Add chain syncing via compact block filters (BIP 157)

Cargo.toml

@@ -58,6 +58,7 @@ bdk_chain = { version = "0.23.3", default-features = false, features = ["std"] }
 bdk_esplora = { version = "0.22.2", default-features = false, features = ["async-https-rustls", "tokio"]}
 bdk_electrum = { version = "0.24.0", default-features = false, features = ["use-rustls-ring"]}
 bdk_wallet = { version = "3.1.0", default-features = false, features = ["std", "keys-bip39"]}
+bip157 = { version = "0.6.1", default-features = false }
 
 bitreq = { version = "0.3", default-features = false, features = ["async-https", "json-using-serde"] }
 rustls = { version = "0.23", default-features = false }

src/builder.rs

@@ -45,7 +45,7 @@ use lightning::util::sweep::OutputSweeper;
 use lightning_dns_resolver::OMDomainResolver;
 use vss_client::headers::VssHeaderProvider;
 
-use crate::chain::ChainSource;
+use crate::chain::{CbfFeeSourceConfig, ChainSource};
 use crate::config::{
 	default_user_config, may_announce_channel, AnnounceError, AsyncPaymentsRole,
 	BitcoindRestClientConfig, Config, ElectrumSyncConfig, EsploraSyncConfig, HRNResolverConfig,
@@ -112,6 +112,10 @@ enum ChainDataSourceConfig {
 		rest_client_config: Option<BitcoindRestClientConfig>,
 		wallet_rescan_from_height: Option<u32>,
 	},
+	Cbf {
+		peers: Vec<String>,
+		fee_source_config: Option<CbfFeeSourceConfig>,
+	},
 }
 
 #[derive(Debug, Clone)]
@@ -396,6 +400,19 @@ impl NodeBuilder {
 		self
 	}
 
+	/// Configures the [`Node`] instance to source chain data via compact block filters
+	/// (BIP157/BIP158), connecting to the given peers (`ip:port`).
+	///
+	/// `fee_source_config` optionally delegates fee estimation to an Esplora or Electrum server;
+	/// if `None`, fee rates are derived from recent blocks.
+	pub fn set_chain_source_cbf(
+		&mut self, peers: Vec<String>, fee_source_config: Option<CbfFeeSourceConfig>,
+	) -> &mut Self {
+		self.chain_data_source_config =
+			Some(ChainDataSourceConfig::Cbf { peers, fee_source_config });
+		self
+	}
+
 	/// Configures the [`Node`] instance to connect to a Bitcoin Core node via RPC.
 	///
 	/// This method establishes an RPC connection that enables all essential chain operations including
@@ -1514,6 +1531,18 @@ fn build_with_store_internal(
 				Arc::clone(&node_metrics),
 			)
 		},
+		Some(ChainDataSourceConfig::Cbf { peers, fee_source_config }) => ChainSource::new_cbf(
+			peers.clone(),
+			fee_source_config.clone(),
+			Arc::clone(&runtime),
+			Arc::clone(&fee_estimator),
+			Arc::clone(&tx_broadcaster),
+			Arc::clone(&kv_store),
+			Arc::clone(&config),
+			Arc::clone(&logger),
+			Arc::clone(&node_metrics),
+		)
+		.map_err(|_| BuildError::ChainSourceSetupFailed)?,
 		Some(ChainDataSourceConfig::Bitcoind {
 			rpc_host,
 			rpc_port,

src/chain/bitcoind.rs

@@ -1458,13 +1458,38 @@ pub(crate) enum FeeRateEstimationMode {
 	Conservative,
 }
 
+#[derive(Clone)]
 pub(crate) struct ChainListener {
 	pub(crate) onchain_wallet: Arc<Wallet>,
 	pub(crate) channel_manager: Arc<ChannelManager>,
 	pub(crate) chain_monitor: Arc<ChainMonitor>,
 	pub(crate) output_sweeper: Arc<Sweeper>,
 }
 
+impl ChainListener {
+	pub(crate) fn get_best_block(&self) -> BlockLocator {
+		let candidates = [
+			self.onchain_wallet.current_best_block(),
+			self.channel_manager.current_best_block(),
+			self.output_sweeper.current_best_block(),
+		];
+		let mut min = candidates.into_iter().min_by_key(|b| b.height).expect("non-empty");
+		if let Some(worst_monitor) = self
+			.chain_monitor
+			.list_monitors()
+			.iter()
+			.flat_map(|id| self.chain_monitor.get_monitor(*id))
+			.map(|m| m.current_best_block())
+			.min_by_key(|b| b.height)
+		{
+			if worst_monitor.height < min.height {
+				min = worst_monitor;
+			}
+		}
+		min
+	}
+}
+
 impl Listen for ChainListener {
 	fn filtered_block_connected(
 		&self, header: &bitcoin::block::Header,