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::hash_types::Txid;
13 use bitcoin::secp256k1::{Secp256k1, Signature};
14 use bitcoin::secp256k1;
15 use bitcoin::secp256k1::key::PublicKey;
17 use ln::msgs::DecodeError;
18 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
19 use ln::channelmanager::PaymentPreimage;
21 use ln::chan_utils::{TxCreationKeys, LocalCommitmentTransaction, HTLCOutputInCommitment};
22 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
23 use chain::keysinterface::ChannelKeys;
24 use util::logger::Logger;
25 use util::ser::{ReadableArgs, Readable, Writer, Writeable};
28 use std::collections::{HashMap, hash_map};
33 const MAX_ALLOC_SIZE: usize = 64*1024;
35 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
36 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
37 #[derive(Clone, PartialEq)]
39 /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
40 /// bump-txn candidate buffer.
44 /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
45 /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
46 /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
48 outpoint: BitcoinOutPoint,
49 input_material: InputMaterial,
53 /// Cache remote basepoint to compute any transaction on
54 /// remote outputs, either justice or preimage/timeout transactions.
55 struct RemoteTxCache {
56 remote_delayed_payment_base_key: PublicKey,
57 remote_htlc_base_key: PublicKey,
58 per_htlc: HashMap<Txid, Vec<(HTLCOutputInCommitment)>>
61 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
62 #[derive(Clone, PartialEq)]
63 pub struct ClaimTxBumpMaterial {
64 // At every block tick, used to check if pending claiming tx is taking too
65 // much time for confirmation and we need to bump it.
66 height_timer: Option<u32>,
67 // Tracked in case of reorg to wipe out now-superflous bump material
68 feerate_previous: u64,
69 // Soonest timelocks among set of outpoints claimed, used to compute
70 // a priority of not feerate
71 soonest_timelock: u32,
72 // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
73 per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
76 impl Writeable for ClaimTxBumpMaterial {
77 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
78 self.height_timer.write(writer)?;
79 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
80 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
81 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
82 for (outp, tx_material) in self.per_input_material.iter() {
84 tx_material.write(writer)?;
90 impl Readable for ClaimTxBumpMaterial {
91 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
92 let height_timer = Readable::read(reader)?;
93 let feerate_previous = Readable::read(reader)?;
94 let soonest_timelock = Readable::read(reader)?;
95 let per_input_material_len: u64 = Readable::read(reader)?;
96 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
97 for _ in 0 ..per_input_material_len {
98 let outpoint = Readable::read(reader)?;
99 let input_material = Readable::read(reader)?;
100 per_input_material.insert(outpoint, input_material);
102 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
106 #[derive(PartialEq, Clone, Copy)]
107 pub(crate) enum InputDescriptors {
112 RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
115 impl Writeable for InputDescriptors {
116 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
118 &InputDescriptors::RevokedOfferedHTLC => {
119 writer.write_all(&[0; 1])?;
121 &InputDescriptors::RevokedReceivedHTLC => {
122 writer.write_all(&[1; 1])?;
124 &InputDescriptors::OfferedHTLC => {
125 writer.write_all(&[2; 1])?;
127 &InputDescriptors::ReceivedHTLC => {
128 writer.write_all(&[3; 1])?;
130 &InputDescriptors::RevokedOutput => {
131 writer.write_all(&[4; 1])?;
138 impl Readable for InputDescriptors {
139 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
140 let input_descriptor = match <u8 as Readable>::read(reader)? {
142 InputDescriptors::RevokedOfferedHTLC
145 InputDescriptors::RevokedReceivedHTLC
148 InputDescriptors::OfferedHTLC
151 InputDescriptors::ReceivedHTLC
154 InputDescriptors::RevokedOutput
156 _ => return Err(DecodeError::InvalidValue),
162 macro_rules! subtract_high_prio_fee {
163 ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
165 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
166 let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
168 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
169 fee = $used_feerate * ($predicted_weight as u64) / 1000;
171 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
172 fee = $used_feerate * ($predicted_weight as u64) / 1000;
174 log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
178 log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
184 log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
197 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
198 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
199 match Readable::read(reader)? {
202 let vlen: u64 = Readable::read(reader)?;
203 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<Option<(usize, Signature)>>()));
205 ret.push(match Readable::read(reader)? {
207 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
208 _ => return Err(DecodeError::InvalidValue)
213 _ => Err(DecodeError::InvalidValue),
218 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
219 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
223 (vec.len() as u64).write(writer)?;
224 for opt in vec.iter() {
226 &Some((ref idx, ref sig)) => {
228 (*idx as u64).write(writer)?;
231 &None => 0u8.write(writer)?,
235 &None => 0u8.write(writer)?,
242 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
243 /// do RBF bumping if possible.
244 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
245 destination_script: Script,
246 local_commitment: Option<LocalCommitmentTransaction>,
247 // local_htlc_sigs and prev_local_htlc_sigs are in the order as they appear in the commitment
248 // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
249 // the set of HTLCs in the LocalCommitmentTransaction (including those which do not appear in
250 // the commitment transaction).
251 local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
252 prev_local_commitment: Option<LocalCommitmentTransaction>,
253 prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
255 remote_tx_cache: RemoteTxCache,
258 key_storage: ChanSigner,
260 // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
261 // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
262 // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
263 // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
264 // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
265 // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
266 // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
267 // we need to regenerate new claim request with reduced set of still-claimable outpoints.
268 // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
269 // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
270 // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
271 #[cfg(test)] // Used in functional_test to verify sanitization
272 pub pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
274 pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
276 // Used to link outpoints claimed in a connected block to a pending claim request.
277 // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
278 // Value is (pending claim request identifier, confirmation_block), identifier
279 // is txid of the initial claiming transaction and is immutable until outpoint is
280 // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
281 // block with output gets disconnected.
282 #[cfg(test)] // Used in functional_test to verify sanitization
283 pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
285 claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
287 onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
289 secp_ctx: Secp256k1<secp256k1::All>,
293 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
294 pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
295 self.destination_script.write(writer)?;
296 self.local_commitment.write(writer)?;
297 self.local_htlc_sigs.write(writer)?;
298 self.prev_local_commitment.write(writer)?;
299 self.prev_local_htlc_sigs.write(writer)?;
301 self.local_csv.write(writer)?;
303 self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
304 self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
305 writer.write_all(&byte_utils::be64_to_array(self.remote_tx_cache.per_htlc.len() as u64))?;
306 for (ref txid, ref htlcs) in self.remote_tx_cache.per_htlc.iter() {
307 writer.write_all(&txid[..])?;
308 writer.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
309 for &ref htlc in htlcs.iter() {
313 self.remote_csv.write(writer)?;
315 self.key_storage.write(writer)?;
317 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
318 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
319 ancestor_claim_txid.write(writer)?;
320 claim_tx_data.write(writer)?;
323 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
324 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
326 claim_and_height.0.write(writer)?;
327 claim_and_height.1.write(writer)?;
330 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
331 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
332 writer.write_all(&byte_utils::be32_to_array(**target))?;
333 writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
334 for ev in events.iter() {
336 OnchainEvent::Claim { ref claim_request } => {
337 writer.write_all(&[0; 1])?;
338 claim_request.write(writer)?;
340 OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
341 writer.write_all(&[1; 1])?;
342 outpoint.write(writer)?;
343 input_material.write(writer)?;
352 impl<ChanSigner: ChannelKeys + Readable> ReadableArgs<Arc<Logger>> for OnchainTxHandler<ChanSigner> {
353 fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
354 let destination_script = Readable::read(reader)?;
356 let local_commitment = Readable::read(reader)?;
357 let local_htlc_sigs = Readable::read(reader)?;
358 let prev_local_commitment = Readable::read(reader)?;
359 let prev_local_htlc_sigs = Readable::read(reader)?;
361 let local_csv = Readable::read(reader)?;
363 let remote_tx_cache = {
364 let remote_delayed_payment_base_key = Readable::read(reader)?;
365 let remote_htlc_base_key = Readable::read(reader)?;
366 let per_htlc_len: u64 = Readable::read(reader)?;
367 let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
368 for _ in 0..per_htlc_len {
369 let txid: Txid = Readable::read(reader)?;
370 let htlcs_count: u64 = Readable::read(reader)?;
371 let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
372 for _ in 0..htlcs_count {
373 let htlc = Readable::read(reader)?;
376 if let Some(_) = per_htlc.insert(txid, htlcs) {
377 return Err(DecodeError::InvalidValue);
381 remote_delayed_payment_base_key,
382 remote_htlc_base_key,
386 let remote_csv = Readable::read(reader)?;
388 let key_storage = Readable::read(reader)?;
390 let pending_claim_requests_len: u64 = Readable::read(reader)?;
391 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
392 for _ in 0..pending_claim_requests_len {
393 pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
396 let claimable_outpoints_len: u64 = Readable::read(reader)?;
397 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
398 for _ in 0..claimable_outpoints_len {
399 let outpoint = Readable::read(reader)?;
400 let ancestor_claim_txid = Readable::read(reader)?;
401 let height = Readable::read(reader)?;
402 claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
404 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
405 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
406 for _ in 0..waiting_threshold_conf_len {
407 let height_target = Readable::read(reader)?;
408 let events_len: u64 = Readable::read(reader)?;
409 let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
410 for _ in 0..events_len {
411 let ev = match <u8 as Readable>::read(reader)? {
413 let claim_request = Readable::read(reader)?;
414 OnchainEvent::Claim {
419 let outpoint = Readable::read(reader)?;
420 let input_material = Readable::read(reader)?;
421 OnchainEvent::ContentiousOutpoint {
426 _ => return Err(DecodeError::InvalidValue),
430 onchain_events_waiting_threshold_conf.insert(height_target, events);
433 Ok(OnchainTxHandler {
437 prev_local_commitment,
438 prev_local_htlc_sigs,
444 pending_claim_requests,
445 onchain_events_waiting_threshold_conf,
446 secp_ctx: Secp256k1::new(),
452 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
453 pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16, remote_delayed_payment_base_key: PublicKey, remote_htlc_base_key: PublicKey, remote_csv: u16, logger: Arc<Logger>) -> Self {
455 let key_storage = keys;
457 let remote_tx_cache = RemoteTxCache {
458 remote_delayed_payment_base_key,
459 remote_htlc_base_key,
460 per_htlc: HashMap::new(),
465 local_commitment: None,
466 local_htlc_sigs: None,
467 prev_local_commitment: None,
468 prev_local_htlc_sigs: None,
473 pending_claim_requests: HashMap::new(),
474 claimable_outpoints: HashMap::new(),
475 onchain_events_waiting_threshold_conf: HashMap::new(),
477 secp_ctx: Secp256k1::new(),
482 pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
483 let mut tx_weight = 2; // count segwit flags
485 // We use expected weight (and not actual) as signatures and time lock delays may vary
486 tx_weight += match inp {
487 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
488 &InputDescriptors::RevokedOfferedHTLC => {
489 1 + 1 + 73 + 1 + 33 + 1 + 133
491 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
492 &InputDescriptors::RevokedReceivedHTLC => {
493 1 + 1 + 73 + 1 + 33 + 1 + 139
495 // number_of_witness_elements + sig_length + remotehtlc_sig + preimage_length + preimage + witness_script_length + witness_script
496 &InputDescriptors::OfferedHTLC => {
497 1 + 1 + 73 + 1 + 32 + 1 + 133
499 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
500 &InputDescriptors::ReceivedHTLC => {
501 1 + 1 + 73 + 1 + 1 + 1 + 139
503 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
504 &InputDescriptors::RevokedOutput => {
505 1 + 1 + 73 + 1 + 1 + 1 + 77
512 /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
513 /// 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
514 /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
515 /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
516 /// frequency of the bump and so increase our bets of success.
517 fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
518 if timelock_expiration <= current_height + 3 {
519 return current_height + 1
520 } else if timelock_expiration - current_height <= 15 {
521 return current_height + 3
526 /// 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
527 /// (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.
528 fn generate_claim_tx<F: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(Option<u32>, u64, Transaction)>
529 where F::Target: FeeEstimator
531 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
532 let mut inputs = Vec::new();
533 for outp in cached_claim_datas.per_input_material.keys() {
534 log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
536 previous_output: *outp,
537 script_sig: Script::new(),
538 sequence: 0xfffffffd,
542 let mut bumped_tx = Transaction {
547 script_pubkey: self.destination_script.clone(),
552 macro_rules! RBF_bump {
553 ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
555 let mut used_feerate;
556 // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
557 let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
558 let mut value = $amount;
559 if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
560 // Overflow check is done in subtract_high_prio_fee
563 log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
566 // ...else just increase the previous feerate by 25% (because that's a nice number)
568 let fee = $old_feerate * $predicted_weight / 750;
570 log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
576 let previous_fee = $old_feerate * $predicted_weight / 1000;
577 let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
578 // BIP 125 Opt-in Full Replace-by-Fee Signaling
579 // * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
580 // * 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.
581 let new_fee = if new_fee < previous_fee + min_relay_fee {
582 new_fee + previous_fee + min_relay_fee - new_fee
586 Some((new_fee, new_fee * 1000 / $predicted_weight))
591 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
592 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
593 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
594 let mut inputs_witnesses_weight = 0;
596 let mut dynamic_fee = true;
597 for per_outp_material in cached_claim_datas.per_input_material.values() {
598 match per_outp_material {
599 &InputMaterial::Revoked { ref input_descriptor, ref amount, .. } => {
600 inputs_witnesses_weight += Self::get_witnesses_weight(&[*input_descriptor]);
603 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
604 inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
607 &InputMaterial::LocalHTLC { .. } => {
610 &InputMaterial::Funding { .. } => {
616 let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
618 // If old feerate is 0, first iteration of this claim, use normal fee calculation
619 if cached_claim_datas.feerate_previous != 0 {
620 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
621 // If new computed fee is superior at the whole claimable amount burn all in fees
623 bumped_tx.output[0].value = 0;
625 bumped_tx.output[0].value = amt - new_fee;
627 new_feerate = feerate;
628 } else { return None; }
630 if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
631 bumped_tx.output[0].value = amt;
632 } else { return None; }
634 assert!(new_feerate != 0);
636 for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
637 match per_outp_material {
638 &InputMaterial::Revoked { ref per_commitment_point, ref per_commitment_key, ref input_descriptor, ref amount } => {
639 if let Ok(chan_keys) = TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, &self.remote_tx_cache.remote_delayed_payment_base_key, &self.remote_tx_cache.remote_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
641 let mut this_htlc = None;
642 if *input_descriptor != InputDescriptors::RevokedOutput {
643 if let Some(htlcs) = self.remote_tx_cache.per_htlc.get(&outp.txid) {
645 if htlc.transaction_output_index.unwrap() == outp.vout {
646 this_htlc = Some(htlc);
652 let witness_script = if *input_descriptor != InputDescriptors::RevokedOutput && this_htlc.is_some() {
653 chan_utils::get_htlc_redeemscript_with_explicit_keys(&this_htlc.unwrap(), &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key)
654 } else if *input_descriptor != InputDescriptors::RevokedOutput {
657 chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, self.remote_csv, &chan_keys.a_delayed_payment_key)
660 let is_htlc = *input_descriptor != InputDescriptors::RevokedOutput;
661 if let Ok(sig) = self.key_storage.sign_justice_transaction(&bumped_tx, i, &witness_script, *amount, &per_commitment_key, &chan_keys.revocation_key, is_htlc, &self.secp_ctx) {
662 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
663 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
665 bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
667 bumped_tx.input[i].witness.push(vec!(1));
669 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
670 } else { return None; }
673 log_trace!(self, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_local" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
676 &InputMaterial::RemoteHTLC { ref per_commitment_point, ref key, ref preimage, ref amount, ref locktime } => {
677 if let Ok(chan_keys) = TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, &self.remote_tx_cache.remote_delayed_payment_base_key, &self.remote_tx_cache.remote_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
678 let mut this_htlc = None;
679 if let Some(htlcs) = self.remote_tx_cache.per_htlc.get(&outp.txid) {
681 if htlc.transaction_output_index.unwrap() == outp.vout {
682 this_htlc = Some(htlc);
686 if this_htlc.is_none() { return None; }
687 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&this_htlc.unwrap(), &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key);
689 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
690 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
691 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
692 let sig = self.secp_ctx.sign(&sighash, &key);
693 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
694 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
695 if let &Some(preimage) = preimage {
696 bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
698 // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
699 bumped_tx.input[i].witness.push(vec![]);
701 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
702 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);
708 log_trace!(self, "...with timer {}", new_timer.unwrap());
709 assert!(predicted_weight >= bumped_tx.get_weight());
710 return Some((new_timer, new_feerate, bumped_tx))
712 for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
713 match per_outp_material {
714 &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
715 let htlc_tx = self.get_fully_signed_htlc_tx(outp, preimage);
716 if let Some(htlc_tx) = htlc_tx {
717 let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
718 // Timer set to $NEVER given we can't bump tx without anchor outputs
719 log_trace!(self, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
720 return Some((None, feerate, htlc_tx));
724 &InputMaterial::Funding { ref funding_redeemscript } => {
725 let signed_tx = self.get_fully_signed_local_tx(funding_redeemscript).unwrap();
726 // Timer set to $NEVER given we can't bump tx without anchor outputs
727 log_trace!(self, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
728 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
737 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)
738 where B::Target: BroadcasterInterface,
739 F::Target: FeeEstimator
741 log_trace!(self, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
742 let mut new_claims = Vec::new();
743 let mut aggregated_claim = HashMap::new();
744 let mut aggregated_soonest = ::std::u32::MAX;
746 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
747 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
748 for req in claimable_outpoints {
749 // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
750 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 {
751 log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
752 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
753 let mut single_input = HashMap::new();
754 single_input.insert(req.outpoint, req.witness_data);
755 new_claims.push((req.absolute_timelock, single_input));
757 aggregated_claim.insert(req.outpoint, req.witness_data);
758 if req.absolute_timelock < aggregated_soonest {
759 aggregated_soonest = req.absolute_timelock;
764 new_claims.push((aggregated_soonest, aggregated_claim));
766 // Generate claim transactions and track them to bump if necessary at
767 // height timer expiration (i.e in how many blocks we're going to take action).
768 for (soonest_timelock, claim) in new_claims.drain(..) {
769 let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
770 if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
771 claim_material.height_timer = new_timer;
772 claim_material.feerate_previous = new_feerate;
773 let txid = tx.txid();
774 for k in claim_material.per_input_material.keys() {
775 log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
776 self.claimable_outpoints.insert(k.clone(), (txid, height));
778 self.pending_claim_requests.insert(txid, claim_material);
779 log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
780 broadcaster.broadcast_transaction(&tx);
784 let mut bump_candidates = HashMap::new();
785 for tx in txn_matched {
786 // Scan all input to verify is one of the outpoint spent is of interest for us
787 let mut claimed_outputs_material = Vec::new();
788 for inp in &tx.input {
789 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
790 // If outpoint has claim request pending on it...
791 if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
792 //... we need to verify equality between transaction outpoints and claim request
793 // outpoints to know if transaction is the original claim or a bumped one issued
795 let mut set_equality = true;
796 if claim_material.per_input_material.len() != tx.input.len() {
797 set_equality = false;
799 for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
800 if *claim_inp != tx_inp.previous_output {
801 set_equality = false;
806 macro_rules! clean_claim_request_after_safety_delay {
808 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
809 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
810 hash_map::Entry::Occupied(mut entry) => {
811 if !entry.get().contains(&new_event) {
812 entry.get_mut().push(new_event);
815 hash_map::Entry::Vacant(entry) => {
816 entry.insert(vec![new_event]);
822 // If this is our transaction (or our counterparty spent all the outputs
823 // before we could anyway with same inputs order than us), wait for
824 // ANTI_REORG_DELAY and clean the RBF tracking map.
826 clean_claim_request_after_safety_delay!();
827 } else { // If false, generate new claim request with update outpoint set
828 let mut at_least_one_drop = false;
829 for input in tx.input.iter() {
830 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
831 claimed_outputs_material.push((input.previous_output, input_material));
832 at_least_one_drop = true;
834 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
835 if claim_material.per_input_material.is_empty() {
836 clean_claim_request_after_safety_delay!();
839 //TODO: recompute soonest_timelock to avoid wasting a bit on fees
840 if at_least_one_drop {
841 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
844 break; //No need to iterate further, either tx is our or their
846 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
850 for (outpoint, input_material) in claimed_outputs_material.drain(..) {
851 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
852 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
853 hash_map::Entry::Occupied(mut entry) => {
854 if !entry.get().contains(&new_event) {
855 entry.get_mut().push(new_event);
858 hash_map::Entry::Vacant(entry) => {
859 entry.insert(vec![new_event]);
865 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
866 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
869 OnchainEvent::Claim { claim_request } => {
870 // We may remove a whole set of claim outpoints here, as these one may have
871 // been aggregated in a single tx and claimed so atomically
872 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
873 for outpoint in bump_material.per_input_material.keys() {
874 self.claimable_outpoints.remove(&outpoint);
878 OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
879 self.claimable_outpoints.remove(&outpoint);
885 // Check if any pending claim request must be rescheduled
886 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
887 if let Some(h) = claim_data.height_timer {
889 bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
894 // Build, bump and rebroadcast tx accordingly
895 log_trace!(self, "Bumping {} candidates", bump_candidates.len());
896 for (first_claim_txid, claim_material) in bump_candidates.iter() {
897 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
898 log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
899 broadcaster.broadcast_transaction(&bump_tx);
900 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
901 claim_material.height_timer = new_timer;
902 claim_material.feerate_previous = new_feerate;
908 pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
909 where B::Target: BroadcasterInterface,
910 F::Target: FeeEstimator
912 let mut bump_candidates = HashMap::new();
913 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
914 //- our claim tx on a commitment tx output
915 //- resurect outpoint back in its claimable set and regenerate tx
918 OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
919 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
920 if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
921 claim_material.per_input_material.insert(outpoint, input_material);
922 // Using a HashMap guarantee us than if we have multiple outpoints getting
923 // resurrected only one bump claim tx is going to be broadcast
924 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
932 for (_, claim_material) in bump_candidates.iter_mut() {
933 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
934 claim_material.height_timer = new_timer;
935 claim_material.feerate_previous = new_feerate;
936 broadcaster.broadcast_transaction(&bump_tx);
939 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
940 self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
942 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
943 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
944 let mut remove_request = Vec::new();
945 self.claimable_outpoints.retain(|_, ref v|
947 remove_request.push(v.0.clone());
950 for req in remove_request {
951 self.pending_claim_requests.remove(&req);
955 pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
956 // To prevent any unsafe state discrepancy between offchain and onchain, once local
957 // commitment transaction has been signed due to an event (either block height for
958 // HTLC-timeout or channel force-closure), don't allow any further update of local
959 // commitment transaction view to avoid delivery of revocation secret to counterparty
960 // for the aformentionned signed transaction.
961 if self.local_htlc_sigs.is_some() || self.prev_local_htlc_sigs.is_some() {
964 self.prev_local_commitment = self.local_commitment.take();
965 self.local_commitment = Some(tx);
969 fn sign_latest_local_htlcs(&mut self) {
970 if let Some(ref local_commitment) = self.local_commitment {
971 if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
972 self.local_htlc_sigs = Some(Vec::new());
973 let ret = self.local_htlc_sigs.as_mut().unwrap();
974 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
975 if let Some(tx_idx) = htlc.transaction_output_index {
976 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
977 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
979 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
985 fn sign_prev_local_htlcs(&mut self) {
986 if let Some(ref local_commitment) = self.prev_local_commitment {
987 if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
988 self.prev_local_htlc_sigs = Some(Vec::new());
989 let ret = self.prev_local_htlc_sigs.as_mut().unwrap();
990 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
991 if let Some(tx_idx) = htlc.transaction_output_index {
992 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
993 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
995 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
1002 //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
1003 // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
1004 // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
1005 // to monitor before.
1006 pub(super) fn get_fully_signed_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
1007 if let Some(ref mut local_commitment) = self.local_commitment {
1008 match self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx) {
1009 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
1010 Err(_) => return None,
1017 pub(super) fn provide_latest_remote_tx(&mut self, commitment_txid: Txid, htlcs: Vec<HTLCOutputInCommitment>) {
1018 self.remote_tx_cache.per_htlc.insert(commitment_txid, htlcs);
1022 pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
1023 if let Some(ref mut local_commitment) = self.local_commitment {
1024 let local_commitment = local_commitment.clone();
1025 match self.key_storage.sign_local_commitment(&local_commitment, &self.secp_ctx) {
1026 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
1027 Err(_) => return None,
1034 pub(super) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1035 let mut htlc_tx = None;
1036 if self.local_commitment.is_some() {
1037 let commitment_txid = self.local_commitment.as_ref().unwrap().txid();
1038 if commitment_txid == outp.txid {
1039 self.sign_latest_local_htlcs();
1040 if let &Some(ref htlc_sigs) = &self.local_htlc_sigs {
1041 let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1042 htlc_tx = Some(self.local_commitment.as_ref().unwrap()
1043 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
1047 if self.prev_local_commitment.is_some() {
1048 let commitment_txid = self.prev_local_commitment.as_ref().unwrap().txid();
1049 if commitment_txid == outp.txid {
1050 self.sign_prev_local_htlcs();
1051 if let &Some(ref htlc_sigs) = &self.prev_local_htlc_sigs {
1052 let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1053 htlc_tx = Some(self.prev_local_commitment.as_ref().unwrap()
1054 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
1062 pub(super) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1063 let latest_had_sigs = self.local_htlc_sigs.is_some();
1064 let prev_had_sigs = self.prev_local_htlc_sigs.is_some();
1065 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
1066 if !latest_had_sigs {
1067 self.local_htlc_sigs = None;
1070 self.prev_local_htlc_sigs = None;