Function fill_from_update

common/gossmap.c:525–568

Does not set hc->nodeidx! * Returns false if it doesn't fit in our representation: this happens * on the real network, as people set absurd fees */

 * on the real network, as people set absurd fees
 */
static bool fill_from_update(struct gossmap *map,
			     struct short_channel_id_dir *scidd,
			     struct half_chan *hc,
			     u64 cupdate_off)
{
	/* Note that first two bytes are message type */
	const u64 scid_off = cupdate_off + 2 + (64 + 32);
	const u64 message_flags_off = scid_off + 8 + 4;
	const u64 channel_flags_off = message_flags_off + 1;
	const u64 cltv_expiry_delta_off = channel_flags_off + 1;
	const u64 htlc_minimum_off = cltv_expiry_delta_off + 2;
	const u64 fee_base_off = htlc_minimum_off + 8;
	const u64 fee_prop_off = fee_base_off + 4;
	const u64 htlc_maximum_off = fee_prop_off + 4;
	u8 chanflags;
	u32 base_fee, proportional_fee;
	u16 delay;

	/* We round this *down*, since too-low min is more conservative */
	hc->htlc_min = u64_to_fp16(map_be64(map, htlc_minimum_off), false);
	hc->htlc_max = u64_to_fp16(map_be64(map, htlc_maximum_off), true);

	scidd->scid.u64 = map_be64(map, scid_off);
	chanflags = map_u8(map, channel_flags_off);
	scidd->dir = (chanflags & ROUTING_FLAGS_DIRECTION);
	hc->enabled = !(chanflags & ROUTING_FLAGS_DISABLED);
	base_fee = map_be32(map, fee_base_off);
	proportional_fee = map_be32(map, fee_prop_off);
	delay = map_be16(map, cltv_expiry_delta_off);

	hc->base_fee = base_fee;
	hc->proportional_fee = proportional_fee;
	hc->delay = delay;

	/* Check they fit: we turn off if not. */
	if (hc->base_fee != base_fee
	    || hc->proportional_fee != proportional_fee
	    || hc->delay != delay) {
		hc->htlc_max = 0;
		hc->enabled = false;
		return false;
	}
	return true;
}

/* BOLT #7:
 * 1. type: 258 (`channel_update`)