source3/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         /* I leave it for now, though I don't think we really
  49          * need this (mimir, 27.09.2002) */
  50         DEBUG(5, ("namecache_enable: enabling netbios namecache, timeout %d "
  51                   "seconds\n", lp_name_cache_timeout()));
  52
  53         return True;
  54 }
  55
  56 /**
  57  * Generates a key for netbios name lookups on basis of
  58  * netbios name and type.
  59  * The caller must free returned key string when finished.
  60  *
  61  * @param name netbios name string (case insensitive)
  62  * @param name_type netbios type of the name being looked up
  63  *
  64  * @return string consisted of uppercased name and appended
  65  *         type number
  66  */
  67
  68 static char* namecache_key(const char *name,
  69                                 int name_type)
  70 {
  71         char *keystr;
  72         asprintf_strupper_m(&keystr, NBTKEY_FMT, name, name_type);
  73
  74         return keystr;
  75 }
  76
  77 /**
  78  * Store a name(s) in the name cache
  79  *
  80  * @param name netbios names array
  81  * @param name_type integer netbios name type
  82  * @param num_names number of names being stored
  83  * @param ip_list array of in_addr structures containing
  84  *        ip addresses being stored
  85  **/
  86
  87 bool namecache_store(const char *name,
  88                         int name_type,
  89                         int num_names,
  90                         struct ip_service *ip_list)
  91 {
  92         time_t expiry;
  93         char *key, *value_string;
  94         int i;
  95         bool ret;
  96
  97         if (name_type > 255) {
  98                 return False; /* Don't store non-real name types. */
  99         }
 100
 101         if ( DEBUGLEVEL >= 5 ) {
 102                 TALLOC_CTX *ctx = talloc_stackframe();
 103                 char *addr = NULL;
 104
 105                 DEBUG(5, ("namecache_store: storing %d address%s for %s#%02x: ",
 106                         num_names, num_names == 1 ? "": "es", name, name_type));
 107
 108                 for (i = 0; i < num_names; i++) {
 109                         addr = print_canonical_sockaddr(ctx,
 110                                                         &ip_list[i].ss);
 111                         if (!addr) {
 112                                 continue;
 113                         }
 114                         DEBUGADD(5, ("%s%s", addr,
 115                                 (i == (num_names - 1) ? "" : ",")));
 116
 117                 }
 118                 DEBUGADD(5, ("\n"));
 119                 TALLOC_FREE(ctx);
 120         }
 121
 122         key = namecache_key(name, name_type);
 123         if (!key) {
 124                 return False;
 125         }
 126
 127         expiry = time(NULL) + lp_name_cache_timeout();
 128
 129         /*
 130          * Generate string representation of ip addresses list
 131          * First, store the number of ip addresses and then
 132          * place each single ip
 133          */
 134         if (!ipstr_list_make(&value_string, ip_list, num_names)) {
 135                 SAFE_FREE(key);
 136                 SAFE_FREE(value_string);
 137                 return false;
 138         }
 139
 140         /* set the entry */
 141         ret = gencache_set(key, value_string, expiry);
 142         SAFE_FREE(key);
 143         SAFE_FREE(value_string);
 144         return ret;
 145 }
 146
 147 /**
 148  * Look up a name in the cache.
 149  *
 150  * @param name netbios name to look up for
 151  * @param name_type netbios name type of @param name
 152  * @param ip_list mallocated list of IP addresses if found in the cache,
 153  *        NULL otherwise
 154  * @param num_names number of entries found
 155  *
 156  * @return true upon successful fetch or
 157  *         false if name isn't found in the cache or has expired
 158  **/
 159
 160 bool namecache_fetch(const char *name,
 161                         int name_type,
 162                         struct ip_service **ip_list,
 163                         int *num_names)
 164 {
 165         char *key, *value;
 166         time_t timeout;
 167
 168         /* exit now if null pointers were passed as they're required further */
 169         if (!ip_list || !num_names) {
 170                 return False;
 171         }
 172
 173         if (name_type > 255) {
 174                 return False; /* Don't fetch non-real name types. */
 175         }
 176
 177         *num_names = 0;
 178
 179         /*
 180          * Use gencache interface - lookup the key
 181          */
 182         key = namecache_key(name, name_type);
 183         if (!key) {
 184                 return False;
 185         }
 186
 187         if (!gencache_get(key, &value, &timeout)) {
 188                 DEBUG(5, ("no entry for %s#%02X found.\n", name, name_type));
 189                 SAFE_FREE(key);
 190                 return False;
 191         } else {
 192                 DEBUG(5, ("name %s#%02X found.\n", name, name_type));
 193         }
 194
 195         /*
 196          * Split up the stored value into the list of IP adresses
 197          */
 198         *num_names = ipstr_list_parse(value, ip_list);
 199
 200         SAFE_FREE(key);
 201         SAFE_FREE(value);
 202
 203         return *num_names > 0; /* true only if some ip has been fetched */
 204 }
 205
 206 /**
 207  * Remove a namecache entry. Needed for site support.
 208  *
 209  **/
 210
 211 bool namecache_delete(const char *name, int name_type)
 212 {
 213         bool ret;
 214         char *key;
 215
 216         if (name_type > 255) {
 217                 return False; /* Don't fetch non-real name types. */
 218         }
 219
 220         key = namecache_key(name, name_type);
 221         if (!key) {
 222                 return False;
 223         }
 224         ret = gencache_del(key);
 225         SAFE_FREE(key);
 226         return ret;
 227 }
 228
 229 /**
 230  * Delete single namecache entry. Look at the
 231  * gencache_iterate definition.
 232  *
 233  **/
 234
 235 static void flush_netbios_name(const char *key,
 236                         const char *value,
 237                         time_t timeout,
 238                         void *dptr)
 239 {
 240         gencache_del(key);
 241         DEBUG(5, ("Deleting entry %s\n", key));
 242 }
 243
 244 /**
 245  * Flush all names from the name cache.
 246  * It's done by gencache_iterate()
 247  *
 248  * @return true upon successful deletion or
 249  *         false in case of an error
 250  **/
 251
 252 void namecache_flush(void)
 253 {
 254         /*
 255          * iterate through each NBT cache's entry and flush it
 256          * by flush_netbios_name function
 257          */
 258         gencache_iterate(flush_netbios_name, NULL, "NBT/*");
 259         DEBUG(5, ("Namecache flushed\n"));
 260 }
 261
 262 /* Construct a name status record key. */
 263
 264 static char *namecache_status_record_key(const char *name,
 265                                 int name_type1,
 266                                 int name_type2,
 267                                 const struct sockaddr_storage *keyip)
 268 {
 269         char addr[INET6_ADDRSTRLEN];
 270         char *keystr;
 271
 272         print_sockaddr(addr, sizeof(addr), keyip);
 273         asprintf_strupper_m(&keystr, "NBT/%s#%02X.%02X.%s", name,
 274                             name_type1, name_type2, addr);
 275         return keystr;
 276 }
 277
 278 /* Store a name status record. */
 279
 280 bool namecache_status_store(const char *keyname, int keyname_type,
 281                 int name_type, const struct sockaddr_storage *keyip,
 282                 const char *srvname)
 283 {
 284         char *key;
 285         time_t expiry;
 286         bool ret;
 287
 288         key = namecache_status_record_key(keyname, keyname_type,
 289                         name_type, keyip);
 290         if (!key)
 291                 return False;
 292
 293         expiry = time(NULL) + lp_name_cache_timeout();
 294         ret = gencache_set(key, srvname, expiry);
 295
 296         if (ret) {
 297                 DEBUG(5, ("namecache_status_store: entry %s -> %s\n",
 298                                         key, srvname ));
 299         } else {
 300                 DEBUG(5, ("namecache_status_store: entry %s store failed.\n",
 301                                         key ));
 302         }
 303
 304         SAFE_FREE(key);
 305         return ret;
 306 }
 307
 308 /* Fetch a name status record. */
 309
 310 bool namecache_status_fetch(const char *keyname,
 311                                 int keyname_type,
 312                                 int name_type,
 313                                 const struct sockaddr_storage *keyip,
 314                                 char *srvname_out)
 315 {
 316         char *key = NULL;
 317         char *value = NULL;
 318         time_t timeout;
 319
 320         key = namecache_status_record_key(keyname, keyname_type,
 321                         name_type, keyip);
 322         if (!key)
 323                 return False;
 324
 325         if (!gencache_get(key, &value, &timeout)) {
 326                 DEBUG(5, ("namecache_status_fetch: no entry for %s found.\n",
 327                                         key));
 328                 SAFE_FREE(key);
 329                 return False;
 330         } else {
 331                 DEBUG(5, ("namecache_status_fetch: key %s -> %s\n",
 332                                         key, value ));
 333         }
 334
 335         strlcpy(srvname_out, value, 16);
 336         SAFE_FREE(key);
 337         SAFE_FREE(value);
 338         return True;
 339 }