net/ipv4/tcp_bpf.c

   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->sk_data_ready(sk);
 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 }