1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2020 Alexander V. Chernikov 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 #include "opt_inet.h" 31 #include "opt_route.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/lock.h> 36 #include <sys/malloc.h> 37 #include <sys/mbuf.h> 38 #include <sys/kernel.h> 39 40 #include <net/route/nhop_utils.h> 41 42 #define BLOCK_ITEMS (8 * sizeof(u_long)) /* Number of items for ffsl() */ 43 44 #define _BLOCKS_TO_SZ(_blocks) ((size_t)(_blocks) * sizeof(u_long)) 45 #define _BLOCKS_TO_ITEMS(_blocks) ((uint32_t)(_blocks) * BLOCK_ITEMS) 46 #define _ITEMS_TO_BLOCKS(_items) ((_items) / BLOCK_ITEMS) 47 48 static void _bitmask_init_idx(void *index, uint32_t items); 49 50 void 51 bitmask_init(struct bitmask_head *bh, void *idx, uint32_t num_items) 52 { 53 54 if (idx != NULL) 55 _bitmask_init_idx(idx, num_items); 56 57 memset(bh, 0, sizeof(struct bitmask_head)); 58 bh->blocks = _ITEMS_TO_BLOCKS(num_items); 59 bh->idx = (u_long *)idx; 60 } 61 62 uint32_t 63 bitmask_get_resize_items(const struct bitmask_head *bh) 64 { 65 if ((bh->items_count * 2 > _BLOCKS_TO_ITEMS(bh->blocks)) && bh->items_count < 65536) 66 return (_BLOCKS_TO_ITEMS(bh->blocks) * 2); 67 68 return (0); 69 } 70 71 int 72 bitmask_should_resize(const struct bitmask_head *bh) 73 { 74 75 return (bitmask_get_resize_items(bh) != 0); 76 } 77 78 #if 0 79 uint32_t 80 _bitmask_get_blocks(uint32_t items) 81 { 82 83 return (items / BLOCK_ITEMS); 84 } 85 #endif 86 87 size_t 88 bitmask_get_size(uint32_t items) 89 { 90 #if _KERNEL 91 KASSERT((items % BLOCK_ITEMS) == 0, 92 ("bitmask size needs to power of 2 and greater or equal to %zu", 93 BLOCK_ITEMS)); 94 #else 95 assert((items % BLOCK_ITEMS) == 0); 96 #endif 97 98 return (items / 8); 99 } 100 101 static void 102 _bitmask_init_idx(void *_idx, uint32_t items) 103 { 104 size_t size = bitmask_get_size(items); 105 u_long *idx = (u_long *)_idx; 106 107 /* Mark all as free */ 108 memset(idx, 0xFF, size); 109 *idx &= ~(u_long)1; /* Always skip index 0 */ 110 } 111 112 /* 113 * _try_merge api to allow shrinking? 114 */ 115 int 116 bitmask_copy(const struct bitmask_head *bi, void *new_idx, uint32_t new_items) 117 { 118 uint32_t new_blocks = _BLOCKS_TO_ITEMS(new_items); 119 120 _bitmask_init_idx(new_idx, new_items); 121 122 if (bi->blocks < new_blocks) { 123 /* extend current blocks */ 124 if (bi->blocks > 0) 125 memcpy(new_idx, bi->idx, _BLOCKS_TO_SZ(bi->blocks)); 126 return (0); 127 } else { 128 /* XXX: ensure all other blocks are non-zero */ 129 for (int i = new_blocks; i < bi->blocks; i++) { 130 } 131 132 return (1); 133 } 134 } 135 136 void 137 bitmask_swap(struct bitmask_head *bh, void *new_idx, uint32_t new_items, void **pidx) 138 { 139 void *old_ptr; 140 141 old_ptr = bh->idx; 142 143 bh->idx = (u_long *)new_idx; 144 bh->blocks = _ITEMS_TO_BLOCKS(new_items); 145 146 if (pidx != NULL) 147 *pidx = old_ptr; 148 } 149 150 /* 151 * Allocate new index in given instance and stores in in @pidx. 152 * Returns 0 on success. 153 */ 154 int 155 bitmask_alloc_idx(struct bitmask_head *bi, uint16_t *pidx) 156 { 157 u_long *mask; 158 int i, off, v; 159 160 off = bi->free_off; 161 mask = &bi->idx[off]; 162 163 for (i = off; i < bi->blocks; i++, mask++) { 164 if ((v = ffsl(*mask)) == 0) 165 continue; 166 167 /* Mark as busy */ 168 *mask &= ~ ((u_long)1 << (v - 1)); 169 170 bi->free_off = i; 171 172 v = BLOCK_ITEMS * i + v - 1; 173 174 *pidx = v; 175 bi->items_count++; 176 return (0); 177 } 178 179 return (1); 180 } 181 182 /* 183 * Removes index from given set. 184 * Returns 0 on success. 185 */ 186 int 187 bitmask_free_idx(struct bitmask_head *bi, uint16_t idx) 188 { 189 u_long *mask; 190 int i, v; 191 192 if (idx == 0) 193 return (1); 194 195 i = idx / BLOCK_ITEMS; 196 v = idx % BLOCK_ITEMS; 197 198 if (i >= bi->blocks) 199 return (1); 200 201 mask = &bi->idx[i]; 202 203 if ((*mask & ((u_long)1 << v)) != 0) 204 return (1); 205 206 /* Mark as free */ 207 *mask |= (u_long)1 << v; 208 bi->items_count--; 209 210 /* Update free offset */ 211 if (bi->free_off > i) 212 bi->free_off = i; 213 214 return (0); 215 } 216