_ 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::PackedLockTime;
  16 use bitcoin::blockdata::transaction::Transaction;
  17 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
  18 use bitcoin::blockdata::script::Script;
  19 use bitcoin::hashes::{Hash, HashEngine};
  20 use bitcoin::hashes::sha256::Hash as Sha256;
  21 use bitcoin::hash_types::{Txid, BlockHash};
  22 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
  23 use bitcoin::secp256k1;
  24
  25 use crate::chain::chaininterface::compute_feerate_sat_per_1000_weight;
  26 use crate::events::bump_transaction::{ChannelDerivationParameters, HTLCDescriptor};
  27 use crate::sign::{ChannelSigner, EntropySource, SignerProvider};
  28 use crate::ln::msgs::DecodeError;
  29 use crate::ln::PaymentPreimage;
  30 use crate::ln::chan_utils::{self, ChannelTransactionParameters, HTLCOutputInCommitment, HolderCommitmentTransaction};
  31 use crate::chain::ClaimId;
  32 use crate::chain::chaininterface::{ConfirmationTarget, FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator};
  33 use crate::chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER};
  34 use crate::sign::WriteableEcdsaChannelSigner;
  35 use crate::chain::package::{PackageSolvingData, PackageTemplate};
  36 use crate::util::logger::Logger;
  37 use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, UpgradableRequired, Writer, Writeable, VecWriter};
  38
  39 use crate::io;
  40 use crate::prelude::*;
  41 use alloc::collections::BTreeMap;
  42 use core::cmp;
  43 use core::ops::Deref;
  44 use core::mem::replace;
  45 use core::mem::swap;
  46 use crate::ln::features::ChannelTypeFeatures;
  47
  48 const MAX_ALLOC_SIZE: usize = 64*1024;
  49
  50 /// An entry for an [`OnchainEvent`], stating the block height when the event was observed and the
  51 /// transaction causing it.
  52 ///
  53 /// Used to determine when the on-chain event can be considered safe from a chain reorganization.
  54 #[derive(Clone, PartialEq, Eq)]
  55 struct OnchainEventEntry {
  56         txid: Txid,
  57         height: u32,
  58         block_hash: Option<BlockHash>, // Added as optional, will be filled in for any entry generated on 0.0.113 or after
  59         event: OnchainEvent,
  60 }
  61
  62 impl OnchainEventEntry {
  63         fn confirmation_threshold(&self) -> u32 {
  64                 self.height + ANTI_REORG_DELAY - 1
  65         }
  66
  67         fn has_reached_confirmation_threshold(&self, height: u32) -> bool {
  68                 height >= self.confirmation_threshold()
  69         }
  70 }
  71
  72 /// Events for claims the [`OnchainTxHandler`] has generated. Once the events are considered safe
  73 /// from a chain reorg, the [`OnchainTxHandler`] will act accordingly.
  74 #[derive(Clone, PartialEq, Eq)]
  75 enum OnchainEvent {
  76         /// A pending request has been claimed by a transaction spending the exact same set of outpoints
  77         /// as the request. This claim can either be ours or from the counterparty. Once the claiming
  78         /// transaction has met [`ANTI_REORG_DELAY`] confirmations, we consider it final and remove the
  79         /// pending request.
  80         Claim {
  81                 claim_id: ClaimId,
  82         },
  83         /// The counterparty has claimed an outpoint from one of our pending requests through a
  84         /// different transaction than ours. If our transaction was attempting to claim multiple
  85         /// outputs, we need to drop the outpoint claimed by the counterparty and regenerate a new claim
  86         /// transaction for ourselves. We keep tracking, separately, the outpoint claimed by the
  87         /// counterparty up to [`ANTI_REORG_DELAY`] confirmations to ensure we attempt to re-claim it
  88         /// if the counterparty's claim is reorged from the chain.
  89         ContentiousOutpoint {
  90                 package: PackageTemplate,
  91         }
  92 }
  93
  94 impl Writeable for OnchainEventEntry {
  95         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
  96                 write_tlv_fields!(writer, {
  97                         (0, self.txid, required),
  98                         (1, self.block_hash, option),
  99                         (2, self.height, required),
 100                         (4, self.event, required),
 101                 });
 102                 Ok(())
 103         }
 104 }
 105
 106 impl MaybeReadable for OnchainEventEntry {
 107         fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
 108                 let mut txid = Txid::all_zeros();
 109                 let mut height = 0;
 110                 let mut block_hash = None;
 111                 let mut event = UpgradableRequired(None);
 112                 read_tlv_fields!(reader, {
 113                         (0, txid, required),
 114                         (1, block_hash, option),
 115                         (2, height, required),
 116                         (4, event, upgradable_required),
 117                 });
 118                 Ok(Some(Self { txid, height, block_hash, event: _init_tlv_based_struct_field!(event, upgradable_required) }))
 119         }
 120 }
 121
 122 impl_writeable_tlv_based_enum_upgradable!(OnchainEvent,
 123         (0, Claim) => {
 124                 (0, claim_id, required),
 125         },
 126         (1, ContentiousOutpoint) => {
 127                 (0, package, required),
 128         },
 129 );
 130
 131 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 132         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 133                 match Readable::read(reader)? {
 134                         0u8 => Ok(None),
 135                         1u8 => {
 136                                 let vlen: u64 = Readable::read(reader)?;
 137                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::core::mem::size_of::<Option<(usize, Signature)>>()));
 138                                 for _ in 0..vlen {
 139                                         ret.push(match Readable::read(reader)? {
 140                                                 0u8 => None,
 141                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 142                                                 _ => return Err(DecodeError::InvalidValue)
 143                                         });
 144                                 }
 145                                 Ok(Some(ret))
 146                         },
 147                         _ => Err(DecodeError::InvalidValue),
 148                 }
 149         }
 150 }
 151
 152 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 153         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 154                 match self {
 155                         &Some(ref vec) => {
 156                                 1u8.write(writer)?;
 157                                 (vec.len() as u64).write(writer)?;
 158                                 for opt in vec.iter() {
 159                                         match opt {
 160                                                 &Some((ref idx, ref sig)) => {
 161                                                         1u8.write(writer)?;
 162                                                         (*idx as u64).write(writer)?;
 163                                                         sig.write(writer)?;
 164                                                 },
 165                                                 &None => 0u8.write(writer)?,
 166                                         }
 167                                 }
 168                         },
 169                         &None => 0u8.write(writer)?,
 170                 }
 171                 Ok(())
 172         }
 173 }
 174
 175 /// The claim commonly referred to as the pre-signed second-stage HTLC transaction.
 176 #[derive(Clone, PartialEq, Eq)]
 177 pub(crate) struct ExternalHTLCClaim {
 178         pub(crate) commitment_txid: Txid,
 179         pub(crate) per_commitment_number: u64,
 180         pub(crate) htlc: HTLCOutputInCommitment,
 181         pub(crate) preimage: Option<PaymentPreimage>,
 182         pub(crate) counterparty_sig: Signature,
 183 }
 184
 185 // Represents the different types of claims for which events are yielded externally to satisfy said
 186 // claims.
 187 #[derive(Clone, PartialEq, Eq)]
 188 pub(crate) enum ClaimEvent {
 189         /// Event yielded to signal that the commitment transaction fee must be bumped to claim any
 190         /// encumbered funds and proceed to HTLC resolution, if any HTLCs exist.
 191         BumpCommitment {
 192                 package_target_feerate_sat_per_1000_weight: u32,
 193                 commitment_tx: Transaction,
 194                 anchor_output_idx: u32,
 195         },
 196         /// Event yielded to signal that the commitment transaction has confirmed and its HTLCs must be
 197         /// resolved by broadcasting a transaction with sufficient fee to claim them.
 198         BumpHTLC {
 199                 target_feerate_sat_per_1000_weight: u32,
 200                 htlcs: Vec<ExternalHTLCClaim>,
 201                 tx_lock_time: PackedLockTime,
 202         },
 203 }
 204
 205 /// Represents the different ways an output can be claimed (i.e., spent to an address under our
 206 /// control) onchain.
 207 pub(crate) enum OnchainClaim {
 208         /// A finalized transaction pending confirmation spending the output to claim.
 209         Tx(Transaction),
 210         /// An event yielded externally to signal additional inputs must be added to a transaction
 211         /// pending confirmation spending the output to claim.
 212         Event(ClaimEvent),
 213 }
 214
 215 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 216 /// do RBF bumping if possible.
 217 #[derive(Clone)]
 218 pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
 219         channel_value_satoshis: u64,
 220         channel_keys_id: [u8; 32],
 221         destination_script: Script,
 222         holder_commitment: HolderCommitmentTransaction,
 223         // holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
 224         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 225         // the set of HTLCs in the HolderCommitmentTransaction.
 226         holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 227         prev_holder_commitment: Option<HolderCommitmentTransaction>,
 228         prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 229
 230         pub(super) signer: ChannelSigner,
 231         pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 232
 233         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 234         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 235         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 236         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 237         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 238         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 239         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 240         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 241         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 242         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 243         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 244         #[cfg(test)] // Used in functional_test to verify sanitization
 245         pub(crate) pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
 246         #[cfg(not(test))]
 247         pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
 248
 249         // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
 250         // essentially acts as an insertion-ordered `HashMap` – there should only ever be one occurrence
 251         // of a `ClaimId`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
 252         // a new block has been connected, resulting in a new claim, the previous will be replaced with
 253         // the new.
 254         //
 255         // These external events may be generated in the following cases:
 256         //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
 257         //      - A block being connected/disconnected
 258         //      - Learning the preimage for an HTLC we can claim onchain
 259         pending_claim_events: Vec<(ClaimId, ClaimEvent)>,
 260
 261         // Used to link outpoints claimed in a connected block to a pending claim request. The keys
 262         // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
 263         // claim. The values track the pending claim request identifier and the initial confirmation
 264         // block height, and are immutable until the outpoint has enough confirmations to meet our
 265         // [`ANTI_REORG_DELAY`]. The initial confirmation block height is used to remove the entry if
 266         // the block gets disconnected.
 267         #[cfg(test)] // Used in functional_test to verify sanitization
 268         pub claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
 269         #[cfg(not(test))]
 270         claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
 271
 272         locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
 273
 274         onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
 275
 276         pub(super) secp_ctx: Secp256k1<secp256k1::All>,
 277 }
 278
 279 impl<ChannelSigner: WriteableEcdsaChannelSigner> PartialEq for OnchainTxHandler<ChannelSigner> {
 280         fn eq(&self, other: &Self) -> bool {
 281                 // `signer`, `secp_ctx`, and `pending_claim_events` are excluded on purpose.
 282                 self.channel_value_satoshis == other.channel_value_satoshis &&
 283                         self.channel_keys_id == other.channel_keys_id &&
 284                         self.destination_script == other.destination_script &&
 285                         self.holder_commitment == other.holder_commitment &&
 286                         self.holder_htlc_sigs == other.holder_htlc_sigs &&
 287                         self.prev_holder_commitment == other.prev_holder_commitment &&
 288                         self.prev_holder_htlc_sigs == other.prev_holder_htlc_sigs &&
 289                         self.channel_transaction_parameters == other.channel_transaction_parameters &&
 290                         self.pending_claim_requests == other.pending_claim_requests &&
 291                         self.claimable_outpoints == other.claimable_outpoints &&
 292                         self.locktimed_packages == other.locktimed_packages &&
 293                         self.onchain_events_awaiting_threshold_conf == other.onchain_events_awaiting_threshold_conf
 294         }
 295 }
 296
 297 const SERIALIZATION_VERSION: u8 = 1;
 298 const MIN_SERIALIZATION_VERSION: u8 = 1;
 299
 300 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 301         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 302                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 303
 304                 self.destination_script.write(writer)?;
 305                 self.holder_commitment.write(writer)?;
 306                 self.holder_htlc_sigs.write(writer)?;
 307                 self.prev_holder_commitment.write(writer)?;
 308                 self.prev_holder_htlc_sigs.write(writer)?;
 309
 310                 self.channel_transaction_parameters.write(writer)?;
 311
 312                 let mut key_data = VecWriter(Vec::new());
 313                 self.signer.write(&mut key_data)?;
 314                 assert!(key_data.0.len() < core::usize::MAX);
 315                 assert!(key_data.0.len() < core::u32::MAX as usize);
 316                 (key_data.0.len() as u32).write(writer)?;
 317                 writer.write_all(&key_data.0[..])?;
 318
 319                 writer.write_all(&(self.pending_claim_requests.len() as u64).to_be_bytes())?;
 320                 for (ref ancestor_claim_txid, request) in self.pending_claim_requests.iter() {
 321                         ancestor_claim_txid.write(writer)?;
 322                         request.write(writer)?;
 323                 }
 324
 325                 writer.write_all(&(self.claimable_outpoints.len() as u64).to_be_bytes())?;
 326                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 327                         outp.write(writer)?;
 328                         claim_and_height.0.write(writer)?;
 329                         claim_and_height.1.write(writer)?;
 330                 }
 331
 332                 writer.write_all(&(self.locktimed_packages.len() as u64).to_be_bytes())?;
 333                 for (ref locktime, ref packages) in self.locktimed_packages.iter() {
 334                         locktime.write(writer)?;
 335                         writer.write_all(&(packages.len() as u64).to_be_bytes())?;
 336                         for ref package in packages.iter() {
 337                                 package.write(writer)?;
 338                         }
 339                 }
 340
 341                 writer.write_all(&(self.onchain_events_awaiting_threshold_conf.len() as u64).to_be_bytes())?;
 342                 for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
 343                         entry.write(writer)?;
 344                 }
 345
 346                 write_tlv_fields!(writer, {});
 347                 Ok(())
 348         }
 349 }
 350
 351 impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::Signer> {
 352         fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP, u64, [u8; 32])) -> Result<Self, DecodeError> {
 353                 let entropy_source = args.0;
 354                 let signer_provider = args.1;
 355                 let channel_value_satoshis = args.2;
 356                 let channel_keys_id = args.3;
 357
 358                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 359
 360                 let destination_script = Readable::read(reader)?;
 361
 362                 let holder_commitment = Readable::read(reader)?;
 363                 let holder_htlc_sigs = Readable::read(reader)?;
 364                 let prev_holder_commitment = Readable::read(reader)?;
 365                 let prev_holder_htlc_sigs = Readable::read(reader)?;
 366
 367                 let channel_parameters = Readable::read(reader)?;
 368
 369                 // Read the serialized signer bytes, but don't deserialize them, as we'll obtain our signer
 370                 // by re-deriving the private key material.
 371                 let keys_len: u32 = Readable::read(reader)?;
 372                 let mut bytes_read = 0;
 373                 while bytes_read != keys_len as usize {
 374                         // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
 375                         let mut data = [0; 1024];
 376                         let bytes_to_read = cmp::min(1024, keys_len as usize - bytes_read);
 377                         let read_slice = &mut data[0..bytes_to_read];
 378                         reader.read_exact(read_slice)?;
 379                         bytes_read += bytes_to_read;
 380                 }
 381
 382                 let mut signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
 383                 signer.provide_channel_parameters(&channel_parameters);
 384
 385                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 386                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 387                 for _ in 0..pending_claim_requests_len {
 388                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 389                 }
 390
 391                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 392                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 393                 for _ in 0..claimable_outpoints_len {
 394                         let outpoint = Readable::read(reader)?;
 395                         let ancestor_claim_txid = Readable::read(reader)?;
 396                         let height = Readable::read(reader)?;
 397                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 398                 }
 399
 400                 let locktimed_packages_len: u64 = Readable::read(reader)?;
 401                 let mut locktimed_packages = BTreeMap::new();
 402                 for _ in 0..locktimed_packages_len {
 403                         let locktime = Readable::read(reader)?;
 404                         let packages_len: u64 = Readable::read(reader)?;
 405                         let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
 406                         for _ in 0..packages_len {
 407                                 packages.push(Readable::read(reader)?);
 408                         }
 409                         locktimed_packages.insert(locktime, packages);
 410                 }
 411
 412                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 413                 let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 414                 for _ in 0..waiting_threshold_conf_len {
 415                         if let Some(val) = MaybeReadable::read(reader)? {
 416                                 onchain_events_awaiting_threshold_conf.push(val);
 417                         }
 418                 }
 419
 420                 read_tlv_fields!(reader, {});
 421
 422                 let mut secp_ctx = Secp256k1::new();
 423                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 424
 425                 Ok(OnchainTxHandler {
 426                         channel_value_satoshis,
 427                         channel_keys_id,
 428                         destination_script,
 429                         holder_commitment,
 430                         holder_htlc_sigs,
 431                         prev_holder_commitment,
 432                         prev_holder_htlc_sigs,
 433                         signer,
 434                         channel_transaction_parameters: channel_parameters,
 435                         claimable_outpoints,
 436                         locktimed_packages,
 437                         pending_claim_requests,
 438                         onchain_events_awaiting_threshold_conf,
 439                         pending_claim_events: Vec::new(),
 440                         secp_ctx,
 441                 })
 442         }
 443 }
 444
 445 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 446         pub(crate) fn new(
 447                 channel_value_satoshis: u64, channel_keys_id: [u8; 32], destination_script: Script,
 448                 signer: ChannelSigner, channel_parameters: ChannelTransactionParameters,
 449                 holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>
 450         ) -> Self {
 451                 OnchainTxHandler {
 452                         channel_value_satoshis,
 453                         channel_keys_id,
 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                         pending_claim_events: Vec::new(),
 466                         secp_ctx,
 467                 }
 468         }
 469
 470         pub(crate) fn get_prev_holder_commitment_to_self_value(&self) -> Option<u64> {
 471                 self.prev_holder_commitment.as_ref().map(|commitment| commitment.to_broadcaster_value_sat())
 472         }
 473
 474         pub(crate) fn get_cur_holder_commitment_to_self_value(&self) -> u64 {
 475                 self.holder_commitment.to_broadcaster_value_sat()
 476         }
 477
 478         pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
 479                 let mut events = Vec::new();
 480                 swap(&mut events, &mut self.pending_claim_events);
 481                 events
 482         }
 483
 484         /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
 485         /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
 486         /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
 487         /// invoking this every 30 seconds, or lower if running in an environment with spotty
 488         /// connections, like on mobile.
 489         pub(crate) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Deref>(
 490                 &mut self, current_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>,
 491                 logger: &L,
 492         )
 493         where
 494                 B::Target: BroadcasterInterface,
 495                 F::Target: FeeEstimator,
 496                 L::Target: Logger,
 497         {
 498                 let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
 499                 for (claim_id, request) in self.pending_claim_requests.iter() {
 500                         let inputs = request.outpoints();
 501                         log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
 502                         bump_requests.push((*claim_id, request.clone()));
 503                 }
 504                 for (claim_id, request) in bump_requests {
 505                         self.generate_claim(current_height, &request, false /* force_feerate_bump */, fee_estimator, logger)
 506                                 .map(|(_, new_feerate, claim)| {
 507                                         let mut bumped_feerate = false;
 508                                         if let Some(mut_request) = self.pending_claim_requests.get_mut(&claim_id) {
 509                                                 bumped_feerate = request.previous_feerate() > new_feerate;
 510                                                 mut_request.set_feerate(new_feerate);
 511                                         }
 512                                         match claim {
 513                                                 OnchainClaim::Tx(tx) => {
 514                                                         let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
 515                                                         log_info!(logger, "{} onchain {}", log_start, log_tx!(tx));
 516                                                         broadcaster.broadcast_transactions(&[&tx]);
 517                                                 },
 518                                                 OnchainClaim::Event(event) => {
 519                                                         let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" };
 520                                                         log_info!(logger, "{} onchain event to spend inputs {:?}", log_start,
 521                                                                 request.outpoints());
 522                                                         #[cfg(debug_assertions)] {
 523                                                                 debug_assert!(request.requires_external_funding());
 524                                                                 let num_existing = self.pending_claim_events.iter()
 525                                                                         .filter(|entry| entry.0 == claim_id).count();
 526                                                                 assert!(num_existing == 0 || num_existing == 1);
 527                                                         }
 528                                                         self.pending_claim_events.retain(|event| event.0 != claim_id);
 529                                                         self.pending_claim_events.push((claim_id, event));
 530                                                 }
 531                                         }
 532                                 });
 533                 }
 534         }
 535
 536         /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
 537         /// onchain) lays on the assumption of claim transactions getting confirmed before timelock
 538         /// expiration (CSV or CLTV following cases). In case of high-fee spikes, claim tx may get stuck
 539         /// in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or
 540         /// Child-Pay-For-Parent.
 541         ///
 542         /// Panics if there are signing errors, because signing operations in reaction to on-chain
 543         /// events are not expected to fail, and if they do, we may lose funds.
 544         fn generate_claim<F: Deref, L: Deref>(
 545                 &mut self, cur_height: u32, cached_request: &PackageTemplate, force_feerate_bump: bool,
 546                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 547         ) -> Option<(u32, u64, OnchainClaim)>
 548         where
 549                 F::Target: FeeEstimator,
 550                 L::Target: Logger,
 551         {
 552                 let request_outpoints = cached_request.outpoints();
 553                 if request_outpoints.is_empty() {
 554                         // Don't prune pending claiming request yet, we may have to resurrect HTLCs. Untractable
 555                         // packages cannot be aggregated and will never be split, so we cannot end up with an
 556                         // empty claim.
 557                         debug_assert!(cached_request.is_malleable());
 558                         return None;
 559                 }
 560                 // If we've seen transaction inclusion in the chain for all outpoints in our request, we
 561                 // don't need to continue generating more claims. We'll keep tracking the request to fully
 562                 // remove it once it reaches the confirmation threshold, or to generate a new claim if the
 563                 // transaction is reorged out.
 564                 let mut all_inputs_have_confirmed_spend = true;
 565                 for outpoint in request_outpoints.iter() {
 566                         if let Some((request_claim_id, _)) = self.claimable_outpoints.get(*outpoint) {
 567                                 // We check for outpoint spends within claims individually rather than as a set
 568                                 // since requests can have outpoints split off.
 569                                 if !self.onchain_events_awaiting_threshold_conf.iter()
 570                                         .any(|event_entry| if let OnchainEvent::Claim { claim_id } = event_entry.event {
 571                                                 *request_claim_id == claim_id
 572                                         } else {
 573                                                 // The onchain event is not a claim, keep seeking until we find one.
 574                                                 false
 575                                         })
 576                                 {
 577                                         // Either we had no `OnchainEvent::Claim`, or we did but none matched the
 578                                         // outpoint's registered spend.
 579                                         all_inputs_have_confirmed_spend = false;
 580                                 }
 581                         } else {
 582                                 // The request's outpoint spend does not exist yet.
 583                                 all_inputs_have_confirmed_spend = false;
 584                         }
 585                 }
 586                 if all_inputs_have_confirmed_spend {
 587                         return None;
 588                 }
 589
 590                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 591                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 592                 let new_timer = cached_request.get_height_timer(cur_height);
 593                 if cached_request.is_malleable() {
 594                         if cached_request.requires_external_funding() {
 595                                 let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
 596                                         fee_estimator, ConfirmationTarget::HighPriority, force_feerate_bump
 597                                 );
 598                                 if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
 599                                         return Some((
 600                                                 new_timer,
 601                                                 target_feerate_sat_per_1000_weight as u64,
 602                                                 OnchainClaim::Event(ClaimEvent::BumpHTLC {
 603                                                         target_feerate_sat_per_1000_weight,
 604                                                         htlcs,
 605                                                         tx_lock_time: PackedLockTime(cached_request.package_locktime(cur_height)),
 606                                                 }),
 607                                         ));
 608                                 } else {
 609                                         return None;
 610                                 }
 611                         }
 612
 613                         let predicted_weight = cached_request.package_weight(&self.destination_script);
 614                         if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
 615                                 predicted_weight, self.destination_script.dust_value().to_sat(),
 616                                 force_feerate_bump, fee_estimator, logger,
 617                         ) {
 618                                 assert!(new_feerate != 0);
 619
 620                                 let transaction = cached_request.finalize_malleable_package(
 621                                         cur_height, self, output_value, self.destination_script.clone(), logger
 622                                 ).unwrap();
 623                                 log_trace!(logger, "...with timer {} and feerate {}", new_timer, new_feerate);
 624                                 assert!(predicted_weight >= transaction.weight());
 625                                 return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
 626                         }
 627                 } else {
 628                         // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
 629                         // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
 630                         // which require external funding.
 631                         let mut inputs = cached_request.inputs();
 632                         debug_assert_eq!(inputs.len(), 1);
 633                         let tx = match cached_request.finalize_untractable_package(self, logger) {
 634                                 Some(tx) => tx,
 635                                 None => return None,
 636                         };
 637                         if !cached_request.requires_external_funding() {
 638                                 return Some((new_timer, 0, OnchainClaim::Tx(tx)));
 639                         }
 640                         return inputs.find_map(|input| match input {
 641                                 // Commitment inputs with anchors support are the only untractable inputs supported
 642                                 // thus far that require external funding.
 643                                 PackageSolvingData::HolderFundingOutput(output) => {
 644                                         debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(),
 645                                                 "Holder commitment transaction mismatch");
 646
 647                                         let conf_target = ConfirmationTarget::HighPriority;
 648                                         let package_target_feerate_sat_per_1000_weight = cached_request
 649                                                 .compute_package_feerate(fee_estimator, conf_target, force_feerate_bump);
 650                                         if let Some(input_amount_sat) = output.funding_amount {
 651                                                 let fee_sat = input_amount_sat - tx.output.iter().map(|output| output.value).sum::<u64>();
 652                                                 let commitment_tx_feerate_sat_per_1000_weight =
 653                                                         compute_feerate_sat_per_1000_weight(fee_sat, tx.weight() as u64);
 654                                                 if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
 655                                                         log_debug!(logger, "Pre-signed {} already has feerate {} sat/kW above required {} sat/kW",
 656                                                                 log_tx!(tx), commitment_tx_feerate_sat_per_1000_weight,
 657                                                                 package_target_feerate_sat_per_1000_weight);
 658                                                         return Some((new_timer, 0, OnchainClaim::Tx(tx.clone())));
 659                                                 }
 660                                         }
 661
 662                                         // We'll locate an anchor output we can spend within the commitment transaction.
 663                                         let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
 664                                         match chan_utils::get_anchor_output(&tx, funding_pubkey) {
 665                                                 // An anchor output was found, so we should yield a funding event externally.
 666                                                 Some((idx, _)) => {
 667                                                         // TODO: Use a lower confirmation target when both our and the
 668                                                         // counterparty's latest commitment don't have any HTLCs present.
 669                                                         Some((
 670                                                                 new_timer,
 671                                                                 package_target_feerate_sat_per_1000_weight as u64,
 672                                                                 OnchainClaim::Event(ClaimEvent::BumpCommitment {
 673                                                                         package_target_feerate_sat_per_1000_weight,
 674                                                                         commitment_tx: tx.clone(),
 675                                                                         anchor_output_idx: idx,
 676                                                                 }),
 677                                                         ))
 678                                                 },
 679                                                 // An anchor output was not found. There's nothing we can do other than
 680                                                 // attempt to broadcast the transaction with its current fee rate and hope
 681                                                 // it confirms. This is essentially the same behavior as a commitment
 682                                                 // transaction without anchor outputs.
 683                                                 None => Some((new_timer, 0, OnchainClaim::Tx(tx.clone()))),
 684                                         }
 685                                 },
 686                                 _ => {
 687                                         debug_assert!(false, "Only HolderFundingOutput inputs should be untractable and require external funding");
 688                                         None
 689                                 },
 690                         })
 691                 }
 692                 None
 693         }
 694
 695         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 696         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 697         /// Together with `update_claims_view_from_matched_txn` this used to be named
 698         /// `block_connected`, but it is now also used for claiming an HTLC output if we receive a
 699         /// preimage after force-close.
 700         ///
 701         /// `conf_height` represents the height at which the request was generated. This
 702         /// does not need to equal the current blockchain tip height, which should be provided via
 703         /// `cur_height`, however it must never be higher than `cur_height`.
 704         pub(crate) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Deref>(
 705                 &mut self, requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32,
 706                 broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 707         ) where
 708                 B::Target: BroadcasterInterface,
 709                 F::Target: FeeEstimator,
 710                 L::Target: Logger,
 711         {
 712                 log_debug!(logger, "Updating claims view at height {} with {} claim requests", cur_height, requests.len());
 713                 let mut preprocessed_requests = Vec::with_capacity(requests.len());
 714                 let mut aggregated_request = None;
 715
 716                 // Try to aggregate outputs if their timelock expiration isn't imminent (package timelock
 717                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 718                 for req in requests {
 719                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 720                         if let Some(_) = self.claimable_outpoints.get(req.outpoints()[0]) {
 721                                 log_info!(logger, "Ignoring second claim for outpoint {}:{}, already registered its claiming request", req.outpoints()[0].txid, req.outpoints()[0].vout);
 722                         } else {
 723                                 let timelocked_equivalent_package = self.locktimed_packages.iter().map(|v| v.1.iter()).flatten()
 724                                         .find(|locked_package| locked_package.outpoints() == req.outpoints());
 725                                 if let Some(package) = timelocked_equivalent_package {
 726                                         log_info!(logger, "Ignoring second claim for outpoint {}:{}, we already have one which we're waiting on a timelock at {} for.",
 727                                                 req.outpoints()[0].txid, req.outpoints()[0].vout, package.package_locktime(cur_height));
 728                                         continue;
 729                                 }
 730
 731                                 let package_locktime = req.package_locktime(cur_height);
 732                                 if package_locktime > cur_height + 1 {
 733                                         log_info!(logger, "Delaying claim of package until its timelock at {} (current height {}), the following outpoints are spent:", package_locktime, cur_height);
 734                                         for outpoint in req.outpoints() {
 735                                                 log_info!(logger, "  Outpoint {}", outpoint);
 736                                         }
 737                                         self.locktimed_packages.entry(package_locktime).or_insert(Vec::new()).push(req);
 738                                         continue;
 739                                 }
 740
 741                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.timelock(), cur_height + CLTV_SHARED_CLAIM_BUFFER);
 742                                 if req.timelock() <= cur_height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable() {
 743                                         // Don't aggregate if outpoint package timelock is soon or marked as non-aggregable
 744                                         preprocessed_requests.push(req);
 745                                 } else if aggregated_request.is_none() {
 746                                         aggregated_request = Some(req);
 747                                 } else {
 748                                         aggregated_request.as_mut().unwrap().merge_package(req);
 749                                 }
 750                         }
 751                 }
 752                 if let Some(req) = aggregated_request {
 753                         preprocessed_requests.push(req);
 754                 }
 755
 756                 // Claim everything up to and including `cur_height`
 757                 let remaining_locked_packages = self.locktimed_packages.split_off(&(cur_height + 1));
 758                 for (pop_height, mut entry) in self.locktimed_packages.iter_mut() {
 759                         log_trace!(logger, "Restoring delayed claim of package(s) at their timelock at {}.", pop_height);
 760                         preprocessed_requests.append(&mut entry);
 761                 }
 762                 self.locktimed_packages = remaining_locked_packages;
 763
 764                 // Generate claim transactions and track them to bump if necessary at
 765                 // height timer expiration (i.e in how many blocks we're going to take action).
 766                 for mut req in preprocessed_requests {
 767                         if let Some((new_timer, new_feerate, claim)) = self.generate_claim(
 768                                 cur_height, &req, true /* force_feerate_bump */, &*fee_estimator, &*logger,
 769                         ) {
 770                                 req.set_timer(new_timer);
 771                                 req.set_feerate(new_feerate);
 772                                 // Once a pending claim has an id assigned, it remains fixed until the claim is
 773                                 // satisfied, regardless of whether the claim switches between different variants of
 774                                 // `OnchainClaim`.
 775                                 let claim_id = match claim {
 776                                         OnchainClaim::Tx(tx) => {
 777                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(tx));
 778                                                 broadcaster.broadcast_transactions(&[&tx]);
 779                                                 ClaimId(tx.txid().into_inner())
 780                                         },
 781                                         OnchainClaim::Event(claim_event) => {
 782                                                 log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
 783                                                 let claim_id = match claim_event {
 784                                                         ClaimEvent::BumpCommitment { ref commitment_tx, .. } =>
 785                                                                 // For commitment claims, we can just use their txid as it should
 786                                                                 // already be unique.
 787                                                                 ClaimId(commitment_tx.txid().into_inner()),
 788                                                         ClaimEvent::BumpHTLC { ref htlcs, .. } => {
 789                                                                 // For HTLC claims, commit to the entire set of HTLC outputs to
 790                                                                 // claim, which will always be unique per request. Once a claim ID
 791                                                                 // is generated, it is assigned and remains unchanged, even if the
 792                                                                 // underlying set of HTLCs changes.
 793                                                                 let mut engine = Sha256::engine();
 794                                                                 for htlc in htlcs {
 795                                                                         engine.input(&htlc.commitment_txid.into_inner());
 796                                                                         engine.input(&htlc.htlc.transaction_output_index.unwrap().to_be_bytes());
 797                                                                 }
 798                                                                 ClaimId(Sha256::from_engine(engine).into_inner())
 799                                                         },
 800                                                 };
 801                                                 debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
 802                                                 debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == claim_id).count(), 0);
 803                                                 self.pending_claim_events.push((claim_id, claim_event));
 804                                                 claim_id
 805                                         },
 806                                 };
 807                                 debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
 808                                 for k in req.outpoints() {
 809                                         log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 810                                         self.claimable_outpoints.insert(k.clone(), (claim_id, conf_height));
 811                                 }
 812                                 self.pending_claim_requests.insert(claim_id, req);
 813                         }
 814                 }
 815         }
 816
 817         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 818         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 819         /// Together with `update_claims_view_from_requests` this used to be named `block_connected`,
 820         /// but it is now also used for claiming an HTLC output if we receive a preimage after force-close.
 821         ///
 822         /// `conf_height` represents the height at which the transactions in `txn_matched` were
 823         /// confirmed. This does not need to equal the current blockchain tip height, which should be
 824         /// provided via `cur_height`, however it must never be higher than `cur_height`.
 825         pub(crate) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Deref>(
 826                 &mut self, txn_matched: &[&Transaction], conf_height: u32, conf_hash: BlockHash,
 827                 cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 828         ) where
 829                 B::Target: BroadcasterInterface,
 830                 F::Target: FeeEstimator,
 831                 L::Target: Logger,
 832         {
 833                 log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {}", cur_height, txn_matched.len(), conf_height);
 834                 let mut bump_candidates = HashMap::new();
 835                 for tx in txn_matched {
 836                         // Scan all input to verify is one of the outpoint spent is of interest for us
 837                         let mut claimed_outputs_material = Vec::new();
 838                         for inp in &tx.input {
 839                                 if let Some((claim_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
 840                                         // If outpoint has claim request pending on it...
 841                                         if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
 842                                                 //... we need to verify equality between transaction outpoints and claim request
 843                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 844                                                 // by us.
 845                                                 let mut are_sets_equal = true;
 846                                                 let mut tx_inputs = tx.input.iter().map(|input| &input.previous_output).collect::<Vec<_>>();
 847                                                 tx_inputs.sort_unstable();
 848                                                 for request_input in request.outpoints() {
 849                                                         if tx_inputs.binary_search(&request_input).is_err() {
 850                                                                 are_sets_equal = false;
 851                                                                 break;
 852                                                         }
 853                                                 }
 854
 855                                                 macro_rules! clean_claim_request_after_safety_delay {
 856                                                         () => {
 857                                                                 let entry = OnchainEventEntry {
 858                                                                         txid: tx.txid(),
 859                                                                         height: conf_height,
 860                                                                         block_hash: Some(conf_hash),
 861                                                                         event: OnchainEvent::Claim { claim_id: *claim_id }
 862                                                                 };
 863                                                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 864                                                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 865                                                                 }
 866                                                         }
 867                                                 }
 868
 869                                                 // If this is our transaction (or our counterparty spent all the outputs
 870                                                 // before we could anyway with same inputs order than us), wait for
 871                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 872                                                 if are_sets_equal {
 873                                                         clean_claim_request_after_safety_delay!();
 874                                                 } else { // If false, generate new claim request with update outpoint set
 875                                                         let mut at_least_one_drop = false;
 876                                                         for input in tx.input.iter() {
 877                                                                 if let Some(package) = request.split_package(&input.previous_output) {
 878                                                                         claimed_outputs_material.push(package);
 879                                                                         at_least_one_drop = true;
 880                                                                 }
 881                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 882                                                                 if request.outpoints().is_empty() {
 883                                                                         clean_claim_request_after_safety_delay!();
 884                                                                 }
 885                                                         }
 886                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 887                                                         if at_least_one_drop {
 888                                                                 bump_candidates.insert(*claim_id, request.clone());
 889                                                                 // If we have any pending claim events for the request being updated
 890                                                                 // that have yet to be consumed, we'll remove them since they will
 891                                                                 // end up producing an invalid transaction by double spending
 892                                                                 // input(s) that already have a confirmed spend. If such spend is
 893                                                                 // reorged out of the chain, then we'll attempt to re-spend the
 894                                                                 // inputs once we see it.
 895                                                                 #[cfg(debug_assertions)] {
 896                                                                         let existing = self.pending_claim_events.iter()
 897                                                                                 .filter(|entry| entry.0 == *claim_id).count();
 898                                                                         assert!(existing == 0 || existing == 1);
 899                                                                 }
 900                                                                 self.pending_claim_events.retain(|entry| entry.0 != *claim_id);
 901                                                         }
 902                                                 }
 903                                                 break; //No need to iterate further, either tx is our or their
 904                                         } else {
 905                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 906                                         }
 907                                 }
 908                         }
 909                         for package in claimed_outputs_material.drain(..) {
 910                                 let entry = OnchainEventEntry {
 911                                         txid: tx.txid(),
 912                                         height: conf_height,
 913                                         block_hash: Some(conf_hash),
 914                                         event: OnchainEvent::ContentiousOutpoint { package },
 915                                 };
 916                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 917                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 918                                 }
 919                         }
 920                 }
 921
 922                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 923                 let onchain_events_awaiting_threshold_conf =
 924                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
 925                 for entry in onchain_events_awaiting_threshold_conf {
 926                         if entry.has_reached_confirmation_threshold(cur_height) {
 927                                 match entry.event {
 928                                         OnchainEvent::Claim { claim_id } => {
 929                                                 // We may remove a whole set of claim outpoints here, as these one may have
 930                                                 // been aggregated in a single tx and claimed so atomically
 931                                                 if let Some(request) = self.pending_claim_requests.remove(&claim_id) {
 932                                                         for outpoint in request.outpoints() {
 933                                                                 log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
 934                                                                         outpoint, log_bytes!(claim_id.0));
 935                                                                 self.claimable_outpoints.remove(outpoint);
 936                                                         }
 937                                                         #[cfg(debug_assertions)] {
 938                                                                 let num_existing = self.pending_claim_events.iter()
 939                                                                         .filter(|entry| entry.0 == claim_id).count();
 940                                                                 assert!(num_existing == 0 || num_existing == 1);
 941                                                         }
 942                                                         self.pending_claim_events.retain(|(id, _)| *id != claim_id);
 943                                                 }
 944                                         },
 945                                         OnchainEvent::ContentiousOutpoint { package } => {
 946                                                 log_debug!(logger, "Removing claim tracking due to maturation of claim tx for outpoints:");
 947                                                 log_debug!(logger, " {:?}", package.outpoints());
 948                                                 self.claimable_outpoints.remove(package.outpoints()[0]);
 949                                         }
 950                                 }
 951                         } else {
 952                                 self.onchain_events_awaiting_threshold_conf.push(entry);
 953                         }
 954                 }
 955
 956                 // Check if any pending claim request must be rescheduled
 957                 for (claim_id, request) in self.pending_claim_requests.iter() {
 958                         if cur_height >= request.timer() {
 959                                 bump_candidates.insert(*claim_id, request.clone());
 960                         }
 961                 }
 962
 963                 // Build, bump and rebroadcast tx accordingly
 964                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 965                 for (claim_id, request) in bump_candidates.iter() {
 966                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
 967                                 cur_height, &request, true /* force_feerate_bump */, &*fee_estimator, &*logger,
 968                         ) {
 969                                 match bump_claim {
 970                                         OnchainClaim::Tx(bump_tx) => {
 971                                                 log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx));
 972                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
 973                                         },
 974                                         OnchainClaim::Event(claim_event) => {
 975                                                 log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
 976                                                 #[cfg(debug_assertions)] {
 977                                                         let num_existing = self.pending_claim_events.iter().
 978                                                                 filter(|entry| entry.0 == *claim_id).count();
 979                                                         assert!(num_existing == 0 || num_existing == 1);
 980                                                 }
 981                                                 self.pending_claim_events.retain(|event| event.0 != *claim_id);
 982                                                 self.pending_claim_events.push((*claim_id, claim_event));
 983                                         },
 984                                 }
 985                                 if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
 986                                         request.set_timer(new_timer);
 987                                         request.set_feerate(new_feerate);
 988                                 }
 989                         }
 990                 }
 991         }
 992
 993         pub(crate) fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
 994                 &mut self,
 995                 txid: &Txid,
 996                 broadcaster: B,
 997                 fee_estimator: &LowerBoundedFeeEstimator<F>,
 998                 logger: L,
 999         ) where
1000                 B::Target: BroadcasterInterface,
1001                 F::Target: FeeEstimator,
1002                 L::Target: Logger,
1003         {
1004                 let mut height = None;
1005                 for entry in self.onchain_events_awaiting_threshold_conf.iter() {
1006                         if entry.txid == *txid {
1007                                 height = Some(entry.height);
1008                                 break;
1009                         }
1010                 }
1011
1012                 if let Some(height) = height {
1013                         self.block_disconnected(height, broadcaster, fee_estimator, logger);
1014                 }
1015         }
1016
1017         pub(crate) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L)
1018                 where B::Target: BroadcasterInterface,
1019                       F::Target: FeeEstimator,
1020                                         L::Target: Logger,
1021         {
1022                 let mut bump_candidates = HashMap::new();
1023                 let onchain_events_awaiting_threshold_conf =
1024                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
1025                 for entry in onchain_events_awaiting_threshold_conf {
1026                         if entry.height >= height {
1027                                 //- our claim tx on a commitment tx output
1028                                 //- resurect outpoint back in its claimable set and regenerate tx
1029                                 match entry.event {
1030                                         OnchainEvent::ContentiousOutpoint { package } => {
1031                                                 if let Some(pending_claim) = self.claimable_outpoints.get(package.outpoints()[0]) {
1032                                                         if let Some(request) = self.pending_claim_requests.get_mut(&pending_claim.0) {
1033                                                                 request.merge_package(package);
1034                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
1035                                                                 // resurrected only one bump claim tx is going to be broadcast
1036                                                                 bump_candidates.insert(pending_claim.clone(), request.clone());
1037                                                         }
1038                                                 }
1039                                         },
1040                                         _ => {},
1041                                 }
1042                         } else {
1043                                 self.onchain_events_awaiting_threshold_conf.push(entry);
1044                         }
1045                 }
1046                 for ((_claim_id, _), ref mut request) in bump_candidates.iter_mut() {
1047                         // `height` is the height being disconnected, so our `current_height` is 1 lower.
1048                         let current_height = height - 1;
1049                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
1050                                 current_height, &request, true /* force_feerate_bump */, fee_estimator, &&*logger
1051                         ) {
1052                                 request.set_timer(new_timer);
1053                                 request.set_feerate(new_feerate);
1054                                 match bump_claim {
1055                                         OnchainClaim::Tx(bump_tx) => {
1056                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx));
1057                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
1058                                         },
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 == *_claim_id).count();
1064                                                         assert!(num_existing == 0 || num_existing == 1);
1065                                                 }
1066                                                 self.pending_claim_events.retain(|event| event.0 != *_claim_id);
1067                                                 self.pending_claim_events.push((*_claim_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         pub(crate) fn get_unsigned_holder_commitment_tx(&self) -> &Transaction {
1140                 &self.holder_commitment.trust().built_transaction().transaction
1141         }
1142
1143         //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
1144         // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created,
1145         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
1146         // to monitor before.
1147         pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1148                 let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
1149                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
1150                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1151         }
1152
1153         #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
1154         pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1155                 let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
1156                 self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
1157                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1158         }
1159
1160         pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1161                 let get_signed_htlc_tx = |holder_commitment: &HolderCommitmentTransaction| {
1162                         let trusted_tx = holder_commitment.trust();
1163                         if trusted_tx.txid() != outp.txid {
1164                                 return None;
1165                         }
1166                         let (htlc_idx, htlc) = trusted_tx.htlcs().iter().enumerate()
1167                                 .find(|(_, htlc)| htlc.transaction_output_index.unwrap() == outp.vout)
1168                                 .unwrap();
1169                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1170                         let mut htlc_tx = trusted_tx.build_unsigned_htlc_tx(
1171                                 &self.channel_transaction_parameters.as_holder_broadcastable(), htlc_idx, preimage,
1172                         );
1173
1174                         let htlc_descriptor = HTLCDescriptor {
1175                                 channel_derivation_parameters: ChannelDerivationParameters {
1176                                         value_satoshis: self.channel_value_satoshis,
1177                                         keys_id: self.channel_keys_id,
1178                                         transaction_parameters: self.channel_transaction_parameters.clone(),
1179                                 },
1180                                 commitment_txid: trusted_tx.txid(),
1181                                 per_commitment_number: trusted_tx.commitment_number(),
1182                                 per_commitment_point: trusted_tx.per_commitment_point(),
1183                                 feerate_per_kw: trusted_tx.feerate_per_kw(),
1184                                 htlc: htlc.clone(),
1185                                 preimage: preimage.clone(),
1186                                 counterparty_sig: counterparty_htlc_sig.clone(),
1187                         };
1188                         let htlc_sig = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx).unwrap();
1189                         htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness(
1190                                 htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage,
1191                         );
1192                         Some(htlc_tx)
1193                 };
1194
1195                 // Check if the HTLC spends from the current holder commitment first, or the previous.
1196                 get_signed_htlc_tx(&self.holder_commitment)
1197                         .or_else(|| self.prev_holder_commitment.as_ref().and_then(|prev_holder_commitment| get_signed_htlc_tx(prev_holder_commitment)))
1198         }
1199
1200         pub(crate) fn generate_external_htlc_claim(
1201                 &self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
1202         ) -> Option<ExternalHTLCClaim> {
1203                 let find_htlc = |holder_commitment: &HolderCommitmentTransaction| -> Option<ExternalHTLCClaim> {
1204                         let trusted_tx = holder_commitment.trust();
1205                         if outp.txid != trusted_tx.txid() {
1206                                 return None;
1207                         }
1208                         trusted_tx.htlcs().iter().enumerate()
1209                                 .find(|(_, htlc)| if let Some(output_index) = htlc.transaction_output_index {
1210                                         output_index == outp.vout
1211                                 } else {
1212                                         false
1213                                 })
1214                                 .map(|(htlc_idx, htlc)| {
1215                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1216                                         ExternalHTLCClaim {
1217                                                 commitment_txid: trusted_tx.txid(),
1218                                                 per_commitment_number: trusted_tx.commitment_number(),
1219                                                 htlc: htlc.clone(),
1220                                                 preimage: *preimage,
1221                                                 counterparty_sig: counterparty_htlc_sig,
1222                                         }
1223                                 })
1224                 };
1225                 // Check if the HTLC spends from the current holder commitment or the previous one otherwise.
1226                 find_htlc(&self.holder_commitment)
1227                         .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
1228         }
1229
1230         pub(crate) fn channel_type_features(&self) -> &ChannelTypeFeatures {
1231                 &self.channel_transaction_parameters.channel_type_features
1232         }
1233
1234         #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
1235         pub(crate) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1236                 let latest_had_sigs = self.holder_htlc_sigs.is_some();
1237                 let prev_had_sigs = self.prev_holder_htlc_sigs.is_some();
1238                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
1239                 if !latest_had_sigs {
1240                         self.holder_htlc_sigs = None;
1241                 }
1242                 if !prev_had_sigs {
1243                         self.prev_holder_htlc_sigs = None;
1244                 }
1245                 ret
1246         }
1247 }