Function decode_onion

tests/plugins/channeld_fakenet.c:305–361

Sets current_node, *next_onion_packet, *shared_secret and *me, and decodes */

/* Sets current_node, *next_onion_packet, *shared_secret and *me, and decodes */
static struct onion_payload *decode_onion(const tal_t *ctx,
					  struct info *info,
					  const u8 onion_routing_packet[],
					  const struct pubkey *path_key,
					  const struct sha256 *payment_hash,
					  struct amount_msat amount,
					  u32 cltv,
					  u8 **next_onion_packet,
					  struct secret *shared_secret,
					  struct gossmap_node **me)
{
	struct onionpacket *op;
	enum onion_wire failcode;
	struct route_step *rs = NULL;
	struct onion_payload *payload;
	u64 failtlvtype;
	size_t failtlvpos;
	const char *explanation;

	op = parse_onionpacket(tmpctx, onion_routing_packet,
			       TOTAL_PACKET_SIZE(ROUTING_INFO_SIZE),
			       &failcode);
	if (!op)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Could not parse onion (failcode %u)", failcode);

	if (!ecdh_maybe_blinding(&op->ephemeralkey, path_key, shared_secret))
		abort();
	rs = process_onionpacket(tmpctx, op, shared_secret,
				 payment_hash->u.u8, sizeof(*payment_hash));
	if (!rs)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Could not decode onion for %s", current_node->name);
	*next_onion_packet = get_next_onion(ctx, rs);

	payload = onion_decode(tmpctx,
			       rs, path_key,
			       NULL,
			       amount,
			       cltv, &failtlvtype, &failtlvpos, &explanation);
	if (!payload) {
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Failed tlvtype %"PRIu64" at %zu: %s",
			      failtlvtype, failtlvpos, explanation);
	}

	/* Find ourselves in the gossmap, so we know our channels */
	*me = gossmap_find_node(info->gossmap, &current_node->id);
	if (!*me)
		status_failed(STATUS_FAIL_INTERNAL_ERROR,
			      "Cannot find %s (%s) in gossmap",
			      current_node->name,
			      fmt_node_id(tmpctx, &current_node->id));

	status_debug("Unpacked onion for %s", current_node->name);
	return payload;
}