1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
/*
* Copyright (C) 2006-2012 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
*
*/
#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 (*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 (*hashdata_choose_cb)(const void *, uint32_t);
typedef void (*hashdata_free_cb)(struct hlist_node *, void *);
struct hashtable_t {
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 hashtable_t *hash_new(uint32_t size);
/* free only the hashtable and the hash itself. */
void hash_destroy(struct hashtable_t *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 hash_delete(struct hashtable_t *hash,
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);
}
hash_destroy(hash);
}
/**
* 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 hash_add(struct hashtable_t *hash,
hashdata_compare_cb compare,
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];
rcu_read_lock();
__hlist_for_each_rcu(node, head) {
if (!compare(node, data))
continue;
ret = 1;
goto err_unlock;
}
rcu_read_unlock();
/* no duplicate found in list, add new element */
spin_lock_bh(list_lock);
hlist_add_head_rcu(data_node, head);
spin_unlock_bh(list_lock);
ret = 0;
goto out;
err_unlock:
rcu_read_unlock();
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 *hash_remove(struct hashtable_t *hash,
hashdata_compare_cb compare,
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_ */
|
