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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#include <linux/sock_diag.h>
14#include <net/udp.h>
15
16struct bpf_stab {
17 struct bpf_map map;
18 struct sock **sks;
19 struct sk_psock_progs progs;
20 raw_spinlock_t lock;
21};
22
23#define SOCK_CREATE_FLAG_MASK \
24 (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
25
26static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
27{
28 struct bpf_stab *stab;
29 u64 cost;
30 int err;
31
32 if (!capable(CAP_NET_ADMIN))
33 return ERR_PTR(-EPERM);
34 if (attr->max_entries == 0 ||
35 attr->key_size != 4 ||
36 (attr->value_size != sizeof(u32) &&
37 attr->value_size != sizeof(u64)) ||
38 attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
39 return ERR_PTR(-EINVAL);
40
41 stab = kzalloc(sizeof(*stab), GFP_USER);
42 if (!stab)
43 return ERR_PTR(-ENOMEM);
44
45 bpf_map_init_from_attr(&stab->map, attr);
46 raw_spin_lock_init(&stab->lock);
47
48 /* Make sure page count doesn't overflow. */
49 cost = (u64) stab->map.max_entries * sizeof(struct sock *);
50 err = bpf_map_charge_init(&stab->map.memory, cost);
51 if (err)
52 goto free_stab;
53
54 stab->sks = bpf_map_area_alloc(stab->map.max_entries *
55 sizeof(struct sock *),
56 stab->map.numa_node);
57 if (stab->sks)
58 return &stab->map;
59 err = -ENOMEM;
60 bpf_map_charge_finish(&stab->map.memory);
61free_stab:
62 kfree(stab);
63 return ERR_PTR(err);
64}
65
66int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog)
67{
68 u32 ufd = attr->target_fd;
69 struct bpf_map *map;
70 struct fd f;
71 int ret;
72
73 if (attr->attach_flags || attr->replace_bpf_fd)
74 return -EINVAL;
75
76 f = fdget(ufd);
77 map = __bpf_map_get(f);
78 if (IS_ERR(map))
79 return PTR_ERR(map);
80 ret = sock_map_prog_update(map, prog, NULL, attr->attach_type);
81 fdput(f);
82 return ret;
83}
84
85int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype)
86{
87 u32 ufd = attr->target_fd;
88 struct bpf_prog *prog;
89 struct bpf_map *map;
90 struct fd f;
91 int ret;
92
93 if (attr->attach_flags || attr->replace_bpf_fd)
94 return -EINVAL;
95
96 f = fdget(ufd);
97 map = __bpf_map_get(f);
98 if (IS_ERR(map))
99 return PTR_ERR(map);
100
101 prog = bpf_prog_get(attr->attach_bpf_fd);
102 if (IS_ERR(prog)) {
103 ret = PTR_ERR(prog);
104 goto put_map;
105 }
106
107 if (prog->type != ptype) {
108 ret = -EINVAL;
109 goto put_prog;
110 }
111
112 ret = sock_map_prog_update(map, NULL, prog, attr->attach_type);
113put_prog:
114 bpf_prog_put(prog);
115put_map:
116 fdput(f);
117 return ret;
118}
119
120static void sock_map_sk_acquire(struct sock *sk)
121 __acquires(&sk->sk_lock.slock)
122{
123 lock_sock(sk);
124 preempt_disable();
125 rcu_read_lock();
126}
127
128static void sock_map_sk_release(struct sock *sk)
129 __releases(&sk->sk_lock.slock)
130{
131 rcu_read_unlock();
132 preempt_enable();
133 release_sock(sk);
134}
135
136static void sock_map_add_link(struct sk_psock *psock,
137 struct sk_psock_link *link,
138 struct bpf_map *map, void *link_raw)
139{
140 link->link_raw = link_raw;
141 link->map = map;
142 spin_lock_bh(&psock->link_lock);
143 list_add_tail(&link->list, &psock->link);
144 spin_unlock_bh(&psock->link_lock);
145}
146
147static void sock_map_del_link(struct sock *sk,
148 struct sk_psock *psock, void *link_raw)
149{
150 struct sk_psock_link *link, *tmp;
151 bool strp_stop = false;
152
153 spin_lock_bh(&psock->link_lock);
154 list_for_each_entry_safe(link, tmp, &psock->link, list) {
155 if (link->link_raw == link_raw) {
156 struct bpf_map *map = link->map;
157 struct bpf_stab *stab = container_of(map, struct bpf_stab,
158 map);
159 if (psock->parser.enabled && stab->progs.skb_parser)
160 strp_stop = true;
161 list_del(&link->list);
162 sk_psock_free_link(link);
163 }
164 }
165 spin_unlock_bh(&psock->link_lock);
166 if (strp_stop) {
167 write_lock_bh(&sk->sk_callback_lock);
168 sk_psock_stop_strp(sk, psock);
169 write_unlock_bh(&sk->sk_callback_lock);
170 }
171}
172
173static void sock_map_unref(struct sock *sk, void *link_raw)
174{
175 struct sk_psock *psock = sk_psock(sk);
176
177 if (likely(psock)) {
178 sock_map_del_link(sk, psock, link_raw);
179 sk_psock_put(sk, psock);
180 }
181}
182
183static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
184{
185 struct proto *prot;
186
187 sock_owned_by_me(sk);
188
189 switch (sk->sk_type) {
190 case SOCK_STREAM:
191 prot = tcp_bpf_get_proto(sk, psock);
192 break;
193
194 case SOCK_DGRAM:
195 prot = udp_bpf_get_proto(sk, psock);
196 break;
197
198 default:
199 return -EINVAL;
200 }
201
202 if (IS_ERR(prot))
203 return PTR_ERR(prot);
204
205 sk_psock_update_proto(sk, psock, prot);
206 return 0;
207}
208
209static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
210{
211 struct sk_psock *psock;
212
213 rcu_read_lock();
214 psock = sk_psock(sk);
215 if (psock) {
216 if (sk->sk_prot->close != sock_map_close) {
217 psock = ERR_PTR(-EBUSY);
218 goto out;
219 }
220
221 if (!refcount_inc_not_zero(&psock->refcnt))
222 psock = ERR_PTR(-EBUSY);
223 }
224out:
225 rcu_read_unlock();
226 return psock;
227}
228
229static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
230 struct sock *sk)
231{
232 struct bpf_prog *msg_parser, *skb_parser, *skb_verdict;
233 struct sk_psock *psock;
234 bool skb_progs;
235 int ret;
236
237 skb_verdict = READ_ONCE(progs->skb_verdict);
238 skb_parser = READ_ONCE(progs->skb_parser);
239 skb_progs = skb_parser && skb_verdict;
240 if (skb_progs) {
241 skb_verdict = bpf_prog_inc_not_zero(skb_verdict);
242 if (IS_ERR(skb_verdict))
243 return PTR_ERR(skb_verdict);
244 skb_parser = bpf_prog_inc_not_zero(skb_parser);
245 if (IS_ERR(skb_parser)) {
246 bpf_prog_put(skb_verdict);
247 return PTR_ERR(skb_parser);
248 }
249 }
250
251 msg_parser = READ_ONCE(progs->msg_parser);
252 if (msg_parser) {
253 msg_parser = bpf_prog_inc_not_zero(msg_parser);
254 if (IS_ERR(msg_parser)) {
255 ret = PTR_ERR(msg_parser);
256 goto out;
257 }
258 }
259
260 psock = sock_map_psock_get_checked(sk);
261 if (IS_ERR(psock)) {
262 ret = PTR_ERR(psock);
263 goto out_progs;
264 }
265
266 if (psock) {
267 if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||
268 (skb_progs && READ_ONCE(psock->progs.skb_parser))) {
269 sk_psock_put(sk, psock);
270 ret = -EBUSY;
271 goto out_progs;
272 }
273 } else {
274 psock = sk_psock_init(sk, map->numa_node);
275 if (!psock) {
276 ret = -ENOMEM;
277 goto out_progs;
278 }
279 }
280
281 if (msg_parser)
282 psock_set_prog(&psock->progs.msg_parser, msg_parser);
283
284 ret = sock_map_init_proto(sk, psock);
285 if (ret < 0)
286 goto out_drop;
287
288 write_lock_bh(&sk->sk_callback_lock);
289 if (skb_progs && !psock->parser.enabled) {
290 ret = sk_psock_init_strp(sk, psock);
291 if (ret) {
292 write_unlock_bh(&sk->sk_callback_lock);
293 goto out_drop;
294 }
295 psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
296 psock_set_prog(&psock->progs.skb_parser, skb_parser);
297 sk_psock_start_strp(sk, psock);
298 }
299 write_unlock_bh(&sk->sk_callback_lock);
300 return 0;
301out_drop:
302 sk_psock_put(sk, psock);
303out_progs:
304 if (msg_parser)
305 bpf_prog_put(msg_parser);
306out:
307 if (skb_progs) {
308 bpf_prog_put(skb_verdict);
309 bpf_prog_put(skb_parser);
310 }
311 return ret;
312}
313
314static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk)
315{
316 struct sk_psock *psock;
317 int ret;
318
319 psock = sock_map_psock_get_checked(sk);
320 if (IS_ERR(psock))
321 return PTR_ERR(psock);
322
323 if (!psock) {
324 psock = sk_psock_init(sk, map->numa_node);
325 if (!psock)
326 return -ENOMEM;
327 }
328
329 ret = sock_map_init_proto(sk, psock);
330 if (ret < 0)
331 sk_psock_put(sk, psock);
332 return ret;
333}
334
335static void sock_map_free(struct bpf_map *map)
336{
337 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
338 int i;
339
340 /* After the sync no updates or deletes will be in-flight so it
341 * is safe to walk map and remove entries without risking a race
342 * in EEXIST update case.
343 */
344 synchronize_rcu();
345 for (i = 0; i < stab->map.max_entries; i++) {
346 struct sock **psk = &stab->sks[i];
347 struct sock *sk;
348
349 sk = xchg(psk, NULL);
350 if (sk) {
351 lock_sock(sk);
352 rcu_read_lock();
353 sock_map_unref(sk, psk);
354 rcu_read_unlock();
355 release_sock(sk);
356 }
357 }
358
359 /* wait for psock readers accessing its map link */
360 synchronize_rcu();
361
362 bpf_map_area_free(stab->sks);
363 kfree(stab);
364}
365
366static void sock_map_release_progs(struct bpf_map *map)
367{
368 psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs);
369}
370
371static struct sock *__sock_map_lookup_elem(struct bpf_map *map, u32 key)
372{
373 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
374
375 WARN_ON_ONCE(!rcu_read_lock_held());
376
377 if (unlikely(key >= map->max_entries))
378 return NULL;
379 return READ_ONCE(stab->sks[key]);
380}
381
382static void *sock_map_lookup(struct bpf_map *map, void *key)
383{
384 struct sock *sk;
385
386 sk = __sock_map_lookup_elem(map, *(u32 *)key);
387 if (!sk || !sk_fullsock(sk))
388 return NULL;
389 if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
390 return NULL;
391 return sk;
392}
393
394static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
395{
396 struct sock *sk;
397
398 if (map->value_size != sizeof(u64))
399 return ERR_PTR(-ENOSPC);
400
401 sk = __sock_map_lookup_elem(map, *(u32 *)key);
402 if (!sk)
403 return ERR_PTR(-ENOENT);
404
405 sock_gen_cookie(sk);
406 return &sk->sk_cookie;
407}
408
409static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
410 struct sock **psk)
411{
412 struct sock *sk;
413 int err = 0;
414
415 raw_spin_lock_bh(&stab->lock);
416 sk = *psk;
417 if (!sk_test || sk_test == sk)
418 sk = xchg(psk, NULL);
419
420 if (likely(sk))
421 sock_map_unref(sk, psk);
422 else
423 err = -EINVAL;
424
425 raw_spin_unlock_bh(&stab->lock);
426 return err;
427}
428
429static void sock_map_delete_from_link(struct bpf_map *map, struct sock *sk,
430 void *link_raw)
431{
432 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
433
434 __sock_map_delete(stab, sk, link_raw);
435}
436
437static int sock_map_delete_elem(struct bpf_map *map, void *key)
438{
439 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
440 u32 i = *(u32 *)key;
441 struct sock **psk;
442
443 if (unlikely(i >= map->max_entries))
444 return -EINVAL;
445
446 psk = &stab->sks[i];
447 return __sock_map_delete(stab, NULL, psk);
448}
449
450static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
451{
452 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
453 u32 i = key ? *(u32 *)key : U32_MAX;
454 u32 *key_next = next;
455
456 if (i == stab->map.max_entries - 1)
457 return -ENOENT;
458 if (i >= stab->map.max_entries)
459 *key_next = 0;
460 else
461 *key_next = i + 1;
462 return 0;
463}
464
465static bool sock_map_redirect_allowed(const struct sock *sk);
466
467static int sock_map_update_common(struct bpf_map *map, u32 idx,
468 struct sock *sk, u64 flags)
469{
470 struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
471 struct sk_psock_link *link;
472 struct sk_psock *psock;
473 struct sock *osk;
474 int ret;
475
476 WARN_ON_ONCE(!rcu_read_lock_held());
477 if (unlikely(flags > BPF_EXIST))
478 return -EINVAL;
479 if (unlikely(idx >= map->max_entries))
480 return -E2BIG;
481 if (inet_csk_has_ulp(sk))
482 return -EINVAL;
483
484 link = sk_psock_init_link();
485 if (!link)
486 return -ENOMEM;
487
488 /* Only sockets we can redirect into/from in BPF need to hold
489 * refs to parser/verdict progs and have their sk_data_ready
490 * and sk_write_space callbacks overridden.
491 */
492 if (sock_map_redirect_allowed(sk))
493 ret = sock_map_link(map, &stab->progs, sk);
494 else
495 ret = sock_map_link_no_progs(map, sk);
496 if (ret < 0)
497 goto out_free;
498
499 psock = sk_psock(sk);
500 WARN_ON_ONCE(!psock);
501
502 raw_spin_lock_bh(&stab->lock);
503 osk = stab->sks[idx];
504 if (osk && flags == BPF_NOEXIST) {
505 ret = -EEXIST;
506 goto out_unlock;
507 } else if (!osk && flags == BPF_EXIST) {
508 ret = -ENOENT;
509 goto out_unlock;
510 }
511
512 sock_map_add_link(psock, link, map, &stab->sks[idx]);
513 stab->sks[idx] = sk;
514 if (osk)
515 sock_map_unref(osk, &stab->sks[idx]);
516 raw_spin_unlock_bh(&stab->lock);
517 return 0;
518out_unlock:
519 raw_spin_unlock_bh(&stab->lock);
520 if (psock)
521 sk_psock_put(sk, psock);
522out_free:
523 sk_psock_free_link(link);
524 return ret;
525}
526
527static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
528{
529 return ops->op == BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB ||
530 ops->op == BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB ||
531 ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB;
532}
533
534static bool sk_is_tcp(const struct sock *sk)
535{
536 return sk->sk_type == SOCK_STREAM &&
537 sk->sk_protocol == IPPROTO_TCP;
538}
539
540static bool sk_is_udp(const struct sock *sk)
541{
542 return sk->sk_type == SOCK_DGRAM &&
543 sk->sk_protocol == IPPROTO_UDP;
544}
545
546static bool sock_map_redirect_allowed(const struct sock *sk)
547{
548 return sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN;
549}
550
551static bool sock_map_sk_is_suitable(const struct sock *sk)
552{
553 return sk_is_tcp(sk) || sk_is_udp(sk);
554}
555
556static bool sock_map_sk_state_allowed(const struct sock *sk)
557{
558 if (sk_is_tcp(sk))
559 return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
560 else if (sk_is_udp(sk))
561 return sk_hashed(sk);
562
563 return false;
564}
565
566static int sock_map_update_elem(struct bpf_map *map, void *key,
567 void *value, u64 flags)
568{
569 u32 idx = *(u32 *)key;
570 struct socket *sock;
571 struct sock *sk;
572 int ret;
573 u64 ufd;
574
575 if (map->value_size == sizeof(u64))
576 ufd = *(u64 *)value;
577 else
578 ufd = *(u32 *)value;
579 if (ufd > S32_MAX)
580 return -EINVAL;
581
582 sock = sockfd_lookup(ufd, &ret);
583 if (!sock)
584 return ret;
585 sk = sock->sk;
586 if (!sk) {
587 ret = -EINVAL;
588 goto out;
589 }
590 if (!sock_map_sk_is_suitable(sk)) {
591 ret = -EOPNOTSUPP;
592 goto out;
593 }
594
595 sock_map_sk_acquire(sk);
596 if (!sock_map_sk_state_allowed(sk))
597 ret = -EOPNOTSUPP;
598 else
599 ret = sock_map_update_common(map, idx, sk, flags);
600 sock_map_sk_release(sk);
601out:
602 fput(sock->file);
603 return ret;
604}
605
606BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, sops,
607 struct bpf_map *, map, void *, key, u64, flags)
608{
609 WARN_ON_ONCE(!rcu_read_lock_held());
610
611 if (likely(sock_map_sk_is_suitable(sops->sk) &&
612 sock_map_op_okay(sops)))
613 return sock_map_update_common(map, *(u32 *)key, sops->sk,
614 flags);
615 return -EOPNOTSUPP;
616}
617
618const struct bpf_func_proto bpf_sock_map_update_proto = {
619 .func = bpf_sock_map_update,
620 .gpl_only = false,
621 .pkt_access = true,
622 .ret_type = RET_INTEGER,
623 .arg1_type = ARG_PTR_TO_CTX,
624 .arg2_type = ARG_CONST_MAP_PTR,
625 .arg3_type = ARG_PTR_TO_MAP_KEY,
626 .arg4_type = ARG_ANYTHING,
627};
628
629BPF_CALL_4(bpf_sk_redirect_map, struct sk_buff *, skb,
630 struct bpf_map *, map, u32, key, u64, flags)
631{
632 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
633 struct sock *sk;
634
635 if (unlikely(flags & ~(BPF_F_INGRESS)))
636 return SK_DROP;
637
638 sk = __sock_map_lookup_elem(map, key);
639 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
640 return SK_DROP;
641
642 tcb->bpf.flags = flags;
643 tcb->bpf.sk_redir = sk;
644 return SK_PASS;
645}
646
647const struct bpf_func_proto bpf_sk_redirect_map_proto = {
648 .func = bpf_sk_redirect_map,
649 .gpl_only = false,
650 .ret_type = RET_INTEGER,
651 .arg1_type = ARG_PTR_TO_CTX,
652 .arg2_type = ARG_CONST_MAP_PTR,
653 .arg3_type = ARG_ANYTHING,
654 .arg4_type = ARG_ANYTHING,
655};
656
657BPF_CALL_4(bpf_msg_redirect_map, struct sk_msg *, msg,
658 struct bpf_map *, map, u32, key, u64, flags)
659{
660 struct sock *sk;
661
662 if (unlikely(flags & ~(BPF_F_INGRESS)))
663 return SK_DROP;
664
665 sk = __sock_map_lookup_elem(map, key);
666 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
667 return SK_DROP;
668
669 msg->flags = flags;
670 msg->sk_redir = sk;
671 return SK_PASS;
672}
673
674const struct bpf_func_proto bpf_msg_redirect_map_proto = {
675 .func = bpf_msg_redirect_map,
676 .gpl_only = false,
677 .ret_type = RET_INTEGER,
678 .arg1_type = ARG_PTR_TO_CTX,
679 .arg2_type = ARG_CONST_MAP_PTR,
680 .arg3_type = ARG_ANYTHING,
681 .arg4_type = ARG_ANYTHING,
682};
683
684static int sock_map_btf_id;
685const struct bpf_map_ops sock_map_ops = {
686 .map_alloc = sock_map_alloc,
687 .map_free = sock_map_free,
688 .map_get_next_key = sock_map_get_next_key,
689 .map_lookup_elem_sys_only = sock_map_lookup_sys,
690 .map_update_elem = sock_map_update_elem,
691 .map_delete_elem = sock_map_delete_elem,
692 .map_lookup_elem = sock_map_lookup,
693 .map_release_uref = sock_map_release_progs,
694 .map_check_btf = map_check_no_btf,
695 .map_btf_name = "bpf_stab",
696 .map_btf_id = &sock_map_btf_id,
697};
698
699struct bpf_shtab_elem {
700 struct rcu_head rcu;
701 u32 hash;
702 struct sock *sk;
703 struct hlist_node node;
704 u8 key[];
705};
706
707struct bpf_shtab_bucket {
708 struct hlist_head head;
709 raw_spinlock_t lock;
710};
711
712struct bpf_shtab {
713 struct bpf_map map;
714 struct bpf_shtab_bucket *buckets;
715 u32 buckets_num;
716 u32 elem_size;
717 struct sk_psock_progs progs;
718 atomic_t count;
719};
720
721static inline u32 sock_hash_bucket_hash(const void *key, u32 len)
722{
723 return jhash(key, len, 0);
724}
725
726static struct bpf_shtab_bucket *sock_hash_select_bucket(struct bpf_shtab *htab,
727 u32 hash)
728{
729 return &htab->buckets[hash & (htab->buckets_num - 1)];
730}
731
732static struct bpf_shtab_elem *
733sock_hash_lookup_elem_raw(struct hlist_head *head, u32 hash, void *key,
734 u32 key_size)
735{
736 struct bpf_shtab_elem *elem;
737
738 hlist_for_each_entry_rcu(elem, head, node) {
739 if (elem->hash == hash &&
740 !memcmp(&elem->key, key, key_size))
741 return elem;
742 }
743
744 return NULL;
745}
746
747static struct sock *__sock_hash_lookup_elem(struct bpf_map *map, void *key)
748{
749 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
750 u32 key_size = map->key_size, hash;
751 struct bpf_shtab_bucket *bucket;
752 struct bpf_shtab_elem *elem;
753
754 WARN_ON_ONCE(!rcu_read_lock_held());
755
756 hash = sock_hash_bucket_hash(key, key_size);
757 bucket = sock_hash_select_bucket(htab, hash);
758 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
759
760 return elem ? elem->sk : NULL;
761}
762
763static void sock_hash_free_elem(struct bpf_shtab *htab,
764 struct bpf_shtab_elem *elem)
765{
766 atomic_dec(&htab->count);
767 kfree_rcu(elem, rcu);
768}
769
770static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,
771 void *link_raw)
772{
773 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
774 struct bpf_shtab_elem *elem_probe, *elem = link_raw;
775 struct bpf_shtab_bucket *bucket;
776
777 WARN_ON_ONCE(!rcu_read_lock_held());
778 bucket = sock_hash_select_bucket(htab, elem->hash);
779
780 /* elem may be deleted in parallel from the map, but access here
781 * is okay since it's going away only after RCU grace period.
782 * However, we need to check whether it's still present.
783 */
784 raw_spin_lock_bh(&bucket->lock);
785 elem_probe = sock_hash_lookup_elem_raw(&bucket->head, elem->hash,
786 elem->key, map->key_size);
787 if (elem_probe && elem_probe == elem) {
788 hlist_del_rcu(&elem->node);
789 sock_map_unref(elem->sk, elem);
790 sock_hash_free_elem(htab, elem);
791 }
792 raw_spin_unlock_bh(&bucket->lock);
793}
794
795static int sock_hash_delete_elem(struct bpf_map *map, void *key)
796{
797 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
798 u32 hash, key_size = map->key_size;
799 struct bpf_shtab_bucket *bucket;
800 struct bpf_shtab_elem *elem;
801 int ret = -ENOENT;
802
803 hash = sock_hash_bucket_hash(key, key_size);
804 bucket = sock_hash_select_bucket(htab, hash);
805
806 raw_spin_lock_bh(&bucket->lock);
807 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
808 if (elem) {
809 hlist_del_rcu(&elem->node);
810 sock_map_unref(elem->sk, elem);
811 sock_hash_free_elem(htab, elem);
812 ret = 0;
813 }
814 raw_spin_unlock_bh(&bucket->lock);
815 return ret;
816}
817
818static struct bpf_shtab_elem *sock_hash_alloc_elem(struct bpf_shtab *htab,
819 void *key, u32 key_size,
820 u32 hash, struct sock *sk,
821 struct bpf_shtab_elem *old)
822{
823 struct bpf_shtab_elem *new;
824
825 if (atomic_inc_return(&htab->count) > htab->map.max_entries) {
826 if (!old) {
827 atomic_dec(&htab->count);
828 return ERR_PTR(-E2BIG);
829 }
830 }
831
832 new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN,
833 htab->map.numa_node);
834 if (!new) {
835 atomic_dec(&htab->count);
836 return ERR_PTR(-ENOMEM);
837 }
838 memcpy(new->key, key, key_size);
839 new->sk = sk;
840 new->hash = hash;
841 return new;
842}
843
844static int sock_hash_update_common(struct bpf_map *map, void *key,
845 struct sock *sk, u64 flags)
846{
847 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
848 u32 key_size = map->key_size, hash;
849 struct bpf_shtab_elem *elem, *elem_new;
850 struct bpf_shtab_bucket *bucket;
851 struct sk_psock_link *link;
852 struct sk_psock *psock;
853 int ret;
854
855 WARN_ON_ONCE(!rcu_read_lock_held());
856 if (unlikely(flags > BPF_EXIST))
857 return -EINVAL;
858 if (inet_csk_has_ulp(sk))
859 return -EINVAL;
860
861 link = sk_psock_init_link();
862 if (!link)
863 return -ENOMEM;
864
865 /* Only sockets we can redirect into/from in BPF need to hold
866 * refs to parser/verdict progs and have their sk_data_ready
867 * and sk_write_space callbacks overridden.
868 */
869 if (sock_map_redirect_allowed(sk))
870 ret = sock_map_link(map, &htab->progs, sk);
871 else
872 ret = sock_map_link_no_progs(map, sk);
873 if (ret < 0)
874 goto out_free;
875
876 psock = sk_psock(sk);
877 WARN_ON_ONCE(!psock);
878
879 hash = sock_hash_bucket_hash(key, key_size);
880 bucket = sock_hash_select_bucket(htab, hash);
881
882 raw_spin_lock_bh(&bucket->lock);
883 elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size);
884 if (elem && flags == BPF_NOEXIST) {
885 ret = -EEXIST;
886 goto out_unlock;
887 } else if (!elem && flags == BPF_EXIST) {
888 ret = -ENOENT;
889 goto out_unlock;
890 }
891
892 elem_new = sock_hash_alloc_elem(htab, key, key_size, hash, sk, elem);
893 if (IS_ERR(elem_new)) {
894 ret = PTR_ERR(elem_new);
895 goto out_unlock;
896 }
897
898 sock_map_add_link(psock, link, map, elem_new);
899 /* Add new element to the head of the list, so that
900 * concurrent search will find it before old elem.
901 */
902 hlist_add_head_rcu(&elem_new->node, &bucket->head);
903 if (elem) {
904 hlist_del_rcu(&elem->node);
905 sock_map_unref(elem->sk, elem);
906 sock_hash_free_elem(htab, elem);
907 }
908 raw_spin_unlock_bh(&bucket->lock);
909 return 0;
910out_unlock:
911 raw_spin_unlock_bh(&bucket->lock);
912 sk_psock_put(sk, psock);
913out_free:
914 sk_psock_free_link(link);
915 return ret;
916}
917
918static int sock_hash_update_elem(struct bpf_map *map, void *key,
919 void *value, u64 flags)
920{
921 struct socket *sock;
922 struct sock *sk;
923 int ret;
924 u64 ufd;
925
926 if (map->value_size == sizeof(u64))
927 ufd = *(u64 *)value;
928 else
929 ufd = *(u32 *)value;
930 if (ufd > S32_MAX)
931 return -EINVAL;
932
933 sock = sockfd_lookup(ufd, &ret);
934 if (!sock)
935 return ret;
936 sk = sock->sk;
937 if (!sk) {
938 ret = -EINVAL;
939 goto out;
940 }
941 if (!sock_map_sk_is_suitable(sk)) {
942 ret = -EOPNOTSUPP;
943 goto out;
944 }
945
946 sock_map_sk_acquire(sk);
947 if (!sock_map_sk_state_allowed(sk))
948 ret = -EOPNOTSUPP;
949 else
950 ret = sock_hash_update_common(map, key, sk, flags);
951 sock_map_sk_release(sk);
952out:
953 fput(sock->file);
954 return ret;
955}
956
957static int sock_hash_get_next_key(struct bpf_map *map, void *key,
958 void *key_next)
959{
960 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
961 struct bpf_shtab_elem *elem, *elem_next;
962 u32 hash, key_size = map->key_size;
963 struct hlist_head *head;
964 int i = 0;
965
966 if (!key)
967 goto find_first_elem;
968 hash = sock_hash_bucket_hash(key, key_size);
969 head = &sock_hash_select_bucket(htab, hash)->head;
970 elem = sock_hash_lookup_elem_raw(head, hash, key, key_size);
971 if (!elem)
972 goto find_first_elem;
973
974 elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&elem->node)),
975 struct bpf_shtab_elem, node);
976 if (elem_next) {
977 memcpy(key_next, elem_next->key, key_size);
978 return 0;
979 }
980
981 i = hash & (htab->buckets_num - 1);
982 i++;
983find_first_elem:
984 for (; i < htab->buckets_num; i++) {
985 head = &sock_hash_select_bucket(htab, i)->head;
986 elem_next = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
987 struct bpf_shtab_elem, node);
988 if (elem_next) {
989 memcpy(key_next, elem_next->key, key_size);
990 return 0;
991 }
992 }
993
994 return -ENOENT;
995}
996
997static struct bpf_map *sock_hash_alloc(union bpf_attr *attr)
998{
999 struct bpf_shtab *htab;
1000 int i, err;
1001 u64 cost;
1002
1003 if (!capable(CAP_NET_ADMIN))
1004 return ERR_PTR(-EPERM);
1005 if (attr->max_entries == 0 ||
1006 attr->key_size == 0 ||
1007 (attr->value_size != sizeof(u32) &&
1008 attr->value_size != sizeof(u64)) ||
1009 attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
1010 return ERR_PTR(-EINVAL);
1011 if (attr->key_size > MAX_BPF_STACK)
1012 return ERR_PTR(-E2BIG);
1013
1014 htab = kzalloc(sizeof(*htab), GFP_USER);
1015 if (!htab)
1016 return ERR_PTR(-ENOMEM);
1017
1018 bpf_map_init_from_attr(&htab->map, attr);
1019
1020 htab->buckets_num = roundup_pow_of_two(htab->map.max_entries);
1021 htab->elem_size = sizeof(struct bpf_shtab_elem) +
1022 round_up(htab->map.key_size, 8);
1023 if (htab->buckets_num == 0 ||
1024 htab->buckets_num > U32_MAX / sizeof(struct bpf_shtab_bucket)) {
1025 err = -EINVAL;
1026 goto free_htab;
1027 }
1028
1029 cost = (u64) htab->buckets_num * sizeof(struct bpf_shtab_bucket) +
1030 (u64) htab->elem_size * htab->map.max_entries;
1031 if (cost >= U32_MAX - PAGE_SIZE) {
1032 err = -EINVAL;
1033 goto free_htab;
1034 }
1035 err = bpf_map_charge_init(&htab->map.memory, cost);
1036 if (err)
1037 goto free_htab;
1038
1039 htab->buckets = bpf_map_area_alloc(htab->buckets_num *
1040 sizeof(struct bpf_shtab_bucket),
1041 htab->map.numa_node);
1042 if (!htab->buckets) {
1043 bpf_map_charge_finish(&htab->map.memory);
1044 err = -ENOMEM;
1045 goto free_htab;
1046 }
1047
1048 for (i = 0; i < htab->buckets_num; i++) {
1049 INIT_HLIST_HEAD(&htab->buckets[i].head);
1050 raw_spin_lock_init(&htab->buckets[i].lock);
1051 }
1052
1053 return &htab->map;
1054free_htab:
1055 kfree(htab);
1056 return ERR_PTR(err);
1057}
1058
1059static void sock_hash_free(struct bpf_map *map)
1060{
1061 struct bpf_shtab *htab = container_of(map, struct bpf_shtab, map);
1062 struct bpf_shtab_bucket *bucket;
1063 struct hlist_head unlink_list;
1064 struct bpf_shtab_elem *elem;
1065 struct hlist_node *node;
1066 int i;
1067
1068 /* After the sync no updates or deletes will be in-flight so it
1069 * is safe to walk map and remove entries without risking a race
1070 * in EEXIST update case.
1071 */
1072 synchronize_rcu();
1073 for (i = 0; i < htab->buckets_num; i++) {
1074 bucket = sock_hash_select_bucket(htab, i);
1075
1076 /* We are racing with sock_hash_delete_from_link to
1077 * enter the spin-lock critical section. Every socket on
1078 * the list is still linked to sockhash. Since link
1079 * exists, psock exists and holds a ref to socket. That
1080 * lets us to grab a socket ref too.
1081 */
1082 raw_spin_lock_bh(&bucket->lock);
1083 hlist_for_each_entry(elem, &bucket->head, node)
1084 sock_hold(elem->sk);
1085 hlist_move_list(&bucket->head, &unlink_list);
1086 raw_spin_unlock_bh(&bucket->lock);
1087
1088 /* Process removed entries out of atomic context to
1089 * block for socket lock before deleting the psock's
1090 * link to sockhash.
1091 */
1092 hlist_for_each_entry_safe(elem, node, &unlink_list, node) {
1093 hlist_del(&elem->node);
1094 lock_sock(elem->sk);
1095 rcu_read_lock();
1096 sock_map_unref(elem->sk, elem);
1097 rcu_read_unlock();
1098 release_sock(elem->sk);
1099 sock_put(elem->sk);
1100 sock_hash_free_elem(htab, elem);
1101 }
1102 }
1103
1104 /* wait for psock readers accessing its map link */
1105 synchronize_rcu();
1106
1107 bpf_map_area_free(htab->buckets);
1108 kfree(htab);
1109}
1110
1111static void *sock_hash_lookup_sys(struct bpf_map *map, void *key)
1112{
1113 struct sock *sk;
1114
1115 if (map->value_size != sizeof(u64))
1116 return ERR_PTR(-ENOSPC);
1117
1118 sk = __sock_hash_lookup_elem(map, key);
1119 if (!sk)
1120 return ERR_PTR(-ENOENT);
1121
1122 sock_gen_cookie(sk);
1123 return &sk->sk_cookie;
1124}
1125
1126static void *sock_hash_lookup(struct bpf_map *map, void *key)
1127{
1128 struct sock *sk;
1129
1130 sk = __sock_hash_lookup_elem(map, key);
1131 if (!sk || !sk_fullsock(sk))
1132 return NULL;
1133 if (sk_is_refcounted(sk) && !refcount_inc_not_zero(&sk->sk_refcnt))
1134 return NULL;
1135 return sk;
1136}
1137
1138static void sock_hash_release_progs(struct bpf_map *map)
1139{
1140 psock_progs_drop(&container_of(map, struct bpf_shtab, map)->progs);
1141}
1142
1143BPF_CALL_4(bpf_sock_hash_update, struct bpf_sock_ops_kern *, sops,
1144 struct bpf_map *, map, void *, key, u64, flags)
1145{
1146 WARN_ON_ONCE(!rcu_read_lock_held());
1147
1148 if (likely(sock_map_sk_is_suitable(sops->sk) &&
1149 sock_map_op_okay(sops)))
1150 return sock_hash_update_common(map, key, sops->sk, flags);
1151 return -EOPNOTSUPP;
1152}
1153
1154const struct bpf_func_proto bpf_sock_hash_update_proto = {
1155 .func = bpf_sock_hash_update,
1156 .gpl_only = false,
1157 .pkt_access = true,
1158 .ret_type = RET_INTEGER,
1159 .arg1_type = ARG_PTR_TO_CTX,
1160 .arg2_type = ARG_CONST_MAP_PTR,
1161 .arg3_type = ARG_PTR_TO_MAP_KEY,
1162 .arg4_type = ARG_ANYTHING,
1163};
1164
1165BPF_CALL_4(bpf_sk_redirect_hash, struct sk_buff *, skb,
1166 struct bpf_map *, map, void *, key, u64, flags)
1167{
1168 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
1169 struct sock *sk;
1170
1171 if (unlikely(flags & ~(BPF_F_INGRESS)))
1172 return SK_DROP;
1173
1174 sk = __sock_hash_lookup_elem(map, key);
1175 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
1176 return SK_DROP;
1177
1178 tcb->bpf.flags = flags;
1179 tcb->bpf.sk_redir = sk;
1180 return SK_PASS;
1181}
1182
1183const struct bpf_func_proto bpf_sk_redirect_hash_proto = {
1184 .func = bpf_sk_redirect_hash,
1185 .gpl_only = false,
1186 .ret_type = RET_INTEGER,
1187 .arg1_type = ARG_PTR_TO_CTX,
1188 .arg2_type = ARG_CONST_MAP_PTR,
1189 .arg3_type = ARG_PTR_TO_MAP_KEY,
1190 .arg4_type = ARG_ANYTHING,
1191};
1192
1193BPF_CALL_4(bpf_msg_redirect_hash, struct sk_msg *, msg,
1194 struct bpf_map *, map, void *, key, u64, flags)
1195{
1196 struct sock *sk;
1197
1198 if (unlikely(flags & ~(BPF_F_INGRESS)))
1199 return SK_DROP;
1200
1201 sk = __sock_hash_lookup_elem(map, key);
1202 if (unlikely(!sk || !sock_map_redirect_allowed(sk)))
1203 return SK_DROP;
1204
1205 msg->flags = flags;
1206 msg->sk_redir = sk;
1207 return SK_PASS;
1208}
1209
1210const struct bpf_func_proto bpf_msg_redirect_hash_proto = {
1211 .func = bpf_msg_redirect_hash,
1212 .gpl_only = false,
1213 .ret_type = RET_INTEGER,
1214 .arg1_type = ARG_PTR_TO_CTX,
1215 .arg2_type = ARG_CONST_MAP_PTR,
1216 .arg3_type = ARG_PTR_TO_MAP_KEY,
1217 .arg4_type = ARG_ANYTHING,
1218};
1219
1220static int sock_hash_map_btf_id;
1221const struct bpf_map_ops sock_hash_ops = {
1222 .map_alloc = sock_hash_alloc,
1223 .map_free = sock_hash_free,
1224 .map_get_next_key = sock_hash_get_next_key,
1225 .map_update_elem = sock_hash_update_elem,
1226 .map_delete_elem = sock_hash_delete_elem,
1227 .map_lookup_elem = sock_hash_lookup,
1228 .map_lookup_elem_sys_only = sock_hash_lookup_sys,
1229 .map_release_uref = sock_hash_release_progs,
1230 .map_check_btf = map_check_no_btf,
1231 .map_btf_name = "bpf_shtab",
1232 .map_btf_id = &sock_hash_map_btf_id,
1233};
1234
1235static struct sk_psock_progs *sock_map_progs(struct bpf_map *map)
1236{
1237 switch (map->map_type) {
1238 case BPF_MAP_TYPE_SOCKMAP:
1239 return &container_of(map, struct bpf_stab, map)->progs;
1240 case BPF_MAP_TYPE_SOCKHASH:
1241 return &container_of(map, struct bpf_shtab, map)->progs;
1242 default:
1243 break;
1244 }
1245
1246 return NULL;
1247}
1248
1249int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
1250 struct bpf_prog *old, u32 which)
1251{
1252 struct sk_psock_progs *progs = sock_map_progs(map);
1253 struct bpf_prog **pprog;
1254
1255 if (!progs)
1256 return -EOPNOTSUPP;
1257
1258 switch (which) {
1259 case BPF_SK_MSG_VERDICT:
1260 pprog = &progs->msg_parser;
1261 break;
1262 case BPF_SK_SKB_STREAM_PARSER:
1263 pprog = &progs->skb_parser;
1264 break;
1265 case BPF_SK_SKB_STREAM_VERDICT:
1266 pprog = &progs->skb_verdict;
1267 break;
1268 default:
1269 return -EOPNOTSUPP;
1270 }
1271
1272 if (old)
1273 return psock_replace_prog(pprog, prog, old);
1274
1275 psock_set_prog(pprog, prog);
1276 return 0;
1277}
1278
1279static void sock_map_unlink(struct sock *sk, struct sk_psock_link *link)
1280{
1281 switch (link->map->map_type) {
1282 case BPF_MAP_TYPE_SOCKMAP:
1283 return sock_map_delete_from_link(link->map, sk,
1284 link->link_raw);
1285 case BPF_MAP_TYPE_SOCKHASH:
1286 return sock_hash_delete_from_link(link->map, sk,
1287 link->link_raw);
1288 default:
1289 break;
1290 }
1291}
1292
1293static void sock_map_remove_links(struct sock *sk, struct sk_psock *psock)
1294{
1295 struct sk_psock_link *link;
1296
1297 while ((link = sk_psock_link_pop(psock))) {
1298 sock_map_unlink(sk, link);
1299 sk_psock_free_link(link);
1300 }
1301}
1302
1303void sock_map_unhash(struct sock *sk)
1304{
1305 void (*saved_unhash)(struct sock *sk);
1306 struct sk_psock *psock;
1307
1308 rcu_read_lock();
1309 psock = sk_psock(sk);
1310 if (unlikely(!psock)) {
1311 rcu_read_unlock();
1312 if (sk->sk_prot->unhash)
1313 sk->sk_prot->unhash(sk);
1314 return;
1315 }
1316
1317 saved_unhash = psock->saved_unhash;
1318 sock_map_remove_links(sk, psock);
1319 rcu_read_unlock();
1320 saved_unhash(sk);
1321}
1322
1323void sock_map_close(struct sock *sk, long timeout)
1324{
1325 void (*saved_close)(struct sock *sk, long timeout);
1326 struct sk_psock *psock;
1327
1328 lock_sock(sk);
1329 rcu_read_lock();
1330 psock = sk_psock(sk);
1331 if (unlikely(!psock)) {
1332 rcu_read_unlock();
1333 release_sock(sk);
1334 return sk->sk_prot->close(sk, timeout);
1335 }
1336
1337 saved_close = psock->saved_close;
1338 sock_map_remove_links(sk, psock);
1339 rcu_read_unlock();
1340 release_sock(sk);
1341 saved_close(sk, timeout);
1342}