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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) 2002-2010 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 "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
+{
+ 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);
+
+struct hash_iterator
+{
+ struct hash *hash;
+ int bucket_index;
+ struct hash_bucket *bucket;
+ struct hash_element *elem;
+ struct hash_element *last;
+ bool bucket_marked;
+ int bucket_index_start;
+ int bucket_index_end;
+};
+
+void hash_iterator_init_range (struct hash *hash,
+ struct hash_iterator *hi,
+ int start_bucket,
+ int end_bucket);
+
+void hash_iterator_init (struct hash *hash, struct hash_iterator *iter);
+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_lookup (struct hash *hash, const void *key)
+{
+ void *ret = NULL;
+ struct hash_element *he;
+ uint32_t hv = hash_value (hash, key);
+ struct hash_bucket *bucket = &hash->buckets[hv & hash->mask];
+
+ he = hash_lookup_fast (hash, bucket, key, hv);
+ if (he)
+ ret = he->value;
+
+ return ret;
+}
+
+/* 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];
+ ret = hash_remove_fast (hash, bucket, key, hv);
+ return ret;
+}
+
+#endif /* P2MP_SERVER */
+#endif /* LIST */