diff options
Diffstat (limited to 'services/cache/dns.c')
| -rw-r--r-- | services/cache/dns.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/services/cache/dns.c b/services/cache/dns.c index 411793c6c270..35adc35b57ee 100644 --- a/services/cache/dns.c +++ b/services/cache/dns.c @@ -108,6 +108,48 @@ store_rrsets(struct module_env* env, struct reply_info* rep, time_t now, } } +/** delete message from message cache */ +static void +msg_cache_remove(struct module_env* env, uint8_t* qname, size_t qnamelen, + uint16_t qtype, uint16_t qclass, uint16_t flags) +{ + struct query_info k; + hashvalue_type h; + + k.qname = qname; + k.qname_len = qnamelen; + k.qtype = qtype; + k.qclass = qclass; + k.local_alias = NULL; + h = query_info_hash(&k, flags); + slabhash_remove(env->msg_cache, h, &k); +} + +/** remove servfail msg cache entry */ +static void +msg_del_servfail(struct module_env* env, struct query_info* qinfo, + uint32_t flags) +{ + struct msgreply_entry* e; + /* see if the entry is servfail, and then remove it, so that + * lookups move from the cacheresponse stage to the recursionresponse + * stage */ + e = msg_cache_lookup(env, qinfo->qname, qinfo->qname_len, + qinfo->qtype, qinfo->qclass, flags, 0, 0); + if(!e) return; + /* we don't check for the ttl here, also expired servfail entries + * are removed. If the user uses serve-expired, they would still be + * used to answer from cache */ + if(FLAGS_GET_RCODE(((struct reply_info*)e->entry.data)->flags) + != LDNS_RCODE_SERVFAIL) { + lock_rw_unlock(&e->entry.lock); + return; + } + lock_rw_unlock(&e->entry.lock); + msg_cache_remove(env, qinfo->qname, qinfo->qname_len, qinfo->qtype, + qinfo->qclass, flags); +} + void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, hashvalue_type hash, struct reply_info* rep, time_t leeway, int pside, @@ -132,6 +174,12 @@ dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, * which could be useful for delegation information */ verbose(VERB_ALGO, "TTL 0: dropped msg from cache"); free(rep); + /* if the message is SERVFAIL in cache, remove that SERVFAIL, + * so that the TTL 0 response can be returned for future + * responses (i.e. don't get answered by the servfail from + * cache, but instead go to recursion to get this TTL0 + * response). */ + msg_del_servfail(env, qinfo, flags); return; } |