diff options
Diffstat (limited to 'services/cache')
| -rw-r--r-- | services/cache/dns.c | 111 | ||||
| -rw-r--r-- | services/cache/dns.h | 18 | ||||
| -rw-r--r-- | services/cache/infra.c | 6 |
3 files changed, 114 insertions, 21 deletions
diff --git a/services/cache/dns.c b/services/cache/dns.c index f6c11451c93a..6bca8d85fadb 100644 --- a/services/cache/dns.c +++ b/services/cache/dns.c @@ -68,11 +68,16 @@ * in a prefetch situation to be updated (without becoming sticky). * @param qrep: update rrsets here if cache is better * @param region: for qrep allocs. + * @param qstarttime: time when delegations were looked up, this is perhaps + * earlier than the time in now. The time is used to determine if RRsets + * of type NS have expired, so that they can only be updated using + * lookups of delegation points that did not use them, since they had + * expired then. */ static void store_rrsets(struct module_env* env, struct reply_info* rep, time_t now, time_t leeway, int pside, struct reply_info* qrep, - struct regional* region) + struct regional* region, time_t qstarttime) { size_t i; /* see if rrset already exists in cache, if not insert it. */ @@ -81,8 +86,8 @@ store_rrsets(struct module_env* env, struct reply_info* rep, time_t now, rep->ref[i].id = rep->rrsets[i]->id; /* update ref if it was in the cache */ switch(rrset_cache_update(env->rrset_cache, &rep->ref[i], - env->alloc, now + ((ntohs(rep->ref[i].key->rk.type)== - LDNS_RR_TYPE_NS && !pside)?0:leeway))) { + env->alloc, ((ntohs(rep->ref[i].key->rk.type)== + LDNS_RR_TYPE_NS && !pside)?qstarttime:now + leeway))) { case 0: /* ref unchanged, item inserted */ break; case 2: /* ref updated, cache is superior */ @@ -155,7 +160,8 @@ msg_del_servfail(struct module_env* env, struct query_info* qinfo, 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, - struct reply_info* qrep, uint32_t flags, struct regional* region) + struct reply_info* qrep, uint32_t flags, struct regional* region, + time_t qstarttime) { struct msgreply_entry* e; time_t ttl = rep->ttl; @@ -170,7 +176,8 @@ dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, /* there was a reply_info_sortref(rep) here but it seems to be * unnecessary, because the cache gets locked per rrset. */ reply_info_set_ttls(rep, *env->now); - store_rrsets(env, rep, *env->now, leeway, pside, qrep, region); + store_rrsets(env, rep, *env->now, leeway, pside, qrep, region, + qstarttime); if(ttl == 0 && !(flags & DNSCACHE_STORE_ZEROTTL)) { /* we do not store the message, but we did store the RRs, * which could be useful for delegation information */ @@ -194,10 +201,51 @@ dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, slabhash_insert(env->msg_cache, hash, &e->entry, rep, env->alloc); } +/** see if an rrset is expired above the qname, return upper qname. */ +static int +rrset_expired_above(struct module_env* env, uint8_t** qname, size_t* qnamelen, + uint16_t searchtype, uint16_t qclass, time_t now, uint8_t* expiretop, + size_t expiretoplen) +{ + struct ub_packed_rrset_key *rrset; + uint8_t lablen; + + while(*qnamelen > 0) { + /* look one label higher */ + lablen = **qname; + *qname += lablen + 1; + *qnamelen -= lablen + 1; + if(*qnamelen <= 0) + break; + + /* looks up with a time of 0, to see expired entries */ + if((rrset = rrset_cache_lookup(env->rrset_cache, *qname, + *qnamelen, searchtype, qclass, 0, 0, 0))) { + struct packed_rrset_data* data = + (struct packed_rrset_data*)rrset->entry.data; + if(now > data->ttl) { + /* it is expired, this is not wanted */ + lock_rw_unlock(&rrset->entry.lock); + log_nametypeclass(VERB_ALGO, "this rrset is expired", *qname, searchtype, qclass); + return 1; + } + /* it is not expired, continue looking */ + lock_rw_unlock(&rrset->entry.lock); + } + + /* do not look above the expiretop. */ + if(expiretop && *qnamelen == expiretoplen && + query_dname_compare(*qname, expiretop)==0) + break; + } + return 0; +} + /** find closest NS or DNAME and returns the rrset (locked) */ static struct ub_packed_rrset_key* find_closest_of_type(struct module_env* env, uint8_t* qname, size_t qnamelen, - uint16_t qclass, time_t now, uint16_t searchtype, int stripfront) + uint16_t qclass, time_t now, uint16_t searchtype, int stripfront, + int noexpiredabove, uint8_t* expiretop, size_t expiretoplen) { struct ub_packed_rrset_key *rrset; uint8_t lablen; @@ -212,8 +260,40 @@ find_closest_of_type(struct module_env* env, uint8_t* qname, size_t qnamelen, /* snip off front part of qname until the type is found */ while(qnamelen > 0) { if((rrset = rrset_cache_lookup(env->rrset_cache, qname, - qnamelen, searchtype, qclass, 0, now, 0))) - return rrset; + qnamelen, searchtype, qclass, 0, now, 0))) { + uint8_t* origqname = qname; + size_t origqnamelen = qnamelen; + if(!noexpiredabove) + return rrset; + /* if expiretop set, do not look above it, but + * qname is equal, so the just found result is also + * the nonexpired above part. */ + if(expiretop && qnamelen == expiretoplen && + query_dname_compare(qname, expiretop)==0) + return rrset; + /* check for expiry, but we have to let go of the rrset + * for the lock ordering */ + lock_rw_unlock(&rrset->entry.lock); + /* the expired_above function always takes off one + * label (if qnamelen>0) and returns the final qname + * where it searched, so we can continue from there + * turning the O N*N search into O N. */ + if(!rrset_expired_above(env, &qname, &qnamelen, + searchtype, qclass, now, expiretop, + expiretoplen)) { + /* we want to return rrset, but it may be + * gone from cache, if so, just loop like + * it was not in the cache in the first place. + */ + if((rrset = rrset_cache_lookup(env-> + rrset_cache, origqname, origqnamelen, + searchtype, qclass, 0, now, 0))) { + return rrset; + } + } + log_nametypeclass(VERB_ALGO, "ignoring rrset because expired rrsets exist above it", origqname, searchtype, qclass); + continue; + } /* snip off front label */ lablen = *qname; @@ -462,7 +542,8 @@ dns_msg_ansadd(struct dns_msg* msg, struct regional* region, struct delegpt* dns_cache_find_delegation(struct module_env* env, uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, - struct regional* region, struct dns_msg** msg, time_t now) + struct regional* region, struct dns_msg** msg, time_t now, + int noexpiredabove, uint8_t* expiretop, size_t expiretoplen) { /* try to find closest NS rrset */ struct ub_packed_rrset_key* nskey; @@ -470,7 +551,7 @@ dns_cache_find_delegation(struct module_env* env, uint8_t* qname, struct delegpt* dp; nskey = find_closest_of_type(env, qname, qnamelen, qclass, now, - LDNS_RR_TYPE_NS, 0); + LDNS_RR_TYPE_NS, 0, noexpiredabove, expiretop, expiretoplen); if(!nskey) /* hope the caller has hints to prime or something */ return NULL; nsdata = (struct packed_rrset_data*)nskey->entry.data; @@ -840,7 +921,7 @@ dns_cache_lookup(struct module_env* env, * consistent with the DNAME */ if(!no_partial && (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now, - LDNS_RR_TYPE_DNAME, 1))) { + LDNS_RR_TYPE_DNAME, 1, 0, NULL, 0))) { /* synthesize a DNAME+CNAME message based on this */ enum sec_status sec_status = sec_status_unchecked; struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k, @@ -973,7 +1054,7 @@ 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 regional* region, uint32_t flags) + struct regional* region, uint32_t flags, time_t qstarttime) { struct reply_info* rep = NULL; /* alloc, malloc properly (not in region, like msg is) */ @@ -996,9 +1077,9 @@ dns_cache_store(struct module_env* env, struct query_info* msgqinf, /*ignore ret: it was in the cache, ref updated */ /* no leeway for typeNS */ (void)rrset_cache_update(env->rrset_cache, &ref, - env->alloc, *env->now + + env->alloc, ((ntohs(ref.key->rk.type)==LDNS_RR_TYPE_NS - && !pside) ? 0:leeway)); + && !pside) ? qstarttime:*env->now + leeway)); } free(rep); return 1; @@ -1020,7 +1101,7 @@ dns_cache_store(struct module_env* env, struct query_info* msgqinf, rep->flags &= ~(BIT_AA | BIT_CD); h = query_info_hash(&qinf, (uint16_t)flags); dns_cache_store_msg(env, &qinf, h, rep, leeway, pside, msgrep, - flags, region); + flags, region, qstarttime); /* qname is used inside query_info_entrysetup, and set to * NULL. If it has not been used, free it. free(0) is safe. */ free(qinf.qname); diff --git a/services/cache/dns.h b/services/cache/dns.h index bece83702960..147f992cbc74 100644 --- a/services/cache/dns.h +++ b/services/cache/dns.h @@ -88,11 +88,13 @@ struct dns_msg { * @param flags: flags with BIT_CD for AAAA queries in dns64 translation. * The higher 16 bits are used internally to customize the cache policy. * (See DNSCACHE_STORE_xxx flags). + * @param qstarttime: time when the query was started, and thus when the + * delegations were looked up. * @return 0 on alloc error (out of memory). */ int dns_cache_store(struct module_env* env, struct query_info* qinf, struct reply_info* rep, int is_referral, time_t leeway, int pside, - struct regional* region, uint32_t flags); + struct regional* region, uint32_t flags, time_t qstarttime); /** * Store message in the cache. Stores in message cache and rrset cache. @@ -112,11 +114,14 @@ int dns_cache_store(struct module_env* env, struct query_info* qinf, * can be updated to full TTL even in prefetch situations. * @param qrep: message that can be altered with better rrs from cache. * @param flags: customization flags for the cache policy. + * @param qstarttime: time when the query was started, and thus when the + * delegations were looked up. * @param region: to allocate into for qmsg. */ 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, - struct reply_info* qrep, uint32_t flags, struct regional* region); + struct reply_info* qrep, uint32_t flags, struct regional* region, + time_t qstarttime); /** * Find a delegation from the cache. @@ -129,11 +134,18 @@ void dns_cache_store_msg(struct module_env* env, struct query_info* qinfo, * @param msg: if not NULL, delegation message is returned here, synthesized * from the cache. * @param timenow: the time now, for checking if TTL on cache entries is OK. + * @param noexpiredabove: if set, no expired NS rrsets above the one found + * are tolerated. It only returns delegations where the delegations above + * it are valid. + * @param expiretop: if not NULL, name where check for expiry ends for + * noexpiredabove. + * @param expiretoplen: length of expiretop dname. * @return new delegation or NULL on error or if not found in cache. */ struct delegpt* dns_cache_find_delegation(struct module_env* env, uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, - struct regional* region, struct dns_msg** msg, time_t timenow); + struct regional* region, struct dns_msg** msg, time_t timenow, + int noexpiredabove, uint8_t* expiretop, size_t expiretoplen); /** * generate dns_msg from cached message diff --git a/services/cache/infra.c b/services/cache/infra.c index 252e1e288b35..0461c815b86b 100644 --- a/services/cache/infra.c +++ b/services/cache/infra.c @@ -721,13 +721,13 @@ infra_get_lame_rtt(struct infra_cache* infra, else *rtt = USEFUL_SERVER_TOP_TIMEOUT-1000; } } + /* expired entry */ if(timenow > host->ttl) { - /* expired entry */ + /* see if this can be a re-probe of an unresponsive server */ /* minus 1000 because that is outside of the RTTBAND, so * blacklisted servers stay blacklisted if this is chosen */ - if(host->rtt.rto >= USEFUL_SERVER_TOP_TIMEOUT || - infra->infra_keep_probing) { + if(host->rtt.rto >= USEFUL_SERVER_TOP_TIMEOUT) { lock_rw_unlock(&e->lock); *rtt = USEFUL_SERVER_TOP_TIMEOUT-1000; *lame = 0; |