//! [`Event`]: crate::events::Event
use alloc::collections::BTreeMap;
-use core::convert::TryInto;
use core::ops::Deref;
-use crate::chain::chaininterface::BroadcasterInterface;
+use crate::chain::chaininterface::{BroadcasterInterface, compute_feerate_sat_per_1000_weight, fee_for_weight, FEERATE_FLOOR_SATS_PER_KW};
use crate::chain::ClaimId;
use crate::io_extras::sink;
use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
use crate::ln::features::ChannelTypeFeatures;
use crate::ln::PaymentPreimage;
use crate::prelude::*;
-use crate::sign::{ChannelSigner, EcdsaChannelSigner, SignerProvider};
+use crate::sign::{EcdsaChannelSigner, SignerProvider, WriteableEcdsaChannelSigner};
use crate::sync::Mutex;
use crate::util::logger::Logger;
const BASE_INPUT_WEIGHT: u64 = BASE_INPUT_SIZE * WITNESS_SCALE_FACTOR as u64;
-// TODO: Define typed abstraction over feerates to handle their conversions.
-fn compute_feerate_sat_per_1000_weight(fee_sat: u64, weight: u64) -> u32 {
- (fee_sat * 1000 / weight).try_into().unwrap_or(u32::max_value())
-}
-const fn fee_for_weight(feerate_sat_per_1000_weight: u32, weight: u64) -> u64 {
- ((feerate_sat_per_1000_weight as u64 * weight) + 1000 - 1) / 1000
-}
-
/// The parameters required to derive a channel signer via [`SignerProvider`].
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ChannelDerivationParameters {
}
/// Derives the channel signer required to sign the anchor input.
- pub fn derive_channel_signer<SP: Deref>(&self, signer_provider: &SP) -> <SP::Target as SignerProvider>::Signer
+ pub fn derive_channel_signer<S: WriteableEcdsaChannelSigner, SP: Deref>(&self, signer_provider: &SP) -> S
where
- SP::Target: SignerProvider
+ SP::Target: SignerProvider<Signer = S>
{
let mut signer = signer_provider.derive_channel_signer(
self.channel_derivation_parameters.value_satoshis,
}
impl HTLCDescriptor {
+ /// Returns the outpoint of the HTLC output in the commitment transaction. This is the outpoint
+ /// being spent by the HTLC input in the HTLC transaction.
+ pub fn outpoint(&self) -> OutPoint {
+ OutPoint {
+ txid: self.commitment_txid,
+ vout: self.htlc.transaction_output_index.unwrap(),
+ }
+ }
+
/// Returns the UTXO to be spent by the HTLC input, which can be obtained via
/// [`Self::unsigned_tx_input`].
pub fn previous_utxo<C: secp256k1::Signing + secp256k1::Verification>(&self, secp: &Secp256k1<C>) -> TxOut {
}
/// Derives the channel signer required to sign the HTLC input.
- pub fn derive_channel_signer<SP: Deref>(&self, signer_provider: &SP) -> <SP::Target as SignerProvider>::Signer
+ pub fn derive_channel_signer<S: WriteableEcdsaChannelSigner, SP: Deref>(&self, signer_provider: &SP) -> S
where
- SP::Target: SignerProvider
+ SP::Target: SignerProvider<Signer = S>
{
let mut signer = signer_provider.derive_channel_signer(
self.channel_derivation_parameters.value_satoshis,
/// An input that must be included in a transaction when performing coin selection through
/// [`CoinSelectionSource::select_confirmed_utxos`]. It is guaranteed to be a SegWit input, so it
/// must have an empty [`TxIn::script_sig`] when spent.
+#[derive(Clone, Debug, Hash, PartialOrd, Ord, PartialEq, Eq)]
pub struct Input {
/// The unique identifier of the input.
pub outpoint: OutPoint,
/// An unspent transaction output that is available to spend resulting from a successful
/// [`CoinSelection`] attempt.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Hash, PartialOrd, Ord, PartialEq, Eq)]
pub struct Utxo {
/// The unique identifier of the output.
pub outpoint: OutPoint,
/// The result of a successful coin selection attempt for a transaction requiring additional UTXOs
/// to cover its fees.
+#[derive(Clone, Debug)]
pub struct CoinSelection {
/// The set of UTXOs (with at least 1 confirmation) to spend and use within a transaction
/// requiring additional fees.
/// which UTXOs to double spend is left to the implementation, but it must strive to keep the
/// set of other claims being double spent to a minimum.
fn select_confirmed_utxos(
- &self, claim_id: ClaimId, must_spend: &[Input], must_pay_to: &[TxOut],
+ &self, claim_id: ClaimId, must_spend: Vec<Input>, must_pay_to: &[TxOut],
target_feerate_sat_per_1000_weight: u32,
) -> Result<CoinSelection, ()>;
/// Signs and provides the full witness for all inputs within the transaction known to the
/// trait (i.e., any provided via [`CoinSelectionSource::select_confirmed_utxos`]).
- fn sign_tx(&self, tx: &mut Transaction) -> Result<(), ()>;
+ fn sign_tx(&self, tx: Transaction) -> Result<Transaction, ()>;
}
/// An alternative to [`CoinSelectionSource`] that can be implemented and used along [`Wallet`] to
/// Signs and provides the full [`TxIn::script_sig`] and [`TxIn::witness`] for all inputs within
/// the transaction known to the wallet (i.e., any provided via
/// [`WalletSource::list_confirmed_utxos`]).
- fn sign_tx(&self, tx: &mut Transaction) -> Result<(), ()>;
+ fn sign_tx(&self, tx: Transaction) -> Result<Transaction, ()>;
}
/// A wrapper over [`WalletSource`] that implements [`CoinSelection`] by preferring UTXOs that would
/// avoid conflicting double spends. If not enough UTXOs are available to do so, conflicting double
/// spends may happen.
-pub struct Wallet<W: Deref> where W::Target: WalletSource {
+pub struct Wallet<W: Deref, L: Deref>
+where
+ W::Target: WalletSource,
+ L::Target: Logger
+{
source: W,
+ logger: L,
// TODO: Do we care about cleaning this up once the UTXOs have a confirmed spend? We can do so
// by checking whether any UTXOs that exist in the map are no longer returned in
// `list_confirmed_utxos`.
locked_utxos: Mutex<HashMap<OutPoint, ClaimId>>,
}
-impl<W: Deref> Wallet<W> where W::Target: WalletSource {
+impl<W: Deref, L: Deref> Wallet<W, L>
+where
+ W::Target: WalletSource,
+ L::Target: Logger
+{
/// Returns a new instance backed by the given [`WalletSource`] that serves as an implementation
/// of [`CoinSelectionSource`].
- pub fn new(source: W) -> Self {
- Self { source, locked_utxos: Mutex::new(HashMap::new()) }
+ pub fn new(source: W, logger: L) -> Self {
+ Self { source, logger, locked_utxos: Mutex::new(HashMap::new()) }
}
/// Performs coin selection on the set of UTXOs obtained from
let mut eligible_utxos = utxos.iter().filter_map(|utxo| {
if let Some(utxo_claim_id) = locked_utxos.get(&utxo.outpoint) {
if *utxo_claim_id != claim_id && !force_conflicting_utxo_spend {
+ log_trace!(self.logger, "Skipping UTXO {} to prevent conflicting spend", utxo.outpoint);
return None;
}
}
if should_spend {
Some((utxo, fee_to_spend_utxo))
} else {
+ log_trace!(self.logger, "Skipping UTXO {} due to dust proximity after spend", utxo.outpoint);
None
}
}).collect::<Vec<_>>();
selected_utxos.push(utxo.clone());
}
if selected_amount < target_amount_sat + total_fees {
+ log_debug!(self.logger, "Insufficient funds to meet target feerate {} sat/kW",
+ target_feerate_sat_per_1000_weight);
return Err(());
}
for utxo in &selected_utxos {
);
let change_output_amount = remaining_amount.saturating_sub(change_output_fee);
let change_output = if change_output_amount < change_script.dust_value().to_sat() {
+ log_debug!(self.logger, "Coin selection attempt did not yield change output");
None
} else {
Some(TxOut { script_pubkey: change_script, value: change_output_amount })
}
}
-impl<W: Deref> CoinSelectionSource for Wallet<W> where W::Target: WalletSource {
+impl<W: Deref, L: Deref> CoinSelectionSource for Wallet<W, L>
+where
+ W::Target: WalletSource,
+ L::Target: Logger
+{
fn select_confirmed_utxos(
- &self, claim_id: ClaimId, must_spend: &[Input], must_pay_to: &[TxOut],
+ &self, claim_id: ClaimId, must_spend: Vec<Input>, must_pay_to: &[TxOut],
target_feerate_sat_per_1000_weight: u32,
) -> Result<CoinSelection, ()> {
let utxos = self.source.list_confirmed_utxos()?;
((BASE_TX_SIZE + total_output_size) * WITNESS_SCALE_FACTOR as u64);
let target_amount_sat = must_pay_to.iter().map(|output| output.value).sum();
let do_coin_selection = |force_conflicting_utxo_spend: bool, tolerate_high_network_feerates: bool| {
+ log_debug!(self.logger, "Attempting coin selection targeting {} sat/kW (force_conflicting_utxo_spend = {}, tolerate_high_network_feerates = {})",
+ target_feerate_sat_per_1000_weight, force_conflicting_utxo_spend, tolerate_high_network_feerates);
self.select_confirmed_utxos_internal(
&utxos, claim_id, force_conflicting_utxo_spend, tolerate_high_network_feerates,
target_feerate_sat_per_1000_weight, preexisting_tx_weight, target_amount_sat,
.or_else(|_| do_coin_selection(true, true))
}
- fn sign_tx(&self, tx: &mut Transaction) -> Result<(), ()> {
+ fn sign_tx(&self, tx: Transaction) -> Result<Transaction, ()> {
self.source.sign_tx(tx)
}
}
// match, but we still need to have at least one output in the transaction for it to be
// considered standard. We choose to go with an empty OP_RETURN as it is the cheapest
// way to include a dummy output.
+ log_debug!(self.logger, "Including dummy OP_RETURN output since an output is needed and a change output was not provided");
tx.output.push(TxOut {
value: 0,
script_pubkey: Script::new_op_return(&[]),
}
}
- /// Returns an unsigned transaction spending an anchor output of the commitment transaction, and
- /// any additional UTXOs sourced, to bump the commitment transaction's fee.
- fn build_anchor_tx(
- &self, claim_id: ClaimId, target_feerate_sat_per_1000_weight: u32,
- commitment_tx: &Transaction, anchor_descriptor: &AnchorDescriptor,
- ) -> Result<Transaction, ()> {
+ /// Handles a [`BumpTransactionEvent::ChannelClose`] event variant by producing a fully-signed
+ /// transaction spending an anchor output of the commitment transaction to bump its fee and
+ /// broadcasts them to the network as a package.
+ fn handle_channel_close(
+ &self, claim_id: ClaimId, package_target_feerate_sat_per_1000_weight: u32,
+ commitment_tx: &Transaction, commitment_tx_fee_sat: u64, anchor_descriptor: &AnchorDescriptor,
+ ) -> Result<(), ()> {
+ // Our commitment transaction already has fees allocated to it, so we should take them into
+ // account. We compute its feerate and subtract it from the package target, using the result
+ // as the target feerate for our anchor transaction. Unfortunately, this results in users
+ // overpaying by a small margin since we don't yet know the anchor transaction size, and
+ // avoiding the small overpayment only makes our API even more complex.
+ let commitment_tx_sat_per_1000_weight: u32 = compute_feerate_sat_per_1000_weight(
+ commitment_tx_fee_sat, commitment_tx.weight() as u64,
+ );
+ let anchor_target_feerate_sat_per_1000_weight = core::cmp::max(
+ package_target_feerate_sat_per_1000_weight - commitment_tx_sat_per_1000_weight,
+ FEERATE_FLOOR_SATS_PER_KW,
+ );
+
+ log_debug!(self.logger, "Peforming coin selection for anchor transaction targeting {} sat/kW",
+ anchor_target_feerate_sat_per_1000_weight);
let must_spend = vec![Input {
outpoint: anchor_descriptor.outpoint,
previous_utxo: anchor_descriptor.previous_utxo(),
satisfaction_weight: commitment_tx.weight() as u64 + ANCHOR_INPUT_WITNESS_WEIGHT + EMPTY_SCRIPT_SIG_WEIGHT,
}];
let coin_selection = self.utxo_source.select_confirmed_utxos(
- claim_id, &must_spend, &[], target_feerate_sat_per_1000_weight,
+ claim_id, must_spend, &[], anchor_target_feerate_sat_per_1000_weight,
)?;
- let mut tx = Transaction {
+ let mut anchor_tx = Transaction {
version: 2,
lock_time: PackedLockTime::ZERO, // TODO: Use next best height.
input: vec![anchor_descriptor.unsigned_tx_input()],
output: vec![],
};
- self.process_coin_selection(&mut tx, coin_selection);
- Ok(tx)
- }
+ #[cfg(debug_assertions)]
+ let total_satisfaction_weight =
+ coin_selection.confirmed_utxos.iter().map(|utxo| utxo.satisfaction_weight).sum::<u64>() +
+ ANCHOR_INPUT_WITNESS_WEIGHT + EMPTY_SCRIPT_SIG_WEIGHT;
- /// Handles a [`BumpTransactionEvent::ChannelClose`] event variant by producing a fully-signed
- /// transaction spending an anchor output of the commitment transaction to bump its fee and
- /// broadcasts them to the network as a package.
- fn handle_channel_close(
- &self, claim_id: ClaimId, package_target_feerate_sat_per_1000_weight: u32,
- commitment_tx: &Transaction, commitment_tx_fee_sat: u64, anchor_descriptor: &AnchorDescriptor,
- ) -> Result<(), ()> {
- // Compute the feerate the anchor transaction must meet to meet the overall feerate for the
- // package (commitment + anchor transactions).
- let commitment_tx_sat_per_1000_weight: u32 = compute_feerate_sat_per_1000_weight(
- commitment_tx_fee_sat, commitment_tx.weight() as u64,
- );
- if commitment_tx_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight {
- // If the commitment transaction already has a feerate high enough on its own, broadcast
- // it as is without a child.
- self.broadcaster.broadcast_transactions(&[&commitment_tx]);
- return Ok(());
- }
+ self.process_coin_selection(&mut anchor_tx, coin_selection);
+ let anchor_txid = anchor_tx.txid();
- let mut anchor_tx = self.build_anchor_tx(
- claim_id, package_target_feerate_sat_per_1000_weight, commitment_tx, anchor_descriptor,
- )?;
debug_assert_eq!(anchor_tx.output.len(), 1);
+ #[cfg(debug_assertions)]
+ let unsigned_tx_weight = anchor_tx.weight() as u64 - (anchor_tx.input.len() as u64 * EMPTY_SCRIPT_SIG_WEIGHT);
+
+ log_debug!(self.logger, "Signing anchor transaction {}", anchor_txid);
+ anchor_tx = self.utxo_source.sign_tx(anchor_tx)?;
- self.utxo_source.sign_tx(&mut anchor_tx)?;
let signer = anchor_descriptor.derive_channel_signer(&self.signer_provider);
let anchor_sig = signer.sign_holder_anchor_input(&anchor_tx, 0, &self.secp)?;
anchor_tx.input[0].witness = anchor_descriptor.tx_input_witness(&anchor_sig);
+ #[cfg(debug_assertions)] {
+ let signed_tx_weight = anchor_tx.weight() as u64;
+ let expected_signed_tx_weight = unsigned_tx_weight + total_satisfaction_weight;
+ // Our estimate should be within a 1% error margin of the actual weight and we should
+ // never underestimate.
+ assert!(expected_signed_tx_weight >= signed_tx_weight &&
+ expected_signed_tx_weight - (expected_signed_tx_weight / 100) <= signed_tx_weight);
+ }
+
+ log_info!(self.logger, "Broadcasting anchor transaction {} to bump channel close with txid {}",
+ anchor_txid, commitment_tx.txid());
self.broadcaster.broadcast_transactions(&[&commitment_tx, &anchor_tx]);
Ok(())
}
- /// Returns an unsigned, fee-bumped HTLC transaction, along with the set of signers required to
- /// fulfill the witness for each HTLC input within it.
- fn build_htlc_tx(
+ /// Handles a [`BumpTransactionEvent::HTLCResolution`] event variant by producing a
+ /// fully-signed, fee-bumped HTLC transaction that is broadcast to the network.
+ fn handle_htlc_resolution(
&self, claim_id: ClaimId, target_feerate_sat_per_1000_weight: u32,
htlc_descriptors: &[HTLCDescriptor], tx_lock_time: PackedLockTime,
- ) -> Result<Transaction, ()> {
- let mut tx = Transaction {
+ ) -> Result<(), ()> {
+ let mut htlc_tx = Transaction {
version: 2,
lock_time: tx_lock_time,
input: vec![],
HTLC_TIMEOUT_INPUT_ANCHOR_WITNESS_WEIGHT
},
});
- tx.input.push(htlc_input);
+ htlc_tx.input.push(htlc_input);
let htlc_output = htlc_descriptor.tx_output(&self.secp);
- tx.output.push(htlc_output);
+ htlc_tx.output.push(htlc_output);
}
+ log_debug!(self.logger, "Peforming coin selection for HTLC transaction targeting {} sat/kW",
+ target_feerate_sat_per_1000_weight);
+ #[cfg(debug_assertions)]
+ let must_spend_satisfaction_weight =
+ must_spend.iter().map(|input| input.satisfaction_weight).sum::<u64>();
let coin_selection = self.utxo_source.select_confirmed_utxos(
- claim_id, &must_spend, &tx.output, target_feerate_sat_per_1000_weight,
+ claim_id, must_spend, &htlc_tx.output, target_feerate_sat_per_1000_weight,
)?;
- self.process_coin_selection(&mut tx, coin_selection);
- Ok(tx)
- }
+ #[cfg(debug_assertions)]
+ let total_satisfaction_weight =
+ coin_selection.confirmed_utxos.iter().map(|utxo| utxo.satisfaction_weight).sum::<u64>() +
+ must_spend_satisfaction_weight;
+ self.process_coin_selection(&mut htlc_tx, coin_selection);
- /// Handles a [`BumpTransactionEvent::HTLCResolution`] event variant by producing a
- /// fully-signed, fee-bumped HTLC transaction that is broadcast to the network.
- fn handle_htlc_resolution(
- &self, claim_id: ClaimId, target_feerate_sat_per_1000_weight: u32,
- htlc_descriptors: &[HTLCDescriptor], tx_lock_time: PackedLockTime,
- ) -> Result<(), ()> {
- let mut htlc_tx = self.build_htlc_tx(
- claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time,
- )?;
+ #[cfg(debug_assertions)]
+ let unsigned_tx_weight = htlc_tx.weight() as u64 - (htlc_tx.input.len() as u64 * EMPTY_SCRIPT_SIG_WEIGHT);
+
+ log_debug!(self.logger, "Signing HTLC transaction {}", htlc_tx.txid());
+ htlc_tx = self.utxo_source.sign_tx(htlc_tx)?;
- self.utxo_source.sign_tx(&mut htlc_tx)?;
let mut signers = BTreeMap::new();
for (idx, htlc_descriptor) in htlc_descriptors.iter().enumerate() {
let signer = signers.entry(htlc_descriptor.channel_derivation_parameters.keys_id)
htlc_tx.input[idx].witness = htlc_descriptor.tx_input_witness(&htlc_sig, &witness_script);
}
+ #[cfg(debug_assertions)] {
+ let signed_tx_weight = htlc_tx.weight() as u64;
+ let expected_signed_tx_weight = unsigned_tx_weight + total_satisfaction_weight;
+ // Our estimate should be within a 1% error margin of the actual weight and we should
+ // never underestimate.
+ assert!(expected_signed_tx_weight >= signed_tx_weight &&
+ expected_signed_tx_weight - (expected_signed_tx_weight / 100) <= signed_tx_weight);
+ }
+
+ log_info!(self.logger, "Broadcasting {}", log_tx!(htlc_tx));
self.broadcaster.broadcast_transactions(&[&htlc_tx]);
Ok(())
}
match event {
BumpTransactionEvent::ChannelClose {
claim_id, package_target_feerate_sat_per_1000_weight, commitment_tx,
- anchor_descriptor, commitment_tx_fee_satoshis, ..
+ commitment_tx_fee_satoshis, anchor_descriptor, ..
} => {
+ log_info!(self.logger, "Handling channel close bump (claim_id = {}, commitment_txid = {})",
+ log_bytes!(claim_id.0), commitment_tx.txid());
if let Err(_) = self.handle_channel_close(
*claim_id, *package_target_feerate_sat_per_1000_weight, commitment_tx,
*commitment_tx_fee_satoshis, anchor_descriptor,
BumpTransactionEvent::HTLCResolution {
claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time,
} => {
+ log_info!(self.logger, "Handling HTLC bump (claim_id = {}, htlcs_to_claim = {})",
+ log_bytes!(claim_id.0), log_iter!(htlc_descriptors.iter().map(|d| d.outpoint())));
if let Err(_) = self.handle_htlc_resolution(
*claim_id, *target_feerate_sat_per_1000_weight, htlc_descriptors, *tx_lock_time,
) {
projects / rust-lightning / blobdiff