1 // SPDX-License-Identifier: GPL-2.0 2 /* Multipath TCP 3 * 4 * Copyright (c) 2017 - 2019, Intel Corporation. 5 */ 6 7 #define pr_fmt(fmt) "MPTCP: " fmt 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/netdevice.h> 12 #include <linux/sched/signal.h> 13 #include <linux/atomic.h> 14 #include <net/sock.h> 15 #include <net/inet_common.h> 16 #include <net/inet_hashtables.h> 17 #include <net/protocol.h> 18 #include <net/tcp.h> 19 #include <net/tcp_states.h> 20 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 21 #include <net/transp_v6.h> 22 #endif 23 #include <net/mptcp.h> 24 #include "protocol.h" 25 #include "mib.h" 26 27 #define MPTCP_SAME_STATE TCP_MAX_STATES 28 29 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 30 struct mptcp6_sock { 31 struct mptcp_sock msk; 32 struct ipv6_pinfo np; 33 }; 34 #endif 35 36 struct mptcp_skb_cb { 37 u32 offset; 38 }; 39 40 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) 41 42 static struct percpu_counter mptcp_sockets_allocated; 43 44 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not 45 * completed yet or has failed, return the subflow socket. 46 * Otherwise return NULL. 47 */ 48 static struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) 49 { 50 if (!msk->subflow || READ_ONCE(msk->can_ack)) 51 return NULL; 52 53 return msk->subflow; 54 } 55 56 static bool mptcp_is_tcpsk(struct sock *sk) 57 { 58 struct socket *sock = sk->sk_socket; 59 60 if (unlikely(sk->sk_prot == &tcp_prot)) { 61 /* we are being invoked after mptcp_accept() has 62 * accepted a non-mp-capable flow: sk is a tcp_sk, 63 * not an mptcp one. 64 * 65 * Hand the socket over to tcp so all further socket ops 66 * bypass mptcp. 67 */ 68 sock->ops = &inet_stream_ops; 69 return true; 70 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 71 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { 72 sock->ops = &inet6_stream_ops; 73 return true; 74 #endif 75 } 76 77 return false; 78 } 79 80 static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk) 81 { 82 sock_owned_by_me((const struct sock *)msk); 83 84 if (likely(!__mptcp_check_fallback(msk))) 85 return NULL; 86 87 return msk->first; 88 } 89 90 static int __mptcp_socket_create(struct mptcp_sock *msk) 91 { 92 struct mptcp_subflow_context *subflow; 93 struct sock *sk = (struct sock *)msk; 94 struct socket *ssock; 95 int err; 96 97 err = mptcp_subflow_create_socket(sk, &ssock); 98 if (err) 99 return err; 100 101 msk->first = ssock->sk; 102 msk->subflow = ssock; 103 subflow = mptcp_subflow_ctx(ssock->sk); 104 list_add(&subflow->node, &msk->conn_list); 105 subflow->request_mptcp = 1; 106 107 /* accept() will wait on first subflow sk_wq, and we always wakes up 108 * via msk->sk_socket 109 */ 110 RCU_INIT_POINTER(msk->first->sk_wq, &sk->sk_socket->wq); 111 112 return 0; 113 } 114 115 static void __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 116 struct sk_buff *skb, 117 unsigned int offset, size_t copy_len) 118 { 119 struct sock *sk = (struct sock *)msk; 120 struct sk_buff *tail; 121 122 __skb_unlink(skb, &ssk->sk_receive_queue); 123 124 skb_ext_reset(skb); 125 skb_orphan(skb); 126 msk->ack_seq += copy_len; 127 128 tail = skb_peek_tail(&sk->sk_receive_queue); 129 if (offset == 0 && tail) { 130 bool fragstolen; 131 int delta; 132 133 if (skb_try_coalesce(tail, skb, &fragstolen, &delta)) { 134 kfree_skb_partial(skb, fragstolen); 135 atomic_add(delta, &sk->sk_rmem_alloc); 136 sk_mem_charge(sk, delta); 137 return; 138 } 139 } 140 141 skb_set_owner_r(skb, sk); 142 __skb_queue_tail(&sk->sk_receive_queue, skb); 143 MPTCP_SKB_CB(skb)->offset = offset; 144 } 145 146 static void mptcp_stop_timer(struct sock *sk) 147 { 148 struct inet_connection_sock *icsk = inet_csk(sk); 149 150 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 151 mptcp_sk(sk)->timer_ival = 0; 152 } 153 154 /* both sockets must be locked */ 155 static bool mptcp_subflow_dsn_valid(const struct mptcp_sock *msk, 156 struct sock *ssk) 157 { 158 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 159 u64 dsn = mptcp_subflow_get_mapped_dsn(subflow); 160 161 /* revalidate data sequence number. 162 * 163 * mptcp_subflow_data_available() is usually called 164 * without msk lock. Its unlikely (but possible) 165 * that msk->ack_seq has been advanced since the last 166 * call found in-sequence data. 167 */ 168 if (likely(dsn == msk->ack_seq)) 169 return true; 170 171 subflow->data_avail = 0; 172 return mptcp_subflow_data_available(ssk); 173 } 174 175 static void mptcp_check_data_fin_ack(struct sock *sk) 176 { 177 struct mptcp_sock *msk = mptcp_sk(sk); 178 179 if (__mptcp_check_fallback(msk)) 180 return; 181 182 /* Look for an acknowledged DATA_FIN */ 183 if (((1 << sk->sk_state) & 184 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && 185 msk->write_seq == atomic64_read(&msk->snd_una)) { 186 mptcp_stop_timer(sk); 187 188 WRITE_ONCE(msk->snd_data_fin_enable, 0); 189 190 switch (sk->sk_state) { 191 case TCP_FIN_WAIT1: 192 inet_sk_state_store(sk, TCP_FIN_WAIT2); 193 sk->sk_state_change(sk); 194 break; 195 case TCP_CLOSING: 196 fallthrough; 197 case TCP_LAST_ACK: 198 inet_sk_state_store(sk, TCP_CLOSE); 199 sk->sk_state_change(sk); 200 break; 201 } 202 203 if (sk->sk_shutdown == SHUTDOWN_MASK || 204 sk->sk_state == TCP_CLOSE) 205 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 206 else 207 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 208 } 209 } 210 211 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 212 { 213 struct mptcp_sock *msk = mptcp_sk(sk); 214 215 if (READ_ONCE(msk->rcv_data_fin) && 216 ((1 << sk->sk_state) & 217 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { 218 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); 219 220 if (msk->ack_seq == rcv_data_fin_seq) { 221 if (seq) 222 *seq = rcv_data_fin_seq; 223 224 return true; 225 } 226 } 227 228 return false; 229 } 230 231 static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk) 232 { 233 long tout = ssk && inet_csk(ssk)->icsk_pending ? 234 inet_csk(ssk)->icsk_timeout - jiffies : 0; 235 236 if (tout <= 0) 237 tout = mptcp_sk(sk)->timer_ival; 238 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; 239 } 240 241 static void mptcp_check_data_fin(struct sock *sk) 242 { 243 struct mptcp_sock *msk = mptcp_sk(sk); 244 u64 rcv_data_fin_seq; 245 246 if (__mptcp_check_fallback(msk) || !msk->first) 247 return; 248 249 /* Need to ack a DATA_FIN received from a peer while this side 250 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. 251 * msk->rcv_data_fin was set when parsing the incoming options 252 * at the subflow level and the msk lock was not held, so this 253 * is the first opportunity to act on the DATA_FIN and change 254 * the msk state. 255 * 256 * If we are caught up to the sequence number of the incoming 257 * DATA_FIN, send the DATA_ACK now and do state transition. If 258 * not caught up, do nothing and let the recv code send DATA_ACK 259 * when catching up. 260 */ 261 262 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { 263 struct mptcp_subflow_context *subflow; 264 265 msk->ack_seq++; 266 WRITE_ONCE(msk->rcv_data_fin, 0); 267 268 sk->sk_shutdown |= RCV_SHUTDOWN; 269 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 270 set_bit(MPTCP_DATA_READY, &msk->flags); 271 272 switch (sk->sk_state) { 273 case TCP_ESTABLISHED: 274 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 275 break; 276 case TCP_FIN_WAIT1: 277 inet_sk_state_store(sk, TCP_CLOSING); 278 break; 279 case TCP_FIN_WAIT2: 280 inet_sk_state_store(sk, TCP_CLOSE); 281 // @@ Close subflows now? 282 break; 283 default: 284 /* Other states not expected */ 285 WARN_ON_ONCE(1); 286 break; 287 } 288 289 mptcp_set_timeout(sk, NULL); 290 mptcp_for_each_subflow(msk, subflow) { 291 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 292 293 lock_sock(ssk); 294 tcp_send_ack(ssk); 295 release_sock(ssk); 296 } 297 298 sk->sk_state_change(sk); 299 300 if (sk->sk_shutdown == SHUTDOWN_MASK || 301 sk->sk_state == TCP_CLOSE) 302 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 303 else 304 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 305 } 306 } 307 308 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 309 struct sock *ssk, 310 unsigned int *bytes) 311 { 312 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 313 struct sock *sk = (struct sock *)msk; 314 unsigned int moved = 0; 315 bool more_data_avail; 316 struct tcp_sock *tp; 317 bool done = false; 318 319 if (!mptcp_subflow_dsn_valid(msk, ssk)) { 320 *bytes = 0; 321 return false; 322 } 323 324 tp = tcp_sk(ssk); 325 do { 326 u32 map_remaining, offset; 327 u32 seq = tp->copied_seq; 328 struct sk_buff *skb; 329 bool fin; 330 331 /* try to move as much data as available */ 332 map_remaining = subflow->map_data_len - 333 mptcp_subflow_get_map_offset(subflow); 334 335 skb = skb_peek(&ssk->sk_receive_queue); 336 if (!skb) 337 break; 338 339 if (__mptcp_check_fallback(msk)) { 340 /* if we are running under the workqueue, TCP could have 341 * collapsed skbs between dummy map creation and now 342 * be sure to adjust the size 343 */ 344 map_remaining = skb->len; 345 subflow->map_data_len = skb->len; 346 } 347 348 offset = seq - TCP_SKB_CB(skb)->seq; 349 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; 350 if (fin) { 351 done = true; 352 seq++; 353 } 354 355 if (offset < skb->len) { 356 size_t len = skb->len - offset; 357 358 if (tp->urg_data) 359 done = true; 360 361 __mptcp_move_skb(msk, ssk, skb, offset, len); 362 seq += len; 363 moved += len; 364 365 if (WARN_ON_ONCE(map_remaining < len)) 366 break; 367 } else { 368 WARN_ON_ONCE(!fin); 369 sk_eat_skb(ssk, skb); 370 done = true; 371 } 372 373 WRITE_ONCE(tp->copied_seq, seq); 374 more_data_avail = mptcp_subflow_data_available(ssk); 375 376 if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) { 377 done = true; 378 break; 379 } 380 } while (more_data_avail); 381 382 *bytes = moved; 383 384 /* If the moves have caught up with the DATA_FIN sequence number 385 * it's time to ack the DATA_FIN and change socket state, but 386 * this is not a good place to change state. Let the workqueue 387 * do it. 388 */ 389 if (mptcp_pending_data_fin(sk, NULL) && 390 schedule_work(&msk->work)) 391 sock_hold(sk); 392 393 return done; 394 } 395 396 /* In most cases we will be able to lock the mptcp socket. If its already 397 * owned, we need to defer to the work queue to avoid ABBA deadlock. 398 */ 399 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 400 { 401 struct sock *sk = (struct sock *)msk; 402 unsigned int moved = 0; 403 404 if (READ_ONCE(sk->sk_lock.owned)) 405 return false; 406 407 if (unlikely(!spin_trylock_bh(&sk->sk_lock.slock))) 408 return false; 409 410 /* must re-check after taking the lock */ 411 if (!READ_ONCE(sk->sk_lock.owned)) 412 __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 413 414 spin_unlock_bh(&sk->sk_lock.slock); 415 416 return moved > 0; 417 } 418 419 void mptcp_data_ready(struct sock *sk, struct sock *ssk) 420 { 421 struct mptcp_sock *msk = mptcp_sk(sk); 422 423 set_bit(MPTCP_DATA_READY, &msk->flags); 424 425 if (atomic_read(&sk->sk_rmem_alloc) < READ_ONCE(sk->sk_rcvbuf) && 426 move_skbs_to_msk(msk, ssk)) 427 goto wake; 428 429 /* don't schedule if mptcp sk is (still) over limit */ 430 if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf)) 431 goto wake; 432 433 /* mptcp socket is owned, release_cb should retry */ 434 if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, 435 &sk->sk_tsq_flags)) { 436 sock_hold(sk); 437 438 /* need to try again, its possible release_cb() has already 439 * been called after the test_and_set_bit() above. 440 */ 441 move_skbs_to_msk(msk, ssk); 442 } 443 wake: 444 sk->sk_data_ready(sk); 445 } 446 447 static void __mptcp_flush_join_list(struct mptcp_sock *msk) 448 { 449 if (likely(list_empty(&msk->join_list))) 450 return; 451 452 spin_lock_bh(&msk->join_list_lock); 453 list_splice_tail_init(&msk->join_list, &msk->conn_list); 454 spin_unlock_bh(&msk->join_list_lock); 455 } 456 457 static bool mptcp_timer_pending(struct sock *sk) 458 { 459 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); 460 } 461 462 static void mptcp_reset_timer(struct sock *sk) 463 { 464 struct inet_connection_sock *icsk = inet_csk(sk); 465 unsigned long tout; 466 467 /* should never be called with mptcp level timer cleared */ 468 tout = READ_ONCE(mptcp_sk(sk)->timer_ival); 469 if (WARN_ON_ONCE(!tout)) 470 tout = TCP_RTO_MIN; 471 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); 472 } 473 474 void mptcp_data_acked(struct sock *sk) 475 { 476 mptcp_reset_timer(sk); 477 478 if ((!sk_stream_is_writeable(sk) || 479 (inet_sk_state_load(sk) != TCP_ESTABLISHED)) && 480 schedule_work(&mptcp_sk(sk)->work)) 481 sock_hold(sk); 482 } 483 484 void mptcp_subflow_eof(struct sock *sk) 485 { 486 struct mptcp_sock *msk = mptcp_sk(sk); 487 488 if (!test_and_set_bit(MPTCP_WORK_EOF, &msk->flags) && 489 schedule_work(&msk->work)) 490 sock_hold(sk); 491 } 492 493 static void mptcp_check_for_eof(struct mptcp_sock *msk) 494 { 495 struct mptcp_subflow_context *subflow; 496 struct sock *sk = (struct sock *)msk; 497 int receivers = 0; 498 499 mptcp_for_each_subflow(msk, subflow) 500 receivers += !subflow->rx_eof; 501 502 if (!receivers && !(sk->sk_shutdown & RCV_SHUTDOWN)) { 503 /* hopefully temporary hack: propagate shutdown status 504 * to msk, when all subflows agree on it 505 */ 506 sk->sk_shutdown |= RCV_SHUTDOWN; 507 508 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 509 set_bit(MPTCP_DATA_READY, &msk->flags); 510 sk->sk_data_ready(sk); 511 } 512 } 513 514 static bool mptcp_ext_cache_refill(struct mptcp_sock *msk) 515 { 516 const struct sock *sk = (const struct sock *)msk; 517 518 if (!msk->cached_ext) 519 msk->cached_ext = __skb_ext_alloc(sk->sk_allocation); 520 521 return !!msk->cached_ext; 522 } 523 524 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) 525 { 526 struct mptcp_subflow_context *subflow; 527 struct sock *sk = (struct sock *)msk; 528 529 sock_owned_by_me(sk); 530 531 mptcp_for_each_subflow(msk, subflow) { 532 if (subflow->data_avail) 533 return mptcp_subflow_tcp_sock(subflow); 534 } 535 536 return NULL; 537 } 538 539 static bool mptcp_skb_can_collapse_to(u64 write_seq, 540 const struct sk_buff *skb, 541 const struct mptcp_ext *mpext) 542 { 543 if (!tcp_skb_can_collapse_to(skb)) 544 return false; 545 546 /* can collapse only if MPTCP level sequence is in order */ 547 return mpext && mpext->data_seq + mpext->data_len == write_seq; 548 } 549 550 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 551 const struct page_frag *pfrag, 552 const struct mptcp_data_frag *df) 553 { 554 return df && pfrag->page == df->page && 555 df->data_seq + df->data_len == msk->write_seq; 556 } 557 558 static void dfrag_uncharge(struct sock *sk, int len) 559 { 560 sk_mem_uncharge(sk, len); 561 sk_wmem_queued_add(sk, -len); 562 } 563 564 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 565 { 566 int len = dfrag->data_len + dfrag->overhead; 567 568 list_del(&dfrag->list); 569 dfrag_uncharge(sk, len); 570 put_page(dfrag->page); 571 } 572 573 static void mptcp_clean_una(struct sock *sk) 574 { 575 struct mptcp_sock *msk = mptcp_sk(sk); 576 struct mptcp_data_frag *dtmp, *dfrag; 577 bool cleaned = false; 578 u64 snd_una; 579 580 /* on fallback we just need to ignore snd_una, as this is really 581 * plain TCP 582 */ 583 if (__mptcp_check_fallback(msk)) 584 atomic64_set(&msk->snd_una, msk->write_seq); 585 snd_una = atomic64_read(&msk->snd_una); 586 587 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 588 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 589 break; 590 591 dfrag_clear(sk, dfrag); 592 cleaned = true; 593 } 594 595 dfrag = mptcp_rtx_head(sk); 596 if (dfrag && after64(snd_una, dfrag->data_seq)) { 597 u64 delta = snd_una - dfrag->data_seq; 598 599 if (WARN_ON_ONCE(delta > dfrag->data_len)) 600 goto out; 601 602 dfrag->data_seq += delta; 603 dfrag->offset += delta; 604 dfrag->data_len -= delta; 605 606 dfrag_uncharge(sk, delta); 607 cleaned = true; 608 } 609 610 out: 611 if (cleaned) { 612 sk_mem_reclaim_partial(sk); 613 614 /* Only wake up writers if a subflow is ready */ 615 if (test_bit(MPTCP_SEND_SPACE, &msk->flags)) 616 sk_stream_write_space(sk); 617 } 618 } 619 620 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 621 * data 622 */ 623 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 624 { 625 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 626 pfrag, sk->sk_allocation))) 627 return true; 628 629 sk->sk_prot->enter_memory_pressure(sk); 630 sk_stream_moderate_sndbuf(sk); 631 return false; 632 } 633 634 static struct mptcp_data_frag * 635 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 636 int orig_offset) 637 { 638 int offset = ALIGN(orig_offset, sizeof(long)); 639 struct mptcp_data_frag *dfrag; 640 641 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 642 dfrag->data_len = 0; 643 dfrag->data_seq = msk->write_seq; 644 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 645 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 646 dfrag->page = pfrag->page; 647 648 return dfrag; 649 } 650 651 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 652 struct msghdr *msg, struct mptcp_data_frag *dfrag, 653 long *timeo, int *pmss_now, 654 int *ps_goal) 655 { 656 int mss_now, avail_size, size_goal, offset, ret, frag_truesize = 0; 657 bool dfrag_collapsed, can_collapse = false; 658 struct mptcp_sock *msk = mptcp_sk(sk); 659 struct mptcp_ext *mpext = NULL; 660 bool retransmission = !!dfrag; 661 struct sk_buff *skb, *tail; 662 struct page_frag *pfrag; 663 struct page *page; 664 u64 *write_seq; 665 size_t psize; 666 667 /* use the mptcp page cache so that we can easily move the data 668 * from one substream to another, but do per subflow memory accounting 669 * Note: pfrag is used only !retransmission, but the compiler if 670 * fooled into a warning if we don't init here 671 */ 672 pfrag = sk_page_frag(sk); 673 if (!retransmission) { 674 write_seq = &msk->write_seq; 675 page = pfrag->page; 676 } else { 677 write_seq = &dfrag->data_seq; 678 page = dfrag->page; 679 } 680 681 /* compute copy limit */ 682 mss_now = tcp_send_mss(ssk, &size_goal, msg->msg_flags); 683 *pmss_now = mss_now; 684 *ps_goal = size_goal; 685 avail_size = size_goal; 686 skb = tcp_write_queue_tail(ssk); 687 if (skb) { 688 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 689 690 /* Limit the write to the size available in the 691 * current skb, if any, so that we create at most a new skb. 692 * Explicitly tells TCP internals to avoid collapsing on later 693 * queue management operation, to avoid breaking the ext <-> 694 * SSN association set here 695 */ 696 can_collapse = (size_goal - skb->len > 0) && 697 mptcp_skb_can_collapse_to(*write_seq, skb, mpext); 698 if (!can_collapse) 699 TCP_SKB_CB(skb)->eor = 1; 700 else 701 avail_size = size_goal - skb->len; 702 } 703 704 if (!retransmission) { 705 /* reuse tail pfrag, if possible, or carve a new one from the 706 * page allocator 707 */ 708 dfrag = mptcp_rtx_tail(sk); 709 offset = pfrag->offset; 710 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 711 if (!dfrag_collapsed) { 712 dfrag = mptcp_carve_data_frag(msk, pfrag, offset); 713 offset = dfrag->offset; 714 frag_truesize = dfrag->overhead; 715 } 716 psize = min_t(size_t, pfrag->size - offset, avail_size); 717 718 /* Copy to page */ 719 pr_debug("left=%zu", msg_data_left(msg)); 720 psize = copy_page_from_iter(pfrag->page, offset, 721 min_t(size_t, msg_data_left(msg), 722 psize), 723 &msg->msg_iter); 724 pr_debug("left=%zu", msg_data_left(msg)); 725 if (!psize) 726 return -EINVAL; 727 728 if (!sk_wmem_schedule(sk, psize + dfrag->overhead)) { 729 iov_iter_revert(&msg->msg_iter, psize); 730 return -ENOMEM; 731 } 732 } else { 733 offset = dfrag->offset; 734 psize = min_t(size_t, dfrag->data_len, avail_size); 735 } 736 737 /* tell the TCP stack to delay the push so that we can safely 738 * access the skb after the sendpages call 739 */ 740 ret = do_tcp_sendpages(ssk, page, offset, psize, 741 msg->msg_flags | MSG_SENDPAGE_NOTLAST | MSG_DONTWAIT); 742 if (ret <= 0) { 743 if (!retransmission) 744 iov_iter_revert(&msg->msg_iter, psize); 745 return ret; 746 } 747 748 frag_truesize += ret; 749 if (!retransmission) { 750 if (unlikely(ret < psize)) 751 iov_iter_revert(&msg->msg_iter, psize - ret); 752 753 /* send successful, keep track of sent data for mptcp-level 754 * retransmission 755 */ 756 dfrag->data_len += ret; 757 if (!dfrag_collapsed) { 758 get_page(dfrag->page); 759 list_add_tail(&dfrag->list, &msk->rtx_queue); 760 sk_wmem_queued_add(sk, frag_truesize); 761 } else { 762 sk_wmem_queued_add(sk, ret); 763 } 764 765 /* charge data on mptcp rtx queue to the master socket 766 * Note: we charge such data both to sk and ssk 767 */ 768 sk->sk_forward_alloc -= frag_truesize; 769 } 770 771 /* if the tail skb extension is still the cached one, collapsing 772 * really happened. Note: we can't check for 'same skb' as the sk_buff 773 * hdr on tail can be transmitted, freed and re-allocated by the 774 * do_tcp_sendpages() call 775 */ 776 tail = tcp_write_queue_tail(ssk); 777 if (mpext && tail && mpext == skb_ext_find(tail, SKB_EXT_MPTCP)) { 778 WARN_ON_ONCE(!can_collapse); 779 mpext->data_len += ret; 780 goto out; 781 } 782 783 skb = tcp_write_queue_tail(ssk); 784 mpext = __skb_ext_set(skb, SKB_EXT_MPTCP, msk->cached_ext); 785 msk->cached_ext = NULL; 786 787 memset(mpext, 0, sizeof(*mpext)); 788 mpext->data_seq = *write_seq; 789 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 790 mpext->data_len = ret; 791 mpext->use_map = 1; 792 mpext->dsn64 = 1; 793 794 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 795 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 796 mpext->dsn64); 797 798 out: 799 if (!retransmission) 800 pfrag->offset += frag_truesize; 801 WRITE_ONCE(*write_seq, *write_seq + ret); 802 mptcp_subflow_ctx(ssk)->rel_write_seq += ret; 803 804 return ret; 805 } 806 807 static void mptcp_nospace(struct mptcp_sock *msk, struct socket *sock) 808 { 809 clear_bit(MPTCP_SEND_SPACE, &msk->flags); 810 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 811 812 /* enables sk->write_space() callbacks */ 813 set_bit(SOCK_NOSPACE, &sock->flags); 814 } 815 816 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 817 { 818 struct mptcp_subflow_context *subflow; 819 struct sock *backup = NULL; 820 821 sock_owned_by_me((const struct sock *)msk); 822 823 if (!mptcp_ext_cache_refill(msk)) 824 return NULL; 825 826 mptcp_for_each_subflow(msk, subflow) { 827 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 828 829 if (!sk_stream_memory_free(ssk)) { 830 struct socket *sock = ssk->sk_socket; 831 832 if (sock) 833 mptcp_nospace(msk, sock); 834 835 return NULL; 836 } 837 838 if (subflow->backup) { 839 if (!backup) 840 backup = ssk; 841 842 continue; 843 } 844 845 return ssk; 846 } 847 848 return backup; 849 } 850 851 static void ssk_check_wmem(struct mptcp_sock *msk, struct sock *ssk) 852 { 853 struct socket *sock; 854 855 if (likely(sk_stream_is_writeable(ssk))) 856 return; 857 858 sock = READ_ONCE(ssk->sk_socket); 859 if (sock) 860 mptcp_nospace(msk, sock); 861 } 862 863 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 864 { 865 int mss_now = 0, size_goal = 0, ret = 0; 866 struct mptcp_sock *msk = mptcp_sk(sk); 867 struct page_frag *pfrag; 868 size_t copied = 0; 869 struct sock *ssk; 870 bool tx_ok; 871 long timeo; 872 873 if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL)) 874 return -EOPNOTSUPP; 875 876 lock_sock(sk); 877 878 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 879 880 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 881 ret = sk_stream_wait_connect(sk, &timeo); 882 if (ret) 883 goto out; 884 } 885 886 pfrag = sk_page_frag(sk); 887 restart: 888 mptcp_clean_una(sk); 889 890 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { 891 ret = -EPIPE; 892 goto out; 893 } 894 895 wait_for_sndbuf: 896 __mptcp_flush_join_list(msk); 897 ssk = mptcp_subflow_get_send(msk); 898 while (!sk_stream_memory_free(sk) || 899 !ssk || 900 !mptcp_page_frag_refill(ssk, pfrag)) { 901 if (ssk) { 902 /* make sure retransmit timer is 903 * running before we wait for memory. 904 * 905 * The retransmit timer might be needed 906 * to make the peer send an up-to-date 907 * MPTCP Ack. 908 */ 909 mptcp_set_timeout(sk, ssk); 910 if (!mptcp_timer_pending(sk)) 911 mptcp_reset_timer(sk); 912 } 913 914 ret = sk_stream_wait_memory(sk, &timeo); 915 if (ret) 916 goto out; 917 918 mptcp_clean_una(sk); 919 920 ssk = mptcp_subflow_get_send(msk); 921 if (list_empty(&msk->conn_list)) { 922 ret = -ENOTCONN; 923 goto out; 924 } 925 } 926 927 pr_debug("conn_list->subflow=%p", ssk); 928 929 lock_sock(ssk); 930 tx_ok = msg_data_left(msg); 931 while (tx_ok) { 932 ret = mptcp_sendmsg_frag(sk, ssk, msg, NULL, &timeo, &mss_now, 933 &size_goal); 934 if (ret < 0) { 935 if (ret == -EAGAIN && timeo > 0) { 936 mptcp_set_timeout(sk, ssk); 937 release_sock(ssk); 938 goto restart; 939 } 940 break; 941 } 942 943 copied += ret; 944 945 tx_ok = msg_data_left(msg); 946 if (!tx_ok) 947 break; 948 949 if (!sk_stream_memory_free(ssk) || 950 !mptcp_page_frag_refill(ssk, pfrag) || 951 !mptcp_ext_cache_refill(msk)) { 952 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 953 tcp_push(ssk, msg->msg_flags, mss_now, 954 tcp_sk(ssk)->nonagle, size_goal); 955 mptcp_set_timeout(sk, ssk); 956 release_sock(ssk); 957 goto restart; 958 } 959 960 /* memory is charged to mptcp level socket as well, i.e. 961 * if msg is very large, mptcp socket may run out of buffer 962 * space. mptcp_clean_una() will release data that has 963 * been acked at mptcp level in the mean time, so there is 964 * a good chance we can continue sending data right away. 965 * 966 * Normally, when the tcp subflow can accept more data, then 967 * so can the MPTCP socket. However, we need to cope with 968 * peers that might lag behind in their MPTCP-level 969 * acknowledgements, i.e. data might have been acked at 970 * tcp level only. So, we must also check the MPTCP socket 971 * limits before we send more data. 972 */ 973 if (unlikely(!sk_stream_memory_free(sk))) { 974 tcp_push(ssk, msg->msg_flags, mss_now, 975 tcp_sk(ssk)->nonagle, size_goal); 976 mptcp_clean_una(sk); 977 if (!sk_stream_memory_free(sk)) { 978 /* can't send more for now, need to wait for 979 * MPTCP-level ACKs from peer. 980 * 981 * Wakeup will happen via mptcp_clean_una(). 982 */ 983 mptcp_set_timeout(sk, ssk); 984 release_sock(ssk); 985 goto wait_for_sndbuf; 986 } 987 } 988 } 989 990 mptcp_set_timeout(sk, ssk); 991 if (copied) { 992 tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, 993 size_goal); 994 995 /* start the timer, if it's not pending */ 996 if (!mptcp_timer_pending(sk)) 997 mptcp_reset_timer(sk); 998 } 999 1000 ssk_check_wmem(msk, ssk); 1001 release_sock(ssk); 1002 out: 1003 release_sock(sk); 1004 return copied ? : ret; 1005 } 1006 1007 static void mptcp_wait_data(struct sock *sk, long *timeo) 1008 { 1009 DEFINE_WAIT_FUNC(wait, woken_wake_function); 1010 struct mptcp_sock *msk = mptcp_sk(sk); 1011 1012 add_wait_queue(sk_sleep(sk), &wait); 1013 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1014 1015 sk_wait_event(sk, timeo, 1016 test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait); 1017 1018 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1019 remove_wait_queue(sk_sleep(sk), &wait); 1020 } 1021 1022 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1023 struct msghdr *msg, 1024 size_t len) 1025 { 1026 struct sock *sk = (struct sock *)msk; 1027 struct sk_buff *skb; 1028 int copied = 0; 1029 1030 while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) { 1031 u32 offset = MPTCP_SKB_CB(skb)->offset; 1032 u32 data_len = skb->len - offset; 1033 u32 count = min_t(size_t, len - copied, data_len); 1034 int err; 1035 1036 err = skb_copy_datagram_msg(skb, offset, msg, count); 1037 if (unlikely(err < 0)) { 1038 if (!copied) 1039 return err; 1040 break; 1041 } 1042 1043 copied += count; 1044 1045 if (count < data_len) { 1046 MPTCP_SKB_CB(skb)->offset += count; 1047 break; 1048 } 1049 1050 __skb_unlink(skb, &sk->sk_receive_queue); 1051 __kfree_skb(skb); 1052 1053 if (copied >= len) 1054 break; 1055 } 1056 1057 return copied; 1058 } 1059 1060 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1061 * 1062 * Only difference: Use highest rtt estimate of the subflows in use. 1063 */ 1064 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1065 { 1066 struct mptcp_subflow_context *subflow; 1067 struct sock *sk = (struct sock *)msk; 1068 u32 time, advmss = 1; 1069 u64 rtt_us, mstamp; 1070 1071 sock_owned_by_me(sk); 1072 1073 if (copied <= 0) 1074 return; 1075 1076 msk->rcvq_space.copied += copied; 1077 1078 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1079 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1080 1081 rtt_us = msk->rcvq_space.rtt_us; 1082 if (rtt_us && time < (rtt_us >> 3)) 1083 return; 1084 1085 rtt_us = 0; 1086 mptcp_for_each_subflow(msk, subflow) { 1087 const struct tcp_sock *tp; 1088 u64 sf_rtt_us; 1089 u32 sf_advmss; 1090 1091 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1092 1093 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1094 sf_advmss = READ_ONCE(tp->advmss); 1095 1096 rtt_us = max(sf_rtt_us, rtt_us); 1097 advmss = max(sf_advmss, advmss); 1098 } 1099 1100 msk->rcvq_space.rtt_us = rtt_us; 1101 if (time < (rtt_us >> 3) || rtt_us == 0) 1102 return; 1103 1104 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 1105 goto new_measure; 1106 1107 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && 1108 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 1109 int rcvmem, rcvbuf; 1110 u64 rcvwin, grow; 1111 1112 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 1113 1114 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 1115 1116 do_div(grow, msk->rcvq_space.space); 1117 rcvwin += (grow << 1); 1118 1119 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER); 1120 while (tcp_win_from_space(sk, rcvmem) < advmss) 1121 rcvmem += 128; 1122 1123 do_div(rcvwin, advmss); 1124 rcvbuf = min_t(u64, rcvwin * rcvmem, 1125 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); 1126 1127 if (rcvbuf > sk->sk_rcvbuf) { 1128 u32 window_clamp; 1129 1130 window_clamp = tcp_win_from_space(sk, rcvbuf); 1131 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 1132 1133 /* Make subflows follow along. If we do not do this, we 1134 * get drops at subflow level if skbs can't be moved to 1135 * the mptcp rx queue fast enough (announced rcv_win can 1136 * exceed ssk->sk_rcvbuf). 1137 */ 1138 mptcp_for_each_subflow(msk, subflow) { 1139 struct sock *ssk; 1140 1141 ssk = mptcp_subflow_tcp_sock(subflow); 1142 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 1143 tcp_sk(ssk)->window_clamp = window_clamp; 1144 } 1145 } 1146 } 1147 1148 msk->rcvq_space.space = msk->rcvq_space.copied; 1149 new_measure: 1150 msk->rcvq_space.copied = 0; 1151 msk->rcvq_space.time = mstamp; 1152 } 1153 1154 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 1155 { 1156 unsigned int moved = 0; 1157 bool done; 1158 1159 do { 1160 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 1161 1162 if (!ssk) 1163 break; 1164 1165 lock_sock(ssk); 1166 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 1167 release_sock(ssk); 1168 } while (!done); 1169 1170 return moved > 0; 1171 } 1172 1173 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 1174 int nonblock, int flags, int *addr_len) 1175 { 1176 struct mptcp_sock *msk = mptcp_sk(sk); 1177 int copied = 0; 1178 int target; 1179 long timeo; 1180 1181 if (msg->msg_flags & ~(MSG_WAITALL | MSG_DONTWAIT)) 1182 return -EOPNOTSUPP; 1183 1184 lock_sock(sk); 1185 timeo = sock_rcvtimeo(sk, nonblock); 1186 1187 len = min_t(size_t, len, INT_MAX); 1188 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1189 __mptcp_flush_join_list(msk); 1190 1191 while (len > (size_t)copied) { 1192 int bytes_read; 1193 1194 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied); 1195 if (unlikely(bytes_read < 0)) { 1196 if (!copied) 1197 copied = bytes_read; 1198 goto out_err; 1199 } 1200 1201 copied += bytes_read; 1202 1203 if (skb_queue_empty(&sk->sk_receive_queue) && 1204 __mptcp_move_skbs(msk)) 1205 continue; 1206 1207 /* only the master socket status is relevant here. The exit 1208 * conditions mirror closely tcp_recvmsg() 1209 */ 1210 if (copied >= target) 1211 break; 1212 1213 if (copied) { 1214 if (sk->sk_err || 1215 sk->sk_state == TCP_CLOSE || 1216 (sk->sk_shutdown & RCV_SHUTDOWN) || 1217 !timeo || 1218 signal_pending(current)) 1219 break; 1220 } else { 1221 if (sk->sk_err) { 1222 copied = sock_error(sk); 1223 break; 1224 } 1225 1226 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 1227 mptcp_check_for_eof(msk); 1228 1229 if (sk->sk_shutdown & RCV_SHUTDOWN) 1230 break; 1231 1232 if (sk->sk_state == TCP_CLOSE) { 1233 copied = -ENOTCONN; 1234 break; 1235 } 1236 1237 if (!timeo) { 1238 copied = -EAGAIN; 1239 break; 1240 } 1241 1242 if (signal_pending(current)) { 1243 copied = sock_intr_errno(timeo); 1244 break; 1245 } 1246 } 1247 1248 pr_debug("block timeout %ld", timeo); 1249 mptcp_wait_data(sk, &timeo); 1250 } 1251 1252 if (skb_queue_empty(&sk->sk_receive_queue)) { 1253 /* entire backlog drained, clear DATA_READY. */ 1254 clear_bit(MPTCP_DATA_READY, &msk->flags); 1255 1256 /* .. race-breaker: ssk might have gotten new data 1257 * after last __mptcp_move_skbs() returned false. 1258 */ 1259 if (unlikely(__mptcp_move_skbs(msk))) 1260 set_bit(MPTCP_DATA_READY, &msk->flags); 1261 } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) { 1262 /* data to read but mptcp_wait_data() cleared DATA_READY */ 1263 set_bit(MPTCP_DATA_READY, &msk->flags); 1264 } 1265 out_err: 1266 mptcp_rcv_space_adjust(msk, copied); 1267 1268 release_sock(sk); 1269 return copied; 1270 } 1271 1272 static void mptcp_retransmit_handler(struct sock *sk) 1273 { 1274 struct mptcp_sock *msk = mptcp_sk(sk); 1275 1276 if (atomic64_read(&msk->snd_una) == READ_ONCE(msk->write_seq)) { 1277 mptcp_stop_timer(sk); 1278 } else { 1279 set_bit(MPTCP_WORK_RTX, &msk->flags); 1280 if (schedule_work(&msk->work)) 1281 sock_hold(sk); 1282 } 1283 } 1284 1285 static void mptcp_retransmit_timer(struct timer_list *t) 1286 { 1287 struct inet_connection_sock *icsk = from_timer(icsk, t, 1288 icsk_retransmit_timer); 1289 struct sock *sk = &icsk->icsk_inet.sk; 1290 1291 bh_lock_sock(sk); 1292 if (!sock_owned_by_user(sk)) { 1293 mptcp_retransmit_handler(sk); 1294 } else { 1295 /* delegate our work to tcp_release_cb() */ 1296 if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, 1297 &sk->sk_tsq_flags)) 1298 sock_hold(sk); 1299 } 1300 bh_unlock_sock(sk); 1301 sock_put(sk); 1302 } 1303 1304 /* Find an idle subflow. Return NULL if there is unacked data at tcp 1305 * level. 1306 * 1307 * A backup subflow is returned only if that is the only kind available. 1308 */ 1309 static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk) 1310 { 1311 struct mptcp_subflow_context *subflow; 1312 struct sock *backup = NULL; 1313 1314 sock_owned_by_me((const struct sock *)msk); 1315 1316 mptcp_for_each_subflow(msk, subflow) { 1317 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1318 1319 /* still data outstanding at TCP level? Don't retransmit. */ 1320 if (!tcp_write_queue_empty(ssk)) 1321 return NULL; 1322 1323 if (subflow->backup) { 1324 if (!backup) 1325 backup = ssk; 1326 continue; 1327 } 1328 1329 return ssk; 1330 } 1331 1332 return backup; 1333 } 1334 1335 /* subflow sockets can be either outgoing (connect) or incoming 1336 * (accept). 1337 * 1338 * Outgoing subflows use in-kernel sockets. 1339 * Incoming subflows do not have their own 'struct socket' allocated, 1340 * so we need to use tcp_close() after detaching them from the mptcp 1341 * parent socket. 1342 */ 1343 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 1344 struct mptcp_subflow_context *subflow, 1345 long timeout) 1346 { 1347 struct socket *sock = READ_ONCE(ssk->sk_socket); 1348 1349 list_del(&subflow->node); 1350 1351 if (sock && sock != sk->sk_socket) { 1352 /* outgoing subflow */ 1353 sock_release(sock); 1354 } else { 1355 /* incoming subflow */ 1356 tcp_close(ssk, timeout); 1357 } 1358 } 1359 1360 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 1361 { 1362 return 0; 1363 } 1364 1365 static void pm_work(struct mptcp_sock *msk) 1366 { 1367 struct mptcp_pm_data *pm = &msk->pm; 1368 1369 spin_lock_bh(&msk->pm.lock); 1370 1371 pr_debug("msk=%p status=%x", msk, pm->status); 1372 if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) { 1373 pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED); 1374 mptcp_pm_nl_add_addr_received(msk); 1375 } 1376 if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) { 1377 pm->status &= ~BIT(MPTCP_PM_ESTABLISHED); 1378 mptcp_pm_nl_fully_established(msk); 1379 } 1380 if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) { 1381 pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED); 1382 mptcp_pm_nl_subflow_established(msk); 1383 } 1384 1385 spin_unlock_bh(&msk->pm.lock); 1386 } 1387 1388 static void mptcp_worker(struct work_struct *work) 1389 { 1390 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 1391 struct sock *ssk, *sk = &msk->sk.icsk_inet.sk; 1392 int orig_len, orig_offset, mss_now = 0, size_goal = 0; 1393 struct mptcp_data_frag *dfrag; 1394 u64 orig_write_seq; 1395 size_t copied = 0; 1396 struct msghdr msg = { 1397 .msg_flags = MSG_DONTWAIT, 1398 }; 1399 long timeo = 0; 1400 1401 lock_sock(sk); 1402 mptcp_clean_una(sk); 1403 mptcp_check_data_fin_ack(sk); 1404 __mptcp_flush_join_list(msk); 1405 __mptcp_move_skbs(msk); 1406 1407 if (msk->pm.status) 1408 pm_work(msk); 1409 1410 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 1411 mptcp_check_for_eof(msk); 1412 1413 mptcp_check_data_fin(sk); 1414 1415 if (!test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 1416 goto unlock; 1417 1418 dfrag = mptcp_rtx_head(sk); 1419 if (!dfrag) 1420 goto unlock; 1421 1422 if (!mptcp_ext_cache_refill(msk)) 1423 goto reset_unlock; 1424 1425 ssk = mptcp_subflow_get_retrans(msk); 1426 if (!ssk) 1427 goto reset_unlock; 1428 1429 lock_sock(ssk); 1430 1431 orig_len = dfrag->data_len; 1432 orig_offset = dfrag->offset; 1433 orig_write_seq = dfrag->data_seq; 1434 while (dfrag->data_len > 0) { 1435 int ret = mptcp_sendmsg_frag(sk, ssk, &msg, dfrag, &timeo, 1436 &mss_now, &size_goal); 1437 if (ret < 0) 1438 break; 1439 1440 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 1441 copied += ret; 1442 dfrag->data_len -= ret; 1443 dfrag->offset += ret; 1444 1445 if (!mptcp_ext_cache_refill(msk)) 1446 break; 1447 } 1448 if (copied) 1449 tcp_push(ssk, msg.msg_flags, mss_now, tcp_sk(ssk)->nonagle, 1450 size_goal); 1451 1452 dfrag->data_seq = orig_write_seq; 1453 dfrag->offset = orig_offset; 1454 dfrag->data_len = orig_len; 1455 1456 mptcp_set_timeout(sk, ssk); 1457 release_sock(ssk); 1458 1459 reset_unlock: 1460 if (!mptcp_timer_pending(sk)) 1461 mptcp_reset_timer(sk); 1462 1463 unlock: 1464 release_sock(sk); 1465 sock_put(sk); 1466 } 1467 1468 static int __mptcp_init_sock(struct sock *sk) 1469 { 1470 struct mptcp_sock *msk = mptcp_sk(sk); 1471 1472 spin_lock_init(&msk->join_list_lock); 1473 1474 INIT_LIST_HEAD(&msk->conn_list); 1475 INIT_LIST_HEAD(&msk->join_list); 1476 INIT_LIST_HEAD(&msk->rtx_queue); 1477 __set_bit(MPTCP_SEND_SPACE, &msk->flags); 1478 INIT_WORK(&msk->work, mptcp_worker); 1479 1480 msk->first = NULL; 1481 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 1482 1483 mptcp_pm_data_init(msk); 1484 1485 /* re-use the csk retrans timer for MPTCP-level retrans */ 1486 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 1487 1488 return 0; 1489 } 1490 1491 static int mptcp_init_sock(struct sock *sk) 1492 { 1493 struct net *net = sock_net(sk); 1494 int ret; 1495 1496 if (!mptcp_is_enabled(net)) 1497 return -ENOPROTOOPT; 1498 1499 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 1500 return -ENOMEM; 1501 1502 ret = __mptcp_init_sock(sk); 1503 if (ret) 1504 return ret; 1505 1506 ret = __mptcp_socket_create(mptcp_sk(sk)); 1507 if (ret) 1508 return ret; 1509 1510 sk_sockets_allocated_inc(sk); 1511 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1]; 1512 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[2]; 1513 1514 return 0; 1515 } 1516 1517 static void __mptcp_clear_xmit(struct sock *sk) 1518 { 1519 struct mptcp_sock *msk = mptcp_sk(sk); 1520 struct mptcp_data_frag *dtmp, *dfrag; 1521 1522 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); 1523 1524 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 1525 dfrag_clear(sk, dfrag); 1526 } 1527 1528 static void mptcp_cancel_work(struct sock *sk) 1529 { 1530 struct mptcp_sock *msk = mptcp_sk(sk); 1531 1532 if (cancel_work_sync(&msk->work)) 1533 sock_put(sk); 1534 } 1535 1536 static void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 1537 { 1538 lock_sock(ssk); 1539 1540 switch (ssk->sk_state) { 1541 case TCP_LISTEN: 1542 if (!(how & RCV_SHUTDOWN)) 1543 break; 1544 /* fall through */ 1545 case TCP_SYN_SENT: 1546 tcp_disconnect(ssk, O_NONBLOCK); 1547 break; 1548 default: 1549 if (__mptcp_check_fallback(mptcp_sk(sk))) { 1550 pr_debug("Fallback"); 1551 ssk->sk_shutdown |= how; 1552 tcp_shutdown(ssk, how); 1553 } else { 1554 pr_debug("Sending DATA_FIN on subflow %p", ssk); 1555 mptcp_set_timeout(sk, ssk); 1556 tcp_send_ack(ssk); 1557 } 1558 break; 1559 } 1560 1561 release_sock(ssk); 1562 } 1563 1564 static const unsigned char new_state[16] = { 1565 /* current state: new state: action: */ 1566 [0 /* (Invalid) */] = TCP_CLOSE, 1567 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1568 [TCP_SYN_SENT] = TCP_CLOSE, 1569 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 1570 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 1571 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 1572 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 1573 [TCP_CLOSE] = TCP_CLOSE, 1574 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 1575 [TCP_LAST_ACK] = TCP_LAST_ACK, 1576 [TCP_LISTEN] = TCP_CLOSE, 1577 [TCP_CLOSING] = TCP_CLOSING, 1578 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 1579 }; 1580 1581 static int mptcp_close_state(struct sock *sk) 1582 { 1583 int next = (int)new_state[sk->sk_state]; 1584 int ns = next & TCP_STATE_MASK; 1585 1586 inet_sk_state_store(sk, ns); 1587 1588 return next & TCP_ACTION_FIN; 1589 } 1590 1591 static void mptcp_close(struct sock *sk, long timeout) 1592 { 1593 struct mptcp_subflow_context *subflow, *tmp; 1594 struct mptcp_sock *msk = mptcp_sk(sk); 1595 LIST_HEAD(conn_list); 1596 1597 lock_sock(sk); 1598 sk->sk_shutdown = SHUTDOWN_MASK; 1599 1600 if (sk->sk_state == TCP_LISTEN) { 1601 inet_sk_state_store(sk, TCP_CLOSE); 1602 goto cleanup; 1603 } else if (sk->sk_state == TCP_CLOSE) { 1604 goto cleanup; 1605 } 1606 1607 if (__mptcp_check_fallback(msk)) { 1608 goto update_state; 1609 } else if (mptcp_close_state(sk)) { 1610 pr_debug("Sending DATA_FIN sk=%p", sk); 1611 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 1612 WRITE_ONCE(msk->snd_data_fin_enable, 1); 1613 1614 mptcp_for_each_subflow(msk, subflow) { 1615 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 1616 1617 mptcp_subflow_shutdown(sk, tcp_sk, SHUTDOWN_MASK); 1618 } 1619 } 1620 1621 sk_stream_wait_close(sk, timeout); 1622 1623 update_state: 1624 inet_sk_state_store(sk, TCP_CLOSE); 1625 1626 cleanup: 1627 /* be sure to always acquire the join list lock, to sync vs 1628 * mptcp_finish_join(). 1629 */ 1630 spin_lock_bh(&msk->join_list_lock); 1631 list_splice_tail_init(&msk->join_list, &msk->conn_list); 1632 spin_unlock_bh(&msk->join_list_lock); 1633 list_splice_init(&msk->conn_list, &conn_list); 1634 1635 __mptcp_clear_xmit(sk); 1636 1637 release_sock(sk); 1638 1639 list_for_each_entry_safe(subflow, tmp, &conn_list, node) { 1640 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1641 __mptcp_close_ssk(sk, ssk, subflow, timeout); 1642 } 1643 1644 mptcp_cancel_work(sk); 1645 1646 __skb_queue_purge(&sk->sk_receive_queue); 1647 1648 sk_common_release(sk); 1649 } 1650 1651 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 1652 { 1653 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1654 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 1655 struct ipv6_pinfo *msk6 = inet6_sk(msk); 1656 1657 msk->sk_v6_daddr = ssk->sk_v6_daddr; 1658 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 1659 1660 if (msk6 && ssk6) { 1661 msk6->saddr = ssk6->saddr; 1662 msk6->flow_label = ssk6->flow_label; 1663 } 1664 #endif 1665 1666 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 1667 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 1668 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 1669 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 1670 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 1671 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 1672 } 1673 1674 static int mptcp_disconnect(struct sock *sk, int flags) 1675 { 1676 /* Should never be called. 1677 * inet_stream_connect() calls ->disconnect, but that 1678 * refers to the subflow socket, not the mptcp one. 1679 */ 1680 WARN_ON_ONCE(1); 1681 return 0; 1682 } 1683 1684 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1685 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 1686 { 1687 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 1688 1689 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 1690 } 1691 #endif 1692 1693 struct sock *mptcp_sk_clone(const struct sock *sk, 1694 const struct mptcp_options_received *mp_opt, 1695 struct request_sock *req) 1696 { 1697 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 1698 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 1699 struct mptcp_sock *msk; 1700 u64 ack_seq; 1701 1702 if (!nsk) 1703 return NULL; 1704 1705 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 1706 if (nsk->sk_family == AF_INET6) 1707 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 1708 #endif 1709 1710 __mptcp_init_sock(nsk); 1711 1712 msk = mptcp_sk(nsk); 1713 msk->local_key = subflow_req->local_key; 1714 msk->token = subflow_req->token; 1715 msk->subflow = NULL; 1716 WRITE_ONCE(msk->fully_established, false); 1717 1718 msk->write_seq = subflow_req->idsn + 1; 1719 atomic64_set(&msk->snd_una, msk->write_seq); 1720 if (mp_opt->mp_capable) { 1721 msk->can_ack = true; 1722 msk->remote_key = mp_opt->sndr_key; 1723 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq); 1724 ack_seq++; 1725 msk->ack_seq = ack_seq; 1726 } 1727 1728 sock_reset_flag(nsk, SOCK_RCU_FREE); 1729 /* will be fully established after successful MPC subflow creation */ 1730 inet_sk_state_store(nsk, TCP_SYN_RECV); 1731 bh_unlock_sock(nsk); 1732 1733 /* keep a single reference */ 1734 __sock_put(nsk); 1735 return nsk; 1736 } 1737 1738 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 1739 { 1740 const struct tcp_sock *tp = tcp_sk(ssk); 1741 1742 msk->rcvq_space.copied = 0; 1743 msk->rcvq_space.rtt_us = 0; 1744 1745 msk->rcvq_space.time = tp->tcp_mstamp; 1746 1747 /* initial rcv_space offering made to peer */ 1748 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 1749 TCP_INIT_CWND * tp->advmss); 1750 if (msk->rcvq_space.space == 0) 1751 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 1752 } 1753 1754 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 1755 bool kern) 1756 { 1757 struct mptcp_sock *msk = mptcp_sk(sk); 1758 struct socket *listener; 1759 struct sock *newsk; 1760 1761 listener = __mptcp_nmpc_socket(msk); 1762 if (WARN_ON_ONCE(!listener)) { 1763 *err = -EINVAL; 1764 return NULL; 1765 } 1766 1767 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); 1768 newsk = inet_csk_accept(listener->sk, flags, err, kern); 1769 if (!newsk) 1770 return NULL; 1771 1772 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); 1773 if (sk_is_mptcp(newsk)) { 1774 struct mptcp_subflow_context *subflow; 1775 struct sock *new_mptcp_sock; 1776 struct sock *ssk = newsk; 1777 1778 subflow = mptcp_subflow_ctx(newsk); 1779 new_mptcp_sock = subflow->conn; 1780 1781 /* is_mptcp should be false if subflow->conn is missing, see 1782 * subflow_syn_recv_sock() 1783 */ 1784 if (WARN_ON_ONCE(!new_mptcp_sock)) { 1785 tcp_sk(newsk)->is_mptcp = 0; 1786 return newsk; 1787 } 1788 1789 /* acquire the 2nd reference for the owning socket */ 1790 sock_hold(new_mptcp_sock); 1791 1792 local_bh_disable(); 1793 bh_lock_sock(new_mptcp_sock); 1794 msk = mptcp_sk(new_mptcp_sock); 1795 msk->first = newsk; 1796 1797 newsk = new_mptcp_sock; 1798 mptcp_copy_inaddrs(newsk, ssk); 1799 list_add(&subflow->node, &msk->conn_list); 1800 1801 mptcp_rcv_space_init(msk, ssk); 1802 bh_unlock_sock(new_mptcp_sock); 1803 1804 __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 1805 local_bh_enable(); 1806 } else { 1807 MPTCP_INC_STATS(sock_net(sk), 1808 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 1809 } 1810 1811 return newsk; 1812 } 1813 1814 static void mptcp_destroy(struct sock *sk) 1815 { 1816 struct mptcp_sock *msk = mptcp_sk(sk); 1817 1818 mptcp_token_destroy(msk); 1819 if (msk->cached_ext) 1820 __skb_ext_put(msk->cached_ext); 1821 1822 sk_sockets_allocated_dec(sk); 1823 } 1824 1825 static int mptcp_setsockopt_sol_socket(struct mptcp_sock *msk, int optname, 1826 sockptr_t optval, unsigned int optlen) 1827 { 1828 struct sock *sk = (struct sock *)msk; 1829 struct socket *ssock; 1830 int ret; 1831 1832 switch (optname) { 1833 case SO_REUSEPORT: 1834 case SO_REUSEADDR: 1835 lock_sock(sk); 1836 ssock = __mptcp_nmpc_socket(msk); 1837 if (!ssock) { 1838 release_sock(sk); 1839 return -EINVAL; 1840 } 1841 1842 ret = sock_setsockopt(ssock, SOL_SOCKET, optname, optval, optlen); 1843 if (ret == 0) { 1844 if (optname == SO_REUSEPORT) 1845 sk->sk_reuseport = ssock->sk->sk_reuseport; 1846 else if (optname == SO_REUSEADDR) 1847 sk->sk_reuse = ssock->sk->sk_reuse; 1848 } 1849 release_sock(sk); 1850 return ret; 1851 } 1852 1853 return sock_setsockopt(sk->sk_socket, SOL_SOCKET, optname, optval, optlen); 1854 } 1855 1856 static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname, 1857 sockptr_t optval, unsigned int optlen) 1858 { 1859 struct sock *sk = (struct sock *)msk; 1860 int ret = -EOPNOTSUPP; 1861 struct socket *ssock; 1862 1863 switch (optname) { 1864 case IPV6_V6ONLY: 1865 lock_sock(sk); 1866 ssock = __mptcp_nmpc_socket(msk); 1867 if (!ssock) { 1868 release_sock(sk); 1869 return -EINVAL; 1870 } 1871 1872 ret = tcp_setsockopt(ssock->sk, SOL_IPV6, optname, optval, optlen); 1873 if (ret == 0) 1874 sk->sk_ipv6only = ssock->sk->sk_ipv6only; 1875 1876 release_sock(sk); 1877 break; 1878 } 1879 1880 return ret; 1881 } 1882 1883 static int mptcp_setsockopt(struct sock *sk, int level, int optname, 1884 sockptr_t optval, unsigned int optlen) 1885 { 1886 struct mptcp_sock *msk = mptcp_sk(sk); 1887 struct sock *ssk; 1888 1889 pr_debug("msk=%p", msk); 1890 1891 if (level == SOL_SOCKET) 1892 return mptcp_setsockopt_sol_socket(msk, optname, optval, optlen); 1893 1894 /* @@ the meaning of setsockopt() when the socket is connected and 1895 * there are multiple subflows is not yet defined. It is up to the 1896 * MPTCP-level socket to configure the subflows until the subflow 1897 * is in TCP fallback, when TCP socket options are passed through 1898 * to the one remaining subflow. 1899 */ 1900 lock_sock(sk); 1901 ssk = __mptcp_tcp_fallback(msk); 1902 release_sock(sk); 1903 if (ssk) 1904 return tcp_setsockopt(ssk, level, optname, optval, optlen); 1905 1906 if (level == SOL_IPV6) 1907 return mptcp_setsockopt_v6(msk, optname, optval, optlen); 1908 1909 return -EOPNOTSUPP; 1910 } 1911 1912 static int mptcp_getsockopt(struct sock *sk, int level, int optname, 1913 char __user *optval, int __user *option) 1914 { 1915 struct mptcp_sock *msk = mptcp_sk(sk); 1916 struct sock *ssk; 1917 1918 pr_debug("msk=%p", msk); 1919 1920 /* @@ the meaning of setsockopt() when the socket is connected and 1921 * there are multiple subflows is not yet defined. It is up to the 1922 * MPTCP-level socket to configure the subflows until the subflow 1923 * is in TCP fallback, when socket options are passed through 1924 * to the one remaining subflow. 1925 */ 1926 lock_sock(sk); 1927 ssk = __mptcp_tcp_fallback(msk); 1928 release_sock(sk); 1929 if (ssk) 1930 return tcp_getsockopt(ssk, level, optname, optval, option); 1931 1932 return -EOPNOTSUPP; 1933 } 1934 1935 #define MPTCP_DEFERRED_ALL (TCPF_DELACK_TIMER_DEFERRED | \ 1936 TCPF_WRITE_TIMER_DEFERRED) 1937 1938 /* this is very alike tcp_release_cb() but we must handle differently a 1939 * different set of events 1940 */ 1941 static void mptcp_release_cb(struct sock *sk) 1942 { 1943 unsigned long flags, nflags; 1944 1945 do { 1946 flags = sk->sk_tsq_flags; 1947 if (!(flags & MPTCP_DEFERRED_ALL)) 1948 return; 1949 nflags = flags & ~MPTCP_DEFERRED_ALL; 1950 } while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags); 1951 1952 sock_release_ownership(sk); 1953 1954 if (flags & TCPF_DELACK_TIMER_DEFERRED) { 1955 struct mptcp_sock *msk = mptcp_sk(sk); 1956 struct sock *ssk; 1957 1958 ssk = mptcp_subflow_recv_lookup(msk); 1959 if (!ssk || !schedule_work(&msk->work)) 1960 __sock_put(sk); 1961 } 1962 1963 if (flags & TCPF_WRITE_TIMER_DEFERRED) { 1964 mptcp_retransmit_handler(sk); 1965 __sock_put(sk); 1966 } 1967 } 1968 1969 static int mptcp_hash(struct sock *sk) 1970 { 1971 /* should never be called, 1972 * we hash the TCP subflows not the master socket 1973 */ 1974 WARN_ON_ONCE(1); 1975 return 0; 1976 } 1977 1978 static void mptcp_unhash(struct sock *sk) 1979 { 1980 /* called from sk_common_release(), but nothing to do here */ 1981 } 1982 1983 static int mptcp_get_port(struct sock *sk, unsigned short snum) 1984 { 1985 struct mptcp_sock *msk = mptcp_sk(sk); 1986 struct socket *ssock; 1987 1988 ssock = __mptcp_nmpc_socket(msk); 1989 pr_debug("msk=%p, subflow=%p", msk, ssock); 1990 if (WARN_ON_ONCE(!ssock)) 1991 return -EINVAL; 1992 1993 return inet_csk_get_port(ssock->sk, snum); 1994 } 1995 1996 void mptcp_finish_connect(struct sock *ssk) 1997 { 1998 struct mptcp_subflow_context *subflow; 1999 struct mptcp_sock *msk; 2000 struct sock *sk; 2001 u64 ack_seq; 2002 2003 subflow = mptcp_subflow_ctx(ssk); 2004 sk = subflow->conn; 2005 msk = mptcp_sk(sk); 2006 2007 pr_debug("msk=%p, token=%u", sk, subflow->token); 2008 2009 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq); 2010 ack_seq++; 2011 subflow->map_seq = ack_seq; 2012 subflow->map_subflow_seq = 1; 2013 2014 /* the socket is not connected yet, no msk/subflow ops can access/race 2015 * accessing the field below 2016 */ 2017 WRITE_ONCE(msk->remote_key, subflow->remote_key); 2018 WRITE_ONCE(msk->local_key, subflow->local_key); 2019 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 2020 WRITE_ONCE(msk->ack_seq, ack_seq); 2021 WRITE_ONCE(msk->can_ack, 1); 2022 atomic64_set(&msk->snd_una, msk->write_seq); 2023 2024 mptcp_pm_new_connection(msk, 0); 2025 2026 mptcp_rcv_space_init(msk, ssk); 2027 } 2028 2029 static void mptcp_sock_graft(struct sock *sk, struct socket *parent) 2030 { 2031 write_lock_bh(&sk->sk_callback_lock); 2032 rcu_assign_pointer(sk->sk_wq, &parent->wq); 2033 sk_set_socket(sk, parent); 2034 sk->sk_uid = SOCK_INODE(parent)->i_uid; 2035 write_unlock_bh(&sk->sk_callback_lock); 2036 } 2037 2038 bool mptcp_finish_join(struct sock *sk) 2039 { 2040 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 2041 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 2042 struct sock *parent = (void *)msk; 2043 struct socket *parent_sock; 2044 bool ret; 2045 2046 pr_debug("msk=%p, subflow=%p", msk, subflow); 2047 2048 /* mptcp socket already closing? */ 2049 if (!mptcp_is_fully_established(parent)) 2050 return false; 2051 2052 if (!msk->pm.server_side) 2053 return true; 2054 2055 if (!mptcp_pm_allow_new_subflow(msk)) 2056 return false; 2057 2058 /* active connections are already on conn_list, and we can't acquire 2059 * msk lock here. 2060 * use the join list lock as synchronization point and double-check 2061 * msk status to avoid racing with mptcp_close() 2062 */ 2063 spin_lock_bh(&msk->join_list_lock); 2064 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED; 2065 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) 2066 list_add_tail(&subflow->node, &msk->join_list); 2067 spin_unlock_bh(&msk->join_list_lock); 2068 if (!ret) 2069 return false; 2070 2071 /* attach to msk socket only after we are sure he will deal with us 2072 * at close time 2073 */ 2074 parent_sock = READ_ONCE(parent->sk_socket); 2075 if (parent_sock && !sk->sk_socket) 2076 mptcp_sock_graft(sk, parent_sock); 2077 subflow->map_seq = msk->ack_seq; 2078 return true; 2079 } 2080 2081 static bool mptcp_memory_free(const struct sock *sk, int wake) 2082 { 2083 struct mptcp_sock *msk = mptcp_sk(sk); 2084 2085 return wake ? test_bit(MPTCP_SEND_SPACE, &msk->flags) : true; 2086 } 2087 2088 static struct proto mptcp_prot = { 2089 .name = "MPTCP", 2090 .owner = THIS_MODULE, 2091 .init = mptcp_init_sock, 2092 .disconnect = mptcp_disconnect, 2093 .close = mptcp_close, 2094 .accept = mptcp_accept, 2095 .setsockopt = mptcp_setsockopt, 2096 .getsockopt = mptcp_getsockopt, 2097 .shutdown = tcp_shutdown, 2098 .destroy = mptcp_destroy, 2099 .sendmsg = mptcp_sendmsg, 2100 .recvmsg = mptcp_recvmsg, 2101 .release_cb = mptcp_release_cb, 2102 .hash = mptcp_hash, 2103 .unhash = mptcp_unhash, 2104 .get_port = mptcp_get_port, 2105 .sockets_allocated = &mptcp_sockets_allocated, 2106 .memory_allocated = &tcp_memory_allocated, 2107 .memory_pressure = &tcp_memory_pressure, 2108 .stream_memory_free = mptcp_memory_free, 2109 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 2110 .sysctl_mem = sysctl_tcp_mem, 2111 .obj_size = sizeof(struct mptcp_sock), 2112 .slab_flags = SLAB_TYPESAFE_BY_RCU, 2113 .no_autobind = true, 2114 }; 2115 2116 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 2117 { 2118 struct mptcp_sock *msk = mptcp_sk(sock->sk); 2119 struct socket *ssock; 2120 int err; 2121 2122 lock_sock(sock->sk); 2123 ssock = __mptcp_nmpc_socket(msk); 2124 if (!ssock) { 2125 err = -EINVAL; 2126 goto unlock; 2127 } 2128 2129 err = ssock->ops->bind(ssock, uaddr, addr_len); 2130 if (!err) 2131 mptcp_copy_inaddrs(sock->sk, ssock->sk); 2132 2133 unlock: 2134 release_sock(sock->sk); 2135 return err; 2136 } 2137 2138 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 2139 struct mptcp_subflow_context *subflow) 2140 { 2141 subflow->request_mptcp = 0; 2142 __mptcp_do_fallback(msk); 2143 } 2144 2145 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, 2146 int addr_len, int flags) 2147 { 2148 struct mptcp_sock *msk = mptcp_sk(sock->sk); 2149 struct mptcp_subflow_context *subflow; 2150 struct socket *ssock; 2151 int err; 2152 2153 lock_sock(sock->sk); 2154 if (sock->state != SS_UNCONNECTED && msk->subflow) { 2155 /* pending connection or invalid state, let existing subflow 2156 * cope with that 2157 */ 2158 ssock = msk->subflow; 2159 goto do_connect; 2160 } 2161 2162 ssock = __mptcp_nmpc_socket(msk); 2163 if (!ssock) { 2164 err = -EINVAL; 2165 goto unlock; 2166 } 2167 2168 mptcp_token_destroy(msk); 2169 inet_sk_state_store(sock->sk, TCP_SYN_SENT); 2170 subflow = mptcp_subflow_ctx(ssock->sk); 2171 #ifdef CONFIG_TCP_MD5SIG 2172 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 2173 * TCP option space. 2174 */ 2175 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info)) 2176 mptcp_subflow_early_fallback(msk, subflow); 2177 #endif 2178 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) 2179 mptcp_subflow_early_fallback(msk, subflow); 2180 2181 do_connect: 2182 err = ssock->ops->connect(ssock, uaddr, addr_len, flags); 2183 sock->state = ssock->state; 2184 2185 /* on successful connect, the msk state will be moved to established by 2186 * subflow_finish_connect() 2187 */ 2188 if (!err || err == -EINPROGRESS) 2189 mptcp_copy_inaddrs(sock->sk, ssock->sk); 2190 else 2191 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 2192 2193 unlock: 2194 release_sock(sock->sk); 2195 return err; 2196 } 2197 2198 static int mptcp_listen(struct socket *sock, int backlog) 2199 { 2200 struct mptcp_sock *msk = mptcp_sk(sock->sk); 2201 struct socket *ssock; 2202 int err; 2203 2204 pr_debug("msk=%p", msk); 2205 2206 lock_sock(sock->sk); 2207 ssock = __mptcp_nmpc_socket(msk); 2208 if (!ssock) { 2209 err = -EINVAL; 2210 goto unlock; 2211 } 2212 2213 mptcp_token_destroy(msk); 2214 inet_sk_state_store(sock->sk, TCP_LISTEN); 2215 sock_set_flag(sock->sk, SOCK_RCU_FREE); 2216 2217 err = ssock->ops->listen(ssock, backlog); 2218 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 2219 if (!err) 2220 mptcp_copy_inaddrs(sock->sk, ssock->sk); 2221 2222 unlock: 2223 release_sock(sock->sk); 2224 return err; 2225 } 2226 2227 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 2228 int flags, bool kern) 2229 { 2230 struct mptcp_sock *msk = mptcp_sk(sock->sk); 2231 struct socket *ssock; 2232 int err; 2233 2234 pr_debug("msk=%p", msk); 2235 2236 lock_sock(sock->sk); 2237 if (sock->sk->sk_state != TCP_LISTEN) 2238 goto unlock_fail; 2239 2240 ssock = __mptcp_nmpc_socket(msk); 2241 if (!ssock) 2242 goto unlock_fail; 2243 2244 clear_bit(MPTCP_DATA_READY, &msk->flags); 2245 sock_hold(ssock->sk); 2246 release_sock(sock->sk); 2247 2248 err = ssock->ops->accept(sock, newsock, flags, kern); 2249 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { 2250 struct mptcp_sock *msk = mptcp_sk(newsock->sk); 2251 struct mptcp_subflow_context *subflow; 2252 2253 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 2254 * This is needed so NOSPACE flag can be set from tcp stack. 2255 */ 2256 __mptcp_flush_join_list(msk); 2257 mptcp_for_each_subflow(msk, subflow) { 2258 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2259 2260 if (!ssk->sk_socket) 2261 mptcp_sock_graft(ssk, newsock); 2262 } 2263 } 2264 2265 if (inet_csk_listen_poll(ssock->sk)) 2266 set_bit(MPTCP_DATA_READY, &msk->flags); 2267 sock_put(ssock->sk); 2268 return err; 2269 2270 unlock_fail: 2271 release_sock(sock->sk); 2272 return -EINVAL; 2273 } 2274 2275 static __poll_t mptcp_check_readable(struct mptcp_sock *msk) 2276 { 2277 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 2278 0; 2279 } 2280 2281 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 2282 struct poll_table_struct *wait) 2283 { 2284 struct sock *sk = sock->sk; 2285 struct mptcp_sock *msk; 2286 __poll_t mask = 0; 2287 int state; 2288 2289 msk = mptcp_sk(sk); 2290 sock_poll_wait(file, sock, wait); 2291 2292 state = inet_sk_state_load(sk); 2293 if (state == TCP_LISTEN) 2294 return mptcp_check_readable(msk); 2295 2296 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 2297 mask |= mptcp_check_readable(msk); 2298 if (sk_stream_is_writeable(sk) && 2299 test_bit(MPTCP_SEND_SPACE, &msk->flags)) 2300 mask |= EPOLLOUT | EPOLLWRNORM; 2301 } 2302 if (sk->sk_shutdown & RCV_SHUTDOWN) 2303 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 2304 2305 return mask; 2306 } 2307 2308 static int mptcp_shutdown(struct socket *sock, int how) 2309 { 2310 struct mptcp_sock *msk = mptcp_sk(sock->sk); 2311 struct mptcp_subflow_context *subflow; 2312 int ret = 0; 2313 2314 pr_debug("sk=%p, how=%d", msk, how); 2315 2316 lock_sock(sock->sk); 2317 2318 how++; 2319 if ((how & ~SHUTDOWN_MASK) || !how) { 2320 ret = -EINVAL; 2321 goto out_unlock; 2322 } 2323 2324 if (sock->state == SS_CONNECTING) { 2325 if ((1 << sock->sk->sk_state) & 2326 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)) 2327 sock->state = SS_DISCONNECTING; 2328 else 2329 sock->state = SS_CONNECTED; 2330 } 2331 2332 /* If we've already sent a FIN, or it's a closed state, skip this. */ 2333 if (__mptcp_check_fallback(msk)) { 2334 if (how == SHUT_WR || how == SHUT_RDWR) 2335 inet_sk_state_store(sock->sk, TCP_FIN_WAIT1); 2336 2337 mptcp_for_each_subflow(msk, subflow) { 2338 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2339 2340 mptcp_subflow_shutdown(sock->sk, tcp_sk, how); 2341 } 2342 } else if ((how & SEND_SHUTDOWN) && 2343 ((1 << sock->sk->sk_state) & 2344 (TCPF_ESTABLISHED | TCPF_SYN_SENT | 2345 TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) && 2346 mptcp_close_state(sock->sk)) { 2347 __mptcp_flush_join_list(msk); 2348 2349 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2350 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2351 2352 mptcp_for_each_subflow(msk, subflow) { 2353 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2354 2355 mptcp_subflow_shutdown(sock->sk, tcp_sk, how); 2356 } 2357 } 2358 2359 /* Wake up anyone sleeping in poll. */ 2360 sock->sk->sk_state_change(sock->sk); 2361 2362 out_unlock: 2363 release_sock(sock->sk); 2364 2365 return ret; 2366 } 2367 2368 static const struct proto_ops mptcp_stream_ops = { 2369 .family = PF_INET, 2370 .owner = THIS_MODULE, 2371 .release = inet_release, 2372 .bind = mptcp_bind, 2373 .connect = mptcp_stream_connect, 2374 .socketpair = sock_no_socketpair, 2375 .accept = mptcp_stream_accept, 2376 .getname = inet_getname, 2377 .poll = mptcp_poll, 2378 .ioctl = inet_ioctl, 2379 .gettstamp = sock_gettstamp, 2380 .listen = mptcp_listen, 2381 .shutdown = mptcp_shutdown, 2382 .setsockopt = sock_common_setsockopt, 2383 .getsockopt = sock_common_getsockopt, 2384 .sendmsg = inet_sendmsg, 2385 .recvmsg = inet_recvmsg, 2386 .mmap = sock_no_mmap, 2387 .sendpage = inet_sendpage, 2388 }; 2389 2390 static struct inet_protosw mptcp_protosw = { 2391 .type = SOCK_STREAM, 2392 .protocol = IPPROTO_MPTCP, 2393 .prot = &mptcp_prot, 2394 .ops = &mptcp_stream_ops, 2395 .flags = INET_PROTOSW_ICSK, 2396 }; 2397 2398 void __init mptcp_proto_init(void) 2399 { 2400 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 2401 2402 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 2403 panic("Failed to allocate MPTCP pcpu counter\n"); 2404 2405 mptcp_subflow_init(); 2406 mptcp_pm_init(); 2407 mptcp_token_init(); 2408 2409 if (proto_register(&mptcp_prot, 1) != 0) 2410 panic("Failed to register MPTCP proto.\n"); 2411 2412 inet_register_protosw(&mptcp_protosw); 2413 2414 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 2415 } 2416 2417 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2418 static const struct proto_ops mptcp_v6_stream_ops = { 2419 .family = PF_INET6, 2420 .owner = THIS_MODULE, 2421 .release = inet6_release, 2422 .bind = mptcp_bind, 2423 .connect = mptcp_stream_connect, 2424 .socketpair = sock_no_socketpair, 2425 .accept = mptcp_stream_accept, 2426 .getname = inet6_getname, 2427 .poll = mptcp_poll, 2428 .ioctl = inet6_ioctl, 2429 .gettstamp = sock_gettstamp, 2430 .listen = mptcp_listen, 2431 .shutdown = mptcp_shutdown, 2432 .setsockopt = sock_common_setsockopt, 2433 .getsockopt = sock_common_getsockopt, 2434 .sendmsg = inet6_sendmsg, 2435 .recvmsg = inet6_recvmsg, 2436 .mmap = sock_no_mmap, 2437 .sendpage = inet_sendpage, 2438 #ifdef CONFIG_COMPAT 2439 .compat_ioctl = inet6_compat_ioctl, 2440 #endif 2441 }; 2442 2443 static struct proto mptcp_v6_prot; 2444 2445 static void mptcp_v6_destroy(struct sock *sk) 2446 { 2447 mptcp_destroy(sk); 2448 inet6_destroy_sock(sk); 2449 } 2450 2451 static struct inet_protosw mptcp_v6_protosw = { 2452 .type = SOCK_STREAM, 2453 .protocol = IPPROTO_MPTCP, 2454 .prot = &mptcp_v6_prot, 2455 .ops = &mptcp_v6_stream_ops, 2456 .flags = INET_PROTOSW_ICSK, 2457 }; 2458 2459 int __init mptcp_proto_v6_init(void) 2460 { 2461 int err; 2462 2463 mptcp_v6_prot = mptcp_prot; 2464 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 2465 mptcp_v6_prot.slab = NULL; 2466 mptcp_v6_prot.destroy = mptcp_v6_destroy; 2467 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 2468 2469 err = proto_register(&mptcp_v6_prot, 1); 2470 if (err) 2471 return err; 2472 2473 err = inet6_register_protosw(&mptcp_v6_protosw); 2474 if (err) 2475 proto_unregister(&mptcp_v6_prot); 2476 2477 return err; 2478 } 2479 #endif 2480