monero/external/unbound/services/cache/rrset.c
2014-10-05 23:44:31 +02:00

417 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 "ldns/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_t hash, rrset_id_t 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_t h = k->entry.hash;
uint16_t rrset_type = ntohs(k->rk.type);
int equal = 0;
log_assert(ref->id != 0 && k->id != 0);
/* 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_t* h;
size_t i;
if(!(h = (hashvalue_t*)regional_alloc(scratch,
sizeof(hashvalue_t)*count)))
log_warn("rrset LRU: memory allocation failed");
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);
}