From 2dbe461743604d8ce8219e99ea337dd7b8b498df Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Sat, 26 Jun 2021 17:19:34 +0000 Subject: [PATCH] Correct feerate units Lightning, unlike every other Bitcoin-related protocol or API, uses satoshis-per-1000-weight, instead of satoshis-per-1000-virtual-bytes. This requires a division by 4 to calculate the correct fees when passing Bitcoin Core fees into LDK. --- src/bitcoind_client.rs | 20 +++++++++++--------- src/convert.rs | 11 ++++++++--- 2 files changed, 19 insertions(+), 12 deletions(-) diff --git a/src/bitcoind_client.rs b/src/bitcoind_client.rs index 56b7f1a..90552d9 100644 --- a/src/bitcoind_client.rs +++ b/src/bitcoind_client.rs @@ -60,6 +60,9 @@ impl BlockSource for &BitcoindClient { } } +/// The minimum feerate we are allowed to send, as specify by LDK. +const MIN_FEERATE: u32 = 253; + impl BitcoindClient { pub async fn new( host: String, port: u16, rpc_user: String, rpc_password: String, @@ -76,7 +79,7 @@ impl BitcoindClient { "Failed to make initial call to bitcoind - please check your RPC user/password and access settings") })?; let mut fees: HashMap = HashMap::new(); - fees.insert(Target::Background, AtomicU32::new(253)); + fees.insert(Target::Background, AtomicU32::new(MIN_FEERATE)); fees.insert(Target::Normal, AtomicU32::new(2000)); fees.insert(Target::HighPriority, AtomicU32::new(5000)); let client = Self { @@ -111,12 +114,11 @@ impl BitcoindClient { ) .await .unwrap(); - match resp.feerate { - Some(fee) => fee, - None => 253, + match resp.feerate_sat_per_kw { + Some(feerate) => std::cmp::max(feerate, MIN_FEERATE), + None => MIN_FEERATE, } }; - // if background_estimate. let normal_estimate = { let mut rpc = rpc_client.lock().await; @@ -129,8 +131,8 @@ impl BitcoindClient { ) .await .unwrap(); - match resp.feerate { - Some(fee) => fee, + match resp.feerate_sat_per_kw { + Some(feerate) => std::cmp::max(feerate, MIN_FEERATE), None => 2000, } }; @@ -147,8 +149,8 @@ impl BitcoindClient { .await .unwrap(); - match resp.feerate { - Some(fee) => fee, + match resp.feerate_sat_per_kw { + Some(feerate) => std::cmp::max(feerate, MIN_FEERATE), None => 5000, } }; diff --git a/src/convert.rs b/src/convert.rs index a652980..6403923 100644 --- a/src/convert.rs +++ b/src/convert.rs @@ -51,7 +51,7 @@ impl TryInto for JsonResponse { } pub struct FeeResponse { - pub feerate: Option, + pub feerate_sat_per_kw: Option, pub errored: bool, } @@ -61,8 +61,13 @@ impl TryInto for JsonResponse { let errored = !self.0["errors"].is_null(); Ok(FeeResponse { errored, - feerate: match self.0["feerate"].as_f64() { - Some(fee) => Some((fee * 100_000_000.0).round() as u32), + feerate_sat_per_kw: match self.0["feerate"].as_f64() { + // Bitcoin Core gives us a feerate in BTC/KvB, which we need to convert to + // satoshis/KW. Thus, we first multiply by 10^8 to get satoshis, then divide by 4 + // to convert virtual-bytes into weight units. + Some(feerate_btc_per_kvbyte) => { + Some((feerate_btc_per_kvbyte * 100_000_000.0 / 4.0).round() as u32) + } None => None, }, }) -- 2.30.2