_ 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::{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<Txid, 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, Clone, Copy)]
 105 pub(crate) enum InputDescriptors {
 106         RevokedOfferedHTLC,
 107         RevokedReceivedHTLC,
 108         OfferedHTLC,
 109         ReceivedHTLC,
 110         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 111 }
 112
 113 impl Writeable for InputDescriptors {
 114         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 115                 match self {
 116                         &InputDescriptors::RevokedOfferedHTLC => {
 117                                 writer.write_all(&[0; 1])?;
 118                         },
 119                         &InputDescriptors::RevokedReceivedHTLC => {
 120                                 writer.write_all(&[1; 1])?;
 121                         },
 122                         &InputDescriptors::OfferedHTLC => {
 123                                 writer.write_all(&[2; 1])?;
 124                         },
 125                         &InputDescriptors::ReceivedHTLC => {
 126                                 writer.write_all(&[3; 1])?;
 127                         }
 128                         &InputDescriptors::RevokedOutput => {
 129                                 writer.write_all(&[4; 1])?;
 130                         }
 131                 }
 132                 Ok(())
 133         }
 134 }
 135
 136 impl Readable for InputDescriptors {
 137         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 138                 let input_descriptor = match <u8 as Readable>::read(reader)? {
 139                         0 => {
 140                                 InputDescriptors::RevokedOfferedHTLC
 141                         },
 142                         1 => {
 143                                 InputDescriptors::RevokedReceivedHTLC
 144                         },
 145                         2 => {
 146                                 InputDescriptors::OfferedHTLC
 147                         },
 148                         3 => {
 149                                 InputDescriptors::ReceivedHTLC
 150                         },
 151                         4 => {
 152                                 InputDescriptors::RevokedOutput
 153                         }
 154                         _ => return Err(DecodeError::InvalidValue),
 155                 };
 156                 Ok(input_descriptor)
 157         }
 158 }
 159
 160 macro_rules! subtract_high_prio_fee {
 161         ($logger: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 162                 {
 163                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
 164                         let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
 165                         if $value <= fee {
 166                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 167                                 fee = $used_feerate * ($predicted_weight as u64) / 1000;
 168                                 if $value <= fee {
 169                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 170                                         fee = $used_feerate * ($predicted_weight as u64) / 1000;
 171                                         if $value <= fee {
 172                                                 log_error!($logger, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 173                                                         fee, $value);
 174                                                 false
 175                                         } else {
 176                                                 log_warn!($logger, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 177                                                         $value);
 178                                                 $value -= fee;
 179                                                 true
 180                                         }
 181                                 } else {
 182                                         log_warn!($logger, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 183                                                 $value);
 184                                         $value -= fee;
 185                                         true
 186                                 }
 187                         } else {
 188                                 $value -= fee;
 189                                 true
 190                         }
 191                 }
 192         }
 193 }
 194
 195 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 196         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 197                 match Readable::read(reader)? {
 198                         0u8 => Ok(None),
 199                         1u8 => {
 200                                 let vlen: u64 = Readable::read(reader)?;
 201                                 let mut ret = Vec::with_capacity(cmp::min(vlen as usize, MAX_ALLOC_SIZE / ::std::mem::size_of::<Option<(usize, Signature)>>()));
 202                                 for _ in 0..vlen {
 203                                         ret.push(match Readable::read(reader)? {
 204                                                 0u8 => None,
 205                                                 1u8 => Some((<u64 as Readable>::read(reader)? as usize, Readable::read(reader)?)),
 206                                                 _ => return Err(DecodeError::InvalidValue)
 207                                         });
 208                                 }
 209                                 Ok(Some(ret))
 210                         },
 211                         _ => Err(DecodeError::InvalidValue),
 212                 }
 213         }
 214 }
 215
 216 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 217         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 218                 match self {
 219                         &Some(ref vec) => {
 220                                 1u8.write(writer)?;
 221                                 (vec.len() as u64).write(writer)?;
 222                                 for opt in vec.iter() {
 223                                         match opt {
 224                                                 &Some((ref idx, ref sig)) => {
 225                                                         1u8.write(writer)?;
 226                                                         (*idx as u64).write(writer)?;
 227                                                         sig.write(writer)?;
 228                                                 },
 229                                                 &None => 0u8.write(writer)?,
 230                                         }
 231                                 }
 232                         },
 233                         &None => 0u8.write(writer)?,
 234                 }
 235                 Ok(())
 236         }
 237 }
 238
 239
 240 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 241 /// do RBF bumping if possible.
 242 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 243         destination_script: Script,
 244         local_commitment: Option<LocalCommitmentTransaction>,
 245         // local_htlc_sigs and prev_local_htlc_sigs are in the order as they appear in the commitment
 246         // transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 247         // the set of HTLCs in the LocalCommitmentTransaction (including those which do not appear in
 248         // the commitment transaction).
 249         local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 250         prev_local_commitment: Option<LocalCommitmentTransaction>,
 251         prev_local_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 252         local_csv: u16,
 253         remote_tx_cache: RemoteTxCache,
 254         remote_csv: u16,
 255
 256         key_storage: ChanSigner,
 257
 258         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 259         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 260         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 261         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 262         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 263         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 264         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 265         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 266         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 267         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 268         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 269         #[cfg(test)] // Used in functional_test to verify sanitization
 270         pub pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 271         #[cfg(not(test))]
 272         pending_claim_requests: HashMap<Txid, ClaimTxBumpMaterial>,
 273
 274         // Used to link outpoints claimed in a connected block to a pending claim request.
 275         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 276         // Value is (pending claim request identifier, confirmation_block), identifier
 277         // is txid of the initial claiming transaction and is immutable until outpoint is
 278         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 279         // block with output gets disconnected.
 280         #[cfg(test)] // Used in functional_test to verify sanitization
 281         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 282         #[cfg(not(test))]
 283         claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 284
 285         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 286
 287         secp_ctx: Secp256k1<secp256k1::All>,
 288 }
 289
 290 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 291         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 292                 self.destination_script.write(writer)?;
 293                 self.local_commitment.write(writer)?;
 294                 self.local_htlc_sigs.write(writer)?;
 295                 self.prev_local_commitment.write(writer)?;
 296                 self.prev_local_htlc_sigs.write(writer)?;
 297
 298                 self.local_csv.write(writer)?;
 299
 300                 self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
 301                 self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
 302                 writer.write_all(&byte_utils::be64_to_array(self.remote_tx_cache.per_htlc.len() as u64))?;
 303                 for (ref txid, ref htlcs) in self.remote_tx_cache.per_htlc.iter() {
 304                         writer.write_all(&txid[..])?;
 305                         writer.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
 306                         for &ref htlc in htlcs.iter() {
 307                                 htlc.write(writer)?;
 308                         }
 309                 }
 310                 self.remote_csv.write(writer)?;
 311
 312                 self.key_storage.write(writer)?;
 313
 314                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 315                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 316                         ancestor_claim_txid.write(writer)?;
 317                         claim_tx_data.write(writer)?;
 318                 }
 319
 320                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 321                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 322                         outp.write(writer)?;
 323                         claim_and_height.0.write(writer)?;
 324                         claim_and_height.1.write(writer)?;
 325                 }
 326
 327                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 328                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 329                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 330                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 331                         for ev in events.iter() {
 332                                 match *ev {
 333                                         OnchainEvent::Claim { ref claim_request } => {
 334                                                 writer.write_all(&[0; 1])?;
 335                                                 claim_request.write(writer)?;
 336                                         },
 337                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 338                                                 writer.write_all(&[1; 1])?;
 339                                                 outpoint.write(writer)?;
 340                                                 input_material.write(writer)?;
 341                                         }
 342                                 }
 343                         }
 344                 }
 345                 Ok(())
 346         }
 347 }
 348
 349 impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
 350         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 351                 let destination_script = Readable::read(reader)?;
 352
 353                 let local_commitment = Readable::read(reader)?;
 354                 let local_htlc_sigs = Readable::read(reader)?;
 355                 let prev_local_commitment = Readable::read(reader)?;
 356                 let prev_local_htlc_sigs = Readable::read(reader)?;
 357
 358                 let local_csv = Readable::read(reader)?;
 359
 360                 let remote_tx_cache = {
 361                         let remote_delayed_payment_base_key = Readable::read(reader)?;
 362                         let remote_htlc_base_key = Readable::read(reader)?;
 363                         let per_htlc_len: u64 = Readable::read(reader)?;
 364                         let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
 365                         for _  in 0..per_htlc_len {
 366                                 let txid: Txid = Readable::read(reader)?;
 367                                 let htlcs_count: u64 = Readable::read(reader)?;
 368                                 let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
 369                                 for _ in 0..htlcs_count {
 370                                         let htlc = Readable::read(reader)?;
 371                                         htlcs.push(htlc);
 372                                 }
 373                                 if let Some(_) = per_htlc.insert(txid, htlcs) {
 374                                         return Err(DecodeError::InvalidValue);
 375                                 }
 376                         }
 377                         RemoteTxCache {
 378                                 remote_delayed_payment_base_key,
 379                                 remote_htlc_base_key,
 380                                 per_htlc,
 381                         }
 382                 };
 383                 let remote_csv = Readable::read(reader)?;
 384
 385                 let key_storage = Readable::read(reader)?;
 386
 387                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 388                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 389                 for _ in 0..pending_claim_requests_len {
 390                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 391                 }
 392
 393                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 394                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 395                 for _ in 0..claimable_outpoints_len {
 396                         let outpoint = Readable::read(reader)?;
 397                         let ancestor_claim_txid = Readable::read(reader)?;
 398                         let height = Readable::read(reader)?;
 399                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 400                 }
 401                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 402                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 403                 for _ in 0..waiting_threshold_conf_len {
 404                         let height_target = Readable::read(reader)?;
 405                         let events_len: u64 = Readable::read(reader)?;
 406                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 407                         for _ in 0..events_len {
 408                                 let ev = match <u8 as Readable>::read(reader)? {
 409                                         0 => {
 410                                                 let claim_request = Readable::read(reader)?;
 411                                                 OnchainEvent::Claim {
 412                                                         claim_request
 413                                                 }
 414                                         },
 415                                         1 => {
 416                                                 let outpoint = Readable::read(reader)?;
 417                                                 let input_material = Readable::read(reader)?;
 418                                                 OnchainEvent::ContentiousOutpoint {
 419                                                         outpoint,
 420                                                         input_material
 421                                                 }
 422                                         }
 423                                         _ => return Err(DecodeError::InvalidValue),
 424                                 };
 425                                 events.push(ev);
 426                         }
 427                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 428                 }
 429
 430                 Ok(OnchainTxHandler {
 431                         destination_script,
 432                         local_commitment,
 433                         local_htlc_sigs,
 434                         prev_local_commitment,
 435                         prev_local_htlc_sigs,
 436                         local_csv,
 437                         remote_tx_cache,
 438                         remote_csv,
 439                         key_storage,
 440                         claimable_outpoints,
 441                         pending_claim_requests,
 442                         onchain_events_waiting_threshold_conf,
 443                         secp_ctx: Secp256k1::new(),
 444                 })
 445         }
 446 }
 447
 448 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 449         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 {
 450
 451                 let key_storage = keys;
 452
 453                 let remote_tx_cache = RemoteTxCache {
 454                         remote_delayed_payment_base_key,
 455                         remote_htlc_base_key,
 456                         per_htlc: HashMap::new(),
 457                 };
 458
 459                 OnchainTxHandler {
 460                         destination_script,
 461                         local_commitment: None,
 462                         local_htlc_sigs: None,
 463                         prev_local_commitment: None,
 464                         prev_local_htlc_sigs: None,
 465                         local_csv,
 466                         remote_tx_cache,
 467                         remote_csv,
 468                         key_storage,
 469                         pending_claim_requests: HashMap::new(),
 470                         claimable_outpoints: HashMap::new(),
 471                         onchain_events_waiting_threshold_conf: HashMap::new(),
 472
 473                         secp_ctx: Secp256k1::new(),
 474                 }
 475         }
 476
 477         pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
 478                 let mut tx_weight = 2; // count segwit flags
 479                 for inp in inputs {
 480                         // We use expected weight (and not actual) as signatures and time lock delays may vary
 481                         tx_weight +=  match inp {
 482                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 483                                 &InputDescriptors::RevokedOfferedHTLC => {
 484                                         1 + 1 + 73 + 1 + 33 + 1 + 133
 485                                 },
 486                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 487                                 &InputDescriptors::RevokedReceivedHTLC => {
 488                                         1 + 1 + 73 + 1 + 33 + 1 + 139
 489                                 },
 490                                 // number_of_witness_elements + sig_length + remotehtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
 491                                 &InputDescriptors::OfferedHTLC => {
 492                                         1 + 1 + 73 + 1 + 32 + 1 + 133
 493                                 },
 494                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 495                                 &InputDescriptors::ReceivedHTLC => {
 496                                         1 + 1 + 73 + 1 + 1 + 1 + 139
 497                                 },
 498                                 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
 499                                 &InputDescriptors::RevokedOutput => {
 500                                         1 + 1 + 73 + 1 + 1 + 1 + 77
 501                                 },
 502                         };
 503                 }
 504                 tx_weight
 505         }
 506
 507         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 508         /// 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
 509         /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
 510         /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
 511         /// frequency of the bump and so increase our bets of success.
 512         fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
 513                 if timelock_expiration <= current_height + 3 {
 514                         return current_height + 1
 515                 } else if timelock_expiration - current_height <= 15 {
 516                         return current_height + 3
 517                 }
 518                 current_height + 15
 519         }
 520
 521         /// 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
 522         /// (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.
 523         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)>
 524                 where F::Target: FeeEstimator,
 525                                         L::Target: Logger,
 526         {
 527                 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
 528                 let mut inputs = Vec::new();
 529                 for outp in cached_claim_datas.per_input_material.keys() {
 530                         log_trace!(logger, "Outpoint {}:{}", outp.txid, outp.vout);
 531                         inputs.push(TxIn {
 532                                 previous_output: *outp,
 533                                 script_sig: Script::new(),
 534                                 sequence: 0xfffffffd,
 535                                 witness: Vec::new(),
 536                         });
 537                 }
 538                 let mut bumped_tx = Transaction {
 539                         version: 2,
 540                         lock_time: 0,
 541                         input: inputs,
 542                         output: vec![TxOut {
 543                                 script_pubkey: self.destination_script.clone(),
 544                                 value: 0
 545                         }],
 546                 };
 547
 548                 macro_rules! RBF_bump {
 549                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 550                                 {
 551                                         let mut used_feerate;
 552                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 553                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 554                                                 let mut value = $amount;
 555                                                 if subtract_high_prio_fee!(logger, $fee_estimator, value, $predicted_weight, used_feerate) {
 556                                                         // Overflow check is done in subtract_high_prio_fee
 557                                                         $amount - value
 558                                                 } else {
 559                                                         log_trace!(logger, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 560                                                         return None;
 561                                                 }
 562                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 563                                         } else {
 564                                                 let fee = $old_feerate * $predicted_weight / 750;
 565                                                 if $amount <= fee {
 566                                                         log_trace!(logger, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 567                                                         return None;
 568                                                 }
 569                                                 fee
 570                                         };
 571
 572                                         let previous_fee = $old_feerate * $predicted_weight / 1000;
 573                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
 574                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 575                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 576                                         //      * 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.
 577                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 578                                                 new_fee + previous_fee + min_relay_fee - new_fee
 579                                         } else {
 580                                                 new_fee
 581                                         };
 582                                         Some((new_fee, new_fee * 1000 / $predicted_weight))
 583                                 }
 584                         }
 585                 }
 586
 587                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 588                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 589                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 590                 let mut inputs_witnesses_weight = 0;
 591                 let mut amt = 0;
 592                 let mut dynamic_fee = true;
 593                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 594                         match per_outp_material {
 595                                 &InputMaterial::Revoked { ref input_descriptor, ref amount, .. } => {
 596                                         inputs_witnesses_weight += Self::get_witnesses_weight(&[*input_descriptor]);
 597                                         amt += *amount;
 598                                 },
 599                                 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
 600                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 601                                         amt += *amount;
 602                                 },
 603                                 &InputMaterial::LocalHTLC { .. } => {
 604                                         dynamic_fee = false;
 605                                 },
 606                                 &InputMaterial::Funding { .. } => {
 607                                         dynamic_fee = false;
 608                                 }
 609                         }
 610                 }
 611                 if dynamic_fee {
 612                         let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
 613                         let mut new_feerate;
 614                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 615                         if cached_claim_datas.feerate_previous != 0 {
 616                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
 617                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 618                                         if new_fee > amt {
 619                                                 bumped_tx.output[0].value = 0;
 620                                         } else {
 621                                                 bumped_tx.output[0].value = amt - new_fee;
 622                                         }
 623                                         new_feerate = feerate;
 624                                 } else { return None; }
 625                         } else {
 626                                 if subtract_high_prio_fee!(logger, fee_estimator, amt, predicted_weight, new_feerate) {
 627                                         bumped_tx.output[0].value = amt;
 628                                 } else { return None; }
 629                         }
 630                         assert!(new_feerate != 0);
 631
 632                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 633                                 match per_outp_material {
 634                                         &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref input_descriptor, ref amount } => {
 635                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 636                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 637                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 638                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 639                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 640                                                 if *input_descriptor !=  InputDescriptors::RevokedOutput {
 641                                                         bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
 642                                                 } else {
 643                                                         bumped_tx.input[i].witness.push(vec!(1));
 644                                                 }
 645                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 646                                                 log_trace!(logger, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_local" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
 647                                         },
 648                                         &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
 649                                                 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
 650                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 651                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 652                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 653                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 654                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 655                                                 if let &Some(preimage) = preimage {
 656                                                         bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
 657                                                 } else {
 658                                                         bumped_tx.input[i].witness.push(vec![]);
 659                                                 }
 660                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 661                                                 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);
 662                                         },
 663                                         _ => unreachable!()
 664                                 }
 665                         }
 666                         log_trace!(logger, "...with timer {}", new_timer.unwrap());
 667                         assert!(predicted_weight >= bumped_tx.get_weight());
 668                         return Some((new_timer, new_feerate, bumped_tx))
 669                 } else {
 670                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 671                                 match per_outp_material {
 672                                         &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
 673                                                 let htlc_tx = self.get_fully_signed_htlc_tx(outp, preimage);
 674                                                 if let Some(htlc_tx) = htlc_tx {
 675                                                         let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
 676                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 677                                                         log_trace!(logger, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
 678                                                         return Some((None, feerate, htlc_tx));
 679                                                 }
 680                                                 return None;
 681                                         },
 682                                         &InputMaterial::Funding { ref funding_redeemscript } => {
 683                                                 let signed_tx = self.get_fully_signed_local_tx(funding_redeemscript).unwrap();
 684                                                 // Timer set to $NEVER given we can't bump tx without anchor outputs
 685                                                 log_trace!(logger, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 686                                                 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
 687                                         }
 688                                         _ => unreachable!()
 689                                 }
 690                         }
 691                 }
 692                 None
 693         }
 694
 695         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)
 696                 where B::Target: BroadcasterInterface,
 697                       F::Target: FeeEstimator,
 698                                         L::Target: Logger,
 699         {
 700                 log_trace!(logger, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 701                 let mut new_claims = Vec::new();
 702                 let mut aggregated_claim = HashMap::new();
 703                 let mut aggregated_soonest = ::std::u32::MAX;
 704
 705                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 706                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 707                 for req in claimable_outpoints {
 708                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 709                         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 {
 710                                 log_trace!(logger, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 711                                 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
 712                                         let mut single_input = HashMap::new();
 713                                         single_input.insert(req.outpoint, req.witness_data);
 714                                         new_claims.push((req.absolute_timelock, single_input));
 715                                 } else {
 716                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 717                                         if req.absolute_timelock < aggregated_soonest {
 718                                                 aggregated_soonest = req.absolute_timelock;
 719                                         }
 720                                 }
 721                         }
 722                 }
 723                 new_claims.push((aggregated_soonest, aggregated_claim));
 724
 725                 // Generate claim transactions and track them to bump if necessary at
 726                 // height timer expiration (i.e in how many blocks we're going to take action).
 727                 for (soonest_timelock, claim) in new_claims.drain(..) {
 728                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
 729                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 730                                 claim_material.height_timer = new_timer;
 731                                 claim_material.feerate_previous = new_feerate;
 732                                 let txid = tx.txid();
 733                                 for k in claim_material.per_input_material.keys() {
 734                                         log_trace!(logger, "Registering claiming request for {}:{}", k.txid, k.vout);
 735                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 736                                 }
 737                                 self.pending_claim_requests.insert(txid, claim_material);
 738                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(tx));
 739                                 broadcaster.broadcast_transaction(&tx);
 740                         }
 741                 }
 742
 743                 let mut bump_candidates = HashMap::new();
 744                 for tx in txn_matched {
 745                         // Scan all input to verify is one of the outpoint spent is of interest for us
 746                         let mut claimed_outputs_material = Vec::new();
 747                         for inp in &tx.input {
 748                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 749                                         // If outpoint has claim request pending on it...
 750                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 751                                                 //... we need to verify equality between transaction outpoints and claim request
 752                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 753                                                 // by us.
 754                                                 let mut set_equality = true;
 755                                                 if claim_material.per_input_material.len() != tx.input.len() {
 756                                                         set_equality = false;
 757                                                 } else {
 758                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 759                                                                 if *claim_inp != tx_inp.previous_output {
 760                                                                         set_equality = false;
 761                                                                 }
 762                                                         }
 763                                                 }
 764
 765                                                 macro_rules! clean_claim_request_after_safety_delay {
 766                                                         () => {
 767                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 768                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 769                                                                         hash_map::Entry::Occupied(mut entry) => {
 770                                                                                 if !entry.get().contains(&new_event) {
 771                                                                                         entry.get_mut().push(new_event);
 772                                                                                 }
 773                                                                         },
 774                                                                         hash_map::Entry::Vacant(entry) => {
 775                                                                                 entry.insert(vec![new_event]);
 776                                                                         }
 777                                                                 }
 778                                                         }
 779                                                 }
 780
 781                                                 // If this is our transaction (or our counterparty spent all the outputs
 782                                                 // before we could anyway with same inputs order than us), wait for
 783                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 784                                                 if set_equality {
 785                                                         clean_claim_request_after_safety_delay!();
 786                                                 } else { // If false, generate new claim request with update outpoint set
 787                                                         let mut at_least_one_drop = false;
 788                                                         for input in tx.input.iter() {
 789                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 790                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 791                                                                         at_least_one_drop = true;
 792                                                                 }
 793                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 794                                                                 if claim_material.per_input_material.is_empty() {
 795                                                                         clean_claim_request_after_safety_delay!();
 796                                                                 }
 797                                                         }
 798                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 799                                                         if at_least_one_drop {
 800                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
 801                                                         }
 802                                                 }
 803                                                 break; //No need to iterate further, either tx is our or their
 804                                         } else {
 805                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 806                                         }
 807                                 }
 808                         }
 809                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 810                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 811                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 812                                         hash_map::Entry::Occupied(mut entry) => {
 813                                                 if !entry.get().contains(&new_event) {
 814                                                         entry.get_mut().push(new_event);
 815                                                 }
 816                                         },
 817                                         hash_map::Entry::Vacant(entry) => {
 818                                                 entry.insert(vec![new_event]);
 819                                         }
 820                                 }
 821                         }
 822                 }
 823
 824                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 825                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 826                         for ev in events {
 827                                 match ev {
 828                                         OnchainEvent::Claim { claim_request } => {
 829                                                 // We may remove a whole set of claim outpoints here, as these one may have
 830                                                 // been aggregated in a single tx and claimed so atomically
 831                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 832                                                         for outpoint in bump_material.per_input_material.keys() {
 833                                                                 self.claimable_outpoints.remove(&outpoint);
 834                                                         }
 835                                                 }
 836                                         },
 837                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 838                                                 self.claimable_outpoints.remove(&outpoint);
 839                                         }
 840                                 }
 841                         }
 842                 }
 843
 844                 // Check if any pending claim request must be rescheduled
 845                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 846                         if let Some(h) = claim_data.height_timer {
 847                                 if h == height {
 848                                         bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
 849                                 }
 850                         }
 851                 }
 852
 853                 // Build, bump and rebroadcast tx accordingly
 854                 log_trace!(logger, "Bumping {} candidates", bump_candidates.len());
 855                 for (first_claim_txid, claim_material) in bump_candidates.iter() {
 856                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 857                                 log_trace!(logger, "Broadcast onchain {}", log_tx!(bump_tx));
 858                                 broadcaster.broadcast_transaction(&bump_tx);
 859                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 860                                         claim_material.height_timer = new_timer;
 861                                         claim_material.feerate_previous = new_feerate;
 862                                 }
 863                         }
 864                 }
 865         }
 866
 867         pub(super) fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F, logger: L)
 868                 where B::Target: BroadcasterInterface,
 869                       F::Target: FeeEstimator,
 870                                         L::Target: Logger,
 871         {
 872                 let mut bump_candidates = HashMap::new();
 873                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 874                         //- our claim tx on a commitment tx output
 875                         //- resurect outpoint back in its claimable set and regenerate tx
 876                         for ev in events {
 877                                 match ev {
 878                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 879                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 880                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 881                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 882                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 883                                                                 // resurrected only one bump claim tx is going to be broadcast
 884                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 885                                                         }
 886                                                 }
 887                                         },
 888                                         _ => {},
 889                                 }
 890                         }
 891                 }
 892                 for (_, claim_material) in bump_candidates.iter_mut() {
 893                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator, &*logger) {
 894                                 claim_material.height_timer = new_timer;
 895                                 claim_material.feerate_previous = new_feerate;
 896                                 broadcaster.broadcast_transaction(&bump_tx);
 897                         }
 898                 }
 899                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 900                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 901                 }
 902                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 903                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 904                 let mut remove_request = Vec::new();
 905                 self.claimable_outpoints.retain(|_, ref v|
 906                         if v.1 == height {
 907                         remove_request.push(v.0.clone());
 908                         false
 909                         } else { true });
 910                 for req in remove_request {
 911                         self.pending_claim_requests.remove(&req);
 912                 }
 913         }
 914
 915         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
 916                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 917                 // commitment transaction has been signed due to an event (either block height for
 918                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 919                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 920                 // for the aformentionned signed transaction.
 921                 if self.local_htlc_sigs.is_some() || self.prev_local_htlc_sigs.is_some() {
 922                         return Err(());
 923                 }
 924                 self.prev_local_commitment = self.local_commitment.take();
 925                 self.local_commitment = Some(tx);
 926                 Ok(())
 927         }
 928
 929         fn sign_latest_local_htlcs(&mut self) {
 930                 if let Some(ref local_commitment) = self.local_commitment {
 931                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 932                                 self.local_htlc_sigs = Some(Vec::new());
 933                                 let ret = self.local_htlc_sigs.as_mut().unwrap();
 934                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 935                                         if let Some(tx_idx) = htlc.transaction_output_index {
 936                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 937                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 938                                         } else {
 939                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 940                                         }
 941                                 }
 942                         }
 943                 }
 944         }
 945         fn sign_prev_local_htlcs(&mut self) {
 946                 if let Some(ref local_commitment) = self.prev_local_commitment {
 947                         if let Ok(sigs) = self.key_storage.sign_local_commitment_htlc_transactions(local_commitment, self.local_csv, &self.secp_ctx) {
 948                                 self.prev_local_htlc_sigs = Some(Vec::new());
 949                                 let ret = self.prev_local_htlc_sigs.as_mut().unwrap();
 950                                 for (htlc_idx, (local_sig, &(ref htlc, _))) in sigs.iter().zip(local_commitment.per_htlc.iter()).enumerate() {
 951                                         if let Some(tx_idx) = htlc.transaction_output_index {
 952                                                 if ret.len() <= tx_idx as usize { ret.resize(tx_idx as usize + 1, None); }
 953                                                 ret[tx_idx as usize] = Some((htlc_idx, local_sig.expect("Did not receive a signature for a non-dust HTLC")));
 954                                         } else {
 955                                                 assert!(local_sig.is_none(), "Received a signature for a dust HTLC");
 956                                         }
 957                                 }
 958                         }
 959                 }
 960         }
 961
 962         //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
 963         // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 964         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 965         // to monitor before.
 966         pub(super) fn get_fully_signed_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 967                 if let Some(ref mut local_commitment) = self.local_commitment {
 968                         match self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx) {
 969                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 970                                 Err(_) => return None,
 971                         }
 972                 } else {
 973                         None
 974                 }
 975         }
 976
 977         pub(super) fn provide_latest_remote_tx(&mut self, commitment_txid: Txid, htlcs: Vec<HTLCOutputInCommitment>) {
 978                 self.remote_tx_cache.per_htlc.insert(commitment_txid, htlcs);
 979         }
 980
 981         #[cfg(test)]
 982         pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
 983                 if let Some(ref mut local_commitment) = self.local_commitment {
 984                         let local_commitment = local_commitment.clone();
 985                         match self.key_storage.sign_local_commitment(&local_commitment, &self.secp_ctx) {
 986                                 Ok(sig) => Some(local_commitment.add_local_sig(funding_redeemscript, sig)),
 987                                 Err(_) => return None,
 988                         }
 989                 } else {
 990                         None
 991                 }
 992         }
 993
 994         pub(super) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 995                 let mut htlc_tx = None;
 996                 if self.local_commitment.is_some() {
 997                         let commitment_txid = self.local_commitment.as_ref().unwrap().txid();
 998                         if commitment_txid == outp.txid {
 999                                 self.sign_latest_local_htlcs();
1000                                 if let &Some(ref htlc_sigs) = &self.local_htlc_sigs {
1001                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1002                                         htlc_tx = Some(self.local_commitment.as_ref().unwrap()
1003                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
1004                                 }
1005                         }
1006                 }
1007                 if self.prev_local_commitment.is_some() {
1008                         let commitment_txid = self.prev_local_commitment.as_ref().unwrap().txid();
1009                         if commitment_txid == outp.txid {
1010                                 self.sign_prev_local_htlcs();
1011                                 if let &Some(ref htlc_sigs) = &self.prev_local_htlc_sigs {
1012                                         let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
1013                                         htlc_tx = Some(self.prev_local_commitment.as_ref().unwrap()
1014                                                 .get_signed_htlc_tx(*htlc_idx, htlc_sig, preimage, self.local_csv));
1015                                 }
1016                         }
1017                 }
1018                 htlc_tx
1019         }
1020
1021         #[cfg(test)]
1022         pub(super) fn unsafe_get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
1023                 let latest_had_sigs = self.local_htlc_sigs.is_some();
1024                 let prev_had_sigs = self.prev_local_htlc_sigs.is_some();
1025                 let ret = self.get_fully_signed_htlc_tx(outp, preimage);
1026                 if !latest_had_sigs {
1027                         self.local_htlc_sigs = None;
1028                 }
1029                 if !prev_had_sigs {
1030                         self.prev_local_htlc_sigs = None;
1031                 }
1032                 ret
1033         }
1034 }