READ THE CODE

Inside Bitcoin

The code behind the network, with room to understand it.

Stable release v32.1bitcoin/bitcoin · f0de87f04062 ↗3,020 source files · 47.5 MB stored on the server440 file guides

Release published 2026-10-28 · Snapshot fetched 2026-11-01. Latest stable release at fetch time; development branches and Git history are excluded. Only the selected code window and visible folders load here.

4,892 bytes · SHA-256 300cc7054746ecf2… · View upstream ↗

1// Copyright (c) 2022-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or https://opensource.org/license/mit.
4
5#include <arith_uint256.h>
6#include <chain.h>
7#include <chainparams.h>
8#include <headerssync.h>
9#include <test/fuzz/fuzz.h>
10#include <test/fuzz/util.h>
11#include <test/util/setup_common.h>
12#include <test/util/time.h>
13#include <uint256.h>
14#include <util/chaintype.h>
15#include <util/time.h>
16#include <validation.h>
17
18#include <iterator>
19#include <vector>
20
21static void initialize_headers_sync_state_fuzz()
22{
23    static const auto testing_setup = MakeNoLogFileContext<>(
24        /*chain_type=*/ChainType::MAIN);
25}
26
27void MakeHeadersContinuous(
28    const CBlockHeader& genesis_header,
29    const std::vector<CBlockHeader>& all_headers,
30    std::vector<CBlockHeader>& new_headers)
31{
32    Assume(!new_headers.empty());
33
34    const CBlockHeader* prev_header{
35        all_headers.empty() ? &genesis_header : &all_headers.back()};
36
37    for (auto& header : new_headers) {
38        header.hashPrevBlock = prev_header->GetHash();
39
40        prev_header = &header;
41    }
42}
43
44class FuzzedHeadersSyncState : public HeadersSyncState
45{
46public:
47    FuzzedHeadersSyncState(const HeadersSyncParams& sync_params, const size_t commit_offset,
48                           const CBlockIndex& chain_start, const arith_uint256& minimum_required_work)
49        : HeadersSyncState(/*id=*/0, Params().GetConsensus(), sync_params, chain_start, minimum_required_work)
50    {
51        const_cast<size_t&>(m_commit_offset) = commit_offset;
52    }
53};
54
55FUZZ_TARGET(headers_sync_state, .init = initialize_headers_sync_state_fuzz)
56{
57    SeedRandomStateForTest(SeedRand::ZEROS);
58    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
59
60    CBlockHeader genesis_header{Params().GenesisBlock()};
61    CBlockIndex start_index(genesis_header);
62
63    FakeNodeClock clock{ConsumeTime(fuzzed_data_provider, /*min=*/start_index.GetMedianTimePast())};
64
65    const uint256 genesis_hash = genesis_header.GetHash();
66    start_index.phashBlock = &genesis_hash;
67
68    const HeadersSyncParams params{
69        .commitment_period = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(1, Params().HeadersSync().commitment_period * 2),
70        .redownload_buffer_size = fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, Params().HeadersSync().redownload_buffer_size * 2),
71    };
72    arith_uint256 min_work{UintToArith256(ConsumeUInt256(fuzzed_data_provider))};
73    FuzzedHeadersSyncState headers_sync(
74        params,
75        /*commit_offset=*/fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, params.commitment_period - 1),
76        /*chain_start=*/start_index,
77        /*minimum_required_work=*/min_work);
78
79    // Store headers for potential redownload phase.
80    std::vector<CBlockHeader> all_headers;
81    std::vector<CBlockHeader>::const_iterator redownloaded_it;
82    bool presync{true};
83    bool requested_more{true};
84
85    while (requested_more) {
86        std::vector<CBlockHeader> headers;
87
88        // Consume headers from fuzzer or maybe replay headers if we got to the
89        // redownload phase.
90        if (presync || fuzzed_data_provider.ConsumeBool()) {
91            auto deser_headers = ConsumeDeserializable<std::vector<CBlockHeader>>(fuzzed_data_provider);
92            if (!deser_headers || deser_headers->empty()) return;
93
94            if (fuzzed_data_provider.ConsumeBool()) {
95                MakeHeadersContinuous(genesis_header, all_headers, *deser_headers);
96            }
97
98            headers.swap(*deser_headers);
99        } else if (auto num_headers_left{std::distance(redownloaded_it, all_headers.cend())}; num_headers_left > 0) {
100            // Consume some headers from the redownload buffer (At least one
101            // header is consumed).
102            auto begin_it{redownloaded_it};
103            std::advance(redownloaded_it, fuzzed_data_provider.ConsumeIntegralInRange<int>(1, num_headers_left));
104            headers.insert(headers.cend(), begin_it, redownloaded_it);
105        }
106
107        if (headers.empty()) return;
108        auto result = headers_sync.ProcessNextHeaders(headers, fuzzed_data_provider.ConsumeBool());
109        requested_more = result.request_more;
110
111        if (result.request_more) {
112            if (presync) {
113                all_headers.insert(all_headers.cend(), headers.cbegin(), headers.cend());
114
115                if (headers_sync.GetState() == HeadersSyncState::State::REDOWNLOAD) {
116                    presync = false;
117                    redownloaded_it = all_headers.cbegin();
118
119                    // If we get to redownloading, the presynced headers need
120                    // to have the min amount of work on them.
121                    assert(CalculateClaimedHeadersWork(all_headers) >= min_work);
122                }
123            }
124
125            (void)headers_sync.NextHeadersRequestLocator();
126        }
127    }
128}
129

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

src/clientversion.cpp

src/common/signmessage.cpp

src/compat/assumptions.h

src/compat/byteswap.h

src/deploymentinfo.cpp

src/deploymentinfo.h

src/deploymentstatus.cpp

src/deploymentstatus.h

src/dummywallet.cpp

src/external_signer.h

src/init/bitcoin-gui.cpp

src/init/bitcoin-node.cpp

src/init/bitcoin-qt.cpp

src/init/bitcoin-wallet.cpp

src/init/bitcoind.cpp

src/init/common.h

src/interfaces/init.h

src/interfaces/ipc.h

src/key_io.h

src/logging/categories.h

src/logging/timer.h

src/mapport.h

src/musig.h

src/net_permissions.h

src/netgroup.h

src/netmessagemaker.h

src/node/chainstatemanager_args.cpp

src/node/connection_types.h

src/node/context.h

src/node/interface_ui.h

src/node/mempool_args.cpp

src/node/mining_args.cpp

src/node/minisketchwrapper.cpp

src/node/txreconciliation.h

src/policy/fees/estimator_args.cpp

src/policy/fees/estimator_args.h

src/policy/fees/estimator_man.cpp

src/policy/fees/estimator_man.h

src/policy/packages.h

src/policy/rbf.h

src/policy/truc_policy.h

src/pow.h

src/primitives/block.cpp

src/randomenv.h

src/rest.h

src/script/keyorigin.h

src/script/parsing.cpp

src/script/parsing.h

src/script/script_error.h

src/script/sigcache.cpp

src/script/sigcache.h

src/script/solver.h

src/script/verify_flags.h

src/semaphore_grant.h

src/signet.h

src/span.h

src/support/allocators/secure.h

src/support/allocators/zeroafterfree.h

src/util/tokenpipe.cpp

src/util/translation.h

src/util/vector.h

src/versionbits.h

src/versionbits_impl.h

src/wallet/external_signer_scriptpubkeyman.h

src/wallet/fees.h

src/wallet/load.h

src/wallet/receive.h

src/wallet/rpc/wallet.h

src/wallet/types.h

src/walletinitinterface.h

src/zmq/zmqabstractnotifier.cpp

Independent explanations by MyBitcoinExplorer. Not affiliated with or endorsed by Bitcoin Core. Guides are educational and do not replace the source or its tests.

Bitcoin Core source © its contributors, distributed under the MIT license. Original notices and bundled third-party licenses are retained in the source tree.