.GetPort();
157 }
158 }
159 }
160
161 // Otherwise, if -port= is provided, use that. Otherwise use the default port.
162 return static_cast<uint16_t>(gArgs.GetIntArg("-port", Params().GetDefaultPort()));
163 }
164
165 // Determine the "best" local address for a particular peer.
166 [[nodiscard]] static std::optional<CService> GetLocal(const CNode& peer)
167 {
168 if (!fListen) return std::nullopt;
169
170 std::optional<CService> addr;
171 int nBestScore = -1;
172 int nBestReachability = -1;
173 {
174 LOCK(g_maplocalhost_mutex);
175 for (const auto& [local_addr, local_service_info] : mapLocalHost) {
176 // For privacy reasons, don't advertise our privacy-network address
177 // to other networks and don't advertise our other-network address
178 // to privacy networks.
179 if (local_addr.GetNetwork() != peer.ConnectedThroughNetwork()
180 && (local_addr.IsPrivacyNet() || peer.IsConnectedThroughPrivacyNet())) {
181 continue;
182 }
183 const int nScore{local_service_info.nScore};
184 const int nReachability{local_addr.GetReachabilityFrom(peer.addr)};
185 if (nReachability > nBestReachability || (nReachability == nBestReachability && nScore > nBestScore)) {
186 addr.emplace(CService{local_addr, local_service_info.nPort});
187 nBestReachability = nReachability;
188 nBestScore = nScore;
189 }
190 }
191 }
192 return addr;
193 }
194
195 //! Convert the serialized seeds into usable address objects.
196 static std::vector<CAddress> ConvertSeeds(const std::vector<uint8_t> &vSeedsIn)
197 {
198 // It'll only connect to one or two seed nodes because once it connects,
199 // it'll get a pile of addresses with newer timestamps.
200 // Seed nodes are given a random 'last seen time' of between one and two
201 // weeks ago.
202 const auto one_week{7 * 24h};
203 std::vector<CAddress> vSeedsOut;
204 FastRandomContext rng;
205 ParamsStream s{SpanReader{vSeedsIn}, CAddress::V2_NETWORK};
206 while (!s.empty()) {
207 CService endpoint;
208 s >> endpoint;
209 CAddress addr{endpoint, SeedsServiceFlags()};
210 addr.nTime = rng.rand_uniform_delay(Now<NodeSeconds>() - one_week, -one_week);
211 LogDebug(BCLog::NET, "Added hardcoded seed: %s\n", addr.ToStringAddrPort());
212 vSeedsOut.push_back(addr);
213 }
214 return vSeedsOut;
215 }
216
217 // Determine the "best" local address for a particular peer.
218 // If none, return the unroutable 0.0.0.0 but filled in with
219 // the normal parameters, since the IP may be changed to a useful
220 // one by discovery.
221 CService GetLocalAddress(const CNode& peer)
222 {
223 return GetLocal(peer).value_or(CService{CNetAddr(), GetListenPort()});
224 }
225
226 static int GetnScore(const CService& addr)
227 {
228 LOCK(g_maplocalhost_mutex);
229 const auto it = mapLocalHost.find(addr);
230 return (it != mapLocalHost.end()) ? it->second.nScore : 0;
231 }
232
233 // Is our peer's addrLocal potentially useful as an external IP source?
234 [[nodiscard]] static bool IsPeerAddrLocalGood(CNode *pnode)
235 {
236 CService addrLocal = pnode->GetAddrLocal();
237 return fDiscover && pnode->addr.IsRoutable() && addrLocal.IsRoutable() &&
238 g_reachable_nets.Contains(addrLocal);
239 }
240
241 std::optional<CService> GetLocalAddrForPeer(CNode& node)
242 {
243 CService addrLocal{GetLocalAddress(node)};
244 // If discovery is enabled, sometimes give our peer the address it
245 // tells us that it sees us as in case it has a better idea of our
246 // address than we do.
247 FastRandomContext rng;
248 if (IsPeerAddrLocalGood(&node) && (!addrLocal.IsRoutable() ||
249 rng.randbits((GetnScore(addrLocal) > LOCAL_MANUAL) ? 3 : 1) == 0))
250 {
251 if (node.IsInboundConn()) {
252 // For inbound connections, assume both the address and the port
253 // as seen from the peer.
254 addrLocal = CService{node.GetAddrLocal()};
255 } else {
256 // For outbound connections, assume just the address as seen from
257 // the peer and leave the port in `addrLocal` as returned by
258 // `GetLocalAddress()` above. The peer has no way to observe our
259 // listening port when we have initiated the connection.
260 addrLocal.SetIP(node.GetAddrLocal());
261 }
262 }
263 if (addrLocal.IsRoutable()) {
264 LogDebug(BCLog::NET, "Advertising address %s to peer=%d\n", addrLocal.ToStringAddrPort(), node.GetId());
265 return addrLocal;
266 }
267 // Address is unroutable. Don't advertise.
268 return std::nullopt;
269 }
270
271 void ClearLocal()
272 {
273 LOCK(g_maplocalhost_mutex);
274 return mapLocalHost.clear();
275 }
276
277 // learn a new local address
278 bool AddLocal(const CService& addr_, int nScore)
279 {
280 CService addr{MaybeFlipIPv6toCJDNS(addr_)};
281
282 if (!addr.IsRoutable())
283 return false;
284
285 if (!fDiscover && nScore < LOCAL_MANUAL)
286 return false;
287
288 if (!g_reachable_nets.Contains(addr))
289 return false;
290
291 if (fLogIPs) {
292 LogInfo("AddLocal(%s,%i)\n", addr.ToStringAddrPort(), nScore);
293 }
294
295 {
296 LOCK(g_maplocalhost_mutex);
297 const auto [it, is_newly_added] = mapLocalHost.emplace(addr, LocalServiceInfo());
298 LocalServiceInfo &info = it->second;
299 if (is_newly_added || nScore >= info.nScore) {
300 info.nScore = SaturatingAdd(nScore, is_newly_added ? 0 : 1);
301 info.nPort = addr.GetPort();
302 }
303 }
304
305 return true;
306 }
307
308 bool AddLocal(const CNetAddr &addr, int nScore)
309 {
310 return AddLocal(CService(addr, GetListenPort()), nScore);
311 }
312
313 void RemoveLocal(const CService& addr)
314 {
315 LOCK(g_maplocalhost_mutex);
316 if (fLogIPs) {
317 LogInfo("RemoveLocal(%s)\n", addr.ToStringAddrPort());
318 }
319
320 mapLocalHost.erase(addr);
321 }
322
323 /** vote for a local address */
324 bool SeenLocal(const CService& addr)
325 {
326 LOCK(g_maplocalhost_mutex);
327 const auto it = mapLocalHost.find(addr);
328 if (it == mapLocalHost.end()) return false;
329 it->second.nScore = SaturatingAdd(it->second.nScore, 1);
330 return true;
331 }
332
333
334 /** check whether a given address is potentially local */
335 bool IsLocal(const CService& addr)
336 {
337 LOCK(g_maplocalhost_mutex);
338 return mapLocalHost.contains(addr);
339 }
340
341 bool CConnman::AlreadyConnectedToHost(std::string_view host) const
342 {
343 LOCK(m_nodes_mutex);
344 return std::ranges::any_of(m_nodes, [&host](CNode* node) { return node->m_addr_name == host; });
345 }
346
347 bool CConnman::AlreadyConnectedToAddressPort(const CService& addr_port) const
348 {
349 LOCK(m_nodes_mutex);
350 return std::ranges::any_of(m_nodes, [&addr_port](CNode* node) { return node->addr == addr_port; });
351 }
352
353 bool CConnman::AlreadyConnectedToAddress(const CNetAddr& addr) const
354 {
355 LOCK(m_nodes_mutex);
356 return std::ranges::any_of(m_nodes, [&addr](CNode* node) { return node->addr == addr; });
357 }
358
359 bool CConnman::CheckIncomingNonce(uint64_t nonce)
360 {
361 LOCK(m_nodes_mutex);
362 for (const CNode* pnode : m_nodes) {
363 // Omit private broadcast connections from this check to prevent this privacy attack:
364 // - We connect to a peer in an attempt to privately broadcast a transaction. From our
365 // VERSION message the peer deducts that this is a short-lived connection for
366 // broadcasting a transaction, takes our nonce and delays their VERACK.
367 // - The peer starts connecting to (clearnet) nodes and sends them a VERSION message
368 // which contains our nonce. If the peer manages to connect to us we would disconnect.
369 // - Upon a disconnect, the peer knows our clearnet address. They go back to the short
370 // lived privacy broadcast connection and continue with VERACK.
371 if (!pnode->fSuccessfullyConnected && !pnode->IsInboundConn() && !pnode->IsPrivateBroadcastConn() &&
372 pnode->GetLocalNonce() == nonce)
373 return false;
374 }
375 return true;
376 }
377
378 CNode* CConnman::ConnectNode(CAddress addrConnect,
379 const char* pszDest,
380 bool fCountFailure,
381 ConnectionType conn_type,
382 bool use_v2transport,
383 const std::optional<Proxy>& proxy_override)
384 {
385 AssertLockNotHeld(m_nodes_mutex);
386 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
387 assert(conn_type != ConnectionType::INBOUND);
388
389 if (pszDest == nullptr) {
390 if (IsLocal(addrConnect))
391 return nullptr;
392
393 // Look for an existing connection
394 if (AlreadyConnectedToAddressPort(addrConnect)) {
395 LogInfo("Failed to open new connection to %s, already connected", addrConnect.ToStringAddrPort());
396 return nullptr;
397 }
398 }
399
400 LogDebug(BCLog::NET, "trying %s connection (%s) to %s, lastseen=%.1fhrs\n",
401 use_v2transport ? "v2" : "v1",
402 ConnectionTypeAsString(conn_type),
403 pszDest ? pszDest : addrConnect.ToStringAddrPort(),
404 Ticks<HoursDouble>(pszDest ? 0h : Now<NodeSeconds>() - addrConnect.nTime));
405
406 // Resolve
407 const uint16_t default_port{pszDest != nullptr ? GetDefaultPort(pszDest) :
408 m_params.GetDefaultPort()};
409
410 // Collection of addresses to try to connect to: either all dns resolved addresses if a domain name (pszDest) is provided, or addrConnect otherwise.
411 std::vector<CAddress> connect_to{};
412 if (pszDest) {
413 std::vector<CService> resolved{Lookup(pszDest, default_port, fNameLookup && !HaveNameProxy(), 256)};
414 if (!resolved.empty()) {
415 std::shuffle(resolved.begin(), resolved.end(), FastRandomContext());
416 // If the connection is made by name, it can be the case that the name resolves to more than one address.
417 // We don't want to connect any more of them if we are already connected to one
418 for (const auto& r : resolved) {
419 addrConnect = CAddress{MaybeFlipIPv6toCJDNS(r), NODE_NONE};
420 if (!addrConnect.IsValid()) {
421 LogDebug(BCLog::NET, "Resolver returned invalid address %s for %s\n", addrConnect.ToStringAddrPort(), pszDest);
422 return nullptr;
423 }
424 // It is possible that we already have a connection to the IP/port pszDest resolved to.
425 // In that case, drop the connection that was just created.
426 if (AlreadyConnectedToAddressPort(addrConnect)) {
427 LogInfo("Not opening a connection to %s, already connected to %s\n", pszDest, addrConnect.ToStringAddrPort());
428 return nullptr;
429 }
430 // Add the address to the resolved addresses vector so we can try to connect to it later on
431 connect_to.push_back(addrConnect);
432 }
433 } else {
434 // For resolution via proxy
435 connect_to.push_back(addrConnect);
436 }
437 } else {
438 // Connect via addrConnect directly
439 connect_to.push_back(addrConnect);
440 }
441
442 // Connect
443 std::unique_ptr<Sock> sock;
444 CService addr_bind;
445 assert(!addr_bind.IsValid());
446 std::unique_ptr<i2p::sam::Session> i2p_transient_session;
447
448 for (auto& target_addr : connect_to) {
449 if (target_addr.IsValid()) {
450 const std::optional<Proxy> use_proxy{
451 proxy_override.has_value() ? proxy_override : GetProxy(target_addr.GetNetwork()),
452 };
453 bool proxyConnectionFailed = false;
454
455 if (target_addr.IsI2P() && use_proxy) {
456 i2p::Connection conn;
457 bool connected{false};
458
459 // If an I2P SAM session already exists, normally we would re-use it. But in the case of
460 // private broadcast we force a new transient session. A Connect() using m_i2p_sam_session
461 // would use our permanent I2P address as a source address.
462 if (m_i2p_sam_session && conn_type != ConnectionType::PRIVATE_BROADCAST) {
463 connected = m_i2p_sam_session->Connect(target_addr, conn, proxyConnectionFailed);
464 } else {
465 {
466 LOCK(m_unused_i2p_sessions_mutex);
467 if (m_unused_i2p_sessions.empty()) {
468 i2p_transient_session =
469 std::make_unique<i2p::sam::Session>(*use_proxy, m_interrupt_net);
470 } else {
471 i2p_transient_session.swap(m_unused_i2p_sessions.front());
472 m_unused_i2p_sessions.pop();
473 }
474 }
475 connected = i2p_transient_session->Connect(target_addr, conn, proxyConnectionFailed);
476 if (!connected) {
477 LOCK(m_unused_i2p_sessions_mutex);
478 if (m_unused_i2p_sessions.size() < MAX_UNUSED_I2P_SESSIONS_SIZE) {
479 m_unused_i2p_sessions.emplace(i2p_transient_session.release());
480 }
481 }
482 }
483
484 if (connected) {
485 sock = std::move(conn.sock);
486 addr_bind = conn.me;
487 }
488 } else if (use_proxy) {
489 LogDebug(BCLog::PROXY, "Using proxy: %s to connect to %s\n", use_proxy->ToString(), target_addr.ToStringAddrPort());
490 sock = ConnectThroughProxy(*use_proxy, target_addr.ToStringAddr(), target_addr.GetPort(), proxyConnectionFailed);
491 } else {
492 // No proxy needed (none set for target network). Private broadcast connections
493 // must always use a proxy, otherwise they would leak the originator's IP address.
494 if (Assume(conn_type != ConnectionType::PRIVATE_BROADCAST)) {
495 sock = ConnectDirectly(target_addr, conn_type == ConnectionType::MANUAL);
496 }
497 }
498 if (!proxyConnectionFailed) {
499 // If a connection to the node was attempted, and failure (if any) is not caused by a problem connecting to
500 // the proxy, mark this as an attempt.
501 addrman.get().Attempt(target_addr, fCountFailure);
502 }
503 } else if (pszDest) {
504 if (const auto name_proxy = GetNameProxy()) {
505 std::string host;
506 uint16_t port{default_port};
507 SplitHostPort(pszDest, port, host);
508 bool proxyConnectionFailed;
509 sock = ConnectThroughProxy(*name_proxy, host, port, proxyConnectionFailed);
510 }
511 }
512 // Check any other resolved address (if any) if we fail to connect
513 if (!sock) {
514 continue;
515 }
516
517 NetPermissionFlags permission_flags = NetPermissionFlags::None;
518 std::vector<NetWhitelistPermissions> whitelist_permissions = conn_type == ConnectionType::MANUAL ? vWhitelistedRangeOutgoing : std::vector<NetWhitelistPermissions>{};
519 AddWhitelistPermissionFlags(permission_flags, target_addr, whitelist_permissions);
520
521 // Add node
522 NodeId id = GetNewNodeId();
523 uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
524 if (!addr_bind.IsValid()) {
525 addr_bind = GetBindAddress(*sock);
526 }
527 uint64_t network_id = GetDeterministicRandomizer(RANDOMIZER_ID_NETWORKKEY)
528 .Write(target_addr.GetNetClass())
529 .Write(addr_bind.GetAddrBytes())
530 // For outbound connections, the port of the bound address is randomly
531 // assigned by the OS and would therefore not be useful for seeding.
532 .Write(0)
533 .Finalize();
534 CNode* pnode = new CNode(id,
535 std::move(sock),
536 target_addr,
537 CalculateKeyedNetGroup(target_addr),
538 nonce,
539 addr_bind,
540 pszDest ? pszDest : "",
541 conn_type,
542 /*inbound_onion=*/false,
543 network_id,
544 CNodeOptions{
545 .permission_flags = permission_flags,
546 .proxy_override = proxy_override,
547 .i2p_sam_session = std::move(i2p_transient_session),
548 .recv_flood_size = nReceiveFloodSize,
549 .use_v2transport = use_v2transport,
550 });
551 pnode->AddRef();
552
553 // We're making a new connection, harvest entropy from the time (and our peer count)
554 RandAddEvent((uint32_t)id);
555
556 return pnode;
557 }
558
559 return nullptr;
560 }
561
562 void CNode::CloseSocketDisconnect()
563 {
564 fDisconnect = true;
565 LOCK(m_sock_mutex);
566 if (m_sock) {
567 LogDebug(BCLog::NET, "Resetting socket for %s", LogPeer());
568 m_sock.reset();
569
570 TRACEPOINT(net, closed_connection,
571 GetId(),
572 m_addr_name.c_str(),
573 ConnectionTypeAsString().c_str(),
574 ConnectedThroughNetwork(),
575 TicksSinceEpoch<std::chrono::seconds>(m_connected));
576 }
577 m_i2p_sam_session.reset();
578 }
579
580 void CConnman::AddWhitelistPermissionFlags(NetPermissionFlags& flags, std::optional<CNetAddr> addr, const std::vector<NetWhitelistPermissions>& ranges) const {
581 for (const auto& subnet : ranges) {
582 if (addr.has_value() && subnet.m_subnet.Match(addr.value())) {
583 NetPermissions::AddFlag(flags, subnet.m_flags);
584 }
585 }
586 if (NetPermissions::HasFlag(flags, NetPermissionFlags::Implicit)) {
587 NetPermissions::ClearFlag(flags, NetPermissionFlags::Implicit);
588 if (whitelist_forcerelay) NetPermissions::AddFlag(flags, NetPermissionFlags::ForceRelay);
589 if (whitelist_relay) NetPermissions::AddFlag(flags, NetPermissionFlags::Relay);
590 NetPermissions::AddFlag(flags, NetPermissionFlags::Mempool);
591 NetPermissions::AddFlag(flags, NetPermissionFlags::NoBan);
592 }
593 }
594
595 CService CNode::GetAddrLocal() const
596 {
597 AssertLockNotHeld(m_addr_local_mutex);
598 LOCK(m_addr_local_mutex);
599 return m_addr_local;
600 }
601
602 void CNode::SetAddrLocal(const CService& addrLocalIn) {
603 AssertLockNotHeld(m_addr_local_mutex);
604 LOCK(m_addr_local_mutex);
605 if (Assume(!m_addr_local.IsValid())) { // Addr local can only be set once during version msg processing
606 m_addr_local = addrLocalIn;
607 }
608 }
609
610 Network CNode::ConnectedThroughNetwork() const
611 {
612 return m_inbound_onion ? NET_ONION : addr.GetNetClass();
613 }
614
615 bool CNode::IsConnectedThroughPrivacyNet() const
616 {
617 return m_inbound_onion || addr.IsPrivacyNet();
618 }
619
620 #undef X
621 #define X(name) stats.name = name
622 void CNode::CopyStats(CNodeStats& stats)
623 {
624 stats.nodeid = this->GetId();
625 X(addr);
626 X(addrBind);
627 stats.m_network = ConnectedThroughNetwork();
628 X(m_last_send);
629 X(m_last_recv);
630 X(m_last_tx_time);
631 X(m_last_block_time);
632 X(m_connected);
633 X(m_addr_name);
634 X(nVersion);
635 {
636 LOCK(m_subver_mutex);
637 X(cleanSubVer);
638 }
639 stats.fInbound = IsInboundConn();
640 X(m_bip152_highbandwidth_to);
641 X(m_bip152_highbandwidth_from);
642 {
643 LOCK(cs_vSend);
644 X(mapSendBytesPerMsgType);
645 X(nSendBytes);
646 }
647 {
648 LOCK(cs_vRecv);
649 X(mapRecvBytesPerMsgType);
650 X(nRecvBytes);
651 Transport::Info info = m_transport->GetInfo();
652 stats.m_transport_type = info.transport_type;
653 if (info.session_id) stats.m_session_id = HexStr(*info.session_id);
654 }
655 X(m_permission_flags);
656
657 X(m_last_ping_time);
658 X(m_min_ping_time);
659
660 // Leave string empty if addrLocal invalid (not filled in yet)
661 CService addrLocalUnlocked = GetAddrLocal();
662 stats.addrLocal = addrLocalUnlocked.IsValid() ? addrLocalUnlocked.ToStringAddrPort() : "";
663
664 X(m_conn_type);
665 }
666 #undef X
667
668 bool CNode::ReceiveMsgBytes(std::span<const uint8_t> msg_bytes, bool& complete)
669 {
670 complete = false;
671 const auto time{NodeClock::now()};
672 LOCK(cs_vRecv);
673 m_last_recv = time;
674 nRecvBytes += msg_bytes.size();
675 while (msg_bytes.size() > 0) {
676 // absorb network data
677 if (!m_transport->ReceivedBytes(msg_bytes)) {
678 // Serious transport problem, disconnect from the peer.
679 return false;
680 }
681
682 if (m_transport->ReceivedMessageComplete()) {
683 // decompose a transport agnostic CNetMessage from the deserializer
684 bool reject_message{false};
685 CNetMessage msg = m_transport->GetReceivedMessage(time, reject_message);
686 if (reject_message) {
687 // Message deserialization failed. Drop the message but don't disconnect the peer.
688 // store the size of the corrupt message
689 mapRecvBytesPerMsgType.at(NET_MESSAGE_TYPE_OTHER) += msg.m_raw_message_size;
690 continue;
691 }
692
693 // Store received bytes per message type.
694 // To prevent a memory DOS, only allow known message types.
695 auto i = mapRecvBytesPerMsgType.find(msg.m_type);
696 if (i == mapRecvBytesPerMsgType.end()) {
697 i = mapRecvBytesPerMsgType.find(NET_MESSAGE_TYPE_OTHER);
698 }
699 assert(i != mapRecvBytesPerMsgType.end());
700 i->second += msg.m_raw_message_size;
701
702 // push the message to the process queue,
703 vRecvMsg.push_back(std::move(msg));
704
705 complete = true;
706 }
707 }
708
709 return true;
710 }
711
712 std::string CNode::LogPeer() const
713 {
714 auto peer_info{strprintf("peer=%d", GetId())};
715 if (fLogIPs) {
716 return strprintf("%s, peeraddr=%s", peer_info, addr.ToStringAddrPort());
717 } else {
718 return peer_info;
719 }
720 }
721
722 std::string CNode::DisconnectMsg() const
723 {
724 return strprintf("disconnecting %s", LogPeer());
725 }
726
727 V1Transport::V1Transport(const NodeId node_id) noexcept
728 : m_magic_bytes{Params().MessageStart()}, m_node_id{node_id}
729 {
730 LOCK(m_recv_mutex);
731 Reset();
732 }
733
734 Transport::Info V1Transport::GetInfo() const noexcept
735 {
736 return {.transport_type = TransportProtocolType::V1, .session_id = {}};
737 }
738
739 int V1Transport::readHeader(std::span<const uint8_t> msg_bytes)
740 {
741 AssertLockHeld(m_recv_mutex);
742 // copy data to temporary parsing buffer
743 unsigned int nRemaining = CMessageHeader::HEADER_SIZE - nHdrPos;
744 unsigned int nCopy = std::min<unsigned int>(nRemaining, msg_bytes.size());
745
746 memcpy(&hdrbuf[nHdrPos], msg_bytes.data(), nCopy);
747 nHdrPos += nCopy;
748
749 // if header incomplete, exit
750 if (nHdrPos < CMessageHeader::HEADER_SIZE)
751 return nCopy;
752
753 // deserialize to CMessageHeader
754 try {
755 hdrbuf >> hdr;
756 }
757 catch (const std::exception&) {
758 LogDebug(BCLog::NET, "Header error: Unable to deserialize, peer=%d\n", m_node_id);
759 return -1;
760 }
761
762 // Check start string, network magic
763 if (hdr.pchMessageStart != m_magic_bytes) {
764 LogDebug(BCLog::NET, "Header error: Wrong MessageStart %s received, peer=%d\n", HexStr(hdr.pchMessageStart), m_node_id);
765 return -1;
766 }
767
768 // reject messages larger than MAX_SIZE or MAX_PROTOCOL_MESSAGE_LENGTH
769 // NOTE: failing to perform this check previously allowed a malicious peer to make us allocate 32MiB of memory per
770 // connection. See https://bitcoincore.org/en/2024/07/03/disclose_receive_buffer_oom.
771 if (hdr.nMessageSize > MAX_SIZE || hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
772 LogDebug(BCLog::NET, "Header error: Size too large (%s, %u bytes), peer=%d\n", SanitizeString(hdr.GetMessageType()), hdr.nMessageSize, m_node_id);
773 return -1;
774 }
775
776 // switch state to reading message data
777 in_data = true;
778
779 return nCopy;
780 }
781
782 int V1Transport::readData(std::span<const uint8_t> msg_bytes)
783 {
784 AssertLockHeld(m_recv_mutex);
785 unsigned int nRemaining = hdr.nMessageSize - nDataPos;
786 unsigned int nCopy = std::min<unsigned int>(nRemaining, msg_bytes.size());
787
788 if (vRecv.size() < nDataPos + nCopy) {
789 // Allocate up to 256 KiB ahead, but never more than the total message size.
790 vRecv.resize(std::min(hdr.nMessageSize, nDataPos + nCopy + 256 * 1024));
791 }
792
793 hasher.Write(msg_bytes.first(nCopy));
794 memcpy(&vRecv[nDataPos], msg_bytes.data(), nCopy);
795 nDataPos += nCopy;
796
797 return nCopy;
798 }
799
800 const uint256& V1Transport::GetMessageHash() const
801 {
802 AssertLockHeld(m_recv_mutex);
803 assert(CompleteInternal());
804 if (data_hash.IsNull())
805 hasher.Finalize(data_hash);
806 return data_hash;
807 }
808
809 CNetMessage V1Transport::GetReceivedMessage(NodeClock::time_point time, bool& reject_message)
810 {
811 AssertLockNotHeld(m_recv_mutex);
812 // Initialize out parameter
813 reject_message = false;
814 // decompose a single CNetMessage from the TransportDeserializer
815 LOCK(m_recv_mutex);
816 CNetMessage msg(std::move(vRecv));
817
818 // store message type string, time, and sizes
819 msg.m_type = hdr.GetMessageType();
820 msg.m_time = time;
821 msg.m_message_size = hdr.nMessageSize;
822 msg.m_raw_message_size = hdr.nMessageSize + CMessageHeader::HEADER_SIZE;
823
824 uint256 hash = GetMessageHash();
825
826 // We just received a message off the wire, harvest entropy from the time (and the message checksum)
827 RandAddEvent(ReadLE32(hash.begin()));
828
829 // Check checksum and header message type string
830 if (memcmp(hash.begin(), hdr.pchChecksum, CMessageHeader::CHECKSUM_SIZE) != 0) {
831 LogDebug(BCLog::NET, "Header error: Wrong checksum (%s, %u bytes), expected %s was %s, peer=%d\n",
832 SanitizeString(msg.m_type), msg.m_message_size,
833 HexStr(std::span{hash}.first(CMessageHeader::CHECKSUM_SIZE)),
834 HexStr(hdr.pchChecksum),
835 m_node_id);
836 reject_message = true;
837 } else if (!hdr.IsMessageTypeValid()) {
838 LogDebug(BCLog::NET, "Header error: Invalid message type (%s, %u bytes), peer=%d\n",
839 SanitizeString(hdr.GetMessageType()), msg.m_message_size, m_node_id);
840 reject_message = true;
841 }
842
843 // Always reset the network deserializer (prepare for the next message)
844 Reset();
845 return msg;
846 }
847
848 bool V1Transport::SetMessageToSend(CSerializedNetMsg& msg) noexcept
849 {
850 AssertLockNotHeld(m_send_mutex);
851 // Determine whether a new message can be set.
852 LOCK(m_send_mutex);
853 if (m_sending_header || m_bytes_sent < m_message_to_send.data.size()) return false;
854
855 // create dbl-sha256 checksum
856 uint256 hash = Hash(msg.data);
857
858 // create header
859 CMessageHeader hdr(m_magic_bytes, msg.m_type.c_str(), msg.data.size());
860 memcpy(hdr.pchChecksum, hash.begin(), CMessageHeader::CHECKSUM_SIZE);
861
862 // serialize header
863 m_header_to_send.clear();
864 VectorWriter{m_header_to_send, 0, hdr};
865
866 // update state
867 m_message_to_send = std::move(msg);
868 m_sending_header = true;
869 m_bytes_sent = 0;
870 return true;
871 }
872
873 Transport::BytesToSend V1Transport::GetBytesToSend(bool have_next_message) const noexcept
874 {
875 AssertLockNotHeld(m_send_mutex);
876 LOCK(m_send_mutex);
877 if (m_sending_header) {
878 return {std::span{m_header_to_send}.subspan(m_bytes_sent),
879 // We have more to send after the header if the message has payload, or if there
880 // is a next message after that.
881 have_next_message || !m_message_to_send.data.empty(),
882 m_message_to_send.m_type
883 };
884 } else {
885 return {std::span{m_message_to_send.data}.subspan(m_bytes_sent),
886 // We only have more to send after this message's payload if there is another
887 // message.
888 have_next_message,
889 m_message_to_send.m_type
890 };
891 }
892 }
893
894 void V1Transport::MarkBytesSent(size_t bytes_sent) noexcept
895 {
896 AssertLockNotHeld(m_send_mutex);
897 LOCK(m_send_mutex);
898 m_bytes_sent += bytes_sent;
899 if (m_sending_header && m_bytes_sent == m_header_to_send.size()) {
900 // We're done sending a message's header. Switch to sending its data bytes.
901 m_sending_header = false;
902 m_bytes_sent = 0;
903 } else if (!m_sending_header && m_bytes_sent == m_message_to_send.data.size()) {
904 // We're done sending a message's data. Wipe the data vector to reduce memory consumption.
905 ClearShrink(m_message_to_send.data);
906 m_bytes_sent = 0;
907 }
908 }
909
910 size_t V1Transport::GetSendMemoryUsage() const noexcept
911 {
912 AssertLockNotHeld(m_send_mutex);
913 LOCK(m_send_mutex);
914 // Don't count sending-side fields besides m_message_to_send, as they're all small and bounded.
915 return m_message_to_send.GetMemoryUsage();
916 }
917
918 namespace {
919
920 /** List of short messages as defined in BIP324, in order.
921 *
922 * Only message types that are actually implemented in this codebase need to be listed, as other
923 * messages get ignored anyway - whether we know how to decode them or not.
924 */
925 const std::array<std::string, BIP324_SHORTIDS_IMPLEMENTED> V2_MESSAGE_IDS = {
926 "", // 12 bytes follow encoding the message type like in V1
927 NetMsgType::ADDR,
928 NetMsgType::BLOCK,
929 NetMsgType::BLOCKTXN,
930 NetMsgType::CMPCTBLOCK,
931 NetMsgType::FEEFILTER,
932 NetMsgType::FILTERADD,
933 NetMsgType::FILTERCLEAR,
934 NetMsgType::FILTERLOAD,
935 NetMsgType::GETBLOCKS,
936 NetMsgType::GETBLOCKTXN,
937 NetMsgType::GETDATA,
938 NetMsgType::GETHEADERS,
939 NetMsgType::HEADERS,
940 NetMsgType::INV,
941 NetMsgType::MEMPOOL,
942 NetMsgType::MERKLEBLOCK,
943 NetMsgType::NOTFOUND,
944 NetMsgType::PING,
945 NetMsgType::PONG,
946 NetMsgType::SENDCMPCT,
947 NetMsgType::TX,
948 NetMsgType::GETCFILTERS,
949 NetMsgType::CFILTER,
950 NetMsgType::GETCFHEADERS,
951 NetMsgType::CFHEADERS,
952 NetMsgType::GETCFCHECKPT,
953 NetMsgType::CFCHECKPT,
954 NetMsgType::ADDRV2,
955 "", "", "", // Unimplemented message types 29-31
956 "", "", "", "", // Unimplemented message types 32-35
957 "", // Unimplemented message type 36
958 NetMsgType::FEATURE,
959 };
960
961 class V2MessageMap
962 {
963 std::unordered_map<std::string, uint8_t> m_map;
964
965 public:
966 V2MessageMap() noexcept
967 {
968 for (size_t i = 1; i < std::size(V2_MESSAGE_IDS); ++i) {
969 m_map.emplace(V2_MESSAGE_IDS[i], i);
970 }
971 }
972
973 std::optional<uint8_t> operator()(const std::string& message_name) const noexcept
974 {
975 auto it = m_map.find(message_name);
976 if (it == m_map.end()) return std::nullopt;
977 return it->second;
978 }
979 };
980
981 const V2MessageMap V2_MESSAGE_MAP;
982
983 std::vector<uint8_t> GenerateRandomGarbage() noexcept
984 {
985 std::vector<uint8_t> ret;
986 FastRandomContext rng;
987 ret.resize(rng.randrange(V2Transport::MAX_GARBAGE_LEN + 1));
988 rng.fillrand(MakeWritableByteSpan(ret));
989 return ret;
990 }
991
992 } // namespace
993
994 void V2Transport::StartSendingHandshake() noexcept
995 {
996 AssertLockHeld(m_send_mutex);
997 Assume(m_send_state == SendState::AWAITING_KEY);
998 Assume(m_send_buffer.empty());
999 // Initialize the send buffer with ellswift pubkey + provided garbage.
1000 m_send_buffer.resize(EllSwiftPubKey::size() + m_send_garbage.size());
1001 std::copy(std::begin(m_cipher.GetOurPubKey()), std::end(m_cipher.GetOurPubKey()), MakeWritableByteSpan(m_send_buffer).begin());
1002 std::copy(m_send_garbage.begin(), m_send_garbage.end(), m_send_buffer.begin() + EllSwiftPubKey::size());
1003 // We cannot wipe m_send_garbage as it will still be used as AAD later in the handshake.
1004 }
1005
1006 V2Transport::V2Transport(NodeId nodeid, bool initiating, const CKey& key, std::span<const std::byte> ent32, std::vector<uint8_t> garbage) noexcept
1007 : m_cipher{key, ent32},
1008 m_initiating{initiating},
1009 m_nodeid{nodeid},
1010 m_v1_fallback{nodeid},
1011 m_recv_state{initiating ? RecvState::KEY : RecvState::KEY_MAYBE_V1},
1012 m_send_garbage{std::move(garbage)},
1013 m_send_state{initiating ? SendState::AWAITING_KEY : SendState::MAYBE_V1}
1014 {
1015 Assume(m_send_garbage.size() <= MAX_GARBAGE_LEN);
1016 // Start sending immediately if we're the initiator of the connection.
1017 if (initiating) {
1018 LOCK(m_send_mutex);
1019 StartSendingHandshake();
1020 }
1021 }
1022
1023 V2Transport::V2Transport(NodeId nodeid, bool initiating) noexcept
1024 : V2Transport{nodeid, initiating, GenerateRandomKey(),
1025 MakeByteSpan(GetRandHash()), GenerateRandomGarbage()} {}
1026
1027 void V2Transport::SetReceiveState(RecvState recv_state) noexcept
1028 {
1029 AssertLockHeld(m_recv_mutex);
1030 // Enforce allowed state transitions.
1031 switch (m_recv_state) {
1032 case RecvState::KEY_MAYBE_V1:
1033 Assume(recv_state == RecvState::KEY || recv_state == RecvState::V1);
1034 break;
1035 case RecvState::KEY:
1036 Assume(recv_state == RecvState::GARB_GARBTERM);
1037 break;
1038 case RecvState::GARB_GARBTERM:
1039 Assume(recv_state == RecvState::VERSION);
1040 break;
1041 case RecvState::VERSION:
1042 Assume(recv_state == RecvState::APP);
1043 break;
1044 case RecvState::APP:
1045 Assume(recv_state == RecvState::APP_READY);
1046 break;
1047 case RecvState::APP_READY:
1048 Assume(recv_state == RecvState::APP);
1049 break;
1050 case RecvState::V1:
1051 Assume(false); // V1 state cannot be left
1052 break;
1053 }
1054 // Change state.
1055 m_recv_state = recv_state;
1056 }
1057
1058 void V2Transport::SetSendState(SendState send_state) noexcept
1059 {
1060 AssertLockHeld(m_send_mutex);
1061 // Enforce allowed state transitions.
1062 switch (m_send_state) {
1063 case SendState::MAYBE_V1:
1064 Assume(send_state == SendState::V1 || send_state == SendState::AWAITING_KEY);
1065 break;
1066 case SendState::AWAITING_KEY:
1067 Assume(send_state == SendState::READY);
1068 break;
1069 case SendState::READY:
1070 case SendState::V1:
1071 Assume(false); // Final states
1072 break;
1073 }
1074 // Change state.
1075 m_send_state = send_state;
1076 }
1077
1078 bool V2Transport::ReceivedMessageComplete() const noexcept
1079 {
1080 AssertLockNotHeld(m_recv_mutex);
1081 LOCK(m_recv_mutex);
1082 if (m_recv_state == RecvState::V1) return m_v1_fallback.ReceivedMessageComplete();
1083
1084 return m_recv_state == RecvState::APP_READY;
1085 }
1086
1087 void V2Transport::ProcessReceivedMaybeV1Bytes() noexcept
1088 {
1089 AssertLockHeld(m_recv_mutex);
1090 AssertLockNotHeld(m_send_mutex);
1091 Assume(m_recv_state == RecvState::KEY_MAYBE_V1);
1092 // We still have to determine if this is a v1 or v2 connection. The bytes being received could
1093 // be the beginning of either a v1 packet (network magic + "version\x00\x00\x00\x00\x00"), or
1094 // of a v2 public key. BIP324 specifies that a mismatch with this 16-byte string should trigger
1095 // sending of the key.
1096 std::array<uint8_t, V1_PREFIX_LEN> v1_prefix = {0, 0, 0, 0, 'v', 'e', 'r', 's', 'i', 'o', 'n', 0, 0, 0, 0, 0};
1097 std::copy(std::begin(Params().MessageStart()), std::end(Params().MessageStart()), v1_prefix.begin());
1098 Assume(m_recv_buffer.size() <= v1_prefix.size());
1099 if (!std::equal(m_recv_buffer.begin(), m_recv_buffer.end(), v1_prefix.begin())) {
1100 // Mismatch with v1 prefix, so we can assume a v2 connection.
1101 SetReceiveState(RecvState::KEY); // Convert to KEY state, leaving received bytes around.
1102 // Transition the sender to AWAITING_KEY state and start sending.
1103 LOCK(m_send_mutex);
1104 SetSendState(SendState::AWAITING_KEY);
1105 StartSendingHandshake();
1106 } else if (m_recv_buffer.size() == v1_prefix.size()) {
1107 // Full match with the v1 prefix, so fall back to v1 behavior.
1108 LOCK(m_send_mutex);
1109 std::span<const uint8_t> feedback{m_recv_buffer};
1110 // Feed already received bytes to v1 transport. It should always accept these, because it's
1111 // less than the size of a v1 header, and these are the first bytes fed to m_v1_fallback.
1112 bool ret = m_v1_fallback.ReceivedBytes(feedback);
1113 Assume(feedback.empty());
1114 Assume(ret);
1115 SetReceiveState(RecvState::V1);
1116 SetSendState(SendState::V1);
1117 // Reset v2 transport buffers to save memory.
1118 ClearShrink(m_recv_buffer);
1119 ClearShrink(m_send_buffer);
1120 } else {
1121 // We have not received enough to distinguish v1 from v2 yet. Wait until more bytes come.
1122 }
1123 }
1124
1125 bool V2Transport::ProcessReceivedKeyBytes() noexcept
1126 {
1127 AssertLockHeld(m_recv_mutex);
1128 AssertLockNotHeld(m_send_mutex);
1129 Assume(m_recv_state == RecvState::KEY);
1130 Assume(m_recv_buffer.size() <= EllSwiftPubKey::size());
1131
1132 // As a special exception, if bytes 4-16 of the key on a responder connection match the
1133 // corresponding bytes of a V1 version message, but bytes 0-4 don't match the network magic
1134 // (if they did, we'd have switched to V1 state already), assume this is a peer from
1135 // another network, and disconnect them. They will almost certainly disconnect us too when
1136 // they receive our uniformly random key and garbage, but detecting this case specially
1137 // means we can log it.
1138 static constexpr std::array<uint8_t, 12> MATCH = {'v', 'e', 'r', 's', 'i', 'o', 'n', 0, 0, 0, 0, 0};
1139 static constexpr size_t OFFSET = std::tuple_size_v<MessageStartChars>;
1140 if (!m_initiating && m_recv_buffer.size() >= OFFSET + MATCH.size()) {
1141 if (std::equal(MATCH.begin(), MATCH.end(), m_recv_buffer.begin() + OFFSET)) {
1142 LogDebug(BCLog::NET, "V2 transport error: V1 peer with wrong MessageStart %s\n",
1143 HexStr(std::span(m_recv_buffer).first(OFFSET)));
1144 return false;
1145 }
1146 }
1147
1148 if (m_recv_buffer.size() == EllSwiftPubKey::size()) {
1149 // Other side's key has been fully received, and can now be Diffie-Hellman combined with
1150 // our key to initialize the encryption ciphers.
1151
1152 // Initialize the ciphers.
1153 EllSwiftPubKey ellswift(MakeByteSpan(m_recv_buffer));
1154 LOCK(m_send_mutex);
1155 m_cipher.Initialize(ellswift, m_initiating);
1156
1157 // Switch receiver state to GARB_GARBTERM.
1158 SetReceiveState(RecvState::GARB_GARBTERM);
1159 m_recv_buffer.clear();
1160
1161 // Switch sender state to READY.
1162 SetSendState(SendState::READY);
1163
1164 // Append the garbage terminator to the send buffer.
1165 m_send_buffer.resize(m_send_buffer.size() + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
1166 std::copy(m_cipher.GetSendGarbageTerminator().begin(),
1167 m_cipher.GetSendGarbageTerminator().end(),
1168 MakeWritableByteSpan(m_send_buffer).last(BIP324Cipher::GARBAGE_TERMINATOR_LEN).begin());
1169
1170 // Construct version packet in the send buffer, with the sent garbage data as AAD.
1171 m_send_buffer.resize(m_send_buffer.size() + BIP324Cipher::EXPANSION + VERSION_CONTENTS.size());
1172 m_cipher.Encrypt(
1173 /*contents=*/VERSION_CONTENTS,
1174 /*aad=*/MakeByteSpan(m_send_garbage),
1175 /*ignore=*/false,
1176 /*output=*/MakeWritableByteSpan(m_send_buffer).last(BIP324Cipher::EXPANSION + VERSION_CONTENTS.size()));
1177 // We no longer need the garbage.
1178 ClearShrink(m_send_garbage);
1179 } else {
1180 // We still have to receive more key bytes.
1181 }
1182 return true;
1183 }
1184
1185 bool V2Transport::ProcessReceivedGarbageBytes() noexcept
1186 {
1187 AssertLockHeld(m_recv_mutex);
1188 Assume(m_recv_state == RecvState::GARB_GARBTERM);
1189 Assume(m_recv_buffer.size() <= MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
1190 if (m_recv_buffer.size() >= BIP324Cipher::GARBAGE_TERMINATOR_LEN) {
1191 if (std::ranges::equal(MakeByteSpan(m_recv_buffer).last(BIP324Cipher::GARBAGE_TERMINATOR_LEN), m_cipher.GetReceiveGarbageTerminator())) {
1192 // Garbage terminator received. Store garbage to authenticate it as AAD later.
1193 m_recv_aad = std::move(m_recv_buffer);
1194 m_recv_aad.resize(m_recv_aad.size() - BIP324Cipher::GARBAGE_TERMINATOR_LEN);
1195 m_recv_buffer.clear();
1196 SetReceiveState(RecvState::VERSION);
1197 } else if (m_recv_buffer.size() == MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN) {
1198 // We've reached the maximum length for garbage + garbage terminator, and the
1199 // terminator still does not match. Abort.
1200 LogDebug(BCLog::NET, "V2 transport error: missing garbage terminator, peer=%d\n", m_nodeid);
1201 return false;
1202 } else {
1203 // We still need to receive more garbage and/or garbage terminator bytes.
1204 }
1205 } else {
1206 // We have less than GARBAGE_TERMINATOR_LEN (16) bytes, so we certainly need to receive
1207 // more first.
1208 }
1209 return true;
1210 }
1211
1212 bool V2Transport::ProcessReceivedPacketBytes() noexcept
1213 {
1214 AssertLockHeld(m_recv_mutex);
1215 Assume(m_recv_state == RecvState::VERSION || m_recv_state == RecvState::APP);
1216
1217 // The maximum permitted contents length for a packet, consisting of:
1218 // - 0x00 byte: indicating long message type encoding
1219 // - 12 bytes of message type
1220 // - payload
1221 static constexpr size_t MAX_CONTENTS_LEN =
1222 1 + CMessageHeader::MESSAGE_TYPE_SIZE +
1223 std::min<size_t>(MAX_SIZE, MAX_PROTOCOL_MESSAGE_LENGTH);
1224
1225 if (m_recv_buffer.size() == BIP324Cipher::LENGTH_LEN) {
1226 // Length descriptor received.
1227 m_recv_len = m_cipher.DecryptLength(MakeByteSpan(m_recv_buffer));
1228 if (m_recv_len > MAX_CONTENTS_LEN) {
1229 LogDebug(BCLog::NET, "V2 transport error: packet too large (%u bytes), peer=%d\n", m_recv_len, m_nodeid);
1230 return false;
1231 }
1232 } else if (m_recv_buffer.size() > BIP324Cipher::LENGTH_LEN && m_recv_buffer.size() == m_recv_len + BIP324Cipher::EXPANSION) {
1233 // Ciphertext received, decrypt it into m_recv_decode_buffer.
1234 // Note that it is impossible to reach this branch without hitting the branch above first,
1235 // as GetMaxBytesToProcess only allows up to LENGTH_LEN into the buffer before that point.
1236 m_recv_decode_buffer.resize(m_recv_len);
1237 bool ignore{false};
1238 bool ret = m_cipher.Decrypt(
1239 /*input=*/MakeByteSpan(m_recv_buffer).subspan(BIP324Cipher::LENGTH_LEN),
1240 /*aad=*/MakeByteSpan(m_recv_aad),
1241 /*ignore=*/ignore,
1242 /*contents=*/MakeWritableByteSpan(m_recv_decode_buffer));
1243 if (!ret) {
1244 LogDebug(BCLog::NET, "V2 transport error: packet decryption failure (%u bytes), peer=%d\n", m_recv_len, m_nodeid);
1245 return false;
1246 }
1247 // We have decrypted a valid packet with the AAD we expected, so clear the expected AAD.
1248 ClearShrink(m_recv_aad);
1249 // Feed the last 4 bytes of the Poly1305 authentication tag (and its timing) into our RNG.
1250 RandAddEvent(ReadLE32(m_recv_buffer.data() + m_recv_buffer.size() - 4));
1251
1252 // At this point we have a valid packet decrypted into m_recv_decode_buffer. If it's not a
1253 // decoy, which we simply ignore, use the current state to decide what to do with it.
1254 if (!ignore) {
1255 switch (m_recv_state) {
1256 case RecvState::VERSION:
1257 // Version message received; transition to application phase. The contents is
1258 // ignored, but can be used for future extensions.
1259 SetReceiveState(RecvState::APP);
1260 break;
1261 case RecvState::APP:
1262 // Application message decrypted correctly. It can be extracted using GetMessage().
1263 SetReceiveState(RecvState::APP_READY);
1264 break;
1265 default:
1266 // Any other state is invalid (this function should not have been called).
1267 Assume(false);
1268 }
1269 }
1270 // Wipe the receive buffer where the next packet will be received into.
1271 ClearShrink(m_recv_buffer);
1272 // In all but APP_READY state, we can wipe the decoded contents.
1273 if (m_recv_state != RecvState::APP_READY) ClearShrink(m_recv_decode_buffer);
1274 } else {
1275 // We either have less than 3 bytes, so we don't know the packet's length yet, or more
1276 // than 3 bytes but less than the packet's full ciphertext. Wait until those arrive.
1277 }
1278 return true;
1279 }
1280
1281 size_t V2Transport::GetMaxBytesToProcess() noexcept
1282 {
1283 AssertLockHeld(m_recv_mutex);
1284 switch (m_recv_state) {
1285 case RecvState::KEY_MAYBE_V1:
1286 // During the KEY_MAYBE_V1 state we do not allow more than the length of v1 prefix into the
1287 // receive buffer.
1288 Assume(m_recv_buffer.size() <= V1_PREFIX_LEN);
1289 // As long as we're not sure if this is a v1 or v2 connection, don't receive more than what
1290 // is strictly necessary to distinguish the two (16 bytes). If we permitted more than
1291 // the v1 header size (24 bytes), we may not be able to feed the already-received bytes
1292 // back into the m_v1_fallback V1 transport.
1293 return V1_PREFIX_LEN - m_recv_buffer.size();
1294 case RecvState::KEY:
1295 // During the KEY state, we only allow the 64-byte key into the receive buffer.
1296 Assume(m_recv_buffer.size() <= EllSwiftPubKey::size());
1297 // As long as we have not received the other side's public key, don't receive more than
1298 // that (64 bytes), as garbage follows, and locating the garbage terminator requires the
1299 // key exchange first.
1300 return EllSwiftPubKey::size() - m_recv_buffer.size();
1301 case RecvState::GARB_GARBTERM:
1302 // Process garbage bytes one by one (because terminator may appear anywhere).
1303 return 1;
1304 case RecvState::VERSION:
1305 case RecvState::APP:
1306 // These three states all involve decoding a packet. Process the length descriptor first,
1307 // so that we know where the current packet ends (and we don't process bytes from the next
1308 // packet or decoy yet). Then, process the ciphertext bytes of the current packet.
1309 if (m_recv_buffer.size() < BIP324Cipher::LENGTH_LEN) {
1310 return BIP324Cipher::LENGTH_LEN - m_recv_buffer.size();
1311 } else {
1312 // Note that BIP324Cipher::EXPANSION is the total difference between contents size
1313 // and encoded packet size, which includes the 3 bytes due to the packet length.
1314 // When transitioning from receiving the packet length to receiving its ciphertext,
1315 // the encrypted packet length is left in the receive buffer.
1316 return BIP324Cipher::EXPANSION + m_recv_len - m_recv_buffer.size();
1317 }
1318 case RecvState::APP_READY:
1319 // No bytes can be processed until GetMessage() is called.
1320 return 0;
1321 case RecvState::V1:
1322 // Not allowed (must be dealt with by the caller).
1323 Assume(false);
1324 return 0;
1325 }
1326 Assume(false); // unreachable
1327 return 0;
1328 }
1329
1330 bool V2Transport::ReceivedBytes(std::span<const uint8_t>& msg_bytes) noexcept
1331 {
1332 AssertLockNotHeld(m_recv_mutex);
1333 /** How many bytes to allocate in the receive buffer at most above what is received so far. */
1334 static constexpr size_t MAX_RESERVE_AHEAD = 256 * 1024;
1335
1336 LOCK(m_recv_mutex);
1337 if (m_recv_state == RecvState::V1) return m_v1_fallback.ReceivedBytes(msg_bytes);
1338
1339 // Process the provided bytes in msg_bytes in a loop. In each iteration a nonzero number of
1340 // bytes (decided by GetMaxBytesToProcess) are taken from the beginning om msg_bytes, and
1341 // appended to m_recv_buffer. Then, depending on the receiver state, one of the
1342 // ProcessReceived*Bytes functions is called to process the bytes in that buffer.
1343 while (!msg_bytes.empty()) {
1344 // Decide how many bytes to copy from msg_bytes to m_recv_buffer.
1345 size_t max_read = GetMaxBytesToProcess();
1346
1347 // Reserve space in the buffer if there is not enough.
1348 if (m_recv_buffer.size() + std::min(msg_bytes.size(), max_read) > m_recv_buffer.capacity()) {
1349 switch (m_recv_state) {
1350 case RecvState::KEY_MAYBE_V1:
1351 case RecvState::KEY:
1352 case RecvState::GARB_GARBTERM:
1353 // During the initial states (key/garbage), allocate once to fit the maximum (4111
1354 // bytes).
1355 m_recv_buffer.reserve(MAX_GARBAGE_LEN + BIP324Cipher::GARBAGE_TERMINATOR_LEN);
1356 break;
1357 case RecvState::VERSION:
1358 case RecvState::APP: {
1359 // During states where a packet is being received, as much as is expected but never
1360 // more than MAX_RESERVE_AHEAD bytes in addition to what is received so far.
1361 // This means attackers that want to cause us to waste allocated memory are limited
1362 // to MAX_RESERVE_AHEAD above the largest allowed message contents size, and to
1363 // MAX_RESERVE_AHEAD more than they've actually sent us.
1364 size_t alloc_add = std::min(max_read, msg_bytes.size() + MAX_RESERVE_AHEAD);
1365 m_recv_buffer.reserve(m_recv_buffer.size() + alloc_add);
1366 break;
1367 }
1368 case RecvState::APP_READY:
1369 // The buffer is empty in this state.
1370 Assume(m_recv_buffer.empty());
1371 break;
1372 case RecvState::V1:
1373 // Should have bailed out above.
1374 Assume(false);
1375 break;
1376 }
1377 }
1378
1379 // Can't read more than provided input.
1380 max_read = std::min(msg_bytes.size(), max_read);
1381 // Copy data to buffer.
1382 m_recv_buffer.insert(m_recv_buffer.end(), UCharCast(msg_bytes.data()), UCharCast(msg_bytes.data() + max_read));
1383 msg_bytes = msg_bytes.subspan(max_read);
1384
1385 // Process data in the buffer.
1386 switch (m_recv_state) {
1387 case RecvState::KEY_MAYBE_V1:
1388 ProcessReceivedMaybeV1Bytes();
1389 if (m_recv_state == RecvState::V1) return true;
1390 break;
1391
1392 case RecvState::KEY:
1393 if (!ProcessReceivedKeyBytes()) return false;
1394 break;
1395
1396 case RecvState::GARB_GARBTERM:
1397 if (!ProcessReceivedGarbageBytes()) return false;
1398 break;
1399
1400 case RecvState::VERSION:
1401 case RecvState::APP:
1402 if (!ProcessReceivedPacketBytes()) return false;
1403 break;
1404
1405 case RecvState::APP_READY:
1406 return true;
1407
1408 case RecvState::V1:
1409 // We should have bailed out before.
1410 Assume(false);
1411 break;
1412 }
1413 // Make sure we have made progress before continuing.
1414 Assume(max_read > 0);
1415 }
1416
1417 return true;
1418 }
1419
1420 std::optional<std::string> V2Transport::GetMessageType(std::span<const uint8_t>& contents) noexcept
1421 {
1422 if (contents.size() == 0) return std::nullopt; // Empty contents
1423 uint8_t first_byte = contents[0];
1424 contents = contents.subspan(1); // Strip first byte.
1425
1426 if (first_byte != 0) {
1427 // Short (1 byte) encoding.
1428 if (first_byte < std::size(V2_MESSAGE_IDS)) {
1429 // Valid short message id.
1430 return V2_MESSAGE_IDS[first_byte];
1431 } else {
1432 // Unknown short message id.
1433 return std::nullopt;
1434 }
1435 }
1436
1437 if (contents.size() < CMessageHeader::MESSAGE_TYPE_SIZE) {
1438 return std::nullopt; // Long encoding needs 12 message type bytes.
1439 }
1440
1441 size_t msg_type_len{0};
1442 while (msg_type_len < CMessageHeader::MESSAGE_TYPE_SIZE && contents[msg_type_len] != 0) {
1443 // Verify that message type bytes before the first 0x00 are in range.
1444 if (contents[msg_type_len] < ' ' || contents[msg_type_len] > 0x7F) {
1445 return {};
1446 }
1447 ++msg_type_len;
1448 }
1449 std::string ret{reinterpret_cast<const char*>(contents.data()), msg_type_len};
1450 while (msg_type_len < CMessageHeader::MESSAGE_TYPE_SIZE) {
1451 // Verify that message type bytes after the first 0x00 are also 0x00.
1452 if (contents[msg_type_len] != 0) return {};
1453 ++msg_type_len;
1454 }
1455 // Strip message type bytes of contents.
1456 contents = contents.subspan(CMessageHeader::MESSAGE_TYPE_SIZE);
1457 return ret;
1458 }
1459
1460 CNetMessage V2Transport::GetReceivedMessage(NodeClock::time_point time, bool& reject_message) noexcept
1461 {
1462 AssertLockNotHeld(m_recv_mutex);
1463 LOCK(m_recv_mutex);
1464 if (m_recv_state == RecvState::V1) return m_v1_fallback.GetReceivedMessage(time, reject_message);
1465
1466 Assume(m_recv_state == RecvState::APP_READY);
1467 std::span<const uint8_t> contents{m_recv_decode_buffer};
1468 auto msg_type = GetMessageType(contents);
1469 CNetMessage msg{DataStream{}};
1470 // Note that BIP324Cipher::EXPANSION also includes the length descriptor size.
1471 msg.m_raw_message_size = m_recv_decode_buffer.size() + BIP324Cipher::EXPANSION;
1472 if (msg_type) {
1473 reject_message = false;
1474 msg.m_type = std::move(*msg_type);
1475 msg.m_time = time;
1476 msg.m_message_size = contents.size();
1477 msg.m_recv.resize(contents.size());
1478 std::copy(contents.begin(), contents.end(), UCharCast(msg.m_recv.data()));
1479 } else {
1480 LogDebug(BCLog::NET, "V2 transport error: invalid message type (%u bytes contents), peer=%d\n", m_recv_decode_buffer.size(), m_nodeid);
1481 reject_message = true;
1482 }
1483 ClearShrink(m_recv_decode_buffer);
1484 SetReceiveState(RecvState::APP);
1485
1486 return msg;
1487 }
1488
1489 bool V2Transport::SetMessageToSend(CSerializedNetMsg& msg) noexcept
1490 {
1491 AssertLockNotHeld(m_send_mutex);
1492 LOCK(m_send_mutex);
1493 if (m_send_state == SendState::V1) return m_v1_fallback.SetMessageToSend(msg);
1494 // We only allow adding a new message to be sent when in the READY state (so the packet cipher
1495 // is available) and the send buffer is empty. This limits the number of messages in the send
1496 // buffer to just one, and leaves the responsibility for queueing them up to the caller.
1497 if (!(m_send_state == SendState::READY && m_send_buffer.empty())) return false;
1498 // Construct contents (encoding message type + payload).
1499 std::vector<uint8_t> contents;
1500 auto short_message_id = V2_MESSAGE_MAP(msg.m_type);
1501 if (short_message_id) {
1502 contents.resize(1 + msg.data.size());
1503 contents[0] = *short_message_id;
1504 std::copy(msg.data.begin(), msg.data.end(), contents.begin() + 1);
1505 } else {
1506 // Initialize with zeroes, and then write the message type string starting at offset 1.
1507 // This means contents[0] and the unused positions in contents[1..13] remain 0x00.
1508 contents.resize(1 + CMessageHeader::MESSAGE_TYPE_SIZE + msg.data.size(), 0);
1509 std::copy(msg.m_type.begin(), msg.m_type.end(), contents.data() + 1);
1510 std::copy(msg.data.begin(), msg.data.end(), contents.begin() + 1 + CMessageHeader::MESSAGE_TYPE_SIZE);
1511 }
1512 // Construct ciphertext in send buffer.
1513 m_send_buffer.resize(contents.size() + BIP324Cipher::EXPANSION);
1514 m_cipher.Encrypt(MakeByteSpan(contents), {}, false, MakeWritableByteSpan(m_send_buffer));
1515 m_send_type = msg.m_type;
1516 // Release memory
1517 ClearShrink(msg.data);
1518 return true;
1519 }
1520
1521 Transport::BytesToSend V2Transport::GetBytesToSend(bool have_next_message) const noexcept
1522 {
1523 AssertLockNotHeld(m_send_mutex);
1524 LOCK(m_send_mutex);
1525 if (m_send_state == SendState::V1) return m_v1_fallback.GetBytesToSend(have_next_message);
1526
1527 if (m_send_state == SendState::MAYBE_V1) Assume(m_send_buffer.empty());
1528 Assume(m_send_pos <= m_send_buffer.size());
1529 return {
1530 std::span{m_send_buffer}.subspan(m_send_pos),
1531 // We only have more to send after the current m_send_buffer if there is a (next)
1532 // message to be sent, and we're capable of sending packets. */
1533 have_next_message && m_send_state == SendState::READY,
1534 m_send_type
1535 };
1536 }
1537
1538 void V2Transport::MarkBytesSent(size_t bytes_sent) noexcept
1539 {
1540 AssertLockNotHeld(m_send_mutex);
1541 LOCK(m_send_mutex);
1542 if (m_send_state == SendState::V1) return m_v1_fallback.MarkBytesSent(bytes_sent);
1543
1544 if (m_send_state == SendState::AWAITING_KEY && m_send_pos == 0 && bytes_sent > 0) {
1545 LogDebug(BCLog::NET, "start sending v2 handshake to peer=%d\n", m_nodeid);
1546 }
1547
1548 m_send_pos += bytes_sent;
1549 Assume(m_send_pos <= m_send_buffer.size());
1550 if (m_send_pos >= CMessageHeader::HEADER_SIZE) {
1551 m_sent_v1_header_worth = true;
1552 }
1553 // Wipe the buffer when everything is sent.
1554 if (m_send_pos == m_send_buffer.size()) {
1555 m_send_pos = 0;
1556 ClearShrink(m_send_buffer);
1557 }
1558 }
1559
1560 bool V2Transport::ShouldReconnectV1() const noexcept
1561 {
1562 AssertLockNotHeld(m_send_mutex);
1563 AssertLockNotHeld(m_recv_mutex);
1564 // Only outgoing connections need reconnection.
1565 if (!m_initiating) return false;
1566
1567 LOCK(m_recv_mutex);
1568 // We only reconnect in the very first state and when the receive buffer is empty. Together
1569 // these conditions imply nothing has been received so far.
1570 if (m_recv_state != RecvState::KEY) return false;
1571 if (!m_recv_buffer.empty()) return false;
1572 // Check if we've sent enough for the other side to disconnect us (if it was V1).
1573 LOCK(m_send_mutex);
1574 return m_sent_v1_header_worth;
1575 }
1576
1577 size_t V2Transport::GetSendMemoryUsage() const noexcept
1578 {
1579 AssertLockNotHeld(m_send_mutex);
1580 LOCK(m_send_mutex);
1581 if (m_send_state == SendState::V1) return m_v1_fallback.GetSendMemoryUsage();
1582
1583 return sizeof(m_send_buffer) + memusage::DynamicUsage(m_send_buffer);
1584 }
1585
1586 Transport::Info V2Transport::GetInfo() const noexcept
1587 {
1588 AssertLockNotHeld(m_recv_mutex);
1589 LOCK(m_recv_mutex);
1590 if (m_recv_state == RecvState::V1) return m_v1_fallback.GetInfo();
1591
1592 Transport::Info info;
1593
1594 // Do not report v2 and session ID until the version packet has been received
1595 // and verified (confirming that the other side very likely has the same keys as us).
1596 if (m_recv_state != RecvState::KEY_MAYBE_V1 && m_recv_state != RecvState::KEY &&
1597 m_recv_state != RecvState::GARB_GARBTERM && m_recv_state != RecvState::VERSION) {
1598 info.transport_type = TransportProtocolType::V2;
1599 info.session_id = uint256(MakeUCharSpan(m_cipher.GetSessionID()));
1600 } else {
1601 info.transport_type = TransportProtocolType::DETECTING;
1602 }
1603
1604 return info;
1605 }
1606
1607 std::pair<size_t, bool> CConnman::SocketSendData(CNode& node) const
1608 {
1609 auto it = node.vSendMsg.begin();
1610 size_t nSentSize = 0;
1611 bool data_left{false}; //!< second return value (whether unsent data remains)
1612 std::optional<bool> expected_more;
1613
1614 while (true) {
1615 if (it != node.vSendMsg.end()) {
1616 // If possible, move one message from the send queue to the transport. This fails when
1617 // there is an existing message still being sent, or (for v2 transports) when the
1618 // handshake has not yet completed.
1619 size_t memusage = it->GetMemoryUsage();
1620 if (node.m_transport->SetMessageToSend(*it)) {
1621 // Update memory usage of send buffer (as *it will be deleted).
1622 node.m_send_memusage -= memusage;
1623 ++it;
1624 }
1625 }
1626 const auto& [data, more, msg_type] = node.m_transport->GetBytesToSend(it != node.vSendMsg.end());
1627 // We rely on the 'more' value returned by GetBytesToSend to correctly predict whether more
1628 // bytes are still to be sent, to correctly set the MSG_MORE flag. As a sanity check,
1629 // verify that the previously returned 'more' was correct.
1630 if (expected_more.has_value()) Assume(!data.empty() == *expected_more);
1631 expected_more = more;
1632 data_left = !data.empty(); // will be overwritten on next loop if all of data gets sent
1633 int nBytes = 0;
1634 if (!data.empty()) {
1635 LOCK(node.m_sock_mutex);
1636 // There is no socket in case we've already disconnected, or in test cases without
1637 // real connections. In these cases, we bail out immediately and just leave things
1638 // in the send queue and transport.
1639 if (!node.m_sock) {
1640 break;
1641 }
1642 int flags = MSG_NOSIGNAL | MSG_DONTWAIT;
1643 #ifdef MSG_MORE
1644 if (more) {
1645 flags |= MSG_MORE;
1646 }
1647 #endif
1648 nBytes = node.m_sock->Send(data.data(), data.size(), flags);
1649 }
1650 if (nBytes > 0) {
1651 node.m_last_send = NodeClock::now();
1652 node.nSendBytes += nBytes;
1653 // Notify transport that bytes have been processed.
1654 node.m_transport->MarkBytesSent(nBytes);
1655 // Update statistics per message type.
1656 if (!msg_type.empty()) { // don't report v2 handshake bytes for now
1657 node.AccountForSentBytes(msg_type, nBytes);
1658 }
1659 nSentSize += nBytes;
1660 if ((size_t)nBytes != data.size()) {
1661 // could not send full message; stop sending more
1662 break;
1663 }
1664 } else {
1665 if (nBytes < 0) {
1666 // error
1667 int nErr = WSAGetLastError();
1668 if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS) {
1669 LogDebug(BCLog::NET, "socket send error, %s: %s", node.DisconnectMsg(), NetworkErrorString(nErr));
1670 node.CloseSocketDisconnect();
1671 }
1672 }
1673 break;
1674 }
1675 }
1676
1677 node.fPauseSend = node.m_send_memusage + node.m_transport->GetSendMemoryUsage() > nSendBufferMaxSize;
1678
1679 if (it == node.vSendMsg.end()) {
1680 assert(node.m_send_memusage == 0);
1681 }
1682 node.vSendMsg.erase(node.vSendMsg.begin(), it);
1683 return {nSentSize, data_left};
1684 }
1685
1686 /** Try to find a connection to evict when the node is full.
1687 * Extreme care must be taken to avoid opening the node to attacker
1688 * triggered network partitioning.
1689 * The strategy used here is to protect a small number of peers
1690 * for each of several distinct characteristics which are difficult
1691 * to forge. In order to partition a node the attacker must be
1692 * simultaneously better at all of them than honest peers.
1693 */
1694 bool CConnman::AttemptToEvictConnection()
1695 {
1696 AssertLockNotHeld(m_nodes_mutex);
1697
1698 std::vector<NodeEvictionCandidate> vEvictionCandidates;
1699 {
1700
1701 LOCK(m_nodes_mutex);
1702 for (const CNode* node : m_nodes) {
1703 if (node->fDisconnect)
1704 continue;
1705 NodeEvictionCandidate candidate{
1706 .id = node->GetId(),
1707 .m_connected = node->m_connected,
1708 .m_min_ping_time = node->m_min_ping_time,
1709 .m_last_block_time = node->m_last_block_time,
1710 .m_last_tx_time = node->m_last_tx_time,
1711 .fRelevantServices = node->m_has_all_wanted_services,
1712 .m_relay_txs = node->m_relays_txs.load(),
1713 .fBloomFilter = node->m_bloom_filter_loaded.load(),
1714 .nKeyedNetGroup = node->nKeyedNetGroup,
1715 .prefer_evict = node->m_prefer_evict,
1716 .m_is_local = node->addr.IsLocal(),
1717 .m_network = node->ConnectedThroughNetwork(),
1718 .m_noban = node->HasPermission(NetPermissionFlags::NoBan),
1719 .m_conn_type = node->m_conn_type,
1720 };
1721 vEvictionCandidates.push_back(candidate);
1722 }
1723 }
1724 const std::optional<NodeId> node_id_to_evict = SelectNodeToEvict(std::move(vEvictionCandidates));
1725 if (!node_id_to_evict) {
1726 return false;
1727 }
1728 LOCK(m_nodes_mutex);
1729 for (CNode* pnode : m_nodes) {
1730 if (pnode->GetId() == *node_id_to_evict) {
1731 LogDebug(BCLog::NET, "selected %s connection for eviction, %s", pnode->ConnectionTypeAsString(), pnode->DisconnectMsg());
1732 TRACEPOINT(net, evicted_inbound_connection,
1733 pnode->GetId(),
1734 pnode->m_addr_name.c_str(),
1735 pnode->ConnectionTypeAsString().c_str(),
1736 pnode->ConnectedThroughNetwork(),
1737 TicksSinceEpoch<std::chrono::seconds>(pnode->m_connected));
1738 pnode->fDisconnect = true;
1739 return true;
1740 }
1741 }
1742 return false;
1743 }
1744
1745 void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
1746 AssertLockNotHeld(m_nodes_mutex);
1747
1748 struct sockaddr_storage sockaddr;
1749 socklen_t len = sizeof(sockaddr);
1750 auto sock = hListenSocket.sock->Accept((struct sockaddr*)&sockaddr, &len);
1751
1752 if (!sock) {
1753 const int nErr = WSAGetLastError();
1754 if (nErr != WSAEWOULDBLOCK) {
1755 LogInfo("socket error accept failed: %s\n", NetworkErrorString(nErr));
1756 }
1757 return;
1758 }
1759
1760 CService addr;
1761 if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr, len)) {
1762 LogWarning("Unknown socket family\n");
1763 } else {
1764 addr = MaybeFlipIPv6toCJDNS(addr);
1765 }
1766
1767 const CService addr_bind{MaybeFlipIPv6toCJDNS(GetBindAddress(*sock))};
1768
1769 NetPermissionFlags permission_flags = NetPermissionFlags::None;
1770 hListenSocket.AddSocketPermissionFlags(permission_flags);
1771
1772 CreateNodeFromAcceptedSocket(std::move(sock), permission_flags, addr_bind, addr);
1773 }
1774
1775 void CConnman::CreateNodeFromAcceptedSocket(std::unique_ptr<Sock>&& sock,
1776 NetPermissionFlags permission_flags,
1777 const CService& addr_bind,
1778 const CService& addr)
1779 {
1780 AssertLockNotHeld(m_nodes_mutex);
1781
1782 int nInbound = 0;
1783
1784 const bool inbound_onion = std::find(m_onion_binds.begin(), m_onion_binds.end(), addr_bind) != m_onion_binds.end();
1785
1786 // Tor inbound connections do not reveal the peer's actual network address.
1787 // Therefore do not apply address-based whitelist permissions to them.
1788 AddWhitelistPermissionFlags(permission_flags, inbound_onion ? std::optional<CNetAddr>{} : addr, vWhitelistedRangeIncoming);
1789
1790 {
1791 LOCK(m_nodes_mutex);
1792 for (const CNode* pnode : m_nodes) {
1793 if (pnode->IsInboundConn()) nInbound++;
1794 }
1795 }
1796
1797 if (!fNetworkActive) {
1798 LogDebug(BCLog::NET, "connection from %s dropped: not accepting new connections\n", addr.ToStringAddrPort());
1799 return;
1800 }
1801
1802 if (!sock->IsSelectable()) {
1803 LogInfo("connection from %s dropped: non-selectable socket\n", addr.ToStringAddrPort());
1804 return;
1805 }
1806
1807 // According to the internet TCP_NODELAY is not carried into accepted sockets
1808 // on all platforms. Set it again here just to be sure.
1809 const int on{1};
1810 if (sock->SetSockOpt(IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on)) == SOCKET_ERROR) {
1811 LogDebug(BCLog::NET, "connection from %s: unable to set TCP_NODELAY, continuing anyway\n",
1812 addr.ToStringAddrPort());
1813 }
1814
1815 // Don't accept connections from banned peers.
1816 bool banned = m_banman && m_banman->IsBanned(addr);
1817 if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && banned)
1818 {
1819 LogDebug(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToStringAddrPort());
1820 return;
1821 }
1822
1823 // Only accept connections from discouraged peers if our inbound slots aren't (almost) full.
1824 bool discouraged = m_banman && m_banman->IsDiscouraged(addr);
1825 if (!NetPermissions::HasFlag(permission_flags, NetPermissionFlags::NoBan) && nInbound + 1 >= m_max_inbound && discouraged)
1826 {
1827 LogDebug(BCLog::NET, "connection from %s dropped (discouraged)\n", addr.ToStringAddrPort());
1828 return;
1829 }
1830
1831 if (nInbound >= m_max_inbound)
1832 {
1833 if (!AttemptToEvictConnection()) {
1834 // No connection to evict, disconnect the new connection
1835 LogDebug(BCLog::NET, "failed to find an eviction candidate - connection dropped (full)\n");
1836 return;
1837 }
1838 }
1839
1840 NodeId id = GetNewNodeId();
1841 uint64_t nonce = GetDeterministicRandomizer(RANDOMIZER_ID_LOCALHOSTNONCE).Write(id).Finalize();
1842
1843 // The V2Transport transparently falls back to V1 behavior when an incoming V1 connection is
1844 // detected, so use it whenever we signal NODE_P2P_V2.
1845 ServiceFlags local_services = GetLocalServices();
1846 const bool use_v2transport(local_services & NODE_P2P_V2);
1847
1848 uint64_t network_id = GetDeterministicRandomizer(RANDOMIZER_ID_NETWORKKEY)
1849 .Write(inbound_onion ? NET_ONION : addr.GetNetClass())
1850 .Write(addr_bind.GetAddrBytes())
1851 .Write(addr_bind.GetPort()) // inbound connections use bind port
1852 .Finalize();
1853 CNode* pnode = new CNode(id,
1854 std::move(sock),
1855 CAddress{addr, NODE_NONE},
1856 CalculateKeyedNetGroup(addr),
1857 nonce,
1858 addr_bind,
1859 /*addrNameIn=*/"",
1860 ConnectionType::INBOUND,
1861 inbound_onion,
1862 network_id,
1863 CNodeOptions{
1864 .permission_flags = permission_flags,
1865 .prefer_evict = discouraged,
1866 .recv_flood_size = nReceiveFloodSize,
1867 .use_v2transport = use_v2transport,
1868 });
1869 pnode->AddRef();
1870 m_msgproc->InitializeNode(*pnode, local_services);
1871 {
1872 LOCK(m_nodes_mutex);
1873 m_nodes.push_back(pnode);
1874 }
1875 LogDebug(BCLog::NET, "connection from %s accepted\n", addr.ToStringAddrPort());
1876 TRACEPOINT(net, inbound_connection,
1877 pnode->GetId(),
1878 pnode->m_addr_name.c_str(),
1879 pnode->ConnectionTypeAsString().c_str(),
1880 pnode->ConnectedThroughNetwork(),
1881 GetNodeCount(ConnectionDirection::In));
1882
1883 // We received a new connection, harvest entropy from the time (and our peer count)
1884 RandAddEvent((uint32_t)id);
1885 }
1886
1887 bool CConnman::AddConnection(const std::string& address, ConnectionType conn_type, bool use_v2transport = false)
1888 {
1889 AssertLockNotHeld(m_nodes_mutex);
1890 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
1891 std::optional<int> max_connections;
1892 switch (conn_type) {
1893 case ConnectionType::INBOUND:
1894 case ConnectionType::MANUAL:
1895 case ConnectionType::PRIVATE_BROADCAST:
1896 return false;
1897 case ConnectionType::OUTBOUND_FULL_RELAY:
1898 max_connections = m_max_outbound_full_relay;
1899 break;
1900 case ConnectionType::BLOCK_RELAY:
1901 max_connections = m_max_outbound_block_relay;
1902 break;
1903 // no limit for ADDR_FETCH because -seednode has no limit either
1904 case ConnectionType::ADDR_FETCH:
1905 break;
1906 // no limit for FEELER connections since they're short-lived
1907 case ConnectionType::FEELER:
1908 break;
1909 } // no default case, so the compiler can warn about missing cases
1910
1911 // Count existing connections
1912 int existing_connections = WITH_LOCK(m_nodes_mutex,
1913 return std::count_if(m_nodes.begin(), m_nodes.end(), [conn_type](CNode* node) { return node->m_conn_type == conn_type; }););
1914
1915 // Max connections of specified type already exist
1916 if (max_connections != std::nullopt && existing_connections >= max_connections) return false;
1917
1918 // Max total outbound connections already exist
1919 CountingSemaphoreGrant<> grant(*semOutbound, true);
1920 if (!grant) return false;
1921
1922 OpenNetworkConnection(/*addrConnect=*/CAddress{},
1923 /*fCountFailure=*/false,
1924 /*grant_outbound=*/std::move(grant),
1925 /*pszDest=*/address.c_str(),
1926 /*conn_type=*/conn_type,
1927 /*use_v2transport=*/use_v2transport,
1928 /*proxy_override=*/std::nullopt);
1929 return true;
1930 }
1931
1932 void CConnman::DisconnectNodes()
1933 {
1934 AssertLockNotHeld(m_nodes_mutex);
1935 AssertLockNotHeld(m_reconnections_mutex);
1936
1937 // Use a temporary variable to accumulate desired reconnections, so we don't need
1938 // m_reconnections_mutex while holding m_nodes_mutex.
1939 decltype(m_reconnections) reconnections_to_add;
1940
1941 {
1942 LOCK(m_nodes_mutex);
1943
1944 const bool network_active{fNetworkActive};
1945 if (!network_active) {
1946 // Disconnect any connected nodes
1947 for (CNode* pnode : m_nodes) {
1948 if (!pnode->fDisconnect) {
1949 LogDebug(BCLog::NET, "Network not active, %s", pnode->DisconnectMsg());
1950 pnode->fDisconnect = true;
1951 }
1952 }
1953 }
1954
1955 // Disconnect unused nodes
1956 std::vector<CNode*> nodes_copy = m_nodes;
1957 for (CNode* pnode : nodes_copy)
1958 {
1959 if (pnode->fDisconnect)
1960 {
1961 // remove from m_nodes
1962 m_nodes.erase(remove(m_nodes.begin(), m_nodes.end(), pnode), m_nodes.end());
1963
1964 // Add to reconnection list if appropriate. We don't reconnect right here, because
1965 // the creation of a connection is a blocking operation (up to several seconds),
1966 // and we don't want to hold up the socket handler thread for that long.
1967 if (network_active && pnode->m_transport->ShouldReconnectV1()) {
1968 reconnections_to_add.push_back({
1969 .proxy_override = pnode->m_proxy_override,
1970 .addr_connect = pnode->addr,
1971 .grant = std::move(pnode->grantOutbound),
1972 .destination = pnode->m_dest,
1973 .conn_type = pnode->m_conn_type,
1974 .use_v2transport = false});
1975 LogDebug(BCLog::NET, "retrying with v1 transport protocol for peer=%d\n", pnode->GetId());
1976 }
1977
1978 // release outbound grant (if any)
1979 pnode->grantOutbound.Release();
1980
1981 // close socket and cleanup
1982 pnode->CloseSocketDisconnect();
1983
1984 // update connection count by network
1985 if (pnode->IsManualOrFullOutboundConn()) --m_network_conn_counts[pnode->addr.GetNetwork()];
1986
1987 // hold in disconnected pool until all refs are released
1988 pnode->Release();
1989 m_nodes_disconnected.push_back(pnode);
1990 }
1991 }
1992 }
1993 {
1994 // Delete disconnected nodes
1995 std::list<CNode*> nodes_disconnected_copy = m_nodes_disconnected;
1996 for (CNode* pnode : nodes_disconnected_copy)
1997 {
1998 // Destroy the object only after other threads have stopped using it.
1999 if (pnode->GetRefCount() <= 0) {
2000 m_nodes_disconnected.remove(pnode);
2001 DeleteNode(pnode);
2002 }
2003 }
2004 }
2005 {
2006 // Move entries from reconnections_to_add to m_reconnections.
2007 LOCK(m_reconnections_mutex);
2008 m_reconnections.splice(m_reconnections.end(), std::move(reconnections_to_add));
2009 }
2010 }
2011
2012 void CConnman::NotifyNumConnectionsChanged()
2013 {
2014 AssertLockNotHeld(m_nodes_mutex);
2015
2016 size_t nodes_size;
2017 {
2018 LOCK(m_nodes_mutex);
2019 nodes_size = m_nodes.size();
2020 }
2021 if(nodes_size != nPrevNodeCount) {
2022 nPrevNodeCount = nodes_size;
2023 if (m_client_interface) {
2024 m_client_interface->NotifyNumConnectionsChanged(nodes_size);
2025 }
2026 }
2027 }
2028
2029 bool CConnman::ShouldRunInactivityChecks(const CNode& node, NodeClock::time_point now) const
2030 {
2031 return node.m_connected + m_peer_connect_timeout < now;
2032 }
2033
2034 bool CConnman::InactivityCheck(const CNode& node, NodeClock::time_point now) const
2035 {
2036 // Tests that see disconnects after using mocktime can start nodes with a
2037 // large timeout. For example, -peertimeout=999999999.
2038 const auto last_send{node.m_last_send.load()};
2039 const auto last_recv{node.m_last_recv.load()};
2040
2041 if (!ShouldRunInactivityChecks(node, now)) return false;
2042
2043 bool has_received{last_recv > NodeClock::epoch};
2044 bool has_sent{last_send > NodeClock::epoch};
2045
2046 if (!has_received || !has_sent) {
2047 std::string has_never;
2048 if (!has_received) has_never += ", never received from peer";
2049 if (!has_sent) has_never += ", never sent to peer";
2050 LogDebug(BCLog::NET,
2051 "socket no message in first %i seconds%s, %s",
2052 count_seconds(m_peer_connect_timeout),
2053 has_never,
2054 node.DisconnectMsg()
2055 );
2056 return true;
2057 }
2058
2059 if (now > last_send + TIMEOUT_INTERVAL) {
2060 LogDebug(BCLog::NET,
2061 "socket sending timeout: %is, %s", Ticks<std::chrono::seconds>(now - last_send),
2062 node.DisconnectMsg()
2063 );
2064 return true;
2065 }
2066
2067 if (now > last_recv + TIMEOUT_INTERVAL) {
2068 LogDebug(BCLog::NET,
2069 "socket receive timeout: %is, %s", Ticks<std::chrono::seconds>(now - last_recv),
2070 node.DisconnectMsg()
2071 );
2072 return true;
2073 }
2074
2075 if (!node.fSuccessfullyConnected) {
2076 if (node.m_transport->GetInfo().transport_type == TransportProtocolType::DETECTING) {
2077 LogDebug(BCLog::NET, "V2 handshake timeout, %s", node.DisconnectMsg());
2078 } else {
2079 LogDebug(BCLog::NET, "version handshake timeout, %s", node.DisconnectMsg());
2080 }
2081 return true;
2082 }
2083
2084 return false;
2085 }
2086
2087 Sock::EventsPerSock CConnman::GenerateWaitSockets(std::span<CNode* const> nodes)
2088 {
2089 Sock::EventsPerSock events_per_sock;
2090
2091 for (const ListenSocket& hListenSocket : vhListenSocket) {
2092 events_per_sock.emplace(hListenSocket.sock, Sock::Events{Sock::RecvEvent});
2093 }
2094
2095 for (CNode* pnode : nodes) {
2096 bool select_recv = !pnode->fPauseRecv;
2097 bool select_send;
2098 {
2099 LOCK(pnode->cs_vSend);
2100 // Sending is possible if either there are bytes to send right now, or if there will be
2101 // once a potential message from vSendMsg is handed to the transport. GetBytesToSend
2102 // determines both of these in a single call.
2103 const auto& [to_send, more, _msg_type] = pnode->m_transport->GetBytesToSend(!pnode->vSendMsg.empty());
2104 select_send = !to_send.empty() || more;
2105 }
2106 if (!select_recv && !select_send) continue;
2107
2108 LOCK(pnode->m_sock_mutex);
2109 if (pnode->m_sock) {
2110 Sock::Event event = (select_send ? Sock::SendEvent : 0) | (select_recv ? Sock::RecvEvent : 0);
2111 events_per_sock.emplace(pnode->m_sock, Sock::Events{event});
2112 }
2113 }
2114
2115 return events_per_sock;
2116 }
2117
2118 void CConnman::SocketHandler()
2119 {
2120 AssertLockNotHeld(m_nodes_mutex);
2121 AssertLockNotHeld(m_total_bytes_sent_mutex);
2122
2123 Sock::EventsPerSock events_per_sock;
2124
2125 {
2126 const NodesSnapshot snap{*this, /*shuffle=*/false};
2127
2128 const auto timeout = std::chrono::milliseconds(SELECT_TIMEOUT_MILLISECONDS);
2129
2130 // Check for the readiness of the already connected sockets and the
2131 // listening sockets in one call ("readiness" as in poll(2) or
2132 // select(2)). If none are ready, wait for a short while and return
2133 // empty sets.
2134 events_per_sock = GenerateWaitSockets(snap.Nodes());
2135 if (events_per_sock.empty() || !events_per_sock.begin()->first->WaitMany(timeout, events_per_sock)) {
2136 m_interrupt_net->sleep_for(timeout);
2137 }
2138
2139 // Service (send/receive) each of the already connected nodes.
2140 SocketHandlerConnected(snap.Nodes(), events_per_sock);
2141 }
2142
2143 // Accept new connections from listening sockets.
2144 SocketHandlerListening(events_per_sock);
2145 }
2146
2147 void CConnman::SocketHandlerConnected(const std::vector<CNode*>& nodes,
2148 const Sock::EventsPerSock& events_per_sock)
2149 {
2150 AssertLockNotHeld(m_total_bytes_sent_mutex);
2151
2152 const auto now{NodeClock::now()};
2153
2154 for (CNode* pnode : nodes) {
2155 if (m_interrupt_net->interrupted()) {
2156 return;
2157 }
2158
2159 //
2160 // Receive
2161 //
2162 bool recvSet = false;
2163 bool sendSet = false;
2164 bool errorSet = false;
2165 {
2166 LOCK(pnode->m_sock_mutex);
2167 if (!pnode->m_sock) {
2168 continue;
2169 }
2170 const auto it = events_per_sock.find(pnode->m_sock);
2171 if (it != events_per_sock.end()) {
2172 recvSet = it->second.occurred & Sock::RecvEvent;
2173 sendSet = it->second.occurred & Sock::SendEvent;
2174 errorSet = it->second.occurred & Sock::ErrorEvent;
2175 }
2176 }
2177
2178 if (sendSet) {
2179 // Send data
2180 auto [bytes_sent, data_left] = WITH_LOCK(pnode->cs_vSend, return SocketSendData(*pnode));
2181 if (bytes_sent) {
2182 RecordBytesSent(bytes_sent);
2183
2184 // If both receiving and (non-optimistic) sending were possible, we first attempt
2185 // sending. If that succeeds, but does not fully drain the send queue, do not
2186 // attempt to receive. This avoids needlessly queueing data if the remote peer
2187 // is slow at receiving data, by means of TCP flow control. We only do this when
2188 // sending actually succeeded to make sure progress is always made; otherwise a
2189 // deadlock would be possible when both sides have data to send, but neither is
2190 // receiving.
2191 if (data_left) recvSet = false;
2192 }
2193 }
2194
2195 if (recvSet || errorSet)
2196 {
2197 // typical socket buffer is 8K-64K
2198 uint8_t pchBuf[0x10000];
2199 int nBytes = 0;
2200 {
2201 LOCK(pnode->m_sock_mutex);
2202 if (!pnode->m_sock) {
2203 continue;
2204 }
2205 nBytes = pnode->m_sock->Recv(pchBuf, sizeof(pchBuf), MSG_DONTWAIT);
2206 }
2207 if (nBytes > 0)
2208 {
2209 bool notify = false;
2210 if (!pnode->ReceiveMsgBytes({pchBuf, (size_t)nBytes}, notify)) {
2211 LogDebug(BCLog::NET,
2212 "receiving message bytes failed, %s",
2213 pnode->DisconnectMsg()
2214 );
2215 pnode->CloseSocketDisconnect();
2216 }
2217 RecordBytesRecv(nBytes);
2218 if (notify) {
2219 pnode->MarkReceivedMsgsForProcessing();
2220 WakeMessageHandler();
2221 }
2222 }
2223 else if (nBytes == 0)
2224 {
2225 // socket closed gracefully
2226 if (!pnode->fDisconnect) {
2227 LogDebug(BCLog::NET, "socket closed, %s", pnode->DisconnectMsg());
2228 }
2229 pnode->CloseSocketDisconnect();
2230 }
2231 else if (nBytes < 0)
2232 {
2233 // error
2234 int nErr = WSAGetLastError();
2235 if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS)
2236 {
2237 if (!pnode->fDisconnect) {
2238 LogDebug(BCLog::NET, "socket recv error, %s: %s", pnode->DisconnectMsg(), NetworkErrorString(nErr));
2239 }
2240 pnode->CloseSocketDisconnect();
2241 }
2242 }
2243 }
2244
2245 if (InactivityCheck(*pnode, now)) pnode->fDisconnect = true;
2246 }
2247 }
2248
2249 void CConnman::SocketHandlerListening(const Sock::EventsPerSock& events_per_sock)
2250 {
2251 AssertLockNotHeld(m_nodes_mutex);
2252
2253 for (const ListenSocket& listen_socket : vhListenSocket) {
2254 if (m_interrupt_net->interrupted()) {
2255 return;
2256 }
2257 const auto it = events_per_sock.find(listen_socket.sock);
2258 if (it != events_per_sock.end() && it->second.occurred & Sock::RecvEvent) {
2259 AcceptConnection(listen_socket);
2260 }
2261 }
2262 }
2263
2264 void CConnman::ThreadSocketHandler()
2265 {
2266 AssertLockNotHeld(m_total_bytes_sent_mutex);
2267
2268 while (!m_interrupt_net->interrupted()) {
2269 DisconnectNodes();
2270 NotifyNumConnectionsChanged();
2271 SocketHandler();
2272 }
2273 }
2274
2275 void CConnman::WakeMessageHandler()
2276 {
2277 {
2278 LOCK(mutexMsgProc);
2279 fMsgProcWake = true;
2280 }
2281 condMsgProc.notify_one();
2282 }
2283
2284 void CConnman::ThreadDNSAddressSeed()
2285 {
2286 int outbound_connection_count = 0;
2287
2288 if (!gArgs.GetArgs("-seednode").empty()) {
2289 auto start = NodeClock::now();
2290 constexpr std::chrono::seconds SEEDNODE_TIMEOUT = 30s;
2291 LogInfo("-seednode enabled. Trying the provided seeds for %d seconds before defaulting to the dnsseeds.\n", SEEDNODE_TIMEOUT.count());
2292 while (!m_interrupt_net->interrupted()) {
2293 if (!m_interrupt_net->sleep_for(500ms)) {
2294 return;
2295 }
2296
2297 // Abort if we have spent enough time without reaching our target.
2298 // Giving seed nodes 30 seconds so this does not become a race against fixedseeds (which triggers after 1 min)
2299 if (NodeClock::now() > start + SEEDNODE_TIMEOUT) {
2300 LogInfo("Couldn't connect to enough peers via seed nodes. Handing fetch logic to the DNS seeds.\n");
2301 break;
2302 }
2303
2304 outbound_connection_count = GetFullOutboundConnCount();
2305 if (outbound_connection_count >= SEED_OUTBOUND_CONNECTION_THRESHOLD) {
2306 LogInfo("P2P peers available. Finished fetching data from seed nodes.\n");
2307 break;
2308 }
2309 }
2310 }
2311
2312 FastRandomContext rng;
2313 std::vector<std::string> seeds = m_params.DNSSeeds();
2314 std::shuffle(seeds.begin(), seeds.end(), rng);
2315 int seeds_right_now = 0; // Number of seeds left before testing if we have enough connections
2316
2317 if (gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED)) {
2318 // When -forcednsseed is provided, query all.
2319 seeds_right_now = seeds.size();
2320 } else if (addrman.get().Size() == 0) {
2321 // If we have no known peers, query all.
2322 // This will occur on the first run, or if peers.dat has been
2323 // deleted.
2324 seeds_right_now = seeds.size();
2325 }
2326
2327 // Proceed with dnsseeds if seednodes hasn't reached the target or if forcednsseed is set
2328 if (outbound_connection_count < SEED_OUTBOUND_CONNECTION_THRESHOLD || seeds_right_now) {
2329 // goal: only query DNS seed if address need is acute
2330 // * If we have a reasonable number of peers in addrman, spend
2331 // some time trying them first. This improves user privacy by
2332 // creating fewer identifying DNS requests, reduces trust by
2333 // giving seeds less influence on the network topology, and
2334 // reduces traffic to the seeds.
2335 // * When querying DNS seeds query a few at once, this ensures
2336 // that we don't give DNS seeds the ability to eclipse nodes
2337 // that query them.
2338 // * If we continue having problems, eventually query all the
2339 // DNS seeds, and if that fails too, also try the fixed seeds.
2340 // (done in ThreadOpenConnections)
2341 int found = 0;
2342 const std::chrono::seconds seeds_wait_time = (addrman.get().Size() >= DNSSEEDS_DELAY_PEER_THRESHOLD ? DNSSEEDS_DELAY_MANY_PEERS : DNSSEEDS_DELAY_FEW_PEERS);
2343
2344 for (const std::string& seed : seeds) {
2345 if (seeds_right_now == 0) {
2346 seeds_right_now += DNSSEEDS_TO_QUERY_AT_ONCE;
2347
2348 if (addrman.get().Size() > 0) {
2349 LogInfo("Waiting %d seconds before querying DNS seeds.\n", seeds_wait_time.count());
2350 std::chrono::seconds to_wait = seeds_wait_time;
2351 while (to_wait.count() > 0) {
2352 // if sleeping for the MANY_PEERS interval, wake up
2353 // early to see if we have enough peers and can stop
2354 // this thread entirely freeing up its resources
2355 std::chrono::seconds w = std::min(DNSSEEDS_DELAY_FEW_PEERS, to_wait);
2356 if (!m_interrupt_net->sleep_for(w)) return;
2357 to_wait -= w;
2358
2359 if (GetFullOutboundConnCount() >= SEED_OUTBOUND_CONNECTION_THRESHOLD) {
2360 if (found > 0) {
2361 LogInfo("%d addresses found from DNS seeds\n", found);
2362 LogInfo("P2P peers available. Finished DNS seeding.\n");
2363 } else {
2364 LogInfo("P2P peers available. Skipped DNS seeding.\n");
2365 }
2366 return;
2367 }
2368 }
2369 }
2370 }
2371
2372 if (m_interrupt_net->interrupted()) return;
2373
2374 // hold off on querying seeds if P2P network deactivated
2375 if (!fNetworkActive) {
2376 LogInfo("Waiting for network to be reactivated before querying DNS seeds.\n");
2377 do {
2378 if (!m_interrupt_net->sleep_for(1s)) return;
2379 } while (!fNetworkActive);
2380 }
2381
2382 LogInfo("Loading addresses from DNS seed %s\n", seed);
2383 // If -proxy is in use, we make an ADDR_FETCH connection to the DNS resolved peer address
2384 // for the base dns seed domain in chainparams
2385 if (HaveNameProxy()) {
2386 AddAddrFetch(seed);
2387 } else {
2388 std::vector<CAddress> vAdd;
2389 constexpr ServiceFlags requiredServiceBits{SeedsServiceFlags()};
2390 std::string host = strprintf("x%x.%s", requiredServiceBits, seed);
2391 CNetAddr resolveSource;
2392 if (!resolveSource.SetInternal(host)) {
2393 continue;
2394 }
2395 // Limit number of IPs learned from a single DNS seed. This limit exists to prevent the results from
2396 // one DNS seed from dominating AddrMan. Note that the number of results from a UDP DNS query is
2397 // bounded to 33 already, but it is possible for it to use TCP where a larger number of results can be
2398 // returned.
2399 unsigned int nMaxIPs = 32;
2400 const auto addresses{LookupHost(host, nMaxIPs, true)};
2401 if (!addresses.empty()) {
2402 for (const CNetAddr& ip : addresses) {
2403 CAddress addr = CAddress(CService(ip, m_params.GetDefaultPort()), requiredServiceBits);
2404 addr.nTime = rng.rand_uniform_delay(Now<NodeSeconds>() - 3 * 24h, -4 * 24h); // use a random age between 3 and 7 days old
2405 vAdd.push_back(addr);
2406 found++;
2407 }
2408 addrman.get().Add(vAdd, resolveSource);
2409 } else {
2410 // If the seed does not support a subdomain with our desired service bits,
2411 // we make an ADDR_FETCH connection to the DNS resolved peer address for the
2412 // base dns seed domain in chainparams
2413 AddAddrFetch(seed);
2414 }
2415 }
2416 --seeds_right_now;
2417 }
2418 LogInfo("%d addresses found from DNS seeds\n", found);
2419 } else {
2420 LogInfo("Skipping DNS seeds. Enough peers have been found\n");
2421 }
2422 }
2423
2424 void CConnman::DumpAddresses()
2425 {
2426 const auto start{SteadyClock::now()};
2427
2428 DumpPeerAddresses(::gArgs, addrman);
2429
2430 LogDebug(BCLog::NET, "Flushed %d addresses to peers.dat %dms",
2431 addrman.get().Size(), Ticks<std::chrono::milliseconds>(SteadyClock::now() - start));
2432 }
2433
2434 void CConnman::ProcessAddrFetch()
2435 {
2436 AssertLockNotHeld(m_nodes_mutex);
2437 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
2438 std::string strDest;
2439 {
2440 LOCK(m_addr_fetches_mutex);
2441 if (m_addr_fetches.empty())
2442 return;
2443 strDest = m_addr_fetches.front();
2444 m_addr_fetches.pop_front();
2445 }
2446 // Attempt v2 connection if we support v2 - we'll reconnect with v1 if our
2447 // peer doesn't support it or immediately disconnects us for another reason.
2448 const bool use_v2transport(GetLocalServices() & NODE_P2P_V2);
2449 CAddress addr;
2450 CountingSemaphoreGrant<> grant(*semOutbound, /*fTry=*/true);
2451 if (grant) {
2452 OpenNetworkConnection(/*addrConnect=*/addr,
2453 /*fCountFailure=*/false,
2454 /*grant_outbound=*/std::move(grant),
2455 /*pszDest=*/strDest.c_str(),
2456 /*conn_type=*/ConnectionType::ADDR_FETCH,
2457 /*use_v2transport=*/use_v2transport,
2458 /*proxy_override=*/std::nullopt);
2459 }
2460 }
2461
2462 bool CConnman::GetTryNewOutboundPeer() const
2463 {
2464 return m_try_another_outbound_peer;
2465 }
2466
2467 void CConnman::SetTryNewOutboundPeer(bool flag)
2468 {
2469 m_try_another_outbound_peer = flag;
2470 LogDebug(BCLog::NET, "setting try another outbound peer=%s\n", flag ? "true" : "false");
2471 }
2472
2473 void CConnman::StartExtraBlockRelayPeers()
2474 {
2475 LogDebug(BCLog::NET, "enabling extra block-relay-only peers\n");
2476 m_start_extra_block_relay_peers = true;
2477 }
2478
2479 // Return the number of outbound connections that are full relay (not blocks only)
2480 int CConnman::GetFullOutboundConnCount() const
2481 {
2482 AssertLockNotHeld(m_nodes_mutex);
2483
2484 int nRelevant = 0;
2485 {
2486 LOCK(m_nodes_mutex);
2487 for (const CNode* pnode : m_nodes) {
2488 if (pnode->fSuccessfullyConnected && pnode->IsFullOutboundConn()) ++nRelevant;
2489 }
2490 }
2491 return nRelevant;
2492 }
2493
2494 // Return the number of peers we have over our outbound connection limit
2495 // Exclude peers that are marked for disconnect, or are going to be
2496 // disconnected soon (eg ADDR_FETCH and FEELER)
2497 // Also exclude peers that haven't finished initial connection handshake yet
2498 // (so that we don't decide we're over our desired connection limit, and then
2499 // evict some peer that has finished the handshake)
2500 int CConnman::GetExtraFullOutboundCount() const
2501 {
2502 AssertLockNotHeld(m_nodes_mutex);
2503
2504 int full_outbound_peers = 0;
2505 {
2506 LOCK(m_nodes_mutex);
2507 for (const CNode* pnode : m_nodes) {
2508 if (pnode->fSuccessfullyConnected && !pnode->fDisconnect && pnode->IsFullOutboundConn()) {
2509 ++full_outbound_peers;
2510 }
2511 }
2512 }
2513 return std::max(full_outbound_peers - m_max_outbound_full_relay, 0);
2514 }
2515
2516 int CConnman::GetExtraBlockRelayCount() const
2517 {
2518 AssertLockNotHeld(m_nodes_mutex);
2519
2520 int block_relay_peers = 0;
2521 {
2522 LOCK(m_nodes_mutex);
2523 for (const CNode* pnode : m_nodes) {
2524 if (pnode->fSuccessfullyConnected && !pnode->fDisconnect && pnode->IsBlockOnlyConn()) {
2525 ++block_relay_peers;
2526 }
2527 }
2528 }
2529 return std::max(block_relay_peers - m_max_outbound_block_relay, 0);
2530 }
2531
2532 std::unordered_set<Network> CConnman::GetReachableEmptyNetworks() const
2533 {
2534 std::unordered_set<Network> networks{};
2535 for (int n = 0; n < NET_MAX; n++) {
2536 enum Network net = (enum Network)n;
2537 if (net == NET_UNROUTABLE || net == NET_INTERNAL) continue;
2538 if (g_reachable_nets.Contains(net) && addrman.get().Size(net, std::nullopt) == 0) {
2539 networks.insert(net);
2540 }
2541 }
2542 return networks;
2543 }
2544
2545 bool CConnman::MultipleManualOrFullOutboundConns(Network net) const
2546 {
2547 AssertLockHeld(m_nodes_mutex);
2548 return m_network_conn_counts[net] > 1;
2549 }
2550
2551 bool CConnman::MaybePickPreferredNetwork(std::optional<Network>& network)
2552 {
2553 AssertLockNotHeld(m_nodes_mutex);
2554
2555 std::array<Network, 5> nets{NET_IPV4, NET_IPV6, NET_ONION, NET_I2P, NET_CJDNS};
2556 std::shuffle(nets.begin(), nets.end(), FastRandomContext());
2557
2558 LOCK(m_nodes_mutex);
2559 for (const auto net : nets) {
2560 if (g_reachable_nets.Contains(net) && m_network_conn_counts[net] == 0 && addrman.get().Size(net) != 0) {
2561 network = net;
2562 return true;
2563 }
2564 }
2565
2566 return false;
2567 }
2568
2569 void CConnman::ThreadOpenConnections(const std::vector<std::string> connect, std::span<const std::string> seed_nodes)
2570 {
2571 AssertLockNotHeld(m_nodes_mutex);
2572 AssertLockNotHeld(m_reconnections_mutex);
2573 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
2574
2575 FastRandomContext rng;
2576 // Connect to specific addresses
2577 if (!connect.empty())
2578 {
2579 // Attempt v2 connection if we support v2 - we'll reconnect with v1 if our
2580 // peer doesn't support it or immediately disconnects us for another reason.
2581 const bool use_v2transport(GetLocalServices() & NODE_P2P_V2);
2582 for (int64_t nLoop = 0;; nLoop++)
2583 {
2584 for (const std::string& strAddr : connect)
2585 {
2586 OpenNetworkConnection(/*addrConnect=*/CAddress{CService{}, NODE_NONE},
2587 /*fCountFailure=*/false,
2588 /*grant_outbound=*/{},
2589 /*pszDest=*/strAddr.c_str(),
2590 /*conn_type=*/ConnectionType::MANUAL,
2591 /*use_v2transport=*/use_v2transport,
2592 /*proxy_override=*/std::nullopt);
2593 for (int i = 0; i < 10 && i < nLoop; i++)
2594 {
2595 if (!m_interrupt_net->sleep_for(500ms)) {
2596 return;
2597 }
2598 }
2599 }
2600 if (!m_interrupt_net->sleep_for(500ms)) {
2601 return;
2602 }
2603 PerformReconnections();
2604 }
2605 }
2606
2607 // Initiate network connections
2608 auto start = GetTime<std::chrono::microseconds>();
2609
2610 // Minimum time before next feeler connection (in microseconds).
2611 auto next_feeler = start + rng.rand_exp_duration(FEELER_INTERVAL);
2612 auto next_extra_block_relay = start + rng.rand_exp_duration(EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
2613 auto next_extra_network_peer{start + rng.rand_exp_duration(EXTRA_NETWORK_PEER_INTERVAL)};
2614 const bool dnsseed = gArgs.GetBoolArg("-dnsseed", DEFAULT_DNSSEED);
2615 bool add_fixed_seeds = gArgs.GetBoolArg("-fixedseeds", DEFAULT_FIXEDSEEDS);
2616 const bool use_seednodes{!gArgs.GetArgs("-seednode").empty()};
2617
2618 auto seed_node_timer = NodeClock::now();
2619 bool add_addr_fetch{addrman.get().Size() == 0 && !seed_nodes.empty()};
2620 constexpr std::chrono::seconds ADD_NEXT_SEEDNODE = 10s;
2621
2622 if (!add_fixed_seeds) {
2623 LogInfo("Fixed seeds are disabled\n");
2624 }
2625
2626 while (!m_interrupt_net->interrupted()) {
2627 if (add_addr_fetch) {
2628 add_addr_fetch = false;
2629 const auto& seed{SpanPopBack(seed_nodes)};
2630 AddAddrFetch(seed);
2631
2632 if (addrman.get().Size() == 0) {
2633 LogInfo("Empty addrman, adding seednode (%s) to addrfetch\n", seed);
2634 } else {
2635 LogInfo("Couldn't connect to peers from addrman after %d seconds. Adding seednode (%s) to addrfetch\n", ADD_NEXT_SEEDNODE.count(), seed);
2636 }
2637 }
2638
2639 ProcessAddrFetch();
2640
2641 if (!m_interrupt_net->sleep_for(500ms)) {
2642 return;
2643 }
2644
2645 PerformReconnections();
2646
2647 CountingSemaphoreGrant<> grant(*semOutbound);
2648 if (m_interrupt_net->interrupted()) {
2649 return;
2650 }
2651
2652 const std::unordered_set<Network> fixed_seed_networks{GetReachableEmptyNetworks()};
2653 if (add_fixed_seeds && !fixed_seed_networks.empty()) {
2654 // When the node starts with an empty peers.dat, there are a few other sources of peers before
2655 // we fallback on to fixed seeds: -dnsseed, -seednode, -addnode
2656 // If none of those are available, we fallback on to fixed seeds immediately, else we allow
2657 // 60 seconds for any of those sources to populate addrman.
2658 bool add_fixed_seeds_now = false;
2659 // It is cheapest to check if enough time has passed first.
2660 if (GetTime<std::chrono::seconds>() > start + std::chrono::minutes{1}) {
2661 add_fixed_seeds_now = true;
2662 LogInfo("Adding fixed seeds as 60 seconds have passed and addrman is empty for at least one reachable network\n");
2663 }
2664
2665 // Perform cheap checks before locking a mutex.
2666 else if (!dnsseed && !use_seednodes) {
2667 LOCK(m_added_nodes_mutex);
2668 if (m_added_node_params.empty()) {
2669 add_fixed_seeds_now = true;
2670 LogInfo("Adding fixed seeds as -dnsseed=0 (or IPv4/IPv6 connections are disabled via -onlynet) and neither -addnode nor -seednode are provided\n");
2671 }
2672 }
2673
2674 if (add_fixed_seeds_now) {
2675 std::vector<CAddress> seed_addrs{ConvertSeeds(m_params.FixedSeeds())};
2676 // We will not make outgoing connections to peers that are unreachable
2677 // (e.g. because of -onlynet configuration).
2678 // Therefore, we do not add them to addrman in the first place.
2679 // In case previously unreachable networks become reachable
2680 // (e.g. in case of -onlynet changes by the user), fixed seeds will
2681 // be loaded only for networks for which we have no addresses.
2682 seed_addrs.erase(std::remove_if(seed_addrs.begin(), seed_addrs.end(),
2683 [&fixed_seed_networks](const CAddress& addr) { return !fixed_seed_networks.contains(addr.GetNetwork()); }),
2684 seed_addrs.end());
2685 CNetAddr local;
2686 local.SetInternal("fixedseeds");
2687 addrman.get().Add(seed_addrs, local);
2688 add_fixed_seeds = false;
2689 LogInfo("Added %d fixed seeds from reachable networks.\n", seed_addrs.size());
2690 }
2691 }
2692
2693 //
2694 // Choose an address to connect to based on most recently seen
2695 //
2696 CAddress addrConnect;
2697
2698 // Only connect out to one peer per ipv4/ipv6 network group (/16 for IPv4).
2699 int nOutboundFullRelay = 0;
2700 int nOutboundBlockRelay = 0;
2701 int outbound_privacy_network_peers = 0;
2702 std::set<std::vector<unsigned char>> outbound_ipv46_peer_netgroups;
2703
2704 {
2705 LOCK(m_nodes_mutex);
2706 for (const CNode* pnode : m_nodes) {
2707 if (pnode->IsFullOutboundConn()) nOutboundFullRelay++;
2708 if (pnode->IsBlockOnlyConn()) nOutboundBlockRelay++;
2709
2710 // Make sure our persistent outbound slots to ipv4/ipv6 peers belong to different netgroups.
2711 switch (pnode->m_conn_type) {
2712 // We currently don't take inbound connections into account. Since they are
2713 // free to make, an attacker could make them to prevent us from connecting to
2714 // certain peers.
2715 case ConnectionType::INBOUND:
2716 // Short-lived outbound connections should not affect how we select outbound
2717 // peers from addrman.
2718 case ConnectionType::ADDR_FETCH:
2719 case ConnectionType::FEELER:
2720 case ConnectionType::PRIVATE_BROADCAST:
2721 break;
2722 case ConnectionType::MANUAL:
2723 case ConnectionType::OUTBOUND_FULL_RELAY:
2724 case ConnectionType::BLOCK_RELAY:
2725 const CAddress address{pnode->addr};
2726 if (address.IsTor() || address.IsI2P() || address.IsCJDNS()) {
2727 // Since our addrman-groups for these networks are
2728 // random, without relation to the route we
2729 // take to connect to these peers or to the
2730 // difficulty in obtaining addresses with diverse
2731 // groups, we don't worry about diversity with
2732 // respect to our addrman groups when connecting to
2733 // these networks.
2734 ++outbound_privacy_network_peers;
2735 } else {
2736 outbound_ipv46_peer_netgroups.insert(m_netgroupman.GetGroup(address));
2737 }
2738 } // no default case, so the compiler can warn about missing cases
2739 }
2740 }
2741
2742 if (!seed_nodes.empty() && nOutboundFullRelay < SEED_OUTBOUND_CONNECTION_THRESHOLD) {
2743 if (NodeClock::now() > seed_node_timer + ADD_NEXT_SEEDNODE) {
2744 seed_node_timer = NodeClock::now();
2745 add_addr_fetch = true;
2746 }
2747 }
2748
2749 ConnectionType conn_type = ConnectionType::OUTBOUND_FULL_RELAY;
2750 auto now = GetTime<std::chrono::microseconds>();
2751 bool anchor = false;
2752 bool fFeeler = false;
2753 std::optional<Network> preferred_net;
2754
2755 // Determine what type of connection to open. Opening
2756 // BLOCK_RELAY connections to addresses from anchors.dat gets the highest
2757 // priority. Then we open OUTBOUND_FULL_RELAY priority until we
2758 // meet our full-relay capacity. Then we open BLOCK_RELAY connection
2759 // until we hit our block-relay-only peer limit.
2760 // GetTryNewOutboundPeer() gets set when a stale tip is detected, so we
2761 // try opening an additional OUTBOUND_FULL_RELAY connection. If none of
2762 // these conditions are met, check to see if it's time to try an extra
2763 // block-relay-only peer (to confirm our tip is current, see below) or the next_feeler
2764 // timer to decide if we should open a FEELER.
2765
2766 if (!m_anchors.empty() && (nOutboundBlockRelay < m_max_outbound_block_relay)) {
2767 conn_type = ConnectionType::BLOCK_RELAY;
2768 anchor = true;
2769 } else if (nOutboundFullRelay < m_max_outbound_full_relay) {
2770 // OUTBOUND_FULL_RELAY
2771 } else if (nOutboundBlockRelay < m_max_outbound_block_relay) {
2772 conn_type = ConnectionType::BLOCK_RELAY;
2773 } else if (GetTryNewOutboundPeer()) {
2774 // OUTBOUND_FULL_RELAY
2775 } else if (now > next_extra_block_relay && m_start_extra_block_relay_peers) {
2776 // Periodically connect to a peer (using regular outbound selection
2777 // methodology from addrman) and stay connected long enough to sync
2778 // headers, but not much else.
2779 //
2780 // Then disconnect the peer, if we haven't learned anything new.
2781 //
2782 // The idea is to make eclipse attacks very difficult to pull off,
2783 // because every few minutes we're finding a new peer to learn headers
2784 // from.
2785 //
2786 // This is similar to the logic for trying extra outbound (full-relay)
2787 // peers, except:
2788 // - we do this all the time on an exponential timer, rather than just when
2789 // our tip is stale
2790 // - we potentially disconnect our next-youngest block-relay-only peer, if our
2791 // newest block-relay-only peer delivers a block more recently.
2792 // See the eviction logic in net_processing.cpp.
2793 //
2794 // Because we can promote these connections to block-relay-only
2795 // connections, they do not get their own ConnectionType enum
2796 // (similar to how we deal with extra outbound peers).
2797 next_extra_block_relay = now + rng.rand_exp_duration(EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
2798 conn_type = ConnectionType::BLOCK_RELAY;
2799 } else if (now > next_feeler) {
2800 next_feeler = now + rng.rand_exp_duration(FEELER_INTERVAL);
2801 conn_type = ConnectionType::FEELER;
2802 fFeeler = true;
2803 } else if (nOutboundFullRelay == m_max_outbound_full_relay &&
2804 m_max_outbound_full_relay == MAX_OUTBOUND_FULL_RELAY_CONNECTIONS &&
2805 now > next_extra_network_peer &&
2806 MaybePickPreferredNetwork(preferred_net)) {
2807 // Full outbound connection management: Attempt to get at least one
2808 // outbound peer from each reachable network by making extra connections
2809 // and then protecting "only" peers from a network during outbound eviction.
2810 // This is not attempted if the user changed -maxconnections to a value
2811 // so low that less than MAX_OUTBOUND_FULL_RELAY_CONNECTIONS are made,
2812 // to prevent interactions with otherwise protected outbound peers.
2813 next_extra_network_peer = now + rng.rand_exp_duration(EXTRA_NETWORK_PEER_INTERVAL);
2814 } else {
2815 // skip to next iteration of while loop
2816 continue;
2817 }
2818
2819 addrman.get().ResolveCollisions();
2820
2821 const auto current_time{NodeClock::now()};
2822 int nTries = 0;
2823 const auto reachable_nets{g_reachable_nets.All()};
2824
2825 while (!m_interrupt_net->interrupted()) {
2826 if (anchor && !m_anchors.empty()) {
2827 const CAddress addr = m_anchors.back();
2828 m_anchors.pop_back();
2829 if (!addr.IsValid() || IsLocal(addr) || !g_reachable_nets.Contains(addr) ||
2830 !m_msgproc->HasAllDesirableServiceFlags(addr.nServices) ||
2831 outbound_ipv46_peer_netgroups.contains(m_netgroupman.GetGroup(addr))) continue;
2832 addrConnect = addr;
2833 LogDebug(BCLog::NET, "Trying to make an anchor connection to %s\n", addrConnect.ToStringAddrPort());
2834 break;
2835 }
2836
2837 // If we didn't find an appropriate destination after trying 100 addresses fetched from addrman,
2838 // stop this loop, and let the outer loop run again (which sleeps, adds seed nodes, recalculates
2839 // already-connected network ranges, ...) before trying new addrman addresses.
2840 nTries++;
2841 if (nTries > 100)
2842 break;
2843
2844 CAddress addr;
2845 NodeSeconds addr_last_try{0s};
2846
2847 if (fFeeler) {
2848 // First, try to get a tried table collision address. This returns
2849 // an empty (invalid) address if there are no collisions to try.
2850 std::tie(addr, addr_last_try) = addrman.get().SelectTriedCollision();
2851
2852 if (!addr.IsValid()) {
2853 // No tried table collisions. Select a new table address
2854 // for our feeler.
2855 std::tie(addr, addr_last_try) = addrman.get().Select(true, reachable_nets);
2856 } else if (AlreadyConnectedToAddress(addr)) {
2857 // If test-before-evict logic would have us connect to a
2858 // peer that we're already connected to, just mark that
2859 // address as Good(). We won't be able to initiate the
2860 // connection anyway, so this avoids inadvertently evicting
2861 // a currently-connected peer.
2862 addrman.get().Good(addr);
2863 // Select a new table address for our feeler instead.
2864 std::tie(addr, addr_last_try) = addrman.get().Select(true, reachable_nets);
2865 }
2866 } else {
2867 // Not a feeler
2868 // If preferred_net has a value set, pick an extra outbound
2869 // peer from that network. The eviction logic in net_processing
2870 // ensures that a peer from another network will be evicted.
2871 std::tie(addr, addr_last_try) = preferred_net.has_value()
2872 ? addrman.get().Select(false, {*preferred_net})
2873 : addrman.get().Select(false, reachable_nets);
2874 }
2875
2876 // Require outbound IPv4/IPv6 connections, other than feelers, to be to distinct network groups
2877 if (!fFeeler && outbound_ipv46_peer_netgroups.contains(m_netgroupman.GetGroup(addr))) {
2878 continue;
2879 }
2880
2881 // if we selected an invalid or local address, restart
2882 if (!addr.IsValid() || IsLocal(addr)) {
2883 break;
2884 }
2885
2886 if (!g_reachable_nets.Contains(addr)) {
2887 continue;
2888 }
2889
2890 // only consider very recently tried nodes after 30 failed attempts
2891 if (current_time - addr_last_try < 10min && nTries < 30) {
2892 continue;
2893 }
2894
2895 // for non-feelers, require all the services we'll want,
2896 // for feelers, only require they be a full node (only because most
2897 // SPV clients don't have a good address DB available)
2898 if (!fFeeler && !m_msgproc->HasAllDesirableServiceFlags(addr.nServices)) {
2899 continue;
2900 } else if (fFeeler && !MayHaveUsefulAddressDB(addr.nServices)) {
2901 continue;
2902 }
2903
2904 // Do not connect to bad ports, unless 50 invalid addresses have been selected already.
2905 if (nTries < 50 && (addr.IsIPv4() || addr.IsIPv6()) && IsBadPort(addr.GetPort())) {
2906 continue;
2907 }
2908
2909 // Do not make automatic outbound connections to addnode peers, to
2910 // not use our limited outbound slots for them and to ensure
2911 // addnode connections benefit from their intended protections.
2912 if (AddedNodesContain(addr)) {
2913 LogDebug(BCLog::NET, "Not making automatic %s%s connection to %s peer selected for manual (addnode) connection%s\n",
2914 preferred_net.has_value() ? "network-specific " : "",
2915 ConnectionTypeAsString(conn_type), GetNetworkName(addr.GetNetwork()),
2916 fLogIPs ? strprintf(": %s", addr.ToStringAddrPort()) : "");
2917 continue;
2918 }
2919
2920 addrConnect = addr;
2921 break;
2922 }
2923
2924 if (addrConnect.IsValid()) {
2925 if (fFeeler) {
2926 // Add small amount of random noise before connection to avoid synchronization.
2927 if (!m_interrupt_net->sleep_for(rng.rand_uniform_duration<CThreadInterrupt::Clock>(FEELER_SLEEP_WINDOW))) {
2928 return;
2929 }
2930 LogDebug(BCLog::NET, "Making feeler connection to %s\n", addrConnect.ToStringAddrPort());
2931 }
2932
2933 if (preferred_net != std::nullopt) LogDebug(BCLog::NET, "Making network specific connection to %s on %s.\n", addrConnect.ToStringAddrPort(), GetNetworkName(preferred_net.value()));
2934
2935 // Record addrman failure attempts when node has at least 2 persistent outbound connections to peers with
2936 // different netgroups in ipv4/ipv6 networks + all peers in Tor/I2P/CJDNS networks.
2937 // Don't record addrman failure attempts when node is offline. This can be identified since all local
2938 // network connections (if any) belong in the same netgroup, and the size of `outbound_ipv46_peer_netgroups` would only be 1.
2939 const bool count_failures{((int)outbound_ipv46_peer_netgroups.size() + outbound_privacy_network_peers) >= std::min(m_max_automatic_connections - 1, 2)};
2940 // Use BIP324 transport when both us and them have NODE_V2_P2P set.
2941 const bool use_v2transport(addrConnect.nServices & GetLocalServices() & NODE_P2P_V2);
2942 OpenNetworkConnection(/*addrConnect=*/addrConnect,
2943 /*fCountFailure=*/count_failures,
2944 /*grant_outbound=*/std::move(grant),
2945 /*pszDest=*/nullptr,
2946 /*conn_type=*/conn_type,
2947 /*use_v2transport=*/use_v2transport,
2948 /*proxy_override=*/std::nullopt);
2949 }
2950 }
2951 }
2952
2953 std::vector<CAddress> CConnman::GetCurrentBlockRelayOnlyConns() const
2954 {
2955 AssertLockNotHeld(m_nodes_mutex);
2956 std::vector<CAddress> ret;
2957 LOCK(m_nodes_mutex);
2958 for (const CNode* pnode : m_nodes) {
2959 if (pnode->IsBlockOnlyConn()) {
2960 ret.push_back(pnode->addr);
2961 }
2962 }
2963
2964 return ret;
2965 }
2966
2967 std::vector<AddedNodeInfo> CConnman::GetAddedNodeInfo(bool include_connected) const
2968 {
2969 AssertLockNotHeld(m_nodes_mutex);
2970
2971 std::vector<AddedNodeInfo> ret;
2972
2973 std::list<AddedNodeParams> lAddresses(0);
2974 {
2975 LOCK(m_added_nodes_mutex);
2976 ret.reserve(m_added_node_params.size());
2977 std::copy(m_added_node_params.cbegin(), m_added_node_params.cend(), std::back_inserter(lAddresses));
2978 }
2979
2980
2981 // Build a map of all already connected addresses (by IP:port and by name) to inbound/outbound and resolved CService
2982 std::map<CService, bool> mapConnected;
2983 std::map<std::string, std::pair<bool, CService>> mapConnectedByName;
2984 {
2985 LOCK(m_nodes_mutex);
2986 for (const CNode* pnode : m_nodes) {
2987 if (pnode->addr.IsValid()) {
2988 mapConnected[pnode->addr] = pnode->IsInboundConn();
2989 }
2990 std::string addrName{pnode->m_addr_name};
2991 if (!addrName.empty()) {
2992 mapConnectedByName[std::move(addrName)] = std::make_pair(pnode->IsInboundConn(), static_cast<const CService&>(pnode->addr));
2993 }
2994 }
2995 }
2996
2997 for (const auto& addr : lAddresses) {
2998 CService service{MaybeFlipIPv6toCJDNS(LookupNumeric(addr.m_added_node, GetDefaultPort(addr.m_added_node)))};
2999 AddedNodeInfo addedNode{addr, CService(), false, false};
3000 if (service.IsValid()) {
3001 // strAddNode is an IP:port
3002 auto it = mapConnected.find(service);
3003 if (it != mapConnected.end()) {
3004 if (!include_connected) {
3005 continue;
3006 }
3007 addedNode.resolvedAddress = service;
3008 addedNode.fConnected = true;
3009 addedNode.fInbound = it->second;
3010 }
3011 } else {
3012 // strAddNode is a name
3013 auto it = mapConnectedByName.find(addr.m_added_node);
3014 if (it != mapConnectedByName.end()) {
3015 if (!include_connected) {
3016 continue;
3017 }
3018 addedNode.resolvedAddress = it->second.second;
3019 addedNode.fConnected = true;
3020 addedNode.fInbound = it->second.first;
3021 }
3022 }
3023 ret.emplace_back(std::move(addedNode));
3024 }
3025
3026 return ret;
3027 }
3028
3029 void CConnman::ThreadOpenAddedConnections()
3030 {
3031 AssertLockNotHeld(m_nodes_mutex);
3032 AssertLockNotHeld(m_reconnections_mutex);
3033 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
3034
3035 while (true)
3036 {
3037 CountingSemaphoreGrant<> grant(*semAddnode);
3038 std::vector<AddedNodeInfo> vInfo = GetAddedNodeInfo(/*include_connected=*/false);
3039 bool tried = false;
3040 for (const AddedNodeInfo& info : vInfo) {
3041 if (!grant) {
3042 // If we've used up our semaphore and need a new one, let's not wait here since while we are waiting
3043 // the addednodeinfo state might change.
3044 break;
3045 }
3046 tried = true;
3047 OpenNetworkConnection(/*addrConnect=*/CAddress{CService{}, NODE_NONE},
3048 /*fCountFailure=*/false,
3049 /*grant_outbound=*/std::move(grant),
3050 /*pszDest=*/info.m_params.m_added_node.c_str(),
3051 /*conn_type=*/ConnectionType::MANUAL,
3052 /*use_v2transport=*/info.m_params.m_use_v2transport,
3053 /*proxy_override=*/std::nullopt);
3054 if (!m_interrupt_net->sleep_for(500ms)) return;
3055 grant = CountingSemaphoreGrant<>(*semAddnode, /*fTry=*/true);
3056 }
3057 // See if any reconnections are desired.
3058 PerformReconnections();
3059 // Retry every 60 seconds if a connection was attempted, otherwise two seconds
3060 if (!m_interrupt_net->sleep_for(tried ? 60s : 2s)) {
3061 return;
3062 }
3063 }
3064 }
3065
3066 // if successful, this moves the passed grant to the constructed node
3067 bool CConnman::OpenNetworkConnection(const CAddress& addrConnect,
3068 bool fCountFailure,
3069 CountingSemaphoreGrant<>&& grant_outbound,
3070 const char* pszDest,
3071 ConnectionType conn_type,
3072 bool use_v2transport,
3073 const std::optional<Proxy>& proxy_override)
3074 {
3075 AssertLockNotHeld(m_nodes_mutex);
3076 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
3077 assert(conn_type != ConnectionType::INBOUND);
3078
3079 //
3080 // Initiate outbound network connection
3081 //
3082 if (m_interrupt_net->interrupted()) {
3083 return false;
3084 }
3085 if (!fNetworkActive) {
3086 return false;
3087 }
3088 if (!pszDest) {
3089 bool banned_or_discouraged = m_banman && (m_banman->IsDiscouraged(addrConnect) || m_banman->IsBanned(addrConnect));
3090 if (IsLocal(addrConnect) || banned_or_discouraged || AlreadyConnectedToAddress(addrConnect)) {
3091 return false;
3092 }
3093 } else if (AlreadyConnectedToHost(pszDest)) {
3094 return false;
3095 }
3096
3097 CNode* pnode = ConnectNode(addrConnect, pszDest, fCountFailure, conn_type, use_v2transport, proxy_override);
3098
3099 if (!pnode)
3100 return false;
3101 pnode->grantOutbound = std::move(grant_outbound);
3102
3103 m_msgproc->InitializeNode(*pnode, m_local_services);
3104 {
3105 LOCK(m_nodes_mutex);
3106 m_nodes.push_back(pnode);
3107
3108 // update connection count by network
3109 if (pnode->IsManualOrFullOutboundConn()) ++m_network_conn_counts[pnode->addr.GetNetwork()];
3110 }
3111
3112 TRACEPOINT(net, outbound_connection,
3113 pnode->GetId(),
3114 pnode->m_addr_name.c_str(),
3115 pnode->ConnectionTypeAsString().c_str(),
3116 pnode->ConnectedThroughNetwork(),
3117 GetNodeCount(ConnectionDirection::Out));
3118
3119 return true;
3120 }
3121
3122 std::optional<Network> CConnman::PrivateBroadcast::PickNetwork(std::optional<Proxy>& proxy) const
3123 {
3124 prevector<4, Network> nets;
3125 std::optional<Proxy> clearnet_proxy;
3126 proxy.reset();
3127 if (g_reachable_nets.Contains(NET_ONION)) {
3128 nets.push_back(NET_ONION);
3129
3130 clearnet_proxy = ProxyForIPv4or6();
3131 if (clearnet_proxy.has_value()) {
3132 if (g_reachable_nets.Contains(NET_IPV4)) {
3133 nets.push_back(NET_IPV4);
3134 }
3135 if (g_reachable_nets.Contains(NET_IPV6)) {
3136 nets.push_back(NET_IPV6);
3137 }
3138 }
3139 }
3140 if (g_reachable_nets.Contains(NET_I2P)) {
3141 nets.push_back(NET_I2P);
3142 }
3143
3144 if (nets.empty()) {
3145 return std::nullopt;
3146 }
3147
3148 const Network net{nets[FastRandomContext{}.randrange(nets.size())]};
3149 if (net == NET_IPV4 || net == NET_IPV6) {
3150 proxy = clearnet_proxy;
3151 }
3152 return net;
3153 }
3154
3155 size_t CConnman::PrivateBroadcast::NumToOpen() const
3156 {
3157 return m_num_to_open;
3158 }
3159
3160 void CConnman::PrivateBroadcast::NumToOpenAdd(size_t n)
3161 {
3162 m_num_to_open += n;
3163 m_num_to_open.notify_all();
3164 }
3165
3166 size_t CConnman::PrivateBroadcast::NumToOpenSub(size_t n)
3167 {
3168 size_t current_value{m_num_to_open.load()};
3169 size_t new_value;
3170 do {
3171 new_value = current_value > n ? current_value - n : 0;
3172 } while (!m_num_to_open.compare_exchange_strong(current_value, new_value));
3173 return new_value;
3174 }
3175
3176 void CConnman::PrivateBroadcast::NumToOpenWait() const
3177 {
3178 m_num_to_open.wait(0);
3179 }
3180
3181 std::optional<Proxy> CConnman::PrivateBroadcast::ProxyForIPv4or6() const
3182 {
3183 if (m_outbound_tor_ok_at_least_once.load()) {
3184 if (const auto tor_proxy = GetProxy(NET_ONION)) {
3185 return tor_proxy;
3186 }
3187 }
3188 return std::nullopt;
3189 }
3190
3191 Mutex NetEventsInterface::g_msgproc_mutex;
3192
3193 void CConnman::ThreadMessageHandler()
3194 {
3195 AssertLockNotHeld(m_nodes_mutex);
3196
3197 LOCK(NetEventsInterface::g_msgproc_mutex);
3198
3199 while (!flagInterruptMsgProc)
3200 {
3201 bool fMoreWork = false;
3202
3203 {
3204 // Randomize the order in which we process messages from/to our peers.
3205 // This prevents attacks in which an attacker exploits having multiple
3206 // consecutive connections in the m_nodes list.
3207 const NodesSnapshot snap{*this, /*shuffle=*/true};
3208
3209 for (CNode* pnode : snap.Nodes()) {
3210 if (pnode->fDisconnect)
3211 continue;
3212
3213 // Receive messages
3214 bool fMoreNodeWork{m_msgproc->ProcessMessages(*pnode, flagInterruptMsgProc)};
3215 fMoreWork |= (fMoreNodeWork && !pnode->fPauseSend);
3216 if (flagInterruptMsgProc)
3217 return;
3218 // Send messages
3219 m_msgproc->SendMessages(*pnode);
3220
3221 if (flagInterruptMsgProc)
3222 return;
3223 }
3224 }
3225
3226 WAIT_LOCK(mutexMsgProc, lock);
3227 if (!fMoreWork) {
3228 condMsgProc.wait_until(lock, std::chrono::steady_clock::now() + std::chrono::milliseconds(100), [this]() EXCLUSIVE_LOCKS_REQUIRED(mutexMsgProc) { return fMsgProcWake; });
3229 }
3230 fMsgProcWake = false;
3231 }
3232 }
3233
3234 void CConnman::ThreadI2PAcceptIncoming()
3235 {
3236 AssertLockNotHeld(m_nodes_mutex);
3237
3238 static constexpr auto err_wait_begin = 1s;
3239 static constexpr auto err_wait_cap = 5min;
3240 auto err_wait = err_wait_begin;
3241
3242 bool advertising_listen_addr = false;
3243 i2p::Connection conn;
3244
3245 auto SleepOnFailure = [&]() {
3246 m_interrupt_net->sleep_for(err_wait);
3247 if (err_wait < err_wait_cap) {
3248 err_wait += 1s;
3249 }
3250 };
3251
3252 while (!m_interrupt_net->interrupted()) {
3253
3254 if (!m_i2p_sam_session->Listen(conn)) {
3255 if (advertising_listen_addr && conn.me.IsValid()) {
3256 RemoveLocal(conn.me);
3257 advertising_listen_addr = false;
3258 }
3259 SleepOnFailure();
3260 continue;
3261 }
3262
3263 if (!advertising_listen_addr) {
3264 AddLocal(conn.me, LOCAL_MANUAL);
3265 advertising_listen_addr = true;
3266 }
3267
3268 if (!m_i2p_sam_session->Accept(conn)) {
3269 SleepOnFailure();
3270 continue;
3271 }
3272
3273 CreateNodeFromAcceptedSocket(std::move(conn.sock), NetPermissionFlags::None, conn.me, conn.peer);
3274
3275 err_wait = err_wait_begin;
3276 }
3277 }
3278
3279 void CConnman::ThreadPrivateBroadcast()
3280 {
3281 AssertLockNotHeld(m_nodes_mutex);
3282 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
3283
3284 size_t addrman_num_bad_addresses{0};
3285 while (!m_interrupt_net->interrupted()) {
3286
3287 if (!fNetworkActive) {
3288 m_interrupt_net->sleep_for(5s);
3289 continue;
3290 }
3291
3292 CountingSemaphoreGrant<> conn_max_grant{m_private_broadcast.m_sem_conn_max}; // Would block if too many are opened.
3293
3294 m_private_broadcast.NumToOpenWait();
3295
3296 if (m_interrupt_net->interrupted()) {
3297 break;
3298 }
3299
3300 std::optional<Proxy> proxy;
3301 const std::optional<Network> net{m_private_broadcast.PickNetwork(proxy)};
3302 if (!net.has_value()) {
3303 LogWarning("Unable to open -privatebroadcast connections: neither Tor nor I2P is reachable");
3304 m_interrupt_net->sleep_for(5s);
3305 continue;
3306 }
3307
3308 const auto [addr, _] = addrman.get().Select(/*new_only=*/false, {net.value()});
3309
3310 if (!addr.IsValid() || IsLocal(addr)) {
3311 ++addrman_num_bad_addresses;
3312 if (addrman_num_bad_addresses > 100) {
3313 LogDebug(BCLog::PRIVBROADCAST, "Connections needed but addrman keeps returning bad addresses, will retry");
3314 m_interrupt_net->sleep_for(500ms);
3315 }
3316 continue;
3317 }
3318 addrman_num_bad_addresses = 0;
3319
3320 auto target_str{addr.ToStringAddrPort()};
3321 if (proxy.has_value()) {
3322 target_str += " through the proxy at " + proxy->ToString();
3323 }
3324
3325 const bool use_v2transport(addr.nServices & GetLocalServices() & NODE_P2P_V2);
3326
3327 if (OpenNetworkConnection(addr,
3328 /*fCountFailure=*/true,
3329 std::move(conn_max_grant),
3330 /*pszDest=*/nullptr,
3331 ConnectionType::PRIVATE_BROADCAST,
3332 use_v2transport,
3333 proxy)) {
3334 const size_t remaining{m_private_broadcast.NumToOpenSub(1)};
3335 LogDebug(BCLog::PRIVBROADCAST, "Socket connected to %s; remaining connections to open: %d", target_str, remaining);
3336 } else {
3337 const size_t remaining{m_private_broadcast.NumToOpen()};
3338 if (remaining == 0) {
3339 LogDebug(BCLog::PRIVBROADCAST, "Failed to connect to %s, will not retry, no more connections needed", target_str);
3340 } else {
3341 LogDebug(BCLog::PRIVBROADCAST, "Failed to connect to %s, will retry to a different address; remaining connections to open: %d", target_str, remaining);
3342 m_interrupt_net->sleep_for(100ms); // Prevent busy loop if OpenNetworkConnection() fails fast repeatedly.
3343 }
3344 }
3345 }
3346 }
3347
3348 bool CConnman::BindListenPort(const CService& addrBind, bilingual_str& strError, NetPermissionFlags permissions)
3349 {
3350 int nOne = 1;
3351
3352 // Create socket for listening for incoming connections
3353 struct sockaddr_storage sockaddr;
3354 socklen_t len = sizeof(sockaddr);
3355 if (!addrBind.GetSockAddr((struct sockaddr*)&sockaddr, &len))
3356 {
3357 strError = Untranslated(strprintf("Bind address family for %s not supported", addrBind.ToStringAddrPort()));
3358 LogError("%s\n", strError.original);
3359 return false;
3360 }
3361
3362 std::unique_ptr<Sock> sock = CreateSock(addrBind.GetSAFamily(), SOCK_STREAM, IPPROTO_TCP);
3363 if (!sock) {
3364 strError = Untranslated(strprintf("Couldn't open socket for incoming connections (socket returned error %s)", NetworkErrorString(WSAGetLastError())));
3365 LogError("%s\n", strError.original);
3366 return false;
3367 }
3368
3369 // Allow binding if the port is still in TIME_WAIT state after
3370 // the program was closed and restarted.
3371 if (sock->SetSockOpt(SOL_SOCKET, SO_REUSEADDR, &nOne, sizeof(int)) == SOCKET_ERROR) {
3372 strError = Untranslated(strprintf("Error setting SO_REUSEADDR on socket: %s, continuing anyway", NetworkErrorString(WSAGetLastError())));
3373 LogInfo("%s\n", strError.original);
3374 }
3375
3376 // some systems don't have IPV6_V6ONLY but are always v6only; others do have the option
3377 // and enable it by default or not. Try to enable it, if possible.
3378 if (addrBind.IsIPv6()) {
3379 #ifdef IPV6_V6ONLY
3380 if (sock->SetSockOpt(IPPROTO_IPV6, IPV6_V6ONLY, &nOne, sizeof(int)) == SOCKET_ERROR) {
3381 strError = Untranslated(strprintf("Error setting IPV6_V6ONLY on socket: %s, continuing anyway", NetworkErrorString(WSAGetLastError())));
3382 LogInfo("%s\n", strError.original);
3383 }
3384 #endif
3385 #ifdef WIN32
3386 int nProtLevel = PROTECTION_LEVEL_UNRESTRICTED;
3387 if (sock->SetSockOpt(IPPROTO_IPV6, IPV6_PROTECTION_LEVEL, &nProtLevel, sizeof(int)) == SOCKET_ERROR) {
3388 strError = Untranslated(strprintf("Error setting IPV6_PROTECTION_LEVEL on socket: %s, continuing anyway", NetworkErrorString(WSAGetLastError())));
3389 LogInfo("%s\n", strError.original);
3390 }
3391 #endif
3392 }
3393
3394 if (sock->Bind(reinterpret_cast<struct sockaddr*>(&sockaddr), len) == SOCKET_ERROR) {
3395 int nErr = WSAGetLastError();
3396 if (nErr == WSAEADDRINUSE)
3397 strError = strprintf(_("Unable to bind to %s on this computer. %s is probably already running."), addrBind.ToStringAddrPort(), CLIENT_NAME);
3398 else
3399 strError = strprintf(_("Unable to bind to %s on this computer (bind returned error %s)"), addrBind.ToStringAddrPort(), NetworkErrorString(nErr));
3400 LogError("%s\n", strError.original);
3401 return false;
3402 }
3403 LogInfo("Bound to %s\n", addrBind.ToStringAddrPort());
3404
3405 // Listen for incoming connections
3406 if (sock->Listen(SOMAXCONN) == SOCKET_ERROR)
3407 {
3408 strError = strprintf(_("Listening for incoming connections failed (listen returned error %s)"), NetworkErrorString(WSAGetLastError()));
3409 LogError("%s\n", strError.original);
3410 return false;
3411 }
3412
3413 vhListenSocket.emplace_back(std::move(sock), permissions);
3414 return true;
3415 }
3416
3417 void Discover()
3418 {
3419 if (!fDiscover)
3420 return;
3421
3422 for (const CNetAddr &addr: GetLocalAddresses()) {
3423 if (AddLocal(addr, LOCAL_IF) && fLogIPs) {
3424 LogInfo("%s: %s\n", __func__, addr.ToStringAddr());
3425 }
3426 }
3427 }
3428
3429 void CConnman::SetNetworkActive(bool active)
3430 {
3431 LogInfo("%s: %s\n", __func__, active);
3432
3433 if (fNetworkActive == active) {
3434 return;
3435 }
3436
3437 fNetworkActive = active;
3438
3439 if (m_client_interface) {
3440 m_client_interface->NotifyNetworkActiveChanged(fNetworkActive);
3441 }
3442 }
3443
3444 CConnman::CConnman(uint64_t nSeed0In,
3445 uint64_t nSeed1In,
3446 AddrMan& addrman_in,
3447 const NetGroupManager& netgroupman,
3448 const CChainParams& params,
3449 bool network_active,
3450 std::shared_ptr<CThreadInterrupt> interrupt_net)
3451 : addrman(addrman_in)
3452 , m_netgroupman{netgroupman}
3453 , nSeed0(nSeed0In)
3454 , nSeed1(nSeed1In)
3455 , m_interrupt_net{interrupt_net}
3456 , m_params(params)
3457 {
3458 SetTryNewOutboundPeer(false);
3459
3460 Options connOptions;
3461 Init(connOptions);
3462 SetNetworkActive(network_active);
3463 }
3464
3465 NodeId CConnman::GetNewNodeId()
3466 {
3467 return nLastNodeId.fetch_add(1, std::memory_order_relaxed);
3468 }
3469
3470 uint16_t CConnman::GetDefaultPort(Network net) const
3471 {
3472 return net == NET_I2P ? I2P_SAM31_PORT : m_params.GetDefaultPort();
3473 }
3474
3475 uint16_t CConnman::GetDefaultPort(const std::string& addr) const
3476 {
3477 CNetAddr a;
3478 return a.SetSpecial(addr) ? GetDefaultPort(a.GetNetwork()) : m_params.GetDefaultPort();
3479 }
3480
3481 bool CConnman::Bind(const CService& addr_, unsigned int flags, NetPermissionFlags permissions)
3482 {
3483 const CService addr{MaybeFlipIPv6toCJDNS(addr_)};
3484
3485 bilingual_str strError;
3486 if (!BindListenPort(addr, strError, permissions)) {
3487 if ((flags & BF_REPORT_ERROR) && m_client_interface) {
3488 m_client_interface->ThreadSafeMessageBox(strError, CClientUIInterface::MSG_ERROR);
3489 }
3490 return false;
3491 }
3492
3493 if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !NetPermissions::HasFlag(permissions, NetPermissionFlags::NoBan)) {
3494 AddLocal(addr, LOCAL_BIND);
3495 }
3496
3497 return true;
3498 }
3499
3500 bool CConnman::InitBinds(const Options& options)
3501 {
3502 for (const auto& addrBind : options.vBinds) {
3503 if (!Bind(addrBind, BF_REPORT_ERROR, NetPermissionFlags::None)) {
3504 return false;
3505 }
3506 }
3507 for (const auto& addrBind : options.vWhiteBinds) {
3508 if (!Bind(addrBind.m_service, BF_REPORT_ERROR, addrBind.m_flags)) {
3509 return false;
3510 }
3511 }
3512 for (const auto& addr_bind : options.onion_binds) {
3513 if (!Bind(addr_bind, BF_REPORT_ERROR | BF_DONT_ADVERTISE, NetPermissionFlags::None)) {
3514 return false;
3515 }
3516 }
3517 if (options.bind_on_any) {
3518 // Don't consider errors to bind on IPv6 "::" fatal because the host OS
3519 // may not have IPv6 support and the user did not explicitly ask us to
3520 // bind on that.
3521 const CService ipv6_any{in6_addr(COMPAT_IN6ADDR_ANY_INIT), GetListenPort()}; // ::
3522 Bind(ipv6_any, BF_NONE, NetPermissionFlags::None);
3523
3524 struct in_addr inaddr_any;
3525 inaddr_any.s_addr = htonl(INADDR_ANY);
3526 const CService ipv4_any{inaddr_any, GetListenPort()}; // 0.0.0.0
3527 if (!Bind(ipv4_any, BF_REPORT_ERROR, NetPermissionFlags::None)) {
3528 return false;
3529 }
3530 }
3531 return true;
3532 }
3533
3534 bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
3535 {
3536 AssertLockNotHeld(m_total_bytes_sent_mutex);
3537 Init(connOptions);
3538
3539 if (fListen && !InitBinds(connOptions)) {
3540 if (m_client_interface) {
3541 m_client_interface->ThreadSafeMessageBox(
3542 _("Failed to listen on any port. Use -listen=0 if you want this."),
3543 CClientUIInterface::MSG_ERROR);
3544 }
3545 return false;
3546 }
3547
3548 if (connOptions.m_i2p_accept_incoming) {
3549 if (const auto i2p_sam = GetProxy(NET_I2P)) {
3550 m_i2p_sam_session = std::make_unique<i2p::sam::Session>(gArgs.GetDataDirNet() / "i2p_private_key",
3551 *i2p_sam, m_interrupt_net);
3552 }
3553 }
3554
3555 // Randomize the order in which we may query seednode to potentially prevent connecting to the same one every restart (and signal that we have restarted)
3556 std::vector<std::string> seed_nodes = connOptions.vSeedNodes;
3557 if (!seed_nodes.empty()) {
3558 std::shuffle(seed_nodes.begin(), seed_nodes.end(), FastRandomContext{});
3559 }
3560
3561 if (m_use_addrman_outgoing) {
3562 // Load addresses from anchors.dat
3563 m_anchors = ReadAnchors(gArgs.GetDataDirNet() / ANCHORS_DATABASE_FILENAME);
3564 if (m_anchors.size() > MAX_BLOCK_RELAY_ONLY_ANCHORS) {
3565 m_anchors.resize(MAX_BLOCK_RELAY_ONLY_ANCHORS);
3566 }
3567 LogInfo("%i block-relay-only anchors will be tried for connections.\n", m_anchors.size());
3568 }
3569
3570 if (m_client_interface) {
3571 m_client_interface->InitMessage(_("Starting network threads…"));
3572 }
3573
3574 fAddressesInitialized = true;
3575
3576 if (semOutbound == nullptr) {
3577 // initialize semaphore
3578 semOutbound = std::make_unique<std::counting_semaphore<>>(std::min(m_max_automatic_outbound, m_max_automatic_connections));
3579 }
3580 if (semAddnode == nullptr) {
3581 // initialize semaphore
3582 semAddnode = std::make_unique<std::counting_semaphore<>>(m_max_addnode);
3583 }
3584
3585 //
3586 // Start threads
3587 //
3588 assert(m_msgproc);
3589 m_interrupt_net->reset();
3590 flagInterruptMsgProc = false;
3591
3592 {
3593 LOCK(mutexMsgProc);
3594 fMsgProcWake = false;
3595 }
3596
3597 // Send and receive from sockets, accept connections
3598 threadSocketHandler = std::thread(&util::TraceThread, "net", [this] { ThreadSocketHandler(); });
3599
3600 if (!gArgs.GetBoolArg("-dnsseed", DEFAULT_DNSSEED))
3601 LogInfo("DNS seeding disabled\n");
3602 else
3603 threadDNSAddressSeed = std::thread(&util::TraceThread, "dnsseed", [this] { ThreadDNSAddressSeed(); });
3604
3605 // Initiate manual connections
3606 threadOpenAddedConnections = std::thread(&util::TraceThread, "addcon", [this] { ThreadOpenAddedConnections(); });
3607
3608 if (connOptions.m_use_addrman_outgoing && !connOptions.m_specified_outgoing.empty()) {
3609 if (m_client_interface) {
3610 m_client_interface->ThreadSafeMessageBox(
3611 _("Cannot provide specific connections and have addrman find outgoing connections at the same time."),
3612 CClientUIInterface::MSG_ERROR);
3613 }
3614 return false;
3615 }
3616 if (connOptions.m_use_addrman_outgoing || !connOptions.m_specified_outgoing.empty()) {
3617 threadOpenConnections = std::thread(
3618 &util::TraceThread, "opencon",
3619 [this, connect = connOptions.m_specified_outgoing, seed_nodes = std::move(seed_nodes)] { ThreadOpenConnections(connect, seed_nodes); });
3620 }
3621
3622 // Process messages
3623 threadMessageHandler = std::thread(&util::TraceThread, "msghand", [this] { ThreadMessageHandler(); });
3624
3625 if (m_i2p_sam_session) {
3626 threadI2PAcceptIncoming =
3627 std::thread(&util::TraceThread, "i2paccept", [this] { ThreadI2PAcceptIncoming(); });
3628 }
3629
3630 if (gArgs.GetBoolArg("-privatebroadcast", DEFAULT_PRIVATE_BROADCAST)) {
3631 threadPrivateBroadcast =
3632 std::thread(&util::TraceThread, "privbcast", [this] { ThreadPrivateBroadcast(); });
3633 }
3634
3635 // Dump network addresses
3636 scheduler.scheduleEvery([this] { DumpAddresses(); }, DUMP_PEERS_INTERVAL);
3637
3638 // Run the ASMap Health check once and then schedule it to run every 24h.
3639 if (m_netgroupman.UsingASMap()) {
3640 ASMapHealthCheck();
3641 scheduler.scheduleEvery([this] { ASMapHealthCheck(); }, ASMAP_HEALTH_CHECK_INTERVAL);
3642 }
3643
3644 return true;
3645 }
3646
3647 class CNetCleanup
3648 {
3649 public:
3650 CNetCleanup() = default;
3651
3652 ~CNetCleanup()
3653 {
3654 #ifdef WIN32
3655 // Shutdown Windows Sockets
3656 WSACleanup();
3657 #endif
3658 }
3659 };
3660 static CNetCleanup instance_of_cnetcleanup;
3661
3662 void CConnman::Interrupt()
3663 {
3664 {
3665 LOCK(mutexMsgProc);
3666 flagInterruptMsgProc = true;
3667 }
3668 condMsgProc.notify_all();
3669
3670 (*m_interrupt_net)();
3671 g_socks5_interrupt();
3672
3673 if (semOutbound) {
3674 for (int i=0; i<m_max_automatic_outbound; i++) {
3675 semOutbound->release();
3676 }
3677 }
3678
3679 if (semAddnode) {
3680 for (int i=0; i<m_max_addnode; i++) {
3681 semAddnode->release();
3682 }
3683 }
3684
3685 m_private_broadcast.m_sem_conn_max.release();
3686 m_private_broadcast.NumToOpenAdd(1); // Just unblock NumToOpenWait() to be able to continue with shutdown.
3687 }
3688
3689 void CConnman::StopThreads()
3690 {
3691 if (threadPrivateBroadcast.joinable()) {
3692 threadPrivateBroadcast.join();
3693 }
3694 if (threadI2PAcceptIncoming.joinable()) {
3695 threadI2PAcceptIncoming.join();
3696 }
3697 if (threadMessageHandler.joinable())
3698 threadMessageHandler.join();
3699 if (threadOpenConnections.joinable())
3700 threadOpenConnections.join();
3701 if (threadOpenAddedConnections.joinable())
3702 threadOpenAddedConnections.join();
3703 if (threadDNSAddressSeed.joinable())
3704 threadDNSAddressSeed.join();
3705 if (threadSocketHandler.joinable())
3706 threadSocketHandler.join();
3707 }
3708
3709 void CConnman::StopNodes()
3710 {
3711 AssertLockNotHeld(m_nodes_mutex);
3712 AssertLockNotHeld(m_reconnections_mutex);
3713
3714 if (fAddressesInitialized) {
3715 DumpAddresses();
3716 fAddressesInitialized = false;
3717
3718 if (m_use_addrman_outgoing) {
3719 // Anchor connections are only dumped during clean shutdown.
3720 std::vector<CAddress> anchors_to_dump = GetCurrentBlockRelayOnlyConns();
3721 if (anchors_to_dump.size() > MAX_BLOCK_RELAY_ONLY_ANCHORS) {
3722 anchors_to_dump.resize(MAX_BLOCK_RELAY_ONLY_ANCHORS);
3723 }
3724 DumpAnchors(gArgs.GetDataDirNet() / ANCHORS_DATABASE_FILENAME, anchors_to_dump);
3725 }
3726 }
3727
3728 // Delete peer connections.
3729 std::vector<CNode*> nodes;
3730 WITH_LOCK(m_nodes_mutex, nodes.swap(m_nodes));
3731 for (CNode* pnode : nodes) {
3732 LogDebug(BCLog::NET, "Stopping node, %s", pnode->DisconnectMsg());
3733 pnode->CloseSocketDisconnect();
3734 DeleteNode(pnode);
3735 }
3736
3737 for (CNode* pnode : m_nodes_disconnected) {
3738 DeleteNode(pnode);
3739 }
3740 m_nodes_disconnected.clear();
3741 WITH_LOCK(m_reconnections_mutex, m_reconnections.clear());
3742 vhListenSocket.clear();
3743 semOutbound.reset();
3744 semAddnode.reset();
3745 }
3746
3747 void CConnman::DeleteNode(CNode* pnode)
3748 {
3749 assert(pnode);
3750 m_msgproc->FinalizeNode(*pnode);
3751 delete pnode;
3752 }
3753
3754 CConnman::~CConnman()
3755 {
3756 Interrupt();
3757 Stop();
3758 }
3759
3760 std::vector<CAddress> CConnman::GetAddressesUnsafe(size_t max_addresses, size_t max_pct, std::optional<Network> network, const bool filtered) const
3761 {
3762 std::vector<CAddress> addresses = addrman.get().GetAddr(max_addresses, max_pct, network, filtered);
3763 if (m_banman) {
3764 addresses.erase(std::remove_if(addresses.begin(), addresses.end(),
3765 [this](const CAddress& addr){return m_banman->IsDiscouraged(addr) || m_banman->IsBanned(addr);}),
3766 addresses.end());
3767 }
3768 return addresses;
3769 }
3770
3771 std::vector<CAddress> CConnman::GetAddresses(CNode& requestor, size_t max_addresses, size_t max_pct)
3772 {
3773 uint64_t network_id = requestor.m_network_key;
3774 const auto current_time = GetTime<std::chrono::microseconds>();
3775 auto r = m_addr_response_caches.emplace(network_id, CachedAddrResponse{});
3776 CachedAddrResponse& cache_entry = r.first->second;
3777 if (cache_entry.m_cache_entry_expiration < current_time) { // If emplace() added new one it has expiration 0.
3778 cache_entry.m_addrs_response_cache = GetAddressesUnsafe(max_addresses, max_pct, /*network=*/std::nullopt);
3779 // Choosing a proper cache lifetime is a trade-off between the privacy leak minimization
3780 // and the usefulness of ADDR responses to honest users.
3781 //
3782 // Longer cache lifetime makes it more difficult for an attacker to scrape
3783 // enough AddrMan data to maliciously infer something useful.
3784 // By the time an attacker scraped enough AddrMan records, most of
3785 // the records should be old enough to not leak topology info by
3786 // e.g. analyzing real-time changes in timestamps.
3787 //
3788 // It takes only several hundred requests to scrape everything from an AddrMan containing 100,000 nodes,
3789 // so ~24 hours of cache lifetime indeed makes the data less inferable by the time
3790 // most of it could be scraped (considering that timestamps are updated via
3791 // ADDR self-announcements and when nodes communicate).
3792 // We also should be robust to those attacks which may not require scraping *full* victim's AddrMan
3793 // (because even several timestamps of the same handful of nodes may leak privacy).
3794 //
3795 // On the other hand, longer cache lifetime makes ADDR responses
3796 // outdated and less useful for an honest requestor, e.g. if most nodes
3797 // in the ADDR response are no longer active.
3798 //
3799 // However, the churn in the network is known to be rather low. Since we consider
3800 // nodes to be "terrible" (see IsTerrible()) if the timestamps are older than 30 days,
3801 // max. 24 hours of "penalty" due to cache shouldn't make any meaningful difference
3802 // in terms of the freshness of the response.
3803 cache_entry.m_cache_entry_expiration = current_time +
3804 21h + FastRandomContext().randrange<std::chrono::microseconds>(6h);
3805 }
3806 return cache_entry.m_addrs_response_cache;
3807 }
3808
3809 bool CConnman::AddNode(const AddedNodeParams& add)
3810 {
3811 const CService resolved(LookupNumeric(add.m_added_node, GetDefaultPort(add.m_added_node)));
3812 const bool resolved_is_valid{resolved.IsValid()};
3813
3814 LOCK(m_added_nodes_mutex);
3815 for (const auto& it : m_added_node_params) {
3816 if (add.m_added_node == it.m_added_node || (resolved_is_valid && resolved == LookupNumeric(it.m_added_node, GetDefaultPort(it.m_added_node)))) return false;
3817 }
3818
3819 m_added_node_params.push_back(add);
3820 return true;
3821 }
3822
3823 bool CConnman::RemoveAddedNode(std::string_view node)
3824 {
3825 LOCK(m_added_nodes_mutex);
3826 for (auto it = m_added_node_params.begin(); it != m_added_node_params.end(); ++it) {
3827 if (node == it->m_added_node) {
3828 m_added_node_params.erase(it);
3829 return true;
3830 }
3831 }
3832 return false;
3833 }
3834
3835 bool CConnman::AddedNodesContain(const CAddress& addr) const
3836 {
3837 AssertLockNotHeld(m_added_nodes_mutex);
3838 const std::string addr_str{addr.ToStringAddr()};
3839 const std::string addr_port_str{addr.ToStringAddrPort()};
3840 LOCK(m_added_nodes_mutex);
3841 return (m_added_node_params.size() < 24 // bound the query to a reasonable limit
3842 && std::any_of(m_added_node_params.cbegin(), m_added_node_params.cend(),
3843 [&](const auto& p) { return p.m_added_node == addr_str || p.m_added_node == addr_port_str; }));
3844 }
3845
3846 size_t CConnman::GetNodeCount(ConnectionDirection flags) const
3847 {
3848 LOCK(m_nodes_mutex);
3849 if (flags == ConnectionDirection::Both) // Shortcut if we want total
3850 return m_nodes.size();
3851
3852 int nNum = 0;
3853 for (const auto& pnode : m_nodes) {
3854 if (flags & (pnode->IsInboundConn() ? ConnectionDirection::In : ConnectionDirection::Out)) {
3855 nNum++;
3856 }
3857 }
3858
3859 return nNum;
3860 }
3861
3862
3863 std::map<CNetAddr, LocalServiceInfo> CConnman::getNetLocalAddresses() const
3864 {
3865 LOCK(g_maplocalhost_mutex);
3866 return mapLocalHost;
3867 }
3868
3869 uint32_t CConnman::GetMappedAS(const CNetAddr& addr) const
3870 {
3871 return m_netgroupman.GetMappedAS(addr);
3872 }
3873
3874 void CConnman::GetNodeStats(std::vector<CNodeStats>& vstats) const
3875 {
3876 AssertLockNotHeld(m_nodes_mutex);
3877
3878 vstats.clear();
3879 LOCK(m_nodes_mutex);
3880 vstats.reserve(m_nodes.size());
3881 for (CNode* pnode : m_nodes) {
3882 vstats.emplace_back();
3883 pnode->CopyStats(vstats.back());
3884 vstats.back().m_mapped_as = GetMappedAS(pnode->addr);
3885 }
3886 }
3887
3888 bool CConnman::DisconnectNode(std::string_view strNode)
3889 {
3890 LOCK(m_nodes_mutex);
3891 auto it = std::ranges::find_if(m_nodes, [&strNode](CNode* node) { return node->m_addr_name == strNode; });
3892 if (it != m_nodes.end()) {
3893 CNode* node{*it};
3894 LogDebug(BCLog::NET, "disconnect by address%s match, %s", (fLogIPs ? strprintf("=%s", strNode) : ""), node->DisconnectMsg());
3895 node->fDisconnect = true;
3896 return true;
3897 }
3898 return false;
3899 }
3900
3901 bool CConnman::DisconnectNode(const CSubNet& subnet)
3902 {
3903 AssertLockNotHeld(m_nodes_mutex);
3904 bool disconnected = false;
3905 LOCK(m_nodes_mutex);
3906 for (CNode* pnode : m_nodes) {
3907 if (subnet.Match(pnode->addr)) {
3908 LogDebug(BCLog::NET, "disconnect by subnet%s match, %s", (fLogIPs ? strprintf("=%s", subnet.ToString()) : ""), pnode->DisconnectMsg());
3909 pnode->fDisconnect = true;
3910 disconnected = true;
3911 }
3912 }
3913 return disconnected;
3914 }
3915
3916 bool CConnman::DisconnectNode(const CNetAddr& addr)
3917 {
3918 AssertLockNotHeld(m_nodes_mutex);
3919 return DisconnectNode(CSubNet(addr));
3920 }
3921
3922 bool CConnman::DisconnectNode(NodeId id)
3923 {
3924 LOCK(m_nodes_mutex);
3925 for(CNode* pnode : m_nodes) {
3926 if (id == pnode->GetId()) {
3927 LogDebug(BCLog::NET, "disconnect by id, %s", pnode->DisconnectMsg());
3928 pnode->fDisconnect = true;
3929 return true;
3930 }
3931 }
3932 return false;
3933 }
3934
3935 void CConnman::RecordBytesRecv(uint64_t bytes)
3936 {
3937 nTotalBytesRecv += bytes;
3938 }
3939
3940 void CConnman::RecordBytesSent(uint64_t bytes)
3941 {
3942 AssertLockNotHeld(m_total_bytes_sent_mutex);
3943 LOCK(m_total_bytes_sent_mutex);
3944
3945 nTotalBytesSent += bytes;
3946
3947 const auto now = GetTime<std::chrono::seconds>();
3948 if (nMaxOutboundCycleStartTime + MAX_UPLOAD_TIMEFRAME < now)
3949 {
3950 // timeframe expired, reset cycle
3951 nMaxOutboundCycleStartTime = now;
3952 nMaxOutboundTotalBytesSentInCycle = 0;
3953 }
3954
3955 nMaxOutboundTotalBytesSentInCycle += bytes;
3956 }
3957
3958 uint64_t CConnman::GetMaxOutboundTarget() const
3959 {
3960 AssertLockNotHeld(m_total_bytes_sent_mutex);
3961 LOCK(m_total_bytes_sent_mutex);
3962 return nMaxOutboundLimit;
3963 }
3964
3965 std::chrono::seconds CConnman::GetMaxOutboundTimeframe() const
3966 {
3967 return MAX_UPLOAD_TIMEFRAME;
3968 }
3969
3970 std::chrono::seconds CConnman::GetMaxOutboundTimeLeftInCycle() const
3971 {
3972 AssertLockNotHeld(m_total_bytes_sent_mutex);
3973 LOCK(m_total_bytes_sent_mutex);
3974 return GetMaxOutboundTimeLeftInCycle_();
3975 }
3976
3977 std::chrono::seconds CConnman::GetMaxOutboundTimeLeftInCycle_() const
3978 {
3979 AssertLockHeld(m_total_bytes_sent_mutex);
3980
3981 if (nMaxOutboundLimit == 0)
3982 return 0s;
3983
3984 if (nMaxOutboundCycleStartTime.count() == 0)
3985 return MAX_UPLOAD_TIMEFRAME;
3986
3987 const std::chrono::seconds cycleEndTime = nMaxOutboundCycleStartTime + MAX_UPLOAD_TIMEFRAME;
3988 const auto now = GetTime<std::chrono::seconds>();
3989 return (cycleEndTime < now) ? 0s : cycleEndTime - now;
3990 }
3991
3992 bool CConnman::OutboundTargetReached(bool historicalBlockServingLimit) const
3993 {
3994 AssertLockNotHeld(m_total_bytes_sent_mutex);
3995 LOCK(m_total_bytes_sent_mutex);
3996 if (nMaxOutboundLimit == 0)
3997 return false;
3998
3999 if (historicalBlockServingLimit)
4000 {
4001 // keep a large enough buffer to at least relay each block once
4002 const std::chrono::seconds timeLeftInCycle = GetMaxOutboundTimeLeftInCycle_();
4003 const uint64_t buffer = timeLeftInCycle / std::chrono::minutes{10} * MAX_BLOCK_SERIALIZED_SIZE;
4004 if (buffer >= nMaxOutboundLimit || nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit - buffer)
4005 return true;
4006 }
4007 else if (nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit)
4008 return true;
4009
4010 return false;
4011 }
4012
4013 uint64_t CConnman::GetOutboundTargetBytesLeft() const
4014 {
4015 AssertLockNotHeld(m_total_bytes_sent_mutex);
4016 LOCK(m_total_bytes_sent_mutex);
4017 if (nMaxOutboundLimit == 0)
4018 return 0;
4019
4020 return (nMaxOutboundTotalBytesSentInCycle >= nMaxOutboundLimit) ? 0 : nMaxOutboundLimit - nMaxOutboundTotalBytesSentInCycle;
4021 }
4022
4023 uint64_t CConnman::GetTotalBytesRecv() const
4024 {
4025 return nTotalBytesRecv;
4026 }
4027
4028 uint64_t CConnman::GetTotalBytesSent() const
4029 {
4030 AssertLockNotHeld(m_total_bytes_sent_mutex);
4031 LOCK(m_total_bytes_sent_mutex);
4032 return nTotalBytesSent;
4033 }
4034
4035 ServiceFlags CConnman::GetLocalServices() const
4036 {
4037 return m_local_services;
4038 }
4039
4040 static std::unique_ptr<Transport> MakeTransport(NodeId id, bool use_v2transport, bool inbound) noexcept
4041 {
4042 if (use_v2transport) {
4043 return std::make_unique<V2Transport>(id, /*initiating=*/!inbound);
4044 } else {
4045 return std::make_unique<V1Transport>(id);
4046 }
4047 }
4048
4049 CNode::CNode(NodeId idIn,
4050 std::shared_ptr<Sock> sock,
4051 const CAddress& addrIn,
4052 uint64_t nKeyedNetGroupIn,
4053 uint64_t nLocalHostNonceIn,
4054 const CService& addrBindIn,
4055 const std::string& addrNameIn,
4056 ConnectionType conn_type_in,
4057 bool inbound_onion,
4058 uint64_t network_key,
4059 CNodeOptions&& node_opts)
4060 : m_transport{MakeTransport(idIn, node_opts.use_v2transport, conn_type_in == ConnectionType::INBOUND)},
4061 m_permission_flags{node_opts.permission_flags},
4062 m_sock{sock},
4063 m_connected{NodeClock::now()},
4064 m_proxy_override{std::move(node_opts.proxy_override)},
4065 addr{addrIn},
4066 addrBind{addrBindIn},
4067 m_addr_name{addrNameIn.empty() ? addr.ToStringAddrPort() : addrNameIn},
4068 m_dest(addrNameIn),
4069 m_inbound_onion{inbound_onion},
4070 m_prefer_evict{node_opts.prefer_evict},
4071 nKeyedNetGroup{nKeyedNetGroupIn},
4072 m_network_key{network_key},
4073 m_conn_type{conn_type_in},
4074 id{idIn},
4075 nLocalHostNonce{nLocalHostNonceIn},
4076 m_recv_flood_size{node_opts.recv_flood_size},
4077 m_i2p_sam_session{std::move(node_opts.i2p_sam_session)}
4078 {
4079 if (inbound_onion) assert(conn_type_in == ConnectionType::INBOUND);
4080
4081 for (const auto& msg : ALL_NET_MESSAGE_TYPES) {
4082 mapRecvBytesPerMsgType[msg] = 0;
4083 }
4084 mapRecvBytesPerMsgType[NET_MESSAGE_TYPE_OTHER] = 0;
4085
4086 if (fLogIPs) {
4087 LogDebug(BCLog::NET, "Added connection to %s peer=%d\n", m_addr_name, id);
4088 } else {
4089 LogDebug(BCLog::NET, "Added connection peer=%d\n", id);
4090 }
4091 }
4092
4093 void CNode::MarkReceivedMsgsForProcessing()
4094 {
4095 AssertLockNotHeld(m_msg_process_queue_mutex);
4096
4097 size_t nSizeAdded = 0;
4098 for (const auto& msg : vRecvMsg) {
4099 // vRecvMsg contains only completed CNetMessage
4100 // the single possible partially deserialized message are held by TransportDeserializer
4101 nSizeAdded += msg.GetMemoryUsage();
4102 }
4103
4104 LOCK(m_msg_process_queue_mutex);
4105 m_msg_process_queue.splice(m_msg_process_queue.end(), vRecvMsg);
4106 m_msg_process_queue_size += nSizeAdded;
4107 fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
4108 }
4109
4110 std::optional<std::pair<CNetMessage, bool>> CNode::PollMessage()
4111 {
4112 LOCK(m_msg_process_queue_mutex);
4113 if (m_msg_process_queue.empty()) return std::nullopt;
4114
4115 std::list<CNetMessage> msgs;
4116 // Just take one message
4117 msgs.splice(msgs.begin(), m_msg_process_queue, m_msg_process_queue.begin());
4118 m_msg_process_queue_size -= msgs.front().GetMemoryUsage();
4119 fPauseRecv = m_msg_process_queue_size > m_recv_flood_size;
4120
4121 return std::make_pair(std::move(msgs.front()), !m_msg_process_queue.empty());
4122 }
4123
4124 bool CConnman::NodeFullyConnected(const CNode* pnode)
4125 {
4126 return pnode && pnode->fSuccessfullyConnected && !pnode->fDisconnect;
4127 }
4128
4129 /// Private broadcast connections only need to send certain message types.
4130 /// Other messages are not needed and may degrade privacy.
4131 static bool IsOutboundMessageAllowedInPrivateBroadcast(std::string_view type) noexcept
4132 {
4133 return type == NetMsgType::VERSION ||
4134 type == NetMsgType::VERACK ||
4135 type == NetMsgType::INV ||
4136 type == NetMsgType::TX ||
4137 type == NetMsgType::PING;
4138 }
4139
4140 void CConnman::PushMessage(CNode* pnode, CSerializedNetMsg&& msg)
4141 {
4142 AssertLockNotHeld(m_total_bytes_sent_mutex);
4143
4144 if (pnode->IsPrivateBroadcastConn() && !IsOutboundMessageAllowedInPrivateBroadcast(msg.m_type)) {
4145 LogDebug(BCLog::PRIVBROADCAST, "Omitting send of message '%s', %s", msg.m_type, pnode->LogPeer());
4146 return;
4147 }
4148
4149 if (!m_private_broadcast.m_outbound_tor_ok_at_least_once.load() && !pnode->IsInboundConn() &&
4150 pnode->addr.IsTor() && msg.m_type == NetMsgType::VERACK) {
4151 // If we are sending the peer VERACK that means we successfully sent
4152 // and received another message to/from that peer (VERSION).
4153 m_private_broadcast.m_outbound_tor_ok_at_least_once.store(true);
4154 }
4155
4156 size_t nMessageSize = msg.data.size();
4157 LogDebug(BCLog::NET, "sending %s (%d bytes) peer=%d\n", msg.m_type, nMessageSize, pnode->GetId());
4158 if (m_capture_messages) {
4159 CaptureMessage(pnode->addr, msg.m_type, msg.data, /*is_incoming=*/false);
4160 }
4161
4162 TRACEPOINT(net, outbound_message,
4163 pnode->GetId(),
4164 pnode->m_addr_name.c_str(),
4165 pnode->ConnectionTypeAsString().c_str(),
4166 msg.m_type.c_str(),
4167 msg.data.size(),
4168 msg.data.data()
4169 );
4170
4171 size_t nBytesSent = 0;
4172 {
4173 LOCK(pnode->cs_vSend);
4174 // Check if the transport still has unsent bytes, and indicate to it that we're about to
4175 // give it a message to send.
4176 const auto& [to_send, more, _msg_type] =
4177 pnode->m_transport->GetBytesToSend(/*have_next_message=*/true);
4178 const bool queue_was_empty{to_send.empty() && pnode->vSendMsg.empty()};
4179
4180 // Update memory usage of send buffer.
4181 pnode->m_send_memusage += msg.GetMemoryUsage();
4182 if (pnode->m_send_memusage + pnode->m_transport->GetSendMemoryUsage() > nSendBufferMaxSize) pnode->fPauseSend = true;
4183 // Move message to vSendMsg queue.
4184 pnode->vSendMsg.push_back(std::move(msg));
4185
4186 // If there was nothing to send before, and there is now (predicted by the "more" value
4187 // returned by the GetBytesToSend call above), attempt "optimistic write":
4188 // because the poll/select loop may pause for SELECT_TIMEOUT_MILLISECONDS before actually
4189 // doing a send, try sending from the calling thread if the queue was empty before.
4190 // With a V1Transport, more will always be true here, because adding a message always
4191 // results in sendable bytes there, but with V2Transport this is not the case (it may
4192 // still be in the handshake).
4193 if (queue_was_empty && more) {
4194 std::tie(nBytesSent, std::ignore) = SocketSendData(*pnode);
4195 }
4196 }
4197 if (nBytesSent) RecordBytesSent(nBytesSent);
4198 }
4199
4200 bool CConnman::ForNode(NodeId id, std::function<bool(CNode* pnode)> func)
4201 {
4202 AssertLockNotHeld(m_nodes_mutex);
4203
4204 CNode* found = nullptr;
4205 LOCK(m_nodes_mutex);
4206 for (auto&& pnode : m_nodes) {
4207 if(pnode->GetId() == id) {
4208 found = pnode;
4209 break;
4210 }
4211 }
4212 return found != nullptr && NodeFullyConnected(found) && func(found);
4213 }
4214
4215 CSipHasher CConnman::GetDeterministicRandomizer(uint64_t id) const
4216 {
4217 return CSipHasher(nSeed0, nSeed1).Write(id);
4218 }
4219
4220 uint64_t CConnman::CalculateKeyedNetGroup(const CNetAddr& address) const
4221 {
4222 std::vector<unsigned char> vchNetGroup(m_netgroupman.GetGroup(address));
4223
4224 return GetDeterministicRandomizer(RANDOMIZER_ID_NETGROUP).Write(vchNetGroup).Finalize();
4225 }
4226
4227 void CConnman::PerformReconnections()
4228 {
4229 AssertLockNotHeld(m_nodes_mutex);
4230 AssertLockNotHeld(m_reconnections_mutex);
4231 AssertLockNotHeld(m_unused_i2p_sessions_mutex);
4232 while (true) {
4233 // Move first element of m_reconnections to todo (avoiding an allocation inside the lock).
4234 decltype(m_reconnections) todo;
4235 {
4236 LOCK(m_reconnections_mutex);
4237 if (m_reconnections.empty()) break;
4238 todo.splice(todo.end(), m_reconnections, m_reconnections.begin());
4239 }
4240
4241 auto& item = *todo.begin();
4242 OpenNetworkConnection(item.addr_connect,
4243 // We only reconnect if the first attempt to connect succeeded at
4244 // connection time, but then failed after the CNode object was
4245 // created. Since we already know connecting is possible, do not
4246 // count failure to reconnect.
4247 /*fCountFailure=*/false,
4248 std::move(item.grant),
4249 item.destination.empty() ? nullptr : item.destination.c_str(),
4250 item.conn_type,
4251 item.use_v2transport,
4252 item.proxy_override);
4253 }
4254 }
4255
4256 void CConnman::ASMapHealthCheck()
4257 {
4258 const std::vector<CAddress> v4_addrs{GetAddressesUnsafe(/*max_addresses=*/0, /*max_pct=*/0, Network::NET_IPV4, /*filtered=*/false)};
4259 const std::vector<CAddress> v6_addrs{GetAddressesUnsafe(/*max_addresses=*/0, /*max_pct=*/0, Network::NET_IPV6, /*filtered=*/false)};
4260 std::vector<CNetAddr> clearnet_addrs;
4261 clearnet_addrs.reserve(v4_addrs.size() + v6_addrs.size());
4262 std::transform(v4_addrs.begin(), v4_addrs.end(), std::back_inserter(clearnet_addrs),
4263 [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
4264 std::transform(v6_addrs.begin(), v6_addrs.end(), std::back_inserter(clearnet_addrs),
4265 [](const CAddress& addr) { return static_cast<CNetAddr>(addr); });
4266 m_netgroupman.ASMapHealthCheck(clearnet_addrs);
4267 }
4268
4269 // Dump binary message to file, with timestamp.
4270 static void CaptureMessageToFile(const CAddress& addr,
4271 const std::string& msg_type,
4272 std::span<const unsigned char> data,
4273 bool is_incoming)
4274 {
4275 // Note: This function captures the message at the time of processing,
4276 // not at socket receive/send time.
4277 // This ensures that the messages are always in order from an application
4278 // layer (processing) perspective.
4279 auto now = GetTime<std::chrono::microseconds>();
4280
4281 // Windows folder names cannot include a colon
4282 std::string clean_addr = addr.ToStringAddrPort();
4283 std::replace(clean_addr.begin(), clean_addr.end(), ':', '_');
4284
4285 fs::path base_path = gArgs.GetDataDirNet() / "message_capture" / fs::u8path(clean_addr);
4286 fs::create_directories(base_path);
4287
4288 fs::path path = base_path / (is_incoming ? "msgs_recv.dat" : "msgs_sent.dat");
4289 AutoFile f{fsbridge::fopen(path, "ab")};
4290
4291 ser_writedata64(f, now.count());
4292 f << std::span{msg_type};
4293 for (auto i = msg_type.length(); i < CMessageHeader::MESSAGE_TYPE_SIZE; ++i) {
4294 f << uint8_t{'\0'};
4295 }
4296 uint32_t size = data.size();
4297 ser_writedata32(f, size);
4298 f << data;
4299
4300 if (f.fclose() != 0) {
4301 throw std::ios_base::failure(
4302 strprintf("Error closing %s after write, file contents are likely incomplete", fs::PathToString(path)));
4303 }
4304 }
4305
4306 std::function<void(const CAddress& addr,
4307 const std::string& msg_type,
4308 std::span<const unsigned char> data,
4309 bool is_incoming)>
4310 CaptureMessage = CaptureMessageToFile;
4311