X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fchaininterface.rs;h=913fa007d378e91ba5666e3d34ae11c15010ce13;hb=61cf75265ebff493af5a04550a5ff8b250f3b2f6;hp=4204d714f1b12be5a7a1a04fed5092746562c827;hpb=db3d58c586b9f2972414a07b09980db710428c7a;p=rust-lightning

diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs
index 4204d714..913fa007 100644
--- a/lightning/src/chain/chaininterface.rs
+++ b/lightning/src/chain/chaininterface.rs
@@ -14,9 +14,18 @@
 //! 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 list of transactions out to (hopefully) be mined.
@@ -59,6 +68,11 @@ pub enum ConfirmationTarget {
 /// 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 {