//! disconnections, transaction broadcasting, and feerate information requests.
use core::{cmp, ops::Deref};
+use core::convert::TryInto;
use bitcoin::blockdata::transaction::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
+}
+
/// An interface to send a transaction to the Bitcoin network.
pub trait BroadcasterInterface {
- /// Sends a transaction out to (hopefully) be mined.
- fn broadcast_transaction(&self, tx: &Transaction);
+ /// 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, PartialEq, Eq)]
+#[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 chain events, P2P events, or timer events).
pub trait FeeEstimator {
fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
}
-// We need `FeeEstimator` implemented so that in some places where we only have a shared
-// reference to a `Deref` to a `FeeEstimator`, we can still wrap it.
-impl<D: Deref> FeeEstimator for D where D::Target: FeeEstimator {
- fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
- (**self).get_est_sat_per_1000_weight(confirmation_target)
- }
-}
-
/// 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.
pub const FEERATE_FLOOR_SATS_PER_KW: u32 = 253;
/// 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)
+/// 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 {
pub fn new(fee_estimator: F) -> Self {
LowerBoundedFeeEstimator(fee_estimator)
}
-}
-impl<F: Deref> FeeEstimator for LowerBoundedFeeEstimator<F> where F::Target: FeeEstimator {
- fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> 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,
let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
- assert_eq!(fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background), FEERATE_FLOOR_SATS_PER_KW);
+ assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), FEERATE_FLOOR_SATS_PER_KW);
}
#[test]
let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
- assert_eq!(fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background), sat_per_kw);
+ assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), sat_per_kw);
}
}
projects / rust-lightning / blobdiff