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ac79cbb9 | 1 | /* Copyright (C) 2006-2017 B.A.T.M.A.N. contributors: |
c6c8fea2 SE |
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 | |
ebf38fb7 | 15 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
c6c8fea2 SE |
16 | */ |
17 | ||
18 | #ifndef _NET_BATMAN_ADV_HASH_H_ | |
19 | #define _NET_BATMAN_ADV_HASH_H_ | |
20 | ||
1e2c2a4f SE |
21 | #include "main.h" |
22 | ||
23 | #include <linux/compiler.h> | |
c6c8fea2 | 24 | #include <linux/list.h> |
1e2c2a4f SE |
25 | #include <linux/rculist.h> |
26 | #include <linux/spinlock.h> | |
27 | #include <linux/stddef.h> | |
28 | #include <linux/types.h> | |
29 | ||
30 | struct lock_class_key; | |
c6c8fea2 | 31 | |
9cfc7bd6 | 32 | /* callback to a compare function. should compare 2 element datas for their |
62fe710f SE |
33 | * keys |
34 | * | |
4b426b10 | 35 | * Return: true if same and false if not same |
9cfc7bd6 | 36 | */ |
4b426b10 SE |
37 | typedef bool (*batadv_hashdata_compare_cb)(const struct hlist_node *, |
38 | const void *); | |
c6c8fea2 | 39 | |
62fe710f SE |
40 | /* the hashfunction |
41 | * | |
42 | * Return: an index based on the key in the data of the first argument and the | |
43 | * size the second | |
9cfc7bd6 | 44 | */ |
6b5e971a | 45 | typedef u32 (*batadv_hashdata_choose_cb)(const void *, u32); |
5bf74e9c | 46 | typedef void (*batadv_hashdata_free_cb)(struct hlist_node *, void *); |
c6c8fea2 | 47 | |
5bf74e9c | 48 | struct batadv_hashtable { |
fb778ea1 ML |
49 | struct hlist_head *table; /* the hashtable itself with the buckets */ |
50 | spinlock_t *list_locks; /* spinlock for each hash list entry */ | |
6b5e971a | 51 | u32 size; /* size of hashtable */ |
c6c8fea2 SE |
52 | }; |
53 | ||
54 | /* allocates and clears the hash */ | |
6b5e971a | 55 | struct batadv_hashtable *batadv_hash_new(u32 size); |
c6c8fea2 | 56 | |
5d52dad2 | 57 | /* set class key for all locks */ |
5bf74e9c | 58 | void batadv_hash_set_lock_class(struct batadv_hashtable *hash, |
5d52dad2 SE |
59 | struct lock_class_key *key); |
60 | ||
c6c8fea2 | 61 | /* free only the hashtable and the hash itself. */ |
5bf74e9c | 62 | void batadv_hash_destroy(struct batadv_hashtable *hash); |
c6c8fea2 | 63 | |
2c53040f BH |
64 | /** |
65 | * batadv_hash_add - adds data to the hashtable | |
1a1f37d9 AQ |
66 | * @hash: storage hash table |
67 | * @compare: callback to determine if 2 hash elements are identical | |
68 | * @choose: callback calculating the hash index | |
69 | * @data: data passed to the aforementioned callbacks as argument | |
70 | * @data_node: to be added element | |
71 | * | |
62fe710f | 72 | * Return: 0 on success, 1 if the element already is in the hash |
1a1f37d9 AQ |
73 | * and -1 on error. |
74 | */ | |
5bf74e9c SE |
75 | static inline int batadv_hash_add(struct batadv_hashtable *hash, |
76 | batadv_hashdata_compare_cb compare, | |
77 | batadv_hashdata_choose_cb choose, | |
c0a55929 SE |
78 | const void *data, |
79 | struct hlist_node *data_node) | |
c6c8fea2 | 80 | { |
6b5e971a | 81 | u32 index; |
c90681b8 | 82 | int ret = -1; |
c6c8fea2 | 83 | struct hlist_head *head; |
7aadf889 | 84 | struct hlist_node *node; |
fb778ea1 | 85 | spinlock_t *list_lock; /* spinlock to protect write access */ |
c6c8fea2 SE |
86 | |
87 | if (!hash) | |
1a1f37d9 | 88 | goto out; |
c6c8fea2 SE |
89 | |
90 | index = choose(data, hash->size); | |
91 | head = &hash->table[index]; | |
fb778ea1 | 92 | list_lock = &hash->list_locks[index]; |
c6c8fea2 | 93 | |
75c5a2e7 MS |
94 | spin_lock_bh(list_lock); |
95 | ||
96 | hlist_for_each(node, head) { | |
7aadf889 ML |
97 | if (!compare(node, data)) |
98 | continue; | |
99 | ||
1a1f37d9 | 100 | ret = 1; |
75c5a2e7 | 101 | goto unlock; |
c6c8fea2 SE |
102 | } |
103 | ||
104 | /* no duplicate found in list, add new element */ | |
7aadf889 | 105 | hlist_add_head_rcu(data_node, head); |
c6c8fea2 | 106 | |
1a1f37d9 | 107 | ret = 0; |
fb778ea1 | 108 | |
75c5a2e7 MS |
109 | unlock: |
110 | spin_unlock_bh(list_lock); | |
1a1f37d9 AQ |
111 | out: |
112 | return ret; | |
c6c8fea2 SE |
113 | } |
114 | ||
62fe710f SE |
115 | /* removes data from hash, if found. data could be the structure you use with |
116 | * just the key filled, we just need the key for comparing. | |
117 | * | |
118 | * Return: returns pointer do data on success, so you can remove the used | |
119 | * structure yourself, or NULL on error | |
9cfc7bd6 | 120 | */ |
5bf74e9c SE |
121 | static inline void *batadv_hash_remove(struct batadv_hashtable *hash, |
122 | batadv_hashdata_compare_cb compare, | |
123 | batadv_hashdata_choose_cb choose, | |
124 | void *data) | |
c6c8fea2 | 125 | { |
6b5e971a | 126 | u32 index; |
7aadf889 | 127 | struct hlist_node *node; |
c6c8fea2 | 128 | struct hlist_head *head; |
fb778ea1 | 129 | void *data_save = NULL; |
c6c8fea2 SE |
130 | |
131 | index = choose(data, hash->size); | |
132 | head = &hash->table[index]; | |
133 | ||
fb778ea1 | 134 | spin_lock_bh(&hash->list_locks[index]); |
7aadf889 ML |
135 | hlist_for_each(node, head) { |
136 | if (!compare(node, data)) | |
137 | continue; | |
138 | ||
139 | data_save = node; | |
140 | hlist_del_rcu(node); | |
141 | break; | |
c6c8fea2 | 142 | } |
fb778ea1 | 143 | spin_unlock_bh(&hash->list_locks[index]); |
c6c8fea2 | 144 | |
fb778ea1 | 145 | return data_save; |
c6c8fea2 SE |
146 | } |
147 | ||
c6c8fea2 | 148 | #endif /* _NET_BATMAN_ADV_HASH_H_ */ |