Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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> |
Alexei Starovoitov | 04fd61a | 2015-05-19 16:59:03 -0700 | [diff] [blame^] | 17 | #include <linux/filter.h> |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 18 | |
| 19 | /* Called from syscall */ |
| 20 | static struct bpf_map *array_map_alloc(union bpf_attr *attr) |
| 21 | { |
| 22 | struct bpf_array *array; |
Alexei Starovoitov | daaf427 | 2014-11-18 17:32:16 -0800 | [diff] [blame] | 23 | u32 elem_size, array_size; |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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 | |
Alexei Starovoitov | daaf427 | 2014-11-18 17:32:16 -0800 | [diff] [blame] | 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 | |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 39 | /* allocate all map elements and zero-initialize them */ |
Alexei Starovoitov | daaf427 | 2014-11-18 17:32:16 -0800 | [diff] [blame] | 40 | array = kzalloc(array_size, GFP_USER | __GFP_NOWARN); |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 41 | if (!array) { |
Alexei Starovoitov | daaf427 | 2014-11-18 17:32:16 -0800 | [diff] [blame] | 42 | array = vzalloc(array_size); |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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; |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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) |
Alexei Starovoitov | daaf427 | 2014-11-18 17:32:16 -0800 | [diff] [blame] | 104 | /* all elements already exist */ |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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 | |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 132 | static const struct bpf_map_ops array_ops = { |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 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 | |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 141 | static struct bpf_map_type_list array_type __read_mostly = { |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 142 | .ops = &array_ops, |
| 143 | .type = BPF_MAP_TYPE_ARRAY, |
| 144 | }; |
| 145 | |
| 146 | static int __init register_array_map(void) |
| 147 | { |
Daniel Borkmann | a2c83ff | 2015-03-01 12:31:42 +0100 | [diff] [blame] | 148 | bpf_register_map_type(&array_type); |
Alexei Starovoitov | 28fbcfa | 2014-11-13 17:36:46 -0800 | [diff] [blame] | 149 | return 0; |
| 150 | } |
| 151 | late_initcall(register_array_map); |
Alexei Starovoitov | 04fd61a | 2015-05-19 16:59:03 -0700 | [diff] [blame^] | 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) |
| 205 | bpf_prog_put(old_prog); |
| 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) { |
| 221 | bpf_prog_put(old_prog); |
| 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); |