_ Git - rust-lightning/blob - lightning/src/chain/onchaintx.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! The logic to build claims and bump in-flight transactions until confirmations.
  11 //!
  12 //! OnchainTxHandler objects are fully-part of ChannelMonitor and encapsulates all
  13 //! building, tracking, bumping and notifications functions.
  14
  15 use bitcoin::blockdata::transaction::Transaction;
  16 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
  17 use bitcoin::blockdata::script::Script;
  18
  19 use bitcoin::hash_types::Txid;
  20
  21 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
  22 use bitcoin::secp256k1;
  23
  24 use crate::ln::msgs::DecodeError;
  25 use crate::ln::PaymentPreimage;
  26 #[cfg(anchors)]
  27 use crate::ln::chan_utils;
  28 use crate::ln::chan_utils::{ChannelTransactionParameters, HolderCommitmentTransaction};
  29 #[cfg(anchors)]
  30 use crate::chain::chaininterface::ConfirmationTarget;
  31 use crate::chain::chaininterface::{FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator};
  32 use crate::chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER};
  33 use crate::chain::keysinterface::{Sign, KeysInterface};
  34 #[cfg(anchors)]
  35 use crate::chain::package::PackageSolvingData;
  36 use crate::chain::package::PackageTemplate;
  37 use crate::util::logger::Logger;
  38 use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, Writer, Writeable, VecWriter};
  39 use crate::util::byte_utils;
  40
  41 use crate::io;
  42 use crate::prelude::*;
  43 use alloc::collections::BTreeMap;
  44 use core::cmp;
  45 use core::ops::Deref;
  46 use core::mem::replace;
  47 #[cfg(anchors)]
  48 use core::mem::swap;
  49 use bitcoin::hashes::Hash;
  50
  51 const MAX_ALLOC_SIZE: usize = 64*1024;
  52
  53 /// An entry for an [`OnchainEvent`], stating the block height when the event was observed and the
  54 /// transaction causing it.
  55 ///
  56 /// Used to determine when the on-chain event can be considered safe from a chain reorganization.
  57 #[derive(Clone, PartialEq, Eq)]
  58 struct OnchainEventEntry {
  59         txid: Txid,
  60         height: u32,
  61         event: OnchainEvent,
  62 }
  63
  64 impl OnchainEventEntry {
  65         fn confirmation_threshold(&self) -> u32 {
  66                 self.height + ANTI_REORG_DELAY - 1
  67         }
  68
  69         fn has_reached_confirmation_threshold(&self, height: u32) -> bool {
  70                 height >= self.confirmation_threshold()
  71         }
  72 }
  73
  74 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
  75 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
  76 #[derive(Clone, PartialEq, Eq)]
  77 enum OnchainEvent {
  78         /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
  79         /// bump-txn candidate buffer.
  80         Claim {
  81                 claim_request: Txid,
  82         },
  83         /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a counterparty party tx.
  84         /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
  85         /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
  86         ContentiousOutpoint {
  87                 package: PackageTemplate,
  88         }
  89 }
  90
  91 impl Writeable for OnchainEventEntry {
  92         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
  93                 write_tlv_fields!(writer, {
  94                         (0, self.txid, required),
  95                         (2, self.height, required),
  96                         (4, self.event, required),
  97                 });
  98                 Ok(())
  99         }
 100 }
 101
 102 impl MaybeReadable for OnchainEventEntry {
 103         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
 104                 let mut txid = Txid::all_zeros();
 105                 let mut height = 0;
 106                 let mut event = None;
 107                 read_tlv_fields!(reader, {
 108                         (0, txid, required),
 109                         (2, height, required),
 110                         (4, event, ignorable),
 111                 });
 112                 if let Some(ev) = event {
 113                         Ok(Some(Self { txid, height, event: ev }))
 114                 } else {
 115                         Ok(None)
 116                 }
 117         }
 118 }
 119
 120 impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
 121         (0, Claim) => {
 122                 (0, claim_request, required),
 123         },
 124         (1, ContentiousOutpoint) => {
 125                 (0, package, required),
 126         },
 127 );
 128
 129 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 130         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 131                 match Readable::read(reader)? {
 132                         0u8 => Ok(None),
 133                         1u8 => {
 134                                 let vlen: u64 = Readable::read(reader)?;
 135                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::core::mem::size_of::<Option<(usize, Signature)>>()));
 136                                 for _ in 0..vlen {
 137                                         ret.push(match Readable::read(reader)? {
 138                                                 0u8 => None,
 139                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 140                                                 _ => return Err(DecodeError::InvalidValue)
 141                                         });
 142                                 }
 143                                 Ok(Some(ret))
 144                         },
 145                         _ => Err(DecodeError::InvalidValue),
 146                 }
 147         }
 148 }
 149
 150 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 151         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 152                 match self {
 153                         &Some(ref vec) => {
 154                                 1u8.write(writer)?;
 155                                 (vec.len() as u64).write(writer)?;
 156                                 for opt in vec.iter() {
 157                                         match opt {
 158                                                 &Some((ref idx, ref sig)) => {
 159                                                         1u8.write(writer)?;
 160                                                         (*idx as u64).write(writer)?;
 161                                                         sig.write(writer)?;
 162                                                 },
 163                                                 &None => 0u8.write(writer)?,
 164                                         }
 165                                 }
 166                         },
 167                         &None => 0u8.write(writer)?,
 168                 }
 169                 Ok(())
 170         }
 171 }
 172
 173 // Represents the different types of claims for which events are yielded externally to satisfy said
 174 // claims.
 175 #[cfg(anchors)]
 176 pub(crate) enum ClaimEvent {
 177         /// Event yielded to signal that the commitment transaction fee must be bumped to claim any
 178         /// encumbered funds and proceed to HTLC resolution, if any HTLCs exist.
 179         BumpCommitment {
 180                 package_target_feerate_sat_per_1000_weight: u32,
 181                 commitment_tx: Transaction,
 182                 anchor_output_idx: u32,
 183         },
 184 }
 185
 186 /// Represents the different ways an output can be claimed (i.e., spent to an address under our
 187 /// control) onchain.
 188 pub(crate) enum OnchainClaim {
 189         /// A finalized transaction pending confirmation spending the output to claim.
 190         Tx(Transaction),
 191         #[cfg(anchors)]
 192         /// An event yielded externally to signal additional inputs must be added to a transaction
 193         /// pending confirmation spending the output to claim.
 194         Event(ClaimEvent),
 195 }
 196
 197 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 198 /// do RBF bumping if possible.
 199 #[derive(Clone)]
 200 pub struct OnchainTxHandler<ChannelSigner: Sign> {
 201         destination_script: Script,
 202         holder_commitment: HolderCommitmentTransaction,
 203         // holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
 204         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 205         // the set of HTLCs in the HolderCommitmentTransaction.
 206         holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 207         prev_holder_commitment: Option<HolderCommitmentTransaction>,
 208         prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 209
 210         pub(super) signer: ChannelSigner,
 211         pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 212
 213         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 214         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 215         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 216         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 217         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 218         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 219         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 220         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 221         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 222         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 223         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 224         #[cfg(test)] // Used in functional_test to verify sanitization
 225         pub(crate) pending_claim_requests: HashMap<Txid, PackageTemplate>,
 226         #[cfg(not(test))]
 227         pending_claim_requests: HashMap<Txid, PackageTemplate>,
 228         #[cfg(anchors)]
 229         pending_claim_events: HashMap<Txid, ClaimEvent>,
 230
 231         // Used to link outpoints claimed in a connected block to a pending claim request.
 232         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 233         // Value is (pending claim request identifier, confirmation_block), identifier
 234         // is txid of the initial claiming transaction and is immutable until outpoint is
 235         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 236         // block with output gets disconnected.
 237         #[cfg(test)] // Used in functional_test to verify sanitization
 238         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 239         #[cfg(not(test))]
 240         claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 241
 242         locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
 243
 244         onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
 245
 246         pub(super) secp_ctx: Secp256k1<secp256k1::All>,
 247 }
 248
 249 const SERIALIZATION_VERSION: u8 = 1;
 250 const MIN_SERIALIZATION_VERSION: u8 = 1;
 251
 252 impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
 253         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 254                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 255
 256                 self.destination_script.write(writer)?;
 257                 self.holder_commitment.write(writer)?;
 258                 self.holder_htlc_sigs.write(writer)?;
 259                 self.prev_holder_commitment.write(writer)?;
 260                 self.prev_holder_htlc_sigs.write(writer)?;
 261
 262                 self.channel_transaction_parameters.write(writer)?;
 263
 264                 let mut key_data = VecWriter(Vec::new());
 265                 self.signer.write(&mut key_data)?;
 266                 assert!(key_data.0.len() < core::usize::MAX);
 267                 assert!(key_data.0.len() < core::u32::MAX as usize);
 268                 (key_data.0.len() as u32).write(writer)?;
 269                 writer.write_all(&key_data.0[..])?;
 270
 271                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 272                 for (ref ancestor_claim_txid, request) in self.pending_claim_requests.iter() {
 273                         ancestor_claim_txid.write(writer)?;
 274                         request.write(writer)?;
 275                 }
 276
 277                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 278                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 279                         outp.write(writer)?;
 280                         claim_and_height.0.write(writer)?;
 281                         claim_and_height.1.write(writer)?;
 282                 }
 283
 284                 writer.write_all(&byte_utils::be64_to_array(self.locktimed_packages.len() as u64))?;
 285                 for (ref locktime, ref packages) in self.locktimed_packages.iter() {
 286                         locktime.write(writer)?;
 287                         writer.write_all(&byte_utils::be64_to_array(packages.len() as u64))?;
 288                         for ref package in packages.iter() {
 289                                 package.write(writer)?;
 290                         }
 291                 }
 292
 293                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_awaiting_threshold_conf.len() as u64))?;
 294                 for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
 295                         entry.write(writer)?;
 296                 }
 297
 298                 write_tlv_fields!(writer, {});
 299                 Ok(())
 300         }
 301 }
 302
 303 impl<'a, K: KeysInterface> ReadableArgs<&'a K> for OnchainTxHandler<K::Signer> {
 304         fn read<R: io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
 305                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 306
 307                 let destination_script = Readable::read(reader)?;
 308
 309                 let holder_commitment = Readable::read(reader)?;
 310                 let holder_htlc_sigs = Readable::read(reader)?;
 311                 let prev_holder_commitment = Readable::read(reader)?;
 312                 let prev_holder_htlc_sigs = Readable::read(reader)?;
 313
 314                 let channel_parameters = Readable::read(reader)?;
 315
 316                 let keys_len: u32 = Readable::read(reader)?;
 317                 let mut keys_data = Vec::with_capacity(cmp::min(keys_len as usize, MAX_ALLOC_SIZE));
 318                 while keys_data.len() != keys_len as usize {
 319                         // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
 320                         let mut data = [0; 1024];
 321                         let read_slice = &mut data[0..cmp::min(1024, keys_len as usize - keys_data.len())];
 322                         reader.read_exact(read_slice)?;
 323                         keys_data.extend_from_slice(read_slice);
 324                 }
 325                 let signer = keys_manager.read_chan_signer(&keys_data)?;
 326
 327                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 328                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 329                 for _ in 0..pending_claim_requests_len {
 330                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 331                 }
 332
 333                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 334                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 335                 for _ in 0..claimable_outpoints_len {
 336                         let outpoint = Readable::read(reader)?;
 337                         let ancestor_claim_txid = Readable::read(reader)?;
 338                         let height = Readable::read(reader)?;
 339                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 340                 }
 341
 342                 let locktimed_packages_len: u64 = Readable::read(reader)?;
 343                 let mut locktimed_packages = BTreeMap::new();
 344                 for _ in 0..locktimed_packages_len {
 345                         let locktime = Readable::read(reader)?;
 346                         let packages_len: u64 = Readable::read(reader)?;
 347                         let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
 348                         for _ in 0..packages_len {
 349                                 packages.push(Readable::read(reader)?);
 350                         }
 351                         locktimed_packages.insert(locktime, packages);
 352                 }
 353
 354                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 355                 let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 356                 for _ in 0..waiting_threshold_conf_len {
 357                         if let Some(val) = MaybeReadable::read(reader)? {
 358                                 onchain_events_awaiting_threshold_conf.push(val);
 359                         }
 360                 }
 361
 362                 read_tlv_fields!(reader, {});
 363
 364                 let mut secp_ctx = Secp256k1::new();
 365                 secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
 366
 367                 Ok(OnchainTxHandler {
 368                         destination_script,
 369                         holder_commitment,
 370                         holder_htlc_sigs,
 371                         prev_holder_commitment,
 372                         prev_holder_htlc_sigs,
 373                         signer,
 374                         channel_transaction_parameters: channel_parameters,
 375                         claimable_outpoints,
 376                         locktimed_packages,
 377                         pending_claim_requests,
 378                         onchain_events_awaiting_threshold_conf,
 379                         #[cfg(anchors)]
 380                         pending_claim_events: HashMap::new(),
 381                         secp_ctx,
 382                 })
 383         }
 384 }
 385
 386 impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
 387         pub(crate) fn new(destination_script: Script, signer: ChannelSigner, channel_parameters: ChannelTransactionParameters, holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>) -> Self {
 388                 OnchainTxHandler {
 389                         destination_script,
 390                         holder_commitment,
 391                         holder_htlc_sigs: None,
 392                         prev_holder_commitment: None,
 393                         prev_holder_htlc_sigs: None,
 394                         signer,
 395                         channel_transaction_parameters: channel_parameters,
 396                         pending_claim_requests: HashMap::new(),
 397                         claimable_outpoints: HashMap::new(),
 398                         locktimed_packages: BTreeMap::new(),
 399                         onchain_events_awaiting_threshold_conf: Vec::new(),
 400                         #[cfg(anchors)]
 401                         pending_claim_events: HashMap::new(),
 402
 403                         secp_ctx,
 404                 }
 405         }
 406
 407         pub(crate) fn get_prev_holder_commitment_to_self_value(&self) -> Option<u64> {
 408                 self.prev_holder_commitment.as_ref().map(|commitment| commitment.to_broadcaster_value_sat())
 409         }
 410
 411         pub(crate) fn get_cur_holder_commitment_to_self_value(&self) -> u64 {
 412                 self.holder_commitment.to_broadcaster_value_sat()
 413         }
 414
 415         #[cfg(anchors)]
 416         pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<ClaimEvent> {
 417                 let mut ret = HashMap::new();
 418                 swap(&mut ret, &mut self.pending_claim_events);
 419                 ret.into_iter().map(|(_, event)| event).collect::<Vec<_>>()
 420         }
 421
 422         /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
 423         /// onchain) lays on the assumption of claim transactions getting confirmed before timelock
 424         /// expiration (CSV or CLTV following cases). In case of high-fee spikes, claim tx may get stuck
 425         /// in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or
 426         /// Child-Pay-For-Parent.
 427         ///
 428         /// Panics if there are signing errors, because signing operations in reaction to on-chain
 429         /// events are not expected to fail, and if they do, we may lose funds.
 430         fn generate_claim<F: Deref, L: Deref>(&mut self, cur_height: u32, cached_request: &PackageTemplate, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L) -> Option<(Option<u32>, u64, OnchainClaim)>
 431                 where F::Target: FeeEstimator,
 432                                         L::Target: Logger,
 433         {
 434                 if cached_request.outpoints().len() == 0 { return None } // But don't prune pending claiming request yet, we may have to resurrect HTLCs
 435
 436                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 437                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 438                 let new_timer = Some(cached_request.get_height_timer(cur_height));
 439                 if cached_request.is_malleable() {
 440                         let predicted_weight = cached_request.package_weight(&self.destination_script);
 441                         if let Some((output_value, new_feerate)) =
 442                                         cached_request.compute_package_output(predicted_weight, self.destination_script.dust_value().to_sat(), fee_estimator, logger) {
 443                                 assert!(new_feerate != 0);
 444
 445                                 let transaction = cached_request.finalize_malleable_package(self, output_value, self.destination_script.clone(), logger).unwrap();
 446                                 log_trace!(logger, "...with timer {} and feerate {}", new_timer.unwrap(), new_feerate);
 447                                 assert!(predicted_weight >= transaction.weight());
 448                                 return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)))
 449                         }
 450                 } else {
 451                         // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
 452                         // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
 453                         // which require external funding.
 454                         #[cfg(not(anchors))]
 455                         let inputs = cached_request.inputs();
 456                         #[cfg(anchors)]
 457                         let mut inputs = cached_request.inputs();
 458                         debug_assert_eq!(inputs.len(), 1);
 459                         let tx = match cached_request.finalize_untractable_package(self, logger) {
 460                                 Some(tx) => tx,
 461                                 None => return None,
 462                         };
 463                         if !cached_request.requires_external_funding() {
 464                                 return Some((None, 0, OnchainClaim::Tx(tx)));
 465                         }
 466                         #[cfg(anchors)]
 467                         return inputs.find_map(|input| match input {
 468                                 // Commitment inputs with anchors support are the only untractable inputs supported
 469                                 // thus far that require external funding.
 470                                 PackageSolvingData::HolderFundingOutput(..) => {
 471                                         debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(),
 472                                                 "Holder commitment transaction mismatch");
 473                                         // We'll locate an anchor output we can spend within the commitment transaction.
 474                                         let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
 475                                         match chan_utils::get_anchor_output(&tx, funding_pubkey) {
 476                                                 // An anchor output was found, so we should yield a funding event externally.
 477                                                 Some((idx, _)) => {
 478                                                         // TODO: Use a lower confirmation target when both our and the
 479                                                         // counterparty's latest commitment don't have any HTLCs present.
 480                                                         let conf_target = ConfirmationTarget::HighPriority;
 481                                                         let package_target_feerate_sat_per_1000_weight = cached_request
 482                                                                 .compute_package_feerate(fee_estimator, conf_target);
 483                                                         Some((
 484                                                                 new_timer,
 485                                                                 package_target_feerate_sat_per_1000_weight as u64,
 486                                                                 OnchainClaim::Event(ClaimEvent::BumpCommitment {
 487                                                                         package_target_feerate_sat_per_1000_weight,
 488                                                                         commitment_tx: tx.clone(),
 489                                                                         anchor_output_idx: idx,
 490                                                                 }),
 491                                                         ))
 492                                                 },
 493                                                 // An anchor output was not found. There's nothing we can do other than
 494                                                 // attempt to broadcast the transaction with its current fee rate and hope
 495                                                 // it confirms. This is essentially the same behavior as a commitment
 496                                                 // transaction without anchor outputs.
 497                                                 None => Some((None, 0, OnchainClaim::Tx(tx.clone()))),
 498                                         }
 499                                 },
 500                                 _ => {
 501                                         debug_assert!(false, "Only HolderFundingOutput inputs should be untractable and require external funding");
 502                                         None
 503                                 },
 504                         });
 505                 }
 506                 None
 507         }
 508
 509         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 510         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 511         /// Formerly this was named `block_connected`, but it is now also used for claiming an HTLC output
 512         /// if we receive a preimage after force-close.
 513         /// `conf_height` represents the height at which the transactions in `txn_matched` were
 514         /// confirmed. This does not need to equal the current blockchain tip height, which should be
 515         /// provided via `cur_height`, however it must never be higher than `cur_height`.
 516         pub(crate) fn update_claims_view<B: Deref, F: Deref, L: Deref>(&mut self, txn_matched: &[&Transaction], requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L)
 517                 where B::Target: BroadcasterInterface,
 518                       F::Target: FeeEstimator,
 519                                         L::Target: Logger,
 520         {
 521                 log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {} and {} claim requests", cur_height, txn_matched.len(), conf_height, requests.len());
 522                 let mut preprocessed_requests = Vec::with_capacity(requests.len());
 523                 let mut aggregated_request = None;
 524
 525                 // Try to aggregate outputs if their timelock expiration isn't imminent (package timelock
 526                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 527                 for req in requests {
 528                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 529                         if let Some(_) = self.claimable_outpoints.get(req.outpoints()[0]) {
 530                                 log_info!(logger, "Ignoring second claim for outpoint {}:{}, already registered its claiming request", req.outpoints()[0].txid, req.outpoints()[0].vout);
 531                         } else {
 532                                 let timelocked_equivalent_package = self.locktimed_packages.iter().map(|v| v.1.iter()).flatten()
 533                                         .find(|locked_package| locked_package.outpoints() == req.outpoints());
 534                                 if let Some(package) = timelocked_equivalent_package {
 535                                         log_info!(logger, "Ignoring second claim for outpoint {}:{}, we already have one which we're waiting on a timelock at {} for.",
 536                                                 req.outpoints()[0].txid, req.outpoints()[0].vout, package.package_timelock());
 537                                         continue;
 538                                 }
 539
 540                                 if req.package_timelock() > cur_height + 1 {
 541                                         log_info!(logger, "Delaying claim of package until its timelock at {} (current height {}), the following outpoints are spent:", req.package_timelock(), cur_height);
 542                                         for outpoint in req.outpoints() {
 543                                                 log_info!(logger, "  Outpoint {}", outpoint);
 544                                         }
 545                                         self.locktimed_packages.entry(req.package_timelock()).or_insert(Vec::new()).push(req);
 546                                         continue;
 547                                 }
 548
 549                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.timelock(), cur_height + CLTV_SHARED_CLAIM_BUFFER);
 550                                 if req.timelock() <= cur_height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable() {
 551                                         // Don't aggregate if outpoint package timelock is soon or marked as non-aggregable
 552                                         preprocessed_requests.push(req);
 553                                 } else if aggregated_request.is_none() {
 554                                         aggregated_request = Some(req);
 555                                 } else {
 556                                         aggregated_request.as_mut().unwrap().merge_package(req);
 557                                 }
 558                         }
 559                 }
 560                 if let Some(req) = aggregated_request {
 561                         preprocessed_requests.push(req);
 562                 }
 563
 564                 // Claim everything up to and including cur_height + 1
 565                 let remaining_locked_packages = self.locktimed_packages.split_off(&(cur_height + 2));
 566                 for (pop_height, mut entry) in self.locktimed_packages.iter_mut() {
 567                         log_trace!(logger, "Restoring delayed claim of package(s) at their timelock at {}.", pop_height);
 568                         preprocessed_requests.append(&mut entry);
 569                 }
 570                 self.locktimed_packages = remaining_locked_packages;
 571
 572                 // Generate claim transactions and track them to bump if necessary at
 573                 // height timer expiration (i.e in how many blocks we're going to take action).
 574                 for mut req in preprocessed_requests {
 575                         if let Some((new_timer, new_feerate, claim)) = self.generate_claim(cur_height, &req, &*fee_estimator, &*logger) {
 576                                 req.set_timer(new_timer);
 577                                 req.set_feerate(new_feerate);
 578                                 let txid = match claim {
 579                                         OnchainClaim::Tx(tx) => {
 580                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(tx));
 581                                                 broadcaster.broadcast_transaction(&tx);
 582                                                 tx.txid()
 583                                         },
 584                                         #[cfg(anchors)]
 585                                         OnchainClaim::Event(claim_event) => {
 586                                                 log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
 587                                                 let txid = match claim_event {
 588                                                         ClaimEvent::BumpCommitment { ref commitment_tx, .. } => commitment_tx.txid(),
 589                                                 };
 590                                                 self.pending_claim_events.insert(txid, claim_event);
 591                                                 txid
 592                                         },
 593                                 };
 594                                 for k in req.outpoints() {
 595                                         log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 596                                         self.claimable_outpoints.insert(k.clone(), (txid, conf_height));
 597                                 }
 598                                 self.pending_claim_requests.insert(txid, req);
 599                         }
 600                 }
 601
 602                 let mut bump_candidates = HashMap::new();
 603                 for tx in txn_matched {
 604                         // Scan all input to verify is one of the outpoint spent is of interest for us
 605                         let mut claimed_outputs_material = Vec::new();
 606                         for inp in &tx.input {
 607                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 608                                         // If outpoint has claim request pending on it...
 609                                         if let Some(request) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 610                                                 //... we need to verify equality between transaction outpoints and claim request
 611                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 612                                                 // by us.
 613                                                 let mut set_equality = true;
 614                                                 if request.outpoints().len() != tx.input.len() {
 615                                                         set_equality = false;
 616                                                 } else {
 617                                                         for (claim_inp, tx_inp) in request.outpoints().iter().zip(tx.input.iter()) {
 618                                                                 if **claim_inp != tx_inp.previous_output {
 619                                                                         set_equality = false;
 620                                                                 }
 621                                                         }
 622                                                 }
 623
 624                                                 macro_rules! clean_claim_request_after_safety_delay {
 625                                                         () => {
 626                                                                 let entry = OnchainEventEntry {
 627                                                                         txid: tx.txid(),
 628                                                                         height: conf_height,
 629                                                                         event: OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() }
 630                                                                 };
 631                                                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 632                                                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 633                                                                 }
 634                                                         }
 635                                                 }
 636
 637                                                 // If this is our transaction (or our counterparty spent all the outputs
 638                                                 // before we could anyway with same inputs order than us), wait for
 639                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 640                                                 if set_equality {
 641                                                         clean_claim_request_after_safety_delay!();
 642                                                 } else { // If false, generate new claim request with update outpoint set
 643                                                         let mut at_least_one_drop = false;
 644                                                         for input in tx.input.iter() {
 645                                                                 if let Some(package) = request.split_package(&input.previous_output) {
 646                                                                         claimed_outputs_material.push(package);
 647                                                                         at_least_one_drop = true;
 648                                                                 }
 649                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 650                                                                 if request.outpoints().is_empty() {
 651                                                                         clean_claim_request_after_safety_delay!();
 652                                                                 }
 653                                                         }
 654                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 655                                                         if at_least_one_drop {
 656                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), request.clone());
 657                                                         }
 658                                                 }
 659                                                 break; //No need to iterate further, either tx is our or their
 660                                         } else {
 661                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 662                                         }
 663                                 }
 664                         }
 665                         for package in claimed_outputs_material.drain(..) {
 666                                 let entry = OnchainEventEntry {
 667                                         txid: tx.txid(),
 668                                         height: conf_height,
 669                                         event: OnchainEvent::ContentiousOutpoint { package },
 670                                 };
 671                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 672                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 673                                 }
 674                         }
 675                 }
 676
 677                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 678                 let onchain_events_awaiting_threshold_conf =
 679                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
 680                 for entry in onchain_events_awaiting_threshold_conf {
 681                         if entry.has_reached_confirmation_threshold(cur_height) {
 682                                 match entry.event {
 683                                         OnchainEvent::Claim { claim_request } => {
 684                                                 // We may remove a whole set of claim outpoints here, as these one may have
 685                                                 // been aggregated in a single tx and claimed so atomically
 686                                                 if let Some(request) = self.pending_claim_requests.remove(&claim_request) {
 687                                                         for outpoint in request.outpoints() {
 688                                                                 log_debug!(logger, "Removing claim tracking for {} due to maturation of claim tx {}.", outpoint, claim_request);
 689                                                                 self.claimable_outpoints.remove(&outpoint);
 690                                                                 #[cfg(anchors)]
 691                                                                 self.pending_claim_events.remove(&claim_request);
 692                                                         }
 693                                                 }
 694                                         },
 695                                         OnchainEvent::ContentiousOutpoint { package } => {
 696                                                 log_debug!(logger, "Removing claim tracking due to maturation of claim tx for outpoints:");
 697                                                 log_debug!(logger, " {:?}", package.outpoints());
 698                                                 self.claimable_outpoints.remove(&package.outpoints()[0]);
 699                                         }
 700                                 }
 701                         } else {
 702                                 self.onchain_events_awaiting_threshold_conf.push(entry);
 703                         }
 704                 }
 705
 706                 // Check if any pending claim request must be rescheduled
 707                 for (first_claim_txid, ref request) in self.pending_claim_requests.iter() {
 708                         if let Some(h) = request.timer() {
 709                                 if cur_height >= h {
 710                                         bump_candidates.insert(*first_claim_txid, (*request).clone());
 711                                 }
 712                         }
 713                 }
 714
 715                 // Build, bump and rebroadcast tx accordingly
 716                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 717                 for (first_claim_txid, request) in bump_candidates.iter() {
 718                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(cur_height, &request, &*fee_estimator, &*logger) {
 719                                 match bump_claim {
 720                                         OnchainClaim::Tx(bump_tx) => {
 721                                                 log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx));
 722                                                 broadcaster.broadcast_transaction(&bump_tx);
 723                                         },
 724                                         #[cfg(anchors)]
 725                                         OnchainClaim::Event(claim_event) => {
 726                                                 log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
 727                                                 self.pending_claim_events.insert(*first_claim_txid, claim_event);
 728                                         },
 729                                 }
 730                                 if let Some(request) = self.pending_claim_requests.get_mut(first_claim_txid) {
 731                                         request.set_timer(new_timer);
 732                                         request.set_feerate(new_feerate);
 733                                 }
 734                         }
 735                 }
 736         }
 737
 738         pub(crate) fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
 739                 &mut self,
 740                 txid: &Txid,
 741                 broadcaster: B,
 742                 fee_estimator: &LowerBoundedFeeEstimator<F>,
 743                 logger: L,
 744         ) where
 745                 B::Target: BroadcasterInterface,
 746                 F::Target: FeeEstimator,
 747                 L::Target: Logger,
 748         {
 749                 let mut height = None;
 750                 for entry in self.onchain_events_awaiting_threshold_conf.iter() {
 751                         if entry.txid == *txid {
 752                                 height = Some(entry.height);
 753                                 break;
 754                         }
 755                 }
 756
 757                 if let Some(height) = height {
 758                         self.block_disconnected(height, broadcaster, fee_estimator, logger);
 759                 }
 760         }
 761
 762         pub(crate) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L)
 763                 where B::Target: BroadcasterInterface,
 764                       F::Target: FeeEstimator,
 765                                         L::Target: Logger,
 766         {
 767                 let mut bump_candidates = HashMap::new();
 768                 let onchain_events_awaiting_threshold_conf =
 769                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
 770                 for entry in onchain_events_awaiting_threshold_conf {
 771                         if entry.height >= height {
 772                                 //- our claim tx on a commitment tx output
 773                                 //- resurect outpoint back in its claimable set and regenerate tx
 774                                 match entry.event {
 775                                         OnchainEvent::ContentiousOutpoint { package } => {
 776                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&package.outpoints()[0]) {
 777                                                         if let Some(request) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 778                                                                 request.merge_package(package);
 779                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 780                                                                 // resurrected only one bump claim tx is going to be broadcast
 781                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), request.clone());
 782                                                         }
 783                                                 }
 784                                         },
 785                                         _ => {},
 786                                 }
 787                         } else {
 788                                 self.onchain_events_awaiting_threshold_conf.push(entry);
 789                         }
 790                 }
 791                 for (_first_claim_txid_height, request) in bump_candidates.iter_mut() {
 792                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(height, &request, fee_estimator, &&*logger) {
 793                                 request.set_timer(new_timer);
 794                                 request.set_feerate(new_feerate);
 795                                 match bump_claim {
 796                                         OnchainClaim::Tx(bump_tx) => {
 797                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx));
 798                                                 broadcaster.broadcast_transaction(&bump_tx);
 799                                         },
 800                                         #[cfg(anchors)]
 801                                         OnchainClaim::Event(claim_event) => {
 802                                                 log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
 803                                                 self.pending_claim_events.insert(_first_claim_txid_height.0, claim_event);
 804                                         },
 805                                 }
 806                         }
 807                 }
 808                 for (ancestor_claim_txid, request) in bump_candidates.drain() {
 809                         self.pending_claim_requests.insert(ancestor_claim_txid.0, request);
 810                 }
 811                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 812                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 813                 let mut remove_request = Vec::new();
 814                 self.claimable_outpoints.retain(|_, ref v|
 815                         if v.1 >= height {
 816                         remove_request.push(v.0.clone());
 817                         false
 818                         } else { true });
 819                 for req in remove_request {
 820                         self.pending_claim_requests.remove(&req);
 821                 }
 822         }
 823
 824         pub(crate) fn is_output_spend_pending(&self, outpoint: &BitcoinOutPoint) -> bool {
 825                 self.claimable_outpoints.get(outpoint).is_some()
 826         }
 827
 828         pub(crate) fn get_relevant_txids(&self) -> Vec<Txid> {
 829                 let mut txids: Vec<Txid> = self.onchain_events_awaiting_threshold_conf
 830                         .iter()
 831                         .map(|entry| entry.txid)
 832                         .collect();
 833                 txids.sort_unstable();
 834                 txids.dedup();
 835                 txids
 836         }
 837
 838         pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
 839                 self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
 840                 self.holder_htlc_sigs = None;
 841         }
 842
 843         // Normally holder HTLCs are signed at the same time as the holder commitment tx.  However,
 844         // in some configurations, the holder commitment tx has been signed and broadcast by a
 845         // ChannelMonitor replica, so we handle that case here.
 846         fn sign_latest_holder_htlcs(&mut self) {
 847                 if self.holder_htlc_sigs.is_none() {
 848                         let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
 849                         self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, sigs));
 850                 }
 851         }
 852
 853         // Normally only the latest commitment tx and HTLCs need to be signed.  However, in some
 854         // configurations we may have updated our holder commitment but a replica of the ChannelMonitor
 855         // broadcast the previous one before we sync with it.  We handle that case here.
 856         fn sign_prev_holder_htlcs(&mut self) {
 857                 if self.prev_holder_htlc_sigs.is_none() {
 858                         if let Some(ref holder_commitment) = self.prev_holder_commitment {
 859                                 let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(holder_commitment, &self.secp_ctx).expect("sign previous holder commitment");
 860                                 self.prev_holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
 861                         }
 862                 }
 863         }
 864
 865         fn extract_holder_sigs(holder_commitment: &HolderCommitmentTransaction, sigs: Vec<Signature>) -> Vec<Option<(usize, Signature)>> {
 866                 let mut ret = Vec::new();
 867                 for (htlc_idx, (holder_sig, htlc)) in sigs.iter().zip(holder_commitment.htlcs().iter()).enumerate() {
 868                         let tx_idx = htlc.transaction_output_index.unwrap();
 869                         if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 870                         ret[tx_idx as usize] = Some((htlc_idx, holder_sig.clone()));
 871                 }
 872                 ret
 873         }
 874
 875         //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
 876         // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 877         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 878         // to monitor before.
 879         pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
 880                 let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
 881                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
 882                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
 883         }
 884
 885         #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
 886         pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
 887                 let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
 888                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
 889                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
 890         }
 891
 892         pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 893                 let mut htlc_tx = None;
 894                 let commitment_txid = self.holder_commitment.trust().txid();
 895                 // Check if the HTLC spends from the current holder commitment
 896                 if commitment_txid == outp.txid {
 897                         self.sign_latest_holder_htlcs();
 898                         if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
 899                                 let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 900                                 let trusted_tx = self.holder_commitment.trust();
 901                                 let counterparty_htlc_sig = self.holder_commitment.counterparty_htlc_sigs[*htlc_idx];
 902                                 htlc_tx = Some(trusted_tx
 903                                         .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
 904                         }
 905                 }
 906                 // If the HTLC doesn't spend the current holder commitment, check if it spends the previous one
 907                 if htlc_tx.is_none() && self.prev_holder_commitment.is_some() {
 908                         let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().trust().txid();
 909                         if commitment_txid == outp.txid {
 910                                 self.sign_prev_holder_htlcs();
 911                                 if let &Some(ref htlc_sigs) = &self.prev_holder_htlc_sigs {
 912                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 913                                         let holder_commitment = self.prev_holder_commitment.as_ref().unwrap();
 914                                         let trusted_tx = holder_commitment.trust();
 915                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[*htlc_idx];
 916                                         htlc_tx = Some(trusted_tx
 917                                                 .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
 918                                 }
 919                         }
 920                 }
 921                 htlc_tx
 922         }
 923
 924         pub(crate) fn opt_anchors(&self) -> bool {
 925                 self.channel_transaction_parameters.opt_anchors.is_some()
 926         }
 927
 928         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
 929         pub(crate) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 930                 let latest_had_sigs = self.holder_htlc_sigs.is_some();
 931                 let prev_had_sigs = self.prev_holder_htlc_sigs.is_some();
 932                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
 933                 if !latest_had_sigs {
 934                         self.holder_htlc_sigs = None;
 935                 }
 936                 if !prev_had_sigs {
 937                         self.prev_holder_htlc_sigs = None;
 938                 }
 939                 ret
 940         }
 941 }