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 <avalanche/proofid.h>
#include <avalanche/proofradixtreeadapter.h>
#include <bloom.h>
#include <chainparams.h>
#include <compat.h>
#include <consensus/amount.h>
#include <crypto/siphash.h>
#include <hash.h>
#include <i2p.h>
#include <logging.h>
#include <net_permissions.h>
#include <netaddress.h>
#include <nodeid.h>
#include <protocol.h>
#include <pubkey.h>
#include <radix.h>
#include <random.h>
#include <span.h>
#include <streams.h>
#include <sync.h>
#include <threadinterrupt.h>
#include <uint256.h>
#include <util/check.h>
#include <validation.h> // For cs_main
 
#include <atomic>
#include <condition_variable>
#include <cstdint>
#include <deque>
#include <list>
#include <map>
#include <memory>
#include <thread>
#include <vector>
 
class AddrMan;
class BanMan;
class Config;
class CNode;
class CScheduler;
struct bilingual_str;
 
static const bool DEFAULT_WHITELISTRELAY = true;
static const bool DEFAULT_WHITELISTFORCERELAY = false;
 
static constexpr std::chrono::minutes TIMEOUT_INTERVAL{20};
static constexpr auto FEELER_INTERVAL = 2min;
static constexpr auto EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL = 5min;
static const unsigned int MAX_SUBVERSION_LENGTH = 256;
static const int MAX_OUTBOUND_FULL_RELAY_CONNECTIONS = 16;
static const int MAX_ADDNODE_CONNECTIONS = 8;
static const int MAX_BLOCK_RELAY_ONLY_CONNECTIONS = 2;
static const int DEFAULT_MAX_AVALANCHE_OUTBOUND_CONNECTIONS = 300;
static const int MAX_FEELER_CONNECTIONS = 1;
static const bool DEFAULT_LISTEN = true;
static const unsigned int DEFAULT_MAX_PEER_CONNECTIONS = 4096;
static constexpr uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
static const bool DEFAULT_BLOCKSONLY = false;
static const int64_t DEFAULT_PEER_CONNECT_TIMEOUT = 60;
static const int NUM_FDS_MESSAGE_CAPTURE = 1;
 
static const bool DEFAULT_FORCEDNSSEED = false;
static const bool DEFAULT_DNSSEED = true;
static const bool DEFAULT_FIXEDSEEDS = true;
static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
static const size_t DEFAULT_MAXSENDBUFFER = 1 * 1000;
 
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;
};
 
const std::vector<std::string> CONNECTION_TYPE_DOC{
    "outbound-full-relay (default automatic connections)",
    "block-relay-only (does not relay transactions or addresses)",
    "inbound (initiated by the peer)",
    "manual (added via addnode RPC or -addnode/-connect configuration options)",
    "addr-fetch (short-lived automatic connection for soliciting addresses)",
    "feeler (short-lived automatic connection for testing addresses)"};
 
enum class ConnectionType {
    INBOUND,
 
    OUTBOUND_FULL_RELAY,
 
    MANUAL,
 
    FEELER,
 
    BLOCK_RELAY,
 
    ADDR_FETCH,
 
    AVALANCHE_OUTBOUND,
};
 
std::string ConnectionTypeAsString(ConnectionType conn_type);
void Discover();
uint16_t GetListenPort();
 
enum {
    // unknown
    LOCAL_NONE,
    // address a local interface listens on
    LOCAL_IF,
    // address explicit bound to
    LOCAL_BIND,
    // address reported by UPnP or NAT-PMP
    LOCAL_MAPPED,
    // address explicitly specified (-externalip=)
    LOCAL_MANUAL,
 
    LOCAL_MAX
};
 
bool IsPeerAddrLocalGood(CNode *pnode);
std::optional<CAddress> GetLocalAddrForPeer(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;
 
struct LocalServiceInfo {
    int nScore;
    uint16_t 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;
    std::chrono::seconds m_last_send;
    std::chrono::seconds m_last_recv;
    std::chrono::seconds m_last_tx_time;
    std::chrono::seconds m_last_proof_time;
    std::chrono::seconds m_last_block_time;
    std::chrono::seconds m_connected;
    int64_t nTimeOffset;
    std::string m_addr_name;
    int nVersion;
    std::string cleanSubVer;
    bool fInbound;
    bool m_bip152_highbandwidth_to;
    bool m_bip152_highbandwidth_from;
    int m_starting_height;
    uint64_t nSendBytes;
    mapMsgCmdSize mapSendBytesPerMsgCmd;
    uint64_t nRecvBytes;
    mapMsgCmdSize mapRecvBytesPerMsgCmd;
    NetPermissionFlags m_permissionFlags;
    std::chrono::microseconds m_last_ping_time;
    std::chrono::microseconds m_min_ping_time;
    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;
    // Network the peer connected through
    Network m_network;
    uint32_t m_mapped_as;
    ConnectionType m_conn_type;
    std::optional<double> m_availabilityScore;
};
 
class CNetMessage {
public:
    CDataStream m_recv;
    std::chrono::microseconds m_time{0};
    bool m_valid_netmagic = false;
    bool m_valid_header = false;
    bool m_valid_checksum = false;
    uint32_t m_message_size{0};
    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;
    virtual int Read(const Config &config, Span<const uint8_t> &msg_bytes) = 0;
    // decomposes a message from the context
    virtual CNetMessage GetMessage(const Config &config,
                                   std::chrono::microseconds 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, Span<const uint8_t> msg_bytes);
    int readData(Span<const uint8_t> msg_bytes);
 
    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, Span<const uint8_t> &msg_bytes) override {
        int ret = in_data ? readData(msg_bytes) : readHeader(config, msg_bytes);
        if (ret < 0) {
            Reset();
        } else {
            msg_bytes = msg_bytes.subspan(ret);
        }
        return ret;
    }
 
    CNetMessage GetMessage(const Config &config,
                           std::chrono::microseconds 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);
    size_t nSendSize GUARDED_BY(cs_vSend){0};
    size_t nSendOffset GUARDED_BY(cs_vSend){0};
    uint64_t nSendBytes GUARDED_BY(cs_vSend){0};
    std::deque<std::vector<uint8_t>> vSendMsg GUARDED_BY(cs_vSend);
    Mutex cs_vSend;
    Mutex cs_hSocket;
    Mutex cs_vRecv;
 
    RecursiveMutex cs_vProcessMsg;
    std::list<CNetMessage> vProcessMsg GUARDED_BY(cs_vProcessMsg);
    size_t nProcessQueueSize{0};
 
    RecursiveMutex cs_sendProcessing;
 
    uint64_t nRecvBytes GUARDED_BY(cs_vRecv){0};
 
    std::atomic<std::chrono::seconds> m_last_send{0s};
    std::atomic<std::chrono::seconds> m_last_recv{0s};
    const std::chrono::seconds m_connected;
    std::atomic<int64_t> nTimeOffset{0};
    // Address of this peer
    const CAddress addr;
    // Bind address of our side of the connection
    const CAddress addrBind;
    const std::string m_addr_name;
    const bool m_inbound_onion;
    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};
    Mutex m_subver_mutex;
    std::string cleanSubVer GUARDED_BY(m_subver_mutex){};
    // This peer is preferred for eviction.
    bool m_prefer_evict{false};
    bool HasPermission(NetPermissionFlags permission) const {
        return NetPermissions::HasFlag(m_permissionFlags, permission);
    }
    // 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};
    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_FULL_RELAY:
            case ConnectionType::BLOCK_RELAY:
            case ConnectionType::AVALANCHE_OUTBOUND:
                return true;
            case ConnectionType::INBOUND:
            case ConnectionType::MANUAL:
            case ConnectionType::ADDR_FETCH:
            case ConnectionType::FEELER:
                return false;
        } // no default case, so the compiler can warn about missing cases
 
        assert(false);
    }
 
    bool IsFullOutboundConn() const {
        return m_conn_type == ConnectionType::OUTBOUND_FULL_RELAY ||
               m_conn_type == ConnectionType::AVALANCHE_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 IsAvalancheOutboundConnection() const {
        return m_conn_type == ConnectionType::AVALANCHE_OUTBOUND;
    }
 
    bool ExpectServicesFromConn() const {
        switch (m_conn_type) {
            case ConnectionType::INBOUND:
            case ConnectionType::MANUAL:
            case ConnectionType::FEELER:
                return false;
            case ConnectionType::OUTBOUND_FULL_RELAY:
            case ConnectionType::BLOCK_RELAY:
            case ConnectionType::ADDR_FETCH:
            case ConnectionType::AVALANCHE_OUTBOUND:
                return true;
        } // no default case, so the compiler can warn about missing cases
 
        assert(false);
    }
 
    Network ConnectedThroughNetwork() const;
 
    // We selected peer as (compact blocks) high-bandwidth peer (BIP152)
    std::atomic<bool> m_bip152_highbandwidth_to{false};
    // Peer selected us as (compact blocks) high-bandwidth peer (BIP152)
    std::atomic<bool> m_bip152_highbandwidth_from{false};
 
    struct TxRelay {
        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){nullptr};
 
        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 GUARDED_BY(cs_tx_inventory);
        // 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{0s};
        std::chrono::microseconds nNextInvSend{0};
 
        std::atomic<Amount> minFeeFilter{Amount::zero()};
        Amount lastSentFeeFilter{Amount::zero()};
        std::chrono::microseconds m_next_send_feefilter{0};
    };
 
    // m_tx_relay == nullptr if we're not relaying transactions with this peer
    const std::unique_ptr<TxRelay> m_tx_relay;
 
    struct ProofRelay {
        mutable RecursiveMutex cs_proof_inventory;
        std::set<avalanche::ProofId>
            setInventoryProofToSend GUARDED_BY(cs_proof_inventory);
        // Prevent sending proof invs if the peer already knows about them
        CRollingBloomFilter filterProofKnown GUARDED_BY(cs_proof_inventory){
            10000, 0.000001};
        std::chrono::microseconds nextInvSend{0};
 
        RadixTree<const avalanche::Proof, avalanche::ProofRadixTreeAdapter>
            sharedProofs;
        std::atomic<std::chrono::seconds> lastSharedProofsUpdate{0s};
        std::atomic<bool> compactproofs_requested{false};
    };
 
    // m_proof_relay == nullptr if we're not relaying proofs with this peer
    const std::unique_ptr<ProofRelay> m_proof_relay;
 
    // True if we know this peer is using Avalanche (at least polling)
    std::atomic<bool> m_avalanche_enabled{false};
 
    mutable Mutex cs_avalanche_pubkey;
    // Pubkey used to verify signatures on Avalanche messages from this peer
    std::optional<CPubKey> m_avalanche_pubkey GUARDED_BY(cs_avalanche_pubkey);
 
    void invsPolled(uint32_t count);
 
    void invsVoted(uint32_t count);
 
    void updateAvailabilityScore(double decayFactor);
    double getAvailabilityScore() const;
 
    // Store the next time we will consider a getavaaddr message from this peer
    std::chrono::seconds m_nextGetAvaAddr{0};
 
    std::atomic<std::chrono::seconds> m_last_block_time{0s};
 
    std::atomic<std::chrono::seconds> m_last_tx_time{0s};
 
    std::atomic<std::chrono::seconds> m_last_proof_time{0s};
 
    std::atomic<std::chrono::microseconds> m_last_ping_time{0us};
 
    std::atomic<std::chrono::microseconds> m_min_ping_time{
        std::chrono::microseconds::max()};
 
    CNode(NodeId id, ServiceFlags nLocalServicesIn, 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, bool inbound_onion);
    ~CNode();
    CNode(const CNode &) = delete;
    CNode &operator=(const CNode &) = delete;
 
    void PongReceived(std::chrono::microseconds ping_time) {
        m_last_ping_time = ping_time;
        m_min_ping_time = std::min(m_min_ping_time.load(), ping_time);
    }
 
    NodeId GetId() const { return id; }
 
    uint64_t GetLocalNonce() const { return nLocalHostNonce; }
    uint64_t GetLocalExtraEntropy() const { return nLocalExtraEntropy; }
 
    int GetRefCount() const {
        assert(nRefCount >= 0);
        return nRefCount;
    }
 
    bool ReceiveMsgBytes(const Config &config, Span<const uint8_t> msg_bytes,
                         bool &complete);
 
    void SetCommonVersion(int greatest_common_version) {
        Assume(m_greatest_common_version == INIT_PROTO_VERSION);
        m_greatest_common_version = greatest_common_version;
    }
    int GetCommonVersion() const { return m_greatest_common_version; }
 
    CService GetAddrLocal() const;
    void SetAddrLocal(const CService &addrLocalIn);
 
    CNode *AddRef() {
        nRefCount++;
        return this;
    }
 
    void Release() { nRefCount--; }
 
    void AddKnownTx(const TxId &txid) {
        if (m_tx_relay != nullptr) {
            LOCK(m_tx_relay->cs_tx_inventory);
            m_tx_relay->filterInventoryKnown.insert(txid);
        }
    }
 
    void PushTxInventory(const TxId &txid) {
        if (m_tx_relay == nullptr) {
            return;
        }
        LOCK(m_tx_relay->cs_tx_inventory);
        if (!m_tx_relay->filterInventoryKnown.contains(txid)) {
            m_tx_relay->setInventoryTxToSend.insert(txid);
        }
    }
 
    void AddKnownProof(const avalanche::ProofId &proofid) {
        if (m_proof_relay != nullptr) {
            LOCK(m_proof_relay->cs_proof_inventory);
            m_proof_relay->filterProofKnown.insert(proofid);
        }
    }
 
    void PushProofInventory(const avalanche::ProofId &proofid) {
        if (m_proof_relay == nullptr) {
            return;
        }
 
        LOCK(m_proof_relay->cs_proof_inventory);
        if (!m_proof_relay->filterProofKnown.contains(proofid)) {
            m_proof_relay->setInventoryProofToSend.insert(proofid);
        }
    }
 
    void CloseSocketDisconnect();
 
    void copyStats(CNodeStats &stats);
 
    ServiceFlags GetLocalServices() const { return nLocalServices; }
 
    std::string ConnectionTypeAsString() const {
        return ::ConnectionTypeAsString(m_conn_type);
    }
 
private:
    const NodeId id;
    const uint64_t nLocalHostNonce;
    const uint64_t nLocalExtraEntropy;
    const ConnectionType m_conn_type;
    std::atomic<int> m_greatest_common_version{INIT_PROTO_VERSION};
 
    const ServiceFlags nLocalServices;
 
    NetPermissionFlags m_permissionFlags{NetPermissionFlags::None};
    // Used only by SocketHandler thread
    std::list<CNetMessage> vRecvMsg;
 
    // Our address, as reported by the peer
    mutable RecursiveMutex cs_addrLocal;
    CService addrLocal GUARDED_BY(cs_addrLocal);
 
    std::atomic<uint64_t> invCounters{0};
 
    std::atomic<double> availabilityScore{0.};
 
    mapMsgCmdSize mapSendBytesPerMsgCmd GUARDED_BY(cs_vSend);
    mapMsgCmdSize mapRecvBytesPerMsgCmd GUARDED_BY(cs_vRecv);
};
 
class NetEventsInterface {
public:
    virtual void InitializeNode(const Config &config, CNode *pnode) = 0;
 
    virtual void FinalizeNode(const Config &config, const CNode &node) = 0;
 
    virtual bool ProcessMessages(const Config &config, CNode *pnode,
                                 std::atomic<bool> &interrupt) = 0;
 
    virtual bool SendMessages(const Config &config, CNode *pnode)
        EXCLUSIVE_LOCKS_REQUIRED(pnode->cs_sendProcessing) = 0;
 
protected:
    ~NetEventsInterface() = default;
};
 
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 m_max_avalanche_outbound = 0;
        int nMaxAddnode = 0;
        int nMaxFeeler = 0;
        CClientUIInterface *uiInterface = nullptr;
        std::vector<NetEventsInterface *> m_msgproc;
        BanMan *m_banman = nullptr;
        unsigned int nSendBufferMaxSize = 0;
        unsigned int nReceiveFloodSize = 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;
        std::vector<CService> onion_binds;
        bool bind_on_any;
        bool m_use_addrman_outgoing = true;
        std::vector<std::string> m_specified_outgoing;
        std::vector<std::string> m_added_nodes;
        bool m_i2p_accept_incoming = true;
    };
 
    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_avalanche_outbound = connOptions.m_max_avalanche_outbound;
            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 +
                             m_max_avalanche_outbound;
        }
        m_client_interface = connOptions.uiInterface;
        m_banman = connOptions.m_banman;
        m_msgproc = connOptions.m_msgproc;
        nSendBufferMaxSize = connOptions.nSendBufferMaxSize;
        nReceiveFloodSize = connOptions.nReceiveFloodSize;
        m_peer_connect_timeout =
            std::chrono::seconds{connOptions.m_peer_connect_timeout};
        {
            LOCK(cs_totalBytesSent);
            nMaxOutboundLimit = connOptions.nMaxOutboundLimit;
        }
        vWhitelistedRange = connOptions.vWhitelistedRange;
        {
            LOCK(m_added_nodes_mutex);
            m_added_nodes = connOptions.m_added_nodes;
        }
        m_onion_binds = connOptions.onion_binds;
    }
 
    CConnman(const Config &configIn, uint64_t seed0, uint64_t seed1,
             AddrMan &addrmanIn, bool network_active = true);
    ~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,
                               const char *strDest, ConnectionType conn_type);
    bool CheckIncomingNonce(uint64_t nonce);
 
    bool ForNode(NodeId id, std::function<bool(CNode *pnode)> func);
 
    void PushMessage(CNode *pnode, CSerializedNetMsg &&msg);
 
    using NodeFn = std::function<void(CNode *)>;
    void ForEachNode(const NodeFn &func) {
        LOCK(m_nodes_mutex);
        for (auto &&node : m_nodes) {
            if (NodeFullyConnected(node)) {
                func(node);
            }
        }
    };
 
    void ForEachNode(const NodeFn &func) const {
        LOCK(m_nodes_mutex);
        for (auto &&node : m_nodes) {
            if (NodeFullyConnected(node)) {
                func(node);
            }
        }
    };
 
    // Addrman functions
    std::vector<CAddress> GetAddresses(size_t max_addresses, size_t max_pct,
                                       std::optional<Network> network) const;
    std::vector<CAddress> GetAddresses(CNode &requestor, size_t max_addresses,
                                       size_t max_pct);
 
    // 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() const;
 
    void StartExtraBlockRelayPeers() {
        LogPrint(BCLog::NET, "net: enabling extra block-relay-only peers\n");
        m_start_extra_block_relay_peers = true;
    }
 
    // 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 GetExtraFullOutboundCount() const;
    // Count the number of block-relay-only peers we have over our limit.
    int GetExtraBlockRelayCount() const;
 
    bool AddNode(const std::string &node);
    bool RemoveAddedNode(const std::string &node);
    std::vector<AddedNodeInfo> GetAddedNodeInfo() const;
 
    bool AddConnection(const std::string &address, ConnectionType conn_type);
 
    size_t GetNodeCount(NumConnections num) const;
    void GetNodeStats(std::vector<CNodeStats> &vstats) const;
    bool DisconnectNode(const std::string &node);
    bool DisconnectNode(const CSubNet &subnet);
    bool DisconnectNode(const CNetAddr &addr);
    bool DisconnectNode(NodeId id);
 
    ServiceFlags GetLocalServices() const;
 
    uint64_t GetMaxOutboundTarget() const;
    std::chrono::seconds GetMaxOutboundTimeframe() const;
 
    bool OutboundTargetReached(bool historicalBlockServingLimit) const;
 
    uint64_t GetOutboundTargetBytesLeft() const;
 
    std::chrono::seconds GetMaxOutboundTimeLeftInCycle() const;
 
    uint64_t GetTotalBytesRecv() const;
    uint64_t GetTotalBytesSent() const;
 
    CSipHasher GetDeterministicRandomizer(uint64_t id) const;
 
    unsigned int GetReceiveFloodSize() const;
 
    void WakeMessageHandler();
 
    std::chrono::microseconds
    PoissonNextSendInbound(std::chrono::microseconds now,
                           std::chrono::seconds average_interval);
 
    bool ShouldRunInactivityChecks(const CNode &node,
                                   std::chrono::seconds now) const;
 
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 Options &options);
 
    void ThreadOpenAddedConnections();
    void AddAddrFetch(const std::string &strDest);
    void ProcessAddrFetch();
    void
    ThreadOpenConnections(std::vector<std::string> connect,
                          std::function<void(const CAddress &, ConnectionType)>
                              mockOpenConnection);
    void ThreadMessageHandler();
    void ThreadI2PAcceptIncoming();
    void AcceptConnection(const ListenSocket &hListenSocket);
 
    void CreateNodeFromAcceptedSocket(SOCKET hSocket,
                                      NetPermissionFlags permissionFlags,
                                      const CAddress &addr_bind,
                                      const CAddress &addr);
 
    void DisconnectNodes();
    void NotifyNumConnectionsChanged();
    bool InactivityCheck(const CNode &node) const;
    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 AlreadyConnectedToAddress(const CAddress &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 &node) const
        EXCLUSIVE_LOCKS_REQUIRED(node.cs_vSend);
    void DumpAddresses();
 
    // Network stats
    void RecordBytesRecv(uint64_t bytes);
    void RecordBytesSent(uint64_t bytes);
 
    std::vector<CAddress> GetCurrentBlockRelayOnlyConns() const;
 
    // Whether the node should be passed out in ForEach* callbacks
    static bool NodeFullyConnected(const CNode *pnode);
 
    const Config *config;
 
    // Network usage totals
    mutable RecursiveMutex cs_totalBytesSent;
    std::atomic<uint64_t> nTotalBytesRecv{0};
    uint64_t nTotalBytesSent GUARDED_BY(cs_totalBytesSent){0};
 
    // outbound limit & stats
    uint64_t nMaxOutboundTotalBytesSentInCycle GUARDED_BY(cs_totalBytesSent){0};
    std::chrono::seconds
        nMaxOutboundCycleStartTime GUARDED_BY(cs_totalBytesSent){0};
    uint64_t nMaxOutboundLimit GUARDED_BY(cs_totalBytesSent);
 
    // P2P timeout in seconds
    std::chrono::seconds 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};
    AddrMan &addrman;
    std::deque<std::string> m_addr_fetches GUARDED_BY(m_addr_fetches_mutex);
    Mutex m_addr_fetches_mutex;
    std::vector<std::string> m_added_nodes GUARDED_BY(m_added_nodes_mutex);
    mutable Mutex m_added_nodes_mutex;
    std::vector<CNode *> m_nodes GUARDED_BY(m_nodes_mutex);
    std::list<CNode *> m_nodes_disconnected;
    mutable RecursiveMutex m_nodes_mutex;
    std::atomic<NodeId> nLastNodeId{0};
    unsigned int nPrevNodeCount{0};
 
    struct CachedAddrResponse {
        std::vector<CAddress> m_addrs_response_cache;
        std::chrono::microseconds m_cache_entry_expiration{0};
    };
 
    std::map<uint64_t, CachedAddrResponse> m_addr_response_caches;
 
    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;
 
    // How many avalanche enabled outbound peers we want
    int m_max_avalanche_outbound;
 
    int nMaxAddnode;
    int nMaxFeeler;
    int m_max_outbound;
    bool m_use_addrman_outgoing;
    CClientUIInterface *m_client_interface;
    // FIXME m_msgproc is a terrible name
    std::vector<NetEventsInterface *> m_msgproc;
    BanMan *m_banman;
 
    std::vector<CAddress> m_anchors;
 
    const uint64_t nSeed0, nSeed1;
 
    bool fMsgProcWake GUARDED_BY(mutexMsgProc);
 
    std::condition_variable condMsgProc;
    Mutex mutexMsgProc;
    std::atomic<bool> flagInterruptMsgProc{false};
 
    CThreadInterrupt interruptNet;
 
    std::unique_ptr<i2p::sam::Session> m_i2p_sam_session;
 
    std::thread threadDNSAddressSeed;
    std::thread threadSocketHandler;
    std::thread threadOpenAddedConnections;
    std::thread threadOpenConnections;
    std::thread threadMessageHandler;
    std::thread threadI2PAcceptIncoming;
 
    std::atomic_bool m_try_another_outbound_peer;
 
    std::atomic_bool m_start_extra_block_relay_peers{false};
 
    std::atomic<std::chrono::microseconds> m_next_send_inv_to_incoming{0us};
 
    std::vector<CService> m_onion_binds;
 
    friend struct ::CConnmanTest;
    friend struct ConnmanTestMsg;
};
 
std::chrono::microseconds
PoissonNextSend(std::chrono::microseconds now,
                std::chrono::seconds average_interval);
 
std::string getSubVersionEB(uint64_t MaxBlockSize);
std::string userAgent(const Config &config);
 
void CaptureMessage(const CAddress &addr, const std::string &msg_type,
                    const Span<const uint8_t> &data, bool is_incoming);
 
struct NodeEvictionCandidate {
    NodeId id;
    std::chrono::seconds m_connected;
    std::chrono::microseconds m_min_ping_time;
    std::chrono::seconds m_last_block_time;
    std::chrono::seconds m_last_proof_time;
    std::chrono::seconds m_last_tx_time;
    bool fRelevantServices;
    bool fRelayTxes;
    bool fBloomFilter;
    uint64_t nKeyedNetGroup;
    bool prefer_evict;
    bool m_is_local;
    Network m_network;
    double availabilityScore;
};
 
[[nodiscard]] std::optional<NodeId>
SelectNodeToEvict(std::vector<NodeEvictionCandidate> &&vEvictionCandidates);
 
void ProtectEvictionCandidatesByRatio(
    std::vector<NodeEvictionCandidate> &vEvictionCandidates);
 
#endif // BITCOIN_NET_H