_ 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;
  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::PaymentPreimage;
  19 use ln::chan_utils::{HTLCType, LocalCommitmentTransaction};
  20 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
  21 use chain::keysinterface::ChannelKeys;
  22 use util::logger::Logger;
  23 use util::ser::{ReadableArgs, Readable, Writer, Writeable};
  24 use util::byte_utils;
  25
  26 use std::collections::{HashMap, hash_map};
  27 use std::sync::Arc;
  28 use std::cmp;
  29 use std::ops::Deref;
  30
  31 const MAX_ALLOC_SIZE: usize = 64*1024;
  32
  33 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
  34 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
  35 #[derive(Clone, PartialEq)]
  36 enum OnchainEvent {
  37         /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
  38         /// bump-txn candidate buffer.
  39         Claim {
  40                 claim_request: Sha256dHash,
  41         },
  42         /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
  43         /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
  44         /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
  45         ContentiousOutpoint {
  46                 outpoint: BitcoinOutPoint,
  47                 input_material: InputMaterial,
  48         }
  49 }
  50
  51 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
  52 #[derive(Clone, PartialEq)]
  53 pub struct ClaimTxBumpMaterial {
  54         // At every block tick, used to check if pending claiming tx is taking too
  55         // much time for confirmation and we need to bump it.
  56         height_timer: Option<u32>,
  57         // Tracked in case of reorg to wipe out now-superflous bump material
  58         feerate_previous: u64,
  59         // Soonest timelocks among set of outpoints claimed, used to compute
  60         // a priority of not feerate
  61         soonest_timelock: u32,
  62         // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
  63         per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
  64 }
  65
  66 impl Writeable for ClaimTxBumpMaterial  {
  67         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
  68                 self.height_timer.write(writer)?;
  69                 writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
  70                 writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
  71                 writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
  72                 for (outp, tx_material) in self.per_input_material.iter() {
  73                         outp.write(writer)?;
  74                         tx_material.write(writer)?;
  75                 }
  76                 Ok(())
  77         }
  78 }
  79
  80 impl Readable for ClaimTxBumpMaterial {
  81         fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
  82                 let height_timer = Readable::read(reader)?;
  83                 let feerate_previous = Readable::read(reader)?;
  84                 let soonest_timelock = Readable::read(reader)?;
  85                 let per_input_material_len: u64 = Readable::read(reader)?;
  86                 let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
  87                 for _ in 0 ..per_input_material_len {
  88                         let outpoint = Readable::read(reader)?;
  89                         let input_material = Readable::read(reader)?;
  90                         per_input_material.insert(outpoint, input_material);
  91                 }
  92                 Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
  93         }
  94 }
  95
  96 #[derive(PartialEq)]
  97 pub(super) enum InputDescriptors {
  98         RevokedOfferedHTLC,
  99         RevokedReceivedHTLC,
 100         OfferedHTLC,
 101         ReceivedHTLC,
 102         RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
 103 }
 104
 105 macro_rules! subtract_high_prio_fee {
 106         ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
 107                 {
 108                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
 109                         let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
 110                         if $value <= fee {
 111                                 $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
 112                                 fee = $used_feerate * ($predicted_weight as u64) / 1000;
 113                                 if $value <= fee {
 114                                         $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
 115                                         fee = $used_feerate * ($predicted_weight as u64) / 1000;
 116                                         if $value <= fee {
 117                                                 log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
 118                                                         fee, $value);
 119                                                 false
 120                                         } else {
 121                                                 log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 122                                                         $value);
 123                                                 $value -= fee;
 124                                                 true
 125                                         }
 126                                 } else {
 127                                         log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
 128                                                 $value);
 129                                         $value -= fee;
 130                                         true
 131                                 }
 132                         } else {
 133                                 $value -= fee;
 134                                 true
 135                         }
 136                 }
 137         }
 138 }
 139
 140
 141 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 142 /// do RBF bumping if possible.
 143 pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 144         destination_script: Script,
 145         local_commitment: Option<LocalCommitmentTransaction>,
 146         prev_local_commitment: Option<LocalCommitmentTransaction>,
 147         local_csv: u16,
 148
 149         key_storage: ChanSigner,
 150
 151         // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
 152         // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
 153         // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
 154         // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
 155         // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
 156         // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
 157         // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
 158         // we need to regenerate new claim request with reduced set of still-claimable outpoints.
 159         // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
 160         // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
 161         // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
 162         #[cfg(test)] // Used in functional_test to verify sanitization
 163         pub pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
 164         #[cfg(not(test))]
 165         pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
 166
 167         // Used to link outpoints claimed in a connected block to a pending claim request.
 168         // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
 169         // Value is (pending claim request identifier, confirmation_block), identifier
 170         // is txid of the initial claiming transaction and is immutable until outpoint is
 171         // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
 172         // block with output gets disconnected.
 173         #[cfg(test)] // Used in functional_test to verify sanitization
 174         pub claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
 175         #[cfg(not(test))]
 176         claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
 177
 178         onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
 179
 180         secp_ctx: Secp256k1<secp256k1::All>,
 181         logger: Arc<Logger>
 182 }
 183
 184 impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 185         pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 186                 self.destination_script.write(writer)?;
 187                 self.local_commitment.write(writer)?;
 188                 self.prev_local_commitment.write(writer)?;
 189
 190                 self.local_csv.write(writer)?;
 191
 192                 self.key_storage.write(writer)?;
 193
 194                 writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 195                 for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 196                         ancestor_claim_txid.write(writer)?;
 197                         claim_tx_data.write(writer)?;
 198                 }
 199
 200                 writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
 201                 for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
 202                         outp.write(writer)?;
 203                         claim_and_height.0.write(writer)?;
 204                         claim_and_height.1.write(writer)?;
 205                 }
 206
 207                 writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
 208                 for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
 209                         writer.write_all(&byte_utils::be32_to_array(**target))?;
 210                         writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
 211                         for ev in events.iter() {
 212                                 match *ev {
 213                                         OnchainEvent::Claim { ref claim_request } => {
 214                                                 writer.write_all(&[0; 1])?;
 215                                                 claim_request.write(writer)?;
 216                                         },
 217                                         OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
 218                                                 writer.write_all(&[1; 1])?;
 219                                                 outpoint.write(writer)?;
 220                                                 input_material.write(writer)?;
 221                                         }
 222                                 }
 223                         }
 224                 }
 225                 Ok(())
 226         }
 227 }
 228
 229 impl<ChanSigner: ChannelKeys + Readable> ReadableArgs<Arc<Logger>> for OnchainTxHandler<ChanSigner> {
 230         fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
 231                 let destination_script = Readable::read(reader)?;
 232
 233                 let local_commitment = Readable::read(reader)?;
 234                 let prev_local_commitment = Readable::read(reader)?;
 235
 236                 let local_csv = Readable::read(reader)?;
 237
 238                 let key_storage = Readable::read(reader)?;
 239
 240                 let pending_claim_requests_len: u64 = Readable::read(reader)?;
 241                 let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 242                 for _ in 0..pending_claim_requests_len {
 243                         pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
 244                 }
 245
 246                 let claimable_outpoints_len: u64 = Readable::read(reader)?;
 247                 let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 248                 for _ in 0..claimable_outpoints_len {
 249                         let outpoint = Readable::read(reader)?;
 250                         let ancestor_claim_txid = Readable::read(reader)?;
 251                         let height = Readable::read(reader)?;
 252                         claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 253                 }
 254                 let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
 255                 let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 256                 for _ in 0..waiting_threshold_conf_len {
 257                         let height_target = Readable::read(reader)?;
 258                         let events_len: u64 = Readable::read(reader)?;
 259                         let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
 260                         for _ in 0..events_len {
 261                                 let ev = match <u8 as Readable>::read(reader)? {
 262                                         0 => {
 263                                                 let claim_request = Readable::read(reader)?;
 264                                                 OnchainEvent::Claim {
 265                                                         claim_request
 266                                                 }
 267                                         },
 268                                         1 => {
 269                                                 let outpoint = Readable::read(reader)?;
 270                                                 let input_material = Readable::read(reader)?;
 271                                                 OnchainEvent::ContentiousOutpoint {
 272                                                         outpoint,
 273                                                         input_material
 274                                                 }
 275                                         }
 276                                         _ => return Err(DecodeError::InvalidValue),
 277                                 };
 278                                 events.push(ev);
 279                         }
 280                         onchain_events_waiting_threshold_conf.insert(height_target, events);
 281                 }
 282
 283                 Ok(OnchainTxHandler {
 284                         destination_script,
 285                         local_commitment,
 286                         prev_local_commitment,
 287                         local_csv,
 288                         key_storage,
 289                         claimable_outpoints,
 290                         pending_claim_requests,
 291                         onchain_events_waiting_threshold_conf,
 292                         secp_ctx: Secp256k1::new(),
 293                         logger,
 294                 })
 295         }
 296 }
 297
 298 impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 299         pub(super) fn new(destination_script: Script, keys: ChanSigner, local_csv: u16, logger: Arc<Logger>) -> Self {
 300
 301                 let key_storage = keys;
 302
 303                 OnchainTxHandler {
 304                         destination_script,
 305                         local_commitment: None,
 306                         prev_local_commitment: None,
 307                         local_csv,
 308                         key_storage,
 309                         pending_claim_requests: HashMap::new(),
 310                         claimable_outpoints: HashMap::new(),
 311                         onchain_events_waiting_threshold_conf: HashMap::new(),
 312
 313                         secp_ctx: Secp256k1::new(),
 314                         logger,
 315                 }
 316         }
 317
 318         pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
 319                 let mut tx_weight = 2; // count segwit flags
 320                 for inp in inputs {
 321                         // We use expected weight (and not actual) as signatures and time lock delays may vary
 322                         tx_weight +=  match inp {
 323                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 324                                 &InputDescriptors::RevokedOfferedHTLC => {
 325                                         1 + 1 + 73 + 1 + 33 + 1 + 133
 326                                 },
 327                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 328                                 &InputDescriptors::RevokedReceivedHTLC => {
 329                                         1 + 1 + 73 + 1 + 33 + 1 + 139
 330                                 },
 331                                 // number_of_witness_elements + sig_length + remotehtlc_sig  + preimage_length + preimage + witness_script_length + witness_script
 332                                 &InputDescriptors::OfferedHTLC => {
 333                                         1 + 1 + 73 + 1 + 32 + 1 + 133
 334                                 },
 335                                 // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
 336                                 &InputDescriptors::ReceivedHTLC => {
 337                                         1 + 1 + 73 + 1 + 1 + 1 + 139
 338                                 },
 339                                 // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
 340                                 &InputDescriptors::RevokedOutput => {
 341                                         1 + 1 + 73 + 1 + 1 + 1 + 77
 342                                 },
 343                         };
 344                 }
 345                 tx_weight
 346         }
 347
 348         /// In LN, output claimed are time-sensitive, which means we have to spend them before reaching some timelock expiration. At in-channel
 349         /// 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
 350         /// height than once reached we should generate a new bumped "version" of the claim tx to be sure than we safely claim outputs before
 351         /// than our counterparty can do it too. If timelock expires soon, height timer is going to be scale down in consequence to increase
 352         /// frequency of the bump and so increase our bets of success.
 353         fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
 354                 if timelock_expiration <= current_height + 3 {
 355                         return current_height + 1
 356                 } else if timelock_expiration - current_height <= 15 {
 357                         return current_height + 3
 358                 }
 359                 current_height + 15
 360         }
 361
 362         /// 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
 363         /// (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.
 364         fn generate_claim_tx<F: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(Option<u32>, u64, Transaction)>
 365                 where F::Target: FeeEstimator
 366         {
 367                 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
 368                 let mut inputs = Vec::new();
 369                 for outp in cached_claim_datas.per_input_material.keys() {
 370                         log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
 371                         inputs.push(TxIn {
 372                                 previous_output: *outp,
 373                                 script_sig: Script::new(),
 374                                 sequence: 0xfffffffd,
 375                                 witness: Vec::new(),
 376                         });
 377                 }
 378                 let mut bumped_tx = Transaction {
 379                         version: 2,
 380                         lock_time: 0,
 381                         input: inputs,
 382                         output: vec![TxOut {
 383                                 script_pubkey: self.destination_script.clone(),
 384                                 value: 0
 385                         }],
 386                 };
 387
 388                 macro_rules! RBF_bump {
 389                         ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
 390                                 {
 391                                         let mut used_feerate;
 392                                         // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
 393                                         let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
 394                                                 let mut value = $amount;
 395                                                 if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
 396                                                         // Overflow check is done in subtract_high_prio_fee
 397                                                         $amount - value
 398                                                 } else {
 399                                                         log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
 400                                                         return None;
 401                                                 }
 402                                         // ...else just increase the previous feerate by 25% (because that's a nice number)
 403                                         } else {
 404                                                 let fee = $old_feerate * $predicted_weight / 750;
 405                                                 if $amount <= fee {
 406                                                         log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
 407                                                         return None;
 408                                                 }
 409                                                 fee
 410                                         };
 411
 412                                         let previous_fee = $old_feerate * $predicted_weight / 1000;
 413                                         let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
 414                                         // BIP 125 Opt-in Full Replace-by-Fee Signaling
 415                                         //      * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
 416                                         //      * 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.
 417                                         let new_fee = if new_fee < previous_fee + min_relay_fee {
 418                                                 new_fee + previous_fee + min_relay_fee - new_fee
 419                                         } else {
 420                                                 new_fee
 421                                         };
 422                                         Some((new_fee, new_fee * 1000 / $predicted_weight))
 423                                 }
 424                         }
 425                 }
 426
 427                 // Compute new height timer to decide when we need to regenerate a new bumped version of the claim tx (if we
 428                 // didn't receive confirmation of it before, or not enough reorg-safe depth on top of it).
 429                 let new_timer = Some(Self::get_height_timer(height, cached_claim_datas.soonest_timelock));
 430                 let mut inputs_witnesses_weight = 0;
 431                 let mut amt = 0;
 432                 let mut dynamic_fee = true;
 433                 for per_outp_material in cached_claim_datas.per_input_material.values() {
 434                         match per_outp_material {
 435                                 &InputMaterial::Revoked { ref witness_script, ref is_htlc, ref amount, .. } => {
 436                                         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!() });
 437                                         amt += *amount;
 438                                 },
 439                                 &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
 440                                         inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
 441                                         amt += *amount;
 442                                 },
 443                                 &InputMaterial::LocalHTLC { .. } => {
 444                                         dynamic_fee = false;
 445                                 },
 446                                 &InputMaterial::Funding { .. } => {
 447                                         dynamic_fee = false;
 448                                 }
 449                         }
 450                 }
 451                 if dynamic_fee {
 452                         let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
 453                         let mut new_feerate;
 454                         // If old feerate is 0, first iteration of this claim, use normal fee calculation
 455                         if cached_claim_datas.feerate_previous != 0 {
 456                                 if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
 457                                         // If new computed fee is superior at the whole claimable amount burn all in fees
 458                                         if new_fee > amt {
 459                                                 bumped_tx.output[0].value = 0;
 460                                         } else {
 461                                                 bumped_tx.output[0].value = amt - new_fee;
 462                                         }
 463                                         new_feerate = feerate;
 464                                 } else { return None; }
 465                         } else {
 466                                 if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
 467                                         bumped_tx.output[0].value = amt;
 468                                 } else { return None; }
 469                         }
 470                         assert!(new_feerate != 0);
 471
 472                         for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 473                                 match per_outp_material {
 474                                         &InputMaterial::Revoked { ref witness_script, ref pubkey, ref key, ref is_htlc, ref amount } => {
 475                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 476                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 477                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 478                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 479                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 480                                                 if *is_htlc {
 481                                                         bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
 482                                                 } else {
 483                                                         bumped_tx.input[i].witness.push(vec!(1));
 484                                                 }
 485                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 486                                                 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);
 487                                         },
 488                                         &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => {
 489                                                 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
 490                                                 let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
 491                                                 let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]);
 492                                                 let sig = self.secp_ctx.sign(&sighash, &key);
 493                                                 bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
 494                                                 bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
 495                                                 if let &Some(preimage) = preimage {
 496                                                         bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
 497                                                 } else {
 498                                                         bumped_tx.input[i].witness.push(vec![]);
 499                                                 }
 500                                                 bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 501                                                 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);
 502                                         },
 503                                         _ => unreachable!()
 504                                 }
 505                         }
 506                         log_trace!(self, "...with timer {}", new_timer.unwrap());
 507                         assert!(predicted_weight >= bumped_tx.get_weight());
 508                         return Some((new_timer, new_feerate, bumped_tx))
 509                 } else {
 510                         for (_, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 511                                 match per_outp_material {
 512                                         &InputMaterial::LocalHTLC { ref preimage, ref amount } => {
 513                                                 let mut htlc_tx = None;
 514                                                 if let Some(ref mut local_commitment) = self.local_commitment {
 515                                                         if local_commitment.txid() == outp.txid {
 516                                                                 self.key_storage.sign_htlc_transaction(local_commitment, outp.vout, *preimage, self.local_csv, &self.secp_ctx);
 517                                                                 htlc_tx = local_commitment.htlc_with_valid_witness(outp.vout).clone();
 518                                                         }
 519                                                 }
 520                                                 if let Some(ref mut prev_local_commitment) = self.prev_local_commitment {
 521                                                         if prev_local_commitment.txid() == outp.txid {
 522                                                                 self.key_storage.sign_htlc_transaction(prev_local_commitment, outp.vout, *preimage, self.local_csv, &self.secp_ctx);
 523                                                                 htlc_tx = prev_local_commitment.htlc_with_valid_witness(outp.vout).clone();
 524                                                         }
 525                                                 }
 526                                                 if let Some(htlc_tx) = htlc_tx {
 527                                                         let feerate = (amount - htlc_tx.output[0].value) * 1000 / htlc_tx.get_weight() as u64;
 528                                                         // Timer set to $NEVER given we can't bump tx without anchor outputs
 529                                                         log_trace!(self, "Going to broadcast Local HTLC-{} claiming HTLC output {} from {}...", if preimage.is_some() { "Success" } else { "Timeout" }, outp.vout, outp.txid);
 530                                                         return Some((None, feerate, htlc_tx));
 531                                                 }
 532                                                 return None;
 533                                         },
 534                                         &InputMaterial::Funding {} => {
 535                                                 let signed_tx = self.get_fully_signed_local_tx().unwrap();
 536                                                 // Timer set to $NEVER given we can't bump tx without anchor outputs
 537                                                 log_trace!(self, "Going to broadcast Local Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
 538                                                 return Some((None, self.local_commitment.as_ref().unwrap().feerate_per_kw, signed_tx));
 539                                         }
 540                                         _ => unreachable!()
 541                                 }
 542                         }
 543                 }
 544                 None
 545         }
 546
 547         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)
 548                 where B::Target: BroadcasterInterface,
 549                       F::Target: FeeEstimator
 550         {
 551                 log_trace!(self, "Block at height {} connected with {} claim requests", height, claimable_outpoints.len());
 552                 let mut new_claims = Vec::new();
 553                 let mut aggregated_claim = HashMap::new();
 554                 let mut aggregated_soonest = ::std::u32::MAX;
 555
 556                 // Try to aggregate outputs if their timelock expiration isn't imminent (absolute_timelock
 557                 // <= CLTV_SHARED_CLAIM_BUFFER) and they don't require an immediate nLockTime (aggregable).
 558                 for req in claimable_outpoints {
 559                         // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
 560                         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 {
 561                                 log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", req.absolute_timelock, height + CLTV_SHARED_CLAIM_BUFFER);
 562                                 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
 563                                         let mut single_input = HashMap::new();
 564                                         single_input.insert(req.outpoint, req.witness_data);
 565                                         new_claims.push((req.absolute_timelock, single_input));
 566                                 } else {
 567                                         aggregated_claim.insert(req.outpoint, req.witness_data);
 568                                         if req.absolute_timelock < aggregated_soonest {
 569                                                 aggregated_soonest = req.absolute_timelock;
 570                                         }
 571                                 }
 572                         }
 573                 }
 574                 new_claims.push((aggregated_soonest, aggregated_claim));
 575
 576                 // Generate claim transactions and track them to bump if necessary at
 577                 // height timer expiration (i.e in how many blocks we're going to take action).
 578                 for (soonest_timelock, claim) in new_claims.drain(..) {
 579                         let mut claim_material = ClaimTxBumpMaterial { height_timer: None, feerate_previous: 0, soonest_timelock, per_input_material: claim };
 580                         if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 581                                 claim_material.height_timer = new_timer;
 582                                 claim_material.feerate_previous = new_feerate;
 583                                 let txid = tx.txid();
 584                                 for k in claim_material.per_input_material.keys() {
 585                                         log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
 586                                         self.claimable_outpoints.insert(k.clone(), (txid, height));
 587                                 }
 588                                 self.pending_claim_requests.insert(txid, claim_material);
 589                                 log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
 590                                 broadcaster.broadcast_transaction(&tx);
 591                         }
 592                 }
 593
 594                 let mut bump_candidates = HashMap::new();
 595                 for tx in txn_matched {
 596                         // Scan all input to verify is one of the outpoint spent is of interest for us
 597                         let mut claimed_outputs_material = Vec::new();
 598                         for inp in &tx.input {
 599                                 if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
 600                                         // If outpoint has claim request pending on it...
 601                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
 602                                                 //... we need to verify equality between transaction outpoints and claim request
 603                                                 // outpoints to know if transaction is the original claim or a bumped one issued
 604                                                 // by us.
 605                                                 let mut set_equality = true;
 606                                                 if claim_material.per_input_material.len() != tx.input.len() {
 607                                                         set_equality = false;
 608                                                 } else {
 609                                                         for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
 610                                                                 if *claim_inp != tx_inp.previous_output {
 611                                                                         set_equality = false;
 612                                                                 }
 613                                                         }
 614                                                 }
 615
 616                                                 macro_rules! clean_claim_request_after_safety_delay {
 617                                                         () => {
 618                                                                 let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
 619                                                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 620                                                                         hash_map::Entry::Occupied(mut entry) => {
 621                                                                                 if !entry.get().contains(&new_event) {
 622                                                                                         entry.get_mut().push(new_event);
 623                                                                                 }
 624                                                                         },
 625                                                                         hash_map::Entry::Vacant(entry) => {
 626                                                                                 entry.insert(vec![new_event]);
 627                                                                         }
 628                                                                 }
 629                                                         }
 630                                                 }
 631
 632                                                 // If this is our transaction (or our counterparty spent all the outputs
 633                                                 // before we could anyway with same inputs order than us), wait for
 634                                                 // ANTI_REORG_DELAY and clean the RBF tracking map.
 635                                                 if set_equality {
 636                                                         clean_claim_request_after_safety_delay!();
 637                                                 } else { // If false, generate new claim request with update outpoint set
 638                                                         let mut at_least_one_drop = false;
 639                                                         for input in tx.input.iter() {
 640                                                                 if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
 641                                                                         claimed_outputs_material.push((input.previous_output, input_material));
 642                                                                         at_least_one_drop = true;
 643                                                                 }
 644                                                                 // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
 645                                                                 if claim_material.per_input_material.is_empty() {
 646                                                                         clean_claim_request_after_safety_delay!();
 647                                                                 }
 648                                                         }
 649                                                         //TODO: recompute soonest_timelock to avoid wasting a bit on fees
 650                                                         if at_least_one_drop {
 651                                                                 bump_candidates.insert(first_claim_txid_height.0.clone(), claim_material.clone());
 652                                                         }
 653                                                 }
 654                                                 break; //No need to iterate further, either tx is our or their
 655                                         } else {
 656                                                 panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
 657                                         }
 658                                 }
 659                         }
 660                         for (outpoint, input_material) in claimed_outputs_material.drain(..) {
 661                                 let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
 662                                 match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
 663                                         hash_map::Entry::Occupied(mut entry) => {
 664                                                 if !entry.get().contains(&new_event) {
 665                                                         entry.get_mut().push(new_event);
 666                                                 }
 667                                         },
 668                                         hash_map::Entry::Vacant(entry) => {
 669                                                 entry.insert(vec![new_event]);
 670                                         }
 671                                 }
 672                         }
 673                 }
 674
 675                 // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
 676                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
 677                         for ev in events {
 678                                 match ev {
 679                                         OnchainEvent::Claim { claim_request } => {
 680                                                 // We may remove a whole set of claim outpoints here, as these one may have
 681                                                 // been aggregated in a single tx and claimed so atomically
 682                                                 if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
 683                                                         for outpoint in bump_material.per_input_material.keys() {
 684                                                                 self.claimable_outpoints.remove(&outpoint);
 685                                                         }
 686                                                 }
 687                                         },
 688                                         OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
 689                                                 self.claimable_outpoints.remove(&outpoint);
 690                                         }
 691                                 }
 692                         }
 693                 }
 694
 695                 // Check if any pending claim request must be rescheduled
 696                 for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
 697                         if let Some(h) = claim_data.height_timer {
 698                                 if h == height {
 699                                         bump_candidates.insert(*first_claim_txid, (*claim_data).clone());
 700                                 }
 701                         }
 702                 }
 703
 704                 // Build, bump and rebroadcast tx accordingly
 705                 log_trace!(self, "Bumping {} candidates", bump_candidates.len());
 706                 for (first_claim_txid, claim_material) in bump_candidates.iter() {
 707                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 708                                 log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
 709                                 broadcaster.broadcast_transaction(&bump_tx);
 710                                 if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
 711                                         claim_material.height_timer = new_timer;
 712                                         claim_material.feerate_previous = new_feerate;
 713                                 }
 714                         }
 715                 }
 716         }
 717
 718         pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
 719                 where B::Target: BroadcasterInterface,
 720                       F::Target: FeeEstimator
 721         {
 722                 let mut bump_candidates = HashMap::new();
 723                 if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
 724                         //- our claim tx on a commitment tx output
 725                         //- resurect outpoint back in its claimable set and regenerate tx
 726                         for ev in events {
 727                                 match ev {
 728                                         OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 729                                                 if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 730                                                         if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
 731                                                                 claim_material.per_input_material.insert(outpoint, input_material);
 732                                                                 // Using a HashMap guarantee us than if we have multiple outpoints getting
 733                                                                 // resurrected only one bump claim tx is going to be broadcast
 734                                                                 bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
 735                                                         }
 736                                                 }
 737                                         },
 738                                         _ => {},
 739                                 }
 740                         }
 741                 }
 742                 for (_, claim_material) in bump_candidates.iter_mut() {
 743                         if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
 744                                 claim_material.height_timer = new_timer;
 745                                 claim_material.feerate_previous = new_feerate;
 746                                 broadcaster.broadcast_transaction(&bump_tx);
 747                         }
 748                 }
 749                 for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
 750                         self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
 751                 }
 752                 //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
 753                 // right now if one of the outpoint get disconnected, just erase whole pending claim request.
 754                 let mut remove_request = Vec::new();
 755                 self.claimable_outpoints.retain(|_, ref v|
 756                         if v.1 == height {
 757                         remove_request.push(v.0.clone());
 758                         false
 759                         } else { true });
 760                 for req in remove_request {
 761                         self.pending_claim_requests.remove(&req);
 762                 }
 763         }
 764
 765         pub(super) fn provide_latest_local_tx(&mut self, tx: LocalCommitmentTransaction) -> Result<(), ()> {
 766                 // To prevent any unsafe state discrepancy between offchain and onchain, once local
 767                 // commitment transaction has been signed due to an event (either block height for
 768                 // HTLC-timeout or channel force-closure), don't allow any further update of local
 769                 // commitment transaction view to avoid delivery of revocation secret to counterparty
 770                 // for the aformentionned signed transaction.
 771                 if let Some(ref local_commitment) = self.local_commitment {
 772                         if local_commitment.has_local_sig() { return Err(()) }
 773                 }
 774                 self.prev_local_commitment = self.local_commitment.take();
 775                 self.local_commitment = Some(tx);
 776                 Ok(())
 777         }
 778
 779         //TODO: getting lastest local transactions should be infaillible and result in us "force-closing the channel", but we may
 780         // have empty local commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_funding_created,
 781         // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing
 782         // to monitor before.
 783         pub(super) fn get_fully_signed_local_tx(&mut self) -> Option<Transaction> {
 784                 if let Some(ref mut local_commitment) = self.local_commitment {
 785                         self.key_storage.sign_local_commitment(local_commitment, &self.secp_ctx);
 786                         return Some(local_commitment.with_valid_witness().clone());
 787                 }
 788                 None
 789         }
 790
 791         #[cfg(test)]
 792         pub(super) fn get_fully_signed_copy_local_tx(&mut self) -> Option<Transaction> {
 793                 if let Some(ref mut local_commitment) = self.local_commitment {
 794                         let mut local_commitment = local_commitment.clone();
 795                         self.key_storage.unsafe_sign_local_commitment(&mut local_commitment, &self.secp_ctx);
 796                         return Some(local_commitment.with_valid_witness().clone());
 797                 }
 798                 None
 799         }
 800
 801         pub(super) fn get_fully_signed_htlc_tx(&mut self, txid: Sha256dHash, htlc_index: u32, preimage: Option<PaymentPreimage>) -> Option<Transaction> {
 802                 //TODO: store preimage in OnchainTxHandler
 803                 if let Some(ref mut local_commitment) = self.local_commitment {
 804                         if local_commitment.txid() == txid {
 805                                 self.key_storage.sign_htlc_transaction(local_commitment, htlc_index, preimage, self.local_csv, &self.secp_ctx);
 806                                 return local_commitment.htlc_with_valid_witness(htlc_index).clone();
 807                         }
 808                 }
 809                 None
 810         }
 811 }