plugin_block_dns.c

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/*
     This file is part of GNUnet
     Copyright (C) 2013, 2017 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
 */
 
#include "platform.h"
#include "gnunet_block_plugin.h"
#include "block_dns.h"
#include "gnunet_signatures.h"
#include "gnunet_block_group_lib.h"
 
 
#define BLOOMFILTER_K 16
 
 
static struct GNUNET_BLOCK_Group *
block_plugin_dns_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);
}
 
 
static enum GNUNET_GenericReturnValue
block_plugin_dns_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_DNS:
    if (0 != xquery_size)
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    return GNUNET_OK;
  default:
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
}
 
 
static enum GNUNET_GenericReturnValue
block_plugin_dns_check_block (void *cls,
                              enum GNUNET_BLOCK_Type type,
                              const void *block,
                              size_t block_size)
{
  const struct GNUNET_DNS_Advertisement *ad;
 
  switch (type)
  {
  case GNUNET_BLOCK_TYPE_DNS:
    if (sizeof(struct GNUNET_DNS_Advertisement) != block_size)
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    ad = block;
 
    if (ntohl (ad->purpose.size) !=
        sizeof(struct GNUNET_DNS_Advertisement)
        - sizeof(struct GNUNET_CRYPTO_EddsaSignature))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    if (GNUNET_TIME_absolute_is_past (
          GNUNET_TIME_absolute_ntoh (ad->expiration_time)))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "DNS advertisement has expired\n");
      return GNUNET_NO;
    }
    if (GNUNET_OK !=
        GNUNET_CRYPTO_eddsa_verify_ (GNUNET_SIGNATURE_PURPOSE_DNS_RECORD,
                                     &ad->purpose,
                                     &ad->signature,
                                     &ad->peer.public_key))
    {
      GNUNET_break_op (0);
      return GNUNET_NO;
    }
    return GNUNET_OK;
  default:
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
}
 
 
static enum GNUNET_BLOCK_ReplyEvaluationResult
block_plugin_dns_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)
{
  struct GNUNET_HashCode phash;
 
  switch (type)
  {
  case GNUNET_BLOCK_TYPE_DNS:
    GNUNET_CRYPTO_hash (reply_block,
                        reply_block_size,
                        &phash);
    if (GNUNET_YES ==
        GNUNET_BLOCK_GROUP_bf_test_and_set (group,
                                            &phash))
      return GNUNET_BLOCK_REPLY_OK_DUPLICATE;
    return GNUNET_BLOCK_REPLY_OK_MORE;
  default:
    GNUNET_break (0);
    return GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED;
  }
}
 
 
static enum GNUNET_GenericReturnValue
block_plugin_dns_get_key (void *cls,
                          enum GNUNET_BLOCK_Type type,
                          const void *block,
                          size_t block_size,
                          struct GNUNET_HashCode *key)
{
  if (GNUNET_BLOCK_TYPE_DNS != type)
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_NO;
}
 
 
void *
libgnunet_plugin_block_dns_init (void *cls)
{
  static enum GNUNET_BLOCK_Type types[] = {
    GNUNET_BLOCK_TYPE_DNS,
    GNUNET_BLOCK_TYPE_ANY       /* end of list */
  };
  struct GNUNET_BLOCK_PluginFunctions *api;
 
  api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
  api->get_key = &block_plugin_dns_get_key;
  api->check_query = &block_plugin_dns_check_query;
  api->check_block = &block_plugin_dns_check_block;
  api->check_reply = &block_plugin_dns_check_reply;
  api->create_group = &block_plugin_dns_create_group;
  api->types = types;
  return api;
}
 
 
void *
libgnunet_plugin_block_dns_done (void *cls)
{
  struct GNUNET_BLOCK_PluginFunctions *api = cls;
 
  GNUNET_free (api);
  return NULL;
}
 
 
/* end of plugin_block_dns.c */