source3/libsmb/trustdom_cache.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Trusted domain names cache on top of gencache.
   5
   6    Copyright (C) Rafal Szczesniak       2002
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 #undef DBGC_CLASS
  26 #define DBGC_CLASS DBGC_ALL     /* there's no proper class yet */
  27
  28 #define TDOMKEY_FMT  "TDOM/%s"
  29 #define TDOMTSKEY    "TDOMCACHE/TIMESTAMP"
  30
  31
  32 /**
  33  * @file trustdom_cache.c
  34  *
  35  * Implementation of trusted domain names cache useful when
  36  * samba acts as domain member server. In such case, caching
  37  * domain names currently trusted gives a performance gain
  38  * because there's no need to query PDC each time we need
  39  * list of trusted domains
  40  **/
  41
  42
  43 /**
  44  * Initialise trustdom name caching system. Call gencache
  45  * initialisation routine to perform necessary activities.
  46  *
  47  * @return true upon successful cache initialisation or
  48  *         false if cache init failed
  49  **/
  50
  51 BOOL trustdom_cache_enable(void)
  52 {
  53         /* Init trustdom cache by calling gencache initialisation */
  54         if (!gencache_init()) {
  55                 DEBUG(2, ("trustdomcache_enable: Couldn't initialise trustdom cache on top of gencache.\n"));
  56                 return False;
  57         }
  58
  59         return True;
  60 }
  61
  62
  63 /**
  64  * Shutdown trustdom name caching system. Calls gencache
  65  * shutdown function.
  66  *
  67  * @return true upon successful cache close or
  68  *         false if it failed
  69  **/
  70
  71 BOOL trustdom_cache_shutdown(void)
  72 {
  73         /* Close trustdom cache by calling gencache shutdown */
  74         if (!gencache_shutdown()) {
  75                 DEBUG(2, ("trustdomcache_shutdown: Couldn't shutdown trustdom cache on top of gencache.\n"));
  76                 return False;
  77         }
  78
  79         return True;
  80 }
  81
  82
  83 /**
  84  * Form up trustdom name key. It is based only
  85  * on domain name now.
  86  *
  87  * @param name trusted domain name
  88  * @return cache key for use in gencache mechanism
  89  **/
  90
  91 static char* trustdom_cache_key(const char* name)
  92 {
  93         char* keystr = NULL;
  94         asprintf(&keystr, TDOMKEY_FMT, strupper_static(name));
  95
  96         return keystr;
  97 }
  98
  99
 100 /**
 101  * Store trusted domain in gencache as the domain name (key)
 102  * and ip address of domain controller (value)
 103  *
 104  * @param name trusted domain name
 105  * @param alt_name alternative trusted domain name (used in ADS domains)
 106  * @param sid trusted domain's SID
 107  * @param timeout cache entry expiration time
 108  * @return true upon successful value storing or
 109  *         false if store attempt failed
 110  **/
 111
 112 BOOL trustdom_cache_store(char* name, char* alt_name, const DOM_SID *sid,
 113                           time_t timeout)
 114 {
 115         char *key, *alt_key;
 116         fstring sid_string;
 117
 118         /*
 119          * we use gecache call to avoid annoying debug messages
 120          * about initialised trustdom
 121          */
 122         if (!gencache_init()) return False;
 123
 124         DEBUG(5, ("trustdom_store: storing SID %s of domain %s\n",
 125                   sid_string_static(sid), name));
 126
 127         key = trustdom_cache_key(name);
 128         alt_key = alt_name ? trustdom_cache_key(alt_name) : NULL;
 129
 130         /* Generate string representation domain SID */
 131         sid_to_string(sid_string, sid);
 132
 133         /*
 134          * try to put the names in the cache
 135          */
 136         if (alt_key) {
 137                 return (gencache_set(alt_key, sid_string, timeout)
 138                         && gencache_set(key, sid_string, timeout));
 139         }
 140
 141         return gencache_set(key, sid_string, timeout);
 142 }
 143
 144
 145 /**
 146  * Fetch trusted domain's dc from the gencache.
 147  * This routine can also be used to check whether given
 148  * domain is currently trusted one.
 149  *
 150  * @param name trusted domain name
 151  * @param sid trusted domain's SID to be returned
 152  * @return true if entry is found or
 153  *         false if has expired/doesn't exist
 154  **/
 155
 156 BOOL trustdom_cache_fetch(const char* name, DOM_SID* sid)
 157 {
 158         char *key, *value;
 159         time_t timeout;
 160
 161         /* init the cache */
 162         if (!gencache_init()) return False;
 163
 164         /* exit now if null pointers were passed as they're required further */
 165         if (!sid) return False;
 166
 167         /* prepare a key and get the value */
 168         key = trustdom_cache_key(name);
 169         if (!key) return False;
 170
 171         if (!gencache_get(key, &value, &timeout)) {
 172                 DEBUG(5, ("no entry for trusted domain %s found.\n", name));
 173                 SAFE_FREE(key);
 174                 return False;
 175         } else {
 176                 SAFE_FREE(key);
 177                 DEBUG(5, ("trusted domain %s found (%s)\n", name, value));
 178         }
 179
 180         /* convert ip string representation into in_addr structure */
 181         if(! string_to_sid(sid, value)) {
 182                 sid = NULL;
 183                 return False;
 184         }
 185
 186         return True;
 187 }
 188
 189
 190 /*******************************************************************
 191  fetch the timestamp from the last update
 192 *******************************************************************/
 193
 194 uint32 trustdom_cache_fetch_timestamp( void )
 195 {
 196         char *value;
 197         time_t timeout;
 198         uint32 timestamp;
 199
 200         /* init the cache */
 201         if (!gencache_init())
 202                 return False;
 203
 204         if (!gencache_get(TDOMTSKEY, &value, &timeout)) {
 205                 DEBUG(5, ("no timestamp for trusted domain cache located.\n"));
 206                 return 0;
 207         }
 208
 209         timestamp = atoi(value);
 210
 211         return timestamp;
 212 }
 213
 214 /*******************************************************************
 215  store the timestamp from the last update
 216 *******************************************************************/
 217
 218 BOOL trustdom_cache_store_timestamp( uint32 t, time_t timeout )
 219 {
 220         fstring value;
 221
 222         /* init the cache */
 223         if (!gencache_init())
 224                 return False;
 225
 226         fstr_sprintf(value, "%d", t );
 227
 228         if (!gencache_set(TDOMTSKEY, value, timeout)) {
 229                 DEBUG(5, ("failed to set timestamp for trustdom_cache\n"));
 230                 return False;
 231         }
 232
 233         return True;
 234 }
 235
 236
 237 /*******************************************************************
 238  lock the timestamp entry in the trustdom_cache
 239 *******************************************************************/
 240
 241 BOOL trustdom_cache_lock_timestamp( void )
 242 {
 243         return gencache_lock_entry( TDOMTSKEY ) != -1;
 244 }
 245
 246 /*******************************************************************
 247  unlock the timestamp entry in the trustdom_cache
 248 *******************************************************************/
 249
 250 void trustdom_cache_unlock_timestamp( void )
 251 {
 252         gencache_unlock_entry( TDOMTSKEY );
 253 }
 254
 255 /**
 256  * Delete single trustdom entry. Look at the
 257  * gencache_iterate definition.
 258  *
 259  **/
 260
 261 static void flush_trustdom_name(const char* key, const char *value, time_t timeout, void* dptr)
 262 {
 263         gencache_del(key);
 264         DEBUG(5, ("Deleting entry %s\n", key));
 265 }
 266
 267
 268 /**
 269  * Flush all the trusted domains entries from the cache.
 270  **/
 271
 272 void trustdom_cache_flush(void)
 273 {
 274         if (!gencache_init())
 275                 return;
 276
 277         /*
 278          * iterate through each TDOM cache's entry and flush it
 279          * by flush_trustdom_name function
 280          */
 281         gencache_iterate(flush_trustdom_name, NULL, trustdom_cache_key("*"));
 282         DEBUG(5, ("Trusted domains cache flushed\n"));
 283 }
 284
 285 /********************************************************************
 286  update the trustdom_cache if needed
 287 ********************************************************************/
 288 #define TRUSTDOM_UPDATE_INTERVAL        600
 289
 290 void update_trustdom_cache( void )
 291 {
 292         char **domain_names;
 293         DOM_SID *dom_sids;
 294         uint32 num_domains;
 295         uint32 last_check;
 296         int time_diff;
 297         TALLOC_CTX *mem_ctx = NULL;
 298         time_t now = time(NULL);
 299         int i;
 300
 301         /* get the timestamp.  We have to initialise it if the last timestamp == 0 */
 302
 303         if ( (last_check = trustdom_cache_fetch_timestamp()) == 0 )
 304                 trustdom_cache_store_timestamp(0, now+TRUSTDOM_UPDATE_INTERVAL);
 305
 306         time_diff = now - last_check;
 307
 308         if ( (time_diff > 0) && (time_diff < TRUSTDOM_UPDATE_INTERVAL) ) {
 309                 DEBUG(10,("update_trustdom_cache: not time to update trustdom_cache yet\n"));
 310                 return;
 311         }
 312
 313         /* lock the timestamp */
 314         if ( !trustdom_cache_lock_timestamp() )
 315                 return;
 316
 317         if ( !(mem_ctx = talloc_init("update_trustdom_cache")) ) {
 318                 DEBUG(0,("update_trustdom_cache: talloc_init() failed!\n"));
 319                 goto done;
 320         }
 321
 322         /* get the domains and store them */
 323
 324         if ( enumerate_domain_trusts(mem_ctx, lp_workgroup(), &domain_names,
 325                 &num_domains, &dom_sids) )
 326         {
 327                 for ( i=0; i<num_domains; i++ ) {
 328                         trustdom_cache_store( domain_names[i], NULL, &dom_sids[i],
 329                                 now+TRUSTDOM_UPDATE_INTERVAL);
 330                 }
 331
 332                 trustdom_cache_store_timestamp( now, now+TRUSTDOM_UPDATE_INTERVAL );
 333         }
 334
 335 done:
 336         /* unlock and we're done */
 337         trustdom_cache_unlock_timestamp();
 338
 339         talloc_destroy( mem_ctx );
 340
 341         return;
 342 }