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530 lines
26 KiB
530 lines
26 KiB
# Copyright (C) 2018 The Electrum developers |
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# Distributed under the MIT software license, see the accompanying |
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# file LICENCE or http://www.opensource.org/licenses/mit-license.php |
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from typing import Optional, Dict, List, Tuple, TYPE_CHECKING, NamedTuple |
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from enum import Enum, auto |
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from .util import bfh, bh2u |
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from .bitcoin import TYPE_ADDRESS, redeem_script_to_address, dust_threshold |
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from . import ecc |
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from .lnutil import (make_commitment_output_to_remote_address, make_commitment_output_to_local_witness_script, |
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derive_privkey, derive_pubkey, derive_blinded_pubkey, derive_blinded_privkey, |
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make_htlc_tx_witness, make_htlc_tx_with_open_channel, UpdateAddHtlc, |
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LOCAL, REMOTE, make_htlc_output_witness_script, UnknownPaymentHash, |
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get_ordered_channel_configs, privkey_to_pubkey, get_per_commitment_secret_from_seed, |
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RevocationStore, extract_ctn_from_tx_and_chan, UnableToDeriveSecret, SENT, RECEIVED) |
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from .transaction import Transaction, TxOutput, construct_witness |
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from .simple_config import estimate_fee |
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from .logging import get_logger |
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if TYPE_CHECKING: |
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from .lnchannel import Channel |
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_logger = get_logger(__name__) |
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def create_sweeptxs_for_watchtower(chan: 'Channel', ctx: Transaction, per_commitment_secret: bytes, |
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sweep_address: str) -> Dict[str,Transaction]: |
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"""Presign sweeping transactions using the just received revoked pcs. |
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These will only be utilised if the remote breaches. |
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Sweep 'to_local', and all the HTLCs (two cases: directly from ctx, or from HTLC tx). |
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""" |
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# prep |
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pcp = ecc.ECPrivkey(per_commitment_secret).get_public_key_bytes(compressed=True) |
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this_conf, other_conf = get_ordered_channel_configs(chan=chan, for_us=False) |
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other_revocation_privkey = derive_blinded_privkey(other_conf.revocation_basepoint.privkey, |
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per_commitment_secret) |
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to_self_delay = other_conf.to_self_delay |
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this_delayed_pubkey = derive_pubkey(this_conf.delayed_basepoint.pubkey, pcp) |
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txs = [] |
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# to_local |
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revocation_pubkey = ecc.ECPrivkey(other_revocation_privkey).get_public_key_bytes(compressed=True) |
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witness_script = bh2u(make_commitment_output_to_local_witness_script( |
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revocation_pubkey, to_self_delay, this_delayed_pubkey)) |
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to_local_address = redeem_script_to_address('p2wsh', witness_script) |
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output_idx = ctx.get_output_idx_from_address(to_local_address) |
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if output_idx is not None: |
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sweep_tx = create_sweeptx_ctx_to_local( |
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sweep_address=sweep_address, |
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ctx=ctx, |
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output_idx=output_idx, |
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witness_script=witness_script, |
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privkey=other_revocation_privkey, |
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is_revocation=True) |
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if sweep_tx: |
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txs.append(sweep_tx) |
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# HTLCs |
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def create_sweeptx_for_htlc(htlc: 'UpdateAddHtlc', is_received_htlc: bool) -> Tuple[Optional[Transaction], |
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Optional[Transaction], |
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Transaction]: |
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htlc_tx_witness_script, htlc_tx = make_htlc_tx_with_open_channel(chan=chan, |
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pcp=pcp, |
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for_us=False, |
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we_receive=not is_received_htlc, |
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commit=ctx, |
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htlc=htlc) |
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return create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( |
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'sweep_from_their_ctx_htlc_', |
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to_self_delay=0, |
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htlc_tx=htlc_tx, |
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htlctx_witness_script=htlc_tx_witness_script, |
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sweep_address=sweep_address, |
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privkey=other_revocation_privkey, |
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is_revocation=True) |
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ctn = extract_ctn_from_tx_and_chan(ctx, chan) |
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# received HTLCs, in their ctx |
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received_htlcs = chan.included_htlcs(REMOTE, RECEIVED, ctn) |
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for htlc in received_htlcs: |
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secondstage_sweep_tx = create_sweeptx_for_htlc(htlc, is_received_htlc=True) |
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if secondstage_sweep_tx: |
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txs.append(secondstage_sweep_tx) |
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# offered HTLCs, in their ctx |
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offered_htlcs = chan.included_htlcs(REMOTE, SENT, ctn) |
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for htlc in offered_htlcs: |
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secondstage_sweep_tx = create_sweeptx_for_htlc(htlc, is_received_htlc=False) |
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if secondstage_sweep_tx: |
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txs.append(secondstage_sweep_tx) |
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return txs |
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def create_sweeptx_for_their_revoked_ctx(chan: 'Channel', ctx: Transaction, per_commitment_secret: bytes, |
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sweep_address: str) -> Dict[str,Transaction]: |
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# prep |
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pcp = ecc.ECPrivkey(per_commitment_secret).get_public_key_bytes(compressed=True) |
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this_conf, other_conf = get_ordered_channel_configs(chan=chan, for_us=False) |
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other_revocation_privkey = derive_blinded_privkey(other_conf.revocation_basepoint.privkey, |
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per_commitment_secret) |
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to_self_delay = other_conf.to_self_delay |
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this_delayed_pubkey = derive_pubkey(this_conf.delayed_basepoint.pubkey, pcp) |
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txs = [] |
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# to_local |
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revocation_pubkey = ecc.ECPrivkey(other_revocation_privkey).get_public_key_bytes(compressed=True) |
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witness_script = bh2u(make_commitment_output_to_local_witness_script( |
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revocation_pubkey, to_self_delay, this_delayed_pubkey)) |
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to_local_address = redeem_script_to_address('p2wsh', witness_script) |
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output_idx = ctx.get_output_idx_from_address(to_local_address) |
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if output_idx is not None: |
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sweep_tx = lambda: create_sweeptx_ctx_to_local( |
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sweep_address=sweep_address, |
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ctx=ctx, |
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output_idx=output_idx, |
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witness_script=witness_script, |
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privkey=other_revocation_privkey, |
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is_revocation=True) |
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return sweep_tx |
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def create_sweeptx_for_their_revoked_htlc(chan: 'Channel', ctx: Transaction, htlc_tx: Transaction, |
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sweep_address: str) -> Dict[str,Transaction]: |
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x = analyze_ctx(chan, ctx) |
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if not x: |
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return |
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ctn, their_pcp, is_revocation, per_commitment_secret = x |
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if not is_revocation: |
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return |
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# prep |
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pcp = ecc.ECPrivkey(per_commitment_secret).get_public_key_bytes(compressed=True) |
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this_conf, other_conf = get_ordered_channel_configs(chan=chan, for_us=False) |
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other_revocation_privkey = derive_blinded_privkey(other_conf.revocation_basepoint.privkey, |
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per_commitment_secret) |
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to_self_delay = other_conf.to_self_delay |
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this_delayed_pubkey = derive_pubkey(this_conf.delayed_basepoint.pubkey, pcp) |
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# same witness script as to_local |
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revocation_pubkey = ecc.ECPrivkey(other_revocation_privkey).get_public_key_bytes(compressed=True) |
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witness_script = bh2u(make_commitment_output_to_local_witness_script( |
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revocation_pubkey, to_self_delay, this_delayed_pubkey)) |
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htlc_address = redeem_script_to_address('p2wsh', witness_script) |
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# check that htlc_tx is a htlc |
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if htlc_tx.outputs()[0].address != htlc_address: |
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return |
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gen_tx = lambda: create_sweeptx_ctx_to_local( |
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sweep_address=sweep_address, |
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ctx=htlc_tx, |
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output_idx=0, |
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witness_script=witness_script, |
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privkey=other_revocation_privkey, |
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is_revocation=True) |
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return 'redeem_htlc2', 0, 0, gen_tx |
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def create_sweeptxs_for_our_ctx(chan: 'Channel', ctx: Transaction, ctn: int, |
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sweep_address: str) -> Dict[str,Transaction]: |
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"""Handle the case where we force close unilaterally with our latest ctx. |
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Construct sweep txns for 'to_local', and for all HTLCs (2 txns each). |
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'to_local' can be swept even if this is a breach (by us), |
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but HTLCs cannot (old HTLCs are no longer stored). |
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""" |
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ctn = extract_ctn_from_tx_and_chan(ctx, chan) |
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our_conf, their_conf = get_ordered_channel_configs(chan=chan, for_us=True) |
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our_per_commitment_secret = get_per_commitment_secret_from_seed( |
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our_conf.per_commitment_secret_seed, RevocationStore.START_INDEX - ctn) |
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our_pcp = ecc.ECPrivkey(our_per_commitment_secret).get_public_key_bytes(compressed=True) |
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our_delayed_bp_privkey = ecc.ECPrivkey(our_conf.delayed_basepoint.privkey) |
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our_localdelayed_privkey = derive_privkey(our_delayed_bp_privkey.secret_scalar, our_pcp) |
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our_localdelayed_privkey = ecc.ECPrivkey.from_secret_scalar(our_localdelayed_privkey) |
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their_revocation_pubkey = derive_blinded_pubkey(their_conf.revocation_basepoint.pubkey, our_pcp) |
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to_self_delay = their_conf.to_self_delay |
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our_htlc_privkey = derive_privkey(secret=int.from_bytes(our_conf.htlc_basepoint.privkey, 'big'), |
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per_commitment_point=our_pcp).to_bytes(32, 'big') |
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our_localdelayed_pubkey = our_localdelayed_privkey.get_public_key_bytes(compressed=True) |
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to_local_witness_script = bh2u(make_commitment_output_to_local_witness_script( |
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their_revocation_pubkey, to_self_delay, our_localdelayed_pubkey)) |
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to_local_address = redeem_script_to_address('p2wsh', to_local_witness_script) |
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their_payment_pubkey = derive_pubkey(their_conf.payment_basepoint.pubkey, our_pcp) |
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to_remote_address = make_commitment_output_to_remote_address(their_payment_pubkey) |
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# test ctx |
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_logger.debug(f'testing our ctx: {to_local_address} {to_remote_address}') |
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if ctx.get_output_idx_from_address(to_local_address) is None\ |
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and ctx.get_output_idx_from_address(to_remote_address) is None: |
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return |
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# we have to_local, to_remote. |
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# other outputs are htlcs |
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# if they are spent, we need to generate the script |
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# so, second-stage htlc sweep should not be returned here |
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if ctn < chan.get_oldest_unrevoked_ctn(LOCAL): |
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_logger.info("we breached.") |
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return {} |
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txs = {} |
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# to_local |
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output_idx = ctx.get_output_idx_from_address(to_local_address) |
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if output_idx is not None: |
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sweep_tx = lambda: create_sweeptx_ctx_to_local( |
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sweep_address=sweep_address, |
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ctx=ctx, |
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output_idx=output_idx, |
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witness_script=to_local_witness_script, |
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privkey=our_localdelayed_privkey.get_secret_bytes(), |
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is_revocation=False, |
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to_self_delay=to_self_delay) |
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prevout = ctx.txid() + ':%d'%output_idx |
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txs[prevout] = ('our_ctx_to_local', to_self_delay, 0, sweep_tx) |
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# HTLCs |
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def create_txns_for_htlc(htlc: 'UpdateAddHtlc', is_received_htlc: bool) -> Tuple[Optional[Transaction], Optional[Transaction]]: |
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if is_received_htlc: |
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try: |
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preimage = chan.lnworker.get_preimage(htlc.payment_hash) |
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except UnknownPaymentHash as e: |
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_logger.info(f'trying to sweep htlc from our latest ctx but getting {repr(e)}') |
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return None, None |
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else: |
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preimage = None |
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htlctx_witness_script, htlc_tx = create_htlctx_that_spends_from_our_ctx( |
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chan=chan, |
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our_pcp=our_pcp, |
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ctx=ctx, |
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htlc=htlc, |
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local_htlc_privkey=our_htlc_privkey, |
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preimage=preimage, |
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is_received_htlc=is_received_htlc) |
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sweep_tx = lambda: create_sweeptx_that_spends_htlctx_that_spends_htlc_in_ctx( |
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'our_ctx_htlc_', |
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to_self_delay=to_self_delay, |
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htlc_tx=htlc_tx, |
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htlctx_witness_script=htlctx_witness_script, |
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sweep_address=sweep_address, |
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privkey=our_localdelayed_privkey.get_secret_bytes(), |
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is_revocation=False) |
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# side effect |
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txs[htlc_tx.prevout(0)] = ('first-stage-htlc', 0, htlc_tx.cltv_expiry, lambda: htlc_tx) |
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txs[htlc_tx.txid() + ':0'] = ('second-stage-htlc', to_self_delay, 0, sweep_tx) |
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# offered HTLCs, in our ctx --> "timeout" |
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# received HTLCs, in our ctx --> "success" |
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offered_htlcs = chan.included_htlcs(LOCAL, SENT, ctn) # type: List[UpdateAddHtlc] |
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received_htlcs = chan.included_htlcs(LOCAL, RECEIVED, ctn) # type: List[UpdateAddHtlc] |
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for htlc in offered_htlcs: |
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create_txns_for_htlc(htlc, is_received_htlc=False) |
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for htlc in received_htlcs: |
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create_txns_for_htlc(htlc, is_received_htlc=True) |
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return txs |
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def analyze_ctx(chan: 'Channel', ctx: Transaction): |
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# note: the remote sometimes has two valid non-revoked commitment transactions, |
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# either of which could be broadcast |
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our_conf, their_conf = get_ordered_channel_configs(chan=chan, for_us=True) |
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ctn = extract_ctn_from_tx_and_chan(ctx, chan) |
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per_commitment_secret = None |
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oldest_unrevoked_remote_ctn = chan.get_oldest_unrevoked_ctn(REMOTE) |
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if ctn == oldest_unrevoked_remote_ctn: |
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their_pcp = their_conf.current_per_commitment_point |
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is_revocation = False |
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elif ctn == oldest_unrevoked_remote_ctn + 1: |
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their_pcp = their_conf.next_per_commitment_point |
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is_revocation = False |
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elif ctn < oldest_unrevoked_remote_ctn: # breach |
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try: |
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per_commitment_secret = their_conf.revocation_store.retrieve_secret(RevocationStore.START_INDEX - ctn) |
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except UnableToDeriveSecret: |
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return |
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their_pcp = ecc.ECPrivkey(per_commitment_secret).get_public_key_bytes(compressed=True) |
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is_revocation = True |
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#_logger.info(f'tx for revoked: {list(txs.keys())}') |
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elif ctn in chan.data_loss_protect_remote_pcp: |
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their_pcp = chan.data_loss_protect_remote_pcp[ctn] |
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is_revocation = False |
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else: |
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return |
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return ctn, their_pcp, is_revocation, per_commitment_secret |
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def create_sweeptxs_for_their_ctx(chan: 'Channel', ctx: Transaction, ctn: int, |
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sweep_address: str) -> Dict[str,Transaction]: |
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"""Handle the case when the remote force-closes with their ctx. |
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Sweep outputs that do not have a CSV delay ('to_remote' and first-stage HTLCs). |
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Outputs with CSV delay ('to_local' and second-stage HTLCs) are redeemed by LNWatcher. |
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""" |
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txs = {} |
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our_conf, their_conf = get_ordered_channel_configs(chan=chan, for_us=True) |
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x = analyze_ctx(chan, ctx) |
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if not x: |
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return |
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ctn, their_pcp, is_revocation, per_commitment_secret = x |
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# to_local and to_remote addresses |
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our_revocation_pubkey = derive_blinded_pubkey(our_conf.revocation_basepoint.pubkey, their_pcp) |
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their_delayed_pubkey = derive_pubkey(their_conf.delayed_basepoint.pubkey, their_pcp) |
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witness_script = bh2u(make_commitment_output_to_local_witness_script( |
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our_revocation_pubkey, our_conf.to_self_delay, their_delayed_pubkey)) |
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to_local_address = redeem_script_to_address('p2wsh', witness_script) |
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our_payment_pubkey = derive_pubkey(our_conf.payment_basepoint.pubkey, their_pcp) |
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to_remote_address = make_commitment_output_to_remote_address(our_payment_pubkey) |
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# test if this is their ctx |
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_logger.debug(f'testing their ctx: {to_local_address} {to_remote_address}') |
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if ctx.get_output_idx_from_address(to_local_address) is None \ |
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and ctx.get_output_idx_from_address(to_remote_address) is None: |
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return |
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if is_revocation: |
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our_revocation_privkey = derive_blinded_privkey(our_conf.revocation_basepoint.privkey, per_commitment_secret) |
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gen_tx = create_sweeptx_for_their_revoked_ctx(chan, ctx, per_commitment_secret, chan.sweep_address) |
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if gen_tx: |
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tx = gen_tx() |
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txs[tx.prevout(0)] = ('to_local_for_revoked_ctx', 0, 0, gen_tx) |
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# prep |
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our_htlc_privkey = derive_privkey(secret=int.from_bytes(our_conf.htlc_basepoint.privkey, 'big'), per_commitment_point=their_pcp) |
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our_htlc_privkey = ecc.ECPrivkey.from_secret_scalar(our_htlc_privkey) |
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their_htlc_pubkey = derive_pubkey(their_conf.htlc_basepoint.pubkey, their_pcp) |
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our_payment_bp_privkey = ecc.ECPrivkey(our_conf.payment_basepoint.privkey) |
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our_payment_privkey = derive_privkey(our_payment_bp_privkey.secret_scalar, their_pcp) |
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our_payment_privkey = ecc.ECPrivkey.from_secret_scalar(our_payment_privkey) |
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assert our_payment_pubkey == our_payment_privkey.get_public_key_bytes(compressed=True) |
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# to_local is handled by lnwatcher |
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# to_remote |
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output_idx = ctx.get_output_idx_from_address(to_remote_address) |
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if output_idx is not None: |
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prevout = ctx.txid() + ':%d'%output_idx |
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sweep_tx = lambda: create_sweeptx_their_ctx_to_remote( |
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sweep_address=sweep_address, |
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ctx=ctx, |
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output_idx=output_idx, |
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our_payment_privkey=our_payment_privkey) |
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txs[prevout] = ('their_ctx_to_remote', 0, 0, sweep_tx) |
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# HTLCs |
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def create_sweeptx_for_htlc(htlc: 'UpdateAddHtlc', is_received_htlc: bool) -> Optional[Transaction]: |
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if not is_received_htlc and not is_revocation: |
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try: |
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preimage = chan.lnworker.get_preimage(htlc.payment_hash) |
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except UnknownPaymentHash as e: |
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_logger.info(f'trying to sweep htlc from their latest ctx but getting {repr(e)}') |
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return None |
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else: |
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preimage = None |
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htlc_output_witness_script = make_htlc_output_witness_script( |
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is_received_htlc=is_received_htlc, |
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remote_revocation_pubkey=our_revocation_pubkey, |
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remote_htlc_pubkey=our_htlc_privkey.get_public_key_bytes(compressed=True), |
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local_htlc_pubkey=their_htlc_pubkey, |
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payment_hash=htlc.payment_hash, |
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cltv_expiry=htlc.cltv_expiry) |
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htlc_address = redeem_script_to_address('p2wsh', bh2u(htlc_output_witness_script)) |
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# FIXME handle htlc_address collision |
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# also: https://github.com/lightningnetwork/lightning-rfc/issues/448 |
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output_idx = ctx.get_output_idx_from_address(htlc_address) |
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if output_idx is not None: |
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cltv_expiry = htlc.cltv_expiry if is_received_htlc and not is_revocation else 0 |
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prevout = ctx.txid() + ':%d'%output_idx |
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sweep_tx = lambda: create_sweeptx_their_ctx_htlc( |
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ctx=ctx, |
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witness_script=htlc_output_witness_script, |
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sweep_address=sweep_address, |
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preimage=preimage, |
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output_idx=output_idx, |
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privkey=our_revocation_privkey if is_revocation else our_htlc_privkey.get_secret_bytes(), |
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is_revocation=is_revocation, |
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cltv_expiry=cltv_expiry) |
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name = f'their_ctx_htlc_{output_idx}' |
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txs[prevout] = (name, 0, cltv_expiry, sweep_tx) |
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# received HTLCs, in their ctx --> "timeout" |
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received_htlcs = chan.included_htlcs(REMOTE, RECEIVED, ctn=ctn) # type: List[UpdateAddHtlc] |
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for htlc in received_htlcs: |
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create_sweeptx_for_htlc(htlc, is_received_htlc=True) |
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# offered HTLCs, in their ctx --> "success" |
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offered_htlcs = chan.included_htlcs(REMOTE, SENT, ctn=ctn) # type: List[UpdateAddHtlc] |
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for htlc in offered_htlcs: |
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create_sweeptx_for_htlc(htlc, is_received_htlc=False) |
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return txs |
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|
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def create_htlctx_that_spends_from_our_ctx(chan: 'Channel', our_pcp: bytes, |
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ctx: Transaction, htlc: 'UpdateAddHtlc', |
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local_htlc_privkey: bytes, preimage: Optional[bytes], |
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is_received_htlc: bool) -> Tuple[bytes, Transaction]: |
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assert is_received_htlc == bool(preimage), 'preimage is required iff htlc is received' |
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preimage = preimage or b'' |
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witness_script, htlc_tx = make_htlc_tx_with_open_channel(chan=chan, |
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pcp=our_pcp, |
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for_us=True, |
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we_receive=is_received_htlc, |
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commit=ctx, |
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htlc=htlc, |
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name=f'our_ctx_htlc_tx_{bh2u(htlc.payment_hash)}', |
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cltv_expiry=0 if is_received_htlc else htlc.cltv_expiry) |
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remote_htlc_sig = chan.get_remote_htlc_sig_for_htlc(htlc, we_receive=is_received_htlc, ctx=ctx) |
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local_htlc_sig = bfh(htlc_tx.sign_txin(0, local_htlc_privkey)) |
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txin = htlc_tx.inputs()[0] |
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witness_program = bfh(Transaction.get_preimage_script(txin)) |
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txin['witness'] = bh2u(make_htlc_tx_witness(remote_htlc_sig, local_htlc_sig, preimage, witness_program)) |
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return witness_script, htlc_tx |
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|
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def create_sweeptx_their_ctx_htlc(ctx: Transaction, witness_script: bytes, sweep_address: str, |
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preimage: Optional[bytes], output_idx: int, |
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privkey: bytes, is_revocation: bool, |
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cltv_expiry: int) -> Optional[Transaction]: |
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assert type(cltv_expiry) is int |
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preimage = preimage or b'' # preimage is required iff (not is_revocation and htlc is offered) |
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val = ctx.outputs()[output_idx].value |
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sweep_inputs = [{ |
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'scriptSig': '', |
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'type': 'p2wsh', |
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'signatures': [], |
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'num_sig': 0, |
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'prevout_n': output_idx, |
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'prevout_hash': ctx.txid(), |
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'value': val, |
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'coinbase': False, |
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'preimage_script': bh2u(witness_script), |
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}] |
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tx_size_bytes = 200 # TODO (depends on offered/received and is_revocation) |
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fee = estimate_fee(tx_size_bytes) |
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outvalue = val - fee |
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if outvalue <= dust_threshold(): return None |
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sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] |
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tx = Transaction.from_io(sweep_inputs, sweep_outputs, version=2 |
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, name=f'their_ctx_htlc_{output_idx}' |
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# note that cltv_expiry, and therefore also locktime will be zero when breach! |
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, cltv_expiry=cltv_expiry, locktime=cltv_expiry) |
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sig = bfh(tx.sign_txin(0, privkey)) |
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if not is_revocation: |
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witness = construct_witness([sig, preimage, witness_script]) |
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else: |
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revocation_pubkey = privkey_to_pubkey(privkey) |
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witness = construct_witness([sig, revocation_pubkey, witness_script]) |
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tx.inputs()[0]['witness'] = witness |
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assert tx.is_complete() |
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return tx |
|
|
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|
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def create_sweeptx_their_ctx_to_remote(sweep_address: str, ctx: Transaction, output_idx: int, |
|
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 = [{ |
|
'type': 'p2wpkh', |
|
'x_pubkeys': [our_payment_pubkey], |
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'num_sig': 1, |
|
'prevout_n': output_idx, |
|
'prevout_hash': ctx.txid(), |
|
'value': val, |
|
'coinbase': False, |
|
'signatures': [None], |
|
}] |
|
tx_size_bytes = 110 # approx size of p2wpkh->p2wpkh |
|
fee = estimate_fee(tx_size_bytes) |
|
outvalue = val - fee |
|
if outvalue <= dust_threshold(): return None |
|
sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] |
|
sweep_tx = Transaction.from_io(sweep_inputs, sweep_outputs, name='their_ctx_to_remote') |
|
sweep_tx.set_rbf(True) |
|
sweep_tx.sign({our_payment_pubkey: (our_payment_privkey.get_secret_bytes(), True)}) |
|
if not sweep_tx.is_complete(): |
|
raise Exception('channel close sweep tx is not complete') |
|
return sweep_tx |
|
|
|
|
|
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) -> Optional[Transaction]: |
|
"""Create a txn that sweeps the 'to_local' output of a commitment |
|
transaction into our wallet. |
|
|
|
privkey: either revocation_privkey or localdelayed_privkey |
|
is_revocation: tells us which ^ |
|
""" |
|
val = ctx.outputs()[output_idx].value |
|
sweep_inputs = [{ |
|
'scriptSig': '', |
|
'type': 'p2wsh', |
|
'signatures': [], |
|
'num_sig': 0, |
|
'prevout_n': output_idx, |
|
'prevout_hash': ctx.txid(), |
|
'value': val, |
|
'coinbase': False, |
|
'preimage_script': witness_script, |
|
}] |
|
if not is_revocation: |
|
assert isinstance(to_self_delay, int) |
|
sweep_inputs[0]['sequence'] = to_self_delay |
|
tx_size_bytes = 121 # approx size of to_local -> p2wpkh |
|
fee = estimate_fee(tx_size_bytes) |
|
outvalue = val - fee |
|
if outvalue <= dust_threshold(): |
|
return None |
|
sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] |
|
name = 'their_ctx_to_local' if is_revocation else 'our_ctx_to_local' |
|
csv_delay = 0 if is_revocation else to_self_delay |
|
sweep_tx = Transaction.from_io(sweep_inputs, sweep_outputs, version=2, name=name, csv_delay=csv_delay) |
|
sig = sweep_tx.sign_txin(0, privkey) |
|
witness = construct_witness([sig, int(is_revocation), witness_script]) |
|
sweep_tx.inputs()[0]['witness'] = witness |
|
return sweep_tx |
|
|
|
|
|
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) -> Optional[Transaction]: |
|
val = htlc_tx.outputs()[0].value |
|
sweep_inputs = [{ |
|
'scriptSig': '', |
|
'type': 'p2wsh', |
|
'signatures': [], |
|
'num_sig': 0, |
|
'prevout_n': 0, |
|
'prevout_hash': htlc_tx.txid(), |
|
'value': val, |
|
'coinbase': False, |
|
'preimage_script': bh2u(htlctx_witness_script), |
|
}] |
|
if not is_revocation: |
|
assert isinstance(to_self_delay, int) |
|
sweep_inputs[0]['sequence'] = to_self_delay |
|
tx_size_bytes = 200 # TODO |
|
fee = estimate_fee(tx_size_bytes) |
|
outvalue = val - fee |
|
if outvalue <= dust_threshold(): return None |
|
sweep_outputs = [TxOutput(TYPE_ADDRESS, sweep_address, outvalue)] |
|
name = name_prefix + htlc_tx.txid()[0:4] |
|
tx = Transaction.from_io(sweep_inputs, sweep_outputs, version=2, name=name, csv_delay=to_self_delay) |
|
|
|
sig = bfh(tx.sign_txin(0, privkey)) |
|
witness = construct_witness([sig, int(is_revocation), htlctx_witness_script]) |
|
tx.inputs()[0]['witness'] = witness |
|
assert tx.is_complete() |
|
return tx
|
|
|