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604326b4 DB |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ | |
3 | ||
4 | #include <linux/bpf.h> | |
5 | #include <linux/filter.h> | |
6 | #include <linux/errno.h> | |
7 | #include <linux/file.h> | |
8 | #include <linux/net.h> | |
9 | #include <linux/workqueue.h> | |
10 | #include <linux/skmsg.h> | |
11 | #include <linux/list.h> | |
12 | #include <linux/jhash.h> | |
13 | ||
14 | struct bpf_stab { | |
15 | struct bpf_map map; | |
16 | struct sock **sks; | |
17 | struct sk_psock_progs progs; | |
18 | raw_spinlock_t lock; | |
19 | }; | |
20 | ||
21 | #define SOCK_CREATE_FLAG_MASK \ | |
22 | (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) | |
23 | ||
24 | static struct bpf_map *sock_map_alloc(union bpf_attr *attr) | |
25 | { | |
26 | struct bpf_stab *stab; | |
27 | u64 cost; | |
28 | int err; | |
29 | ||
30 | if (!capable(CAP_NET_ADMIN)) | |
31 | return ERR_PTR(-EPERM); | |
32 | if (attr->max_entries == 0 || | |
33 | attr->key_size != 4 || | |
34 | attr->value_size != 4 || | |
35 | attr->map_flags & ~SOCK_CREATE_FLAG_MASK) | |
36 | return ERR_PTR(-EINVAL); | |
37 | ||
38 | stab = kzalloc(sizeof(*stab), GFP_USER); | |
39 | if (!stab) | |
40 | return ERR_PTR(-ENOMEM); | |
41 | ||
42 | bpf_map_init_from_attr(&stab->map, attr); | |
43 | raw_spin_lock_init(&stab->lock); | |
44 | ||
45 | /* Make sure page count doesn't overflow. */ | |
46 | cost = (u64) stab->map.max_entries * sizeof(struct sock *); | |
47 | if (cost >= U32_MAX - PAGE_SIZE) { | |
48 | err = -EINVAL; | |
49 | goto free_stab; | |
50 | } | |
51 | ||
52 | stab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; | |
53 | err = bpf_map_precharge_memlock(stab->map.pages); | |
54 | if (err) | |
55 | goto free_stab; | |
56 | ||
57 | stab->sks = bpf_map_area_alloc(stab->map.max_entries * | |
58 | sizeof(struct sock *), | |
59 | stab->map.numa_node); | |
60 | if (stab->sks) | |
61 | return &stab->map; | |
62 | err = -ENOMEM; | |
63 | free_stab: | |
64 | kfree(stab); | |
65 | return ERR_PTR(err); | |
66 | } | |
67 | ||
68 | int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog) | |
69 | { | |
70 | u32 ufd = attr->target_fd; | |
71 | struct bpf_map *map; | |
72 | struct fd f; | |
73 | int ret; | |
74 | ||
75 | f = fdget(ufd); | |
76 | map = __bpf_map_get(f); | |
77 | if (IS_ERR(map)) | |
78 | return PTR_ERR(map); | |
79 | ret = sock_map_prog_update(map, prog, attr->attach_type); | |
80 | fdput(f); | |
81 | return ret; | |
82 | } | |
83 | ||
84 | static void sock_map_sk_acquire(struct sock *sk) | |
85 | __acquires(&sk->sk_lock.slock) | |
86 | { | |
87 | lock_sock(sk); | |
88 | preempt_disable(); | |
89 | rcu_read_lock(); | |
90 | } | |
91 | ||
92 | static void sock_map_sk_release(struct sock *sk) | |
93 | __releases(&sk->sk_lock.slock) | |
94 | { | |
95 | rcu_read_unlock(); | |
96 | preempt_enable(); | |
97 | release_sock(sk); | |
98 | } | |
99 | ||
100 | static void sock_map_add_link(struct sk_psock *psock, | |
101 | struct sk_psock_link *link, | |
102 | struct bpf_map *map, void *link_raw) | |
103 | { | |
104 | link->link_raw = link_raw; | |
105 | link->map = map; | |
106 | spin_lock_bh(&psock->link_lock); | |
107 | list_add_tail(&link->list, &psock->link); | |
108 | spin_unlock_bh(&psock->link_lock); | |
109 | } | |
110 | ||
111 | static void sock_map_del_link(struct sock *sk, | |
112 | struct sk_psock *psock, void *link_raw) | |
113 | { | |
114 | struct sk_psock_link *link, *tmp; | |
115 | bool strp_stop = false; | |
116 | ||
117 | spin_lock_bh(&psock->link_lock); | |
118 | list_for_each_entry_safe(link, tmp, &psock->link, list) { | |
119 | if (link->link_raw == link_raw) { | |
120 | struct bpf_map *map = link->map; | |
121 | struct bpf_stab *stab = container_of(map, struct bpf_stab, | |
122 | map); | |
123 | if (psock->parser.enabled && stab->progs.skb_parser) | |
124 | strp_stop = true; | |
125 | list_del(&link->list); | |
126 | sk_psock_free_link(link); | |
127 | } | |
128 | } | |
129 | spin_unlock_bh(&psock->link_lock); | |
130 | if (strp_stop) { | |
131 | write_lock_bh(&sk->sk_callback_lock); | |
132 | sk_psock_stop_strp(sk, psock); | |
133 | write_unlock_bh(&sk->sk_callback_lock); | |
134 | } | |
135 | } | |
136 | ||
137 | static void sock_map_unref(struct sock *sk, void *link_raw) | |
138 | { | |
139 | struct sk_psock *psock = sk_psock(sk); | |
140 | ||
141 | if (likely(psock)) { | |
142 | sock_map_del_link(sk, psock, link_raw); | |
143 | sk_psock_put(sk, psock); | |
144 | } | |
145 | } | |
146 | ||
147 | static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs, | |
148 | struct sock *sk) | |
149 | { | |
150 | struct bpf_prog *msg_parser, *skb_parser, *skb_verdict; | |
151 | bool skb_progs, sk_psock_is_new = false; | |
152 | struct sk_psock *psock; | |
153 | int ret; | |
154 | ||
155 | skb_verdict = READ_ONCE(progs->skb_verdict); | |
156 | skb_parser = READ_ONCE(progs->skb_parser); | |
157 | skb_progs = skb_parser && skb_verdict; | |
158 | if (skb_progs) { | |
159 | skb_verdict = bpf_prog_inc_not_zero(skb_verdict); | |
160 | if (IS_ERR(skb_verdict)) | |
161 | return PTR_ERR(skb_verdict); | |
162 | skb_parser = bpf_prog_inc_not_zero(skb_parser); | |
163 | if (IS_ERR(skb_parser)) { | |
164 | bpf_prog_put(skb_verdict); | |
165 | return PTR_ERR(skb_parser); | |
166 | } | |
167 | } | |
168 | ||
169 | msg_parser = READ_ONCE(progs->msg_parser); | |
170 | if (msg_parser) { | |
171 | msg_parser = bpf_prog_inc_not_zero(msg_parser); | |
172 | if (IS_ERR(msg_parser)) { | |
173 | ret = PTR_ERR(msg_parser); | |
174 | goto out; | |
175 | } | |
176 | } | |
177 | ||
5032d079 JF |
178 | psock = sk_psock_get_checked(sk); |
179 | if (IS_ERR(psock)) { | |
180 | ret = PTR_ERR(psock); | |
181 | goto out_progs; | |
182 | } | |
183 | ||
604326b4 | 184 | if (psock) { |
604326b4 DB |
185 | if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) || |
186 | (skb_progs && READ_ONCE(psock->progs.skb_parser))) { | |
187 | sk_psock_put(sk, psock); | |
188 | ret = -EBUSY; | |
189 | goto out_progs; | |
190 | } | |
191 | } else { | |
192 | psock = sk_psock_init(sk, map->numa_node); | |
193 | if (!psock) { | |
194 | ret = -ENOMEM; | |
195 | goto out_progs; | |
196 | } | |
197 | sk_psock_is_new = true; | |
198 | } | |
199 | ||
200 | if (msg_parser) | |
201 | psock_set_prog(&psock->progs.msg_parser, msg_parser); | |
202 | if (sk_psock_is_new) { | |
203 | ret = tcp_bpf_init(sk); | |
204 | if (ret < 0) | |
205 | goto out_drop; | |
206 | } else { | |
207 | tcp_bpf_reinit(sk); | |
208 | } | |
209 | ||
210 | write_lock_bh(&sk->sk_callback_lock); | |
211 | if (skb_progs && !psock->parser.enabled) { | |
212 | ret = sk_psock_init_strp(sk, psock); | |
213 | if (ret) { | |
214 | write_unlock_bh(&sk->sk_callback_lock); | |
215 | goto out_drop; | |
216 | } | |
217 | psock_set_prog(&psock->progs.skb_verdict, skb_verdict); | |
218 | psock_set_prog(&psock->progs.skb_parser, skb_parser); | |
219 | sk_psock_start_strp(sk, psock); | |
220 | } | |
221 | write_unlock_bh(&sk->sk_callback_lock); | |
222 | return 0; | |
223 | out_drop: | |
224 | sk_psock_put(sk, psock); | |
225 | out_progs: | |
226 | if (msg_parser) | |
227 | bpf_prog_put(msg_parser); | |
228 | out: | |
229 | if (skb_progs) { | |
230 | bpf_prog_put(skb_verdict); | |
231 | bpf_prog_put(skb_parser); | |
232 | } | |
233 | return ret; | |
234 | } | |
235 | ||
236 | static void sock_map_free(struct bpf_map *map) | |
237 | { | |
238 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
239 | int i; | |
240 | ||
241 | synchronize_rcu(); | |
242 | rcu_read_lock(); | |
243 | raw_spin_lock_bh(&stab->lock); | |
244 | for (i = 0; i < stab->map.max_entries; i++) { | |
245 | struct sock **psk = &stab->sks[i]; | |
246 | struct sock *sk; | |
247 | ||
248 | sk = xchg(psk, NULL); | |
249 | if (sk) | |
250 | sock_map_unref(sk, psk); | |
251 | } | |
252 | raw_spin_unlock_bh(&stab->lock); | |
253 | rcu_read_unlock(); | |
254 | ||
255 | bpf_map_area_free(stab->sks); | |
256 | kfree(stab); | |
257 | } | |
258 | ||
259 | static void sock_map_release_progs(struct bpf_map *map) | |
260 | { | |
261 | psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs); | |
262 | } | |
263 | ||
264 | static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key) | |
265 | { | |
266 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
267 | ||
268 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
269 | ||
270 | if (unlikely(key >= map->max_entries)) | |
271 | return NULL; | |
272 | return READ_ONCE(stab->sks[key]); | |
273 | } | |
274 | ||
275 | static void *sock_map_lookup(struct bpf_map *map, void *key) | |
276 | { | |
277 | return ERR_PTR(-EOPNOTSUPP); | |
278 | } | |
279 | ||
280 | static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test, | |
281 | struct sock **psk) | |
282 | { | |
283 | struct sock *sk; | |
284 | ||
285 | raw_spin_lock_bh(&stab->lock); | |
286 | sk = *psk; | |
287 | if (!sk_test || sk_test == sk) | |
288 | *psk = NULL; | |
289 | raw_spin_unlock_bh(&stab->lock); | |
290 | if (unlikely(!sk)) | |
291 | return -EINVAL; | |
292 | sock_map_unref(sk, psk); | |
293 | return 0; | |
294 | } | |
295 | ||
296 | static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk, | |
297 | void *link_raw) | |
298 | { | |
299 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
300 | ||
301 | __sock_map_delete(stab, sk, link_raw); | |
302 | } | |
303 | ||
304 | static int sock_map_delete_elem(struct bpf_map *map, void *key) | |
305 | { | |
306 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
307 | u32 i = *(u32 *)key; | |
308 | struct sock **psk; | |
309 | ||
310 | if (unlikely(i >= map->max_entries)) | |
311 | return -EINVAL; | |
312 | ||
313 | psk = &stab->sks[i]; | |
314 | return __sock_map_delete(stab, NULL, psk); | |
315 | } | |
316 | ||
317 | static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next) | |
318 | { | |
319 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
320 | u32 i = key ? *(u32 *)key : U32_MAX; | |
321 | u32 *key_next = next; | |
322 | ||
323 | if (i == stab->map.max_entries - 1) | |
324 | return -ENOENT; | |
325 | if (i >= stab->map.max_entries) | |
326 | *key_next = 0; | |
327 | else | |
328 | *key_next = i + 1; | |
329 | return 0; | |
330 | } | |
331 | ||
332 | static int sock_map_update_common(struct bpf_map *map, u32 idx, | |
333 | struct sock *sk, u64 flags) | |
334 | { | |
335 | struct bpf_stab *stab = container_of(map, struct bpf_stab, map); | |
336 | struct sk_psock_link *link; | |
337 | struct sk_psock *psock; | |
338 | struct sock *osk; | |
339 | int ret; | |
340 | ||
341 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
342 | if (unlikely(flags > BPF_EXIST)) | |
343 | return -EINVAL; | |
344 | if (unlikely(idx >= map->max_entries)) | |
345 | return -E2BIG; | |
346 | ||
347 | link = sk_psock_init_link(); | |
348 | if (!link) | |
349 | return -ENOMEM; | |
350 | ||
351 | ret = sock_map_link(map, &stab->progs, sk); | |
352 | if (ret < 0) | |
353 | goto out_free; | |
354 | ||
355 | psock = sk_psock(sk); | |
356 | WARN_ON_ONCE(!psock); | |
357 | ||
358 | raw_spin_lock_bh(&stab->lock); | |
359 | osk = stab->sks[idx]; | |
360 | if (osk && flags == BPF_NOEXIST) { | |
361 | ret = -EEXIST; | |
362 | goto out_unlock; | |
363 | } else if (!osk && flags == BPF_EXIST) { | |
364 | ret = -ENOENT; | |
365 | goto out_unlock; | |
366 | } | |
367 | ||
368 | sock_map_add_link(psock, link, map, &stab->sks[idx]); | |
369 | stab->sks[idx] = sk; | |
370 | if (osk) | |
371 | sock_map_unref(osk, &stab->sks[idx]); | |
372 | raw_spin_unlock_bh(&stab->lock); | |
373 | return 0; | |
374 | out_unlock: | |
375 | raw_spin_unlock_bh(&stab->lock); | |
376 | if (psock) | |
377 | sk_psock_put(sk, psock); | |
378 | out_free: | |
379 | sk_psock_free_link(link); | |
380 | return ret; | |
381 | } | |
382 | ||
383 | static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops) | |
384 | { | |
385 | return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB || | |
386 | ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB; | |
387 | } | |
388 | ||
389 | static bool sock_map_sk_is_suitable(const struct sock *sk) | |
390 | { | |
391 | return sk->sk_type == SOCK_STREAM && | |
392 | sk->sk_protocol == IPPROTO_TCP; | |
393 | } | |
394 | ||
395 | static int sock_map_update_elem(struct bpf_map *map, void *key, | |
396 | void *value, u64 flags) | |
397 | { | |
398 | u32 ufd = *(u32 *)value; | |
399 | u32 idx = *(u32 *)key; | |
400 | struct socket *sock; | |
401 | struct sock *sk; | |
402 | int ret; | |
403 | ||
404 | sock = sockfd_lookup(ufd, &ret); | |
405 | if (!sock) | |
406 | return ret; | |
407 | sk = sock->sk; | |
408 | if (!sk) { | |
409 | ret = -EINVAL; | |
410 | goto out; | |
411 | } | |
412 | if (!sock_map_sk_is_suitable(sk) || | |
413 | sk->sk_state != TCP_ESTABLISHED) { | |
414 | ret = -EOPNOTSUPP; | |
415 | goto out; | |
416 | } | |
417 | ||
418 | sock_map_sk_acquire(sk); | |
419 | ret = sock_map_update_common(map, idx, sk, flags); | |
420 | sock_map_sk_release(sk); | |
421 | out: | |
422 | fput(sock->file); | |
423 | return ret; | |
424 | } | |
425 | ||
426 | BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops, | |
427 | struct bpf_map *, map, void *, key, u64, flags) | |
428 | { | |
429 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
430 | ||
431 | if (likely(sock_map_sk_is_suitable(sops->sk) && | |
432 | sock_map_op_okay(sops))) | |
433 | return sock_map_update_common(map, *(u32 *)key, sops->sk, | |
434 | flags); | |
435 | return -EOPNOTSUPP; | |
436 | } | |
437 | ||
438 | const struct bpf_func_proto bpf_sock_map_update_proto = { | |
439 | .func = bpf_sock_map_update, | |
440 | .gpl_only = false, | |
441 | .pkt_access = true, | |
442 | .ret_type = RET_INTEGER, | |
443 | .arg1_type = ARG_PTR_TO_CTX, | |
444 | .arg2_type = ARG_CONST_MAP_PTR, | |
445 | .arg3_type = ARG_PTR_TO_MAP_KEY, | |
446 | .arg4_type = ARG_ANYTHING, | |
447 | }; | |
448 | ||
449 | BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb, | |
450 | struct bpf_map *, map, u32, key, u64, flags) | |
451 | { | |
452 | struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); | |
453 | ||
454 | if (unlikely(flags & ~(BPF_F_INGRESS))) | |
455 | return SK_DROP; | |
456 | tcb->bpf.flags = flags; | |
457 | tcb->bpf.sk_redir = __sock_map_lookup_elem(map, key); | |
458 | if (!tcb->bpf.sk_redir) | |
459 | return SK_DROP; | |
460 | return SK_PASS; | |
461 | } | |
462 | ||
463 | const struct bpf_func_proto bpf_sk_redirect_map_proto = { | |
464 | .func = bpf_sk_redirect_map, | |
465 | .gpl_only = false, | |
466 | .ret_type = RET_INTEGER, | |
467 | .arg1_type = ARG_PTR_TO_CTX, | |
468 | .arg2_type = ARG_CONST_MAP_PTR, | |
469 | .arg3_type = ARG_ANYTHING, | |
470 | .arg4_type = ARG_ANYTHING, | |
471 | }; | |
472 | ||
473 | BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg, | |
474 | struct bpf_map *, map, u32, key, u64, flags) | |
475 | { | |
476 | if (unlikely(flags & ~(BPF_F_INGRESS))) | |
477 | return SK_DROP; | |
478 | msg->flags = flags; | |
479 | msg->sk_redir = __sock_map_lookup_elem(map, key); | |
480 | if (!msg->sk_redir) | |
481 | return SK_DROP; | |
482 | return SK_PASS; | |
483 | } | |
484 | ||
485 | const struct bpf_func_proto bpf_msg_redirect_map_proto = { | |
486 | .func = bpf_msg_redirect_map, | |
487 | .gpl_only = false, | |
488 | .ret_type = RET_INTEGER, | |
489 | .arg1_type = ARG_PTR_TO_CTX, | |
490 | .arg2_type = ARG_CONST_MAP_PTR, | |
491 | .arg3_type = ARG_ANYTHING, | |
492 | .arg4_type = ARG_ANYTHING, | |
493 | }; | |
494 | ||
495 | const struct bpf_map_ops sock_map_ops = { | |
496 | .map_alloc = sock_map_alloc, | |
497 | .map_free = sock_map_free, | |
498 | .map_get_next_key = sock_map_get_next_key, | |
499 | .map_update_elem = sock_map_update_elem, | |
500 | .map_delete_elem = sock_map_delete_elem, | |
501 | .map_lookup_elem = sock_map_lookup, | |
502 | .map_release_uref = sock_map_release_progs, | |
503 | .map_check_btf = map_check_no_btf, | |
504 | }; | |
505 | ||
506 | struct bpf_htab_elem { | |
507 | struct rcu_head rcu; | |
508 | u32 hash; | |
509 | struct sock *sk; | |
510 | struct hlist_node node; | |
511 | u8 key[0]; | |
512 | }; | |
513 | ||
514 | struct bpf_htab_bucket { | |
515 | struct hlist_head head; | |
516 | raw_spinlock_t lock; | |
517 | }; | |
518 | ||
519 | struct bpf_htab { | |
520 | struct bpf_map map; | |
521 | struct bpf_htab_bucket *buckets; | |
522 | u32 buckets_num; | |
523 | u32 elem_size; | |
524 | struct sk_psock_progs progs; | |
525 | atomic_t count; | |
526 | }; | |
527 | ||
528 | static inline u32 sock_hash_bucket_hash(const void *key, u32 len) | |
529 | { | |
530 | return jhash(key, len, 0); | |
531 | } | |
532 | ||
533 | static struct bpf_htab_bucket *sock_hash_select_bucket(struct bpf_htab *htab, | |
534 | u32 hash) | |
535 | { | |
536 | return &htab->buckets[hash & (htab->buckets_num - 1)]; | |
537 | } | |
538 | ||
539 | static struct bpf_htab_elem * | |
540 | sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key, | |
541 | u32 key_size) | |
542 | { | |
543 | struct bpf_htab_elem *elem; | |
544 | ||
545 | hlist_for_each_entry_rcu(elem, head, node) { | |
546 | if (elem->hash == hash && | |
547 | !memcmp(&elem->key, key, key_size)) | |
548 | return elem; | |
549 | } | |
550 | ||
551 | return NULL; | |
552 | } | |
553 | ||
554 | static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key) | |
555 | { | |
556 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
557 | u32 key_size = map->key_size, hash; | |
558 | struct bpf_htab_bucket *bucket; | |
559 | struct bpf_htab_elem *elem; | |
560 | ||
561 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
562 | ||
563 | hash = sock_hash_bucket_hash(key, key_size); | |
564 | bucket = sock_hash_select_bucket(htab, hash); | |
565 | elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); | |
566 | ||
567 | return elem ? elem->sk : NULL; | |
568 | } | |
569 | ||
570 | static void sock_hash_free_elem(struct bpf_htab *htab, | |
571 | struct bpf_htab_elem *elem) | |
572 | { | |
573 | atomic_dec(&htab->count); | |
574 | kfree_rcu(elem, rcu); | |
575 | } | |
576 | ||
577 | static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk, | |
578 | void *link_raw) | |
579 | { | |
580 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
581 | struct bpf_htab_elem *elem_probe, *elem = link_raw; | |
582 | struct bpf_htab_bucket *bucket; | |
583 | ||
584 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
585 | bucket = sock_hash_select_bucket(htab, elem->hash); | |
586 | ||
587 | /* elem may be deleted in parallel from the map, but access here | |
588 | * is okay since it's going away only after RCU grace period. | |
589 | * However, we need to check whether it's still present. | |
590 | */ | |
591 | raw_spin_lock_bh(&bucket->lock); | |
592 | elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash, | |
593 | elem->key, map->key_size); | |
594 | if (elem_probe && elem_probe == elem) { | |
595 | hlist_del_rcu(&elem->node); | |
596 | sock_map_unref(elem->sk, elem); | |
597 | sock_hash_free_elem(htab, elem); | |
598 | } | |
599 | raw_spin_unlock_bh(&bucket->lock); | |
600 | } | |
601 | ||
602 | static int sock_hash_delete_elem(struct bpf_map *map, void *key) | |
603 | { | |
604 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
605 | u32 hash, key_size = map->key_size; | |
606 | struct bpf_htab_bucket *bucket; | |
607 | struct bpf_htab_elem *elem; | |
608 | int ret = -ENOENT; | |
609 | ||
610 | hash = sock_hash_bucket_hash(key, key_size); | |
611 | bucket = sock_hash_select_bucket(htab, hash); | |
612 | ||
613 | raw_spin_lock_bh(&bucket->lock); | |
614 | elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); | |
615 | if (elem) { | |
616 | hlist_del_rcu(&elem->node); | |
617 | sock_map_unref(elem->sk, elem); | |
618 | sock_hash_free_elem(htab, elem); | |
619 | ret = 0; | |
620 | } | |
621 | raw_spin_unlock_bh(&bucket->lock); | |
622 | return ret; | |
623 | } | |
624 | ||
625 | static struct bpf_htab_elem *sock_hash_alloc_elem(struct bpf_htab *htab, | |
626 | void *key, u32 key_size, | |
627 | u32 hash, struct sock *sk, | |
628 | struct bpf_htab_elem *old) | |
629 | { | |
630 | struct bpf_htab_elem *new; | |
631 | ||
632 | if (atomic_inc_return(&htab->count) > htab->map.max_entries) { | |
633 | if (!old) { | |
634 | atomic_dec(&htab->count); | |
635 | return ERR_PTR(-E2BIG); | |
636 | } | |
637 | } | |
638 | ||
639 | new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN, | |
640 | htab->map.numa_node); | |
641 | if (!new) { | |
642 | atomic_dec(&htab->count); | |
643 | return ERR_PTR(-ENOMEM); | |
644 | } | |
645 | memcpy(new->key, key, key_size); | |
646 | new->sk = sk; | |
647 | new->hash = hash; | |
648 | return new; | |
649 | } | |
650 | ||
651 | static int sock_hash_update_common(struct bpf_map *map, void *key, | |
652 | struct sock *sk, u64 flags) | |
653 | { | |
654 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
655 | u32 key_size = map->key_size, hash; | |
656 | struct bpf_htab_elem *elem, *elem_new; | |
657 | struct bpf_htab_bucket *bucket; | |
658 | struct sk_psock_link *link; | |
659 | struct sk_psock *psock; | |
660 | int ret; | |
661 | ||
662 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
663 | if (unlikely(flags > BPF_EXIST)) | |
664 | return -EINVAL; | |
665 | ||
666 | link = sk_psock_init_link(); | |
667 | if (!link) | |
668 | return -ENOMEM; | |
669 | ||
670 | ret = sock_map_link(map, &htab->progs, sk); | |
671 | if (ret < 0) | |
672 | goto out_free; | |
673 | ||
674 | psock = sk_psock(sk); | |
675 | WARN_ON_ONCE(!psock); | |
676 | ||
677 | hash = sock_hash_bucket_hash(key, key_size); | |
678 | bucket = sock_hash_select_bucket(htab, hash); | |
679 | ||
680 | raw_spin_lock_bh(&bucket->lock); | |
681 | elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); | |
682 | if (elem && flags == BPF_NOEXIST) { | |
683 | ret = -EEXIST; | |
684 | goto out_unlock; | |
685 | } else if (!elem && flags == BPF_EXIST) { | |
686 | ret = -ENOENT; | |
687 | goto out_unlock; | |
688 | } | |
689 | ||
690 | elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem); | |
691 | if (IS_ERR(elem_new)) { | |
692 | ret = PTR_ERR(elem_new); | |
693 | goto out_unlock; | |
694 | } | |
695 | ||
696 | sock_map_add_link(psock, link, map, elem_new); | |
697 | /* Add new element to the head of the list, so that | |
698 | * concurrent search will find it before old elem. | |
699 | */ | |
700 | hlist_add_head_rcu(&elem_new->node, &bucket->head); | |
701 | if (elem) { | |
702 | hlist_del_rcu(&elem->node); | |
703 | sock_map_unref(elem->sk, elem); | |
704 | sock_hash_free_elem(htab, elem); | |
705 | } | |
706 | raw_spin_unlock_bh(&bucket->lock); | |
707 | return 0; | |
708 | out_unlock: | |
709 | raw_spin_unlock_bh(&bucket->lock); | |
710 | sk_psock_put(sk, psock); | |
711 | out_free: | |
712 | sk_psock_free_link(link); | |
713 | return ret; | |
714 | } | |
715 | ||
716 | static int sock_hash_update_elem(struct bpf_map *map, void *key, | |
717 | void *value, u64 flags) | |
718 | { | |
719 | u32 ufd = *(u32 *)value; | |
720 | struct socket *sock; | |
721 | struct sock *sk; | |
722 | int ret; | |
723 | ||
724 | sock = sockfd_lookup(ufd, &ret); | |
725 | if (!sock) | |
726 | return ret; | |
727 | sk = sock->sk; | |
728 | if (!sk) { | |
729 | ret = -EINVAL; | |
730 | goto out; | |
731 | } | |
732 | if (!sock_map_sk_is_suitable(sk) || | |
733 | sk->sk_state != TCP_ESTABLISHED) { | |
734 | ret = -EOPNOTSUPP; | |
735 | goto out; | |
736 | } | |
737 | ||
738 | sock_map_sk_acquire(sk); | |
739 | ret = sock_hash_update_common(map, key, sk, flags); | |
740 | sock_map_sk_release(sk); | |
741 | out: | |
742 | fput(sock->file); | |
743 | return ret; | |
744 | } | |
745 | ||
746 | static int sock_hash_get_next_key(struct bpf_map *map, void *key, | |
747 | void *key_next) | |
748 | { | |
749 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
750 | struct bpf_htab_elem *elem, *elem_next; | |
751 | u32 hash, key_size = map->key_size; | |
752 | struct hlist_head *head; | |
753 | int i = 0; | |
754 | ||
755 | if (!key) | |
756 | goto find_first_elem; | |
757 | hash = sock_hash_bucket_hash(key, key_size); | |
758 | head = &sock_hash_select_bucket(htab, hash)->head; | |
759 | elem = sock_hash_lookup_elem_raw(head, hash, key, key_size); | |
760 | if (!elem) | |
761 | goto find_first_elem; | |
762 | ||
763 | elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&elem->node)), | |
764 | struct bpf_htab_elem, node); | |
765 | if (elem_next) { | |
766 | memcpy(key_next, elem_next->key, key_size); | |
767 | return 0; | |
768 | } | |
769 | ||
770 | i = hash & (htab->buckets_num - 1); | |
771 | i++; | |
772 | find_first_elem: | |
773 | for (; i < htab->buckets_num; i++) { | |
774 | head = &sock_hash_select_bucket(htab, i)->head; | |
775 | elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)), | |
776 | struct bpf_htab_elem, node); | |
777 | if (elem_next) { | |
778 | memcpy(key_next, elem_next->key, key_size); | |
779 | return 0; | |
780 | } | |
781 | } | |
782 | ||
783 | return -ENOENT; | |
784 | } | |
785 | ||
786 | static struct bpf_map *sock_hash_alloc(union bpf_attr *attr) | |
787 | { | |
788 | struct bpf_htab *htab; | |
789 | int i, err; | |
790 | u64 cost; | |
791 | ||
792 | if (!capable(CAP_NET_ADMIN)) | |
793 | return ERR_PTR(-EPERM); | |
794 | if (attr->max_entries == 0 || | |
795 | attr->key_size == 0 || | |
796 | attr->value_size != 4 || | |
797 | attr->map_flags & ~SOCK_CREATE_FLAG_MASK) | |
798 | return ERR_PTR(-EINVAL); | |
799 | if (attr->key_size > MAX_BPF_STACK) | |
800 | return ERR_PTR(-E2BIG); | |
801 | ||
802 | htab = kzalloc(sizeof(*htab), GFP_USER); | |
803 | if (!htab) | |
804 | return ERR_PTR(-ENOMEM); | |
805 | ||
806 | bpf_map_init_from_attr(&htab->map, attr); | |
807 | ||
808 | htab->buckets_num = roundup_pow_of_two(htab->map.max_entries); | |
809 | htab->elem_size = sizeof(struct bpf_htab_elem) + | |
810 | round_up(htab->map.key_size, 8); | |
811 | if (htab->buckets_num == 0 || | |
812 | htab->buckets_num > U32_MAX / sizeof(struct bpf_htab_bucket)) { | |
813 | err = -EINVAL; | |
814 | goto free_htab; | |
815 | } | |
816 | ||
817 | cost = (u64) htab->buckets_num * sizeof(struct bpf_htab_bucket) + | |
818 | (u64) htab->elem_size * htab->map.max_entries; | |
819 | if (cost >= U32_MAX - PAGE_SIZE) { | |
820 | err = -EINVAL; | |
821 | goto free_htab; | |
822 | } | |
823 | ||
824 | htab->buckets = bpf_map_area_alloc(htab->buckets_num * | |
825 | sizeof(struct bpf_htab_bucket), | |
826 | htab->map.numa_node); | |
827 | if (!htab->buckets) { | |
828 | err = -ENOMEM; | |
829 | goto free_htab; | |
830 | } | |
831 | ||
832 | for (i = 0; i < htab->buckets_num; i++) { | |
833 | INIT_HLIST_HEAD(&htab->buckets[i].head); | |
834 | raw_spin_lock_init(&htab->buckets[i].lock); | |
835 | } | |
836 | ||
837 | return &htab->map; | |
838 | free_htab: | |
839 | kfree(htab); | |
840 | return ERR_PTR(err); | |
841 | } | |
842 | ||
843 | static void sock_hash_free(struct bpf_map *map) | |
844 | { | |
845 | struct bpf_htab *htab = container_of(map, struct bpf_htab, map); | |
846 | struct bpf_htab_bucket *bucket; | |
847 | struct bpf_htab_elem *elem; | |
848 | struct hlist_node *node; | |
849 | int i; | |
850 | ||
851 | synchronize_rcu(); | |
852 | rcu_read_lock(); | |
853 | for (i = 0; i < htab->buckets_num; i++) { | |
854 | bucket = sock_hash_select_bucket(htab, i); | |
855 | raw_spin_lock_bh(&bucket->lock); | |
856 | hlist_for_each_entry_safe(elem, node, &bucket->head, node) { | |
857 | hlist_del_rcu(&elem->node); | |
858 | sock_map_unref(elem->sk, elem); | |
859 | } | |
860 | raw_spin_unlock_bh(&bucket->lock); | |
861 | } | |
862 | rcu_read_unlock(); | |
863 | ||
864 | bpf_map_area_free(htab->buckets); | |
865 | kfree(htab); | |
866 | } | |
867 | ||
868 | static void sock_hash_release_progs(struct bpf_map *map) | |
869 | { | |
870 | psock_progs_drop(&container_of(map, struct bpf_htab, map)->progs); | |
871 | } | |
872 | ||
873 | BPF_CALL_4(bpf_sock_hash_update, struct bpf_sock_ops_kern *, sops, | |
874 | struct bpf_map *, map, void *, key, u64, flags) | |
875 | { | |
876 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
877 | ||
878 | if (likely(sock_map_sk_is_suitable(sops->sk) && | |
879 | sock_map_op_okay(sops))) | |
880 | return sock_hash_update_common(map, key, sops->sk, flags); | |
881 | return -EOPNOTSUPP; | |
882 | } | |
883 | ||
884 | const struct bpf_func_proto bpf_sock_hash_update_proto = { | |
885 | .func = bpf_sock_hash_update, | |
886 | .gpl_only = false, | |
887 | .pkt_access = true, | |
888 | .ret_type = RET_INTEGER, | |
889 | .arg1_type = ARG_PTR_TO_CTX, | |
890 | .arg2_type = ARG_CONST_MAP_PTR, | |
891 | .arg3_type = ARG_PTR_TO_MAP_KEY, | |
892 | .arg4_type = ARG_ANYTHING, | |
893 | }; | |
894 | ||
895 | BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb, | |
896 | struct bpf_map *, map, void *, key, u64, flags) | |
897 | { | |
898 | struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); | |
899 | ||
900 | if (unlikely(flags & ~(BPF_F_INGRESS))) | |
901 | return SK_DROP; | |
902 | tcb->bpf.flags = flags; | |
903 | tcb->bpf.sk_redir = __sock_hash_lookup_elem(map, key); | |
904 | if (!tcb->bpf.sk_redir) | |
905 | return SK_DROP; | |
906 | return SK_PASS; | |
907 | } | |
908 | ||
909 | const struct bpf_func_proto bpf_sk_redirect_hash_proto = { | |
910 | .func = bpf_sk_redirect_hash, | |
911 | .gpl_only = false, | |
912 | .ret_type = RET_INTEGER, | |
913 | .arg1_type = ARG_PTR_TO_CTX, | |
914 | .arg2_type = ARG_CONST_MAP_PTR, | |
915 | .arg3_type = ARG_PTR_TO_MAP_KEY, | |
916 | .arg4_type = ARG_ANYTHING, | |
917 | }; | |
918 | ||
919 | BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg, | |
920 | struct bpf_map *, map, void *, key, u64, flags) | |
921 | { | |
922 | if (unlikely(flags & ~(BPF_F_INGRESS))) | |
923 | return SK_DROP; | |
924 | msg->flags = flags; | |
925 | msg->sk_redir = __sock_hash_lookup_elem(map, key); | |
926 | if (!msg->sk_redir) | |
927 | return SK_DROP; | |
928 | return SK_PASS; | |
929 | } | |
930 | ||
931 | const struct bpf_func_proto bpf_msg_redirect_hash_proto = { | |
932 | .func = bpf_msg_redirect_hash, | |
933 | .gpl_only = false, | |
934 | .ret_type = RET_INTEGER, | |
935 | .arg1_type = ARG_PTR_TO_CTX, | |
936 | .arg2_type = ARG_CONST_MAP_PTR, | |
937 | .arg3_type = ARG_PTR_TO_MAP_KEY, | |
938 | .arg4_type = ARG_ANYTHING, | |
939 | }; | |
940 | ||
941 | const struct bpf_map_ops sock_hash_ops = { | |
942 | .map_alloc = sock_hash_alloc, | |
943 | .map_free = sock_hash_free, | |
944 | .map_get_next_key = sock_hash_get_next_key, | |
945 | .map_update_elem = sock_hash_update_elem, | |
946 | .map_delete_elem = sock_hash_delete_elem, | |
947 | .map_lookup_elem = sock_map_lookup, | |
948 | .map_release_uref = sock_hash_release_progs, | |
949 | .map_check_btf = map_check_no_btf, | |
950 | }; | |
951 | ||
952 | static struct sk_psock_progs *sock_map_progs(struct bpf_map *map) | |
953 | { | |
954 | switch (map->map_type) { | |
955 | case BPF_MAP_TYPE_SOCKMAP: | |
956 | return &container_of(map, struct bpf_stab, map)->progs; | |
957 | case BPF_MAP_TYPE_SOCKHASH: | |
958 | return &container_of(map, struct bpf_htab, map)->progs; | |
959 | default: | |
960 | break; | |
961 | } | |
962 | ||
963 | return NULL; | |
964 | } | |
965 | ||
966 | int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog, | |
967 | u32 which) | |
968 | { | |
969 | struct sk_psock_progs *progs = sock_map_progs(map); | |
970 | ||
971 | if (!progs) | |
972 | return -EOPNOTSUPP; | |
973 | ||
974 | switch (which) { | |
975 | case BPF_SK_MSG_VERDICT: | |
976 | psock_set_prog(&progs->msg_parser, prog); | |
977 | break; | |
978 | case BPF_SK_SKB_STREAM_PARSER: | |
979 | psock_set_prog(&progs->skb_parser, prog); | |
980 | break; | |
981 | case BPF_SK_SKB_STREAM_VERDICT: | |
982 | psock_set_prog(&progs->skb_verdict, prog); | |
983 | break; | |
984 | default: | |
985 | return -EOPNOTSUPP; | |
986 | } | |
987 | ||
988 | return 0; | |
989 | } | |
990 | ||
991 | void sk_psock_unlink(struct sock *sk, struct sk_psock_link *link) | |
992 | { | |
993 | switch (link->map->map_type) { | |
994 | case BPF_MAP_TYPE_SOCKMAP: | |
995 | return sock_map_delete_from_link(link->map, sk, | |
996 | link->link_raw); | |
997 | case BPF_MAP_TYPE_SOCKHASH: | |
998 | return sock_hash_delete_from_link(link->map, sk, | |
999 | link->link_raw); | |
1000 | default: | |
1001 | break; | |
1002 | } | |
1003 | } |