struct dns_msg*
dns_cache_lookup(struct module_env* env,
uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
uint16_t flags, struct regional* region, struct regional* scratch,
int no_partial)
{
struct lruhash_entry* e;
struct query_info k;
hashvalue_type h;
time_t now = *env->now;
struct ub_packed_rrset_key* rrset;
/* lookup first, this has both NXdomains and ANSWER responses */
k.qname = qname;
k.qname_len = qnamelen;
k.qtype = qtype;
k.qclass = qclass;
k.local_alias = NULL;
h = query_info_hash(&k, flags);
e = slabhash_lookup(env->msg_cache, h, &k, 0);
if(e) {
struct msgreply_entry* key = (struct msgreply_entry*)e->key;
struct reply_info* data = (struct reply_info*)e->data;
struct dns_msg* msg = tomsg(env, &key->key, data, region, now,
scratch);
if(msg) {
lock_rw_unlock(&e->lock);
return msg;
}
/* could be msg==NULL; due to TTL or not all rrsets available */
lock_rw_unlock(&e->lock);
}
/* see if a DNAME exists. Checked for first, to enforce that DNAMEs
* are more important, the CNAME is resynthesized and thus
* consistent with the DNAME */
if(!no_partial &&
(rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
LDNS_RR_TYPE_DNAME, 1))) {
/* 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,
&sec_status);
if(msg) {
struct ub_packed_rrset_key* cname_rrset;
lock_rw_unlock(&rrset->entry.lock);
/* now, after unlocking the DNAME rrset lock,
* check the sec_status, and see if we need to look
* up the CNAME record associated before it can
* be used */
/* normally, only secure DNAMEs allowed from cache*/
if(sec_status == sec_status_secure)
return msg;
/* but if we have a CNAME cached with this name, then we
* have previously already allowed this name to pass.
* the next cache lookup is going to fetch that CNAME itself,
* but it is better to have the (unsigned)DNAME + CNAME in
* that case */
cname_rrset = rrset_cache_lookup(
env->rrset_cache, qname, qnamelen,
LDNS_RR_TYPE_CNAME, qclass, 0, now, 0);
if(cname_rrset) {
/* CNAME already synthesized by
* synth_dname_msg routine, so we can
* straight up return the msg */
lock_rw_unlock(&cname_rrset->entry.lock);
return msg;
}
} else {
lock_rw_unlock(&rrset->entry.lock);
}
}
/* see if we have CNAME for this domain,
* but not for DS records (which are part of the parent) */
if(!no_partial && qtype != LDNS_RR_TYPE_DS &&
(rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
uint8_t* wc = NULL;
size_t wl;
/* if the rrset is not a wildcard expansion, with wcname */
/* because, if we return that CNAME rrset on its own, it is
* missing the NSEC or NSEC3 proof */
if(!(val_rrset_wildcard(rrset, &wc, &wl) && wc != NULL)) {
struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
if(msg) {
lock_rw_unlock(&rrset->entry.lock);
return msg;
}
}
lock_rw_unlock(&rrset->entry.lock);
}
/* construct DS, DNSKEY, DLV messages from rrset cache. */
if((qtype == LDNS_RR_TYPE_DS || qtype == LDNS_RR_TYPE_DNSKEY ||
qtype == LDNS_RR_TYPE_DLV) &&
(rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
qtype, qclass, 0, now, 0))) {
/* if the rrset is from the additional section, and the
* signatures have fallen off, then do not synthesize a msg
* instead, allow a full query for signed results to happen.
* Forego all rrset data from additional section, because
* some signatures may not be present and cause validation
* failure.
*/
struct packed_rrset_data *d = (struct packed_rrset_data*)
rrset->entry.data;
if(d->trust != rrset_trust_add_noAA &&
d->trust != rrset_trust_add_AA &&
(qtype == LDNS_RR_TYPE_DS ||
(d->trust != rrset_trust_auth_noAA
&& d->trust != rrset_trust_auth_AA) )) {
struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
if(msg) {
lock_rw_unlock(&rrset->entry.lock);
return msg;
}
}
lock_rw_unlock(&rrset->entry.lock);
}
/* stop downwards cache search on NXDOMAIN.
* Empty nonterminals are NOERROR, so an NXDOMAIN for foo
* means bla.foo also does not exist. The DNSSEC proofs are
* the same. We search upwards for NXDOMAINs. */
if(env->cfg->harden_below_nxdomain)
while(!dname_is_root(k.qname)) {
dname_remove_label(&k.qname, &k.qname_len);
h = query_info_hash(&k, flags);
e = slabhash_lookup(env->msg_cache, h, &k, 0);
if(!e && k.qtype != LDNS_RR_TYPE_A &&
env->cfg->qname_minimisation) {
k.qtype = LDNS_RR_TYPE_A;
h = query_info_hash(&k, flags);
e = slabhash_lookup(env->msg_cache, h, &k, 0);
}
if(e) {
struct reply_info* data = (struct reply_info*)e->data;
struct dns_msg* msg;
if(FLAGS_GET_RCODE(data->flags) == LDNS_RCODE_NXDOMAIN
&& data->security == sec_status_secure
&& (msg=tomsg(env, &k, data, region, now, scratch))){
lock_rw_unlock(&e->lock);
msg->qinfo.qname=qname;
msg->qinfo.qname_len=qnamelen;
/* check that DNSSEC really works out */
msg->rep->security = sec_status_unchecked;
return msg;
}
lock_rw_unlock(&e->lock);
}
k.qtype = qtype;
}
/* fill common RR types for ANY response to avoid requery */
if(qtype == LDNS_RR_TYPE_ANY) {
return fill_any(env, qname, qnamelen, qtype, qclass, region);
}
return NULL;
}
struct dns_msg*
dns_cache_lookup(struct module_env* env,
uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
uint16_t flags, struct regional* region, struct regional* scratch)
{
struct lruhash_entry* e;
struct query_info k;
hashvalue_t h;
time_t now = *env->now;
struct ub_packed_rrset_key* rrset;
/* lookup first, this has both NXdomains and ANSWER responses */
k.qname = qname;
k.qname_len = qnamelen;
k.qtype = qtype;
k.qclass = qclass;
h = query_info_hash(&k, flags);
e = slabhash_lookup(env->msg_cache, h, &k, 0);
if(e) {
struct msgreply_entry* key = (struct msgreply_entry*)e->key;
struct reply_info* data = (struct reply_info*)e->data;
struct dns_msg* msg = tomsg(env, &key->key, data, region, now,
scratch);
if(msg) {
lock_rw_unlock(&e->lock);
return msg;
}
/* could be msg==NULL; due to TTL or not all rrsets available */
lock_rw_unlock(&e->lock);
}
/* see if a DNAME exists. Checked for first, to enforce that DNAMEs
* are more important, the CNAME is resynthesized and thus
* consistent with the DNAME */
if( (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
LDNS_RR_TYPE_DNAME, 1))) {
/* synthesize a DNAME+CNAME message based on this */
struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k);
if(msg) {
lock_rw_unlock(&rrset->entry.lock);
return msg;
}
lock_rw_unlock(&rrset->entry.lock);
}
/* see if we have CNAME for this domain,
* but not for DS records (which are part of the parent) */
if( qtype != LDNS_RR_TYPE_DS &&
(rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
if(msg) {
lock_rw_unlock(&rrset->entry.lock);
return msg;
}
lock_rw_unlock(&rrset->entry.lock);
}
/* construct DS, DNSKEY, DLV messages from rrset cache. */
if((qtype == LDNS_RR_TYPE_DS || qtype == LDNS_RR_TYPE_DNSKEY ||
qtype == LDNS_RR_TYPE_DLV) &&
(rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen,
qtype, qclass, 0, now, 0))) {
/* if the rrset is from the additional section, and the
* signatures have fallen off, then do not synthesize a msg
* instead, allow a full query for signed results to happen.
* Forego all rrset data from additional section, because
* some signatures may not be present and cause validation
* failure.
*/
struct packed_rrset_data *d = (struct packed_rrset_data*)
rrset->entry.data;
if(d->trust != rrset_trust_add_noAA &&
d->trust != rrset_trust_add_AA &&
(qtype == LDNS_RR_TYPE_DS ||
(d->trust != rrset_trust_auth_noAA
&& d->trust != rrset_trust_auth_AA) )) {
struct dns_msg* msg = rrset_msg(rrset, region, now, &k);
if(msg) {
lock_rw_unlock(&rrset->entry.lock);
return msg;
}
}
lock_rw_unlock(&rrset->entry.lock);
}
/* stop downwards cache search on NXDOMAIN.
* Empty nonterminals are NOERROR, so an NXDOMAIN for foo
* means bla.foo also does not exist. The DNSSEC proofs are
* the same. We search upwards for NXDOMAINs. */
if(env->cfg->harden_below_nxdomain)
while(!dname_is_root(k.qname)) {
dname_remove_label(&k.qname, &k.qname_len);
h = query_info_hash(&k, flags);
e = slabhash_lookup(env->msg_cache, h, &k, 0);
if(e) {
struct reply_info* data = (struct reply_info*)e->data;
struct dns_msg* msg;
if(FLAGS_GET_RCODE(data->flags) == LDNS_RCODE_NXDOMAIN
&& data->security == sec_status_secure
&& (msg=tomsg(env, &k, data, region, now, scratch))) {
lock_rw_unlock(&e->lock);
msg->qinfo.qname=qname;
msg->qinfo.qname_len=qnamelen;
/* check that DNSSEC really works out */
msg->rep->security = sec_status_unchecked;
return msg;
}
lock_rw_unlock(&e->lock);
}
}
return NULL;
}
