Function source_free_layer

plugins/askrene/askrene.c:225–258

If we're the payer, we don't add delay or fee to our own outgoing * channels. This wouldn't be right if we looped back through ourselves, * but we won't. */ FIXME: We could cache this until gossmap/layer changes... */

 * but we won't. */
/* FIXME: We could cache this until gossmap/layer changes... */
static struct layer *source_free_layer(const tal_t *ctx,
				       struct askrene *askrene,
				       const struct node_id *source,
				       struct gossmap_localmods *localmods)
{
	/* We apply existing localmods so we see *all* channels */
	struct gossmap *gossmap = askrene->gossmap;
	const struct gossmap_node *srcnode;
	const struct amount_msat zero_base_fee = AMOUNT_MSAT(0);
	const u16 zero_delay = 0;
	const u32 zero_prop_fee = 0;
	struct layer *layer = new_temp_layer(ctx, askrene, "auto.sourcefree");

	/* We apply this so we see any created channels */
	gossmap_apply_localmods(gossmap, localmods);

	/* If we're not in map, we complain later */
	srcnode = gossmap_find_node(gossmap, source);

	for (size_t i = 0; srcnode && i < srcnode->num_chans; i++) {
		struct short_channel_id_dir scidd;
		const struct gossmap_chan *c;

		c = gossmap_nth_chan(gossmap, srcnode, i, &scidd.dir);
		scidd.scid = gossmap_chan_scid(gossmap, c);
		layer_add_update_channel(layer, &scidd,
					 NULL, NULL, NULL,
					 &zero_base_fee, &zero_prop_fee,
					 &zero_delay);
	}
	gossmap_remove_localmods(gossmap, localmods);

	return layer;
}

/* We're going to abuse MCF, and take the largest flow it gives and ram everything
 * through it.  This is more effective if there's at least a *chance* that can handle