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 int sk_msg_wait_data(struct sock *sk, struct sk_psock *psock, int flags,
 403                      long timeo, int *err)
 404 {
 405         DEFINE_WAIT_FUNC(wait, woken_wake_function);
 406         int ret = 0;
 407
 408         if (sk->sk_shutdown & RCV_SHUTDOWN)
 409                 return 1;
 410
 411         if (!timeo)
 412                 return ret;
 413
 414         add_wait_queue(sk_sleep(sk), &wait);
 415         sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 416         ret = sk_wait_event(sk, &timeo,
 417                             !list_empty(&psock->ingress_msg) ||
 418                             !skb_queue_empty(&sk->sk_receive_queue), &wait);
 419         sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 420         remove_wait_queue(sk_sleep(sk), &wait);
 421         return ret;
 422 }
 423 EXPORT_SYMBOL_GPL(sk_msg_wait_data);
 424
 425 /* Receive sk_msg from psock->ingress_msg to @msg. */
 426 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 427                    int len, int flags)
 428 {
 429         struct iov_iter *iter = &msg->msg_iter;
 430         int peek = flags & MSG_PEEK;
 431         struct sk_msg *msg_rx;
 432         int i, copied = 0;
 433
 434         msg_rx = sk_psock_peek_msg(psock);
 435         while (copied != len) {
 436                 struct scatterlist *sge;
 437
 438                 if (unlikely(!msg_rx))
 439                         break;
 440
 441                 i = msg_rx->sg.start;
 442                 do {
 443                         struct page *page;
 444                         int copy;
 445
 446                         sge = sk_msg_elem(msg_rx, i);
 447                         copy = sge->length;
 448                         page = sg_page(sge);
 449                         if (copied + copy > len)
 450                                 copy = len - copied;
 451                         copy = copy_page_to_iter(page, sge->offset, copy, iter);
 452                         if (!copy)
 453                                 return copied ? copied : -EFAULT;
 454
 455                         copied += copy;
 456                         if (likely(!peek)) {
 457                                 sge->offset += copy;
 458                                 sge->length -= copy;
 459                                 if (!msg_rx->skb)
 460                                         sk_mem_uncharge(sk, copy);
 461                                 msg_rx->sg.size -= copy;
 462
 463                                 if (!sge->length) {
 464                                         sk_msg_iter_var_next(i);
 465                                         if (!msg_rx->skb)
 466                                                 put_page(page);
 467                                 }
 468                         } else {
 469                                 /* Lets not optimize peek case if copy_page_to_iter
 470                                  * didn't copy the entire length lets just break.
 471                                  */
 472                                 if (copy != sge->length)
 473                                         return copied;
 474                                 sk_msg_iter_var_next(i);
 475                         }
 476
 477                         if (copied == len)
 478                                 break;
 479                 } while (i != msg_rx->sg.end);
 480
 481                 if (unlikely(peek)) {
 482                         msg_rx = sk_psock_next_msg(psock, msg_rx);
 483                         if (!msg_rx)
 484                                 break;
 485                         continue;
 486                 }
 487
 488                 msg_rx->sg.start = i;
 489                 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
 490                         msg_rx = sk_psock_dequeue_msg(psock);
 491                         kfree_sk_msg(msg_rx);
 492                 }
 493                 msg_rx = sk_psock_peek_msg(psock);
 494         }
 495
 496         return copied;
 497 }
 498 EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
 499
 500 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
 501                                                   struct sk_buff *skb)
 502 {
 503         struct sk_msg *msg;
 504
 505         if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
 506                 return NULL;
 507
 508         if (!sk_rmem_schedule(sk, skb, skb->truesize))
 509                 return NULL;
 510
 511         msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_KERNEL);
 512         if (unlikely(!msg))
 513                 return NULL;
 514
 515         sk_msg_init(msg);
 516         return msg;
 517 }
 518
 519 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 520                                         struct sk_psock *psock,
 521                                         struct sock *sk,
 522                                         struct sk_msg *msg)
 523 {
 524         int num_sge, copied;
 525
 526         /* skb linearize may fail with ENOMEM, but lets simply try again
 527          * later if this happens. Under memory pressure we don't want to
 528          * drop the skb. We need to linearize the skb so that the mapping
 529          * in skb_to_sgvec can not error.
 530          */
 531         if (skb_linearize(skb))
 532                 return -EAGAIN;
 533         num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
 534         if (unlikely(num_sge < 0)) {
 535                 kfree(msg);
 536                 return num_sge;
 537         }
 538
 539         copied = skb->len;
 540         msg->sg.start = 0;
 541         msg->sg.size = copied;
 542         msg->sg.end = num_sge;
 543         msg->skb = skb;
 544
 545         sk_psock_queue_msg(psock, msg);
 546         sk_psock_data_ready(sk, psock);
 547         return copied;
 548 }
 549
 550 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb);
 551
 552 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 553 {
 554         struct sock *sk = psock->sk;
 555         struct sk_msg *msg;
 556
 557         /* If we are receiving on the same sock skb->sk is already assigned,
 558          * skip memory accounting and owner transition seeing it already set
 559          * correctly.
 560          */
 561         if (unlikely(skb->sk == sk))
 562                 return sk_psock_skb_ingress_self(psock, skb);
 563         msg = sk_psock_create_ingress_msg(sk, skb);
 564         if (!msg)
 565                 return -EAGAIN;
 566
 567         /* This will transition ownership of the data from the socket where
 568          * the BPF program was run initiating the redirect to the socket
 569          * we will eventually receive this data on. The data will be released
 570          * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
 571          * into user buffers.
 572          */
 573         skb_set_owner_r(skb, sk);
 574         return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
 575 }
 576
 577 /* Puts an skb on the ingress queue of the socket already assigned to the
 578  * skb. In this case we do not need to check memory limits or skb_set_owner_r
 579  * because the skb is already accounted for here.
 580  */
 581 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb)
 582 {
 583         struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
 584         struct sock *sk = psock->sk;
 585
 586         if (unlikely(!msg))
 587                 return -EAGAIN;
 588         sk_msg_init(msg);
 589         skb_set_owner_r(skb, sk);
 590         return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
 591 }
 592
 593 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 594                                u32 off, u32 len, bool ingress)
 595 {
 596         if (!ingress) {
 597                 if (!sock_writeable(psock->sk))
 598                         return -EAGAIN;
 599                 return skb_send_sock(psock->sk, skb, off, len);
 600         }
 601         return sk_psock_skb_ingress(psock, skb);
 602 }
 603
 604 static void sk_psock_backlog(struct work_struct *work)
 605 {
 606         struct sk_psock *psock = container_of(work, struct sk_psock, work);
 607         struct sk_psock_work_state *state = &psock->work_state;
 608         struct sk_buff *skb;
 609         bool ingress;
 610         u32 len, off;
 611         int ret;
 612
 613         mutex_lock(&psock->work_mutex);
 614         if (state->skb) {
 615                 skb = state->skb;
 616                 len = state->len;
 617                 off = state->off;
 618                 state->skb = NULL;
 619                 goto start;
 620         }
 621
 622         while ((skb = skb_dequeue(&psock->ingress_skb))) {
 623                 len = skb->len;
 624                 off = 0;
 625 start:
 626                 ingress = skb_bpf_ingress(skb);
 627                 skb_bpf_redirect_clear(skb);
 628                 do {
 629                         ret = -EIO;
 630                         if (!sock_flag(psock->sk, SOCK_DEAD))
 631                                 ret = sk_psock_handle_skb(psock, skb, off,
 632                                                           len, ingress);
 633                         if (ret <= 0) {
 634                                 if (ret == -EAGAIN) {
 635                                         state->skb = skb;
 636                                         state->len = len;
 637                                         state->off = off;
 638                                         goto end;
 639                                 }
 640                                 /* Hard errors break pipe and stop xmit. */
 641                                 sk_psock_report_error(psock, ret ? -ret : EPIPE);
 642                                 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 643                                 kfree_skb(skb);
 644                                 goto end;
 645                         }
 646                         off += ret;
 647                         len -= ret;
 648                 } while (len);
 649
 650                 if (!ingress)
 651                         kfree_skb(skb);
 652         }
 653 end:
 654         mutex_unlock(&psock->work_mutex);
 655 }
 656
 657 struct sk_psock *sk_psock_init(struct sock *sk, int node)
 658 {
 659         struct sk_psock *psock;
 660         struct proto *prot;
 661
 662         write_lock_bh(&sk->sk_callback_lock);
 663
 664         if (sk->sk_user_data) {
 665                 psock = ERR_PTR(-EBUSY);
 666                 goto out;
 667         }
 668
 669         psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
 670         if (!psock) {
 671                 psock = ERR_PTR(-ENOMEM);
 672                 goto out;
 673         }
 674
 675         prot = READ_ONCE(sk->sk_prot);
 676         psock->sk = sk;
 677         psock->eval = __SK_NONE;
 678         psock->sk_proto = prot;
 679         psock->saved_unhash = prot->unhash;
 680         psock->saved_close = prot->close;
 681         psock->saved_write_space = sk->sk_write_space;
 682
 683         INIT_LIST_HEAD(&psock->link);
 684         spin_lock_init(&psock->link_lock);
 685
 686         INIT_WORK(&psock->work, sk_psock_backlog);
 687         mutex_init(&psock->work_mutex);
 688         INIT_LIST_HEAD(&psock->ingress_msg);
 689         spin_lock_init(&psock->ingress_lock);
 690         skb_queue_head_init(&psock->ingress_skb);
 691
 692         sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
 693         refcount_set(&psock->refcnt, 1);
 694
 695         rcu_assign_sk_user_data_nocopy(sk, psock);
 696         sock_hold(sk);
 697
 698 out:
 699         write_unlock_bh(&sk->sk_callback_lock);
 700         return psock;
 701 }
 702 EXPORT_SYMBOL_GPL(sk_psock_init);
 703
 704 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
 705 {
 706         struct sk_psock_link *link;
 707
 708         spin_lock_bh(&psock->link_lock);
 709         link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
 710                                         list);
 711         if (link)
 712                 list_del(&link->list);
 713         spin_unlock_bh(&psock->link_lock);
 714         return link;
 715 }
 716
 717 static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
 718 {
 719         struct sk_msg *msg, *tmp;
 720
 721         list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
 722                 list_del(&msg->list);
 723                 sk_msg_free(psock->sk, msg);
 724                 kfree(msg);
 725         }
 726 }
 727
 728 static void __sk_psock_zap_ingress(struct sk_psock *psock)
 729 {
 730         struct sk_buff *skb;
 731
 732         while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
 733                 skb_bpf_redirect_clear(skb);
 734                 kfree_skb(skb);
 735         }
 736         __sk_psock_purge_ingress_msg(psock);
 737 }
 738
 739 static void sk_psock_link_destroy(struct sk_psock *psock)
 740 {
 741         struct sk_psock_link *link, *tmp;
 742
 743         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 744                 list_del(&link->list);
 745                 sk_psock_free_link(link);
 746         }
 747 }
 748
 749 void sk_psock_stop(struct sk_psock *psock, bool wait)
 750 {
 751         spin_lock_bh(&psock->ingress_lock);
 752         sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 753         sk_psock_cork_free(psock);
 754         __sk_psock_zap_ingress(psock);
 755         spin_unlock_bh(&psock->ingress_lock);
 756
 757         if (wait)
 758                 cancel_work_sync(&psock->work);
 759 }
 760
 761 static void sk_psock_done_strp(struct sk_psock *psock);
 762
 763 static void sk_psock_destroy(struct work_struct *work)
 764 {
 765         struct sk_psock *psock = container_of(to_rcu_work(work),
 766                                               struct sk_psock, rwork);
 767         /* No sk_callback_lock since already detached. */
 768
 769         sk_psock_done_strp(psock);
 770
 771         cancel_work_sync(&psock->work);
 772         mutex_destroy(&psock->work_mutex);
 773
 774         psock_progs_drop(&psock->progs);
 775
 776         sk_psock_link_destroy(psock);
 777         sk_psock_cork_free(psock);
 778
 779         if (psock->sk_redir)
 780                 sock_put(psock->sk_redir);
 781         sock_put(psock->sk);
 782         kfree(psock);
 783 }
 784
 785 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 786 {
 787         sk_psock_stop(psock, false);
 788
 789         write_lock_bh(&sk->sk_callback_lock);
 790         sk_psock_restore_proto(sk, psock);
 791         rcu_assign_sk_user_data(sk, NULL);
 792         if (psock->progs.stream_parser)
 793                 sk_psock_stop_strp(sk, psock);
 794         else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
 795                 sk_psock_stop_verdict(sk, psock);
 796         write_unlock_bh(&sk->sk_callback_lock);
 797
 798         INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
 799         queue_rcu_work(system_wq, &psock->rwork);
 800 }
 801 EXPORT_SYMBOL_GPL(sk_psock_drop);
 802
 803 static int sk_psock_map_verd(int verdict, bool redir)
 804 {
 805         switch (verdict) {
 806         case SK_PASS:
 807                 return redir ? __SK_REDIRECT : __SK_PASS;
 808         case SK_DROP:
 809         default:
 810                 break;
 811         }
 812
 813         return __SK_DROP;
 814 }
 815
 816 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 817                          struct sk_msg *msg)
 818 {
 819         struct bpf_prog *prog;
 820         int ret;
 821
 822         rcu_read_lock();
 823         prog = READ_ONCE(psock->progs.msg_parser);
 824         if (unlikely(!prog)) {
 825                 ret = __SK_PASS;
 826                 goto out;
 827         }
 828
 829         sk_msg_compute_data_pointers(msg);
 830         msg->sk = sk;
 831         ret = bpf_prog_run_pin_on_cpu(prog, msg);
 832         ret = sk_psock_map_verd(ret, msg->sk_redir);
 833         psock->apply_bytes = msg->apply_bytes;
 834         if (ret == __SK_REDIRECT) {
 835                 if (psock->sk_redir)
 836                         sock_put(psock->sk_redir);
 837                 psock->sk_redir = msg->sk_redir;
 838                 if (!psock->sk_redir) {
 839                         ret = __SK_DROP;
 840                         goto out;
 841                 }
 842                 sock_hold(psock->sk_redir);
 843         }
 844 out:
 845         rcu_read_unlock();
 846         return ret;
 847 }
 848 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
 849
 850 static void sk_psock_skb_redirect(struct sk_buff *skb)
 851 {
 852         struct sk_psock *psock_other;
 853         struct sock *sk_other;
 854
 855         sk_other = skb_bpf_redirect_fetch(skb);
 856         /* This error is a buggy BPF program, it returned a redirect
 857          * return code, but then didn't set a redirect interface.
 858          */
 859         if (unlikely(!sk_other)) {
 860                 kfree_skb(skb);
 861                 return;
 862         }
 863         psock_other = sk_psock(sk_other);
 864         /* This error indicates the socket is being torn down or had another
 865          * error that caused the pipe to break. We can't send a packet on
 866          * a socket that is in this state so we drop the skb.
 867          */
 868         if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
 869                 kfree_skb(skb);
 870                 return;
 871         }
 872         spin_lock_bh(&psock_other->ingress_lock);
 873         if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
 874                 spin_unlock_bh(&psock_other->ingress_lock);
 875                 kfree_skb(skb);
 876                 return;
 877         }
 878
 879         skb_queue_tail(&psock_other->ingress_skb, skb);
 880         schedule_work(&psock_other->work);
 881         spin_unlock_bh(&psock_other->ingress_lock);
 882 }
 883
 884 static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict)
 885 {
 886         switch (verdict) {
 887         case __SK_REDIRECT:
 888                 sk_psock_skb_redirect(skb);
 889                 break;
 890         case __SK_PASS:
 891         case __SK_DROP:
 892         default:
 893                 break;
 894         }
 895 }
 896
 897 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 898 {
 899         struct bpf_prog *prog;
 900         int ret = __SK_PASS;
 901
 902         rcu_read_lock();
 903         prog = READ_ONCE(psock->progs.stream_verdict);
 904         if (likely(prog)) {
 905                 skb->sk = psock->sk;
 906                 skb_dst_drop(skb);
 907                 skb_bpf_redirect_clear(skb);
 908                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 909                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 910                 skb->sk = NULL;
 911         }
 912         sk_psock_tls_verdict_apply(skb, psock->sk, ret);
 913         rcu_read_unlock();
 914         return ret;
 915 }
 916 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
 917
 918 static void sk_psock_verdict_apply(struct sk_psock *psock,
 919                                    struct sk_buff *skb, int verdict)
 920 {
 921         struct sock *sk_other;
 922         int err = -EIO;
 923
 924         switch (verdict) {
 925         case __SK_PASS:
 926                 sk_other = psock->sk;
 927                 if (sock_flag(sk_other, SOCK_DEAD) ||
 928                     !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 929                         goto out_free;
 930                 }
 931
 932                 skb_bpf_set_ingress(skb);
 933
 934                 /* If the queue is empty then we can submit directly
 935                  * into the msg queue. If its not empty we have to
 936                  * queue work otherwise we may get OOO data. Otherwise,
 937                  * if sk_psock_skb_ingress errors will be handled by
 938                  * retrying later from workqueue.
 939                  */
 940                 if (skb_queue_empty(&psock->ingress_skb)) {
 941                         err = sk_psock_skb_ingress_self(psock, skb);
 942                 }
 943                 if (err < 0) {
 944                         spin_lock_bh(&psock->ingress_lock);
 945                         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 946                                 skb_queue_tail(&psock->ingress_skb, skb);
 947                                 schedule_work(&psock->work);
 948                         }
 949                         spin_unlock_bh(&psock->ingress_lock);
 950                 }
 951                 break;
 952         case __SK_REDIRECT:
 953                 sk_psock_skb_redirect(skb);
 954                 break;
 955         case __SK_DROP:
 956         default:
 957 out_free:
 958                 kfree_skb(skb);
 959         }
 960 }
 961
 962 static void sk_psock_write_space(struct sock *sk)
 963 {
 964         struct sk_psock *psock;
 965         void (*write_space)(struct sock *sk) = NULL;
 966
 967         rcu_read_lock();
 968         psock = sk_psock(sk);
 969         if (likely(psock)) {
 970                 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 971                         schedule_work(&psock->work);
 972                 write_space = psock->saved_write_space;
 973         }
 974         rcu_read_unlock();
 975         if (write_space)
 976                 write_space(sk);
 977 }
 978
 979 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 980 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
 981 {
 982         struct sk_psock *psock;
 983         struct bpf_prog *prog;
 984         int ret = __SK_DROP;
 985         struct sock *sk;
 986
 987         rcu_read_lock();
 988         sk = strp->sk;
 989         psock = sk_psock(sk);
 990         if (unlikely(!psock)) {
 991                 kfree_skb(skb);
 992                 goto out;
 993         }
 994         prog = READ_ONCE(psock->progs.stream_verdict);
 995         if (likely(prog)) {
 996                 skb->sk = sk;
 997                 skb_dst_drop(skb);
 998                 skb_bpf_redirect_clear(skb);
 999                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1000                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1001                 skb->sk = NULL;
1002         }
1003         sk_psock_verdict_apply(psock, skb, ret);
1004 out:
1005         rcu_read_unlock();
1006 }
1007
1008 static int sk_psock_strp_read_done(struct strparser *strp, int err)
1009 {
1010         return err;
1011 }
1012
1013 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
1014 {
1015         struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1016         struct bpf_prog *prog;
1017         int ret = skb->len;
1018
1019         rcu_read_lock();
1020         prog = READ_ONCE(psock->progs.stream_parser);
1021         if (likely(prog)) {
1022                 skb->sk = psock->sk;
1023                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1024                 skb->sk = NULL;
1025         }
1026         rcu_read_unlock();
1027         return ret;
1028 }
1029
1030 /* Called with socket lock held. */
1031 static void sk_psock_strp_data_ready(struct sock *sk)
1032 {
1033         struct sk_psock *psock;
1034
1035         rcu_read_lock();
1036         psock = sk_psock(sk);
1037         if (likely(psock)) {
1038                 if (tls_sw_has_ctx_rx(sk)) {
1039                         psock->saved_data_ready(sk);
1040                 } else {
1041                         write_lock_bh(&sk->sk_callback_lock);
1042                         strp_data_ready(&psock->strp);
1043                         write_unlock_bh(&sk->sk_callback_lock);
1044                 }
1045         }
1046         rcu_read_unlock();
1047 }
1048
1049 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
1050 {
1051         static const struct strp_callbacks cb = {
1052                 .rcv_msg        = sk_psock_strp_read,
1053                 .read_sock_done = sk_psock_strp_read_done,
1054                 .parse_msg      = sk_psock_strp_parse,
1055         };
1056
1057         return strp_init(&psock->strp, sk, &cb);
1058 }
1059
1060 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
1061 {
1062         if (psock->saved_data_ready)
1063                 return;
1064
1065         psock->saved_data_ready = sk->sk_data_ready;
1066         sk->sk_data_ready = sk_psock_strp_data_ready;
1067         sk->sk_write_space = sk_psock_write_space;
1068 }
1069
1070 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
1071 {
1072         if (!psock->saved_data_ready)
1073                 return;
1074
1075         sk->sk_data_ready = psock->saved_data_ready;
1076         psock->saved_data_ready = NULL;
1077         strp_stop(&psock->strp);
1078 }
1079
1080 static void sk_psock_done_strp(struct sk_psock *psock)
1081 {
1082         /* Parser has been stopped */
1083         if (psock->progs.stream_parser)
1084                 strp_done(&psock->strp);
1085 }
1086 #else
1087 static void sk_psock_done_strp(struct sk_psock *psock)
1088 {
1089 }
1090 #endif /* CONFIG_BPF_STREAM_PARSER */
1091
1092 static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
1093                                  unsigned int offset, size_t orig_len)
1094 {
1095         struct sock *sk = (struct sock *)desc->arg.data;
1096         struct sk_psock *psock;
1097         struct bpf_prog *prog;
1098         int ret = __SK_DROP;
1099         int len = skb->len;
1100
1101         /* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */
1102         skb = skb_clone(skb, GFP_ATOMIC);
1103         if (!skb) {
1104                 desc->error = -ENOMEM;
1105                 return 0;
1106         }
1107
1108         rcu_read_lock();
1109         psock = sk_psock(sk);
1110         if (unlikely(!psock)) {
1111                 len = 0;
1112                 kfree_skb(skb);
1113                 goto out;
1114         }
1115         prog = READ_ONCE(psock->progs.stream_verdict);
1116         if (!prog)
1117                 prog = READ_ONCE(psock->progs.skb_verdict);
1118         if (likely(prog)) {
1119                 skb->sk = sk;
1120                 skb_dst_drop(skb);
1121                 skb_bpf_redirect_clear(skb);
1122                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1123                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1124                 skb->sk = NULL;
1125         }
1126         sk_psock_verdict_apply(psock, skb, ret);
1127 out:
1128         rcu_read_unlock();
1129         return len;
1130 }
1131
1132 static void sk_psock_verdict_data_ready(struct sock *sk)
1133 {
1134         struct socket *sock = sk->sk_socket;
1135         read_descriptor_t desc;
1136
1137         if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
1138                 return;
1139
1140         desc.arg.data = sk;
1141         desc.error = 0;
1142         desc.count = 1;
1143
1144         sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv);
1145 }
1146
1147 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1148 {
1149         if (psock->saved_data_ready)
1150                 return;
1151
1152         psock->saved_data_ready = sk->sk_data_ready;
1153         sk->sk_data_ready = sk_psock_verdict_data_ready;
1154         sk->sk_write_space = sk_psock_write_space;
1155 }
1156
1157 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1158 {
1159         if (!psock->saved_data_ready)
1160                 return;
1161
1162         sk->sk_data_ready = psock->saved_data_ready;
1163         psock->saved_data_ready = NULL;
1164 }