AaronFiore/electrum
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swaps: more precise tx size estimation for claim tx when RBF-ing

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This commit is contained in:
SomberNight
2022-03-31 20:45:05 +02:00
parent 357aaff582
commit e36d7fed7d
3 changed files with 35 additions and 7 deletions
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30
electrum/submarine_swaps.py
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@@ -11,7 +11,7 @@ from .crypto import sha256, hash_160
from .ecc import ECPrivkey
from .bitcoin import (script_to_p2wsh, opcodes, p2wsh_nested_script, push_script,
is_segwit_address, construct_witness)
from .transaction import PartialTxInput, PartialTxOutput, PartialTransaction
from .transaction import PartialTxInput, PartialTxOutput, PartialTransaction, Transaction, TxInput
from .transaction import script_GetOp, match_script_against_template, OPPushDataGeneric, OPPushDataPubkey
from .util import log_exceptions
from .lnutil import REDEEM_AFTER_DOUBLE_SPENT_DELAY, ln_dummy_address
@@ -246,7 +246,7 @@ class SwapManager(Logger):
assert self.lnwatcher
privkey = os.urandom(32)
pubkey = ECPrivkey(privkey).get_public_key_bytes(compressed=True)
lnaddr, invoice = await self.lnworker.create_invoice(
lnaddr, invoice = self.lnworker.create_invoice(
amount_msat=lightning_amount_sat * 1000,
message='swap',
expiry=3600 * 24,
@@ -535,9 +535,12 @@ class SwapManager(Logger):
send_amount += self.get_claim_fee()
return send_amount
def get_swap_by_tx(self, tx):
def get_swap_by_tx(self, tx: Transaction) -> Optional[SwapData]:
# determine if tx is spending from a swap
txin = tx.inputs()[0]
return self.get_swap_by_claim_txin(txin)
def get_swap_by_claim_txin(self, txin: TxInput) -> Optional[SwapData]:
for key, swap in self.swaps.items():
if txin.prevout.txid.hex() == swap.funding_txid:
return swap
@@ -549,10 +552,29 @@ class SwapManager(Logger):
return True
return False
def sign_tx(self, tx, swap):
def add_txin_info(self, txin: PartialTxInput) -> None:
"""Add some info to a claim txin.
note: even without signing, this is useful for tx size estimation.
"""
swap = self.get_swap_by_claim_txin(txin)
if not swap:
return
preimage = swap.preimage if swap.is_reverse else 0
witness_script = swap.redeem_script
txin.script_type = 'p2wsh'
txin.num_sig = 1 # hack so that txin not considered "is_complete"
txin.script_sig = b''
txin.witness_script = witness_script
sig_dummy = b'\x00' * 71 # DER-encoded ECDSA sig, with low S and low R
witness = [sig_dummy, preimage, witness_script]
txin.witness_sizehint = len(bytes.fromhex(construct_witness(witness)))
def sign_tx(self, tx: PartialTransaction, swap: SwapData) -> None:
preimage = swap.preimage if swap.is_reverse else 0
witness_script = swap.redeem_script
txin = tx.inputs()[0]
assert len(tx.inputs()) == 1, f"expected 1 input for swap claim tx. found {len(tx.inputs())}"
assert txin.prevout.txid.hex() == swap.funding_txid
txin.script_type = 'p2wsh'
txin.script_sig = b''
txin.witness_script = witness_script