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monero/external/unbound/services/cache/dns.c

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/*
* services/cache/dns.c - Cache services for DNS using msg and rrset caches.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains the DNS cache.
*/
#include "config.h"
#include "iterator/iter_delegpt.h"
#include "validator/val_nsec.h"
#include "services/cache/dns.h"
#include "services/cache/rrset.h"
#include "util/data/msgreply.h"
#include "util/data/packed_rrset.h"
#include "util/data/dname.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/regional.h"
#include "util/config_file.h"
#include "sldns/sbuffer.h"
/** store rrsets in the rrset cache.
* @param env: module environment with caches.
* @param rep: contains list of rrsets to store.
* @param now: current time.
* @param leeway: during prefetch how much leeway to update TTLs.
* This makes rrsets (other than type NS) timeout sooner so they get
* updated with a new full TTL.
* Type NS does not get this, because it must not be refreshed from the
* child domain, but keep counting down properly.
* @param pside: if from parentside discovered NS, so that its NS is okay
* in a prefetch situation to be updated (without becoming sticky).
* @param qrep: update rrsets here if cache is better
* @param region: for qrep allocs.
*/
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)
{
size_t i;
/* see if rrset already exists in cache, if not insert it. */
for(i=0; i<rep->rrset_count; i++) {
rep->ref[i].key = rep->rrsets[i];
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))) {
case 0: /* ref unchanged, item inserted */
break;
case 2: /* ref updated, cache is superior */
if(region) {
struct ub_packed_rrset_key* ck;
lock_rw_rdlock(&rep->ref[i].key->entry.lock);
/* if deleted rrset, do not copy it */
if(rep->ref[i].key->id == 0)
ck = NULL;
else ck = packed_rrset_copy_region(
rep->ref[i].key, region, now);
lock_rw_unlock(&rep->ref[i].key->entry.lock);
if(ck) {
/* use cached copy if memory allows */
qrep->rrsets[i] = ck;
}
}
/* no break: also copy key item */
case 1: /* ref updated, item inserted */
rep->rrsets[i] = rep->ref[i].key;
}
}
}
void
dns_cache_store_msg(struct module_env* env, struct query_info* qinfo,
hashvalue_t hash, struct reply_info* rep, time_t leeway, int pside,
struct reply_info* qrep, struct regional* region)
{
struct msgreply_entry* e;
time_t ttl = rep->ttl;
size_t i;
/* store RRsets */
for(i=0; i<rep->rrset_count; i++) {
rep->ref[i].key = rep->rrsets[i];
rep->ref[i].id = rep->rrsets[i]->id;
}
/* 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);
if(ttl == 0) {
/* we do not store the message, but we did store the RRs,
* which could be useful for delegation information */
verbose(VERB_ALGO, "TTL 0: dropped msg from cache");
free(rep);
return;
}
/* store msg in the cache */
reply_info_sortref(rep);
if(!(e = query_info_entrysetup(qinfo, rep, hash))) {
log_err("store_msg: malloc failed");
return;
}
slabhash_insert(env->msg_cache, hash, &e->entry, rep, env->alloc);
}
/** 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)
{
struct ub_packed_rrset_key *rrset;
uint8_t lablen;
if(stripfront) {
/* strip off so that DNAMEs have strict subdomain match */
lablen = *qname;
qname += lablen + 1;
qnamelen -= lablen + 1;
}
/* 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;
/* snip off front label */
lablen = *qname;
qname += lablen + 1;
qnamelen -= lablen + 1;
}
return NULL;
}
/** add addr to additional section */
static void
addr_to_additional(struct ub_packed_rrset_key* rrset, struct regional* region,
struct dns_msg* msg, time_t now)
{
if((msg->rep->rrsets[msg->rep->rrset_count] =
packed_rrset_copy_region(rrset, region, now))) {
msg->rep->ar_numrrsets++;
msg->rep->rrset_count++;
}
}
/** lookup message in message cache */
static struct msgreply_entry*
msg_cache_lookup(struct module_env* env, uint8_t* qname, size_t qnamelen,
uint16_t qtype, uint16_t qclass, uint16_t flags, time_t now, int wr)
{
struct lruhash_entry* e;
struct query_info k;
hashvalue_t h;
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, wr);
if(!e) return NULL;
if( now > ((struct reply_info*)e->data)->ttl ) {
lock_rw_unlock(&e->lock);
return NULL;
}
return (struct msgreply_entry*)e->key;
}
/** find and add A and AAAA records for nameservers in delegpt */
static int
find_add_addrs(struct module_env* env, uint16_t qclass,
struct regional* region, struct delegpt* dp, time_t now,
struct dns_msg** msg)
{
struct delegpt_ns* ns;
struct msgreply_entry* neg;
struct ub_packed_rrset_key* akey;
for(ns = dp->nslist; ns; ns = ns->next) {
akey = rrset_cache_lookup(env->rrset_cache, ns->name,
ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
if(akey) {
if(!delegpt_add_rrset_A(dp, region, akey, 0)) {
lock_rw_unlock(&akey->entry.lock);
return 0;
}
if(msg)
addr_to_additional(akey, region, *msg, now);
lock_rw_unlock(&akey->entry.lock);
} else {
/* BIT_CD on false because delegpt lookup does
* not use dns64 translation */
neg = msg_cache_lookup(env, ns->name, ns->namelen,
LDNS_RR_TYPE_A, qclass, 0, now, 0);
if(neg) {
delegpt_add_neg_msg(dp, neg);
lock_rw_unlock(&neg->entry.lock);
}
}
akey = rrset_cache_lookup(env->rrset_cache, ns->name,
ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
if(akey) {
if(!delegpt_add_rrset_AAAA(dp, region, akey, 0)) {
lock_rw_unlock(&akey->entry.lock);
return 0;
}
if(msg)
addr_to_additional(akey, region, *msg, now);
lock_rw_unlock(&akey->entry.lock);
} else {
/* BIT_CD on false because delegpt lookup does
* not use dns64 translation */
neg = msg_cache_lookup(env, ns->name, ns->namelen,
LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
if(neg) {
delegpt_add_neg_msg(dp, neg);
lock_rw_unlock(&neg->entry.lock);
}
}
}
return 1;
}
/** find and add A and AAAA records for missing nameservers in delegpt */
int
cache_fill_missing(struct module_env* env, uint16_t qclass,
struct regional* region, struct delegpt* dp)
{
struct delegpt_ns* ns;
struct msgreply_entry* neg;
struct ub_packed_rrset_key* akey;
time_t now = *env->now;
for(ns = dp->nslist; ns; ns = ns->next) {
akey = rrset_cache_lookup(env->rrset_cache, ns->name,
ns->namelen, LDNS_RR_TYPE_A, qclass, 0, now, 0);
if(akey) {
if(!delegpt_add_rrset_A(dp, region, akey, ns->lame)) {
lock_rw_unlock(&akey->entry.lock);
return 0;
}
log_nametypeclass(VERB_ALGO, "found in cache",
ns->name, LDNS_RR_TYPE_A, qclass);
lock_rw_unlock(&akey->entry.lock);
} else {
/* BIT_CD on false because delegpt lookup does
* not use dns64 translation */
neg = msg_cache_lookup(env, ns->name, ns->namelen,
LDNS_RR_TYPE_A, qclass, 0, now, 0);
if(neg) {
delegpt_add_neg_msg(dp, neg);
lock_rw_unlock(&neg->entry.lock);
}
}
akey = rrset_cache_lookup(env->rrset_cache, ns->name,
ns->namelen, LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
if(akey) {
if(!delegpt_add_rrset_AAAA(dp, region, akey, ns->lame)) {
lock_rw_unlock(&akey->entry.lock);
return 0;
}
log_nametypeclass(VERB_ALGO, "found in cache",
ns->name, LDNS_RR_TYPE_AAAA, qclass);
lock_rw_unlock(&akey->entry.lock);
} else {
/* BIT_CD on false because delegpt lookup does
* not use dns64 translation */
neg = msg_cache_lookup(env, ns->name, ns->namelen,
LDNS_RR_TYPE_AAAA, qclass, 0, now, 0);
if(neg) {
delegpt_add_neg_msg(dp, neg);
lock_rw_unlock(&neg->entry.lock);
}
}
}
return 1;
}
/** find and add DS or NSEC to delegation msg */
static void
find_add_ds(struct module_env* env, struct regional* region,
struct dns_msg* msg, struct delegpt* dp, time_t now)
{
/* Lookup the DS or NSEC at the delegation point. */
struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
env->rrset_cache, dp->name, dp->namelen, LDNS_RR_TYPE_DS,
msg->qinfo.qclass, 0, now, 0);
if(!rrset) {
/* NOTE: this won't work for alternate NSEC schemes
* (opt-in, NSEC3) */
rrset = rrset_cache_lookup(env->rrset_cache, dp->name,
dp->namelen, LDNS_RR_TYPE_NSEC, msg->qinfo.qclass,
0, now, 0);
/* Note: the PACKED_RRSET_NSEC_AT_APEX flag is not used.
* since this is a referral, we need the NSEC at the parent
* side of the zone cut, not the NSEC at apex side. */
if(rrset && nsec_has_type(rrset, LDNS_RR_TYPE_DS)) {
lock_rw_unlock(&rrset->entry.lock);
rrset = NULL; /* discard wrong NSEC */
}
}
if(rrset) {
/* add it to auth section. This is the second rrset. */
if((msg->rep->rrsets[msg->rep->rrset_count] =
packed_rrset_copy_region(rrset, region, now))) {
msg->rep->ns_numrrsets++;
msg->rep->rrset_count++;
}
lock_rw_unlock(&rrset->entry.lock);
}
}
struct dns_msg*
dns_msg_create(uint8_t* qname, size_t qnamelen, uint16_t qtype,
uint16_t qclass, struct regional* region, size_t capacity)
{
struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
sizeof(struct dns_msg));
if(!msg)
return NULL;
msg->qinfo.qname = regional_alloc_init(region, qname, qnamelen);
if(!msg->qinfo.qname)
return NULL;
msg->qinfo.qname_len = qnamelen;
msg->qinfo.qtype = qtype;
msg->qinfo.qclass = qclass;
/* non-packed reply_info, because it needs to grow the array */
msg->rep = (struct reply_info*)regional_alloc_zero(region,
sizeof(struct reply_info)-sizeof(struct rrset_ref));
if(!msg->rep)
return NULL;
if(capacity > RR_COUNT_MAX)
return NULL; /* integer overflow protection */
msg->rep->flags = BIT_QR; /* with QR, no AA */
msg->rep->qdcount = 1;
msg->rep->rrsets = (struct ub_packed_rrset_key**)
regional_alloc(region,
capacity*sizeof(struct ub_packed_rrset_key*));
if(!msg->rep->rrsets)
return NULL;
return msg;
}
int
dns_msg_authadd(struct dns_msg* msg, struct regional* region,
struct ub_packed_rrset_key* rrset, time_t now)
{
if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
packed_rrset_copy_region(rrset, region, now)))
return 0;
msg->rep->ns_numrrsets++;
return 1;
}
/** add rrset to answer section */
static int
dns_msg_ansadd(struct dns_msg* msg, struct regional* region,
struct ub_packed_rrset_key* rrset, time_t now)
{
if(!(msg->rep->rrsets[msg->rep->rrset_count++] =
packed_rrset_copy_region(rrset, region, now)))
return 0;
msg->rep->an_numrrsets++;
return 1;
}
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)
{
/* try to find closest NS rrset */
struct ub_packed_rrset_key* nskey;
struct packed_rrset_data* nsdata;
struct delegpt* dp;
nskey = find_closest_of_type(env, qname, qnamelen, qclass, now,
LDNS_RR_TYPE_NS, 0);
if(!nskey) /* hope the caller has hints to prime or something */
return NULL;
nsdata = (struct packed_rrset_data*)nskey->entry.data;
/* got the NS key, create delegation point */
dp = delegpt_create(region);
if(!dp || !delegpt_set_name(dp, region, nskey->rk.dname)) {
lock_rw_unlock(&nskey->entry.lock);
log_err("find_delegation: out of memory");
return NULL;
}
/* create referral message */
if(msg) {
/* allocate the array to as much as we could need:
* NS rrset + DS/NSEC rrset +
* A rrset for every NS RR
* AAAA rrset for every NS RR
*/
*msg = dns_msg_create(qname, qnamelen, qtype, qclass, region,
2 + nsdata->count*2);
if(!*msg || !dns_msg_authadd(*msg, region, nskey, now)) {
lock_rw_unlock(&nskey->entry.lock);
log_err("find_delegation: out of memory");
return NULL;
}
}
if(!delegpt_rrset_add_ns(dp, region, nskey, 0))
log_err("find_delegation: addns out of memory");
lock_rw_unlock(&nskey->entry.lock); /* first unlock before next lookup*/
/* find and add DS/NSEC (if any) */
if(msg)
find_add_ds(env, region, *msg, dp, now);
/* find and add A entries */
if(!find_add_addrs(env, qclass, region, dp, now, msg))
log_err("find_delegation: addrs out of memory");
return dp;
}
/** allocate dns_msg from query_info and reply_info */
static struct dns_msg*
gen_dns_msg(struct regional* region, struct query_info* q, size_t num)
{
struct dns_msg* msg = (struct dns_msg*)regional_alloc(region,
sizeof(struct dns_msg));
if(!msg)
return NULL;
memcpy(&msg->qinfo, q, sizeof(struct query_info));
msg->qinfo.qname = regional_alloc_init(region, q->qname, q->qname_len);
if(!msg->qinfo.qname)
return NULL;
/* allocate replyinfo struct and rrset key array separately */
msg->rep = (struct reply_info*)regional_alloc(region,
sizeof(struct reply_info) - sizeof(struct rrset_ref));
if(!msg->rep)
return NULL;
if(num > RR_COUNT_MAX)
return NULL; /* integer overflow protection */
msg->rep->rrsets = (struct ub_packed_rrset_key**)
regional_alloc(region,
num * sizeof(struct ub_packed_rrset_key*));
if(!msg->rep->rrsets)
return NULL;
return msg;
}
/** generate dns_msg from cached message */
static 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->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;
}
}
rrset_array_unlock_touch(env->rrset_cache, scratch, r->ref,
r->rrset_count);
return msg;
}
/** 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;
}
/** 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)
{
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. */
if(d->security != sec_status_secure)
return NULL;
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;
}
/** Fill TYPE_ANY response with some data from cache */
static struct dns_msg*
fill_any(struct module_env* env,
uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
struct regional* region)
{
time_t now = *env->now;
struct dns_msg* msg = NULL;
uint16_t lookup[] = {LDNS_RR_TYPE_A, LDNS_RR_TYPE_AAAA,
LDNS_RR_TYPE_MX, LDNS_RR_TYPE_SOA, LDNS_RR_TYPE_NS,
LDNS_RR_TYPE_DNAME, 0};
int i, num=6; /* number of RR types to look up */
log_assert(lookup[num] == 0);
for(i=0; i<num; i++) {
/* look up this RR for inclusion in type ANY response */
struct ub_packed_rrset_key* rrset = rrset_cache_lookup(
env->rrset_cache, qname, qnamelen, lookup[i],
qclass, 0, now, 0);
struct packed_rrset_data *d;
if(!rrset)
continue;
/* only if rrset from answer section */
d = (struct packed_rrset_data*)rrset->entry.data;
if(d->trust == rrset_trust_add_noAA ||
d->trust == rrset_trust_auth_noAA ||
d->trust == rrset_trust_add_AA ||
d->trust == rrset_trust_auth_AA) {
lock_rw_unlock(&rrset->entry.lock);
continue;
}
/* create msg if none */
if(!msg) {
msg = dns_msg_create(qname, qnamelen, qtype, qclass,
region, (size_t)(num-i));
if(!msg) {
lock_rw_unlock(&rrset->entry.lock);
return NULL;
}
}
/* add RRset to response */
if(!dns_msg_ansadd(msg, region, rrset, now)) {
lock_rw_unlock(&rrset->entry.lock);
return NULL;
}
lock_rw_unlock(&rrset->entry.lock);
}
return msg;
}
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);
}
}
/* 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;
}
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, uint16_t flags)
{
struct reply_info* rep = NULL;
/* alloc, malloc properly (not in region, like msg is) */
rep = reply_info_copy(msgrep, env->alloc, NULL);
if(!rep)
return 0;
/* ttl must be relative ;i.e. 0..86400 not time(0)+86400.
* the env->now is added to message and RRsets in this routine. */
/* the leeway is used to invalidate other rrsets earlier */
if(is_referral) {
/* store rrsets */
struct rrset_ref ref;
size_t i;
for(i=0; i<rep->rrset_count; i++) {
packed_rrset_ttl_add((struct packed_rrset_data*)
rep->rrsets[i]->entry.data, *env->now);
ref.key = rep->rrsets[i];
ref.id = rep->rrsets[i]->id;
/*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 +
((ntohs(ref.key->rk.type)==LDNS_RR_TYPE_NS
&& !pside) ? 0:leeway));
}
free(rep);
return 1;
} else {
/* store msg, and rrsets */
struct query_info qinf;
hashvalue_t h;
qinf = *msgqinf;
qinf.qname = memdup(msgqinf->qname, msgqinf->qname_len);
if(!qinf.qname) {
reply_info_parsedelete(rep, env->alloc);
return 0;
}
/* fixup flags to be sensible for a reply based on the cache */
/* this module means that RA is available. It is an answer QR.
* Not AA from cache. Not CD in cache (depends on client bit). */
rep->flags |= (BIT_RA | BIT_QR);
rep->flags &= ~(BIT_AA | BIT_CD);
h = query_info_hash(&qinf, flags);
dns_cache_store_msg(env, &qinf, h, rep, leeway, pside, msgrep,
region);
/* 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);
}
return 1;
}
int
dns_cache_prefetch_adjust(struct module_env* env, struct query_info* qinfo,
time_t adjust, uint16_t flags)
{
struct msgreply_entry* msg;
msg = msg_cache_lookup(env, qinfo->qname, qinfo->qname_len,
qinfo->qtype, qinfo->qclass, flags, *env->now, 1);
if(msg) {
struct reply_info* rep = (struct reply_info*)msg->entry.data;
if(rep) {
rep->prefetch_ttl += adjust;
lock_rw_unlock(&msg->entry.lock);
return 1;
}
lock_rw_unlock(&msg->entry.lock);
}
return 0;
}
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