rgb_lightning/chain/
chaininterface.rs

1// This file is Copyright its original authors, visible in version control
2// history.
3//
4// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7// You may not use this file except in accordance with one or both of these
8// licenses.
9
10//! Traits and utility impls which allow other parts of rust-lightning to interact with the
11//! blockchain.
12//!
13//! Includes traits for monitoring and receiving notifications of new blocks and block
14//! disconnections, transaction broadcasting, and feerate information requests.
15
16use core::{cmp, ops::Deref};
17
18use bitcoin::blockdata::transaction::Transaction;
19
20/// An interface to send a transaction to the Bitcoin network.
21pub trait BroadcasterInterface {
22	/// Sends a transaction out to (hopefully) be mined.
23	fn broadcast_transaction(&self, tx: &Transaction);
24}
25
26/// An enum that represents the speed at which we want a transaction to confirm used for feerate
27/// estimation.
28#[derive(Clone, Copy, Hash, PartialEq, Eq)]
29pub enum ConfirmationTarget {
30	/// We are happy with this transaction confirming slowly when feerate drops some.
31	Background,
32	/// We'd like this transaction to confirm without major delay, but 12-18 blocks is fine.
33	Normal,
34	/// We'd like this transaction to confirm in the next few blocks.
35	HighPriority,
36}
37
38/// A trait which should be implemented to provide feerate information on a number of time
39/// horizons.
40///
41/// Note that all of the functions implemented here *must* be reentrant-safe (obviously - they're
42/// called from inside the library in response to chain events, P2P events, or timer events).
43pub trait FeeEstimator {
44	/// Gets estimated satoshis of fee required per 1000 Weight-Units.
45	///
46	/// LDK will wrap this method and ensure that the value returned is no smaller than 253
47	/// (ie 1 satoshi-per-byte rounded up to ensure later round-downs don't put us below 1 satoshi-per-byte).
48	///
49	/// The following unit conversions can be used to convert to sats/KW:
50	///  * satoshis-per-byte * 250
51	///  * satoshis-per-kbyte / 4
52	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32;
53}
54
55/// Minimum relay fee as required by bitcoin network mempool policy.
56pub const MIN_RELAY_FEE_SAT_PER_1000_WEIGHT: u64 = 4000;
57/// Minimum feerate that takes a sane approach to bitcoind weight-to-vbytes rounding.
58/// See the following Core Lightning commit for an explanation:
59/// <https://github.com/ElementsProject/lightning/commit/2e687b9b352c9092b5e8bd4a688916ac50b44af0>
60pub const FEERATE_FLOOR_SATS_PER_KW: u32 = 253;
61
62/// Wraps a `Deref` to a `FeeEstimator` so that any fee estimations provided by it
63/// are bounded below by `FEERATE_FLOOR_SATS_PER_KW` (253 sats/KW).
64///
65/// Note that this does *not* implement [`FeeEstimator`] to make it harder to accidentally mix the
66/// two.
67pub(crate) struct LowerBoundedFeeEstimator<F: Deref>(pub F) where F::Target: FeeEstimator;
68
69impl<F: Deref> LowerBoundedFeeEstimator<F> where F::Target: FeeEstimator {
70	/// Creates a new `LowerBoundedFeeEstimator` which wraps the provided fee_estimator
71	pub fn new(fee_estimator: F) -> Self {
72		LowerBoundedFeeEstimator(fee_estimator)
73	}
74
75	pub fn bounded_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
76		cmp::max(
77			self.0.get_est_sat_per_1000_weight(confirmation_target),
78			FEERATE_FLOOR_SATS_PER_KW,
79		)
80	}
81}
82
83#[cfg(test)]
84mod tests {
85	use super::{FEERATE_FLOOR_SATS_PER_KW, LowerBoundedFeeEstimator, ConfirmationTarget, FeeEstimator};
86
87	struct TestFeeEstimator {
88		sat_per_kw: u32,
89	}
90
91	impl FeeEstimator for TestFeeEstimator {
92		fn get_est_sat_per_1000_weight(&self, _: ConfirmationTarget) -> u32 {
93			self.sat_per_kw
94		}
95	}
96
97	#[test]
98	fn test_fee_estimator_less_than_floor() {
99		let sat_per_kw = FEERATE_FLOOR_SATS_PER_KW - 1;
100		let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
101		let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
102
103		assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), FEERATE_FLOOR_SATS_PER_KW);
104	}
105
106	#[test]
107	fn test_fee_estimator_greater_than_floor() {
108		let sat_per_kw = FEERATE_FLOOR_SATS_PER_KW + 1;
109		let test_fee_estimator = &TestFeeEstimator { sat_per_kw };
110		let fee_estimator = LowerBoundedFeeEstimator::new(test_fee_estimator);
111
112		assert_eq!(fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background), sat_per_kw);
113	}
114}
rgb_lightning/chain/chaininterface.rs

rgb_lightning/chain/
chaininterface.rs
