Function channel_update_for_error

lightningd/channel.c:1335–1352

BOLT #4: * An _intermediate hop_ MUST NOT, but the _final node_: *... * - if it returns a `channel_update`: * - MUST set `short_channel_id` to the `short_channel_id` used * by the incoming onion. */ So, if the scid doesn't match (redirect or we chose an equivalent * channel), we simply don't return an update. */

/* So, if the scid doesn't match (redirect or we chose an equivalent
 * channel), we simply don't return an update. */
const u8 *channel_update_for_error(const tal_t *ctx,
				   const struct htlc_in *hin,
				   struct channel *channel)
{
	if (!hin || !hin->payload || !hin->payload->forward_channel)
		return NULL;

	/* We shouldn't have forwarded to the channel if it wasn't
	 * allowed to use that scid, so we can keep it simple here. */
	if ((!channel->alias[LOCAL]
	     || !short_channel_id_eq(*hin->payload->forward_channel, *channel->alias[LOCAL]))
	    && (!channel->scid
		|| !short_channel_id_eq(*hin->payload->forward_channel, *channel->scid))) {
		return NULL;
	}

	return channel_gossip_update_for_error(ctx, channel);
}