Function path_to_node

plugins/fetchinvoice.c:589–641

Create path to node which can carry onion messages (including * self); if it can't find one, returns NULL. Fills in nodeid_parity * for 33rd nodeid byte. */

 * self); if it can't find one, returns NULL.  Fills in nodeid_parity
 * for 33rd nodeid byte. */
static struct pubkey *path_to_node(const tal_t *ctx,
				   struct plugin *plugin,
				   const struct point32 *node32_id,
				   enum nodeid_parity *parity)
{
	struct route_hop *r;
	const struct dijkstra *dij;
	const struct gossmap_node *src;
	const struct gossmap_node *dst;
	struct node_id dstid, local_nodeid;
	struct pubkey *nodes;
	struct gossmap *gossmap = get_gossmap(plugin);

	/* We try both parities. */
	*parity = nodeid_parity_even;
	node_id_from_point32(&dstid, node32_id, *parity);
	dst = gossmap_find_node(gossmap, &dstid);
	if (!dst) {
		*parity = nodeid_parity_odd;
		node_id_from_point32(&dstid, node32_id, *parity);
		dst = gossmap_find_node(gossmap, &dstid);
		if (!dst) {
			*parity = nodeid_parity_unknown;
			return NULL;
		}
	}

	*parity = node_parity(gossmap, dst);

	/* If we don't exist in gossip, routing can't happen. */
	node_id_from_pubkey(&local_nodeid, &local_id);
	src = gossmap_find_node(gossmap, &local_nodeid);
	if (!src)
		return NULL;

	dij = dijkstra(tmpctx, gossmap, dst, AMOUNT_MSAT(0), 0,
		       can_carry_onionmsg, route_score_shorter, NULL);

	r = route_from_dijkstra(tmpctx, gossmap, dij, src, AMOUNT_MSAT(0), 0);
	if (!r)
		return NULL;

	nodes = tal_arr(ctx, struct pubkey, tal_count(r) + 1);
	nodes[0] = local_id;
	for (size_t i = 0; i < tal_count(r); i++) {
		if (!pubkey_from_node_id(&nodes[i+1], &r[i].node_id)) {
			plugin_err(plugin, "Could not convert nodeid %s",
				   type_to_string(tmpctx, struct node_id,
						  &r[i].node_id));
		}
	}
	return nodes;
}

/* Marshal arguments for sending onion messages */
struct sending {