can_send_update_fee

Author: tankyleo

lightning/src/ln/channel.rs

@@ -1112,8 +1112,6 @@ struct HTLCStats {
 	// htlc on the counterparty's commitment transaction.
 	extra_nondust_htlc_on_counterparty_tx_dust_exposure_msat: Option<u64>,
 	on_holder_tx_dust_exposure_msat: u64,
-	outbound_holding_cell_msat: u64,
-	on_holder_tx_outbound_holding_cell_htlcs_count: u32, // dust HTLCs *non*-included
 }
 
 /// A struct gathering data on a commitment, either local or remote.
@@ -4375,27 +4373,39 @@ where
 		let dust_exposure_limiting_feerate = self.get_dust_exposure_limiting_feerate(
 			&fee_estimator, funding.get_channel_type(),
 		);
-		let htlc_stats = self.get_pending_htlc_stats(funding, Some(feerate_per_kw), dust_exposure_limiting_feerate);
-		let stats = self.build_commitment_stats(funding, true, true, Some(feerate_per_kw), Some(htlc_stats.on_holder_tx_outbound_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize));
-		let holder_balance_msat = stats.local_balance_before_fee_msat - htlc_stats.outbound_holding_cell_msat;
+		let next_commitment_htlcs = self.next_commitment_htlcs(None);
+		let value_to_self_msat = self.get_next_commitment_value_to_self_msat(funding);
+		let next_commitment_stats = SpecTxBuilder {}.get_builder_stats(funding.is_outbound(), funding.get_value_satoshis(), value_to_self_msat, &next_commitment_htlcs, CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, feerate_per_kw, dust_exposure_limiting_feerate, funding.get_channel_type(), self.holder_dust_limit_satoshis, self.counterparty_dust_limit_satoshis);
 		// Note that `stats.commit_tx_fee_sat` accounts for any HTLCs that transition from non-dust to dust under a higher feerate (in the case where HTLC-transactions pay endogenous fees).
-		if holder_balance_msat < stats.commit_tx_fee_sat * 1000 + funding.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
+		if next_commitment_stats.holder_balance_msat.unwrap() < next_commitment_stats.holder_commit_tx_fee_sat * 1000 + funding.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
 			//TODO: auto-close after a number of failures?
 			log_debug!(logger, "Cannot afford to send new feerate at {}", feerate_per_kw);
 			return false;
 		}
 
 		// Note, we evaluate pending htlc "preemptive" trimmed-to-dust threshold at the proposed `feerate_per_kw`.
 		let max_dust_htlc_exposure_msat = self.get_max_dust_htlc_exposure_msat(dust_exposure_limiting_feerate);
-		if htlc_stats.on_holder_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
+		if next_commitment_stats.on_holder_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
 			log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
 			return false;
 		}
-		if htlc_stats.on_counterparty_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
+		if next_commitment_stats.on_counterparty_tx_dust_exposure_msat > max_dust_htlc_exposure_msat {
 			log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
 			return false;
 		}
 
+		#[cfg(any(test, fuzzing))]
+		{
+			let next_commitment_stats = SpecTxBuilder {}.get_builder_stats(funding.is_outbound(), funding.get_value_satoshis(), value_to_self_msat, &next_commitment_htlcs, 0, feerate_per_kw, dust_exposure_limiting_feerate, funding.get_channel_type(), self.holder_dust_limit_satoshis, self.counterparty_dust_limit_satoshis);
+			let mut predicted_htlcs = next_commitment_htlcs;
+			predicted_htlcs.sort_unstable();
+			*funding.next_local_fee.lock().unwrap() = PredictedNextFee {
+				predicted_feerate: feerate_per_kw,
+				predicted_htlcs,
+				predicted_fee_sat: next_commitment_stats.holder_commit_tx_fee_sat,
+			};
+		}
+
 		return true;
 	}
 
@@ -4786,8 +4796,6 @@ where
 		}
 
 		let mut pending_outbound_htlcs_value_msat = 0;
-		let mut outbound_holding_cell_msat = 0;
-		let mut on_holder_tx_outbound_holding_cell_htlcs_count = 0;
 		let mut pending_outbound_htlcs = self.pending_outbound_htlcs.len();
 		{
 			let counterparty_dust_limit_success_sat = htlc_success_tx_fee_sat + context.counterparty_dust_limit_satoshis;
@@ -4808,16 +4816,13 @@ where
 				if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
 					pending_outbound_htlcs += 1;
 					pending_outbound_htlcs_value_msat += amount_msat;
-					outbound_holding_cell_msat += amount_msat;
 					if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
 						on_counterparty_tx_dust_exposure_msat += amount_msat;
 					} else {
 						on_counterparty_tx_accepted_nondust_htlcs += 1;
 					}
 					if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
 						on_holder_tx_dust_exposure_msat += amount_msat;
-					} else {
-						on_holder_tx_outbound_holding_cell_htlcs_count += 1;
 					}
 				}
 			}
@@ -4855,8 +4860,6 @@ where
 			on_counterparty_tx_dust_exposure_msat,
 			extra_nondust_htlc_on_counterparty_tx_dust_exposure_msat,
 			on_holder_tx_dust_exposure_msat,
-			outbound_holding_cell_msat,
-			on_holder_tx_outbound_holding_cell_htlcs_count,
 		}
 	}