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 #include <trace/events/sock.h>
  12
  13 static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
  14 {
  15         if (msg->sg.end > msg->sg.start &&
  16             elem_first_coalesce < msg->sg.end)
  17                 return true;
  18
  19         if (msg->sg.end < msg->sg.start &&
  20             (elem_first_coalesce > msg->sg.start ||
  21              elem_first_coalesce < msg->sg.end))
  22                 return true;
  23
  24         return false;
  25 }
  26
  27 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
  28                  int elem_first_coalesce)
  29 {
  30         struct page_frag *pfrag = sk_page_frag(sk);
  31         u32 osize = msg->sg.size;
  32         int ret = 0;
  33
  34         len -= msg->sg.size;
  35         while (len > 0) {
  36                 struct scatterlist *sge;
  37                 u32 orig_offset;
  38                 int use, i;
  39
  40                 if (!sk_page_frag_refill(sk, pfrag)) {
  41                         ret = -ENOMEM;
  42                         goto msg_trim;
  43                 }
  44
  45                 orig_offset = pfrag->offset;
  46                 use = min_t(int, len, pfrag->size - orig_offset);
  47                 if (!sk_wmem_schedule(sk, use)) {
  48                         ret = -ENOMEM;
  49                         goto msg_trim;
  50                 }
  51
  52                 i = msg->sg.end;
  53                 sk_msg_iter_var_prev(i);
  54                 sge = &msg->sg.data[i];
  55
  56                 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
  57                     sg_page(sge) == pfrag->page &&
  58                     sge->offset + sge->length == orig_offset) {
  59                         sge->length += use;
  60                 } else {
  61                         if (sk_msg_full(msg)) {
  62                                 ret = -ENOSPC;
  63                                 break;
  64                         }
  65
  66                         sge = &msg->sg.data[msg->sg.end];
  67                         sg_unmark_end(sge);
  68                         sg_set_page(sge, pfrag->page, use, orig_offset);
  69                         get_page(pfrag->page);
  70                         sk_msg_iter_next(msg, end);
  71                 }
  72
  73                 sk_mem_charge(sk, use);
  74                 msg->sg.size += use;
  75                 pfrag->offset += use;
  76                 len -= use;
  77         }
  78
  79         return ret;
  80
  81 msg_trim:
  82         sk_msg_trim(sk, msg, osize);
  83         return ret;
  84 }
  85 EXPORT_SYMBOL_GPL(sk_msg_alloc);
  86
  87 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
  88                  u32 off, u32 len)
  89 {
  90         int i = src->sg.start;
  91         struct scatterlist *sge = sk_msg_elem(src, i);
  92         struct scatterlist *sgd = NULL;
  93         u32 sge_len, sge_off;
  94
  95         while (off) {
  96                 if (sge->length > off)
  97                         break;
  98                 off -= sge->length;
  99                 sk_msg_iter_var_next(i);
 100                 if (i == src->sg.end && off)
 101                         return -ENOSPC;
 102                 sge = sk_msg_elem(src, i);
 103         }
 104
 105         while (len) {
 106                 sge_len = sge->length - off;
 107                 if (sge_len > len)
 108                         sge_len = len;
 109
 110                 if (dst->sg.end)
 111                         sgd = sk_msg_elem(dst, dst->sg.end - 1);
 112
 113                 if (sgd &&
 114                     (sg_page(sge) == sg_page(sgd)) &&
 115                     (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
 116                         sgd->length += sge_len;
 117                         dst->sg.size += sge_len;
 118                 } else if (!sk_msg_full(dst)) {
 119                         sge_off = sge->offset + off;
 120                         sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
 121                 } else {
 122                         return -ENOSPC;
 123                 }
 124
 125                 off = 0;
 126                 len -= sge_len;
 127                 sk_mem_charge(sk, sge_len);
 128                 sk_msg_iter_var_next(i);
 129                 if (i == src->sg.end && len)
 130                         return -ENOSPC;
 131                 sge = sk_msg_elem(src, i);
 132         }
 133
 134         return 0;
 135 }
 136 EXPORT_SYMBOL_GPL(sk_msg_clone);
 137
 138 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
 139 {
 140         int i = msg->sg.start;
 141
 142         do {
 143                 struct scatterlist *sge = sk_msg_elem(msg, i);
 144
 145                 if (bytes < sge->length) {
 146                         sge->length -= bytes;
 147                         sge->offset += bytes;
 148                         sk_mem_uncharge(sk, bytes);
 149                         break;
 150                 }
 151
 152                 sk_mem_uncharge(sk, sge->length);
 153                 bytes -= sge->length;
 154                 sge->length = 0;
 155                 sge->offset = 0;
 156                 sk_msg_iter_var_next(i);
 157         } while (bytes && i != msg->sg.end);
 158         msg->sg.start = i;
 159 }
 160 EXPORT_SYMBOL_GPL(sk_msg_return_zero);
 161
 162 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
 163 {
 164         int i = msg->sg.start;
 165
 166         do {
 167                 struct scatterlist *sge = &msg->sg.data[i];
 168                 int uncharge = (bytes < sge->length) ? bytes : sge->length;
 169
 170                 sk_mem_uncharge(sk, uncharge);
 171                 bytes -= uncharge;
 172                 sk_msg_iter_var_next(i);
 173         } while (i != msg->sg.end);
 174 }
 175 EXPORT_SYMBOL_GPL(sk_msg_return);
 176
 177 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
 178                             bool charge)
 179 {
 180         struct scatterlist *sge = sk_msg_elem(msg, i);
 181         u32 len = sge->length;
 182
 183         /* When the skb owns the memory we free it from consume_skb path. */
 184         if (!msg->skb) {
 185                 if (charge)
 186                         sk_mem_uncharge(sk, len);
 187                 put_page(sg_page(sge));
 188         }
 189         memset(sge, 0, sizeof(*sge));
 190         return len;
 191 }
 192
 193 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
 194                          bool charge)
 195 {
 196         struct scatterlist *sge = sk_msg_elem(msg, i);
 197         int freed = 0;
 198
 199         while (msg->sg.size) {
 200                 msg->sg.size -= sge->length;
 201                 freed += sk_msg_free_elem(sk, msg, i, charge);
 202                 sk_msg_iter_var_next(i);
 203                 sk_msg_check_to_free(msg, i, msg->sg.size);
 204                 sge = sk_msg_elem(msg, i);
 205         }
 206         consume_skb(msg->skb);
 207         sk_msg_init(msg);
 208         return freed;
 209 }
 210
 211 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
 212 {
 213         return __sk_msg_free(sk, msg, msg->sg.start, false);
 214 }
 215 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
 216
 217 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
 218 {
 219         return __sk_msg_free(sk, msg, msg->sg.start, true);
 220 }
 221 EXPORT_SYMBOL_GPL(sk_msg_free);
 222
 223 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
 224                                   u32 bytes, bool charge)
 225 {
 226         struct scatterlist *sge;
 227         u32 i = msg->sg.start;
 228
 229         while (bytes) {
 230                 sge = sk_msg_elem(msg, i);
 231                 if (!sge->length)
 232                         break;
 233                 if (bytes < sge->length) {
 234                         if (charge)
 235                                 sk_mem_uncharge(sk, bytes);
 236                         sge->length -= bytes;
 237                         sge->offset += bytes;
 238                         msg->sg.size -= bytes;
 239                         break;
 240                 }
 241
 242                 msg->sg.size -= sge->length;
 243                 bytes -= sge->length;
 244                 sk_msg_free_elem(sk, msg, i, charge);
 245                 sk_msg_iter_var_next(i);
 246                 sk_msg_check_to_free(msg, i, bytes);
 247         }
 248         msg->sg.start = i;
 249 }
 250
 251 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
 252 {
 253         __sk_msg_free_partial(sk, msg, bytes, true);
 254 }
 255 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
 256
 257 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
 258                                   u32 bytes)
 259 {
 260         __sk_msg_free_partial(sk, msg, bytes, false);
 261 }
 262
 263 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
 264 {
 265         int trim = msg->sg.size - len;
 266         u32 i = msg->sg.end;
 267
 268         if (trim <= 0) {
 269                 WARN_ON(trim < 0);
 270                 return;
 271         }
 272
 273         sk_msg_iter_var_prev(i);
 274         msg->sg.size = len;
 275         while (msg->sg.data[i].length &&
 276                trim >= msg->sg.data[i].length) {
 277                 trim -= msg->sg.data[i].length;
 278                 sk_msg_free_elem(sk, msg, i, true);
 279                 sk_msg_iter_var_prev(i);
 280                 if (!trim)
 281                         goto out;
 282         }
 283
 284         msg->sg.data[i].length -= trim;
 285         sk_mem_uncharge(sk, trim);
 286         /* Adjust copybreak if it falls into the trimmed part of last buf */
 287         if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
 288                 msg->sg.copybreak = msg->sg.data[i].length;
 289 out:
 290         sk_msg_iter_var_next(i);
 291         msg->sg.end = i;
 292
 293         /* If we trim data a full sg elem before curr pointer update
 294          * copybreak and current so that any future copy operations
 295          * start at new copy location.
 296          * However trimed data that has not yet been used in a copy op
 297          * does not require an update.
 298          */
 299         if (!msg->sg.size) {
 300                 msg->sg.curr = msg->sg.start;
 301                 msg->sg.copybreak = 0;
 302         } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
 303                    sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
 304                 sk_msg_iter_var_prev(i);
 305                 msg->sg.curr = i;
 306                 msg->sg.copybreak = msg->sg.data[i].length;
 307         }
 308 }
 309 EXPORT_SYMBOL_GPL(sk_msg_trim);
 310
 311 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 312                               struct sk_msg *msg, u32 bytes)
 313 {
 314         int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
 315         const int to_max_pages = MAX_MSG_FRAGS;
 316         struct page *pages[MAX_MSG_FRAGS];
 317         ssize_t orig, copied, use, offset;
 318
 319         orig = msg->sg.size;
 320         while (bytes > 0) {
 321                 i = 0;
 322                 maxpages = to_max_pages - num_elems;
 323                 if (maxpages == 0) {
 324                         ret = -EFAULT;
 325                         goto out;
 326                 }
 327
 328                 copied = iov_iter_get_pages2(from, pages, bytes, maxpages,
 329                                             &offset);
 330                 if (copied <= 0) {
 331                         ret = -EFAULT;
 332                         goto out;
 333                 }
 334
 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                         if (copy)
 438                                 copy = copy_page_to_iter(page, sge->offset, copy, iter);
 439                         if (!copy) {
 440                                 copied = copied ? copied : -EFAULT;
 441                                 goto out;
 442                         }
 443
 444                         copied += copy;
 445                         if (likely(!peek)) {
 446                                 sge->offset += copy;
 447                                 sge->length -= copy;
 448                                 if (!msg_rx->skb)
 449                                         sk_mem_uncharge(sk, copy);
 450                                 msg_rx->sg.size -= copy;
 451
 452                                 if (!sge->length) {
 453                                         sk_msg_iter_var_next(i);
 454                                         if (!msg_rx->skb)
 455                                                 put_page(page);
 456                                 }
 457                         } else {
 458                                 /* Lets not optimize peek case if copy_page_to_iter
 459                                  * didn't copy the entire length lets just break.
 460                                  */
 461                                 if (copy != sge->length)
 462                                         goto out;
 463                                 sk_msg_iter_var_next(i);
 464                         }
 465
 466                         if (copied == len)
 467                                 break;
 468                 } while ((i != msg_rx->sg.end) && !sg_is_last(sge));
 469
 470                 if (unlikely(peek)) {
 471                         msg_rx = sk_psock_next_msg(psock, msg_rx);
 472                         if (!msg_rx)
 473                                 break;
 474                         continue;
 475                 }
 476
 477                 msg_rx->sg.start = i;
 478                 if (!sge->length && (i == msg_rx->sg.end || sg_is_last(sge))) {
 479                         msg_rx = sk_psock_dequeue_msg(psock);
 480                         kfree_sk_msg(msg_rx);
 481                 }
 482                 msg_rx = sk_psock_peek_msg(psock);
 483         }
 484 out:
 485         return copied;
 486 }
 487 EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
 488
 489 bool sk_msg_is_readable(struct sock *sk)
 490 {
 491         struct sk_psock *psock;
 492         bool empty = true;
 493
 494         rcu_read_lock();
 495         psock = sk_psock(sk);
 496         if (likely(psock))
 497                 empty = list_empty(&psock->ingress_msg);
 498         rcu_read_unlock();
 499         return !empty;
 500 }
 501 EXPORT_SYMBOL_GPL(sk_msg_is_readable);
 502
 503 static struct sk_msg *alloc_sk_msg(gfp_t gfp)
 504 {
 505         struct sk_msg *msg;
 506
 507         msg = kzalloc(sizeof(*msg), gfp | __GFP_NOWARN);
 508         if (unlikely(!msg))
 509                 return NULL;
 510         sg_init_marker(msg->sg.data, NR_MSG_FRAG_IDS);
 511         return msg;
 512 }
 513
 514 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
 515                                                   struct sk_buff *skb)
 516 {
 517         if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
 518                 return NULL;
 519
 520         if (!sk_rmem_schedule(sk, skb, skb->truesize))
 521                 return NULL;
 522
 523         return alloc_sk_msg(GFP_KERNEL);
 524 }
 525
 526 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb,
 527                                         u32 off, u32 len,
 528                                         struct sk_psock *psock,
 529                                         struct sock *sk,
 530                                         struct sk_msg *msg)
 531 {
 532         int num_sge, copied;
 533
 534         num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
 535         if (num_sge < 0) {
 536                 /* skb linearize may fail with ENOMEM, but lets simply try again
 537                  * later if this happens. Under memory pressure we don't want to
 538                  * drop the skb. We need to linearize the skb so that the mapping
 539                  * in skb_to_sgvec can not error.
 540                  */
 541                 if (skb_linearize(skb))
 542                         return -EAGAIN;
 543
 544                 num_sge = skb_to_sgvec(skb, msg->sg.data, off, len);
 545                 if (unlikely(num_sge < 0))
 546                         return num_sge;
 547         }
 548
 549         copied = len;
 550         msg->sg.start = 0;
 551         msg->sg.size = copied;
 552         msg->sg.end = num_sge;
 553         msg->skb = skb;
 554
 555         sk_psock_queue_msg(psock, msg);
 556         sk_psock_data_ready(sk, psock);
 557         return copied;
 558 }
 559
 560 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
 561                                      u32 off, u32 len);
 562
 563 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb,
 564                                 u32 off, u32 len)
 565 {
 566         struct sock *sk = psock->sk;
 567         struct sk_msg *msg;
 568         int err;
 569
 570         /* If we are receiving on the same sock skb->sk is already assigned,
 571          * skip memory accounting and owner transition seeing it already set
 572          * correctly.
 573          */
 574         if (unlikely(skb->sk == sk))
 575                 return sk_psock_skb_ingress_self(psock, skb, off, len);
 576         msg = sk_psock_create_ingress_msg(sk, skb);
 577         if (!msg)
 578                 return -EAGAIN;
 579
 580         /* This will transition ownership of the data from the socket where
 581          * the BPF program was run initiating the redirect to the socket
 582          * we will eventually receive this data on. The data will be released
 583          * from skb_consume found in __tcp_bpf_recvmsg() after its been copied
 584          * into user buffers.
 585          */
 586         skb_set_owner_r(skb, sk);
 587         err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 588         if (err < 0)
 589                 kfree(msg);
 590         return err;
 591 }
 592
 593 /* Puts an skb on the ingress queue of the socket already assigned to the
 594  * skb. In this case we do not need to check memory limits or skb_set_owner_r
 595  * because the skb is already accounted for here.
 596  */
 597 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb,
 598                                      u32 off, u32 len)
 599 {
 600         struct sk_msg *msg = alloc_sk_msg(GFP_ATOMIC);
 601         struct sock *sk = psock->sk;
 602         int err;
 603
 604         if (unlikely(!msg))
 605                 return -EAGAIN;
 606         skb_set_owner_r(skb, sk);
 607         err = sk_psock_skb_ingress_enqueue(skb, off, len, psock, sk, msg);
 608         if (err < 0)
 609                 kfree(msg);
 610         return err;
 611 }
 612
 613 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
 614                                u32 off, u32 len, bool ingress)
 615 {
 616         int err = 0;
 617
 618         if (!ingress) {
 619                 if (!sock_writeable(psock->sk))
 620                         return -EAGAIN;
 621                 return skb_send_sock(psock->sk, skb, off, len);
 622         }
 623         skb_get(skb);
 624         err = sk_psock_skb_ingress(psock, skb, off, len);
 625         if (err < 0)
 626                 kfree_skb(skb);
 627         return err;
 628 }
 629
 630 static void sk_psock_skb_state(struct sk_psock *psock,
 631                                struct sk_psock_work_state *state,
 632                                int len, int off)
 633 {
 634         spin_lock_bh(&psock->ingress_lock);
 635         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
 636                 state->len = len;
 637                 state->off = off;
 638         }
 639         spin_unlock_bh(&psock->ingress_lock);
 640 }
 641
 642 static void sk_psock_backlog(struct work_struct *work)
 643 {
 644         struct delayed_work *dwork = to_delayed_work(work);
 645         struct sk_psock *psock = container_of(dwork, struct sk_psock, work);
 646         struct sk_psock_work_state *state = &psock->work_state;
 647         struct sk_buff *skb = NULL;
 648         u32 len = 0, off = 0;
 649         bool ingress;
 650         int ret;
 651
 652         mutex_lock(&psock->work_mutex);
 653         if (unlikely(state->len)) {
 654                 len = state->len;
 655                 off = state->off;
 656         }
 657
 658         while ((skb = skb_peek(&psock->ingress_skb))) {
 659                 len = skb->len;
 660                 off = 0;
 661                 if (skb_bpf_strparser(skb)) {
 662                         struct strp_msg *stm = strp_msg(skb);
 663
 664                         off = stm->offset;
 665                         len = stm->full_len;
 666                 }
 667                 ingress = skb_bpf_ingress(skb);
 668                 skb_bpf_redirect_clear(skb);
 669                 do {
 670                         ret = -EIO;
 671                         if (!sock_flag(psock->sk, SOCK_DEAD))
 672                                 ret = sk_psock_handle_skb(psock, skb, off,
 673                                                           len, ingress);
 674                         if (ret <= 0) {
 675                                 if (ret == -EAGAIN) {
 676                                         sk_psock_skb_state(psock, state, len, off);
 677
 678                                         /* Delay slightly to prioritize any
 679                                          * other work that might be here.
 680                                          */
 681                                         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 682                                                 schedule_delayed_work(&psock->work, 1);
 683                                         goto end;
 684                                 }
 685                                 /* Hard errors break pipe and stop xmit. */
 686                                 sk_psock_report_error(psock, ret ? -ret : EPIPE);
 687                                 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 688                                 goto end;
 689                         }
 690                         off += ret;
 691                         len -= ret;
 692                 } while (len);
 693
 694                 skb = skb_dequeue(&psock->ingress_skb);
 695                 kfree_skb(skb);
 696         }
 697 end:
 698         mutex_unlock(&psock->work_mutex);
 699 }
 700
 701 struct sk_psock *sk_psock_init(struct sock *sk, int node)
 702 {
 703         struct sk_psock *psock;
 704         struct proto *prot;
 705
 706         write_lock_bh(&sk->sk_callback_lock);
 707
 708         if (sk_is_inet(sk) && inet_csk_has_ulp(sk)) {
 709                 psock = ERR_PTR(-EINVAL);
 710                 goto out;
 711         }
 712
 713         if (sk->sk_user_data) {
 714                 psock = ERR_PTR(-EBUSY);
 715                 goto out;
 716         }
 717
 718         psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node);
 719         if (!psock) {
 720                 psock = ERR_PTR(-ENOMEM);
 721                 goto out;
 722         }
 723
 724         prot = READ_ONCE(sk->sk_prot);
 725         psock->sk = sk;
 726         psock->eval = __SK_NONE;
 727         psock->sk_proto = prot;
 728         psock->saved_unhash = prot->unhash;
 729         psock->saved_destroy = prot->destroy;
 730         psock->saved_close = prot->close;
 731         psock->saved_write_space = sk->sk_write_space;
 732
 733         INIT_LIST_HEAD(&psock->link);
 734         spin_lock_init(&psock->link_lock);
 735
 736         INIT_DELAYED_WORK(&psock->work, sk_psock_backlog);
 737         mutex_init(&psock->work_mutex);
 738         INIT_LIST_HEAD(&psock->ingress_msg);
 739         spin_lock_init(&psock->ingress_lock);
 740         skb_queue_head_init(&psock->ingress_skb);
 741
 742         sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
 743         refcount_set(&psock->refcnt, 1);
 744
 745         __rcu_assign_sk_user_data_with_flags(sk, psock,
 746                                              SK_USER_DATA_NOCOPY |
 747                                              SK_USER_DATA_PSOCK);
 748         sock_hold(sk);
 749
 750 out:
 751         write_unlock_bh(&sk->sk_callback_lock);
 752         return psock;
 753 }
 754 EXPORT_SYMBOL_GPL(sk_psock_init);
 755
 756 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
 757 {
 758         struct sk_psock_link *link;
 759
 760         spin_lock_bh(&psock->link_lock);
 761         link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
 762                                         list);
 763         if (link)
 764                 list_del(&link->list);
 765         spin_unlock_bh(&psock->link_lock);
 766         return link;
 767 }
 768
 769 static void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
 770 {
 771         struct sk_msg *msg, *tmp;
 772
 773         list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
 774                 list_del(&msg->list);
 775                 sk_msg_free(psock->sk, msg);
 776                 kfree(msg);
 777         }
 778 }
 779
 780 static void __sk_psock_zap_ingress(struct sk_psock *psock)
 781 {
 782         struct sk_buff *skb;
 783
 784         while ((skb = skb_dequeue(&psock->ingress_skb)) != NULL) {
 785                 skb_bpf_redirect_clear(skb);
 786                 sock_drop(psock->sk, skb);
 787         }
 788         __sk_psock_purge_ingress_msg(psock);
 789 }
 790
 791 static void sk_psock_link_destroy(struct sk_psock *psock)
 792 {
 793         struct sk_psock_link *link, *tmp;
 794
 795         list_for_each_entry_safe(link, tmp, &psock->link, list) {
 796                 list_del(&link->list);
 797                 sk_psock_free_link(link);
 798         }
 799 }
 800
 801 void sk_psock_stop(struct sk_psock *psock)
 802 {
 803         spin_lock_bh(&psock->ingress_lock);
 804         sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 805         sk_psock_cork_free(psock);
 806         spin_unlock_bh(&psock->ingress_lock);
 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_delayed_work_sync(&psock->work);
 820         __sk_psock_zap_ingress(psock);
 821         mutex_destroy(&psock->work_mutex);
 822
 823         psock_progs_drop(&psock->progs);
 824
 825         sk_psock_link_destroy(psock);
 826         sk_psock_cork_free(psock);
 827
 828         if (psock->sk_redir)
 829                 sock_put(psock->sk_redir);
 830         if (psock->sk_pair)
 831                 sock_put(psock->sk_pair);
 832         sock_put(psock->sk);
 833         kfree(psock);
 834 }
 835
 836 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 837 {
 838         write_lock_bh(&sk->sk_callback_lock);
 839         sk_psock_restore_proto(sk, psock);
 840         rcu_assign_sk_user_data(sk, NULL);
 841         if (psock->progs.stream_parser)
 842                 sk_psock_stop_strp(sk, psock);
 843         else if (psock->progs.stream_verdict || psock->progs.skb_verdict)
 844                 sk_psock_stop_verdict(sk, psock);
 845         write_unlock_bh(&sk->sk_callback_lock);
 846
 847         sk_psock_stop(psock);
 848
 849         INIT_RCU_WORK(&psock->rwork, sk_psock_destroy);
 850         queue_rcu_work(system_wq, &psock->rwork);
 851 }
 852 EXPORT_SYMBOL_GPL(sk_psock_drop);
 853
 854 static int sk_psock_map_verd(int verdict, bool redir)
 855 {
 856         switch (verdict) {
 857         case SK_PASS:
 858                 return redir ? __SK_REDIRECT : __SK_PASS;
 859         case SK_DROP:
 860         default:
 861                 break;
 862         }
 863
 864         return __SK_DROP;
 865 }
 866
 867 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 868                          struct sk_msg *msg)
 869 {
 870         struct bpf_prog *prog;
 871         int ret;
 872
 873         rcu_read_lock();
 874         prog = READ_ONCE(psock->progs.msg_parser);
 875         if (unlikely(!prog)) {
 876                 ret = __SK_PASS;
 877                 goto out;
 878         }
 879
 880         sk_msg_compute_data_pointers(msg);
 881         msg->sk = sk;
 882         ret = bpf_prog_run_pin_on_cpu(prog, msg);
 883         ret = sk_psock_map_verd(ret, msg->sk_redir);
 884         psock->apply_bytes = msg->apply_bytes;
 885         if (ret == __SK_REDIRECT) {
 886                 if (psock->sk_redir) {
 887                         sock_put(psock->sk_redir);
 888                         psock->sk_redir = NULL;
 889                 }
 890                 if (!msg->sk_redir) {
 891                         ret = __SK_DROP;
 892                         goto out;
 893                 }
 894                 psock->redir_ingress = sk_msg_to_ingress(msg);
 895                 psock->sk_redir = msg->sk_redir;
 896                 sock_hold(psock->sk_redir);
 897         }
 898 out:
 899         rcu_read_unlock();
 900         return ret;
 901 }
 902 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
 903
 904 static int sk_psock_skb_redirect(struct sk_psock *from, struct sk_buff *skb)
 905 {
 906         struct sk_psock *psock_other;
 907         struct sock *sk_other;
 908
 909         sk_other = skb_bpf_redirect_fetch(skb);
 910         /* This error is a buggy BPF program, it returned a redirect
 911          * return code, but then didn't set a redirect interface.
 912          */
 913         if (unlikely(!sk_other)) {
 914                 skb_bpf_redirect_clear(skb);
 915                 sock_drop(from->sk, skb);
 916                 return -EIO;
 917         }
 918         psock_other = sk_psock(sk_other);
 919         /* This error indicates the socket is being torn down or had another
 920          * error that caused the pipe to break. We can't send a packet on
 921          * a socket that is in this state so we drop the skb.
 922          */
 923         if (!psock_other || sock_flag(sk_other, SOCK_DEAD)) {
 924                 skb_bpf_redirect_clear(skb);
 925                 sock_drop(from->sk, skb);
 926                 return -EIO;
 927         }
 928         spin_lock_bh(&psock_other->ingress_lock);
 929         if (!sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) {
 930                 spin_unlock_bh(&psock_other->ingress_lock);
 931                 skb_bpf_redirect_clear(skb);
 932                 sock_drop(from->sk, skb);
 933                 return -EIO;
 934         }
 935
 936         skb_queue_tail(&psock_other->ingress_skb, skb);
 937         schedule_delayed_work(&psock_other->work, 0);
 938         spin_unlock_bh(&psock_other->ingress_lock);
 939         return 0;
 940 }
 941
 942 static void sk_psock_tls_verdict_apply(struct sk_buff *skb,
 943                                        struct sk_psock *from, int verdict)
 944 {
 945         switch (verdict) {
 946         case __SK_REDIRECT:
 947                 sk_psock_skb_redirect(from, skb);
 948                 break;
 949         case __SK_PASS:
 950         case __SK_DROP:
 951         default:
 952                 break;
 953         }
 954 }
 955
 956 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 957 {
 958         struct bpf_prog *prog;
 959         int ret = __SK_PASS;
 960
 961         rcu_read_lock();
 962         prog = READ_ONCE(psock->progs.stream_verdict);
 963         if (likely(prog)) {
 964                 skb->sk = psock->sk;
 965                 skb_dst_drop(skb);
 966                 skb_bpf_redirect_clear(skb);
 967                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
 968                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
 969                 skb->sk = NULL;
 970         }
 971         sk_psock_tls_verdict_apply(skb, psock, ret);
 972         rcu_read_unlock();
 973         return ret;
 974 }
 975 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read);
 976
 977 static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb,
 978                                   int verdict)
 979 {
 980         struct sock *sk_other;
 981         int err = 0;
 982         u32 len, off;
 983
 984         switch (verdict) {
 985         case __SK_PASS:
 986                 err = -EIO;
 987                 sk_other = psock->sk;
 988                 if (sock_flag(sk_other, SOCK_DEAD) ||
 989                     !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
 990                         goto out_free;
 991
 992                 skb_bpf_set_ingress(skb);
 993
 994                 /* If the queue is empty then we can submit directly
 995                  * into the msg queue. If its not empty we have to
 996                  * queue work otherwise we may get OOO data. Otherwise,
 997                  * if sk_psock_skb_ingress errors will be handled by
 998                  * retrying later from workqueue.
 999                  */
1000                 if (skb_queue_empty(&psock->ingress_skb)) {
1001                         len = skb->len;
1002                         off = 0;
1003                         if (skb_bpf_strparser(skb)) {
1004                                 struct strp_msg *stm = strp_msg(skb);
1005
1006                                 off = stm->offset;
1007                                 len = stm->full_len;
1008                         }
1009                         err = sk_psock_skb_ingress_self(psock, skb, off, len);
1010                 }
1011                 if (err < 0) {
1012                         spin_lock_bh(&psock->ingress_lock);
1013                         if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
1014                                 skb_queue_tail(&psock->ingress_skb, skb);
1015                                 schedule_delayed_work(&psock->work, 0);
1016                                 err = 0;
1017                         }
1018                         spin_unlock_bh(&psock->ingress_lock);
1019                         if (err < 0)
1020                                 goto out_free;
1021                 }
1022                 break;
1023         case __SK_REDIRECT:
1024                 tcp_eat_skb(psock->sk, skb);
1025                 err = sk_psock_skb_redirect(psock, skb);
1026                 break;
1027         case __SK_DROP:
1028         default:
1029 out_free:
1030                 skb_bpf_redirect_clear(skb);
1031                 tcp_eat_skb(psock->sk, skb);
1032                 sock_drop(psock->sk, skb);
1033         }
1034
1035         return err;
1036 }
1037
1038 static void sk_psock_write_space(struct sock *sk)
1039 {
1040         struct sk_psock *psock;
1041         void (*write_space)(struct sock *sk) = NULL;
1042
1043         rcu_read_lock();
1044         psock = sk_psock(sk);
1045         if (likely(psock)) {
1046                 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))
1047                         schedule_delayed_work(&psock->work, 0);
1048                 write_space = psock->saved_write_space;
1049         }
1050         rcu_read_unlock();
1051         if (write_space)
1052                 write_space(sk);
1053 }
1054
1055 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
1056 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
1057 {
1058         struct sk_psock *psock;
1059         struct bpf_prog *prog;
1060         int ret = __SK_DROP;
1061         struct sock *sk;
1062
1063         rcu_read_lock();
1064         sk = strp->sk;
1065         psock = sk_psock(sk);
1066         if (unlikely(!psock)) {
1067                 sock_drop(sk, skb);
1068                 goto out;
1069         }
1070         prog = READ_ONCE(psock->progs.stream_verdict);
1071         if (likely(prog)) {
1072                 skb->sk = sk;
1073                 skb_dst_drop(skb);
1074                 skb_bpf_redirect_clear(skb);
1075                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1076                 skb_bpf_set_strparser(skb);
1077                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1078                 skb->sk = NULL;
1079         }
1080         sk_psock_verdict_apply(psock, skb, ret);
1081 out:
1082         rcu_read_unlock();
1083 }
1084
1085 static int sk_psock_strp_read_done(struct strparser *strp, int err)
1086 {
1087         return err;
1088 }
1089
1090 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
1091 {
1092         struct sk_psock *psock = container_of(strp, struct sk_psock, strp);
1093         struct bpf_prog *prog;
1094         int ret = skb->len;
1095
1096         rcu_read_lock();
1097         prog = READ_ONCE(psock->progs.stream_parser);
1098         if (likely(prog)) {
1099                 skb->sk = psock->sk;
1100                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1101                 skb->sk = NULL;
1102         }
1103         rcu_read_unlock();
1104         return ret;
1105 }
1106
1107 /* Called with socket lock held. */
1108 static void sk_psock_strp_data_ready(struct sock *sk)
1109 {
1110         struct sk_psock *psock;
1111
1112         trace_sk_data_ready(sk);
1113
1114         rcu_read_lock();
1115         psock = sk_psock(sk);
1116         if (likely(psock)) {
1117                 if (tls_sw_has_ctx_rx(sk)) {
1118                         psock->saved_data_ready(sk);
1119                 } else {
1120                         write_lock_bh(&sk->sk_callback_lock);
1121                         strp_data_ready(&psock->strp);
1122                         write_unlock_bh(&sk->sk_callback_lock);
1123                 }
1124         }
1125         rcu_read_unlock();
1126 }
1127
1128 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
1129 {
1130         int ret;
1131
1132         static const struct strp_callbacks cb = {
1133                 .rcv_msg        = sk_psock_strp_read,
1134                 .read_sock_done = sk_psock_strp_read_done,
1135                 .parse_msg      = sk_psock_strp_parse,
1136         };
1137
1138         ret = strp_init(&psock->strp, sk, &cb);
1139         if (!ret)
1140                 sk_psock_set_state(psock, SK_PSOCK_RX_STRP_ENABLED);
1141
1142         return ret;
1143 }
1144
1145 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
1146 {
1147         if (psock->saved_data_ready)
1148                 return;
1149
1150         psock->saved_data_ready = sk->sk_data_ready;
1151         sk->sk_data_ready = sk_psock_strp_data_ready;
1152         sk->sk_write_space = sk_psock_write_space;
1153 }
1154
1155 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
1156 {
1157         psock_set_prog(&psock->progs.stream_parser, NULL);
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         strp_stop(&psock->strp);
1165 }
1166
1167 static void sk_psock_done_strp(struct sk_psock *psock)
1168 {
1169         /* Parser has been stopped */
1170         if (sk_psock_test_state(psock, SK_PSOCK_RX_STRP_ENABLED))
1171                 strp_done(&psock->strp);
1172 }
1173 #else
1174 static void sk_psock_done_strp(struct sk_psock *psock)
1175 {
1176 }
1177 #endif /* CONFIG_BPF_STREAM_PARSER */
1178
1179 static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb)
1180 {
1181         struct sk_psock *psock;
1182         struct bpf_prog *prog;
1183         int ret = __SK_DROP;
1184         int len = skb->len;
1185
1186         rcu_read_lock();
1187         psock = sk_psock(sk);
1188         if (unlikely(!psock)) {
1189                 len = 0;
1190                 tcp_eat_skb(sk, skb);
1191                 sock_drop(sk, skb);
1192                 goto out;
1193         }
1194         prog = READ_ONCE(psock->progs.stream_verdict);
1195         if (!prog)
1196                 prog = READ_ONCE(psock->progs.skb_verdict);
1197         if (likely(prog)) {
1198                 skb_dst_drop(skb);
1199                 skb_bpf_redirect_clear(skb);
1200                 ret = bpf_prog_run_pin_on_cpu(prog, skb);
1201                 ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb));
1202         }
1203         ret = sk_psock_verdict_apply(psock, skb, ret);
1204         if (ret < 0)
1205                 len = ret;
1206 out:
1207         rcu_read_unlock();
1208         return len;
1209 }
1210
1211 static void sk_psock_verdict_data_ready(struct sock *sk)
1212 {
1213         struct socket *sock = sk->sk_socket;
1214         const struct proto_ops *ops;
1215         int copied;
1216
1217         trace_sk_data_ready(sk);
1218
1219         if (unlikely(!sock))
1220                 return;
1221         ops = READ_ONCE(sock->ops);
1222         if (!ops || !ops->read_skb)
1223                 return;
1224         copied = ops->read_skb(sk, sk_psock_verdict_recv);
1225         if (copied >= 0) {
1226                 struct sk_psock *psock;
1227
1228                 rcu_read_lock();
1229                 psock = sk_psock(sk);
1230                 if (psock)
1231                         sk_psock_data_ready(sk, psock);
1232                 rcu_read_unlock();
1233         }
1234 }
1235
1236 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
1237 {
1238         if (psock->saved_data_ready)
1239                 return;
1240
1241         psock->saved_data_ready = sk->sk_data_ready;
1242         sk->sk_data_ready = sk_psock_verdict_data_ready;
1243         sk->sk_write_space = sk_psock_write_space;
1244 }
1245
1246 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
1247 {
1248         psock_set_prog(&psock->progs.stream_verdict, NULL);
1249         psock_set_prog(&psock->progs.skb_verdict, NULL);
1250
1251         if (!psock->saved_data_ready)
1252                 return;
1253
1254         sk->sk_data_ready = psock->saved_data_ready;
1255         psock->saved_data_ready = NULL;
1256 }