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 it
   6      under the terms of the GNU General Public License as published
   7      by the Free Software Foundation, either version 3 of the License,
   8      or (at your 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      Affero General Public License for more details.
  14 */
  15
  16 /**
  17  * @file consensus/plugin_block_consensus.c
  18  * @brief consensus block, either nested block or marker
  19  * @author Christian Grothoff
  20  */
  21
  22 #include "platform.h"
  23 #include "consensus_protocol.h"
  24 #include "gnunet_block_plugin.h"
  25 #include "gnunet_block_group_lib.h"
  26
  27
  28 /**
  29  * Function called to validate a reply or a request.  For
  30  * request evaluation, simply pass "NULL" for the reply_block.
  31  *
  32  * @param cls closure
  33  * @param ctx context
  34  * @param type block type
  35  * @param group block group to use
  36  * @param eo control flags
  37  * @param query original query (hash)
  38  * @param xquery extrended query data (can be NULL, depending on type)
  39  * @param xquery_size number of bytes in xquery
  40  * @param reply_block response to validate
  41  * @param reply_block_size number of bytes in reply block
  42  * @return characterization of result
  43  */
  44 static enum GNUNET_BLOCK_EvaluationResult
  45 block_plugin_consensus_evaluate (void *cls,
  46                                  struct GNUNET_BLOCK_Context *ctx,
  47                                  enum GNUNET_BLOCK_Type type,
  48                                  struct GNUNET_BLOCK_Group *group,
  49                                  enum GNUNET_BLOCK_EvaluationOptions eo,
  50                                  const struct GNUNET_HashCode *query,
  51                                  const void *xquery,
  52                                  size_t xquery_size,
  53                                  const void *reply_block,
  54                                  size_t reply_block_size)
  55 {
  56   if (reply_block_size < sizeof (struct ConsensusElement))
  57     return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  58
  59   const struct ConsensusElement *ce = reply_block;
  60
  61   if ( (0 != ce->marker) ||
  62        (0 == ce->payload_type ) )
  63     return GNUNET_BLOCK_EVALUATION_OK_MORE;
  64
  65   return GNUNET_BLOCK_evaluate (ctx,
  66                                 type,
  67                                 group,
  68                                 eo,
  69                                 query,
  70                                 xquery,
  71                                 xquery_size,
  72                                 &ce[1],
  73                                 reply_block_size - sizeof (struct ConsensusElement));
  74 }
  75
  76
  77 /**
  78  * Function called to obtain the key for a block.
  79  *
  80  * @param cls closure
  81  * @param type block type
  82  * @param block block to get the key for
  83  * @param block_size number of bytes in block
  84  * @param key set to the key (query) for the given block
  85  * @return #GNUNET_OK on success, #GNUNET_SYSERR if type not supported
  86  *         (or if extracting a key from a block of this type does not work)
  87  */
  88 static int
  89 block_plugin_consensus_get_key (void *cls,
  90                                enum GNUNET_BLOCK_Type type,
  91                                const void *block,
  92                                size_t block_size,
  93                                struct GNUNET_HashCode *key)
  94 {
  95   return GNUNET_SYSERR;
  96 }
  97
  98
  99 /**
 100  * Entry point for the plugin.
 101  */
 102 void *
 103 libgnunet_plugin_block_consensus_init (void *cls)
 104 {
 105   static enum GNUNET_BLOCK_Type types[] =
 106   {
 107     GNUNET_BLOCK_TYPE_CONSENSUS_ELEMENT,
 108     GNUNET_BLOCK_TYPE_ANY       /* end of list */
 109   };
 110   struct GNUNET_BLOCK_PluginFunctions *api;
 111
 112   api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
 113   api->evaluate = &block_plugin_consensus_evaluate;
 114   api->get_key = &block_plugin_consensus_get_key;
 115   api->types = types;
 116   return api;
 117 }
 118
 119
 120 /**
 121  * Exit point from the plugin.
 122  */
 123 void *
 124 libgnunet_plugin_block_consensus_done (void *cls)
 125 {
 126   struct GNUNET_BLOCK_PluginFunctions *api = cls;
 127
 128   GNUNET_free (api);
 129   return NULL;
 130 }
 131
 132 /* end of plugin_block_consensus.c */