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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/skmsg.h>
5#include <linux/skbuff.h>
6#include <linux/scatterlist.h>
7
8#include <net/sock.h>
9#include <net/tcp.h>
10#include <net/tls.h>
11#include <trace/events/sock.h>
12
13static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
14{
15 if (msg->sg.end > msg->sg.start &&
16 elem_first_coalesce < msg->sg.end)
17 return true;
18
19 if (msg->sg.end < msg->sg.start &&
20 (elem_first_coalesce > msg->sg.start ||
21 elem_first_coalesce < msg->sg.end))
22 return true;
23
24 return false;
25}
26
27int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
28 int elem_first_coalesce)
29{
30 struct page_frag *pfrag = sk_page_frag(sk);
31 u32 osize = msg->sg.size;
32 int ret = 0;
33
34 len -= msg->sg.size;
35 while (len > 0) {
36 struct scatterlist *sge;
37 u32 orig_offset;
38 int use, i;
39
40 if (!sk_page_frag_refill(sk, pfrag)) {
41 ret = -ENOMEM;
42 goto msg_trim;
43 }
44
45 orig_offset = pfrag->offset;
46 use = min_t(int, len, pfrag->size - orig_offset);
47 if (!sk_wmem_schedule(sk, use)) {
48 ret = -ENOMEM;
49 goto msg_trim;
50 }
51
52 i = msg->sg.end;
53 sk_msg_iter_var_prev(i);
54 sge = &msg->sg.data[i];
55
56 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
57 sg_page(sge) == pfrag->page &&
58 sge->offset + sge->length == orig_offset) {
59 sge->length += use;
60 } else {
61 if (sk_msg_full(msg)) {
62 ret = -ENOSPC;
63 break;
64 }
65
66 sge = &msg->sg.data[msg->sg.end];
67 sg_unmark_end(sge);
68 sg_set_page(sge, pfrag->page, use, orig_offset);
69 get_page(pfrag->page);
70 sk_msg_iter_next(msg, end);
71 }
72
73 sk_mem_charge(sk, use);
74 msg->sg.size += use;
75 pfrag->offset += use;
76 len -= use;
77 }
78
79 return ret;
80
81msg_trim:
82 sk_msg_trim(sk, msg, osize);
83 return ret;
84}
85EXPORT_SYMBOL_GPL(sk_msg_alloc);
86
87int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
88 u32 off, u32 len)
89{
90 int i = src->sg.start;
91 struct scatterlist *sge = sk_msg_elem(src, i);
92 struct scatterlist *sgd = NULL;
93 u32 sge_len, sge_off;
94
95 while (off) {
96 if (sge->length > off)
97 break;
98 off -= sge->length;
99 sk_msg_iter_var_next(i);
100 if (i == src->sg.end && off)
101 return -ENOSPC;
102 sge = sk_msg_elem(src, i);
103 }
104
105 while (len) {
106 sge_len = sge->length - off;
107 if (sge_len > len)
108 sge_len = len;
109
110 if (dst->sg.end)
111 sgd = sk_msg_elem(dst, dst->sg.end - 1);
112
113 if (sgd &&
114 (sg_page(sge) == sg_page(sgd)) &&
115 (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
116 sgd->length += sge_len;
117 dst->sg.size += sge_len;
118 } else if (!sk_msg_full(dst)) {
119 sge_off = sge->offset + off;
120 sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
121 } else {
122 return -ENOSPC;
123 }
124
125 off = 0;
126 len -= sge_len;
127 sk_mem_charge(sk, sge_len);
128 sk_msg_iter_var_next(i);
129 if (i == src->sg.end && len)
130 return -ENOSPC;
131 sge = sk_msg_elem(src, i);
132 }
133
134 return 0;
135}
136EXPORT_SYMBOL_GPL(sk_msg_clone);
137
138void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
139{
140 int i = msg->sg.start;
141
142 do {
143 struct scatterlist *sge = sk_msg_elem(msg, i);
144
145 if (bytes < sge->length) {
146 sge->length -= bytes;
147 sge->offset += bytes;
148 sk_mem_uncharge(sk, bytes);
149 break;
150 }
151
152 sk_mem_uncharge(sk, sge->length);
153 bytes -= sge->length;
154 sge->length = 0;
155 sge->offset = 0;
156 sk_msg_iter_var_next(i);
157 } while (bytes && i != msg->sg.end);
158 msg->sg.start = i;
159}
160EXPORT_SYMBOL_GPL(sk_msg_return_zero);
161
162void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
163{
164 int i = msg->sg.start;
165
166 do {
167 struct scatterlist *sge = &msg->sg.data[i];
168 int uncharge = (bytes < sge->length) ? bytes : sge->length;
169
170 sk_mem_uncharge(sk, uncharge);
171 bytes -= uncharge;
172 sk_msg_iter_var_next(i);
173 } while (i != msg->sg.end);
174}
175EXPORT_SYMBOL_GPL(sk_msg_return);
176
177static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
178 bool charge)
179{
180 struct scatterlist *sge = sk_msg_elem(msg, i);
181 u32 len = sge->length;
182
183 /* When the skb owns the memory we free it from consume_skb path. */
184 if (!msg->skb) {
185 if (charge)
186 sk_mem_uncharge(sk, len);
187 put_page(sg_page(sge));
188 }
189 memset(sge, 0, sizeof(*sge));
190 return len;
191}
192
193static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
194 bool charge)
195{
196 struct scatterlist *sge = sk_msg_elem(msg, i);
197 int freed = 0;
198
199 while (msg->sg.size) {
200 msg->sg.size -= sge->length;
201 freed += sk_msg_free_elem(sk, msg, i, charge);
202 sk_msg_iter_var_next(i);
203 sk_msg_check_to_free(msg, i, msg->sg.size);
204 sge = sk_msg_elem(msg, i);
205 }
206 consume_skb(msg->skb);
207 sk_msg_init(msg);
208 return freed;
209}
210
211int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
212{
213 return __sk_msg_free(sk, msg, msg->sg.start, false);
214}
215EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
216
217int sk_msg_free(struct sock *sk, struct sk_msg *msg)
218{
219 return __sk_msg_free(sk, msg, msg->sg.start, true);
220}
221EXPORT_SYMBOL_GPL(sk_msg_free);
222
223static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
224 u32 bytes, bool charge)
225{
226 struct scatterlist *sge;
227 u32 i = msg->sg.start;
228
229 while (bytes) {
230 sge = sk_msg_elem(msg, i);
231 if (!sge->length)
232 break;
233 if (bytes < sge->length) {
234 if (charge)
235 sk_mem_uncharge(sk, bytes);
236 sge->length -= bytes;
237 sge->offset += bytes;
238 msg->sg.size -= bytes;
239 break;
240 }
241
242 msg->sg.size -= sge->length;
243 bytes -= sge->length;
244 sk_msg_free_elem(sk, msg, i, charge);
245 sk_msg_iter_var_next(i);
246 sk_msg_check_to_free(msg, i, bytes);
247 }
248 msg->sg.start = i;
249}
250
251void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
252{
253 __sk_msg_free_partial(sk, msg, bytes, true);
254}
255EXPORT_SYMBOL_GPL(sk_msg_free_partial);
256
257void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
258 u32 bytes)
259{
260 __sk_msg_free_partial(sk, msg, bytes, false);
261}
262
263void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
264{
265 int trim = msg->sg.size - len;
266 u32 i = msg->sg.end;
267
268 if (trim <= 0) {
269 WARN_ON(trim < 0);
270 return;
271 }
272
273 sk_msg_iter_var_prev(i);
274 msg->sg.size = len;
275 while (msg->sg.data[i].length &&
276 trim >= msg->sg.data[i].length) {
277 trim -= msg->sg.data[i].length;
278 sk_msg_free_elem(sk, msg, i, true);
279 sk_msg_iter_var_prev(i);
280 if (!trim)
281 goto out;
282 }
283
284 msg->sg.data[i].length -= trim;
285 sk_mem_uncharge(sk, trim);
286 /* Adjust copybreak if it falls into the trimmed part of last buf */
287 if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
288 msg->sg.copybreak = msg->sg.data[i].length;
289out:
290 sk_msg_iter_var_next(i);
291 msg->sg.end = i;
292
293 /* If we trim data a full sg elem before curr pointer update
294 * copybreak and current so that any future copy operations
295 * start at new copy location.
296 * However trimed data that has not yet been used in a copy op
297 * does not require an update.
298 */
299 if (!msg->sg.size) {
300 msg->sg.curr = msg->sg.start;
301 msg->sg.copybreak = 0;
302 } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
303 sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
304 sk_msg_iter_var_prev(i);
305 msg->sg.curr = i;
306 msg->sg.copybreak = msg->sg.data[i].length;
307 }
308}
309EXPORT_SYMBOL_GPL(sk_msg_trim);
310
311int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
312 struct sk_msg *msg, u32 bytes)
313{
314 int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
315 const int to_max_pages = MAX_MSG_FRAGS;
316 struct page *pages[MAX_MSG_FRAGS];
317 ssize_t orig, copied, use, offset;
318
319 orig = msg->sg.size;
320 while (bytes > 0) {
321 i = 0;
322 maxpages = to_max_pages - num_elems;
323 if (maxpages == 0) {
324 ret = -EFAULT;
325 goto out;
326 }
327
328 copied = iov_iter_get_pages2(from, pages, bytes, maxpages,
329 &offset);
330 if (copied <= 0) {
331 ret = -EFAULT;
332 goto out;
333 }
334
335 bytes -= copied;
336 msg->sg.size += copied;
337
338 while (copied) {
339 use = min_t(int, copied, PAGE_SIZE - offset);
340 sg_set_page(&msg->sg.data[msg->sg.end],
341 pages[i], use, offset);
342 sg_unmark_end(&msg->sg.data[msg->sg.end]);
343 sk_mem_charge(sk, use);
344
345 offset = 0;
346 copied -= use;
347 sk_msg_iter_next(msg, end);
348 num_elems++;
349 i++;
350 }
351 /* When zerocopy is mixed with sk_msg_*copy* operations we
352 * may have a copybreak set in this case clear and prefer
353 * zerocopy remainder when possible.
354 */
355 msg->sg.copybreak = 0;
356 msg->sg.curr = msg->sg.end;
357 }
358out:
359 /* Revert iov_iter updates, msg will need to use 'trim' later if it
360 * also needs to be cleared.
361 */
362 if (ret)
363 iov_iter_revert(from, msg->sg.size - orig);
364 return ret;
365}
366EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
367
368int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
369 struct sk_msg *msg, u32 bytes)
370{
371 int ret = -ENOSPC, i = msg->sg.curr;
372 struct scatterlist *sge;
373 u32 copy, buf_size;
374 void *to;
375
376 do {
377 sge = sk_msg_elem(msg, i);
378 /* This is possible if a trim operation shrunk the buffer */
379 if (msg->sg.copybreak >= sge->length) {
380 msg->sg.copybreak = 0;
381 sk_msg_iter_var_next(i);
382 if (i == msg->sg.end)
383 break;
384 sge = sk_msg_elem(msg, i);
385 }
386
387 buf_size = sge->length - msg->sg.copybreak;
388 copy = (buf_size > bytes) ? bytes : buf_size;
389 to = sg_virt(sge) + msg->sg.copybreak;
390 msg->sg.copybreak += copy;
391 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
392 ret = copy_from_iter_nocache(to, copy, from);
393 else
394 ret = copy_from_iter(to, copy, from);
395 if (ret != copy) {
396 ret = -EFAULT;
397 goto out;
398 }
399 bytes -= copy;
400 if (!bytes)
401 break;
402 msg->sg.copybreak = 0;
403 sk_msg_iter_var_next(i);
404 } while (i != msg->sg.end);
405out:
406 msg->sg.curr = i;
407 return ret;
408}
409EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
410
411/* Receive sk_msg from psock->ingress_msg to @msg. */
412int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
413 int len, int flags)
414{
415 struct iov_iter *iter = &msg->msg_iter;
416 int peek = flags & MSG_PEEK;
417 struct sk_msg *msg_rx;
418 int i, copied = 0;
419
420 msg_rx = sk_psock_peek_msg(psock);
421 while (copied != len) {
422 struct scatterlist *sge;
423
424 if (unlikely(!msg_rx))
425 break;
426
427 i = msg_rx->sg.start;
428 do {
429 struct page *page;
430 int copy;
431
432 sge = sk_msg_elem(msg_rx, i);
433 copy = sge->length;
434 page = sg_page(sge);
435 if (copied + copy > len)
436 copy = len - copied;
437 copy = copy_page_to_iter(page, sge->offset, copy, iter);
438 if (!copy) {
439 copied = copied ? copied : -EFAULT;
440 goto out;
441 }
442
443 copied += copy;
444 if (likely(!peek)) {
445 sge->offset += copy;
446 sge->length -= copy;
447 if (!msg_rx->skb)
448 sk_mem_uncharge(sk, copy);
449 msg_rx->sg.size -= copy;
450
451 if (!sge->length) {
452 sk_msg_iter_var_next(i);
453 if (!msg_rx->skb)
454 put_page(page);
455 }
456 } else {
457 /* Lets not optimize peek case if copy_page_to_iter
458 * didn't copy the entire length lets just break.
459 */
460 if (copy != sge->length)
461 goto out;
462 sk_msg_iter_var_next(i);
463 }
464
465 if (copied == len)
466 break;
467 } while ((i != msg_rx->sg.end) && !sg_is_last(sge));
468
469 if (unlikely(peek)) {
470 msg_rx = sk_psock_next_msg(psock, msg_rx);
471 if (!msg_rx)
472 break;
473 continue;
474 }
475
476 msg_rx->sg.start = i;
477 if (!sge->length && (i == msg_rx->sg.end || sg_is_last(sge))) {
478 msg_rx = sk_psock_dequeue_msg(psock);
479 kfree_sk_msg(msg_rx);
480 }
481 msg_rx = sk_psock_peek_msg(psock);
482 }
483out:
484 return copied;
485}
486EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
487
488bool sk_msg_is_readable(struct sock *sk)
489{
490 struct sk_psock *psock;
491 bool empty = true;
492
493 rcu_read_lock();
494 psock = sk_psock(sk);
495 if (likely(psock))
496 empty = list_empty(&psock->ingress_msg);
497 rcu_read_unlock();
498 return !empty;
499}
500EXPORT_SYMBOL_GPL(sk_msg_is_readable);
501
502static struct sk_msg *alloc_sk_msg(gfp_t gfp)
503{
504 struct sk_msg *msg;
505
506 msg = kzalloc(sizeof(*msg), gfp | __GFP_NOWARN);
507 if (unlikely(!msg))
508 return NULL;
509 sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
510 return msg;
511}
512
513static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
514 struct sk_buff *skb)
515{
516 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
517 return NULL;
518
519 if (!sk_rmem_schedule(sk, skb, skb->truesize))
520 return NULL;
521
522 return alloc_sk_msg(GFP_KERNEL);
523}
524
525static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
526 u32 off, u32 len,
527 struct sk_psock *psock,
528 struct sock *sk,
529 struct sk_msg *msg)
530{
531 int num_sge, copied;
532
533 num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
534 if (num_sge < 0) {
535 /* skb linearize may fail with ENOMEM, but lets simply try again
536 * later if this happens. Under memory pressure we don't want to
537 * drop the skb. We need to linearize the skb so that the mapping
538 * in skb_to_sgvec can not error.
539 */
540 if (skb_linearize(skb))
541 return -EAGAIN;
542
543 num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
544 if (unlikely(num_sge < 0))
545 return num_sge;
546 }
547
548 copied = len;
549 msg->sg.start = 0;
550 msg->sg.size = copied;
551 msg->sg.end = num_sge;
552 msg->skb = skb;
553
554 sk_psock_queue_msg(psock, msg);
555 sk_psock_data_ready(sk, psock);
556 return copied;
557}
558
559static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
560 u32 off, u32 len);
561
562static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
563 u32 off, u32 len)
564{
565 struct sock *sk = psock->sk;
566 struct sk_msg *msg;
567 int err;
568
569 /* If we are receiving on the same sock skb->sk is already assigned,
570 * skip memory accounting and owner transition seeing it already set
571 * correctly.
572 */
573 if (unlikely(skb->sk == sk))
574 return sk_psock_skb_ingress_self(psock, skb, off, len);
575 msg = sk_psock_create_ingress_msg(sk, skb);
576 if (!msg)
577 return -EAGAIN;
578
579 /* This will transition ownership of the data from the socket where
580 * the BPF program was run initiating the redirect to the socket
581 * we will eventually receive this data on. The data will be released
582 * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
583 * into user buffers.
584 */
585 skb_set_owner_r(skb, sk);
586 err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
587 if (err < 0)
588 kfree(msg);
589 return err;
590}
591
592/* Puts an skb on the ingress queue of the socket already assigned to the
593 * skb. In this case we do not need to check memory limits or skb_set_owner_r
594 * because the skb is already accounted for here.
595 */
596static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
597 u32 off, u32 len)
598{
599 struct sk_msg *msg = alloc_sk_msg(GFP_ATOMIC);
600 struct sock *sk = psock->sk;
601 int err;
602
603 if (unlikely(!msg))
604 return -EAGAIN;
605 skb_set_owner_r(skb, sk);
606 err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
607 if (err < 0)
608 kfree(msg);
609 return err;
610}
611
612static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
613 u32 off, u32 len, bool ingress)
614{
615 int err = 0;
616
617 if (!ingress) {
618 if (!sock_writeable(psock->sk))
619 return -EAGAIN;
620 return skb_send_sock(psock->sk, skb, off, len);
621 }
622 skb_get(skb);
623 err = sk_psock_skb_ingress(psock, skb, off, len);
624 if (err < 0)
625 kfree_skb(skb);
626 return err;
627}
628
629static void sk_psock_skb_state(struct sk_psock *psock,
630 struct sk_psock_work_state *state,
631 int len, int off)
632{
633 spin_lock_bh(&psock->ingress_lock);
634 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
635 state->len = len;
636 state->off = off;
637 }
638 spin_unlock_bh(&psock->ingress_lock);
639}
640
641static void sk_psock_backlog(struct work_struct *work)
642{
643 struct delayed_work *dwork = to_delayed_work(work);
644 struct sk_psock *psock = container_of(dwork, struct sk_psock, work);
645 struct sk_psock_work_state *state = &psock->work_state;
646 struct sk_buff *skb = NULL;
647 u32 len = 0, off = 0;
648 bool ingress;
649 int ret;
650
651 mutex_lock(&psock->work_mutex);
652 if (unlikely(state->len)) {
653 len = state->len;
654 off = state->off;
655 }
656
657 while ((skb = skb_peek(&psock->ingress_skb))) {
658 len = skb->len;
659 off = 0;
660 if (skb_bpf_strparser(skb)) {
661 struct strp_msg *stm = strp_msg(skb);
662
663 off = stm->offset;
664 len = stm->full_len;
665 }
666 ingress = skb_bpf_ingress(skb);
667 skb_bpf_redirect_clear(skb);
668 do {
669 ret = -EIO;
670 if (!sock_flag(psock->sk, SOCK_DEAD))
671 ret = sk_psock_handle_skb(psock, skb, off,
672 len, ingress);
673 if (ret <= 0) {
674 if (ret == -EAGAIN) {
675 sk_psock_skb_state(psock, state, len, off);
676
677 /* Delay slightly to prioritize any
678 * other work that might be here.
679 */
680 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
681 schedule_delayed_work(&psock->work, 1);
682 goto end;
683 }
684 /* Hard errors break pipe and stop xmit. */
685 sk_psock_report_error(psock, ret ? -ret : EPIPE);
686 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
687 goto end;
688 }
689 off += ret;
690 len -= ret;
691 } while (len);
692
693 skb = skb_dequeue(&psock->ingress_skb);
694 kfree_skb(skb);
695 }
696end:
697 mutex_unlock(&psock->work_mutex);
698}
699
700struct sk_psock *sk_psock_init(struct sock *sk, int node)
701{
702 struct sk_psock *psock;
703 struct proto *prot;
704
705 write_lock_bh(&sk->sk_callback_lock);
706
707 if (sk_is_inet(sk) && inet_csk_has_ulp(sk)) {
708 psock = ERR_PTR(-EINVAL);
709 goto out;
710 }
711
712 if (sk->sk_user_data) {
713 psock = ERR_PTR(-EBUSY);
714 goto out;
715 }
716
717 psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
718 if (!psock) {
719 psock = ERR_PTR(-ENOMEM);
720 goto out;
721 }
722
723 prot = READ_ONCE(sk->sk_prot);
724 psock->sk = sk;
725 psock->eval = __SK_NONE;
726 psock->sk_proto = prot;
727 psock->saved_unhash = prot->unhash;
728 psock->saved_destroy = prot->destroy;
729 psock->saved_close = prot->close;
730 psock->saved_write_space = sk->sk_write_space;
731
732 INIT_LIST_HEAD(&psock->link);
733 spin_lock_init(&psock->link_lock);
734
735 INIT_DELAYED_WORK(&psock->work, sk_psock_backlog);
736 mutex_init(&psock->work_mutex);
737 INIT_LIST_HEAD(&psock->ingress_msg);
738 spin_lock_init(&psock->ingress_lock);
739 skb_queue_head_init(&psock->ingress_skb);
740
741 sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
742 refcount_set(&psock->refcnt, 1);
743
744 __rcu_assign_sk_user_data_with_flags(sk, psock,
745 SK_USER_DATA_NOCOPY |
746 SK_USER_DATA_PSOCK);
747 sock_hold(sk);
748
749out:
750 write_unlock_bh(&sk->sk_callback_lock);
751 return psock;
752}
753EXPORT_SYMBOL_GPL(sk_psock_init);
754
755struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
756{
757 struct sk_psock_link *link;
758
759 spin_lock_bh(&psock->link_lock);
760 link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
761 list);
762 if (link)
763 list_del(&link->list);
764 spin_unlock_bh(&psock->link_lock);
765 return link;
766}
767
768static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
769{
770 struct sk_msg *msg, *tmp;
771
772 list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
773 list_del(&msg->list);
774 sk_msg_free(psock->sk, msg);
775 kfree(msg);
776 }
777}
778
779static void __sk_psock_zap_ingress(struct sk_psock *psock)
780{
781 struct sk_buff *skb;
782
783 while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
784 skb_bpf_redirect_clear(skb);
785 sock_drop(psock->sk, skb);
786 }
787 __sk_psock_purge_ingress_msg(psock);
788}
789
790static void sk_psock_link_destroy(struct sk_psock *psock)
791{
792 struct sk_psock_link *link, *tmp;
793
794 list_for_each_entry_safe(link, tmp, &psock->link, list) {
795 list_del(&link->list);
796 sk_psock_free_link(link);
797 }
798}
799
800void sk_psock_stop(struct sk_psock *psock)
801{
802 spin_lock_bh(&psock->ingress_lock);
803 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
804 sk_psock_cork_free(psock);
805 spin_unlock_bh(&psock->ingress_lock);
806}
807
808static void sk_psock_done_strp(struct sk_psock *psock);
809
810static void sk_psock_destroy(struct work_struct *work)
811{
812 struct sk_psock *psock = container_of(to_rcu_work(work),
813 struct sk_psock, rwork);
814 /* No sk_callback_lock since already detached. */
815
816 sk_psock_done_strp(psock);
817
818 cancel_delayed_work_sync(&psock->work);
819 __sk_psock_zap_ingress(psock);
820 mutex_destroy(&psock->work_mutex);
821
822 psock_progs_drop(&psock->progs);
823
824 sk_psock_link_destroy(psock);
825 sk_psock_cork_free(psock);
826
827 if (psock->sk_redir)
828 sock_put(psock->sk_redir);
829 if (psock->sk_pair)
830 sock_put(psock->sk_pair);
831 sock_put(psock->sk);
832 kfree(psock);
833}
834
835void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
836{
837 write_lock_bh(&sk->sk_callback_lock);
838 sk_psock_restore_proto(sk, psock);
839 rcu_assign_sk_user_data(sk, NULL);
840 if (psock->progs.stream_parser)
841 sk_psock_stop_strp(sk, psock);
842 else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
843 sk_psock_stop_verdict(sk, psock);
844 write_unlock_bh(&sk->sk_callback_lock);
845
846 sk_psock_stop(psock);
847
848 INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
849 queue_rcu_work(system_wq, &psock->rwork);
850}
851EXPORT_SYMBOL_GPL(sk_psock_drop);
852
853static int sk_psock_map_verd(int verdict, bool redir)
854{
855 switch (verdict) {
856 case SK_PASS:
857 return redir ? __SK_REDIRECT : __SK_PASS;
858 case SK_DROP:
859 default:
860 break;
861 }
862
863 return __SK_DROP;
864}
865
866int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
867 struct sk_msg *msg)
868{
869 struct bpf_prog *prog;
870 int ret;
871
872 rcu_read_lock();
873 prog = READ_ONCE(psock->progs.msg_parser);
874 if (unlikely(!prog)) {
875 ret = __SK_PASS;
876 goto out;
877 }
878
879 sk_msg_compute_data_pointers(msg);
880 msg->sk = sk;
881 ret = bpf_prog_run_pin_on_cpu(prog, msg);
882 ret = sk_psock_map_verd(ret, msg->sk_redir);
883 psock->apply_bytes = msg->apply_bytes;
884 if (ret == __SK_REDIRECT) {
885 if (psock->sk_redir) {
886 sock_put(psock->sk_redir);
887 psock->sk_redir = NULL;
888 }
889 if (!msg->sk_redir) {
890 ret = __SK_DROP;
891 goto out;
892 }
893 psock->redir_ingress = sk_msg_to_ingress(msg);
894 psock->sk_redir = msg->sk_redir;
895 sock_hold(psock->sk_redir);
896 }
897out:
898 rcu_read_unlock();
899 return ret;
900}
901EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
902
903static int sk_psock_skb_redirect(struct sk_psock *from, struct sk_buff *skb)
904{
905 struct sk_psock *psock_other;
906 struct sock *sk_other;
907
908 sk_other = skb_bpf_redirect_fetch(skb);
909 /* This error is a buggy BPF program, it returned a redirect
910 * return code, but then didn't set a redirect interface.
911 */
912 if (unlikely(!sk_other)) {
913 skb_bpf_redirect_clear(skb);
914 sock_drop(from->sk, skb);
915 return -EIO;
916 }
917 psock_other = sk_psock(sk_other);
918 /* This error indicates the socket is being torn down or had another
919 * error that caused the pipe to break. We can't send a packet on
920 * a socket that is in this state so we drop the skb.
921 */
922 if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
923 skb_bpf_redirect_clear(skb);
924 sock_drop(from->sk, skb);
925 return -EIO;
926 }
927 spin_lock_bh(&psock_other->ingress_lock);
928 if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
929 spin_unlock_bh(&psock_other->ingress_lock);
930 skb_bpf_redirect_clear(skb);
931 sock_drop(from->sk, skb);
932 return -EIO;
933 }
934
935 skb_queue_tail(&psock_other->ingress_skb, skb);
936 schedule_delayed_work(&psock_other->work, 0);
937 spin_unlock_bh(&psock_other->ingress_lock);
938 return 0;
939}
940
941static void sk_psock_tls_verdict_apply(struct sk_buff *skb,
942 struct sk_psock *from, int verdict)
943{
944 switch (verdict) {
945 case __SK_REDIRECT:
946 sk_psock_skb_redirect(from, skb);
947 break;
948 case __SK_PASS:
949 case __SK_DROP:
950 default:
951 break;
952 }
953}
954
955int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
956{
957 struct bpf_prog *prog;
958 int ret = __SK_PASS;
959
960 rcu_read_lock();
961 prog = READ_ONCE(psock->progs.stream_verdict);
962 if (likely(prog)) {
963 skb->sk = psock->sk;
964 skb_dst_drop(skb);
965 skb_bpf_redirect_clear(skb);
966 ret = bpf_prog_run_pin_on_cpu(prog, skb);
967 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
968 skb->sk = NULL;
969 }
970 sk_psock_tls_verdict_apply(skb, psock, ret);
971 rcu_read_unlock();
972 return ret;
973}
974EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
975
976static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
977 int verdict)
978{
979 struct sock *sk_other;
980 int err = 0;
981 u32 len, off;
982
983 switch (verdict) {
984 case __SK_PASS:
985 err = -EIO;
986 sk_other = psock->sk;
987 if (sock_flag(sk_other, SOCK_DEAD) ||
988 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
989 goto out_free;
990
991 skb_bpf_set_ingress(skb);
992
993 /* If the queue is empty then we can submit directly
994 * into the msg queue. If its not empty we have to
995 * queue work otherwise we may get OOO data. Otherwise,
996 * if sk_psock_skb_ingress errors will be handled by
997 * retrying later from workqueue.
998 */
999 if (skb_queue_empty(&psock->ingress_skb)) {
1000 len = skb->len;
1001 off = 0;
1002 if (skb_bpf_strparser(skb)) {
1003 struct strp_msg *stm = strp_msg(skb);
1004
1005 off = stm->offset;
1006 len = stm->full_len;
1007 }
1008 err = sk_psock_skb_ingress_self(psock, skb, off, len);
1009 }
1010 if (err < 0) {
1011 spin_lock_bh(&psock->ingress_lock);
1012 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
1013 skb_queue_tail(&psock->ingress_skb, skb);
1014 schedule_delayed_work(&psock->work, 0);
1015 err = 0;
1016 }
1017 spin_unlock_bh(&psock->ingress_lock);
1018 if (err < 0)
1019 goto out_free;
1020 }
1021 break;
1022 case __SK_REDIRECT:
1023 tcp_eat_skb(psock->sk, skb);
1024 err = sk_psock_skb_redirect(psock, skb);
1025 break;
1026 case __SK_DROP:
1027 default:
1028out_free:
1029 skb_bpf_redirect_clear(skb);
1030 tcp_eat_skb(psock->sk, skb);
1031 sock_drop(psock->sk, skb);
1032 }
1033
1034 return err;
1035}
1036
1037static void sk_psock_write_space(struct sock *sk)
1038{
1039 struct sk_psock *psock;
1040 void (*write_space)(struct sock *sk) = NULL;
1041
1042 rcu_read_lock();
1043 psock = sk_psock(sk);
1044 if (likely(psock)) {
1045 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
1046 schedule_delayed_work(&psock->work, 0);
1047 write_space = psock->saved_write_space;
1048 }
1049 rcu_read_unlock();
1050 if (write_space)
1051 write_space(sk);
1052}
1053
1054#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1055static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
1056{
1057 struct sk_psock *psock;
1058 struct bpf_prog *prog;
1059 int ret = __SK_DROP;
1060 struct sock *sk;
1061
1062 rcu_read_lock();
1063 sk = strp->sk;
1064 psock = sk_psock(sk);
1065 if (unlikely(!psock)) {
1066 sock_drop(sk, skb);
1067 goto out;
1068 }
1069 prog = READ_ONCE(psock->progs.stream_verdict);
1070 if (likely(prog)) {
1071 skb->sk = sk;
1072 skb_dst_drop(skb);
1073 skb_bpf_redirect_clear(skb);
1074 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1075 skb_bpf_set_strparser(skb);
1076 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1077 skb->sk = NULL;
1078 }
1079 sk_psock_verdict_apply(psock, skb, ret);
1080out:
1081 rcu_read_unlock();
1082}
1083
1084static int sk_psock_strp_read_done(struct strparser *strp, int err)
1085{
1086 return err;
1087}
1088
1089static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
1090{
1091 struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1092 struct bpf_prog *prog;
1093 int ret = skb->len;
1094
1095 rcu_read_lock();
1096 prog = READ_ONCE(psock->progs.stream_parser);
1097 if (likely(prog)) {
1098 skb->sk = psock->sk;
1099 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1100 skb->sk = NULL;
1101 }
1102 rcu_read_unlock();
1103 return ret;
1104}
1105
1106/* Called with socket lock held. */
1107static void sk_psock_strp_data_ready(struct sock *sk)
1108{
1109 struct sk_psock *psock;
1110
1111 trace_sk_data_ready(sk);
1112
1113 rcu_read_lock();
1114 psock = sk_psock(sk);
1115 if (likely(psock)) {
1116 if (tls_sw_has_ctx_rx(sk)) {
1117 psock->saved_data_ready(sk);
1118 } else {
1119 write_lock_bh(&sk->sk_callback_lock);
1120 strp_data_ready(&psock->strp);
1121 write_unlock_bh(&sk->sk_callback_lock);
1122 }
1123 }
1124 rcu_read_unlock();
1125}
1126
1127int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
1128{
1129 int ret;
1130
1131 static const struct strp_callbacks cb = {
1132 .rcv_msg = sk_psock_strp_read,
1133 .read_sock_done = sk_psock_strp_read_done,
1134 .parse_msg = sk_psock_strp_parse,
1135 };
1136
1137 ret = strp_init(&psock->strp, sk, &cb);
1138 if (!ret)
1139 sk_psock_set_state(psock, SK_PSOCK_RX_STRP_ENABLED);
1140
1141 return ret;
1142}
1143
1144void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
1145{
1146 if (psock->saved_data_ready)
1147 return;
1148
1149 psock->saved_data_ready = sk->sk_data_ready;
1150 sk->sk_data_ready = sk_psock_strp_data_ready;
1151 sk->sk_write_space = sk_psock_write_space;
1152}
1153
1154void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
1155{
1156 psock_set_prog(&psock->progs.stream_parser, NULL);
1157
1158 if (!psock->saved_data_ready)
1159 return;
1160
1161 sk->sk_data_ready = psock->saved_data_ready;
1162 psock->saved_data_ready = NULL;
1163 strp_stop(&psock->strp);
1164}
1165
1166static void sk_psock_done_strp(struct sk_psock *psock)
1167{
1168 /* Parser has been stopped */
1169 if (sk_psock_test_state(psock, SK_PSOCK_RX_STRP_ENABLED))
1170 strp_done(&psock->strp);
1171}
1172#else
1173static void sk_psock_done_strp(struct sk_psock *psock)
1174{
1175}
1176#endif /* CONFIG_BPF_STREAM_PARSER */
1177
1178static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
1179{
1180 struct sk_psock *psock;
1181 struct bpf_prog *prog;
1182 int ret = __SK_DROP;
1183 int len = skb->len;
1184
1185 rcu_read_lock();
1186 psock = sk_psock(sk);
1187 if (unlikely(!psock)) {
1188 len = 0;
1189 tcp_eat_skb(sk, skb);
1190 sock_drop(sk, skb);
1191 goto out;
1192 }
1193 prog = READ_ONCE(psock->progs.stream_verdict);
1194 if (!prog)
1195 prog = READ_ONCE(psock->progs.skb_verdict);
1196 if (likely(prog)) {
1197 skb_dst_drop(skb);
1198 skb_bpf_redirect_clear(skb);
1199 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1200 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1201 }
1202 ret = sk_psock_verdict_apply(psock, skb, ret);
1203 if (ret < 0)
1204 len = ret;
1205out:
1206 rcu_read_unlock();
1207 return len;
1208}
1209
1210static void sk_psock_verdict_data_ready(struct sock *sk)
1211{
1212 struct socket *sock = sk->sk_socket;
1213 const struct proto_ops *ops;
1214 int copied;
1215
1216 trace_sk_data_ready(sk);
1217
1218 if (unlikely(!sock))
1219 return;
1220 ops = READ_ONCE(sock->ops);
1221 if (!ops || !ops->read_skb)
1222 return;
1223 copied = ops->read_skb(sk, sk_psock_verdict_recv);
1224 if (copied >= 0) {
1225 struct sk_psock *psock;
1226
1227 rcu_read_lock();
1228 psock = sk_psock(sk);
1229 if (psock) {
1230 read_lock_bh(&sk->sk_callback_lock);
1231 sk_psock_data_ready(sk, psock);
1232 read_unlock_bh(&sk->sk_callback_lock);
1233 }
1234 rcu_read_unlock();
1235 }
1236}
1237
1238void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1239{
1240 if (psock->saved_data_ready)
1241 return;
1242
1243 psock->saved_data_ready = sk->sk_data_ready;
1244 sk->sk_data_ready = sk_psock_verdict_data_ready;
1245 sk->sk_write_space = sk_psock_write_space;
1246}
1247
1248void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1249{
1250 psock_set_prog(&psock->progs.stream_verdict, NULL);
1251 psock_set_prog(&psock->progs.skb_verdict, NULL);
1252
1253 if (!psock->saved_data_ready)
1254 return;
1255
1256 sk->sk_data_ready = psock->saved_data_ready;
1257 psock->saved_data_ready = NULL;
1258}
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/skbuff.h>
6#include <linux/scatterlist.h>
7
8#include <net/sock.h>
9#include <net/tcp.h>
10
11static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
12{
13 if (msg->sg.end > msg->sg.start &&
14 elem_first_coalesce < msg->sg.end)
15 return true;
16
17 if (msg->sg.end < msg->sg.start &&
18 (elem_first_coalesce > msg->sg.start ||
19 elem_first_coalesce < msg->sg.end))
20 return true;
21
22 return false;
23}
24
25int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
26 int elem_first_coalesce)
27{
28 struct page_frag *pfrag = sk_page_frag(sk);
29 int ret = 0;
30
31 len -= msg->sg.size;
32 while (len > 0) {
33 struct scatterlist *sge;
34 u32 orig_offset;
35 int use, i;
36
37 if (!sk_page_frag_refill(sk, pfrag))
38 return -ENOMEM;
39
40 orig_offset = pfrag->offset;
41 use = min_t(int, len, pfrag->size - orig_offset);
42 if (!sk_wmem_schedule(sk, use))
43 return -ENOMEM;
44
45 i = msg->sg.end;
46 sk_msg_iter_var_prev(i);
47 sge = &msg->sg.data[i];
48
49 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
50 sg_page(sge) == pfrag->page &&
51 sge->offset + sge->length == orig_offset) {
52 sge->length += use;
53 } else {
54 if (sk_msg_full(msg)) {
55 ret = -ENOSPC;
56 break;
57 }
58
59 sge = &msg->sg.data[msg->sg.end];
60 sg_unmark_end(sge);
61 sg_set_page(sge, pfrag->page, use, orig_offset);
62 get_page(pfrag->page);
63 sk_msg_iter_next(msg, end);
64 }
65
66 sk_mem_charge(sk, use);
67 msg->sg.size += use;
68 pfrag->offset += use;
69 len -= use;
70 }
71
72 return ret;
73}
74EXPORT_SYMBOL_GPL(sk_msg_alloc);
75
76int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
77 u32 off, u32 len)
78{
79 int i = src->sg.start;
80 struct scatterlist *sge = sk_msg_elem(src, i);
81 struct scatterlist *sgd = NULL;
82 u32 sge_len, sge_off;
83
84 while (off) {
85 if (sge->length > off)
86 break;
87 off -= sge->length;
88 sk_msg_iter_var_next(i);
89 if (i == src->sg.end && off)
90 return -ENOSPC;
91 sge = sk_msg_elem(src, i);
92 }
93
94 while (len) {
95 sge_len = sge->length - off;
96 if (sge_len > len)
97 sge_len = len;
98
99 if (dst->sg.end)
100 sgd = sk_msg_elem(dst, dst->sg.end - 1);
101
102 if (sgd &&
103 (sg_page(sge) == sg_page(sgd)) &&
104 (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
105 sgd->length += sge_len;
106 dst->sg.size += sge_len;
107 } else if (!sk_msg_full(dst)) {
108 sge_off = sge->offset + off;
109 sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
110 } else {
111 return -ENOSPC;
112 }
113
114 off = 0;
115 len -= sge_len;
116 sk_mem_charge(sk, sge_len);
117 sk_msg_iter_var_next(i);
118 if (i == src->sg.end && len)
119 return -ENOSPC;
120 sge = sk_msg_elem(src, i);
121 }
122
123 return 0;
124}
125EXPORT_SYMBOL_GPL(sk_msg_clone);
126
127void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
128{
129 int i = msg->sg.start;
130
131 do {
132 struct scatterlist *sge = sk_msg_elem(msg, i);
133
134 if (bytes < sge->length) {
135 sge->length -= bytes;
136 sge->offset += bytes;
137 sk_mem_uncharge(sk, bytes);
138 break;
139 }
140
141 sk_mem_uncharge(sk, sge->length);
142 bytes -= sge->length;
143 sge->length = 0;
144 sge->offset = 0;
145 sk_msg_iter_var_next(i);
146 } while (bytes && i != msg->sg.end);
147 msg->sg.start = i;
148}
149EXPORT_SYMBOL_GPL(sk_msg_return_zero);
150
151void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
152{
153 int i = msg->sg.start;
154
155 do {
156 struct scatterlist *sge = &msg->sg.data[i];
157 int uncharge = (bytes < sge->length) ? bytes : sge->length;
158
159 sk_mem_uncharge(sk, uncharge);
160 bytes -= uncharge;
161 sk_msg_iter_var_next(i);
162 } while (i != msg->sg.end);
163}
164EXPORT_SYMBOL_GPL(sk_msg_return);
165
166static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
167 bool charge)
168{
169 struct scatterlist *sge = sk_msg_elem(msg, i);
170 u32 len = sge->length;
171
172 if (charge)
173 sk_mem_uncharge(sk, len);
174 if (!msg->skb)
175 put_page(sg_page(sge));
176 memset(sge, 0, sizeof(*sge));
177 return len;
178}
179
180static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
181 bool charge)
182{
183 struct scatterlist *sge = sk_msg_elem(msg, i);
184 int freed = 0;
185
186 while (msg->sg.size) {
187 msg->sg.size -= sge->length;
188 freed += sk_msg_free_elem(sk, msg, i, charge);
189 sk_msg_iter_var_next(i);
190 sk_msg_check_to_free(msg, i, msg->sg.size);
191 sge = sk_msg_elem(msg, i);
192 }
193 consume_skb(msg->skb);
194 sk_msg_init(msg);
195 return freed;
196}
197
198int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
199{
200 return __sk_msg_free(sk, msg, msg->sg.start, false);
201}
202EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
203
204int sk_msg_free(struct sock *sk, struct sk_msg *msg)
205{
206 return __sk_msg_free(sk, msg, msg->sg.start, true);
207}
208EXPORT_SYMBOL_GPL(sk_msg_free);
209
210static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
211 u32 bytes, bool charge)
212{
213 struct scatterlist *sge;
214 u32 i = msg->sg.start;
215
216 while (bytes) {
217 sge = sk_msg_elem(msg, i);
218 if (!sge->length)
219 break;
220 if (bytes < sge->length) {
221 if (charge)
222 sk_mem_uncharge(sk, bytes);
223 sge->length -= bytes;
224 sge->offset += bytes;
225 msg->sg.size -= bytes;
226 break;
227 }
228
229 msg->sg.size -= sge->length;
230 bytes -= sge->length;
231 sk_msg_free_elem(sk, msg, i, charge);
232 sk_msg_iter_var_next(i);
233 sk_msg_check_to_free(msg, i, bytes);
234 }
235 msg->sg.start = i;
236}
237
238void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
239{
240 __sk_msg_free_partial(sk, msg, bytes, true);
241}
242EXPORT_SYMBOL_GPL(sk_msg_free_partial);
243
244void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
245 u32 bytes)
246{
247 __sk_msg_free_partial(sk, msg, bytes, false);
248}
249
250void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
251{
252 int trim = msg->sg.size - len;
253 u32 i = msg->sg.end;
254
255 if (trim <= 0) {
256 WARN_ON(trim < 0);
257 return;
258 }
259
260 sk_msg_iter_var_prev(i);
261 msg->sg.size = len;
262 while (msg->sg.data[i].length &&
263 trim >= msg->sg.data[i].length) {
264 trim -= msg->sg.data[i].length;
265 sk_msg_free_elem(sk, msg, i, true);
266 sk_msg_iter_var_prev(i);
267 if (!trim)
268 goto out;
269 }
270
271 msg->sg.data[i].length -= trim;
272 sk_mem_uncharge(sk, trim);
273 /* Adjust copybreak if it falls into the trimmed part of last buf */
274 if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
275 msg->sg.copybreak = msg->sg.data[i].length;
276out:
277 sk_msg_iter_var_next(i);
278 msg->sg.end = i;
279
280 /* If we trim data a full sg elem before curr pointer update
281 * copybreak and current so that any future copy operations
282 * start at new copy location.
283 * However trimed data that has not yet been used in a copy op
284 * does not require an update.
285 */
286 if (!msg->sg.size) {
287 msg->sg.curr = msg->sg.start;
288 msg->sg.copybreak = 0;
289 } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
290 sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
291 sk_msg_iter_var_prev(i);
292 msg->sg.curr = i;
293 msg->sg.copybreak = msg->sg.data[i].length;
294 }
295}
296EXPORT_SYMBOL_GPL(sk_msg_trim);
297
298int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
299 struct sk_msg *msg, u32 bytes)
300{
301 int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
302 const int to_max_pages = MAX_MSG_FRAGS;
303 struct page *pages[MAX_MSG_FRAGS];
304 ssize_t orig, copied, use, offset;
305
306 orig = msg->sg.size;
307 while (bytes > 0) {
308 i = 0;
309 maxpages = to_max_pages - num_elems;
310 if (maxpages == 0) {
311 ret = -EFAULT;
312 goto out;
313 }
314
315 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
316 &offset);
317 if (copied <= 0) {
318 ret = -EFAULT;
319 goto out;
320 }
321
322 iov_iter_advance(from, copied);
323 bytes -= copied;
324 msg->sg.size += copied;
325
326 while (copied) {
327 use = min_t(int, copied, PAGE_SIZE - offset);
328 sg_set_page(&msg->sg.data[msg->sg.end],
329 pages[i], use, offset);
330 sg_unmark_end(&msg->sg.data[msg->sg.end]);
331 sk_mem_charge(sk, use);
332
333 offset = 0;
334 copied -= use;
335 sk_msg_iter_next(msg, end);
336 num_elems++;
337 i++;
338 }
339 /* When zerocopy is mixed with sk_msg_*copy* operations we
340 * may have a copybreak set in this case clear and prefer
341 * zerocopy remainder when possible.
342 */
343 msg->sg.copybreak = 0;
344 msg->sg.curr = msg->sg.end;
345 }
346out:
347 /* Revert iov_iter updates, msg will need to use 'trim' later if it
348 * also needs to be cleared.
349 */
350 if (ret)
351 iov_iter_revert(from, msg->sg.size - orig);
352 return ret;
353}
354EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
355
356int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
357 struct sk_msg *msg, u32 bytes)
358{
359 int ret = -ENOSPC, i = msg->sg.curr;
360 struct scatterlist *sge;
361 u32 copy, buf_size;
362 void *to;
363
364 do {
365 sge = sk_msg_elem(msg, i);
366 /* This is possible if a trim operation shrunk the buffer */
367 if (msg->sg.copybreak >= sge->length) {
368 msg->sg.copybreak = 0;
369 sk_msg_iter_var_next(i);
370 if (i == msg->sg.end)
371 break;
372 sge = sk_msg_elem(msg, i);
373 }
374
375 buf_size = sge->length - msg->sg.copybreak;
376 copy = (buf_size > bytes) ? bytes : buf_size;
377 to = sg_virt(sge) + msg->sg.copybreak;
378 msg->sg.copybreak += copy;
379 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
380 ret = copy_from_iter_nocache(to, copy, from);
381 else
382 ret = copy_from_iter(to, copy, from);
383 if (ret != copy) {
384 ret = -EFAULT;
385 goto out;
386 }
387 bytes -= copy;
388 if (!bytes)
389 break;
390 msg->sg.copybreak = 0;
391 sk_msg_iter_var_next(i);
392 } while (i != msg->sg.end);
393out:
394 msg->sg.curr = i;
395 return ret;
396}
397EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
398
399static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
400{
401 struct sock *sk = psock->sk;
402 int copied = 0, num_sge;
403 struct sk_msg *msg;
404
405 msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
406 if (unlikely(!msg))
407 return -EAGAIN;
408 if (!sk_rmem_schedule(sk, skb, skb->len)) {
409 kfree(msg);
410 return -EAGAIN;
411 }
412
413 sk_msg_init(msg);
414 num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
415 if (unlikely(num_sge < 0)) {
416 kfree(msg);
417 return num_sge;
418 }
419
420 sk_mem_charge(sk, skb->len);
421 copied = skb->len;
422 msg->sg.start = 0;
423 msg->sg.size = copied;
424 msg->sg.end = num_sge == MAX_MSG_FRAGS ? 0 : num_sge;
425 msg->skb = skb;
426
427 sk_psock_queue_msg(psock, msg);
428 sk_psock_data_ready(sk, psock);
429 return copied;
430}
431
432static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
433 u32 off, u32 len, bool ingress)
434{
435 if (ingress)
436 return sk_psock_skb_ingress(psock, skb);
437 else
438 return skb_send_sock_locked(psock->sk, skb, off, len);
439}
440
441static void sk_psock_backlog(struct work_struct *work)
442{
443 struct sk_psock *psock = container_of(work, struct sk_psock, work);
444 struct sk_psock_work_state *state = &psock->work_state;
445 struct sk_buff *skb;
446 bool ingress;
447 u32 len, off;
448 int ret;
449
450 /* Lock sock to avoid losing sk_socket during loop. */
451 lock_sock(psock->sk);
452 if (state->skb) {
453 skb = state->skb;
454 len = state->len;
455 off = state->off;
456 state->skb = NULL;
457 goto start;
458 }
459
460 while ((skb = skb_dequeue(&psock->ingress_skb))) {
461 len = skb->len;
462 off = 0;
463start:
464 ingress = tcp_skb_bpf_ingress(skb);
465 do {
466 ret = -EIO;
467 if (likely(psock->sk->sk_socket))
468 ret = sk_psock_handle_skb(psock, skb, off,
469 len, ingress);
470 if (ret <= 0) {
471 if (ret == -EAGAIN) {
472 state->skb = skb;
473 state->len = len;
474 state->off = off;
475 goto end;
476 }
477 /* Hard errors break pipe and stop xmit. */
478 sk_psock_report_error(psock, ret ? -ret : EPIPE);
479 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
480 kfree_skb(skb);
481 goto end;
482 }
483 off += ret;
484 len -= ret;
485 } while (len);
486
487 if (!ingress)
488 kfree_skb(skb);
489 }
490end:
491 release_sock(psock->sk);
492}
493
494struct sk_psock *sk_psock_init(struct sock *sk, int node)
495{
496 struct sk_psock *psock = kzalloc_node(sizeof(*psock),
497 GFP_ATOMIC | __GFP_NOWARN,
498 node);
499 if (!psock)
500 return NULL;
501
502 psock->sk = sk;
503 psock->eval = __SK_NONE;
504
505 INIT_LIST_HEAD(&psock->link);
506 spin_lock_init(&psock->link_lock);
507
508 INIT_WORK(&psock->work, sk_psock_backlog);
509 INIT_LIST_HEAD(&psock->ingress_msg);
510 skb_queue_head_init(&psock->ingress_skb);
511
512 sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
513 refcount_set(&psock->refcnt, 1);
514
515 rcu_assign_sk_user_data(sk, psock);
516 sock_hold(sk);
517
518 return psock;
519}
520EXPORT_SYMBOL_GPL(sk_psock_init);
521
522struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
523{
524 struct sk_psock_link *link;
525
526 spin_lock_bh(&psock->link_lock);
527 link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
528 list);
529 if (link)
530 list_del(&link->list);
531 spin_unlock_bh(&psock->link_lock);
532 return link;
533}
534
535void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
536{
537 struct sk_msg *msg, *tmp;
538
539 list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
540 list_del(&msg->list);
541 sk_msg_free(psock->sk, msg);
542 kfree(msg);
543 }
544}
545
546static void sk_psock_zap_ingress(struct sk_psock *psock)
547{
548 __skb_queue_purge(&psock->ingress_skb);
549 __sk_psock_purge_ingress_msg(psock);
550}
551
552static void sk_psock_link_destroy(struct sk_psock *psock)
553{
554 struct sk_psock_link *link, *tmp;
555
556 list_for_each_entry_safe(link, tmp, &psock->link, list) {
557 list_del(&link->list);
558 sk_psock_free_link(link);
559 }
560}
561
562static void sk_psock_destroy_deferred(struct work_struct *gc)
563{
564 struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
565
566 /* No sk_callback_lock since already detached. */
567
568 /* Parser has been stopped */
569 if (psock->progs.skb_parser)
570 strp_done(&psock->parser.strp);
571
572 cancel_work_sync(&psock->work);
573
574 psock_progs_drop(&psock->progs);
575
576 sk_psock_link_destroy(psock);
577 sk_psock_cork_free(psock);
578 sk_psock_zap_ingress(psock);
579
580 if (psock->sk_redir)
581 sock_put(psock->sk_redir);
582 sock_put(psock->sk);
583 kfree(psock);
584}
585
586void sk_psock_destroy(struct rcu_head *rcu)
587{
588 struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
589
590 INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
591 schedule_work(&psock->gc);
592}
593EXPORT_SYMBOL_GPL(sk_psock_destroy);
594
595void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
596{
597 sk_psock_cork_free(psock);
598 sk_psock_zap_ingress(psock);
599
600 write_lock_bh(&sk->sk_callback_lock);
601 sk_psock_restore_proto(sk, psock);
602 rcu_assign_sk_user_data(sk, NULL);
603 if (psock->progs.skb_parser)
604 sk_psock_stop_strp(sk, psock);
605 write_unlock_bh(&sk->sk_callback_lock);
606 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
607
608 call_rcu(&psock->rcu, sk_psock_destroy);
609}
610EXPORT_SYMBOL_GPL(sk_psock_drop);
611
612static int sk_psock_map_verd(int verdict, bool redir)
613{
614 switch (verdict) {
615 case SK_PASS:
616 return redir ? __SK_REDIRECT : __SK_PASS;
617 case SK_DROP:
618 default:
619 break;
620 }
621
622 return __SK_DROP;
623}
624
625int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
626 struct sk_msg *msg)
627{
628 struct bpf_prog *prog;
629 int ret;
630
631 preempt_disable();
632 rcu_read_lock();
633 prog = READ_ONCE(psock->progs.msg_parser);
634 if (unlikely(!prog)) {
635 ret = __SK_PASS;
636 goto out;
637 }
638
639 sk_msg_compute_data_pointers(msg);
640 msg->sk = sk;
641 ret = BPF_PROG_RUN(prog, msg);
642 ret = sk_psock_map_verd(ret, msg->sk_redir);
643 psock->apply_bytes = msg->apply_bytes;
644 if (ret == __SK_REDIRECT) {
645 if (psock->sk_redir)
646 sock_put(psock->sk_redir);
647 psock->sk_redir = msg->sk_redir;
648 if (!psock->sk_redir) {
649 ret = __SK_DROP;
650 goto out;
651 }
652 sock_hold(psock->sk_redir);
653 }
654out:
655 rcu_read_unlock();
656 preempt_enable();
657 return ret;
658}
659EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
660
661static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
662 struct sk_buff *skb)
663{
664 int ret;
665
666 skb->sk = psock->sk;
667 bpf_compute_data_end_sk_skb(skb);
668 preempt_disable();
669 ret = BPF_PROG_RUN(prog, skb);
670 preempt_enable();
671 /* strparser clones the skb before handing it to a upper layer,
672 * meaning skb_orphan has been called. We NULL sk on the way out
673 * to ensure we don't trigger a BUG_ON() in skb/sk operations
674 * later and because we are not charging the memory of this skb
675 * to any socket yet.
676 */
677 skb->sk = NULL;
678 return ret;
679}
680
681static struct sk_psock *sk_psock_from_strp(struct strparser *strp)
682{
683 struct sk_psock_parser *parser;
684
685 parser = container_of(strp, struct sk_psock_parser, strp);
686 return container_of(parser, struct sk_psock, parser);
687}
688
689static void sk_psock_verdict_apply(struct sk_psock *psock,
690 struct sk_buff *skb, int verdict)
691{
692 struct sk_psock *psock_other;
693 struct sock *sk_other;
694 bool ingress;
695
696 switch (verdict) {
697 case __SK_PASS:
698 sk_other = psock->sk;
699 if (sock_flag(sk_other, SOCK_DEAD) ||
700 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
701 goto out_free;
702 }
703 if (atomic_read(&sk_other->sk_rmem_alloc) <=
704 sk_other->sk_rcvbuf) {
705 struct tcp_skb_cb *tcp = TCP_SKB_CB(skb);
706
707 tcp->bpf.flags |= BPF_F_INGRESS;
708 skb_queue_tail(&psock->ingress_skb, skb);
709 schedule_work(&psock->work);
710 break;
711 }
712 goto out_free;
713 case __SK_REDIRECT:
714 sk_other = tcp_skb_bpf_redirect_fetch(skb);
715 if (unlikely(!sk_other))
716 goto out_free;
717 psock_other = sk_psock(sk_other);
718 if (!psock_other || sock_flag(sk_other, SOCK_DEAD) ||
719 !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED))
720 goto out_free;
721 ingress = tcp_skb_bpf_ingress(skb);
722 if ((!ingress && sock_writeable(sk_other)) ||
723 (ingress &&
724 atomic_read(&sk_other->sk_rmem_alloc) <=
725 sk_other->sk_rcvbuf)) {
726 if (!ingress)
727 skb_set_owner_w(skb, sk_other);
728 skb_queue_tail(&psock_other->ingress_skb, skb);
729 schedule_work(&psock_other->work);
730 break;
731 }
732 /* fall-through */
733 case __SK_DROP:
734 /* fall-through */
735 default:
736out_free:
737 kfree_skb(skb);
738 }
739}
740
741static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
742{
743 struct sk_psock *psock = sk_psock_from_strp(strp);
744 struct bpf_prog *prog;
745 int ret = __SK_DROP;
746
747 rcu_read_lock();
748 prog = READ_ONCE(psock->progs.skb_verdict);
749 if (likely(prog)) {
750 skb_orphan(skb);
751 tcp_skb_bpf_redirect_clear(skb);
752 ret = sk_psock_bpf_run(psock, prog, skb);
753 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
754 }
755 rcu_read_unlock();
756 sk_psock_verdict_apply(psock, skb, ret);
757}
758
759static int sk_psock_strp_read_done(struct strparser *strp, int err)
760{
761 return err;
762}
763
764static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
765{
766 struct sk_psock *psock = sk_psock_from_strp(strp);
767 struct bpf_prog *prog;
768 int ret = skb->len;
769
770 rcu_read_lock();
771 prog = READ_ONCE(psock->progs.skb_parser);
772 if (likely(prog))
773 ret = sk_psock_bpf_run(psock, prog, skb);
774 rcu_read_unlock();
775 return ret;
776}
777
778/* Called with socket lock held. */
779static void sk_psock_strp_data_ready(struct sock *sk)
780{
781 struct sk_psock *psock;
782
783 rcu_read_lock();
784 psock = sk_psock(sk);
785 if (likely(psock)) {
786 write_lock_bh(&sk->sk_callback_lock);
787 strp_data_ready(&psock->parser.strp);
788 write_unlock_bh(&sk->sk_callback_lock);
789 }
790 rcu_read_unlock();
791}
792
793static void sk_psock_write_space(struct sock *sk)
794{
795 struct sk_psock *psock;
796 void (*write_space)(struct sock *sk);
797
798 rcu_read_lock();
799 psock = sk_psock(sk);
800 if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)))
801 schedule_work(&psock->work);
802 write_space = psock->saved_write_space;
803 rcu_read_unlock();
804 write_space(sk);
805}
806
807int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
808{
809 static const struct strp_callbacks cb = {
810 .rcv_msg = sk_psock_strp_read,
811 .read_sock_done = sk_psock_strp_read_done,
812 .parse_msg = sk_psock_strp_parse,
813 };
814
815 psock->parser.enabled = false;
816 return strp_init(&psock->parser.strp, sk, &cb);
817}
818
819void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
820{
821 struct sk_psock_parser *parser = &psock->parser;
822
823 if (parser->enabled)
824 return;
825
826 parser->saved_data_ready = sk->sk_data_ready;
827 sk->sk_data_ready = sk_psock_strp_data_ready;
828 sk->sk_write_space = sk_psock_write_space;
829 parser->enabled = true;
830}
831
832void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
833{
834 struct sk_psock_parser *parser = &psock->parser;
835
836 if (!parser->enabled)
837 return;
838
839 sk->sk_data_ready = parser->saved_data_ready;
840 parser->saved_data_ready = NULL;
841 strp_stop(&parser->strp);
842 parser->enabled = false;
843}