Function feerate_max

lightningd/chaintopology.c:1212–1248

}

u32 feerate_max(struct lightningd *ld, bool *unknown)
{
	const struct chain_topology *topo = ld->topology;
	u32 max = 0;
	u64 scaled;

	if (unknown)
		*unknown = false;

	for (size_t i = 0; i < ARRAY_SIZE(topo->feerates); i++) {
		const size_t num_feerates = tal_count(topo->feerates[i]);
		for (size_t j = 0; j < num_feerates; j++) {
			if (topo->feerates[i][j].rate > max)
				max = topo->feerates[i][j].rate;
		}
	}
	if (!max) {
		if (unknown)
			*unknown = true;
		/* No estimates: fall back to the ceiling, exactly as
		 * feerate_min falls back to the floor.  Returning UINT_MAX
		 * here would be a sentinel meaning "no bound at all", and
		 * that bound is what a peer's proposal gets measured
		 * against and what we then store: a value that large
		 * overflows the 25/24 RBF calculation. */
		return FEERATE_CEILING;
	}
	/* Estimates are clamped to FEERATE_CEILING on the way in, but the
	 * multiplier is settable, so widen before multiplying. */
	scaled = (u64)max * topo->ld->config.max_fee_multiplier;

	/* Don't let the multiplier carry us past the sanity ceiling: above
	 * that a peer is not congested, their fee source is broken. */
	if (scaled > FEERATE_CEILING)
		return FEERATE_CEILING;
	return scaled;
}

u32 our_feerate_max(struct lightningd *ld, bool *unknown)
{