Factor invreq into payment path len limiting.

Author: valentinewallace

lightning/src/ln/onion_utils.rs

@@ -320,7 +320,8 @@ pub(crate) const MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY: u64 = 100_000_000;
 
 pub(crate) fn set_max_path_length(
 	route_params: &mut RouteParameters, recipient_onion: &RecipientOnionFields,
-	keysend_preimage: Option<PaymentPreimage>, best_block_height: u32,
+	keysend_preimage: Option<PaymentPreimage>, invoice_request: Option<&InvoiceRequest>,
+	best_block_height: u32,
 ) -> Result<(), ()> {
 	const PAYLOAD_HMAC_LEN: usize = 32;
 	let unblinded_intermed_payload_len = msgs::OutboundOnionPayload::Forward {
@@ -368,7 +369,7 @@ pub(crate) fn set_max_path_length(
 		&recipient_onion,
 		best_block_height,
 		&keysend_preimage,
-		None,
+		invoice_request,
 		|_, payload| {
 			num_reserved_bytes = num_reserved_bytes
 				.saturating_add(payload.serialized_length())

lightning/src/ln/outbound_payment.rs

@@ -982,26 +982,29 @@ impl OutboundPayments {
 		IH: Fn() -> InFlightHtlcs,
 		SP: Fn(SendAlongPathArgs) -> Result<(), APIError>,
 	{
-		let (payment_hash, keysend_preimage, mut route_params) =
+		let (payment_hash, route_params) =
 			match self.pending_outbound_payments.lock().unwrap().entry(payment_id) {
-				hash_map::Entry::Occupied(entry) => match entry.get() {
+				hash_map::Entry::Occupied(mut entry) => match entry.get_mut() {
 					PendingOutboundPayment::StaticInvoiceReceived {
-						payment_hash, payment_release_secret: release_secret, keysend_preimage, route_params, ..
+						payment_hash, payment_release_secret: release_secret, keysend_preimage, invoice_request,
+						route_params, ..
 					} => {
 						if payment_release_secret != *release_secret {
 							return Err(Bolt12PaymentError::UnexpectedInvoice)
 						}
-						(*payment_hash, *keysend_preimage, route_params.clone())
+
+						onion_utils::set_max_path_length(
+							route_params, &RecipientOnionFields::spontaneous_empty(),
+							Some(*keysend_preimage), Some(invoice_request), best_block_height
+						).map_err(|()| Bolt12PaymentError::SendingFailed(RetryableSendFailure::OnionPacketSizeExceeded))?;
+
+						(*payment_hash, route_params.clone())
 					},
 					_ => return Err(Bolt12PaymentError::DuplicateInvoice),
 				},
 				hash_map::Entry::Vacant(_) => return Err(Bolt12PaymentError::UnexpectedInvoice),
 			};
 
-		onion_utils::set_max_path_length(
-			&mut route_params, &RecipientOnionFields::spontaneous_empty(), Some(keysend_preimage), best_block_height
-		).map_err(|()| Bolt12PaymentError::SendingFailed(RetryableSendFailure::OnionPacketSizeExceeded))?;
-
 		self.find_route_and_send_payment(
 			payment_hash, payment_id, route_params, router, first_hops, &inflight_htlcs,
 			entropy_source, node_signer, best_block_height, logger, pending_events,
@@ -1096,7 +1099,7 @@ impl OutboundPayments {
 		}
 
 		onion_utils::set_max_path_length(
-			route_params, recipient_onion, keysend_preimage, best_block_height
+			route_params, recipient_onion, keysend_preimage, None, best_block_height
 		).map_err(|()| RetryableSendFailure::OnionPacketSizeExceeded)?;
 
 		let mut route = router.find_route_with_id(

lightning/src/routing/router.rs

@@ -643,8 +643,9 @@ impl RouteParameters {
 		&mut self, recipient_onion: &RecipientOnionFields, is_keysend: bool, best_block_height: u32
 	) -> Result<(), ()> {
 		let keysend_preimage_opt = is_keysend.then(|| PaymentPreimage([42; 32]));
+		// TODO: no way to account for the invoice request here yet
 		onion_utils::set_max_path_length(
-			self, recipient_onion, keysend_preimage_opt, best_block_height
+			self, recipient_onion, keysend_preimage_opt, None, best_block_height
 		)
 	}
 }