protocol.h

Go to the documentation of this file.

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 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 __cplusplus
#error This header can only be compiled as C++.
#endif

#ifndef BITCOIN_PROTOCOL_H
#define BITCOIN_PROTOCOL_H

#include <netaddress.h>
#include <primitives/transaction.h>
#include <serialize.h>
#include <streams.h>
#include <uint256.h>
#include <version.h>

#include <limits>
#include <stdint.h>
#include <string>

class CMessageHeader
{
public:
    static constexpr size_t MESSAGE_START_SIZE = 4;
    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 = MESSAGE_START_SIZE + COMMAND_SIZE;
    static constexpr size_t CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE;
    static constexpr size_t HEADER_SIZE = MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;
    typedef unsigned char MessageStartChars[MESSAGE_START_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); }

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

namespace NetMsgType {

extern const char* VERSION;
extern const char* VERACK;
extern const char* ADDR;
extern const char *ADDRV2;
extern const char *SENDADDRV2;
extern const char* INV;
extern const char* GETDATA;
extern const char* MERKLEBLOCK;
extern const char* GETBLOCKS;
extern const char* GETHEADERS;
extern const char* TX;
extern const char* HEADERS;
extern const char* BLOCK;
extern const char* GETADDR;
extern const char* MEMPOOL;
extern const char* PING;
extern const char* PONG;
extern const char* NOTFOUND;
extern const char* FILTERLOAD;
extern const char* FILTERADD;
extern const char* FILTERCLEAR;
extern const char* SENDHEADERS;
extern const char* FEEFILTER;
extern const char* SENDCMPCT;
extern const char* CMPCTBLOCK;
extern const char* GETBLOCKTXN;
extern const char* BLOCKTXN;
extern const char* GETCFILTERS;
extern const char* CFILTER;
extern const char* GETCFHEADERS;
extern const char* CFHEADERS;
extern const char* GETCFCHECKPT;
extern const char* CFCHECKPT;
extern const char* WTXIDRELAY;
}; // namespace NetMsgType

/* Get a vector of all valid message types (see above) */
const std::vector<std::string>& getAllNetMessageTypes();

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.
    // Bitcoin Core nodes used to support this by default, without advertising this bit,
    // but no longer do as of protocol version 70011 (= NO_BLOOM_VERSION)
    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),

    // 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);

ServiceFlags GetDesirableServiceFlags(ServiceFlags services);

void SetServiceFlagsIBDCache(bool status);

static inline bool HasAllDesirableServiceFlags(ServiceFlags services)
{
    return !(GetDesirableServiceFlags(services) & (~services));
}

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

class CAddress : public CService
{
    static constexpr uint32_t 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, uint32_t nTimeIn) : CService{ipIn}, nTime{nTimeIn}, nServices{nServicesIn} {};

    SERIALIZE_METHODS(CAddress, obj)
    {
        // CAddress has a distinct network serialization and a disk serialization, but it should never
        // be hashed (except through CHashWriter in addrdb.cpp, which sets SER_DISK), and it's
        // ambiguous what that would mean. Make sure no code relying on that is introduced:
        assert(!(s.GetType() & SER_GETHASH));
        bool use_v2;
        bool store_time;
        if (s.GetType() & SER_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 (s.GetVersion() & ADDRV2_FORMAT) 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 && (s.GetVersion() & ADDRV2_FORMAT)) {
                // Only support v2 deserialization if ADDRV2_FORMAT is set.
                use_v2 = true;
            } else {
                throw std::ios_base::failure("Unsupported CAddress disk format version");
            }
            store_time = true;
        } else {
            // In the network serialization format, the encoding (v1 or v2) is determined directly by
            // the value of ADDRV2_FORMAT in the stream version, as no explicitly encoded version
            // exists in the stream.
            assert(s.GetType() & SER_NETWORK);
            use_v2 = s.GetVersion() & ADDRV2_FORMAT;
            // The only time we serialize a CAddress object without nTime is in
            // the initial VERSION messages which contain two CAddress records.
            // At that point, the serialization version is INIT_PROTO_VERSION.
            // After the version handshake, serialization version is >=
            // MIN_PEER_PROTO_VERSION and all ADDR messages are serialized with
            // nTime.
            store_time = s.GetVersion() != INIT_PROTO_VERSION;
        }

        SER_READ(obj, obj.nTime = TIME_INIT);
        if (store_time) READWRITE(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.
        OverrideStream<Stream> os(&s, s.GetType(), use_v2 ? ADDRV2_FORMAT : 0);
        SerReadWriteMany(os, ser_action, ReadWriteAsHelper<CService>(obj));
    }

    uint32_t 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