src/consensus/plugin_block_consensus.c

   1 /*
   2      This file is part of GNUnet
   3      Copyright (C) 2017 GNUnet e.V.
   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., 51 Franklin Street, Fifth Floor,
  18      Boston, MA 02110-1301, USA.
  19 */
  20
  21 /**
  22  * @file consensus/plugin_block_consensus.c
  23  * @brief consensus block, either nested block or marker
  24  * @author Christian Grothoff
  25  */
  26
  27 #include "platform.h"
  28 #include "consensus_protocol.h"
  29 #include "gnunet_block_plugin.h"
  30 #include "gnunet_block_group_lib.h"
  31
  32
  33 /**
  34  * Function called to validate a reply or a request.  For
  35  * request evaluation, simply pass "NULL" for the reply_block.
  36  *
  37  * @param cls closure
  38  * @param ctx context
  39  * @param type block type
  40  * @param group block group to use
  41  * @param eo control flags
  42  * @param query original query (hash)
  43  * @param xquery extrended query data (can be NULL, depending on type)
  44  * @param xquery_size number of bytes in xquery
  45  * @param reply_block response to validate
  46  * @param reply_block_size number of bytes in reply block
  47  * @return characterization of result
  48  */
  49 static enum GNUNET_BLOCK_EvaluationResult
  50 block_plugin_consensus_evaluate (void *cls,
  51                                  struct GNUNET_BLOCK_Context *ctx,
  52                                  enum GNUNET_BLOCK_Type type,
  53                                  struct GNUNET_BLOCK_Group *group,
  54                                  enum GNUNET_BLOCK_EvaluationOptions eo,
  55                                  const struct GNUNET_HashCode *query,
  56                                  const void *xquery,
  57                                  size_t xquery_size,
  58                                  const void *reply_block,
  59                                  size_t reply_block_size)
  60 {
  61   if (reply_block_size < sizeof (struct ConsensusElement))
  62     return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  63
  64   const struct ConsensusElement *ce = reply_block;
  65
  66   if ( (0 != ce->marker) ||
  67        (0 == ce->payload_type ) )
  68     return GNUNET_BLOCK_EVALUATION_OK_MORE;
  69
  70   return GNUNET_BLOCK_evaluate (ctx,
  71                                 type,
  72                                 group,
  73                                 eo,
  74                                 query,
  75                                 xquery,
  76                                 xquery_size,
  77                                 &ce[1],
  78                                 reply_block_size - sizeof (struct ConsensusElement));
  79 }
  80
  81
  82 /**
  83  * Function called to obtain the key for a block.
  84  *
  85  * @param cls closure
  86  * @param type block type
  87  * @param block block to get the key for
  88  * @param block_size number of bytes in block
  89  * @param key set to the key (query) for the given block
  90  * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
  91  *         (or if extracting a key from a block of this type does not work)
  92  */
  93 static int
  94 block_plugin_consensus_get_key (void *cls,
  95                                enum GNUNET_BLOCK_Type type,
  96                                const void *block,
  97                                size_t block_size,
  98                                struct GNUNET_HashCode *key)
  99 {
 100   return GNUNET_SYSERR;
 101 }
 102
 103
 104 /**
 105  * Entry point for the plugin.
 106  */
 107 void *
 108 libgnunet_plugin_block_consensus_init (void *cls)
 109 {
 110   static enum GNUNET_BLOCK_Type types[] =
 111   {
 112     GNUNET_BLOCK_TYPE_CONSENSUS_ELEMENT,
 113     GNUNET_BLOCK_TYPE_ANY       /* end of list */
 114   };
 115   struct GNUNET_BLOCK_PluginFunctions *api;
 116
 117   api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
 118   api->evaluate = &block_plugin_consensus_evaluate;
 119   api->get_key = &block_plugin_consensus_get_key;
 120   api->types = types;
 121   return api;
 122 }
 123
 124
 125 /**
 126  * Exit point from the plugin.
 127  */
 128 void *
 129 libgnunet_plugin_block_consensus_done (void *cls)
 130 {
 131   struct GNUNET_BLOCK_PluginFunctions *api = cls;
 132
 133   GNUNET_free (api);
 134   return NULL;
 135 }
 136
 137 /* end of plugin_block_consensus.c */