Bitcoin Core  26.99.0
P2P Digital Currency
headerssync.h
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1 // Copyright (c) 2022 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #ifndef BITCOIN_HEADERSSYNC_H
6 #define BITCOIN_HEADERSSYNC_H
7 
8 #include <arith_uint256.h>
9 #include <chain.h>
10 #include <consensus/params.h>
11 #include <net.h> // For NodeId
12 #include <primitives/block.h>
13 #include <uint256.h>
14 #include <util/bitdeque.h>
15 #include <util/hasher.h>
16 
17 #include <deque>
18 #include <vector>
19 
20 // A compressed CBlockHeader, which leaves out the prevhash
22  // header
23  int32_t nVersion{0};
25  uint32_t nTime{0};
26  uint32_t nBits{0};
27  uint32_t nNonce{0};
28 
30  {
32  }
33 
35  {
36  nVersion = header.nVersion;
38  nTime = header.nTime;
39  nBits = header.nBits;
40  nNonce = header.nNonce;
41  }
42 
43  CBlockHeader GetFullHeader(const uint256& hash_prev_block) {
45  ret.nVersion = nVersion;
46  ret.hashPrevBlock = hash_prev_block;
47  ret.hashMerkleRoot = hashMerkleRoot;
48  ret.nTime = nTime;
49  ret.nBits = nBits;
50  ret.nNonce = nNonce;
51  return ret;
52  };
53 };
54 
102 public:
104 
105  enum class State {
109  PRESYNC,
113  REDOWNLOAD,
115  FINAL
116  };
117 
119  State GetState() const { return m_download_state; }
120 
122  int64_t GetPresyncHeight() const { return m_current_height; }
123 
125  uint32_t GetPresyncTime() const { return m_last_header_received.nTime; }
126 
129 
138  HeadersSyncState(NodeId id, const Consensus::Params& consensus_params,
139  const CBlockIndex* chain_start, const arith_uint256& minimum_required_work);
140 
143  std::vector<CBlockHeader> pow_validated_headers;
144  bool success{false};
145  bool request_more{false};
146  };
147 
168  ProcessingResult ProcessNextHeaders(const std::vector<CBlockHeader>&
169  received_headers, bool full_headers_message);
170 
177 
178 protected:
183  const unsigned m_commit_offset;
184 
185 private:
189  void Finalize();
190 
198  bool ValidateAndStoreHeadersCommitments(const std::vector<CBlockHeader>& headers);
199 
201  bool ValidateAndProcessSingleHeader(const CBlockHeader& current);
202 
206 
208  std::vector<CBlockHeader> PopHeadersReadyForAcceptance();
209 
210 private:
212  const NodeId m_id;
213 
216 
218  const CBlockIndex* m_chain_start{nullptr};
219 
222 
225 
228 
231 
237  uint64_t m_max_commitments{0};
238 
241 
243  int64_t m_current_height{0};
244 
248  std::deque<CompressedHeader> m_redownloaded_headers;
249 
252 
258 
264 
267 
273 
276 };
277 
278 #endif // BITCOIN_HEADERSSYNC_H
int ret
Nodes collect new transactions into a block, hash them into a hash tree, and scan through nonce value...
Definition: block.h:22
uint32_t nNonce
Definition: block.h:30
uint32_t nBits
Definition: block.h:29
uint32_t nTime
Definition: block.h:28
int32_t nVersion
Definition: block.h:25
uint256 hashMerkleRoot
Definition: block.h:27
The block chain is a tree shaped structure starting with the genesis block at the root,...
Definition: chain.h:150
HeadersSyncState:
Definition: headerssync.h:101
arith_uint256 GetPresyncWork() const
Return the amount of work in the chain received during the PRESYNC phase.
Definition: headerssync.h:128
const SaltedTxidHasher m_hasher
m_hasher is a salted hasher for making our 1-bit commitments to headers we've seen.
Definition: headerssync.h:227
uint64_t m_max_commitments
m_max_commitments is a bound we calculate on how long an honest peer's chain could be,...
Definition: headerssync.h:237
HeadersSyncState(NodeId id, const Consensus::Params &consensus_params, const CBlockIndex *chain_start, const arith_uint256 &minimum_required_work)
Construct a HeadersSyncState object representing a headers sync via this download-twice mechanism).
Definition: headerssync.cpp:26
arith_uint256 m_redownload_chain_work
The accumulated work on the redownloaded chain.
Definition: headerssync.h:266
@ FINAL
We're done syncing with this peer and can discard any remaining state.
@ PRESYNC
PRESYNC means the peer has not yet demonstrated their chain has sufficient work and we're only buildi...
@ REDOWNLOAD
REDOWNLOAD means the peer has given us a high-enough-work chain, and now we're redownloading the head...
CBlockHeader m_last_header_received
Store the latest header received while in PRESYNC (initialized to m_chain_start)
Definition: headerssync.h:240
arith_uint256 m_current_chain_work
Work that we've seen so far on the peer's chain.
Definition: headerssync.h:224
int64_t m_current_height
Height of m_last_header_received.
Definition: headerssync.h:243
const unsigned m_commit_offset
The (secret) offset on the heights for which to create commitments.
Definition: headerssync.h:183
uint32_t GetPresyncTime() const
Return the block timestamp of the last header received during the PRESYNC phase.
Definition: headerssync.h:125
const arith_uint256 m_minimum_required_work
Minimum work that we're looking for on this chain.
Definition: headerssync.h:221
std::vector< CBlockHeader > PopHeadersReadyForAcceptance()
Return a set of headers that satisfy our proof-of-work threshold.
bool ValidateAndStoreHeadersCommitments(const std::vector< CBlockHeader > &headers)
Only called in PRESYNC.
const Consensus::Params & m_consensus_params
We use the consensus params in our anti-DoS calculations.
Definition: headerssync.h:215
bool ValidateAndProcessSingleHeader(const CBlockHeader &current)
In PRESYNC, process and update state for a single header.
State m_download_state
Current state of our headers sync.
Definition: headerssync.h:275
bool ValidateAndStoreRedownloadedHeader(const CBlockHeader &header)
In REDOWNLOAD, check a header's commitment (if applicable) and add to buffer for later processing.
bitdeque m_header_commitments
A queue of commitment bits, created during the 1st phase, and verified during the 2nd.
Definition: headerssync.h:230
const NodeId m_id
NodeId of the peer (used for log messages)
Definition: headerssync.h:212
int64_t m_redownload_buffer_last_height
Height of last header in m_redownloaded_headers.
Definition: headerssync.h:251
std::deque< CompressedHeader > m_redownloaded_headers
During phase 2 (REDOWNLOAD), we buffer redownloaded headers in memory until enough commitments have b...
Definition: headerssync.h:248
ProcessingResult ProcessNextHeaders(const std::vector< CBlockHeader > &received_headers, bool full_headers_message)
Process a batch of headers, once a sync via this mechanism has started.
Definition: headerssync.cpp:69
State GetState() const
Return the current state of our download.
Definition: headerssync.h:119
bool m_process_all_remaining_headers
Set this to true once we encounter the target blockheader during phase 2 (REDOWNLOAD).
Definition: headerssync.h:272
void Finalize()
Clear out all download state that might be in progress (freeing any used memory), and mark this objec...
Definition: headerssync.cpp:52
uint256 m_redownload_buffer_last_hash
Hash of last header in m_redownloaded_headers (initialized to m_chain_start).
Definition: headerssync.h:257
uint256 m_redownload_buffer_first_prev_hash
The hashPrevBlock entry for the first header in m_redownloaded_headers We need this to reconstruct th...
Definition: headerssync.h:263
const CBlockIndex * m_chain_start
Store the last block in our block index that the peer's chain builds from.
Definition: headerssync.h:218
int64_t GetPresyncHeight() const
Return the height reached during the PRESYNC phase.
Definition: headerssync.h:122
CBlockLocator NextHeadersRequestLocator() const
Issue the next GETHEADERS message to our peer.
256-bit unsigned big integer.
constexpr void SetNull()
Definition: uint256.h:49
Class that mimics std::deque<bool>, but with std::vector<bool>'s bit packing.
Definition: bitdeque.h:23
256-bit opaque blob.
Definition: uint256.h:106
int64_t NodeId
Definition: net.h:102
Describes a place in the block chain to another node such that if the other node doesn't have the sam...
Definition: block.h:120
uint32_t nBits
Definition: headerssync.h:26
CBlockHeader GetFullHeader(const uint256 &hash_prev_block)
Definition: headerssync.h:43
uint32_t nTime
Definition: headerssync.h:25
uint32_t nNonce
Definition: headerssync.h:27
uint256 hashMerkleRoot
Definition: headerssync.h:24
int32_t nVersion
Definition: headerssync.h:23
CompressedHeader(const CBlockHeader &header)
Definition: headerssync.h:34
Parameters that influence chain consensus.
Definition: params.h:74
Result data structure for ProcessNextHeaders.
Definition: headerssync.h:142
std::vector< CBlockHeader > pow_validated_headers
Definition: headerssync.h:143