text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2017 The Bitcoin Core developers
  // Copyright (c) 2019 The Unit 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_PROCESSING_H
  #define BITCOIN_NET_PROCESSING_H
  
  #include <net.h>
  #include <validationinterface.h>
  #include <consensus/params.h>
  
  /** Default for -maxorphantx, maximum number of orphan transactions kept in memory */
  static const unsigned int DEFAULT_MAX_ORPHAN_TRANSACTIONS = 100;
  /** Expiration time for orphan transactions in seconds */
  static const int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60;
  /** Minimum time between orphan transactions expire time checks in seconds */
  static const int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60;
  /** Default number of orphan+recently-replaced txn to keep around for block reconstruction */
  static const unsigned int DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN = 100;
  /** Headers download timeout expressed in microseconds
   *  Timeout = base + per_header * (expected number of headers) */
  static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_BASE = 15 * 60 * 1000000; // 15 minutes
  static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1000; // 1ms/header
  /** Protect at least this many outbound peers from disconnection due to slow/
   * behind headers chain.
   */
  static constexpr int32_t MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT = 4;
  /** Timeout for (unprotected) outbound peers to sync to our chainwork, in seconds */
  static constexpr int64_t CHAIN_SYNC_TIMEOUT = 20 * 60; // 20 minutes
  /** How frequently to check for stale tips, in seconds */
  static constexpr int64_t STALE_CHECK_INTERVAL = 2.5 * 60; // 2.5 minutes
  /** How frequently to check for extra outbound peers and disconnect, in seconds */
  static constexpr int64_t EXTRA_PEER_CHECK_INTERVAL = 45;
  /** Minimum time an outbound-peer-eviction candidate must be connected for, in order to evict, in seconds */
  static constexpr int64_t MINIMUM_CONNECT_TIME = 30;
  
  class PeerLogicValidation : public CValidationInterface, public NetEventsInterface {
  private:
      CConnman* const connman;
  
  public:
      explicit PeerLogicValidation(CConnman* connman, CScheduler &scheduler);
  
      void BlockConnected(const std::shared_ptr<const CBlock>& pblock, const CBlockIndex* pindexConnected, const std::vector<CTransactionRef>& vtxConflicted) override;
      void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) override;
      void BlockChecked(const CBlock& block, const CValidationState& state) override;
      void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& pblock) override;
  
  
      void InitializeNode(CNode* pnode) override;
      void FinalizeNode(NodeId nodeid, bool& fUpdateConnectionTime) override;
      /** Process protocol messages received from a given node */
      bool ProcessMessages(CNode* pfrom, std::atomic<bool>& interrupt) override;
      /**
      * Send queued protocol messages to be sent to a give node.
      *
      * @param[in]   pto             The node which we are sending messages to.
      * @param[in]   interrupt       Interrupt condition for processing threads
      * @return                      True if there is more work to be done
      */
      bool SendMessages(CNode* pto, std::atomic<bool>& interrupt) override;
  
      void ConsiderEviction(CNode *pto, int64_t time_in_seconds);
      void CheckForStaleTipAndEvictPeers(const Consensus::Params &consensusParams);
      void EvictExtraOutboundPeers(int64_t time_in_seconds);
  
  private:
      int64_t m_stale_tip_check_time; //! Next time to check for stale tip
  };
  
  struct CNodeStateStats {
      int nMisbehavior;
      int nSyncHeight;
      int nCommonHeight;
      std::vector<int> vHeightInFlight;
  };
  
  /** Get statistics from node state */
  bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats);
  /** Increase a node's misbehavior score. */
  void Misbehaving(NodeId nodeid, int howmuch);
  
  #endif // BITCOIN_NET_PROCESSING_H
  