src/block/plugin_block_fs.c

   1 /*
   2      This file is part of GNUnet
   3      (C) 2010 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file block/plugin_block_fs.c
  23  * @brief blocks used for file-sharing
  24  * @author Christian Grothoff
  25  */
  26
  27 #include "platform.h"
  28 #include "gnunet_block_plugin.h"
  29 #include "block_fs.h"
  30 #include "gnunet_signatures.h"
  31
  32 #define DEBUG_FS_BLOCK GNUNET_NO
  33
  34 /**
  35  * Number of bits we set per entry in the bloomfilter.
  36  * Do not change!
  37  */
  38 #define BLOOMFILTER_K 16
  39
  40 /**
  41  * Function called to validate a reply or a request.  For
  42  * request evaluation, simply pass "NULL" for the reply_block.
  43  * Note that it is assumed that the reply has already been
  44  * matched to the key (and signatures checked) as it would
  45  * be done with the "get_key" function.
  46  *
  47  * @param cls closure
  48  * @param type block type
  49  * @param query original query (hash)
  50  * @param bf pointer to bloom filter associated with query; possibly updated (!)
  51  * @param bf_mutator mutation value for bf
  52  * @param xquery extrended query data (can be NULL, depending on type)
  53  * @param xquery_size number of bytes in xquery
  54  * @param reply_block response to validate
  55  * @param reply_block_size number of bytes in reply block
  56  * @return characterization of result
  57  */
  58 static enum GNUNET_BLOCK_EvaluationResult
  59 block_plugin_fs_evaluate (void *cls,
  60                           enum GNUNET_BLOCK_Type type,
  61                           const GNUNET_HashCode *query,
  62                           struct GNUNET_CONTAINER_BloomFilter **bf,
  63                           int32_t bf_mutator,
  64                           const void *xquery,
  65                           size_t xquery_size,
  66                           const void *reply_block,
  67                           size_t reply_block_size)
  68 {
  69   const struct SBlock *sb;
  70   GNUNET_HashCode chash;
  71   GNUNET_HashCode mhash;
  72   const GNUNET_HashCode *nsid;
  73   GNUNET_HashCode sh;
  74
  75   switch (type)
  76     {
  77     case GNUNET_BLOCK_TYPE_FS_DBLOCK:
  78     case GNUNET_BLOCK_TYPE_FS_IBLOCK:
  79       if (xquery_size != 0)
  80         {
  81           GNUNET_break_op (0);
  82           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  83         }
  84       if (reply_block == NULL)
  85         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  86       return GNUNET_BLOCK_EVALUATION_OK_LAST;
  87     case GNUNET_BLOCK_TYPE_FS_KBLOCK:
  88     case GNUNET_BLOCK_TYPE_FS_NBLOCK:
  89       if (xquery_size != 0)
  90         {
  91           GNUNET_break_op (0);
  92           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  93         }
  94       if (reply_block == NULL)
  95         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  96       GNUNET_CRYPTO_hash (reply_block,
  97                           reply_block_size,
  98                           &chash);
  99       GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
 100       if (NULL != *bf)
 101         {
 102           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 103                                                                &mhash))
 104             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 105         }
 106       else
 107         {
 108           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 109                                                    8,
 110                                                    BLOOMFILTER_K);
 111         }
 112       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 113       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 114     case GNUNET_BLOCK_TYPE_FS_SBLOCK:
 115       if (xquery_size != sizeof (GNUNET_HashCode))
 116         {
 117           GNUNET_break_op (0);
 118           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 119         }
 120       if (reply_block == NULL)
 121         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 122       nsid = xquery;
 123       if (reply_block_size < sizeof (struct SBlock))
 124         {
 125           GNUNET_break_op (0);
 126           return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 127         }
 128       sb = reply_block;
 129       GNUNET_CRYPTO_hash (&sb->subspace,
 130                           sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 131                           &sh);
 132       if (0 != memcmp (nsid,
 133                        &sh,
 134                        sizeof (GNUNET_HashCode)))
 135         {
 136           GNUNET_log_from (GNUNET_ERROR_TYPE_WARNING,
 137                            "block-fs",
 138                            _("Reply mismatched in terms of namespace.  Discarded.\n"));
 139           return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 140         }
 141       GNUNET_CRYPTO_hash (reply_block,
 142                           reply_block_size,
 143                           &chash);
 144       GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
 145       if (NULL != *bf)
 146         {
 147           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 148                                                                &mhash))
 149             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 150         }
 151       else
 152         {
 153           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 154                                                    8,
 155                                                    BLOOMFILTER_K);
 156         }
 157       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 158       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 159     default:
 160       return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
 161     }
 162 }
 163
 164
 165 /**
 166  * Function called to obtain the key for a block.
 167  *
 168  * @param cls closure
 169  * @param type block type
 170  * @param block block to get the key for
 171  * @param block_size number of bytes in block
 172  * @param key set to the key (query) for the given block
 173  * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
 174  *         (or if extracting a key from a block of this type does not work)
 175  */
 176 static int
 177 block_plugin_fs_get_key (void *cls,
 178                          enum GNUNET_BLOCK_Type type,
 179                          const void *block,
 180                          size_t block_size,
 181                          GNUNET_HashCode *key)
 182 {
 183   const struct KBlock *kb;
 184   const struct SBlock *sb;
 185   const struct NBlock *nb;
 186
 187   switch (type)
 188     {
 189     case GNUNET_BLOCK_TYPE_FS_DBLOCK:
 190     case GNUNET_BLOCK_TYPE_FS_IBLOCK:
 191       GNUNET_CRYPTO_hash (block, block_size, key);
 192       return GNUNET_OK;
 193     case GNUNET_BLOCK_TYPE_FS_KBLOCK:
 194       if (block_size < sizeof (struct KBlock))
 195         {
 196           GNUNET_break_op (0);
 197           return GNUNET_NO;
 198         }
 199       kb = block;
 200       if (block_size - sizeof (struct KBlock) !=
 201           ntohl (kb->purpose.size)
 202           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 203           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 204         {
 205           GNUNET_break_op (0);
 206           return GNUNET_NO;
 207         }
 208       if (GNUNET_OK !=
 209           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
 210                                     &kb->purpose,
 211                                     &kb->signature,
 212                                     &kb->keyspace))
 213         {
 214           GNUNET_break_op (0);
 215           return GNUNET_NO;
 216         }
 217       if (key != NULL)
 218         GNUNET_CRYPTO_hash (&kb->keyspace,
 219                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 220                             key);
 221       return GNUNET_OK;
 222     case GNUNET_BLOCK_TYPE_FS_SBLOCK:
 223       if (block_size < sizeof (struct SBlock))
 224         {
 225           GNUNET_break_op (0);
 226           return GNUNET_NO;
 227         }
 228       sb = block;
 229       if (block_size !=
 230           ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 231         {
 232           GNUNET_break_op (0);
 233           return GNUNET_NO;
 234         }
 235       if (GNUNET_OK !=
 236           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
 237                                     &sb->purpose,
 238                                     &sb->signature,
 239                                     &sb->subspace))
 240         {
 241           GNUNET_break_op (0);
 242           return GNUNET_NO;
 243         }
 244       if (key != NULL)
 245         *key = sb->identifier;
 246       return GNUNET_OK;
 247     case GNUNET_BLOCK_TYPE_FS_NBLOCK:
 248       if (block_size < sizeof (struct NBlock))
 249         {
 250           GNUNET_break_op (0);
 251           return GNUNET_NO;
 252         }
 253       nb = block;
 254       if (block_size - sizeof (struct NBlock) !=
 255           ntohl (nb->ns_purpose.size)
 256           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 257           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 258         {
 259           GNUNET_break_op (0);
 260           return GNUNET_NO;
 261         }
 262       if (block_size !=
 263           ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 264         {
 265           GNUNET_break_op (0);
 266           return GNUNET_NO;
 267         }
 268       if (GNUNET_OK !=
 269           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
 270                                     &nb->ksk_purpose,
 271                                     &nb->ksk_signature,
 272                                     &nb->keyspace))
 273         {
 274           GNUNET_break_op (0);
 275           return GNUNET_NO;
 276         }
 277       if (GNUNET_OK !=
 278           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
 279                                     &nb->ns_purpose,
 280                                     &nb->ns_signature,
 281                                     &nb->subspace))
 282         {
 283           GNUNET_break_op (0);
 284           return GNUNET_NO;
 285         }
 286       /* FIXME: we used to xor ID with NSID,
 287          why not here? */
 288       if (key != NULL)
 289         GNUNET_CRYPTO_hash (&nb->keyspace,
 290                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 291                             key);
 292       return GNUNET_OK;
 293     default:
 294       return GNUNET_SYSERR;
 295     }
 296 }
 297
 298
 299 /**
 300  * Entry point for the plugin.
 301  */
 302 void *
 303 libgnunet_plugin_block_fs_init (void *cls)
 304 {
 305   static enum GNUNET_BLOCK_Type types[] =
 306     {
 307       GNUNET_BLOCK_TYPE_FS_DBLOCK,
 308       GNUNET_BLOCK_TYPE_FS_IBLOCK,
 309       GNUNET_BLOCK_TYPE_FS_KBLOCK,
 310       GNUNET_BLOCK_TYPE_FS_SBLOCK,
 311       GNUNET_BLOCK_TYPE_FS_NBLOCK,
 312       GNUNET_BLOCK_TYPE_ANY /* end of list */
 313     };
 314   struct GNUNET_BLOCK_PluginFunctions *api;
 315
 316   api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
 317   api->evaluate = &block_plugin_fs_evaluate;
 318   api->get_key = &block_plugin_fs_get_key;
 319   api->types = types;
 320   return api;
 321 }
 322
 323
 324 /**
 325  * Exit point from the plugin.
 326  */
 327 void *
 328 libgnunet_plugin_block_fs_done (void *cls)
 329 {
 330   struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
 331
 332   GNUNET_free (api);
 333   return NULL;
 334 }
 335
 336 /* end of plugin_block_fs.c */