1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #include "opt_inet.h"
30 #include "opt_route.h"
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/mbuf.h>
37 #include <sys/kernel.h>
38
39 #include <net/route/nhop_utils.h>
40
41 #define BLOCK_ITEMS (8 * sizeof(u_long)) /* Number of items for ffsl() */
42
43 #define _BLOCKS_TO_SZ(_blocks) ((size_t)(_blocks) * sizeof(u_long))
44 #define _BLOCKS_TO_ITEMS(_blocks) ((uint32_t)(_blocks) * BLOCK_ITEMS)
45 #define _ITEMS_TO_BLOCKS(_items) ((_items) / BLOCK_ITEMS)
46
47 static void _bitmask_init_idx(void *index, uint32_t items);
48
49 void
bitmask_init(struct bitmask_head * bh,void * idx,uint32_t num_items)50 bitmask_init(struct bitmask_head *bh, void *idx, uint32_t num_items)
51 {
52
53 if (idx != NULL)
54 _bitmask_init_idx(idx, num_items);
55
56 memset(bh, 0, sizeof(struct bitmask_head));
57 bh->blocks = _ITEMS_TO_BLOCKS(num_items);
58 bh->idx = (u_long *)idx;
59 }
60
61 uint32_t
bitmask_get_resize_items(const struct bitmask_head * bh)62 bitmask_get_resize_items(const struct bitmask_head *bh)
63 {
64 if ((bh->items_count * 2 > _BLOCKS_TO_ITEMS(bh->blocks)) && bh->items_count < 65536)
65 return (_BLOCKS_TO_ITEMS(bh->blocks) * 2);
66
67 return (0);
68 }
69
70 int
bitmask_should_resize(const struct bitmask_head * bh)71 bitmask_should_resize(const struct bitmask_head *bh)
72 {
73
74 return (bitmask_get_resize_items(bh) != 0);
75 }
76
77 #if 0
78 uint32_t
79 _bitmask_get_blocks(uint32_t items)
80 {
81
82 return (items / BLOCK_ITEMS);
83 }
84 #endif
85
86 size_t
bitmask_get_size(uint32_t items)87 bitmask_get_size(uint32_t items)
88 {
89 #if _KERNEL
90 KASSERT((items % BLOCK_ITEMS) == 0,
91 ("bitmask size needs to power of 2 and greater or equal to %zu",
92 BLOCK_ITEMS));
93 #else
94 assert((items % BLOCK_ITEMS) == 0);
95 #endif
96
97 return (items / 8);
98 }
99
100 static void
_bitmask_init_idx(void * _idx,uint32_t items)101 _bitmask_init_idx(void *_idx, uint32_t items)
102 {
103 size_t size = bitmask_get_size(items);
104 u_long *idx = (u_long *)_idx;
105
106 /* Mark all as free */
107 memset(idx, 0xFF, size);
108 *idx &= ~(u_long)1; /* Always skip index 0 */
109 }
110
111 /*
112 * _try_merge api to allow shrinking?
113 */
114 int
bitmask_copy(const struct bitmask_head * bi,void * new_idx,uint32_t new_items)115 bitmask_copy(const struct bitmask_head *bi, void *new_idx, uint32_t new_items)
116 {
117 uint32_t new_blocks = _BLOCKS_TO_ITEMS(new_items);
118
119 _bitmask_init_idx(new_idx, new_items);
120
121 if (bi->blocks < new_blocks) {
122 /* extend current blocks */
123 if (bi->blocks > 0)
124 memcpy(new_idx, bi->idx, _BLOCKS_TO_SZ(bi->blocks));
125 return (0);
126 } else {
127 /* XXX: ensure all other blocks are non-zero */
128 for (int i = new_blocks; i < bi->blocks; i++) {
129 }
130
131 return (1);
132 }
133 }
134
135 void
bitmask_swap(struct bitmask_head * bh,void * new_idx,uint32_t new_items,void ** pidx)136 bitmask_swap(struct bitmask_head *bh, void *new_idx, uint32_t new_items, void **pidx)
137 {
138 void *old_ptr;
139
140 old_ptr = bh->idx;
141
142 bh->idx = (u_long *)new_idx;
143 bh->blocks = _ITEMS_TO_BLOCKS(new_items);
144
145 if (pidx != NULL)
146 *pidx = old_ptr;
147 }
148
149 /*
150 * Allocate new index in given instance and stores in in @pidx.
151 * Returns 0 on success.
152 */
153 int
bitmask_alloc_idx(struct bitmask_head * bi,uint16_t * pidx)154 bitmask_alloc_idx(struct bitmask_head *bi, uint16_t *pidx)
155 {
156 u_long *mask;
157 int i, off, v;
158
159 off = bi->free_off;
160 mask = &bi->idx[off];
161
162 for (i = off; i < bi->blocks; i++, mask++) {
163 if ((v = ffsl(*mask)) == 0)
164 continue;
165
166 /* Mark as busy */
167 *mask &= ~ ((u_long)1 << (v - 1));
168
169 bi->free_off = i;
170
171 v = BLOCK_ITEMS * i + v - 1;
172
173 *pidx = v;
174 bi->items_count++;
175 return (0);
176 }
177
178 return (1);
179 }
180
181 /*
182 * Removes index from given set.
183 * Returns 0 on success.
184 */
185 int
bitmask_free_idx(struct bitmask_head * bi,uint16_t idx)186 bitmask_free_idx(struct bitmask_head *bi, uint16_t idx)
187 {
188 u_long *mask;
189 int i, v;
190
191 if (idx == 0)
192 return (1);
193
194 i = idx / BLOCK_ITEMS;
195 v = idx % BLOCK_ITEMS;
196
197 if (i >= bi->blocks)
198 return (1);
199
200 mask = &bi->idx[i];
201
202 if ((*mask & ((u_long)1 << v)) != 0)
203 return (1);
204
205 /* Mark as free */
206 *mask |= (u_long)1 << v;
207 bi->items_count--;
208
209 /* Update free offset */
210 if (bi->free_off > i)
211 bi->free_off = i;
212
213 return (0);
214 }
215