gnunet-service-testbed_cache.c

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/*
   This file is part of GNUnet.
   Copyright (C) 2008--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-service-testbed.h"
 
#ifdef LOG
#undef LOG
#endif
#define LOG(kind, ...)                                   \
  GNUNET_log_from (kind, "testbed-cache", __VA_ARGS__)
 
 
struct CacheEntry
{
  struct CacheEntry *next;
 
  struct CacheEntry *prev;
 
  struct GNUNET_MessageHeader *hello;
 
  unsigned int peer_id;
};
 
 
static struct GNUNET_CONTAINER_MultiHashMap32 *cache;
 
static struct CacheEntry *cache_head;
 
static struct CacheEntry *cache_tail;
 
static unsigned int cache_size;
 
 
static struct CacheEntry *
cache_lookup (unsigned int peer_id)
{
  struct CacheEntry *entry;
 
  GNUNET_assert (NULL != cache);
  entry = GNUNET_CONTAINER_multihashmap32_get (cache, peer_id);
  if (NULL == entry)
    return NULL;
  GNUNET_CONTAINER_DLL_remove (cache_head, cache_tail, entry);
  GNUNET_CONTAINER_DLL_insert_tail (cache_head, cache_tail, entry);
  return entry;
}
 
 
static void
free_entry (struct CacheEntry *entry)
{
  GNUNET_CONTAINER_DLL_remove (cache_head, cache_tail, entry);
  GNUNET_free (entry->hello);
  GNUNET_free (entry);
}
 
 
static struct CacheEntry *
add_entry (unsigned int peer_id)
{
  struct CacheEntry *entry;
 
  GNUNET_assert (NULL != cache);
  if (cache_size == GNUNET_CONTAINER_multihashmap32_size (cache))
  {
    /* remove the LRU head */
    entry = cache_head;
    GNUNET_assert (GNUNET_OK ==
                   GNUNET_CONTAINER_multihashmap32_remove (cache, (uint32_t)
                                                           entry->peer_id,
                                                           entry));
    free_entry (entry);
  }
  entry = GNUNET_new (struct CacheEntry);
  entry->peer_id = peer_id;
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_CONTAINER_multihashmap32_put (cache,
                                                      (uint32_t) peer_id,
                                                      entry,
                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST));
  GNUNET_CONTAINER_DLL_insert_tail (cache_head, cache_tail, entry);
  return entry;
}
 
 
static int
cache_clear_iterator (void *cls, uint32_t key, void *value)
{
  struct CacheEntry *entry = value;
 
  GNUNET_assert (NULL != entry);
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CONTAINER_multihashmap32_remove (cache, key, value));
  free_entry (entry);
  return GNUNET_YES;
}
 
 
void
GST_cache_clear ()
{
  if (NULL != cache)
  {
    GNUNET_CONTAINER_multihashmap32_iterate (cache, &cache_clear_iterator,
                                             NULL);
    GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap32_size (cache));
    GNUNET_CONTAINER_multihashmap32_destroy (cache);
    cache = NULL;
  }
  cache_size = 0;
  cache_head = NULL;
  cache_tail = NULL;
}
 
 
void
GST_cache_init (unsigned int size)
{
  if (0 == size)
    return;
  cache_size = size;
  cache = GNUNET_CONTAINER_multihashmap32_create (cache_size);
}
 
 
const struct GNUNET_MessageHeader *
GST_cache_lookup_hello (const unsigned int peer_id)
{
  struct CacheEntry *entry;
 
  LOG_DEBUG ("Looking up HELLO for peer %u\n", peer_id);
  if (NULL == cache)
  {
    LOG_DEBUG ("Caching disabled\n");
    return NULL;
  }
  entry = cache_lookup (peer_id);
  if (NULL == entry)
    return NULL;
  if (NULL != entry->hello)
    LOG_DEBUG ("HELLO found for peer %u\n", peer_id);
  return entry->hello;
}
 
 
void
GST_cache_add_hello (const unsigned int peer_id,
                     const struct GNUNET_MessageHeader *hello)
{
  struct CacheEntry *entry;
 
  if (NULL == cache)
    return;
  entry = cache_lookup (peer_id);
  if (NULL == entry)
    entry = add_entry (peer_id);
  GNUNET_free (entry->hello);
  entry->hello = GNUNET_copy_message (hello);
}
 
 
/* end of gnunet-service-testbed_hc.c */