lib/pktcache: base ttl (fallback), cache IN only

diff --git a/lib/layer/pktcache.c b/lib/layer/pktcache.c
index fb627685cc07988ca87772cdfabbf1856dc1ebff..050aec156255e35320b7e1c11b12af6f0289cdd5 100644 (file)
--- a/lib/layer/pktcache.c
+++ b/lib/layer/pktcache.c
@@ -24,6 +24,7 @@
 
 #define DEBUG_MSG(fmt...) QRDEBUG(kr_rplan_current(rplan), " pc ",  fmt)
 #define DEFAULT_MAXTTL (15 * 60)
+#define DEFAULT_NOTTL (5) /* Short-time "no data" retention to avoid bursts */
 
 static inline uint8_t get_tag(knot_pkt_t *pkt)
 {
@@ -47,7 +48,9 @@ static void adjust_ttl(knot_rrset_t *rr, uint32_t drift)
        for (uint16_t i = 0; i < rr->rrs.rr_count; ++i) {
                knot_rdata_t *rd = knot_rdataset_at(&rr->rrs, i);
                uint32_t ttl = knot_rdata_ttl(rd);
-               knot_rdata_set_ttl(rd, ttl - drift);
+               if (ttl >= drift) {
+                       knot_rdata_set_ttl(rd, ttl - drift);
+               }
        }
 }
 
@@ -96,6 +99,9 @@ static int peek(knot_layer_t *ctx, knot_pkt_t *pkt)
        if (!qry || ctx->state & (KNOT_STATE_DONE|KNOT_STATE_FAIL)) {
                return ctx->state;
        }
+       if (knot_pkt_qclass(pkt) != KNOT_CLASS_IN) {
+               return ctx->state; /* Only IN class */
+       }
 
        /* Fetch packet from cache */
        namedb_txn_t txn;
@@ -119,7 +125,7 @@ static int peek(knot_layer_t *ctx, knot_pkt_t *pkt)
 
 static uint32_t packet_ttl(knot_pkt_t *pkt)
 {
-       uint32_t ttl = 0;
+       uint32_t ttl = DEFAULT_NOTTL;
        /* Fetch SOA from authority. */
        const knot_pktsection_t *ns = knot_pkt_section(pkt, KNOT_AUTHORITY);
        for (unsigned i = 0; i < ns->count; ++i) {
@@ -134,6 +140,10 @@ static uint32_t packet_ttl(knot_pkt_t *pkt)
                const knot_pktsection_t *sec = knot_pkt_section(pkt, i);
                for (unsigned k = 0; k < sec->count; ++k) {
                        const knot_rrset_t *rr = knot_pkt_rr(sec, k);
+                       /* Skip OPT and TSIG */
+                       if (rr->type == KNOT_RRTYPE_OPT || rr->type == KNOT_RRTYPE_TSIG) {
+                               continue;
+                       }
                        for (uint16_t i = 0; i < rr->rrs.rr_count; ++i) {
                                knot_rdata_t *rd = knot_rdataset_at(&rr->rrs, i);
                                if (knot_rdata_ttl(rd) < ttl) {
@@ -149,12 +159,16 @@ static int stash(knot_layer_t *ctx)
 {
        struct kr_request *req = ctx->data;
        struct kr_rplan *rplan = &req->rplan;
-       if (EMPTY_LIST(rplan->resolved) || ctx->state == KNOT_STATE_FAIL) {
+       if (EMPTY_LIST(rplan->resolved) || ctx->state & KNOT_STATE_FAIL) {
                return ctx->state; /* Don't cache anything if failed. */
        }
-       knot_pkt_t *pkt = req->answer;
        struct kr_query *qry = TAIL(rplan->resolved);
-       if (qry->flags & QUERY_CACHED || !(kr_response_classify(pkt) & (PKT_NODATA|PKT_NXDOMAIN))) {
+       knot_pkt_t *pkt = req->answer;
+       if (knot_pkt_qclass(pkt) != KNOT_CLASS_IN) {
+               return ctx->state; /* Only IN class */
+       }
+       int pkt_class = kr_response_classify(pkt);
+       if (qry->flags & QUERY_CACHED || !(pkt_class & (PKT_NODATA|PKT_NXDOMAIN))) {
                return ctx->state; /* Cache only negative, not-cached answers. */
        }
        uint32_t ttl = packet_ttl(pkt);