monero/external/unbound/services/cache/rrset.c
Erik de Castro Lopo a85b5759f3 Upgrade unbound library
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

420 lines
13 KiB
C

/*
* services/cache/rrset.c - Resource record set cache.
*
* 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 rrset cache.
*/
#include "config.h"
#include "services/cache/rrset.h"
#include "sldns/rrdef.h"
#include "util/storage/slabhash.h"
#include "util/config_file.h"
#include "util/data/packed_rrset.h"
#include "util/data/msgreply.h"
#include "util/regional.h"
#include "util/alloc.h"
void
rrset_markdel(void* key)
{
struct ub_packed_rrset_key* r = (struct ub_packed_rrset_key*)key;
r->id = 0;
}
struct rrset_cache* rrset_cache_create(struct config_file* cfg,
struct alloc_cache* alloc)
{
size_t slabs = (cfg?cfg->rrset_cache_slabs:HASH_DEFAULT_SLABS);
size_t startarray = HASH_DEFAULT_STARTARRAY;
size_t maxmem = (cfg?cfg->rrset_cache_size:HASH_DEFAULT_MAXMEM);
struct rrset_cache *r = (struct rrset_cache*)slabhash_create(slabs,
startarray, maxmem, ub_rrset_sizefunc, ub_rrset_compare,
ub_rrset_key_delete, rrset_data_delete, alloc);
slabhash_setmarkdel(&r->table, &rrset_markdel);
return r;
}
void rrset_cache_delete(struct rrset_cache* r)
{
if(!r)
return;
slabhash_delete(&r->table);
/* slabhash delete also does free(r), since table is first in struct*/
}
struct rrset_cache* rrset_cache_adjust(struct rrset_cache *r,
struct config_file* cfg, struct alloc_cache* alloc)
{
if(!r || !cfg || cfg->rrset_cache_slabs != r->table.size ||
cfg->rrset_cache_size != slabhash_get_size(&r->table))
{
rrset_cache_delete(r);
r = rrset_cache_create(cfg, alloc);
}
return r;
}
void
rrset_cache_touch(struct rrset_cache* r, struct ub_packed_rrset_key* key,
hashvalue_type hash, rrset_id_type id)
{
struct lruhash* table = slabhash_gettable(&r->table, hash);
/*
* This leads to locking problems, deadlocks, if the caller is
* holding any other rrset lock.
* Because a lookup through the hashtable does:
* tablelock -> entrylock (for that entry caller holds)
* And this would do
* entrylock(already held) -> tablelock
* And if two threads do this, it results in deadlock.
* So, the caller must not hold entrylock.
*/
lock_quick_lock(&table->lock);
/* we have locked the hash table, the item can still be deleted.
* because it could already have been reclaimed, but not yet set id=0.
* This is because some lruhash routines have lazy deletion.
* so, we must acquire a lock on the item to verify the id != 0.
* also, with hash not changed, we are using the right slab.
*/
lock_rw_rdlock(&key->entry.lock);
if(key->id == id && key->entry.hash == hash) {
lru_touch(table, &key->entry);
}
lock_rw_unlock(&key->entry.lock);
lock_quick_unlock(&table->lock);
}
/** see if rrset needs to be updated in the cache */
static int
need_to_update_rrset(void* nd, void* cd, time_t timenow, int equal, int ns)
{
struct packed_rrset_data* newd = (struct packed_rrset_data*)nd;
struct packed_rrset_data* cached = (struct packed_rrset_data*)cd;
/* o store if rrset has been validated
* everything better than bogus data
* secure is preferred */
if( newd->security == sec_status_secure &&
cached->security != sec_status_secure)
return 1;
if( cached->security == sec_status_bogus &&
newd->security != sec_status_bogus && !equal)
return 1;
/* o if current RRset is more trustworthy - insert it */
if( newd->trust > cached->trust ) {
/* if the cached rrset is bogus, and this one equal,
* do not update the TTL - let it expire. */
if(equal && cached->ttl >= timenow &&
cached->security == sec_status_bogus)
return 0;
return 1;
}
/* o item in cache has expired */
if( cached->ttl < timenow )
return 1;
/* o same trust, but different in data - insert it */
if( newd->trust == cached->trust && !equal ) {
/* if this is type NS, do not 'stick' to owner that changes
* the NS RRset, but use the old TTL for the new data, and
* update to fetch the latest data. ttl is not expired, because
* that check was before this one. */
if(ns) {
size_t i;
newd->ttl = cached->ttl;
for(i=0; i<(newd->count+newd->rrsig_count); i++)
if(newd->rr_ttl[i] > newd->ttl)
newd->rr_ttl[i] = newd->ttl;
}
return 1;
}
return 0;
}
/** Update RRSet special key ID */
static void
rrset_update_id(struct rrset_ref* ref, struct alloc_cache* alloc)
{
/* this may clear the cache and invalidate lock below */
uint64_t newid = alloc_get_id(alloc);
/* obtain writelock */
lock_rw_wrlock(&ref->key->entry.lock);
/* check if it was deleted in the meantime, if so, skip update */
if(ref->key->id == ref->id) {
ref->key->id = newid;
ref->id = newid;
}
lock_rw_unlock(&ref->key->entry.lock);
}
int
rrset_cache_update(struct rrset_cache* r, struct rrset_ref* ref,
struct alloc_cache* alloc, time_t timenow)
{
struct lruhash_entry* e;
struct ub_packed_rrset_key* k = ref->key;
hashvalue_type h = k->entry.hash;
uint16_t rrset_type = ntohs(k->rk.type);
int equal = 0;
log_assert(ref->id != 0 && k->id != 0);
log_assert(k->rk.dname != NULL);
/* looks up item with a readlock - no editing! */
if((e=slabhash_lookup(&r->table, h, k, 0)) != 0) {
/* return id and key as they will be used in the cache
* since the lruhash_insert, if item already exists, deallocs
* the passed key in favor of the already stored key.
* because of the small gap (see below) this key ptr and id
* may prove later to be already deleted, which is no problem
* as it only makes a cache miss.
*/
ref->key = (struct ub_packed_rrset_key*)e->key;
ref->id = ref->key->id;
equal = rrsetdata_equal((struct packed_rrset_data*)k->entry.
data, (struct packed_rrset_data*)e->data);
if(!need_to_update_rrset(k->entry.data, e->data, timenow,
equal, (rrset_type==LDNS_RR_TYPE_NS))) {
/* cache is superior, return that value */
lock_rw_unlock(&e->lock);
ub_packed_rrset_parsedelete(k, alloc);
if(equal) return 2;
return 1;
}
lock_rw_unlock(&e->lock);
/* Go on and insert the passed item.
* small gap here, where entry is not locked.
* possibly entry is updated with something else.
* we then overwrite that with our data.
* this is just too bad, its cache anyway. */
/* use insert to update entry to manage lruhash
* cache size values nicely. */
}
log_assert(ref->key->id != 0);
slabhash_insert(&r->table, h, &k->entry, k->entry.data, alloc);
if(e) {
/* For NSEC, NSEC3, DNAME, when rdata is updated, update
* the ID number so that proofs in message cache are
* invalidated */
if((rrset_type == LDNS_RR_TYPE_NSEC
|| rrset_type == LDNS_RR_TYPE_NSEC3
|| rrset_type == LDNS_RR_TYPE_DNAME) && !equal) {
rrset_update_id(ref, alloc);
}
return 1;
}
return 0;
}
struct ub_packed_rrset_key*
rrset_cache_lookup(struct rrset_cache* r, uint8_t* qname, size_t qnamelen,
uint16_t qtype, uint16_t qclass, uint32_t flags, time_t timenow,
int wr)
{
struct lruhash_entry* e;
struct ub_packed_rrset_key key;
key.entry.key = &key;
key.entry.data = NULL;
key.rk.dname = qname;
key.rk.dname_len = qnamelen;
key.rk.type = htons(qtype);
key.rk.rrset_class = htons(qclass);
key.rk.flags = flags;
key.entry.hash = rrset_key_hash(&key.rk);
if((e = slabhash_lookup(&r->table, key.entry.hash, &key, wr))) {
/* check TTL */
struct packed_rrset_data* data =
(struct packed_rrset_data*)e->data;
if(timenow > data->ttl) {
lock_rw_unlock(&e->lock);
return NULL;
}
/* we're done */
return (struct ub_packed_rrset_key*)e->key;
}
return NULL;
}
int
rrset_array_lock(struct rrset_ref* ref, size_t count, time_t timenow)
{
size_t i;
for(i=0; i<count; i++) {
if(i>0 && ref[i].key == ref[i-1].key)
continue; /* only lock items once */
lock_rw_rdlock(&ref[i].key->entry.lock);
if(ref[i].id != ref[i].key->id || timenow >
((struct packed_rrset_data*)(ref[i].key->entry.data))
->ttl) {
/* failure! rollback our readlocks */
rrset_array_unlock(ref, i+1);
return 0;
}
}
return 1;
}
void
rrset_array_unlock(struct rrset_ref* ref, size_t count)
{
size_t i;
for(i=0; i<count; i++) {
if(i>0 && ref[i].key == ref[i-1].key)
continue; /* only unlock items once */
lock_rw_unlock(&ref[i].key->entry.lock);
}
}
void
rrset_array_unlock_touch(struct rrset_cache* r, struct regional* scratch,
struct rrset_ref* ref, size_t count)
{
hashvalue_type* h;
size_t i;
if(count > RR_COUNT_MAX || !(h = (hashvalue_type*)regional_alloc(
scratch, sizeof(hashvalue_type)*count))) {
log_warn("rrset LRU: memory allocation failed");
h = NULL;
} else /* store hash values */
for(i=0; i<count; i++)
h[i] = ref[i].key->entry.hash;
/* unlock */
for(i=0; i<count; i++) {
if(i>0 && ref[i].key == ref[i-1].key)
continue; /* only unlock items once */
lock_rw_unlock(&ref[i].key->entry.lock);
}
if(h) {
/* LRU touch, with no rrset locks held */
for(i=0; i<count; i++) {
if(i>0 && ref[i].key == ref[i-1].key)
continue; /* only touch items once */
rrset_cache_touch(r, ref[i].key, h[i], ref[i].id);
}
}
}
void
rrset_update_sec_status(struct rrset_cache* r,
struct ub_packed_rrset_key* rrset, time_t now)
{
struct packed_rrset_data* updata =
(struct packed_rrset_data*)rrset->entry.data;
struct lruhash_entry* e;
struct packed_rrset_data* cachedata;
/* hash it again to make sure it has a hash */
rrset->entry.hash = rrset_key_hash(&rrset->rk);
e = slabhash_lookup(&r->table, rrset->entry.hash, rrset, 1);
if(!e)
return; /* not in the cache anymore */
cachedata = (struct packed_rrset_data*)e->data;
if(!rrsetdata_equal(updata, cachedata)) {
lock_rw_unlock(&e->lock);
return; /* rrset has changed in the meantime */
}
/* update the cached rrset */
if(updata->security > cachedata->security) {
size_t i;
if(updata->trust > cachedata->trust)
cachedata->trust = updata->trust;
cachedata->security = updata->security;
/* for NS records only shorter TTLs, other types: update it */
if(ntohs(rrset->rk.type) != LDNS_RR_TYPE_NS ||
updata->ttl+now < cachedata->ttl ||
cachedata->ttl < now ||
updata->security == sec_status_bogus) {
cachedata->ttl = updata->ttl + now;
for(i=0; i<cachedata->count+cachedata->rrsig_count; i++)
cachedata->rr_ttl[i] = updata->rr_ttl[i]+now;
}
}
lock_rw_unlock(&e->lock);
}
void
rrset_check_sec_status(struct rrset_cache* r,
struct ub_packed_rrset_key* rrset, time_t now)
{
struct packed_rrset_data* updata =
(struct packed_rrset_data*)rrset->entry.data;
struct lruhash_entry* e;
struct packed_rrset_data* cachedata;
/* hash it again to make sure it has a hash */
rrset->entry.hash = rrset_key_hash(&rrset->rk);
e = slabhash_lookup(&r->table, rrset->entry.hash, rrset, 0);
if(!e)
return; /* not in the cache anymore */
cachedata = (struct packed_rrset_data*)e->data;
if(now > cachedata->ttl || !rrsetdata_equal(updata, cachedata)) {
lock_rw_unlock(&e->lock);
return; /* expired, or rrset has changed in the meantime */
}
if(cachedata->security > updata->security) {
updata->security = cachedata->security;
if(cachedata->security == sec_status_bogus) {
size_t i;
updata->ttl = cachedata->ttl - now;
for(i=0; i<cachedata->count+cachedata->rrsig_count; i++)
if(cachedata->rr_ttl[i] < now)
updata->rr_ttl[i] = 0;
else updata->rr_ttl[i] =
cachedata->rr_ttl[i]-now;
}
if(cachedata->trust > updata->trust)
updata->trust = cachedata->trust;
}
lock_rw_unlock(&e->lock);
}
void rrset_cache_remove(struct rrset_cache* r, uint8_t* nm, size_t nmlen,
uint16_t type, uint16_t dclass, uint32_t flags)
{
struct ub_packed_rrset_key key;
key.entry.key = &key;
key.rk.dname = nm;
key.rk.dname_len = nmlen;
key.rk.rrset_class = htons(dclass);
key.rk.type = htons(type);
key.rk.flags = flags;
key.entry.hash = rrset_key_hash(&key.rk);
slabhash_remove(&r->table, key.entry.hash, &key);
}