Allow configuring different max fee rate from peer

Author: benthecarman

lightning/src/ln/channel.rs

@@ -2144,19 +2144,20 @@ impl<SP: Deref> Channel<SP> where
 	<SP::Target as SignerProvider>::Signer: WriteableEcdsaChannelSigner
 {
 	fn check_remote_fee<F: Deref, L: Deref>(
-		channel_type: &ChannelTypeFeatures, fee_estimator: &LowerBoundedFeeEstimator<F>,
-		feerate_per_kw: u32, cur_feerate_per_kw: Option<u32>, logger: &L
+		channel_type: &ChannelTypeFeatures, config: &ChannelConfig,
+		fee_estimator: &LowerBoundedFeeEstimator<F>, feerate_per_kw: u32,
+		cur_feerate_per_kw: Option<u32>, logger: &L
 	) -> Result<(), ChannelError> where F::Target: FeeEstimator, L::Target: Logger,
 	{
 		// We only bound the fee updates on the upper side to prevent completely absurd feerates,
-		// always accepting up to 25 sat/vByte or 10x our fee estimator's "High Priority" fee.
+		// by default accepting up to 25 sat/vByte or 10x our fee estimator's "High Priority" fee.
 		// We generally don't care too much if they set the feerate to something very high, but it
 		// could result in the channel being useless due to everything being dust. This doesn't
 		// apply to channels supporting anchor outputs since HTLC transactions are pre-signed with a
 		// zero fee, so their fee is no longer considered to determine dust limits.
 		if !channel_type.supports_anchors_zero_fee_htlc_tx() {
-			let upper_limit = cmp::max(250 * 25,
-				fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64 * 10);
+			let upper_limit = cmp::max(config.base_max_accepted_fee_rate as u64,
+				fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64 * config.max_accepted_fee_rate_multiplier as u64);
 			if feerate_per_kw as u64 > upper_limit {
 				return Err(ChannelError::Close(format!("Peer's feerate much too high. Actual: {}. Our expected upper limit: {}", feerate_per_kw, upper_limit)));
 			}
@@ -3854,7 +3855,7 @@ impl<SP: Deref> Channel<SP> where
 		if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
 			return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish".to_owned()));
 		}
-		Channel::<SP>::check_remote_fee(&self.context.channel_type, fee_estimator, msg.feerate_per_kw, Some(self.context.feerate_per_kw), logger)?;
+		Channel::<SP>::check_remote_fee(&self.context.channel_type, &self.context.config(), fee_estimator, msg.feerate_per_kw, Some(self.context.feerate_per_kw), logger)?;
 		let feerate_over_dust_buffer = msg.feerate_per_kw > self.context.get_dust_buffer_feerate(None);
 
 		self.context.pending_update_fee = Some((msg.feerate_per_kw, FeeUpdateState::RemoteAnnounced));
@@ -6289,7 +6290,7 @@ impl<SP: Deref> InboundV1Channel<SP> where SP::Target: SignerProvider {
 		if msg.htlc_minimum_msat >= full_channel_value_msat {
 			return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
 		}
-		Channel::<SP>::check_remote_fee(&channel_type, fee_estimator, msg.feerate_per_kw, None, logger)?;
+		Channel::<SP>::check_remote_fee(&channel_type, &config.channel_config, fee_estimator, msg.feerate_per_kw, None, logger)?;
 
 		let max_counterparty_selected_contest_delay = u16::min(config.channel_handshake_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
 		if msg.to_self_delay > max_counterparty_selected_contest_delay {
@@ -7642,7 +7643,7 @@ mod tests {
 	use crate::ln::PaymentHash;
 	use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
 	use crate::ln::channel::InitFeatures;
-	use crate::ln::channel::{Channel, ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, commit_tx_fee_msat};
+	use crate::ln::channel::{Channel, ChannelConfig, ChannelState, InboundHTLCOutput, OutboundV1Channel, InboundV1Channel, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, commit_tx_fee_msat};
 	use crate::ln::channel::{MAX_FUNDING_SATOSHIS_NO_WUMBO, TOTAL_BITCOIN_SUPPLY_SATOSHIS, MIN_THEIR_CHAN_RESERVE_SATOSHIS};
 	use crate::ln::features::ChannelTypeFeatures;
 	use crate::ln::msgs::{ChannelUpdate, DecodeError, UnsignedChannelUpdate, MAX_VALUE_MSAT};
@@ -7691,7 +7692,7 @@ mod tests {
 		let fee_est = TestFeeEstimator { fee_est: 42 };
 		let bounded_fee_estimator = LowerBoundedFeeEstimator::new(&fee_est);
 		assert!(Channel::<&TestKeysInterface>::check_remote_fee(
-			&ChannelTypeFeatures::only_static_remote_key(), &bounded_fee_estimator,
+			&ChannelTypeFeatures::only_static_remote_key(), &ChannelConfig::default(), &bounded_fee_estimator,
 			u32::max_value(), None, &&test_utils::TestLogger::new()).is_err());
 	}
 

lightning/src/util/config.rs

@@ -485,6 +485,24 @@ pub struct ChannelConfig {
 	/// [`PaymentClaimable::counterparty_skimmed_fee_msat`]: crate::events::Event::PaymentClaimable::counterparty_skimmed_fee_msat
 	//  TODO: link to bLIP when it's merged
 	pub accept_underpaying_htlcs: bool,
+
+	/// When checking our channel counterparty's fee rate, we will allow any value that is up to the greater
+	/// between [`ChannelConfig::base_max_accepted_fee_rate`] and [`ChannelConfig::max_accepted_fee_rate_multiplier`]
+	/// times our [`HighPriority`] estimated feerate. This is only used for non-anchor channels.
+	///
+	/// Default value: 25 sat/vbyte.
+	///
+	/// [`HighPriority`]: crate::chain::chaininterface::ConfirmationTarget::HighPriority
+	pub base_max_accepted_fee_rate: u32,
+
+	/// When checking our channel counterparty's fee rate, we will allow any value that is up to the greater
+	/// between [`ChannelConfig::base_max_accepted_fee_rate`] and [`ChannelConfig::max_accepted_fee_rate_multiplier`]
+	/// times our [`HighPriority`] estimated feerate. This is only used for non-anchor channels.
+	///
+	/// Default value: 10.
+	///
+	/// [`HighPriority`]: crate::chain::chaininterface::ConfirmationTarget::HighPriority
+	pub max_accepted_fee_rate_multiplier: u32,
 }
 
 impl ChannelConfig {
@@ -518,6 +536,8 @@ impl Default for ChannelConfig {
 			max_dust_htlc_exposure: MaxDustHTLCExposure::FeeRateMultiplier(5000),
 			force_close_avoidance_max_fee_satoshis: 1000,
 			accept_underpaying_htlcs: false,
+			base_max_accepted_fee_rate: 25 * 250, // 25 sat/vbyte
+			max_accepted_fee_rate_multiplier: 10,
 		}
 	}
 }
@@ -539,6 +559,8 @@ impl crate::util::ser::Writeable for ChannelConfig {
 			// LegacyChannelConfig. To make sure that serialization is not compatible with this one, we use
 			// the next required type of 10, which if seen by the old serialization will always fail.
 			(10, self.force_close_avoidance_max_fee_satoshis, required),
+			(11, self.base_max_accepted_fee_rate, required),
+			(13, self.max_accepted_fee_rate_multiplier, required),
 		});
 		Ok(())
 	}
@@ -553,6 +575,8 @@ impl crate::util::ser::Readable for ChannelConfig {
 		let mut max_dust_htlc_exposure_msat = None;
 		let mut max_dust_htlc_exposure_enum = None;
 		let mut force_close_avoidance_max_fee_satoshis = 1000;
+		let mut base_max_accepted_fee_rate = 25 * 250;
+		let mut max_accepted_fee_rate_multiplier = 10;
 		read_tlv_fields!(reader, {
 			(0, forwarding_fee_proportional_millionths, required),
 			(1, accept_underpaying_htlcs, (default_value, false)),
@@ -562,6 +586,8 @@ impl crate::util::ser::Readable for ChannelConfig {
 			// Has always been written, but became optionally read in 0.0.116
 			(6, max_dust_htlc_exposure_msat, option),
 			(10, force_close_avoidance_max_fee_satoshis, required),
+			(11, base_max_accepted_fee_rate, (default_value, 25 * 250 as u32)),
+			(13, max_accepted_fee_rate_multiplier, (default_value, 10_u32)),
 		});
 		let max_dust_htlc_fixed_limit = max_dust_htlc_exposure_msat.unwrap_or(5_000_000);
 		let max_dust_htlc_exposure_msat = max_dust_htlc_exposure_enum
@@ -573,6 +599,8 @@ impl crate::util::ser::Readable for ChannelConfig {
 			cltv_expiry_delta,
 			max_dust_htlc_exposure: max_dust_htlc_exposure_msat,
 			force_close_avoidance_max_fee_satoshis,
+			base_max_accepted_fee_rate,
+			max_accepted_fee_rate_multiplier,
 		})
 	}
 }
@@ -666,6 +694,8 @@ impl crate::util::ser::Readable for LegacyChannelConfig {
 		let mut commit_upfront_shutdown_pubkey = false;
 		let mut forwarding_fee_base_msat = 0;
 		let mut max_dust_htlc_exposure_enum = None;
+		let mut base_max_accepted_fee_rate = 25 * 250;
+		let mut max_accepted_fee_rate_multiplier = 10;
 		read_tlv_fields!(reader, {
 			(0, forwarding_fee_proportional_millionths, required),
 			// Has always been written, but became optionally read in 0.0.116
@@ -676,6 +706,8 @@ impl crate::util::ser::Readable for LegacyChannelConfig {
 			(5, max_dust_htlc_exposure_enum, option),
 			(6, commit_upfront_shutdown_pubkey, required),
 			(8, forwarding_fee_base_msat, required),
+			(11, base_max_accepted_fee_rate, (default_value, 25 * 250 as u32)),
+			(13, max_accepted_fee_rate_multiplier, (default_value, 10_u32)),
 		});
 		let max_dust_htlc_exposure_msat_fixed_limit =
 			max_dust_htlc_exposure_msat_fixed_limit.unwrap_or(5_000_000);
@@ -689,6 +721,8 @@ impl crate::util::ser::Readable for LegacyChannelConfig {
 				force_close_avoidance_max_fee_satoshis,
 				forwarding_fee_base_msat,
 				accept_underpaying_htlcs: false,
+				base_max_accepted_fee_rate,
+				max_accepted_fee_rate_multiplier,
 			},
 			announced_channel,
 			commit_upfront_shutdown_pubkey,