towards pluggable block library

1 files changed, 346 insertions, 0 deletions

diff --git a/src/block/plugin_block_fs.c b/src/block/plugin_block_fs.c
new file mode 100644
index 000000000..362932991
--- /dev/null
+++ b/src/block/plugin_block_fs.c
@@ -0,0 +1,346 @@
+/*
+     This file is part of GNUnet
+     (C) 2010 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 3, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file block/plugin_block_fs.c
+ * @brief blocks used for file-sharing
+ * @author Christian Grothoff
+ */
+
+#include "platform.h"
+#include "plugin_block.h"
+#include "gnunet_signatures.h"
+
+#define DEBUG_FS_BLOCK GNUNET_NO
+
+/**
+ * Number of bits we set per entry in the bloomfilter.
+ * Do not change!
+ */
+#define BLOOMFILTER_K 16
+
+/**
+ * Mingle hash with the mingle_number to produce different bits.
+ */
+static void
+mingle_hash (const GNUNET_HashCode * in,
+             int32_t mingle_number, 
+             GNUNET_HashCode * hc)
+{
+  GNUNET_HashCode m;
+
+  GNUNET_CRYPTO_hash (&mingle_number, 
+                      sizeof (int32_t), 
+                      &m);
+  GNUNET_CRYPTO_hash_xor (&m, in, hc);
+}
+
+
+/**
+ * Function called to validate a reply or a request.  For
+ * request evaluation, simply pass "NULL" for the reply_block.
+ * Note that it is assumed that the reply has already been 
+ * matched to the key (and signatures checked) as it would
+ * be done with the "get_key" function.
+ *
+ * @param cls closure
+ * @param type block type
+ * @param query original query (hash)
+ * @param bf pointer to bloom filter associated with query; possibly updated (!)
+ * @param bf_mutator mutation value for bf
+ * @param xquery extrended query data (can be NULL, depending on type)
+ * @param xquery_size number of bytes in xquery
+ * @param reply_block response to validate
+ * @param reply_block_size number of bytes in reply block
+ * @return characterization of result
+ */
+static enum GNUNET_BLOCK_EvaluationResult
+block_plugin_fs_evaluate (void *cls,
+                          enum GNUNET_BLOCK_Type type,
+                          const GNUNET_HashCode *query,
+                          struct GNUNET_CONTAINER_BloomFilter **bf,
+                          int32_t bf_mutator,
+                          const void *xquery,
+                          size_t xquery_size,
+                          const void *reply_block,
+                          size_t reply_block_size)
+{
+  const struct SBlock *sb;
+  GNUNET_HashCode chash;
+  GNUNET_HashCode mhash;
+  const GNUNET_HashCode *nsid;
+  GNUNET_HashCode sh;
+
+  switch (type)
+    {
+    case GNUNET_BLOCK_TYPE_DBLOCK:
+    case GNUNET_BLOCK_TYPE_IBLOCK:
+      if (xquery_size != 0) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
+        }
+      return GNUNET_BLOCK_EVALUATION_OK_LAST;
+    case GNUNET_BLOCK_TYPE_KBLOCK:
+    case GNUNET_BLOCK_TYPE_NBLOCK:
+      if (xquery_size != 0) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
+        }
+      if (reply_block == NULL)
+        return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
+      GNUNET_CRYPTO_hash (reply_block,
+                          reply_block_size,
+                          &chash);
+      mingle_hash (&chash, bf_mutator, &mhash);
+      if (NULL != *bf)
+        {
+          if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
+                                                               &mhash))
+            return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
+        }
+      else
+        {
+          *bf = GNUNET_CONTAINER_bloomfilter_init (NULL, 
+                                                   8,
+                                                   BLOOMFILTER_K);
+        }
+      GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
+      return GNUNET_BLOCK_EVALUATION_OK_MORE;
+    case GNUNET_BLOCK_TYPE_SBLOCK:
+      if (xquery_size != sizeof (GNUNET_HashCode)) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
+        }
+      if (reply_block == NULL)
+        return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
+      nsid = xquery;
+      if (reply_block_size < sizeof (struct NBlock))
+        return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
+      sb = reply_block;
+      GNUNET_CRYPTO_hash (&sb->subspace,
+                          sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+                          &sh);
+      if (0 != memcmp (nsid,
+                       &sh,
+                       sizeof (GNUNET_HashCode)))
+        {
+          GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                      _("Reply mismatched in terms of namespace.  Discarded.\n"));
+          return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
+        }
+      GNUNET_CRYPTO_hash (reply_block,
+                          reply_block_size,
+                          &chash);
+      mingle_hash (&chash, bf_mutator, &mhash);
+      if (NULL != *bf)
+        {
+          if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (*bf,
+                                                               &mhash))
+            return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
+        }
+      else
+        {
+          *bf = GNUNET_CONTAINER_bloomfilter_init (NULL, 
+                                                   8,
+                                                   BLOOMFILTER_K);
+        }
+      GNUNET_CONTAINER_bloomfilter_add (*bf, &mhash);
+      return GNUNET_BLOCK_EVALUATION_OK_MORE;
+    default:
+      return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
+    }
+}
+
+
+/**
+ * Function called to obtain the key for a block.
+ *
+ * @param cls closure
+ * @param type block type
+ * @param block block to get the key for
+ * @param block_size number of bytes in block
+ * @param key set to the key (query) for the given block
+ * @return GNUNET_OK on success, GNUNET_SYSERR if type not supported
+ *         (or if extracting a key from a block of this type does not work)
+ */
+static int
+block_plugin_fs_get_key (void *cls,
+                         enum GNUNET_BLOCK_Type type,
+                         const void *block,
+                         size_t block_size,
+                         GNUNET_HashCode *key)
+{
+  const struct KBlock *kb;
+  const struct SBlock *sb;
+  const struct NBlock *nb;
+
+  switch (type)
+    {
+    case GNUNET_BLOCK_TYPE_DBLOCK:
+    case GNUNET_BLOCK_TYPE_IBLOCK:
+      GNUNET_CRYPTO_hash (block, block_size, key);
+      return GNUNET_OK;
+    case GNUNET_BLOCK_TYPE_KBLOCK:
+      if (block_size < sizeof (struct KBlock))
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      kb = block;
+      if (block_size - sizeof (struct KBlock) !=
+          ntohl (kb->purpose.size) 
+          - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) 
+          - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) ) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (GNUNET_OK !=
+          GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_KBLOCK,
+                                    &kb->purpose,
+                                    &kb->signature,
+                                    &kb->keyspace)) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (key != NULL)
+        GNUNET_CRYPTO_hash (&kb->keyspace,
+                            sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+                            key);
+      return GNUNET_OK;
+    case GNUNET_BLOCK_TYPE_SBLOCK:
+      if (block_size < sizeof (struct SBlock))
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      sb = block;
+      if (block_size !=
+          ntohl (sb->purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (GNUNET_OK !=
+          GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_SBLOCK,
+                                    &sb->purpose,
+                                    &sb->signature,
+                                    &sb->subspace)) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (key != NULL)
+        *key = sb->identifier;
+      return GNUNET_OK;
+    case GNUNET_BLOCK_TYPE_NBLOCK:
+      if (block_size < sizeof (struct NBlock))
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      nb = block;
+      if (block_size - sizeof (struct NBlock) !=
+          ntohl (nb->ns_purpose.size) 
+          - sizeof (struct GNUNET_CRYPTO_RsaSignaturePurpose) 
+          - sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) ) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (block_size !=
+          ntohl (nb->ksk_purpose.size) + sizeof (struct GNUNET_CRYPTO_RsaSignature))
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (GNUNET_OK !=
+          GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK_KSIG,
+                                    &nb->ksk_purpose,
+                                    &nb->ksk_signature,
+                                    &nb->keyspace)) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      if (GNUNET_OK !=
+          GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_FS_NBLOCK,
+                                    &nb->ns_purpose,
+                                    &nb->ns_signature,
+                                    &nb->subspace)) 
+        {
+          GNUNET_break_op (0);
+          return GNUNET_SYSERR;
+        }
+      /* FIXME: we used to xor ID with NSID,
+         why not here? */
+      if (key != NULL)
+        GNUNET_CRYPTO_hash (&nb->keyspace,
+                            sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+                            key);
+      return GNUNET_OK;
+    default:
+      return GNUNET_SYSERR;
+    }
+}
+                                  
+
+/**
+ * Entry point for the plugin.
+ */
+void *
+gnunet_plugin_block_fs_init (void *cls)
+{
+  static enum GNUNET_BLOCK_Type types[] = 
+    {
+      GNUNET_BLOCK_TYPE_DBLOCK,
+      GNUNET_BLOCK_TYPE_IBLOCK,
+      GNUNET_BLOCK_TYPE_KBLOCK,
+      GNUNET_BLOCK_TYPE_SBLOCK,
+      GNUNET_BLOCK_TYPE_NBLOCK,
+      GNUNET_BLOCK_TYPE_ANY /* end of list */
+    };
+  struct GNUNET_BLOCK_PluginFunctions *api;
+
+  api = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_PluginFunctions));
+  api->evaluate = &block_plugin_fs_evaluate;
+  api->get_key = &block_plugin_fs_get_key;
+  api->types = types;
+  return api;
+}
+
+
+/**
+ * Exit point from the plugin.
+ */
+void *
+gnunet_plugin_block_fs_done (void *cls)
+{
+  struct GNUNET_TRANSPORT_PluginFunctions *api = cls;
+
+  GNUNET_free (api);
+  return NULL;
+}
+
+/* end of plugin_block_fs.c */