1
2
3
4#include <linux/skmsg.h>
5#include <linux/filter.h>
6#include <linux/bpf.h>
7#include <linux/init.h>
8#include <linux/wait.h>
9
10#include <net/inet_common.h>
11#include <net/tls.h>
12
13static bool tcp_bpf_stream_read(const struct sock *sk)
14{
15 struct sk_psock *psock;
16 bool empty = true;
17
18 rcu_read_lock();
19 psock = sk_psock(sk);
20 if (likely(psock))
21 empty = list_empty(&psock->ingress_msg);
22 rcu_read_unlock();
23 return !empty;
24}
25
26static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
27 int flags, long timeo, int *err)
28{
29 DEFINE_WAIT_FUNC(wait, woken_wake_function);
30 int ret = 0;
31
32 if (!timeo)
33 return ret;
34
35 add_wait_queue(sk_sleep(sk), &wait);
36 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
37 ret = sk_wait_event(sk, &timeo,
38 !list_empty(&psock->ingress_msg) ||
39 !skb_queue_empty(&sk->sk_receive_queue), &wait);
40 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
41 remove_wait_queue(sk_sleep(sk), &wait);
42 return ret;
43}
44
45int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
46 struct msghdr *msg, int len, int flags)
47{
48 struct iov_iter *iter = &msg->msg_iter;
49 int peek = flags & MSG_PEEK;
50 int i, ret, copied = 0;
51 struct sk_msg *msg_rx;
52
53 msg_rx = list_first_entry_or_null(&psock->ingress_msg,
54 struct sk_msg, list);
55
56 while (copied != len) {
57 struct scatterlist *sge;
58
59 if (unlikely(!msg_rx))
60 break;
61
62 i = msg_rx->sg.start;
63 do {
64 struct page *page;
65 int copy;
66
67 sge = sk_msg_elem(msg_rx, i);
68 copy = sge->length;
69 page = sg_page(sge);
70 if (copied + copy > len)
71 copy = len - copied;
72 ret = copy_page_to_iter(page, sge->offset, copy, iter);
73 if (ret != copy) {
74 msg_rx->sg.start = i;
75 return -EFAULT;
76 }
77
78 copied += copy;
79 if (likely(!peek)) {
80 sge->offset += copy;
81 sge->length -= copy;
82 sk_mem_uncharge(sk, copy);
83 msg_rx->sg.size -= copy;
84
85 if (!sge->length) {
86 sk_msg_iter_var_next(i);
87 if (!msg_rx->skb)
88 put_page(page);
89 }
90 } else {
91 sk_msg_iter_var_next(i);
92 }
93
94 if (copied == len)
95 break;
96 } while (i != msg_rx->sg.end);
97
98 if (unlikely(peek)) {
99 msg_rx = list_next_entry(msg_rx, list);
100 continue;
101 }
102
103 msg_rx->sg.start = i;
104 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
105 list_del(&msg_rx->list);
106 if (msg_rx->skb)
107 consume_skb(msg_rx->skb);
108 kfree(msg_rx);
109 }
110 msg_rx = list_first_entry_or_null(&psock->ingress_msg,
111 struct sk_msg, list);
112 }
113
114 return copied;
115}
116EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg);
117
118int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
119 int nonblock, int flags, int *addr_len)
120{
121 struct sk_psock *psock;
122 int copied, ret;
123
124 psock = sk_psock_get(sk);
125 if (unlikely(!psock))
126 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
127 if (unlikely(flags & MSG_ERRQUEUE))
128 return inet_recv_error(sk, msg, len, addr_len);
129 if (!skb_queue_empty(&sk->sk_receive_queue) &&
130 sk_psock_queue_empty(psock))
131 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
132 lock_sock(sk);
133msg_bytes_ready:
134 copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
135 if (!copied) {
136 int data, err = 0;
137 long timeo;
138
139 timeo = sock_rcvtimeo(sk, nonblock);
140 data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
141 if (data) {
142 if (!sk_psock_queue_empty(psock))
143 goto msg_bytes_ready;
144 release_sock(sk);
145 sk_psock_put(sk, psock);
146 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
147 }
148 if (err) {
149 ret = err;
150 goto out;
151 }
152 copied = -EAGAIN;
153 }
154 ret = copied;
155out:
156 release_sock(sk);
157 sk_psock_put(sk, psock);
158 return ret;
159}
160
161static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
162 struct sk_msg *msg, u32 apply_bytes, int flags)
163{
164 bool apply = apply_bytes;
165 struct scatterlist *sge;
166 u32 size, copied = 0;
167 struct sk_msg *tmp;
168 int i, ret = 0;
169
170 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL);
171 if (unlikely(!tmp))
172 return -ENOMEM;
173
174 lock_sock(sk);
175 tmp->sg.start = msg->sg.start;
176 i = msg->sg.start;
177 do {
178 sge = sk_msg_elem(msg, i);
179 size = (apply && apply_bytes < sge->length) ?
180 apply_bytes : sge->length;
181 if (!sk_wmem_schedule(sk, size)) {
182 if (!copied)
183 ret = -ENOMEM;
184 break;
185 }
186
187 sk_mem_charge(sk, size);
188 sk_msg_xfer(tmp, msg, i, size);
189 copied += size;
190 if (sge->length)
191 get_page(sk_msg_page(tmp, i));
192 sk_msg_iter_var_next(i);
193 tmp->sg.end = i;
194 if (apply) {
195 apply_bytes -= size;
196 if (!apply_bytes)
197 break;
198 }
199 } while (i != msg->sg.end);
200
201 if (!ret) {
202 msg->sg.start = i;
203 msg->sg.size -= apply_bytes;
204 sk_psock_queue_msg(psock, tmp);
205 sk_psock_data_ready(sk, psock);
206 } else {
207 sk_msg_free(sk, tmp);
208 kfree(tmp);
209 }
210
211 release_sock(sk);
212 return ret;
213}
214
215static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
216 int flags, bool uncharge)
217{
218 bool apply = apply_bytes;
219 struct scatterlist *sge;
220 struct page *page;
221 int size, ret = 0;
222 u32 off;
223
224 while (1) {
225 bool has_tx_ulp;
226
227 sge = sk_msg_elem(msg, msg->sg.start);
228 size = (apply && apply_bytes < sge->length) ?
229 apply_bytes : sge->length;
230 off = sge->offset;
231 page = sg_page(sge);
232
233 tcp_rate_check_app_limited(sk);
234retry:
235 has_tx_ulp = tls_sw_has_ctx_tx(sk);
236 if (has_tx_ulp) {
237 flags |= MSG_SENDPAGE_NOPOLICY;
238 ret = kernel_sendpage_locked(sk,
239 page, off, size, flags);
240 } else {
241 ret = do_tcp_sendpages(sk, page, off, size, flags);
242 }
243
244 if (ret <= 0)
245 return ret;
246 if (apply)
247 apply_bytes -= ret;
248 msg->sg.size -= ret;
249 sge->offset += ret;
250 sge->length -= ret;
251 if (uncharge)
252 sk_mem_uncharge(sk, ret);
253 if (ret != size) {
254 size -= ret;
255 off += ret;
256 goto retry;
257 }
258 if (!sge->length) {
259 put_page(page);
260 sk_msg_iter_next(msg, start);
261 sg_init_table(sge, 1);
262 if (msg->sg.start == msg->sg.end)
263 break;
264 }
265 if (apply && !apply_bytes)
266 break;
267 }
268
269 return 0;
270}
271
272static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
273 u32 apply_bytes, int flags, bool uncharge)
274{
275 int ret;
276
277 lock_sock(sk);
278 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
279 release_sock(sk);
280 return ret;
281}
282
283int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg,
284 u32 bytes, int flags)
285{
286 bool ingress = sk_msg_to_ingress(msg);
287 struct sk_psock *psock = sk_psock_get(sk);
288 int ret;
289
290 if (unlikely(!psock)) {
291 sk_msg_free(sk, msg);
292 return 0;
293 }
294 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) :
295 tcp_bpf_push_locked(sk, msg, bytes, flags, false);
296 sk_psock_put(sk, psock);
297 return ret;
298}
299EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
300
301static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
302 struct sk_msg *msg, int *copied, int flags)
303{
304 bool cork = false, enospc = sk_msg_full(msg);
305 struct sock *sk_redir;
306 u32 tosend, delta = 0;
307 int ret;
308
309more_data:
310 if (psock->eval == __SK_NONE) {
311
312
313
314
315
316 delta = msg->sg.size;
317 psock->eval = sk_psock_msg_verdict(sk, psock, msg);
318 delta -= msg->sg.size;
319 }
320
321 if (msg->cork_bytes &&
322 msg->cork_bytes > msg->sg.size && !enospc) {
323 psock->cork_bytes = msg->cork_bytes - msg->sg.size;
324 if (!psock->cork) {
325 psock->cork = kzalloc(sizeof(*psock->cork),
326 GFP_ATOMIC | __GFP_NOWARN);
327 if (!psock->cork)
328 return -ENOMEM;
329 }
330 memcpy(psock->cork, msg, sizeof(*msg));
331 return 0;
332 }
333
334 tosend = msg->sg.size;
335 if (psock->apply_bytes && psock->apply_bytes < tosend)
336 tosend = psock->apply_bytes;
337
338 switch (psock->eval) {
339 case __SK_PASS:
340 ret = tcp_bpf_push(sk, msg, tosend, flags, true);
341 if (unlikely(ret)) {
342 *copied -= sk_msg_free(sk, msg);
343 break;
344 }
345 sk_msg_apply_bytes(psock, tosend);
346 break;
347 case __SK_REDIRECT:
348 sk_redir = psock->sk_redir;
349 sk_msg_apply_bytes(psock, tosend);
350 if (psock->cork) {
351 cork = true;
352 psock->cork = NULL;
353 }
354 sk_msg_return(sk, msg, tosend);
355 release_sock(sk);
356 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags);
357 lock_sock(sk);
358 if (unlikely(ret < 0)) {
359 int free = sk_msg_free_nocharge(sk, msg);
360
361 if (!cork)
362 *copied -= free;
363 }
364 if (cork) {
365 sk_msg_free(sk, msg);
366 kfree(msg);
367 msg = NULL;
368 ret = 0;
369 }
370 break;
371 case __SK_DROP:
372 default:
373 sk_msg_free_partial(sk, msg, tosend);
374 sk_msg_apply_bytes(psock, tosend);
375 *copied -= (tosend + delta);
376 return -EACCES;
377 }
378
379 if (likely(!ret)) {
380 if (!psock->apply_bytes) {
381 psock->eval = __SK_NONE;
382 if (psock->sk_redir) {
383 sock_put(psock->sk_redir);
384 psock->sk_redir = NULL;
385 }
386 }
387 if (msg &&
388 msg->sg.data[msg->sg.start].page_link &&
389 msg->sg.data[msg->sg.start].length)
390 goto more_data;
391 }
392 return ret;
393}
394
395static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
396{
397 struct sk_msg tmp, *msg_tx = NULL;
398 int copied = 0, err = 0;
399 struct sk_psock *psock;
400 long timeo;
401 int flags;
402
403
404 flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED);
405 flags |= MSG_NO_SHARED_FRAGS;
406
407 psock = sk_psock_get(sk);
408 if (unlikely(!psock))
409 return tcp_sendmsg(sk, msg, size);
410
411 lock_sock(sk);
412 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
413 while (msg_data_left(msg)) {
414 bool enospc = false;
415 u32 copy, osize;
416
417 if (sk->sk_err) {
418 err = -sk->sk_err;
419 goto out_err;
420 }
421
422 copy = msg_data_left(msg);
423 if (!sk_stream_memory_free(sk))
424 goto wait_for_sndbuf;
425 if (psock->cork) {
426 msg_tx = psock->cork;
427 } else {
428 msg_tx = &tmp;
429 sk_msg_init(msg_tx);
430 }
431
432 osize = msg_tx->sg.size;
433 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
434 if (err) {
435 if (err != -ENOSPC)
436 goto wait_for_memory;
437 enospc = true;
438 copy = msg_tx->sg.size - osize;
439 }
440
441 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
442 copy);
443 if (err < 0) {
444 sk_msg_trim(sk, msg_tx, osize);
445 goto out_err;
446 }
447
448 copied += copy;
449 if (psock->cork_bytes) {
450 if (size > psock->cork_bytes)
451 psock->cork_bytes = 0;
452 else
453 psock->cork_bytes -= size;
454 if (psock->cork_bytes && !enospc)
455 goto out_err;
456
457 psock->eval = __SK_NONE;
458 psock->cork_bytes = 0;
459 }
460
461 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
462 if (unlikely(err < 0))
463 goto out_err;
464 continue;
465wait_for_sndbuf:
466 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
467wait_for_memory:
468 err = sk_stream_wait_memory(sk, &timeo);
469 if (err) {
470 if (msg_tx && msg_tx != psock->cork)
471 sk_msg_free(sk, msg_tx);
472 goto out_err;
473 }
474 }
475out_err:
476 if (err < 0)
477 err = sk_stream_error(sk, msg->msg_flags, err);
478 release_sock(sk);
479 sk_psock_put(sk, psock);
480 return copied ? copied : err;
481}
482
483static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset,
484 size_t size, int flags)
485{
486 struct sk_msg tmp, *msg = NULL;
487 int err = 0, copied = 0;
488 struct sk_psock *psock;
489 bool enospc = false;
490
491 psock = sk_psock_get(sk);
492 if (unlikely(!psock))
493 return tcp_sendpage(sk, page, offset, size, flags);
494
495 lock_sock(sk);
496 if (psock->cork) {
497 msg = psock->cork;
498 } else {
499 msg = &tmp;
500 sk_msg_init(msg);
501 }
502
503
504 if (unlikely(sk_msg_full(msg)))
505 goto out_err;
506
507 sk_msg_page_add(msg, page, size, offset);
508 sk_mem_charge(sk, size);
509 copied = size;
510 if (sk_msg_full(msg))
511 enospc = true;
512 if (psock->cork_bytes) {
513 if (size > psock->cork_bytes)
514 psock->cork_bytes = 0;
515 else
516 psock->cork_bytes -= size;
517 if (psock->cork_bytes && !enospc)
518 goto out_err;
519
520 psock->eval = __SK_NONE;
521 psock->cork_bytes = 0;
522 }
523
524 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags);
525out_err:
526 release_sock(sk);
527 sk_psock_put(sk, psock);
528 return copied ? copied : err;
529}
530
531static void tcp_bpf_remove(struct sock *sk, struct sk_psock *psock)
532{
533 struct sk_psock_link *link;
534
535 while ((link = sk_psock_link_pop(psock))) {
536 sk_psock_unlink(sk, link);
537 sk_psock_free_link(link);
538 }
539}
540
541static void tcp_bpf_unhash(struct sock *sk)
542{
543 void (*saved_unhash)(struct sock *sk);
544 struct sk_psock *psock;
545
546 rcu_read_lock();
547 psock = sk_psock(sk);
548 if (unlikely(!psock)) {
549 rcu_read_unlock();
550 if (sk->sk_prot->unhash)
551 sk->sk_prot->unhash(sk);
552 return;
553 }
554
555 saved_unhash = psock->saved_unhash;
556 tcp_bpf_remove(sk, psock);
557 rcu_read_unlock();
558 saved_unhash(sk);
559}
560
561static void tcp_bpf_close(struct sock *sk, long timeout)
562{
563 void (*saved_close)(struct sock *sk, long timeout);
564 struct sk_psock *psock;
565
566 lock_sock(sk);
567 rcu_read_lock();
568 psock = sk_psock(sk);
569 if (unlikely(!psock)) {
570 rcu_read_unlock();
571 release_sock(sk);
572 return sk->sk_prot->close(sk, timeout);
573 }
574
575 saved_close = psock->saved_close;
576 tcp_bpf_remove(sk, psock);
577 rcu_read_unlock();
578 release_sock(sk);
579 saved_close(sk, timeout);
580}
581
582enum {
583 TCP_BPF_IPV4,
584 TCP_BPF_IPV6,
585 TCP_BPF_NUM_PROTS,
586};
587
588enum {
589 TCP_BPF_BASE,
590 TCP_BPF_TX,
591 TCP_BPF_NUM_CFGS,
592};
593
594static struct proto *tcpv6_prot_saved __read_mostly;
595static DEFINE_SPINLOCK(tcpv6_prot_lock);
596static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
597
598static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
599 struct proto *base)
600{
601 prot[TCP_BPF_BASE] = *base;
602 prot[TCP_BPF_BASE].unhash = tcp_bpf_unhash;
603 prot[TCP_BPF_BASE].close = tcp_bpf_close;
604 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg;
605 prot[TCP_BPF_BASE].stream_memory_read = tcp_bpf_stream_read;
606
607 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE];
608 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg;
609 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage;
610}
611
612static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
613{
614 if (sk->sk_family == AF_INET6 &&
615 unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
616 spin_lock_bh(&tcpv6_prot_lock);
617 if (likely(ops != tcpv6_prot_saved)) {
618 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
619 smp_store_release(&tcpv6_prot_saved, ops);
620 }
621 spin_unlock_bh(&tcpv6_prot_lock);
622 }
623}
624
625static int __init tcp_bpf_v4_build_proto(void)
626{
627 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
628 return 0;
629}
630core_initcall(tcp_bpf_v4_build_proto);
631
632static void tcp_bpf_update_sk_prot(struct sock *sk, struct sk_psock *psock)
633{
634 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
635 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
636
637 sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config]);
638}
639
640static void tcp_bpf_reinit_sk_prot(struct sock *sk, struct sk_psock *psock)
641{
642 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
643 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
644
645
646
647
648
649 sk->sk_prot = &tcp_bpf_prots[family][config];
650}
651
652static int tcp_bpf_assert_proto_ops(struct proto *ops)
653{
654
655
656
657
658 return ops->recvmsg == tcp_recvmsg &&
659 ops->sendmsg == tcp_sendmsg &&
660 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP;
661}
662
663void tcp_bpf_reinit(struct sock *sk)
664{
665 struct sk_psock *psock;
666
667 sock_owned_by_me(sk);
668
669 rcu_read_lock();
670 psock = sk_psock(sk);
671 tcp_bpf_reinit_sk_prot(sk, psock);
672 rcu_read_unlock();
673}
674
675int tcp_bpf_init(struct sock *sk)
676{
677 struct proto *ops = READ_ONCE(sk->sk_prot);
678 struct sk_psock *psock;
679
680 sock_owned_by_me(sk);
681
682 rcu_read_lock();
683 psock = sk_psock(sk);
684 if (unlikely(!psock || psock->sk_proto ||
685 tcp_bpf_assert_proto_ops(ops))) {
686 rcu_read_unlock();
687 return -EINVAL;
688 }
689 tcp_bpf_check_v6_needs_rebuild(sk, ops);
690 tcp_bpf_update_sk_prot(sk, psock);
691 rcu_read_unlock();
692 return 0;
693}
694
