Add new payment type and metadata bytes

Adds two new payment `Method`s for identifying payments with custom
`min_final_cltv_expiry_delta` as payments with LDK or user payment
hashes.

The `min_final_cltv_expiry_delta` value is packed into the first 2
bytes of the expiry timestamp in the payment secret metadata.

Author: dunxen

fuzz/src/chanmon_consistency.rs

@@ -340,7 +340,7 @@ fn get_payment_secret_hash(dest: &ChanMan, payment_id: &mut u8) -> Option<(Payme
 	let mut payment_hash;
 	for _ in 0..256 {
 		payment_hash = PaymentHash(Sha256::hash(&[*payment_id; 1]).into_inner());
-		if let Ok(payment_secret) = dest.create_inbound_payment_for_hash(payment_hash, None, 3600) {
+		if let Ok(payment_secret) = dest.create_inbound_payment_for_hash(payment_hash, None, 3600, None) {
 			return Some((payment_secret, payment_hash));
 		}
 		*payment_id = payment_id.wrapping_add(1);

fuzz/src/full_stack.rs

@@ -605,7 +605,7 @@ pub fn do_test(data: &[u8], logger: &Arc<dyn Logger>) {
 				let payment_hash = PaymentHash(Sha256::from_engine(sha).into_inner());
 				// Note that this may fail - our hashes may collide and we'll end up trying to
 				// double-register the same payment_hash.
-				let _ = channelmanager.create_inbound_payment_for_hash(payment_hash, None, 1);
+				let _ = channelmanager.create_inbound_payment_for_hash(payment_hash, None, 1, None);
 			},
 			9 => {
 				for payment in payments_received.drain(..) {

lightning-invoice/src/utils.rs

@@ -166,6 +166,7 @@ where
 				.duration_since(UNIX_EPOCH)
 				.expect("Time must be > 1970")
 				.as_secs(),
+			min_final_cltv_expiry_delta,
 		)
 		.map_err(|_| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 		(payment_hash, payment_secret)
@@ -179,6 +180,7 @@ where
 				.duration_since(UNIX_EPOCH)
 				.expect("Time must be > 1970")
 				.as_secs(),
+			min_final_cltv_expiry_delta,
 		)
 		.map_err(|_| SignOrCreationError::CreationError(CreationError::InvalidAmount))?
 	};
@@ -397,7 +399,7 @@ fn _create_invoice_from_channelmanager_and_duration_since_epoch<M: Deref, T: Der
 	// `create_inbound_payment` only returns an error if the amount is greater than the total bitcoin
 	// supply.
 	let (payment_hash, payment_secret) = channelmanager
-		.create_inbound_payment(amt_msat, invoice_expiry_delta_secs)
+		.create_inbound_payment(amt_msat, invoice_expiry_delta_secs, min_final_cltv_expiry_delta)
 		.map_err(|()| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 	_create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash(
 		channelmanager, node_signer, logger, network, amt_msat, description, duration_since_epoch,
@@ -424,7 +426,8 @@ pub fn create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_
 		L::Target: Logger,
 {
 	let payment_secret = channelmanager
-		.create_inbound_payment_for_hash(payment_hash,amt_msat, invoice_expiry_delta_secs)
+		.create_inbound_payment_for_hash(payment_hash, amt_msat, invoice_expiry_delta_secs,
+			min_final_cltv_expiry_delta)
 		.map_err(|()| SignOrCreationError::CreationError(CreationError::InvalidAmount))?;
 	_create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_hash(
 		channelmanager, node_signer, logger, network, amt_msat,
@@ -1170,7 +1173,7 @@ mod test {
 		create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001);
 
 		let payment_amt = 20_000;
-		let (payment_hash, _payment_secret) = nodes[1].node.create_inbound_payment(Some(payment_amt), 3600).unwrap();
+		let (payment_hash, _payment_secret) = nodes[1].node.create_inbound_payment(Some(payment_amt), 3600, None).unwrap();
 		let route_hints = vec![
 			nodes[1].node.get_phantom_route_hints(),
 			nodes[2].node.get_phantom_route_hints(),

lightning/src/ln/channelmanager.rs

@@ -1914,6 +1914,7 @@ where
 		// final_expiry_too_soon
 		// We have to have some headroom to broadcast on chain if we have the preimage, so make sure
 		// we have at least HTLC_FAIL_BACK_BUFFER blocks to go.
+		//
 		// Also, ensure that, in the case of an unknown preimage for the received payment hash, our
 		// payment logic has enough time to fail the HTLC backward before our onchain logic triggers a
 		// channel closure (see HTLC_FAIL_BACK_BUFFER rationale).
@@ -3184,10 +3185,21 @@ where
 												let payment_preimage = match inbound_payment::verify(payment_hash, &payment_data, self.highest_seen_timestamp.load(Ordering::Acquire) as u64, &self.inbound_payment_key, &self.logger) {
 													Ok(payment_preimage) => payment_preimage,
 													Err(()) => {
+														log_trace!(self.logger, "Failing new HTLC with payment_hash {} as payment verification failed", log_bytes!(payment_hash.0));
 														fail_htlc!(claimable_htlc, payment_hash);
 														continue
 													}
 												};
+												if let Some(min_final_cltv_expiry_delta) = inbound_payment::get_custom_min_final_cltv_expiry_delta(
+													payment_data.payment_secret, &self.inbound_payment_key) {
+													let expected_min_expiry_height = (self.current_best_block().height() + min_final_cltv_expiry_delta as u32) as u64;
+													if (cltv_expiry as u64) < expected_min_expiry_height {
+														log_trace!(self.logger, "Failing new HTLC with payment_hash {} as its CLTV expiry was too soon (had {}, earliest expected {})",
+															log_bytes!(payment_hash.0), cltv_expiry, expected_min_expiry_height);
+														fail_htlc!(claimable_htlc, payment_hash);
+														continue;
+													}
+												}
 												check_total_value!(payment_data, payment_preimage);
 											},
 											OnionPayload::Spontaneous(preimage) => {
@@ -5273,12 +5285,18 @@ where
 	///
 	/// Errors if `min_value_msat` is greater than total bitcoin supply.
 	///
+	/// If `min_final_cltv_expiry_delta` is set to some value, then the payment will not be receivable
+	/// on versions of LDK prior to 0.0.114.
+	///
 	/// [`claim_funds`]: Self::claim_funds
 	/// [`PaymentClaimable`]: events::Event::PaymentClaimable
 	/// [`PaymentClaimable::payment_preimage`]: events::Event::PaymentClaimable::payment_preimage
 	/// [`create_inbound_payment_for_hash`]: Self::create_inbound_payment_for_hash
-	pub fn create_inbound_payment(&self, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32) -> Result<(PaymentHash, PaymentSecret), ()> {
-		inbound_payment::create(&self.inbound_payment_key, min_value_msat, invoice_expiry_delta_secs, &self.entropy_source, self.highest_seen_timestamp.load(Ordering::Acquire) as u64)
+	pub fn create_inbound_payment(&self, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32,
+		min_final_cltv_expiry_delta: Option<u16>) -> Result<(PaymentHash, PaymentSecret), ()> {
+		inbound_payment::create(&self.inbound_payment_key, min_value_msat, invoice_expiry_delta_secs,
+			&self.entropy_source, self.highest_seen_timestamp.load(Ordering::Acquire) as u64,
+			min_final_cltv_expiry_delta)
 	}
 
 	/// Legacy version of [`create_inbound_payment`]. Use this method if you wish to share
@@ -5339,10 +5357,16 @@ where
 	///
 	/// Errors if `min_value_msat` is greater than total bitcoin supply.
 	///
+	/// If `min_final_cltv_expiry_delta` is set to some value, then the payment will not be receivable
+	/// on versions of LDK prior to 0.0.114.
+	///
 	/// [`create_inbound_payment`]: Self::create_inbound_payment
 	/// [`PaymentClaimable`]: events::Event::PaymentClaimable
-	pub fn create_inbound_payment_for_hash(&self, payment_hash: PaymentHash, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32) -> Result<PaymentSecret, ()> {
-		inbound_payment::create_from_hash(&self.inbound_payment_key, min_value_msat, payment_hash, invoice_expiry_delta_secs, self.highest_seen_timestamp.load(Ordering::Acquire) as u64)
+	pub fn create_inbound_payment_for_hash(&self, payment_hash: PaymentHash, min_value_msat: Option<u64>,
+		invoice_expiry_delta_secs: u32, min_final_cltv_expiry: Option<u16>) -> Result<PaymentSecret, ()> {
+		inbound_payment::create_from_hash(&self.inbound_payment_key, min_value_msat, payment_hash,
+			invoice_expiry_delta_secs, self.highest_seen_timestamp.load(Ordering::Acquire) as u64,
+			min_final_cltv_expiry)
 	}
 
 	/// Legacy version of [`create_inbound_payment_for_hash`]. Use this method if you wish to share
@@ -8505,7 +8529,7 @@ pub mod bench {
 				payment_preimage.0[0..8].copy_from_slice(&payment_count.to_le_bytes());
 				payment_count += 1;
 				let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0[..]).into_inner());
-				let payment_secret = $node_b.create_inbound_payment_for_hash(payment_hash, None, 7200).unwrap();
+				let payment_secret = $node_b.create_inbound_payment_for_hash(payment_hash, None, 7200, None).unwrap();
 
 				$node_a.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
 				let payment_event = SendEvent::from_event($node_a.get_and_clear_pending_msg_events().pop().unwrap());

lightning/src/ln/functional_test_utils.rs

@@ -1447,17 +1447,22 @@ macro_rules! get_payment_preimage_hash {
 		}
 	};
 	($dest_node: expr, $min_value_msat: expr) => {
+		{
+			crate::get_payment_preimage_hash!($dest_node, $min_value_msat, None)
+		}
+	};
+	($dest_node: expr, $min_value_msat: expr, $min_final_cltv_expiry_delta: expr) => {
 		{
 			use bitcoin::hashes::Hash as _;
 			let mut payment_count = $dest_node.network_payment_count.borrow_mut();
 			let payment_preimage = $crate::ln::PaymentPreimage([*payment_count; 32]);
 			*payment_count += 1;
 			let payment_hash = $crate::ln::PaymentHash(
 				bitcoin::hashes::sha256::Hash::hash(&payment_preimage.0[..]).into_inner());
-			let payment_secret = $dest_node.node.create_inbound_payment_for_hash(payment_hash, $min_value_msat, 7200).unwrap();
+			let payment_secret = $dest_node.node.create_inbound_payment_for_hash(payment_hash, $min_value_msat, 7200, $min_final_cltv_expiry_delta).unwrap();
 			(payment_preimage, payment_hash, payment_secret)
 		}
-	}
+	};
 }
 
 #[macro_export]

lightning/src/ln/functional_tests.rs

@@ -1246,7 +1246,7 @@ fn test_duplicate_htlc_different_direction_onchain() {
 	let (payment_preimage, payment_hash, _) = route_payment(&nodes[0], &vec!(&nodes[1])[..], 900_000);
 
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[1], nodes[0], 800_000);
-	let node_a_payment_secret = nodes[0].node.create_inbound_payment_for_hash(payment_hash, None, 7200).unwrap();
+	let node_a_payment_secret = nodes[0].node.create_inbound_payment_for_hash(payment_hash, None, 7200, None).unwrap();
 	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[0]]], 800_000, payment_hash, node_a_payment_secret);
 
 	// Provide preimage to node 0 by claiming payment
@@ -4712,7 +4712,7 @@ fn test_duplicate_payment_hash_one_failure_one_success() {
 
 	let (our_payment_preimage, duplicate_payment_hash, _) = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 900_000);
 
-	let payment_secret = nodes[3].node.create_inbound_payment_for_hash(duplicate_payment_hash, None, 7200).unwrap();
+	let payment_secret = nodes[3].node.create_inbound_payment_for_hash(duplicate_payment_hash, None, 7200, None).unwrap();
 	// We reduce the final CLTV here by a somewhat arbitrary constant to keep it under the one-byte
 	// script push size limit so that the below script length checks match
 	// ACCEPTED_HTLC_SCRIPT_WEIGHT.
@@ -4925,30 +4925,30 @@ fn do_test_fail_backwards_unrevoked_remote_announce(deliver_last_raa: bool, anno
 	let (_, payment_hash_2, _) = route_payment(&nodes[0], &[&nodes[2], &nodes[3], &nodes[4]], ds_dust_limit*1000); // not added < dust limit + HTLC tx fee
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[1], nodes[5], ds_dust_limit*1000);
 	// 2nd HTLC:
-	send_along_route_with_secret(&nodes[1], route.clone(), &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_1, nodes[5].node.create_inbound_payment_for_hash(payment_hash_1, None, 7200).unwrap()); // not added < dust limit + HTLC tx fee
+	send_along_route_with_secret(&nodes[1], route.clone(), &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_1, nodes[5].node.create_inbound_payment_for_hash(payment_hash_1, None, 7200, None).unwrap()); // not added < dust limit + HTLC tx fee
 	// 3rd HTLC:
-	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_2, nodes[5].node.create_inbound_payment_for_hash(payment_hash_2, None, 7200).unwrap()); // not added < dust limit + HTLC tx fee
+	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_2, nodes[5].node.create_inbound_payment_for_hash(payment_hash_2, None, 7200, None).unwrap()); // not added < dust limit + HTLC tx fee
 	// 4th HTLC:
 	let (_, payment_hash_3, _) = route_payment(&nodes[0], &[&nodes[2], &nodes[3], &nodes[4]], 1000000);
 	// 5th HTLC:
 	let (_, payment_hash_4, _) = route_payment(&nodes[0], &[&nodes[2], &nodes[3], &nodes[4]], 1000000);
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[1], nodes[5], 1000000);
 	// 6th HTLC:
-	send_along_route_with_secret(&nodes[1], route.clone(), &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_3, nodes[5].node.create_inbound_payment_for_hash(payment_hash_3, None, 7200).unwrap());
+	send_along_route_with_secret(&nodes[1], route.clone(), &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_3, nodes[5].node.create_inbound_payment_for_hash(payment_hash_3, None, 7200, None).unwrap());
 	// 7th HTLC:
-	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_4, nodes[5].node.create_inbound_payment_for_hash(payment_hash_4, None, 7200).unwrap());
+	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_4, nodes[5].node.create_inbound_payment_for_hash(payment_hash_4, None, 7200, None).unwrap());
 
 	// 8th HTLC:
 	let (_, payment_hash_5, _) = route_payment(&nodes[0], &[&nodes[2], &nodes[3], &nodes[4]], 1000000);
 	// 9th HTLC:
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[1], nodes[5], ds_dust_limit*1000);
-	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_5, nodes[5].node.create_inbound_payment_for_hash(payment_hash_5, None, 7200).unwrap()); // not added < dust limit + HTLC tx fee
+	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], ds_dust_limit*1000, payment_hash_5, nodes[5].node.create_inbound_payment_for_hash(payment_hash_5, None, 7200, None).unwrap()); // not added < dust limit + HTLC tx fee
 
 	// 10th HTLC:
 	let (_, payment_hash_6, _) = route_payment(&nodes[0], &[&nodes[2], &nodes[3], &nodes[4]], ds_dust_limit*1000); // not added < dust limit + HTLC tx fee
 	// 11th HTLC:
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[1], nodes[5], 1000000);
-	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_6, nodes[5].node.create_inbound_payment_for_hash(payment_hash_6, None, 7200).unwrap());
+	send_along_route_with_secret(&nodes[1], route, &[&[&nodes[2], &nodes[3], &nodes[5]]], 1000000, payment_hash_6, nodes[5].node.create_inbound_payment_for_hash(payment_hash_6, None, 7200, None).unwrap());
 
 	// Double-check that six of the new HTLC were added
 	// We now have six HTLCs pending over the dust limit and six HTLCs under the dust limit (ie,
@@ -6922,7 +6922,7 @@ fn test_check_htlc_underpaying() {
 	let payment_params = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id()).with_features(nodes[1].node.invoice_features());
 	let route = get_route(&nodes[0].node.get_our_node_id(), &payment_params, &nodes[0].network_graph.read_only(), None, 10_000, TEST_FINAL_CLTV, nodes[0].logger, &scorer, &random_seed_bytes).unwrap();
 	let (_, our_payment_hash, _) = get_payment_preimage_hash!(nodes[0]);
-	let our_payment_secret = nodes[1].node.create_inbound_payment_for_hash(our_payment_hash, Some(100_000), 7200).unwrap();
+	let our_payment_secret = nodes[1].node.create_inbound_payment_for_hash(our_payment_hash, Some(100_000), 7200, None).unwrap();
 	nodes[0].node.send_payment(&route, our_payment_hash, &Some(our_payment_secret), PaymentId(our_payment_hash.0)).unwrap();
 	check_added_monitors!(nodes[0], 1);
 
@@ -7917,7 +7917,7 @@ fn test_preimage_storage() {
 	create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
 
 	{
-		let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment(Some(100_000), 7200).unwrap();
+		let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment(Some(100_000), 7200, None).unwrap();
 		let (route, _, _, _) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);
 		nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
 		check_added_monitors!(nodes[0], 1);
@@ -8023,7 +8023,7 @@ fn test_bad_secret_hash() {
 
 	let random_payment_hash = PaymentHash([42; 32]);
 	let random_payment_secret = PaymentSecret([43; 32]);
-	let (our_payment_hash, our_payment_secret) = nodes[1].node.create_inbound_payment(Some(100_000), 2).unwrap();
+	let (our_payment_hash, our_payment_secret) = nodes[1].node.create_inbound_payment(Some(100_000), 2, None).unwrap();
 	let (route, _, _, _) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);
 
 	// All the below cases should end up being handled exactly identically, so we macro the
@@ -9582,3 +9582,60 @@ fn accept_busted_but_better_fee() {
 		_ => panic!("Unexpected event"),
 	};
 }
+
+fn do_payment_with_custom_min_final_cltv_expiry(valid_delta: bool, use_user_hash: bool) {
+	let mut chanmon_cfgs = create_chanmon_cfgs(2);
+	let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+	let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+	let min_final_cltv_expiry_delta = 120;
+	let final_cltv_expiry_delta = if valid_delta { min_final_cltv_expiry_delta + 2 } else {
+		min_final_cltv_expiry_delta - 2 };
+	let recv_value = 100_000;
+
+	create_chan_between_nodes(&nodes[0], &nodes[1]);
+
+	let payment_parameters = PaymentParameters::from_node_id(nodes[1].node.get_our_node_id());
+	let (payment_hash, payment_preimage, payment_secret) = if use_user_hash {
+		let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[1],
+			Some(recv_value), Some(min_final_cltv_expiry_delta));
+		(payment_hash, payment_preimage, payment_secret)
+	} else {
+		let (payment_hash, payment_secret) = nodes[1].node.create_inbound_payment(Some(recv_value), 7200, Some(min_final_cltv_expiry_delta)).unwrap();
+		(payment_hash, nodes[1].node.get_payment_preimage(payment_hash, payment_secret).unwrap(), payment_secret)
+	};
+	let route = get_route!(nodes[0], payment_parameters, recv_value, final_cltv_expiry_delta as u32).unwrap();
+	nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), PaymentId(payment_hash.0)).unwrap();
+	check_added_monitors!(nodes[0], 1);
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 1);
+	let mut payment_event = SendEvent::from_event(events.pop().unwrap());
+	nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+	commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false);
+	expect_pending_htlcs_forwardable!(nodes[1]);
+
+	if valid_delta {
+		expect_payment_claimable!(nodes[1], payment_hash, payment_secret, recv_value, if use_user_hash {
+			None } else { Some(payment_preimage) }, nodes[1].node.get_our_node_id());
+
+		claim_payment(&nodes[0], &vec!(&nodes[1])[..], payment_preimage);
+	} else {
+		expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash }]);
+
+		check_added_monitors!(nodes[1], 1);
+
+		let fail_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+		nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &fail_updates.update_fail_htlcs[0]);
+		commitment_signed_dance!(nodes[0], nodes[1], fail_updates.commitment_signed, false, true);
+
+		expect_payment_failed!(nodes[0], payment_hash, true);
+	}
+}
+
+#[test]
+fn test_payment_with_custom_min_cltv_expiry_delta() {
+	do_payment_with_custom_min_final_cltv_expiry(false, false);
+	do_payment_with_custom_min_final_cltv_expiry(false, true);
+	do_payment_with_custom_min_final_cltv_expiry(true, false);
+	do_payment_with_custom_min_final_cltv_expiry(true, true);
+}