-f move config value to a variation rate

Author: Antoine Riard

lightning/src/ln/channel.rs

@@ -2860,9 +2860,9 @@ impl<Signer: Sign> Channel<Signer> {
 	/// Trigger the autoclose timer if it's in the starting position
 	pub fn maybe_trigger_autoclose_timer(&mut self, current_feerate: u32, new_feerate: u32) -> bool {
 
-		// Verify the new feerate is at least superior by 30% of current feerate before to
+		// Verify the new feerate is at least superior by `autoclose_variation_rate` of current feerate before to
 		// start a autoclose timer and current feerate has fallen behind background feerate.
-		if new_feerate > current_feerate * 1300 / 1000 {
+		if new_feerate > current_feerate * self.config.autoclose_variation_rate / 1000 {
 			return false;
 		}
 
@@ -3403,7 +3403,7 @@ impl<Signer: Sign> Channel<Signer> {
 			// Again, check at each autoclose tick that mempool feerate hasn't fall back
 			// more in-sync to the current channel feerate. Otherwise, reset autoclose
 			// timer from scratch.
-			if new_feerate < self.get_feerate() * 1300 / 1000 {
+			if new_feerate < self.get_feerate() * self.config.autoclose_variation_rate / 1000 {
 				self.autoclose_timer += 1;
 			} else {
 				self.autoclose_timer = 0;
@@ -3420,8 +3420,8 @@ impl<Signer: Sign> Channel<Signer> {
 				}
 			}
 			let outbound_stats = self.get_outbound_pending_htlc_stats(None);
-			// If the channel has pending *included* HTLCs to claim on-chain and `should_autoclose`=y, close the channel
-			if (outbound_stats.on_holder_tx_included_htlcs > 0 || pending_inbound) && self.config.should_autoclose {
+			// If the channel has pending *included* HTLCs to claim on-chain and auto-close is enabled, close the channel
+			if (outbound_stats.on_holder_tx_included_htlcs > 0 || pending_inbound) && self.config.autoclose_variation_rate != 0 {
 				return Err(ChannelError::Close("Channel has time-sensitive outputs and the auto-close timer has been reached".to_owned()));
 			}
 			// Otherwise, do not reset the autoclose timer as a substantial HTLC can be committed

lightning/src/util/config.rs

@@ -246,10 +246,13 @@ pub struct ChannelConfig {
 	/// [`Normal`]: crate::chain::chaininterface::ConfirmationTarget::Normal
 	/// [`Background`]: crate::chain::chaininterface::ConfirmationTarget::Background
 	pub force_close_avoidance_max_fee_satoshis: u64,
-	/// If this is set to false, we do not auto-close channel with pending time-sensitive outputs,
-	/// of which the feerate has been detected as stalling.
-	/// Default value: true.
-	pub should_autoclose: bool,
+	/// Maximum feerate variation for a given `cltv_expiry_delta` period. Increasing the variation
+	/// rate, make the auto-close mechanism react faster to more sensitive fee spikes.
+	///
+	/// Setting the value to 0 disable auto-close.
+	///
+	/// Default value: 1300 (30%)
+	pub autoclose_variation_rate: u32,
 }
 
 impl Default for ChannelConfig {
@@ -263,7 +266,7 @@ impl Default for ChannelConfig {
 			commit_upfront_shutdown_pubkey: true,
 			max_dust_htlc_exposure_msat: 5_000_000,
 			force_close_avoidance_max_fee_satoshis: 1000,
-			should_autoclose: true,
+			autoclose_variation_rate: 1300,
 		}
 	}
 }
@@ -276,7 +279,7 @@ impl_writeable_tlv_based!(ChannelConfig, {
 	(4, announced_channel, required),
 	(6, commit_upfront_shutdown_pubkey, required),
 	(8, forwarding_fee_base_msat, required),
-	(10, should_autoclose, (default_value, true)),
+	(10, autoclose_variation_rate, (default_value, 1300)),
 });
 
 /// Top-level config which holds ChannelHandshakeLimits and ChannelConfig.