net.h

Go to the documentation of this file.

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2019 The Bitcoin Core developers
// Copyright (c) 2017-2019 The Bitcoin 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 <amount.h>
#include <avalanche/delegation.h>
#include <bloom.h>
#include <chainparams.h>
#include <compat.h>
#include <crypto/siphash.h>
#include <hash.h>
#include <limitedmap.h>
#include <net_permissions.h>
#include <netaddress.h>
#include <protocol.h>
#include <random.h>
#include <streams.h>
#include <sync.h>
#include <threadinterrupt.h>
#include <uint256.h>
#include <validation.h> // For cs_main

#include <atomic>
#include <condition_variable>
#include <cstdint>
#include <deque>
#include <memory>
#include <thread>

#ifndef WIN32
#include <arpa/inet.h>
#endif

class BanMan;
class Config;
class CNode;
class CScheduler;
struct bilingual_str;

static const bool DEFAULT_WHITELISTRELAY = true;
static const bool DEFAULT_WHITELISTFORCERELAY = false;

static const int PING_INTERVAL = 2 * 60;
static const int TIMEOUT_INTERVAL = 20 * 60;
static const int FEELER_INTERVAL = 120;
static const unsigned int MAX_INV_SZ = 50000;
static_assert(MAX_PROTOCOL_MESSAGE_LENGTH > MAX_INV_SZ * sizeof(CInv),
              "Max protocol message length must be greater than largest "
              "possible INV message");
static const unsigned int MAX_LOCATOR_SZ = 101;
static const unsigned int MAX_ADDR_TO_SEND = 1000;
static const unsigned int MAX_SUBVERSION_LENGTH = 256;
static const int MAX_OUTBOUND_FULL_RELAY_CONNECTIONS = 8;
static const int MAX_ADDNODE_CONNECTIONS = 8;
static const int MAX_BLOCKS_ONLY_CONNECTIONS = 2;
static const bool DEFAULT_LISTEN = true;
#ifdef USE_UPNP
static const bool DEFAULT_UPNP = USE_UPNP;
#else
static const bool DEFAULT_UPNP = false;
#endif

static const unsigned int DEFAULT_MAX_PEER_CONNECTIONS = 4096;
static const uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
static const uint64_t MAX_UPLOAD_TIMEFRAME = 60 * 60 * 24;
static const bool DEFAULT_BLOCKSONLY = false;
static const int64_t DEFAULT_PEER_CONNECT_TIMEOUT = 60;

static const bool DEFAULT_FORCEDNSSEED = false;
static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
static const size_t DEFAULT_MAXSENDBUFFER = 1 * 1000;

typedef int64_t NodeId;

static constexpr NodeId NO_NODE = -1;

struct AddedNodeInfo {
    std::string strAddedNode;
    CService resolvedAddress;
    bool fConnected;
    bool fInbound;
};

struct CNodeStats;
class CClientUIInterface;

struct CSerializedNetMsg {
    CSerializedNetMsg() = default;
    CSerializedNetMsg(CSerializedNetMsg &&) = default;
    CSerializedNetMsg &operator=(CSerializedNetMsg &&) = default;
    // No copying, only moves.
    CSerializedNetMsg(const CSerializedNetMsg &msg) = delete;
    CSerializedNetMsg &operator=(const CSerializedNetMsg &) = delete;

    std::vector<uint8_t> data;
    std::string m_type;
};

enum class ConnectionType {
    INBOUND,
    OUTBOUND,
    MANUAL,
    FEELER,
    BLOCK_RELAY,
    ADDR_FETCH,
};

namespace {
struct CConnmanTest;
}

class NetEventsInterface;
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;
        int nMaxConnections = 0;
        int m_max_outbound_full_relay = 0;
        int m_max_outbound_block_relay = 0;
        int nMaxAddnode = 0;
        int nMaxFeeler = 0;
        int nBestHeight = 0;
        CClientUIInterface *uiInterface = nullptr;
        NetEventsInterface *m_msgproc = nullptr;
        BanMan *m_banman = nullptr;
        unsigned int nSendBufferMaxSize = 0;
        unsigned int nReceiveFloodSize = 0;
        uint64_t nMaxOutboundTimeframe = 0;
        uint64_t nMaxOutboundLimit = 0;
        int64_t m_peer_connect_timeout = DEFAULT_PEER_CONNECT_TIMEOUT;
        std::vector<std::string> vSeedNodes;
        std::vector<NetWhitelistPermissions> vWhitelistedRange;
        std::vector<NetWhitebindPermissions> vWhiteBinds;
        std::vector<CService> vBinds;
        bool m_use_addrman_outgoing = true;
        std::vector<std::string> m_specified_outgoing;
        std::vector<std::string> m_added_nodes;
        std::vector<bool> m_asmap;
    };

    void Init(const Options &connOptions) {
        nLocalServices = connOptions.nLocalServices;
        nMaxConnections = connOptions.nMaxConnections;
        m_use_addrman_outgoing = connOptions.m_use_addrman_outgoing;
        nMaxAddnode = connOptions.nMaxAddnode;
        nMaxFeeler = connOptions.nMaxFeeler;
        {
            // Lock cs_main to prevent a potential race with the peer validation
            // logic thread.
            LOCK(::cs_main);
            m_max_outbound_full_relay =
                std::min(connOptions.m_max_outbound_full_relay,
                         connOptions.nMaxConnections);
            m_max_outbound_block_relay = connOptions.m_max_outbound_block_relay;
            m_max_outbound = m_max_outbound_full_relay +
                             m_max_outbound_block_relay + nMaxFeeler;
        }
        nBestHeight = connOptions.nBestHeight;
        clientInterface = connOptions.uiInterface;
        m_banman = connOptions.m_banman;
        m_msgproc = connOptions.m_msgproc;
        nSendBufferMaxSize = connOptions.nSendBufferMaxSize;
        nReceiveFloodSize = connOptions.nReceiveFloodSize;
        m_peer_connect_timeout = connOptions.m_peer_connect_timeout;
        {
            LOCK(cs_totalBytesSent);
            nMaxOutboundTimeframe = connOptions.nMaxOutboundTimeframe;
            nMaxOutboundLimit = connOptions.nMaxOutboundLimit;
        }
        vWhitelistedRange = connOptions.vWhitelistedRange;
        {
            LOCK(cs_vAddedNodes);
            vAddedNodes = connOptions.m_added_nodes;
        }
    }

    CConnman(const Config &configIn, uint64_t seed0, uint64_t seed1);
    ~CConnman();

    bool Start(CScheduler &scheduler, const Options &options);

    void StopThreads();
    void StopNodes();
    void Stop() {
        StopThreads();
        StopNodes();
    };

    void Interrupt();
    bool GetNetworkActive() const { return fNetworkActive; };
    bool GetUseAddrmanOutgoing() const { return m_use_addrman_outgoing; };
    void SetNetworkActive(bool active);
    void
    OpenNetworkConnection(const CAddress &addrConnect, bool fCountFailure,
                          CSemaphoreGrant *grantOutbound = nullptr,
                          const char *strDest = nullptr,
                          ConnectionType conn_type = ConnectionType::OUTBOUND);
    bool CheckIncomingNonce(uint64_t nonce);

    bool ForNode(NodeId id, std::function<bool(CNode *pnode)> func);

    void PushMessage(CNode *pnode, CSerializedNetMsg &&msg);

    template <typename Callable> void ForEachNode(Callable &&func) {
        LOCK(cs_vNodes);
        for (auto &&node : vNodes) {
            if (NodeFullyConnected(node)) {
                func(node);
            }
        }
    };

    template <typename Callable> void ForEachNode(Callable &&func) const {
        LOCK(cs_vNodes);
        for (auto &&node : vNodes) {
            if (NodeFullyConnected(node)) {
                func(node);
            }
        }
    };

    template <typename Callable, typename CallableAfter>
    void ForEachNodeThen(Callable &&pre, CallableAfter &&post) {
        LOCK(cs_vNodes);
        for (auto &&node : vNodes) {
            if (NodeFullyConnected(node)) {
                pre(node);
            }
        }
        post();
    };

    template <typename Callable, typename CallableAfter>
    void ForEachNodeThen(Callable &&pre, CallableAfter &&post) const {
        LOCK(cs_vNodes);
        for (auto &&node : vNodes) {
            if (NodeFullyConnected(node)) {
                pre(node);
            }
        }
        post();
    };

    // Addrman functions
    void SetServices(const CService &addr, ServiceFlags nServices);
    void MarkAddressGood(const CAddress &addr);
    void AddNewAddresses(const std::vector<CAddress> &vAddr,
                         const CAddress &addrFrom, int64_t nTimePenalty = 0);
    std::vector<CAddress> GetAddresses();

    // This allows temporarily exceeding m_max_outbound_full_relay, with the
    // goal of finding a peer that is better than all our current peers.
    void SetTryNewOutboundPeer(bool flag);
    bool GetTryNewOutboundPeer();

    // Return the number of outbound peers we have in excess of our target (eg,
    // if we previously called SetTryNewOutboundPeer(true), and have since set
    // to false, we may have extra peers that we wish to disconnect). This may
    // return a value less than (num_outbound_connections - num_outbound_slots)
    // in cases where some outbound connections are not yet fully connected, or
    // not yet fully disconnected.
    int GetExtraOutboundCount();

    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(const CSubNet &subnet);
    bool DisconnectNode(const CNetAddr &addr);
    bool DisconnectNode(NodeId id);

    ServiceFlags GetLocalServices() const;

    void SetMaxOutboundTarget(uint64_t limit);
    uint64_t GetMaxOutboundTarget();

    void SetMaxOutboundTimeframe(uint64_t timeframe);
    uint64_t GetMaxOutboundTimeframe();

    bool OutboundTargetReached(bool historicalBlockServingLimit);

    uint64_t GetOutboundTargetBytesLeft();

    uint64_t GetMaxOutboundTimeLeftInCycle();

    uint64_t GetTotalBytesRecv();
    uint64_t GetTotalBytesSent();

    void SetBestHeight(int height);
    int GetBestHeight() const;

    CSipHasher GetDeterministicRandomizer(uint64_t id) const;

    unsigned int GetReceiveFloodSize() const;

    void WakeMessageHandler();

    int64_t PoissonNextSendInbound(int64_t now, int average_interval_seconds);

    void SetAsmap(std::vector<bool> asmap) {
        addrman.m_asmap = std::move(asmap);
    }

private:
    struct ListenSocket {
    public:
        SOCKET socket;
        inline void AddSocketPermissionFlags(NetPermissionFlags &flags) const {
            NetPermissions::AddFlag(flags, m_permissions);
        }
        ListenSocket(SOCKET socket_, NetPermissionFlags permissions_)
            : socket(socket_), m_permissions(permissions_) {}

    private:
        NetPermissionFlags m_permissions;
    };

    bool BindListenPort(const CService &bindAddr, bilingual_str &strError,
                        NetPermissionFlags permissions);
    bool Bind(const CService &addr, unsigned int flags,
              NetPermissionFlags permissions);
    bool InitBinds(const std::vector<CService> &binds,
                   const std::vector<NetWhitebindPermissions> &whiteBinds);
    void ThreadOpenAddedConnections();
    void AddAddrFetch(const std::string &strDest);
    void ProcessAddrFetch();
    void ThreadOpenConnections(std::vector<std::string> connect);
    void ThreadMessageHandler();
    void AcceptConnection(const ListenSocket &hListenSocket);
    void DisconnectNodes();
    void NotifyNumConnectionsChanged();
    void InactivityCheck(CNode *pnode);
    bool GenerateSelectSet(std::set<SOCKET> &recv_set,
                           std::set<SOCKET> &send_set,
                           std::set<SOCKET> &error_set);
    void SocketEvents(std::set<SOCKET> &recv_set, std::set<SOCKET> &send_set,
                      std::set<SOCKET> &error_set);
    void SocketHandler();
    void ThreadSocketHandler();
    void ThreadDNSAddressSeed();

    uint64_t CalculateKeyedNetGroup(const CAddress &ad) const;

    CNode *FindNode(const CNetAddr &ip);
    CNode *FindNode(const CSubNet &subNet);
    CNode *FindNode(const std::string &addrName);
    CNode *FindNode(const CService &addr);

    bool AttemptToEvictConnection();
    CNode *ConnectNode(CAddress addrConnect, const char *pszDest,
                       bool fCountFailure, ConnectionType conn_type);
    void AddWhitelistPermissionFlags(NetPermissionFlags &flags,
                                     const CNetAddr &addr) const;

    void DeleteNode(CNode *pnode);

    NodeId GetNewNodeId();

    size_t SocketSendData(CNode *pnode) const;
    void DumpAddresses();

    // 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);

    const Config *config;

    // Network usage totals
    RecursiveMutex cs_totalBytesRecv;
    RecursiveMutex cs_totalBytesSent;
    uint64_t nTotalBytesRecv GUARDED_BY(cs_totalBytesRecv){0};
    uint64_t nTotalBytesSent GUARDED_BY(cs_totalBytesSent){0};

    // outbound limit & stats
    uint64_t nMaxOutboundTotalBytesSentInCycle GUARDED_BY(cs_totalBytesSent);
    uint64_t nMaxOutboundCycleStartTime GUARDED_BY(cs_totalBytesSent);
    uint64_t nMaxOutboundLimit GUARDED_BY(cs_totalBytesSent);
    uint64_t nMaxOutboundTimeframe GUARDED_BY(cs_totalBytesSent);

    // P2P timeout in seconds
    int64_t m_peer_connect_timeout;

    // Whitelisted ranges. Any node connecting from these is automatically
    // whitelisted (as well as those connecting to whitelisted binds).
    std::vector<NetWhitelistPermissions> vWhitelistedRange;

    unsigned int nSendBufferMaxSize{0};
    unsigned int nReceiveFloodSize{0};

    std::vector<ListenSocket> vhListenSocket;
    std::atomic<bool> fNetworkActive{true};
    bool fAddressesInitialized{false};
    CAddrMan addrman;
    std::deque<std::string> m_addr_fetches GUARDED_BY(m_addr_fetches_mutex);
    RecursiveMutex m_addr_fetches_mutex;
    std::vector<std::string> vAddedNodes GUARDED_BY(cs_vAddedNodes);
    RecursiveMutex cs_vAddedNodes;
    std::vector<CNode *> vNodes GUARDED_BY(cs_vNodes);
    std::list<CNode *> vNodesDisconnected;
    mutable RecursiveMutex cs_vNodes;
    std::atomic<NodeId> nLastNodeId{0};
    unsigned int nPrevNodeCount{0};

    ServiceFlags nLocalServices;

    std::unique_ptr<CSemaphore> semOutbound;
    std::unique_ptr<CSemaphore> semAddnode;
    int nMaxConnections;

    // How many full-relay (tx, block, addr) outbound peers we want
    int m_max_outbound_full_relay;

    // How many block-relay only outbound peers we want
    // We do not relay tx or addr messages with these peers
    int m_max_outbound_block_relay;

    int nMaxAddnode;
    int nMaxFeeler;
    int m_max_outbound;
    bool m_use_addrman_outgoing;
    std::atomic<int> nBestHeight;
    CClientUIInterface *clientInterface;
    NetEventsInterface *m_msgproc;
    BanMan *m_banman;

    const uint64_t nSeed0, nSeed1;

    bool fMsgProcWake GUARDED_BY(mutexMsgProc);

    std::condition_variable condMsgProc;
    Mutex mutexMsgProc;
    std::atomic<bool> flagInterruptMsgProc{false};

    CThreadInterrupt interruptNet;

    std::thread threadDNSAddressSeed;
    std::thread threadSocketHandler;
    std::thread threadOpenAddedConnections;
    std::thread threadOpenConnections;
    std::thread threadMessageHandler;

    std::atomic_bool m_try_another_outbound_peer;

    std::atomic<int64_t> m_next_send_inv_to_incoming{0};

    friend struct ::CConnmanTest;
    friend struct ConnmanTestMsg;
};

void Discover();
void StartMapPort();
void InterruptMapPort();
void StopMapPort();
unsigned short GetListenPort();

class NetEventsInterface {
public:
    virtual bool ProcessMessages(const Config &config, CNode *pnode,
                                 std::atomic<bool> &interrupt) = 0;
    virtual bool SendMessages(const Config &config, CNode *pnode,
                              std::atomic<bool> &interrupt) = 0;
    virtual void InitializeNode(const Config &config, CNode *pnode) = 0;
    virtual void FinalizeNode(const Config &config, NodeId id,
                              bool &update_connection_time) = 0;

protected:
    ~NetEventsInterface() = default;
};

enum {
    // unknown
    LOCAL_NONE,
    // address a local interface listens on
    LOCAL_IF,
    // address explicit bound to
    LOCAL_BIND,
    // address reported by UPnP
    LOCAL_UPNP,
    // address explicitly specified (-externalip=)
    LOCAL_MANUAL,

    LOCAL_MAX
};

bool IsPeerAddrLocalGood(CNode *pnode);
void AdvertiseLocal(CNode *pnode);

void SetReachable(enum Network net, bool reachable);
bool IsReachable(enum Network net);
bool IsReachable(const CNetAddr &addr);

bool AddLocal(const CService &addr, int nScore = LOCAL_NONE);
bool AddLocal(const CNetAddr &addr, int nScore = LOCAL_NONE);
void RemoveLocal(const CService &addr);
bool SeenLocal(const CService &addr);
bool IsLocal(const CService &addr);
bool GetLocal(CService &addr, const CNetAddr *paddrPeer = nullptr);
CAddress GetLocalAddress(const CNetAddr *paddrPeer,
                         ServiceFlags nLocalServices);

extern bool fDiscover;
extern bool fListen;
extern bool g_relay_txes;

struct LocalServiceInfo {
    int nScore;
    int nPort;
};

extern RecursiveMutex cs_mapLocalHost;
extern std::map<CNetAddr, LocalServiceInfo>
    mapLocalHost GUARDED_BY(cs_mapLocalHost);

extern const std::string NET_MESSAGE_COMMAND_OTHER;
// Command, total bytes
typedef std::map<std::string, uint64_t> mapMsgCmdSize;

struct CNodeStats {
    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;
    bool m_manual_connection;
    int nStartingHeight;
    uint64_t nSendBytes;
    mapMsgCmdSize mapSendBytesPerMsgCmd;
    uint64_t nRecvBytes;
    mapMsgCmdSize mapRecvBytesPerMsgCmd;
    NetPermissionFlags m_permissionFlags;
    bool m_legacyWhitelisted;
    int64_t m_ping_usec;
    int64_t m_ping_wait_usec;
    int64_t m_min_ping_usec;
    Amount minFeeFilter;
    // Our address, as reported by the peer
    std::string addrLocal;
    // Address of this peer
    CAddress addr;
    // Bind address of our side of the connection
    CAddress addrBind;
    uint32_t m_mapped_as;
};

class CNetMessage {
public:
    // received message data
    CDataStream m_recv;
    // time (in microseconds) of message receipt.
    int64_t m_time = 0;
    bool m_valid_netmagic = false;
    bool m_valid_header = false;
    bool m_valid_checksum = false;
    // size of the payload
    uint32_t m_message_size = 0;
    // used wire size of the message (including header/checksum)
    uint32_t m_raw_message_size = 0;
    std::string m_command;

    CNetMessage(CDataStream &&recv_in) : m_recv(std::move(recv_in)) {}

    void SetVersion(int nVersionIn) { m_recv.SetVersion(nVersionIn); }
};

class TransportDeserializer {
public:
    // returns true if the current deserialization is complete
    virtual bool Complete() const = 0;
    // set the serialization context version
    virtual void SetVersion(int version) = 0;
    // read and deserialize data
    virtual int Read(const Config &config, const char *data,
                     uint32_t bytes) = 0;
    // decomposes a message from the context
    virtual CNetMessage GetMessage(const Config &config, int64_t time) = 0;
    virtual ~TransportDeserializer() {}
};

class V1TransportDeserializer final : public TransportDeserializer {
private:
    mutable CHash256 hasher;
    mutable uint256 data_hash;

    // Parsing header (false) or data (true)
    bool in_data;
    // Partially received header.
    CDataStream hdrbuf;
    // Complete header.
    CMessageHeader hdr;
    // Received message data.
    CDataStream vRecv;
    uint32_t nHdrPos;
    uint32_t nDataPos;

    const uint256 &GetMessageHash() const;
    int readHeader(const Config &config, const char *pch, uint32_t nBytes);
    int readData(const char *pch, uint32_t nBytes);

    void Reset() {
        vRecv.clear();
        hdrbuf.clear();
        hdrbuf.resize(24);
        in_data = false;
        nHdrPos = 0;
        nDataPos = 0;
        data_hash.SetNull();
        hasher.Reset();
    }

public:
    V1TransportDeserializer(
        const CMessageHeader::MessageMagic &pchMessageStartIn, int nTypeIn,
        int nVersionIn)
        : hdrbuf(nTypeIn, nVersionIn), hdr(pchMessageStartIn),
          vRecv(nTypeIn, nVersionIn) {
        Reset();
    }

    bool Complete() const override {
        if (!in_data) {
            return false;
        }

        return (hdr.nMessageSize == nDataPos);
    }

    void SetVersion(int nVersionIn) override {
        hdrbuf.SetVersion(nVersionIn);
        vRecv.SetVersion(nVersionIn);
    }
    int Read(const Config &config, const char *pch, uint32_t nBytes) override {
        int ret =
            in_data ? readData(pch, nBytes) : readHeader(config, pch, nBytes);
        if (ret < 0) {
            Reset();
        }
        return ret;
    }

    CNetMessage GetMessage(const Config &config, int64_t time) override;
};

class TransportSerializer {
public:
    // prepare message for transport (header construction, error-correction
    // computation, payload encryption, etc.)
    virtual void prepareForTransport(const Config &config,
                                     CSerializedNetMsg &msg,
                                     std::vector<uint8_t> &header) = 0;
    virtual ~TransportSerializer() {}
};

class V1TransportSerializer : public TransportSerializer {
public:
    void prepareForTransport(const Config &config, CSerializedNetMsg &msg,
                             std::vector<uint8_t> &header) override;
};

class CNode {
    friend class CConnman;
    friend struct ConnmanTestMsg;

public:
    std::unique_ptr<TransportDeserializer> m_deserializer;
    std::unique_ptr<TransportSerializer> m_serializer;

    // socket
    std::atomic<ServiceFlags> nServices{NODE_NONE};
    SOCKET hSocket GUARDED_BY(cs_hSocket);
    // Total size of all vSendMsg entries.
    size_t nSendSize{0};
    // Offset inside the first vSendMsg already sent.
    size_t nSendOffset{0};
    uint64_t nSendBytes GUARDED_BY(cs_vSend){0};
    std::deque<std::vector<uint8_t>> vSendMsg GUARDED_BY(cs_vSend);
    RecursiveMutex cs_vSend;
    RecursiveMutex cs_hSocket;
    RecursiveMutex cs_vRecv;

    RecursiveMutex cs_vProcessMsg;
    std::list<CNetMessage> vProcessMsg GUARDED_BY(cs_vProcessMsg);
    size_t nProcessQueueSize{0};

    RecursiveMutex cs_sendProcessing;

    std::deque<CInv> vRecvGetData;
    uint64_t nRecvBytes GUARDED_BY(cs_vRecv){0};
    std::atomic<int> nRecvVersion{INIT_PROTO_VERSION};

    std::atomic<int64_t> nLastSend{0};
    std::atomic<int64_t> nLastRecv{0};
    const int64_t nTimeConnected;
    std::atomic<int64_t> nTimeOffset{0};
    // Address of this peer
    const CAddress addr;
    // Bind address of our side of the connection
    const CAddress addrBind;
    std::atomic<int> nVersion{0};
    // The nonce provided by the remote host.
    uint64_t nRemoteHostNonce{0};
    // The extra entropy provided by the remote host.
    uint64_t nRemoteExtraEntropy{0};
    RecursiveMutex cs_SubVer;
    std::string cleanSubVer GUARDED_BY(cs_SubVer){};
    // This peer is preferred for eviction.
    bool m_prefer_evict{false};
    bool HasPermission(NetPermissionFlags permission) const {
        return NetPermissions::HasFlag(m_permissionFlags, permission);
    }
    // This boolean is unusued in actual processing, only present for backward
    // compatibility at RPC/QT level
    bool m_legacyWhitelisted{false};
    // set by version message
    bool fClient{false};
    // after BIP159, set by version message
    bool m_limited_node{false};
    std::atomic_bool fSuccessfullyConnected{false};
    // Setting fDisconnect to true will cause the node to be disconnected the
    // next time DisconnectNodes() runs
    std::atomic_bool fDisconnect{false};
    bool fSentAddr{false};
    CSemaphoreGrant grantOutbound;
    std::atomic<int> nRefCount{0};

    const uint64_t nKeyedNetGroup;
    std::atomic_bool fPauseRecv{false};
    std::atomic_bool fPauseSend{false};

    bool IsOutboundOrBlockRelayConn() const {
        switch (m_conn_type) {
            case ConnectionType::OUTBOUND:
            case ConnectionType::BLOCK_RELAY:
                return true;
            case ConnectionType::INBOUND:
            case ConnectionType::MANUAL:
            case ConnectionType::ADDR_FETCH:
            case ConnectionType::FEELER:
                return false;
        }

        assert(false);
    }

    bool IsFullOutboundConn() const {
        return m_conn_type == ConnectionType::OUTBOUND;
    }

    bool IsManualConn() const { return m_conn_type == ConnectionType::MANUAL; }

    bool IsBlockOnlyConn() const {
        return m_conn_type == ConnectionType::BLOCK_RELAY;
    }

    bool IsFeelerConn() const { return m_conn_type == ConnectionType::FEELER; }

    bool IsAddrFetchConn() const {
        return m_conn_type == ConnectionType::ADDR_FETCH;
    }

    bool IsInboundConn() const {
        return m_conn_type == ConnectionType::INBOUND;
    }

    bool ExpectServicesFromConn() const {
        switch (m_conn_type) {
            case ConnectionType::INBOUND:
            case ConnectionType::MANUAL:
            case ConnectionType::FEELER:
                return false;
            case ConnectionType::OUTBOUND:
            case ConnectionType::BLOCK_RELAY:
            case ConnectionType::ADDR_FETCH:
                return true;
        }

        assert(false);
    }

protected:
    mapMsgCmdSize mapSendBytesPerMsgCmd;
    mapMsgCmdSize mapRecvBytesPerMsgCmd GUARDED_BY(cs_vRecv);

public:
    BlockHash hashContinue;
    std::atomic<int> nStartingHeight{-1};

    // flood relay
    std::vector<CAddress> vAddrToSend;
    std::unique_ptr<CRollingBloomFilter> m_addr_known = nullptr;
    bool fGetAddr{false};
    std::chrono::microseconds m_next_addr_send GUARDED_BY(cs_sendProcessing){0};
    std::chrono::microseconds
        m_next_local_addr_send GUARDED_BY(cs_sendProcessing){0};

    bool IsAddrRelayPeer() const { return m_addr_known != nullptr; }

    // List of block ids we still have to announce.
    // There is no final sorting before sending, as they are always sent
    // immediately and in the order requested.
    std::vector<BlockHash> vInventoryBlockToSend GUARDED_BY(cs_inventory);
    RecursiveMutex cs_inventory;

    struct TxRelay {
        TxRelay() { pfilter = std::make_unique<CBloomFilter>(); }
        mutable RecursiveMutex cs_filter;
        // 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 GUARDED_BY(cs_filter){false};
        std::unique_ptr<CBloomFilter> pfilter PT_GUARDED_BY(cs_filter)
            GUARDED_BY(cs_filter);

        mutable RecursiveMutex cs_tx_inventory;
        CRollingBloomFilter filterInventoryKnown GUARDED_BY(cs_tx_inventory){
            50000, 0.000001};
        // 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<TxId> setInventoryTxToSend;
        // Used for BIP35 mempool sending
        bool fSendMempool GUARDED_BY(cs_tx_inventory){false};
        // Last time a "MEMPOOL" request was serviced.
        std::atomic<std::chrono::seconds> m_last_mempool_req{
            std::chrono::seconds{0}};
        std::chrono::microseconds nNextInvSend{0};

        RecursiveMutex cs_feeFilter;
        // Minimum fee rate with which to filter inv's to this node
        Amount minFeeFilter GUARDED_BY(cs_feeFilter){Amount::zero()};
        Amount lastSentFeeFilter{Amount::zero()};
        int64_t nextSendTimeFeeFilter{0};
    };

    // m_tx_relay == nullptr if we're not relaying transactions with this peer
    std::unique_ptr<TxRelay> m_tx_relay;

    struct AvalancheState {
        AvalancheState() {}

        avalanche::Delegation delegation;
    };

    // m_avalanche_state == nullptr if we're not using avalanche with this peer
    std::unique_ptr<AvalancheState> m_avalanche_state;

    // Used for headers announcements - unfiltered blocks to relay
    std::vector<BlockHash> vBlockHashesToAnnounce GUARDED_BY(cs_inventory);

    // Block and TXN accept times
    std::atomic<int64_t> nLastBlockTime{0};
    std::atomic<int64_t> nLastTXTime{0};

    // Ping time measurement:
    // The pong reply we're expecting, or 0 if no pong expected.
    std::atomic<uint64_t> nPingNonceSent{0};
    // Time (in usec) the last ping was sent, or 0 if no ping was ever sent.
    std::atomic<int64_t> nPingUsecStart{0};
    // Last measured round-trip time.
    std::atomic<int64_t> nPingUsecTime{0};
    // Best measured round-trip time.
    std::atomic<int64_t> nMinPingUsecTime{std::numeric_limits<int64_t>::max()};
    // Whether a ping is requested.
    std::atomic<bool> fPingQueued{false};

    std::set<TxId> orphan_work_set;

    CNode(NodeId id, ServiceFlags nLocalServicesIn, int nMyStartingHeightIn,
          SOCKET hSocketIn, const CAddress &addrIn, uint64_t nKeyedNetGroupIn,
          uint64_t nLocalHostNonceIn, uint64_t nLocalExtraEntropyIn,
          const CAddress &addrBindIn, const std::string &addrNameIn,
          ConnectionType conn_type_in);
    ~CNode();
    CNode(const CNode &) = delete;
    CNode &operator=(const CNode &) = delete;

private:
    const NodeId id;
    const uint64_t nLocalHostNonce;
    const uint64_t nLocalExtraEntropy;
    const ConnectionType m_conn_type;

    const ServiceFlags nLocalServices;

    const int nMyStartingHeight;
    int nSendVersion{0};
    NetPermissionFlags m_permissionFlags{PF_NONE};
    // Used only by SocketHandler thread
    std::list<CNetMessage> vRecvMsg;

    mutable RecursiveMutex cs_addrName;
    std::string addrName GUARDED_BY(cs_addrName);

    // Our address, as reported by the peer
    CService addrLocal GUARDED_BY(cs_addrLocal);
    mutable RecursiveMutex cs_addrLocal;

public:
    NodeId GetId() const { return id; }

    uint64_t GetLocalNonce() const { return nLocalHostNonce; }
    uint64_t GetLocalExtraEntropy() const { return nLocalExtraEntropy; }

    int GetMyStartingHeight() const { return nMyStartingHeight; }

    int GetRefCount() const {
        assert(nRefCount >= 0);
        return nRefCount;
    }

    bool ReceiveMsgBytes(const Config &config, const char *pch, uint32_t nBytes,
                         bool &complete);

    void SetRecvVersion(int nVersionIn) { nRecvVersion = nVersionIn; }
    int GetRecvVersion() const { return nRecvVersion; }
    void SetSendVersion(int nVersionIn);
    int GetSendVersion() const;

    CService GetAddrLocal() const;
    void SetAddrLocal(const CService &addrLocalIn);

    CNode *AddRef() {
        nRefCount++;
        return this;
    }

    void Release() { nRefCount--; }

    void AddAddressKnown(const CAddress &_addr) {
        assert(m_addr_known);
        m_addr_known->insert(_addr.GetKey());
    }

    void PushAddress(const CAddress &_addr, FastRandomContext &insecure_rand) {
        // Known checking here is only to save space from duplicates.
        // SendMessages will filter it again for knowns that were added
        // after addresses were pushed.
        assert(m_addr_known);
        if (_addr.IsValid() && !m_addr_known->contains(_addr.GetKey())) {
            if (vAddrToSend.size() >= MAX_ADDR_TO_SEND) {
                vAddrToSend[insecure_rand.randrange(vAddrToSend.size())] =
                    _addr;
            } else {
                vAddrToSend.push_back(_addr);
            }
        }
    }

    void AddKnownTx(const TxId &txid) {
        if (m_tx_relay != nullptr) {
            LOCK(m_tx_relay->cs_tx_inventory);
            m_tx_relay->filterInventoryKnown.insert(txid);
        }
    }

    void PushInventory(const CInv &inv) {
        if (inv.type == MSG_TX && m_tx_relay != nullptr) {
            const TxId txid(inv.hash);
            LOCK(m_tx_relay->cs_tx_inventory);
            if (!m_tx_relay->filterInventoryKnown.contains(txid)) {
                m_tx_relay->setInventoryTxToSend.insert(txid);
            }
        } else if (inv.type == MSG_BLOCK) {
            const BlockHash hash(inv.hash);
            LOCK(cs_inventory);
            vInventoryBlockToSend.push_back(hash);
        }
    }

    void PushBlockHash(const BlockHash &hash) {
        LOCK(cs_inventory);
        vBlockHashesToAnnounce.push_back(hash);
    }

    void CloseSocketDisconnect();

    void copyStats(CNodeStats &stats, const std::vector<bool> &m_asmap);

    ServiceFlags GetLocalServices() const { return nLocalServices; }

    std::string GetAddrName() const;
    void MaybeSetAddrName(const std::string &addrNameIn);
};

int64_t PoissonNextSend(int64_t now, int average_interval_seconds);

inline std::chrono::microseconds
PoissonNextSend(std::chrono::microseconds now,
                std::chrono::seconds average_interval) {
    return std::chrono::microseconds{
        PoissonNextSend(now.count(), average_interval.count())};
}

std::string getSubVersionEB(uint64_t MaxBlockSize);
std::string userAgent(const Config &config);

#endif // BITCOIN_NET_H