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  * Mingle hash with the mingle_number to produce different bits.
  42  */
  43 static void
  44 mingle_hash (const GNUNET_HashCode * in,
  45              int32_t mingle_number,
  46              GNUNET_HashCode * hc)
  47 {
  48   GNUNET_HashCode m;
  49
  50   GNUNET_CRYPTO_hash (&mingle_number,
  51                       sizeof (int32_t),
  52                       &m);
  53   GNUNET_CRYPTO_hash_xor (&m, in, hc);
  54 }
  55
  56
  57 /**
  58  * Function called to validate a reply or a request.  For
  59  * request evaluation, simply pass "NULL" for the reply_block.
  60  * Note that it is assumed that the reply has already been
  61  * matched to the key (and signatures checked) as it would
  62  * be done with the "get_key" function.
  63  *
  64  * @param cls closure
  65  * @param type block type
  66  * @param query original query (hash)
  67  * @param bf pointer to bloom filter associated with query; possibly updated (!)
  68  * @param bf_mutator mutation value for bf
  69  * @param xquery extrended query data (can be NULL, depending on type)
  70  * @param xquery_size number of bytes in xquery
  71  * @param reply_block response to validate
  72  * @param reply_block_size number of bytes in reply block
  73  * @return characterization of result
  74  */
  75 static enum GNUNET_BLOCK_EvaluationResult
  76 block_plugin_fs_evaluate (void *cls,
  77                           enum GNUNET_BLOCK_Type type,
  78                           const GNUNET_HashCode *query,
  79                           struct GNUNET_CONTAINER_BloomFilter **bf,
  80                           int32_t bf_mutator,
  81                           const void *xquery,
  82                           size_t xquery_size,
  83                           const void *reply_block,
  84                           size_t reply_block_size)
  85 {
  86   const struct SBlock *sb;
  87   GNUNET_HashCode chash;
  88   GNUNET_HashCode mhash;
  89   const GNUNET_HashCode *nsid;
  90   GNUNET_HashCode sh;
  91
  92   switch (type)
  93     {
  94     case GNUNET_BLOCK_TYPE_DBLOCK:
  95     case GNUNET_BLOCK_TYPE_IBLOCK:
  96       if (xquery_size != 0)
  97         {
  98           GNUNET_break_op (0);
  99           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 100         }
 101       if (reply_block == NULL)
 102         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 103       return GNUNET_BLOCK_EVALUATION_OK_LAST;
 104     case GNUNET_BLOCK_TYPE_KBLOCK:
 105     case GNUNET_BLOCK_TYPE_NBLOCK:
 106       if (xquery_size != 0)
 107         {
 108           GNUNET_break_op (0);
 109           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 110         }
 111       if (reply_block == NULL)
 112         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 113       GNUNET_CRYPTO_hash (reply_block,
 114                           reply_block_size,
 115                           &chash);
 116       mingle_hash (&chash, bf_mutator, &mhash);
 117       if (NULL != *bf)
 118         {
 119           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 120                                                                &mhash))
 121             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 122         }
 123       else
 124         {
 125           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 126                                                    8,
 127                                                    BLOOMFILTER_K);
 128         }
 129       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 130       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 131     case GNUNET_BLOCK_TYPE_SBLOCK:
 132       if (xquery_size != sizeof (GNUNET_HashCode))
 133         {
 134           GNUNET_break_op (0);
 135           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 136         }
 137       if (reply_block == NULL)
 138         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 139       nsid = xquery;
 140       if (reply_block_size < sizeof (struct NBlock))
 141         return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 142       sb = reply_block;
 143       GNUNET_CRYPTO_hash (&sb->subspace,
 144                           sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 145                           &sh);
 146       if (0 != memcmp (nsid,
 147                        &sh,
 148                        sizeof (GNUNET_HashCode)))
 149         {
 150           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 151                       _("Reply mismatched in terms of namespace.  Discarded.\n"));
 152           return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 153         }
 154       GNUNET_CRYPTO_hash (reply_block,
 155                           reply_block_size,
 156                           &chash);
 157       mingle_hash (&chash, bf_mutator, &mhash);
 158       if (NULL != *bf)
 159         {
 160           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 161                                                                &mhash))
 162             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 163         }
 164       else
 165         {
 166           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 167                                                    8,
 168                                                    BLOOMFILTER_K);
 169         }
 170       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 171       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 172     default:
 173       return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
 174     }
 175 }
 176
 177
 178 /**
 179  * Function called to obtain the key for a block.
 180  *
 181  * @param cls closure
 182  * @param type block type
 183  * @param block block to get the key for
 184  * @param block_size number of bytes in block
 185  * @param key set to the key (query) for the given block
 186  * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
 187  *         (or if extracting a key from a block of this type does not work)
 188  */
 189 static int
 190 block_plugin_fs_get_key (void *cls,
 191                          enum GNUNET_BLOCK_Type type,
 192                          const void *block,
 193                          size_t block_size,
 194                          GNUNET_HashCode *key)
 195 {
 196   const struct KBlock *kb;
 197   const struct SBlock *sb;
 198   const struct NBlock *nb;
 199
 200   switch (type)
 201     {
 202     case GNUNET_BLOCK_TYPE_DBLOCK:
 203     case GNUNET_BLOCK_TYPE_IBLOCK:
 204       GNUNET_CRYPTO_hash (block, block_size, key);
 205       return GNUNET_OK;
 206     case GNUNET_BLOCK_TYPE_KBLOCK:
 207       if (block_size < sizeof (struct KBlock))
 208         {
 209           GNUNET_break_op (0);
 210           return GNUNET_SYSERR;
 211         }
 212       kb = block;
 213       if (block_size - sizeof (struct KBlock) !=
 214           ntohl (kb->purpose.size)
 215           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 216           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 217         {
 218           GNUNET_break_op (0);
 219           return GNUNET_SYSERR;
 220         }
 221       if (GNUNET_OK !=
 222           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
 223                                     &kb->purpose,
 224                                     &kb->signature,
 225                                     &kb->keyspace))
 226         {
 227           GNUNET_break_op (0);
 228           return GNUNET_SYSERR;
 229         }
 230       if (key != NULL)
 231         GNUNET_CRYPTO_hash (&kb->keyspace,
 232                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 233                             key);
 234       return GNUNET_OK;
 235     case GNUNET_BLOCK_TYPE_SBLOCK:
 236       if (block_size < sizeof (struct SBlock))
 237         {
 238           GNUNET_break_op (0);
 239           return GNUNET_SYSERR;
 240         }
 241       sb = block;
 242       if (block_size !=
 243           ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 244         {
 245           GNUNET_break_op (0);
 246           return GNUNET_SYSERR;
 247         }
 248       if (GNUNET_OK !=
 249           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
 250                                     &sb->purpose,
 251                                     &sb->signature,
 252                                     &sb->subspace))
 253         {
 254           GNUNET_break_op (0);
 255           return GNUNET_SYSERR;
 256         }
 257       if (key != NULL)
 258         *key = sb->identifier;
 259       return GNUNET_OK;
 260     case GNUNET_BLOCK_TYPE_NBLOCK:
 261       if (block_size < sizeof (struct NBlock))
 262         {
 263           GNUNET_break_op (0);
 264           return GNUNET_SYSERR;
 265         }
 266       nb = block;
 267       if (block_size - sizeof (struct NBlock) !=
 268           ntohl (nb->ns_purpose.size)
 269           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 270           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 271         {
 272           GNUNET_break_op (0);
 273           return GNUNET_SYSERR;
 274         }
 275       if (block_size !=
 276           ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 277         {
 278           GNUNET_break_op (0);
 279           return GNUNET_SYSERR;
 280         }
 281       if (GNUNET_OK !=
 282           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
 283                                     &nb->ksk_purpose,
 284                                     &nb->ksk_signature,
 285                                     &nb->keyspace))
 286         {
 287           GNUNET_break_op (0);
 288           return GNUNET_SYSERR;
 289         }
 290       if (GNUNET_OK !=
 291           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
 292                                     &nb->ns_purpose,
 293                                     &nb->ns_signature,
 294                                     &nb->subspace))
 295         {
 296           GNUNET_break_op (0);
 297           return GNUNET_SYSERR;
 298         }
 299       /* FIXME: we used to xor ID with NSID,
 300          why not here? */
 301       if (key != NULL)
 302         GNUNET_CRYPTO_hash (&nb->keyspace,
 303                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 304                             key);
 305       return GNUNET_OK;
 306     default:
 307       return GNUNET_SYSERR;
 308     }
 309 }
 310
 311
 312 /**
 313  * Entry point for the plugin.
 314  */
 315 void *
 316 libgnunet_plugin_block_fs_init (void *cls)
 317 {
 318   static enum GNUNET_BLOCK_Type types[] =
 319     {
 320       GNUNET_BLOCK_TYPE_DBLOCK,
 321       GNUNET_BLOCK_TYPE_IBLOCK,
 322       GNUNET_BLOCK_TYPE_KBLOCK,
 323       GNUNET_BLOCK_TYPE_SBLOCK,
 324       GNUNET_BLOCK_TYPE_NBLOCK,
 325       GNUNET_BLOCK_TYPE_ANY /* end of list */
 326     };
 327   struct GNUNET_BLOCK_PluginFunctions *api;
 328
 329   api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
 330   api->evaluate = &block_plugin_fs_evaluate;
 331   api->get_key = &block_plugin_fs_get_key;
 332   api->types = types;
 333   return api;
 334 }
 335
 336
 337 /**
 338  * Exit point from the plugin.
 339  */
 340 void *
 341 libgnunet_plugin_block_fs_done (void *cls)
 342 {
 343   struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
 344
 345   GNUNET_free (api);
 346   return NULL;
 347 }
 348
 349 /* end of plugin_block_fs.c */