_ 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 use bitcoin::util::bip143;
  10
  11 use bitcoin::hash_types::Txid;
  12
  13 use bitcoin::secp256k1::{Secp256k1, Signature};
  14 use bitcoin::secp256k1;
  15 use bitcoin::secp256k1::key::PublicKey;
  16
  17 use ln::msgs::DecodeError;
  18 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
  19 use ln::channelmanager::PaymentPreimage;
  20 use ln::chan_utils::{HTLCType, LocalCommitmentTransaction, HTLCOutputInCommitment};
  21 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
  22 use chain::keysinterface::ChannelKeys;
  23 use util::logger::Logger;
  24 use util::ser::{Readable, Writer, Writeable};
  25 use util::byte_utils;
  26
  27 use std::collections::{HashMap, hash_map};
  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 /// Cache remote basepoint to compute any transaction on
  52 /// remote outputs, either justice or preimage/timeout transactions.
  53 struct RemoteTxCache {
  54         remote_delayed_payment_base_key: PublicKey,
  55         remote_htlc_base_key: PublicKey,
  56         per_htlc: HashMap<Sha256dHash, Vec<(HTLCOutputInCommitment)>>
  57 }
  58
  59 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
  60 #[derive(Clone, PartialEq)]
  61 pub struct ClaimTxBumpMaterial {
  62         // At every block tick, used to check if pending claiming tx is taking too
  63         // much time for confirmation and we need to bump it.
  64         height_timer: Option<u32>,
  65         // Tracked in case of reorg to wipe out now-superflous bump material
  66         feerate_previous: u64,
  67         // Soonest timelocks among set of outpoints claimed, used to compute
  68         // a priority of not feerate
  69         soonest_timelock: u32,
  70         // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
  71         per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
  72 }
  73
  74 impl Writeable for ClaimTxBumpMaterial  {
  75         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
  76                 self.height_timer.write(writer)?;
  77                 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
  78                 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
  79                 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
  80                 for (outp, tx_material) in self.per_input_material.iter() {
  81                         outp.write(writer)?;
  82                         tx_material.write(writer)?;
  83                 }
  84                 Ok(())
  85         }
  86 }
  87
  88 impl Readable for ClaimTxBumpMaterial {
  89         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
  90                 let height_timer = Readable::read(reader)?;
  91                 let feerate_previous = Readable::read(reader)?;
  92                 let soonest_timelock = Readable::read(reader)?;
  93                 let per_input_material_len: u64 = Readable::read(reader)?;
  94                 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
  95                 for _ in 0 ..per_input_material_len {
  96                         let outpoint = Readable::read(reader)?;
  97                         let input_material = Readable::read(reader)?;
  98                         per_input_material.insert(outpoint, input_material);
  99                 }
 100                 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
 101         }
 102 }
 103
 104 #[derive(PartialEq)]
 105 pub(super) enum InputDescriptors {
 106         RevokedOfferedHTLC,
 107         RevokedReceivedHTLC,
 108         OfferedHTLC,
 109         ReceivedHTLC,
 110         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 111 }
 112
 113 macro_rules! subtract_high_prio_fee {
 114         ($logger: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 115                 {
 116                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
 117                         let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
 118                         if $value <= fee {
 119                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 120                                 fee = $used_feerate * ($predicted_weight as u64) / 1000;
 121                                 if $value <= fee {
 122                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 123                                         fee = $used_feerate * ($predicted_weight as u64) / 1000;
 124                                         if $value <= fee {
 125                                                 log_error!($logger, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 126                                                         fee, $value);
 127                                                 false
 128                                         } else {
 129                                                 log_warn!($logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 130                                                         $value);
 131                                                 $value -= fee;
 132                                                 true
 133                                         }
 134                                 } else {
 135                                         log_warn!($logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 136                                                 $value);
 137                                         $value -= fee;
 138                                         true
 139                                 }
 140                         } else {
 141                                 $value -= fee;
 142                                 true
 143                         }
 144                 }
 145         }
 146 }
 147
 148 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 149         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 150                 match Readable::read(reader)? {
 151                         0u8 => Ok(None),
 152                         1u8 => {
 153                                 let vlen: u64 = Readable::read(reader)?;
 154                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<Option<(usize, Signature)>>()));
 155                                 for _ in 0..vlen {
 156                                         ret.push(match Readable::read(reader)? {
 157                                                 0u8 => None,
 158                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 159                                                 _ => return Err(DecodeError::InvalidValue)
 160                                         });
 161                                 }
 162                                 Ok(Some(ret))
 163                         },
 164                         _ => Err(DecodeError::InvalidValue),
 165                 }
 166         }
 167 }
 168
 169 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 170         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 171                 match self {
 172                         &Some(ref vec) => {
 173                                 1u8.write(writer)?;
 174                                 (vec.len() as u64).write(writer)?;
 175                                 for opt in vec.iter() {
 176                                         match opt {
 177                                                 &Some((ref idx, ref sig)) => {
 178                                                         1u8.write(writer)?;
 179                                                         (*idx as u64).write(writer)?;
 180                                                         sig.write(writer)?;
 181                                                 },
 182                                                 &None => 0u8.write(writer)?,
 183                                         }
 184                                 }
 185                         },
 186                         &None => 0u8.write(writer)?,
 187                 }
 188                 Ok(())
 189         }
 190 }
 191
 192
 193 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 194 /// do RBF bumping if possible.
 195 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 196         destination_script: Script,
 197         local_commitment: Option<LocalCommitmentTransaction>,
 198         // local_htlc_sigs and prev_local_htlc_sigs are in the order as they appear in the commitment
 199         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 200         // the set of HTLCs in the LocalCommitmentTransaction (including those which do not appear in
 201         // the commitment transaction).
 202         local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 203         prev_local_commitment: Option<LocalCommitmentTransaction>,
 204         prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 205         local_csv: u16,
 206         remote_tx_cache: RemoteTxCache,
 207         remote_csv: u16,
 208
 209         key_storage: ChanSigner,
 210
 211         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 212         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 213         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 214         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 215         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 216         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 217         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 218         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 219         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 220         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 221         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 222         #[cfg(test)] // Used in functional_test to verify sanitization
 223         pub pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 224         #[cfg(not(test))]
 225         pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 226
 227         // Used to link outpoints claimed in a connected block to a pending claim request.
 228         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 229         // Value is (pending claim request identifier, confirmation_block), identifier
 230         // is txid of the initial claiming transaction and is immutable until outpoint is
 231         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 232         // block with output gets disconnected.
 233         #[cfg(test)] // Used in functional_test to verify sanitization
 234         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 235         #[cfg(not(test))]
 236         claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 237
 238         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 239
 240         secp_ctx: Secp256k1<secp256k1::All>,
 241 }
 242
 243 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 244         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 245                 self.destination_script.write(writer)?;
 246                 self.local_commitment.write(writer)?;
 247                 self.local_htlc_sigs.write(writer)?;
 248                 self.prev_local_commitment.write(writer)?;
 249                 self.prev_local_htlc_sigs.write(writer)?;
 250
 251                 self.local_csv.write(writer)?;
 252
 253                 self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
 254                 self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
 255                 writer.write_all(&byte_utils::be64_to_array(self.remote_tx_cache.per_htlc.len() as u64))?;
 256                 for (ref txid, ref htlcs) in self.remote_tx_cache.per_htlc.iter() {
 257                         writer.write_all(&txid[..])?;
 258                         writer.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
 259                         for &ref htlc in htlcs.iter() {
 260                                 htlc.write(writer)?;
 261                         }
 262                 }
 263                 self.remote_csv.write(writer)?;
 264
 265                 self.key_storage.write(writer)?;
 266
 267                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 268                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 269                         ancestor_claim_txid.write(writer)?;
 270                         claim_tx_data.write(writer)?;
 271                 }
 272
 273                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 274                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 275                         outp.write(writer)?;
 276                         claim_and_height.0.write(writer)?;
 277                         claim_and_height.1.write(writer)?;
 278                 }
 279
 280                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 281                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 282                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 283                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 284                         for ev in events.iter() {
 285                                 match *ev {
 286                                         OnchainEvent::Claim { ref claim_request } => {
 287                                                 writer.write_all(&[0; 1])?;
 288                                                 claim_request.write(writer)?;
 289                                         },
 290                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 291                                                 writer.write_all(&[1; 1])?;
 292                                                 outpoint.write(writer)?;
 293                                                 input_material.write(writer)?;
 294                                         }
 295                                 }
 296                         }
 297                 }
 298                 Ok(())
 299         }
 300 }
 301
 302 impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
 303         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 304                 let destination_script = Readable::read(reader)?;
 305
 306                 let local_commitment = Readable::read(reader)?;
 307                 let local_htlc_sigs = Readable::read(reader)?;
 308                 let prev_local_commitment = Readable::read(reader)?;
 309                 let prev_local_htlc_sigs = Readable::read(reader)?;
 310
 311                 let local_csv = Readable::read(reader)?;
 312
 313                 let remote_tx_cache = {
 314                         let remote_delayed_payment_base_key = Readable::read(reader)?;
 315                         let remote_htlc_base_key = Readable::read(reader)?;
 316                         let per_htlc_len: u64 = Readable::read(reader)?;
 317                         let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
 318                         for _  in 0..per_htlc_len {
 319                                 let txid: Sha256dHash = Readable::read(reader)?;
 320                                 let htlcs_count: u64 = Readable::read(reader)?;
 321                                 let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
 322                                 for _ in 0..htlcs_count {
 323                                         let htlc = Readable::read(reader)?;
 324                                         htlcs.push(htlc);
 325                                 }
 326                                 if let Some(_) = per_htlc.insert(txid, htlcs) {
 327                                         return Err(DecodeError::InvalidValue);
 328                                 }
 329                         }
 330                         RemoteTxCache {
 331                                 remote_delayed_payment_base_key,
 332                                 remote_htlc_base_key,
 333                                 per_htlc,
 334                         }
 335                 };
 336                 let remote_csv = Readable::read(reader)?;
 337
 338                 let key_storage = Readable::read(reader)?;
 339
 340                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 341                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 342                 for _ in 0..pending_claim_requests_len {
 343                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 344                 }
 345
 346                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 347                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 348                 for _ in 0..claimable_outpoints_len {
 349                         let outpoint = Readable::read(reader)?;
 350                         let ancestor_claim_txid = Readable::read(reader)?;
 351                         let height = Readable::read(reader)?;
 352                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 353                 }
 354                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 355                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 356                 for _ in 0..waiting_threshold_conf_len {
 357                         let height_target = Readable::read(reader)?;
 358                         let events_len: u64 = Readable::read(reader)?;
 359                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 360                         for _ in 0..events_len {
 361                                 let ev = match <u8 as Readable>::read(reader)? {
 362                                         0 => {
 363                                                 let claim_request = Readable::read(reader)?;
 364                                                 OnchainEvent::Claim {
 365                                                         claim_request
 366                                                 }
 367                                         },
 368                                         1 => {
 369                                                 let outpoint = Readable::read(reader)?;
 370                                                 let input_material = Readable::read(reader)?;
 371                                                 OnchainEvent::ContentiousOutpoint {
 372                                                         outpoint,
 373                                                         input_material
 374                                                 }
 375                                         }
 376                                         _ => return Err(DecodeError::InvalidValue),
 377                                 };
 378                                 events.push(ev);
 379                         }
 380                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 381                 }
 382
 383                 Ok(OnchainTxHandler {
 384                         destination_script,
 385                         local_commitment,
 386                         local_htlc_sigs,
 387                         prev_local_commitment,
 388                         prev_local_htlc_sigs,
 389                         local_csv,
 390                         remote_tx_cache,
 391                         remote_csv,
 392                         key_storage,
 393                         claimable_outpoints,
 394                         pending_claim_requests,
 395                         onchain_events_waiting_threshold_conf,
 396                         secp_ctx: Secp256k1::new(),
 397                 })
 398         }
 399 }
 400
 401 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 402         pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16, remote_delayed_payment_base_key: PublicKey, remote_htlc_base_key: PublicKey, remote_csv: u16) -> Self {
 403
 404                 let key_storage = keys;
 405
 406                 let remote_tx_cache = RemoteTxCache {
 407                         remote_delayed_payment_base_key,
 408                         remote_htlc_base_key,
 409                         per_htlc: HashMap::new(),
 410                 };
 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_tx_cache,
 420                         remote_csv,
 421                         key_storage,
 422                         pending_claim_requests: HashMap::new(),
 423                         claimable_outpoints: HashMap::new(),
 424                         onchain_events_waiting_threshold_conf: HashMap::new(),
 425
 426                         secp_ctx: Secp256k1::new(),
 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, L: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F, logger: L) -> Option<(Option<u32>, u64, Transaction)>
 477                 where F::Target: FeeEstimator,
 478                                         L::Target: Logger,
 479         {
 480                 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
 481                 let mut inputs = Vec::new();
 482                 for outp in cached_claim_datas.per_input_material.keys() {
 483                         log_trace!(logger, "Outpoint {}:{}", outp.txid, outp.vout);
 484                         inputs.push(TxIn {
 485                                 previous_output: *outp,
 486                                 script_sig: Script::new(),
 487                                 sequence: 0xfffffffd,
 488                                 witness: Vec::new(),
 489                         });
 490                 }
 491                 let mut bumped_tx = Transaction {
 492                         version: 2,
 493                         lock_time: 0,
 494                         input: inputs,
 495                         output: vec![TxOut {
 496                                 script_pubkey: self.destination_script.clone(),
 497                                 value: 0
 498                         }],
 499                 };
 500
 501                 macro_rules! RBF_bump {
 502                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 503                                 {
 504                                         let mut used_feerate;
 505                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 506                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 507                                                 let mut value = $amount;
 508                                                 if subtract_high_prio_fee!(logger, $fee_estimator, value, $predicted_weight, used_feerate) {
 509                                                         // Overflow check is done in subtract_high_prio_fee
 510                                                         $amount - value
 511                                                 } else {
 512                                                         log_trace!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 513                                                         return None;
 514                                                 }
 515                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 516                                         } else {
 517                                                 let fee = $old_feerate * $predicted_weight / 750;
 518                                                 if $amount <= fee {
 519                                                         log_trace!(logger, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 520                                                         return None;
 521                                                 }
 522                                                 fee
 523                                         };
 524
 525                                         let previous_fee = $old_feerate * $predicted_weight / 1000;
 526                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
 527                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 528                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 529                                         //      * 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.
 530                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 531                                                 new_fee + previous_fee + min_relay_fee - new_fee
 532                                         } else {
 533                                                 new_fee
 534                                         };
 535                                         Some((new_fee, new_fee * 1000 / $predicted_weight))
 536                                 }
 537                         }
 538                 }
 539
 540                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 541                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 542                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 543                 let mut inputs_witnesses_weight = 0;
 544                 let mut amt = 0;
 545                 let mut dynamic_fee = true;
 546                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 547                         match per_outp_material {
 548                                 &InputMaterial::Revoked { ref witness_script, ref is_htlc, ref amount, .. } => {
 549                                         inputs_witnesses_weight += Self::get_witnesses_weight(if !is_htlc { &[InputDescriptors::RevokedOutput] } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::OfferedHTLC) { &[InputDescriptors::RevokedOfferedHTLC] } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::AcceptedHTLC) { &[InputDescriptors::RevokedReceivedHTLC] } else { unreachable!() });
 550                                         amt += *amount;
 551                                 },
 552                                 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
 553                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 554                                         amt += *amount;
 555                                 },
 556                                 &InputMaterial::LocalHTLC { .. } => {
 557                                         dynamic_fee = false;
 558                                 },
 559                                 &InputMaterial::Funding { .. } => {
 560                                         dynamic_fee = false;
 561                                 }
 562                         }
 563                 }
 564                 if dynamic_fee {
 565                         let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
 566                         let mut new_feerate;
 567                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 568                         if cached_claim_datas.feerate_previous != 0 {
 569                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
 570                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 571                                         if new_fee > amt {
 572                                                 bumped_tx.output[0].value = 0;
 573                                         } else {
 574                                                 bumped_tx.output[0].value = amt - new_fee;
 575                                         }
 576                                         new_feerate = feerate;
 577                                 } else { return None; }
 578                         } else {
 579                                 if subtract_high_prio_fee!(logger, fee_estimator, amt, predicted_weight, new_feerate) {
 580                                         bumped_tx.output[0].value = amt;
 581                                 } else { return None; }
 582                         }
 583                         assert!(new_feerate != 0);
 584
 585                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 586                                 match per_outp_material {
 587                                         &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref is_htlc, ref amount } => {
 588                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 589                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 590                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 591                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 592                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 593                                                 if *is_htlc {
 594                                                         bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
 595                                                 } else {
 596                                                         bumped_tx.input[i].witness.push(vec!(1));
 597                                                 }
 598                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 599                                                 log_trace!(logger, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if !is_htlc { "to_local" } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::OfferedHTLC) { "offered" } else if HTLCType::scriptlen_to_htlctype(witness_script.len()) == Some(HTLCType::AcceptedHTLC) { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
 600                                         },
 601                                         &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
 602                                                 if !preimage.is_some() { bumped_tx.lock_time = *locktime }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation
 603                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 604                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 605                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 606                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 607                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 608                                                 if let &Some(preimage) = preimage {
 609                                                         bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
 610                                                 } else {
 611                                                         bumped_tx.input[i].witness.push(vec![]);
 612                                                 }
 613                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 614                                                 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);
 615                                         },
 616                                         _ => unreachable!()
 617                                 }
 618                         }
 619                         log_trace!(logger, "...with timer {}", new_timer.unwrap());
 620                         assert!(predicted_weight >= bumped_tx.get_weight());
 621                         return Some((new_timer, new_feerate, bumped_tx))
 622                 } else {
 623                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 624                                 match per_outp_material {
 625                                         &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
 626                                                 let htlc_tx = self.get_fully_signed_htlc_tx(outp, preimage);
 627                                                 if let Some(htlc_tx) = htlc_tx {
 628                                                         let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
 629                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 630                                                         log_trace!(logger, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
 631                                                         return Some((None, feerate, htlc_tx));
 632                                                 }
 633                                                 return None;
 634                                         },
 635                                         &InputMaterial::Funding { ref funding_redeemscript } => {
 636                                                 let signed_tx = self.get_fully_signed_local_tx(funding_redeemscript).unwrap();
 637                                                 // Timer set to $NEVER given we can't bump tx without anchor outputs
 638                                                 log_trace!(logger, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 639                                                 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
 640                                         }
 641                                         _ => unreachable!()
 642                                 }
 643                         }
 644                 }
 645                 None
 646         }
 647
 648         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)
 649                 where B::Target: BroadcasterInterface,
 650                       F::Target: FeeEstimator,
 651                                         L::Target: Logger,
 652         {
 653                 log_trace!(logger, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 654                 let mut new_claims = Vec::new();
 655                 let mut aggregated_claim = HashMap::new();
 656                 let mut aggregated_soonest = ::std::u32::MAX;
 657
 658                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 659                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 660                 for req in claimable_outpoints {
 661                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 662                         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 {
 663                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 664                                 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
 665                                         let mut single_input = HashMap::new();
 666                                         single_input.insert(req.outpoint, req.witness_data);
 667                                         new_claims.push((req.absolute_timelock, single_input));
 668                                 } else {
 669                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 670                                         if req.absolute_timelock < aggregated_soonest {
 671                                                 aggregated_soonest = req.absolute_timelock;
 672                                         }
 673                                 }
 674                         }
 675                 }
 676                 new_claims.push((aggregated_soonest, aggregated_claim));
 677
 678                 // Generate claim transactions and track them to bump if necessary at
 679                 // height timer expiration (i.e in how many blocks we're going to take action).
 680                 for (soonest_timelock, claim) in new_claims.drain(..) {
 681                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
 682                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 683                                 claim_material.height_timer = new_timer;
 684                                 claim_material.feerate_previous = new_feerate;
 685                                 let txid = tx.txid();
 686                                 for k in claim_material.per_input_material.keys() {
 687                                         log_trace!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 688                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 689                                 }
 690                                 self.pending_claim_requests.insert(txid, claim_material);
 691                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(tx));
 692                                 broadcaster.broadcast_transaction(&tx);
 693                         }
 694                 }
 695
 696                 let mut bump_candidates = HashMap::new();
 697                 for tx in txn_matched {
 698                         // Scan all input to verify is one of the outpoint spent is of interest for us
 699                         let mut claimed_outputs_material = Vec::new();
 700                         for inp in &tx.input {
 701                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 702                                         // If outpoint has claim request pending on it...
 703                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 704                                                 //... we need to verify equality between transaction outpoints and claim request
 705                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 706                                                 // by us.
 707                                                 let mut set_equality = true;
 708                                                 if claim_material.per_input_material.len() != tx.input.len() {
 709                                                         set_equality = false;
 710                                                 } else {
 711                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 712                                                                 if *claim_inp != tx_inp.previous_output {
 713                                                                         set_equality = false;
 714                                                                 }
 715                                                         }
 716                                                 }
 717
 718                                                 macro_rules! clean_claim_request_after_safety_delay {
 719                                                         () => {
 720                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 721                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 722                                                                         hash_map::Entry::Occupied(mut entry) => {
 723                                                                                 if !entry.get().contains(&new_event) {
 724                                                                                         entry.get_mut().push(new_event);
 725                                                                                 }
 726                                                                         },
 727                                                                         hash_map::Entry::Vacant(entry) => {
 728                                                                                 entry.insert(vec![new_event]);
 729                                                                         }
 730                                                                 }
 731                                                         }
 732                                                 }
 733
 734                                                 // If this is our transaction (or our counterparty spent all the outputs
 735                                                 // before we could anyway with same inputs order than us), wait for
 736                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 737                                                 if set_equality {
 738                                                         clean_claim_request_after_safety_delay!();
 739                                                 } else { // If false, generate new claim request with update outpoint set
 740                                                         let mut at_least_one_drop = false;
 741                                                         for input in tx.input.iter() {
 742                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 743                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 744                                                                         at_least_one_drop = true;
 745                                                                 }
 746                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 747                                                                 if claim_material.per_input_material.is_empty() {
 748                                                                         clean_claim_request_after_safety_delay!();
 749                                                                 }
 750                                                         }
 751                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 752                                                         if at_least_one_drop {
 753                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
 754                                                         }
 755                                                 }
 756                                                 break; //No need to iterate further, either tx is our or their
 757                                         } else {
 758                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 759                                         }
 760                                 }
 761                         }
 762                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 763                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 764                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 765                                         hash_map::Entry::Occupied(mut entry) => {
 766                                                 if !entry.get().contains(&new_event) {
 767                                                         entry.get_mut().push(new_event);
 768                                                 }
 769                                         },
 770                                         hash_map::Entry::Vacant(entry) => {
 771                                                 entry.insert(vec![new_event]);
 772                                         }
 773                                 }
 774                         }
 775                 }
 776
 777                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 778                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 779                         for ev in events {
 780                                 match ev {
 781                                         OnchainEvent::Claim { claim_request } => {
 782                                                 // We may remove a whole set of claim outpoints here, as these one may have
 783                                                 // been aggregated in a single tx and claimed so atomically
 784                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 785                                                         for outpoint in bump_material.per_input_material.keys() {
 786                                                                 self.claimable_outpoints.remove(&outpoint);
 787                                                         }
 788                                                 }
 789                                         },
 790                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 791                                                 self.claimable_outpoints.remove(&outpoint);
 792                                         }
 793                                 }
 794                         }
 795                 }
 796
 797                 // Check if any pending claim request must be rescheduled
 798                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 799                         if let Some(h) = claim_data.height_timer {
 800                                 if h == height {
 801                                         bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
 802                                 }
 803                         }
 804                 }
 805
 806                 // Build, bump and rebroadcast tx accordingly
 807                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 808                 for (first_claim_txid, claim_material) in bump_candidates.iter() {
 809                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 810                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(bump_tx));
 811                                 broadcaster.broadcast_transaction(&bump_tx);
 812                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 813                                         claim_material.height_timer = new_timer;
 814                                         claim_material.feerate_previous = new_feerate;
 815                                 }
 816                         }
 817                 }
 818         }
 819
 820         pub(super) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F, logger: L)
 821                 where B::Target: BroadcasterInterface,
 822                       F::Target: FeeEstimator,
 823                                         L::Target: Logger,
 824         {
 825                 let mut bump_candidates = HashMap::new();
 826                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 827                         //- our claim tx on a commitment tx output
 828                         //- resurect outpoint back in its claimable set and regenerate tx
 829                         for ev in events {
 830                                 match ev {
 831                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 832                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 833                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 834                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 835                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 836                                                                 // resurrected only one bump claim tx is going to be broadcast
 837                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 838                                                         }
 839                                                 }
 840                                         },
 841                                         _ => {},
 842                                 }
 843                         }
 844                 }
 845                 for (_, claim_material) in bump_candidates.iter_mut() {
 846                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 847                                 claim_material.height_timer = new_timer;
 848                                 claim_material.feerate_previous = new_feerate;
 849                                 broadcaster.broadcast_transaction(&bump_tx);
 850                         }
 851                 }
 852                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 853                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 854                 }
 855                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 856                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 857                 let mut remove_request = Vec::new();
 858                 self.claimable_outpoints.retain(|_, ref v|
 859                         if v.1 == height {
 860                         remove_request.push(v.0.clone());
 861                         false
 862                         } else { true });
 863                 for req in remove_request {
 864                         self.pending_claim_requests.remove(&req);
 865                 }
 866         }
 867
 868         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
 869                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 870                 // commitment transaction has been signed due to an event (either block height for
 871                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 872                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 873                 // for the aformentionned signed transaction.
 874                 if self.local_htlc_sigs.is_some() || self.prev_local_htlc_sigs.is_some() {
 875                         return Err(());
 876                 }
 877                 self.prev_local_commitment = self.local_commitment.take();
 878                 self.local_commitment = Some(tx);
 879                 Ok(())
 880         }
 881
 882         fn sign_latest_local_htlcs(&mut self) {
 883                 if let Some(ref local_commitment) = self.local_commitment {
 884                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 885                                 self.local_htlc_sigs = Some(Vec::new());
 886                                 let ret = self.local_htlc_sigs.as_mut().unwrap();
 887                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 888                                         if let Some(tx_idx) = htlc.transaction_output_index {
 889                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 890                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 891                                         } else {
 892                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 893                                         }
 894                                 }
 895                         }
 896                 }
 897         }
 898         fn sign_prev_local_htlcs(&mut self) {
 899                 if let Some(ref local_commitment) = self.prev_local_commitment {
 900                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 901                                 self.prev_local_htlc_sigs = Some(Vec::new());
 902                                 let ret = self.prev_local_htlc_sigs.as_mut().unwrap();
 903                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 904                                         if let Some(tx_idx) = htlc.transaction_output_index {
 905                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 906                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 907                                         } else {
 908                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 909                                         }
 910                                 }
 911                         }
 912                 }
 913         }
 914
 915         //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
 916         // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 917         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 918         // to monitor before.
 919         pub(super) fn get_fully_signed_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 920                 if let Some(ref mut local_commitment) = self.local_commitment {
 921                         match self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx) {
 922                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 923                                 Err(_) => return None,
 924                         }
 925                 } else {
 926                         None
 927                 }
 928         }
 929
 930         pub(super) fn provide_latest_remote_tx(&mut self, commitment_txid: Sha256dHash, htlcs: Vec<HTLCOutputInCommitment>) {
 931                 self.remote_tx_cache.per_htlc.insert(commitment_txid, htlcs);
 932         }
 933
 934         #[cfg(test)]
 935         pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 936                 if let Some(ref mut local_commitment) = self.local_commitment {
 937                         let local_commitment = local_commitment.clone();
 938                         match self.key_storage.sign_local_commitment(&local_commitment, &self.secp_ctx) {
 939                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 940                                 Err(_) => return None,
 941                         }
 942                 } else {
 943                         None
 944                 }
 945         }
 946
 947         pub(super) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 948                 let mut htlc_tx = None;
 949                 if self.local_commitment.is_some() {
 950                         let commitment_txid = self.local_commitment.as_ref().unwrap().txid();
 951                         if commitment_txid == outp.txid {
 952                                 self.sign_latest_local_htlcs();
 953                                 if let &Some(ref htlc_sigs) = &self.local_htlc_sigs {
 954                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 955                                         htlc_tx = Some(self.local_commitment.as_ref().unwrap()
 956                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
 957                                 }
 958                         }
 959                 }
 960                 if self.prev_local_commitment.is_some() {
 961                         let commitment_txid = self.prev_local_commitment.as_ref().unwrap().txid();
 962                         if commitment_txid == outp.txid {
 963                                 self.sign_prev_local_htlcs();
 964                                 if let &Some(ref htlc_sigs) = &self.prev_local_htlc_sigs {
 965                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
 966                                         htlc_tx = Some(self.prev_local_commitment.as_ref().unwrap()
 967                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
 968                                 }
 969                         }
 970                 }
 971                 htlc_tx
 972         }
 973
 974         #[cfg(test)]
 975         pub(super) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 976                 let latest_had_sigs = self.local_htlc_sigs.is_some();
 977                 let prev_had_sigs = self.prev_local_htlc_sigs.is_some();
 978                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
 979                 if !latest_had_sigs {
 980                         self.local_htlc_sigs = None;
 981                 }
 982                 if !prev_had_sigs {
 983                         self.prev_local_htlc_sigs = None;
 984                 }
 985                 ret
 986         }
 987 }