_ 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_hashes::sha256d::Hash as Sha256dHash;
  12
  13 use secp256k1::{Secp256k1, Signature};
  14 use secp256k1;
  15
  16 use ln::msgs::DecodeError;
  17 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
  18 use ln::channelmanager::HTLCSource;
  19 use ln::chan_utils;
  20 use ln::chan_utils::{HTLCType, LocalCommitmentTransaction, TxCreationKeys, 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::{ReadableArgs, Readable, Writer, Writeable};
  25 use util::byte_utils;
  26
  27 use std::collections::{HashMap, hash_map, HashSet};
  28 use std::sync::Arc;
  29 use std::cmp;
  30 use std::ops::Deref;
  31
  32 const MAX_ALLOC_SIZE: usize = 64*1024;
  33
  34 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
  35 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
  36 #[derive(Clone, PartialEq)]
  37 enum OnchainEvent {
  38         /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
  39         /// bump-txn candidate buffer.
  40         Claim {
  41                 claim_request: Sha256dHash,
  42         },
  43         /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
  44         /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
  45         /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
  46         ContentiousOutpoint {
  47                 outpoint: BitcoinOutPoint,
  48                 input_material: InputMaterial,
  49         }
  50 }
  51
  52 /// Cache public keys and feerate used to compute any HTLC transaction.
  53 /// We only keep state for latest 2 commitment transactions as we should
  54 /// never have to generate HTLC txn for revoked local commitment
  55 struct HTLCTxCache {
  56         local_keys: TxCreationKeys,
  57         feerate_per_kw: u64,
  58         per_htlc: HashMap<u32, (HTLCOutputInCommitment, Option<Signature>)>
  59 }
  60
  61 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
  62 #[derive(Clone, PartialEq)]
  63 pub struct ClaimTxBumpMaterial {
  64         // At every block tick, used to check if pending claiming tx is taking too
  65         // much time for confirmation and we need to bump it.
  66         height_timer: Option<u32>,
  67         // Tracked in case of reorg to wipe out now-superflous bump material
  68         feerate_previous: u64,
  69         // Soonest timelocks among set of outpoints claimed, used to compute
  70         // a priority of not feerate
  71         soonest_timelock: u32,
  72         // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
  73         per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
  74 }
  75
  76 impl Writeable for ClaimTxBumpMaterial  {
  77         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
  78                 self.height_timer.write(writer)?;
  79                 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
  80                 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
  81                 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
  82                 for (outp, tx_material) in self.per_input_material.iter() {
  83                         outp.write(writer)?;
  84                         tx_material.write(writer)?;
  85                 }
  86                 Ok(())
  87         }
  88 }
  89
  90 impl Readable for ClaimTxBumpMaterial {
  91         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
  92                 let height_timer = Readable::read(reader)?;
  93                 let feerate_previous = Readable::read(reader)?;
  94                 let soonest_timelock = Readable::read(reader)?;
  95                 let per_input_material_len: u64 = Readable::read(reader)?;
  96                 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
  97                 for _ in 0 ..per_input_material_len {
  98                         let outpoint = Readable::read(reader)?;
  99                         let input_material = Readable::read(reader)?;
 100                         per_input_material.insert(outpoint, input_material);
 101                 }
 102                 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
 103         }
 104 }
 105
 106 #[derive(PartialEq)]
 107 pub(super) enum InputDescriptors {
 108         RevokedOfferedHTLC,
 109         RevokedReceivedHTLC,
 110         OfferedHTLC,
 111         ReceivedHTLC,
 112         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 113 }
 114
 115 macro_rules! subtract_high_prio_fee {
 116         ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 117                 {
 118                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
 119                         let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
 120                         if $value <= fee {
 121                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 122                                 fee = $used_feerate * ($predicted_weight as u64) / 1000;
 123                                 if $value <= fee {
 124                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 125                                         fee = $used_feerate * ($predicted_weight as u64) / 1000;
 126                                         if $value <= fee {
 127                                                 log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 128                                                         fee, $value);
 129                                                 false
 130                                         } else {
 131                                                 log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 132                                                         $value);
 133                                                 $value -= fee;
 134                                                 true
 135                                         }
 136                                 } else {
 137                                         log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 138                                                 $value);
 139                                         $value -= fee;
 140                                         true
 141                                 }
 142                         } else {
 143                                 $value -= fee;
 144                                 true
 145                         }
 146                 }
 147         }
 148 }
 149
 150
 151 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 152 /// do RBF bumping if possible.
 153 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 154         destination_script: Script,
 155         funding_redeemscript: Script,
 156         local_commitment: Option<LocalCommitmentTransaction>,
 157         prev_local_commitment: Option<LocalCommitmentTransaction>,
 158         current_htlc_cache: Option<HTLCTxCache>,
 159         prev_htlc_cache: Option<HTLCTxCache>,
 160
 161         key_storage: ChanSigner,
 162
 163         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 164         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 165         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 166         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 167         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 168         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 169         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 170         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 171         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 172         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 173         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 174         #[cfg(test)] // Used in functional_test to verify sanitization
 175         pub pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
 176         #[cfg(not(test))]
 177         pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
 178
 179         // Used to link outpoints claimed in a connected block to a pending claim request.
 180         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 181         // Value is (pending claim request identifier, confirmation_block), identifier
 182         // is txid of the initial claiming transaction and is immutable until outpoint is
 183         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 184         // block with output gets disconnected.
 185         #[cfg(test)] // Used in functional_test to verify sanitization
 186         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
 187         #[cfg(not(test))]
 188         claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
 189
 190         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 191
 192         secp_ctx: Secp256k1<secp256k1::All>,
 193         logger: Arc<Logger>
 194 }
 195
 196 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 197         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 198                 self.destination_script.write(writer)?;
 199                 self.funding_redeemscript.write(writer)?;
 200                 self.local_commitment.write(writer)?;
 201                 self.prev_local_commitment.write(writer)?;
 202
 203                 macro_rules! serialize_htlc_cache {
 204                         ($cache: expr) => {
 205                                 $cache.local_keys.write(writer)?;
 206                                 $cache.feerate_per_kw.write(writer)?;
 207                                 writer.write_all(&byte_utils::be64_to_array($cache.per_htlc.len() as u64))?;
 208                                 for (_, &(ref htlc, ref sig)) in $cache.per_htlc.iter() {
 209                                         htlc.write(writer)?;
 210                                         if let &Some(ref their_sig) = sig {
 211                                                 1u8.write(writer)?;
 212                                                 writer.write_all(&their_sig.serialize_compact())?;
 213                                         } else {
 214                                                 0u8.write(writer)?;
 215                                         }
 216                                 }
 217                         }
 218                 }
 219
 220                 if let Some(ref current) = self.current_htlc_cache {
 221                         writer.write_all(&[1; 1])?;
 222                         serialize_htlc_cache!(current);
 223                 } else {
 224                         writer.write_all(&[0; 1])?;
 225                 }
 226
 227                 if let Some(ref prev) = self.prev_htlc_cache {
 228                         writer.write_all(&[1; 1])?;
 229                         serialize_htlc_cache!(prev);
 230                 } else {
 231                         writer.write_all(&[0; 1])?;
 232                 }
 233
 234                 self.key_storage.write(writer)?;
 235
 236                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 237                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 238                         ancestor_claim_txid.write(writer)?;
 239                         claim_tx_data.write(writer)?;
 240                 }
 241
 242                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 243                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 244                         outp.write(writer)?;
 245                         claim_and_height.0.write(writer)?;
 246                         claim_and_height.1.write(writer)?;
 247                 }
 248
 249                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 250                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 251                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 252                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 253                         for ev in events.iter() {
 254                                 match *ev {
 255                                         OnchainEvent::Claim { ref claim_request } => {
 256                                                 writer.write_all(&[0; 1])?;
 257                                                 claim_request.write(writer)?;
 258                                         },
 259                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 260                                                 writer.write_all(&[1; 1])?;
 261                                                 outpoint.write(writer)?;
 262                                                 input_material.write(writer)?;
 263                                         }
 264                                 }
 265                         }
 266                 }
 267                 Ok(())
 268         }
 269 }
 270
 271 impl<ChanSigner: ChannelKeys + Readable> ReadableArgs<Arc<Logger>> for OnchainTxHandler<ChanSigner> {
 272         fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
 273                 let destination_script = Readable::read(reader)?;
 274                 let funding_redeemscript = Readable::read(reader)?;
 275                 let local_commitment = Readable::read(reader)?;
 276                 let prev_local_commitment = Readable::read(reader)?;
 277
 278                 macro_rules! read_htlc_cache {
 279                         () => {
 280                                 {
 281                                         let local_keys = Readable::read(reader)?;
 282                                         let feerate_per_kw = Readable::read(reader)?;
 283                                         let htlcs_count: u64 = Readable::read(reader)?;
 284                                         let mut per_htlc = HashMap::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
 285                                         for _ in 0..htlcs_count {
 286                                                 let htlc: HTLCOutputInCommitment = Readable::read(reader)?;
 287                                                 let sigs = match <u8 as Readable>::read(reader)? {
 288                                                         0 => None,
 289                                                         1 => Some(Readable::read(reader)?),
 290                                                         _ => return Err(DecodeError::InvalidValue),
 291                                                 };
 292                                                 per_htlc.insert(htlc.transaction_output_index.unwrap(), (htlc, sigs));
 293                                         }
 294                                         HTLCTxCache {
 295                                                 local_keys,
 296                                                 feerate_per_kw,
 297                                                 per_htlc
 298                                         }
 299                                 }
 300                         }
 301                 }
 302
 303                 let current_htlc_cache = match <u8 as Readable>::read(reader)? {
 304                         0 => None,
 305                         1 => {
 306                                 Some(read_htlc_cache!())
 307                         }
 308                         _ => return Err(DecodeError::InvalidValue),
 309                 };
 310
 311                 let prev_htlc_cache = match <u8 as Readable>::read(reader)? {
 312                         0 => None,
 313                         1 => {
 314                                 Some(read_htlc_cache!())
 315                         }
 316                         _ => return Err(DecodeError::InvalidValue),
 317                 };
 318
 319                 let key_storage = Readable::read(reader)?;
 320
 321                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 322                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 323                 for _ in 0..pending_claim_requests_len {
 324                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 325                 }
 326
 327                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 328                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 329                 for _ in 0..claimable_outpoints_len {
 330                         let outpoint = Readable::read(reader)?;
 331                         let ancestor_claim_txid = Readable::read(reader)?;
 332                         let height = Readable::read(reader)?;
 333                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 334                 }
 335                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 336                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 337                 for _ in 0..waiting_threshold_conf_len {
 338                         let height_target = Readable::read(reader)?;
 339                         let events_len: u64 = Readable::read(reader)?;
 340                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 341                         for _ in 0..events_len {
 342                                 let ev = match <u8 as Readable>::read(reader)? {
 343                                         0 => {
 344                                                 let claim_request = Readable::read(reader)?;
 345                                                 OnchainEvent::Claim {
 346                                                         claim_request
 347                                                 }
 348                                         },
 349                                         1 => {
 350                                                 let outpoint = Readable::read(reader)?;
 351                                                 let input_material = Readable::read(reader)?;
 352                                                 OnchainEvent::ContentiousOutpoint {
 353                                                         outpoint,
 354                                                         input_material
 355                                                 }
 356                                         }
 357                                         _ => return Err(DecodeError::InvalidValue),
 358                                 };
 359                                 events.push(ev);
 360                         }
 361                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 362                 }
 363
 364                 Ok(OnchainTxHandler {
 365                         destination_script,
 366                         funding_redeemscript,
 367                         local_commitment,
 368                         prev_local_commitment,
 369                         current_htlc_cache,
 370                         prev_htlc_cache,
 371                         key_storage,
 372                         claimable_outpoints,
 373                         pending_claim_requests,
 374                         onchain_events_waiting_threshold_conf,
 375                         secp_ctx: Secp256k1::new(),
 376                         logger,
 377                 })
 378         }
 379 }
 380
 381 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 382         pub(super) fn new(destination_script: Script, keys: ChanSigner, funding_redeemscript: Script, logger: Arc<Logger>) -> Self {
 383
 384                 let key_storage = keys;
 385
 386                 OnchainTxHandler {
 387                         destination_script,
 388                         funding_redeemscript,
 389                         local_commitment: None,
 390                         prev_local_commitment: None,
 391                         current_htlc_cache: None,
 392                         prev_htlc_cache: None,
 393                         key_storage,
 394                         pending_claim_requests: HashMap::new(),
 395                         claimable_outpoints: HashMap::new(),
 396                         onchain_events_waiting_threshold_conf: HashMap::new(),
 397
 398                         secp_ctx: Secp256k1::new(),
 399                         logger,
 400                 }
 401         }
 402
 403         pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
 404                 let mut tx_weight = 2; // count segwit flags
 405                 for inp in inputs {
 406                         // We use expected weight (and not actual) as signatures and time lock delays may vary
 407                         tx_weight +=  match inp {
 408                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 409                                 &InputDescriptors::RevokedOfferedHTLC => {
 410                                         1 + 1 + 73 + 1 + 33 + 1 + 133
 411                                 },
 412                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 413                                 &InputDescriptors::RevokedReceivedHTLC => {
 414                                         1 + 1 + 73 + 1 + 33 + 1 + 139
 415                                 },
 416                                 // number_of_witness_elements + sig_length + remotehtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
 417                                 &InputDescriptors::OfferedHTLC => {
 418                                         1 + 1 + 73 + 1 + 32 + 1 + 133
 419                                 },
 420                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 421                                 &InputDescriptors::ReceivedHTLC => {
 422                                         1 + 1 + 73 + 1 + 1 + 1 + 139
 423                                 },
 424                                 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
 425                                 &InputDescriptors::RevokedOutput => {
 426                                         1 + 1 + 73 + 1 + 1 + 1 + 77
 427                                 },
 428                         };
 429                 }
 430                 tx_weight
 431         }
 432
 433         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 434         /// 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
 435         /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
 436         /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
 437         /// frequency of the bump and so increase our bets of success.
 438         fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
 439                 if timelock_expiration <= current_height + 3 {
 440                         return current_height + 1
 441                 } else if timelock_expiration - current_height <= 15 {
 442                         return current_height + 3
 443                 }
 444                 current_height + 15
 445         }
 446
 447         /// 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
 448         /// (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.
 449         fn generate_claim_tx<F: Deref>(&self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(Option<u32>, u64, Transaction)>
 450                 where F::Target: FeeEstimator
 451         {
 452                 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
 453                 let mut inputs = Vec::new();
 454                 for outp in cached_claim_datas.per_input_material.keys() {
 455                         log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
 456                         inputs.push(TxIn {
 457                                 previous_output: *outp,
 458                                 script_sig: Script::new(),
 459                                 sequence: 0xfffffffd,
 460                                 witness: Vec::new(),
 461                         });
 462                 }
 463                 let mut bumped_tx = Transaction {
 464                         version: 2,
 465                         lock_time: 0,
 466                         input: inputs,
 467                         output: vec![TxOut {
 468                                 script_pubkey: self.destination_script.clone(),
 469                                 value: 0
 470                         }],
 471                 };
 472
 473                 macro_rules! RBF_bump {
 474                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 475                                 {
 476                                         let mut used_feerate;
 477                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 478                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 479                                                 let mut value = $amount;
 480                                                 if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
 481                                                         // Overflow check is done in subtract_high_prio_fee
 482                                                         $amount - value
 483                                                 } else {
 484                                                         log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 485                                                         return None;
 486                                                 }
 487                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 488                                         } else {
 489                                                 let fee = $old_feerate * $predicted_weight / 750;
 490                                                 if $amount <= fee {
 491                                                         log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 492                                                         return None;
 493                                                 }
 494                                                 fee
 495                                         };
 496
 497                                         let previous_fee = $old_feerate * $predicted_weight / 1000;
 498                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
 499                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 500                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 501                                         //      * 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.
 502                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 503                                                 new_fee + previous_fee + min_relay_fee - new_fee
 504                                         } else {
 505                                                 new_fee
 506                                         };
 507                                         Some((new_fee, new_fee * 1000 / $predicted_weight))
 508                                 }
 509                         }
 510                 }
 511
 512                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 513                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 514                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 515                 let mut inputs_witnesses_weight = 0;
 516                 let mut amt = 0;
 517                 let mut dynamic_fee = true;
 518                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 519                         match per_outp_material {
 520                                 &InputMaterial::Revoked { ref witness_script, ref is_htlc, ref amount, .. } => {
 521                                         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!() });
 522                                         amt += *amount;
 523                                 },
 524                                 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
 525                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 526                                         amt += *amount;
 527                                 },
 528                                 &InputMaterial::LocalHTLC { .. } => { return None; }
 529                                 &InputMaterial::Funding { .. } => {
 530                                         dynamic_fee = false;
 531                                 }
 532                         }
 533                 }
 534
 535                 if dynamic_fee {
 536                         let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
 537                         let mut new_feerate;
 538                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 539                         if cached_claim_datas.feerate_previous != 0 {
 540                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
 541                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 542                                         if new_fee > amt {
 543                                                 bumped_tx.output[0].value = 0;
 544                                         } else {
 545                                                 bumped_tx.output[0].value = amt - new_fee;
 546                                         }
 547                                         new_feerate = feerate;
 548                                 } else { return None; }
 549                         } else {
 550                                 if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
 551                                         bumped_tx.output[0].value = amt;
 552                                 } else { return None; }
 553                         }
 554                         assert!(new_feerate != 0);
 555
 556                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 557                                 match per_outp_material {
 558                                         &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref is_htlc, ref amount } => {
 559                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 560                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 561                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 562                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 563                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 564                                                 if *is_htlc {
 565                                                         bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
 566                                                 } else {
 567                                                         bumped_tx.input[i].witness.push(vec!(1));
 568                                                 }
 569                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 570                                                 log_trace!(self, "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);
 571                                         },
 572                                         &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
 573                                                 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
 574                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 575                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 576                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 577                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 578                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 579                                                 if let &Some(preimage) = preimage {
 580                                                         bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
 581                                                 } else {
 582                                                         bumped_tx.input[i].witness.push(vec![]);
 583                                                 }
 584                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 585                                                 log_trace!(self, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);
 586                                         },
 587                                         _ => unreachable!()
 588                                 }
 589                         }
 590                         log_trace!(self, "...with timer {}", new_timer.unwrap());
 591                         assert!(predicted_weight >= bumped_tx.get_weight());
 592                         return Some((new_timer, new_feerate, bumped_tx))
 593                 } else {
 594                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 595                                 match per_outp_material {
 596                                         &InputMaterial::LocalHTLC { .. } => {
 597                                                 //TODO : Given that Local Commitment Transaction and HTLC-Timeout/HTLC-Success are counter-signed by peer, we can't
 598                                                 // RBF them. Need a Lightning specs change and package relay modification :
 599                                                 // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
 600                                                 return None;
 601                                         },
 602                                         &InputMaterial::Funding { ref channel_value } => {
 603                                                 if self.local_commitment.is_some() {
 604                                                         let mut local_commitment = self.local_commitment.clone().unwrap();
 605                                                         self.key_storage.sign_local_commitment(&mut local_commitment, &self.funding_redeemscript, *channel_value, &self.secp_ctx);
 606                                                         let signed_tx = local_commitment.with_valid_witness().clone();
 607                                                         let mut amt_outputs = 0;
 608                                                         for outp in signed_tx.output.iter() {
 609                                                                 amt_outputs += outp.value;
 610                                                         }
 611                                                         let feerate = (channel_value - amt_outputs) * 1000 / signed_tx.get_weight() as u64;
 612                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 613                                                         log_trace!(self, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 614                                                         return Some((None, feerate, signed_tx));
 615                                                 }
 616                                         }
 617                                         _ => unreachable!()
 618                                 }
 619                         }
 620                 }
 621                 None
 622         }
 623
 624         pub(super) fn block_connected<B: Deref, F: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<ClaimRequest>, height: u32, broadcaster: B, fee_estimator: F)
 625                 where B::Target: BroadcasterInterface,
 626                       F::Target: FeeEstimator
 627         {
 628                 log_trace!(self, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 629                 let mut new_claims = Vec::new();
 630                 let mut aggregated_claim = HashMap::new();
 631                 let mut aggregated_soonest = ::std::u32::MAX;
 632
 633                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 634                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 635                 for req in claimable_outpoints {
 636                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 637                         if let Some(_) = self.claimable_outpoints.get(&req.outpoint) { log_trace!(self, "Bouncing off outpoint {}:{}, already registered its claiming request", req.outpoint.txid, req.outpoint.vout); } else {
 638                                 log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 639                                 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
 640                                         let mut single_input = HashMap::new();
 641                                         single_input.insert(req.outpoint, req.witness_data);
 642                                         new_claims.push((req.absolute_timelock, single_input));
 643                                 } else {
 644                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 645                                         if req.absolute_timelock < aggregated_soonest {
 646                                                 aggregated_soonest = req.absolute_timelock;
 647                                         }
 648                                 }
 649                         }
 650                 }
 651                 new_claims.push((aggregated_soonest, aggregated_claim));
 652
 653                 // Generate claim transactions and track them to bump if necessary at
 654                 // height timer expiration (i.e in how many blocks we're going to take action).
 655                 for claim in new_claims {
 656                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock: claim.0, per_input_material: claim.1.clone() };
 657                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 658                                 claim_material.height_timer = new_timer;
 659                                 claim_material.feerate_previous = new_feerate;
 660                                 let txid = tx.txid();
 661                                 self.pending_claim_requests.insert(txid, claim_material);
 662                                 for k in claim.1.keys() {
 663                                         log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
 664                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 665                                 }
 666                                 log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
 667                                 broadcaster.broadcast_transaction(&tx);
 668                         }
 669                 }
 670
 671                 let mut bump_candidates = HashSet::new();
 672                 for tx in txn_matched {
 673                         // Scan all input to verify is one of the outpoint spent is of interest for us
 674                         let mut claimed_outputs_material = Vec::new();
 675                         for inp in &tx.input {
 676                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 677                                         // If outpoint has claim request pending on it...
 678                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 679                                                 //... we need to verify equality between transaction outpoints and claim request
 680                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 681                                                 // by us.
 682                                                 let mut set_equality = true;
 683                                                 if claim_material.per_input_material.len() != tx.input.len() {
 684                                                         set_equality = false;
 685                                                 } else {
 686                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 687                                                                 if *claim_inp != tx_inp.previous_output {
 688                                                                         set_equality = false;
 689                                                                 }
 690                                                         }
 691                                                 }
 692
 693                                                 macro_rules! clean_claim_request_after_safety_delay {
 694                                                         () => {
 695                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 696                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 697                                                                         hash_map::Entry::Occupied(mut entry) => {
 698                                                                                 if !entry.get().contains(&new_event) {
 699                                                                                         entry.get_mut().push(new_event);
 700                                                                                 }
 701                                                                         },
 702                                                                         hash_map::Entry::Vacant(entry) => {
 703                                                                                 entry.insert(vec![new_event]);
 704                                                                         }
 705                                                                 }
 706                                                         }
 707                                                 }
 708
 709                                                 // If this is our transaction (or our counterparty spent all the outputs
 710                                                 // before we could anyway with same inputs order than us), wait for
 711                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 712                                                 if set_equality {
 713                                                         clean_claim_request_after_safety_delay!();
 714                                                 } else { // If false, generate new claim request with update outpoint set
 715                                                         let mut at_least_one_drop = false;
 716                                                         for input in tx.input.iter() {
 717                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 718                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 719                                                                         at_least_one_drop = true;
 720                                                                 }
 721                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 722                                                                 if claim_material.per_input_material.is_empty() {
 723                                                                         clean_claim_request_after_safety_delay!();
 724                                                                 }
 725                                                         }
 726                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 727                                                         if at_least_one_drop {
 728                                                                 bump_candidates.insert(first_claim_txid_height.0.clone());
 729                                                         }
 730                                                 }
 731                                                 break; //No need to iterate further, either tx is our or their
 732                                         } else {
 733                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 734                                         }
 735                                 }
 736                         }
 737                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 738                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 739                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 740                                         hash_map::Entry::Occupied(mut entry) => {
 741                                                 if !entry.get().contains(&new_event) {
 742                                                         entry.get_mut().push(new_event);
 743                                                 }
 744                                         },
 745                                         hash_map::Entry::Vacant(entry) => {
 746                                                 entry.insert(vec![new_event]);
 747                                         }
 748                                 }
 749                         }
 750                 }
 751
 752                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 753                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 754                         for ev in events {
 755                                 match ev {
 756                                         OnchainEvent::Claim { claim_request } => {
 757                                                 // We may remove a whole set of claim outpoints here, as these one may have
 758                                                 // been aggregated in a single tx and claimed so atomically
 759                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 760                                                         for outpoint in bump_material.per_input_material.keys() {
 761                                                                 self.claimable_outpoints.remove(&outpoint);
 762                                                         }
 763                                                 }
 764                                         },
 765                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 766                                                 self.claimable_outpoints.remove(&outpoint);
 767                                         }
 768                                 }
 769                         }
 770                 }
 771
 772                 // Check if any pending claim request must be rescheduled
 773                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 774                         if let Some(h) = claim_data.height_timer {
 775                                 if h == height {
 776                                         bump_candidates.insert(*first_claim_txid);
 777                                 }
 778                         }
 779                 }
 780
 781                 // Build, bump and rebroadcast tx accordingly
 782                 log_trace!(self, "Bumping {} candidates", bump_candidates.len());
 783                 for first_claim_txid in bump_candidates.iter() {
 784                         if let Some((new_timer, new_feerate)) = {
 785                                 if let Some(claim_material) = self.pending_claim_requests.get(first_claim_txid) {
 786                                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 787                                                 log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
 788                                                 broadcaster.broadcast_transaction(&bump_tx);
 789                                                 Some((new_timer, new_feerate))
 790                                         } else { None }
 791                                 } else { unreachable!(); }
 792                         } {
 793                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 794                                         claim_material.height_timer = new_timer;
 795                                         claim_material.feerate_previous = new_feerate;
 796                                 } else { unreachable!(); }
 797                         }
 798                 }
 799         }
 800
 801         pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
 802                 where B::Target: BroadcasterInterface,
 803                       F::Target: FeeEstimator
 804         {
 805                 let mut bump_candidates = HashMap::new();
 806                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 807                         //- our claim tx on a commitment tx output
 808                         //- resurect outpoint back in its claimable set and regenerate tx
 809                         for ev in events {
 810                                 match ev {
 811                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 812                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 813                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 814                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 815                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 816                                                                 // resurrected only one bump claim tx is going to be broadcast
 817                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 818                                                         }
 819                                                 }
 820                                         },
 821                                         _ => {},
 822                                 }
 823                         }
 824                 }
 825                 for (_, claim_material) in bump_candidates.iter_mut() {
 826                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 827                                 claim_material.height_timer = new_timer;
 828                                 claim_material.feerate_previous = new_feerate;
 829                                 broadcaster.broadcast_transaction(&bump_tx);
 830                         }
 831                 }
 832                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 833                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 834                 }
 835                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 836                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 837                 let mut remove_request = Vec::new();
 838                 self.claimable_outpoints.retain(|_, ref v|
 839                         if v.1 == height {
 840                         remove_request.push(v.0.clone());
 841                         false
 842                         } else { true });
 843                 for req in remove_request {
 844                         self.pending_claim_requests.remove(&req);
 845                 }
 846         }
 847
 848         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction, local_keys: chan_utils::TxCreationKeys, feerate_per_kw: u64, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), ()> {
 849                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 850                 // commitment transaction has been signed due to an event (either block height for
 851                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 852                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 853                 // for the aformentionned signed transaction.
 854                 if let Some(ref local_commitment) = self.local_commitment {
 855                         if local_commitment.has_local_sig() { return Err(()) }
 856                 }
 857                 self.prev_local_commitment = self.local_commitment.take();
 858                 self.local_commitment = Some(tx);
 859                 self.prev_htlc_cache = self.current_htlc_cache.take();
 860                 let mut per_htlc = HashMap::with_capacity(htlc_outputs.len());
 861                 for htlc in htlc_outputs {
 862                         if htlc.0.transaction_output_index.is_some() { // Discard dust HTLC as we will never have to generate onchain tx for them
 863                                 per_htlc.insert(htlc.0.transaction_output_index.unwrap(), (htlc.0, htlc.1));
 864                         }
 865                 }
 866                 self.current_htlc_cache = Some(HTLCTxCache {
 867                         local_keys,
 868                         feerate_per_kw,
 869                         per_htlc
 870                 });
 871                 Ok(())
 872         }
 873
 874         pub(super) fn get_fully_signed_local_tx(&mut self, channel_value_satoshis: u64) -> Option<Transaction> {
 875                 if let Some(ref mut local_commitment) = self.local_commitment {
 876                         self.key_storage.sign_local_commitment(local_commitment, &self.funding_redeemscript, channel_value_satoshis, &self.secp_ctx);
 877                         return Some(local_commitment.with_valid_witness().clone());
 878                 }
 879                 None
 880         }
 881
 882         #[cfg(test)]
 883         pub(super) fn get_fully_signed_copy_local_tx(&mut self, channel_value_satoshis: u64) -> Option<Transaction> {
 884                 if let Some(ref mut local_commitment) = self.local_commitment {
 885                         let mut local_commitment = local_commitment.clone();
 886                         self.key_storage.unsafe_sign_local_commitment(&mut local_commitment, &self.funding_redeemscript, channel_value_satoshis, &self.secp_ctx);
 887                         return Some(local_commitment.with_valid_witness().clone());
 888                 }
 889                 None
 890         }
 891 }