_ Git - rust-lightning/blob - lightning/src/ln/onchaintx.rs

   1 //! The logic to build claims and bump in-flight transactions until confirmations.
   2 //!
   3 //! OnchainTxHandler objetcs are fully-part of ChannelMonitor and encapsulates all
   4 //! building, tracking, bumping and notifications functions.
   5
   6 use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
   7 use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
   8 use bitcoin::blockdata::script::Script;
   9
  10 use bitcoin::hash_types::Txid;
  11
  12 use bitcoin::secp256k1::{Secp256k1, Signature};
  13 use bitcoin::secp256k1;
  14
  15 use ln::msgs::DecodeError;
  16 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
  17 use ln::channelmanager::PaymentPreimage;
  18 use ln::chan_utils;
  19 use ln::chan_utils::{TxCreationKeys, LocalCommitmentTransaction};
  20 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
  21 use chain::keysinterface::ChannelKeys;
  22 use util::logger::Logger;
  23 use util::ser::{Readable, Writer, Writeable};
  24 use util::byte_utils;
  25
  26 use std::collections::{HashMap, hash_map};
  27 use std::cmp;
  28 use std::ops::Deref;
  29
  30 const MAX_ALLOC_SIZE: usize = 64*1024;
  31
  32 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
  33 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
  34 #[derive(Clone, PartialEq)]
  35 enum OnchainEvent {
  36         /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
  37         /// bump-txn candidate buffer.
  38         Claim {
  39                 claim_request: Txid,
  40         },
  41         /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
  42         /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
  43         /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
  44         ContentiousOutpoint {
  45                 outpoint: BitcoinOutPoint,
  46                 input_material: InputMaterial,
  47         }
  48 }
  49
  50 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
  51 #[derive(Clone, PartialEq)]
  52 pub struct ClaimTxBumpMaterial {
  53         // At every block tick, used to check if pending claiming tx is taking too
  54         // much time for confirmation and we need to bump it.
  55         height_timer: Option<u32>,
  56         // Tracked in case of reorg to wipe out now-superflous bump material
  57         feerate_previous: u64,
  58         // Soonest timelocks among set of outpoints claimed, used to compute
  59         // a priority of not feerate
  60         soonest_timelock: u32,
  61         // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
  62         per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
  63 }
  64
  65 impl Writeable for ClaimTxBumpMaterial  {
  66         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
  67                 self.height_timer.write(writer)?;
  68                 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
  69                 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
  70                 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
  71                 for (outp, tx_material) in self.per_input_material.iter() {
  72                         outp.write(writer)?;
  73                         tx_material.write(writer)?;
  74                 }
  75                 Ok(())
  76         }
  77 }
  78
  79 impl Readable for ClaimTxBumpMaterial {
  80         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
  81                 let height_timer = Readable::read(reader)?;
  82                 let feerate_previous = Readable::read(reader)?;
  83                 let soonest_timelock = Readable::read(reader)?;
  84                 let per_input_material_len: u64 = Readable::read(reader)?;
  85                 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
  86                 for _ in 0 ..per_input_material_len {
  87                         let outpoint = Readable::read(reader)?;
  88                         let input_material = Readable::read(reader)?;
  89                         per_input_material.insert(outpoint, input_material);
  90                 }
  91                 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
  92         }
  93 }
  94
  95 #[derive(PartialEq, Clone, Copy)]
  96 pub(crate) enum InputDescriptors {
  97         RevokedOfferedHTLC,
  98         RevokedReceivedHTLC,
  99         OfferedHTLC,
 100         ReceivedHTLC,
 101         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 102 }
 103
 104 impl Writeable for InputDescriptors {
 105         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 106                 match self {
 107                         &InputDescriptors::RevokedOfferedHTLC => {
 108                                 writer.write_all(&[0; 1])?;
 109                         },
 110                         &InputDescriptors::RevokedReceivedHTLC => {
 111                                 writer.write_all(&[1; 1])?;
 112                         },
 113                         &InputDescriptors::OfferedHTLC => {
 114                                 writer.write_all(&[2; 1])?;
 115                         },
 116                         &InputDescriptors::ReceivedHTLC => {
 117                                 writer.write_all(&[3; 1])?;
 118                         }
 119                         &InputDescriptors::RevokedOutput => {
 120                                 writer.write_all(&[4; 1])?;
 121                         }
 122                 }
 123                 Ok(())
 124         }
 125 }
 126
 127 impl Readable for InputDescriptors {
 128         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 129                 let input_descriptor = match <u8 as Readable>::read(reader)? {
 130                         0 => {
 131                                 InputDescriptors::RevokedOfferedHTLC
 132                         },
 133                         1 => {
 134                                 InputDescriptors::RevokedReceivedHTLC
 135                         },
 136                         2 => {
 137                                 InputDescriptors::OfferedHTLC
 138                         },
 139                         3 => {
 140                                 InputDescriptors::ReceivedHTLC
 141                         },
 142                         4 => {
 143                                 InputDescriptors::RevokedOutput
 144                         }
 145                         _ => return Err(DecodeError::InvalidValue),
 146                 };
 147                 Ok(input_descriptor)
 148         }
 149 }
 150
 151 macro_rules! subtract_high_prio_fee {
 152         ($logger: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 153                 {
 154                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
 155                         let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
 156                         if $value <= fee {
 157                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 158                                 fee = $used_feerate * ($predicted_weight as u64) / 1000;
 159                                 if $value <= fee {
 160                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 161                                         fee = $used_feerate * ($predicted_weight as u64) / 1000;
 162                                         if $value <= fee {
 163                                                 log_error!($logger, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 164                                                         fee, $value);
 165                                                 false
 166                                         } else {
 167                                                 log_warn!($logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 168                                                         $value);
 169                                                 $value -= fee;
 170                                                 true
 171                                         }
 172                                 } else {
 173                                         log_warn!($logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 174                                                 $value);
 175                                         $value -= fee;
 176                                         true
 177                                 }
 178                         } else {
 179                                 $value -= fee;
 180                                 true
 181                         }
 182                 }
 183         }
 184 }
 185
 186 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 187         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 188                 match Readable::read(reader)? {
 189                         0u8 => Ok(None),
 190                         1u8 => {
 191                                 let vlen: u64 = Readable::read(reader)?;
 192                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<Option<(usize, Signature)>>()));
 193                                 for _ in 0..vlen {
 194                                         ret.push(match Readable::read(reader)? {
 195                                                 0u8 => None,
 196                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 197                                                 _ => return Err(DecodeError::InvalidValue)
 198                                         });
 199                                 }
 200                                 Ok(Some(ret))
 201                         },
 202                         _ => Err(DecodeError::InvalidValue),
 203                 }
 204         }
 205 }
 206
 207 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 208         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 209                 match self {
 210                         &Some(ref vec) => {
 211                                 1u8.write(writer)?;
 212                                 (vec.len() as u64).write(writer)?;
 213                                 for opt in vec.iter() {
 214                                         match opt {
 215                                                 &Some((ref idx, ref sig)) => {
 216                                                         1u8.write(writer)?;
 217                                                         (*idx as u64).write(writer)?;
 218                                                         sig.write(writer)?;
 219                                                 },
 220                                                 &None => 0u8.write(writer)?,
 221                                         }
 222                                 }
 223                         },
 224                         &None => 0u8.write(writer)?,
 225                 }
 226                 Ok(())
 227         }
 228 }
 229
 230
 231 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 232 /// do RBF bumping if possible.
 233 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 234         destination_script: Script,
 235         local_commitment: Option<LocalCommitmentTransaction>,
 236         // local_htlc_sigs and prev_local_htlc_sigs are in the order as they appear in the commitment
 237         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 238         // the set of HTLCs in the LocalCommitmentTransaction (including those which do not appear in
 239         // the commitment transaction).
 240         local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 241         prev_local_commitment: Option<LocalCommitmentTransaction>,
 242         prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 243         local_csv: u16,
 244         remote_csv: u16,
 245
 246         key_storage: ChanSigner,
 247
 248         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 249         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 250         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 251         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 252         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 253         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 254         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 255         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 256         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 257         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 258         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 259         #[cfg(test)] // Used in functional_test to verify sanitization
 260         pub pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 261         #[cfg(not(test))]
 262         pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 263
 264         // Used to link outpoints claimed in a connected block to a pending claim request.
 265         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 266         // Value is (pending claim request identifier, confirmation_block), identifier
 267         // is txid of the initial claiming transaction and is immutable until outpoint is
 268         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 269         // block with output gets disconnected.
 270         #[cfg(test)] // Used in functional_test to verify sanitization
 271         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 272         #[cfg(not(test))]
 273         claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 274
 275         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 276
 277         secp_ctx: Secp256k1<secp256k1::All>,
 278 }
 279
 280 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 281         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 282                 self.destination_script.write(writer)?;
 283                 self.local_commitment.write(writer)?;
 284                 self.local_htlc_sigs.write(writer)?;
 285                 self.prev_local_commitment.write(writer)?;
 286                 self.prev_local_htlc_sigs.write(writer)?;
 287
 288                 self.local_csv.write(writer)?;
 289
 290                 self.remote_csv.write(writer)?;
 291
 292                 self.key_storage.write(writer)?;
 293
 294                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 295                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 296                         ancestor_claim_txid.write(writer)?;
 297                         claim_tx_data.write(writer)?;
 298                 }
 299
 300                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 301                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 302                         outp.write(writer)?;
 303                         claim_and_height.0.write(writer)?;
 304                         claim_and_height.1.write(writer)?;
 305                 }
 306
 307                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 308                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 309                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 310                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 311                         for ev in events.iter() {
 312                                 match *ev {
 313                                         OnchainEvent::Claim { ref claim_request } => {
 314                                                 writer.write_all(&[0; 1])?;
 315                                                 claim_request.write(writer)?;
 316                                         },
 317                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 318                                                 writer.write_all(&[1; 1])?;
 319                                                 outpoint.write(writer)?;
 320                                                 input_material.write(writer)?;
 321                                         }
 322                                 }
 323                         }
 324                 }
 325                 Ok(())
 326         }
 327 }
 328
 329 impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
 330         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 331                 let destination_script = Readable::read(reader)?;
 332
 333                 let local_commitment = Readable::read(reader)?;
 334                 let local_htlc_sigs = Readable::read(reader)?;
 335                 let prev_local_commitment = Readable::read(reader)?;
 336                 let prev_local_htlc_sigs = Readable::read(reader)?;
 337
 338                 let local_csv = Readable::read(reader)?;
 339
 340                 let remote_csv = Readable::read(reader)?;
 341
 342                 let key_storage = Readable::read(reader)?;
 343
 344                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 345                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 346                 for _ in 0..pending_claim_requests_len {
 347                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 348                 }
 349
 350                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 351                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 352                 for _ in 0..claimable_outpoints_len {
 353                         let outpoint = Readable::read(reader)?;
 354                         let ancestor_claim_txid = Readable::read(reader)?;
 355                         let height = Readable::read(reader)?;
 356                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 357                 }
 358                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 359                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 360                 for _ in 0..waiting_threshold_conf_len {
 361                         let height_target = Readable::read(reader)?;
 362                         let events_len: u64 = Readable::read(reader)?;
 363                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 364                         for _ in 0..events_len {
 365                                 let ev = match <u8 as Readable>::read(reader)? {
 366                                         0 => {
 367                                                 let claim_request = Readable::read(reader)?;
 368                                                 OnchainEvent::Claim {
 369                                                         claim_request
 370                                                 }
 371                                         },
 372                                         1 => {
 373                                                 let outpoint = Readable::read(reader)?;
 374                                                 let input_material = Readable::read(reader)?;
 375                                                 OnchainEvent::ContentiousOutpoint {
 376                                                         outpoint,
 377                                                         input_material
 378                                                 }
 379                                         }
 380                                         _ => return Err(DecodeError::InvalidValue),
 381                                 };
 382                                 events.push(ev);
 383                         }
 384                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 385                 }
 386
 387                 Ok(OnchainTxHandler {
 388                         destination_script,
 389                         local_commitment,
 390                         local_htlc_sigs,
 391                         prev_local_commitment,
 392                         prev_local_htlc_sigs,
 393                         local_csv,
 394                         remote_csv,
 395                         key_storage,
 396                         claimable_outpoints,
 397                         pending_claim_requests,
 398                         onchain_events_waiting_threshold_conf,
 399                         secp_ctx: Secp256k1::new(),
 400                 })
 401         }
 402 }
 403
 404 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 405         pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16, remote_csv: u16) -> Self {
 406
 407                 let key_storage = keys;
 408
 409                 OnchainTxHandler {
 410                         destination_script,
 411                         local_commitment: None,
 412                         local_htlc_sigs: None,
 413                         prev_local_commitment: None,
 414                         prev_local_htlc_sigs: None,
 415                         local_csv,
 416                         remote_csv,
 417                         key_storage,
 418                         pending_claim_requests: HashMap::new(),
 419                         claimable_outpoints: HashMap::new(),
 420                         onchain_events_waiting_threshold_conf: HashMap::new(),
 421
 422                         secp_ctx: Secp256k1::new(),
 423                 }
 424         }
 425
 426         pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
 427                 let mut tx_weight = 2; // count segwit flags
 428                 for inp in inputs {
 429                         // We use expected weight (and not actual) as signatures and time lock delays may vary
 430                         tx_weight +=  match inp {
 431                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 432                                 &InputDescriptors::RevokedOfferedHTLC => {
 433                                         1 + 1 + 73 + 1 + 33 + 1 + 133
 434                                 },
 435                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 436                                 &InputDescriptors::RevokedReceivedHTLC => {
 437                                         1 + 1 + 73 + 1 + 33 + 1 + 139
 438                                 },
 439                                 // number_of_witness_elements + sig_length + remotehtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
 440                                 &InputDescriptors::OfferedHTLC => {
 441                                         1 + 1 + 73 + 1 + 32 + 1 + 133
 442                                 },
 443                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 444                                 &InputDescriptors::ReceivedHTLC => {
 445                                         1 + 1 + 73 + 1 + 1 + 1 + 139
 446                                 },
 447                                 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
 448                                 &InputDescriptors::RevokedOutput => {
 449                                         1 + 1 + 73 + 1 + 1 + 1 + 77
 450                                 },
 451                         };
 452                 }
 453                 tx_weight
 454         }
 455
 456         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 457         /// 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
 458         /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
 459         /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
 460         /// frequency of the bump and so increase our bets of success.
 461         fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
 462                 if timelock_expiration <= current_height + 3 {
 463                         return current_height + 1
 464                 } else if timelock_expiration - current_height <= 15 {
 465                         return current_height + 3
 466                 }
 467                 current_height + 15
 468         }
 469
 470         /// 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
 471         /// (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.
 472         fn generate_claim_tx<F: Deref, L: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F, logger: L) -> Option<(Option<u32>, u64, Transaction)>
 473                 where F::Target: FeeEstimator,
 474                                         L::Target: Logger,
 475         {
 476                 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
 477                 let mut inputs = Vec::new();
 478                 for outp in cached_claim_datas.per_input_material.keys() {
 479                         log_trace!(logger, "Outpoint {}:{}", outp.txid, outp.vout);
 480                         inputs.push(TxIn {
 481                                 previous_output: *outp,
 482                                 script_sig: Script::new(),
 483                                 sequence: 0xfffffffd,
 484                                 witness: Vec::new(),
 485                         });
 486                 }
 487                 let mut bumped_tx = Transaction {
 488                         version: 2,
 489                         lock_time: 0,
 490                         input: inputs,
 491                         output: vec![TxOut {
 492                                 script_pubkey: self.destination_script.clone(),
 493                                 value: 0
 494                         }],
 495                 };
 496
 497                 macro_rules! RBF_bump {
 498                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 499                                 {
 500                                         let mut used_feerate;
 501                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 502                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 503                                                 let mut value = $amount;
 504                                                 if subtract_high_prio_fee!(logger, $fee_estimator, value, $predicted_weight, used_feerate) {
 505                                                         // Overflow check is done in subtract_high_prio_fee
 506                                                         $amount - value
 507                                                 } else {
 508                                                         log_trace!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 509                                                         return None;
 510                                                 }
 511                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 512                                         } else {
 513                                                 let fee = $old_feerate * $predicted_weight / 750;
 514                                                 if $amount <= fee {
 515                                                         log_trace!(logger, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 516                                                         return None;
 517                                                 }
 518                                                 fee
 519                                         };
 520
 521                                         let previous_fee = $old_feerate * $predicted_weight / 1000;
 522                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
 523                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 524                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 525                                         //      * 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.
 526                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 527                                                 new_fee + previous_fee + min_relay_fee - new_fee
 528                                         } else {
 529                                                 new_fee
 530                                         };
 531                                         Some((new_fee, new_fee * 1000 / $predicted_weight))
 532                                 }
 533                         }
 534                 }
 535
 536                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 537                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 538                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 539                 let mut inputs_witnesses_weight = 0;
 540                 let mut amt = 0;
 541                 let mut dynamic_fee = true;
 542                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 543                         match per_outp_material {
 544                                 &InputMaterial::Revoked { ref input_descriptor, ref amount, .. } => {
 545                                         inputs_witnesses_weight += Self::get_witnesses_weight(&[*input_descriptor]);
 546                                         amt += *amount;
 547                                 },
 548                                 &InputMaterial::RemoteHTLC { ref preimage, ref htlc, .. } => {
 549                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 550                                         amt += htlc.amount_msat / 1000;
 551                                 },
 552                                 &InputMaterial::LocalHTLC { .. } => {
 553                                         dynamic_fee = false;
 554                                 },
 555                                 &InputMaterial::Funding { .. } => {
 556                                         dynamic_fee = false;
 557                                 }
 558                         }
 559                 }
 560                 if dynamic_fee {
 561                         let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
 562                         let mut new_feerate;
 563                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 564                         if cached_claim_datas.feerate_previous != 0 {
 565                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
 566                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 567                                         if new_fee > amt {
 568                                                 bumped_tx.output[0].value = 0;
 569                                         } else {
 570                                                 bumped_tx.output[0].value = amt - new_fee;
 571                                         }
 572                                         new_feerate = feerate;
 573                                 } else { return None; }
 574                         } else {
 575                                 if subtract_high_prio_fee!(logger, fee_estimator, amt, predicted_weight, new_feerate) {
 576                                         bumped_tx.output[0].value = amt;
 577                                 } else { return None; }
 578                         }
 579                         assert!(new_feerate != 0);
 580
 581                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 582                                 match per_outp_material {
 583                                         &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 } => {
 584                                                 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) {
 585
 586                                                         let witness_script = if let Some(ref htlc) = *htlc {
 587                                                                 chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key)
 588                                                         } else {
 589                                                                 chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, self.remote_csv, &chan_keys.a_delayed_payment_key)
 590                                                         };
 591
 592                                                         if let Ok(sig) = self.key_storage.sign_justice_transaction(&bumped_tx, i, &witness_script, *amount, &per_commitment_key, &chan_keys.revocation_key, htlc.is_some(),  &self.secp_ctx) {
 593                                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 594                                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 595                                                                 if htlc.is_some() {
 596                                                                         bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
 597                                                                 } else {
 598                                                                         bumped_tx.input[i].witness.push(vec!(1));
 599                                                                 }
 600                                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 601                                                         } else { return None; }
 602                                                         //TODO: panic ?
 603
 604                                                         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);
 605                                                 }
 606                                         },
 607                                         &InputMaterial::RemoteHTLC { ref per_commitment_point, ref remote_delayed_payment_base_key, ref remote_htlc_base_key, ref preimage, ref htlc } => {
 608                                                 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) {
 609                                                         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);
 610
 611                                                         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
 612                                                         if let Ok(sig) = self.key_storage.sign_remote_htlc_transaction(&bumped_tx, i, &witness_script, htlc.amount_msat / 1000, &per_commitment_point, preimage, &self.secp_ctx) {
 613                                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 614                                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 615                                                                 if let &Some(preimage) = preimage {
 616                                                                         bumped_tx.input[i].witness.push(preimage.0.to_vec());
 617                                                                 } else {
 618                                                                         // Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
 619                                                                         bumped_tx.input[i].witness.push(vec![]);
 620                                                                 }
 621                                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 622                                                         }
 623                                                         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);
 624                                                 }
 625                                         },
 626                                         _ => unreachable!()
 627                                 }
 628                         }
 629                         log_trace!(logger, "...with timer {}", new_timer.unwrap());
 630                         assert!(predicted_weight >= bumped_tx.get_weight());
 631                         return Some((new_timer, new_feerate, bumped_tx))
 632                 } else {
 633                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 634                                 match per_outp_material {
 635                                         &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
 636                                                 let htlc_tx = self.get_fully_signed_htlc_tx(outp, preimage);
 637                                                 if let Some(htlc_tx) = htlc_tx {
 638                                                         let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
 639                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 640                                                         log_trace!(logger, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
 641                                                         return Some((None, feerate, htlc_tx));
 642                                                 }
 643                                                 return None;
 644                                         },
 645                                         &InputMaterial::Funding { ref funding_redeemscript } => {
 646                                                 let signed_tx = self.get_fully_signed_local_tx(funding_redeemscript).unwrap();
 647                                                 // Timer set to $NEVER given we can't bump tx without anchor outputs
 648                                                 log_trace!(logger, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 649                                                 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
 650                                         }
 651                                         _ => unreachable!()
 652                                 }
 653                         }
 654                 }
 655                 None
 656         }
 657
 658         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)
 659                 where B::Target: BroadcasterInterface,
 660                       F::Target: FeeEstimator,
 661                                         L::Target: Logger,
 662         {
 663                 log_trace!(logger, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 664                 let mut new_claims = Vec::new();
 665                 let mut aggregated_claim = HashMap::new();
 666                 let mut aggregated_soonest = ::std::u32::MAX;
 667
 668                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 669                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 670                 for req in claimable_outpoints {
 671                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 672                         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 {
 673                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 674                                 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
 675                                         let mut single_input = HashMap::new();
 676                                         single_input.insert(req.outpoint, req.witness_data);
 677                                         new_claims.push((req.absolute_timelock, single_input));
 678                                 } else {
 679                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 680                                         if req.absolute_timelock < aggregated_soonest {
 681                                                 aggregated_soonest = req.absolute_timelock;
 682                                         }
 683                                 }
 684                         }
 685                 }
 686                 new_claims.push((aggregated_soonest, aggregated_claim));
 687
 688                 // Generate claim transactions and track them to bump if necessary at
 689                 // height timer expiration (i.e in how many blocks we're going to take action).
 690                 for (soonest_timelock, claim) in new_claims.drain(..) {
 691                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
 692                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 693                                 claim_material.height_timer = new_timer;
 694                                 claim_material.feerate_previous = new_feerate;
 695                                 let txid = tx.txid();
 696                                 for k in claim_material.per_input_material.keys() {
 697                                         log_trace!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 698                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 699                                 }
 700                                 self.pending_claim_requests.insert(txid, claim_material);
 701                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(tx));
 702                                 broadcaster.broadcast_transaction(&tx);
 703                         }
 704                 }
 705
 706                 let mut bump_candidates = HashMap::new();
 707                 for tx in txn_matched {
 708                         // Scan all input to verify is one of the outpoint spent is of interest for us
 709                         let mut claimed_outputs_material = Vec::new();
 710                         for inp in &tx.input {
 711                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 712                                         // If outpoint has claim request pending on it...
 713                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 714                                                 //... we need to verify equality between transaction outpoints and claim request
 715                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 716                                                 // by us.
 717                                                 let mut set_equality = true;
 718                                                 if claim_material.per_input_material.len() != tx.input.len() {
 719                                                         set_equality = false;
 720                                                 } else {
 721                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 722                                                                 if *claim_inp != tx_inp.previous_output {
 723                                                                         set_equality = false;
 724                                                                 }
 725                                                         }
 726                                                 }
 727
 728                                                 macro_rules! clean_claim_request_after_safety_delay {
 729                                                         () => {
 730                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 731                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 732                                                                         hash_map::Entry::Occupied(mut entry) => {
 733                                                                                 if !entry.get().contains(&new_event) {
 734                                                                                         entry.get_mut().push(new_event);
 735                                                                                 }
 736                                                                         },
 737                                                                         hash_map::Entry::Vacant(entry) => {
 738                                                                                 entry.insert(vec![new_event]);
 739                                                                         }
 740                                                                 }
 741                                                         }
 742                                                 }
 743
 744                                                 // If this is our transaction (or our counterparty spent all the outputs
 745                                                 // before we could anyway with same inputs order than us), wait for
 746                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 747                                                 if set_equality {
 748                                                         clean_claim_request_after_safety_delay!();
 749                                                 } else { // If false, generate new claim request with update outpoint set
 750                                                         let mut at_least_one_drop = false;
 751                                                         for input in tx.input.iter() {
 752                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 753                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 754                                                                         at_least_one_drop = true;
 755                                                                 }
 756                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 757                                                                 if claim_material.per_input_material.is_empty() {
 758                                                                         clean_claim_request_after_safety_delay!();
 759                                                                 }
 760                                                         }
 761                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 762                                                         if at_least_one_drop {
 763                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
 764                                                         }
 765                                                 }
 766                                                 break; //No need to iterate further, either tx is our or their
 767                                         } else {
 768                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 769                                         }
 770                                 }
 771                         }
 772                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 773                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 774                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 775                                         hash_map::Entry::Occupied(mut entry) => {
 776                                                 if !entry.get().contains(&new_event) {
 777                                                         entry.get_mut().push(new_event);
 778                                                 }
 779                                         },
 780                                         hash_map::Entry::Vacant(entry) => {
 781                                                 entry.insert(vec![new_event]);
 782                                         }
 783                                 }
 784                         }
 785                 }
 786
 787                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 788                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 789                         for ev in events {
 790                                 match ev {
 791                                         OnchainEvent::Claim { claim_request } => {
 792                                                 // We may remove a whole set of claim outpoints here, as these one may have
 793                                                 // been aggregated in a single tx and claimed so atomically
 794                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 795                                                         for outpoint in bump_material.per_input_material.keys() {
 796                                                                 self.claimable_outpoints.remove(&outpoint);
 797                                                         }
 798                                                 }
 799                                         },
 800                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 801                                                 self.claimable_outpoints.remove(&outpoint);
 802                                         }
 803                                 }
 804                         }
 805                 }
 806
 807                 // Check if any pending claim request must be rescheduled
 808                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 809                         if let Some(h) = claim_data.height_timer {
 810                                 if h == height {
 811                                         bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
 812                                 }
 813                         }
 814                 }
 815
 816                 // Build, bump and rebroadcast tx accordingly
 817                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 818                 for (first_claim_txid, claim_material) in bump_candidates.iter() {
 819                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 820                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(bump_tx));
 821                                 broadcaster.broadcast_transaction(&bump_tx);
 822                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 823                                         claim_material.height_timer = new_timer;
 824                                         claim_material.feerate_previous = new_feerate;
 825                                 }
 826                         }
 827                 }
 828         }
 829
 830         pub(super) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F, logger: L)
 831                 where B::Target: BroadcasterInterface,
 832                       F::Target: FeeEstimator,
 833                                         L::Target: Logger,
 834         {
 835                 let mut bump_candidates = HashMap::new();
 836                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 837                         //- our claim tx on a commitment tx output
 838                         //- resurect outpoint back in its claimable set and regenerate tx
 839                         for ev in events {
 840                                 match ev {
 841                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 842                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 843                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 844                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 845                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 846                                                                 // resurrected only one bump claim tx is going to be broadcast
 847                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 848                                                         }
 849                                                 }
 850                                         },
 851                                         _ => {},
 852                                 }
 853                         }
 854                 }
 855                 for (_, claim_material) in bump_candidates.iter_mut() {
 856                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 857                                 claim_material.height_timer = new_timer;
 858                                 claim_material.feerate_previous = new_feerate;
 859                                 broadcaster.broadcast_transaction(&bump_tx);
 860                         }
 861                 }
 862                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 863                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 864                 }
 865                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 866                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 867                 let mut remove_request = Vec::new();
 868                 self.claimable_outpoints.retain(|_, ref v|
 869                         if v.1 == height {
 870                         remove_request.push(v.0.clone());
 871                         false
 872                         } else { true });
 873                 for req in remove_request {
 874                         self.pending_claim_requests.remove(&req);
 875                 }
 876         }
 877
 878         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
 879                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 880                 // commitment transaction has been signed due to an event (either block height for
 881                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 882                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 883                 // for the aformentionned signed transaction.
 884                 if self.local_htlc_sigs.is_some() || self.prev_local_htlc_sigs.is_some() {
 885                         return Err(());
 886                 }
 887                 self.prev_local_commitment = self.local_commitment.take();
 888                 self.local_commitment = Some(tx);
 889                 Ok(())
 890         }
 891
 892         fn sign_latest_local_htlcs(&mut self) {
 893                 if let Some(ref local_commitment) = self.local_commitment {
 894                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 895                                 self.local_htlc_sigs = Some(Vec::new());
 896                                 let ret = self.local_htlc_sigs.as_mut().unwrap();
 897                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 898                                         if let Some(tx_idx) = htlc.transaction_output_index {
 899                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 900                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 901                                         } else {
 902                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 903                                         }
 904                                 }
 905                         }
 906                 }
 907         }
 908         fn sign_prev_local_htlcs(&mut self) {
 909                 if let Some(ref local_commitment) = self.prev_local_commitment {
 910                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 911                                 self.prev_local_htlc_sigs = Some(Vec::new());
 912                                 let ret = self.prev_local_htlc_sigs.as_mut().unwrap();
 913                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 914                                         if let Some(tx_idx) = htlc.transaction_output_index {
 915                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 916                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 917                                         } else {
 918                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 919                                         }
 920                                 }
 921                         }
 922                 }
 923         }
 924
 925         //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
 926         // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 927         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 928         // to monitor before.
 929         pub(super) fn get_fully_signed_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 930                 if let Some(ref mut local_commitment) = self.local_commitment {
 931                         match self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx) {
 932                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 933                                 Err(_) => return None,
 934                         }
 935                 } else {
 936                         None
 937                 }
 938         }
 939
 940         #[cfg(test)]
 941         pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 942                 if let Some(ref mut local_commitment) = self.local_commitment {
 943                         let local_commitment = local_commitment.clone();
 944                         match self.key_storage.sign_local_commitment(&local_commitment, &self.secp_ctx) {
 945                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 946                                 Err(_) => return None,
 947                         }
 948                 } else {
 949                         None
 950                 }
 951         }
 952
 953         pub(super) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 954                 let mut htlc_tx = None;
 955                 if self.local_commitment.is_some() {
 956                         let commitment_txid = self.local_commitment.as_ref().unwrap().txid();
 957                         if commitment_txid == outp.txid {
 958                                 self.sign_latest_local_htlcs();
 959                                 if let &Some(ref htlc_sigs) = &self.local_htlc_sigs {
 960                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 961                                         htlc_tx = Some(self.local_commitment.as_ref().unwrap()
 962                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
 963                                 }
 964                         }
 965                 }
 966                 if self.prev_local_commitment.is_some() {
 967                         let commitment_txid = self.prev_local_commitment.as_ref().unwrap().txid();
 968                         if commitment_txid == outp.txid {
 969                                 self.sign_prev_local_htlcs();
 970                                 if let &Some(ref htlc_sigs) = &self.prev_local_htlc_sigs {
 971                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 972                                         htlc_tx = Some(self.prev_local_commitment.as_ref().unwrap()
 973                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
 974                                 }
 975                         }
 976                 }
 977                 htlc_tx
 978         }
 979
 980         #[cfg(test)]
 981         pub(super) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 982                 let latest_had_sigs = self.local_htlc_sigs.is_some();
 983                 let prev_had_sigs = self.prev_local_htlc_sigs.is_some();
 984                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
 985                 if !latest_had_sigs {
 986                         self.local_htlc_sigs = None;
 987                 }
 988                 if !prev_had_sigs {
 989                         self.prev_local_htlc_sigs = None;
 990                 }
 991                 ret
 992         }
 993 }