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 /* Returns end sequence number of the receiver's advertised window */ 53 static u64 mptcp_wnd_end(const struct mptcp_sock *msk) 54 { 55 return READ_ONCE(msk->wnd_end); 56 } 57 58 static bool mptcp_is_tcpsk(struct sock *sk) 59 { 60 struct socket *sock = sk->sk_socket; 61 62 if (unlikely(sk->sk_prot == &tcp_prot)) { 63 /* we are being invoked after mptcp_accept() has 64 * accepted a non-mp-capable flow: sk is a tcp_sk, 65 * not an mptcp one. 66 * 67 * Hand the socket over to tcp so all further socket ops 68 * bypass mptcp. 69 */ 70 WRITE_ONCE(sock->ops, &inet_stream_ops); 71 return true; 72 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 73 } else if (unlikely(sk->sk_prot == &tcpv6_prot)) { 74 WRITE_ONCE(sock->ops, &inet6_stream_ops); 75 return true; 76 #endif 77 } 78 79 return false; 80 } 81 82 static int __mptcp_socket_create(struct mptcp_sock *msk) 83 { 84 struct mptcp_subflow_context *subflow; 85 struct sock *sk = (struct sock *)msk; 86 struct socket *ssock; 87 int err; 88 89 err = mptcp_subflow_create_socket(sk, sk->sk_family, &ssock); 90 if (err) 91 return err; 92 93 msk->scaling_ratio = tcp_sk(ssock->sk)->scaling_ratio; 94 WRITE_ONCE(msk->first, ssock->sk); 95 subflow = mptcp_subflow_ctx(ssock->sk); 96 list_add(&subflow->node, &msk->conn_list); 97 sock_hold(ssock->sk); 98 subflow->request_mptcp = 1; 99 subflow->subflow_id = msk->subflow_id++; 100 101 /* This is the first subflow, always with id 0 */ 102 subflow->local_id_valid = 1; 103 mptcp_sock_graft(msk->first, sk->sk_socket); 104 iput(SOCK_INODE(ssock)); 105 106 return 0; 107 } 108 109 /* If the MPC handshake is not started, returns the first subflow, 110 * eventually allocating it. 111 */ 112 struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk) 113 { 114 struct sock *sk = (struct sock *)msk; 115 int ret; 116 117 if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) 118 return ERR_PTR(-EINVAL); 119 120 if (!msk->first) { 121 ret = __mptcp_socket_create(msk); 122 if (ret) 123 return ERR_PTR(ret); 124 125 mptcp_sockopt_sync(msk, msk->first); 126 } 127 128 return msk->first; 129 } 130 131 static void mptcp_drop(struct sock *sk, struct sk_buff *skb) 132 { 133 sk_drops_add(sk, skb); 134 __kfree_skb(skb); 135 } 136 137 static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size) 138 { 139 WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc, 140 mptcp_sk(sk)->rmem_fwd_alloc + size); 141 } 142 143 static void mptcp_rmem_charge(struct sock *sk, int size) 144 { 145 mptcp_rmem_fwd_alloc_add(sk, -size); 146 } 147 148 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, 149 struct sk_buff *from) 150 { 151 bool fragstolen; 152 int delta; 153 154 if (MPTCP_SKB_CB(from)->offset || 155 !skb_try_coalesce(to, from, &fragstolen, &delta)) 156 return false; 157 158 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", 159 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, 160 to->len, MPTCP_SKB_CB(from)->end_seq); 161 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; 162 163 /* note the fwd memory can reach a negative value after accounting 164 * for the delta, but the later skb free will restore a non 165 * negative one 166 */ 167 atomic_add(delta, &sk->sk_rmem_alloc); 168 mptcp_rmem_charge(sk, delta); 169 kfree_skb_partial(from, fragstolen); 170 171 return true; 172 } 173 174 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, 175 struct sk_buff *from) 176 { 177 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) 178 return false; 179 180 return mptcp_try_coalesce((struct sock *)msk, to, from); 181 } 182 183 static void __mptcp_rmem_reclaim(struct sock *sk, int amount) 184 { 185 amount >>= PAGE_SHIFT; 186 mptcp_rmem_charge(sk, amount << PAGE_SHIFT); 187 __sk_mem_reduce_allocated(sk, amount); 188 } 189 190 static void mptcp_rmem_uncharge(struct sock *sk, int size) 191 { 192 struct mptcp_sock *msk = mptcp_sk(sk); 193 int reclaimable; 194 195 mptcp_rmem_fwd_alloc_add(sk, size); 196 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk); 197 198 /* see sk_mem_uncharge() for the rationale behind the following schema */ 199 if (unlikely(reclaimable >= PAGE_SIZE)) 200 __mptcp_rmem_reclaim(sk, reclaimable); 201 } 202 203 static void mptcp_rfree(struct sk_buff *skb) 204 { 205 unsigned int len = skb->truesize; 206 struct sock *sk = skb->sk; 207 208 atomic_sub(len, &sk->sk_rmem_alloc); 209 mptcp_rmem_uncharge(sk, len); 210 } 211 212 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk) 213 { 214 skb_orphan(skb); 215 skb->sk = sk; 216 skb->destructor = mptcp_rfree; 217 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 218 mptcp_rmem_charge(sk, skb->truesize); 219 } 220 221 /* "inspired" by tcp_data_queue_ofo(), main differences: 222 * - use mptcp seqs 223 * - don't cope with sacks 224 */ 225 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) 226 { 227 struct sock *sk = (struct sock *)msk; 228 struct rb_node **p, *parent; 229 u64 seq, end_seq, max_seq; 230 struct sk_buff *skb1; 231 232 seq = MPTCP_SKB_CB(skb)->map_seq; 233 end_seq = MPTCP_SKB_CB(skb)->end_seq; 234 max_seq = atomic64_read(&msk->rcv_wnd_sent); 235 236 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, 237 RB_EMPTY_ROOT(&msk->out_of_order_queue)); 238 if (after64(end_seq, max_seq)) { 239 /* out of window */ 240 mptcp_drop(sk, skb); 241 pr_debug("oow by %lld, rcv_wnd_sent %llu\n", 242 (unsigned long long)end_seq - (unsigned long)max_seq, 243 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent)); 244 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); 245 return; 246 } 247 248 p = &msk->out_of_order_queue.rb_node; 249 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); 250 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { 251 rb_link_node(&skb->rbnode, NULL, p); 252 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 253 msk->ooo_last_skb = skb; 254 goto end; 255 } 256 257 /* with 2 subflows, adding at end of ooo queue is quite likely 258 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. 259 */ 260 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { 261 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 262 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 263 return; 264 } 265 266 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ 267 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { 268 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 269 parent = &msk->ooo_last_skb->rbnode; 270 p = &parent->rb_right; 271 goto insert; 272 } 273 274 /* Find place to insert this segment. Handle overlaps on the way. */ 275 parent = NULL; 276 while (*p) { 277 parent = *p; 278 skb1 = rb_to_skb(parent); 279 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 280 p = &parent->rb_left; 281 continue; 282 } 283 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { 284 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { 285 /* All the bits are present. Drop. */ 286 mptcp_drop(sk, skb); 287 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 288 return; 289 } 290 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 291 /* partial overlap: 292 * | skb | 293 * | skb1 | 294 * continue traversing 295 */ 296 } else { 297 /* skb's seq == skb1's seq and skb covers skb1. 298 * Replace skb1 with skb. 299 */ 300 rb_replace_node(&skb1->rbnode, &skb->rbnode, 301 &msk->out_of_order_queue); 302 mptcp_drop(sk, skb1); 303 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 304 goto merge_right; 305 } 306 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { 307 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 308 return; 309 } 310 p = &parent->rb_right; 311 } 312 313 insert: 314 /* Insert segment into RB tree. */ 315 rb_link_node(&skb->rbnode, parent, p); 316 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 317 318 merge_right: 319 /* Remove other segments covered by skb. */ 320 while ((skb1 = skb_rb_next(skb)) != NULL) { 321 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) 322 break; 323 rb_erase(&skb1->rbnode, &msk->out_of_order_queue); 324 mptcp_drop(sk, skb1); 325 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 326 } 327 /* If there is no skb after us, we are the last_skb ! */ 328 if (!skb1) 329 msk->ooo_last_skb = skb; 330 331 end: 332 skb_condense(skb); 333 mptcp_set_owner_r(skb, sk); 334 } 335 336 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size) 337 { 338 struct mptcp_sock *msk = mptcp_sk(sk); 339 int amt, amount; 340 341 if (size <= msk->rmem_fwd_alloc) 342 return true; 343 344 size -= msk->rmem_fwd_alloc; 345 amt = sk_mem_pages(size); 346 amount = amt << PAGE_SHIFT; 347 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) 348 return false; 349 350 mptcp_rmem_fwd_alloc_add(sk, amount); 351 return true; 352 } 353 354 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 355 struct sk_buff *skb, unsigned int offset, 356 size_t copy_len) 357 { 358 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 359 struct sock *sk = (struct sock *)msk; 360 struct sk_buff *tail; 361 bool has_rxtstamp; 362 363 __skb_unlink(skb, &ssk->sk_receive_queue); 364 365 skb_ext_reset(skb); 366 skb_orphan(skb); 367 368 /* try to fetch required memory from subflow */ 369 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) 370 goto drop; 371 372 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; 373 374 /* the skb map_seq accounts for the skb offset: 375 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq 376 * value 377 */ 378 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); 379 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; 380 MPTCP_SKB_CB(skb)->offset = offset; 381 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; 382 383 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { 384 /* in sequence */ 385 msk->bytes_received += copy_len; 386 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); 387 tail = skb_peek_tail(&sk->sk_receive_queue); 388 if (tail && mptcp_try_coalesce(sk, tail, skb)) 389 return true; 390 391 mptcp_set_owner_r(skb, sk); 392 __skb_queue_tail(&sk->sk_receive_queue, skb); 393 return true; 394 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { 395 mptcp_data_queue_ofo(msk, skb); 396 return false; 397 } 398 399 /* old data, keep it simple and drop the whole pkt, sender 400 * will retransmit as needed, if needed. 401 */ 402 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 403 drop: 404 mptcp_drop(sk, skb); 405 return false; 406 } 407 408 static void mptcp_stop_rtx_timer(struct sock *sk) 409 { 410 struct inet_connection_sock *icsk = inet_csk(sk); 411 412 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 413 mptcp_sk(sk)->timer_ival = 0; 414 } 415 416 static void mptcp_close_wake_up(struct sock *sk) 417 { 418 if (sock_flag(sk, SOCK_DEAD)) 419 return; 420 421 sk->sk_state_change(sk); 422 if (sk->sk_shutdown == SHUTDOWN_MASK || 423 sk->sk_state == TCP_CLOSE) 424 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 425 else 426 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 427 } 428 429 static bool mptcp_pending_data_fin_ack(struct sock *sk) 430 { 431 struct mptcp_sock *msk = mptcp_sk(sk); 432 433 return ((1 << sk->sk_state) & 434 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && 435 msk->write_seq == READ_ONCE(msk->snd_una); 436 } 437 438 static void mptcp_check_data_fin_ack(struct sock *sk) 439 { 440 struct mptcp_sock *msk = mptcp_sk(sk); 441 442 /* Look for an acknowledged DATA_FIN */ 443 if (mptcp_pending_data_fin_ack(sk)) { 444 WRITE_ONCE(msk->snd_data_fin_enable, 0); 445 446 switch (sk->sk_state) { 447 case TCP_FIN_WAIT1: 448 inet_sk_state_store(sk, TCP_FIN_WAIT2); 449 break; 450 case TCP_CLOSING: 451 case TCP_LAST_ACK: 452 inet_sk_state_store(sk, TCP_CLOSE); 453 break; 454 } 455 456 mptcp_close_wake_up(sk); 457 } 458 } 459 460 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 461 { 462 struct mptcp_sock *msk = mptcp_sk(sk); 463 464 if (READ_ONCE(msk->rcv_data_fin) && 465 ((1 << sk->sk_state) & 466 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { 467 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); 468 469 if (msk->ack_seq == rcv_data_fin_seq) { 470 if (seq) 471 *seq = rcv_data_fin_seq; 472 473 return true; 474 } 475 } 476 477 return false; 478 } 479 480 static void mptcp_set_datafin_timeout(struct sock *sk) 481 { 482 struct inet_connection_sock *icsk = inet_csk(sk); 483 u32 retransmits; 484 485 retransmits = min_t(u32, icsk->icsk_retransmits, 486 ilog2(TCP_RTO_MAX / TCP_RTO_MIN)); 487 488 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits; 489 } 490 491 static void __mptcp_set_timeout(struct sock *sk, long tout) 492 { 493 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; 494 } 495 496 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow) 497 { 498 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 499 500 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ? 501 inet_csk(ssk)->icsk_timeout - jiffies : 0; 502 } 503 504 static void mptcp_set_timeout(struct sock *sk) 505 { 506 struct mptcp_subflow_context *subflow; 507 long tout = 0; 508 509 mptcp_for_each_subflow(mptcp_sk(sk), subflow) 510 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 511 __mptcp_set_timeout(sk, tout); 512 } 513 514 static inline bool tcp_can_send_ack(const struct sock *ssk) 515 { 516 return !((1 << inet_sk_state_load(ssk)) & 517 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); 518 } 519 520 void __mptcp_subflow_send_ack(struct sock *ssk) 521 { 522 if (tcp_can_send_ack(ssk)) 523 tcp_send_ack(ssk); 524 } 525 526 static void mptcp_subflow_send_ack(struct sock *ssk) 527 { 528 bool slow; 529 530 slow = lock_sock_fast(ssk); 531 __mptcp_subflow_send_ack(ssk); 532 unlock_sock_fast(ssk, slow); 533 } 534 535 static void mptcp_send_ack(struct mptcp_sock *msk) 536 { 537 struct mptcp_subflow_context *subflow; 538 539 mptcp_for_each_subflow(msk, subflow) 540 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow)); 541 } 542 543 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk) 544 { 545 bool slow; 546 547 slow = lock_sock_fast(ssk); 548 if (tcp_can_send_ack(ssk)) 549 tcp_cleanup_rbuf(ssk, 1); 550 unlock_sock_fast(ssk, slow); 551 } 552 553 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty) 554 { 555 const struct inet_connection_sock *icsk = inet_csk(ssk); 556 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending); 557 const struct tcp_sock *tp = tcp_sk(ssk); 558 559 return (ack_pending & ICSK_ACK_SCHED) && 560 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) > 561 READ_ONCE(icsk->icsk_ack.rcv_mss)) || 562 (rx_empty && ack_pending & 563 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED))); 564 } 565 566 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) 567 { 568 int old_space = READ_ONCE(msk->old_wspace); 569 struct mptcp_subflow_context *subflow; 570 struct sock *sk = (struct sock *)msk; 571 int space = __mptcp_space(sk); 572 bool cleanup, rx_empty; 573 574 cleanup = (space > 0) && (space >= (old_space << 1)); 575 rx_empty = !__mptcp_rmem(sk); 576 577 mptcp_for_each_subflow(msk, subflow) { 578 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 579 580 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty)) 581 mptcp_subflow_cleanup_rbuf(ssk); 582 } 583 } 584 585 static bool mptcp_check_data_fin(struct sock *sk) 586 { 587 struct mptcp_sock *msk = mptcp_sk(sk); 588 u64 rcv_data_fin_seq; 589 bool ret = false; 590 591 /* Need to ack a DATA_FIN received from a peer while this side 592 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. 593 * msk->rcv_data_fin was set when parsing the incoming options 594 * at the subflow level and the msk lock was not held, so this 595 * is the first opportunity to act on the DATA_FIN and change 596 * the msk state. 597 * 598 * If we are caught up to the sequence number of the incoming 599 * DATA_FIN, send the DATA_ACK now and do state transition. If 600 * not caught up, do nothing and let the recv code send DATA_ACK 601 * when catching up. 602 */ 603 604 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { 605 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); 606 WRITE_ONCE(msk->rcv_data_fin, 0); 607 608 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN); 609 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 610 611 switch (sk->sk_state) { 612 case TCP_ESTABLISHED: 613 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 614 break; 615 case TCP_FIN_WAIT1: 616 inet_sk_state_store(sk, TCP_CLOSING); 617 break; 618 case TCP_FIN_WAIT2: 619 inet_sk_state_store(sk, TCP_CLOSE); 620 break; 621 default: 622 /* Other states not expected */ 623 WARN_ON_ONCE(1); 624 break; 625 } 626 627 ret = true; 628 if (!__mptcp_check_fallback(msk)) 629 mptcp_send_ack(msk); 630 mptcp_close_wake_up(sk); 631 } 632 return ret; 633 } 634 635 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 636 struct sock *ssk, 637 unsigned int *bytes) 638 { 639 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 640 struct sock *sk = (struct sock *)msk; 641 unsigned int moved = 0; 642 bool more_data_avail; 643 struct tcp_sock *tp; 644 bool done = false; 645 int sk_rbuf; 646 647 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 648 649 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 650 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 651 652 if (unlikely(ssk_rbuf > sk_rbuf)) { 653 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); 654 sk_rbuf = ssk_rbuf; 655 } 656 } 657 658 pr_debug("msk=%p ssk=%p", msk, ssk); 659 tp = tcp_sk(ssk); 660 do { 661 u32 map_remaining, offset; 662 u32 seq = tp->copied_seq; 663 struct sk_buff *skb; 664 bool fin; 665 666 /* try to move as much data as available */ 667 map_remaining = subflow->map_data_len - 668 mptcp_subflow_get_map_offset(subflow); 669 670 skb = skb_peek(&ssk->sk_receive_queue); 671 if (!skb) { 672 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(), 673 * a different CPU can have already processed the pending 674 * data, stop here or we can enter an infinite loop 675 */ 676 if (!moved) 677 done = true; 678 break; 679 } 680 681 if (__mptcp_check_fallback(msk)) { 682 /* Under fallback skbs have no MPTCP extension and TCP could 683 * collapse them between the dummy map creation and the 684 * current dequeue. Be sure to adjust the map size. 685 */ 686 map_remaining = skb->len; 687 subflow->map_data_len = skb->len; 688 } 689 690 offset = seq - TCP_SKB_CB(skb)->seq; 691 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; 692 if (fin) { 693 done = true; 694 seq++; 695 } 696 697 if (offset < skb->len) { 698 size_t len = skb->len - offset; 699 700 if (tp->urg_data) 701 done = true; 702 703 if (__mptcp_move_skb(msk, ssk, skb, offset, len)) 704 moved += len; 705 seq += len; 706 707 if (WARN_ON_ONCE(map_remaining < len)) 708 break; 709 } else { 710 WARN_ON_ONCE(!fin); 711 sk_eat_skb(ssk, skb); 712 done = true; 713 } 714 715 WRITE_ONCE(tp->copied_seq, seq); 716 more_data_avail = mptcp_subflow_data_available(ssk); 717 718 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { 719 done = true; 720 break; 721 } 722 } while (more_data_avail); 723 724 *bytes += moved; 725 return done; 726 } 727 728 static bool __mptcp_ofo_queue(struct mptcp_sock *msk) 729 { 730 struct sock *sk = (struct sock *)msk; 731 struct sk_buff *skb, *tail; 732 bool moved = false; 733 struct rb_node *p; 734 u64 end_seq; 735 736 p = rb_first(&msk->out_of_order_queue); 737 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); 738 while (p) { 739 skb = rb_to_skb(p); 740 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) 741 break; 742 743 p = rb_next(p); 744 rb_erase(&skb->rbnode, &msk->out_of_order_queue); 745 746 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, 747 msk->ack_seq))) { 748 mptcp_drop(sk, skb); 749 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 750 continue; 751 } 752 753 end_seq = MPTCP_SKB_CB(skb)->end_seq; 754 tail = skb_peek_tail(&sk->sk_receive_queue); 755 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { 756 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 757 758 /* skip overlapping data, if any */ 759 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", 760 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, 761 delta); 762 MPTCP_SKB_CB(skb)->offset += delta; 763 MPTCP_SKB_CB(skb)->map_seq += delta; 764 __skb_queue_tail(&sk->sk_receive_queue, skb); 765 } 766 msk->bytes_received += end_seq - msk->ack_seq; 767 msk->ack_seq = end_seq; 768 moved = true; 769 } 770 return moved; 771 } 772 773 static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk) 774 { 775 int err = sock_error(ssk); 776 int ssk_state; 777 778 if (!err) 779 return false; 780 781 /* only propagate errors on fallen-back sockets or 782 * on MPC connect 783 */ 784 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) 785 return false; 786 787 /* We need to propagate only transition to CLOSE state. 788 * Orphaned socket will see such state change via 789 * subflow_sched_work_if_closed() and that path will properly 790 * destroy the msk as needed. 791 */ 792 ssk_state = inet_sk_state_load(ssk); 793 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD)) 794 inet_sk_state_store(sk, ssk_state); 795 WRITE_ONCE(sk->sk_err, -err); 796 797 /* This barrier is coupled with smp_rmb() in mptcp_poll() */ 798 smp_wmb(); 799 sk_error_report(sk); 800 return true; 801 } 802 803 void __mptcp_error_report(struct sock *sk) 804 { 805 struct mptcp_subflow_context *subflow; 806 struct mptcp_sock *msk = mptcp_sk(sk); 807 808 mptcp_for_each_subflow(msk, subflow) 809 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow))) 810 break; 811 } 812 813 /* In most cases we will be able to lock the mptcp socket. If its already 814 * owned, we need to defer to the work queue to avoid ABBA deadlock. 815 */ 816 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 817 { 818 struct sock *sk = (struct sock *)msk; 819 unsigned int moved = 0; 820 821 __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 822 __mptcp_ofo_queue(msk); 823 if (unlikely(ssk->sk_err)) { 824 if (!sock_owned_by_user(sk)) 825 __mptcp_error_report(sk); 826 else 827 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags); 828 } 829 830 /* If the moves have caught up with the DATA_FIN sequence number 831 * it's time to ack the DATA_FIN and change socket state, but 832 * this is not a good place to change state. Let the workqueue 833 * do it. 834 */ 835 if (mptcp_pending_data_fin(sk, NULL)) 836 mptcp_schedule_work(sk); 837 return moved > 0; 838 } 839 840 void mptcp_data_ready(struct sock *sk, struct sock *ssk) 841 { 842 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 843 struct mptcp_sock *msk = mptcp_sk(sk); 844 int sk_rbuf, ssk_rbuf; 845 846 /* The peer can send data while we are shutting down this 847 * subflow at msk destruction time, but we must avoid enqueuing 848 * more data to the msk receive queue 849 */ 850 if (unlikely(subflow->disposable)) 851 return; 852 853 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 854 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 855 if (unlikely(ssk_rbuf > sk_rbuf)) 856 sk_rbuf = ssk_rbuf; 857 858 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ 859 if (__mptcp_rmem(sk) > sk_rbuf) { 860 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); 861 return; 862 } 863 864 /* Wake-up the reader only for in-sequence data */ 865 mptcp_data_lock(sk); 866 if (move_skbs_to_msk(msk, ssk)) 867 sk->sk_data_ready(sk); 868 869 mptcp_data_unlock(sk); 870 } 871 872 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk) 873 { 874 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq); 875 WRITE_ONCE(msk->allow_infinite_fallback, false); 876 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); 877 } 878 879 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) 880 { 881 struct sock *sk = (struct sock *)msk; 882 883 if (sk->sk_state != TCP_ESTABLISHED) 884 return false; 885 886 /* attach to msk socket only after we are sure we will deal with it 887 * at close time 888 */ 889 if (sk->sk_socket && !ssk->sk_socket) 890 mptcp_sock_graft(ssk, sk->sk_socket); 891 892 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++; 893 mptcp_sockopt_sync_locked(msk, ssk); 894 mptcp_subflow_joined(msk, ssk); 895 mptcp_stop_tout_timer(sk); 896 __mptcp_propagate_sndbuf(sk, ssk); 897 return true; 898 } 899 900 static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list) 901 { 902 struct mptcp_subflow_context *tmp, *subflow; 903 struct mptcp_sock *msk = mptcp_sk(sk); 904 905 list_for_each_entry_safe(subflow, tmp, join_list, node) { 906 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 907 bool slow = lock_sock_fast(ssk); 908 909 list_move_tail(&subflow->node, &msk->conn_list); 910 if (!__mptcp_finish_join(msk, ssk)) 911 mptcp_subflow_reset(ssk); 912 unlock_sock_fast(ssk, slow); 913 } 914 } 915 916 static bool mptcp_rtx_timer_pending(struct sock *sk) 917 { 918 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); 919 } 920 921 static void mptcp_reset_rtx_timer(struct sock *sk) 922 { 923 struct inet_connection_sock *icsk = inet_csk(sk); 924 unsigned long tout; 925 926 /* prevent rescheduling on close */ 927 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) 928 return; 929 930 tout = mptcp_sk(sk)->timer_ival; 931 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); 932 } 933 934 bool mptcp_schedule_work(struct sock *sk) 935 { 936 if (inet_sk_state_load(sk) != TCP_CLOSE && 937 schedule_work(&mptcp_sk(sk)->work)) { 938 /* each subflow already holds a reference to the sk, and the 939 * workqueue is invoked by a subflow, so sk can't go away here. 940 */ 941 sock_hold(sk); 942 return true; 943 } 944 return false; 945 } 946 947 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) 948 { 949 struct mptcp_subflow_context *subflow; 950 951 msk_owned_by_me(msk); 952 953 mptcp_for_each_subflow(msk, subflow) { 954 if (READ_ONCE(subflow->data_avail)) 955 return mptcp_subflow_tcp_sock(subflow); 956 } 957 958 return NULL; 959 } 960 961 static bool mptcp_skb_can_collapse_to(u64 write_seq, 962 const struct sk_buff *skb, 963 const struct mptcp_ext *mpext) 964 { 965 if (!tcp_skb_can_collapse_to(skb)) 966 return false; 967 968 /* can collapse only if MPTCP level sequence is in order and this 969 * mapping has not been xmitted yet 970 */ 971 return mpext && mpext->data_seq + mpext->data_len == write_seq && 972 !mpext->frozen; 973 } 974 975 /* we can append data to the given data frag if: 976 * - there is space available in the backing page_frag 977 * - the data frag tail matches the current page_frag free offset 978 * - the data frag end sequence number matches the current write seq 979 */ 980 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 981 const struct page_frag *pfrag, 982 const struct mptcp_data_frag *df) 983 { 984 return df && pfrag->page == df->page && 985 pfrag->size - pfrag->offset > 0 && 986 pfrag->offset == (df->offset + df->data_len) && 987 df->data_seq + df->data_len == msk->write_seq; 988 } 989 990 static void dfrag_uncharge(struct sock *sk, int len) 991 { 992 sk_mem_uncharge(sk, len); 993 sk_wmem_queued_add(sk, -len); 994 } 995 996 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 997 { 998 int len = dfrag->data_len + dfrag->overhead; 999 1000 list_del(&dfrag->list); 1001 dfrag_uncharge(sk, len); 1002 put_page(dfrag->page); 1003 } 1004 1005 static void __mptcp_clean_una(struct sock *sk) 1006 { 1007 struct mptcp_sock *msk = mptcp_sk(sk); 1008 struct mptcp_data_frag *dtmp, *dfrag; 1009 u64 snd_una; 1010 1011 snd_una = msk->snd_una; 1012 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 1013 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 1014 break; 1015 1016 if (unlikely(dfrag == msk->first_pending)) { 1017 /* in recovery mode can see ack after the current snd head */ 1018 if (WARN_ON_ONCE(!msk->recovery)) 1019 break; 1020 1021 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1022 } 1023 1024 dfrag_clear(sk, dfrag); 1025 } 1026 1027 dfrag = mptcp_rtx_head(sk); 1028 if (dfrag && after64(snd_una, dfrag->data_seq)) { 1029 u64 delta = snd_una - dfrag->data_seq; 1030 1031 /* prevent wrap around in recovery mode */ 1032 if (unlikely(delta > dfrag->already_sent)) { 1033 if (WARN_ON_ONCE(!msk->recovery)) 1034 goto out; 1035 if (WARN_ON_ONCE(delta > dfrag->data_len)) 1036 goto out; 1037 dfrag->already_sent += delta - dfrag->already_sent; 1038 } 1039 1040 dfrag->data_seq += delta; 1041 dfrag->offset += delta; 1042 dfrag->data_len -= delta; 1043 dfrag->already_sent -= delta; 1044 1045 dfrag_uncharge(sk, delta); 1046 } 1047 1048 /* all retransmitted data acked, recovery completed */ 1049 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) 1050 msk->recovery = false; 1051 1052 out: 1053 if (snd_una == READ_ONCE(msk->snd_nxt) && 1054 snd_una == READ_ONCE(msk->write_seq)) { 1055 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) 1056 mptcp_stop_rtx_timer(sk); 1057 } else { 1058 mptcp_reset_rtx_timer(sk); 1059 } 1060 } 1061 1062 static void __mptcp_clean_una_wakeup(struct sock *sk) 1063 { 1064 lockdep_assert_held_once(&sk->sk_lock.slock); 1065 1066 __mptcp_clean_una(sk); 1067 mptcp_write_space(sk); 1068 } 1069 1070 static void mptcp_clean_una_wakeup(struct sock *sk) 1071 { 1072 mptcp_data_lock(sk); 1073 __mptcp_clean_una_wakeup(sk); 1074 mptcp_data_unlock(sk); 1075 } 1076 1077 static void mptcp_enter_memory_pressure(struct sock *sk) 1078 { 1079 struct mptcp_subflow_context *subflow; 1080 struct mptcp_sock *msk = mptcp_sk(sk); 1081 bool first = true; 1082 1083 mptcp_for_each_subflow(msk, subflow) { 1084 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1085 1086 if (first) 1087 tcp_enter_memory_pressure(ssk); 1088 sk_stream_moderate_sndbuf(ssk); 1089 1090 first = false; 1091 } 1092 __mptcp_sync_sndbuf(sk); 1093 } 1094 1095 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 1096 * data 1097 */ 1098 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 1099 { 1100 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 1101 pfrag, sk->sk_allocation))) 1102 return true; 1103 1104 mptcp_enter_memory_pressure(sk); 1105 return false; 1106 } 1107 1108 static struct mptcp_data_frag * 1109 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 1110 int orig_offset) 1111 { 1112 int offset = ALIGN(orig_offset, sizeof(long)); 1113 struct mptcp_data_frag *dfrag; 1114 1115 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 1116 dfrag->data_len = 0; 1117 dfrag->data_seq = msk->write_seq; 1118 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 1119 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 1120 dfrag->already_sent = 0; 1121 dfrag->page = pfrag->page; 1122 1123 return dfrag; 1124 } 1125 1126 struct mptcp_sendmsg_info { 1127 int mss_now; 1128 int size_goal; 1129 u16 limit; 1130 u16 sent; 1131 unsigned int flags; 1132 bool data_lock_held; 1133 }; 1134 1135 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk, 1136 u64 data_seq, int avail_size) 1137 { 1138 u64 window_end = mptcp_wnd_end(msk); 1139 u64 mptcp_snd_wnd; 1140 1141 if (__mptcp_check_fallback(msk)) 1142 return avail_size; 1143 1144 mptcp_snd_wnd = window_end - data_seq; 1145 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size); 1146 1147 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) { 1148 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd); 1149 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED); 1150 } 1151 1152 return avail_size; 1153 } 1154 1155 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) 1156 { 1157 struct skb_ext *mpext = __skb_ext_alloc(gfp); 1158 1159 if (!mpext) 1160 return false; 1161 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); 1162 return true; 1163 } 1164 1165 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) 1166 { 1167 struct sk_buff *skb; 1168 1169 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); 1170 if (likely(skb)) { 1171 if (likely(__mptcp_add_ext(skb, gfp))) { 1172 skb_reserve(skb, MAX_TCP_HEADER); 1173 skb->ip_summed = CHECKSUM_PARTIAL; 1174 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); 1175 return skb; 1176 } 1177 __kfree_skb(skb); 1178 } else { 1179 mptcp_enter_memory_pressure(sk); 1180 } 1181 return NULL; 1182 } 1183 1184 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) 1185 { 1186 struct sk_buff *skb; 1187 1188 skb = __mptcp_do_alloc_tx_skb(sk, gfp); 1189 if (!skb) 1190 return NULL; 1191 1192 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1193 tcp_skb_entail(ssk, skb); 1194 return skb; 1195 } 1196 tcp_skb_tsorted_anchor_cleanup(skb); 1197 kfree_skb(skb); 1198 return NULL; 1199 } 1200 1201 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) 1202 { 1203 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; 1204 1205 return __mptcp_alloc_tx_skb(sk, ssk, gfp); 1206 } 1207 1208 /* note: this always recompute the csum on the whole skb, even 1209 * if we just appended a single frag. More status info needed 1210 */ 1211 static void mptcp_update_data_checksum(struct sk_buff *skb, int added) 1212 { 1213 struct mptcp_ext *mpext = mptcp_get_ext(skb); 1214 __wsum csum = ~csum_unfold(mpext->csum); 1215 int offset = skb->len - added; 1216 1217 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset)); 1218 } 1219 1220 static void mptcp_update_infinite_map(struct mptcp_sock *msk, 1221 struct sock *ssk, 1222 struct mptcp_ext *mpext) 1223 { 1224 if (!mpext) 1225 return; 1226 1227 mpext->infinite_map = 1; 1228 mpext->data_len = 0; 1229 1230 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); 1231 mptcp_subflow_ctx(ssk)->send_infinite_map = 0; 1232 pr_fallback(msk); 1233 mptcp_do_fallback(ssk); 1234 } 1235 1236 #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1)) 1237 1238 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 1239 struct mptcp_data_frag *dfrag, 1240 struct mptcp_sendmsg_info *info) 1241 { 1242 u64 data_seq = dfrag->data_seq + info->sent; 1243 int offset = dfrag->offset + info->sent; 1244 struct mptcp_sock *msk = mptcp_sk(sk); 1245 bool zero_window_probe = false; 1246 struct mptcp_ext *mpext = NULL; 1247 bool can_coalesce = false; 1248 bool reuse_skb = true; 1249 struct sk_buff *skb; 1250 size_t copy; 1251 int i; 1252 1253 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", 1254 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); 1255 1256 if (WARN_ON_ONCE(info->sent > info->limit || 1257 info->limit > dfrag->data_len)) 1258 return 0; 1259 1260 if (unlikely(!__tcp_can_send(ssk))) 1261 return -EAGAIN; 1262 1263 /* compute send limit */ 1264 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE)) 1265 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE; 1266 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); 1267 copy = info->size_goal; 1268 1269 skb = tcp_write_queue_tail(ssk); 1270 if (skb && copy > skb->len) { 1271 /* Limit the write to the size available in the 1272 * current skb, if any, so that we create at most a new skb. 1273 * Explicitly tells TCP internals to avoid collapsing on later 1274 * queue management operation, to avoid breaking the ext <-> 1275 * SSN association set here 1276 */ 1277 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1278 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { 1279 TCP_SKB_CB(skb)->eor = 1; 1280 goto alloc_skb; 1281 } 1282 1283 i = skb_shinfo(skb)->nr_frags; 1284 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); 1285 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) { 1286 tcp_mark_push(tcp_sk(ssk), skb); 1287 goto alloc_skb; 1288 } 1289 1290 copy -= skb->len; 1291 } else { 1292 alloc_skb: 1293 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held); 1294 if (!skb) 1295 return -ENOMEM; 1296 1297 i = skb_shinfo(skb)->nr_frags; 1298 reuse_skb = false; 1299 mpext = skb_ext_find(skb, SKB_EXT_MPTCP); 1300 } 1301 1302 /* Zero window and all data acked? Probe. */ 1303 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy); 1304 if (copy == 0) { 1305 u64 snd_una = READ_ONCE(msk->snd_una); 1306 1307 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) { 1308 tcp_remove_empty_skb(ssk); 1309 return 0; 1310 } 1311 1312 zero_window_probe = true; 1313 data_seq = snd_una - 1; 1314 copy = 1; 1315 } 1316 1317 copy = min_t(size_t, copy, info->limit - info->sent); 1318 if (!sk_wmem_schedule(ssk, copy)) { 1319 tcp_remove_empty_skb(ssk); 1320 return -ENOMEM; 1321 } 1322 1323 if (can_coalesce) { 1324 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1325 } else { 1326 get_page(dfrag->page); 1327 skb_fill_page_desc(skb, i, dfrag->page, offset, copy); 1328 } 1329 1330 skb->len += copy; 1331 skb->data_len += copy; 1332 skb->truesize += copy; 1333 sk_wmem_queued_add(ssk, copy); 1334 sk_mem_charge(ssk, copy); 1335 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy); 1336 TCP_SKB_CB(skb)->end_seq += copy; 1337 tcp_skb_pcount_set(skb, 0); 1338 1339 /* on skb reuse we just need to update the DSS len */ 1340 if (reuse_skb) { 1341 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1342 mpext->data_len += copy; 1343 goto out; 1344 } 1345 1346 memset(mpext, 0, sizeof(*mpext)); 1347 mpext->data_seq = data_seq; 1348 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 1349 mpext->data_len = copy; 1350 mpext->use_map = 1; 1351 mpext->dsn64 = 1; 1352 1353 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 1354 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 1355 mpext->dsn64); 1356 1357 if (zero_window_probe) { 1358 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1359 mpext->frozen = 1; 1360 if (READ_ONCE(msk->csum_enabled)) 1361 mptcp_update_data_checksum(skb, copy); 1362 tcp_push_pending_frames(ssk); 1363 return 0; 1364 } 1365 out: 1366 if (READ_ONCE(msk->csum_enabled)) 1367 mptcp_update_data_checksum(skb, copy); 1368 if (mptcp_subflow_ctx(ssk)->send_infinite_map) 1369 mptcp_update_infinite_map(msk, ssk, mpext); 1370 trace_mptcp_sendmsg_frag(mpext); 1371 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1372 return copy; 1373 } 1374 1375 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ 1376 sizeof(struct tcphdr) - \ 1377 MAX_TCP_OPTION_SPACE - \ 1378 sizeof(struct ipv6hdr) - \ 1379 sizeof(struct frag_hdr)) 1380 1381 struct subflow_send_info { 1382 struct sock *ssk; 1383 u64 linger_time; 1384 }; 1385 1386 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow) 1387 { 1388 if (!subflow->stale) 1389 return; 1390 1391 subflow->stale = 0; 1392 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER); 1393 } 1394 1395 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) 1396 { 1397 if (unlikely(subflow->stale)) { 1398 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp); 1399 1400 if (subflow->stale_rcv_tstamp == rcv_tstamp) 1401 return false; 1402 1403 mptcp_subflow_set_active(subflow); 1404 } 1405 return __mptcp_subflow_active(subflow); 1406 } 1407 1408 #define SSK_MODE_ACTIVE 0 1409 #define SSK_MODE_BACKUP 1 1410 #define SSK_MODE_MAX 2 1411 1412 /* implement the mptcp packet scheduler; 1413 * returns the subflow that will transmit the next DSS 1414 * additionally updates the rtx timeout 1415 */ 1416 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 1417 { 1418 struct subflow_send_info send_info[SSK_MODE_MAX]; 1419 struct mptcp_subflow_context *subflow; 1420 struct sock *sk = (struct sock *)msk; 1421 u32 pace, burst, wmem; 1422 int i, nr_active = 0; 1423 struct sock *ssk; 1424 u64 linger_time; 1425 long tout = 0; 1426 1427 /* pick the subflow with the lower wmem/wspace ratio */ 1428 for (i = 0; i < SSK_MODE_MAX; ++i) { 1429 send_info[i].ssk = NULL; 1430 send_info[i].linger_time = -1; 1431 } 1432 1433 mptcp_for_each_subflow(msk, subflow) { 1434 trace_mptcp_subflow_get_send(subflow); 1435 ssk = mptcp_subflow_tcp_sock(subflow); 1436 if (!mptcp_subflow_active(subflow)) 1437 continue; 1438 1439 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 1440 nr_active += !subflow->backup; 1441 pace = subflow->avg_pacing_rate; 1442 if (unlikely(!pace)) { 1443 /* init pacing rate from socket */ 1444 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate); 1445 pace = subflow->avg_pacing_rate; 1446 if (!pace) 1447 continue; 1448 } 1449 1450 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); 1451 if (linger_time < send_info[subflow->backup].linger_time) { 1452 send_info[subflow->backup].ssk = ssk; 1453 send_info[subflow->backup].linger_time = linger_time; 1454 } 1455 } 1456 __mptcp_set_timeout(sk, tout); 1457 1458 /* pick the best backup if no other subflow is active */ 1459 if (!nr_active) 1460 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk; 1461 1462 /* According to the blest algorithm, to avoid HoL blocking for the 1463 * faster flow, we need to: 1464 * - estimate the faster flow linger time 1465 * - use the above to estimate the amount of byte transferred 1466 * by the faster flow 1467 * - check that the amount of queued data is greter than the above, 1468 * otherwise do not use the picked, slower, subflow 1469 * We select the subflow with the shorter estimated time to flush 1470 * the queued mem, which basically ensure the above. We just need 1471 * to check that subflow has a non empty cwin. 1472 */ 1473 ssk = send_info[SSK_MODE_ACTIVE].ssk; 1474 if (!ssk || !sk_stream_memory_free(ssk)) 1475 return NULL; 1476 1477 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt); 1478 wmem = READ_ONCE(ssk->sk_wmem_queued); 1479 if (!burst) 1480 return ssk; 1481 1482 subflow = mptcp_subflow_ctx(ssk); 1483 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem + 1484 READ_ONCE(ssk->sk_pacing_rate) * burst, 1485 burst + wmem); 1486 msk->snd_burst = burst; 1487 return ssk; 1488 } 1489 1490 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) 1491 { 1492 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); 1493 release_sock(ssk); 1494 } 1495 1496 static void mptcp_update_post_push(struct mptcp_sock *msk, 1497 struct mptcp_data_frag *dfrag, 1498 u32 sent) 1499 { 1500 u64 snd_nxt_new = dfrag->data_seq; 1501 1502 dfrag->already_sent += sent; 1503 1504 msk->snd_burst -= sent; 1505 1506 snd_nxt_new += dfrag->already_sent; 1507 1508 /* snd_nxt_new can be smaller than snd_nxt in case mptcp 1509 * is recovering after a failover. In that event, this re-sends 1510 * old segments. 1511 * 1512 * Thus compute snd_nxt_new candidate based on 1513 * the dfrag->data_seq that was sent and the data 1514 * that has been handed to the subflow for transmission 1515 * and skip update in case it was old dfrag. 1516 */ 1517 if (likely(after64(snd_nxt_new, msk->snd_nxt))) { 1518 msk->bytes_sent += snd_nxt_new - msk->snd_nxt; 1519 msk->snd_nxt = snd_nxt_new; 1520 } 1521 } 1522 1523 void mptcp_check_and_set_pending(struct sock *sk) 1524 { 1525 if (mptcp_send_head(sk)) { 1526 mptcp_data_lock(sk); 1527 mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING); 1528 mptcp_data_unlock(sk); 1529 } 1530 } 1531 1532 static int __subflow_push_pending(struct sock *sk, struct sock *ssk, 1533 struct mptcp_sendmsg_info *info) 1534 { 1535 struct mptcp_sock *msk = mptcp_sk(sk); 1536 struct mptcp_data_frag *dfrag; 1537 int len, copied = 0, err = 0; 1538 1539 while ((dfrag = mptcp_send_head(sk))) { 1540 info->sent = dfrag->already_sent; 1541 info->limit = dfrag->data_len; 1542 len = dfrag->data_len - dfrag->already_sent; 1543 while (len > 0) { 1544 int ret = 0; 1545 1546 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info); 1547 if (ret <= 0) { 1548 err = copied ? : ret; 1549 goto out; 1550 } 1551 1552 info->sent += ret; 1553 copied += ret; 1554 len -= ret; 1555 1556 mptcp_update_post_push(msk, dfrag, ret); 1557 } 1558 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1559 1560 if (msk->snd_burst <= 0 || 1561 !sk_stream_memory_free(ssk) || 1562 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) { 1563 err = copied; 1564 goto out; 1565 } 1566 mptcp_set_timeout(sk); 1567 } 1568 err = copied; 1569 1570 out: 1571 return err; 1572 } 1573 1574 void __mptcp_push_pending(struct sock *sk, unsigned int flags) 1575 { 1576 struct sock *prev_ssk = NULL, *ssk = NULL; 1577 struct mptcp_sock *msk = mptcp_sk(sk); 1578 struct mptcp_sendmsg_info info = { 1579 .flags = flags, 1580 }; 1581 bool do_check_data_fin = false; 1582 int push_count = 1; 1583 1584 while (mptcp_send_head(sk) && (push_count > 0)) { 1585 struct mptcp_subflow_context *subflow; 1586 int ret = 0; 1587 1588 if (mptcp_sched_get_send(msk)) 1589 break; 1590 1591 push_count = 0; 1592 1593 mptcp_for_each_subflow(msk, subflow) { 1594 if (READ_ONCE(subflow->scheduled)) { 1595 mptcp_subflow_set_scheduled(subflow, false); 1596 1597 prev_ssk = ssk; 1598 ssk = mptcp_subflow_tcp_sock(subflow); 1599 if (ssk != prev_ssk) { 1600 /* First check. If the ssk has changed since 1601 * the last round, release prev_ssk 1602 */ 1603 if (prev_ssk) 1604 mptcp_push_release(prev_ssk, &info); 1605 1606 /* Need to lock the new subflow only if different 1607 * from the previous one, otherwise we are still 1608 * helding the relevant lock 1609 */ 1610 lock_sock(ssk); 1611 } 1612 1613 push_count++; 1614 1615 ret = __subflow_push_pending(sk, ssk, &info); 1616 if (ret <= 0) { 1617 if (ret != -EAGAIN || 1618 (1 << ssk->sk_state) & 1619 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE)) 1620 push_count--; 1621 continue; 1622 } 1623 do_check_data_fin = true; 1624 } 1625 } 1626 } 1627 1628 /* at this point we held the socket lock for the last subflow we used */ 1629 if (ssk) 1630 mptcp_push_release(ssk, &info); 1631 1632 /* ensure the rtx timer is running */ 1633 if (!mptcp_rtx_timer_pending(sk)) 1634 mptcp_reset_rtx_timer(sk); 1635 if (do_check_data_fin) 1636 mptcp_check_send_data_fin(sk); 1637 } 1638 1639 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) 1640 { 1641 struct mptcp_sock *msk = mptcp_sk(sk); 1642 struct mptcp_sendmsg_info info = { 1643 .data_lock_held = true, 1644 }; 1645 bool keep_pushing = true; 1646 struct sock *xmit_ssk; 1647 int copied = 0; 1648 1649 info.flags = 0; 1650 while (mptcp_send_head(sk) && keep_pushing) { 1651 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 1652 int ret = 0; 1653 1654 /* check for a different subflow usage only after 1655 * spooling the first chunk of data 1656 */ 1657 if (first) { 1658 mptcp_subflow_set_scheduled(subflow, false); 1659 ret = __subflow_push_pending(sk, ssk, &info); 1660 first = false; 1661 if (ret <= 0) 1662 break; 1663 copied += ret; 1664 continue; 1665 } 1666 1667 if (mptcp_sched_get_send(msk)) 1668 goto out; 1669 1670 if (READ_ONCE(subflow->scheduled)) { 1671 mptcp_subflow_set_scheduled(subflow, false); 1672 ret = __subflow_push_pending(sk, ssk, &info); 1673 if (ret <= 0) 1674 keep_pushing = false; 1675 copied += ret; 1676 } 1677 1678 mptcp_for_each_subflow(msk, subflow) { 1679 if (READ_ONCE(subflow->scheduled)) { 1680 xmit_ssk = mptcp_subflow_tcp_sock(subflow); 1681 if (xmit_ssk != ssk) { 1682 mptcp_subflow_delegate(subflow, 1683 MPTCP_DELEGATE_SEND); 1684 keep_pushing = false; 1685 } 1686 } 1687 } 1688 } 1689 1690 out: 1691 /* __mptcp_alloc_tx_skb could have released some wmem and we are 1692 * not going to flush it via release_sock() 1693 */ 1694 if (copied) { 1695 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 1696 info.size_goal); 1697 if (!mptcp_rtx_timer_pending(sk)) 1698 mptcp_reset_rtx_timer(sk); 1699 1700 if (msk->snd_data_fin_enable && 1701 msk->snd_nxt + 1 == msk->write_seq) 1702 mptcp_schedule_work(sk); 1703 } 1704 } 1705 1706 static void mptcp_set_nospace(struct sock *sk) 1707 { 1708 /* enable autotune */ 1709 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1710 1711 /* will be cleared on avail space */ 1712 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); 1713 } 1714 1715 static int mptcp_disconnect(struct sock *sk, int flags); 1716 1717 static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, 1718 size_t len, int *copied_syn) 1719 { 1720 unsigned int saved_flags = msg->msg_flags; 1721 struct mptcp_sock *msk = mptcp_sk(sk); 1722 struct sock *ssk; 1723 int ret; 1724 1725 /* on flags based fastopen the mptcp is supposed to create the 1726 * first subflow right now. Otherwise we are in the defer_connect 1727 * path, and the first subflow must be already present. 1728 * Since the defer_connect flag is cleared after the first succsful 1729 * fastopen attempt, no need to check for additional subflow status. 1730 */ 1731 if (msg->msg_flags & MSG_FASTOPEN) { 1732 ssk = __mptcp_nmpc_sk(msk); 1733 if (IS_ERR(ssk)) 1734 return PTR_ERR(ssk); 1735 } 1736 if (!msk->first) 1737 return -EINVAL; 1738 1739 ssk = msk->first; 1740 1741 lock_sock(ssk); 1742 msg->msg_flags |= MSG_DONTWAIT; 1743 msk->fastopening = 1; 1744 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL); 1745 msk->fastopening = 0; 1746 msg->msg_flags = saved_flags; 1747 release_sock(ssk); 1748 1749 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */ 1750 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) { 1751 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1752 msg->msg_namelen, msg->msg_flags, 1); 1753 1754 /* Keep the same behaviour of plain TCP: zero the copied bytes in 1755 * case of any error, except timeout or signal 1756 */ 1757 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) 1758 *copied_syn = 0; 1759 } else if (ret && ret != -EINPROGRESS) { 1760 /* The disconnect() op called by tcp_sendmsg_fastopen()/ 1761 * __inet_stream_connect() can fail, due to looking check, 1762 * see mptcp_disconnect(). 1763 * Attempt it again outside the problematic scope. 1764 */ 1765 if (!mptcp_disconnect(sk, 0)) 1766 sk->sk_socket->state = SS_UNCONNECTED; 1767 } 1768 inet_clear_bit(DEFER_CONNECT, sk); 1769 1770 return ret; 1771 } 1772 1773 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1774 { 1775 struct mptcp_sock *msk = mptcp_sk(sk); 1776 struct page_frag *pfrag; 1777 size_t copied = 0; 1778 int ret = 0; 1779 long timeo; 1780 1781 /* silently ignore everything else */ 1782 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN; 1783 1784 lock_sock(sk); 1785 1786 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) || 1787 msg->msg_flags & MSG_FASTOPEN)) { 1788 int copied_syn = 0; 1789 1790 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn); 1791 copied += copied_syn; 1792 if (ret == -EINPROGRESS && copied_syn > 0) 1793 goto out; 1794 else if (ret) 1795 goto do_error; 1796 } 1797 1798 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1799 1800 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 1801 ret = sk_stream_wait_connect(sk, &timeo); 1802 if (ret) 1803 goto do_error; 1804 } 1805 1806 ret = -EPIPE; 1807 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))) 1808 goto do_error; 1809 1810 pfrag = sk_page_frag(sk); 1811 1812 while (msg_data_left(msg)) { 1813 int total_ts, frag_truesize = 0; 1814 struct mptcp_data_frag *dfrag; 1815 bool dfrag_collapsed; 1816 size_t psize, offset; 1817 1818 /* reuse tail pfrag, if possible, or carve a new one from the 1819 * page allocator 1820 */ 1821 dfrag = mptcp_pending_tail(sk); 1822 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 1823 if (!dfrag_collapsed) { 1824 if (!sk_stream_memory_free(sk)) 1825 goto wait_for_memory; 1826 1827 if (!mptcp_page_frag_refill(sk, pfrag)) 1828 goto wait_for_memory; 1829 1830 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); 1831 frag_truesize = dfrag->overhead; 1832 } 1833 1834 /* we do not bound vs wspace, to allow a single packet. 1835 * memory accounting will prevent execessive memory usage 1836 * anyway 1837 */ 1838 offset = dfrag->offset + dfrag->data_len; 1839 psize = pfrag->size - offset; 1840 psize = min_t(size_t, psize, msg_data_left(msg)); 1841 total_ts = psize + frag_truesize; 1842 1843 if (!sk_wmem_schedule(sk, total_ts)) 1844 goto wait_for_memory; 1845 1846 if (copy_page_from_iter(dfrag->page, offset, psize, 1847 &msg->msg_iter) != psize) { 1848 ret = -EFAULT; 1849 goto do_error; 1850 } 1851 1852 /* data successfully copied into the write queue */ 1853 sk_forward_alloc_add(sk, -total_ts); 1854 copied += psize; 1855 dfrag->data_len += psize; 1856 frag_truesize += psize; 1857 pfrag->offset += frag_truesize; 1858 WRITE_ONCE(msk->write_seq, msk->write_seq + psize); 1859 1860 /* charge data on mptcp pending queue to the msk socket 1861 * Note: we charge such data both to sk and ssk 1862 */ 1863 sk_wmem_queued_add(sk, frag_truesize); 1864 if (!dfrag_collapsed) { 1865 get_page(dfrag->page); 1866 list_add_tail(&dfrag->list, &msk->rtx_queue); 1867 if (!msk->first_pending) 1868 WRITE_ONCE(msk->first_pending, dfrag); 1869 } 1870 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, 1871 dfrag->data_seq, dfrag->data_len, dfrag->already_sent, 1872 !dfrag_collapsed); 1873 1874 continue; 1875 1876 wait_for_memory: 1877 mptcp_set_nospace(sk); 1878 __mptcp_push_pending(sk, msg->msg_flags); 1879 ret = sk_stream_wait_memory(sk, &timeo); 1880 if (ret) 1881 goto do_error; 1882 } 1883 1884 if (copied) 1885 __mptcp_push_pending(sk, msg->msg_flags); 1886 1887 out: 1888 release_sock(sk); 1889 return copied; 1890 1891 do_error: 1892 if (copied) 1893 goto out; 1894 1895 copied = sk_stream_error(sk, msg->msg_flags, ret); 1896 goto out; 1897 } 1898 1899 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1900 struct msghdr *msg, 1901 size_t len, int flags, 1902 struct scm_timestamping_internal *tss, 1903 int *cmsg_flags) 1904 { 1905 struct sk_buff *skb, *tmp; 1906 int copied = 0; 1907 1908 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { 1909 u32 offset = MPTCP_SKB_CB(skb)->offset; 1910 u32 data_len = skb->len - offset; 1911 u32 count = min_t(size_t, len - copied, data_len); 1912 int err; 1913 1914 if (!(flags & MSG_TRUNC)) { 1915 err = skb_copy_datagram_msg(skb, offset, msg, count); 1916 if (unlikely(err < 0)) { 1917 if (!copied) 1918 return err; 1919 break; 1920 } 1921 } 1922 1923 if (MPTCP_SKB_CB(skb)->has_rxtstamp) { 1924 tcp_update_recv_tstamps(skb, tss); 1925 *cmsg_flags |= MPTCP_CMSG_TS; 1926 } 1927 1928 copied += count; 1929 1930 if (count < data_len) { 1931 if (!(flags & MSG_PEEK)) { 1932 MPTCP_SKB_CB(skb)->offset += count; 1933 MPTCP_SKB_CB(skb)->map_seq += count; 1934 } 1935 break; 1936 } 1937 1938 if (!(flags & MSG_PEEK)) { 1939 /* we will bulk release the skb memory later */ 1940 skb->destructor = NULL; 1941 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); 1942 __skb_unlink(skb, &msk->receive_queue); 1943 __kfree_skb(skb); 1944 } 1945 1946 if (copied >= len) 1947 break; 1948 } 1949 1950 return copied; 1951 } 1952 1953 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1954 * 1955 * Only difference: Use highest rtt estimate of the subflows in use. 1956 */ 1957 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1958 { 1959 struct mptcp_subflow_context *subflow; 1960 struct sock *sk = (struct sock *)msk; 1961 u8 scaling_ratio = U8_MAX; 1962 u32 time, advmss = 1; 1963 u64 rtt_us, mstamp; 1964 1965 msk_owned_by_me(msk); 1966 1967 if (copied <= 0) 1968 return; 1969 1970 if (!msk->rcvspace_init) 1971 mptcp_rcv_space_init(msk, msk->first); 1972 1973 msk->rcvq_space.copied += copied; 1974 1975 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1976 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1977 1978 rtt_us = msk->rcvq_space.rtt_us; 1979 if (rtt_us && time < (rtt_us >> 3)) 1980 return; 1981 1982 rtt_us = 0; 1983 mptcp_for_each_subflow(msk, subflow) { 1984 const struct tcp_sock *tp; 1985 u64 sf_rtt_us; 1986 u32 sf_advmss; 1987 1988 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1989 1990 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1991 sf_advmss = READ_ONCE(tp->advmss); 1992 1993 rtt_us = max(sf_rtt_us, rtt_us); 1994 advmss = max(sf_advmss, advmss); 1995 scaling_ratio = min(tp->scaling_ratio, scaling_ratio); 1996 } 1997 1998 msk->rcvq_space.rtt_us = rtt_us; 1999 msk->scaling_ratio = scaling_ratio; 2000 if (time < (rtt_us >> 3) || rtt_us == 0) 2001 return; 2002 2003 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 2004 goto new_measure; 2005 2006 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && 2007 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 2008 u64 rcvwin, grow; 2009 int rcvbuf; 2010 2011 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 2012 2013 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 2014 2015 do_div(grow, msk->rcvq_space.space); 2016 rcvwin += (grow << 1); 2017 2018 rcvbuf = min_t(u64, __tcp_space_from_win(scaling_ratio, rcvwin), 2019 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); 2020 2021 if (rcvbuf > sk->sk_rcvbuf) { 2022 u32 window_clamp; 2023 2024 window_clamp = __tcp_win_from_space(scaling_ratio, rcvbuf); 2025 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 2026 2027 /* Make subflows follow along. If we do not do this, we 2028 * get drops at subflow level if skbs can't be moved to 2029 * the mptcp rx queue fast enough (announced rcv_win can 2030 * exceed ssk->sk_rcvbuf). 2031 */ 2032 mptcp_for_each_subflow(msk, subflow) { 2033 struct sock *ssk; 2034 bool slow; 2035 2036 ssk = mptcp_subflow_tcp_sock(subflow); 2037 slow = lock_sock_fast(ssk); 2038 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 2039 tcp_sk(ssk)->window_clamp = window_clamp; 2040 tcp_cleanup_rbuf(ssk, 1); 2041 unlock_sock_fast(ssk, slow); 2042 } 2043 } 2044 } 2045 2046 msk->rcvq_space.space = msk->rcvq_space.copied; 2047 new_measure: 2048 msk->rcvq_space.copied = 0; 2049 msk->rcvq_space.time = mstamp; 2050 } 2051 2052 static void __mptcp_update_rmem(struct sock *sk) 2053 { 2054 struct mptcp_sock *msk = mptcp_sk(sk); 2055 2056 if (!msk->rmem_released) 2057 return; 2058 2059 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); 2060 mptcp_rmem_uncharge(sk, msk->rmem_released); 2061 WRITE_ONCE(msk->rmem_released, 0); 2062 } 2063 2064 static void __mptcp_splice_receive_queue(struct sock *sk) 2065 { 2066 struct mptcp_sock *msk = mptcp_sk(sk); 2067 2068 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); 2069 } 2070 2071 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 2072 { 2073 struct sock *sk = (struct sock *)msk; 2074 unsigned int moved = 0; 2075 bool ret, done; 2076 2077 do { 2078 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 2079 bool slowpath; 2080 2081 /* we can have data pending in the subflows only if the msk 2082 * receive buffer was full at subflow_data_ready() time, 2083 * that is an unlikely slow path. 2084 */ 2085 if (likely(!ssk)) 2086 break; 2087 2088 slowpath = lock_sock_fast(ssk); 2089 mptcp_data_lock(sk); 2090 __mptcp_update_rmem(sk); 2091 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 2092 mptcp_data_unlock(sk); 2093 2094 if (unlikely(ssk->sk_err)) 2095 __mptcp_error_report(sk); 2096 unlock_sock_fast(ssk, slowpath); 2097 } while (!done); 2098 2099 /* acquire the data lock only if some input data is pending */ 2100 ret = moved > 0; 2101 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || 2102 !skb_queue_empty_lockless(&sk->sk_receive_queue)) { 2103 mptcp_data_lock(sk); 2104 __mptcp_update_rmem(sk); 2105 ret |= __mptcp_ofo_queue(msk); 2106 __mptcp_splice_receive_queue(sk); 2107 mptcp_data_unlock(sk); 2108 } 2109 if (ret) 2110 mptcp_check_data_fin((struct sock *)msk); 2111 return !skb_queue_empty(&msk->receive_queue); 2112 } 2113 2114 static unsigned int mptcp_inq_hint(const struct sock *sk) 2115 { 2116 const struct mptcp_sock *msk = mptcp_sk(sk); 2117 const struct sk_buff *skb; 2118 2119 skb = skb_peek(&msk->receive_queue); 2120 if (skb) { 2121 u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 2122 2123 if (hint_val >= INT_MAX) 2124 return INT_MAX; 2125 2126 return (unsigned int)hint_val; 2127 } 2128 2129 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 2130 return 1; 2131 2132 return 0; 2133 } 2134 2135 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 2136 int flags, int *addr_len) 2137 { 2138 struct mptcp_sock *msk = mptcp_sk(sk); 2139 struct scm_timestamping_internal tss; 2140 int copied = 0, cmsg_flags = 0; 2141 int target; 2142 long timeo; 2143 2144 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ 2145 if (unlikely(flags & MSG_ERRQUEUE)) 2146 return inet_recv_error(sk, msg, len, addr_len); 2147 2148 lock_sock(sk); 2149 if (unlikely(sk->sk_state == TCP_LISTEN)) { 2150 copied = -ENOTCONN; 2151 goto out_err; 2152 } 2153 2154 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 2155 2156 len = min_t(size_t, len, INT_MAX); 2157 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 2158 2159 if (unlikely(msk->recvmsg_inq)) 2160 cmsg_flags = MPTCP_CMSG_INQ; 2161 2162 while (copied < len) { 2163 int bytes_read; 2164 2165 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); 2166 if (unlikely(bytes_read < 0)) { 2167 if (!copied) 2168 copied = bytes_read; 2169 goto out_err; 2170 } 2171 2172 copied += bytes_read; 2173 2174 /* be sure to advertise window change */ 2175 mptcp_cleanup_rbuf(msk); 2176 2177 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) 2178 continue; 2179 2180 /* only the master socket status is relevant here. The exit 2181 * conditions mirror closely tcp_recvmsg() 2182 */ 2183 if (copied >= target) 2184 break; 2185 2186 if (copied) { 2187 if (sk->sk_err || 2188 sk->sk_state == TCP_CLOSE || 2189 (sk->sk_shutdown & RCV_SHUTDOWN) || 2190 !timeo || 2191 signal_pending(current)) 2192 break; 2193 } else { 2194 if (sk->sk_err) { 2195 copied = sock_error(sk); 2196 break; 2197 } 2198 2199 if (sk->sk_shutdown & RCV_SHUTDOWN) { 2200 /* race breaker: the shutdown could be after the 2201 * previous receive queue check 2202 */ 2203 if (__mptcp_move_skbs(msk)) 2204 continue; 2205 break; 2206 } 2207 2208 if (sk->sk_state == TCP_CLOSE) { 2209 copied = -ENOTCONN; 2210 break; 2211 } 2212 2213 if (!timeo) { 2214 copied = -EAGAIN; 2215 break; 2216 } 2217 2218 if (signal_pending(current)) { 2219 copied = sock_intr_errno(timeo); 2220 break; 2221 } 2222 } 2223 2224 pr_debug("block timeout %ld", timeo); 2225 sk_wait_data(sk, &timeo, NULL); 2226 } 2227 2228 out_err: 2229 if (cmsg_flags && copied >= 0) { 2230 if (cmsg_flags & MPTCP_CMSG_TS) 2231 tcp_recv_timestamp(msg, sk, &tss); 2232 2233 if (cmsg_flags & MPTCP_CMSG_INQ) { 2234 unsigned int inq = mptcp_inq_hint(sk); 2235 2236 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq); 2237 } 2238 } 2239 2240 pr_debug("msk=%p rx queue empty=%d:%d copied=%d", 2241 msk, skb_queue_empty_lockless(&sk->sk_receive_queue), 2242 skb_queue_empty(&msk->receive_queue), copied); 2243 if (!(flags & MSG_PEEK)) 2244 mptcp_rcv_space_adjust(msk, copied); 2245 2246 release_sock(sk); 2247 return copied; 2248 } 2249 2250 static void mptcp_retransmit_timer(struct timer_list *t) 2251 { 2252 struct inet_connection_sock *icsk = from_timer(icsk, t, 2253 icsk_retransmit_timer); 2254 struct sock *sk = &icsk->icsk_inet.sk; 2255 struct mptcp_sock *msk = mptcp_sk(sk); 2256 2257 bh_lock_sock(sk); 2258 if (!sock_owned_by_user(sk)) { 2259 /* we need a process context to retransmit */ 2260 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) 2261 mptcp_schedule_work(sk); 2262 } else { 2263 /* delegate our work to tcp_release_cb() */ 2264 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags); 2265 } 2266 bh_unlock_sock(sk); 2267 sock_put(sk); 2268 } 2269 2270 static void mptcp_tout_timer(struct timer_list *t) 2271 { 2272 struct sock *sk = from_timer(sk, t, sk_timer); 2273 2274 mptcp_schedule_work(sk); 2275 sock_put(sk); 2276 } 2277 2278 /* Find an idle subflow. Return NULL if there is unacked data at tcp 2279 * level. 2280 * 2281 * A backup subflow is returned only if that is the only kind available. 2282 */ 2283 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk) 2284 { 2285 struct sock *backup = NULL, *pick = NULL; 2286 struct mptcp_subflow_context *subflow; 2287 int min_stale_count = INT_MAX; 2288 2289 mptcp_for_each_subflow(msk, subflow) { 2290 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2291 2292 if (!__mptcp_subflow_active(subflow)) 2293 continue; 2294 2295 /* still data outstanding at TCP level? skip this */ 2296 if (!tcp_rtx_and_write_queues_empty(ssk)) { 2297 mptcp_pm_subflow_chk_stale(msk, ssk); 2298 min_stale_count = min_t(int, min_stale_count, subflow->stale_count); 2299 continue; 2300 } 2301 2302 if (subflow->backup) { 2303 if (!backup) 2304 backup = ssk; 2305 continue; 2306 } 2307 2308 if (!pick) 2309 pick = ssk; 2310 } 2311 2312 if (pick) 2313 return pick; 2314 2315 /* use backup only if there are no progresses anywhere */ 2316 return min_stale_count > 1 ? backup : NULL; 2317 } 2318 2319 bool __mptcp_retransmit_pending_data(struct sock *sk) 2320 { 2321 struct mptcp_data_frag *cur, *rtx_head; 2322 struct mptcp_sock *msk = mptcp_sk(sk); 2323 2324 if (__mptcp_check_fallback(msk)) 2325 return false; 2326 2327 /* the closing socket has some data untransmitted and/or unacked: 2328 * some data in the mptcp rtx queue has not really xmitted yet. 2329 * keep it simple and re-inject the whole mptcp level rtx queue 2330 */ 2331 mptcp_data_lock(sk); 2332 __mptcp_clean_una_wakeup(sk); 2333 rtx_head = mptcp_rtx_head(sk); 2334 if (!rtx_head) { 2335 mptcp_data_unlock(sk); 2336 return false; 2337 } 2338 2339 msk->recovery_snd_nxt = msk->snd_nxt; 2340 msk->recovery = true; 2341 mptcp_data_unlock(sk); 2342 2343 msk->first_pending = rtx_head; 2344 msk->snd_burst = 0; 2345 2346 /* be sure to clear the "sent status" on all re-injected fragments */ 2347 list_for_each_entry(cur, &msk->rtx_queue, list) { 2348 if (!cur->already_sent) 2349 break; 2350 cur->already_sent = 0; 2351 } 2352 2353 return true; 2354 } 2355 2356 /* flags for __mptcp_close_ssk() */ 2357 #define MPTCP_CF_PUSH BIT(1) 2358 #define MPTCP_CF_FASTCLOSE BIT(2) 2359 2360 /* be sure to send a reset only if the caller asked for it, also 2361 * clean completely the subflow status when the subflow reaches 2362 * TCP_CLOSE state 2363 */ 2364 static void __mptcp_subflow_disconnect(struct sock *ssk, 2365 struct mptcp_subflow_context *subflow, 2366 unsigned int flags) 2367 { 2368 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || 2369 (flags & MPTCP_CF_FASTCLOSE)) { 2370 /* The MPTCP code never wait on the subflow sockets, TCP-level 2371 * disconnect should never fail 2372 */ 2373 WARN_ON_ONCE(tcp_disconnect(ssk, 0)); 2374 mptcp_subflow_ctx_reset(subflow); 2375 } else { 2376 tcp_shutdown(ssk, SEND_SHUTDOWN); 2377 } 2378 } 2379 2380 /* subflow sockets can be either outgoing (connect) or incoming 2381 * (accept). 2382 * 2383 * Outgoing subflows use in-kernel sockets. 2384 * Incoming subflows do not have their own 'struct socket' allocated, 2385 * so we need to use tcp_close() after detaching them from the mptcp 2386 * parent socket. 2387 */ 2388 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2389 struct mptcp_subflow_context *subflow, 2390 unsigned int flags) 2391 { 2392 struct mptcp_sock *msk = mptcp_sk(sk); 2393 bool dispose_it, need_push = false; 2394 2395 /* If the first subflow moved to a close state before accept, e.g. due 2396 * to an incoming reset or listener shutdown, the subflow socket is 2397 * already deleted by inet_child_forget() and the mptcp socket can't 2398 * survive too. 2399 */ 2400 if (msk->in_accept_queue && msk->first == ssk && 2401 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) { 2402 /* ensure later check in mptcp_worker() will dispose the msk */ 2403 mptcp_set_close_tout(sk, tcp_jiffies32 - (TCP_TIMEWAIT_LEN + 1)); 2404 sock_set_flag(sk, SOCK_DEAD); 2405 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2406 mptcp_subflow_drop_ctx(ssk); 2407 goto out_release; 2408 } 2409 2410 dispose_it = msk->free_first || ssk != msk->first; 2411 if (dispose_it) 2412 list_del(&subflow->node); 2413 2414 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2415 2416 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) { 2417 /* be sure to force the tcp_close path 2418 * to generate the egress reset 2419 */ 2420 ssk->sk_lingertime = 0; 2421 sock_set_flag(ssk, SOCK_LINGER); 2422 subflow->send_fastclose = 1; 2423 } 2424 2425 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); 2426 if (!dispose_it) { 2427 __mptcp_subflow_disconnect(ssk, subflow, flags); 2428 release_sock(ssk); 2429 2430 goto out; 2431 } 2432 2433 subflow->disposable = 1; 2434 2435 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops 2436 * the ssk has been already destroyed, we just need to release the 2437 * reference owned by msk; 2438 */ 2439 if (!inet_csk(ssk)->icsk_ulp_ops) { 2440 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD)); 2441 kfree_rcu(subflow, rcu); 2442 } else { 2443 /* otherwise tcp will dispose of the ssk and subflow ctx */ 2444 __tcp_close(ssk, 0); 2445 2446 /* close acquired an extra ref */ 2447 __sock_put(ssk); 2448 } 2449 2450 out_release: 2451 __mptcp_subflow_error_report(sk, ssk); 2452 release_sock(ssk); 2453 2454 sock_put(ssk); 2455 2456 if (ssk == msk->first) 2457 WRITE_ONCE(msk->first, NULL); 2458 2459 out: 2460 __mptcp_sync_sndbuf(sk); 2461 if (need_push) 2462 __mptcp_push_pending(sk, 0); 2463 2464 /* Catch every 'all subflows closed' scenario, including peers silently 2465 * closing them, e.g. due to timeout. 2466 * For established sockets, allow an additional timeout before closing, 2467 * as the protocol can still create more subflows. 2468 */ 2469 if (list_is_singular(&msk->conn_list) && msk->first && 2470 inet_sk_state_load(msk->first) == TCP_CLOSE) { 2471 if (sk->sk_state != TCP_ESTABLISHED || 2472 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) { 2473 inet_sk_state_store(sk, TCP_CLOSE); 2474 mptcp_close_wake_up(sk); 2475 } else { 2476 mptcp_start_tout_timer(sk); 2477 } 2478 } 2479 } 2480 2481 void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2482 struct mptcp_subflow_context *subflow) 2483 { 2484 if (sk->sk_state == TCP_ESTABLISHED) 2485 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); 2486 2487 /* subflow aborted before reaching the fully_established status 2488 * attempt the creation of the next subflow 2489 */ 2490 mptcp_pm_subflow_check_next(mptcp_sk(sk), ssk, subflow); 2491 2492 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH); 2493 } 2494 2495 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 2496 { 2497 return 0; 2498 } 2499 2500 static void __mptcp_close_subflow(struct sock *sk) 2501 { 2502 struct mptcp_subflow_context *subflow, *tmp; 2503 struct mptcp_sock *msk = mptcp_sk(sk); 2504 2505 might_sleep(); 2506 2507 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2508 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2509 2510 if (inet_sk_state_load(ssk) != TCP_CLOSE) 2511 continue; 2512 2513 /* 'subflow_data_ready' will re-sched once rx queue is empty */ 2514 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) 2515 continue; 2516 2517 mptcp_close_ssk(sk, ssk, subflow); 2518 } 2519 2520 } 2521 2522 static bool mptcp_close_tout_expired(const struct sock *sk) 2523 { 2524 if (!inet_csk(sk)->icsk_mtup.probe_timestamp || 2525 sk->sk_state == TCP_CLOSE) 2526 return false; 2527 2528 return time_after32(tcp_jiffies32, 2529 inet_csk(sk)->icsk_mtup.probe_timestamp + TCP_TIMEWAIT_LEN); 2530 } 2531 2532 static void mptcp_check_fastclose(struct mptcp_sock *msk) 2533 { 2534 struct mptcp_subflow_context *subflow, *tmp; 2535 struct sock *sk = (struct sock *)msk; 2536 2537 if (likely(!READ_ONCE(msk->rcv_fastclose))) 2538 return; 2539 2540 mptcp_token_destroy(msk); 2541 2542 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2543 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2544 bool slow; 2545 2546 slow = lock_sock_fast(tcp_sk); 2547 if (tcp_sk->sk_state != TCP_CLOSE) { 2548 tcp_send_active_reset(tcp_sk, GFP_ATOMIC); 2549 tcp_set_state(tcp_sk, TCP_CLOSE); 2550 } 2551 unlock_sock_fast(tcp_sk, slow); 2552 } 2553 2554 /* Mirror the tcp_reset() error propagation */ 2555 switch (sk->sk_state) { 2556 case TCP_SYN_SENT: 2557 WRITE_ONCE(sk->sk_err, ECONNREFUSED); 2558 break; 2559 case TCP_CLOSE_WAIT: 2560 WRITE_ONCE(sk->sk_err, EPIPE); 2561 break; 2562 case TCP_CLOSE: 2563 return; 2564 default: 2565 WRITE_ONCE(sk->sk_err, ECONNRESET); 2566 } 2567 2568 inet_sk_state_store(sk, TCP_CLOSE); 2569 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); 2570 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 2571 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); 2572 2573 /* the calling mptcp_worker will properly destroy the socket */ 2574 if (sock_flag(sk, SOCK_DEAD)) 2575 return; 2576 2577 sk->sk_state_change(sk); 2578 sk_error_report(sk); 2579 } 2580 2581 static void __mptcp_retrans(struct sock *sk) 2582 { 2583 struct mptcp_sock *msk = mptcp_sk(sk); 2584 struct mptcp_subflow_context *subflow; 2585 struct mptcp_sendmsg_info info = {}; 2586 struct mptcp_data_frag *dfrag; 2587 struct sock *ssk; 2588 int ret, err; 2589 u16 len = 0; 2590 2591 mptcp_clean_una_wakeup(sk); 2592 2593 /* first check ssk: need to kick "stale" logic */ 2594 err = mptcp_sched_get_retrans(msk); 2595 dfrag = mptcp_rtx_head(sk); 2596 if (!dfrag) { 2597 if (mptcp_data_fin_enabled(msk)) { 2598 struct inet_connection_sock *icsk = inet_csk(sk); 2599 2600 icsk->icsk_retransmits++; 2601 mptcp_set_datafin_timeout(sk); 2602 mptcp_send_ack(msk); 2603 2604 goto reset_timer; 2605 } 2606 2607 if (!mptcp_send_head(sk)) 2608 return; 2609 2610 goto reset_timer; 2611 } 2612 2613 if (err) 2614 goto reset_timer; 2615 2616 mptcp_for_each_subflow(msk, subflow) { 2617 if (READ_ONCE(subflow->scheduled)) { 2618 u16 copied = 0; 2619 2620 mptcp_subflow_set_scheduled(subflow, false); 2621 2622 ssk = mptcp_subflow_tcp_sock(subflow); 2623 2624 lock_sock(ssk); 2625 2626 /* limit retransmission to the bytes already sent on some subflows */ 2627 info.sent = 0; 2628 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : 2629 dfrag->already_sent; 2630 while (info.sent < info.limit) { 2631 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 2632 if (ret <= 0) 2633 break; 2634 2635 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 2636 copied += ret; 2637 info.sent += ret; 2638 } 2639 if (copied) { 2640 len = max(copied, len); 2641 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 2642 info.size_goal); 2643 WRITE_ONCE(msk->allow_infinite_fallback, false); 2644 } 2645 2646 release_sock(ssk); 2647 } 2648 } 2649 2650 msk->bytes_retrans += len; 2651 dfrag->already_sent = max(dfrag->already_sent, len); 2652 2653 reset_timer: 2654 mptcp_check_and_set_pending(sk); 2655 2656 if (!mptcp_rtx_timer_pending(sk)) 2657 mptcp_reset_rtx_timer(sk); 2658 } 2659 2660 /* schedule the timeout timer for the relevant event: either close timeout 2661 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one 2662 */ 2663 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) 2664 { 2665 struct sock *sk = (struct sock *)msk; 2666 unsigned long timeout, close_timeout; 2667 2668 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) 2669 return; 2670 2671 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + 2672 TCP_TIMEWAIT_LEN; 2673 2674 /* the close timeout takes precedence on the fail one, and here at least one of 2675 * them is active 2676 */ 2677 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout; 2678 2679 sk_reset_timer(sk, &sk->sk_timer, timeout); 2680 } 2681 2682 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) 2683 { 2684 struct sock *ssk = msk->first; 2685 bool slow; 2686 2687 if (!ssk) 2688 return; 2689 2690 pr_debug("MP_FAIL doesn't respond, reset the subflow"); 2691 2692 slow = lock_sock_fast(ssk); 2693 mptcp_subflow_reset(ssk); 2694 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0); 2695 unlock_sock_fast(ssk, slow); 2696 } 2697 2698 static void mptcp_do_fastclose(struct sock *sk) 2699 { 2700 struct mptcp_subflow_context *subflow, *tmp; 2701 struct mptcp_sock *msk = mptcp_sk(sk); 2702 2703 inet_sk_state_store(sk, TCP_CLOSE); 2704 mptcp_for_each_subflow_safe(msk, subflow, tmp) 2705 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), 2706 subflow, MPTCP_CF_FASTCLOSE); 2707 } 2708 2709 static void mptcp_worker(struct work_struct *work) 2710 { 2711 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 2712 struct sock *sk = (struct sock *)msk; 2713 unsigned long fail_tout; 2714 int state; 2715 2716 lock_sock(sk); 2717 state = sk->sk_state; 2718 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN))) 2719 goto unlock; 2720 2721 mptcp_check_fastclose(msk); 2722 2723 mptcp_pm_nl_work(msk); 2724 2725 mptcp_check_send_data_fin(sk); 2726 mptcp_check_data_fin_ack(sk); 2727 mptcp_check_data_fin(sk); 2728 2729 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) 2730 __mptcp_close_subflow(sk); 2731 2732 if (mptcp_close_tout_expired(sk)) { 2733 mptcp_do_fastclose(sk); 2734 mptcp_close_wake_up(sk); 2735 } 2736 2737 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) { 2738 __mptcp_destroy_sock(sk); 2739 goto unlock; 2740 } 2741 2742 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 2743 __mptcp_retrans(sk); 2744 2745 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0; 2746 if (fail_tout && time_after(jiffies, fail_tout)) 2747 mptcp_mp_fail_no_response(msk); 2748 2749 unlock: 2750 release_sock(sk); 2751 sock_put(sk); 2752 } 2753 2754 static void __mptcp_init_sock(struct sock *sk) 2755 { 2756 struct mptcp_sock *msk = mptcp_sk(sk); 2757 2758 INIT_LIST_HEAD(&msk->conn_list); 2759 INIT_LIST_HEAD(&msk->join_list); 2760 INIT_LIST_HEAD(&msk->rtx_queue); 2761 INIT_WORK(&msk->work, mptcp_worker); 2762 __skb_queue_head_init(&msk->receive_queue); 2763 msk->out_of_order_queue = RB_ROOT; 2764 msk->first_pending = NULL; 2765 msk->rmem_fwd_alloc = 0; 2766 WRITE_ONCE(msk->rmem_released, 0); 2767 msk->timer_ival = TCP_RTO_MIN; 2768 2769 WRITE_ONCE(msk->first, NULL); 2770 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 2771 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 2772 WRITE_ONCE(msk->allow_infinite_fallback, true); 2773 msk->recovery = false; 2774 msk->subflow_id = 1; 2775 2776 mptcp_pm_data_init(msk); 2777 2778 /* re-use the csk retrans timer for MPTCP-level retrans */ 2779 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 2780 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0); 2781 } 2782 2783 static void mptcp_ca_reset(struct sock *sk) 2784 { 2785 struct inet_connection_sock *icsk = inet_csk(sk); 2786 2787 tcp_assign_congestion_control(sk); 2788 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); 2789 2790 /* no need to keep a reference to the ops, the name will suffice */ 2791 tcp_cleanup_congestion_control(sk); 2792 icsk->icsk_ca_ops = NULL; 2793 } 2794 2795 static int mptcp_init_sock(struct sock *sk) 2796 { 2797 struct net *net = sock_net(sk); 2798 int ret; 2799 2800 __mptcp_init_sock(sk); 2801 2802 if (!mptcp_is_enabled(net)) 2803 return -ENOPROTOOPT; 2804 2805 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 2806 return -ENOMEM; 2807 2808 ret = mptcp_init_sched(mptcp_sk(sk), 2809 mptcp_sched_find(mptcp_get_scheduler(net))); 2810 if (ret) 2811 return ret; 2812 2813 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); 2814 2815 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will 2816 * propagate the correct value 2817 */ 2818 mptcp_ca_reset(sk); 2819 2820 sk_sockets_allocated_inc(sk); 2821 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]); 2822 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]); 2823 2824 return 0; 2825 } 2826 2827 static void __mptcp_clear_xmit(struct sock *sk) 2828 { 2829 struct mptcp_sock *msk = mptcp_sk(sk); 2830 struct mptcp_data_frag *dtmp, *dfrag; 2831 2832 WRITE_ONCE(msk->first_pending, NULL); 2833 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 2834 dfrag_clear(sk, dfrag); 2835 } 2836 2837 void mptcp_cancel_work(struct sock *sk) 2838 { 2839 struct mptcp_sock *msk = mptcp_sk(sk); 2840 2841 if (cancel_work_sync(&msk->work)) 2842 __sock_put(sk); 2843 } 2844 2845 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 2846 { 2847 lock_sock(ssk); 2848 2849 switch (ssk->sk_state) { 2850 case TCP_LISTEN: 2851 if (!(how & RCV_SHUTDOWN)) 2852 break; 2853 fallthrough; 2854 case TCP_SYN_SENT: 2855 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK)); 2856 break; 2857 default: 2858 if (__mptcp_check_fallback(mptcp_sk(sk))) { 2859 pr_debug("Fallback"); 2860 ssk->sk_shutdown |= how; 2861 tcp_shutdown(ssk, how); 2862 2863 /* simulate the data_fin ack reception to let the state 2864 * machine move forward 2865 */ 2866 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt); 2867 mptcp_schedule_work(sk); 2868 } else { 2869 pr_debug("Sending DATA_FIN on subflow %p", ssk); 2870 tcp_send_ack(ssk); 2871 if (!mptcp_rtx_timer_pending(sk)) 2872 mptcp_reset_rtx_timer(sk); 2873 } 2874 break; 2875 } 2876 2877 release_sock(ssk); 2878 } 2879 2880 static const unsigned char new_state[16] = { 2881 /* current state: new state: action: */ 2882 [0 /* (Invalid) */] = TCP_CLOSE, 2883 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2884 [TCP_SYN_SENT] = TCP_CLOSE, 2885 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2886 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 2887 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 2888 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 2889 [TCP_CLOSE] = TCP_CLOSE, 2890 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 2891 [TCP_LAST_ACK] = TCP_LAST_ACK, 2892 [TCP_LISTEN] = TCP_CLOSE, 2893 [TCP_CLOSING] = TCP_CLOSING, 2894 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 2895 }; 2896 2897 static int mptcp_close_state(struct sock *sk) 2898 { 2899 int next = (int)new_state[sk->sk_state]; 2900 int ns = next & TCP_STATE_MASK; 2901 2902 inet_sk_state_store(sk, ns); 2903 2904 return next & TCP_ACTION_FIN; 2905 } 2906 2907 static void mptcp_check_send_data_fin(struct sock *sk) 2908 { 2909 struct mptcp_subflow_context *subflow; 2910 struct mptcp_sock *msk = mptcp_sk(sk); 2911 2912 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", 2913 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), 2914 msk->snd_nxt, msk->write_seq); 2915 2916 /* we still need to enqueue subflows or not really shutting down, 2917 * skip this 2918 */ 2919 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || 2920 mptcp_send_head(sk)) 2921 return; 2922 2923 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2924 2925 mptcp_for_each_subflow(msk, subflow) { 2926 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2927 2928 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); 2929 } 2930 } 2931 2932 static void __mptcp_wr_shutdown(struct sock *sk) 2933 { 2934 struct mptcp_sock *msk = mptcp_sk(sk); 2935 2936 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", 2937 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, 2938 !!mptcp_send_head(sk)); 2939 2940 /* will be ignored by fallback sockets */ 2941 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2942 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2943 2944 mptcp_check_send_data_fin(sk); 2945 } 2946 2947 static void __mptcp_destroy_sock(struct sock *sk) 2948 { 2949 struct mptcp_sock *msk = mptcp_sk(sk); 2950 2951 pr_debug("msk=%p", msk); 2952 2953 might_sleep(); 2954 2955 mptcp_stop_rtx_timer(sk); 2956 sk_stop_timer(sk, &sk->sk_timer); 2957 msk->pm.status = 0; 2958 mptcp_release_sched(msk); 2959 2960 sk->sk_prot->destroy(sk); 2961 2962 WARN_ON_ONCE(msk->rmem_fwd_alloc); 2963 WARN_ON_ONCE(msk->rmem_released); 2964 sk_stream_kill_queues(sk); 2965 xfrm_sk_free_policy(sk); 2966 2967 sock_put(sk); 2968 } 2969 2970 void __mptcp_unaccepted_force_close(struct sock *sk) 2971 { 2972 sock_set_flag(sk, SOCK_DEAD); 2973 mptcp_do_fastclose(sk); 2974 __mptcp_destroy_sock(sk); 2975 } 2976 2977 static __poll_t mptcp_check_readable(struct mptcp_sock *msk) 2978 { 2979 /* Concurrent splices from sk_receive_queue into receive_queue will 2980 * always show at least one non-empty queue when checked in this order. 2981 */ 2982 if (skb_queue_empty_lockless(&((struct sock *)msk)->sk_receive_queue) && 2983 skb_queue_empty_lockless(&msk->receive_queue)) 2984 return 0; 2985 2986 return EPOLLIN | EPOLLRDNORM; 2987 } 2988 2989 static void mptcp_check_listen_stop(struct sock *sk) 2990 { 2991 struct sock *ssk; 2992 2993 if (inet_sk_state_load(sk) != TCP_LISTEN) 2994 return; 2995 2996 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 2997 ssk = mptcp_sk(sk)->first; 2998 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN)) 2999 return; 3000 3001 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 3002 tcp_set_state(ssk, TCP_CLOSE); 3003 mptcp_subflow_queue_clean(sk, ssk); 3004 inet_csk_listen_stop(ssk); 3005 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED); 3006 release_sock(ssk); 3007 } 3008 3009 bool __mptcp_close(struct sock *sk, long timeout) 3010 { 3011 struct mptcp_subflow_context *subflow; 3012 struct mptcp_sock *msk = mptcp_sk(sk); 3013 bool do_cancel_work = false; 3014 int subflows_alive = 0; 3015 3016 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); 3017 3018 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { 3019 mptcp_check_listen_stop(sk); 3020 inet_sk_state_store(sk, TCP_CLOSE); 3021 goto cleanup; 3022 } 3023 3024 if (mptcp_check_readable(msk) || timeout < 0) { 3025 /* If the msk has read data, or the caller explicitly ask it, 3026 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose 3027 */ 3028 mptcp_do_fastclose(sk); 3029 timeout = 0; 3030 } else if (mptcp_close_state(sk)) { 3031 __mptcp_wr_shutdown(sk); 3032 } 3033 3034 sk_stream_wait_close(sk, timeout); 3035 3036 cleanup: 3037 /* orphan all the subflows */ 3038 mptcp_for_each_subflow(msk, subflow) { 3039 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3040 bool slow = lock_sock_fast_nested(ssk); 3041 3042 subflows_alive += ssk->sk_state != TCP_CLOSE; 3043 3044 /* since the close timeout takes precedence on the fail one, 3045 * cancel the latter 3046 */ 3047 if (ssk == msk->first) 3048 subflow->fail_tout = 0; 3049 3050 /* detach from the parent socket, but allow data_ready to 3051 * push incoming data into the mptcp stack, to properly ack it 3052 */ 3053 ssk->sk_socket = NULL; 3054 ssk->sk_wq = NULL; 3055 unlock_sock_fast(ssk, slow); 3056 } 3057 sock_orphan(sk); 3058 3059 /* all the subflows are closed, only timeout can change the msk 3060 * state, let's not keep resources busy for no reasons 3061 */ 3062 if (subflows_alive == 0) 3063 inet_sk_state_store(sk, TCP_CLOSE); 3064 3065 sock_hold(sk); 3066 pr_debug("msk=%p state=%d", sk, sk->sk_state); 3067 if (msk->token) 3068 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 3069 3070 if (sk->sk_state == TCP_CLOSE) { 3071 __mptcp_destroy_sock(sk); 3072 do_cancel_work = true; 3073 } else { 3074 mptcp_start_tout_timer(sk); 3075 } 3076 3077 return do_cancel_work; 3078 } 3079 3080 static void mptcp_close(struct sock *sk, long timeout) 3081 { 3082 bool do_cancel_work; 3083 3084 lock_sock(sk); 3085 3086 do_cancel_work = __mptcp_close(sk, timeout); 3087 release_sock(sk); 3088 if (do_cancel_work) 3089 mptcp_cancel_work(sk); 3090 3091 sock_put(sk); 3092 } 3093 3094 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 3095 { 3096 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3097 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 3098 struct ipv6_pinfo *msk6 = inet6_sk(msk); 3099 3100 msk->sk_v6_daddr = ssk->sk_v6_daddr; 3101 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 3102 3103 if (msk6 && ssk6) { 3104 msk6->saddr = ssk6->saddr; 3105 msk6->flow_label = ssk6->flow_label; 3106 } 3107 #endif 3108 3109 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 3110 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 3111 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 3112 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 3113 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 3114 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 3115 } 3116 3117 static int mptcp_disconnect(struct sock *sk, int flags) 3118 { 3119 struct mptcp_sock *msk = mptcp_sk(sk); 3120 3121 /* We are on the fastopen error path. We can't call straight into the 3122 * subflows cleanup code due to lock nesting (we are already under 3123 * msk->firstsocket lock). 3124 */ 3125 if (msk->fastopening) 3126 return -EBUSY; 3127 3128 mptcp_check_listen_stop(sk); 3129 inet_sk_state_store(sk, TCP_CLOSE); 3130 3131 mptcp_stop_rtx_timer(sk); 3132 mptcp_stop_tout_timer(sk); 3133 3134 if (msk->token) 3135 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 3136 3137 /* msk->subflow is still intact, the following will not free the first 3138 * subflow 3139 */ 3140 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); 3141 WRITE_ONCE(msk->flags, 0); 3142 msk->cb_flags = 0; 3143 msk->recovery = false; 3144 msk->can_ack = false; 3145 msk->fully_established = false; 3146 msk->rcv_data_fin = false; 3147 msk->snd_data_fin_enable = false; 3148 msk->rcv_fastclose = false; 3149 msk->use_64bit_ack = false; 3150 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 3151 mptcp_pm_data_reset(msk); 3152 mptcp_ca_reset(sk); 3153 msk->bytes_acked = 0; 3154 msk->bytes_received = 0; 3155 msk->bytes_sent = 0; 3156 msk->bytes_retrans = 0; 3157 msk->rcvspace_init = 0; 3158 3159 WRITE_ONCE(sk->sk_shutdown, 0); 3160 sk_error_report(sk); 3161 return 0; 3162 } 3163 3164 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3165 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 3166 { 3167 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 3168 3169 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 3170 } 3171 #endif 3172 3173 struct sock *mptcp_sk_clone_init(const struct sock *sk, 3174 const struct mptcp_options_received *mp_opt, 3175 struct sock *ssk, 3176 struct request_sock *req) 3177 { 3178 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 3179 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 3180 struct mptcp_sock *msk; 3181 3182 if (!nsk) 3183 return NULL; 3184 3185 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3186 if (nsk->sk_family == AF_INET6) 3187 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 3188 #endif 3189 3190 __mptcp_init_sock(nsk); 3191 3192 msk = mptcp_sk(nsk); 3193 msk->local_key = subflow_req->local_key; 3194 msk->token = subflow_req->token; 3195 msk->in_accept_queue = 1; 3196 WRITE_ONCE(msk->fully_established, false); 3197 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) 3198 WRITE_ONCE(msk->csum_enabled, true); 3199 3200 msk->write_seq = subflow_req->idsn + 1; 3201 msk->snd_nxt = msk->write_seq; 3202 msk->snd_una = msk->write_seq; 3203 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; 3204 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; 3205 mptcp_init_sched(msk, mptcp_sk(sk)->sched); 3206 3207 /* passive msk is created after the first/MPC subflow */ 3208 msk->subflow_id = 2; 3209 3210 sock_reset_flag(nsk, SOCK_RCU_FREE); 3211 security_inet_csk_clone(nsk, req); 3212 3213 /* this can't race with mptcp_close(), as the msk is 3214 * not yet exposted to user-space 3215 */ 3216 inet_sk_state_store(nsk, TCP_ESTABLISHED); 3217 3218 /* The msk maintain a ref to each subflow in the connections list */ 3219 WRITE_ONCE(msk->first, ssk); 3220 list_add(&mptcp_subflow_ctx(ssk)->node, &msk->conn_list); 3221 sock_hold(ssk); 3222 3223 /* new mpc subflow takes ownership of the newly 3224 * created mptcp socket 3225 */ 3226 mptcp_token_accept(subflow_req, msk); 3227 3228 /* set msk addresses early to ensure mptcp_pm_get_local_id() 3229 * uses the correct data 3230 */ 3231 mptcp_copy_inaddrs(nsk, ssk); 3232 __mptcp_propagate_sndbuf(nsk, ssk); 3233 3234 mptcp_rcv_space_init(msk, ssk); 3235 bh_unlock_sock(nsk); 3236 3237 /* note: the newly allocated socket refcount is 2 now */ 3238 return nsk; 3239 } 3240 3241 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 3242 { 3243 const struct tcp_sock *tp = tcp_sk(ssk); 3244 3245 msk->rcvspace_init = 1; 3246 msk->rcvq_space.copied = 0; 3247 msk->rcvq_space.rtt_us = 0; 3248 3249 msk->rcvq_space.time = tp->tcp_mstamp; 3250 3251 /* initial rcv_space offering made to peer */ 3252 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 3253 TCP_INIT_CWND * tp->advmss); 3254 if (msk->rcvq_space.space == 0) 3255 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 3256 } 3257 3258 static struct sock *mptcp_accept(struct sock *ssk, int flags, int *err, 3259 bool kern) 3260 { 3261 struct sock *newsk; 3262 3263 pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk)); 3264 newsk = inet_csk_accept(ssk, flags, err, kern); 3265 if (!newsk) 3266 return NULL; 3267 3268 pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk)); 3269 if (sk_is_mptcp(newsk)) { 3270 struct mptcp_subflow_context *subflow; 3271 struct sock *new_mptcp_sock; 3272 3273 subflow = mptcp_subflow_ctx(newsk); 3274 new_mptcp_sock = subflow->conn; 3275 3276 /* is_mptcp should be false if subflow->conn is missing, see 3277 * subflow_syn_recv_sock() 3278 */ 3279 if (WARN_ON_ONCE(!new_mptcp_sock)) { 3280 tcp_sk(newsk)->is_mptcp = 0; 3281 goto out; 3282 } 3283 3284 newsk = new_mptcp_sock; 3285 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 3286 } else { 3287 MPTCP_INC_STATS(sock_net(ssk), 3288 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 3289 } 3290 3291 out: 3292 newsk->sk_kern_sock = kern; 3293 return newsk; 3294 } 3295 3296 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) 3297 { 3298 struct mptcp_subflow_context *subflow, *tmp; 3299 struct sock *sk = (struct sock *)msk; 3300 3301 __mptcp_clear_xmit(sk); 3302 3303 /* join list will be eventually flushed (with rst) at sock lock release time */ 3304 mptcp_for_each_subflow_safe(msk, subflow, tmp) 3305 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); 3306 3307 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ 3308 mptcp_data_lock(sk); 3309 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); 3310 __skb_queue_purge(&sk->sk_receive_queue); 3311 skb_rbtree_purge(&msk->out_of_order_queue); 3312 mptcp_data_unlock(sk); 3313 3314 /* move all the rx fwd alloc into the sk_mem_reclaim_final in 3315 * inet_sock_destruct() will dispose it 3316 */ 3317 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc); 3318 WRITE_ONCE(msk->rmem_fwd_alloc, 0); 3319 mptcp_token_destroy(msk); 3320 mptcp_pm_free_anno_list(msk); 3321 mptcp_free_local_addr_list(msk); 3322 } 3323 3324 static void mptcp_destroy(struct sock *sk) 3325 { 3326 struct mptcp_sock *msk = mptcp_sk(sk); 3327 3328 /* allow the following to close even the initial subflow */ 3329 msk->free_first = 1; 3330 mptcp_destroy_common(msk, 0); 3331 sk_sockets_allocated_dec(sk); 3332 } 3333 3334 void __mptcp_data_acked(struct sock *sk) 3335 { 3336 if (!sock_owned_by_user(sk)) 3337 __mptcp_clean_una(sk); 3338 else 3339 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags); 3340 3341 if (mptcp_pending_data_fin_ack(sk)) 3342 mptcp_schedule_work(sk); 3343 } 3344 3345 void __mptcp_check_push(struct sock *sk, struct sock *ssk) 3346 { 3347 if (!mptcp_send_head(sk)) 3348 return; 3349 3350 if (!sock_owned_by_user(sk)) 3351 __mptcp_subflow_push_pending(sk, ssk, false); 3352 else 3353 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3354 } 3355 3356 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ 3357 BIT(MPTCP_RETRANSMIT) | \ 3358 BIT(MPTCP_FLUSH_JOIN_LIST)) 3359 3360 /* processes deferred events and flush wmem */ 3361 static void mptcp_release_cb(struct sock *sk) 3362 __must_hold(&sk->sk_lock.slock) 3363 { 3364 struct mptcp_sock *msk = mptcp_sk(sk); 3365 3366 for (;;) { 3367 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED); 3368 struct list_head join_list; 3369 3370 if (!flags) 3371 break; 3372 3373 INIT_LIST_HEAD(&join_list); 3374 list_splice_init(&msk->join_list, &join_list); 3375 3376 /* the following actions acquire the subflow socket lock 3377 * 3378 * 1) can't be invoked in atomic scope 3379 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX 3380 * datapath acquires the msk socket spinlock while helding 3381 * the subflow socket lock 3382 */ 3383 msk->cb_flags &= ~flags; 3384 spin_unlock_bh(&sk->sk_lock.slock); 3385 3386 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST)) 3387 __mptcp_flush_join_list(sk, &join_list); 3388 if (flags & BIT(MPTCP_PUSH_PENDING)) 3389 __mptcp_push_pending(sk, 0); 3390 if (flags & BIT(MPTCP_RETRANSMIT)) 3391 __mptcp_retrans(sk); 3392 3393 cond_resched(); 3394 spin_lock_bh(&sk->sk_lock.slock); 3395 } 3396 3397 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags)) 3398 __mptcp_clean_una_wakeup(sk); 3399 if (unlikely(msk->cb_flags)) { 3400 /* be sure to sync the msk state before taking actions 3401 * depending on sk_state (MPTCP_ERROR_REPORT) 3402 * On sk release avoid actions depending on the first subflow 3403 */ 3404 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first) 3405 __mptcp_sync_state(sk, msk->pending_state); 3406 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags)) 3407 __mptcp_error_report(sk); 3408 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags)) 3409 __mptcp_sync_sndbuf(sk); 3410 } 3411 3412 __mptcp_update_rmem(sk); 3413 } 3414 3415 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 3416 * TCP can't schedule delack timer before the subflow is fully established. 3417 * MPTCP uses the delack timer to do 3rd ack retransmissions 3418 */ 3419 static void schedule_3rdack_retransmission(struct sock *ssk) 3420 { 3421 struct inet_connection_sock *icsk = inet_csk(ssk); 3422 struct tcp_sock *tp = tcp_sk(ssk); 3423 unsigned long timeout; 3424 3425 if (mptcp_subflow_ctx(ssk)->fully_established) 3426 return; 3427 3428 /* reschedule with a timeout above RTT, as we must look only for drop */ 3429 if (tp->srtt_us) 3430 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1)); 3431 else 3432 timeout = TCP_TIMEOUT_INIT; 3433 timeout += jiffies; 3434 3435 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 3436 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 3437 icsk->icsk_ack.timeout = timeout; 3438 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout); 3439 } 3440 3441 void mptcp_subflow_process_delegated(struct sock *ssk, long status) 3442 { 3443 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3444 struct sock *sk = subflow->conn; 3445 3446 if (status & BIT(MPTCP_DELEGATE_SEND)) { 3447 mptcp_data_lock(sk); 3448 if (!sock_owned_by_user(sk)) 3449 __mptcp_subflow_push_pending(sk, ssk, true); 3450 else 3451 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3452 mptcp_data_unlock(sk); 3453 } 3454 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) { 3455 mptcp_data_lock(sk); 3456 if (!sock_owned_by_user(sk)) 3457 __mptcp_sync_sndbuf(sk); 3458 else 3459 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags); 3460 mptcp_data_unlock(sk); 3461 } 3462 if (status & BIT(MPTCP_DELEGATE_ACK)) 3463 schedule_3rdack_retransmission(ssk); 3464 } 3465 3466 static int mptcp_hash(struct sock *sk) 3467 { 3468 /* should never be called, 3469 * we hash the TCP subflows not the master socket 3470 */ 3471 WARN_ON_ONCE(1); 3472 return 0; 3473 } 3474 3475 static void mptcp_unhash(struct sock *sk) 3476 { 3477 /* called from sk_common_release(), but nothing to do here */ 3478 } 3479 3480 static int mptcp_get_port(struct sock *sk, unsigned short snum) 3481 { 3482 struct mptcp_sock *msk = mptcp_sk(sk); 3483 3484 pr_debug("msk=%p, ssk=%p", msk, msk->first); 3485 if (WARN_ON_ONCE(!msk->first)) 3486 return -EINVAL; 3487 3488 return inet_csk_get_port(msk->first, snum); 3489 } 3490 3491 void mptcp_finish_connect(struct sock *ssk) 3492 { 3493 struct mptcp_subflow_context *subflow; 3494 struct mptcp_sock *msk; 3495 struct sock *sk; 3496 3497 subflow = mptcp_subflow_ctx(ssk); 3498 sk = subflow->conn; 3499 msk = mptcp_sk(sk); 3500 3501 pr_debug("msk=%p, token=%u", sk, subflow->token); 3502 3503 subflow->map_seq = subflow->iasn; 3504 subflow->map_subflow_seq = 1; 3505 3506 /* the socket is not connected yet, no msk/subflow ops can access/race 3507 * accessing the field below 3508 */ 3509 WRITE_ONCE(msk->local_key, subflow->local_key); 3510 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 3511 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 3512 WRITE_ONCE(msk->snd_una, msk->write_seq); 3513 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); 3514 3515 mptcp_pm_new_connection(msk, ssk, 0); 3516 } 3517 3518 void mptcp_sock_graft(struct sock *sk, struct socket *parent) 3519 { 3520 write_lock_bh(&sk->sk_callback_lock); 3521 rcu_assign_pointer(sk->sk_wq, &parent->wq); 3522 sk_set_socket(sk, parent); 3523 sk->sk_uid = SOCK_INODE(parent)->i_uid; 3524 write_unlock_bh(&sk->sk_callback_lock); 3525 } 3526 3527 bool mptcp_finish_join(struct sock *ssk) 3528 { 3529 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3530 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 3531 struct sock *parent = (void *)msk; 3532 bool ret = true; 3533 3534 pr_debug("msk=%p, subflow=%p", msk, subflow); 3535 3536 /* mptcp socket already closing? */ 3537 if (!mptcp_is_fully_established(parent)) { 3538 subflow->reset_reason = MPTCP_RST_EMPTCP; 3539 return false; 3540 } 3541 3542 /* active subflow, already present inside the conn_list */ 3543 if (!list_empty(&subflow->node)) { 3544 mptcp_subflow_joined(msk, ssk); 3545 mptcp_propagate_sndbuf(parent, ssk); 3546 return true; 3547 } 3548 3549 if (!mptcp_pm_allow_new_subflow(msk)) 3550 goto err_prohibited; 3551 3552 /* If we can't acquire msk socket lock here, let the release callback 3553 * handle it 3554 */ 3555 mptcp_data_lock(parent); 3556 if (!sock_owned_by_user(parent)) { 3557 ret = __mptcp_finish_join(msk, ssk); 3558 if (ret) { 3559 sock_hold(ssk); 3560 list_add_tail(&subflow->node, &msk->conn_list); 3561 } 3562 } else { 3563 sock_hold(ssk); 3564 list_add_tail(&subflow->node, &msk->join_list); 3565 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags); 3566 } 3567 mptcp_data_unlock(parent); 3568 3569 if (!ret) { 3570 err_prohibited: 3571 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3572 return false; 3573 } 3574 3575 return true; 3576 } 3577 3578 static void mptcp_shutdown(struct sock *sk, int how) 3579 { 3580 pr_debug("sk=%p, how=%d", sk, how); 3581 3582 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) 3583 __mptcp_wr_shutdown(sk); 3584 } 3585 3586 static int mptcp_forward_alloc_get(const struct sock *sk) 3587 { 3588 return READ_ONCE(sk->sk_forward_alloc) + 3589 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc); 3590 } 3591 3592 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) 3593 { 3594 const struct sock *sk = (void *)msk; 3595 u64 delta; 3596 3597 if (sk->sk_state == TCP_LISTEN) 3598 return -EINVAL; 3599 3600 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 3601 return 0; 3602 3603 delta = msk->write_seq - v; 3604 if (__mptcp_check_fallback(msk) && msk->first) { 3605 struct tcp_sock *tp = tcp_sk(msk->first); 3606 3607 /* the first subflow is disconnected after close - see 3608 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq 3609 * so ignore that status, too. 3610 */ 3611 if (!((1 << msk->first->sk_state) & 3612 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) 3613 delta += READ_ONCE(tp->write_seq) - tp->snd_una; 3614 } 3615 if (delta > INT_MAX) 3616 delta = INT_MAX; 3617 3618 return (int)delta; 3619 } 3620 3621 static int mptcp_ioctl(struct sock *sk, int cmd, int *karg) 3622 { 3623 struct mptcp_sock *msk = mptcp_sk(sk); 3624 bool slow; 3625 3626 switch (cmd) { 3627 case SIOCINQ: 3628 if (sk->sk_state == TCP_LISTEN) 3629 return -EINVAL; 3630 3631 lock_sock(sk); 3632 __mptcp_move_skbs(msk); 3633 *karg = mptcp_inq_hint(sk); 3634 release_sock(sk); 3635 break; 3636 case SIOCOUTQ: 3637 slow = lock_sock_fast(sk); 3638 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una)); 3639 unlock_sock_fast(sk, slow); 3640 break; 3641 case SIOCOUTQNSD: 3642 slow = lock_sock_fast(sk); 3643 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt); 3644 unlock_sock_fast(sk, slow); 3645 break; 3646 default: 3647 return -ENOIOCTLCMD; 3648 } 3649 3650 return 0; 3651 } 3652 3653 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 3654 struct mptcp_subflow_context *subflow) 3655 { 3656 subflow->request_mptcp = 0; 3657 __mptcp_do_fallback(msk); 3658 } 3659 3660 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 3661 { 3662 struct mptcp_subflow_context *subflow; 3663 struct mptcp_sock *msk = mptcp_sk(sk); 3664 int err = -EINVAL; 3665 struct sock *ssk; 3666 3667 ssk = __mptcp_nmpc_sk(msk); 3668 if (IS_ERR(ssk)) 3669 return PTR_ERR(ssk); 3670 3671 inet_sk_state_store(sk, TCP_SYN_SENT); 3672 subflow = mptcp_subflow_ctx(ssk); 3673 #ifdef CONFIG_TCP_MD5SIG 3674 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 3675 * TCP option space. 3676 */ 3677 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info)) 3678 mptcp_subflow_early_fallback(msk, subflow); 3679 #endif 3680 if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) { 3681 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT); 3682 mptcp_subflow_early_fallback(msk, subflow); 3683 } 3684 if (likely(!__mptcp_check_fallback(msk))) 3685 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE); 3686 3687 /* if reaching here via the fastopen/sendmsg path, the caller already 3688 * acquired the subflow socket lock, too. 3689 */ 3690 if (!msk->fastopening) 3691 lock_sock(ssk); 3692 3693 /* the following mirrors closely a very small chunk of code from 3694 * __inet_stream_connect() 3695 */ 3696 if (ssk->sk_state != TCP_CLOSE) 3697 goto out; 3698 3699 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) { 3700 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len); 3701 if (err) 3702 goto out; 3703 } 3704 3705 err = ssk->sk_prot->connect(ssk, uaddr, addr_len); 3706 if (err < 0) 3707 goto out; 3708 3709 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk)); 3710 3711 out: 3712 if (!msk->fastopening) 3713 release_sock(ssk); 3714 3715 /* on successful connect, the msk state will be moved to established by 3716 * subflow_finish_connect() 3717 */ 3718 if (unlikely(err)) { 3719 /* avoid leaving a dangling token in an unconnected socket */ 3720 mptcp_token_destroy(msk); 3721 inet_sk_state_store(sk, TCP_CLOSE); 3722 return err; 3723 } 3724 3725 mptcp_copy_inaddrs(sk, ssk); 3726 return 0; 3727 } 3728 3729 static struct proto mptcp_prot = { 3730 .name = "MPTCP", 3731 .owner = THIS_MODULE, 3732 .init = mptcp_init_sock, 3733 .connect = mptcp_connect, 3734 .disconnect = mptcp_disconnect, 3735 .close = mptcp_close, 3736 .accept = mptcp_accept, 3737 .setsockopt = mptcp_setsockopt, 3738 .getsockopt = mptcp_getsockopt, 3739 .shutdown = mptcp_shutdown, 3740 .destroy = mptcp_destroy, 3741 .sendmsg = mptcp_sendmsg, 3742 .ioctl = mptcp_ioctl, 3743 .recvmsg = mptcp_recvmsg, 3744 .release_cb = mptcp_release_cb, 3745 .hash = mptcp_hash, 3746 .unhash = mptcp_unhash, 3747 .get_port = mptcp_get_port, 3748 .forward_alloc_get = mptcp_forward_alloc_get, 3749 .sockets_allocated = &mptcp_sockets_allocated, 3750 3751 .memory_allocated = &tcp_memory_allocated, 3752 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3753 3754 .memory_pressure = &tcp_memory_pressure, 3755 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3756 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3757 .sysctl_mem = sysctl_tcp_mem, 3758 .obj_size = sizeof(struct mptcp_sock), 3759 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3760 .no_autobind = true, 3761 }; 3762 3763 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 3764 { 3765 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3766 struct sock *ssk, *sk = sock->sk; 3767 int err = -EINVAL; 3768 3769 lock_sock(sk); 3770 ssk = __mptcp_nmpc_sk(msk); 3771 if (IS_ERR(ssk)) { 3772 err = PTR_ERR(ssk); 3773 goto unlock; 3774 } 3775 3776 if (sk->sk_family == AF_INET) 3777 err = inet_bind_sk(ssk, uaddr, addr_len); 3778 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3779 else if (sk->sk_family == AF_INET6) 3780 err = inet6_bind_sk(ssk, uaddr, addr_len); 3781 #endif 3782 if (!err) 3783 mptcp_copy_inaddrs(sk, ssk); 3784 3785 unlock: 3786 release_sock(sk); 3787 return err; 3788 } 3789 3790 static int mptcp_listen(struct socket *sock, int backlog) 3791 { 3792 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3793 struct sock *sk = sock->sk; 3794 struct sock *ssk; 3795 int err; 3796 3797 pr_debug("msk=%p", msk); 3798 3799 lock_sock(sk); 3800 3801 err = -EINVAL; 3802 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM) 3803 goto unlock; 3804 3805 ssk = __mptcp_nmpc_sk(msk); 3806 if (IS_ERR(ssk)) { 3807 err = PTR_ERR(ssk); 3808 goto unlock; 3809 } 3810 3811 inet_sk_state_store(sk, TCP_LISTEN); 3812 sock_set_flag(sk, SOCK_RCU_FREE); 3813 3814 lock_sock(ssk); 3815 err = __inet_listen_sk(ssk, backlog); 3816 release_sock(ssk); 3817 inet_sk_state_store(sk, inet_sk_state_load(ssk)); 3818 3819 if (!err) { 3820 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 3821 mptcp_copy_inaddrs(sk, ssk); 3822 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED); 3823 } 3824 3825 unlock: 3826 release_sock(sk); 3827 return err; 3828 } 3829 3830 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 3831 int flags, bool kern) 3832 { 3833 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3834 struct sock *ssk, *newsk; 3835 int err; 3836 3837 pr_debug("msk=%p", msk); 3838 3839 /* Buggy applications can call accept on socket states other then LISTEN 3840 * but no need to allocate the first subflow just to error out. 3841 */ 3842 ssk = READ_ONCE(msk->first); 3843 if (!ssk) 3844 return -EINVAL; 3845 3846 newsk = mptcp_accept(ssk, flags, &err, kern); 3847 if (!newsk) 3848 return err; 3849 3850 lock_sock(newsk); 3851 3852 __inet_accept(sock, newsock, newsk); 3853 if (!mptcp_is_tcpsk(newsock->sk)) { 3854 struct mptcp_sock *msk = mptcp_sk(newsk); 3855 struct mptcp_subflow_context *subflow; 3856 3857 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); 3858 msk->in_accept_queue = 0; 3859 3860 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 3861 * This is needed so NOSPACE flag can be set from tcp stack. 3862 */ 3863 mptcp_for_each_subflow(msk, subflow) { 3864 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3865 3866 if (!ssk->sk_socket) 3867 mptcp_sock_graft(ssk, newsock); 3868 } 3869 3870 /* Do late cleanup for the first subflow as necessary. Also 3871 * deal with bad peers not doing a complete shutdown. 3872 */ 3873 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) { 3874 __mptcp_close_ssk(newsk, msk->first, 3875 mptcp_subflow_ctx(msk->first), 0); 3876 if (unlikely(list_is_singular(&msk->conn_list))) 3877 inet_sk_state_store(newsk, TCP_CLOSE); 3878 } 3879 } 3880 release_sock(newsk); 3881 3882 return 0; 3883 } 3884 3885 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) 3886 { 3887 struct sock *sk = (struct sock *)msk; 3888 3889 if (sk_stream_is_writeable(sk)) 3890 return EPOLLOUT | EPOLLWRNORM; 3891 3892 mptcp_set_nospace(sk); 3893 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 3894 if (sk_stream_is_writeable(sk)) 3895 return EPOLLOUT | EPOLLWRNORM; 3896 3897 return 0; 3898 } 3899 3900 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 3901 struct poll_table_struct *wait) 3902 { 3903 struct sock *sk = sock->sk; 3904 struct mptcp_sock *msk; 3905 __poll_t mask = 0; 3906 u8 shutdown; 3907 int state; 3908 3909 msk = mptcp_sk(sk); 3910 sock_poll_wait(file, sock, wait); 3911 3912 state = inet_sk_state_load(sk); 3913 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); 3914 if (state == TCP_LISTEN) { 3915 struct sock *ssk = READ_ONCE(msk->first); 3916 3917 if (WARN_ON_ONCE(!ssk)) 3918 return 0; 3919 3920 return inet_csk_listen_poll(ssk); 3921 } 3922 3923 shutdown = READ_ONCE(sk->sk_shutdown); 3924 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) 3925 mask |= EPOLLHUP; 3926 if (shutdown & RCV_SHUTDOWN) 3927 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 3928 3929 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 3930 mask |= mptcp_check_readable(msk); 3931 if (shutdown & SEND_SHUTDOWN) 3932 mask |= EPOLLOUT | EPOLLWRNORM; 3933 else 3934 mask |= mptcp_check_writeable(msk); 3935 } else if (state == TCP_SYN_SENT && 3936 inet_test_bit(DEFER_CONNECT, sk)) { 3937 /* cf tcp_poll() note about TFO */ 3938 mask |= EPOLLOUT | EPOLLWRNORM; 3939 } 3940 3941 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */ 3942 smp_rmb(); 3943 if (READ_ONCE(sk->sk_err)) 3944 mask |= EPOLLERR; 3945 3946 return mask; 3947 } 3948 3949 static const struct proto_ops mptcp_stream_ops = { 3950 .family = PF_INET, 3951 .owner = THIS_MODULE, 3952 .release = inet_release, 3953 .bind = mptcp_bind, 3954 .connect = inet_stream_connect, 3955 .socketpair = sock_no_socketpair, 3956 .accept = mptcp_stream_accept, 3957 .getname = inet_getname, 3958 .poll = mptcp_poll, 3959 .ioctl = inet_ioctl, 3960 .gettstamp = sock_gettstamp, 3961 .listen = mptcp_listen, 3962 .shutdown = inet_shutdown, 3963 .setsockopt = sock_common_setsockopt, 3964 .getsockopt = sock_common_getsockopt, 3965 .sendmsg = inet_sendmsg, 3966 .recvmsg = inet_recvmsg, 3967 .mmap = sock_no_mmap, 3968 }; 3969 3970 static struct inet_protosw mptcp_protosw = { 3971 .type = SOCK_STREAM, 3972 .protocol = IPPROTO_MPTCP, 3973 .prot = &mptcp_prot, 3974 .ops = &mptcp_stream_ops, 3975 .flags = INET_PROTOSW_ICSK, 3976 }; 3977 3978 static int mptcp_napi_poll(struct napi_struct *napi, int budget) 3979 { 3980 struct mptcp_delegated_action *delegated; 3981 struct mptcp_subflow_context *subflow; 3982 int work_done = 0; 3983 3984 delegated = container_of(napi, struct mptcp_delegated_action, napi); 3985 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { 3986 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3987 3988 bh_lock_sock_nested(ssk); 3989 if (!sock_owned_by_user(ssk)) { 3990 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0)); 3991 } else { 3992 /* tcp_release_cb_override already processed 3993 * the action or will do at next release_sock(). 3994 * In both case must dequeue the subflow here - on the same 3995 * CPU that scheduled it. 3996 */ 3997 smp_wmb(); 3998 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status); 3999 } 4000 bh_unlock_sock(ssk); 4001 sock_put(ssk); 4002 4003 if (++work_done == budget) 4004 return budget; 4005 } 4006 4007 /* always provide a 0 'work_done' argument, so that napi_complete_done 4008 * will not try accessing the NULL napi->dev ptr 4009 */ 4010 napi_complete_done(napi, 0); 4011 return work_done; 4012 } 4013 4014 void __init mptcp_proto_init(void) 4015 { 4016 struct mptcp_delegated_action *delegated; 4017 int cpu; 4018 4019 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 4020 4021 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 4022 panic("Failed to allocate MPTCP pcpu counter\n"); 4023 4024 init_dummy_netdev(&mptcp_napi_dev); 4025 for_each_possible_cpu(cpu) { 4026 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); 4027 INIT_LIST_HEAD(&delegated->head); 4028 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi, 4029 mptcp_napi_poll); 4030 napi_enable(&delegated->napi); 4031 } 4032 4033 mptcp_subflow_init(); 4034 mptcp_pm_init(); 4035 mptcp_sched_init(); 4036 mptcp_token_init(); 4037 4038 if (proto_register(&mptcp_prot, 1) != 0) 4039 panic("Failed to register MPTCP proto.\n"); 4040 4041 inet_register_protosw(&mptcp_protosw); 4042 4043 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 4044 } 4045 4046 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 4047 static const struct proto_ops mptcp_v6_stream_ops = { 4048 .family = PF_INET6, 4049 .owner = THIS_MODULE, 4050 .release = inet6_release, 4051 .bind = mptcp_bind, 4052 .connect = inet_stream_connect, 4053 .socketpair = sock_no_socketpair, 4054 .accept = mptcp_stream_accept, 4055 .getname = inet6_getname, 4056 .poll = mptcp_poll, 4057 .ioctl = inet6_ioctl, 4058 .gettstamp = sock_gettstamp, 4059 .listen = mptcp_listen, 4060 .shutdown = inet_shutdown, 4061 .setsockopt = sock_common_setsockopt, 4062 .getsockopt = sock_common_getsockopt, 4063 .sendmsg = inet6_sendmsg, 4064 .recvmsg = inet6_recvmsg, 4065 .mmap = sock_no_mmap, 4066 #ifdef CONFIG_COMPAT 4067 .compat_ioctl = inet6_compat_ioctl, 4068 #endif 4069 }; 4070 4071 static struct proto mptcp_v6_prot; 4072 4073 static struct inet_protosw mptcp_v6_protosw = { 4074 .type = SOCK_STREAM, 4075 .protocol = IPPROTO_MPTCP, 4076 .prot = &mptcp_v6_prot, 4077 .ops = &mptcp_v6_stream_ops, 4078 .flags = INET_PROTOSW_ICSK, 4079 }; 4080 4081 int __init mptcp_proto_v6_init(void) 4082 { 4083 int err; 4084 4085 mptcp_v6_prot = mptcp_prot; 4086 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 4087 mptcp_v6_prot.slab = NULL; 4088 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 4089 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np); 4090 4091 err = proto_register(&mptcp_v6_prot, 1); 4092 if (err) 4093 return err; 4094 4095 err = inet6_register_protosw(&mptcp_v6_protosw); 4096 if (err) 4097 proto_unregister(&mptcp_v6_prot); 4098 4099 return err; 4100 } 4101 #endif 4102