- Add suggestion to refresh the cached norec_ttl and expired_ttl when a

  response cannot update the usable expired entry.

diff --git a/services/cache/dns.c b/services/cache/dns.c
index 5a6036f8675faa7e2e64193b565a7f4df9ee5905..351b3568c80b71f9ef130b6344b1463fa16c4b9b 100644 (file)
--- a/services/cache/dns.c
+++ b/services/cache/dns.c
@@ -1056,7 +1056,7 @@ dns_cache_lookup(struct module_env* env,
 
 int
 dns_cache_store(struct module_env* env, struct query_info* msgqinf,
-        struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
+       struct reply_info* msgrep, int is_referral, time_t leeway, int pside,
        struct regional* region, uint32_t flags, time_t qstarttime,
        int is_valrec)
 {
@@ -1066,7 +1066,7 @@ dns_cache_store(struct module_env* env, struct query_info* msgqinf,
                 * useful expired record exists. */
                struct msgreply_entry* e = msg_cache_lookup(env,
                        msgqinf->qname, msgqinf->qname_len, msgqinf->qtype,
-                       msgqinf->qclass, flags, 0, 0);
+                       msgqinf->qclass, flags, 0, 1);
                if(e) {
                        struct reply_info* cached = e->entry.data;
                        if(cached->ttl < *env->now
@@ -1090,6 +1090,33 @@ dns_cache_store(struct module_env* env, struct query_info* msgqinf,
                                 *   validated. */
                                && !is_valrec
                                && msgqinf->qtype != LDNS_RR_TYPE_RRSIG) {
+                               if((int)FLAGS_GET_RCODE(msgrep->flags) !=
+                                       LDNS_RCODE_NOERROR &&
+                                       (int)FLAGS_GET_RCODE(msgrep->flags) !=
+                                       LDNS_RCODE_NXDOMAIN) {
+                                       /* The current response has an
+                                        * erroneous rcode. Adjust norec time
+                                        * so that additional lookups are not
+                                        * performed for some time. */
+                                       verbose(VERB_ALGO, "set "
+                                               "serve-expired-norec-ttl for "
+                                               "response in cache");
+                                       cached->serve_expired_norec_ttl =
+                                               NORR_TTL + *env->now;
+                                       if(env->cfg->serve_expired_ttl_reset &&
+                                           cached->serve_expired_ttl
+                                           < *env->now +
+                                           env->cfg->serve_expired_ttl) {
+                                               /* Reset serve-expired-ttl for
+                                                * valid response in cache. */
+                                               verbose(VERB_ALGO, "reset "
+                                                       "serve-expired-ttl "
+                                                       "for response in cache");
+                                               cached->serve_expired_ttl =
+                                                   *env->now +
+                                                   env->cfg->serve_expired_ttl;
+                                       }
+                               }
                                verbose(VERB_ALGO, "a validated expired entry "
                                        "could be overwritten, skip caching "
                                        "the new message at this stage");