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 } 125 126 return msk->first; 127 } 128 129 static void mptcp_drop(struct sock *sk, struct sk_buff *skb) 130 { 131 sk_drops_add(sk, skb); 132 __kfree_skb(skb); 133 } 134 135 static void mptcp_rmem_fwd_alloc_add(struct sock *sk, int size) 136 { 137 WRITE_ONCE(mptcp_sk(sk)->rmem_fwd_alloc, 138 mptcp_sk(sk)->rmem_fwd_alloc + size); 139 } 140 141 static void mptcp_rmem_charge(struct sock *sk, int size) 142 { 143 mptcp_rmem_fwd_alloc_add(sk, -size); 144 } 145 146 static bool mptcp_try_coalesce(struct sock *sk, struct sk_buff *to, 147 struct sk_buff *from) 148 { 149 bool fragstolen; 150 int delta; 151 152 if (MPTCP_SKB_CB(from)->offset || 153 !skb_try_coalesce(to, from, &fragstolen, &delta)) 154 return false; 155 156 pr_debug("colesced seq %llx into %llx new len %d new end seq %llx", 157 MPTCP_SKB_CB(from)->map_seq, MPTCP_SKB_CB(to)->map_seq, 158 to->len, MPTCP_SKB_CB(from)->end_seq); 159 MPTCP_SKB_CB(to)->end_seq = MPTCP_SKB_CB(from)->end_seq; 160 161 /* note the fwd memory can reach a negative value after accounting 162 * for the delta, but the later skb free will restore a non 163 * negative one 164 */ 165 atomic_add(delta, &sk->sk_rmem_alloc); 166 mptcp_rmem_charge(sk, delta); 167 kfree_skb_partial(from, fragstolen); 168 169 return true; 170 } 171 172 static bool mptcp_ooo_try_coalesce(struct mptcp_sock *msk, struct sk_buff *to, 173 struct sk_buff *from) 174 { 175 if (MPTCP_SKB_CB(from)->map_seq != MPTCP_SKB_CB(to)->end_seq) 176 return false; 177 178 return mptcp_try_coalesce((struct sock *)msk, to, from); 179 } 180 181 static void __mptcp_rmem_reclaim(struct sock *sk, int amount) 182 { 183 amount >>= PAGE_SHIFT; 184 mptcp_rmem_charge(sk, amount << PAGE_SHIFT); 185 __sk_mem_reduce_allocated(sk, amount); 186 } 187 188 static void mptcp_rmem_uncharge(struct sock *sk, int size) 189 { 190 struct mptcp_sock *msk = mptcp_sk(sk); 191 int reclaimable; 192 193 mptcp_rmem_fwd_alloc_add(sk, size); 194 reclaimable = msk->rmem_fwd_alloc - sk_unused_reserved_mem(sk); 195 196 /* see sk_mem_uncharge() for the rationale behind the following schema */ 197 if (unlikely(reclaimable >= PAGE_SIZE)) 198 __mptcp_rmem_reclaim(sk, reclaimable); 199 } 200 201 static void mptcp_rfree(struct sk_buff *skb) 202 { 203 unsigned int len = skb->truesize; 204 struct sock *sk = skb->sk; 205 206 atomic_sub(len, &sk->sk_rmem_alloc); 207 mptcp_rmem_uncharge(sk, len); 208 } 209 210 void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk) 211 { 212 skb_orphan(skb); 213 skb->sk = sk; 214 skb->destructor = mptcp_rfree; 215 atomic_add(skb->truesize, &sk->sk_rmem_alloc); 216 mptcp_rmem_charge(sk, skb->truesize); 217 } 218 219 /* "inspired" by tcp_data_queue_ofo(), main differences: 220 * - use mptcp seqs 221 * - don't cope with sacks 222 */ 223 static void mptcp_data_queue_ofo(struct mptcp_sock *msk, struct sk_buff *skb) 224 { 225 struct sock *sk = (struct sock *)msk; 226 struct rb_node **p, *parent; 227 u64 seq, end_seq, max_seq; 228 struct sk_buff *skb1; 229 230 seq = MPTCP_SKB_CB(skb)->map_seq; 231 end_seq = MPTCP_SKB_CB(skb)->end_seq; 232 max_seq = atomic64_read(&msk->rcv_wnd_sent); 233 234 pr_debug("msk=%p seq=%llx limit=%llx empty=%d", msk, seq, max_seq, 235 RB_EMPTY_ROOT(&msk->out_of_order_queue)); 236 if (after64(end_seq, max_seq)) { 237 /* out of window */ 238 mptcp_drop(sk, skb); 239 pr_debug("oow by %lld, rcv_wnd_sent %llu\n", 240 (unsigned long long)end_seq - (unsigned long)max_seq, 241 (unsigned long long)atomic64_read(&msk->rcv_wnd_sent)); 242 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_NODSSWINDOW); 243 return; 244 } 245 246 p = &msk->out_of_order_queue.rb_node; 247 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUE); 248 if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) { 249 rb_link_node(&skb->rbnode, NULL, p); 250 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 251 msk->ooo_last_skb = skb; 252 goto end; 253 } 254 255 /* with 2 subflows, adding at end of ooo queue is quite likely 256 * Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup. 257 */ 258 if (mptcp_ooo_try_coalesce(msk, msk->ooo_last_skb, skb)) { 259 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 260 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 261 return; 262 } 263 264 /* Can avoid an rbtree lookup if we are adding skb after ooo_last_skb */ 265 if (!before64(seq, MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq)) { 266 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOQUEUETAIL); 267 parent = &msk->ooo_last_skb->rbnode; 268 p = &parent->rb_right; 269 goto insert; 270 } 271 272 /* Find place to insert this segment. Handle overlaps on the way. */ 273 parent = NULL; 274 while (*p) { 275 parent = *p; 276 skb1 = rb_to_skb(parent); 277 if (before64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 278 p = &parent->rb_left; 279 continue; 280 } 281 if (before64(seq, MPTCP_SKB_CB(skb1)->end_seq)) { 282 if (!after64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) { 283 /* All the bits are present. Drop. */ 284 mptcp_drop(sk, skb); 285 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 286 return; 287 } 288 if (after64(seq, MPTCP_SKB_CB(skb1)->map_seq)) { 289 /* partial overlap: 290 * | skb | 291 * | skb1 | 292 * continue traversing 293 */ 294 } else { 295 /* skb's seq == skb1's seq and skb covers skb1. 296 * Replace skb1 with skb. 297 */ 298 rb_replace_node(&skb1->rbnode, &skb->rbnode, 299 &msk->out_of_order_queue); 300 mptcp_drop(sk, skb1); 301 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 302 goto merge_right; 303 } 304 } else if (mptcp_ooo_try_coalesce(msk, skb1, skb)) { 305 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOMERGE); 306 return; 307 } 308 p = &parent->rb_right; 309 } 310 311 insert: 312 /* Insert segment into RB tree. */ 313 rb_link_node(&skb->rbnode, parent, p); 314 rb_insert_color(&skb->rbnode, &msk->out_of_order_queue); 315 316 merge_right: 317 /* Remove other segments covered by skb. */ 318 while ((skb1 = skb_rb_next(skb)) != NULL) { 319 if (before64(end_seq, MPTCP_SKB_CB(skb1)->end_seq)) 320 break; 321 rb_erase(&skb1->rbnode, &msk->out_of_order_queue); 322 mptcp_drop(sk, skb1); 323 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 324 } 325 /* If there is no skb after us, we are the last_skb ! */ 326 if (!skb1) 327 msk->ooo_last_skb = skb; 328 329 end: 330 skb_condense(skb); 331 mptcp_set_owner_r(skb, sk); 332 } 333 334 static bool mptcp_rmem_schedule(struct sock *sk, struct sock *ssk, int size) 335 { 336 struct mptcp_sock *msk = mptcp_sk(sk); 337 int amt, amount; 338 339 if (size <= msk->rmem_fwd_alloc) 340 return true; 341 342 size -= msk->rmem_fwd_alloc; 343 amt = sk_mem_pages(size); 344 amount = amt << PAGE_SHIFT; 345 if (!__sk_mem_raise_allocated(sk, size, amt, SK_MEM_RECV)) 346 return false; 347 348 mptcp_rmem_fwd_alloc_add(sk, amount); 349 return true; 350 } 351 352 static bool __mptcp_move_skb(struct mptcp_sock *msk, struct sock *ssk, 353 struct sk_buff *skb, unsigned int offset, 354 size_t copy_len) 355 { 356 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 357 struct sock *sk = (struct sock *)msk; 358 struct sk_buff *tail; 359 bool has_rxtstamp; 360 361 __skb_unlink(skb, &ssk->sk_receive_queue); 362 363 skb_ext_reset(skb); 364 skb_orphan(skb); 365 366 /* try to fetch required memory from subflow */ 367 if (!mptcp_rmem_schedule(sk, ssk, skb->truesize)) 368 goto drop; 369 370 has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp; 371 372 /* the skb map_seq accounts for the skb offset: 373 * mptcp_subflow_get_mapped_dsn() is based on the current tp->copied_seq 374 * value 375 */ 376 MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow); 377 MPTCP_SKB_CB(skb)->end_seq = MPTCP_SKB_CB(skb)->map_seq + copy_len; 378 MPTCP_SKB_CB(skb)->offset = offset; 379 MPTCP_SKB_CB(skb)->has_rxtstamp = has_rxtstamp; 380 381 if (MPTCP_SKB_CB(skb)->map_seq == msk->ack_seq) { 382 /* in sequence */ 383 msk->bytes_received += copy_len; 384 WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); 385 tail = skb_peek_tail(&sk->sk_receive_queue); 386 if (tail && mptcp_try_coalesce(sk, tail, skb)) 387 return true; 388 389 mptcp_set_owner_r(skb, sk); 390 __skb_queue_tail(&sk->sk_receive_queue, skb); 391 return true; 392 } else if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) { 393 mptcp_data_queue_ofo(msk, skb); 394 return false; 395 } 396 397 /* old data, keep it simple and drop the whole pkt, sender 398 * will retransmit as needed, if needed. 399 */ 400 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 401 drop: 402 mptcp_drop(sk, skb); 403 return false; 404 } 405 406 static void mptcp_stop_rtx_timer(struct sock *sk) 407 { 408 struct inet_connection_sock *icsk = inet_csk(sk); 409 410 sk_stop_timer(sk, &icsk->icsk_retransmit_timer); 411 mptcp_sk(sk)->timer_ival = 0; 412 } 413 414 static void mptcp_close_wake_up(struct sock *sk) 415 { 416 if (sock_flag(sk, SOCK_DEAD)) 417 return; 418 419 sk->sk_state_change(sk); 420 if (sk->sk_shutdown == SHUTDOWN_MASK || 421 sk->sk_state == TCP_CLOSE) 422 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_HUP); 423 else 424 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); 425 } 426 427 static bool mptcp_pending_data_fin_ack(struct sock *sk) 428 { 429 struct mptcp_sock *msk = mptcp_sk(sk); 430 431 return ((1 << sk->sk_state) & 432 (TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK)) && 433 msk->write_seq == READ_ONCE(msk->snd_una); 434 } 435 436 static void mptcp_check_data_fin_ack(struct sock *sk) 437 { 438 struct mptcp_sock *msk = mptcp_sk(sk); 439 440 /* Look for an acknowledged DATA_FIN */ 441 if (mptcp_pending_data_fin_ack(sk)) { 442 WRITE_ONCE(msk->snd_data_fin_enable, 0); 443 444 switch (sk->sk_state) { 445 case TCP_FIN_WAIT1: 446 inet_sk_state_store(sk, TCP_FIN_WAIT2); 447 break; 448 case TCP_CLOSING: 449 case TCP_LAST_ACK: 450 inet_sk_state_store(sk, TCP_CLOSE); 451 break; 452 } 453 454 mptcp_close_wake_up(sk); 455 } 456 } 457 458 static bool mptcp_pending_data_fin(struct sock *sk, u64 *seq) 459 { 460 struct mptcp_sock *msk = mptcp_sk(sk); 461 462 if (READ_ONCE(msk->rcv_data_fin) && 463 ((1 << sk->sk_state) & 464 (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2))) { 465 u64 rcv_data_fin_seq = READ_ONCE(msk->rcv_data_fin_seq); 466 467 if (msk->ack_seq == rcv_data_fin_seq) { 468 if (seq) 469 *seq = rcv_data_fin_seq; 470 471 return true; 472 } 473 } 474 475 return false; 476 } 477 478 static void mptcp_set_datafin_timeout(struct sock *sk) 479 { 480 struct inet_connection_sock *icsk = inet_csk(sk); 481 u32 retransmits; 482 483 retransmits = min_t(u32, icsk->icsk_retransmits, 484 ilog2(TCP_RTO_MAX / TCP_RTO_MIN)); 485 486 mptcp_sk(sk)->timer_ival = TCP_RTO_MIN << retransmits; 487 } 488 489 static void __mptcp_set_timeout(struct sock *sk, long tout) 490 { 491 mptcp_sk(sk)->timer_ival = tout > 0 ? tout : TCP_RTO_MIN; 492 } 493 494 static long mptcp_timeout_from_subflow(const struct mptcp_subflow_context *subflow) 495 { 496 const struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 497 498 return inet_csk(ssk)->icsk_pending && !subflow->stale_count ? 499 inet_csk(ssk)->icsk_timeout - jiffies : 0; 500 } 501 502 static void mptcp_set_timeout(struct sock *sk) 503 { 504 struct mptcp_subflow_context *subflow; 505 long tout = 0; 506 507 mptcp_for_each_subflow(mptcp_sk(sk), subflow) 508 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 509 __mptcp_set_timeout(sk, tout); 510 } 511 512 static inline bool tcp_can_send_ack(const struct sock *ssk) 513 { 514 return !((1 << inet_sk_state_load(ssk)) & 515 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); 516 } 517 518 void __mptcp_subflow_send_ack(struct sock *ssk) 519 { 520 if (tcp_can_send_ack(ssk)) 521 tcp_send_ack(ssk); 522 } 523 524 static void mptcp_subflow_send_ack(struct sock *ssk) 525 { 526 bool slow; 527 528 slow = lock_sock_fast(ssk); 529 __mptcp_subflow_send_ack(ssk); 530 unlock_sock_fast(ssk, slow); 531 } 532 533 static void mptcp_send_ack(struct mptcp_sock *msk) 534 { 535 struct mptcp_subflow_context *subflow; 536 537 mptcp_for_each_subflow(msk, subflow) 538 mptcp_subflow_send_ack(mptcp_subflow_tcp_sock(subflow)); 539 } 540 541 static void mptcp_subflow_cleanup_rbuf(struct sock *ssk) 542 { 543 bool slow; 544 545 slow = lock_sock_fast(ssk); 546 if (tcp_can_send_ack(ssk)) 547 tcp_cleanup_rbuf(ssk, 1); 548 unlock_sock_fast(ssk, slow); 549 } 550 551 static bool mptcp_subflow_could_cleanup(const struct sock *ssk, bool rx_empty) 552 { 553 const struct inet_connection_sock *icsk = inet_csk(ssk); 554 u8 ack_pending = READ_ONCE(icsk->icsk_ack.pending); 555 const struct tcp_sock *tp = tcp_sk(ssk); 556 557 return (ack_pending & ICSK_ACK_SCHED) && 558 ((READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->rcv_wup) > 559 READ_ONCE(icsk->icsk_ack.rcv_mss)) || 560 (rx_empty && ack_pending & 561 (ICSK_ACK_PUSHED2 | ICSK_ACK_PUSHED))); 562 } 563 564 static void mptcp_cleanup_rbuf(struct mptcp_sock *msk) 565 { 566 int old_space = READ_ONCE(msk->old_wspace); 567 struct mptcp_subflow_context *subflow; 568 struct sock *sk = (struct sock *)msk; 569 int space = __mptcp_space(sk); 570 bool cleanup, rx_empty; 571 572 cleanup = (space > 0) && (space >= (old_space << 1)); 573 rx_empty = !__mptcp_rmem(sk); 574 575 mptcp_for_each_subflow(msk, subflow) { 576 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 577 578 if (cleanup || mptcp_subflow_could_cleanup(ssk, rx_empty)) 579 mptcp_subflow_cleanup_rbuf(ssk); 580 } 581 } 582 583 static bool mptcp_check_data_fin(struct sock *sk) 584 { 585 struct mptcp_sock *msk = mptcp_sk(sk); 586 u64 rcv_data_fin_seq; 587 bool ret = false; 588 589 /* Need to ack a DATA_FIN received from a peer while this side 590 * of the connection is in ESTABLISHED, FIN_WAIT1, or FIN_WAIT2. 591 * msk->rcv_data_fin was set when parsing the incoming options 592 * at the subflow level and the msk lock was not held, so this 593 * is the first opportunity to act on the DATA_FIN and change 594 * the msk state. 595 * 596 * If we are caught up to the sequence number of the incoming 597 * DATA_FIN, send the DATA_ACK now and do state transition. If 598 * not caught up, do nothing and let the recv code send DATA_ACK 599 * when catching up. 600 */ 601 602 if (mptcp_pending_data_fin(sk, &rcv_data_fin_seq)) { 603 WRITE_ONCE(msk->ack_seq, msk->ack_seq + 1); 604 WRITE_ONCE(msk->rcv_data_fin, 0); 605 606 WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN); 607 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 608 609 switch (sk->sk_state) { 610 case TCP_ESTABLISHED: 611 inet_sk_state_store(sk, TCP_CLOSE_WAIT); 612 break; 613 case TCP_FIN_WAIT1: 614 inet_sk_state_store(sk, TCP_CLOSING); 615 break; 616 case TCP_FIN_WAIT2: 617 inet_sk_state_store(sk, TCP_CLOSE); 618 break; 619 default: 620 /* Other states not expected */ 621 WARN_ON_ONCE(1); 622 break; 623 } 624 625 ret = true; 626 if (!__mptcp_check_fallback(msk)) 627 mptcp_send_ack(msk); 628 mptcp_close_wake_up(sk); 629 } 630 return ret; 631 } 632 633 static bool __mptcp_move_skbs_from_subflow(struct mptcp_sock *msk, 634 struct sock *ssk, 635 unsigned int *bytes) 636 { 637 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 638 struct sock *sk = (struct sock *)msk; 639 unsigned int moved = 0; 640 bool more_data_avail; 641 struct tcp_sock *tp; 642 bool done = false; 643 int sk_rbuf; 644 645 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 646 647 if (!(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 648 int ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 649 650 if (unlikely(ssk_rbuf > sk_rbuf)) { 651 WRITE_ONCE(sk->sk_rcvbuf, ssk_rbuf); 652 sk_rbuf = ssk_rbuf; 653 } 654 } 655 656 pr_debug("msk=%p ssk=%p", msk, ssk); 657 tp = tcp_sk(ssk); 658 do { 659 u32 map_remaining, offset; 660 u32 seq = tp->copied_seq; 661 struct sk_buff *skb; 662 bool fin; 663 664 /* try to move as much data as available */ 665 map_remaining = subflow->map_data_len - 666 mptcp_subflow_get_map_offset(subflow); 667 668 skb = skb_peek(&ssk->sk_receive_queue); 669 if (!skb) { 670 /* With racing move_skbs_to_msk() and __mptcp_move_skbs(), 671 * a different CPU can have already processed the pending 672 * data, stop here or we can enter an infinite loop 673 */ 674 if (!moved) 675 done = true; 676 break; 677 } 678 679 if (__mptcp_check_fallback(msk)) { 680 /* Under fallback skbs have no MPTCP extension and TCP could 681 * collapse them between the dummy map creation and the 682 * current dequeue. Be sure to adjust the map size. 683 */ 684 map_remaining = skb->len; 685 subflow->map_data_len = skb->len; 686 } 687 688 offset = seq - TCP_SKB_CB(skb)->seq; 689 fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; 690 if (fin) { 691 done = true; 692 seq++; 693 } 694 695 if (offset < skb->len) { 696 size_t len = skb->len - offset; 697 698 if (tp->urg_data) 699 done = true; 700 701 if (__mptcp_move_skb(msk, ssk, skb, offset, len)) 702 moved += len; 703 seq += len; 704 705 if (WARN_ON_ONCE(map_remaining < len)) 706 break; 707 } else { 708 WARN_ON_ONCE(!fin); 709 sk_eat_skb(ssk, skb); 710 done = true; 711 } 712 713 WRITE_ONCE(tp->copied_seq, seq); 714 more_data_avail = mptcp_subflow_data_available(ssk); 715 716 if (atomic_read(&sk->sk_rmem_alloc) > sk_rbuf) { 717 done = true; 718 break; 719 } 720 } while (more_data_avail); 721 722 *bytes += moved; 723 return done; 724 } 725 726 static bool __mptcp_ofo_queue(struct mptcp_sock *msk) 727 { 728 struct sock *sk = (struct sock *)msk; 729 struct sk_buff *skb, *tail; 730 bool moved = false; 731 struct rb_node *p; 732 u64 end_seq; 733 734 p = rb_first(&msk->out_of_order_queue); 735 pr_debug("msk=%p empty=%d", msk, RB_EMPTY_ROOT(&msk->out_of_order_queue)); 736 while (p) { 737 skb = rb_to_skb(p); 738 if (after64(MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq)) 739 break; 740 741 p = rb_next(p); 742 rb_erase(&skb->rbnode, &msk->out_of_order_queue); 743 744 if (unlikely(!after64(MPTCP_SKB_CB(skb)->end_seq, 745 msk->ack_seq))) { 746 mptcp_drop(sk, skb); 747 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); 748 continue; 749 } 750 751 end_seq = MPTCP_SKB_CB(skb)->end_seq; 752 tail = skb_peek_tail(&sk->sk_receive_queue); 753 if (!tail || !mptcp_ooo_try_coalesce(msk, tail, skb)) { 754 int delta = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 755 756 /* skip overlapping data, if any */ 757 pr_debug("uncoalesced seq=%llx ack seq=%llx delta=%d", 758 MPTCP_SKB_CB(skb)->map_seq, msk->ack_seq, 759 delta); 760 MPTCP_SKB_CB(skb)->offset += delta; 761 MPTCP_SKB_CB(skb)->map_seq += delta; 762 __skb_queue_tail(&sk->sk_receive_queue, skb); 763 } 764 msk->bytes_received += end_seq - msk->ack_seq; 765 msk->ack_seq = end_seq; 766 moved = true; 767 } 768 return moved; 769 } 770 771 static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk) 772 { 773 int err = sock_error(ssk); 774 int ssk_state; 775 776 if (!err) 777 return false; 778 779 /* only propagate errors on fallen-back sockets or 780 * on MPC connect 781 */ 782 if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk))) 783 return false; 784 785 /* We need to propagate only transition to CLOSE state. 786 * Orphaned socket will see such state change via 787 * subflow_sched_work_if_closed() and that path will properly 788 * destroy the msk as needed. 789 */ 790 ssk_state = inet_sk_state_load(ssk); 791 if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD)) 792 inet_sk_state_store(sk, ssk_state); 793 WRITE_ONCE(sk->sk_err, -err); 794 795 /* This barrier is coupled with smp_rmb() in mptcp_poll() */ 796 smp_wmb(); 797 sk_error_report(sk); 798 return true; 799 } 800 801 void __mptcp_error_report(struct sock *sk) 802 { 803 struct mptcp_subflow_context *subflow; 804 struct mptcp_sock *msk = mptcp_sk(sk); 805 806 mptcp_for_each_subflow(msk, subflow) 807 if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow))) 808 break; 809 } 810 811 /* In most cases we will be able to lock the mptcp socket. If its already 812 * owned, we need to defer to the work queue to avoid ABBA deadlock. 813 */ 814 static bool move_skbs_to_msk(struct mptcp_sock *msk, struct sock *ssk) 815 { 816 struct sock *sk = (struct sock *)msk; 817 unsigned int moved = 0; 818 819 __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 820 __mptcp_ofo_queue(msk); 821 if (unlikely(ssk->sk_err)) { 822 if (!sock_owned_by_user(sk)) 823 __mptcp_error_report(sk); 824 else 825 __set_bit(MPTCP_ERROR_REPORT, &msk->cb_flags); 826 } 827 828 /* If the moves have caught up with the DATA_FIN sequence number 829 * it's time to ack the DATA_FIN and change socket state, but 830 * this is not a good place to change state. Let the workqueue 831 * do it. 832 */ 833 if (mptcp_pending_data_fin(sk, NULL)) 834 mptcp_schedule_work(sk); 835 return moved > 0; 836 } 837 838 void mptcp_data_ready(struct sock *sk, struct sock *ssk) 839 { 840 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 841 struct mptcp_sock *msk = mptcp_sk(sk); 842 int sk_rbuf, ssk_rbuf; 843 844 /* The peer can send data while we are shutting down this 845 * subflow at msk destruction time, but we must avoid enqueuing 846 * more data to the msk receive queue 847 */ 848 if (unlikely(subflow->disposable)) 849 return; 850 851 ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); 852 sk_rbuf = READ_ONCE(sk->sk_rcvbuf); 853 if (unlikely(ssk_rbuf > sk_rbuf)) 854 sk_rbuf = ssk_rbuf; 855 856 /* over limit? can't append more skbs to msk, Also, no need to wake-up*/ 857 if (__mptcp_rmem(sk) > sk_rbuf) { 858 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RCVPRUNED); 859 return; 860 } 861 862 /* Wake-up the reader only for in-sequence data */ 863 mptcp_data_lock(sk); 864 if (move_skbs_to_msk(msk, ssk) && mptcp_epollin_ready(sk)) 865 sk->sk_data_ready(sk); 866 mptcp_data_unlock(sk); 867 } 868 869 static void mptcp_subflow_joined(struct mptcp_sock *msk, struct sock *ssk) 870 { 871 mptcp_subflow_ctx(ssk)->map_seq = READ_ONCE(msk->ack_seq); 872 WRITE_ONCE(msk->allow_infinite_fallback, false); 873 mptcp_event(MPTCP_EVENT_SUB_ESTABLISHED, msk, ssk, GFP_ATOMIC); 874 } 875 876 static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk) 877 { 878 struct sock *sk = (struct sock *)msk; 879 880 if (sk->sk_state != TCP_ESTABLISHED) 881 return false; 882 883 /* attach to msk socket only after we are sure we will deal with it 884 * at close time 885 */ 886 if (sk->sk_socket && !ssk->sk_socket) 887 mptcp_sock_graft(ssk, sk->sk_socket); 888 889 mptcp_subflow_ctx(ssk)->subflow_id = msk->subflow_id++; 890 mptcp_sockopt_sync_locked(msk, ssk); 891 mptcp_subflow_joined(msk, ssk); 892 mptcp_stop_tout_timer(sk); 893 __mptcp_propagate_sndbuf(sk, ssk); 894 return true; 895 } 896 897 static void __mptcp_flush_join_list(struct sock *sk, struct list_head *join_list) 898 { 899 struct mptcp_subflow_context *tmp, *subflow; 900 struct mptcp_sock *msk = mptcp_sk(sk); 901 902 list_for_each_entry_safe(subflow, tmp, join_list, node) { 903 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 904 bool slow = lock_sock_fast(ssk); 905 906 list_move_tail(&subflow->node, &msk->conn_list); 907 if (!__mptcp_finish_join(msk, ssk)) 908 mptcp_subflow_reset(ssk); 909 unlock_sock_fast(ssk, slow); 910 } 911 } 912 913 static bool mptcp_rtx_timer_pending(struct sock *sk) 914 { 915 return timer_pending(&inet_csk(sk)->icsk_retransmit_timer); 916 } 917 918 static void mptcp_reset_rtx_timer(struct sock *sk) 919 { 920 struct inet_connection_sock *icsk = inet_csk(sk); 921 unsigned long tout; 922 923 /* prevent rescheduling on close */ 924 if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) 925 return; 926 927 tout = mptcp_sk(sk)->timer_ival; 928 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + tout); 929 } 930 931 bool mptcp_schedule_work(struct sock *sk) 932 { 933 if (inet_sk_state_load(sk) != TCP_CLOSE && 934 schedule_work(&mptcp_sk(sk)->work)) { 935 /* each subflow already holds a reference to the sk, and the 936 * workqueue is invoked by a subflow, so sk can't go away here. 937 */ 938 sock_hold(sk); 939 return true; 940 } 941 return false; 942 } 943 944 static struct sock *mptcp_subflow_recv_lookup(const struct mptcp_sock *msk) 945 { 946 struct mptcp_subflow_context *subflow; 947 948 msk_owned_by_me(msk); 949 950 mptcp_for_each_subflow(msk, subflow) { 951 if (READ_ONCE(subflow->data_avail)) 952 return mptcp_subflow_tcp_sock(subflow); 953 } 954 955 return NULL; 956 } 957 958 static bool mptcp_skb_can_collapse_to(u64 write_seq, 959 const struct sk_buff *skb, 960 const struct mptcp_ext *mpext) 961 { 962 if (!tcp_skb_can_collapse_to(skb)) 963 return false; 964 965 /* can collapse only if MPTCP level sequence is in order and this 966 * mapping has not been xmitted yet 967 */ 968 return mpext && mpext->data_seq + mpext->data_len == write_seq && 969 !mpext->frozen; 970 } 971 972 /* we can append data to the given data frag if: 973 * - there is space available in the backing page_frag 974 * - the data frag tail matches the current page_frag free offset 975 * - the data frag end sequence number matches the current write seq 976 */ 977 static bool mptcp_frag_can_collapse_to(const struct mptcp_sock *msk, 978 const struct page_frag *pfrag, 979 const struct mptcp_data_frag *df) 980 { 981 return df && pfrag->page == df->page && 982 pfrag->size - pfrag->offset > 0 && 983 pfrag->offset == (df->offset + df->data_len) && 984 df->data_seq + df->data_len == msk->write_seq; 985 } 986 987 static void dfrag_uncharge(struct sock *sk, int len) 988 { 989 sk_mem_uncharge(sk, len); 990 sk_wmem_queued_add(sk, -len); 991 } 992 993 static void dfrag_clear(struct sock *sk, struct mptcp_data_frag *dfrag) 994 { 995 int len = dfrag->data_len + dfrag->overhead; 996 997 list_del(&dfrag->list); 998 dfrag_uncharge(sk, len); 999 put_page(dfrag->page); 1000 } 1001 1002 static void __mptcp_clean_una(struct sock *sk) 1003 { 1004 struct mptcp_sock *msk = mptcp_sk(sk); 1005 struct mptcp_data_frag *dtmp, *dfrag; 1006 u64 snd_una; 1007 1008 snd_una = msk->snd_una; 1009 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) { 1010 if (after64(dfrag->data_seq + dfrag->data_len, snd_una)) 1011 break; 1012 1013 if (unlikely(dfrag == msk->first_pending)) { 1014 /* in recovery mode can see ack after the current snd head */ 1015 if (WARN_ON_ONCE(!msk->recovery)) 1016 break; 1017 1018 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1019 } 1020 1021 dfrag_clear(sk, dfrag); 1022 } 1023 1024 dfrag = mptcp_rtx_head(sk); 1025 if (dfrag && after64(snd_una, dfrag->data_seq)) { 1026 u64 delta = snd_una - dfrag->data_seq; 1027 1028 /* prevent wrap around in recovery mode */ 1029 if (unlikely(delta > dfrag->already_sent)) { 1030 if (WARN_ON_ONCE(!msk->recovery)) 1031 goto out; 1032 if (WARN_ON_ONCE(delta > dfrag->data_len)) 1033 goto out; 1034 dfrag->already_sent += delta - dfrag->already_sent; 1035 } 1036 1037 dfrag->data_seq += delta; 1038 dfrag->offset += delta; 1039 dfrag->data_len -= delta; 1040 dfrag->already_sent -= delta; 1041 1042 dfrag_uncharge(sk, delta); 1043 } 1044 1045 /* all retransmitted data acked, recovery completed */ 1046 if (unlikely(msk->recovery) && after64(msk->snd_una, msk->recovery_snd_nxt)) 1047 msk->recovery = false; 1048 1049 out: 1050 if (snd_una == READ_ONCE(msk->snd_nxt) && 1051 snd_una == READ_ONCE(msk->write_seq)) { 1052 if (mptcp_rtx_timer_pending(sk) && !mptcp_data_fin_enabled(msk)) 1053 mptcp_stop_rtx_timer(sk); 1054 } else { 1055 mptcp_reset_rtx_timer(sk); 1056 } 1057 } 1058 1059 static void __mptcp_clean_una_wakeup(struct sock *sk) 1060 { 1061 lockdep_assert_held_once(&sk->sk_lock.slock); 1062 1063 __mptcp_clean_una(sk); 1064 mptcp_write_space(sk); 1065 } 1066 1067 static void mptcp_clean_una_wakeup(struct sock *sk) 1068 { 1069 mptcp_data_lock(sk); 1070 __mptcp_clean_una_wakeup(sk); 1071 mptcp_data_unlock(sk); 1072 } 1073 1074 static void mptcp_enter_memory_pressure(struct sock *sk) 1075 { 1076 struct mptcp_subflow_context *subflow; 1077 struct mptcp_sock *msk = mptcp_sk(sk); 1078 bool first = true; 1079 1080 mptcp_for_each_subflow(msk, subflow) { 1081 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 1082 1083 if (first) 1084 tcp_enter_memory_pressure(ssk); 1085 sk_stream_moderate_sndbuf(ssk); 1086 1087 first = false; 1088 } 1089 __mptcp_sync_sndbuf(sk); 1090 } 1091 1092 /* ensure we get enough memory for the frag hdr, beyond some minimal amount of 1093 * data 1094 */ 1095 static bool mptcp_page_frag_refill(struct sock *sk, struct page_frag *pfrag) 1096 { 1097 if (likely(skb_page_frag_refill(32U + sizeof(struct mptcp_data_frag), 1098 pfrag, sk->sk_allocation))) 1099 return true; 1100 1101 mptcp_enter_memory_pressure(sk); 1102 return false; 1103 } 1104 1105 static struct mptcp_data_frag * 1106 mptcp_carve_data_frag(const struct mptcp_sock *msk, struct page_frag *pfrag, 1107 int orig_offset) 1108 { 1109 int offset = ALIGN(orig_offset, sizeof(long)); 1110 struct mptcp_data_frag *dfrag; 1111 1112 dfrag = (struct mptcp_data_frag *)(page_to_virt(pfrag->page) + offset); 1113 dfrag->data_len = 0; 1114 dfrag->data_seq = msk->write_seq; 1115 dfrag->overhead = offset - orig_offset + sizeof(struct mptcp_data_frag); 1116 dfrag->offset = offset + sizeof(struct mptcp_data_frag); 1117 dfrag->already_sent = 0; 1118 dfrag->page = pfrag->page; 1119 1120 return dfrag; 1121 } 1122 1123 struct mptcp_sendmsg_info { 1124 int mss_now; 1125 int size_goal; 1126 u16 limit; 1127 u16 sent; 1128 unsigned int flags; 1129 bool data_lock_held; 1130 }; 1131 1132 static int mptcp_check_allowed_size(const struct mptcp_sock *msk, struct sock *ssk, 1133 u64 data_seq, int avail_size) 1134 { 1135 u64 window_end = mptcp_wnd_end(msk); 1136 u64 mptcp_snd_wnd; 1137 1138 if (__mptcp_check_fallback(msk)) 1139 return avail_size; 1140 1141 mptcp_snd_wnd = window_end - data_seq; 1142 avail_size = min_t(unsigned int, mptcp_snd_wnd, avail_size); 1143 1144 if (unlikely(tcp_sk(ssk)->snd_wnd < mptcp_snd_wnd)) { 1145 tcp_sk(ssk)->snd_wnd = min_t(u64, U32_MAX, mptcp_snd_wnd); 1146 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_SNDWNDSHARED); 1147 } 1148 1149 return avail_size; 1150 } 1151 1152 static bool __mptcp_add_ext(struct sk_buff *skb, gfp_t gfp) 1153 { 1154 struct skb_ext *mpext = __skb_ext_alloc(gfp); 1155 1156 if (!mpext) 1157 return false; 1158 __skb_ext_set(skb, SKB_EXT_MPTCP, mpext); 1159 return true; 1160 } 1161 1162 static struct sk_buff *__mptcp_do_alloc_tx_skb(struct sock *sk, gfp_t gfp) 1163 { 1164 struct sk_buff *skb; 1165 1166 skb = alloc_skb_fclone(MAX_TCP_HEADER, gfp); 1167 if (likely(skb)) { 1168 if (likely(__mptcp_add_ext(skb, gfp))) { 1169 skb_reserve(skb, MAX_TCP_HEADER); 1170 skb->ip_summed = CHECKSUM_PARTIAL; 1171 INIT_LIST_HEAD(&skb->tcp_tsorted_anchor); 1172 return skb; 1173 } 1174 __kfree_skb(skb); 1175 } else { 1176 mptcp_enter_memory_pressure(sk); 1177 } 1178 return NULL; 1179 } 1180 1181 static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, gfp_t gfp) 1182 { 1183 struct sk_buff *skb; 1184 1185 skb = __mptcp_do_alloc_tx_skb(sk, gfp); 1186 if (!skb) 1187 return NULL; 1188 1189 if (likely(sk_wmem_schedule(ssk, skb->truesize))) { 1190 tcp_skb_entail(ssk, skb); 1191 return skb; 1192 } 1193 tcp_skb_tsorted_anchor_cleanup(skb); 1194 kfree_skb(skb); 1195 return NULL; 1196 } 1197 1198 static struct sk_buff *mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, bool data_lock_held) 1199 { 1200 gfp_t gfp = data_lock_held ? GFP_ATOMIC : sk->sk_allocation; 1201 1202 return __mptcp_alloc_tx_skb(sk, ssk, gfp); 1203 } 1204 1205 /* note: this always recompute the csum on the whole skb, even 1206 * if we just appended a single frag. More status info needed 1207 */ 1208 static void mptcp_update_data_checksum(struct sk_buff *skb, int added) 1209 { 1210 struct mptcp_ext *mpext = mptcp_get_ext(skb); 1211 __wsum csum = ~csum_unfold(mpext->csum); 1212 int offset = skb->len - added; 1213 1214 mpext->csum = csum_fold(csum_block_add(csum, skb_checksum(skb, offset, added, 0), offset)); 1215 } 1216 1217 static void mptcp_update_infinite_map(struct mptcp_sock *msk, 1218 struct sock *ssk, 1219 struct mptcp_ext *mpext) 1220 { 1221 if (!mpext) 1222 return; 1223 1224 mpext->infinite_map = 1; 1225 mpext->data_len = 0; 1226 1227 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); 1228 mptcp_subflow_ctx(ssk)->send_infinite_map = 0; 1229 pr_fallback(msk); 1230 mptcp_do_fallback(ssk); 1231 } 1232 1233 #define MPTCP_MAX_GSO_SIZE (GSO_LEGACY_MAX_SIZE - (MAX_TCP_HEADER + 1)) 1234 1235 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 1236 struct mptcp_data_frag *dfrag, 1237 struct mptcp_sendmsg_info *info) 1238 { 1239 u64 data_seq = dfrag->data_seq + info->sent; 1240 int offset = dfrag->offset + info->sent; 1241 struct mptcp_sock *msk = mptcp_sk(sk); 1242 bool zero_window_probe = false; 1243 struct mptcp_ext *mpext = NULL; 1244 bool can_coalesce = false; 1245 bool reuse_skb = true; 1246 struct sk_buff *skb; 1247 size_t copy; 1248 int i; 1249 1250 pr_debug("msk=%p ssk=%p sending dfrag at seq=%llu len=%u already sent=%u", 1251 msk, ssk, dfrag->data_seq, dfrag->data_len, info->sent); 1252 1253 if (WARN_ON_ONCE(info->sent > info->limit || 1254 info->limit > dfrag->data_len)) 1255 return 0; 1256 1257 if (unlikely(!__tcp_can_send(ssk))) 1258 return -EAGAIN; 1259 1260 /* compute send limit */ 1261 if (unlikely(ssk->sk_gso_max_size > MPTCP_MAX_GSO_SIZE)) 1262 ssk->sk_gso_max_size = MPTCP_MAX_GSO_SIZE; 1263 info->mss_now = tcp_send_mss(ssk, &info->size_goal, info->flags); 1264 copy = info->size_goal; 1265 1266 skb = tcp_write_queue_tail(ssk); 1267 if (skb && copy > skb->len) { 1268 /* Limit the write to the size available in the 1269 * current skb, if any, so that we create at most a new skb. 1270 * Explicitly tells TCP internals to avoid collapsing on later 1271 * queue management operation, to avoid breaking the ext <-> 1272 * SSN association set here 1273 */ 1274 mpext = mptcp_get_ext(skb); 1275 if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) { 1276 TCP_SKB_CB(skb)->eor = 1; 1277 goto alloc_skb; 1278 } 1279 1280 i = skb_shinfo(skb)->nr_frags; 1281 can_coalesce = skb_can_coalesce(skb, i, dfrag->page, offset); 1282 if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) { 1283 tcp_mark_push(tcp_sk(ssk), skb); 1284 goto alloc_skb; 1285 } 1286 1287 copy -= skb->len; 1288 } else { 1289 alloc_skb: 1290 skb = mptcp_alloc_tx_skb(sk, ssk, info->data_lock_held); 1291 if (!skb) 1292 return -ENOMEM; 1293 1294 i = skb_shinfo(skb)->nr_frags; 1295 reuse_skb = false; 1296 mpext = mptcp_get_ext(skb); 1297 } 1298 1299 /* Zero window and all data acked? Probe. */ 1300 copy = mptcp_check_allowed_size(msk, ssk, data_seq, copy); 1301 if (copy == 0) { 1302 u64 snd_una = READ_ONCE(msk->snd_una); 1303 1304 if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) { 1305 tcp_remove_empty_skb(ssk); 1306 return 0; 1307 } 1308 1309 zero_window_probe = true; 1310 data_seq = snd_una - 1; 1311 copy = 1; 1312 } 1313 1314 copy = min_t(size_t, copy, info->limit - info->sent); 1315 if (!sk_wmem_schedule(ssk, copy)) { 1316 tcp_remove_empty_skb(ssk); 1317 return -ENOMEM; 1318 } 1319 1320 if (can_coalesce) { 1321 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); 1322 } else { 1323 get_page(dfrag->page); 1324 skb_fill_page_desc(skb, i, dfrag->page, offset, copy); 1325 } 1326 1327 skb->len += copy; 1328 skb->data_len += copy; 1329 skb->truesize += copy; 1330 sk_wmem_queued_add(ssk, copy); 1331 sk_mem_charge(ssk, copy); 1332 WRITE_ONCE(tcp_sk(ssk)->write_seq, tcp_sk(ssk)->write_seq + copy); 1333 TCP_SKB_CB(skb)->end_seq += copy; 1334 tcp_skb_pcount_set(skb, 0); 1335 1336 /* on skb reuse we just need to update the DSS len */ 1337 if (reuse_skb) { 1338 TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH; 1339 mpext->data_len += copy; 1340 goto out; 1341 } 1342 1343 memset(mpext, 0, sizeof(*mpext)); 1344 mpext->data_seq = data_seq; 1345 mpext->subflow_seq = mptcp_subflow_ctx(ssk)->rel_write_seq; 1346 mpext->data_len = copy; 1347 mpext->use_map = 1; 1348 mpext->dsn64 = 1; 1349 1350 pr_debug("data_seq=%llu subflow_seq=%u data_len=%u dsn64=%d", 1351 mpext->data_seq, mpext->subflow_seq, mpext->data_len, 1352 mpext->dsn64); 1353 1354 if (zero_window_probe) { 1355 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1356 mpext->frozen = 1; 1357 if (READ_ONCE(msk->csum_enabled)) 1358 mptcp_update_data_checksum(skb, copy); 1359 tcp_push_pending_frames(ssk); 1360 return 0; 1361 } 1362 out: 1363 if (READ_ONCE(msk->csum_enabled)) 1364 mptcp_update_data_checksum(skb, copy); 1365 if (mptcp_subflow_ctx(ssk)->send_infinite_map) 1366 mptcp_update_infinite_map(msk, ssk, mpext); 1367 trace_mptcp_sendmsg_frag(mpext); 1368 mptcp_subflow_ctx(ssk)->rel_write_seq += copy; 1369 return copy; 1370 } 1371 1372 #define MPTCP_SEND_BURST_SIZE ((1 << 16) - \ 1373 sizeof(struct tcphdr) - \ 1374 MAX_TCP_OPTION_SPACE - \ 1375 sizeof(struct ipv6hdr) - \ 1376 sizeof(struct frag_hdr)) 1377 1378 struct subflow_send_info { 1379 struct sock *ssk; 1380 u64 linger_time; 1381 }; 1382 1383 void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow) 1384 { 1385 if (!subflow->stale) 1386 return; 1387 1388 subflow->stale = 0; 1389 MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER); 1390 } 1391 1392 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) 1393 { 1394 if (unlikely(subflow->stale)) { 1395 u32 rcv_tstamp = READ_ONCE(tcp_sk(mptcp_subflow_tcp_sock(subflow))->rcv_tstamp); 1396 1397 if (subflow->stale_rcv_tstamp == rcv_tstamp) 1398 return false; 1399 1400 mptcp_subflow_set_active(subflow); 1401 } 1402 return __mptcp_subflow_active(subflow); 1403 } 1404 1405 #define SSK_MODE_ACTIVE 0 1406 #define SSK_MODE_BACKUP 1 1407 #define SSK_MODE_MAX 2 1408 1409 /* implement the mptcp packet scheduler; 1410 * returns the subflow that will transmit the next DSS 1411 * additionally updates the rtx timeout 1412 */ 1413 struct sock *mptcp_subflow_get_send(struct mptcp_sock *msk) 1414 { 1415 struct subflow_send_info send_info[SSK_MODE_MAX]; 1416 struct mptcp_subflow_context *subflow; 1417 struct sock *sk = (struct sock *)msk; 1418 u32 pace, burst, wmem; 1419 int i, nr_active = 0; 1420 struct sock *ssk; 1421 u64 linger_time; 1422 long tout = 0; 1423 1424 /* pick the subflow with the lower wmem/wspace ratio */ 1425 for (i = 0; i < SSK_MODE_MAX; ++i) { 1426 send_info[i].ssk = NULL; 1427 send_info[i].linger_time = -1; 1428 } 1429 1430 mptcp_for_each_subflow(msk, subflow) { 1431 trace_mptcp_subflow_get_send(subflow); 1432 ssk = mptcp_subflow_tcp_sock(subflow); 1433 if (!mptcp_subflow_active(subflow)) 1434 continue; 1435 1436 tout = max(tout, mptcp_timeout_from_subflow(subflow)); 1437 nr_active += !subflow->backup; 1438 pace = subflow->avg_pacing_rate; 1439 if (unlikely(!pace)) { 1440 /* init pacing rate from socket */ 1441 subflow->avg_pacing_rate = READ_ONCE(ssk->sk_pacing_rate); 1442 pace = subflow->avg_pacing_rate; 1443 if (!pace) 1444 continue; 1445 } 1446 1447 linger_time = div_u64((u64)READ_ONCE(ssk->sk_wmem_queued) << 32, pace); 1448 if (linger_time < send_info[subflow->backup].linger_time) { 1449 send_info[subflow->backup].ssk = ssk; 1450 send_info[subflow->backup].linger_time = linger_time; 1451 } 1452 } 1453 __mptcp_set_timeout(sk, tout); 1454 1455 /* pick the best backup if no other subflow is active */ 1456 if (!nr_active) 1457 send_info[SSK_MODE_ACTIVE].ssk = send_info[SSK_MODE_BACKUP].ssk; 1458 1459 /* According to the blest algorithm, to avoid HoL blocking for the 1460 * faster flow, we need to: 1461 * - estimate the faster flow linger time 1462 * - use the above to estimate the amount of byte transferred 1463 * by the faster flow 1464 * - check that the amount of queued data is greter than the above, 1465 * otherwise do not use the picked, slower, subflow 1466 * We select the subflow with the shorter estimated time to flush 1467 * the queued mem, which basically ensure the above. We just need 1468 * to check that subflow has a non empty cwin. 1469 */ 1470 ssk = send_info[SSK_MODE_ACTIVE].ssk; 1471 if (!ssk || !sk_stream_memory_free(ssk)) 1472 return NULL; 1473 1474 burst = min_t(int, MPTCP_SEND_BURST_SIZE, mptcp_wnd_end(msk) - msk->snd_nxt); 1475 wmem = READ_ONCE(ssk->sk_wmem_queued); 1476 if (!burst) 1477 return ssk; 1478 1479 subflow = mptcp_subflow_ctx(ssk); 1480 subflow->avg_pacing_rate = div_u64((u64)subflow->avg_pacing_rate * wmem + 1481 READ_ONCE(ssk->sk_pacing_rate) * burst, 1482 burst + wmem); 1483 msk->snd_burst = burst; 1484 return ssk; 1485 } 1486 1487 static void mptcp_push_release(struct sock *ssk, struct mptcp_sendmsg_info *info) 1488 { 1489 tcp_push(ssk, 0, info->mss_now, tcp_sk(ssk)->nonagle, info->size_goal); 1490 release_sock(ssk); 1491 } 1492 1493 static void mptcp_update_post_push(struct mptcp_sock *msk, 1494 struct mptcp_data_frag *dfrag, 1495 u32 sent) 1496 { 1497 u64 snd_nxt_new = dfrag->data_seq; 1498 1499 dfrag->already_sent += sent; 1500 1501 msk->snd_burst -= sent; 1502 1503 snd_nxt_new += dfrag->already_sent; 1504 1505 /* snd_nxt_new can be smaller than snd_nxt in case mptcp 1506 * is recovering after a failover. In that event, this re-sends 1507 * old segments. 1508 * 1509 * Thus compute snd_nxt_new candidate based on 1510 * the dfrag->data_seq that was sent and the data 1511 * that has been handed to the subflow for transmission 1512 * and skip update in case it was old dfrag. 1513 */ 1514 if (likely(after64(snd_nxt_new, msk->snd_nxt))) { 1515 msk->bytes_sent += snd_nxt_new - msk->snd_nxt; 1516 msk->snd_nxt = snd_nxt_new; 1517 } 1518 } 1519 1520 void mptcp_check_and_set_pending(struct sock *sk) 1521 { 1522 if (mptcp_send_head(sk)) 1523 mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING); 1524 } 1525 1526 static int __subflow_push_pending(struct sock *sk, struct sock *ssk, 1527 struct mptcp_sendmsg_info *info) 1528 { 1529 struct mptcp_sock *msk = mptcp_sk(sk); 1530 struct mptcp_data_frag *dfrag; 1531 int len, copied = 0, err = 0; 1532 1533 while ((dfrag = mptcp_send_head(sk))) { 1534 info->sent = dfrag->already_sent; 1535 info->limit = dfrag->data_len; 1536 len = dfrag->data_len - dfrag->already_sent; 1537 while (len > 0) { 1538 int ret = 0; 1539 1540 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, info); 1541 if (ret <= 0) { 1542 err = copied ? : ret; 1543 goto out; 1544 } 1545 1546 info->sent += ret; 1547 copied += ret; 1548 len -= ret; 1549 1550 mptcp_update_post_push(msk, dfrag, ret); 1551 } 1552 WRITE_ONCE(msk->first_pending, mptcp_send_next(sk)); 1553 1554 if (msk->snd_burst <= 0 || 1555 !sk_stream_memory_free(ssk) || 1556 !mptcp_subflow_active(mptcp_subflow_ctx(ssk))) { 1557 err = copied; 1558 goto out; 1559 } 1560 mptcp_set_timeout(sk); 1561 } 1562 err = copied; 1563 1564 out: 1565 return err; 1566 } 1567 1568 void __mptcp_push_pending(struct sock *sk, unsigned int flags) 1569 { 1570 struct sock *prev_ssk = NULL, *ssk = NULL; 1571 struct mptcp_sock *msk = mptcp_sk(sk); 1572 struct mptcp_sendmsg_info info = { 1573 .flags = flags, 1574 }; 1575 bool do_check_data_fin = false; 1576 int push_count = 1; 1577 1578 while (mptcp_send_head(sk) && (push_count > 0)) { 1579 struct mptcp_subflow_context *subflow; 1580 int ret = 0; 1581 1582 if (mptcp_sched_get_send(msk)) 1583 break; 1584 1585 push_count = 0; 1586 1587 mptcp_for_each_subflow(msk, subflow) { 1588 if (READ_ONCE(subflow->scheduled)) { 1589 mptcp_subflow_set_scheduled(subflow, false); 1590 1591 prev_ssk = ssk; 1592 ssk = mptcp_subflow_tcp_sock(subflow); 1593 if (ssk != prev_ssk) { 1594 /* First check. If the ssk has changed since 1595 * the last round, release prev_ssk 1596 */ 1597 if (prev_ssk) 1598 mptcp_push_release(prev_ssk, &info); 1599 1600 /* Need to lock the new subflow only if different 1601 * from the previous one, otherwise we are still 1602 * helding the relevant lock 1603 */ 1604 lock_sock(ssk); 1605 } 1606 1607 push_count++; 1608 1609 ret = __subflow_push_pending(sk, ssk, &info); 1610 if (ret <= 0) { 1611 if (ret != -EAGAIN || 1612 (1 << ssk->sk_state) & 1613 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSE)) 1614 push_count--; 1615 continue; 1616 } 1617 do_check_data_fin = true; 1618 } 1619 } 1620 } 1621 1622 /* at this point we held the socket lock for the last subflow we used */ 1623 if (ssk) 1624 mptcp_push_release(ssk, &info); 1625 1626 /* ensure the rtx timer is running */ 1627 if (!mptcp_rtx_timer_pending(sk)) 1628 mptcp_reset_rtx_timer(sk); 1629 if (do_check_data_fin) 1630 mptcp_check_send_data_fin(sk); 1631 } 1632 1633 static void __mptcp_subflow_push_pending(struct sock *sk, struct sock *ssk, bool first) 1634 { 1635 struct mptcp_sock *msk = mptcp_sk(sk); 1636 struct mptcp_sendmsg_info info = { 1637 .data_lock_held = true, 1638 }; 1639 bool keep_pushing = true; 1640 struct sock *xmit_ssk; 1641 int copied = 0; 1642 1643 info.flags = 0; 1644 while (mptcp_send_head(sk) && keep_pushing) { 1645 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 1646 int ret = 0; 1647 1648 /* check for a different subflow usage only after 1649 * spooling the first chunk of data 1650 */ 1651 if (first) { 1652 mptcp_subflow_set_scheduled(subflow, false); 1653 ret = __subflow_push_pending(sk, ssk, &info); 1654 first = false; 1655 if (ret <= 0) 1656 break; 1657 copied += ret; 1658 continue; 1659 } 1660 1661 if (mptcp_sched_get_send(msk)) 1662 goto out; 1663 1664 if (READ_ONCE(subflow->scheduled)) { 1665 mptcp_subflow_set_scheduled(subflow, false); 1666 ret = __subflow_push_pending(sk, ssk, &info); 1667 if (ret <= 0) 1668 keep_pushing = false; 1669 copied += ret; 1670 } 1671 1672 mptcp_for_each_subflow(msk, subflow) { 1673 if (READ_ONCE(subflow->scheduled)) { 1674 xmit_ssk = mptcp_subflow_tcp_sock(subflow); 1675 if (xmit_ssk != ssk) { 1676 mptcp_subflow_delegate(subflow, 1677 MPTCP_DELEGATE_SEND); 1678 keep_pushing = false; 1679 } 1680 } 1681 } 1682 } 1683 1684 out: 1685 /* __mptcp_alloc_tx_skb could have released some wmem and we are 1686 * not going to flush it via release_sock() 1687 */ 1688 if (copied) { 1689 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 1690 info.size_goal); 1691 if (!mptcp_rtx_timer_pending(sk)) 1692 mptcp_reset_rtx_timer(sk); 1693 1694 if (msk->snd_data_fin_enable && 1695 msk->snd_nxt + 1 == msk->write_seq) 1696 mptcp_schedule_work(sk); 1697 } 1698 } 1699 1700 static void mptcp_set_nospace(struct sock *sk) 1701 { 1702 /* enable autotune */ 1703 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); 1704 1705 /* will be cleared on avail space */ 1706 set_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags); 1707 } 1708 1709 static int mptcp_disconnect(struct sock *sk, int flags); 1710 1711 static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, 1712 size_t len, int *copied_syn) 1713 { 1714 unsigned int saved_flags = msg->msg_flags; 1715 struct mptcp_sock *msk = mptcp_sk(sk); 1716 struct sock *ssk; 1717 int ret; 1718 1719 /* on flags based fastopen the mptcp is supposed to create the 1720 * first subflow right now. Otherwise we are in the defer_connect 1721 * path, and the first subflow must be already present. 1722 * Since the defer_connect flag is cleared after the first succsful 1723 * fastopen attempt, no need to check for additional subflow status. 1724 */ 1725 if (msg->msg_flags & MSG_FASTOPEN) { 1726 ssk = __mptcp_nmpc_sk(msk); 1727 if (IS_ERR(ssk)) 1728 return PTR_ERR(ssk); 1729 } 1730 if (!msk->first) 1731 return -EINVAL; 1732 1733 ssk = msk->first; 1734 1735 lock_sock(ssk); 1736 msg->msg_flags |= MSG_DONTWAIT; 1737 msk->fastopening = 1; 1738 ret = tcp_sendmsg_fastopen(ssk, msg, copied_syn, len, NULL); 1739 msk->fastopening = 0; 1740 msg->msg_flags = saved_flags; 1741 release_sock(ssk); 1742 1743 /* do the blocking bits of inet_stream_connect outside the ssk socket lock */ 1744 if (ret == -EINPROGRESS && !(msg->msg_flags & MSG_DONTWAIT)) { 1745 ret = __inet_stream_connect(sk->sk_socket, msg->msg_name, 1746 msg->msg_namelen, msg->msg_flags, 1); 1747 1748 /* Keep the same behaviour of plain TCP: zero the copied bytes in 1749 * case of any error, except timeout or signal 1750 */ 1751 if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) 1752 *copied_syn = 0; 1753 } else if (ret && ret != -EINPROGRESS) { 1754 /* The disconnect() op called by tcp_sendmsg_fastopen()/ 1755 * __inet_stream_connect() can fail, due to looking check, 1756 * see mptcp_disconnect(). 1757 * Attempt it again outside the problematic scope. 1758 */ 1759 if (!mptcp_disconnect(sk, 0)) 1760 sk->sk_socket->state = SS_UNCONNECTED; 1761 } 1762 inet_clear_bit(DEFER_CONNECT, sk); 1763 1764 return ret; 1765 } 1766 1767 static int do_copy_data_nocache(struct sock *sk, int copy, 1768 struct iov_iter *from, char *to) 1769 { 1770 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) { 1771 if (!copy_from_iter_full_nocache(to, copy, from)) 1772 return -EFAULT; 1773 } else if (!copy_from_iter_full(to, copy, from)) { 1774 return -EFAULT; 1775 } 1776 return 0; 1777 } 1778 1779 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 1780 { 1781 struct mptcp_sock *msk = mptcp_sk(sk); 1782 struct page_frag *pfrag; 1783 size_t copied = 0; 1784 int ret = 0; 1785 long timeo; 1786 1787 /* silently ignore everything else */ 1788 msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_FASTOPEN; 1789 1790 lock_sock(sk); 1791 1792 if (unlikely(inet_test_bit(DEFER_CONNECT, sk) || 1793 msg->msg_flags & MSG_FASTOPEN)) { 1794 int copied_syn = 0; 1795 1796 ret = mptcp_sendmsg_fastopen(sk, msg, len, &copied_syn); 1797 copied += copied_syn; 1798 if (ret == -EINPROGRESS && copied_syn > 0) 1799 goto out; 1800 else if (ret) 1801 goto do_error; 1802 } 1803 1804 timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); 1805 1806 if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { 1807 ret = sk_stream_wait_connect(sk, &timeo); 1808 if (ret) 1809 goto do_error; 1810 } 1811 1812 ret = -EPIPE; 1813 if (unlikely(sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))) 1814 goto do_error; 1815 1816 pfrag = sk_page_frag(sk); 1817 1818 while (msg_data_left(msg)) { 1819 int total_ts, frag_truesize = 0; 1820 struct mptcp_data_frag *dfrag; 1821 bool dfrag_collapsed; 1822 size_t psize, offset; 1823 1824 /* reuse tail pfrag, if possible, or carve a new one from the 1825 * page allocator 1826 */ 1827 dfrag = mptcp_pending_tail(sk); 1828 dfrag_collapsed = mptcp_frag_can_collapse_to(msk, pfrag, dfrag); 1829 if (!dfrag_collapsed) { 1830 if (!sk_stream_memory_free(sk)) 1831 goto wait_for_memory; 1832 1833 if (!mptcp_page_frag_refill(sk, pfrag)) 1834 goto wait_for_memory; 1835 1836 dfrag = mptcp_carve_data_frag(msk, pfrag, pfrag->offset); 1837 frag_truesize = dfrag->overhead; 1838 } 1839 1840 /* we do not bound vs wspace, to allow a single packet. 1841 * memory accounting will prevent execessive memory usage 1842 * anyway 1843 */ 1844 offset = dfrag->offset + dfrag->data_len; 1845 psize = pfrag->size - offset; 1846 psize = min_t(size_t, psize, msg_data_left(msg)); 1847 total_ts = psize + frag_truesize; 1848 1849 if (!sk_wmem_schedule(sk, total_ts)) 1850 goto wait_for_memory; 1851 1852 ret = do_copy_data_nocache(sk, psize, &msg->msg_iter, 1853 page_address(dfrag->page) + offset); 1854 if (ret) 1855 goto do_error; 1856 1857 /* data successfully copied into the write queue */ 1858 sk_forward_alloc_add(sk, -total_ts); 1859 copied += psize; 1860 dfrag->data_len += psize; 1861 frag_truesize += psize; 1862 pfrag->offset += frag_truesize; 1863 WRITE_ONCE(msk->write_seq, msk->write_seq + psize); 1864 1865 /* charge data on mptcp pending queue to the msk socket 1866 * Note: we charge such data both to sk and ssk 1867 */ 1868 sk_wmem_queued_add(sk, frag_truesize); 1869 if (!dfrag_collapsed) { 1870 get_page(dfrag->page); 1871 list_add_tail(&dfrag->list, &msk->rtx_queue); 1872 if (!msk->first_pending) 1873 WRITE_ONCE(msk->first_pending, dfrag); 1874 } 1875 pr_debug("msk=%p dfrag at seq=%llu len=%u sent=%u new=%d", msk, 1876 dfrag->data_seq, dfrag->data_len, dfrag->already_sent, 1877 !dfrag_collapsed); 1878 1879 continue; 1880 1881 wait_for_memory: 1882 mptcp_set_nospace(sk); 1883 __mptcp_push_pending(sk, msg->msg_flags); 1884 ret = sk_stream_wait_memory(sk, &timeo); 1885 if (ret) 1886 goto do_error; 1887 } 1888 1889 if (copied) 1890 __mptcp_push_pending(sk, msg->msg_flags); 1891 1892 out: 1893 release_sock(sk); 1894 return copied; 1895 1896 do_error: 1897 if (copied) 1898 goto out; 1899 1900 copied = sk_stream_error(sk, msg->msg_flags, ret); 1901 goto out; 1902 } 1903 1904 static int __mptcp_recvmsg_mskq(struct mptcp_sock *msk, 1905 struct msghdr *msg, 1906 size_t len, int flags, 1907 struct scm_timestamping_internal *tss, 1908 int *cmsg_flags) 1909 { 1910 struct sk_buff *skb, *tmp; 1911 int copied = 0; 1912 1913 skb_queue_walk_safe(&msk->receive_queue, skb, tmp) { 1914 u32 offset = MPTCP_SKB_CB(skb)->offset; 1915 u32 data_len = skb->len - offset; 1916 u32 count = min_t(size_t, len - copied, data_len); 1917 int err; 1918 1919 if (!(flags & MSG_TRUNC)) { 1920 err = skb_copy_datagram_msg(skb, offset, msg, count); 1921 if (unlikely(err < 0)) { 1922 if (!copied) 1923 return err; 1924 break; 1925 } 1926 } 1927 1928 if (MPTCP_SKB_CB(skb)->has_rxtstamp) { 1929 tcp_update_recv_tstamps(skb, tss); 1930 *cmsg_flags |= MPTCP_CMSG_TS; 1931 } 1932 1933 copied += count; 1934 1935 if (count < data_len) { 1936 if (!(flags & MSG_PEEK)) { 1937 MPTCP_SKB_CB(skb)->offset += count; 1938 MPTCP_SKB_CB(skb)->map_seq += count; 1939 msk->bytes_consumed += count; 1940 } 1941 break; 1942 } 1943 1944 if (!(flags & MSG_PEEK)) { 1945 /* we will bulk release the skb memory later */ 1946 skb->destructor = NULL; 1947 WRITE_ONCE(msk->rmem_released, msk->rmem_released + skb->truesize); 1948 __skb_unlink(skb, &msk->receive_queue); 1949 __kfree_skb(skb); 1950 msk->bytes_consumed += count; 1951 } 1952 1953 if (copied >= len) 1954 break; 1955 } 1956 1957 return copied; 1958 } 1959 1960 /* receive buffer autotuning. See tcp_rcv_space_adjust for more information. 1961 * 1962 * Only difference: Use highest rtt estimate of the subflows in use. 1963 */ 1964 static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied) 1965 { 1966 struct mptcp_subflow_context *subflow; 1967 struct sock *sk = (struct sock *)msk; 1968 u8 scaling_ratio = U8_MAX; 1969 u32 time, advmss = 1; 1970 u64 rtt_us, mstamp; 1971 1972 msk_owned_by_me(msk); 1973 1974 if (copied <= 0) 1975 return; 1976 1977 msk->rcvq_space.copied += copied; 1978 1979 mstamp = div_u64(tcp_clock_ns(), NSEC_PER_USEC); 1980 time = tcp_stamp_us_delta(mstamp, msk->rcvq_space.time); 1981 1982 rtt_us = msk->rcvq_space.rtt_us; 1983 if (rtt_us && time < (rtt_us >> 3)) 1984 return; 1985 1986 rtt_us = 0; 1987 mptcp_for_each_subflow(msk, subflow) { 1988 const struct tcp_sock *tp; 1989 u64 sf_rtt_us; 1990 u32 sf_advmss; 1991 1992 tp = tcp_sk(mptcp_subflow_tcp_sock(subflow)); 1993 1994 sf_rtt_us = READ_ONCE(tp->rcv_rtt_est.rtt_us); 1995 sf_advmss = READ_ONCE(tp->advmss); 1996 1997 rtt_us = max(sf_rtt_us, rtt_us); 1998 advmss = max(sf_advmss, advmss); 1999 scaling_ratio = min(tp->scaling_ratio, scaling_ratio); 2000 } 2001 2002 msk->rcvq_space.rtt_us = rtt_us; 2003 msk->scaling_ratio = scaling_ratio; 2004 if (time < (rtt_us >> 3) || rtt_us == 0) 2005 return; 2006 2007 if (msk->rcvq_space.copied <= msk->rcvq_space.space) 2008 goto new_measure; 2009 2010 if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && 2011 !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { 2012 u64 rcvwin, grow; 2013 int rcvbuf; 2014 2015 rcvwin = ((u64)msk->rcvq_space.copied << 1) + 16 * advmss; 2016 2017 grow = rcvwin * (msk->rcvq_space.copied - msk->rcvq_space.space); 2018 2019 do_div(grow, msk->rcvq_space.space); 2020 rcvwin += (grow << 1); 2021 2022 rcvbuf = min_t(u64, __tcp_space_from_win(scaling_ratio, rcvwin), 2023 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2])); 2024 2025 if (rcvbuf > sk->sk_rcvbuf) { 2026 u32 window_clamp; 2027 2028 window_clamp = __tcp_win_from_space(scaling_ratio, rcvbuf); 2029 WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); 2030 2031 /* Make subflows follow along. If we do not do this, we 2032 * get drops at subflow level if skbs can't be moved to 2033 * the mptcp rx queue fast enough (announced rcv_win can 2034 * exceed ssk->sk_rcvbuf). 2035 */ 2036 mptcp_for_each_subflow(msk, subflow) { 2037 struct sock *ssk; 2038 bool slow; 2039 2040 ssk = mptcp_subflow_tcp_sock(subflow); 2041 slow = lock_sock_fast(ssk); 2042 WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf); 2043 tcp_sk(ssk)->window_clamp = window_clamp; 2044 tcp_cleanup_rbuf(ssk, 1); 2045 unlock_sock_fast(ssk, slow); 2046 } 2047 } 2048 } 2049 2050 msk->rcvq_space.space = msk->rcvq_space.copied; 2051 new_measure: 2052 msk->rcvq_space.copied = 0; 2053 msk->rcvq_space.time = mstamp; 2054 } 2055 2056 static void __mptcp_update_rmem(struct sock *sk) 2057 { 2058 struct mptcp_sock *msk = mptcp_sk(sk); 2059 2060 if (!msk->rmem_released) 2061 return; 2062 2063 atomic_sub(msk->rmem_released, &sk->sk_rmem_alloc); 2064 mptcp_rmem_uncharge(sk, msk->rmem_released); 2065 WRITE_ONCE(msk->rmem_released, 0); 2066 } 2067 2068 static void __mptcp_splice_receive_queue(struct sock *sk) 2069 { 2070 struct mptcp_sock *msk = mptcp_sk(sk); 2071 2072 skb_queue_splice_tail_init(&sk->sk_receive_queue, &msk->receive_queue); 2073 } 2074 2075 static bool __mptcp_move_skbs(struct mptcp_sock *msk) 2076 { 2077 struct sock *sk = (struct sock *)msk; 2078 unsigned int moved = 0; 2079 bool ret, done; 2080 2081 do { 2082 struct sock *ssk = mptcp_subflow_recv_lookup(msk); 2083 bool slowpath; 2084 2085 /* we can have data pending in the subflows only if the msk 2086 * receive buffer was full at subflow_data_ready() time, 2087 * that is an unlikely slow path. 2088 */ 2089 if (likely(!ssk)) 2090 break; 2091 2092 slowpath = lock_sock_fast(ssk); 2093 mptcp_data_lock(sk); 2094 __mptcp_update_rmem(sk); 2095 done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved); 2096 mptcp_data_unlock(sk); 2097 2098 if (unlikely(ssk->sk_err)) 2099 __mptcp_error_report(sk); 2100 unlock_sock_fast(ssk, slowpath); 2101 } while (!done); 2102 2103 /* acquire the data lock only if some input data is pending */ 2104 ret = moved > 0; 2105 if (!RB_EMPTY_ROOT(&msk->out_of_order_queue) || 2106 !skb_queue_empty_lockless(&sk->sk_receive_queue)) { 2107 mptcp_data_lock(sk); 2108 __mptcp_update_rmem(sk); 2109 ret |= __mptcp_ofo_queue(msk); 2110 __mptcp_splice_receive_queue(sk); 2111 mptcp_data_unlock(sk); 2112 } 2113 if (ret) 2114 mptcp_check_data_fin((struct sock *)msk); 2115 return !skb_queue_empty(&msk->receive_queue); 2116 } 2117 2118 static unsigned int mptcp_inq_hint(const struct sock *sk) 2119 { 2120 const struct mptcp_sock *msk = mptcp_sk(sk); 2121 const struct sk_buff *skb; 2122 2123 skb = skb_peek(&msk->receive_queue); 2124 if (skb) { 2125 u64 hint_val = msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; 2126 2127 if (hint_val >= INT_MAX) 2128 return INT_MAX; 2129 2130 return (unsigned int)hint_val; 2131 } 2132 2133 if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN)) 2134 return 1; 2135 2136 return 0; 2137 } 2138 2139 static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 2140 int flags, int *addr_len) 2141 { 2142 struct mptcp_sock *msk = mptcp_sk(sk); 2143 struct scm_timestamping_internal tss; 2144 int copied = 0, cmsg_flags = 0; 2145 int target; 2146 long timeo; 2147 2148 /* MSG_ERRQUEUE is really a no-op till we support IP_RECVERR */ 2149 if (unlikely(flags & MSG_ERRQUEUE)) 2150 return inet_recv_error(sk, msg, len, addr_len); 2151 2152 lock_sock(sk); 2153 if (unlikely(sk->sk_state == TCP_LISTEN)) { 2154 copied = -ENOTCONN; 2155 goto out_err; 2156 } 2157 2158 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 2159 2160 len = min_t(size_t, len, INT_MAX); 2161 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 2162 2163 if (unlikely(msk->recvmsg_inq)) 2164 cmsg_flags = MPTCP_CMSG_INQ; 2165 2166 while (copied < len) { 2167 int bytes_read; 2168 2169 bytes_read = __mptcp_recvmsg_mskq(msk, msg, len - copied, flags, &tss, &cmsg_flags); 2170 if (unlikely(bytes_read < 0)) { 2171 if (!copied) 2172 copied = bytes_read; 2173 goto out_err; 2174 } 2175 2176 copied += bytes_read; 2177 2178 /* be sure to advertise window change */ 2179 mptcp_cleanup_rbuf(msk); 2180 2181 if (skb_queue_empty(&msk->receive_queue) && __mptcp_move_skbs(msk)) 2182 continue; 2183 2184 /* only the master socket status is relevant here. The exit 2185 * conditions mirror closely tcp_recvmsg() 2186 */ 2187 if (copied >= target) 2188 break; 2189 2190 if (copied) { 2191 if (sk->sk_err || 2192 sk->sk_state == TCP_CLOSE || 2193 (sk->sk_shutdown & RCV_SHUTDOWN) || 2194 !timeo || 2195 signal_pending(current)) 2196 break; 2197 } else { 2198 if (sk->sk_err) { 2199 copied = sock_error(sk); 2200 break; 2201 } 2202 2203 if (sk->sk_shutdown & RCV_SHUTDOWN) { 2204 /* race breaker: the shutdown could be after the 2205 * previous receive queue check 2206 */ 2207 if (__mptcp_move_skbs(msk)) 2208 continue; 2209 break; 2210 } 2211 2212 if (sk->sk_state == TCP_CLOSE) { 2213 copied = -ENOTCONN; 2214 break; 2215 } 2216 2217 if (!timeo) { 2218 copied = -EAGAIN; 2219 break; 2220 } 2221 2222 if (signal_pending(current)) { 2223 copied = sock_intr_errno(timeo); 2224 break; 2225 } 2226 } 2227 2228 pr_debug("block timeout %ld", timeo); 2229 sk_wait_data(sk, &timeo, NULL); 2230 } 2231 2232 out_err: 2233 if (cmsg_flags && copied >= 0) { 2234 if (cmsg_flags & MPTCP_CMSG_TS) 2235 tcp_recv_timestamp(msg, sk, &tss); 2236 2237 if (cmsg_flags & MPTCP_CMSG_INQ) { 2238 unsigned int inq = mptcp_inq_hint(sk); 2239 2240 put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq); 2241 } 2242 } 2243 2244 pr_debug("msk=%p rx queue empty=%d:%d copied=%d", 2245 msk, skb_queue_empty_lockless(&sk->sk_receive_queue), 2246 skb_queue_empty(&msk->receive_queue), copied); 2247 if (!(flags & MSG_PEEK)) 2248 mptcp_rcv_space_adjust(msk, copied); 2249 2250 release_sock(sk); 2251 return copied; 2252 } 2253 2254 static void mptcp_retransmit_timer(struct timer_list *t) 2255 { 2256 struct inet_connection_sock *icsk = from_timer(icsk, t, 2257 icsk_retransmit_timer); 2258 struct sock *sk = &icsk->icsk_inet.sk; 2259 struct mptcp_sock *msk = mptcp_sk(sk); 2260 2261 bh_lock_sock(sk); 2262 if (!sock_owned_by_user(sk)) { 2263 /* we need a process context to retransmit */ 2264 if (!test_and_set_bit(MPTCP_WORK_RTX, &msk->flags)) 2265 mptcp_schedule_work(sk); 2266 } else { 2267 /* delegate our work to tcp_release_cb() */ 2268 __set_bit(MPTCP_RETRANSMIT, &msk->cb_flags); 2269 } 2270 bh_unlock_sock(sk); 2271 sock_put(sk); 2272 } 2273 2274 static void mptcp_tout_timer(struct timer_list *t) 2275 { 2276 struct sock *sk = from_timer(sk, t, sk_timer); 2277 2278 mptcp_schedule_work(sk); 2279 sock_put(sk); 2280 } 2281 2282 /* Find an idle subflow. Return NULL if there is unacked data at tcp 2283 * level. 2284 * 2285 * A backup subflow is returned only if that is the only kind available. 2286 */ 2287 struct sock *mptcp_subflow_get_retrans(struct mptcp_sock *msk) 2288 { 2289 struct sock *backup = NULL, *pick = NULL; 2290 struct mptcp_subflow_context *subflow; 2291 int min_stale_count = INT_MAX; 2292 2293 mptcp_for_each_subflow(msk, subflow) { 2294 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2295 2296 if (!__mptcp_subflow_active(subflow)) 2297 continue; 2298 2299 /* still data outstanding at TCP level? skip this */ 2300 if (!tcp_rtx_and_write_queues_empty(ssk)) { 2301 mptcp_pm_subflow_chk_stale(msk, ssk); 2302 min_stale_count = min_t(int, min_stale_count, subflow->stale_count); 2303 continue; 2304 } 2305 2306 if (subflow->backup) { 2307 if (!backup) 2308 backup = ssk; 2309 continue; 2310 } 2311 2312 if (!pick) 2313 pick = ssk; 2314 } 2315 2316 if (pick) 2317 return pick; 2318 2319 /* use backup only if there are no progresses anywhere */ 2320 return min_stale_count > 1 ? backup : NULL; 2321 } 2322 2323 bool __mptcp_retransmit_pending_data(struct sock *sk) 2324 { 2325 struct mptcp_data_frag *cur, *rtx_head; 2326 struct mptcp_sock *msk = mptcp_sk(sk); 2327 2328 if (__mptcp_check_fallback(msk)) 2329 return false; 2330 2331 if (tcp_rtx_and_write_queues_empty(sk)) 2332 return false; 2333 2334 /* the closing socket has some data untransmitted and/or unacked: 2335 * some data in the mptcp rtx queue has not really xmitted yet. 2336 * keep it simple and re-inject the whole mptcp level rtx queue 2337 */ 2338 mptcp_data_lock(sk); 2339 __mptcp_clean_una_wakeup(sk); 2340 rtx_head = mptcp_rtx_head(sk); 2341 if (!rtx_head) { 2342 mptcp_data_unlock(sk); 2343 return false; 2344 } 2345 2346 msk->recovery_snd_nxt = msk->snd_nxt; 2347 msk->recovery = true; 2348 mptcp_data_unlock(sk); 2349 2350 msk->first_pending = rtx_head; 2351 msk->snd_burst = 0; 2352 2353 /* be sure to clear the "sent status" on all re-injected fragments */ 2354 list_for_each_entry(cur, &msk->rtx_queue, list) { 2355 if (!cur->already_sent) 2356 break; 2357 cur->already_sent = 0; 2358 } 2359 2360 return true; 2361 } 2362 2363 /* flags for __mptcp_close_ssk() */ 2364 #define MPTCP_CF_PUSH BIT(1) 2365 #define MPTCP_CF_FASTCLOSE BIT(2) 2366 2367 /* be sure to send a reset only if the caller asked for it, also 2368 * clean completely the subflow status when the subflow reaches 2369 * TCP_CLOSE state 2370 */ 2371 static void __mptcp_subflow_disconnect(struct sock *ssk, 2372 struct mptcp_subflow_context *subflow, 2373 unsigned int flags) 2374 { 2375 if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || 2376 (flags & MPTCP_CF_FASTCLOSE)) { 2377 /* The MPTCP code never wait on the subflow sockets, TCP-level 2378 * disconnect should never fail 2379 */ 2380 WARN_ON_ONCE(tcp_disconnect(ssk, 0)); 2381 mptcp_subflow_ctx_reset(subflow); 2382 } else { 2383 tcp_shutdown(ssk, SEND_SHUTDOWN); 2384 } 2385 } 2386 2387 /* subflow sockets can be either outgoing (connect) or incoming 2388 * (accept). 2389 * 2390 * Outgoing subflows use in-kernel sockets. 2391 * Incoming subflows do not have their own 'struct socket' allocated, 2392 * so we need to use tcp_close() after detaching them from the mptcp 2393 * parent socket. 2394 */ 2395 static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2396 struct mptcp_subflow_context *subflow, 2397 unsigned int flags) 2398 { 2399 struct mptcp_sock *msk = mptcp_sk(sk); 2400 bool dispose_it, need_push = false; 2401 2402 /* If the first subflow moved to a close state before accept, e.g. due 2403 * to an incoming reset or listener shutdown, the subflow socket is 2404 * already deleted by inet_child_forget() and the mptcp socket can't 2405 * survive too. 2406 */ 2407 if (msk->in_accept_queue && msk->first == ssk && 2408 (sock_flag(sk, SOCK_DEAD) || sock_flag(ssk, SOCK_DEAD))) { 2409 /* ensure later check in mptcp_worker() will dispose the msk */ 2410 sock_set_flag(sk, SOCK_DEAD); 2411 mptcp_set_close_tout(sk, tcp_jiffies32 - (mptcp_close_timeout(sk) + 1)); 2412 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2413 mptcp_subflow_drop_ctx(ssk); 2414 goto out_release; 2415 } 2416 2417 dispose_it = msk->free_first || ssk != msk->first; 2418 if (dispose_it) 2419 list_del(&subflow->node); 2420 2421 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 2422 2423 if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) { 2424 /* be sure to force the tcp_close path 2425 * to generate the egress reset 2426 */ 2427 ssk->sk_lingertime = 0; 2428 sock_set_flag(ssk, SOCK_LINGER); 2429 subflow->send_fastclose = 1; 2430 } 2431 2432 need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); 2433 if (!dispose_it) { 2434 __mptcp_subflow_disconnect(ssk, subflow, flags); 2435 release_sock(ssk); 2436 2437 goto out; 2438 } 2439 2440 subflow->disposable = 1; 2441 2442 /* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops 2443 * the ssk has been already destroyed, we just need to release the 2444 * reference owned by msk; 2445 */ 2446 if (!inet_csk(ssk)->icsk_ulp_ops) { 2447 WARN_ON_ONCE(!sock_flag(ssk, SOCK_DEAD)); 2448 kfree_rcu(subflow, rcu); 2449 } else { 2450 /* otherwise tcp will dispose of the ssk and subflow ctx */ 2451 __tcp_close(ssk, 0); 2452 2453 /* close acquired an extra ref */ 2454 __sock_put(ssk); 2455 } 2456 2457 out_release: 2458 __mptcp_subflow_error_report(sk, ssk); 2459 release_sock(ssk); 2460 2461 sock_put(ssk); 2462 2463 if (ssk == msk->first) 2464 WRITE_ONCE(msk->first, NULL); 2465 2466 out: 2467 __mptcp_sync_sndbuf(sk); 2468 if (need_push) 2469 __mptcp_push_pending(sk, 0); 2470 2471 /* Catch every 'all subflows closed' scenario, including peers silently 2472 * closing them, e.g. due to timeout. 2473 * For established sockets, allow an additional timeout before closing, 2474 * as the protocol can still create more subflows. 2475 */ 2476 if (list_is_singular(&msk->conn_list) && msk->first && 2477 inet_sk_state_load(msk->first) == TCP_CLOSE) { 2478 if (sk->sk_state != TCP_ESTABLISHED || 2479 msk->in_accept_queue || sock_flag(sk, SOCK_DEAD)) { 2480 inet_sk_state_store(sk, TCP_CLOSE); 2481 mptcp_close_wake_up(sk); 2482 } else { 2483 mptcp_start_tout_timer(sk); 2484 } 2485 } 2486 } 2487 2488 void mptcp_close_ssk(struct sock *sk, struct sock *ssk, 2489 struct mptcp_subflow_context *subflow) 2490 { 2491 if (sk->sk_state == TCP_ESTABLISHED) 2492 mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); 2493 2494 /* subflow aborted before reaching the fully_established status 2495 * attempt the creation of the next subflow 2496 */ 2497 mptcp_pm_subflow_check_next(mptcp_sk(sk), subflow); 2498 2499 __mptcp_close_ssk(sk, ssk, subflow, MPTCP_CF_PUSH); 2500 } 2501 2502 static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu) 2503 { 2504 return 0; 2505 } 2506 2507 static void __mptcp_close_subflow(struct sock *sk) 2508 { 2509 struct mptcp_subflow_context *subflow, *tmp; 2510 struct mptcp_sock *msk = mptcp_sk(sk); 2511 2512 might_sleep(); 2513 2514 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2515 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 2516 2517 if (inet_sk_state_load(ssk) != TCP_CLOSE) 2518 continue; 2519 2520 /* 'subflow_data_ready' will re-sched once rx queue is empty */ 2521 if (!skb_queue_empty_lockless(&ssk->sk_receive_queue)) 2522 continue; 2523 2524 mptcp_close_ssk(sk, ssk, subflow); 2525 } 2526 2527 } 2528 2529 static bool mptcp_close_tout_expired(const struct sock *sk) 2530 { 2531 if (!inet_csk(sk)->icsk_mtup.probe_timestamp || 2532 sk->sk_state == TCP_CLOSE) 2533 return false; 2534 2535 return time_after32(tcp_jiffies32, 2536 inet_csk(sk)->icsk_mtup.probe_timestamp + mptcp_close_timeout(sk)); 2537 } 2538 2539 static void mptcp_check_fastclose(struct mptcp_sock *msk) 2540 { 2541 struct mptcp_subflow_context *subflow, *tmp; 2542 struct sock *sk = (struct sock *)msk; 2543 2544 if (likely(!READ_ONCE(msk->rcv_fastclose))) 2545 return; 2546 2547 mptcp_token_destroy(msk); 2548 2549 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 2550 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2551 bool slow; 2552 2553 slow = lock_sock_fast(tcp_sk); 2554 if (tcp_sk->sk_state != TCP_CLOSE) { 2555 tcp_send_active_reset(tcp_sk, GFP_ATOMIC); 2556 tcp_set_state(tcp_sk, TCP_CLOSE); 2557 } 2558 unlock_sock_fast(tcp_sk, slow); 2559 } 2560 2561 /* Mirror the tcp_reset() error propagation */ 2562 switch (sk->sk_state) { 2563 case TCP_SYN_SENT: 2564 WRITE_ONCE(sk->sk_err, ECONNREFUSED); 2565 break; 2566 case TCP_CLOSE_WAIT: 2567 WRITE_ONCE(sk->sk_err, EPIPE); 2568 break; 2569 case TCP_CLOSE: 2570 return; 2571 default: 2572 WRITE_ONCE(sk->sk_err, ECONNRESET); 2573 } 2574 2575 inet_sk_state_store(sk, TCP_CLOSE); 2576 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); 2577 smp_mb__before_atomic(); /* SHUTDOWN must be visible first */ 2578 set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags); 2579 2580 /* the calling mptcp_worker will properly destroy the socket */ 2581 if (sock_flag(sk, SOCK_DEAD)) 2582 return; 2583 2584 sk->sk_state_change(sk); 2585 sk_error_report(sk); 2586 } 2587 2588 static void __mptcp_retrans(struct sock *sk) 2589 { 2590 struct mptcp_sock *msk = mptcp_sk(sk); 2591 struct mptcp_subflow_context *subflow; 2592 struct mptcp_sendmsg_info info = {}; 2593 struct mptcp_data_frag *dfrag; 2594 struct sock *ssk; 2595 int ret, err; 2596 u16 len = 0; 2597 2598 mptcp_clean_una_wakeup(sk); 2599 2600 /* first check ssk: need to kick "stale" logic */ 2601 err = mptcp_sched_get_retrans(msk); 2602 dfrag = mptcp_rtx_head(sk); 2603 if (!dfrag) { 2604 if (mptcp_data_fin_enabled(msk)) { 2605 struct inet_connection_sock *icsk = inet_csk(sk); 2606 2607 icsk->icsk_retransmits++; 2608 mptcp_set_datafin_timeout(sk); 2609 mptcp_send_ack(msk); 2610 2611 goto reset_timer; 2612 } 2613 2614 if (!mptcp_send_head(sk)) 2615 return; 2616 2617 goto reset_timer; 2618 } 2619 2620 if (err) 2621 goto reset_timer; 2622 2623 mptcp_for_each_subflow(msk, subflow) { 2624 if (READ_ONCE(subflow->scheduled)) { 2625 u16 copied = 0; 2626 2627 mptcp_subflow_set_scheduled(subflow, false); 2628 2629 ssk = mptcp_subflow_tcp_sock(subflow); 2630 2631 lock_sock(ssk); 2632 2633 /* limit retransmission to the bytes already sent on some subflows */ 2634 info.sent = 0; 2635 info.limit = READ_ONCE(msk->csum_enabled) ? dfrag->data_len : 2636 dfrag->already_sent; 2637 while (info.sent < info.limit) { 2638 ret = mptcp_sendmsg_frag(sk, ssk, dfrag, &info); 2639 if (ret <= 0) 2640 break; 2641 2642 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RETRANSSEGS); 2643 copied += ret; 2644 info.sent += ret; 2645 } 2646 if (copied) { 2647 len = max(copied, len); 2648 tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, 2649 info.size_goal); 2650 WRITE_ONCE(msk->allow_infinite_fallback, false); 2651 } 2652 2653 release_sock(ssk); 2654 } 2655 } 2656 2657 msk->bytes_retrans += len; 2658 dfrag->already_sent = max(dfrag->already_sent, len); 2659 2660 reset_timer: 2661 mptcp_check_and_set_pending(sk); 2662 2663 if (!mptcp_rtx_timer_pending(sk)) 2664 mptcp_reset_rtx_timer(sk); 2665 } 2666 2667 /* schedule the timeout timer for the relevant event: either close timeout 2668 * or mp_fail timeout. The close timeout takes precedence on the mp_fail one 2669 */ 2670 void mptcp_reset_tout_timer(struct mptcp_sock *msk, unsigned long fail_tout) 2671 { 2672 struct sock *sk = (struct sock *)msk; 2673 unsigned long timeout, close_timeout; 2674 2675 if (!fail_tout && !inet_csk(sk)->icsk_mtup.probe_timestamp) 2676 return; 2677 2678 close_timeout = inet_csk(sk)->icsk_mtup.probe_timestamp - tcp_jiffies32 + jiffies + 2679 mptcp_close_timeout(sk); 2680 2681 /* the close timeout takes precedence on the fail one, and here at least one of 2682 * them is active 2683 */ 2684 timeout = inet_csk(sk)->icsk_mtup.probe_timestamp ? close_timeout : fail_tout; 2685 2686 sk_reset_timer(sk, &sk->sk_timer, timeout); 2687 } 2688 2689 static void mptcp_mp_fail_no_response(struct mptcp_sock *msk) 2690 { 2691 struct sock *ssk = msk->first; 2692 bool slow; 2693 2694 if (!ssk) 2695 return; 2696 2697 pr_debug("MP_FAIL doesn't respond, reset the subflow"); 2698 2699 slow = lock_sock_fast(ssk); 2700 mptcp_subflow_reset(ssk); 2701 WRITE_ONCE(mptcp_subflow_ctx(ssk)->fail_tout, 0); 2702 unlock_sock_fast(ssk, slow); 2703 } 2704 2705 static void mptcp_do_fastclose(struct sock *sk) 2706 { 2707 struct mptcp_subflow_context *subflow, *tmp; 2708 struct mptcp_sock *msk = mptcp_sk(sk); 2709 2710 inet_sk_state_store(sk, TCP_CLOSE); 2711 mptcp_for_each_subflow_safe(msk, subflow, tmp) 2712 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), 2713 subflow, MPTCP_CF_FASTCLOSE); 2714 } 2715 2716 static void mptcp_worker(struct work_struct *work) 2717 { 2718 struct mptcp_sock *msk = container_of(work, struct mptcp_sock, work); 2719 struct sock *sk = (struct sock *)msk; 2720 unsigned long fail_tout; 2721 int state; 2722 2723 lock_sock(sk); 2724 state = sk->sk_state; 2725 if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN))) 2726 goto unlock; 2727 2728 mptcp_check_fastclose(msk); 2729 2730 mptcp_pm_nl_work(msk); 2731 2732 mptcp_check_send_data_fin(sk); 2733 mptcp_check_data_fin_ack(sk); 2734 mptcp_check_data_fin(sk); 2735 2736 if (test_and_clear_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) 2737 __mptcp_close_subflow(sk); 2738 2739 if (mptcp_close_tout_expired(sk)) { 2740 mptcp_do_fastclose(sk); 2741 mptcp_close_wake_up(sk); 2742 } 2743 2744 if (sock_flag(sk, SOCK_DEAD) && sk->sk_state == TCP_CLOSE) { 2745 __mptcp_destroy_sock(sk); 2746 goto unlock; 2747 } 2748 2749 if (test_and_clear_bit(MPTCP_WORK_RTX, &msk->flags)) 2750 __mptcp_retrans(sk); 2751 2752 fail_tout = msk->first ? READ_ONCE(mptcp_subflow_ctx(msk->first)->fail_tout) : 0; 2753 if (fail_tout && time_after(jiffies, fail_tout)) 2754 mptcp_mp_fail_no_response(msk); 2755 2756 unlock: 2757 release_sock(sk); 2758 sock_put(sk); 2759 } 2760 2761 static void __mptcp_init_sock(struct sock *sk) 2762 { 2763 struct mptcp_sock *msk = mptcp_sk(sk); 2764 2765 INIT_LIST_HEAD(&msk->conn_list); 2766 INIT_LIST_HEAD(&msk->join_list); 2767 INIT_LIST_HEAD(&msk->rtx_queue); 2768 INIT_WORK(&msk->work, mptcp_worker); 2769 __skb_queue_head_init(&msk->receive_queue); 2770 msk->out_of_order_queue = RB_ROOT; 2771 msk->first_pending = NULL; 2772 msk->rmem_fwd_alloc = 0; 2773 WRITE_ONCE(msk->rmem_released, 0); 2774 msk->timer_ival = TCP_RTO_MIN; 2775 msk->scaling_ratio = TCP_DEFAULT_SCALING_RATIO; 2776 2777 WRITE_ONCE(msk->first, NULL); 2778 inet_csk(sk)->icsk_sync_mss = mptcp_sync_mss; 2779 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 2780 WRITE_ONCE(msk->allow_infinite_fallback, true); 2781 msk->recovery = false; 2782 msk->subflow_id = 1; 2783 2784 mptcp_pm_data_init(msk); 2785 2786 /* re-use the csk retrans timer for MPTCP-level retrans */ 2787 timer_setup(&msk->sk.icsk_retransmit_timer, mptcp_retransmit_timer, 0); 2788 timer_setup(&sk->sk_timer, mptcp_tout_timer, 0); 2789 } 2790 2791 static void mptcp_ca_reset(struct sock *sk) 2792 { 2793 struct inet_connection_sock *icsk = inet_csk(sk); 2794 2795 tcp_assign_congestion_control(sk); 2796 strcpy(mptcp_sk(sk)->ca_name, icsk->icsk_ca_ops->name); 2797 2798 /* no need to keep a reference to the ops, the name will suffice */ 2799 tcp_cleanup_congestion_control(sk); 2800 icsk->icsk_ca_ops = NULL; 2801 } 2802 2803 static int mptcp_init_sock(struct sock *sk) 2804 { 2805 struct net *net = sock_net(sk); 2806 int ret; 2807 2808 __mptcp_init_sock(sk); 2809 2810 if (!mptcp_is_enabled(net)) 2811 return -ENOPROTOOPT; 2812 2813 if (unlikely(!net->mib.mptcp_statistics) && !mptcp_mib_alloc(net)) 2814 return -ENOMEM; 2815 2816 ret = mptcp_init_sched(mptcp_sk(sk), 2817 mptcp_sched_find(mptcp_get_scheduler(net))); 2818 if (ret) 2819 return ret; 2820 2821 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags); 2822 2823 /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will 2824 * propagate the correct value 2825 */ 2826 mptcp_ca_reset(sk); 2827 2828 sk_sockets_allocated_inc(sk); 2829 sk->sk_rcvbuf = READ_ONCE(net->ipv4.sysctl_tcp_rmem[1]); 2830 sk->sk_sndbuf = READ_ONCE(net->ipv4.sysctl_tcp_wmem[1]); 2831 2832 return 0; 2833 } 2834 2835 static void __mptcp_clear_xmit(struct sock *sk) 2836 { 2837 struct mptcp_sock *msk = mptcp_sk(sk); 2838 struct mptcp_data_frag *dtmp, *dfrag; 2839 2840 WRITE_ONCE(msk->first_pending, NULL); 2841 list_for_each_entry_safe(dfrag, dtmp, &msk->rtx_queue, list) 2842 dfrag_clear(sk, dfrag); 2843 } 2844 2845 void mptcp_cancel_work(struct sock *sk) 2846 { 2847 struct mptcp_sock *msk = mptcp_sk(sk); 2848 2849 if (cancel_work_sync(&msk->work)) 2850 __sock_put(sk); 2851 } 2852 2853 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) 2854 { 2855 lock_sock(ssk); 2856 2857 switch (ssk->sk_state) { 2858 case TCP_LISTEN: 2859 if (!(how & RCV_SHUTDOWN)) 2860 break; 2861 fallthrough; 2862 case TCP_SYN_SENT: 2863 WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK)); 2864 break; 2865 default: 2866 if (__mptcp_check_fallback(mptcp_sk(sk))) { 2867 pr_debug("Fallback"); 2868 ssk->sk_shutdown |= how; 2869 tcp_shutdown(ssk, how); 2870 2871 /* simulate the data_fin ack reception to let the state 2872 * machine move forward 2873 */ 2874 WRITE_ONCE(mptcp_sk(sk)->snd_una, mptcp_sk(sk)->snd_nxt); 2875 mptcp_schedule_work(sk); 2876 } else { 2877 pr_debug("Sending DATA_FIN on subflow %p", ssk); 2878 tcp_send_ack(ssk); 2879 if (!mptcp_rtx_timer_pending(sk)) 2880 mptcp_reset_rtx_timer(sk); 2881 } 2882 break; 2883 } 2884 2885 release_sock(ssk); 2886 } 2887 2888 static const unsigned char new_state[16] = { 2889 /* current state: new state: action: */ 2890 [0 /* (Invalid) */] = TCP_CLOSE, 2891 [TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2892 [TCP_SYN_SENT] = TCP_CLOSE, 2893 [TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN, 2894 [TCP_FIN_WAIT1] = TCP_FIN_WAIT1, 2895 [TCP_FIN_WAIT2] = TCP_FIN_WAIT2, 2896 [TCP_TIME_WAIT] = TCP_CLOSE, /* should not happen ! */ 2897 [TCP_CLOSE] = TCP_CLOSE, 2898 [TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN, 2899 [TCP_LAST_ACK] = TCP_LAST_ACK, 2900 [TCP_LISTEN] = TCP_CLOSE, 2901 [TCP_CLOSING] = TCP_CLOSING, 2902 [TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */ 2903 }; 2904 2905 static int mptcp_close_state(struct sock *sk) 2906 { 2907 int next = (int)new_state[sk->sk_state]; 2908 int ns = next & TCP_STATE_MASK; 2909 2910 inet_sk_state_store(sk, ns); 2911 2912 return next & TCP_ACTION_FIN; 2913 } 2914 2915 static void mptcp_check_send_data_fin(struct sock *sk) 2916 { 2917 struct mptcp_subflow_context *subflow; 2918 struct mptcp_sock *msk = mptcp_sk(sk); 2919 2920 pr_debug("msk=%p snd_data_fin_enable=%d pending=%d snd_nxt=%llu write_seq=%llu", 2921 msk, msk->snd_data_fin_enable, !!mptcp_send_head(sk), 2922 msk->snd_nxt, msk->write_seq); 2923 2924 /* we still need to enqueue subflows or not really shutting down, 2925 * skip this 2926 */ 2927 if (!msk->snd_data_fin_enable || msk->snd_nxt + 1 != msk->write_seq || 2928 mptcp_send_head(sk)) 2929 return; 2930 2931 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 2932 2933 mptcp_for_each_subflow(msk, subflow) { 2934 struct sock *tcp_sk = mptcp_subflow_tcp_sock(subflow); 2935 2936 mptcp_subflow_shutdown(sk, tcp_sk, SEND_SHUTDOWN); 2937 } 2938 } 2939 2940 static void __mptcp_wr_shutdown(struct sock *sk) 2941 { 2942 struct mptcp_sock *msk = mptcp_sk(sk); 2943 2944 pr_debug("msk=%p snd_data_fin_enable=%d shutdown=%x state=%d pending=%d", 2945 msk, msk->snd_data_fin_enable, sk->sk_shutdown, sk->sk_state, 2946 !!mptcp_send_head(sk)); 2947 2948 /* will be ignored by fallback sockets */ 2949 WRITE_ONCE(msk->write_seq, msk->write_seq + 1); 2950 WRITE_ONCE(msk->snd_data_fin_enable, 1); 2951 2952 mptcp_check_send_data_fin(sk); 2953 } 2954 2955 static void __mptcp_destroy_sock(struct sock *sk) 2956 { 2957 struct mptcp_sock *msk = mptcp_sk(sk); 2958 2959 pr_debug("msk=%p", msk); 2960 2961 might_sleep(); 2962 2963 mptcp_stop_rtx_timer(sk); 2964 sk_stop_timer(sk, &sk->sk_timer); 2965 msk->pm.status = 0; 2966 mptcp_release_sched(msk); 2967 2968 sk->sk_prot->destroy(sk); 2969 2970 WARN_ON_ONCE(msk->rmem_fwd_alloc); 2971 WARN_ON_ONCE(msk->rmem_released); 2972 sk_stream_kill_queues(sk); 2973 xfrm_sk_free_policy(sk); 2974 2975 sock_put(sk); 2976 } 2977 2978 void __mptcp_unaccepted_force_close(struct sock *sk) 2979 { 2980 sock_set_flag(sk, SOCK_DEAD); 2981 mptcp_do_fastclose(sk); 2982 __mptcp_destroy_sock(sk); 2983 } 2984 2985 static __poll_t mptcp_check_readable(struct sock *sk) 2986 { 2987 return mptcp_epollin_ready(sk) ? EPOLLIN | EPOLLRDNORM : 0; 2988 } 2989 2990 static void mptcp_check_listen_stop(struct sock *sk) 2991 { 2992 struct sock *ssk; 2993 2994 if (inet_sk_state_load(sk) != TCP_LISTEN) 2995 return; 2996 2997 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); 2998 ssk = mptcp_sk(sk)->first; 2999 if (WARN_ON_ONCE(!ssk || inet_sk_state_load(ssk) != TCP_LISTEN)) 3000 return; 3001 3002 lock_sock_nested(ssk, SINGLE_DEPTH_NESTING); 3003 tcp_set_state(ssk, TCP_CLOSE); 3004 mptcp_subflow_queue_clean(sk, ssk); 3005 inet_csk_listen_stop(ssk); 3006 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CLOSED); 3007 release_sock(ssk); 3008 } 3009 3010 bool __mptcp_close(struct sock *sk, long timeout) 3011 { 3012 struct mptcp_subflow_context *subflow; 3013 struct mptcp_sock *msk = mptcp_sk(sk); 3014 bool do_cancel_work = false; 3015 int subflows_alive = 0; 3016 3017 WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK); 3018 3019 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) { 3020 mptcp_check_listen_stop(sk); 3021 inet_sk_state_store(sk, TCP_CLOSE); 3022 goto cleanup; 3023 } 3024 3025 if (mptcp_data_avail(msk) || timeout < 0) { 3026 /* If the msk has read data, or the caller explicitly ask it, 3027 * do the MPTCP equivalent of TCP reset, aka MPTCP fastclose 3028 */ 3029 mptcp_do_fastclose(sk); 3030 timeout = 0; 3031 } else if (mptcp_close_state(sk)) { 3032 __mptcp_wr_shutdown(sk); 3033 } 3034 3035 sk_stream_wait_close(sk, timeout); 3036 3037 cleanup: 3038 /* orphan all the subflows */ 3039 mptcp_for_each_subflow(msk, subflow) { 3040 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3041 bool slow = lock_sock_fast_nested(ssk); 3042 3043 subflows_alive += ssk->sk_state != TCP_CLOSE; 3044 3045 /* since the close timeout takes precedence on the fail one, 3046 * cancel the latter 3047 */ 3048 if (ssk == msk->first) 3049 subflow->fail_tout = 0; 3050 3051 /* detach from the parent socket, but allow data_ready to 3052 * push incoming data into the mptcp stack, to properly ack it 3053 */ 3054 ssk->sk_socket = NULL; 3055 ssk->sk_wq = NULL; 3056 unlock_sock_fast(ssk, slow); 3057 } 3058 sock_orphan(sk); 3059 3060 /* all the subflows are closed, only timeout can change the msk 3061 * state, let's not keep resources busy for no reasons 3062 */ 3063 if (subflows_alive == 0) 3064 inet_sk_state_store(sk, TCP_CLOSE); 3065 3066 sock_hold(sk); 3067 pr_debug("msk=%p state=%d", sk, sk->sk_state); 3068 if (msk->token) 3069 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 3070 3071 if (sk->sk_state == TCP_CLOSE) { 3072 __mptcp_destroy_sock(sk); 3073 do_cancel_work = true; 3074 } else { 3075 mptcp_start_tout_timer(sk); 3076 } 3077 3078 return do_cancel_work; 3079 } 3080 3081 static void mptcp_close(struct sock *sk, long timeout) 3082 { 3083 bool do_cancel_work; 3084 3085 lock_sock(sk); 3086 3087 do_cancel_work = __mptcp_close(sk, timeout); 3088 release_sock(sk); 3089 if (do_cancel_work) 3090 mptcp_cancel_work(sk); 3091 3092 sock_put(sk); 3093 } 3094 3095 static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) 3096 { 3097 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3098 const struct ipv6_pinfo *ssk6 = inet6_sk(ssk); 3099 struct ipv6_pinfo *msk6 = inet6_sk(msk); 3100 3101 msk->sk_v6_daddr = ssk->sk_v6_daddr; 3102 msk->sk_v6_rcv_saddr = ssk->sk_v6_rcv_saddr; 3103 3104 if (msk6 && ssk6) { 3105 msk6->saddr = ssk6->saddr; 3106 msk6->flow_label = ssk6->flow_label; 3107 } 3108 #endif 3109 3110 inet_sk(msk)->inet_num = inet_sk(ssk)->inet_num; 3111 inet_sk(msk)->inet_dport = inet_sk(ssk)->inet_dport; 3112 inet_sk(msk)->inet_sport = inet_sk(ssk)->inet_sport; 3113 inet_sk(msk)->inet_daddr = inet_sk(ssk)->inet_daddr; 3114 inet_sk(msk)->inet_saddr = inet_sk(ssk)->inet_saddr; 3115 inet_sk(msk)->inet_rcv_saddr = inet_sk(ssk)->inet_rcv_saddr; 3116 } 3117 3118 static int mptcp_disconnect(struct sock *sk, int flags) 3119 { 3120 struct mptcp_sock *msk = mptcp_sk(sk); 3121 3122 /* We are on the fastopen error path. We can't call straight into the 3123 * subflows cleanup code due to lock nesting (we are already under 3124 * msk->firstsocket lock). 3125 */ 3126 if (msk->fastopening) 3127 return -EBUSY; 3128 3129 mptcp_check_listen_stop(sk); 3130 inet_sk_state_store(sk, TCP_CLOSE); 3131 3132 mptcp_stop_rtx_timer(sk); 3133 mptcp_stop_tout_timer(sk); 3134 3135 if (msk->token) 3136 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 3137 3138 /* msk->subflow is still intact, the following will not free the first 3139 * subflow 3140 */ 3141 mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); 3142 WRITE_ONCE(msk->flags, 0); 3143 msk->cb_flags = 0; 3144 msk->push_pending = 0; 3145 msk->recovery = false; 3146 msk->can_ack = false; 3147 msk->fully_established = false; 3148 msk->rcv_data_fin = false; 3149 msk->snd_data_fin_enable = false; 3150 msk->rcv_fastclose = false; 3151 msk->use_64bit_ack = false; 3152 msk->bytes_consumed = 0; 3153 WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); 3154 mptcp_pm_data_reset(msk); 3155 mptcp_ca_reset(sk); 3156 msk->bytes_acked = 0; 3157 msk->bytes_received = 0; 3158 msk->bytes_sent = 0; 3159 msk->bytes_retrans = 0; 3160 3161 WRITE_ONCE(sk->sk_shutdown, 0); 3162 sk_error_report(sk); 3163 return 0; 3164 } 3165 3166 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3167 static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk) 3168 { 3169 unsigned int offset = sizeof(struct mptcp6_sock) - sizeof(struct ipv6_pinfo); 3170 3171 return (struct ipv6_pinfo *)(((u8 *)sk) + offset); 3172 } 3173 #endif 3174 3175 struct sock *mptcp_sk_clone_init(const struct sock *sk, 3176 const struct mptcp_options_received *mp_opt, 3177 struct sock *ssk, 3178 struct request_sock *req) 3179 { 3180 struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); 3181 struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC); 3182 struct mptcp_sock *msk; 3183 3184 if (!nsk) 3185 return NULL; 3186 3187 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3188 if (nsk->sk_family == AF_INET6) 3189 inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk); 3190 #endif 3191 3192 __mptcp_init_sock(nsk); 3193 3194 msk = mptcp_sk(nsk); 3195 msk->local_key = subflow_req->local_key; 3196 msk->token = subflow_req->token; 3197 msk->in_accept_queue = 1; 3198 WRITE_ONCE(msk->fully_established, false); 3199 if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD) 3200 WRITE_ONCE(msk->csum_enabled, true); 3201 3202 msk->write_seq = subflow_req->idsn + 1; 3203 msk->snd_nxt = msk->write_seq; 3204 msk->snd_una = msk->write_seq; 3205 msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd; 3206 msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq; 3207 mptcp_init_sched(msk, mptcp_sk(sk)->sched); 3208 3209 /* passive msk is created after the first/MPC subflow */ 3210 msk->subflow_id = 2; 3211 3212 sock_reset_flag(nsk, SOCK_RCU_FREE); 3213 security_inet_csk_clone(nsk, req); 3214 3215 /* this can't race with mptcp_close(), as the msk is 3216 * not yet exposted to user-space 3217 */ 3218 inet_sk_state_store(nsk, TCP_ESTABLISHED); 3219 3220 /* The msk maintain a ref to each subflow in the connections list */ 3221 WRITE_ONCE(msk->first, ssk); 3222 list_add(&mptcp_subflow_ctx(ssk)->node, &msk->conn_list); 3223 sock_hold(ssk); 3224 3225 /* new mpc subflow takes ownership of the newly 3226 * created mptcp socket 3227 */ 3228 mptcp_token_accept(subflow_req, msk); 3229 3230 /* set msk addresses early to ensure mptcp_pm_get_local_id() 3231 * uses the correct data 3232 */ 3233 mptcp_copy_inaddrs(nsk, ssk); 3234 __mptcp_propagate_sndbuf(nsk, ssk); 3235 3236 mptcp_rcv_space_init(msk, ssk); 3237 bh_unlock_sock(nsk); 3238 3239 /* note: the newly allocated socket refcount is 2 now */ 3240 return nsk; 3241 } 3242 3243 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk) 3244 { 3245 const struct tcp_sock *tp = tcp_sk(ssk); 3246 3247 msk->rcvq_space.copied = 0; 3248 msk->rcvq_space.rtt_us = 0; 3249 3250 msk->rcvq_space.time = tp->tcp_mstamp; 3251 3252 /* initial rcv_space offering made to peer */ 3253 msk->rcvq_space.space = min_t(u32, tp->rcv_wnd, 3254 TCP_INIT_CWND * tp->advmss); 3255 if (msk->rcvq_space.space == 0) 3256 msk->rcvq_space.space = TCP_INIT_CWND * TCP_MSS_DEFAULT; 3257 3258 WRITE_ONCE(msk->wnd_end, msk->snd_nxt + tcp_sk(ssk)->snd_wnd); 3259 } 3260 3261 static struct sock *mptcp_accept(struct sock *ssk, int flags, int *err, 3262 bool kern) 3263 { 3264 struct sock *newsk; 3265 3266 pr_debug("ssk=%p, listener=%p", ssk, mptcp_subflow_ctx(ssk)); 3267 newsk = inet_csk_accept(ssk, flags, err, kern); 3268 if (!newsk) 3269 return NULL; 3270 3271 pr_debug("newsk=%p, subflow is mptcp=%d", newsk, sk_is_mptcp(newsk)); 3272 if (sk_is_mptcp(newsk)) { 3273 struct mptcp_subflow_context *subflow; 3274 struct sock *new_mptcp_sock; 3275 3276 subflow = mptcp_subflow_ctx(newsk); 3277 new_mptcp_sock = subflow->conn; 3278 3279 /* is_mptcp should be false if subflow->conn is missing, see 3280 * subflow_syn_recv_sock() 3281 */ 3282 if (WARN_ON_ONCE(!new_mptcp_sock)) { 3283 tcp_sk(newsk)->is_mptcp = 0; 3284 goto out; 3285 } 3286 3287 newsk = new_mptcp_sock; 3288 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPCAPABLEPASSIVEACK); 3289 } else { 3290 MPTCP_INC_STATS(sock_net(ssk), 3291 MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK); 3292 } 3293 3294 out: 3295 newsk->sk_kern_sock = kern; 3296 return newsk; 3297 } 3298 3299 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags) 3300 { 3301 struct mptcp_subflow_context *subflow, *tmp; 3302 struct sock *sk = (struct sock *)msk; 3303 3304 __mptcp_clear_xmit(sk); 3305 3306 /* join list will be eventually flushed (with rst) at sock lock release time */ 3307 mptcp_for_each_subflow_safe(msk, subflow, tmp) 3308 __mptcp_close_ssk(sk, mptcp_subflow_tcp_sock(subflow), subflow, flags); 3309 3310 /* move to sk_receive_queue, sk_stream_kill_queues will purge it */ 3311 mptcp_data_lock(sk); 3312 skb_queue_splice_tail_init(&msk->receive_queue, &sk->sk_receive_queue); 3313 __skb_queue_purge(&sk->sk_receive_queue); 3314 skb_rbtree_purge(&msk->out_of_order_queue); 3315 mptcp_data_unlock(sk); 3316 3317 /* move all the rx fwd alloc into the sk_mem_reclaim_final in 3318 * inet_sock_destruct() will dispose it 3319 */ 3320 sk_forward_alloc_add(sk, msk->rmem_fwd_alloc); 3321 WRITE_ONCE(msk->rmem_fwd_alloc, 0); 3322 mptcp_token_destroy(msk); 3323 mptcp_pm_free_anno_list(msk); 3324 mptcp_free_local_addr_list(msk); 3325 } 3326 3327 static void mptcp_destroy(struct sock *sk) 3328 { 3329 struct mptcp_sock *msk = mptcp_sk(sk); 3330 3331 /* allow the following to close even the initial subflow */ 3332 msk->free_first = 1; 3333 mptcp_destroy_common(msk, 0); 3334 sk_sockets_allocated_dec(sk); 3335 } 3336 3337 void __mptcp_data_acked(struct sock *sk) 3338 { 3339 if (!sock_owned_by_user(sk)) 3340 __mptcp_clean_una(sk); 3341 else 3342 __set_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->cb_flags); 3343 3344 if (mptcp_pending_data_fin_ack(sk)) 3345 mptcp_schedule_work(sk); 3346 } 3347 3348 void __mptcp_check_push(struct sock *sk, struct sock *ssk) 3349 { 3350 if (!mptcp_send_head(sk)) 3351 return; 3352 3353 if (!sock_owned_by_user(sk)) 3354 __mptcp_subflow_push_pending(sk, ssk, false); 3355 else 3356 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3357 } 3358 3359 #define MPTCP_FLAGS_PROCESS_CTX_NEED (BIT(MPTCP_PUSH_PENDING) | \ 3360 BIT(MPTCP_RETRANSMIT) | \ 3361 BIT(MPTCP_FLUSH_JOIN_LIST)) 3362 3363 /* processes deferred events and flush wmem */ 3364 static void mptcp_release_cb(struct sock *sk) 3365 __must_hold(&sk->sk_lock.slock) 3366 { 3367 struct mptcp_sock *msk = mptcp_sk(sk); 3368 3369 for (;;) { 3370 unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) | 3371 msk->push_pending; 3372 struct list_head join_list; 3373 3374 if (!flags) 3375 break; 3376 3377 INIT_LIST_HEAD(&join_list); 3378 list_splice_init(&msk->join_list, &join_list); 3379 3380 /* the following actions acquire the subflow socket lock 3381 * 3382 * 1) can't be invoked in atomic scope 3383 * 2) must avoid ABBA deadlock with msk socket spinlock: the RX 3384 * datapath acquires the msk socket spinlock while helding 3385 * the subflow socket lock 3386 */ 3387 msk->push_pending = 0; 3388 msk->cb_flags &= ~flags; 3389 spin_unlock_bh(&sk->sk_lock.slock); 3390 3391 if (flags & BIT(MPTCP_FLUSH_JOIN_LIST)) 3392 __mptcp_flush_join_list(sk, &join_list); 3393 if (flags & BIT(MPTCP_PUSH_PENDING)) 3394 __mptcp_push_pending(sk, 0); 3395 if (flags & BIT(MPTCP_RETRANSMIT)) 3396 __mptcp_retrans(sk); 3397 3398 cond_resched(); 3399 spin_lock_bh(&sk->sk_lock.slock); 3400 } 3401 3402 if (__test_and_clear_bit(MPTCP_CLEAN_UNA, &msk->cb_flags)) 3403 __mptcp_clean_una_wakeup(sk); 3404 if (unlikely(msk->cb_flags)) { 3405 /* be sure to sync the msk state before taking actions 3406 * depending on sk_state (MPTCP_ERROR_REPORT) 3407 * On sk release avoid actions depending on the first subflow 3408 */ 3409 if (__test_and_clear_bit(MPTCP_SYNC_STATE, &msk->cb_flags) && msk->first) 3410 __mptcp_sync_state(sk, msk->pending_state); 3411 if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags)) 3412 __mptcp_error_report(sk); 3413 if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags)) 3414 __mptcp_sync_sndbuf(sk); 3415 } 3416 3417 __mptcp_update_rmem(sk); 3418 } 3419 3420 /* MP_JOIN client subflow must wait for 4th ack before sending any data: 3421 * TCP can't schedule delack timer before the subflow is fully established. 3422 * MPTCP uses the delack timer to do 3rd ack retransmissions 3423 */ 3424 static void schedule_3rdack_retransmission(struct sock *ssk) 3425 { 3426 struct inet_connection_sock *icsk = inet_csk(ssk); 3427 struct tcp_sock *tp = tcp_sk(ssk); 3428 unsigned long timeout; 3429 3430 if (mptcp_subflow_ctx(ssk)->fully_established) 3431 return; 3432 3433 /* reschedule with a timeout above RTT, as we must look only for drop */ 3434 if (tp->srtt_us) 3435 timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1)); 3436 else 3437 timeout = TCP_TIMEOUT_INIT; 3438 timeout += jiffies; 3439 3440 WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER); 3441 icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; 3442 icsk->icsk_ack.timeout = timeout; 3443 sk_reset_timer(ssk, &icsk->icsk_delack_timer, timeout); 3444 } 3445 3446 void mptcp_subflow_process_delegated(struct sock *ssk, long status) 3447 { 3448 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3449 struct sock *sk = subflow->conn; 3450 3451 if (status & BIT(MPTCP_DELEGATE_SEND)) { 3452 mptcp_data_lock(sk); 3453 if (!sock_owned_by_user(sk)) 3454 __mptcp_subflow_push_pending(sk, ssk, true); 3455 else 3456 __set_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->cb_flags); 3457 mptcp_data_unlock(sk); 3458 } 3459 if (status & BIT(MPTCP_DELEGATE_SNDBUF)) { 3460 mptcp_data_lock(sk); 3461 if (!sock_owned_by_user(sk)) 3462 __mptcp_sync_sndbuf(sk); 3463 else 3464 __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags); 3465 mptcp_data_unlock(sk); 3466 } 3467 if (status & BIT(MPTCP_DELEGATE_ACK)) 3468 schedule_3rdack_retransmission(ssk); 3469 } 3470 3471 static int mptcp_hash(struct sock *sk) 3472 { 3473 /* should never be called, 3474 * we hash the TCP subflows not the master socket 3475 */ 3476 WARN_ON_ONCE(1); 3477 return 0; 3478 } 3479 3480 static void mptcp_unhash(struct sock *sk) 3481 { 3482 /* called from sk_common_release(), but nothing to do here */ 3483 } 3484 3485 static int mptcp_get_port(struct sock *sk, unsigned short snum) 3486 { 3487 struct mptcp_sock *msk = mptcp_sk(sk); 3488 3489 pr_debug("msk=%p, ssk=%p", msk, msk->first); 3490 if (WARN_ON_ONCE(!msk->first)) 3491 return -EINVAL; 3492 3493 return inet_csk_get_port(msk->first, snum); 3494 } 3495 3496 void mptcp_finish_connect(struct sock *ssk) 3497 { 3498 struct mptcp_subflow_context *subflow; 3499 struct mptcp_sock *msk; 3500 struct sock *sk; 3501 3502 subflow = mptcp_subflow_ctx(ssk); 3503 sk = subflow->conn; 3504 msk = mptcp_sk(sk); 3505 3506 pr_debug("msk=%p, token=%u", sk, subflow->token); 3507 3508 subflow->map_seq = subflow->iasn; 3509 subflow->map_subflow_seq = 1; 3510 3511 /* the socket is not connected yet, no msk/subflow ops can access/race 3512 * accessing the field below 3513 */ 3514 WRITE_ONCE(msk->local_key, subflow->local_key); 3515 WRITE_ONCE(msk->write_seq, subflow->idsn + 1); 3516 WRITE_ONCE(msk->snd_nxt, msk->write_seq); 3517 WRITE_ONCE(msk->snd_una, msk->write_seq); 3518 3519 mptcp_pm_new_connection(msk, ssk, 0); 3520 3521 mptcp_rcv_space_init(msk, ssk); 3522 } 3523 3524 void mptcp_sock_graft(struct sock *sk, struct socket *parent) 3525 { 3526 write_lock_bh(&sk->sk_callback_lock); 3527 rcu_assign_pointer(sk->sk_wq, &parent->wq); 3528 sk_set_socket(sk, parent); 3529 sk->sk_uid = SOCK_INODE(parent)->i_uid; 3530 write_unlock_bh(&sk->sk_callback_lock); 3531 } 3532 3533 bool mptcp_finish_join(struct sock *ssk) 3534 { 3535 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 3536 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 3537 struct sock *parent = (void *)msk; 3538 bool ret = true; 3539 3540 pr_debug("msk=%p, subflow=%p", msk, subflow); 3541 3542 /* mptcp socket already closing? */ 3543 if (!mptcp_is_fully_established(parent)) { 3544 subflow->reset_reason = MPTCP_RST_EMPTCP; 3545 return false; 3546 } 3547 3548 /* active subflow, already present inside the conn_list */ 3549 if (!list_empty(&subflow->node)) { 3550 mptcp_subflow_joined(msk, ssk); 3551 mptcp_propagate_sndbuf(parent, ssk); 3552 return true; 3553 } 3554 3555 if (!mptcp_pm_allow_new_subflow(msk)) 3556 goto err_prohibited; 3557 3558 /* If we can't acquire msk socket lock here, let the release callback 3559 * handle it 3560 */ 3561 mptcp_data_lock(parent); 3562 if (!sock_owned_by_user(parent)) { 3563 ret = __mptcp_finish_join(msk, ssk); 3564 if (ret) { 3565 sock_hold(ssk); 3566 list_add_tail(&subflow->node, &msk->conn_list); 3567 } 3568 } else { 3569 sock_hold(ssk); 3570 list_add_tail(&subflow->node, &msk->join_list); 3571 __set_bit(MPTCP_FLUSH_JOIN_LIST, &msk->cb_flags); 3572 } 3573 mptcp_data_unlock(parent); 3574 3575 if (!ret) { 3576 err_prohibited: 3577 subflow->reset_reason = MPTCP_RST_EPROHIBIT; 3578 return false; 3579 } 3580 3581 return true; 3582 } 3583 3584 static void mptcp_shutdown(struct sock *sk, int how) 3585 { 3586 pr_debug("sk=%p, how=%d", sk, how); 3587 3588 if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) 3589 __mptcp_wr_shutdown(sk); 3590 } 3591 3592 static int mptcp_forward_alloc_get(const struct sock *sk) 3593 { 3594 return READ_ONCE(sk->sk_forward_alloc) + 3595 READ_ONCE(mptcp_sk(sk)->rmem_fwd_alloc); 3596 } 3597 3598 static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v) 3599 { 3600 const struct sock *sk = (void *)msk; 3601 u64 delta; 3602 3603 if (sk->sk_state == TCP_LISTEN) 3604 return -EINVAL; 3605 3606 if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) 3607 return 0; 3608 3609 delta = msk->write_seq - v; 3610 if (__mptcp_check_fallback(msk) && msk->first) { 3611 struct tcp_sock *tp = tcp_sk(msk->first); 3612 3613 /* the first subflow is disconnected after close - see 3614 * __mptcp_close_ssk(). tcp_disconnect() moves the write_seq 3615 * so ignore that status, too. 3616 */ 3617 if (!((1 << msk->first->sk_state) & 3618 (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))) 3619 delta += READ_ONCE(tp->write_seq) - tp->snd_una; 3620 } 3621 if (delta > INT_MAX) 3622 delta = INT_MAX; 3623 3624 return (int)delta; 3625 } 3626 3627 static int mptcp_ioctl(struct sock *sk, int cmd, int *karg) 3628 { 3629 struct mptcp_sock *msk = mptcp_sk(sk); 3630 bool slow; 3631 3632 switch (cmd) { 3633 case SIOCINQ: 3634 if (sk->sk_state == TCP_LISTEN) 3635 return -EINVAL; 3636 3637 lock_sock(sk); 3638 __mptcp_move_skbs(msk); 3639 *karg = mptcp_inq_hint(sk); 3640 release_sock(sk); 3641 break; 3642 case SIOCOUTQ: 3643 slow = lock_sock_fast(sk); 3644 *karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una)); 3645 unlock_sock_fast(sk, slow); 3646 break; 3647 case SIOCOUTQNSD: 3648 slow = lock_sock_fast(sk); 3649 *karg = mptcp_ioctl_outq(msk, msk->snd_nxt); 3650 unlock_sock_fast(sk, slow); 3651 break; 3652 default: 3653 return -ENOIOCTLCMD; 3654 } 3655 3656 return 0; 3657 } 3658 3659 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk, 3660 struct mptcp_subflow_context *subflow) 3661 { 3662 subflow->request_mptcp = 0; 3663 __mptcp_do_fallback(msk); 3664 } 3665 3666 static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) 3667 { 3668 struct mptcp_subflow_context *subflow; 3669 struct mptcp_sock *msk = mptcp_sk(sk); 3670 int err = -EINVAL; 3671 struct sock *ssk; 3672 3673 ssk = __mptcp_nmpc_sk(msk); 3674 if (IS_ERR(ssk)) 3675 return PTR_ERR(ssk); 3676 3677 inet_sk_state_store(sk, TCP_SYN_SENT); 3678 subflow = mptcp_subflow_ctx(ssk); 3679 #ifdef CONFIG_TCP_MD5SIG 3680 /* no MPTCP if MD5SIG is enabled on this socket or we may run out of 3681 * TCP option space. 3682 */ 3683 if (rcu_access_pointer(tcp_sk(ssk)->md5sig_info)) 3684 mptcp_subflow_early_fallback(msk, subflow); 3685 #endif 3686 if (subflow->request_mptcp && mptcp_token_new_connect(ssk)) { 3687 MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_TOKENFALLBACKINIT); 3688 mptcp_subflow_early_fallback(msk, subflow); 3689 } 3690 if (likely(!__mptcp_check_fallback(msk))) 3691 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVE); 3692 3693 /* if reaching here via the fastopen/sendmsg path, the caller already 3694 * acquired the subflow socket lock, too. 3695 */ 3696 if (!msk->fastopening) 3697 lock_sock(ssk); 3698 3699 /* the following mirrors closely a very small chunk of code from 3700 * __inet_stream_connect() 3701 */ 3702 if (ssk->sk_state != TCP_CLOSE) 3703 goto out; 3704 3705 if (BPF_CGROUP_PRE_CONNECT_ENABLED(ssk)) { 3706 err = ssk->sk_prot->pre_connect(ssk, uaddr, addr_len); 3707 if (err) 3708 goto out; 3709 } 3710 3711 err = ssk->sk_prot->connect(ssk, uaddr, addr_len); 3712 if (err < 0) 3713 goto out; 3714 3715 inet_assign_bit(DEFER_CONNECT, sk, inet_test_bit(DEFER_CONNECT, ssk)); 3716 3717 out: 3718 if (!msk->fastopening) 3719 release_sock(ssk); 3720 3721 /* on successful connect, the msk state will be moved to established by 3722 * subflow_finish_connect() 3723 */ 3724 if (unlikely(err)) { 3725 /* avoid leaving a dangling token in an unconnected socket */ 3726 mptcp_token_destroy(msk); 3727 inet_sk_state_store(sk, TCP_CLOSE); 3728 return err; 3729 } 3730 3731 mptcp_copy_inaddrs(sk, ssk); 3732 return 0; 3733 } 3734 3735 static struct proto mptcp_prot = { 3736 .name = "MPTCP", 3737 .owner = THIS_MODULE, 3738 .init = mptcp_init_sock, 3739 .connect = mptcp_connect, 3740 .disconnect = mptcp_disconnect, 3741 .close = mptcp_close, 3742 .accept = mptcp_accept, 3743 .setsockopt = mptcp_setsockopt, 3744 .getsockopt = mptcp_getsockopt, 3745 .shutdown = mptcp_shutdown, 3746 .destroy = mptcp_destroy, 3747 .sendmsg = mptcp_sendmsg, 3748 .ioctl = mptcp_ioctl, 3749 .recvmsg = mptcp_recvmsg, 3750 .release_cb = mptcp_release_cb, 3751 .hash = mptcp_hash, 3752 .unhash = mptcp_unhash, 3753 .get_port = mptcp_get_port, 3754 .forward_alloc_get = mptcp_forward_alloc_get, 3755 .sockets_allocated = &mptcp_sockets_allocated, 3756 3757 .memory_allocated = &tcp_memory_allocated, 3758 .per_cpu_fw_alloc = &tcp_memory_per_cpu_fw_alloc, 3759 3760 .memory_pressure = &tcp_memory_pressure, 3761 .sysctl_wmem_offset = offsetof(struct net, ipv4.sysctl_tcp_wmem), 3762 .sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_tcp_rmem), 3763 .sysctl_mem = sysctl_tcp_mem, 3764 .obj_size = sizeof(struct mptcp_sock), 3765 .slab_flags = SLAB_TYPESAFE_BY_RCU, 3766 .no_autobind = true, 3767 }; 3768 3769 static int mptcp_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 3770 { 3771 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3772 struct sock *ssk, *sk = sock->sk; 3773 int err = -EINVAL; 3774 3775 lock_sock(sk); 3776 ssk = __mptcp_nmpc_sk(msk); 3777 if (IS_ERR(ssk)) { 3778 err = PTR_ERR(ssk); 3779 goto unlock; 3780 } 3781 3782 if (sk->sk_family == AF_INET) 3783 err = inet_bind_sk(ssk, uaddr, addr_len); 3784 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 3785 else if (sk->sk_family == AF_INET6) 3786 err = inet6_bind_sk(ssk, uaddr, addr_len); 3787 #endif 3788 if (!err) 3789 mptcp_copy_inaddrs(sk, ssk); 3790 3791 unlock: 3792 release_sock(sk); 3793 return err; 3794 } 3795 3796 static int mptcp_listen(struct socket *sock, int backlog) 3797 { 3798 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3799 struct sock *sk = sock->sk; 3800 struct sock *ssk; 3801 int err; 3802 3803 pr_debug("msk=%p", msk); 3804 3805 lock_sock(sk); 3806 3807 err = -EINVAL; 3808 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM) 3809 goto unlock; 3810 3811 ssk = __mptcp_nmpc_sk(msk); 3812 if (IS_ERR(ssk)) { 3813 err = PTR_ERR(ssk); 3814 goto unlock; 3815 } 3816 3817 inet_sk_state_store(sk, TCP_LISTEN); 3818 sock_set_flag(sk, SOCK_RCU_FREE); 3819 3820 lock_sock(ssk); 3821 err = __inet_listen_sk(ssk, backlog); 3822 release_sock(ssk); 3823 inet_sk_state_store(sk, inet_sk_state_load(ssk)); 3824 3825 if (!err) { 3826 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 3827 mptcp_copy_inaddrs(sk, ssk); 3828 mptcp_event_pm_listener(ssk, MPTCP_EVENT_LISTENER_CREATED); 3829 } 3830 3831 unlock: 3832 release_sock(sk); 3833 return err; 3834 } 3835 3836 static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, 3837 int flags, bool kern) 3838 { 3839 struct mptcp_sock *msk = mptcp_sk(sock->sk); 3840 struct sock *ssk, *newsk; 3841 int err; 3842 3843 pr_debug("msk=%p", msk); 3844 3845 /* Buggy applications can call accept on socket states other then LISTEN 3846 * but no need to allocate the first subflow just to error out. 3847 */ 3848 ssk = READ_ONCE(msk->first); 3849 if (!ssk) 3850 return -EINVAL; 3851 3852 newsk = mptcp_accept(ssk, flags, &err, kern); 3853 if (!newsk) 3854 return err; 3855 3856 lock_sock(newsk); 3857 3858 __inet_accept(sock, newsock, newsk); 3859 if (!mptcp_is_tcpsk(newsock->sk)) { 3860 struct mptcp_sock *msk = mptcp_sk(newsk); 3861 struct mptcp_subflow_context *subflow; 3862 3863 set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags); 3864 msk->in_accept_queue = 0; 3865 3866 /* set ssk->sk_socket of accept()ed flows to mptcp socket. 3867 * This is needed so NOSPACE flag can be set from tcp stack. 3868 */ 3869 mptcp_for_each_subflow(msk, subflow) { 3870 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3871 3872 if (!ssk->sk_socket) 3873 mptcp_sock_graft(ssk, newsock); 3874 } 3875 3876 /* Do late cleanup for the first subflow as necessary. Also 3877 * deal with bad peers not doing a complete shutdown. 3878 */ 3879 if (unlikely(inet_sk_state_load(msk->first) == TCP_CLOSE)) { 3880 __mptcp_close_ssk(newsk, msk->first, 3881 mptcp_subflow_ctx(msk->first), 0); 3882 if (unlikely(list_is_singular(&msk->conn_list))) 3883 inet_sk_state_store(newsk, TCP_CLOSE); 3884 } 3885 } 3886 release_sock(newsk); 3887 3888 return 0; 3889 } 3890 3891 static __poll_t mptcp_check_writeable(struct mptcp_sock *msk) 3892 { 3893 struct sock *sk = (struct sock *)msk; 3894 3895 if (sk_stream_is_writeable(sk)) 3896 return EPOLLOUT | EPOLLWRNORM; 3897 3898 mptcp_set_nospace(sk); 3899 smp_mb__after_atomic(); /* msk->flags is changed by write_space cb */ 3900 if (sk_stream_is_writeable(sk)) 3901 return EPOLLOUT | EPOLLWRNORM; 3902 3903 return 0; 3904 } 3905 3906 static __poll_t mptcp_poll(struct file *file, struct socket *sock, 3907 struct poll_table_struct *wait) 3908 { 3909 struct sock *sk = sock->sk; 3910 struct mptcp_sock *msk; 3911 __poll_t mask = 0; 3912 u8 shutdown; 3913 int state; 3914 3915 msk = mptcp_sk(sk); 3916 sock_poll_wait(file, sock, wait); 3917 3918 state = inet_sk_state_load(sk); 3919 pr_debug("msk=%p state=%d flags=%lx", msk, state, msk->flags); 3920 if (state == TCP_LISTEN) { 3921 struct sock *ssk = READ_ONCE(msk->first); 3922 3923 if (WARN_ON_ONCE(!ssk)) 3924 return 0; 3925 3926 return inet_csk_listen_poll(ssk); 3927 } 3928 3929 shutdown = READ_ONCE(sk->sk_shutdown); 3930 if (shutdown == SHUTDOWN_MASK || state == TCP_CLOSE) 3931 mask |= EPOLLHUP; 3932 if (shutdown & RCV_SHUTDOWN) 3933 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP; 3934 3935 if (state != TCP_SYN_SENT && state != TCP_SYN_RECV) { 3936 mask |= mptcp_check_readable(sk); 3937 if (shutdown & SEND_SHUTDOWN) 3938 mask |= EPOLLOUT | EPOLLWRNORM; 3939 else 3940 mask |= mptcp_check_writeable(msk); 3941 } else if (state == TCP_SYN_SENT && 3942 inet_test_bit(DEFER_CONNECT, sk)) { 3943 /* cf tcp_poll() note about TFO */ 3944 mask |= EPOLLOUT | EPOLLWRNORM; 3945 } 3946 3947 /* This barrier is coupled with smp_wmb() in __mptcp_error_report() */ 3948 smp_rmb(); 3949 if (READ_ONCE(sk->sk_err)) 3950 mask |= EPOLLERR; 3951 3952 return mask; 3953 } 3954 3955 static const struct proto_ops mptcp_stream_ops = { 3956 .family = PF_INET, 3957 .owner = THIS_MODULE, 3958 .release = inet_release, 3959 .bind = mptcp_bind, 3960 .connect = inet_stream_connect, 3961 .socketpair = sock_no_socketpair, 3962 .accept = mptcp_stream_accept, 3963 .getname = inet_getname, 3964 .poll = mptcp_poll, 3965 .ioctl = inet_ioctl, 3966 .gettstamp = sock_gettstamp, 3967 .listen = mptcp_listen, 3968 .shutdown = inet_shutdown, 3969 .setsockopt = sock_common_setsockopt, 3970 .getsockopt = sock_common_getsockopt, 3971 .sendmsg = inet_sendmsg, 3972 .recvmsg = inet_recvmsg, 3973 .mmap = sock_no_mmap, 3974 .set_rcvlowat = mptcp_set_rcvlowat, 3975 }; 3976 3977 static struct inet_protosw mptcp_protosw = { 3978 .type = SOCK_STREAM, 3979 .protocol = IPPROTO_MPTCP, 3980 .prot = &mptcp_prot, 3981 .ops = &mptcp_stream_ops, 3982 .flags = INET_PROTOSW_ICSK, 3983 }; 3984 3985 static int mptcp_napi_poll(struct napi_struct *napi, int budget) 3986 { 3987 struct mptcp_delegated_action *delegated; 3988 struct mptcp_subflow_context *subflow; 3989 int work_done = 0; 3990 3991 delegated = container_of(napi, struct mptcp_delegated_action, napi); 3992 while ((subflow = mptcp_subflow_delegated_next(delegated)) != NULL) { 3993 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 3994 3995 bh_lock_sock_nested(ssk); 3996 if (!sock_owned_by_user(ssk)) { 3997 mptcp_subflow_process_delegated(ssk, xchg(&subflow->delegated_status, 0)); 3998 } else { 3999 /* tcp_release_cb_override already processed 4000 * the action or will do at next release_sock(). 4001 * In both case must dequeue the subflow here - on the same 4002 * CPU that scheduled it. 4003 */ 4004 smp_wmb(); 4005 clear_bit(MPTCP_DELEGATE_SCHEDULED, &subflow->delegated_status); 4006 } 4007 bh_unlock_sock(ssk); 4008 sock_put(ssk); 4009 4010 if (++work_done == budget) 4011 return budget; 4012 } 4013 4014 /* always provide a 0 'work_done' argument, so that napi_complete_done 4015 * will not try accessing the NULL napi->dev ptr 4016 */ 4017 napi_complete_done(napi, 0); 4018 return work_done; 4019 } 4020 4021 void __init mptcp_proto_init(void) 4022 { 4023 struct mptcp_delegated_action *delegated; 4024 int cpu; 4025 4026 mptcp_prot.h.hashinfo = tcp_prot.h.hashinfo; 4027 4028 if (percpu_counter_init(&mptcp_sockets_allocated, 0, GFP_KERNEL)) 4029 panic("Failed to allocate MPTCP pcpu counter\n"); 4030 4031 init_dummy_netdev(&mptcp_napi_dev); 4032 for_each_possible_cpu(cpu) { 4033 delegated = per_cpu_ptr(&mptcp_delegated_actions, cpu); 4034 INIT_LIST_HEAD(&delegated->head); 4035 netif_napi_add_tx(&mptcp_napi_dev, &delegated->napi, 4036 mptcp_napi_poll); 4037 napi_enable(&delegated->napi); 4038 } 4039 4040 mptcp_subflow_init(); 4041 mptcp_pm_init(); 4042 mptcp_sched_init(); 4043 mptcp_token_init(); 4044 4045 if (proto_register(&mptcp_prot, 1) != 0) 4046 panic("Failed to register MPTCP proto.\n"); 4047 4048 inet_register_protosw(&mptcp_protosw); 4049 4050 BUILD_BUG_ON(sizeof(struct mptcp_skb_cb) > sizeof_field(struct sk_buff, cb)); 4051 } 4052 4053 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 4054 static const struct proto_ops mptcp_v6_stream_ops = { 4055 .family = PF_INET6, 4056 .owner = THIS_MODULE, 4057 .release = inet6_release, 4058 .bind = mptcp_bind, 4059 .connect = inet_stream_connect, 4060 .socketpair = sock_no_socketpair, 4061 .accept = mptcp_stream_accept, 4062 .getname = inet6_getname, 4063 .poll = mptcp_poll, 4064 .ioctl = inet6_ioctl, 4065 .gettstamp = sock_gettstamp, 4066 .listen = mptcp_listen, 4067 .shutdown = inet_shutdown, 4068 .setsockopt = sock_common_setsockopt, 4069 .getsockopt = sock_common_getsockopt, 4070 .sendmsg = inet6_sendmsg, 4071 .recvmsg = inet6_recvmsg, 4072 .mmap = sock_no_mmap, 4073 #ifdef CONFIG_COMPAT 4074 .compat_ioctl = inet6_compat_ioctl, 4075 #endif 4076 .set_rcvlowat = mptcp_set_rcvlowat, 4077 }; 4078 4079 static struct proto mptcp_v6_prot; 4080 4081 static struct inet_protosw mptcp_v6_protosw = { 4082 .type = SOCK_STREAM, 4083 .protocol = IPPROTO_MPTCP, 4084 .prot = &mptcp_v6_prot, 4085 .ops = &mptcp_v6_stream_ops, 4086 .flags = INET_PROTOSW_ICSK, 4087 }; 4088 4089 int __init mptcp_proto_v6_init(void) 4090 { 4091 int err; 4092 4093 mptcp_v6_prot = mptcp_prot; 4094 strcpy(mptcp_v6_prot.name, "MPTCPv6"); 4095 mptcp_v6_prot.slab = NULL; 4096 mptcp_v6_prot.obj_size = sizeof(struct mptcp6_sock); 4097 mptcp_v6_prot.ipv6_pinfo_offset = offsetof(struct mptcp6_sock, np); 4098 4099 err = proto_register(&mptcp_v6_prot, 1); 4100 if (err) 4101 return err; 4102 4103 err = inet6_register_protosw(&mptcp_v6_protosw); 4104 if (err) 4105 proto_unregister(&mptcp_v6_prot); 4106 4107 return err; 4108 } 4109 #endif 4110