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Don't sign holder HTLCs along with holder commitments
[rust-lightning] / 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         prev_holder_commitment: Option<HolderCommitmentTransaction>,
224
225         pub(super) signer: ChannelSigner,
226         pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
227
228         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
229         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
230         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
231         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
232         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
233         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
234         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
235         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
236         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
237         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
238         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
239         #[cfg(test)] // Used in functional_test to verify sanitization
240         pub(crate) pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
241         #[cfg(not(test))]
242         pending_claim_requests: HashMap<ClaimId, PackageTemplate>,
243
244         // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
245         // essentially acts as an insertion-ordered `HashMap` â€“ there should only ever be one occurrence
246         // of a `ClaimId`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
247         // a new block has been connected, resulting in a new claim, the previous will be replaced with
248         // the new.
249         //
250         // These external events may be generated in the following cases:
251         //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
252         //      - A block being connected/disconnected
253         //      - Learning the preimage for an HTLC we can claim onchain
254         pending_claim_events: Vec<(ClaimId, ClaimEvent)>,
255
256         // Used to link outpoints claimed in a connected block to a pending claim request. The keys
257         // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
258         // claim. The values track the pending claim request identifier and the initial confirmation
259         // block height, and are immutable until the outpoint has enough confirmations to meet our
260         // [`ANTI_REORG_DELAY`]. The initial confirmation block height is used to remove the entry if
261         // the block gets disconnected.
262         #[cfg(test)] // Used in functional_test to verify sanitization
263         pub claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
264         #[cfg(not(test))]
265         claimable_outpoints: HashMap<BitcoinOutPoint, (ClaimId, u32)>,
266
267         locktimed_packages: BTreeMap<u32, Vec<PackageTemplate>>,
268
269         onchain_events_awaiting_threshold_conf: Vec<OnchainEventEntry>,
270
271         pub(super) secp_ctx: Secp256k1<secp256k1::All>,
272 }
273
274 impl<ChannelSigner: WriteableEcdsaChannelSigner> PartialEq for OnchainTxHandler<ChannelSigner> {
275         fn eq(&self, other: &Self) -> bool {
276                 // `signer`, `secp_ctx`, and `pending_claim_events` are excluded on purpose.
277                 self.channel_value_satoshis == other.channel_value_satoshis &&
278                         self.channel_keys_id == other.channel_keys_id &&
279                         self.destination_script == other.destination_script &&
280                         self.holder_commitment == other.holder_commitment &&
281                         self.prev_holder_commitment == other.prev_holder_commitment &&
282                         self.channel_transaction_parameters == other.channel_transaction_parameters &&
283                         self.pending_claim_requests == other.pending_claim_requests &&
284                         self.claimable_outpoints == other.claimable_outpoints &&
285                         self.locktimed_packages == other.locktimed_packages &&
286                         self.onchain_events_awaiting_threshold_conf == other.onchain_events_awaiting_threshold_conf
287         }
288 }
289
290 const SERIALIZATION_VERSION: u8 = 1;
291 const MIN_SERIALIZATION_VERSION: u8 = 1;
292
293 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
294         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
295                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
296
297                 self.destination_script.write(writer)?;
298                 self.holder_commitment.write(writer)?;
299                 None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // holder_htlc_sigs
300                 self.prev_holder_commitment.write(writer)?;
301                 None::<Option<Vec<Option<(usize, Signature)>>>>.write(writer)?; // prev_holder_htlc_sigs
302
303                 self.channel_transaction_parameters.write(writer)?;
304
305                 let mut key_data = VecWriter(Vec::new());
306                 self.signer.write(&mut key_data)?;
307                 assert!(key_data.0.len() < core::usize::MAX);
308                 assert!(key_data.0.len() < core::u32::MAX as usize);
309                 (key_data.0.len() as u32).write(writer)?;
310                 writer.write_all(&key_data.0[..])?;
311
312                 writer.write_all(&(self.pending_claim_requests.len() as u64).to_be_bytes())?;
313                 for (ref ancestor_claim_txid, request) in self.pending_claim_requests.iter() {
314                         ancestor_claim_txid.write(writer)?;
315                         request.write(writer)?;
316                 }
317
318                 writer.write_all(&(self.claimable_outpoints.len() as u64).to_be_bytes())?;
319                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
320                         outp.write(writer)?;
321                         claim_and_height.0.write(writer)?;
322                         claim_and_height.1.write(writer)?;
323                 }
324
325                 writer.write_all(&(self.locktimed_packages.len() as u64).to_be_bytes())?;
326                 for (ref locktime, ref packages) in self.locktimed_packages.iter() {
327                         locktime.write(writer)?;
328                         writer.write_all(&(packages.len() as u64).to_be_bytes())?;
329                         for ref package in packages.iter() {
330                                 package.write(writer)?;
331                         }
332                 }
333
334                 writer.write_all(&(self.onchain_events_awaiting_threshold_conf.len() as u64).to_be_bytes())?;
335                 for ref entry in self.onchain_events_awaiting_threshold_conf.iter() {
336                         entry.write(writer)?;
337                 }
338
339                 write_tlv_fields!(writer, {});
340                 Ok(())
341         }
342 }
343
344 impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP, u64, [u8; 32])> for OnchainTxHandler<SP::Signer> {
345         fn read<R: io::Read>(reader: &mut R, args: (&'a ES, &'b SP, u64, [u8; 32])) -> Result<Self, DecodeError> {
346                 let entropy_source = args.0;
347                 let signer_provider = args.1;
348                 let channel_value_satoshis = args.2;
349                 let channel_keys_id = args.3;
350
351                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
352
353                 let destination_script = Readable::read(reader)?;
354
355                 let holder_commitment = Readable::read(reader)?;
356                 let _holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
357                 let prev_holder_commitment = Readable::read(reader)?;
358                 let _prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>> = Readable::read(reader)?;
359
360                 let channel_parameters = Readable::read(reader)?;
361
362                 // Read the serialized signer bytes, but don't deserialize them, as we'll obtain our signer
363                 // by re-deriving the private key material.
364                 let keys_len: u32 = Readable::read(reader)?;
365                 let mut bytes_read = 0;
366                 while bytes_read != keys_len as usize {
367                         // Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
368                         let mut data = [0; 1024];
369                         let bytes_to_read = cmp::min(1024, keys_len as usize - bytes_read);
370                         let read_slice = &mut data[0..bytes_to_read];
371                         reader.read_exact(read_slice)?;
372                         bytes_read += bytes_to_read;
373                 }
374
375                 let mut signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
376                 signer.provide_channel_parameters(&channel_parameters);
377
378                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
379                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
380                 for _ in 0..pending_claim_requests_len {
381                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
382                 }
383
384                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
385                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
386                 for _ in 0..claimable_outpoints_len {
387                         let outpoint = Readable::read(reader)?;
388                         let ancestor_claim_txid = Readable::read(reader)?;
389                         let height = Readable::read(reader)?;
390                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
391                 }
392
393                 let locktimed_packages_len: u64 = Readable::read(reader)?;
394                 let mut locktimed_packages = BTreeMap::new();
395                 for _ in 0..locktimed_packages_len {
396                         let locktime = Readable::read(reader)?;
397                         let packages_len: u64 = Readable::read(reader)?;
398                         let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
399                         for _ in 0..packages_len {
400                                 packages.push(Readable::read(reader)?);
401                         }
402                         locktimed_packages.insert(locktime, packages);
403                 }
404
405                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
406                 let mut onchain_events_awaiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
407                 for _ in 0..waiting_threshold_conf_len {
408                         if let Some(val) = MaybeReadable::read(reader)? {
409                                 onchain_events_awaiting_threshold_conf.push(val);
410                         }
411                 }
412
413                 read_tlv_fields!(reader, {});
414
415                 let mut secp_ctx = Secp256k1::new();
416                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
417
418                 Ok(OnchainTxHandler {
419                         channel_value_satoshis,
420                         channel_keys_id,
421                         destination_script,
422                         holder_commitment,
423                         prev_holder_commitment,
424                         signer,
425                         channel_transaction_parameters: channel_parameters,
426                         claimable_outpoints,
427                         locktimed_packages,
428                         pending_claim_requests,
429                         onchain_events_awaiting_threshold_conf,
430                         pending_claim_events: Vec::new(),
431                         secp_ctx,
432                 })
433         }
434 }
435
436 impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
437         pub(crate) fn new(
438                 channel_value_satoshis: u64, channel_keys_id: [u8; 32], destination_script: Script,
439                 signer: ChannelSigner, channel_parameters: ChannelTransactionParameters,
440                 holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>
441         ) -> Self {
442                 OnchainTxHandler {
443                         channel_value_satoshis,
444                         channel_keys_id,
445                         destination_script,
446                         holder_commitment,
447                         prev_holder_commitment: None,
448                         signer,
449                         channel_transaction_parameters: channel_parameters,
450                         pending_claim_requests: HashMap::new(),
451                         claimable_outpoints: HashMap::new(),
452                         locktimed_packages: BTreeMap::new(),
453                         onchain_events_awaiting_threshold_conf: Vec::new(),
454                         pending_claim_events: Vec::new(),
455                         secp_ctx,
456                 }
457         }
458
459         pub(crate) fn get_prev_holder_commitment_to_self_value(&self) -> Option<u64> {
460                 self.prev_holder_commitment.as_ref().map(|commitment| commitment.to_broadcaster_value_sat())
461         }
462
463         pub(crate) fn get_cur_holder_commitment_to_self_value(&self) -> u64 {
464                 self.holder_commitment.to_broadcaster_value_sat()
465         }
466
467         pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<(ClaimId, ClaimEvent)> {
468                 let mut events = Vec::new();
469                 swap(&mut events, &mut self.pending_claim_events);
470                 events
471         }
472
473         /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
474         /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
475         /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
476         /// invoking this every 30 seconds, or lower if running in an environment with spotty
477         /// connections, like on mobile.
478         pub(crate) fn rebroadcast_pending_claims<B: Deref, F: Deref, L: Deref>(
479                 &mut self, current_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>,
480                 logger: &L,
481         )
482         where
483                 B::Target: BroadcasterInterface,
484                 F::Target: FeeEstimator,
485                 L::Target: Logger,
486         {
487                 let mut bump_requests = Vec::with_capacity(self.pending_claim_requests.len());
488                 for (claim_id, request) in self.pending_claim_requests.iter() {
489                         let inputs = request.outpoints();
490                         log_info!(logger, "Triggering rebroadcast/fee-bump for request with inputs {:?}", inputs);
491                         bump_requests.push((*claim_id, request.clone()));
492                 }
493                 for (claim_id, request) in bump_requests {
494                         self.generate_claim(current_height, &request, false /* force_feerate_bump */, fee_estimator, logger)
495                                 .map(|(_, new_feerate, claim)| {
496                                         let mut bumped_feerate = false;
497                                         if let Some(mut_request) = self.pending_claim_requests.get_mut(&claim_id) {
498                                                 bumped_feerate = request.previous_feerate() > new_feerate;
499                                                 mut_request.set_feerate(new_feerate);
500                                         }
501                                         match claim {
502                                                 OnchainClaim::Tx(tx) => {
503                                                         let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" };
504                                                         log_info!(logger, "{} onchain {}", log_start, log_tx!(tx));
505                                                         broadcaster.broadcast_transactions(&[&tx]);
506                                                 },
507                                                 OnchainClaim::Event(event) => {
508                                                         let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" };
509                                                         log_info!(logger, "{} onchain event to spend inputs {:?}", log_start,
510                                                                 request.outpoints());
511                                                         #[cfg(debug_assertions)] {
512                                                                 debug_assert!(request.requires_external_funding());
513                                                                 let num_existing = self.pending_claim_events.iter()
514                                                                         .filter(|entry| entry.0 == claim_id).count();
515                                                                 assert!(num_existing == 0 || num_existing == 1);
516                                                         }
517                                                         self.pending_claim_events.retain(|event| event.0 != claim_id);
518                                                         self.pending_claim_events.push((claim_id, event));
519                                                 }
520                                         }
521                                 });
522                 }
523         }
524
525         /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
526         /// onchain) lays on the assumption of claim transactions getting confirmed before timelock
527         /// expiration (CSV or CLTV following cases). In case of high-fee spikes, claim tx may get stuck
528         /// in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or
529         /// Child-Pay-For-Parent.
530         ///
531         /// Panics if there are signing errors, because signing operations in reaction to on-chain
532         /// events are not expected to fail, and if they do, we may lose funds.
533         fn generate_claim<F: Deref, L: Deref>(
534                 &mut self, cur_height: u32, cached_request: &PackageTemplate, force_feerate_bump: bool,
535                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
536         ) -> Option<(u32, u64, OnchainClaim)>
537         where
538                 F::Target: FeeEstimator,
539                 L::Target: Logger,
540         {
541                 let request_outpoints = cached_request.outpoints();
542                 if request_outpoints.is_empty() {
543                         // Don't prune pending claiming request yet, we may have to resurrect HTLCs. Untractable
544                         // packages cannot be aggregated and will never be split, so we cannot end up with an
545                         // empty claim.
546                         debug_assert!(cached_request.is_malleable());
547                         return None;
548                 }
549                 // If we've seen transaction inclusion in the chain for all outpoints in our request, we
550                 // don't need to continue generating more claims. We'll keep tracking the request to fully
551                 // remove it once it reaches the confirmation threshold, or to generate a new claim if the
552                 // transaction is reorged out.
553                 let mut all_inputs_have_confirmed_spend = true;
554                 for outpoint in request_outpoints.iter() {
555                         if let Some((request_claim_id, _)) = self.claimable_outpoints.get(*outpoint) {
556                                 // We check for outpoint spends within claims individually rather than as a set
557                                 // since requests can have outpoints split off.
558                                 if !self.onchain_events_awaiting_threshold_conf.iter()
559                                         .any(|event_entry| if let OnchainEvent::Claim { claim_id } = event_entry.event {
560                                                 *request_claim_id == claim_id
561                                         } else {
562                                                 // The onchain event is not a claim, keep seeking until we find one.
563                                                 false
564                                         })
565                                 {
566                                         // Either we had no `OnchainEvent::Claim`, or we did but none matched the
567                                         // outpoint's registered spend.
568                                         all_inputs_have_confirmed_spend = false;
569                                 }
570                         } else {
571                                 // The request's outpoint spend does not exist yet.
572                                 all_inputs_have_confirmed_spend = false;
573                         }
574                 }
575                 if all_inputs_have_confirmed_spend {
576                         return None;
577                 }
578
579                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
580                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
581                 let new_timer = cached_request.get_height_timer(cur_height);
582                 if cached_request.is_malleable() {
583                         if cached_request.requires_external_funding() {
584                                 let target_feerate_sat_per_1000_weight = cached_request.compute_package_feerate(
585                                         fee_estimator, ConfirmationTarget::HighPriority, force_feerate_bump
586                                 );
587                                 if let Some(htlcs) = cached_request.construct_malleable_package_with_external_funding(self) {
588                                         return Some((
589                                                 new_timer,
590                                                 target_feerate_sat_per_1000_weight as u64,
591                                                 OnchainClaim::Event(ClaimEvent::BumpHTLC {
592                                                         target_feerate_sat_per_1000_weight,
593                                                         htlcs,
594                                                         tx_lock_time: PackedLockTime(cached_request.package_locktime(cur_height)),
595                                                 }),
596                                         ));
597                                 } else {
598                                         return None;
599                                 }
600                         }
601
602                         let predicted_weight = cached_request.package_weight(&self.destination_script);
603                         if let Some((output_value, new_feerate)) = cached_request.compute_package_output(
604                                 predicted_weight, self.destination_script.dust_value().to_sat(),
605                                 force_feerate_bump, fee_estimator, logger,
606                         ) {
607                                 assert!(new_feerate != 0);
608
609                                 let transaction = cached_request.finalize_malleable_package(
610                                         cur_height, self, output_value, self.destination_script.clone(), logger
611                                 ).unwrap();
612                                 log_trace!(logger, "...with timer {} and feerate {}", new_timer, new_feerate);
613                                 assert!(predicted_weight >= transaction.weight());
614                                 return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction)));
615                         }
616                 } else {
617                         // Untractable packages cannot have their fees bumped through Replace-By-Fee. Some
618                         // packages may support fee bumping through Child-Pays-For-Parent, indicated by those
619                         // which require external funding.
620                         let mut inputs = cached_request.inputs();
621                         debug_assert_eq!(inputs.len(), 1);
622                         let tx = match cached_request.finalize_untractable_package(self, logger) {
623                                 Some(tx) => tx,
624                                 None => return None,
625                         };
626                         if !cached_request.requires_external_funding() {
627                                 return Some((new_timer, 0, OnchainClaim::Tx(tx)));
628                         }
629                         return inputs.find_map(|input| match input {
630                                 // Commitment inputs with anchors support are the only untractable inputs supported
631                                 // thus far that require external funding.
632                                 PackageSolvingData::HolderFundingOutput(output) => {
633                                         debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(),
634                                                 "Holder commitment transaction mismatch");
635
636                                         let conf_target = ConfirmationTarget::HighPriority;
637                                         let package_target_feerate_sat_per_1000_weight = cached_request
638                                                 .compute_package_feerate(fee_estimator, conf_target, force_feerate_bump);
639                                         if let Some(input_amount_sat) = output.funding_amount {
640                                                 let fee_sat = input_amount_sat - tx.output.iter().map(|output| output.value).sum::<u64>();
641                                                 let commitment_tx_feerate_sat_per_1000_weight =
642                                                         compute_feerate_sat_per_1000_weight(fee_sat, tx.weight() as u64);
643                                                 if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
644                                                         log_debug!(logger, "Pre-signed {} already has feerate {} sat/kW above required {} sat/kW",
645                                                                 log_tx!(tx), commitment_tx_feerate_sat_per_1000_weight,
646                                                                 package_target_feerate_sat_per_1000_weight);
647                                                         return Some((new_timer, 0, OnchainClaim::Tx(tx.clone())));
648                                                 }
649                                         }
650
651                                         // We'll locate an anchor output we can spend within the commitment transaction.
652                                         let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey;
653                                         match chan_utils::get_anchor_output(&tx, funding_pubkey) {
654                                                 // An anchor output was found, so we should yield a funding event externally.
655                                                 Some((idx, _)) => {
656                                                         // TODO: Use a lower confirmation target when both our and the
657                                                         // counterparty's latest commitment don't have any HTLCs present.
658                                                         Some((
659                                                                 new_timer,
660                                                                 package_target_feerate_sat_per_1000_weight as u64,
661                                                                 OnchainClaim::Event(ClaimEvent::BumpCommitment {
662                                                                         package_target_feerate_sat_per_1000_weight,
663                                                                         commitment_tx: tx.clone(),
664                                                                         anchor_output_idx: idx,
665                                                                 }),
666                                                         ))
667                                                 },
668                                                 // An anchor output was not found. There's nothing we can do other than
669                                                 // attempt to broadcast the transaction with its current fee rate and hope
670                                                 // it confirms. This is essentially the same behavior as a commitment
671                                                 // transaction without anchor outputs.
672                                                 None => Some((new_timer, 0, OnchainClaim::Tx(tx.clone()))),
673                                         }
674                                 },
675                                 _ => {
676                                         debug_assert!(false, "Only HolderFundingOutput inputs should be untractable and require external funding");
677                                         None
678                                 },
679                         })
680                 }
681                 None
682         }
683
684         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
685         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
686         /// Together with `update_claims_view_from_matched_txn` this used to be named
687         /// `block_connected`, but it is now also used for claiming an HTLC output if we receive a
688         /// preimage after force-close.
689         ///
690         /// `conf_height` represents the height at which the request was generated. This
691         /// does not need to equal the current blockchain tip height, which should be provided via
692         /// `cur_height`, however it must never be higher than `cur_height`.
693         pub(crate) fn update_claims_view_from_requests<B: Deref, F: Deref, L: Deref>(
694                 &mut self, requests: Vec<PackageTemplate>, conf_height: u32, cur_height: u32,
695                 broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
696         ) where
697                 B::Target: BroadcasterInterface,
698                 F::Target: FeeEstimator,
699                 L::Target: Logger,
700         {
701                 log_debug!(logger, "Updating claims view at height {} with {} claim requests", cur_height, requests.len());
702                 let mut preprocessed_requests = Vec::with_capacity(requests.len());
703                 let mut aggregated_request = None;
704
705                 // Try to aggregate outputs if their timelock expiration isn't imminent (package timelock
706                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
707                 for req in requests {
708                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
709                         if let Some(_) = self.claimable_outpoints.get(req.outpoints()[0]) {
710                                 log_info!(logger, "Ignoring second claim for outpoint {}:{}, already registered its claiming request", req.outpoints()[0].txid, req.outpoints()[0].vout);
711                         } else {
712                                 let timelocked_equivalent_package = self.locktimed_packages.iter().map(|v| v.1.iter()).flatten()
713                                         .find(|locked_package| locked_package.outpoints() == req.outpoints());
714                                 if let Some(package) = timelocked_equivalent_package {
715                                         log_info!(logger, "Ignoring second claim for outpoint {}:{}, we already have one which we're waiting on a timelock at {} for.",
716                                                 req.outpoints()[0].txid, req.outpoints()[0].vout, package.package_locktime(cur_height));
717                                         continue;
718                                 }
719
720                                 let package_locktime = req.package_locktime(cur_height);
721                                 if package_locktime > cur_height + 1 {
722                                         log_info!(logger, "Delaying claim of package until its timelock at {} (current height {}), the following outpoints are spent:", package_locktime, cur_height);
723                                         for outpoint in req.outpoints() {
724                                                 log_info!(logger, "  Outpoint {}", outpoint);
725                                         }
726                                         self.locktimed_packages.entry(package_locktime).or_insert(Vec::new()).push(req);
727                                         continue;
728                                 }
729
730                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.timelock(), cur_height + CLTV_SHARED_CLAIM_BUFFER);
731                                 if req.timelock() <= cur_height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable() {
732                                         // Don't aggregate if outpoint package timelock is soon or marked as non-aggregable
733                                         preprocessed_requests.push(req);
734                                 } else if aggregated_request.is_none() {
735                                         aggregated_request = Some(req);
736                                 } else {
737                                         aggregated_request.as_mut().unwrap().merge_package(req);
738                                 }
739                         }
740                 }
741                 if let Some(req) = aggregated_request {
742                         preprocessed_requests.push(req);
743                 }
744
745                 // Claim everything up to and including `cur_height`
746                 let remaining_locked_packages = self.locktimed_packages.split_off(&(cur_height + 1));
747                 for (pop_height, mut entry) in self.locktimed_packages.iter_mut() {
748                         log_trace!(logger, "Restoring delayed claim of package(s) at their timelock at {}.", pop_height);
749                         preprocessed_requests.append(&mut entry);
750                 }
751                 self.locktimed_packages = remaining_locked_packages;
752
753                 // Generate claim transactions and track them to bump if necessary at
754                 // height timer expiration (i.e in how many blocks we're going to take action).
755                 for mut req in preprocessed_requests {
756                         if let Some((new_timer, new_feerate, claim)) = self.generate_claim(
757                                 cur_height, &req, true /* force_feerate_bump */, &*fee_estimator, &*logger,
758                         ) {
759                                 req.set_timer(new_timer);
760                                 req.set_feerate(new_feerate);
761                                 // Once a pending claim has an id assigned, it remains fixed until the claim is
762                                 // satisfied, regardless of whether the claim switches between different variants of
763                                 // `OnchainClaim`.
764                                 let claim_id = match claim {
765                                         OnchainClaim::Tx(tx) => {
766                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(tx));
767                                                 broadcaster.broadcast_transactions(&[&tx]);
768                                                 ClaimId(tx.txid().into_inner())
769                                         },
770                                         OnchainClaim::Event(claim_event) => {
771                                                 log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints());
772                                                 let claim_id = match claim_event {
773                                                         ClaimEvent::BumpCommitment { ref commitment_tx, .. } =>
774                                                                 // For commitment claims, we can just use their txid as it should
775                                                                 // already be unique.
776                                                                 ClaimId(commitment_tx.txid().into_inner()),
777                                                         ClaimEvent::BumpHTLC { ref htlcs, .. } => {
778                                                                 // For HTLC claims, commit to the entire set of HTLC outputs to
779                                                                 // claim, which will always be unique per request. Once a claim ID
780                                                                 // is generated, it is assigned and remains unchanged, even if the
781                                                                 // underlying set of HTLCs changes.
782                                                                 let mut engine = Sha256::engine();
783                                                                 for htlc in htlcs {
784                                                                         engine.input(&htlc.commitment_txid.into_inner());
785                                                                         engine.input(&htlc.htlc.transaction_output_index.unwrap().to_be_bytes());
786                                                                 }
787                                                                 ClaimId(Sha256::from_engine(engine).into_inner())
788                                                         },
789                                                 };
790                                                 debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
791                                                 debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == claim_id).count(), 0);
792                                                 self.pending_claim_events.push((claim_id, claim_event));
793                                                 claim_id
794                                         },
795                                 };
796                                 debug_assert!(self.pending_claim_requests.get(&claim_id).is_none());
797                                 for k in req.outpoints() {
798                                         log_info!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
799                                         self.claimable_outpoints.insert(k.clone(), (claim_id, conf_height));
800                                 }
801                                 self.pending_claim_requests.insert(claim_id, req);
802                         }
803                 }
804         }
805
806         /// Upon channelmonitor.block_connected(..) or upon provision of a preimage on the forward link
807         /// for this channel, provide new relevant on-chain transactions and/or new claim requests.
808         /// Together with `update_claims_view_from_requests` this used to be named `block_connected`,
809         /// but it is now also used for claiming an HTLC output if we receive a preimage after force-close.
810         ///
811         /// `conf_height` represents the height at which the transactions in `txn_matched` were
812         /// confirmed. This does not need to equal the current blockchain tip height, which should be
813         /// provided via `cur_height`, however it must never be higher than `cur_height`.
814         pub(crate) fn update_claims_view_from_matched_txn<B: Deref, F: Deref, L: Deref>(
815                 &mut self, txn_matched: &[&Transaction], conf_height: u32, conf_hash: BlockHash,
816                 cur_height: u32, broadcaster: &B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L
817         ) where
818                 B::Target: BroadcasterInterface,
819                 F::Target: FeeEstimator,
820                 L::Target: Logger,
821         {
822                 log_debug!(logger, "Updating claims view at height {} with {} matched transactions in block {}", cur_height, txn_matched.len(), conf_height);
823                 let mut bump_candidates = HashMap::new();
824                 for tx in txn_matched {
825                         // Scan all input to verify is one of the outpoint spent is of interest for us
826                         let mut claimed_outputs_material = Vec::new();
827                         for inp in &tx.input {
828                                 if let Some((claim_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
829                                         // If outpoint has claim request pending on it...
830                                         if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
831                                                 //... we need to verify equality between transaction outpoints and claim request
832                                                 // outpoints to know if transaction is the original claim or a bumped one issued
833                                                 // by us.
834                                                 let mut are_sets_equal = true;
835                                                 let mut tx_inputs = tx.input.iter().map(|input| &input.previous_output).collect::<Vec<_>>();
836                                                 tx_inputs.sort_unstable();
837                                                 for request_input in request.outpoints() {
838                                                         if tx_inputs.binary_search(&request_input).is_err() {
839                                                                 are_sets_equal = false;
840                                                                 break;
841                                                         }
842                                                 }
843
844                                                 macro_rules! clean_claim_request_after_safety_delay {
845                                                         () => {
846                                                                 let entry = OnchainEventEntry {
847                                                                         txid: tx.txid(),
848                                                                         height: conf_height,
849                                                                         block_hash: Some(conf_hash),
850                                                                         event: OnchainEvent::Claim { claim_id: *claim_id }
851                                                                 };
852                                                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
853                                                                         self.onchain_events_awaiting_threshold_conf.push(entry);
854                                                                 }
855                                                         }
856                                                 }
857
858                                                 // If this is our transaction (or our counterparty spent all the outputs
859                                                 // before we could anyway with same inputs order than us), wait for
860                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
861                                                 if are_sets_equal {
862                                                         clean_claim_request_after_safety_delay!();
863                                                 } else { // If false, generate new claim request with update outpoint set
864                                                         let mut at_least_one_drop = false;
865                                                         for input in tx.input.iter() {
866                                                                 if let Some(package) = request.split_package(&input.previous_output) {
867                                                                         claimed_outputs_material.push(package);
868                                                                         at_least_one_drop = true;
869                                                                 }
870                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
871                                                                 if request.outpoints().is_empty() {
872                                                                         clean_claim_request_after_safety_delay!();
873                                                                 }
874                                                         }
875                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
876                                                         if at_least_one_drop {
877                                                                 bump_candidates.insert(*claim_id, request.clone());
878                                                                 // If we have any pending claim events for the request being updated
879                                                                 // that have yet to be consumed, we'll remove them since they will
880                                                                 // end up producing an invalid transaction by double spending
881                                                                 // input(s) that already have a confirmed spend. If such spend is
882                                                                 // reorged out of the chain, then we'll attempt to re-spend the
883                                                                 // inputs once we see it.
884                                                                 #[cfg(debug_assertions)] {
885                                                                         let existing = self.pending_claim_events.iter()
886                                                                                 .filter(|entry| entry.0 == *claim_id).count();
887                                                                         assert!(existing == 0 || existing == 1);
888                                                                 }
889                                                                 self.pending_claim_events.retain(|entry| entry.0 != *claim_id);
890                                                         }
891                                                 }
892                                                 break; //No need to iterate further, either tx is our or their
893                                         } else {
894                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
895                                         }
896                                 }
897                         }
898                         for package in claimed_outputs_material.drain(..) {
899                                 let entry = OnchainEventEntry {
900                                         txid: tx.txid(),
901                                         height: conf_height,
902                                         block_hash: Some(conf_hash),
903                                         event: OnchainEvent::ContentiousOutpoint { package },
904                                 };
905                                 if !self.onchain_events_awaiting_threshold_conf.contains(&entry) {
906                                         self.onchain_events_awaiting_threshold_conf.push(entry);
907                                 }
908                         }
909                 }
910
911                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
912                 let onchain_events_awaiting_threshold_conf =
913                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
914                 for entry in onchain_events_awaiting_threshold_conf {
915                         if entry.has_reached_confirmation_threshold(cur_height) {
916                                 match entry.event {
917                                         OnchainEvent::Claim { claim_id } => {
918                                                 // We may remove a whole set of claim outpoints here, as these one may have
919                                                 // been aggregated in a single tx and claimed so atomically
920                                                 if let Some(request) = self.pending_claim_requests.remove(&claim_id) {
921                                                         for outpoint in request.outpoints() {
922                                                                 log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
923                                                                         outpoint, log_bytes!(claim_id.0));
924                                                                 self.claimable_outpoints.remove(outpoint);
925                                                         }
926                                                         #[cfg(debug_assertions)] {
927                                                                 let num_existing = self.pending_claim_events.iter()
928                                                                         .filter(|entry| entry.0 == claim_id).count();
929                                                                 assert!(num_existing == 0 || num_existing == 1);
930                                                         }
931                                                         self.pending_claim_events.retain(|(id, _)| *id != claim_id);
932                                                 }
933                                         },
934                                         OnchainEvent::ContentiousOutpoint { package } => {
935                                                 log_debug!(logger, "Removing claim tracking due to maturation of claim tx for outpoints:");
936                                                 log_debug!(logger, " {:?}", package.outpoints());
937                                                 self.claimable_outpoints.remove(package.outpoints()[0]);
938                                         }
939                                 }
940                         } else {
941                                 self.onchain_events_awaiting_threshold_conf.push(entry);
942                         }
943                 }
944
945                 // Check if any pending claim request must be rescheduled
946                 for (claim_id, request) in self.pending_claim_requests.iter() {
947                         if cur_height >= request.timer() {
948                                 bump_candidates.insert(*claim_id, request.clone());
949                         }
950                 }
951
952                 // Build, bump and rebroadcast tx accordingly
953                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
954                 for (claim_id, request) in bump_candidates.iter() {
955                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
956                                 cur_height, &request, true /* force_feerate_bump */, &*fee_estimator, &*logger,
957                         ) {
958                                 match bump_claim {
959                                         OnchainClaim::Tx(bump_tx) => {
960                                                 log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx));
961                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
962                                         },
963                                         OnchainClaim::Event(claim_event) => {
964                                                 log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
965                                                 #[cfg(debug_assertions)] {
966                                                         let num_existing = self.pending_claim_events.iter().
967                                                                 filter(|entry| entry.0 == *claim_id).count();
968                                                         assert!(num_existing == 0 || num_existing == 1);
969                                                 }
970                                                 self.pending_claim_events.retain(|event| event.0 != *claim_id);
971                                                 self.pending_claim_events.push((*claim_id, claim_event));
972                                         },
973                                 }
974                                 if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
975                                         request.set_timer(new_timer);
976                                         request.set_feerate(new_feerate);
977                                 }
978                         }
979                 }
980         }
981
982         pub(crate) fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
983                 &mut self,
984                 txid: &Txid,
985                 broadcaster: B,
986                 fee_estimator: &LowerBoundedFeeEstimator<F>,
987                 logger: L,
988         ) where
989                 B::Target: BroadcasterInterface,
990                 F::Target: FeeEstimator,
991                 L::Target: Logger,
992         {
993                 let mut height = None;
994                 for entry in self.onchain_events_awaiting_threshold_conf.iter() {
995                         if entry.txid == *txid {
996                                 height = Some(entry.height);
997                                 break;
998                         }
999                 }
1000
1001                 if let Some(height) = height {
1002                         self.block_disconnected(height, broadcaster, fee_estimator, logger);
1003                 }
1004         }
1005
1006         pub(crate) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: L)
1007                 where B::Target: BroadcasterInterface,
1008                       F::Target: FeeEstimator,
1009                                         L::Target: Logger,
1010         {
1011                 let mut bump_candidates = HashMap::new();
1012                 let onchain_events_awaiting_threshold_conf =
1013                         self.onchain_events_awaiting_threshold_conf.drain(..).collect::<Vec<_>>();
1014                 for entry in onchain_events_awaiting_threshold_conf {
1015                         if entry.height >= height {
1016                                 //- our claim tx on a commitment tx output
1017                                 //- resurect outpoint back in its claimable set and regenerate tx
1018                                 match entry.event {
1019                                         OnchainEvent::ContentiousOutpoint { package } => {
1020                                                 if let Some(pending_claim) = self.claimable_outpoints.get(package.outpoints()[0]) {
1021                                                         if let Some(request) = self.pending_claim_requests.get_mut(&pending_claim.0) {
1022                                                                 request.merge_package(package);
1023                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
1024                                                                 // resurrected only one bump claim tx is going to be broadcast
1025                                                                 bump_candidates.insert(pending_claim.clone(), request.clone());
1026                                                         }
1027                                                 }
1028                                         },
1029                                         _ => {},
1030                                 }
1031                         } else {
1032                                 self.onchain_events_awaiting_threshold_conf.push(entry);
1033                         }
1034                 }
1035                 for ((_claim_id, _), ref mut request) in bump_candidates.iter_mut() {
1036                         // `height` is the height being disconnected, so our `current_height` is 1 lower.
1037                         let current_height = height - 1;
1038                         if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(
1039                                 current_height, &request, true /* force_feerate_bump */, fee_estimator, &&*logger
1040                         ) {
1041                                 request.set_timer(new_timer);
1042                                 request.set_feerate(new_feerate);
1043                                 match bump_claim {
1044                                         OnchainClaim::Tx(bump_tx) => {
1045                                                 log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx));
1046                                                 broadcaster.broadcast_transactions(&[&bump_tx]);
1047                                         },
1048                                         OnchainClaim::Event(claim_event) => {
1049                                                 log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
1050                                                 #[cfg(debug_assertions)] {
1051                                                         let num_existing = self.pending_claim_events.iter()
1052                                                                 .filter(|entry| entry.0 == *_claim_id).count();
1053                                                         assert!(num_existing == 0 || num_existing == 1);
1054                                                 }
1055                                                 self.pending_claim_events.retain(|event| event.0 != *_claim_id);
1056                                                 self.pending_claim_events.push((*_claim_id, claim_event));
1057                                         },
1058                                 }
1059                         }
1060                 }
1061                 for (ancestor_claim_txid, request) in bump_candidates.drain() {
1062                         self.pending_claim_requests.insert(ancestor_claim_txid.0, request);
1063                 }
1064                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
1065                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
1066                 let mut remove_request = Vec::new();
1067                 self.claimable_outpoints.retain(|_, ref v|
1068                         if v.1 >= height {
1069                         remove_request.push(v.0.clone());
1070                         false
1071                         } else { true });
1072                 for req in remove_request {
1073                         self.pending_claim_requests.remove(&req);
1074                 }
1075         }
1076
1077         pub(crate) fn is_output_spend_pending(&self, outpoint: &BitcoinOutPoint) -> bool {
1078                 self.claimable_outpoints.get(outpoint).is_some()
1079         }
1080
1081         pub(crate) fn get_relevant_txids(&self) -> Vec<(Txid, Option<BlockHash>)> {
1082                 let mut txids: Vec<(Txid, Option<BlockHash>)> = self.onchain_events_awaiting_threshold_conf
1083                         .iter()
1084                         .map(|entry| (entry.txid, entry.block_hash))
1085                         .collect();
1086                 txids.sort_unstable_by_key(|(txid, _)| *txid);
1087                 txids.dedup();
1088                 txids
1089         }
1090
1091         pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
1092                 self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
1093         }
1094
1095         pub(crate) fn get_unsigned_holder_commitment_tx(&self) -> &Transaction {
1096                 &self.holder_commitment.trust().built_transaction().transaction
1097         }
1098
1099         //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may
1100         // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created,
1101         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
1102         // to monitor before.
1103         pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1104                 let sig = self.signer.sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
1105                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1106         }
1107
1108         #[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
1109         pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
1110                 let sig = self.signer.unsafe_sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
1111                 self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
1112         }
1113
1114         pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1115                 let get_signed_htlc_tx = |holder_commitment: &HolderCommitmentTransaction| {
1116                         let trusted_tx = holder_commitment.trust();
1117                         if trusted_tx.txid() != outp.txid {
1118                                 return None;
1119                         }
1120                         let (htlc_idx, htlc) = trusted_tx.htlcs().iter().enumerate()
1121                                 .find(|(_, htlc)| htlc.transaction_output_index.unwrap() == outp.vout)
1122                                 .unwrap();
1123                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1124                         let mut htlc_tx = trusted_tx.build_unsigned_htlc_tx(
1125                                 &self.channel_transaction_parameters.as_holder_broadcastable(), htlc_idx, preimage,
1126                         );
1127
1128                         let htlc_descriptor = HTLCDescriptor {
1129                                 channel_derivation_parameters: ChannelDerivationParameters {
1130                                         value_satoshis: self.channel_value_satoshis,
1131                                         keys_id: self.channel_keys_id,
1132                                         transaction_parameters: self.channel_transaction_parameters.clone(),
1133                                 },
1134                                 commitment_txid: trusted_tx.txid(),
1135                                 per_commitment_number: trusted_tx.commitment_number(),
1136                                 per_commitment_point: trusted_tx.per_commitment_point(),
1137                                 feerate_per_kw: trusted_tx.feerate_per_kw(),
1138                                 htlc: htlc.clone(),
1139                                 preimage: preimage.clone(),
1140                                 counterparty_sig: counterparty_htlc_sig.clone(),
1141                         };
1142                         let htlc_sig = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx).unwrap();
1143                         htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness(
1144                                 htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage,
1145                         );
1146                         Some(htlc_tx)
1147                 };
1148
1149                 // Check if the HTLC spends from the current holder commitment first, or the previous.
1150                 get_signed_htlc_tx(&self.holder_commitment)
1151                         .or_else(|| self.prev_holder_commitment.as_ref().and_then(|prev_holder_commitment| get_signed_htlc_tx(prev_holder_commitment)))
1152         }
1153
1154         pub(crate) fn generate_external_htlc_claim(
1155                 &self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>
1156         ) -> Option<ExternalHTLCClaim> {
1157                 let find_htlc = |holder_commitment: &HolderCommitmentTransaction| -> Option<ExternalHTLCClaim> {
1158                         let trusted_tx = holder_commitment.trust();
1159                         if outp.txid != trusted_tx.txid() {
1160                                 return None;
1161                         }
1162                         trusted_tx.htlcs().iter().enumerate()
1163                                 .find(|(_, htlc)| if let Some(output_index) = htlc.transaction_output_index {
1164                                         output_index == outp.vout
1165                                 } else {
1166                                         false
1167                                 })
1168                                 .map(|(htlc_idx, htlc)| {
1169                                         let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[htlc_idx];
1170                                         ExternalHTLCClaim {
1171                                                 commitment_txid: trusted_tx.txid(),
1172                                                 per_commitment_number: trusted_tx.commitment_number(),
1173                                                 htlc: htlc.clone(),
1174                                                 preimage: *preimage,
1175                                                 counterparty_sig: counterparty_htlc_sig,
1176                                         }
1177                                 })
1178                 };
1179                 // Check if the HTLC spends from the current holder commitment or the previous one otherwise.
1180                 find_htlc(&self.holder_commitment)
1181                         .or_else(|| self.prev_holder_commitment.as_ref().map(|c| find_htlc(c)).flatten())
1182         }
1183
1184         pub(crate) fn channel_type_features(&self) -> &ChannelTypeFeatures {
1185                 &self.channel_transaction_parameters.channel_type_features
1186         }
1187 }