--- /dev/null
+//! The logic to build claims and bump in-flight transactions until confirmations.
+//!
+//! OnchainTxHandler objetcs are fully-part of ChannelMonitor and encapsulates all
+//! building, tracking, bumping and notifications functions.
+
+use bitcoin::blockdata::transaction::{Transaction, TxIn, TxOut, SigHashType};
+use bitcoin::blockdata::transaction::OutPoint as BitcoinOutPoint;
+use bitcoin::blockdata::script::Script;
+use bitcoin::util::bip143;
+
+use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+
+use secp256k1::Secp256k1;
+use secp256k1;
+
+use ln::msgs::DecodeError;
+use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial};
+use ln::chan_utils::HTLCType;
+use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
+use chain::keysinterface::SpendableOutputDescriptor;
+use util::logger::Logger;
+use util::ser::{ReadableArgs, Readable, Writer, Writeable};
+use util::byte_utils;
+
+use std::collections::{HashMap, hash_map, HashSet};
+use std::sync::Arc;
+use std::cmp;
+use std::ops::Deref;
+
+const MAX_ALLOC_SIZE: usize = 64*1024;
+
+/// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
+/// once they mature to enough confirmations (ANTI_REORG_DELAY)
+#[derive(Clone, PartialEq)]
+enum OnchainEvent {
+ /// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
+ /// bump-txn candidate buffer.
+ Claim {
+ claim_request: Sha256dHash,
+ },
+ /// Claim tx aggregate multiple claimable outpoints. One of the outpoint may be claimed by a remote party tx.
+ /// In this case, we need to drop the outpoint and regenerate a new claim tx. By safety, we keep tracking
+ /// the outpoint to be sure to resurect it back to the claim tx if reorgs happen.
+ ContentiousOutpoint {
+ outpoint: BitcoinOutPoint,
+ input_material: InputMaterial,
+ }
+}
+
+/// Higher-level cache structure needed to re-generate bumped claim txn if needed
+#[derive(Clone, PartialEq)]
+pub struct ClaimTxBumpMaterial {
+ // At every block tick, used to check if pending claiming tx is taking too
+ // much time for confirmation and we need to bump it.
+ height_timer: u32,
+ // Tracked in case of reorg to wipe out now-superflous bump material
+ feerate_previous: u64,
+ // Soonest timelocks among set of outpoints claimed, used to compute
+ // a priority of not feerate
+ soonest_timelock: u32,
+ // Cache of script, pubkey, sig or key to solve claimable outputs scriptpubkey.
+ per_input_material: HashMap<BitcoinOutPoint, InputMaterial>,
+}
+
+impl Writeable for ClaimTxBumpMaterial {
+ fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+ writer.write_all(&byte_utils::be32_to_array(self.height_timer))?;
+ writer.write_all(&byte_utils::be64_to_array(self.feerate_previous))?;
+ writer.write_all(&byte_utils::be32_to_array(self.soonest_timelock))?;
+ writer.write_all(&byte_utils::be64_to_array(self.per_input_material.len() as u64))?;
+ for (outp, tx_material) in self.per_input_material.iter() {
+ outp.write(writer)?;
+ tx_material.write(writer)?;
+ }
+ Ok(())
+ }
+}
+
+impl Readable for ClaimTxBumpMaterial {
+ fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+ let height_timer = Readable::read(reader)?;
+ let feerate_previous = Readable::read(reader)?;
+ let soonest_timelock = Readable::read(reader)?;
+ let per_input_material_len: u64 = Readable::read(reader)?;
+ let mut per_input_material = HashMap::with_capacity(cmp::min(per_input_material_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0 ..per_input_material_len {
+ let outpoint = Readable::read(reader)?;
+ let input_material = Readable::read(reader)?;
+ per_input_material.insert(outpoint, input_material);
+ }
+ Ok(Self { height_timer, feerate_previous, soonest_timelock, per_input_material })
+ }
+}
+
+#[derive(PartialEq)]
+pub(super) enum InputDescriptors {
+ RevokedOfferedHTLC,
+ RevokedReceivedHTLC,
+ OfferedHTLC,
+ ReceivedHTLC,
+ RevokedOutput, // either a revoked to_local output on commitment tx, a revoked HTLC-Timeout output or a revoked HTLC-Success output
+}
+
+macro_rules! subtract_high_prio_fee {
+ ($self: ident, $fee_estimator: expr, $value: expr, $predicted_weight: expr, $used_feerate: expr) => {
+ {
+ $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority);
+ let mut fee = $used_feerate * ($predicted_weight as u64) / 1000;
+ if $value <= fee {
+ $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal);
+ fee = $used_feerate * ($predicted_weight as u64) / 1000;
+ if $value <= fee {
+ $used_feerate = $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
+ fee = $used_feerate * ($predicted_weight as u64) / 1000;
+ if $value <= fee {
+ log_error!($self, "Failed to generate an on-chain punishment tx as even low priority fee ({} sat) was more than the entire claim balance ({} sat)",
+ fee, $value);
+ false
+ } else {
+ log_warn!($self, "Used low priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
+ $value);
+ $value -= fee;
+ true
+ }
+ } else {
+ log_warn!($self, "Used medium priority fee for on-chain punishment tx as high priority fee was more than the entire claim balance ({} sat)",
+ $value);
+ $value -= fee;
+ true
+ }
+ } else {
+ $value -= fee;
+ true
+ }
+ }
+ }
+}
+
+
+/// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
+/// do RBF bumping if possible.
+#[derive(Clone)]
+pub struct OnchainTxHandler {
+ destination_script: Script,
+
+ // Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
+ // it (RBF or CPFP). If an input has been part of an aggregate tx at first claim try, we need to keep it within
+ // another bumped aggregate tx to comply with RBF rules. We may have multiple claiming txn in the flight for the
+ // same set of outpoints. One of the outpoints may be spent by a transaction not issued by us. That's why at
+ // block connection we scan all inputs and if any of them is among a set of a claiming request we test for set
+ // equality between spending transaction and claim request. If true, it means transaction was one our claiming one
+ // after a security delay of 6 blocks we remove pending claim request. If false, it means transaction wasn't and
+ // we need to regenerate new claim request with reduced set of still-claimable outpoints.
+ // Key is identifier of the pending claim request, i.e the txid of the initial claiming transaction generated by
+ // us and is immutable until all outpoint of the claimable set are post-anti-reorg-delay solved.
+ // Entry is cache of elements need to generate a bumped claiming transaction (see ClaimTxBumpMaterial)
+ #[cfg(test)] // Used in functional_test to verify sanitization
+ pub pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
+ #[cfg(not(test))]
+ pending_claim_requests: HashMap<Sha256dHash, ClaimTxBumpMaterial>,
+
+ // Used to link outpoints claimed in a connected block to a pending claim request.
+ // Key is outpoint than monitor parsing has detected we have keys/scripts to claim
+ // Value is (pending claim request identifier, confirmation_block), identifier
+ // is txid of the initial claiming transaction and is immutable until outpoint is
+ // post-anti-reorg-delay solved, confirmaiton_block is used to erase entry if
+ // block with output gets disconnected.
+ #[cfg(test)] // Used in functional_test to verify sanitization
+ pub claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
+ #[cfg(not(test))]
+ claimable_outpoints: HashMap<BitcoinOutPoint, (Sha256dHash, u32)>,
+
+ onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
+
+ secp_ctx: Secp256k1<secp256k1::All>,
+ logger: Arc<Logger>
+}
+
+impl Writeable for OnchainTxHandler {
+ fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+ self.destination_script.write(writer)?;
+
+ writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
+ for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
+ ancestor_claim_txid.write(writer)?;
+ claim_tx_data.write(writer)?;
+ }
+
+ writer.write_all(&byte_utils::be64_to_array(self.claimable_outpoints.len() as u64))?;
+ for (ref outp, ref claim_and_height) in self.claimable_outpoints.iter() {
+ outp.write(writer)?;
+ claim_and_height.0.write(writer)?;
+ claim_and_height.1.write(writer)?;
+ }
+
+ writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
+ for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
+ writer.write_all(&byte_utils::be32_to_array(**target))?;
+ writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
+ for ev in events.iter() {
+ match *ev {
+ OnchainEvent::Claim { ref claim_request } => {
+ writer.write_all(&[0; 1])?;
+ claim_request.write(writer)?;
+ },
+ OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
+ writer.write_all(&[1; 1])?;
+ outpoint.write(writer)?;
+ input_material.write(writer)?;
+ }
+ }
+ }
+ }
+ Ok(())
+ }
+}
+
+impl ReadableArgs<Arc<Logger>> for OnchainTxHandler {
+ fn read<R: ::std::io::Read>(reader: &mut R, logger: Arc<Logger>) -> Result<Self, DecodeError> {
+ let destination_script = Readable::read(reader)?;
+
+ let pending_claim_requests_len: u64 = Readable::read(reader)?;
+ let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0..pending_claim_requests_len {
+ pending_claim_requests.insert(Readable::read(reader)?, Readable::read(reader)?);
+ }
+
+ let claimable_outpoints_len: u64 = Readable::read(reader)?;
+ let mut claimable_outpoints = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0..claimable_outpoints_len {
+ let outpoint = Readable::read(reader)?;
+ let ancestor_claim_txid = Readable::read(reader)?;
+ let height = Readable::read(reader)?;
+ claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
+ }
+ let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
+ let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0..waiting_threshold_conf_len {
+ let height_target = Readable::read(reader)?;
+ let events_len: u64 = Readable::read(reader)?;
+ let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
+ for _ in 0..events_len {
+ let ev = match <u8 as Readable>::read(reader)? {
+ 0 => {
+ let claim_request = Readable::read(reader)?;
+ OnchainEvent::Claim {
+ claim_request
+ }
+ },
+ 1 => {
+ let outpoint = Readable::read(reader)?;
+ let input_material = Readable::read(reader)?;
+ OnchainEvent::ContentiousOutpoint {
+ outpoint,
+ input_material
+ }
+ }
+ _ => return Err(DecodeError::InvalidValue),
+ };
+ events.push(ev);
+ }
+ onchain_events_waiting_threshold_conf.insert(height_target, events);
+ }
+
+ Ok(OnchainTxHandler {
+ destination_script,
+ claimable_outpoints,
+ pending_claim_requests,
+ onchain_events_waiting_threshold_conf,
+ secp_ctx: Secp256k1::new(),
+ logger,
+ })
+ }
+}
+
+impl OnchainTxHandler {
+ pub(super) fn new(destination_script: Script, logger: Arc<Logger>) -> Self {
+ OnchainTxHandler {
+ destination_script,
+ pending_claim_requests: HashMap::new(),
+ claimable_outpoints: HashMap::new(),
+ onchain_events_waiting_threshold_conf: HashMap::new(),
+
+ secp_ctx: Secp256k1::new(),
+ logger,
+ }
+ }
+
+ pub(super) fn get_witnesses_weight(inputs: &[InputDescriptors]) -> usize {
+ let mut tx_weight = 2; // count segwit flags
+ for inp in inputs {
+ // We use expected weight (and not actual) as signatures and time lock delays may vary
+ tx_weight += match inp {
+ // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+ &InputDescriptors::RevokedOfferedHTLC => {
+ 1 + 1 + 73 + 1 + 33 + 1 + 133
+ },
+ // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+ &InputDescriptors::RevokedReceivedHTLC => {
+ 1 + 1 + 73 + 1 + 33 + 1 + 139
+ },
+ // number_of_witness_elements + sig_length + remotehtlc_sig + preimage_length + preimage + witness_script_length + witness_script
+ &InputDescriptors::OfferedHTLC => {
+ 1 + 1 + 73 + 1 + 32 + 1 + 133
+ },
+ // number_of_witness_elements + sig_length + revocation_sig + pubkey_length + revocationpubkey + witness_script_length + witness_script
+ &InputDescriptors::ReceivedHTLC => {
+ 1 + 1 + 73 + 1 + 1 + 1 + 139
+ },
+ // number_of_witness_elements + sig_length + revocation_sig + true_length + op_true + witness_script_length + witness_script
+ &InputDescriptors::RevokedOutput => {
+ 1 + 1 + 73 + 1 + 1 + 1 + 77
+ },
+ };
+ }
+ tx_weight
+ }
+
+ fn get_height_timer(current_height: u32, timelock_expiration: u32) -> u32 {
+ if timelock_expiration <= current_height + 3 {
+ return current_height + 1
+ } else if timelock_expiration - current_height <= 15 {
+ return current_height + 3
+ }
+ current_height + 15
+ }
+
+ /// 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
+ /// (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.
+ fn generate_claim_tx<F: Deref>(&self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: F) -> Option<(u32, u64, Transaction)>
+ where F::Target: FeeEstimator
+ {
+ 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
+ let mut inputs = Vec::new();
+ for outp in cached_claim_datas.per_input_material.keys() {
+ log_trace!(self, "Outpoint {}:{}", outp.txid, outp.vout);
+ inputs.push(TxIn {
+ previous_output: *outp,
+ script_sig: Script::new(),
+ sequence: 0xfffffffd,
+ witness: Vec::new(),
+ });
+ }
+ let mut bumped_tx = Transaction {
+ version: 2,
+ lock_time: 0,
+ input: inputs,
+ output: vec![TxOut {
+ script_pubkey: self.destination_script.clone(),
+ value: 0
+ }],
+ };
+
+ macro_rules! RBF_bump {
+ ($amount: expr, $old_feerate: expr, $fee_estimator: expr, $predicted_weight: expr) => {
+ {
+ let mut used_feerate;
+ // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee...
+ let new_fee = if $old_feerate < $fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::HighPriority) {
+ let mut value = $amount;
+ if subtract_high_prio_fee!(self, $fee_estimator, value, $predicted_weight, used_feerate) {
+ // Overflow check is done in subtract_high_prio_fee
+ $amount - value
+ } else {
+ log_trace!(self, "Can't new-estimation bump new claiming tx, amount {} is too small", $amount);
+ return None;
+ }
+ // ...else just increase the previous feerate by 25% (because that's a nice number)
+ } else {
+ let fee = $old_feerate * $predicted_weight / 750;
+ if $amount <= fee {
+ log_trace!(self, "Can't 25% bump new claiming tx, amount {} is too small", $amount);
+ return None;
+ }
+ fee
+ };
+
+ let previous_fee = $old_feerate * $predicted_weight / 1000;
+ let min_relay_fee = MIN_RELAY_FEE_SAT_PER_1000_WEIGHT * $predicted_weight / 1000;
+ // BIP 125 Opt-in Full Replace-by-Fee Signaling
+ // * 3. The replacement transaction pays an absolute fee of at least the sum paid by the original transactions.
+ // * 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.
+ let new_fee = if new_fee < previous_fee + min_relay_fee {
+ new_fee + previous_fee + min_relay_fee - new_fee
+ } else {
+ new_fee
+ };
+ Some((new_fee, new_fee * 1000 / $predicted_weight))
+ }
+ }
+ }
+
+ let new_timer = Self::get_height_timer(height, cached_claim_datas.soonest_timelock);
+ let mut inputs_witnesses_weight = 0;
+ let mut amt = 0;
+ for per_outp_material in cached_claim_datas.per_input_material.values() {
+ match per_outp_material {
+ &InputMaterial::Revoked { ref script, ref is_htlc, ref amount, .. } => {
+ inputs_witnesses_weight += Self::get_witnesses_weight(if !is_htlc { &[InputDescriptors::RevokedOutput] } else if HTLCType::scriptlen_to_htlctype(script.len()) == Some(HTLCType::OfferedHTLC) { &[InputDescriptors::RevokedOfferedHTLC] } else if HTLCType::scriptlen_to_htlctype(script.len()) == Some(HTLCType::AcceptedHTLC) { &[InputDescriptors::RevokedReceivedHTLC] } else { unreachable!() });
+ amt += *amount;
+ },
+ &InputMaterial::RemoteHTLC { ref preimage, ref amount, .. } => {
+ inputs_witnesses_weight += Self::get_witnesses_weight(if preimage.is_some() { &[InputDescriptors::OfferedHTLC] } else { &[InputDescriptors::ReceivedHTLC] });
+ amt += *amount;
+ },
+ &InputMaterial::LocalHTLC { .. } => { return None; }
+ }
+ }
+
+ let predicted_weight = bumped_tx.get_weight() + inputs_witnesses_weight;
+ let mut new_feerate;
+ // If old feerate is 0, first iteration of this claim, use normal fee calculation
+ if cached_claim_datas.feerate_previous != 0 {
+ if let Some((new_fee, feerate)) = RBF_bump!(amt, cached_claim_datas.feerate_previous, fee_estimator, predicted_weight as u64) {
+ // If new computed fee is superior at the whole claimable amount burn all in fees
+ if new_fee > amt {
+ bumped_tx.output[0].value = 0;
+ } else {
+ bumped_tx.output[0].value = amt - new_fee;
+ }
+ new_feerate = feerate;
+ } else { return None; }
+ } else {
+ if subtract_high_prio_fee!(self, fee_estimator, amt, predicted_weight, new_feerate) {
+ bumped_tx.output[0].value = amt;
+ } else { return None; }
+ }
+ assert!(new_feerate != 0);
+
+ for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
+ match per_outp_material {
+ &InputMaterial::Revoked { ref script, ref pubkey, ref key, ref is_htlc, ref amount } => {
+ let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
+ let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &script, *amount)[..]);
+ let sig = self.secp_ctx.sign(&sighash, &key);
+ bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+ bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+ if *is_htlc {
+ bumped_tx.input[i].witness.push(pubkey.unwrap().clone().serialize().to_vec());
+ } else {
+ bumped_tx.input[i].witness.push(vec!(1));
+ }
+ bumped_tx.input[i].witness.push(script.clone().into_bytes());
+ 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(script.len()) == Some(HTLCType::OfferedHTLC) { "offered" } else if HTLCType::scriptlen_to_htlctype(script.len()) == Some(HTLCType::AcceptedHTLC) { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
+ },
+ &InputMaterial::RemoteHTLC { ref script, ref key, ref preimage, ref amount, ref locktime } => {
+ 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
+ let sighash_parts = bip143::SighashComponents::new(&bumped_tx);
+ let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &script, *amount)[..]);
+ let sig = self.secp_ctx.sign(&sighash, &key);
+ bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+ bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+ if let &Some(preimage) = preimage {
+ bumped_tx.input[i].witness.push(preimage.clone().0.to_vec());
+ } else {
+ bumped_tx.input[i].witness.push(vec![0]);
+ }
+ bumped_tx.input[i].witness.push(script.clone().into_bytes());
+ 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);
+ },
+ &InputMaterial::LocalHTLC { .. } => {
+ //TODO : Given that Local Commitment Transaction and HTLC-Timeout/HTLC-Success are counter-signed by peer, we can't
+ // RBF them. Need a Lightning specs change and package relay modification :
+ // https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-November/016518.html
+ return None;
+ }
+ }
+ }
+ log_trace!(self, "...with timer {}", new_timer);
+ assert!(predicted_weight >= bumped_tx.get_weight());
+ Some((new_timer, new_feerate, bumped_tx))
+ }
+
+ pub(super) fn block_connected<B: Deref, F: Deref>(&mut self, txn_matched: &[&Transaction], claimable_outpoints: Vec<Vec<(u32, bool, BitcoinOutPoint, InputMaterial)>>, height: u32, broadcaster: B, fee_estimator: F) -> Vec<SpendableOutputDescriptor>
+ where B::Target: BroadcasterInterface,
+ F::Target: FeeEstimator
+ {
+ let mut new_claims = Vec::new();
+ let mut aggregated_claim = HashMap::new();
+ let mut aggregated_soonest = ::std::u32::MAX;
+ let mut spendable_outputs = Vec::new();
+
+ // Try to aggregate outputs if they're 1) belong to same parent tx, 2) their
+ // timelock expiration isn't imminent (<= CLTV_SHARED_CLAIM_BUFFER).
+ for siblings_outpoints in claimable_outpoints {
+ for outp in siblings_outpoints {
+ // Don't claim a outpoint twice that would be bad for privacy and may uselessly lock a CPFP input for a while
+ if let Some(_) = self.claimable_outpoints.get(&outp.2) { log_trace!(self, "Bouncing off outpoint {}:{}, already registered its claiming request", outp.2.txid, outp.2.vout); } else {
+ log_trace!(self, "Test if outpoint can be aggregated with expiration {} against {}", outp.0, height + CLTV_SHARED_CLAIM_BUFFER);
+ if outp.0 <= height + CLTV_SHARED_CLAIM_BUFFER || !outp.1 { // Don't aggregate if outpoint absolute timelock is soon or marked as non-aggregable
+ let mut single_input = HashMap::new();
+ single_input.insert(outp.2, outp.3);
+ new_claims.push((outp.0, single_input));
+ } else {
+ aggregated_claim.insert(outp.2, outp.3);
+ if outp.0 < aggregated_soonest {
+ aggregated_soonest = outp.0;
+ }
+ }
+ }
+ }
+ }
+ new_claims.push((aggregated_soonest, aggregated_claim));
+
+ // Generate claim transactions and track them to bump if necessary at
+ // height timer expiration (i.e in how many blocks we're going to take action).
+ for claim in new_claims {
+ let mut claim_material = ClaimTxBumpMaterial { height_timer: 0, feerate_previous: 0, soonest_timelock: claim.0, per_input_material: claim.1.clone() };
+ if let Some((new_timer, new_feerate, tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
+ claim_material.height_timer = new_timer;
+ claim_material.feerate_previous = new_feerate;
+ let txid = tx.txid();
+ self.pending_claim_requests.insert(txid, claim_material);
+ for k in claim.1.keys() {
+ log_trace!(self, "Registering claiming request for {}:{}", k.txid, k.vout);
+ self.claimable_outpoints.insert(k.clone(), (txid, height));
+ }
+ log_trace!(self, "Broadcast onchain {}", log_tx!(tx));
+ spendable_outputs.push(SpendableOutputDescriptor::StaticOutput {
+ outpoint: BitcoinOutPoint { txid: tx.txid(), vout: 0 },
+ output: tx.output[0].clone(),
+ });
+ broadcaster.broadcast_transaction(&tx);
+ }
+ }
+
+ let mut bump_candidates = HashSet::new();
+ for tx in txn_matched {
+ // Scan all input to verify is one of the outpoint spent is of interest for us
+ let mut claimed_outputs_material = Vec::new();
+ for inp in &tx.input {
+ if let Some(first_claim_txid_height) = self.claimable_outpoints.get(&inp.previous_output) {
+ // If outpoint has claim request pending on it...
+ if let Some(claim_material) = self.pending_claim_requests.get_mut(&first_claim_txid_height.0) {
+ //... we need to verify equality between transaction outpoints and claim request
+ // outpoints to know if transaction is the original claim or a bumped one issued
+ // by us.
+ let mut set_equality = true;
+ if claim_material.per_input_material.len() != tx.input.len() {
+ set_equality = false;
+ } else {
+ for (claim_inp, tx_inp) in claim_material.per_input_material.keys().zip(tx.input.iter()) {
+ if *claim_inp != tx_inp.previous_output {
+ set_equality = false;
+ }
+ }
+ }
+
+ macro_rules! clean_claim_request_after_safety_delay {
+ () => {
+ let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
+ match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
+ hash_map::Entry::Occupied(mut entry) => {
+ if !entry.get().contains(&new_event) {
+ entry.get_mut().push(new_event);
+ }
+ },
+ hash_map::Entry::Vacant(entry) => {
+ entry.insert(vec![new_event]);
+ }
+ }
+ }
+ }
+
+ // If this is our transaction (or our counterparty spent all the outputs
+ // before we could anyway with same inputs order than us), wait for
+ // ANTI_REORG_DELAY and clean the RBF tracking map.
+ if set_equality {
+ clean_claim_request_after_safety_delay!();
+ } else { // If false, generate new claim request with update outpoint set
+ for input in tx.input.iter() {
+ if let Some(input_material) = claim_material.per_input_material.remove(&input.previous_output) {
+ claimed_outputs_material.push((input.previous_output, input_material));
+ }
+ // If there are no outpoints left to claim in this request, drop it entirely after ANTI_REORG_DELAY.
+ if claim_material.per_input_material.is_empty() {
+ clean_claim_request_after_safety_delay!();
+ }
+ }
+ //TODO: recompute soonest_timelock to avoid wasting a bit on fees
+ bump_candidates.insert(first_claim_txid_height.0.clone());
+ }
+ break; //No need to iterate further, either tx is our or their
+ } else {
+ panic!("Inconsistencies between pending_claim_requests map and claimable_outpoints map");
+ }
+ }
+ }
+ for (outpoint, input_material) in claimed_outputs_material.drain(..) {
+ let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
+ match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
+ hash_map::Entry::Occupied(mut entry) => {
+ if !entry.get().contains(&new_event) {
+ entry.get_mut().push(new_event);
+ }
+ },
+ hash_map::Entry::Vacant(entry) => {
+ entry.insert(vec![new_event]);
+ }
+ }
+ }
+ }
+
+ // After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
+ if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
+ for ev in events {
+ match ev {
+ OnchainEvent::Claim { claim_request } => {
+ // We may remove a whole set of claim outpoints here, as these one may have
+ // been aggregated in a single tx and claimed so atomically
+ if let Some(bump_material) = self.pending_claim_requests.remove(&claim_request) {
+ for outpoint in bump_material.per_input_material.keys() {
+ self.claimable_outpoints.remove(&outpoint);
+ }
+ }
+ },
+ OnchainEvent::ContentiousOutpoint { outpoint, .. } => {
+ self.claimable_outpoints.remove(&outpoint);
+ }
+ }
+ }
+ }
+
+ // Check if any pending claim request must be rescheduled
+ for (first_claim_txid, ref claim_data) in self.pending_claim_requests.iter() {
+ if claim_data.height_timer == height {
+ bump_candidates.insert(*first_claim_txid);
+ }
+ }
+
+ // Build, bump and rebroadcast tx accordingly
+ for first_claim_txid in bump_candidates.iter() {
+ if let Some((new_timer, new_feerate)) = {
+ if let Some(claim_material) = self.pending_claim_requests.get(first_claim_txid) {
+ if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
+ log_trace!(self, "Broadcast onchain {}", log_tx!(bump_tx));
+ broadcaster.broadcast_transaction(&bump_tx);
+ Some((new_timer, new_feerate))
+ } else { None }
+ } else { unreachable!(); }
+ } {
+ if let Some(claim_material) = self.pending_claim_requests.get_mut(first_claim_txid) {
+ claim_material.height_timer = new_timer;
+ claim_material.feerate_previous = new_feerate;
+ } else { unreachable!(); }
+ }
+ }
+
+ spendable_outputs
+ }
+
+ pub(super) fn block_disconnected<B: Deref, F: Deref>(&mut self, height: u32, broadcaster: B, fee_estimator: F)
+ where B::Target: BroadcasterInterface,
+ F::Target: FeeEstimator
+ {
+ let mut bump_candidates = HashMap::new();
+ if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
+ //- our claim tx on a commitment tx output
+ //- resurect outpoint back in its claimable set and regenerate tx
+ for ev in events {
+ match ev {
+ OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
+ if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
+ if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
+ claim_material.per_input_material.insert(outpoint, input_material);
+ // Using a HashMap guarantee us than if we have multiple outpoints getting
+ // resurrected only one bump claim tx is going to be broadcast
+ bump_candidates.insert(ancestor_claimable_txid.clone(), claim_material.clone());
+ }
+ }
+ },
+ _ => {},
+ }
+ }
+ }
+ for (_, claim_material) in bump_candidates.iter_mut() {
+ if let Some((new_timer, new_feerate, bump_tx)) = self.generate_claim_tx(height, &claim_material, &*fee_estimator) {
+ claim_material.height_timer = new_timer;
+ claim_material.feerate_previous = new_feerate;
+ broadcaster.broadcast_transaction(&bump_tx);
+ }
+ }
+ for (ancestor_claim_txid, claim_material) in bump_candidates.drain() {
+ self.pending_claim_requests.insert(ancestor_claim_txid.0, claim_material);
+ }
+ //TODO: if we implement cross-block aggregated claim transaction we need to refresh set of outpoints and regenerate tx but
+ // right now if one of the outpoint get disconnected, just erase whole pending claim request.
+ let mut remove_request = Vec::new();
+ self.claimable_outpoints.retain(|_, ref v|
+ if v.1 == height {
+ remove_request.push(v.0.clone());
+ false
+ } else { true });
+ for req in remove_request {
+ self.pending_claim_requests.remove(&req);
+ }
+ }
+}
projects / rust-lightning / blobdiff