plugin_block_regex.c

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/*
     This file is part of GNUnet
     Copyright (C) 2013 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 "gnunet_block_group_lib.h"
#include "block_regex.h"
#include "regex_block_lib.h"
#include "gnunet_signatures.h"


#define BLOOMFILTER_K 16


#define REGEX_BF_SIZE 8


static struct GNUNET_BLOCK_Group *
block_plugin_regex_create_group (void *cls,
                                 enum GNUNET_BLOCK_Type type,
                                 uint32_t nonce,
                                 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 = REGEX_BF_SIZE;
  }
  GNUNET_break (NULL == va_arg (va, const char *));
  return GNUNET_BLOCK_GROUP_bf_create (cls,
                                       bf_size,
                                       BLOOMFILTER_K,
                                       type,
                                       nonce,
                                       raw_data,
                                       raw_data_size);
}


static enum GNUNET_BLOCK_EvaluationResult
evaluate_block_regex (void *cls,
                      enum GNUNET_BLOCK_Type type,
                      struct GNUNET_BLOCK_Group *bg,
                      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_HashCode chash;

  if (NULL == reply_block)
  {
    if (0 != xquery_size)
      {
        const char *s;

        s = (const char *) xquery;
        if ('\0' != s[xquery_size - 1]) /* must be valid 0-terminated string */
          {
            GNUNET_break_op (0);
            return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
          }
      }
    return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  }
  if (0 != xquery_size)
  {
    const char *s;

    s = (const char *) xquery;
    if ('\0' != s[xquery_size - 1]) /* must be valid 0-terminated string */
    {
      GNUNET_break_op (0);
      return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
    }
  }
  else if (NULL != query)
  {
    /* xquery is required for regex GETs, at least an empty string */
    GNUNET_break_op (0);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "type %d, query %p, xquery %p\n",
                type, query, xquery);
    return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  }
  switch (REGEX_BLOCK_check (reply_block,
                             reply_block_size,
                             query,
                             xquery))
  {
    case GNUNET_SYSERR:
      GNUNET_break_op(0);
      return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
    case GNUNET_NO:
      /* xquery missmatch, can happen */
      return GNUNET_BLOCK_EVALUATION_RESULT_IRRELEVANT;
    default:
      break;
  }
  GNUNET_CRYPTO_hash (reply_block,
                      reply_block_size,
                      &chash);
  if (GNUNET_YES ==
      GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
                                          &chash))
    return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
  return GNUNET_BLOCK_EVALUATION_OK_MORE;
}


static enum GNUNET_BLOCK_EvaluationResult
evaluate_block_regex_accept (void *cls,
                             enum GNUNET_BLOCK_Type type,
                             struct GNUNET_BLOCK_Group *bg,
                             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)
{
  const struct RegexAcceptBlock *rba;
  struct GNUNET_HashCode chash;

  if (0 != xquery_size)
  {
    GNUNET_break_op (0);
    return GNUNET_BLOCK_EVALUATION_REQUEST_INVALID;
  }
  if (NULL == reply_block)
    return GNUNET_BLOCK_EVALUATION_REQUEST_VALID;
  if (sizeof (struct RegexAcceptBlock) != reply_block_size)
  {
    GNUNET_break_op(0);
    return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  }
  rba = reply_block;
  if (ntohl (rba->purpose.size) !=
      sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
      sizeof (struct GNUNET_TIME_AbsoluteNBO) +
      sizeof (struct GNUNET_HashCode))
  {
    GNUNET_break_op(0);
    return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  }
  if (0 == GNUNET_TIME_absolute_get_remaining (GNUNET_TIME_absolute_ntoh (rba->expiration_time)).rel_value_us)
  {
    /* technically invalid, but can happen without an error, so
       we're nice by reporting it as a 'duplicate' */
    return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
  }
  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify (GNUNET_SIGNATURE_PURPOSE_REGEX_ACCEPT,
                                &rba->purpose,
                                &rba->signature,
                                &rba->peer.public_key))
  {
    GNUNET_break_op(0);
    return GNUNET_BLOCK_EVALUATION_RESULT_INVALID;
  }
  GNUNET_CRYPTO_hash (reply_block,
                      reply_block_size,
                      &chash);
  if (GNUNET_YES ==
      GNUNET_BLOCK_GROUP_bf_test_and_set (bg,
                                          &chash))
    return GNUNET_BLOCK_EVALUATION_OK_DUPLICATE;
  return GNUNET_BLOCK_EVALUATION_OK_MORE;
}


static enum GNUNET_BLOCK_EvaluationResult
block_plugin_regex_evaluate (void *cls,
                             struct GNUNET_BLOCK_Context *ctx,
                             enum GNUNET_BLOCK_Type type,
                             struct GNUNET_BLOCK_Group *bg,
                             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)
{
  enum GNUNET_BLOCK_EvaluationResult result;

  switch (type)
  {
    case GNUNET_BLOCK_TYPE_REGEX:
      result = evaluate_block_regex (cls,
                                     type,
                                     bg,
                                     eo,
                                     query,
                                     xquery, xquery_size,
                                     reply_block, reply_block_size);
      break;
    case GNUNET_BLOCK_TYPE_REGEX_ACCEPT:
      result = evaluate_block_regex_accept (cls,
                                            type,
                                            bg,
                                            eo,
                                            query,
                                            xquery, xquery_size,
                                            reply_block, reply_block_size);
      break;

    default:
      result = GNUNET_BLOCK_EVALUATION_TYPE_NOT_SUPPORTED;
  }
  return result;
}


static int
block_plugin_regex_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_REGEX:
      if (GNUNET_OK !=
          REGEX_BLOCK_get_key (block, block_size,
                               key))
      {
        GNUNET_break_op (0);
        return GNUNET_NO;
      }
      return GNUNET_OK;
    case GNUNET_BLOCK_TYPE_REGEX_ACCEPT:
      if (sizeof (struct RegexAcceptBlock) != block_size)
      {
        GNUNET_break_op (0);
        return GNUNET_NO;
      }
      *key = ((struct RegexAcceptBlock *) block)->key;
      return GNUNET_OK;
    default:
      GNUNET_break (0);
      return GNUNET_SYSERR;
  }
}


void *
libgnunet_plugin_block_regex_init (void *cls)
{
  static enum GNUNET_BLOCK_Type types[] =
  {
    GNUNET_BLOCK_TYPE_REGEX,
    GNUNET_BLOCK_TYPE_REGEX_ACCEPT,
    GNUNET_BLOCK_TYPE_ANY       /* end of list */
  };
  struct GNUNET_BLOCK_PluginFunctions *api;

  api = GNUNET_new (struct GNUNET_BLOCK_PluginFunctions);
  api->evaluate = &block_plugin_regex_evaluate;
  api->get_key = &block_plugin_regex_get_key;
  api->create_group = &block_plugin_regex_create_group;
  api->types = types;
  return api;
}


void *
libgnunet_plugin_block_regex_done (void *cls)
{
  struct GNUNET_BLOCK_PluginFunctions *api = cls;

  GNUNET_free (api);
  return NULL;
}

/* end of plugin_block_regex.c */