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 {
@@ -367,7 +368,7 @@ 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

@@ -974,7 +974,7 @@ impl OutboundPayments {
 
 					if let Err(()) = onion_utils::set_max_path_length(
 						&mut route_params, &RecipientOnionFields::spontaneous_empty(), Some(keysend_preimage),
-						best_block_height
+						invoice_request.as_ref(), best_block_height
 					) {
 						abandon_with_entry!(entry, PaymentFailureReason::UnexpectedError);
 						return Err(Bolt12PaymentError::SendingFailed(RetryableSendFailure::OnionPacketSizeExceeded))
@@ -1122,7 +1122,7 @@ 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

@@ -641,8 +641,9 @@ 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
 		)
 	}
 }