#!/usr/bin/env python3 # Copyright (c) 2015-present The Bitcoin Core developers # Distributed under the MIT software license, see the accompanying # file COPYING or http://www.opensource.org/licenses/mit-license.php. """Utilities for manipulating blocks and transactions.""" import struct import time import unittest from .address import ( address_to_scriptpubkey, key_to_p2sh_p2wpkh, key_to_p2wpkh, script_to_p2sh_p2wsh, script_to_p2wsh, ) from .messages import ( CBlock, COIN, COutPoint, CTransaction, CTxIn, CTxInWitness, CTxOut, SEQUENCE_FINAL, hash256, ser_uint256, tx_from_hex, uint256_from_str, WITNESS_SCALE_FACTOR, ) from .script import ( CScript, CScriptNum, CScriptOp, OP_1, OP_RETURN, OP_TRUE, ) from .script_util import ( key_to_p2pk_script, key_to_p2wpkh_script, keys_to_multisig_script, script_to_p2wsh_script, ) from .util import assert_equal MAX_BLOCK_SIGOPS = 20000 MAX_BLOCK_SIGOPS_WEIGHT = MAX_BLOCK_SIGOPS * WITNESS_SCALE_FACTOR MAX_STANDARD_TX_WEIGHT = 400000 # Genesis block time (regtest) TIME_GENESIS_BLOCK = 1296688602 MAX_FUTURE_BLOCK_TIME = 2 * 60 * 60 # Coinbase transaction outputs can only be spent after this number of new blocks (network rule) COINBASE_MATURITY = 100 # From BIP141 WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed" NORMAL_GBT_REQUEST_PARAMS = {"rules": ["segwit"]} VERSIONBITS_LAST_OLD_BLOCK_VERSION = 4 MIN_BLOCKS_TO_KEEP = 288 def create_block(hashprev=None, coinbase=None, ntime=None, *, version=None, tmpl=None, txlist=None): """Create a block (with regtest difficulty).""" block = CBlock() if tmpl is None: tmpl = {} block.nVersion = version or tmpl.get('version') or VERSIONBITS_LAST_OLD_BLOCK_VERSION block.nTime = ntime or tmpl.get('curtime') or int(time.time() + 600) block.hashPrevBlock = hashprev or int(tmpl['previousblockhash'], 0x10) if tmpl and tmpl.get('bits') is not None: block.nBits = struct.unpack('>I', bytes.fromhex(tmpl['bits']))[0] else: block.nBits = 0x207fffff # difficulty retargeting is disabled in REGTEST chainparams if coinbase is None: coinbase = create_coinbase(height=tmpl['height']) block.vtx.append(coinbase) if txlist: for tx in txlist: if not hasattr(tx, 'calc_sha256'): tx = tx_from_hex(tx) block.vtx.append(tx) block.hashMerkleRoot = block.calc_merkle_root() block.calc_sha256() return block def get_witness_script(witness_root, witness_nonce): witness_commitment = uint256_from_str(hash256(ser_uint256(witness_root) + ser_uint256(witness_nonce))) output_data = WITNESS_COMMITMENT_HEADER + ser_uint256(witness_commitment) return CScript([OP_RETURN, output_data]) def add_witness_commitment(block, nonce=0): """Add a witness commitment to the block's coinbase transaction. According to BIP141, blocks with witness rules active must commit to the hash of all in-block transactions including witness.""" # First calculate the merkle root of the block's # transactions, with witnesses. witness_nonce = nonce witness_root = block.calc_witness_merkle_root() # witness_nonce should go to coinbase witness. block.vtx[0].wit.vtxinwit = [CTxInWitness()] block.vtx[0].wit.vtxinwit[0].scriptWitness.stack = [ser_uint256(witness_nonce)] # witness commitment is the last OP_RETURN output in coinbase block.vtx[0].vout.append(CTxOut(0, get_witness_script(witness_root, witness_nonce))) block.vtx[0].rehash() block.hashMerkleRoot = block.calc_merkle_root() block.rehash() def script_BIP34_coinbase_height(height): if height <= 16: res = CScriptOp.encode_op_n(height) # Append dummy to increase scriptSig size above 2 (see bad-cb-length consensus rule) return CScript([res, OP_1]) return CScript([CScriptNum(height)]) def create_coinbase(height, pubkey=None, *, script_pubkey=None, extra_output_script=None, fees=0, nValue=50): """Create a coinbase transaction. If pubkey is passed in, the coinbase output will be a P2PK output; otherwise an anyone-can-spend output. If extra_output_script is given, make a 0-value output to that script. This is useful to pad block weight/sigops as needed. """ coinbase = CTransaction() coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff), script_BIP34_coinbase_height(height), SEQUENCE_FINAL)) coinbaseoutput = CTxOut() coinbaseoutput.nValue = nValue * COIN if nValue == 50: halvings = int(height / 150) # regtest coinbaseoutput.nValue >>= halvings coinbaseoutput.nValue += fees if pubkey is not None: coinbaseoutput.scriptPubKey = key_to_p2pk_script(pubkey) elif script_pubkey is not None: coinbaseoutput.scriptPubKey = script_pubkey else: coinbaseoutput.scriptPubKey = CScript([OP_TRUE]) coinbase.vout = [coinbaseoutput] if extra_output_script is not None: coinbaseoutput2 = CTxOut() coinbaseoutput2.nValue = 0 coinbaseoutput2.scriptPubKey = extra_output_script coinbase.vout.append(coinbaseoutput2) coinbase.calc_sha256() return coinbase def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, output_script=None): """Return one-input, one-output transaction object spending the prevtx's n-th output with the given amount. Can optionally pass scriptPubKey and scriptSig, default is anyone-can-spend output. """ if output_script is None: output_script = CScript() tx = CTransaction() assert n < len(prevtx.vout) tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), script_sig, SEQUENCE_FINAL)) tx.vout.append(CTxOut(amount, output_script)) tx.calc_sha256() return tx def get_legacy_sigopcount_block(block, accurate=True): count = 0 for tx in block.vtx: count += get_legacy_sigopcount_tx(tx, accurate) return count def get_legacy_sigopcount_tx(tx, accurate=True): count = 0 for i in tx.vout: count += i.scriptPubKey.GetSigOpCount(accurate) for j in tx.vin: # scriptSig might be of type bytes, so convert to CScript for the moment count += CScript(j.scriptSig).GetSigOpCount(accurate) return count def witness_script(use_p2wsh, pubkey): """Create a scriptPubKey for a pay-to-witness TxOut. This is either a P2WPKH output for the given pubkey, or a P2WSH output of a 1-of-1 multisig for the given pubkey. Returns the hex encoding of the scriptPubKey.""" if not use_p2wsh: # P2WPKH instead pkscript = key_to_p2wpkh_script(pubkey) else: # 1-of-1 multisig witness_script = keys_to_multisig_script([pubkey]) pkscript = script_to_p2wsh_script(witness_script) return pkscript.hex() def create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount): """Return a transaction (in hex) that spends the given utxo to a segwit output. Optionally wrap the segwit output using P2SH.""" if use_p2wsh: program = keys_to_multisig_script([pubkey]) addr = script_to_p2sh_p2wsh(program) if encode_p2sh else script_to_p2wsh(program) else: addr = key_to_p2sh_p2wpkh(pubkey) if encode_p2sh else key_to_p2wpkh(pubkey) if not encode_p2sh: assert_equal(address_to_scriptpubkey(addr).hex(), witness_script(use_p2wsh, pubkey)) return node.createrawtransaction([utxo], {addr: amount}) def send_to_witness(use_p2wsh, node, utxo, pubkey, encode_p2sh, amount, sign=True, insert_redeem_script=""): """Create a transaction spending a given utxo to a segwit output. The output corresponds to the given pubkey: use_p2wsh determines whether to use P2WPKH or P2WSH; encode_p2sh determines whether to wrap in P2SH. sign=True will have the given node sign the transaction. insert_redeem_script will be added to the scriptSig, if given.""" tx_to_witness = create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount) if (sign): signed = node.signrawtransactionwithwallet(tx_to_witness) assert "errors" not in signed or len(["errors"]) == 0 return node.sendrawtransaction(signed["hex"]) else: if (insert_redeem_script): tx = tx_from_hex(tx_to_witness) tx.vin[0].scriptSig += CScript([bytes.fromhex(insert_redeem_script)]) tx_to_witness = tx.serialize().hex() return node.sendrawtransaction(tx_to_witness) class TestFrameworkBlockTools(unittest.TestCase): def test_create_coinbase(self): height = 20 coinbase_tx = create_coinbase(height=height) assert_equal(CScriptNum.decode(coinbase_tx.vin[0].scriptSig), height)