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