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 <asm/ioctls.h> 26 #include "protocol.h" 27 #include "mib.h" 28 29 #define CREATE_TRACE_POINTS 30 #include <trace/events/mptcp.h> 31 32 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 33 struct mptcp6_sock { 34 struct mptcp_sock msk; 35 struct ipv6_pinfo np; 36 }; 37 #endif 38 39 enum { 40 MPTCP_CMSG_TS = BIT(0), 41 MPTCP_CMSG_INQ = BIT(1), 42 }; 43 44 static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_smp; 45 46 static void __mptcp_destroy_sock(struct sock *sk); 47 static void __mptcp_check_send_data_fin(struct sock *sk); 48 49 DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions); 50 static struct net_device mptcp_napi_dev; 51 52 /* If msk has an initial subflow socket, and the MP_CAPABLE handshake has not 53 * completed yet or has failed, return the subflow socket. 54 * Otherwise return NULL. 55 */ 56 struct socket *__mptcp_nmpc_socket(const struct mptcp_sock *msk) 57 { 58 if (!msk->subflow || READ_ONCE(msk->can_ack)) 59 return NULL; 60 61 return msk->subflow; 62 } 63 64 /* Returns end sequence number of the receiver's advertised window */ 65 static u64 mptcp_wnd_end(const struct mptcp_sock *msk) 66 { 67 return READ_ONCE(msk->wnd_end); 68 } 69 70 static bool mptcp_is_tcpsk(struct sock *sk) 71 { 72 struct socket *sock = sk->sk_socket; 73 74 if (unlikely(sk->sk_prot == &tcp_prot)) { 75 /* we are being invoked after mptcp_accept() has 76 * accepted a non-mp-capable flow: sk is a tcp_sk, 77 * not an mptcp one. 78 * 79 * Hand the socket over to tcp so all further socket ops 80 * bypass mptcp. 81 */ 82 sock->ops = &inet_stream_ops; 83 return true; 84 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 85 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { 86 sock->ops = &inet6_stream_ops; 87 return true; 88 #endif 89 } 90 91 return false; 92 } 93 94 static int __mptcp_socket_create(struct mptcp_sock *msk) 95 { 96 struct mptcp_subflow_context *subflow; 97 struct sock *sk = (struct sock *)msk; 98 struct socket *ssock; 99 int err; 100 101 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock); 102 if (err) 103 return err; 104 105 msk->first = ssock->sk; 106 msk->subflow = ssock; 107 subflow = mptcp_subflow_ctx(ssock->sk); 108 list_add(&subflow->node, &msk->conn_list); 109 sock_hold(ssock->sk); 110 subflow->request_mptcp = 1; 111 112 /* This is the first subflow, always with id 0 */ 113 subflow->local_id_valid = 1; 114 mptcp_sock_graft(msk->first, sk->sk_socket); 115 116 return 0; 117 } 118 119 static void mptcp_drop(struct sock *sk, struct sk_buff *skb) 120 { 121 sk_drops_add(sk, skb); 122 __kfree_skb(skb); 123 } 124 125 static void mptcp_rmem_charge(struct sock *sk, int size) 126 { 127 mptcp_sk(sk)->rmem_fwd_alloc -= size; 128 } 129 130 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, 131 struct sk_buff *from) 132 { 133 bool fragstolen; 134 int delta; 135 136 if (MPTCP_SKB_CB(from)->offset || 137 !skb_try_coalesce(to, from, &fragstolen, &delta)) 138 return false; 139 140 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", 141 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, 142 to->len, MPTCP_SKB_CB(from)->end_seq); 143 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; 144 145 /* note the fwd memory can reach a negative value after accounting 146 * for the delta, but the later skb free will restore a non 147 * negative one 148 */ 149 atomic_add(delta, &sk->sk_rmem_alloc); 150 mptcp_rmem_charge(sk, delta); 151 kfree_skb_partial(from, fragstolen); 152 153 return true; 154 } 155 156 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, 157 struct sk_buff *from) 158 { 159 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) 160 return false; 161 162 return mptcp_try_coalesce((struct sock *)msk, to, from); 163 } 164 165 static void __mptcp_rmem_reclaim(struct sock *sk, int amount) 166 { 167 amount >>= PAGE_SHIFT; 168 mptcp_sk(sk)->rmem_fwd_alloc -= amount << PAGE_SHIFT; 169 __sk_mem_reduce_allocated(sk, amount); 170 } 171 172 static void mptcp_rmem_uncharge(struct sock *sk, int size) 173 { 174 struct mptcp_sock *msk = mptcp_sk(sk); 175 int reclaimable; 176 177 msk->rmem_fwd_alloc += size; 178 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk); 179 180 /* see sk_mem_uncharge() for the rationale behind the following schema */ 181 if (unlikely(reclaimable >= PAGE_SIZE)) 182 __mptcp_rmem_reclaim(sk, reclaimable); 183 } 184 185 static void mptcp_rfree(struct sk_buff *skb) 186 { 187 unsigned int len = skb->truesize; 188 struct sock *sk = skb->sk; 189 190 atomic_sub(len, &sk->sk_rmem_alloc); 191 mptcp_rmem_uncharge(sk, len); 192 } 193 194 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk) 195 { 196 skb_orphan(skb); 197 skb->sk = sk; 198 skb->destructor = mptcp_rfree; 199 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 200 mptcp_rmem_charge(sk, skb->truesize); 201 } 202 203 /* "inspired" by tcp_data_queue_ofo(), main differences: 204 * - use mptcp seqs 205 * - don't cope with sacks 206 */ 207 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) 208 { 209 struct sock *sk = (struct sock *)msk; 210 struct rb_node **p, *parent; 211 u64 seq, end_seq, max_seq; 212 struct sk_buff *skb1; 213 214 seq = MPTCP_SKB_CB(skb)->map_seq; 215 end_seq = MPTCP_SKB_CB(skb)->end_seq; 216 max_seq = atomic64_read(&msk->rcv_wnd_sent); 217 218 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, 219 RB_EMPTY_ROOT(&msk->out_of_order_queue)); 220 if (after64(end_seq, max_seq)) { 221 /* out of window */ 222 mptcp_drop(sk, skb); 223 pr_debug("oow by %lld, rcv_wnd_sent %llu\n", 224 (unsigned long long)end_seq - (unsigned long)max_seq, 225 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent)); 226 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); 227 return; 228 } 229 230 p = &msk->out_of_order_queue.rb_node; 231 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); 232 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { 233 rb_link_node(&skb->rbnode, NULL, p); 234 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 235 msk->ooo_last_skb = skb; 236 goto end; 237 } 238 239 /* with 2 subflows, adding at end of ooo queue is quite likely 240 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. 241 */ 242 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { 243 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 245 return; 246 } 247 248 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ 249 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { 250 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 251 parent = &msk->ooo_last_skb->rbnode; 252 p = &parent->rb_right; 253 goto insert; 254 } 255 256 /* Find place to insert this segment. Handle overlaps on the way. */ 257 parent = NULL; 258 while (*p) { 259 parent = *p; 260 skb1 = rb_to_skb(parent); 261 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 262 p = &parent->rb_left; 263 continue; 264 } 265 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { 266 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { 267 /* All the bits are present. Drop. */ 268 mptcp_drop(sk, skb); 269 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 270 return; 271 } 272 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 273 /* partial overlap: 274 * | skb | 275 * | skb1 | 276 * continue traversing 277 */ 278 } else { 279 /* skb's seq == skb1's seq and skb covers skb1. 280 * Replace skb1 with skb. 281 */ 282 rb_replace_node(&skb1->rbnode, &skb->rbnode, 283 &msk->out_of_order_queue); 284 mptcp_drop(sk, skb1); 285 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 286 goto merge_right; 287 } 288 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { 289 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 290 return; 291 } 292 p = &parent->rb_right; 293 } 294 295 insert: 296 /* Insert segment into RB tree. */ 297 rb_link_node(&skb->rbnode, parent, p); 298 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 299 300 merge_right: 301 /* Remove other segments covered by skb. */ 302 while ((skb1 = skb_rb_next(skb)) != NULL) { 303 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) 304 break; 305 rb_erase(&skb1->rbnode, &msk->out_of_order_queue); 306 mptcp_drop(sk, skb1); 307 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 308 } 309 /* If there is no skb after us, we are the last_skb ! */ 310 if (!skb1) 311 msk->ooo_last_skb = skb; 312 313 end: 314 skb_condense(skb); 315 mptcp_set_owner_r(skb, sk); 316 } 317 318 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size) 319 { 320 struct mptcp_sock *msk = mptcp_sk(sk); 321 int amt, amount; 322 323 if (size <= msk->rmem_fwd_alloc) 324 return true; 325 326 size -= msk->rmem_fwd_alloc; 327 amt = sk_mem_pages(size); 328 amount = amt << PAGE_SHIFT; 329 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) 330 return false; 331 332 msk->rmem_fwd_alloc += amount; 333 return true; 334 } 335 336 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 337 struct sk_buff *skb, unsigned int offset, 338 size_t copy_len) 339 { 340 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 341 struct sock *sk = (struct sock *)msk; 342 struct sk_buff *tail; 343 bool has_rxtstamp; 344 345 __skb_unlink(skb, &ssk->sk_receive_queue); 346 347 skb_ext_reset(skb); 348 skb_orphan(skb); 349 350 /* try to fetch required memory from subflow */ 351 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) 352 goto drop; 353 354 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; 355 356 /* the skb map_seq accounts for the skb offset: 357 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq 358 * value 359 */ 360 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); 361 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; 362 MPTCP_SKB_CB(skb)->offset = offset; 363 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; 364 365 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { 366 /* in sequence */ 367 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); 368 tail = skb_peek_tail(&sk->sk_receive_queue); 369 if (tail && mptcp_try_coalesce(sk, tail, skb)) 370 return true; 371 372 mptcp_set_owner_r(skb, sk); 373 __skb_queue_tail(&sk->sk_receive_queue, skb); 374 return true; 375 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { 376 mptcp_data_queue_ofo(msk, skb); 377 return false; 378 } 379 380 /* old data, keep it simple and drop the whole pkt, sender 381 * will retransmit as needed, if needed. 382 */ 383 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 384 drop: 385 mptcp_drop(sk, skb); 386 return false; 387 } 388 389 static void mptcp_stop_timer(struct sock *sk) 390 { 391 struct inet_connection_sock *icsk = inet_csk(sk); 392 393 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 394 mptcp_sk(sk)->timer_ival = 0; 395 } 396 397 static void mptcp_close_wake_up(struct sock *sk) 398 { 399 if (sock_flag(sk, SOCK_DEAD)) 400 return; 401 402 sk->sk_state_change(sk); 403 if (sk->sk_shutdown == SHUTDOWN_MASK || 404 sk->sk_state == TCP_CLOSE) 405 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 406 else 407 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 408 } 409 410 static bool mptcp_pending_data_fin_ack(struct sock *sk) 411 { 412 struct mptcp_sock *msk = mptcp_sk(sk); 413 414 return !__mptcp_check_fallback(msk) && 415 ((1 << sk->sk_state) & 416 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && 417 msk->write_seq == READ_ONCE(msk->snd_una); 418 } 419 420 static void mptcp_check_data_fin_ack(struct sock *sk) 421 { 422 struct mptcp_sock *msk = mptcp_sk(sk); 423 424 /* Look for an acknowledged DATA_FIN */ 425 if (mptcp_pending_data_fin_ack(sk)) { 426 WRITE_ONCE(msk->snd_data_fin_enable, 0); 427 428 switch (sk->sk_state) { 429 case TCP_FIN_WAIT1: 430 inet_sk_state_store(sk, TCP_FIN_WAIT2); 431 break; 432 case TCP_CLOSING: 433 case TCP_LAST_ACK: 434 inet_sk_state_store(sk, TCP_CLOSE); 435 break; 436 } 437 438 mptcp_close_wake_up(sk); 439 } 440 } 441 442 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 443 { 444 struct mptcp_sock *msk = mptcp_sk(sk); 445 446 if (READ_ONCE(msk->rcv_data_fin) && 447 ((1 << sk->sk_state) & 448 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { 449 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); 450 451 if (msk->ack_seq == rcv_data_fin_seq) { 452 if (seq) 453 *seq = rcv_data_fin_seq; 454 455 return true; 456 } 457 } 458 459 return false; 460 } 461 462 static void mptcp_set_datafin_timeout(const struct sock *sk) 463 { 464 struct inet_connection_sock *icsk = inet_csk(sk); 465 u32 retransmits; 466 467 retransmits = min_t(u32, icsk->icsk_retransmits, 468 ilog2(TCP_RTO_MAX / TCP_RTO_MIN)); 469 470 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits; 471 } 472 473 static void __mptcp_set_timeout(struct sock *sk, long tout) 474 { 475 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; 476 } 477 478 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow) 479 { 480 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 481 482 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ? 483 inet_csk(ssk)->icsk_timeout - jiffies : 0; 484 } 485 486 static void mptcp_set_timeout(struct sock *sk) 487 { 488 struct mptcp_subflow_context *subflow; 489 long tout = 0; 490 491 mptcp_for_each_subflow(mptcp_sk(sk), subflow) 492 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 493 __mptcp_set_timeout(sk, tout); 494 } 495 496 static inline bool tcp_can_send_ack(const struct sock *ssk) 497 { 498 return !((1 << inet_sk_state_load(ssk)) & 499 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); 500 } 501 502 void __mptcp_subflow_send_ack(struct sock *ssk) 503 { 504 if (tcp_can_send_ack(ssk)) 505 tcp_send_ack(ssk); 506 } 507 508 static void mptcp_subflow_send_ack(struct sock *ssk) 509 { 510 bool slow; 511 512 slow = lock_sock_fast(ssk); 513 __mptcp_subflow_send_ack(ssk); 514 unlock_sock_fast(ssk, slow); 515 } 516 517 static void mptcp_send_ack(struct mptcp_sock *msk) 518 { 519 struct mptcp_subflow_context *subflow; 520 521 mptcp_for_each_subflow(msk, subflow) 522 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow)); 523 } 524 525 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk) 526 { 527 bool slow; 528 529 slow = lock_sock_fast(ssk); 530 if (tcp_can_send_ack(ssk)) 531 tcp_cleanup_rbuf(ssk, 1); 532 unlock_sock_fast(ssk, slow); 533 } 534 535 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty) 536 { 537 const struct inet_connection_sock *icsk = inet_csk(ssk); 538 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending); 539 const struct tcp_sock *tp = tcp_sk(ssk); 540 541 return (ack_pending & ICSK_ACK_SCHED) && 542 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) > 543 READ_ONCE(icsk->icsk_ack.rcv_mss)) || 544 (rx_empty && ack_pending & 545 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED))); 546 } 547 548 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) 549 { 550 int old_space = READ_ONCE(msk->old_wspace); 551 struct mptcp_subflow_context *subflow; 552 struct sock *sk = (struct sock *)msk; 553 int space = __mptcp_space(sk); 554 bool cleanup, rx_empty; 555 556 cleanup = (space > 0) && (space >= (old_space << 1)); 557 rx_empty = !__mptcp_rmem(sk); 558 559 mptcp_for_each_subflow(msk, subflow) { 560 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 561 562 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty)) 563 mptcp_subflow_cleanup_rbuf(ssk); 564 } 565 } 566 567 static bool mptcp_check_data_fin(struct sock *sk) 568 { 569 struct mptcp_sock *msk = mptcp_sk(sk); 570 u64 rcv_data_fin_seq; 571 bool ret = false; 572 573 if (__mptcp_check_fallback(msk)) 574 return ret; 575 576 /* Need to ack a DATA_FIN received from a peer while this side 577 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. 578 * msk->rcv_data_fin was set when parsing the incoming options 579 * at the subflow level and the msk lock was not held, so this 580 * is the first opportunity to act on the DATA_FIN and change 581 * the msk state. 582 * 583 * If we are caught up to the sequence number of the incoming 584 * DATA_FIN, send the DATA_ACK now and do state transition. If 585 * not caught up, do nothing and let the recv code send DATA_ACK 586 * when catching up. 587 */ 588 589 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { 590 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); 591 WRITE_ONCE(msk->rcv_data_fin, 0); 592 593 sk->sk_shutdown |= RCV_SHUTDOWN; 594 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 595 596 switch (sk->sk_state) { 597 case TCP_ESTABLISHED: 598 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 599 break; 600 case TCP_FIN_WAIT1: 601 inet_sk_state_store(sk, TCP_CLOSING); 602 break; 603 case TCP_FIN_WAIT2: 604 inet_sk_state_store(sk, TCP_CLOSE); 605 break; 606 default: 607 /* Other states not expected */ 608 WARN_ON_ONCE(1); 609 break; 610 } 611 612 ret = true; 613 mptcp_send_ack(msk); 614 mptcp_close_wake_up(sk); 615 } 616 return ret; 617 } 618 619 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 620 struct sock *ssk, 621 unsigned int *bytes) 622 { 623 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 624 struct sock *sk = (struct sock *)msk; 625 unsigned int moved = 0; 626 bool more_data_avail; 627 struct tcp_sock *tp; 628 bool done = false; 629 int sk_rbuf; 630 631 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 632 633 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 634 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 635 636 if (unlikely(ssk_rbuf > sk_rbuf)) { 637 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); 638 sk_rbuf = ssk_rbuf; 639 } 640 } 641 642 pr_debug("msk=%p ssk=%p", msk, ssk); 643 tp = tcp_sk(ssk); 644 do { 645 u32 map_remaining, offset; 646 u32 seq = tp->copied_seq; 647 struct sk_buff *skb; 648 bool fin; 649 650 /* try to move as much data as available */ 651 map_remaining = subflow->map_data_len - 652 mptcp_subflow_get_map_offset(subflow); 653 654 skb = skb_peek(&ssk->sk_receive_queue); 655 if (!skb) { 656 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(), 657 * a different CPU can have already processed the pending 658 * data, stop here or we can enter an infinite loop 659 */ 660 if (!moved) 661 done = true; 662 break; 663 } 664 665 if (__mptcp_check_fallback(msk)) { 666 /* Under fallback skbs have no MPTCP extension and TCP could 667 * collapse them between the dummy map creation and the 668 * current dequeue. Be sure to adjust the map size. 669 */ 670 map_remaining = skb->len; 671 subflow->map_data_len = skb->len; 672 } 673 674 offset = seq - TCP_SKB_CB(skb)->seq; 675 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; 676 if (fin) { 677 done = true; 678 seq++; 679 } 680 681 if (offset < skb->len) { 682 size_t len = skb->len - offset; 683 684 if (tp->urg_data) 685 done = true; 686 687 if (__mptcp_move_skb(msk, ssk, skb, offset, len)) 688 moved += len; 689 seq += len; 690 691 if (WARN_ON_ONCE(map_remaining < len)) 692 break; 693 } else { 694 WARN_ON_ONCE(!fin); 695 sk_eat_skb(ssk, skb); 696 done = true; 697 } 698 699 WRITE_ONCE(tp->copied_seq, seq); 700 more_data_avail = mptcp_subflow_data_available(ssk); 701 702 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { 703 done = true; 704 break; 705 } 706 } while (more_data_avail); 707 708 *bytes += moved; 709 return done; 710 } 711 712 static bool __mptcp_ofo_queue(struct mptcp_sock *msk) 713 { 714 struct sock *sk = (struct sock *)msk; 715 struct sk_buff *skb, *tail; 716 bool moved = false; 717 struct rb_node *p; 718 u64 end_seq; 719 720 p = rb_first(&msk->out_of_order_queue); 721 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); 722 while (p) { 723 skb = rb_to_skb(p); 724 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) 725 break; 726 727 p = rb_next(p); 728 rb_erase(&skb->rbnode, &msk->out_of_order_queue); 729 730 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, 731 msk->ack_seq))) { 732 mptcp_drop(sk, skb); 733 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 734 continue; 735 } 736 737 end_seq = MPTCP_SKB_CB(skb)->end_seq; 738 tail = skb_peek_tail(&sk->sk_receive_queue); 739 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { 740 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 741 742 /* skip overlapping data, if any */ 743 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", 744 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, 745 delta); 746 MPTCP_SKB_CB(skb)->offset += delta; 747 MPTCP_SKB_CB(skb)->map_seq += delta; 748 __skb_queue_tail(&sk->sk_receive_queue, skb); 749 } 750 msk->ack_seq = end_seq; 751 moved = true; 752 } 753 return moved; 754 } 755 756 /* In most cases we will be able to lock the mptcp socket. If its already 757 * owned, we need to defer to the work queue to avoid ABBA deadlock. 758 */ 759 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 760 { 761 struct sock *sk = (struct sock *)msk; 762 unsigned int moved = 0; 763 764 __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 765 __mptcp_ofo_queue(msk); 766 if (unlikely(ssk->sk_err)) { 767 if (!sock_owned_by_user(sk)) 768 __mptcp_error_report(sk); 769 else 770 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags); 771 } 772 773 /* If the moves have caught up with the DATA_FIN sequence number 774 * it's time to ack the DATA_FIN and change socket state, but 775 * this is not a good place to change state. Let the workqueue 776 * do it. 777 */ 778 if (mptcp_pending_data_fin(sk, NULL)) 779 mptcp_schedule_work(sk); 780 return moved > 0; 781 } 782 783 void mptcp_data_ready(struct sock *sk, struct sock *ssk) 784 { 785 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 786 struct mptcp_sock *msk = mptcp_sk(sk); 787 int sk_rbuf, ssk_rbuf; 788 789 /* The peer can send data while we are shutting down this 790 * subflow at msk destruction time, but we must avoid enqueuing 791 * more data to the msk receive queue 792 */ 793 if (unlikely(subflow->disposable)) 794 return; 795 796 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 797 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 798 if (unlikely(ssk_rbuf > sk_rbuf)) 799 sk_rbuf = ssk_rbuf; 800 801 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ 802 if (__mptcp_rmem(sk) > sk_rbuf) { 803 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); 804 return; 805 } 806 807 /* Wake-up the reader only for in-sequence data */ 808 mptcp_data_lock(sk); 809 if (move_skbs_to_msk(msk, ssk)) 810 sk->sk_data_ready(sk); 811 812 mptcp_data_unlock(sk); 813 } 814 815 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) 816 { 817 struct sock *sk = (struct sock *)msk; 818 819 if (sk->sk_state != TCP_ESTABLISHED) 820 return false; 821 822 /* attach to msk socket only after we are sure we will deal with it 823 * at close time 824 */ 825 if (sk->sk_socket && !ssk->sk_socket) 826 mptcp_sock_graft(ssk, sk->sk_socket); 827 828 mptcp_propagate_sndbuf((struct sock *)msk, ssk); 829 mptcp_sockopt_sync_locked(msk, ssk); 830 return true; 831 } 832 833 static void __mptcp_flush_join_list(struct sock *sk) 834 { 835 struct mptcp_subflow_context *tmp, *subflow; 836 struct mptcp_sock *msk = mptcp_sk(sk); 837 838 list_for_each_entry_safe(subflow, tmp, &msk->join_list, node) { 839 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 840 bool slow = lock_sock_fast(ssk); 841 842 list_move_tail(&subflow->node, &msk->conn_list); 843 if (!__mptcp_finish_join(msk, ssk)) 844 mptcp_subflow_reset(ssk); 845 unlock_sock_fast(ssk, slow); 846 } 847 } 848 849 static bool mptcp_timer_pending(struct sock *sk) 850 { 851 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); 852 } 853 854 static void mptcp_reset_timer(struct sock *sk) 855 { 856 struct inet_connection_sock *icsk = inet_csk(sk); 857 unsigned long tout; 858 859 /* prevent rescheduling on close */ 860 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) 861 return; 862 863 tout = mptcp_sk(sk)->timer_ival; 864 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); 865 } 866 867 bool mptcp_schedule_work(struct sock *sk) 868 { 869 if (inet_sk_state_load(sk) != TCP_CLOSE && 870 schedule_work(&mptcp_sk(sk)->work)) { 871 /* each subflow already holds a reference to the sk, and the 872 * workqueue is invoked by a subflow, so sk can't go away here. 873 */ 874 sock_hold(sk); 875 return true; 876 } 877 return false; 878 } 879 880 void mptcp_subflow_eof(struct sock *sk) 881 { 882 if (!test_and_set_bit(MPTCP_WORK_EOF, &mptcp_sk(sk)->flags)) 883 mptcp_schedule_work(sk); 884 } 885 886 static void mptcp_check_for_eof(struct mptcp_sock *msk) 887 { 888 struct mptcp_subflow_context *subflow; 889 struct sock *sk = (struct sock *)msk; 890 int receivers = 0; 891 892 mptcp_for_each_subflow(msk, subflow) 893 receivers += !subflow->rx_eof; 894 if (receivers) 895 return; 896 897 if (!(sk->sk_shutdown & RCV_SHUTDOWN)) { 898 /* hopefully temporary hack: propagate shutdown status 899 * to msk, when all subflows agree on it 900 */ 901 sk->sk_shutdown |= RCV_SHUTDOWN; 902 903 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 904 sk->sk_data_ready(sk); 905 } 906 907 switch (sk->sk_state) { 908 case TCP_ESTABLISHED: 909 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 910 break; 911 case TCP_FIN_WAIT1: 912 inet_sk_state_store(sk, TCP_CLOSING); 913 break; 914 case TCP_FIN_WAIT2: 915 inet_sk_state_store(sk, TCP_CLOSE); 916 break; 917 default: 918 return; 919 } 920 mptcp_close_wake_up(sk); 921 } 922 923 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) 924 { 925 struct mptcp_subflow_context *subflow; 926 struct sock *sk = (struct sock *)msk; 927 928 sock_owned_by_me(sk); 929 930 mptcp_for_each_subflow(msk, subflow) { 931 if (READ_ONCE(subflow->data_avail)) 932 return mptcp_subflow_tcp_sock(subflow); 933 } 934 935 return NULL; 936 } 937 938 static bool mptcp_skb_can_collapse_to(u64 write_seq, 939 const struct sk_buff *skb, 940 const struct mptcp_ext *mpext) 941 { 942 if (!tcp_skb_can_collapse_to(skb)) 943 return false; 944 945 /* can collapse only if MPTCP level sequence is in order and this 946 * mapping has not been xmitted yet 947 */ 948 return mpext && mpext->data_seq + mpext->data_len == write_seq && 949 !mpext->frozen; 950 } 951 952 /* we can append data to the given data frag if: 953 * - there is space available in the backing page_frag 954 * - the data frag tail matches the current page_frag free offset 955 * - the data frag end sequence number matches the current write seq 956 */ 957 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 958 const struct page_frag *pfrag, 959 const struct mptcp_data_frag *df) 960 { 961 return df && pfrag->page == df->page && 962 pfrag->size - pfrag->offset > 0 && 963 pfrag->offset == (df->offset + df->data_len) && 964 df->data_seq + df->data_len == msk->write_seq; 965 } 966 967 static void dfrag_uncharge(struct sock *sk, int len) 968 { 969 sk_mem_uncharge(sk, len); 970 sk_wmem_queued_add(sk, -len); 971 } 972 973 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 974 { 975 int len = dfrag->data_len + dfrag->overhead; 976 977 list_del(&dfrag->list); 978 dfrag_uncharge(sk, len); 979 put_page(dfrag->page); 980 } 981 982 static void __mptcp_clean_una(struct sock *sk) 983 { 984 struct mptcp_sock *msk = mptcp_sk(sk); 985 struct mptcp_data_frag *dtmp, *dfrag; 986 u64 snd_una; 987 988 /* on fallback we just need to ignore snd_una, as this is really 989 * plain TCP 990 */ 991 if (__mptcp_check_fallback(msk)) 992 msk->snd_una = READ_ONCE(msk->snd_nxt); 993 994 snd_una = msk->snd_una; 995 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 996 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 997 break; 998 999 if (unlikely(dfrag == msk->first_pending)) { 1000 /* in recovery mode can see ack after the current snd head */ 1001 if (WARN_ON_ONCE(!msk->recovery)) 1002 break; 1003 1004 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1005 } 1006 1007 dfrag_clear(sk, dfrag); 1008 } 1009 1010 dfrag = mptcp_rtx_head(sk); 1011 if (dfrag && after64(snd_una, dfrag->data_seq)) { 1012 u64 delta = snd_una - dfrag->data_seq; 1013 1014 /* prevent wrap around in recovery mode */ 1015 if (unlikely(delta > dfrag->already_sent)) { 1016 if (WARN_ON_ONCE(!msk->recovery)) 1017 goto out; 1018 if (WARN_ON_ONCE(delta > dfrag->data_len)) 1019 goto out; 1020 dfrag->already_sent += delta - dfrag->already_sent; 1021 } 1022 1023 dfrag->data_seq += delta; 1024 dfrag->offset += delta; 1025 dfrag->data_len -= delta; 1026 dfrag->already_sent -= delta; 1027 1028 dfrag_uncharge(sk, delta); 1029 } 1030 1031 /* all retransmitted data acked, recovery completed */ 1032 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) 1033 msk->recovery = false; 1034 1035 out: 1036 if (snd_una == READ_ONCE(msk->snd_nxt) && 1037 snd_una == READ_ONCE(msk->write_seq)) { 1038 if (mptcp_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) 1039 mptcp_stop_timer(sk); 1040 } else { 1041 mptcp_reset_timer(sk); 1042 } 1043 } 1044 1045 static void __mptcp_clean_una_wakeup(struct sock *sk) 1046 { 1047 lockdep_assert_held_once(&sk->sk_lock.slock); 1048 1049 __mptcp_clean_una(sk); 1050 mptcp_write_space(sk); 1051 } 1052 1053 static void mptcp_clean_una_wakeup(struct sock *sk) 1054 { 1055 mptcp_data_lock(sk); 1056 __mptcp_clean_una_wakeup(sk); 1057 mptcp_data_unlock(sk); 1058 } 1059 1060 static void mptcp_enter_memory_pressure(struct sock *sk) 1061 { 1062 struct mptcp_subflow_context *subflow; 1063 struct mptcp_sock *msk = mptcp_sk(sk); 1064 bool first = true; 1065 1066 sk_stream_moderate_sndbuf(sk); 1067 mptcp_for_each_subflow(msk, subflow) { 1068 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1069 1070 if (first) 1071 tcp_enter_memory_pressure(ssk); 1072 sk_stream_moderate_sndbuf(ssk); 1073 first = false; 1074 } 1075 } 1076 1077 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 1078 * data 1079 */ 1080 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 1081 { 1082 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 1083 pfrag, sk->sk_allocation))) 1084 return true; 1085 1086 mptcp_enter_memory_pressure(sk); 1087 return false; 1088 } 1089 1090 static struct mptcp_data_frag * 1091 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 1092 int orig_offset) 1093 { 1094 int offset = ALIGN(orig_offset, sizeof(long)); 1095 struct mptcp_data_frag *dfrag; 1096 1097 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 1098 dfrag->data_len = 0; 1099 dfrag->data_seq = msk->write_seq; 1100 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 1101 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 1102 dfrag->already_sent = 0; 1103 dfrag->page = pfrag->page; 1104 1105 return dfrag; 1106 } 1107 1108 struct mptcp_sendmsg_info { 1109 int mss_now; 1110 int size_goal; 1111 u16 limit; 1112 u16 sent; 1113 unsigned int flags; 1114 bool data_lock_held; 1115 }; 1116 1117 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk, 1118 u64 data_seq, int avail_size) 1119 { 1120 u64 window_end = mptcp_wnd_end(msk); 1121 u64 mptcp_snd_wnd; 1122 1123 if (__mptcp_check_fallback(msk)) 1124 return avail_size; 1125 1126 mptcp_snd_wnd = window_end - data_seq; 1127 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size); 1128 1129 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) { 1130 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd); 1131 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED); 1132 } 1133 1134 return avail_size; 1135 } 1136 1137 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) 1138 { 1139 struct skb_ext *mpext = __skb_ext_alloc(gfp); 1140 1141 if (!mpext) 1142 return false; 1143 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); 1144 return true; 1145 } 1146 1147 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) 1148 { 1149 struct sk_buff *skb; 1150 1151 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); 1152 if (likely(skb)) { 1153 if (likely(__mptcp_add_ext(skb, gfp))) { 1154 skb_reserve(skb, MAX_TCP_HEADER); 1155 skb->ip_summed = CHECKSUM_PARTIAL; 1156 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); 1157 return skb; 1158 } 1159 __kfree_skb(skb); 1160 } else { 1161 mptcp_enter_memory_pressure(sk); 1162 } 1163 return NULL; 1164 } 1165 1166 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) 1167 { 1168 struct sk_buff *skb; 1169 1170 skb = __mptcp_do_alloc_tx_skb(sk, gfp); 1171 if (!skb) 1172 return NULL; 1173 1174 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1175 tcp_skb_entail(ssk, skb); 1176 return skb; 1177 } 1178 tcp_skb_tsorted_anchor_cleanup(skb); 1179 kfree_skb(skb); 1180 return NULL; 1181 } 1182 1183 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) 1184 { 1185 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; 1186 1187 return __mptcp_alloc_tx_skb(sk, ssk, gfp); 1188 } 1189 1190 /* note: this always recompute the csum on the whole skb, even 1191 * if we just appended a single frag. More status info needed 1192 */ 1193 static void mptcp_update_data_checksum(struct sk_buff *skb, int added) 1194 { 1195 struct mptcp_ext *mpext = mptcp_get_ext(skb); 1196 __wsum csum = ~csum_unfold(mpext->csum); 1197 int offset = skb->len - added; 1198 1199 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset)); 1200 } 1201 1202 static void mptcp_update_infinite_map(struct mptcp_sock *msk, 1203 struct sock *ssk, 1204 struct mptcp_ext *mpext) 1205 { 1206 if (!mpext) 1207 return; 1208 1209 mpext->infinite_map = 1; 1210 mpext->data_len = 0; 1211 1212 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); 1213 mptcp_subflow_ctx(ssk)->send_infinite_map = 0; 1214 pr_fallback(msk); 1215 mptcp_do_fallback(ssk); 1216 } 1217 1218 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 1219 struct mptcp_data_frag *dfrag, 1220 struct mptcp_sendmsg_info *info) 1221 { 1222 u64 data_seq = dfrag->data_seq + info->sent; 1223 int offset = dfrag->offset + info->sent; 1224 struct mptcp_sock *msk = mptcp_sk(sk); 1225 bool zero_window_probe = false; 1226 struct mptcp_ext *mpext = NULL; 1227 bool can_coalesce = false; 1228 bool reuse_skb = true; 1229 struct sk_buff *skb; 1230 size_t copy; 1231 int i; 1232 1233 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", 1234 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); 1235 1236 if (WARN_ON_ONCE(info->sent > info->limit || 1237 info->limit > dfrag->data_len)) 1238 return 0; 1239 1240 if (unlikely(!__tcp_can_send(ssk))) 1241 return -EAGAIN; 1242 1243 /* compute send limit */ 1244 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); 1245 copy = info->size_goal; 1246 1247 skb = tcp_write_queue_tail(ssk); 1248 if (skb && copy > skb->len) { 1249 /* Limit the write to the size available in the 1250 * current skb, if any, so that we create at most a new skb. 1251 * Explicitly tells TCP internals to avoid collapsing on later 1252 * queue management operation, to avoid breaking the ext <-> 1253 * SSN association set here 1254 */ 1255 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1256 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { 1257 TCP_SKB_CB(skb)->eor = 1; 1258 goto alloc_skb; 1259 } 1260 1261 i = skb_shinfo(skb)->nr_frags; 1262 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); 1263 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) { 1264 tcp_mark_push(tcp_sk(ssk), skb); 1265 goto alloc_skb; 1266 } 1267 1268 copy -= skb->len; 1269 } else { 1270 alloc_skb: 1271 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held); 1272 if (!skb) 1273 return -ENOMEM; 1274 1275 i = skb_shinfo(skb)->nr_frags; 1276 reuse_skb = false; 1277 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1278 } 1279 1280 /* Zero window and all data acked? Probe. */ 1281 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy); 1282 if (copy == 0) { 1283 u64 snd_una = READ_ONCE(msk->snd_una); 1284 1285 if (snd_una != msk->snd_nxt) { 1286 tcp_remove_empty_skb(ssk); 1287 return 0; 1288 } 1289 1290 zero_window_probe = true; 1291 data_seq = snd_una - 1; 1292 copy = 1; 1293 1294 /* all mptcp-level data is acked, no skbs should be present into the 1295 * ssk write queue 1296 */ 1297 WARN_ON_ONCE(reuse_skb); 1298 } 1299 1300 copy = min_t(size_t, copy, info->limit - info->sent); 1301 if (!sk_wmem_schedule(ssk, copy)) { 1302 tcp_remove_empty_skb(ssk); 1303 return -ENOMEM; 1304 } 1305 1306 if (can_coalesce) { 1307 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1308 } else { 1309 get_page(dfrag->page); 1310 skb_fill_page_desc(skb, i, dfrag->page, offset, copy); 1311 } 1312 1313 skb->len += copy; 1314 skb->data_len += copy; 1315 skb->truesize += copy; 1316 sk_wmem_queued_add(ssk, copy); 1317 sk_mem_charge(ssk, copy); 1318 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy); 1319 TCP_SKB_CB(skb)->end_seq += copy; 1320 tcp_skb_pcount_set(skb, 0); 1321 1322 /* on skb reuse we just need to update the DSS len */ 1323 if (reuse_skb) { 1324 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1325 mpext->data_len += copy; 1326 WARN_ON_ONCE(zero_window_probe); 1327 goto out; 1328 } 1329 1330 memset(mpext, 0, sizeof(*mpext)); 1331 mpext->data_seq = data_seq; 1332 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 1333 mpext->data_len = copy; 1334 mpext->use_map = 1; 1335 mpext->dsn64 = 1; 1336 1337 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 1338 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 1339 mpext->dsn64); 1340 1341 if (zero_window_probe) { 1342 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1343 mpext->frozen = 1; 1344 if (READ_ONCE(msk->csum_enabled)) 1345 mptcp_update_data_checksum(skb, copy); 1346 tcp_push_pending_frames(ssk); 1347 return 0; 1348 } 1349 out: 1350 if (READ_ONCE(msk->csum_enabled)) 1351 mptcp_update_data_checksum(skb, copy); 1352 if (mptcp_subflow_ctx(ssk)->send_infinite_map) 1353 mptcp_update_infinite_map(msk, ssk, mpext); 1354 trace_mptcp_sendmsg_frag(mpext); 1355 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1356 return copy; 1357 } 1358 1359 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ 1360 sizeof(struct tcphdr) - \ 1361 MAX_TCP_OPTION_SPACE - \ 1362 sizeof(struct ipv6hdr) - \ 1363 sizeof(struct frag_hdr)) 1364 1365 struct subflow_send_info { 1366 struct sock *ssk; 1367 u64 linger_time; 1368 }; 1369 1370 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow) 1371 { 1372 if (!subflow->stale) 1373 return; 1374 1375 subflow->stale = 0; 1376 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER); 1377 } 1378 1379 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) 1380 { 1381 if (unlikely(subflow->stale)) { 1382 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp); 1383 1384 if (subflow->stale_rcv_tstamp == rcv_tstamp) 1385 return false; 1386 1387 mptcp_subflow_set_active(subflow); 1388 } 1389 return __mptcp_subflow_active(subflow); 1390 } 1391 1392 #define SSK_MODE_ACTIVE 0 1393 #define SSK_MODE_BACKUP 1 1394 #define SSK_MODE_MAX 2 1395 1396 /* implement the mptcp packet scheduler; 1397 * returns the subflow that will transmit the next DSS 1398 * additionally updates the rtx timeout 1399 */ 1400 static struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 1401 { 1402 struct subflow_send_info send_info[SSK_MODE_MAX]; 1403 struct mptcp_subflow_context *subflow; 1404 struct sock *sk = (struct sock *)msk; 1405 u32 pace, burst, wmem; 1406 int i, nr_active = 0; 1407 struct sock *ssk; 1408 u64 linger_time; 1409 long tout = 0; 1410 1411 sock_owned_by_me(sk); 1412 1413 if (__mptcp_check_fallback(msk)) { 1414 if (!msk->first) 1415 return NULL; 1416 return __tcp_can_send(msk->first) && 1417 sk_stream_memory_free(msk->first) ? msk->first : NULL; 1418 } 1419 1420 /* re-use last subflow, if the burst allow that */ 1421 if (msk->last_snd && msk->snd_burst > 0 && 1422 sk_stream_memory_free(msk->last_snd) && 1423 mptcp_subflow_active(mptcp_subflow_ctx(msk->last_snd))) { 1424 mptcp_set_timeout(sk); 1425 return msk->last_snd; 1426 } 1427 1428 /* pick the subflow with the lower wmem/wspace ratio */ 1429 for (i = 0; i < SSK_MODE_MAX; ++i) { 1430 send_info[i].ssk = NULL; 1431 send_info[i].linger_time = -1; 1432 } 1433 1434 mptcp_for_each_subflow(msk, subflow) { 1435 trace_mptcp_subflow_get_send(subflow); 1436 ssk = mptcp_subflow_tcp_sock(subflow); 1437 if (!mptcp_subflow_active(subflow)) 1438 continue; 1439 1440 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 1441 nr_active += !subflow->backup; 1442 pace = subflow->avg_pacing_rate; 1443 if (unlikely(!pace)) { 1444 /* init pacing rate from socket */ 1445 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate); 1446 pace = subflow->avg_pacing_rate; 1447 if (!pace) 1448 continue; 1449 } 1450 1451 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); 1452 if (linger_time < send_info[subflow->backup].linger_time) { 1453 send_info[subflow->backup].ssk = ssk; 1454 send_info[subflow->backup].linger_time = linger_time; 1455 } 1456 } 1457 __mptcp_set_timeout(sk, tout); 1458 1459 /* pick the best backup if no other subflow is active */ 1460 if (!nr_active) 1461 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk; 1462 1463 /* According to the blest algorithm, to avoid HoL blocking for the 1464 * faster flow, we need to: 1465 * - estimate the faster flow linger time 1466 * - use the above to estimate the amount of byte transferred 1467 * by the faster flow 1468 * - check that the amount of queued data is greter than the above, 1469 * otherwise do not use the picked, slower, subflow 1470 * We select the subflow with the shorter estimated time to flush 1471 * the queued mem, which basically ensure the above. We just need 1472 * to check that subflow has a non empty cwin. 1473 */ 1474 ssk = send_info[SSK_MODE_ACTIVE].ssk; 1475 if (!ssk || !sk_stream_memory_free(ssk)) 1476 return NULL; 1477 1478 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt); 1479 wmem = READ_ONCE(ssk->sk_wmem_queued); 1480 if (!burst) { 1481 msk->last_snd = NULL; 1482 return ssk; 1483 } 1484 1485 subflow = mptcp_subflow_ctx(ssk); 1486 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem + 1487 READ_ONCE(ssk->sk_pacing_rate) * burst, 1488 burst + wmem); 1489 msk->last_snd = ssk; 1490 msk->snd_burst = burst; 1491 return ssk; 1492 } 1493 1494 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) 1495 { 1496 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); 1497 release_sock(ssk); 1498 } 1499 1500 static void mptcp_update_post_push(struct mptcp_sock *msk, 1501 struct mptcp_data_frag *dfrag, 1502 u32 sent) 1503 { 1504 u64 snd_nxt_new = dfrag->data_seq; 1505 1506 dfrag->already_sent += sent; 1507 1508 msk->snd_burst -= sent; 1509 1510 snd_nxt_new += dfrag->already_sent; 1511 1512 /* snd_nxt_new can be smaller than snd_nxt in case mptcp 1513 * is recovering after a failover. In that event, this re-sends 1514 * old segments. 1515 * 1516 * Thus compute snd_nxt_new candidate based on 1517 * the dfrag->data_seq that was sent and the data 1518 * that has been handed to the subflow for transmission 1519 * and skip update in case it was old dfrag. 1520 */ 1521 if (likely(after64(snd_nxt_new, msk->snd_nxt))) 1522 msk->snd_nxt = snd_nxt_new; 1523 } 1524 1525 void mptcp_check_and_set_pending(struct sock *sk) 1526 { 1527 if (mptcp_send_head(sk)) 1528 mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING); 1529 } 1530 1531 void __mptcp_push_pending(struct sock *sk, unsigned int flags) 1532 { 1533 struct sock *prev_ssk = NULL, *ssk = NULL; 1534 struct mptcp_sock *msk = mptcp_sk(sk); 1535 struct mptcp_sendmsg_info info = { 1536 .flags = flags, 1537 }; 1538 bool do_check_data_fin = false; 1539 struct mptcp_data_frag *dfrag; 1540 int len; 1541 1542 while ((dfrag = mptcp_send_head(sk))) { 1543 info.sent = dfrag->already_sent; 1544 info.limit = dfrag->data_len; 1545 len = dfrag->data_len - dfrag->already_sent; 1546 while (len > 0) { 1547 int ret = 0; 1548 1549 prev_ssk = ssk; 1550 ssk = mptcp_subflow_get_send(msk); 1551 1552 /* First check. If the ssk has changed since 1553 * the last round, release prev_ssk 1554 */ 1555 if (ssk != prev_ssk && prev_ssk) 1556 mptcp_push_release(prev_ssk, &info); 1557 if (!ssk) 1558 goto out; 1559 1560 /* Need to lock the new subflow only if different 1561 * from the previous one, otherwise we are still 1562 * helding the relevant lock 1563 */ 1564 if (ssk != prev_ssk) 1565 lock_sock(ssk); 1566 1567 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1568 if (ret <= 0) { 1569 if (ret == -EAGAIN) 1570 continue; 1571 mptcp_push_release(ssk, &info); 1572 goto out; 1573 } 1574 1575 do_check_data_fin = true; 1576 info.sent += ret; 1577 len -= ret; 1578 1579 mptcp_update_post_push(msk, dfrag, ret); 1580 } 1581 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1582 } 1583 1584 /* at this point we held the socket lock for the last subflow we used */ 1585 if (ssk) 1586 mptcp_push_release(ssk, &info); 1587 1588 out: 1589 /* ensure the rtx timer is running */ 1590 if (!mptcp_timer_pending(sk)) 1591 mptcp_reset_timer(sk); 1592 if (do_check_data_fin) 1593 __mptcp_check_send_data_fin(sk); 1594 } 1595 1596 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) 1597 { 1598 struct mptcp_sock *msk = mptcp_sk(sk); 1599 struct mptcp_sendmsg_info info = { 1600 .data_lock_held = true, 1601 }; 1602 struct mptcp_data_frag *dfrag; 1603 struct sock *xmit_ssk; 1604 int len, copied = 0; 1605 1606 info.flags = 0; 1607 while ((dfrag = mptcp_send_head(sk))) { 1608 info.sent = dfrag->already_sent; 1609 info.limit = dfrag->data_len; 1610 len = dfrag->data_len - dfrag->already_sent; 1611 while (len > 0) { 1612 int ret = 0; 1613 1614 /* check for a different subflow usage only after 1615 * spooling the first chunk of data 1616 */ 1617 xmit_ssk = first ? ssk : mptcp_subflow_get_send(msk); 1618 if (!xmit_ssk) 1619 goto out; 1620 if (xmit_ssk != ssk) { 1621 mptcp_subflow_delegate(mptcp_subflow_ctx(xmit_ssk), 1622 MPTCP_DELEGATE_SEND); 1623 goto out; 1624 } 1625 1626 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 1627 if (ret <= 0) 1628 goto out; 1629 1630 info.sent += ret; 1631 copied += ret; 1632 len -= ret; 1633 first = false; 1634 1635 mptcp_update_post_push(msk, dfrag, ret); 1636 } 1637 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1638 } 1639 1640 out: 1641 /* __mptcp_alloc_tx_skb could have released some wmem and we are 1642 * not going to flush it via release_sock() 1643 */ 1644 if (copied) { 1645 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 1646 info.size_goal); 1647 if (!mptcp_timer_pending(sk)) 1648 mptcp_reset_timer(sk); 1649 1650 if (msk->snd_data_fin_enable && 1651 msk->snd_nxt + 1 == msk->write_seq) 1652 mptcp_schedule_work(sk); 1653 } 1654 } 1655 1656 static void mptcp_set_nospace(struct sock *sk) 1657 { 1658 /* enable autotune */ 1659 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1660 1661 /* will be cleared on avail space */ 1662 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); 1663 } 1664 1665 static int mptcp_disconnect(struct sock *sk, int flags); 1666 1667 static int mptcp_sendmsg_fastopen(struct sock *sk, struct sock *ssk, struct msghdr *msg, 1668 size_t len, int *copied_syn) 1669 { 1670 unsigned int saved_flags = msg->msg_flags; 1671 struct mptcp_sock *msk = mptcp_sk(sk); 1672 int ret; 1673 1674 lock_sock(ssk); 1675 msg->msg_flags |= MSG_DONTWAIT; 1676 msk->connect_flags = O_NONBLOCK; 1677 msk->fastopening = 1; 1678 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL); 1679 msk->fastopening = 0; 1680 msg->msg_flags = saved_flags; 1681 release_sock(ssk); 1682 1683 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */ 1684 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) { 1685 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1686 msg->msg_namelen, msg->msg_flags, 1); 1687 1688 /* Keep the same behaviour of plain TCP: zero the copied bytes in 1689 * case of any error, except timeout or signal 1690 */ 1691 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) 1692 *copied_syn = 0; 1693 } else if (ret && ret != -EINPROGRESS) { 1694 mptcp_disconnect(sk, 0); 1695 } 1696 1697 return ret; 1698 } 1699 1700 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1701 { 1702 struct mptcp_sock *msk = mptcp_sk(sk); 1703 struct page_frag *pfrag; 1704 struct socket *ssock; 1705 size_t copied = 0; 1706 int ret = 0; 1707 long timeo; 1708 1709 /* silently ignore everything else */ 1710 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN; 1711 1712 lock_sock(sk); 1713 1714 ssock = __mptcp_nmpc_socket(msk); 1715 if (unlikely(ssock && (inet_sk(ssock->sk)->defer_connect || 1716 msg->msg_flags & MSG_FASTOPEN))) { 1717 int copied_syn = 0; 1718 1719 ret = mptcp_sendmsg_fastopen(sk, ssock->sk, msg, len, &copied_syn); 1720 copied += copied_syn; 1721 if (ret == -EINPROGRESS && copied_syn > 0) 1722 goto out; 1723 else if (ret) 1724 goto do_error; 1725 } 1726 1727 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1728 1729 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 1730 ret = sk_stream_wait_connect(sk, &timeo); 1731 if (ret) 1732 goto do_error; 1733 } 1734 1735 ret = -EPIPE; 1736 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))) 1737 goto do_error; 1738 1739 pfrag = sk_page_frag(sk); 1740 1741 while (msg_data_left(msg)) { 1742 int total_ts, frag_truesize = 0; 1743 struct mptcp_data_frag *dfrag; 1744 bool dfrag_collapsed; 1745 size_t psize, offset; 1746 1747 /* reuse tail pfrag, if possible, or carve a new one from the 1748 * page allocator 1749 */ 1750 dfrag = mptcp_pending_tail(sk); 1751 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 1752 if (!dfrag_collapsed) { 1753 if (!sk_stream_memory_free(sk)) 1754 goto wait_for_memory; 1755 1756 if (!mptcp_page_frag_refill(sk, pfrag)) 1757 goto wait_for_memory; 1758 1759 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); 1760 frag_truesize = dfrag->overhead; 1761 } 1762 1763 /* we do not bound vs wspace, to allow a single packet. 1764 * memory accounting will prevent execessive memory usage 1765 * anyway 1766 */ 1767 offset = dfrag->offset + dfrag->data_len; 1768 psize = pfrag->size - offset; 1769 psize = min_t(size_t, psize, msg_data_left(msg)); 1770 total_ts = psize + frag_truesize; 1771 1772 if (!sk_wmem_schedule(sk, total_ts)) 1773 goto wait_for_memory; 1774 1775 if (copy_page_from_iter(dfrag->page, offset, psize, 1776 &msg->msg_iter) != psize) { 1777 ret = -EFAULT; 1778 goto do_error; 1779 } 1780 1781 /* data successfully copied into the write queue */ 1782 sk->sk_forward_alloc -= total_ts; 1783 copied += psize; 1784 dfrag->data_len += psize; 1785 frag_truesize += psize; 1786 pfrag->offset += frag_truesize; 1787 WRITE_ONCE(msk->write_seq, msk->write_seq + psize); 1788 1789 /* charge data on mptcp pending queue to the msk socket 1790 * Note: we charge such data both to sk and ssk 1791 */ 1792 sk_wmem_queued_add(sk, frag_truesize); 1793 if (!dfrag_collapsed) { 1794 get_page(dfrag->page); 1795 list_add_tail(&dfrag->list, &msk->rtx_queue); 1796 if (!msk->first_pending) 1797 WRITE_ONCE(msk->first_pending, dfrag); 1798 } 1799 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, 1800 dfrag->data_seq, dfrag->data_len, dfrag->already_sent, 1801 !dfrag_collapsed); 1802 1803 continue; 1804 1805 wait_for_memory: 1806 mptcp_set_nospace(sk); 1807 __mptcp_push_pending(sk, msg->msg_flags); 1808 ret = sk_stream_wait_memory(sk, &timeo); 1809 if (ret) 1810 goto do_error; 1811 } 1812 1813 if (copied) 1814 __mptcp_push_pending(sk, msg->msg_flags); 1815 1816 out: 1817 release_sock(sk); 1818 return copied; 1819 1820 do_error: 1821 if (copied) 1822 goto out; 1823 1824 copied = sk_stream_error(sk, msg->msg_flags, ret); 1825 goto out; 1826 } 1827 1828 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1829 struct msghdr *msg, 1830 size_t len, int flags, 1831 struct scm_timestamping_internal *tss, 1832 int *cmsg_flags) 1833 { 1834 struct sk_buff *skb, *tmp; 1835 int copied = 0; 1836 1837 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { 1838 u32 offset = MPTCP_SKB_CB(skb)->offset; 1839 u32 data_len = skb->len - offset; 1840 u32 count = min_t(size_t, len - copied, data_len); 1841 int err; 1842 1843 if (!(flags & MSG_TRUNC)) { 1844 err = skb_copy_datagram_msg(skb, offset, msg, count); 1845 if (unlikely(err < 0)) { 1846 if (!copied) 1847 return err; 1848 break; 1849 } 1850 } 1851 1852 if (MPTCP_SKB_CB(skb)->has_rxtstamp) { 1853 tcp_update_recv_tstamps(skb, tss); 1854 *cmsg_flags |= MPTCP_CMSG_TS; 1855 } 1856 1857 copied += count; 1858 1859 if (count < data_len) { 1860 if (!(flags & MSG_PEEK)) { 1861 MPTCP_SKB_CB(skb)->offset += count; 1862 MPTCP_SKB_CB(skb)->map_seq += count; 1863 } 1864 break; 1865 } 1866 1867 if (!(flags & MSG_PEEK)) { 1868 /* we will bulk release the skb memory later */ 1869 skb->destructor = NULL; 1870 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); 1871 __skb_unlink(skb, &msk->receive_queue); 1872 __kfree_skb(skb); 1873 } 1874 1875 if (copied >= len) 1876 break; 1877 } 1878 1879 return copied; 1880 } 1881 1882 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1883 * 1884 * Only difference: Use highest rtt estimate of the subflows in use. 1885 */ 1886 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1887 { 1888 struct mptcp_subflow_context *subflow; 1889 struct sock *sk = (struct sock *)msk; 1890 u32 time, advmss = 1; 1891 u64 rtt_us, mstamp; 1892 1893 sock_owned_by_me(sk); 1894 1895 if (copied <= 0) 1896 return; 1897 1898 msk->rcvq_space.copied += copied; 1899 1900 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1901 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1902 1903 rtt_us = msk->rcvq_space.rtt_us; 1904 if (rtt_us && time < (rtt_us >> 3)) 1905 return; 1906 1907 rtt_us = 0; 1908 mptcp_for_each_subflow(msk, subflow) { 1909 const struct tcp_sock *tp; 1910 u64 sf_rtt_us; 1911 u32 sf_advmss; 1912 1913 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1914 1915 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1916 sf_advmss = READ_ONCE(tp->advmss); 1917 1918 rtt_us = max(sf_rtt_us, rtt_us); 1919 advmss = max(sf_advmss, advmss); 1920 } 1921 1922 msk->rcvq_space.rtt_us = rtt_us; 1923 if (time < (rtt_us >> 3) || rtt_us == 0) 1924 return; 1925 1926 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 1927 goto new_measure; 1928 1929 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && 1930 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 1931 int rcvmem, rcvbuf; 1932 u64 rcvwin, grow; 1933 1934 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 1935 1936 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 1937 1938 do_div(grow, msk->rcvq_space.space); 1939 rcvwin += (grow << 1); 1940 1941 rcvmem = SKB_TRUESIZE(advmss + MAX_TCP_HEADER); 1942 while (tcp_win_from_space(sk, rcvmem) < advmss) 1943 rcvmem += 128; 1944 1945 do_div(rcvwin, advmss); 1946 rcvbuf = min_t(u64, rcvwin * rcvmem, 1947 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); 1948 1949 if (rcvbuf > sk->sk_rcvbuf) { 1950 u32 window_clamp; 1951 1952 window_clamp = tcp_win_from_space(sk, rcvbuf); 1953 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 1954 1955 /* Make subflows follow along. If we do not do this, we 1956 * get drops at subflow level if skbs can't be moved to 1957 * the mptcp rx queue fast enough (announced rcv_win can 1958 * exceed ssk->sk_rcvbuf). 1959 */ 1960 mptcp_for_each_subflow(msk, subflow) { 1961 struct sock *ssk; 1962 bool slow; 1963 1964 ssk = mptcp_subflow_tcp_sock(subflow); 1965 slow = lock_sock_fast(ssk); 1966 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 1967 tcp_sk(ssk)->window_clamp = window_clamp; 1968 tcp_cleanup_rbuf(ssk, 1); 1969 unlock_sock_fast(ssk, slow); 1970 } 1971 } 1972 } 1973 1974 msk->rcvq_space.space = msk->rcvq_space.copied; 1975 new_measure: 1976 msk->rcvq_space.copied = 0; 1977 msk->rcvq_space.time = mstamp; 1978 } 1979 1980 static void __mptcp_update_rmem(struct sock *sk) 1981 { 1982 struct mptcp_sock *msk = mptcp_sk(sk); 1983 1984 if (!msk->rmem_released) 1985 return; 1986 1987 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); 1988 mptcp_rmem_uncharge(sk, msk->rmem_released); 1989 WRITE_ONCE(msk->rmem_released, 0); 1990 } 1991 1992 static void __mptcp_splice_receive_queue(struct sock *sk) 1993 { 1994 struct mptcp_sock *msk = mptcp_sk(sk); 1995 1996 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); 1997 } 1998 1999 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 2000 { 2001 struct sock *sk = (struct sock *)msk; 2002 unsigned int moved = 0; 2003 bool ret, done; 2004 2005 do { 2006 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 2007 bool slowpath; 2008 2009 /* we can have data pending in the subflows only if the msk 2010 * receive buffer was full at subflow_data_ready() time, 2011 * that is an unlikely slow path. 2012 */ 2013 if (likely(!ssk)) 2014 break; 2015 2016 slowpath = lock_sock_fast(ssk); 2017 mptcp_data_lock(sk); 2018 __mptcp_update_rmem(sk); 2019 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 2020 mptcp_data_unlock(sk); 2021 2022 if (unlikely(ssk->sk_err)) 2023 __mptcp_error_report(sk); 2024 unlock_sock_fast(ssk, slowpath); 2025 } while (!done); 2026 2027 /* acquire the data lock only if some input data is pending */ 2028 ret = moved > 0; 2029 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || 2030 !skb_queue_empty_lockless(&sk->sk_receive_queue)) { 2031 mptcp_data_lock(sk); 2032 __mptcp_update_rmem(sk); 2033 ret |= __mptcp_ofo_queue(msk); 2034 __mptcp_splice_receive_queue(sk); 2035 mptcp_data_unlock(sk); 2036 } 2037 if (ret) 2038 mptcp_check_data_fin((struct sock *)msk); 2039 return !skb_queue_empty(&msk->receive_queue); 2040 } 2041 2042 static unsigned int mptcp_inq_hint(const struct sock *sk) 2043 { 2044 const struct mptcp_sock *msk = mptcp_sk(sk); 2045 const struct sk_buff *skb; 2046 2047 skb = skb_peek(&msk->receive_queue); 2048 if (skb) { 2049 u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 2050 2051 if (hint_val >= INT_MAX) 2052 return INT_MAX; 2053 2054 return (unsigned int)hint_val; 2055 } 2056 2057 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 2058 return 1; 2059 2060 return 0; 2061 } 2062 2063 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 2064 int flags, int *addr_len) 2065 { 2066 struct mptcp_sock *msk = mptcp_sk(sk); 2067 struct scm_timestamping_internal tss; 2068 int copied = 0, cmsg_flags = 0; 2069 int target; 2070 long timeo; 2071 2072 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ 2073 if (unlikely(flags & MSG_ERRQUEUE)) 2074 return inet_recv_error(sk, msg, len, addr_len); 2075 2076 lock_sock(sk); 2077 if (unlikely(sk->sk_state == TCP_LISTEN)) { 2078 copied = -ENOTCONN; 2079 goto out_err; 2080 } 2081 2082 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 2083 2084 len = min_t(size_t, len, INT_MAX); 2085 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 2086 2087 if (unlikely(msk->recvmsg_inq)) 2088 cmsg_flags = MPTCP_CMSG_INQ; 2089 2090 while (copied < len) { 2091 int bytes_read; 2092 2093 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); 2094 if (unlikely(bytes_read < 0)) { 2095 if (!copied) 2096 copied = bytes_read; 2097 goto out_err; 2098 } 2099 2100 copied += bytes_read; 2101 2102 /* be sure to advertise window change */ 2103 mptcp_cleanup_rbuf(msk); 2104 2105 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) 2106 continue; 2107 2108 /* only the master socket status is relevant here. The exit 2109 * conditions mirror closely tcp_recvmsg() 2110 */ 2111 if (copied >= target) 2112 break; 2113 2114 if (copied) { 2115 if (sk->sk_err || 2116 sk->sk_state == TCP_CLOSE || 2117 (sk->sk_shutdown & RCV_SHUTDOWN) || 2118 !timeo || 2119 signal_pending(current)) 2120 break; 2121 } else { 2122 if (sk->sk_err) { 2123 copied = sock_error(sk); 2124 break; 2125 } 2126 2127 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2128 mptcp_check_for_eof(msk); 2129 2130 if (sk->sk_shutdown & RCV_SHUTDOWN) { 2131 /* race breaker: the shutdown could be after the 2132 * previous receive queue check 2133 */ 2134 if (__mptcp_move_skbs(msk)) 2135 continue; 2136 break; 2137 } 2138 2139 if (sk->sk_state == TCP_CLOSE) { 2140 copied = -ENOTCONN; 2141 break; 2142 } 2143 2144 if (!timeo) { 2145 copied = -EAGAIN; 2146 break; 2147 } 2148 2149 if (signal_pending(current)) { 2150 copied = sock_intr_errno(timeo); 2151 break; 2152 } 2153 } 2154 2155 pr_debug("block timeout %ld", timeo); 2156 sk_wait_data(sk, &timeo, NULL); 2157 } 2158 2159 out_err: 2160 if (cmsg_flags && copied >= 0) { 2161 if (cmsg_flags & MPTCP_CMSG_TS) 2162 tcp_recv_timestamp(msg, sk, &tss); 2163 2164 if (cmsg_flags & MPTCP_CMSG_INQ) { 2165 unsigned int inq = mptcp_inq_hint(sk); 2166 2167 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq); 2168 } 2169 } 2170 2171 pr_debug("msk=%p rx queue empty=%d:%d copied=%d", 2172 msk, skb_queue_empty_lockless(&sk->sk_receive_queue), 2173 skb_queue_empty(&msk->receive_queue), copied); 2174 if (!(flags & MSG_PEEK)) 2175 mptcp_rcv_space_adjust(msk, copied); 2176 2177 release_sock(sk); 2178 return copied; 2179 } 2180 2181 static void mptcp_retransmit_timer(struct timer_list *t) 2182 { 2183 struct inet_connection_sock *icsk = from_timer(icsk, t, 2184 icsk_retransmit_timer); 2185 struct sock *sk = &icsk->icsk_inet.sk; 2186 struct mptcp_sock *msk = mptcp_sk(sk); 2187 2188 bh_lock_sock(sk); 2189 if (!sock_owned_by_user(sk)) { 2190 /* we need a process context to retransmit */ 2191 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) 2192 mptcp_schedule_work(sk); 2193 } else { 2194 /* delegate our work to tcp_release_cb() */ 2195 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags); 2196 } 2197 bh_unlock_sock(sk); 2198 sock_put(sk); 2199 } 2200 2201 static void mptcp_timeout_timer(struct timer_list *t) 2202 { 2203 struct sock *sk = from_timer(sk, t, sk_timer); 2204 2205 mptcp_schedule_work(sk); 2206 sock_put(sk); 2207 } 2208 2209 /* Find an idle subflow. Return NULL if there is unacked data at tcp 2210 * level. 2211 * 2212 * A backup subflow is returned only if that is the only kind available. 2213 */ 2214 static struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk) 2215 { 2216 struct sock *backup = NULL, *pick = NULL; 2217 struct mptcp_subflow_context *subflow; 2218 int min_stale_count = INT_MAX; 2219 2220 sock_owned_by_me((const struct sock *)msk); 2221 2222 if (__mptcp_check_fallback(msk)) 2223 return NULL; 2224 2225 mptcp_for_each_subflow(msk, subflow) { 2226 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2227 2228 if (!__mptcp_subflow_active(subflow)) 2229 continue; 2230 2231 /* still data outstanding at TCP level? skip this */ 2232 if (!tcp_rtx_and_write_queues_empty(ssk)) { 2233 mptcp_pm_subflow_chk_stale(msk, ssk); 2234 min_stale_count = min_t(int, min_stale_count, subflow->stale_count); 2235 continue; 2236 } 2237 2238 if (subflow->backup) { 2239 if (!backup) 2240 backup = ssk; 2241 continue; 2242 } 2243 2244 if (!pick) 2245 pick = ssk; 2246 } 2247 2248 if (pick) 2249 return pick; 2250 2251 /* use backup only if there are no progresses anywhere */ 2252 return min_stale_count > 1 ? backup : NULL; 2253 } 2254 2255 static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk) 2256 { 2257 if (msk->subflow) { 2258 iput(SOCK_INODE(msk->subflow)); 2259 msk->subflow = NULL; 2260 } 2261 } 2262 2263 bool __mptcp_retransmit_pending_data(struct sock *sk) 2264 { 2265 struct mptcp_data_frag *cur, *rtx_head; 2266 struct mptcp_sock *msk = mptcp_sk(sk); 2267 2268 if (__mptcp_check_fallback(msk)) 2269 return false; 2270 2271 if (tcp_rtx_and_write_queues_empty(sk)) 2272 return false; 2273 2274 /* the closing socket has some data untransmitted and/or unacked: 2275 * some data in the mptcp rtx queue has not really xmitted yet. 2276 * keep it simple and re-inject the whole mptcp level rtx queue 2277 */ 2278 mptcp_data_lock(sk); 2279 __mptcp_clean_una_wakeup(sk); 2280 rtx_head = mptcp_rtx_head(sk); 2281 if (!rtx_head) { 2282 mptcp_data_unlock(sk); 2283 return false; 2284 } 2285 2286 msk->recovery_snd_nxt = msk->snd_nxt; 2287 msk->recovery = true; 2288 mptcp_data_unlock(sk); 2289 2290 msk->first_pending = rtx_head; 2291 msk->snd_burst = 0; 2292 2293 /* be sure to clear the "sent status" on all re-injected fragments */ 2294 list_for_each_entry(cur, &msk->rtx_queue, list) { 2295 if (!cur->already_sent) 2296 break; 2297 cur->already_sent = 0; 2298 } 2299 2300 return true; 2301 } 2302 2303 /* flags for __mptcp_close_ssk() */ 2304 #define MPTCP_CF_PUSH BIT(1) 2305 #define MPTCP_CF_FASTCLOSE BIT(2) 2306 2307 /* subflow sockets can be either outgoing (connect) or incoming 2308 * (accept). 2309 * 2310 * Outgoing subflows use in-kernel sockets. 2311 * Incoming subflows do not have their own 'struct socket' allocated, 2312 * so we need to use tcp_close() after detaching them from the mptcp 2313 * parent socket. 2314 */ 2315 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2316 struct mptcp_subflow_context *subflow, 2317 unsigned int flags) 2318 { 2319 struct mptcp_sock *msk = mptcp_sk(sk); 2320 bool need_push, dispose_it; 2321 2322 dispose_it = !msk->subflow || ssk != msk->subflow->sk; 2323 if (dispose_it) 2324 list_del(&subflow->node); 2325 2326 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2327 2328 if (flags & MPTCP_CF_FASTCLOSE) { 2329 /* be sure to force the tcp_disconnect() path, 2330 * to generate the egress reset 2331 */ 2332 ssk->sk_lingertime = 0; 2333 sock_set_flag(ssk, SOCK_LINGER); 2334 subflow->send_fastclose = 1; 2335 } 2336 2337 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); 2338 if (!dispose_it) { 2339 tcp_disconnect(ssk, 0); 2340 msk->subflow->state = SS_UNCONNECTED; 2341 mptcp_subflow_ctx_reset(subflow); 2342 release_sock(ssk); 2343 2344 goto out; 2345 } 2346 2347 sock_orphan(ssk); 2348 subflow->disposable = 1; 2349 2350 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops 2351 * the ssk has been already destroyed, we just need to release the 2352 * reference owned by msk; 2353 */ 2354 if (!inet_csk(ssk)->icsk_ulp_ops) { 2355 kfree_rcu(subflow, rcu); 2356 } else { 2357 /* otherwise tcp will dispose of the ssk and subflow ctx */ 2358 if (ssk->sk_state == TCP_LISTEN) { 2359 tcp_set_state(ssk, TCP_CLOSE); 2360 mptcp_subflow_queue_clean(sk, ssk); 2361 inet_csk_listen_stop(ssk); 2362 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED); 2363 } 2364 __tcp_close(ssk, 0); 2365 2366 /* close acquired an extra ref */ 2367 __sock_put(ssk); 2368 } 2369 release_sock(ssk); 2370 2371 sock_put(ssk); 2372 2373 if (ssk == msk->first) 2374 msk->first = NULL; 2375 2376 out: 2377 if (ssk == msk->last_snd) 2378 msk->last_snd = NULL; 2379 2380 if (need_push) 2381 __mptcp_push_pending(sk, 0); 2382 } 2383 2384 void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2385 struct mptcp_subflow_context *subflow) 2386 { 2387 if (sk->sk_state == TCP_ESTABLISHED) 2388 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); 2389 2390 /* subflow aborted before reaching the fully_established status 2391 * attempt the creation of the next subflow 2392 */ 2393 mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow); 2394 2395 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH); 2396 } 2397 2398 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 2399 { 2400 return 0; 2401 } 2402 2403 static void __mptcp_close_subflow(struct mptcp_sock *msk) 2404 { 2405 struct mptcp_subflow_context *subflow, *tmp; 2406 2407 might_sleep(); 2408 2409 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2410 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2411 2412 if (inet_sk_state_load(ssk) != TCP_CLOSE) 2413 continue; 2414 2415 /* 'subflow_data_ready' will re-sched once rx queue is empty */ 2416 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) 2417 continue; 2418 2419 mptcp_close_ssk((struct sock *)msk, ssk, subflow); 2420 } 2421 } 2422 2423 static bool mptcp_check_close_timeout(const struct sock *sk) 2424 { 2425 s32 delta = tcp_jiffies32 - inet_csk(sk)->icsk_mtup.probe_timestamp; 2426 struct mptcp_subflow_context *subflow; 2427 2428 if (delta >= TCP_TIMEWAIT_LEN) 2429 return true; 2430 2431 /* if all subflows are in closed status don't bother with additional 2432 * timeout 2433 */ 2434 mptcp_for_each_subflow(mptcp_sk(sk), subflow) { 2435 if (inet_sk_state_load(mptcp_subflow_tcp_sock(subflow)) != 2436 TCP_CLOSE) 2437 return false; 2438 } 2439 return true; 2440 } 2441 2442 static void mptcp_check_fastclose(struct mptcp_sock *msk) 2443 { 2444 struct mptcp_subflow_context *subflow, *tmp; 2445 struct sock *sk = (struct sock *)msk; 2446 2447 if (likely(!READ_ONCE(msk->rcv_fastclose))) 2448 return; 2449 2450 mptcp_token_destroy(msk); 2451 2452 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2453 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2454 bool slow; 2455 2456 slow = lock_sock_fast(tcp_sk); 2457 if (tcp_sk->sk_state != TCP_CLOSE) { 2458 tcp_send_active_reset(tcp_sk, GFP_ATOMIC); 2459 tcp_set_state(tcp_sk, TCP_CLOSE); 2460 } 2461 unlock_sock_fast(tcp_sk, slow); 2462 } 2463 2464 /* Mirror the tcp_reset() error propagation */ 2465 switch (sk->sk_state) { 2466 case TCP_SYN_SENT: 2467 sk->sk_err = ECONNREFUSED; 2468 break; 2469 case TCP_CLOSE_WAIT: 2470 sk->sk_err = EPIPE; 2471 break; 2472 case TCP_CLOSE: 2473 return; 2474 default: 2475 sk->sk_err = ECONNRESET; 2476 } 2477 2478 inet_sk_state_store(sk, TCP_CLOSE); 2479 sk->sk_shutdown = SHUTDOWN_MASK; 2480 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 2481 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); 2482 2483 /* the calling mptcp_worker will properly destroy the socket */ 2484 if (sock_flag(sk, SOCK_DEAD)) 2485 return; 2486 2487 sk->sk_state_change(sk); 2488 sk_error_report(sk); 2489 } 2490 2491 static void __mptcp_retrans(struct sock *sk) 2492 { 2493 struct mptcp_sock *msk = mptcp_sk(sk); 2494 struct mptcp_sendmsg_info info = {}; 2495 struct mptcp_data_frag *dfrag; 2496 size_t copied = 0; 2497 struct sock *ssk; 2498 int ret; 2499 2500 mptcp_clean_una_wakeup(sk); 2501 2502 /* first check ssk: need to kick "stale" logic */ 2503 ssk = mptcp_subflow_get_retrans(msk); 2504 dfrag = mptcp_rtx_head(sk); 2505 if (!dfrag) { 2506 if (mptcp_data_fin_enabled(msk)) { 2507 struct inet_connection_sock *icsk = inet_csk(sk); 2508 2509 icsk->icsk_retransmits++; 2510 mptcp_set_datafin_timeout(sk); 2511 mptcp_send_ack(msk); 2512 2513 goto reset_timer; 2514 } 2515 2516 if (!mptcp_send_head(sk)) 2517 return; 2518 2519 goto reset_timer; 2520 } 2521 2522 if (!ssk) 2523 goto reset_timer; 2524 2525 lock_sock(ssk); 2526 2527 /* limit retransmission to the bytes already sent on some subflows */ 2528 info.sent = 0; 2529 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : dfrag->already_sent; 2530 while (info.sent < info.limit) { 2531 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 2532 if (ret <= 0) 2533 break; 2534 2535 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 2536 copied += ret; 2537 info.sent += ret; 2538 } 2539 if (copied) { 2540 dfrag->already_sent = max(dfrag->already_sent, info.sent); 2541 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 2542 info.size_goal); 2543 WRITE_ONCE(msk->allow_infinite_fallback, false); 2544 } 2545 2546 release_sock(ssk); 2547 2548 reset_timer: 2549 mptcp_check_and_set_pending(sk); 2550 2551 if (!mptcp_timer_pending(sk)) 2552 mptcp_reset_timer(sk); 2553 } 2554 2555 /* schedule the timeout timer for the relevant event: either close timeout 2556 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one 2557 */ 2558 void mptcp_reset_timeout(struct mptcp_sock *msk, unsigned long fail_tout) 2559 { 2560 struct sock *sk = (struct sock *)msk; 2561 unsigned long timeout, close_timeout; 2562 2563 if (!fail_tout && !sock_flag(sk, SOCK_DEAD)) 2564 return; 2565 2566 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + TCP_TIMEWAIT_LEN; 2567 2568 /* the close timeout takes precedence on the fail one, and here at least one of 2569 * them is active 2570 */ 2571 timeout = sock_flag(sk, SOCK_DEAD) ? close_timeout : fail_tout; 2572 2573 sk_reset_timer(sk, &sk->sk_timer, timeout); 2574 } 2575 2576 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) 2577 { 2578 struct sock *ssk = msk->first; 2579 bool slow; 2580 2581 if (!ssk) 2582 return; 2583 2584 pr_debug("MP_FAIL doesn't respond, reset the subflow"); 2585 2586 slow = lock_sock_fast(ssk); 2587 mptcp_subflow_reset(ssk); 2588 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0); 2589 unlock_sock_fast(ssk, slow); 2590 2591 mptcp_reset_timeout(msk, 0); 2592 } 2593 2594 static void mptcp_do_fastclose(struct sock *sk) 2595 { 2596 struct mptcp_subflow_context *subflow, *tmp; 2597 struct mptcp_sock *msk = mptcp_sk(sk); 2598 2599 mptcp_for_each_subflow_safe(msk, subflow, tmp) 2600 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), 2601 subflow, MPTCP_CF_FASTCLOSE); 2602 } 2603 2604 static void mptcp_worker(struct work_struct *work) 2605 { 2606 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 2607 struct sock *sk = (struct sock *)msk; 2608 unsigned long fail_tout; 2609 int state; 2610 2611 lock_sock(sk); 2612 state = sk->sk_state; 2613 if (unlikely(state == TCP_CLOSE)) 2614 goto unlock; 2615 2616 mptcp_check_data_fin_ack(sk); 2617 2618 mptcp_check_fastclose(msk); 2619 2620 mptcp_pm_nl_work(msk); 2621 2622 if (test_and_clear_bit(MPTCP_WORK_EOF, &msk->flags)) 2623 mptcp_check_for_eof(msk); 2624 2625 __mptcp_check_send_data_fin(sk); 2626 mptcp_check_data_fin(sk); 2627 2628 /* There is no point in keeping around an orphaned sk timedout or 2629 * closed, but we need the msk around to reply to incoming DATA_FIN, 2630 * even if it is orphaned and in FIN_WAIT2 state 2631 */ 2632 if (sock_flag(sk, SOCK_DEAD)) { 2633 if (mptcp_check_close_timeout(sk)) { 2634 inet_sk_state_store(sk, TCP_CLOSE); 2635 mptcp_do_fastclose(sk); 2636 } 2637 if (sk->sk_state == TCP_CLOSE) { 2638 __mptcp_destroy_sock(sk); 2639 goto unlock; 2640 } 2641 } 2642 2643 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) 2644 __mptcp_close_subflow(msk); 2645 2646 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 2647 __mptcp_retrans(sk); 2648 2649 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0; 2650 if (fail_tout && time_after(jiffies, fail_tout)) 2651 mptcp_mp_fail_no_response(msk); 2652 2653 unlock: 2654 release_sock(sk); 2655 sock_put(sk); 2656 } 2657 2658 static int __mptcp_init_sock(struct sock *sk) 2659 { 2660 struct mptcp_sock *msk = mptcp_sk(sk); 2661 2662 INIT_LIST_HEAD(&msk->conn_list); 2663 INIT_LIST_HEAD(&msk->join_list); 2664 INIT_LIST_HEAD(&msk->rtx_queue); 2665 INIT_WORK(&msk->work, mptcp_worker); 2666 __skb_queue_head_init(&msk->receive_queue); 2667 msk->out_of_order_queue = RB_ROOT; 2668 msk->first_pending = NULL; 2669 msk->rmem_fwd_alloc = 0; 2670 WRITE_ONCE(msk->rmem_released, 0); 2671 msk->timer_ival = TCP_RTO_MIN; 2672 2673 msk->first = NULL; 2674 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 2675 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 2676 WRITE_ONCE(msk->allow_infinite_fallback, true); 2677 msk->recovery = false; 2678 2679 mptcp_pm_data_init(msk); 2680 2681 /* re-use the csk retrans timer for MPTCP-level retrans */ 2682 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 2683 timer_setup(&sk->sk_timer, mptcp_timeout_timer, 0); 2684 2685 return 0; 2686 } 2687 2688 static void mptcp_ca_reset(struct sock *sk) 2689 { 2690 struct inet_connection_sock *icsk = inet_csk(sk); 2691 2692 tcp_assign_congestion_control(sk); 2693 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); 2694 2695 /* no need to keep a reference to the ops, the name will suffice */ 2696 tcp_cleanup_congestion_control(sk); 2697 icsk->icsk_ca_ops = NULL; 2698 } 2699 2700 static int mptcp_init_sock(struct sock *sk) 2701 { 2702 struct net *net = sock_net(sk); 2703 int ret; 2704 2705 ret = __mptcp_init_sock(sk); 2706 if (ret) 2707 return ret; 2708 2709 if (!mptcp_is_enabled(net)) 2710 return -ENOPROTOOPT; 2711 2712 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 2713 return -ENOMEM; 2714 2715 ret = __mptcp_socket_create(mptcp_sk(sk)); 2716 if (ret) 2717 return ret; 2718 2719 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); 2720 2721 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will 2722 * propagate the correct value 2723 */ 2724 mptcp_ca_reset(sk); 2725 2726 sk_sockets_allocated_inc(sk); 2727 sk->sk_rcvbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1]); 2728 sk->sk_sndbuf = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1]); 2729 2730 return 0; 2731 } 2732 2733 static void __mptcp_clear_xmit(struct sock *sk) 2734 { 2735 struct mptcp_sock *msk = mptcp_sk(sk); 2736 struct mptcp_data_frag *dtmp, *dfrag; 2737 2738 WRITE_ONCE(msk->first_pending, NULL); 2739 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 2740 dfrag_clear(sk, dfrag); 2741 } 2742 2743 void mptcp_cancel_work(struct sock *sk) 2744 { 2745 struct mptcp_sock *msk = mptcp_sk(sk); 2746 2747 if (cancel_work_sync(&msk->work)) 2748 __sock_put(sk); 2749 } 2750 2751 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 2752 { 2753 lock_sock(ssk); 2754 2755 switch (ssk->sk_state) { 2756 case TCP_LISTEN: 2757 if (!(how & RCV_SHUTDOWN)) 2758 break; 2759 fallthrough; 2760 case TCP_SYN_SENT: 2761 tcp_disconnect(ssk, O_NONBLOCK); 2762 break; 2763 default: 2764 if (__mptcp_check_fallback(mptcp_sk(sk))) { 2765 pr_debug("Fallback"); 2766 ssk->sk_shutdown |= how; 2767 tcp_shutdown(ssk, how); 2768 } else { 2769 pr_debug("Sending DATA_FIN on subflow %p", ssk); 2770 tcp_send_ack(ssk); 2771 if (!mptcp_timer_pending(sk)) 2772 mptcp_reset_timer(sk); 2773 } 2774 break; 2775 } 2776 2777 release_sock(ssk); 2778 } 2779 2780 static const unsigned char new_state[16] = { 2781 /* current state: new state: action: */ 2782 [0 /* (Invalid) */] = TCP_CLOSE, 2783 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2784 [TCP_SYN_SENT] = TCP_CLOSE, 2785 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2786 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 2787 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 2788 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 2789 [TCP_CLOSE] = TCP_CLOSE, 2790 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 2791 [TCP_LAST_ACK] = TCP_LAST_ACK, 2792 [TCP_LISTEN] = TCP_CLOSE, 2793 [TCP_CLOSING] = TCP_CLOSING, 2794 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 2795 }; 2796 2797 static int mptcp_close_state(struct sock *sk) 2798 { 2799 int next = (int)new_state[sk->sk_state]; 2800 int ns = next & TCP_STATE_MASK; 2801 2802 inet_sk_state_store(sk, ns); 2803 2804 return next & TCP_ACTION_FIN; 2805 } 2806 2807 static void __mptcp_check_send_data_fin(struct sock *sk) 2808 { 2809 struct mptcp_subflow_context *subflow; 2810 struct mptcp_sock *msk = mptcp_sk(sk); 2811 2812 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", 2813 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), 2814 msk->snd_nxt, msk->write_seq); 2815 2816 /* we still need to enqueue subflows or not really shutting down, 2817 * skip this 2818 */ 2819 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || 2820 mptcp_send_head(sk)) 2821 return; 2822 2823 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2824 2825 /* fallback socket will not get data_fin/ack, can move to the next 2826 * state now 2827 */ 2828 if (__mptcp_check_fallback(msk)) { 2829 WRITE_ONCE(msk->snd_una, msk->write_seq); 2830 if ((1 << sk->sk_state) & (TCPF_CLOSING | TCPF_LAST_ACK)) { 2831 inet_sk_state_store(sk, TCP_CLOSE); 2832 mptcp_close_wake_up(sk); 2833 } else if (sk->sk_state == TCP_FIN_WAIT1) { 2834 inet_sk_state_store(sk, TCP_FIN_WAIT2); 2835 } 2836 } 2837 2838 mptcp_for_each_subflow(msk, subflow) { 2839 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2840 2841 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); 2842 } 2843 } 2844 2845 static void __mptcp_wr_shutdown(struct sock *sk) 2846 { 2847 struct mptcp_sock *msk = mptcp_sk(sk); 2848 2849 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", 2850 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, 2851 !!mptcp_send_head(sk)); 2852 2853 /* will be ignored by fallback sockets */ 2854 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2855 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2856 2857 __mptcp_check_send_data_fin(sk); 2858 } 2859 2860 static void __mptcp_destroy_sock(struct sock *sk) 2861 { 2862 struct mptcp_sock *msk = mptcp_sk(sk); 2863 2864 pr_debug("msk=%p", msk); 2865 2866 might_sleep(); 2867 2868 mptcp_stop_timer(sk); 2869 sk_stop_timer(sk, &sk->sk_timer); 2870 msk->pm.status = 0; 2871 2872 sk->sk_prot->destroy(sk); 2873 2874 WARN_ON_ONCE(msk->rmem_fwd_alloc); 2875 WARN_ON_ONCE(msk->rmem_released); 2876 sk_stream_kill_queues(sk); 2877 xfrm_sk_free_policy(sk); 2878 2879 sk_refcnt_debug_release(sk); 2880 sock_put(sk); 2881 } 2882 2883 static __poll_t mptcp_check_readable(struct mptcp_sock *msk) 2884 { 2885 /* Concurrent splices from sk_receive_queue into receive_queue will 2886 * always show at least one non-empty queue when checked in this order. 2887 */ 2888 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && 2889 skb_queue_empty_lockless(&msk->receive_queue)) 2890 return 0; 2891 2892 return EPOLLIN | EPOLLRDNORM; 2893 } 2894 2895 bool __mptcp_close(struct sock *sk, long timeout) 2896 { 2897 struct mptcp_subflow_context *subflow; 2898 struct mptcp_sock *msk = mptcp_sk(sk); 2899 bool do_cancel_work = false; 2900 2901 sk->sk_shutdown = SHUTDOWN_MASK; 2902 2903 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { 2904 inet_sk_state_store(sk, TCP_CLOSE); 2905 goto cleanup; 2906 } 2907 2908 if (mptcp_check_readable(msk)) { 2909 /* the msk has read data, do the MPTCP equivalent of TCP reset */ 2910 inet_sk_state_store(sk, TCP_CLOSE); 2911 mptcp_do_fastclose(sk); 2912 } else if (mptcp_close_state(sk)) { 2913 __mptcp_wr_shutdown(sk); 2914 } 2915 2916 sk_stream_wait_close(sk, timeout); 2917 2918 cleanup: 2919 /* orphan all the subflows */ 2920 inet_csk(sk)->icsk_mtup.probe_timestamp = tcp_jiffies32; 2921 mptcp_for_each_subflow(msk, subflow) { 2922 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2923 bool slow = lock_sock_fast_nested(ssk); 2924 2925 /* since the close timeout takes precedence on the fail one, 2926 * cancel the latter 2927 */ 2928 if (ssk == msk->first) 2929 subflow->fail_tout = 0; 2930 2931 /* detach from the parent socket, but allow data_ready to 2932 * push incoming data into the mptcp stack, to properly ack it 2933 */ 2934 ssk->sk_socket = NULL; 2935 ssk->sk_wq = NULL; 2936 unlock_sock_fast(ssk, slow); 2937 } 2938 sock_orphan(sk); 2939 2940 sock_hold(sk); 2941 pr_debug("msk=%p state=%d", sk, sk->sk_state); 2942 if (msk->token) 2943 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 2944 2945 if (sk->sk_state == TCP_CLOSE) { 2946 __mptcp_destroy_sock(sk); 2947 do_cancel_work = true; 2948 } else { 2949 mptcp_reset_timeout(msk, 0); 2950 } 2951 2952 return do_cancel_work; 2953 } 2954 2955 static void mptcp_close(struct sock *sk, long timeout) 2956 { 2957 bool do_cancel_work; 2958 2959 lock_sock(sk); 2960 2961 do_cancel_work = __mptcp_close(sk, timeout); 2962 release_sock(sk); 2963 if (do_cancel_work) 2964 mptcp_cancel_work(sk); 2965 2966 sock_put(sk); 2967 } 2968 2969 void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 2970 { 2971 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 2972 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 2973 struct ipv6_pinfo *msk6 = inet6_sk(msk); 2974 2975 msk->sk_v6_daddr = ssk->sk_v6_daddr; 2976 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 2977 2978 if (msk6 && ssk6) { 2979 msk6->saddr = ssk6->saddr; 2980 msk6->flow_label = ssk6->flow_label; 2981 } 2982 #endif 2983 2984 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 2985 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 2986 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 2987 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 2988 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 2989 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 2990 } 2991 2992 static int mptcp_disconnect(struct sock *sk, int flags) 2993 { 2994 struct mptcp_sock *msk = mptcp_sk(sk); 2995 2996 /* We are on the fastopen error path. We can't call straight into the 2997 * subflows cleanup code due to lock nesting (we are already under 2998 * msk->firstsocket lock). Do nothing and leave the cleanup to the 2999 * caller. 3000 */ 3001 if (msk->fastopening) 3002 return 0; 3003 3004 inet_sk_state_store(sk, TCP_CLOSE); 3005 3006 mptcp_stop_timer(sk); 3007 sk_stop_timer(sk, &sk->sk_timer); 3008 3009 if (msk->token) 3010 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 3011 3012 /* msk->subflow is still intact, the following will not free the first 3013 * subflow 3014 */ 3015 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); 3016 msk->last_snd = NULL; 3017 WRITE_ONCE(msk->flags, 0); 3018 msk->cb_flags = 0; 3019 msk->push_pending = 0; 3020 msk->recovery = false; 3021 msk->can_ack = false; 3022 msk->fully_established = false; 3023 msk->rcv_data_fin = false; 3024 msk->snd_data_fin_enable = false; 3025 msk->rcv_fastclose = false; 3026 msk->use_64bit_ack = false; 3027 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 3028 mptcp_pm_data_reset(msk); 3029 mptcp_ca_reset(sk); 3030 3031 sk->sk_shutdown = 0; 3032 sk_error_report(sk); 3033 return 0; 3034 } 3035 3036 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3037 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 3038 { 3039 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 3040 3041 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 3042 } 3043 #endif 3044 3045 struct sock *mptcp_sk_clone(const struct sock *sk, 3046 const struct mptcp_options_received *mp_opt, 3047 struct request_sock *req) 3048 { 3049 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 3050 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 3051 struct mptcp_sock *msk; 3052 3053 if (!nsk) 3054 return NULL; 3055 3056 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3057 if (nsk->sk_family == AF_INET6) 3058 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 3059 #endif 3060 3061 __mptcp_init_sock(nsk); 3062 3063 msk = mptcp_sk(nsk); 3064 msk->local_key = subflow_req->local_key; 3065 msk->token = subflow_req->token; 3066 msk->subflow = NULL; 3067 WRITE_ONCE(msk->fully_established, false); 3068 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) 3069 WRITE_ONCE(msk->csum_enabled, true); 3070 3071 msk->write_seq = subflow_req->idsn + 1; 3072 msk->snd_nxt = msk->write_seq; 3073 msk->snd_una = msk->write_seq; 3074 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; 3075 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; 3076 3077 sock_reset_flag(nsk, SOCK_RCU_FREE); 3078 /* will be fully established after successful MPC subflow creation */ 3079 inet_sk_state_store(nsk, TCP_SYN_RECV); 3080 3081 security_inet_csk_clone(nsk, req); 3082 bh_unlock_sock(nsk); 3083 3084 /* keep a single reference */ 3085 __sock_put(nsk); 3086 return nsk; 3087 } 3088 3089 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 3090 { 3091 const struct tcp_sock *tp = tcp_sk(ssk); 3092 3093 msk->rcvq_space.copied = 0; 3094 msk->rcvq_space.rtt_us = 0; 3095 3096 msk->rcvq_space.time = tp->tcp_mstamp; 3097 3098 /* initial rcv_space offering made to peer */ 3099 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 3100 TCP_INIT_CWND * tp->advmss); 3101 if (msk->rcvq_space.space == 0) 3102 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 3103 3104 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); 3105 } 3106 3107 static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, 3108 bool kern) 3109 { 3110 struct mptcp_sock *msk = mptcp_sk(sk); 3111 struct socket *listener; 3112 struct sock *newsk; 3113 3114 listener = __mptcp_nmpc_socket(msk); 3115 if (WARN_ON_ONCE(!listener)) { 3116 *err = -EINVAL; 3117 return NULL; 3118 } 3119 3120 pr_debug("msk=%p, listener=%p", msk, mptcp_subflow_ctx(listener->sk)); 3121 newsk = inet_csk_accept(listener->sk, flags, err, kern); 3122 if (!newsk) 3123 return NULL; 3124 3125 pr_debug("msk=%p, subflow is mptcp=%d", msk, sk_is_mptcp(newsk)); 3126 if (sk_is_mptcp(newsk)) { 3127 struct mptcp_subflow_context *subflow; 3128 struct sock *new_mptcp_sock; 3129 3130 subflow = mptcp_subflow_ctx(newsk); 3131 new_mptcp_sock = subflow->conn; 3132 3133 /* is_mptcp should be false if subflow->conn is missing, see 3134 * subflow_syn_recv_sock() 3135 */ 3136 if (WARN_ON_ONCE(!new_mptcp_sock)) { 3137 tcp_sk(newsk)->is_mptcp = 0; 3138 goto out; 3139 } 3140 3141 /* acquire the 2nd reference for the owning socket */ 3142 sock_hold(new_mptcp_sock); 3143 newsk = new_mptcp_sock; 3144 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 3145 } else { 3146 MPTCP_INC_STATS(sock_net(sk), 3147 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 3148 } 3149 3150 out: 3151 newsk->sk_kern_sock = kern; 3152 return newsk; 3153 } 3154 3155 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) 3156 { 3157 struct mptcp_subflow_context *subflow, *tmp; 3158 struct sock *sk = (struct sock *)msk; 3159 3160 __mptcp_clear_xmit(sk); 3161 3162 /* join list will be eventually flushed (with rst) at sock lock release time */ 3163 mptcp_for_each_subflow_safe(msk, subflow, tmp) 3164 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); 3165 3166 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ 3167 mptcp_data_lock(sk); 3168 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); 3169 __skb_queue_purge(&sk->sk_receive_queue); 3170 skb_rbtree_purge(&msk->out_of_order_queue); 3171 mptcp_data_unlock(sk); 3172 3173 /* move all the rx fwd alloc into the sk_mem_reclaim_final in 3174 * inet_sock_destruct() will dispose it 3175 */ 3176 sk->sk_forward_alloc += msk->rmem_fwd_alloc; 3177 msk->rmem_fwd_alloc = 0; 3178 mptcp_token_destroy(msk); 3179 mptcp_pm_free_anno_list(msk); 3180 mptcp_free_local_addr_list(msk); 3181 } 3182 3183 static void mptcp_destroy(struct sock *sk) 3184 { 3185 struct mptcp_sock *msk = mptcp_sk(sk); 3186 3187 /* clears msk->subflow, allowing the following to close 3188 * even the initial subflow 3189 */ 3190 mptcp_dispose_initial_subflow(msk); 3191 mptcp_destroy_common(msk, 0); 3192 sk_sockets_allocated_dec(sk); 3193 } 3194 3195 void __mptcp_data_acked(struct sock *sk) 3196 { 3197 if (!sock_owned_by_user(sk)) 3198 __mptcp_clean_una(sk); 3199 else 3200 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags); 3201 3202 if (mptcp_pending_data_fin_ack(sk)) 3203 mptcp_schedule_work(sk); 3204 } 3205 3206 void __mptcp_check_push(struct sock *sk, struct sock *ssk) 3207 { 3208 if (!mptcp_send_head(sk)) 3209 return; 3210 3211 if (!sock_owned_by_user(sk)) 3212 __mptcp_subflow_push_pending(sk, ssk, false); 3213 else 3214 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3215 } 3216 3217 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ 3218 BIT(MPTCP_RETRANSMIT) | \ 3219 BIT(MPTCP_FLUSH_JOIN_LIST)) 3220 3221 /* processes deferred events and flush wmem */ 3222 static void mptcp_release_cb(struct sock *sk) 3223 __must_hold(&sk->sk_lock.slock) 3224 { 3225 struct mptcp_sock *msk = mptcp_sk(sk); 3226 3227 for (;;) { 3228 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) | 3229 msk->push_pending; 3230 if (!flags) 3231 break; 3232 3233 /* the following actions acquire the subflow socket lock 3234 * 3235 * 1) can't be invoked in atomic scope 3236 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX 3237 * datapath acquires the msk socket spinlock while helding 3238 * the subflow socket lock 3239 */ 3240 msk->push_pending = 0; 3241 msk->cb_flags &= ~flags; 3242 spin_unlock_bh(&sk->sk_lock.slock); 3243 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST)) 3244 __mptcp_flush_join_list(sk); 3245 if (flags & BIT(MPTCP_PUSH_PENDING)) 3246 __mptcp_push_pending(sk, 0); 3247 if (flags & BIT(MPTCP_RETRANSMIT)) 3248 __mptcp_retrans(sk); 3249 3250 cond_resched(); 3251 spin_lock_bh(&sk->sk_lock.slock); 3252 } 3253 3254 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags)) 3255 __mptcp_clean_una_wakeup(sk); 3256 if (unlikely(&msk->cb_flags)) { 3257 /* be sure to set the current sk state before tacking actions 3258 * depending on sk_state, that is processing MPTCP_ERROR_REPORT 3259 */ 3260 if (__test_and_clear_bit(MPTCP_CONNECTED, &msk->cb_flags)) 3261 __mptcp_set_connected(sk); 3262 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags)) 3263 __mptcp_error_report(sk); 3264 if (__test_and_clear_bit(MPTCP_RESET_SCHEDULER, &msk->cb_flags)) 3265 msk->last_snd = NULL; 3266 } 3267 3268 __mptcp_update_rmem(sk); 3269 } 3270 3271 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 3272 * TCP can't schedule delack timer before the subflow is fully established. 3273 * MPTCP uses the delack timer to do 3rd ack retransmissions 3274 */ 3275 static void schedule_3rdack_retransmission(struct sock *ssk) 3276 { 3277 struct inet_connection_sock *icsk = inet_csk(ssk); 3278 struct tcp_sock *tp = tcp_sk(ssk); 3279 unsigned long timeout; 3280 3281 if (mptcp_subflow_ctx(ssk)->fully_established) 3282 return; 3283 3284 /* reschedule with a timeout above RTT, as we must look only for drop */ 3285 if (tp->srtt_us) 3286 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1)); 3287 else 3288 timeout = TCP_TIMEOUT_INIT; 3289 timeout += jiffies; 3290 3291 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 3292 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 3293 icsk->icsk_ack.timeout = timeout; 3294 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout); 3295 } 3296 3297 void mptcp_subflow_process_delegated(struct sock *ssk) 3298 { 3299 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3300 struct sock *sk = subflow->conn; 3301 3302 if (test_bit(MPTCP_DELEGATE_SEND, &subflow->delegated_status)) { 3303 mptcp_data_lock(sk); 3304 if (!sock_owned_by_user(sk)) 3305 __mptcp_subflow_push_pending(sk, ssk, true); 3306 else 3307 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3308 mptcp_data_unlock(sk); 3309 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND); 3310 } 3311 if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) { 3312 schedule_3rdack_retransmission(ssk); 3313 mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK); 3314 } 3315 } 3316 3317 static int mptcp_hash(struct sock *sk) 3318 { 3319 /* should never be called, 3320 * we hash the TCP subflows not the master socket 3321 */ 3322 WARN_ON_ONCE(1); 3323 return 0; 3324 } 3325 3326 static void mptcp_unhash(struct sock *sk) 3327 { 3328 /* called from sk_common_release(), but nothing to do here */ 3329 } 3330 3331 static int mptcp_get_port(struct sock *sk, unsigned short snum) 3332 { 3333 struct mptcp_sock *msk = mptcp_sk(sk); 3334 struct socket *ssock; 3335 3336 ssock = __mptcp_nmpc_socket(msk); 3337 pr_debug("msk=%p, subflow=%p", msk, ssock); 3338 if (WARN_ON_ONCE(!ssock)) 3339 return -EINVAL; 3340 3341 return inet_csk_get_port(ssock->sk, snum); 3342 } 3343 3344 void mptcp_finish_connect(struct sock *ssk) 3345 { 3346 struct mptcp_subflow_context *subflow; 3347 struct mptcp_sock *msk; 3348 struct sock *sk; 3349 3350 subflow = mptcp_subflow_ctx(ssk); 3351 sk = subflow->conn; 3352 msk = mptcp_sk(sk); 3353 3354 pr_debug("msk=%p, token=%u", sk, subflow->token); 3355 3356 subflow->map_seq = subflow->iasn; 3357 subflow->map_subflow_seq = 1; 3358 3359 /* the socket is not connected yet, no msk/subflow ops can access/race 3360 * accessing the field below 3361 */ 3362 WRITE_ONCE(msk->local_key, subflow->local_key); 3363 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 3364 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 3365 WRITE_ONCE(msk->snd_una, msk->write_seq); 3366 3367 mptcp_pm_new_connection(msk, ssk, 0); 3368 3369 mptcp_rcv_space_init(msk, ssk); 3370 } 3371 3372 void mptcp_sock_graft(struct sock *sk, struct socket *parent) 3373 { 3374 write_lock_bh(&sk->sk_callback_lock); 3375 rcu_assign_pointer(sk->sk_wq, &parent->wq); 3376 sk_set_socket(sk, parent); 3377 sk->sk_uid = SOCK_INODE(parent)->i_uid; 3378 write_unlock_bh(&sk->sk_callback_lock); 3379 } 3380 3381 bool mptcp_finish_join(struct sock *ssk) 3382 { 3383 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3384 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 3385 struct sock *parent = (void *)msk; 3386 bool ret = true; 3387 3388 pr_debug("msk=%p, subflow=%p", msk, subflow); 3389 3390 /* mptcp socket already closing? */ 3391 if (!mptcp_is_fully_established(parent)) { 3392 subflow->reset_reason = MPTCP_RST_EMPTCP; 3393 return false; 3394 } 3395 3396 if (!list_empty(&subflow->node)) 3397 goto out; 3398 3399 if (!mptcp_pm_allow_new_subflow(msk)) 3400 goto err_prohibited; 3401 3402 /* active connections are already on conn_list. 3403 * If we can't acquire msk socket lock here, let the release callback 3404 * handle it 3405 */ 3406 mptcp_data_lock(parent); 3407 if (!sock_owned_by_user(parent)) { 3408 ret = __mptcp_finish_join(msk, ssk); 3409 if (ret) { 3410 sock_hold(ssk); 3411 list_add_tail(&subflow->node, &msk->conn_list); 3412 } 3413 } else { 3414 sock_hold(ssk); 3415 list_add_tail(&subflow->node, &msk->join_list); 3416 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags); 3417 } 3418 mptcp_data_unlock(parent); 3419 3420 if (!ret) { 3421 err_prohibited: 3422 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3423 return false; 3424 } 3425 3426 subflow->map_seq = READ_ONCE(msk->ack_seq); 3427 WRITE_ONCE(msk->allow_infinite_fallback, false); 3428 3429 out: 3430 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); 3431 return true; 3432 } 3433 3434 static void mptcp_shutdown(struct sock *sk, int how) 3435 { 3436 pr_debug("sk=%p, how=%d", sk, how); 3437 3438 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) 3439 __mptcp_wr_shutdown(sk); 3440 } 3441 3442 static int mptcp_forward_alloc_get(const struct sock *sk) 3443 { 3444 return sk->sk_forward_alloc + mptcp_sk(sk)->rmem_fwd_alloc; 3445 } 3446 3447 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) 3448 { 3449 const struct sock *sk = (void *)msk; 3450 u64 delta; 3451 3452 if (sk->sk_state == TCP_LISTEN) 3453 return -EINVAL; 3454 3455 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 3456 return 0; 3457 3458 delta = msk->write_seq - v; 3459 if (__mptcp_check_fallback(msk) && msk->first) { 3460 struct tcp_sock *tp = tcp_sk(msk->first); 3461 3462 /* the first subflow is disconnected after close - see 3463 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq 3464 * so ignore that status, too. 3465 */ 3466 if (!((1 << msk->first->sk_state) & 3467 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) 3468 delta += READ_ONCE(tp->write_seq) - tp->snd_una; 3469 } 3470 if (delta > INT_MAX) 3471 delta = INT_MAX; 3472 3473 return (int)delta; 3474 } 3475 3476 static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg) 3477 { 3478 struct mptcp_sock *msk = mptcp_sk(sk); 3479 bool slow; 3480 int answ; 3481 3482 switch (cmd) { 3483 case SIOCINQ: 3484 if (sk->sk_state == TCP_LISTEN) 3485 return -EINVAL; 3486 3487 lock_sock(sk); 3488 __mptcp_move_skbs(msk); 3489 answ = mptcp_inq_hint(sk); 3490 release_sock(sk); 3491 break; 3492 case SIOCOUTQ: 3493 slow = lock_sock_fast(sk); 3494 answ = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una)); 3495 unlock_sock_fast(sk, slow); 3496 break; 3497 case SIOCOUTQNSD: 3498 slow = lock_sock_fast(sk); 3499 answ = mptcp_ioctl_outq(msk, msk->snd_nxt); 3500 unlock_sock_fast(sk, slow); 3501 break; 3502 default: 3503 return -ENOIOCTLCMD; 3504 } 3505 3506 return put_user(answ, (int __user *)arg); 3507 } 3508 3509 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 3510 struct mptcp_subflow_context *subflow) 3511 { 3512 subflow->request_mptcp = 0; 3513 __mptcp_do_fallback(msk); 3514 } 3515 3516 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 3517 { 3518 struct mptcp_subflow_context *subflow; 3519 struct mptcp_sock *msk = mptcp_sk(sk); 3520 struct socket *ssock; 3521 int err = -EINVAL; 3522 3523 ssock = __mptcp_nmpc_socket(msk); 3524 if (!ssock) 3525 return -EINVAL; 3526 3527 mptcp_token_destroy(msk); 3528 inet_sk_state_store(sk, TCP_SYN_SENT); 3529 subflow = mptcp_subflow_ctx(ssock->sk); 3530 #ifdef CONFIG_TCP_MD5SIG 3531 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 3532 * TCP option space. 3533 */ 3534 if (rcu_access_pointer(tcp_sk(ssock->sk)->md5sig_info)) 3535 mptcp_subflow_early_fallback(msk, subflow); 3536 #endif 3537 if (subflow->request_mptcp && mptcp_token_new_connect(ssock->sk)) { 3538 MPTCP_INC_STATS(sock_net(ssock->sk), MPTCP_MIB_TOKENFALLBACKINIT); 3539 mptcp_subflow_early_fallback(msk, subflow); 3540 } 3541 if (likely(!__mptcp_check_fallback(msk))) 3542 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE); 3543 3544 /* if reaching here via the fastopen/sendmsg path, the caller already 3545 * acquired the subflow socket lock, too. 3546 */ 3547 if (msk->fastopening) 3548 err = __inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags, 1); 3549 else 3550 err = inet_stream_connect(ssock, uaddr, addr_len, msk->connect_flags); 3551 inet_sk(sk)->defer_connect = inet_sk(ssock->sk)->defer_connect; 3552 3553 /* on successful connect, the msk state will be moved to established by 3554 * subflow_finish_connect() 3555 */ 3556 if (unlikely(err && err != -EINPROGRESS)) { 3557 inet_sk_state_store(sk, inet_sk_state_load(ssock->sk)); 3558 return err; 3559 } 3560 3561 mptcp_copy_inaddrs(sk, ssock->sk); 3562 3563 /* unblocking connect, mptcp-level inet_stream_connect will error out 3564 * without changing the socket state, update it here. 3565 */ 3566 if (err == -EINPROGRESS) 3567 sk->sk_socket->state = ssock->state; 3568 return err; 3569 } 3570 3571 static struct proto mptcp_prot = { 3572 .name = "MPTCP", 3573 .owner = THIS_MODULE, 3574 .init = mptcp_init_sock, 3575 .connect = mptcp_connect, 3576 .disconnect = mptcp_disconnect, 3577 .close = mptcp_close, 3578 .accept = mptcp_accept, 3579 .setsockopt = mptcp_setsockopt, 3580 .getsockopt = mptcp_getsockopt, 3581 .shutdown = mptcp_shutdown, 3582 .destroy = mptcp_destroy, 3583 .sendmsg = mptcp_sendmsg, 3584 .ioctl = mptcp_ioctl, 3585 .recvmsg = mptcp_recvmsg, 3586 .release_cb = mptcp_release_cb, 3587 .hash = mptcp_hash, 3588 .unhash = mptcp_unhash, 3589 .get_port = mptcp_get_port, 3590 .forward_alloc_get = mptcp_forward_alloc_get, 3591 .sockets_allocated = &mptcp_sockets_allocated, 3592 3593 .memory_allocated = &tcp_memory_allocated, 3594 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3595 3596 .memory_pressure = &tcp_memory_pressure, 3597 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3598 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3599 .sysctl_mem = sysctl_tcp_mem, 3600 .obj_size = sizeof(struct mptcp_sock), 3601 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3602 .no_autobind = true, 3603 }; 3604 3605 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 3606 { 3607 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3608 struct socket *ssock; 3609 int err; 3610 3611 lock_sock(sock->sk); 3612 ssock = __mptcp_nmpc_socket(msk); 3613 if (!ssock) { 3614 err = -EINVAL; 3615 goto unlock; 3616 } 3617 3618 err = ssock->ops->bind(ssock, uaddr, addr_len); 3619 if (!err) 3620 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3621 3622 unlock: 3623 release_sock(sock->sk); 3624 return err; 3625 } 3626 3627 static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, 3628 int addr_len, int flags) 3629 { 3630 int ret; 3631 3632 lock_sock(sock->sk); 3633 mptcp_sk(sock->sk)->connect_flags = flags; 3634 ret = __inet_stream_connect(sock, uaddr, addr_len, flags, 0); 3635 release_sock(sock->sk); 3636 return ret; 3637 } 3638 3639 static int mptcp_listen(struct socket *sock, int backlog) 3640 { 3641 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3642 struct socket *ssock; 3643 int err; 3644 3645 pr_debug("msk=%p", msk); 3646 3647 lock_sock(sock->sk); 3648 ssock = __mptcp_nmpc_socket(msk); 3649 if (!ssock) { 3650 err = -EINVAL; 3651 goto unlock; 3652 } 3653 3654 mptcp_token_destroy(msk); 3655 inet_sk_state_store(sock->sk, TCP_LISTEN); 3656 sock_set_flag(sock->sk, SOCK_RCU_FREE); 3657 3658 err = ssock->ops->listen(ssock, backlog); 3659 inet_sk_state_store(sock->sk, inet_sk_state_load(ssock->sk)); 3660 if (!err) 3661 mptcp_copy_inaddrs(sock->sk, ssock->sk); 3662 3663 mptcp_event_pm_listener(ssock->sk, MPTCP_EVENT_LISTENER_CREATED); 3664 3665 unlock: 3666 release_sock(sock->sk); 3667 return err; 3668 } 3669 3670 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 3671 int flags, bool kern) 3672 { 3673 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3674 struct socket *ssock; 3675 int err; 3676 3677 pr_debug("msk=%p", msk); 3678 3679 ssock = __mptcp_nmpc_socket(msk); 3680 if (!ssock) 3681 return -EINVAL; 3682 3683 err = ssock->ops->accept(sock, newsock, flags, kern); 3684 if (err == 0 && !mptcp_is_tcpsk(newsock->sk)) { 3685 struct mptcp_sock *msk = mptcp_sk(newsock->sk); 3686 struct mptcp_subflow_context *subflow; 3687 struct sock *newsk = newsock->sk; 3688 3689 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); 3690 3691 lock_sock(newsk); 3692 3693 /* PM/worker can now acquire the first subflow socket 3694 * lock without racing with listener queue cleanup, 3695 * we can notify it, if needed. 3696 * 3697 * Even if remote has reset the initial subflow by now 3698 * the refcnt is still at least one. 3699 */ 3700 subflow = mptcp_subflow_ctx(msk->first); 3701 list_add(&subflow->node, &msk->conn_list); 3702 sock_hold(msk->first); 3703 if (mptcp_is_fully_established(newsk)) 3704 mptcp_pm_fully_established(msk, msk->first, GFP_KERNEL); 3705 3706 mptcp_rcv_space_init(msk, msk->first); 3707 mptcp_propagate_sndbuf(newsk, msk->first); 3708 3709 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 3710 * This is needed so NOSPACE flag can be set from tcp stack. 3711 */ 3712 mptcp_for_each_subflow(msk, subflow) { 3713 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3714 3715 if (!ssk->sk_socket) 3716 mptcp_sock_graft(ssk, newsock); 3717 } 3718 release_sock(newsk); 3719 } 3720 3721 return err; 3722 } 3723 3724 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) 3725 { 3726 struct sock *sk = (struct sock *)msk; 3727 3728 if (unlikely(sk->sk_shutdown & SEND_SHUTDOWN)) 3729 return EPOLLOUT | EPOLLWRNORM; 3730 3731 if (sk_stream_is_writeable(sk)) 3732 return EPOLLOUT | EPOLLWRNORM; 3733 3734 mptcp_set_nospace(sk); 3735 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 3736 if (sk_stream_is_writeable(sk)) 3737 return EPOLLOUT | EPOLLWRNORM; 3738 3739 return 0; 3740 } 3741 3742 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 3743 struct poll_table_struct *wait) 3744 { 3745 struct sock *sk = sock->sk; 3746 struct mptcp_sock *msk; 3747 __poll_t mask = 0; 3748 int state; 3749 3750 msk = mptcp_sk(sk); 3751 sock_poll_wait(file, sock, wait); 3752 3753 state = inet_sk_state_load(sk); 3754 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); 3755 if (state == TCP_LISTEN) { 3756 if (WARN_ON_ONCE(!msk->subflow || !msk->subflow->sk)) 3757 return 0; 3758 3759 return inet_csk_listen_poll(msk->subflow->sk); 3760 } 3761 3762 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 3763 mask |= mptcp_check_readable(msk); 3764 mask |= mptcp_check_writeable(msk); 3765 } else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) { 3766 /* cf tcp_poll() note about TFO */ 3767 mask |= EPOLLOUT | EPOLLWRNORM; 3768 } 3769 if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) 3770 mask |= EPOLLHUP; 3771 if (sk->sk_shutdown & RCV_SHUTDOWN) 3772 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 3773 3774 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */ 3775 smp_rmb(); 3776 if (sk->sk_err) 3777 mask |= EPOLLERR; 3778 3779 return mask; 3780 } 3781 3782 static const struct proto_ops mptcp_stream_ops = { 3783 .family = PF_INET, 3784 .owner = THIS_MODULE, 3785 .release = inet_release, 3786 .bind = mptcp_bind, 3787 .connect = mptcp_stream_connect, 3788 .socketpair = sock_no_socketpair, 3789 .accept = mptcp_stream_accept, 3790 .getname = inet_getname, 3791 .poll = mptcp_poll, 3792 .ioctl = inet_ioctl, 3793 .gettstamp = sock_gettstamp, 3794 .listen = mptcp_listen, 3795 .shutdown = inet_shutdown, 3796 .setsockopt = sock_common_setsockopt, 3797 .getsockopt = sock_common_getsockopt, 3798 .sendmsg = inet_sendmsg, 3799 .recvmsg = inet_recvmsg, 3800 .mmap = sock_no_mmap, 3801 .sendpage = inet_sendpage, 3802 }; 3803 3804 static struct inet_protosw mptcp_protosw = { 3805 .type = SOCK_STREAM, 3806 .protocol = IPPROTO_MPTCP, 3807 .prot = &mptcp_prot, 3808 .ops = &mptcp_stream_ops, 3809 .flags = INET_PROTOSW_ICSK, 3810 }; 3811 3812 static int mptcp_napi_poll(struct napi_struct *napi, int budget) 3813 { 3814 struct mptcp_delegated_action *delegated; 3815 struct mptcp_subflow_context *subflow; 3816 int work_done = 0; 3817 3818 delegated = container_of(napi, struct mptcp_delegated_action, napi); 3819 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { 3820 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3821 3822 bh_lock_sock_nested(ssk); 3823 if (!sock_owned_by_user(ssk) && 3824 mptcp_subflow_has_delegated_action(subflow)) 3825 mptcp_subflow_process_delegated(ssk); 3826 /* ... elsewhere tcp_release_cb_override already processed 3827 * the action or will do at next release_sock(). 3828 * In both case must dequeue the subflow here - on the same 3829 * CPU that scheduled it. 3830 */ 3831 bh_unlock_sock(ssk); 3832 sock_put(ssk); 3833 3834 if (++work_done == budget) 3835 return budget; 3836 } 3837 3838 /* always provide a 0 'work_done' argument, so that napi_complete_done 3839 * will not try accessing the NULL napi->dev ptr 3840 */ 3841 napi_complete_done(napi, 0); 3842 return work_done; 3843 } 3844 3845 void __init mptcp_proto_init(void) 3846 { 3847 struct mptcp_delegated_action *delegated; 3848 int cpu; 3849 3850 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 3851 3852 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 3853 panic("Failed to allocate MPTCP pcpu counter\n"); 3854 3855 init_dummy_netdev(&mptcp_napi_dev); 3856 for_each_possible_cpu(cpu) { 3857 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); 3858 INIT_LIST_HEAD(&delegated->head); 3859 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi, 3860 mptcp_napi_poll); 3861 napi_enable(&delegated->napi); 3862 } 3863 3864 mptcp_subflow_init(); 3865 mptcp_pm_init(); 3866 mptcp_token_init(); 3867 3868 if (proto_register(&mptcp_prot, 1) != 0) 3869 panic("Failed to register MPTCP proto.\n"); 3870 3871 inet_register_protosw(&mptcp_protosw); 3872 3873 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 3874 } 3875 3876 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3877 static const struct proto_ops mptcp_v6_stream_ops = { 3878 .family = PF_INET6, 3879 .owner = THIS_MODULE, 3880 .release = inet6_release, 3881 .bind = mptcp_bind, 3882 .connect = mptcp_stream_connect, 3883 .socketpair = sock_no_socketpair, 3884 .accept = mptcp_stream_accept, 3885 .getname = inet6_getname, 3886 .poll = mptcp_poll, 3887 .ioctl = inet6_ioctl, 3888 .gettstamp = sock_gettstamp, 3889 .listen = mptcp_listen, 3890 .shutdown = inet_shutdown, 3891 .setsockopt = sock_common_setsockopt, 3892 .getsockopt = sock_common_getsockopt, 3893 .sendmsg = inet6_sendmsg, 3894 .recvmsg = inet6_recvmsg, 3895 .mmap = sock_no_mmap, 3896 .sendpage = inet_sendpage, 3897 #ifdef CONFIG_COMPAT 3898 .compat_ioctl = inet6_compat_ioctl, 3899 #endif 3900 }; 3901 3902 static struct proto mptcp_v6_prot; 3903 3904 static struct inet_protosw mptcp_v6_protosw = { 3905 .type = SOCK_STREAM, 3906 .protocol = IPPROTO_MPTCP, 3907 .prot = &mptcp_v6_prot, 3908 .ops = &mptcp_v6_stream_ops, 3909 .flags = INET_PROTOSW_ICSK, 3910 }; 3911 3912 int __init mptcp_proto_v6_init(void) 3913 { 3914 int err; 3915 3916 mptcp_v6_prot = mptcp_prot; 3917 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 3918 mptcp_v6_prot.slab = NULL; 3919 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 3920 3921 err = proto_register(&mptcp_v6_prot, 1); 3922 if (err) 3923 return err; 3924 3925 err = inet6_register_protosw(&mptcp_v6_protosw); 3926 if (err) 3927 proto_unregister(&mptcp_v6_prot); 3928 3929 return err; 3930 } 3931 #endif 3932