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#!/usr/bin/env python3
# Copyright (c) 2023 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test sigop limit mempool policy (`-bytespersigop` parameter)"""
from math import ceil
from test_framework.messages import (
COutPoint,
CTransaction,
CTxIn,
CTxInWitness,
CTxOut,
WITNESS_SCALE_FACTOR,
)
from test_framework.script import (
CScript,
OP_CHECKMULTISIG,
OP_CHECKSIG,
OP_ENDIF,
OP_FALSE,
OP_IF,
OP_RETURN,
OP_TRUE,
)
from test_framework.script_util import (
script_to_p2wsh_script,
)
from test_framework.test_framework import BitcoinTestFramework
from test_framework.util import (
assert_equal,
assert_greater_than_or_equal,
)
from test_framework.wallet import MiniWallet
DEFAULT_BYTES_PER_SIGOP = 20 # default setting
class BytesPerSigOpTest(BitcoinTestFramework):
def set_test_params(self):
self.num_nodes = 1
# allow large datacarrier output to pad transactions
self.extra_args = [['-datacarriersize=100000']]
def create_p2wsh_spending_tx(self, witness_script, output_script):
"""Create a 1-input-1-output P2WSH spending transaction with only the
witness script in the witness stack and the given output script."""
# create P2WSH address and fund it via MiniWallet first
txid, vout = self.wallet.send_to(
from_node=self.nodes[0],
scriptPubKey=script_to_p2wsh_script(witness_script),
amount=1000000,
)
# create spending transaction
tx = CTransaction()
tx.vin = [CTxIn(COutPoint(int(txid, 16), vout))]
tx.wit.vtxinwit = [CTxInWitness()]
tx.wit.vtxinwit[0].scriptWitness.stack = [bytes(witness_script)]
tx.vout = [CTxOut(500000, output_script)]
return tx
def test_sigops_limit(self, bytes_per_sigop, num_sigops):
sigop_equivalent_vsize = ceil(num_sigops * bytes_per_sigop / WITNESS_SCALE_FACTOR)
self.log.info(f"- {num_sigops} sigops (equivalent size of {sigop_equivalent_vsize} vbytes)")
# create a template tx with the specified sigop cost in the witness script
# (note that the sigops count even though being in a branch that's not executed)
num_multisigops = num_sigops // 20
num_singlesigops = num_sigops % 20
witness_script = CScript(
[OP_FALSE, OP_IF] +
[OP_CHECKMULTISIG]*num_multisigops +
[OP_CHECKSIG]*num_singlesigops +
[OP_ENDIF, OP_TRUE]
)
# use a 256-byte data-push as lower bound in the output script, in order
# to avoid having to compensate for tx size changes caused by varying
# length serialization sizes (both for scriptPubKey and data-push lengths)
tx = self.create_p2wsh_spending_tx(witness_script, CScript([OP_RETURN, b'X'*256]))
# bump the tx to reach the sigop-limit equivalent size by padding the datacarrier output
assert_greater_than_or_equal(sigop_equivalent_vsize, tx.get_vsize())
vsize_to_pad = sigop_equivalent_vsize - tx.get_vsize()
tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad)])
assert_equal(sigop_equivalent_vsize, tx.get_vsize())
res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
assert_equal(res['allowed'], True)
assert_equal(res['vsize'], sigop_equivalent_vsize)
# increase the tx's vsize to be right above the sigop-limit equivalent size
# => tx's vsize in mempool should also grow accordingly
tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad+1)])
res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
assert_equal(res['allowed'], True)
assert_equal(res['vsize'], sigop_equivalent_vsize+1)
# decrease the tx's vsize to be right below the sigop-limit equivalent size
# => tx's vsize in mempool should stick at the sigop-limit equivalent
# bytes level, as it is higher than the tx's serialized vsize
# (the maximum of both is taken)
tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad-1)])
res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
assert_equal(res['allowed'], True)
assert_equal(res['vsize'], sigop_equivalent_vsize)
def run_test(self):
self.wallet = MiniWallet(self.nodes[0])
for bytes_per_sigop in (DEFAULT_BYTES_PER_SIGOP, 43, 81, 165, 327, 649, 1072):
if bytes_per_sigop == DEFAULT_BYTES_PER_SIGOP:
self.log.info(f"Test default sigops limit setting ({bytes_per_sigop} bytes per sigop)...")
else:
bytespersigop_parameter = f"-bytespersigop={bytes_per_sigop}"
self.log.info(f"Test sigops limit setting {bytespersigop_parameter}...")
self.restart_node(0, extra_args=[bytespersigop_parameter] + self.extra_args[0])
for num_sigops in (69, 101, 142, 183, 222):
self.test_sigops_limit(bytes_per_sigop, num_sigops)
if __name__ == '__main__':
BytesPerSigOpTest().main()
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