source/libsmb/namecache.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    NetBIOS name cache module on top of gencache mechanism.
   5
   6    Copyright (C) Tim Potter         2002
   7    Copyright (C) Rafal Szczesniak   2002
   8    Copyright (C) Jeremy Allison     2007
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25
  26 #define NBTKEY_FMT  "NBT/%s#%02X"
  27
  28 /**
  29  * Initialise namecache system. Function calls gencache
  30  * initialisation function to perform necessary actions
  31  *
  32  * @return true upon successful initialisation of the cache or
  33  *         false on failure
  34  **/
  35
  36 bool namecache_enable(void)
  37 {
  38         /*
  39          * Check if name caching disabled by setting the name cache
  40          * timeout to zero.
  41          */
  42
  43         if (lp_name_cache_timeout() == 0) {
  44                 DEBUG(5, ("namecache_enable: disabling netbios name cache\n"));
  45                 return False;
  46         }
  47
  48         /* Init namecache by calling gencache initialisation */
  49
  50         if (!gencache_init()) {
  51                 DEBUG(2, ("namecache_enable: "
  52                         "Couldn't initialise namecache on top of gencache.\n"));
  53                 return False;
  54         }
  55
  56         /* I leave it for now, though I don't think we really
  57          * need this (mimir, 27.09.2002) */
  58         DEBUG(5, ("namecache_enable: enabling netbios namecache, timeout %d "
  59                   "seconds\n", lp_name_cache_timeout()));
  60
  61         return True;
  62 }
  63
  64 /**
  65  * Shutdown namecache. Routine calls gencache close function
  66  * to safely close gencache file.
  67  *
  68  * @return true upon successful shutdown of the cache or
  69  *         false on failure
  70  **/
  71
  72 bool namecache_shutdown(void)
  73 {
  74         if (!gencache_shutdown()) {
  75                 DEBUG(2, ("namecache_shutdown: "
  76                         "Couldn't close namecache on top of gencache.\n"));
  77                 return False;
  78         }
  79
  80         DEBUG(5, ("namecache_shutdown: "
  81                 "netbios namecache closed successfully.\n"));
  82         return True;
  83 }
  84
  85 /**
  86  * Generates a key for netbios name lookups on basis of
  87  * netbios name and type.
  88  * The caller must free returned key string when finished.
  89  *
  90  * @param name netbios name string (case insensitive)
  91  * @param name_type netbios type of the name being looked up
  92  *
  93  * @return string consisted of uppercased name and appended
  94  *         type number
  95  */
  96
  97 static char* namecache_key(const char *name,
  98                                 int name_type)
  99 {
 100         char *keystr;
 101         asprintf_strupper_m(&keystr, NBTKEY_FMT, name, name_type);
 102
 103         return keystr;
 104 }
 105
 106 /**
 107  * Store a name(s) in the name cache
 108  *
 109  * @param name netbios names array
 110  * @param name_type integer netbios name type
 111  * @param num_names number of names being stored
 112  * @param ip_list array of in_addr structures containing
 113  *        ip addresses being stored
 114  **/
 115
 116 bool namecache_store(const char *name,
 117                         int name_type,
 118                         int num_names,
 119                         struct ip_service *ip_list)
 120 {
 121         time_t expiry;
 122         char *key, *value_string;
 123         int i;
 124         bool ret;
 125
 126         /*
 127          * we use gecache call to avoid annoying debug messages about
 128          * initialised namecache again and again...
 129          */
 130         if (!gencache_init()) {
 131                 return False;
 132         }
 133
 134         if (name_type > 255) {
 135                 return False; /* Don't store non-real name types. */
 136         }
 137
 138         if ( DEBUGLEVEL >= 5 ) {
 139                 TALLOC_CTX *ctx = talloc_stackframe();
 140                 char *addr = NULL;
 141
 142                 DEBUG(5, ("namecache_store: storing %d address%s for %s#%02x: ",
 143                         num_names, num_names == 1 ? "": "es", name, name_type));
 144
 145                 for (i = 0; i < num_names; i++) {
 146                         addr = print_canonical_sockaddr(ctx,
 147                                                         &ip_list[i].ss);
 148                         if (!addr) {
 149                                 continue;
 150                         }
 151                         DEBUGADD(5, ("%s%s", addr,
 152                                 (i == (num_names - 1) ? "" : ",")));
 153
 154                 }
 155                 DEBUGADD(5, ("\n"));
 156                 TALLOC_FREE(ctx);
 157         }
 158
 159         key = namecache_key(name, name_type);
 160         if (!key) {
 161                 return False;
 162         }
 163
 164         expiry = time(NULL) + lp_name_cache_timeout();
 165
 166         /*
 167          * Generate string representation of ip addresses list
 168          * First, store the number of ip addresses and then
 169          * place each single ip
 170          */
 171         if (!ipstr_list_make(&value_string, ip_list, num_names)) {
 172                 SAFE_FREE(key);
 173                 SAFE_FREE(value_string);
 174                 return false;
 175         }
 176
 177         /* set the entry */
 178         ret = gencache_set(key, value_string, expiry);
 179         SAFE_FREE(key);
 180         SAFE_FREE(value_string);
 181         return ret;
 182 }
 183
 184 /**
 185  * Look up a name in the cache.
 186  *
 187  * @param name netbios name to look up for
 188  * @param name_type netbios name type of @param name
 189  * @param ip_list mallocated list of IP addresses if found in the cache,
 190  *        NULL otherwise
 191  * @param num_names number of entries found
 192  *
 193  * @return true upon successful fetch or
 194  *         false if name isn't found in the cache or has expired
 195  **/
 196
 197 bool namecache_fetch(const char *name,
 198                         int name_type,
 199                         struct ip_service **ip_list,
 200                         int *num_names)
 201 {
 202         char *key, *value;
 203         time_t timeout;
 204
 205         /* exit now if null pointers were passed as they're required further */
 206         if (!ip_list || !num_names) {
 207                 return False;
 208         }
 209
 210         if (!gencache_init()) {
 211                 return False;
 212         }
 213
 214         if (name_type > 255) {
 215                 return False; /* Don't fetch non-real name types. */
 216         }
 217
 218         *num_names = 0;
 219
 220         /*
 221          * Use gencache interface - lookup the key
 222          */
 223         key = namecache_key(name, name_type);
 224         if (!key) {
 225                 return False;
 226         }
 227
 228         if (!gencache_get(key, &value, &timeout)) {
 229                 DEBUG(5, ("no entry for %s#%02X found.\n", name, name_type));
 230                 SAFE_FREE(key);
 231                 return False;
 232         } else {
 233                 DEBUG(5, ("name %s#%02X found.\n", name, name_type));
 234         }
 235
 236         /*
 237          * Split up the stored value into the list of IP adresses
 238          */
 239         *num_names = ipstr_list_parse(value, ip_list);
 240
 241         SAFE_FREE(key);
 242         SAFE_FREE(value);
 243
 244         return *num_names > 0; /* true only if some ip has been fetched */
 245 }
 246
 247 /**
 248  * Remove a namecache entry. Needed for site support.
 249  *
 250  **/
 251
 252 bool namecache_delete(const char *name, int name_type)
 253 {
 254         bool ret;
 255         char *key;
 256
 257         if (!gencache_init())
 258                 return False;
 259
 260         if (name_type > 255) {
 261                 return False; /* Don't fetch non-real name types. */
 262         }
 263
 264         key = namecache_key(name, name_type);
 265         if (!key) {
 266                 return False;
 267         }
 268         ret = gencache_del(key);
 269         SAFE_FREE(key);
 270         return ret;
 271 }
 272
 273 /**
 274  * Delete single namecache entry. Look at the
 275  * gencache_iterate definition.
 276  *
 277  **/
 278
 279 static void flush_netbios_name(const char *key,
 280                         const char *value,
 281                         time_t timeout,
 282                         void *dptr)
 283 {
 284         gencache_del(key);
 285         DEBUG(5, ("Deleting entry %s\n", key));
 286 }
 287
 288 /**
 289  * Flush all names from the name cache.
 290  * It's done by gencache_iterate()
 291  *
 292  * @return true upon successful deletion or
 293  *         false in case of an error
 294  **/
 295
 296 void namecache_flush(void)
 297 {
 298         if (!gencache_init()) {
 299                 return;
 300         }
 301
 302         /*
 303          * iterate through each NBT cache's entry and flush it
 304          * by flush_netbios_name function
 305          */
 306         gencache_iterate(flush_netbios_name, NULL, "NBT/*");
 307         DEBUG(5, ("Namecache flushed\n"));
 308 }
 309
 310 /* Construct a name status record key. */
 311
 312 static char *namecache_status_record_key(const char *name,
 313                                 int name_type1,
 314                                 int name_type2,
 315                                 const struct sockaddr_storage *keyip)
 316 {
 317         char addr[INET6_ADDRSTRLEN];
 318         char *keystr;
 319
 320         print_sockaddr(addr, sizeof(addr), keyip);
 321         asprintf_strupper_m(&keystr, "NBT/%s#%02X.%02X.%s", name,
 322                             name_type1, name_type2, addr);
 323         return keystr;
 324 }
 325
 326 /* Store a name status record. */
 327
 328 bool namecache_status_store(const char *keyname, int keyname_type,
 329                 int name_type, const struct sockaddr_storage *keyip,
 330                 const char *srvname)
 331 {
 332         char *key;
 333         time_t expiry;
 334         bool ret;
 335
 336         if (!gencache_init()) {
 337                 return False;
 338         }
 339
 340         key = namecache_status_record_key(keyname, keyname_type,
 341                         name_type, keyip);
 342         if (!key)
 343                 return False;
 344
 345         expiry = time(NULL) + lp_name_cache_timeout();
 346         ret = gencache_set(key, srvname, expiry);
 347
 348         if (ret) {
 349                 DEBUG(5, ("namecache_status_store: entry %s -> %s\n",
 350                                         key, srvname ));
 351         } else {
 352                 DEBUG(5, ("namecache_status_store: entry %s store failed.\n",
 353                                         key ));
 354         }
 355
 356         SAFE_FREE(key);
 357         return ret;
 358 }
 359
 360 /* Fetch a name status record. */
 361
 362 bool namecache_status_fetch(const char *keyname,
 363                                 int keyname_type,
 364                                 int name_type,
 365                                 const struct sockaddr_storage *keyip,
 366                                 char *srvname_out)
 367 {
 368         char *key = NULL;
 369         char *value = NULL;
 370         time_t timeout;
 371
 372         if (!gencache_init())
 373                 return False;
 374
 375         key = namecache_status_record_key(keyname, keyname_type,
 376                         name_type, keyip);
 377         if (!key)
 378                 return False;
 379
 380         if (!gencache_get(key, &value, &timeout)) {
 381                 DEBUG(5, ("namecache_status_fetch: no entry for %s found.\n",
 382                                         key));
 383                 SAFE_FREE(key);
 384                 return False;
 385         } else {
 386                 DEBUG(5, ("namecache_status_fetch: key %s -> %s\n",
 387                                         key, value ));
 388         }
 389
 390         strlcpy(srvname_out, value, 16);
 391         SAFE_FREE(key);
 392         SAFE_FREE(value);
 393         return True;
 394 }