1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present The Bitcoin Core developers
3// Distributed under the MIT software license, see the accompanying
4// file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6#ifndef BITCOIN_PROTOCOL_H
7#define BITCOIN_PROTOCOL_H
8
9#include <kernel/messagestartchars.h> // IWYU pragma: export
10#include <netaddress.h>
11#include <primitives/transaction.h>
12#include <serialize.h>
13#include <streams.h>
14#include <uint256.h>
15#include <util/time.h>
16
17#include <array>
18#include <cstdint>
19#include <limits>
20#include <string>
21
22/** Message header.
23 * (4) message start.
24 * (12) message type.
25 * (4) size.
26 * (4) checksum.
27 */
28class CMessageHeader
29{
30public:
31    static constexpr size_t MESSAGE_TYPE_SIZE = 12;
32    static constexpr size_t MESSAGE_SIZE_SIZE = 4;
33    static constexpr size_t CHECKSUM_SIZE = 4;
34    static constexpr size_t MESSAGE_SIZE_OFFSET = std::tuple_size_v<MessageStartChars> + MESSAGE_TYPE_SIZE;
35    static constexpr size_t CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE;
36    static constexpr size_t HEADER_SIZE = std::tuple_size_v<MessageStartChars> + MESSAGE_TYPE_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;
37
38    explicit CMessageHeader() = default;
39
40    /** Construct a P2P message header from message-start characters, a message type and the size of the message.
41     * @note Passing in a `msg_type` longer than MESSAGE_TYPE_SIZE will result in a run-time assertion error.
42     */
43    CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* msg_type, unsigned int nMessageSizeIn);
44
45    std::string GetMessageType() const;
46    bool IsMessageTypeValid() const;
47
48    SERIALIZE_METHODS(CMessageHeader, obj) { READWRITE(obj.pchMessageStart, obj.m_msg_type, obj.nMessageSize, obj.pchChecksum); }
49
50    MessageStartChars pchMessageStart{};
51    char m_msg_type[MESSAGE_TYPE_SIZE]{};
52    uint32_t nMessageSize{std::numeric_limits<uint32_t>::max()};
53    uint8_t pchChecksum[CHECKSUM_SIZE]{};
54};
55
56/**
57 * Bitcoin protocol message types. When adding new message types, don't forget
58 * to update ALL_NET_MESSAGE_TYPES below.
59 */
60namespace NetMsgType {
61/**
62 * The version message provides information about the transmitting node to the
63 * receiving node at the beginning of a connection.
64 */
65inline constexpr const char* VERSION{"version"};
66/**
67 * The verack message acknowledges a previously-received version message,
68 * informing the connecting node that it can begin to send other messages.
69 */
70inline constexpr const char* VERACK{"verack"};
71/**
72 * The addr (IP address) message relays connection information for peers on the
73 * network.
74 */
75inline constexpr const char* ADDR{"addr"};
76/**
77 * The addrv2 message relays connection information for peers on the network just
78 * like the addr message, but is extended to allow gossiping of longer node
79 * addresses (see BIP155).
80 */
81inline constexpr const char* ADDRV2{"addrv2"};
82/**
83 * The sendaddrv2 message signals support for receiving ADDRV2 messages (BIP155).
84 * It also implies that its sender can encode as ADDRV2 and would send ADDRV2
85 * instead of ADDR to a peer that has signaled ADDRV2 support by sending SENDADDRV2.
86 */
87inline constexpr const char* SENDADDRV2{"sendaddrv2"};
88/**
89 * The inv message (inventory message) transmits one or more inventories of
90 * objects known to the transmitting peer.
91 */
92inline constexpr const char* INV{"inv"};
93/**
94 * The getdata message requests one or more data objects from another node.
95 */
96inline constexpr const char* GETDATA{"getdata"};
97/**
98 * The merkleblock message is a reply to a getdata message which requested a
99 * block using the inventory type MSG_MERKLEBLOCK.
100 * @since protocol version 70001 as described by BIP37.
101 */
102inline constexpr const char* MERKLEBLOCK{"merkleblock"};
103/**
104 * The getblocks message requests an inv message that provides block header
105 * hashes starting from a particular point in the block chain.
106 */
107inline constexpr const char* GETBLOCKS{"getblocks"};
108/**
109 * The getheaders message requests a headers message that provides block
110 * headers starting from a particular point in the block chain.
111 * @since protocol version 31800.
112 */
113inline constexpr const char* GETHEADERS{"getheaders"};
114/**
115 * The tx message transmits a single transaction.
116 */
117inline constexpr const char* TX{"tx"};
118/**
119 * The headers message sends one or more block headers to a node which
120 * previously requested certain headers with a getheaders message.
121 * @since protocol version 31800.
122 */
123inline constexpr const char* HEADERS{"headers"};
124/**
125 * The block message transmits a single serialized block.
126 */
127inline constexpr const char* BLOCK{"block"};
128/**
129 * The getaddr message requests an addr message from the receiving node,
130 * preferably one with lots of IP addresses of other receiving nodes.
131 */
132inline constexpr const char* GETADDR{"getaddr"};
133/**
134 * The mempool message requests the TXIDs of transactions that the receiving
135 * node has verified as valid but which have not yet appeared in a block.
136 * @since protocol version 60002 as described by BIP35.
137 *   Only available with service bit NODE_BLOOM, see also BIP111.
138 */
139inline constexpr const char* MEMPOOL{"mempool"};
140/**
141 * The ping message is sent periodically to help confirm that the receiving
142 * peer is still connected.
143 */
144inline constexpr const char* PING{"ping"};
145/**
146 * The pong message replies to a ping message, proving to the pinging node that
147 * the ponging node is still alive.
148 * @since protocol version 60001 as described by BIP31.
149 */
150inline constexpr const char* PONG{"pong"};
151/**
152 * The notfound message is a reply to a getdata message which requested an
153 * object the receiving node does not have available for relay.
154 * @since protocol version 70001.
155 */
156inline constexpr const char* NOTFOUND{"notfound"};
157/**
158 * The filterload message tells the receiving peer to filter all relayed
159 * transactions and requested merkle blocks through the provided filter.
160 * @since protocol version 70001 as described by BIP37.
161 *   Only available with service bit NODE_BLOOM since protocol version
162 *   70011 as described by BIP111.
163 */
164inline constexpr const char* FILTERLOAD{"filterload"};
165/**
166 * The filteradd message tells the receiving peer to add a single element to a
167 * previously-set bloom filter, such as a new public key.
168 * @since protocol version 70001 as described by BIP37.
169 *   Only available with service bit NODE_BLOOM since protocol version
170 *   70011 as described by BIP111.
171 */
172inline constexpr const char* FILTERADD{"filteradd"};
173/**
174 * The filterclear message tells the receiving peer to remove a previously-set
175 * bloom filter.
176 * @since protocol version 70001 as described by BIP37.
177 *   Only available with service bit NODE_BLOOM since protocol version
178 *   70011 as described by BIP111.
179 */
180inline constexpr const char* FILTERCLEAR{"filterclear"};
181/**
182 * Indicates that a node prefers to receive new block announcements via a
183 * "headers" message rather than an "inv".
184 * @since protocol version 70012 as described by BIP130.
185 */
186inline constexpr const char* SENDHEADERS{"sendheaders"};
187/**
188 * The feefilter message tells the receiving peer not to inv us any txs
189 * which do not meet the specified min fee rate.
190 * @since protocol version 70013 as described by BIP133
191 */
192inline constexpr const char* FEEFILTER{"feefilter"};
193/**
194 * Contains a 1-byte bool and 8-byte LE version number.
195 * Indicates that a node is willing to provide blocks via "cmpctblock" messages.
196 * May indicate that a node prefers to receive new block announcements via a
197 * "cmpctblock" message rather than an "inv", depending on message contents.
198 * @since protocol version 70014 as described by BIP 152
199 */
200inline constexpr const char* SENDCMPCT{"sendcmpct"};
201/**
202 * Contains a CBlockHeaderAndShortTxIDs object - providing a header and
203 * list of "short txids".
204 * @since protocol version 70014 as described by BIP 152
205 */
206inline constexpr const char* CMPCTBLOCK{"cmpctblock"};
207/**
208 * Contains a BlockTransactionsRequest
209 * Peer should respond with "blocktxn" message.
210 * @since protocol version 70014 as described by BIP 152
211 */
212inline constexpr const char* GETBLOCKTXN{"getblocktxn"};
213/**
214 * Contains a BlockTransactions.
215 * Sent in response to a "getblocktxn" message.
216 * @since protocol version 70014 as described by BIP 152
217 */
218inline constexpr const char* BLOCKTXN{"blocktxn"};
219/**
220 * getcfilters requests compact filters for a range of blocks.
221 * Only available with service bit NODE_COMPACT_FILTERS as described by
222 * BIP 157 & 158.
223 */
224inline constexpr const char* GETCFILTERS{"getcfilters"};
225/**
226 * cfilter is a response to a getcfilters request containing a single compact
227 * filter.
228 */
229inline constexpr const char* CFILTER{"cfilter"};
230/**
231 * getcfheaders requests a compact filter header and the filter hashes for a
232 * range of blocks, which can then be used to reconstruct the filter headers
233 * for those blocks.
234 * Only available with service bit NODE_COMPACT_FILTERS as described by
235 * BIP 157 & 158.
236 */
237inline constexpr const char* GETCFHEADERS{"getcfheaders"};
238/**
239 * cfheaders is a response to a getcfheaders request containing a filter header
240 * and a vector of filter hashes for each subsequent block in the requested range.
241 */
242inline constexpr const char* CFHEADERS{"cfheaders"};
243/**
244 * getcfcheckpt requests evenly spaced compact filter headers, enabling
245 * parallelized download and validation of the headers between them.
246 * Only available with service bit NODE_COMPACT_FILTERS as described by
247 * BIP 157 & 158.
248 */
249inline constexpr const char* GETCFCHECKPT{"getcfcheckpt"};
250/**