source/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         BOOL ret;
 118
 119         /*
 120          * we use gecache call to avoid annoying debug messages
 121          * about initialised trustdom
 122          */
 123         if (!gencache_init())
 124                 return False;
 125
 126         DEBUG(5, ("trustdom_store: storing SID %s of domain %s\n",
 127                   sid_string_static(sid), name));
 128
 129         key = trustdom_cache_key(name);
 130         alt_key = alt_name ? trustdom_cache_key(alt_name) : NULL;
 131
 132         /* Generate string representation domain SID */
 133         sid_to_string(sid_string, sid);
 134
 135         /*
 136          * try to put the names in the cache
 137          */
 138         if (alt_key) {
 139                 ret = gencache_set(alt_key, sid_string, timeout);
 140                 if ( ret ) {
 141                         ret = gencache_set(key, sid_string, timeout);
 142                 }
 143                 SAFE_FREE(alt_key);
 144                 SAFE_FREE(key);
 145                 return ret;
 146         }
 147
 148         ret = gencache_set(key, sid_string, timeout);
 149         SAFE_FREE(key);
 150         return ret;
 151 }
 152
 153
 154 /**
 155  * Fetch trusted domain's dc from the gencache.
 156  * This routine can also be used to check whether given
 157  * domain is currently trusted one.
 158  *
 159  * @param name trusted domain name
 160  * @param sid trusted domain's SID to be returned
 161  * @return true if entry is found or
 162  *         false if has expired/doesn't exist
 163  **/
 164
 165 BOOL trustdom_cache_fetch(const char* name, DOM_SID* sid)
 166 {
 167         char *key = NULL, *value = NULL;
 168         time_t timeout;
 169
 170         /* init the cache */
 171         if (!gencache_init())
 172                 return False;
 173
 174         /* exit now if null pointers were passed as they're required further */
 175         if (!sid)
 176                 return False;
 177
 178         /* prepare a key and get the value */
 179         key = trustdom_cache_key(name);
 180         if (!key)
 181                 return False;
 182
 183         if (!gencache_get(key, &value, &timeout)) {
 184                 DEBUG(5, ("no entry for trusted domain %s found.\n", name));
 185                 SAFE_FREE(key);
 186                 return False;
 187         } else {
 188                 SAFE_FREE(key);
 189                 DEBUG(5, ("trusted domain %s found (%s)\n", name, value));
 190         }
 191
 192         /* convert ip string representation into in_addr structure */
 193         if(! string_to_sid(sid, value)) {
 194                 sid = NULL;
 195                 SAFE_FREE(value);
 196                 return False;
 197         }
 198
 199         SAFE_FREE(value);
 200         return True;
 201 }
 202
 203
 204 /*******************************************************************
 205  fetch the timestamp from the last update
 206 *******************************************************************/
 207
 208 uint32 trustdom_cache_fetch_timestamp( void )
 209 {
 210         char *value = NULL;
 211         time_t timeout;
 212         uint32 timestamp;
 213
 214         /* init the cache */
 215         if (!gencache_init())
 216                 return False;
 217
 218         if (!gencache_get(TDOMTSKEY, &value, &timeout)) {
 219                 DEBUG(5, ("no timestamp for trusted domain cache located.\n"));
 220                 SAFE_FREE(value);
 221                 return 0;
 222         }
 223
 224         timestamp = atoi(value);
 225
 226         SAFE_FREE(value);
 227         return timestamp;
 228 }
 229
 230 /*******************************************************************
 231  store the timestamp from the last update
 232 *******************************************************************/
 233
 234 BOOL trustdom_cache_store_timestamp( uint32 t, time_t timeout )
 235 {
 236         fstring value;
 237
 238         /* init the cache */
 239         if (!gencache_init())
 240                 return False;
 241
 242         fstr_sprintf(value, "%d", t );
 243
 244         if (!gencache_set(TDOMTSKEY, value, timeout)) {
 245                 DEBUG(5, ("failed to set timestamp for trustdom_cache\n"));
 246                 return False;
 247         }
 248
 249         return True;
 250 }
 251
 252
 253 /**
 254  * Delete single trustdom entry. Look at the
 255  * gencache_iterate definition.
 256  *
 257  **/
 258
 259 static void flush_trustdom_name(const char* key, const char *value, time_t timeout, void* dptr)
 260 {
 261         gencache_del(key);
 262         DEBUG(5, ("Deleting entry %s\n", key));
 263 }
 264
 265
 266 /**
 267  * Flush all the trusted domains entries from the cache.
 268  **/
 269
 270 void trustdom_cache_flush(void)
 271 {
 272         if (!gencache_init())
 273                 return;
 274
 275         /*
 276          * iterate through each TDOM cache's entry and flush it
 277          * by flush_trustdom_name function
 278          */
 279         gencache_iterate(flush_trustdom_name, NULL, trustdom_cache_key("*"));
 280         DEBUG(5, ("Trusted domains cache flushed\n"));
 281 }
 282
 283 /********************************************************************
 284  update the trustdom_cache if needed
 285 ********************************************************************/
 286 #define TRUSTDOM_UPDATE_INTERVAL        600
 287
 288 void update_trustdom_cache( void )
 289 {
 290         char **domain_names;
 291         DOM_SID *dom_sids;
 292         uint32 num_domains;
 293         uint32 last_check;
 294         int time_diff;
 295         TALLOC_CTX *mem_ctx = NULL;
 296         time_t now = time(NULL);
 297         int i;
 298
 299         /* get the timestamp.  We have to initialise it if the last timestamp == 0 */
 300         if ( (last_check = trustdom_cache_fetch_timestamp()) == 0 )
 301                 trustdom_cache_store_timestamp(0, now+TRUSTDOM_UPDATE_INTERVAL);
 302
 303         time_diff = (int) (now - last_check);
 304
 305         if ( (time_diff > 0) && (time_diff < TRUSTDOM_UPDATE_INTERVAL) ) {
 306                 DEBUG(10,("update_trustdom_cache: not time to update trustdom_cache yet\n"));
 307                 return;
 308         }
 309
 310         /* note that we don't lock the timestamp. This prevents this
 311            smbd from blocking all other smbd daemons while we
 312            enumerate the trusted domains */
 313         trustdom_cache_store_timestamp(now, now+TRUSTDOM_UPDATE_INTERVAL);
 314
 315         if ( !(mem_ctx = talloc_init("update_trustdom_cache")) ) {
 316                 DEBUG(0,("update_trustdom_cache: talloc_init() failed!\n"));
 317                 goto done;
 318         }
 319
 320         /* get the domains and store them */
 321
 322         if ( enumerate_domain_trusts(mem_ctx, lp_workgroup(), &domain_names,
 323                 &num_domains, &dom_sids)) {
 324                 for ( i=0; i<num_domains; i++ ) {
 325                         trustdom_cache_store( domain_names[i], NULL, &dom_sids[i],
 326                                 now+TRUSTDOM_UPDATE_INTERVAL);
 327                 }
 328         } else {
 329                 /* we failed to fetch the list of trusted domains - restore the old
 330                    timestamp */
 331                 trustdom_cache_store_timestamp(last_check,
 332                                                last_check+TRUSTDOM_UPDATE_INTERVAL);
 333         }
 334
 335 done:
 336         talloc_destroy( mem_ctx );
 337
 338         return;
 339 }