/** 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;
}
/**
* Copy and decompress rrs
* @param pkt: the packet for compression pointer resolution.
* @param msg: the parsed message
* @param rep: reply info to put rrs into.
* @param region: if not NULL, used for allocation.
* @return 0 on failure.
*/
static int
parse_copy_decompress(sldns_buffer* pkt, struct msg_parse* msg,
struct reply_info* rep, struct regional* region)
{
size_t i;
struct rrset_parse *pset = msg->rrset_first;
struct packed_rrset_data* data;
log_assert(rep);
rep->ttl = MAX_TTL;
rep->security = sec_status_unchecked;
if(rep->rrset_count == 0)
rep->ttl = NORR_TTL;
for(i=0; i<rep->rrset_count; i++) {
if(!parse_copy_decompress_rrset(pkt, msg, pset, region,
rep->rrsets[i]))
return 0;
data = (struct packed_rrset_data*)rep->rrsets[i]->entry.data;
if(data->ttl < rep->ttl)
rep->ttl = data->ttl;
pset = pset->rrset_all_next;
}
rep->prefetch_ttl = PREFETCH_TTL_CALC(rep->ttl);
return 1;
}
/** load a msg entry */
static int
load_msg(SSL* ssl, ldns_buffer* buf, struct worker* worker)
{
struct regional* region = worker->scratchpad;
struct query_info qinf;
struct reply_info rep;
char* s = (char*)ldns_buffer_begin(buf);
unsigned int flags, qdcount, ttl, security, an, ns, ar;
size_t i;
int go_on = 1;
regional_free_all(region);
if(strncmp(s, "msg ", 4) != 0) {
log_warn("error expected msg but got %s", s);
return 0;
}
s += 4;
s = load_qinfo(s, &qinf, buf, region);
if(!s) {
return 0;
}
/* read remainder of line */
if(sscanf(s, " %u %u %u %u %u %u %u", &flags, &qdcount, &ttl,
&security, &an, &ns, &ar) != 7) {
log_warn("error cannot parse numbers: %s", s);
return 0;
}
rep.flags = (uint16_t)flags;
rep.qdcount = (uint16_t)qdcount;
rep.ttl = (uint32_t)ttl;
rep.prefetch_ttl = PREFETCH_TTL_CALC(rep.ttl);
rep.security = (enum sec_status)security;
rep.an_numrrsets = (size_t)an;
rep.ns_numrrsets = (size_t)ns;
rep.ar_numrrsets = (size_t)ar;
rep.rrset_count = (size_t)an+(size_t)ns+(size_t)ar;
rep.rrsets = (struct ub_packed_rrset_key**)regional_alloc_zero(
region, sizeof(struct ub_packed_rrset_key*)*rep.rrset_count);
/* fill repinfo with references */
for(i=0; i<rep.rrset_count; i++) {
if(!load_ref(ssl, buf, worker, region, &rep.rrsets[i],
&go_on)) {
return 0;
}
}
if(!go_on)
return 1; /* skip this one, not all references satisfied */
if(!dns_cache_store(&worker->env, &qinf, &rep, 0, 0, 0, NULL)) {
log_warn("error out of memory");
return 0;
}
return 1;
}
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;
}
/* Adjust the TTL of a DNS message and its RRs by 'adjust'. If 'adjust' is
* negative, set the TTLs to 0. */
static void
adjust_msg_ttl(struct dns_msg* msg, time_t adjust)
{
size_t i;
if(adjust >= 0 && msg->rep->ttl > adjust)
msg->rep->ttl -= adjust;
else msg->rep->ttl = 0;
msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(msg->rep->ttl);
msg->rep->serve_expired_ttl = msg->rep->ttl + SERVE_EXPIRED_TTL;
for(i=0; i<msg->rep->rrset_count; i++) {
packed_rrset_ttl_subtract((struct packed_rrset_data*)msg->
rep->rrsets[i]->entry.data, adjust);
}
}
/** 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;
}