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         u32 osize = msg->sg.size;
  31         int ret = 0;
  32
  33         len -= msg->sg.size;
  34         while (len > 0) {
  35                 struct scatterlist *sge;
  36                 u32 orig_offset;
  37                 int use, i;
  38
  39                 if (!sk_page_frag_refill(sk, pfrag)) {
  40                         ret = -ENOMEM;
  41                         goto msg_trim;
  42                 }
  43
  44                 orig_offset = pfrag->offset;
  45                 use = min_t(int, len, pfrag->size - orig_offset);
  46                 if (!sk_wmem_schedule(sk, use)) {
  47                         ret = -ENOMEM;
  48                         goto msg_trim;
  49                 }
  50
  51                 i = msg->sg.end;
  52                 sk_msg_iter_var_prev(i);
  53                 sge = &msg->sg.data[i];
  54
  55                 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
  56                     sg_page(sge) == pfrag->page &&
  57                     sge->offset + sge->length == orig_offset) {
  58                         sge->length += use;
  59                 } else {
  60                         if (sk_msg_full(msg)) {
  61                                 ret = -ENOSPC;
  62                                 break;
  63                         }
  64
  65                         sge = &msg->sg.data[msg->sg.end];
  66                         sg_unmark_end(sge);
  67                         sg_set_page(sge, pfrag->page, use, orig_offset);
  68                         get_page(pfrag->page);
  69                         sk_msg_iter_next(msg, end);
  70                 }
  71
  72                 sk_mem_charge(sk, use);
  73                 msg->sg.size += use;
  74                 pfrag->offset += use;
  75                 len -= use;
  76         }
  77
  78         return ret;
  79
  80 msg_trim:
  81         sk_msg_trim(sk, msg, osize);
  82         return ret;
  83 }
  84 EXPORT_SYMBOL_GPL(sk_msg_alloc);
  85
  86 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
  87                  u32 off, u32 len)
  88 {
  89         int i = src->sg.start;
  90         struct scatterlist *sge = sk_msg_elem(src, i);
  91         struct scatterlist *sgd = NULL;
  92         u32 sge_len, sge_off;
  93
  94         while (off) {
  95                 if (sge->length > off)
  96                         break;
  97                 off -= sge->length;
  98                 sk_msg_iter_var_next(i);
  99                 if (i == src->sg.end && off)
 100                         return -ENOSPC;
 101                 sge = sk_msg_elem(src, i);
 102         }
 103
 104         while (len) {
 105                 sge_len = sge->length - off;
 106                 if (sge_len > len)
 107                         sge_len = len;
 108
 109                 if (dst->sg.end)
 110                         sgd = sk_msg_elem(dst, dst->sg.end - 1);
 111
 112                 if (sgd &&
 113                     (sg_page(sge) == sg_page(sgd)) &&
 114                     (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
 115                         sgd->length += sge_len;
 116                         dst->sg.size += sge_len;
 117                 } else if (!sk_msg_full(dst)) {
 118                         sge_off = sge->offset + off;
 119                         sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
 120                 } else {
 121                         return -ENOSPC;
 122                 }
 123
 124                 off = 0;
 125                 len -= sge_len;
 126                 sk_mem_charge(sk, sge_len);
 127                 sk_msg_iter_var_next(i);
 128                 if (i == src->sg.end && len)
 129                         return -ENOSPC;
 130                 sge = sk_msg_elem(src, i);
 131         }
 132
 133         return 0;
 134 }
 135 EXPORT_SYMBOL_GPL(sk_msg_clone);
 136
 137 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
 138 {
 139         int i = msg->sg.start;
 140
 141         do {
 142                 struct scatterlist *sge = sk_msg_elem(msg, i);
 143
 144                 if (bytes < sge->length) {
 145                         sge->length -= bytes;
 146                         sge->offset += bytes;
 147                         sk_mem_uncharge(sk, bytes);
 148                         break;
 149                 }
 150
 151                 sk_mem_uncharge(sk, sge->length);
 152                 bytes -= sge->length;
 153                 sge->length = 0;
 154                 sge->offset = 0;
 155                 sk_msg_iter_var_next(i);
 156         } while (bytes && i != msg->sg.end);
 157         msg->sg.start = i;
 158 }
 159 EXPORT_SYMBOL_GPL(sk_msg_return_zero);
 160
 161 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
 162 {
 163         int i = msg->sg.start;
 164
 165         do {
 166                 struct scatterlist *sge = &msg->sg.data[i];
 167                 int uncharge = (bytes < sge->length) ? bytes : sge->length;
 168
 169                 sk_mem_uncharge(sk, uncharge);
 170                 bytes -= uncharge;
 171                 sk_msg_iter_var_next(i);
 172         } while (i != msg->sg.end);
 173 }
 174 EXPORT_SYMBOL_GPL(sk_msg_return);
 175
 176 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
 177                             bool charge)
 178 {
 179         struct scatterlist *sge = sk_msg_elem(msg, i);
 180         u32 len = sge->length;
 181
 182         /* When the skb owns the memory we free it from consume_skb path. */
 183         if (!msg->skb) {
 184                 if (charge)
 185                         sk_mem_uncharge(sk, len);
 186                 put_page(sg_page(sge));
 187         }
 188         memset(sge, 0, sizeof(*sge));
 189         return len;
 190 }
 191
 192 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
 193                          bool charge)
 194 {
 195         struct scatterlist *sge = sk_msg_elem(msg, i);
 196         int freed = 0;
 197
 198         while (msg->sg.size) {
 199                 msg->sg.size -= sge->length;
 200                 freed += sk_msg_free_elem(sk, msg, i, charge);
 201                 sk_msg_iter_var_next(i);
 202                 sk_msg_check_to_free(msg, i, msg->sg.size);
 203                 sge = sk_msg_elem(msg, i);
 204         }
 205         consume_skb(msg->skb);
 206         sk_msg_init(msg);
 207         return freed;
 208 }
 209
 210 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
 211 {
 212         return __sk_msg_free(sk, msg, msg->sg.start, false);
 213 }
 214 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
 215
 216 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
 217 {
 218         return __sk_msg_free(sk, msg, msg->sg.start, true);
 219 }
 220 EXPORT_SYMBOL_GPL(sk_msg_free);
 221
 222 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
 223                                   u32 bytes, bool charge)
 224 {
 225         struct scatterlist *sge;
 226         u32 i = msg->sg.start;
 227
 228         while (bytes) {
 229                 sge = sk_msg_elem(msg, i);
 230                 if (!sge->length)
 231                         break;
 232                 if (bytes < sge->length) {
 233                         if (charge)
 234                                 sk_mem_uncharge(sk, bytes);
 235                         sge->length -= bytes;
 236                         sge->offset += bytes;
 237                         msg->sg.size -= bytes;
 238                         break;
 239                 }
 240
 241                 msg->sg.size -= sge->length;
 242                 bytes -= sge->length;
 243                 sk_msg_free_elem(sk, msg, i, charge);
 244                 sk_msg_iter_var_next(i);
 245                 sk_msg_check_to_free(msg, i, bytes);
 246         }
 247         msg->sg.start = i;
 248 }
 249
 250 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
 251 {
 252         __sk_msg_free_partial(sk, msg, bytes, true);
 253 }
 254 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
 255
 256 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 257                                   u32 bytes)
 258 {
 259         __sk_msg_free_partial(sk, msg, bytes, false);
 260 }
 261
 262 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
 263 {
 264         int trim = msg->sg.size - len;
 265         u32 i = msg->sg.end;
 266
 267         if (trim <= 0) {
 268                 WARN_ON(trim < 0);
 269                 return;
 270         }
 271
 272         sk_msg_iter_var_prev(i);
 273         msg->sg.size = len;
 274         while (msg->sg.data[i].length &&
 275                trim >= msg->sg.data[i].length) {
 276                 trim -= msg->sg.data[i].length;
 277                 sk_msg_free_elem(sk, msg, i, true);
 278                 sk_msg_iter_var_prev(i);
 279                 if (!trim)
 280                         goto out;
 281         }
 282
 283         msg->sg.data[i].length -= trim;
 284         sk_mem_uncharge(sk, trim);
 285         /* Adjust copybreak if it falls into the trimmed part of last buf */
 286         if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
 287                 msg->sg.copybreak = msg->sg.data[i].length;
 288 out:
 289         sk_msg_iter_var_next(i);
 290         msg->sg.end = i;
 291
 292         /* If we trim data a full sg elem before curr pointer update
 293          * copybreak and current so that any future copy operations
 294          * start at new copy location.
 295          * However trimed data that has not yet been used in a copy op
 296          * does not require an update.
 297          */
 298         if (!msg->sg.size) {
 299                 msg->sg.curr = msg->sg.start;
 300                 msg->sg.copybreak = 0;
 301         } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
 302                    sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
 303                 sk_msg_iter_var_prev(i);
 304                 msg->sg.curr = i;
 305                 msg->sg.copybreak = msg->sg.data[i].length;
 306         }
 307 }
 308 EXPORT_SYMBOL_GPL(sk_msg_trim);
 309
 310 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 311                               struct sk_msg *msg, u32 bytes)
 312 {
 313         int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
 314         const int to_max_pages = MAX_MSG_FRAGS;
 315         struct page *pages[MAX_MSG_FRAGS];
 316         ssize_t orig, copied, use, offset;
 317
 318         orig = msg->sg.size;
 319         while (bytes > 0) {
 320                 i = 0;
 321                 maxpages = to_max_pages - num_elems;
 322                 if (maxpages == 0) {
 323                         ret = -EFAULT;
 324                         goto out;
 325                 }
 326
 327                 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
 328                                             &offset);
 329                 if (copied <= 0) {
 330                         ret = -EFAULT;
 331                         goto out;
 332                 }
 333
 334                 iov_iter_advance(from, copied);
 335                 bytes -= copied;
 336                 msg->sg.size += copied;
 337
 338                 while (copied) {
 339                         use = min_t(int, copied, PAGE_SIZE - offset);
 340                         sg_set_page(&msg->sg.data[msg->sg.end],
 341                                     pages[i], use, offset);
 342                         sg_unmark_end(&msg->sg.data[msg->sg.end]);
 343                         sk_mem_charge(sk, use);
 344
 345                         offset = 0;
 346                         copied -= use;
 347                         sk_msg_iter_next(msg, end);
 348                         num_elems++;
 349                         i++;
 350                 }
 351                 /* When zerocopy is mixed with sk_msg_*copy* operations we
 352                  * may have a copybreak set in this case clear and prefer
 353                  * zerocopy remainder when possible.
 354                  */
 355                 msg->sg.copybreak = 0;
 356                 msg->sg.curr = msg->sg.end;
 357         }
 358 out:
 359         /* Revert iov_iter updates, msg will need to use 'trim' later if it
 360          * also needs to be cleared.
 361          */
 362         if (ret)
 363                 iov_iter_revert(from, msg->sg.size - orig);
 364         return ret;
 365 }
 366 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
 367
 368 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 369                              struct sk_msg *msg, u32 bytes)
 370 {
 371         int ret = -ENOSPC, i = msg->sg.curr;
 372         struct scatterlist *sge;
 373         u32 copy, buf_size;
 374         void *to;
 375
 376         do {
 377                 sge = sk_msg_elem(msg, i);
 378                 /* This is possible if a trim operation shrunk the buffer */
 379                 if (msg->sg.copybreak >= sge->length) {
 380                         msg->sg.copybreak = 0;
 381                         sk_msg_iter_var_next(i);
 382                         if (i == msg->sg.end)
 383                                 break;
 384                         sge = sk_msg_elem(msg, i);
 385                 }
 386
 387                 buf_size = sge->length - msg->sg.copybreak;
 388                 copy = (buf_size > bytes) ? bytes : buf_size;
 389                 to = sg_virt(sge) + msg->sg.copybreak;
 390                 msg->sg.copybreak += copy;
 391                 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
 392                         ret = copy_from_iter_nocache(to, copy, from);
 393                 else
 394                         ret = copy_from_iter(to, copy, from);
 395                 if (ret != copy) {
 396                         ret = -EFAULT;
 397                         goto out;
 398                 }
 399                 bytes -= copy;
 400                 if (!bytes)
 401                         break;
 402                 msg->sg.copybreak = 0;
 403                 sk_msg_iter_var_next(i);
 404         } while (i != msg->sg.end);
 405 out:
 406         msg->sg.curr = i;
 407         return ret;
 408 }
 409 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
 410
 411 /* Receive sk_msg from psock->ingress_msg to @msg. */
 412 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 413                    int len, int flags)
 414 {
 415         struct iov_iter *iter = &msg->msg_iter;
 416         int peek = flags & MSG_PEEK;
 417         struct sk_msg *msg_rx;
 418         int i, copied = 0;
 419
 420         msg_rx = sk_psock_peek_msg(psock);
 421         while (copied != len) {
 422                 struct scatterlist *sge;
 423
 424                 if (unlikely(!msg_rx))
 425                         break;
 426
 427                 i = msg_rx->sg.start;
 428                 do {
 429                         struct page *page;
 430                         int copy;
 431
 432                         sge = sk_msg_elem(msg_rx, i);
 433                         copy = sge->length;
 434                         page = sg_page(sge);
 435                         if (copied + copy > len)
 436                                 copy = len - copied;
 437                         copy = copy_page_to_iter(page, sge->offset, copy, iter);
 438                         if (!copy)
 439                                 return copied ? copied : -EFAULT;
 440
 441                         copied += copy;
 442                         if (likely(!peek)) {
 443                                 sge->offset += copy;
 444                                 sge->length -= copy;
 445                                 if (!msg_rx->skb)
 446                                         sk_mem_uncharge(sk, copy);
 447                                 msg_rx->sg.size -= copy;
 448
 449                                 if (!sge->length) {
 450                                         sk_msg_iter_var_next(i);
 451                                         if (!msg_rx->skb)
 452                                                 put_page(page);
 453                                 }
 454                         } else {
 455                                 /* Lets not optimize peek case if copy_page_to_iter
 456                                  * didn't copy the entire length lets just break.
 457                                  */
 458                                 if (copy != sge->length)
 459                                         return copied;
 460                                 sk_msg_iter_var_next(i);
 461                         }
 462
 463                         if (copied == len)
 464                                 break;
 465                 } while (i != msg_rx->sg.end);
 466
 467                 if (unlikely(peek)) {
 468                         msg_rx = sk_psock_next_msg(psock, msg_rx);
 469                         if (!msg_rx)
 470                                 break;
 471                         continue;
 472                 }
 473
 474                 msg_rx->sg.start = i;
 475                 if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
 476                         msg_rx = sk_psock_dequeue_msg(psock);
 477                         kfree_sk_msg(msg_rx);
 478                 }
 479                 msg_rx = sk_psock_peek_msg(psock);
 480         }
 481
 482         return copied;
 483 }
 484 EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
 485
 486 bool sk_msg_is_readable(struct sock *sk)
 487 {
 488         struct sk_psock *psock;
 489         bool empty = true;
 490
 491         rcu_read_lock();
 492         psock = sk_psock(sk);
 493         if (likely(psock))
 494                 empty = list_empty(&psock->ingress_msg);
 495         rcu_read_unlock();
 496         return !empty;
 497 }
 498 EXPORT_SYMBOL_GPL(sk_msg_is_readable);
 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                                         u32 off, u32 len,
 521                                         struct sk_psock *psock,
 522                                         struct sock *sk,
 523                                         struct sk_msg *msg)
 524 {
 525         int num_sge, copied;
 526
 527         num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
 528         if (num_sge < 0) {
 529                 /* skb linearize may fail with ENOMEM, but lets simply try again
 530                  * later if this happens. Under memory pressure we don't want to
 531                  * drop the skb. We need to linearize the skb so that the mapping
 532                  * in skb_to_sgvec can not error.
 533                  */
 534                 if (skb_linearize(skb))
 535                         return -EAGAIN;
 536
 537                 num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
 538                 if (unlikely(num_sge < 0))
 539                         return num_sge;
 540         }
 541
 542         copied = len;
 543         msg->sg.start = 0;
 544         msg->sg.size = copied;
 545         msg->sg.end = num_sge;
 546         msg->skb = skb;
 547
 548         sk_psock_queue_msg(psock, msg);
 549         sk_psock_data_ready(sk, psock);
 550         return copied;
 551 }
 552
 553 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
 554                                      u32 off, u32 len);
 555
 556 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
 557                                 u32 off, u32 len)
 558 {
 559         struct sock *sk = psock->sk;
 560         struct sk_msg *msg;
 561         int err;
 562
 563         /* If we are receiving on the same sock skb->sk is already assigned,
 564          * skip memory accounting and owner transition seeing it already set
 565          * correctly.
 566          */
 567         if (unlikely(skb->sk == sk))
 568                 return sk_psock_skb_ingress_self(psock, skb, off, len);
 569         msg = sk_psock_create_ingress_msg(sk, skb);
 570         if (!msg)
 571                 return -EAGAIN;
 572
 573         /* This will transition ownership of the data from the socket where
 574          * the BPF program was run initiating the redirect to the socket
 575          * we will eventually receive this data on. The data will be released
 576          * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
 577          * into user buffers.
 578          */
 579         skb_set_owner_r(skb, sk);
 580         err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 581         if (err < 0)
 582                 kfree(msg);
 583         return err;
 584 }
 585
 586 /* Puts an skb on the ingress queue of the socket already assigned to the
 587  * skb. In this case we do not need to check memory limits or skb_set_owner_r
 588  * because the skb is already accounted for here.
 589  */
 590 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
 591                                      u32 off, u32 len)
 592 {
 593         struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
 594         struct sock *sk = psock->sk;
 595         int err;
 596
 597         if (unlikely(!msg))
 598                 return -EAGAIN;
 599         sk_msg_init(msg);
 600         skb_set_owner_r(skb, sk);
 601         err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 602         if (err < 0)
 603                 kfree(msg);
 604         return err;
 605 }
 606
 607 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 608                                u32 off, u32 len, bool ingress)
 609 {
 610         if (!ingress) {
 611                 if (!sock_writeable(psock->sk))
 612                         return -EAGAIN;
 613                 return skb_send_sock(psock->sk, skb, off, len);
 614         }
 615         return sk_psock_skb_ingress(psock, skb, off, len);
 616 }
 617
 618 static void sk_psock_skb_state(struct sk_psock *psock,
 619                                struct sk_psock_work_state *state,
 620                                struct sk_buff *skb,
 621                                int len, int off)
 622 {
 623         spin_lock_bh(&psock->ingress_lock);
 624         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 625                 state->skb = skb;
 626                 state->len = len;
 627                 state->off = off;
 628         } else {
 629                 sock_drop(psock->sk, skb);
 630         }
 631         spin_unlock_bh(&psock->ingress_lock);
 632 }
 633
 634 static void sk_psock_backlog(struct work_struct *work)
 635 {
 636         struct sk_psock *psock = container_of(work, struct sk_psock, work);
 637         struct sk_psock_work_state *state = &psock->work_state;
 638         struct sk_buff *skb = NULL;
 639         bool ingress;
 640         u32 len, off;
 641         int ret;
 642
 643         mutex_lock(&psock->work_mutex);
 644         if (unlikely(state->skb)) {
 645                 spin_lock_bh(&psock->ingress_lock);
 646                 skb = state->skb;
 647                 len = state->len;
 648                 off = state->off;
 649                 state->skb = NULL;
 650                 spin_unlock_bh(&psock->ingress_lock);
 651         }
 652         if (skb)
 653                 goto start;
 654
 655         while ((skb = skb_dequeue(&psock->ingress_skb))) {
 656                 len = skb->len;
 657                 off = 0;
 658                 if (skb_bpf_strparser(skb)) {
 659                         struct strp_msg *stm = strp_msg(skb);
 660
 661                         off = stm->offset;
 662                         len = stm->full_len;
 663                 }
 664 start:
 665                 ingress = skb_bpf_ingress(skb);
 666                 skb_bpf_redirect_clear(skb);
 667                 do {
 668                         ret = -EIO;
 669                         if (!sock_flag(psock->sk, SOCK_DEAD))
 670                                 ret = sk_psock_handle_skb(psock, skb, off,
 671                                                           len, ingress);
 672                         if (ret <= 0) {
 673                                 if (ret == -EAGAIN) {
 674                                         sk_psock_skb_state(psock, state, skb,
 675                                                            len, off);
 676                                         goto end;
 677                                 }
 678                                 /* Hard errors break pipe and stop xmit. */
 679                                 sk_psock_report_error(psock, ret ? -ret : EPIPE);
 680                                 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 681                                 sock_drop(psock->sk, skb);
 682                                 goto end;
 683                         }
 684                         off += ret;
 685                         len -= ret;
 686                 } while (len);
 687
 688                 if (!ingress)
 689                         kfree_skb(skb);
 690         }
 691 end:
 692         mutex_unlock(&psock->work_mutex);
 693 }
 694
 695 struct sk_psock *sk_psock_init(struct sock *sk, int node)
 696 {
 697         struct sk_psock *psock;
 698         struct proto *prot;
 699
 700         write_lock_bh(&sk->sk_callback_lock);
 701
 702         if (sk_is_inet(sk) && inet_csk_has_ulp(sk)) {
 703                 psock = ERR_PTR(-EINVAL);
 704                 goto out;
 705         }
 706
 707         if (sk->sk_user_data) {
 708                 psock = ERR_PTR(-EBUSY);
 709                 goto out;
 710         }
 711
 712         psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
 713         if (!psock) {
 714                 psock = ERR_PTR(-ENOMEM);
 715                 goto out;
 716         }
 717
 718         prot = READ_ONCE(sk->sk_prot);
 719         psock->sk = sk;
 720         psock->eval = __SK_NONE;
 721         psock->sk_proto = prot;
 722         psock->saved_unhash = prot->unhash;
 723         psock->saved_close = prot->close;
 724         psock->saved_write_space = sk->sk_write_space;
 725
 726         INIT_LIST_HEAD(&psock->link);
 727         spin_lock_init(&psock->link_lock);
 728
 729         INIT_WORK(&psock->work, sk_psock_backlog);
 730         mutex_init(&psock->work_mutex);
 731         INIT_LIST_HEAD(&psock->ingress_msg);
 732         spin_lock_init(&psock->ingress_lock);
 733         skb_queue_head_init(&psock->ingress_skb);
 734
 735         sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
 736         refcount_set(&psock->refcnt, 1);
 737
 738         rcu_assign_sk_user_data_nocopy(sk, psock);
 739         sock_hold(sk);
 740
 741 out:
 742         write_unlock_bh(&sk->sk_callback_lock);
 743         return psock;
 744 }
 745 EXPORT_SYMBOL_GPL(sk_psock_init);
 746
 747 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
 748 {
 749         struct sk_psock_link *link;
 750
 751         spin_lock_bh(&psock->link_lock);
 752         link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
 753                                         list);
 754         if (link)
 755                 list_del(&link->list);
 756         spin_unlock_bh(&psock->link_lock);
 757         return link;
 758 }
 759
 760 static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
 761 {
 762         struct sk_msg *msg, *tmp;
 763
 764         list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
 765                 list_del(&msg->list);
 766                 sk_msg_free(psock->sk, msg);
 767                 kfree(msg);
 768         }
 769 }
 770
 771 static void __sk_psock_zap_ingress(struct sk_psock *psock)
 772 {
 773         struct sk_buff *skb;
 774
 775         while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
 776                 skb_bpf_redirect_clear(skb);
 777                 sock_drop(psock->sk, skb);
 778         }
 779         kfree_skb(psock->work_state.skb);
 780         /* We null the skb here to ensure that calls to sk_psock_backlog
 781          * do not pick up the free'd skb.
 782          */
 783         psock->work_state.skb = NULL;
 784         __sk_psock_purge_ingress_msg(psock);
 785 }
 786
 787 static void sk_psock_link_destroy(struct sk_psock *psock)
 788 {
 789         struct sk_psock_link *link, *tmp;
 790
 791         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 792                 list_del(&link->list);
 793                 sk_psock_free_link(link);
 794         }
 795 }
 796
 797 void sk_psock_stop(struct sk_psock *psock, bool wait)
 798 {
 799         spin_lock_bh(&psock->ingress_lock);
 800         sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 801         sk_psock_cork_free(psock);
 802         __sk_psock_zap_ingress(psock);
 803         spin_unlock_bh(&psock->ingress_lock);
 804
 805         if (wait)
 806                 cancel_work_sync(&psock->work);
 807 }
 808
 809 static void sk_psock_done_strp(struct sk_psock *psock);
 810
 811 static void sk_psock_destroy(struct work_struct *work)
 812 {
 813         struct sk_psock *psock = container_of(to_rcu_work(work),
 814                                               struct sk_psock, rwork);
 815         /* No sk_callback_lock since already detached. */
 816
 817         sk_psock_done_strp(psock);
 818
 819         cancel_work_sync(&psock->work);
 820         mutex_destroy(&psock->work_mutex);
 821
 822         psock_progs_drop(&psock->progs);
 823
 824         sk_psock_link_destroy(psock);
 825         sk_psock_cork_free(psock);
 826
 827         if (psock->sk_redir)
 828                 sock_put(psock->sk_redir);
 829         sock_put(psock->sk);
 830         kfree(psock);
 831 }
 832
 833 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 834 {
 835         write_lock_bh(&sk->sk_callback_lock);
 836         sk_psock_restore_proto(sk, psock);
 837         rcu_assign_sk_user_data(sk, NULL);
 838         if (psock->progs.stream_parser)
 839                 sk_psock_stop_strp(sk, psock);
 840         else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
 841                 sk_psock_stop_verdict(sk, psock);
 842         write_unlock_bh(&sk->sk_callback_lock);
 843
 844         sk_psock_stop(psock, false);
 845
 846         INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
 847         queue_rcu_work(system_wq, &psock->rwork);
 848 }
 849 EXPORT_SYMBOL_GPL(sk_psock_drop);
 850
 851 static int sk_psock_map_verd(int verdict, bool redir)
 852 {
 853         switch (verdict) {
 854         case SK_PASS:
 855                 return redir ? __SK_REDIRECT : __SK_PASS;
 856         case SK_DROP:
 857         default:
 858                 break;
 859         }
 860
 861         return __SK_DROP;
 862 }
 863
 864 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 865                          struct sk_msg *msg)
 866 {
 867         struct bpf_prog *prog;
 868         int ret;
 869
 870         rcu_read_lock();
 871         prog = READ_ONCE(psock->progs.msg_parser);
 872         if (unlikely(!prog)) {
 873                 ret = __SK_PASS;
 874                 goto out;
 875         }
 876
 877         sk_msg_compute_data_pointers(msg);
 878         msg->sk = sk;
 879         ret = bpf_prog_run_pin_on_cpu(prog, msg);
 880         ret = sk_psock_map_verd(ret, msg->sk_redir);
 881         psock->apply_bytes = msg->apply_bytes;
 882         if (ret == __SK_REDIRECT) {
 883                 if (psock->sk_redir)
 884                         sock_put(psock->sk_redir);
 885                 psock->sk_redir = msg->sk_redir;
 886                 if (!psock->sk_redir) {
 887                         ret = __SK_DROP;
 888                         goto out;
 889                 }
 890                 sock_hold(psock->sk_redir);
 891         }
 892 out:
 893         rcu_read_unlock();
 894         return ret;
 895 }
 896 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
 897
 898 static int sk_psock_skb_redirect(struct sk_psock *from, struct sk_buff *skb)
 899 {
 900         struct sk_psock *psock_other;
 901         struct sock *sk_other;
 902
 903         sk_other = skb_bpf_redirect_fetch(skb);
 904         /* This error is a buggy BPF program, it returned a redirect
 905          * return code, but then didn't set a redirect interface.
 906          */
 907         if (unlikely(!sk_other)) {
 908                 skb_bpf_redirect_clear(skb);
 909                 sock_drop(from->sk, skb);
 910                 return -EIO;
 911         }
 912         psock_other = sk_psock(sk_other);
 913         /* This error indicates the socket is being torn down or had another
 914          * error that caused the pipe to break. We can't send a packet on
 915          * a socket that is in this state so we drop the skb.
 916          */
 917         if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
 918                 skb_bpf_redirect_clear(skb);
 919                 sock_drop(from->sk, skb);
 920                 return -EIO;
 921         }
 922         spin_lock_bh(&psock_other->ingress_lock);
 923         if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
 924                 spin_unlock_bh(&psock_other->ingress_lock);
 925                 skb_bpf_redirect_clear(skb);
 926                 sock_drop(from->sk, skb);
 927                 return -EIO;
 928         }
 929
 930         skb_queue_tail(&psock_other->ingress_skb, skb);
 931         schedule_work(&psock_other->work);
 932         spin_unlock_bh(&psock_other->ingress_lock);
 933         return 0;
 934 }
 935
 936 static void sk_psock_tls_verdict_apply(struct sk_buff *skb,
 937                                        struct sk_psock *from, int verdict)
 938 {
 939         switch (verdict) {
 940         case __SK_REDIRECT:
 941                 sk_psock_skb_redirect(from, skb);
 942                 break;
 943         case __SK_PASS:
 944         case __SK_DROP:
 945         default:
 946                 break;
 947         }
 948 }
 949
 950 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 951 {
 952         struct bpf_prog *prog;
 953         int ret = __SK_PASS;
 954
 955         rcu_read_lock();
 956         prog = READ_ONCE(psock->progs.stream_verdict);
 957         if (likely(prog)) {
 958                 skb->sk = psock->sk;
 959                 skb_dst_drop(skb);
 960                 skb_bpf_redirect_clear(skb);
 961                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 962                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 963                 skb->sk = NULL;
 964         }
 965         sk_psock_tls_verdict_apply(skb, psock, ret);
 966         rcu_read_unlock();
 967         return ret;
 968 }
 969 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
 970
 971 static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
 972                                   int verdict)
 973 {
 974         struct sock *sk_other;
 975         int err = 0;
 976         u32 len, off;
 977
 978         switch (verdict) {
 979         case __SK_PASS:
 980                 err = -EIO;
 981                 sk_other = psock->sk;
 982                 if (sock_flag(sk_other, SOCK_DEAD) ||
 983                     !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 984                         skb_bpf_redirect_clear(skb);
 985                         goto out_free;
 986                 }
 987
 988                 skb_bpf_set_ingress(skb);
 989
 990                 /* If the queue is empty then we can submit directly
 991                  * into the msg queue. If its not empty we have to
 992                  * queue work otherwise we may get OOO data. Otherwise,
 993                  * if sk_psock_skb_ingress errors will be handled by
 994                  * retrying later from workqueue.
 995                  */
 996                 if (skb_queue_empty(&psock->ingress_skb)) {
 997                         len = skb->len;
 998                         off = 0;
 999                         if (skb_bpf_strparser(skb)) {
1000                                 struct strp_msg *stm = strp_msg(skb);
1001
1002                                 off = stm->offset;
1003                                 len = stm->full_len;
1004                         }
1005                         err = sk_psock_skb_ingress_self(psock, skb, off, len);
1006                 }
1007                 if (err < 0) {
1008                         spin_lock_bh(&psock->ingress_lock);
1009                         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
1010                                 skb_queue_tail(&psock->ingress_skb, skb);
1011                                 schedule_work(&psock->work);
1012                                 err = 0;
1013                         }
1014                         spin_unlock_bh(&psock->ingress_lock);
1015                         if (err < 0) {
1016                                 skb_bpf_redirect_clear(skb);
1017                                 goto out_free;
1018                         }
1019                 }
1020                 break;
1021         case __SK_REDIRECT:
1022                 err = sk_psock_skb_redirect(psock, skb);
1023                 break;
1024         case __SK_DROP:
1025         default:
1026 out_free:
1027                 sock_drop(psock->sk, skb);
1028         }
1029
1030         return err;
1031 }
1032
1033 static void sk_psock_write_space(struct sock *sk)
1034 {
1035         struct sk_psock *psock;
1036         void (*write_space)(struct sock *sk) = NULL;
1037
1038         rcu_read_lock();
1039         psock = sk_psock(sk);
1040         if (likely(psock)) {
1041                 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
1042                         schedule_work(&psock->work);
1043                 write_space = psock->saved_write_space;
1044         }
1045         rcu_read_unlock();
1046         if (write_space)
1047                 write_space(sk);
1048 }
1049
1050 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1051 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
1052 {
1053         struct sk_psock *psock;
1054         struct bpf_prog *prog;
1055         int ret = __SK_DROP;
1056         struct sock *sk;
1057
1058         rcu_read_lock();
1059         sk = strp->sk;
1060         psock = sk_psock(sk);
1061         if (unlikely(!psock)) {
1062                 sock_drop(sk, skb);
1063                 goto out;
1064         }
1065         prog = READ_ONCE(psock->progs.stream_verdict);
1066         if (likely(prog)) {
1067                 skb->sk = sk;
1068                 skb_dst_drop(skb);
1069                 skb_bpf_redirect_clear(skb);
1070                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1071                 if (ret == SK_PASS)
1072                         skb_bpf_set_strparser(skb);
1073                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1074                 skb->sk = NULL;
1075         }
1076         sk_psock_verdict_apply(psock, skb, ret);
1077 out:
1078         rcu_read_unlock();
1079 }
1080
1081 static int sk_psock_strp_read_done(struct strparser *strp, int err)
1082 {
1083         return err;
1084 }
1085
1086 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
1087 {
1088         struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1089         struct bpf_prog *prog;
1090         int ret = skb->len;
1091
1092         rcu_read_lock();
1093         prog = READ_ONCE(psock->progs.stream_parser);
1094         if (likely(prog)) {
1095                 skb->sk = psock->sk;
1096                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1097                 skb->sk = NULL;
1098         }
1099         rcu_read_unlock();
1100         return ret;
1101 }
1102
1103 /* Called with socket lock held. */
1104 static void sk_psock_strp_data_ready(struct sock *sk)
1105 {
1106         struct sk_psock *psock;
1107
1108         rcu_read_lock();
1109         psock = sk_psock(sk);
1110         if (likely(psock)) {
1111                 if (tls_sw_has_ctx_rx(sk)) {
1112                         psock->saved_data_ready(sk);
1113                 } else {
1114                         write_lock_bh(&sk->sk_callback_lock);
1115                         strp_data_ready(&psock->strp);
1116                         write_unlock_bh(&sk->sk_callback_lock);
1117                 }
1118         }
1119         rcu_read_unlock();
1120 }
1121
1122 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
1123 {
1124         static const struct strp_callbacks cb = {
1125                 .rcv_msg        = sk_psock_strp_read,
1126                 .read_sock_done = sk_psock_strp_read_done,
1127                 .parse_msg      = sk_psock_strp_parse,
1128         };
1129
1130         return strp_init(&psock->strp, sk, &cb);
1131 }
1132
1133 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
1134 {
1135         if (psock->saved_data_ready)
1136                 return;
1137
1138         psock->saved_data_ready = sk->sk_data_ready;
1139         sk->sk_data_ready = sk_psock_strp_data_ready;
1140         sk->sk_write_space = sk_psock_write_space;
1141 }
1142
1143 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
1144 {
1145         psock_set_prog(&psock->progs.stream_parser, NULL);
1146
1147         if (!psock->saved_data_ready)
1148                 return;
1149
1150         sk->sk_data_ready = psock->saved_data_ready;
1151         psock->saved_data_ready = NULL;
1152         strp_stop(&psock->strp);
1153 }
1154
1155 static void sk_psock_done_strp(struct sk_psock *psock)
1156 {
1157         /* Parser has been stopped */
1158         if (psock->progs.stream_parser)
1159                 strp_done(&psock->strp);
1160 }
1161 #else
1162 static void sk_psock_done_strp(struct sk_psock *psock)
1163 {
1164 }
1165 #endif /* CONFIG_BPF_STREAM_PARSER */
1166
1167 static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
1168                                  unsigned int offset, size_t orig_len)
1169 {
1170         struct sock *sk = (struct sock *)desc->arg.data;
1171         struct sk_psock *psock;
1172         struct bpf_prog *prog;
1173         int ret = __SK_DROP;
1174         int len = orig_len;
1175
1176         /* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */
1177         skb = skb_clone(skb, GFP_ATOMIC);
1178         if (!skb) {
1179                 desc->error = -ENOMEM;
1180                 return 0;
1181         }
1182
1183         rcu_read_lock();
1184         psock = sk_psock(sk);
1185         if (unlikely(!psock)) {
1186                 len = 0;
1187                 sock_drop(sk, skb);
1188                 goto out;
1189         }
1190         prog = READ_ONCE(psock->progs.stream_verdict);
1191         if (!prog)
1192                 prog = READ_ONCE(psock->progs.skb_verdict);
1193         if (likely(prog)) {
1194                 skb->sk = sk;
1195                 skb_dst_drop(skb);
1196                 skb_bpf_redirect_clear(skb);
1197                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1198                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1199                 skb->sk = NULL;
1200         }
1201         if (sk_psock_verdict_apply(psock, skb, ret) < 0)
1202                 len = 0;
1203 out:
1204         rcu_read_unlock();
1205         return len;
1206 }
1207
1208 static void sk_psock_verdict_data_ready(struct sock *sk)
1209 {
1210         struct socket *sock = sk->sk_socket;
1211         read_descriptor_t desc;
1212
1213         if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
1214                 return;
1215
1216         desc.arg.data = sk;
1217         desc.error = 0;
1218         desc.count = 1;
1219
1220         sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv);
1221 }
1222
1223 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1224 {
1225         if (psock->saved_data_ready)
1226                 return;
1227
1228         psock->saved_data_ready = sk->sk_data_ready;
1229         sk->sk_data_ready = sk_psock_verdict_data_ready;
1230         sk->sk_write_space = sk_psock_write_space;
1231 }
1232
1233 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1234 {
1235         psock_set_prog(&psock->progs.stream_verdict, NULL);
1236         psock_set_prog(&psock->progs.skb_verdict, NULL);
1237
1238         if (!psock->saved_data_ready)
1239                 return;
1240
1241         sk->sk_data_ready = psock->saved_data_ready;
1242         psock->saved_data_ready = NULL;
1243 }