1 files changed, 308 insertions, 0 deletions
diff --git a/src/block/block.c b/src/block/block.c
new file mode 100644
index 0000000..7c447f0
--- /dev/null
+++ b/src/block/block.c
@@ -0,0 +1,308 @@
+/*
+     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/block.c
+ * @brief library for data block manipulation
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_signatures.h"
+#include "gnunet_block_lib.h"
+#include "gnunet_block_plugin.h"
+
+
+/**
+ * Handle for a plugin.
+ */
+struct Plugin
+{
+  /**
+   * Name of the shared library.
+   */
+  char *library_name;
+
+  /**
+   * Plugin API.
+   */
+  struct GNUNET_BLOCK_PluginFunctions *api;
+};
+
+
+/**
+ * Handle to an initialized block library.
+ */
+struct GNUNET_BLOCK_Context
+{
+  /**
+   * Array of our plugins.
+   */
+  struct Plugin **plugins;
+
+  /**
+   * Size of the 'plugins' array.
+   */
+  unsigned int num_plugins;
+
+  /**
+   * Our configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+};
+
+
+/**
+ * Mingle hash with the mingle_number to produce different bits.
+ *
+ * @param in original hash code
+ * @param mingle_number number for hash permutation
+ * @param hc where to store the result.
+ */
+void
+GNUNET_BLOCK_mingle_hash (const GNUNET_HashCode * in, uint32_t mingle_number,
+                          GNUNET_HashCode * hc)
+{
+  GNUNET_HashCode m;
+
+  GNUNET_CRYPTO_hash (&mingle_number, sizeof (uint32_t), &m);
+  GNUNET_CRYPTO_hash_xor (&m, in, hc);
+}
+
+
+/**
+ * Add a plugin to the list managed by the block library.
+ *
+ * @param cls the block context
+ * @param library_name name of the plugin
+ * @param lib_ret the plugin API
+ */
+static void
+add_plugin (void *cls, const char *library_name, void *lib_ret)
+{
+  struct GNUNET_BLOCK_Context *ctx = cls;
+  struct GNUNET_BLOCK_PluginFunctions *api = lib_ret;
+  struct Plugin *plugin;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Loading block plugin `%s'\n"),
+              library_name);
+  plugin = GNUNET_malloc (sizeof (struct Plugin));
+  plugin->api = api;
+  plugin->library_name = GNUNET_strdup (library_name);
+  GNUNET_array_append (ctx->plugins, ctx->num_plugins, plugin);
+}
+
+
+
+/**
+ * Create a block context.  Loads the block plugins.
+ *
+ * @param cfg configuration to use
+ * @return NULL on error
+ */
+struct GNUNET_BLOCK_Context *
+GNUNET_BLOCK_context_create (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  struct GNUNET_BLOCK_Context *ctx;
+
+  ctx = GNUNET_malloc (sizeof (struct GNUNET_BLOCK_Context));
+  ctx->cfg = cfg;
+  GNUNET_PLUGIN_load_all ("libgnunet_plugin_block_", NULL, &add_plugin, ctx);
+  return ctx;
+}
+
+
+/**
+ * Destroy the block context.
+ *
+ * @param ctx context to destroy
+ */
+void
+GNUNET_BLOCK_context_destroy (struct GNUNET_BLOCK_Context *ctx)
+{
+  unsigned int i;
+  struct Plugin *plugin;
+
+  for (i = 0; i < ctx->num_plugins; i++)
+  {
+    plugin = ctx->plugins[i];
+    GNUNET_break (NULL ==
+                  GNUNET_PLUGIN_unload (plugin->library_name, plugin->api));
+    GNUNET_free (plugin->library_name);
+    GNUNET_free (plugin);
+  }
+  GNUNET_free (ctx->plugins);
+  GNUNET_free (ctx);
+}
+
+
+/**
+ * Find a plugin for the given type.
+ *
+ * @param ctx context to search
+ * @param type type to look for
+ * @return NULL if no matching plugin exists
+ */
+static struct GNUNET_BLOCK_PluginFunctions *
+find_plugin (struct GNUNET_BLOCK_Context *ctx, enum GNUNET_BLOCK_Type type)
+{
+  struct Plugin *plugin;
+  unsigned int i;
+  unsigned int j;
+
+  for (i = 0; i < ctx->num_plugins; i++)
+  {
+    plugin = ctx->plugins[i];
+    j = 0;
+    while (0 != (plugin->api->types[j]))
+    {
+      if (type == plugin->api->types[j])
+        return plugin->api;
+      j++;
+    }
+  }
+  return NULL;
+}
+
+
+/**
+ * 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 ctx block contxt
+ * @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 extended 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
+ */
+enum GNUNET_BLOCK_EvaluationResult
+GNUNET_BLOCK_evaluate (struct GNUNET_BLOCK_Context *ctx,
+                       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)
+{
+  struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx, type);
+
+  if (plugin == NULL)
+    return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
+  return plugin->evaluate (plugin->cls, type, query, bf, bf_mutator, xquery,
+                           xquery_size, reply_block, reply_block_size);
+}
+
+
+/**
+ * Function called to obtain the key for a block.
+ *
+ * @param ctx block context
+ * @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)
+ */
+int
+GNUNET_BLOCK_get_key (struct GNUNET_BLOCK_Context *ctx,
+                      enum GNUNET_BLOCK_Type type, const void *block,
+                      size_t block_size, GNUNET_HashCode * key)
+{
+  struct GNUNET_BLOCK_PluginFunctions *plugin = find_plugin (ctx, type);
+
+  if (plugin == NULL)
+    return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
+  return plugin->get_key (plugin->cls, type, block, block_size, key);
+}
+
+
+/**
+ * How many bytes should a bloomfilter be if we have already seen
+ * entry_count responses?  Note that GNUNET_CONSTANTS_BLOOMFILTER_K gives us the number
+ * of bits set per entry.  Furthermore, we should not re-size the
+ * filter too often (to keep it cheap).
+ *
+ * Since other peers will also add entries but not resize the filter,
+ * we should generally pick a slightly larger size than what the
+ * strict math would suggest.
+ *
+ * @return must be a power of two and smaller or equal to 2^15.
+ */
+static size_t
+compute_bloomfilter_size (unsigned int entry_count)
+{
+  size_t size;
+  unsigned int ideal = (entry_count * GNUNET_CONSTANTS_BLOOMFILTER_K) / 4;
+  uint16_t max = 1 << 15;
+
+  if (entry_count > max)
+    return max;
+  size = 8;
+  while ((size < max) && (size < ideal))
+    size *= 2;
+  if (size > max)
+    return max;
+  return size;
+}
+
+
+/**
+ * Construct a bloom filter that would filter out the given
+ * results.
+ *
+ * @param bf_mutator mutation value to use
+ * @param seen_results results already seen
+ * @param seen_results_count number of entries in 'seen_results'
+ * @return NULL if seen_results_count is 0, otherwise a BF
+ *         that would match the given results.
+ */
+struct GNUNET_CONTAINER_BloomFilter *
+GNUNET_BLOCK_construct_bloomfilter (int32_t bf_mutator,
+                                    const GNUNET_HashCode * seen_results,
+                                    unsigned int seen_results_count)
+{
+  struct GNUNET_CONTAINER_BloomFilter *bf;
+  GNUNET_HashCode mhash;
+  unsigned int i;
+  size_t nsize;
+
+  nsize = compute_bloomfilter_size (seen_results_count);
+  bf = GNUNET_CONTAINER_bloomfilter_init (NULL, nsize,
+                                          GNUNET_CONSTANTS_BLOOMFILTER_K);
+  for (i = 0; i < seen_results_count; i++)
+  {
+    GNUNET_BLOCK_mingle_hash (&seen_results[i], bf_mutator, &mhash);
+    GNUNET_CONTAINER_bloomfilter_add (bf, &mhash);
+  }
+  return bf;
+}
+
+
+/* end of block.c */