1
2#include <linux/bpf-cgroup.h>
3#include <linux/bpf.h>
4#include <linux/bpf_local_storage.h>
5#include <linux/btf.h>
6#include <linux/bug.h>
7#include <linux/filter.h>
8#include <linux/mm.h>
9#include <linux/rbtree.h>
10#include <linux/slab.h>
11#include <uapi/linux/btf.h>
12
13#ifdef CONFIG_CGROUP_BPF
14
15#include "../cgroup/cgroup-internal.h"
16
17#define LOCAL_STORAGE_CREATE_FLAG_MASK \
18 (BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK)
19
20struct bpf_cgroup_storage_map {
21 struct bpf_map map;
22
23 spinlock_t lock;
24 struct rb_root root;
25 struct list_head list;
26};
27
28static struct bpf_cgroup_storage_map *map_to_storage(struct bpf_map *map)
29{
30 return container_of(map, struct bpf_cgroup_storage_map, map);
31}
32
33static bool attach_type_isolated(const struct bpf_map *map)
34{
35 return map->key_size == sizeof(struct bpf_cgroup_storage_key);
36}
37
38static int bpf_cgroup_storage_key_cmp(const struct bpf_cgroup_storage_map *map,
39 const void *_key1, const void *_key2)
40{
41 if (attach_type_isolated(&map->map)) {
42 const struct bpf_cgroup_storage_key *key1 = _key1;
43 const struct bpf_cgroup_storage_key *key2 = _key2;
44
45 if (key1->cgroup_inode_id < key2->cgroup_inode_id)
46 return -1;
47 else if (key1->cgroup_inode_id > key2->cgroup_inode_id)
48 return 1;
49 else if (key1->attach_type < key2->attach_type)
50 return -1;
51 else if (key1->attach_type > key2->attach_type)
52 return 1;
53 } else {
54 const __u64 *cgroup_inode_id1 = _key1;
55 const __u64 *cgroup_inode_id2 = _key2;
56
57 if (*cgroup_inode_id1 < *cgroup_inode_id2)
58 return -1;
59 else if (*cgroup_inode_id1 > *cgroup_inode_id2)
60 return 1;
61 }
62 return 0;
63}
64
65struct bpf_cgroup_storage *
66cgroup_storage_lookup(struct bpf_cgroup_storage_map *map,
67 void *key, bool locked)
68{
69 struct rb_root *root = &map->root;
70 struct rb_node *node;
71
72 if (!locked)
73 spin_lock_bh(&map->lock);
74
75 node = root->rb_node;
76 while (node) {
77 struct bpf_cgroup_storage *storage;
78
79 storage = container_of(node, struct bpf_cgroup_storage, node);
80
81 switch (bpf_cgroup_storage_key_cmp(map, key, &storage->key)) {
82 case -1:
83 node = node->rb_left;
84 break;
85 case 1:
86 node = node->rb_right;
87 break;
88 default:
89 if (!locked)
90 spin_unlock_bh(&map->lock);
91 return storage;
92 }
93 }
94
95 if (!locked)
96 spin_unlock_bh(&map->lock);
97
98 return NULL;
99}
100
101static int cgroup_storage_insert(struct bpf_cgroup_storage_map *map,
102 struct bpf_cgroup_storage *storage)
103{
104 struct rb_root *root = &map->root;
105 struct rb_node **new = &(root->rb_node), *parent = NULL;
106
107 while (*new) {
108 struct bpf_cgroup_storage *this;
109
110 this = container_of(*new, struct bpf_cgroup_storage, node);
111
112 parent = *new;
113 switch (bpf_cgroup_storage_key_cmp(map, &storage->key, &this->key)) {
114 case -1:
115 new = &((*new)->rb_left);
116 break;
117 case 1:
118 new = &((*new)->rb_right);
119 break;
120 default:
121 return -EEXIST;
122 }
123 }
124
125 rb_link_node(&storage->node, parent, new);
126 rb_insert_color(&storage->node, root);
127
128 return 0;
129}
130
131static void *cgroup_storage_lookup_elem(struct bpf_map *_map, void *key)
132{
133 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
134 struct bpf_cgroup_storage *storage;
135
136 storage = cgroup_storage_lookup(map, key, false);
137 if (!storage)
138 return NULL;
139
140 return &READ_ONCE(storage->buf)->data[0];
141}
142
143static int cgroup_storage_update_elem(struct bpf_map *map, void *key,
144 void *value, u64 flags)
145{
146 struct bpf_cgroup_storage *storage;
147 struct bpf_storage_buffer *new;
148
149 if (unlikely(flags & ~(BPF_F_LOCK | BPF_EXIST)))
150 return -EINVAL;
151
152 if (unlikely((flags & BPF_F_LOCK) &&
153 !map_value_has_spin_lock(map)))
154 return -EINVAL;
155
156 storage = cgroup_storage_lookup((struct bpf_cgroup_storage_map *)map,
157 key, false);
158 if (!storage)
159 return -ENOENT;
160
161 if (flags & BPF_F_LOCK) {
162 copy_map_value_locked(map, storage->buf->data, value, false);
163 return 0;
164 }
165
166 new = bpf_map_kmalloc_node(map, sizeof(struct bpf_storage_buffer) +
167 map->value_size,
168 __GFP_ZERO | GFP_ATOMIC | __GFP_NOWARN,
169 map->numa_node);
170 if (!new)
171 return -ENOMEM;
172
173 memcpy(&new->data[0], value, map->value_size);
174 check_and_init_map_value(map, new->data);
175
176 new = xchg(&storage->buf, new);
177 kfree_rcu(new, rcu);
178
179 return 0;
180}
181
182int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,
183 void *value)
184{
185 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
186 struct bpf_cgroup_storage *storage;
187 int cpu, off = 0;
188 u32 size;
189
190 rcu_read_lock();
191 storage = cgroup_storage_lookup(map, key, false);
192 if (!storage) {
193 rcu_read_unlock();
194 return -ENOENT;
195 }
196
197
198
199
200
201 size = round_up(_map->value_size, 8);
202 for_each_possible_cpu(cpu) {
203 bpf_long_memcpy(value + off,
204 per_cpu_ptr(storage->percpu_buf, cpu), size);
205 off += size;
206 }
207 rcu_read_unlock();
208 return 0;
209}
210
211int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key,
212 void *value, u64 map_flags)
213{
214 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
215 struct bpf_cgroup_storage *storage;
216 int cpu, off = 0;
217 u32 size;
218
219 if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
220 return -EINVAL;
221
222 rcu_read_lock();
223 storage = cgroup_storage_lookup(map, key, false);
224 if (!storage) {
225 rcu_read_unlock();
226 return -ENOENT;
227 }
228
229
230
231
232
233
234
235 size = round_up(_map->value_size, 8);
236 for_each_possible_cpu(cpu) {
237 bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu),
238 value + off, size);
239 off += size;
240 }
241 rcu_read_unlock();
242 return 0;
243}
244
245static int cgroup_storage_get_next_key(struct bpf_map *_map, void *key,
246 void *_next_key)
247{
248 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
249 struct bpf_cgroup_storage *storage;
250
251 spin_lock_bh(&map->lock);
252
253 if (list_empty(&map->list))
254 goto enoent;
255
256 if (key) {
257 storage = cgroup_storage_lookup(map, key, true);
258 if (!storage)
259 goto enoent;
260
261 storage = list_next_entry(storage, list_map);
262 if (!storage)
263 goto enoent;
264 } else {
265 storage = list_first_entry(&map->list,
266 struct bpf_cgroup_storage, list_map);
267 }
268
269 spin_unlock_bh(&map->lock);
270
271 if (attach_type_isolated(&map->map)) {
272 struct bpf_cgroup_storage_key *next = _next_key;
273 *next = storage->key;
274 } else {
275 __u64 *next = _next_key;
276 *next = storage->key.cgroup_inode_id;
277 }
278 return 0;
279
280enoent:
281 spin_unlock_bh(&map->lock);
282 return -ENOENT;
283}
284
285static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
286{
287 __u32 max_value_size = BPF_LOCAL_STORAGE_MAX_VALUE_SIZE;
288 int numa_node = bpf_map_attr_numa_node(attr);
289 struct bpf_cgroup_storage_map *map;
290
291
292
293
294 if (attr->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
295 max_value_size = min_t(__u32, max_value_size,
296 PCPU_MIN_UNIT_SIZE);
297
298 if (attr->key_size != sizeof(struct bpf_cgroup_storage_key) &&
299 attr->key_size != sizeof(__u64))
300 return ERR_PTR(-EINVAL);
301
302 if (attr->value_size == 0)
303 return ERR_PTR(-EINVAL);
304
305 if (attr->value_size > max_value_size)
306 return ERR_PTR(-E2BIG);
307
308 if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
309 !bpf_map_flags_access_ok(attr->map_flags))
310 return ERR_PTR(-EINVAL);
311
312 if (attr->max_entries)
313
314 return ERR_PTR(-EINVAL);
315
316 map = kmalloc_node(sizeof(struct bpf_cgroup_storage_map),
317 __GFP_ZERO | GFP_USER | __GFP_ACCOUNT, numa_node);
318 if (!map)
319 return ERR_PTR(-ENOMEM);
320
321
322 bpf_map_init_from_attr(&map->map, attr);
323
324 spin_lock_init(&map->lock);
325 map->root = RB_ROOT;
326 INIT_LIST_HEAD(&map->list);
327
328 return &map->map;
329}
330
331static void cgroup_storage_map_free(struct bpf_map *_map)
332{
333 struct bpf_cgroup_storage_map *map = map_to_storage(_map);
334 struct list_head *storages = &map->list;
335 struct bpf_cgroup_storage *storage, *stmp;
336
337 mutex_lock(&cgroup_mutex);
338
339 list_for_each_entry_safe(storage, stmp, storages, list_map) {
340 bpf_cgroup_storage_unlink(storage);
341 bpf_cgroup_storage_free(storage);
342 }
343
344 mutex_unlock(&cgroup_mutex);
345
346 WARN_ON(!RB_EMPTY_ROOT(&map->root));
347 WARN_ON(!list_empty(&map->list));
348
349 kfree(map);
350}
351
352static int cgroup_storage_delete_elem(struct bpf_map *map, void *key)
353{
354 return -EINVAL;
355}
356
357static int cgroup_storage_check_btf(const struct bpf_map *map,
358 const struct btf *btf,
359 const struct btf_type *key_type,
360 const struct btf_type *value_type)
361{
362 if (attach_type_isolated(map)) {
363 struct btf_member *m;
364 u32 offset, size;
365
366
367
368
369
370
371
372
373
374
375
376
377 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_STRUCT ||
378 BTF_INFO_VLEN(key_type->info) != 2)
379 return -EINVAL;
380
381
382
383
384 m = (struct btf_member *)(key_type + 1);
385 size = sizeof_field(struct bpf_cgroup_storage_key, cgroup_inode_id);
386 if (!btf_member_is_reg_int(btf, key_type, m, 0, size))
387 return -EINVAL;
388
389
390
391
392 m++;
393 offset = offsetof(struct bpf_cgroup_storage_key, attach_type);
394 size = sizeof_field(struct bpf_cgroup_storage_key, attach_type);
395 if (!btf_member_is_reg_int(btf, key_type, m, offset, size))
396 return -EINVAL;
397 } else {
398 u32 int_data;
399
400
401
402
403
404 if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
405 return -EINVAL;
406
407 int_data = *(u32 *)(key_type + 1);
408 if (BTF_INT_BITS(int_data) != 64 || BTF_INT_OFFSET(int_data))
409 return -EINVAL;
410 }
411
412 return 0;
413}
414
415static void cgroup_storage_seq_show_elem(struct bpf_map *map, void *key,
416 struct seq_file *m)
417{
418 enum bpf_cgroup_storage_type stype;
419 struct bpf_cgroup_storage *storage;
420 int cpu;
421
422 rcu_read_lock();
423 storage = cgroup_storage_lookup(map_to_storage(map), key, false);
424 if (!storage) {
425 rcu_read_unlock();
426 return;
427 }
428
429 btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
430 stype = cgroup_storage_type(map);
431 if (stype == BPF_CGROUP_STORAGE_SHARED) {
432 seq_puts(m, ": ");
433 btf_type_seq_show(map->btf, map->btf_value_type_id,
434 &READ_ONCE(storage->buf)->data[0], m);
435 seq_puts(m, "\n");
436 } else {
437 seq_puts(m, ": {\n");
438 for_each_possible_cpu(cpu) {
439 seq_printf(m, "\tcpu%d: ", cpu);
440 btf_type_seq_show(map->btf, map->btf_value_type_id,
441 per_cpu_ptr(storage->percpu_buf, cpu),
442 m);
443 seq_puts(m, "\n");
444 }
445 seq_puts(m, "}\n");
446 }
447 rcu_read_unlock();
448}
449
450static int cgroup_storage_map_btf_id;
451const struct bpf_map_ops cgroup_storage_map_ops = {
452 .map_alloc = cgroup_storage_map_alloc,
453 .map_free = cgroup_storage_map_free,
454 .map_get_next_key = cgroup_storage_get_next_key,
455 .map_lookup_elem = cgroup_storage_lookup_elem,
456 .map_update_elem = cgroup_storage_update_elem,
457 .map_delete_elem = cgroup_storage_delete_elem,
458 .map_check_btf = cgroup_storage_check_btf,
459 .map_seq_show_elem = cgroup_storage_seq_show_elem,
460 .map_btf_name = "bpf_cgroup_storage_map",
461 .map_btf_id = &cgroup_storage_map_btf_id,
462};
463
464int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map)
465{
466 enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
467
468 if (aux->cgroup_storage[stype] &&
469 aux->cgroup_storage[stype] != _map)
470 return -EBUSY;
471
472 aux->cgroup_storage[stype] = _map;
473 return 0;
474}
475
476static size_t bpf_cgroup_storage_calculate_size(struct bpf_map *map, u32 *pages)
477{
478 size_t size;
479
480 if (cgroup_storage_type(map) == BPF_CGROUP_STORAGE_SHARED) {
481 size = sizeof(struct bpf_storage_buffer) + map->value_size;
482 *pages = round_up(sizeof(struct bpf_cgroup_storage) + size,
483 PAGE_SIZE) >> PAGE_SHIFT;
484 } else {
485 size = map->value_size;
486 *pages = round_up(round_up(size, 8) * num_possible_cpus(),
487 PAGE_SIZE) >> PAGE_SHIFT;
488 }
489
490 return size;
491}
492
493struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
494 enum bpf_cgroup_storage_type stype)
495{
496 const gfp_t gfp = __GFP_ZERO | GFP_USER;
497 struct bpf_cgroup_storage *storage;
498 struct bpf_map *map;
499 size_t size;
500 u32 pages;
501
502 map = prog->aux->cgroup_storage[stype];
503 if (!map)
504 return NULL;
505
506 size = bpf_cgroup_storage_calculate_size(map, &pages);
507
508 storage = bpf_map_kmalloc_node(map, sizeof(struct bpf_cgroup_storage),
509 gfp, map->numa_node);
510 if (!storage)
511 goto enomem;
512
513 if (stype == BPF_CGROUP_STORAGE_SHARED) {
514 storage->buf = bpf_map_kmalloc_node(map, size, gfp,
515 map->numa_node);
516 if (!storage->buf)
517 goto enomem;
518 check_and_init_map_value(map, storage->buf->data);
519 } else {
520 storage->percpu_buf = bpf_map_alloc_percpu(map, size, 8, gfp);
521 if (!storage->percpu_buf)
522 goto enomem;
523 }
524
525 storage->map = (struct bpf_cgroup_storage_map *)map;
526
527 return storage;
528
529enomem:
530 kfree(storage);
531 return ERR_PTR(-ENOMEM);
532}
533
534static void free_shared_cgroup_storage_rcu(struct rcu_head *rcu)
535{
536 struct bpf_cgroup_storage *storage =
537 container_of(rcu, struct bpf_cgroup_storage, rcu);
538
539 kfree(storage->buf);
540 kfree(storage);
541}
542
543static void free_percpu_cgroup_storage_rcu(struct rcu_head *rcu)
544{
545 struct bpf_cgroup_storage *storage =
546 container_of(rcu, struct bpf_cgroup_storage, rcu);
547
548 free_percpu(storage->percpu_buf);
549 kfree(storage);
550}
551
552void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage)
553{
554 enum bpf_cgroup_storage_type stype;
555 struct bpf_map *map;
556
557 if (!storage)
558 return;
559
560 map = &storage->map->map;
561 stype = cgroup_storage_type(map);
562 if (stype == BPF_CGROUP_STORAGE_SHARED)
563 call_rcu(&storage->rcu, free_shared_cgroup_storage_rcu);
564 else
565 call_rcu(&storage->rcu, free_percpu_cgroup_storage_rcu);
566}
567
568void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
569 struct cgroup *cgroup,
570 enum bpf_attach_type type)
571{
572 struct bpf_cgroup_storage_map *map;
573
574 if (!storage)
575 return;
576
577 storage->key.attach_type = type;
578 storage->key.cgroup_inode_id = cgroup_id(cgroup);
579
580 map = storage->map;
581
582 spin_lock_bh(&map->lock);
583 WARN_ON(cgroup_storage_insert(map, storage));
584 list_add(&storage->list_map, &map->list);
585 list_add(&storage->list_cg, &cgroup->bpf.storages);
586 spin_unlock_bh(&map->lock);
587}
588
589void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage)
590{
591 struct bpf_cgroup_storage_map *map;
592 struct rb_root *root;
593
594 if (!storage)
595 return;
596
597 map = storage->map;
598
599 spin_lock_bh(&map->lock);
600 root = &map->root;
601 rb_erase(&storage->node, root);
602
603 list_del(&storage->list_map);
604 list_del(&storage->list_cg);
605 spin_unlock_bh(&map->lock);
606}
607
608#endif
609