Function peer_failed_our_htlc

lightningd/peer_htlcs.c:1455–1526

}

static bool peer_failed_our_htlc(struct channel *channel,
				 const struct failed_htlc *failed)
{
	struct htlc_out *hout;
	struct lightningd *ld = channel->peer->ld;

	hout = find_htlc_out(&ld->htlcs_out, channel, failed->id);
	if (!hout) {
		channel_internal_error(channel,
				    "failed_our_htlc unknown htlc %"PRIu64,
				    failed->id);
		return false;
	}

	if (!htlc_out_update_state(channel, hout, RCVD_REMOVE_COMMIT))
		return false;

	if (failed->sha256_of_onion) {
		struct sha256 our_sha256_of_onion;
		u8 *failmsg;

		/* BOLT #2:
		 *
		 *   - if the `sha256_of_onion` in `update_fail_malformed_htlc`
		 *     doesn't match the onion it sent:
		 *    - MAY retry or choose an alternate error response.
		 */
		sha256(&our_sha256_of_onion, hout->onion_routing_packet,
		       sizeof(hout->onion_routing_packet));
		if (!sha256_eq(failed->sha256_of_onion, &our_sha256_of_onion))
			log_unusual(channel->log,
				    "update_fail_malformed_htlc for bad onion"
				       " for htlc with id %"PRIu64".",
				    hout->key.id);

		/* BOLT #2:
		 *
		 * - otherwise, a receiving node which has an outgoing HTLC
		 *   canceled by `update_fail_malformed_htlc`:
		 *
		 * - MUST return an error in the `update_fail_htlc`
		 *   sent to the link which originally sent the HTLC, using the
		 *   `failure_code` given and setting the data to
		 *   `sha256_of_onion`.
		 */
		/* All badonion codes are the same form, so we make them
		 * manually, which covers any unknown cases too.  Grep fodder:
		 * towire_invalid_onion_version, towire_invalid_onion_hmac,
		 * towire_invalid_onion_key. */
		failmsg = tal_arr(hout, u8, 0);
		towire_u16(&failmsg, failed->badonion);
		towire_sha256(&failmsg, failed->sha256_of_onion);
		hout->failmsg = failmsg;
	} else {
		hout->failonion = dup_onionreply(hout, failed->onion);
	}

	log_debug(channel->log, "Our HTLC %"PRIu64" failed (%u)", failed->id,