+/// Intended destination of a failed HTLC as indicated in [`Event::HTLCHandlingFailed`].
+#[derive(Clone, Debug, PartialEq)]
+pub enum HTLCDestination {
+ /// We tried forwarding to a channel but failed to do so. An example of such an instance is when
+ /// there is insufficient capacity in our outbound channel.
+ NextHopChannel {
+ /// The `node_id` of the next node. For backwards compatibility, this field is
+ /// marked as optional, versions prior to 0.0.110 may not always be able to provide
+ /// counterparty node information.
+ node_id: Option<PublicKey>,
+ /// The outgoing `channel_id` between us and the next node.
+ channel_id: [u8; 32],
+ },
+ /// Scenario where we are unsure of the next node to forward the HTLC to.
+ UnknownNextHop {
+ /// Short channel id we are requesting to forward an HTLC to.
+ requested_forward_scid: u64,
+ },
+ /// Failure scenario where an HTLC may have been forwarded to be intended for us,
+ /// but is invalid for some reason, so we reject it.
+ ///
+ /// Some of the reasons may include:
+ /// * HTLC Timeouts
+ /// * Expected MPP amount to claim does not equal HTLC total
+ /// * Claimable amount does not match expected amount
+ FailedPayment {
+ /// The payment hash of the payment we attempted to process.
+ payment_hash: PaymentHash
+ },
+}
+
+impl_writeable_tlv_based_enum_upgradable!(HTLCDestination,
+ (0, NextHopChannel) => {
+ (0, node_id, required),
+ (2, channel_id, required),
+ },
+ (2, UnknownNextHop) => {
+ (0, requested_forward_scid, required),
+ },
+ (4, FailedPayment) => {
+ (0, payment_hash, required),
+ }
+);
+