src/net.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2015 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 #ifndef BITCOIN_NET_H
   7 #define BITCOIN_NET_H
   8
   9 #include "addrdb.h"
  10 #include "addrman.h"
  11 #include "amount.h"
  12 #include "bloom.h"
  13 #include "compat.h"
  14 #include "hash.h"
  15 #include "limitedmap.h"
  16 #include "netaddress.h"
  17 #include "protocol.h"
  18 #include "random.h"
  19 #include "streams.h"
  20 #include "sync.h"
  21 #include "uint256.h"
  22 #include "threadinterrupt.h"
  23
  24 #include <atomic>
  25 #include <deque>
  26 #include <stdint.h>
  27 #include <thread>
  28 #include <memory>
  29 #include <condition_variable>
  30
  31 #ifndef WIN32
  32 #include <arpa/inet.h>
  33 #endif
  34
  35 #include <boost/filesystem/path.hpp>
  36 #include <boost/foreach.hpp>
  37 #include <boost/signals2/signal.hpp>
  38
  39 class CAddrMan;
  40 class CScheduler;
  41 class CNode;
  42
  43 namespace boost {
  44     class thread_group;
  45 } // namespace boost
  46
  47 /** Time between pings automatically sent out for latency probing and keepalive (in seconds). */
  48 static const int PING_INTERVAL = 2 * 60;
  49 /** Time after which to disconnect, after waiting for a ping response (or inactivity). */
  50 static const int TIMEOUT_INTERVAL = 20 * 60;
  51 /** Run the feeler connection loop once every 2 minutes or 120 seconds. **/
  52 static const int FEELER_INTERVAL = 120;
  53 /** The maximum number of entries in an 'inv' protocol message */
  54 static const unsigned int MAX_INV_SZ = 50000;
  55 /** The maximum number of new addresses to accumulate before announcing. */
  56 static const unsigned int MAX_ADDR_TO_SEND = 1000;
  57 /** Maximum length of incoming protocol messages (no message over 4 MB is currently acceptable). */
  58 static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 4 * 1000 * 1000;
  59 /** Maximum length of strSubVer in `version` message */
  60 static const unsigned int MAX_SUBVERSION_LENGTH = 256;
  61 /** Maximum number of outgoing nodes */
  62 static const int MAX_OUTBOUND_CONNECTIONS = 8;
  63 /** -listen default */
  64 static const bool DEFAULT_LISTEN = true;
  65 /** -upnp default */
  66 #ifdef USE_UPNP
  67 static const bool DEFAULT_UPNP = USE_UPNP;
  68 #else
  69 static const bool DEFAULT_UPNP = false;
  70 #endif
  71 /** The maximum number of entries in mapAskFor */
  72 static const size_t MAPASKFOR_MAX_SZ = MAX_INV_SZ;
  73 /** The maximum number of entries in setAskFor (larger due to getdata latency)*/
  74 static const size_t SETASKFOR_MAX_SZ = 2 * MAX_INV_SZ;
  75 /** The maximum number of peer connections to maintain. */
  76 static const unsigned int DEFAULT_MAX_PEER_CONNECTIONS = 125;
  77 /** The default for -maxuploadtarget. 0 = Unlimited */
  78 static const uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
  79 /** The default timeframe for -maxuploadtarget. 1 day. */
  80 static const uint64_t MAX_UPLOAD_TIMEFRAME = 60 * 60 * 24;
  81 /** Default for blocks only*/
  82 static const bool DEFAULT_BLOCKSONLY = false;
  83
  84 static const bool DEFAULT_FORCEDNSSEED = false;
  85 static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
  86 static const size_t DEFAULT_MAXSENDBUFFER    = 1 * 1000;
  87
  88 static const ServiceFlags REQUIRED_SERVICES = NODE_NETWORK;
  89
  90 // NOTE: When adjusting this, update rpcnet:setban's help ("24h")
  91 static const unsigned int DEFAULT_MISBEHAVING_BANTIME = 60 * 60 * 24;  // Default 24-hour ban
  92
  93 typedef int NodeId;
  94
  95 struct AddedNodeInfo
  96 {
  97     std::string strAddedNode;
  98     CService resolvedAddress;
  99     bool fConnected;
 100     bool fInbound;
 101 };
 102
 103 class CTransaction;
 104 class CNodeStats;
 105 class CClientUIInterface;
 106
 107 struct CSerializedNetMsg
 108 {
 109     CSerializedNetMsg() = default;
 110     CSerializedNetMsg(CSerializedNetMsg&&) = default;
 111     CSerializedNetMsg& operator=(CSerializedNetMsg&&) = default;
 112     // No copying, only moves.
 113     CSerializedNetMsg(const CSerializedNetMsg& msg) = delete;
 114     CSerializedNetMsg& operator=(const CSerializedNetMsg&) = delete;
 115
 116     std::vector<unsigned char> data;
 117     std::string command;
 118 };
 119
 120
 121 class CConnman
 122 {
 123 public:
 124
 125     enum NumConnections {
 126         CONNECTIONS_NONE = 0,
 127         CONNECTIONS_IN = (1U << 0),
 128         CONNECTIONS_OUT = (1U << 1),
 129         CONNECTIONS_ALL = (CONNECTIONS_IN | CONNECTIONS_OUT),
 130     };
 131
 132     struct Options
 133     {
 134         ServiceFlags nLocalServices = NODE_NONE;
 135         ServiceFlags nRelevantServices = NODE_NONE;
 136         int nMaxConnections = 0;
 137         int nMaxOutbound = 0;
 138         int nMaxFeeler = 0;
 139         int nBestHeight = 0;
 140         CClientUIInterface* uiInterface = nullptr;
 141         unsigned int nSendBufferMaxSize = 0;
 142         unsigned int nReceiveFloodSize = 0;
 143         uint64_t nMaxOutboundTimeframe = 0;
 144         uint64_t nMaxOutboundLimit = 0;
 145     };
 146     CConnman(uint64_t seed0, uint64_t seed1);
 147     ~CConnman();
 148     bool Start(CScheduler& scheduler, std::string& strNodeError, Options options);
 149     void Stop();
 150     void Interrupt();
 151     bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
 152     bool GetNetworkActive() const { return fNetworkActive; };
 153     void SetNetworkActive(bool active);
 154     bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false, bool fFeeler = false);
 155     bool CheckIncomingNonce(uint64_t nonce);
 156
 157     bool ForNode(NodeId id, std::function<bool(CNode* pnode)> func);
 158
 159     void PushMessage(CNode* pnode, CSerializedNetMsg&& msg);
 160
 161     template<typename Callable>
 162     bool ForEachNodeContinueIf(Callable&& func)
 163     {
 164         LOCK(cs_vNodes);
 165         for (auto&& node : vNodes)
 166             if(!func(node))
 167                 return false;
 168         return true;
 169     };
 170
 171     template<typename Callable>
 172     bool ForEachNodeContinueIf(Callable&& func) const
 173     {
 174         LOCK(cs_vNodes);
 175         for (const auto& node : vNodes)
 176             if(!func(node))
 177                 return false;
 178         return true;
 179     };
 180
 181     template<typename Callable, typename CallableAfter>
 182     bool ForEachNodeContinueIfThen(Callable&& pre, CallableAfter&& post)
 183     {
 184         bool ret = true;
 185         LOCK(cs_vNodes);
 186         for (auto&& node : vNodes)
 187             if(!pre(node)) {
 188                 ret = false;
 189                 break;
 190             }
 191         post();
 192         return ret;
 193     };
 194
 195     template<typename Callable, typename CallableAfter>
 196     bool ForEachNodeContinueIfThen(Callable&& pre, CallableAfter&& post) const
 197     {
 198         bool ret = true;
 199         LOCK(cs_vNodes);
 200         for (const auto& node : vNodes)
 201             if(!pre(node)) {
 202                 ret = false;
 203                 break;
 204             }
 205         post();
 206         return ret;
 207     };
 208
 209     template<typename Callable>
 210     void ForEachNode(Callable&& func)
 211     {
 212         LOCK(cs_vNodes);
 213         for (auto&& node : vNodes)
 214             func(node);
 215     };
 216
 217     template<typename Callable>
 218     void ForEachNode(Callable&& func) const
 219     {
 220         LOCK(cs_vNodes);
 221         for (const auto& node : vNodes)
 222             func(node);
 223     };
 224
 225     template<typename Callable, typename CallableAfter>
 226     void ForEachNodeThen(Callable&& pre, CallableAfter&& post)
 227     {
 228         LOCK(cs_vNodes);
 229         for (auto&& node : vNodes)
 230             pre(node);
 231         post();
 232     };
 233
 234     template<typename Callable, typename CallableAfter>
 235     void ForEachNodeThen(Callable&& pre, CallableAfter&& post) const
 236     {
 237         LOCK(cs_vNodes);
 238         for (const auto& node : vNodes)
 239             pre(node);
 240         post();
 241     };
 242
 243     void RelayTransaction(const CTransaction& tx);
 244
 245     // Addrman functions
 246     size_t GetAddressCount() const;
 247     void SetServices(const CService &addr, ServiceFlags nServices);
 248     void MarkAddressGood(const CAddress& addr);
 249     void AddNewAddress(const CAddress& addr, const CAddress& addrFrom, int64_t nTimePenalty = 0);
 250     void AddNewAddresses(const std::vector<CAddress>& vAddr, const CAddress& addrFrom, int64_t nTimePenalty = 0);
 251     std::vector<CAddress> GetAddresses();
 252     void AddressCurrentlyConnected(const CService& addr);
 253
 254     // Denial-of-service detection/prevention
 255     // The idea is to detect peers that are behaving
 256     // badly and disconnect/ban them, but do it in a
 257     // one-coding-mistake-won't-shatter-the-entire-network
 258     // way.
 259     // IMPORTANT:  There should be nothing I can give a
 260     // node that it will forward on that will make that
 261     // node's peers drop it. If there is, an attacker
 262     // can isolate a node and/or try to split the network.
 263     // Dropping a node for sending stuff that is invalid
 264     // now but might be valid in a later version is also
 265     // dangerous, because it can cause a network split
 266     // between nodes running old code and nodes running
 267     // new code.
 268     void Ban(const CNetAddr& netAddr, const BanReason& reason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
 269     void Ban(const CSubNet& subNet, const BanReason& reason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
 270     void ClearBanned(); // needed for unit testing
 271     bool IsBanned(CNetAddr ip);
 272     bool IsBanned(CSubNet subnet);
 273     bool Unban(const CNetAddr &ip);
 274     bool Unban(const CSubNet &ip);
 275     void GetBanned(banmap_t &banmap);
 276     void SetBanned(const banmap_t &banmap);
 277
 278     void AddOneShot(const std::string& strDest);
 279
 280     bool AddNode(const std::string& node);
 281     bool RemoveAddedNode(const std::string& node);
 282     std::vector<AddedNodeInfo> GetAddedNodeInfo();
 283
 284     size_t GetNodeCount(NumConnections num);
 285     void GetNodeStats(std::vector<CNodeStats>& vstats);
 286     bool DisconnectAddress(const CNetAddr& addr);
 287     bool DisconnectNode(const std::string& node);
 288     bool DisconnectNode(NodeId id);
 289     bool DisconnectSubnet(const CSubNet& subnet);
 290
 291     unsigned int GetSendBufferSize() const;
 292
 293     void AddWhitelistedRange(const CSubNet &subnet);
 294
 295     ServiceFlags GetLocalServices() const;
 296
 297     //!set the max outbound target in bytes
 298     void SetMaxOutboundTarget(uint64_t limit);
 299     uint64_t GetMaxOutboundTarget();
 300
 301     //!set the timeframe for the max outbound target
 302     void SetMaxOutboundTimeframe(uint64_t timeframe);
 303     uint64_t GetMaxOutboundTimeframe();
 304
 305     //!check if the outbound target is reached
 306     // if param historicalBlockServingLimit is set true, the function will
 307     // response true if the limit for serving historical blocks has been reached
 308     bool OutboundTargetReached(bool historicalBlockServingLimit);
 309
 310     //!response the bytes left in the current max outbound cycle
 311     // in case of no limit, it will always response 0
 312     uint64_t GetOutboundTargetBytesLeft();
 313
 314     //!response the time in second left in the current max outbound cycle
 315     // in case of no limit, it will always response 0
 316     uint64_t GetMaxOutboundTimeLeftInCycle();
 317
 318     uint64_t GetTotalBytesRecv();
 319     uint64_t GetTotalBytesSent();
 320
 321     void SetBestHeight(int height);
 322     int GetBestHeight() const;
 323
 324     /** Get a unique deterministic randomizer. */
 325     CSipHasher GetDeterministicRandomizer(uint64_t id);
 326
 327 private:
 328     struct ListenSocket {
 329         SOCKET socket;
 330         bool whitelisted;
 331
 332         ListenSocket(SOCKET socket_, bool whitelisted_) : socket(socket_), whitelisted(whitelisted_) {}
 333     };
 334
 335     void ThreadOpenAddedConnections();
 336     void ProcessOneShot();
 337     void ThreadOpenConnections();
 338     void ThreadMessageHandler();
 339     void AcceptConnection(const ListenSocket& hListenSocket);
 340     void ThreadSocketHandler();
 341     void ThreadDNSAddressSeed();
 342
 343     uint64_t CalculateKeyedNetGroup(const CAddress& ad);
 344
 345     CNode* FindNode(const CNetAddr& ip);
 346     CNode* FindNode(const CSubNet& subNet);
 347     CNode* FindNode(const std::string& addrName);
 348     CNode* FindNode(const CService& addr);
 349
 350     bool AttemptToEvictConnection();
 351     CNode* ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure);
 352     bool IsWhitelistedRange(const CNetAddr &addr);
 353
 354     void DeleteNode(CNode* pnode);
 355
 356     NodeId GetNewNodeId();
 357
 358     //!check is the banlist has unwritten changes
 359     bool BannedSetIsDirty();
 360     //!set the "dirty" flag for the banlist
 361     void SetBannedSetDirty(bool dirty=true);
 362     //!clean unused entries (if bantime has expired)
 363     void SweepBanned();
 364     void DumpAddresses();
 365     void DumpData();
 366     void DumpBanlist();
 367
 368     unsigned int GetReceiveFloodSize() const;
 369
 370     // Network stats
 371     void RecordBytesRecv(uint64_t bytes);
 372     void RecordBytesSent(uint64_t bytes);
 373
 374     // Network usage totals
 375     CCriticalSection cs_totalBytesRecv;
 376     CCriticalSection cs_totalBytesSent;
 377     uint64_t nTotalBytesRecv;
 378     uint64_t nTotalBytesSent;
 379
 380     // outbound limit & stats
 381     uint64_t nMaxOutboundTotalBytesSentInCycle;
 382     uint64_t nMaxOutboundCycleStartTime;
 383     uint64_t nMaxOutboundLimit;
 384     uint64_t nMaxOutboundTimeframe;
 385
 386     // Whitelisted ranges. Any node connecting from these is automatically
 387     // whitelisted (as well as those connecting to whitelisted binds).
 388     std::vector<CSubNet> vWhitelistedRange;
 389     CCriticalSection cs_vWhitelistedRange;
 390
 391     unsigned int nSendBufferMaxSize;
 392     unsigned int nReceiveFloodSize;
 393
 394     std::vector<ListenSocket> vhListenSocket;
 395     std::atomic<bool> fNetworkActive;
 396     banmap_t setBanned;
 397     CCriticalSection cs_setBanned;
 398     bool setBannedIsDirty;
 399     bool fAddressesInitialized;
 400     CAddrMan addrman;
 401     std::deque<std::string> vOneShots;
 402     CCriticalSection cs_vOneShots;
 403     std::vector<std::string> vAddedNodes;
 404     CCriticalSection cs_vAddedNodes;
 405     std::vector<CNode*> vNodes;
 406     std::list<CNode*> vNodesDisconnected;
 407     mutable CCriticalSection cs_vNodes;
 408     std::atomic<NodeId> nLastNodeId;
 409
 410     /** Services this instance offers */
 411     ServiceFlags nLocalServices;
 412
 413     /** Services this instance cares about */
 414     ServiceFlags nRelevantServices;
 415
 416     CSemaphore *semOutbound;
 417     int nMaxConnections;
 418     int nMaxOutbound;
 419     int nMaxFeeler;
 420     std::atomic<int> nBestHeight;
 421     CClientUIInterface* clientInterface;
 422
 423     /** SipHasher seeds for deterministic randomness */
 424     const uint64_t nSeed0, nSeed1;
 425
 426     std::condition_variable condMsgProc;
 427     std::mutex mutexMsgProc;
 428     std::atomic<bool> flagInterruptMsgProc;
 429
 430     CThreadInterrupt interruptNet;
 431
 432     std::thread threadDNSAddressSeed;
 433     std::thread threadSocketHandler;
 434     std::thread threadOpenAddedConnections;
 435     std::thread threadOpenConnections;
 436     std::thread threadMessageHandler;
 437 };
 438 extern std::unique_ptr<CConnman> g_connman;
 439 void Discover(boost::thread_group& threadGroup);
 440 void MapPort(bool fUseUPnP);
 441 unsigned short GetListenPort();
 442 bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
 443 size_t SocketSendData(CNode *pnode);
 444
 445 struct CombinerAll
 446 {
 447     typedef bool result_type;
 448
 449     template<typename I>
 450     bool operator()(I first, I last) const
 451     {
 452         while (first != last) {
 453             if (!(*first)) return false;
 454             ++first;
 455         }
 456         return true;
 457     }
 458 };
 459
 460 // Signals for message handling
 461 struct CNodeSignals
 462 {
 463     boost::signals2::signal<bool (CNode*, CConnman&), CombinerAll> ProcessMessages;
 464     boost::signals2::signal<bool (CNode*, CConnman&), CombinerAll> SendMessages;
 465     boost::signals2::signal<void (CNode*, CConnman&)> InitializeNode;
 466     boost::signals2::signal<void (NodeId, bool&)> FinalizeNode;
 467 };
 468
 469
 470 CNodeSignals& GetNodeSignals();
 471
 472
 473 enum
 474 {
 475     LOCAL_NONE,   // unknown
 476     LOCAL_IF,     // address a local interface listens on
 477     LOCAL_BIND,   // address explicit bound to
 478     LOCAL_UPNP,   // address reported by UPnP
 479     LOCAL_MANUAL, // address explicitly specified (-externalip=)
 480
 481     LOCAL_MAX
 482 };
 483
 484 bool IsPeerAddrLocalGood(CNode *pnode);
 485 void AdvertiseLocal(CNode *pnode);
 486 void SetLimited(enum Network net, bool fLimited = true);
 487 bool IsLimited(enum Network net);
 488 bool IsLimited(const CNetAddr& addr);
 489 bool AddLocal(const CService& addr, int nScore = LOCAL_NONE);
 490 bool AddLocal(const CNetAddr& addr, int nScore = LOCAL_NONE);
 491 bool RemoveLocal(const CService& addr);
 492 bool SeenLocal(const CService& addr);
 493 bool IsLocal(const CService& addr);
 494 bool GetLocal(CService &addr, const CNetAddr *paddrPeer = NULL);
 495 bool IsReachable(enum Network net);
 496 bool IsReachable(const CNetAddr &addr);
 497 CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices);
 498
 499
 500 extern bool fDiscover;
 501 extern bool fListen;
 502 extern bool fRelayTxes;
 503
 504 extern limitedmap<uint256, int64_t> mapAlreadyAskedFor;
 505
 506 /** Subversion as sent to the P2P network in `version` messages */
 507 extern std::string strSubVersion;
 508
 509 struct LocalServiceInfo {
 510     int nScore;
 511     int nPort;
 512 };
 513
 514 extern CCriticalSection cs_mapLocalHost;
 515 extern std::map<CNetAddr, LocalServiceInfo> mapLocalHost;
 516 typedef std::map<std::string, uint64_t> mapMsgCmdSize; //command, total bytes
 517
 518 class CNodeStats
 519 {
 520 public:
 521     NodeId nodeid;
 522     ServiceFlags nServices;
 523     bool fRelayTxes;
 524     int64_t nLastSend;
 525     int64_t nLastRecv;
 526     int64_t nTimeConnected;
 527     int64_t nTimeOffset;
 528     std::string addrName;
 529     int nVersion;
 530     std::string cleanSubVer;
 531     bool fInbound;
 532     int nStartingHeight;
 533     uint64_t nSendBytes;
 534     mapMsgCmdSize mapSendBytesPerMsgCmd;
 535     uint64_t nRecvBytes;
 536     mapMsgCmdSize mapRecvBytesPerMsgCmd;
 537     bool fWhitelisted;
 538     double dPingTime;
 539     double dPingWait;
 540     double dMinPing;
 541     std::string addrLocal;
 542     CAddress addr;
 543 };
 544
 545
 546
 547
 548 class CNetMessage {
 549 private:
 550     mutable CHash256 hasher;
 551     mutable uint256 data_hash;
 552 public:
 553     bool in_data;                   // parsing header (false) or data (true)
 554
 555     CDataStream hdrbuf;             // partially received header
 556     CMessageHeader hdr;             // complete header
 557     unsigned int nHdrPos;
 558
 559     CDataStream vRecv;              // received message data
 560     unsigned int nDataPos;
 561
 562     int64_t nTime;                  // time (in microseconds) of message receipt.
 563
 564     CNetMessage(const CMessageHeader::MessageStartChars& pchMessageStartIn, int nTypeIn, int nVersionIn) : hdrbuf(nTypeIn, nVersionIn), hdr(pchMessageStartIn), vRecv(nTypeIn, nVersionIn) {
 565         hdrbuf.resize(24);
 566         in_data = false;
 567         nHdrPos = 0;
 568         nDataPos = 0;
 569         nTime = 0;
 570     }
 571
 572     bool complete() const
 573     {
 574         if (!in_data)
 575             return false;
 576         return (hdr.nMessageSize == nDataPos);
 577     }
 578
 579     const uint256& GetMessageHash() const;
 580
 581     void SetVersion(int nVersionIn)
 582     {
 583         hdrbuf.SetVersion(nVersionIn);
 584         vRecv.SetVersion(nVersionIn);
 585     }
 586
 587     int readHeader(const char *pch, unsigned int nBytes);
 588     int readData(const char *pch, unsigned int nBytes);
 589 };
 590
 591
 592 /** Information about a peer */
 593 class CNode
 594 {
 595     friend class CConnman;
 596 public:
 597     // socket
 598     ServiceFlags nServices;
 599     ServiceFlags nServicesExpected;
 600     SOCKET hSocket;
 601     size_t nSendSize; // total size of all vSendMsg entries
 602     size_t nSendOffset; // offset inside the first vSendMsg already sent
 603     uint64_t nSendBytes;
 604     std::deque<std::vector<unsigned char>> vSendMsg;
 605     CCriticalSection cs_vSend;
 606
 607     std::deque<CInv> vRecvGetData;
 608     std::deque<CNetMessage> vRecvMsg;
 609     CCriticalSection cs_vRecvMsg;
 610     uint64_t nRecvBytes;
 611     int nRecvVersion;
 612
 613     int64_t nLastSend;
 614     int64_t nLastRecv;
 615     int64_t nTimeConnected;
 616     int64_t nTimeOffset;
 617     const CAddress addr;
 618     std::string addrName;
 619     CService addrLocal;
 620     int nVersion;
 621     // strSubVer is whatever byte array we read from the wire. However, this field is intended
 622     // to be printed out, displayed to humans in various forms and so on. So we sanitize it and
 623     // store the sanitized version in cleanSubVer. The original should be used when dealing with
 624     // the network or wire types and the cleaned string used when displayed or logged.
 625     std::string strSubVer, cleanSubVer;
 626     bool fWhitelisted; // This peer can bypass DoS banning.
 627     bool fFeeler; // If true this node is being used as a short lived feeler.
 628     bool fOneShot;
 629     bool fClient;
 630     const bool fInbound;
 631     bool fSuccessfullyConnected;
 632     std::atomic_bool fDisconnect;
 633     // We use fRelayTxes for two purposes -
 634     // a) it allows us to not relay tx invs before receiving the peer's version message
 635     // b) the peer may tell us in its version message that we should not relay tx invs
 636     //    unless it loads a bloom filter.
 637     bool fRelayTxes; //protected by cs_filter
 638     bool fSentAddr;
 639     CSemaphoreGrant grantOutbound;
 640     CCriticalSection cs_filter;
 641     CBloomFilter* pfilter;
 642     int nRefCount;
 643     const NodeId id;
 644
 645     const uint64_t nKeyedNetGroup;
 646 protected:
 647
 648     mapMsgCmdSize mapSendBytesPerMsgCmd;
 649     mapMsgCmdSize mapRecvBytesPerMsgCmd;
 650
 651 public:
 652     uint256 hashContinue;
 653     int nStartingHeight;
 654
 655     // flood relay
 656     std::vector<CAddress> vAddrToSend;
 657     CRollingBloomFilter addrKnown;
 658     bool fGetAddr;
 659     std::set<uint256> setKnown;
 660     int64_t nNextAddrSend;
 661     int64_t nNextLocalAddrSend;
 662
 663     // inventory based relay
 664     CRollingBloomFilter filterInventoryKnown;
 665     // Set of transaction ids we still have to announce.
 666     // They are sorted by the mempool before relay, so the order is not important.
 667     std::set<uint256> setInventoryTxToSend;
 668     // List of block ids we still have announce.
 669     // There is no final sorting before sending, as they are always sent immediately
 670     // and in the order requested.
 671     std::vector<uint256> vInventoryBlockToSend;
 672     CCriticalSection cs_inventory;
 673     std::set<uint256> setAskFor;
 674     std::multimap<int64_t, CInv> mapAskFor;
 675     int64_t nNextInvSend;
 676     // Used for headers announcements - unfiltered blocks to relay
 677     // Also protected by cs_inventory
 678     std::vector<uint256> vBlockHashesToAnnounce;
 679     // Used for BIP35 mempool sending, also protected by cs_inventory
 680     bool fSendMempool;
 681
 682     // Last time a "MEMPOOL" request was serviced.
 683     std::atomic<int64_t> timeLastMempoolReq;
 684
 685     // Block and TXN accept times
 686     std::atomic<int64_t> nLastBlockTime;
 687     std::atomic<int64_t> nLastTXTime;
 688
 689     // Ping time measurement:
 690     // The pong reply we're expecting, or 0 if no pong expected.
 691     uint64_t nPingNonceSent;
 692     // Time (in usec) the last ping was sent, or 0 if no ping was ever sent.
 693     int64_t nPingUsecStart;
 694     // Last measured round-trip time.
 695     int64_t nPingUsecTime;
 696     // Best measured round-trip time.
 697     int64_t nMinPingUsecTime;
 698     // Whether a ping is requested.
 699     bool fPingQueued;
 700     // Minimum fee rate with which to filter inv's to this node
 701     CAmount minFeeFilter;
 702     CCriticalSection cs_feeFilter;
 703     CAmount lastSentFeeFilter;
 704     int64_t nextSendTimeFeeFilter;
 705
 706     CNode(NodeId id, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn, SOCKET hSocketIn, const CAddress &addrIn, uint64_t nKeyedNetGroupIn, uint64_t nLocalHostNonceIn, const std::string &addrNameIn = "", bool fInboundIn = false);
 707     ~CNode();
 708
 709 private:
 710     CNode(const CNode&);
 711     void operator=(const CNode&);
 712
 713
 714     const uint64_t nLocalHostNonce;
 715     // Services offered to this peer
 716     const ServiceFlags nLocalServices;
 717     const int nMyStartingHeight;
 718     int nSendVersion;
 719 public:
 720
 721     NodeId GetId() const {
 722       return id;
 723     }
 724
 725     uint64_t GetLocalNonce() const {
 726       return nLocalHostNonce;
 727     }
 728
 729     int GetMyStartingHeight() const {
 730       return nMyStartingHeight;
 731     }
 732
 733     int GetRefCount()
 734     {
 735         assert(nRefCount >= 0);
 736         return nRefCount;
 737     }
 738
 739     // requires LOCK(cs_vRecvMsg)
 740     unsigned int GetTotalRecvSize()
 741     {
 742         unsigned int total = 0;
 743         BOOST_FOREACH(const CNetMessage &msg, vRecvMsg)
 744             total += msg.vRecv.size() + 24;
 745         return total;
 746     }
 747
 748     // requires LOCK(cs_vRecvMsg)
 749     bool ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete);
 750
 751     // requires LOCK(cs_vRecvMsg)
 752     void SetRecvVersion(int nVersionIn)
 753     {
 754         nRecvVersion = nVersionIn;
 755         BOOST_FOREACH(CNetMessage &msg, vRecvMsg)
 756             msg.SetVersion(nVersionIn);
 757     }
 758     void SetSendVersion(int nVersionIn)
 759     {
 760         // Send version may only be changed in the version message, and
 761         // only one version message is allowed per session. We can therefore
 762         // treat this value as const and even atomic as long as it's only used
 763         // once the handshake is complete. Any attempt to set this twice is an
 764         // error.
 765         assert(nSendVersion == 0);
 766         nSendVersion = nVersionIn;
 767     }
 768
 769     int GetSendVersion() const
 770     {
 771         // The send version should always be explicitly set to
 772         // INIT_PROTO_VERSION rather than using this value until the handshake
 773         // is complete.
 774         assert(nSendVersion != 0);
 775         return nSendVersion;
 776     }
 777
 778     CNode* AddRef()
 779     {
 780         nRefCount++;
 781         return this;
 782     }
 783
 784     void Release()
 785     {
 786         nRefCount--;
 787     }
 788
 789
 790
 791     void AddAddressKnown(const CAddress& _addr)
 792     {
 793         addrKnown.insert(_addr.GetKey());
 794     }
 795
 796     void PushAddress(const CAddress& _addr, FastRandomContext &insecure_rand)
 797     {
 798         // Known checking here is only to save space from duplicates.
 799         // SendMessages will filter it again for knowns that were added
 800         // after addresses were pushed.
 801         if (_addr.IsValid() && !addrKnown.contains(_addr.GetKey())) {
 802             if (vAddrToSend.size() >= MAX_ADDR_TO_SEND) {
 803                 vAddrToSend[insecure_rand.rand32() % vAddrToSend.size()] = _addr;
 804             } else {
 805                 vAddrToSend.push_back(_addr);
 806             }
 807         }
 808     }
 809
 810
 811     void AddInventoryKnown(const CInv& inv)
 812     {
 813         {
 814             LOCK(cs_inventory);
 815             filterInventoryKnown.insert(inv.hash);
 816         }
 817     }
 818
 819     void PushInventory(const CInv& inv)
 820     {
 821         LOCK(cs_inventory);
 822         if (inv.type == MSG_TX) {
 823             if (!filterInventoryKnown.contains(inv.hash)) {
 824                 setInventoryTxToSend.insert(inv.hash);
 825             }
 826         } else if (inv.type == MSG_BLOCK) {
 827             vInventoryBlockToSend.push_back(inv.hash);
 828         }
 829     }
 830
 831     void PushBlockHash(const uint256 &hash)
 832     {
 833         LOCK(cs_inventory);
 834         vBlockHashesToAnnounce.push_back(hash);
 835     }
 836
 837     void AskFor(const CInv& inv);
 838
 839     void CloseSocketDisconnect();
 840
 841     void copyStats(CNodeStats &stats);
 842
 843     ServiceFlags GetLocalServices() const
 844     {
 845         return nLocalServices;
 846     }
 847 };
 848
 849
 850
 851
 852
 853 /** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
 854 int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds);
 855
 856 #endif // BITCOIN_NET_H