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 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 883 const struct page_frag *pfrag, 884 const struct mptcp_data_frag *df) 885 { 886 return df && pfrag->page == df->page && 887 pfrag->size - pfrag->offset > 0 && 888 df->data_seq + df->data_len == msk->write_seq; 889 } 890 891 static int mptcp_wmem_with_overhead(struct sock *sk, int size) 892 { 893 struct mptcp_sock *msk = mptcp_sk(sk); 894 int ret, skbs; 895 896 ret = size + ((sizeof(struct mptcp_data_frag) * size) >> PAGE_SHIFT); 897 skbs = (msk->tx_pending_data + size) / msk->size_goal_cache; 898 if (skbs < msk->skb_tx_cache.qlen) 899 return ret; 900 901 return ret + (skbs - msk->skb_tx_cache.qlen) * SKB_TRUESIZE(MAX_TCP_HEADER); 902 } 903 904 static void __mptcp_wmem_reserve(struct sock *sk, int size) 905 { 906 int amount = mptcp_wmem_with_overhead(sk, size); 907 struct mptcp_sock *msk = mptcp_sk(sk); 908 909 WARN_ON_ONCE(msk->wmem_reserved); 910 if (WARN_ON_ONCE(amount < 0)) 911 amount = 0; 912 913 if (amount <= sk->sk_forward_alloc) 914 goto reserve; 915 916 /* under memory pressure try to reserve at most a single page 917 * otherwise try to reserve the full estimate and fallback 918 * to a single page before entering the error path 919 */ 920 if ((tcp_under_memory_pressure(sk) && amount > PAGE_SIZE) || 921 !sk_wmem_schedule(sk, amount)) { 922 if (amount <= PAGE_SIZE) 923 goto nomem; 924 925 amount = PAGE_SIZE; 926 if (!sk_wmem_schedule(sk, amount)) 927 goto nomem; 928 } 929 930 reserve: 931 msk->wmem_reserved = amount; 932 sk->sk_forward_alloc -= amount; 933 return; 934 935 nomem: 936 /* we will wait for memory on next allocation */ 937 msk->wmem_reserved = -1; 938 } 939 940 static void __mptcp_update_wmem(struct sock *sk) 941 { 942 struct mptcp_sock *msk = mptcp_sk(sk); 943 944 if (!msk->wmem_reserved) 945 return; 946 947 if (msk->wmem_reserved < 0) 948 msk->wmem_reserved = 0; 949 if (msk->wmem_reserved > 0) { 950 sk->sk_forward_alloc += msk->wmem_reserved; 951 msk->wmem_reserved = 0; 952 } 953 } 954 955 static bool mptcp_wmem_alloc(struct sock *sk, int size) 956 { 957 struct mptcp_sock *msk = mptcp_sk(sk); 958 959 /* check for pre-existing error condition */ 960 if (msk->wmem_reserved < 0) 961 return false; 962 963 if (msk->wmem_reserved >= size) 964 goto account; 965 966 mptcp_data_lock(sk); 967 if (!sk_wmem_schedule(sk, size)) { 968 mptcp_data_unlock(sk); 969 return false; 970 } 971 972 sk->sk_forward_alloc -= size; 973 msk->wmem_reserved += size; 974 mptcp_data_unlock(sk); 975 976 account: 977 msk->wmem_reserved -= size; 978 return true; 979 } 980 981 static void mptcp_wmem_uncharge(struct sock *sk, int size) 982 { 983 struct mptcp_sock *msk = mptcp_sk(sk); 984 985 if (msk->wmem_reserved < 0) 986 msk->wmem_reserved = 0; 987 msk->wmem_reserved += size; 988 } 989 990 static void mptcp_mem_reclaim_partial(struct sock *sk) 991 { 992 struct mptcp_sock *msk = mptcp_sk(sk); 993 994 /* if we are experiencing a transint allocation error, 995 * the forward allocation memory has been already 996 * released 997 */ 998 if (msk->wmem_reserved < 0) 999 return; 1000 1001 mptcp_data_lock(sk); 1002 sk->sk_forward_alloc += msk->wmem_reserved; 1003 sk_mem_reclaim_partial(sk); 1004 msk->wmem_reserved = sk->sk_forward_alloc; 1005 sk->sk_forward_alloc = 0; 1006 mptcp_data_unlock(sk); 1007 } 1008 1009 static void dfrag_uncharge(struct sock *sk, int len) 1010 { 1011 sk_mem_uncharge(sk, len); 1012 sk_wmem_queued_add(sk, -len); 1013 } 1014 1015 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 1016 { 1017 int len = dfrag->data_len + dfrag->overhead; 1018 1019 list_del(&dfrag->list); 1020 dfrag_uncharge(sk, len); 1021 put_page(dfrag->page); 1022 } 1023 1024 static void __mptcp_clean_una(struct sock *sk) 1025 { 1026 struct mptcp_sock *msk = mptcp_sk(sk); 1027 struct mptcp_data_frag *dtmp, *dfrag; 1028 bool cleaned = false; 1029 u64 snd_una; 1030 1031 /* on fallback we just need to ignore snd_una, as this is really 1032 * plain TCP 1033 */ 1034 if (__mptcp_check_fallback(msk)) 1035 msk->snd_una = READ_ONCE(msk->snd_nxt); 1036 1037 snd_una = msk->snd_una; 1038 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 1039 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 1040 break; 1041 1042 if (WARN_ON_ONCE(dfrag == msk->first_pending)) 1043 break; 1044 dfrag_clear(sk, dfrag); 1045 cleaned = true; 1046 } 1047 1048 dfrag = mptcp_rtx_head(sk); 1049 if (dfrag && after64(snd_una, dfrag->data_seq)) { 1050 u64 delta = snd_una - dfrag->data_seq; 1051 1052 if (WARN_ON_ONCE(delta > dfrag->already_sent)) 1053 goto out; 1054 1055 dfrag->data_seq += delta; 1056 dfrag->offset += delta; 1057 dfrag->data_len -= delta; 1058 dfrag->already_sent -= delta; 1059 1060 dfrag_uncharge(sk, delta); 1061 cleaned = true; 1062 } 1063 1064 out: 1065 if (cleaned) { 1066 if (tcp_under_memory_pressure(sk)) { 1067 __mptcp_update_wmem(sk); 1068 sk_mem_reclaim_partial(sk); 1069 } 1070 } 1071 1072 if (snd_una == READ_ONCE(msk->snd_nxt)) { 1073 if (msk->timer_ival && !mptcp_data_fin_enabled(msk)) 1074 mptcp_stop_timer(sk); 1075 } else { 1076 mptcp_reset_timer(sk); 1077 } 1078 } 1079 1080 static void __mptcp_clean_una_wakeup(struct sock *sk) 1081 { 1082 __mptcp_clean_una(sk); 1083 mptcp_write_space(sk); 1084 } 1085 1086 static void mptcp_enter_memory_pressure(struct sock *sk) 1087 { 1088 struct mptcp_subflow_context *subflow; 1089 struct mptcp_sock *msk = mptcp_sk(sk); 1090 bool first = true; 1091 1092 sk_stream_moderate_sndbuf(sk); 1093 mptcp_for_each_subflow(msk, subflow) { 1094 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1095 1096 if (first) 1097 tcp_enter_memory_pressure(ssk); 1098 sk_stream_moderate_sndbuf(ssk); 1099 first = false; 1100 } 1101 } 1102 1103 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 1104 * data 1105 */ 1106 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 1107 { 1108 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 1109 pfrag, sk->sk_allocation))) 1110 return true; 1111 1112 mptcp_enter_memory_pressure(sk); 1113 return false; 1114 } 1115 1116 static struct mptcp_data_frag * 1117 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 1118 int orig_offset) 1119 { 1120 int offset = ALIGN(orig_offset, sizeof(long)); 1121 struct mptcp_data_frag *dfrag; 1122 1123 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 1124 dfrag->data_len = 0; 1125 dfrag->data_seq = msk->write_seq; 1126 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 1127 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 1128 dfrag->already_sent = 0; 1129 dfrag->page = pfrag->page; 1130 1131 return dfrag; 1132 } 1133 1134 struct mptcp_sendmsg_info { 1135 int mss_now; 1136 int size_goal; 1137 u16 limit; 1138 u16 sent; 1139 unsigned int flags; 1140 }; 1141 1142 static int mptcp_check_allowed_size(struct mptcp_sock *msk, u64 data_seq, 1143 int avail_size) 1144 { 1145 u64 window_end = mptcp_wnd_end(msk); 1146 1147 if (__mptcp_check_fallback(msk)) 1148 return avail_size; 1149 1150 if (!before64(data_seq + avail_size, window_end)) { 1151 u64 allowed_size = window_end - data_seq; 1152 1153 return min_t(unsigned int, allowed_size, avail_size); 1154 } 1155 1156 return avail_size; 1157 } 1158 1159 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) 1160 { 1161 struct skb_ext *mpext = __skb_ext_alloc(gfp); 1162 1163 if (!mpext) 1164 return false; 1165 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); 1166 return true; 1167 } 1168 1169 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) 1170 { 1171 struct sk_buff *skb; 1172 1173 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); 1174 if (likely(skb)) { 1175 if (likely(__mptcp_add_ext(skb, gfp))) { 1176 skb_reserve(skb, MAX_TCP_HEADER); 1177 skb->reserved_tailroom = skb->end - skb->tail; 1178 return skb; 1179 } 1180 __kfree_skb(skb); 1181 } else { 1182 mptcp_enter_memory_pressure(sk); 1183 } 1184 return NULL; 1185 } 1186 1187 static bool mptcp_tx_cache_refill(struct sock *sk, int size, 1188 struct sk_buff_head *skbs, int *total_ts) 1189 { 1190 struct mptcp_sock *msk = mptcp_sk(sk); 1191 struct sk_buff *skb; 1192 int space_needed; 1193 1194 if (unlikely(tcp_under_memory_pressure(sk))) { 1195 mptcp_mem_reclaim_partial(sk); 1196 1197 /* under pressure pre-allocate at most a single skb */ 1198 if (msk->skb_tx_cache.qlen) 1199 return true; 1200 space_needed = msk->size_goal_cache; 1201 } else { 1202 space_needed = msk->tx_pending_data + size - 1203 msk->skb_tx_cache.qlen * msk->size_goal_cache; 1204 } 1205 1206 while (space_needed > 0) { 1207 skb = __mptcp_do_alloc_tx_skb(sk, sk->sk_allocation); 1208 if (unlikely(!skb)) { 1209 /* under memory pressure, try to pass the caller a 1210 * single skb to allow forward progress 1211 */ 1212 while (skbs->qlen > 1) { 1213 skb = __skb_dequeue_tail(skbs); 1214 *total_ts -= skb->truesize; 1215 __kfree_skb(skb); 1216 } 1217 return skbs->qlen > 0; 1218 } 1219 1220 *total_ts += skb->truesize; 1221 __skb_queue_tail(skbs, skb); 1222 space_needed -= msk->size_goal_cache; 1223 } 1224 return true; 1225 } 1226 1227 static bool __mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) 1228 { 1229 struct mptcp_sock *msk = mptcp_sk(sk); 1230 struct sk_buff *skb; 1231 1232 if (ssk->sk_tx_skb_cache) { 1233 skb = ssk->sk_tx_skb_cache; 1234 if (unlikely(!skb_ext_find(skb, SKB_EXT_MPTCP) && 1235 !__mptcp_add_ext(skb, gfp))) 1236 return false; 1237 return true; 1238 } 1239 1240 skb = skb_peek(&msk->skb_tx_cache); 1241 if (skb) { 1242 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1243 skb = __skb_dequeue(&msk->skb_tx_cache); 1244 if (WARN_ON_ONCE(!skb)) 1245 return false; 1246 1247 mptcp_wmem_uncharge(sk, skb->truesize); 1248 ssk->sk_tx_skb_cache = skb; 1249 return true; 1250 } 1251 1252 /* over memory limit, no point to try to allocate a new skb */ 1253 return false; 1254 } 1255 1256 skb = __mptcp_do_alloc_tx_skb(sk, gfp); 1257 if (!skb) 1258 return false; 1259 1260 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1261 ssk->sk_tx_skb_cache = skb; 1262 return true; 1263 } 1264 kfree_skb(skb); 1265 return false; 1266 } 1267 1268 static bool mptcp_must_reclaim_memory(struct sock *sk, struct sock *ssk) 1269 { 1270 return !ssk->sk_tx_skb_cache && 1271 !skb_peek(&mptcp_sk(sk)->skb_tx_cache) && 1272 tcp_under_memory_pressure(sk); 1273 } 1274 1275 static bool mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk) 1276 { 1277 if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) 1278 mptcp_mem_reclaim_partial(sk); 1279 return __mptcp_alloc_tx_skb(sk, ssk, sk->sk_allocation); 1280 } 1281 1282 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 1283 struct mptcp_data_frag *dfrag, 1284 struct mptcp_sendmsg_info *info) 1285 { 1286 u64 data_seq = dfrag->data_seq + info->sent; 1287 struct mptcp_sock *msk = mptcp_sk(sk); 1288 bool zero_window_probe = false; 1289 struct mptcp_ext *mpext = NULL; 1290 struct sk_buff *skb, *tail; 1291 bool can_collapse = false; 1292 int size_bias = 0; 1293 int avail_size; 1294 size_t ret = 0; 1295 1296 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", 1297 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); 1298 1299 /* compute send limit */ 1300 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); 1301 avail_size = info->size_goal; 1302 msk->size_goal_cache = info->size_goal; 1303 skb = tcp_write_queue_tail(ssk); 1304 if (skb) { 1305 /* Limit the write to the size available in the 1306 * current skb, if any, so that we create at most a new skb. 1307 * Explicitly tells TCP internals to avoid collapsing on later 1308 * queue management operation, to avoid breaking the ext <-> 1309 * SSN association set here 1310 */ 1311 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1312 can_collapse = (info->size_goal - skb->len > 0) && 1313 mptcp_skb_can_collapse_to(data_seq, skb, mpext); 1314 if (!can_collapse) { 1315 TCP_SKB_CB(skb)->eor = 1; 1316 } else { 1317 size_bias = skb->len; 1318 avail_size = info->size_goal - skb->len; 1319 } 1320 } 1321 1322 /* Zero window and all data acked? Probe. */ 1323 avail_size = mptcp_check_allowed_size(msk, data_seq, avail_size); 1324 if (avail_size == 0) { 1325 u64 snd_una = READ_ONCE(msk->snd_una); 1326 1327 if (skb || snd_una != msk->snd_nxt) 1328 return 0; 1329 zero_window_probe = true; 1330 data_seq = snd_una - 1; 1331 avail_size = 1; 1332 } 1333 1334 if (WARN_ON_ONCE(info->sent > info->limit || 1335 info->limit > dfrag->data_len)) 1336 return 0; 1337 1338 ret = info->limit - info->sent; 1339 tail = tcp_build_frag(ssk, avail_size + size_bias, info->flags, 1340 dfrag->page, dfrag->offset + info->sent, &ret); 1341 if (!tail) { 1342 tcp_remove_empty_skb(sk, tcp_write_queue_tail(ssk)); 1343 return -ENOMEM; 1344 } 1345 1346 /* if the tail skb is still the cached one, collapsing really happened. 1347 */ 1348 if (skb == tail) { 1349 TCP_SKB_CB(tail)->tcp_flags &= ~TCPHDR_PSH; 1350 mpext->data_len += ret; 1351 WARN_ON_ONCE(!can_collapse); 1352 WARN_ON_ONCE(zero_window_probe); 1353 goto out; 1354 } 1355 1356 mpext = skb_ext_find(tail, SKB_EXT_MPTCP); 1357 if (WARN_ON_ONCE(!mpext)) { 1358 /* should never reach here, stream corrupted */ 1359 return -EINVAL; 1360 } 1361 1362 memset(mpext, 0, sizeof(*mpext)); 1363 mpext->data_seq = data_seq; 1364 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 1365 mpext->data_len = ret; 1366 mpext->use_map = 1; 1367 mpext->dsn64 = 1; 1368 1369 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 1370 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 1371 mpext->dsn64); 1372 1373 if (zero_window_probe) { 1374 mptcp_subflow_ctx(ssk)->rel_write_seq += ret; 1375 mpext->frozen = 1; 1376 ret = 0; 1377 tcp_push_pending_frames(ssk); 1378 } 1379 out: 1380 mptcp_subflow_ctx(ssk)->rel_write_seq += ret; 1381 return ret; 1382 } 1383 1384 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ 1385 sizeof(struct tcphdr) - \ 1386 MAX_TCP_OPTION_SPACE - \ 1387 sizeof(struct ipv6hdr) - \ 1388 sizeof(struct frag_hdr)) 1389 1390 struct subflow_send_info { 1391 struct sock *ssk; 1392 u64 ratio; 1393 }; 1394 1395 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 1396 { 1397 struct subflow_send_info send_info[2]; 1398 struct mptcp_subflow_context *subflow; 1399 int i, nr_active = 0; 1400 struct sock *ssk; 1401 u64 ratio; 1402 u32 pace; 1403 1404 sock_owned_by_me((struct sock *)msk); 1405 1406 if (__mptcp_check_fallback(msk)) { 1407 if (!msk->first) 1408 return NULL; 1409 return sk_stream_memory_free(msk->first) ? msk->first : NULL; 1410 } 1411 1412 /* re-use last subflow, if the burst allow that */ 1413 if (msk->last_snd && msk->snd_burst > 0 && 1414 sk_stream_memory_free(msk->last_snd) && 1415 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) 1416 return msk->last_snd; 1417 1418 /* pick the subflow with the lower wmem/wspace ratio */ 1419 for (i = 0; i < 2; ++i) { 1420 send_info[i].ssk = NULL; 1421 send_info[i].ratio = -1; 1422 } 1423 mptcp_for_each_subflow(msk, subflow) { 1424 trace_mptcp_subflow_get_send(subflow); 1425 ssk = mptcp_subflow_tcp_sock(subflow); 1426 if (!mptcp_subflow_active(subflow)) 1427 continue; 1428 1429 nr_active += !subflow->backup; 1430 if (!sk_stream_memory_free(subflow->tcp_sock) || !tcp_sk(ssk)->snd_wnd) 1431 continue; 1432 1433 pace = READ_ONCE(ssk->sk_pacing_rate); 1434 if (!pace) 1435 continue; 1436 1437 ratio = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, 1438 pace); 1439 if (ratio < send_info[subflow->backup].ratio) { 1440 send_info[subflow->backup].ssk = ssk; 1441 send_info[subflow->backup].ratio = ratio; 1442 } 1443 } 1444 1445 /* pick the best backup if no other subflow is active */ 1446 if (!nr_active) 1447 send_info[0].ssk = send_info[1].ssk; 1448 1449 if (send_info[0].ssk) { 1450 msk->last_snd = send_info[0].ssk; 1451 msk->snd_burst = min_t(int, MPTCP_SEND_BURST_SIZE, 1452 tcp_sk(msk->last_snd)->snd_wnd); 1453 return msk->last_snd; 1454 } 1455 1456 return NULL; 1457 } 1458 1459 static void mptcp_push_release(struct sock *sk, struct sock *ssk, 1460 struct mptcp_sendmsg_info *info) 1461 { 1462 mptcp_set_timeout(sk, ssk); 1463 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); 1464 release_sock(ssk); 1465 } 1466 1467 static void __mptcp_push_pending(struct sock *sk, unsigned int flags) 1468 { 1469 struct sock *prev_ssk = NULL, *ssk = NULL; 1470 struct mptcp_sock *msk = mptcp_sk(sk); 1471 struct mptcp_sendmsg_info info = { 1472 .flags = flags, 1473 }; 1474 struct mptcp_data_frag *dfrag; 1475 int len, copied = 0; 1476 1477 while ((dfrag = mptcp_send_head(sk))) { 1478 info.sent = dfrag->already_sent; 1479 info.limit = dfrag->data_len; 1480 len = dfrag->data_len - dfrag->already_sent; 1481 while (len > 0) { 1482 int ret = 0; 1483 1484 prev_ssk = ssk; 1485 mptcp_flush_join_list(msk); 1486 ssk = mptcp_subflow_get_send(msk); 1487 1488 /* try to keep the subflow socket lock across 1489 * consecutive xmit on the same socket 1490 */ 1491 if (ssk != prev_ssk && prev_ssk) 1492 mptcp_push_release(sk, prev_ssk, &info); 1493 if (!ssk) 1494 goto out; 1495 1496 if (ssk != prev_ssk || !prev_ssk) 1497 lock_sock(ssk); 1498 1499 /* keep it simple and always provide a new skb for the 1500 * subflow, even if we will not use it when collapsing 1501 * on the pending one 1502 */ 1503 if (!mptcp_alloc_tx_skb(sk, ssk)) { 1504 mptcp_push_release(sk, ssk, &info); 1505 goto out; 1506 } 1507 1508 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1509 if (ret <= 0) { 1510 mptcp_push_release(sk, ssk, &info); 1511 goto out; 1512 } 1513 1514 info.sent += ret; 1515 dfrag->already_sent += ret; 1516 msk->snd_nxt += ret; 1517 msk->snd_burst -= ret; 1518 msk->tx_pending_data -= ret; 1519 copied += ret; 1520 len -= ret; 1521 } 1522 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1523 } 1524 1525 /* at this point we held the socket lock for the last subflow we used */ 1526 if (ssk) 1527 mptcp_push_release(sk, ssk, &info); 1528 1529 out: 1530 if (copied) { 1531 /* start the timer, if it's not pending */ 1532 if (!mptcp_timer_pending(sk)) 1533 mptcp_reset_timer(sk); 1534 __mptcp_check_send_data_fin(sk); 1535 } 1536 } 1537 1538 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk) 1539 { 1540 struct mptcp_sock *msk = mptcp_sk(sk); 1541 struct mptcp_sendmsg_info info; 1542 struct mptcp_data_frag *dfrag; 1543 struct sock *xmit_ssk; 1544 int len, copied = 0; 1545 bool first = true; 1546 1547 info.flags = 0; 1548 while ((dfrag = mptcp_send_head(sk))) { 1549 info.sent = dfrag->already_sent; 1550 info.limit = dfrag->data_len; 1551 len = dfrag->data_len - dfrag->already_sent; 1552 while (len > 0) { 1553 int ret = 0; 1554 1555 /* the caller already invoked the packet scheduler, 1556 * check for a different subflow usage only after 1557 * spooling the first chunk of data 1558 */ 1559 xmit_ssk = first ? ssk : mptcp_subflow_get_send(mptcp_sk(sk)); 1560 if (!xmit_ssk) 1561 goto out; 1562 if (xmit_ssk != ssk) { 1563 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk)); 1564 goto out; 1565 } 1566 1567 if (unlikely(mptcp_must_reclaim_memory(sk, ssk))) { 1568 __mptcp_update_wmem(sk); 1569 sk_mem_reclaim_partial(sk); 1570 } 1571 if (!__mptcp_alloc_tx_skb(sk, ssk, GFP_ATOMIC)) 1572 goto out; 1573 1574 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1575 if (ret <= 0) 1576 goto out; 1577 1578 info.sent += ret; 1579 dfrag->already_sent += ret; 1580 msk->snd_nxt += ret; 1581 msk->snd_burst -= ret; 1582 msk->tx_pending_data -= ret; 1583 copied += ret; 1584 len -= ret; 1585 first = false; 1586 } 1587 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1588 } 1589 1590 out: 1591 /* __mptcp_alloc_tx_skb could have released some wmem and we are 1592 * not going to flush it via release_sock() 1593 */ 1594 __mptcp_update_wmem(sk); 1595 if (copied) { 1596 mptcp_set_timeout(sk, ssk); 1597 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 1598 info.size_goal); 1599 if (!mptcp_timer_pending(sk)) 1600 mptcp_reset_timer(sk); 1601 1602 if (msk->snd_data_fin_enable && 1603 msk->snd_nxt + 1 == msk->write_seq) 1604 mptcp_schedule_work(sk); 1605 } 1606 } 1607 1608 static void mptcp_set_nospace(struct sock *sk) 1609 { 1610 /* enable autotune */ 1611 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1612 1613 /* will be cleared on avail space */ 1614 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); 1615 } 1616 1617 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1618 { 1619 struct mptcp_sock *msk = mptcp_sk(sk); 1620 struct page_frag *pfrag; 1621 size_t copied = 0; 1622 int ret = 0; 1623 long timeo; 1624 1625 /* we don't support FASTOPEN yet */ 1626 if (msg->msg_flags & MSG_FASTOPEN) 1627 return -EOPNOTSUPP; 1628 1629 /* silently ignore everything else */ 1630 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL; 1631 1632 mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, min_t(size_t, 1 << 20, len))); 1633 1634 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1635 1636 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 1637 ret = sk_stream_wait_connect(sk, &timeo); 1638 if (ret) 1639 goto out; 1640 } 1641 1642 pfrag = sk_page_frag(sk); 1643 1644 while (msg_data_left(msg)) { 1645 int total_ts, frag_truesize = 0; 1646 struct mptcp_data_frag *dfrag; 1647 struct sk_buff_head skbs; 1648 bool dfrag_collapsed; 1649 size_t psize, offset; 1650 1651 if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) { 1652 ret = -EPIPE; 1653 goto out; 1654 } 1655 1656 /* reuse tail pfrag, if possible, or carve a new one from the 1657 * page allocator 1658 */ 1659 dfrag = mptcp_pending_tail(sk); 1660 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 1661 if (!dfrag_collapsed) { 1662 if (!sk_stream_memory_free(sk)) 1663 goto wait_for_memory; 1664 1665 if (!mptcp_page_frag_refill(sk, pfrag)) 1666 goto wait_for_memory; 1667 1668 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); 1669 frag_truesize = dfrag->overhead; 1670 } 1671 1672 /* we do not bound vs wspace, to allow a single packet. 1673 * memory accounting will prevent execessive memory usage 1674 * anyway 1675 */ 1676 offset = dfrag->offset + dfrag->data_len; 1677 psize = pfrag->size - offset; 1678 psize = min_t(size_t, psize, msg_data_left(msg)); 1679 total_ts = psize + frag_truesize; 1680 __skb_queue_head_init(&skbs); 1681 if (!mptcp_tx_cache_refill(sk, psize, &skbs, &total_ts)) 1682 goto wait_for_memory; 1683 1684 if (!mptcp_wmem_alloc(sk, total_ts)) { 1685 __skb_queue_purge(&skbs); 1686 goto wait_for_memory; 1687 } 1688 1689 skb_queue_splice_tail(&skbs, &msk->skb_tx_cache); 1690 if (copy_page_from_iter(dfrag->page, offset, psize, 1691 &msg->msg_iter) != psize) { 1692 mptcp_wmem_uncharge(sk, psize + frag_truesize); 1693 ret = -EFAULT; 1694 goto out; 1695 } 1696 1697 /* data successfully copied into the write queue */ 1698 copied += psize; 1699 dfrag->data_len += psize; 1700 frag_truesize += psize; 1701 pfrag->offset += frag_truesize; 1702 WRITE_ONCE(msk->write_seq, msk->write_seq + psize); 1703 msk->tx_pending_data += psize; 1704 1705 /* charge data on mptcp pending queue to the msk socket 1706 * Note: we charge such data both to sk and ssk 1707 */ 1708 sk_wmem_queued_add(sk, frag_truesize); 1709 if (!dfrag_collapsed) { 1710 get_page(dfrag->page); 1711 list_add_tail(&dfrag->list, &msk->rtx_queue); 1712 if (!msk->first_pending) 1713 WRITE_ONCE(msk->first_pending, dfrag); 1714 } 1715 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, 1716 dfrag->data_seq, dfrag->data_len, dfrag->already_sent, 1717 !dfrag_collapsed); 1718 1719 continue; 1720 1721 wait_for_memory: 1722 mptcp_set_nospace(sk); 1723 __mptcp_push_pending(sk, msg->msg_flags); 1724 ret = sk_stream_wait_memory(sk, &timeo); 1725 if (ret) 1726 goto out; 1727 } 1728 1729 if (copied) 1730 __mptcp_push_pending(sk, msg->msg_flags); 1731 1732 out: 1733 release_sock(sk); 1734 return copied ? : ret; 1735 } 1736 1737 static void mptcp_wait_data(struct sock *sk, long *timeo) 1738 { 1739 DEFINE_WAIT_FUNC(wait, woken_wake_function); 1740 struct mptcp_sock *msk = mptcp_sk(sk); 1741 1742 add_wait_queue(sk_sleep(sk), &wait); 1743 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1744 1745 sk_wait_event(sk, timeo, 1746 test_and_clear_bit(MPTCP_DATA_READY, &msk->flags), &wait); 1747 1748 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 1749 remove_wait_queue(sk_sleep(sk), &wait); 1750 } 1751 1752 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1753 struct msghdr *msg, 1754 size_t len, int flags) 1755 { 1756 struct sk_buff *skb, *tmp; 1757 int copied = 0; 1758 1759 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { 1760 u32 offset = MPTCP_SKB_CB(skb)->offset; 1761 u32 data_len = skb->len - offset; 1762 u32 count = min_t(size_t, len - copied, data_len); 1763 int err; 1764 1765 if (!(flags & MSG_TRUNC)) { 1766 err = skb_copy_datagram_msg(skb, offset, msg, count); 1767 if (unlikely(err < 0)) { 1768 if (!copied) 1769 return err; 1770 break; 1771 } 1772 } 1773 1774 copied += count; 1775 1776 if (count < data_len) { 1777 if (!(flags & MSG_PEEK)) 1778 MPTCP_SKB_CB(skb)->offset += count; 1779 break; 1780 } 1781 1782 if (!(flags & MSG_PEEK)) { 1783 /* we will bulk release the skb memory later */ 1784 skb->destructor = NULL; 1785 msk->rmem_released += skb->truesize; 1786 __skb_unlink(skb, &msk->receive_queue); 1787 __kfree_skb(skb); 1788 } 1789 1790 if (copied >= len) 1791 break; 1792 } 1793 1794 return copied; 1795 } 1796 1797 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1798 * 1799 * Only difference: Use highest rtt estimate of the subflows in use. 1800 */ 1801 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1802 { 1803 struct mptcp_subflow_context *subflow; 1804 struct sock *sk = (struct sock *)msk; 1805 u32 time, advmss = 1; 1806 u64 rtt_us, mstamp; 1807 1808 sock_owned_by_me(sk); 1809 1810 if (copied <= 0) 1811 return; 1812 1813 msk->rcvq_space.copied += copied; 1814 1815 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1816 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1817 1818 rtt_us = msk->rcvq_space.rtt_us; 1819 if (rtt_us && time < (rtt_us >> 3)) 1820 return; 1821 1822 rtt_us = 0; 1823 mptcp_for_each_subflow(msk, subflow) { 1824 const struct tcp_sock *tp; 1825 u64 sf_rtt_us; 1826 u32 sf_advmss; 1827 1828 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1829 1830 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1831 sf_advmss = READ_ONCE(tp->advmss); 1832 1833 rtt_us = max(sf_rtt_us, rtt_us); 1834 advmss = max(sf_advmss, advmss); 1835 } 1836 1837 msk->rcvq_space.rtt_us = rtt_us; 1838 if (time < (rtt_us >> 3) || rtt_us == 0) 1839 return; 1840 1841 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 1842 goto new_measure; 1843 1844 if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && 1845 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 1846 int rcvmem, rcvbuf; 1847 u64 rcvwin, grow; 1848 1849 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 1850 1851 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 1852 1853 do_div(grow, msk->rcvq_space.space); 1854 rcvwin += (grow << 1); 1855 1856 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER); 1857 while (tcp_win_from_space(sk, rcvmem) < advmss) 1858 rcvmem += 128; 1859 1860 do_div(rcvwin, advmss); 1861 rcvbuf = min_t(u64, rcvwin * rcvmem, 1862 sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); 1863 1864 if (rcvbuf > sk->sk_rcvbuf) { 1865 u32 window_clamp; 1866 1867 window_clamp = tcp_win_from_space(sk, rcvbuf); 1868 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 1869 1870 /* Make subflows follow along. If we do not do this, we 1871 * get drops at subflow level if skbs can't be moved to 1872 * the mptcp rx queue fast enough (announced rcv_win can 1873 * exceed ssk->sk_rcvbuf). 1874 */ 1875 mptcp_for_each_subflow(msk, subflow) { 1876 struct sock *ssk; 1877 bool slow; 1878 1879 ssk = mptcp_subflow_tcp_sock(subflow); 1880 slow = lock_sock_fast(ssk); 1881 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 1882 tcp_sk(ssk)->window_clamp = window_clamp; 1883 tcp_cleanup_rbuf(ssk, 1); 1884 unlock_sock_fast(ssk, slow); 1885 } 1886 } 1887 } 1888 1889 msk->rcvq_space.space = msk->rcvq_space.copied; 1890 new_measure: 1891 msk->rcvq_space.copied = 0; 1892 msk->rcvq_space.time = mstamp; 1893 } 1894 1895 static void __mptcp_update_rmem(struct sock *sk) 1896 { 1897 struct mptcp_sock *msk = mptcp_sk(sk); 1898 1899 if (!msk->rmem_released) 1900 return; 1901 1902 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); 1903 sk_mem_uncharge(sk, msk->rmem_released); 1904 msk->rmem_released = 0; 1905 } 1906 1907 static void __mptcp_splice_receive_queue(struct sock *sk) 1908 { 1909 struct mptcp_sock *msk = mptcp_sk(sk); 1910 1911 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); 1912 } 1913 1914 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 1915 { 1916 struct sock *sk = (struct sock *)msk; 1917 unsigned int moved = 0; 1918 bool ret, done; 1919 1920 mptcp_flush_join_list(msk); 1921 do { 1922 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 1923 bool slowpath; 1924 1925 /* we can have data pending in the subflows only if the msk 1926 * receive buffer was full at subflow_data_ready() time, 1927 * that is an unlikely slow path. 1928 */ 1929 if (likely(!ssk)) 1930 break; 1931 1932 slowpath = lock_sock_fast(ssk); 1933 mptcp_data_lock(sk); 1934 __mptcp_update_rmem(sk); 1935 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 1936 mptcp_data_unlock(sk); 1937 tcp_cleanup_rbuf(ssk, moved); 1938 unlock_sock_fast(ssk, slowpath); 1939 } while (!done); 1940 1941 /* acquire the data lock only if some input data is pending */ 1942 ret = moved > 0; 1943 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || 1944 !skb_queue_empty_lockless(&sk->sk_receive_queue)) { 1945 mptcp_data_lock(sk); 1946 __mptcp_update_rmem(sk); 1947 ret |= __mptcp_ofo_queue(msk); 1948 __mptcp_splice_receive_queue(sk); 1949 mptcp_data_unlock(sk); 1950 mptcp_cleanup_rbuf(msk); 1951 } 1952 if (ret) 1953 mptcp_check_data_fin((struct sock *)msk); 1954 return !skb_queue_empty(&msk->receive_queue); 1955 } 1956 1957 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 1958 int nonblock, int flags, int *addr_len) 1959 { 1960 struct mptcp_sock *msk = mptcp_sk(sk); 1961 int copied = 0; 1962 int target; 1963 long timeo; 1964 1965 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ 1966 if (unlikely(flags & MSG_ERRQUEUE)) 1967 return inet_recv_error(sk, msg, len, addr_len); 1968 1969 mptcp_lock_sock(sk, __mptcp_splice_receive_queue(sk)); 1970 if (unlikely(sk->sk_state == TCP_LISTEN)) { 1971 copied = -ENOTCONN; 1972 goto out_err; 1973 } 1974 1975 timeo = sock_rcvtimeo(sk, nonblock); 1976 1977 len = min_t(size_t, len, INT_MAX); 1978 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 1979 1980 while (copied < len) { 1981 int bytes_read; 1982 1983 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags); 1984 if (unlikely(bytes_read < 0)) { 1985 if (!copied) 1986 copied = bytes_read; 1987 goto out_err; 1988 } 1989 1990 copied += bytes_read; 1991 1992 /* be sure to advertise window change */ 1993 mptcp_cleanup_rbuf(msk); 1994 1995 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) 1996 continue; 1997 1998 /* only the master socket status is relevant here. The exit 1999 * conditions mirror closely tcp_recvmsg() 2000 */ 2001 if (copied >= target) 2002 break; 2003 2004 if (copied) { 2005 if (sk->sk_err || 2006 sk->sk_state == TCP_CLOSE || 2007 (sk->sk_shutdown & RCV_SHUTDOWN) || 2008 !timeo || 2009 signal_pending(current)) 2010 break; 2011 } else { 2012 if (sk->sk_err) { 2013 copied = sock_error(sk); 2014 break; 2015 } 2016 2017 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2018 mptcp_check_for_eof(msk); 2019 2020 if (sk->sk_shutdown & RCV_SHUTDOWN) { 2021 /* race breaker: the shutdown could be after the 2022 * previous receive queue check 2023 */ 2024 if (__mptcp_move_skbs(msk)) 2025 continue; 2026 break; 2027 } 2028 2029 if (sk->sk_state == TCP_CLOSE) { 2030 copied = -ENOTCONN; 2031 break; 2032 } 2033 2034 if (!timeo) { 2035 copied = -EAGAIN; 2036 break; 2037 } 2038 2039 if (signal_pending(current)) { 2040 copied = sock_intr_errno(timeo); 2041 break; 2042 } 2043 } 2044 2045 pr_debug("block timeout %ld", timeo); 2046 mptcp_wait_data(sk, &timeo); 2047 } 2048 2049 if (skb_queue_empty_lockless(&sk->sk_receive_queue) && 2050 skb_queue_empty(&msk->receive_queue)) { 2051 /* entire backlog drained, clear DATA_READY. */ 2052 clear_bit(MPTCP_DATA_READY, &msk->flags); 2053 2054 /* .. race-breaker: ssk might have gotten new data 2055 * after last __mptcp_move_skbs() returned false. 2056 */ 2057 if (unlikely(__mptcp_move_skbs(msk))) 2058 set_bit(MPTCP_DATA_READY, &msk->flags); 2059 } else if (unlikely(!test_bit(MPTCP_DATA_READY, &msk->flags))) { 2060 /* data to read but mptcp_wait_data() cleared DATA_READY */ 2061 set_bit(MPTCP_DATA_READY, &msk->flags); 2062 } 2063 out_err: 2064 pr_debug("msk=%p data_ready=%d rx queue empty=%d copied=%d", 2065 msk, test_bit(MPTCP_DATA_READY, &msk->flags), 2066 skb_queue_empty_lockless(&sk->sk_receive_queue), copied); 2067 if (!(flags & MSG_PEEK)) 2068 mptcp_rcv_space_adjust(msk, copied); 2069 2070 release_sock(sk); 2071 return copied; 2072 } 2073 2074 static void mptcp_retransmit_timer(struct timer_list *t) 2075 { 2076 struct inet_connection_sock *icsk = from_timer(icsk, t, 2077 icsk_retransmit_timer); 2078 struct sock *sk = &icsk->icsk_inet.sk; 2079 struct mptcp_sock *msk = mptcp_sk(sk); 2080 2081 bh_lock_sock(sk); 2082 if (!sock_owned_by_user(sk)) { 2083 /* we need a process context to retransmit */ 2084 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) 2085 mptcp_schedule_work(sk); 2086 } else { 2087 /* delegate our work to tcp_release_cb() */ 2088 set_bit(MPTCP_RETRANSMIT, &msk->flags); 2089 } 2090 bh_unlock_sock(sk); 2091 sock_put(sk); 2092 } 2093 2094 static void mptcp_timeout_timer(struct timer_list *t) 2095 { 2096 struct sock *sk = from_timer(sk, t, sk_timer); 2097 2098 mptcp_schedule_work(sk); 2099 sock_put(sk); 2100 } 2101 2102 /* Find an idle subflow. Return NULL if there is unacked data at tcp 2103 * level. 2104 * 2105 * A backup subflow is returned only if that is the only kind available. 2106 */ 2107 static struct sock *mptcp_subflow_get_retrans(const struct mptcp_sock *msk) 2108 { 2109 struct mptcp_subflow_context *subflow; 2110 struct sock *backup = NULL; 2111 2112 sock_owned_by_me((const struct sock *)msk); 2113 2114 if (__mptcp_check_fallback(msk)) 2115 return NULL; 2116 2117 mptcp_for_each_subflow(msk, subflow) { 2118 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2119 2120 if (!mptcp_subflow_active(subflow)) 2121 continue; 2122 2123 /* still data outstanding at TCP level? Don't retransmit. */ 2124 if (!tcp_write_queue_empty(ssk)) { 2125 if (inet_csk(ssk)->icsk_ca_state >= TCP_CA_Loss) 2126 continue; 2127 return NULL; 2128 } 2129 2130 if (subflow->backup) { 2131 if (!backup) 2132 backup = ssk; 2133 continue; 2134 } 2135 2136 return ssk; 2137 } 2138 2139 return backup; 2140 } 2141 2142 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk) 2143 { 2144 if (msk->subflow) { 2145 iput(SOCK_INODE(msk->subflow)); 2146 msk->subflow = NULL; 2147 } 2148 } 2149 2150 /* subflow sockets can be either outgoing (connect) or incoming 2151 * (accept). 2152 * 2153 * Outgoing subflows use in-kernel sockets. 2154 * Incoming subflows do not have their own 'struct socket' allocated, 2155 * so we need to use tcp_close() after detaching them from the mptcp 2156 * parent socket. 2157 */ 2158 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2159 struct mptcp_subflow_context *subflow) 2160 { 2161 struct mptcp_sock *msk = mptcp_sk(sk); 2162 2163 list_del(&subflow->node); 2164 2165 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2166 2167 /* if we are invoked by the msk cleanup code, the subflow is 2168 * already orphaned 2169 */ 2170 if (ssk->sk_socket) 2171 sock_orphan(ssk); 2172 2173 subflow->disposable = 1; 2174 2175 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops 2176 * the ssk has been already destroyed, we just need to release the 2177 * reference owned by msk; 2178 */ 2179 if (!inet_csk(ssk)->icsk_ulp_ops) { 2180 kfree_rcu(subflow, rcu); 2181 } else { 2182 /* otherwise tcp will dispose of the ssk and subflow ctx */ 2183 __tcp_close(ssk, 0); 2184 2185 /* close acquired an extra ref */ 2186 __sock_put(ssk); 2187 } 2188 release_sock(ssk); 2189 2190 sock_put(ssk); 2191 2192 if (ssk == msk->last_snd) 2193 msk->last_snd = NULL; 2194 2195 if (ssk == msk->ack_hint) 2196 msk->ack_hint = NULL; 2197 2198 if (ssk == msk->first) 2199 msk->first = NULL; 2200 2201 if (msk->subflow && ssk == msk->subflow->sk) 2202 mptcp_dispose_initial_subflow(msk); 2203 } 2204 2205 void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2206 struct mptcp_subflow_context *subflow) 2207 { 2208 if (sk->sk_state == TCP_ESTABLISHED) 2209 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); 2210 __mptcp_close_ssk(sk, ssk, subflow); 2211 } 2212 2213 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 2214 { 2215 return 0; 2216 } 2217 2218 static void __mptcp_close_subflow(struct mptcp_sock *msk) 2219 { 2220 struct mptcp_subflow_context *subflow, *tmp; 2221 2222 might_sleep(); 2223 2224 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { 2225 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2226 2227 if (inet_sk_state_load(ssk) != TCP_CLOSE) 2228 continue; 2229 2230 /* 'subflow_data_ready' will re-sched once rx queue is empty */ 2231 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) 2232 continue; 2233 2234 mptcp_close_ssk((struct sock *)msk, ssk, subflow); 2235 } 2236 } 2237 2238 static bool mptcp_check_close_timeout(const struct sock *sk) 2239 { 2240 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp; 2241 struct mptcp_subflow_context *subflow; 2242 2243 if (delta >= TCP_TIMEWAIT_LEN) 2244 return true; 2245 2246 /* if all subflows are in closed status don't bother with additional 2247 * timeout 2248 */ 2249 mptcp_for_each_subflow(mptcp_sk(sk), subflow) { 2250 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) != 2251 TCP_CLOSE) 2252 return false; 2253 } 2254 return true; 2255 } 2256 2257 static void mptcp_check_fastclose(struct mptcp_sock *msk) 2258 { 2259 struct mptcp_subflow_context *subflow, *tmp; 2260 struct sock *sk = &msk->sk.icsk_inet.sk; 2261 2262 if (likely(!READ_ONCE(msk->rcv_fastclose))) 2263 return; 2264 2265 mptcp_token_destroy(msk); 2266 2267 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) { 2268 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2269 2270 lock_sock(tcp_sk); 2271 if (tcp_sk->sk_state != TCP_CLOSE) { 2272 tcp_send_active_reset(tcp_sk, GFP_ATOMIC); 2273 tcp_set_state(tcp_sk, TCP_CLOSE); 2274 } 2275 release_sock(tcp_sk); 2276 } 2277 2278 inet_sk_state_store(sk, TCP_CLOSE); 2279 sk->sk_shutdown = SHUTDOWN_MASK; 2280 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 2281 set_bit(MPTCP_DATA_READY, &msk->flags); 2282 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); 2283 2284 mptcp_close_wake_up(sk); 2285 } 2286 2287 static void __mptcp_retrans(struct sock *sk) 2288 { 2289 struct mptcp_sock *msk = mptcp_sk(sk); 2290 struct mptcp_sendmsg_info info = {}; 2291 struct mptcp_data_frag *dfrag; 2292 size_t copied = 0; 2293 struct sock *ssk; 2294 int ret; 2295 2296 __mptcp_clean_una_wakeup(sk); 2297 dfrag = mptcp_rtx_head(sk); 2298 if (!dfrag) { 2299 if (mptcp_data_fin_enabled(msk)) { 2300 struct inet_connection_sock *icsk = inet_csk(sk); 2301 2302 icsk->icsk_retransmits++; 2303 mptcp_set_datafin_timeout(sk); 2304 mptcp_send_ack(msk); 2305 2306 goto reset_timer; 2307 } 2308 2309 return; 2310 } 2311 2312 ssk = mptcp_subflow_get_retrans(msk); 2313 if (!ssk) 2314 goto reset_timer; 2315 2316 lock_sock(ssk); 2317 2318 /* limit retransmission to the bytes already sent on some subflows */ 2319 info.sent = 0; 2320 info.limit = dfrag->already_sent; 2321 while (info.sent < dfrag->already_sent) { 2322 if (!mptcp_alloc_tx_skb(sk, ssk)) 2323 break; 2324 2325 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 2326 if (ret <= 0) 2327 break; 2328 2329 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 2330 copied += ret; 2331 info.sent += ret; 2332 } 2333 if (copied) 2334 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 2335 info.size_goal); 2336 2337 mptcp_set_timeout(sk, ssk); 2338 release_sock(ssk); 2339 2340 reset_timer: 2341 if (!mptcp_timer_pending(sk)) 2342 mptcp_reset_timer(sk); 2343 } 2344 2345 static void mptcp_worker(struct work_struct *work) 2346 { 2347 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 2348 struct sock *sk = &msk->sk.icsk_inet.sk; 2349 int state; 2350 2351 lock_sock(sk); 2352 state = sk->sk_state; 2353 if (unlikely(state == TCP_CLOSE)) 2354 goto unlock; 2355 2356 mptcp_check_data_fin_ack(sk); 2357 mptcp_flush_join_list(msk); 2358 2359 mptcp_check_fastclose(msk); 2360 2361 if (msk->pm.status) 2362 mptcp_pm_nl_work(msk); 2363 2364 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2365 mptcp_check_for_eof(msk); 2366 2367 __mptcp_check_send_data_fin(sk); 2368 mptcp_check_data_fin(sk); 2369 2370 /* There is no point in keeping around an orphaned sk timedout or 2371 * closed, but we need the msk around to reply to incoming DATA_FIN, 2372 * even if it is orphaned and in FIN_WAIT2 state 2373 */ 2374 if (sock_flag(sk, SOCK_DEAD) && 2375 (mptcp_check_close_timeout(sk) || sk->sk_state == TCP_CLOSE)) { 2376 inet_sk_state_store(sk, TCP_CLOSE); 2377 __mptcp_destroy_sock(sk); 2378 goto unlock; 2379 } 2380 2381 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) 2382 __mptcp_close_subflow(msk); 2383 2384 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 2385 __mptcp_retrans(sk); 2386 2387 unlock: 2388 release_sock(sk); 2389 sock_put(sk); 2390 } 2391 2392 static int __mptcp_init_sock(struct sock *sk) 2393 { 2394 struct mptcp_sock *msk = mptcp_sk(sk); 2395 2396 spin_lock_init(&msk->join_list_lock); 2397 2398 INIT_LIST_HEAD(&msk->conn_list); 2399 INIT_LIST_HEAD(&msk->join_list); 2400 INIT_LIST_HEAD(&msk->rtx_queue); 2401 INIT_WORK(&msk->work, mptcp_worker); 2402 __skb_queue_head_init(&msk->receive_queue); 2403 __skb_queue_head_init(&msk->skb_tx_cache); 2404 msk->out_of_order_queue = RB_ROOT; 2405 msk->first_pending = NULL; 2406 msk->wmem_reserved = 0; 2407 msk->rmem_released = 0; 2408 msk->tx_pending_data = 0; 2409 msk->size_goal_cache = TCP_BASE_MSS; 2410 2411 msk->ack_hint = NULL; 2412 msk->first = NULL; 2413 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 2414 2415 mptcp_pm_data_init(msk); 2416 2417 /* re-use the csk retrans timer for MPTCP-level retrans */ 2418 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 2419 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0); 2420 2421 tcp_assign_congestion_control(sk); 2422 2423 return 0; 2424 } 2425 2426 static int mptcp_init_sock(struct sock *sk) 2427 { 2428 struct net *net = sock_net(sk); 2429 int ret; 2430 2431 ret = __mptcp_init_sock(sk); 2432 if (ret) 2433 return ret; 2434 2435 if (!mptcp_is_enabled(net)) 2436 return -ENOPROTOOPT; 2437 2438 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 2439 return -ENOMEM; 2440 2441 ret = __mptcp_socket_create(mptcp_sk(sk)); 2442 if (ret) 2443 return ret; 2444 2445 sk_sockets_allocated_inc(sk); 2446 sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1]; 2447 sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1]; 2448 2449 return 0; 2450 } 2451 2452 static void __mptcp_clear_xmit(struct sock *sk) 2453 { 2454 struct mptcp_sock *msk = mptcp_sk(sk); 2455 struct mptcp_data_frag *dtmp, *dfrag; 2456 struct sk_buff *skb; 2457 2458 WRITE_ONCE(msk->first_pending, NULL); 2459 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 2460 dfrag_clear(sk, dfrag); 2461 while ((skb = __skb_dequeue(&msk->skb_tx_cache)) != NULL) { 2462 sk->sk_forward_alloc += skb->truesize; 2463 kfree_skb(skb); 2464 } 2465 } 2466 2467 static void mptcp_cancel_work(struct sock *sk) 2468 { 2469 struct mptcp_sock *msk = mptcp_sk(sk); 2470 2471 if (cancel_work_sync(&msk->work)) 2472 __sock_put(sk); 2473 } 2474 2475 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 2476 { 2477 lock_sock(ssk); 2478 2479 switch (ssk->sk_state) { 2480 case TCP_LISTEN: 2481 if (!(how & RCV_SHUTDOWN)) 2482 break; 2483 fallthrough; 2484 case TCP_SYN_SENT: 2485 tcp_disconnect(ssk, O_NONBLOCK); 2486 break; 2487 default: 2488 if (__mptcp_check_fallback(mptcp_sk(sk))) { 2489 pr_debug("Fallback"); 2490 ssk->sk_shutdown |= how; 2491 tcp_shutdown(ssk, how); 2492 } else { 2493 pr_debug("Sending DATA_FIN on subflow %p", ssk); 2494 mptcp_set_timeout(sk, ssk); 2495 tcp_send_ack(ssk); 2496 if (!mptcp_timer_pending(sk)) 2497 mptcp_reset_timer(sk); 2498 } 2499 break; 2500 } 2501 2502 release_sock(ssk); 2503 } 2504 2505 static const unsigned char new_state[16] = { 2506 /* current state: new state: action: */ 2507 [0 /* (Invalid) */] = TCP_CLOSE, 2508 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2509 [TCP_SYN_SENT] = TCP_CLOSE, 2510 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2511 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 2512 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 2513 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 2514 [TCP_CLOSE] = TCP_CLOSE, 2515 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 2516 [TCP_LAST_ACK] = TCP_LAST_ACK, 2517 [TCP_LISTEN] = TCP_CLOSE, 2518 [TCP_CLOSING] = TCP_CLOSING, 2519 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 2520 }; 2521 2522 static int mptcp_close_state(struct sock *sk) 2523 { 2524 int next = (int)new_state[sk->sk_state]; 2525 int ns = next & TCP_STATE_MASK; 2526 2527 inet_sk_state_store(sk, ns); 2528 2529 return next & TCP_ACTION_FIN; 2530 } 2531 2532 static void __mptcp_check_send_data_fin(struct sock *sk) 2533 { 2534 struct mptcp_subflow_context *subflow; 2535 struct mptcp_sock *msk = mptcp_sk(sk); 2536 2537 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", 2538 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), 2539 msk->snd_nxt, msk->write_seq); 2540 2541 /* we still need to enqueue subflows or not really shutting down, 2542 * skip this 2543 */ 2544 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || 2545 mptcp_send_head(sk)) 2546 return; 2547 2548 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2549 2550 /* fallback socket will not get data_fin/ack, can move to the next 2551 * state now 2552 */ 2553 if (__mptcp_check_fallback(msk)) { 2554 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) { 2555 inet_sk_state_store(sk, TCP_CLOSE); 2556 mptcp_close_wake_up(sk); 2557 } else if (sk->sk_state == TCP_FIN_WAIT1) { 2558 inet_sk_state_store(sk, TCP_FIN_WAIT2); 2559 } 2560 } 2561 2562 mptcp_flush_join_list(msk); 2563 mptcp_for_each_subflow(msk, subflow) { 2564 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2565 2566 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); 2567 } 2568 } 2569 2570 static void __mptcp_wr_shutdown(struct sock *sk) 2571 { 2572 struct mptcp_sock *msk = mptcp_sk(sk); 2573 2574 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", 2575 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, 2576 !!mptcp_send_head(sk)); 2577 2578 /* will be ignored by fallback sockets */ 2579 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2580 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2581 2582 __mptcp_check_send_data_fin(sk); 2583 } 2584 2585 static void __mptcp_destroy_sock(struct sock *sk) 2586 { 2587 struct mptcp_subflow_context *subflow, *tmp; 2588 struct mptcp_sock *msk = mptcp_sk(sk); 2589 LIST_HEAD(conn_list); 2590 2591 pr_debug("msk=%p", msk); 2592 2593 might_sleep(); 2594 2595 /* be sure to always acquire the join list lock, to sync vs 2596 * mptcp_finish_join(). 2597 */ 2598 spin_lock_bh(&msk->join_list_lock); 2599 list_splice_tail_init(&msk->join_list, &msk->conn_list); 2600 spin_unlock_bh(&msk->join_list_lock); 2601 list_splice_init(&msk->conn_list, &conn_list); 2602 2603 sk_stop_timer(sk, &msk->sk.icsk_retransmit_timer); 2604 sk_stop_timer(sk, &sk->sk_timer); 2605 msk->pm.status = 0; 2606 2607 list_for_each_entry_safe(subflow, tmp, &conn_list, node) { 2608 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2609 __mptcp_close_ssk(sk, ssk, subflow); 2610 } 2611 2612 sk->sk_prot->destroy(sk); 2613 2614 WARN_ON_ONCE(msk->wmem_reserved); 2615 WARN_ON_ONCE(msk->rmem_released); 2616 sk_stream_kill_queues(sk); 2617 xfrm_sk_free_policy(sk); 2618 2619 tcp_cleanup_congestion_control(sk); 2620 sk_refcnt_debug_release(sk); 2621 mptcp_dispose_initial_subflow(msk); 2622 sock_put(sk); 2623 } 2624 2625 static void mptcp_close(struct sock *sk, long timeout) 2626 { 2627 struct mptcp_subflow_context *subflow; 2628 bool do_cancel_work = false; 2629 2630 lock_sock(sk); 2631 sk->sk_shutdown = SHUTDOWN_MASK; 2632 2633 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { 2634 inet_sk_state_store(sk, TCP_CLOSE); 2635 goto cleanup; 2636 } 2637 2638 if (mptcp_close_state(sk)) 2639 __mptcp_wr_shutdown(sk); 2640 2641 sk_stream_wait_close(sk, timeout); 2642 2643 cleanup: 2644 /* orphan all the subflows */ 2645 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32; 2646 mptcp_for_each_subflow(mptcp_sk(sk), subflow) { 2647 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2648 bool slow = lock_sock_fast(ssk); 2649 2650 sock_orphan(ssk); 2651 unlock_sock_fast(ssk, slow); 2652 } 2653 sock_orphan(sk); 2654 2655 sock_hold(sk); 2656 pr_debug("msk=%p state=%d", sk, sk->sk_state); 2657 if (sk->sk_state == TCP_CLOSE) { 2658 __mptcp_destroy_sock(sk); 2659 do_cancel_work = true; 2660 } else { 2661 sk_reset_timer(sk, &sk->sk_timer, jiffies + TCP_TIMEWAIT_LEN); 2662 } 2663 release_sock(sk); 2664 if (do_cancel_work) 2665 mptcp_cancel_work(sk); 2666 2667 if (mptcp_sk(sk)->token) 2668 mptcp_event(MPTCP_EVENT_CLOSED, mptcp_sk(sk), NULL, GFP_KERNEL); 2669 2670 sock_put(sk); 2671 } 2672 2673 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 2674 { 2675 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2676 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 2677 struct ipv6_pinfo *msk6 = inet6_sk(msk); 2678 2679 msk->sk_v6_daddr = ssk->sk_v6_daddr; 2680 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 2681 2682 if (msk6 && ssk6) { 2683 msk6->saddr = ssk6->saddr; 2684 msk6->flow_label = ssk6->flow_label; 2685 } 2686 #endif 2687 2688 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 2689 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 2690 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 2691 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 2692 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 2693 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 2694 } 2695 2696 static int mptcp_disconnect(struct sock *sk, int flags) 2697 { 2698 struct mptcp_subflow_context *subflow; 2699 struct mptcp_sock *msk = mptcp_sk(sk); 2700 2701 mptcp_do_flush_join_list(msk); 2702 2703 mptcp_for_each_subflow(msk, subflow) { 2704 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2705 2706 lock_sock(ssk); 2707 tcp_disconnect(ssk, flags); 2708 release_sock(ssk); 2709 } 2710 return 0; 2711 } 2712 2713 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2714 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 2715 { 2716 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 2717 2718 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 2719 } 2720 #endif 2721 2722 struct sock *mptcp_sk_clone(const struct sock *sk, 2723 const struct mptcp_options_received *mp_opt, 2724 struct request_sock *req) 2725 { 2726 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 2727 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 2728 struct mptcp_sock *msk; 2729 u64 ack_seq; 2730 2731 if (!nsk) 2732 return NULL; 2733 2734 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2735 if (nsk->sk_family == AF_INET6) 2736 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 2737 #endif 2738 2739 __mptcp_init_sock(nsk); 2740 2741 msk = mptcp_sk(nsk); 2742 msk->local_key = subflow_req->local_key; 2743 msk->token = subflow_req->token; 2744 msk->subflow = NULL; 2745 WRITE_ONCE(msk->fully_established, false); 2746 2747 msk->write_seq = subflow_req->idsn + 1; 2748 msk->snd_nxt = msk->write_seq; 2749 msk->snd_una = msk->write_seq; 2750 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; 2751 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; 2752 2753 if (mp_opt->mp_capable) { 2754 msk->can_ack = true; 2755 msk->remote_key = mp_opt->sndr_key; 2756 mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq); 2757 ack_seq++; 2758 WRITE_ONCE(msk->ack_seq, ack_seq); 2759 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 2760 } 2761 2762 sock_reset_flag(nsk, SOCK_RCU_FREE); 2763 /* will be fully established after successful MPC subflow creation */ 2764 inet_sk_state_store(nsk, TCP_SYN_RECV); 2765 2766 security_inet_csk_clone(nsk, req); 2767 bh_unlock_sock(nsk); 2768 2769 /* keep a single reference */ 2770 __sock_put(nsk); 2771 return nsk; 2772 } 2773 2774 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 2775 { 2776 const struct tcp_sock *tp = tcp_sk(ssk); 2777 2778 msk->rcvq_space.copied = 0; 2779 msk->rcvq_space.rtt_us = 0; 2780 2781 msk->rcvq_space.time = tp->tcp_mstamp; 2782 2783 /* initial rcv_space offering made to peer */ 2784 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 2785 TCP_INIT_CWND * tp->advmss); 2786 if (msk->rcvq_space.space == 0) 2787 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 2788 2789 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); 2790 } 2791 2792 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 2793 bool kern) 2794 { 2795 struct mptcp_sock *msk = mptcp_sk(sk); 2796 struct socket *listener; 2797 struct sock *newsk; 2798 2799 listener = __mptcp_nmpc_socket(msk); 2800 if (WARN_ON_ONCE(!listener)) { 2801 *err = -EINVAL; 2802 return NULL; 2803 } 2804 2805 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); 2806 newsk = inet_csk_accept(listener->sk, flags, err, kern); 2807 if (!newsk) 2808 return NULL; 2809 2810 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); 2811 if (sk_is_mptcp(newsk)) { 2812 struct mptcp_subflow_context *subflow; 2813 struct sock *new_mptcp_sock; 2814 2815 subflow = mptcp_subflow_ctx(newsk); 2816 new_mptcp_sock = subflow->conn; 2817 2818 /* is_mptcp should be false if subflow->conn is missing, see 2819 * subflow_syn_recv_sock() 2820 */ 2821 if (WARN_ON_ONCE(!new_mptcp_sock)) { 2822 tcp_sk(newsk)->is_mptcp = 0; 2823 return newsk; 2824 } 2825 2826 /* acquire the 2nd reference for the owning socket */ 2827 sock_hold(new_mptcp_sock); 2828 newsk = new_mptcp_sock; 2829 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 2830 } else { 2831 MPTCP_INC_STATS(sock_net(sk), 2832 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 2833 } 2834 2835 return newsk; 2836 } 2837 2838 void mptcp_destroy_common(struct mptcp_sock *msk) 2839 { 2840 struct sock *sk = (struct sock *)msk; 2841 2842 __mptcp_clear_xmit(sk); 2843 2844 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ 2845 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); 2846 2847 skb_rbtree_purge(&msk->out_of_order_queue); 2848 mptcp_token_destroy(msk); 2849 mptcp_pm_free_anno_list(msk); 2850 } 2851 2852 static void mptcp_destroy(struct sock *sk) 2853 { 2854 struct mptcp_sock *msk = mptcp_sk(sk); 2855 2856 mptcp_destroy_common(msk); 2857 sk_sockets_allocated_dec(sk); 2858 } 2859 2860 void __mptcp_data_acked(struct sock *sk) 2861 { 2862 if (!sock_owned_by_user(sk)) 2863 __mptcp_clean_una(sk); 2864 else 2865 set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags); 2866 2867 if (mptcp_pending_data_fin_ack(sk)) 2868 mptcp_schedule_work(sk); 2869 } 2870 2871 void __mptcp_check_push(struct sock *sk, struct sock *ssk) 2872 { 2873 if (!mptcp_send_head(sk)) 2874 return; 2875 2876 if (!sock_owned_by_user(sk)) { 2877 struct sock *xmit_ssk = mptcp_subflow_get_send(mptcp_sk(sk)); 2878 2879 if (xmit_ssk == ssk) 2880 __mptcp_subflow_push_pending(sk, ssk); 2881 else if (xmit_ssk) 2882 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk)); 2883 } else { 2884 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); 2885 } 2886 } 2887 2888 /* processes deferred events and flush wmem */ 2889 static void mptcp_release_cb(struct sock *sk) 2890 { 2891 for (;;) { 2892 unsigned long flags = 0; 2893 2894 if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) 2895 flags |= BIT(MPTCP_PUSH_PENDING); 2896 if (test_and_clear_bit(MPTCP_RETRANSMIT, &mptcp_sk(sk)->flags)) 2897 flags |= BIT(MPTCP_RETRANSMIT); 2898 if (!flags) 2899 break; 2900 2901 /* the following actions acquire the subflow socket lock 2902 * 2903 * 1) can't be invoked in atomic scope 2904 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX 2905 * datapath acquires the msk socket spinlock while helding 2906 * the subflow socket lock 2907 */ 2908 2909 spin_unlock_bh(&sk->sk_lock.slock); 2910 if (flags & BIT(MPTCP_PUSH_PENDING)) 2911 __mptcp_push_pending(sk, 0); 2912 if (flags & BIT(MPTCP_RETRANSMIT)) 2913 __mptcp_retrans(sk); 2914 2915 cond_resched(); 2916 spin_lock_bh(&sk->sk_lock.slock); 2917 } 2918 2919 if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) 2920 __mptcp_clean_una_wakeup(sk); 2921 if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags)) 2922 __mptcp_error_report(sk); 2923 2924 /* push_pending may touch wmem_reserved, ensure we do the cleanup 2925 * later 2926 */ 2927 __mptcp_update_wmem(sk); 2928 __mptcp_update_rmem(sk); 2929 } 2930 2931 void mptcp_subflow_process_delegated(struct sock *ssk) 2932 { 2933 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 2934 struct sock *sk = subflow->conn; 2935 2936 mptcp_data_lock(sk); 2937 if (!sock_owned_by_user(sk)) 2938 __mptcp_subflow_push_pending(sk, ssk); 2939 else 2940 set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags); 2941 mptcp_data_unlock(sk); 2942 mptcp_subflow_delegated_done(subflow); 2943 } 2944 2945 static int mptcp_hash(struct sock *sk) 2946 { 2947 /* should never be called, 2948 * we hash the TCP subflows not the master socket 2949 */ 2950 WARN_ON_ONCE(1); 2951 return 0; 2952 } 2953 2954 static void mptcp_unhash(struct sock *sk) 2955 { 2956 /* called from sk_common_release(), but nothing to do here */ 2957 } 2958 2959 static int mptcp_get_port(struct sock *sk, unsigned short snum) 2960 { 2961 struct mptcp_sock *msk = mptcp_sk(sk); 2962 struct socket *ssock; 2963 2964 ssock = __mptcp_nmpc_socket(msk); 2965 pr_debug("msk=%p, subflow=%p", msk, ssock); 2966 if (WARN_ON_ONCE(!ssock)) 2967 return -EINVAL; 2968 2969 return inet_csk_get_port(ssock->sk, snum); 2970 } 2971 2972 void mptcp_finish_connect(struct sock *ssk) 2973 { 2974 struct mptcp_subflow_context *subflow; 2975 struct mptcp_sock *msk; 2976 struct sock *sk; 2977 u64 ack_seq; 2978 2979 subflow = mptcp_subflow_ctx(ssk); 2980 sk = subflow->conn; 2981 msk = mptcp_sk(sk); 2982 2983 pr_debug("msk=%p, token=%u", sk, subflow->token); 2984 2985 mptcp_crypto_key_sha(subflow->remote_key, NULL, &ack_seq); 2986 ack_seq++; 2987 subflow->map_seq = ack_seq; 2988 subflow->map_subflow_seq = 1; 2989 2990 /* the socket is not connected yet, no msk/subflow ops can access/race 2991 * accessing the field below 2992 */ 2993 WRITE_ONCE(msk->remote_key, subflow->remote_key); 2994 WRITE_ONCE(msk->local_key, subflow->local_key); 2995 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 2996 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2997 WRITE_ONCE(msk->ack_seq, ack_seq); 2998 WRITE_ONCE(msk->rcv_wnd_sent, ack_seq); 2999 WRITE_ONCE(msk->can_ack, 1); 3000 WRITE_ONCE(msk->snd_una, msk->write_seq); 3001 3002 mptcp_pm_new_connection(msk, ssk, 0); 3003 3004 mptcp_rcv_space_init(msk, ssk); 3005 } 3006 3007 void mptcp_sock_graft(struct sock *sk, struct socket *parent) 3008 { 3009 write_lock_bh(&sk->sk_callback_lock); 3010 rcu_assign_pointer(sk->sk_wq, &parent->wq); 3011 sk_set_socket(sk, parent); 3012 sk->sk_uid = SOCK_INODE(parent)->i_uid; 3013 write_unlock_bh(&sk->sk_callback_lock); 3014 } 3015 3016 bool mptcp_finish_join(struct sock *ssk) 3017 { 3018 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3019 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 3020 struct sock *parent = (void *)msk; 3021 struct socket *parent_sock; 3022 bool ret; 3023 3024 pr_debug("msk=%p, subflow=%p", msk, subflow); 3025 3026 /* mptcp socket already closing? */ 3027 if (!mptcp_is_fully_established(parent)) { 3028 subflow->reset_reason = MPTCP_RST_EMPTCP; 3029 return false; 3030 } 3031 3032 if (!msk->pm.server_side) 3033 goto out; 3034 3035 if (!mptcp_pm_allow_new_subflow(msk)) { 3036 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3037 return false; 3038 } 3039 3040 /* active connections are already on conn_list, and we can't acquire 3041 * msk lock here. 3042 * use the join list lock as synchronization point and double-check 3043 * msk status to avoid racing with __mptcp_destroy_sock() 3044 */ 3045 spin_lock_bh(&msk->join_list_lock); 3046 ret = inet_sk_state_load(parent) == TCP_ESTABLISHED; 3047 if (ret && !WARN_ON_ONCE(!list_empty(&subflow->node))) { 3048 list_add_tail(&subflow->node, &msk->join_list); 3049 sock_hold(ssk); 3050 } 3051 spin_unlock_bh(&msk->join_list_lock); 3052 if (!ret) { 3053 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3054 return false; 3055 } 3056 3057 /* attach to msk socket only after we are sure he will deal with us 3058 * at close time 3059 */ 3060 parent_sock = READ_ONCE(parent->sk_socket); 3061 if (parent_sock && !ssk->sk_socket) 3062 mptcp_sock_graft(ssk, parent_sock); 3063 subflow->map_seq = READ_ONCE(msk->ack_seq); 3064 out: 3065 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); 3066 return true; 3067 } 3068 3069 static void mptcp_shutdown(struct sock *sk, int how) 3070 { 3071 pr_debug("sk=%p, how=%d", sk, how); 3072 3073 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) 3074 __mptcp_wr_shutdown(sk); 3075 } 3076 3077 static struct proto mptcp_prot = { 3078 .name = "MPTCP", 3079 .owner = THIS_MODULE, 3080 .init = mptcp_init_sock, 3081 .disconnect = mptcp_disconnect, 3082 .close = mptcp_close, 3083 .accept = mptcp_accept, 3084 .setsockopt = mptcp_setsockopt, 3085 .getsockopt = mptcp_getsockopt, 3086 .shutdown = mptcp_shutdown, 3087 .destroy = mptcp_destroy, 3088 .sendmsg = mptcp_sendmsg, 3089 .recvmsg = mptcp_recvmsg, 3090 .release_cb = mptcp_release_cb, 3091 .hash = mptcp_hash, 3092 .unhash = mptcp_unhash, 3093 .get_port = mptcp_get_port, 3094 .sockets_allocated = &mptcp_sockets_allocated, 3095 .memory_allocated = &tcp_memory_allocated, 3096 .memory_pressure = &tcp_memory_pressure, 3097 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3098 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3099 .sysctl_mem = sysctl_tcp_mem, 3100 .obj_size = sizeof(struct mptcp_sock), 3101 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3102 .no_autobind = true, 3103 }; 3104 3105 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 3106 { 3107 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3108 struct socket *ssock; 3109 int err; 3110 3111 lock_sock(sock->sk); 3112 ssock = __mptcp_nmpc_socket(msk); 3113 if (!ssock) { 3114 err = -EINVAL; 3115 goto unlock; 3116 } 3117 3118 err = ssock->ops->bind(ssock, uaddr, addr_len); 3119 if (!err) 3120 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3121 3122 unlock: 3123 release_sock(sock->sk); 3124 return err; 3125 } 3126 3127 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 3128 struct mptcp_subflow_context *subflow) 3129 { 3130 subflow->request_mptcp = 0; 3131 __mptcp_do_fallback(msk); 3132 } 3133 3134 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, 3135 int addr_len, int flags) 3136 { 3137 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3138 struct mptcp_subflow_context *subflow; 3139 struct socket *ssock; 3140 int err; 3141 3142 lock_sock(sock->sk); 3143 if (sock->state != SS_UNCONNECTED && msk->subflow) { 3144 /* pending connection or invalid state, let existing subflow 3145 * cope with that 3146 */ 3147 ssock = msk->subflow; 3148 goto do_connect; 3149 } 3150 3151 ssock = __mptcp_nmpc_socket(msk); 3152 if (!ssock) { 3153 err = -EINVAL; 3154 goto unlock; 3155 } 3156 3157 mptcp_token_destroy(msk); 3158 inet_sk_state_store(sock->sk, TCP_SYN_SENT); 3159 subflow = mptcp_subflow_ctx(ssock->sk); 3160 #ifdef CONFIG_TCP_MD5SIG 3161 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 3162 * TCP option space. 3163 */ 3164 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info)) 3165 mptcp_subflow_early_fallback(msk, subflow); 3166 #endif 3167 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) { 3168 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT); 3169 mptcp_subflow_early_fallback(msk, subflow); 3170 } 3171 if (likely(!__mptcp_check_fallback(msk))) 3172 MPTCP_INC_STATS(sock_net(sock->sk), MPTCP_MIB_MPCAPABLEACTIVE); 3173 3174 do_connect: 3175 err = ssock->ops->connect(ssock, uaddr, addr_len, flags); 3176 sock->state = ssock->state; 3177 3178 /* on successful connect, the msk state will be moved to established by 3179 * subflow_finish_connect() 3180 */ 3181 if (!err || err == -EINPROGRESS) 3182 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3183 else 3184 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 3185 3186 unlock: 3187 release_sock(sock->sk); 3188 return err; 3189 } 3190 3191 static int mptcp_listen(struct socket *sock, int backlog) 3192 { 3193 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3194 struct socket *ssock; 3195 int err; 3196 3197 pr_debug("msk=%p", msk); 3198 3199 lock_sock(sock->sk); 3200 ssock = __mptcp_nmpc_socket(msk); 3201 if (!ssock) { 3202 err = -EINVAL; 3203 goto unlock; 3204 } 3205 3206 mptcp_token_destroy(msk); 3207 inet_sk_state_store(sock->sk, TCP_LISTEN); 3208 sock_set_flag(sock->sk, SOCK_RCU_FREE); 3209 3210 err = ssock->ops->listen(ssock, backlog); 3211 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 3212 if (!err) 3213 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3214 3215 unlock: 3216 release_sock(sock->sk); 3217 return err; 3218 } 3219 3220 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 3221 int flags, bool kern) 3222 { 3223 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3224 struct socket *ssock; 3225 int err; 3226 3227 pr_debug("msk=%p", msk); 3228 3229 lock_sock(sock->sk); 3230 if (sock->sk->sk_state != TCP_LISTEN) 3231 goto unlock_fail; 3232 3233 ssock = __mptcp_nmpc_socket(msk); 3234 if (!ssock) 3235 goto unlock_fail; 3236 3237 clear_bit(MPTCP_DATA_READY, &msk->flags); 3238 sock_hold(ssock->sk); 3239 release_sock(sock->sk); 3240 3241 err = ssock->ops->accept(sock, newsock, flags, kern); 3242 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { 3243 struct mptcp_sock *msk = mptcp_sk(newsock->sk); 3244 struct mptcp_subflow_context *subflow; 3245 struct sock *newsk = newsock->sk; 3246 3247 lock_sock(newsk); 3248 3249 /* PM/worker can now acquire the first subflow socket 3250 * lock without racing with listener queue cleanup, 3251 * we can notify it, if needed. 3252 * 3253 * Even if remote has reset the initial subflow by now 3254 * the refcnt is still at least one. 3255 */ 3256 subflow = mptcp_subflow_ctx(msk->first); 3257 list_add(&subflow->node, &msk->conn_list); 3258 sock_hold(msk->first); 3259 if (mptcp_is_fully_established(newsk)) 3260 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL); 3261 3262 mptcp_copy_inaddrs(newsk, msk->first); 3263 mptcp_rcv_space_init(msk, msk->first); 3264 mptcp_propagate_sndbuf(newsk, msk->first); 3265 3266 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 3267 * This is needed so NOSPACE flag can be set from tcp stack. 3268 */ 3269 mptcp_flush_join_list(msk); 3270 mptcp_for_each_subflow(msk, subflow) { 3271 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3272 3273 if (!ssk->sk_socket) 3274 mptcp_sock_graft(ssk, newsock); 3275 } 3276 release_sock(newsk); 3277 } 3278 3279 if (inet_csk_listen_poll(ssock->sk)) 3280 set_bit(MPTCP_DATA_READY, &msk->flags); 3281 sock_put(ssock->sk); 3282 return err; 3283 3284 unlock_fail: 3285 release_sock(sock->sk); 3286 return -EINVAL; 3287 } 3288 3289 static __poll_t mptcp_check_readable(struct mptcp_sock *msk) 3290 { 3291 return test_bit(MPTCP_DATA_READY, &msk->flags) ? EPOLLIN | EPOLLRDNORM : 3292 0; 3293 } 3294 3295 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) 3296 { 3297 struct sock *sk = (struct sock *)msk; 3298 3299 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 3300 return EPOLLOUT | EPOLLWRNORM; 3301 3302 if (sk_stream_is_writeable(sk)) 3303 return EPOLLOUT | EPOLLWRNORM; 3304 3305 mptcp_set_nospace(sk); 3306 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 3307 if (sk_stream_is_writeable(sk)) 3308 return EPOLLOUT | EPOLLWRNORM; 3309 3310 return 0; 3311 } 3312 3313 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 3314 struct poll_table_struct *wait) 3315 { 3316 struct sock *sk = sock->sk; 3317 struct mptcp_sock *msk; 3318 __poll_t mask = 0; 3319 int state; 3320 3321 msk = mptcp_sk(sk); 3322 sock_poll_wait(file, sock, wait); 3323 3324 state = inet_sk_state_load(sk); 3325 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); 3326 if (state == TCP_LISTEN) 3327 return mptcp_check_readable(msk); 3328 3329 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 3330 mask |= mptcp_check_readable(msk); 3331 mask |= mptcp_check_writeable(msk); 3332 } 3333 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) 3334 mask |= EPOLLHUP; 3335 if (sk->sk_shutdown & RCV_SHUTDOWN) 3336 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 3337 3338 /* This barrier is coupled with smp_wmb() in tcp_reset() */ 3339 smp_rmb(); 3340 if (sk->sk_err) 3341 mask |= EPOLLERR; 3342 3343 return mask; 3344 } 3345 3346 static const struct proto_ops mptcp_stream_ops = { 3347 .family = PF_INET, 3348 .owner = THIS_MODULE, 3349 .release = inet_release, 3350 .bind = mptcp_bind, 3351 .connect = mptcp_stream_connect, 3352 .socketpair = sock_no_socketpair, 3353 .accept = mptcp_stream_accept, 3354 .getname = inet_getname, 3355 .poll = mptcp_poll, 3356 .ioctl = inet_ioctl, 3357 .gettstamp = sock_gettstamp, 3358 .listen = mptcp_listen, 3359 .shutdown = inet_shutdown, 3360 .setsockopt = sock_common_setsockopt, 3361 .getsockopt = sock_common_getsockopt, 3362 .sendmsg = inet_sendmsg, 3363 .recvmsg = inet_recvmsg, 3364 .mmap = sock_no_mmap, 3365 .sendpage = inet_sendpage, 3366 }; 3367 3368 static struct inet_protosw mptcp_protosw = { 3369 .type = SOCK_STREAM, 3370 .protocol = IPPROTO_MPTCP, 3371 .prot = &mptcp_prot, 3372 .ops = &mptcp_stream_ops, 3373 .flags = INET_PROTOSW_ICSK, 3374 }; 3375 3376 static int mptcp_napi_poll(struct napi_struct *napi, int budget) 3377 { 3378 struct mptcp_delegated_action *delegated; 3379 struct mptcp_subflow_context *subflow; 3380 int work_done = 0; 3381 3382 delegated = container_of(napi, struct mptcp_delegated_action, napi); 3383 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { 3384 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3385 3386 bh_lock_sock_nested(ssk); 3387 if (!sock_owned_by_user(ssk) && 3388 mptcp_subflow_has_delegated_action(subflow)) 3389 mptcp_subflow_process_delegated(ssk); 3390 /* ... elsewhere tcp_release_cb_override already processed 3391 * the action or will do at next release_sock(). 3392 * In both case must dequeue the subflow here - on the same 3393 * CPU that scheduled it. 3394 */ 3395 bh_unlock_sock(ssk); 3396 sock_put(ssk); 3397 3398 if (++work_done == budget) 3399 return budget; 3400 } 3401 3402 /* always provide a 0 'work_done' argument, so that napi_complete_done 3403 * will not try accessing the NULL napi->dev ptr 3404 */ 3405 napi_complete_done(napi, 0); 3406 return work_done; 3407 } 3408 3409 void __init mptcp_proto_init(void) 3410 { 3411 struct mptcp_delegated_action *delegated; 3412 int cpu; 3413 3414 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 3415 3416 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 3417 panic("Failed to allocate MPTCP pcpu counter\n"); 3418 3419 init_dummy_netdev(&mptcp_napi_dev); 3420 for_each_possible_cpu(cpu) { 3421 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); 3422 INIT_LIST_HEAD(&delegated->head); 3423 netif_tx_napi_add(&mptcp_napi_dev, &delegated->napi, mptcp_napi_poll, 3424 NAPI_POLL_WEIGHT); 3425 napi_enable(&delegated->napi); 3426 } 3427 3428 mptcp_subflow_init(); 3429 mptcp_pm_init(); 3430 mptcp_token_init(); 3431 3432 if (proto_register(&mptcp_prot, 1) != 0) 3433 panic("Failed to register MPTCP proto.\n"); 3434 3435 inet_register_protosw(&mptcp_protosw); 3436 3437 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 3438 } 3439 3440 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3441 static const struct proto_ops mptcp_v6_stream_ops = { 3442 .family = PF_INET6, 3443 .owner = THIS_MODULE, 3444 .release = inet6_release, 3445 .bind = mptcp_bind, 3446 .connect = mptcp_stream_connect, 3447 .socketpair = sock_no_socketpair, 3448 .accept = mptcp_stream_accept, 3449 .getname = inet6_getname, 3450 .poll = mptcp_poll, 3451 .ioctl = inet6_ioctl, 3452 .gettstamp = sock_gettstamp, 3453 .listen = mptcp_listen, 3454 .shutdown = inet_shutdown, 3455 .setsockopt = sock_common_setsockopt, 3456 .getsockopt = sock_common_getsockopt, 3457 .sendmsg = inet6_sendmsg, 3458 .recvmsg = inet6_recvmsg, 3459 .mmap = sock_no_mmap, 3460 .sendpage = inet_sendpage, 3461 #ifdef CONFIG_COMPAT 3462 .compat_ioctl = inet6_compat_ioctl, 3463 #endif 3464 }; 3465 3466 static struct proto mptcp_v6_prot; 3467 3468 static void mptcp_v6_destroy(struct sock *sk) 3469 { 3470 mptcp_destroy(sk); 3471 inet6_destroy_sock(sk); 3472 } 3473 3474 static struct inet_protosw mptcp_v6_protosw = { 3475 .type = SOCK_STREAM, 3476 .protocol = IPPROTO_MPTCP, 3477 .prot = &mptcp_v6_prot, 3478 .ops = &mptcp_v6_stream_ops, 3479 .flags = INET_PROTOSW_ICSK, 3480 }; 3481 3482 int __init mptcp_proto_v6_init(void) 3483 { 3484 int err; 3485 3486 mptcp_v6_prot = mptcp_prot; 3487 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 3488 mptcp_v6_prot.slab = NULL; 3489 mptcp_v6_prot.destroy = mptcp_v6_destroy; 3490 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 3491 3492 err = proto_register(&mptcp_v6_prot, 1); 3493 if (err) 3494 return err; 3495 3496 err = inet6_register_protosw(&mptcp_v6_protosw); 3497 if (err) 3498 proto_unregister(&mptcp_v6_prot); 3499 3500 return err; 3501 } 3502 #endif 3503