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 */