--- /dev/null
+/* Copyright (C) 2006-2014 B.A.T.M.A.N. contributors:
+ *
+ * Simon Wunderlich, Marek Lindner
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License 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; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _NET_BATMAN_ADV_HASH_H_
+#define _NET_BATMAN_ADV_HASH_H_
+
+#include <linux/list.h>
+
+/* callback to a compare function. should compare 2 element datas for their
+ * keys, return 0 if same and not 0 if not same
+ */
+typedef int (*batadv_hashdata_compare_cb)(const struct hlist_node *,
+ const void *);
+
+/* the hashfunction, should return an index
+ * based on the key in the data of the first
+ * argument and the size the second
+ */
+typedef uint32_t (*batadv_hashdata_choose_cb)(const void *, uint32_t);
+typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *);
+
+struct batadv_hashtable {
+ struct hlist_head *table; /* the hashtable itself with the buckets */
+ spinlock_t *list_locks; /* spinlock for each hash list entry */
+ uint32_t size; /* size of hashtable */
+};
+
+/* allocates and clears the hash */
+struct batadv_hashtable *batadv_hash_new(uint32_t size);
+
+/* set class key for all locks */
+void batadv_hash_set_lock_class(struct batadv_hashtable *hash,
+ struct lock_class_key *key);
+
+/* free only the hashtable and the hash itself. */
+void batadv_hash_destroy(struct batadv_hashtable *hash);
+
+/* remove the hash structure. if hashdata_free_cb != NULL, this function will be
+ * called to remove the elements inside of the hash. if you don't remove the
+ * elements, memory might be leaked.
+ */
+static inline void batadv_hash_delete(struct batadv_hashtable *hash,
+ batadv_hashdata_free_cb free_cb,
+ void *arg)
+{
+ struct hlist_head *head;
+ struct hlist_node *node, *node_tmp;
+ spinlock_t *list_lock; /* spinlock to protect write access */
+ uint32_t i;
+
+ for (i = 0; i < hash->size; i++) {
+ head = &hash->table[i];
+ list_lock = &hash->list_locks[i];
+
+ spin_lock_bh(list_lock);
+ hlist_for_each_safe(node, node_tmp, head) {
+ hlist_del_rcu(node);
+
+ if (free_cb)
+ free_cb(node, arg);
+ }
+ spin_unlock_bh(list_lock);
+ }
+
+ batadv_hash_destroy(hash);
+}
+
+/**
+ * batadv_hash_bytes - hash some bytes and add them to the previous hash
+ * @hash: previous hash value
+ * @data: data to be hashed
+ * @size: number of bytes to be hashed
+ *
+ * Returns the new hash value.
+ */
+static inline uint32_t batadv_hash_bytes(uint32_t hash, const void *data,
+ uint32_t size)
+{
+ const unsigned char *key = data;
+ int i;
+
+ for (i = 0; i < size; i++) {
+ hash += key[i];
+ hash += (hash << 10);
+ hash ^= (hash >> 6);
+ }
+ return hash;
+}
+
+/**
+ * batadv_hash_add - adds data to the hashtable
+ * @hash: storage hash table
+ * @compare: callback to determine if 2 hash elements are identical
+ * @choose: callback calculating the hash index
+ * @data: data passed to the aforementioned callbacks as argument
+ * @data_node: to be added element
+ *
+ * Returns 0 on success, 1 if the element already is in the hash
+ * and -1 on error.
+ */
+static inline int batadv_hash_add(struct batadv_hashtable *hash,
+ batadv_hashdata_compare_cb compare,
+ batadv_hashdata_choose_cb choose,
+ const void *data,
+ struct hlist_node *data_node)
+{
+ uint32_t index;
+ int ret = -1;
+ struct hlist_head *head;
+ struct hlist_node *node;
+ spinlock_t *list_lock; /* spinlock to protect write access */
+
+ if (!hash)
+ goto out;
+
+ index = choose(data, hash->size);
+ head = &hash->table[index];
+ list_lock = &hash->list_locks[index];
+
+ spin_lock_bh(list_lock);
+
+ hlist_for_each(node, head) {
+ if (!compare(node, data))
+ continue;
+
+ ret = 1;
+ goto unlock;
+ }
+
+ /* no duplicate found in list, add new element */
+ hlist_add_head_rcu(data_node, head);
+
+ ret = 0;
+
+unlock:
+ spin_unlock_bh(list_lock);
+out:
+ return ret;
+}
+
+/* removes data from hash, if found. returns pointer do data on success, so you
+ * can remove the used structure yourself, or NULL on error . data could be the
+ * structure you use with just the key filled, we just need the key for
+ * comparing.
+ */
+static inline void *batadv_hash_remove(struct batadv_hashtable *hash,
+ batadv_hashdata_compare_cb compare,
+ batadv_hashdata_choose_cb choose,
+ void *data)
+{
+ uint32_t index;
+ struct hlist_node *node;
+ struct hlist_head *head;
+ void *data_save = NULL;
+
+ index = choose(data, hash->size);
+ head = &hash->table[index];
+
+ spin_lock_bh(&hash->list_locks[index]);
+ hlist_for_each(node, head) {
+ if (!compare(node, data))
+ continue;
+
+ data_save = node;
+ hlist_del_rcu(node);
+ break;
+ }
+ spin_unlock_bh(&hash->list_locks[index]);
+
+ return data_save;
+}
+
+#endif /* _NET_BATMAN_ADV_HASH_H_ */
Code Review / kvmfornfv.git / blobdiff