_ 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 #[cfg(anchors)]
  16 use bitcoin::PackedLockTime;
  17 use bitcoin::blockdata::transaction::Transaction;
  18 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
  19 use bitcoin::blockdata::script::Script;
  20 use bitcoin::hashes::Hash;
  21 #[cfg(anchors)]
  22 use bitcoin::hashes::HashEngine;
  23 #[cfg(anchors)]
  24 use bitcoin::hashes::sha256::Hash as Sha256;
  25 use bitcoin::hash_types::{Txid, BlockHash};
  26 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
  27 use bitcoin::secp256k1;
  28
  29 use crate::sign::{ChannelSigner, EntropySource, SignerProvider};
  30 use crate::ln::msgs::DecodeError;
  31 use crate::ln::PaymentPreimage;
  32 #[cfg(anchors)]
  33 use crate::ln::chan_utils::{self, HTLCOutputInCommitment};
  34 use crate::ln::chan_utils::{ChannelTransactionParameters, HolderCommitmentTransaction};
  35 #[cfg(anchors)]
  36 use crate::chain::chaininterface::ConfirmationTarget;
  37 use crate::chain::chaininterface::{FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator};
  38 use crate::chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER};
  39 use crate::sign::WriteableEcdsaChannelSigner;
  40 #[cfg(anchors)]
  41 use crate::chain::package::PackageSolvingData;
  42 use crate::chain::package::PackageTemplate;
  43 use crate::util::logger::Logger;
  44 use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, UpgradableRequired, Writer, Writeable, VecWriter};
  45
  46 use crate::io;
  47 use crate::prelude::*;
  48 use alloc::collections::BTreeMap;
  49 use core::cmp;
  50 use core::ops::Deref;
  51 use core::mem::replace;
  52 #[cfg(anchors)]
  53 use core::mem::swap;
  54
  55 const MAX_ALLOC_SIZE: usize = 64*1024;
  56
  57 /// An entry for an [`OnchainEvent`], stating the block height when the event was observed and the
  58 /// transaction causing it.
  59 ///
  60 /// Used to determine when the on-chain event can be considered safe from a chain reorganization.
  61 #[derive(PartialEq, Eq)]
  62 struct OnchainEventEntry {
  63         txid: Txid,
  64         height: u32,
  65         block_hash: Option<BlockHash>, // Added as optional, will be filled in for any entry generated on 0.0.113 or after
  66         event: OnchainEvent,
  67 }
  68
  69 impl OnchainEventEntry {
  70         fn confirmation_threshold(&self) -> u32 {
  71                 self.height + ANTI_REORG_DELAY - 1
  72         }
  73
  74         fn has_reached_confirmation_threshold(&self, height: u32) -> bool {
  75                 height >= self.confirmation_threshold()
  76         }
  77 }
  78
  79 /// Events for claims the [`OnchainTxHandler`] has generated. Once the events are considered safe
  80 /// from a chain reorg, the [`OnchainTxHandler`] will act accordingly.
  81 #[derive(PartialEq, Eq)]
  82 enum OnchainEvent {
  83         /// A pending request has been claimed by a transaction spending the exact same set of outpoints
  84         /// as the request. This claim can either be ours or from the counterparty. Once the claiming
  85         /// transaction has met [`ANTI_REORG_DELAY`] confirmations, we consider it final and remove the
  86         /// pending request.
  87         Claim {
  88                 package_id: PackageID,
  89         },
  90         /// The counterparty has claimed an outpoint from one of our pending requests through a
  91         /// different transaction than ours. If our transaction was attempting to claim multiple
  92         /// outputs, we need to drop the outpoint claimed by the counterparty and regenerate a new claim
  93         /// transaction for ourselves. We keep tracking, separately, the outpoint claimed by the
  94         /// counterparty up to [`ANTI_REORG_DELAY`] confirmations to ensure we attempt to re-claim it
  95         /// if the counterparty's claim is reorged from the chain.
  96         ContentiousOutpoint {
  97                 package: PackageTemplate,
  98         }
  99 }
 100
 101 impl Writeable for OnchainEventEntry {
 102         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 103                 write_tlv_fields!(writer, {
 104                         (0, self.txid, required),
 105                         (1, self.block_hash, option),
 106                         (2, self.height, required),
 107                         (4, self.event, required),
 108                 });
 109                 Ok(())
 110         }
 111 }
 112
 113 impl MaybeReadable for OnchainEventEntry {
 114         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
 115                 let mut txid = Txid::all_zeros();
 116                 let mut height = 0;
 117                 let mut block_hash = None;
 118                 let mut event = UpgradableRequired(None);
 119                 read_tlv_fields!(reader, {
 120                         (0, txid, required),
 121                         (1, block_hash, option),
 122                         (2, height, required),
 123                         (4, event, upgradable_required),
 124                 });
 125                 Ok(Some(Self { txid, height, block_hash, event: _init_tlv_based_struct_field!(event, upgradable_required) }))
 126         }
 127 }
 128
 129 impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
 130         (0, Claim) => {
 131                 (0, package_id, required),
 132         },
 133         (1, ContentiousOutpoint) => {
 134                 (0, package, required),
 135         },
 136 );
 137
 138 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 139         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 140                 match Readable::read(reader)? {
 141                         0u8 => Ok(None),
 142                         1u8 => {
 143                                 let vlen: u64 = Readable::read(reader)?;
 144                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::core::mem::size_of::<Option<(usize, Signature)>>()));
 145                                 for _ in 0..vlen {
 146                                         ret.push(match Readable::read(reader)? {
 147                                                 0u8 => None,
 148                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 149                                                 _ => return Err(DecodeError::InvalidValue)
 150                                         });
 151                                 }
 152                                 Ok(Some(ret))
 153                         },
 154                         _ => Err(DecodeError::InvalidValue),
 155                 }
 156         }
 157 }
 158
 159 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 160         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 161                 match self {
 162                         &Some(ref vec) => {
 163                                 1u8.write(writer)?;
 164                                 (vec.len() as u64).write(writer)?;
 165                                 for opt in vec.iter() {
 166                                         match opt {
 167                                                 &Some((ref idx, ref sig)) => {
 168                                                         1u8.write(writer)?;
 169                                                         (*idx as u64).write(writer)?;
 170                                                         sig.write(writer)?;
 171                                                 },
 172                                                 &None => 0u8.write(writer)?,
 173                                         }
 174                                 }
 175                         },
 176                         &None => 0u8.write(writer)?,
 177                 }
 178                 Ok(())
 179         }
 180 }
 181
 182 #[cfg(anchors)]
 183 /// The claim commonly referred to as the pre-signed second-stage HTLC transaction.
 184 pub(crate) struct ExternalHTLCClaim {
 185         pub(crate) commitment_txid: Txid,
 186         pub(crate) per_commitment_number: u64,
 187         pub(crate) htlc: HTLCOutputInCommitment,
 188         pub(crate) preimage: Option<PaymentPreimage>,
 189         pub(crate) counterparty_sig: Signature,
 190 }
 191
 192 // Represents the different types of claims for which events are yielded externally to satisfy said
 193 // claims.
 194 #[cfg(anchors)]
 195 pub(crate) enum ClaimEvent {
 196         /// Event yielded to signal that the commitment transaction fee must be bumped to claim any
 197         /// encumbered funds and proceed to HTLC resolution, if any HTLCs exist.
 198         BumpCommitment {
 199                 package_target_feerate_sat_per_1000_weight: u32,
 200                 commitment_tx: Transaction,
 201                 anchor_output_idx: u32,
 202         },
 203         /// Event yielded to signal that the commitment transaction has confirmed and its HTLCs must be
 204         /// resolved by broadcasting a transaction with sufficient fee to claim them.
 205         BumpHTLC {
 206                 target_feerate_sat_per_1000_weight: u32,
 207                 htlcs: Vec<ExternalHTLCClaim>,
 208                 tx_lock_time: PackedLockTime,
 209         },
 210 }
 211
 212 /// Represents the different ways an output can be claimed (i.e., spent to an address under our
 213 /// control) onchain.
 214 pub(crate) enum OnchainClaim {
 215         /// A finalized transaction pending confirmation spending the output to claim.
 216         Tx(Transaction),
 217         #[cfg(anchors)]
 218         /// An event yielded externally to signal additional inputs must be added to a transaction
 219         /// pending confirmation spending the output to claim.
 220         Event(ClaimEvent),
 221 }
 222
 223 /// An internal identifier to track pending package claims within the `OnchainTxHandler`.
 224 type PackageID = [u8; 32];
 225
 226 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 227 /// do RBF bumping if possible.
 228 pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
 229         destination_script: Script,
 230         holder_commitment: HolderCommitmentTransaction,
 231         // holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
 232         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 233         // the set of HTLCs in the HolderCommitmentTransaction.
 234         holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 235         prev_holder_commitment: Option<HolderCommitmentTransaction>,
 236         prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 237
 238         pub(super) signer: ChannelSigner,
 239         pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 240
 241         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 242         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 243         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 244         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 245         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 246         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 247         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 248         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 249         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 250         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 251         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 252         #[cfg(test)] // Used in functional_test to verify sanitization
 253         pub(crate) pending_claim_requests: HashMap<PackageID, PackageTemplate>,
 254         #[cfg(not(test))]
 255         pending_claim_requests: HashMap<PackageID, PackageTemplate>,
 256
 257         // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
 258         // essentially acts as an insertion-ordered `HashMap` – there should only ever be one occurrence
 259         // of a `PackageID`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
 260         // a new block has been connected, resulting in a new claim, the previous will be replaced with
 261         // the new.
 262         //
 263         // These external events may be generated in the following cases:
 264         //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
 265         //      - A block being connected/disconnected
 266         //      - Learning the preimage for an HTLC we can claim onchain
 267         #[cfg(anchors)]
 268         pending_claim_events: Vec<(PackageID, ClaimEvent)>,
 269
 270         // Used to link outpoints claimed in a connected block to a pending claim request. The keys
 271         // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
 272         // claim. The values track the pending claim request identifier and the initial confirmation
 273         // block height, and are immutable until the outpoint has enough confirmations to meet our
 274         // [`ANTI_REORG_DELAY`]. The initial confirmation block height is used to remove the entry if
 275         // the block gets disconnected.
 276         #[cfg(test)] // Used in functional_test to verify sanitization
 277         pub claimable_outpoints: HashMap<BitcoinOutPoint, (PackageID, u32)>,
 278         #[cfg(not(test))]
 279         claimable_outpoints: HashMap<BitcoinOutPoint, (PackageID, u32)>,
 280
 281         locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
 282
 283         onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
 284
 285         pub(super) secp_ctx: Secp256k1<secp256k1::All>,
 286 }
 287
 288 impl<ChannelSigner: WriteableEcdsaChannelSigner> PartialEq for OnchainTxHandler<ChannelSigner> {
 289         fn eq(&self, other: &Self) -> bool {
 290                 // `signer`, `secp_ctx`, and `pending_claim_events` are excluded on purpose.
 291                 self.destination_script == other.destination_script &&
 292                         self.holder_commitment == other.holder_commitment &&
 293                         self.holder_htlc_sigs == other.holder_htlc_sigs &&
 294                         self.prev_holder_commitment == other.prev_holder_commitment &&
 295                         self.prev_holder_htlc_sigs == other.prev_holder_htlc_sigs &&
 296                         self.channel_transaction_parameters == other.channel_transaction_parameters &&
 297                         self.pending_claim_requests == other.pending_claim_requests &&
 298                         self.claimable_outpoints == other.claimable_outpoints &&
 299                         self.locktimed_packages == other.locktimed_packages &&
 300                         self.onchain_events_awaiting_threshold_conf == other.onchain_events_awaiting_threshold_conf
 301         }
 302 }
 303
 304 const SERIALIZATION_VERSION: u8 = 1;
 305 const MIN_SERIALIZATION_VERSION: u8 = 1;
 306
 307 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 308         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 309                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 310
 311                 self.destination_script.write(writer)?;
 312                 self.holder_commitment.write(writer)?;
 313                 self.holder_htlc_sigs.write(writer)?;
 314                 self.prev_holder_commitment.write(writer)?;
 315                 self.prev_holder_htlc_sigs.write(writer)?;
 316
 317                 self.channel_transaction_parameters.write(writer)?;
 318
 319                 let mut key_data = VecWriter(Vec::new());
 320                 self.signer.write(&mut key_data)?;
 321                 assert!(key_data.0.len() < core::usize::MAX);
 322                 assert!(key_data.0.len() < core::u32::MAX as usize);
 323                 (key_data.0.len() as u32).write(writer)?;
 324                 writer.write_all(&key_data.0[..])?;
 325
 326                 writer.write_all(&(self.pending_claim_requests.len() as u64).to_be_bytes())?;
 327                 for (ref ancestor_claim_txid, request) in self.pending_claim_requests.iter() {
 328                         ancestor_claim_txid.write(writer)?;
 329                         request.write(writer)?;
 330                 }
 331
 332                 writer.write_all(&(self.claimable_outpoints.len() as u64).to_be_bytes())?;
 333                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 334                         outp.write(writer)?;
 335                         claim_and_height.0.write(writer)?;
 336                         claim_and_height.1.write(writer)?;
 337                 }
 338
 339                 writer.write_all(&(self.locktimed_packages.len() as u64).to_be_bytes())?;
 340                 for (ref locktime, ref packages) in self.locktimed_packages.iter() {
 341                         locktime.write(writer)?;
 342                         writer.write_all(&(packages.len() as u64).to_be_bytes())?;
 343                         for ref package in packages.iter() {
 344                                 package.write(writer)?;
 345                         }
 346                 }
 347
 348                 writer.write_all(&(self.onchain_events_awaiting_threshold_conf.len() as u64).to_be_bytes())?;
 349                 for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
 350                         entry.write(writer)?;
 351                 }
 352
 353                 write_tlv_fields!(writer, {});
 354                 Ok(())
 355         }
 356 }
 357
 358 impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::Signer> {
 359         fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP, u64, [u8; 32])) -> Result<Self, DecodeError> {
 360                 let entropy_source = args.0;
 361                 let signer_provider = args.1;
 362                 let channel_value_satoshis = args.2;
 363                 let channel_keys_id = args.3;
 364
 365                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 366
 367                 let destination_script = Readable::read(reader)?;
 368
 369                 let holder_commitment = Readable::read(reader)?;
 370                 let holder_htlc_sigs = Readable::read(reader)?;
 371                 let prev_holder_commitment = Readable::read(reader)?;
 372                 let prev_holder_htlc_sigs = Readable::read(reader)?;
 373
 374                 let channel_parameters = Readable::read(reader)?;
 375
 376                 // Read the serialized signer bytes, but don't deserialize them, as we'll obtain our signer
 377                 // by re-deriving the private key material.
 378                 let keys_len: u32 = Readable::read(reader)?;
 379                 let mut bytes_read = 0;
 380                 while bytes_read != keys_len as usize {
 381                         // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
 382                         let mut data = [0; 1024];
 383                         let bytes_to_read = cmp::min(1024, keys_len as usize - bytes_read);
 384                         let read_slice = &mut data[0..bytes_to_read];
 385                         reader.read_exact(read_slice)?;
 386                         bytes_read += bytes_to_read;
 387                 }
 388
 389                 let mut signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
 390                 signer.provide_channel_parameters(&channel_parameters);
 391
 392                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 393                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 394                 for _ in 0..pending_claim_requests_len {
 395                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 396                 }
 397
 398                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 399                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 400                 for _ in 0..claimable_outpoints_len {
 401                         let outpoint = Readable::read(reader)?;
 402                         let ancestor_claim_txid = Readable::read(reader)?;
 403                         let height = Readable::read(reader)?;
 404                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 405                 }
 406
 407                 let locktimed_packages_len: u64 = Readable::read(reader)?;
 408                 let mut locktimed_packages = BTreeMap::new();
 409                 for _ in 0..locktimed_packages_len {
 410                         let locktime = Readable::read(reader)?;
 411                         let packages_len: u64 = Readable::read(reader)?;
 412                         let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
 413                         for _ in 0..packages_len {
 414                                 packages.push(Readable::read(reader)?);
 415                         }
 416                         locktimed_packages.insert(locktime, packages);
 417                 }
 418
 419                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 420                 let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 421                 for _ in 0..waiting_threshold_conf_len {
 422                         if let Some(val) = MaybeReadable::read(reader)? {
 423                                 onchain_events_awaiting_threshold_conf.push(val);
 424                         }
 425                 }
 426
 427                 read_tlv_fields!(reader, {});
 428
 429                 let mut secp_ctx = Secp256k1::new();
 430                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 431
 432                 Ok(OnchainTxHandler {
 433                         destination_script,
 434                         holder_commitment,
 435                         holder_htlc_sigs,
 436                         prev_holder_commitment,
 437                         prev_holder_htlc_sigs,
 438                         signer,
 439                         channel_transaction_parameters: channel_parameters,
 440                         claimable_outpoints,
 441                         locktimed_packages,
 442                         pending_claim_requests,
 443                         onchain_events_awaiting_threshold_conf,
 444                         #[cfg(anchors)]
 445                         pending_claim_events: Vec::new(),
 446                         secp_ctx,
 447                 })
 448         }
 449 }
 450
 451 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 452         pub(crate) fn new(destination_script: Script, signer: ChannelSigner, channel_parameters: ChannelTransactionParameters, holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>) -> Self {
 453                 OnchainTxHandler {
 454                         destination_script,
 455                         holder_commitment,
 456                         holder_htlc_sigs: None,
 457                         prev_holder_commitment: None,
 458                         prev_holder_htlc_sigs: None,
 459                         signer,
 460                         channel_transaction_parameters: channel_parameters,
 461                         pending_claim_requests: HashMap::new(),
 462                         claimable_outpoints: HashMap::new(),
 463                         locktimed_packages: BTreeMap::new(),
 464                         onchain_events_awaiting_threshold_conf: Vec::new(),
 465                         #[cfg(anchors)]
 466                         pending_claim_events: Vec::new(),
 467                         secp_ctx,
 468                 }
 469         }
 470
 471         pub(crate) fn get_prev_holder_commitment_to_self_value(&self) -> Option<u64> {
 472                 self.prev_holder_commitment.as_ref().map(|commitment| commitment.to_broadcaster_value_sat())
 473         }
 474
 475         pub(crate) fn get_cur_holder_commitment_to_self_value(&self) -> u64 {
 476                 self.holder_commitment.to_broadcaster_value_sat()
 477         }
 478
 479         #[cfg(anchors)]
 480         pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<ClaimEvent> {
 481                 let mut events = Vec::new();
 482                 swap(&mut events, &mut self.pending_claim_events);
 483                 events.into_iter().map(|(_, event)| event).collect()
 484         }
 485
 486         /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
 487         /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
 488         /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
 489         /// invoking this every 30 seconds, or lower if running in an environment with spotty
 490         /// connections, like on mobile.
 491         pub(crate) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Deref>(
 492                 &mut self, current_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>,
 493                 logger: &L,
 494         )
 495         where
 496                 B::Target: BroadcasterInterface,
 497                 F::Target: FeeEstimator,
 498                 L::Target: Logger,
 499         {
 500                 let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
 501                 for (package_id, request) in self.pending_claim_requests.iter() {
 502                         let inputs = request.outpoints();
 503                         log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
 504                         bump_requests.push((*package_id, request.clone()));
 505                 }
 506                 for (package_id, request) in bump_requests {
 507                         self.generate_claim(current_height, &request, false /* force_feerate_bump */, fee_estimator, logger)
 508                                 .map(|(_, new_feerate, claim)| {
 509                                         let mut bumped_feerate = false;
 510                                         if let Some(mut_request) = self.pending_claim_requests.get_mut(&package_id) {
 511                                                 bumped_feerate = request.previous_feerate() > new_feerate;
 512                                                 mut_request.set_feerate(new_feerate);
 513                                         }
 514                                         match claim {
 515                                                 OnchainClaim::Tx(tx) => {
 516                                                         let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
 517                                                         log_info!(logger, "{} onchain {}", log_start, log_tx!(tx));
 518                                                         broadcaster.broadcast_transactions(&[&tx]);
 519                                                 },
 520                                                 #[cfg(anchors)]
 521                                                 OnchainClaim::Event(event) => {
 522                                                         let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" };
 523                                                         log_info!(logger, "{} onchain event to spend inputs {:?}", log_start,
 524                                                                 request.outpoints());
 525                                                         #[cfg(debug_assertions)] {
 526                                                                 debug_assert!(request.requires_external_funding());
 527                                                                 let num_existing = self.pending_claim_events.iter()
 528                                                                         .filter(|entry| entry.0 == package_id).count();
 529                                                                 assert!(num_existing == 0 || num_existing == 1);
 530                                                         }
 531                                                         self.pending_claim_events.retain(|event| event.0 != package_id);
 532                                                         self.pending_claim_events.push((package_id, event));
 533                                                 }
 534                                         }
 535                                 });
 536                 }
 537         }
 538
 539         /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
 540         /// onchain) lays on the assumption of claim transactions getting confirmed before timelock
 541         /// expiration (CSV or CLTV following cases). In case of high-fee spikes, claim tx may get stuck
 542         /// in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or
 543         /// Child-Pay-For-Parent.
 544         ///
 545         /// Panics if there are signing errors, because signing operations in reaction to on-chain
 546         /// events are not expected to fail, and if they do, we may lose funds.
 547         fn generate_claim<F: Deref, L: Deref>(
 548                 &mut self, cur_height: u32, cached_request: &PackageTemplate, force_feerate_bump: bool,
 549                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 550         ) -> Option<(u32, u64, OnchainClaim)>
 551         where
 552                 F::Target: FeeEstimator,
 553                 L::Target: Logger,
 554         {
 555                 let request_outpoints = cached_request.outpoints();
 556                 if request_outpoints.is_empty() {
 557                         // Don't prune pending claiming request yet, we may have to resurrect HTLCs. Untractable
 558                         // packages cannot be aggregated and will never be split, so we cannot end up with an
 559                         // empty claim.
 560                         debug_assert!(cached_request.is_malleable());
 561                         return None;
 562                 }
 563                 // If we've seen transaction inclusion in the chain for all outpoints in our request, we
 564                 // don't need to continue generating more claims. We'll keep tracking the request to fully
 565                 // remove it once it reaches the confirmation threshold, or to generate a new claim if the
 566                 // transaction is reorged out.
 567                 let mut all_inputs_have_confirmed_spend = true;
 568                 for outpoint in request_outpoints.iter() {
 569                         if let Some((request_package_id, _)) = self.claimable_outpoints.get(*outpoint) {
 570                                 // We check for outpoint spends within claims individually rather than as a set
 571                                 // since requests can have outpoints split off.
 572                                 if !self.onchain_events_awaiting_threshold_conf.iter()
 573                                         .any(|event_entry| if let OnchainEvent::Claim { package_id } = event_entry.event {
 574                                                 *request_package_id == package_id
 575                                         } else {
 576                                                 // The onchain event is not a claim, keep seeking until we find one.
 577                                                 false
 578                                         })
 579                                 {
 580                                         // Either we had no `OnchainEvent::Claim`, or we did but none matched the
 581                                         // outpoint's registered spend.
 582                                         all_inputs_have_confirmed_spend = false;
 583                                 }
 584                         } else {
 585                                 // The request's outpoint spend does not exist yet.
 586                                 all_inputs_have_confirmed_spend = false;
 587                         }
 588                 }
 589                 if all_inputs_have_confirmed_spend {
 590                         return None;
 591                 }
 592
 593                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 594                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 595                 let new_timer = cached_request.get_height_timer(cur_height);
 596                 if cached_request.is_malleable() {
 597                         #[cfg(anchors)]
 598                         { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
 599                                 if cached_request.requires_external_funding() {
 600                                         let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
 601                                                 fee_estimator, ConfirmationTarget::HighPriority, force_feerate_bump
 602                                         );
 603                                         if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
 604                                                 return Some((
 605                                                         new_timer,
 606                                                         target_feerate_sat_per_1000_weight as u64,
 607                                                         OnchainClaim::Event(ClaimEvent::BumpHTLC {
 608                                                                 target_feerate_sat_per_1000_weight,
 609                                                                 htlcs,
 610                                                                 tx_lock_time: PackedLockTime(cached_request.package_locktime(cur_height)),
 611                                                         }),
 612                                                 ));
 613                                         } else {
 614                                                 return None;
 615                                         }
 616                                 }
 617                         }
 618
 619                         let predicted_weight = cached_request.package_weight(&self.destination_script);
 620                         if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
 621                                 predicted_weight, self.destination_script.dust_value().to_sat(),
 622                                 force_feerate_bump, fee_estimator, logger,
 623                         ) {
 624                                 assert!(new_feerate != 0);
 625
 626                                 let transaction = cached_request.finalize_malleable_package(
 627                                         cur_height, self, output_value, self.destination_script.clone(), logger
 628                                 ).unwrap();
 629                                 log_trace!(logger, "...with timer {} and feerate {}", new_timer, new_feerate);
 630                                 assert!(predicted_weight >= transaction.weight());
 631                                 return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
 632                         }
 633                 } else {
 634                         // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
 635                         // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
 636                         // which require external funding.
 637                         #[cfg(not(anchors))]
 638                         let inputs = cached_request.inputs();
 639                         #[cfg(anchors)]
 640                         let mut inputs = cached_request.inputs();
 641                         debug_assert_eq!(inputs.len(), 1);
 642                         let tx = match cached_request.finalize_untractable_package(self, logger) {
 643                                 Some(tx) => tx,
 644                                 None => return None,
 645                         };
 646                         if !cached_request.requires_external_funding() {
 647                                 return Some((new_timer, 0, OnchainClaim::Tx(tx)));
 648                         }
 649                         #[cfg(anchors)]
 650                         return inputs.find_map(|input| match input {
 651                                 // Commitment inputs with anchors support are the only untractable inputs supported
 652                                 // thus far that require external funding.
 653                                 PackageSolvingData::HolderFundingOutput(..) => {
 654                                         debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(),
 655                                                 "Holder commitment transaction mismatch");
 656                                         // We'll locate an anchor output we can spend within the commitment transaction.
 657                                         let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
 658                                         match chan_utils::get_anchor_output(&tx, funding_pubkey) {
 659                                                 // An anchor output was found, so we should yield a funding event externally.
 660                                                 Some((idx, _)) => {
 661                                                         // TODO: Use a lower confirmation target when both our and the
 662                                                         // counterparty's latest commitment don't have any HTLCs present.
 663                                                         let conf_target = ConfirmationTarget::HighPriority;
 664                                                         let package_target_feerate_sat_per_1000_weight = cached_request
 665                                                                 .compute_package_feerate(fee_estimator, conf_target, force_feerate_bump);
 666                                                         Some((
 667                                                                 new_timer,
 668                                                                 package_target_feerate_sat_per_1000_weight as u64,
 669                                                                 OnchainClaim::Event(ClaimEvent::BumpCommitment {
 670                                                                         package_target_feerate_sat_per_1000_weight,
 671                                                                         commitment_tx: tx.clone(),
 672                                                                         anchor_output_idx: idx,
 673                                                                 }),
 674                                                         ))
 675                                                 },
 676                                                 // An anchor output was not found. There's nothing we can do other than
 677                                                 // attempt to broadcast the transaction with its current fee rate and hope
 678                                                 // it confirms. This is essentially the same behavior as a commitment
 679                                                 // transaction without anchor outputs.
 680                                                 None => Some((new_timer, 0, OnchainClaim::Tx(tx.clone()))),
 681                                         }
 682                                 },
 683                                 _ => {
 684                                         debug_assert!(false, "Only HolderFundingOutput inputs should be untractable and require external funding");
 685                                         None
 686                                 },
 687                         })
 688                 }
 689                 None
 690         }
 691
 692         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 693         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 694         /// Together with `update_claims_view_from_matched_txn` this used to be named
 695         /// `block_connected`, but it is now also used for claiming an HTLC output if we receive a
 696         /// preimage after force-close.
 697         ///
 698         /// `conf_height` represents the height at which the request was generated. This
 699         /// does not need to equal the current blockchain tip height, which should be provided via
 700         /// `cur_height`, however it must never be higher than `cur_height`.
 701         pub(crate) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Deref>(
 702                 &mut self, requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32,
 703                 broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 704         ) where
 705                 B::Target: BroadcasterInterface,
 706                 F::Target: FeeEstimator,
 707                 L::Target: Logger,
 708         {
 709                 log_debug!(logger, "Updating claims view at height {} with {} claim requests", cur_height, requests.len());
 710                 let mut preprocessed_requests = Vec::with_capacity(requests.len());
 711                 let mut aggregated_request = None;
 712
 713                 // Try to aggregate outputs if their timelock expiration isn't imminent (package timelock
 714                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 715                 for req in requests {
 716                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 717                         if let Some(_) = self.claimable_outpoints.get(req.outpoints()[0]) {
 718                                 log_info!(logger, "Ignoring second claim for outpoint {}:{}, already registered its claiming request", req.outpoints()[0].txid, req.outpoints()[0].vout);
 719                         } else {
 720                                 let timelocked_equivalent_package = self.locktimed_packages.iter().map(|v| v.1.iter()).flatten()
 721                                         .find(|locked_package| locked_package.outpoints() == req.outpoints());
 722                                 if let Some(package) = timelocked_equivalent_package {
 723                                         log_info!(logger, "Ignoring second claim for outpoint {}:{}, we already have one which we're waiting on a timelock at {} for.",
 724                                                 req.outpoints()[0].txid, req.outpoints()[0].vout, package.package_locktime(cur_height));
 725                                         continue;
 726                                 }
 727
 728                                 let package_locktime = req.package_locktime(cur_height);
 729                                 if package_locktime > cur_height + 1 {
 730                                         log_info!(logger, "Delaying claim of package until its timelock at {} (current height {}), the following outpoints are spent:", package_locktime, cur_height);
 731                                         for outpoint in req.outpoints() {
 732                                                 log_info!(logger, "  Outpoint {}", outpoint);
 733                                         }
 734                                         self.locktimed_packages.entry(package_locktime).or_insert(Vec::new()).push(req);
 735                                         continue;
 736                                 }
 737
 738                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.timelock(), cur_height + CLTV_SHARED_CLAIM_BUFFER);
 739                                 if req.timelock() <= cur_height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable() {
 740                                         // Don't aggregate if outpoint package timelock is soon or marked as non-aggregable
 741                                         preprocessed_requests.push(req);
 742                                 } else if aggregated_request.is_none() {
 743                                         aggregated_request = Some(req);
 744                                 } else {
 745                                         aggregated_request.as_mut().unwrap().merge_package(req);
 746                                 }
 747                         }
 748                 }
 749                 if let Some(req) = aggregated_request {
 750                         preprocessed_requests.push(req);
 751                 }
 752
 753                 // Claim everything up to and including `cur_height`
 754                 let remaining_locked_packages = self.locktimed_packages.split_off(&(cur_height + 1));
 755                 for (pop_height, mut entry) in self.locktimed_packages.iter_mut() {
 756                         log_trace!(logger, "Restoring delayed claim of package(s) at their timelock at {}.", pop_height);
 757                         preprocessed_requests.append(&mut entry);
 758                 }
 759                 self.locktimed_packages = remaining_locked_packages;
 760
 761                 // Generate claim transactions and track them to bump if necessary at
 762                 // height timer expiration (i.e in how many blocks we're going to take action).
 763                 for mut req in preprocessed_requests {
 764                         if let Some((new_timer, new_feerate, claim)) = self.generate_claim(
 765                                 cur_height, &req, true /* force_feerate_bump */, &*fee_estimator, &*logger,
 766                         ) {
 767                                 req.set_timer(new_timer);
 768                                 req.set_feerate(new_feerate);
 769                                 let package_id = match claim {
 770                                         OnchainClaim::Tx(tx) => {
 771                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(tx));
 772                                                 broadcaster.broadcast_transactions(&[&tx]);
 773                                                 tx.txid().into_inner()
 774                                         },
 775                                         #[cfg(anchors)]
 776                                         OnchainClaim::Event(claim_event) => {
 777                                                 log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
 778                                                 let package_id = match claim_event {
 779                                                         ClaimEvent::BumpCommitment { ref commitment_tx, .. } =>
 780                                                                 // For commitment claims, we can just use their txid as it should
 781                                                                 // already be unique.
 782                                                                 commitment_tx.txid().into_inner(),
 783                                                         ClaimEvent::BumpHTLC { ref htlcs, .. } => {
 784                                                                 // For HTLC claims, commit to the entire set of HTLC outputs to
 785                                                                 // claim, which will always be unique per request. Once a claim ID
 786                                                                 // is generated, it is assigned and remains unchanged, even if the
 787                                                                 // underlying set of HTLCs changes.
 788                                                                 let mut engine = Sha256::engine();
 789                                                                 for htlc in htlcs {
 790                                                                         engine.input(&htlc.commitment_txid.into_inner());
 791                                                                         engine.input(&htlc.htlc.transaction_output_index.unwrap().to_be_bytes());
 792                                                                 }
 793                                                                 Sha256::from_engine(engine).into_inner()
 794                                                         },
 795                                                 };
 796                                                 debug_assert!(self.pending_claim_requests.get(&package_id).is_none());
 797                                                 debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == package_id).count(), 0);
 798                                                 self.pending_claim_events.push((package_id, claim_event));
 799                                                 package_id
 800                                         },
 801                                 };
 802                                 for k in req.outpoints() {
 803                                         log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 804                                         self.claimable_outpoints.insert(k.clone(), (package_id, conf_height));
 805                                 }
 806                                 self.pending_claim_requests.insert(package_id, req);
 807                         }
 808                 }
 809         }
 810
 811         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 812         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 813         /// Together with `update_claims_view_from_requests` this used to be named `block_connected`,
 814         /// but it is now also used for claiming an HTLC output if we receive a preimage after force-close.
 815         ///
 816         /// `conf_height` represents the height at which the transactions in `txn_matched` were
 817         /// confirmed. This does not need to equal the current blockchain tip height, which should be
 818         /// provided via `cur_height`, however it must never be higher than `cur_height`.
 819         pub(crate) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Deref>(
 820                 &mut self, txn_matched: &[&Transaction], conf_height: u32, conf_hash: BlockHash,
 821                 cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 822         ) where
 823                 B::Target: BroadcasterInterface,
 824                 F::Target: FeeEstimator,
 825                 L::Target: Logger,
 826         {
 827                 log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {}", cur_height, txn_matched.len(), conf_height);
 828                 let mut bump_candidates = HashMap::new();
 829                 for tx in txn_matched {
 830                         // Scan all input to verify is one of the outpoint spent is of interest for us
 831                         let mut claimed_outputs_material = Vec::new();
 832                         for inp in &tx.input {
 833                                 if let Some((package_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
 834                                         // If outpoint has claim request pending on it...
 835                                         if let Some(request) = self.pending_claim_requests.get_mut(package_id) {
 836                                                 //... we need to verify equality between transaction outpoints and claim request
 837                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 838                                                 // by us.
 839                                                 let mut are_sets_equal = true;
 840                                                 let mut tx_inputs = tx.input.iter().map(|input| &input.previous_output).collect::<Vec<_>>();
 841                                                 tx_inputs.sort_unstable();
 842                                                 for request_input in request.outpoints() {
 843                                                         if tx_inputs.binary_search(&request_input).is_err() {
 844                                                                 are_sets_equal = false;
 845                                                                 break;
 846                                                         }
 847                                                 }
 848
 849                                                 macro_rules! clean_claim_request_after_safety_delay {
 850                                                         () => {
 851                                                                 let entry = OnchainEventEntry {
 852                                                                         txid: tx.txid(),
 853                                                                         height: conf_height,
 854                                                                         block_hash: Some(conf_hash),
 855                                                                         event: OnchainEvent::Claim { package_id: *package_id }
 856                                                                 };
 857                                                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 858                                                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 859                                                                 }
 860                                                         }
 861                                                 }
 862
 863                                                 // If this is our transaction (or our counterparty spent all the outputs
 864                                                 // before we could anyway with same inputs order than us), wait for
 865                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 866                                                 if are_sets_equal {
 867                                                         clean_claim_request_after_safety_delay!();
 868                                                 } else { // If false, generate new claim request with update outpoint set
 869                                                         let mut at_least_one_drop = false;
 870                                                         for input in tx.input.iter() {
 871                                                                 if let Some(package) = request.split_package(&input.previous_output) {
 872                                                                         claimed_outputs_material.push(package);
 873                                                                         at_least_one_drop = true;
 874                                                                 }
 875                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 876                                                                 if request.outpoints().is_empty() {
 877                                                                         clean_claim_request_after_safety_delay!();
 878                                                                 }
 879                                                         }
 880                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 881                                                         if at_least_one_drop {
 882                                                                 bump_candidates.insert(*package_id, request.clone());
 883                                                                 // If we have any pending claim events for the request being updated
 884                                                                 // that have yet to be consumed, we'll remove them since they will
 885                                                                 // end up producing an invalid transaction by double spending
 886                                                                 // input(s) that already have a confirmed spend. If such spend is
 887                                                                 // reorged out of the chain, then we'll attempt to re-spend the
 888                                                                 // inputs once we see it.
 889                                                                 #[cfg(anchors)] {
 890                                                                         #[cfg(debug_assertions)] {
 891                                                                                 let existing = self.pending_claim_events.iter()
 892                                                                                         .filter(|entry| entry.0 == *package_id).count();
 893                                                                                 assert!(existing == 0 || existing == 1);
 894                                                                         }
 895                                                                         self.pending_claim_events.retain(|entry| entry.0 != *package_id);
 896                                                                 }
 897                                                         }
 898                                                 }
 899                                                 break; //No need to iterate further, either tx is our or their
 900                                         } else {
 901                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 902                                         }
 903                                 }
 904                         }
 905                         for package in claimed_outputs_material.drain(..) {
 906                                 let entry = OnchainEventEntry {
 907                                         txid: tx.txid(),
 908                                         height: conf_height,
 909                                         block_hash: Some(conf_hash),
 910                                         event: OnchainEvent::ContentiousOutpoint { package },
 911                                 };
 912                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 913                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 914                                 }
 915                         }
 916                 }
 917
 918                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 919                 let onchain_events_awaiting_threshold_conf =
 920                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
 921                 for entry in onchain_events_awaiting_threshold_conf {
 922                         if entry.has_reached_confirmation_threshold(cur_height) {
 923                                 match entry.event {
 924                                         OnchainEvent::Claim { package_id } => {
 925                                                 // We may remove a whole set of claim outpoints here, as these one may have
 926                                                 // been aggregated in a single tx and claimed so atomically
 927                                                 if let Some(request) = self.pending_claim_requests.remove(&package_id) {
 928                                                         for outpoint in request.outpoints() {
 929                                                                 log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
 930                                                                         outpoint, log_bytes!(package_id));
 931                                                                 self.claimable_outpoints.remove(outpoint);
 932                                                         }
 933                                                         #[cfg(anchors)] {
 934                                                                 #[cfg(debug_assertions)] {
 935                                                                         let num_existing = self.pending_claim_events.iter()
 936                                                                                 .filter(|entry| entry.0 == package_id).count();
 937                                                                         assert!(num_existing == 0 || num_existing == 1);
 938                                                                 }
 939                                                                 self.pending_claim_events.retain(|(id, _)| *id != package_id);
 940                                                         }
 941                                                 }
 942                                         },
 943                                         OnchainEvent::ContentiousOutpoint { package } => {
 944                                                 log_debug!(logger, "Removing claim tracking due to maturation of claim tx for outpoints:");
 945                                                 log_debug!(logger, " {:?}", package.outpoints());
 946                                                 self.claimable_outpoints.remove(package.outpoints()[0]);
 947                                         }
 948                                 }
 949                         } else {
 950                                 self.onchain_events_awaiting_threshold_conf.push(entry);
 951                         }
 952                 }
 953
 954                 // Check if any pending claim request must be rescheduled
 955                 for (package_id, request) in self.pending_claim_requests.iter() {
 956                         if cur_height >= request.timer() {
 957                                 bump_candidates.insert(*package_id, request.clone());
 958                         }
 959                 }
 960
 961                 // Build, bump and rebroadcast tx accordingly
 962                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 963                 for (package_id, request) in bump_candidates.iter() {
 964                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
 965                                 cur_height, &request, true /* force_feerate_bump */, &*fee_estimator, &*logger,
 966                         ) {
 967                                 match bump_claim {
 968                                         OnchainClaim::Tx(bump_tx) => {
 969                                                 log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx));
 970                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
 971                                         },
 972                                         #[cfg(anchors)]
 973                                         OnchainClaim::Event(claim_event) => {
 974                                                 log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
 975                                                 #[cfg(debug_assertions)] {
 976                                                         let num_existing = self.pending_claim_events.iter().
 977                                                                 filter(|entry| entry.0 == *package_id).count();
 978                                                         assert!(num_existing == 0 || num_existing == 1);
 979                                                 }
 980                                                 self.pending_claim_events.retain(|event| event.0 != *package_id);
 981                                                 self.pending_claim_events.push((*package_id, claim_event));
 982                                         },
 983                                 }
 984                                 if let Some(request) = self.pending_claim_requests.get_mut(package_id) {
 985                                         request.set_timer(new_timer);
 986                                         request.set_feerate(new_feerate);
 987                                 }
 988                         }
 989                 }
 990         }
 991
 992         pub(crate) fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
 993                 &mut self,
 994                 txid: &Txid,
 995                 broadcaster: B,
 996                 fee_estimator: &LowerBoundedFeeEstimator<F>,
 997                 logger: L,
 998         ) where
 999                 B::Target: BroadcasterInterface,
1000                 F::Target: FeeEstimator,
1001                 L::Target: Logger,
1002         {
1003                 let mut height = None;
1004                 for entry in self.onchain_events_awaiting_threshold_conf.iter() {
1005                         if entry.txid == *txid {
1006                                 height = Some(entry.height);
1007                                 break;
1008                         }
1009                 }
1010
1011                 if let Some(height) = height {
1012                         self.block_disconnected(height, broadcaster, fee_estimator, logger);
1013                 }
1014         }
1015
1016         pub(crate) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L)
1017                 where B::Target: BroadcasterInterface,
1018                       F::Target: FeeEstimator,
1019                                         L::Target: Logger,
1020         {
1021                 let mut bump_candidates = HashMap::new();
1022                 let onchain_events_awaiting_threshold_conf =
1023                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
1024                 for entry in onchain_events_awaiting_threshold_conf {
1025                         if entry.height >= height {
1026                                 //- our claim tx on a commitment tx output
1027                                 //- resurect outpoint back in its claimable set and regenerate tx
1028                                 match entry.event {
1029                                         OnchainEvent::ContentiousOutpoint { package } => {
1030                                                 if let Some(pending_claim) = self.claimable_outpoints.get(package.outpoints()[0]) {
1031                                                         if let Some(request) = self.pending_claim_requests.get_mut(&pending_claim.0) {
1032                                                                 request.merge_package(package);
1033                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
1034                                                                 // resurrected only one bump claim tx is going to be broadcast
1035                                                                 bump_candidates.insert(pending_claim.clone(), request.clone());
1036                                                         }
1037                                                 }
1038                                         },
1039                                         _ => {},
1040                                 }
1041                         } else {
1042                                 self.onchain_events_awaiting_threshold_conf.push(entry);
1043                         }
1044                 }
1045                 for ((_package_id, _), ref mut request) in bump_candidates.iter_mut() {
1046                         // `height` is the height being disconnected, so our `current_height` is 1 lower.
1047                         let current_height = height - 1;
1048                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
1049                                 current_height, &request, true /* force_feerate_bump */, fee_estimator, &&*logger
1050                         ) {
1051                                 request.set_timer(new_timer);
1052                                 request.set_feerate(new_feerate);
1053                                 match bump_claim {
1054                                         OnchainClaim::Tx(bump_tx) => {
1055                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx));
1056                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
1057                                         },
1058                                         #[cfg(anchors)]
1059                                         OnchainClaim::Event(claim_event) => {
1060                                                 log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
1061                                                 #[cfg(debug_assertions)] {
1062                                                         let num_existing = self.pending_claim_events.iter()
1063                                                                 .filter(|entry| entry.0 == *_package_id).count();
1064                                                         assert!(num_existing == 0 || num_existing == 1);
1065                                                 }
1066                                                 self.pending_claim_events.retain(|event| event.0 != *_package_id);
1067                                                 self.pending_claim_events.push((*_package_id, claim_event));
1068                                         },
1069                                 }
1070                         }
1071                 }
1072                 for (ancestor_claim_txid, request) in bump_candidates.drain() {
1073                         self.pending_claim_requests.insert(ancestor_claim_txid.0, request);
1074                 }
1075                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
1076                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
1077                 let mut remove_request = Vec::new();
1078                 self.claimable_outpoints.retain(|_, ref v|
1079                         if v.1 >= height {
1080                         remove_request.push(v.0.clone());
1081                         false
1082                         } else { true });
1083                 for req in remove_request {
1084                         self.pending_claim_requests.remove(&req);
1085                 }
1086         }
1087
1088         pub(crate) fn is_output_spend_pending(&self, outpoint: &BitcoinOutPoint) -> bool {
1089                 self.claimable_outpoints.get(outpoint).is_some()
1090         }
1091
1092         pub(crate) fn get_relevant_txids(&self) -> Vec<(Txid, Option<BlockHash>)> {
1093                 let mut txids: Vec<(Txid, Option<BlockHash>)> = self.onchain_events_awaiting_threshold_conf
1094                         .iter()
1095                         .map(|entry| (entry.txid, entry.block_hash))
1096                         .collect();
1097                 txids.sort_unstable_by_key(|(txid, _)| *txid);
1098                 txids.dedup();
1099                 txids
1100         }
1101
1102         pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
1103                 self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
1104                 self.holder_htlc_sigs = None;
1105         }
1106
1107         // Normally holder HTLCs are signed at the same time as the holder commitment tx.  However,
1108         // in some configurations, the holder commitment tx has been signed and broadcast by a
1109         // ChannelMonitor replica, so we handle that case here.
1110         fn sign_latest_holder_htlcs(&mut self) {
1111                 if self.holder_htlc_sigs.is_none() {
1112                         let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
1113                         self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, sigs));
1114                 }
1115         }
1116
1117         // Normally only the latest commitment tx and HTLCs need to be signed.  However, in some
1118         // configurations we may have updated our holder commitment but a replica of the ChannelMonitor
1119         // broadcast the previous one before we sync with it.  We handle that case here.
1120         fn sign_prev_holder_htlcs(&mut self) {
1121                 if self.prev_holder_htlc_sigs.is_none() {
1122                         if let Some(ref holder_commitment) = self.prev_holder_commitment {
1123                                 let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(holder_commitment, &self.secp_ctx).expect("sign previous holder commitment");
1124                                 self.prev_holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
1125                         }
1126                 }
1127         }
1128
1129         fn extract_holder_sigs(holder_commitment: &HolderCommitmentTransaction, sigs: Vec<Signature>) -> Vec<Option<(usize, Signature)>> {
1130                 let mut ret = Vec::new();
1131                 for (htlc_idx, (holder_sig, htlc)) in sigs.iter().zip(holder_commitment.htlcs().iter()).enumerate() {
1132                         let tx_idx = htlc.transaction_output_index.unwrap();
1133                         if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
1134                         ret[tx_idx as usize] = Some((htlc_idx, holder_sig.clone()));
1135                 }
1136                 ret
1137         }
1138
1139         //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
1140         // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
1141         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
1142         // to monitor before.
1143         pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1144                 let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
1145                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
1146                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1147         }
1148
1149         #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
1150         pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1151                 let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
1152                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
1153                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1154         }
1155
1156         pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1157                 let mut htlc_tx = None;
1158                 let commitment_txid = self.holder_commitment.trust().txid();
1159                 // Check if the HTLC spends from the current holder commitment
1160                 if commitment_txid == outp.txid {
1161                         self.sign_latest_holder_htlcs();
1162                         if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
1163                                 let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1164                                 let trusted_tx = self.holder_commitment.trust();
1165                                 let counterparty_htlc_sig = self.holder_commitment.counterparty_htlc_sigs[*htlc_idx];
1166                                 htlc_tx = Some(trusted_tx
1167                                         .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
1168                         }
1169                 }
1170                 // If the HTLC doesn't spend the current holder commitment, check if it spends the previous one
1171                 if htlc_tx.is_none() && self.prev_holder_commitment.is_some() {
1172                         let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().trust().txid();
1173                         if commitment_txid == outp.txid {
1174                                 self.sign_prev_holder_htlcs();
1175                                 if let &Some(ref htlc_sigs) = &self.prev_holder_htlc_sigs {
1176                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1177                                         let holder_commitment = self.prev_holder_commitment.as_ref().unwrap();
1178                                         let trusted_tx = holder_commitment.trust();
1179                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[*htlc_idx];
1180                                         htlc_tx = Some(trusted_tx
1181                                                 .get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
1182                                 }
1183                         }
1184                 }
1185                 htlc_tx
1186         }
1187
1188         #[cfg(anchors)]
1189         pub(crate) fn generate_external_htlc_claim(
1190                 &self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
1191         ) -> Option<ExternalHTLCClaim> {
1192                 let find_htlc = |holder_commitment: &HolderCommitmentTransaction| -> Option<ExternalHTLCClaim> {
1193                         let trusted_tx = holder_commitment.trust();
1194                         if outp.txid != trusted_tx.txid() {
1195                                 return None;
1196                         }
1197                         trusted_tx.htlcs().iter().enumerate()
1198                                 .find(|(_, htlc)| if let Some(output_index) = htlc.transaction_output_index {
1199                                         output_index == outp.vout
1200                                 } else {
1201                                         false
1202                                 })
1203                                 .map(|(htlc_idx, htlc)| {
1204                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1205                                         ExternalHTLCClaim {
1206                                                 commitment_txid: trusted_tx.txid(),
1207                                                 per_commitment_number: trusted_tx.commitment_number(),
1208                                                 htlc: htlc.clone(),
1209                                                 preimage: *preimage,
1210                                                 counterparty_sig: counterparty_htlc_sig,
1211                                         }
1212                                 })
1213                 };
1214                 // Check if the HTLC spends from the current holder commitment or the previous one otherwise.
1215                 find_htlc(&self.holder_commitment)
1216                         .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
1217         }
1218
1219         pub(crate) fn opt_anchors(&self) -> bool {
1220                 self.channel_transaction_parameters.opt_anchors.is_some()
1221         }
1222
1223         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
1224         pub(crate) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1225                 let latest_had_sigs = self.holder_htlc_sigs.is_some();
1226                 let prev_had_sigs = self.prev_holder_htlc_sigs.is_some();
1227                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
1228                 if !latest_had_sigs {
1229                         self.holder_htlc_sigs = None;
1230                 }
1231                 if !prev_had_sigs {
1232                         self.prev_holder_htlc_sigs = None;
1233                 }
1234                 ret
1235         }
1236 }