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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2009 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef LIST_H
#define LIST_H
/*
* This code is a fairly straightforward hash
* table implementation using Bob Jenkins'
* hash function.
*
* Hash tables are used in OpenVPN to keep track of
* client instances over various key spaces.
*/
#if P2MP_SERVER
/* define this to enable special list test mode */
/*#define LIST_TEST*/
#include "basic.h"
#include "thread.h"
#include "buffer.h"
#define hashsize(n) ((uint32_t)1<<(n))
#define hashmask(n) (hashsize(n)-1)
struct hash_element
{
void *value;
const void *key;
unsigned int hash_value;
struct hash_element *next;
};
struct hash_bucket
{
MUTEX_DEFINE (mutex);
struct hash_element *list;
};
struct hash
{
int n_buckets;
int n_elements;
int mask;
uint32_t iv;
uint32_t (*hash_function)(const void *key, uint32_t iv);
bool (*compare_function)(const void *key1, const void *key2); /* return true if equal */
struct hash_bucket *buckets;
};
struct hash *hash_init (const int n_buckets,
const uint32_t iv,
uint32_t (*hash_function)(const void *key, uint32_t iv),
bool (*compare_function)(const void *key1, const void *key2));
void hash_free (struct hash *hash);
bool hash_add (struct hash *hash, const void *key, void *value, bool replace);
struct hash_element *hash_lookup_fast (struct hash *hash,
struct hash_bucket *bucket,
const void *key,
uint32_t hv);
bool hash_remove_fast (struct hash *hash,
struct hash_bucket *bucket,
const void *key,
uint32_t hv);
void hash_remove_by_value (struct hash *hash, void *value, bool autolock);
struct hash_iterator
{
struct hash *hash;
int bucket_index;
struct hash_bucket *bucket;
struct hash_element *elem;
struct hash_element *last;
bool bucket_marked;
bool autolock;
int bucket_index_start;
int bucket_index_end;
};
void hash_iterator_init_range (struct hash *hash,
struct hash_iterator *hi,
bool autolock,
int start_bucket,
int end_bucket);
void hash_iterator_init (struct hash *hash, struct hash_iterator *iter, bool autolock);
struct hash_element *hash_iterator_next (struct hash_iterator *hi);
void hash_iterator_delete_element (struct hash_iterator *hi);
void hash_iterator_free (struct hash_iterator *hi);
uint32_t hash_func (const uint8_t *k, uint32_t length, uint32_t initval);
uint32_t void_ptr_hash_function (const void *key, uint32_t iv);
bool void_ptr_compare_function (const void *key1, const void *key2);
#ifdef LIST_TEST
void list_test (void);
#endif
static inline uint32_t
hash_value (const struct hash *hash, const void *key)
{
return (*hash->hash_function)(key, hash->iv);
}
static inline int
hash_n_elements (const struct hash *hash)
{
return hash->n_elements;
}
static inline int
hash_n_buckets (const struct hash *hash)
{
return hash->n_buckets;
}
static inline struct hash_bucket *
hash_bucket (struct hash *hash, uint32_t hv)
{
return &hash->buckets[hv & hash->mask];
}
static inline void
hash_bucket_lock (struct hash_bucket *bucket)
{
mutex_lock (&bucket->mutex);
}
static inline void
hash_bucket_unlock (struct hash_bucket *bucket)
{
mutex_unlock (&bucket->mutex);
}
static inline void *
hash_lookup_lock (struct hash *hash, const void *key, uint32_t hv)
{
void *ret = NULL;
struct hash_element *he;
struct hash_bucket *bucket = &hash->buckets[hv & hash->mask];
mutex_lock (&bucket->mutex);
he = hash_lookup_fast (hash, bucket, key, hv);
if (he)
ret = he->value;
mutex_unlock (&bucket->mutex);
return ret;
}
static inline void *
hash_lookup (struct hash *hash, const void *key)
{
return hash_lookup_lock (hash, key, hash_value (hash, key));
}
/* NOTE: assumes that key is not a duplicate */
static inline void
hash_add_fast (struct hash *hash,
struct hash_bucket *bucket,
const void *key,
uint32_t hv,
void *value)
{
struct hash_element *he;
ALLOC_OBJ (he, struct hash_element);
he->value = value;
he->key = key;
he->hash_value = hv;
he->next = bucket->list;
bucket->list = he;
++hash->n_elements;
}
static inline bool
hash_remove (struct hash *hash, const void *key)
{
uint32_t hv;
struct hash_bucket *bucket;
bool ret;
hv = hash_value (hash, key);
bucket = &hash->buckets[hv & hash->mask];
mutex_lock (&bucket->mutex);
ret = hash_remove_fast (hash, bucket, key, hv);
mutex_unlock (&bucket->mutex);
return ret;
}
#endif /* P2MP_SERVER */
#endif /* LIST */
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