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 #include <linux/util_macros.h>
  10
  11 #include <net/inet_common.h>
  12 #include <net/tls.h>
  13
  14 void tcp_eat_skb(struct sock *sk, struct sk_buff *skb)
  15 {
  16         struct tcp_sock *tcp;
  17         int copied;
  18
  19         if (!skb || !skb->len || !sk_is_tcp(sk))
  20                 return;
  21
  22         if (skb_bpf_strparser(skb))
  23                 return;
  24
  25         tcp = tcp_sk(sk);
  26         copied = tcp->copied_seq + skb->len;
  27         WRITE_ONCE(tcp->copied_seq, copied);
  28         tcp_rcv_space_adjust(sk);
  29         __tcp_cleanup_rbuf(sk, skb->len);
  30 }
  31
  32 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
  33                            struct sk_msg *msg, u32 apply_bytes)
  34 {
  35         bool apply = apply_bytes;
  36         struct scatterlist *sge;
  37         u32 size, copied = 0;
  38         struct sk_msg *tmp;
  39         int i, ret = 0;
  40
  41         tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL);
  42         if (unlikely(!tmp))
  43                 return -ENOMEM;
  44
  45         lock_sock(sk);
  46         tmp->sg.start = msg->sg.start;
  47         i = msg->sg.start;
  48         do {
  49                 sge = sk_msg_elem(msg, i);
  50                 size = (apply && apply_bytes < sge->length) ?
  51                         apply_bytes : sge->length;
  52                 if (!sk_wmem_schedule(sk, size)) {
  53                         if (!copied)
  54                                 ret = -ENOMEM;
  55                         break;
  56                 }
  57
  58                 sk_mem_charge(sk, size);
  59                 sk_msg_xfer(tmp, msg, i, size);
  60                 copied += size;
  61                 if (sge->length)
  62                         get_page(sk_msg_page(tmp, i));
  63                 sk_msg_iter_var_next(i);
  64                 tmp->sg.end = i;
  65                 if (apply) {
  66                         apply_bytes -= size;
  67                         if (!apply_bytes) {
  68                                 if (sge->length)
  69                                         sk_msg_iter_var_prev(i);
  70                                 break;
  71                         }
  72                 }
  73         } while (i != msg->sg.end);
  74
  75         if (!ret) {
  76                 msg->sg.start = i;
  77                 sk_psock_queue_msg(psock, tmp);
  78                 sk_psock_data_ready(sk, psock);
  79         } else {
  80                 sk_msg_free(sk, tmp);
  81                 kfree(tmp);
  82         }
  83
  84         release_sock(sk);
  85         return ret;
  86 }
  87
  88 static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
  89                         int flags, bool uncharge)
  90 {
  91         struct msghdr msghdr = {};
  92         bool apply = apply_bytes;
  93         struct scatterlist *sge;
  94         struct page *page;
  95         int size, ret = 0;
  96         u32 off;
  97
  98         while (1) {
  99                 struct bio_vec bvec;
 100                 bool has_tx_ulp;
 101
 102                 sge = sk_msg_elem(msg, msg->sg.start);
 103                 size = (apply && apply_bytes < sge->length) ?
 104                         apply_bytes : sge->length;
 105                 off  = sge->offset;
 106                 page = sg_page(sge);
 107
 108                 tcp_rate_check_app_limited(sk);
 109 retry:
 110                 msghdr.msg_flags = flags | MSG_SPLICE_PAGES;
 111                 has_tx_ulp = tls_sw_has_ctx_tx(sk);
 112                 if (has_tx_ulp)
 113                         msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY;
 114
 115                 if (size < sge->length && msg->sg.start != msg->sg.end)
 116                         msghdr.msg_flags |= MSG_MORE;
 117
 118                 bvec_set_page(&bvec, page, size, off);
 119                 iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size);
 120                 ret = tcp_sendmsg_locked(sk, &msghdr, size);
 121                 if (ret <= 0)
 122                         return ret;
 123
 124                 if (apply)
 125                         apply_bytes -= ret;
 126                 msg->sg.size -= ret;
 127                 sge->offset += ret;
 128                 sge->length -= ret;
 129                 if (uncharge)
 130                         sk_mem_uncharge(sk, ret);
 131                 if (ret != size) {
 132                         size -= ret;
 133                         off  += ret;
 134                         goto retry;
 135                 }
 136                 if (!sge->length) {
 137                         put_page(page);
 138                         sk_msg_iter_next(msg, start);
 139                         sg_init_table(sge, 1);
 140                         if (msg->sg.start == msg->sg.end)
 141                                 break;
 142                 }
 143                 if (apply && !apply_bytes)
 144                         break;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
 151                                u32 apply_bytes, int flags, bool uncharge)
 152 {
 153         int ret;
 154
 155         lock_sock(sk);
 156         ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
 157         release_sock(sk);
 158         return ret;
 159 }
 160
 161 int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress,
 162                           struct sk_msg *msg, u32 bytes, int flags)
 163 {
 164         struct sk_psock *psock = sk_psock_get(sk);
 165         int ret;
 166
 167         if (unlikely(!psock))
 168                 return -EPIPE;
 169
 170         ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes) :
 171                         tcp_bpf_push_locked(sk, msg, bytes, flags, false);
 172         sk_psock_put(sk, psock);
 173         return ret;
 174 }
 175 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
 176
 177 #ifdef CONFIG_BPF_SYSCALL
 178 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
 179                              long timeo)
 180 {
 181         DEFINE_WAIT_FUNC(wait, woken_wake_function);
 182         int ret = 0;
 183
 184         if (sk->sk_shutdown & RCV_SHUTDOWN)
 185                 return 1;
 186
 187         if (!timeo)
 188                 return ret;
 189
 190         add_wait_queue(sk_sleep(sk), &wait);
 191         sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 192         ret = sk_wait_event(sk, &timeo,
 193                             !list_empty(&psock->ingress_msg) ||
 194                             !skb_queue_empty_lockless(&sk->sk_receive_queue), &wait);
 195         sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 196         remove_wait_queue(sk_sleep(sk), &wait);
 197         return ret;
 198 }
 199
 200 static bool is_next_msg_fin(struct sk_psock *psock)
 201 {
 202         struct scatterlist *sge;
 203         struct sk_msg *msg_rx;
 204         int i;
 205
 206         msg_rx = sk_psock_peek_msg(psock);
 207         i = msg_rx->sg.start;
 208         sge = sk_msg_elem(msg_rx, i);
 209         if (!sge->length) {
 210                 struct sk_buff *skb = msg_rx->skb;
 211
 212                 if (skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 213                         return true;
 214         }
 215         return false;
 216 }
 217
 218 static int tcp_bpf_recvmsg_parser(struct sock *sk,
 219                                   struct msghdr *msg,
 220                                   size_t len,
 221                                   int flags,
 222                                   int *addr_len)
 223 {
 224         int peek = flags & MSG_PEEK;
 225         struct sk_psock *psock;
 226         struct tcp_sock *tcp;
 227         int copied = 0;
 228         u32 seq;
 229
 230         if (unlikely(flags & MSG_ERRQUEUE))
 231                 return inet_recv_error(sk, msg, len, addr_len);
 232
 233         if (!len)
 234                 return 0;
 235
 236         psock = sk_psock_get(sk);
 237         if (unlikely(!psock))
 238                 return tcp_recvmsg(sk, msg, len, flags, addr_len);
 239
 240         lock_sock(sk);
 241         tcp = tcp_sk(sk);
 242         seq = tcp->copied_seq;
 243         /* We may have received data on the sk_receive_queue pre-accept and
 244          * then we can not use read_skb in this context because we haven't
 245          * assigned a sk_socket yet so have no link to the ops. The work-around
 246          * is to check the sk_receive_queue and in these cases read skbs off
 247          * queue again. The read_skb hook is not running at this point because
 248          * of lock_sock so we avoid having multiple runners in read_skb.
 249          */
 250         if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
 251                 tcp_data_ready(sk);
 252                 /* This handles the ENOMEM errors if we both receive data
 253                  * pre accept and are already under memory pressure. At least
 254                  * let user know to retry.
 255                  */
 256                 if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) {
 257                         copied = -EAGAIN;
 258                         goto out;
 259                 }
 260         }
 261
 262 msg_bytes_ready:
 263         copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
 264         /* The typical case for EFAULT is the socket was gracefully
 265          * shutdown with a FIN pkt. So check here the other case is
 266          * some error on copy_page_to_iter which would be unexpected.
 267          * On fin return correct return code to zero.
 268          */
 269         if (copied == -EFAULT) {
 270                 bool is_fin = is_next_msg_fin(psock);
 271
 272                 if (is_fin) {
 273                         copied = 0;
 274                         seq++;
 275                         goto out;
 276                 }
 277         }
 278         seq += copied;
 279         if (!copied) {
 280                 long timeo;
 281                 int data;
 282
 283                 if (sock_flag(sk, SOCK_DONE))
 284                         goto out;
 285
 286                 if (sk->sk_err) {
 287                         copied = sock_error(sk);
 288                         goto out;
 289                 }
 290
 291                 if (sk->sk_shutdown & RCV_SHUTDOWN)
 292                         goto out;
 293
 294                 if (sk->sk_state == TCP_CLOSE) {
 295                         copied = -ENOTCONN;
 296                         goto out;
 297                 }
 298
 299                 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 300                 if (!timeo) {
 301                         copied = -EAGAIN;
 302                         goto out;
 303                 }
 304
 305                 if (signal_pending(current)) {
 306                         copied = sock_intr_errno(timeo);
 307                         goto out;
 308                 }
 309
 310                 data = tcp_msg_wait_data(sk, psock, timeo);
 311                 if (data < 0) {
 312                         copied = data;
 313                         goto unlock;
 314                 }
 315                 if (data && !sk_psock_queue_empty(psock))
 316                         goto msg_bytes_ready;
 317                 copied = -EAGAIN;
 318         }
 319 out:
 320         if (!peek)
 321                 WRITE_ONCE(tcp->copied_seq, seq);
 322         tcp_rcv_space_adjust(sk);
 323         if (copied > 0)
 324                 __tcp_cleanup_rbuf(sk, copied);
 325
 326 unlock:
 327         release_sock(sk);
 328         sk_psock_put(sk, psock);
 329         return copied;
 330 }
 331
 332 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 333                            int flags, int *addr_len)
 334 {
 335         struct sk_psock *psock;
 336         int copied, ret;
 337
 338         if (unlikely(flags & MSG_ERRQUEUE))
 339                 return inet_recv_error(sk, msg, len, addr_len);
 340
 341         if (!len)
 342                 return 0;
 343
 344         psock = sk_psock_get(sk);
 345         if (unlikely(!psock))
 346                 return tcp_recvmsg(sk, msg, len, flags, addr_len);
 347         if (!skb_queue_empty(&sk->sk_receive_queue) &&
 348             sk_psock_queue_empty(psock)) {
 349                 sk_psock_put(sk, psock);
 350                 return tcp_recvmsg(sk, msg, len, flags, addr_len);
 351         }
 352         lock_sock(sk);
 353 msg_bytes_ready:
 354         copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
 355         if (!copied) {
 356                 long timeo;
 357                 int data;
 358
 359                 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 360                 data = tcp_msg_wait_data(sk, psock, timeo);
 361                 if (data < 0) {
 362                         ret = data;
 363                         goto unlock;
 364                 }
 365                 if (data) {
 366                         if (!sk_psock_queue_empty(psock))
 367                                 goto msg_bytes_ready;
 368                         release_sock(sk);
 369                         sk_psock_put(sk, psock);
 370                         return tcp_recvmsg(sk, msg, len, flags, addr_len);
 371                 }
 372                 copied = -EAGAIN;
 373         }
 374         ret = copied;
 375
 376 unlock:
 377         release_sock(sk);
 378         sk_psock_put(sk, psock);
 379         return ret;
 380 }
 381
 382 static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
 383                                 struct sk_msg *msg, int *copied, int flags)
 384 {
 385         bool cork = false, enospc = sk_msg_full(msg), redir_ingress;
 386         struct sock *sk_redir;
 387         u32 tosend, origsize, sent, delta = 0;
 388         u32 eval;
 389         int ret;
 390
 391 more_data:
 392         if (psock->eval == __SK_NONE) {
 393                 /* Track delta in msg size to add/subtract it on SK_DROP from
 394                  * returned to user copied size. This ensures user doesn't
 395                  * get a positive return code with msg_cut_data and SK_DROP
 396                  * verdict.
 397                  */
 398                 delta = msg->sg.size;
 399                 psock->eval = sk_psock_msg_verdict(sk, psock, msg);
 400                 delta -= msg->sg.size;
 401         }
 402
 403         if (msg->cork_bytes &&
 404             msg->cork_bytes > msg->sg.size && !enospc) {
 405                 psock->cork_bytes = msg->cork_bytes - msg->sg.size;
 406                 if (!psock->cork) {
 407                         psock->cork = kzalloc(sizeof(*psock->cork),
 408                                               GFP_ATOMIC | __GFP_NOWARN);
 409                         if (!psock->cork)
 410                                 return -ENOMEM;
 411                 }
 412                 memcpy(psock->cork, msg, sizeof(*msg));
 413                 return 0;
 414         }
 415
 416         tosend = msg->sg.size;
 417         if (psock->apply_bytes && psock->apply_bytes < tosend)
 418                 tosend = psock->apply_bytes;
 419         eval = __SK_NONE;
 420
 421         switch (psock->eval) {
 422         case __SK_PASS:
 423                 ret = tcp_bpf_push(sk, msg, tosend, flags, true);
 424                 if (unlikely(ret)) {
 425                         *copied -= sk_msg_free(sk, msg);
 426                         break;
 427                 }
 428                 sk_msg_apply_bytes(psock, tosend);
 429                 break;
 430         case __SK_REDIRECT:
 431                 redir_ingress = psock->redir_ingress;
 432                 sk_redir = psock->sk_redir;
 433                 sk_msg_apply_bytes(psock, tosend);
 434                 if (!psock->apply_bytes) {
 435                         /* Clean up before releasing the sock lock. */
 436                         eval = psock->eval;
 437                         psock->eval = __SK_NONE;
 438                         psock->sk_redir = NULL;
 439                 }
 440                 if (psock->cork) {
 441                         cork = true;
 442                         psock->cork = NULL;
 443                 }
 444                 sk_msg_return(sk, msg, tosend);
 445                 release_sock(sk);
 446
 447                 origsize = msg->sg.size;
 448                 ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress,
 449                                             msg, tosend, flags);
 450                 sent = origsize - msg->sg.size;
 451
 452                 if (eval == __SK_REDIRECT)
 453                         sock_put(sk_redir);
 454
 455                 lock_sock(sk);
 456                 if (unlikely(ret < 0)) {
 457                         int free = sk_msg_free_nocharge(sk, msg);
 458
 459                         if (!cork)
 460                                 *copied -= free;
 461                 }
 462                 if (cork) {
 463                         sk_msg_free(sk, msg);
 464                         kfree(msg);
 465                         msg = NULL;
 466                         ret = 0;
 467                 }
 468                 break;
 469         case __SK_DROP:
 470         default:
 471                 sk_msg_free_partial(sk, msg, tosend);
 472                 sk_msg_apply_bytes(psock, tosend);
 473                 *copied -= (tosend + delta);
 474                 return -EACCES;
 475         }
 476
 477         if (likely(!ret)) {
 478                 if (!psock->apply_bytes) {
 479                         psock->eval =  __SK_NONE;
 480                         if (psock->sk_redir) {
 481                                 sock_put(psock->sk_redir);
 482                                 psock->sk_redir = NULL;
 483                         }
 484                 }
 485                 if (msg &&
 486                     msg->sg.data[msg->sg.start].page_link &&
 487                     msg->sg.data[msg->sg.start].length) {
 488                         if (eval == __SK_REDIRECT)
 489                                 sk_mem_charge(sk, tosend - sent);
 490                         goto more_data;
 491                 }
 492         }
 493         return ret;
 494 }
 495
 496 static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 497 {
 498         struct sk_msg tmp, *msg_tx = NULL;
 499         int copied = 0, err = 0;
 500         struct sk_psock *psock;
 501         long timeo;
 502         int flags;
 503
 504         /* Don't let internal flags through */
 505         flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED);
 506         flags |= MSG_NO_SHARED_FRAGS;
 507
 508         psock = sk_psock_get(sk);
 509         if (unlikely(!psock))
 510                 return tcp_sendmsg(sk, msg, size);
 511
 512         lock_sock(sk);
 513         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 514         while (msg_data_left(msg)) {
 515                 bool enospc = false;
 516                 u32 copy, osize;
 517
 518                 if (sk->sk_err) {
 519                         err = -sk->sk_err;
 520                         goto out_err;
 521                 }
 522
 523                 copy = msg_data_left(msg);
 524                 if (!sk_stream_memory_free(sk))
 525                         goto wait_for_sndbuf;
 526                 if (psock->cork) {
 527                         msg_tx = psock->cork;
 528                 } else {
 529                         msg_tx = &tmp;
 530                         sk_msg_init(msg_tx);
 531                 }
 532
 533                 osize = msg_tx->sg.size;
 534                 err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
 535                 if (err) {
 536                         if (err != -ENOSPC)
 537                                 goto wait_for_memory;
 538                         enospc = true;
 539                         copy = msg_tx->sg.size - osize;
 540                 }
 541
 542                 err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
 543                                                copy);
 544                 if (err < 0) {
 545                         sk_msg_trim(sk, msg_tx, osize);
 546                         goto out_err;
 547                 }
 548
 549                 copied += copy;
 550                 if (psock->cork_bytes) {
 551                         if (size > psock->cork_bytes)
 552                                 psock->cork_bytes = 0;
 553                         else
 554                                 psock->cork_bytes -= size;
 555                         if (psock->cork_bytes && !enospc)
 556                                 goto out_err;
 557                         /* All cork bytes are accounted, rerun the prog. */
 558                         psock->eval = __SK_NONE;
 559                         psock->cork_bytes = 0;
 560                 }
 561
 562                 err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
 563                 if (unlikely(err < 0))
 564                         goto out_err;
 565                 continue;
 566 wait_for_sndbuf:
 567                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 568 wait_for_memory:
 569                 err = sk_stream_wait_memory(sk, &timeo);
 570                 if (err) {
 571                         if (msg_tx && msg_tx != psock->cork)
 572                                 sk_msg_free(sk, msg_tx);
 573                         goto out_err;
 574                 }
 575         }
 576 out_err:
 577         if (err < 0)
 578                 err = sk_stream_error(sk, msg->msg_flags, err);
 579         release_sock(sk);
 580         sk_psock_put(sk, psock);
 581         return copied > 0 ? copied : err;
 582 }
 583
 584 enum {
 585         TCP_BPF_IPV4,
 586         TCP_BPF_IPV6,
 587         TCP_BPF_NUM_PROTS,
 588 };
 589
 590 enum {
 591         TCP_BPF_BASE,
 592         TCP_BPF_TX,
 593         TCP_BPF_RX,
 594         TCP_BPF_TXRX,
 595         TCP_BPF_NUM_CFGS,
 596 };
 597
 598 static struct proto *tcpv6_prot_saved __read_mostly;
 599 static DEFINE_SPINLOCK(tcpv6_prot_lock);
 600 static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
 601
 602 static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
 603                                    struct proto *base)
 604 {
 605         prot[TCP_BPF_BASE]                      = *base;
 606         prot[TCP_BPF_BASE].destroy              = sock_map_destroy;
 607         prot[TCP_BPF_BASE].close                = sock_map_close;
 608         prot[TCP_BPF_BASE].recvmsg              = tcp_bpf_recvmsg;
 609         prot[TCP_BPF_BASE].sock_is_readable     = sk_msg_is_readable;
 610
 611         prot[TCP_BPF_TX]                        = prot[TCP_BPF_BASE];
 612         prot[TCP_BPF_TX].sendmsg                = tcp_bpf_sendmsg;
 613
 614         prot[TCP_BPF_RX]                        = prot[TCP_BPF_BASE];
 615         prot[TCP_BPF_RX].recvmsg                = tcp_bpf_recvmsg_parser;
 616
 617         prot[TCP_BPF_TXRX]                      = prot[TCP_BPF_TX];
 618         prot[TCP_BPF_TXRX].recvmsg              = tcp_bpf_recvmsg_parser;
 619 }
 620
 621 static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops)
 622 {
 623         if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
 624                 spin_lock_bh(&tcpv6_prot_lock);
 625                 if (likely(ops != tcpv6_prot_saved)) {
 626                         tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
 627                         smp_store_release(&tcpv6_prot_saved, ops);
 628                 }
 629                 spin_unlock_bh(&tcpv6_prot_lock);
 630         }
 631 }
 632
 633 static int __init tcp_bpf_v4_build_proto(void)
 634 {
 635         tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
 636         return 0;
 637 }
 638 late_initcall(tcp_bpf_v4_build_proto);
 639
 640 static int tcp_bpf_assert_proto_ops(struct proto *ops)
 641 {
 642         /* In order to avoid retpoline, we make assumptions when we call
 643          * into ops if e.g. a psock is not present. Make sure they are
 644          * indeed valid assumptions.
 645          */
 646         return ops->recvmsg  == tcp_recvmsg &&
 647                ops->sendmsg  == tcp_sendmsg ? 0 : -ENOTSUPP;
 648 }
 649
 650 int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
 651 {
 652         int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
 653         int config = psock->progs.msg_parser   ? TCP_BPF_TX   : TCP_BPF_BASE;
 654
 655         if (psock->progs.stream_verdict || psock->progs.skb_verdict) {
 656                 config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX;
 657         }
 658
 659         if (restore) {
 660                 if (inet_csk_has_ulp(sk)) {
 661                         /* TLS does not have an unhash proto in SW cases,
 662                          * but we need to ensure we stop using the sock_map
 663                          * unhash routine because the associated psock is being
 664                          * removed. So use the original unhash handler.
 665                          */
 666                         WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash);
 667                         tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 668                 } else {
 669                         sk->sk_write_space = psock->saved_write_space;
 670                         /* Pairs with lockless read in sk_clone_lock() */
 671                         sock_replace_proto(sk, psock->sk_proto);
 672                 }
 673                 return 0;
 674         }
 675
 676         if (sk->sk_family == AF_INET6) {
 677                 if (tcp_bpf_assert_proto_ops(psock->sk_proto))
 678                         return -EINVAL;
 679
 680                 tcp_bpf_check_v6_needs_rebuild(psock->sk_proto);
 681         }
 682
 683         /* Pairs with lockless read in sk_clone_lock() */
 684         sock_replace_proto(sk, &tcp_bpf_prots[family][config]);
 685         return 0;
 686 }
 687 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto);
 688
 689 /* If a child got cloned from a listening socket that had tcp_bpf
 690  * protocol callbacks installed, we need to restore the callbacks to
 691  * the default ones because the child does not inherit the psock state
 692  * that tcp_bpf callbacks expect.
 693  */
 694 void tcp_bpf_clone(const struct sock *sk, struct sock *newsk)
 695 {
 696         struct proto *prot = newsk->sk_prot;
 697
 698         if (is_insidevar(prot, tcp_bpf_prots))
 699                 newsk->sk_prot = sk->sk_prot_creator;
 700 }
 701 #endif /* CONFIG_BPF_SYSCALL */