Function create_onion

plugins/renepay/routetracker.c:304–356

}

static const u8 *create_onion(
    const tal_t *ctx, const unsigned int blockheight,
    const struct route_hop *route, const struct sha256 *payment_hash,
    const u32 final_cltv_delta, const struct blinded_path *blinded_path,
    const struct secret *payment_secret, const struct amount_msat total_amount,
    const struct amount_msat deliver_amount, const u8 *metadata,
    const struct node_id first_node, const size_t first_index,
    struct secret **shared_secrets)
{
	bool ret;
	const tal_t *this_ctx = tal(ctx, tal_t);
	struct node_id current_node = first_node;
	struct pubkey node;
	const u8 *payload;
	const size_t pathlen = tal_count(route);

	struct sphinx_path *sp = sphinx_path_new(this_ctx, payment_hash->u.u8,
						 sizeof(payment_hash->u.u8));

	for (size_t i = first_index; i < pathlen; i++) {
		/* Encrypted message is for node[i] but the data is hop[i+1],
		 * therein lays the problem with sendpay's API. */
		ret = pubkey_from_node_id(&node, &current_node);
		assert(ret);

		const struct route_hop *hop = &route[i];
		payload = onion_nonfinal_hop(this_ctx, &hop->scid, hop->amount,
					     hop->delay + blockheight);
		// FIXME: better handle error here
		ret = sphinx_add_hop_has_length(sp, &node, take(payload));
		assert(ret);
		current_node = route[i].node_id;
	}

	const u32 final_cltv = final_cltv_delta + blockheight;
	if (blinded_path) {
		sphinx_append_blinded_path(this_ctx, sp, blinded_path,
					   deliver_amount, total_amount,
					   final_cltv);
	} else {
		sphinx_append_final_hop(this_ctx, sp, payment_secret,
					&current_node, deliver_amount,
					total_amount, final_cltv, metadata);
	}

	struct onionpacket *packet =
	    create_onionpacket(this_ctx, sp, ROUTING_INFO_SIZE, shared_secrets);
	*shared_secrets = tal_steal(ctx, *shared_secrets);

	const u8 *onion = serialize_onionpacket(ctx, packet);
	tal_free(this_ctx);
	return onion;
}

static u32 initial_cltv_delta(const struct route *route,
			      const struct payment_info *pinfo)