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28fbcfa0 AS |
1 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, but | |
8 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
10 | * General Public License for more details. | |
11 | */ | |
12 | #include <linux/bpf.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/vmalloc.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/mm.h> | |
04fd61ab | 17 | #include <linux/filter.h> |
28fbcfa0 AS |
18 | |
19 | /* Called from syscall */ | |
20 | static struct bpf_map *array_map_alloc(union bpf_attr *attr) | |
21 | { | |
22 | struct bpf_array *array; | |
daaf427c | 23 | u32 elem_size, array_size; |
28fbcfa0 AS |
24 | |
25 | /* check sanity of attributes */ | |
26 | if (attr->max_entries == 0 || attr->key_size != 4 || | |
27 | attr->value_size == 0) | |
28 | return ERR_PTR(-EINVAL); | |
29 | ||
30 | elem_size = round_up(attr->value_size, 8); | |
31 | ||
daaf427c AS |
32 | /* check round_up into zero and u32 overflow */ |
33 | if (elem_size == 0 || | |
34 | attr->max_entries > (U32_MAX - sizeof(*array)) / elem_size) | |
35 | return ERR_PTR(-ENOMEM); | |
36 | ||
37 | array_size = sizeof(*array) + attr->max_entries * elem_size; | |
38 | ||
28fbcfa0 | 39 | /* allocate all map elements and zero-initialize them */ |
daaf427c | 40 | array = kzalloc(array_size, GFP_USER | __GFP_NOWARN); |
28fbcfa0 | 41 | if (!array) { |
daaf427c | 42 | array = vzalloc(array_size); |
28fbcfa0 AS |
43 | if (!array) |
44 | return ERR_PTR(-ENOMEM); | |
45 | } | |
46 | ||
47 | /* copy mandatory map attributes */ | |
48 | array->map.key_size = attr->key_size; | |
49 | array->map.value_size = attr->value_size; | |
50 | array->map.max_entries = attr->max_entries; | |
51 | ||
52 | array->elem_size = elem_size; | |
53 | ||
54 | return &array->map; | |
28fbcfa0 AS |
55 | } |
56 | ||
57 | /* Called from syscall or from eBPF program */ | |
58 | static void *array_map_lookup_elem(struct bpf_map *map, void *key) | |
59 | { | |
60 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
61 | u32 index = *(u32 *)key; | |
62 | ||
63 | if (index >= array->map.max_entries) | |
64 | return NULL; | |
65 | ||
66 | return array->value + array->elem_size * index; | |
67 | } | |
68 | ||
69 | /* Called from syscall */ | |
70 | static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key) | |
71 | { | |
72 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
73 | u32 index = *(u32 *)key; | |
74 | u32 *next = (u32 *)next_key; | |
75 | ||
76 | if (index >= array->map.max_entries) { | |
77 | *next = 0; | |
78 | return 0; | |
79 | } | |
80 | ||
81 | if (index == array->map.max_entries - 1) | |
82 | return -ENOENT; | |
83 | ||
84 | *next = index + 1; | |
85 | return 0; | |
86 | } | |
87 | ||
88 | /* Called from syscall or from eBPF program */ | |
89 | static int array_map_update_elem(struct bpf_map *map, void *key, void *value, | |
90 | u64 map_flags) | |
91 | { | |
92 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
93 | u32 index = *(u32 *)key; | |
94 | ||
95 | if (map_flags > BPF_EXIST) | |
96 | /* unknown flags */ | |
97 | return -EINVAL; | |
98 | ||
99 | if (index >= array->map.max_entries) | |
100 | /* all elements were pre-allocated, cannot insert a new one */ | |
101 | return -E2BIG; | |
102 | ||
103 | if (map_flags == BPF_NOEXIST) | |
daaf427c | 104 | /* all elements already exist */ |
28fbcfa0 AS |
105 | return -EEXIST; |
106 | ||
107 | memcpy(array->value + array->elem_size * index, value, array->elem_size); | |
108 | return 0; | |
109 | } | |
110 | ||
111 | /* Called from syscall or from eBPF program */ | |
112 | static int array_map_delete_elem(struct bpf_map *map, void *key) | |
113 | { | |
114 | return -EINVAL; | |
115 | } | |
116 | ||
117 | /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ | |
118 | static void array_map_free(struct bpf_map *map) | |
119 | { | |
120 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
121 | ||
122 | /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, | |
123 | * so the programs (can be more than one that used this map) were | |
124 | * disconnected from events. Wait for outstanding programs to complete | |
125 | * and free the array | |
126 | */ | |
127 | synchronize_rcu(); | |
128 | ||
129 | kvfree(array); | |
130 | } | |
131 | ||
a2c83fff | 132 | static const struct bpf_map_ops array_ops = { |
28fbcfa0 AS |
133 | .map_alloc = array_map_alloc, |
134 | .map_free = array_map_free, | |
135 | .map_get_next_key = array_map_get_next_key, | |
136 | .map_lookup_elem = array_map_lookup_elem, | |
137 | .map_update_elem = array_map_update_elem, | |
138 | .map_delete_elem = array_map_delete_elem, | |
139 | }; | |
140 | ||
a2c83fff | 141 | static struct bpf_map_type_list array_type __read_mostly = { |
28fbcfa0 AS |
142 | .ops = &array_ops, |
143 | .type = BPF_MAP_TYPE_ARRAY, | |
144 | }; | |
145 | ||
146 | static int __init register_array_map(void) | |
147 | { | |
a2c83fff | 148 | bpf_register_map_type(&array_type); |
28fbcfa0 AS |
149 | return 0; |
150 | } | |
151 | late_initcall(register_array_map); | |
04fd61ab AS |
152 | |
153 | static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr) | |
154 | { | |
155 | /* only bpf_prog file descriptors can be stored in prog_array map */ | |
156 | if (attr->value_size != sizeof(u32)) | |
157 | return ERR_PTR(-EINVAL); | |
158 | return array_map_alloc(attr); | |
159 | } | |
160 | ||
161 | static void prog_array_map_free(struct bpf_map *map) | |
162 | { | |
163 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
164 | int i; | |
165 | ||
166 | synchronize_rcu(); | |
167 | ||
168 | /* make sure it's empty */ | |
169 | for (i = 0; i < array->map.max_entries; i++) | |
170 | BUG_ON(array->prog[i] != NULL); | |
171 | kvfree(array); | |
172 | } | |
173 | ||
174 | static void *prog_array_map_lookup_elem(struct bpf_map *map, void *key) | |
175 | { | |
176 | return NULL; | |
177 | } | |
178 | ||
179 | /* only called from syscall */ | |
180 | static int prog_array_map_update_elem(struct bpf_map *map, void *key, | |
181 | void *value, u64 map_flags) | |
182 | { | |
183 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
184 | struct bpf_prog *prog, *old_prog; | |
185 | u32 index = *(u32 *)key, ufd; | |
186 | ||
187 | if (map_flags != BPF_ANY) | |
188 | return -EINVAL; | |
189 | ||
190 | if (index >= array->map.max_entries) | |
191 | return -E2BIG; | |
192 | ||
193 | ufd = *(u32 *)value; | |
194 | prog = bpf_prog_get(ufd); | |
195 | if (IS_ERR(prog)) | |
196 | return PTR_ERR(prog); | |
197 | ||
198 | if (!bpf_prog_array_compatible(array, prog)) { | |
199 | bpf_prog_put(prog); | |
200 | return -EINVAL; | |
201 | } | |
202 | ||
203 | old_prog = xchg(array->prog + index, prog); | |
204 | if (old_prog) | |
abf2e7d6 | 205 | bpf_prog_put_rcu(old_prog); |
04fd61ab AS |
206 | |
207 | return 0; | |
208 | } | |
209 | ||
210 | static int prog_array_map_delete_elem(struct bpf_map *map, void *key) | |
211 | { | |
212 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
213 | struct bpf_prog *old_prog; | |
214 | u32 index = *(u32 *)key; | |
215 | ||
216 | if (index >= array->map.max_entries) | |
217 | return -E2BIG; | |
218 | ||
219 | old_prog = xchg(array->prog + index, NULL); | |
220 | if (old_prog) { | |
abf2e7d6 | 221 | bpf_prog_put_rcu(old_prog); |
04fd61ab AS |
222 | return 0; |
223 | } else { | |
224 | return -ENOENT; | |
225 | } | |
226 | } | |
227 | ||
228 | /* decrement refcnt of all bpf_progs that are stored in this map */ | |
229 | void bpf_prog_array_map_clear(struct bpf_map *map) | |
230 | { | |
231 | struct bpf_array *array = container_of(map, struct bpf_array, map); | |
232 | int i; | |
233 | ||
234 | for (i = 0; i < array->map.max_entries; i++) | |
235 | prog_array_map_delete_elem(map, &i); | |
236 | } | |
237 | ||
238 | static const struct bpf_map_ops prog_array_ops = { | |
239 | .map_alloc = prog_array_map_alloc, | |
240 | .map_free = prog_array_map_free, | |
241 | .map_get_next_key = array_map_get_next_key, | |
242 | .map_lookup_elem = prog_array_map_lookup_elem, | |
243 | .map_update_elem = prog_array_map_update_elem, | |
244 | .map_delete_elem = prog_array_map_delete_elem, | |
245 | }; | |
246 | ||
247 | static struct bpf_map_type_list prog_array_type __read_mostly = { | |
248 | .ops = &prog_array_ops, | |
249 | .type = BPF_MAP_TYPE_PROG_ARRAY, | |
250 | }; | |
251 | ||
252 | static int __init register_prog_array_map(void) | |
253 | { | |
254 | bpf_register_map_type(&prog_array_type); | |
255 | return 0; | |
256 | } | |
257 | late_initcall(register_prog_array_map); |