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
sk_msg_try_coalesce_ok(struct sk_msg * msg,int elem_first_coalesce)12 static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
13 {
14 if (msg->sg.end > msg->sg.start &&
15 elem_first_coalesce < msg->sg.end)
16 return true;
17
18 if (msg->sg.end < msg->sg.start &&
19 (elem_first_coalesce > msg->sg.start ||
20 elem_first_coalesce < msg->sg.end))
21 return true;
22
23 return false;
24 }
25
sk_msg_alloc(struct sock * sk,struct sk_msg * msg,int len,int elem_first_coalesce)26 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
27 int elem_first_coalesce)
28 {
29 struct page_frag *pfrag = sk_page_frag(sk);
30 u32 osize = msg->sg.size;
31 int ret = 0;
32
33 len -= msg->sg.size;
34 while (len > 0) {
35 struct scatterlist *sge;
36 u32 orig_offset;
37 int use, i;
38
39 if (!sk_page_frag_refill(sk, pfrag)) {
40 ret = -ENOMEM;
41 goto msg_trim;
42 }
43
44 orig_offset = pfrag->offset;
45 use = min_t(int, len, pfrag->size - orig_offset);
46 if (!sk_wmem_schedule(sk, use)) {
47 ret = -ENOMEM;
48 goto msg_trim;
49 }
50
51 i = msg->sg.end;
52 sk_msg_iter_var_prev(i);
53 sge = &msg->sg.data[i];
54
55 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
56 sg_page(sge) == pfrag->page &&
57 sge->offset + sge->length == orig_offset) {
58 sge->length += use;
59 } else {
60 if (sk_msg_full(msg)) {
61 ret = -ENOSPC;
62 break;
63 }
64
65 sge = &msg->sg.data[msg->sg.end];
66 sg_unmark_end(sge);
67 sg_set_page(sge, pfrag->page, use, orig_offset);
68 get_page(pfrag->page);
69 sk_msg_iter_next(msg, end);
70 }
71
72 sk_mem_charge(sk, use);
73 msg->sg.size += use;
74 pfrag->offset += use;
75 len -= use;
76 }
77
78 return ret;
79
80 msg_trim:
81 sk_msg_trim(sk, msg, osize);
82 return ret;
83 }
84 EXPORT_SYMBOL_GPL(sk_msg_alloc);
85
sk_msg_clone(struct sock * sk,struct sk_msg * dst,struct sk_msg * src,u32 off,u32 len)86 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
87 u32 off, u32 len)
88 {
89 int i = src->sg.start;
90 struct scatterlist *sge = sk_msg_elem(src, i);
91 struct scatterlist *sgd = NULL;
92 u32 sge_len, sge_off;
93
94 while (off) {
95 if (sge->length > off)
96 break;
97 off -= sge->length;
98 sk_msg_iter_var_next(i);
99 if (i == src->sg.end && off)
100 return -ENOSPC;
101 sge = sk_msg_elem(src, i);
102 }
103
104 while (len) {
105 sge_len = sge->length - off;
106 if (sge_len > len)
107 sge_len = len;
108
109 if (dst->sg.end)
110 sgd = sk_msg_elem(dst, dst->sg.end - 1);
111
112 if (sgd &&
113 (sg_page(sge) == sg_page(sgd)) &&
114 (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
115 sgd->length += sge_len;
116 dst->sg.size += sge_len;
117 } else if (!sk_msg_full(dst)) {
118 sge_off = sge->offset + off;
119 sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
120 } else {
121 return -ENOSPC;
122 }
123
124 off = 0;
125 len -= sge_len;
126 sk_mem_charge(sk, sge_len);
127 sk_msg_iter_var_next(i);
128 if (i == src->sg.end && len)
129 return -ENOSPC;
130 sge = sk_msg_elem(src, i);
131 }
132
133 return 0;
134 }
135 EXPORT_SYMBOL_GPL(sk_msg_clone);
136
sk_msg_return_zero(struct sock * sk,struct sk_msg * msg,int bytes)137 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
138 {
139 int i = msg->sg.start;
140
141 do {
142 struct scatterlist *sge = sk_msg_elem(msg, i);
143
144 if (bytes < sge->length) {
145 sge->length -= bytes;
146 sge->offset += bytes;
147 sk_mem_uncharge(sk, bytes);
148 break;
149 }
150
151 sk_mem_uncharge(sk, sge->length);
152 bytes -= sge->length;
153 sge->length = 0;
154 sge->offset = 0;
155 sk_msg_iter_var_next(i);
156 } while (bytes && i != msg->sg.end);
157 msg->sg.start = i;
158 }
159 EXPORT_SYMBOL_GPL(sk_msg_return_zero);
160
sk_msg_return(struct sock * sk,struct sk_msg * msg,int bytes)161 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
162 {
163 int i = msg->sg.start;
164
165 do {
166 struct scatterlist *sge = &msg->sg.data[i];
167 int uncharge = (bytes < sge->length) ? bytes : sge->length;
168
169 sk_mem_uncharge(sk, uncharge);
170 bytes -= uncharge;
171 sk_msg_iter_var_next(i);
172 } while (i != msg->sg.end);
173 }
174 EXPORT_SYMBOL_GPL(sk_msg_return);
175
sk_msg_free_elem(struct sock * sk,struct sk_msg * msg,u32 i,bool charge)176 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
177 bool charge)
178 {
179 struct scatterlist *sge = sk_msg_elem(msg, i);
180 u32 len = sge->length;
181
182 /* When the skb owns the memory we free it from consume_skb path. */
183 if (!msg->skb) {
184 if (charge)
185 sk_mem_uncharge(sk, len);
186 put_page(sg_page(sge));
187 }
188 memset(sge, 0, sizeof(*sge));
189 return len;
190 }
191
__sk_msg_free(struct sock * sk,struct sk_msg * msg,u32 i,bool charge)192 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
193 bool charge)
194 {
195 struct scatterlist *sge = sk_msg_elem(msg, i);
196 int freed = 0;
197
198 while (msg->sg.size) {
199 msg->sg.size -= sge->length;
200 freed += sk_msg_free_elem(sk, msg, i, charge);
201 sk_msg_iter_var_next(i);
202 sk_msg_check_to_free(msg, i, msg->sg.size);
203 sge = sk_msg_elem(msg, i);
204 }
205 consume_skb(msg->skb);
206 sk_msg_init(msg);
207 return freed;
208 }
209
sk_msg_free_nocharge(struct sock * sk,struct sk_msg * msg)210 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
211 {
212 return __sk_msg_free(sk, msg, msg->sg.start, false);
213 }
214 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
215
sk_msg_free(struct sock * sk,struct sk_msg * msg)216 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
217 {
218 return __sk_msg_free(sk, msg, msg->sg.start, true);
219 }
220 EXPORT_SYMBOL_GPL(sk_msg_free);
221
__sk_msg_free_partial(struct sock * sk,struct sk_msg * msg,u32 bytes,bool charge)222 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
223 u32 bytes, bool charge)
224 {
225 struct scatterlist *sge;
226 u32 i = msg->sg.start;
227
228 while (bytes) {
229 sge = sk_msg_elem(msg, i);
230 if (!sge->length)
231 break;
232 if (bytes < sge->length) {
233 if (charge)
234 sk_mem_uncharge(sk, bytes);
235 sge->length -= bytes;
236 sge->offset += bytes;
237 msg->sg.size -= bytes;
238 break;
239 }
240
241 msg->sg.size -= sge->length;
242 bytes -= sge->length;
243 sk_msg_free_elem(sk, msg, i, charge);
244 sk_msg_iter_var_next(i);
245 sk_msg_check_to_free(msg, i, bytes);
246 }
247 msg->sg.start = i;
248 }
249
sk_msg_free_partial(struct sock * sk,struct sk_msg * msg,u32 bytes)250 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
251 {
252 __sk_msg_free_partial(sk, msg, bytes, true);
253 }
254 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
255
sk_msg_free_partial_nocharge(struct sock * sk,struct sk_msg * msg,u32 bytes)256 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
257 u32 bytes)
258 {
259 __sk_msg_free_partial(sk, msg, bytes, false);
260 }
261
sk_msg_trim(struct sock * sk,struct sk_msg * msg,int len)262 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
263 {
264 int trim = msg->sg.size - len;
265 u32 i = msg->sg.end;
266
267 if (trim <= 0) {
268 WARN_ON(trim < 0);
269 return;
270 }
271
272 sk_msg_iter_var_prev(i);
273 msg->sg.size = len;
274 while (msg->sg.data[i].length &&
275 trim >= msg->sg.data[i].length) {
276 trim -= msg->sg.data[i].length;
277 sk_msg_free_elem(sk, msg, i, true);
278 sk_msg_iter_var_prev(i);
279 if (!trim)
280 goto out;
281 }
282
283 msg->sg.data[i].length -= trim;
284 sk_mem_uncharge(sk, trim);
285 /* Adjust copybreak if it falls into the trimmed part of last buf */
286 if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
287 msg->sg.copybreak = msg->sg.data[i].length;
288 out:
289 sk_msg_iter_var_next(i);
290 msg->sg.end = i;
291
292 /* If we trim data a full sg elem before curr pointer update
293 * copybreak and current so that any future copy operations
294 * start at new copy location.
295 * However trimed data that has not yet been used in a copy op
296 * does not require an update.
297 */
298 if (!msg->sg.size) {
299 msg->sg.curr = msg->sg.start;
300 msg->sg.copybreak = 0;
301 } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
302 sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
303 sk_msg_iter_var_prev(i);
304 msg->sg.curr = i;
305 msg->sg.copybreak = msg->sg.data[i].length;
306 }
307 }
308 EXPORT_SYMBOL_GPL(sk_msg_trim);
309
sk_msg_zerocopy_from_iter(struct sock * sk,struct iov_iter * from,struct sk_msg * msg,u32 bytes)310 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
311 struct sk_msg *msg, u32 bytes)
312 {
313 int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
314 const int to_max_pages = MAX_MSG_FRAGS;
315 struct page *pages[MAX_MSG_FRAGS];
316 ssize_t orig, copied, use, offset;
317
318 orig = msg->sg.size;
319 while (bytes > 0) {
320 i = 0;
321 maxpages = to_max_pages - num_elems;
322 if (maxpages == 0) {
323 ret = -EFAULT;
324 goto out;
325 }
326
327 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
328 &offset);
329 if (copied <= 0) {
330 ret = -EFAULT;
331 goto out;
332 }
333
334 iov_iter_advance(from, copied);
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 }
358 out:
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 }
366 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
367
sk_msg_memcopy_from_iter(struct sock * sk,struct iov_iter * from,struct sk_msg * msg,u32 bytes)368 int 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);
405 out:
406 msg->sg.curr = i;
407 return ret;
408 }
409 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
410
sk_psock_create_ingress_msg(struct sock * sk,struct sk_buff * skb)411 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
412 struct sk_buff *skb)
413 {
414 struct sk_msg *msg;
415
416 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
417 return NULL;
418
419 if (!sk_rmem_schedule(sk, skb, skb->truesize))
420 return NULL;
421
422 msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
423 if (unlikely(!msg))
424 return NULL;
425
426 sk_msg_init(msg);
427 return msg;
428 }
429
sk_psock_skb_ingress_enqueue(struct sk_buff * skb,struct sk_psock * psock,struct sock * sk,struct sk_msg * msg)430 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
431 struct sk_psock *psock,
432 struct sock *sk,
433 struct sk_msg *msg)
434 {
435 int num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
436 int copied;
437
438 if (unlikely(num_sge < 0)) {
439 kfree(msg);
440 return num_sge;
441 }
442
443 copied = skb->len;
444 msg->sg.start = 0;
445 msg->sg.size = copied;
446 msg->sg.end = num_sge;
447 msg->skb = skb;
448
449 sk_psock_queue_msg(psock, msg);
450 sk_psock_data_ready(sk, psock);
451 return copied;
452 }
453
sk_psock_skb_ingress(struct sk_psock * psock,struct sk_buff * skb)454 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
455 {
456 struct sock *sk = psock->sk;
457 struct sk_msg *msg;
458
459 msg = sk_psock_create_ingress_msg(sk, skb);
460 if (!msg)
461 return -EAGAIN;
462
463 /* This will transition ownership of the data from the socket where
464 * the BPF program was run initiating the redirect to the socket
465 * we will eventually receive this data on. The data will be released
466 * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
467 * into user buffers.
468 */
469 skb_set_owner_r(skb, sk);
470 return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
471 }
472
473 /* Puts an skb on the ingress queue of the socket already assigned to the
474 * skb. In this case we do not need to check memory limits or skb_set_owner_r
475 * because the skb is already accounted for here.
476 */
sk_psock_skb_ingress_self(struct sk_psock * psock,struct sk_buff * skb)477 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb)
478 {
479 struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
480 struct sock *sk = psock->sk;
481
482 if (unlikely(!msg))
483 return -EAGAIN;
484 sk_msg_init(msg);
485 return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
486 }
487
sk_psock_handle_skb(struct sk_psock * psock,struct sk_buff * skb,u32 off,u32 len,bool ingress)488 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
489 u32 off, u32 len, bool ingress)
490 {
491 if (ingress)
492 return sk_psock_skb_ingress(psock, skb);
493 else
494 return skb_send_sock_locked(psock->sk, skb, off, len);
495 }
496
sk_psock_backlog(struct work_struct * work)497 static void sk_psock_backlog(struct work_struct *work)
498 {
499 struct sk_psock *psock = container_of(work, struct sk_psock, work);
500 struct sk_psock_work_state *state = &psock->work_state;
501 struct sk_buff *skb;
502 bool ingress;
503 u32 len, off;
504 int ret;
505
506 /* Lock sock to avoid losing sk_socket during loop. */
507 lock_sock(psock->sk);
508 if (state->skb) {
509 skb = state->skb;
510 len = state->len;
511 off = state->off;
512 state->skb = NULL;
513 goto start;
514 }
515
516 while ((skb = skb_dequeue(&psock->ingress_skb))) {
517 len = skb->len;
518 off = 0;
519 start:
520 ingress = tcp_skb_bpf_ingress(skb);
521 do {
522 ret = -EIO;
523 if (likely(psock->sk->sk_socket))
524 ret = sk_psock_handle_skb(psock, skb, off,
525 len, ingress);
526 if (ret <= 0) {
527 if (ret == -EAGAIN) {
528 state->skb = skb;
529 state->len = len;
530 state->off = off;
531 goto end;
532 }
533 /* Hard errors break pipe and stop xmit. */
534 sk_psock_report_error(psock, ret ? -ret : EPIPE);
535 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
536 kfree_skb(skb);
537 goto end;
538 }
539 off += ret;
540 len -= ret;
541 } while (len);
542
543 if (!ingress)
544 kfree_skb(skb);
545 }
546 end:
547 release_sock(psock->sk);
548 }
549
sk_psock_init(struct sock * sk,int node)550 struct sk_psock *sk_psock_init(struct sock *sk, int node)
551 {
552 struct sk_psock *psock = kzalloc_node(sizeof(*psock),
553 GFP_ATOMIC | __GFP_NOWARN,
554 node);
555 if (!psock)
556 return NULL;
557
558 psock->sk = sk;
559 psock->eval = __SK_NONE;
560
561 INIT_LIST_HEAD(&psock->link);
562 spin_lock_init(&psock->link_lock);
563
564 INIT_WORK(&psock->work, sk_psock_backlog);
565 INIT_LIST_HEAD(&psock->ingress_msg);
566 skb_queue_head_init(&psock->ingress_skb);
567
568 sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
569 refcount_set(&psock->refcnt, 1);
570
571 rcu_assign_sk_user_data(sk, psock);
572 sock_hold(sk);
573
574 return psock;
575 }
576 EXPORT_SYMBOL_GPL(sk_psock_init);
577
sk_psock_link_pop(struct sk_psock * psock)578 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
579 {
580 struct sk_psock_link *link;
581
582 spin_lock_bh(&psock->link_lock);
583 link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
584 list);
585 if (link)
586 list_del(&link->list);
587 spin_unlock_bh(&psock->link_lock);
588 return link;
589 }
590
__sk_psock_purge_ingress_msg(struct sk_psock * psock)591 void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
592 {
593 struct sk_msg *msg, *tmp;
594
595 list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
596 list_del(&msg->list);
597 sk_msg_free(psock->sk, msg);
598 kfree(msg);
599 }
600 }
601
sk_psock_zap_ingress(struct sk_psock * psock)602 static void sk_psock_zap_ingress(struct sk_psock *psock)
603 {
604 __skb_queue_purge(&psock->ingress_skb);
605 __sk_psock_purge_ingress_msg(psock);
606 }
607
sk_psock_link_destroy(struct sk_psock * psock)608 static void sk_psock_link_destroy(struct sk_psock *psock)
609 {
610 struct sk_psock_link *link, *tmp;
611
612 list_for_each_entry_safe(link, tmp, &psock->link, list) {
613 list_del(&link->list);
614 sk_psock_free_link(link);
615 }
616 }
617
sk_psock_destroy_deferred(struct work_struct * gc)618 static void sk_psock_destroy_deferred(struct work_struct *gc)
619 {
620 struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
621
622 /* No sk_callback_lock since already detached. */
623
624 /* Parser has been stopped */
625 if (psock->progs.skb_parser)
626 strp_done(&psock->parser.strp);
627
628 cancel_work_sync(&psock->work);
629
630 psock_progs_drop(&psock->progs);
631
632 sk_psock_link_destroy(psock);
633 sk_psock_cork_free(psock);
634 sk_psock_zap_ingress(psock);
635
636 if (psock->sk_redir)
637 sock_put(psock->sk_redir);
638 sock_put(psock->sk);
639 kfree(psock);
640 }
641
sk_psock_destroy(struct rcu_head * rcu)642 void sk_psock_destroy(struct rcu_head *rcu)
643 {
644 struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
645
646 INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
647 schedule_work(&psock->gc);
648 }
649 EXPORT_SYMBOL_GPL(sk_psock_destroy);
650
sk_psock_drop(struct sock * sk,struct sk_psock * psock)651 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
652 {
653 sk_psock_cork_free(psock);
654 sk_psock_zap_ingress(psock);
655
656 write_lock_bh(&sk->sk_callback_lock);
657 sk_psock_restore_proto(sk, psock);
658 rcu_assign_sk_user_data(sk, NULL);
659 if (psock->progs.skb_parser)
660 sk_psock_stop_strp(sk, psock);
661 write_unlock_bh(&sk->sk_callback_lock);
662 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
663
664 call_rcu(&psock->rcu, sk_psock_destroy);
665 }
666 EXPORT_SYMBOL_GPL(sk_psock_drop);
667
sk_psock_map_verd(int verdict,bool redir)668 static int sk_psock_map_verd(int verdict, bool redir)
669 {
670 switch (verdict) {
671 case SK_PASS:
672 return redir ? __SK_REDIRECT : __SK_PASS;
673 case SK_DROP:
674 default:
675 break;
676 }
677
678 return __SK_DROP;
679 }
680
sk_psock_msg_verdict(struct sock * sk,struct sk_psock * psock,struct sk_msg * msg)681 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
682 struct sk_msg *msg)
683 {
684 struct bpf_prog *prog;
685 int ret;
686
687 preempt_disable();
688 rcu_read_lock();
689 prog = READ_ONCE(psock->progs.msg_parser);
690 if (unlikely(!prog)) {
691 ret = __SK_PASS;
692 goto out;
693 }
694
695 sk_msg_compute_data_pointers(msg);
696 msg->sk = sk;
697 ret = BPF_PROG_RUN(prog, msg);
698 ret = sk_psock_map_verd(ret, msg->sk_redir);
699 psock->apply_bytes = msg->apply_bytes;
700 if (ret == __SK_REDIRECT) {
701 if (psock->sk_redir)
702 sock_put(psock->sk_redir);
703 psock->sk_redir = msg->sk_redir;
704 if (!psock->sk_redir) {
705 ret = __SK_DROP;
706 goto out;
707 }
708 sock_hold(psock->sk_redir);
709 }
710 out:
711 rcu_read_unlock();
712 preempt_enable();
713 return ret;
714 }
715 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
716
sk_psock_bpf_run(struct sk_psock * psock,struct bpf_prog * prog,struct sk_buff * skb)717 static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
718 struct sk_buff *skb)
719 {
720 int ret;
721
722 skb->sk = psock->sk;
723 bpf_compute_data_end_sk_skb(skb);
724 preempt_disable();
725 ret = BPF_PROG_RUN(prog, skb);
726 preempt_enable();
727 /* strparser clones the skb before handing it to a upper layer,
728 * meaning skb_orphan has been called. We NULL sk on the way out
729 * to ensure we don't trigger a BUG_ON() in skb/sk operations
730 * later and because we are not charging the memory of this skb
731 * to any socket yet.
732 */
733 skb->sk = NULL;
734 return ret;
735 }
736
sk_psock_from_strp(struct strparser * strp)737 static struct sk_psock *sk_psock_from_strp(struct strparser *strp)
738 {
739 struct sk_psock_parser *parser;
740
741 parser = container_of(strp, struct sk_psock_parser, strp);
742 return container_of(parser, struct sk_psock, parser);
743 }
744
sk_psock_skb_redirect(struct sk_buff * skb)745 static void sk_psock_skb_redirect(struct sk_buff *skb)
746 {
747 struct sk_psock *psock_other;
748 struct sock *sk_other;
749 bool ingress;
750
751 sk_other = tcp_skb_bpf_redirect_fetch(skb);
752 if (unlikely(!sk_other)) {
753 kfree_skb(skb);
754 return;
755 }
756 psock_other = sk_psock(sk_other);
757 if (!psock_other || sock_flag(sk_other, SOCK_DEAD) ||
758 !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
759 kfree_skb(skb);
760 return;
761 }
762
763 ingress = tcp_skb_bpf_ingress(skb);
764 if ((!ingress && sock_writeable(sk_other)) ||
765 (ingress &&
766 atomic_read(&sk_other->sk_rmem_alloc) <=
767 sk_other->sk_rcvbuf)) {
768 if (!ingress)
769 skb_set_owner_w(skb, sk_other);
770 skb_queue_tail(&psock_other->ingress_skb, skb);
771 schedule_work(&psock_other->work);
772 } else {
773 kfree_skb(skb);
774 }
775 }
776
sk_psock_tls_verdict_apply(struct sk_buff * skb,int verdict)777 static void sk_psock_tls_verdict_apply(struct sk_buff *skb, int verdict)
778 {
779 switch (verdict) {
780 case __SK_REDIRECT:
781 sk_psock_skb_redirect(skb);
782 break;
783 case __SK_PASS:
784 case __SK_DROP:
785 default:
786 break;
787 }
788 }
789
sk_psock_tls_strp_read(struct sk_psock * psock,struct sk_buff * skb)790 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
791 {
792 struct bpf_prog *prog;
793 int ret = __SK_PASS;
794
795 rcu_read_lock();
796 prog = READ_ONCE(psock->progs.skb_verdict);
797 if (likely(prog)) {
798 tcp_skb_bpf_redirect_clear(skb);
799 ret = sk_psock_bpf_run(psock, prog, skb);
800 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
801 }
802 sk_psock_tls_verdict_apply(skb, ret);
803 rcu_read_unlock();
804 return ret;
805 }
806 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
807
sk_psock_verdict_apply(struct sk_psock * psock,struct sk_buff * skb,int verdict)808 static void sk_psock_verdict_apply(struct sk_psock *psock,
809 struct sk_buff *skb, int verdict)
810 {
811 struct tcp_skb_cb *tcp;
812 struct sock *sk_other;
813 int err = -EIO;
814
815 switch (verdict) {
816 case __SK_PASS:
817 sk_other = psock->sk;
818 if (sock_flag(sk_other, SOCK_DEAD) ||
819 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
820 goto out_free;
821 }
822
823 tcp = TCP_SKB_CB(skb);
824 tcp->bpf.flags |= BPF_F_INGRESS;
825
826 /* If the queue is empty then we can submit directly
827 * into the msg queue. If its not empty we have to
828 * queue work otherwise we may get OOO data. Otherwise,
829 * if sk_psock_skb_ingress errors will be handled by
830 * retrying later from workqueue.
831 */
832 if (skb_queue_empty(&psock->ingress_skb)) {
833 err = sk_psock_skb_ingress_self(psock, skb);
834 }
835 if (err < 0) {
836 skb_queue_tail(&psock->ingress_skb, skb);
837 schedule_work(&psock->work);
838 }
839 break;
840 case __SK_REDIRECT:
841 sk_psock_skb_redirect(skb);
842 break;
843 case __SK_DROP:
844 /* fall-through */
845 default:
846 out_free:
847 kfree_skb(skb);
848 }
849 }
850
sk_psock_strp_read(struct strparser * strp,struct sk_buff * skb)851 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
852 {
853 struct sk_psock *psock;
854 struct bpf_prog *prog;
855 int ret = __SK_DROP;
856 struct sock *sk;
857
858 rcu_read_lock();
859 sk = strp->sk;
860 psock = sk_psock(sk);
861 if (unlikely(!psock)) {
862 kfree_skb(skb);
863 goto out;
864 }
865 prog = READ_ONCE(psock->progs.skb_verdict);
866 if (likely(prog)) {
867 skb_orphan(skb);
868 tcp_skb_bpf_redirect_clear(skb);
869 ret = sk_psock_bpf_run(psock, prog, skb);
870 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
871 }
872 sk_psock_verdict_apply(psock, skb, ret);
873 out:
874 rcu_read_unlock();
875 }
876
sk_psock_strp_read_done(struct strparser * strp,int err)877 static int sk_psock_strp_read_done(struct strparser *strp, int err)
878 {
879 return err;
880 }
881
sk_psock_strp_parse(struct strparser * strp,struct sk_buff * skb)882 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
883 {
884 struct sk_psock *psock = sk_psock_from_strp(strp);
885 struct bpf_prog *prog;
886 int ret = skb->len;
887
888 rcu_read_lock();
889 prog = READ_ONCE(psock->progs.skb_parser);
890 if (likely(prog))
891 ret = sk_psock_bpf_run(psock, prog, skb);
892 rcu_read_unlock();
893 return ret;
894 }
895
896 /* Called with socket lock held. */
sk_psock_strp_data_ready(struct sock * sk)897 static void sk_psock_strp_data_ready(struct sock *sk)
898 {
899 struct sk_psock *psock;
900
901 rcu_read_lock();
902 psock = sk_psock(sk);
903 if (likely(psock)) {
904 if (tls_sw_has_ctx_rx(sk)) {
905 psock->parser.saved_data_ready(sk);
906 } else {
907 write_lock_bh(&sk->sk_callback_lock);
908 strp_data_ready(&psock->parser.strp);
909 write_unlock_bh(&sk->sk_callback_lock);
910 }
911 }
912 rcu_read_unlock();
913 }
914
sk_psock_write_space(struct sock * sk)915 static void sk_psock_write_space(struct sock *sk)
916 {
917 struct sk_psock *psock;
918 void (*write_space)(struct sock *sk) = NULL;
919
920 rcu_read_lock();
921 psock = sk_psock(sk);
922 if (likely(psock)) {
923 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
924 schedule_work(&psock->work);
925 write_space = psock->saved_write_space;
926 }
927 rcu_read_unlock();
928 if (write_space)
929 write_space(sk);
930 }
931
sk_psock_init_strp(struct sock * sk,struct sk_psock * psock)932 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
933 {
934 static const struct strp_callbacks cb = {
935 .rcv_msg = sk_psock_strp_read,
936 .read_sock_done = sk_psock_strp_read_done,
937 .parse_msg = sk_psock_strp_parse,
938 };
939
940 psock->parser.enabled = false;
941 return strp_init(&psock->parser.strp, sk, &cb);
942 }
943
sk_psock_start_strp(struct sock * sk,struct sk_psock * psock)944 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
945 {
946 struct sk_psock_parser *parser = &psock->parser;
947
948 if (parser->enabled)
949 return;
950
951 parser->saved_data_ready = sk->sk_data_ready;
952 sk->sk_data_ready = sk_psock_strp_data_ready;
953 sk->sk_write_space = sk_psock_write_space;
954 parser->enabled = true;
955 }
956
sk_psock_stop_strp(struct sock * sk,struct sk_psock * psock)957 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
958 {
959 struct sk_psock_parser *parser = &psock->parser;
960
961 if (!parser->enabled)
962 return;
963
964 sk->sk_data_ready = parser->saved_data_ready;
965 parser->saved_data_ready = NULL;
966 strp_stop(&parser->strp);
967 parser->enabled = false;
968 }
969