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