1 files changed, 308 insertions, 0 deletions

diff --git a/src/plugin/dht/plugin_block_dht.c b/src/plugin/dht/plugin_block_dht.c
new file mode 100644
index 000000000..ede23ea57
--- /dev/null
+++ b/src/plugin/dht/plugin_block_dht.c
@@ -0,0 +1,308 @@
+/*
+     This file is part of GNUnet
+     Copyright (C) 2010, 2017, 2022 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     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
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file dht/plugin_block_dht.c
+ * @brief block plugin for DHT internals (right now, find-peer requests only);
+ *        other plugins should be used to store "useful" data in the
+ *        DHT (see fs block plugin)
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_constants.h"
+#include "gnunet_hello_uri_lib.h"
+#include "gnunet_block_plugin.h"
+#include "gnunet_block_group_lib.h"
+
+#define DEBUG_DHT GNUNET_EXTRA_LOGGING
+
+/**
+ * Number of bits we set per entry in the bloomfilter.
+ * Do not change!
+ */
+#define BLOOMFILTER_K 16
+
+
+/**
+ * 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 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
+ * @param va variable arguments specific to @a type
+ * @return block group handle, NULL if block groups are not supported
+ *         by this @a type of block (this is not an error)
+ */
+static struct GNUNET_BLOCK_Group *
+block_plugin_dht_create_group (void *cls,
+                               enum GNUNET_BLOCK_Type type,
+                               const void *raw_data,
+                               size_t raw_data_size,
+                               va_list va)
+{
+  unsigned int bf_size;
+  const char *guard;
+
+  guard = va_arg (va, const char *);
+  if (0 == strcmp (guard,
+                   "seen-set-size"))
+    bf_size = GNUNET_BLOCK_GROUP_compute_bloomfilter_size (va_arg (va,
+                                                                   unsigned int),
+                                                           BLOOMFILTER_K);
+  else if (0 == strcmp (guard,
+                        "filter-size"))
+    bf_size = va_arg (va, unsigned int);
+  else
+  {
+    GNUNET_break (0);
+    bf_size = 8;
+  }
+  GNUNET_break (NULL == va_arg (va, const char *));
+  return GNUNET_BLOCK_GROUP_bf_create (cls,
+                                       bf_size,
+                                       BLOOMFILTER_K,
+                                       type,
+                                       raw_data,
+                                       raw_data_size);
+}
+
+
+/**
+ * Function called to validate a query.
+ *
+ * @param cls closure
+ * @param type block type
+ * @param query original query (hash)
+ * @param xquery extrended query data (can be NULL, depending on type)
+ * @param xquery_size number of bytes in @a xquery
+ * @return #GNUNET_OK if the query is fine, #GNUNET_NO if not
+ */
+static enum GNUNET_GenericReturnValue
+block_plugin_dht_check_query (void *cls,
+                              enum GNUNET_BLOCK_Type type,
+                              const struct GNUNET_HashCode *query,
+                              const void *xquery,
+                              size_t xquery_size)
+{
+  switch (type)
+  {
+  case GNUNET_BLOCK_TYPE_DHT_HELLO:
+    if (0 != xquery_size)
+    {
+      GNUNET_break_op (0);
+      return GNUNET_NO;
+    }
+    return GNUNET_OK;
+  default:
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * Function called to validate a block for storage.
+ *
+ * @param cls closure
+ * @param type block type
+ * @param block block data to validate
+ * @param block_size number of bytes in @a block
+ * @return #GNUNET_OK if the block is fine, #GNUNET_NO if not
+ */
+static enum GNUNET_GenericReturnValue
+block_plugin_dht_check_block (void *cls,
+                              enum GNUNET_BLOCK_Type type,
+                              const void *block,
+                              size_t block_size)
+{
+  switch (type)
+  {
+  case GNUNET_BLOCK_TYPE_DHT_HELLO:
+    {
+      struct GNUNET_HELLO_Builder *b;
+      const struct GNUNET_PeerIdentity *pid;
+      struct GNUNET_HashCode h_pid;
+
+      b = GNUNET_HELLO_builder_from_block (block,
+                                           block_size);
+      if (NULL == b)
+      {
+        GNUNET_break (0);
+        return GNUNET_NO;
+      }
+      pid = GNUNET_HELLO_builder_iterate (b,
+                                          NULL, NULL);
+      GNUNET_CRYPTO_hash (pid,
+                          sizeof (*pid),
+                          &h_pid);
+      GNUNET_HELLO_builder_free (b);
+      return GNUNET_OK;
+    }
+  default:
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * Function called to validate a reply to a request.  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 GetKeyFunction and the
+ * BlockEvaluationFunction.
+ *
+ * @param cls closure
+ * @param type block type
+ * @param group which block group to use for evaluation
+ * @param query original query (hash)
+ * @param xquery extrended 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
+ */
+static enum GNUNET_BLOCK_ReplyEvaluationResult
+block_plugin_dht_check_reply (
+  void *cls,
+  enum GNUNET_BLOCK_Type type,
+  struct GNUNET_BLOCK_Group *group,
+  const struct GNUNET_HashCode *query,
+  const void *xquery,
+  size_t xquery_size,
+  const void *reply_block,
+  size_t reply_block_size)
+{
+  switch (type)
+  {
+  case GNUNET_BLOCK_TYPE_DHT_HELLO:
+    {
+      struct GNUNET_HELLO_Builder *b;
+      const struct GNUNET_PeerIdentity *pid;
+      struct GNUNET_HashCode h_pid;
+
+      b = GNUNET_HELLO_builder_from_block (reply_block,
+                                           reply_block_size);
+      GNUNET_assert (NULL != b);
+      pid = GNUNET_HELLO_builder_iterate (b,
+                                          NULL, NULL);
+      GNUNET_CRYPTO_hash (pid,
+                          sizeof (*pid),
+                          &h_pid);
+      GNUNET_HELLO_builder_free (b);
+      if (GNUNET_YES ==
+          GNUNET_BLOCK_GROUP_bf_test_and_set (group,
+                                              &h_pid))
+        return GNUNET_BLOCK_REPLY_OK_DUPLICATE;
+      return GNUNET_BLOCK_REPLY_OK_MORE;
+    }
+  default:
+    return GNUNET_BLOCK_REPLY_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 @a block
+ * @param[out] 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 enum GNUNET_GenericReturnValue
+block_plugin_dht_get_key (void *cls,
+                          enum GNUNET_BLOCK_Type type,
+                          const void *block,
+                          size_t block_size,
+                          struct GNUNET_HashCode *key)
+{
+  switch (type)
+  {
+  case GNUNET_BLOCK_TYPE_DHT_HELLO:
+    {
+      struct GNUNET_HELLO_Builder *b;
+      const struct GNUNET_PeerIdentity *pid;
+
+      b = GNUNET_HELLO_builder_from_block (block,
+                                           block_size);
+      if (NULL == b)
+      {
+        GNUNET_break (0);
+        memset (key,
+                0,
+                sizeof (*key));
+        return GNUNET_OK;
+      }
+      pid = GNUNET_HELLO_builder_iterate (b,
+                                          NULL, NULL);
+      GNUNET_CRYPTO_hash (pid,
+                          sizeof (*pid),
+                          key);
+      GNUNET_HELLO_builder_free (b);
+      return GNUNET_OK;
+    }
+  default:
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+}
+
+
+/**
+ * Entry point for the plugin.
+ */
+void *
+libgnunet_plugin_block_dht_init (void *cls)
+{
+  static enum GNUNET_BLOCK_Type types[] = {
+    GNUNET_BLOCK_TYPE_DHT_HELLO,
+    GNUNET_BLOCK_TYPE_ANY       /* end of list */
+  };
+  struct GNUNET_BLOCK_PluginFunctions *api;
+
+  api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
+  api->get_key = &block_plugin_dht_get_key;
+  api->check_query = &block_plugin_dht_check_query;
+  api->check_block = &block_plugin_dht_check_block;
+  api->check_reply = &block_plugin_dht_check_reply;
+  api->create_group = &block_plugin_dht_create_group;
+  api->types = types;
+  return api;
+}
+
+
+/**
+ * Exit point from the plugin.
+ */
+void *
+libgnunet_plugin_block_dht_done (void *cls)
+{
+  struct GNUNET_BLOCK_PluginFunctions *api = cls;
+
+  GNUNET_free (api);
+  return NULL;
+}
+
+
+/* end of plugin_block_dht.c */