_ 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::byte_utils;
  31 use crate::util::logger::Logger;
  32 use crate::util::ser::{Readable, Writer, Writeable};
  33
  34 use crate::io;
  35 use crate::prelude::*;
  36 use core::cmp;
  37 #[cfg(anchors)]
  38 use core::convert::TryInto;
  39 use core::mem;
  40 use core::ops::Deref;
  41 use bitcoin::{PackedLockTime, Sequence, Witness};
  42
  43 use super::chaininterface::LowerBoundedFeeEstimator;
  44
  45 const MAX_ALLOC_SIZE: usize = 64*1024;
  46
  47
  48 pub(crate) fn weight_revoked_offered_htlc(opt_anchors: bool) -> u64 {
  49         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  50         const WEIGHT_REVOKED_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 + 133;
  51         const WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  52         if opt_anchors { WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS } else { WEIGHT_REVOKED_OFFERED_HTLC }
  53 }
  54
  55 pub(crate) fn weight_revoked_received_htlc(opt_anchors: bool) -> u64 {
  56         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  57         const WEIGHT_REVOKED_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 +  139;
  58         const WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  59         if opt_anchors { WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS } else { WEIGHT_REVOKED_RECEIVED_HTLC }
  60 }
  61
  62 pub(crate) fn weight_offered_htlc(opt_anchors: bool) -> u64 {
  63         // number_of_witness_elements + sig_length + counterpartyhtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
  64         const WEIGHT_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 32 + 1 + 133;
  65         const WEIGHT_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  66         if opt_anchors { WEIGHT_OFFERED_HTLC_ANCHORS } else { WEIGHT_OFFERED_HTLC }
  67 }
  68
  69 pub(crate) fn weight_received_htlc(opt_anchors: bool) -> u64 {
  70         // number_of_witness_elements + sig_length + counterpartyhtlc_sig + empty_vec_length + empty_vec + witness_script_length + witness_script
  71         const WEIGHT_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 139;
  72         const WEIGHT_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  73         if opt_anchors { WEIGHT_RECEIVED_HTLC_ANCHORS } else { WEIGHT_RECEIVED_HTLC }
  74 }
  75
  76 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
  77 pub(crate) const WEIGHT_REVOKED_OUTPUT: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 77;
  78
  79 /// Height delay at which transactions are fee-bumped/rebroadcasted with a low priority.
  80 const LOW_FREQUENCY_BUMP_INTERVAL: u32 = 15;
  81 /// Height delay at which transactions are fee-bumped/rebroadcasted with a middle priority.
  82 const MIDDLE_FREQUENCY_BUMP_INTERVAL: u32 = 3;
  83 /// Height delay at which transactions are fee-bumped/rebroadcasted with a high priority.
  84 const HIGH_FREQUENCY_BUMP_INTERVAL: u32 = 1;
  85
  86 /// A struct to describe a revoked output and corresponding information to generate a solving
  87 /// witness spending a commitment `to_local` output or a second-stage HTLC transaction output.
  88 ///
  89 /// CSV and pubkeys are used as part of a witnessScript redeeming a balance output, amount is used
  90 /// as part of the signature hash and revocation secret to generate a satisfying witness.
  91 #[derive(Clone, PartialEq, Eq)]
  92 pub(crate) struct RevokedOutput {
  93         per_commitment_point: PublicKey,
  94         counterparty_delayed_payment_base_key: PublicKey,
  95         counterparty_htlc_base_key: PublicKey,
  96         per_commitment_key: SecretKey,
  97         weight: u64,
  98         amount: u64,
  99         on_counterparty_tx_csv: u16,
 100 }
 101
 102 impl RevokedOutput {
 103         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 {
 104                 RevokedOutput {
 105                         per_commitment_point,
 106                         counterparty_delayed_payment_base_key,
 107                         counterparty_htlc_base_key,
 108                         per_commitment_key,
 109                         weight: WEIGHT_REVOKED_OUTPUT,
 110                         amount,
 111                         on_counterparty_tx_csv
 112                 }
 113         }
 114 }
 115
 116 impl_writeable_tlv_based!(RevokedOutput, {
 117         (0, per_commitment_point, required),
 118         (2, counterparty_delayed_payment_base_key, required),
 119         (4, counterparty_htlc_base_key, required),
 120         (6, per_commitment_key, required),
 121         (8, weight, required),
 122         (10, amount, required),
 123         (12, on_counterparty_tx_csv, required),
 124 });
 125
 126 /// A struct to describe a revoked offered output and corresponding information to generate a
 127 /// solving witness.
 128 ///
 129 /// HTLCOuputInCommitment (hash timelock, direction) and pubkeys are used to generate a suitable
 130 /// witnessScript.
 131 ///
 132 /// CSV is used as part of a witnessScript redeeming a balance output, amount is used as part
 133 /// of the signature hash and revocation secret to generate a satisfying witness.
 134 #[derive(Clone, PartialEq, Eq)]
 135 pub(crate) struct RevokedHTLCOutput {
 136         per_commitment_point: PublicKey,
 137         counterparty_delayed_payment_base_key: PublicKey,
 138         counterparty_htlc_base_key: PublicKey,
 139         per_commitment_key: SecretKey,
 140         weight: u64,
 141         amount: u64,
 142         htlc: HTLCOutputInCommitment,
 143 }
 144
 145 impl RevokedHTLCOutput {
 146         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 {
 147                 let weight = if htlc.offered { weight_revoked_offered_htlc(opt_anchors) } else { weight_revoked_received_htlc(opt_anchors) };
 148                 RevokedHTLCOutput {
 149                         per_commitment_point,
 150                         counterparty_delayed_payment_base_key,
 151                         counterparty_htlc_base_key,
 152                         per_commitment_key,
 153                         weight,
 154                         amount,
 155                         htlc
 156                 }
 157         }
 158 }
 159
 160 impl_writeable_tlv_based!(RevokedHTLCOutput, {
 161         (0, per_commitment_point, required),
 162         (2, counterparty_delayed_payment_base_key, required),
 163         (4, counterparty_htlc_base_key, required),
 164         (6, per_commitment_key, required),
 165         (8, weight, required),
 166         (10, amount, required),
 167         (12, htlc, required),
 168 });
 169
 170 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 171 ///
 172 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 173 /// witnessScript.
 174 ///
 175 /// The preimage is used as part of the witness.
 176 #[derive(Clone, PartialEq, Eq)]
 177 pub(crate) struct CounterpartyOfferedHTLCOutput {
 178         per_commitment_point: PublicKey,
 179         counterparty_delayed_payment_base_key: PublicKey,
 180         counterparty_htlc_base_key: PublicKey,
 181         preimage: PaymentPreimage,
 182         htlc: HTLCOutputInCommitment,
 183         opt_anchors: Option<()>,
 184 }
 185
 186 impl CounterpartyOfferedHTLCOutput {
 187         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 {
 188                 CounterpartyOfferedHTLCOutput {
 189                         per_commitment_point,
 190                         counterparty_delayed_payment_base_key,
 191                         counterparty_htlc_base_key,
 192                         preimage,
 193                         htlc,
 194                         opt_anchors: if opt_anchors { Some(()) } else { None },
 195                 }
 196         }
 197
 198         fn opt_anchors(&self) -> bool {
 199                 self.opt_anchors.is_some()
 200         }
 201 }
 202
 203 impl_writeable_tlv_based!(CounterpartyOfferedHTLCOutput, {
 204         (0, per_commitment_point, required),
 205         (1, opt_anchors, option),
 206         (2, counterparty_delayed_payment_base_key, required),
 207         (4, counterparty_htlc_base_key, required),
 208         (6, preimage, required),
 209         (8, htlc, required),
 210 });
 211
 212 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 213 ///
 214 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 215 /// witnessScript.
 216 #[derive(Clone, PartialEq, Eq)]
 217 pub(crate) struct CounterpartyReceivedHTLCOutput {
 218         per_commitment_point: PublicKey,
 219         counterparty_delayed_payment_base_key: PublicKey,
 220         counterparty_htlc_base_key: PublicKey,
 221         htlc: HTLCOutputInCommitment,
 222         opt_anchors: Option<()>,
 223 }
 224
 225 impl CounterpartyReceivedHTLCOutput {
 226         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 {
 227                 CounterpartyReceivedHTLCOutput {
 228                         per_commitment_point,
 229                         counterparty_delayed_payment_base_key,
 230                         counterparty_htlc_base_key,
 231                         htlc,
 232                         opt_anchors: if opt_anchors { Some(()) } else { None },
 233                 }
 234         }
 235
 236         fn opt_anchors(&self) -> bool {
 237                 self.opt_anchors.is_some()
 238         }
 239 }
 240
 241 impl_writeable_tlv_based!(CounterpartyReceivedHTLCOutput, {
 242         (0, per_commitment_point, required),
 243         (1, opt_anchors, option),
 244         (2, counterparty_delayed_payment_base_key, required),
 245         (4, counterparty_htlc_base_key, required),
 246         (6, htlc, required),
 247 });
 248
 249 /// A struct to describe a HTLC output on holder commitment transaction.
 250 ///
 251 /// Either offered or received, the amount is always used as part of the bip143 sighash.
 252 /// Preimage is only included as part of the witness in former case.
 253 #[derive(Clone, PartialEq, Eq)]
 254 pub(crate) struct HolderHTLCOutput {
 255         preimage: Option<PaymentPreimage>,
 256         amount: u64,
 257         /// Defaults to 0 for HTLC-Success transactions, which have no expiry
 258         cltv_expiry: u32,
 259 }
 260
 261 impl HolderHTLCOutput {
 262         pub(crate) fn build_offered(amount: u64, cltv_expiry: u32) -> Self {
 263                 HolderHTLCOutput {
 264                         preimage: None,
 265                         amount,
 266                         cltv_expiry,
 267                 }
 268         }
 269
 270         pub(crate) fn build_accepted(preimage: PaymentPreimage, amount: u64) -> Self {
 271                 HolderHTLCOutput {
 272                         preimage: Some(preimage),
 273                         amount,
 274                         cltv_expiry: 0,
 275                 }
 276         }
 277 }
 278
 279 impl_writeable_tlv_based!(HolderHTLCOutput, {
 280         (0, amount, required),
 281         (2, cltv_expiry, required),
 282         (4, preimage, option)
 283 });
 284
 285 /// A struct to describe the channel output on the funding transaction.
 286 ///
 287 /// witnessScript is used as part of the witness redeeming the funding utxo.
 288 #[derive(Clone, PartialEq, Eq)]
 289 pub(crate) struct HolderFundingOutput {
 290         funding_redeemscript: Script,
 291         funding_amount: Option<u64>,
 292         opt_anchors: Option<()>,
 293 }
 294
 295
 296 impl HolderFundingOutput {
 297         pub(crate) fn build(funding_redeemscript: Script, funding_amount: u64, opt_anchors: bool) -> Self {
 298                 HolderFundingOutput {
 299                         funding_redeemscript,
 300                         funding_amount: Some(funding_amount),
 301                         opt_anchors: if opt_anchors { Some(()) } else { None },
 302                 }
 303         }
 304
 305         fn opt_anchors(&self) -> bool {
 306                 self.opt_anchors.is_some()
 307         }
 308 }
 309
 310 impl_writeable_tlv_based!(HolderFundingOutput, {
 311         (0, funding_redeemscript, required),
 312         (1, opt_anchors, option),
 313         (3, funding_amount, option),
 314 });
 315
 316 /// A wrapper encapsulating all in-protocol differing outputs types.
 317 ///
 318 /// The generic API offers access to an outputs common attributes or allow transformation such as
 319 /// finalizing an input claiming the output.
 320 #[derive(Clone, PartialEq, Eq)]
 321 pub(crate) enum PackageSolvingData {
 322         RevokedOutput(RevokedOutput),
 323         RevokedHTLCOutput(RevokedHTLCOutput),
 324         CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput),
 325         CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput),
 326         HolderHTLCOutput(HolderHTLCOutput),
 327         HolderFundingOutput(HolderFundingOutput),
 328 }
 329
 330 impl PackageSolvingData {
 331         fn amount(&self) -> u64 {
 332                 let amt = match self {
 333                         PackageSolvingData::RevokedOutput(ref outp) => outp.amount,
 334                         PackageSolvingData::RevokedHTLCOutput(ref outp) => outp.amount,
 335                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 336                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 337                         // Note: Currently, amounts of holder outputs spending witnesses aren't used
 338                         // as we can't malleate spending package to increase their feerate. This
 339                         // should change with the remaining anchor output patchset.
 340                         PackageSolvingData::HolderHTLCOutput(..) => unreachable!(),
 341                         PackageSolvingData::HolderFundingOutput(ref outp) => {
 342                                 debug_assert!(outp.opt_anchors());
 343                                 outp.funding_amount.unwrap()
 344                         }
 345                 };
 346                 amt
 347         }
 348         fn weight(&self) -> usize {
 349                 let weight = match self {
 350                         PackageSolvingData::RevokedOutput(ref outp) => { outp.weight as usize },
 351                         PackageSolvingData::RevokedHTLCOutput(ref outp) => { outp.weight as usize },
 352                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => { weight_offered_htlc(outp.opt_anchors()) as usize },
 353                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => { weight_received_htlc(outp.opt_anchors()) as usize },
 354                         // Note: Currently, weights of holder outputs spending witnesses aren't used
 355                         // as we can't malleate spending package to increase their feerate. This
 356                         // should change with the remaining anchor output patchset.
 357                         PackageSolvingData::HolderHTLCOutput(..) => { unreachable!() },
 358                         PackageSolvingData::HolderFundingOutput(..) => { unreachable!() },
 359                 };
 360                 weight
 361         }
 362         fn is_compatible(&self, input: &PackageSolvingData) -> bool {
 363                 match self {
 364                         PackageSolvingData::RevokedOutput(..) => {
 365                                 match input {
 366                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 367                                         PackageSolvingData::RevokedOutput(..) => { true },
 368                                         _ => { false }
 369                                 }
 370                         },
 371                         PackageSolvingData::RevokedHTLCOutput(..) => {
 372                                 match input {
 373                                         PackageSolvingData::RevokedOutput(..) => { true },
 374                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 375                                         _ => { false }
 376                                 }
 377                         },
 378                         _ => { mem::discriminant(self) == mem::discriminant(&input) }
 379                 }
 380         }
 381         fn finalize_input<Signer: Sign>(&self, bumped_tx: &mut Transaction, i: usize, onchain_handler: &mut OnchainTxHandler<Signer>) -> bool {
 382                 match self {
 383                         PackageSolvingData::RevokedOutput(ref outp) => {
 384                                 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) {
 385                                         let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key);
 386                                         //TODO: should we panic on signer failure ?
 387                                         if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) {
 388                                                 let mut ser_sig = sig.serialize_der().to_vec();
 389                                                 ser_sig.push(EcdsaSighashType::All as u8);
 390                                                 bumped_tx.input[i].witness.push(ser_sig);
 391                                                 bumped_tx.input[i].witness.push(vec!(1));
 392                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 393                                         } else { return false; }
 394                                 }
 395                         },
 396                         PackageSolvingData::RevokedHTLCOutput(ref outp) => {
 397                                 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) {
 398                                         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);
 399                                         //TODO: should we panic on signer failure ?
 400                                         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) {
 401                                                 let mut ser_sig = sig.serialize_der().to_vec();
 402                                                 ser_sig.push(EcdsaSighashType::All as u8);
 403                                                 bumped_tx.input[i].witness.push(ser_sig);
 404                                                 bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
 405                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 406                                         } else { return false; }
 407                                 }
 408                         },
 409                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => {
 410                                 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) {
 411                                         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);
 412
 413                                         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) {
 414                                                 let mut ser_sig = sig.serialize_der().to_vec();
 415                                                 ser_sig.push(EcdsaSighashType::All as u8);
 416                                                 bumped_tx.input[i].witness.push(ser_sig);
 417                                                 bumped_tx.input[i].witness.push(outp.preimage.0.to_vec());
 418                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 419                                         }
 420                                 }
 421                         },
 422                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => {
 423                                 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) {
 424                                         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);
 425
 426                                         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
 427                                         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) {
 428                                                 let mut ser_sig = sig.serialize_der().to_vec();
 429                                                 ser_sig.push(EcdsaSighashType::All as u8);
 430                                                 bumped_tx.input[i].witness.push(ser_sig);
 431                                                 // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
 432                                                 bumped_tx.input[i].witness.push(vec![]);
 433                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 434                                         }
 435                                 }
 436                         },
 437                         _ => { panic!("API Error!"); }
 438                 }
 439                 true
 440         }
 441         fn get_finalized_tx<Signer: Sign>(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler<Signer>) -> Option<Transaction> {
 442                 match self {
 443                         PackageSolvingData::HolderHTLCOutput(ref outp) => { return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage); }
 444                         PackageSolvingData::HolderFundingOutput(ref outp) => { return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript)); }
 445                         _ => { panic!("API Error!"); }
 446                 }
 447         }
 448         fn absolute_tx_timelock(&self, output_conf_height: u32) -> u32 {
 449                 // Get the absolute timelock at which this output can be spent given the height at which
 450                 // this output was confirmed. We use `output_conf_height + 1` as a safe default as we can
 451                 // be confirmed in the next block and transactions with time lock `current_height + 1`
 452                 // always propagate.
 453                 let absolute_timelock = match self {
 454                         PackageSolvingData::RevokedOutput(_) => output_conf_height + 1,
 455                         PackageSolvingData::RevokedHTLCOutput(_) => output_conf_height + 1,
 456                         PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => output_conf_height + 1,
 457                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
 458                         PackageSolvingData::HolderHTLCOutput(ref outp) => cmp::max(outp.cltv_expiry, output_conf_height + 1),
 459                         PackageSolvingData::HolderFundingOutput(_) => output_conf_height + 1,
 460                 };
 461                 absolute_timelock
 462         }
 463 }
 464
 465 impl_writeable_tlv_based_enum!(PackageSolvingData, ;
 466         (0, RevokedOutput),
 467         (1, RevokedHTLCOutput),
 468         (2, CounterpartyOfferedHTLCOutput),
 469         (3, CounterpartyReceivedHTLCOutput),
 470         (4, HolderHTLCOutput),
 471         (5, HolderFundingOutput),
 472 );
 473
 474 /// A malleable package might be aggregated with other packages to save on fees.
 475 /// A untractable package has been counter-signed and aggregable will break cached counterparty
 476 /// signatures.
 477 #[derive(Clone, PartialEq, Eq)]
 478 pub(crate) enum PackageMalleability {
 479         Malleable,
 480         Untractable,
 481 }
 482
 483 /// A structure to describe a package content that is generated by ChannelMonitor and
 484 /// used by OnchainTxHandler to generate and broadcast transactions settling onchain claims.
 485 ///
 486 /// A package is defined as one or more transactions claiming onchain outputs in reaction
 487 /// to confirmation of a channel transaction. Those packages might be aggregated to save on
 488 /// fees, if satisfaction of outputs's witnessScript let's us do so.
 489 ///
 490 /// As packages are time-sensitive, we fee-bump and rebroadcast them at scheduled intervals.
 491 /// Failing to confirm a package translate as a loss of funds for the user.
 492 #[derive(Clone, PartialEq, Eq)]
 493 pub struct PackageTemplate {
 494         // List of onchain outputs and solving data to generate satisfying witnesses.
 495         inputs: Vec<(BitcoinOutPoint, PackageSolvingData)>,
 496         // Packages are deemed as malleable if we have local knwoledge of at least one set of
 497         // private keys yielding a satisfying witnesses. Malleability implies that we can aggregate
 498         // packages among them to save on fees or rely on RBF to bump their feerates.
 499         // Untractable packages have been counter-signed and thus imply that we can't aggregate
 500         // them without breaking signatures. Fee-bumping strategy will also rely on CPFP.
 501         malleability: PackageMalleability,
 502         // Block height after which the earlier-output belonging to this package is mature for a
 503         // competing claim by the counterparty. As our chain tip becomes nearer from the timelock,
 504         // the fee-bumping frequency will increase. See `OnchainTxHandler::get_height_timer`.
 505         soonest_conf_deadline: u32,
 506         // Determines if this package can be aggregated.
 507         // Timelocked outputs belonging to the same transaction might have differing
 508         // satisfying heights. Picking up the later height among the output set would be a valid
 509         // aggregable strategy but it comes with at least 2 trade-offs :
 510         // * earlier-output fund are going to take longer to come back
 511         // * CLTV delta backing up a corresponding HTLC on an upstream channel could be swallowed
 512         // by the requirement of the later-output part of the set
 513         // For now, we mark such timelocked outputs as non-aggregable, though we might introduce
 514         // smarter aggregable strategy in the future.
 515         aggregable: bool,
 516         // Cache of package feerate committed at previous (re)broadcast. If bumping resources
 517         // (either claimed output value or external utxo), it will keep increasing until holder
 518         // or counterparty successful claim.
 519         feerate_previous: u64,
 520         // Cache of next height at which fee-bumping and rebroadcast will be attempted. In
 521         // the future, we might abstract it to an observed mempool fluctuation.
 522         height_timer: Option<u32>,
 523         // Confirmation height of the claimed outputs set transaction. In case of reorg reaching
 524         // it, we wipe out and forget the package.
 525         height_original: u32,
 526 }
 527
 528 impl PackageTemplate {
 529         pub(crate) fn is_malleable(&self) -> bool {
 530                 self.malleability == PackageMalleability::Malleable
 531         }
 532         pub(crate) fn timelock(&self) -> u32 {
 533                 self.soonest_conf_deadline
 534         }
 535         pub(crate) fn aggregable(&self) -> bool {
 536                 self.aggregable
 537         }
 538         pub(crate) fn set_feerate(&mut self, new_feerate: u64) {
 539                 self.feerate_previous = new_feerate;
 540         }
 541         pub(crate) fn timer(&self) -> Option<u32> {
 542                 if let Some(ref timer) = self.height_timer {
 543                         return Some(*timer);
 544                 }
 545                 None
 546         }
 547         pub(crate) fn set_timer(&mut self, new_timer: Option<u32>) {
 548                 self.height_timer = new_timer;
 549         }
 550         pub(crate) fn outpoints(&self) -> Vec<&BitcoinOutPoint> {
 551                 self.inputs.iter().map(|(o, _)| o).collect()
 552         }
 553         pub(crate) fn inputs(&self) -> impl ExactSizeIterator<Item = &PackageSolvingData> {
 554                 self.inputs.iter().map(|(_, i)| i)
 555         }
 556         pub(crate) fn split_package(&mut self, split_outp: &BitcoinOutPoint) -> Option<PackageTemplate> {
 557                 match self.malleability {
 558                         PackageMalleability::Malleable => {
 559                                 let mut split_package = None;
 560                                 let timelock = self.soonest_conf_deadline;
 561                                 let aggregable = self.aggregable;
 562                                 let feerate_previous = self.feerate_previous;
 563                                 let height_timer = self.height_timer;
 564                                 let height_original = self.height_original;
 565                                 self.inputs.retain(|outp| {
 566                                         if *split_outp == outp.0 {
 567                                                 split_package = Some(PackageTemplate {
 568                                                         inputs: vec![(outp.0, outp.1.clone())],
 569                                                         malleability: PackageMalleability::Malleable,
 570                                                         soonest_conf_deadline: timelock,
 571                                                         aggregable,
 572                                                         feerate_previous,
 573                                                         height_timer,
 574                                                         height_original,
 575                                                 });
 576                                                 return false;
 577                                         }
 578                                         return true;
 579                                 });
 580                                 return split_package;
 581                         },
 582                         _ => {
 583                                 // Note, we may try to split on remote transaction for
 584                                 // which we don't have a competing one (HTLC-Success before
 585                                 // timelock expiration). This explain we don't panic!
 586                                 // We should refactor OnchainTxHandler::block_connected to
 587                                 // only test equality on competing claims.
 588                                 return None;
 589                         }
 590                 }
 591         }
 592         pub(crate) fn merge_package(&mut self, mut merge_from: PackageTemplate) {
 593                 assert_eq!(self.height_original, merge_from.height_original);
 594                 if self.malleability == PackageMalleability::Untractable || merge_from.malleability == PackageMalleability::Untractable {
 595                         panic!("Merging template on untractable packages");
 596                 }
 597                 if !self.aggregable || !merge_from.aggregable {
 598                         panic!("Merging non aggregatable packages");
 599                 }
 600                 if let Some((_, lead_input)) = self.inputs.first() {
 601                         for (_, v) in merge_from.inputs.iter() {
 602                                 if !lead_input.is_compatible(v) { panic!("Merging outputs from differing types !"); }
 603                         }
 604                 } else { panic!("Merging template on an empty package"); }
 605                 for (k, v) in merge_from.inputs.drain(..) {
 606                         self.inputs.push((k, v));
 607                 }
 608                 //TODO: verify coverage and sanity?
 609                 if self.soonest_conf_deadline > merge_from.soonest_conf_deadline {
 610                         self.soonest_conf_deadline = merge_from.soonest_conf_deadline;
 611                 }
 612                 if self.feerate_previous > merge_from.feerate_previous {
 613                         self.feerate_previous = merge_from.feerate_previous;
 614                 }
 615                 self.height_timer = cmp::min(self.height_timer, merge_from.height_timer);
 616         }
 617         /// Gets the amount of all outptus being spent by this package, only valid for malleable
 618         /// packages.
 619         pub(crate) fn package_amount(&self) -> u64 {
 620                 let mut amounts = 0;
 621                 for (_, outp) in self.inputs.iter() {
 622                         amounts += outp.amount();
 623                 }
 624                 amounts
 625         }
 626         pub(crate) fn package_timelock(&self) -> u32 {
 627                 self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(self.height_original))
 628                         .max().expect("There must always be at least one output to spend in a PackageTemplate")
 629         }
 630         pub(crate) fn package_weight(&self, destination_script: &Script) -> usize {
 631                 let mut inputs_weight = 0;
 632                 let mut witnesses_weight = 2; // count segwit flags
 633                 for (_, outp) in self.inputs.iter() {
 634                         // previous_out_point: 36 bytes ; var_int: 1 byte ; sequence: 4 bytes
 635                         inputs_weight += 41 * WITNESS_SCALE_FACTOR;
 636                         witnesses_weight += outp.weight();
 637                 }
 638                 // version: 4 bytes ; count_tx_in: 1 byte ; count_tx_out: 1 byte ; lock_time: 4 bytes
 639                 let transaction_weight = 10 * WITNESS_SCALE_FACTOR;
 640                 // value: 8 bytes ; var_int: 1 byte ; pk_script: `destination_script.len()`
 641                 let output_weight = (8 + 1 + destination_script.len()) * WITNESS_SCALE_FACTOR;
 642                 inputs_weight + witnesses_weight + transaction_weight + output_weight
 643         }
 644         pub(crate) fn finalize_malleable_package<L: Deref, Signer: Sign>(
 645                 &self, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64, destination_script: Script, logger: &L
 646         ) -> Option<Transaction> where L::Target: Logger {
 647                 debug_assert!(self.is_malleable());
 648                 let mut bumped_tx = Transaction {
 649                         version: 2,
 650                         lock_time: PackedLockTime::ZERO,
 651                         input: vec![],
 652                         output: vec![TxOut {
 653                                 script_pubkey: destination_script,
 654                                 value,
 655                         }],
 656                 };
 657                 for (outpoint, _) in self.inputs.iter() {
 658                         bumped_tx.input.push(TxIn {
 659                                 previous_output: *outpoint,
 660                                 script_sig: Script::new(),
 661                                 sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
 662                                 witness: Witness::new(),
 663                         });
 664                 }
 665                 for (i, (outpoint, out)) in self.inputs.iter().enumerate() {
 666                         log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 667                         if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { return None; }
 668                 }
 669                 log_debug!(logger, "Finalized transaction {} ready to broadcast", bumped_tx.txid());
 670                 Some(bumped_tx)
 671         }
 672         pub(crate) fn finalize_untractable_package<L: Deref, Signer: Sign>(
 673                 &self, onchain_handler: &mut OnchainTxHandler<Signer>, logger: &L,
 674         ) -> Option<Transaction> where L::Target: Logger {
 675                 debug_assert!(!self.is_malleable());
 676                 if let Some((outpoint, outp)) = self.inputs.first() {
 677                         if let Some(final_tx) = outp.get_finalized_tx(outpoint, onchain_handler) {
 678                                 log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 679                                 log_debug!(logger, "Finalized transaction {} ready to broadcast", final_tx.txid());
 680                                 return Some(final_tx);
 681                         }
 682                         return None;
 683                 } else { panic!("API Error: Package must not be inputs empty"); }
 684         }
 685         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 686         /// 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
 687         /// height that once reached we should generate a new bumped "version" of the claim tx to be sure that we safely claim outputs before
 688         /// that our counterparty can do so. If timelock expires soon, height timer is going to be scaled down in consequence to increase
 689         /// frequency of the bump and so increase our bets of success.
 690         pub(crate) fn get_height_timer(&self, current_height: u32) -> u32 {
 691                 if self.soonest_conf_deadline <= current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL {
 692                         return current_height + HIGH_FREQUENCY_BUMP_INTERVAL
 693                 } else if self.soonest_conf_deadline - current_height <= LOW_FREQUENCY_BUMP_INTERVAL {
 694                         return current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL
 695                 }
 696                 current_height + LOW_FREQUENCY_BUMP_INTERVAL
 697         }
 698
 699         /// Returns value in satoshis to be included as package outgoing output amount and feerate
 700         /// which was used to generate the value. Will not return less than `dust_limit_sats` for the
 701         /// value.
 702         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)>
 703                 where F::Target: FeeEstimator,
 704                       L::Target: Logger,
 705         {
 706                 debug_assert!(self.malleability == PackageMalleability::Malleable, "The package output is fixed for non-malleable packages");
 707                 let input_amounts = self.package_amount();
 708                 assert!(dust_limit_sats as i64 > 0, "Output script must be broadcastable/have a 'real' dust limit.");
 709                 // If old feerate is 0, first iteration of this claim, use normal fee calculation
 710                 if self.feerate_previous != 0 {
 711                         if let Some((new_fee, feerate)) = feerate_bump(predicted_weight, input_amounts, self.feerate_previous, fee_estimator, logger) {
 712                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 713                         }
 714                 } else {
 715                         if let Some((new_fee, feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 716                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 717                         }
 718                 }
 719                 None
 720         }
 721
 722         #[cfg(anchors)]
 723         /// Computes a feerate based on the given confirmation target. If a previous feerate was used,
 724         /// and the new feerate is below it, we'll use a 25% increase of the previous feerate instead of
 725         /// the new one.
 726         pub(crate) fn compute_package_feerate<F: Deref>(
 727                 &self, fee_estimator: &LowerBoundedFeeEstimator<F>, conf_target: ConfirmationTarget,
 728         ) -> u32 where F::Target: FeeEstimator {
 729                 let feerate_estimate = fee_estimator.bounded_sat_per_1000_weight(conf_target);
 730                 if self.feerate_previous != 0 {
 731                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 732                         if feerate_estimate as u64 > self.feerate_previous {
 733                                 feerate_estimate
 734                         } else {
 735                                 // ...else just increase the previous feerate by 25% (because that's a nice number)
 736                                 (self.feerate_previous + (self.feerate_previous / 4)).try_into().unwrap_or(u32::max_value())
 737                         }
 738                 } else {
 739                         feerate_estimate
 740                 }
 741         }
 742
 743         /// Determines whether a package contains an input which must have additional external inputs
 744         /// attached to help the spending transaction reach confirmation.
 745         pub(crate) fn requires_external_funding(&self) -> bool {
 746                 self.inputs.iter().find(|input| match input.1 {
 747                         PackageSolvingData::HolderFundingOutput(ref outp) => outp.opt_anchors(),
 748                         _ => false,
 749                 }).is_some()
 750         }
 751
 752         pub (crate) fn build_package(txid: Txid, vout: u32, input_solving_data: PackageSolvingData, soonest_conf_deadline: u32, aggregable: bool, height_original: u32) -> Self {
 753                 let malleability = match input_solving_data {
 754                         PackageSolvingData::RevokedOutput(..) => PackageMalleability::Malleable,
 755                         PackageSolvingData::RevokedHTLCOutput(..) => PackageMalleability::Malleable,
 756                         PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => PackageMalleability::Malleable,
 757                         PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => PackageMalleability::Malleable,
 758                         PackageSolvingData::HolderHTLCOutput(..) => PackageMalleability::Untractable,
 759                         PackageSolvingData::HolderFundingOutput(..) => PackageMalleability::Untractable,
 760                 };
 761                 let mut inputs = Vec::with_capacity(1);
 762                 inputs.push((BitcoinOutPoint { txid, vout }, input_solving_data));
 763                 PackageTemplate {
 764                         inputs,
 765                         malleability,
 766                         soonest_conf_deadline,
 767                         aggregable,
 768                         feerate_previous: 0,
 769                         height_timer: None,
 770                         height_original,
 771                 }
 772         }
 773 }
 774
 775 impl Writeable for PackageTemplate {
 776         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 777                 writer.write_all(&byte_utils::be64_to_array(self.inputs.len() as u64))?;
 778                 for (ref outpoint, ref rev_outp) in self.inputs.iter() {
 779                         outpoint.write(writer)?;
 780                         rev_outp.write(writer)?;
 781                 }
 782                 write_tlv_fields!(writer, {
 783                         (0, self.soonest_conf_deadline, required),
 784                         (2, self.feerate_previous, required),
 785                         (4, self.height_original, required),
 786                         (6, self.height_timer, option)
 787                 });
 788                 Ok(())
 789         }
 790 }
 791
 792 impl Readable for PackageTemplate {
 793         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 794                 let inputs_count = <u64 as Readable>::read(reader)?;
 795                 let mut inputs: Vec<(BitcoinOutPoint, PackageSolvingData)> = Vec::with_capacity(cmp::min(inputs_count as usize, MAX_ALLOC_SIZE / 128));
 796                 for _ in 0..inputs_count {
 797                         let outpoint = Readable::read(reader)?;
 798                         let rev_outp = Readable::read(reader)?;
 799                         inputs.push((outpoint, rev_outp));
 800                 }
 801                 let (malleability, aggregable) = if let Some((_, lead_input)) = inputs.first() {
 802                         match lead_input {
 803                                 PackageSolvingData::RevokedOutput(..) => { (PackageMalleability::Malleable, true) },
 804                                 PackageSolvingData::RevokedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 805                                 PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 806                                 PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { (PackageMalleability::Malleable, false) },
 807                                 PackageSolvingData::HolderHTLCOutput(..) => { (PackageMalleability::Untractable, false) },
 808                                 PackageSolvingData::HolderFundingOutput(..) => { (PackageMalleability::Untractable, false) },
 809                         }
 810                 } else { return Err(DecodeError::InvalidValue); };
 811                 let mut soonest_conf_deadline = 0;
 812                 let mut feerate_previous = 0;
 813                 let mut height_timer = None;
 814                 let mut height_original = 0;
 815                 read_tlv_fields!(reader, {
 816                         (0, soonest_conf_deadline, required),
 817                         (2, feerate_previous, required),
 818                         (4, height_original, required),
 819                         (6, height_timer, option),
 820                 });
 821                 Ok(PackageTemplate {
 822                         inputs,
 823                         malleability,
 824                         soonest_conf_deadline,
 825                         aggregable,
 826                         feerate_previous,
 827                         height_timer,
 828                         height_original,
 829                 })
 830         }
 831 }
 832
 833 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 834 /// weight. We start with the highest priority feerate returned by the node's fee estimator then
 835 /// fall-back to lower priorities until we have enough value available to suck from.
 836 ///
 837 /// If the proposed fee is less than the available spent output's values, we return the proposed
 838 /// fee and the corresponding updated feerate. If the proposed fee is equal or more than the
 839 /// available spent output's values, we return nothing
 840 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)>
 841         where F::Target: FeeEstimator,
 842               L::Target: Logger,
 843 {
 844         let mut updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64;
 845         let mut fee = updated_feerate * (predicted_weight as u64) / 1000;
 846         if input_amounts <= fee {
 847                 updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal) as u64;
 848                 fee = updated_feerate * (predicted_weight as u64) / 1000;
 849                 if input_amounts <= fee {
 850                         updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background) as u64;
 851                         fee = updated_feerate * (predicted_weight as u64) / 1000;
 852                         if input_amounts <= fee {
 853                                 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)",
 854                                         fee, input_amounts);
 855                                 None
 856                         } else {
 857                                 log_warn!(logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 858                                         input_amounts);
 859                                 Some((fee, updated_feerate))
 860                         }
 861                 } else {
 862                         log_warn!(logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 863                                 input_amounts);
 864                         Some((fee, updated_feerate))
 865                 }
 866         } else {
 867                 Some((fee, updated_feerate))
 868         }
 869 }
 870
 871 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 872 /// weight. If feerates proposed by the fee-estimator have been increasing since last fee-bumping
 873 /// attempt, use them. Otherwise, blindly bump the feerate by 25% of the previous feerate. We also
 874 /// verify that those bumping heuristics respect BIP125 rules 3) and 4) and if required adjust
 875 /// the new fee to meet the RBF policy requirement.
 876 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)>
 877         where F::Target: FeeEstimator,
 878               L::Target: Logger,
 879 {
 880         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 881         let new_fee = if let Some((new_fee, _)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 882                 let updated_feerate = new_fee / (predicted_weight as u64 * 1000);
 883                 if updated_feerate > previous_feerate {
 884                         new_fee
 885                 } else {
 886                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 887                         let new_fee = previous_feerate * (predicted_weight as u64) / 750;
 888                         if input_amounts <= new_fee {
 889                                 log_warn!(logger, "Can't 25% bump new claiming tx, amount {} is too small", input_amounts);
 890                                 return None;
 891                         }
 892                         new_fee
 893                 }
 894         } else {
 895                 log_warn!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", input_amounts);
 896                 return None;
 897         };
 898
 899         let previous_fee = previous_feerate * (predicted_weight as u64) / 1000;
 900         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * (predicted_weight as u64) / 1000;
 901         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 902         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 903         //      * 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.
 904         let new_fee = if new_fee < previous_fee + min_relay_fee {
 905                 new_fee + previous_fee + min_relay_fee - new_fee
 906         } else {
 907                 new_fee
 908         };
 909         Some((new_fee, new_fee * 1000 / (predicted_weight as u64)))
 910 }
 911
 912 #[cfg(test)]
 913 mod tests {
 914         use crate::chain::package::{CounterpartyOfferedHTLCOutput, CounterpartyReceivedHTLCOutput, HolderHTLCOutput, PackageTemplate, PackageSolvingData, RevokedOutput, WEIGHT_REVOKED_OUTPUT, weight_offered_htlc, weight_received_htlc};
 915         use crate::chain::Txid;
 916         use crate::ln::chan_utils::HTLCOutputInCommitment;
 917         use crate::ln::{PaymentPreimage, PaymentHash};
 918
 919         use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
 920         use bitcoin::blockdata::script::Script;
 921         use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
 922
 923         use bitcoin::hashes::hex::FromHex;
 924
 925         use bitcoin::secp256k1::{PublicKey,SecretKey};
 926         use bitcoin::secp256k1::Secp256k1;
 927
 928         macro_rules! dumb_revk_output {
 929                 ($secp_ctx: expr) => {
 930                         {
 931                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 932                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 933                                 PackageSolvingData::RevokedOutput(RevokedOutput::build(dumb_point, dumb_point, dumb_point, dumb_scalar, 0, 0))
 934                         }
 935                 }
 936         }
 937
 938         macro_rules! dumb_counterparty_output {
 939                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
 940                         {
 941                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 942                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 943                                 let hash = PaymentHash([1; 32]);
 944                                 let htlc = HTLCOutputInCommitment { offered: true, amount_msat: $amt, cltv_expiry: 0, payment_hash: hash, transaction_output_index: None };
 945                                 PackageSolvingData::CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput::build(dumb_point, dumb_point, dumb_point, htlc, $opt_anchors))
 946                         }
 947                 }
 948         }
 949
 950         macro_rules! dumb_counterparty_offered_output {
 951                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
 952                         {
 953                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 954                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
 955                                 let hash = PaymentHash([1; 32]);
 956                                 let preimage = PaymentPreimage([2;32]);
 957                                 let htlc = HTLCOutputInCommitment { offered: false, amount_msat: $amt, cltv_expiry: 1000, payment_hash: hash, transaction_output_index: None };
 958                                 PackageSolvingData::CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput::build(dumb_point, dumb_point, dumb_point, preimage, htlc, $opt_anchors))
 959                         }
 960                 }
 961         }
 962
 963         macro_rules! dumb_htlc_output {
 964                 () => {
 965                         {
 966                                 let preimage = PaymentPreimage([2;32]);
 967                                 PackageSolvingData::HolderHTLCOutput(HolderHTLCOutput::build_accepted(preimage, 0))
 968                         }
 969                 }
 970         }
 971
 972         #[test]
 973         #[should_panic]
 974         fn test_package_differing_heights() {
 975                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
 976                 let secp_ctx = Secp256k1::new();
 977                 let revk_outp = dumb_revk_output!(secp_ctx);
 978
 979                 let mut package_one_hundred = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
 980                 let package_two_hundred = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 200);
 981                 package_one_hundred.merge_package(package_two_hundred);
 982         }
 983
 984         #[test]
 985         #[should_panic]
 986         fn test_package_untractable_merge_to() {
 987                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
 988                 let secp_ctx = Secp256k1::new();
 989                 let revk_outp = dumb_revk_output!(secp_ctx);
 990                 let htlc_outp = dumb_htlc_output!();
 991
 992                 let mut untractable_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
 993                 let malleable_package = PackageTemplate::build_package(txid, 1, htlc_outp.clone(), 1000, true, 100);
 994                 untractable_package.merge_package(malleable_package);
 995         }
 996
 997         #[test]
 998         #[should_panic]
 999         fn test_package_untractable_merge_from() {
1000                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1001                 let secp_ctx = Secp256k1::new();
1002                 let htlc_outp = dumb_htlc_output!();
1003                 let revk_outp = dumb_revk_output!(secp_ctx);
1004
1005                 let mut malleable_package = PackageTemplate::build_package(txid, 0, htlc_outp.clone(), 1000, true, 100);
1006                 let untractable_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1007                 malleable_package.merge_package(untractable_package);
1008         }
1009
1010         #[test]
1011         #[should_panic]
1012         fn test_package_noaggregation_to() {
1013                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1014                 let secp_ctx = Secp256k1::new();
1015                 let revk_outp = dumb_revk_output!(secp_ctx);
1016
1017                 let mut noaggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, false, 100);
1018                 let aggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1019                 noaggregation_package.merge_package(aggregation_package);
1020         }
1021
1022         #[test]
1023         #[should_panic]
1024         fn test_package_noaggregation_from() {
1025                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1026                 let secp_ctx = Secp256k1::new();
1027                 let revk_outp = dumb_revk_output!(secp_ctx);
1028
1029                 let mut aggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1030                 let noaggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, false, 100);
1031                 aggregation_package.merge_package(noaggregation_package);
1032         }
1033
1034         #[test]
1035         #[should_panic]
1036         fn test_package_empty() {
1037                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1038                 let secp_ctx = Secp256k1::new();
1039                 let revk_outp = dumb_revk_output!(secp_ctx);
1040
1041                 let mut empty_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1042                 empty_package.inputs = vec![];
1043                 let package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1044                 empty_package.merge_package(package);
1045         }
1046
1047         #[test]
1048         #[should_panic]
1049         fn test_package_differing_categories() {
1050                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1051                 let secp_ctx = Secp256k1::new();
1052                 let revk_outp = dumb_revk_output!(secp_ctx);
1053                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 0, false);
1054
1055                 let mut revoked_package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1056                 let counterparty_package = PackageTemplate::build_package(txid, 1, counterparty_outp, 1000, true, 100);
1057                 revoked_package.merge_package(counterparty_package);
1058         }
1059
1060         #[test]
1061         fn test_package_split_malleable() {
1062                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1063                 let secp_ctx = Secp256k1::new();
1064                 let revk_outp_one = dumb_revk_output!(secp_ctx);
1065                 let revk_outp_two = dumb_revk_output!(secp_ctx);
1066                 let revk_outp_three = dumb_revk_output!(secp_ctx);
1067
1068                 let mut package_one = PackageTemplate::build_package(txid, 0, revk_outp_one, 1000, true, 100);
1069                 let package_two = PackageTemplate::build_package(txid, 1, revk_outp_two, 1000, true, 100);
1070                 let package_three = PackageTemplate::build_package(txid, 2, revk_outp_three, 1000, true, 100);
1071
1072                 package_one.merge_package(package_two);
1073                 package_one.merge_package(package_three);
1074                 assert_eq!(package_one.outpoints().len(), 3);
1075
1076                 if let Some(split_package) = package_one.split_package(&BitcoinOutPoint { txid, vout: 1 }) {
1077                         // Packages attributes should be identical
1078                         assert!(split_package.is_malleable());
1079                         assert_eq!(split_package.soonest_conf_deadline, package_one.soonest_conf_deadline);
1080                         assert_eq!(split_package.aggregable, package_one.aggregable);
1081                         assert_eq!(split_package.feerate_previous, package_one.feerate_previous);
1082                         assert_eq!(split_package.height_timer, package_one.height_timer);
1083                         assert_eq!(split_package.height_original, package_one.height_original);
1084                 } else { panic!(); }
1085                 assert_eq!(package_one.outpoints().len(), 2);
1086         }
1087
1088         #[test]
1089         fn test_package_split_untractable() {
1090                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1091                 let htlc_outp_one = dumb_htlc_output!();
1092
1093                 let mut package_one = PackageTemplate::build_package(txid, 0, htlc_outp_one, 1000, true, 100);
1094                 let ret_split = package_one.split_package(&BitcoinOutPoint { txid, vout: 0});
1095                 assert!(ret_split.is_none());
1096         }
1097
1098         #[test]
1099         fn test_package_timer() {
1100                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1101                 let secp_ctx = Secp256k1::new();
1102                 let revk_outp = dumb_revk_output!(secp_ctx);
1103
1104                 let mut package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1105                 let timer_none = package.timer();
1106                 assert!(timer_none.is_none());
1107                 package.set_timer(Some(100));
1108                 if let Some(timer_some) = package.timer() {
1109                         assert_eq!(timer_some, 100);
1110                 } else { panic!() }
1111         }
1112
1113         #[test]
1114         fn test_package_amounts() {
1115                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1116                 let secp_ctx = Secp256k1::new();
1117                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, false);
1118
1119                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1120                 assert_eq!(package.package_amount(), 1000);
1121         }
1122
1123         #[test]
1124         fn test_package_weight() {
1125                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1126                 let secp_ctx = Secp256k1::new();
1127
1128                 // (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)
1129                 let weight_sans_output = (4 + 4 + 1 + 36 + 4 + 1 + 1 + 8 + 1) * WITNESS_SCALE_FACTOR + 2;
1130
1131                 {
1132                         let revk_outp = dumb_revk_output!(secp_ctx);
1133                         let package = PackageTemplate::build_package(txid, 0, revk_outp, 0, true, 100);
1134                         assert_eq!(package.package_weight(&Script::new()),  weight_sans_output + WEIGHT_REVOKED_OUTPUT as usize);
1135                 }
1136
1137                 {
1138                         for &opt_anchors in [false, true].iter() {
1139                                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, opt_anchors);
1140                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1141                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_received_htlc(opt_anchors) as usize);
1142                         }
1143                 }
1144
1145                 {
1146                         for &opt_anchors in [false, true].iter() {
1147                                 let counterparty_outp = dumb_counterparty_offered_output!(secp_ctx, 1_000_000, opt_anchors);
1148                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1149                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_offered_htlc(opt_anchors) as usize);
1150                         }
1151                 }
1152         }
1153 }