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