_ 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::sign::WriteableEcdsaChannelSigner;
  29 #[cfg(anchors)]
  30 use crate::chain::onchaintx::ExternalHTLCClaim;
  31 use crate::chain::onchaintx::OnchainTxHandler;
  32 use crate::util::logger::Logger;
  33 use crate::util::ser::{Readable, Writer, Writeable};
  34
  35 use crate::io;
  36 use crate::prelude::*;
  37 use core::cmp;
  38 #[cfg(anchors)]
  39 use core::convert::TryInto;
  40 use core::mem;
  41 use core::ops::Deref;
  42 use bitcoin::{PackedLockTime, Sequence, Witness};
  43
  44 use super::chaininterface::LowerBoundedFeeEstimator;
  45
  46 const MAX_ALLOC_SIZE: usize = 64*1024;
  47
  48
  49 pub(crate) fn weight_revoked_offered_htlc(opt_anchors: bool) -> u64 {
  50         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  51         const WEIGHT_REVOKED_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 + 133;
  52         const WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  53         if opt_anchors { WEIGHT_REVOKED_OFFERED_HTLC_ANCHORS } else { WEIGHT_REVOKED_OFFERED_HTLC }
  54 }
  55
  56 pub(crate) fn weight_revoked_received_htlc(opt_anchors: bool) -> u64 {
  57         // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
  58         const WEIGHT_REVOKED_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 33 + 1 +  139;
  59         const WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_REVOKED_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  60         if opt_anchors { WEIGHT_REVOKED_RECEIVED_HTLC_ANCHORS } else { WEIGHT_REVOKED_RECEIVED_HTLC }
  61 }
  62
  63 pub(crate) fn weight_offered_htlc(opt_anchors: bool) -> u64 {
  64         // number_of_witness_elements + sig_length + counterpartyhtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
  65         const WEIGHT_OFFERED_HTLC: u64 = 1 + 1 + 73 + 1 + 32 + 1 + 133;
  66         const WEIGHT_OFFERED_HTLC_ANCHORS: u64 = WEIGHT_OFFERED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  67         if opt_anchors { WEIGHT_OFFERED_HTLC_ANCHORS } else { WEIGHT_OFFERED_HTLC }
  68 }
  69
  70 pub(crate) fn weight_received_htlc(opt_anchors: bool) -> u64 {
  71         // number_of_witness_elements + sig_length + counterpartyhtlc_sig + empty_vec_length + empty_vec + witness_script_length + witness_script
  72         const WEIGHT_RECEIVED_HTLC: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 139;
  73         const WEIGHT_RECEIVED_HTLC_ANCHORS: u64 = WEIGHT_RECEIVED_HTLC + 3; // + OP_1 + OP_CSV + OP_DROP
  74         if opt_anchors { WEIGHT_RECEIVED_HTLC_ANCHORS } else { WEIGHT_RECEIVED_HTLC }
  75 }
  76
  77 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
  78 pub(crate) const WEIGHT_REVOKED_OUTPUT: u64 = 1 + 1 + 73 + 1 + 1 + 1 + 77;
  79
  80 /// Height delay at which transactions are fee-bumped/rebroadcasted with a low priority.
  81 const LOW_FREQUENCY_BUMP_INTERVAL: u32 = 15;
  82 /// Height delay at which transactions are fee-bumped/rebroadcasted with a middle priority.
  83 const MIDDLE_FREQUENCY_BUMP_INTERVAL: u32 = 3;
  84 /// Height delay at which transactions are fee-bumped/rebroadcasted with a high priority.
  85 const HIGH_FREQUENCY_BUMP_INTERVAL: u32 = 1;
  86
  87 /// A struct to describe a revoked output and corresponding information to generate a solving
  88 /// witness spending a commitment `to_local` output or a second-stage HTLC transaction output.
  89 ///
  90 /// CSV and pubkeys are used as part of a witnessScript redeeming a balance output, amount is used
  91 /// as part of the signature hash and revocation secret to generate a satisfying witness.
  92 #[derive(Clone, PartialEq, Eq)]
  93 pub(crate) struct RevokedOutput {
  94         per_commitment_point: PublicKey,
  95         counterparty_delayed_payment_base_key: PublicKey,
  96         counterparty_htlc_base_key: PublicKey,
  97         per_commitment_key: SecretKey,
  98         weight: u64,
  99         amount: u64,
 100         on_counterparty_tx_csv: u16,
 101         is_counterparty_balance_on_anchors: Option<()>,
 102 }
 103
 104 impl RevokedOutput {
 105         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, is_counterparty_balance_on_anchors: bool) -> Self {
 106                 RevokedOutput {
 107                         per_commitment_point,
 108                         counterparty_delayed_payment_base_key,
 109                         counterparty_htlc_base_key,
 110                         per_commitment_key,
 111                         weight: WEIGHT_REVOKED_OUTPUT,
 112                         amount,
 113                         on_counterparty_tx_csv,
 114                         is_counterparty_balance_on_anchors: if is_counterparty_balance_on_anchors { Some(()) } else { None }
 115                 }
 116         }
 117 }
 118
 119 impl_writeable_tlv_based!(RevokedOutput, {
 120         (0, per_commitment_point, required),
 121         (2, counterparty_delayed_payment_base_key, required),
 122         (4, counterparty_htlc_base_key, required),
 123         (6, per_commitment_key, required),
 124         (8, weight, required),
 125         (10, amount, required),
 126         (12, on_counterparty_tx_csv, required),
 127         (14, is_counterparty_balance_on_anchors, option)
 128 });
 129
 130 /// A struct to describe a revoked offered output and corresponding information to generate a
 131 /// solving witness.
 132 ///
 133 /// HTLCOuputInCommitment (hash timelock, direction) and pubkeys are used to generate a suitable
 134 /// witnessScript.
 135 ///
 136 /// CSV is used as part of a witnessScript redeeming a balance output, amount is used as part
 137 /// of the signature hash and revocation secret to generate a satisfying witness.
 138 #[derive(Clone, PartialEq, Eq)]
 139 pub(crate) struct RevokedHTLCOutput {
 140         per_commitment_point: PublicKey,
 141         counterparty_delayed_payment_base_key: PublicKey,
 142         counterparty_htlc_base_key: PublicKey,
 143         per_commitment_key: SecretKey,
 144         weight: u64,
 145         amount: u64,
 146         htlc: HTLCOutputInCommitment,
 147 }
 148
 149 impl RevokedHTLCOutput {
 150         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 {
 151                 let weight = if htlc.offered { weight_revoked_offered_htlc(opt_anchors) } else { weight_revoked_received_htlc(opt_anchors) };
 152                 RevokedHTLCOutput {
 153                         per_commitment_point,
 154                         counterparty_delayed_payment_base_key,
 155                         counterparty_htlc_base_key,
 156                         per_commitment_key,
 157                         weight,
 158                         amount,
 159                         htlc
 160                 }
 161         }
 162 }
 163
 164 impl_writeable_tlv_based!(RevokedHTLCOutput, {
 165         (0, per_commitment_point, required),
 166         (2, counterparty_delayed_payment_base_key, required),
 167         (4, counterparty_htlc_base_key, required),
 168         (6, per_commitment_key, required),
 169         (8, weight, required),
 170         (10, amount, required),
 171         (12, htlc, required),
 172 });
 173
 174 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 175 ///
 176 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 177 /// witnessScript.
 178 ///
 179 /// The preimage is used as part of the witness.
 180 #[derive(Clone, PartialEq, Eq)]
 181 pub(crate) struct CounterpartyOfferedHTLCOutput {
 182         per_commitment_point: PublicKey,
 183         counterparty_delayed_payment_base_key: PublicKey,
 184         counterparty_htlc_base_key: PublicKey,
 185         preimage: PaymentPreimage,
 186         htlc: HTLCOutputInCommitment,
 187         opt_anchors: Option<()>,
 188 }
 189
 190 impl CounterpartyOfferedHTLCOutput {
 191         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 {
 192                 CounterpartyOfferedHTLCOutput {
 193                         per_commitment_point,
 194                         counterparty_delayed_payment_base_key,
 195                         counterparty_htlc_base_key,
 196                         preimage,
 197                         htlc,
 198                         opt_anchors: if opt_anchors { Some(()) } else { None },
 199                 }
 200         }
 201
 202         fn opt_anchors(&self) -> bool {
 203                 self.opt_anchors.is_some()
 204         }
 205 }
 206
 207 impl_writeable_tlv_based!(CounterpartyOfferedHTLCOutput, {
 208         (0, per_commitment_point, required),
 209         (2, counterparty_delayed_payment_base_key, required),
 210         (4, counterparty_htlc_base_key, required),
 211         (6, preimage, required),
 212         (8, htlc, required),
 213         (10, opt_anchors, option),
 214 });
 215
 216 /// A struct to describe a HTLC output on a counterparty commitment transaction.
 217 ///
 218 /// HTLCOutputInCommitment (hash, timelock, directon) and pubkeys are used to generate a suitable
 219 /// witnessScript.
 220 #[derive(Clone, PartialEq, Eq)]
 221 pub(crate) struct CounterpartyReceivedHTLCOutput {
 222         per_commitment_point: PublicKey,
 223         counterparty_delayed_payment_base_key: PublicKey,
 224         counterparty_htlc_base_key: PublicKey,
 225         htlc: HTLCOutputInCommitment,
 226         opt_anchors: Option<()>,
 227 }
 228
 229 impl CounterpartyReceivedHTLCOutput {
 230         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 {
 231                 CounterpartyReceivedHTLCOutput {
 232                         per_commitment_point,
 233                         counterparty_delayed_payment_base_key,
 234                         counterparty_htlc_base_key,
 235                         htlc,
 236                         opt_anchors: if opt_anchors { Some(()) } else { None },
 237                 }
 238         }
 239
 240         fn opt_anchors(&self) -> bool {
 241                 self.opt_anchors.is_some()
 242         }
 243 }
 244
 245 impl_writeable_tlv_based!(CounterpartyReceivedHTLCOutput, {
 246         (0, per_commitment_point, required),
 247         (2, counterparty_delayed_payment_base_key, required),
 248         (4, counterparty_htlc_base_key, required),
 249         (6, htlc, required),
 250         (8, opt_anchors, option),
 251 });
 252
 253 /// A struct to describe a HTLC output on holder commitment transaction.
 254 ///
 255 /// Either offered or received, the amount is always used as part of the bip143 sighash.
 256 /// Preimage is only included as part of the witness in former case.
 257 #[derive(Clone, PartialEq, Eq)]
 258 pub(crate) struct HolderHTLCOutput {
 259         preimage: Option<PaymentPreimage>,
 260         amount_msat: u64,
 261         /// Defaults to 0 for HTLC-Success transactions, which have no expiry
 262         cltv_expiry: u32,
 263         opt_anchors: Option<()>,
 264 }
 265
 266 impl HolderHTLCOutput {
 267         pub(crate) fn build_offered(amount_msat: u64, cltv_expiry: u32, opt_anchors: bool) -> Self {
 268                 HolderHTLCOutput {
 269                         preimage: None,
 270                         amount_msat,
 271                         cltv_expiry,
 272                         opt_anchors: if opt_anchors { Some(()) } else { None } ,
 273                 }
 274         }
 275
 276         pub(crate) fn build_accepted(preimage: PaymentPreimage, amount_msat: u64, opt_anchors: bool) -> Self {
 277                 HolderHTLCOutput {
 278                         preimage: Some(preimage),
 279                         amount_msat,
 280                         cltv_expiry: 0,
 281                         opt_anchors: if opt_anchors { Some(()) } else { None } ,
 282                 }
 283         }
 284
 285         fn opt_anchors(&self) -> bool {
 286                 self.opt_anchors.is_some()
 287         }
 288 }
 289
 290 impl_writeable_tlv_based!(HolderHTLCOutput, {
 291         (0, amount_msat, required),
 292         (2, cltv_expiry, required),
 293         (4, preimage, option),
 294         (6, opt_anchors, option)
 295 });
 296
 297 /// A struct to describe the channel output on the funding transaction.
 298 ///
 299 /// witnessScript is used as part of the witness redeeming the funding utxo.
 300 #[derive(Clone, PartialEq, Eq)]
 301 pub(crate) struct HolderFundingOutput {
 302         funding_redeemscript: Script,
 303         funding_amount: Option<u64>,
 304         opt_anchors: Option<()>,
 305 }
 306
 307
 308 impl HolderFundingOutput {
 309         pub(crate) fn build(funding_redeemscript: Script, funding_amount: u64, opt_anchors: bool) -> Self {
 310                 HolderFundingOutput {
 311                         funding_redeemscript,
 312                         funding_amount: Some(funding_amount),
 313                         opt_anchors: if opt_anchors { Some(()) } else { None },
 314                 }
 315         }
 316
 317         fn opt_anchors(&self) -> bool {
 318                 self.opt_anchors.is_some()
 319         }
 320 }
 321
 322 impl_writeable_tlv_based!(HolderFundingOutput, {
 323         (0, funding_redeemscript, required),
 324         (2, opt_anchors, option),
 325         (3, funding_amount, option),
 326 });
 327
 328 /// A wrapper encapsulating all in-protocol differing outputs types.
 329 ///
 330 /// The generic API offers access to an outputs common attributes or allow transformation such as
 331 /// finalizing an input claiming the output.
 332 #[derive(Clone, PartialEq, Eq)]
 333 pub(crate) enum PackageSolvingData {
 334         RevokedOutput(RevokedOutput),
 335         RevokedHTLCOutput(RevokedHTLCOutput),
 336         CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput),
 337         CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput),
 338         HolderHTLCOutput(HolderHTLCOutput),
 339         HolderFundingOutput(HolderFundingOutput),
 340 }
 341
 342 impl PackageSolvingData {
 343         fn amount(&self) -> u64 {
 344                 let amt = match self {
 345                         PackageSolvingData::RevokedOutput(ref outp) => outp.amount,
 346                         PackageSolvingData::RevokedHTLCOutput(ref outp) => outp.amount,
 347                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 348                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => outp.htlc.amount_msat / 1000,
 349                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 350                                 debug_assert!(outp.opt_anchors());
 351                                 outp.amount_msat / 1000
 352                         },
 353                         PackageSolvingData::HolderFundingOutput(ref outp) => {
 354                                 debug_assert!(outp.opt_anchors());
 355                                 outp.funding_amount.unwrap()
 356                         }
 357                 };
 358                 amt
 359         }
 360         fn weight(&self) -> usize {
 361                 match self {
 362                         PackageSolvingData::RevokedOutput(ref outp) => outp.weight as usize,
 363                         PackageSolvingData::RevokedHTLCOutput(ref outp) => outp.weight as usize,
 364                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => weight_offered_htlc(outp.opt_anchors()) as usize,
 365                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => weight_received_htlc(outp.opt_anchors()) as usize,
 366                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 367                                 debug_assert!(outp.opt_anchors());
 368                                 if outp.preimage.is_none() {
 369                                         weight_offered_htlc(true) as usize
 370                                 } else {
 371                                         weight_received_htlc(true) as usize
 372                                 }
 373                         },
 374                         // Since HolderFundingOutput maps to an untractable package that is already signed, its
 375                         // weight can be determined from the transaction itself.
 376                         PackageSolvingData::HolderFundingOutput(..) => unreachable!(),
 377                 }
 378         }
 379         fn is_compatible(&self, input: &PackageSolvingData) -> bool {
 380                 match self {
 381                         PackageSolvingData::RevokedOutput(..) => {
 382                                 match input {
 383                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 384                                         PackageSolvingData::RevokedOutput(..) => { true },
 385                                         _ => { false }
 386                                 }
 387                         },
 388                         PackageSolvingData::RevokedHTLCOutput(..) => {
 389                                 match input {
 390                                         PackageSolvingData::RevokedOutput(..) => { true },
 391                                         PackageSolvingData::RevokedHTLCOutput(..) => { true },
 392                                         _ => { false }
 393                                 }
 394                         },
 395                         _ => { mem::discriminant(self) == mem::discriminant(&input) }
 396                 }
 397         }
 398         fn finalize_input<Signer: WriteableEcdsaChannelSigner>(&self, bumped_tx: &mut Transaction, i: usize, onchain_handler: &mut OnchainTxHandler<Signer>) -> bool {
 399                 match self {
 400                         PackageSolvingData::RevokedOutput(ref outp) => {
 401                                 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);
 402                                 let witness_script = chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, outp.on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key);
 403                                 //TODO: should we panic on signer failure ?
 404                                 if let Ok(sig) = onchain_handler.signer.sign_justice_revoked_output(&bumped_tx, i, outp.amount, &outp.per_commitment_key, &onchain_handler.secp_ctx) {
 405                                         let mut ser_sig = sig.serialize_der().to_vec();
 406                                         ser_sig.push(EcdsaSighashType::All as u8);
 407                                         bumped_tx.input[i].witness.push(ser_sig);
 408                                         bumped_tx.input[i].witness.push(vec!(1));
 409                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 410                                 } else { return false; }
 411                         },
 412                         PackageSolvingData::RevokedHTLCOutput(ref outp) => {
 413                                 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);
 414                                 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);
 415                                 //TODO: should we panic on signer failure ?
 416                                 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) {
 417                                         let mut ser_sig = sig.serialize_der().to_vec();
 418                                         ser_sig.push(EcdsaSighashType::All as u8);
 419                                         bumped_tx.input[i].witness.push(ser_sig);
 420                                         bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
 421                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 422                                 } else { return false; }
 423                         },
 424                         PackageSolvingData::CounterpartyOfferedHTLCOutput(ref outp) => {
 425                                 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);
 426                                 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);
 427
 428                                 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) {
 429                                         let mut ser_sig = sig.serialize_der().to_vec();
 430                                         ser_sig.push(EcdsaSighashType::All as u8);
 431                                         bumped_tx.input[i].witness.push(ser_sig);
 432                                         bumped_tx.input[i].witness.push(outp.preimage.0.to_vec());
 433                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 434                                 }
 435                         },
 436                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => {
 437                                 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);
 438                                 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);
 439
 440                                 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) {
 441                                         let mut ser_sig = sig.serialize_der().to_vec();
 442                                         ser_sig.push(EcdsaSighashType::All as u8);
 443                                         bumped_tx.input[i].witness.push(ser_sig);
 444                                         // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
 445                                         bumped_tx.input[i].witness.push(vec![]);
 446                                         bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 447                                 }
 448                         },
 449                         _ => { panic!("API Error!"); }
 450                 }
 451                 true
 452         }
 453         fn get_finalized_tx<Signer: WriteableEcdsaChannelSigner>(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler<Signer>) -> Option<Transaction> {
 454                 match self {
 455                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 456                                 debug_assert!(!outp.opt_anchors());
 457                                 return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage);
 458                         }
 459                         PackageSolvingData::HolderFundingOutput(ref outp) => {
 460                                 return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript));
 461                         }
 462                         _ => { panic!("API Error!"); }
 463                 }
 464         }
 465         fn absolute_tx_timelock(&self, current_height: u32) -> u32 {
 466                 // We use `current_height` as our default locktime to discourage fee sniping and because
 467                 // transactions with it always propagate.
 468                 let absolute_timelock = match self {
 469                         PackageSolvingData::RevokedOutput(_) => current_height,
 470                         PackageSolvingData::RevokedHTLCOutput(_) => current_height,
 471                         PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => current_height,
 472                         PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, current_height),
 473                         // HTLC timeout/success transactions rely on a fixed timelock due to the counterparty's
 474                         // signature.
 475                         PackageSolvingData::HolderHTLCOutput(ref outp) => {
 476                                 if outp.preimage.is_some() {
 477                                         debug_assert_eq!(outp.cltv_expiry, 0);
 478                                 }
 479                                 outp.cltv_expiry
 480                         },
 481                         PackageSolvingData::HolderFundingOutput(_) => current_height,
 482                 };
 483                 absolute_timelock
 484         }
 485 }
 486
 487 impl_writeable_tlv_based_enum!(PackageSolvingData, ;
 488         (0, RevokedOutput),
 489         (1, RevokedHTLCOutput),
 490         (2, CounterpartyOfferedHTLCOutput),
 491         (3, CounterpartyReceivedHTLCOutput),
 492         (4, HolderHTLCOutput),
 493         (5, HolderFundingOutput),
 494 );
 495
 496 /// A malleable package might be aggregated with other packages to save on fees.
 497 /// A untractable package has been counter-signed and aggregable will break cached counterparty
 498 /// signatures.
 499 #[derive(Clone, PartialEq, Eq)]
 500 pub(crate) enum PackageMalleability {
 501         Malleable,
 502         Untractable,
 503 }
 504
 505 /// A structure to describe a package content that is generated by ChannelMonitor and
 506 /// used by OnchainTxHandler to generate and broadcast transactions settling onchain claims.
 507 ///
 508 /// A package is defined as one or more transactions claiming onchain outputs in reaction
 509 /// to confirmation of a channel transaction. Those packages might be aggregated to save on
 510 /// fees, if satisfaction of outputs's witnessScript let's us do so.
 511 ///
 512 /// As packages are time-sensitive, we fee-bump and rebroadcast them at scheduled intervals.
 513 /// Failing to confirm a package translate as a loss of funds for the user.
 514 #[derive(Clone, PartialEq, Eq)]
 515 pub struct PackageTemplate {
 516         // List of onchain outputs and solving data to generate satisfying witnesses.
 517         inputs: Vec<(BitcoinOutPoint, PackageSolvingData)>,
 518         // Packages are deemed as malleable if we have local knwoledge of at least one set of
 519         // private keys yielding a satisfying witnesses. Malleability implies that we can aggregate
 520         // packages among them to save on fees or rely on RBF to bump their feerates.
 521         // Untractable packages have been counter-signed and thus imply that we can't aggregate
 522         // them without breaking signatures. Fee-bumping strategy will also rely on CPFP.
 523         malleability: PackageMalleability,
 524         // Block height after which the earlier-output belonging to this package is mature for a
 525         // competing claim by the counterparty. As our chain tip becomes nearer from the timelock,
 526         // the fee-bumping frequency will increase. See `OnchainTxHandler::get_height_timer`.
 527         soonest_conf_deadline: u32,
 528         // Determines if this package can be aggregated.
 529         // Timelocked outputs belonging to the same transaction might have differing
 530         // satisfying heights. Picking up the later height among the output set would be a valid
 531         // aggregable strategy but it comes with at least 2 trade-offs :
 532         // * earlier-output fund are going to take longer to come back
 533         // * CLTV delta backing up a corresponding HTLC on an upstream channel could be swallowed
 534         // by the requirement of the later-output part of the set
 535         // For now, we mark such timelocked outputs as non-aggregable, though we might introduce
 536         // smarter aggregable strategy in the future.
 537         aggregable: bool,
 538         // Cache of package feerate committed at previous (re)broadcast. If bumping resources
 539         // (either claimed output value or external utxo), it will keep increasing until holder
 540         // or counterparty successful claim.
 541         feerate_previous: u64,
 542         // Cache of next height at which fee-bumping and rebroadcast will be attempted. In
 543         // the future, we might abstract it to an observed mempool fluctuation.
 544         height_timer: u32,
 545         // Confirmation height of the claimed outputs set transaction. In case of reorg reaching
 546         // it, we wipe out and forget the package.
 547         height_original: u32,
 548 }
 549
 550 impl PackageTemplate {
 551         pub(crate) fn is_malleable(&self) -> bool {
 552                 self.malleability == PackageMalleability::Malleable
 553         }
 554         pub(crate) fn timelock(&self) -> u32 {
 555                 self.soonest_conf_deadline
 556         }
 557         pub(crate) fn aggregable(&self) -> bool {
 558                 self.aggregable
 559         }
 560         pub(crate) fn previous_feerate(&self) -> u64 {
 561                 self.feerate_previous
 562         }
 563         pub(crate) fn set_feerate(&mut self, new_feerate: u64) {
 564                 self.feerate_previous = new_feerate;
 565         }
 566         pub(crate) fn timer(&self) -> u32 {
 567                 self.height_timer
 568         }
 569         pub(crate) fn set_timer(&mut self, new_timer: u32) {
 570                 self.height_timer = new_timer;
 571         }
 572         pub(crate) fn outpoints(&self) -> Vec<&BitcoinOutPoint> {
 573                 self.inputs.iter().map(|(o, _)| o).collect()
 574         }
 575         pub(crate) fn inputs(&self) -> impl ExactSizeIterator<Item = &PackageSolvingData> {
 576                 self.inputs.iter().map(|(_, i)| i)
 577         }
 578         pub(crate) fn split_package(&mut self, split_outp: &BitcoinOutPoint) -> Option<PackageTemplate> {
 579                 match self.malleability {
 580                         PackageMalleability::Malleable => {
 581                                 let mut split_package = None;
 582                                 let timelock = self.soonest_conf_deadline;
 583                                 let aggregable = self.aggregable;
 584                                 let feerate_previous = self.feerate_previous;
 585                                 let height_timer = self.height_timer;
 586                                 let height_original = self.height_original;
 587                                 self.inputs.retain(|outp| {
 588                                         if *split_outp == outp.0 {
 589                                                 split_package = Some(PackageTemplate {
 590                                                         inputs: vec![(outp.0, outp.1.clone())],
 591                                                         malleability: PackageMalleability::Malleable,
 592                                                         soonest_conf_deadline: timelock,
 593                                                         aggregable,
 594                                                         feerate_previous,
 595                                                         height_timer,
 596                                                         height_original,
 597                                                 });
 598                                                 return false;
 599                                         }
 600                                         return true;
 601                                 });
 602                                 return split_package;
 603                         },
 604                         _ => {
 605                                 // Note, we may try to split on remote transaction for
 606                                 // which we don't have a competing one (HTLC-Success before
 607                                 // timelock expiration). This explain we don't panic!
 608                                 // We should refactor OnchainTxHandler::block_connected to
 609                                 // only test equality on competing claims.
 610                                 return None;
 611                         }
 612                 }
 613         }
 614         pub(crate) fn merge_package(&mut self, mut merge_from: PackageTemplate) {
 615                 assert_eq!(self.height_original, merge_from.height_original);
 616                 if self.malleability == PackageMalleability::Untractable || merge_from.malleability == PackageMalleability::Untractable {
 617                         panic!("Merging template on untractable packages");
 618                 }
 619                 if !self.aggregable || !merge_from.aggregable {
 620                         panic!("Merging non aggregatable packages");
 621                 }
 622                 if let Some((_, lead_input)) = self.inputs.first() {
 623                         for (_, v) in merge_from.inputs.iter() {
 624                                 if !lead_input.is_compatible(v) { panic!("Merging outputs from differing types !"); }
 625                         }
 626                 } else { panic!("Merging template on an empty package"); }
 627                 for (k, v) in merge_from.inputs.drain(..) {
 628                         self.inputs.push((k, v));
 629                 }
 630                 //TODO: verify coverage and sanity?
 631                 if self.soonest_conf_deadline > merge_from.soonest_conf_deadline {
 632                         self.soonest_conf_deadline = merge_from.soonest_conf_deadline;
 633                 }
 634                 if self.feerate_previous > merge_from.feerate_previous {
 635                         self.feerate_previous = merge_from.feerate_previous;
 636                 }
 637                 self.height_timer = cmp::min(self.height_timer, merge_from.height_timer);
 638         }
 639         /// Gets the amount of all outptus being spent by this package, only valid for malleable
 640         /// packages.
 641         pub(crate) fn package_amount(&self) -> u64 {
 642                 let mut amounts = 0;
 643                 for (_, outp) in self.inputs.iter() {
 644                         amounts += outp.amount();
 645                 }
 646                 amounts
 647         }
 648         pub(crate) fn package_locktime(&self, current_height: u32) -> u32 {
 649                 let locktime = self.inputs.iter().map(|(_, outp)| outp.absolute_tx_timelock(current_height))
 650                         .max().expect("There must always be at least one output to spend in a PackageTemplate");
 651
 652                 // If we ever try to aggregate a `HolderHTLCOutput`s with another output type, we'll likely
 653                 // end up with an incorrect transaction locktime since the counterparty has included it in
 654                 // its HTLC signature. This should never happen unless we decide to aggregate outputs across
 655                 // different channel commitments.
 656                 #[cfg(debug_assertions)] {
 657                         if self.inputs.iter().any(|(_, outp)|
 658                                 if let PackageSolvingData::HolderHTLCOutput(outp) = outp {
 659                                         outp.preimage.is_some()
 660                                 } else {
 661                                         false
 662                                 }
 663                         ) {
 664                                 debug_assert_eq!(locktime, 0);
 665                         };
 666                         for timeout_htlc_expiry in self.inputs.iter().filter_map(|(_, outp)|
 667                                 if let PackageSolvingData::HolderHTLCOutput(outp) = outp {
 668                                         if outp.preimage.is_none() {
 669                                                 Some(outp.cltv_expiry)
 670                                         } else { None }
 671                                 } else { None }
 672                         ) {
 673                                 debug_assert_eq!(locktime, timeout_htlc_expiry);
 674                         }
 675                 }
 676
 677                 locktime
 678         }
 679         pub(crate) fn package_weight(&self, destination_script: &Script) -> usize {
 680                 let mut inputs_weight = 0;
 681                 let mut witnesses_weight = 2; // count segwit flags
 682                 for (_, outp) in self.inputs.iter() {
 683                         // previous_out_point: 36 bytes ; var_int: 1 byte ; sequence: 4 bytes
 684                         inputs_weight += 41 * WITNESS_SCALE_FACTOR;
 685                         witnesses_weight += outp.weight();
 686                 }
 687                 // version: 4 bytes ; count_tx_in: 1 byte ; count_tx_out: 1 byte ; lock_time: 4 bytes
 688                 let transaction_weight = 10 * WITNESS_SCALE_FACTOR;
 689                 // value: 8 bytes ; var_int: 1 byte ; pk_script: `destination_script.len()`
 690                 let output_weight = (8 + 1 + destination_script.len()) * WITNESS_SCALE_FACTOR;
 691                 inputs_weight + witnesses_weight + transaction_weight + output_weight
 692         }
 693         #[cfg(anchors)]
 694         pub(crate) fn construct_malleable_package_with_external_funding<Signer: WriteableEcdsaChannelSigner>(
 695                 &self, onchain_handler: &mut OnchainTxHandler<Signer>,
 696         ) -> Option<Vec<ExternalHTLCClaim>> {
 697                 debug_assert!(self.requires_external_funding());
 698                 let mut htlcs: Option<Vec<ExternalHTLCClaim>> = None;
 699                 for (previous_output, input) in &self.inputs {
 700                         match input {
 701                                 PackageSolvingData::HolderHTLCOutput(ref outp) => {
 702                                         debug_assert!(outp.opt_anchors());
 703                                         onchain_handler.generate_external_htlc_claim(&previous_output, &outp.preimage).map(|htlc| {
 704                                                 htlcs.get_or_insert_with(|| Vec::with_capacity(self.inputs.len())).push(htlc);
 705                                         });
 706                                 }
 707                                 _ => debug_assert!(false, "Expected HolderHTLCOutputs to not be aggregated with other input types"),
 708                         }
 709                 }
 710                 htlcs
 711         }
 712         pub(crate) fn finalize_malleable_package<L: Deref, Signer: WriteableEcdsaChannelSigner>(
 713                 &self, current_height: u32, onchain_handler: &mut OnchainTxHandler<Signer>, value: u64,
 714                 destination_script: Script, logger: &L
 715         ) -> Option<Transaction> where L::Target: Logger {
 716                 debug_assert!(self.is_malleable());
 717                 let mut bumped_tx = Transaction {
 718                         version: 2,
 719                         lock_time: PackedLockTime(self.package_locktime(current_height)),
 720                         input: vec![],
 721                         output: vec![TxOut {
 722                                 script_pubkey: destination_script,
 723                                 value,
 724                         }],
 725                 };
 726                 for (outpoint, _) in self.inputs.iter() {
 727                         bumped_tx.input.push(TxIn {
 728                                 previous_output: *outpoint,
 729                                 script_sig: Script::new(),
 730                                 sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
 731                                 witness: Witness::new(),
 732                         });
 733                 }
 734                 for (i, (outpoint, out)) in self.inputs.iter().enumerate() {
 735                         log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 736                         if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { return None; }
 737                 }
 738                 log_debug!(logger, "Finalized transaction {} ready to broadcast", bumped_tx.txid());
 739                 Some(bumped_tx)
 740         }
 741         pub(crate) fn finalize_untractable_package<L: Deref, Signer: WriteableEcdsaChannelSigner>(
 742                 &self, onchain_handler: &mut OnchainTxHandler<Signer>, logger: &L,
 743         ) -> Option<Transaction> where L::Target: Logger {
 744                 debug_assert!(!self.is_malleable());
 745                 if let Some((outpoint, outp)) = self.inputs.first() {
 746                         if let Some(final_tx) = outp.get_finalized_tx(outpoint, onchain_handler) {
 747                                 log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout);
 748                                 log_debug!(logger, "Finalized transaction {} ready to broadcast", final_tx.txid());
 749                                 return Some(final_tx);
 750                         }
 751                         return None;
 752                 } else { panic!("API Error: Package must not be inputs empty"); }
 753         }
 754         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 755         /// 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
 756         /// height that once reached we should generate a new bumped "version" of the claim tx to be sure that we safely claim outputs before
 757         /// that our counterparty can do so. If timelock expires soon, height timer is going to be scaled down in consequence to increase
 758         /// frequency of the bump and so increase our bets of success.
 759         pub(crate) fn get_height_timer(&self, current_height: u32) -> u32 {
 760                 if self.soonest_conf_deadline <= current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL {
 761                         return current_height + HIGH_FREQUENCY_BUMP_INTERVAL
 762                 } else if self.soonest_conf_deadline - current_height <= LOW_FREQUENCY_BUMP_INTERVAL {
 763                         return current_height + MIDDLE_FREQUENCY_BUMP_INTERVAL
 764                 }
 765                 current_height + LOW_FREQUENCY_BUMP_INTERVAL
 766         }
 767
 768         /// Returns value in satoshis to be included as package outgoing output amount and feerate
 769         /// which was used to generate the value. Will not return less than `dust_limit_sats` for the
 770         /// value.
 771         pub(crate) fn compute_package_output<F: Deref, L: Deref>(
 772                 &self, predicted_weight: usize, dust_limit_sats: u64, force_feerate_bump: bool,
 773                 fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 774         ) -> Option<(u64, u64)>
 775         where
 776                 F::Target: FeeEstimator,
 777                 L::Target: Logger,
 778         {
 779                 debug_assert!(self.malleability == PackageMalleability::Malleable, "The package output is fixed for non-malleable packages");
 780                 let input_amounts = self.package_amount();
 781                 assert!(dust_limit_sats as i64 > 0, "Output script must be broadcastable/have a 'real' dust limit.");
 782                 // If old feerate is 0, first iteration of this claim, use normal fee calculation
 783                 if self.feerate_previous != 0 {
 784                         if let Some((new_fee, feerate)) = feerate_bump(
 785                                 predicted_weight, input_amounts, self.feerate_previous, force_feerate_bump,
 786                                 fee_estimator, logger,
 787                         ) {
 788                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 789                         }
 790                 } else {
 791                         if let Some((new_fee, feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 792                                 return Some((cmp::max(input_amounts as i64 - new_fee as i64, dust_limit_sats as i64) as u64, feerate));
 793                         }
 794                 }
 795                 None
 796         }
 797
 798         #[cfg(anchors)]
 799         /// Computes a feerate based on the given confirmation target. If a previous feerate was used,
 800         /// the new feerate is below it, and `force_feerate_bump` is set, we'll use a 25% increase of
 801         /// the previous feerate instead of the new feerate.
 802         pub(crate) fn compute_package_feerate<F: Deref>(
 803                 &self, fee_estimator: &LowerBoundedFeeEstimator<F>, conf_target: ConfirmationTarget,
 804                 force_feerate_bump: bool,
 805         ) -> u32 where F::Target: FeeEstimator {
 806                 let feerate_estimate = fee_estimator.bounded_sat_per_1000_weight(conf_target);
 807                 if self.feerate_previous != 0 {
 808                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 809                         if feerate_estimate as u64 > self.feerate_previous {
 810                                 feerate_estimate
 811                         } else if !force_feerate_bump {
 812                                 self.feerate_previous.try_into().unwrap_or(u32::max_value())
 813                         } else {
 814                                 // ...else just increase the previous feerate by 25% (because that's a nice number)
 815                                 (self.feerate_previous + (self.feerate_previous / 4)).try_into().unwrap_or(u32::max_value())
 816                         }
 817                 } else {
 818                         feerate_estimate
 819                 }
 820         }
 821
 822         /// Determines whether a package contains an input which must have additional external inputs
 823         /// attached to help the spending transaction reach confirmation.
 824         pub(crate) fn requires_external_funding(&self) -> bool {
 825                 self.inputs.iter().find(|input| match input.1 {
 826                         PackageSolvingData::HolderFundingOutput(ref outp) => outp.opt_anchors(),
 827                         PackageSolvingData::HolderHTLCOutput(ref outp) => outp.opt_anchors(),
 828                         _ => false,
 829                 }).is_some()
 830         }
 831
 832         pub (crate) fn build_package(txid: Txid, vout: u32, input_solving_data: PackageSolvingData, soonest_conf_deadline: u32, aggregable: bool, height_original: u32) -> Self {
 833                 let (malleability, aggregable) = Self::map_output_type_flags(&input_solving_data);
 834                 let mut inputs = Vec::with_capacity(1);
 835                 inputs.push((BitcoinOutPoint { txid, vout }, input_solving_data));
 836                 PackageTemplate {
 837                         inputs,
 838                         malleability,
 839                         soonest_conf_deadline,
 840                         aggregable,
 841                         feerate_previous: 0,
 842                         height_timer: height_original,
 843                         height_original,
 844                 }
 845         }
 846
 847         fn map_output_type_flags(input_solving_data: &PackageSolvingData) -> (PackageMalleability, bool) {
 848                 let (malleability, aggregable) = match input_solving_data {
 849                         PackageSolvingData::RevokedOutput(RevokedOutput { is_counterparty_balance_on_anchors: Some(()), .. }) => { (PackageMalleability::Malleable, false) },
 850                         PackageSolvingData::RevokedOutput(RevokedOutput { is_counterparty_balance_on_anchors: None, .. }) => { (PackageMalleability::Malleable, true) },
 851                         PackageSolvingData::RevokedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 852                         PackageSolvingData::CounterpartyOfferedHTLCOutput(..) => { (PackageMalleability::Malleable, true) },
 853                         PackageSolvingData::CounterpartyReceivedHTLCOutput(..) => { (PackageMalleability::Malleable, false) },
 854                         PackageSolvingData::HolderHTLCOutput(..) => { (PackageMalleability::Untractable, false) },
 855                         PackageSolvingData::HolderFundingOutput(..) => { (PackageMalleability::Untractable, false) },
 856                 };
 857                 (malleability, aggregable)
 858         }
 859 }
 860
 861 impl Writeable for PackageTemplate {
 862         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 863                 writer.write_all(&(self.inputs.len() as u64).to_be_bytes())?;
 864                 for (ref outpoint, ref rev_outp) in self.inputs.iter() {
 865                         outpoint.write(writer)?;
 866                         rev_outp.write(writer)?;
 867                 }
 868                 write_tlv_fields!(writer, {
 869                         (0, self.soonest_conf_deadline, required),
 870                         (2, self.feerate_previous, required),
 871                         (4, self.height_original, required),
 872                         (6, self.height_timer, required)
 873                 });
 874                 Ok(())
 875         }
 876 }
 877
 878 impl Readable for PackageTemplate {
 879         fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 880                 let inputs_count = <u64 as Readable>::read(reader)?;
 881                 let mut inputs: Vec<(BitcoinOutPoint, PackageSolvingData)> = Vec::with_capacity(cmp::min(inputs_count as usize, MAX_ALLOC_SIZE / 128));
 882                 for _ in 0..inputs_count {
 883                         let outpoint = Readable::read(reader)?;
 884                         let rev_outp = Readable::read(reader)?;
 885                         inputs.push((outpoint, rev_outp));
 886                 }
 887                 let (malleability, aggregable) = if let Some((_, lead_input)) = inputs.first() {
 888                         Self::map_output_type_flags(&lead_input)
 889                 } else { return Err(DecodeError::InvalidValue); };
 890                 let mut soonest_conf_deadline = 0;
 891                 let mut feerate_previous = 0;
 892                 let mut height_timer = None;
 893                 let mut height_original = 0;
 894                 read_tlv_fields!(reader, {
 895                         (0, soonest_conf_deadline, required),
 896                         (2, feerate_previous, required),
 897                         (4, height_original, required),
 898                         (6, height_timer, option),
 899                 });
 900                 if height_timer.is_none() {
 901                         height_timer = Some(height_original);
 902                 }
 903                 Ok(PackageTemplate {
 904                         inputs,
 905                         malleability,
 906                         soonest_conf_deadline,
 907                         aggregable,
 908                         feerate_previous,
 909                         height_timer: height_timer.unwrap(),
 910                         height_original,
 911                 })
 912         }
 913 }
 914
 915 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 916 /// weight. We start with the highest priority feerate returned by the node's fee estimator then
 917 /// fall-back to lower priorities until we have enough value available to suck from.
 918 ///
 919 /// If the proposed fee is less than the available spent output's values, we return the proposed
 920 /// fee and the corresponding updated feerate. If the proposed fee is equal or more than the
 921 /// available spent output's values, we return nothing
 922 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)>
 923         where F::Target: FeeEstimator,
 924               L::Target: Logger,
 925 {
 926         let mut updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64;
 927         let mut fee = updated_feerate * (predicted_weight as u64) / 1000;
 928         if input_amounts <= fee {
 929                 updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal) as u64;
 930                 fee = updated_feerate * (predicted_weight as u64) / 1000;
 931                 if input_amounts <= fee {
 932                         updated_feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background) as u64;
 933                         fee = updated_feerate * (predicted_weight as u64) / 1000;
 934                         if input_amounts <= fee {
 935                                 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)",
 936                                         fee, input_amounts);
 937                                 None
 938                         } else {
 939                                 log_warn!(logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 940                                         input_amounts);
 941                                 Some((fee, updated_feerate))
 942                         }
 943                 } else {
 944                         log_warn!(logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 945                                 input_amounts);
 946                         Some((fee, updated_feerate))
 947                 }
 948         } else {
 949                 Some((fee, updated_feerate))
 950         }
 951 }
 952
 953 /// Attempt to propose a bumping fee for a transaction from its spent output's values and predicted
 954 /// weight. If feerates proposed by the fee-estimator have been increasing since last fee-bumping
 955 /// attempt, use them. If `force_feerate_bump` is set, we bump the feerate by 25% of the previous
 956 /// feerate, or just use the previous feerate otherwise. If a feerate bump did happen, we also
 957 /// verify that those bumping heuristics respect BIP125 rules 3) and 4) and if required adjust the
 958 /// new fee to meet the RBF policy requirement.
 959 fn feerate_bump<F: Deref, L: Deref>(
 960         predicted_weight: usize, input_amounts: u64, previous_feerate: u64, force_feerate_bump: bool,
 961         fee_estimator: &LowerBoundedFeeEstimator<F>, logger: &L,
 962 ) -> Option<(u64, u64)>
 963 where
 964         F::Target: FeeEstimator,
 965         L::Target: Logger,
 966 {
 967         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 968         let (new_fee, new_feerate) = if let Some((new_fee, new_feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) {
 969                 if new_feerate > previous_feerate {
 970                         (new_fee, new_feerate)
 971                 } else if !force_feerate_bump {
 972                         let previous_fee = previous_feerate * (predicted_weight as u64) / 1000;
 973                         (previous_fee, previous_feerate)
 974                 } else {
 975                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 976                         let bumped_feerate = previous_feerate + (previous_feerate / 4);
 977                         let bumped_fee = bumped_feerate * (predicted_weight as u64) / 1000;
 978                         if input_amounts <= bumped_fee {
 979                                 log_warn!(logger, "Can't 25% bump new claiming tx, amount {} is too small", input_amounts);
 980                                 return None;
 981                         }
 982                         (bumped_fee, bumped_feerate)
 983                 }
 984         } else {
 985                 log_warn!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", input_amounts);
 986                 return None;
 987         };
 988
 989         // Our feerates should never decrease. If it hasn't changed though, we just need to
 990         // rebroadcast/re-sign the previous claim.
 991         debug_assert!(new_feerate >= previous_feerate);
 992         if new_feerate == previous_feerate {
 993                 return Some((new_fee, new_feerate));
 994         }
 995
 996         let previous_fee = previous_feerate * (predicted_weight as u64) / 1000;
 997         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * (predicted_weight as u64) / 1000;
 998         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 999         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
1000         //      * 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.
1001         let new_fee = if new_fee < previous_fee + min_relay_fee {
1002                 new_fee + previous_fee + min_relay_fee - new_fee
1003         } else {
1004                 new_fee
1005         };
1006         Some((new_fee, new_fee * 1000 / (predicted_weight as u64)))
1007 }
1008
1009 #[cfg(test)]
1010 mod tests {
1011         use crate::chain::package::{CounterpartyOfferedHTLCOutput, CounterpartyReceivedHTLCOutput, HolderHTLCOutput, PackageTemplate, PackageSolvingData, RevokedOutput, WEIGHT_REVOKED_OUTPUT, weight_offered_htlc, weight_received_htlc};
1012         use crate::chain::Txid;
1013         use crate::ln::chan_utils::HTLCOutputInCommitment;
1014         use crate::ln::{PaymentPreimage, PaymentHash};
1015
1016         use bitcoin::blockdata::constants::WITNESS_SCALE_FACTOR;
1017         use bitcoin::blockdata::script::Script;
1018         use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
1019
1020         use bitcoin::hashes::hex::FromHex;
1021
1022         use bitcoin::secp256k1::{PublicKey,SecretKey};
1023         use bitcoin::secp256k1::Secp256k1;
1024
1025         macro_rules! dumb_revk_output {
1026                 ($secp_ctx: expr, $is_counterparty_balance_on_anchors: expr) => {
1027                         {
1028                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
1029                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
1030                                 PackageSolvingData::RevokedOutput(RevokedOutput::build(dumb_point, dumb_point, dumb_point, dumb_scalar, 0, 0, $is_counterparty_balance_on_anchors))
1031                         }
1032                 }
1033         }
1034
1035         macro_rules! dumb_counterparty_output {
1036                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
1037                         {
1038                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
1039                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
1040                                 let hash = PaymentHash([1; 32]);
1041                                 let htlc = HTLCOutputInCommitment { offered: true, amount_msat: $amt, cltv_expiry: 0, payment_hash: hash, transaction_output_index: None };
1042                                 PackageSolvingData::CounterpartyReceivedHTLCOutput(CounterpartyReceivedHTLCOutput::build(dumb_point, dumb_point, dumb_point, htlc, $opt_anchors))
1043                         }
1044                 }
1045         }
1046
1047         macro_rules! dumb_counterparty_offered_output {
1048                 ($secp_ctx: expr, $amt: expr, $opt_anchors: expr) => {
1049                         {
1050                                 let dumb_scalar = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
1051                                 let dumb_point = PublicKey::from_secret_key(&$secp_ctx, &dumb_scalar);
1052                                 let hash = PaymentHash([1; 32]);
1053                                 let preimage = PaymentPreimage([2;32]);
1054                                 let htlc = HTLCOutputInCommitment { offered: false, amount_msat: $amt, cltv_expiry: 1000, payment_hash: hash, transaction_output_index: None };
1055                                 PackageSolvingData::CounterpartyOfferedHTLCOutput(CounterpartyOfferedHTLCOutput::build(dumb_point, dumb_point, dumb_point, preimage, htlc, $opt_anchors))
1056                         }
1057                 }
1058         }
1059
1060         macro_rules! dumb_htlc_output {
1061                 () => {
1062                         {
1063                                 let preimage = PaymentPreimage([2;32]);
1064                                 PackageSolvingData::HolderHTLCOutput(HolderHTLCOutput::build_accepted(preimage, 0, false))
1065                         }
1066                 }
1067         }
1068
1069         #[test]
1070         #[should_panic]
1071         fn test_package_differing_heights() {
1072                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1073                 let secp_ctx = Secp256k1::new();
1074                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1075
1076                 let mut package_one_hundred = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1077                 let package_two_hundred = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 200);
1078                 package_one_hundred.merge_package(package_two_hundred);
1079         }
1080
1081         #[test]
1082         #[should_panic]
1083         fn test_package_untractable_merge_to() {
1084                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1085                 let secp_ctx = Secp256k1::new();
1086                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1087                 let htlc_outp = dumb_htlc_output!();
1088
1089                 let mut untractable_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1090                 let malleable_package = PackageTemplate::build_package(txid, 1, htlc_outp.clone(), 1000, true, 100);
1091                 untractable_package.merge_package(malleable_package);
1092         }
1093
1094         #[test]
1095         #[should_panic]
1096         fn test_package_untractable_merge_from() {
1097                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1098                 let secp_ctx = Secp256k1::new();
1099                 let htlc_outp = dumb_htlc_output!();
1100                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1101
1102                 let mut malleable_package = PackageTemplate::build_package(txid, 0, htlc_outp.clone(), 1000, true, 100);
1103                 let untractable_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1104                 malleable_package.merge_package(untractable_package);
1105         }
1106
1107         #[test]
1108         #[should_panic]
1109         fn test_package_noaggregation_to() {
1110                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1111                 let secp_ctx = Secp256k1::new();
1112                 let revk_outp = dumb_revk_output!(secp_ctx, true);
1113
1114                 let mut noaggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, false, 100);
1115                 let aggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1116                 noaggregation_package.merge_package(aggregation_package);
1117         }
1118
1119         #[test]
1120         #[should_panic]
1121         fn test_package_noaggregation_from() {
1122                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1123                 let secp_ctx = Secp256k1::new();
1124                 let revk_outp = dumb_revk_output!(secp_ctx, true);
1125
1126                 let mut aggregation_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1127                 let noaggregation_package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, false, 100);
1128                 aggregation_package.merge_package(noaggregation_package);
1129         }
1130
1131         #[test]
1132         #[should_panic]
1133         fn test_package_empty() {
1134                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1135                 let secp_ctx = Secp256k1::new();
1136                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1137
1138                 let mut empty_package = PackageTemplate::build_package(txid, 0, revk_outp.clone(), 1000, true, 100);
1139                 empty_package.inputs = vec![];
1140                 let package = PackageTemplate::build_package(txid, 1, revk_outp.clone(), 1000, true, 100);
1141                 empty_package.merge_package(package);
1142         }
1143
1144         #[test]
1145         #[should_panic]
1146         fn test_package_differing_categories() {
1147                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1148                 let secp_ctx = Secp256k1::new();
1149                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1150                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 0, false);
1151
1152                 let mut revoked_package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1153                 let counterparty_package = PackageTemplate::build_package(txid, 1, counterparty_outp, 1000, true, 100);
1154                 revoked_package.merge_package(counterparty_package);
1155         }
1156
1157         #[test]
1158         fn test_package_split_malleable() {
1159                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1160                 let secp_ctx = Secp256k1::new();
1161                 let revk_outp_one = dumb_revk_output!(secp_ctx, false);
1162                 let revk_outp_two = dumb_revk_output!(secp_ctx, false);
1163                 let revk_outp_three = dumb_revk_output!(secp_ctx, false);
1164
1165                 let mut package_one = PackageTemplate::build_package(txid, 0, revk_outp_one, 1000, true, 100);
1166                 let package_two = PackageTemplate::build_package(txid, 1, revk_outp_two, 1000, true, 100);
1167                 let package_three = PackageTemplate::build_package(txid, 2, revk_outp_three, 1000, true, 100);
1168
1169                 package_one.merge_package(package_two);
1170                 package_one.merge_package(package_three);
1171                 assert_eq!(package_one.outpoints().len(), 3);
1172
1173                 if let Some(split_package) = package_one.split_package(&BitcoinOutPoint { txid, vout: 1 }) {
1174                         // Packages attributes should be identical
1175                         assert!(split_package.is_malleable());
1176                         assert_eq!(split_package.soonest_conf_deadline, package_one.soonest_conf_deadline);
1177                         assert_eq!(split_package.aggregable, package_one.aggregable);
1178                         assert_eq!(split_package.feerate_previous, package_one.feerate_previous);
1179                         assert_eq!(split_package.height_timer, package_one.height_timer);
1180                         assert_eq!(split_package.height_original, package_one.height_original);
1181                 } else { panic!(); }
1182                 assert_eq!(package_one.outpoints().len(), 2);
1183         }
1184
1185         #[test]
1186         fn test_package_split_untractable() {
1187                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1188                 let htlc_outp_one = dumb_htlc_output!();
1189
1190                 let mut package_one = PackageTemplate::build_package(txid, 0, htlc_outp_one, 1000, true, 100);
1191                 let ret_split = package_one.split_package(&BitcoinOutPoint { txid, vout: 0});
1192                 assert!(ret_split.is_none());
1193         }
1194
1195         #[test]
1196         fn test_package_timer() {
1197                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1198                 let secp_ctx = Secp256k1::new();
1199                 let revk_outp = dumb_revk_output!(secp_ctx, false);
1200
1201                 let mut package = PackageTemplate::build_package(txid, 0, revk_outp, 1000, true, 100);
1202                 assert_eq!(package.timer(), 100);
1203                 package.set_timer(101);
1204                 assert_eq!(package.timer(), 101);
1205         }
1206
1207         #[test]
1208         fn test_package_amounts() {
1209                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1210                 let secp_ctx = Secp256k1::new();
1211                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, false);
1212
1213                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1214                 assert_eq!(package.package_amount(), 1000);
1215         }
1216
1217         #[test]
1218         fn test_package_weight() {
1219                 let txid = Txid::from_hex("c2d4449afa8d26140898dd54d3390b057ba2a5afcf03ba29d7dc0d8b9ffe966e").unwrap();
1220                 let secp_ctx = Secp256k1::new();
1221
1222                 // (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)
1223                 let weight_sans_output = (4 + 4 + 1 + 36 + 4 + 1 + 1 + 8 + 1) * WITNESS_SCALE_FACTOR + 2;
1224
1225                 {
1226                         let revk_outp = dumb_revk_output!(secp_ctx, false);
1227                         let package = PackageTemplate::build_package(txid, 0, revk_outp, 0, true, 100);
1228                         assert_eq!(package.package_weight(&Script::new()),  weight_sans_output + WEIGHT_REVOKED_OUTPUT as usize);
1229                 }
1230
1231                 {
1232                         for &opt_anchors in [false, true].iter() {
1233                                 let counterparty_outp = dumb_counterparty_output!(secp_ctx, 1_000_000, opt_anchors);
1234                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1235                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_received_htlc(opt_anchors) as usize);
1236                         }
1237                 }
1238
1239                 {
1240                         for &opt_anchors in [false, true].iter() {
1241                                 let counterparty_outp = dumb_counterparty_offered_output!(secp_ctx, 1_000_000, opt_anchors);
1242                                 let package = PackageTemplate::build_package(txid, 0, counterparty_outp, 1000, true, 100);
1243                                 assert_eq!(package.package_weight(&Script::new()), weight_sans_output + weight_offered_htlc(opt_anchors) as usize);
1244                         }
1245                 }
1246         }
1247 }