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