1 // SPDX-License-Identifier: GPL-2.0 2 /* Multipath TCP 3 * 4 * Copyright (c) 2019, Intel Corporation. 5 */ 6 #define pr_fmt(fmt) "MPTCP: " fmt 7 8 #include <linux/rculist.h> 9 #include <linux/spinlock.h> 10 #include "protocol.h" 11 #include "mib.h" 12 13 #define ADD_ADDR_RETRANS_MAX 3 14 15 struct mptcp_pm_add_entry { 16 struct list_head list; 17 struct mptcp_addr_info addr; 18 u8 retrans_times; 19 struct timer_list add_timer; 20 struct mptcp_sock *sock; 21 }; 22 23 static DEFINE_SPINLOCK(mptcp_pm_list_lock); 24 static LIST_HEAD(mptcp_pm_list); 25 26 /* path manager helpers */ 27 28 /* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses, 29 * otherwise allow any matching local/remote pair 30 */ 31 bool mptcp_pm_addr_families_match(const struct sock *sk, 32 const struct mptcp_addr_info *loc, 33 const struct mptcp_addr_info *rem) 34 { 35 bool mptcp_is_v4 = sk->sk_family == AF_INET; 36 37 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 38 bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6); 39 bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6); 40 41 if (mptcp_is_v4) 42 return loc_is_v4 && rem_is_v4; 43 44 if (ipv6_only_sock(sk)) 45 return !loc_is_v4 && !rem_is_v4; 46 47 return loc_is_v4 == rem_is_v4; 48 #else 49 return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET; 50 #endif 51 } 52 53 bool mptcp_addresses_equal(const struct mptcp_addr_info *a, 54 const struct mptcp_addr_info *b, bool use_port) 55 { 56 bool addr_equals = false; 57 58 if (a->family == b->family) { 59 if (a->family == AF_INET) 60 addr_equals = a->addr.s_addr == b->addr.s_addr; 61 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 62 else 63 addr_equals = ipv6_addr_equal(&a->addr6, &b->addr6); 64 } else if (a->family == AF_INET) { 65 if (ipv6_addr_v4mapped(&b->addr6)) 66 addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3]; 67 } else if (b->family == AF_INET) { 68 if (ipv6_addr_v4mapped(&a->addr6)) 69 addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr; 70 #endif 71 } 72 73 if (!addr_equals) 74 return false; 75 if (!use_port) 76 return true; 77 78 return a->port == b->port; 79 } 80 81 void mptcp_local_address(const struct sock_common *skc, 82 struct mptcp_addr_info *addr) 83 { 84 addr->family = skc->skc_family; 85 addr->port = htons(skc->skc_num); 86 if (addr->family == AF_INET) 87 addr->addr.s_addr = skc->skc_rcv_saddr; 88 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 89 else if (addr->family == AF_INET6) 90 addr->addr6 = skc->skc_v6_rcv_saddr; 91 #endif 92 } 93 94 void mptcp_remote_address(const struct sock_common *skc, 95 struct mptcp_addr_info *addr) 96 { 97 addr->family = skc->skc_family; 98 addr->port = skc->skc_dport; 99 if (addr->family == AF_INET) 100 addr->addr.s_addr = skc->skc_daddr; 101 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 102 else if (addr->family == AF_INET6) 103 addr->addr6 = skc->skc_v6_daddr; 104 #endif 105 } 106 107 static bool mptcp_pm_is_init_remote_addr(struct mptcp_sock *msk, 108 const struct mptcp_addr_info *remote) 109 { 110 struct mptcp_addr_info mpc_remote; 111 112 mptcp_remote_address((struct sock_common *)msk, &mpc_remote); 113 return mptcp_addresses_equal(&mpc_remote, remote, remote->port); 114 } 115 116 bool mptcp_lookup_subflow_by_saddr(const struct list_head *list, 117 const struct mptcp_addr_info *saddr) 118 { 119 struct mptcp_subflow_context *subflow; 120 struct mptcp_addr_info cur; 121 struct sock_common *skc; 122 123 list_for_each_entry(subflow, list, node) { 124 skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow); 125 126 mptcp_local_address(skc, &cur); 127 if (mptcp_addresses_equal(&cur, saddr, saddr->port)) 128 return true; 129 } 130 131 return false; 132 } 133 134 static struct mptcp_pm_add_entry * 135 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk, 136 const struct mptcp_addr_info *addr) 137 { 138 struct mptcp_pm_add_entry *entry; 139 140 lockdep_assert_held(&msk->pm.lock); 141 142 list_for_each_entry(entry, &msk->pm.anno_list, list) { 143 if (mptcp_addresses_equal(&entry->addr, addr, true)) 144 return entry; 145 } 146 147 return NULL; 148 } 149 150 bool mptcp_remove_anno_list_by_saddr(struct mptcp_sock *msk, 151 const struct mptcp_addr_info *addr) 152 { 153 struct mptcp_pm_add_entry *entry; 154 bool ret; 155 156 entry = mptcp_pm_del_add_timer(msk, addr, false); 157 ret = entry; 158 kfree(entry); 159 160 return ret; 161 } 162 163 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk) 164 { 165 struct mptcp_pm_add_entry *entry; 166 struct mptcp_addr_info saddr; 167 bool ret = false; 168 169 mptcp_local_address((struct sock_common *)sk, &saddr); 170 171 spin_lock_bh(&msk->pm.lock); 172 list_for_each_entry(entry, &msk->pm.anno_list, list) { 173 if (mptcp_addresses_equal(&entry->addr, &saddr, true)) { 174 ret = true; 175 goto out; 176 } 177 } 178 179 out: 180 spin_unlock_bh(&msk->pm.lock); 181 return ret; 182 } 183 184 static void __mptcp_pm_send_ack(struct mptcp_sock *msk, 185 struct mptcp_subflow_context *subflow, 186 bool prio, bool backup) 187 { 188 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 189 bool slow; 190 191 pr_debug("send ack for %s\n", 192 prio ? "mp_prio" : 193 (mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr")); 194 195 slow = lock_sock_fast(ssk); 196 if (prio) { 197 subflow->send_mp_prio = 1; 198 subflow->request_bkup = backup; 199 } 200 201 __mptcp_subflow_send_ack(ssk); 202 unlock_sock_fast(ssk, slow); 203 } 204 205 void mptcp_pm_send_ack(struct mptcp_sock *msk, 206 struct mptcp_subflow_context *subflow, 207 bool prio, bool backup) 208 { 209 spin_unlock_bh(&msk->pm.lock); 210 __mptcp_pm_send_ack(msk, subflow, prio, backup); 211 spin_lock_bh(&msk->pm.lock); 212 } 213 214 void mptcp_pm_addr_send_ack(struct mptcp_sock *msk) 215 { 216 struct mptcp_subflow_context *subflow, *alt = NULL; 217 218 msk_owned_by_me(msk); 219 lockdep_assert_held(&msk->pm.lock); 220 221 if (!mptcp_pm_should_add_signal(msk) && 222 !mptcp_pm_should_rm_signal(msk)) 223 return; 224 225 mptcp_for_each_subflow(msk, subflow) { 226 if (__mptcp_subflow_active(subflow)) { 227 if (!subflow->stale) { 228 mptcp_pm_send_ack(msk, subflow, false, false); 229 return; 230 } 231 232 if (!alt) 233 alt = subflow; 234 } 235 } 236 237 if (alt) 238 mptcp_pm_send_ack(msk, alt, false, false); 239 } 240 241 int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk, 242 struct mptcp_addr_info *addr, 243 struct mptcp_addr_info *rem, 244 u8 bkup) 245 { 246 struct mptcp_subflow_context *subflow; 247 248 pr_debug("bkup=%d\n", bkup); 249 250 mptcp_for_each_subflow(msk, subflow) { 251 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 252 struct mptcp_addr_info local, remote; 253 254 mptcp_local_address((struct sock_common *)ssk, &local); 255 if (!mptcp_addresses_equal(&local, addr, addr->port)) 256 continue; 257 258 if (rem && rem->family != AF_UNSPEC) { 259 mptcp_remote_address((struct sock_common *)ssk, &remote); 260 if (!mptcp_addresses_equal(&remote, rem, rem->port)) 261 continue; 262 } 263 264 __mptcp_pm_send_ack(msk, subflow, true, bkup); 265 return 0; 266 } 267 268 return -EINVAL; 269 } 270 271 static void mptcp_pm_add_timer(struct timer_list *timer) 272 { 273 struct mptcp_pm_add_entry *entry = timer_container_of(entry, timer, 274 add_timer); 275 struct mptcp_sock *msk = entry->sock; 276 struct sock *sk = (struct sock *)msk; 277 278 pr_debug("msk=%p\n", msk); 279 280 if (!msk) 281 return; 282 283 if (inet_sk_state_load(sk) == TCP_CLOSE) 284 return; 285 286 if (!entry->addr.id) 287 return; 288 289 if (mptcp_pm_should_add_signal_addr(msk)) { 290 sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8); 291 goto out; 292 } 293 294 spin_lock_bh(&msk->pm.lock); 295 296 if (!mptcp_pm_should_add_signal_addr(msk)) { 297 pr_debug("retransmit ADD_ADDR id=%d\n", entry->addr.id); 298 mptcp_pm_announce_addr(msk, &entry->addr, false); 299 mptcp_pm_add_addr_send_ack(msk); 300 entry->retrans_times++; 301 } 302 303 if (entry->retrans_times < ADD_ADDR_RETRANS_MAX) 304 sk_reset_timer(sk, timer, 305 jiffies + mptcp_get_add_addr_timeout(sock_net(sk))); 306 307 spin_unlock_bh(&msk->pm.lock); 308 309 if (entry->retrans_times == ADD_ADDR_RETRANS_MAX) 310 mptcp_pm_subflow_established(msk); 311 312 out: 313 __sock_put(sk); 314 } 315 316 struct mptcp_pm_add_entry * 317 mptcp_pm_del_add_timer(struct mptcp_sock *msk, 318 const struct mptcp_addr_info *addr, bool check_id) 319 { 320 struct mptcp_pm_add_entry *entry; 321 struct sock *sk = (struct sock *)msk; 322 struct timer_list *add_timer = NULL; 323 324 spin_lock_bh(&msk->pm.lock); 325 entry = mptcp_lookup_anno_list_by_saddr(msk, addr); 326 if (entry && (!check_id || entry->addr.id == addr->id)) { 327 entry->retrans_times = ADD_ADDR_RETRANS_MAX; 328 add_timer = &entry->add_timer; 329 } 330 if (!check_id && entry) 331 list_del(&entry->list); 332 spin_unlock_bh(&msk->pm.lock); 333 334 /* no lock, because sk_stop_timer_sync() is calling timer_delete_sync() */ 335 if (add_timer) 336 sk_stop_timer_sync(sk, add_timer); 337 338 return entry; 339 } 340 341 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk, 342 const struct mptcp_addr_info *addr) 343 { 344 struct mptcp_pm_add_entry *add_entry = NULL; 345 struct sock *sk = (struct sock *)msk; 346 struct net *net = sock_net(sk); 347 348 lockdep_assert_held(&msk->pm.lock); 349 350 add_entry = mptcp_lookup_anno_list_by_saddr(msk, addr); 351 352 if (add_entry) { 353 if (WARN_ON_ONCE(mptcp_pm_is_kernel(msk))) 354 return false; 355 356 sk_reset_timer(sk, &add_entry->add_timer, 357 jiffies + mptcp_get_add_addr_timeout(net)); 358 return true; 359 } 360 361 add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC); 362 if (!add_entry) 363 return false; 364 365 list_add(&add_entry->list, &msk->pm.anno_list); 366 367 add_entry->addr = *addr; 368 add_entry->sock = msk; 369 add_entry->retrans_times = 0; 370 371 timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0); 372 sk_reset_timer(sk, &add_entry->add_timer, 373 jiffies + mptcp_get_add_addr_timeout(net)); 374 375 return true; 376 } 377 378 static void mptcp_pm_free_anno_list(struct mptcp_sock *msk) 379 { 380 struct mptcp_pm_add_entry *entry, *tmp; 381 struct sock *sk = (struct sock *)msk; 382 LIST_HEAD(free_list); 383 384 pr_debug("msk=%p\n", msk); 385 386 spin_lock_bh(&msk->pm.lock); 387 list_splice_init(&msk->pm.anno_list, &free_list); 388 spin_unlock_bh(&msk->pm.lock); 389 390 list_for_each_entry_safe(entry, tmp, &free_list, list) { 391 sk_stop_timer_sync(sk, &entry->add_timer); 392 kfree(entry); 393 } 394 } 395 396 /* path manager command handlers */ 397 398 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 399 const struct mptcp_addr_info *addr, 400 bool echo) 401 { 402 u8 add_addr = READ_ONCE(msk->pm.addr_signal); 403 404 pr_debug("msk=%p, local_id=%d, echo=%d\n", msk, addr->id, echo); 405 406 lockdep_assert_held(&msk->pm.lock); 407 408 if (add_addr & 409 (echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) { 410 MPTCP_INC_STATS(sock_net((struct sock *)msk), 411 echo ? MPTCP_MIB_ECHOADDTXDROP : MPTCP_MIB_ADDADDRTXDROP); 412 return -EINVAL; 413 } 414 415 if (echo) { 416 msk->pm.remote = *addr; 417 add_addr |= BIT(MPTCP_ADD_ADDR_ECHO); 418 } else { 419 msk->pm.local = *addr; 420 add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL); 421 } 422 WRITE_ONCE(msk->pm.addr_signal, add_addr); 423 return 0; 424 } 425 426 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list) 427 { 428 u8 rm_addr = READ_ONCE(msk->pm.addr_signal); 429 430 pr_debug("msk=%p, rm_list_nr=%d\n", msk, rm_list->nr); 431 432 if (rm_addr) { 433 MPTCP_ADD_STATS(sock_net((struct sock *)msk), 434 MPTCP_MIB_RMADDRTXDROP, rm_list->nr); 435 return -EINVAL; 436 } 437 438 msk->pm.rm_list_tx = *rm_list; 439 rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL); 440 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 441 mptcp_pm_addr_send_ack(msk); 442 return 0; 443 } 444 445 /* path manager event handlers */ 446 447 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side) 448 { 449 struct mptcp_pm_data *pm = &msk->pm; 450 451 pr_debug("msk=%p, token=%u side=%d\n", msk, READ_ONCE(msk->token), server_side); 452 453 WRITE_ONCE(pm->server_side, server_side); 454 mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC); 455 } 456 457 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) 458 { 459 struct mptcp_pm_data *pm = &msk->pm; 460 unsigned int subflows_max; 461 int ret = 0; 462 463 if (mptcp_pm_is_userspace(msk)) { 464 if (mptcp_userspace_pm_active(msk)) { 465 spin_lock_bh(&pm->lock); 466 pm->subflows++; 467 spin_unlock_bh(&pm->lock); 468 return true; 469 } 470 return false; 471 } 472 473 subflows_max = mptcp_pm_get_subflows_max(msk); 474 475 pr_debug("msk=%p subflows=%d max=%d allow=%d\n", msk, pm->subflows, 476 subflows_max, READ_ONCE(pm->accept_subflow)); 477 478 /* try to avoid acquiring the lock below */ 479 if (!READ_ONCE(pm->accept_subflow)) 480 return false; 481 482 spin_lock_bh(&pm->lock); 483 if (READ_ONCE(pm->accept_subflow)) { 484 ret = pm->subflows < subflows_max; 485 if (ret && ++pm->subflows == subflows_max) 486 WRITE_ONCE(pm->accept_subflow, false); 487 } 488 spin_unlock_bh(&pm->lock); 489 490 return ret; 491 } 492 493 /* return true if the new status bit is currently cleared, that is, this event 494 * can be server, eventually by an already scheduled work 495 */ 496 static bool mptcp_pm_schedule_work(struct mptcp_sock *msk, 497 enum mptcp_pm_status new_status) 498 { 499 pr_debug("msk=%p status=%x new=%lx\n", msk, msk->pm.status, 500 BIT(new_status)); 501 if (msk->pm.status & BIT(new_status)) 502 return false; 503 504 msk->pm.status |= BIT(new_status); 505 mptcp_schedule_work((struct sock *)msk); 506 return true; 507 } 508 509 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk) 510 { 511 struct mptcp_pm_data *pm = &msk->pm; 512 bool announce = false; 513 514 pr_debug("msk=%p\n", msk); 515 516 spin_lock_bh(&pm->lock); 517 518 /* mptcp_pm_fully_established() can be invoked by multiple 519 * racing paths - accept() and check_fully_established() 520 * be sure to serve this event only once. 521 */ 522 if (READ_ONCE(pm->work_pending) && 523 !(pm->status & BIT(MPTCP_PM_ALREADY_ESTABLISHED))) 524 mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED); 525 526 if ((pm->status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0) 527 announce = true; 528 529 pm->status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED); 530 spin_unlock_bh(&pm->lock); 531 532 if (announce) 533 mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, GFP_ATOMIC); 534 } 535 536 void mptcp_pm_connection_closed(struct mptcp_sock *msk) 537 { 538 pr_debug("msk=%p\n", msk); 539 540 if (msk->token) 541 mptcp_event(MPTCP_EVENT_CLOSED, msk, NULL, GFP_KERNEL); 542 } 543 544 void mptcp_pm_subflow_established(struct mptcp_sock *msk) 545 { 546 struct mptcp_pm_data *pm = &msk->pm; 547 548 pr_debug("msk=%p\n", msk); 549 550 if (!READ_ONCE(pm->work_pending)) 551 return; 552 553 spin_lock_bh(&pm->lock); 554 555 if (READ_ONCE(pm->work_pending)) 556 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 557 558 spin_unlock_bh(&pm->lock); 559 } 560 561 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, 562 const struct mptcp_subflow_context *subflow) 563 { 564 struct mptcp_pm_data *pm = &msk->pm; 565 bool update_subflows; 566 567 update_subflows = subflow->request_join || subflow->mp_join; 568 if (mptcp_pm_is_userspace(msk)) { 569 if (update_subflows) { 570 spin_lock_bh(&pm->lock); 571 pm->subflows--; 572 spin_unlock_bh(&pm->lock); 573 } 574 return; 575 } 576 577 if (!READ_ONCE(pm->work_pending) && !update_subflows) 578 return; 579 580 spin_lock_bh(&pm->lock); 581 if (update_subflows) 582 __mptcp_pm_close_subflow(msk); 583 584 /* Even if this subflow is not really established, tell the PM to try 585 * to pick the next ones, if possible. 586 */ 587 if (mptcp_pm_nl_check_work_pending(msk)) 588 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 589 590 spin_unlock_bh(&pm->lock); 591 } 592 593 void mptcp_pm_add_addr_received(const struct sock *ssk, 594 const struct mptcp_addr_info *addr) 595 { 596 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 597 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 598 struct mptcp_pm_data *pm = &msk->pm; 599 600 pr_debug("msk=%p remote_id=%d accept=%d\n", msk, addr->id, 601 READ_ONCE(pm->accept_addr)); 602 603 mptcp_event_addr_announced(ssk, addr); 604 605 spin_lock_bh(&pm->lock); 606 607 if (mptcp_pm_is_userspace(msk)) { 608 if (mptcp_userspace_pm_active(msk)) { 609 mptcp_pm_announce_addr(msk, addr, true); 610 mptcp_pm_add_addr_send_ack(msk); 611 } else { 612 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 613 } 614 /* id0 should not have a different address */ 615 } else if ((addr->id == 0 && !mptcp_pm_is_init_remote_addr(msk, addr)) || 616 (addr->id > 0 && !READ_ONCE(pm->accept_addr))) { 617 mptcp_pm_announce_addr(msk, addr, true); 618 mptcp_pm_add_addr_send_ack(msk); 619 } else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) { 620 pm->remote = *addr; 621 } else { 622 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 623 } 624 625 spin_unlock_bh(&pm->lock); 626 } 627 628 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, 629 const struct mptcp_addr_info *addr) 630 { 631 struct mptcp_pm_data *pm = &msk->pm; 632 633 pr_debug("msk=%p\n", msk); 634 635 if (!READ_ONCE(pm->work_pending)) 636 return; 637 638 spin_lock_bh(&pm->lock); 639 640 if (mptcp_lookup_anno_list_by_saddr(msk, addr) && READ_ONCE(pm->work_pending)) 641 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 642 643 spin_unlock_bh(&pm->lock); 644 } 645 646 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk) 647 { 648 if (!mptcp_pm_should_add_signal(msk)) 649 return; 650 651 mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK); 652 } 653 654 static void mptcp_pm_rm_addr_or_subflow(struct mptcp_sock *msk, 655 const struct mptcp_rm_list *rm_list, 656 enum linux_mptcp_mib_field rm_type) 657 { 658 struct mptcp_subflow_context *subflow, *tmp; 659 struct sock *sk = (struct sock *)msk; 660 u8 i; 661 662 pr_debug("%s rm_list_nr %d\n", 663 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr); 664 665 msk_owned_by_me(msk); 666 667 if (sk->sk_state == TCP_LISTEN) 668 return; 669 670 if (!rm_list->nr) 671 return; 672 673 if (list_empty(&msk->conn_list)) 674 return; 675 676 for (i = 0; i < rm_list->nr; i++) { 677 u8 rm_id = rm_list->ids[i]; 678 bool removed = false; 679 680 mptcp_for_each_subflow_safe(msk, subflow, tmp) { 681 struct sock *ssk = mptcp_subflow_tcp_sock(subflow); 682 u8 remote_id = READ_ONCE(subflow->remote_id); 683 int how = RCV_SHUTDOWN | SEND_SHUTDOWN; 684 u8 id = subflow_get_local_id(subflow); 685 686 if ((1 << inet_sk_state_load(ssk)) & 687 (TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | TCPF_CLOSING | TCPF_CLOSE)) 688 continue; 689 if (rm_type == MPTCP_MIB_RMADDR && remote_id != rm_id) 690 continue; 691 if (rm_type == MPTCP_MIB_RMSUBFLOW && id != rm_id) 692 continue; 693 694 pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u mpc_id=%u\n", 695 rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", 696 i, rm_id, id, remote_id, msk->mpc_endpoint_id); 697 spin_unlock_bh(&msk->pm.lock); 698 mptcp_subflow_shutdown(sk, ssk, how); 699 removed |= subflow->request_join; 700 701 /* the following takes care of updating the subflows counter */ 702 mptcp_close_ssk(sk, ssk, subflow); 703 spin_lock_bh(&msk->pm.lock); 704 705 if (rm_type == MPTCP_MIB_RMSUBFLOW) 706 __MPTCP_INC_STATS(sock_net(sk), rm_type); 707 } 708 709 if (rm_type == MPTCP_MIB_RMADDR) { 710 __MPTCP_INC_STATS(sock_net(sk), rm_type); 711 if (removed && mptcp_pm_is_kernel(msk)) 712 mptcp_pm_nl_rm_addr(msk, rm_id); 713 } 714 } 715 } 716 717 static void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk) 718 { 719 mptcp_pm_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR); 720 } 721 722 void mptcp_pm_rm_subflow(struct mptcp_sock *msk, 723 const struct mptcp_rm_list *rm_list) 724 { 725 mptcp_pm_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW); 726 } 727 728 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, 729 const struct mptcp_rm_list *rm_list) 730 { 731 struct mptcp_pm_data *pm = &msk->pm; 732 u8 i; 733 734 pr_debug("msk=%p remote_ids_nr=%d\n", msk, rm_list->nr); 735 736 for (i = 0; i < rm_list->nr; i++) 737 mptcp_event_addr_removed(msk, rm_list->ids[i]); 738 739 spin_lock_bh(&pm->lock); 740 if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED)) 741 pm->rm_list_rx = *rm_list; 742 else 743 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP); 744 spin_unlock_bh(&pm->lock); 745 } 746 747 void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup) 748 { 749 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 750 struct sock *sk = subflow->conn; 751 struct mptcp_sock *msk; 752 753 pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup); 754 msk = mptcp_sk(sk); 755 if (subflow->backup != bkup) 756 subflow->backup = bkup; 757 758 mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC); 759 } 760 761 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq) 762 { 763 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 764 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 765 766 pr_debug("fail_seq=%llu\n", fail_seq); 767 768 if (!READ_ONCE(msk->allow_infinite_fallback)) 769 return; 770 771 if (!subflow->fail_tout) { 772 pr_debug("send MP_FAIL response and infinite map\n"); 773 774 subflow->send_mp_fail = 1; 775 subflow->send_infinite_map = 1; 776 tcp_send_ack(sk); 777 } else { 778 pr_debug("MP_FAIL response received\n"); 779 WRITE_ONCE(subflow->fail_tout, 0); 780 } 781 } 782 783 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb, 784 unsigned int opt_size, unsigned int remaining, 785 struct mptcp_addr_info *addr, bool *echo, 786 bool *drop_other_suboptions) 787 { 788 int ret = false; 789 u8 add_addr; 790 u8 family; 791 bool port; 792 793 spin_lock_bh(&msk->pm.lock); 794 795 /* double check after the lock is acquired */ 796 if (!mptcp_pm_should_add_signal(msk)) 797 goto out_unlock; 798 799 /* always drop every other options for pure ack ADD_ADDR; this is a 800 * plain dup-ack from TCP perspective. The other MPTCP-relevant info, 801 * if any, will be carried by the 'original' TCP ack 802 */ 803 if (skb && skb_is_tcp_pure_ack(skb)) { 804 remaining += opt_size; 805 *drop_other_suboptions = true; 806 } 807 808 *echo = mptcp_pm_should_add_signal_echo(msk); 809 port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port); 810 811 family = *echo ? msk->pm.remote.family : msk->pm.local.family; 812 if (remaining < mptcp_add_addr_len(family, *echo, port)) 813 goto out_unlock; 814 815 if (*echo) { 816 *addr = msk->pm.remote; 817 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO); 818 } else { 819 *addr = msk->pm.local; 820 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL); 821 } 822 WRITE_ONCE(msk->pm.addr_signal, add_addr); 823 ret = true; 824 825 out_unlock: 826 spin_unlock_bh(&msk->pm.lock); 827 return ret; 828 } 829 830 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 831 struct mptcp_rm_list *rm_list) 832 { 833 int ret = false, len; 834 u8 rm_addr; 835 836 spin_lock_bh(&msk->pm.lock); 837 838 /* double check after the lock is acquired */ 839 if (!mptcp_pm_should_rm_signal(msk)) 840 goto out_unlock; 841 842 rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL); 843 len = mptcp_rm_addr_len(&msk->pm.rm_list_tx); 844 if (len < 0) { 845 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 846 goto out_unlock; 847 } 848 if (remaining < len) 849 goto out_unlock; 850 851 *rm_list = msk->pm.rm_list_tx; 852 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 853 ret = true; 854 855 out_unlock: 856 spin_unlock_bh(&msk->pm.lock); 857 return ret; 858 } 859 860 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 861 { 862 struct mptcp_pm_addr_entry skc_local = { 0 }; 863 struct mptcp_addr_info msk_local; 864 865 if (WARN_ON_ONCE(!msk)) 866 return -1; 867 868 /* The 0 ID mapping is defined by the first subflow, copied into the msk 869 * addr 870 */ 871 mptcp_local_address((struct sock_common *)msk, &msk_local); 872 mptcp_local_address((struct sock_common *)skc, &skc_local.addr); 873 if (mptcp_addresses_equal(&msk_local, &skc_local.addr, false)) 874 return 0; 875 876 skc_local.addr.id = 0; 877 skc_local.flags = MPTCP_PM_ADDR_FLAG_IMPLICIT; 878 879 if (mptcp_pm_is_userspace(msk)) 880 return mptcp_userspace_pm_get_local_id(msk, &skc_local); 881 return mptcp_pm_nl_get_local_id(msk, &skc_local); 882 } 883 884 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc) 885 { 886 struct mptcp_addr_info skc_local; 887 888 mptcp_local_address((struct sock_common *)skc, &skc_local); 889 890 if (mptcp_pm_is_userspace(msk)) 891 return mptcp_userspace_pm_is_backup(msk, &skc_local); 892 893 return mptcp_pm_nl_is_backup(msk, &skc_local); 894 } 895 896 static void mptcp_pm_subflows_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) 897 { 898 struct mptcp_subflow_context *iter, *subflow = mptcp_subflow_ctx(ssk); 899 struct sock *sk = (struct sock *)msk; 900 unsigned int active_max_loss_cnt; 901 struct net *net = sock_net(sk); 902 unsigned int stale_loss_cnt; 903 bool slow; 904 905 stale_loss_cnt = mptcp_stale_loss_cnt(net); 906 if (subflow->stale || !stale_loss_cnt || subflow->stale_count <= stale_loss_cnt) 907 return; 908 909 /* look for another available subflow not in loss state */ 910 active_max_loss_cnt = max_t(int, stale_loss_cnt - 1, 1); 911 mptcp_for_each_subflow(msk, iter) { 912 if (iter != subflow && mptcp_subflow_active(iter) && 913 iter->stale_count < active_max_loss_cnt) { 914 /* we have some alternatives, try to mark this subflow as idle ...*/ 915 slow = lock_sock_fast(ssk); 916 if (!tcp_rtx_and_write_queues_empty(ssk)) { 917 subflow->stale = 1; 918 __mptcp_retransmit_pending_data(sk); 919 MPTCP_INC_STATS(net, MPTCP_MIB_SUBFLOWSTALE); 920 } 921 unlock_sock_fast(ssk, slow); 922 923 /* always try to push the pending data regardless of re-injections: 924 * we can possibly use backup subflows now, and subflow selection 925 * is cheap under the msk socket lock 926 */ 927 __mptcp_push_pending(sk, 0); 928 return; 929 } 930 } 931 } 932 933 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) 934 { 935 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 936 u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp); 937 938 /* keep track of rtx periods with no progress */ 939 if (!subflow->stale_count) { 940 subflow->stale_rcv_tstamp = rcv_tstamp; 941 subflow->stale_count++; 942 } else if (subflow->stale_rcv_tstamp == rcv_tstamp) { 943 if (subflow->stale_count < U8_MAX) 944 subflow->stale_count++; 945 mptcp_pm_subflows_chk_stale(msk, ssk); 946 } else { 947 subflow->stale_count = 0; 948 mptcp_subflow_set_active(subflow); 949 } 950 } 951 952 void mptcp_pm_worker(struct mptcp_sock *msk) 953 { 954 struct mptcp_pm_data *pm = &msk->pm; 955 956 msk_owned_by_me(msk); 957 958 if (!(pm->status & MPTCP_PM_WORK_MASK)) 959 return; 960 961 spin_lock_bh(&msk->pm.lock); 962 963 pr_debug("msk=%p status=%x\n", msk, pm->status); 964 if (pm->status & BIT(MPTCP_PM_ADD_ADDR_SEND_ACK)) { 965 pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_SEND_ACK); 966 mptcp_pm_addr_send_ack(msk); 967 } 968 if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) { 969 pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED); 970 mptcp_pm_rm_addr_recv(msk); 971 } 972 __mptcp_pm_kernel_worker(msk); 973 974 spin_unlock_bh(&msk->pm.lock); 975 } 976 977 void mptcp_pm_destroy(struct mptcp_sock *msk) 978 { 979 mptcp_pm_free_anno_list(msk); 980 981 if (mptcp_pm_is_userspace(msk)) 982 mptcp_userspace_pm_free_local_addr_list(msk); 983 } 984 985 void mptcp_pm_data_reset(struct mptcp_sock *msk) 986 { 987 u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk)); 988 struct mptcp_pm_data *pm = &msk->pm; 989 990 memset(&pm->reset, 0, sizeof(pm->reset)); 991 pm->rm_list_tx.nr = 0; 992 pm->rm_list_rx.nr = 0; 993 WRITE_ONCE(pm->pm_type, pm_type); 994 995 if (pm_type == MPTCP_PM_TYPE_KERNEL) { 996 bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk); 997 998 /* pm->work_pending must be only be set to 'true' when 999 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL 1000 */ 1001 WRITE_ONCE(pm->work_pending, 1002 (!!mptcp_pm_get_local_addr_max(msk) && 1003 subflows_allowed) || 1004 !!mptcp_pm_get_add_addr_signal_max(msk)); 1005 WRITE_ONCE(pm->accept_addr, 1006 !!mptcp_pm_get_add_addr_accept_max(msk) && 1007 subflows_allowed); 1008 WRITE_ONCE(pm->accept_subflow, subflows_allowed); 1009 1010 bitmap_fill(pm->id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1); 1011 } 1012 } 1013 1014 void mptcp_pm_data_init(struct mptcp_sock *msk) 1015 { 1016 spin_lock_init(&msk->pm.lock); 1017 INIT_LIST_HEAD(&msk->pm.anno_list); 1018 INIT_LIST_HEAD(&msk->pm.userspace_pm_local_addr_list); 1019 mptcp_pm_data_reset(msk); 1020 } 1021 1022 void __init mptcp_pm_init(void) 1023 { 1024 mptcp_pm_kernel_register(); 1025 mptcp_pm_userspace_register(); 1026 mptcp_pm_nl_init(); 1027 } 1028 1029 /* Must be called with rcu read lock held */ 1030 struct mptcp_pm_ops *mptcp_pm_find(const char *name) 1031 { 1032 struct mptcp_pm_ops *pm_ops; 1033 1034 list_for_each_entry_rcu(pm_ops, &mptcp_pm_list, list) { 1035 if (!strcmp(pm_ops->name, name)) 1036 return pm_ops; 1037 } 1038 1039 return NULL; 1040 } 1041 1042 int mptcp_pm_validate(struct mptcp_pm_ops *pm_ops) 1043 { 1044 return 0; 1045 } 1046 1047 int mptcp_pm_register(struct mptcp_pm_ops *pm_ops) 1048 { 1049 int ret; 1050 1051 ret = mptcp_pm_validate(pm_ops); 1052 if (ret) 1053 return ret; 1054 1055 spin_lock(&mptcp_pm_list_lock); 1056 if (mptcp_pm_find(pm_ops->name)) { 1057 spin_unlock(&mptcp_pm_list_lock); 1058 return -EEXIST; 1059 } 1060 list_add_tail_rcu(&pm_ops->list, &mptcp_pm_list); 1061 spin_unlock(&mptcp_pm_list_lock); 1062 1063 pr_debug("%s registered\n", pm_ops->name); 1064 return 0; 1065 } 1066 1067 void mptcp_pm_unregister(struct mptcp_pm_ops *pm_ops) 1068 { 1069 /* skip unregistering the default path manager */ 1070 if (WARN_ON_ONCE(pm_ops == &mptcp_pm_kernel)) 1071 return; 1072 1073 spin_lock(&mptcp_pm_list_lock); 1074 list_del_rcu(&pm_ops->list); 1075 spin_unlock(&mptcp_pm_list_lock); 1076 } 1077 1078 /* Build string with list of available path manager values. 1079 * Similar to tcp_get_available_congestion_control() 1080 */ 1081 void mptcp_pm_get_available(char *buf, size_t maxlen) 1082 { 1083 struct mptcp_pm_ops *pm_ops; 1084 size_t offs = 0; 1085 1086 rcu_read_lock(); 1087 list_for_each_entry_rcu(pm_ops, &mptcp_pm_list, list) { 1088 offs += snprintf(buf + offs, maxlen - offs, "%s%s", 1089 offs == 0 ? "" : " ", pm_ops->name); 1090 1091 if (WARN_ON_ONCE(offs >= maxlen)) 1092 break; 1093 } 1094 rcu_read_unlock(); 1095 } 1096