1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ 3 4 #include <linux/skmsg.h> 5 #include <linux/skbuff.h> 6 #include <linux/scatterlist.h> 7 8 #include <net/sock.h> 9 #include <net/tcp.h> 10 #include <net/tls.h> 11 12 static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce) 13 { 14 if (msg->sg.end > msg->sg.start && 15 elem_first_coalesce < msg->sg.end) 16 return true; 17 18 if (msg->sg.end < msg->sg.start && 19 (elem_first_coalesce > msg->sg.start || 20 elem_first_coalesce < msg->sg.end)) 21 return true; 22 23 return false; 24 } 25 26 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len, 27 int elem_first_coalesce) 28 { 29 struct page_frag *pfrag = sk_page_frag(sk); 30 int ret = 0; 31 32 len -= msg->sg.size; 33 while (len > 0) { 34 struct scatterlist *sge; 35 u32 orig_offset; 36 int use, i; 37 38 if (!sk_page_frag_refill(sk, pfrag)) 39 return -ENOMEM; 40 41 orig_offset = pfrag->offset; 42 use = min_t(int, len, pfrag->size - orig_offset); 43 if (!sk_wmem_schedule(sk, use)) 44 return -ENOMEM; 45 46 i = msg->sg.end; 47 sk_msg_iter_var_prev(i); 48 sge = &msg->sg.data[i]; 49 50 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) && 51 sg_page(sge) == pfrag->page && 52 sge->offset + sge->length == orig_offset) { 53 sge->length += use; 54 } else { 55 if (sk_msg_full(msg)) { 56 ret = -ENOSPC; 57 break; 58 } 59 60 sge = &msg->sg.data[msg->sg.end]; 61 sg_unmark_end(sge); 62 sg_set_page(sge, pfrag->page, use, orig_offset); 63 get_page(pfrag->page); 64 sk_msg_iter_next(msg, end); 65 } 66 67 sk_mem_charge(sk, use); 68 msg->sg.size += use; 69 pfrag->offset += use; 70 len -= use; 71 } 72 73 return ret; 74 } 75 EXPORT_SYMBOL_GPL(sk_msg_alloc); 76 77 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src, 78 u32 off, u32 len) 79 { 80 int i = src->sg.start; 81 struct scatterlist *sge = sk_msg_elem(src, i); 82 struct scatterlist *sgd = NULL; 83 u32 sge_len, sge_off; 84 85 while (off) { 86 if (sge->length > off) 87 break; 88 off -= sge->length; 89 sk_msg_iter_var_next(i); 90 if (i == src->sg.end && off) 91 return -ENOSPC; 92 sge = sk_msg_elem(src, i); 93 } 94 95 while (len) { 96 sge_len = sge->length - off; 97 if (sge_len > len) 98 sge_len = len; 99 100 if (dst->sg.end) 101 sgd = sk_msg_elem(dst, dst->sg.end - 1); 102 103 if (sgd && 104 (sg_page(sge) == sg_page(sgd)) && 105 (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) { 106 sgd->length += sge_len; 107 dst->sg.size += sge_len; 108 } else if (!sk_msg_full(dst)) { 109 sge_off = sge->offset + off; 110 sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off); 111 } else { 112 return -ENOSPC; 113 } 114 115 off = 0; 116 len -= sge_len; 117 sk_mem_charge(sk, sge_len); 118 sk_msg_iter_var_next(i); 119 if (i == src->sg.end && len) 120 return -ENOSPC; 121 sge = sk_msg_elem(src, i); 122 } 123 124 return 0; 125 } 126 EXPORT_SYMBOL_GPL(sk_msg_clone); 127 128 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes) 129 { 130 int i = msg->sg.start; 131 132 do { 133 struct scatterlist *sge = sk_msg_elem(msg, i); 134 135 if (bytes < sge->length) { 136 sge->length -= bytes; 137 sge->offset += bytes; 138 sk_mem_uncharge(sk, bytes); 139 break; 140 } 141 142 sk_mem_uncharge(sk, sge->length); 143 bytes -= sge->length; 144 sge->length = 0; 145 sge->offset = 0; 146 sk_msg_iter_var_next(i); 147 } while (bytes && i != msg->sg.end); 148 msg->sg.start = i; 149 } 150 EXPORT_SYMBOL_GPL(sk_msg_return_zero); 151 152 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes) 153 { 154 int i = msg->sg.start; 155 156 do { 157 struct scatterlist *sge = &msg->sg.data[i]; 158 int uncharge = (bytes < sge->length) ? bytes : sge->length; 159 160 sk_mem_uncharge(sk, uncharge); 161 bytes -= uncharge; 162 sk_msg_iter_var_next(i); 163 } while (i != msg->sg.end); 164 } 165 EXPORT_SYMBOL_GPL(sk_msg_return); 166 167 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i, 168 bool charge) 169 { 170 struct scatterlist *sge = sk_msg_elem(msg, i); 171 u32 len = sge->length; 172 173 /* When the skb owns the memory we free it from consume_skb path. */ 174 if (!msg->skb) { 175 if (charge) 176 sk_mem_uncharge(sk, len); 177 put_page(sg_page(sge)); 178 } 179 memset(sge, 0, sizeof(*sge)); 180 return len; 181 } 182 183 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i, 184 bool charge) 185 { 186 struct scatterlist *sge = sk_msg_elem(msg, i); 187 int freed = 0; 188 189 while (msg->sg.size) { 190 msg->sg.size -= sge->length; 191 freed += sk_msg_free_elem(sk, msg, i, charge); 192 sk_msg_iter_var_next(i); 193 sk_msg_check_to_free(msg, i, msg->sg.size); 194 sge = sk_msg_elem(msg, i); 195 } 196 consume_skb(msg->skb); 197 sk_msg_init(msg); 198 return freed; 199 } 200 201 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg) 202 { 203 return __sk_msg_free(sk, msg, msg->sg.start, false); 204 } 205 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge); 206 207 int sk_msg_free(struct sock *sk, struct sk_msg *msg) 208 { 209 return __sk_msg_free(sk, msg, msg->sg.start, true); 210 } 211 EXPORT_SYMBOL_GPL(sk_msg_free); 212 213 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, 214 u32 bytes, bool charge) 215 { 216 struct scatterlist *sge; 217 u32 i = msg->sg.start; 218 219 while (bytes) { 220 sge = sk_msg_elem(msg, i); 221 if (!sge->length) 222 break; 223 if (bytes < sge->length) { 224 if (charge) 225 sk_mem_uncharge(sk, bytes); 226 sge->length -= bytes; 227 sge->offset += bytes; 228 msg->sg.size -= bytes; 229 break; 230 } 231 232 msg->sg.size -= sge->length; 233 bytes -= sge->length; 234 sk_msg_free_elem(sk, msg, i, charge); 235 sk_msg_iter_var_next(i); 236 sk_msg_check_to_free(msg, i, bytes); 237 } 238 msg->sg.start = i; 239 } 240 241 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes) 242 { 243 __sk_msg_free_partial(sk, msg, bytes, true); 244 } 245 EXPORT_SYMBOL_GPL(sk_msg_free_partial); 246 247 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg, 248 u32 bytes) 249 { 250 __sk_msg_free_partial(sk, msg, bytes, false); 251 } 252 253 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len) 254 { 255 int trim = msg->sg.size - len; 256 u32 i = msg->sg.end; 257 258 if (trim <= 0) { 259 WARN_ON(trim < 0); 260 return; 261 } 262 263 sk_msg_iter_var_prev(i); 264 msg->sg.size = len; 265 while (msg->sg.data[i].length && 266 trim >= msg->sg.data[i].length) { 267 trim -= msg->sg.data[i].length; 268 sk_msg_free_elem(sk, msg, i, true); 269 sk_msg_iter_var_prev(i); 270 if (!trim) 271 goto out; 272 } 273 274 msg->sg.data[i].length -= trim; 275 sk_mem_uncharge(sk, trim); 276 /* Adjust copybreak if it falls into the trimmed part of last buf */ 277 if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length) 278 msg->sg.copybreak = msg->sg.data[i].length; 279 out: 280 sk_msg_iter_var_next(i); 281 msg->sg.end = i; 282 283 /* If we trim data a full sg elem before curr pointer update 284 * copybreak and current so that any future copy operations 285 * start at new copy location. 286 * However trimed data that has not yet been used in a copy op 287 * does not require an update. 288 */ 289 if (!msg->sg.size) { 290 msg->sg.curr = msg->sg.start; 291 msg->sg.copybreak = 0; 292 } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >= 293 sk_msg_iter_dist(msg->sg.start, msg->sg.end)) { 294 sk_msg_iter_var_prev(i); 295 msg->sg.curr = i; 296 msg->sg.copybreak = msg->sg.data[i].length; 297 } 298 } 299 EXPORT_SYMBOL_GPL(sk_msg_trim); 300 301 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, 302 struct sk_msg *msg, u32 bytes) 303 { 304 int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg); 305 const int to_max_pages = MAX_MSG_FRAGS; 306 struct page *pages[MAX_MSG_FRAGS]; 307 ssize_t orig, copied, use, offset; 308 309 orig = msg->sg.size; 310 while (bytes > 0) { 311 i = 0; 312 maxpages = to_max_pages - num_elems; 313 if (maxpages == 0) { 314 ret = -EFAULT; 315 goto out; 316 } 317 318 copied = iov_iter_get_pages(from, pages, bytes, maxpages, 319 &offset); 320 if (copied <= 0) { 321 ret = -EFAULT; 322 goto out; 323 } 324 325 iov_iter_advance(from, copied); 326 bytes -= copied; 327 msg->sg.size += copied; 328 329 while (copied) { 330 use = min_t(int, copied, PAGE_SIZE - offset); 331 sg_set_page(&msg->sg.data[msg->sg.end], 332 pages[i], use, offset); 333 sg_unmark_end(&msg->sg.data[msg->sg.end]); 334 sk_mem_charge(sk, use); 335 336 offset = 0; 337 copied -= use; 338 sk_msg_iter_next(msg, end); 339 num_elems++; 340 i++; 341 } 342 /* When zerocopy is mixed with sk_msg_*copy* operations we 343 * may have a copybreak set in this case clear and prefer 344 * zerocopy remainder when possible. 345 */ 346 msg->sg.copybreak = 0; 347 msg->sg.curr = msg->sg.end; 348 } 349 out: 350 /* Revert iov_iter updates, msg will need to use 'trim' later if it 351 * also needs to be cleared. 352 */ 353 if (ret) 354 iov_iter_revert(from, msg->sg.size - orig); 355 return ret; 356 } 357 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter); 358 359 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, 360 struct sk_msg *msg, u32 bytes) 361 { 362 int ret = -ENOSPC, i = msg->sg.curr; 363 struct scatterlist *sge; 364 u32 copy, buf_size; 365 void *to; 366 367 do { 368 sge = sk_msg_elem(msg, i); 369 /* This is possible if a trim operation shrunk the buffer */ 370 if (msg->sg.copybreak >= sge->length) { 371 msg->sg.copybreak = 0; 372 sk_msg_iter_var_next(i); 373 if (i == msg->sg.end) 374 break; 375 sge = sk_msg_elem(msg, i); 376 } 377 378 buf_size = sge->length - msg->sg.copybreak; 379 copy = (buf_size > bytes) ? bytes : buf_size; 380 to = sg_virt(sge) + msg->sg.copybreak; 381 msg->sg.copybreak += copy; 382 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) 383 ret = copy_from_iter_nocache(to, copy, from); 384 else 385 ret = copy_from_iter(to, copy, from); 386 if (ret != copy) { 387 ret = -EFAULT; 388 goto out; 389 } 390 bytes -= copy; 391 if (!bytes) 392 break; 393 msg->sg.copybreak = 0; 394 sk_msg_iter_var_next(i); 395 } while (i != msg->sg.end); 396 out: 397 msg->sg.curr = i; 398 return ret; 399 } 400 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter); 401 402 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk, 403 struct sk_buff *skb) 404 { 405 struct sk_msg *msg; 406 407 if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) 408 return NULL; 409 410 if (!sk_rmem_schedule(sk, skb, skb->truesize)) 411 return NULL; 412 413 msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC); 414 if (unlikely(!msg)) 415 return NULL; 416 417 sk_msg_init(msg); 418 return msg; 419 } 420 421 static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, 422 struct sk_psock *psock, 423 struct sock *sk, 424 struct sk_msg *msg) 425 { 426 int num_sge, copied; 427 428 /* skb linearize may fail with ENOMEM, but lets simply try again 429 * later if this happens. Under memory pressure we don't want to 430 * drop the skb. We need to linearize the skb so that the mapping 431 * in skb_to_sgvec can not error. 432 */ 433 if (skb_linearize(skb)) 434 return -EAGAIN; 435 num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); 436 if (unlikely(num_sge < 0)) { 437 kfree(msg); 438 return num_sge; 439 } 440 441 copied = skb->len; 442 msg->sg.start = 0; 443 msg->sg.size = copied; 444 msg->sg.end = num_sge; 445 msg->skb = skb; 446 447 sk_psock_queue_msg(psock, msg); 448 sk_psock_data_ready(sk, psock); 449 return copied; 450 } 451 452 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb); 453 454 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb) 455 { 456 struct sock *sk = psock->sk; 457 struct sk_msg *msg; 458 459 /* If we are receiving on the same sock skb->sk is already assigned, 460 * skip memory accounting and owner transition seeing it already set 461 * correctly. 462 */ 463 if (unlikely(skb->sk == sk)) 464 return sk_psock_skb_ingress_self(psock, skb); 465 msg = sk_psock_create_ingress_msg(sk, skb); 466 if (!msg) 467 return -EAGAIN; 468 469 /* This will transition ownership of the data from the socket where 470 * the BPF program was run initiating the redirect to the socket 471 * we will eventually receive this data on. The data will be released 472 * from skb_consume found in __tcp_bpf_recvmsg() after its been copied 473 * into user buffers. 474 */ 475 skb_set_owner_r(skb, sk); 476 return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); 477 } 478 479 /* Puts an skb on the ingress queue of the socket already assigned to the 480 * skb. In this case we do not need to check memory limits or skb_set_owner_r 481 * because the skb is already accounted for here. 482 */ 483 static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb) 484 { 485 struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC); 486 struct sock *sk = psock->sk; 487 488 if (unlikely(!msg)) 489 return -EAGAIN; 490 sk_msg_init(msg); 491 return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); 492 } 493 494 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb, 495 u32 off, u32 len, bool ingress) 496 { 497 if (!ingress) { 498 if (!sock_writeable(psock->sk)) 499 return -EAGAIN; 500 return skb_send_sock_locked(psock->sk, skb, off, len); 501 } 502 return sk_psock_skb_ingress(psock, skb); 503 } 504 505 static void sk_psock_backlog(struct work_struct *work) 506 { 507 struct sk_psock *psock = container_of(work, struct sk_psock, work); 508 struct sk_psock_work_state *state = &psock->work_state; 509 struct sk_buff *skb; 510 bool ingress; 511 u32 len, off; 512 int ret; 513 514 /* Lock sock to avoid losing sk_socket during loop. */ 515 lock_sock(psock->sk); 516 if (state->skb) { 517 skb = state->skb; 518 len = state->len; 519 off = state->off; 520 state->skb = NULL; 521 goto start; 522 } 523 524 while ((skb = skb_dequeue(&psock->ingress_skb))) { 525 len = skb->len; 526 off = 0; 527 start: 528 ingress = tcp_skb_bpf_ingress(skb); 529 do { 530 ret = -EIO; 531 if (likely(psock->sk->sk_socket)) 532 ret = sk_psock_handle_skb(psock, skb, off, 533 len, ingress); 534 if (ret <= 0) { 535 if (ret == -EAGAIN) { 536 state->skb = skb; 537 state->len = len; 538 state->off = off; 539 goto end; 540 } 541 /* Hard errors break pipe and stop xmit. */ 542 sk_psock_report_error(psock, ret ? -ret : EPIPE); 543 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED); 544 kfree_skb(skb); 545 goto end; 546 } 547 off += ret; 548 len -= ret; 549 } while (len); 550 551 if (!ingress) 552 kfree_skb(skb); 553 } 554 end: 555 release_sock(psock->sk); 556 } 557 558 struct sk_psock *sk_psock_init(struct sock *sk, int node) 559 { 560 struct sk_psock *psock; 561 struct proto *prot; 562 563 write_lock_bh(&sk->sk_callback_lock); 564 565 if (inet_csk_has_ulp(sk)) { 566 psock = ERR_PTR(-EINVAL); 567 goto out; 568 } 569 570 if (sk->sk_user_data) { 571 psock = ERR_PTR(-EBUSY); 572 goto out; 573 } 574 575 psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node); 576 if (!psock) { 577 psock = ERR_PTR(-ENOMEM); 578 goto out; 579 } 580 581 prot = READ_ONCE(sk->sk_prot); 582 psock->sk = sk; 583 psock->eval = __SK_NONE; 584 psock->sk_proto = prot; 585 psock->saved_unhash = prot->unhash; 586 psock->saved_close = prot->close; 587 psock->saved_write_space = sk->sk_write_space; 588 589 INIT_LIST_HEAD(&psock->link); 590 spin_lock_init(&psock->link_lock); 591 592 INIT_WORK(&psock->work, sk_psock_backlog); 593 INIT_LIST_HEAD(&psock->ingress_msg); 594 skb_queue_head_init(&psock->ingress_skb); 595 596 sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED); 597 refcount_set(&psock->refcnt, 1); 598 599 rcu_assign_sk_user_data_nocopy(sk, psock); 600 sock_hold(sk); 601 602 out: 603 write_unlock_bh(&sk->sk_callback_lock); 604 return psock; 605 } 606 EXPORT_SYMBOL_GPL(sk_psock_init); 607 608 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock) 609 { 610 struct sk_psock_link *link; 611 612 spin_lock_bh(&psock->link_lock); 613 link = list_first_entry_or_null(&psock->link, struct sk_psock_link, 614 list); 615 if (link) 616 list_del(&link->list); 617 spin_unlock_bh(&psock->link_lock); 618 return link; 619 } 620 621 void __sk_psock_purge_ingress_msg(struct sk_psock *psock) 622 { 623 struct sk_msg *msg, *tmp; 624 625 list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) { 626 list_del(&msg->list); 627 sk_msg_free(psock->sk, msg); 628 kfree(msg); 629 } 630 } 631 632 static void sk_psock_zap_ingress(struct sk_psock *psock) 633 { 634 __skb_queue_purge(&psock->ingress_skb); 635 __sk_psock_purge_ingress_msg(psock); 636 } 637 638 static void sk_psock_link_destroy(struct sk_psock *psock) 639 { 640 struct sk_psock_link *link, *tmp; 641 642 list_for_each_entry_safe(link, tmp, &psock->link, list) { 643 list_del(&link->list); 644 sk_psock_free_link(link); 645 } 646 } 647 648 static void sk_psock_destroy_deferred(struct work_struct *gc) 649 { 650 struct sk_psock *psock = container_of(gc, struct sk_psock, gc); 651 652 /* No sk_callback_lock since already detached. */ 653 654 /* Parser has been stopped */ 655 if (psock->progs.skb_parser) 656 strp_done(&psock->parser.strp); 657 658 cancel_work_sync(&psock->work); 659 660 psock_progs_drop(&psock->progs); 661 662 sk_psock_link_destroy(psock); 663 sk_psock_cork_free(psock); 664 sk_psock_zap_ingress(psock); 665 666 if (psock->sk_redir) 667 sock_put(psock->sk_redir); 668 sock_put(psock->sk); 669 kfree(psock); 670 } 671 672 void sk_psock_destroy(struct rcu_head *rcu) 673 { 674 struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu); 675 676 INIT_WORK(&psock->gc, sk_psock_destroy_deferred); 677 schedule_work(&psock->gc); 678 } 679 EXPORT_SYMBOL_GPL(sk_psock_destroy); 680 681 void sk_psock_drop(struct sock *sk, struct sk_psock *psock) 682 { 683 sk_psock_cork_free(psock); 684 sk_psock_zap_ingress(psock); 685 686 write_lock_bh(&sk->sk_callback_lock); 687 sk_psock_restore_proto(sk, psock); 688 rcu_assign_sk_user_data(sk, NULL); 689 if (psock->progs.skb_parser) 690 sk_psock_stop_strp(sk, psock); 691 else if (psock->progs.skb_verdict) 692 sk_psock_stop_verdict(sk, psock); 693 write_unlock_bh(&sk->sk_callback_lock); 694 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED); 695 696 call_rcu(&psock->rcu, sk_psock_destroy); 697 } 698 EXPORT_SYMBOL_GPL(sk_psock_drop); 699 700 static int sk_psock_map_verd(int verdict, bool redir) 701 { 702 switch (verdict) { 703 case SK_PASS: 704 return redir ? __SK_REDIRECT : __SK_PASS; 705 case SK_DROP: 706 default: 707 break; 708 } 709 710 return __SK_DROP; 711 } 712 713 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock, 714 struct sk_msg *msg) 715 { 716 struct bpf_prog *prog; 717 int ret; 718 719 rcu_read_lock(); 720 prog = READ_ONCE(psock->progs.msg_parser); 721 if (unlikely(!prog)) { 722 ret = __SK_PASS; 723 goto out; 724 } 725 726 sk_msg_compute_data_pointers(msg); 727 msg->sk = sk; 728 ret = bpf_prog_run_pin_on_cpu(prog, msg); 729 ret = sk_psock_map_verd(ret, msg->sk_redir); 730 psock->apply_bytes = msg->apply_bytes; 731 if (ret == __SK_REDIRECT) { 732 if (psock->sk_redir) 733 sock_put(psock->sk_redir); 734 psock->sk_redir = msg->sk_redir; 735 if (!psock->sk_redir) { 736 ret = __SK_DROP; 737 goto out; 738 } 739 sock_hold(psock->sk_redir); 740 } 741 out: 742 rcu_read_unlock(); 743 return ret; 744 } 745 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict); 746 747 static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog, 748 struct sk_buff *skb) 749 { 750 bpf_compute_data_end_sk_skb(skb); 751 return bpf_prog_run_pin_on_cpu(prog, skb); 752 } 753 754 static struct sk_psock *sk_psock_from_strp(struct strparser *strp) 755 { 756 struct sk_psock_parser *parser; 757 758 parser = container_of(strp, struct sk_psock_parser, strp); 759 return container_of(parser, struct sk_psock, parser); 760 } 761 762 static void sk_psock_skb_redirect(struct sk_buff *skb) 763 { 764 struct sk_psock *psock_other; 765 struct sock *sk_other; 766 767 sk_other = tcp_skb_bpf_redirect_fetch(skb); 768 /* This error is a buggy BPF program, it returned a redirect 769 * return code, but then didn't set a redirect interface. 770 */ 771 if (unlikely(!sk_other)) { 772 kfree_skb(skb); 773 return; 774 } 775 psock_other = sk_psock(sk_other); 776 /* This error indicates the socket is being torn down or had another 777 * error that caused the pipe to break. We can't send a packet on 778 * a socket that is in this state so we drop the skb. 779 */ 780 if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || 781 !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) { 782 kfree_skb(skb); 783 return; 784 } 785 786 skb_queue_tail(&psock_other->ingress_skb, skb); 787 schedule_work(&psock_other->work); 788 } 789 790 static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict) 791 { 792 switch (verdict) { 793 case __SK_REDIRECT: 794 skb_set_owner_r(skb, sk); 795 sk_psock_skb_redirect(skb); 796 break; 797 case __SK_PASS: 798 case __SK_DROP: 799 default: 800 break; 801 } 802 } 803 804 int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb) 805 { 806 struct bpf_prog *prog; 807 int ret = __SK_PASS; 808 809 rcu_read_lock(); 810 prog = READ_ONCE(psock->progs.skb_verdict); 811 if (likely(prog)) { 812 /* We skip full set_owner_r here because if we do a SK_PASS 813 * or SK_DROP we can skip skb memory accounting and use the 814 * TLS context. 815 */ 816 skb->sk = psock->sk; 817 tcp_skb_bpf_redirect_clear(skb); 818 ret = sk_psock_bpf_run(psock, prog, skb); 819 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); 820 skb->sk = NULL; 821 } 822 sk_psock_tls_verdict_apply(skb, psock->sk, ret); 823 rcu_read_unlock(); 824 return ret; 825 } 826 EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read); 827 828 static void sk_psock_verdict_apply(struct sk_psock *psock, 829 struct sk_buff *skb, int verdict) 830 { 831 struct tcp_skb_cb *tcp; 832 struct sock *sk_other; 833 int err = -EIO; 834 835 switch (verdict) { 836 case __SK_PASS: 837 sk_other = psock->sk; 838 if (sock_flag(sk_other, SOCK_DEAD) || 839 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { 840 goto out_free; 841 } 842 843 tcp = TCP_SKB_CB(skb); 844 tcp->bpf.flags |= BPF_F_INGRESS; 845 846 /* If the queue is empty then we can submit directly 847 * into the msg queue. If its not empty we have to 848 * queue work otherwise we may get OOO data. Otherwise, 849 * if sk_psock_skb_ingress errors will be handled by 850 * retrying later from workqueue. 851 */ 852 if (skb_queue_empty(&psock->ingress_skb)) { 853 err = sk_psock_skb_ingress_self(psock, skb); 854 } 855 if (err < 0) { 856 skb_queue_tail(&psock->ingress_skb, skb); 857 schedule_work(&psock->work); 858 } 859 break; 860 case __SK_REDIRECT: 861 sk_psock_skb_redirect(skb); 862 break; 863 case __SK_DROP: 864 default: 865 out_free: 866 kfree_skb(skb); 867 } 868 } 869 870 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb) 871 { 872 struct sk_psock *psock; 873 struct bpf_prog *prog; 874 int ret = __SK_DROP; 875 struct sock *sk; 876 877 rcu_read_lock(); 878 sk = strp->sk; 879 psock = sk_psock(sk); 880 if (unlikely(!psock)) { 881 kfree_skb(skb); 882 goto out; 883 } 884 skb_set_owner_r(skb, sk); 885 prog = READ_ONCE(psock->progs.skb_verdict); 886 if (likely(prog)) { 887 tcp_skb_bpf_redirect_clear(skb); 888 ret = sk_psock_bpf_run(psock, prog, skb); 889 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); 890 } 891 sk_psock_verdict_apply(psock, skb, ret); 892 out: 893 rcu_read_unlock(); 894 } 895 896 static int sk_psock_strp_read_done(struct strparser *strp, int err) 897 { 898 return err; 899 } 900 901 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb) 902 { 903 struct sk_psock *psock = sk_psock_from_strp(strp); 904 struct bpf_prog *prog; 905 int ret = skb->len; 906 907 rcu_read_lock(); 908 prog = READ_ONCE(psock->progs.skb_parser); 909 if (likely(prog)) { 910 skb->sk = psock->sk; 911 ret = sk_psock_bpf_run(psock, prog, skb); 912 skb->sk = NULL; 913 } 914 rcu_read_unlock(); 915 return ret; 916 } 917 918 /* Called with socket lock held. */ 919 static void sk_psock_strp_data_ready(struct sock *sk) 920 { 921 struct sk_psock *psock; 922 923 rcu_read_lock(); 924 psock = sk_psock(sk); 925 if (likely(psock)) { 926 if (tls_sw_has_ctx_rx(sk)) { 927 psock->parser.saved_data_ready(sk); 928 } else { 929 write_lock_bh(&sk->sk_callback_lock); 930 strp_data_ready(&psock->parser.strp); 931 write_unlock_bh(&sk->sk_callback_lock); 932 } 933 } 934 rcu_read_unlock(); 935 } 936 937 static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb, 938 unsigned int offset, size_t orig_len) 939 { 940 struct sock *sk = (struct sock *)desc->arg.data; 941 struct sk_psock *psock; 942 struct bpf_prog *prog; 943 int ret = __SK_DROP; 944 int len = skb->len; 945 946 /* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */ 947 skb = skb_clone(skb, GFP_ATOMIC); 948 if (!skb) { 949 desc->error = -ENOMEM; 950 return 0; 951 } 952 953 rcu_read_lock(); 954 psock = sk_psock(sk); 955 if (unlikely(!psock)) { 956 len = 0; 957 kfree_skb(skb); 958 goto out; 959 } 960 skb_set_owner_r(skb, sk); 961 prog = READ_ONCE(psock->progs.skb_verdict); 962 if (likely(prog)) { 963 tcp_skb_bpf_redirect_clear(skb); 964 ret = sk_psock_bpf_run(psock, prog, skb); 965 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); 966 } 967 sk_psock_verdict_apply(psock, skb, ret); 968 out: 969 rcu_read_unlock(); 970 return len; 971 } 972 973 static void sk_psock_verdict_data_ready(struct sock *sk) 974 { 975 struct socket *sock = sk->sk_socket; 976 read_descriptor_t desc; 977 978 if (unlikely(!sock || !sock->ops || !sock->ops->read_sock)) 979 return; 980 981 desc.arg.data = sk; 982 desc.error = 0; 983 desc.count = 1; 984 985 sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv); 986 } 987 988 static void sk_psock_write_space(struct sock *sk) 989 { 990 struct sk_psock *psock; 991 void (*write_space)(struct sock *sk) = NULL; 992 993 rcu_read_lock(); 994 psock = sk_psock(sk); 995 if (likely(psock)) { 996 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) 997 schedule_work(&psock->work); 998 write_space = psock->saved_write_space; 999 } 1000 rcu_read_unlock(); 1001 if (write_space) 1002 write_space(sk); 1003 } 1004 1005 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock) 1006 { 1007 static const struct strp_callbacks cb = { 1008 .rcv_msg = sk_psock_strp_read, 1009 .read_sock_done = sk_psock_strp_read_done, 1010 .parse_msg = sk_psock_strp_parse, 1011 }; 1012 1013 psock->parser.enabled = false; 1014 return strp_init(&psock->parser.strp, sk, &cb); 1015 } 1016 1017 void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock) 1018 { 1019 struct sk_psock_parser *parser = &psock->parser; 1020 1021 if (parser->enabled) 1022 return; 1023 1024 parser->saved_data_ready = sk->sk_data_ready; 1025 sk->sk_data_ready = sk_psock_verdict_data_ready; 1026 sk->sk_write_space = sk_psock_write_space; 1027 parser->enabled = true; 1028 } 1029 1030 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock) 1031 { 1032 struct sk_psock_parser *parser = &psock->parser; 1033 1034 if (parser->enabled) 1035 return; 1036 1037 parser->saved_data_ready = sk->sk_data_ready; 1038 sk->sk_data_ready = sk_psock_strp_data_ready; 1039 sk->sk_write_space = sk_psock_write_space; 1040 parser->enabled = true; 1041 } 1042 1043 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock) 1044 { 1045 struct sk_psock_parser *parser = &psock->parser; 1046 1047 if (!parser->enabled) 1048 return; 1049 1050 sk->sk_data_ready = parser->saved_data_ready; 1051 parser->saved_data_ready = NULL; 1052 strp_stop(&parser->strp); 1053 parser->enabled = false; 1054 } 1055 1056 void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock) 1057 { 1058 struct sk_psock_parser *parser = &psock->parser; 1059 1060 if (!parser->enabled) 1061 return; 1062 1063 sk->sk_data_ready = parser->saved_data_ready; 1064 parser->saved_data_ready = NULL; 1065 parser->enabled = false; 1066 } 1067