Link libgnunetblockgroup to libgnunetblock
[oweals/gnunet.git] / src / block / block.c
index 24dab79077e2aa900c50a731f413dd2337250063..23caacd382f37a97d4c539361e1a1e213891abfa 100644 (file)
@@ -1,10 +1,10 @@
 /*
      This file is part of GNUnet.
-     (C) 2010 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2010, 2017 GNUnet e.V.
 
      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 2, or (at your
+     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
@@ -14,8 +14,8 @@
 
      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.
+     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
 */
 
 /**
  */
 #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;
+};
+
 
 /**
- * Check if the given KBlock is well-formed.
+ * Mingle hash with the mingle_number to produce different bits.
  *
- * @param kb the kblock data (or at least "dsize" bytes claiming to be one)
- * @param dsize size of "kb" in bytes; check for < sizeof(struct KBlock)!
- * @param query where to store the query that this block answers
- * @return GNUNET_OK if this is actually a well-formed KBlock
+ * @param in original hash code
+ * @param mingle_number number for hash permutation
+ * @param hc where to store the result.
  */
-static int
-check_kblock (const struct KBlock *kb,
-             size_t dsize,
-             GNUNET_HashCode *query)
+void
+GNUNET_BLOCK_mingle_hash (const struct GNUNET_HashCode *in,
+                         uint32_t mingle_number,
+                          struct GNUNET_HashCode *hc)
 {
-  if (dsize < sizeof (struct KBlock))
-    {
-      GNUNET_break_op (0);
-      return GNUNET_SYSERR;
-    }
-  if (dsize - 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 (query != NULL)
-    GNUNET_CRYPTO_hash (&kb->keyspace,
-                       sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
-                       query);
-  return GNUNET_OK;
+  struct GNUNET_HashCode m;
+
+  GNUNET_CRYPTO_hash (&mingle_number,
+                      sizeof (uint32_t),
+                      &m);
+  GNUNET_CRYPTO_hash_xor (&m,
+                          in,
+                          hc);
 }
 
 
 /**
- * Check if the given NBlock is well-formed.
+ * Add a plugin to the list managed by the block library.
  *
- * @param nb the nblock data (or at least "dsize" bytes claiming to be one)
- * @param dsize size of "nb" in bytes; check for < sizeof(struct NBlock)!
- * @param query where to store the query that this block answers
- * @return GNUNET_OK if this is actually a well-formed NBlock
+ * @param cls the block context
+ * @param library_name name of the plugin
+ * @param lib_ret the plugin API
  */
-static int
-check_nblock (const struct NBlock *nb,
-             size_t dsize,
-             GNUNET_HashCode *query)
+static void
+add_plugin (void *cls,
+           const char *library_name,
+           void *lib_ret)
 {
-  if (dsize < sizeof (struct NBlock))
-    {
-      GNUNET_break_op (0);
-      return GNUNET_SYSERR;
-    }
-  if (dsize - 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 (dsize !=
-      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;
-    }
-  if (query != NULL)
-    GNUNET_CRYPTO_hash (&nb->keyspace,
-                       sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
-                       query);
-  return GNUNET_OK;
+  struct GNUNET_BLOCK_Context *ctx = cls;
+  struct GNUNET_BLOCK_PluginFunctions *api = lib_ret;
+  struct Plugin *plugin;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Loading block plugin `%s'\n",
+              library_name);
+  plugin = GNUNET_new (struct Plugin);
+  plugin->api = api;
+  plugin->library_name = GNUNET_strdup (library_name);
+  GNUNET_array_append (ctx->plugins,
+                       ctx->num_plugins,
+                       plugin);
 }
 
 
+
 /**
- * Check if the given SBlock is well-formed.
+ * Create a block context.  Loads the block plugins.
  *
- * @param sb the sblock data (or at least "dsize" bytes claiming to be one)
- * @param dsize size of "kb" in bytes; check for < sizeof(struct SBlock)!
- * @param query where to store the query that this block answers
- * @return GNUNET_OK if this is actually a well-formed SBlock
+ * @param cfg configuration to use
+ * @return NULL on error
  */
-static int
-check_sblock (const struct SBlock *sb,
-             size_t dsize,
-             GNUNET_HashCode *query)
+struct GNUNET_BLOCK_Context *
+GNUNET_BLOCK_context_create (const struct GNUNET_CONFIGURATION_Handle *cfg)
 {
-  if (dsize < sizeof (struct SBlock))
-    {
-      GNUNET_break_op (0);
-      return GNUNET_SYSERR;
-    }
-  if (dsize !=
-      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 (query != NULL)
-    *query = sb->identifier;
-  return GNUNET_OK;
+  struct GNUNET_BLOCK_Context *ctx;
+
+  ctx = GNUNET_new (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);
+}
+
+
+/**
+ * Serialize state of a block group.
+ *
+ * @param bg group to serialize
+ * @param[out] nonce set to the nonce of the @a bg
+ * @param[out] raw_data set to the serialized state
+ * @param[out] raw_data_size set to the number of bytes in @a raw_data
+ * @return #GNUNET_OK on success, #GNUNET_NO if serialization is not
+ *         supported, #GNUNET_SYSERR on error
+ */
+int
+GNUNET_BLOCK_group_serialize (struct GNUNET_BLOCK_Group *bg,
+                              uint32_t *nonce,
+                              void **raw_data,
+                              size_t *raw_data_size)
+{
+  *nonce = 0;
+  *raw_data = NULL;
+  *raw_data_size = 0;
+  if (NULL == bg)
+    return GNUNET_NO;
+  if (NULL == bg->serialize_cb)
+    return GNUNET_NO;
+  return bg->serialize_cb (bg,
+                           nonce,
+                           raw_data,
+                           raw_data_size);
+}
+
+
+/**
+ * Destroy resources used by a block group.
+ *
+ * @param bg group to destroy, NULL is allowed
+ */
+void
+GNUNET_BLOCK_group_destroy (struct GNUNET_BLOCK_Group *bg)
+{
+  if (NULL == bg)
+    return;
+  bg->destroy_cb (bg);
 }
 
 
 /**
- * Check if the given block is well-formed (and of the given type).
+ * Try merging two block groups.  Afterwards, @a bg1 should remain
+ * valid and contain the rules from both @a bg1 and @bg2, and
+ * @a bg2 should be destroyed (as part of this call).  The latter
+ * should happen even if merging is not supported.
  *
- * @param type type of the block
- * @param block the block data (or at least "size" bytes claiming to be one)
- * @param size size of "kb" in bytes; check that it is large enough
- * @param query where to store the query that this block answers
- * @return GNUNET_OK if this is actually a well-formed block,
- *         GNUNET_NO if we could not determine the query,
- *         GNUNET_SYSERR if the block is malformed
+ * @param[in,out] bg1 first group to merge, is updated
+ * @param bg2 second group to merge, is destroyed
+ * @return #GNUNET_OK on success,
+ *         #GNUNET_NO if merge failed due to different nonce
+ *         #GNUNET_SYSERR if merging is not supported
  */
 int
-GNUNET_BLOCK_check_block (enum GNUNET_BLOCK_Type type,
-                         const void *block,
-                         size_t size,
-                         GNUNET_HashCode *query)
+GNUNET_BLOCK_group_merge (struct GNUNET_BLOCK_Group *bg1,
+                          struct GNUNET_BLOCK_Group *bg2)
 {
-  /* first, validate! */
-  switch (type)
+  int ret;
+
+  if (NULL == bg2)
+    return GNUNET_OK;
+  if (NULL == bg1)
+  {
+    bg2->destroy_cb (bg2);
+    return GNUNET_OK;
+  }
+  if (NULL == bg1->merge_cb)
+    return GNUNET_SYSERR;
+  GNUNET_assert (bg1->merge_cb == bg1->merge_cb);
+  ret = bg1->merge_cb (bg1,
+                       bg2);
+  bg2->destroy_cb (bg2);
+  return ret;
+}
+
+
+/**
+ * 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 j;
+
+  for (unsigned i = 0; i < ctx->num_plugins; i++)
+  {
+    plugin = ctx->plugins[i];
+    j = 0;
+    while (0 != (plugin->api->types[j]))
     {
-    case GNUNET_BLOCK_TYPE_DBLOCK:
-    case GNUNET_BLOCK_TYPE_IBLOCK:
-      GNUNET_CRYPTO_hash (block, size, query);
-      break;
-    case GNUNET_BLOCK_TYPE_KBLOCK:
-      if (GNUNET_OK !=
-         check_kblock (block,
-                       size,
-                       query))
-       return GNUNET_SYSERR;
-      break;
-    case GNUNET_BLOCK_TYPE_SBLOCK:
-      if (GNUNET_OK !=
-         check_sblock (block,
-                       size,
-                       query))
-       return GNUNET_SYSERR;
-      break;
-    case GNUNET_BLOCK_TYPE_NBLOCK:
-      if (GNUNET_OK !=
-         check_nblock (block,
-                       size,
-                       query))
-       return GNUNET_SYSERR;
-      return GNUNET_OK;
-    case GNUNET_BLOCK_TYPE_ONDEMAND:
-      if (size != sizeof (struct OnDemandBlock))
-       return GNUNET_SYSERR;
-      memset (query, 0, sizeof (GNUNET_HashCode));      
-      return GNUNET_NO;
-    default:
-      /* unknown block type */
-      GNUNET_break_op (0);
-      return GNUNET_SYSERR;
+      if (type == plugin->api->types[j])
+        return plugin->api;
+      j++;
     }
+  }
+  return NULL;
+}
+
+
+/**
+ * Create a new block group.
+ *
+ * @param ctx block context in which the block group is created
+ * @param type type of the block for which we are creating the group
+ * @param nonce random value used to seed the group creation
+ * @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
+ * @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
+ * @return block group handle, NULL if block groups are not supported
+ *         by this @a type of block (this is not an error)
+ */
+struct GNUNET_BLOCK_Group *
+GNUNET_BLOCK_group_create (struct GNUNET_BLOCK_Context *ctx,
+                           enum GNUNET_BLOCK_Type type,
+                           uint32_t nonce,
+                           const void *raw_data,
+                           size_t raw_data_size,
+                           ...)
+{
+  struct GNUNET_BLOCK_PluginFunctions *plugin;
+  struct GNUNET_BLOCK_Group *bg;
+  va_list ap;
+
+  plugin = find_plugin (ctx,
+                        type);
+  if (NULL == plugin->create_group)
+    return NULL;
+  va_start (ap,
+            raw_data_size);
+  bg = plugin->create_group (plugin->cls,
+                             type,
+                             nonce,
+                             raw_data,
+                             raw_data_size,
+                             ap);
+  va_end (ap);
+  return bg;
+}
+
+
+/**
+ * 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 block block group to use
+ * @param eo control flags
+ * @param query original query (hash)
+ * @param xquery extended query data (can be NULL, depending on type)
+ * @param xquery_size number of bytes in @a xquery
+ * @param reply_block response to validate
+ * @param reply_block_size number of bytes in @a reply_block
+ * @return characterization of result
+ */
+enum GNUNET_BLOCK_EvaluationResult
+GNUNET_BLOCK_evaluate (struct GNUNET_BLOCK_Context *ctx,
+                       enum GNUNET_BLOCK_Type type,
+                       struct GNUNET_BLOCK_Group *group,
+                       enum GNUNET_BLOCK_EvaluationOptions eo,
+                       const struct GNUNET_HashCode *query,
+                       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 (NULL == plugin)
+    return GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
+  return plugin->evaluate (plugin->cls,
+                           type,
+                           group,
+                           eo,
+                           query,
+                           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 @a 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,
+                      struct 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);
+}
+
+
+/**
+ * Update block group to filter out the given results.  Note that the
+ * use of a hash for seen results implies that the caller magically
+ * knows how the specific block engine hashes for filtering
+ * duplicates, so this API may not always apply.
+ *
+ * @param bf_mutator mutation value to use
+ * @param seen_results results already seen
+ * @param seen_results_count number of entries in @a seen_results
+ * @return #GNUNET_SYSERR if not supported, #GNUNET_OK on success
+ */
+int
+GNUNET_BLOCK_group_set_seen (struct GNUNET_BLOCK_Group *bg,
+                             const struct GNUNET_HashCode *seen_results,
+                             unsigned int seen_results_count)
+{
+  if (NULL == bg)
+    return GNUNET_OK;
+  if (NULL == bg->mark_seen_cb)
+    return GNUNET_SYSERR;
+  bg->mark_seen_cb (bg,
+                    seen_results,
+                    seen_results_count);
   return GNUNET_OK;
 }