electrum

Electrum Bitcoin wallet
git clone https://git.parazyd.org/electrum
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commit 81d340b19c461fd82c729f80355f7d8afecaf178
parent 2b04cb3bc45f478c254462a9a9fa766668a7035c
Author: ThomasV <thomasv@electrum.org>
Date:   Thu, 30 May 2019 13:17:17 +0200

lnworker: do not create sweep transactions before outputs can be redeemed

Diffstat:
Melectrum/lnsweep.py | 72++++++++++++++++++++++++++++++------------------------------------------
Melectrum/lnworker.py | 23++++++++++++++---------
Melectrum/simple_config.py | 8++++++++
Melectrum/tests/regtest/regtest.sh | 9+++++++--
4 files changed, 59 insertions(+), 53 deletions(-)

diff --git a/electrum/lnsweep.py b/electrum/lnsweep.py @@ -15,7 +15,7 @@ from .lnutil import (make_commitment_output_to_remote_address, make_commitment_o get_ordered_channel_configs, privkey_to_pubkey, get_per_commitment_secret_from_seed, RevocationStore, extract_ctn_from_tx_and_chan, UnableToDeriveSecret, SENT, RECEIVED) from .transaction import Transaction, TxOutput, construct_witness -from .simple_config import SimpleConfig, FEERATE_FALLBACK_STATIC_FEE +from .simple_config import estimate_fee from .logging import get_logger if TYPE_CHECKING: @@ -190,7 +190,7 @@ def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, to_local_address = redeem_script_to_address('p2wsh', to_local_witness_script) output_idx = ctx.get_output_idx_from_address(to_local_address) if output_idx is not None: - sweep_tx = create_sweeptx_ctx_to_local( + sweep_tx = lambda: create_sweeptx_ctx_to_local( sweep_address=sweep_address, ctx=ctx, output_idx=output_idx, @@ -198,7 +198,8 @@ def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, privkey=our_localdelayed_privkey.get_secret_bytes(), is_revocation=False, to_self_delay=to_self_delay) - txs[sweep_tx.prevout(0)] = sweep_tx + prevout = ctx.txid() + ':%d'%output_idx + txs[prevout] = ('our_ctx_to_local', to_self_delay, 0, sweep_tx) # HTLCs def create_txns_for_htlc(htlc: 'UpdateAddHtlc', is_received_htlc: bool) -> Tuple[Optional[Transaction], Optional[Transaction]]: if is_received_htlc: @@ -217,7 +218,7 @@ def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, local_htlc_privkey=this_htlc_privkey, preimage=preimage, is_received_htlc=is_received_htlc) - to_wallet_tx = create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( + sweep_tx = lambda: create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( 'sweep_from_our_ctx_htlc_', to_self_delay=to_self_delay, htlc_tx=htlc_tx, @@ -225,21 +226,17 @@ def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, sweep_address=sweep_address, privkey=our_localdelayed_privkey.get_secret_bytes(), is_revocation=False) - return htlc_tx, to_wallet_tx + # side effect + txs[htlc_tx.prevout(0)] = ('first-stage-htlc', 0, htlc_tx.cltv_expiry, lambda: htlc_tx) + txs[htlc_tx.txid() + ':0'] = ('second-stage-htlc', to_self_delay, 0, sweep_tx) # offered HTLCs, in our ctx --> "timeout" # received HTLCs, in our ctx --> "success" offered_htlcs = chan.included_htlcs(LOCAL, SENT, ctn) # type: List[UpdateAddHtlc] received_htlcs = chan.included_htlcs(LOCAL, RECEIVED, ctn) # type: List[UpdateAddHtlc] for htlc in offered_htlcs: - htlc_tx, to_wallet_tx = create_txns_for_htlc(htlc, is_received_htlc=False) - if htlc_tx and to_wallet_tx: - txs[to_wallet_tx.prevout(0)] = to_wallet_tx - txs[htlc_tx.prevout(0)] = htlc_tx + create_txns_for_htlc(htlc, is_received_htlc=False) for htlc in received_htlcs: - htlc_tx, to_wallet_tx = create_txns_for_htlc(htlc, is_received_htlc=True) - if htlc_tx and to_wallet_tx: - txs[to_wallet_tx.prevout(0)] = to_wallet_tx - txs[htlc_tx.prevout(0)] = htlc_tx + create_txns_for_htlc(htlc, is_received_htlc=True) return txs @@ -286,12 +283,13 @@ def create_sweeptxs_for_their_ctx(chan: 'Channel', ctx: Transaction, to_remote_address = make_commitment_output_to_remote_address(our_payment_pubkey) output_idx = ctx.get_output_idx_from_address(to_remote_address) if output_idx is not None: - sweep_tx = create_sweeptx_their_ctx_to_remote( + prevout = ctx.txid() + ':%d'%output_idx + sweep_tx = lambda: create_sweeptx_their_ctx_to_remote( sweep_address=sweep_address, ctx=ctx, output_idx=output_idx, our_payment_privkey=other_payment_privkey) - txs[sweep_tx.prevout(0)] = sweep_tx + txs[prevout] = ('their_ctx_to_remote', 0, 0, sweep_tx) # HTLCs def create_sweeptx_for_htlc(htlc: 'UpdateAddHtlc', is_received_htlc: bool) -> Optional[Transaction]: if not is_received_htlc and not is_revocation: @@ -314,7 +312,9 @@ def create_sweeptxs_for_their_ctx(chan: 'Channel', ctx: Transaction, # also: https://github.com/lightningnetwork/lightning-rfc/issues/448 output_idx = ctx.get_output_idx_from_address(htlc_address) if output_idx is not None: - sweep_tx = create_sweeptx_their_ctx_htlc( + cltv_expiry = htlc.cltv_expiry if is_received_htlc and not is_revocation else 0 + prevout = ctx.txid() + ':%d'%output_idx + sweep_tx = lambda: create_sweeptx_their_ctx_htlc( ctx=ctx, witness_script=htlc_output_witness_script, sweep_address=sweep_address, @@ -322,20 +322,17 @@ def create_sweeptxs_for_their_ctx(chan: 'Channel', ctx: Transaction, output_idx=output_idx, privkey=other_revocation_privkey if is_revocation else other_htlc_privkey.get_secret_bytes(), is_revocation=is_revocation, - cltv_expiry=htlc.cltv_expiry if is_received_htlc and not is_revocation else 0) - return sweep_tx + cltv_expiry=cltv_expiry) + name = f'their_ctx_sweep_htlc_{ctx.txid()[:8]}_{output_idx}' + txs[prevout] = (name, 0, cltv_expiry, sweep_tx) # received HTLCs, in their ctx --> "timeout" received_htlcs = chan.included_htlcs(REMOTE, RECEIVED, ctn=ctn) # type: List[UpdateAddHtlc] for htlc in received_htlcs: - sweep_tx = create_sweeptx_for_htlc(htlc, is_received_htlc=True) - if sweep_tx: - txs[sweep_tx.prevout(0)] = sweep_tx + create_sweeptx_for_htlc(htlc, is_received_htlc=True) # offered HTLCs, in their ctx --> "success" offered_htlcs = chan.included_htlcs(REMOTE, SENT, ctn=ctn) # type: List[UpdateAddHtlc] for htlc in offered_htlcs: - sweep_tx = create_sweeptx_for_htlc(htlc, is_received_htlc=False) - if sweep_tx: - txs[sweep_tx.prevout(0)] = sweep_tx + create_sweeptx_for_htlc(htlc, is_received_htlc=False) return txs @@ -363,8 +360,8 @@ def create_htlctx_that_spends_from_our_ctx(chan: 'Channel', our_pcp: bytes, def create_sweeptx_their_ctx_htlc(ctx: Transaction, witness_script: bytes, sweep_address: str, preimage: Optional[bytes], output_idx: int, - privkey: bytes, is_revocation: bool, cltv_expiry: int, - fee_per_kb: int=None) -> Optional[Transaction]: + privkey: bytes, is_revocation: bool, + cltv_expiry: int) -> Optional[Transaction]: assert type(cltv_expiry) is int preimage = preimage or b'' # preimage is required iff (not is_revocation and htlc is offered) val = ctx.outputs()[output_idx].value @@ -380,8 +377,7 @@ def create_sweeptx_their_ctx_htlc(ctx: Transaction, witness_script: bytes, sweep 'preimage_script': bh2u(witness_script), }] tx_size_bytes = 200 # TODO (depends on offered/received and is_revocation) - if fee_per_kb is None: fee_per_kb = FEERATE_FALLBACK_STATIC_FEE - fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes) + fee = estimate_fee(tx_size_bytes) outvalue = val - fee if outvalue <= dust_threshold(): return None sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] @@ -389,7 +385,6 @@ def create_sweeptx_their_ctx_htlc(ctx: Transaction, witness_script: bytes, sweep , name=f'their_ctx_sweep_htlc_{ctx.txid()[:8]}_{output_idx}' # note that cltv_expiry, and therefore also locktime will be zero when breach! , cltv_expiry=cltv_expiry, locktime=cltv_expiry) - sig = bfh(tx.sign_txin(0, privkey)) if not is_revocation: witness = construct_witness([sig, preimage, witness_script]) @@ -402,8 +397,7 @@ def create_sweeptx_their_ctx_htlc(ctx: Transaction, witness_script: bytes, sweep def create_sweeptx_their_ctx_to_remote(sweep_address: str, ctx: Transaction, output_idx: int, - our_payment_privkey: ecc.ECPrivkey, - fee_per_kb: int=None) -> Optional[Transaction]: + our_payment_privkey: ecc.ECPrivkey) -> Optional[Transaction]: our_payment_pubkey = our_payment_privkey.get_public_key_hex(compressed=True) val = ctx.outputs()[output_idx].value sweep_inputs = [{ @@ -417,8 +411,7 @@ def create_sweeptx_their_ctx_to_remote(sweep_address: str, ctx: Transaction, out 'signatures': [None], }] tx_size_bytes = 110 # approx size of p2wpkh->p2wpkh - if fee_per_kb is None: fee_per_kb = FEERATE_FALLBACK_STATIC_FEE - fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes) + fee = estimate_fee(tx_size_bytes) outvalue = val - fee if outvalue <= dust_threshold(): return None sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] @@ -432,8 +425,7 @@ def create_sweeptx_their_ctx_to_remote(sweep_address: str, ctx: Transaction, out def create_sweeptx_ctx_to_local(sweep_address: str, ctx: Transaction, output_idx: int, witness_script: str, privkey: bytes, is_revocation: bool, - to_self_delay: int=None, - fee_per_kb: int=None) -> Optional[Transaction]: + to_self_delay: int=None) -> Optional[Transaction]: """Create a txn that sweeps the 'to_local' output of a commitment transaction into our wallet. @@ -456,9 +448,7 @@ def create_sweeptx_ctx_to_local(sweep_address: str, ctx: Transaction, output_idx assert isinstance(to_self_delay, int) sweep_inputs[0]['sequence'] = to_self_delay tx_size_bytes = 121 # approx size of to_local -> p2wpkh - if fee_per_kb is None: - fee_per_kb = FEERATE_FALLBACK_STATIC_FEE - fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes) + fee = estimate_fee(tx_size_bytes) outvalue = val - fee if outvalue <= dust_threshold(): return None @@ -475,8 +465,7 @@ def create_sweeptx_ctx_to_local(sweep_address: str, ctx: Transaction, output_idx def create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( name_prefix: str, htlc_tx: Transaction, htlctx_witness_script: bytes, sweep_address: str, - privkey: bytes, is_revocation: bool, to_self_delay: int, - fee_per_kb: int=None) -> Optional[Transaction]: + privkey: bytes, is_revocation: bool, to_self_delay: int) -> Optional[Transaction]: val = htlc_tx.outputs()[0].value sweep_inputs = [{ 'scriptSig': '', @@ -493,8 +482,7 @@ def create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( assert isinstance(to_self_delay, int) sweep_inputs[0]['sequence'] = to_self_delay tx_size_bytes = 200 # TODO - if fee_per_kb is None: fee_per_kb = FEERATE_FALLBACK_STATIC_FEE - fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes) + fee = estimate_fee(tx_size_bytes) outvalue = val - fee if outvalue <= dust_threshold(): return None sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] diff --git a/electrum/lnworker.py b/electrum/lnworker.py @@ -529,30 +529,35 @@ class LNWallet(LNWorker): # create and broadcast transaction for prevout, e_tx in chan.sweep_info.items(): + name, csv_delay, cltv_expiry, gen_tx = e_tx if spenders.get(prevout) is not None: self.logger.info(f'outpoint already spent {prevout}') continue prev_txid, prev_index = prevout.split(':') broadcast = True - if e_tx.cltv_expiry: + if cltv_expiry: local_height = self.network.get_local_height() - remaining = e_tx.cltv_expiry - local_height + remaining = cltv_expiry - local_height if remaining > 0: self.logger.info('waiting for {}: CLTV ({} > {}), funding outpoint {} and tx {}' - .format(e_tx.name, local_height, e_tx.cltv_expiry, funding_outpoint[:8], prev_txid[:8])) + .format(name, local_height, cltv_expiry, funding_outpoint[:8], prev_txid[:8])) broadcast = False - if e_tx.csv_delay: + if csv_delay: prev_height = self.network.lnwatcher.get_tx_height(prev_txid) - remaining = e_tx.csv_delay - prev_height.conf + remaining = csv_delay - prev_height.conf if remaining > 0: self.logger.info('waiting for {}: CSV ({} >= {}), funding outpoint {} and tx {}' - .format(e_tx.name, prev_height.conf, e_tx.csv_delay, funding_outpoint[:8], prev_txid[:8])) + .format(name, prev_height.conf, csv_delay, funding_outpoint[:8], prev_txid[:8])) broadcast = False + tx = gen_tx() + if tx is None: + self.logger.info(f'{name} could not claim output: {prevout}, dust') if broadcast: - if not await self.network.lnwatcher.broadcast_or_log(funding_outpoint, e_tx): - self.logger.info(f'{e_tx.name} could not publish encumbered tx: {str(e_tx)}, prevout: {prevout}') + if not await self.network.lnwatcher.broadcast_or_log(funding_outpoint, tx): + self.logger.info(f'{name} could not publish encumbered tx: {str(tx)}, prevout: {prevout}') else: - self.wallet.add_future_tx(e_tx, remaining) + # it's OK to add local transaction, the fee will be recomputed + self.wallet.add_future_tx(tx, remaining) def is_dangerous(self, chan): for x in chan.get_unfulfilled_htlcs(): diff --git a/electrum/simple_config.py b/electrum/simple_config.py @@ -44,6 +44,14 @@ def set_config(c): global config config = c +def estimate_fee(tx_size_bytes): + global config + if config: + fee = config.estimate_fee(tx_size_bytes) + else: + fee_per_kb = FEERATE_FALLBACK_STATIC_FEE + fee = SimpleConfig.estimate_fee_for_feerate(fee_per_kb, tx_size_bytes) + return fee FINAL_CONFIG_VERSION = 3 diff --git a/electrum/tests/regtest/regtest.sh b/electrum/tests/regtest/regtest.sh @@ -132,13 +132,18 @@ if [[ $1 == "redeem_htlcs" ]]; then chan_id=$($alice list_channels | jq -r ".[0].channel_point") $alice close_channel $chan_id --force new_blocks 1 - sleep 5 + sleep 3 echo "alice balance after closing channel:" $($alice getbalance) new_blocks 144 sleep 10 new_blocks 1 + sleep 3 + echo "alice balance after CLTV" $($alice getbalance) + new_blocks 144 sleep 10 - echo "alice balance after 144 blocks:" $($alice getbalance) + new_blocks 1 + sleep 3 + echo "alice balance after CSV" $($alice getbalance) balance_after=$($alice getbalance | jq '[.confirmed, .unconfirmed] | to_entries | map(select(.value != null).value) | map(tonumber) | add ') if (( $(echo "$balance_before - $balance_after > 0.02" | bc -l) )); then echo "htlc not redeemed."