_ Git - rust-lightning/blob - lightning/src/chain/package.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! 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.
  13
  14 use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
  15 use bitcoin::blockdata::transaction::{TxOut,TxIn, Transaction, EcdsaSighashType};
  16 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
  17 use bitcoin::blockdata::script::Script;
  18
  19 use bitcoin::hash_types::Txid;
  20
  21 use bitcoin::secp256k1::{SecretKey,PublicKey};
  22
  23 use crate::ln::PaymentPreimage;
  24 use crate::ln::chan_utils::{TxCreationKeys, HTLCOutputInCommitment};
  25 use crate::ln::chan_utils;
  26 use crate::ln::msgs::DecodeError;
  27 use crate::chain::chaininterface::{FeeEstimator, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
  28 use crate::chain::keysinterface::Sign;
  29 use crate::chain::onchaintx::OnchainTxHandler;
  30 use crate::util::logger::Logger;
  31 use crate::util::ser::{Readable, Writer, Writeable};
  32
  33 use crate::io;
  34 use crate::prelude::*;
  35 use core::cmp;
  36 #[cfg(anchors)]
  37 use core::convert::TryInto;
  38 use core::mem;
  39 use core::ops::Deref;
  40 use bitcoin::{PackedLockTime, Sequence, Witness};
  41
  42 use super::chaininterface::LowerBoundedFeeEstimator;
  43
  44 const MAX_ALLOC_SIZE: usize = 64*1024;
  45
  46
  47 pub(crate) fn weight_revoked_offered_htlc(opt_anchors: bool) -> u64 {
  48         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  49         const WEIGHT_REVOKED_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 + 133;
  50         const WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  51         if opt_anchors { WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS } else { WEIGHT_REVOKED_OFFERED_HTLC }
  52 }
  53
  54 pub(crate) fn weight_revoked_received_htlc(opt_anchors: bool) -> u64 {
  55         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  56         const WEIGHT_REVOKED_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 +  139;
  57         const WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  58         if opt_anchors { WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS } else { WEIGHT_REVOKED_RECEIVED_HTLC }
  59 }
  60
  61 pub(crate) fn weight_offered_htlc(opt_anchors: bool) -> u64 {
  62         // number_of_witness_elements + sig_length + counterpartyhtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
  63         const WEIGHT_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 32 + 1 + 133;
  64         const WEIGHT_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  65         if opt_anchors { WEIGHT_OFFERED_HTLC_ANCHORS } else { WEIGHT_OFFERED_HTLC }
  66 }
  67
  68 pub(crate) fn weight_received_htlc(opt_anchors: bool) -> u64 {
  69         // number_of_witness_elements + sig_length + counterpartyhtlc_sig + empty_vec_length + empty_vec + witness_script_length + witness_script
  70         const WEIGHT_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 139;
  71         const WEIGHT_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  72         if opt_anchors { WEIGHT_RECEIVED_HTLC_ANCHORS } else { WEIGHT_RECEIVED_HTLC }
  73 }
  74
  75 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
  76 pub(crate) const WEIGHT_REVOKED_OUTPUT: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 77;
  77
  78 /// Height delay at which transactions are fee-bumped/rebroadcasted with a low priority.
  79 const LOW_FREQUENCY_BUMP_INTERVAL: u32 = 15;
  80 /// Height delay at which transactions are fee-bumped/rebroadcasted with a middle priority.
  81 const MIDDLE_FREQUENCY_BUMP_INTERVAL: u32 = 3;
  82 /// Height delay at which transactions are fee-bumped/rebroadcasted with a high priority.
  83 const HIGH_FREQUENCY_BUMP_INTERVAL: u32 = 1;
  84
  85 /// A struct to describe a revoked output and corresponding information to generate a solving
  86 /// witness spending a commitment `to_local` output or a second-stage HTLC transaction output.
  87 ///
  88 /// CSV and pubkeys are used as part of a witnessScript redeeming a balance output, amount is used
  89 /// as part of the signature hash and revocation secret to generate a satisfying witness.
  90 #[derive(Clone, PartialEq, Eq)]
  91 pub(crate) struct RevokedOutput {
  92         per_commitment_point: PublicKey,
  93         counterparty_delayed_payment_base_key: PublicKey,
  94         counterparty_htlc_base_key: PublicKey,
  95         per_commitment_key: SecretKey,
  96         weight: u64,
  97         amount: u64,
  98         on_counterparty_tx_csv: u16,
  99 }
 100
 101 impl RevokedOutput {
 102         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 {
 103                 RevokedOutput {
 104                         per_commitment_point,
 105                         counterparty_delayed_payment_base_key,
 106                         counterparty_htlc_base_key,
 107                         per_commitment_key,
 108                         weight: WEIGHT_REVOKED_OUTPUT,
 109                         amount,
 110                         on_counterparty_tx_csv
 111                 }
 112         }
 113 }
 114
 115 impl_writeable_tlv_based!(RevokedOutput, {
 116         (0, per_commitment_point, required),
 117         (2, counterparty_delayed_payment_base_key, required),
 118         (4, counterparty_htlc_base_key, required),
 119         (6, per_commitment_key, required),
 120         (8, weight, required),
 121         (10, amount, required),
 122         (12, on_counterparty_tx_csv, required),
 123 });
 124
 125 /// A struct to describe a revoked offered output and corresponding information to generate a
 126 /// solving witness.
 127 ///
 128 /// HTLCOuputInCommitment (hash timelock, direction) and pubkeys are used to generate a suitable
 129 /// witnessScript.
 130 ///
 131 /// CSV is used as part of a witnessScript redeeming a balance output, amount is used as part
 132 /// of the signature hash and revocation secret to generate a satisfying witness.
 133 #[derive(Clone, PartialEq, Eq)]
 134 pub(crate) struct RevokedHTLCOutput {
 135         per_commitment_point: PublicKey,
 136         counterparty_delayed_payment_base_key: PublicKey,
 137         counterparty_htlc_base_key: PublicKey,
 138         per_commitment_key: SecretKey,
 139         weight: u64,
 140         amount: u64,
 141         htlc: HTLCOutputInCommitment,
 142 }
 143
 144 impl RevokedHTLCOutput {
 145         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, opt_anchors: bool) -> Self {
 146                 let weight = if htlc.offered { weight_revoked_offered_htlc(opt_anchors) } else { weight_revoked_received_htlc(opt_anchors) };
 147                 RevokedHTLCOutput {
 148                         per_commitment_point,
 149                         counterparty_delayed_payment_base_key,
 150                         counterparty_htlc_base_key,
 151                         per_commitment_key,
 152                         weight,
 153                         amount,
 154                         htlc
 155                 }
 156         }
 157 }
 158
 159 impl_writeable_tlv_based!(RevokedHTLCOutput, {
 160         (0, per_commitment_point, required),
 161         (2, counterparty_delayed_payment_base_key, required),
 162         (4, counterparty_htlc_base_key, required),
 163         (6, per_commitment_key, required),
 164         (8, weight, required),
 165         (10, amount, required),
 166         (12, htlc, required),
 167 });
 168
 169 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 170 ///
 171 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 172 /// witnessScript.
 173 ///
 174 /// The preimage is used as part of the witness.
 175 #[derive(Clone, PartialEq, Eq)]
 176 pub(crate) struct CounterpartyOfferedHTLCOutput {
 177         per_commitment_point: PublicKey,
 178         counterparty_delayed_payment_base_key: PublicKey,
 179         counterparty_htlc_base_key: PublicKey,
 180         preimage: PaymentPreimage,
 181         htlc: HTLCOutputInCommitment,
 182         opt_anchors: Option<()>,
 183 }
 184
 185 impl CounterpartyOfferedHTLCOutput {
 186         pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, preimage: PaymentPreimage, htlc: HTLCOutputInCommitment, opt_anchors: bool) -> Self {
 187                 CounterpartyOfferedHTLCOutput {
 188                         per_commitment_point,
 189                         counterparty_delayed_payment_base_key,
 190                         counterparty_htlc_base_key,
 191                         preimage,
 192                         htlc,
 193                         opt_anchors: if opt_anchors { Some(()) } else { None },
 194                 }
 195         }
 196
 197         fn opt_anchors(&self) -> bool {
 198                 self.opt_anchors.is_some()
 199         }
 200 }
 201
 202 impl_writeable_tlv_based!(CounterpartyOfferedHTLCOutput, {
 203         (0, per_commitment_point, required),
 204         (1, opt_anchors, option),
 205         (2, counterparty_delayed_payment_base_key, required),
 206         (4, counterparty_htlc_base_key, required),
 207         (6, preimage, required),
 208         (8, htlc, required),
 209 });
 210
 211 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 212 ///
 213 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 214 /// witnessScript.
 215 #[derive(Clone, PartialEq, Eq)]
 216 pub(crate) struct CounterpartyReceivedHTLCOutput {
 217         per_commitment_point: PublicKey,
 218         counterparty_delayed_payment_base_key: PublicKey,
 219         counterparty_htlc_base_key: PublicKey,
 220         htlc: HTLCOutputInCommitment,
 221         opt_anchors: Option<()>,
 222 }
 223
 224 impl CounterpartyReceivedHTLCOutput {
 225         pub(crate) fn build(per_commitment_point: PublicKey, counterparty_delayed_payment_base_key: PublicKey, counterparty_htlc_base_key: PublicKey, htlc: HTLCOutputInCommitment, opt_anchors: bool) -> Self {
 226                 CounterpartyReceivedHTLCOutput {
 227                         per_commitment_point,
 228                         counterparty_delayed_payment_base_key,
 229                         counterparty_htlc_base_key,
 230                         htlc,
 231                         opt_anchors: if opt_anchors { Some(()) } else { None },
 232                 }
 233         }
 234
 235         fn opt_anchors(&self) -> bool {
 236                 self.opt_anchors.is_some()
 237         }
 238 }
 239
 240 impl_writeable_tlv_based!(CounterpartyReceivedHTLCOutput, {
 241         (0, per_commitment_point, required),
 242         (1, opt_anchors, option),
 243         (2, counterparty_delayed_payment_base_key, required),
 244         (4, counterparty_htlc_base_key, required),
 245         (6, htlc, required),
 246 });
 247
 248 /// A struct to describe a HTLC output on holder commitment transaction.
 249 ///
 250 /// Either offered or received, the amount is always used as part of the bip143 sighash.
 251 /// Preimage is only included as part of the witness in former case.
 252 #[derive(Clone, PartialEq, Eq)]
 253 pub(crate) struct HolderHTLCOutput {
 254         preimage: Option<PaymentPreimage>,
 255         amount_msat: u64,
 256         /// Defaults to 0 for HTLC-Success transactions, which have no expiry
 257         cltv_expiry: u32,
 258         opt_anchors: Option<()>,
 259 }
 260
 261 impl HolderHTLCOutput {
 262         pub(crate) fn build_offered(amount_msat: u64, cltv_expiry: u32, opt_anchors: bool) -> Self {
 263                 HolderHTLCOutput {
 264                         preimage: None,
 265                         amount_msat,
 266                         cltv_expiry,
 267                         opt_anchors: if opt_anchors { Some(()) } else { None } ,
 268                 }
 269         }
 270
 271         pub(crate) fn build_accepted(preimage: PaymentPreimage, amount_msat: u64, opt_anchors: bool) -> Self {
 272                 HolderHTLCOutput {
 273                         preimage: Some(preimage),
 274                         amount_msat,
 275                         cltv_expiry: 0,
 276                         opt_anchors: if opt_anchors { Some(()) } else { None } ,
 277                 }
 278         }
 279
 280         fn opt_anchors(&self) -> bool {
 281                 self.opt_anchors.is_some()
 282         }
 283 }
 284
 285 impl_writeable_tlv_based!(HolderHTLCOutput, {
 286         (0, amount_msat, required),
 287         (2, cltv_expiry, required),
 288         (4, preimage, option),
 289         (6, opt_anchors, option)
 290 });
 291
 292 /// A struct to describe the channel output on the funding transaction.
 293 ///
 294 /// witnessScript is used as part of the witness redeeming the funding utxo.
 295 #[derive(Clone, PartialEq, Eq)]
 296 pub(crate) struct HolderFundingOutput {
 297         funding_redeemscript: Script,
 298         funding_amount: Option<u64>,
 299         opt_anchors: Option<()>,
 300 }
 301
 302
 303 impl HolderFundingOutput {
 304         pub(crate) fn build(funding_redeemscript: Script, funding_amount: u64, opt_anchors: bool) -> Self {
 305                 HolderFundingOutput {
 306                         funding_redeemscript,
 307                         funding_amount: Some(funding_amount),
 308                         opt_anchors: if opt_anchors { Some(()) } else { None },
 309                 }
 310         }
 311
 312         fn opt_anchors(&self) -> bool {
 313                 self.opt_anchors.is_some()
 314         }
 315 }
 316
 317 impl_writeable_tlv_based!(HolderFundingOutput, {
 318         (0, funding_redeemscript, required),
 319         (1, opt_anchors, option),
 320         (3, funding_amount, option),
 321 });
 322
 323 /// A wrapper encapsulating all in-protocol differing outputs types.
 324 ///
 325 /// The generic API offers access to an outputs common attributes or allow transformation such as
 326 /// finalizing an input claiming the output.
 327 #[derive(Clone, PartialEq, Eq)]
 328 pub(crate) enum PackageSolvingData {
 329         RevokedOutput(RevokedOutput),
 330         RevokedHTLCOutput(RevokedHTLCOutput),
 331         CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput),
 332         CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput),
 333         HolderHTLCOutput(HolderHTLCOutput),
 334         HolderFundingOutput(HolderFundingOutput),
 335 }
 336
 337 impl PackageSolvingData {
 338         fn amount(&self) -> u64 {
 339                 let amt = match self {
 340                         PackageSolvingData::RevokedOutput(ref outp) => outp.amount,
 341                         PackageSolvingData::RevokedHTLCOutput(ref outp) => outp.amount,
 342                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 343                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 344                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 345                                 debug_assert!(outp.opt_anchors());
 346                                 outp.amount_msat / 1000
 347                         },
 348                         PackageSolvingData::HolderFundingOutput(ref outp) => {
 349                                 debug_assert!(outp.opt_anchors());
 350                                 outp.funding_amount.unwrap()
 351                         }
 352                 };
 353                 amt
 354         }
 355         fn weight(&self) -> usize {
 356                 match self {
 357                         PackageSolvingData::RevokedOutput(ref outp) => outp.weight as usize,
 358                         PackageSolvingData::RevokedHTLCOutput(ref outp) => outp.weight as usize,
 359                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => weight_offered_htlc(outp.opt_anchors()) as usize,
 360                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => weight_received_htlc(outp.opt_anchors()) as usize,
 361                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 362                                 debug_assert!(outp.opt_anchors());
 363                                 if outp.preimage.is_none() {
 364                                         weight_offered_htlc(true) as usize
 365                                 } else {
 366                                         weight_received_htlc(true) as usize
 367                                 }
 368                         },
 369                         // Since HolderFundingOutput maps to an untractable package that is already signed, its
 370                         // weight can be determined from the transaction itself.
 371                         PackageSolvingData::HolderFundingOutput(..) => unreachable!(),
 372                 }
 373         }
 374         fn is_compatible(&self, input: &PackageSolvingData) -> bool {
 375                 match self {
 376                         PackageSolvingData::RevokedOutput(..) => {
 377                                 match input {
 378                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 379                                         PackageSolvingData::RevokedOutput(..) => { true },
 380                                         _ => { false }
 381                                 }
 382                         },
 383                         PackageSolvingData::RevokedHTLCOutput(..) => {
 384                                 match input {
 385                                         PackageSolvingData::RevokedOutput(..) => { true },
 386                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 387                                         _ => { false }
 388                                 }
 389                         },
 390                         _ => { mem::discriminant(self) == mem::discriminant(&input) }
 391                 }
 392         }
 393         fn finalize_input<Signer: Sign>(&self, bumped_tx: &mut Transaction, i: usize, onchain_handler: &mut OnchainTxHandler<Signer>) -> bool {
 394                 match self {
 395                         PackageSolvingData::RevokedOutput(ref outp) => {
 396                                 let 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);
 397                                 let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key);
 398                                 //TODO: should we panic on signer failure ?
 399                                 if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) {
 400                                         let mut ser_sig = sig.serialize_der().to_vec();
 401                                         ser_sig.push(EcdsaSighashType::All as u8);
 402                                         bumped_tx.input[i].witness.push(ser_sig);
 403                                         bumped_tx.input[i].witness.push(vec!(1));
 404                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 405                                 } else { return false; }
 406                         },
 407                         PackageSolvingData::RevokedHTLCOutput(ref outp) => {
 408                                 let 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);
 409                                 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
 410                                 //TODO: should we panic on signer failure ?
 411                                 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) {
 412                                         let mut ser_sig = sig.serialize_der().to_vec();
 413                                         ser_sig.push(EcdsaSighashType::All as u8);
 414                                         bumped_tx.input[i].witness.push(ser_sig);
 415                                         bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
 416                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 417                                 } else { return false; }
 418                         },
 419                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => {
 420                                 let 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);
 421                                 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
 422
 423                                 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) {
 424                                         let mut ser_sig = sig.serialize_der().to_vec();
 425                                         ser_sig.push(EcdsaSighashType::All as u8);
 426                                         bumped_tx.input[i].witness.push(ser_sig);
 427                                         bumped_tx.input[i].witness.push(outp.preimage.0.to_vec());
 428                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 429                                 }
 430                         },
 431                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => {
 432                                 let 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);
 433                                 let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&outp.htlc, onchain_handler.opt_anchors(), &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
 434
 435                                 bumped_tx.lock_time = PackedLockTime(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
 436                                 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) {
 437                                         let mut ser_sig = sig.serialize_der().to_vec();
 438                                         ser_sig.push(EcdsaSighashType::All as u8);
 439                                         bumped_tx.input[i].witness.push(ser_sig);
 440                                         // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
 441                                         bumped_tx.input[i].witness.push(vec![]);
 442                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 443                                 }
 444                         },
 445                         _ => { panic!("API Error!"); }
 446                 }
 447                 true
 448         }
 449         fn get_finalized_tx<Signer: Sign>(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler<Signer>) -> Option<Transaction> {
 450                 match self {
 451                         PackageSolvingData::HolderHTLCOutput(ref outp) => { return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage); }
 452                         PackageSolvingData::HolderFundingOutput(ref outp) => { return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript)); }
 453                         _ => { panic!("API Error!"); }
 454                 }
 455         }
 456         fn absolute_tx_timelock(&self, output_conf_height: u32) -> u32 {
 457                 // Get the absolute timelock at which this output can be spent given the height at which
 458                 // this output was confirmed. We use `output_conf_height + 1` as a safe default as we can
 459                 // be confirmed in the next block and transactions with time lock `current_height + 1`
 460                 // always propagate.
 461                 let absolute_timelock = match self {
 462                         PackageSolvingData::RevokedOutput(_) => output_conf_height + 1,
 463                         PackageSolvingData::RevokedHTLCOutput(_) => output_conf_height + 1,
 464                         PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => output_conf_height + 1,
 465                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
 466                         PackageSolvingData::HolderHTLCOutput(ref outp) => cmp::max(outp.cltv_expiry, output_conf_height + 1),
 467                         PackageSolvingData::HolderFundingOutput(_) => output_conf_height + 1,
 468                 };
 469                 absolute_timelock
 470         }
 471 }
 472
 473 impl_writeable_tlv_based_enum!(PackageSolvingData, ;
 474         (0, RevokedOutput),
 475         (1, RevokedHTLCOutput),
 476         (2, CounterpartyOfferedHTLCOutput),
 477         (3, CounterpartyReceivedHTLCOutput),
 478         (4, HolderHTLCOutput),
 479         (5, HolderFundingOutput),
 480 );
 481
 482 /// A malleable package might be aggregated with other packages to save on fees.
 483 /// A untractable package has been counter-signed and aggregable will break cached counterparty
 484 /// signatures.
 485 #[derive(Clone, PartialEq, Eq)]
 486 pub(crate) enum PackageMalleability {
 487         Malleable,
 488         Untractable,
 489 }
 490
 491 /// A structure to describe a package content that is generated by ChannelMonitor and
 492 /// used by OnchainTxHandler to generate and broadcast transactions settling onchain claims.
 493 ///
 494 /// A package is defined as one or more transactions claiming onchain outputs in reaction
 495 /// to confirmation of a channel transaction. Those packages might be aggregated to save on
 496 /// fees, if satisfaction of outputs's witnessScript let's us do so.
 497 ///
 498 /// As packages are time-sensitive, we fee-bump and rebroadcast them at scheduled intervals.
 499 /// Failing to confirm a package translate as a loss of funds for the user.
 500 #[derive(Clone, PartialEq, Eq)]
 501 pub struct PackageTemplate {
 502         // List of onchain outputs and solving data to generate satisfying witnesses.
 503         inputs: Vec<(BitcoinOutPoint, PackageSolvingData)>,
 504         // Packages are deemed as malleable if we have local knwoledge of at least one set of
 505         // private keys yielding a satisfying witnesses. Malleability implies that we can aggregate
 506         // packages among them to save on fees or rely on RBF to bump their feerates.
 507         // Untractable packages have been counter-signed and thus imply that we can't aggregate
 508         // them without breaking signatures. Fee-bumping strategy will also rely on CPFP.
 509         malleability: PackageMalleability,
 510         // Block height after which the earlier-output belonging to this package is mature for a
 511         // competing claim by the counterparty. As our chain tip becomes nearer from the timelock,
 512         // the fee-bumping frequency will increase. See `OnchainTxHandler::get_height_timer`.
 513         soonest_conf_deadline: u32,
 514         // Determines if this package can be aggregated.
 515         // Timelocked outputs belonging to the same transaction might have differing
 516         // satisfying heights. Picking up the later height among the output set would be a valid
 517         // aggregable strategy but it comes with at least 2 trade-offs :
 518         // * earlier-output fund are going to take longer to come back
 519         // * CLTV delta backing up a corresponding HTLC on an upstream channel could be swallowed
 520         // by the requirement of the later-output part of the set
 521         // For now, we mark such timelocked outputs as non-aggregable, though we might introduce
 522         // smarter aggregable strategy in the future.
 523         aggregable: bool,
 524         // Cache of package feerate committed at previous (re)broadcast. If bumping resources
 525         // (either claimed output value or external utxo), it will keep increasing until holder
 526         // or counterparty successful claim.
 527         feerate_previous: u64,
 528         // Cache of next height at which fee-bumping and rebroadcast will be attempted. In
 529         // the future, we might abstract it to an observed mempool fluctuation.
 530         height_timer: Option<u32>,
 531         // Confirmation height of the claimed outputs set transaction. In case of reorg reaching
 532         // it, we wipe out and forget the package.
 533         height_original: u32,
 534 }
 535
 536 impl PackageTemplate {
 537         pub(crate) fn is_malleable(&self) -> bool {
 538                 self.malleability == PackageMalleability::Malleable
 539         }
 540         pub(crate) fn timelock(&self) -> u32 {
 541                 self.soonest_conf_deadline
 542         }
 543         pub(crate) fn aggregable(&self) -> bool {
 544                 self.aggregable
 545         }
 546         pub(crate) fn set_feerate(&mut self, new_feerate: u64) {
 547                 self.feerate_previous = new_feerate;
 548         }
 549         pub(crate) fn timer(&self) -> Option<u32> {
 550                 if let Some(ref timer) = self.height_timer {
 551                         return Some(*timer);
 552                 }
 553                 None
 554         }
 555         pub(crate) fn set_timer(&mut self, new_timer: Option<u32>) {
 556                 self.height_timer = new_timer;
 557         }
 558         pub(crate) fn outpoints(&self) -> Vec<&BitcoinOutPoint> {
 559                 self.inputs.iter().map(|(o, _)| o).collect()
 560         }
 561         pub(crate) fn inputs(&self) -> impl ExactSizeIterator<Item = &PackageSolvingData> {
 562                 self.inputs.iter().map(|(_, i)| i)
 563         }
 564         pub(crate) fn split_package(&mut self, split_outp: &BitcoinOutPoint) -> Option<PackageTemplate> {
 565                 match self.malleability {
 566                         PackageMalleability::Malleable => {
 567                                 let mut split_package = None;
 568                                 let timelock = self.soonest_conf_deadline;
 569                                 let aggregable = self.aggregable;
 570                                 let feerate_previous = self.feerate_previous;
 571                                 let height_timer = self.height_timer;
 572                                 let height_original = self.height_original;
 573                                 self.inputs.retain(|outp| {
 574                                         if *split_outp == outp.0 {
 575                                                 split_package = Some(PackageTemplate {
 576                                                         inputs: vec![(outp.0, outp.1.clone())],
 577                                                         malleability: PackageMalleability::Malleable,
 578                                                         soonest_conf_deadline: timelock,
 579                                                         aggregable,
 580                                                         feerate_previous,
 581                                                         height_timer,
 582                                                         height_original,
 583                                                 });
 584                                                 return false;
 585                                         }
 586                                         return true;
 587                                 });
 588                                 return split_package;
 589                         },
 590                         _ => {
 591                                 // Note, we may try to split on remote transaction for
 592                                 // which we don't have a competing one (HTLC-Success before
 593                                 // timelock expiration). This explain we don't panic!
 594                                 // We should refactor OnchainTxHandler::block_connected to
 595                                 // only test equality on competing claims.
 596                                 return None;
 597                         }
 598                 }
 599         }
 600         pub(crate) fn merge_package(&mut self, mut merge_from: PackageTemplate) {
 601                 assert_eq!(self.height_original, merge_from.height_original);
 602                 if self.malleability == PackageMalleability::Untractable || merge_from.malleability == PackageMalleability::Untractable {
 603                         panic!("Merging template on untractable packages");
 604                 }
 605                 if !self.aggregable || !merge_from.aggregable {
 606                         panic!("Merging non aggregatable packages");
 607                 }
 608                 if let Some((_, lead_input)) = self.inputs.first() {
 609                         for (_, v) in merge_from.inputs.iter() {
 610                                 if !lead_input.is_compatible(v) { panic!("Merging outputs from differing types !"); }
 611                         }
 612                 } else { panic!("Merging template on an empty package"); }
 613                 for (k, v) in merge_from.inputs.drain(..) {
 614                         self.inputs.push((k, v));
 615                 }
 616                 //TODO: verify coverage and sanity?
 617                 if self.soonest_conf_deadline > merge_from.soonest_conf_deadline {
 618                         self.soonest_conf_deadline = merge_from.soonest_conf_deadline;
 619                 }
 620                 if self.feerate_previous > merge_from.feerate_previous {
 621                         self.feerate_previous = merge_from.feerate_previous;
 622                 }
 623                 self.height_timer = cmp::min(self.height_timer, merge_from.height_timer);
 624         }
 625         /// Gets the amount of all outptus being spent by this package, only valid for malleable
 626         /// packages.
 627         pub(crate) fn package_amount(&self) -> u64 {
 628                 let mut amounts = 0;
 629                 for (_, outp) in self.inputs.iter() {
 630                         amounts += outp.amount();
 631                 }
 632                 amounts
 633         }
 634         pub(crate) fn package_timelock(&self) -> u32 {
 635                 self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(self.height_original))
 636                         .max().expect("There must always be at least one output to spend in a PackageTemplate")
 637         }
 638         pub(crate) fn package_weight(&self, destination_script: &Script) -> usize {
 639                 let mut inputs_weight = 0;
 640                 let mut witnesses_weight = 2; // count segwit flags
 641                 for (_, outp) in self.inputs.iter() {
 642                         // previous_out_point: 36 bytes ; var_int: 1 byte ; sequence: 4 bytes
 643                         inputs_weight += 41 * WITNESS_SCALE_FACTOR;
 644                         witnesses_weight += outp.weight();
 645                 }
 646                 // version: 4 bytes ; count_tx_in: 1 byte ; count_tx_out: 1 byte ; lock_time: 4 bytes
 647                 let transaction_weight = 10 * WITNESS_SCALE_FACTOR;
 648                 // value: 8 bytes ; var_int: 1 byte ; pk_script: `destination_script.len()`
 649                 let output_weight = (8 + 1 + destination_script.len()) * WITNESS_SCALE_FACTOR;
 650                 inputs_weight + witnesses_weight + transaction_weight + output_weight
 651         }
 652         pub(crate) fn finalize_malleable_package<L: Deref, Signer: Sign>(
 653                 &self, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64, destination_script: Script, logger: &L
 654         ) -> Option<Transaction> where L::Target: Logger {
 655                 debug_assert!(self.is_malleable());
 656                 let mut bumped_tx = Transaction {
 657                         version: 2,
 658                         lock_time: PackedLockTime::ZERO,
 659                         input: vec![],
 660                         output: vec![TxOut {
 661                                 script_pubkey: destination_script,
 662                                 value,
 663                         }],
 664                 };
 665                 for (outpoint, _) in self.inputs.iter() {
 666                         bumped_tx.input.push(TxIn {
 667                                 previous_output: *outpoint,
 668                                 script_sig: Script::new(),
 669                                 sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
 670                                 witness: Witness::new(),
 671                         });
 672                 }
 673                 for (i, (outpoint, out)) in self.inputs.iter().enumerate() {
 674                         log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 675                         if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { return None; }
 676                 }
 677                 log_debug!(logger, "Finalized transaction {} ready to broadcast", bumped_tx.txid());
 678                 Some(bumped_tx)
 679         }
 680         pub(crate) fn finalize_untractable_package<L: Deref, Signer: Sign>(
 681                 &self, onchain_handler: &mut OnchainTxHandler<Signer>, logger: &L,
 682         ) -> Option<Transaction> where L::Target: Logger {
 683                 debug_assert!(!self.is_malleable());
 684                 if let Some((outpoint, outp)) = self.inputs.first() {
 685                         if let Some(final_tx) = outp.get_finalized_tx(outpoint, onchain_handler) {
 686                                 log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 687                                 log_debug!(logger, "Finalized transaction {} ready to broadcast", final_tx.txid());
 688                                 return Some(final_tx);
 689                         }
 690                         return None;
 691                 } else { panic!("API Error: Package must not be inputs empty"); }
 692         }
 693         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 694         /// 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
 695         /// height that once reached we should generate a new bumped "version" of the claim tx to be sure that we safely claim outputs before
 696         /// that our counterparty can do so. If timelock expires soon, height timer is going to be scaled down in consequence to increase
 697         /// frequency of the bump and so increase our bets of success.
 698         pub(crate) fn get_height_timer(&self, current_height: u32) -> u32 {
 699                 if self.soonest_conf_deadline <= current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL {
 700                         return current_height + HIGH_FREQUENCY_BUMP_INTERVAL
 701                 } else if self.soonest_conf_deadline - current_height <= LOW_FREQUENCY_BUMP_INTERVAL {
 702                         return current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL
 703                 }
 704                 current_height + LOW_FREQUENCY_BUMP_INTERVAL
 705         }
 706
 707         /// Returns value in satoshis to be included as package outgoing output amount and feerate
 708         /// which was used to generate the value. Will not return less than `dust_limit_sats` for the
 709         /// value.
 710         pub(crate) fn compute_package_output<F: Deref, L: Deref>(&self, predicted_weight: usize, dust_limit_sats: u64, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L) -> Option<(u64, u64)>
 711                 where F::Target: FeeEstimator,
 712                       L::Target: Logger,
 713         {
 714                 debug_assert!(self.malleability == PackageMalleability::Malleable, "The package output is fixed for non-malleable packages");
 715                 let input_amounts = self.package_amount();
 716                 assert!(dust_limit_sats as i64 > 0, "Output script must be broadcastable/have a 'real' dust limit.");
 717                 // If old feerate is 0, first iteration of this claim, use normal fee calculation
 718                 if self.feerate_previous != 0 {
 719                         if let Some((new_fee, feerate)) = feerate_bump(predicted_weight, input_amounts, self.feerate_previous, fee_estimator, logger) {
 720                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 721                         }
 722                 } else {
 723                         if let Some((new_fee, feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 724                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 725                         }
 726                 }
 727                 None
 728         }
 729
 730         #[cfg(anchors)]
 731         /// Computes a feerate based on the given confirmation target. If a previous feerate was used,
 732         /// and the new feerate is below it, we'll use a 25% increase of the previous feerate instead of
 733         /// the new one.
 734         pub(crate) fn compute_package_feerate<F: Deref>(
 735                 &self, fee_estimator: &LowerBoundedFeeEstimator<F>, conf_target: ConfirmationTarget,
 736         ) -> u32 where F::Target: FeeEstimator {
 737                 let feerate_estimate = fee_estimator.bounded_sat_per_1000_weight(conf_target);
 738                 if self.feerate_previous != 0 {
 739                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 740                         if feerate_estimate as u64 > self.feerate_previous {
 741                                 feerate_estimate
 742                         } else {
 743                                 // ...else just increase the previous feerate by 25% (because that's a nice number)
 744                                 (self.feerate_previous + (self.feerate_previous / 4)).try_into().unwrap_or(u32::max_value())
 745                         }
 746                 } else {
 747                         feerate_estimate
 748                 }
 749         }
 750
 751         /// Determines whether a package contains an input which must have additional external inputs
 752         /// attached to help the spending transaction reach confirmation.
 753         pub(crate) fn requires_external_funding(&self) -> bool {
 754                 self.inputs.iter().find(|input| match input.1 {
 755                         PackageSolvingData::HolderFundingOutput(ref outp) => outp.opt_anchors(),
 756                         PackageSolvingData::HolderHTLCOutput(ref outp) => outp.opt_anchors(),
 757                         _ => false,
 758                 }).is_some()
 759         }
 760
 761         pub (crate) fn build_package(txid: Txid, vout: u32, input_solving_data: PackageSolvingData, soonest_conf_deadline: u32, aggregable: bool, height_original: u32) -> Self {
 762                 let malleability = match input_solving_data {
 763                         PackageSolvingData::RevokedOutput(..) => PackageMalleability::Malleable,
 764                         PackageSolvingData::RevokedHTLCOutput(..) => PackageMalleability::Malleable,
 765                         PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => PackageMalleability::Malleable,
 766                         PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => PackageMalleability::Malleable,
 767                         PackageSolvingData::HolderHTLCOutput(ref outp) => if outp.opt_anchors() {
 768                                 PackageMalleability::Malleable
 769                         } else {
 770                                 PackageMalleability::Untractable
 771                         },
 772                         PackageSolvingData::HolderFundingOutput(..) => PackageMalleability::Untractable,
 773                 };
 774                 let mut inputs = Vec::with_capacity(1);
 775                 inputs.push((BitcoinOutPoint { txid, vout }, input_solving_data));
 776                 PackageTemplate {
 777                         inputs,
 778                         malleability,
 779                         soonest_conf_deadline,
 780                         aggregable,
 781                         feerate_previous: 0,
 782                         height_timer: None,
 783                         height_original,
 784                 }
 785         }
 786 }
 787
 788 impl Writeable for PackageTemplate {
 789         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 790                 writer.write_all(&(self.inputs.len() as u64).to_be_bytes())?;
 791                 for (ref outpoint, ref rev_outp) in self.inputs.iter() {
 792                         outpoint.write(writer)?;
 793                         rev_outp.write(writer)?;
 794                 }
 795                 write_tlv_fields!(writer, {
 796                         (0, self.soonest_conf_deadline, required),
 797                         (2, self.feerate_previous, required),
 798                         (4, self.height_original, required),
 799                         (6, self.height_timer, option)
 800                 });
 801                 Ok(())
 802         }
 803 }
 804
 805 impl Readable for PackageTemplate {
 806         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 807                 let inputs_count = <u64 as Readable>::read(reader)?;
 808                 let mut inputs: Vec<(BitcoinOutPoint, PackageSolvingData)> = Vec::with_capacity(cmp::min(inputs_count as usize, MAX_ALLOC_SIZE / 128));
 809                 for _ in 0..inputs_count {
 810                         let outpoint = Readable::read(reader)?;
 811                         let rev_outp = Readable::read(reader)?;
 812                         inputs.push((outpoint, rev_outp));
 813                 }
 814                 let (malleability, aggregable) = if let Some((_, lead_input)) = inputs.first() {
 815                         match lead_input {
 816                                 PackageSolvingData::RevokedOutput(..) => { (PackageMalleability::Malleable, true) },
 817                                 PackageSolvingData::RevokedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 818                                 PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 819                                 PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { (PackageMalleability::Malleable, false) },
 820                                 PackageSolvingData::HolderHTLCOutput(ref outp) => if outp.opt_anchors() {
 821                                         (PackageMalleability::Malleable, outp.preimage.is_some())
 822                                 } else {
 823                                         (PackageMalleability::Untractable, false)
 824                                 },
 825                                 PackageSolvingData::HolderFundingOutput(..) => { (PackageMalleability::Untractable, false) },
 826                         }
 827                 } else { return Err(DecodeError::InvalidValue); };
 828                 let mut soonest_conf_deadline = 0;
 829                 let mut feerate_previous = 0;
 830                 let mut height_timer = None;
 831                 let mut height_original = 0;
 832                 read_tlv_fields!(reader, {
 833                         (0, soonest_conf_deadline, required),
 834                         (2, feerate_previous, required),
 835                         (4, height_original, required),
 836                         (6, height_timer, option),
 837                 });
 838                 Ok(PackageTemplate {
 839                         inputs,
 840                         malleability,
 841                         soonest_conf_deadline,
 842                         aggregable,
 843                         feerate_previous,
 844                         height_timer,
 845                         height_original,
 846                 })
 847         }
 848 }
 849
 850 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 851 /// weight. We start with the highest priority feerate returned by the node's fee estimator then
 852 /// fall-back to lower priorities until we have enough value available to suck from.
 853 ///
 854 /// If the proposed fee is less than the available spent output's values, we return the proposed
 855 /// fee and the corresponding updated feerate. If the proposed fee is equal or more than the
 856 /// available spent output's values, we return nothing
 857 fn compute_fee_from_spent_amounts<F: Deref, L: Deref>(input_amounts: u64, predicted_weight: usize, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L) -> Option<(u64, u64)>
 858         where F::Target: FeeEstimator,
 859               L::Target: Logger,
 860 {
 861         let mut updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64;
 862         let mut fee = updated_feerate * (predicted_weight as u64) / 1000;
 863         if input_amounts <= fee {
 864                 updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal) as u64;
 865                 fee = updated_feerate * (predicted_weight as u64) / 1000;
 866                 if input_amounts <= fee {
 867                         updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background) as u64;
 868                         fee = updated_feerate * (predicted_weight as u64) / 1000;
 869                         if input_amounts <= fee {
 870                                 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)",
 871                                         fee, input_amounts);
 872                                 None
 873                         } else {
 874                                 log_warn!(logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 875                                         input_amounts);
 876                                 Some((fee, updated_feerate))
 877                         }
 878                 } else {
 879                         log_warn!(logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 880                                 input_amounts);
 881                         Some((fee, updated_feerate))
 882                 }
 883         } else {
 884                 Some((fee, updated_feerate))
 885         }
 886 }
 887
 888 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 889 /// weight. If feerates proposed by the fee-estimator have been increasing since last fee-bumping
 890 /// attempt, use them. Otherwise, blindly bump the feerate by 25% of the previous feerate. We also
 891 /// verify that those bumping heuristics respect BIP125 rules 3) and 4) and if required adjust
 892 /// the new fee to meet the RBF policy requirement.
 893 fn feerate_bump<F: Deref, L: Deref>(predicted_weight: usize, input_amounts: u64, previous_feerate: u64, fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L) -> Option<(u64, u64)>
 894         where F::Target: FeeEstimator,
 895               L::Target: Logger,
 896 {
 897         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 898         let new_fee = if let Some((new_fee, _)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 899                 let updated_feerate = new_fee / (predicted_weight as u64 * 1000);
 900                 if updated_feerate > previous_feerate {
 901                         new_fee
 902                 } else {
 903                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 904                         let new_fee = previous_feerate * (predicted_weight as u64) / 750;
 905                         if input_amounts <= new_fee {
 906                                 log_warn!(logger, "Can't 25% bump new claiming tx, amount {} is too small", input_amounts);
 907                                 return None;
 908                         }
 909                         new_fee
 910                 }
 911         } else {
 912                 log_warn!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", input_amounts);
 913                 return None;
 914         };
 915
 916         let previous_fee = previous_feerate * (predicted_weight as u64) / 1000;
 917         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * (predicted_weight as u64) / 1000;
 918         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 919         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 920         //      * 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.
 921         let new_fee = if new_fee < previous_fee + min_relay_fee {
 922                 new_fee + previous_fee + min_relay_fee - new_fee
 923         } else {
 924                 new_fee
 925         };
 926         Some((new_fee, new_fee * 1000 / (predicted_weight as u64)))
 927 }
 928
 929 #[cfg(test)]
 930 mod tests {
 931         use crate::chain::package::{CounterpartyOfferedHTLCOutput, CounterpartyReceivedHTLCOutput, HolderHTLCOutput, PackageTemplate, PackageSolvingData, RevokedOutput, WEIGHT_REVOKED_OUTPUT, weight_offered_htlc, weight_received_htlc};
 932         use crate::chain::Txid;
 933         use crate::ln::chan_utils::HTLCOutputInCommitment;
 934         use crate::ln::{PaymentPreimage, PaymentHash};
 935
 936         use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
 937         use bitcoin::blockdata::script::Script;
 938         use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
 939
 940         use bitcoin::hashes::hex::FromHex;
 941
 942         use bitcoin::secp256k1::{PublicKey,SecretKey};
 943         use bitcoin::secp256k1::Secp256k1;
 944
 945         macro_rules! dumb_revk_output {
 946                 ($secp_ctx: expr) => {
 947                         {
 948                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 949                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 950                                 PackageSolvingData::RevokedOutput(RevokedOutput::build(dumb_point, dumb_point, dumb_point, dumb_scalar, 0, 0))
 951                         }
 952                 }
 953         }
 954
 955         macro_rules! dumb_counterparty_output {
 956                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
 957                         {
 958                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 959                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 960                                 let hash = PaymentHash([1; 32]);
 961                                 let htlc = HTLCOutputInCommitment { offered: true, amount_msat: $amt, cltv_expiry: 0, payment_hash: hash, transaction_output_index: None };
 962                                 PackageSolvingData::CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput::build(dumb_point, dumb_point, dumb_point, htlc, $opt_anchors))
 963                         }
 964                 }
 965         }
 966
 967         macro_rules! dumb_counterparty_offered_output {
 968                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
 969                         {
 970                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 971                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 972                                 let hash = PaymentHash([1; 32]);
 973                                 let preimage = PaymentPreimage([2;32]);
 974                                 let htlc = HTLCOutputInCommitment { offered: false, amount_msat: $amt, cltv_expiry: 1000, payment_hash: hash, transaction_output_index: None };
 975                                 PackageSolvingData::CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput::build(dumb_point, dumb_point, dumb_point, preimage, htlc, $opt_anchors))
 976                         }
 977                 }
 978         }
 979
 980         macro_rules! dumb_htlc_output {
 981                 () => {
 982                         {
 983                                 let preimage = PaymentPreimage([2;32]);
 984                                 PackageSolvingData::HolderHTLCOutput(HolderHTLCOutput::build_accepted(preimage, 0, false))
 985                         }
 986                 }
 987         }
 988
 989         #[test]
 990         #[should_panic]
 991         fn test_package_differing_heights() {
 992                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
 993                 let secp_ctx = Secp256k1::new();
 994                 let revk_outp = dumb_revk_output!(secp_ctx);
 995
 996                 let mut package_one_hundred = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
 997                 let package_two_hundred = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 200);
 998                 package_one_hundred.merge_package(package_two_hundred);
 999         }
1000
1001         #[test]
1002         #[should_panic]
1003         fn test_package_untractable_merge_to() {
1004                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1005                 let secp_ctx = Secp256k1::new();
1006                 let revk_outp = dumb_revk_output!(secp_ctx);
1007                 let htlc_outp = dumb_htlc_output!();
1008
1009                 let mut untractable_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1010                 let malleable_package = PackageTemplate::build_package(txid, 1, htlc_outp.clone(), 1000, true, 100);
1011                 untractable_package.merge_package(malleable_package);
1012         }
1013
1014         #[test]
1015         #[should_panic]
1016         fn test_package_untractable_merge_from() {
1017                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1018                 let secp_ctx = Secp256k1::new();
1019                 let htlc_outp = dumb_htlc_output!();
1020                 let revk_outp = dumb_revk_output!(secp_ctx);
1021
1022                 let mut malleable_package = PackageTemplate::build_package(txid, 0, htlc_outp.clone(), 1000, true, 100);
1023                 let untractable_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1024                 malleable_package.merge_package(untractable_package);
1025         }
1026
1027         #[test]
1028         #[should_panic]
1029         fn test_package_noaggregation_to() {
1030                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1031                 let secp_ctx = Secp256k1::new();
1032                 let revk_outp = dumb_revk_output!(secp_ctx);
1033
1034                 let mut noaggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, false, 100);
1035                 let aggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1036                 noaggregation_package.merge_package(aggregation_package);
1037         }
1038
1039         #[test]
1040         #[should_panic]
1041         fn test_package_noaggregation_from() {
1042                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1043                 let secp_ctx = Secp256k1::new();
1044                 let revk_outp = dumb_revk_output!(secp_ctx);
1045
1046                 let mut aggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1047                 let noaggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, false, 100);
1048                 aggregation_package.merge_package(noaggregation_package);
1049         }
1050
1051         #[test]
1052         #[should_panic]
1053         fn test_package_empty() {
1054                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1055                 let secp_ctx = Secp256k1::new();
1056                 let revk_outp = dumb_revk_output!(secp_ctx);
1057
1058                 let mut empty_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1059                 empty_package.inputs = vec![];
1060                 let package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1061                 empty_package.merge_package(package);
1062         }
1063
1064         #[test]
1065         #[should_panic]
1066         fn test_package_differing_categories() {
1067                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1068                 let secp_ctx = Secp256k1::new();
1069                 let revk_outp = dumb_revk_output!(secp_ctx);
1070                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 0, false);
1071
1072                 let mut revoked_package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1073                 let counterparty_package = PackageTemplate::build_package(txid, 1, counterparty_outp, 1000, true, 100);
1074                 revoked_package.merge_package(counterparty_package);
1075         }
1076
1077         #[test]
1078         fn test_package_split_malleable() {
1079                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1080                 let secp_ctx = Secp256k1::new();
1081                 let revk_outp_one = dumb_revk_output!(secp_ctx);
1082                 let revk_outp_two = dumb_revk_output!(secp_ctx);
1083                 let revk_outp_three = dumb_revk_output!(secp_ctx);
1084
1085                 let mut package_one = PackageTemplate::build_package(txid, 0, revk_outp_one, 1000, true, 100);
1086                 let package_two = PackageTemplate::build_package(txid, 1, revk_outp_two, 1000, true, 100);
1087                 let package_three = PackageTemplate::build_package(txid, 2, revk_outp_three, 1000, true, 100);
1088
1089                 package_one.merge_package(package_two);
1090                 package_one.merge_package(package_three);
1091                 assert_eq!(package_one.outpoints().len(), 3);
1092
1093                 if let Some(split_package) = package_one.split_package(&BitcoinOutPoint { txid, vout: 1 }) {
1094                         // Packages attributes should be identical
1095                         assert!(split_package.is_malleable());
1096                         assert_eq!(split_package.soonest_conf_deadline, package_one.soonest_conf_deadline);
1097                         assert_eq!(split_package.aggregable, package_one.aggregable);
1098                         assert_eq!(split_package.feerate_previous, package_one.feerate_previous);
1099                         assert_eq!(split_package.height_timer, package_one.height_timer);
1100                         assert_eq!(split_package.height_original, package_one.height_original);
1101                 } else { panic!(); }
1102                 assert_eq!(package_one.outpoints().len(), 2);
1103         }
1104
1105         #[test]
1106         fn test_package_split_untractable() {
1107                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1108                 let htlc_outp_one = dumb_htlc_output!();
1109
1110                 let mut package_one = PackageTemplate::build_package(txid, 0, htlc_outp_one, 1000, true, 100);
1111                 let ret_split = package_one.split_package(&BitcoinOutPoint { txid, vout: 0});
1112                 assert!(ret_split.is_none());
1113         }
1114
1115         #[test]
1116         fn test_package_timer() {
1117                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1118                 let secp_ctx = Secp256k1::new();
1119                 let revk_outp = dumb_revk_output!(secp_ctx);
1120
1121                 let mut package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1122                 let timer_none = package.timer();
1123                 assert!(timer_none.is_none());
1124                 package.set_timer(Some(100));
1125                 if let Some(timer_some) = package.timer() {
1126                         assert_eq!(timer_some, 100);
1127                 } else { panic!() }
1128         }
1129
1130         #[test]
1131         fn test_package_amounts() {
1132                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1133                 let secp_ctx = Secp256k1::new();
1134                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, false);
1135
1136                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1137                 assert_eq!(package.package_amount(), 1000);
1138         }
1139
1140         #[test]
1141         fn test_package_weight() {
1142                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1143                 let secp_ctx = Secp256k1::new();
1144
1145                 // (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 + witness marker (2)
1146                 let weight_sans_output = (4 + 4 + 1 + 36 + 4 + 1 + 1 + 8 + 1) * WITNESS_SCALE_FACTOR + 2;
1147
1148                 {
1149                         let revk_outp = dumb_revk_output!(secp_ctx);
1150                         let package = PackageTemplate::build_package(txid, 0, revk_outp, 0, true, 100);
1151                         assert_eq!(package.package_weight(&Script::new()),  weight_sans_output + WEIGHT_REVOKED_OUTPUT as usize);
1152                 }
1153
1154                 {
1155                         for &opt_anchors in [false, true].iter() {
1156                                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, opt_anchors);
1157                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1158                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_received_htlc(opt_anchors) as usize);
1159                         }
1160                 }
1161
1162                 {
1163                         for &opt_anchors in [false, true].iter() {
1164                                 let counterparty_outp = dumb_counterparty_offered_output!(secp_ctx, 1_000_000, opt_anchors);
1165                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1166                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_offered_htlc(opt_anchors) as usize);
1167                         }
1168                 }
1169         }
1170 }