text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2018 The Era developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  #ifndef ERA_NET_H
  #define ERA_NET_H
  
  #include <boost/array.hpp>
  #include <boost/foreach.hpp>
  #include <boost/signals2/signal.hpp>
  #include <deque>
  #include <openssl/rand.h>
  
  
  #ifndef WIN32
  #include <arpa/inet.h>
  #endif
  
  #include "addrman.h"
  #include "hash.h"
  #include "mruset.h"
  #include "netbase.h"
  #include "protocol.h"
  
  class CNode;
  class CBlockIndex;
  extern int nBestHeight;
  
  
  /** 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;
  
  inline unsigned int ReceiveFloodSize() { return 1000 * GetArg("-maxreceivebuffer", 5 * 1000); }
  inline unsigned int SendBufferSize() { return 1000 * GetArg("-maxsendbuffer", 1 * 1000); }
  
  void AddOneShot(std::string strDest);
  bool RecvLine(SOCKET hSocket, std::string& strLine);
  void AddressCurrentlyConnected(const CService& addr);
  CNode* FindNode(const CNetAddr& ip);
  CNode* FindNode(const std::string& addrName);
  CNode* FindNode(const CService& ip);
  CNode* ConnectNode(CAddress addrConnect, const char* strDest = NULL);
  void MapPort(bool fUseUPnP);
  unsigned short GetListenPort();
  bool BindListenPort(const CService& bindAddr, std::string& strError = REF(std::string()));
  void StartNode(boost::thread_group& threadGroup);
  bool StopNode();
  void SocketSendData(CNode* pnode);
  
  // Signals for message handling
  struct CNodeSignals {
      boost::signals2::signal<bool(CNode*)> ProcessMessages;
      boost::signals2::signal<bool(CNode*, bool)> SendMessages;
  };
  
  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 AdvertizeLocal(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 SeenLocal(const CService& addr);
  bool IsLocal(const CService& addr);
  bool GetLocal(CService& addr, const CNetAddr* paddrPeer = NULL);
  bool IsReachable(const CNetAddr& addr);
  void SetReachable(enum Network net, bool fFlag = true);
  CAddress GetLocalAddress(const CNetAddr* paddrPeer = NULL);
  
  
  enum {
      MSG_TX = 1,
      MSG_BLOCK,
  };
  
  extern bool fDiscover;
  extern uint64_t nLocalServices;
  extern uint64_t nLocalHostNonce;
  extern CAddrMan addrman;
  
  extern std::vector<CNode*> vNodes;
  extern CCriticalSection cs_vNodes;
  extern std::map<CInv, CDataStream> mapRelay;
  extern std::deque<std::pair<int64_t, CInv>> vRelayExpiration;
  extern CCriticalSection cs_mapRelay;
  extern std::map<CInv, int64_t> mapAlreadyAskedFor;
  
  extern std::vector<std::string> vAddedNodes;
  extern CCriticalSection cs_vAddedNodes;
  
  
  class CNodeStats
  {
  public:
      uint64_t nServices;
      int64_t nLastSend;
      int64_t nLastRecv;
      int64_t nTimeConnected;
      int64_t nTimeOffset;
      std::string addrName;
      int nVersion;
      std::string strSubVer;
      bool fInbound;
      int nStartingHeight;
      int nMisbehavior;
      uint64_t nSendBytes;
      uint64_t nRecvBytes;
      bool fSyncNode;
      double dPingTime;
      double dPingWait;
      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(int nTypeIn, int nVersionIn) : hdrbuf(nTypeIn, nVersionIn), 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
  {
  public:
      // socket
      uint64_t nServices;
      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;
      CAddress addr;
      std::string addrName;
      CService addrLocal;
      int nVersion;
      std::string strSubVer;
      bool fOneShot;
      bool fClient;
      bool fInbound;
      bool fNetworkNode;
      bool fSuccessfullyConnected;
      bool fDisconnect;
      CSemaphoreGrant grantOutbound;
      int nRefCount;
  
  protected:
      // Denial-of-service detection/prevention
      // Key is IP address, value is banned-until-time
      static std::map<CNetAddr, int64_t> setBanned;
      static CCriticalSection cs_setBanned;
      int nMisbehavior;
  
  public:
      uint256 hashContinue;
      CBlockIndex* pindexLastGetBlocksBegin;
      uint256 hashLastGetBlocksEnd;
      int nStartingHeight;
      bool fStartSync;
  
      // flood relay
      std::vector<CAddress> vAddrToSend;
      mruset<CAddress> setAddrKnown;
      bool fGetAddr;
      std::set<uint256> setKnown;
  
      // inventory based relay
      mruset<CInv> setInventoryKnown;
      std::vector<CInv> vInventoryToSend;
      CCriticalSection cs_inventory;
      std::multimap<int64_t, CInv> mapAskFor;
  
      // 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;
      // Whether a ping is requested.
      bool fPingQueued;
  
      CNode(SOCKET hSocketIn, CAddress addrIn, std::string addrNameIn = "", bool fInboundIn = false) : ssSend(SER_NETWORK, INIT_PROTO_VERSION), setAddrKnown(5000)
      {
          nServices = 0;
          hSocket = hSocketIn;
          nRecvVersion = INIT_PROTO_VERSION;
          nLastSend = 0;
          nLastRecv = 0;
          nSendBytes = 0;
          nRecvBytes = 0;
          nTimeConnected = GetTime();
          nTimeOffset = 0;
          addr = addrIn;
          addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
          nVersion = 0;
          strSubVer = "";
          fOneShot = false;
          fClient = false; // set by version message
          fInbound = fInboundIn;
          fNetworkNode = false;
          fSuccessfullyConnected = false;
          fDisconnect = false;
          nRefCount = 0;
          nSendSize = 0;
          nSendOffset = 0;
          hashContinue = 0;
          pindexLastGetBlocksBegin = 0;
          hashLastGetBlocksEnd = 0;
          nStartingHeight = -1;
          fStartSync = false;
          fGetAddr = false;
          nMisbehavior = 0;
          setInventoryKnown.max_size(SendBufferSize() / 1000);
          nPingNonceSent = 0;
          nPingUsecStart = 0;
          nPingUsecTime = 0;
          fPingQueued = false;
  
          // Be shy and don't send version until we hear
          if (hSocket != INVALID_SOCKET && !fInbound)
              PushVersion();
      }
  
      ~CNode()
      {
          if (hSocket != INVALID_SOCKET) {
              closesocket(hSocket);
              hSocket = INVALID_SOCKET;
          }
      }
  
  private:
      // Network usage totals
      static CCriticalSection cs_totalBytesRecv;
      static CCriticalSection cs_totalBytesSent;
      static uint64_t nTotalBytesRecv;
      static uint64_t nTotalBytesSent;
  
      CNode(const CNode&);
      void operator=(const CNode&);
  
  public:
      int GetRefCount()
      {
          assert(nRefCount >= 0);
          return nRefCount;
      }
  
      // 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)
      {
          setAddrKnown.insert(addr);
      }
  
      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() && !setAddrKnown.count(addr))
              vAddrToSend.push_back(addr);
      }
  
  
      void AddInventoryKnown(const CInv& inv)
      {
          {
              LOCK(cs_inventory);
              setInventoryKnown.insert(inv);
          }
      }
  
      void PushInventory(const CInv& inv)
      {
          {
              LOCK(cs_inventory);
              if (!setInventoryKnown.count(inv))
                  vInventoryToSend.push_back(inv);
          }
      }
  
      void AskFor(const CInv& inv)
      {
          // We're using mapAskFor as a priority queue,
          // the key is the earliest time the request can be sent
          int64_t& nRequestTime = mapAlreadyAskedFor[inv];
          LogPrint("net", "askfor %s   %d (%s)\n", inv.ToString(), nRequestTime, DateTimeStrFormat("%H:%M:%S", nRequestTime / 1000000));
  
          // Make sure not to reuse time indexes to keep things in the same order
          int64_t nNow = (GetTime() - 1) * 1000000;
          static int64_t nLastTime;
          ++nLastTime;
          nNow = std::max(nNow, nLastTime);
          nLastTime = nNow;
  
          // Each retry is 2 minutes after the last
          nRequestTime = std::max(nRequestTime + 2 * 60 * 1000000, nNow);
          mapAskFor.insert(std::make_pair(nRequestTime, inv));
      }
  
  
      // TODO: Document the postcondition of this function.  Is cs_vSend locked?
      void BeginMessage(const char* pszCommand) EXCLUSIVE_LOCK_FUNCTION(cs_vSend)
      {
          ENTER_CRITICAL_SECTION(cs_vSend);
          assert(ssSend.size() == 0);
          ssSend << CMessageHeader(pszCommand, 0);
          LogPrint("net", "sending: %s ", pszCommand);
      }
  
      // TODO: Document the precondition of this function.  Is cs_vSend locked?
      void AbortMessage() UNLOCK_FUNCTION(cs_vSend)
      {
          ssSend.clear();
  
          LEAVE_CRITICAL_SECTION(cs_vSend);
  
          LogPrint("net", "(aborted)\n");
      }
  
      // TODO: Document the precondition of this function.  Is cs_vSend locked?
      void EndMessage() UNLOCK_FUNCTION(cs_vSend)
      {
          if (mapArgs.count("-dropmessagestest") && GetRand(atoi(mapArgs["-dropmessagestest"])) == 0) {
              LogPrint("net", "dropmessages DROPPING SEND MESSAGE\n");
              AbortMessage();
              return;
          }
  
          if (ssSend.size() == 0)
              return;
  
          // Set the size
          unsigned int nSize = ssSend.size() - CMessageHeader::HEADER_SIZE;
          memcpy((char*)&ssSend[CMessageHeader::MESSAGE_SIZE_OFFSET], &nSize, sizeof(nSize));
  
          // Set the checksum
          uint256 hash = Hash(ssSend.begin() + CMessageHeader::HEADER_SIZE, ssSend.end());
          unsigned int nChecksum = 0;
          memcpy(&nChecksum, &hash, sizeof(nChecksum));
          assert(ssSend.size() >= CMessageHeader::CHECKSUM_OFFSET + sizeof(nChecksum));
          memcpy((char*)&ssSend[CMessageHeader::CHECKSUM_OFFSET], &nChecksum, sizeof(nChecksum));
  
          LogPrint("net", "(%d bytes)\n", nSize);
  
          std::deque<CSerializeData>::iterator it = vSendMsg.insert(vSendMsg.end(), CSerializeData());
          ssSend.GetAndClear(*it);
          nSendSize += (*it).size();
  
          // If write queue empty, attempt "optimistic write"
          if (it == vSendMsg.begin())
              SocketSendData(this);
  
          LEAVE_CRITICAL_SECTION(cs_vSend);
      }
  
      void PushVersion();
  
  
      void PushMessage(const char* pszCommand)
      {
          try {
              BeginMessage(pszCommand);
              EndMessage();
          } catch (...) {
              AbortMessage();
              throw;
          }
      }
  
      template <typename T1>
      void PushMessage(const char* pszCommand, const T1& a1)
      {
          try {
              BeginMessage(pszCommand);
              ssSend << a1;
              EndMessage();
          } 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();
          } 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();
          } 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();
          } 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();
          } 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();
          } 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();
          } 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();
          } 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();
          } catch (...) {
              AbortMessage();
              throw;
          }
      }
  
      bool IsSubscribed(unsigned int nChannel);
      void Subscribe(unsigned int nChannel, unsigned int nHops = 0);
      void CancelSubscribe(unsigned int nChannel);
      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);
      bool Misbehaving(int howmuch); // 1 == a little, 100 == a lot
      void copyStats(CNodeStats& stats);
  
      // Network stats
      static void RecordBytesRecv(uint64_t bytes);
      static void RecordBytesSent(uint64_t bytes);
  
      static uint64_t GetTotalBytesRecv();
      static uint64_t GetTotalBytesSent();
  };
  
  inline void RelayInventory(const CInv& inv)
  {
      // Put on lists to offer to the other nodes
      {
          LOCK(cs_vNodes);
          BOOST_FOREACH (CNode* pnode, vNodes)
              pnode->PushInventory(inv);
      }
  }
  
  class CTransaction;
  void RelayTransaction(const CTransaction& tx, const uint256& hash);
  void RelayTransaction(const CTransaction& tx, const uint256& hash, const CDataStream& ss);
  
  /** 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);
  };
  
  #endif
  