fixup! Don't include below-dust inbound HTLCs in commit tx fee calculation

Author: valentinewallace

lightning/src/ln/channel.rs

@@ -4653,7 +4653,7 @@ mod tests {
 	use ln::features::InitFeatures;
 	use ln::msgs::{OptionalField, DataLossProtect, DecodeError};
 	use ln::chan_utils;
-	use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters};
+	use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT};
 	use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
 	use chain::keysinterface::{InMemoryChannelKeys, KeysInterface};
 	use chain::transaction::OutPoint;
@@ -4737,7 +4737,7 @@ mod tests {
 	}
 
 	#[test]
-	fn test_commit_tx_fees_with_dust() {
+	fn test_holder_vs_counterparty_dust_limit() {
 		// Test that when calculating the local and remote commitment transaction fees, the correct
 		// dust limits are used.
 		let feeest = TestFeeEstimator{fee_est: 15000};
@@ -4803,6 +4803,49 @@ mod tests {
 		assert_eq!(remote_commit_tx_fee, remote_commit_fee_3_htlcs);
 	}
 
+	#[test]
+	fn test_timeout_vs_success_htlc_dust_limit() {
+		// Make sure that when `next_remote_commit_tx_fee_msat` and `next_local_commit_tx_fee_msat`
+		// calculate the real dust limits for HTLCs (i.e. the dust limit given by the counterparty
+		// *plus* the fees paid for the HTLC) they don't swap `HTLC_SUCCESS_TX_WEIGHT` for
+		// `HTLC_TIMEOUT_TX_WEIGHT`, and vice versa.
+		let fee_est = TestFeeEstimator{fee_est: 253 };
+		let secp_ctx = Secp256k1::new();
+		let seed = [42; 32];
+		let network = Network::Testnet;
+		let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
+
+		let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		let config = UserConfig::default();
+		let mut chan = Channel::<EnforcingChannelKeys>::new_outbound(&&fee_est, &&keys_provider, node_id, 10000000, 100000, 42, &config).unwrap();
+
+		let commitment_tx_fee_0_htlcs = chan.commit_tx_fee_msat(0);
+		let commitment_tx_fee_1_htlc = chan.commit_tx_fee_msat(1);
+
+		// If HTLC_SUCCESS_TX_WEIGHT and HTLC_TIMEOUT_TX_WEIGHT were swapped: then this HTLC would be
+		// counted as dust when it shouldn't be.
+		let htlc_amt_above_timeout = ((253 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + chan.holder_dust_limit_satoshis + 1) * 1000;
+		let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(htlc_amt_above_timeout, true, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
+
+		// If swapped: this HTLC would be counted as non-dust when it shouldn't be.
+		let dust_htlc_amt_below_success = ((253 * HTLC_SUCCESS_TX_WEIGHT / 1000) + chan.holder_dust_limit_satoshis - 1) * 1000;
+		let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(dust_htlc_amt_below_success, false, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
+
+		chan.channel_transaction_parameters.is_outbound_from_holder = false;
+
+		// If swapped: this HTLC would be counted as non-dust when it shouldn't be.
+		let dust_htlc_amt_above_timeout = ((253 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + chan.counterparty_dust_limit_satoshis + 1) * 1000;
+		let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(dust_htlc_amt_above_timeout, true, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
+
+		// If swapped: this HTLC would be counted as dust when it shouldn't be.
+		let htlc_amt_below_success = ((253 * HTLC_SUCCESS_TX_WEIGHT / 1000) + chan.counterparty_dust_limit_satoshis - 1) * 1000;
+		let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(htlc_amt_below_success, false, None);
+		assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
+	}
+
 	#[test]
 	fn channel_reestablish_no_updates() {
 		let feeest = TestFeeEstimator{fee_est: 15000};