blocktools.py raw
1 #!/usr/bin/env python3
2 # Copyright (c) 2015-present The Limenka developers
3 # Distributed under the MIT software license, see the accompanying
4 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
5 """Utilities for manipulating blocks and transactions."""
6
7 import struct
8 import time
9 import unittest
10
11 from .address import (
12 address_to_scriptpubkey,
13 key_to_p2sh_p2wpkh,
14 key_to_p2wpkh,
15 script_to_p2sh_p2wsh,
16 script_to_p2wsh,
17 )
18 from .messages import (
19 CBlock,
20 COIN,
21 COutPoint,
22 CTransaction,
23 CTxIn,
24 CTxInWitness,
25 CTxOut,
26 SEQUENCE_FINAL,
27 hash256,
28 ser_uint256,
29 tx_from_hex,
30 uint256_from_compact,
31 uint256_from_str,
32 WITNESS_SCALE_FACTOR,
33 )
34 from .script import (
35 CScript,
36 CScriptNum,
37 CScriptOp,
38 OP_0,
39 OP_RETURN,
40 OP_TRUE,
41 )
42 from .script_util import (
43 key_to_p2pk_script,
44 key_to_p2wpkh_script,
45 keys_to_multisig_script,
46 script_to_p2wsh_script,
47 )
48 from .util import assert_equal
49
50 MAX_BLOCK_SIGOPS = 20000
51 MAX_BLOCK_SIGOPS_WEIGHT = MAX_BLOCK_SIGOPS * WITNESS_SCALE_FACTOR
52 MAX_STANDARD_TX_WEIGHT = 400000
53
54 # Genesis block time (regtest)
55 TIME_GENESIS_BLOCK = 1296688602
56
57 MAX_FUTURE_BLOCK_TIME = 2 * 60 * 60
58
59 # Coinbase transaction outputs can only be spent after this number of new blocks (network rule)
60 COINBASE_MATURITY = 100
61
62 # From BIP141
63 WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed"
64
65 NORMAL_GBT_REQUEST_PARAMS = {"rules": ["segwit"]}
66 VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4
67 MIN_BLOCKS_TO_KEEP = 288
68
69 REGTEST_RETARGET_PERIOD = 150
70
71 REGTEST_N_BITS = 0x207fffff # difficulty retargeting is disabled in REGTEST chainparams"
72 REGTEST_TARGET = 0x7fffff0000000000000000000000000000000000000000000000000000000000
73 assert_equal(uint256_from_compact(REGTEST_N_BITS), REGTEST_TARGET)
74
75 DIFF_1_N_BITS = 0x1d00ffff
76 DIFF_1_TARGET = 0x00000000ffff0000000000000000000000000000000000000000000000000000
77 assert_equal(uint256_from_compact(DIFF_1_N_BITS), DIFF_1_TARGET)
78
79 DIFF_4_N_BITS = 0x1c3fffc0
80 DIFF_4_TARGET = int(DIFF_1_TARGET / 4)
81 assert_equal(uint256_from_compact(DIFF_4_N_BITS), DIFF_4_TARGET)
82
83 def nbits_str(nbits):
84 return f"{nbits:08x}"
85
86 def target_str(target):
87 return f"{target:064x}"
88
89 def create_block(hashprev=None, coinbase=None, ntime=None, *, version=None, tmpl=None, txlist=None):
90 """Create a block (with regtest difficulty)."""
91 block = CBlock()
92 if tmpl is None:
93 tmpl = {}
94 block.nVersion = version or tmpl.get('version') or VERSIONBITS_LAST_OLD_BLOCK_VERSION
95 block.nTime = ntime or tmpl.get('curtime') or int(time.time() + 600)
96 block.hashPrevBlock = hashprev or int(tmpl['previousblockhash'], 0x10)
97 if tmpl and tmpl.get('bits') is not None:
98 block.nBits = struct.unpack('>I', bytes.fromhex(tmpl['bits']))[0]
99 else:
100 block.nBits = REGTEST_N_BITS
101 if coinbase is None:
102 coinbase = create_coinbase(height=tmpl['height'])
103 block.vtx.append(coinbase)
104 if txlist:
105 for tx in txlist:
106 if not hasattr(tx, 'calc_sha256'):
107 tx = tx_from_hex(tx)
108 block.vtx.append(tx)
109 block.hashMerkleRoot = block.calc_merkle_root()
110 block.calc_sha256()
111 return block
112
113 def get_witness_script(witness_root, witness_nonce):
114 witness_commitment = uint256_from_str(hash256(ser_uint256(witness_root) + ser_uint256(witness_nonce)))
115 output_data = WITNESS_COMMITMENT_HEADER + ser_uint256(witness_commitment)
116 return CScript([OP_RETURN, output_data])
117
118 def add_witness_commitment(block, nonce=0):
119 """Add a witness commitment to the block's coinbase transaction.
120
121 According to BIP141, blocks with witness rules active must commit to the
122 hash of all in-block transactions including witness."""
123 # First calculate the merkle root of the block's
124 # transactions, with witnesses.
125 witness_nonce = nonce
126 witness_root = block.calc_witness_merkle_root()
127 # witness_nonce should go to coinbase witness.
128 block.vtx[0].wit.vtxinwit = [CTxInWitness()]
129 block.vtx[0].wit.vtxinwit[0].scriptWitness.stack = [ser_uint256(witness_nonce)]
130
131 # witness commitment is the last OP_RETURN output in coinbase
132 block.vtx[0].vout.append(CTxOut(0, get_witness_script(witness_root, witness_nonce)))
133 block.vtx[0].rehash()
134 block.hashMerkleRoot = block.calc_merkle_root()
135 block.rehash()
136
137
138 def script_BIP34_coinbase_height(height):
139 if height <= 16:
140 res = CScriptOp.encode_op_n(height)
141 # Append dummy to increase scriptSig size to 2 (see bad-cb-length consensus rule)
142 return CScript([res, OP_0])
143 return CScript([CScriptNum(height)])
144
145
146 def create_coinbase(height, pubkey=None, *, script_pubkey=None, extra_output_script=None, fees=0, nValue=50, halving_period=REGTEST_RETARGET_PERIOD):
147 """Create a coinbase transaction.
148
149 If pubkey is passed in, the coinbase output will be a P2PK output;
150 otherwise an anyone-can-spend output.
151
152 If extra_output_script is given, make a 0-value output to that
153 script. This is useful to pad block weight/sigops as needed. """
154 coinbase = CTransaction()
155 coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff), script_BIP34_coinbase_height(height), SEQUENCE_FINAL))
156 coinbaseoutput = CTxOut()
157 coinbaseoutput.nValue = nValue * COIN
158 if nValue == 50:
159 halvings = int(height / halving_period)
160 coinbaseoutput.nValue >>= halvings
161 coinbaseoutput.nValue += fees
162 if pubkey is not None:
163 coinbaseoutput.scriptPubKey = key_to_p2pk_script(pubkey)
164 elif script_pubkey is not None:
165 coinbaseoutput.scriptPubKey = script_pubkey
166 else:
167 coinbaseoutput.scriptPubKey = CScript([OP_TRUE])
168 coinbase.vout = [coinbaseoutput]
169 if extra_output_script is not None:
170 coinbaseoutput2 = CTxOut()
171 coinbaseoutput2.nValue = 0
172 coinbaseoutput2.scriptPubKey = extra_output_script
173 coinbase.vout.append(coinbaseoutput2)
174 coinbase.calc_sha256()
175 return coinbase
176
177 def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, output_script=None):
178 """Return one-input, one-output transaction object
179 spending the prevtx's n-th output with the given amount.
180
181 Can optionally pass scriptPubKey and scriptSig, default is anyone-can-spend output.
182 """
183 if output_script is None:
184 output_script = CScript()
185 tx = CTransaction()
186 assert n < len(prevtx.vout)
187 tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), script_sig, SEQUENCE_FINAL))
188 tx.vout.append(CTxOut(amount, output_script))
189 tx.calc_sha256()
190 return tx
191
192 def get_legacy_sigopcount_block(block, accurate=True):
193 count = 0
194 for tx in block.vtx:
195 count += get_legacy_sigopcount_tx(tx, accurate)
196 return count
197
198 def get_legacy_sigopcount_tx(tx, accurate=True):
199 count = 0
200 for i in tx.vout:
201 count += i.scriptPubKey.GetSigOpCount(accurate)
202 for j in tx.vin:
203 # scriptSig might be of type bytes, so convert to CScript for the moment
204 count += CScript(j.scriptSig).GetSigOpCount(accurate)
205 return count
206
207 def witness_script(use_p2wsh, pubkey):
208 """Create a scriptPubKey for a pay-to-witness TxOut.
209
210 This is either a P2WPKH output for the given pubkey, or a P2WSH output of a
211 1-of-1 multisig for the given pubkey. Returns the hex encoding of the
212 scriptPubKey."""
213 if not use_p2wsh:
214 # P2WPKH instead
215 pkscript = key_to_p2wpkh_script(pubkey)
216 else:
217 # 1-of-1 multisig
218 witness_script = keys_to_multisig_script([pubkey])
219 pkscript = script_to_p2wsh_script(witness_script)
220 return pkscript.hex()
221
222 def create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount):
223 """Return a transaction (in hex) that spends the given utxo to a segwit output.
224
225 Optionally wrap the segwit output using P2SH."""
226 if use_p2wsh:
227 program = keys_to_multisig_script([pubkey])
228 addr = script_to_p2sh_p2wsh(program) if encode_p2sh else script_to_p2wsh(program)
229 else:
230 addr = key_to_p2sh_p2wpkh(pubkey) if encode_p2sh else key_to_p2wpkh(pubkey)
231 if not encode_p2sh:
232 assert_equal(address_to_scriptpubkey(addr).hex(), witness_script(use_p2wsh, pubkey))
233 return node.createrawtransaction([utxo], {addr: amount})
234
235 def send_to_witness(use_p2wsh, node, utxo, pubkey, encode_p2sh, amount, sign=True, insert_redeem_script=""):
236 """Create a transaction spending a given utxo to a segwit output.
237
238 The output corresponds to the given pubkey: use_p2wsh determines whether to
239 use P2WPKH or P2WSH; encode_p2sh determines whether to wrap in P2SH.
240 sign=True will have the given node sign the transaction.
241 insert_redeem_script will be added to the scriptSig, if given."""
242 tx_to_witness = create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount)
243 if (sign):
244 signed = node.signrawtransactionwithwallet(tx_to_witness)
245 assert "errors" not in signed or len(["errors"]) == 0
246 return node.sendrawtransaction(signed["hex"])
247 else:
248 if (insert_redeem_script):
249 tx = tx_from_hex(tx_to_witness)
250 tx.vin[0].scriptSig += CScript([bytes.fromhex(insert_redeem_script)])
251 tx_to_witness = tx.serialize().hex()
252
253 return node.sendrawtransaction(tx_to_witness)
254
255 class TestFrameworkBlockTools(unittest.TestCase):
256 def test_create_coinbase(self):
257 height = 20
258 coinbase_tx = create_coinbase(height=height)
259 assert_equal(CScriptNum.decode(coinbase_tx.vin[0].scriptSig), height)
260