3 * Copyright 1998-2000 The OpenLDAP Foundation, All Rights Reserved.
4 * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
7 * Copyright (c) 1993 The Regents of the University of Michigan.
10 * cache.c - local caching support for LDAP
17 #include <ac/stdlib.h>
19 #include <ac/socket.h>
20 #include <ac/string.h>
27 static int cache_hash LDAP_P(( BerElement *ber ));
28 static LDAPMessage *msg_dup LDAP_P(( LDAPMessage *msg ));
29 static int request_cmp LDAP_P(( BerElement *req1, BerElement *req2 ));
30 static int chain_contains_dn LDAP_P(( LDAPMessage *msg, LDAP_CONST char *dn ));
31 static ber_len_t msg_size LDAP_P(( LDAPMessage *msg ));
32 static void check_cache_memused LDAP_P(( LDAPCache *lc ));
33 static void uncache_entry_or_req LDAP_P(( LDAP *ld, LDAP_CONST char *dn, ber_int_t msgid ));
38 ldap_enable_cache( LDAP *ld, long timeout, ber_len_t maxmem )
41 if ( ld->ld_cache == NULL ) {
42 if (( ld->ld_cache = (LDAPCache *)LDAP_MALLOC( sizeof( LDAPCache )))
44 ld->ld_errno = LDAP_NO_MEMORY;
47 (void) memset( ld->ld_cache, 0, sizeof( LDAPCache ));
48 ld->ld_cache->lc_memused = sizeof( LDAPCache );
51 ld->ld_cache->lc_timeout = timeout;
52 ld->ld_cache->lc_maxmem = maxmem;
53 check_cache_memused( ld->ld_cache );
54 ld->ld_cache->lc_enabled = 1;
63 ldap_disable_cache( LDAP *ld )
66 if ( ld->ld_cache != NULL ) {
67 ld->ld_cache->lc_enabled = 0;
75 ldap_set_cache_options( LDAP *ld, unsigned long opts )
78 if ( ld->ld_cache != NULL ) {
79 ld->ld_cache->lc_options = opts;
86 ldap_destroy_cache( LDAP *ld )
89 if ( ld->ld_cache != NULL ) {
90 ldap_flush_cache( ld );
91 LDAP_FREE( (char *)ld->ld_cache );
99 ldap_flush_cache( LDAP *ld )
103 LDAPMessage *m, *next;
105 Debug( LDAP_DEBUG_TRACE, "ldap_flush_cache\n", 0, 0, 0 );
107 if ( ld->ld_cache != NULL ) {
108 /* delete all requests in the queue */
109 for ( m = ld->ld_cache->lc_requests; m != NULL; m = next ) {
113 ld->ld_cache->lc_requests = NULL;
115 /* delete all messages in the cache */
116 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
117 for ( m = ld->ld_cache->lc_buckets[ i ];
118 m != NULL; m = next ) {
122 ld->ld_cache->lc_buckets[ i ] = NULL;
124 ld->ld_cache->lc_memused = sizeof( LDAPCache );
131 ldap_uncache_request( LDAP *ld, int msgid )
134 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_request %d ld_cache %lx\n",
135 msgid, (long) ld->ld_cache, 0 );
137 uncache_entry_or_req( ld, NULL, msgid );
143 ldap_uncache_entry( LDAP *ld, LDAP_CONST char *dn )
146 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_entry %s ld_cache %lx\n",
147 dn, (long) ld->ld_cache, 0 );
149 uncache_entry_or_req( ld, dn, 0 );
157 uncache_entry_or_req( LDAP *ld,
158 const char *dn, /* if non-NULL, uncache entry */
159 ber_int_t msgid ) /* request to uncache (if dn == NULL) */
162 LDAPMessage *m, *prev, *next;
164 Debug( LDAP_DEBUG_TRACE,
165 "ldap_uncache_entry_or_req dn %s msgid %ld ld_cache %lx\n",
166 dn, (long) msgid, (long) ld->ld_cache );
168 if ( ld->ld_cache == NULL ) {
172 /* first check the request queue */
174 for ( m = ld->ld_cache->lc_requests; m != NULL; m = next ) {
176 if (( dn != NULL && chain_contains_dn( m, dn )) ||
177 ( dn == NULL && m->lm_msgid == msgid )) {
178 if ( prev == NULL ) {
179 ld->ld_cache->lc_requests = next;
181 prev->lm_next = next;
183 ld->ld_cache->lc_memused -= msg_size( m );
190 /* now check the rest of the cache */
191 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
193 for ( m = ld->ld_cache->lc_buckets[ i ]; m != NULL;
196 if (( dn != NULL && chain_contains_dn( m, dn )) ||
197 ( dn == NULL && m->lm_msgid == msgid )) {
198 if ( prev == NULL ) {
199 ld->ld_cache->lc_buckets[ i ] = next;
201 prev->lm_next = next;
203 ld->ld_cache->lc_memused -= msg_size( m );
215 ldap_add_request_to_cache( LDAP *ld, ber_tag_t msgtype, BerElement *request )
221 Debug( LDAP_DEBUG_TRACE, "ldap_add_request_to_cache\n", 0, 0, 0 );
223 ld->ld_errno = LDAP_SUCCESS;
224 if ( ld->ld_cache == NULL ||
225 ( ld->ld_cache->lc_enabled == 0 )) {
229 if (( new = (LDAPMessage *) LDAP_CALLOC( 1, sizeof(LDAPMessage) ))
231 if (( new->lm_ber = ldap_alloc_ber_with_options( ld )) == NULL ) {
232 LDAP_FREE( (char *)new );
235 len = request->ber_ptr - request->ber_buf;
236 if (( new->lm_ber->ber_buf = (char *) ber_memalloc( (size_t)len ))
238 ber_free( new->lm_ber, 0 );
239 LDAP_FREE( (char *)new );
240 ld->ld_errno = LDAP_NO_MEMORY;
243 SAFEMEMCPY( new->lm_ber->ber_buf, request->ber_buf,
245 new->lm_ber->ber_ptr = new->lm_ber->ber_buf;
246 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
247 new->lm_msgid = ld->ld_msgid;
248 new->lm_msgtype = msgtype;;
249 new->lm_next = ld->ld_cache->lc_requests;
250 ld->ld_cache->lc_requests = new;
252 ld->ld_errno = LDAP_NO_MEMORY;
259 ldap_add_result_to_cache( LDAP *ld, LDAPMessage *result )
262 LDAPMessage *m, **mp, *req, *new, *prev;
265 Debug( LDAP_DEBUG_TRACE, "ldap_add_result_to_cache: id %ld, type %ld\n",
266 (long) result->lm_msgid, (long) result->lm_msgtype, 0 );
268 if ( ld->ld_cache == NULL ||
269 ( ld->ld_cache->lc_enabled == 0 )) {
270 Debug( LDAP_DEBUG_TRACE, "artc: cache disabled\n", 0, 0, 0 );
274 if ( result->lm_msgtype != LDAP_RES_SEARCH_ENTRY &&
275 result->lm_msgtype != LDAP_RES_SEARCH_REFERENCE &&
276 result->lm_msgtype != LDAP_RES_SEARCH_RESULT &&
277 result->lm_msgtype != LDAP_RES_COMPARE ) {
279 * only cache search and compare operations
281 Debug( LDAP_DEBUG_TRACE,
282 "artc: only caching search & compare operations\n", 0, 0, 0 );
287 * if corresponding request is in the lc_requests list, add this
288 * result to it. if this result completes the results for the
289 * request, add the request/result chain to the cache proper.
292 for ( m = ld->ld_cache->lc_requests; m != NULL; m = m->lm_next ) {
293 if ( m->lm_msgid == result->lm_msgid ) {
299 if ( m != NULL ) { /* found request; add to end of chain */
301 for ( ; m->lm_chain != NULL; m = m->lm_chain )
303 if (( new = msg_dup( result )) != NULL ) {
304 new->lm_chain = NULL;
306 Debug( LDAP_DEBUG_TRACE,
307 "artc: result added to cache request chain\n",
310 if ( result->lm_msgtype == LDAP_RES_SEARCH_RESULT ||
311 result->lm_msgtype == LDAP_RES_COMPARE ) {
313 * this result completes the chain of results
314 * add to cache proper if appropriate
316 keep = 0; /* pessimistic */
317 err = ldap_result2error( ld, result, 0 );
318 if ( err == LDAP_SUCCESS ||
319 ( result->lm_msgtype == LDAP_RES_COMPARE &&
320 ( err == LDAP_COMPARE_FALSE ||
321 err == LDAP_COMPARE_TRUE ||
322 err == LDAP_NO_SUCH_ATTRIBUTE ))) {
326 if ( ld->ld_cache->lc_options == 0 ) {
327 if ( err == LDAP_SIZELIMIT_EXCEEDED ) {
330 } else if (( ld->ld_cache->lc_options &
331 LDAP_CACHE_OPT_CACHEALLERRS ) != 0 ) {
335 if ( prev == NULL ) {
336 ld->ld_cache->lc_requests = req->lm_next;
338 prev->lm_next = req->lm_next;
342 Debug( LDAP_DEBUG_TRACE,
343 "artc: not caching result with error %d\n",
347 mp = &ld->ld_cache->lc_buckets[
348 cache_hash( req->lm_ber ) ];
351 req->lm_time = (long) time( NULL );
352 ld->ld_cache->lc_memused += msg_size( req );
353 check_cache_memused( ld->ld_cache );
354 Debug( LDAP_DEBUG_TRACE,
355 "artc: cached result with error %d\n",
360 Debug( LDAP_DEBUG_TRACE, "artc: msgid not in request list\n",
368 * look in the cache for this request
369 * return 0 if found, -1 if not
370 * if found, the corresponding result messages are added to the incoming
371 * queue with the correct (new) msgid so that subsequent ldap_result calls
375 ldap_check_cache( LDAP *ld, ber_tag_t msgtype, BerElement *request )
378 LDAPMessage *m, *new, *prev, *next;
383 Debug( LDAP_DEBUG_TRACE, "ldap_check_cache\n", 0, 0, 0 );
385 if ( ld->ld_cache == NULL ||
386 ( ld->ld_cache->lc_enabled == 0 )) {
390 reqber.ber_valid = LBER_VALID_BERELEMENT;
391 reqber.ber_buf = reqber.ber_ptr = request->ber_buf;
392 reqber.ber_end = request->ber_ptr;
394 c_time = time( NULL );
397 hash = cache_hash( &reqber );
398 for ( m = ld->ld_cache->lc_buckets[ hash ]; m != NULL; m = next ) {
399 Debug( LDAP_DEBUG_TRACE,"cc: examining id %ld,type %ld\n",
400 (long) m->lm_msgid, (long) m->lm_msgtype, 0 );
401 if ( difftime(c_time, m->lm_time) > ld->ld_cache->lc_timeout ) {
402 /* delete expired message */
404 if ( prev == NULL ) {
405 ld->ld_cache->lc_buckets[ hash ] = next;
407 prev->lm_next = next;
409 Debug( LDAP_DEBUG_TRACE, "cc: expired id %d\n",
411 ld->ld_cache->lc_memused -= msg_size( m );
414 if ( m->lm_msgtype == (int)msgtype &&
415 request_cmp( m->lm_ber, &reqber ) == 0 ) {
428 * add duplicates of responses to incoming queue
431 for ( m = m->lm_chain; m != NULL; m = m->lm_chain ) {
432 if (( new = msg_dup( m )) == NULL ) {
436 new->lm_msgid = ld->ld_msgid;
437 new->lm_chain = NULL;
439 new->lm_next = ld->ld_responses;
440 ld->ld_responses = new;
443 prev->lm_chain = new;
446 Debug( LDAP_DEBUG_TRACE, "cc: added type %ld\n",
447 (long) new->lm_msgtype, 0, 0 );
450 Debug( LDAP_DEBUG_TRACE, "cc: result returned from cache\n", 0, 0, 0 );
460 cache_hash( BerElement *ber )
466 * just take the length of the packet and mod with # of buckets
469 if ( ber_skip_tag( &bercpy, &len ) == LBER_ERROR
470 || ber_scanf( &bercpy, "x" ) == LBER_ERROR ) {
471 len = 0; /* punt: just return zero */
473 len = bercpy.ber_end - bercpy.ber_ptr;
476 Debug( LDAP_DEBUG_TRACE, "cache_hash: len is %ld, returning %ld\n",
477 len, len % LDAP_CACHE_BUCKETS, 0 );
478 return( (int) ( len % LDAP_CACHE_BUCKETS ));
483 msg_dup( LDAPMessage *msg )
488 if (( new = (LDAPMessage *)LDAP_MALLOC( sizeof(LDAPMessage))) != NULL ) {
489 *new = *msg; /* struct copy */
490 if (( new->lm_ber = ber_dup( msg->lm_ber )) == NULL ) {
491 LDAP_FREE( (char *)new );
494 len = msg->lm_ber->ber_end - msg->lm_ber->ber_buf;
495 if (( new->lm_ber->ber_buf = (char *) ber_memalloc(
496 (size_t)len )) == NULL ) {
497 ber_free( new->lm_ber, 0 );
498 LDAP_FREE( (char *)new );
501 SAFEMEMCPY( new->lm_ber->ber_buf, msg->lm_ber->ber_buf,
503 new->lm_ber->ber_ptr = new->lm_ber->ber_buf +
504 ( msg->lm_ber->ber_ptr - msg->lm_ber->ber_buf );
505 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
513 request_cmp( BerElement *req1, BerElement *req2 )
518 r1 = *req1; /* struct copies */
522 * skip the enclosing tags (sequence markers) and the msg ids
524 if ( ber_skip_tag( &r1, &len ) == LBER_ERROR || ber_scanf( &r1, "x" )
528 if ( ber_skip_tag( &r2, &len ) == LBER_ERROR || ber_scanf( &r2, "x" )
534 * check remaining length and bytes if necessary
536 if (( len = r1.ber_end - r1.ber_ptr ) !=
537 (ber_len_t) (r2.ber_end - r2.ber_ptr) )
539 return( -1 ); /* different lengths */
541 return( memcmp( r1.ber_ptr, r2.ber_ptr, (size_t)len ));
546 chain_contains_dn( LDAPMessage *msg, const char *dn )
556 * first check the base or dn of the request
558 ber = *msg->lm_ber; /* struct copy */
559 if ( ber_scanf( &ber, "{i{a" /*}}*/, &msgid, &s ) != LBER_ERROR ) {
560 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
567 if ( msg->lm_msgtype == LDAP_REQ_COMPARE ) {
572 * now check the dn of each search result
575 for ( m = msg->lm_chain; m != NULL && rc == 0 ; m = m->lm_chain ) {
576 if ( m->lm_msgtype != LDAP_RES_SEARCH_ENTRY ) {
579 ber = *m->lm_ber; /* struct copy */
580 if ( ber_scanf( &ber, "{a" /*}*/, &s ) != LBER_ERROR ) {
581 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
591 msg_size( LDAPMessage *msg )
597 for ( m = msg; m != NULL; m = m->lm_chain ) {
598 size += ( sizeof( LDAPMessage ) + m->lm_ber->ber_end -
599 m->lm_ber->ber_buf );
606 #define THRESHOLD_FACTOR 3 / 4
607 #define SIZE_FACTOR 2 / 3
610 check_cache_memused( LDAPCache *lc )
613 * this routine is called to check if the cache is too big (lc_maxmem >
614 * minimum cache size and lc_memused > lc_maxmem). If too big, it reduces
615 * the cache size to < SIZE_FACTOR * lc_maxmem. The algorithm is as follows:
616 * remove_threshold = lc_timeout seconds;
618 * remove everything older than remove_threshold seconds;
619 * remove_threshold = remove_threshold * THRESHOLD_FACTOR;
620 * } while ( cache size is > SIZE_FACTOR * lc_maxmem )
623 unsigned long remove_threshold;
625 LDAPMessage *m, *prev, *next;
627 Debug( LDAP_DEBUG_TRACE, "check_cache_memused: %ld bytes in use (%ld max)\n",
628 lc->lc_memused, lc->lc_maxmem, 0 );
630 if ( (unsigned) lc->lc_maxmem <= sizeof( LDAPCache )
631 || lc->lc_memused <= lc->lc_maxmem * SIZE_FACTOR ) {
635 remove_threshold = lc->lc_timeout;
636 while ( lc->lc_memused > lc->lc_maxmem * SIZE_FACTOR ) {
637 c_time = time( NULL );
638 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
640 for ( m = lc->lc_buckets[ i ]; m != NULL;
643 if ( difftime(c_time, m->lm_time) > remove_threshold) {
644 if ( prev == NULL ) {
645 lc->lc_buckets[ i ] = next;
647 prev->lm_next = next;
649 lc->lc_memused -= msg_size( m );
650 Debug( LDAP_DEBUG_TRACE,
659 remove_threshold *= THRESHOLD_FACTOR;
662 Debug( LDAP_DEBUG_TRACE, "ccm: reduced usage to %ld bytes\n",
663 lc->lc_memused, 0, 0 );
666 #endif /* !NO_CACHE */