gnunet-service-rps_sampler_elem.c

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/*
     This file is part of GNUnet.
     Copyright (C)

     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_util_lib.h"

#include "gnunet-service-rps_sampler_elem.h"

#include <inttypes.h>

#include "rps-test_util.h"

#define LOG(kind, ...) GNUNET_log_from(kind, "rps-sampler_elem", __VA_ARGS__)


/***********************************************************************
* WARNING: This section needs to be reviewed regarding the use of
* functions providing (pseudo)randomness!
***********************************************************************/


void
RPS_sampler_elem_reinit(struct RPS_SamplerElement *sampler_elem)
{
  sampler_elem->is_empty = EMPTY;

  // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_STRONG,
                             &(sampler_elem->auth_key.key),
                             GNUNET_CRYPTO_HASH_LENGTH);

  sampler_elem->last_client_request = GNUNET_TIME_UNIT_FOREVER_ABS;

  sampler_elem->birth = GNUNET_TIME_absolute_get();
  sampler_elem->num_peers = 0;
  sampler_elem->num_change = 0;
}


struct RPS_SamplerElement *
RPS_sampler_elem_create(void)
{
  struct RPS_SamplerElement *s;

  s = GNUNET_new(struct RPS_SamplerElement);

  RPS_sampler_elem_reinit(s);

  return s;
}


void
RPS_sampler_elem_destroy(struct RPS_SamplerElement *sampler_elem)
{
  GNUNET_free(sampler_elem);
}


void
RPS_sampler_elem_next(struct RPS_SamplerElement *sampler_elem,
                      const struct GNUNET_PeerIdentity *new_ID)
{
  struct GNUNET_HashCode other_hash;

  sampler_elem->num_peers++;

  if (0 == GNUNET_memcmp(new_ID, &(sampler_elem->peer_id)))
    {
      LOG(GNUNET_ERROR_TYPE_DEBUG, "Have already PeerID %s\n",
          GNUNET_i2s(&(sampler_elem->peer_id)));
    }
  else
    {
      GNUNET_CRYPTO_hmac(&sampler_elem->auth_key,
                         new_ID,
                         sizeof(struct GNUNET_PeerIdentity),
                         &other_hash);

      if (EMPTY == sampler_elem->is_empty)
        {
          LOG(GNUNET_ERROR_TYPE_DEBUG,
              "Got PeerID %s; Simply accepting (was empty previously).\n",
              GNUNET_i2s(new_ID));
          sampler_elem->peer_id = *new_ID;
          sampler_elem->peer_id_hash = other_hash;

          sampler_elem->num_change++;
        }
      else if (0 > GNUNET_CRYPTO_hash_cmp(&other_hash, &sampler_elem->peer_id_hash))
        {
          LOG(GNUNET_ERROR_TYPE_DEBUG, "Discarding old PeerID %s\n",
              GNUNET_i2s(&sampler_elem->peer_id));
          sampler_elem->peer_id = *new_ID;
          sampler_elem->peer_id_hash = other_hash;

          sampler_elem->num_change++;
        }
      else
        {
          LOG(GNUNET_ERROR_TYPE_DEBUG, "Keeping old PeerID %s\n",
              GNUNET_i2s(&sampler_elem->peer_id));
        }
    }
  sampler_elem->is_empty = NOT_EMPTY;
}

void
RPS_sampler_elem_set(struct RPS_SamplerElement *sampler_elem,
                     struct GNUNET_CRYPTO_AuthKey auth_key)
{
  sampler_elem->auth_key = auth_key;
}

/* end of gnunet-service-rps.c */