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, Signature};
16 use ln::msgs::DecodeError;
17 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
18 use ln::channelmanager::{HTLCSource, PaymentPreimage};
20 use ln::chan_utils::{HTLCType, LocalCommitmentTransaction, TxCreationKeys, HTLCOutputInCommitment};
21 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
22 use chain::keysinterface::ChannelKeys;
23 use util::logger::Logger;
24 use util::ser::{ReadableArgs, Readable, Writer, Writeable};
27 use std::collections::{HashMap, hash_map, HashSet};
32 const MAX_ALLOC_SIZE: usize = 64*1024;
34 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
35 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
36 #[derive(Clone, PartialEq)]
38 /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
39 /// bump-txn candidate buffer.
41 claim_request: Sha256dHash,
43 /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
44 /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
45 /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
47 outpoint: BitcoinOutPoint,
48 input_material: InputMaterial,
52 /// Cache public keys and feerate used to compute any HTLC transaction.
53 /// We only keep state for latest 2 commitment transactions as we should
54 /// never have to generate HTLC txn for revoked local commitment
56 local_keys: TxCreationKeys,
58 per_htlc: HashMap<u32, (HTLCOutputInCommitment, Option<Signature>)>
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 })
107 pub(super) 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 macro_rules! subtract_high_prio_fee {
116 ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
118 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
119 let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
121 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
122 fee = $used_feerate * ($predicted_weight as u64) / 1000;
124 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
125 fee = $used_feerate * ($predicted_weight as u64) / 1000;
127 log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
131 log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
137 log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
151 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
152 /// do RBF bumping if possible.
153 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
154 destination_script: Script,
155 funding_redeemscript: Script,
156 local_commitment: Option<LocalCommitmentTransaction>,
157 prev_local_commitment: Option<LocalCommitmentTransaction>,
158 current_htlc_cache: Option<HTLCTxCache>,
159 prev_htlc_cache: Option<HTLCTxCache>,
162 key_storage: ChanSigner,
164 // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
165 // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
166 // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
167 // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
168 // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
169 // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
170 // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
171 // we need to regenerate new claim request with reduced set of still-claimable outpoints.
172 // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
173 // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
174 // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
175 #[cfg(test)] // Used in functional_test to verify sanitization
176 pub pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
178 pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
180 // Used to link outpoints claimed in a connected block to a pending claim request.
181 // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
182 // Value is (pending claim request identifier, confirmation_block), identifier
183 // is txid of the initial claiming transaction and is immutable until outpoint is
184 // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
185 // block with output gets disconnected.
186 #[cfg(test)] // Used in functional_test to verify sanitization
187 pub claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
189 claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
191 onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
193 secp_ctx: Secp256k1<secp256k1::All>,
197 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
198 pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
199 self.destination_script.write(writer)?;
200 self.funding_redeemscript.write(writer)?;
201 self.local_commitment.write(writer)?;
202 self.prev_local_commitment.write(writer)?;
204 macro_rules! serialize_htlc_cache {
206 $cache.local_keys.write(writer)?;
207 $cache.feerate_per_kw.write(writer)?;
208 writer.write_all(&byte_utils::be64_to_array($cache.per_htlc.len() as u64))?;
209 for (_, &(ref htlc, ref sig)) in $cache.per_htlc.iter() {
211 if let &Some(ref their_sig) = sig {
213 writer.write_all(&their_sig.serialize_compact())?;
221 if let Some(ref current) = self.current_htlc_cache {
222 writer.write_all(&[1; 1])?;
223 serialize_htlc_cache!(current);
225 writer.write_all(&[0; 1])?;
228 if let Some(ref prev) = self.prev_htlc_cache {
229 writer.write_all(&[1; 1])?;
230 serialize_htlc_cache!(prev);
232 writer.write_all(&[0; 1])?;
234 self.local_csv.write(writer)?;
236 self.key_storage.write(writer)?;
238 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
239 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
240 ancestor_claim_txid.write(writer)?;
241 claim_tx_data.write(writer)?;
244 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
245 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
247 claim_and_height.0.write(writer)?;
248 claim_and_height.1.write(writer)?;
251 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
252 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
253 writer.write_all(&byte_utils::be32_to_array(**target))?;
254 writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
255 for ev in events.iter() {
257 OnchainEvent::Claim { ref claim_request } => {
258 writer.write_all(&[0; 1])?;
259 claim_request.write(writer)?;
261 OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
262 writer.write_all(&[1; 1])?;
263 outpoint.write(writer)?;
264 input_material.write(writer)?;
273 impl<ChanSigner: ChannelKeys + Readable> ReadableArgs<Arc<Logger>> for OnchainTxHandler<ChanSigner> {
274 fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
275 let destination_script = Readable::read(reader)?;
276 let funding_redeemscript = Readable::read(reader)?;
277 let local_commitment = Readable::read(reader)?;
278 let prev_local_commitment = Readable::read(reader)?;
280 macro_rules! read_htlc_cache {
283 let local_keys = Readable::read(reader)?;
284 let feerate_per_kw = Readable::read(reader)?;
285 let htlcs_count: u64 = Readable::read(reader)?;
286 let mut per_htlc = HashMap::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
287 for _ in 0..htlcs_count {
288 let htlc: HTLCOutputInCommitment = Readable::read(reader)?;
289 let sigs = match <u8 as Readable>::read(reader)? {
291 1 => Some(Readable::read(reader)?),
292 _ => return Err(DecodeError::InvalidValue),
294 per_htlc.insert(htlc.transaction_output_index.unwrap(), (htlc, sigs));
305 let current_htlc_cache = match <u8 as Readable>::read(reader)? {
308 Some(read_htlc_cache!())
310 _ => return Err(DecodeError::InvalidValue),
313 let prev_htlc_cache = match <u8 as Readable>::read(reader)? {
316 Some(read_htlc_cache!())
318 _ => return Err(DecodeError::InvalidValue),
320 let local_csv = Readable::read(reader)?;
322 let key_storage = Readable::read(reader)?;
324 let pending_claim_requests_len: u64 = Readable::read(reader)?;
325 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
326 for _ in 0..pending_claim_requests_len {
327 pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
330 let claimable_outpoints_len: u64 = Readable::read(reader)?;
331 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
332 for _ in 0..claimable_outpoints_len {
333 let outpoint = Readable::read(reader)?;
334 let ancestor_claim_txid = Readable::read(reader)?;
335 let height = Readable::read(reader)?;
336 claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
338 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
339 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
340 for _ in 0..waiting_threshold_conf_len {
341 let height_target = Readable::read(reader)?;
342 let events_len: u64 = Readable::read(reader)?;
343 let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
344 for _ in 0..events_len {
345 let ev = match <u8 as Readable>::read(reader)? {
347 let claim_request = Readable::read(reader)?;
348 OnchainEvent::Claim {
353 let outpoint = Readable::read(reader)?;
354 let input_material = Readable::read(reader)?;
355 OnchainEvent::ContentiousOutpoint {
360 _ => return Err(DecodeError::InvalidValue),
364 onchain_events_waiting_threshold_conf.insert(height_target, events);
367 Ok(OnchainTxHandler {
369 funding_redeemscript,
371 prev_local_commitment,
377 pending_claim_requests,
378 onchain_events_waiting_threshold_conf,
379 secp_ctx: Secp256k1::new(),
385 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
386 pub(super) fn new(destination_script: Script, keys: ChanSigner, funding_redeemscript: Script, local_csv: u16, logger: Arc<Logger>) -> Self {
388 let key_storage = keys;
392 funding_redeemscript,
393 local_commitment: None,
394 prev_local_commitment: None,
395 current_htlc_cache: None,
396 prev_htlc_cache: None,
399 pending_claim_requests: HashMap::new(),
400 claimable_outpoints: HashMap::new(),
401 onchain_events_waiting_threshold_conf: HashMap::new(),
403 secp_ctx: Secp256k1::new(),
408 pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
409 let mut tx_weight = 2; // count segwit flags
411 // We use expected weight (and not actual) as signatures and time lock delays may vary
412 tx_weight += match inp {
413 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
414 &InputDescriptors::RevokedOfferedHTLC => {
415 1 + 1 + 73 + 1 + 33 + 1 + 133
417 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
418 &InputDescriptors::RevokedReceivedHTLC => {
419 1 + 1 + 73 + 1 + 33 + 1 + 139
421 // number_of_witness_elements + sig_length + remotehtlc_sig + preimage_length + preimage + witness_script_length + witness_script
422 &InputDescriptors::OfferedHTLC => {
423 1 + 1 + 73 + 1 + 32 + 1 + 133
425 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
426 &InputDescriptors::ReceivedHTLC => {
427 1 + 1 + 73 + 1 + 1 + 1 + 139
429 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
430 &InputDescriptors::RevokedOutput => {
431 1 + 1 + 73 + 1 + 1 + 1 + 77
438 /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
439 /// 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
440 /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
441 /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
442 /// frequency of the bump and so increase our bets of success.
443 fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
444 if timelock_expiration <= current_height + 3 {
445 return current_height + 1
446 } else if timelock_expiration - current_height <= 15 {
447 return current_height + 3
452 /// 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
453 /// (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.
454 fn generate_claim_tx<F: Deref>(&self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(Option<u32>, u64, Transaction)>
455 where F::Target: FeeEstimator
457 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
458 let mut inputs = Vec::new();
459 for outp in cached_claim_datas.per_input_material.keys() {
460 log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
462 previous_output: *outp,
463 script_sig: Script::new(),
464 sequence: 0xfffffffd,
468 let mut bumped_tx = Transaction {
473 script_pubkey: self.destination_script.clone(),
478 macro_rules! RBF_bump {
479 ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
481 let mut used_feerate;
482 // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
483 let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
484 let mut value = $amount;
485 if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
486 // Overflow check is done in subtract_high_prio_fee
489 log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
492 // ...else just increase the previous feerate by 25% (because that's a nice number)
494 let fee = $old_feerate * $predicted_weight / 750;
496 log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
502 let previous_fee = $old_feerate * $predicted_weight / 1000;
503 let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
504 // BIP 125 Opt-in Full Replace-by-Fee Signaling
505 // * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
506 // * 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.
507 let new_fee = if new_fee < previous_fee + min_relay_fee {
508 new_fee + previous_fee + min_relay_fee - new_fee
512 Some((new_fee, new_fee * 1000 / $predicted_weight))
517 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
518 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
519 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
520 let mut inputs_witnesses_weight = 0;
522 let mut dynamic_fee = true;
523 for per_outp_material in cached_claim_datas.per_input_material.values() {
524 match per_outp_material {
525 &InputMaterial::Revoked { ref witness_script, ref is_htlc, ref amount, .. } => {
526 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!() });
529 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
530 inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
533 &InputMaterial::LocalHTLC { .. } => { return None; }
534 &InputMaterial::Funding { .. } => {
541 let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
543 // If old feerate is 0, first iteration of this claim, use normal fee calculation
544 if cached_claim_datas.feerate_previous != 0 {
545 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
546 // If new computed fee is superior at the whole claimable amount burn all in fees
548 bumped_tx.output[0].value = 0;
550 bumped_tx.output[0].value = amt - new_fee;
552 new_feerate = feerate;
553 } else { return None; }
555 if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
556 bumped_tx.output[0].value = amt;
557 } else { return None; }
559 assert!(new_feerate != 0);
561 for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
562 match per_outp_material {
563 &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref is_htlc, ref amount } => {
564 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
565 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
566 let sig = self.secp_ctx.sign(&sighash, &key);
567 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
568 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
570 bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
572 bumped_tx.input[i].witness.push(vec!(1));
574 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
575 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);
577 &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
578 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
579 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
580 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
581 let sig = self.secp_ctx.sign(&sighash, &key);
582 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
583 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
584 if let &Some(preimage) = preimage {
585 bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
587 bumped_tx.input[i].witness.push(vec![]);
589 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
590 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);
595 log_trace!(self, "...with timer {}", new_timer.unwrap());
596 assert!(predicted_weight >= bumped_tx.get_weight());
597 return Some((new_timer, new_feerate, bumped_tx))
599 for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
600 match per_outp_material {
601 &InputMaterial::LocalHTLC { .. } => {
602 //TODO : Given that Local Commitment Transaction and HTLC-Timeout/HTLC-Success are counter-signed by peer, we can't
603 // RBF them. Need a Lightning specs change and package relay modification :
604 // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
607 &InputMaterial::Funding { ref channel_value } => {
608 if self.local_commitment.is_some() {
609 let mut local_commitment = self.local_commitment.clone().unwrap();
610 self.key_storage.sign_local_commitment(&mut local_commitment, &self.funding_redeemscript, *channel_value, &self.secp_ctx);
611 let signed_tx = local_commitment.with_valid_witness().clone();
612 let mut amt_outputs = 0;
613 for outp in signed_tx.output.iter() {
614 amt_outputs += outp.value;
616 let feerate = (channel_value - amt_outputs) * 1000 / signed_tx.get_weight() as u64;
617 // Timer set to $NEVER given we can't bump tx without anchor outputs
618 log_trace!(self, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
619 return Some((None, feerate, signed_tx));
629 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)
630 where B::Target: BroadcasterInterface,
631 F::Target: FeeEstimator
633 log_trace!(self, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
634 let mut new_claims = Vec::new();
635 let mut aggregated_claim = HashMap::new();
636 let mut aggregated_soonest = ::std::u32::MAX;
638 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
639 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
640 for req in claimable_outpoints {
641 // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
642 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 {
643 log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
644 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
645 let mut single_input = HashMap::new();
646 single_input.insert(req.outpoint, req.witness_data);
647 new_claims.push((req.absolute_timelock, single_input));
649 aggregated_claim.insert(req.outpoint, req.witness_data);
650 if req.absolute_timelock < aggregated_soonest {
651 aggregated_soonest = req.absolute_timelock;
656 new_claims.push((aggregated_soonest, aggregated_claim));
658 // Generate claim transactions and track them to bump if necessary at
659 // height timer expiration (i.e in how many blocks we're going to take action).
660 for claim in new_claims {
661 let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock: claim.0, per_input_material: claim.1.clone() };
662 if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
663 claim_material.height_timer = new_timer;
664 claim_material.feerate_previous = new_feerate;
665 let txid = tx.txid();
666 self.pending_claim_requests.insert(txid, claim_material);
667 for k in claim.1.keys() {
668 log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
669 self.claimable_outpoints.insert(k.clone(), (txid, height));
671 log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
672 broadcaster.broadcast_transaction(&tx);
676 let mut bump_candidates = HashSet::new();
677 for tx in txn_matched {
678 // Scan all input to verify is one of the outpoint spent is of interest for us
679 let mut claimed_outputs_material = Vec::new();
680 for inp in &tx.input {
681 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
682 // If outpoint has claim request pending on it...
683 if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
684 //... we need to verify equality between transaction outpoints and claim request
685 // outpoints to know if transaction is the original claim or a bumped one issued
687 let mut set_equality = true;
688 if claim_material.per_input_material.len() != tx.input.len() {
689 set_equality = false;
691 for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
692 if *claim_inp != tx_inp.previous_output {
693 set_equality = false;
698 macro_rules! clean_claim_request_after_safety_delay {
700 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
701 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
702 hash_map::Entry::Occupied(mut entry) => {
703 if !entry.get().contains(&new_event) {
704 entry.get_mut().push(new_event);
707 hash_map::Entry::Vacant(entry) => {
708 entry.insert(vec![new_event]);
714 // If this is our transaction (or our counterparty spent all the outputs
715 // before we could anyway with same inputs order than us), wait for
716 // ANTI_REORG_DELAY and clean the RBF tracking map.
718 clean_claim_request_after_safety_delay!();
719 } else { // If false, generate new claim request with update outpoint set
720 let mut at_least_one_drop = false;
721 for input in tx.input.iter() {
722 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
723 claimed_outputs_material.push((input.previous_output, input_material));
724 at_least_one_drop = true;
726 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
727 if claim_material.per_input_material.is_empty() {
728 clean_claim_request_after_safety_delay!();
731 //TODO: recompute soonest_timelock to avoid wasting a bit on fees
732 if at_least_one_drop {
733 bump_candidates.insert(first_claim_txid_height.0.clone());
736 break; //No need to iterate further, either tx is our or their
738 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
742 for (outpoint, input_material) in claimed_outputs_material.drain(..) {
743 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
744 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
745 hash_map::Entry::Occupied(mut entry) => {
746 if !entry.get().contains(&new_event) {
747 entry.get_mut().push(new_event);
750 hash_map::Entry::Vacant(entry) => {
751 entry.insert(vec![new_event]);
757 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
758 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
761 OnchainEvent::Claim { claim_request } => {
762 // We may remove a whole set of claim outpoints here, as these one may have
763 // been aggregated in a single tx and claimed so atomically
764 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
765 for outpoint in bump_material.per_input_material.keys() {
766 self.claimable_outpoints.remove(&outpoint);
770 OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
771 self.claimable_outpoints.remove(&outpoint);
777 // Check if any pending claim request must be rescheduled
778 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
779 if let Some(h) = claim_data.height_timer {
781 bump_candidates.insert(*first_claim_txid);
786 // Build, bump and rebroadcast tx accordingly
787 log_trace!(self, "Bumping {} candidates", bump_candidates.len());
788 for first_claim_txid in bump_candidates.iter() {
789 if let Some((new_timer, new_feerate)) = {
790 if let Some(claim_material) = self.pending_claim_requests.get(first_claim_txid) {
791 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
792 log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
793 broadcaster.broadcast_transaction(&bump_tx);
794 Some((new_timer, new_feerate))
796 } else { unreachable!(); }
798 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
799 claim_material.height_timer = new_timer;
800 claim_material.feerate_previous = new_feerate;
801 } else { unreachable!(); }
806 pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
807 where B::Target: BroadcasterInterface,
808 F::Target: FeeEstimator
810 let mut bump_candidates = HashMap::new();
811 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
812 //- our claim tx on a commitment tx output
813 //- resurect outpoint back in its claimable set and regenerate tx
816 OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
817 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
818 if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
819 claim_material.per_input_material.insert(outpoint, input_material);
820 // Using a HashMap guarantee us than if we have multiple outpoints getting
821 // resurrected only one bump claim tx is going to be broadcast
822 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
830 for (_, claim_material) in bump_candidates.iter_mut() {
831 if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
832 claim_material.height_timer = new_timer;
833 claim_material.feerate_previous = new_feerate;
834 broadcaster.broadcast_transaction(&bump_tx);
837 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
838 self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
840 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
841 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
842 let mut remove_request = Vec::new();
843 self.claimable_outpoints.retain(|_, ref v|
845 remove_request.push(v.0.clone());
848 for req in remove_request {
849 self.pending_claim_requests.remove(&req);
853 pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction, local_keys: chan_utils::TxCreationKeys, feerate_per_kw: u64, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), ()> {
854 // To prevent any unsafe state discrepancy between offchain and onchain, once local
855 // commitment transaction has been signed due to an event (either block height for
856 // HTLC-timeout or channel force-closure), don't allow any further update of local
857 // commitment transaction view to avoid delivery of revocation secret to counterparty
858 // for the aformentionned signed transaction.
859 if let Some(ref local_commitment) = self.local_commitment {
860 if local_commitment.has_local_sig() { return Err(()) }
862 self.prev_local_commitment = self.local_commitment.take();
863 self.local_commitment = Some(tx);
864 self.prev_htlc_cache = self.current_htlc_cache.take();
865 let mut per_htlc = HashMap::with_capacity(htlc_outputs.len());
866 for htlc in htlc_outputs {
867 if htlc.0.transaction_output_index.is_some() { // Discard dust HTLC as we will never have to generate onchain tx for them
868 per_htlc.insert(htlc.0.transaction_output_index.unwrap(), (htlc.0, htlc.1));
871 self.current_htlc_cache = Some(HTLCTxCache {
879 pub(super) fn get_fully_signed_local_tx(&mut self, channel_value_satoshis: u64) -> Option<Transaction> {
880 if let Some(ref mut local_commitment) = self.local_commitment {
881 self.key_storage.sign_local_commitment(local_commitment, &self.funding_redeemscript, channel_value_satoshis, &self.secp_ctx);
882 return Some(local_commitment.with_valid_witness().clone());
888 pub(super) fn get_fully_signed_copy_local_tx(&mut self, channel_value_satoshis: u64) -> Option<Transaction> {
889 if let Some(ref mut local_commitment) = self.local_commitment {
890 let mut local_commitment = local_commitment.clone();
891 self.key_storage.unsafe_sign_local_commitment(&mut local_commitment, &self.funding_redeemscript, channel_value_satoshis, &self.secp_ctx);
892 return Some(local_commitment.with_valid_witness().clone());
897 pub(super) fn get_fully_signed_htlc_tx(&mut self, txid: Sha256dHash, htlc_index: u32, preimage: Option<PaymentPreimage>) -> Option<Transaction> {
898 //TODO: store preimage in OnchainTxHandler
899 if let Some(ref local_commitment) = self.local_commitment {
900 if local_commitment.txid() == txid {
901 if let Some(ref htlc_cache) = self.current_htlc_cache {
902 if let Some(htlc) = htlc_cache.per_htlc.get(&htlc_index) {
903 if !htlc.0.offered && preimage.is_none() { return None; }; // If we don't have preimage for HTLC-Success, don't try to generate
904 let htlc_secret = if !htlc.0.offered { preimage } else { None }; // If we have a preimage for a HTLC-Timeout, don't use it that's likely a duplicate HTLC hash
905 let mut htlc_tx = chan_utils::build_htlc_transaction(&txid, htlc_cache.feerate_per_kw, self.local_csv, &htlc.0, &htlc_cache.local_keys.a_delayed_payment_key, &htlc_cache.local_keys.revocation_key);
906 self.key_storage.sign_htlc_transaction(&mut htlc_tx, htlc.1.as_ref().unwrap(), &htlc_secret, &htlc.0, &htlc_cache.local_keys.a_htlc_key, &htlc_cache.local_keys.b_htlc_key, &htlc_cache.local_keys.revocation_key, &htlc_cache.local_keys.per_commitment_point, &self.secp_ctx);
907 return Some(htlc_tx);