aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/tcp_bpf.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/tcp_bpf.c')
-rw-r--r--net/ipv4/tcp_bpf.c655
1 files changed, 655 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
new file mode 100644
index 000000000000..80debb0daf37
--- /dev/null
+++ b/net/ipv4/tcp_bpf.c
@@ -0,0 +1,655 @@
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
3
4#include <linux/skmsg.h>
5#include <linux/filter.h>
6#include <linux/bpf.h>
7#include <linux/init.h>
8#include <linux/wait.h>
9
10#include <net/inet_common.h>
11
12static bool tcp_bpf_stream_read(const struct sock *sk)
13{
14 struct sk_psock *psock;
15 bool empty = true;
16
17 rcu_read_lock();
18 psock = sk_psock(sk);
19 if (likely(psock))
20 empty = list_empty(&psock->ingress_msg);
21 rcu_read_unlock();
22 return !empty;
23}
24
25static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
26 int flags, long timeo, int *err)
27{
28 DEFINE_WAIT_FUNC(wait, woken_wake_function);
29 int ret;
30
31 add_wait_queue(sk_sleep(sk), &wait);
32 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
33 ret = sk_wait_event(sk, &timeo,
34 !list_empty(&psock->ingress_msg) ||
35 !skb_queue_empty(&sk->sk_receive_queue), &wait);
36 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
37 remove_wait_queue(sk_sleep(sk), &wait);
38 return ret;
39}
40
41int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
42 struct msghdr *msg, int len)
43{
44 struct iov_iter *iter = &msg->msg_iter;
45 int i, ret, copied = 0;
46
47 while (copied != len) {
48 struct scatterlist *sge;
49 struct sk_msg *msg_rx;
50
51 msg_rx = list_first_entry_or_null(&psock->ingress_msg,
52 struct sk_msg, list);
53 if (unlikely(!msg_rx))
54 break;
55
56 i = msg_rx->sg.start;
57 do {
58 struct page *page;
59 int copy;
60
61 sge = sk_msg_elem(msg_rx, i);
62 copy = sge->length;
63 page = sg_page(sge);
64 if (copied + copy > len)
65 copy = len - copied;
66 ret = copy_page_to_iter(page, sge->offset, copy, iter);
67 if (ret != copy) {
68 msg_rx->sg.start = i;
69 return -EFAULT;
70 }
71
72 copied += copy;
73 sge->offset += copy;
74 sge->length -= copy;
75 sk_mem_uncharge(sk, copy);
76 if (!sge->length) {
77 i++;
78 if (i == MAX_SKB_FRAGS)
79 i = 0;
80 if (!msg_rx->skb)
81 put_page(page);
82 }
83
84 if (copied == len)
85 break;
86 } while (i != msg_rx->sg.end);
87
88 msg_rx->sg.start = i;
89 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
90 list_del(&msg_rx->list);
91 if (msg_rx->skb)
92 consume_skb(msg_rx->skb);
93 kfree(msg_rx);
94 }
95 }
96
97 return copied;
98}
99EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg);
100
101int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
102 int nonblock, int flags, int *addr_len)
103{
104 struct sk_psock *psock;
105 int copied, ret;
106
107 if (unlikely(flags & MSG_ERRQUEUE))
108 return inet_recv_error(sk, msg, len, addr_len);
109 if (!skb_queue_empty(&sk->sk_receive_queue))
110 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
111
112 psock = sk_psock_get(sk);
113 if (unlikely(!psock))
114 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
115 lock_sock(sk);
116msg_bytes_ready:
117 copied = __tcp_bpf_recvmsg(sk, psock, msg, len);
118 if (!copied) {
119 int data, err = 0;
120 long timeo;
121
122 timeo = sock_rcvtimeo(sk, nonblock);
123 data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
124 if (data) {
125 if (skb_queue_empty(&sk->sk_receive_queue))
126 goto msg_bytes_ready;
127 release_sock(sk);
128 sk_psock_put(sk, psock);
129 return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
130 }
131 if (err) {
132 ret = err;
133 goto out;
134 }
135 }
136 ret = copied;
137out:
138 release_sock(sk);
139 sk_psock_put(sk, psock);
140 return ret;
141}
142
143static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
144 struct sk_msg *msg, u32 apply_bytes, int flags)
145{
146 bool apply = apply_bytes;
147 struct scatterlist *sge;
148 u32 size, copied = 0;
149 struct sk_msg *tmp;
150 int i, ret = 0;
151
152 tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL);
153 if (unlikely(!tmp))
154 return -ENOMEM;
155
156 lock_sock(sk);
157 tmp->sg.start = msg->sg.start;
158 i = msg->sg.start;
159 do {
160 sge = sk_msg_elem(msg, i);
161 size = (apply && apply_bytes < sge->length) ?
162 apply_bytes : sge->length;
163 if (!sk_wmem_schedule(sk, size)) {
164 if (!copied)
165 ret = -ENOMEM;
166 break;
167 }
168
169 sk_mem_charge(sk, size);
170 sk_msg_xfer(tmp, msg, i, size);
171 copied += size;
172 if (sge->length)
173 get_page(sk_msg_page(tmp, i));
174 sk_msg_iter_var_next(i);
175 tmp->sg.end = i;
176 if (apply) {
177 apply_bytes -= size;
178 if (!apply_bytes)
179 break;
180 }
181 } while (i != msg->sg.end);
182
183 if (!ret) {
184 msg->sg.start = i;
185 msg->sg.size -= apply_bytes;
186 sk_psock_queue_msg(psock, tmp);
187 sk->sk_data_ready(sk);
188 } else {
189 sk_msg_free(sk, tmp);
190 kfree(tmp);
191 }
192
193 release_sock(sk);
194 return ret;
195}
196
197static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
198 int flags, bool uncharge)
199{
200 bool apply = apply_bytes;
201 struct scatterlist *sge;
202 struct page *page;
203 int size, ret = 0;
204 u32 off;
205
206 while (1) {
207 sge = sk_msg_elem(msg, msg->sg.start);
208 size = (apply && apply_bytes < sge->length) ?
209 apply_bytes : sge->length;
210 off = sge->offset;
211 page = sg_page(sge);
212
213 tcp_rate_check_app_limited(sk);
214retry:
215 ret = do_tcp_sendpages(sk, page, off, size, flags);
216 if (ret <= 0)
217 return ret;
218 if (apply)
219 apply_bytes -= ret;
220 msg->sg.size -= ret;
221 sge->offset += ret;
222 sge->length -= ret;
223 if (uncharge)
224 sk_mem_uncharge(sk, ret);
225 if (ret != size) {
226 size -= ret;
227 off += ret;
228 goto retry;
229 }
230 if (!sge->length) {
231 put_page(page);
232 sk_msg_iter_next(msg, start);
233 sg_init_table(sge, 1);
234 if (msg->sg.start == msg->sg.end)
235 break;
236 }
237 if (apply && !apply_bytes)
238 break;
239 }
240
241 return 0;
242}
243
244static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
245 u32 apply_bytes, int flags, bool uncharge)
246{
247 int ret;
248
249 lock_sock(sk);
250 ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
251 release_sock(sk);
252 return ret;
253}
254
255int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg,
256 u32 bytes, int flags)
257{
258 bool ingress = sk_msg_to_ingress(msg);
259 struct sk_psock *psock = sk_psock_get(sk);
260 int ret;
261
262 if (unlikely(!psock)) {
263 sk_msg_free(sk, msg);
264 return 0;
265 }
266 ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) :
267 tcp_bpf_push_locked(sk, msg, bytes, flags, false);
268 sk_psock_put(sk, psock);
269 return ret;
270}
271EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
272
273static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
274 struct sk_msg *msg, int *copied, int flags)
275{
276 bool cork = false, enospc = msg->sg.start == msg->sg.end;
277 struct sock *sk_redir;
278 u32 tosend;
279 int ret;
280
281more_data:
282 if (psock->eval == __SK_NONE)
283 psock->eval = sk_psock_msg_verdict(sk, psock, msg);
284
285 if (msg->cork_bytes &&
286 msg->cork_bytes > msg->sg.size && !enospc) {
287 psock->cork_bytes = msg->cork_bytes - msg->sg.size;
288 if (!psock->cork) {
289 psock->cork = kzalloc(sizeof(*psock->cork),
290 GFP_ATOMIC | __GFP_NOWARN);
291 if (!psock->cork)
292 return -ENOMEM;
293 }
294 memcpy(psock->cork, msg, sizeof(*msg));
295 return 0;
296 }
297
298 tosend = msg->sg.size;
299 if (psock->apply_bytes && psock->apply_bytes < tosend)
300 tosend = psock->apply_bytes;
301
302 switch (psock->eval) {
303 case __SK_PASS:
304 ret = tcp_bpf_push(sk, msg, tosend, flags, true);
305 if (unlikely(ret)) {
306 *copied -= sk_msg_free(sk, msg);
307 break;
308 }
309 sk_msg_apply_bytes(psock, tosend);
310 break;
311 case __SK_REDIRECT:
312 sk_redir = psock->sk_redir;
313 sk_msg_apply_bytes(psock, tosend);
314 if (psock->cork) {
315 cork = true;
316 psock->cork = NULL;
317 }
318 sk_msg_return(sk, msg, tosend);
319 release_sock(sk);
320 ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags);
321 lock_sock(sk);
322 if (unlikely(ret < 0)) {
323 int free = sk_msg_free_nocharge(sk, msg);
324
325 if (!cork)
326 *copied -= free;
327 }
328 if (cork) {
329 sk_msg_free(sk, msg);
330 kfree(msg);
331 msg = NULL;
332 ret = 0;
333 }
334 break;
335 case __SK_DROP:
336 default:
337 sk_msg_free_partial(sk, msg, tosend);
338 sk_msg_apply_bytes(psock, tosend);
339 *copied -= tosend;
340 return -EACCES;
341 }
342
343 if (likely(!ret)) {
344 if (!psock->apply_bytes) {
345 psock->eval = __SK_NONE;
346 if (psock->sk_redir) {
347 sock_put(psock->sk_redir);
348 psock->sk_redir = NULL;
349 }
350 }
351 if (msg &&
352 msg->sg.data[msg->sg.start].page_link &&
353 msg->sg.data[msg->sg.start].length)
354 goto more_data;
355 }
356 return ret;
357}
358
359static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
360{
361 struct sk_msg tmp, *msg_tx = NULL;
362 int flags = msg->msg_flags | MSG_NO_SHARED_FRAGS;
363 int copied = 0, err = 0;
364 struct sk_psock *psock;
365 long timeo;
366
367 psock = sk_psock_get(sk);
368 if (unlikely(!psock))
369 return tcp_sendmsg(sk, msg, size);
370
371 lock_sock(sk);
372 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
373 while (msg_data_left(msg)) {
374 bool enospc = false;
375 u32 copy, osize;
376
377 if (sk->sk_err) {
378 err = -sk->sk_err;
379 goto out_err;
380 }
381
382 copy = msg_data_left(msg);
383 if (!sk_stream_memory_free(sk))
384 goto wait_for_sndbuf;
385 if (psock->cork) {
386 msg_tx = psock->cork;
387 } else {
388 msg_tx = &tmp;
389 sk_msg_init(msg_tx);
390 }
391
392 osize = msg_tx->sg.size;
393 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
394 if (err) {
395 if (err != -ENOSPC)
396 goto wait_for_memory;
397 enospc = true;
398 copy = msg_tx->sg.size - osize;
399 }
400
401 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
402 copy);
403 if (err < 0) {
404 sk_msg_trim(sk, msg_tx, osize);
405 goto out_err;
406 }
407
408 copied += copy;
409 if (psock->cork_bytes) {
410 if (size > psock->cork_bytes)
411 psock->cork_bytes = 0;
412 else
413 psock->cork_bytes -= size;
414 if (psock->cork_bytes && !enospc)
415 goto out_err;
416 /* All cork bytes are accounted, rerun the prog. */
417 psock->eval = __SK_NONE;
418 psock->cork_bytes = 0;
419 }
420
421 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
422 if (unlikely(err < 0))
423 goto out_err;
424 continue;
425wait_for_sndbuf:
426 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
427wait_for_memory:
428 err = sk_stream_wait_memory(sk, &timeo);
429 if (err) {
430 if (msg_tx && msg_tx != psock->cork)
431 sk_msg_free(sk, msg_tx);
432 goto out_err;
433 }
434 }
435out_err:
436 if (err < 0)
437 err = sk_stream_error(sk, msg->msg_flags, err);
438 release_sock(sk);
439 sk_psock_put(sk, psock);
440 return copied ? copied : err;
441}
442
443static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset,
444 size_t size, int flags)
445{
446 struct sk_msg tmp, *msg = NULL;
447 int err = 0, copied = 0;
448 struct sk_psock *psock;
449 bool enospc = false;
450
451 psock = sk_psock_get(sk);
452 if (unlikely(!psock))
453 return tcp_sendpage(sk, page, offset, size, flags);
454
455 lock_sock(sk);
456 if (psock->cork) {
457 msg = psock->cork;
458 } else {
459 msg = &tmp;
460 sk_msg_init(msg);
461 }
462
463 /* Catch case where ring is full and sendpage is stalled. */
464 if (unlikely(sk_msg_full(msg)))
465 goto out_err;
466
467 sk_msg_page_add(msg, page, size, offset);
468 sk_mem_charge(sk, size);
469 copied = size;
470 if (sk_msg_full(msg))
471 enospc = true;
472 if (psock->cork_bytes) {
473 if (size > psock->cork_bytes)
474 psock->cork_bytes = 0;
475 else
476 psock->cork_bytes -= size;
477 if (psock->cork_bytes && !enospc)
478 goto out_err;
479 /* All cork bytes are accounted, rerun the prog. */
480 psock->eval = __SK_NONE;
481 psock->cork_bytes = 0;
482 }
483
484 err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags);
485out_err:
486 release_sock(sk);
487 sk_psock_put(sk, psock);
488 return copied ? copied : err;
489}
490
491static void tcp_bpf_remove(struct sock *sk, struct sk_psock *psock)
492{
493 struct sk_psock_link *link;
494
495 sk_psock_cork_free(psock);
496 __sk_psock_purge_ingress_msg(psock);
497 while ((link = sk_psock_link_pop(psock))) {
498 sk_psock_unlink(sk, link);
499 sk_psock_free_link(link);
500 }
501}
502
503static void tcp_bpf_unhash(struct sock *sk)
504{
505 void (*saved_unhash)(struct sock *sk);
506 struct sk_psock *psock;
507
508 rcu_read_lock();
509 psock = sk_psock(sk);
510 if (unlikely(!psock)) {
511 rcu_read_unlock();
512 if (sk->sk_prot->unhash)
513 sk->sk_prot->unhash(sk);
514 return;
515 }
516
517 saved_unhash = psock->saved_unhash;
518 tcp_bpf_remove(sk, psock);
519 rcu_read_unlock();
520 saved_unhash(sk);
521}
522
523static void tcp_bpf_close(struct sock *sk, long timeout)
524{
525 void (*saved_close)(struct sock *sk, long timeout);
526 struct sk_psock *psock;
527
528 lock_sock(sk);
529 rcu_read_lock();
530 psock = sk_psock(sk);
531 if (unlikely(!psock)) {
532 rcu_read_unlock();
533 release_sock(sk);
534 return sk->sk_prot->close(sk, timeout);
535 }
536
537 saved_close = psock->saved_close;
538 tcp_bpf_remove(sk, psock);
539 rcu_read_unlock();
540 release_sock(sk);
541 saved_close(sk, timeout);
542}
543
544enum {
545 TCP_BPF_IPV4,
546 TCP_BPF_IPV6,
547 TCP_BPF_NUM_PROTS,
548};
549
550enum {
551 TCP_BPF_BASE,
552 TCP_BPF_TX,
553 TCP_BPF_NUM_CFGS,
554};
555
556static struct proto *tcpv6_prot_saved __read_mostly;
557static DEFINE_SPINLOCK(tcpv6_prot_lock);
558static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
559
560static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
561 struct proto *base)
562{
563 prot[TCP_BPF_BASE] = *base;
564 prot[TCP_BPF_BASE].unhash = tcp_bpf_unhash;
565 prot[TCP_BPF_BASE].close = tcp_bpf_close;
566 prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg;
567 prot[TCP_BPF_BASE].stream_memory_read = tcp_bpf_stream_read;
568
569 prot[TCP_BPF_TX] = prot[TCP_BPF_BASE];
570 prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg;
571 prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage;
572}
573
574static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
575{
576 if (sk->sk_family == AF_INET6 &&
577 unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
578 spin_lock_bh(&tcpv6_prot_lock);
579 if (likely(ops != tcpv6_prot_saved)) {
580 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
581 smp_store_release(&tcpv6_prot_saved, ops);
582 }
583 spin_unlock_bh(&tcpv6_prot_lock);
584 }
585}
586
587static int __init tcp_bpf_v4_build_proto(void)
588{
589 tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
590 return 0;
591}
592core_initcall(tcp_bpf_v4_build_proto);
593
594static void tcp_bpf_update_sk_prot(struct sock *sk, struct sk_psock *psock)
595{
596 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
597 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
598
599 sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config]);
600}
601
602static void tcp_bpf_reinit_sk_prot(struct sock *sk, struct sk_psock *psock)
603{
604 int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
605 int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE;
606
607 /* Reinit occurs when program types change e.g. TCP_BPF_TX is removed
608 * or added requiring sk_prot hook updates. We keep original saved
609 * hooks in this case.
610 */
611 sk->sk_prot = &tcp_bpf_prots[family][config];
612}
613
614static int tcp_bpf_assert_proto_ops(struct proto *ops)
615{
616 /* In order to avoid retpoline, we make assumptions when we call
617 * into ops if e.g. a psock is not present. Make sure they are
618 * indeed valid assumptions.
619 */
620 return ops->recvmsg == tcp_recvmsg &&
621 ops->sendmsg == tcp_sendmsg &&
622 ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP;
623}
624
625void tcp_bpf_reinit(struct sock *sk)
626{
627 struct sk_psock *psock;
628
629 sock_owned_by_me(sk);
630
631 rcu_read_lock();
632 psock = sk_psock(sk);
633 tcp_bpf_reinit_sk_prot(sk, psock);
634 rcu_read_unlock();
635}
636
637int tcp_bpf_init(struct sock *sk)
638{
639 struct proto *ops = READ_ONCE(sk->sk_prot);
640 struct sk_psock *psock;
641
642 sock_owned_by_me(sk);
643
644 rcu_read_lock();
645 psock = sk_psock(sk);
646 if (unlikely(!psock || psock->sk_proto ||
647 tcp_bpf_assert_proto_ops(ops))) {
648 rcu_read_unlock();
649 return -EINVAL;
650 }
651 tcp_bpf_check_v6_needs_rebuild(sk, ops);
652 tcp_bpf_update_sk_prot(sk, psock);
653 rcu_read_unlock();
654 return 0;
655}
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-10 10:29:57 -0400