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.

58,914 bytes · SHA-256 976c1f77654f2a17… · View upstream ↗

1#!/usr/bin/env python3
2# Copyright (c) 2010 ArtForz -- public domain half-a-node
3# Copyright (c) 2012 Jeff Garzik
4# Copyright (c) 2010-present The Bitcoin Core developers
5# Distributed under the MIT software license, see the accompanying
6# file COPYING or http://www.opensource.org/licenses/mit-license.php.
7"""Bitcoin test framework primitive and message structures
8
9CBlock, CTransaction, CBlockHeader, CTxIn, CTxOut, etc....:
10    data structures that should map to corresponding structures in
11    bitcoin/primitives
12
13msg_block, msg_tx, msg_headers, etc.:
14    data structures that represent network messages
15
16ser_*, deser_*: functions that handle serialization/deserialization.
17
18Classes use __slots__ to ensure extraneous attributes aren't accidentally added
19by tests, compromising their intended effect.
20"""
21from base64 import b32decode, b32encode
22import copy
23import hashlib
24from io import BytesIO
25import math
26import random
27import socket
28import time
29import unittest
30
31from test_framework.crypto.siphash import siphash256
32from test_framework.util import (
33    assert_equal,
34    assert_not_equal,
35)
36
37MAX_LOCATOR_SZ = 101
38MAX_BLOCK_WEIGHT = 4000000
39MAX_BLOCK_SIGOPS_COST = 80000
40DEFAULT_BLOCK_RESERVED_WEIGHT = 8000
41MINIMUM_BLOCK_RESERVED_WEIGHT = 2000
42MAX_BLOOM_FILTER_SIZE = 36000
43MAX_BLOOM_HASH_FUNCS = 50
44
45COIN = 100000000  # 1 btc in satoshis
46MAX_MONEY = 21000000 * COIN
47
48MAX_BIP125_RBF_SEQUENCE = 0xfffffffd  # Sequence number that is rbf-opt-in (BIP 125) and csv-opt-out (BIP 68)
49MAX_SEQUENCE_NONFINAL = 0xfffffffe  # Sequence number that is csv-opt-out (BIP 68)
50SEQUENCE_FINAL = 0xffffffff  # Sequence number that disables nLockTime if set for every input of a tx
51
52MAX_PROTOCOL_MESSAGE_LENGTH = 4000000  # Maximum length of incoming protocol messages
53MAX_HEADERS_RESULTS = 2000  # Number of headers sent in one getheaders result
54MAX_INV_SIZE = 50000  # Maximum number of entries in an 'inv' protocol message
55
56NODE_NONE = 0
57NODE_NETWORK = (1 << 0)
58NODE_BLOOM = (1 << 2)
59NODE_WITNESS = (1 << 3)
60NODE_COMPACT_FILTERS = (1 << 6)
61NODE_NETWORK_LIMITED = (1 << 10)
62NODE_P2P_V2 = (1 << 11)
63
64MSG_TX = 1
65MSG_BLOCK = 2
66MSG_FILTERED_BLOCK = 3
67MSG_CMPCT_BLOCK = 4
68MSG_WTX = 5
69MSG_WITNESS_FLAG = 1 << 30
70MSG_TYPE_MASK = 0xffffffff >> 2
71MSG_WITNESS_TX = MSG_TX | MSG_WITNESS_FLAG
72
73FILTER_TYPE_BASIC = 0
74
75WITNESS_SCALE_FACTOR = 4
76
77DEFAULT_ANCESTOR_LIMIT = 25    # default max number of in-mempool ancestors
78DEFAULT_DESCENDANT_LIMIT = 25  # default max number of in-mempool descendants
79DEFAULT_CLUSTER_LIMIT = 64     # default max number of transactions in a cluster
80
81
82# Default setting for -datacarriersize.
83MAX_OP_RETURN_RELAY = 100_000
84
85
86DEFAULT_MEMPOOL_EXPIRY_HOURS = 336  # hours
87
88TX_MIN_STANDARD_VERSION = 1
89TX_MAX_STANDARD_VERSION = 3
90
91MAGIC_BYTES = {
92    "mainnet": b"\xf9\xbe\xb4\xd9",
93    "testnet4": b"\x1c\x16\x3f\x28",
94    "regtest": b"\xfa\xbf\xb5\xda",
95    "signet": b"\x0a\x03\xcf\x40",
96}
97
98def sha256(s):
99    return hashlib.sha256(s).digest()
100
101
102def sha3(s):
103    return hashlib.sha3_256(s).digest()
104
105
106def hash256(s):
107    return sha256(sha256(s))
108
109
110def ser_compact_size(l):
111    r = b""
112    if l < 253:
113        r = l.to_bytes(1, "little")
114    elif l < 0x10000:
115        r = (253).to_bytes(1, "little") + l.to_bytes(2, "little")
116    elif l < 0x100000000:
117        r = (254).to_bytes(1, "little") + l.to_bytes(4, "little")
118    else:
119        r = (255).to_bytes(1, "little") + l.to_bytes(8, "little")
120    return r
121
122
123def deser_compact_size(f):
124    nit = int.from_bytes(f.read(1), "little")
125    if nit == 253:
126        nit = int.from_bytes(f.read(2), "little")
127    elif nit == 254:
128        nit = int.from_bytes(f.read(4), "little")
129    elif nit == 255:
130        nit = int.from_bytes(f.read(8), "little")
131    return nit
132
133
134def ser_varint(l):
135    r = b""
136    while True:
137        r = bytes([(l & 0x7f) | (0x80 if len(r) > 0 else 0x00)]) + r
138        if l <= 0x7f:
139            return r
140        l = (l >> 7) - 1
141
142
143def deser_varint(f):
144    n = 0
145    while True:
146        dat = f.read(1)[0]
147        n = (n << 7) | (dat & 0x7f)
148        if (dat & 0x80) > 0:
149            n += 1
150        else:
151            return n
152
153
154def deser_string(f):
155    nit = deser_compact_size(f)
156    return f.read(nit)
157
158
159def ser_string(s):
160    return ser_compact_size(len(s)) + s
161
162
163def deser_uint256(f):
164    return int.from_bytes(f.read(32), 'little')
165
166
167def ser_uint256(u):
168    return u.to_bytes(32, 'little')
169
170
171def uint256_from_str(s):
172    return int.from_bytes(s[:32], 'little')
173
174
175def uint256_from_compact(c):
176    nbytes = (c >> 24) & 0xFF
177    v = (c & 0xFFFFFF) << (8 * (nbytes - 3))
178    return v
179
180
181# deser_function_name: Allow for an alternate deserialization function on the
182# entries in the vector.
183def deser_vector(f, c, deser_function_name=None):
184    nit = deser_compact_size(f)
185    r = []
186    for _ in range(nit):
187        t = c()
188        if deser_function_name:
189            getattr(t, deser_function_name)(f)
190        else:
191            t.deserialize(f)
192        r.append(t)
193    return r
194
195
196# ser_function_name: Allow for an alternate serialization function on the
197# entries in the vector (we use this for serializing the vector of transactions
198# for a witness block).
199def ser_vector(l, ser_function_name=None):
200    r = ser_compact_size(len(l))
201    for i in l:
202        if ser_function_name:
203            r += getattr(i, ser_function_name)()
204        else:
205            r += i.serialize()
206    return r
207
208
209def deser_uint256_vector(f):
210    nit = deser_compact_size(f)
211    r = []
212    for _ in range(nit):
213        t = deser_uint256(f)
214        r.append(t)
215    return r
216
217
218def ser_uint256_vector(l):
219    r = ser_compact_size(len(l))
220    for i in l:
221        r += ser_uint256(i)
222    return r
223
224
225def deser_string_vector(f):
226    nit = deser_compact_size(f)
227    r = []
228    for _ in range(nit):
229        t = deser_string(f)
230        r.append(t)
231    return r
232
233
234def ser_string_vector(l):
235    r = ser_compact_size(len(l))
236    for sv in l:
237        r += ser_string(sv)
238    return r
239
240
241def deser_block_spent_outputs(f):
242    nit = deser_compact_size(f)
243    return [deser_vector(f, CTxOut) for _ in range(nit)]
244
245
246def from_hex(obj, hex_string):
247    """Deserialize from a hex string representation (e.g. from RPC)
248
249    Note that there is no complementary helper like e.g. `to_hex` for the
250    inverse operation. To serialize a message object to a hex string, simply

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.