WORKAROUND: Patch commit_tx_fee_sat until COMMITMENT_TX_BASE_WEIGHT made anchor-aware

Author: ksedgwic

lightning/src/ln/channel.rs

@@ -1320,7 +1320,7 @@ impl<Signer: Sign> Channel<Signer> {
 			broadcaster_max_commitment_tx_output.1 = cmp::max(broadcaster_max_commitment_tx_output.1, value_to_remote_msat as u64);
 		}
 
-		let total_fee_sat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, included_non_dust_htlcs.len());
+		let total_fee_sat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, included_non_dust_htlcs.len(), self.channel_transaction_parameters.opt_anchors.is_some());
 		let (value_to_self, value_to_remote) = if self.is_outbound() {
 			(value_to_self_msat / 1000 - total_fee_sat as i64, value_to_remote_msat / 1000)
 		} else {
@@ -2167,8 +2167,8 @@ impl<Signer: Sign> Channel<Signer> {
 	// Get the fee cost in SATS of a commitment tx with a given number of HTLC outputs.
 	// Note that num_htlcs should not include dust HTLCs.
 	#[inline]
-	fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize) -> u64 {
-		feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000
+	fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 {
+		feerate_per_kw as u64 * (if opt_anchors { 1124 } else { COMMITMENT_TX_BASE_WEIGHT} + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000
 	}
 
 	// Get the commitment tx fee for the local's (i.e. our) next commitment transaction based on the
@@ -3151,7 +3151,7 @@ impl<Signer: Sign> Channel<Signer> {
 		let outbound_stats = self.get_outbound_pending_htlc_stats(Some(feerate_per_kw));
 		let keys = if let Ok(keys) = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number) { keys } else { return None; };
 		let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger);
-		let buffer_fee_msat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize) * 1000;
+		let buffer_fee_msat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.opt_anchors()) * 1000;
 		let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat;
 		if holder_balance_msat < buffer_fee_msat  + self.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
 			//TODO: auto-close after a number of failures?