2 * Copyright (c) 1993 The Regents of the University of Michigan.
5 * cache.c - local caching support for LDAP
12 static char copyright[] = "@(#) Copyright (c) 1993 The Regents of the University of Michigan.\nAll rights reserved.\n";
18 #include <ac/socket.h>
19 #include <ac/string.h>
28 static int cache_hash LDAP_P(( BerElement *ber ));
29 static LDAPMessage *msg_dup LDAP_P(( LDAPMessage *msg ));
30 static int request_cmp LDAP_P(( BerElement *req1, BerElement *req2 ));
31 static int chain_contains_dn LDAP_P(( LDAPMessage *msg, char *dn ));
32 static long msg_size LDAP_P(( LDAPMessage *msg ));
33 static void check_cache_memused LDAP_P(( LDAPCache *lc ));
34 static void uncache_entry_or_req LDAP_P(( LDAP *ld, char *dn, int msgid ));
39 ldap_enable_cache( LDAP *ld, long timeout, long maxmem )
42 if ( ld->ld_cache == NULLLDCACHE ) {
43 if (( ld->ld_cache = (LDAPCache *)malloc( sizeof( LDAPCache )))
45 ld->ld_errno = LDAP_NO_MEMORY;
48 (void) memset( ld->ld_cache, 0, sizeof( LDAPCache ));
49 ld->ld_cache->lc_memused = sizeof( LDAPCache );
52 ld->ld_cache->lc_timeout = timeout;
53 ld->ld_cache->lc_maxmem = maxmem;
54 check_cache_memused( ld->ld_cache );
55 ld->ld_cache->lc_enabled = 1;
64 ldap_disable_cache( LDAP *ld )
67 if ( ld->ld_cache != NULLLDCACHE ) {
68 ld->ld_cache->lc_enabled = 0;
76 ldap_set_cache_options( LDAP *ld, unsigned long opts )
79 if ( ld->ld_cache != NULLLDCACHE ) {
80 ld->ld_cache->lc_options = opts;
87 ldap_destroy_cache( LDAP *ld )
90 if ( ld->ld_cache != NULLLDCACHE ) {
91 ldap_flush_cache( ld );
92 free( (char *)ld->ld_cache );
93 ld->ld_cache = NULLLDCACHE;
100 ldap_flush_cache( LDAP *ld )
104 LDAPMessage *m, *next;
106 Debug( LDAP_DEBUG_TRACE, "ldap_flush_cache\n", 0, 0, 0 );
108 if ( ld->ld_cache != NULLLDCACHE ) {
109 /* delete all requests in the queue */
110 for ( m = ld->ld_cache->lc_requests; m != NULLMSG; m = next ) {
114 ld->ld_cache->lc_requests = NULLMSG;
116 /* delete all messages in the cache */
117 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
118 for ( m = ld->ld_cache->lc_buckets[ i ];
119 m != NULLMSG; m = next ) {
123 ld->ld_cache->lc_buckets[ i ] = NULLMSG;
125 ld->ld_cache->lc_memused = sizeof( LDAPCache );
132 ldap_uncache_request( LDAP *ld, int msgid )
135 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_request %d ld_cache %lx\n",
136 msgid, (long) ld->ld_cache, 0 );
138 uncache_entry_or_req( ld, NULL, msgid );
144 ldap_uncache_entry( LDAP *ld, char *dn )
147 Debug( LDAP_DEBUG_TRACE, "ldap_uncache_entry %s ld_cache %lx\n",
148 dn, (long) ld->ld_cache, 0 );
150 uncache_entry_or_req( ld, dn, 0 );
158 uncache_entry_or_req( LDAP *ld,
159 char *dn, /* if non-NULL, uncache entry */
160 int msgid ) /* request to uncache (if dn == NULL) */
163 LDAPMessage *m, *prev, *next;
165 Debug( LDAP_DEBUG_TRACE,
166 "ldap_uncache_entry_or_req dn %s msgid %d ld_cache %lx\n",
167 dn, msgid, (long) ld->ld_cache );
169 if ( ld->ld_cache == NULLLDCACHE ) {
173 /* first check the request queue */
175 for ( m = ld->ld_cache->lc_requests; m != NULLMSG; m = next ) {
177 if (( dn != NULL && chain_contains_dn( m, dn )) ||
178 ( dn == NULL && m->lm_msgid == msgid )) {
179 if ( prev == NULLMSG ) {
180 ld->ld_cache->lc_requests = next;
182 prev->lm_next = next;
184 ld->ld_cache->lc_memused -= msg_size( m );
191 /* now check the rest of the cache */
192 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
194 for ( m = ld->ld_cache->lc_buckets[ i ]; m != NULLMSG;
197 if (( dn != NULL && chain_contains_dn( m, dn )) ||
198 ( dn == NULL && m->lm_msgid == msgid )) {
199 if ( prev == NULLMSG ) {
200 ld->ld_cache->lc_buckets[ i ] = next;
202 prev->lm_next = next;
204 ld->ld_cache->lc_memused -= msg_size( m );
216 ldap_add_request_to_cache( LDAP *ld, unsigned long msgtype, BerElement *request )
222 Debug( LDAP_DEBUG_TRACE, "ldap_add_request_to_cache\n", 0, 0, 0 );
224 ld->ld_errno = LDAP_SUCCESS;
225 if ( ld->ld_cache == NULLLDCACHE ||
226 ( ld->ld_cache->lc_enabled == 0 )) {
230 if (( new = (LDAPMessage *) calloc( 1, sizeof(LDAPMessage) ))
232 if (( new->lm_ber = ldap_alloc_ber_with_options( ld )) == NULLBER ) {
236 len = request->ber_ptr - request->ber_buf;
237 if (( new->lm_ber->ber_buf = (char *) malloc( (size_t)len ))
239 ber_free( new->lm_ber, 0 );
241 ld->ld_errno = LDAP_NO_MEMORY;
244 SAFEMEMCPY( new->lm_ber->ber_buf, request->ber_buf,
246 new->lm_ber->ber_ptr = new->lm_ber->ber_buf;
247 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
248 new->lm_msgid = ld->ld_msgid;
249 new->lm_msgtype = msgtype;;
250 new->lm_next = ld->ld_cache->lc_requests;
251 ld->ld_cache->lc_requests = new;
253 ld->ld_errno = LDAP_NO_MEMORY;
260 ldap_add_result_to_cache( LDAP *ld, LDAPMessage *result )
263 LDAPMessage *m, **mp, *req, *new, *prev;
266 Debug( LDAP_DEBUG_TRACE, "ldap_add_result_to_cache: id %d, type %d\n",
267 result->lm_msgid, result->lm_msgtype, 0 );
269 if ( ld->ld_cache == NULLLDCACHE ||
270 ( ld->ld_cache->lc_enabled == 0 )) {
271 Debug( LDAP_DEBUG_TRACE, "artc: cache disabled\n", 0, 0, 0 );
275 if ( result->lm_msgtype != LDAP_RES_SEARCH_ENTRY &&
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 != NULLMSG ) { /* found request; add to end of chain */
301 for ( ; m->lm_chain != NULLMSG; m = m->lm_chain )
303 if (( new = msg_dup( result )) != NULLMSG ) {
304 new->lm_chain = NULLMSG;
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 == NULLMSG ) {
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, unsigned long msgtype, BerElement *request )
378 LDAPMessage *m, *new, *prev, *next;
381 unsigned long validtime;
383 Debug( LDAP_DEBUG_TRACE, "ldap_check_cache\n", 0, 0, 0 );
385 if ( ld->ld_cache == NULLLDCACHE ||
386 ( ld->ld_cache->lc_enabled == 0 )) {
390 reqber.ber_buf = reqber.ber_ptr = request->ber_buf;
391 reqber.ber_end = request->ber_ptr;
393 validtime = (long)time( NULL ) - ld->ld_cache->lc_timeout;
396 hash = cache_hash( &reqber );
397 for ( m = ld->ld_cache->lc_buckets[ hash ]; m != NULLMSG; m = next ) {
398 Debug( LDAP_DEBUG_TRACE,"cc: examining id %d,type %d\n",
399 m->lm_msgid, m->lm_msgtype, 0 );
400 if ( m->lm_time < validtime ) {
401 /* delete expired message */
403 if ( prev == NULL ) {
404 ld->ld_cache->lc_buckets[ hash ] = next;
406 prev->lm_next = next;
408 Debug( LDAP_DEBUG_TRACE, "cc: expired id %d\n",
410 ld->ld_cache->lc_memused -= msg_size( m );
413 if ( m->lm_msgtype == (int)msgtype &&
414 request_cmp( m->lm_ber, &reqber ) == 0 ) {
422 if ( m == NULLMSG ) {
427 * add duplicates of responses to incoming queue
430 for ( m = m->lm_chain; m != NULLMSG; m = m->lm_chain ) {
431 if (( new = msg_dup( m )) == NULLMSG ) {
435 new->lm_msgid = ld->ld_msgid;
436 new->lm_chain = NULLMSG;
438 new->lm_next = ld->ld_responses;
439 ld->ld_responses = new;
442 prev->lm_chain = new;
445 Debug( LDAP_DEBUG_TRACE, "cc: added type %d\n",
446 new->lm_msgtype, 0, 0 );
449 Debug( LDAP_DEBUG_TRACE, "cc: result returned from cache\n", 0, 0, 0 );
459 cache_hash( BerElement *ber )
465 * just take the length of the packet and mod with # of buckets
468 if ( ber_skip_tag( &bercpy, &len ) == LBER_ERROR
469 || ber_scanf( &bercpy, "x" ) == LBER_ERROR ) {
470 len = 0; /* punt: just return zero */
472 len = bercpy.ber_end - bercpy.ber_ptr;
475 Debug( LDAP_DEBUG_TRACE, "cache_hash: len is %ld, returning %ld\n",
476 len, len % LDAP_CACHE_BUCKETS, 0 );
477 return( (int) ( len % LDAP_CACHE_BUCKETS ));
482 msg_dup( LDAPMessage *msg )
487 if (( new = (LDAPMessage *)malloc( sizeof(LDAPMessage))) != NULL ) {
488 *new = *msg; /* struct copy */
489 if (( new->lm_ber = ber_dup( msg->lm_ber )) == NULLBER ) {
493 len = msg->lm_ber->ber_end - msg->lm_ber->ber_buf;
494 if (( new->lm_ber->ber_buf = (char *) malloc(
495 (size_t)len )) == NULL ) {
496 ber_free( new->lm_ber, 0 );
500 SAFEMEMCPY( new->lm_ber->ber_buf, msg->lm_ber->ber_buf,
502 new->lm_ber->ber_ptr = new->lm_ber->ber_buf +
503 ( msg->lm_ber->ber_ptr - msg->lm_ber->ber_buf );
504 new->lm_ber->ber_end = new->lm_ber->ber_buf + len;
512 request_cmp( BerElement *req1, BerElement *req2 )
517 r1 = *req1; /* struct copies */
521 * skip the enclosing tags (sequence markers) and the msg ids
523 if ( ber_skip_tag( &r1, &len ) == LBER_ERROR || ber_scanf( &r1, "x" )
527 if ( ber_skip_tag( &r2, &len ) == LBER_ERROR || ber_scanf( &r2, "x" )
533 * check remaining length and bytes if necessary
535 if (( len = r1.ber_end - r1.ber_ptr ) !=
536 (unsigned long) (r2.ber_end - r2.ber_ptr) )
538 return( -1 ); /* different lengths */
540 return( memcmp( r1.ber_ptr, r2.ber_ptr, (size_t)len ));
545 chain_contains_dn( LDAPMessage *msg, char *dn )
555 * first check the base or dn of the request
557 ber = *msg->lm_ber; /* struct copy */
558 if ( ber_scanf( &ber, "{i{a", &msgid, &s ) != LBER_ERROR ) {
559 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
566 if ( msg->lm_msgtype == LDAP_REQ_COMPARE ) {
571 * now check the dn of each search result
574 for ( m = msg->lm_chain; m != NULLMSG && rc == 0 ; m = m->lm_chain ) {
575 if ( m->lm_msgtype != LDAP_RES_SEARCH_ENTRY ) {
578 ber = *m->lm_ber; /* struct copy */
579 if ( ber_scanf( &ber, "{a", &s ) != LBER_ERROR ) {
580 rc = ( strcasecmp( dn, s ) == 0 ) ? 1 : 0;
590 msg_size( LDAPMessage *msg )
596 for ( m = msg; m != NULLMSG; m = m->lm_chain ) {
597 size += ( sizeof( LDAPMessage ) + m->lm_ber->ber_end -
598 m->lm_ber->ber_buf );
605 #define THRESHOLD_FACTOR 3 / 4
606 #define SIZE_FACTOR 2 / 3
609 check_cache_memused( LDAPCache *lc )
612 * this routine is called to check if the cache is too big (lc_maxmem >
613 * minimum cache size and lc_memused > lc_maxmem). If too big, it reduces
614 * the cache size to < SIZE_FACTOR * lc_maxmem. The algorithm is as follows:
615 * remove_threshold = lc_timeout seconds;
617 * remove everything older than remove_threshold seconds;
618 * remove_threshold = remove_threshold * THRESHOLD_FACTOR;
619 * } while ( cache size is > SIZE_FACTOR * lc_maxmem )
622 unsigned long remove_threshold, validtime;
623 LDAPMessage *m, *prev, *next;
625 Debug( LDAP_DEBUG_TRACE, "check_cache_memused: %ld bytes in use (%ld max)\n",
626 lc->lc_memused, lc->lc_maxmem, 0 );
628 if ( lc->lc_maxmem <= sizeof( LDAPCache )
629 || lc->lc_memused <= lc->lc_maxmem * SIZE_FACTOR ) {
633 remove_threshold = lc->lc_timeout;
634 while ( lc->lc_memused > lc->lc_maxmem * SIZE_FACTOR ) {
635 validtime = (long)time( NULL ) - remove_threshold;
636 for ( i = 0; i < LDAP_CACHE_BUCKETS; ++i ) {
638 for ( m = lc->lc_buckets[ i ]; m != NULLMSG;
641 if ( m->lm_time < validtime ) {
642 if ( prev == NULLMSG ) {
643 lc->lc_buckets[ i ] = next;
645 prev->lm_next = next;
647 lc->lc_memused -= msg_size( m );
648 Debug( LDAP_DEBUG_TRACE,
657 remove_threshold *= THRESHOLD_FACTOR;
660 Debug( LDAP_DEBUG_TRACE, "ccm: reduced usage to %ld bytes\n",
661 lc->lc_memused, 0, 0 );
664 #endif /* !NO_CACHE */