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 <net/xfrm.h> 25 #include "protocol.h" 26 #include "mib.h" 27 28 #define CREATE_TRACE_POINTS 29 #include <trace/events/mptcp.h> 30 31 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 32 struct mptcp6_sock { 33 struct mptcp_sock msk; 34 struct ipv6_pinfo np; 35 }; 36 #endif 37 38 struct mptcp_skb_cb { 39 u64 map_seq; 40 u64 end_seq; 41 u32 offset; 42 u8 has_rxtstamp:1; 43 }; 44 45 #define MPTCP_SKB_CB(__skb) ((struct mptcp_skb_cb *)&((__skb)->cb[0])) 46 47 enum { 48 MPTCP_CMSG_TS = BIT(0), 49 }; 50 51 static struct percpu_counter mptcp_sockets_allocated; 52 53 static void __mptcp_destroy_sock(struct sock *sk); 54 static void __mptcp_check_send_data_fin(struct sock *sk); 55 56 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); 57 static struct net_device mptcp_napi_dev; 58 59 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not 60 * completed yet or has failed, return the subflow socket. 61 * Otherwise return NULL. 62 */ 63 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) 64 { 65 if (!msk->subflow || READ_ONCE(msk->can_ack)) 66 return NULL; 67 68 return msk->subflow; 69 } 70 71 /* Returns end sequence number of the receiver's advertised window */ 72 static u64 mptcp_wnd_end(const struct mptcp_sock *msk) 73 { 74 return READ_ONCE(msk->wnd_end); 75 } 76 77 static bool mptcp_is_tcpsk(struct sock *sk) 78 { 79 struct socket *sock = sk->sk_socket; 80 81 if (unlikely(sk->sk_prot == &tcp_prot)) { 82 /* we are being invoked after mptcp_accept() has 83 * accepted a non-mp-capable flow: sk is a tcp_sk, 84 * not an mptcp one. 85 * 86 * Hand the socket over to tcp so all further socket ops 87 * bypass mptcp. 88 */ 89 sock->ops = &inet_stream_ops; 90 return true; 91 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 92 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { 93 sock->ops = &inet6_stream_ops; 94 return true; 95 #endif 96 } 97 98 return false; 99 } 100 101 static int __mptcp_socket_create(struct mptcp_sock *msk) 102 { 103 struct mptcp_subflow_context *subflow; 104 struct sock *sk = (struct sock *)msk; 105 struct socket *ssock; 106 int err; 107 108 err = mptcp_subflow_create_socket(sk, &ssock); 109 if (err) 110 return err; 111 112 msk->first = ssock->sk; 113 msk->subflow = ssock; 114 subflow = mptcp_subflow_ctx(ssock->sk); 115 list_add(&subflow->node, &msk->conn_list); 116 sock_hold(ssock->sk); 117 subflow->request_mptcp = 1; 118 mptcp_sock_graft(msk->first, sk->sk_socket); 119 120 return 0; 121 } 122 123 static void mptcp_drop(struct sock *sk, struct sk_buff *skb) 124 { 125 sk_drops_add(sk, skb); 126 __kfree_skb(skb); 127 } 128 129 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, 130 struct sk_buff *from) 131 { 132 bool fragstolen; 133 int delta; 134 135 if (MPTCP_SKB_CB(from)->offset || 136 !skb_try_coalesce(to, from, &fragstolen, &delta)) 137 return false; 138 139 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", 140 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, 141 to->len, MPTCP_SKB_CB(from)->end_seq); 142 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; 143 kfree_skb_partial(from, fragstolen); 144 atomic_add(delta, &sk->sk_rmem_alloc); 145 sk_mem_charge(sk, delta); 146 return true; 147 } 148 149 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, 150 struct sk_buff *from) 151 { 152 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) 153 return false; 154 155 return mptcp_try_coalesce((struct sock *)msk, to, from); 156 } 157 158 /* "inspired" by tcp_data_queue_ofo(), main differences: 159 * - use mptcp seqs 160 * - don't cope with sacks 161 */ 162 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) 163 { 164 struct sock *sk = (struct sock *)msk; 165 struct rb_node **p, *parent; 166 u64 seq, end_seq, max_seq; 167 struct sk_buff *skb1; 168 169 seq = MPTCP_SKB_CB(skb)->map_seq; 170 end_seq = MPTCP_SKB_CB(skb)->end_seq; 171 max_seq = READ_ONCE(msk->rcv_wnd_sent); 172 173 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, 174 RB_EMPTY_ROOT(&msk->out_of_order_queue)); 175 if (after64(end_seq, max_seq)) { 176 /* out of window */ 177 mptcp_drop(sk, skb); 178 pr_debug("oow by %lld, rcv_wnd_sent %llu\n", 179 (unsigned long long)end_seq - (unsigned long)max_seq, 180 (unsigned long long)msk->rcv_wnd_sent); 181 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); 182 return; 183 } 184 185 p = &msk->out_of_order_queue.rb_node; 186 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); 187 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { 188 rb_link_node(&skb->rbnode, NULL, p); 189 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 190 msk->ooo_last_skb = skb; 191 goto end; 192 } 193 194 /* with 2 subflows, adding at end of ooo queue is quite likely 195 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. 196 */ 197 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { 198 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 199 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 200 return; 201 } 202 203 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ 204 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { 205 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 206 parent = &msk->ooo_last_skb->rbnode; 207 p = &parent->rb_right; 208 goto insert; 209 } 210 211 /* Find place to insert this segment. Handle overlaps on the way. */ 212 parent = NULL; 213 while (*p) { 214 parent = *p; 215 skb1 = rb_to_skb(parent); 216 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 217 p = &parent->rb_left; 218 continue; 219 } 220 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { 221 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { 222 /* All the bits are present. Drop. */ 223 mptcp_drop(sk, skb); 224 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 225 return; 226 } 227 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 228 /* partial overlap: 229 * | skb | 230 * | skb1 | 231 * continue traversing 232 */ 233 } else { 234 /* skb's seq == skb1's seq and skb covers skb1. 235 * Replace skb1 with skb. 236 */ 237 rb_replace_node(&skb1->rbnode, &skb->rbnode, 238 &msk->out_of_order_queue); 239 mptcp_drop(sk, skb1); 240 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 241 goto merge_right; 242 } 243 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { 244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 245 return; 246 } 247 p = &parent->rb_right; 248 } 249 250 insert: 251 /* Insert segment into RB tree. */ 252 rb_link_node(&skb->rbnode, parent, p); 253 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 254 255 merge_right: 256 /* Remove other segments covered by skb. */ 257 while ((skb1 = skb_rb_next(skb)) != NULL) { 258 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) 259 break; 260 rb_erase(&skb1->rbnode, &msk->out_of_order_queue); 261 mptcp_drop(sk, skb1); 262 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 263 } 264 /* If there is no skb after us, we are the last_skb ! */ 265 if (!skb1) 266 msk->ooo_last_skb = skb; 267 268 end: 269 skb_condense(skb); 270 skb_set_owner_r(skb, sk); 271 } 272 273 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 274 struct sk_buff *skb, unsigned int offset, 275 size_t copy_len) 276 { 277 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 278 struct sock *sk = (struct sock *)msk; 279 struct sk_buff *tail; 280 bool has_rxtstamp; 281 282 __skb_unlink(skb, &ssk->sk_receive_queue); 283 284 skb_ext_reset(skb); 285 skb_orphan(skb); 286 287 /* try to fetch required memory from subflow */ 288 if (!sk_rmem_schedule(sk, skb, skb->truesize)) { 289 if (ssk->sk_forward_alloc < skb->truesize) 290 goto drop; 291 __sk_mem_reclaim(ssk, skb->truesize); 292 if (!sk_rmem_schedule(sk, skb, skb->truesize)) 293 goto drop; 294 } 295 296 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; 297 298 /* the skb map_seq accounts for the skb offset: 299 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq 300 * value 301 */ 302 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); 303 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; 304 MPTCP_SKB_CB(skb)->offset = offset; 305 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; 306 307 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { 308 /* in sequence */ 309 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); 310 tail = skb_peek_tail(&sk->sk_receive_queue); 311 if (tail && mptcp_try_coalesce(sk, tail, skb)) 312 return true; 313 314 skb_set_owner_r(skb, sk); 315 __skb_queue_tail(&sk->sk_receive_queue, skb); 316 return true; 317 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { 318 mptcp_data_queue_ofo(msk, skb); 319 return false; 320 } 321 322 /* old data, keep it simple and drop the whole pkt, sender 323 * will retransmit as needed, if needed. 324 */ 325 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 326 drop: 327 mptcp_drop(sk, skb); 328 return false; 329 } 330 331 static void mptcp_stop_timer(struct sock *sk) 332 { 333 struct inet_connection_sock *icsk = inet_csk(sk); 334 335 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 336 mptcp_sk(sk)->timer_ival = 0; 337 } 338 339 static void mptcp_close_wake_up(struct sock *sk) 340 { 341 if (sock_flag(sk, SOCK_DEAD)) 342 return; 343 344 sk->sk_state_change(sk); 345 if (sk->sk_shutdown == SHUTDOWN_MASK || 346 sk->sk_state == TCP_CLOSE) 347 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 348 else 349 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 350 } 351 352 static bool mptcp_pending_data_fin_ack(struct sock *sk) 353 { 354 struct mptcp_sock *msk = mptcp_sk(sk); 355 356 return !__mptcp_check_fallback(msk) && 357 ((1 << sk->sk_state) & 358 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && 359 msk->write_seq == READ_ONCE(msk->snd_una); 360 } 361 362 static void mptcp_check_data_fin_ack(struct sock *sk) 363 { 364 struct mptcp_sock *msk = mptcp_sk(sk); 365 366 /* Look for an acknowledged DATA_FIN */ 367 if (mptcp_pending_data_fin_ack(sk)) { 368 WRITE_ONCE(msk->snd_data_fin_enable, 0); 369 370 switch (sk->sk_state) { 371 case TCP_FIN_WAIT1: 372 inet_sk_state_store(sk, TCP_FIN_WAIT2); 373 break; 374 case TCP_CLOSING: 375 case TCP_LAST_ACK: 376 inet_sk_state_store(sk, TCP_CLOSE); 377 break; 378 } 379 380 mptcp_close_wake_up(sk); 381 } 382 } 383 384 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 385 { 386 struct mptcp_sock *msk = mptcp_sk(sk); 387 388 if (READ_ONCE(msk->rcv_data_fin) && 389 ((1 << sk->sk_state) & 390 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { 391 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); 392 393 if (msk->ack_seq == rcv_data_fin_seq) { 394 if (seq) 395 *seq = rcv_data_fin_seq; 396 397 return true; 398 } 399 } 400 401 return false; 402 } 403 404 static void mptcp_set_datafin_timeout(const struct sock *sk) 405 { 406 struct inet_connection_sock *icsk = inet_csk(sk); 407 408 mptcp_sk(sk)->timer_ival = min(TCP_RTO_MAX, 409 TCP_RTO_MIN << icsk->icsk_retransmits); 410 } 411 412 static void mptcp_set_timeout(const struct sock *sk, const struct sock *ssk) 413 { 414 long tout = ssk && inet_csk(ssk)->icsk_pending ? 415 inet_csk(ssk)->icsk_timeout - jiffies : 0; 416 417 if (tout <= 0) 418 tout = mptcp_sk(sk)->timer_ival; 419 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; 420 } 421 422 static bool tcp_can_send_ack(const struct sock *ssk) 423 { 424 return !((1 << inet_sk_state_load(ssk)) & 425 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); 426 } 427 428 static void mptcp_send_ack(struct mptcp_sock *msk) 429 { 430 struct mptcp_subflow_context *subflow; 431 432 mptcp_for_each_subflow(msk, subflow) { 433 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 434 435 lock_sock(ssk); 436 if (tcp_can_send_ack(ssk)) 437 tcp_send_ack(ssk); 438 release_sock(ssk); 439 } 440 } 441 442 static bool mptcp_subflow_cleanup_rbuf(struct sock *ssk) 443 { 444 int ret; 445 446 lock_sock(ssk); 447 ret = tcp_can_send_ack(ssk); 448 if (ret) 449 tcp_cleanup_rbuf(ssk, 1); 450 release_sock(ssk); 451 return ret; 452 } 453 454 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) 455 { 456 struct sock *ack_hint = READ_ONCE(msk->ack_hint); 457 int old_space = READ_ONCE(msk->old_wspace); 458 struct mptcp_subflow_context *subflow; 459 struct sock *sk = (struct sock *)msk; 460 bool cleanup; 461 462 /* this is a simple superset of what tcp_cleanup_rbuf() implements 463 * so that we don't have to acquire the ssk socket lock most of the time 464 * to do actually nothing 465 */ 466 cleanup = __mptcp_space(sk) - old_space >= max(0, old_space); 467 if (!cleanup) 468 return; 469 470 /* if the hinted ssk is still active, try to use it */ 471 if (likely(ack_hint)) { 472 mptcp_for_each_subflow(msk, subflow) { 473 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 474 475 if (ack_hint == ssk && mptcp_subflow_cleanup_rbuf(ssk)) 476 return; 477 } 478 } 479 480 /* otherwise pick the first active subflow */ 481 mptcp_for_each_subflow(msk, subflow) 482 if (mptcp_subflow_cleanup_rbuf(mptcp_subflow_tcp_sock(subflow))) 483 return; 484 } 485 486 static bool mptcp_check_data_fin(struct sock *sk) 487 { 488 struct mptcp_sock *msk = mptcp_sk(sk); 489 u64 rcv_data_fin_seq; 490 bool ret = false; 491 492 if (__mptcp_check_fallback(msk)) 493 return ret; 494 495 /* Need to ack a DATA_FIN received from a peer while this side 496 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. 497 * msk->rcv_data_fin was set when parsing the incoming options 498 * at the subflow level and the msk lock was not held, so this 499 * is the first opportunity to act on the DATA_FIN and change 500 * the msk state. 501 * 502 * If we are caught up to the sequence number of the incoming 503 * DATA_FIN, send the DATA_ACK now and do state transition. If 504 * not caught up, do nothing and let the recv code send DATA_ACK 505 * when catching up. 506 */ 507 508 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { 509 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); 510 WRITE_ONCE(msk->rcv_data_fin, 0); 511 512 sk->sk_shutdown |= RCV_SHUTDOWN; 513 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 514 set_bit(MPTCP_DATA_READY, &msk->flags); 515 516 switch (sk->sk_state) { 517 case TCP_ESTABLISHED: 518 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 519 break; 520 case TCP_FIN_WAIT1: 521 inet_sk_state_store(sk, TCP_CLOSING); 522 break; 523 case TCP_FIN_WAIT2: 524 inet_sk_state_store(sk, TCP_CLOSE); 525 break; 526 default: 527 /* Other states not expected */ 528 WARN_ON_ONCE(1); 529 break; 530 } 531 532 ret = true; 533 mptcp_set_timeout(sk, NULL); 534 mptcp_send_ack(msk); 535 mptcp_close_wake_up(sk); 536 } 537 return ret; 538 } 539 540 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 541 struct sock *ssk, 542 unsigned int *bytes) 543 { 544 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 545 struct sock *sk = (struct sock *)msk; 546 unsigned int moved = 0; 547 bool more_data_avail; 548 struct tcp_sock *tp; 549 bool done = false; 550 int sk_rbuf; 551 552 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 553 554 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 555 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 556 557 if (unlikely(ssk_rbuf > sk_rbuf)) { 558 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); 559 sk_rbuf = ssk_rbuf; 560 } 561 } 562 563 pr_debug("msk=%p ssk=%p", msk, ssk); 564 tp = tcp_sk(ssk); 565 do { 566 u32 map_remaining, offset; 567 u32 seq = tp->copied_seq; 568 struct sk_buff *skb; 569 bool fin; 570 571 /* try to move as much data as available */ 572 map_remaining = subflow->map_data_len - 573 mptcp_subflow_get_map_offset(subflow); 574 575 skb = skb_peek(&ssk->sk_receive_queue); 576 if (!skb) { 577 /* if no data is found, a racing workqueue/recvmsg 578 * already processed the new data, stop here or we 579 * can enter an infinite loop 580 */ 581 if (!moved) 582 done = true; 583 break; 584 } 585 586 if (__mptcp_check_fallback(msk)) { 587 /* if we are running under the workqueue, TCP could have 588 * collapsed skbs between dummy map creation and now 589 * be sure to adjust the size 590 */ 591 map_remaining = skb->len; 592 subflow->map_data_len = skb->len; 593 } 594 595 offset = seq - TCP_SKB_CB(skb)->seq; 596 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; 597 if (fin) { 598 done = true; 599 seq++; 600 } 601 602 if (offset < skb->len) { 603 size_t len = skb->len - offset; 604 605 if (tp->urg_data) 606 done = true; 607 608 if (__mptcp_move_skb(msk, ssk, skb, offset, len)) 609 moved += len; 610 seq += len; 611 612 if (WARN_ON_ONCE(map_remaining < len)) 613 break; 614 } else { 615 WARN_ON_ONCE(!fin); 616 sk_eat_skb(ssk, skb); 617 done = true; 618 } 619 620 WRITE_ONCE(tp->copied_seq, seq); 621 more_data_avail = mptcp_subflow_data_available(ssk); 622 623 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { 624 done = true; 625 break; 626 } 627 } while (more_data_avail); 628 WRITE_ONCE(msk->ack_hint, ssk); 629 630 *bytes += moved; 631 return done; 632 } 633 634 static bool __mptcp_ofo_queue(struct mptcp_sock *msk) 635 { 636 struct sock *sk = (struct sock *)msk; 637 struct sk_buff *skb, *tail; 638 bool moved = false; 639 struct rb_node *p; 640 u64 end_seq; 641 642 p = rb_first(&msk->out_of_order_queue); 643 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); 644 while (p) { 645 skb = rb_to_skb(p); 646 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) 647 break; 648 649 p = rb_next(p); 650 rb_erase(&skb->rbnode, &msk->out_of_order_queue); 651 652 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, 653 msk->ack_seq))) { 654 mptcp_drop(sk, skb); 655 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 656 continue; 657 } 658 659 end_seq = MPTCP_SKB_CB(skb)->end_seq; 660 tail = skb_peek_tail(&sk->sk_receive_queue); 661 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { 662 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 663 664 /* skip overlapping data, if any */ 665 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", 666 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, 667 delta); 668 MPTCP_SKB_CB(skb)->offset += delta; 669 __skb_queue_tail(&sk->sk_receive_queue, skb); 670 } 671 msk->ack_seq = end_seq; 672 moved = true; 673 } 674 return moved; 675 } 676 677 /* In most cases we will be able to lock the mptcp socket. If its already 678 * owned, we need to defer to the work queue to avoid ABBA deadlock. 679 */ 680 static void move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 681 { 682 struct sock *sk = (struct sock *)msk; 683 unsigned int moved = 0; 684 685 if (inet_sk_state_load(sk) == TCP_CLOSE) 686 return; 687 688 mptcp_data_lock(sk); 689 690 __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 691 __mptcp_ofo_queue(msk); 692 693 /* If the moves have caught up with the DATA_FIN sequence number 694 * it's time to ack the DATA_FIN and change socket state, but 695 * this is not a good place to change state. Let the workqueue 696 * do it. 697 */ 698 if (mptcp_pending_data_fin(sk, NULL)) 699 mptcp_schedule_work(sk); 700 mptcp_data_unlock(sk); 701 } 702 703 void mptcp_data_ready(struct sock *sk, struct sock *ssk) 704 { 705 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 706 struct mptcp_sock *msk = mptcp_sk(sk); 707 int sk_rbuf, ssk_rbuf; 708 bool wake; 709 710 /* The peer can send data while we are shutting down this 711 * subflow at msk destruction time, but we must avoid enqueuing 712 * more data to the msk receive queue 713 */ 714 if (unlikely(subflow->disposable)) 715 return; 716 717 /* move_skbs_to_msk below can legitly clear the data_avail flag, 718 * but we will need later to properly woke the reader, cache its 719 * value 720 */ 721 wake = subflow->data_avail == MPTCP_SUBFLOW_DATA_AVAIL; 722 if (wake) 723 set_bit(MPTCP_DATA_READY, &msk->flags); 724 725 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 726 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 727 if (unlikely(ssk_rbuf > sk_rbuf)) 728 sk_rbuf = ssk_rbuf; 729 730 /* over limit? can't append more skbs to msk */ 731 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) 732 goto wake; 733 734 move_skbs_to_msk(msk, ssk); 735 736 wake: 737 if (wake) 738 sk->sk_data_ready(sk); 739 } 740 741 static bool mptcp_do_flush_join_list(struct mptcp_sock *msk) 742 { 743 struct mptcp_subflow_context *subflow; 744 bool ret = false; 745 746 if (likely(list_empty(&msk->join_list))) 747 return false; 748 749 spin_lock_bh(&msk->join_list_lock); 750 list_for_each_entry(subflow, &msk->join_list, node) { 751 u32 sseq = READ_ONCE(subflow->setsockopt_seq); 752 753 mptcp_propagate_sndbuf((struct sock *)msk, mptcp_subflow_tcp_sock(subflow)); 754 if (READ_ONCE(msk->setsockopt_seq) != sseq) 755 ret = true; 756 } 757 list_splice_tail_init(&msk->join_list, &msk->conn_list); 758 spin_unlock_bh(&msk->join_list_lock); 759 760 return ret; 761 } 762 763 void __mptcp_flush_join_list(struct mptcp_sock *msk) 764 { 765 if (likely(!mptcp_do_flush_join_list(msk))) 766 return; 767 768 if (!test_and_set_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags)) 769 mptcp_schedule_work((struct sock *)msk); 770 } 771 772 static void mptcp_flush_join_list(struct mptcp_sock *msk) 773 { 774 bool sync_needed = test_and_clear_bit(MPTCP_WORK_SYNC_SETSOCKOPT, &msk->flags); 775 776 might_sleep(); 777 778 if (!mptcp_do_flush_join_list(msk) && !sync_needed) 779 return; 780 781 mptcp_sockopt_sync_all(msk); 782 } 783 784 static bool mptcp_timer_pending(struct sock *sk) 785 { 786 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); 787 } 788 789 static void mptcp_reset_timer(struct sock *sk) 790 { 791 struct inet_connection_sock *icsk = inet_csk(sk); 792 unsigned long tout; 793 794 /* prevent rescheduling on close */ 795 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) 796 return; 797 798 /* should never be called with mptcp level timer cleared */ 799 tout = READ_ONCE(mptcp_sk(sk)->timer_ival); 800 if (WARN_ON_ONCE(!tout)) 801 tout = TCP_RTO_MIN; 802 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); 803 } 804 805 bool mptcp_schedule_work(struct sock *sk) 806 { 807 if (inet_sk_state_load(sk) != TCP_CLOSE && 808 schedule_work(&mptcp_sk(sk)->work)) { 809 /* each subflow already holds a reference to the sk, and the 810 * workqueue is invoked by a subflow, so sk can't go away here. 811 */ 812 sock_hold(sk); 813 return true; 814 } 815 return false; 816 } 817 818 void mptcp_subflow_eof(struct sock *sk) 819 { 820 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags)) 821 mptcp_schedule_work(sk); 822 } 823 824 static void mptcp_check_for_eof(struct mptcp_sock *msk) 825 { 826 struct mptcp_subflow_context *subflow; 827 struct sock *sk = (struct sock *)msk; 828 int receivers = 0; 829 830 mptcp_for_each_subflow(msk, subflow) 831 receivers += !subflow->rx_eof; 832 if (receivers) 833 return; 834 835 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) { 836 /* hopefully temporary hack: propagate shutdown status 837 * to msk, when all subflows agree on it 838 */ 839 sk->sk_shutdown |= RCV_SHUTDOWN; 840 841 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 842 set_bit(MPTCP_DATA_READY, &msk->flags); 843 sk->sk_data_ready(sk); 844 } 845 846 switch (sk->sk_state) { 847 case TCP_ESTABLISHED: 848 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 849 break; 850 case TCP_FIN_WAIT1: 851 inet_sk_state_store(sk, TCP_CLOSING); 852 break; 853 case TCP_FIN_WAIT2: 854 inet_sk_state_store(sk, TCP_CLOSE); 855 break; 856 default: 857 return; 858 } 859 mptcp_close_wake_up(sk); 860 } 861 862 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) 863 { 864 struct mptcp_subflow_context *subflow; 865 struct sock *sk = (struct sock *)msk; 866 867 sock_owned_by_me(sk); 868 869 mptcp_for_each_subflow(msk, subflow) { 870 if (subflow->data_avail) 871 return mptcp_subflow_tcp_sock(subflow); 872 } 873 874 return NULL; 875 } 876 877 static bool mptcp_skb_can_collapse_to(u64 write_seq, 878 const struct sk_buff *skb, 879 const struct mptcp_ext *mpext) 880 { 881 if (!tcp_skb_can_collapse_to(skb)) 882 return false; 883 884 /* can collapse only if MPTCP level sequence is in order and this 885 * mapping has not been xmitted yet 886 */ 887 return mpext && mpext->data_seq + mpext->data_len == write_seq && 888 !mpext->frozen; 889 } 890 891 /* we can append data to the given data frag if: 892 * - there is space available in the backing page_frag 893 * - the data frag tail matches the current page_frag free offset 894 * - the data frag end sequence number matches the current write seq 895 */ 896 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 897 const struct page_frag *pfrag, 898 const struct mptcp_data_frag *df) 899 { 900 return df && pfrag->page == df->page && 901 pfrag->size - pfrag->offset > 0 && 902 pfrag->offset == (df->offset + df->data_len) && 903 df->data_seq + df->data_len == msk->write_seq; 904 } 905 906 static int mptcp_wmem_with_overhead(struct sock *sk, int size) 907 { 908 struct mptcp_sock *msk = mptcp_sk(sk); 909 int ret, skbs; 910 911 ret = size + ((sizeof(struct mptcp_data_frag) * size) >> PAGE_SHIFT); 912 skbs = (msk->tx_pending_data + size) / msk->size_goal_cache; 913 if (skbs < msk->skb_tx_cache.qlen) 914 return ret; 915 916 return ret + (skbs - msk->skb_tx_cache.qlen) * SKB_TRUESIZE(MAX_TCP_HEADER); 917 } 918 919 static void __mptcp_wmem_reserve(struct sock *sk, int size) 920 { 921 int amount = mptcp_wmem_with_overhead(sk, size); 922 struct mptcp_sock *msk = mptcp_sk(sk); 923 924 WARN_ON_ONCE(msk->wmem_reserved); 925 if (WARN_ON_ONCE(amount < 0)) 926 amount = 0; 927 928 if (amount <= sk->sk_forward_alloc) 929 goto reserve; 930 931 /* under memory pressure try to reserve at most a single page 932 * otherwise try to reserve the full estimate and fallback 933 * to a single page before entering the error path 934 */ 935 if ((tcp_under_memory_pressure(sk) && amount > PAGE_SIZE) || 936 !sk_wmem_schedule(sk, amount)) { 937 if (amount <= PAGE_SIZE) 938 goto nomem; 939 940 amount = PAGE_SIZE; 941 if (!sk_wmem_schedule(sk, amount)) 942 goto nomem; 943 } 944 945 reserve: 946 msk->wmem_reserved = amount; 947 sk->sk_forward_alloc -= amount; 948 return; 949 950 nomem: 951 /* we will wait for memory on next allocation */ 952 msk->wmem_reserved = -1; 953 } 954 955 static void __mptcp_update_wmem(struct sock *sk) 956 { 957 struct mptcp_sock *msk = mptcp_sk(sk); 958 959 #ifdef CONFIG_LOCKDEP 960 WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock)); 961 #endif 962 963 if (!msk->wmem_reserved) 964 return; 965 966 if (msk->wmem_reserved < 0) 967 msk->wmem_reserved = 0; 968 if (msk->wmem_reserved > 0) { 969 sk->sk_forward_alloc += msk->wmem_reserved; 970 msk->wmem_reserved = 0; 971 } 972 } 973 974 static bool mptcp_wmem_alloc(struct sock *sk, int size) 975 { 976 struct mptcp_sock *msk = mptcp_sk(sk); 977 978 /* check for pre-existing error condition */ 979 if (msk->wmem_reserved < 0) 980 return false; 981 982 if (msk->wmem_reserved >= size) 983 goto account; 984 985 mptcp_data_lock(sk); 986 if (!sk_wmem_schedule(sk, size)) { 987 mptcp_data_unlock(sk); 988 return false; 989 } 990 991 sk->sk_forward_alloc -= size; 992 msk->wmem_reserved += size; 993 mptcp_data_unlock(sk); 994 995 account: 996 msk->wmem_reserved -= size; 997 return true; 998 } 999 1000 static void mptcp_wmem_uncharge(struct sock *sk, int size) 1001 { 1002 struct mptcp_sock *msk = mptcp_sk(sk); 1003 1004 if (msk->wmem_reserved < 0) 1005 msk->wmem_reserved = 0; 1006 msk->wmem_reserved += size; 1007 } 1008 1009 static void mptcp_mem_reclaim_partial(struct sock *sk) 1010 { 1011 struct mptcp_sock *msk = mptcp_sk(sk); 1012 1013 /* if we are experiencing a transint allocation error, 1014 * the forward allocation memory has been already 1015 * released 1016 */ 1017 if (msk->wmem_reserved < 0) 1018 return; 1019 1020 mptcp_data_lock(sk); 1021 sk->sk_forward_alloc += msk->wmem_reserved; 1022 sk_mem_reclaim_partial(sk); 1023 msk->wmem_reserved = sk->sk_forward_alloc; 1024 sk->sk_forward_alloc = 0; 1025 mptcp_data_unlock(sk); 1026 } 1027 1028 static void dfrag_uncharge(struct sock *sk, int len) 1029 { 1030 sk_mem_uncharge(sk, len); 1031 sk_wmem_queued_add(sk, -len); 1032 } 1033 1034 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 1035 { 1036 int len = dfrag->data_len + dfrag->overhead; 1037 1038 list_del(&dfrag->list); 1039 dfrag_uncharge(sk, len); 1040 put_page(dfrag->page); 1041 } 1042 1043 static void __mptcp_clean_una(struct sock *sk) 1044 { 1045 struct mptcp_sock *msk = mptcp_sk(sk); 1046 struct mptcp_data_frag *dtmp, *dfrag; 1047 bool cleaned = false; 1048 u64 snd_una; 1049 1050 /* on fallback we just need to ignore snd_una, as this is really 1051 * plain TCP 1052 */ 1053 if (__mptcp_check_fallback(msk)) 1054 msk->snd_una = READ_ONCE(msk->snd_nxt); 1055 1056 snd_una = msk->snd_una; 1057 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 1058 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 1059 break; 1060 1061 if (WARN_ON_ONCE(dfrag == msk->first_pending)) 1062 break; 1063 dfrag_clear(sk, dfrag); 1064 cleaned = true; 1065 } 1066 1067 dfrag = mptcp_rtx_head(sk); 1068 if (dfrag && after64(snd_una, dfrag->data_seq)) { 1069 u64 delta = snd_una - dfrag->data_seq; 1070 1071 if (WARN_ON_ONCE(delta > dfrag->already_sent)) 1072 goto out; 1073 1074 dfrag->data_seq += delta; 1075 dfrag->offset += delta; 1076 dfrag->data_len -= delta; 1077 dfrag->already_sent -= delta; 1078 1079 dfrag_uncharge(sk, delta); 1080 cleaned = true; 1081 } 1082 1083 out: 1084 if (cleaned) { 1085 if (tcp_under_memory_pressure(sk)) { 1086 __mptcp_update_wmem(sk); 1087 sk_mem_reclaim_partial(sk); 1088 } 1089 } 1090 1091 if (snd_una == READ_ONCE(msk->snd_nxt)) { 1092 if (msk->timer_ival && !mptcp_data_fin_enabled(msk)) 1093 mptcp_stop_timer(sk); 1094 } else { 1095 mptcp_reset_timer(sk); 1096 } 1097 } 1098 1099 static void __mptcp_clean_una_wakeup(struct sock *sk) 1100 { 1101 #ifdef CONFIG_LOCKDEP 1102 WARN_ON_ONCE(!lockdep_is_held(&sk->sk_lock.slock)); 1103 #endif 1104 __mptcp_clean_una(sk); 1105 mptcp_write_space(sk); 1106 } 1107 1108 static void mptcp_clean_una_wakeup(struct sock *sk) 1109 { 1110 mptcp_data_lock(sk); 1111 __mptcp_clean_una_wakeup(sk); 1112 mptcp_data_unlock(sk); 1113 } 1114 1115 static void mptcp_enter_memory_pressure(struct sock *sk) 1116 { 1117 struct mptcp_subflow_context *subflow; 1118 struct mptcp_sock *msk = mptcp_sk(sk); 1119 bool first = true; 1120 1121 sk_stream_moderate_sndbuf(sk); 1122 mptcp_for_each_subflow(msk, subflow) { 1123 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1124 1125 if (first) 1126 tcp_enter_memory_pressure(ssk); 1127 sk_stream_moderate_sndbuf(ssk); 1128 first = false; 1129 } 1130 } 1131 1132 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 1133 * data 1134 */ 1135 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 1136 { 1137 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 1138 pfrag, sk->sk_allocation))) 1139 return true; 1140 1141 mptcp_enter_memory_pressure(sk); 1142 return false; 1143 } 1144 1145 static struct mptcp_data_frag * 1146 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 1147 int orig_offset) 1148 { 1149 int offset = ALIGN(orig_offset, sizeof(long)); 1150 struct mptcp_data_frag *dfrag; 1151 1152 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 1153 dfrag->data_len = 0; 1154 dfrag->data_seq = msk->write_seq; 1155 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 1156 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 1157 dfrag->already_sent = 0; 1158 dfrag->page = pfrag->page; 1159 1160 return dfrag; 1161 } 1162 1163 struct mptcp_sendmsg_info { 1164 int mss_now; 1165 int size_goal; 1166 u16 limit; 1167 u16 sent; 1168 unsigned int flags; 1169 }; 1170 1171 static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq, 1172 int avail_size) 1173 { 1174 u64 window_end = mptcp_wnd_end(msk); 1175 1176 if (__mptcp_check_fallback(msk)) 1177 return avail_size; 1178 1179 if (!before64(data_seq + avail_size, window_end)) { 1180 u64 allowed_size = window_end - data_seq; 1181 1182 return min_t(unsigned int, allowed_size, avail_size); 1183 } 1184 1185 return avail_size; 1186 } 1187 1188 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) 1189 { 1190 struct skb_ext *mpext = __skb_ext_alloc(gfp); 1191 1192 if (!mpext) 1193 return false; 1194 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); 1195 return true; 1196 } 1197 1198 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) 1199 { 1200 struct sk_buff *skb; 1201 1202 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); 1203 if (likely(skb)) { 1204 if (likely(__mptcp_add_ext(skb, gfp))) { 1205 skb_reserve(skb, MAX_TCP_HEADER); 1206 skb->reserved_tailroom = skb->end - skb->tail; 1207 return skb; 1208 } 1209 __kfree_skb(skb); 1210 } else { 1211 mptcp_enter_memory_pressure(sk); 1212 } 1213 return NULL; 1214 } 1215 1216 static bool mptcp_tx_cache_refill(struct sock *sk, int size, 1217 struct sk_buff_head *skbs, int *total_ts) 1218 { 1219 struct mptcp_sock *msk = mptcp_sk(sk); 1220 struct sk_buff *skb; 1221 int space_needed; 1222 1223 if (unlikely(tcp_under_memory_pressure(sk))) { 1224 mptcp_mem_reclaim_partial(sk); 1225 1226 /* under pressure pre-allocate at most a single skb */ 1227 if (msk->skb_tx_cache.qlen) 1228 return true; 1229 space_needed = msk->size_goal_cache; 1230 } else { 1231 space_needed = msk->tx_pending_data + size - 1232 msk->skb_tx_cache.qlen * msk->size_goal_cache; 1233 } 1234 1235 while (space_needed > 0) { 1236 skb = __mptcp_do_alloc_tx_skb(sk, sk->sk_allocation); 1237 if (unlikely(!skb)) { 1238 /* under memory pressure, try to pass the caller a 1239 * single skb to allow forward progress 1240 */ 1241 while (skbs->qlen > 1) { 1242 skb = __skb_dequeue_tail(skbs); 1243 *total_ts -= skb->truesize; 1244 __kfree_skb(skb); 1245 } 1246 return skbs->qlen > 0; 1247 } 1248 1249 *total_ts += skb->truesize; 1250 __skb_queue_tail(skbs, skb); 1251 space_needed -= msk->size_goal_cache; 1252 } 1253 return true; 1254 } 1255 1256 static bool __mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) 1257 { 1258 struct mptcp_sock *msk = mptcp_sk(sk); 1259 struct sk_buff *skb; 1260 1261 if (ssk->sk_tx_skb_cache) { 1262 skb = ssk->sk_tx_skb_cache; 1263 if (unlikely(!skb_ext_find(skb, SKB_EXT_MPTCP) && 1264 !__mptcp_add_ext(skb, gfp))) 1265 return false; 1266 return true; 1267 } 1268 1269 skb = skb_peek(&msk->skb_tx_cache); 1270 if (skb) { 1271 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1272 skb = __skb_dequeue(&msk->skb_tx_cache); 1273 if (WARN_ON_ONCE(!skb)) 1274 return false; 1275 1276 mptcp_wmem_uncharge(sk, skb->truesize); 1277 ssk->sk_tx_skb_cache = skb; 1278 return true; 1279 } 1280 1281 /* over memory limit, no point to try to allocate a new skb */ 1282 return false; 1283 } 1284 1285 skb = __mptcp_do_alloc_tx_skb(sk, gfp); 1286 if (!skb) 1287 return false; 1288 1289 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1290 ssk->sk_tx_skb_cache = skb; 1291 return true; 1292 } 1293 kfree_skb(skb); 1294 return false; 1295 } 1296 1297 static bool mptcp_must_reclaim_memory(struct sock *sk, struct sock *ssk) 1298 { 1299 return !ssk->sk_tx_skb_cache && 1300 !skb_peek(&mptcp_sk(sk)->skb_tx_cache) && 1301 tcp_under_memory_pressure(sk); 1302 } 1303 1304 static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk) 1305 { 1306 if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) 1307 mptcp_mem_reclaim_partial(sk); 1308 return __mptcp_alloc_tx_skb(sk, ssk, sk->sk_allocation); 1309 } 1310 1311 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 1312 struct mptcp_data_frag *dfrag, 1313 struct mptcp_sendmsg_info *info) 1314 { 1315 u64 data_seq = dfrag->data_seq + info->sent; 1316 struct mptcp_sock *msk = mptcp_sk(sk); 1317 bool zero_window_probe = false; 1318 struct mptcp_ext *mpext = NULL; 1319 struct sk_buff *skb, *tail; 1320 bool can_collapse = false; 1321 int size_bias = 0; 1322 int avail_size; 1323 size_t ret = 0; 1324 1325 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", 1326 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); 1327 1328 /* compute send limit */ 1329 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); 1330 avail_size = info->size_goal; 1331 msk->size_goal_cache = info->size_goal; 1332 skb = tcp_write_queue_tail(ssk); 1333 if (skb) { 1334 /* Limit the write to the size available in the 1335 * current skb, if any, so that we create at most a new skb. 1336 * Explicitly tells TCP internals to avoid collapsing on later 1337 * queue management operation, to avoid breaking the ext <-> 1338 * SSN association set here 1339 */ 1340 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1341 can_collapse = (info->size_goal - skb->len > 0) && 1342 mptcp_skb_can_collapse_to(data_seq, skb, mpext); 1343 if (!can_collapse) { 1344 TCP_SKB_CB(skb)->eor = 1; 1345 } else { 1346 size_bias = skb->len; 1347 avail_size = info->size_goal - skb->len; 1348 } 1349 } 1350 1351 /* Zero window and all data acked? Probe. */ 1352 avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size); 1353 if (avail_size == 0) { 1354 u64 snd_una = READ_ONCE(msk->snd_una); 1355 1356 if (skb || snd_una != msk->snd_nxt) 1357 return 0; 1358 zero_window_probe = true; 1359 data_seq = snd_una - 1; 1360 avail_size = 1; 1361 } 1362 1363 if (WARN_ON_ONCE(info->sent > info->limit || 1364 info->limit > dfrag->data_len)) 1365 return 0; 1366 1367 ret = info->limit - info->sent; 1368 tail = tcp_build_frag(ssk, avail_size + size_bias, info->flags, 1369 dfrag->page, dfrag->offset + info->sent, &ret); 1370 if (!tail) { 1371 tcp_remove_empty_skb(sk, tcp_write_queue_tail(ssk)); 1372 return -ENOMEM; 1373 } 1374 1375 /* if the tail skb is still the cached one, collapsing really happened. 1376 */ 1377 if (skb == tail) { 1378 TCP_SKB_CB(tail)->tcp_flags &= ~TCPHDR_PSH; 1379 mpext->data_len += ret; 1380 WARN_ON_ONCE(!can_collapse); 1381 WARN_ON_ONCE(zero_window_probe); 1382 goto out; 1383 } 1384 1385 mpext = skb_ext_find(tail, SKB_EXT_MPTCP); 1386 if (WARN_ON_ONCE(!mpext)) { 1387 /* should never reach here, stream corrupted */ 1388 return -EINVAL; 1389 } 1390 1391 memset(mpext, 0, sizeof(*mpext)); 1392 mpext->data_seq = data_seq; 1393 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 1394 mpext->data_len = ret; 1395 mpext->use_map = 1; 1396 mpext->dsn64 = 1; 1397 1398 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 1399 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 1400 mpext->dsn64); 1401 1402 if (zero_window_probe) { 1403 mptcp_subflow_ctx(ssk)->rel_write_seq += ret; 1404 mpext->frozen = 1; 1405 ret = 0; 1406 tcp_push_pending_frames(ssk); 1407 } 1408 out: 1409 mptcp_subflow_ctx(ssk)->rel_write_seq += ret; 1410 return ret; 1411 } 1412 1413 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ 1414 sizeof(struct tcphdr) - \ 1415 MAX_TCP_OPTION_SPACE - \ 1416 sizeof(struct ipv6hdr) - \ 1417 sizeof(struct frag_hdr)) 1418 1419 struct subflow_send_info { 1420 struct sock *ssk; 1421 u64 ratio; 1422 }; 1423 1424 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 1425 { 1426 struct subflow_send_info send_info[2]; 1427 struct mptcp_subflow_context *subflow; 1428 int i, nr_active = 0; 1429 struct sock *ssk; 1430 u64 ratio; 1431 u32 pace; 1432 1433 sock_owned_by_me((struct sock *)msk); 1434 1435 if (__mptcp_check_fallback(msk)) { 1436 if (!msk->first) 1437 return NULL; 1438 return sk_stream_memory_free(msk->first) ? msk->first : NULL; 1439 } 1440 1441 /* re-use last subflow, if the burst allow that */ 1442 if (msk->last_snd && msk->snd_burst > 0 && 1443 sk_stream_memory_free(msk->last_snd) && 1444 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) 1445 return msk->last_snd; 1446 1447 /* pick the subflow with the lower wmem/wspace ratio */ 1448 for (i = 0; i < 2; ++i) { 1449 send_info[i].ssk = NULL; 1450 send_info[i].ratio = -1; 1451 } 1452 mptcp_for_each_subflow(msk, subflow) { 1453 trace_mptcp_subflow_get_send(subflow); 1454 ssk = mptcp_subflow_tcp_sock(subflow); 1455 if (!mptcp_subflow_active(subflow)) 1456 continue; 1457 1458 nr_active += !subflow->backup; 1459 if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd) 1460 continue; 1461 1462 pace = READ_ONCE(ssk->sk_pacing_rate); 1463 if (!pace) 1464 continue; 1465 1466 ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, 1467 pace); 1468 if (ratio < send_info[subflow->backup].ratio) { 1469 send_info[subflow->backup].ssk = ssk; 1470 send_info[subflow->backup].ratio = ratio; 1471 } 1472 } 1473 1474 /* pick the best backup if no other subflow is active */ 1475 if (!nr_active) 1476 send_info[0].ssk = send_info[1].ssk; 1477 1478 if (send_info[0].ssk) { 1479 msk->last_snd = send_info[0].ssk; 1480 msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE, 1481 tcp_sk(msk->last_snd)->snd_wnd); 1482 return msk->last_snd; 1483 } 1484 1485 return NULL; 1486 } 1487 1488 static void mptcp_push_release(struct sock *sk, struct sock *ssk, 1489 struct mptcp_sendmsg_info *info) 1490 { 1491 mptcp_set_timeout(sk, ssk); 1492 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); 1493 release_sock(ssk); 1494 } 1495 1496 static void __mptcp_push_pending(struct sock *sk, unsigned int flags) 1497 { 1498 struct sock *prev_ssk = NULL, *ssk = NULL; 1499 struct mptcp_sock *msk = mptcp_sk(sk); 1500 struct mptcp_sendmsg_info info = { 1501 .flags = flags, 1502 }; 1503 struct mptcp_data_frag *dfrag; 1504 int len, copied = 0; 1505 1506 while ((dfrag = mptcp_send_head(sk))) { 1507 info.sent = dfrag->already_sent; 1508 info.limit = dfrag->data_len; 1509 len = dfrag->data_len - dfrag->already_sent; 1510 while (len > 0) { 1511 int ret = 0; 1512 1513 prev_ssk = ssk; 1514 mptcp_flush_join_list(msk); 1515 ssk = mptcp_subflow_get_send(msk); 1516 1517 /* try to keep the subflow socket lock across 1518 * consecutive xmit on the same socket 1519 */ 1520 if (ssk != prev_ssk && prev_ssk) 1521 mptcp_push_release(sk, prev_ssk, &info); 1522 if (!ssk) 1523 goto out; 1524 1525 if (ssk != prev_ssk || !prev_ssk) 1526 lock_sock(ssk); 1527 1528 /* keep it simple and always provide a new skb for the 1529 * subflow, even if we will not use it when collapsing 1530 * on the pending one 1531 */ 1532 if (!mptcp_alloc_tx_skb(sk, ssk)) { 1533 mptcp_push_release(sk, ssk, &info); 1534 goto out; 1535 } 1536 1537 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1538 if (ret <= 0) { 1539 mptcp_push_release(sk, ssk, &info); 1540 goto out; 1541 } 1542 1543 info.sent += ret; 1544 dfrag->already_sent += ret; 1545 msk->snd_nxt += ret; 1546 msk->snd_burst -= ret; 1547 msk->tx_pending_data -= ret; 1548 copied += ret; 1549 len -= ret; 1550 } 1551 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1552 } 1553 1554 /* at this point we held the socket lock for the last subflow we used */ 1555 if (ssk) 1556 mptcp_push_release(sk, ssk, &info); 1557 1558 out: 1559 if (copied) { 1560 /* start the timer, if it's not pending */ 1561 if (!mptcp_timer_pending(sk)) 1562 mptcp_reset_timer(sk); 1563 __mptcp_check_send_data_fin(sk); 1564 } 1565 } 1566 1567 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) 1568 { 1569 struct mptcp_sock *msk = mptcp_sk(sk); 1570 struct mptcp_sendmsg_info info; 1571 struct mptcp_data_frag *dfrag; 1572 struct sock *xmit_ssk; 1573 int len, copied = 0; 1574 bool first = true; 1575 1576 info.flags = 0; 1577 while ((dfrag = mptcp_send_head(sk))) { 1578 info.sent = dfrag->already_sent; 1579 info.limit = dfrag->data_len; 1580 len = dfrag->data_len - dfrag->already_sent; 1581 while (len > 0) { 1582 int ret = 0; 1583 1584 /* the caller already invoked the packet scheduler, 1585 * check for a different subflow usage only after 1586 * spooling the first chunk of data 1587 */ 1588 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk)); 1589 if (!xmit_ssk) 1590 goto out; 1591 if (xmit_ssk != ssk) { 1592 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk)); 1593 goto out; 1594 } 1595 1596 if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) { 1597 __mptcp_update_wmem(sk); 1598 sk_mem_reclaim_partial(sk); 1599 } 1600 if (!__mptcp_alloc_tx_skb(sk, ssk, GFP_ATOMIC)) 1601 goto out; 1602 1603 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1604 if (ret <= 0) 1605 goto out; 1606 1607 info.sent += ret; 1608 dfrag->already_sent += ret; 1609 msk->snd_nxt += ret; 1610 msk->snd_burst -= ret; 1611 msk->tx_pending_data -= ret; 1612 copied += ret; 1613 len -= ret; 1614 first = false; 1615 } 1616 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1617 } 1618 1619 out: 1620 /* __mptcp_alloc_tx_skb could have released some wmem and we are 1621 * not going to flush it via release_sock() 1622 */ 1623 __mptcp_update_wmem(sk); 1624 if (copied) { 1625 mptcp_set_timeout(sk, ssk); 1626 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 1627 info.size_goal); 1628 if (!mptcp_timer_pending(sk)) 1629 mptcp_reset_timer(sk); 1630 1631 if (msk->snd_data_fin_enable && 1632 msk->snd_nxt + 1 == msk->write_seq) 1633 mptcp_schedule_work(sk); 1634 } 1635 } 1636 1637 static void mptcp_set_nospace(struct sock *sk) 1638 { 1639 /* enable autotune */ 1640 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1641 1642 /* will be cleared on avail space */ 1643 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); 1644 } 1645 1646 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1647 { 1648 struct mptcp_sock *msk = mptcp_sk(sk); 1649 struct page_frag *pfrag; 1650 size_t copied = 0; 1651 int ret = 0; 1652 long timeo; 1653 1654 /* we don't support FASTOPEN yet */ 1655 if (msg->msg_flags & MSG_FASTOPEN) 1656 return -EOPNOTSUPP; 1657 1658 /* silently ignore everything else */ 1659 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL; 1660 1661 mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, min_t(size_t, 1 << 20, len))); 1662 1663 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1664 1665 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 1666 ret = sk_stream_wait_connect(sk, &timeo); 1667 if (ret) 1668 goto out; 1669 } 1670 1671 pfrag = sk_page_frag(sk); 1672 1673 while (msg_data_left(msg)) { 1674 int total_ts, frag_truesize = 0; 1675 struct mptcp_data_frag *dfrag; 1676 struct sk_buff_head skbs; 1677 bool dfrag_collapsed; 1678 size_t psize, offset; 1679 1680 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { 1681 ret = -EPIPE; 1682 goto out; 1683 } 1684 1685 /* reuse tail pfrag, if possible, or carve a new one from the 1686 * page allocator 1687 */ 1688 dfrag = mptcp_pending_tail(sk); 1689 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 1690 if (!dfrag_collapsed) { 1691 if (!sk_stream_memory_free(sk)) 1692 goto wait_for_memory; 1693 1694 if (!mptcp_page_frag_refill(sk, pfrag)) 1695 goto wait_for_memory; 1696 1697 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); 1698 frag_truesize = dfrag->overhead; 1699 } 1700 1701 /* we do not bound vs wspace, to allow a single packet. 1702 * memory accounting will prevent execessive memory usage 1703 * anyway 1704 */ 1705 offset = dfrag->offset + dfrag->data_len; 1706 psize = pfrag->size - offset; 1707 psize = min_t(size_t, psize, msg_data_left(msg)); 1708 total_ts = psize + frag_truesize; 1709 __skb_queue_head_init(&skbs); 1710 if (!mptcp_tx_cache_refill(sk, psize, &skbs, &total_ts)) 1711 goto wait_for_memory; 1712 1713 if (!mptcp_wmem_alloc(sk, total_ts)) { 1714 __skb_queue_purge(&skbs); 1715 goto wait_for_memory; 1716 } 1717 1718 skb_queue_splice_tail(&skbs, &msk->skb_tx_cache); 1719 if (copy_page_from_iter(dfrag->page, offset, psize, 1720 &msg->msg_iter) != psize) { 1721 mptcp_wmem_uncharge(sk, psize + frag_truesize); 1722 ret = -EFAULT; 1723 goto out; 1724 } 1725 1726 /* data successfully copied into the write queue */ 1727 copied += psize; 1728 dfrag->data_len += psize; 1729 frag_truesize += psize; 1730 pfrag->offset += frag_truesize; 1731 WRITE_ONCE(msk->write_seq, msk->write_seq + psize); 1732 msk->tx_pending_data += psize; 1733 1734 /* charge data on mptcp pending queue to the msk socket 1735 * Note: we charge such data both to sk and ssk 1736 */ 1737 sk_wmem_queued_add(sk, frag_truesize); 1738 if (!dfrag_collapsed) { 1739 get_page(dfrag->page); 1740 list_add_tail(&dfrag->list, &msk->rtx_queue); 1741 if (!msk->first_pending) 1742 WRITE_ONCE(msk->first_pending, dfrag); 1743 } 1744 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, 1745 dfrag->data_seq, dfrag->data_len, dfrag->already_sent, 1746 !dfrag_collapsed); 1747 1748 continue; 1749 1750 wait_for_memory: 1751 mptcp_set_nospace(sk); 1752 __mptcp_push_pending(sk, msg->msg_flags); 1753 ret = sk_stream_wait_memory(sk, &timeo); 1754 if (ret) 1755 goto out; 1756 } 1757 1758 if (copied) 1759 __mptcp_push_pending(sk, msg->msg_flags); 1760 1761 out: 1762 release_sock(sk); 1763 return copied ? : ret; 1764 } 1765 1766 static void mptcp_wait_data(struct sock *sk, long *timeo) 1767 { 1768 DEFINE_WAIT_FUNC(wait, woken_wake_function); 1769 struct mptcp_sock *msk = mptcp_sk(sk); 1770 1771 add_wait_queue(sk_sleep(sk), &wait); 1772 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1773 1774 sk_wait_event(sk, timeo, 1775 test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait); 1776 1777 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1778 remove_wait_queue(sk_sleep(sk), &wait); 1779 } 1780 1781 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1782 struct msghdr *msg, 1783 size_t len, int flags, 1784 struct scm_timestamping_internal *tss, 1785 int *cmsg_flags) 1786 { 1787 struct sk_buff *skb, *tmp; 1788 int copied = 0; 1789 1790 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { 1791 u32 offset = MPTCP_SKB_CB(skb)->offset; 1792 u32 data_len = skb->len - offset; 1793 u32 count = min_t(size_t, len - copied, data_len); 1794 int err; 1795 1796 if (!(flags & MSG_TRUNC)) { 1797 err = skb_copy_datagram_msg(skb, offset, msg, count); 1798 if (unlikely(err < 0)) { 1799 if (!copied) 1800 return err; 1801 break; 1802 } 1803 } 1804 1805 if (MPTCP_SKB_CB(skb)->has_rxtstamp) { 1806 tcp_update_recv_tstamps(skb, tss); 1807 *cmsg_flags |= MPTCP_CMSG_TS; 1808 } 1809 1810 copied += count; 1811 1812 if (count < data_len) { 1813 if (!(flags & MSG_PEEK)) 1814 MPTCP_SKB_CB(skb)->offset += count; 1815 break; 1816 } 1817 1818 if (!(flags & MSG_PEEK)) { 1819 /* we will bulk release the skb memory later */ 1820 skb->destructor = NULL; 1821 msk->rmem_released += skb->truesize; 1822 __skb_unlink(skb, &msk->receive_queue); 1823 __kfree_skb(skb); 1824 } 1825 1826 if (copied >= len) 1827 break; 1828 } 1829 1830 return copied; 1831 } 1832 1833 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1834 * 1835 * Only difference: Use highest rtt estimate of the subflows in use. 1836 */ 1837 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1838 { 1839 struct mptcp_subflow_context *subflow; 1840 struct sock *sk = (struct sock *)msk; 1841 u32 time, advmss = 1; 1842 u64 rtt_us, mstamp; 1843 1844 sock_owned_by_me(sk); 1845 1846 if (copied <= 0) 1847 return; 1848 1849 msk->rcvq_space.copied += copied; 1850 1851 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1852 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1853 1854 rtt_us = msk->rcvq_space.rtt_us; 1855 if (rtt_us && time < (rtt_us >> 3)) 1856 return; 1857 1858 rtt_us = 0; 1859 mptcp_for_each_subflow(msk, subflow) { 1860 const struct tcp_sock *tp; 1861 u64 sf_rtt_us; 1862 u32 sf_advmss; 1863 1864 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1865 1866 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1867 sf_advmss = READ_ONCE(tp->advmss); 1868 1869 rtt_us = max(sf_rtt_us, rtt_us); 1870 advmss = max(sf_advmss, advmss); 1871 } 1872 1873 msk->rcvq_space.rtt_us = rtt_us; 1874 if (time < (rtt_us >> 3) || rtt_us == 0) 1875 return; 1876 1877 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 1878 goto new_measure; 1879 1880 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && 1881 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 1882 int rcvmem, rcvbuf; 1883 u64 rcvwin, grow; 1884 1885 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 1886 1887 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 1888 1889 do_div(grow, msk->rcvq_space.space); 1890 rcvwin += (grow << 1); 1891 1892 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER); 1893 while (tcp_win_from_space(sk, rcvmem) < advmss) 1894 rcvmem += 128; 1895 1896 do_div(rcvwin, advmss); 1897 rcvbuf = min_t(u64, rcvwin * rcvmem, 1898 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); 1899 1900 if (rcvbuf > sk->sk_rcvbuf) { 1901 u32 window_clamp; 1902 1903 window_clamp = tcp_win_from_space(sk, rcvbuf); 1904 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 1905 1906 /* Make subflows follow along. If we do not do this, we 1907 * get drops at subflow level if skbs can't be moved to 1908 * the mptcp rx queue fast enough (announced rcv_win can 1909 * exceed ssk->sk_rcvbuf). 1910 */ 1911 mptcp_for_each_subflow(msk, subflow) { 1912 struct sock *ssk; 1913 bool slow; 1914 1915 ssk = mptcp_subflow_tcp_sock(subflow); 1916 slow = lock_sock_fast(ssk); 1917 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 1918 tcp_sk(ssk)->window_clamp = window_clamp; 1919 tcp_cleanup_rbuf(ssk, 1); 1920 unlock_sock_fast(ssk, slow); 1921 } 1922 } 1923 } 1924 1925 msk->rcvq_space.space = msk->rcvq_space.copied; 1926 new_measure: 1927 msk->rcvq_space.copied = 0; 1928 msk->rcvq_space.time = mstamp; 1929 } 1930 1931 static void __mptcp_update_rmem(struct sock *sk) 1932 { 1933 struct mptcp_sock *msk = mptcp_sk(sk); 1934 1935 if (!msk->rmem_released) 1936 return; 1937 1938 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); 1939 sk_mem_uncharge(sk, msk->rmem_released); 1940 msk->rmem_released = 0; 1941 } 1942 1943 static void __mptcp_splice_receive_queue(struct sock *sk) 1944 { 1945 struct mptcp_sock *msk = mptcp_sk(sk); 1946 1947 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); 1948 } 1949 1950 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 1951 { 1952 struct sock *sk = (struct sock *)msk; 1953 unsigned int moved = 0; 1954 bool ret, done; 1955 1956 mptcp_flush_join_list(msk); 1957 do { 1958 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 1959 bool slowpath; 1960 1961 /* we can have data pending in the subflows only if the msk 1962 * receive buffer was full at subflow_data_ready() time, 1963 * that is an unlikely slow path. 1964 */ 1965 if (likely(!ssk)) 1966 break; 1967 1968 slowpath = lock_sock_fast(ssk); 1969 mptcp_data_lock(sk); 1970 __mptcp_update_rmem(sk); 1971 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 1972 mptcp_data_unlock(sk); 1973 tcp_cleanup_rbuf(ssk, moved); 1974 unlock_sock_fast(ssk, slowpath); 1975 } while (!done); 1976 1977 /* acquire the data lock only if some input data is pending */ 1978 ret = moved > 0; 1979 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || 1980 !skb_queue_empty_lockless(&sk->sk_receive_queue)) { 1981 mptcp_data_lock(sk); 1982 __mptcp_update_rmem(sk); 1983 ret |= __mptcp_ofo_queue(msk); 1984 __mptcp_splice_receive_queue(sk); 1985 mptcp_data_unlock(sk); 1986 mptcp_cleanup_rbuf(msk); 1987 } 1988 if (ret) 1989 mptcp_check_data_fin((struct sock *)msk); 1990 return !skb_queue_empty(&msk->receive_queue); 1991 } 1992 1993 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 1994 int nonblock, int flags, int *addr_len) 1995 { 1996 struct mptcp_sock *msk = mptcp_sk(sk); 1997 struct scm_timestamping_internal tss; 1998 int copied = 0, cmsg_flags = 0; 1999 int target; 2000 long timeo; 2001 2002 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ 2003 if (unlikely(flags & MSG_ERRQUEUE)) 2004 return inet_recv_error(sk, msg, len, addr_len); 2005 2006 mptcp_lock_sock(sk, __mptcp_splice_receive_queue(sk)); 2007 if (unlikely(sk->sk_state == TCP_LISTEN)) { 2008 copied = -ENOTCONN; 2009 goto out_err; 2010 } 2011 2012 timeo = sock_rcvtimeo(sk, nonblock); 2013 2014 len = min_t(size_t, len, INT_MAX); 2015 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 2016 2017 while (copied < len) { 2018 int bytes_read; 2019 2020 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); 2021 if (unlikely(bytes_read < 0)) { 2022 if (!copied) 2023 copied = bytes_read; 2024 goto out_err; 2025 } 2026 2027 copied += bytes_read; 2028 2029 /* be sure to advertise window change */ 2030 mptcp_cleanup_rbuf(msk); 2031 2032 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) 2033 continue; 2034 2035 /* only the master socket status is relevant here. The exit 2036 * conditions mirror closely tcp_recvmsg() 2037 */ 2038 if (copied >= target) 2039 break; 2040 2041 if (copied) { 2042 if (sk->sk_err || 2043 sk->sk_state == TCP_CLOSE || 2044 (sk->sk_shutdown & RCV_SHUTDOWN) || 2045 !timeo || 2046 signal_pending(current)) 2047 break; 2048 } else { 2049 if (sk->sk_err) { 2050 copied = sock_error(sk); 2051 break; 2052 } 2053 2054 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2055 mptcp_check_for_eof(msk); 2056 2057 if (sk->sk_shutdown & RCV_SHUTDOWN) { 2058 /* race breaker: the shutdown could be after the 2059 * previous receive queue check 2060 */ 2061 if (__mptcp_move_skbs(msk)) 2062 continue; 2063 break; 2064 } 2065 2066 if (sk->sk_state == TCP_CLOSE) { 2067 copied = -ENOTCONN; 2068 break; 2069 } 2070 2071 if (!timeo) { 2072 copied = -EAGAIN; 2073 break; 2074 } 2075 2076 if (signal_pending(current)) { 2077 copied = sock_intr_errno(timeo); 2078 break; 2079 } 2080 } 2081 2082 pr_debug("block timeout %ld", timeo); 2083 mptcp_wait_data(sk, &timeo); 2084 } 2085 2086 if (skb_queue_empty_lockless(&sk->sk_receive_queue) && 2087 skb_queue_empty(&msk->receive_queue)) { 2088 /* entire backlog drained, clear DATA_READY. */ 2089 clear_bit(MPTCP_DATA_READY, &msk->flags); 2090 2091 /* .. race-breaker: ssk might have gotten new data 2092 * after last __mptcp_move_skbs() returned false. 2093 */ 2094 if (unlikely(__mptcp_move_skbs(msk))) 2095 set_bit(MPTCP_DATA_READY, &msk->flags); 2096 } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) { 2097 /* data to read but mptcp_wait_data() cleared DATA_READY */ 2098 set_bit(MPTCP_DATA_READY, &msk->flags); 2099 } 2100 out_err: 2101 if (cmsg_flags && copied >= 0) { 2102 if (cmsg_flags & MPTCP_CMSG_TS) 2103 tcp_recv_timestamp(msg, sk, &tss); 2104 } 2105 2106 pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d", 2107 msk, test_bit(MPTCP_DATA_READY, &msk->flags), 2108 skb_queue_empty_lockless(&sk->sk_receive_queue), copied); 2109 if (!(flags & MSG_PEEK)) 2110 mptcp_rcv_space_adjust(msk, copied); 2111 2112 release_sock(sk); 2113 return copied; 2114 } 2115 2116 static void mptcp_retransmit_timer(struct timer_list *t) 2117 { 2118 struct inet_connection_sock *icsk = from_timer(icsk, t, 2119 icsk_retransmit_timer); 2120 struct sock *sk = &icsk->icsk_inet.sk; 2121 struct mptcp_sock *msk = mptcp_sk(sk); 2122 2123 bh_lock_sock(sk); 2124 if (!sock_owned_by_user(sk)) { 2125 /* we need a process context to retransmit */ 2126 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) 2127 mptcp_schedule_work(sk); 2128 } else { 2129 /* delegate our work to tcp_release_cb() */ 2130 set_bit(MPTCP_RETRANSMIT, &msk->flags); 2131 } 2132 bh_unlock_sock(sk); 2133 sock_put(sk); 2134 } 2135 2136 static void mptcp_timeout_timer(struct timer_list *t) 2137 { 2138 struct sock *sk = from_timer(sk, t, sk_timer); 2139 2140 mptcp_schedule_work(sk); 2141 sock_put(sk); 2142 } 2143 2144 /* Find an idle subflow. Return NULL if there is unacked data at tcp 2145 * level. 2146 * 2147 * A backup subflow is returned only if that is the only kind available. 2148 */ 2149 static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk) 2150 { 2151 struct mptcp_subflow_context *subflow; 2152 struct sock *backup = NULL; 2153 2154 sock_owned_by_me((const struct sock *)msk); 2155 2156 if (__mptcp_check_fallback(msk)) 2157 return NULL; 2158 2159 mptcp_for_each_subflow(msk, subflow) { 2160 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2161 2162 if (!mptcp_subflow_active(subflow)) 2163 continue; 2164 2165 /* still data outstanding at TCP level? Don't retransmit. */ 2166 if (!tcp_write_queue_empty(ssk)) { 2167 if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss) 2168 continue; 2169 return NULL; 2170 } 2171 2172 if (subflow->backup) { 2173 if (!backup) 2174 backup = ssk; 2175 continue; 2176 } 2177 2178 return ssk; 2179 } 2180 2181 return backup; 2182 } 2183 2184 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk) 2185 { 2186 if (msk->subflow) { 2187 iput(SOCK_INODE(msk->subflow)); 2188 msk->subflow = NULL; 2189 } 2190 } 2191 2192 /* subflow sockets can be either outgoing (connect) or incoming 2193 * (accept). 2194 * 2195 * Outgoing subflows use in-kernel sockets. 2196 * Incoming subflows do not have their own 'struct socket' allocated, 2197 * so we need to use tcp_close() after detaching them from the mptcp 2198 * parent socket. 2199 */ 2200 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2201 struct mptcp_subflow_context *subflow) 2202 { 2203 struct mptcp_sock *msk = mptcp_sk(sk); 2204 2205 list_del(&subflow->node); 2206 2207 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2208 2209 /* if we are invoked by the msk cleanup code, the subflow is 2210 * already orphaned 2211 */ 2212 if (ssk->sk_socket) 2213 sock_orphan(ssk); 2214 2215 subflow->disposable = 1; 2216 2217 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops 2218 * the ssk has been already destroyed, we just need to release the 2219 * reference owned by msk; 2220 */ 2221 if (!inet_csk(ssk)->icsk_ulp_ops) { 2222 kfree_rcu(subflow, rcu); 2223 } else { 2224 /* otherwise tcp will dispose of the ssk and subflow ctx */ 2225 __tcp_close(ssk, 0); 2226 2227 /* close acquired an extra ref */ 2228 __sock_put(ssk); 2229 } 2230 release_sock(ssk); 2231 2232 sock_put(ssk); 2233 2234 if (ssk == msk->last_snd) 2235 msk->last_snd = NULL; 2236 2237 if (ssk == msk->ack_hint) 2238 msk->ack_hint = NULL; 2239 2240 if (ssk == msk->first) 2241 msk->first = NULL; 2242 2243 if (msk->subflow && ssk == msk->subflow->sk) 2244 mptcp_dispose_initial_subflow(msk); 2245 } 2246 2247 void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2248 struct mptcp_subflow_context *subflow) 2249 { 2250 if (sk->sk_state == TCP_ESTABLISHED) 2251 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); 2252 __mptcp_close_ssk(sk, ssk, subflow); 2253 } 2254 2255 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 2256 { 2257 return 0; 2258 } 2259 2260 static void __mptcp_close_subflow(struct mptcp_sock *msk) 2261 { 2262 struct mptcp_subflow_context *subflow, *tmp; 2263 2264 might_sleep(); 2265 2266 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { 2267 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2268 2269 if (inet_sk_state_load(ssk) != TCP_CLOSE) 2270 continue; 2271 2272 /* 'subflow_data_ready' will re-sched once rx queue is empty */ 2273 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) 2274 continue; 2275 2276 mptcp_close_ssk((struct sock *)msk, ssk, subflow); 2277 } 2278 } 2279 2280 static bool mptcp_check_close_timeout(const struct sock *sk) 2281 { 2282 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp; 2283 struct mptcp_subflow_context *subflow; 2284 2285 if (delta >= TCP_TIMEWAIT_LEN) 2286 return true; 2287 2288 /* if all subflows are in closed status don't bother with additional 2289 * timeout 2290 */ 2291 mptcp_for_each_subflow(mptcp_sk(sk), subflow) { 2292 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) != 2293 TCP_CLOSE) 2294 return false; 2295 } 2296 return true; 2297 } 2298 2299 static void mptcp_check_fastclose(struct mptcp_sock *msk) 2300 { 2301 struct mptcp_subflow_context *subflow, *tmp; 2302 struct sock *sk = &msk->sk.icsk_inet.sk; 2303 2304 if (likely(!READ_ONCE(msk->rcv_fastclose))) 2305 return; 2306 2307 mptcp_token_destroy(msk); 2308 2309 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { 2310 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2311 2312 lock_sock(tcp_sk); 2313 if (tcp_sk->sk_state != TCP_CLOSE) { 2314 tcp_send_active_reset(tcp_sk, GFP_ATOMIC); 2315 tcp_set_state(tcp_sk, TCP_CLOSE); 2316 } 2317 release_sock(tcp_sk); 2318 } 2319 2320 inet_sk_state_store(sk, TCP_CLOSE); 2321 sk->sk_shutdown = SHUTDOWN_MASK; 2322 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 2323 set_bit(MPTCP_DATA_READY, &msk->flags); 2324 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); 2325 2326 mptcp_close_wake_up(sk); 2327 } 2328 2329 static void __mptcp_retrans(struct sock *sk) 2330 { 2331 struct mptcp_sock *msk = mptcp_sk(sk); 2332 struct mptcp_sendmsg_info info = {}; 2333 struct mptcp_data_frag *dfrag; 2334 size_t copied = 0; 2335 struct sock *ssk; 2336 int ret; 2337 2338 mptcp_clean_una_wakeup(sk); 2339 dfrag = mptcp_rtx_head(sk); 2340 if (!dfrag) { 2341 if (mptcp_data_fin_enabled(msk)) { 2342 struct inet_connection_sock *icsk = inet_csk(sk); 2343 2344 icsk->icsk_retransmits++; 2345 mptcp_set_datafin_timeout(sk); 2346 mptcp_send_ack(msk); 2347 2348 goto reset_timer; 2349 } 2350 2351 return; 2352 } 2353 2354 ssk = mptcp_subflow_get_retrans(msk); 2355 if (!ssk) 2356 goto reset_timer; 2357 2358 lock_sock(ssk); 2359 2360 /* limit retransmission to the bytes already sent on some subflows */ 2361 info.sent = 0; 2362 info.limit = dfrag->already_sent; 2363 while (info.sent < dfrag->already_sent) { 2364 if (!mptcp_alloc_tx_skb(sk, ssk)) 2365 break; 2366 2367 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 2368 if (ret <= 0) 2369 break; 2370 2371 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 2372 copied += ret; 2373 info.sent += ret; 2374 } 2375 if (copied) 2376 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 2377 info.size_goal); 2378 2379 mptcp_set_timeout(sk, ssk); 2380 release_sock(ssk); 2381 2382 reset_timer: 2383 if (!mptcp_timer_pending(sk)) 2384 mptcp_reset_timer(sk); 2385 } 2386 2387 static void mptcp_worker(struct work_struct *work) 2388 { 2389 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 2390 struct sock *sk = &msk->sk.icsk_inet.sk; 2391 int state; 2392 2393 lock_sock(sk); 2394 state = sk->sk_state; 2395 if (unlikely(state == TCP_CLOSE)) 2396 goto unlock; 2397 2398 mptcp_check_data_fin_ack(sk); 2399 mptcp_flush_join_list(msk); 2400 2401 mptcp_check_fastclose(msk); 2402 2403 if (msk->pm.status) 2404 mptcp_pm_nl_work(msk); 2405 2406 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2407 mptcp_check_for_eof(msk); 2408 2409 __mptcp_check_send_data_fin(sk); 2410 mptcp_check_data_fin(sk); 2411 2412 /* There is no point in keeping around an orphaned sk timedout or 2413 * closed, but we need the msk around to reply to incoming DATA_FIN, 2414 * even if it is orphaned and in FIN_WAIT2 state 2415 */ 2416 if (sock_flag(sk, SOCK_DEAD) && 2417 (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) { 2418 inet_sk_state_store(sk, TCP_CLOSE); 2419 __mptcp_destroy_sock(sk); 2420 goto unlock; 2421 } 2422 2423 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) 2424 __mptcp_close_subflow(msk); 2425 2426 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 2427 __mptcp_retrans(sk); 2428 2429 unlock: 2430 release_sock(sk); 2431 sock_put(sk); 2432 } 2433 2434 static int __mptcp_init_sock(struct sock *sk) 2435 { 2436 struct mptcp_sock *msk = mptcp_sk(sk); 2437 2438 spin_lock_init(&msk->join_list_lock); 2439 2440 INIT_LIST_HEAD(&msk->conn_list); 2441 INIT_LIST_HEAD(&msk->join_list); 2442 INIT_LIST_HEAD(&msk->rtx_queue); 2443 INIT_WORK(&msk->work, mptcp_worker); 2444 __skb_queue_head_init(&msk->receive_queue); 2445 __skb_queue_head_init(&msk->skb_tx_cache); 2446 msk->out_of_order_queue = RB_ROOT; 2447 msk->first_pending = NULL; 2448 msk->wmem_reserved = 0; 2449 msk->rmem_released = 0; 2450 msk->tx_pending_data = 0; 2451 msk->size_goal_cache = TCP_BASE_MSS; 2452 2453 msk->ack_hint = NULL; 2454 msk->first = NULL; 2455 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 2456 2457 mptcp_pm_data_init(msk); 2458 2459 /* re-use the csk retrans timer for MPTCP-level retrans */ 2460 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 2461 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0); 2462 2463 return 0; 2464 } 2465 2466 static int mptcp_init_sock(struct sock *sk) 2467 { 2468 struct inet_connection_sock *icsk = inet_csk(sk); 2469 struct net *net = sock_net(sk); 2470 int ret; 2471 2472 ret = __mptcp_init_sock(sk); 2473 if (ret) 2474 return ret; 2475 2476 if (!mptcp_is_enabled(net)) 2477 return -ENOPROTOOPT; 2478 2479 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 2480 return -ENOMEM; 2481 2482 ret = __mptcp_socket_create(mptcp_sk(sk)); 2483 if (ret) 2484 return ret; 2485 2486 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will 2487 * propagate the correct value 2488 */ 2489 tcp_assign_congestion_control(sk); 2490 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); 2491 2492 /* no need to keep a reference to the ops, the name will suffice */ 2493 tcp_cleanup_congestion_control(sk); 2494 icsk->icsk_ca_ops = NULL; 2495 2496 sk_sockets_allocated_inc(sk); 2497 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1]; 2498 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1]; 2499 2500 return 0; 2501 } 2502 2503 static void __mptcp_clear_xmit(struct sock *sk) 2504 { 2505 struct mptcp_sock *msk = mptcp_sk(sk); 2506 struct mptcp_data_frag *dtmp, *dfrag; 2507 struct sk_buff *skb; 2508 2509 WRITE_ONCE(msk->first_pending, NULL); 2510 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 2511 dfrag_clear(sk, dfrag); 2512 while ((skb = __skb_dequeue(&msk->skb_tx_cache)) != NULL) { 2513 sk->sk_forward_alloc += skb->truesize; 2514 kfree_skb(skb); 2515 } 2516 } 2517 2518 static void mptcp_cancel_work(struct sock *sk) 2519 { 2520 struct mptcp_sock *msk = mptcp_sk(sk); 2521 2522 if (cancel_work_sync(&msk->work)) 2523 __sock_put(sk); 2524 } 2525 2526 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 2527 { 2528 lock_sock(ssk); 2529 2530 switch (ssk->sk_state) { 2531 case TCP_LISTEN: 2532 if (!(how & RCV_SHUTDOWN)) 2533 break; 2534 fallthrough; 2535 case TCP_SYN_SENT: 2536 tcp_disconnect(ssk, O_NONBLOCK); 2537 break; 2538 default: 2539 if (__mptcp_check_fallback(mptcp_sk(sk))) { 2540 pr_debug("Fallback"); 2541 ssk->sk_shutdown |= how; 2542 tcp_shutdown(ssk, how); 2543 } else { 2544 pr_debug("Sending DATA_FIN on subflow %p", ssk); 2545 mptcp_set_timeout(sk, ssk); 2546 tcp_send_ack(ssk); 2547 if (!mptcp_timer_pending(sk)) 2548 mptcp_reset_timer(sk); 2549 } 2550 break; 2551 } 2552 2553 release_sock(ssk); 2554 } 2555 2556 static const unsigned char new_state[16] = { 2557 /* current state: new state: action: */ 2558 [0 /* (Invalid) */] = TCP_CLOSE, 2559 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2560 [TCP_SYN_SENT] = TCP_CLOSE, 2561 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2562 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 2563 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 2564 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 2565 [TCP_CLOSE] = TCP_CLOSE, 2566 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 2567 [TCP_LAST_ACK] = TCP_LAST_ACK, 2568 [TCP_LISTEN] = TCP_CLOSE, 2569 [TCP_CLOSING] = TCP_CLOSING, 2570 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 2571 }; 2572 2573 static int mptcp_close_state(struct sock *sk) 2574 { 2575 int next = (int)new_state[sk->sk_state]; 2576 int ns = next & TCP_STATE_MASK; 2577 2578 inet_sk_state_store(sk, ns); 2579 2580 return next & TCP_ACTION_FIN; 2581 } 2582 2583 static void __mptcp_check_send_data_fin(struct sock *sk) 2584 { 2585 struct mptcp_subflow_context *subflow; 2586 struct mptcp_sock *msk = mptcp_sk(sk); 2587 2588 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", 2589 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), 2590 msk->snd_nxt, msk->write_seq); 2591 2592 /* we still need to enqueue subflows or not really shutting down, 2593 * skip this 2594 */ 2595 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || 2596 mptcp_send_head(sk)) 2597 return; 2598 2599 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2600 2601 /* fallback socket will not get data_fin/ack, can move to the next 2602 * state now 2603 */ 2604 if (__mptcp_check_fallback(msk)) { 2605 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) { 2606 inet_sk_state_store(sk, TCP_CLOSE); 2607 mptcp_close_wake_up(sk); 2608 } else if (sk->sk_state == TCP_FIN_WAIT1) { 2609 inet_sk_state_store(sk, TCP_FIN_WAIT2); 2610 } 2611 } 2612 2613 mptcp_flush_join_list(msk); 2614 mptcp_for_each_subflow(msk, subflow) { 2615 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2616 2617 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); 2618 } 2619 } 2620 2621 static void __mptcp_wr_shutdown(struct sock *sk) 2622 { 2623 struct mptcp_sock *msk = mptcp_sk(sk); 2624 2625 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", 2626 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, 2627 !!mptcp_send_head(sk)); 2628 2629 /* will be ignored by fallback sockets */ 2630 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2631 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2632 2633 __mptcp_check_send_data_fin(sk); 2634 } 2635 2636 static void __mptcp_destroy_sock(struct sock *sk) 2637 { 2638 struct mptcp_subflow_context *subflow, *tmp; 2639 struct mptcp_sock *msk = mptcp_sk(sk); 2640 LIST_HEAD(conn_list); 2641 2642 pr_debug("msk=%p", msk); 2643 2644 might_sleep(); 2645 2646 /* be sure to always acquire the join list lock, to sync vs 2647 * mptcp_finish_join(). 2648 */ 2649 spin_lock_bh(&msk->join_list_lock); 2650 list_splice_tail_init(&msk->join_list, &msk->conn_list); 2651 spin_unlock_bh(&msk->join_list_lock); 2652 list_splice_init(&msk->conn_list, &conn_list); 2653 2654 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); 2655 sk_stop_timer(sk, &sk->sk_timer); 2656 msk->pm.status = 0; 2657 2658 list_for_each_entry_safe(subflow, tmp, &conn_list, node) { 2659 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2660 __mptcp_close_ssk(sk, ssk, subflow); 2661 } 2662 2663 sk->sk_prot->destroy(sk); 2664 2665 WARN_ON_ONCE(msk->wmem_reserved); 2666 WARN_ON_ONCE(msk->rmem_released); 2667 sk_stream_kill_queues(sk); 2668 xfrm_sk_free_policy(sk); 2669 2670 sk_refcnt_debug_release(sk); 2671 mptcp_dispose_initial_subflow(msk); 2672 sock_put(sk); 2673 } 2674 2675 static void mptcp_close(struct sock *sk, long timeout) 2676 { 2677 struct mptcp_subflow_context *subflow; 2678 bool do_cancel_work = false; 2679 2680 lock_sock(sk); 2681 sk->sk_shutdown = SHUTDOWN_MASK; 2682 2683 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { 2684 inet_sk_state_store(sk, TCP_CLOSE); 2685 goto cleanup; 2686 } 2687 2688 if (mptcp_close_state(sk)) 2689 __mptcp_wr_shutdown(sk); 2690 2691 sk_stream_wait_close(sk, timeout); 2692 2693 cleanup: 2694 /* orphan all the subflows */ 2695 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32; 2696 mptcp_for_each_subflow(mptcp_sk(sk), subflow) { 2697 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2698 bool slow = lock_sock_fast(ssk); 2699 2700 sock_orphan(ssk); 2701 unlock_sock_fast(ssk, slow); 2702 } 2703 sock_orphan(sk); 2704 2705 sock_hold(sk); 2706 pr_debug("msk=%p state=%d", sk, sk->sk_state); 2707 if (sk->sk_state == TCP_CLOSE) { 2708 __mptcp_destroy_sock(sk); 2709 do_cancel_work = true; 2710 } else { 2711 sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN); 2712 } 2713 release_sock(sk); 2714 if (do_cancel_work) 2715 mptcp_cancel_work(sk); 2716 2717 if (mptcp_sk(sk)->token) 2718 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL); 2719 2720 sock_put(sk); 2721 } 2722 2723 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 2724 { 2725 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2726 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 2727 struct ipv6_pinfo *msk6 = inet6_sk(msk); 2728 2729 msk->sk_v6_daddr = ssk->sk_v6_daddr; 2730 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 2731 2732 if (msk6 && ssk6) { 2733 msk6->saddr = ssk6->saddr; 2734 msk6->flow_label = ssk6->flow_label; 2735 } 2736 #endif 2737 2738 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 2739 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 2740 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 2741 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 2742 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 2743 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 2744 } 2745 2746 static int mptcp_disconnect(struct sock *sk, int flags) 2747 { 2748 struct mptcp_subflow_context *subflow; 2749 struct mptcp_sock *msk = mptcp_sk(sk); 2750 2751 mptcp_do_flush_join_list(msk); 2752 2753 mptcp_for_each_subflow(msk, subflow) { 2754 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2755 2756 lock_sock(ssk); 2757 tcp_disconnect(ssk, flags); 2758 release_sock(ssk); 2759 } 2760 return 0; 2761 } 2762 2763 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2764 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 2765 { 2766 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 2767 2768 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 2769 } 2770 #endif 2771 2772 struct sock *mptcp_sk_clone(const struct sock *sk, 2773 const struct mptcp_options_received *mp_opt, 2774 struct request_sock *req) 2775 { 2776 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 2777 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 2778 struct mptcp_sock *msk; 2779 u64 ack_seq; 2780 2781 if (!nsk) 2782 return NULL; 2783 2784 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2785 if (nsk->sk_family == AF_INET6) 2786 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 2787 #endif 2788 2789 __mptcp_init_sock(nsk); 2790 2791 msk = mptcp_sk(nsk); 2792 msk->local_key = subflow_req->local_key; 2793 msk->token = subflow_req->token; 2794 msk->subflow = NULL; 2795 WRITE_ONCE(msk->fully_established, false); 2796 2797 msk->write_seq = subflow_req->idsn + 1; 2798 msk->snd_nxt = msk->write_seq; 2799 msk->snd_una = msk->write_seq; 2800 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; 2801 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; 2802 2803 if (mp_opt->mp_capable) { 2804 msk->can_ack = true; 2805 msk->remote_key = mp_opt->sndr_key; 2806 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq); 2807 ack_seq++; 2808 WRITE_ONCE(msk->ack_seq, ack_seq); 2809 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 2810 } 2811 2812 sock_reset_flag(nsk, SOCK_RCU_FREE); 2813 /* will be fully established after successful MPC subflow creation */ 2814 inet_sk_state_store(nsk, TCP_SYN_RECV); 2815 2816 security_inet_csk_clone(nsk, req); 2817 bh_unlock_sock(nsk); 2818 2819 /* keep a single reference */ 2820 __sock_put(nsk); 2821 return nsk; 2822 } 2823 2824 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 2825 { 2826 const struct tcp_sock *tp = tcp_sk(ssk); 2827 2828 msk->rcvq_space.copied = 0; 2829 msk->rcvq_space.rtt_us = 0; 2830 2831 msk->rcvq_space.time = tp->tcp_mstamp; 2832 2833 /* initial rcv_space offering made to peer */ 2834 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 2835 TCP_INIT_CWND * tp->advmss); 2836 if (msk->rcvq_space.space == 0) 2837 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 2838 2839 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); 2840 } 2841 2842 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 2843 bool kern) 2844 { 2845 struct mptcp_sock *msk = mptcp_sk(sk); 2846 struct socket *listener; 2847 struct sock *newsk; 2848 2849 listener = __mptcp_nmpc_socket(msk); 2850 if (WARN_ON_ONCE(!listener)) { 2851 *err = -EINVAL; 2852 return NULL; 2853 } 2854 2855 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); 2856 newsk = inet_csk_accept(listener->sk, flags, err, kern); 2857 if (!newsk) 2858 return NULL; 2859 2860 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); 2861 if (sk_is_mptcp(newsk)) { 2862 struct mptcp_subflow_context *subflow; 2863 struct sock *new_mptcp_sock; 2864 2865 subflow = mptcp_subflow_ctx(newsk); 2866 new_mptcp_sock = subflow->conn; 2867 2868 /* is_mptcp should be false if subflow->conn is missing, see 2869 * subflow_syn_recv_sock() 2870 */ 2871 if (WARN_ON_ONCE(!new_mptcp_sock)) { 2872 tcp_sk(newsk)->is_mptcp = 0; 2873 return newsk; 2874 } 2875 2876 /* acquire the 2nd reference for the owning socket */ 2877 sock_hold(new_mptcp_sock); 2878 newsk = new_mptcp_sock; 2879 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 2880 } else { 2881 MPTCP_INC_STATS(sock_net(sk), 2882 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 2883 } 2884 2885 return newsk; 2886 } 2887 2888 void mptcp_destroy_common(struct mptcp_sock *msk) 2889 { 2890 struct sock *sk = (struct sock *)msk; 2891 2892 __mptcp_clear_xmit(sk); 2893 2894 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ 2895 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); 2896 2897 skb_rbtree_purge(&msk->out_of_order_queue); 2898 mptcp_token_destroy(msk); 2899 mptcp_pm_free_anno_list(msk); 2900 } 2901 2902 static void mptcp_destroy(struct sock *sk) 2903 { 2904 struct mptcp_sock *msk = mptcp_sk(sk); 2905 2906 mptcp_destroy_common(msk); 2907 sk_sockets_allocated_dec(sk); 2908 } 2909 2910 void __mptcp_data_acked(struct sock *sk) 2911 { 2912 if (!sock_owned_by_user(sk)) 2913 __mptcp_clean_una(sk); 2914 else 2915 set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags); 2916 2917 if (mptcp_pending_data_fin_ack(sk)) 2918 mptcp_schedule_work(sk); 2919 } 2920 2921 void __mptcp_check_push(struct sock *sk, struct sock *ssk) 2922 { 2923 if (!mptcp_send_head(sk)) 2924 return; 2925 2926 if (!sock_owned_by_user(sk)) { 2927 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk)); 2928 2929 if (xmit_ssk == ssk) 2930 __mptcp_subflow_push_pending(sk, ssk); 2931 else if (xmit_ssk) 2932 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk)); 2933 } else { 2934 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); 2935 } 2936 } 2937 2938 /* processes deferred events and flush wmem */ 2939 static void mptcp_release_cb(struct sock *sk) 2940 { 2941 for (;;) { 2942 unsigned long flags = 0; 2943 2944 if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) 2945 flags |= BIT(MPTCP_PUSH_PENDING); 2946 if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags)) 2947 flags |= BIT(MPTCP_RETRANSMIT); 2948 if (!flags) 2949 break; 2950 2951 /* the following actions acquire the subflow socket lock 2952 * 2953 * 1) can't be invoked in atomic scope 2954 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX 2955 * datapath acquires the msk socket spinlock while helding 2956 * the subflow socket lock 2957 */ 2958 2959 spin_unlock_bh(&sk->sk_lock.slock); 2960 if (flags & BIT(MPTCP_PUSH_PENDING)) 2961 __mptcp_push_pending(sk, 0); 2962 if (flags & BIT(MPTCP_RETRANSMIT)) 2963 __mptcp_retrans(sk); 2964 2965 cond_resched(); 2966 spin_lock_bh(&sk->sk_lock.slock); 2967 } 2968 2969 if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) 2970 __mptcp_clean_una_wakeup(sk); 2971 if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags)) 2972 __mptcp_error_report(sk); 2973 2974 /* push_pending may touch wmem_reserved, ensure we do the cleanup 2975 * later 2976 */ 2977 __mptcp_update_wmem(sk); 2978 __mptcp_update_rmem(sk); 2979 } 2980 2981 void mptcp_subflow_process_delegated(struct sock *ssk) 2982 { 2983 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 2984 struct sock *sk = subflow->conn; 2985 2986 mptcp_data_lock(sk); 2987 if (!sock_owned_by_user(sk)) 2988 __mptcp_subflow_push_pending(sk, ssk); 2989 else 2990 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); 2991 mptcp_data_unlock(sk); 2992 mptcp_subflow_delegated_done(subflow); 2993 } 2994 2995 static int mptcp_hash(struct sock *sk) 2996 { 2997 /* should never be called, 2998 * we hash the TCP subflows not the master socket 2999 */ 3000 WARN_ON_ONCE(1); 3001 return 0; 3002 } 3003 3004 static void mptcp_unhash(struct sock *sk) 3005 { 3006 /* called from sk_common_release(), but nothing to do here */ 3007 } 3008 3009 static int mptcp_get_port(struct sock *sk, unsigned short snum) 3010 { 3011 struct mptcp_sock *msk = mptcp_sk(sk); 3012 struct socket *ssock; 3013 3014 ssock = __mptcp_nmpc_socket(msk); 3015 pr_debug("msk=%p, subflow=%p", msk, ssock); 3016 if (WARN_ON_ONCE(!ssock)) 3017 return -EINVAL; 3018 3019 return inet_csk_get_port(ssock->sk, snum); 3020 } 3021 3022 void mptcp_finish_connect(struct sock *ssk) 3023 { 3024 struct mptcp_subflow_context *subflow; 3025 struct mptcp_sock *msk; 3026 struct sock *sk; 3027 u64 ack_seq; 3028 3029 subflow = mptcp_subflow_ctx(ssk); 3030 sk = subflow->conn; 3031 msk = mptcp_sk(sk); 3032 3033 pr_debug("msk=%p, token=%u", sk, subflow->token); 3034 3035 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq); 3036 ack_seq++; 3037 subflow->map_seq = ack_seq; 3038 subflow->map_subflow_seq = 1; 3039 3040 /* the socket is not connected yet, no msk/subflow ops can access/race 3041 * accessing the field below 3042 */ 3043 WRITE_ONCE(msk->remote_key, subflow->remote_key); 3044 WRITE_ONCE(msk->local_key, subflow->local_key); 3045 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 3046 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 3047 WRITE_ONCE(msk->ack_seq, ack_seq); 3048 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 3049 WRITE_ONCE(msk->can_ack, 1); 3050 WRITE_ONCE(msk->snd_una, msk->write_seq); 3051 3052 mptcp_pm_new_connection(msk, ssk, 0); 3053 3054 mptcp_rcv_space_init(msk, ssk); 3055 } 3056 3057 void mptcp_sock_graft(struct sock *sk, struct socket *parent) 3058 { 3059 write_lock_bh(&sk->sk_callback_lock); 3060 rcu_assign_pointer(sk->sk_wq, &parent->wq); 3061 sk_set_socket(sk, parent); 3062 sk->sk_uid = SOCK_INODE(parent)->i_uid; 3063 write_unlock_bh(&sk->sk_callback_lock); 3064 } 3065 3066 bool mptcp_finish_join(struct sock *ssk) 3067 { 3068 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3069 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 3070 struct sock *parent = (void *)msk; 3071 struct socket *parent_sock; 3072 bool ret; 3073 3074 pr_debug("msk=%p, subflow=%p", msk, subflow); 3075 3076 /* mptcp socket already closing? */ 3077 if (!mptcp_is_fully_established(parent)) { 3078 subflow->reset_reason = MPTCP_RST_EMPTCP; 3079 return false; 3080 } 3081 3082 if (!msk->pm.server_side) 3083 goto out; 3084 3085 if (!mptcp_pm_allow_new_subflow(msk)) { 3086 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3087 return false; 3088 } 3089 3090 /* active connections are already on conn_list, and we can't acquire 3091 * msk lock here. 3092 * use the join list lock as synchronization point and double-check 3093 * msk status to avoid racing with __mptcp_destroy_sock() 3094 */ 3095 spin_lock_bh(&msk->join_list_lock); 3096 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED; 3097 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) { 3098 list_add_tail(&subflow->node, &msk->join_list); 3099 sock_hold(ssk); 3100 } 3101 spin_unlock_bh(&msk->join_list_lock); 3102 if (!ret) { 3103 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3104 return false; 3105 } 3106 3107 /* attach to msk socket only after we are sure he will deal with us 3108 * at close time 3109 */ 3110 parent_sock = READ_ONCE(parent->sk_socket); 3111 if (parent_sock && !ssk->sk_socket) 3112 mptcp_sock_graft(ssk, parent_sock); 3113 subflow->map_seq = READ_ONCE(msk->ack_seq); 3114 out: 3115 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); 3116 return true; 3117 } 3118 3119 static void mptcp_shutdown(struct sock *sk, int how) 3120 { 3121 pr_debug("sk=%p, how=%d", sk, how); 3122 3123 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) 3124 __mptcp_wr_shutdown(sk); 3125 } 3126 3127 static struct proto mptcp_prot = { 3128 .name = "MPTCP", 3129 .owner = THIS_MODULE, 3130 .init = mptcp_init_sock, 3131 .disconnect = mptcp_disconnect, 3132 .close = mptcp_close, 3133 .accept = mptcp_accept, 3134 .setsockopt = mptcp_setsockopt, 3135 .getsockopt = mptcp_getsockopt, 3136 .shutdown = mptcp_shutdown, 3137 .destroy = mptcp_destroy, 3138 .sendmsg = mptcp_sendmsg, 3139 .recvmsg = mptcp_recvmsg, 3140 .release_cb = mptcp_release_cb, 3141 .hash = mptcp_hash, 3142 .unhash = mptcp_unhash, 3143 .get_port = mptcp_get_port, 3144 .sockets_allocated = &mptcp_sockets_allocated, 3145 .memory_allocated = &tcp_memory_allocated, 3146 .memory_pressure = &tcp_memory_pressure, 3147 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3148 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3149 .sysctl_mem = sysctl_tcp_mem, 3150 .obj_size = sizeof(struct mptcp_sock), 3151 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3152 .no_autobind = true, 3153 }; 3154 3155 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 3156 { 3157 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3158 struct socket *ssock; 3159 int err; 3160 3161 lock_sock(sock->sk); 3162 ssock = __mptcp_nmpc_socket(msk); 3163 if (!ssock) { 3164 err = -EINVAL; 3165 goto unlock; 3166 } 3167 3168 err = ssock->ops->bind(ssock, uaddr, addr_len); 3169 if (!err) 3170 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3171 3172 unlock: 3173 release_sock(sock->sk); 3174 return err; 3175 } 3176 3177 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 3178 struct mptcp_subflow_context *subflow) 3179 { 3180 subflow->request_mptcp = 0; 3181 __mptcp_do_fallback(msk); 3182 } 3183 3184 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, 3185 int addr_len, int flags) 3186 { 3187 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3188 struct mptcp_subflow_context *subflow; 3189 struct socket *ssock; 3190 int err; 3191 3192 lock_sock(sock->sk); 3193 if (sock->state != SS_UNCONNECTED && msk->subflow) { 3194 /* pending connection or invalid state, let existing subflow 3195 * cope with that 3196 */ 3197 ssock = msk->subflow; 3198 goto do_connect; 3199 } 3200 3201 ssock = __mptcp_nmpc_socket(msk); 3202 if (!ssock) { 3203 err = -EINVAL; 3204 goto unlock; 3205 } 3206 3207 mptcp_token_destroy(msk); 3208 inet_sk_state_store(sock->sk, TCP_SYN_SENT); 3209 subflow = mptcp_subflow_ctx(ssock->sk); 3210 #ifdef CONFIG_TCP_MD5SIG 3211 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 3212 * TCP option space. 3213 */ 3214 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info)) 3215 mptcp_subflow_early_fallback(msk, subflow); 3216 #endif 3217 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) { 3218 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT); 3219 mptcp_subflow_early_fallback(msk, subflow); 3220 } 3221 if (likely(!__mptcp_check_fallback(msk))) 3222 MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE); 3223 3224 do_connect: 3225 err = ssock->ops->connect(ssock, uaddr, addr_len, flags); 3226 sock->state = ssock->state; 3227 3228 /* on successful connect, the msk state will be moved to established by 3229 * subflow_finish_connect() 3230 */ 3231 if (!err || err == -EINPROGRESS) 3232 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3233 else 3234 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 3235 3236 unlock: 3237 release_sock(sock->sk); 3238 return err; 3239 } 3240 3241 static int mptcp_listen(struct socket *sock, int backlog) 3242 { 3243 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3244 struct socket *ssock; 3245 int err; 3246 3247 pr_debug("msk=%p", msk); 3248 3249 lock_sock(sock->sk); 3250 ssock = __mptcp_nmpc_socket(msk); 3251 if (!ssock) { 3252 err = -EINVAL; 3253 goto unlock; 3254 } 3255 3256 mptcp_token_destroy(msk); 3257 inet_sk_state_store(sock->sk, TCP_LISTEN); 3258 sock_set_flag(sock->sk, SOCK_RCU_FREE); 3259 3260 err = ssock->ops->listen(ssock, backlog); 3261 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 3262 if (!err) 3263 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3264 3265 unlock: 3266 release_sock(sock->sk); 3267 return err; 3268 } 3269 3270 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 3271 int flags, bool kern) 3272 { 3273 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3274 struct socket *ssock; 3275 int err; 3276 3277 pr_debug("msk=%p", msk); 3278 3279 lock_sock(sock->sk); 3280 if (sock->sk->sk_state != TCP_LISTEN) 3281 goto unlock_fail; 3282 3283 ssock = __mptcp_nmpc_socket(msk); 3284 if (!ssock) 3285 goto unlock_fail; 3286 3287 clear_bit(MPTCP_DATA_READY, &msk->flags); 3288 sock_hold(ssock->sk); 3289 release_sock(sock->sk); 3290 3291 err = ssock->ops->accept(sock, newsock, flags, kern); 3292 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { 3293 struct mptcp_sock *msk = mptcp_sk(newsock->sk); 3294 struct mptcp_subflow_context *subflow; 3295 struct sock *newsk = newsock->sk; 3296 3297 lock_sock(newsk); 3298 3299 /* PM/worker can now acquire the first subflow socket 3300 * lock without racing with listener queue cleanup, 3301 * we can notify it, if needed. 3302 * 3303 * Even if remote has reset the initial subflow by now 3304 * the refcnt is still at least one. 3305 */ 3306 subflow = mptcp_subflow_ctx(msk->first); 3307 list_add(&subflow->node, &msk->conn_list); 3308 sock_hold(msk->first); 3309 if (mptcp_is_fully_established(newsk)) 3310 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL); 3311 3312 mptcp_copy_inaddrs(newsk, msk->first); 3313 mptcp_rcv_space_init(msk, msk->first); 3314 mptcp_propagate_sndbuf(newsk, msk->first); 3315 3316 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 3317 * This is needed so NOSPACE flag can be set from tcp stack. 3318 */ 3319 mptcp_flush_join_list(msk); 3320 mptcp_for_each_subflow(msk, subflow) { 3321 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3322 3323 if (!ssk->sk_socket) 3324 mptcp_sock_graft(ssk, newsock); 3325 } 3326 release_sock(newsk); 3327 } 3328 3329 if (inet_csk_listen_poll(ssock->sk)) 3330 set_bit(MPTCP_DATA_READY, &msk->flags); 3331 sock_put(ssock->sk); 3332 return err; 3333 3334 unlock_fail: 3335 release_sock(sock->sk); 3336 return -EINVAL; 3337 } 3338 3339 static __poll_t mptcp_check_readable(struct mptcp_sock *msk) 3340 { 3341 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 3342 0; 3343 } 3344 3345 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) 3346 { 3347 struct sock *sk = (struct sock *)msk; 3348 3349 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 3350 return EPOLLOUT | EPOLLWRNORM; 3351 3352 if (sk_stream_is_writeable(sk)) 3353 return EPOLLOUT | EPOLLWRNORM; 3354 3355 mptcp_set_nospace(sk); 3356 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 3357 if (sk_stream_is_writeable(sk)) 3358 return EPOLLOUT | EPOLLWRNORM; 3359 3360 return 0; 3361 } 3362 3363 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 3364 struct poll_table_struct *wait) 3365 { 3366 struct sock *sk = sock->sk; 3367 struct mptcp_sock *msk; 3368 __poll_t mask = 0; 3369 int state; 3370 3371 msk = mptcp_sk(sk); 3372 sock_poll_wait(file, sock, wait); 3373 3374 state = inet_sk_state_load(sk); 3375 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); 3376 if (state == TCP_LISTEN) 3377 return mptcp_check_readable(msk); 3378 3379 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 3380 mask |= mptcp_check_readable(msk); 3381 mask |= mptcp_check_writeable(msk); 3382 } 3383 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) 3384 mask |= EPOLLHUP; 3385 if (sk->sk_shutdown & RCV_SHUTDOWN) 3386 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 3387 3388 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 3389 smp_rmb(); 3390 if (sk->sk_err) 3391 mask |= EPOLLERR; 3392 3393 return mask; 3394 } 3395 3396 static const struct proto_ops mptcp_stream_ops = { 3397 .family = PF_INET, 3398 .owner = THIS_MODULE, 3399 .release = inet_release, 3400 .bind = mptcp_bind, 3401 .connect = mptcp_stream_connect, 3402 .socketpair = sock_no_socketpair, 3403 .accept = mptcp_stream_accept, 3404 .getname = inet_getname, 3405 .poll = mptcp_poll, 3406 .ioctl = inet_ioctl, 3407 .gettstamp = sock_gettstamp, 3408 .listen = mptcp_listen, 3409 .shutdown = inet_shutdown, 3410 .setsockopt = sock_common_setsockopt, 3411 .getsockopt = sock_common_getsockopt, 3412 .sendmsg = inet_sendmsg, 3413 .recvmsg = inet_recvmsg, 3414 .mmap = sock_no_mmap, 3415 .sendpage = inet_sendpage, 3416 }; 3417 3418 static struct inet_protosw mptcp_protosw = { 3419 .type = SOCK_STREAM, 3420 .protocol = IPPROTO_MPTCP, 3421 .prot = &mptcp_prot, 3422 .ops = &mptcp_stream_ops, 3423 .flags = INET_PROTOSW_ICSK, 3424 }; 3425 3426 static int mptcp_napi_poll(struct napi_struct *napi, int budget) 3427 { 3428 struct mptcp_delegated_action *delegated; 3429 struct mptcp_subflow_context *subflow; 3430 int work_done = 0; 3431 3432 delegated = container_of(napi, struct mptcp_delegated_action, napi); 3433 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { 3434 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3435 3436 bh_lock_sock_nested(ssk); 3437 if (!sock_owned_by_user(ssk) && 3438 mptcp_subflow_has_delegated_action(subflow)) 3439 mptcp_subflow_process_delegated(ssk); 3440 /* ... elsewhere tcp_release_cb_override already processed 3441 * the action or will do at next release_sock(). 3442 * In both case must dequeue the subflow here - on the same 3443 * CPU that scheduled it. 3444 */ 3445 bh_unlock_sock(ssk); 3446 sock_put(ssk); 3447 3448 if (++work_done == budget) 3449 return budget; 3450 } 3451 3452 /* always provide a 0 'work_done' argument, so that napi_complete_done 3453 * will not try accessing the NULL napi->dev ptr 3454 */ 3455 napi_complete_done(napi, 0); 3456 return work_done; 3457 } 3458 3459 void __init mptcp_proto_init(void) 3460 { 3461 struct mptcp_delegated_action *delegated; 3462 int cpu; 3463 3464 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 3465 3466 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 3467 panic("Failed to allocate MPTCP pcpu counter\n"); 3468 3469 init_dummy_netdev(&mptcp_napi_dev); 3470 for_each_possible_cpu(cpu) { 3471 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); 3472 INIT_LIST_HEAD(&delegated->head); 3473 netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll, 3474 NAPI_POLL_WEIGHT); 3475 napi_enable(&delegated->napi); 3476 } 3477 3478 mptcp_subflow_init(); 3479 mptcp_pm_init(); 3480 mptcp_token_init(); 3481 3482 if (proto_register(&mptcp_prot, 1) != 0) 3483 panic("Failed to register MPTCP proto.\n"); 3484 3485 inet_register_protosw(&mptcp_protosw); 3486 3487 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 3488 } 3489 3490 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3491 static const struct proto_ops mptcp_v6_stream_ops = { 3492 .family = PF_INET6, 3493 .owner = THIS_MODULE, 3494 .release = inet6_release, 3495 .bind = mptcp_bind, 3496 .connect = mptcp_stream_connect, 3497 .socketpair = sock_no_socketpair, 3498 .accept = mptcp_stream_accept, 3499 .getname = inet6_getname, 3500 .poll = mptcp_poll, 3501 .ioctl = inet6_ioctl, 3502 .gettstamp = sock_gettstamp, 3503 .listen = mptcp_listen, 3504 .shutdown = inet_shutdown, 3505 .setsockopt = sock_common_setsockopt, 3506 .getsockopt = sock_common_getsockopt, 3507 .sendmsg = inet6_sendmsg, 3508 .recvmsg = inet6_recvmsg, 3509 .mmap = sock_no_mmap, 3510 .sendpage = inet_sendpage, 3511 #ifdef CONFIG_COMPAT 3512 .compat_ioctl = inet6_compat_ioctl, 3513 #endif 3514 }; 3515 3516 static struct proto mptcp_v6_prot; 3517 3518 static void mptcp_v6_destroy(struct sock *sk) 3519 { 3520 mptcp_destroy(sk); 3521 inet6_destroy_sock(sk); 3522 } 3523 3524 static struct inet_protosw mptcp_v6_protosw = { 3525 .type = SOCK_STREAM, 3526 .protocol = IPPROTO_MPTCP, 3527 .prot = &mptcp_v6_prot, 3528 .ops = &mptcp_v6_stream_ops, 3529 .flags = INET_PROTOSW_ICSK, 3530 }; 3531 3532 int __init mptcp_proto_v6_init(void) 3533 { 3534 int err; 3535 3536 mptcp_v6_prot = mptcp_prot; 3537 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 3538 mptcp_v6_prot.slab = NULL; 3539 mptcp_v6_prot.destroy = mptcp_v6_destroy; 3540 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 3541 3542 err = proto_register(&mptcp_v6_prot, 1); 3543 if (err) 3544 return err; 3545 3546 err = inet6_register_protosw(&mptcp_v6_protosw); 3547 if (err) 3548 proto_unregister(&mptcp_v6_prot); 3549 3550 return err; 3551 } 3552 #endif 3553