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  * Generates a key for netbios name lookups on basis of
  30  * netbios name and type.
  31  * The caller must free returned key string when finished.
  32  *
  33  * @param name netbios name string (case insensitive)
  34  * @param name_type netbios type of the name being looked up
  35  *
  36  * @return string consisted of uppercased name and appended
  37  *         type number
  38  */
  39
  40 static char *namecache_key(const char *name,
  41                                 int name_type)
  42 {
  43         char *keystr = NULL;
  44         asprintf_strupper_m(&keystr, NBTKEY_FMT, name, name_type);
  45
  46         return keystr;
  47 }
  48
  49 /**
  50  * Store a name(s) in the name cache
  51  *
  52  * @param name netbios names array
  53  * @param name_type integer netbios name type
  54  * @param num_names number of names being stored
  55  * @param ip_list array of in_addr structures containing
  56  *        ip addresses being stored
  57  **/
  58
  59 bool namecache_store(const char *name,
  60                         int name_type,
  61                         int num_names,
  62                         struct ip_service *ip_list)
  63 {
  64         time_t expiry;
  65         char *key, *value_string;
  66         int i;
  67         bool ret;
  68
  69         if (name_type > 255) {
  70                 return False; /* Don't store non-real name types. */
  71         }
  72
  73         if ( DEBUGLEVEL >= 5 ) {
  74                 TALLOC_CTX *ctx = talloc_stackframe();
  75                 char *addr = NULL;
  76
  77                 DEBUG(5, ("namecache_store: storing %d address%s for %s#%02x: ",
  78                         num_names, num_names == 1 ? "": "es", name, name_type));
  79
  80                 for (i = 0; i < num_names; i++) {
  81                         addr = print_canonical_sockaddr(ctx,
  82                                                         &ip_list[i].ss);
  83                         if (!addr) {
  84                                 continue;
  85                         }
  86                         DEBUGADD(5, ("%s%s", addr,
  87                                 (i == (num_names - 1) ? "" : ",")));
  88
  89                 }
  90                 DEBUGADD(5, ("\n"));
  91                 TALLOC_FREE(ctx);
  92         }
  93
  94         key = namecache_key(name, name_type);
  95         if (!key) {
  96                 return False;
  97         }
  98
  99         expiry = time(NULL) + lp_name_cache_timeout();
 100
 101         /*
 102          * Generate string representation of ip addresses list
 103          * First, store the number of ip addresses and then
 104          * place each single ip
 105          */
 106         if (!ipstr_list_make(&value_string, ip_list, num_names)) {
 107                 SAFE_FREE(key);
 108                 SAFE_FREE(value_string);
 109                 return false;
 110         }
 111
 112         /* set the entry */
 113         ret = gencache_set(key, value_string, expiry);
 114         SAFE_FREE(key);
 115         SAFE_FREE(value_string);
 116         return ret;
 117 }
 118
 119 /**
 120  * Look up a name in the cache.
 121  *
 122  * @param name netbios name to look up for
 123  * @param name_type netbios name type of @param name
 124  * @param ip_list mallocated list of IP addresses if found in the cache,
 125  *        NULL otherwise
 126  * @param num_names number of entries found
 127  *
 128  * @return true upon successful fetch or
 129  *         false if name isn't found in the cache or has expired
 130  **/
 131
 132 bool namecache_fetch(const char *name,
 133                         int name_type,
 134                         struct ip_service **ip_list,
 135                         int *num_names)
 136 {
 137         char *key, *value;
 138         time_t timeout;
 139
 140         /* exit now if null pointers were passed as they're required further */
 141         if (!ip_list || !num_names) {
 142                 return False;
 143         }
 144
 145         if (name_type > 255) {
 146                 return False; /* Don't fetch non-real name types. */
 147         }
 148
 149         *num_names = 0;
 150
 151         /*
 152          * Use gencache interface - lookup the key
 153          */
 154         key = namecache_key(name, name_type);
 155         if (!key) {
 156                 return False;
 157         }
 158
 159         if (!gencache_get(key, talloc_tos(), &value, &timeout)) {
 160                 DEBUG(5, ("no entry for %s#%02X found.\n", name, name_type));
 161                 SAFE_FREE(key);
 162                 return False;
 163         }
 164
 165         DEBUG(5, ("name %s#%02X found.\n", name, name_type));
 166
 167         /*
 168          * Split up the stored value into the list of IP adresses
 169          */
 170         *num_names = ipstr_list_parse(value, ip_list);
 171
 172         SAFE_FREE(key);
 173         TALLOC_FREE(value);
 174
 175         return *num_names > 0; /* true only if some ip has been fetched */
 176 }
 177
 178 /**
 179  * Remove a namecache entry. Needed for site support.
 180  *
 181  **/
 182
 183 bool namecache_delete(const char *name, int name_type)
 184 {
 185         bool ret;
 186         char *key;
 187
 188         if (name_type > 255) {
 189                 return False; /* Don't fetch non-real name types. */
 190         }
 191
 192         key = namecache_key(name, name_type);
 193         if (!key) {
 194                 return False;
 195         }
 196         ret = gencache_del(key);
 197         SAFE_FREE(key);
 198         return ret;
 199 }
 200
 201 /**
 202  * Delete single namecache entry. Look at the
 203  * gencache_iterate definition.
 204  *
 205  **/
 206
 207 static void flush_netbios_name(const char *key,
 208                         const char *value,
 209                         time_t timeout,
 210                         void *dptr)
 211 {
 212         gencache_del(key);
 213         DEBUG(5, ("Deleting entry %s\n", key));
 214 }
 215
 216 /**
 217  * Flush all names from the name cache.
 218  * It's done by gencache_iterate()
 219  *
 220  * @return true upon successful deletion or
 221  *         false in case of an error
 222  **/
 223
 224 void namecache_flush(void)
 225 {
 226         /*
 227          * iterate through each NBT cache's entry and flush it
 228          * by flush_netbios_name function
 229          */
 230         gencache_iterate(flush_netbios_name, NULL, "NBT/*");
 231         DEBUG(5, ("Namecache flushed\n"));
 232 }
 233
 234 /* Construct a name status record key. */
 235
 236 static char *namecache_status_record_key(const char *name,
 237                                 int name_type1,
 238                                 int name_type2,
 239                                 const struct sockaddr_storage *keyip)
 240 {
 241         char addr[INET6_ADDRSTRLEN];
 242         char *keystr = NULL;
 243
 244         print_sockaddr(addr, sizeof(addr), keyip);
 245         asprintf_strupper_m(&keystr, "NBT/%s#%02X.%02X.%s", name,
 246                             name_type1, name_type2, addr);
 247         return keystr;
 248 }
 249
 250 /* Store a name status record. */
 251
 252 bool namecache_status_store(const char *keyname, int keyname_type,
 253                 int name_type, const struct sockaddr_storage *keyip,
 254                 const char *srvname)
 255 {
 256         char *key;
 257         time_t expiry;
 258         bool ret;
 259
 260         key = namecache_status_record_key(keyname, keyname_type,
 261                         name_type, keyip);
 262         if (!key)
 263                 return False;
 264
 265         expiry = time(NULL) + lp_name_cache_timeout();
 266         ret = gencache_set(key, srvname, expiry);
 267
 268         if (ret) {
 269                 DEBUG(5, ("namecache_status_store: entry %s -> %s\n",
 270                                         key, srvname ));
 271         } else {
 272                 DEBUG(5, ("namecache_status_store: entry %s store failed.\n",
 273                                         key ));
 274         }
 275
 276         SAFE_FREE(key);
 277         return ret;
 278 }
 279
 280 /* Fetch a name status record. */
 281
 282 bool namecache_status_fetch(const char *keyname,
 283                                 int keyname_type,
 284                                 int name_type,
 285                                 const struct sockaddr_storage *keyip,
 286                                 char *srvname_out)
 287 {
 288         char *key = NULL;
 289         char *value = NULL;
 290         time_t timeout;
 291
 292         key = namecache_status_record_key(keyname, keyname_type,
 293                         name_type, keyip);
 294         if (!key)
 295                 return False;
 296
 297         if (!gencache_get(key, talloc_tos(), &value, &timeout)) {
 298                 DEBUG(5, ("namecache_status_fetch: no entry for %s found.\n",
 299                                         key));
 300                 SAFE_FREE(key);
 301                 return False;
 302         } else {
 303                 DEBUG(5, ("namecache_status_fetch: key %s -> %s\n",
 304                                         key, value ));
 305         }
 306
 307         strlcpy(srvname_out, value, 16);
 308         SAFE_FREE(key);
 309         TALLOC_FREE(value);
 310         return True;
 311 }