net/core/skmsg.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/skbuff.h>
   6 #include <linux/scatterlist.h>
   7
   8 #include <net/sock.h>
   9 #include <net/tcp.h>
  10 #include <net/tls.h>
  11
  12 static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
  13 {
  14         if (msg->sg.end > msg->sg.start &&
  15             elem_first_coalesce < msg->sg.end)
  16                 return true;
  17
  18         if (msg->sg.end < msg->sg.start &&
  19             (elem_first_coalesce > msg->sg.start ||
  20              elem_first_coalesce < msg->sg.end))
  21                 return true;
  22
  23         return false;
  24 }
  25
  26 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
  27                  int elem_first_coalesce)
  28 {
  29         struct page_frag *pfrag = sk_page_frag(sk);
  30         int ret = 0;
  31
  32         len -= msg->sg.size;
  33         while (len > 0) {
  34                 struct scatterlist *sge;
  35                 u32 orig_offset;
  36                 int use, i;
  37
  38                 if (!sk_page_frag_refill(sk, pfrag))
  39                         return -ENOMEM;
  40
  41                 orig_offset = pfrag->offset;
  42                 use = min_t(int, len, pfrag->size - orig_offset);
  43                 if (!sk_wmem_schedule(sk, use))
  44                         return -ENOMEM;
  45
  46                 i = msg->sg.end;
  47                 sk_msg_iter_var_prev(i);
  48                 sge = &msg->sg.data[i];
  49
  50                 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
  51                     sg_page(sge) == pfrag->page &&
  52                     sge->offset + sge->length == orig_offset) {
  53                         sge->length += use;
  54                 } else {
  55                         if (sk_msg_full(msg)) {
  56                                 ret = -ENOSPC;
  57                                 break;
  58                         }
  59
  60                         sge = &msg->sg.data[msg->sg.end];
  61                         sg_unmark_end(sge);
  62                         sg_set_page(sge, pfrag->page, use, orig_offset);
  63                         get_page(pfrag->page);
  64                         sk_msg_iter_next(msg, end);
  65                 }
  66
  67                 sk_mem_charge(sk, use);
  68                 msg->sg.size += use;
  69                 pfrag->offset += use;
  70                 len -= use;
  71         }
  72
  73         return ret;
  74 }
  75 EXPORT_SYMBOL_GPL(sk_msg_alloc);
  76
  77 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
  78                  u32 off, u32 len)
  79 {
  80         int i = src->sg.start;
  81         struct scatterlist *sge = sk_msg_elem(src, i);
  82         struct scatterlist *sgd = NULL;
  83         u32 sge_len, sge_off;
  84
  85         while (off) {
  86                 if (sge->length > off)
  87                         break;
  88                 off -= sge->length;
  89                 sk_msg_iter_var_next(i);
  90                 if (i == src->sg.end && off)
  91                         return -ENOSPC;
  92                 sge = sk_msg_elem(src, i);
  93         }
  94
  95         while (len) {
  96                 sge_len = sge->length - off;
  97                 if (sge_len > len)
  98                         sge_len = len;
  99
 100                 if (dst->sg.end)
 101                         sgd = sk_msg_elem(dst, dst->sg.end - 1);
 102
 103                 if (sgd &&
 104                     (sg_page(sge) == sg_page(sgd)) &&
 105                     (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
 106                         sgd->length += sge_len;
 107                         dst->sg.size += sge_len;
 108                 } else if (!sk_msg_full(dst)) {
 109                         sge_off = sge->offset + off;
 110                         sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
 111                 } else {
 112                         return -ENOSPC;
 113                 }
 114
 115                 off = 0;
 116                 len -= sge_len;
 117                 sk_mem_charge(sk, sge_len);
 118                 sk_msg_iter_var_next(i);
 119                 if (i == src->sg.end && len)
 120                         return -ENOSPC;
 121                 sge = sk_msg_elem(src, i);
 122         }
 123
 124         return 0;
 125 }
 126 EXPORT_SYMBOL_GPL(sk_msg_clone);
 127
 128 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
 129 {
 130         int i = msg->sg.start;
 131
 132         do {
 133                 struct scatterlist *sge = sk_msg_elem(msg, i);
 134
 135                 if (bytes < sge->length) {
 136                         sge->length -= bytes;
 137                         sge->offset += bytes;
 138                         sk_mem_uncharge(sk, bytes);
 139                         break;
 140                 }
 141
 142                 sk_mem_uncharge(sk, sge->length);
 143                 bytes -= sge->length;
 144                 sge->length = 0;
 145                 sge->offset = 0;
 146                 sk_msg_iter_var_next(i);
 147         } while (bytes && i != msg->sg.end);
 148         msg->sg.start = i;
 149 }
 150 EXPORT_SYMBOL_GPL(sk_msg_return_zero);
 151
 152 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
 153 {
 154         int i = msg->sg.start;
 155
 156         do {
 157                 struct scatterlist *sge = &msg->sg.data[i];
 158                 int uncharge = (bytes < sge->length) ? bytes : sge->length;
 159
 160                 sk_mem_uncharge(sk, uncharge);
 161                 bytes -= uncharge;
 162                 sk_msg_iter_var_next(i);
 163         } while (i != msg->sg.end);
 164 }
 165 EXPORT_SYMBOL_GPL(sk_msg_return);
 166
 167 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
 168                             bool charge)
 169 {
 170         struct scatterlist *sge = sk_msg_elem(msg, i);
 171         u32 len = sge->length;
 172
 173         if (charge)
 174                 sk_mem_uncharge(sk, len);
 175         if (!msg->skb)
 176                 put_page(sg_page(sge));
 177         memset(sge, 0, sizeof(*sge));
 178         return len;
 179 }
 180
 181 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
 182                          bool charge)
 183 {
 184         struct scatterlist *sge = sk_msg_elem(msg, i);
 185         int freed = 0;
 186
 187         while (msg->sg.size) {
 188                 msg->sg.size -= sge->length;
 189                 freed += sk_msg_free_elem(sk, msg, i, charge);
 190                 sk_msg_iter_var_next(i);
 191                 sk_msg_check_to_free(msg, i, msg->sg.size);
 192                 sge = sk_msg_elem(msg, i);
 193         }
 194         consume_skb(msg->skb);
 195         sk_msg_init(msg);
 196         return freed;
 197 }
 198
 199 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
 200 {
 201         return __sk_msg_free(sk, msg, msg->sg.start, false);
 202 }
 203 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
 204
 205 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
 206 {
 207         return __sk_msg_free(sk, msg, msg->sg.start, true);
 208 }
 209 EXPORT_SYMBOL_GPL(sk_msg_free);
 210
 211 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
 212                                   u32 bytes, bool charge)
 213 {
 214         struct scatterlist *sge;
 215         u32 i = msg->sg.start;
 216
 217         while (bytes) {
 218                 sge = sk_msg_elem(msg, i);
 219                 if (!sge->length)
 220                         break;
 221                 if (bytes < sge->length) {
 222                         if (charge)
 223                                 sk_mem_uncharge(sk, bytes);
 224                         sge->length -= bytes;
 225                         sge->offset += bytes;
 226                         msg->sg.size -= bytes;
 227                         break;
 228                 }
 229
 230                 msg->sg.size -= sge->length;
 231                 bytes -= sge->length;
 232                 sk_msg_free_elem(sk, msg, i, charge);
 233                 sk_msg_iter_var_next(i);
 234                 sk_msg_check_to_free(msg, i, bytes);
 235         }
 236         msg->sg.start = i;
 237 }
 238
 239 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
 240 {
 241         __sk_msg_free_partial(sk, msg, bytes, true);
 242 }
 243 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
 244
 245 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 246                                   u32 bytes)
 247 {
 248         __sk_msg_free_partial(sk, msg, bytes, false);
 249 }
 250
 251 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
 252 {
 253         int trim = msg->sg.size - len;
 254         u32 i = msg->sg.end;
 255
 256         if (trim <= 0) {
 257                 WARN_ON(trim < 0);
 258                 return;
 259         }
 260
 261         sk_msg_iter_var_prev(i);
 262         msg->sg.size = len;
 263         while (msg->sg.data[i].length &&
 264                trim >= msg->sg.data[i].length) {
 265                 trim -= msg->sg.data[i].length;
 266                 sk_msg_free_elem(sk, msg, i, true);
 267                 sk_msg_iter_var_prev(i);
 268                 if (!trim)
 269                         goto out;
 270         }
 271
 272         msg->sg.data[i].length -= trim;
 273         sk_mem_uncharge(sk, trim);
 274         /* Adjust copybreak if it falls into the trimmed part of last buf */
 275         if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
 276                 msg->sg.copybreak = msg->sg.data[i].length;
 277 out:
 278         sk_msg_iter_var_next(i);
 279         msg->sg.end = i;
 280
 281         /* If we trim data a full sg elem before curr pointer update
 282          * copybreak and current so that any future copy operations
 283          * start at new copy location.
 284          * However trimed data that has not yet been used in a copy op
 285          * does not require an update.
 286          */
 287         if (!msg->sg.size) {
 288                 msg->sg.curr = msg->sg.start;
 289                 msg->sg.copybreak = 0;
 290         } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
 291                    sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
 292                 sk_msg_iter_var_prev(i);
 293                 msg->sg.curr = i;
 294                 msg->sg.copybreak = msg->sg.data[i].length;
 295         }
 296 }
 297 EXPORT_SYMBOL_GPL(sk_msg_trim);
 298
 299 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 300                               struct sk_msg *msg, u32 bytes)
 301 {
 302         int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
 303         const int to_max_pages = MAX_MSG_FRAGS;
 304         struct page *pages[MAX_MSG_FRAGS];
 305         ssize_t orig, copied, use, offset;
 306
 307         orig = msg->sg.size;
 308         while (bytes > 0) {
 309                 i = 0;
 310                 maxpages = to_max_pages - num_elems;
 311                 if (maxpages == 0) {
 312                         ret = -EFAULT;
 313                         goto out;
 314                 }
 315
 316                 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
 317                                             &offset);
 318                 if (copied <= 0) {
 319                         ret = -EFAULT;
 320                         goto out;
 321                 }
 322
 323                 iov_iter_advance(from, copied);
 324                 bytes -= copied;
 325                 msg->sg.size += copied;
 326
 327                 while (copied) {
 328                         use = min_t(int, copied, PAGE_SIZE - offset);
 329                         sg_set_page(&msg->sg.data[msg->sg.end],
 330                                     pages[i], use, offset);
 331                         sg_unmark_end(&msg->sg.data[msg->sg.end]);
 332                         sk_mem_charge(sk, use);
 333
 334                         offset = 0;
 335                         copied -= use;
 336                         sk_msg_iter_next(msg, end);
 337                         num_elems++;
 338                         i++;
 339                 }
 340                 /* When zerocopy is mixed with sk_msg_*copy* operations we
 341                  * may have a copybreak set in this case clear and prefer
 342                  * zerocopy remainder when possible.
 343                  */
 344                 msg->sg.copybreak = 0;
 345                 msg->sg.curr = msg->sg.end;
 346         }
 347 out:
 348         /* Revert iov_iter updates, msg will need to use 'trim' later if it
 349          * also needs to be cleared.
 350          */
 351         if (ret)
 352                 iov_iter_revert(from, msg->sg.size - orig);
 353         return ret;
 354 }
 355 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
 356
 357 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 358                              struct sk_msg *msg, u32 bytes)
 359 {
 360         int ret = -ENOSPC, i = msg->sg.curr;
 361         struct scatterlist *sge;
 362         u32 copy, buf_size;
 363         void *to;
 364
 365         do {
 366                 sge = sk_msg_elem(msg, i);
 367                 /* This is possible if a trim operation shrunk the buffer */
 368                 if (msg->sg.copybreak >= sge->length) {
 369                         msg->sg.copybreak = 0;
 370                         sk_msg_iter_var_next(i);
 371                         if (i == msg->sg.end)
 372                                 break;
 373                         sge = sk_msg_elem(msg, i);
 374                 }
 375
 376                 buf_size = sge->length - msg->sg.copybreak;
 377                 copy = (buf_size > bytes) ? bytes : buf_size;
 378                 to = sg_virt(sge) + msg->sg.copybreak;
 379                 msg->sg.copybreak += copy;
 380                 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
 381                         ret = copy_from_iter_nocache(to, copy, from);
 382                 else
 383                         ret = copy_from_iter(to, copy, from);
 384                 if (ret != copy) {
 385                         ret = -EFAULT;
 386                         goto out;
 387                 }
 388                 bytes -= copy;
 389                 if (!bytes)
 390                         break;
 391                 msg->sg.copybreak = 0;
 392                 sk_msg_iter_var_next(i);
 393         } while (i != msg->sg.end);
 394 out:
 395         msg->sg.curr = i;
 396         return ret;
 397 }
 398 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
 399
 400 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 401 {
 402         struct sock *sk = psock->sk;
 403         int copied = 0, num_sge;
 404         struct sk_msg *msg;
 405
 406         msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
 407         if (unlikely(!msg))
 408                 return -EAGAIN;
 409         if (!sk_rmem_schedule(sk, skb, skb->len)) {
 410                 kfree(msg);
 411                 return -EAGAIN;
 412         }
 413
 414         sk_msg_init(msg);
 415         num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
 416         if (unlikely(num_sge < 0)) {
 417                 kfree(msg);
 418                 return num_sge;
 419         }
 420
 421         sk_mem_charge(sk, skb->len);
 422         copied = skb->len;
 423         msg->sg.start = 0;
 424         msg->sg.size = copied;
 425         msg->sg.end = num_sge;
 426         msg->skb = skb;
 427
 428         sk_psock_queue_msg(psock, msg);
 429         sk_psock_data_ready(sk, psock);
 430         return copied;
 431 }
 432
 433 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 434                                u32 off, u32 len, bool ingress)
 435 {
 436         if (ingress)
 437                 return sk_psock_skb_ingress(psock, skb);
 438         else
 439                 return skb_send_sock_locked(psock->sk, skb, off, len);
 440 }
 441
 442 static void sk_psock_backlog(struct work_struct *work)
 443 {
 444         struct sk_psock *psock = container_of(work, struct sk_psock, work);
 445         struct sk_psock_work_state *state = &psock->work_state;
 446         struct sk_buff *skb;
 447         bool ingress;
 448         u32 len, off;
 449         int ret;
 450
 451         /* Lock sock to avoid losing sk_socket during loop. */
 452         lock_sock(psock->sk);
 453         if (state->skb) {
 454                 skb = state->skb;
 455                 len = state->len;
 456                 off = state->off;
 457                 state->skb = NULL;
 458                 goto start;
 459         }
 460
 461         while ((skb = skb_dequeue(&psock->ingress_skb))) {
 462                 len = skb->len;
 463                 off = 0;
 464 start:
 465                 ingress = tcp_skb_bpf_ingress(skb);
 466                 do {
 467                         ret = -EIO;
 468                         if (likely(psock->sk->sk_socket))
 469                                 ret = sk_psock_handle_skb(psock, skb, off,
 470                                                           len, ingress);
 471                         if (ret <= 0) {
 472                                 if (ret == -EAGAIN) {
 473                                         state->skb = skb;
 474                                         state->len = len;
 475                                         state->off = off;
 476                                         goto end;
 477                                 }
 478                                 /* Hard errors break pipe and stop xmit. */
 479                                 sk_psock_report_error(psock, ret ? -ret : EPIPE);
 480                                 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 481                                 kfree_skb(skb);
 482                                 goto end;
 483                         }
 484                         off += ret;
 485                         len -= ret;
 486                 } while (len);
 487
 488                 if (!ingress)
 489                         kfree_skb(skb);
 490         }
 491 end:
 492         release_sock(psock->sk);
 493 }
 494
 495 struct sk_psock *sk_psock_init(struct sock *sk, int node)
 496 {
 497         struct sk_psock *psock = kzalloc_node(sizeof(*psock),
 498                                               GFP_ATOMIC | __GFP_NOWARN,
 499                                               node);
 500         if (!psock)
 501                 return NULL;
 502
 503         psock->sk = sk;
 504         psock->eval =  __SK_NONE;
 505
 506         INIT_LIST_HEAD(&psock->link);
 507         spin_lock_init(&psock->link_lock);
 508
 509         INIT_WORK(&psock->work, sk_psock_backlog);
 510         INIT_LIST_HEAD(&psock->ingress_msg);
 511         skb_queue_head_init(&psock->ingress_skb);
 512
 513         sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
 514         refcount_set(&psock->refcnt, 1);
 515
 516         rcu_assign_sk_user_data_nocopy(sk, psock);
 517         sock_hold(sk);
 518
 519         return psock;
 520 }
 521 EXPORT_SYMBOL_GPL(sk_psock_init);
 522
 523 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
 524 {
 525         struct sk_psock_link *link;
 526
 527         spin_lock_bh(&psock->link_lock);
 528         link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
 529                                         list);
 530         if (link)
 531                 list_del(&link->list);
 532         spin_unlock_bh(&psock->link_lock);
 533         return link;
 534 }
 535
 536 void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
 537 {
 538         struct sk_msg *msg, *tmp;
 539
 540         list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
 541                 list_del(&msg->list);
 542                 sk_msg_free(psock->sk, msg);
 543                 kfree(msg);
 544         }
 545 }
 546
 547 static void sk_psock_zap_ingress(struct sk_psock *psock)
 548 {
 549         __skb_queue_purge(&psock->ingress_skb);
 550         __sk_psock_purge_ingress_msg(psock);
 551 }
 552
 553 static void sk_psock_link_destroy(struct sk_psock *psock)
 554 {
 555         struct sk_psock_link *link, *tmp;
 556
 557         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 558                 list_del(&link->list);
 559                 sk_psock_free_link(link);
 560         }
 561 }
 562
 563 static void sk_psock_destroy_deferred(struct work_struct *gc)
 564 {
 565         struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
 566
 567         /* No sk_callback_lock since already detached. */
 568
 569         /* Parser has been stopped */
 570         if (psock->progs.skb_parser)
 571                 strp_done(&psock->parser.strp);
 572
 573         cancel_work_sync(&psock->work);
 574
 575         psock_progs_drop(&psock->progs);
 576
 577         sk_psock_link_destroy(psock);
 578         sk_psock_cork_free(psock);
 579         sk_psock_zap_ingress(psock);
 580
 581         if (psock->sk_redir)
 582                 sock_put(psock->sk_redir);
 583         sock_put(psock->sk);
 584         kfree(psock);
 585 }
 586
 587 void sk_psock_destroy(struct rcu_head *rcu)
 588 {
 589         struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
 590
 591         INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
 592         schedule_work(&psock->gc);
 593 }
 594 EXPORT_SYMBOL_GPL(sk_psock_destroy);
 595
 596 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 597 {
 598         sk_psock_cork_free(psock);
 599         sk_psock_zap_ingress(psock);
 600
 601         write_lock_bh(&sk->sk_callback_lock);
 602         sk_psock_restore_proto(sk, psock);
 603         rcu_assign_sk_user_data(sk, NULL);
 604         if (psock->progs.skb_parser)
 605                 sk_psock_stop_strp(sk, psock);
 606         write_unlock_bh(&sk->sk_callback_lock);
 607         sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 608
 609         call_rcu(&psock->rcu, sk_psock_destroy);
 610 }
 611 EXPORT_SYMBOL_GPL(sk_psock_drop);
 612
 613 static int sk_psock_map_verd(int verdict, bool redir)
 614 {
 615         switch (verdict) {
 616         case SK_PASS:
 617                 return redir ? __SK_REDIRECT : __SK_PASS;
 618         case SK_DROP:
 619         default:
 620                 break;
 621         }
 622
 623         return __SK_DROP;
 624 }
 625
 626 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 627                          struct sk_msg *msg)
 628 {
 629         struct bpf_prog *prog;
 630         int ret;
 631
 632         rcu_read_lock();
 633         prog = READ_ONCE(psock->progs.msg_parser);
 634         if (unlikely(!prog)) {
 635                 ret = __SK_PASS;
 636                 goto out;
 637         }
 638
 639         sk_msg_compute_data_pointers(msg);
 640         msg->sk = sk;
 641         ret = bpf_prog_run_pin_on_cpu(prog, msg);
 642         ret = sk_psock_map_verd(ret, msg->sk_redir);
 643         psock->apply_bytes = msg->apply_bytes;
 644         if (ret == __SK_REDIRECT) {
 645                 if (psock->sk_redir)
 646                         sock_put(psock->sk_redir);
 647                 psock->sk_redir = msg->sk_redir;
 648                 if (!psock->sk_redir) {
 649                         ret = __SK_DROP;
 650                         goto out;
 651                 }
 652                 sock_hold(psock->sk_redir);
 653         }
 654 out:
 655         rcu_read_unlock();
 656         return ret;
 657 }
 658 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
 659
 660 static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
 661                             struct sk_buff *skb)
 662 {
 663         int ret;
 664
 665         skb->sk = psock->sk;
 666         bpf_compute_data_end_sk_skb(skb);
 667         ret = bpf_prog_run_pin_on_cpu(prog, skb);
 668         /* strparser clones the skb before handing it to a upper layer,
 669          * meaning skb_orphan has been called. We NULL sk on the way out
 670          * to ensure we don't trigger a BUG_ON() in skb/sk operations
 671          * later and because we are not charging the memory of this skb
 672          * to any socket yet.
 673          */
 674         skb->sk = NULL;
 675         return ret;
 676 }
 677
 678 static struct sk_psock *sk_psock_from_strp(struct strparser *strp)
 679 {
 680         struct sk_psock_parser *parser;
 681
 682         parser = container_of(strp, struct sk_psock_parser, strp);
 683         return container_of(parser, struct sk_psock, parser);
 684 }
 685
 686 static void sk_psock_skb_redirect(struct sk_buff *skb)
 687 {
 688         struct sk_psock *psock_other;
 689         struct sock *sk_other;
 690         bool ingress;
 691
 692         sk_other = tcp_skb_bpf_redirect_fetch(skb);
 693         if (unlikely(!sk_other)) {
 694                 kfree_skb(skb);
 695                 return;
 696         }
 697         psock_other = sk_psock(sk_other);
 698         if (!psock_other || sock_flag(sk_other, SOCK_DEAD) ||
 699             !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
 700                 kfree_skb(skb);
 701                 return;
 702         }
 703
 704         ingress = tcp_skb_bpf_ingress(skb);
 705         if ((!ingress && sock_writeable(sk_other)) ||
 706             (ingress &&
 707              atomic_read(&sk_other->sk_rmem_alloc) <=
 708              sk_other->sk_rcvbuf)) {
 709                 if (!ingress)
 710                         skb_set_owner_w(skb, sk_other);
 711                 skb_queue_tail(&psock_other->ingress_skb, skb);
 712                 schedule_work(&psock_other->work);
 713         } else {
 714                 kfree_skb(skb);
 715         }
 716 }
 717
 718 static void sk_psock_tls_verdict_apply(struct sk_buff *skb, int verdict)
 719 {
 720         switch (verdict) {
 721         case __SK_REDIRECT:
 722                 sk_psock_skb_redirect(skb);
 723                 break;
 724         case __SK_PASS:
 725         case __SK_DROP:
 726         default:
 727                 break;
 728         }
 729 }
 730
 731 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 732 {
 733         struct bpf_prog *prog;
 734         int ret = __SK_PASS;
 735
 736         rcu_read_lock();
 737         prog = READ_ONCE(psock->progs.skb_verdict);
 738         if (likely(prog)) {
 739                 tcp_skb_bpf_redirect_clear(skb);
 740                 ret = sk_psock_bpf_run(psock, prog, skb);
 741                 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
 742         }
 743         sk_psock_tls_verdict_apply(skb, ret);
 744         rcu_read_unlock();
 745         return ret;
 746 }
 747 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
 748
 749 static void sk_psock_verdict_apply(struct sk_psock *psock,
 750                                    struct sk_buff *skb, int verdict)
 751 {
 752         struct sock *sk_other;
 753
 754         switch (verdict) {
 755         case __SK_PASS:
 756                 sk_other = psock->sk;
 757                 if (sock_flag(sk_other, SOCK_DEAD) ||
 758                     !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 759                         goto out_free;
 760                 }
 761                 if (atomic_read(&sk_other->sk_rmem_alloc) <=
 762                     sk_other->sk_rcvbuf) {
 763                         struct tcp_skb_cb *tcp = TCP_SKB_CB(skb);
 764
 765                         tcp->bpf.flags |= BPF_F_INGRESS;
 766                         skb_queue_tail(&psock->ingress_skb, skb);
 767                         schedule_work(&psock->work);
 768                         break;
 769                 }
 770                 goto out_free;
 771         case __SK_REDIRECT:
 772                 sk_psock_skb_redirect(skb);
 773                 break;
 774         case __SK_DROP:
 775                 /* fall-through */
 776         default:
 777 out_free:
 778                 kfree_skb(skb);
 779         }
 780 }
 781
 782 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
 783 {
 784         struct sk_psock *psock;
 785         struct bpf_prog *prog;
 786         int ret = __SK_DROP;
 787         struct sock *sk;
 788
 789         rcu_read_lock();
 790         sk = strp->sk;
 791         psock = sk_psock(sk);
 792         if (unlikely(!psock)) {
 793                 kfree_skb(skb);
 794                 goto out;
 795         }
 796         prog = READ_ONCE(psock->progs.skb_verdict);
 797         if (likely(prog)) {
 798                 skb_orphan(skb);
 799                 tcp_skb_bpf_redirect_clear(skb);
 800                 ret = sk_psock_bpf_run(psock, prog, skb);
 801                 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
 802         }
 803         sk_psock_verdict_apply(psock, skb, ret);
 804 out:
 805         rcu_read_unlock();
 806 }
 807
 808 static int sk_psock_strp_read_done(struct strparser *strp, int err)
 809 {
 810         return err;
 811 }
 812
 813 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
 814 {
 815         struct sk_psock *psock = sk_psock_from_strp(strp);
 816         struct bpf_prog *prog;
 817         int ret = skb->len;
 818
 819         rcu_read_lock();
 820         prog = READ_ONCE(psock->progs.skb_parser);
 821         if (likely(prog))
 822                 ret = sk_psock_bpf_run(psock, prog, skb);
 823         rcu_read_unlock();
 824         return ret;
 825 }
 826
 827 /* Called with socket lock held. */
 828 static void sk_psock_strp_data_ready(struct sock *sk)
 829 {
 830         struct sk_psock *psock;
 831
 832         rcu_read_lock();
 833         psock = sk_psock(sk);
 834         if (likely(psock)) {
 835                 if (tls_sw_has_ctx_rx(sk)) {
 836                         psock->parser.saved_data_ready(sk);
 837                 } else {
 838                         write_lock_bh(&sk->sk_callback_lock);
 839                         strp_data_ready(&psock->parser.strp);
 840                         write_unlock_bh(&sk->sk_callback_lock);
 841                 }
 842         }
 843         rcu_read_unlock();
 844 }
 845
 846 static void sk_psock_write_space(struct sock *sk)
 847 {
 848         struct sk_psock *psock;
 849         void (*write_space)(struct sock *sk) = NULL;
 850
 851         rcu_read_lock();
 852         psock = sk_psock(sk);
 853         if (likely(psock)) {
 854                 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 855                         schedule_work(&psock->work);
 856                 write_space = psock->saved_write_space;
 857         }
 858         rcu_read_unlock();
 859         if (write_space)
 860                 write_space(sk);
 861 }
 862
 863 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 864 {
 865         static const struct strp_callbacks cb = {
 866                 .rcv_msg        = sk_psock_strp_read,
 867                 .read_sock_done = sk_psock_strp_read_done,
 868                 .parse_msg      = sk_psock_strp_parse,
 869         };
 870
 871         psock->parser.enabled = false;
 872         return strp_init(&psock->parser.strp, sk, &cb);
 873 }
 874
 875 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 876 {
 877         struct sk_psock_parser *parser = &psock->parser;
 878
 879         if (parser->enabled)
 880                 return;
 881
 882         parser->saved_data_ready = sk->sk_data_ready;
 883         sk->sk_data_ready = sk_psock_strp_data_ready;
 884         sk->sk_write_space = sk_psock_write_space;
 885         parser->enabled = true;
 886 }
 887
 888 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 889 {
 890         struct sk_psock_parser *parser = &psock->parser;
 891
 892         if (!parser->enabled)
 893                 return;
 894
 895         sk->sk_data_ready = parser->saved_data_ready;
 896         parser->saved_data_ready = NULL;
 897         strp_stop(&parser->strp);
 898         parser->enabled = false;
 899 }