1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * An extensible bitmap is a bitmap that supports an
4 * arbitrary number of bits. Extensible bitmaps are
5 * used to represent sets of values, such as types,
6 * roles, categories, and classes.
7 *
8 * Each extensible bitmap is implemented as a linked
9 * list of bitmap nodes, where each bitmap node has
10 * an explicitly specified starting bit position within
11 * the total bitmap.
12 *
13 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
14 */
15
16 #ifndef _SS_EBITMAP_H_
17 #define _SS_EBITMAP_H_
18
19 #include <net/netlabel.h>
20
21 #ifdef CONFIG_64BIT
22 #define EBITMAP_NODE_SIZE 64
23 #else
24 #define EBITMAP_NODE_SIZE 32
25 #endif
26
27 #define EBITMAP_UNIT_NUMS \
28 ((EBITMAP_NODE_SIZE - sizeof(void *) - sizeof(u32)) / \
29 sizeof(unsigned long))
30 #define EBITMAP_UNIT_SIZE BITS_PER_LONG
31 #define EBITMAP_SIZE (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
32 #define EBITMAP_BIT 1UL
33 #define EBITMAP_SHIFT_UNIT_SIZE(x) \
34 (((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
35
36 struct ebitmap_node {
37 struct ebitmap_node *next;
38 unsigned long maps[EBITMAP_UNIT_NUMS];
39 u32 startbit;
40 };
41
42 struct ebitmap {
43 struct ebitmap_node *node; /* first node in the bitmap */
44 u32 highbit; /* highest position in the total bitmap */
45 };
46
47 #define ebitmap_length(e) ((e)->highbit)
48
49 static inline u32 ebitmap_start_positive(const struct ebitmap *e,
50 struct ebitmap_node **n)
51 {
52 u32 ofs;
53
54 for (*n = e->node; *n; *n = (*n)->next) {
55 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
56 if (ofs < EBITMAP_SIZE)
57 return (*n)->startbit + ofs;
58 }
59 return ebitmap_length(e);
60 }
61
62 static inline void ebitmap_init(struct ebitmap *e)
63 {
64 memset(e, 0, sizeof(*e));
65 }
66
67 static inline u32 ebitmap_next_positive(const struct ebitmap *e,
68 struct ebitmap_node **n, u32 bit)
69 {
70 u32 ofs;
71
72 ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
73 if (ofs < EBITMAP_SIZE)
74 return ofs + (*n)->startbit;
75
76 for (*n = (*n)->next; *n; *n = (*n)->next) {
77 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
78 if (ofs < EBITMAP_SIZE)
79 return ofs + (*n)->startbit;
80 }
81 return ebitmap_length(e);
82 }
83
84 #define EBITMAP_NODE_INDEX(node, bit) \
85 (((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
86 #define EBITMAP_NODE_OFFSET(node, bit) \
87 (((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
88
89 static inline int ebitmap_node_get_bit(const struct ebitmap_node *n, u32 bit)
90 {
91 u32 index = EBITMAP_NODE_INDEX(n, bit);
92 u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
93
94 BUG_ON(index >= EBITMAP_UNIT_NUMS);
95 if ((n->maps[index] & (EBITMAP_BIT << ofs)))
96 return 1;
97 return 0;
98 }
99
100 static inline void ebitmap_node_set_bit(struct ebitmap_node *n, u32 bit)
101 {
102 u32 index = EBITMAP_NODE_INDEX(n, bit);
103 u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
104
105 BUG_ON(index >= EBITMAP_UNIT_NUMS);
106 n->maps[index] |= (EBITMAP_BIT << ofs);
107 }
108
109 static inline void ebitmap_node_clr_bit(struct ebitmap_node *n, u32 bit)
110 {
111 u32 index = EBITMAP_NODE_INDEX(n, bit);
112 u32 ofs = EBITMAP_NODE_OFFSET(n, bit);
113
114 BUG_ON(index >= EBITMAP_UNIT_NUMS);
115 n->maps[index] &= ~(EBITMAP_BIT << ofs);
116 }
117
118 #define ebitmap_for_each_positive_bit(e, n, bit) \
119 for ((bit) = ebitmap_start_positive(e, &(n)); \
120 (bit) < ebitmap_length(e); \
121 (bit) = ebitmap_next_positive(e, &(n), bit))
122
123 int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2);
124 int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src);
125 int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1,
126 const struct ebitmap *e2);
127 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2,
128 u32 last_e2bit);
129 int ebitmap_get_bit(const struct ebitmap *e, u32 bit);
130 int ebitmap_set_bit(struct ebitmap *e, u32 bit, int value);
131 void ebitmap_destroy(struct ebitmap *e);
132 int ebitmap_read(struct ebitmap *e, void *fp);
133 int ebitmap_write(const struct ebitmap *e, void *fp);
134 u32 ebitmap_hash(const struct ebitmap *e, u32 hash);
135
136 #ifdef CONFIG_NETLABEL
137 int ebitmap_netlbl_export(struct ebitmap *ebmap,
138 struct netlbl_lsm_catmap **catmap);
139 int ebitmap_netlbl_import(struct ebitmap *ebmap,
140 struct netlbl_lsm_catmap *catmap);
141 #else
142 static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
143 struct netlbl_lsm_catmap **catmap)
144 {
145 return -ENOMEM;
146 }
147 static inline int ebitmap_netlbl_import(struct ebitmap *ebmap,
148 struct netlbl_lsm_catmap *catmap)
149 {
150 return -ENOMEM;
151 }
152 #endif
153
154 #endif /* _SS_EBITMAP_H_ */
155
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