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 #include <asm/ioctls.h>
14
tcp_eat_skb(struct sock * sk,struct sk_buff * skb)15 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb)
16 {
17 struct tcp_sock *tcp;
18 int copied;
19
20 if (!skb || !skb->len || !sk_is_tcp(sk))
21 return;
22
23 if (skb_bpf_strparser(skb))
24 return;
25
26 tcp = tcp_sk(sk);
27 copied = tcp->copied_seq + skb->len;
28 WRITE_ONCE(tcp->copied_seq, copied);
29 tcp_rcv_space_adjust(sk);
30 __tcp_cleanup_rbuf(sk, skb->len);
31 }
32
bpf_tcp_ingress(struct sock * sk,struct sk_psock * psock,struct sk_msg * msg,u32 apply_bytes)33 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
34 struct sk_msg *msg, u32 apply_bytes)
35 {
36 bool apply = apply_bytes;
37 struct scatterlist *sge;
38 u32 size, copied = 0;
39 struct sk_msg *tmp;
40 int i, ret = 0;
41
42 tmp = kzalloc_obj(*tmp, __GFP_NOWARN | GFP_KERNEL);
43 if (unlikely(!tmp))
44 return -ENOMEM;
45
46 lock_sock(sk);
47 tmp->sg.start = msg->sg.start;
48 i = msg->sg.start;
49 do {
50 sge = sk_msg_elem(msg, i);
51 size = (apply && apply_bytes < sge->length) ?
52 apply_bytes : sge->length;
53 if (!__sk_rmem_schedule(sk, size, false)) {
54 if (!copied)
55 ret = -ENOMEM;
56 break;
57 }
58
59 sk_mem_charge(sk, size);
60 atomic_add(size, &sk->sk_rmem_alloc);
61 sk_msg_xfer(tmp, msg, i, size);
62 copied += size;
63 if (sge->length)
64 get_page(sk_msg_page(tmp, i));
65 sk_msg_iter_var_next(i);
66 tmp->sg.end = i;
67 if (apply) {
68 apply_bytes -= size;
69 if (!apply_bytes) {
70 if (sge->length)
71 sk_msg_iter_var_prev(i);
72 break;
73 }
74 }
75 } while (i != msg->sg.end);
76
77 if (!ret) {
78 msg->sg.start = i;
79 if (!sk_psock_queue_msg(psock, tmp))
80 atomic_sub(copied, &sk->sk_rmem_alloc);
81 sk_psock_data_ready(sk, psock);
82 } else {
83 sk_msg_free(sk, tmp);
84 kfree(tmp);
85 }
86
87 release_sock(sk);
88 return ret;
89 }
90
tcp_bpf_push(struct sock * sk,struct sk_msg * msg,u32 apply_bytes,int flags,bool uncharge)91 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
92 int flags, bool uncharge)
93 {
94 struct msghdr msghdr = {};
95 bool apply = apply_bytes;
96 struct scatterlist *sge;
97 struct page *page;
98 int size, ret = 0;
99 u32 off;
100
101 while (1) {
102 struct bio_vec bvec;
103 bool has_tx_ulp;
104
105 sge = sk_msg_elem(msg, msg->sg.start);
106 size = (apply && apply_bytes < sge->length) ?
107 apply_bytes : sge->length;
108 off = sge->offset;
109 page = sg_page(sge);
110
111 tcp_rate_check_app_limited(sk);
112 retry:
113 msghdr.msg_flags = flags | MSG_SPLICE_PAGES;
114 has_tx_ulp = tls_sw_has_ctx_tx(sk);
115 if (has_tx_ulp)
116 msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY;
117
118 if (size < sge->length && msg->sg.start != msg->sg.end)
119 msghdr.msg_flags |= MSG_MORE;
120
121 bvec_set_page(&bvec, page, size, off);
122 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size);
123 ret = tcp_sendmsg_locked(sk, &msghdr, size);
124 if (ret <= 0)
125 return ret;
126
127 if (apply)
128 apply_bytes -= ret;
129 msg->sg.size -= ret;
130 sge->offset += ret;
131 sge->length -= ret;
132 if (uncharge)
133 sk_mem_uncharge(sk, ret);
134 if (ret != size) {
135 size -= ret;
136 off += ret;
137 goto retry;
138 }
139 if (!sge->length) {
140 put_page(page);
141 sk_msg_iter_next(msg, start);
142 sg_init_table(sge, 1);
143 if (msg->sg.start == msg->sg.end)
144 break;
145 }
146 if (apply && !apply_bytes)
147 break;
148 }
149
150 return 0;
151 }
152
tcp_bpf_push_locked(struct sock * sk,struct sk_msg * msg,u32 apply_bytes,int flags,bool uncharge)153 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
154 u32 apply_bytes, int flags, bool uncharge)
155 {
156 int ret;
157
158 lock_sock(sk);
159 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
160 release_sock(sk);
161 return ret;
162 }
163
tcp_bpf_sendmsg_redir(struct sock * sk,bool ingress,struct sk_msg * msg,u32 bytes,int flags)164 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress,
165 struct sk_msg *msg, u32 bytes, int flags)
166 {
167 struct sk_psock *psock = sk_psock_get(sk);
168 int ret;
169
170 if (unlikely(!psock))
171 return -EPIPE;
172
173 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes) :
174 tcp_bpf_push_locked(sk, msg, bytes, flags, false);
175 sk_psock_put(sk, psock);
176 return ret;
177 }
178 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
179
180 #ifdef CONFIG_BPF_SYSCALL
tcp_msg_wait_data(struct sock * sk,struct sk_psock * psock,long timeo)181 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
182 long timeo)
183 {
184 DEFINE_WAIT_FUNC(wait, woken_wake_function);
185 int ret = 0;
186
187 if (sk->sk_shutdown & RCV_SHUTDOWN)
188 return 1;
189
190 if (!timeo)
191 return ret;
192
193 add_wait_queue(sk_sleep(sk), &wait);
194 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
195 ret = sk_wait_event(sk, &timeo,
196 !list_empty(&psock->ingress_msg) ||
197 !skb_queue_empty_lockless(&sk->sk_receive_queue), &wait);
198 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
199 remove_wait_queue(sk_sleep(sk), &wait);
200 return ret;
201 }
202
is_next_msg_fin(struct sk_psock * psock)203 static bool is_next_msg_fin(struct sk_psock *psock)
204 {
205 struct scatterlist *sge;
206 struct sk_msg *msg_rx;
207 int i;
208
209 msg_rx = sk_psock_peek_msg(psock);
210 i = msg_rx->sg.start;
211 sge = sk_msg_elem(msg_rx, i);
212 if (!sge->length) {
213 struct sk_buff *skb = msg_rx->skb;
214
215 if (skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
216 return true;
217 }
218 return false;
219 }
220
tcp_bpf_recvmsg_parser(struct sock * sk,struct msghdr * msg,size_t len,int flags)221 static int tcp_bpf_recvmsg_parser(struct sock *sk,
222 struct msghdr *msg,
223 size_t len,
224 int flags)
225 {
226 int peek = flags & MSG_PEEK;
227 struct sk_psock *psock;
228 struct tcp_sock *tcp;
229 int copied_from_self = 0;
230 int copied = 0;
231 u32 seq;
232
233 if (unlikely(flags & MSG_ERRQUEUE))
234 return inet_recv_error(sk, msg, len);
235
236 if (!len)
237 return 0;
238
239 psock = sk_psock_get(sk);
240 if (unlikely(!psock))
241 return tcp_recvmsg(sk, msg, len, flags);
242
243 lock_sock(sk);
244 tcp = tcp_sk(sk);
245 seq = tcp->copied_seq;
246 /* We may have received data on the sk_receive_queue pre-accept and
247 * then we can not use read_skb in this context because we haven't
248 * assigned a sk_socket yet so have no link to the ops. The work-around
249 * is to check the sk_receive_queue and in these cases read skbs off
250 * queue again. The read_skb hook is not running at this point because
251 * of lock_sock so we avoid having multiple runners in read_skb.
252 */
253 if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
254 tcp_data_ready(sk);
255 /* This handles the ENOMEM errors if we both receive data
256 * pre accept and are already under memory pressure. At least
257 * let user know to retry.
258 */
259 if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
260 copied = -EAGAIN;
261 goto out;
262 }
263 }
264
265 msg_bytes_ready:
266 copied = __sk_msg_recvmsg(sk, psock, msg, len, flags, &copied_from_self);
267 /* The typical case for EFAULT is the socket was gracefully
268 * shutdown with a FIN pkt. So check here the other case is
269 * some error on copy_page_to_iter which would be unexpected.
270 * On fin return correct return code to zero.
271 */
272 if (copied == -EFAULT) {
273 bool is_fin = is_next_msg_fin(psock);
274
275 if (is_fin) {
276 copied = 0;
277 seq++;
278 goto out;
279 }
280 }
281 seq += copied_from_self;
282 if (!copied) {
283 long timeo;
284 int data;
285
286 if (sock_flag(sk, SOCK_DONE))
287 goto out;
288
289 if (sk->sk_err) {
290 copied = sock_error(sk);
291 goto out;
292 }
293
294 if (sk->sk_shutdown & RCV_SHUTDOWN)
295 goto out;
296
297 if (sk->sk_state == TCP_CLOSE) {
298 copied = -ENOTCONN;
299 goto out;
300 }
301
302 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
303 if (!timeo) {
304 copied = -EAGAIN;
305 goto out;
306 }
307
308 if (signal_pending(current)) {
309 copied = sock_intr_errno(timeo);
310 goto out;
311 }
312
313 data = tcp_msg_wait_data(sk, psock, timeo);
314 if (data < 0) {
315 copied = data;
316 goto unlock;
317 }
318 if (data && !sk_psock_queue_empty(psock))
319 goto msg_bytes_ready;
320 copied = -EAGAIN;
321 }
322 out:
323 if (!peek)
324 WRITE_ONCE(tcp->copied_seq, seq);
325 tcp_rcv_space_adjust(sk);
326 if (copied > 0)
327 __tcp_cleanup_rbuf(sk, copied);
328
329 unlock:
330 release_sock(sk);
331 sk_psock_put(sk, psock);
332 return copied;
333 }
334
tcp_bpf_ioctl(struct sock * sk,int cmd,int * karg)335 static int tcp_bpf_ioctl(struct sock *sk, int cmd, int *karg)
336 {
337 struct sk_psock *psock;
338 bool slow;
339
340 if (cmd != SIOCINQ)
341 return tcp_ioctl(sk, cmd, karg);
342
343 /* works similar as tcp_ioctl */
344 if (sk->sk_state == TCP_LISTEN)
345 return -EINVAL;
346
347 slow = lock_sock_fast(sk);
348 psock = sk_psock_get(sk);
349 if (unlikely(!psock)) {
350 unlock_sock_fast(sk, slow);
351 return tcp_ioctl(sk, cmd, karg);
352 }
353 *karg = sk_psock_get_msg_len_nolock(psock);
354 /* Without a verdict program, ingress data is never diverted to
355 * ingress_msg: it stays in sk_receive_queue and is read through
356 * the fallback to tcp_recvmsg(), so account for it like
357 * tcp_ioctl() does.
358 */
359 if (!READ_ONCE(psock->progs.stream_verdict) &&
360 !READ_ONCE(psock->progs.skb_verdict))
361 *karg += tcp_inq(sk);
362 sk_psock_put(sk, psock);
363 unlock_sock_fast(sk, slow);
364
365 return 0;
366 }
367
tcp_bpf_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags)368 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
369 int flags)
370 {
371 struct sk_psock *psock;
372 int copied, ret;
373
374 if (unlikely(flags & MSG_ERRQUEUE))
375 return inet_recv_error(sk, msg, len);
376
377 if (!len)
378 return 0;
379
380 psock = sk_psock_get(sk);
381 if (unlikely(!psock))
382 return tcp_recvmsg(sk, msg, len, flags);
383 if (!skb_queue_empty(&sk->sk_receive_queue) &&
384 sk_psock_queue_empty(psock)) {
385 sk_psock_put(sk, psock);
386 return tcp_recvmsg(sk, msg, len, flags);
387 }
388 lock_sock(sk);
389 msg_bytes_ready:
390 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
391 if (!copied) {
392 long timeo;
393 int data;
394
395 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
396 data = tcp_msg_wait_data(sk, psock, timeo);
397 if (data < 0) {
398 ret = data;
399 goto unlock;
400 }
401 if (data) {
402 if (!sk_psock_queue_empty(psock))
403 goto msg_bytes_ready;
404 release_sock(sk);
405 sk_psock_put(sk, psock);
406 return tcp_recvmsg(sk, msg, len, flags);
407 }
408 copied = -EAGAIN;
409 }
410 ret = copied;
411
412 unlock:
413 release_sock(sk);
414 sk_psock_put(sk, psock);
415 return ret;
416 }
417
tcp_bpf_send_verdict(struct sock * sk,struct sk_psock * psock,struct sk_msg * msg,int * copied,int flags)418 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
419 struct sk_msg *msg, int *copied, int flags)
420 {
421 bool cork = false, enospc = sk_msg_full(msg), redir_ingress;
422 struct sock *sk_redir;
423 u32 tosend, origsize, sent, delta = 0;
424 u32 eval;
425 int ret;
426
427 more_data:
428 if (psock->eval == __SK_NONE) {
429 /* Track delta in msg size to add/subtract it on SK_DROP from
430 * returned to user copied size. This ensures user doesn't
431 * get a positive return code with msg_cut_data and SK_DROP
432 * verdict.
433 */
434 delta = msg->sg.size;
435 psock->eval = sk_psock_msg_verdict(sk, psock, msg);
436 delta -= msg->sg.size;
437 }
438
439 if (msg->cork_bytes &&
440 msg->cork_bytes > msg->sg.size && !enospc) {
441 psock->cork_bytes = msg->cork_bytes - msg->sg.size;
442 if (!psock->cork) {
443 psock->cork = kzalloc_obj(*psock->cork,
444 GFP_ATOMIC | __GFP_NOWARN);
445 if (!psock->cork) {
446 sk_msg_free(sk, msg);
447 *copied = 0;
448 return -ENOMEM;
449 }
450 }
451 memcpy(psock->cork, msg, sizeof(*msg));
452 return 0;
453 }
454
455 tosend = msg->sg.size;
456 if (psock->apply_bytes && psock->apply_bytes < tosend)
457 tosend = psock->apply_bytes;
458 eval = __SK_NONE;
459
460 switch (psock->eval) {
461 case __SK_PASS:
462 ret = tcp_bpf_push(sk, msg, tosend, flags, true);
463 if (unlikely(ret)) {
464 *copied -= sk_msg_free(sk, msg);
465 break;
466 }
467 sk_msg_apply_bytes(psock, tosend);
468 break;
469 case __SK_REDIRECT:
470 redir_ingress = psock->redir_ingress;
471 sk_redir = psock->sk_redir;
472 sock_hold(sk_redir);
473 sk_msg_apply_bytes(psock, tosend);
474 if (!psock->apply_bytes) {
475 /* Clean up before releasing the sock lock. */
476 eval = psock->eval;
477 psock->eval = __SK_NONE;
478 psock->sk_redir = NULL;
479 }
480 if (psock->cork) {
481 cork = true;
482 psock->cork = NULL;
483 }
484 release_sock(sk);
485
486 origsize = msg->sg.size;
487 ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress,
488 msg, tosend, flags);
489 sent = origsize - msg->sg.size;
490
491 if (eval == __SK_REDIRECT)
492 sock_put(sk_redir);
493 sock_put(sk_redir);
494
495 lock_sock(sk);
496 sk_mem_uncharge(sk, sent);
497 if (unlikely(ret < 0)) {
498 int free = sk_msg_free(sk, msg);
499
500 if (!cork)
501 *copied -= free;
502 }
503 if (cork) {
504 sk_msg_free(sk, msg);
505 kfree(msg);
506 msg = NULL;
507 ret = 0;
508 }
509 break;
510 case __SK_DROP:
511 default:
512 sk_msg_free(sk, msg);
513 sk_msg_apply_bytes(psock, tosend);
514 *copied -= (tosend + delta);
515 return -EACCES;
516 }
517
518 if (likely(!ret)) {
519 if (!psock->apply_bytes) {
520 psock->eval = __SK_NONE;
521 if (psock->sk_redir) {
522 sock_put(psock->sk_redir);
523 psock->sk_redir = NULL;
524 }
525 }
526 if (msg &&
527 msg->sg.data[msg->sg.start].page_link &&
528 msg->sg.data[msg->sg.start].length)
529 goto more_data;
530 }
531 return ret;
532 }
533
tcp_bpf_sendmsg(struct sock * sk,struct msghdr * msg,size_t size)534 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
535 {
536 struct sk_msg tmp, *msg_tx = NULL;
537 int copied = 0, err = 0, ret = 0;
538 struct sk_psock *psock;
539 long timeo;
540 int flags;
541
542 /* Don't let internal flags through */
543 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED);
544 flags |= MSG_NO_SHARED_FRAGS;
545
546 psock = sk_psock_get(sk);
547 if (unlikely(!psock))
548 return tcp_sendmsg(sk, msg, size);
549
550 lock_sock(sk);
551 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
552 while (msg_data_left(msg)) {
553 bool enospc = false;
554 u32 copy, osize;
555
556 if (sk->sk_err) {
557 err = -sk->sk_err;
558 goto out_err;
559 }
560
561 copy = msg_data_left(msg);
562 if (!sk_stream_memory_free(sk))
563 goto wait_for_sndbuf;
564 if (psock->cork) {
565 msg_tx = psock->cork;
566 } else {
567 msg_tx = &tmp;
568 sk_msg_init(msg_tx);
569 }
570
571 osize = msg_tx->sg.size;
572 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
573 if (err) {
574 if (err != -ENOSPC)
575 goto wait_for_memory;
576 enospc = true;
577 copy = msg_tx->sg.size - osize;
578 }
579
580 ret = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
581 copy);
582 if (ret < 0) {
583 sk_msg_trim(sk, msg_tx, osize);
584 goto out_err;
585 }
586
587 copied += ret;
588 if (psock->cork_bytes) {
589 if (size > psock->cork_bytes)
590 psock->cork_bytes = 0;
591 else
592 psock->cork_bytes -= size;
593 if (psock->cork_bytes && !enospc)
594 goto out_err;
595 /* All cork bytes are accounted, rerun the prog. */
596 psock->eval = __SK_NONE;
597 psock->cork_bytes = 0;
598 }
599
600 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
601 if (unlikely(err < 0))
602 goto out_err;
603 continue;
604 wait_for_sndbuf:
605 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
606 wait_for_memory:
607 err = sk_stream_wait_memory(sk, &timeo);
608 if (err) {
609 if (msg_tx == &tmp)
610 sk_msg_free(sk, msg_tx);
611 goto out_err;
612 }
613 }
614 out_err:
615 if (err < 0)
616 err = sk_stream_error(sk, msg->msg_flags, err);
617 release_sock(sk);
618 sk_psock_put(sk, psock);
619 return copied > 0 ? copied : err;
620 }
621
622 enum {
623 TCP_BPF_IPV4,
624 TCP_BPF_IPV6,
625 TCP_BPF_NUM_PROTS,
626 };
627
628 enum {
629 TCP_BPF_BASE,
630 TCP_BPF_TX,
631 TCP_BPF_RX,
632 TCP_BPF_TXRX,
633 TCP_BPF_NUM_CFGS,
634 };
635
636 static struct proto *tcpv6_prot_saved __read_mostly;
637 static DEFINE_SPINLOCK(tcpv6_prot_lock);
638 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
639
tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],struct proto * base)640 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
641 struct proto *base)
642 {
643 prot[TCP_BPF_BASE] = *base;
644 prot[TCP_BPF_BASE].destroy = sock_map_destroy;
645 prot[TCP_BPF_BASE].close = sock_map_close;
646 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg;
647 prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable;
648 prot[TCP_BPF_BASE].ioctl = tcp_bpf_ioctl;
649
650 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE];
651 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg;
652
653 prot[TCP_BPF_RX] = prot[TCP_BPF_BASE];
654 prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser;
655
656 prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX];
657 prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser;
658 }
659
tcp_bpf_check_v6_needs_rebuild(struct proto * ops)660 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops)
661 {
662 if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
663 spin_lock_bh(&tcpv6_prot_lock);
664 if (likely(ops != tcpv6_prot_saved)) {
665 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
666 smp_store_release(&tcpv6_prot_saved, ops);
667 }
668 spin_unlock_bh(&tcpv6_prot_lock);
669 }
670 }
671
tcp_bpf_v4_build_proto(void)672 static int __init tcp_bpf_v4_build_proto(void)
673 {
674 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
675 return 0;
676 }
677 late_initcall(tcp_bpf_v4_build_proto);
678
tcp_bpf_assert_proto_ops(struct proto * ops)679 static int tcp_bpf_assert_proto_ops(struct proto *ops)
680 {
681 /* In order to avoid retpoline, we make assumptions when we call
682 * into ops if e.g. a psock is not present. Make sure they are
683 * indeed valid assumptions.
684 */
685 return ops->recvmsg == tcp_recvmsg &&
686 ops->sendmsg == tcp_sendmsg ? 0 : -ENOTSUPP;
687 }
688
689 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
tcp_bpf_strp_read_sock(struct strparser * strp,read_descriptor_t * desc,sk_read_actor_t recv_actor)690 int tcp_bpf_strp_read_sock(struct strparser *strp, read_descriptor_t *desc,
691 sk_read_actor_t recv_actor)
692 {
693 struct sock *sk = strp->sk;
694 struct sk_psock *psock;
695 struct tcp_sock *tp;
696 int copied = 0;
697
698 tp = tcp_sk(sk);
699 rcu_read_lock();
700 psock = sk_psock(sk);
701 if (WARN_ON_ONCE(!psock)) {
702 desc->error = -EINVAL;
703 goto out;
704 }
705
706 psock->ingress_bytes = 0;
707 copied = tcp_read_sock_noack(sk, desc, recv_actor, true,
708 &psock->copied_seq);
709 if (copied < 0)
710 goto out;
711 /* recv_actor may redirect skb to another socket (SK_REDIRECT) or
712 * just put skb into ingress queue of current socket (SK_PASS).
713 * For SK_REDIRECT, we need to ack the frame immediately but for
714 * SK_PASS, we want to delay the ack until tcp_bpf_recvmsg_parser().
715 */
716 tp->copied_seq = psock->copied_seq - psock->ingress_bytes;
717 tcp_rcv_space_adjust(sk);
718 __tcp_cleanup_rbuf(sk, copied - psock->ingress_bytes);
719 out:
720 rcu_read_unlock();
721 return copied;
722 }
723 #endif /* CONFIG_BPF_STREAM_PARSER */
724
tcp_bpf_update_proto(struct sock * sk,struct sk_psock * psock,bool restore)725 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
726 {
727 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
728 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
729
730 if (psock->progs.stream_verdict || psock->progs.skb_verdict) {
731 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX;
732 }
733
734 if (restore) {
735 if (inet_csk_has_ulp(sk)) {
736 /* TLS does not have an unhash proto in SW cases,
737 * but we need to ensure we stop using the sock_map
738 * unhash routine because the associated psock is being
739 * removed. So use the original unhash handler.
740 */
741 WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash);
742 tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
743 } else {
744 WRITE_ONCE(sk->sk_write_space, psock->saved_write_space);
745 /* Pairs with lockless read in sk_clone_lock() */
746 sock_replace_proto(sk, psock->sk_proto);
747 }
748 return 0;
749 }
750
751 if (sk->sk_family == AF_INET6) {
752 if (tcp_bpf_assert_proto_ops(psock->sk_proto))
753 return -EINVAL;
754
755 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto);
756 }
757
758 /* Pairs with lockless read in sk_clone_lock() */
759 sock_replace_proto(sk, &tcp_bpf_prots[family][config]);
760 return 0;
761 }
762 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto);
763
764 /* If a child got cloned from a listening socket that had tcp_bpf
765 * protocol callbacks installed, we need to restore the callbacks to
766 * the default ones because the child does not inherit the psock state
767 * that tcp_bpf callbacks expect.
768 */
tcp_bpf_clone(const struct sock * sk,struct sock * newsk)769 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
770 {
771 struct proto *prot = newsk->sk_prot;
772
773 if (is_insidevar(prot, tcp_bpf_prots))
774 newsk->sk_prot = sk->sk_prot_creator;
775 }
776 #endif /* CONFIG_BPF_SYSCALL */
777