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 "plugin_block.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_DBLOCK:
  78     case GNUNET_BLOCK_TYPE_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_KBLOCK:
  88     case GNUNET_BLOCK_TYPE_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_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 NBlock))
 124         return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 125       sb = reply_block;
 126       GNUNET_CRYPTO_hash (&sb->subspace,
 127                           sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 128                           &sh);
 129       if (0 != memcmp (nsid,
 130                        &sh,
 131                        sizeof (GNUNET_HashCode)))
 132         {
 133           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 134                       _("Reply mismatched in terms of namespace.  Discarded.\n"));
 135           return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 136         }
 137       GNUNET_CRYPTO_hash (reply_block,
 138                           reply_block_size,
 139                           &chash);
 140       GNUNET_BLOCK_mingle_hash (&chash, bf_mutator, &mhash);
 141       if (NULL != *bf)
 142         {
 143           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 144                                                                &mhash))
 145             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 146         }
 147       else
 148         {
 149           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 150                                                    8,
 151                                                    BLOOMFILTER_K);
 152         }
 153       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 154       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 155     default:
 156       return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
 157     }
 158 }
 159
 160
 161 /**
 162  * Function called to obtain the key for a block.
 163  *
 164  * @param cls closure
 165  * @param type block type
 166  * @param block block to get the key for
 167  * @param block_size number of bytes in block
 168  * @param key set to the key (query) for the given block
 169  * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
 170  *         (or if extracting a key from a block of this type does not work)
 171  */
 172 static int
 173 block_plugin_fs_get_key (void *cls,
 174                          enum GNUNET_BLOCK_Type type,
 175                          const void *block,
 176                          size_t block_size,
 177                          GNUNET_HashCode *key)
 178 {
 179   const struct KBlock *kb;
 180   const struct SBlock *sb;
 181   const struct NBlock *nb;
 182
 183   switch (type)
 184     {
 185     case GNUNET_BLOCK_TYPE_DBLOCK:
 186     case GNUNET_BLOCK_TYPE_IBLOCK:
 187       GNUNET_CRYPTO_hash (block, block_size, key);
 188       return GNUNET_OK;
 189     case GNUNET_BLOCK_TYPE_KBLOCK:
 190       if (block_size < sizeof (struct KBlock))
 191         {
 192           GNUNET_break_op (0);
 193           return GNUNET_SYSERR;
 194         }
 195       kb = block;
 196       if (block_size - sizeof (struct KBlock) !=
 197           ntohl (kb->purpose.size)
 198           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 199           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 200         {
 201           GNUNET_break_op (0);
 202           return GNUNET_SYSERR;
 203         }
 204       if (GNUNET_OK !=
 205           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
 206                                     &kb->purpose,
 207                                     &kb->signature,
 208                                     &kb->keyspace))
 209         {
 210           GNUNET_break_op (0);
 211           return GNUNET_SYSERR;
 212         }
 213       if (key != NULL)
 214         GNUNET_CRYPTO_hash (&kb->keyspace,
 215                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 216                             key);
 217       return GNUNET_OK;
 218     case GNUNET_BLOCK_TYPE_SBLOCK:
 219       if (block_size < sizeof (struct SBlock))
 220         {
 221           GNUNET_break_op (0);
 222           return GNUNET_SYSERR;
 223         }
 224       sb = block;
 225       if (block_size !=
 226           ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 227         {
 228           GNUNET_break_op (0);
 229           return GNUNET_SYSERR;
 230         }
 231       if (GNUNET_OK !=
 232           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
 233                                     &sb->purpose,
 234                                     &sb->signature,
 235                                     &sb->subspace))
 236         {
 237           GNUNET_break_op (0);
 238           return GNUNET_SYSERR;
 239         }
 240       if (key != NULL)
 241         *key = sb->identifier;
 242       return GNUNET_OK;
 243     case GNUNET_BLOCK_TYPE_NBLOCK:
 244       if (block_size < sizeof (struct NBlock))
 245         {
 246           GNUNET_break_op (0);
 247           return GNUNET_SYSERR;
 248         }
 249       nb = block;
 250       if (block_size - sizeof (struct NBlock) !=
 251           ntohl (nb->ns_purpose.size)
 252           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 253           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 254         {
 255           GNUNET_break_op (0);
 256           return GNUNET_SYSERR;
 257         }
 258       if (block_size !=
 259           ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 260         {
 261           GNUNET_break_op (0);
 262           return GNUNET_SYSERR;
 263         }
 264       if (GNUNET_OK !=
 265           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
 266                                     &nb->ksk_purpose,
 267                                     &nb->ksk_signature,
 268                                     &nb->keyspace))
 269         {
 270           GNUNET_break_op (0);
 271           return GNUNET_SYSERR;
 272         }
 273       if (GNUNET_OK !=
 274           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
 275                                     &nb->ns_purpose,
 276                                     &nb->ns_signature,
 277                                     &nb->subspace))
 278         {
 279           GNUNET_break_op (0);
 280           return GNUNET_SYSERR;
 281         }
 282       /* FIXME: we used to xor ID with NSID,
 283          why not here? */
 284       if (key != NULL)
 285         GNUNET_CRYPTO_hash (&nb->keyspace,
 286                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 287                             key);
 288       return GNUNET_OK;
 289     default:
 290       return GNUNET_SYSERR;
 291     }
 292 }
 293
 294
 295 /**
 296  * Entry point for the plugin.
 297  */
 298 void *
 299 libgnunet_plugin_block_fs_init (void *cls)
 300 {
 301   static enum GNUNET_BLOCK_Type types[] =
 302     {
 303       GNUNET_BLOCK_TYPE_DBLOCK,
 304       GNUNET_BLOCK_TYPE_IBLOCK,
 305       GNUNET_BLOCK_TYPE_KBLOCK,
 306       GNUNET_BLOCK_TYPE_SBLOCK,
 307       GNUNET_BLOCK_TYPE_NBLOCK,
 308       GNUNET_BLOCK_TYPE_ANY /* end of list */
 309     };
 310   struct GNUNET_BLOCK_PluginFunctions *api;
 311
 312   api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
 313   api->evaluate = &block_plugin_fs_evaluate;
 314   api->get_key = &block_plugin_fs_get_key;
 315   api->types = types;
 316   return api;
 317 }
 318
 319
 320 /**
 321  * Exit point from the plugin.
 322  */
 323 void *
 324 libgnunet_plugin_block_fs_done (void *cls)
 325 {
 326   struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
 327
 328   GNUNET_free (api);
 329   return NULL;
 330 }
 331
 332 /* end of plugin_block_fs.c */