1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Various utilities to assemble claimable outpoints in package of one or more transactions. Those
11 //! packages are attached metadata, guiding their aggregable or fee-bumping re-schedule. This file
12 //! also includes witness weight computation and fee computation methods.
14 use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
15 use bitcoin::blockdata::transaction::{TxOut,TxIn, Transaction, SigHashType};
16 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
17 use bitcoin::blockdata::script::Script;
19 use bitcoin::hash_types::Txid;
21 use bitcoin::secp256k1::key::{SecretKey,PublicKey};
23 use ln::PaymentPreimage;
24 use ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment};
26 use ln::msgs::DecodeError;
27 use chain::chaininterface::{FeeEstimator, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
28 use chain::keysinterface::Sign;
29 use chain::onchaintx::OnchainTxHandler;
31 use util::logger::Logger;
32 use util::ser::{Readable, Writer, Writeable};
38 const MAX_ALLOC_SIZE: usize = 64*1024;
41 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
42 pub(crate) const WEIGHT_REVOKED_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 + 133;
43 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
44 pub(crate) const WEIGHT_REVOKED_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 + 139;
45 // number_of_witness_elements + sig_length + counterpartyhtlc_sig + preimage_length + preimage + witness_script_length + witness_script
46 pub(crate) const WEIGHT_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 32 + 1 + 133;
47 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
48 pub(crate) const WEIGHT_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 139;
49 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
50 pub(crate) const WEIGHT_REVOKED_OUTPUT: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 77;
52 /// Height delay at which transactions are fee-bumped/rebroadcasted with a low priority.
53 const LOW_FREQUENCY_BUMP_INTERVAL: u32 = 15;
54 /// Height delay at which transactions are fee-bumped/rebroadcasted with a middle priority.
55 const MIDDLE_FREQUENCY_BUMP_INTERVAL: u32 = 3;
56 /// Height delay at which transactions are fee-bumped/rebroadcasted with a high priority.
57 const HIGH_FREQUENCY_BUMP_INTERVAL: u32 = 1;
59 /// A struct to describe a revoked output and corresponding information to generate a solving
60 /// witness spending a commitment `to_local` output or a second-stage HTLC transaction output.
62 /// CSV and pubkeys are used as part of a witnessScript redeeming a balance output, amount is used
63 /// as part of the signature hash and revocation secret to generate a satisfying witness.
64 #[derive(Clone, PartialEq)]
65 pub(crate) struct RevokedOutput {
66 per_commitment_point: PublicKey,
67 counterparty_delayed_payment_base_key: PublicKey,
68 counterparty_htlc_base_key: PublicKey,
69 per_commitment_key: SecretKey,
72 on_counterparty_tx_csv: u16,
76 pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, per_commitment_key: SecretKey, amount: u64, on_counterparty_tx_csv: u16) -> Self {
79 counterparty_delayed_payment_base_key,
80 counterparty_htlc_base_key,
82 weight: WEIGHT_REVOKED_OUTPUT,
84 on_counterparty_tx_csv
89 impl_writeable_tlv_based!(RevokedOutput, {
90 (0, per_commitment_point, required),
91 (2, counterparty_delayed_payment_base_key, required),
92 (4, counterparty_htlc_base_key, required),
93 (6, per_commitment_key, required),
94 (8, weight, required),
95 (10, amount, required),
96 (12, on_counterparty_tx_csv, required),
99 /// A struct to describe a revoked offered output and corresponding information to generate a
102 /// HTLCOuputInCommitment (hash timelock, direction) and pubkeys are used to generate a suitable
105 /// CSV is used as part of a witnessScript redeeming a balance output, amount is used as part
106 /// of the signature hash and revocation secret to generate a satisfying witness.
107 #[derive(Clone, PartialEq)]
108 pub(crate) struct RevokedHTLCOutput {
109 per_commitment_point: PublicKey,
110 counterparty_delayed_payment_base_key: PublicKey,
111 counterparty_htlc_base_key: PublicKey,
112 per_commitment_key: SecretKey,
115 htlc: HTLCOutputInCommitment,
118 impl RevokedHTLCOutput {
119 pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, per_commitment_key: SecretKey, amount: u64, htlc: HTLCOutputInCommitment) -> Self {
120 let weight = if htlc.offered { WEIGHT_REVOKED_OFFERED_HTLC } else { WEIGHT_REVOKED_RECEIVED_HTLC };
122 per_commitment_point,
123 counterparty_delayed_payment_base_key,
124 counterparty_htlc_base_key,
133 impl_writeable_tlv_based!(RevokedHTLCOutput, {
134 (0, per_commitment_point, required),
135 (2, counterparty_delayed_payment_base_key, required),
136 (4, counterparty_htlc_base_key, required),
137 (6, per_commitment_key, required),
138 (8, weight, required),
139 (10, amount, required),
140 (12, htlc, required),
143 /// A struct to describe a HTLC output on a counterparty commitment transaction.
145 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
148 /// The preimage is used as part of the witness.
149 #[derive(Clone, PartialEq)]
150 pub(crate) struct CounterpartyOfferedHTLCOutput {
151 per_commitment_point: PublicKey,
152 counterparty_delayed_payment_base_key: PublicKey,
153 counterparty_htlc_base_key: PublicKey,
154 preimage: PaymentPreimage,
155 htlc: HTLCOutputInCommitment
158 impl CounterpartyOfferedHTLCOutput {
159 pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, preimage: PaymentPreimage, htlc: HTLCOutputInCommitment) -> Self {
160 CounterpartyOfferedHTLCOutput {
161 per_commitment_point,
162 counterparty_delayed_payment_base_key,
163 counterparty_htlc_base_key,
170 impl_writeable_tlv_based!(CounterpartyOfferedHTLCOutput, {
171 (0, per_commitment_point, required),
172 (2, counterparty_delayed_payment_base_key, required),
173 (4, counterparty_htlc_base_key, required),
174 (6, preimage, required),
178 /// A struct to describe a HTLC output on a counterparty commitment transaction.
180 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
182 #[derive(Clone, PartialEq)]
183 pub(crate) struct CounterpartyReceivedHTLCOutput {
184 per_commitment_point: PublicKey,
185 counterparty_delayed_payment_base_key: PublicKey,
186 counterparty_htlc_base_key: PublicKey,
187 htlc: HTLCOutputInCommitment
190 impl CounterpartyReceivedHTLCOutput {
191 pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, htlc: HTLCOutputInCommitment) -> Self {
192 CounterpartyReceivedHTLCOutput {
193 per_commitment_point,
194 counterparty_delayed_payment_base_key,
195 counterparty_htlc_base_key,
201 impl_writeable_tlv_based!(CounterpartyReceivedHTLCOutput, {
202 (0, per_commitment_point, required),
203 (2, counterparty_delayed_payment_base_key, required),
204 (4, counterparty_htlc_base_key, required),
208 /// A struct to describe a HTLC output on holder commitment transaction.
210 /// Either offered or received, the amount is always used as part of the bip143 sighash.
211 /// Preimage is only included as part of the witness in former case.
212 #[derive(Clone, PartialEq)]
213 pub(crate) struct HolderHTLCOutput {
214 preimage: Option<PaymentPreimage>,
216 /// Defaults to 0 for HTLC-Success transactions, which have no expiry
220 impl HolderHTLCOutput {
221 pub(crate) fn build_offered(amount: u64, cltv_expiry: u32) -> Self {
229 pub(crate) fn build_accepted(preimage: PaymentPreimage, amount: u64) -> Self {
231 preimage: Some(preimage),
238 impl_writeable_tlv_based!(HolderHTLCOutput, {
239 (0, amount, required),
240 (2, cltv_expiry, required),
241 (4, preimage, option)
244 /// A struct to describe the channel output on the funding transaction.
246 /// witnessScript is used as part of the witness redeeming the funding utxo.
247 #[derive(Clone, PartialEq)]
248 pub(crate) struct HolderFundingOutput {
249 funding_redeemscript: Script,
252 impl HolderFundingOutput {
253 pub(crate) fn build(funding_redeemscript: Script) -> Self {
254 HolderFundingOutput {
255 funding_redeemscript,
260 impl_writeable_tlv_based!(HolderFundingOutput, {
261 (0, funding_redeemscript, required),
264 /// A wrapper encapsulating all in-protocol differing outputs types.
266 /// The generic API offers access to an outputs common attributes or allow transformation such as
267 /// finalizing an input claiming the output.
268 #[derive(Clone, PartialEq)]
269 pub(crate) enum PackageSolvingData {
270 RevokedOutput(RevokedOutput),
271 RevokedHTLCOutput(RevokedHTLCOutput),
272 CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput),
273 CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput),
274 HolderHTLCOutput(HolderHTLCOutput),
275 HolderFundingOutput(HolderFundingOutput),
278 impl PackageSolvingData {
279 fn amount(&self) -> u64 {
280 let amt = match self {
281 PackageSolvingData::RevokedOutput(ref outp) => { outp.amount },
282 PackageSolvingData::RevokedHTLCOutput(ref outp) => { outp.amount },
283 PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => { outp.htlc.amount_msat / 1000 },
284 PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => { outp.htlc.amount_msat / 1000 },
285 // Note: Currently, amounts of holder outputs spending witnesses aren't used
286 // as we can't malleate spending package to increase their feerate. This
287 // should change with the remaining anchor output patchset.
288 PackageSolvingData::HolderHTLCOutput(..) => { unreachable!() },
289 PackageSolvingData::HolderFundingOutput(..) => { unreachable!() },
293 fn weight(&self) -> usize {
294 let weight = match self {
295 PackageSolvingData::RevokedOutput(ref outp) => { outp.weight as usize },
296 PackageSolvingData::RevokedHTLCOutput(ref outp) => { outp.weight as usize },
297 PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { WEIGHT_OFFERED_HTLC as usize },
298 PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { WEIGHT_RECEIVED_HTLC as usize },
299 // Note: Currently, weights of holder outputs spending witnesses aren't used
300 // as we can't malleate spending package to increase their feerate. This
301 // should change with the remaining anchor output patchset.
302 PackageSolvingData::HolderHTLCOutput(..) => { unreachable!() },
303 PackageSolvingData::HolderFundingOutput(..) => { unreachable!() },
307 fn is_compatible(&self, input: &PackageSolvingData) -> bool {
309 PackageSolvingData::RevokedOutput(..) => {
311 PackageSolvingData::RevokedHTLCOutput(..) => { true },
312 PackageSolvingData::RevokedOutput(..) => { true },
316 PackageSolvingData::RevokedHTLCOutput(..) => {
318 PackageSolvingData::RevokedOutput(..) => { true },
319 PackageSolvingData::RevokedHTLCOutput(..) => { true },
323 _ => { mem::discriminant(self) == mem::discriminant(&input) }
326 fn finalize_input<Signer: Sign>(&self, bumped_tx: &mut Transaction, i: usize, onchain_handler: &mut OnchainTxHandler<Signer>) -> bool {
328 PackageSolvingData::RevokedOutput(ref outp) => {
329 if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) {
330 let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key);
331 //TODO: should we panic on signer failure ?
332 if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) {
333 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
334 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
335 bumped_tx.input[i].witness.push(vec!(1));
336 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
337 } else { return false; }
340 PackageSolvingData::RevokedHTLCOutput(ref outp) => {
341 if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) {
342 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
343 //TODO: should we panic on signer failure ?
344 if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_htlc(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &outp.htlc, &onchain_handler.secp_ctx) {
345 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
346 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
347 bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
348 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
349 } else { return false; }
352 PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => {
353 if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) {
354 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
356 if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) {
357 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
358 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
359 bumped_tx.input[i].witness.push(outp.preimage.0.to_vec());
360 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
364 PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => {
365 if let Ok(chan_keys) = TxCreationKeys::derive_new(&onchain_handler.secp_ctx, &outp.per_commitment_point, &outp.counterparty_delayed_payment_base_key, &outp.counterparty_htlc_base_key, &onchain_handler.signer.pubkeys().revocation_basepoint, &onchain_handler.signer.pubkeys().htlc_basepoint) {
366 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
368 bumped_tx.lock_time = outp.htlc.cltv_expiry; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation
369 if let Ok(sig) = onchain_handler.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &outp.htlc.amount_msat / 1000, &outp.per_commitment_point, &outp.htlc, &onchain_handler.secp_ctx) {
370 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
371 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
372 // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
373 bumped_tx.input[i].witness.push(vec![]);
374 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
378 _ => { panic!("API Error!"); }
382 fn get_finalized_tx<Signer: Sign>(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler<Signer>) -> Option<Transaction> {
384 PackageSolvingData::HolderHTLCOutput(ref outp) => { return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage); }
385 PackageSolvingData::HolderFundingOutput(ref outp) => { return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript)); }
386 _ => { panic!("API Error!"); }
389 fn absolute_tx_timelock(&self, output_conf_height: u32) -> u32 {
390 // Get the absolute timelock at which this output can be spent given the height at which
391 // this output was confirmed. We use `output_conf_height + 1` as a safe default as we can
392 // be confirmed in the next block and transactions with time lock `current_height + 1`
394 let absolute_timelock = match self {
395 PackageSolvingData::RevokedOutput(_) => output_conf_height + 1,
396 PackageSolvingData::RevokedHTLCOutput(_) => output_conf_height + 1,
397 PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => output_conf_height + 1,
398 PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => std::cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
399 PackageSolvingData::HolderHTLCOutput(ref outp) => std::cmp::max(outp.cltv_expiry, output_conf_height + 1),
400 PackageSolvingData::HolderFundingOutput(_) => output_conf_height + 1,
406 impl_writeable_tlv_based_enum!(PackageSolvingData, ;
408 (1, RevokedHTLCOutput),
409 (2, CounterpartyOfferedHTLCOutput),
410 (3, CounterpartyReceivedHTLCOutput),
411 (4, HolderHTLCOutput),
412 (5, HolderFundingOutput),
415 /// A malleable package might be aggregated with other packages to save on fees.
416 /// A untractable package has been counter-signed and aggregable will break cached counterparty
418 #[derive(Clone, PartialEq)]
419 pub(crate) enum PackageMalleability {
424 /// A structure to describe a package content that is generated by ChannelMonitor and
425 /// used by OnchainTxHandler to generate and broadcast transactions settling onchain claims.
427 /// A package is defined as one or more transactions claiming onchain outputs in reaction
428 /// to confirmation of a channel transaction. Those packages might be aggregated to save on
429 /// fees, if satisfaction of outputs's witnessScript let's us do so.
431 /// As packages are time-sensitive, we fee-bump and rebroadcast them at scheduled intervals.
432 /// Failing to confirm a package translate as a loss of funds for the user.
433 #[derive(Clone, PartialEq)]
434 pub struct PackageTemplate {
435 // List of onchain outputs and solving data to generate satisfying witnesses.
436 inputs: Vec<(BitcoinOutPoint, PackageSolvingData)>,
437 // Packages are deemed as malleable if we have local knwoledge of at least one set of
438 // private keys yielding a satisfying witnesses. Malleability implies that we can aggregate
439 // packages among them to save on fees or rely on RBF to bump their feerates.
440 // Untractable packages have been counter-signed and thus imply that we can't aggregate
441 // them without breaking signatures. Fee-bumping strategy will also rely on CPFP.
442 malleability: PackageMalleability,
443 // Block height after which the earlier-output belonging to this package is mature for a
444 // competing claim by the counterparty. As our chain tip becomes nearer from the timelock,
445 // the fee-bumping frequency will increase. See `OnchainTxHandler::get_height_timer`.
446 soonest_conf_deadline: u32,
447 // Determines if this package can be aggregated.
448 // Timelocked outputs belonging to the same transaction might have differing
449 // satisfying heights. Picking up the later height among the output set would be a valid
450 // aggregable strategy but it comes with at least 2 trade-offs :
451 // * earlier-output fund are going to take longer to come back
452 // * CLTV delta backing up a corresponding HTLC on an upstream channel could be swallowed
453 // by the requirement of the later-output part of the set
454 // For now, we mark such timelocked outputs as non-aggregable, though we might introduce
455 // smarter aggregable strategy in the future.
457 // Cache of package feerate committed at previous (re)broadcast. If bumping resources
458 // (either claimed output value or external utxo), it will keep increasing until holder
459 // or counterparty successful claim.
460 feerate_previous: u64,
461 // Cache of next height at which fee-bumping and rebroadcast will be attempted. In
462 // the future, we might abstract it to an observed mempool fluctuation.
463 height_timer: Option<u32>,
464 // Confirmation height of the claimed outputs set transaction. In case of reorg reaching
465 // it, we wipe out and forget the package.
466 height_original: u32,
469 impl PackageTemplate {
470 pub(crate) fn is_malleable(&self) -> bool {
471 self.malleability == PackageMalleability::Malleable
473 pub(crate) fn timelock(&self) -> u32 {
474 self.soonest_conf_deadline
476 pub(crate) fn aggregable(&self) -> bool {
479 pub(crate) fn set_feerate(&mut self, new_feerate: u64) {
480 self.feerate_previous = new_feerate;
482 pub(crate) fn timer(&self) -> Option<u32> {
483 if let Some(ref timer) = self.height_timer {
488 pub(crate) fn set_timer(&mut self, new_timer: Option<u32>) {
489 self.height_timer = new_timer;
491 pub(crate) fn outpoints(&self) -> Vec<&BitcoinOutPoint> {
492 self.inputs.iter().map(|(o, _)| o).collect()
494 pub(crate) fn split_package(&mut self, split_outp: &BitcoinOutPoint) -> Option<PackageTemplate> {
495 match self.malleability {
496 PackageMalleability::Malleable => {
497 let mut split_package = None;
498 let timelock = self.soonest_conf_deadline;
499 let aggregable = self.aggregable;
500 let feerate_previous = self.feerate_previous;
501 let height_timer = self.height_timer;
502 let height_original = self.height_original;
503 self.inputs.retain(|outp| {
504 if *split_outp == outp.0 {
505 split_package = Some(PackageTemplate {
506 inputs: vec![(outp.0, outp.1.clone())],
507 malleability: PackageMalleability::Malleable,
508 soonest_conf_deadline: timelock,
518 return split_package;
521 // Note, we may try to split on remote transaction for
522 // which we don't have a competing one (HTLC-Success before
523 // timelock expiration). This explain we don't panic!
524 // We should refactor OnchainTxHandler::block_connected to
525 // only test equality on competing claims.
530 pub(crate) fn merge_package(&mut self, mut merge_from: PackageTemplate) {
531 assert_eq!(self.height_original, merge_from.height_original);
532 if self.malleability == PackageMalleability::Untractable || merge_from.malleability == PackageMalleability::Untractable {
533 panic!("Merging template on untractable packages");
535 if !self.aggregable || !merge_from.aggregable {
536 panic!("Merging non aggregatable packages");
538 if let Some((_, lead_input)) = self.inputs.first() {
539 for (_, v) in merge_from.inputs.iter() {
540 if !lead_input.is_compatible(v) { panic!("Merging outputs from differing types !"); }
542 } else { panic!("Merging template on an empty package"); }
543 for (k, v) in merge_from.inputs.drain(..) {
544 self.inputs.push((k, v));
546 //TODO: verify coverage and sanity?
547 if self.soonest_conf_deadline > merge_from.soonest_conf_deadline {
548 self.soonest_conf_deadline = merge_from.soonest_conf_deadline;
550 if self.feerate_previous > merge_from.feerate_previous {
551 self.feerate_previous = merge_from.feerate_previous;
553 self.height_timer = cmp::min(self.height_timer, merge_from.height_timer);
555 /// Gets the amount of all outptus being spent by this package, only valid for malleable
557 fn package_amount(&self) -> u64 {
559 for (_, outp) in self.inputs.iter() {
560 amounts += outp.amount();
564 pub(crate) fn package_timelock(&self) -> u32 {
565 self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(self.height_original))
566 .max().expect("There must always be at least one output to spend in a PackageTemplate")
568 pub(crate) fn package_weight(&self, destination_script: &Script) -> usize {
569 let mut inputs_weight = 0;
570 let mut witnesses_weight = 2; // count segwit flags
571 for (_, outp) in self.inputs.iter() {
572 // previous_out_point: 36 bytes ; var_int: 1 byte ; sequence: 4 bytes
573 inputs_weight += 41 * WITNESS_SCALE_FACTOR;
574 witnesses_weight += outp.weight();
576 // version: 4 bytes ; count_tx_in: 1 byte ; count_tx_out: 1 byte ; lock_time: 4 bytes
577 let transaction_weight = 10 * WITNESS_SCALE_FACTOR;
578 // value: 8 bytes ; var_int: 1 byte ; pk_script: `destination_script.len()`
579 let output_weight = (8 + 1 + destination_script.len()) * WITNESS_SCALE_FACTOR;
580 inputs_weight + witnesses_weight + transaction_weight + output_weight
582 pub(crate) fn finalize_package<L: Deref, Signer: Sign>(&self, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64, destination_script: Script, logger: &L) -> Option<Transaction>
583 where L::Target: Logger,
585 match self.malleability {
586 PackageMalleability::Malleable => {
587 let mut bumped_tx = Transaction {
592 script_pubkey: destination_script,
596 for (outpoint, _) in self.inputs.iter() {
597 bumped_tx.input.push(TxIn {
598 previous_output: *outpoint,
599 script_sig: Script::new(),
600 sequence: 0xfffffffd,
604 for (i, (outpoint, out)) in self.inputs.iter().enumerate() {
605 log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
606 if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { return None; }
608 log_debug!(logger, "Finalized transaction {} ready to broadcast", bumped_tx.txid());
609 return Some(bumped_tx);
611 PackageMalleability::Untractable => {
612 debug_assert_eq!(value, 0, "value is ignored for non-malleable packages, should be zero to ensure callsites are correct");
613 if let Some((outpoint, outp)) = self.inputs.first() {
614 if let Some(final_tx) = outp.get_finalized_tx(outpoint, onchain_handler) {
615 log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
616 log_debug!(logger, "Finalized transaction {} ready to broadcast", final_tx.txid());
617 return Some(final_tx);
620 } else { panic!("API Error: Package must not be inputs empty"); }
624 /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
625 /// 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
626 /// height that once reached we should generate a new bumped "version" of the claim tx to be sure that we safely claim outputs before
627 /// that our counterparty can do so. If timelock expires soon, height timer is going to be scaled down in consequence to increase
628 /// frequency of the bump and so increase our bets of success.
629 pub(crate) fn get_height_timer(&self, current_height: u32) -> u32 {
630 if self.soonest_conf_deadline <= current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL {
631 return current_height + HIGH_FREQUENCY_BUMP_INTERVAL
632 } else if self.soonest_conf_deadline - current_height <= LOW_FREQUENCY_BUMP_INTERVAL {
633 return current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL
635 current_height + LOW_FREQUENCY_BUMP_INTERVAL
637 /// Returns value in satoshis to be included as package outgoing output amount and feerate with which package finalization should be done.
638 pub(crate) fn compute_package_output<F: Deref, L: Deref>(&self, predicted_weight: usize, fee_estimator: &F, logger: &L) -> Option<(u64, u64)>
639 where F::Target: FeeEstimator,
642 debug_assert!(self.malleability == PackageMalleability::Malleable, "The package output is fixed for non-malleable packages");
643 let input_amounts = self.package_amount();
644 // If old feerate is 0, first iteration of this claim, use normal fee calculation
645 if self.feerate_previous != 0 {
646 if let Some((new_fee, feerate)) = feerate_bump(predicted_weight, input_amounts, self.feerate_previous, fee_estimator, logger) {
647 // If new computed fee is superior at the whole claimable amount burn all in fees
648 if new_fee > input_amounts {
649 return Some((0, feerate));
651 return Some((input_amounts - new_fee, feerate));
655 if let Some((new_fee, feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
656 return Some((input_amounts - new_fee, feerate));
661 pub (crate) fn build_package(txid: Txid, vout: u32, input_solving_data: PackageSolvingData, soonest_conf_deadline: u32, aggregable: bool, height_original: u32) -> Self {
662 let malleability = match input_solving_data {
663 PackageSolvingData::RevokedOutput(..) => { PackageMalleability::Malleable },
664 PackageSolvingData::RevokedHTLCOutput(..) => { PackageMalleability::Malleable },
665 PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { PackageMalleability::Malleable },
666 PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { PackageMalleability::Malleable },
667 PackageSolvingData::HolderHTLCOutput(..) => { PackageMalleability::Untractable },
668 PackageSolvingData::HolderFundingOutput(..) => { PackageMalleability::Untractable },
670 let mut inputs = Vec::with_capacity(1);
671 inputs.push((BitcoinOutPoint { txid, vout }, input_solving_data));
675 soonest_conf_deadline,
684 impl Writeable for PackageTemplate {
685 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
686 writer.write_all(&byte_utils::be64_to_array(self.inputs.len() as u64))?;
687 for (ref outpoint, ref rev_outp) in self.inputs.iter() {
688 outpoint.write(writer)?;
689 rev_outp.write(writer)?;
691 write_tlv_fields!(writer, {
692 (0, self.soonest_conf_deadline, required),
693 (2, self.feerate_previous, required),
694 (4, self.height_original, required),
695 (6, self.height_timer, option)
701 impl Readable for PackageTemplate {
702 fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
703 let inputs_count = <u64 as Readable>::read(reader)?;
704 let mut inputs: Vec<(BitcoinOutPoint, PackageSolvingData)> = Vec::with_capacity(cmp::min(inputs_count as usize, MAX_ALLOC_SIZE / 128));
705 for _ in 0..inputs_count {
706 let outpoint = Readable::read(reader)?;
707 let rev_outp = Readable::read(reader)?;
708 inputs.push((outpoint, rev_outp));
710 let (malleability, aggregable) = if let Some((_, lead_input)) = inputs.first() {
712 PackageSolvingData::RevokedOutput(..) => { (PackageMalleability::Malleable, true) },
713 PackageSolvingData::RevokedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
714 PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
715 PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { (PackageMalleability::Malleable, false) },
716 PackageSolvingData::HolderHTLCOutput(..) => { (PackageMalleability::Untractable, false) },
717 PackageSolvingData::HolderFundingOutput(..) => { (PackageMalleability::Untractable, false) },
719 } else { return Err(DecodeError::InvalidValue); };
720 let mut soonest_conf_deadline = 0;
721 let mut feerate_previous = 0;
722 let mut height_timer = None;
723 let mut height_original = 0;
724 read_tlv_fields!(reader, {
725 (0, soonest_conf_deadline, required),
726 (2, feerate_previous, required),
727 (4, height_original, required),
728 (6, height_timer, option),
733 soonest_conf_deadline,
742 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
743 /// weight. We start with the highest priority feerate returned by the node's fee estimator then
744 /// fall-back to lower priorities until we have enough value available to suck from.
746 /// If the proposed fee is less than the available spent output's values, we return the proposed
747 /// fee and the corresponding updated feerate. If the proposed fee is equal or more than the
748 /// available spent output's values, we return nothing
749 fn compute_fee_from_spent_amounts<F: Deref, L: Deref>(input_amounts: u64, predicted_weight: usize, fee_estimator: &F, logger: &L) -> Option<(u64, u64)>
750 where F::Target: FeeEstimator,
753 let mut updated_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64;
754 let mut fee = updated_feerate * (predicted_weight as u64) / 1000;
755 if input_amounts <= fee {
756 updated_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal) as u64;
757 fee = updated_feerate * (predicted_weight as u64) / 1000;
758 if input_amounts <= fee {
759 updated_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background) as u64;
760 fee = updated_feerate * (predicted_weight as u64) / 1000;
761 if input_amounts <= fee {
762 log_error!(logger, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
766 log_warn!(logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
768 Some((fee, updated_feerate))
771 log_warn!(logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
773 Some((fee, updated_feerate))
776 Some((fee, updated_feerate))
780 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
781 /// weight. If feerates proposed by the fee-estimator have been increasing since last fee-bumping
782 /// attempt, use them. Otherwise, blindly bump the feerate by 25% of the previous feerate. We also
783 /// verify that those bumping heuristics respect BIP125 rules 3) and 4) and if required adjust
784 /// the new fee to meet the RBF policy requirement.
785 fn feerate_bump<F: Deref, L: Deref>(predicted_weight: usize, input_amounts: u64, previous_feerate: u64, fee_estimator: &F, logger: &L) -> Option<(u64, u64)>
786 where F::Target: FeeEstimator,
789 // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
790 let new_fee = if let Some((new_fee, _)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
791 let updated_feerate = new_fee / (predicted_weight as u64 * 1000);
792 if updated_feerate > previous_feerate {
795 // ...else just increase the previous feerate by 25% (because that's a nice number)
796 let new_fee = previous_feerate * (predicted_weight as u64) / 750;
797 if input_amounts <= new_fee {
798 log_warn!(logger, "Can't 25% bump new claiming tx, amount {} is too small", input_amounts);
804 log_warn!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", input_amounts);
808 let previous_fee = previous_feerate * (predicted_weight as u64) / 1000;
809 let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * (predicted_weight as u64) / 1000;
810 // BIP 125 Opt-in Full Replace-by-Fee Signaling
811 // * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
812 // * 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.
813 let new_fee = if new_fee < previous_fee + min_relay_fee {
814 new_fee + previous_fee + min_relay_fee - new_fee
818 Some((new_fee, new_fee * 1000 / (predicted_weight as u64)))
823 use chain::package::{CounterpartyReceivedHTLCOutput, HolderHTLCOutput, PackageTemplate, PackageSolvingData, RevokedOutput, WEIGHT_REVOKED_OUTPUT};
825 use ln::chan_utils::HTLCOutputInCommitment;
826 use ln::{PaymentPreimage, PaymentHash};
828 use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
829 use bitcoin::blockdata::script::Script;
830 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
832 use bitcoin::hashes::hex::FromHex;
834 use bitcoin::secp256k1::key::{PublicKey,SecretKey};
835 use bitcoin::secp256k1::Secp256k1;
837 macro_rules! dumb_revk_output {
838 ($secp_ctx: expr) => {
840 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
841 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
842 PackageSolvingData::RevokedOutput(RevokedOutput::build(dumb_point, dumb_point, dumb_point, dumb_scalar, 0, 0))
847 macro_rules! dumb_counterparty_output {
848 ($secp_ctx: expr, $amt: expr) => {
850 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
851 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
852 let hash = PaymentHash([1; 32]);
853 let htlc = HTLCOutputInCommitment { offered: true, amount_msat: $amt, cltv_expiry: 0, payment_hash: hash, transaction_output_index: None };
854 PackageSolvingData::CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput::build(dumb_point, dumb_point, dumb_point, htlc))
859 macro_rules! dumb_htlc_output {
862 let preimage = PaymentPreimage([2;32]);
863 PackageSolvingData::HolderHTLCOutput(HolderHTLCOutput::build_accepted(preimage, 0))
870 fn test_package_differing_heights() {
871 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
872 let secp_ctx = Secp256k1::new();
873 let revk_outp = dumb_revk_output!(secp_ctx);
875 let mut package_one_hundred = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
876 let package_two_hundred = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 200);
877 package_one_hundred.merge_package(package_two_hundred);
882 fn test_package_untractable_merge_to() {
883 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
884 let secp_ctx = Secp256k1::new();
885 let revk_outp = dumb_revk_output!(secp_ctx);
886 let htlc_outp = dumb_htlc_output!();
888 let mut untractable_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
889 let malleable_package = PackageTemplate::build_package(txid, 1, htlc_outp.clone(), 1000, true, 100);
890 untractable_package.merge_package(malleable_package);
895 fn test_package_untractable_merge_from() {
896 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
897 let secp_ctx = Secp256k1::new();
898 let htlc_outp = dumb_htlc_output!();
899 let revk_outp = dumb_revk_output!(secp_ctx);
901 let mut malleable_package = PackageTemplate::build_package(txid, 0, htlc_outp.clone(), 1000, true, 100);
902 let untractable_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
903 malleable_package.merge_package(untractable_package);
908 fn test_package_noaggregation_to() {
909 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
910 let secp_ctx = Secp256k1::new();
911 let revk_outp = dumb_revk_output!(secp_ctx);
913 let mut noaggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, false, 100);
914 let aggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
915 noaggregation_package.merge_package(aggregation_package);
920 fn test_package_noaggregation_from() {
921 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
922 let secp_ctx = Secp256k1::new();
923 let revk_outp = dumb_revk_output!(secp_ctx);
925 let mut aggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
926 let noaggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, false, 100);
927 aggregation_package.merge_package(noaggregation_package);
932 fn test_package_empty() {
933 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
934 let secp_ctx = Secp256k1::new();
935 let revk_outp = dumb_revk_output!(secp_ctx);
937 let mut empty_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
938 empty_package.inputs = vec![];
939 let package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
940 empty_package.merge_package(package);
945 fn test_package_differing_categories() {
946 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
947 let secp_ctx = Secp256k1::new();
948 let revk_outp = dumb_revk_output!(secp_ctx);
949 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 0);
951 let mut revoked_package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
952 let counterparty_package = PackageTemplate::build_package(txid, 1, counterparty_outp, 1000, true, 100);
953 revoked_package.merge_package(counterparty_package);
957 fn test_package_split_malleable() {
958 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
959 let secp_ctx = Secp256k1::new();
960 let revk_outp_one = dumb_revk_output!(secp_ctx);
961 let revk_outp_two = dumb_revk_output!(secp_ctx);
962 let revk_outp_three = dumb_revk_output!(secp_ctx);
964 let mut package_one = PackageTemplate::build_package(txid, 0, revk_outp_one, 1000, true, 100);
965 let package_two = PackageTemplate::build_package(txid, 1, revk_outp_two, 1000, true, 100);
966 let package_three = PackageTemplate::build_package(txid, 2, revk_outp_three, 1000, true, 100);
968 package_one.merge_package(package_two);
969 package_one.merge_package(package_three);
970 assert_eq!(package_one.outpoints().len(), 3);
972 if let Some(split_package) = package_one.split_package(&BitcoinOutPoint { txid, vout: 1 }) {
973 // Packages attributes should be identical
974 assert!(split_package.is_malleable());
975 assert_eq!(split_package.soonest_conf_deadline, package_one.soonest_conf_deadline);
976 assert_eq!(split_package.aggregable, package_one.aggregable);
977 assert_eq!(split_package.feerate_previous, package_one.feerate_previous);
978 assert_eq!(split_package.height_timer, package_one.height_timer);
979 assert_eq!(split_package.height_original, package_one.height_original);
981 assert_eq!(package_one.outpoints().len(), 2);
985 fn test_package_split_untractable() {
986 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
987 let htlc_outp_one = dumb_htlc_output!();
989 let mut package_one = PackageTemplate::build_package(txid, 0, htlc_outp_one, 1000, true, 100);
990 let ret_split = package_one.split_package(&BitcoinOutPoint { txid, vout: 0});
991 assert!(ret_split.is_none());
995 fn test_package_timer() {
996 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
997 let secp_ctx = Secp256k1::new();
998 let revk_outp = dumb_revk_output!(secp_ctx);
1000 let mut package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1001 let timer_none = package.timer();
1002 assert!(timer_none.is_none());
1003 package.set_timer(Some(100));
1004 if let Some(timer_some) = package.timer() {
1005 assert_eq!(timer_some, 100);
1010 fn test_package_amounts() {
1011 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1012 let secp_ctx = Secp256k1::new();
1013 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000);
1015 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1016 assert_eq!(package.package_amount(), 1000);
1020 fn test_package_weight() {
1021 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1022 let secp_ctx = Secp256k1::new();
1023 let revk_outp = dumb_revk_output!(secp_ctx);
1025 let package = PackageTemplate::build_package(txid, 0, revk_outp, 0, true, 100);
1026 // (nVersion (4) + nLocktime (4) + count_tx_in (1) + prevout (36) + sequence (4) + script_length (1) + count_tx_out (1) + value (8) + var_int (1)) * WITNESS_SCALE_FACTOR
1027 // + witness marker (2) + WEIGHT_REVOKED_OUTPUT
1028 assert_eq!(package.package_weight(&Script::new()), (4 + 4 + 1 + 36 + 4 + 1 + 1 + 8 + 1) * WITNESS_SCALE_FACTOR + 2 + WEIGHT_REVOKED_OUTPUT as usize);