protocol.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_PROTOCOL_H
#define BITCOIN_PROTOCOL_H

#include <kernel/messagestartchars.h> // IWYU pragma: export
#include <netaddress.h>
#include <primitives/transaction.h>
#include <serialize.h>
#include <streams.h>
#include <uint256.h>
#include <util/time.h>

#include <array>
#include <cstdint>
#include <limits>
#include <string>

class CMessageHeader
{
public:
    static constexpr size_t COMMAND_SIZE = 12;
    static constexpr size_t MESSAGE_SIZE_SIZE = 4;
    static constexpr size_t CHECKSUM_SIZE = 4;
    static constexpr size_t MESSAGE_SIZE_OFFSET = std::tuple_size_v<MessageStartChars> + COMMAND_SIZE;
    static constexpr size_t CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE;
    static constexpr size_t HEADER_SIZE = std::tuple_size_v<MessageStartChars> + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;

    explicit CMessageHeader() = default;

    CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn);

    std::string GetCommand() const;
    bool IsCommandValid() const;

    SERIALIZE_METHODS(CMessageHeader, obj) { READWRITE(obj.pchMessageStart, obj.pchCommand, obj.nMessageSize, obj.pchChecksum); }

    MessageStartChars pchMessageStart{};
    char pchCommand[COMMAND_SIZE]{};
    uint32_t nMessageSize{std::numeric_limits<uint32_t>::max()};
    uint8_t pchChecksum[CHECKSUM_SIZE]{};
};

namespace NetMsgType {
inline constexpr const char* VERSION{"version"};
inline constexpr const char* VERACK{"verack"};
inline constexpr const char* ADDR{"addr"};
inline constexpr const char* ADDRV2{"addrv2"};
inline constexpr const char* SENDADDRV2{"sendaddrv2"};
inline constexpr const char* INV{"inv"};
inline constexpr const char* GETDATA{"getdata"};
inline constexpr const char* MERKLEBLOCK{"merkleblock"};
inline constexpr const char* GETBLOCKS{"getblocks"};
inline constexpr const char* GETHEADERS{"getheaders"};
inline constexpr const char* TX{"tx"};
inline constexpr const char* HEADERS{"headers"};
inline constexpr const char* BLOCK{"block"};
inline constexpr const char* GETADDR{"getaddr"};
inline constexpr const char* MEMPOOL{"mempool"};
inline constexpr const char* PING{"ping"};
inline constexpr const char* PONG{"pong"};
inline constexpr const char* NOTFOUND{"notfound"};
inline constexpr const char* FILTERLOAD{"filterload"};
inline constexpr const char* FILTERADD{"filteradd"};
inline constexpr const char* FILTERCLEAR{"filterclear"};
inline constexpr const char* SENDHEADERS{"sendheaders"};
inline constexpr const char* FEEFILTER{"feefilter"};
inline constexpr const char* SENDCMPCT{"sendcmpct"};
inline constexpr const char* CMPCTBLOCK{"cmpctblock"};
inline constexpr const char* GETBLOCKTXN{"getblocktxn"};
inline constexpr const char* BLOCKTXN{"blocktxn"};
inline constexpr const char* GETCFILTERS{"getcfilters"};
inline constexpr const char* CFILTER{"cfilter"};
inline constexpr const char* GETCFHEADERS{"getcfheaders"};
inline constexpr const char* CFHEADERS{"cfheaders"};
inline constexpr const char* GETCFCHECKPT{"getcfcheckpt"};
inline constexpr const char* CFCHECKPT{"cfcheckpt"};
inline constexpr const char* WTXIDRELAY{"wtxidrelay"};
inline constexpr const char* SENDTXRCNCL{"sendtxrcncl"};
}; // namespace NetMsgType

inline const std::array ALL_NET_MESSAGE_TYPES{std::to_array<std::string>({
    NetMsgType::VERSION,
    NetMsgType::VERACK,
    NetMsgType::ADDR,
    NetMsgType::ADDRV2,
    NetMsgType::SENDADDRV2,
    NetMsgType::INV,
    NetMsgType::GETDATA,
    NetMsgType::MERKLEBLOCK,
    NetMsgType::GETBLOCKS,
    NetMsgType::GETHEADERS,
    NetMsgType::TX,
    NetMsgType::HEADERS,
    NetMsgType::BLOCK,
    NetMsgType::GETADDR,
    NetMsgType::MEMPOOL,
    NetMsgType::PING,
    NetMsgType::PONG,
    NetMsgType::NOTFOUND,
    NetMsgType::FILTERLOAD,
    NetMsgType::FILTERADD,
    NetMsgType::FILTERCLEAR,
    NetMsgType::SENDHEADERS,
    NetMsgType::FEEFILTER,
    NetMsgType::SENDCMPCT,
    NetMsgType::CMPCTBLOCK,
    NetMsgType::GETBLOCKTXN,
    NetMsgType::BLOCKTXN,
    NetMsgType::GETCFILTERS,
    NetMsgType::CFILTER,
    NetMsgType::GETCFHEADERS,
    NetMsgType::CFHEADERS,
    NetMsgType::GETCFCHECKPT,
    NetMsgType::CFCHECKPT,
    NetMsgType::WTXIDRELAY,
    NetMsgType::SENDTXRCNCL,
})};

enum ServiceFlags : uint64_t {
    // NOTE: When adding here, be sure to update serviceFlagToStr too
    // Nothing
    NODE_NONE = 0,
    // NODE_NETWORK means that the node is capable of serving the complete block chain. It is currently
    // set by all Bitcoin Core non pruned nodes, and is unset by SPV clients or other light clients.
    NODE_NETWORK = (1 << 0),
    // NODE_BLOOM means the node is capable and willing to handle bloom-filtered connections.
    NODE_BLOOM = (1 << 2),
    // NODE_WITNESS indicates that a node can be asked for blocks and transactions including
    // witness data.
    NODE_WITNESS = (1 << 3),
    // NODE_COMPACT_FILTERS means the node will service basic block filter requests.
    // See BIP157 and BIP158 for details on how this is implemented.
    NODE_COMPACT_FILTERS = (1 << 6),
    // NODE_NETWORK_LIMITED means the same as NODE_NETWORK with the limitation of only
    // serving the last 288 (2 day) blocks
    // See BIP159 for details on how this is implemented.
    NODE_NETWORK_LIMITED = (1 << 10),

    // NODE_P2P_V2 means the node supports BIP324 transport
    NODE_P2P_V2 = (1 << 11),

    // Bits 24-31 are reserved for temporary experiments. Just pick a bit that
    // isn't getting used, or one not being used much, and notify the
    // bitcoin-development mailing list. Remember that service bits are just
    // unauthenticated advertisements, so your code must be robust against
    // collisions and other cases where nodes may be advertising a service they
    // do not actually support. Other service bits should be allocated via the
    // BIP process.
};

std::vector<std::string> serviceFlagsToStr(uint64_t flags);

constexpr ServiceFlags SeedsServiceFlags() { return ServiceFlags(NODE_NETWORK | NODE_WITNESS); }

static inline bool MayHaveUsefulAddressDB(ServiceFlags services)
{
    return (services & NODE_NETWORK) || (services & NODE_NETWORK_LIMITED);
}

class CAddress : public CService
{
    static constexpr std::chrono::seconds TIME_INIT{100000000};

    static constexpr uint32_t DISK_VERSION_INIT{220000};
    static constexpr uint32_t DISK_VERSION_IGNORE_MASK{0b00000000'00000111'11111111'11111111};
    static constexpr uint32_t DISK_VERSION_ADDRV2{1 << 29};
    static_assert((DISK_VERSION_INIT & ~DISK_VERSION_IGNORE_MASK) == 0, "DISK_VERSION_INIT must be covered by DISK_VERSION_IGNORE_MASK");
    static_assert((DISK_VERSION_ADDRV2 & DISK_VERSION_IGNORE_MASK) == 0, "DISK_VERSION_ADDRV2 must not be covered by DISK_VERSION_IGNORE_MASK");

public:
    CAddress() : CService{} {};
    CAddress(CService ipIn, ServiceFlags nServicesIn) : CService{ipIn}, nServices{nServicesIn} {};
    CAddress(CService ipIn, ServiceFlags nServicesIn, NodeSeconds time) : CService{ipIn}, nTime{time}, nServices{nServicesIn} {};

    enum class Format {
        Disk,
        Network,
    };
    struct SerParams : CNetAddr::SerParams {
        const Format fmt;
        SER_PARAMS_OPFUNC
    };
    static constexpr SerParams V1_NETWORK{{CNetAddr::Encoding::V1}, Format::Network};
    static constexpr SerParams V2_NETWORK{{CNetAddr::Encoding::V2}, Format::Network};
    static constexpr SerParams V1_DISK{{CNetAddr::Encoding::V1}, Format::Disk};
    static constexpr SerParams V2_DISK{{CNetAddr::Encoding::V2}, Format::Disk};

    SERIALIZE_METHODS(CAddress, obj)
    {
        bool use_v2;
        auto& params = SER_PARAMS(SerParams);
        if (params.fmt == Format::Disk) {
            // In the disk serialization format, the encoding (v1 or v2) is determined by a flag version
            // that's part of the serialization itself. ADDRV2_FORMAT in the stream version only determines
            // whether V2 is chosen/permitted at all.
            uint32_t stored_format_version = DISK_VERSION_INIT;
            if (params.enc == Encoding::V2) stored_format_version |= DISK_VERSION_ADDRV2;
            READWRITE(stored_format_version);
            stored_format_version &= ~DISK_VERSION_IGNORE_MASK; // ignore low bits
            if (stored_format_version == 0) {
                use_v2 = false;
            } else if (stored_format_version == DISK_VERSION_ADDRV2 && params.enc == Encoding::V2) {
                // Only support v2 deserialization if V2 is set.
                use_v2 = true;
            } else {
                throw std::ios_base::failure("Unsupported CAddress disk format version");
            }
        } else {
            assert(params.fmt == Format::Network);
            // In the network serialization format, the encoding (v1 or v2) is determined directly by
            // the value of enc in the stream params, as no explicitly encoded version
            // exists in the stream.
            use_v2 = params.enc == Encoding::V2;
        }

        READWRITE(Using<LossyChronoFormatter<uint32_t>>(obj.nTime));
        // nServices is serialized as CompactSize in V2; as uint64_t in V1.
        if (use_v2) {
            uint64_t services_tmp;
            SER_WRITE(obj, services_tmp = obj.nServices);
            READWRITE(Using<CompactSizeFormatter<false>>(services_tmp));
            SER_READ(obj, obj.nServices = static_cast<ServiceFlags>(services_tmp));
        } else {
            READWRITE(Using<CustomUintFormatter<8>>(obj.nServices));
        }
        // Invoke V1/V2 serializer for CService parent object.
        const auto ser_params{use_v2 ? CNetAddr::V2 : CNetAddr::V1};
        READWRITE(ser_params(AsBase<CService>(obj)));
    }

    NodeSeconds nTime{TIME_INIT};
    ServiceFlags nServices{NODE_NONE};

    friend bool operator==(const CAddress& a, const CAddress& b)
    {
        return a.nTime == b.nTime &&
               a.nServices == b.nServices &&
               static_cast<const CService&>(a) == static_cast<const CService&>(b);
    }
};

const uint32_t MSG_WITNESS_FLAG = 1 << 30;
const uint32_t MSG_TYPE_MASK = 0xffffffff >> 2;

enum GetDataMsg : uint32_t {
    UNDEFINED = 0,
    MSG_TX = 1,
    MSG_BLOCK = 2,
    MSG_WTX = 5,                                      
    // The following can only occur in getdata. Invs always use TX/WTX or BLOCK.
    MSG_FILTERED_BLOCK = 3,                           
    MSG_CMPCT_BLOCK = 4,                              
    MSG_WITNESS_BLOCK = MSG_BLOCK | MSG_WITNESS_FLAG, 
    MSG_WITNESS_TX = MSG_TX | MSG_WITNESS_FLAG,       
    // MSG_FILTERED_WITNESS_BLOCK is defined in BIP144 as reserved for future
    // use and remains unused.
    // MSG_FILTERED_WITNESS_BLOCK = MSG_FILTERED_BLOCK | MSG_WITNESS_FLAG,
};

class CInv
{
public:
    CInv();
    CInv(uint32_t typeIn, const uint256& hashIn);

    SERIALIZE_METHODS(CInv, obj) { READWRITE(obj.type, obj.hash); }

    friend bool operator<(const CInv& a, const CInv& b);

    std::string GetCommand() const;
    std::string ToString() const;

    // Single-message helper methods
    bool IsMsgTx() const { return type == MSG_TX; }
    bool IsMsgBlk() const { return type == MSG_BLOCK; }
    bool IsMsgWtx() const { return type == MSG_WTX; }
    bool IsMsgFilteredBlk() const { return type == MSG_FILTERED_BLOCK; }
    bool IsMsgCmpctBlk() const { return type == MSG_CMPCT_BLOCK; }
    bool IsMsgWitnessBlk() const { return type == MSG_WITNESS_BLOCK; }

    // Combined-message helper methods
    bool IsGenTxMsg() const
    {
        return type == MSG_TX || type == MSG_WTX || type == MSG_WITNESS_TX;
    }
    bool IsGenBlkMsg() const
    {
        return type == MSG_BLOCK || type == MSG_FILTERED_BLOCK || type == MSG_CMPCT_BLOCK || type == MSG_WITNESS_BLOCK;
    }

    uint32_t type;
    uint256 hash;
};

GenTxid ToGenTxid(const CInv& inv);

#endif // BITCOIN_PROTOCOL_H