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