blob: 377626250ac7129e1cf65d1768e0c2ee4643b59e [file] [log] [blame]
Kyle Swenson8d8f6542021-03-15 11:02:55 -06001/* Copyright (C) 2006-2015 B.A.T.M.A.N. contributors:
2 *
3 * Simon Wunderlich, Marek Lindner
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18#ifndef _NET_BATMAN_ADV_HASH_H_
19#define _NET_BATMAN_ADV_HASH_H_
20
21#include "main.h"
22
23#include <linux/compiler.h>
24#include <linux/list.h>
25#include <linux/rculist.h>
26#include <linux/spinlock.h>
27#include <linux/stddef.h>
28#include <linux/types.h>
29
30struct lock_class_key;
31
32/* callback to a compare function. should compare 2 element datas for their
33 * keys, return 0 if same and not 0 if not same
34 */
35typedef int (*batadv_hashdata_compare_cb)(const struct hlist_node *,
36 const void *);
37
38/* the hashfunction, should return an index
39 * based on the key in the data of the first
40 * argument and the size the second
41 */
42typedef u32 (*batadv_hashdata_choose_cb)(const void *, u32);
43typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *);
44
45struct batadv_hashtable {
46 struct hlist_head *table; /* the hashtable itself with the buckets */
47 spinlock_t *list_locks; /* spinlock for each hash list entry */
48 u32 size; /* size of hashtable */
49};
50
51/* allocates and clears the hash */
52struct batadv_hashtable *batadv_hash_new(u32 size);
53
54/* set class key for all locks */
55void batadv_hash_set_lock_class(struct batadv_hashtable *hash,
56 struct lock_class_key *key);
57
58/* free only the hashtable and the hash itself. */
59void batadv_hash_destroy(struct batadv_hashtable *hash);
60
61/* remove the hash structure. if hashdata_free_cb != NULL, this function will be
62 * called to remove the elements inside of the hash. if you don't remove the
63 * elements, memory might be leaked.
64 */
65static inline void batadv_hash_delete(struct batadv_hashtable *hash,
66 batadv_hashdata_free_cb free_cb,
67 void *arg)
68{
69 struct hlist_head *head;
70 struct hlist_node *node, *node_tmp;
71 spinlock_t *list_lock; /* spinlock to protect write access */
72 u32 i;
73
74 for (i = 0; i < hash->size; i++) {
75 head = &hash->table[i];
76 list_lock = &hash->list_locks[i];
77
78 spin_lock_bh(list_lock);
79 hlist_for_each_safe(node, node_tmp, head) {
80 hlist_del_rcu(node);
81
82 if (free_cb)
83 free_cb(node, arg);
84 }
85 spin_unlock_bh(list_lock);
86 }
87
88 batadv_hash_destroy(hash);
89}
90
91/**
92 * batadv_hash_add - adds data to the hashtable
93 * @hash: storage hash table
94 * @compare: callback to determine if 2 hash elements are identical
95 * @choose: callback calculating the hash index
96 * @data: data passed to the aforementioned callbacks as argument
97 * @data_node: to be added element
98 *
99 * Returns 0 on success, 1 if the element already is in the hash
100 * and -1 on error.
101 */
102static inline int batadv_hash_add(struct batadv_hashtable *hash,
103 batadv_hashdata_compare_cb compare,
104 batadv_hashdata_choose_cb choose,
105 const void *data,
106 struct hlist_node *data_node)
107{
108 u32 index;
109 int ret = -1;
110 struct hlist_head *head;
111 struct hlist_node *node;
112 spinlock_t *list_lock; /* spinlock to protect write access */
113
114 if (!hash)
115 goto out;
116
117 index = choose(data, hash->size);
118 head = &hash->table[index];
119 list_lock = &hash->list_locks[index];
120
121 spin_lock_bh(list_lock);
122
123 hlist_for_each(node, head) {
124 if (!compare(node, data))
125 continue;
126
127 ret = 1;
128 goto unlock;
129 }
130
131 /* no duplicate found in list, add new element */
132 hlist_add_head_rcu(data_node, head);
133
134 ret = 0;
135
136unlock:
137 spin_unlock_bh(list_lock);
138out:
139 return ret;
140}
141
142/* removes data from hash, if found. returns pointer do data on success, so you
143 * can remove the used structure yourself, or NULL on error . data could be the
144 * structure you use with just the key filled, we just need the key for
145 * comparing.
146 */
147static inline void *batadv_hash_remove(struct batadv_hashtable *hash,
148 batadv_hashdata_compare_cb compare,
149 batadv_hashdata_choose_cb choose,
150 void *data)
151{
152 u32 index;
153 struct hlist_node *node;
154 struct hlist_head *head;
155 void *data_save = NULL;
156
157 index = choose(data, hash->size);
158 head = &hash->table[index];
159
160 spin_lock_bh(&hash->list_locks[index]);
161 hlist_for_each(node, head) {
162 if (!compare(node, data))
163 continue;
164
165 data_save = node;
166 hlist_del_rcu(node);
167 break;
168 }
169 spin_unlock_bh(&hash->list_locks[index]);
170
171 return data_save;
172}
173
174#endif /* _NET_BATMAN_ADV_HASH_H_ */