1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
3
4 #include <linux/skmsg.h>
5 #include <linux/filter.h>
6 #include <linux/bpf.h>
7 #include <linux/init.h>
8 #include <linux/wait.h>
9 #include <linux/util_macros.h>
10
11 #include <net/inet_common.h>
12 #include <net/tls.h>
13
tcp_eat_skb(struct sock * sk,struct sk_buff * skb)14 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb)
15 {
16 struct tcp_sock *tcp;
17 int copied;
18
19 if (!skb || !skb->len || !sk_is_tcp(sk))
20 return;
21
22 if (skb_bpf_strparser(skb))
23 return;
24
25 tcp = tcp_sk(sk);
26 copied = tcp->copied_seq + skb->len;
27 WRITE_ONCE(tcp->copied_seq, copied);
28 tcp_rcv_space_adjust(sk);
29 __tcp_cleanup_rbuf(sk, skb->len);
30 }
31
bpf_tcp_ingress(struct sock * sk,struct sk_psock * psock,struct sk_msg * msg,u32 apply_bytes)32 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
33 struct sk_msg *msg, u32 apply_bytes)
34 {
35 bool apply = apply_bytes;
36 struct scatterlist *sge;
37 u32 size, copied = 0;
38 struct sk_msg *tmp;
39 int i, ret = 0;
40
41 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL);
42 if (unlikely(!tmp))
43 return -ENOMEM;
44
45 lock_sock(sk);
46 tmp->sg.start = msg->sg.start;
47 i = msg->sg.start;
48 do {
49 sge = sk_msg_elem(msg, i);
50 size = (apply && apply_bytes < sge->length) ?
51 apply_bytes : sge->length;
52 if (!sk_wmem_schedule(sk, size)) {
53 if (!copied)
54 ret = -ENOMEM;
55 break;
56 }
57
58 sk_mem_charge(sk, size);
59 sk_msg_xfer(tmp, msg, i, size);
60 copied += size;
61 if (sge->length)
62 get_page(sk_msg_page(tmp, i));
63 sk_msg_iter_var_next(i);
64 tmp->sg.end = i;
65 if (apply) {
66 apply_bytes -= size;
67 if (!apply_bytes) {
68 if (sge->length)
69 sk_msg_iter_var_prev(i);
70 break;
71 }
72 }
73 } while (i != msg->sg.end);
74
75 if (!ret) {
76 msg->sg.start = i;
77 sk_psock_queue_msg(psock, tmp);
78 sk_psock_data_ready(sk, psock);
79 } else {
80 sk_msg_free(sk, tmp);
81 kfree(tmp);
82 }
83
84 release_sock(sk);
85 return ret;
86 }
87
tcp_bpf_push(struct sock * sk,struct sk_msg * msg,u32 apply_bytes,int flags,bool uncharge)88 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
89 int flags, bool uncharge)
90 {
91 struct msghdr msghdr = {};
92 bool apply = apply_bytes;
93 struct scatterlist *sge;
94 struct page *page;
95 int size, ret = 0;
96 u32 off;
97
98 while (1) {
99 struct bio_vec bvec;
100 bool has_tx_ulp;
101
102 sge = sk_msg_elem(msg, msg->sg.start);
103 size = (apply && apply_bytes < sge->length) ?
104 apply_bytes : sge->length;
105 off = sge->offset;
106 page = sg_page(sge);
107
108 tcp_rate_check_app_limited(sk);
109 retry:
110 msghdr.msg_flags = flags | MSG_SPLICE_PAGES;
111 has_tx_ulp = tls_sw_has_ctx_tx(sk);
112 if (has_tx_ulp)
113 msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY;
114
115 if (size < sge->length && msg->sg.start != msg->sg.end)
116 msghdr.msg_flags |= MSG_MORE;
117
118 bvec_set_page(&bvec, page, size, off);
119 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size);
120 ret = tcp_sendmsg_locked(sk, &msghdr, size);
121 if (ret <= 0)
122 return ret;
123
124 if (apply)
125 apply_bytes -= ret;
126 msg->sg.size -= ret;
127 sge->offset += ret;
128 sge->length -= ret;
129 if (uncharge)
130 sk_mem_uncharge(sk, ret);
131 if (ret != size) {
132 size -= ret;
133 off += ret;
134 goto retry;
135 }
136 if (!sge->length) {
137 put_page(page);
138 sk_msg_iter_next(msg, start);
139 sg_init_table(sge, 1);
140 if (msg->sg.start == msg->sg.end)
141 break;
142 }
143 if (apply && !apply_bytes)
144 break;
145 }
146
147 return 0;
148 }
149
tcp_bpf_push_locked(struct sock * sk,struct sk_msg * msg,u32 apply_bytes,int flags,bool uncharge)150 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
151 u32 apply_bytes, int flags, bool uncharge)
152 {
153 int ret;
154
155 lock_sock(sk);
156 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
157 release_sock(sk);
158 return ret;
159 }
160
tcp_bpf_sendmsg_redir(struct sock * sk,bool ingress,struct sk_msg * msg,u32 bytes,int flags)161 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress,
162 struct sk_msg *msg, u32 bytes, int flags)
163 {
164 struct sk_psock *psock = sk_psock_get(sk);
165 int ret;
166
167 if (unlikely(!psock))
168 return -EPIPE;
169
170 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes) :
171 tcp_bpf_push_locked(sk, msg, bytes, flags, false);
172 sk_psock_put(sk, psock);
173 return ret;
174 }
175 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
176
177 #ifdef CONFIG_BPF_SYSCALL
tcp_msg_wait_data(struct sock * sk,struct sk_psock * psock,long timeo)178 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
179 long timeo)
180 {
181 DEFINE_WAIT_FUNC(wait, woken_wake_function);
182 int ret = 0;
183
184 if (sk->sk_shutdown & RCV_SHUTDOWN)
185 return 1;
186
187 if (!timeo)
188 return ret;
189
190 add_wait_queue(sk_sleep(sk), &wait);
191 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
192 ret = sk_wait_event(sk, &timeo,
193 !list_empty(&psock->ingress_msg) ||
194 !skb_queue_empty_lockless(&sk->sk_receive_queue), &wait);
195 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
196 remove_wait_queue(sk_sleep(sk), &wait);
197 return ret;
198 }
199
is_next_msg_fin(struct sk_psock * psock)200 static bool is_next_msg_fin(struct sk_psock *psock)
201 {
202 struct scatterlist *sge;
203 struct sk_msg *msg_rx;
204 int i;
205
206 msg_rx = sk_psock_peek_msg(psock);
207 i = msg_rx->sg.start;
208 sge = sk_msg_elem(msg_rx, i);
209 if (!sge->length) {
210 struct sk_buff *skb = msg_rx->skb;
211
212 if (skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
213 return true;
214 }
215 return false;
216 }
217
tcp_bpf_recvmsg_parser(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)218 static int tcp_bpf_recvmsg_parser(struct sock *sk,
219 struct msghdr *msg,
220 size_t len,
221 int flags,
222 int *addr_len)
223 {
224 int peek = flags & MSG_PEEK;
225 struct sk_psock *psock;
226 struct tcp_sock *tcp;
227 int copied = 0;
228 u32 seq;
229
230 if (unlikely(flags & MSG_ERRQUEUE))
231 return inet_recv_error(sk, msg, len, addr_len);
232
233 if (!len)
234 return 0;
235
236 psock = sk_psock_get(sk);
237 if (unlikely(!psock))
238 return tcp_recvmsg(sk, msg, len, flags, addr_len);
239
240 lock_sock(sk);
241 tcp = tcp_sk(sk);
242 seq = tcp->copied_seq;
243 /* We may have received data on the sk_receive_queue pre-accept and
244 * then we can not use read_skb in this context because we haven't
245 * assigned a sk_socket yet so have no link to the ops. The work-around
246 * is to check the sk_receive_queue and in these cases read skbs off
247 * queue again. The read_skb hook is not running at this point because
248 * of lock_sock so we avoid having multiple runners in read_skb.
249 */
250 if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
251 tcp_data_ready(sk);
252 /* This handles the ENOMEM errors if we both receive data
253 * pre accept and are already under memory pressure. At least
254 * let user know to retry.
255 */
256 if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
257 copied = -EAGAIN;
258 goto out;
259 }
260 }
261
262 msg_bytes_ready:
263 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
264 /* The typical case for EFAULT is the socket was gracefully
265 * shutdown with a FIN pkt. So check here the other case is
266 * some error on copy_page_to_iter which would be unexpected.
267 * On fin return correct return code to zero.
268 */
269 if (copied == -EFAULT) {
270 bool is_fin = is_next_msg_fin(psock);
271
272 if (is_fin) {
273 copied = 0;
274 seq++;
275 goto out;
276 }
277 }
278 seq += copied;
279 if (!copied) {
280 long timeo;
281 int data;
282
283 if (sock_flag(sk, SOCK_DONE))
284 goto out;
285
286 if (sk->sk_err) {
287 copied = sock_error(sk);
288 goto out;
289 }
290
291 if (sk->sk_shutdown & RCV_SHUTDOWN)
292 goto out;
293
294 if (sk->sk_state == TCP_CLOSE) {
295 copied = -ENOTCONN;
296 goto out;
297 }
298
299 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
300 if (!timeo) {
301 copied = -EAGAIN;
302 goto out;
303 }
304
305 if (signal_pending(current)) {
306 copied = sock_intr_errno(timeo);
307 goto out;
308 }
309
310 data = tcp_msg_wait_data(sk, psock, timeo);
311 if (data < 0) {
312 copied = data;
313 goto unlock;
314 }
315 if (data && !sk_psock_queue_empty(psock))
316 goto msg_bytes_ready;
317 copied = -EAGAIN;
318 }
319 out:
320 if (!peek)
321 WRITE_ONCE(tcp->copied_seq, seq);
322 tcp_rcv_space_adjust(sk);
323 if (copied > 0)
324 __tcp_cleanup_rbuf(sk, copied);
325
326 unlock:
327 release_sock(sk);
328 sk_psock_put(sk, psock);
329 return copied;
330 }
331
tcp_bpf_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)332 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
333 int flags, int *addr_len)
334 {
335 struct sk_psock *psock;
336 int copied, ret;
337
338 if (unlikely(flags & MSG_ERRQUEUE))
339 return inet_recv_error(sk, msg, len, addr_len);
340
341 if (!len)
342 return 0;
343
344 psock = sk_psock_get(sk);
345 if (unlikely(!psock))
346 return tcp_recvmsg(sk, msg, len, flags, addr_len);
347 if (!skb_queue_empty(&sk->sk_receive_queue) &&
348 sk_psock_queue_empty(psock)) {
349 sk_psock_put(sk, psock);
350 return tcp_recvmsg(sk, msg, len, flags, addr_len);
351 }
352 lock_sock(sk);
353 msg_bytes_ready:
354 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
355 if (!copied) {
356 long timeo;
357 int data;
358
359 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
360 data = tcp_msg_wait_data(sk, psock, timeo);
361 if (data < 0) {
362 ret = data;
363 goto unlock;
364 }
365 if (data) {
366 if (!sk_psock_queue_empty(psock))
367 goto msg_bytes_ready;
368 release_sock(sk);
369 sk_psock_put(sk, psock);
370 return tcp_recvmsg(sk, msg, len, flags, addr_len);
371 }
372 copied = -EAGAIN;
373 }
374 ret = copied;
375
376 unlock:
377 release_sock(sk);
378 sk_psock_put(sk, psock);
379 return ret;
380 }
381
tcp_bpf_send_verdict(struct sock * sk,struct sk_psock * psock,struct sk_msg * msg,int * copied,int flags)382 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
383 struct sk_msg *msg, int *copied, int flags)
384 {
385 bool cork = false, enospc = sk_msg_full(msg), redir_ingress;
386 struct sock *sk_redir;
387 u32 tosend, origsize, sent, delta = 0;
388 u32 eval;
389 int ret;
390
391 more_data:
392 if (psock->eval == __SK_NONE) {
393 /* Track delta in msg size to add/subtract it on SK_DROP from
394 * returned to user copied size. This ensures user doesn't
395 * get a positive return code with msg_cut_data and SK_DROP
396 * verdict.
397 */
398 delta = msg->sg.size;
399 psock->eval = sk_psock_msg_verdict(sk, psock, msg);
400 delta -= msg->sg.size;
401 }
402
403 if (msg->cork_bytes &&
404 msg->cork_bytes > msg->sg.size && !enospc) {
405 psock->cork_bytes = msg->cork_bytes - msg->sg.size;
406 if (!psock->cork) {
407 psock->cork = kzalloc(sizeof(*psock->cork),
408 GFP_ATOMIC | __GFP_NOWARN);
409 if (!psock->cork)
410 return -ENOMEM;
411 }
412 memcpy(psock->cork, msg, sizeof(*msg));
413 return 0;
414 }
415
416 tosend = msg->sg.size;
417 if (psock->apply_bytes && psock->apply_bytes < tosend)
418 tosend = psock->apply_bytes;
419 eval = __SK_NONE;
420
421 switch (psock->eval) {
422 case __SK_PASS:
423 ret = tcp_bpf_push(sk, msg, tosend, flags, true);
424 if (unlikely(ret)) {
425 *copied -= sk_msg_free(sk, msg);
426 break;
427 }
428 sk_msg_apply_bytes(psock, tosend);
429 break;
430 case __SK_REDIRECT:
431 redir_ingress = psock->redir_ingress;
432 sk_redir = psock->sk_redir;
433 sk_msg_apply_bytes(psock, tosend);
434 if (!psock->apply_bytes) {
435 /* Clean up before releasing the sock lock. */
436 eval = psock->eval;
437 psock->eval = __SK_NONE;
438 psock->sk_redir = NULL;
439 }
440 if (psock->cork) {
441 cork = true;
442 psock->cork = NULL;
443 }
444 sk_msg_return(sk, msg, tosend);
445 release_sock(sk);
446
447 origsize = msg->sg.size;
448 ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress,
449 msg, tosend, flags);
450 sent = origsize - msg->sg.size;
451
452 if (eval == __SK_REDIRECT)
453 sock_put(sk_redir);
454
455 lock_sock(sk);
456 if (unlikely(ret < 0)) {
457 int free = sk_msg_free_nocharge(sk, msg);
458
459 if (!cork)
460 *copied -= free;
461 }
462 if (cork) {
463 sk_msg_free(sk, msg);
464 kfree(msg);
465 msg = NULL;
466 ret = 0;
467 }
468 break;
469 case __SK_DROP:
470 default:
471 sk_msg_free_partial(sk, msg, tosend);
472 sk_msg_apply_bytes(psock, tosend);
473 *copied -= (tosend + delta);
474 return -EACCES;
475 }
476
477 if (likely(!ret)) {
478 if (!psock->apply_bytes) {
479 psock->eval = __SK_NONE;
480 if (psock->sk_redir) {
481 sock_put(psock->sk_redir);
482 psock->sk_redir = NULL;
483 }
484 }
485 if (msg &&
486 msg->sg.data[msg->sg.start].page_link &&
487 msg->sg.data[msg->sg.start].length) {
488 if (eval == __SK_REDIRECT)
489 sk_mem_charge(sk, tosend - sent);
490 goto more_data;
491 }
492 }
493 return ret;
494 }
495
tcp_bpf_sendmsg(struct sock * sk,struct msghdr * msg,size_t size)496 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
497 {
498 struct sk_msg tmp, *msg_tx = NULL;
499 int copied = 0, err = 0;
500 struct sk_psock *psock;
501 long timeo;
502 int flags;
503
504 /* Don't let internal flags through */
505 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED);
506 flags |= MSG_NO_SHARED_FRAGS;
507
508 psock = sk_psock_get(sk);
509 if (unlikely(!psock))
510 return tcp_sendmsg(sk, msg, size);
511
512 lock_sock(sk);
513 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
514 while (msg_data_left(msg)) {
515 bool enospc = false;
516 u32 copy, osize;
517
518 if (sk->sk_err) {
519 err = -sk->sk_err;
520 goto out_err;
521 }
522
523 copy = msg_data_left(msg);
524 if (!sk_stream_memory_free(sk))
525 goto wait_for_sndbuf;
526 if (psock->cork) {
527 msg_tx = psock->cork;
528 } else {
529 msg_tx = &tmp;
530 sk_msg_init(msg_tx);
531 }
532
533 osize = msg_tx->sg.size;
534 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
535 if (err) {
536 if (err != -ENOSPC)
537 goto wait_for_memory;
538 enospc = true;
539 copy = msg_tx->sg.size - osize;
540 }
541
542 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
543 copy);
544 if (err < 0) {
545 sk_msg_trim(sk, msg_tx, osize);
546 goto out_err;
547 }
548
549 copied += copy;
550 if (psock->cork_bytes) {
551 if (size > psock->cork_bytes)
552 psock->cork_bytes = 0;
553 else
554 psock->cork_bytes -= size;
555 if (psock->cork_bytes && !enospc)
556 goto out_err;
557 /* All cork bytes are accounted, rerun the prog. */
558 psock->eval = __SK_NONE;
559 psock->cork_bytes = 0;
560 }
561
562 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
563 if (unlikely(err < 0))
564 goto out_err;
565 continue;
566 wait_for_sndbuf:
567 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
568 wait_for_memory:
569 err = sk_stream_wait_memory(sk, &timeo);
570 if (err) {
571 if (msg_tx && msg_tx != psock->cork)
572 sk_msg_free(sk, msg_tx);
573 goto out_err;
574 }
575 }
576 out_err:
577 if (err < 0)
578 err = sk_stream_error(sk, msg->msg_flags, err);
579 release_sock(sk);
580 sk_psock_put(sk, psock);
581 return copied > 0 ? copied : err;
582 }
583
584 enum {
585 TCP_BPF_IPV4,
586 TCP_BPF_IPV6,
587 TCP_BPF_NUM_PROTS,
588 };
589
590 enum {
591 TCP_BPF_BASE,
592 TCP_BPF_TX,
593 TCP_BPF_RX,
594 TCP_BPF_TXRX,
595 TCP_BPF_NUM_CFGS,
596 };
597
598 static struct proto *tcpv6_prot_saved __read_mostly;
599 static DEFINE_SPINLOCK(tcpv6_prot_lock);
600 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
601
tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],struct proto * base)602 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
603 struct proto *base)
604 {
605 prot[TCP_BPF_BASE] = *base;
606 prot[TCP_BPF_BASE].destroy = sock_map_destroy;
607 prot[TCP_BPF_BASE].close = sock_map_close;
608 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg;
609 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable;
610
611 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE];
612 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg;
613
614 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE];
615 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser;
616
617 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX];
618 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser;
619 }
620
tcp_bpf_check_v6_needs_rebuild(struct proto * ops)621 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops)
622 {
623 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
624 spin_lock_bh(&tcpv6_prot_lock);
625 if (likely(ops != tcpv6_prot_saved)) {
626 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
627 smp_store_release(&tcpv6_prot_saved, ops);
628 }
629 spin_unlock_bh(&tcpv6_prot_lock);
630 }
631 }
632
tcp_bpf_v4_build_proto(void)633 static int __init tcp_bpf_v4_build_proto(void)
634 {
635 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
636 return 0;
637 }
638 late_initcall(tcp_bpf_v4_build_proto);
639
tcp_bpf_assert_proto_ops(struct proto * ops)640 static int tcp_bpf_assert_proto_ops(struct proto *ops)
641 {
642 /* In order to avoid retpoline, we make assumptions when we call
643 * into ops if e.g. a psock is not present. Make sure they are
644 * indeed valid assumptions.
645 */
646 return ops->recvmsg == tcp_recvmsg &&
647 ops->sendmsg == tcp_sendmsg ? 0 : -ENOTSUPP;
648 }
649
tcp_bpf_update_proto(struct sock * sk,struct sk_psock * psock,bool restore)650 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
651 {
652 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
653 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
654
655 if (psock->progs.stream_verdict || psock->progs.skb_verdict) {
656 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX;
657 }
658
659 if (restore) {
660 if (inet_csk_has_ulp(sk)) {
661 /* TLS does not have an unhash proto in SW cases,
662 * but we need to ensure we stop using the sock_map
663 * unhash routine because the associated psock is being
664 * removed. So use the original unhash handler.
665 */
666 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash);
667 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
668 } else {
669 sk->sk_write_space = psock->saved_write_space;
670 /* Pairs with lockless read in sk_clone_lock() */
671 sock_replace_proto(sk, psock->sk_proto);
672 }
673 return 0;
674 }
675
676 if (sk->sk_family == AF_INET6) {
677 if (tcp_bpf_assert_proto_ops(psock->sk_proto))
678 return -EINVAL;
679
680 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto);
681 }
682
683 /* Pairs with lockless read in sk_clone_lock() */
684 sock_replace_proto(sk, &tcp_bpf_prots[family][config]);
685 return 0;
686 }
687 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto);
688
689 /* If a child got cloned from a listening socket that had tcp_bpf
690 * protocol callbacks installed, we need to restore the callbacks to
691 * the default ones because the child does not inherit the psock state
692 * that tcp_bpf callbacks expect.
693 */
tcp_bpf_clone(const struct sock * sk,struct sock * newsk)694 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
695 {
696 struct proto *prot = newsk->sk_prot;
697
698 if (is_insidevar(prot, tcp_bpf_prots))
699 newsk->sk_prot = sk->sk_prot_creator;
700 }
701 #endif /* CONFIG_BPF_SYSCALL */
702