protocol.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2019 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 <serialize.h>
#include <uint256.h>
#include <version.h>

#include <atomic>
#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(const MessageStartChars& pchMessageStartIn);
    CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn);

    std::string GetCommand() const;
    bool IsValid(const MessageStartChars& messageStart) const;

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action)
    {
        READWRITE(pchMessageStart);
        READWRITE(pchCommand);
        READWRITE(nMessageSize);
        READWRITE(pchChecksum);
    }

    char pchMessageStart[MESSAGE_START_SIZE];
    char pchCommand[COMMAND_SIZE];
    uint32_t nMessageSize;
    uint8_t pchChecksum[CHECKSUM_SIZE];
};

namespace NetMsgType {

extern const char *VERSION;
extern const char *VERACK;
extern const char *ADDR;
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 *REJECT;
extern const char *SENDHEADERS;
extern const char *FEEFILTER;
extern const char *SENDCMPCT;
extern const char *CMPCTBLOCK;
extern const char *GETBLOCKTXN;
extern const char *BLOCKTXN;
};

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

enum ServiceFlags : uint64_t {
    // 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_GETUTXO means the node is capable of responding to the getutxo protocol request.
    // Bitcoin Core does not support this but a patch set called Bitcoin XT does.
    // See BIP 64 for details on how this is implemented.
    NODE_GETUTXO = (1 << 1),
    // 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_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.
};

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
{
public:
    CAddress();
    explicit CAddress(CService ipIn, ServiceFlags nServicesIn);

    void Init();

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action)
    {
        if (ser_action.ForRead())
            Init();
        int nVersion = s.GetVersion();
        if (s.GetType() & SER_DISK)
            READWRITE(nVersion);
        if ((s.GetType() & SER_DISK) ||
            (nVersion >= CADDR_TIME_VERSION && !(s.GetType() & SER_GETHASH)))
            READWRITE(nTime);
        uint64_t nServicesInt = nServices;
        READWRITE(nServicesInt);
        nServices = static_cast<ServiceFlags>(nServicesInt);
        READWRITEAS(CService, *this);
    }

    // TODO: make private (improves encapsulation)
public:
    ServiceFlags nServices;

    // disk and network only
    unsigned int nTime;
};

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

enum GetDataMsg
{
    UNDEFINED = 0,
    MSG_TX = 1,
    MSG_BLOCK = 2,
    // The following can only occur in getdata. Invs always use TX 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 = MSG_FILTERED_BLOCK | MSG_WITNESS_FLAG,
};

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

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action)
    {
        READWRITE(type);
        READWRITE(hash);
    }

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

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

public:
    int type;
    uint256 hash;
};

#endif // BITCOIN_PROTOCOL_H