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 #ifndef _SS_EBITMAP_H_
16 #define _SS_EBITMAP_H_
17 
18 #include <net/netlabel.h>
19 
20 #ifdef CONFIG_64BIT
21 #define	EBITMAP_NODE_SIZE	64
22 #else
23 #define	EBITMAP_NODE_SIZE	32
24 #endif
25 
26 #define EBITMAP_UNIT_NUMS	((EBITMAP_NODE_SIZE-sizeof(void *)-sizeof(u32))\
27 					/ sizeof(unsigned long))
28 #define EBITMAP_UNIT_SIZE	BITS_PER_LONG
29 #define EBITMAP_SIZE		(EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
30 #define EBITMAP_BIT		1ULL
31 #define EBITMAP_SHIFT_UNIT_SIZE(x)					\
32 	(((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
33 
34 struct ebitmap_node {
35 	struct ebitmap_node *next;
36 	unsigned long maps[EBITMAP_UNIT_NUMS];
37 	u32 startbit;
38 };
39 
40 struct ebitmap {
41 	struct ebitmap_node *node;	/* first node in the bitmap */
42 	u32 highbit;	/* highest position in the total bitmap */
43 };
44 
45 #define ebitmap_length(e) ((e)->highbit)
46 
ebitmap_start_positive(const struct ebitmap * e,struct ebitmap_node ** n)47 static inline unsigned int ebitmap_start_positive(const struct ebitmap *e,
48 						  struct ebitmap_node **n)
49 {
50 	unsigned int ofs;
51 
52 	for (*n = e->node; *n; *n = (*n)->next) {
53 		ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
54 		if (ofs < EBITMAP_SIZE)
55 			return (*n)->startbit + ofs;
56 	}
57 	return ebitmap_length(e);
58 }
59 
ebitmap_init(struct ebitmap * e)60 static inline void ebitmap_init(struct ebitmap *e)
61 {
62 	memset(e, 0, sizeof(*e));
63 }
64 
ebitmap_next_positive(const struct ebitmap * e,struct ebitmap_node ** n,unsigned int bit)65 static inline unsigned int ebitmap_next_positive(const struct ebitmap *e,
66 						 struct ebitmap_node **n,
67 						 unsigned int bit)
68 {
69 	unsigned int ofs;
70 
71 	ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
72 	if (ofs < EBITMAP_SIZE)
73 		return ofs + (*n)->startbit;
74 
75 	for (*n = (*n)->next; *n; *n = (*n)->next) {
76 		ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
77 		if (ofs < EBITMAP_SIZE)
78 			return ofs + (*n)->startbit;
79 	}
80 	return ebitmap_length(e);
81 }
82 
83 #define EBITMAP_NODE_INDEX(node, bit)	\
84 	(((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
85 #define EBITMAP_NODE_OFFSET(node, bit)	\
86 	(((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
87 
ebitmap_node_get_bit(const struct ebitmap_node * n,unsigned int bit)88 static inline int ebitmap_node_get_bit(const struct ebitmap_node *n,
89 				       unsigned int bit)
90 {
91 	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
92 	unsigned int 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 
ebitmap_node_set_bit(struct ebitmap_node * n,unsigned int bit)100 static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
101 					unsigned int bit)
102 {
103 	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
104 	unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
105 
106 	BUG_ON(index >= EBITMAP_UNIT_NUMS);
107 	n->maps[index] |= (EBITMAP_BIT << ofs);
108 }
109 
ebitmap_node_clr_bit(struct ebitmap_node * n,unsigned int bit)110 static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
111 					unsigned int bit)
112 {
113 	unsigned int index = EBITMAP_NODE_INDEX(n, bit);
114 	unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
115 
116 	BUG_ON(index >= EBITMAP_UNIT_NUMS);
117 	n->maps[index] &= ~(EBITMAP_BIT << ofs);
118 }
119 
120 #define ebitmap_for_each_positive_bit(e, n, bit)	\
121 	for ((bit) = ebitmap_start_positive(e, &(n));	\
122 	     (bit) < ebitmap_length(e);			\
123 	     (bit) = ebitmap_next_positive(e, &(n), bit))	\
124 
125 int ebitmap_cmp(const struct ebitmap *e1, const struct ebitmap *e2);
126 int ebitmap_cpy(struct ebitmap *dst, const struct ebitmap *src);
127 int ebitmap_and(struct ebitmap *dst, const struct ebitmap *e1, const struct ebitmap *e2);
128 int ebitmap_contains(const struct ebitmap *e1, const struct ebitmap *e2, u32 last_e2bit);
129 int ebitmap_get_bit(const struct ebitmap *e, unsigned long bit);
130 int ebitmap_set_bit(struct ebitmap *e, unsigned long 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
ebitmap_netlbl_export(struct ebitmap * ebmap,struct netlbl_lsm_catmap ** catmap)142 static inline int ebitmap_netlbl_export(struct ebitmap *ebmap,
143 					struct netlbl_lsm_catmap **catmap)
144 {
145 	return -ENOMEM;
146 }
ebitmap_netlbl_import(struct ebitmap * ebmap,struct netlbl_lsm_catmap * catmap)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