Add timeout for Lightning syncing

.. even though we don't expect this to block, we're better safe than
sorry and start to introduce timeouts for any calls we make to remote
servers.

Author: tnull

bindings/ldk_node.udl

@@ -162,6 +162,7 @@ enum NodeError {
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",
 	"TxSyncFailed",
+	"TxSyncTimeout",
 	"GossipUpdateFailed",
 	"LiquidityRequestFailed",
 	"InvalidAddress",

src/config.rs

@@ -49,6 +49,9 @@ pub(crate) const WALLET_SYNC_INTERVAL_MINIMUM_SECS: u64 = 10;
 // The timeout after which we abort a wallet syncing operation.
 pub(crate) const BDK_WALLET_SYNC_TIMEOUT_SECS: u64 = 90;
 
+// The timeout after which we abort a wallet syncing operation.
+pub(crate) const LDK_WALLET_SYNC_TIMEOUT_SECS: u64 = 30;
+
 // The length in bytes of our wallets' keys seed.
 pub(crate) const WALLET_KEYS_SEED_LEN: usize = 64;
 

src/error.rs

@@ -43,6 +43,8 @@ pub enum Error {
 	MessageSigningFailed,
 	/// A transaction sync operation failed.
 	TxSyncFailed,
+	/// A transaction sync operation timed out.
+	TxSyncTimeout,
 	/// A gossip updating operation failed.
 	GossipUpdateFailed,
 	/// A liquidity request operation failed.
@@ -118,6 +120,7 @@ impl fmt::Display for Error {
 			Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
 			Self::MessageSigningFailed => write!(f, "Failed to sign given message."),
 			Self::TxSyncFailed => write!(f, "Failed to sync transactions."),
+			Self::TxSyncTimeout => write!(f, "Syncing transactions timed out."),
 			Self::GossipUpdateFailed => write!(f, "Failed to update gossip data."),
 			Self::LiquidityRequestFailed => write!(f, "Failed to request inbound liquidity."),
 			Self::InvalidAddress => write!(f, "The given address is invalid."),

src/lib.rs

@@ -123,8 +123,8 @@ pub use builder::BuildError;
 pub use builder::NodeBuilder as Builder;
 
 use config::{
-	default_user_config, NODE_ANN_BCAST_INTERVAL, PEER_RECONNECTION_INTERVAL,
-	RESOLVED_CHANNEL_MONITOR_ARCHIVAL_INTERVAL, RGS_SYNC_INTERVAL,
+	default_user_config, LDK_WALLET_SYNC_TIMEOUT_SECS, NODE_ANN_BCAST_INTERVAL,
+	PEER_RECONNECTION_INTERVAL, RESOLVED_CHANNEL_MONITOR_ARCHIVAL_INTERVAL, RGS_SYNC_INTERVAL,
 	WALLET_SYNC_INTERVAL_MINIMUM_SECS,
 };
 use connection::ConnectionManager;
@@ -377,25 +377,31 @@ impl Node {
 							&*sync_sweeper as &(dyn Confirm + Sync + Send),
 						];
 						let now = Instant::now();
-						match tx_sync.sync(confirmables).await {
-							Ok(()) => {
-								log_trace!(
-								sync_logger,
-								"Background sync of Lightning wallet finished in {}ms.",
-								now.elapsed().as_millis()
-								);
-								let unix_time_secs_opt =
-									SystemTime::now().duration_since(UNIX_EPOCH).ok().map(|d| d.as_secs());
-								*sync_wallet_timestamp.write().unwrap() = unix_time_secs_opt;
-
-								periodically_archive_fully_resolved_monitors(
-									Arc::clone(&archive_cman),
-									Arc::clone(&archive_cmon),
-									Arc::clone(&sync_monitor_archival_height)
-								);
+						let timeout_fut = tokio::time::timeout(Duration::from_secs(LDK_WALLET_SYNC_TIMEOUT_SECS), tx_sync.sync(confirmables));
+						match timeout_fut.await {
+							Ok(res) => match res {
+								Ok(()) => {
+									log_trace!(
+										sync_logger,
+										"Background sync of Lightning wallet finished in {}ms.",
+										now.elapsed().as_millis()
+										);
+									let unix_time_secs_opt =
+										SystemTime::now().duration_since(UNIX_EPOCH).ok().map(|d| d.as_secs());
+									*sync_wallet_timestamp.write().unwrap() = unix_time_secs_opt;
+
+									periodically_archive_fully_resolved_monitors(
+										Arc::clone(&archive_cman),
+										Arc::clone(&archive_cmon),
+										Arc::clone(&sync_monitor_archival_height)
+									);
+								}
+								Err(e) => {
+									log_error!(sync_logger, "Background sync of Lightning wallet failed: {}", e)
+								}
 							}
 							Err(e) => {
-								log_error!(sync_logger, "Background sync of Lightning wallet failed: {}", e)
+								log_error!(sync_logger, "Background sync of Lightning wallet timed out: {}", e)
 							}
 						}
 					}
@@ -1167,6 +1173,8 @@ impl Node {
 			tokio::runtime::Builder::new_multi_thread().enable_all().build().unwrap().block_on(
 				async move {
 					let now = Instant::now();
+					// We don't add an additional timeout here, as `Wallet::sync` already returns
+					// after a timeout.
 					match wallet.sync().await {
 						Ok(()) => {
 							log_info!(
@@ -1187,6 +1195,8 @@ impl Node {
 					};
 
 					let now = Instant::now();
+					// We don't add an additional timeout here, as
+					// `FeeEstimator::update_fee_estimates` already returns after a timeout.
 					match fee_estimator.update_fee_estimates().await {
 						Ok(()) => {
 							log_info!(
@@ -1207,30 +1217,40 @@ impl Node {
 					}
 
 					let now = Instant::now();
-					match tx_sync.sync(confirmables).await {
-						Ok(()) => {
-							log_info!(
-								sync_logger,
-								"Sync of Lightning wallet finished in {}ms.",
-								now.elapsed().as_millis()
-							);
+					let tx_sync_timeout_fut = tokio::time::timeout(
+						Duration::from_secs(LDK_WALLET_SYNC_TIMEOUT_SECS),
+						tx_sync.sync(confirmables),
+					);
+					match tx_sync_timeout_fut.await {
+						Ok(res) => match res {
+							Ok(()) => {
+								log_info!(
+									sync_logger,
+									"Sync of Lightning wallet finished in {}ms.",
+									now.elapsed().as_millis()
+								);
 
-							let unix_time_secs_opt = SystemTime::now()
-								.duration_since(UNIX_EPOCH)
-								.ok()
-								.map(|d| d.as_secs());
-							*sync_wallet_timestamp.write().unwrap() = unix_time_secs_opt;
+								let unix_time_secs_opt = SystemTime::now()
+									.duration_since(UNIX_EPOCH)
+									.ok()
+									.map(|d| d.as_secs());
+								*sync_wallet_timestamp.write().unwrap() = unix_time_secs_opt;
 
-							periodically_archive_fully_resolved_monitors(
-								archive_cman,
-								archive_cmon,
-								sync_monitor_archival_height,
-							);
-							Ok(())
+								periodically_archive_fully_resolved_monitors(
+									archive_cman,
+									archive_cmon,
+									sync_monitor_archival_height,
+								);
+								Ok(())
+							},
+							Err(e) => {
+								log_error!(sync_logger, "Sync of Lightning wallet failed: {}", e);
+								Err(e.into())
+							},
 						},
 						Err(e) => {
-							log_error!(sync_logger, "Sync of Lightning wallet failed: {}", e);
-							Err(e.into())
+							log_error!(sync_logger, "Sync of Lightning wallet timed out: {}", e);
+							Err(Error::TxSyncTimeout)
 						},
 					}
 				},