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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, <sds@tycho.nsa.gov>
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(struct ebitmap * e,struct ebitmap_node ** n)47  static inline unsigned int ebitmap_start_positive(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(struct ebitmap * e,struct ebitmap_node ** n,unsigned int bit)65  static inline unsigned int ebitmap_next_positive(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(struct ebitmap_node * n,unsigned int bit)88  static inline int ebitmap_node_get_bit(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(struct ebitmap *e1, struct ebitmap *e2);
126  int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
127  int ebitmap_and(struct ebitmap *dst, struct ebitmap *e1, struct ebitmap *e2);
128  int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2, u32 last_e2bit);
129  int ebitmap_get_bit(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(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