//! Includes traits for monitoring and receiving notifications of new blocks and block
//! disconnections, transaction broadcasting, and feerate information requests.
-use bitcoin::blockdata::block::BlockHeader;
-use bitcoin::blockdata::transaction::Transaction;
-use bitcoin::blockdata::script::Script;
-use bitcoin::hash_types::Txid;
+use core::{cmp, ops::Deref};
+use core::convert::TryInto;
-use std::collections::HashSet;
+use bitcoin::blockdata::transaction::Transaction;
-/// An interface to send a transaction to the Bitcoin network.
-pub trait BroadcasterInterface: Sync + Send {
- /// Sends a transaction out to (hopefully) be mined.
- fn broadcast_transaction(&self, tx: &Transaction);
+// TODO: Define typed abstraction over feerates to handle their conversions.
+pub(crate) fn compute_feerate_sat_per_1000_weight(fee_sat: u64, weight: u64) -> u32 {
+ (fee_sat * 1000 / weight).try_into().unwrap_or(u32::max_value())
+}
+pub(crate) 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
}
-/// A trait indicating a desire to listen for events from the chain
-pub trait ChainListener: Sync + Send {
- /// Notifies a listener that a block was connected. Transactions may be filtered and are given
- /// paired with their position within the block.
- fn block_connected(&self, header: &BlockHeader, txdata: &[(usize, &Transaction)], height: u32);
-
- /// Notifies a listener that a block was disconnected.
- /// Unlike block_connected, this *must* never be called twice for the same disconnect event.
- /// Height must be the one of the block which was disconnected (not new height of the best chain)
- fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32);
+/// An interface to send a transaction to the Bitcoin network.
+pub trait BroadcasterInterface {
+ /// Sends a list of transactions out to (hopefully) be mined.
+ /// This only needs to handle the actual broadcasting of transactions, LDK will automatically
+ /// rebroadcast transactions that haven't made it into a block.
+ ///
+ /// In some cases LDK may attempt to broadcast a transaction which double-spends another
+ /// and this isn't a bug and can be safely ignored.
+ ///
+ /// If more than one transaction is given, these transactions should be considered to be a
+ /// package and broadcast together. Some of the transactions may or may not depend on each other,
+ /// be sure to manage both cases correctly.
+ ///
+ /// Bitcoin transaction packages are defined in BIP 331 and here:
+ /// https://github.com/bitcoin/bitcoin/blob/master/doc/policy/packages.md
+ fn broadcast_transactions(&self, txs: &[&Transaction]);
}
-/// An enum that represents the speed at which we want a transaction to confirm used for feerate
+/// An enum that represents the priority at which we want a transaction to confirm used for feerate
/// estimation.
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
pub enum ConfirmationTarget {
- /// We are happy with this transaction confirming slowly when feerate drops some.
+ /// We'd like a transaction to confirm in the future, but don't want to commit most of the fees
+ /// required to do so yet. The remaining fees will come via a Child-Pays-For-Parent (CPFP) fee
+ /// bump of the transaction.
+ ///
+ /// The feerate returned should be the absolute minimum feerate required to enter most node
+ /// mempools across the network. Note that if you are not able to obtain this feerate estimate,
+ /// you should likely use the furthest-out estimate allowed by your fee estimator.
+ MempoolMinimum,
+ /// We are happy with a transaction confirming slowly, at least within a day or so worth of
+ /// blocks.
Background,
- /// We'd like this transaction to confirm without major delay, but 12-18 blocks is fine.
+ /// We'd like a transaction to confirm without major delayed, i.e., within the next 12-24 blocks.
Normal,
- /// We'd like this transaction to confirm in the next few blocks.
+ /// We'd like a transaction to confirm in the next few blocks.
HighPriority,
}
/// A trait which should be implemented to provide feerate information on a number of time
/// horizons.
///
+/// If access to a local mempool is not feasible, feerate estimates should be fetched from a set of
+/// third-parties hosting them. Note that this enables them to affect the propagation of your
+/// pre-signed transactions at any time and therefore endangers the safety of channels funds. It
+/// should be considered carefully as a deployment.
+///
/// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
-/// called from inside the library in response to ChainListener events, P2P events, or timer
-/// events).
-pub trait FeeEstimator: Sync + Send {
+/// called from inside the library in response to chain events, P2P events, or timer events).
+pub trait FeeEstimator {
/// Gets estimated satoshis of fee required per 1000 Weight-Units.
///
- /// Must be no smaller than 253 (ie 1 satoshi-per-byte rounded up to ensure later round-downs
- /// don't put us below 1 satoshi-per-byte).
+ /// LDK will wrap this method and ensure that the value returned is no smaller than 253
+ /// (ie 1 satoshi-per-byte rounded up to ensure later round-downs don't put us below 1 satoshi-per-byte).
///
- /// This translates to:
+ /// The following unit conversions can be used to convert to sats/KW:
/// * satoshis-per-byte * 250
- /// * ceil(satoshis-per-kbyte / 4)
+ /// * satoshis-per-kbyte / 4
fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
}
/// Minimum relay fee as required by bitcoin network mempool policy.
pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;
+/// Minimum feerate that takes a sane approach to bitcoind weight-to-vbytes rounding.
+/// See the following Core Lightning commit for an explanation:
+/// <https://github.com/ElementsProject/lightning/commit/2e687b9b352c9092b5e8bd4a688916ac50b44af0>
+pub const FEERATE_FLOOR_SATS_PER_KW: u32 = 253;
-/// Utility for tracking registered txn/outpoints and checking for matches
-#[cfg_attr(test, derive(PartialEq))]
-pub struct ChainWatchedUtil {
- watch_all: bool,
-
- // We are more conservative in matching during testing to ensure everything matches *exactly*,
- // even though during normal runtime we take more optimized match approaches...
- #[cfg(test)]
- watched_txn: HashSet<(Txid, Script)>,
- #[cfg(not(test))]
- watched_txn: HashSet<Script>,
+/// Wraps a `Deref` to a `FeeEstimator` so that any fee estimations provided by it
+/// are bounded below by `FEERATE_FLOOR_SATS_PER_KW` (253 sats/KW).
+///
+/// Note that this does *not* implement [`FeeEstimator`] to make it harder to accidentally mix the
+/// two.
+pub(crate) struct LowerBoundedFeeEstimator<F: Deref>(pub F) where F::Target: FeeEstimator;
+
+impl<F: Deref> LowerBoundedFeeEstimator<F> where F::Target: FeeEstimator {
+ /// Creates a new `LowerBoundedFeeEstimator` which wraps the provided fee_estimator
+ pub fn new(fee_estimator: F) -> Self {
+ LowerBoundedFeeEstimator(fee_estimator)
+ }
- watched_outpoints: HashSet<(Txid, u32)>,
+ pub fn bounded_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ cmp::max(
+ self.0.get_est_sat_per_1000_weight(confirmation_target),
+ FEERATE_FLOOR_SATS_PER_KW,
+ )
+ }
}
-impl ChainWatchedUtil {
- /// Constructs an empty (watches nothing) ChainWatchedUtil
- pub fn new() -> Self {
- Self {
- watch_all: false,
- watched_txn: HashSet::new(),
- watched_outpoints: HashSet::new(),
- }
+#[cfg(test)]
+mod tests {
+ use super::{FEERATE_FLOOR_SATS_PER_KW, LowerBoundedFeeEstimator, ConfirmationTarget, FeeEstimator};
+
+ struct TestFeeEstimator {
+ sat_per_kw: u32,
}
- /// Registers a tx for monitoring, returning true if it was a new tx and false if we'd already
- /// been watching for it.
- pub fn register_tx(&mut self, txid: &Txid, script_pub_key: &Script) -> bool {
- if self.watch_all { return false; }
- #[cfg(test)]
- {
- self.watched_txn.insert((txid.clone(), script_pub_key.clone()))
- }
- #[cfg(not(test))]
- {
- let _tx_unused = txid; // It's used in cfg(test), though
- self.watched_txn.insert(script_pub_key.clone())
+ impl FeeEstimator for TestFeeEstimator {
+ fn get_est_sat_per_1000_weight(&self, _: ConfirmationTarget) -> u32 {
+ self.sat_per_kw
}
}
- /// Registers an outpoint for monitoring, returning true if it was a new outpoint and false if
- /// we'd already been watching for it
- pub fn register_outpoint(&mut self, outpoint: (Txid, u32), _script_pub_key: &Script) -> bool {
- if self.watch_all { return false; }
- self.watched_outpoints.insert(outpoint)
- }
+ #[test]
+ fn test_fee_estimator_less_than_floor() {
+ let sat_per_kw = FEERATE_FLOOR_SATS_PER_KW - 1;
+ let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
+ let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
- /// Sets us to match all transactions, returning true if this is a new setting and false if
- /// we'd already been set to match everything.
- pub fn watch_all(&mut self) -> bool {
- if self.watch_all { return false; }
- self.watch_all = true;
- true
+ assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), FEERATE_FLOOR_SATS_PER_KW);
}
- /// Checks if a given transaction matches the current filter.
- pub fn does_match_tx(&self, tx: &Transaction) -> bool {
- if self.watch_all {
- return true;
- }
- for out in tx.output.iter() {
- #[cfg(test)]
- for &(ref txid, ref script) in self.watched_txn.iter() {
- if *script == out.script_pubkey {
- if tx.txid() == *txid {
- return true;
- }
- }
- }
- #[cfg(not(test))]
- for script in self.watched_txn.iter() {
- if *script == out.script_pubkey {
- return true;
- }
- }
- }
- for input in tx.input.iter() {
- for outpoint in self.watched_outpoints.iter() {
- let &(outpoint_hash, outpoint_index) = outpoint;
- if outpoint_hash == input.previous_output.txid && outpoint_index == input.previous_output.vout {
- return true;
- }
- }
- }
- false
+ #[test]
+ fn test_fee_estimator_greater_than_floor() {
+ let sat_per_kw = FEERATE_FLOOR_SATS_PER_KW + 1;
+ let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
+ let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
+
+ assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), sat_per_kw);
}
}
projects / rust-lightning / blobdiff