text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2015 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #ifndef BITCOIN_NET_H
  #define BITCOIN_NET_H
  
  #include "addrdb.h"
  #include "addrman.h"
  #include "bloom.h"
  #include "compat.h"
  #include "limitedmap.h"
  #include "netaddress.h"
  #include "protocol.h"
  #include "random.h"
  #include "streams.h"
  #include "sync.h"
  #include "uint256.h"
  #include "util.h"
  #include "threadinterrupt.h"
  
  #include <atomic>
  #include <deque>
  #include <stdint.h>
  #include <thread>
  #include <memory>
  #include <condition_variable>
  
  #ifndef WIN32
  #include <arpa/inet.h>
  #endif
  
  #include <boost/filesystem/path.hpp>
  #include <boost/foreach.hpp>
  #include <boost/signals2/signal.hpp>
  
  class CAddrMan;
  class CScheduler;
  class CNode;
  
  namespace boost {
      class thread_group;
  } // namespace boost
  
  /** Time between pings automatically sent out for latency probing and keepalive (in seconds). */
  static const int PING_INTERVAL = 2 * 60;
  /** Time after which to disconnect, after waiting for a ping response (or inactivity). */
  static const int TIMEOUT_INTERVAL = 20 * 60;
  /** Minimum time between warnings printed to log. */
  static const int WARNING_INTERVAL = 10 * 60;
  /** Run the feeler connection loop once every 2 minutes or 120 seconds. **/
  static const int FEELER_INTERVAL = 120;
  /** The maximum number of entries in an 'inv' protocol message */
  static const unsigned int MAX_INV_SZ = 50000;
  /** The maximum number of new addresses to accumulate before announcing. */
  static const unsigned int MAX_ADDR_TO_SEND = 1000;
  /** Maximum length of incoming protocol messages (no message over 3 MiB is currently acceptable). */
  static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 3 * 1024 * 1024;
  /** Maximum length of strSubVer in `version` message */
  static const unsigned int MAX_SUBVERSION_LENGTH = 256;
  /** Maximum number of outgoing nodes */
  static const int MAX_OUTBOUND_CONNECTIONS = 8;
  /** Maximum number if outgoing masternodes */
  static const int MAX_OUTBOUND_MASTERNODE_CONNECTIONS = 20;
  /** -listen default */
  static const bool DEFAULT_LISTEN = true;
  /** -upnp default */
  #ifdef USE_UPNP
  static const bool DEFAULT_UPNP = USE_UPNP;
  #else
  static const bool DEFAULT_UPNP = false;
  #endif
  /** The maximum number of entries in mapAskFor */
  static const size_t MAPASKFOR_MAX_SZ = MAX_INV_SZ;
  /** The maximum number of entries in setAskFor (larger due to getdata latency)*/
  static const size_t SETASKFOR_MAX_SZ = 2 * MAX_INV_SZ;
  /** The maximum number of peer connections to maintain. */
  static const unsigned int DEFAULT_MAX_PEER_CONNECTIONS = 125;
  /** The default for -maxuploadtarget. 0 = Unlimited */
  static const uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
  /** Default for blocks only*/
  static const bool DEFAULT_BLOCKSONLY = false;
  
  static const bool DEFAULT_FORCEDNSSEED = false;
  static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
  static const size_t DEFAULT_MAXSENDBUFFER    = 1 * 1000;
  
  static const ServiceFlags REQUIRED_SERVICES = NODE_NETWORK;
  
  // NOTE: When adjusting this, update rpcnet:setban's help ("24h")
  static const unsigned int DEFAULT_MISBEHAVING_BANTIME = 5 * 60;  // Default 5 min ban
  
  typedef int NodeId;
  
  struct AddedNodeInfo
  {
      std::string strAddedNode;
      CService resolvedAddress;
      bool fConnected;
      bool fInbound;
  };
  
  class CTransaction;
  class CNodeStats;
  class CClientUIInterface;
  
  class CConnman
  {
  public:
  
      enum NumConnections {
          CONNECTIONS_NONE = 0,
          CONNECTIONS_IN = (1U << 0),
          CONNECTIONS_OUT = (1U << 1),
          CONNECTIONS_ALL = (CONNECTIONS_IN | CONNECTIONS_OUT),
      };
  
      struct Options
      {
          ServiceFlags nLocalServices = NODE_NONE;
          ServiceFlags nRelevantServices = NODE_NONE;
          int nMaxConnections = 0;
          int nMaxOutbound = 0;
          int nMaxFeeler = 0;
          int nBestHeight = 0;
          CClientUIInterface* uiInterface = nullptr;
          unsigned int nSendBufferMaxSize = 0;
          unsigned int nReceiveFloodSize = 0;
      };
      CConnman();
      ~CConnman();
      bool Start(CScheduler& scheduler, std::string& strNodeError, Options options);
      void Stop();
      void Interrupt();
      bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
      bool GetNetworkActive() const { return fNetworkActive; };
      void SetNetworkActive(bool active);
      bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false, bool fFeeler = false);
      bool CheckIncomingNonce(uint64_t nonce);
  
      // fConnectToMasternode should be 'true' only if you want this node to allow to connect to itself
      // and/or you want it to be disconnected on CMasternodeMan::ProcessMasternodeConnections()
      // Unfortunately, can't make this method private like in Bitcoin,
      // because it's used in many Curve-specific places (masternode, privatesend).
      CNode* ConnectNode(CAddress addrConnect, const char *pszDest = NULL, bool fConnectToMasternode = false);
  
      struct CFullyConnectedOnly {
          bool operator() (const CNode* pnode) const {
              return NodeFullyConnected(pnode);
          }
      };
  
      constexpr static const CFullyConnectedOnly FullyConnectedOnly{};
  
      struct CAllNodes {
          bool operator() (const CNode*) const {return true;}
      };
  
      constexpr static const CAllNodes AllNodes{};
  
      bool ForNode(NodeId id, std::function<bool(const CNode* pnode)> cond, std::function<bool(CNode* pnode)> func);
      bool ForNode(const CService& addr, std::function<bool(const CNode* pnode)> cond, std::function<bool(CNode* pnode)> func);
  
      template<typename Callable>
      bool ForNode(const CService& addr, Callable&& func)
      {
          return ForNode(addr, FullyConnectedOnly, func);
      }
  
      template<typename Callable>
      bool ForNode(NodeId id, Callable&& func)
      {
          return ForNode(id, FullyConnectedOnly, func);
      }
  
      template <typename... Args>
      void PushMessageWithVersionAndFlag(CNode* pnode, int nVersion, int flag, const std::string& sCommand, Args&&... args)
      {
          auto msg(BeginMessage(pnode, nVersion, flag, sCommand));
          ::SerializeMany(msg, msg.nType, msg.nVersion, std::forward<Args>(args)...);
          EndMessage(msg);
          PushMessage(pnode, msg, sCommand);
      }
  
      template <typename... Args>
      void PushMessageWithFlag(CNode* pnode, int flag, const std::string& sCommand, Args&&... args)
      {
          PushMessageWithVersionAndFlag(pnode, 0, flag, sCommand, std::forward<Args>(args)...);
      }
  
      template <typename... Args>
      void PushMessageWithVersion(CNode* pnode, int nVersion, const std::string& sCommand, Args&&... args)
      {
          PushMessageWithVersionAndFlag(pnode, nVersion, 0, sCommand, std::forward<Args>(args)...);
      }
  
      template <typename... Args>
      void PushMessage(CNode* pnode, const std::string& sCommand, Args&&... args)
      {
          PushMessageWithVersionAndFlag(pnode, 0, 0, sCommand, std::forward<Args>(args)...);
      }
  
      template<typename Condition, typename Callable>
      bool ForEachNodeContinueIf(const Condition& cond, Callable&& func)
      {
          LOCK(cs_vNodes);
          for (auto&& node : vNodes)
              if (cond(node))
                  if(!func(node))
                      return false;
          return true;
      };
  
      template<typename Callable>
      bool ForEachNodeContinueIf(Callable&& func)
      {
          return ForEachNodeContinueIf(FullyConnectedOnly, func);
      }
  
      template<typename Condition, typename Callable>
      bool ForEachNodeContinueIf(const Condition& cond, Callable&& func) const
      {
          LOCK(cs_vNodes);
          for (const auto& node : vNodes)
              if (cond(node))
                  if(!func(node))
                      return false;
          return true;
      };
  
      template<typename Callable>
      bool ForEachNodeContinueIf(Callable&& func) const
      {
          return ForEachNodeContinueIf(FullyConnectedOnly, func);
      }
  
      template<typename Condition, typename Callable>
      void ForEachNode(const Condition& cond, Callable&& func)
      {
          LOCK(cs_vNodes);
          for (auto&& node : vNodes) {
              if (cond(node))
                  func(node);
          }
      };
  
      template<typename Callable>
      void ForEachNode(Callable&& func)
      {
          ForEachNode(FullyConnectedOnly, func);
      }
  
      template<typename Condition, typename Callable>
      void ForEachNode(const Condition& cond, Callable&& func) const
      {
          LOCK(cs_vNodes);
          for (auto&& node : vNodes) {
              if (cond(node))
                  func(node);
          }
      };
  
      template<typename Callable>
      void ForEachNode(Callable&& func) const
      {
          ForEachNode(FullyConnectedOnly, func);
      }
  
      template<typename Condition, typename Callable, typename CallableAfter>
      void ForEachNodeThen(const Condition& cond, Callable&& pre, CallableAfter&& post)
      {
          LOCK(cs_vNodes);
          for (auto&& node : vNodes) {
              if (cond(node))
                  pre(node);
          }
          post();
      };
  
      template<typename Callable, typename CallableAfter>
      void ForEachNodeThen(Callable&& pre, CallableAfter&& post)
      {
          ForEachNodeThen(FullyConnectedOnly, pre, post);
      }
  
      template<typename Condition, typename Callable, typename CallableAfter>
      void ForEachNodeThen(const Condition& cond, Callable&& pre, CallableAfter&& post) const
      {
          LOCK(cs_vNodes);
          for (auto&& node : vNodes) {
              if (cond(node))
                  pre(node);
          }
          post();
      };
  
      template<typename Callable, typename CallableAfter>
      void ForEachNodeThen(Callable&& pre, CallableAfter&& post) const
      {
          ForEachNodeThen(FullyConnectedOnly, pre, post);
      }
  
      std::vector<CNode*> CopyNodeVector();
      void ReleaseNodeVector(const std::vector<CNode*>& vecNodes);
  
      void RelayTransaction(const CTransaction& tx);
      void RelayTransaction(const CTransaction& tx, const CDataStream& ss);
      void RelayInv(CInv &inv, const int minProtoVersion = MIN_PEER_PROTO_VERSION);
  
      // Addrman functions
      size_t GetAddressCount() const;
      void SetServices(const CService &addr, ServiceFlags nServices);
      void MarkAddressGood(const CAddress& addr);
      void AddNewAddress(const CAddress& addr, const CAddress& addrFrom, int64_t nTimePenalty = 0);
      void AddNewAddresses(const std::vector<CAddress>& vAddr, const CAddress& addrFrom, int64_t nTimePenalty = 0);
      std::vector<CAddress> GetAddresses();
      void AddressCurrentlyConnected(const CService& addr);
  
      // Denial-of-service detection/prevention
      // The idea is to detect peers that are behaving
      // badly and disconnect/ban them, but do it in a
      // one-coding-mistake-won't-shatter-the-entire-network
      // way.
      // IMPORTANT:  There should be nothing I can give a
      // node that it will forward on that will make that
      // node's peers drop it. If there is, an attacker
      // can isolate a node and/or try to split the network.
      // Dropping a node for sending stuff that is invalid
      // now but might be valid in a later version is also
      // dangerous, because it can cause a network split
      // between nodes running old code and nodes running
      // new code.
      void Ban(const CNetAddr& netAddr, const BanReason& reason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
      void Ban(const CSubNet& subNet, const BanReason& reason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
      void ClearBanned(); // needed for unit testing
      bool IsBanned(CNetAddr ip);
      bool IsBanned(CSubNet subnet);
      bool Unban(const CNetAddr &ip);
      bool Unban(const CSubNet &ip);
      void GetBanned(banmap_t &banmap);
      void SetBanned(const banmap_t &banmap);
  
      void AddOneShot(const std::string& strDest);
  
      bool AddNode(const std::string& node);
      bool RemoveAddedNode(const std::string& node);
      std::vector<AddedNodeInfo> GetAddedNodeInfo();
  
      size_t GetNodeCount(NumConnections num);
      void GetNodeStats(std::vector<CNodeStats>& vstats);
      bool DisconnectNode(const std::string& node);
      bool DisconnectNode(NodeId id);
  
      unsigned int GetSendBufferSize() const;
  
      void AddWhitelistedRange(const CSubNet &subnet);
  
      ServiceFlags GetLocalServices() const;
  
      //!set the max outbound target in bytes
      void SetMaxOutboundTarget(uint64_t limit);
      uint64_t GetMaxOutboundTarget();
  
      //!set the timeframe for the max outbound target
      void SetMaxOutboundTimeframe(uint64_t timeframe);
      uint64_t GetMaxOutboundTimeframe();
  
      //!check if the outbound target is reached
      // if param historicalBlockServingLimit is set true, the function will
      // response true if the limit for serving historical blocks has been reached
      bool OutboundTargetReached(bool historicalBlockServingLimit);
  
      //!response the bytes left in the current max outbound cycle
      // in case of no limit, it will always response 0
      uint64_t GetOutboundTargetBytesLeft();
  
      //!response the time in second left in the current max outbound cycle
      // in case of no limit, it will always response 0
      uint64_t GetMaxOutboundTimeLeftInCycle();
  
      uint64_t GetTotalBytesRecv();
      uint64_t GetTotalBytesSent();
  
      void SetBestHeight(int height);
      int GetBestHeight() const;
  
  
      unsigned int GetReceiveFloodSize() const;
  private:
      struct ListenSocket {
          SOCKET socket;
          bool whitelisted;
  
          ListenSocket(SOCKET socket_, bool whitelisted_) : socket(socket_), whitelisted(whitelisted_) {}
      };
  
      void ThreadOpenAddedConnections();
      void ProcessOneShot();
      void ThreadOpenConnections();
      void ThreadMessageHandler();
      void AcceptConnection(const ListenSocket& hListenSocket);
      void ThreadSocketHandler();
      void ThreadDNSAddressSeed();
      void ThreadMnbRequestConnections();
  
      void WakeMessageHandler();
  
      CNode* FindNode(const CNetAddr& ip);
      CNode* FindNode(const CSubNet& subNet);
      CNode* FindNode(const std::string& addrName);
      CNode* FindNode(const CService& addr);
  
      bool AttemptToEvictConnection();
      bool IsWhitelistedRange(const CNetAddr &addr);
  
      void DeleteNode(CNode* pnode);
  
      NodeId GetNewNodeId();
  
      size_t SocketSendData(CNode *pnode);
      //!check is the banlist has unwritten changes
      bool BannedSetIsDirty();
      //!set the "dirty" flag for the banlist
      void SetBannedSetDirty(bool dirty=true);
      //!clean unused entries (if bantime has expired)
      void SweepBanned();
      void DumpAddresses();
      void DumpData();
      void DumpBanlist();
  
      CDataStream BeginMessage(CNode* node, int nVersion, int flags, const std::string& sCommand);
      void PushMessage(CNode* pnode, CDataStream& strm, const std::string& sCommand);
      void EndMessage(CDataStream& strm);
  
      // Network stats
      void RecordBytesRecv(uint64_t bytes);
      void RecordBytesSent(uint64_t bytes);
  
      // Whether the node should be passed out in ForEach* callbacks
      static bool NodeFullyConnected(const CNode* pnode);
  
      // Network usage totals
      CCriticalSection cs_totalBytesRecv;
      CCriticalSection cs_totalBytesSent;
      uint64_t nTotalBytesRecv;
      uint64_t nTotalBytesSent;
  
      // outbound limit & stats
      uint64_t nMaxOutboundTotalBytesSentInCycle;
      uint64_t nMaxOutboundCycleStartTime;
      uint64_t nMaxOutboundLimit;
      uint64_t nMaxOutboundTimeframe;
  
      // Whitelisted ranges. Any node connecting from these is automatically
      // whitelisted (as well as those connecting to whitelisted binds).
      std::vector<CSubNet> vWhitelistedRange;
      CCriticalSection cs_vWhitelistedRange;
  
      unsigned int nSendBufferMaxSize;
      unsigned int nReceiveFloodSize;
  
      std::vector<ListenSocket> vhListenSocket;
      bool fNetworkActive;
      banmap_t setBanned;
      CCriticalSection cs_setBanned;
      bool setBannedIsDirty;
      bool fAddressesInitialized;
      CAddrMan addrman;
      std::deque<std::string> vOneShots;
      CCriticalSection cs_vOneShots;
      std::vector<std::string> vAddedNodes;
      CCriticalSection cs_vAddedNodes;
      std::vector<CNode*> vNodes;
      std::list<CNode*> vNodesDisconnected;
      mutable CCriticalSection cs_vNodes;
      std::atomic<NodeId> nLastNodeId;
  
      /** Services this instance offers */
      ServiceFlags nLocalServices;
  
      /** Services this instance cares about */
      ServiceFlags nRelevantServices;
  
      CSemaphore *semOutbound;
      CSemaphore *semMasternodeOutbound;
      int nMaxConnections;
      int nMaxOutbound;
      int nMaxFeeler;
      std::atomic<int> nBestHeight;
      CClientUIInterface* clientInterface;
  
      /** flag for waking the message processor. */
      bool fMsgProcWake;
  
      std::condition_variable condMsgProc;
      std::mutex mutexMsgProc;
      std::atomic<bool> flagInterruptMsgProc;
  
      CThreadInterrupt interruptNet;
  
      std::thread threadDNSAddressSeed;
      std::thread threadSocketHandler;
      std::thread threadOpenAddedConnections;
      std::thread threadOpenConnections;
      std::thread threadMnbRequestConnections;
      std::thread threadMessageHandler;
  };
  extern std::unique_ptr<CConnman> g_connman;
  void Discover(boost::thread_group& threadGroup);
  void MapPort(bool fUseUPnP);
  unsigned short GetListenPort();
  bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
  
  struct CombinerAll
  {
      typedef bool result_type;
  
      template<typename I>
      bool operator()(I first, I last) const
      {
          while (first != last) {
              if (!(*first)) return false;
              ++first;
          }
          return true;
      }
  };
  
  // Signals for message handling
  struct CNodeSignals
  {
      boost::signals2::signal<bool (CNode*, CConnman&, std::atomic<bool>&), CombinerAll> ProcessMessages;
      boost::signals2::signal<bool (CNode*, CConnman&, std::atomic<bool>&), CombinerAll> SendMessages;
      boost::signals2::signal<void (CNode*, CConnman&)> InitializeNode;
      boost::signals2::signal<void (NodeId, bool&)> FinalizeNode;
  };
  
  
  CNodeSignals& GetNodeSignals();
  
  
  enum
  {
      LOCAL_NONE,   // unknown
      LOCAL_IF,     // address a local interface listens on
      LOCAL_BIND,   // address explicit bound to
      LOCAL_UPNP,   // address reported by UPnP
      LOCAL_MANUAL, // address explicitly specified (-externalip=)
  
      LOCAL_MAX
  };
  
  bool IsPeerAddrLocalGood(CNode *pnode);
  void AdvertiseLocal(CNode *pnode);
  void SetLimited(enum Network net, bool fLimited = true);
  bool IsLimited(enum Network net);
  bool IsLimited(const CNetAddr& addr);
  bool AddLocal(const CService& addr, int nScore = LOCAL_NONE);
  bool AddLocal(const CNetAddr& addr, int nScore = LOCAL_NONE);
  bool RemoveLocal(const CService& addr);
  bool SeenLocal(const CService& addr);
  bool IsLocal(const CService& addr);
  bool GetLocal(CService &addr, const CNetAddr *paddrPeer = NULL);
  bool IsReachable(enum Network net);
  bool IsReachable(const CNetAddr &addr);
  CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices);
  
  
  extern bool fDiscover;
  extern bool fListen;
  extern bool fRelayTxes;
  
  extern std::map<CInv, CDataStream> mapRelay;
  extern std::deque<std::pair<int64_t, CInv> > vRelayExpiration;
  extern CCriticalSection cs_mapRelay;
  extern limitedmap<uint256, int64_t> mapAlreadyAskedFor;
  
  /** Subversion as sent to the P2P network in `version` messages */
  extern std::string strSubVersion;
  
  struct LocalServiceInfo {
      int nScore;
      int nPort;
  };
  
  extern CCriticalSection cs_mapLocalHost;
  extern std::map<CNetAddr, LocalServiceInfo> mapLocalHost;
  typedef std::map<std::string, uint64_t> mapMsgCmdSize; //command, total bytes
  
  class CNodeStats
  {
  public:
      NodeId nodeid;
      ServiceFlags nServices;
      bool fRelayTxes;
      int64_t nLastSend;
      int64_t nLastRecv;
      int64_t nTimeConnected;
      int64_t nTimeOffset;
      std::string addrName;
      int nVersion;
      std::string cleanSubVer;
      bool fInbound;
      int nStartingHeight;
      uint64_t nSendBytes;
      mapMsgCmdSize mapSendBytesPerMsgCmd;
      uint64_t nRecvBytes;
      mapMsgCmdSize mapRecvBytesPerMsgCmd;
      bool fWhitelisted;
      double dPingTime;
      double dPingWait;
      double dMinPing;
      std::string addrLocal;
      CAddress addr;
  };
  
  
  
  
  class CNetMessage {
  public:
      bool in_data;                   // parsing header (false) or data (true)
  
      CDataStream hdrbuf;             // partially received header
      CMessageHeader hdr;             // complete header
      unsigned int nHdrPos;
  
      CDataStream vRecv;              // received message data
      unsigned int nDataPos;
  
      int64_t nTime;                  // time (in microseconds) of message receipt.
  
      CNetMessage(const CMessageHeader::MessageStartChars& pchMessageStartIn, int nTypeIn, int nVersionIn) : hdrbuf(nTypeIn, nVersionIn), hdr(pchMessageStartIn), vRecv(nTypeIn, nVersionIn) {
          hdrbuf.resize(24);
          in_data = false;
          nHdrPos = 0;
          nDataPos = 0;
          nTime = 0;
      }
  
      bool complete() const
      {
          if (!in_data)
              return false;
          return (hdr.nMessageSize == nDataPos);
      }
  
      void SetVersion(int nVersionIn)
      {
          hdrbuf.SetVersion(nVersionIn);
          vRecv.SetVersion(nVersionIn);
      }
  
      int readHeader(const char *pch, unsigned int nBytes);
      int readData(const char *pch, unsigned int nBytes);
  };
  
  
  /** Information about a peer */
  class CNode
  {
      friend class CConnman;
  public:
      // socket
      ServiceFlags nServices;
      ServiceFlags nServicesExpected;
      SOCKET hSocket;
      size_t nSendSize; // total size of all vSendMsg entries
      size_t nSendOffset; // offset inside the first vSendMsg already sent
      uint64_t nSendBytes;
      std::deque<CSerializeData> vSendMsg;
      CCriticalSection cs_vSend;
  
      CCriticalSection cs_vProcessMsg;
      std::list<CNetMessage> vProcessMsg;
      size_t nProcessQueueSize;
  
      std::deque<CInv> vRecvGetData;
      uint64_t nRecvBytes;
      std::atomic<int> nRecvVersion;
  
      int64_t nLastSend;
      int64_t nLastRecv;
      int64_t nTimeConnected;
      int64_t nTimeOffset;
      int64_t nLastWarningTime;
      CAddress addr;
      std::string addrName;
      CService addrLocal;
      int nNumWarningsSkipped;
      std::atomic<int> nVersion;
      // strSubVer is whatever byte array we read from the wire. However, this field is intended
      // to be printed out, displayed to humans in various forms and so on. So we sanitize it and
      // store the sanitized version in cleanSubVer. The original should be used when dealing with
      // the network or wire types and the cleaned string used when displayed or logged.
      std::string strSubVer, cleanSubVer;
      bool fWhitelisted; // This peer can bypass DoS banning.
      bool fFeeler; // If true this node is being used as a short lived feeler.
      bool fOneShot;
      bool fClient;
      bool fInbound;
      bool fNetworkNode;
      std::atomic_bool fSuccessfullyConnected;
      bool fDisconnect;
      // We use fRelayTxes for two purposes -
      // a) it allows us to not relay tx invs before receiving the peer's version message
      // b) the peer may tell us in its version message that we should not relay tx invs
      //    unless it loads a bloom filter.
      bool fRelayTxes;
      // If 'true' this node will be disconnected on CMasternodeMan::ProcessMasternodeConnections()
      bool fMasternode;
      CSemaphoreGrant grantOutbound;
      CSemaphoreGrant grantMasternodeOutbound;
      CCriticalSection cs_filter;
      CBloomFilter* pfilter;
      int nRefCount;
      NodeId id;
  
      std::atomic_bool fPauseRecv;
      std::atomic_bool fPauseSend;
  protected:
  
      mapMsgCmdSize mapSendBytesPerMsgCmd;
      mapMsgCmdSize mapRecvBytesPerMsgCmd;
  
  public:
      uint256 hashContinue;
      int nStartingHeight;
  
      // flood relay
      std::vector<CAddress> vAddrToSend;
      CRollingBloomFilter addrKnown;
      bool fGetAddr;
      std::set<uint256> setKnown;
      int64_t nNextAddrSend;
      int64_t nNextLocalAddrSend;
  
      // inventory based relay
      CRollingBloomFilter filterInventoryKnown;
      std::vector<CInv> vInventoryToSend;
      CCriticalSection cs_inventory;
      std::set<uint256> setAskFor;
      std::multimap<int64_t, CInv> mapAskFor;
      int64_t nNextInvSend;
      // Used for headers announcements - unfiltered blocks to relay
      // Also protected by cs_inventory
      std::vector<uint256> vBlockHashesToAnnounce;
      // Blocks received by INV while headers chain was too far behind. These are used to delay GETHEADERS messages
      // Also protected by cs_inventory
      std::vector<uint256> vBlockHashesFromINV;
  
      // Block and TXN accept times
      std::atomic<int64_t> nLastBlockTime;
      std::atomic<int64_t> nLastTXTime;
  
      // Ping time measurement:
      // The pong reply we're expecting, or 0 if no pong expected.
      uint64_t nPingNonceSent;
      // Time (in usec) the last ping was sent, or 0 if no ping was ever sent.
      int64_t nPingUsecStart;
      // Last measured round-trip time.
      int64_t nPingUsecTime;
      // Best measured round-trip time.
      int64_t nMinPingUsecTime;
      // Whether a ping is requested.
      bool fPingQueued;
  
      std::vector<unsigned char> vchKeyedNetGroup;
  
      CNode(NodeId id, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn, SOCKET hSocketIn, const CAddress &addrIn, const std::string &addrNameIn = "", bool fInboundIn = false, bool fNetworkNodeIn = false);
      ~CNode();
  
  private:
      // Secret key for computing keyed net groups
      static std::vector<unsigned char> vchSecretKey;
  
      CCriticalSection cs_nRefCount;
  
      CNode(const CNode&);
      void operator=(const CNode&);
  
      uint64_t nLocalHostNonce;
      ServiceFlags nLocalServices;
      int nMyStartingHeight;
      int nSendVersion;
      std::list<CNetMessage> vRecvMsg;  // Used only by SocketHandler thread
  public:
  
      NodeId GetId() const {
        return id;
      }
  
      uint64_t GetLocalNonce() const {
        return nLocalHostNonce;
      }
  
      int GetMyStartingHeight() const {
        return nMyStartingHeight;
      }
  
      int GetRefCount()
      {
          LOCK(cs_nRefCount);
          assert(nRefCount >= 0);
          return nRefCount;
      }
  
      bool ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete);
  
      void SetRecvVersion(int nVersionIn)
      {
          nRecvVersion = nVersionIn;
      }
      int GetRecvVersion()
      {
          return nRecvVersion;
      }
      void SetSendVersion(int nVersionIn);
      int GetSendVersion() const;
  
      CNode* AddRef()
      {
          LOCK(cs_nRefCount);
          nRefCount++;
          return this;
      }
  
      void Release()
      {
          LOCK(cs_nRefCount);
          nRefCount--;
          assert(nRefCount >= 0);
      }
  
  
  
      void AddAddressKnown(const CAddress& addr)
      {
          addrKnown.insert(addr.GetKey());
      }
  
      void PushAddress(const CAddress& addr)
      {
          // Known checking here is only to save space from duplicates.
          // SendMessages will filter it again for knowns that were added
          // after addresses were pushed.
          if (addr.IsValid() && !addrKnown.contains(addr.GetKey())) {
              if (vAddrToSend.size() >= MAX_ADDR_TO_SEND) {
                  vAddrToSend[insecure_rand() % vAddrToSend.size()] = addr;
              } else {
                  vAddrToSend.push_back(addr);
              }
          }
      }
  
  
      void AddInventoryKnown(const CInv& inv)
      {
          {
              LOCK(cs_inventory);
              filterInventoryKnown.insert(inv.hash);
          }
      }
  
      void PushInventory(const CInv& inv)
      {
          {
              LOCK(cs_inventory);
              if (inv.type == MSG_TX && filterInventoryKnown.contains(inv.hash)) {
                  LogPrint("net", "PushInventory --  filtered inv: %s peer=%d\n", inv.ToString(), id);
                  return;
              }
              LogPrint("net", "PushInventory --  inv: %s peer=%d\n", inv.ToString(), id);
              vInventoryToSend.push_back(inv);
          }
      }
  
      void PushBlockHash(const uint256 &hash)
      {
          LOCK(cs_inventory);
          vBlockHashesToAnnounce.push_back(hash);
      }
  
      void PushBlockHashFromINV(const uint256 &hash)
      {
          LOCK(cs_inventory);
          vBlockHashesFromINV.push_back(hash);
      }
  
      void AskFor(const CInv& inv);
  
      void CloseSocketDisconnect();
  
      void copyStats(CNodeStats &stats);
  
      ServiceFlags GetLocalServices() const
      {
          return nLocalServices;
      }
  
      static std::vector<unsigned char> CalculateKeyedNetGroup(CAddress& address);
  };
  
  class CExplicitNetCleanup
  {
  public:
      static void callCleanup();
  };
  
  
  
  /** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
  int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds);
  
  #endif // BITCOIN_NET_H
  