Include 0FC channels in anchor channel checks

Author: tankyleo

src/event.rs

@@ -1266,7 +1266,7 @@ where
 					}
 				}
 
-				let anchor_channel = channel_type.requires_anchors_zero_fee_htlc_tx();
+				let anchor_channel = crate::requires_anchor_channel_type(&channel_type);
 				let required_reserve_sats = crate::new_channel_anchor_reserve_sats(
 					&self.config,
 					&counterparty_node_id,

src/lib.rs

@@ -163,7 +163,9 @@ use lightning_background_processor::process_events_async;
 pub use lightning_invoice;
 pub use lightning_liquidity;
 pub use lightning_types;
-use lightning_types::features::NodeFeatures as LdkNodeFeatures;
+use lightning_types::features::{
+	ChannelTypeFeatures, InitFeatures, NodeFeatures as LdkNodeFeatures,
+};
 use liquidity::LiquiditySource;
 use lnurl_auth::LnurlAuth;
 use logger::{log_debug, log_error, log_info, log_trace, LdkLogger, Logger};
@@ -219,6 +221,19 @@ impl LeakChecker {
 	}
 }
 
+fn peer_may_negotiate_anchor_channel_type(
+	config: &Config, their_init_features: &InitFeatures,
+) -> bool {
+	their_init_features.supports_anchors_zero_fee_htlc_tx()
+		|| (config.anchor_channels_config.enable_zero_fee_commitments
+			&& their_init_features.supports_anchor_zero_fee_commitments())
+}
+
+fn requires_anchor_channel_type(channel_type: &ChannelTypeFeatures) -> bool {
+	channel_type.requires_anchors_zero_fee_htlc_tx()
+		|| channel_type.requires_anchor_zero_fee_commitments()
+}
+
 /// The main interface object of LDK Node, wrapping the necessary LDK and BDK functionalities.
 ///
 /// Needs to be initialized and instantiated through [`Builder::build`].
@@ -1387,7 +1402,7 @@ impl Node {
 			.peer_by_node_id(peer_node_id)
 			.ok_or(Error::ConnectionFailed)?
 			.init_features;
-		let anchor_channel = init_features.supports_anchors_zero_fee_htlc_tx();
+		let anchor_channel = peer_may_negotiate_anchor_channel_type(&self.config, &init_features);
 		Ok(new_channel_anchor_reserve_sats(&self.config, peer_node_id, anchor_channel))
 	}
 
@@ -2450,7 +2465,7 @@ pub(crate) fn total_anchor_channels_reserve_sats(
 				.contains(&c.counterparty.node_id)
 				&& c.channel_shutdown_state
 					.map_or(true, |s| s != ChannelShutdownState::ShutdownComplete)
-				&& c.channel_type.as_ref().map_or(false, |t| t.requires_anchors_zero_fee_htlc_tx())
+				&& c.channel_type.as_ref().map_or(false, requires_anchor_channel_type)
 		})
 		.count() as u64
 		* config.anchor_channels_config.per_channel_reserve_sats

src/liquidity/service/lsps2.rs

@@ -452,18 +452,14 @@ where
 					total_anchor_channels_reserve_sats(&self.channel_manager, &self.config);
 				let spendable_amount_sats =
 					self.wallet.get_spendable_amount_sats(cur_anchor_reserve_sats).unwrap_or(0);
-				let required_funds_sats = channel_amount_sats
-					+ if init_features.supports_anchors_zero_fee_htlc_tx()
-						&& !self
-							.config
-							.anchor_channels_config
-							.trusted_peers_no_reserve
-							.contains(&their_network_key)
-					{
-						self.config.anchor_channels_config.per_channel_reserve_sats
-					} else {
-						0
-					};
+				let anchor_channel =
+					crate::peer_may_negotiate_anchor_channel_type(&self.config, &init_features);
+				let additional_reserve_required = crate::new_channel_anchor_reserve_sats(
+					&self.config,
+					&their_network_key,
+					anchor_channel,
+				);
+				let required_funds_sats = channel_amount_sats + additional_reserve_required;
 				if spendable_amount_sats < required_funds_sats {
 					log_error!(self.logger,
 						"Unable to create channel due to insufficient funds. Available: {}sats, Required: {}sats",

src/types.rs

@@ -649,7 +649,7 @@ impl ChannelDetails {
 		value: LdkChannelDetails, anchor_channels_config: &AnchorChannelsConfig,
 	) -> Self {
 		let reserve_type = value.channel_type.as_ref().map(|channel_type| {
-			if channel_type.requires_anchors_zero_fee_htlc_tx() {
+			if crate::requires_anchor_channel_type(channel_type) {
 				if anchor_channels_config
 					.trusted_peers_no_reserve
 					.contains(&value.counterparty.node_id)