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/kernel.h> 9 #include <net/tcp.h> 10 #include <net/mptcp.h> 11 #include "protocol.h" 12 13 #include "mib.h" 14 15 /* path manager command handlers */ 16 17 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 18 const struct mptcp_addr_info *addr, 19 bool echo) 20 { 21 u8 add_addr = READ_ONCE(msk->pm.addr_signal); 22 23 pr_debug("msk=%p, local_id=%d, echo=%d", msk, addr->id, echo); 24 25 lockdep_assert_held(&msk->pm.lock); 26 27 if (add_addr & 28 (echo ? BIT(MPTCP_ADD_ADDR_ECHO) : BIT(MPTCP_ADD_ADDR_SIGNAL))) { 29 MPTCP_INC_STATS(sock_net((struct sock *)msk), 30 echo ? MPTCP_MIB_ECHOADDTXDROP : MPTCP_MIB_ADDADDRTXDROP); 31 return -EINVAL; 32 } 33 34 if (echo) { 35 msk->pm.remote = *addr; 36 add_addr |= BIT(MPTCP_ADD_ADDR_ECHO); 37 } else { 38 msk->pm.local = *addr; 39 add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL); 40 } 41 WRITE_ONCE(msk->pm.addr_signal, add_addr); 42 return 0; 43 } 44 45 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list) 46 { 47 u8 rm_addr = READ_ONCE(msk->pm.addr_signal); 48 49 pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr); 50 51 if (rm_addr) { 52 MPTCP_ADD_STATS(sock_net((struct sock *)msk), 53 MPTCP_MIB_RMADDRTXDROP, rm_list->nr); 54 return -EINVAL; 55 } 56 57 msk->pm.rm_list_tx = *rm_list; 58 rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL); 59 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 60 mptcp_pm_nl_addr_send_ack(msk); 61 return 0; 62 } 63 64 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list) 65 { 66 pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr); 67 68 spin_lock_bh(&msk->pm.lock); 69 mptcp_pm_nl_rm_subflow_received(msk, rm_list); 70 spin_unlock_bh(&msk->pm.lock); 71 return 0; 72 } 73 74 /* path manager event handlers */ 75 76 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side) 77 { 78 struct mptcp_pm_data *pm = &msk->pm; 79 80 pr_debug("msk=%p, token=%u side=%d", msk, msk->token, server_side); 81 82 WRITE_ONCE(pm->server_side, server_side); 83 mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC); 84 } 85 86 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) 87 { 88 struct mptcp_pm_data *pm = &msk->pm; 89 unsigned int subflows_max; 90 int ret = 0; 91 92 if (mptcp_pm_is_userspace(msk)) { 93 if (mptcp_userspace_pm_active(msk)) { 94 spin_lock_bh(&pm->lock); 95 pm->subflows++; 96 spin_unlock_bh(&pm->lock); 97 return true; 98 } 99 return false; 100 } 101 102 subflows_max = mptcp_pm_get_subflows_max(msk); 103 104 pr_debug("msk=%p subflows=%d max=%d allow=%d", msk, pm->subflows, 105 subflows_max, READ_ONCE(pm->accept_subflow)); 106 107 /* try to avoid acquiring the lock below */ 108 if (!READ_ONCE(pm->accept_subflow)) 109 return false; 110 111 spin_lock_bh(&pm->lock); 112 if (READ_ONCE(pm->accept_subflow)) { 113 ret = pm->subflows < subflows_max; 114 if (ret && ++pm->subflows == subflows_max) 115 WRITE_ONCE(pm->accept_subflow, false); 116 } 117 spin_unlock_bh(&pm->lock); 118 119 return ret; 120 } 121 122 /* return true if the new status bit is currently cleared, that is, this event 123 * can be server, eventually by an already scheduled work 124 */ 125 static bool mptcp_pm_schedule_work(struct mptcp_sock *msk, 126 enum mptcp_pm_status new_status) 127 { 128 pr_debug("msk=%p status=%x new=%lx", msk, msk->pm.status, 129 BIT(new_status)); 130 if (msk->pm.status & BIT(new_status)) 131 return false; 132 133 msk->pm.status |= BIT(new_status); 134 mptcp_schedule_work((struct sock *)msk); 135 return true; 136 } 137 138 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk) 139 { 140 struct mptcp_pm_data *pm = &msk->pm; 141 bool announce = false; 142 143 pr_debug("msk=%p", msk); 144 145 spin_lock_bh(&pm->lock); 146 147 /* mptcp_pm_fully_established() can be invoked by multiple 148 * racing paths - accept() and check_fully_established() 149 * be sure to serve this event only once. 150 */ 151 if (READ_ONCE(pm->work_pending) && 152 !(msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED))) 153 mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED); 154 155 if ((msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0) 156 announce = true; 157 158 msk->pm.status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED); 159 spin_unlock_bh(&pm->lock); 160 161 if (announce) 162 mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, GFP_ATOMIC); 163 } 164 165 void mptcp_pm_connection_closed(struct mptcp_sock *msk) 166 { 167 pr_debug("msk=%p", msk); 168 } 169 170 void mptcp_pm_subflow_established(struct mptcp_sock *msk) 171 { 172 struct mptcp_pm_data *pm = &msk->pm; 173 174 pr_debug("msk=%p", msk); 175 176 if (!READ_ONCE(pm->work_pending)) 177 return; 178 179 spin_lock_bh(&pm->lock); 180 181 if (READ_ONCE(pm->work_pending)) 182 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 183 184 spin_unlock_bh(&pm->lock); 185 } 186 187 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk, 188 const struct mptcp_subflow_context *subflow) 189 { 190 struct mptcp_pm_data *pm = &msk->pm; 191 bool update_subflows; 192 193 update_subflows = subflow->request_join || subflow->mp_join; 194 if (mptcp_pm_is_userspace(msk)) { 195 if (update_subflows) { 196 spin_lock_bh(&pm->lock); 197 pm->subflows--; 198 spin_unlock_bh(&pm->lock); 199 } 200 return; 201 } 202 203 if (!READ_ONCE(pm->work_pending) && !update_subflows) 204 return; 205 206 spin_lock_bh(&pm->lock); 207 if (update_subflows) 208 __mptcp_pm_close_subflow(msk); 209 210 /* Even if this subflow is not really established, tell the PM to try 211 * to pick the next ones, if possible. 212 */ 213 if (mptcp_pm_nl_check_work_pending(msk)) 214 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 215 216 spin_unlock_bh(&pm->lock); 217 } 218 219 void mptcp_pm_add_addr_received(const struct sock *ssk, 220 const struct mptcp_addr_info *addr) 221 { 222 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 223 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 224 struct mptcp_pm_data *pm = &msk->pm; 225 226 pr_debug("msk=%p remote_id=%d accept=%d", msk, addr->id, 227 READ_ONCE(pm->accept_addr)); 228 229 mptcp_event_addr_announced(ssk, addr); 230 231 spin_lock_bh(&pm->lock); 232 233 if (mptcp_pm_is_userspace(msk)) { 234 if (mptcp_userspace_pm_active(msk)) { 235 mptcp_pm_announce_addr(msk, addr, true); 236 mptcp_pm_add_addr_send_ack(msk); 237 } else { 238 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 239 } 240 } else if (!READ_ONCE(pm->accept_addr)) { 241 mptcp_pm_announce_addr(msk, addr, true); 242 mptcp_pm_add_addr_send_ack(msk); 243 } else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) { 244 pm->remote = *addr; 245 } else { 246 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 247 } 248 249 spin_unlock_bh(&pm->lock); 250 } 251 252 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, 253 const struct mptcp_addr_info *addr) 254 { 255 struct mptcp_pm_data *pm = &msk->pm; 256 257 pr_debug("msk=%p", msk); 258 259 spin_lock_bh(&pm->lock); 260 261 if (mptcp_lookup_anno_list_by_saddr(msk, addr) && READ_ONCE(pm->work_pending)) 262 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 263 264 spin_unlock_bh(&pm->lock); 265 } 266 267 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk) 268 { 269 if (!mptcp_pm_should_add_signal(msk)) 270 return; 271 272 mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK); 273 } 274 275 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, 276 const struct mptcp_rm_list *rm_list) 277 { 278 struct mptcp_pm_data *pm = &msk->pm; 279 u8 i; 280 281 pr_debug("msk=%p remote_ids_nr=%d", msk, rm_list->nr); 282 283 for (i = 0; i < rm_list->nr; i++) 284 mptcp_event_addr_removed(msk, rm_list->ids[i]); 285 286 spin_lock_bh(&pm->lock); 287 if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED)) 288 pm->rm_list_rx = *rm_list; 289 else 290 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP); 291 spin_unlock_bh(&pm->lock); 292 } 293 294 void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup) 295 { 296 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 297 struct sock *sk = subflow->conn; 298 struct mptcp_sock *msk; 299 300 pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup); 301 msk = mptcp_sk(sk); 302 if (subflow->backup != bkup) 303 subflow->backup = bkup; 304 305 mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC); 306 } 307 308 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq) 309 { 310 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 311 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 312 313 pr_debug("fail_seq=%llu", fail_seq); 314 315 if (!READ_ONCE(msk->allow_infinite_fallback)) 316 return; 317 318 if (!subflow->fail_tout) { 319 pr_debug("send MP_FAIL response and infinite map"); 320 321 subflow->send_mp_fail = 1; 322 subflow->send_infinite_map = 1; 323 tcp_send_ack(sk); 324 } else { 325 pr_debug("MP_FAIL response received"); 326 WRITE_ONCE(subflow->fail_tout, 0); 327 } 328 } 329 330 /* path manager helpers */ 331 332 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb, 333 unsigned int opt_size, unsigned int remaining, 334 struct mptcp_addr_info *addr, bool *echo, 335 bool *drop_other_suboptions) 336 { 337 int ret = false; 338 u8 add_addr; 339 u8 family; 340 bool port; 341 342 spin_lock_bh(&msk->pm.lock); 343 344 /* double check after the lock is acquired */ 345 if (!mptcp_pm_should_add_signal(msk)) 346 goto out_unlock; 347 348 /* always drop every other options for pure ack ADD_ADDR; this is a 349 * plain dup-ack from TCP perspective. The other MPTCP-relevant info, 350 * if any, will be carried by the 'original' TCP ack 351 */ 352 if (skb && skb_is_tcp_pure_ack(skb)) { 353 remaining += opt_size; 354 *drop_other_suboptions = true; 355 } 356 357 *echo = mptcp_pm_should_add_signal_echo(msk); 358 port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port); 359 360 family = *echo ? msk->pm.remote.family : msk->pm.local.family; 361 if (remaining < mptcp_add_addr_len(family, *echo, port)) 362 goto out_unlock; 363 364 if (*echo) { 365 *addr = msk->pm.remote; 366 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO); 367 } else { 368 *addr = msk->pm.local; 369 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL); 370 } 371 WRITE_ONCE(msk->pm.addr_signal, add_addr); 372 ret = true; 373 374 out_unlock: 375 spin_unlock_bh(&msk->pm.lock); 376 return ret; 377 } 378 379 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 380 struct mptcp_rm_list *rm_list) 381 { 382 int ret = false, len; 383 u8 rm_addr; 384 385 spin_lock_bh(&msk->pm.lock); 386 387 /* double check after the lock is acquired */ 388 if (!mptcp_pm_should_rm_signal(msk)) 389 goto out_unlock; 390 391 rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL); 392 len = mptcp_rm_addr_len(&msk->pm.rm_list_tx); 393 if (len < 0) { 394 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 395 goto out_unlock; 396 } 397 if (remaining < len) 398 goto out_unlock; 399 400 *rm_list = msk->pm.rm_list_tx; 401 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 402 ret = true; 403 404 out_unlock: 405 spin_unlock_bh(&msk->pm.lock); 406 return ret; 407 } 408 409 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 410 { 411 struct mptcp_addr_info skc_local; 412 struct mptcp_addr_info msk_local; 413 414 if (WARN_ON_ONCE(!msk)) 415 return -1; 416 417 /* The 0 ID mapping is defined by the first subflow, copied into the msk 418 * addr 419 */ 420 mptcp_local_address((struct sock_common *)msk, &msk_local); 421 mptcp_local_address((struct sock_common *)skc, &skc_local); 422 if (mptcp_addresses_equal(&msk_local, &skc_local, false)) 423 return 0; 424 425 if (mptcp_pm_is_userspace(msk)) 426 return mptcp_userspace_pm_get_local_id(msk, &skc_local); 427 return mptcp_pm_nl_get_local_id(msk, &skc_local); 428 } 429 430 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id, 431 u8 *flags, int *ifindex) 432 { 433 *flags = 0; 434 *ifindex = 0; 435 436 if (!id) 437 return 0; 438 439 if (mptcp_pm_is_userspace(msk)) 440 return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); 441 return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); 442 } 443 444 int mptcp_pm_set_flags(struct net *net, struct nlattr *token, 445 struct mptcp_pm_addr_entry *loc, 446 struct mptcp_pm_addr_entry *rem, u8 bkup) 447 { 448 if (token) 449 return mptcp_userspace_pm_set_flags(net, token, loc, rem, bkup); 450 return mptcp_pm_nl_set_flags(net, loc, bkup); 451 } 452 453 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) 454 { 455 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 456 u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp); 457 458 /* keep track of rtx periods with no progress */ 459 if (!subflow->stale_count) { 460 subflow->stale_rcv_tstamp = rcv_tstamp; 461 subflow->stale_count++; 462 } else if (subflow->stale_rcv_tstamp == rcv_tstamp) { 463 if (subflow->stale_count < U8_MAX) 464 subflow->stale_count++; 465 mptcp_pm_nl_subflow_chk_stale(msk, ssk); 466 } else { 467 subflow->stale_count = 0; 468 mptcp_subflow_set_active(subflow); 469 } 470 } 471 472 /* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses, 473 * otherwise allow any matching local/remote pair 474 */ 475 bool mptcp_pm_addr_families_match(const struct sock *sk, 476 const struct mptcp_addr_info *loc, 477 const struct mptcp_addr_info *rem) 478 { 479 bool mptcp_is_v4 = sk->sk_family == AF_INET; 480 481 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 482 bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6); 483 bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6); 484 485 if (mptcp_is_v4) 486 return loc_is_v4 && rem_is_v4; 487 488 if (ipv6_only_sock(sk)) 489 return !loc_is_v4 && !rem_is_v4; 490 491 return loc_is_v4 == rem_is_v4; 492 #else 493 return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET; 494 #endif 495 } 496 497 void mptcp_pm_data_reset(struct mptcp_sock *msk) 498 { 499 u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk)); 500 struct mptcp_pm_data *pm = &msk->pm; 501 502 pm->add_addr_signaled = 0; 503 pm->add_addr_accepted = 0; 504 pm->local_addr_used = 0; 505 pm->subflows = 0; 506 pm->rm_list_tx.nr = 0; 507 pm->rm_list_rx.nr = 0; 508 WRITE_ONCE(pm->pm_type, pm_type); 509 510 if (pm_type == MPTCP_PM_TYPE_KERNEL) { 511 bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk); 512 513 /* pm->work_pending must be only be set to 'true' when 514 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL 515 */ 516 WRITE_ONCE(pm->work_pending, 517 (!!mptcp_pm_get_local_addr_max(msk) && 518 subflows_allowed) || 519 !!mptcp_pm_get_add_addr_signal_max(msk)); 520 WRITE_ONCE(pm->accept_addr, 521 !!mptcp_pm_get_add_addr_accept_max(msk) && 522 subflows_allowed); 523 WRITE_ONCE(pm->accept_subflow, subflows_allowed); 524 } else { 525 WRITE_ONCE(pm->work_pending, 0); 526 WRITE_ONCE(pm->accept_addr, 0); 527 WRITE_ONCE(pm->accept_subflow, 0); 528 } 529 530 WRITE_ONCE(pm->addr_signal, 0); 531 WRITE_ONCE(pm->remote_deny_join_id0, false); 532 pm->status = 0; 533 bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1); 534 } 535 536 void mptcp_pm_data_init(struct mptcp_sock *msk) 537 { 538 spin_lock_init(&msk->pm.lock); 539 INIT_LIST_HEAD(&msk->pm.anno_list); 540 INIT_LIST_HEAD(&msk->pm.userspace_pm_local_addr_list); 541 mptcp_pm_data_reset(msk); 542 } 543 544 void __init mptcp_pm_init(void) 545 { 546 mptcp_pm_nl_init(); 547 } 548