1 //! The logic to build claims and bump in-flight transactions until confirmations.
3 //! OnchainTxHandler objetcs are fully-part of ChannelMonitor and encapsulates all
4 //! building, tracking, bumping and notifications functions.
6 use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
7 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
8 use bitcoin::blockdata::script::Script;
9 use bitcoin::util::bip143;
11 use bitcoin_hashes::sha256d::Hash as Sha256dHash;
13 use secp256k1::Secp256k1;
16 use ln::msgs::DecodeError;
17 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
18 use ln::chan_utils::{HTLCType, LocalCommitmentTransaction};
19 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
20 use chain::keysinterface::ChannelKeys;
21 use util::logger::Logger;
22 use util::ser::{ReadableArgs, Readable, Writer, Writeable};
25 use std::collections::{HashMap, hash_map, HashSet};
30 const MAX_ALLOC_SIZE: usize = 64*1024;
32 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
33 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
34 #[derive(Clone, PartialEq)]
36 /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
37 /// bump-txn candidate buffer.
39 claim_request: Sha256dHash,
41 /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
42 /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
43 /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
45 outpoint: BitcoinOutPoint,
46 input_material: InputMaterial,
50 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
51 #[derive(Clone, PartialEq)]
52 pub struct ClaimTxBumpMaterial {
53 // At every block tick, used to check if pending claiming tx is taking too
54 // much time for confirmation and we need to bump it.
55 height_timer: Option<u32>,
56 // Tracked in case of reorg to wipe out now-superflous bump material
57 feerate_previous: u64,
58 // Soonest timelocks among set of outpoints claimed, used to compute
59 // a priority of not feerate
60 soonest_timelock: u32,
61 // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
62 per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
65 impl Writeable for ClaimTxBumpMaterial {
66 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
67 self.height_timer.write(writer)?;
68 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
69 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
70 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
71 for (outp, tx_material) in self.per_input_material.iter() {
73 tx_material.write(writer)?;
79 impl Readable for ClaimTxBumpMaterial {
80 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
81 let height_timer = Readable::read(reader)?;
82 let feerate_previous = Readable::read(reader)?;
83 let soonest_timelock = Readable::read(reader)?;
84 let per_input_material_len: u64 = Readable::read(reader)?;
85 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
86 for _ in 0 ..per_input_material_len {
87 let outpoint = Readable::read(reader)?;
88 let input_material = Readable::read(reader)?;
89 per_input_material.insert(outpoint, input_material);
91 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
96 pub(super) enum InputDescriptors {
101 RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
104 macro_rules! subtract_high_prio_fee {
105 ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
107 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
108 let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
110 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
111 fee = $used_feerate * ($predicted_weight as u64) / 1000;
113 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
114 fee = $used_feerate * ($predicted_weight as u64) / 1000;
116 log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
120 log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
126 log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
140 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
141 /// do RBF bumping if possible.
142 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
143 destination_script: Script,
144 funding_redeemscript: Script,
145 local_commitment: Option<LocalCommitmentTransaction>,
146 prev_local_commitment: Option<LocalCommitmentTransaction>,
148 key_storage: ChanSigner,
150 // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
151 // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
152 // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
153 // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
154 // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
155 // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
156 // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
157 // we need to regenerate new claim request with reduced set of still-claimable outpoints.
158 // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
159 // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
160 // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
161 #[cfg(test)] // Used in functional_test to verify sanitization
162 pub pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
164 pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
166 // Used to link outpoints claimed in a connected block to a pending claim request.
167 // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
168 // Value is (pending claim request identifier, confirmation_block), identifier
169 // is txid of the initial claiming transaction and is immutable until outpoint is
170 // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
171 // block with output gets disconnected.
172 #[cfg(test)] // Used in functional_test to verify sanitization
173 pub claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
175 claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
177 onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
179 secp_ctx: Secp256k1<secp256k1::All>,
183 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
184 pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
185 self.destination_script.write(writer)?;
186 self.funding_redeemscript.write(writer)?;
187 self.local_commitment.write(writer)?;
188 self.prev_local_commitment.write(writer)?;
190 self.key_storage.write(writer)?;
192 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
193 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
194 ancestor_claim_txid.write(writer)?;
195 claim_tx_data.write(writer)?;
198 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
199 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
201 claim_and_height.0.write(writer)?;
202 claim_and_height.1.write(writer)?;
205 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
206 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
207 writer.write_all(&byte_utils::be32_to_array(**target))?;
208 writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
209 for ev in events.iter() {
211 OnchainEvent::Claim { ref claim_request } => {
212 writer.write_all(&[0; 1])?;
213 claim_request.write(writer)?;
215 OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
216 writer.write_all(&[1; 1])?;
217 outpoint.write(writer)?;
218 input_material.write(writer)?;
227 impl<ChanSigner: ChannelKeys + Readable> ReadableArgs<Arc<Logger>> for OnchainTxHandler<ChanSigner> {
228 fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
229 let destination_script = Readable::read(reader)?;
230 let funding_redeemscript = Readable::read(reader)?;
231 let local_commitment = Readable::read(reader)?;
232 let prev_local_commitment = Readable::read(reader)?;
234 let key_storage = Readable::read(reader)?;
236 let pending_claim_requests_len: u64 = Readable::read(reader)?;
237 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
238 for _ in 0..pending_claim_requests_len {
239 pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
242 let claimable_outpoints_len: u64 = Readable::read(reader)?;
243 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
244 for _ in 0..claimable_outpoints_len {
245 let outpoint = Readable::read(reader)?;
246 let ancestor_claim_txid = Readable::read(reader)?;
247 let height = Readable::read(reader)?;
248 claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
250 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
251 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
252 for _ in 0..waiting_threshold_conf_len {
253 let height_target = Readable::read(reader)?;
254 let events_len: u64 = Readable::read(reader)?;
255 let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
256 for _ in 0..events_len {
257 let ev = match <u8 as Readable>::read(reader)? {
259 let claim_request = Readable::read(reader)?;
260 OnchainEvent::Claim {
265 let outpoint = Readable::read(reader)?;
266 let input_material = Readable::read(reader)?;
267 OnchainEvent::ContentiousOutpoint {
272 _ => return Err(DecodeError::InvalidValue),
276 onchain_events_waiting_threshold_conf.insert(height_target, events);
279 Ok(OnchainTxHandler {
281 funding_redeemscript,
283 prev_local_commitment,
286 pending_claim_requests,
287 onchain_events_waiting_threshold_conf,
288 secp_ctx: Secp256k1::new(),
294 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
295 pub(super) fn new(destination_script: Script, keys: ChanSigner, funding_redeemscript: Script, logger: Arc<Logger>) -> Self {
297 let key_storage = keys;
301 funding_redeemscript,
302 local_commitment: None,
303 prev_local_commitment: None,
305 pending_claim_requests: HashMap::new(),
306 claimable_outpoints: HashMap::new(),
307 onchain_events_waiting_threshold_conf: HashMap::new(),
309 secp_ctx: Secp256k1::new(),
314 pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
315 let mut tx_weight = 2; // count segwit flags
317 // We use expected weight (and not actual) as signatures and time lock delays may vary
318 tx_weight += match inp {
319 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
320 &InputDescriptors::RevokedOfferedHTLC => {
321 1 + 1 + 73 + 1 + 33 + 1 + 133
323 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
324 &InputDescriptors::RevokedReceivedHTLC => {
325 1 + 1 + 73 + 1 + 33 + 1 + 139
327 // number_of_witness_elements + sig_length + remotehtlc_sig + preimage_length + preimage + witness_script_length + witness_script
328 &InputDescriptors::OfferedHTLC => {
329 1 + 1 + 73 + 1 + 32 + 1 + 133
331 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
332 &InputDescriptors::ReceivedHTLC => {
333 1 + 1 + 73 + 1 + 1 + 1 + 139
335 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
336 &InputDescriptors::RevokedOutput => {
337 1 + 1 + 73 + 1 + 1 + 1 + 77
344 /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
345 /// output detection, we generate a first version of a claim tx and associate to it a height timer. A height timer is an absolute block
346 /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
347 /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
348 /// frequency of the bump and so increase our bets of success.
349 fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
350 if timelock_expiration <= current_height + 3 {
351 return current_height + 1
352 } else if timelock_expiration - current_height <= 15 {
353 return current_height + 3
358 /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize coutnerparty onchain) lays on the assumption of claim transactions getting confirmed before timelock expiration
359 /// (CSV or CLTV following cases). In case of high-fee spikes, claim tx may stuck in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or Child-Pay-For-Parent.
360 fn generate_claim_tx<F: Deref>(&self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(Option<u32>, u64, Transaction)>
361 where F::Target: FeeEstimator
363 if cached_claim_datas.per_input_material.len() == 0 { return None } // But don't prune pending claiming request yet, we may have to resurrect HTLCs
364 let mut inputs = Vec::new();
365 for outp in cached_claim_datas.per_input_material.keys() {
366 log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
368 previous_output: *outp,
369 script_sig: Script::new(),
370 sequence: 0xfffffffd,
374 let mut bumped_tx = Transaction {
379 script_pubkey: self.destination_script.clone(),
384 macro_rules! RBF_bump {
385 ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
387 let mut used_feerate;
388 // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
389 let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
390 let mut value = $amount;
391 if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
392 // Overflow check is done in subtract_high_prio_fee
395 log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
398 // ...else just increase the previous feerate by 25% (because that's a nice number)
400 let fee = $old_feerate * $predicted_weight / 750;
402 log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
408 let previous_fee = $old_feerate * $predicted_weight / 1000;
409 let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
410 // BIP 125 Opt-in Full Replace-by-Fee Signaling
411 // * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
412 // * 4. The replacement transaction must also pay for its own bandwidth at or above the rate set by the node's minimum relay fee setting.
413 let new_fee = if new_fee < previous_fee + min_relay_fee {
414 new_fee + previous_fee + min_relay_fee - new_fee
418 Some((new_fee, new_fee * 1000 / $predicted_weight))
423 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
424 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
425 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
426 let mut inputs_witnesses_weight = 0;
428 let mut dynamic_fee = true;
429 for per_outp_material in cached_claim_datas.per_input_material.values() {
430 match per_outp_material {
431 &InputMaterial::Revoked { ref witness_script, ref is_htlc, ref amount, .. } => {
432 inputs_witnesses_weight += Self::get_witnesses_weight(if !is_htlc { &[InputDescriptors::RevokedOutput] } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::OfferedHTLC) { &[InputDescriptors::RevokedOfferedHTLC] } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::AcceptedHTLC) { &[InputDescriptors::RevokedReceivedHTLC] } else { unreachable!() });
435 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
436 inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
439 &InputMaterial::LocalHTLC { .. } => { return None; }
440 &InputMaterial::Funding { .. } => {
447 let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
449 // If old feerate is 0, first iteration of this claim, use normal fee calculation
450 if cached_claim_datas.feerate_previous != 0 {
451 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
452 // If new computed fee is superior at the whole claimable amount burn all in fees
454 bumped_tx.output[0].value = 0;
456 bumped_tx.output[0].value = amt - new_fee;
458 new_feerate = feerate;
459 } else { return None; }
461 if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
462 bumped_tx.output[0].value = amt;
463 } else { return None; }
465 assert!(new_feerate != 0);
467 for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
468 match per_outp_material {
469 &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref is_htlc, ref amount } => {
470 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
471 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
472 let sig = self.secp_ctx.sign(&sighash, &key);
473 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
474 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
476 bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
478 bumped_tx.input[i].witness.push(vec!(1));
480 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
481 log_trace!(self, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if !is_htlc { "to_local" } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::OfferedHTLC) { "offered" } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::AcceptedHTLC) { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
483 &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
484 if !preimage.is_some() { bumped_tx.lock_time = *locktime }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation
485 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
486 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
487 let sig = self.secp_ctx.sign(&sighash, &key);
488 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
489 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
490 if let &Some(preimage) = preimage {
491 bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
493 bumped_tx.input[i].witness.push(vec![]);
495 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
496 log_trace!(self, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);
501 log_trace!(self, "...with timer {}", new_timer.unwrap());
502 assert!(predicted_weight >= bumped_tx.get_weight());
503 return Some((new_timer, new_feerate, bumped_tx))
505 for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
506 match per_outp_material {
507 &InputMaterial::LocalHTLC { .. } => {
508 //TODO : Given that Local Commitment Transaction and HTLC-Timeout/HTLC-Success are counter-signed by peer, we can't
509 // RBF them. Need a Lightning specs change and package relay modification :
510 // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
513 &InputMaterial::Funding { ref channel_value } => {
514 if self.local_commitment.is_some() {
515 let mut local_commitment = self.local_commitment.clone().unwrap();
516 self.key_storage.sign_local_commitment(&mut local_commitment, &self.funding_redeemscript, *channel_value, &self.secp_ctx);
517 let signed_tx = local_commitment.with_valid_witness().clone();
518 let mut amt_outputs = 0;
519 for outp in signed_tx.output.iter() {
520 amt_outputs += outp.value;
522 let feerate = (channel_value - amt_outputs) * 1000 / signed_tx.get_weight() as u64;
523 // Timer set to $NEVER given we can't bump tx without anchor outputs
524 log_trace!(self, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
525 return Some((None, feerate, signed_tx));
535 pub(super) fn block_connected<B: Deref, F: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<ClaimRequest>, height: u32, broadcaster: B, fee_estimator: F)
536 where B::Target: BroadcasterInterface,
537 F::Target: FeeEstimator
539 log_trace!(self, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
540 let mut new_claims = Vec::new();
541 let mut aggregated_claim = HashMap::new();
542 let mut aggregated_soonest = ::std::u32::MAX;
544 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
545 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
546 for req in claimable_outpoints {
547 // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
548 if let Some(_) = self.claimable_outpoints.get(&req.outpoint) { log_trace!(self, "Bouncing off outpoint {}:{}, already registered its claiming request", req.outpoint.txid, req.outpoint.vout); } else {
549 log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
550 if req.absolute_timelock <= height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable { // Don't aggregate if outpoint absolute timelock is soon or marked as non-aggregable
551 let mut single_input = HashMap::new();
552 single_input.insert(req.outpoint, req.witness_data);
553 new_claims.push((req.absolute_timelock, single_input));
555 aggregated_claim.insert(req.outpoint, req.witness_data);
556 if req.absolute_timelock < aggregated_soonest {
557 aggregated_soonest = req.absolute_timelock;
562 new_claims.push((aggregated_soonest, aggregated_claim));
564 // Generate claim transactions and track them to bump if necessary at
565 // height timer expiration (i.e in how many blocks we're going to take action).
566 for claim in new_claims {
567 let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock: claim.0, per_input_material: claim.1.clone() };
568 if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
569 claim_material.height_timer = new_timer;
570 claim_material.feerate_previous = new_feerate;
571 let txid = tx.txid();
572 self.pending_claim_requests.insert(txid, claim_material);
573 for k in claim.1.keys() {
574 log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
575 self.claimable_outpoints.insert(k.clone(), (txid, height));
577 log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
578 broadcaster.broadcast_transaction(&tx);
582 let mut bump_candidates = HashSet::new();
583 for tx in txn_matched {
584 // Scan all input to verify is one of the outpoint spent is of interest for us
585 let mut claimed_outputs_material = Vec::new();
586 for inp in &tx.input {
587 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
588 // If outpoint has claim request pending on it...
589 if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
590 //... we need to verify equality between transaction outpoints and claim request
591 // outpoints to know if transaction is the original claim or a bumped one issued
593 let mut set_equality = true;
594 if claim_material.per_input_material.len() != tx.input.len() {
595 set_equality = false;
597 for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
598 if *claim_inp != tx_inp.previous_output {
599 set_equality = false;
604 macro_rules! clean_claim_request_after_safety_delay {
606 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
607 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
608 hash_map::Entry::Occupied(mut entry) => {
609 if !entry.get().contains(&new_event) {
610 entry.get_mut().push(new_event);
613 hash_map::Entry::Vacant(entry) => {
614 entry.insert(vec![new_event]);
620 // If this is our transaction (or our counterparty spent all the outputs
621 // before we could anyway with same inputs order than us), wait for
622 // ANTI_REORG_DELAY and clean the RBF tracking map.
624 clean_claim_request_after_safety_delay!();
625 } else { // If false, generate new claim request with update outpoint set
626 let mut at_least_one_drop = false;
627 for input in tx.input.iter() {
628 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
629 claimed_outputs_material.push((input.previous_output, input_material));
630 at_least_one_drop = true;
632 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
633 if claim_material.per_input_material.is_empty() {
634 clean_claim_request_after_safety_delay!();
637 //TODO: recompute soonest_timelock to avoid wasting a bit on fees
638 if at_least_one_drop {
639 bump_candidates.insert(first_claim_txid_height.0.clone());
642 break; //No need to iterate further, either tx is our or their
644 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
648 for (outpoint, input_material) in claimed_outputs_material.drain(..) {
649 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
650 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
651 hash_map::Entry::Occupied(mut entry) => {
652 if !entry.get().contains(&new_event) {
653 entry.get_mut().push(new_event);
656 hash_map::Entry::Vacant(entry) => {
657 entry.insert(vec![new_event]);
663 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
664 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
667 OnchainEvent::Claim { claim_request } => {
668 // We may remove a whole set of claim outpoints here, as these one may have
669 // been aggregated in a single tx and claimed so atomically
670 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
671 for outpoint in bump_material.per_input_material.keys() {
672 self.claimable_outpoints.remove(&outpoint);
676 OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
677 self.claimable_outpoints.remove(&outpoint);
683 // Check if any pending claim request must be rescheduled
684 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
685 if let Some(h) = claim_data.height_timer {
687 bump_candidates.insert(*first_claim_txid);
692 // Build, bump and rebroadcast tx accordingly
693 log_trace!(self, "Bumping {} candidates", bump_candidates.len());
694 for first_claim_txid in bump_candidates.iter() {
695 if let Some((new_timer, new_feerate)) = {
696 if let Some(claim_material) = self.pending_claim_requests.get(first_claim_txid) {
697 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
698 log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
699 broadcaster.broadcast_transaction(&bump_tx);
700 Some((new_timer, new_feerate))
702 } else { unreachable!(); }
704 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
705 claim_material.height_timer = new_timer;
706 claim_material.feerate_previous = new_feerate;
707 } else { unreachable!(); }
712 pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
713 where B::Target: BroadcasterInterface,
714 F::Target: FeeEstimator
716 let mut bump_candidates = HashMap::new();
717 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
718 //- our claim tx on a commitment tx output
719 //- resurect outpoint back in its claimable set and regenerate tx
722 OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
723 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
724 if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
725 claim_material.per_input_material.insert(outpoint, input_material);
726 // Using a HashMap guarantee us than if we have multiple outpoints getting
727 // resurrected only one bump claim tx is going to be broadcast
728 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
736 for (_, claim_material) in bump_candidates.iter_mut() {
737 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
738 claim_material.height_timer = new_timer;
739 claim_material.feerate_previous = new_feerate;
740 broadcaster.broadcast_transaction(&bump_tx);
743 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
744 self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
746 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
747 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
748 let mut remove_request = Vec::new();
749 self.claimable_outpoints.retain(|_, ref v|
751 remove_request.push(v.0.clone());
754 for req in remove_request {
755 self.pending_claim_requests.remove(&req);
759 pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
760 // To prevent any unsafe state discrepancy between offchain and onchain, once local
761 // commitment transaction has been signed due to an event (either block height for
762 // HTLC-timeout or channel force-closure), don't allow any further update of local
763 // commitment transaction view to avoid delivery of revocation secret to counterparty
764 // for the aformentionned signed transaction.
765 if let Some(ref local_commitment) = self.local_commitment {
766 if local_commitment.has_local_sig() { return Err(()) }
768 self.prev_local_commitment = self.local_commitment.take();
769 self.local_commitment = Some(tx);