xref: /openbmc/linux/net/core/sock_map.c (revision 8ec90bfd) 
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 
16 struct 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 
26 static 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);
61 free_stab:
62 	kfree(stab);
63 	return ERR_PTR(err);
64 }
65 
66 int 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 
85 int 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);
113 put_prog:
114 	bpf_prog_put(prog);
115 put_map:
116 	fdput(f);
117 	return ret;
118 }
119 
120 static 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 
128 static 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 
136 static 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 
147 static 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 
173 static 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 
183 static 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 
209 static 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 	}
224 out:
225 	rcu_read_unlock();
226 	return psock;
227 }
228 
229 static 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;
301 out_drop:
302 	sk_psock_put(sk, psock);
303 out_progs:
304 	if (msg_parser)
305 		bpf_prog_put(msg_parser);
306 out:
307 	if (skb_progs) {
308 		bpf_prog_put(skb_verdict);
309 		bpf_prog_put(skb_parser);
310 	}
311 	return ret;
312 }
313 
314 static 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 
335 static 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 
366 static void sock_map_release_progs(struct bpf_map *map)
367 {
368 	psock_progs_drop(&container_of(map, struct bpf_stab, map)->progs);
369 }
370 
371 static 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 
382 static 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 
394 static 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 
409 static 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 
429 static 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 
437 static 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 
450 static 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 
465 static bool sock_map_redirect_allowed(const struct sock *sk);
466 
467 static 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;
518 out_unlock:
519 	raw_spin_unlock_bh(&stab->lock);
520 	if (psock)
521 		sk_psock_put(sk, psock);
522 out_free:
523 	sk_psock_free_link(link);
524 	return ret;
525 }
526 
527 static 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 
534 static bool sk_is_tcp(const struct sock *sk)
535 {
536 	return sk->sk_type == SOCK_STREAM &&
537 	       sk->sk_protocol == IPPROTO_TCP;
538 }
539 
540 static bool sk_is_udp(const struct sock *sk)
541 {
542 	return sk->sk_type == SOCK_DGRAM &&
543 	       sk->sk_protocol == IPPROTO_UDP;
544 }
545 
546 static bool sock_map_redirect_allowed(const struct sock *sk)
547 {
548 	return sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN;
549 }
550 
551 static bool sock_map_sk_is_suitable(const struct sock *sk)
552 {
553 	return sk_is_tcp(sk) || sk_is_udp(sk);
554 }
555 
556 static 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 
566 static 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);
601 out:
602 	fput(sock->file);
603 	return ret;
604 }
605 
606 BPF_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 
618 const 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 
629 BPF_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 
647 const 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 
657 BPF_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 
674 const 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 
684 static int sock_map_btf_id;
685 const 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 
699 struct 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 
707 struct bpf_shtab_bucket {
708 	struct hlist_head head;
709 	raw_spinlock_t lock;
710 };
711 
712 struct 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 
721 static inline u32 sock_hash_bucket_hash(const void *key, u32 len)
722 {
723 	return jhash(key, len, 0);
724 }
725 
726 static 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 
732 static struct bpf_shtab_elem *
733 sock_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 
747 static 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 
763 static 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 
770 static 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 
795 static 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 
818 static 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 
844 static 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;
910 out_unlock:
911 	raw_spin_unlock_bh(&bucket->lock);
912 	sk_psock_put(sk, psock);
913 out_free:
914 	sk_psock_free_link(link);
915 	return ret;
916 }
917 
918 static 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);
952 out:
953 	fput(sock->file);
954 	return ret;
955 }
956 
957 static 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++;
983 find_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 
997 static 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;
1054 free_htab:
1055 	kfree(htab);
1056 	return ERR_PTR(err);
1057 }
1058 
1059 static 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 
1111 static 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 
1126 static 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 
1138 static void sock_hash_release_progs(struct bpf_map *map)
1139 {
1140 	psock_progs_drop(&container_of(map, struct bpf_shtab, map)->progs);
1141 }
1142 
1143 BPF_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 
1154 const 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 
1165 BPF_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 
1183 const 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 
1193 BPF_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 
1210 const 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 
1220 static int sock_hash_map_btf_id;
1221 const 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 
1235 static 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 
1249 int 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 
1279 static 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 
1293 static 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 
1303 void 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 
1323 void 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 }
1343