X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fchaininterface.rs;h=913fa007d378e91ba5666e3d34ae11c15010ce13;hb=620244dc2ec3153a61e009b80a8c59cf41514482;hp=50570dfdf119af0faab180e2d6e32efc266da240;hpb=a491200f96760315fa420e433d0e60c4e6503a97;p=rust-lightning diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs index 50570dfd..913fa007 100644 --- a/lightning/src/chain/chaininterface.rs +++ b/lightning/src/chain/chaininterface.rs @@ -14,30 +14,65 @@ //! 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 { @@ -56,7 +91,7 @@ pub trait FeeEstimator { 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; /// Wraps a `Deref` to a `FeeEstimator` so that any fee estimations provided by it @@ -72,7 +107,7 @@ impl LowerBoundedFeeEstimator where F::Target: FeeEstimator { LowerBoundedFeeEstimator(fee_estimator) } - pub 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, @@ -100,7 +135,7 @@ mod tests { 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] @@ -109,6 +144,6 @@ mod tests { 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); } }