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
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25
  26 #define NBTKEY_FMT  "NBT/%s#%02X"
  27
  28
  29 /**
  30  * Initialise namecache system. Function calls gencache
  31  * initialisation function to perform necessary actions
  32  *
  33  * @return true upon successful initialisation of the cache or
  34  *         false on failure
  35  **/
  36
  37 BOOL namecache_enable(void)
  38 {
  39         /*
  40          * Check if name caching disabled by setting the name cache
  41          * timeout to zero.
  42          */
  43
  44         if (lp_name_cache_timeout() == 0) {
  45                 DEBUG(5, ("namecache_enable: disabling netbios name cache\n"));
  46                 return False;
  47         }
  48
  49         /* Init namecache by calling gencache initialisation */
  50
  51         if (!gencache_init()) {
  52                 DEBUG(2, ("namecache_enable: 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 need this (mimir, 27.09.2002) */
  57         DEBUG(5, ("namecache_enable: enabling netbios namecache, timeout %d "
  58                   "seconds\n", lp_name_cache_timeout()));
  59
  60         return True;
  61 }
  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: Couldn't close namecache on top of gencache.\n"));
  76                 return False;
  77         }
  78
  79         DEBUG(5, ("namecache_shutdown: netbios namecache closed successfully.\n"));
  80         return True;
  81 }
  82
  83
  84 /**
  85  * Generates a key for netbios name lookups on basis of
  86  * netbios name and type.
  87  * The caller must free returned key string when finished.
  88  *
  89  * @param name netbios name string (case insensitive)
  90  * @param name_type netbios type of the name being looked up
  91  *
  92  * @return string consisted of uppercased name and appended
  93  *         type number
  94  */
  95
  96 static char* namecache_key(const char *name, int name_type)
  97 {
  98         char *keystr;
  99         asprintf(&keystr, NBTKEY_FMT, strupper_static(name), name_type);
 100
 101         return keystr;
 102 }
 103
 104
 105 /**
 106  * Store a name(s) in the name cache
 107  *
 108  * @param name netbios names array
 109  * @param name_type integer netbios name type
 110  * @param num_names number of names being stored
 111  * @param ip_list array of in_addr structures containing
 112  *        ip addresses being stored
 113  **/
 114
 115 BOOL namecache_store(const char *name, int name_type,
 116                      int num_names, struct ip_service *ip_list)
 117 {
 118         time_t expiry;
 119         char *key, *value_string;
 120         int i;
 121         BOOL ret;
 122
 123         /*
 124          * we use gecache call to avoid annoying debug messages about
 125          * initialised namecache again and again...
 126          */
 127         if (!gencache_init()) return False;
 128
 129         if ( DEBUGLEVEL >= 5 ) {
 130                 DEBUG(5, ("namecache_store: storing %d address%s for %s#%02x: ",
 131                         num_names, num_names == 1 ? "": "es", name, name_type));
 132
 133                 for (i = 0; i < num_names; i++)
 134                         DEBUGADD(5, ("%s:%d%s", inet_ntoa(ip_list[i].ip),
 135                                 ip_list[i].port, (i == (num_names - 1) ? "" : ",")));
 136
 137                 DEBUGADD(5, ("\n"));
 138         }
 139
 140         key = namecache_key(name, name_type);
 141         expiry = time(NULL) + lp_name_cache_timeout();
 142
 143         /*
 144          * Generate string representation of ip addresses list
 145          * First, store the number of ip addresses and then
 146          * place each single ip
 147          */
 148         if (!ipstr_list_make(&value_string, ip_list, num_names)) {
 149                 SAFE_FREE(key);
 150                 SAFE_FREE(value_string);
 151                 return False;
 152         }
 153
 154         /* set the entry */
 155         ret = gencache_set(key, value_string, expiry);
 156         SAFE_FREE(key);
 157         SAFE_FREE(value_string);
 158         return ret;
 159 }
 160
 161
 162 /**
 163  * Look up a name in the cache.
 164  *
 165  * @param name netbios name to look up for
 166  * @param name_type netbios name type of @param name
 167  * @param ip_list mallocated list of IP addresses if found in the cache,
 168  *        NULL otherwise
 169  * @param num_names number of entries found
 170  *
 171  * @return true upon successful fetch or
 172  *         false if name isn't found in the cache or has expired
 173  **/
 174
 175 BOOL namecache_fetch(const char *name, int name_type, struct ip_service **ip_list,
 176                      int *num_names)
 177 {
 178         char *key, *value;
 179         time_t timeout;
 180
 181         *num_names = 0;
 182
 183         /* exit now if null pointers were passed as they're required further */
 184         if (!ip_list || !num_names) return False;
 185
 186         if (!gencache_init())
 187                 return False;
 188
 189         /*
 190          * Use gencache interface - lookup the key
 191          */
 192         key = namecache_key(name, name_type);
 193
 194         if (!gencache_get(key, &value, &timeout)) {
 195                 DEBUG(5, ("no entry for %s#%02X found.\n", name, name_type));
 196                 gencache_del(key);
 197                 SAFE_FREE(key);
 198                 SAFE_FREE(value);
 199                 return False;
 200         } else {
 201                 DEBUG(5, ("name %s#%02X found.\n", name, name_type));
 202         }
 203
 204         /*
 205          * Split up the stored value into the list of IP adresses
 206          */
 207         *num_names = ipstr_list_parse(value, ip_list);
 208
 209         SAFE_FREE(key);
 210         SAFE_FREE(value);
 211
 212         return *num_names > 0;          /* true only if some ip has been fetched */
 213 }
 214
 215
 216 /**
 217  * Delete single namecache entry. Look at the
 218  * gencache_iterate definition.
 219  *
 220  **/
 221
 222 static void flush_netbios_name(const char* key, const char *value, time_t timeout, void* dptr)
 223 {
 224         gencache_del(key);
 225         DEBUG(5, ("Deleting entry %s\n", key));
 226 }
 227
 228
 229 /**
 230  * Flush all names from the name cache.
 231  * It's done by gencache_iterate()
 232  *
 233  * @return True upon successful deletion or
 234  *         False in case of an error
 235  **/
 236
 237 void namecache_flush(void)
 238 {
 239         if (!gencache_init())
 240                 return;
 241
 242         /*
 243          * iterate through each NBT cache's entry and flush it
 244          * by flush_netbios_name function
 245          */
 246         gencache_iterate(flush_netbios_name, NULL, "NBT/*");
 247         DEBUG(5, ("Namecache flushed\n"));
 248 }
 249
 250 /* Construct a name status record key. */
 251
 252 static char *namecache_status_record_key(const char *name, int name_type1,
 253                                 int name_type2, struct in_addr keyip)
 254 {
 255         char *keystr;
 256
 257         asprintf(&keystr, "NBT/%s#%02X.%02X.%s",
 258                         strupper_static(name), name_type1, name_type2, inet_ntoa(keyip));
 259         return keystr;
 260 }
 261
 262 /* Store a name status record. */
 263
 264 BOOL namecache_status_store(const char *keyname, int keyname_type,
 265                 int name_type, struct in_addr keyip,
 266                 const char *srvname)
 267 {
 268         char *key;
 269         time_t expiry;
 270         BOOL ret;
 271
 272         if (!gencache_init())
 273                 return False;
 274
 275         key = namecache_status_record_key(keyname, keyname_type, name_type, keyip);
 276         if (!key)
 277                 return False;
 278
 279         expiry = time(NULL) + lp_name_cache_timeout();
 280         ret = gencache_set(key, srvname, expiry);
 281
 282         if (ret)
 283                 DEBUG(5, ("namecache_status_store: entry %s -> %s\n", key, srvname ));
 284         else
 285                 DEBUG(5, ("namecache_status_store: entry %s store failed.\n", key ));
 286
 287         SAFE_FREE(key);
 288         return ret;
 289 }
 290
 291 /* Fetch a name status record. */
 292
 293 BOOL namecache_status_fetch(const char *keyname, int keyname_type,
 294                         int name_type, struct in_addr keyip, char *srvname_out)
 295 {
 296         char *key = NULL;
 297         char *value = NULL;
 298         time_t timeout;
 299
 300         if (!gencache_init())
 301                 return False;
 302
 303         key = namecache_status_record_key(keyname, keyname_type, name_type, keyip);
 304         if (!key)
 305                 return False;
 306
 307         if (!gencache_get(key, &value, &timeout)) {
 308                 DEBUG(5, ("namecache_status_fetch: no entry for %s found.\n", key));
 309                 gencache_del(key);
 310                 SAFE_FREE(key);
 311                 SAFE_FREE(value);
 312                 return False;
 313         } else {
 314                 DEBUG(5, ("namecache_status_fetch: key %s -> %s\n", key, value ));
 315         }
 316
 317         strlcpy(srvname_out, value, 16);
 318         SAFE_FREE(key);
 319         SAFE_FREE(value);
 320         return True;
 321 }