_ 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::amount::Amount;
  16 use bitcoin::blockdata::locktime::absolute::LockTime;
  17 use bitcoin::blockdata::transaction::Transaction;
  18 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
  19 use bitcoin::blockdata::script::{Script, ScriptBuf};
  20 use bitcoin::hashes::{Hash, HashEngine};
  21 use bitcoin::hashes::sha256::Hash as Sha256;
  22 use bitcoin::hash_types::{Txid, BlockHash};
  23 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
  24 use bitcoin::secp256k1;
  25
  26 use crate::chain::chaininterface::compute_feerate_sat_per_1000_weight;
  27 use crate::sign::{ChannelDerivationParameters, HTLCDescriptor, ChannelSigner, EntropySource, SignerProvider, ecdsa::EcdsaChannelSigner};
  28 use crate::ln::msgs::DecodeError;
  29 use crate::ln::types::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::chain::package::{PackageSolvingData, PackageTemplate};
  35 use crate::chain::transaction::MaybeSignedTransaction;
  36 use crate::util::logger::Logger;
  37 use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, UpgradableRequired, Writer, Writeable};
  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: LockTime,
 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(MaybeSignedTransaction),
 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 /// Represents the different feerate strategies a pending request can use when generating a claim.
 216 pub(crate) enum FeerateStrategy {
 217         /// We must reuse the most recently used feerate, if any.
 218         RetryPrevious,
 219         /// We must pick the highest between the most recently used and the current feerate estimate.
 220         HighestOfPreviousOrNew,
 221         /// We must force a bump of the most recently used feerate, either by using the current feerate
 222         /// estimate if it's higher, or manually bumping.
 223         ForceBump,
 224 }
 225
 226 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 227 /// do RBF bumping if possible.
 228 #[derive(Clone)]
 229 pub struct OnchainTxHandler<ChannelSigner: EcdsaChannelSigner> {
 230         channel_value_satoshis: u64,
 231         channel_keys_id: [u8; 32],
 232         destination_script: ScriptBuf,
 233         holder_commitment: HolderCommitmentTransaction,
 234         prev_holder_commitment: Option<HolderCommitmentTransaction>,
 235
 236         pub(super) signer: ChannelSigner,
 237         pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 238
 239         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 240         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 241         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 242         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 243         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 244         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 245         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 246         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 247         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 248         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 249         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 250         #[cfg(test)] // Used in functional_test to verify sanitization
 251         pub(crate) pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
 252         #[cfg(not(test))]
 253         pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
 254
 255         // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
 256         // essentially acts as an insertion-ordered `HashMap` – there should only ever be one occurrence
 257         // of a `ClaimId`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
 258         // a new block has been connected, resulting in a new claim, the previous will be replaced with
 259         // the new.
 260         //
 261         // These external events may be generated in the following cases:
 262         //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
 263         //      - A block being connected/disconnected
 264         //      - Learning the preimage for an HTLC we can claim onchain
 265         pending_claim_events: Vec<(ClaimId, ClaimEvent)>,
 266
 267         // Used to link outpoints claimed in a connected block to a pending claim request. The keys
 268         // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
 269         // claim. The values track the pending claim request identifier and the initial confirmation
 270         // block height, and are immutable until the outpoint has enough confirmations to meet our
 271         // [`ANTI_REORG_DELAY`]. The initial confirmation block height is used to remove the entry if
 272         // the block gets disconnected.
 273         #[cfg(test)] // Used in functional_test to verify sanitization
 274         pub claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
 275         #[cfg(not(test))]
 276         claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
 277
 278         locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
 279
 280         onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
 281
 282         pub(super) secp_ctx: Secp256k1<secp256k1::All>,
 283 }
 284
 285 impl<ChannelSigner: EcdsaChannelSigner> PartialEq for OnchainTxHandler<ChannelSigner> {
 286         fn eq(&self, other: &Self) -> bool {
 287                 // `signer`, `secp_ctx`, and `pending_claim_events` are excluded on purpose.
 288                 self.channel_value_satoshis == other.channel_value_satoshis &&
 289                         self.channel_keys_id == other.channel_keys_id &&
 290                         self.destination_script == other.destination_script &&
 291                         self.holder_commitment == other.holder_commitment &&
 292                         self.prev_holder_commitment == other.prev_holder_commitment &&
 293                         self.channel_transaction_parameters == other.channel_transaction_parameters &&
 294                         self.pending_claim_requests == other.pending_claim_requests &&
 295                         self.claimable_outpoints == other.claimable_outpoints &&
 296                         self.locktimed_packages == other.locktimed_packages &&
 297                         self.onchain_events_awaiting_threshold_conf == other.onchain_events_awaiting_threshold_conf
 298         }
 299 }
 300
 301 const SERIALIZATION_VERSION: u8 = 1;
 302 const MIN_SERIALIZATION_VERSION: u8 = 1;
 303
 304 impl<ChannelSigner: EcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 305         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 306                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 307
 308                 self.destination_script.write(writer)?;
 309                 self.holder_commitment.write(writer)?;
 310                 None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // holder_htlc_sigs
 311                 self.prev_holder_commitment.write(writer)?;
 312                 None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // prev_holder_htlc_sigs
 313
 314                 self.channel_transaction_parameters.write(writer)?;
 315
 316                 // Write a zero-length signer. The data is no longer deserialized as of version 0.0.113 and
 317                 // downgrades before version 0.0.113 are no longer supported as of version 0.0.119.
 318                 0u32.write(writer)?;
 319
 320                 writer.write_all(&(self.pending_claim_requests.len() as u64).to_be_bytes())?;
 321                 for (ref ancestor_claim_txid, request) in self.pending_claim_requests.iter() {
 322                         ancestor_claim_txid.write(writer)?;
 323                         request.write(writer)?;
 324                 }
 325
 326                 writer.write_all(&(self.claimable_outpoints.len() as u64).to_be_bytes())?;
 327                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 328                         outp.write(writer)?;
 329                         claim_and_height.0.write(writer)?;
 330                         claim_and_height.1.write(writer)?;
 331                 }
 332
 333                 writer.write_all(&(self.locktimed_packages.len() as u64).to_be_bytes())?;
 334                 for (ref locktime, ref packages) in self.locktimed_packages.iter() {
 335                         locktime.write(writer)?;
 336                         writer.write_all(&(packages.len() as u64).to_be_bytes())?;
 337                         for ref package in packages.iter() {
 338                                 package.write(writer)?;
 339                         }
 340                 }
 341
 342                 writer.write_all(&(self.onchain_events_awaiting_threshold_conf.len() as u64).to_be_bytes())?;
 343                 for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
 344                         entry.write(writer)?;
 345                 }
 346
 347                 write_tlv_fields!(writer, {});
 348                 Ok(())
 349         }
 350 }
 351
 352 impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::EcdsaSigner> {
 353         fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP, u64, [u8; 32])) -> Result<Self, DecodeError> {
 354                 let entropy_source = args.0;
 355                 let signer_provider = args.1;
 356                 let channel_value_satoshis = args.2;
 357                 let channel_keys_id = args.3;
 358
 359                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 360
 361                 let destination_script = Readable::read(reader)?;
 362
 363                 let holder_commitment = Readable::read(reader)?;
 364                 let _holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
 365                 let prev_holder_commitment = Readable::read(reader)?;
 366                 let _prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
 367
 368                 let channel_parameters = Readable::read(reader)?;
 369
 370                 // Read the serialized signer bytes, but don't deserialize them, as we'll obtain our signer
 371                 // by re-deriving the private key material.
 372                 let keys_len: u32 = Readable::read(reader)?;
 373                 let mut bytes_read = 0;
 374                 while bytes_read != keys_len as usize {
 375                         // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
 376                         let mut data = [0; 1024];
 377                         let bytes_to_read = cmp::min(1024, keys_len as usize - bytes_read);
 378                         let read_slice = &mut data[0..bytes_to_read];
 379                         reader.read_exact(read_slice)?;
 380                         bytes_read += bytes_to_read;
 381                 }
 382
 383                 let mut signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
 384                 signer.provide_channel_parameters(&channel_parameters);
 385
 386                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 387                 let mut pending_claim_requests = hash_map_with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 388                 for _ in 0..pending_claim_requests_len {
 389                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 390                 }
 391
 392                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 393                 let mut claimable_outpoints = hash_map_with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 394                 for _ in 0..claimable_outpoints_len {
 395                         let outpoint = Readable::read(reader)?;
 396                         let ancestor_claim_txid = Readable::read(reader)?;
 397                         let height = Readable::read(reader)?;
 398                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 399                 }
 400
 401                 let locktimed_packages_len: u64 = Readable::read(reader)?;
 402                 let mut locktimed_packages = BTreeMap::new();
 403                 for _ in 0..locktimed_packages_len {
 404                         let locktime = Readable::read(reader)?;
 405                         let packages_len: u64 = Readable::read(reader)?;
 406                         let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
 407                         for _ in 0..packages_len {
 408                                 packages.push(Readable::read(reader)?);
 409                         }
 410                         locktimed_packages.insert(locktime, packages);
 411                 }
 412
 413                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 414                 let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 415                 for _ in 0..waiting_threshold_conf_len {
 416                         if let Some(val) = MaybeReadable::read(reader)? {
 417                                 onchain_events_awaiting_threshold_conf.push(val);
 418                         }
 419                 }
 420
 421                 read_tlv_fields!(reader, {});
 422
 423                 let mut secp_ctx = Secp256k1::new();
 424                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 425
 426                 Ok(OnchainTxHandler {
 427                         channel_value_satoshis,
 428                         channel_keys_id,
 429                         destination_script,
 430                         holder_commitment,
 431                         prev_holder_commitment,
 432                         signer,
 433                         channel_transaction_parameters: channel_parameters,
 434                         claimable_outpoints,
 435                         locktimed_packages,
 436                         pending_claim_requests,
 437                         onchain_events_awaiting_threshold_conf,
 438                         pending_claim_events: Vec::new(),
 439                         secp_ctx,
 440                 })
 441         }
 442 }
 443
 444 impl<ChannelSigner: EcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 445         pub(crate) fn new(
 446                 channel_value_satoshis: u64, channel_keys_id: [u8; 32], destination_script: ScriptBuf,
 447                 signer: ChannelSigner, channel_parameters: ChannelTransactionParameters,
 448                 holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>
 449         ) -> Self {
 450                 OnchainTxHandler {
 451                         channel_value_satoshis,
 452                         channel_keys_id,
 453                         destination_script,
 454                         holder_commitment,
 455                         prev_holder_commitment: None,
 456                         signer,
 457                         channel_transaction_parameters: channel_parameters,
 458                         pending_claim_requests: new_hash_map(),
 459                         claimable_outpoints: new_hash_map(),
 460                         locktimed_packages: BTreeMap::new(),
 461                         onchain_events_awaiting_threshold_conf: Vec::new(),
 462                         pending_claim_events: Vec::new(),
 463                         secp_ctx,
 464                 }
 465         }
 466
 467         pub(crate) fn get_prev_holder_commitment_to_self_value(&self) -> Option<u64> {
 468                 self.prev_holder_commitment.as_ref().map(|commitment| commitment.to_broadcaster_value_sat())
 469         }
 470
 471         pub(crate) fn get_cur_holder_commitment_to_self_value(&self) -> u64 {
 472                 self.holder_commitment.to_broadcaster_value_sat()
 473         }
 474
 475         pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
 476                 let mut events = Vec::new();
 477                 swap(&mut events, &mut self.pending_claim_events);
 478                 events
 479         }
 480
 481         /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
 482         /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
 483         /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
 484         /// invoking this every 30 seconds, or lower if running in an environment with spotty
 485         /// connections, like on mobile.
 486         pub(super) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Logger>(
 487                 &mut self, current_height: u32, feerate_strategy: FeerateStrategy, broadcaster: &B,
 488                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 489         )
 490         where
 491                 B::Target: BroadcasterInterface,
 492                 F::Target: FeeEstimator,
 493         {
 494                 let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
 495                 for (claim_id, request) in self.pending_claim_requests.iter() {
 496                         let inputs = request.outpoints();
 497                         log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
 498                         bump_requests.push((*claim_id, request.clone()));
 499                 }
 500                 for (claim_id, request) in bump_requests {
 501                         self.generate_claim(current_height, &request, &feerate_strategy, fee_estimator, logger)
 502                                 .map(|(_, new_feerate, claim)| {
 503                                         let mut bumped_feerate = false;
 504                                         if let Some(mut_request) = self.pending_claim_requests.get_mut(&claim_id) {
 505                                                 bumped_feerate = request.previous_feerate() > new_feerate;
 506                                                 mut_request.set_feerate(new_feerate);
 507                                         }
 508                                         match claim {
 509                                                 OnchainClaim::Tx(tx) => {
 510                                                         if tx.is_fully_signed() {
 511                                                                 let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
 512                                                                 log_info!(logger, "{} onchain {}", log_start, log_tx!(tx.0));
 513                                                                 broadcaster.broadcast_transactions(&[&tx.0]);
 514                                                         } else {
 515                                                                 log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", tx.0.txid());
 516                                                         }
 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: Logger>(
 545                 &mut self, cur_height: u32, cached_request: &PackageTemplate, feerate_strategy: &FeerateStrategy,
 546                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 547         ) -> Option<(u32, u64, OnchainClaim)>
 548         where F::Target: FeeEstimator,
 549         {
 550                 let request_outpoints = cached_request.outpoints();
 551                 if request_outpoints.is_empty() {
 552                         // Don't prune pending claiming request yet, we may have to resurrect HTLCs. Untractable
 553                         // packages cannot be aggregated and will never be split, so we cannot end up with an
 554                         // empty claim.
 555                         debug_assert!(cached_request.is_malleable());
 556                         return None;
 557                 }
 558                 // If we've seen transaction inclusion in the chain for all outpoints in our request, we
 559                 // don't need to continue generating more claims. We'll keep tracking the request to fully
 560                 // remove it once it reaches the confirmation threshold, or to generate a new claim if the
 561                 // transaction is reorged out.
 562                 let mut all_inputs_have_confirmed_spend = true;
 563                 for outpoint in request_outpoints.iter() {
 564                         if let Some((request_claim_id, _)) = self.claimable_outpoints.get(*outpoint) {
 565                                 // We check for outpoint spends within claims individually rather than as a set
 566                                 // since requests can have outpoints split off.
 567                                 if !self.onchain_events_awaiting_threshold_conf.iter()
 568                                         .any(|event_entry| if let OnchainEvent::Claim { claim_id } = event_entry.event {
 569                                                 *request_claim_id == claim_id
 570                                         } else {
 571                                                 // The onchain event is not a claim, keep seeking until we find one.
 572                                                 false
 573                                         })
 574                                 {
 575                                         // Either we had no `OnchainEvent::Claim`, or we did but none matched the
 576                                         // outpoint's registered spend.
 577                                         all_inputs_have_confirmed_spend = false;
 578                                 }
 579                         } else {
 580                                 // The request's outpoint spend does not exist yet.
 581                                 all_inputs_have_confirmed_spend = false;
 582                         }
 583                 }
 584                 if all_inputs_have_confirmed_spend {
 585                         return None;
 586                 }
 587
 588                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 589                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 590                 let new_timer = cached_request.get_height_timer(cur_height);
 591                 if cached_request.is_malleable() {
 592                         if cached_request.requires_external_funding() {
 593                                 let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
 594                                         fee_estimator, ConfirmationTarget::OnChainSweep, feerate_strategy,
 595                                 );
 596                                 if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
 597                                         return Some((
 598                                                 new_timer,
 599                                                 target_feerate_sat_per_1000_weight as u64,
 600                                                 OnchainClaim::Event(ClaimEvent::BumpHTLC {
 601                                                         target_feerate_sat_per_1000_weight,
 602                                                         htlcs,
 603                                                         tx_lock_time: LockTime::from_consensus(cached_request.package_locktime(cur_height)),
 604                                                 }),
 605                                         ));
 606                                 } else {
 607                                         return None;
 608                                 }
 609                         }
 610
 611                         let predicted_weight = cached_request.package_weight(&self.destination_script);
 612                         if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
 613                                 predicted_weight, self.destination_script.dust_value().to_sat(),
 614                                 feerate_strategy, fee_estimator, logger,
 615                         ) {
 616                                 assert!(new_feerate != 0);
 617
 618                                 let transaction = cached_request.maybe_finalize_malleable_package(
 619                                         cur_height, self, Amount::from_sat(output_value), self.destination_script.clone(), logger
 620                                 ).unwrap();
 621                                 assert!(predicted_weight >= transaction.0.weight().to_wu());
 622                                 return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
 623                         }
 624                 } else {
 625                         // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
 626                         // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
 627                         // which require external funding.
 628                         let mut inputs = cached_request.inputs();
 629                         debug_assert_eq!(inputs.len(), 1);
 630                         let tx = match cached_request.maybe_finalize_untractable_package(self, logger) {
 631                                 Some(tx) => tx,
 632                                 None => return None,
 633                         };
 634                         if !cached_request.requires_external_funding() {
 635                                 return Some((new_timer, 0, OnchainClaim::Tx(tx)));
 636                         }
 637                         return inputs.find_map(|input| match input {
 638                                 // Commitment inputs with anchors support are the only untractable inputs supported
 639                                 // thus far that require external funding.
 640                                 PackageSolvingData::HolderFundingOutput(output) => {
 641                                         debug_assert_eq!(tx.0.txid(), self.holder_commitment.trust().txid(),
 642                                                 "Holder commitment transaction mismatch");
 643
 644                                         let conf_target = ConfirmationTarget::OnChainSweep;
 645                                         let package_target_feerate_sat_per_1000_weight = cached_request
 646                                                 .compute_package_feerate(fee_estimator, conf_target, feerate_strategy);
 647                                         if let Some(input_amount_sat) = output.funding_amount {
 648                                                 let fee_sat = input_amount_sat - tx.0.output.iter().map(|output| output.value.to_sat()).sum::<u64>();
 649                                                 let commitment_tx_feerate_sat_per_1000_weight =
 650                                                         compute_feerate_sat_per_1000_weight(fee_sat, tx.0.weight().to_wu());
 651                                                 if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
 652                                                         log_debug!(logger, "Pre-signed commitment {} already has feerate {} sat/kW above required {} sat/kW",
 653                                                                 tx.0.txid(), commitment_tx_feerate_sat_per_1000_weight,
 654                                                                 package_target_feerate_sat_per_1000_weight);
 655                                                         return Some((new_timer, 0, OnchainClaim::Tx(tx.clone())));
 656                                                 }
 657                                         }
 658
 659                                         // We'll locate an anchor output we can spend within the commitment transaction.
 660                                         let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
 661                                         match chan_utils::get_anchor_output(&tx.0, funding_pubkey) {
 662                                                 // An anchor output was found, so we should yield a funding event externally.
 663                                                 Some((idx, _)) => {
 664                                                         // TODO: Use a lower confirmation target when both our and the
 665                                                         // counterparty's latest commitment don't have any HTLCs present.
 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.0.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         pub fn abandon_claim(&mut self, outpoint: &BitcoinOutPoint) {
 693                 let claim_id = self.claimable_outpoints.get(outpoint).map(|(claim_id, _)| *claim_id)
 694                         .or_else(|| {
 695                                 self.pending_claim_requests.iter()
 696                                         .find(|(_, claim)| claim.outpoints().iter().any(|claim_outpoint| *claim_outpoint == outpoint))
 697                                         .map(|(claim_id, _)| *claim_id)
 698                         });
 699                 if let Some(claim_id) = claim_id {
 700                         if let Some(claim) = self.pending_claim_requests.remove(&claim_id) {
 701                                 for outpoint in claim.outpoints() {
 702                                         self.claimable_outpoints.remove(outpoint);
 703                                 }
 704                         }
 705                 } else {
 706                         self.locktimed_packages.values_mut().for_each(|claims|
 707                                 claims.retain(|claim| !claim.outpoints().iter().any(|claim_outpoint| *claim_outpoint == outpoint)));
 708                 }
 709         }
 710
 711         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 712         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 713         /// Together with `update_claims_view_from_matched_txn` this used to be named
 714         /// `block_connected`, but it is now also used for claiming an HTLC output if we receive a
 715         /// preimage after force-close.
 716         ///
 717         /// `conf_height` represents the height at which the request was generated. This
 718         /// does not need to equal the current blockchain tip height, which should be provided via
 719         /// `cur_height`, however it must never be higher than `cur_height`.
 720         pub(super) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Logger>(
 721                 &mut self, requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32,
 722                 broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 723         ) where
 724                 B::Target: BroadcasterInterface,
 725                 F::Target: FeeEstimator,
 726         {
 727                 if !requests.is_empty() {
 728                         log_debug!(logger, "Updating claims view at height {} with {} claim requests", cur_height, requests.len());
 729                 }
 730
 731                 let mut preprocessed_requests = Vec::with_capacity(requests.len());
 732                 let mut aggregated_request = None;
 733
 734                 // Try to aggregate outputs if their timelock expiration isn't imminent (package timelock
 735                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 736                 for req in requests {
 737                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 738                         if let Some(_) = self.claimable_outpoints.get(req.outpoints()[0]) {
 739                                 log_info!(logger, "Ignoring second claim for outpoint {}:{}, already registered its claiming request", req.outpoints()[0].txid, req.outpoints()[0].vout);
 740                         } else {
 741                                 let timelocked_equivalent_package = self.locktimed_packages.iter().map(|v| v.1.iter()).flatten()
 742                                         .find(|locked_package| locked_package.outpoints() == req.outpoints());
 743                                 if let Some(package) = timelocked_equivalent_package {
 744                                         log_info!(logger, "Ignoring second claim for outpoint {}:{}, we already have one which we're waiting on a timelock at {} for.",
 745                                                 req.outpoints()[0].txid, req.outpoints()[0].vout, package.package_locktime(cur_height));
 746                                         continue;
 747                                 }
 748
 749                                 let package_locktime = req.package_locktime(cur_height);
 750                                 if package_locktime > cur_height + 1 {
 751                                         log_info!(logger, "Delaying claim of package until its timelock at {} (current height {}), the following outpoints are spent:", package_locktime, cur_height);
 752                                         for outpoint in req.outpoints() {
 753                                                 log_info!(logger, "  Outpoint {}", outpoint);
 754                                         }
 755                                         self.locktimed_packages.entry(package_locktime).or_insert(Vec::new()).push(req);
 756                                         continue;
 757                                 }
 758
 759                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.timelock(), cur_height + CLTV_SHARED_CLAIM_BUFFER);
 760                                 if req.timelock() <= cur_height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable() {
 761                                         // Don't aggregate if outpoint package timelock is soon or marked as non-aggregable
 762                                         preprocessed_requests.push(req);
 763                                 } else if aggregated_request.is_none() {
 764                                         aggregated_request = Some(req);
 765                                 } else {
 766                                         aggregated_request.as_mut().unwrap().merge_package(req);
 767                                 }
 768                         }
 769                 }
 770                 if let Some(req) = aggregated_request {
 771                         preprocessed_requests.push(req);
 772                 }
 773
 774                 // Claim everything up to and including `cur_height`
 775                 let remaining_locked_packages = self.locktimed_packages.split_off(&(cur_height + 1));
 776                 if !self.locktimed_packages.is_empty() {
 777                         log_debug!(logger,
 778                                 "Updating claims view at height {} with {} locked packages available for claim",
 779                                 cur_height,
 780                                 self.locktimed_packages.len());
 781                 }
 782                 for (pop_height, mut entry) in self.locktimed_packages.iter_mut() {
 783                         log_trace!(logger, "Restoring delayed claim of package(s) at their timelock at {}.", pop_height);
 784                         preprocessed_requests.append(&mut entry);
 785                 }
 786                 self.locktimed_packages = remaining_locked_packages;
 787
 788                 // Generate claim transactions and track them to bump if necessary at
 789                 // height timer expiration (i.e in how many blocks we're going to take action).
 790                 for mut req in preprocessed_requests {
 791                         if let Some((new_timer, new_feerate, claim)) = self.generate_claim(
 792                                 cur_height, &req, &FeerateStrategy::ForceBump, &*fee_estimator, &*logger,
 793                         ) {
 794                                 req.set_timer(new_timer);
 795                                 req.set_feerate(new_feerate);
 796                                 // Once a pending claim has an id assigned, it remains fixed until the claim is
 797                                 // satisfied, regardless of whether the claim switches between different variants of
 798                                 // `OnchainClaim`.
 799                                 let claim_id = match claim {
 800                                         OnchainClaim::Tx(tx) => {
 801                                                 if tx.is_fully_signed() {
 802                                                         log_info!(logger, "Broadcasting onchain {}", log_tx!(tx.0));
 803                                                         broadcaster.broadcast_transactions(&[&tx.0]);
 804                                                 } else {
 805                                                         log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", tx.0.txid());
 806                                                 }
 807                                                 ClaimId(tx.0.txid().to_byte_array())
 808                                         },
 809                                         OnchainClaim::Event(claim_event) => {
 810                                                 log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
 811                                                 let claim_id = match claim_event {
 812                                                         ClaimEvent::BumpCommitment { ref commitment_tx, .. } =>
 813                                                                 // For commitment claims, we can just use their txid as it should
 814                                                                 // already be unique.
 815                                                                 ClaimId(commitment_tx.txid().to_byte_array()),
 816                                                         ClaimEvent::BumpHTLC { ref htlcs, .. } => {
 817                                                                 // For HTLC claims, commit to the entire set of HTLC outputs to
 818                                                                 // claim, which will always be unique per request. Once a claim ID
 819                                                                 // is generated, it is assigned and remains unchanged, even if the
 820                                                                 // underlying set of HTLCs changes.
 821                                                                 let mut engine = Sha256::engine();
 822                                                                 for htlc in htlcs {
 823                                                                         engine.input(&htlc.commitment_txid.to_byte_array());
 824                                                                         engine.input(&htlc.htlc.transaction_output_index.unwrap().to_be_bytes());
 825                                                                 }
 826                                                                 ClaimId(Sha256::from_engine(engine).to_byte_array())
 827                                                         },
 828                                                 };
 829                                                 debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
 830                                                 debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == claim_id).count(), 0);
 831                                                 self.pending_claim_events.push((claim_id, claim_event));
 832                                                 claim_id
 833                                         },
 834                                 };
 835                                 // Because fuzzing can cause hash collisions, we can end up with conflicting claim
 836                                 // ids here, so we only assert when not fuzzing.
 837                                 debug_assert!(cfg!(fuzzing) || self.pending_claim_requests.get(&claim_id).is_none());
 838                                 for k in req.outpoints() {
 839                                         log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 840                                         self.claimable_outpoints.insert(k.clone(), (claim_id, conf_height));
 841                                 }
 842                                 self.pending_claim_requests.insert(claim_id, req);
 843                         }
 844                 }
 845         }
 846
 847         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
 848         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
 849         /// Together with `update_claims_view_from_requests` this used to be named `block_connected`,
 850         /// but it is now also used for claiming an HTLC output if we receive a preimage after force-close.
 851         ///
 852         /// `conf_height` represents the height at which the transactions in `txn_matched` were
 853         /// confirmed. This does not need to equal the current blockchain tip height, which should be
 854         /// provided via `cur_height`, however it must never be higher than `cur_height`.
 855         pub(super) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Logger>(
 856                 &mut self, txn_matched: &[&Transaction], conf_height: u32, conf_hash: BlockHash,
 857                 cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
 858         ) where
 859                 B::Target: BroadcasterInterface,
 860                 F::Target: FeeEstimator,
 861         {
 862                 let mut have_logged_intro = false;
 863                 let mut maybe_log_intro = || {
 864                         if !have_logged_intro {
 865                                 log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {}", cur_height, txn_matched.len(), conf_height);
 866                                 have_logged_intro = true;
 867                         }
 868                 };
 869                 let mut bump_candidates = new_hash_map();
 870                 if !txn_matched.is_empty() { maybe_log_intro(); }
 871                 for tx in txn_matched {
 872                         // Scan all input to verify is one of the outpoint spent is of interest for us
 873                         let mut claimed_outputs_material = Vec::new();
 874                         for inp in &tx.input {
 875                                 if let Some((claim_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
 876                                         // If outpoint has claim request pending on it...
 877                                         if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
 878                                                 //... we need to verify equality between transaction outpoints and claim request
 879                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 880                                                 // by us.
 881                                                 let mut are_sets_equal = true;
 882                                                 let mut tx_inputs = tx.input.iter().map(|input| &input.previous_output).collect::<Vec<_>>();
 883                                                 tx_inputs.sort_unstable();
 884                                                 for request_input in request.outpoints() {
 885                                                         if tx_inputs.binary_search(&request_input).is_err() {
 886                                                                 are_sets_equal = false;
 887                                                                 break;
 888                                                         }
 889                                                 }
 890
 891                                                 macro_rules! clean_claim_request_after_safety_delay {
 892                                                         () => {
 893                                                                 let entry = OnchainEventEntry {
 894                                                                         txid: tx.txid(),
 895                                                                         height: conf_height,
 896                                                                         block_hash: Some(conf_hash),
 897                                                                         event: OnchainEvent::Claim { claim_id: *claim_id }
 898                                                                 };
 899                                                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 900                                                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 901                                                                 }
 902                                                         }
 903                                                 }
 904
 905                                                 // If this is our transaction (or our counterparty spent all the outputs
 906                                                 // before we could anyway with same inputs order than us), wait for
 907                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 908                                                 if are_sets_equal {
 909                                                         clean_claim_request_after_safety_delay!();
 910                                                 } else { // If false, generate new claim request with update outpoint set
 911                                                         let mut at_least_one_drop = false;
 912                                                         for input in tx.input.iter() {
 913                                                                 if let Some(package) = request.split_package(&input.previous_output) {
 914                                                                         claimed_outputs_material.push(package);
 915                                                                         at_least_one_drop = true;
 916                                                                 }
 917                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 918                                                                 if request.outpoints().is_empty() {
 919                                                                         clean_claim_request_after_safety_delay!();
 920                                                                 }
 921                                                         }
 922                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 923                                                         if at_least_one_drop {
 924                                                                 bump_candidates.insert(*claim_id, request.clone());
 925                                                                 // If we have any pending claim events for the request being updated
 926                                                                 // that have yet to be consumed, we'll remove them since they will
 927                                                                 // end up producing an invalid transaction by double spending
 928                                                                 // input(s) that already have a confirmed spend. If such spend is
 929                                                                 // reorged out of the chain, then we'll attempt to re-spend the
 930                                                                 // inputs once we see it.
 931                                                                 #[cfg(debug_assertions)] {
 932                                                                         let existing = self.pending_claim_events.iter()
 933                                                                                 .filter(|entry| entry.0 == *claim_id).count();
 934                                                                         assert!(existing == 0 || existing == 1);
 935                                                                 }
 936                                                                 self.pending_claim_events.retain(|entry| entry.0 != *claim_id);
 937                                                         }
 938                                                 }
 939                                                 break; //No need to iterate further, either tx is our or their
 940                                         } else {
 941                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 942                                         }
 943                                 }
 944                         }
 945                         for package in claimed_outputs_material.drain(..) {
 946                                 let entry = OnchainEventEntry {
 947                                         txid: tx.txid(),
 948                                         height: conf_height,
 949                                         block_hash: Some(conf_hash),
 950                                         event: OnchainEvent::ContentiousOutpoint { package },
 951                                 };
 952                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
 953                                         self.onchain_events_awaiting_threshold_conf.push(entry);
 954                                 }
 955                         }
 956                 }
 957
 958                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 959                 let onchain_events_awaiting_threshold_conf =
 960                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
 961                 for entry in onchain_events_awaiting_threshold_conf {
 962                         if entry.has_reached_confirmation_threshold(cur_height) {
 963                                 maybe_log_intro();
 964                                 match entry.event {
 965                                         OnchainEvent::Claim { claim_id } => {
 966                                                 // We may remove a whole set of claim outpoints here, as these one may have
 967                                                 // been aggregated in a single tx and claimed so atomically
 968                                                 if let Some(request) = self.pending_claim_requests.remove(&claim_id) {
 969                                                         for outpoint in request.outpoints() {
 970                                                                 log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
 971                                                                         outpoint, log_bytes!(claim_id.0));
 972                                                                 self.claimable_outpoints.remove(outpoint);
 973                                                         }
 974                                                         #[cfg(debug_assertions)] {
 975                                                                 let num_existing = self.pending_claim_events.iter()
 976                                                                         .filter(|entry| entry.0 == claim_id).count();
 977                                                                 assert!(num_existing == 0 || num_existing == 1);
 978                                                         }
 979                                                         self.pending_claim_events.retain(|(id, _)| *id != claim_id);
 980                                                 }
 981                                         },
 982                                         OnchainEvent::ContentiousOutpoint { package } => {
 983                                                 log_debug!(logger, "Removing claim tracking due to maturation of claim tx for outpoints:");
 984                                                 log_debug!(logger, " {:?}", package.outpoints());
 985                                                 self.claimable_outpoints.remove(package.outpoints()[0]);
 986                                         }
 987                                 }
 988                         } else {
 989                                 self.onchain_events_awaiting_threshold_conf.push(entry);
 990                         }
 991                 }
 992
 993                 // Check if any pending claim request must be rescheduled
 994                 for (claim_id, request) in self.pending_claim_requests.iter() {
 995                         if cur_height >= request.timer() {
 996                                 bump_candidates.insert(*claim_id, request.clone());
 997                         }
 998                 }
 999
1000                 // Build, bump and rebroadcast tx accordingly
1001                 if !bump_candidates.is_empty() {
1002                         maybe_log_intro();
1003                         log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
1004                 }
1005
1006                 for (claim_id, request) in bump_candidates.iter() {
1007                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
1008                                 cur_height, &request, &FeerateStrategy::ForceBump, &*fee_estimator, &*logger,
1009                         ) {
1010                                 match bump_claim {
1011                                         OnchainClaim::Tx(bump_tx) => {
1012                                                 if bump_tx.is_fully_signed() {
1013                                                         log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx.0));
1014                                                         broadcaster.broadcast_transactions(&[&bump_tx.0]);
1015                                                 } else {
1016                                                         log_info!(logger, "Waiting for signature of RBF-bumped unsigned onchain transaction {}",
1017                                                                 bump_tx.0.txid());
1018                                                 }
1019                                         },
1020                                         OnchainClaim::Event(claim_event) => {
1021                                                 log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
1022                                                 #[cfg(debug_assertions)] {
1023                                                         let num_existing = self.pending_claim_events.iter().
1024                                                                 filter(|entry| entry.0 == *claim_id).count();
1025                                                         assert!(num_existing == 0 || num_existing == 1);
1026                                                 }
1027                                                 self.pending_claim_events.retain(|event| event.0 != *claim_id);
1028                                                 self.pending_claim_events.push((*claim_id, claim_event));
1029                                         },
1030                                 }
1031                                 if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
1032                                         request.set_timer(new_timer);
1033                                         request.set_feerate(new_feerate);
1034                                 }
1035                         }
1036                 }
1037         }
1038
1039         pub(super) fn transaction_unconfirmed<B: Deref, F: Deref, L: Logger>(
1040                 &mut self,
1041                 txid: &Txid,
1042                 broadcaster: B,
1043                 fee_estimator: &LowerBoundedFeeEstimator<F>,
1044                 logger: &L,
1045         ) where
1046                 B::Target: BroadcasterInterface,
1047                 F::Target: FeeEstimator,
1048         {
1049                 let mut height = None;
1050                 for entry in self.onchain_events_awaiting_threshold_conf.iter() {
1051                         if entry.txid == *txid {
1052                                 height = Some(entry.height);
1053                                 break;
1054                         }
1055                 }
1056
1057                 if let Some(height) = height {
1058                         self.block_disconnected(height, broadcaster, fee_estimator, logger);
1059                 }
1060         }
1061
1062         pub(super) fn block_disconnected<B: Deref, F: Deref, L: Logger>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L)
1063                 where B::Target: BroadcasterInterface,
1064                         F::Target: FeeEstimator,
1065         {
1066                 let mut bump_candidates = new_hash_map();
1067                 let onchain_events_awaiting_threshold_conf =
1068                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
1069                 for entry in onchain_events_awaiting_threshold_conf {
1070                         if entry.height >= height {
1071                                 //- our claim tx on a commitment tx output
1072                                 //- resurect outpoint back in its claimable set and regenerate tx
1073                                 match entry.event {
1074                                         OnchainEvent::ContentiousOutpoint { package } => {
1075                                                 if let Some(pending_claim) = self.claimable_outpoints.get(package.outpoints()[0]) {
1076                                                         if let Some(request) = self.pending_claim_requests.get_mut(&pending_claim.0) {
1077                                                                 request.merge_package(package);
1078                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
1079                                                                 // resurrected only one bump claim tx is going to be broadcast
1080                                                                 bump_candidates.insert(pending_claim.clone(), request.clone());
1081                                                         }
1082                                                 }
1083                                         },
1084                                         _ => {},
1085                                 }
1086                         } else {
1087                                 self.onchain_events_awaiting_threshold_conf.push(entry);
1088                         }
1089                 }
1090                 for ((_claim_id, _), ref mut request) in bump_candidates.iter_mut() {
1091                         // `height` is the height being disconnected, so our `current_height` is 1 lower.
1092                         let current_height = height - 1;
1093                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
1094                                 current_height, &request, &FeerateStrategy::ForceBump, fee_estimator, logger
1095                         ) {
1096                                 request.set_timer(new_timer);
1097                                 request.set_feerate(new_feerate);
1098                                 match bump_claim {
1099                                         OnchainClaim::Tx(bump_tx) => {
1100                                                 if bump_tx.is_fully_signed() {
1101                                                         log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx.0));
1102                                                         broadcaster.broadcast_transactions(&[&bump_tx.0]);
1103                                                 } else {
1104                                                         log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", bump_tx.0.txid());
1105                                                 }
1106                                         },
1107                                         OnchainClaim::Event(claim_event) => {
1108                                                 log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
1109                                                 #[cfg(debug_assertions)] {
1110                                                         let num_existing = self.pending_claim_events.iter()
1111                                                                 .filter(|entry| entry.0 == *_claim_id).count();
1112                                                         assert!(num_existing == 0 || num_existing == 1);
1113                                                 }
1114                                                 self.pending_claim_events.retain(|event| event.0 != *_claim_id);
1115                                                 self.pending_claim_events.push((*_claim_id, claim_event));
1116                                         },
1117                                 }
1118                         }
1119                 }
1120                 for (ancestor_claim_txid, request) in bump_candidates.drain() {
1121                         self.pending_claim_requests.insert(ancestor_claim_txid.0, request);
1122                 }
1123                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
1124                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
1125                 let mut remove_request = Vec::new();
1126                 self.claimable_outpoints.retain(|_, ref v|
1127                         if v.1 >= height {
1128                         remove_request.push(v.0.clone());
1129                         false
1130                         } else { true });
1131                 for req in remove_request {
1132                         self.pending_claim_requests.remove(&req);
1133                 }
1134         }
1135
1136         pub(crate) fn is_output_spend_pending(&self, outpoint: &BitcoinOutPoint) -> bool {
1137                 self.claimable_outpoints.get(outpoint).is_some()
1138         }
1139
1140         pub(crate) fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
1141                 let mut txids: Vec<(Txid, u32, Option<BlockHash>)> = self.onchain_events_awaiting_threshold_conf
1142                         .iter()
1143                         .map(|entry| (entry.txid, entry.height, entry.block_hash))
1144                         .collect();
1145                 txids.sort_unstable_by(|a, b| a.0.cmp(&b.0).then(b.1.cmp(&a.1)));
1146                 txids.dedup_by_key(|(txid, _, _)| *txid);
1147                 txids
1148         }
1149
1150         pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
1151                 self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
1152         }
1153
1154         pub(crate) fn get_unsigned_holder_commitment_tx(&self) -> &Transaction {
1155                 &self.holder_commitment.trust().built_transaction().transaction
1156         }
1157
1158         pub(crate) fn get_maybe_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> MaybeSignedTransaction {
1159                 let tx = self.signer.sign_holder_commitment(&self.holder_commitment, &self.secp_ctx)
1160                         .map(|sig| self.holder_commitment.add_holder_sig(funding_redeemscript, sig))
1161                         .unwrap_or_else(|_| self.get_unsigned_holder_commitment_tx().clone());
1162                 MaybeSignedTransaction(tx)
1163         }
1164
1165         #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
1166         pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1167                 let sig = self.signer.unsafe_sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
1168                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1169         }
1170
1171         pub(crate) fn get_maybe_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<MaybeSignedTransaction> {
1172                 let get_signed_htlc_tx = |holder_commitment: &HolderCommitmentTransaction| {
1173                         let trusted_tx = holder_commitment.trust();
1174                         if trusted_tx.txid() != outp.txid {
1175                                 return None;
1176                         }
1177                         let (htlc_idx, htlc) = trusted_tx.htlcs().iter().enumerate()
1178                                 .find(|(_, htlc)| htlc.transaction_output_index.unwrap() == outp.vout)
1179                                 .unwrap();
1180                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1181                         let mut htlc_tx = trusted_tx.build_unsigned_htlc_tx(
1182                                 &self.channel_transaction_parameters.as_holder_broadcastable(), htlc_idx, preimage,
1183                         );
1184
1185                         let htlc_descriptor = HTLCDescriptor {
1186                                 channel_derivation_parameters: ChannelDerivationParameters {
1187                                         value_satoshis: self.channel_value_satoshis,
1188                                         keys_id: self.channel_keys_id,
1189                                         transaction_parameters: self.channel_transaction_parameters.clone(),
1190                                 },
1191                                 commitment_txid: trusted_tx.txid(),
1192                                 per_commitment_number: trusted_tx.commitment_number(),
1193                                 per_commitment_point: trusted_tx.per_commitment_point(),
1194                                 feerate_per_kw: trusted_tx.feerate_per_kw(),
1195                                 htlc: htlc.clone(),
1196                                 preimage: preimage.clone(),
1197                                 counterparty_sig: counterparty_htlc_sig.clone(),
1198                         };
1199                         if let Ok(htlc_sig) = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx) {
1200                                 htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness(
1201                                         htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage,
1202                                 );
1203                         }
1204                         Some(MaybeSignedTransaction(htlc_tx))
1205                 };
1206
1207                 // Check if the HTLC spends from the current holder commitment first, or the previous.
1208                 get_signed_htlc_tx(&self.holder_commitment)
1209                         .or_else(|| self.prev_holder_commitment.as_ref().and_then(|prev_holder_commitment| get_signed_htlc_tx(prev_holder_commitment)))
1210         }
1211
1212         pub(crate) fn generate_external_htlc_claim(
1213                 &self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
1214         ) -> Option<ExternalHTLCClaim> {
1215                 let find_htlc = |holder_commitment: &HolderCommitmentTransaction| -> Option<ExternalHTLCClaim> {
1216                         let trusted_tx = holder_commitment.trust();
1217                         if outp.txid != trusted_tx.txid() {
1218                                 return None;
1219                         }
1220                         trusted_tx.htlcs().iter().enumerate()
1221                                 .find(|(_, htlc)| if let Some(output_index) = htlc.transaction_output_index {
1222                                         output_index == outp.vout
1223                                 } else {
1224                                         false
1225                                 })
1226                                 .map(|(htlc_idx, htlc)| {
1227                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1228                                         ExternalHTLCClaim {
1229                                                 commitment_txid: trusted_tx.txid(),
1230                                                 per_commitment_number: trusted_tx.commitment_number(),
1231                                                 htlc: htlc.clone(),
1232                                                 preimage: *preimage,
1233                                                 counterparty_sig: counterparty_htlc_sig,
1234                                         }
1235                                 })
1236                 };
1237                 // Check if the HTLC spends from the current holder commitment or the previous one otherwise.
1238                 find_htlc(&self.holder_commitment)
1239                         .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
1240         }
1241
1242         pub(crate) fn channel_type_features(&self) -> &ChannelTypeFeatures {
1243                 &self.channel_transaction_parameters.channel_type_features
1244         }
1245 }