/** synthesize RRset-only response from cached RRset item */
static struct dns_msg*
rrset_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
time_t now, struct query_info* q)
{
struct dns_msg* msg;
struct packed_rrset_data* d = (struct packed_rrset_data*)
rrset->entry.data;
if(now > d->ttl)
return NULL;
msg = gen_dns_msg(region, q, 1); /* only the CNAME (or other) RRset */
if(!msg)
return NULL;
msg->rep->flags = BIT_QR; /* reply, no AA, no error */
msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
msg->rep->qdcount = 1;
msg->rep->ttl = d->ttl - now;
msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
msg->rep->security = sec_status_unchecked;
msg->rep->an_numrrsets = 1;
msg->rep->ns_numrrsets = 0;
msg->rep->ar_numrrsets = 0;
msg->rep->rrset_count = 1;
msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
if(!msg->rep->rrsets[0]) /* copy CNAME */
return NULL;
return msg;
}
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;
}
/** synthesize DNAME+CNAME response from cached DNAME item */
static struct dns_msg*
synth_dname_msg(struct ub_packed_rrset_key* rrset, struct regional* region,
time_t now, struct query_info* q, enum sec_status* sec_status)
{
struct dns_msg* msg;
struct ub_packed_rrset_key* ck;
struct packed_rrset_data* newd, *d = (struct packed_rrset_data*)
rrset->entry.data;
uint8_t* newname, *dtarg = NULL;
size_t newlen, dtarglen;
if(now > d->ttl)
return NULL;
/* only allow validated (with DNSSEC) DNAMEs used from cache
* for insecure DNAMEs, query again. */
*sec_status = d->security;
/* return sec status, so the status of the CNAME can be checked
* by the calling routine. */
msg = gen_dns_msg(region, q, 2); /* DNAME + CNAME RRset */
if(!msg)
return NULL;
msg->rep->flags = BIT_QR; /* reply, no AA, no error */
msg->rep->authoritative = 0; /* reply stored in cache can't be authoritative */
msg->rep->qdcount = 1;
msg->rep->ttl = d->ttl - now;
msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
msg->rep->security = sec_status_unchecked;
msg->rep->an_numrrsets = 1;
msg->rep->ns_numrrsets = 0;
msg->rep->ar_numrrsets = 0;
msg->rep->rrset_count = 1;
msg->rep->rrsets[0] = packed_rrset_copy_region(rrset, region, now);
if(!msg->rep->rrsets[0]) /* copy DNAME */
return NULL;
/* synth CNAME rrset */
get_cname_target(rrset, &dtarg, &dtarglen);
if(!dtarg)
return NULL;
newlen = q->qname_len + dtarglen - rrset->rk.dname_len;
if(newlen > LDNS_MAX_DOMAINLEN) {
msg->rep->flags |= LDNS_RCODE_YXDOMAIN;
return msg;
}
newname = (uint8_t*)regional_alloc(region, newlen);
if(!newname)
return NULL;
/* new name is concatenation of qname front (without DNAME owner)
* and DNAME target name */
memcpy(newname, q->qname, q->qname_len-rrset->rk.dname_len);
memmove(newname+(q->qname_len-rrset->rk.dname_len), dtarg, dtarglen);
/* create rest of CNAME rrset */
ck = (struct ub_packed_rrset_key*)regional_alloc(region,
sizeof(struct ub_packed_rrset_key));
if(!ck)
return NULL;
memset(&ck->entry, 0, sizeof(ck->entry));
msg->rep->rrsets[1] = ck;
ck->entry.key = ck;
ck->rk.type = htons(LDNS_RR_TYPE_CNAME);
ck->rk.rrset_class = rrset->rk.rrset_class;
ck->rk.flags = 0;
ck->rk.dname = regional_alloc_init(region, q->qname, q->qname_len);
if(!ck->rk.dname)
return NULL;
ck->rk.dname_len = q->qname_len;
ck->entry.hash = rrset_key_hash(&ck->rk);
newd = (struct packed_rrset_data*)regional_alloc_zero(region,
sizeof(struct packed_rrset_data) + sizeof(size_t) +
sizeof(uint8_t*) + sizeof(time_t) + sizeof(uint16_t)
+ newlen);
if(!newd)
return NULL;
ck->entry.data = newd;
newd->ttl = 0; /* 0 for synthesized CNAME TTL */
newd->count = 1;
newd->rrsig_count = 0;
newd->trust = rrset_trust_ans_noAA;
newd->rr_len = (size_t*)((uint8_t*)newd +
sizeof(struct packed_rrset_data));
newd->rr_len[0] = newlen + sizeof(uint16_t);
packed_rrset_ptr_fixup(newd);
newd->rr_ttl[0] = newd->ttl;
msg->rep->ttl = newd->ttl;
msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(newd->ttl);
sldns_write_uint16(newd->rr_data[0], newlen);
memmove(newd->rr_data[0] + sizeof(uint16_t), newname, newlen);
msg->rep->an_numrrsets ++;
msg->rep->rrset_count ++;
return msg;
}