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 "amount.h"
  #include "bloom.h"
  #include "compat.h"
  #include "limitedmap.h"
  #include "netbase.h"
  #include "protocol.h"
  #include "random.h"
  #include "streams.h"
  #include "sync.h"
  #include "uint256.h"
  
  #include <atomic>
  #include <deque>
  #include <stdint.h>
  
  #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;
  /** 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 4 MB is currently acceptable). */
  static const unsigned int MAX_PROTOCOL_MESSAGE_LENGTH = 4 * 1000 * 1000;
  /** Maximum length of strSubVer in `version` message */
  static const unsigned int MAX_SUBVERSION_LENGTH = 256;
  /** -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 = 60 * 60 * 24;  // Default 24-hour ban
  
  unsigned int ReceiveFloodSize();
  unsigned int SendBufferSize();
  
  typedef int NodeId;
  
  void AddOneShot(const std::string& strDest);
  void AddressCurrentlyConnected(const CService& addr);
  CNode* FindNode(const CNetAddr& ip);
  CNode* FindNode(const CSubNet& subNet);
  CNode* FindNode(const std::string& addrName);
  CNode* FindNode(const CService& ip);
  CNode* FindNode(const NodeId id); //TODO: Remove this
  
  CNode* ConnectNode(CAddress addrConnect, const char *pszDest = NULL, bool fCountFailure = false, bool fConnectToNoirnode = false);
  
  bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false, bool fFeeler = false);
  void MapPort(bool fUseUPnP);
  unsigned short GetListenPort();
  bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);
  void StartNode(boost::thread_group& threadGroup, CScheduler& scheduler);
  bool StopNode();
  void SocketSendData(CNode *pnode);
  
  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<int ()> GetHeight;
      boost::signals2::signal<bool (CNode*), CombinerAll> ProcessMessages;
      boost::signals2::signal<bool (CNode*), CombinerAll> SendMessages;
      boost::signals2::signal<void (NodeId, const CNode*)> InitializeNode;
      boost::signals2::signal<void (NodeId)> 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 = NULL);
  
  
  extern bool fDiscover;
  extern bool fListen;
  extern ServiceFlags nLocalServices;
  extern ServiceFlags nRelevantServices;
  extern bool fRelayTxes;
  extern uint64_t nLocalHostNonce;
  extern CAddrMan addrman;
  
  /** Maximum number of connections to simultaneously allow (aka connection slots) */
  extern int nMaxConnections;
  
  extern std::vector<CNode*> vNodes;
  extern CCriticalSection cs_vNodes;
  extern limitedmap<uint256, int64_t> mapAlreadyAskedFor;
  
  extern std::vector<std::string> vAddedNodes;
  extern CCriticalSection cs_vAddedNodes;
  
  extern NodeId nLastNodeId;
  extern CCriticalSection cs_nLastNodeId;
  
  /** 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 dPingMin;
      std::string addrLocal;
  };
  
  
  
  
  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);
  };
  
  
  typedef enum BanReason
  {
      BanReasonUnknown          = 0,
      BanReasonNodeMisbehaving  = 1,
      BanReasonManuallyAdded    = 2
  } BanReason;
  
  class CBanEntry
  {
  public:
      static const int CURRENT_VERSION=1;
      int nVersion;
      int64_t nCreateTime;
      int64_t nBanUntil;
      uint8_t banReason;
  
      CBanEntry()
      {
          SetNull();
      }
  
      CBanEntry(int64_t nCreateTimeIn)
      {
          SetNull();
          nCreateTime = nCreateTimeIn;
      }
  
      ADD_SERIALIZE_METHODS;
  
      template <typename Stream, typename Operation>
      inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
          READWRITE(this->nVersion);
          nVersion = this->nVersion;
          READWRITE(nCreateTime);
          READWRITE(nBanUntil);
          READWRITE(banReason);
      }
  
      void SetNull()
      {
          nVersion = CBanEntry::CURRENT_VERSION;
          nCreateTime = 0;
          nBanUntil = 0;
          banReason = BanReasonUnknown;
      }
  
      std::string banReasonToString()
      {
          switch (banReason) {
          case BanReasonNodeMisbehaving:
              return "node misbehaving";
          case BanReasonManuallyAdded:
              return "manually added";
          default:
              return "unknown";
          }
      }
  };
  
  typedef std::map<CSubNet, CBanEntry> banmap_t;
  
  /** Information about a peer */
  class CNode
  {
  public:
      // socket
      ServiceFlags nServices;
      ServiceFlags nServicesExpected;
      SOCKET hSocket;
      CDataStream ssSend;
      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;
  
      std::deque<CInv> vRecvGetData;
      std::deque<CNetMessage> vRecvMsg;
      CCriticalSection cs_vRecvMsg;
      uint64_t nRecvBytes;
      int nRecvVersion;
  
      int64_t nLastSend;
      int64_t nLastRecv;
      int64_t nTimeConnected;
      int64_t nTimeOffset;
      const CAddress addr;
      std::string addrName;
      CService addrLocal;
      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;
      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; //protected by cs_filter
      bool fSentAddr;
      CSemaphoreGrant grantOutbound;
      CCriticalSection cs_filter;
      CBloomFilter* pfilter;
      std::atomic<int> nRefCount;
      NodeId id;
      // noirnode from dash
      bool fNoirnode;
  
      const uint64_t nKeyedNetGroup;
  protected:
  
      // Denial-of-service detection/prevention
      // Key is IP address, value is banned-until-time
      static banmap_t setBanned;
      static CCriticalSection cs_setBanned;
      static bool setBannedIsDirty;
  
      // Whitelisted ranges. Any node connecting from these is automatically
      // whitelisted (as well as those connecting to whitelisted binds).
      static std::vector<CSubNet> vWhitelistedRange;
      static CCriticalSection cs_vWhitelistedRange;
  
      mapMsgCmdSize mapSendBytesPerMsgCmd;
      mapMsgCmdSize mapRecvBytesPerMsgCmd;
  
      // Basic fuzz-testing
      void Fuzz(int nChance); // modifies ssSend
  
  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;
      // Set of transaction ids we still have to announce.
      // They are sorted by the mempool before relay, so the order is not important.
      std::set<uint256> setInventoryTxToSend;
      // List of block ids we still have announce.
      // There is no final sorting before sending, as they are always sent immediately
      // and in the order requested.
      std::vector<uint256> vInventoryBlockToSend;
      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;
      // Used for BIP35 mempool sending, also protected by cs_inventory
      bool fSendMempool;
  
      // Last time a "MEMPOOL" request was serviced.
      std::atomic<int64_t> timeLastMempoolReq;
  
      // 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;
      // Minimum fee rate with which to filter inv's to this node
      CAmount minFeeFilter;
      CCriticalSection cs_feeFilter;
      CAmount lastSentFeeFilter;
      int64_t nextSendTimeFeeFilter;
  
      CNode(SOCKET hSocketIn, const CAddress &addrIn, const std::string &addrNameIn = "", bool fInboundIn = false);
  //    CNode(SOCKET hSocketIn, const CAddress &addrIn, const std::string &addrNameIn = "", bool fInboundIn = false, bool fNetworkNodeIn = false);
      ~CNode();
  
  private:
      // Network usage totals
      static CCriticalSection cs_totalBytesRecv;
      static CCriticalSection cs_totalBytesSent;
      static uint64_t nTotalBytesRecv;
      static uint64_t nTotalBytesSent;
  
      // outbound limit & stats
      static uint64_t nMaxOutboundTotalBytesSentInCycle;
      static uint64_t nMaxOutboundCycleStartTime;
      static uint64_t nMaxOutboundLimit;
      static uint64_t nMaxOutboundTimeframe;
  
      CNode(const CNode&);
      void operator=(const CNode&);
  
      static uint64_t CalculateKeyedNetGroup(const CAddress& ad);
  
  public:
  
      NodeId GetId() const {
        return id;
      }
  
      int GetRefCount()
      {
          int rc = nRefCount;
          assert(rc >= 0);
          return rc;
      }
  
      // requires LOCK(cs_vRecvMsg)
      unsigned int GetTotalRecvSize()
      {
          unsigned int total = 0;
          BOOST_FOREACH(const CNetMessage &msg, vRecvMsg)
              total += msg.vRecv.size() + 24;
          return total;
      }
  
      // requires LOCK(cs_vRecvMsg)
      bool ReceiveMsgBytes(const char *pch, unsigned int nBytes);
  
      // requires LOCK(cs_vRecvMsg)
      void SetRecvVersion(int nVersionIn)
      {
          nRecvVersion = nVersionIn;
          BOOST_FOREACH(CNetMessage &msg, vRecvMsg)
              msg.SetVersion(nVersionIn);
      }
  
      CNode* AddRef()
      {
          ++nRefCount;
          return this;
      }
  
      void Release()
      {
          --nRefCount;
      }
  
  
  
      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) {
              if (!filterInventoryKnown.contains(inv.hash)) {
                  setInventoryTxToSend.insert(inv.hash);
              }
          } else if (inv.type == MSG_BLOCK) {
              vInventoryBlockToSend.push_back(inv.hash);
          } else {
              vInventoryToSend.push_back(inv);
          }
      }
  
      void PushBlockHash(const uint256 &hash)
      {
          LOCK(cs_inventory);
          vBlockHashesToAnnounce.push_back(hash);
      }
  
      void AskFor(const CInv& inv);
  
      // TODO: Document the postcondition of this function.  Is cs_vSend locked?
      void BeginMessage(const char* pszCommand) EXCLUSIVE_LOCK_FUNCTION(cs_vSend);
  
      // TODO: Document the precondition of this function.  Is cs_vSend locked?
      void AbortMessage() UNLOCK_FUNCTION(cs_vSend);
  
      // TODO: Document the precondition of this function.  Is cs_vSend locked?
      void EndMessage(const char* pszCommand) UNLOCK_FUNCTION(cs_vSend);
  
      void PushVersion();
  
  
      void PushMessage(const char* pszCommand)
      {
          try
          {
              BeginMessage(pszCommand);
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1>
      void PushMessage(const char* pszCommand, const T1& a1)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      /** Send a message containing a1, serialized with flag flag. */
      template<typename T1>
      void PushMessageWithFlag(int flag, const char* pszCommand, const T1& a1)
      {
          try
          {
              BeginMessage(pszCommand);
              WithOrVersion(&ssSend, flag) << a1;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4, typename T5>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4, const T5& a5)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4 << a5;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4, const T5& a5, const T6& a6)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4 << a5 << a6;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4, const T5& a5, const T6& a6, const T7& a7)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4 << a5 << a6 << a7;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4, const T5& a5, const T6& a6, const T7& a7, const T8& a8)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4 << a5 << a6 << a7 << a8;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      template<typename T1, typename T2, typename T3, typename T4, typename T5, typename T6, typename T7, typename T8, typename T9>
      void PushMessage(const char* pszCommand, const T1& a1, const T2& a2, const T3& a3, const T4& a4, const T5& a5, const T6& a6, const T7& a7, const T8& a8, const T9& a9)
      {
          try
          {
              BeginMessage(pszCommand);
              ssSend << a1 << a2 << a3 << a4 << a5 << a6 << a7 << a8 << a9;
              EndMessage(pszCommand);
          }
          catch (...)
          {
              AbortMessage();
              throw;
          }
      }
  
      void CloseSocketDisconnect();
  
      // 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.
      static void ClearBanned(); // needed for unit testing
      static bool IsBanned(CNetAddr ip);
      static bool IsBanned(CSubNet subnet);
      static void Ban(const CNetAddr &ip, const BanReason &banReason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
      static void Ban(const CSubNet &subNet, const BanReason &banReason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
      static bool Unban(const CNetAddr &ip);
      static bool Unban(const CSubNet &ip);
      static void GetBanned(banmap_t &banmap);
      static void SetBanned(const banmap_t &banmap);
  
      //!check is the banlist has unwritten changes
      static bool BannedSetIsDirty();
      //!set the "dirty" flag for the banlist
      static void SetBannedSetDirty(bool dirty=true);
      //!clean unused entries (if bantime has expired)
      static void SweepBanned();
  
      void copyStats(CNodeStats &stats);
  
      static bool IsWhitelistedRange(const CNetAddr &ip);
      static void AddWhitelistedRange(const CSubNet &subnet);
  
      // Network stats
      static void RecordBytesRecv(uint64_t bytes);
      static void RecordBytesSent(uint64_t bytes);
  
      static uint64_t GetTotalBytesRecv();
      static uint64_t GetTotalBytesSent();
  
      //!set the max outbound target in bytes
      static void SetMaxOutboundTarget(uint64_t limit);
      static uint64_t GetMaxOutboundTarget();
  
      //!set the timeframe for the max outbound target
      static void SetMaxOutboundTimeframe(uint64_t timeframe);
      static 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
      static bool OutboundTargetReached(bool historicalBlockServingLimit);
  
      //!response the bytes left in the current max outbound cycle
      // in case of no limit, it will always response 0
      static 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
      static uint64_t GetMaxOutboundTimeLeftInCycle();
  };
  
  
  
  class CTransaction;
  void RelayTransaction(const CTransaction& tx);
  void RelayInv(CInv &inv, const int minProtoVersion = MIN_PEER_PROTO_VERSION);
  
  /** Access to the (IP) address database (peers.dat) */
  class CAddrDB
  {
  private:
      boost::filesystem::path pathAddr;
  public:
      CAddrDB();
      bool Write(const CAddrMan& addr);
      bool Read(CAddrMan& addr);
      bool Read(CAddrMan& addr, CDataStream& ssPeers);
  };
  
  /** Access to the banlist database (banlist.dat) */
  class CBanDB
  {
  private:
      boost::filesystem::path pathBanlist;
  public:
      CBanDB();
      bool Write(const banmap_t& banSet);
      bool Read(banmap_t& banSet);
  };
  
  /** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
  int64_t PoissonNextSend(int64_t nNow, int average_interval_seconds);
  
  struct AddedNodeInfo
  {
      std::string strAddedNode;
      CService resolvedAddress;
      bool fConnected;
      bool fInbound;
  };
  
  std::vector<CNode*> CopyNodeVector();
  void ReleaseNodeVector(const std::vector<CNode*>& vecNodes);
  
  std::vector<AddedNodeInfo> GetAddedNodeInfo();
  
  #endif // BITCOIN_NET_H
  