struct dns_msg*
tomsg(struct module_env* env, struct query_info* q, struct reply_info* r,
struct regional* region, time_t now, struct regional* scratch)
{
struct dns_msg* msg;
size_t i;
if(now > r->ttl)
return NULL;
msg = gen_dns_msg(region, q, r->rrset_count);
if(!msg)
return NULL;
msg->rep->flags = r->flags;
msg->rep->qdcount = r->qdcount;
msg->rep->ttl = r->ttl - now;
if(r->prefetch_ttl > now)
msg->rep->prefetch_ttl = r->prefetch_ttl - now;
else msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
msg->rep->serve_expired_ttl = msg->rep->ttl + SERVE_EXPIRED_TTL;
msg->rep->security = r->security;
msg->rep->an_numrrsets = r->an_numrrsets;
msg->rep->ns_numrrsets = r->ns_numrrsets;
msg->rep->ar_numrrsets = r->ar_numrrsets;
msg->rep->rrset_count = r->rrset_count;
msg->rep->authoritative = r->authoritative;
if(!rrset_array_lock(r->ref, r->rrset_count, now))
return NULL;
if(r->an_numrrsets > 0 && (r->rrsets[0]->rk.type == htons(
LDNS_RR_TYPE_CNAME) || r->rrsets[0]->rk.type == htons(
LDNS_RR_TYPE_DNAME)) && !reply_check_cname_chain(q, r)) {
/* cname chain is now invalid, reconstruct msg */
rrset_array_unlock(r->ref, r->rrset_count);
return NULL;
}
if(r->security == sec_status_secure && !reply_all_rrsets_secure(r)) {
/* message rrsets have changed status, revalidate */
rrset_array_unlock(r->ref, r->rrset_count);
return NULL;
}
for(i=0; i<msg->rep->rrset_count; i++) {
msg->rep->rrsets[i] = packed_rrset_copy_region(r->rrsets[i],
region, now);
if(!msg->rep->rrsets[i]) {
rrset_array_unlock(r->ref, r->rrset_count);
return NULL;
}
}
if(env)
rrset_array_unlock_touch(env->rrset_cache, scratch, r->ref,
r->rrset_count);
else
rrset_array_unlock(r->ref, r->rrset_count);
return msg;
}
/** answer query from the cache */
static int
answer_from_cache(struct worker* worker, struct query_info* qinfo,
struct reply_info* rep, uint16_t id, uint16_t flags,
struct comm_reply* repinfo, struct edns_data* edns)
{
time_t timenow = *worker->env.now;
uint16_t udpsize = edns->udp_size;
int secure;
int must_validate = (!(flags&BIT_CD) || worker->env.cfg->ignore_cd)
&& worker->env.need_to_validate;
/* see if it is possible */
if(rep->ttl < timenow) {
/* the rrsets may have been updated in the meantime.
* we will refetch the message format from the
* authoritative server
*/
return 0;
}
if(!rrset_array_lock(rep->ref, rep->rrset_count, timenow))
return 0;
/* locked and ids and ttls are OK. */
/* check CNAME chain (if any) */
if(rep->an_numrrsets > 0 && (rep->rrsets[0]->rk.type ==
htons(LDNS_RR_TYPE_CNAME) || rep->rrsets[0]->rk.type ==
htons(LDNS_RR_TYPE_DNAME))) {
if(!reply_check_cname_chain(qinfo, rep)) {
/* cname chain invalid, redo iterator steps */
verbose(VERB_ALGO, "Cache reply: cname chain broken");
bail_out:
rrset_array_unlock_touch(worker->env.rrset_cache,
worker->scratchpad, rep->ref, rep->rrset_count);
return 0;
}
}
/* check security status of the cached answer */
if( rep->security == sec_status_bogus && must_validate) {
/* BAD cached */
edns->edns_version = EDNS_ADVERTISED_VERSION;
edns->udp_size = EDNS_ADVERTISED_SIZE;
edns->ext_rcode = 0;
edns->bits &= EDNS_DO;
if(!edns_opt_inplace_reply(edns, worker->scratchpad))
return 0;
error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
qinfo, id, flags, edns);
rrset_array_unlock_touch(worker->env.rrset_cache,
worker->scratchpad, rep->ref, rep->rrset_count);
if(worker->stats.extended) {
worker->stats.ans_bogus ++;
worker->stats.ans_rcode[LDNS_RCODE_SERVFAIL] ++;
}
return 1;
} else if( rep->security == sec_status_unchecked && must_validate) {
verbose(VERB_ALGO, "Cache reply: unchecked entry needs "
"validation");
goto bail_out; /* need to validate cache entry first */
} else if(rep->security == sec_status_secure) {
if(reply_all_rrsets_secure(rep))
secure = 1;
else {
if(must_validate) {
verbose(VERB_ALGO, "Cache reply: secure entry"
" changed status");
goto bail_out; /* rrset changed, re-verify */
}
secure = 0;
}
} else secure = 0;
edns->edns_version = EDNS_ADVERTISED_VERSION;
edns->udp_size = EDNS_ADVERTISED_SIZE;
edns->ext_rcode = 0;
edns->bits &= EDNS_DO;
if(!edns_opt_inplace_reply(edns, worker->scratchpad))
return 0;
if(!reply_info_answer_encode(qinfo, rep, id, flags,
repinfo->c->buffer, timenow, 1, worker->scratchpad,
udpsize, edns, (int)(edns->bits & EDNS_DO), secure)) {
error_encode(repinfo->c->buffer, LDNS_RCODE_SERVFAIL,
qinfo, id, flags, edns);
}
/* cannot send the reply right now, because blocking network syscall
* is bad while holding locks. */
rrset_array_unlock_touch(worker->env.rrset_cache, worker->scratchpad,
rep->ref, rep->rrset_count);
if(worker->stats.extended) {
if(secure) worker->stats.ans_secure++;
server_stats_insrcode(&worker->stats, repinfo->c->buffer);
}
/* go and return this buffer to the client */
return 1;
}
