DS push: use DNSKEY TTL for parent DS

src/knot/events/handlers/ds_push.c

@@ -171,6 +171,7 @@ static int send_ds_push(conf_t *conf, zone_t *zone,
 		return KNOT_EOK; // No CDS, do nothing.
 	}
 	zone_cds.type = KNOT_RRTYPE_DS;
+	zone_cds.ttl = node_rrset(zone->contents->apex, KNOT_RRTYPE_DNSKEY).ttl;
 
 	struct ds_push_data data = {
 		.zone = zone->name,

tests-extra/tests/dnssec/ds_push/test.py

@@ -141,5 +141,7 @@ watch_ksk_rollover(t, child, child_zone, 2, 2, 3, "KSK rollover")
 
 resp = parent.dig(ZONE, "DS")
 resp.check_count(1, rtype="DS")
+if resp.resp.answer[0].ttl != child.dnssec(child_zone).dnskey_ttl:
+    set_err("DS TTL")
 
 t.end()