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