lib/cache: properly cache meta types and RRSIG queries

lib/layer/pktcache.c

@@ -173,10 +173,11 @@ static int stash(knot_layer_t *ctx, knot_pkt_t *pkt)
 	if (!knot_wire_get_aa(pkt->wire) || knot_pkt_qclass(pkt) != KNOT_CLASS_IN) {
 		return ctx->state;
 	}
-	const bool is_any = knot_pkt_qtype(pkt) == KNOT_RRTYPE_ANY;
+	/* Cache only NODATA/NXDOMAIN or metatype/RRSIG answers. */
+	const uint16_t qtype = knot_pkt_qtype(pkt);
+	const bool is_eligible = (knot_rrtype_is_metatype(qtype) || qtype == KNOT_RRTYPE_RRSIG);
 	int pkt_class = kr_response_classify(pkt);
-	/* Cache only NODATA/NXDOMAIN or ANY answers. */
-	if (!((pkt_class & (PKT_NODATA|PKT_NXDOMAIN)) || is_any)) {
+	if (!(is_eligible || (pkt_class & (PKT_NODATA|PKT_NXDOMAIN)))) {
 		return ctx->state;
 	}
 	uint32_t ttl = packet_ttl(pkt);
@@ -190,7 +191,6 @@ static int stash(knot_layer_t *ctx, knot_pkt_t *pkt)
 		return ctx->state; /* Couldn't acquire cache, ignore. */
 	}
 	const knot_dname_t *qname = knot_pkt_qname(pkt);
-	uint16_t qtype = knot_pkt_qtype(pkt);
 	namedb_val_t data = { pkt->wire, pkt->size };
 	struct kr_cache_entry header = {
 		.timestamp = qry->timestamp.tv_sec,

lib/layer/rrcache.c

@@ -282,9 +282,14 @@ static int stash(knot_layer_t *ctx, knot_pkt_t *pkt)
 	if (!qry || ctx->state & KNOT_STATE_FAIL) {
 		return ctx->state;
 	}
-
-	/* Cache only positive answers. */
-	if (qry->flags & QUERY_CACHED || knot_wire_get_rcode(pkt->wire) != KNOT_RCODE_NOERROR) {
+	/* Do not cache truncated answers. */
+	if (knot_wire_get_tc(pkt->wire)) {
+		return ctx->state;
+	}
+	/* Cache only positive answers, not meta types or RRSIG. */
+	const uint16_t qtype = knot_pkt_qtype(pkt);
+	const bool is_eligible = !(knot_rrtype_is_metatype(qtype) || qtype == KNOT_RRTYPE_RRSIG);
+	if (qry->flags & QUERY_CACHED || knot_wire_get_rcode(pkt->wire) != KNOT_RCODE_NOERROR || !is_eligible) {
 		return ctx->state;
 	}
 	/* Stash in-bailiwick data from the AUTHORITY and ANSWER. */
@@ -306,7 +311,7 @@ static int stash(knot_layer_t *ctx, knot_pkt_t *pkt)
 		stash_ds(qry, pkt, &stash, rplan->pool);
 	}
 	/* Cache stashed records */
-	if (ret == 0) {
+	if (ret == 0 && stash.root != NULL) {
 		/* Open write transaction */
 		struct kr_cache *cache = &req->ctx->cache;
 		struct kr_cache_txn txn;