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TOMOYO Linux Cross Reference
Linux/net/ipv4/tcp_bpf.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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