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bind9/lib/dns/qpcache.c
Daniel Baumann f66ff7eae6
Adding upstream version 1:9.20.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-21 13:32:37 +02:00

4367 lines
116 KiB
C

/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file */
#include <inttypes.h>
#include <stdalign.h>
#include <stdbool.h>
#include <sys/mman.h>
#include <isc/ascii.h>
#include <isc/async.h>
#include <isc/atomic.h>
#include <isc/crc64.h>
#include <isc/file.h>
#include <isc/heap.h>
#include <isc/hex.h>
#include <isc/loop.h>
#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/os.h>
#include <isc/queue.h>
#include <isc/random.h>
#include <isc/refcount.h>
#include <isc/result.h>
#include <isc/rwlock.h>
#include <isc/stdio.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/urcu.h>
#include <isc/util.h>
#include <dns/callbacks.h>
#include <dns/db.h>
#include <dns/dbiterator.h>
#include <dns/fixedname.h>
#include <dns/log.h>
#include <dns/masterdump.h>
#include <dns/nsec.h>
#include <dns/qp.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdataslab.h>
#include <dns/rdatastruct.h>
#include <dns/stats.h>
#include <dns/time.h>
#include <dns/view.h>
#include <dns/zonekey.h>
#include "db_p.h"
#include "qpcache_p.h"
#define CHECK(op) \
do { \
result = (op); \
if (result != ISC_R_SUCCESS) \
goto failure; \
} while (0)
#define EXISTS(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_NONEXISTENT) == 0)
#define NONEXISTENT(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_NONEXISTENT) != 0)
#define IGNORE(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_IGNORE) != 0)
#define NXDOMAIN(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_NXDOMAIN) != 0)
#define STALE(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_STALE) != 0)
#define STALE_WINDOW(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_STALE_WINDOW) != 0)
#define OPTOUT(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_OPTOUT) != 0)
#define NEGATIVE(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_NEGATIVE) != 0)
#define PREFETCH(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_PREFETCH) != 0)
#define ZEROTTL(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_ZEROTTL) != 0)
#define ANCIENT(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_ANCIENT) != 0)
#define STATCOUNT(header) \
((atomic_load_acquire(&(header)->attributes) & \
DNS_SLABHEADERATTR_STATCOUNT) != 0)
#define STALE_TTL(header, qpdb) \
(NXDOMAIN(header) ? 0 : qpdb->common.serve_stale_ttl)
#define ACTIVE(header, now) \
(((header)->ttl > (now)) || ((header)->ttl == (now) && ZEROTTL(header)))
#define EXPIREDOK(iterator) \
(((iterator)->common.options & DNS_DB_EXPIREDOK) != 0)
#define STALEOK(iterator) (((iterator)->common.options & DNS_DB_STALEOK) != 0)
#define KEEPSTALE(qpdb) ((qpdb)->common.serve_stale_ttl > 0)
/*%
* Note that "impmagic" is not the first four bytes of the struct, so
* ISC_MAGIC_VALID cannot be used.
*/
#define QPDB_MAGIC ISC_MAGIC('Q', 'P', 'D', '4')
#define VALID_QPDB(qpdb) \
((qpdb) != NULL && (qpdb)->common.impmagic == QPDB_MAGIC)
#define HEADERNODE(h) ((qpcnode_t *)((h)->node))
/*
* Allow clients with a virtual time of up to 5 minutes in the past to see
* records that would have otherwise have expired.
*/
#define QPDB_VIRTUAL 300
/*%
* Whether to rate-limit updating the LRU to avoid possible thread contention.
* Updating LRU requires write locking, so we don't do it every time the
* record is touched - only after some time passes.
*/
#ifndef DNS_QPDB_LIMITLRUUPDATE
#define DNS_QPDB_LIMITLRUUPDATE 1
#endif
/*% Time after which we update LRU for glue records, 5 minutes */
#define DNS_QPDB_LRUUPDATE_GLUE 300
/*% Time after which we update LRU for all other records, 10 minutes */
#define DNS_QPDB_LRUUPDATE_REGULAR 600
/*
* This defines the number of headers that we try to expire each time the
* expire_ttl_headers() is run. The number should be small enough, so the
* TTL-based header expiration doesn't take too long, but it should be large
* enough, so we expire enough headers if their TTL is clustered.
*/
#define DNS_QPDB_EXPIRE_TTL_COUNT 10
/*%
* This is the structure that is used for each node in the qp trie of trees.
*/
typedef struct qpcnode qpcnode_t;
struct qpcnode {
dns_name_t name;
isc_mem_t *mctx;
uint8_t : 0;
unsigned int delegating : 1;
unsigned int nsec : 2; /*%< range is 0..3 */
uint8_t : 0;
uint16_t locknum;
/*
* 'erefs' counts external references held by a caller: for
* example, it could be incremented by dns_db_findnode(),
* and decremented by dns_db_detachnode().
*
* 'references' counts internal references to the node object,
* including the one held by the QP trie so the node won't be
* deleted while it's quiescently stored in the database - even
* though 'erefs' may be zero because no external caller is
* using it at the time.
*
* Generally when 'erefs' is incremented or decremented,
* 'references' is too. When both go to zero (meaning callers
* and the database have both released the object) the object
* is freed.
*
* Whenever 'erefs' is incremented from zero, we also aquire a
* node use reference (see 'qpcache->references' below), and
* release it when 'erefs' goes back to zero. This prevents the
* database from being shut down until every caller has released
* all nodes.
*/
isc_refcount_t references;
isc_refcount_t erefs;
void *data;
/*%
* NOTE: The 'dirty' flag is protected by the node lock, so
* this bitfield has to be separated from the one above.
* We don't want it to share the same qword with bits
* that can be accessed without the node lock.
*/
uint8_t : 0;
uint8_t dirty : 1;
uint8_t : 0;
/*%
* Used for dead nodes cleaning. This linked list is used to mark nodes
* which have no data any longer, but we cannot unlink at that exact
* moment because we did not or could not obtain a write lock on the
* tree.
*/
isc_queue_node_t deadlink;
};
/*%
* One bucket structure will be created for each loop, and
* nodes in the database will evenly distributed among buckets
* to reduce contention between threads.
*/
typedef struct qpcache_bucket {
/*%
* Temporary storage for stale cache nodes and dynamically
* deleted nodes that await being cleaned up.
*/
isc_queue_t deadnodes;
/* Per-bucket lock. */
isc_rwlock_t lock;
/*
* Linked list used to implement LRU cache cleaning.
*/
dns_slabheaderlist_t lru;
/*
* The heap is used for TTL based expiry. Note that qpcache->hmctx
* is the memory context to use for heap memory; this differs from
* the main database memory context, which is qpcache->common.mctx.
*/
isc_heap_t *heap;
/* Padding to prevent false sharing between locks. */
uint8_t __padding[ISC_OS_CACHELINE_SIZE -
(sizeof(isc_queue_t) + sizeof(isc_rwlock_t) +
sizeof(dns_slabheaderlist_t) + sizeof(isc_heap_t *)) %
ISC_OS_CACHELINE_SIZE];
} qpcache_bucket_t;
typedef struct qpcache qpcache_t;
struct qpcache {
/* Unlocked. */
dns_db_t common;
/* Loopmgr */
isc_loopmgr_t *loopmgr;
/* Locks the data in this struct */
isc_rwlock_t lock;
/* Locks the tree structure (prevents nodes appearing/disappearing) */
isc_rwlock_t tree_lock;
/*
* NOTE: 'references' is NOT the global reference counter for
* the database object handled by dns_db_attach() and _detach();
* that one is 'common.references'.
*
* Instead, 'references' counts the number of nodes being used by
* at least one external caller. (It's called 'references' to
* leverage the ISC_REFCOUNT_STATIC macros, but 'nodes_in_use'
* might be a clearer name.)
*
* One additional reference to this counter is held by the database
* object itself. When 'common.references' goes to zero, that
* reference is released. When in turn 'references' goes to zero,
* the database is shut down and freed.
*/
isc_refcount_t references;
dns_stats_t *rrsetstats;
isc_stats_t *cachestats;
uint32_t maxrrperset; /* Maximum RRs per RRset */
uint32_t maxtypepername; /* Maximum number of RR types per owner */
/*
* The time after a failed lookup, where stale answers from cache
* may be used directly in a DNS response without attempting a
* new iterative lookup.
*/
uint32_t serve_stale_refresh;
/*
* Start point % node_lock_count for next LRU cleanup.
*/
atomic_uint lru_sweep;
/*
* When performing LRU cleaning limit cleaning to headers that were
* last used at or before this.
*/
_Atomic(isc_stdtime_t) last_used;
/* Locked by tree_lock. */
dns_qp_t *tree;
dns_qp_t *nsec;
isc_mem_t *hmctx; /* Memory context for the heaps */
size_t buckets_count;
qpcache_bucket_t buckets[]; /* attribute((counted_by(buckets_count))) */
};
#ifdef DNS_DB_NODETRACE
#define qpcache_ref(ptr) qpcache__ref(ptr, __func__, __FILE__, __LINE__)
#define qpcache_unref(ptr) qpcache__unref(ptr, __func__, __FILE__, __LINE__)
#define qpcache_attach(ptr, ptrp) \
qpcache__attach(ptr, ptrp, __func__, __FILE__, __LINE__)
#define qpcache_detach(ptrp) qpcache__detach(ptrp, __func__, __FILE__, __LINE__)
ISC_REFCOUNT_STATIC_TRACE_DECL(qpcache);
#else
ISC_REFCOUNT_STATIC_DECL(qpcache);
#endif
/*%
* Search Context
*/
typedef struct {
qpcache_t *qpdb;
unsigned int options;
dns_qpchain_t chain;
dns_qpiter_t iter;
bool need_cleanup;
qpcnode_t *zonecut;
dns_slabheader_t *zonecut_header;
dns_slabheader_t *zonecut_sigheader;
isc_stdtime_t now;
} qpc_search_t;
#ifdef DNS_DB_NODETRACE
#define qpcnode_ref(ptr) qpcnode__ref(ptr, __func__, __FILE__, __LINE__)
#define qpcnode_unref(ptr) qpcnode__unref(ptr, __func__, __FILE__, __LINE__)
#define qpcnode_attach(ptr, ptrp) \
qpcnode__attach(ptr, ptrp, __func__, __FILE__, __LINE__)
#define qpcnode_detach(ptrp) qpcnode__detach(ptrp, __func__, __FILE__, __LINE__)
ISC_REFCOUNT_STATIC_TRACE_DECL(qpcnode);
#else
ISC_REFCOUNT_STATIC_DECL(qpcnode);
#endif
/* QP methods */
static void
qp_attach(void *uctx, void *pval, uint32_t ival);
static void
qp_detach(void *uctx, void *pval, uint32_t ival);
static size_t
qp_makekey(dns_qpkey_t key, void *uctx, void *pval, uint32_t ival);
static void
qp_triename(void *uctx, char *buf, size_t size);
static dns_qpmethods_t qpmethods = {
qp_attach,
qp_detach,
qp_makekey,
qp_triename,
};
static void
qp_attach(void *uctx ISC_ATTR_UNUSED, void *pval,
uint32_t ival ISC_ATTR_UNUSED) {
qpcnode_t *data = pval;
qpcnode_ref(data);
}
static void
qp_detach(void *uctx ISC_ATTR_UNUSED, void *pval,
uint32_t ival ISC_ATTR_UNUSED) {
qpcnode_t *data = pval;
qpcnode_detach(&data);
}
static size_t
qp_makekey(dns_qpkey_t key, void *uctx ISC_ATTR_UNUSED, void *pval,
uint32_t ival ISC_ATTR_UNUSED) {
qpcnode_t *data = pval;
return dns_qpkey_fromname(key, &data->name);
}
static void
qp_triename(void *uctx, char *buf, size_t size) {
UNUSED(uctx);
snprintf(buf, size, "qpdb-lite");
}
static void
rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp DNS__DB_FLARG);
static isc_result_t
rdatasetiter_first(dns_rdatasetiter_t *iterator DNS__DB_FLARG);
static isc_result_t
rdatasetiter_next(dns_rdatasetiter_t *iterator DNS__DB_FLARG);
static void
rdatasetiter_current(dns_rdatasetiter_t *iterator,
dns_rdataset_t *rdataset DNS__DB_FLARG);
static dns_rdatasetitermethods_t rdatasetiter_methods = {
rdatasetiter_destroy, rdatasetiter_first, rdatasetiter_next,
rdatasetiter_current
};
typedef struct qpc_rditer {
dns_rdatasetiter_t common;
dns_slabheader_t *current;
} qpc_rditer_t;
static void
dbiterator_destroy(dns_dbiterator_t **iteratorp DNS__DB_FLARG);
static isc_result_t
dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG);
static isc_result_t
dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG);
static isc_result_t
dbiterator_seek(dns_dbiterator_t *iterator,
const dns_name_t *name DNS__DB_FLARG);
static isc_result_t
dbiterator_prev(dns_dbiterator_t *iterator DNS__DB_FLARG);
static isc_result_t
dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG);
static isc_result_t
dbiterator_current(dns_dbiterator_t *iterator, dns_dbnode_t **nodep,
dns_name_t *name DNS__DB_FLARG);
static isc_result_t
dbiterator_pause(dns_dbiterator_t *iterator);
static isc_result_t
dbiterator_origin(dns_dbiterator_t *iterator, dns_name_t *name);
static dns_dbiteratormethods_t dbiterator_methods = {
dbiterator_destroy, dbiterator_first, dbiterator_last,
dbiterator_seek, dbiterator_prev, dbiterator_next,
dbiterator_current, dbiterator_pause, dbiterator_origin
};
/*
* Note that the QP cache database only needs a single QP iterator, because
* unlike the QP zone database, NSEC3 records are cached in the main tree.
*
* If we ever implement synth-from-dnssec using NSEC3 records, we'll need
* to have a separate tree for NSEC3 records, and to copy in the more complex
* iterator implementation from qpzone.c.
*/
typedef struct qpc_dbit {
dns_dbiterator_t common;
bool paused;
isc_rwlocktype_t tree_locked;
isc_result_t result;
dns_fixedname_t fixed;
dns_name_t *name;
dns_qpiter_t iter;
qpcnode_t *node;
} qpc_dbit_t;
static void
qpcache__destroy(qpcache_t *qpdb);
static dns_dbmethods_t qpdb_cachemethods;
/*%
* 'init_count' is used to initialize 'newheader->count' which in turn
* is used to determine where in the cycle rrset-order cyclic starts.
* We don't lock this as we don't care about simultaneous updates.
*/
static atomic_uint_fast16_t init_count = 0;
/*
* Locking
*
* If a routine is going to lock more than one lock in this module, then
* the locking must be done in the following order:
*
* Tree Lock
*
* Node Lock (Only one from the set may be locked at one time by
* any caller)
*
* Database Lock
*
* Failure to follow this hierarchy can result in deadlock.
*/
/*%
* Routines for LRU-based cache management.
*/
/*%
* See if a given cache entry that is being reused needs to be updated
* in the LRU-list. From the LRU management point of view, this function is
* expected to return true for almost all cases. When used with threads,
* however, this may cause a non-negligible performance penalty because a
* writer lock will have to be acquired before updating the list.
* If DNS_QPDB_LIMITLRUUPDATE is defined to be non 0 at compilation time, this
* function returns true if the entry has not been updated for some period of
* time. We differentiate the NS or glue address case and the others since
* experiments have shown that the former tends to be accessed relatively
* infrequently and the cost of cache miss is higher (e.g., a missing NS records
* may cause external queries at a higher level zone, involving more
* transactions).
*
* Caller must hold the node (read or write) lock.
*/
static bool
need_headerupdate(dns_slabheader_t *header, isc_stdtime_t now) {
if (DNS_SLABHEADER_GETATTR(header, (DNS_SLABHEADERATTR_NONEXISTENT |
DNS_SLABHEADERATTR_ANCIENT |
DNS_SLABHEADERATTR_ZEROTTL)) != 0)
{
return false;
}
#if DNS_QPDB_LIMITLRUUPDATE
if (header->type == dns_rdatatype_ns ||
(header->trust == dns_trust_glue &&
(header->type == dns_rdatatype_a ||
header->type == dns_rdatatype_aaaa)))
{
/*
* Glue records are updated if at least DNS_QPDB_LRUUPDATE_GLUE
* seconds have passed since the previous update time.
*/
return header->last_used + DNS_QPDB_LRUUPDATE_GLUE <= now;
}
/*
* Other records are updated if DNS_QPDB_LRUUPDATE_REGULAR seconds
* have passed.
*/
return header->last_used + DNS_QPDB_LRUUPDATE_REGULAR <= now;
#else
UNUSED(now);
return true;
#endif /* if DNS_QPDB_LIMITLRUUPDATE */
}
/*%
* Update the timestamp of a given cache entry and move it to the head
* of the corresponding LRU list.
*
* Caller must hold the node (write) lock.
*
* Note that the we do NOT touch the heap here, as the TTL has not changed.
*/
static void
update_header(qpcache_t *qpdb, dns_slabheader_t *header, isc_stdtime_t now) {
/* To be checked: can we really assume this? XXXMLG */
INSIST(ISC_LINK_LINKED(header, link));
ISC_LIST_UNLINK(qpdb->buckets[HEADERNODE(header)->locknum].lru, header,
link);
header->last_used = now;
ISC_LIST_PREPEND(qpdb->buckets[HEADERNODE(header)->locknum].lru, header,
link);
}
/*
* Locking:
* If a routine is going to lock more than one lock in this module, then
* the locking must be done in the following order:
*
* Tree Lock
*
* Node Lock (Only one from the set may be locked at one time by
* any caller)
*
* Database Lock
*
* Failure to follow this hierarchy can result in deadlock.
*
* Deleting Nodes:
* For zone databases the node for the origin of the zone MUST NOT be deleted.
*/
/*
* DB Routines
*/
static void
clean_stale_headers(dns_slabheader_t *top) {
dns_slabheader_t *d = NULL, *down_next = NULL;
for (d = top->down; d != NULL; d = down_next) {
down_next = d->down;
dns_slabheader_destroy(&d);
}
top->down = NULL;
}
static void
clean_cache_node(qpcache_t *qpdb, qpcnode_t *node) {
dns_slabheader_t *current = NULL, *top_prev = NULL, *top_next = NULL;
/*
* Caller must be holding the node lock.
*/
for (current = node->data; current != NULL; current = top_next) {
top_next = current->next;
clean_stale_headers(current);
/*
* If current is nonexistent, ancient, or stale and
* we are not keeping stale, we can clean it up.
*/
if (NONEXISTENT(current) || ANCIENT(current) ||
(STALE(current) && !KEEPSTALE(qpdb)))
{
if (top_prev != NULL) {
top_prev->next = current->next;
} else {
node->data = current->next;
}
dns_slabheader_destroy(&current);
} else {
top_prev = current;
}
}
node->dirty = 0;
}
/*
* tree_lock(write) must be held.
*/
static void
delete_node(qpcache_t *qpdb, qpcnode_t *node) {
isc_result_t result = ISC_R_UNEXPECTED;
if (isc_log_wouldlog(dns_lctx, ISC_LOG_DEBUG(1))) {
char printname[DNS_NAME_FORMATSIZE];
dns_name_format(&node->name, printname, sizeof(printname));
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
DNS_LOGMODULE_CACHE, ISC_LOG_DEBUG(1),
"delete_node(): %p %s (bucket %d)", node,
printname, node->locknum);
}
switch (node->nsec) {
case DNS_DB_NSEC_HAS_NSEC:
/*
* Delete the corresponding node from the auxiliary NSEC
* tree before deleting from the main tree.
*/
result = dns_qp_deletename(qpdb->nsec, &node->name, NULL, NULL);
if (result != ISC_R_SUCCESS) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
DNS_LOGMODULE_CACHE, ISC_LOG_WARNING,
"delete_node(): "
"dns_qp_deletename: %s",
isc_result_totext(result));
}
/* FALLTHROUGH */
case DNS_DB_NSEC_NORMAL:
result = dns_qp_deletename(qpdb->tree, &node->name, NULL, NULL);
break;
case DNS_DB_NSEC_NSEC:
result = dns_qp_deletename(qpdb->nsec, &node->name, NULL, NULL);
break;
}
if (result != ISC_R_SUCCESS) {
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
DNS_LOGMODULE_CACHE, ISC_LOG_WARNING,
"delete_node(): "
"dns_qp_deletename: %s",
isc_result_totext(result));
}
}
/*
* The caller must specify its currect node and tree lock status.
* It's okay for neither lock to be held if there are existing external
* references to the node, but if this is the first external reference,
* then the caller must be holding at least one lock.
*
* If incrementing erefs from zero, we also increment the node use counter
* in the qpcache object.
*
* This function is called from qpcnode_acquire(), so that internal
* and external references are acquired at the same time, and from
* qpcnode_release() when we only need to increase the internal references.
*/
static void
qpcnode_erefs_increment(qpcache_t *qpdb, qpcnode_t *node,
isc_rwlocktype_t nlocktype,
isc_rwlocktype_t tlocktype DNS__DB_FLARG) {
uint_fast32_t refs = isc_refcount_increment0(&node->erefs);
#if DNS_DB_NODETRACE
fprintf(stderr, "incr:node:%s:%s:%u:%p->erefs = %" PRIuFAST32 "\n",
func, file, line, node, refs + 1);
#endif
if (refs > 0) {
return;
}
/*
* this is the first external reference to the node.
*
* we need to hold the node or tree lock to avoid
* incrementing the reference count while also deleting
* the node. delete_node() is always protected by both
* tree and node locks being write-locked.
*/
INSIST(nlocktype != isc_rwlocktype_none ||
tlocktype != isc_rwlocktype_none);
qpcache_ref(qpdb);
}
static void
qpcnode_acquire(qpcache_t *qpdb, qpcnode_t *node, isc_rwlocktype_t nlocktype,
isc_rwlocktype_t tlocktype DNS__DB_FLARG) {
qpcnode_ref(node);
qpcnode_erefs_increment(qpdb, node, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
}
static void
cleanup_deadnodes(void *arg);
/*
* Decrement the external references to a node. If the counter
* goes to zero, decrement the node use counter in the qpcache object
* as well, and return true. Otherwise return false.
*/
static bool
qpcnode_erefs_decrement(qpcache_t *qpdb, qpcnode_t *node DNS__DB_FLARG) {
uint_fast32_t refs = isc_refcount_decrement(&node->erefs);
#if DNS_DB_NODETRACE
fprintf(stderr, "decr:node:%s:%s:%u:%p->erefs = %" PRIuFAST32 "\n",
func, file, line, node, refs - 1);
#endif
if (refs > 1) {
return false;
}
qpcache_unref(qpdb);
return true;
}
/*
* Caller must be holding a node lock, either read or write.
*
* Note that the lock must be held even when node references are
* atomically modified; in that case the decrement operation itself does not
* have to be protected, but we must avoid a race condition where multiple
* threads are decreasing the reference to zero simultaneously and at least
* one of them is going to free the node.
*
* This calls dec_erefs() to decrement the external node reference counter,
* (and possibly the node use counter), cleans up and deletes the node
* if necessary, then decrements the internal reference counter as well.
*/
static void
qpcnode_release(qpcache_t *qpdb, qpcnode_t *node, isc_rwlocktype_t *nlocktypep,
isc_rwlocktype_t *tlocktypep, bool tryupgrade DNS__DB_FLARG) {
REQUIRE(*nlocktypep != isc_rwlocktype_none);
isc_result_t result;
bool locked = *tlocktypep != isc_rwlocktype_none;
bool write_locked = false;
if (!qpcnode_erefs_decrement(qpdb, node DNS__DB_FLARG_PASS)) {
goto unref;
}
/* Handle easy and typical case first. */
if (!node->dirty && node->data != NULL) {
goto unref;
}
if (*nlocktypep == isc_rwlocktype_read) {
/*
* The external reference count went to zero and the node
* is dirty or has no data, so we might want to delete it.
* To do that, we'll need a write lock. If we don't already
* have one, we have to make sure nobody else has
* acquired a reference in the meantime, so we increment
* erefs (but NOT references!), upgrade the node lock,
* decrement erefs again, and see if it's still zero.
*
* We can't really assume anything about the result code of
* erefs_increment. If another thread acquires reference it
* will be larger than 0, if it doesn't it is going to be 0.
*/
isc_rwlock_t *nlock = &qpdb->buckets[node->locknum].lock;
qpcnode_erefs_increment(qpdb, node, *nlocktypep,
*tlocktypep DNS__DB_FLARG_PASS);
NODE_FORCEUPGRADE(nlock, nlocktypep);
if (!qpcnode_erefs_decrement(qpdb, node DNS__DB_FLARG_PASS)) {
goto unref;
}
}
if (node->dirty) {
clean_cache_node(qpdb, node);
}
/*
* Attempt to switch to a write lock on the tree. If this fails,
* we will add this node to a linked list of nodes in this locking
* bucket which we will free later.
*
* Locking hierarchy notwithstanding, we don't need to free
* the node lock before acquiring the tree write lock because
* we only do a trylock.
*/
/* We are allowed to upgrade the tree lock */
switch (*tlocktypep) {
case isc_rwlocktype_write:
result = ISC_R_SUCCESS;
break;
case isc_rwlocktype_read:
if (tryupgrade) {
result = TREE_TRYUPGRADE(&qpdb->tree_lock, tlocktypep);
} else {
result = ISC_R_LOCKBUSY;
}
break;
case isc_rwlocktype_none:
result = TREE_TRYWRLOCK(&qpdb->tree_lock, tlocktypep);
break;
default:
UNREACHABLE();
}
RUNTIME_CHECK(result == ISC_R_SUCCESS || result == ISC_R_LOCKBUSY);
if (result == ISC_R_SUCCESS) {
write_locked = true;
}
if (node->data != NULL) {
goto restore_locks;
}
if (write_locked) {
/*
* We can now delete the node.
*/
delete_node(qpdb, node);
} else {
qpcnode_acquire(qpdb, node, *nlocktypep,
*tlocktypep DNS__DB_FLARG_PASS);
isc_queue_node_init(&node->deadlink);
if (!isc_queue_enqueue_entry(
&qpdb->buckets[node->locknum].deadnodes, node,
deadlink))
{
/* Queue was empty, trigger new cleaning */
isc_loop_t *loop = isc_loop_get(qpdb->loopmgr,
node->locknum);
isc_async_run(loop, cleanup_deadnodes, qpdb);
}
}
restore_locks:
/*
* Unlock the tree lock if it wasn't held previously.
*/
if (!locked && write_locked) {
TREE_UNLOCK(&qpdb->tree_lock, tlocktypep);
}
unref:
qpcnode_unref(node);
}
static void
update_rrsetstats(dns_stats_t *stats, const dns_typepair_t htype,
const uint_least16_t hattributes, const bool increment) {
dns_rdatastatstype_t statattributes = 0;
dns_rdatastatstype_t base = 0;
dns_rdatastatstype_t type;
dns_slabheader_t *header = &(dns_slabheader_t){
.type = htype,
.attributes = hattributes,
};
if (!EXISTS(header) || !STATCOUNT(header)) {
return;
}
if (NEGATIVE(header)) {
if (NXDOMAIN(header)) {
statattributes = DNS_RDATASTATSTYPE_ATTR_NXDOMAIN;
} else {
statattributes = DNS_RDATASTATSTYPE_ATTR_NXRRSET;
base = DNS_TYPEPAIR_COVERS(header->type);
}
} else {
base = DNS_TYPEPAIR_TYPE(header->type);
}
if (STALE(header)) {
statattributes |= DNS_RDATASTATSTYPE_ATTR_STALE;
}
if (ANCIENT(header)) {
statattributes |= DNS_RDATASTATSTYPE_ATTR_ANCIENT;
}
type = DNS_RDATASTATSTYPE_VALUE(base, statattributes);
if (increment) {
dns_rdatasetstats_increment(stats, type);
} else {
dns_rdatasetstats_decrement(stats, type);
}
}
static void
mark(dns_slabheader_t *header, uint_least16_t flag) {
uint_least16_t attributes = atomic_load_acquire(&header->attributes);
uint_least16_t newattributes = 0;
dns_stats_t *stats = NULL;
/*
* If we are already ancient there is nothing to do.
*/
do {
if ((attributes & flag) != 0) {
return;
}
newattributes = attributes | flag;
} while (!atomic_compare_exchange_weak_acq_rel(
&header->attributes, &attributes, newattributes));
/*
* Decrement and increment the stats counter for the appropriate
* RRtype.
*/
stats = dns_db_getrrsetstats(header->db);
if (stats != NULL) {
update_rrsetstats(stats, header->type, attributes, false);
update_rrsetstats(stats, header->type, newattributes, true);
}
}
static void
setttl(dns_slabheader_t *header, dns_ttl_t newttl) {
dns_ttl_t oldttl = header->ttl;
header->ttl = newttl;
if (header->db == NULL || !dns_db_iscache(header->db)) {
return;
}
/*
* This is a cache. Adjust the heaps if necessary.
*/
if (header->heap == NULL || header->heap_index == 0 || newttl == oldttl)
{
return;
}
if (newttl < oldttl) {
isc_heap_increased(header->heap, header->heap_index);
} else {
isc_heap_decreased(header->heap, header->heap_index);
}
if (newttl == 0) {
isc_heap_delete(header->heap, header->heap_index);
}
}
static void
mark_ancient(dns_slabheader_t *header) {
setttl(header, 0);
mark(header, DNS_SLABHEADERATTR_ANCIENT);
HEADERNODE(header)->dirty = 1;
}
/*
* Caller must hold the node (write) lock.
*/
static void
expireheader(dns_slabheader_t *header, isc_rwlocktype_t *nlocktypep,
isc_rwlocktype_t *tlocktypep, dns_expire_t reason DNS__DB_FLARG) {
mark_ancient(header);
if (isc_refcount_current(&HEADERNODE(header)->erefs) == 0) {
qpcache_t *qpdb = (qpcache_t *)header->db;
/*
* If no one else is using the node, we can clean it up now.
* We first need to gain a new reference to the node to meet a
* requirement of qpcnode_release().
*/
qpcnode_acquire(qpdb, HEADERNODE(header), *nlocktypep,
*tlocktypep DNS__DB_FLARG_PASS);
qpcnode_release(qpdb, HEADERNODE(header), nlocktypep,
tlocktypep, true DNS__DB_FLARG_PASS);
if (qpdb->cachestats == NULL) {
return;
}
switch (reason) {
case dns_expire_ttl:
isc_stats_increment(qpdb->cachestats,
dns_cachestatscounter_deletettl);
break;
case dns_expire_lru:
isc_stats_increment(qpdb->cachestats,
dns_cachestatscounter_deletelru);
break;
default:
break;
}
}
}
static void
update_cachestats(qpcache_t *qpdb, isc_result_t result) {
if (qpdb->cachestats == NULL) {
return;
}
switch (result) {
case DNS_R_COVERINGNSEC:
isc_stats_increment(qpdb->cachestats,
dns_cachestatscounter_coveringnsec);
FALLTHROUGH;
case ISC_R_SUCCESS:
case DNS_R_CNAME:
case DNS_R_DNAME:
case DNS_R_DELEGATION:
case DNS_R_NCACHENXDOMAIN:
case DNS_R_NCACHENXRRSET:
isc_stats_increment(qpdb->cachestats,
dns_cachestatscounter_hits);
break;
default:
isc_stats_increment(qpdb->cachestats,
dns_cachestatscounter_misses);
}
}
static void
bindrdataset(qpcache_t *qpdb, qpcnode_t *node, dns_slabheader_t *header,
isc_stdtime_t now, isc_rwlocktype_t nlocktype,
isc_rwlocktype_t tlocktype,
dns_rdataset_t *rdataset DNS__DB_FLARG) {
bool stale = STALE(header);
bool ancient = ANCIENT(header);
/*
* Caller must be holding the node reader lock.
* XXXJT: technically, we need a writer lock, since we'll increment
* the header count below. However, since the actual counter value
* doesn't matter, we prioritize performance here. (We may want to
* use atomic increment when available).
*/
if (rdataset == NULL) {
return;
}
qpcnode_acquire(qpdb, node, nlocktype, tlocktype DNS__DB_FLARG_PASS);
INSIST(rdataset->methods == NULL); /* We must be disassociated. */
/*
* Mark header stale or ancient if the RRset is no longer active.
*/
if (!ACTIVE(header, now)) {
dns_ttl_t stale_ttl = header->ttl + STALE_TTL(header, qpdb);
/*
* If this data is in the stale window keep it and if
* DNS_DBFIND_STALEOK is not set we tell the caller to
* skip this record. We skip the records with ZEROTTL
* (these records should not be cached anyway).
*/
if (!ZEROTTL(header) && KEEPSTALE(qpdb) && stale_ttl > now) {
stale = true;
} else {
/*
* We are not keeping stale, or it is outside the
* stale window. Mark ancient, i.e. ready for cleanup.
*/
ancient = true;
}
}
rdataset->methods = &dns_rdataslab_rdatasetmethods;
rdataset->rdclass = qpdb->common.rdclass;
rdataset->type = DNS_TYPEPAIR_TYPE(header->type);
rdataset->covers = DNS_TYPEPAIR_COVERS(header->type);
rdataset->ttl = !ZEROTTL(header) ? header->ttl - now : 0;
rdataset->ttl = header->ttl - now;
rdataset->trust = header->trust;
rdataset->resign = 0;
if (NEGATIVE(header)) {
rdataset->attributes |= DNS_RDATASETATTR_NEGATIVE;
}
if (NXDOMAIN(header)) {
rdataset->attributes |= DNS_RDATASETATTR_NXDOMAIN;
}
if (OPTOUT(header)) {
rdataset->attributes |= DNS_RDATASETATTR_OPTOUT;
}
if (PREFETCH(header)) {
rdataset->attributes |= DNS_RDATASETATTR_PREFETCH;
}
if (stale && !ancient) {
dns_ttl_t stale_ttl = header->ttl + STALE_TTL(header, qpdb);
if (stale_ttl > now) {
rdataset->ttl = stale_ttl - now;
} else {
rdataset->ttl = 0;
}
if (STALE_WINDOW(header)) {
rdataset->attributes |= DNS_RDATASETATTR_STALE_WINDOW;
}
rdataset->attributes |= DNS_RDATASETATTR_STALE;
rdataset->expire = header->ttl;
} else if (!ACTIVE(header, now)) {
rdataset->attributes |= DNS_RDATASETATTR_ANCIENT;
rdataset->ttl = 0;
}
rdataset->count = atomic_fetch_add_relaxed(&header->count, 1);
rdataset->slab.db = (dns_db_t *)qpdb;
rdataset->slab.node = (dns_dbnode_t *)node;
rdataset->slab.raw = dns_slabheader_raw(header);
rdataset->slab.iter_pos = NULL;
rdataset->slab.iter_count = 0;
/*
* Add noqname proof.
*/
rdataset->slab.noqname = header->noqname;
if (header->noqname != NULL) {
rdataset->attributes |= DNS_RDATASETATTR_NOQNAME;
}
rdataset->slab.closest = header->closest;
if (header->closest != NULL) {
rdataset->attributes |= DNS_RDATASETATTR_CLOSEST;
}
}
static isc_result_t
setup_delegation(qpc_search_t *search, dns_dbnode_t **nodep,
dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
isc_rwlocktype_t tlocktype DNS__DB_FLARG) {
dns_typepair_t type;
qpcnode_t *node = NULL;
REQUIRE(search != NULL);
REQUIRE(search->zonecut != NULL);
REQUIRE(search->zonecut_header != NULL);
/*
* The caller MUST NOT be holding any node locks.
*/
node = search->zonecut;
type = search->zonecut_header->type;
if (nodep != NULL) {
/*
* Note that we don't have to increment the node's reference
* count here because we're going to use the reference we
* already have in the search block.
*/
*nodep = node;
search->need_cleanup = false;
}
if (rdataset != NULL) {
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock =
&search->qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
bindrdataset(search->qpdb, node, search->zonecut_header,
search->now, nlocktype, tlocktype,
rdataset DNS__DB_FLARG_PASS);
if (sigrdataset != NULL && search->zonecut_sigheader != NULL) {
bindrdataset(search->qpdb, node,
search->zonecut_sigheader, search->now,
nlocktype, tlocktype,
sigrdataset DNS__DB_FLARG_PASS);
}
NODE_UNLOCK(nlock, &nlocktype);
}
if (type == dns_rdatatype_dname) {
return DNS_R_DNAME;
}
return DNS_R_DELEGATION;
}
static bool
check_stale_header(qpcnode_t *node, dns_slabheader_t *header,
isc_rwlocktype_t *nlocktypep, isc_rwlock_t *nlock,
qpc_search_t *search, dns_slabheader_t **header_prev) {
if (!ACTIVE(header, search->now)) {
dns_ttl_t stale = header->ttl + STALE_TTL(header, search->qpdb);
/*
* If this data is in the stale window keep it and if
* DNS_DBFIND_STALEOK is not set we tell the caller to
* skip this record. We skip the records with ZEROTTL
* (these records should not be cached anyway).
*/
DNS_SLABHEADER_CLRATTR(header, DNS_SLABHEADERATTR_STALE_WINDOW);
if (!ZEROTTL(header) && KEEPSTALE(search->qpdb) &&
stale > search->now)
{
mark(header, DNS_SLABHEADERATTR_STALE);
*header_prev = header;
/*
* If DNS_DBFIND_STALESTART is set then it means we
* failed to resolve the name during recursion, in
* this case we mark the time in which the refresh
* failed.
*/
if ((search->options & DNS_DBFIND_STALESTART) != 0) {
atomic_store_release(
&header->last_refresh_fail_ts,
search->now);
} else if ((search->options &
DNS_DBFIND_STALEENABLED) != 0 &&
search->now <
(atomic_load_acquire(
&header->last_refresh_fail_ts) +
search->qpdb->serve_stale_refresh))
{
/*
* If we are within interval between last
* refresh failure time + 'stale-refresh-time',
* then don't skip this stale entry but use it
* instead.
*/
DNS_SLABHEADER_SETATTR(
header,
DNS_SLABHEADERATTR_STALE_WINDOW);
return false;
} else if ((search->options &
DNS_DBFIND_STALETIMEOUT) != 0)
{
/*
* We want stale RRset due to timeout, so we
* don't skip it.
*/
return false;
}
return (search->options & DNS_DBFIND_STALEOK) == 0;
}
/*
* This rdataset is stale. If no one else is using the
* node, we can clean it up right now, otherwise we mark
* it as ancient, and the node as dirty, so it will get
* cleaned up later.
*/
if ((header->ttl < search->now - QPDB_VIRTUAL) &&
(*nlocktypep == isc_rwlocktype_write ||
NODE_TRYUPGRADE(nlock, nlocktypep) == ISC_R_SUCCESS))
{
/*
* We update the node's status only when we can
* get write access; otherwise, we leave others
* to this work. Periodical cleaning will
* eventually take the job as the last resort.
* We won't downgrade the lock, since other
* rdatasets are probably stale, too.
*/
if (isc_refcount_current(&node->references) == 0) {
/*
* header->down can be non-NULL if the
* refcount has just decremented to 0
* but qpcnode_release() has not
* performed clean_cache_node(), in
* which case we need to purge the stale
* headers first.
*/
clean_stale_headers(header);
if (*header_prev != NULL) {
(*header_prev)->next = header->next;
} else {
node->data = header->next;
}
dns_slabheader_destroy(&header);
} else {
mark_ancient(header);
*header_prev = header;
}
} else {
*header_prev = header;
}
return true;
}
return false;
}
static isc_result_t
check_zonecut(qpcnode_t *node, void *arg DNS__DB_FLARG) {
qpc_search_t *search = arg;
dns_slabheader_t *header = NULL;
dns_slabheader_t *header_prev = NULL, *header_next = NULL;
dns_slabheader_t *dname_header = NULL, *sigdname_header = NULL;
isc_result_t result;
isc_rwlock_t *nlock = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
REQUIRE(search->zonecut == NULL);
nlock = &search->qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
/*
* Look for a DNAME or RRSIG DNAME rdataset.
*/
for (header = node->data; header != NULL; header = header_next) {
header_next = header->next;
if (check_stale_header(node, header, &nlocktype, nlock, search,
&header_prev))
{
/* Do nothing. */
} else if (header->type == dns_rdatatype_dname &&
EXISTS(header) && !ANCIENT(header))
{
dname_header = header;
header_prev = header;
} else if (header->type == DNS_SIGTYPE(dns_rdatatype_dname) &&
EXISTS(header) && !ANCIENT(header))
{
sigdname_header = header;
header_prev = header;
} else {
header_prev = header;
}
}
if (dname_header != NULL &&
(!DNS_TRUST_PENDING(dname_header->trust) ||
(search->options & DNS_DBFIND_PENDINGOK) != 0))
{
/*
* We increment the reference count on node to ensure that
* search->zonecut_header will still be valid later.
*/
qpcnode_acquire(search->qpdb, node, nlocktype,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
search->zonecut = node;
search->zonecut_header = dname_header;
search->zonecut_sigheader = sigdname_header;
search->need_cleanup = true;
result = DNS_R_PARTIALMATCH;
} else {
result = DNS_R_CONTINUE;
}
NODE_UNLOCK(nlock, &nlocktype);
return result;
}
static isc_result_t
find_deepest_zonecut(qpc_search_t *search, qpcnode_t *node,
dns_dbnode_t **nodep, dns_name_t *foundname,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
isc_result_t result = ISC_R_NOTFOUND;
qpcache_t *qpdb = NULL;
/*
* Caller must be holding the tree lock.
*/
qpdb = search->qpdb;
for (int i = dns_qpchain_length(&search->chain) - 1; i >= 0; i--) {
dns_slabheader_t *header = NULL;
dns_slabheader_t *header_prev = NULL, *header_next = NULL;
dns_slabheader_t *found = NULL, *foundsig = NULL;
isc_rwlock_t *nlock = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
dns_qpchain_node(&search->chain, i, NULL, (void **)&node, NULL);
nlock = &qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
/*
* Look for NS and RRSIG NS rdatasets.
*/
for (header = node->data; header != NULL; header = header_next)
{
header_next = header->next;
if (check_stale_header(node, header, &nlocktype, nlock,
search, &header_prev))
{
/* Do nothing. */
} else if (EXISTS(header) && !ANCIENT(header)) {
/*
* We've found an extant rdataset. See if
* we're interested in it.
*/
if (header->type == dns_rdatatype_ns) {
found = header;
if (foundsig != NULL) {
break;
}
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_ns))
{
foundsig = header;
if (found != NULL) {
break;
}
}
header_prev = header;
} else {
header_prev = header;
}
}
if (found != NULL) {
/*
* If we have to set foundname, we do it before
* anything else.
*/
if (foundname != NULL) {
dns_name_copy(&node->name, foundname);
}
result = DNS_R_DELEGATION;
if (nodep != NULL) {
qpcnode_acquire(
search->qpdb, node, nlocktype,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
*nodep = node;
}
bindrdataset(search->qpdb, node, found, search->now,
nlocktype, isc_rwlocktype_none,
rdataset DNS__DB_FLARG_PASS);
if (foundsig != NULL) {
bindrdataset(search->qpdb, node, foundsig,
search->now, nlocktype,
isc_rwlocktype_none,
sigrdataset DNS__DB_FLARG_PASS);
}
if (need_headerupdate(found, search->now) ||
(foundsig != NULL &&
need_headerupdate(foundsig, search->now)))
{
if (nlocktype != isc_rwlocktype_write) {
NODE_FORCEUPGRADE(nlock, &nlocktype);
POST(nlocktype);
}
if (need_headerupdate(found, search->now)) {
update_header(search->qpdb, found,
search->now);
}
if (foundsig != NULL &&
need_headerupdate(foundsig, search->now))
{
update_header(search->qpdb, foundsig,
search->now);
}
}
}
NODE_UNLOCK(nlock, &nlocktype);
if (found != NULL) {
break;
}
}
return result;
}
/*
* Look for a potentially covering NSEC in the cache where `name`
* is known not to exist. This uses the auxiliary NSEC tree to find
* the potential NSEC owner. If found, we update 'foundname', 'nodep',
* 'rdataset' and 'sigrdataset', and return DNS_R_COVERINGNSEC.
* Otherwise, return ISC_R_NOTFOUND.
*/
static isc_result_t
find_coveringnsec(qpc_search_t *search, const dns_name_t *name,
dns_dbnode_t **nodep, isc_stdtime_t now,
dns_name_t *foundname, dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
dns_fixedname_t fpredecessor, fixed;
dns_name_t *predecessor = NULL, *fname = NULL;
qpcnode_t *node = NULL;
dns_qpiter_t iter;
isc_result_t result;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = NULL;
dns_typepair_t matchtype, sigmatchtype;
dns_slabheader_t *found = NULL, *foundsig = NULL;
dns_slabheader_t *header = NULL;
dns_slabheader_t *header_next = NULL, *header_prev = NULL;
/*
* Look for the node in the auxilary tree.
*/
result = dns_qp_lookup(search->qpdb->nsec, name, NULL, &iter, NULL,
(void **)&node, NULL);
if (result != DNS_R_PARTIALMATCH) {
return ISC_R_NOTFOUND;
}
fname = dns_fixedname_initname(&fixed);
predecessor = dns_fixedname_initname(&fpredecessor);
matchtype = DNS_TYPEPAIR_VALUE(dns_rdatatype_nsec, 0);
sigmatchtype = DNS_SIGTYPE(dns_rdatatype_nsec);
/*
* Extract predecessor from iterator.
*/
result = dns_qpiter_current(&iter, predecessor, NULL, NULL);
if (result != ISC_R_SUCCESS) {
return ISC_R_NOTFOUND;
}
/*
* Lookup the predecessor in the main tree.
*/
node = NULL;
result = dns_qp_getname(search->qpdb->tree, predecessor, (void **)&node,
NULL);
if (result != ISC_R_SUCCESS) {
return result;
}
dns_name_copy(&node->name, fname);
nlock = &search->qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
for (header = node->data; header != NULL; header = header_next) {
header_next = header->next;
if (check_stale_header(node, header, &nlocktype, nlock, search,
&header_prev))
{
continue;
}
if (NONEXISTENT(header) || DNS_TYPEPAIR_TYPE(header->type) == 0)
{
header_prev = header;
continue;
}
if (header->type == matchtype) {
found = header;
if (foundsig != NULL) {
break;
}
} else if (header->type == sigmatchtype) {
foundsig = header;
if (found != NULL) {
break;
}
}
header_prev = header;
}
if (found != NULL) {
bindrdataset(search->qpdb, node, found, now, nlocktype,
isc_rwlocktype_none, rdataset DNS__DB_FLARG_PASS);
if (foundsig != NULL) {
bindrdataset(search->qpdb, node, foundsig, now,
nlocktype, isc_rwlocktype_none,
sigrdataset DNS__DB_FLARG_PASS);
}
qpcnode_acquire(search->qpdb, node, nlocktype,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
dns_name_copy(fname, foundname);
*nodep = node;
result = DNS_R_COVERINGNSEC;
} else {
result = ISC_R_NOTFOUND;
}
NODE_UNLOCK(nlock, &nlocktype);
return result;
}
static isc_result_t
find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
dns_rdatatype_t type, unsigned int options, isc_stdtime_t now,
dns_dbnode_t **nodep, dns_name_t *foundname, dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
qpcnode_t *node = NULL;
isc_result_t result;
qpc_search_t search;
bool cname_ok = true;
bool found_noqname = false;
bool all_negative = true;
bool empty_node;
isc_rwlock_t *nlock = NULL;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
dns_slabheader_t *header = NULL;
dns_slabheader_t *header_prev = NULL, *header_next = NULL;
dns_slabheader_t *found = NULL, *nsheader = NULL;
dns_slabheader_t *foundsig = NULL, *nssig = NULL, *cnamesig = NULL;
dns_slabheader_t *update = NULL, *updatesig = NULL;
dns_slabheader_t *nsecheader = NULL, *nsecsig = NULL;
dns_typepair_t sigtype, negtype;
UNUSED(version);
REQUIRE(VALID_QPDB((qpcache_t *)db));
REQUIRE(version == NULL);
if (now == 0) {
now = isc_stdtime_now();
}
search = (qpc_search_t){
.qpdb = (qpcache_t *)db,
.options = options,
.now = now,
};
TREE_RDLOCK(&search.qpdb->tree_lock, &tlocktype);
/*
* Search down from the root of the tree.
*/
result = dns_qp_lookup(search.qpdb->tree, name, NULL, NULL,
&search.chain, (void **)&node, NULL);
if (result != ISC_R_NOTFOUND && foundname != NULL) {
dns_name_copy(&node->name, foundname);
}
/*
* Check the QP chain to see if there's a node above us with a
* active DNAME or NS rdatasets.
*
* We're only interested in nodes above QNAME, so if the result
* was success, then we skip the last item in the chain.
*/
unsigned int len = dns_qpchain_length(&search.chain);
if (result == ISC_R_SUCCESS) {
len--;
}
for (unsigned int i = 0; i < len; i++) {
isc_result_t zcresult;
qpcnode_t *encloser = NULL;
dns_qpchain_node(&search.chain, i, NULL, (void **)&encloser,
NULL);
zcresult = check_zonecut(encloser,
(void *)&search DNS__DB_FLARG_PASS);
if (zcresult != DNS_R_CONTINUE) {
result = DNS_R_PARTIALMATCH;
search.chain.len = i - 1;
node = encloser;
if (foundname != NULL) {
dns_name_copy(&node->name, foundname);
}
break;
}
}
if (result == DNS_R_PARTIALMATCH) {
/*
* If we discovered a covering DNAME skip looking for a covering
* NSEC.
*/
if ((search.options & DNS_DBFIND_COVERINGNSEC) != 0 &&
(search.zonecut_header == NULL ||
search.zonecut_header->type != dns_rdatatype_dname))
{
result = find_coveringnsec(
&search, name, nodep, now, foundname, rdataset,
sigrdataset DNS__DB_FLARG_PASS);
if (result == DNS_R_COVERINGNSEC) {
goto tree_exit;
}
}
if (search.zonecut != NULL) {
result = setup_delegation(&search, nodep, rdataset,
sigrdataset,
tlocktype DNS__DB_FLARG_PASS);
goto tree_exit;
} else {
find_ns:
result = find_deepest_zonecut(
&search, node, nodep, foundname, rdataset,
sigrdataset DNS__DB_FLARG_PASS);
goto tree_exit;
}
} else if (result != ISC_R_SUCCESS) {
goto tree_exit;
}
/*
* Certain DNSSEC types are not subject to CNAME matching
* (RFC4035, section 2.5 and RFC3007).
*
* We don't check for RRSIG, because we don't store RRSIG records
* directly.
*/
if (type == dns_rdatatype_key || type == dns_rdatatype_nsec) {
cname_ok = false;
}
/*
* We now go looking for rdata...
*/
nlock = &search.qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
/*
* These pointers need to be reset here in case we did
* 'goto find_ns' from somewhere below.
*/
found = NULL;
foundsig = NULL;
sigtype = DNS_SIGTYPE(type);
negtype = DNS_TYPEPAIR_VALUE(0, type);
nsheader = NULL;
nsecheader = NULL;
nssig = NULL;
nsecsig = NULL;
cnamesig = NULL;
empty_node = true;
header_prev = NULL;
for (header = node->data; header != NULL; header = header_next) {
header_next = header->next;
if (check_stale_header(node, header, &nlocktype, nlock, &search,
&header_prev))
{
/* Do nothing. */
} else if (EXISTS(header) && !ANCIENT(header)) {
/*
* We now know that there is at least one active
* non-stale rdataset at this node.
*/
empty_node = false;
if (header->noqname != NULL &&
header->trust == dns_trust_secure)
{
found_noqname = true;
}
if (!NEGATIVE(header)) {
all_negative = false;
}
/*
* If we found a type we were looking for, remember
* it.
*/
if (header->type == type ||
(type == dns_rdatatype_any &&
DNS_TYPEPAIR_TYPE(header->type) != 0) ||
(cname_ok && header->type == dns_rdatatype_cname))
{
/*
* We've found the answer.
*/
found = header;
if (header->type == dns_rdatatype_cname &&
cname_ok)
{
/*
* If we've already got the
* CNAME RRSIG, use it.
*/
if (cnamesig != NULL) {
foundsig = cnamesig;
} else {
sigtype = DNS_SIGTYPE(
dns_rdatatype_cname);
}
}
} else if (header->type == sigtype) {
/*
* We've found the RRSIG rdataset for our
* target type. Remember it.
*/
foundsig = header;
} else if (header->type == RDATATYPE_NCACHEANY ||
header->type == negtype)
{
/*
* We've found a negative cache entry.
*/
found = header;
} else if (header->type == dns_rdatatype_ns) {
/*
* Remember a NS rdataset even if we're
* not specifically looking for it, because
* we might need it later.
*/
nsheader = header;
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_ns))
{
/*
* If we need the NS rdataset, we'll also
* need its signature.
*/
nssig = header;
} else if (header->type == dns_rdatatype_nsec) {
nsecheader = header;
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_nsec))
{
nsecsig = header;
} else if (cname_ok &&
header->type ==
DNS_SIGTYPE(dns_rdatatype_cname))
{
/*
* If we get a CNAME match, we'll also need
* its signature.
*/
cnamesig = header;
}
header_prev = header;
} else {
header_prev = header;
}
}
if (empty_node) {
/*
* We have an exact match for the name, but there are no
* extant rdatasets. That means that this node doesn't
* meaningfully exist, and that we really have a partial match.
*/
NODE_UNLOCK(nlock, &nlocktype);
if ((search.options & DNS_DBFIND_COVERINGNSEC) != 0) {
result = find_coveringnsec(
&search, name, nodep, now, foundname, rdataset,
sigrdataset DNS__DB_FLARG_PASS);
if (result == DNS_R_COVERINGNSEC) {
goto tree_exit;
}
}
goto find_ns;
}
/*
* If we didn't find what we were looking for...
*/
if (found == NULL ||
(DNS_TRUST_ADDITIONAL(found->trust) &&
((options & DNS_DBFIND_ADDITIONALOK) == 0)) ||
(found->trust == dns_trust_glue &&
((options & DNS_DBFIND_GLUEOK) == 0)) ||
(DNS_TRUST_PENDING(found->trust) &&
((options & DNS_DBFIND_PENDINGOK) == 0)))
{
/*
* Return covering NODATA NSEC record.
*/
if ((search.options & DNS_DBFIND_COVERINGNSEC) != 0 &&
nsecheader != NULL)
{
if (nodep != NULL) {
qpcnode_acquire(search.qpdb, node, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
*nodep = node;
}
bindrdataset(search.qpdb, node, nsecheader, search.now,
nlocktype, tlocktype,
rdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(nsecheader, search.now)) {
update = nsecheader;
}
if (nsecsig != NULL) {
bindrdataset(search.qpdb, node, nsecsig,
search.now, nlocktype, tlocktype,
sigrdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(nsecsig, search.now)) {
updatesig = nsecsig;
}
}
result = DNS_R_COVERINGNSEC;
goto node_exit;
}
/*
* This name was from a wild card. Look for a covering NSEC.
*/
if (found == NULL && (found_noqname || all_negative) &&
(search.options & DNS_DBFIND_COVERINGNSEC) != 0)
{
NODE_UNLOCK(nlock, &nlocktype);
result = find_coveringnsec(
&search, name, nodep, now, foundname, rdataset,
sigrdataset DNS__DB_FLARG_PASS);
if (result == DNS_R_COVERINGNSEC) {
goto tree_exit;
}
goto find_ns;
}
/*
* If there is an NS rdataset at this node, then this is the
* deepest zone cut.
*/
if (nsheader != NULL) {
if (nodep != NULL) {
qpcnode_acquire(search.qpdb, node, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
*nodep = node;
}
bindrdataset(search.qpdb, node, nsheader, search.now,
nlocktype, tlocktype,
rdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(nsheader, search.now)) {
update = nsheader;
}
if (nssig != NULL) {
bindrdataset(search.qpdb, node, nssig,
search.now, nlocktype, tlocktype,
sigrdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(nssig, search.now)) {
updatesig = nssig;
}
}
result = DNS_R_DELEGATION;
goto node_exit;
}
/*
* Go find the deepest zone cut.
*/
NODE_UNLOCK(nlock, &nlocktype);
goto find_ns;
}
/*
* We found what we were looking for, or we found a CNAME.
*/
if (nodep != NULL) {
qpcnode_acquire(search.qpdb, node, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
*nodep = node;
}
if (NEGATIVE(found)) {
/*
* We found a negative cache entry.
*/
if (NXDOMAIN(found)) {
result = DNS_R_NCACHENXDOMAIN;
} else {
result = DNS_R_NCACHENXRRSET;
}
} else if (type != found->type && type != dns_rdatatype_any &&
found->type == dns_rdatatype_cname)
{
/*
* We weren't doing an ANY query and we found a CNAME instead
* of the type we were looking for, so we need to indicate
* that result to the caller.
*/
result = DNS_R_CNAME;
} else {
/*
* An ordinary successful query!
*/
result = ISC_R_SUCCESS;
}
if (type != dns_rdatatype_any || result == DNS_R_NCACHENXDOMAIN ||
result == DNS_R_NCACHENXRRSET)
{
bindrdataset(search.qpdb, node, found, search.now, nlocktype,
tlocktype, rdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(found, search.now)) {
update = found;
}
if (!NEGATIVE(found) && foundsig != NULL) {
bindrdataset(search.qpdb, node, foundsig, search.now,
nlocktype, tlocktype,
sigrdataset DNS__DB_FLARG_PASS);
if (need_headerupdate(foundsig, search.now)) {
updatesig = foundsig;
}
}
}
node_exit:
if ((update != NULL || updatesig != NULL) &&
nlocktype != isc_rwlocktype_write)
{
NODE_FORCEUPGRADE(nlock, &nlocktype);
POST(nlocktype);
}
if (update != NULL && need_headerupdate(update, search.now)) {
update_header(search.qpdb, update, search.now);
}
if (updatesig != NULL && need_headerupdate(updatesig, search.now)) {
update_header(search.qpdb, updatesig, search.now);
}
NODE_UNLOCK(nlock, &nlocktype);
tree_exit:
TREE_UNLOCK(&search.qpdb->tree_lock, &tlocktype);
/*
* If we found a zonecut but aren't going to use it, we have to
* let go of it.
*/
if (search.need_cleanup) {
node = search.zonecut;
INSIST(node != NULL);
nlock = &search.qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
qpcnode_release(search.qpdb, node, &nlocktype, &tlocktype,
true DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
INSIST(tlocktype == isc_rwlocktype_none);
}
update_cachestats(search.qpdb, result);
return result;
}
static isc_result_t
findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
isc_stdtime_t now, dns_dbnode_t **nodep, dns_name_t *foundname,
dns_name_t *dcname, dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
qpcnode_t *node = NULL;
isc_rwlock_t *nlock = NULL;
isc_result_t result;
qpc_search_t search;
dns_slabheader_t *header = NULL;
dns_slabheader_t *header_prev = NULL, *header_next = NULL;
dns_slabheader_t *found = NULL, *foundsig = NULL;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
bool dcnull = (dcname == NULL);
REQUIRE(VALID_QPDB((qpcache_t *)db));
if (now == 0) {
now = isc_stdtime_now();
}
search = (qpc_search_t){
.qpdb = (qpcache_t *)db,
.options = options,
.now = now,
};
if (dcnull) {
dcname = foundname;
}
TREE_RDLOCK(&search.qpdb->tree_lock, &tlocktype);
/*
* Search down from the root of the tree.
*/
result = dns_qp_lookup(search.qpdb->tree, name, NULL, NULL,
&search.chain, (void **)&node, NULL);
if (result != ISC_R_NOTFOUND) {
dns_name_copy(&node->name, dcname);
}
if ((options & DNS_DBFIND_NOEXACT) != 0 && result == ISC_R_SUCCESS) {
int len = dns_qpchain_length(&search.chain);
if (len >= 2) {
node = NULL;
dns_qpchain_node(&search.chain, len - 2, NULL,
(void **)&node, NULL);
search.chain.len = len - 1;
result = DNS_R_PARTIALMATCH;
} else {
result = ISC_R_NOTFOUND;
}
}
if (result == DNS_R_PARTIALMATCH) {
result = find_deepest_zonecut(&search, node, nodep, foundname,
rdataset,
sigrdataset DNS__DB_FLARG_PASS);
goto tree_exit;
} else if (result != ISC_R_SUCCESS) {
goto tree_exit;
} else if (!dcnull) {
dns_name_copy(dcname, foundname);
}
/*
* We now go looking for an NS rdataset at the node.
*/
nlock = &search.qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
for (header = node->data; header != NULL; header = header_next) {
header_next = header->next;
bool ns = (header->type == dns_rdatatype_ns ||
header->type == DNS_SIGTYPE(dns_rdatatype_ns));
if (check_stale_header(node, header, &nlocktype, nlock, &search,
&header_prev))
{
if (ns) {
/*
* We found a cached NS, but was either
* ancient or it was stale and serve-stale
* is disabled, so this node can't be used
* as a zone cut we know about. Instead we
* bail out and call find_deepest_zonecut()
* below.
*/
break;
}
} else if (EXISTS(header) && !ANCIENT(header)) {
if (header->type == dns_rdatatype_ns) {
found = header;
if (foundsig != NULL) {
break;
}
} else if (header->type ==
DNS_SIGTYPE(dns_rdatatype_ns))
{
foundsig = header;
if (found != NULL) {
break;
}
}
header_prev = header;
} else {
header_prev = header;
}
}
if (found == NULL) {
/*
* No active NS records found. Call find_deepest_zonecut()
* to look for them in nodes above this one.
*/
NODE_UNLOCK(nlock, &nlocktype);
result = find_deepest_zonecut(&search, node, nodep, foundname,
rdataset,
sigrdataset DNS__DB_FLARG_PASS);
dns_name_copy(foundname, dcname);
goto tree_exit;
}
if (nodep != NULL) {
qpcnode_acquire(search.qpdb, node, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
*nodep = node;
}
bindrdataset(search.qpdb, node, found, search.now, nlocktype, tlocktype,
rdataset DNS__DB_FLARG_PASS);
if (foundsig != NULL) {
bindrdataset(search.qpdb, node, foundsig, search.now, nlocktype,
tlocktype, sigrdataset DNS__DB_FLARG_PASS);
}
if (need_headerupdate(found, search.now) ||
(foundsig != NULL && need_headerupdate(foundsig, search.now)))
{
if (nlocktype != isc_rwlocktype_write) {
NODE_FORCEUPGRADE(nlock, &nlocktype);
POST(nlocktype);
}
if (need_headerupdate(found, search.now)) {
update_header(search.qpdb, found, search.now);
}
if (foundsig != NULL && need_headerupdate(foundsig, search.now))
{
update_header(search.qpdb, foundsig, search.now);
}
}
NODE_UNLOCK(nlock, &nlocktype);
tree_exit:
TREE_UNLOCK(&search.qpdb->tree_lock, &tlocktype);
INSIST(!search.need_cleanup);
if (result == DNS_R_DELEGATION) {
result = ISC_R_SUCCESS;
}
return result;
}
static isc_result_t
findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
dns_rdatatype_t type, dns_rdatatype_t covers, isc_stdtime_t now,
dns_rdataset_t *rdataset,
dns_rdataset_t *sigrdataset DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
dns_slabheader_t *header = NULL, *header_next = NULL;
dns_slabheader_t *found = NULL, *foundsig = NULL;
dns_typepair_t matchtype, sigmatchtype, negtype;
isc_result_t result;
isc_rwlock_t *nlock = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
REQUIRE(VALID_QPDB(qpdb));
REQUIRE(type != dns_rdatatype_any);
UNUSED(version);
result = ISC_R_SUCCESS;
if (now == 0) {
now = isc_stdtime_now();
}
nlock = &qpdb->buckets[qpnode->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
matchtype = DNS_TYPEPAIR_VALUE(type, covers);
negtype = DNS_TYPEPAIR_VALUE(0, type);
if (covers == 0) {
sigmatchtype = DNS_SIGTYPE(type);
} else {
sigmatchtype = 0;
}
for (header = qpnode->data; header != NULL; header = header_next) {
header_next = header->next;
if (!ACTIVE(header, now)) {
if ((header->ttl + STALE_TTL(header, qpdb) <
now - QPDB_VIRTUAL) &&
(nlocktype == isc_rwlocktype_write ||
NODE_TRYUPGRADE(nlock, &nlocktype) ==
ISC_R_SUCCESS))
{
/*
* We update the node's status only when we
* can get write access.
*
* We don't check if refcurrent(qpnode) == 0
* and try to free like we do in find(),
* because refcurrent(qpnode) must be
* non-zero. This is so because 'node' is an
* argument to the function.
*/
mark_ancient(header);
}
} else if (EXISTS(header) && !ANCIENT(header)) {
if (header->type == matchtype) {
found = header;
} else if (header->type == RDATATYPE_NCACHEANY ||
header->type == negtype)
{
found = header;
} else if (header->type == sigmatchtype) {
foundsig = header;
}
}
}
if (found != NULL) {
bindrdataset(qpdb, qpnode, found, now, nlocktype,
isc_rwlocktype_none, rdataset DNS__DB_FLARG_PASS);
if (!NEGATIVE(found) && foundsig != NULL) {
bindrdataset(qpdb, qpnode, foundsig, now, nlocktype,
isc_rwlocktype_none,
sigrdataset DNS__DB_FLARG_PASS);
}
}
NODE_UNLOCK(nlock, &nlocktype);
if (found == NULL) {
return ISC_R_NOTFOUND;
}
if (NEGATIVE(found)) {
/*
* We found a negative cache entry.
*/
if (NXDOMAIN(found)) {
result = DNS_R_NCACHENXDOMAIN;
} else {
result = DNS_R_NCACHENXRRSET;
}
}
update_cachestats(qpdb, result);
return result;
}
static isc_result_t
setcachestats(dns_db_t *db, isc_stats_t *stats) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
REQUIRE(stats != NULL);
isc_stats_attach(stats, &qpdb->cachestats);
return ISC_R_SUCCESS;
}
static dns_stats_t *
getrrsetstats(dns_db_t *db) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
return qpdb->rrsetstats;
}
static isc_result_t
setservestalettl(dns_db_t *db, dns_ttl_t ttl) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
/* currently no bounds checking. 0 means disable. */
qpdb->common.serve_stale_ttl = ttl;
return ISC_R_SUCCESS;
}
static isc_result_t
getservestalettl(dns_db_t *db, dns_ttl_t *ttl) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
*ttl = qpdb->common.serve_stale_ttl;
return ISC_R_SUCCESS;
}
static isc_result_t
setservestalerefresh(dns_db_t *db, uint32_t interval) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
/* currently no bounds checking. 0 means disable. */
qpdb->serve_stale_refresh = interval;
return ISC_R_SUCCESS;
}
static isc_result_t
getservestalerefresh(dns_db_t *db, uint32_t *interval) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
*interval = qpdb->serve_stale_refresh;
return ISC_R_SUCCESS;
}
static void
expiredata(dns_db_t *db, dns_dbnode_t *node, void *data) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
dns_slabheader_t *header = data;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[qpnode->locknum].lock;
NODE_WRLOCK(nlock, &nlocktype);
expireheader(header, &nlocktype, &tlocktype,
dns_expire_flush DNS__DB_FILELINE);
NODE_UNLOCK(nlock, &nlocktype);
INSIST(tlocktype == isc_rwlocktype_none);
}
static size_t
rdataset_size(dns_slabheader_t *header) {
if (!NONEXISTENT(header)) {
return dns_rdataslab_size((unsigned char *)header,
sizeof(*header));
}
return sizeof(*header);
}
static size_t
expire_lru_headers(qpcache_t *qpdb, unsigned int locknum,
isc_rwlocktype_t *nlocktypep, isc_rwlocktype_t *tlocktypep,
size_t purgesize DNS__DB_FLARG) {
dns_slabheader_t *header = NULL;
size_t purged = 0;
for (header = ISC_LIST_TAIL(qpdb->buckets[locknum].lru);
header != NULL && header->last_used <= qpdb->last_used &&
purged <= purgesize;
header = ISC_LIST_TAIL(qpdb->buckets[locknum].lru))
{
size_t header_size = rdataset_size(header);
/*
* Unlink the entry at this point to avoid checking it
* again even if it's currently used someone else and
* cannot be purged at this moment. This entry won't be
* referenced any more (so unlinking is safe) since the
* TTL will be reset to 0.
*/
ISC_LIST_UNLINK(qpdb->buckets[locknum].lru, header, link);
expireheader(header, nlocktypep, tlocktypep,
dns_expire_lru DNS__DB_FLARG_PASS);
purged += header_size;
}
return purged;
}
/*%
* Purge some expired and/or stale (i.e. unused for some period) cache entries
* due to an overmem condition. To recover from this condition quickly,
* we clean up entries up to the size of newly added rdata that triggered
* the overmem; this is accessible via newheader.
*
* The LRU lists tails are processed in LRU order to the nearest second.
*
* A write lock on the tree must be held.
*/
static void
overmem(qpcache_t *qpdb, dns_slabheader_t *newheader,
isc_rwlocktype_t *tlocktypep DNS__DB_FLARG) {
uint32_t locknum_start = qpdb->lru_sweep++ % qpdb->buckets_count;
uint32_t locknum = locknum_start;
size_t purgesize, purged = 0;
isc_stdtime_t min_last_used = 0;
size_t max_passes = 8;
/*
* Maximum estimated size of the data being added: The size
* of the rdataset, plus a new QP database node and nodename,
* and a possible additional NSEC node and nodename. Also add
* a 12k margin for a possible QP-trie chunk allocation.
* (It's okay to overestimate, we want to get cache memory
* down quickly.)
*/
purgesize = 2 * (sizeof(qpcnode_t) +
dns_name_size(&HEADERNODE(newheader)->name)) +
rdataset_size(newheader) + 12288;
again:
do {
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[locknum].lock;
NODE_WRLOCK(nlock, &nlocktype);
purged += expire_lru_headers(
qpdb, locknum, &nlocktype, tlocktypep,
purgesize - purged DNS__DB_FLARG_PASS);
/*
* Work out the oldest remaining last_used values of the list
* tails as we walk across the array of lru lists.
*/
dns_slabheader_t *header =
ISC_LIST_TAIL(qpdb->buckets[locknum].lru);
if (header != NULL &&
(min_last_used == 0 || header->last_used < min_last_used))
{
min_last_used = header->last_used;
}
NODE_UNLOCK(nlock, &nlocktype);
locknum = (locknum + 1) % qpdb->buckets_count;
} while (locknum != locknum_start && purged <= purgesize);
/*
* Update qpdb->last_used if we have walked all the list tails and have
* not freed the required amount of memory.
*/
if (purged < purgesize) {
if (min_last_used != 0) {
qpdb->last_used = min_last_used;
if (max_passes-- > 0) {
goto again;
}
}
}
}
/*%
* These functions allow the heap code to rank the priority of each
* element. It returns true if v1 happens "sooner" than v2.
*/
static bool
ttl_sooner(void *v1, void *v2) {
dns_slabheader_t *h1 = v1;
dns_slabheader_t *h2 = v2;
return h1->ttl < h2->ttl;
}
/*%
* This function sets the heap index into the header.
*/
static void
set_index(void *what, unsigned int idx) {
dns_slabheader_t *h = what;
h->heap_index = idx;
}
static void
qpcache__destroy(qpcache_t *qpdb) {
unsigned int i;
char buf[DNS_NAME_FORMATSIZE];
dns_qp_t **treep = NULL;
for (;;) {
/*
* pick the next tree to (start to) destroy
*/
treep = &qpdb->tree;
if (*treep == NULL) {
treep = &qpdb->nsec;
if (*treep == NULL) {
break;
}
}
dns_qp_destroy(treep);
INSIST(*treep == NULL);
}
if (dns_name_dynamic(&qpdb->common.origin)) {
dns_name_format(&qpdb->common.origin, buf, sizeof(buf));
} else {
strlcpy(buf, "<UNKNOWN>", sizeof(buf));
}
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_CACHE,
ISC_LOG_DEBUG(1), "done %s(%s)", __func__, buf);
if (dns_name_dynamic(&qpdb->common.origin)) {
dns_name_free(&qpdb->common.origin, qpdb->common.mctx);
}
for (i = 0; i < qpdb->buckets_count; i++) {
NODE_DESTROYLOCK(&qpdb->buckets[i].lock);
INSIST(ISC_LIST_EMPTY(qpdb->buckets[i].lru));
INSIST(isc_queue_empty(&qpdb->buckets[i].deadnodes));
isc_queue_destroy(&qpdb->buckets[i].deadnodes);
isc_heap_destroy(&qpdb->buckets[i].heap);
}
if (qpdb->rrsetstats != NULL) {
dns_stats_detach(&qpdb->rrsetstats);
}
if (qpdb->cachestats != NULL) {
isc_stats_detach(&qpdb->cachestats);
}
TREE_DESTROYLOCK(&qpdb->tree_lock);
isc_refcount_destroy(&qpdb->references);
isc_refcount_destroy(&qpdb->common.references);
isc_rwlock_destroy(&qpdb->lock);
qpdb->common.magic = 0;
qpdb->common.impmagic = 0;
isc_mem_detach(&qpdb->hmctx);
isc_mem_putanddetach(&qpdb->common.mctx, qpdb,
sizeof(*qpdb) + qpdb->buckets_count *
sizeof(qpdb->buckets[0]));
}
static void
qpdb_destroy(dns_db_t *arg) {
qpcache_t *qpdb = (qpcache_t *)arg;
qpcache_detach(&qpdb);
}
/*%
* Clean up dead nodes. These are nodes which have no references, and
* have no data. They are dead but we could not or chose not to delete
* them when we deleted all the data at that node because we did not want
* to wait for the tree write lock.
*/
static void
cleanup_deadnodes(void *arg) {
qpcache_t *qpdb = arg;
uint16_t locknum = isc_tid();
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[locknum].lock;
qpcnode_t *qpnode = NULL, *qpnext = NULL;
isc_queue_t deadnodes;
INSIST(locknum < qpdb->buckets_count);
isc_queue_init(&deadnodes);
TREE_WRLOCK(&qpdb->tree_lock, &tlocktype);
NODE_WRLOCK(nlock, &nlocktype);
RUNTIME_CHECK(isc_queue_splice(&deadnodes,
&qpdb->buckets[locknum].deadnodes));
isc_queue_for_each_entry_safe(&deadnodes, qpnode, qpnext, deadlink) {
qpcnode_release(qpdb, qpnode, &nlocktype, &tlocktype,
false DNS__DB_FILELINE);
}
NODE_UNLOCK(nlock, &nlocktype);
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
}
/*
* This function is assumed to be called when a node is newly referenced
* and can be in the deadnode list. In that case the node will be references
* and cleanup_deadnodes() will remove it from the list when the cleaning
* happens.
* Note: while a new reference is gained in multiple places, there are only very
* few cases where the node can be in the deadnode list (only empty nodes can
* have been added to the list).
*/
static void
reactivate_node(qpcache_t *qpdb, qpcnode_t *node,
isc_rwlocktype_t tlocktype ISC_ATTR_UNUSED DNS__DB_FLARG) {
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
qpcnode_acquire(qpdb, node, nlocktype, tlocktype DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
}
static qpcnode_t *
new_qpcnode(qpcache_t *qpdb, const dns_name_t *name) {
qpcnode_t *newdata = isc_mem_get(qpdb->common.mctx, sizeof(*newdata));
*newdata = (qpcnode_t){
.name = DNS_NAME_INITEMPTY,
.references = ISC_REFCOUNT_INITIALIZER(1),
.locknum = isc_random_uniform(qpdb->buckets_count),
};
isc_mem_attach(qpdb->common.mctx, &newdata->mctx);
dns_name_dupwithoffsets(name, newdata->mctx, &newdata->name);
#ifdef DNS_DB_NODETRACE
fprintf(stderr, "new_qpcnode:%s:%s:%d:%p->references = 1\n", __func__,
__FILE__, __LINE__ + 1, name);
#endif
return newdata;
}
static isc_result_t
findnode(dns_db_t *db, const dns_name_t *name, bool create,
dns_dbnode_t **nodep DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *node = NULL;
isc_result_t result;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
TREE_RDLOCK(&qpdb->tree_lock, &tlocktype);
result = dns_qp_getname(qpdb->tree, name, (void **)&node, NULL);
if (result != ISC_R_SUCCESS) {
if (!create) {
goto unlock;
}
/*
* Try to upgrade the lock and if that fails unlock then relock.
*/
TREE_FORCEUPGRADE(&qpdb->tree_lock, &tlocktype);
result = dns_qp_getname(qpdb->tree, name, (void **)&node, NULL);
if (result != ISC_R_SUCCESS) {
node = new_qpcnode(qpdb, name);
result = dns_qp_insert(qpdb->tree, node, 0);
INSIST(result == ISC_R_SUCCESS);
qpcnode_unref(node);
}
}
reactivate_node(qpdb, node, tlocktype DNS__DB_FLARG_PASS);
*nodep = (dns_dbnode_t *)node;
unlock:
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
return result;
}
static void
attachnode(dns_db_t *db, dns_dbnode_t *source,
dns_dbnode_t **targetp DNS__DB_FLARG) {
REQUIRE(VALID_QPDB((qpcache_t *)db));
REQUIRE(targetp != NULL && *targetp == NULL);
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *node = (qpcnode_t *)source;
qpcnode_acquire(qpdb, node, isc_rwlocktype_none,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
*targetp = source;
}
static void
detachnode(dns_db_t *db, dns_dbnode_t **nodep DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *node = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = NULL;
REQUIRE(VALID_QPDB(qpdb));
REQUIRE(nodep != NULL && *nodep != NULL);
node = (qpcnode_t *)(*nodep);
*nodep = NULL;
nlock = &qpdb->buckets[node->locknum].lock;
/*
* We can't destroy qpcache while holding a nodelock, so we need to
* reference it before acquiring the lock and release it afterward.
* Additionally, we must ensure that we don't destroy the database while
* the NODE_LOCK is locked.
*/
qpcache_ref(qpdb);
rcu_read_lock();
NODE_RDLOCK(nlock, &nlocktype);
qpcnode_release(qpdb, node, &nlocktype, &tlocktype,
true DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
rcu_read_unlock();
qpcache_detach(&qpdb);
}
static isc_result_t
createiterator(dns_db_t *db, unsigned int options ISC_ATTR_UNUSED,
dns_dbiterator_t **iteratorp) {
qpcache_t *qpdb = (qpcache_t *)db;
qpc_dbit_t *qpdbiter = NULL;
REQUIRE(VALID_QPDB(qpdb));
qpdbiter = isc_mem_get(qpdb->common.mctx, sizeof(*qpdbiter));
*qpdbiter = (qpc_dbit_t){
.common.methods = &dbiterator_methods,
.common.magic = DNS_DBITERATOR_MAGIC,
.paused = true,
};
qpdbiter->name = dns_fixedname_initname(&qpdbiter->fixed);
dns_db_attach(db, &qpdbiter->common.db);
dns_qpiter_init(qpdb->tree, &qpdbiter->iter);
*iteratorp = (dns_dbiterator_t *)qpdbiter;
return ISC_R_SUCCESS;
}
static isc_result_t
allrdatasets(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
unsigned int options, isc_stdtime_t now,
dns_rdatasetiter_t **iteratorp DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
qpc_rditer_t *iterator = NULL;
REQUIRE(VALID_QPDB(qpdb));
UNUSED(version);
iterator = isc_mem_get(qpdb->common.mctx, sizeof(*iterator));
if (now == 0) {
now = isc_stdtime_now();
}
iterator->common.magic = DNS_RDATASETITER_MAGIC;
iterator->common.methods = &rdatasetiter_methods;
iterator->common.db = db;
iterator->common.node = node;
iterator->common.version = NULL;
iterator->common.options = options;
iterator->common.now = now;
iterator->current = NULL;
qpcnode_acquire(qpdb, qpnode, isc_rwlocktype_none,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
*iteratorp = (dns_rdatasetiter_t *)iterator;
return ISC_R_SUCCESS;
}
static bool
overmaxtype(qpcache_t *qpdb, uint32_t ntypes) {
if (qpdb->maxtypepername == 0) {
return false;
}
return ntypes >= qpdb->maxtypepername;
}
static bool
prio_header(dns_slabheader_t *header) {
if (NEGATIVE(header) && prio_type(DNS_TYPEPAIR_COVERS(header->type))) {
return true;
}
return prio_type(header->type);
}
static isc_result_t
add(qpcache_t *qpdb, qpcnode_t *qpnode,
const dns_name_t *nodename ISC_ATTR_UNUSED, dns_slabheader_t *newheader,
unsigned int options, bool loading, dns_rdataset_t *addedrdataset,
isc_stdtime_t now, isc_rwlocktype_t nlocktype,
isc_rwlocktype_t tlocktype DNS__DB_FLARG) {
dns_slabheader_t *topheader = NULL, *topheader_prev = NULL;
dns_slabheader_t *header = NULL, *sigheader = NULL;
dns_slabheader_t *prioheader = NULL, *expireheader = NULL;
bool header_nx;
bool newheader_nx;
dns_typepair_t negtype = 0;
dns_trust_t trust;
int idx;
uint32_t ntypes = 0;
if ((options & DNS_DBADD_FORCE) != 0) {
trust = dns_trust_ultimate;
} else {
trust = newheader->trust;
}
newheader_nx = NONEXISTENT(newheader) ? true : false;
if (!newheader_nx) {
dns_rdatatype_t rdtype = DNS_TYPEPAIR_TYPE(newheader->type);
dns_rdatatype_t covers = DNS_TYPEPAIR_COVERS(newheader->type);
dns_typepair_t sigtype = DNS_SIGTYPE(covers);
if (NEGATIVE(newheader)) {
/*
* We're adding a negative cache entry.
*/
if (covers == dns_rdatatype_any) {
/*
* If we're adding an negative cache entry
* which covers all types (NXDOMAIN,
* NODATA(QTYPE=ANY)),
*
* We make all other data ancient so that the
* only rdataset that can be found at this
* node is the negative cache entry.
*/
for (topheader = qpnode->data;
topheader != NULL;
topheader = topheader->next)
{
mark_ancient(topheader);
}
goto find_header;
}
/*
* Otherwise look for any RRSIGs of the given
* type so they can be marked ancient later.
*/
for (topheader = qpnode->data; topheader != NULL;
topheader = topheader->next)
{
if (topheader->type == sigtype) {
sigheader = topheader;
break;
}
}
negtype = DNS_TYPEPAIR_VALUE(covers, 0);
} else {
/*
* We're adding something that isn't a
* negative cache entry. Look for an extant
* non-ancient NXDOMAIN/NODATA(QTYPE=ANY) negative
* cache entry. If we're adding an RRSIG, also
* check for an extant non-ancient NODATA ncache
* entry which covers the same type as the RRSIG.
*/
for (topheader = qpnode->data; topheader != NULL;
topheader = topheader->next)
{
if ((topheader->type == RDATATYPE_NCACHEANY) ||
(newheader->type == sigtype &&
topheader->type ==
DNS_TYPEPAIR_VALUE(0, covers)))
{
break;
}
}
if (topheader != NULL && EXISTS(topheader) &&
ACTIVE(topheader, now))
{
/*
* Found one.
*/
if (trust < topheader->trust) {
/*
* The NXDOMAIN/NODATA(QTYPE=ANY)
* is more trusted.
*/
dns_slabheader_destroy(&newheader);
if (addedrdataset != NULL) {
bindrdataset(
qpdb, qpnode, topheader,
now, nlocktype,
tlocktype,
addedrdataset
DNS__DB_FLARG_PASS);
}
return DNS_R_UNCHANGED;
}
/*
* The new rdataset is better. Expire the
* ncache entry.
*/
mark_ancient(topheader);
topheader = NULL;
goto find_header;
}
negtype = DNS_TYPEPAIR_VALUE(0, rdtype);
}
}
for (topheader = qpnode->data; topheader != NULL;
topheader = topheader->next)
{
if (ACTIVE(topheader, now)) {
++ntypes;
expireheader = topheader;
}
if (prio_header(topheader)) {
prioheader = topheader;
}
if (topheader->type == newheader->type ||
topheader->type == negtype)
{
break;
}
topheader_prev = topheader;
}
find_header:
/*
* If header isn't NULL, we've found the right type. There may be
* IGNORE rdatasets between the top of the chain and the first real
* data. We skip over them.
*/
header = topheader;
while (header != NULL && IGNORE(header)) {
header = header->down;
}
if (header != NULL) {
header_nx = NONEXISTENT(header) ? true : false;
/*
* Deleting an already non-existent rdataset has no effect.
*/
if (header_nx && newheader_nx) {
dns_slabheader_destroy(&newheader);
return DNS_R_UNCHANGED;
}
/*
* Trying to add an rdataset with lower trust to a cache
* DB has no effect, provided that the cache data isn't
* stale. If the cache data is stale, new lower trust
* data will supersede it below. Unclear what the best
* policy is here.
*/
if (trust < header->trust && (ACTIVE(header, now) || header_nx))
{
dns_slabheader_destroy(&newheader);
if (addedrdataset != NULL) {
bindrdataset(qpdb, qpnode, header, now,
nlocktype, tlocktype,
addedrdataset DNS__DB_FLARG_PASS);
}
return DNS_R_UNCHANGED;
}
/*
* Don't replace existing NS, A and AAAA RRsets in the
* cache if they are already exist. This prevents named
* being locked to old servers. Don't lower trust of
* existing record if the update is forced. Nothing
* special to be done w.r.t stale data; it gets replaced
* normally further down.
*/
if (ACTIVE(header, now) && header->type == dns_rdatatype_ns &&
!header_nx && !newheader_nx &&
header->trust >= newheader->trust &&
dns_rdataslab_equalx((unsigned char *)header,
(unsigned char *)newheader,
(unsigned int)(sizeof(*newheader)),
qpdb->common.rdclass,
(dns_rdatatype_t)header->type))
{
/*
* Honour the new ttl if it is less than the
* older one.
*/
if (header->ttl > newheader->ttl) {
setttl(header, newheader->ttl);
}
if (header->last_used != now) {
ISC_LIST_UNLINK(
qpdb->buckets[HEADERNODE(header)->locknum]
.lru,
header, link);
header->last_used = now;
ISC_LIST_PREPEND(
qpdb->buckets[HEADERNODE(header)->locknum]
.lru,
header, link);
}
if (header->noqname == NULL &&
newheader->noqname != NULL)
{
header->noqname = newheader->noqname;
newheader->noqname = NULL;
}
if (header->closest == NULL &&
newheader->closest != NULL)
{
header->closest = newheader->closest;
newheader->closest = NULL;
}
dns_slabheader_destroy(&newheader);
if (addedrdataset != NULL) {
bindrdataset(qpdb, qpnode, header, now,
nlocktype, tlocktype,
addedrdataset DNS__DB_FLARG_PASS);
}
return ISC_R_SUCCESS;
}
/*
* If we have will be replacing a NS RRset force its TTL
* to be no more than the current NS RRset's TTL. This
* ensures the delegations that are withdrawn are honoured.
*/
if (ACTIVE(header, now) && header->type == dns_rdatatype_ns &&
!header_nx && !newheader_nx &&
header->trust <= newheader->trust)
{
if (newheader->ttl > header->ttl) {
newheader->ttl = header->ttl;
}
}
if (ACTIVE(header, now) &&
(options & DNS_DBADD_PREFETCH) == 0 &&
(header->type == dns_rdatatype_a ||
header->type == dns_rdatatype_aaaa ||
header->type == dns_rdatatype_ds ||
header->type == DNS_SIGTYPE(dns_rdatatype_ds)) &&
!header_nx && !newheader_nx &&
header->trust >= newheader->trust &&
dns_rdataslab_equal((unsigned char *)header,
(unsigned char *)newheader,
(unsigned int)(sizeof(*newheader))))
{
/*
* Honour the new ttl if it is less than the
* older one.
*/
if (header->ttl > newheader->ttl) {
setttl(header, newheader->ttl);
}
if (header->last_used != now) {
ISC_LIST_UNLINK(
qpdb->buckets[HEADERNODE(header)->locknum]
.lru,
header, link);
header->last_used = now;
ISC_LIST_PREPEND(
qpdb->buckets[HEADERNODE(header)->locknum]
.lru,
header, link);
}
if (header->noqname == NULL &&
newheader->noqname != NULL)
{
header->noqname = newheader->noqname;
newheader->noqname = NULL;
}
if (header->closest == NULL &&
newheader->closest != NULL)
{
header->closest = newheader->closest;
newheader->closest = NULL;
}
dns_slabheader_destroy(&newheader);
if (addedrdataset != NULL) {
bindrdataset(qpdb, qpnode, header, now,
nlocktype, tlocktype,
addedrdataset DNS__DB_FLARG_PASS);
}
return ISC_R_SUCCESS;
}
if (loading) {
newheader->down = NULL;
idx = HEADERNODE(newheader)->locknum;
if (ZEROTTL(newheader)) {
newheader->last_used = qpdb->last_used + 1;
ISC_LIST_APPEND(qpdb->buckets[idx].lru,
newheader, link);
} else {
ISC_LIST_PREPEND(qpdb->buckets[idx].lru,
newheader, link);
}
isc_heap_insert(qpdb->buckets[idx].heap, newheader);
newheader->heap = qpdb->buckets[idx].heap;
/*
* There are no other references to 'header' when
* loading, so we MAY clean up 'header' now.
* Since we don't generate changed records when
* loading, we MUST clean up 'header' now.
*/
if (topheader_prev != NULL) {
topheader_prev->next = newheader;
} else {
qpnode->data = newheader;
}
newheader->next = topheader->next;
dns_slabheader_destroy(&header);
} else {
idx = HEADERNODE(newheader)->locknum;
isc_heap_insert(qpdb->buckets[idx].heap, newheader);
newheader->heap = qpdb->buckets[idx].heap;
if (ZEROTTL(newheader)) {
newheader->last_used = qpdb->last_used + 1;
ISC_LIST_APPEND(qpdb->buckets[idx].lru,
newheader, link);
} else {
ISC_LIST_PREPEND(qpdb->buckets[idx].lru,
newheader, link);
}
if (topheader_prev != NULL) {
topheader_prev->next = newheader;
} else {
qpnode->data = newheader;
}
newheader->next = topheader->next;
newheader->down = topheader;
topheader->next = newheader;
mark_ancient(header);
if (sigheader != NULL) {
mark_ancient(sigheader);
}
}
} else {
/*
* No non-IGNORED rdatasets of the given type exist at
* this node.
*/
/*
* If we're trying to delete the type, don't bother.
*/
if (newheader_nx) {
dns_slabheader_destroy(&newheader);
return DNS_R_UNCHANGED;
}
idx = HEADERNODE(newheader)->locknum;
isc_heap_insert(qpdb->buckets[idx].heap, newheader);
newheader->heap = qpdb->buckets[idx].heap;
if (ZEROTTL(newheader)) {
ISC_LIST_APPEND(qpdb->buckets[idx].lru, newheader,
link);
} else {
ISC_LIST_PREPEND(qpdb->buckets[idx].lru, newheader,
link);
}
if (topheader != NULL) {
/*
* We have a list of rdatasets of the given type,
* but they're all marked IGNORE. We simply insert
* the new rdataset at the head of the list.
*
* Ignored rdatasets cannot occur during loading, so
* we INSIST on it.
*/
INSIST(!loading);
if (topheader_prev != NULL) {
topheader_prev->next = newheader;
} else {
qpnode->data = newheader;
}
newheader->next = topheader->next;
newheader->down = topheader;
topheader->next = newheader;
qpnode->dirty = 1;
} else {
/*
* No rdatasets of the given type exist at the node.
*/
INSIST(newheader->down == NULL);
if (prio_header(newheader)) {
/* This is a priority type, prepend it */
newheader->next = qpnode->data;
qpnode->data = newheader;
} else if (prioheader != NULL) {
/* Append after the priority headers */
newheader->next = prioheader->next;
prioheader->next = newheader;
} else {
/* There were no priority headers */
newheader->next = qpnode->data;
qpnode->data = newheader;
}
if (overmaxtype(qpdb, ntypes)) {
if (expireheader == NULL) {
expireheader = newheader;
}
if (NEGATIVE(newheader) &&
!prio_header(newheader))
{
/*
* Add the new non-priority negative
* header to the database only
* temporarily.
*/
expireheader = newheader;
}
mark_ancient(expireheader);
/*
* FIXME: In theory, we should mark the RRSIG
* and the header at the same time, but there is
* no direct link between those two header, so
* we would have to check the whole list again.
*/
}
}
}
if (addedrdataset != NULL) {
bindrdataset(qpdb, qpnode, newheader, now, nlocktype, tlocktype,
addedrdataset DNS__DB_FLARG_PASS);
}
return ISC_R_SUCCESS;
}
static isc_result_t
addnoqname(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
dns_rdataset_t *rdataset) {
isc_result_t result;
dns_slabheader_proof_t *noqname = NULL;
dns_name_t name = DNS_NAME_INITEMPTY;
dns_rdataset_t neg = DNS_RDATASET_INIT, negsig = DNS_RDATASET_INIT;
isc_region_t r1, r2;
result = dns_rdataset_getnoqname(rdataset, &name, &neg, &negsig);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
noqname = isc_mem_get(mctx, sizeof(*noqname));
*noqname = (dns_slabheader_proof_t){
.neg = r1.base,
.negsig = r2.base,
.type = neg.type,
.name = DNS_NAME_INITEMPTY,
};
dns_name_dup(&name, mctx, &noqname->name);
newheader->noqname = noqname;
cleanup:
dns_rdataset_disassociate(&neg);
dns_rdataset_disassociate(&negsig);
return result;
}
static isc_result_t
addclosest(isc_mem_t *mctx, dns_slabheader_t *newheader, uint32_t maxrrperset,
dns_rdataset_t *rdataset) {
isc_result_t result;
dns_slabheader_proof_t *closest = NULL;
dns_name_t name = DNS_NAME_INITEMPTY;
dns_rdataset_t neg = DNS_RDATASET_INIT, negsig = DNS_RDATASET_INIT;
isc_region_t r1, r2;
result = dns_rdataset_getclosest(rdataset, &name, &neg, &negsig);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
result = dns_rdataslab_fromrdataset(&neg, mctx, &r1, 0, maxrrperset);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
result = dns_rdataslab_fromrdataset(&negsig, mctx, &r2, 0, maxrrperset);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
closest = isc_mem_get(mctx, sizeof(*closest));
*closest = (dns_slabheader_proof_t){
.neg = r1.base,
.negsig = r2.base,
.name = DNS_NAME_INITEMPTY,
.type = neg.type,
};
dns_name_dup(&name, mctx, &closest->name);
newheader->closest = closest;
cleanup:
dns_rdataset_disassociate(&neg);
dns_rdataset_disassociate(&negsig);
return result;
}
static void
expire_ttl_headers(qpcache_t *qpdb, unsigned int locknum,
isc_rwlocktype_t *nlocktypep, isc_rwlocktype_t *tlocktypep,
isc_stdtime_t now, bool cache_is_overmem DNS__DB_FLARG);
static isc_result_t
addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
isc_stdtime_t now, dns_rdataset_t *rdataset, unsigned int options,
dns_rdataset_t *addedrdataset DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
isc_region_t region;
dns_slabheader_t *newheader = NULL;
isc_result_t result;
bool delegating = false;
bool newnsec;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = NULL;
bool cache_is_overmem = false;
dns_fixedname_t fixed;
dns_name_t *name = NULL;
REQUIRE(VALID_QPDB(qpdb));
REQUIRE(version == NULL);
if (now == 0) {
now = isc_stdtime_now();
}
result = dns_rdataslab_fromrdataset(rdataset, qpdb->common.mctx,
&region, sizeof(dns_slabheader_t),
qpdb->maxrrperset);
if (result != ISC_R_SUCCESS) {
if (result == DNS_R_TOOMANYRECORDS) {
dns__db_logtoomanyrecords((dns_db_t *)qpdb,
&qpnode->name, rdataset->type,
"adding", qpdb->maxrrperset);
}
return result;
}
name = dns_fixedname_initname(&fixed);
dns_name_copy(&qpnode->name, name);
dns_rdataset_getownercase(rdataset, name);
newheader = (dns_slabheader_t *)region.base;
*newheader = (dns_slabheader_t){
.type = DNS_TYPEPAIR_VALUE(rdataset->type, rdataset->covers),
.trust = rdataset->trust,
.last_used = now,
.node = qpnode,
};
dns_slabheader_reset(newheader, db, node);
setttl(newheader, rdataset->ttl + now);
if (rdataset->ttl == 0U) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_ZEROTTL);
}
atomic_init(&newheader->count,
atomic_fetch_add_relaxed(&init_count, 1));
if ((rdataset->attributes & DNS_RDATASETATTR_PREFETCH) != 0) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_PREFETCH);
}
if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_NEGATIVE);
}
if ((rdataset->attributes & DNS_RDATASETATTR_NXDOMAIN) != 0) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_NXDOMAIN);
}
if ((rdataset->attributes & DNS_RDATASETATTR_OPTOUT) != 0) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_OPTOUT);
}
if ((rdataset->attributes & DNS_RDATASETATTR_NOQNAME) != 0) {
result = addnoqname(qpdb->common.mctx, newheader,
qpdb->maxrrperset, rdataset);
if (result != ISC_R_SUCCESS) {
dns_slabheader_destroy(&newheader);
return result;
}
}
if ((rdataset->attributes & DNS_RDATASETATTR_CLOSEST) != 0) {
result = addclosest(qpdb->common.mctx, newheader,
qpdb->maxrrperset, rdataset);
if (result != ISC_R_SUCCESS) {
dns_slabheader_destroy(&newheader);
return result;
}
}
/*
* If we're adding a delegation type (which would be an NS or DNAME
* for a zone, but only DNAME counts for a cache), we need to set
* the callback bit on the node.
*/
if (rdataset->type == dns_rdatatype_dname) {
delegating = true;
}
/*
* Add to the auxiliary NSEC tree if we're adding an NSEC record.
*/
TREE_RDLOCK(&qpdb->tree_lock, &tlocktype);
if (qpnode->nsec != DNS_DB_NSEC_HAS_NSEC &&
rdataset->type == dns_rdatatype_nsec)
{
newnsec = true;
} else {
newnsec = false;
}
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
/*
* If we're adding a delegation type, adding to the auxiliary NSEC
* tree, or the DB is a cache in an overmem state, hold an
* exclusive lock on the tree. In the latter case the lock does
* not necessarily have to be acquired but it will help purge
* ancient entries more effectively.
*/
if (isc_mem_isovermem(qpdb->common.mctx)) {
cache_is_overmem = true;
}
if (delegating || newnsec || cache_is_overmem) {
TREE_WRLOCK(&qpdb->tree_lock, &tlocktype);
}
if (cache_is_overmem) {
overmem(qpdb, newheader, &tlocktype DNS__DB_FLARG_PASS);
}
nlock = &qpdb->buckets[qpnode->locknum].lock;
NODE_WRLOCK(nlock, &nlocktype);
if (qpdb->rrsetstats != NULL) {
DNS_SLABHEADER_SETATTR(newheader, DNS_SLABHEADERATTR_STATCOUNT);
update_rrsetstats(qpdb->rrsetstats, newheader->type,
atomic_load_acquire(&newheader->attributes),
true);
}
expire_ttl_headers(qpdb, qpnode->locknum, &nlocktype, &tlocktype, now,
cache_is_overmem DNS__DB_FLARG_PASS);
/*
* If we've been holding a write lock on the tree just for
* cleaning, we can release it now. However, we still need the
* node lock.
*/
if (tlocktype == isc_rwlocktype_write && !delegating && !newnsec) {
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
}
result = ISC_R_SUCCESS;
if (newnsec) {
qpcnode_t *nsecnode = NULL;
result = dns_qp_getname(qpdb->nsec, name, (void **)&nsecnode,
NULL);
if (result == ISC_R_SUCCESS) {
result = ISC_R_SUCCESS;
} else {
INSIST(nsecnode == NULL);
nsecnode = new_qpcnode(qpdb, name);
nsecnode->nsec = DNS_DB_NSEC_NSEC;
result = dns_qp_insert(qpdb->nsec, nsecnode, 0);
INSIST(result == ISC_R_SUCCESS);
qpcnode_detach(&nsecnode);
}
qpnode->nsec = DNS_DB_NSEC_HAS_NSEC;
}
if (result == ISC_R_SUCCESS) {
result = add(qpdb, qpnode, name, newheader, options, false,
addedrdataset, now, nlocktype,
tlocktype DNS__DB_FLARG_PASS);
}
if (result == ISC_R_SUCCESS && delegating) {
qpnode->delegating = 1;
}
NODE_UNLOCK(nlock, &nlocktype);
if (tlocktype != isc_rwlocktype_none) {
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
}
INSIST(tlocktype == isc_rwlocktype_none);
return result;
}
static isc_result_t
deleterdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
dns_rdatatype_t type, dns_rdatatype_t covers DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
isc_result_t result;
dns_slabheader_t *newheader = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = NULL;
REQUIRE(VALID_QPDB(qpdb));
REQUIRE(version == NULL);
if (type == dns_rdatatype_any) {
return ISC_R_NOTIMPLEMENTED;
}
if (type == dns_rdatatype_rrsig && covers == 0) {
return ISC_R_NOTIMPLEMENTED;
}
newheader = dns_slabheader_new(db, node);
newheader->type = DNS_TYPEPAIR_VALUE(type, covers);
setttl(newheader, 0);
atomic_init(&newheader->attributes, DNS_SLABHEADERATTR_NONEXISTENT);
nlock = &qpdb->buckets[qpnode->locknum].lock;
NODE_WRLOCK(nlock, &nlocktype);
result = add(qpdb, qpnode, NULL, newheader, DNS_DBADD_FORCE, false,
NULL, 0, nlocktype,
isc_rwlocktype_none DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
return result;
}
static unsigned int
nodecount(dns_db_t *db, dns_dbtree_t tree) {
qpcache_t *qpdb = (qpcache_t *)db;
dns_qp_memusage_t mu;
isc_rwlocktype_t tlocktype = isc_rwlocktype_none;
REQUIRE(VALID_QPDB(qpdb));
TREE_RDLOCK(&qpdb->tree_lock, &tlocktype);
switch (tree) {
case dns_dbtree_main:
mu = dns_qp_memusage(qpdb->tree);
break;
case dns_dbtree_nsec:
mu = dns_qp_memusage(qpdb->nsec);
break;
default:
UNREACHABLE();
}
TREE_UNLOCK(&qpdb->tree_lock, &tlocktype);
return mu.leaves;
}
static void
locknode(dns_db_t *db, dns_dbnode_t *node, isc_rwlocktype_t type) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
RWLOCK(&qpdb->buckets[qpnode->locknum].lock, type);
}
static void
unlocknode(dns_db_t *db, dns_dbnode_t *node, isc_rwlocktype_t type) {
qpcache_t *qpdb = (qpcache_t *)db;
qpcnode_t *qpnode = (qpcnode_t *)node;
RWUNLOCK(&qpdb->buckets[qpnode->locknum].lock, type);
}
isc_result_t
dns__qpcache_create(isc_mem_t *mctx, const dns_name_t *origin,
dns_dbtype_t type, dns_rdataclass_t rdclass,
unsigned int argc, char *argv[],
void *driverarg ISC_ATTR_UNUSED, dns_db_t **dbp) {
qpcache_t *qpdb = NULL;
isc_mem_t *hmctx = mctx;
isc_loop_t *loop = isc_loop();
int i;
isc_loopmgr_t *loopmgr = isc_loop_getloopmgr(loop);
size_t nloops = isc_loopmgr_nloops(loopmgr);
/* This database implementation only supports cache semantics */
REQUIRE(type == dns_dbtype_cache);
REQUIRE(loop != NULL);
qpdb = isc_mem_get(mctx,
sizeof(*qpdb) + nloops * sizeof(qpdb->buckets[0]));
*qpdb = (qpcache_t){
.common.methods = &qpdb_cachemethods,
.common.origin = DNS_NAME_INITEMPTY,
.common.rdclass = rdclass,
.common.attributes = DNS_DBATTR_CACHE,
.common.references = 1,
.loopmgr = isc_loop_getloopmgr(loop),
.references = 1,
.buckets_count = nloops,
};
/*
* If argv[0] exists, it points to a memory context to use for heap
*/
if (argc != 0) {
hmctx = (isc_mem_t *)argv[0];
}
isc_rwlock_init(&qpdb->lock);
TREE_INITLOCK(&qpdb->tree_lock);
qpdb->buckets_count = isc_loopmgr_nloops(qpdb->loopmgr);
dns_rdatasetstats_create(mctx, &qpdb->rrsetstats);
for (i = 0; i < (int)qpdb->buckets_count; i++) {
ISC_LIST_INIT(qpdb->buckets[i].lru);
qpdb->buckets[i].heap = NULL;
isc_heap_create(hmctx, ttl_sooner, set_index, 0,
&qpdb->buckets[i].heap);
isc_queue_init(&qpdb->buckets[i].deadnodes);
NODE_INITLOCK(&qpdb->buckets[i].lock);
}
/*
* Attach to the mctx. The database will persist so long as there
* are references to it, and attaching to the mctx ensures that our
* mctx won't disappear out from under us.
*/
isc_mem_attach(mctx, &qpdb->common.mctx);
isc_mem_attach(hmctx, &qpdb->hmctx);
/*
* Make a copy of the origin name.
*/
dns_name_dupwithoffsets(origin, mctx, &qpdb->common.origin);
/*
* Make the qp tries.
*/
dns_qp_create(mctx, &qpmethods, qpdb, &qpdb->tree);
dns_qp_create(mctx, &qpmethods, qpdb, &qpdb->nsec);
qpdb->common.magic = DNS_DB_MAGIC;
qpdb->common.impmagic = QPDB_MAGIC;
*dbp = (dns_db_t *)qpdb;
return ISC_R_SUCCESS;
}
/*
* Rdataset Iterator Methods
*/
static void
rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp DNS__DB_FLARG) {
qpc_rditer_t *iterator = NULL;
iterator = (qpc_rditer_t *)(*iteratorp);
dns__db_detachnode(iterator->common.db,
&iterator->common.node DNS__DB_FLARG_PASS);
isc_mem_put(iterator->common.db->mctx, iterator, sizeof(*iterator));
*iteratorp = NULL;
}
static bool
iterator_active(qpcache_t *qpdb, qpc_rditer_t *iterator,
dns_slabheader_t *header) {
dns_ttl_t stale_ttl = header->ttl + STALE_TTL(header, qpdb);
/*
* Is this a "this rdataset doesn't exist" record?
*/
if (NONEXISTENT(header)) {
return false;
}
/*
* If this header is still active then return it.
*/
if (ACTIVE(header, iterator->common.now)) {
return true;
}
/*
* If we are not returning stale records or the rdataset is
* too old don't return it.
*/
if (!STALEOK(iterator) || (iterator->common.now > stale_ttl)) {
return false;
}
return true;
}
static isc_result_t
rdatasetiter_first(dns_rdatasetiter_t *it DNS__DB_FLARG) {
qpc_rditer_t *iterator = (qpc_rditer_t *)it;
qpcache_t *qpdb = (qpcache_t *)(iterator->common.db);
qpcnode_t *qpnode = iterator->common.node;
dns_slabheader_t *header = NULL, *top_next = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[qpnode->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
for (header = qpnode->data; header != NULL; header = top_next) {
top_next = header->next;
do {
if (EXPIREDOK(iterator)) {
if (!NONEXISTENT(header)) {
break;
}
header = header->down;
} else if (!IGNORE(header)) {
if (!iterator_active(qpdb, iterator, header)) {
header = NULL;
}
break;
} else {
header = header->down;
}
} while (header != NULL);
if (header != NULL) {
break;
}
}
NODE_UNLOCK(nlock, &nlocktype);
iterator->current = header;
if (header == NULL) {
return ISC_R_NOMORE;
}
return ISC_R_SUCCESS;
}
static isc_result_t
rdatasetiter_next(dns_rdatasetiter_t *it DNS__DB_FLARG) {
qpc_rditer_t *iterator = (qpc_rditer_t *)it;
qpcache_t *qpdb = (qpcache_t *)(iterator->common.db);
qpcnode_t *qpnode = iterator->common.node;
dns_slabheader_t *header = NULL, *top_next = NULL;
dns_typepair_t type, negtype;
dns_rdatatype_t rdtype, covers;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[qpnode->locknum].lock;
bool expiredok = EXPIREDOK(iterator);
header = iterator->current;
if (header == NULL) {
return ISC_R_NOMORE;
}
NODE_RDLOCK(nlock, &nlocktype);
type = header->type;
rdtype = DNS_TYPEPAIR_TYPE(header->type);
if (NEGATIVE(header)) {
covers = DNS_TYPEPAIR_COVERS(header->type);
negtype = DNS_TYPEPAIR_VALUE(covers, 0);
} else {
negtype = DNS_TYPEPAIR_VALUE(0, rdtype);
}
/*
* Find the start of the header chain for the next type
* by walking back up the list.
*/
top_next = header->next;
while (top_next != NULL &&
(top_next->type == type || top_next->type == negtype))
{
top_next = top_next->next;
}
if (expiredok) {
/*
* Keep walking down the list if possible or
* start the next type.
*/
header = header->down != NULL ? header->down : top_next;
} else {
header = top_next;
}
for (; header != NULL; header = top_next) {
top_next = header->next;
do {
if (expiredok) {
if (!NONEXISTENT(header)) {
break;
}
header = header->down;
} else if (!IGNORE(header)) {
if (!iterator_active(qpdb, iterator, header)) {
header = NULL;
}
break;
} else {
header = header->down;
}
} while (header != NULL);
if (header != NULL) {
break;
}
/*
* Find the start of the header chain for the next type
* by walking back up the list.
*/
while (top_next != NULL &&
(top_next->type == type || top_next->type == negtype))
{
top_next = top_next->next;
}
}
NODE_UNLOCK(nlock, &nlocktype);
iterator->current = header;
if (header == NULL) {
return ISC_R_NOMORE;
}
return ISC_R_SUCCESS;
}
static void
rdatasetiter_current(dns_rdatasetiter_t *it,
dns_rdataset_t *rdataset DNS__DB_FLARG) {
qpc_rditer_t *iterator = (qpc_rditer_t *)it;
qpcache_t *qpdb = (qpcache_t *)(iterator->common.db);
qpcnode_t *qpnode = iterator->common.node;
dns_slabheader_t *header = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlock_t *nlock = &qpdb->buckets[qpnode->locknum].lock;
header = iterator->current;
REQUIRE(header != NULL);
NODE_RDLOCK(nlock, &nlocktype);
bindrdataset(qpdb, qpnode, header, iterator->common.now, nlocktype,
isc_rwlocktype_none, rdataset DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
}
/*
* Database Iterator Methods
*/
static void
reference_iter_node(qpc_dbit_t *qpdbiter DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)qpdbiter->common.db;
qpcnode_t *node = qpdbiter->node;
if (node == NULL) {
return;
}
INSIST(qpdbiter->tree_locked != isc_rwlocktype_none);
reactivate_node(qpdb, node, qpdbiter->tree_locked DNS__DB_FLARG_PASS);
}
static void
dereference_iter_node(qpc_dbit_t *qpdbiter DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)qpdbiter->common.db;
qpcnode_t *node = qpdbiter->node;
isc_rwlock_t *nlock = NULL;
isc_rwlocktype_t nlocktype = isc_rwlocktype_none;
isc_rwlocktype_t tlocktype = qpdbiter->tree_locked;
if (node == NULL) {
return;
}
REQUIRE(tlocktype != isc_rwlocktype_write);
nlock = &qpdb->buckets[node->locknum].lock;
NODE_RDLOCK(nlock, &nlocktype);
qpcnode_release(qpdb, node, &nlocktype, &qpdbiter->tree_locked,
false DNS__DB_FLARG_PASS);
NODE_UNLOCK(nlock, &nlocktype);
INSIST(qpdbiter->tree_locked == tlocktype);
qpdbiter->node = NULL;
}
static void
resume_iteration(qpc_dbit_t *qpdbiter, bool continuing) {
qpcache_t *qpdb = (qpcache_t *)qpdbiter->common.db;
REQUIRE(qpdbiter->paused);
REQUIRE(qpdbiter->tree_locked == isc_rwlocktype_none);
TREE_RDLOCK(&qpdb->tree_lock, &qpdbiter->tree_locked);
/*
* If we're being called from dbiterator_next or _prev,
* then we may need to reinitialize the iterator to the current
* name. The tree could have changed while it was unlocked,
* would make the iterator traversal inconsistent.
*
* As long as the iterator is holding a reference to
* qpdbiter->node, the node won't be removed from the tree,
* so the lookup should always succeed.
*/
if (continuing && qpdbiter->node != NULL) {
isc_result_t result;
result = dns_qp_lookup(qpdb->tree, qpdbiter->name, NULL,
&qpdbiter->iter, NULL, NULL, NULL);
INSIST(result == ISC_R_SUCCESS);
}
qpdbiter->paused = false;
}
static void
dbiterator_destroy(dns_dbiterator_t **iteratorp DNS__DB_FLARG) {
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)(*iteratorp);
qpcache_t *qpdb = (qpcache_t *)qpdbiter->common.db;
dns_db_t *db = NULL;
if (qpdbiter->tree_locked == isc_rwlocktype_read) {
TREE_UNLOCK(&qpdb->tree_lock, &qpdbiter->tree_locked);
}
INSIST(qpdbiter->tree_locked == isc_rwlocktype_none);
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
dns_db_attach(qpdbiter->common.db, &db);
dns_db_detach(&qpdbiter->common.db);
isc_mem_put(db->mctx, qpdbiter, sizeof(*qpdbiter));
dns_db_detach(&db);
*iteratorp = NULL;
}
static isc_result_t
dbiterator_first(dns_dbiterator_t *iterator DNS__DB_FLARG) {
isc_result_t result;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
qpcache_t *qpdb = (qpcache_t *)iterator->db;
if (qpdbiter->result != ISC_R_SUCCESS &&
qpdbiter->result != ISC_R_NOTFOUND &&
qpdbiter->result != DNS_R_PARTIALMATCH &&
qpdbiter->result != ISC_R_NOMORE)
{
return qpdbiter->result;
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
dns_qpiter_init(qpdb->tree, &qpdbiter->iter);
result = dns_qpiter_next(&qpdbiter->iter, NULL,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS) {
dns_name_copy(&qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE); /* The tree is empty. */
qpdbiter->node = NULL;
}
qpdbiter->result = result;
if (result != ISC_R_SUCCESS) {
ENSURE(!qpdbiter->paused);
}
return result;
}
static isc_result_t
dbiterator_last(dns_dbiterator_t *iterator DNS__DB_FLARG) {
isc_result_t result;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
qpcache_t *qpdb = (qpcache_t *)iterator->db;
if (qpdbiter->result != ISC_R_SUCCESS &&
qpdbiter->result != ISC_R_NOTFOUND &&
qpdbiter->result != DNS_R_PARTIALMATCH &&
qpdbiter->result != ISC_R_NOMORE)
{
return qpdbiter->result;
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
dns_qpiter_init(qpdb->tree, &qpdbiter->iter);
result = dns_qpiter_prev(&qpdbiter->iter, NULL,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS) {
dns_name_copy(&qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE); /* The tree is empty. */
qpdbiter->node = NULL;
}
qpdbiter->result = result;
return result;
}
static isc_result_t
dbiterator_seek(dns_dbiterator_t *iterator,
const dns_name_t *name DNS__DB_FLARG) {
isc_result_t result;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
qpcache_t *qpdb = (qpcache_t *)iterator->db;
if (qpdbiter->result != ISC_R_SUCCESS &&
qpdbiter->result != ISC_R_NOTFOUND &&
qpdbiter->result != DNS_R_PARTIALMATCH &&
qpdbiter->result != ISC_R_NOMORE)
{
return qpdbiter->result;
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter, false);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
result = dns_qp_lookup(qpdb->tree, name, NULL, &qpdbiter->iter, NULL,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
dns_name_copy(&qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
qpdbiter->node = NULL;
}
qpdbiter->result = (result == DNS_R_PARTIALMATCH) ? ISC_R_SUCCESS
: result;
return result;
}
static isc_result_t
dbiterator_prev(dns_dbiterator_t *iterator DNS__DB_FLARG) {
isc_result_t result;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
REQUIRE(qpdbiter->node != NULL);
if (qpdbiter->result != ISC_R_SUCCESS) {
return qpdbiter->result;
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter, true);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
result = dns_qpiter_prev(&qpdbiter->iter, NULL,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS) {
dns_name_copy(&qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE);
qpdbiter->node = NULL;
}
qpdbiter->result = result;
return result;
}
static isc_result_t
dbiterator_next(dns_dbiterator_t *iterator DNS__DB_FLARG) {
isc_result_t result;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
REQUIRE(qpdbiter->node != NULL);
if (qpdbiter->result != ISC_R_SUCCESS) {
return qpdbiter->result;
}
if (qpdbiter->paused) {
resume_iteration(qpdbiter, true);
}
dereference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
result = dns_qpiter_next(&qpdbiter->iter, NULL,
(void **)&qpdbiter->node, NULL);
if (result == ISC_R_SUCCESS) {
dns_name_copy(&qpdbiter->node->name, qpdbiter->name);
reference_iter_node(qpdbiter DNS__DB_FLARG_PASS);
} else {
INSIST(result == ISC_R_NOMORE);
qpdbiter->node = NULL;
}
qpdbiter->result = result;
return result;
}
static isc_result_t
dbiterator_current(dns_dbiterator_t *iterator, dns_dbnode_t **nodep,
dns_name_t *name DNS__DB_FLARG) {
qpcache_t *qpdb = (qpcache_t *)iterator->db;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
qpcnode_t *node = qpdbiter->node;
REQUIRE(qpdbiter->result == ISC_R_SUCCESS);
REQUIRE(node != NULL);
if (qpdbiter->paused) {
resume_iteration(qpdbiter, false);
}
if (name != NULL) {
dns_name_copy(&node->name, name);
}
qpcnode_acquire(qpdb, node, isc_rwlocktype_none,
qpdbiter->tree_locked DNS__DB_FLARG_PASS);
*nodep = qpdbiter->node;
return ISC_R_SUCCESS;
}
static isc_result_t
dbiterator_pause(dns_dbiterator_t *iterator) {
qpcache_t *qpdb = (qpcache_t *)iterator->db;
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
if (qpdbiter->result != ISC_R_SUCCESS &&
qpdbiter->result != ISC_R_NOTFOUND &&
qpdbiter->result != DNS_R_PARTIALMATCH &&
qpdbiter->result != ISC_R_NOMORE)
{
return qpdbiter->result;
}
if (qpdbiter->paused) {
return ISC_R_SUCCESS;
}
qpdbiter->paused = true;
if (qpdbiter->tree_locked == isc_rwlocktype_read) {
TREE_UNLOCK(&qpdb->tree_lock, &qpdbiter->tree_locked);
}
INSIST(qpdbiter->tree_locked == isc_rwlocktype_none);
return ISC_R_SUCCESS;
}
static isc_result_t
dbiterator_origin(dns_dbiterator_t *iterator, dns_name_t *name) {
qpc_dbit_t *qpdbiter = (qpc_dbit_t *)iterator;
if (qpdbiter->result != ISC_R_SUCCESS) {
return qpdbiter->result;
}
dns_name_copy(dns_rootname, name);
return ISC_R_SUCCESS;
}
static void
deletedata(dns_db_t *db ISC_ATTR_UNUSED, dns_dbnode_t *node ISC_ATTR_UNUSED,
void *data) {
dns_slabheader_t *header = data;
qpcache_t *qpdb = (qpcache_t *)header->db;
if (header->heap != NULL && header->heap_index != 0) {
isc_heap_delete(header->heap, header->heap_index);
}
update_rrsetstats(qpdb->rrsetstats, header->type,
atomic_load_acquire(&header->attributes), false);
if (ISC_LINK_LINKED(header, link)) {
int idx = HEADERNODE(header)->locknum;
ISC_LIST_UNLINK(qpdb->buckets[idx].lru, header, link);
}
if (header->noqname != NULL) {
dns_slabheader_freeproof(db->mctx, &header->noqname);
}
if (header->closest != NULL) {
dns_slabheader_freeproof(db->mctx, &header->closest);
}
}
/*
* Caller must be holding the node write lock.
*/
static void
expire_ttl_headers(qpcache_t *qpdb, unsigned int locknum,
isc_rwlocktype_t *nlocktypep, isc_rwlocktype_t *tlocktypep,
isc_stdtime_t now, bool cache_is_overmem DNS__DB_FLARG) {
isc_heap_t *heap = qpdb->buckets[locknum].heap;
for (size_t i = 0; i < DNS_QPDB_EXPIRE_TTL_COUNT; i++) {
dns_slabheader_t *header = isc_heap_element(heap, 1);
if (header == NULL) {
/* No headers left on this TTL heap; exit cleaning */
return;
}
dns_ttl_t ttl = header->ttl;
if (!cache_is_overmem) {
/* Only account for stale TTL if cache is not overmem */
ttl += STALE_TTL(header, qpdb);
}
if (ttl >= now - QPDB_VIRTUAL) {
/*
* The header at the top of this TTL heap is not yet
* eligible for expiry, so none of the other headers on
* the same heap can be eligible for expiry, either;
* exit cleaning.
*/
return;
}
expireheader(header, nlocktypep, tlocktypep,
dns_expire_ttl DNS__DB_FLARG_PASS);
}
}
static void
setmaxrrperset(dns_db_t *db, uint32_t value) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
qpdb->maxrrperset = value;
}
static void
setmaxtypepername(dns_db_t *db, uint32_t value) {
qpcache_t *qpdb = (qpcache_t *)db;
REQUIRE(VALID_QPDB(qpdb));
qpdb->maxtypepername = value;
}
static dns_dbmethods_t qpdb_cachemethods = {
.destroy = qpdb_destroy,
.findnode = findnode,
.find = find,
.findzonecut = findzonecut,
.attachnode = attachnode,
.detachnode = detachnode,
.createiterator = createiterator,
.findrdataset = findrdataset,
.allrdatasets = allrdatasets,
.addrdataset = addrdataset,
.deleterdataset = deleterdataset,
.nodecount = nodecount,
.getrrsetstats = getrrsetstats,
.setcachestats = setcachestats,
.setservestalettl = setservestalettl,
.getservestalettl = getservestalettl,
.setservestalerefresh = setservestalerefresh,
.getservestalerefresh = getservestalerefresh,
.locknode = locknode,
.unlocknode = unlocknode,
.expiredata = expiredata,
.deletedata = deletedata,
.setmaxrrperset = setmaxrrperset,
.setmaxtypepername = setmaxtypepername,
};
static void
qpcnode_destroy(qpcnode_t *data) {
dns_slabheader_t *current = NULL, *next = NULL;
for (current = data->data; current != NULL; current = next) {
dns_slabheader_t *down = current->down, *down_next = NULL;
next = current->next;
for (down = current->down; down != NULL; down = down_next) {
down_next = down->down;
dns_slabheader_destroy(&down);
}
dns_slabheader_destroy(&current);
}
dns_name_free(&data->name, data->mctx);
isc_mem_putanddetach(&data->mctx, data, sizeof(qpcnode_t));
}
#ifdef DNS_DB_NODETRACE
ISC_REFCOUNT_STATIC_TRACE_IMPL(qpcnode, qpcnode_destroy);
#else
ISC_REFCOUNT_STATIC_IMPL(qpcnode, qpcnode_destroy);
#endif
#ifdef DNS_DB_NODETRACE
ISC_REFCOUNT_STATIC_TRACE_IMPL(qpcache, qpcache__destroy);
#else
ISC_REFCOUNT_STATIC_IMPL(qpcache, qpcache__destroy);
#endif