_ Git - rust-lightning/blob - lightning/src/ln/onchaintx.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 //! The logic to build claims and bump in-flight transactions until confirmations.
  11 //!
  12 //! OnchainTxHandler objetcs are fully-part of ChannelMonitor and encapsulates all
  13 //! building, tracking, bumping and notifications functions.
  14
  15 use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
  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::{Secp256k1, Signature};
  22 use bitcoin::secp256k1;
  23
  24 use ln::msgs::DecodeError;
  25 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
  26 use ln::channelmanager::PaymentPreimage;
  27 use ln::chan_utils;
  28 use ln::chan_utils::{TxCreationKeys, LocalCommitmentTransaction};
  29 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
  30 use chain::keysinterface::ChannelKeys;
  31 use util::logger::Logger;
  32 use util::ser::{Readable, Writer, Writeable};
  33 use util::byte_utils;
  34
  35 use std::collections::{HashMap, hash_map};
  36 use std::cmp;
  37 use std::ops::Deref;
  38
  39 const MAX_ALLOC_SIZE: usize = 64*1024;
  40
  41 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
  42 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
  43 #[derive(Clone, PartialEq)]
  44 enum OnchainEvent {
  45         /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
  46         /// bump-txn candidate buffer.
  47         Claim {
  48                 claim_request: Txid,
  49         },
  50         /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
  51         /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
  52         /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
  53         ContentiousOutpoint {
  54                 outpoint: BitcoinOutPoint,
  55                 input_material: InputMaterial,
  56         }
  57 }
  58
  59 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
  60 #[derive(Clone, PartialEq)]
  61 pub struct ClaimTxBumpMaterial {
  62         // At every block tick, used to check if pending claiming tx is taking too
  63         // much time for confirmation and we need to bump it.
  64         height_timer: Option<u32>,
  65         // Tracked in case of reorg to wipe out now-superflous bump material
  66         feerate_previous: u32,
  67         // Soonest timelocks among set of outpoints claimed, used to compute
  68         // a priority of not feerate
  69         soonest_timelock: u32,
  70         // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
  71         per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
  72 }
  73
  74 impl Writeable for ClaimTxBumpMaterial  {
  75         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
  76                 self.height_timer.write(writer)?;
  77                 writer.write_all(&byte_utils::be32_to_array(self.feerate_previous))?;
  78                 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
  79                 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
  80                 for (outp, tx_material) in self.per_input_material.iter() {
  81                         outp.write(writer)?;
  82                         tx_material.write(writer)?;
  83                 }
  84                 Ok(())
  85         }
  86 }
  87
  88 impl Readable for ClaimTxBumpMaterial {
  89         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
  90                 let height_timer = Readable::read(reader)?;
  91                 let feerate_previous = Readable::read(reader)?;
  92                 let soonest_timelock = Readable::read(reader)?;
  93                 let per_input_material_len: u64 = Readable::read(reader)?;
  94                 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
  95                 for _ in 0 ..per_input_material_len {
  96                         let outpoint = Readable::read(reader)?;
  97                         let input_material = Readable::read(reader)?;
  98                         per_input_material.insert(outpoint, input_material);
  99                 }
 100                 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
 101         }
 102 }
 103
 104 #[derive(PartialEq, Clone, Copy)]
 105 pub(crate) enum InputDescriptors {
 106         RevokedOfferedHTLC,
 107         RevokedReceivedHTLC,
 108         OfferedHTLC,
 109         ReceivedHTLC,
 110         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 111 }
 112
 113 impl Writeable for InputDescriptors {
 114         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 115                 match self {
 116                         &InputDescriptors::RevokedOfferedHTLC => {
 117                                 writer.write_all(&[0; 1])?;
 118                         },
 119                         &InputDescriptors::RevokedReceivedHTLC => {
 120                                 writer.write_all(&[1; 1])?;
 121                         },
 122                         &InputDescriptors::OfferedHTLC => {
 123                                 writer.write_all(&[2; 1])?;
 124                         },
 125                         &InputDescriptors::ReceivedHTLC => {
 126                                 writer.write_all(&[3; 1])?;
 127                         }
 128                         &InputDescriptors::RevokedOutput => {
 129                                 writer.write_all(&[4; 1])?;
 130                         }
 131                 }
 132                 Ok(())
 133         }
 134 }
 135
 136 impl Readable for InputDescriptors {
 137         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 138                 let input_descriptor = match <u8 as Readable>::read(reader)? {
 139                         0 => {
 140                                 InputDescriptors::RevokedOfferedHTLC
 141                         },
 142                         1 => {
 143                                 InputDescriptors::RevokedReceivedHTLC
 144                         },
 145                         2 => {
 146                                 InputDescriptors::OfferedHTLC
 147                         },
 148                         3 => {
 149                                 InputDescriptors::ReceivedHTLC
 150                         },
 151                         4 => {
 152                                 InputDescriptors::RevokedOutput
 153                         }
 154                         _ => return Err(DecodeError::InvalidValue),
 155                 };
 156                 Ok(input_descriptor)
 157         }
 158 }
 159
 160 macro_rules! subtract_high_prio_fee {
 161         ($logger: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 162                 {
 163                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority).into();
 164                         let mut fee = $used_feerate as u64 * $predicted_weight / 1000;
 165                         if $value <= fee {
 166                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal).into();
 167                                 fee = $used_feerate as u64 * $predicted_weight / 1000;
 168                                 if $value <= fee.into() {
 169                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background).into();
 170                                         fee = $used_feerate as u64 * $predicted_weight / 1000;
 171                                         if $value <= fee {
 172                                                 log_error!($logger, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 173                                                         fee, $value);
 174                                                 false
 175                                         } else {
 176                                                 log_warn!($logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 177                                                         $value);
 178                                                 $value -= fee;
 179                                                 true
 180                                         }
 181                                 } else {
 182                                         log_warn!($logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 183                                                 $value);
 184                                         $value -= fee;
 185                                         true
 186                                 }
 187                         } else {
 188                                 $value -= fee;
 189                                 true
 190                         }
 191                 }
 192         }
 193 }
 194
 195 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 196         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 197                 match Readable::read(reader)? {
 198                         0u8 => Ok(None),
 199                         1u8 => {
 200                                 let vlen: u64 = Readable::read(reader)?;
 201                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<Option<(usize, Signature)>>()));
 202                                 for _ in 0..vlen {
 203                                         ret.push(match Readable::read(reader)? {
 204                                                 0u8 => None,
 205                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 206                                                 _ => return Err(DecodeError::InvalidValue)
 207                                         });
 208                                 }
 209                                 Ok(Some(ret))
 210                         },
 211                         _ => Err(DecodeError::InvalidValue),
 212                 }
 213         }
 214 }
 215
 216 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 217         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 218                 match self {
 219                         &Some(ref vec) => {
 220                                 1u8.write(writer)?;
 221                                 (vec.len() as u64).write(writer)?;
 222                                 for opt in vec.iter() {
 223                                         match opt {
 224                                                 &Some((ref idx, ref sig)) => {
 225                                                         1u8.write(writer)?;
 226                                                         (*idx as u64).write(writer)?;
 227                                                         sig.write(writer)?;
 228                                                 },
 229                                                 &None => 0u8.write(writer)?,
 230                                         }
 231                                 }
 232                         },
 233                         &None => 0u8.write(writer)?,
 234                 }
 235                 Ok(())
 236         }
 237 }
 238
 239
 240 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 241 /// do RBF bumping if possible.
 242 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 243         destination_script: Script,
 244         local_commitment: Option<LocalCommitmentTransaction>,
 245         // local_htlc_sigs and prev_local_htlc_sigs are in the order as they appear in the commitment
 246         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 247         // the set of HTLCs in the LocalCommitmentTransaction (including those which do not appear in
 248         // the commitment transaction).
 249         local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 250         prev_local_commitment: Option<LocalCommitmentTransaction>,
 251         prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 252         on_local_tx_csv: u16,
 253
 254         key_storage: ChanSigner,
 255
 256         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 257         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 258         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 259         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 260         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 261         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 262         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 263         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 264         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 265         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 266         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 267         #[cfg(test)] // Used in functional_test to verify sanitization
 268         pub pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 269         #[cfg(not(test))]
 270         pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 271
 272         // Used to link outpoints claimed in a connected block to a pending claim request.
 273         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 274         // Value is (pending claim request identifier, confirmation_block), identifier
 275         // is txid of the initial claiming transaction and is immutable until outpoint is
 276         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 277         // block with output gets disconnected.
 278         #[cfg(test)] // Used in functional_test to verify sanitization
 279         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 280         #[cfg(not(test))]
 281         claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 282
 283         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 284
 285         secp_ctx: Secp256k1<secp256k1::All>,
 286 }
 287
 288 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 289         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 290                 self.destination_script.write(writer)?;
 291                 self.local_commitment.write(writer)?;
 292                 self.local_htlc_sigs.write(writer)?;
 293                 self.prev_local_commitment.write(writer)?;
 294                 self.prev_local_htlc_sigs.write(writer)?;
 295
 296                 self.on_local_tx_csv.write(writer)?;
 297
 298                 self.key_storage.write(writer)?;
 299
 300                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 301                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 302                         ancestor_claim_txid.write(writer)?;
 303                         claim_tx_data.write(writer)?;
 304                 }
 305
 306                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 307                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 308                         outp.write(writer)?;
 309                         claim_and_height.0.write(writer)?;
 310                         claim_and_height.1.write(writer)?;
 311                 }
 312
 313                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 314                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 315                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 316                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 317                         for ev in events.iter() {
 318                                 match *ev {
 319                                         OnchainEvent::Claim { ref claim_request } => {
 320                                                 writer.write_all(&[0; 1])?;
 321                                                 claim_request.write(writer)?;
 322                                         },
 323                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 324                                                 writer.write_all(&[1; 1])?;
 325                                                 outpoint.write(writer)?;
 326                                                 input_material.write(writer)?;
 327                                         }
 328                                 }
 329                         }
 330                 }
 331                 Ok(())
 332         }
 333 }
 334
 335 impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
 336         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 337                 let destination_script = Readable::read(reader)?;
 338
 339                 let local_commitment = Readable::read(reader)?;
 340                 let local_htlc_sigs = Readable::read(reader)?;
 341                 let prev_local_commitment = Readable::read(reader)?;
 342                 let prev_local_htlc_sigs = Readable::read(reader)?;
 343
 344                 let on_local_tx_csv = Readable::read(reader)?;
 345
 346                 let key_storage = Readable::read(reader)?;
 347
 348                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 349                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 350                 for _ in 0..pending_claim_requests_len {
 351                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 352                 }
 353
 354                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 355                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 356                 for _ in 0..claimable_outpoints_len {
 357                         let outpoint = Readable::read(reader)?;
 358                         let ancestor_claim_txid = Readable::read(reader)?;
 359                         let height = Readable::read(reader)?;
 360                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 361                 }
 362                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 363                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 364                 for _ in 0..waiting_threshold_conf_len {
 365                         let height_target = Readable::read(reader)?;
 366                         let events_len: u64 = Readable::read(reader)?;
 367                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 368                         for _ in 0..events_len {
 369                                 let ev = match <u8 as Readable>::read(reader)? {
 370                                         0 => {
 371                                                 let claim_request = Readable::read(reader)?;
 372                                                 OnchainEvent::Claim {
 373                                                         claim_request
 374                                                 }
 375                                         },
 376                                         1 => {
 377                                                 let outpoint = Readable::read(reader)?;
 378                                                 let input_material = Readable::read(reader)?;
 379                                                 OnchainEvent::ContentiousOutpoint {
 380                                                         outpoint,
 381                                                         input_material
 382                                                 }
 383                                         }
 384                                         _ => return Err(DecodeError::InvalidValue),
 385                                 };
 386                                 events.push(ev);
 387                         }
 388                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 389                 }
 390
 391                 Ok(OnchainTxHandler {
 392                         destination_script,
 393                         local_commitment,
 394                         local_htlc_sigs,
 395                         prev_local_commitment,
 396                         prev_local_htlc_sigs,
 397                         on_local_tx_csv,
 398                         key_storage,
 399                         claimable_outpoints,
 400                         pending_claim_requests,
 401                         onchain_events_waiting_threshold_conf,
 402                         secp_ctx: Secp256k1::new(),
 403                 })
 404         }
 405 }
 406
 407 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 408         pub(super) fn new(destination_script: Script, keys: ChanSigner, on_local_tx_csv: u16) -> Self {
 409
 410                 let key_storage = keys;
 411
 412                 OnchainTxHandler {
 413                         destination_script,
 414                         local_commitment: None,
 415                         local_htlc_sigs: None,
 416                         prev_local_commitment: None,
 417                         prev_local_htlc_sigs: None,
 418                         on_local_tx_csv,
 419                         key_storage,
 420                         pending_claim_requests: HashMap::new(),
 421                         claimable_outpoints: HashMap::new(),
 422                         onchain_events_waiting_threshold_conf: HashMap::new(),
 423
 424                         secp_ctx: Secp256k1::new(),
 425                 }
 426         }
 427
 428         pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
 429                 let mut tx_weight = 2; // count segwit flags
 430                 for inp in inputs {
 431                         // We use expected weight (and not actual) as signatures and time lock delays may vary
 432                         tx_weight +=  match inp {
 433                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 434                                 &InputDescriptors::RevokedOfferedHTLC => {
 435                                         1 + 1 + 73 + 1 + 33 + 1 + 133
 436                                 },
 437                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 438                                 &InputDescriptors::RevokedReceivedHTLC => {
 439                                         1 + 1 + 73 + 1 + 33 + 1 + 139
 440                                 },
 441                                 // number_of_witness_elements + sig_length + remotehtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
 442                                 &InputDescriptors::OfferedHTLC => {
 443                                         1 + 1 + 73 + 1 + 32 + 1 + 133
 444                                 },
 445                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 446                                 &InputDescriptors::ReceivedHTLC => {
 447                                         1 + 1 + 73 + 1 + 1 + 1 + 139
 448                                 },
 449                                 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
 450                                 &InputDescriptors::RevokedOutput => {
 451                                         1 + 1 + 73 + 1 + 1 + 1 + 77
 452                                 },
 453                         };
 454                 }
 455                 tx_weight
 456         }
 457
 458         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 459         /// 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
 460         /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
 461         /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
 462         /// frequency of the bump and so increase our bets of success.
 463         fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
 464                 if timelock_expiration <= current_height + 3 {
 465                         return current_height + 1
 466                 } else if timelock_expiration - current_height <= 15 {
 467                         return current_height + 3
 468                 }
 469                 current_height + 15
 470         }
 471
 472         /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize coutnerparty onchain) lays on the assumption of claim transactions getting confirmed before timelock expiration
 473         /// (CSV or CLTV following cases). In case of high-fee spikes, claim tx may stuck in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or Child-Pay-For-Parent.
 474         fn generate_claim_tx<F: Deref, L: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F, logger: L) -> Option<(Option<u32>, u32, Transaction)>
 475                 where F::Target: FeeEstimator,
 476                                         L::Target: Logger,
 477         {
 478                 if cached_claim_datas.per_input_material.len() == 0 { return None } // But don't prune pending claiming request yet, we may have to resurrect HTLCs
 479                 let mut inputs = Vec::new();
 480                 for outp in cached_claim_datas.per_input_material.keys() {
 481                         log_trace!(logger, "Outpoint {}:{}", outp.txid, outp.vout);
 482                         inputs.push(TxIn {
 483                                 previous_output: *outp,
 484                                 script_sig: Script::new(),
 485                                 sequence: 0xfffffffd,
 486                                 witness: Vec::new(),
 487                         });
 488                 }
 489                 let mut bumped_tx = Transaction {
 490                         version: 2,
 491                         lock_time: 0,
 492                         input: inputs,
 493                         output: vec![TxOut {
 494                                 script_pubkey: self.destination_script.clone(),
 495                                 value: 0
 496                         }],
 497                 };
 498
 499                 macro_rules! RBF_bump {
 500                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 501                                 {
 502                                         let mut used_feerate: u32;
 503                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 504                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 505                                                 let mut value = $amount;
 506                                                 if subtract_high_prio_fee!(logger, $fee_estimator, value, $predicted_weight, used_feerate) {
 507                                                         // Overflow check is done in subtract_high_prio_fee
 508                                                         ($amount - value)
 509                                                 } else {
 510                                                         log_trace!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 511                                                         return None;
 512                                                 }
 513                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 514                                         } else {
 515                                                 let fee = $old_feerate as u64 * ($predicted_weight as u64) / 750;
 516                                                 if $amount <= fee {
 517                                                         log_trace!(logger, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 518                                                         return None;
 519                                                 }
 520                                                 fee
 521                                         };
 522
 523                                         let previous_fee = $old_feerate as u64 * ($predicted_weight as u64) / 1000;
 524                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * ($predicted_weight as u64) / 1000;
 525                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 526                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 527                                         //      * 4. The replacement transaction must also pay for its own bandwidth at or above the rate set by the node's minimum relay fee setting.
 528                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 529                                                 new_fee + previous_fee + min_relay_fee - new_fee
 530                                         } else {
 531                                                 new_fee
 532                                         };
 533                                         Some((new_fee, new_fee * 1000 / ($predicted_weight as u64)))
 534                                 }
 535                         }
 536                 }
 537
 538                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 539                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 540                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 541                 let mut inputs_witnesses_weight = 0;
 542                 let mut amt = 0;
 543                 let mut dynamic_fee = true;
 544                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 545                         match per_outp_material {
 546                                 &InputMaterial::Revoked { ref input_descriptor, ref amount, .. } => {
 547                                         inputs_witnesses_weight += Self::get_witnesses_weight(&[*input_descriptor]);
 548                                         amt += *amount;
 549                                 },
 550                                 &InputMaterial::RemoteHTLC { ref preimage, ref htlc, .. } => {
 551                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 552                                         amt += htlc.amount_msat / 1000;
 553                                 },
 554                                 &InputMaterial::LocalHTLC { .. } => {
 555                                         dynamic_fee = false;
 556                                 },
 557                                 &InputMaterial::Funding { .. } => {
 558                                         dynamic_fee = false;
 559                                 }
 560                         }
 561                 }
 562                 if dynamic_fee {
 563                         let predicted_weight = (bumped_tx.get_weight() + inputs_witnesses_weight) as u64;
 564                         let mut new_feerate;
 565                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 566                         if cached_claim_datas.feerate_previous != 0 {
 567                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight) {
 568                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 569                                         if new_fee as u64 > amt {
 570                                                 bumped_tx.output[0].value = 0;
 571                                         } else {
 572                                                 bumped_tx.output[0].value = amt - new_fee as u64;
 573                                         }
 574                                         new_feerate = feerate;
 575                                 } else { return None; }
 576                         } else {
 577                                 if subtract_high_prio_fee!(logger, fee_estimator, amt, predicted_weight, new_feerate) {
 578                                         bumped_tx.output[0].value = amt;
 579                                 } else { return None; }
 580                         }
 581                         assert!(new_feerate != 0);
 582
 583                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 584                                 match per_outp_material {
 585                                         &InputMaterial::Revoked { ref per_commitment_point, ref remote_delayed_payment_base_key, ref remote_htlc_base_key, ref per_commitment_key, ref input_descriptor, ref amount, ref htlc, ref on_remote_tx_csv } => {
 586                                                 if let Ok(chan_keys) = TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, remote_delayed_payment_base_key, remote_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
 587
 588                                                         let witness_script = if let Some(ref htlc) = *htlc {
 589                                                                 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key)
 590                                                         } else {
 591                                                                 chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, *on_remote_tx_csv, &chan_keys.a_delayed_payment_key)
 592                                                         };
 593
 594                                                         if let Ok(sig) = self.key_storage.sign_justice_transaction(&bumped_tx, i, *amount, &per_commitment_key, htlc, &self.secp_ctx) {
 595                                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 596                                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 597                                                                 if htlc.is_some() {
 598                                                                         bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
 599                                                                 } else {
 600                                                                         bumped_tx.input[i].witness.push(vec!(1));
 601                                                                 }
 602                                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 603                                                         } else { return None; }
 604                                                         //TODO: panic ?
 605
 606                                                         log_trace!(logger, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_local" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
 607                                                 }
 608                                         },
 609                                         &InputMaterial::RemoteHTLC { ref per_commitment_point, ref remote_delayed_payment_base_key, ref remote_htlc_base_key, ref preimage, ref htlc } => {
 610                                                 if let Ok(chan_keys) = TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, remote_delayed_payment_base_key, remote_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
 611                                                         let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key);
 612
 613                                                         if !preimage.is_some() { bumped_tx.lock_time = 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
 614                                                         if let Ok(sig) = self.key_storage.sign_remote_htlc_transaction(&bumped_tx, i, &htlc.amount_msat / 1000, &per_commitment_point, htlc, &self.secp_ctx) {
 615                                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 616                                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 617                                                                 if let &Some(preimage) = preimage {
 618                                                                         bumped_tx.input[i].witness.push(preimage.0.to_vec());
 619                                                                 } else {
 620                                                                         // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
 621                                                                         bumped_tx.input[i].witness.push(vec![]);
 622                                                                 }
 623                                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 624                                                         }
 625                                                         log_trace!(logger, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);
 626                                                 }
 627                                         },
 628                                         _ => unreachable!()
 629                                 }
 630                         }
 631                         log_trace!(logger, "...with timer {}", new_timer.unwrap());
 632                         assert!(predicted_weight >= bumped_tx.get_weight() as u64);
 633                         return Some((new_timer, new_feerate as u32, bumped_tx))
 634                 } else {
 635                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 636                                 match per_outp_material {
 637                                         &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
 638                                                 let htlc_tx = self.get_fully_signed_htlc_tx(outp, preimage);
 639                                                 if let Some(htlc_tx) = htlc_tx {
 640                                                         let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
 641                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 642                                                         log_trace!(logger, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
 643                                                         return Some((None, feerate as u32, htlc_tx));
 644                                                 }
 645                                                 return None;
 646                                         },
 647                                         &InputMaterial::Funding { ref funding_redeemscript } => {
 648                                                 let signed_tx = self.get_fully_signed_local_tx(funding_redeemscript).unwrap();
 649                                                 // Timer set to $NEVER given we can't bump tx without anchor outputs
 650                                                 log_trace!(logger, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 651                                                 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
 652                                         }
 653                                         _ => unreachable!()
 654                                 }
 655                         }
 656                 }
 657                 None
 658         }
 659
 660         pub(super) fn block_connected<B: Deref, F: Deref, L: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<ClaimRequest>, height: u32, broadcaster: B, fee_estimator: F, logger: L)
 661                 where B::Target: BroadcasterInterface,
 662                       F::Target: FeeEstimator,
 663                                         L::Target: Logger,
 664         {
 665                 log_trace!(logger, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 666                 let mut new_claims = Vec::new();
 667                 let mut aggregated_claim = HashMap::new();
 668                 let mut aggregated_soonest = ::std::u32::MAX;
 669
 670                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 671                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 672                 for req in claimable_outpoints {
 673                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 674                         if let Some(_) = self.claimable_outpoints.get(&req.outpoint) { log_trace!(logger, "Bouncing off outpoint {}:{}, already registered its claiming request", req.outpoint.txid, req.outpoint.vout); } else {
 675                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 676                                 if req.absolute_timelock <= height + CLTV_SHARED_CLAIM_BUFFER || !req.aggregable { // Don't aggregate if outpoint absolute timelock is soon or marked as non-aggregable
 677                                         let mut single_input = HashMap::new();
 678                                         single_input.insert(req.outpoint, req.witness_data);
 679                                         new_claims.push((req.absolute_timelock, single_input));
 680                                 } else {
 681                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 682                                         if req.absolute_timelock < aggregated_soonest {
 683                                                 aggregated_soonest = req.absolute_timelock;
 684                                         }
 685                                 }
 686                         }
 687                 }
 688                 new_claims.push((aggregated_soonest, aggregated_claim));
 689
 690                 // Generate claim transactions and track them to bump if necessary at
 691                 // height timer expiration (i.e in how many blocks we're going to take action).
 692                 for (soonest_timelock, claim) in new_claims.drain(..) {
 693                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
 694                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 695                                 claim_material.height_timer = new_timer;
 696                                 claim_material.feerate_previous = new_feerate;
 697                                 let txid = tx.txid();
 698                                 for k in claim_material.per_input_material.keys() {
 699                                         log_trace!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 700                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 701                                 }
 702                                 self.pending_claim_requests.insert(txid, claim_material);
 703                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(tx));
 704                                 broadcaster.broadcast_transaction(&tx);
 705                         }
 706                 }
 707
 708                 let mut bump_candidates = HashMap::new();
 709                 for tx in txn_matched {
 710                         // Scan all input to verify is one of the outpoint spent is of interest for us
 711                         let mut claimed_outputs_material = Vec::new();
 712                         for inp in &tx.input {
 713                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 714                                         // If outpoint has claim request pending on it...
 715                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 716                                                 //... we need to verify equality between transaction outpoints and claim request
 717                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 718                                                 // by us.
 719                                                 let mut set_equality = true;
 720                                                 if claim_material.per_input_material.len() != tx.input.len() {
 721                                                         set_equality = false;
 722                                                 } else {
 723                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 724                                                                 if *claim_inp != tx_inp.previous_output {
 725                                                                         set_equality = false;
 726                                                                 }
 727                                                         }
 728                                                 }
 729
 730                                                 macro_rules! clean_claim_request_after_safety_delay {
 731                                                         () => {
 732                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 733                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 734                                                                         hash_map::Entry::Occupied(mut entry) => {
 735                                                                                 if !entry.get().contains(&new_event) {
 736                                                                                         entry.get_mut().push(new_event);
 737                                                                                 }
 738                                                                         },
 739                                                                         hash_map::Entry::Vacant(entry) => {
 740                                                                                 entry.insert(vec![new_event]);
 741                                                                         }
 742                                                                 }
 743                                                         }
 744                                                 }
 745
 746                                                 // If this is our transaction (or our counterparty spent all the outputs
 747                                                 // before we could anyway with same inputs order than us), wait for
 748                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 749                                                 if set_equality {
 750                                                         clean_claim_request_after_safety_delay!();
 751                                                 } else { // If false, generate new claim request with update outpoint set
 752                                                         let mut at_least_one_drop = false;
 753                                                         for input in tx.input.iter() {
 754                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 755                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 756                                                                         at_least_one_drop = true;
 757                                                                 }
 758                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 759                                                                 if claim_material.per_input_material.is_empty() {
 760                                                                         clean_claim_request_after_safety_delay!();
 761                                                                 }
 762                                                         }
 763                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 764                                                         if at_least_one_drop {
 765                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
 766                                                         }
 767                                                 }
 768                                                 break; //No need to iterate further, either tx is our or their
 769                                         } else {
 770                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 771                                         }
 772                                 }
 773                         }
 774                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 775                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 776                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 777                                         hash_map::Entry::Occupied(mut entry) => {
 778                                                 if !entry.get().contains(&new_event) {
 779                                                         entry.get_mut().push(new_event);
 780                                                 }
 781                                         },
 782                                         hash_map::Entry::Vacant(entry) => {
 783                                                 entry.insert(vec![new_event]);
 784                                         }
 785                                 }
 786                         }
 787                 }
 788
 789                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 790                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 791                         for ev in events {
 792                                 match ev {
 793                                         OnchainEvent::Claim { claim_request } => {
 794                                                 // We may remove a whole set of claim outpoints here, as these one may have
 795                                                 // been aggregated in a single tx and claimed so atomically
 796                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 797                                                         for outpoint in bump_material.per_input_material.keys() {
 798                                                                 self.claimable_outpoints.remove(&outpoint);
 799                                                         }
 800                                                 }
 801                                         },
 802                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 803                                                 self.claimable_outpoints.remove(&outpoint);
 804                                         }
 805                                 }
 806                         }
 807                 }
 808
 809                 // Check if any pending claim request must be rescheduled
 810                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 811                         if let Some(h) = claim_data.height_timer {
 812                                 if h == height {
 813                                         bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
 814                                 }
 815                         }
 816                 }
 817
 818                 // Build, bump and rebroadcast tx accordingly
 819                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 820                 for (first_claim_txid, claim_material) in bump_candidates.iter() {
 821                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 822                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(bump_tx));
 823                                 broadcaster.broadcast_transaction(&bump_tx);
 824                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 825                                         claim_material.height_timer = new_timer;
 826                                         claim_material.feerate_previous = new_feerate;
 827                                 }
 828                         }
 829                 }
 830         }
 831
 832         pub(super) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F, logger: L)
 833                 where B::Target: BroadcasterInterface,
 834                       F::Target: FeeEstimator,
 835                                         L::Target: Logger,
 836         {
 837                 let mut bump_candidates = HashMap::new();
 838                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 839                         //- our claim tx on a commitment tx output
 840                         //- resurect outpoint back in its claimable set and regenerate tx
 841                         for ev in events {
 842                                 match ev {
 843                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 844                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 845                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 846                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 847                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 848                                                                 // resurrected only one bump claim tx is going to be broadcast
 849                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 850                                                         }
 851                                                 }
 852                                         },
 853                                         _ => {},
 854                                 }
 855                         }
 856                 }
 857                 for (_, claim_material) in bump_candidates.iter_mut() {
 858                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 859                                 claim_material.height_timer = new_timer;
 860                                 claim_material.feerate_previous = new_feerate;
 861                                 broadcaster.broadcast_transaction(&bump_tx);
 862                         }
 863                 }
 864                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 865                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 866                 }
 867                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 868                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 869                 let mut remove_request = Vec::new();
 870                 self.claimable_outpoints.retain(|_, ref v|
 871                         if v.1 == height {
 872                         remove_request.push(v.0.clone());
 873                         false
 874                         } else { true });
 875                 for req in remove_request {
 876                         self.pending_claim_requests.remove(&req);
 877                 }
 878         }
 879
 880         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
 881                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 882                 // commitment transaction has been signed due to an event (either block height for
 883                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 884                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 885                 // for the aformentionned signed transaction.
 886                 if self.local_htlc_sigs.is_some() || self.prev_local_htlc_sigs.is_some() {
 887                         return Err(());
 888                 }
 889                 self.prev_local_commitment = self.local_commitment.take();
 890                 self.local_commitment = Some(tx);
 891                 Ok(())
 892         }
 893
 894         fn sign_latest_local_htlcs(&mut self) {
 895                 if let Some(ref local_commitment) = self.local_commitment {
 896                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, &self.secp_ctx) {
 897                                 self.local_htlc_sigs = Some(Vec::new());
 898                                 let ret = self.local_htlc_sigs.as_mut().unwrap();
 899                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 900                                         if let Some(tx_idx) = htlc.transaction_output_index {
 901                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 902                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 903                                         } else {
 904                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 905                                         }
 906                                 }
 907                         }
 908                 }
 909         }
 910         fn sign_prev_local_htlcs(&mut self) {
 911                 if let Some(ref local_commitment) = self.prev_local_commitment {
 912                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, &self.secp_ctx) {
 913                                 self.prev_local_htlc_sigs = Some(Vec::new());
 914                                 let ret = self.prev_local_htlc_sigs.as_mut().unwrap();
 915                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 916                                         if let Some(tx_idx) = htlc.transaction_output_index {
 917                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 918                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 919                                         } else {
 920                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 921                                         }
 922                                 }
 923                         }
 924                 }
 925         }
 926
 927         //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
 928         // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 929         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 930         // to monitor before.
 931         pub(super) fn get_fully_signed_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 932                 if let Some(ref mut local_commitment) = self.local_commitment {
 933                         match self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx) {
 934                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 935                                 Err(_) => return None,
 936                         }
 937                 } else {
 938                         None
 939                 }
 940         }
 941
 942         #[cfg(test)]
 943         pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 944                 if let Some(ref mut local_commitment) = self.local_commitment {
 945                         let local_commitment = local_commitment.clone();
 946                         match self.key_storage.sign_local_commitment(&local_commitment, &self.secp_ctx) {
 947                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 948                                 Err(_) => return None,
 949                         }
 950                 } else {
 951                         None
 952                 }
 953         }
 954
 955         pub(super) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 956                 let mut htlc_tx = None;
 957                 if self.local_commitment.is_some() {
 958                         let commitment_txid = self.local_commitment.as_ref().unwrap().txid();
 959                         if commitment_txid == outp.txid {
 960                                 self.sign_latest_local_htlcs();
 961                                 if let &Some(ref htlc_sigs) = &self.local_htlc_sigs {
 962                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 963                                         htlc_tx = Some(self.local_commitment.as_ref().unwrap()
 964                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.on_local_tx_csv));
 965                                 }
 966                         }
 967                 }
 968                 if self.prev_local_commitment.is_some() {
 969                         let commitment_txid = self.prev_local_commitment.as_ref().unwrap().txid();
 970                         if commitment_txid == outp.txid {
 971                                 self.sign_prev_local_htlcs();
 972                                 if let &Some(ref htlc_sigs) = &self.prev_local_htlc_sigs {
 973                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 974                                         htlc_tx = Some(self.prev_local_commitment.as_ref().unwrap()
 975                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.on_local_tx_csv));
 976                                 }
 977                         }
 978                 }
 979                 htlc_tx
 980         }
 981
 982         #[cfg(test)]
 983         pub(super) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 984                 let latest_had_sigs = self.local_htlc_sigs.is_some();
 985                 let prev_had_sigs = self.prev_local_htlc_sigs.is_some();
 986                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
 987                 if !latest_had_sigs {
 988                         self.local_htlc_sigs = None;
 989                 }
 990                 if !prev_had_sigs {
 991                         self.prev_local_htlc_sigs = None;
 992                 }
 993                 ret
 994         }
 995 }