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, size: 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(sg: 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(sg: sge);
68 sg_set_page(sg: sge, page: pfrag->page, len: use, offset: orig_offset);
69 get_page(page: pfrag->page);
70 sk_msg_iter_next(msg, end);
71 }
72
73 sk_mem_charge(sk, size: 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, len: 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(msg: src, which: 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(msg: src, which: 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(msg: dst, which: dst->sg.end - 1);
112
113 if (sgd &&
114 (sg_page(sg: sge) == sg_page(sg: sgd)) &&
115 (sg_virt(sg: sge) + off == sg_virt(sg: sgd) + sgd->length)) {
116 sgd->length += sge_len;
117 dst->sg.size += sge_len;
118 } else if (!sk_msg_full(msg: dst)) {
119 sge_off = sge->offset + off;
120 sk_msg_page_add(msg: dst, page: sg_page(sg: sge), len: sge_len, offset: sge_off);
121 } else {
122 return -ENOSPC;
123 }
124
125 off = 0;
126 len -= sge_len;
127 sk_mem_charge(sk, size: sge_len);
128 sk_msg_iter_var_next(i);
129 if (i == src->sg.end && len)
130 return -ENOSPC;
131 sge = sk_msg_elem(msg: src, which: 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, which: i);
144
145 if (bytes < sge->length) {
146 sge->length -= bytes;
147 sge->offset += bytes;
148 sk_mem_uncharge(sk, size: bytes);
149 break;
150 }
151
152 sk_mem_uncharge(sk, size: 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, size: 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, which: 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, size: len);
187 put_page(page: sg_page(sg: 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, which: 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, bytes: msg->sg.size);
204 sge = sk_msg_elem(msg, which: i);
205 }
206 consume_skb(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, i: msg->sg.start, charge: 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, i: msg->sg.start, charge: 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, which: i);
231 if (!sge->length)
232 break;
233 if (bytes < sge->length) {
234 if (charge)
235 sk_mem_uncharge(sk, size: 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, charge: 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, charge: 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, charge: 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, size: 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(start: msg->sg.start, end: msg->sg.curr) >=
303 sk_msg_iter_dist(start: msg->sg.start, end: 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(i: from, pages, maxsize: bytes, maxpages,
329 start: &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(sg: &msg->sg.data[msg->sg.end],
341 page: pages[i], len: use, offset);
342 sg_unmark_end(sg: &msg->sg.data[msg->sg.end]);
343 sk_mem_charge(sk, size: 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(i: from, bytes: 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, which: 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, which: i);
385 }
386
387 buf_size = sge->length - msg->sg.copybreak;
388 copy = (buf_size > bytes) ? bytes : buf_size;
389 to = sg_virt(sg: 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(addr: to, bytes: copy, i: from);
393 else
394 ret = copy_from_iter(addr: to, bytes: copy, i: 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: msg_rx, which: i);
433 copy = sge->length;
434 page = sg_page(sg: sge);
435 if (copied + copy > len)
436 copy = len - copied;
437 copy = copy_page_to_iter(page, offset: sge->offset, bytes: copy, i: 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, size: 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(sg: sge));
468
469 if (unlikely(peek)) {
470 msg_rx = sk_psock_next_msg(psock, msg: 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(sg: sge))) {
478 msg_rx = sk_psock_dequeue_msg(psock);
479 kfree_sk_msg(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(head: &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(size: sizeof(*msg), flags: gfp | __GFP_NOWARN);
507 if (unlikely(!msg))
508 return NULL;
509 sg_init_marker(sgl: 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(v: &sk->sk_rmem_alloc) > sk->sk_rcvbuf)
517 return NULL;
518
519 if (!sk_rmem_schedule(sk, skb, size: 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, sg: msg->sg.data, offset: 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, sg: msg->sg.data, offset: 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(objp: 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(objp: 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(sk: psock->sk))
619 return -EAGAIN;
620 return skb_send_sock(sk: psock->sk, skb, offset: 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(lock: &psock->ingress_lock);
634 if (sk_psock_test_state(psock, bit: SK_PSOCK_TX_ENABLED)) {
635 state->len = len;
636 state->off = off;
637 }
638 spin_unlock_bh(lock: &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(list_: &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(sk: psock->sk, flag: 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, bit: SK_PSOCK_TX_ENABLED))
681 schedule_delayed_work(dwork: &psock->work, delay: 1);
682 goto end;
683 }
684 /* Hard errors break pipe and stop xmit. */
685 sk_psock_report_error(psock, err: ret ? -ret : EPIPE);
686 sk_psock_clear_state(psock, bit: SK_PSOCK_TX_ENABLED);
687 goto end;
688 }
689 off += ret;
690 len -= ret;
691 } while (len);
692
693 skb = skb_dequeue(list: &psock->ingress_skb);
694 kfree_skb(skb);
695 }
696end:
697 mutex_unlock(lock: &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(error: -EINVAL);
709 goto out;
710 }
711
712 if (sk->sk_user_data) {
713 psock = ERR_PTR(error: -EBUSY);
714 goto out;
715 }
716
717 psock = kzalloc_node(size: sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
718 if (!psock) {
719 psock = ERR_PTR(error: -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(list: &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(list: &psock->ingress_msg);
738 spin_lock_init(&psock->ingress_lock);
739 skb_queue_head_init(list: &psock->ingress_skb);
740
741 sk_psock_set_state(psock, bit: SK_PSOCK_TX_ENABLED);
742 refcount_set(r: &psock->refcnt, n: 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(lock: &psock->link_lock);
760 link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
761 list);
762 if (link)
763 list_del(entry: &link->list);
764 spin_unlock_bh(lock: &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(entry: &msg->list);
774 sk_msg_free(psock->sk, msg);
775 kfree(objp: 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(list: &psock->ingress_skb)) != NULL) {
784 skb_bpf_redirect_clear(skb);
785 sock_drop(sk: 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(entry: &link->list);
796 sk_psock_free_link(link);
797 }
798}
799
800void sk_psock_stop(struct sk_psock *psock)
801{
802 spin_lock_bh(lock: &psock->ingress_lock);
803 sk_psock_clear_state(psock, bit: SK_PSOCK_TX_ENABLED);
804 sk_psock_cork_free(psock);
805 spin_unlock_bh(lock: &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(dwork: &psock->work);
819 __sk_psock_zap_ingress(psock);
820 mutex_destroy(lock: &psock->work_mutex);
821
822 psock_progs_drop(progs: &psock->progs);
823
824 sk_psock_link_destroy(psock);
825 sk_psock_cork_free(psock);
826
827 if (psock->sk_redir)
828 sock_put(sk: psock->sk_redir);
829 sock_put(sk: psock->sk);
830 kfree(objp: psock);
831}
832
833void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
834{
835 write_lock_bh(&sk->sk_callback_lock);
836 sk_psock_restore_proto(sk, psock);
837 rcu_assign_sk_user_data(sk, NULL);
838 if (psock->progs.stream_parser)
839 sk_psock_stop_strp(sk, psock);
840 else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
841 sk_psock_stop_verdict(sk, psock);
842 write_unlock_bh(&sk->sk_callback_lock);
843
844 sk_psock_stop(psock);
845
846 INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
847 queue_rcu_work(wq: system_wq, rwork: &psock->rwork);
848}
849EXPORT_SYMBOL_GPL(sk_psock_drop);
850
851static int sk_psock_map_verd(int verdict, bool redir)
852{
853 switch (verdict) {
854 case SK_PASS:
855 return redir ? __SK_REDIRECT : __SK_PASS;
856 case SK_DROP:
857 default:
858 break;
859 }
860
861 return __SK_DROP;
862}
863
864int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
865 struct sk_msg *msg)
866{
867 struct bpf_prog *prog;
868 int ret;
869
870 rcu_read_lock();
871 prog = READ_ONCE(psock->progs.msg_parser);
872 if (unlikely(!prog)) {
873 ret = __SK_PASS;
874 goto out;
875 }
876
877 sk_msg_compute_data_pointers(msg);
878 msg->sk = sk;
879 ret = bpf_prog_run_pin_on_cpu(prog, ctx: msg);
880 ret = sk_psock_map_verd(verdict: ret, redir: msg->sk_redir);
881 psock->apply_bytes = msg->apply_bytes;
882 if (ret == __SK_REDIRECT) {
883 if (psock->sk_redir) {
884 sock_put(sk: psock->sk_redir);
885 psock->sk_redir = NULL;
886 }
887 if (!msg->sk_redir) {
888 ret = __SK_DROP;
889 goto out;
890 }
891 psock->redir_ingress = sk_msg_to_ingress(msg);
892 psock->sk_redir = msg->sk_redir;
893 sock_hold(sk: psock->sk_redir);
894 }
895out:
896 rcu_read_unlock();
897 return ret;
898}
899EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
900
901static int sk_psock_skb_redirect(struct sk_psock *from, struct sk_buff *skb)
902{
903 struct sk_psock *psock_other;
904 struct sock *sk_other;
905
906 sk_other = skb_bpf_redirect_fetch(skb);
907 /* This error is a buggy BPF program, it returned a redirect
908 * return code, but then didn't set a redirect interface.
909 */
910 if (unlikely(!sk_other)) {
911 skb_bpf_redirect_clear(skb);
912 sock_drop(sk: from->sk, skb);
913 return -EIO;
914 }
915 psock_other = sk_psock(sk: sk_other);
916 /* This error indicates the socket is being torn down or had another
917 * error that caused the pipe to break. We can't send a packet on
918 * a socket that is in this state so we drop the skb.
919 */
920 if (!psock_other || sock_flag(sk: sk_other, flag: SOCK_DEAD)) {
921 skb_bpf_redirect_clear(skb);
922 sock_drop(sk: from->sk, skb);
923 return -EIO;
924 }
925 spin_lock_bh(lock: &psock_other->ingress_lock);
926 if (!sk_psock_test_state(psock: psock_other, bit: SK_PSOCK_TX_ENABLED)) {
927 spin_unlock_bh(lock: &psock_other->ingress_lock);
928 skb_bpf_redirect_clear(skb);
929 sock_drop(sk: from->sk, skb);
930 return -EIO;
931 }
932
933 skb_queue_tail(list: &psock_other->ingress_skb, newsk: skb);
934 schedule_delayed_work(dwork: &psock_other->work, delay: 0);
935 spin_unlock_bh(lock: &psock_other->ingress_lock);
936 return 0;
937}
938
939static void sk_psock_tls_verdict_apply(struct sk_buff *skb,
940 struct sk_psock *from, int verdict)
941{
942 switch (verdict) {
943 case __SK_REDIRECT:
944 sk_psock_skb_redirect(from, skb);
945 break;
946 case __SK_PASS:
947 case __SK_DROP:
948 default:
949 break;
950 }
951}
952
953int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
954{
955 struct bpf_prog *prog;
956 int ret = __SK_PASS;
957
958 rcu_read_lock();
959 prog = READ_ONCE(psock->progs.stream_verdict);
960 if (likely(prog)) {
961 skb->sk = psock->sk;
962 skb_dst_drop(skb);
963 skb_bpf_redirect_clear(skb);
964 ret = bpf_prog_run_pin_on_cpu(prog, ctx: skb);
965 ret = sk_psock_map_verd(verdict: ret, redir: skb_bpf_redirect_fetch(skb));
966 skb->sk = NULL;
967 }
968 sk_psock_tls_verdict_apply(skb, from: psock, verdict: ret);
969 rcu_read_unlock();
970 return ret;
971}
972EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
973
974static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
975 int verdict)
976{
977 struct sock *sk_other;
978 int err = 0;
979 u32 len, off;
980
981 switch (verdict) {
982 case __SK_PASS:
983 err = -EIO;
984 sk_other = psock->sk;
985 if (sock_flag(sk: sk_other, flag: SOCK_DEAD) ||
986 !sk_psock_test_state(psock, bit: SK_PSOCK_TX_ENABLED))
987 goto out_free;
988
989 skb_bpf_set_ingress(skb);
990
991 /* If the queue is empty then we can submit directly
992 * into the msg queue. If its not empty we have to
993 * queue work otherwise we may get OOO data. Otherwise,
994 * if sk_psock_skb_ingress errors will be handled by
995 * retrying later from workqueue.
996 */
997 if (skb_queue_empty(list: &psock->ingress_skb)) {
998 len = skb->len;
999 off = 0;
1000 if (skb_bpf_strparser(skb)) {
1001 struct strp_msg *stm = strp_msg(skb);
1002
1003 off = stm->offset;
1004 len = stm->full_len;
1005 }
1006 err = sk_psock_skb_ingress_self(psock, skb, off, len);
1007 }
1008 if (err < 0) {
1009 spin_lock_bh(lock: &psock->ingress_lock);
1010 if (sk_psock_test_state(psock, bit: SK_PSOCK_TX_ENABLED)) {
1011 skb_queue_tail(list: &psock->ingress_skb, newsk: skb);
1012 schedule_delayed_work(dwork: &psock->work, delay: 0);
1013 err = 0;
1014 }
1015 spin_unlock_bh(lock: &psock->ingress_lock);
1016 if (err < 0)
1017 goto out_free;
1018 }
1019 break;
1020 case __SK_REDIRECT:
1021 tcp_eat_skb(sk: psock->sk, skb);
1022 err = sk_psock_skb_redirect(from: psock, skb);
1023 break;
1024 case __SK_DROP:
1025 default:
1026out_free:
1027 skb_bpf_redirect_clear(skb);
1028 tcp_eat_skb(sk: psock->sk, skb);
1029 sock_drop(sk: psock->sk, skb);
1030 }
1031
1032 return err;
1033}
1034
1035static void sk_psock_write_space(struct sock *sk)
1036{
1037 struct sk_psock *psock;
1038 void (*write_space)(struct sock *sk) = NULL;
1039
1040 rcu_read_lock();
1041 psock = sk_psock(sk);
1042 if (likely(psock)) {
1043 if (sk_psock_test_state(psock, bit: SK_PSOCK_TX_ENABLED))
1044 schedule_delayed_work(dwork: &psock->work, delay: 0);
1045 write_space = psock->saved_write_space;
1046 }
1047 rcu_read_unlock();
1048 if (write_space)
1049 write_space(sk);
1050}
1051
1052#if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1053static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
1054{
1055 struct sk_psock *psock;
1056 struct bpf_prog *prog;
1057 int ret = __SK_DROP;
1058 struct sock *sk;
1059
1060 rcu_read_lock();
1061 sk = strp->sk;
1062 psock = sk_psock(sk);
1063 if (unlikely(!psock)) {
1064 sock_drop(sk, skb);
1065 goto out;
1066 }
1067 prog = READ_ONCE(psock->progs.stream_verdict);
1068 if (likely(prog)) {
1069 skb->sk = sk;
1070 skb_dst_drop(skb);
1071 skb_bpf_redirect_clear(skb);
1072 ret = bpf_prog_run_pin_on_cpu(prog, ctx: skb);
1073 skb_bpf_set_strparser(skb);
1074 ret = sk_psock_map_verd(verdict: ret, redir: skb_bpf_redirect_fetch(skb));
1075 skb->sk = NULL;
1076 }
1077 sk_psock_verdict_apply(psock, skb, verdict: ret);
1078out:
1079 rcu_read_unlock();
1080}
1081
1082static int sk_psock_strp_read_done(struct strparser *strp, int err)
1083{
1084 return err;
1085}
1086
1087static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
1088{
1089 struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1090 struct bpf_prog *prog;
1091 int ret = skb->len;
1092
1093 rcu_read_lock();
1094 prog = READ_ONCE(psock->progs.stream_parser);
1095 if (likely(prog)) {
1096 skb->sk = psock->sk;
1097 ret = bpf_prog_run_pin_on_cpu(prog, ctx: skb);
1098 skb->sk = NULL;
1099 }
1100 rcu_read_unlock();
1101 return ret;
1102}
1103
1104/* Called with socket lock held. */
1105static void sk_psock_strp_data_ready(struct sock *sk)
1106{
1107 struct sk_psock *psock;
1108
1109 trace_sk_data_ready(sk);
1110
1111 rcu_read_lock();
1112 psock = sk_psock(sk);
1113 if (likely(psock)) {
1114 if (tls_sw_has_ctx_rx(sk)) {
1115 psock->saved_data_ready(sk);
1116 } else {
1117 write_lock_bh(&sk->sk_callback_lock);
1118 strp_data_ready(strp: &psock->strp);
1119 write_unlock_bh(&sk->sk_callback_lock);
1120 }
1121 }
1122 rcu_read_unlock();
1123}
1124
1125int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
1126{
1127 int ret;
1128
1129 static const struct strp_callbacks cb = {
1130 .rcv_msg = sk_psock_strp_read,
1131 .read_sock_done = sk_psock_strp_read_done,
1132 .parse_msg = sk_psock_strp_parse,
1133 };
1134
1135 ret = strp_init(strp: &psock->strp, sk, cb: &cb);
1136 if (!ret)
1137 sk_psock_set_state(psock, bit: SK_PSOCK_RX_STRP_ENABLED);
1138
1139 return ret;
1140}
1141
1142void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
1143{
1144 if (psock->saved_data_ready)
1145 return;
1146
1147 psock->saved_data_ready = sk->sk_data_ready;
1148 sk->sk_data_ready = sk_psock_strp_data_ready;
1149 sk->sk_write_space = sk_psock_write_space;
1150}
1151
1152void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
1153{
1154 psock_set_prog(pprog: &psock->progs.stream_parser, NULL);
1155
1156 if (!psock->saved_data_ready)
1157 return;
1158
1159 sk->sk_data_ready = psock->saved_data_ready;
1160 psock->saved_data_ready = NULL;
1161 strp_stop(strp: &psock->strp);
1162}
1163
1164static void sk_psock_done_strp(struct sk_psock *psock)
1165{
1166 /* Parser has been stopped */
1167 if (sk_psock_test_state(psock, bit: SK_PSOCK_RX_STRP_ENABLED))
1168 strp_done(strp: &psock->strp);
1169}
1170#else
1171static void sk_psock_done_strp(struct sk_psock *psock)
1172{
1173}
1174#endif /* CONFIG_BPF_STREAM_PARSER */
1175
1176static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
1177{
1178 struct sk_psock *psock;
1179 struct bpf_prog *prog;
1180 int ret = __SK_DROP;
1181 int len = skb->len;
1182
1183 rcu_read_lock();
1184 psock = sk_psock(sk);
1185 if (unlikely(!psock)) {
1186 len = 0;
1187 tcp_eat_skb(sk, skb);
1188 sock_drop(sk, skb);
1189 goto out;
1190 }
1191 prog = READ_ONCE(psock->progs.stream_verdict);
1192 if (!prog)
1193 prog = READ_ONCE(psock->progs.skb_verdict);
1194 if (likely(prog)) {
1195 skb_dst_drop(skb);
1196 skb_bpf_redirect_clear(skb);
1197 ret = bpf_prog_run_pin_on_cpu(prog, ctx: skb);
1198 ret = sk_psock_map_verd(verdict: ret, redir: skb_bpf_redirect_fetch(skb));
1199 }
1200 ret = sk_psock_verdict_apply(psock, skb, verdict: ret);
1201 if (ret < 0)
1202 len = ret;
1203out:
1204 rcu_read_unlock();
1205 return len;
1206}
1207
1208static void sk_psock_verdict_data_ready(struct sock *sk)
1209{
1210 struct socket *sock = sk->sk_socket;
1211 const struct proto_ops *ops;
1212 int copied;
1213
1214 trace_sk_data_ready(sk);
1215
1216 if (unlikely(!sock))
1217 return;
1218 ops = READ_ONCE(sock->ops);
1219 if (!ops || !ops->read_skb)
1220 return;
1221 copied = ops->read_skb(sk, sk_psock_verdict_recv);
1222 if (copied >= 0) {
1223 struct sk_psock *psock;
1224
1225 rcu_read_lock();
1226 psock = sk_psock(sk);
1227 if (psock)
1228 psock->saved_data_ready(sk);
1229 rcu_read_unlock();
1230 }
1231}
1232
1233void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1234{
1235 if (psock->saved_data_ready)
1236 return;
1237
1238 psock->saved_data_ready = sk->sk_data_ready;
1239 sk->sk_data_ready = sk_psock_verdict_data_ready;
1240 sk->sk_write_space = sk_psock_write_space;
1241}
1242
1243void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1244{
1245 psock_set_prog(pprog: &psock->progs.stream_verdict, NULL);
1246 psock_set_prog(pprog: &psock->progs.skb_verdict, NULL);
1247
1248 if (!psock->saved_data_ready)
1249 return;
1250
1251 sk->sk_data_ready = psock->saved_data_ready;
1252 psock->saved_data_ready = NULL;
1253}
1254

source code of linux/net/core/skmsg.c