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         /* When the skb owns the memory we free it from consume_skb path. */
 174         if (!msg->skb) {
 175                 if (charge)
 176                         sk_mem_uncharge(sk, len);
 177                 put_page(sg_page(sge));
 178         }
 179         memset(sge, 0, sizeof(*sge));
 180         return len;
 181 }
 182
 183 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
 184                          bool charge)
 185 {
 186         struct scatterlist *sge = sk_msg_elem(msg, i);
 187         int freed = 0;
 188
 189         while (msg->sg.size) {
 190                 msg->sg.size -= sge->length;
 191                 freed += sk_msg_free_elem(sk, msg, i, charge);
 192                 sk_msg_iter_var_next(i);
 193                 sk_msg_check_to_free(msg, i, msg->sg.size);
 194                 sge = sk_msg_elem(msg, i);
 195         }
 196         consume_skb(msg->skb);
 197         sk_msg_init(msg);
 198         return freed;
 199 }
 200
 201 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
 202 {
 203         return __sk_msg_free(sk, msg, msg->sg.start, false);
 204 }
 205 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
 206
 207 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
 208 {
 209         return __sk_msg_free(sk, msg, msg->sg.start, true);
 210 }
 211 EXPORT_SYMBOL_GPL(sk_msg_free);
 212
 213 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
 214                                   u32 bytes, bool charge)
 215 {
 216         struct scatterlist *sge;
 217         u32 i = msg->sg.start;
 218
 219         while (bytes) {
 220                 sge = sk_msg_elem(msg, i);
 221                 if (!sge->length)
 222                         break;
 223                 if (bytes < sge->length) {
 224                         if (charge)
 225                                 sk_mem_uncharge(sk, bytes);
 226                         sge->length -= bytes;
 227                         sge->offset += bytes;
 228                         msg->sg.size -= bytes;
 229                         break;
 230                 }
 231
 232                 msg->sg.size -= sge->length;
 233                 bytes -= sge->length;
 234                 sk_msg_free_elem(sk, msg, i, charge);
 235                 sk_msg_iter_var_next(i);
 236                 sk_msg_check_to_free(msg, i, bytes);
 237         }
 238         msg->sg.start = i;
 239 }
 240
 241 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
 242 {
 243         __sk_msg_free_partial(sk, msg, bytes, true);
 244 }
 245 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
 246
 247 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 248                                   u32 bytes)
 249 {
 250         __sk_msg_free_partial(sk, msg, bytes, false);
 251 }
 252
 253 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
 254 {
 255         int trim = msg->sg.size - len;
 256         u32 i = msg->sg.end;
 257
 258         if (trim <= 0) {
 259                 WARN_ON(trim < 0);
 260                 return;
 261         }
 262
 263         sk_msg_iter_var_prev(i);
 264         msg->sg.size = len;
 265         while (msg->sg.data[i].length &&
 266                trim >= msg->sg.data[i].length) {
 267                 trim -= msg->sg.data[i].length;
 268                 sk_msg_free_elem(sk, msg, i, true);
 269                 sk_msg_iter_var_prev(i);
 270                 if (!trim)
 271                         goto out;
 272         }
 273
 274         msg->sg.data[i].length -= trim;
 275         sk_mem_uncharge(sk, trim);
 276         /* Adjust copybreak if it falls into the trimmed part of last buf */
 277         if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
 278                 msg->sg.copybreak = msg->sg.data[i].length;
 279 out:
 280         sk_msg_iter_var_next(i);
 281         msg->sg.end = i;
 282
 283         /* If we trim data a full sg elem before curr pointer update
 284          * copybreak and current so that any future copy operations
 285          * start at new copy location.
 286          * However trimed data that has not yet been used in a copy op
 287          * does not require an update.
 288          */
 289         if (!msg->sg.size) {
 290                 msg->sg.curr = msg->sg.start;
 291                 msg->sg.copybreak = 0;
 292         } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
 293                    sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
 294                 sk_msg_iter_var_prev(i);
 295                 msg->sg.curr = i;
 296                 msg->sg.copybreak = msg->sg.data[i].length;
 297         }
 298 }
 299 EXPORT_SYMBOL_GPL(sk_msg_trim);
 300
 301 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 302                               struct sk_msg *msg, u32 bytes)
 303 {
 304         int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
 305         const int to_max_pages = MAX_MSG_FRAGS;
 306         struct page *pages[MAX_MSG_FRAGS];
 307         ssize_t orig, copied, use, offset;
 308
 309         orig = msg->sg.size;
 310         while (bytes > 0) {
 311                 i = 0;
 312                 maxpages = to_max_pages - num_elems;
 313                 if (maxpages == 0) {
 314                         ret = -EFAULT;
 315                         goto out;
 316                 }
 317
 318                 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
 319                                             &offset);
 320                 if (copied <= 0) {
 321                         ret = -EFAULT;
 322                         goto out;
 323                 }
 324
 325                 iov_iter_advance(from, copied);
 326                 bytes -= copied;
 327                 msg->sg.size += copied;
 328
 329                 while (copied) {
 330                         use = min_t(int, copied, PAGE_SIZE - offset);
 331                         sg_set_page(&msg->sg.data[msg->sg.end],
 332                                     pages[i], use, offset);
 333                         sg_unmark_end(&msg->sg.data[msg->sg.end]);
 334                         sk_mem_charge(sk, use);
 335
 336                         offset = 0;
 337                         copied -= use;
 338                         sk_msg_iter_next(msg, end);
 339                         num_elems++;
 340                         i++;
 341                 }
 342                 /* When zerocopy is mixed with sk_msg_*copy* operations we
 343                  * may have a copybreak set in this case clear and prefer
 344                  * zerocopy remainder when possible.
 345                  */
 346                 msg->sg.copybreak = 0;
 347                 msg->sg.curr = msg->sg.end;
 348         }
 349 out:
 350         /* Revert iov_iter updates, msg will need to use 'trim' later if it
 351          * also needs to be cleared.
 352          */
 353         if (ret)
 354                 iov_iter_revert(from, msg->sg.size - orig);
 355         return ret;
 356 }
 357 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
 358
 359 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 360                              struct sk_msg *msg, u32 bytes)
 361 {
 362         int ret = -ENOSPC, i = msg->sg.curr;
 363         struct scatterlist *sge;
 364         u32 copy, buf_size;
 365         void *to;
 366
 367         do {
 368                 sge = sk_msg_elem(msg, i);
 369                 /* This is possible if a trim operation shrunk the buffer */
 370                 if (msg->sg.copybreak >= sge->length) {
 371                         msg->sg.copybreak = 0;
 372                         sk_msg_iter_var_next(i);
 373                         if (i == msg->sg.end)
 374                                 break;
 375                         sge = sk_msg_elem(msg, i);
 376                 }
 377
 378                 buf_size = sge->length - msg->sg.copybreak;
 379                 copy = (buf_size > bytes) ? bytes : buf_size;
 380                 to = sg_virt(sge) + msg->sg.copybreak;
 381                 msg->sg.copybreak += copy;
 382                 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
 383                         ret = copy_from_iter_nocache(to, copy, from);
 384                 else
 385                         ret = copy_from_iter(to, copy, from);
 386                 if (ret != copy) {
 387                         ret = -EFAULT;
 388                         goto out;
 389                 }
 390                 bytes -= copy;
 391                 if (!bytes)
 392                         break;
 393                 msg->sg.copybreak = 0;
 394                 sk_msg_iter_var_next(i);
 395         } while (i != msg->sg.end);
 396 out:
 397         msg->sg.curr = i;
 398         return ret;
 399 }
 400 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
 401
 402 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
 403                                                   struct sk_buff *skb)
 404 {
 405         struct sk_msg *msg;
 406
 407         if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
 408                 return NULL;
 409
 410         if (!sk_rmem_schedule(sk, skb, skb->truesize))
 411                 return NULL;
 412
 413         msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_KERNEL);
 414         if (unlikely(!msg))
 415                 return NULL;
 416
 417         sk_msg_init(msg);
 418         return msg;
 419 }
 420
 421 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 422                                         struct sk_psock *psock,
 423                                         struct sock *sk,
 424                                         struct sk_msg *msg)
 425 {
 426         int num_sge, copied;
 427
 428         /* skb linearize may fail with ENOMEM, but lets simply try again
 429          * later if this happens. Under memory pressure we don't want to
 430          * drop the skb. We need to linearize the skb so that the mapping
 431          * in skb_to_sgvec can not error.
 432          */
 433         if (skb_linearize(skb))
 434                 return -EAGAIN;
 435         num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
 436         if (unlikely(num_sge < 0)) {
 437                 kfree(msg);
 438                 return num_sge;
 439         }
 440
 441         copied = skb->len;
 442         msg->sg.start = 0;
 443         msg->sg.size = copied;
 444         msg->sg.end = num_sge;
 445         msg->skb = skb;
 446
 447         sk_psock_queue_msg(psock, msg);
 448         sk_psock_data_ready(sk, psock);
 449         return copied;
 450 }
 451
 452 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb);
 453
 454 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 455 {
 456         struct sock *sk = psock->sk;
 457         struct sk_msg *msg;
 458
 459         /* If we are receiving on the same sock skb->sk is already assigned,
 460          * skip memory accounting and owner transition seeing it already set
 461          * correctly.
 462          */
 463         if (unlikely(skb->sk == sk))
 464                 return sk_psock_skb_ingress_self(psock, skb);
 465         msg = sk_psock_create_ingress_msg(sk, skb);
 466         if (!msg)
 467                 return -EAGAIN;
 468
 469         /* This will transition ownership of the data from the socket where
 470          * the BPF program was run initiating the redirect to the socket
 471          * we will eventually receive this data on. The data will be released
 472          * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
 473          * into user buffers.
 474          */
 475         skb_set_owner_r(skb, sk);
 476         return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
 477 }
 478
 479 /* Puts an skb on the ingress queue of the socket already assigned to the
 480  * skb. In this case we do not need to check memory limits or skb_set_owner_r
 481  * because the skb is already accounted for here.
 482  */
 483 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb)
 484 {
 485         struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
 486         struct sock *sk = psock->sk;
 487
 488         if (unlikely(!msg))
 489                 return -EAGAIN;
 490         sk_msg_init(msg);
 491         return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
 492 }
 493
 494 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 495                                u32 off, u32 len, bool ingress)
 496 {
 497         if (!ingress) {
 498                 if (!sock_writeable(psock->sk))
 499                         return -EAGAIN;
 500                 return skb_send_sock(psock->sk, skb, off, len);
 501         }
 502         return sk_psock_skb_ingress(psock, skb);
 503 }
 504
 505 static void sk_psock_backlog(struct work_struct *work)
 506 {
 507         struct sk_psock *psock = container_of(work, struct sk_psock, work);
 508         struct sk_psock_work_state *state = &psock->work_state;
 509         struct sk_buff *skb;
 510         bool ingress;
 511         u32 len, off;
 512         int ret;
 513
 514         mutex_lock(&psock->work_mutex);
 515         if (state->skb) {
 516                 skb = state->skb;
 517                 len = state->len;
 518                 off = state->off;
 519                 state->skb = NULL;
 520                 goto start;
 521         }
 522
 523         while ((skb = skb_dequeue(&psock->ingress_skb))) {
 524                 len = skb->len;
 525                 off = 0;
 526 start:
 527                 ingress = skb_bpf_ingress(skb);
 528                 skb_bpf_redirect_clear(skb);
 529                 do {
 530                         ret = -EIO;
 531                         if (!sock_flag(psock->sk, SOCK_DEAD))
 532                                 ret = sk_psock_handle_skb(psock, skb, off,
 533                                                           len, ingress);
 534                         if (ret <= 0) {
 535                                 if (ret == -EAGAIN) {
 536                                         state->skb = skb;
 537                                         state->len = len;
 538                                         state->off = off;
 539                                         goto end;
 540                                 }
 541                                 /* Hard errors break pipe and stop xmit. */
 542                                 sk_psock_report_error(psock, ret ? -ret : EPIPE);
 543                                 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 544                                 kfree_skb(skb);
 545                                 goto end;
 546                         }
 547                         off += ret;
 548                         len -= ret;
 549                 } while (len);
 550
 551                 if (!ingress)
 552                         kfree_skb(skb);
 553         }
 554 end:
 555         mutex_unlock(&psock->work_mutex);
 556 }
 557
 558 struct sk_psock *sk_psock_init(struct sock *sk, int node)
 559 {
 560         struct sk_psock *psock;
 561         struct proto *prot;
 562
 563         write_lock_bh(&sk->sk_callback_lock);
 564
 565         if (inet_csk_has_ulp(sk)) {
 566                 psock = ERR_PTR(-EINVAL);
 567                 goto out;
 568         }
 569
 570         if (sk->sk_user_data) {
 571                 psock = ERR_PTR(-EBUSY);
 572                 goto out;
 573         }
 574
 575         psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
 576         if (!psock) {
 577                 psock = ERR_PTR(-ENOMEM);
 578                 goto out;
 579         }
 580
 581         prot = READ_ONCE(sk->sk_prot);
 582         psock->sk = sk;
 583         psock->eval = __SK_NONE;
 584         psock->sk_proto = prot;
 585         psock->saved_unhash = prot->unhash;
 586         psock->saved_close = prot->close;
 587         psock->saved_write_space = sk->sk_write_space;
 588
 589         INIT_LIST_HEAD(&psock->link);
 590         spin_lock_init(&psock->link_lock);
 591
 592         INIT_WORK(&psock->work, sk_psock_backlog);
 593         mutex_init(&psock->work_mutex);
 594         INIT_LIST_HEAD(&psock->ingress_msg);
 595         spin_lock_init(&psock->ingress_lock);
 596         skb_queue_head_init(&psock->ingress_skb);
 597
 598         sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
 599         refcount_set(&psock->refcnt, 1);
 600
 601         rcu_assign_sk_user_data_nocopy(sk, psock);
 602         sock_hold(sk);
 603
 604 out:
 605         write_unlock_bh(&sk->sk_callback_lock);
 606         return psock;
 607 }
 608 EXPORT_SYMBOL_GPL(sk_psock_init);
 609
 610 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
 611 {
 612         struct sk_psock_link *link;
 613
 614         spin_lock_bh(&psock->link_lock);
 615         link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
 616                                         list);
 617         if (link)
 618                 list_del(&link->list);
 619         spin_unlock_bh(&psock->link_lock);
 620         return link;
 621 }
 622
 623 static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
 624 {
 625         struct sk_msg *msg, *tmp;
 626
 627         list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
 628                 list_del(&msg->list);
 629                 sk_msg_free(psock->sk, msg);
 630                 kfree(msg);
 631         }
 632 }
 633
 634 static void __sk_psock_zap_ingress(struct sk_psock *psock)
 635 {
 636         struct sk_buff *skb;
 637
 638         while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
 639                 skb_bpf_redirect_clear(skb);
 640                 kfree_skb(skb);
 641         }
 642         __sk_psock_purge_ingress_msg(psock);
 643 }
 644
 645 static void sk_psock_link_destroy(struct sk_psock *psock)
 646 {
 647         struct sk_psock_link *link, *tmp;
 648
 649         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 650                 list_del(&link->list);
 651                 sk_psock_free_link(link);
 652         }
 653 }
 654
 655 void sk_psock_stop(struct sk_psock *psock, bool wait)
 656 {
 657         spin_lock_bh(&psock->ingress_lock);
 658         sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 659         sk_psock_cork_free(psock);
 660         __sk_psock_zap_ingress(psock);
 661         spin_unlock_bh(&psock->ingress_lock);
 662
 663         if (wait)
 664                 cancel_work_sync(&psock->work);
 665 }
 666
 667 static void sk_psock_done_strp(struct sk_psock *psock);
 668
 669 static void sk_psock_destroy(struct work_struct *work)
 670 {
 671         struct sk_psock *psock = container_of(to_rcu_work(work),
 672                                               struct sk_psock, rwork);
 673         /* No sk_callback_lock since already detached. */
 674
 675         sk_psock_done_strp(psock);
 676
 677         cancel_work_sync(&psock->work);
 678         mutex_destroy(&psock->work_mutex);
 679
 680         psock_progs_drop(&psock->progs);
 681
 682         sk_psock_link_destroy(psock);
 683         sk_psock_cork_free(psock);
 684
 685         if (psock->sk_redir)
 686                 sock_put(psock->sk_redir);
 687         sock_put(psock->sk);
 688         kfree(psock);
 689 }
 690
 691 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 692 {
 693         sk_psock_stop(psock, false);
 694
 695         write_lock_bh(&sk->sk_callback_lock);
 696         sk_psock_restore_proto(sk, psock);
 697         rcu_assign_sk_user_data(sk, NULL);
 698         if (psock->progs.stream_parser)
 699                 sk_psock_stop_strp(sk, psock);
 700         else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
 701                 sk_psock_stop_verdict(sk, psock);
 702         write_unlock_bh(&sk->sk_callback_lock);
 703
 704         INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
 705         queue_rcu_work(system_wq, &psock->rwork);
 706 }
 707 EXPORT_SYMBOL_GPL(sk_psock_drop);
 708
 709 static int sk_psock_map_verd(int verdict, bool redir)
 710 {
 711         switch (verdict) {
 712         case SK_PASS:
 713                 return redir ? __SK_REDIRECT : __SK_PASS;
 714         case SK_DROP:
 715         default:
 716                 break;
 717         }
 718
 719         return __SK_DROP;
 720 }
 721
 722 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 723                          struct sk_msg *msg)
 724 {
 725         struct bpf_prog *prog;
 726         int ret;
 727
 728         rcu_read_lock();
 729         prog = READ_ONCE(psock->progs.msg_parser);
 730         if (unlikely(!prog)) {
 731                 ret = __SK_PASS;
 732                 goto out;
 733         }
 734
 735         sk_msg_compute_data_pointers(msg);
 736         msg->sk = sk;
 737         ret = bpf_prog_run_pin_on_cpu(prog, msg);
 738         ret = sk_psock_map_verd(ret, msg->sk_redir);
 739         psock->apply_bytes = msg->apply_bytes;
 740         if (ret == __SK_REDIRECT) {
 741                 if (psock->sk_redir)
 742                         sock_put(psock->sk_redir);
 743                 psock->sk_redir = msg->sk_redir;
 744                 if (!psock->sk_redir) {
 745                         ret = __SK_DROP;
 746                         goto out;
 747                 }
 748                 sock_hold(psock->sk_redir);
 749         }
 750 out:
 751         rcu_read_unlock();
 752         return ret;
 753 }
 754 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
 755
 756 static void sk_psock_skb_redirect(struct sk_buff *skb)
 757 {
 758         struct sk_psock *psock_other;
 759         struct sock *sk_other;
 760
 761         sk_other = skb_bpf_redirect_fetch(skb);
 762         /* This error is a buggy BPF program, it returned a redirect
 763          * return code, but then didn't set a redirect interface.
 764          */
 765         if (unlikely(!sk_other)) {
 766                 kfree_skb(skb);
 767                 return;
 768         }
 769         psock_other = sk_psock(sk_other);
 770         /* This error indicates the socket is being torn down or had another
 771          * error that caused the pipe to break. We can't send a packet on
 772          * a socket that is in this state so we drop the skb.
 773          */
 774         if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
 775                 kfree_skb(skb);
 776                 return;
 777         }
 778         spin_lock_bh(&psock_other->ingress_lock);
 779         if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
 780                 spin_unlock_bh(&psock_other->ingress_lock);
 781                 kfree_skb(skb);
 782                 return;
 783         }
 784
 785         skb_queue_tail(&psock_other->ingress_skb, skb);
 786         schedule_work(&psock_other->work);
 787         spin_unlock_bh(&psock_other->ingress_lock);
 788 }
 789
 790 static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict)
 791 {
 792         switch (verdict) {
 793         case __SK_REDIRECT:
 794                 skb_set_owner_r(skb, sk);
 795                 sk_psock_skb_redirect(skb);
 796                 break;
 797         case __SK_PASS:
 798         case __SK_DROP:
 799         default:
 800                 break;
 801         }
 802 }
 803
 804 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 805 {
 806         struct bpf_prog *prog;
 807         int ret = __SK_PASS;
 808
 809         rcu_read_lock();
 810         prog = READ_ONCE(psock->progs.stream_verdict);
 811         if (likely(prog)) {
 812                 /* We skip full set_owner_r here because if we do a SK_PASS
 813                  * or SK_DROP we can skip skb memory accounting and use the
 814                  * TLS context.
 815                  */
 816                 skb->sk = psock->sk;
 817                 skb_dst_drop(skb);
 818                 skb_bpf_redirect_clear(skb);
 819                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 820                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 821                 skb->sk = NULL;
 822         }
 823         sk_psock_tls_verdict_apply(skb, psock->sk, ret);
 824         rcu_read_unlock();
 825         return ret;
 826 }
 827 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
 828
 829 static void sk_psock_verdict_apply(struct sk_psock *psock,
 830                                    struct sk_buff *skb, int verdict)
 831 {
 832         struct sock *sk_other;
 833         int err = -EIO;
 834
 835         switch (verdict) {
 836         case __SK_PASS:
 837                 sk_other = psock->sk;
 838                 if (sock_flag(sk_other, SOCK_DEAD) ||
 839                     !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 840                         goto out_free;
 841                 }
 842
 843                 skb_bpf_set_ingress(skb);
 844
 845                 /* If the queue is empty then we can submit directly
 846                  * into the msg queue. If its not empty we have to
 847                  * queue work otherwise we may get OOO data. Otherwise,
 848                  * if sk_psock_skb_ingress errors will be handled by
 849                  * retrying later from workqueue.
 850                  */
 851                 if (skb_queue_empty(&psock->ingress_skb)) {
 852                         err = sk_psock_skb_ingress_self(psock, skb);
 853                 }
 854                 if (err < 0) {
 855                         spin_lock_bh(&psock->ingress_lock);
 856                         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 857                                 skb_queue_tail(&psock->ingress_skb, skb);
 858                                 schedule_work(&psock->work);
 859                         }
 860                         spin_unlock_bh(&psock->ingress_lock);
 861                 }
 862                 break;
 863         case __SK_REDIRECT:
 864                 sk_psock_skb_redirect(skb);
 865                 break;
 866         case __SK_DROP:
 867         default:
 868 out_free:
 869                 kfree_skb(skb);
 870         }
 871 }
 872
 873 static void sk_psock_write_space(struct sock *sk)
 874 {
 875         struct sk_psock *psock;
 876         void (*write_space)(struct sock *sk) = NULL;
 877
 878         rcu_read_lock();
 879         psock = sk_psock(sk);
 880         if (likely(psock)) {
 881                 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 882                         schedule_work(&psock->work);
 883                 write_space = psock->saved_write_space;
 884         }
 885         rcu_read_unlock();
 886         if (write_space)
 887                 write_space(sk);
 888 }
 889
 890 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 891 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
 892 {
 893         struct sk_psock *psock;
 894         struct bpf_prog *prog;
 895         int ret = __SK_DROP;
 896         struct sock *sk;
 897
 898         rcu_read_lock();
 899         sk = strp->sk;
 900         psock = sk_psock(sk);
 901         if (unlikely(!psock)) {
 902                 kfree_skb(skb);
 903                 goto out;
 904         }
 905         skb_set_owner_r(skb, sk);
 906         prog = READ_ONCE(psock->progs.stream_verdict);
 907         if (likely(prog)) {
 908                 skb_dst_drop(skb);
 909                 skb_bpf_redirect_clear(skb);
 910                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 911                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 912         }
 913         sk_psock_verdict_apply(psock, skb, ret);
 914 out:
 915         rcu_read_unlock();
 916 }
 917
 918 static int sk_psock_strp_read_done(struct strparser *strp, int err)
 919 {
 920         return err;
 921 }
 922
 923 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
 924 {
 925         struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
 926         struct bpf_prog *prog;
 927         int ret = skb->len;
 928
 929         rcu_read_lock();
 930         prog = READ_ONCE(psock->progs.stream_parser);
 931         if (likely(prog)) {
 932                 skb->sk = psock->sk;
 933                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 934                 skb->sk = NULL;
 935         }
 936         rcu_read_unlock();
 937         return ret;
 938 }
 939
 940 /* Called with socket lock held. */
 941 static void sk_psock_strp_data_ready(struct sock *sk)
 942 {
 943         struct sk_psock *psock;
 944
 945         rcu_read_lock();
 946         psock = sk_psock(sk);
 947         if (likely(psock)) {
 948                 if (tls_sw_has_ctx_rx(sk)) {
 949                         psock->saved_data_ready(sk);
 950                 } else {
 951                         write_lock_bh(&sk->sk_callback_lock);
 952                         strp_data_ready(&psock->strp);
 953                         write_unlock_bh(&sk->sk_callback_lock);
 954                 }
 955         }
 956         rcu_read_unlock();
 957 }
 958
 959 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 960 {
 961         static const struct strp_callbacks cb = {
 962                 .rcv_msg        = sk_psock_strp_read,
 963                 .read_sock_done = sk_psock_strp_read_done,
 964                 .parse_msg      = sk_psock_strp_parse,
 965         };
 966
 967         return strp_init(&psock->strp, sk, &cb);
 968 }
 969
 970 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 971 {
 972         if (psock->saved_data_ready)
 973                 return;
 974
 975         psock->saved_data_ready = sk->sk_data_ready;
 976         sk->sk_data_ready = sk_psock_strp_data_ready;
 977         sk->sk_write_space = sk_psock_write_space;
 978 }
 979
 980 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 981 {
 982         if (!psock->saved_data_ready)
 983                 return;
 984
 985         sk->sk_data_ready = psock->saved_data_ready;
 986         psock->saved_data_ready = NULL;
 987         strp_stop(&psock->strp);
 988 }
 989
 990 static void sk_psock_done_strp(struct sk_psock *psock)
 991 {
 992         /* Parser has been stopped */
 993         if (psock->progs.stream_parser)
 994                 strp_done(&psock->strp);
 995 }
 996 #else
 997 static void sk_psock_done_strp(struct sk_psock *psock)
 998 {
 999 }
1000 #endif /* CONFIG_BPF_STREAM_PARSER */
1001
1002 static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
1003                                  unsigned int offset, size_t orig_len)
1004 {
1005         struct sock *sk = (struct sock *)desc->arg.data;
1006         struct sk_psock *psock;
1007         struct bpf_prog *prog;
1008         int ret = __SK_DROP;
1009         int len = skb->len;
1010
1011         /* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */
1012         skb = skb_clone(skb, GFP_ATOMIC);
1013         if (!skb) {
1014                 desc->error = -ENOMEM;
1015                 return 0;
1016         }
1017
1018         rcu_read_lock();
1019         psock = sk_psock(sk);
1020         if (unlikely(!psock)) {
1021                 len = 0;
1022                 kfree_skb(skb);
1023                 goto out;
1024         }
1025         skb_set_owner_r(skb, sk);
1026         prog = READ_ONCE(psock->progs.stream_verdict);
1027         if (!prog)
1028                 prog = READ_ONCE(psock->progs.skb_verdict);
1029         if (likely(prog)) {
1030                 skb_dst_drop(skb);
1031                 skb_bpf_redirect_clear(skb);
1032                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1033                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1034         }
1035         sk_psock_verdict_apply(psock, skb, ret);
1036 out:
1037         rcu_read_unlock();
1038         return len;
1039 }
1040
1041 static void sk_psock_verdict_data_ready(struct sock *sk)
1042 {
1043         struct socket *sock = sk->sk_socket;
1044         read_descriptor_t desc;
1045
1046         if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
1047                 return;
1048
1049         desc.arg.data = sk;
1050         desc.error = 0;
1051         desc.count = 1;
1052
1053         sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv);
1054 }
1055
1056 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1057 {
1058         if (psock->saved_data_ready)
1059                 return;
1060
1061         psock->saved_data_ready = sk->sk_data_ready;
1062         sk->sk_data_ready = sk_psock_verdict_data_ready;
1063         sk->sk_write_space = sk_psock_write_space;
1064 }
1065
1066 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1067 {
1068         if (!psock->saved_data_ready)
1069                 return;
1070
1071         sk->sk_data_ready = psock->saved_data_ready;
1072         psock->saved_data_ready = NULL;
1073 }