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 "gnunet_signatures.h"
  30
  31 #define DEBUG_FS_BLOCK GNUNET_NO
  32
  33 /**
  34  * Number of bits we set per entry in the bloomfilter.
  35  * Do not change!
  36  */
  37 #define BLOOMFILTER_K 16
  38
  39 /**
  40  * Mingle hash with the mingle_number to produce different bits.
  41  */
  42 static void
  43 mingle_hash (const GNUNET_HashCode * in,
  44              int32_t mingle_number,
  45              GNUNET_HashCode * hc)
  46 {
  47   GNUNET_HashCode m;
  48
  49   GNUNET_CRYPTO_hash (&mingle_number,
  50                       sizeof (int32_t),
  51                       &m);
  52   GNUNET_CRYPTO_hash_xor (&m, in, hc);
  53 }
  54
  55
  56 /**
  57  * Function called to validate a reply or a request.  For
  58  * request evaluation, simply pass "NULL" for the reply_block.
  59  * Note that it is assumed that the reply has already been
  60  * matched to the key (and signatures checked) as it would
  61  * be done with the "get_key" function.
  62  *
  63  * @param cls closure
  64  * @param type block type
  65  * @param query original query (hash)
  66  * @param bf pointer to bloom filter associated with query; possibly updated (!)
  67  * @param bf_mutator mutation value for bf
  68  * @param xquery extrended query data (can be NULL, depending on type)
  69  * @param xquery_size number of bytes in xquery
  70  * @param reply_block response to validate
  71  * @param reply_block_size number of bytes in reply block
  72  * @return characterization of result
  73  */
  74 static enum GNUNET_BLOCK_EvaluationResult
  75 block_plugin_fs_evaluate (void *cls,
  76                           enum GNUNET_BLOCK_Type type,
  77                           const GNUNET_HashCode *query,
  78                           struct GNUNET_CONTAINER_BloomFilter **bf,
  79                           int32_t bf_mutator,
  80                           const void *xquery,
  81                           size_t xquery_size,
  82                           const void *reply_block,
  83                           size_t reply_block_size)
  84 {
  85   const struct SBlock *sb;
  86   GNUNET_HashCode chash;
  87   GNUNET_HashCode mhash;
  88   const GNUNET_HashCode *nsid;
  89   GNUNET_HashCode sh;
  90
  91   switch (type)
  92     {
  93     case GNUNET_BLOCK_TYPE_DBLOCK:
  94     case GNUNET_BLOCK_TYPE_IBLOCK:
  95       if (xquery_size != 0)
  96         {
  97           GNUNET_break_op (0);
  98           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  99         }
 100       return GNUNET_BLOCK_EVALUATION_OK_LAST;
 101     case GNUNET_BLOCK_TYPE_KBLOCK:
 102     case GNUNET_BLOCK_TYPE_NBLOCK:
 103       if (xquery_size != 0)
 104         {
 105           GNUNET_break_op (0);
 106           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 107         }
 108       if (reply_block == NULL)
 109         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 110       GNUNET_CRYPTO_hash (reply_block,
 111                           reply_block_size,
 112                           &chash);
 113       mingle_hash (&chash, bf_mutator, &mhash);
 114       if (NULL != *bf)
 115         {
 116           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 117                                                                &mhash))
 118             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 119         }
 120       else
 121         {
 122           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 123                                                    8,
 124                                                    BLOOMFILTER_K);
 125         }
 126       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 127       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 128     case GNUNET_BLOCK_TYPE_SBLOCK:
 129       if (xquery_size != sizeof (GNUNET_HashCode))
 130         {
 131           GNUNET_break_op (0);
 132           return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
 133         }
 134       if (reply_block == NULL)
 135         return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
 136       nsid = xquery;
 137       if (reply_block_size < sizeof (struct NBlock))
 138         return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 139       sb = reply_block;
 140       GNUNET_CRYPTO_hash (&sb->subspace,
 141                           sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 142                           &sh);
 143       if (0 != memcmp (nsid,
 144                        &sh,
 145                        sizeof (GNUNET_HashCode)))
 146         {
 147           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
 148                       _("Reply mismatched in terms of namespace.  Discarded.\n"));
 149           return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
 150         }
 151       GNUNET_CRYPTO_hash (reply_block,
 152                           reply_block_size,
 153                           &chash);
 154       mingle_hash (&chash, bf_mutator, &mhash);
 155       if (NULL != *bf)
 156         {
 157           if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
 158                                                                &mhash))
 159             return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
 160         }
 161       else
 162         {
 163           *bf = GNUNET_CONTAINER_bloomfilter_init (NULL,
 164                                                    8,
 165                                                    BLOOMFILTER_K);
 166         }
 167       GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
 168       return GNUNET_BLOCK_EVALUATION_OK_MORE;
 169     default:
 170       return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
 171     }
 172 }
 173
 174
 175 /**
 176  * Function called to obtain the key for a block.
 177  *
 178  * @param cls closure
 179  * @param type block type
 180  * @param block block to get the key for
 181  * @param block_size number of bytes in block
 182  * @param key set to the key (query) for the given block
 183  * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
 184  *         (or if extracting a key from a block of this type does not work)
 185  */
 186 static int
 187 block_plugin_fs_get_key (void *cls,
 188                          enum GNUNET_BLOCK_Type type,
 189                          const void *block,
 190                          size_t block_size,
 191                          GNUNET_HashCode *key)
 192 {
 193   const struct KBlock *kb;
 194   const struct SBlock *sb;
 195   const struct NBlock *nb;
 196
 197   switch (type)
 198     {
 199     case GNUNET_BLOCK_TYPE_DBLOCK:
 200     case GNUNET_BLOCK_TYPE_IBLOCK:
 201       GNUNET_CRYPTO_hash (block, block_size, key);
 202       return GNUNET_OK;
 203     case GNUNET_BLOCK_TYPE_KBLOCK:
 204       if (block_size < sizeof (struct KBlock))
 205         {
 206           GNUNET_break_op (0);
 207           return GNUNET_SYSERR;
 208         }
 209       kb = block;
 210       if (block_size - sizeof (struct KBlock) !=
 211           ntohl (kb->purpose.size)
 212           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 213           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 214         {
 215           GNUNET_break_op (0);
 216           return GNUNET_SYSERR;
 217         }
 218       if (GNUNET_OK !=
 219           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
 220                                     &kb->purpose,
 221                                     &kb->signature,
 222                                     &kb->keyspace))
 223         {
 224           GNUNET_break_op (0);
 225           return GNUNET_SYSERR;
 226         }
 227       if (key != NULL)
 228         GNUNET_CRYPTO_hash (&kb->keyspace,
 229                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 230                             key);
 231       return GNUNET_OK;
 232     case GNUNET_BLOCK_TYPE_SBLOCK:
 233       if (block_size < sizeof (struct SBlock))
 234         {
 235           GNUNET_break_op (0);
 236           return GNUNET_SYSERR;
 237         }
 238       sb = block;
 239       if (block_size !=
 240           ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 241         {
 242           GNUNET_break_op (0);
 243           return GNUNET_SYSERR;
 244         }
 245       if (GNUNET_OK !=
 246           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
 247                                     &sb->purpose,
 248                                     &sb->signature,
 249                                     &sb->subspace))
 250         {
 251           GNUNET_break_op (0);
 252           return GNUNET_SYSERR;
 253         }
 254       if (key != NULL)
 255         *key = sb->identifier;
 256       return GNUNET_OK;
 257     case GNUNET_BLOCK_TYPE_NBLOCK:
 258       if (block_size < sizeof (struct NBlock))
 259         {
 260           GNUNET_break_op (0);
 261           return GNUNET_SYSERR;
 262         }
 263       nb = block;
 264       if (block_size - sizeof (struct NBlock) !=
 265           ntohl (nb->ns_purpose.size)
 266           - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose)
 267           - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) )
 268         {
 269           GNUNET_break_op (0);
 270           return GNUNET_SYSERR;
 271         }
 272       if (block_size !=
 273           ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
 274         {
 275           GNUNET_break_op (0);
 276           return GNUNET_SYSERR;
 277         }
 278       if (GNUNET_OK !=
 279           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
 280                                     &nb->ksk_purpose,
 281                                     &nb->ksk_signature,
 282                                     &nb->keyspace))
 283         {
 284           GNUNET_break_op (0);
 285           return GNUNET_SYSERR;
 286         }
 287       if (GNUNET_OK !=
 288           GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
 289                                     &nb->ns_purpose,
 290                                     &nb->ns_signature,
 291                                     &nb->subspace))
 292         {
 293           GNUNET_break_op (0);
 294           return GNUNET_SYSERR;
 295         }
 296       /* FIXME: we used to xor ID with NSID,
 297          why not here? */
 298       if (key != NULL)
 299         GNUNET_CRYPTO_hash (&nb->keyspace,
 300                             sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 301                             key);
 302       return GNUNET_OK;
 303     default:
 304       return GNUNET_SYSERR;
 305     }
 306 }
 307
 308
 309 /**
 310  * Entry point for the plugin.
 311  */
 312 void *
 313 gnunet_plugin_block_fs_init (void *cls)
 314 {
 315   static enum GNUNET_BLOCK_Type types[] =
 316     {
 317       GNUNET_BLOCK_TYPE_DBLOCK,
 318       GNUNET_BLOCK_TYPE_IBLOCK,
 319       GNUNET_BLOCK_TYPE_KBLOCK,
 320       GNUNET_BLOCK_TYPE_SBLOCK,
 321       GNUNET_BLOCK_TYPE_NBLOCK,
 322       GNUNET_BLOCK_TYPE_ANY /* end of list */
 323     };
 324   struct GNUNET_BLOCK_PluginFunctions *api;
 325
 326   api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
 327   api->evaluate = &block_plugin_fs_evaluate;
 328   api->get_key = &block_plugin_fs_get_key;
 329   api->types = types;
 330   return api;
 331 }
 332
 333
 334 /**
 335  * Exit point from the plugin.
 336  */
 337 void *
 338 gnunet_plugin_block_fs_done (void *cls)
 339 {
 340   struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
 341
 342   GNUNET_free (api);
 343   return NULL;
 344 }
 345
 346 /* end of plugin_block_fs.c */