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\n", 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\n", 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 /* path manager event handlers */ 65 66 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side) 67 { 68 struct mptcp_pm_data *pm = &msk->pm; 69 70 pr_debug("msk=%p, token=%u side=%d\n", msk, msk->token, server_side); 71 72 WRITE_ONCE(pm->server_side, server_side); 73 mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC); 74 } 75 76 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk) 77 { 78 struct mptcp_pm_data *pm = &msk->pm; 79 unsigned int subflows_max; 80 int ret = 0; 81 82 if (mptcp_pm_is_userspace(msk)) { 83 if (mptcp_userspace_pm_active(msk)) { 84 spin_lock_bh(&pm->lock); 85 pm->subflows++; 86 spin_unlock_bh(&pm->lock); 87 return true; 88 } 89 return false; 90 } 91 92 subflows_max = mptcp_pm_get_subflows_max(msk); 93 94 pr_debug("msk=%p subflows=%d max=%d allow=%d\n", msk, pm->subflows, 95 subflows_max, READ_ONCE(pm->accept_subflow)); 96 97 /* try to avoid acquiring the lock below */ 98 if (!READ_ONCE(pm->accept_subflow)) 99 return false; 100 101 spin_lock_bh(&pm->lock); 102 if (READ_ONCE(pm->accept_subflow)) { 103 ret = pm->subflows < subflows_max; 104 if (ret && ++pm->subflows == subflows_max) 105 WRITE_ONCE(pm->accept_subflow, false); 106 } 107 spin_unlock_bh(&pm->lock); 108 109 return ret; 110 } 111 112 /* return true if the new status bit is currently cleared, that is, this event 113 * can be server, eventually by an already scheduled work 114 */ 115 static bool mptcp_pm_schedule_work(struct mptcp_sock *msk, 116 enum mptcp_pm_status new_status) 117 { 118 pr_debug("msk=%p status=%x new=%lx\n", msk, msk->pm.status, 119 BIT(new_status)); 120 if (msk->pm.status & BIT(new_status)) 121 return false; 122 123 msk->pm.status |= BIT(new_status); 124 mptcp_schedule_work((struct sock *)msk); 125 return true; 126 } 127 128 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk) 129 { 130 struct mptcp_pm_data *pm = &msk->pm; 131 bool announce = false; 132 133 pr_debug("msk=%p\n", msk); 134 135 spin_lock_bh(&pm->lock); 136 137 /* mptcp_pm_fully_established() can be invoked by multiple 138 * racing paths - accept() and check_fully_established() 139 * be sure to serve this event only once. 140 */ 141 if (READ_ONCE(pm->work_pending) && 142 !(msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED))) 143 mptcp_pm_schedule_work(msk, MPTCP_PM_ESTABLISHED); 144 145 if ((msk->pm.status & BIT(MPTCP_PM_ALREADY_ESTABLISHED)) == 0) 146 announce = true; 147 148 msk->pm.status |= BIT(MPTCP_PM_ALREADY_ESTABLISHED); 149 spin_unlock_bh(&pm->lock); 150 151 if (announce) 152 mptcp_event(MPTCP_EVENT_ESTABLISHED, msk, ssk, GFP_ATOMIC); 153 } 154 155 void mptcp_pm_connection_closed(struct mptcp_sock *msk) 156 { 157 pr_debug("msk=%p\n", msk); 158 } 159 160 void mptcp_pm_subflow_established(struct mptcp_sock *msk) 161 { 162 struct mptcp_pm_data *pm = &msk->pm; 163 164 pr_debug("msk=%p\n", msk); 165 166 if (!READ_ONCE(pm->work_pending)) 167 return; 168 169 spin_lock_bh(&pm->lock); 170 171 if (READ_ONCE(pm->work_pending)) 172 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 173 174 spin_unlock_bh(&pm->lock); 175 } 176 177 void mptcp_pm_subflow_check_next(struct mptcp_sock *msk, const struct sock *ssk, 178 const struct mptcp_subflow_context *subflow) 179 { 180 struct mptcp_pm_data *pm = &msk->pm; 181 bool update_subflows; 182 183 update_subflows = subflow->request_join || subflow->mp_join; 184 if (mptcp_pm_is_userspace(msk)) { 185 if (update_subflows) { 186 spin_lock_bh(&pm->lock); 187 pm->subflows--; 188 spin_unlock_bh(&pm->lock); 189 } 190 return; 191 } 192 193 if (!READ_ONCE(pm->work_pending) && !update_subflows) 194 return; 195 196 spin_lock_bh(&pm->lock); 197 if (update_subflows) 198 __mptcp_pm_close_subflow(msk); 199 200 /* Even if this subflow is not really established, tell the PM to try 201 * to pick the next ones, if possible. 202 */ 203 if (mptcp_pm_nl_check_work_pending(msk)) 204 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 205 206 spin_unlock_bh(&pm->lock); 207 } 208 209 void mptcp_pm_add_addr_received(const struct sock *ssk, 210 const struct mptcp_addr_info *addr) 211 { 212 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 213 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 214 struct mptcp_pm_data *pm = &msk->pm; 215 216 pr_debug("msk=%p remote_id=%d accept=%d\n", msk, addr->id, 217 READ_ONCE(pm->accept_addr)); 218 219 mptcp_event_addr_announced(ssk, addr); 220 221 spin_lock_bh(&pm->lock); 222 223 if (mptcp_pm_is_userspace(msk)) { 224 if (mptcp_userspace_pm_active(msk)) { 225 mptcp_pm_announce_addr(msk, addr, true); 226 mptcp_pm_add_addr_send_ack(msk); 227 } else { 228 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 229 } 230 /* id0 should not have a different address */ 231 } else if ((addr->id == 0 && !mptcp_pm_nl_is_init_remote_addr(msk, addr)) || 232 (addr->id > 0 && !READ_ONCE(pm->accept_addr))) { 233 mptcp_pm_announce_addr(msk, addr, true); 234 mptcp_pm_add_addr_send_ack(msk); 235 } else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) { 236 pm->remote = *addr; 237 } else { 238 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP); 239 } 240 241 spin_unlock_bh(&pm->lock); 242 } 243 244 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk, 245 const struct mptcp_addr_info *addr) 246 { 247 struct mptcp_pm_data *pm = &msk->pm; 248 249 pr_debug("msk=%p\n", msk); 250 251 spin_lock_bh(&pm->lock); 252 253 if (mptcp_lookup_anno_list_by_saddr(msk, addr) && READ_ONCE(pm->work_pending)) 254 mptcp_pm_schedule_work(msk, MPTCP_PM_SUBFLOW_ESTABLISHED); 255 256 spin_unlock_bh(&pm->lock); 257 } 258 259 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk) 260 { 261 if (!mptcp_pm_should_add_signal(msk)) 262 return; 263 264 mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_SEND_ACK); 265 } 266 267 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, 268 const struct mptcp_rm_list *rm_list) 269 { 270 struct mptcp_pm_data *pm = &msk->pm; 271 u8 i; 272 273 pr_debug("msk=%p remote_ids_nr=%d\n", msk, rm_list->nr); 274 275 for (i = 0; i < rm_list->nr; i++) 276 mptcp_event_addr_removed(msk, rm_list->ids[i]); 277 278 spin_lock_bh(&pm->lock); 279 if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED)) 280 pm->rm_list_rx = *rm_list; 281 else 282 __MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP); 283 spin_unlock_bh(&pm->lock); 284 } 285 286 void mptcp_pm_mp_prio_received(struct sock *ssk, u8 bkup) 287 { 288 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 289 struct sock *sk = subflow->conn; 290 struct mptcp_sock *msk; 291 292 pr_debug("subflow->backup=%d, bkup=%d\n", subflow->backup, bkup); 293 msk = mptcp_sk(sk); 294 if (subflow->backup != bkup) 295 subflow->backup = bkup; 296 297 mptcp_event(MPTCP_EVENT_SUB_PRIORITY, msk, ssk, GFP_ATOMIC); 298 } 299 300 void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq) 301 { 302 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 303 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 304 305 pr_debug("fail_seq=%llu\n", fail_seq); 306 307 if (!READ_ONCE(msk->allow_infinite_fallback)) 308 return; 309 310 if (!subflow->fail_tout) { 311 pr_debug("send MP_FAIL response and infinite map\n"); 312 313 subflow->send_mp_fail = 1; 314 subflow->send_infinite_map = 1; 315 tcp_send_ack(sk); 316 } else { 317 pr_debug("MP_FAIL response received\n"); 318 WRITE_ONCE(subflow->fail_tout, 0); 319 } 320 } 321 322 /* path manager helpers */ 323 324 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb, 325 unsigned int opt_size, unsigned int remaining, 326 struct mptcp_addr_info *addr, bool *echo, 327 bool *drop_other_suboptions) 328 { 329 int ret = false; 330 u8 add_addr; 331 u8 family; 332 bool port; 333 334 spin_lock_bh(&msk->pm.lock); 335 336 /* double check after the lock is acquired */ 337 if (!mptcp_pm_should_add_signal(msk)) 338 goto out_unlock; 339 340 /* always drop every other options for pure ack ADD_ADDR; this is a 341 * plain dup-ack from TCP perspective. The other MPTCP-relevant info, 342 * if any, will be carried by the 'original' TCP ack 343 */ 344 if (skb && skb_is_tcp_pure_ack(skb)) { 345 remaining += opt_size; 346 *drop_other_suboptions = true; 347 } 348 349 *echo = mptcp_pm_should_add_signal_echo(msk); 350 port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port); 351 352 family = *echo ? msk->pm.remote.family : msk->pm.local.family; 353 if (remaining < mptcp_add_addr_len(family, *echo, port)) 354 goto out_unlock; 355 356 if (*echo) { 357 *addr = msk->pm.remote; 358 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO); 359 } else { 360 *addr = msk->pm.local; 361 add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL); 362 } 363 WRITE_ONCE(msk->pm.addr_signal, add_addr); 364 ret = true; 365 366 out_unlock: 367 spin_unlock_bh(&msk->pm.lock); 368 return ret; 369 } 370 371 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 372 struct mptcp_rm_list *rm_list) 373 { 374 int ret = false, len; 375 u8 rm_addr; 376 377 spin_lock_bh(&msk->pm.lock); 378 379 /* double check after the lock is acquired */ 380 if (!mptcp_pm_should_rm_signal(msk)) 381 goto out_unlock; 382 383 rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL); 384 len = mptcp_rm_addr_len(&msk->pm.rm_list_tx); 385 if (len < 0) { 386 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 387 goto out_unlock; 388 } 389 if (remaining < len) 390 goto out_unlock; 391 392 *rm_list = msk->pm.rm_list_tx; 393 WRITE_ONCE(msk->pm.addr_signal, rm_addr); 394 ret = true; 395 396 out_unlock: 397 spin_unlock_bh(&msk->pm.lock); 398 return ret; 399 } 400 401 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 402 { 403 struct mptcp_addr_info skc_local; 404 struct mptcp_addr_info msk_local; 405 406 if (WARN_ON_ONCE(!msk)) 407 return -1; 408 409 /* The 0 ID mapping is defined by the first subflow, copied into the msk 410 * addr 411 */ 412 mptcp_local_address((struct sock_common *)msk, &msk_local); 413 mptcp_local_address((struct sock_common *)skc, &skc_local); 414 if (mptcp_addresses_equal(&msk_local, &skc_local, false)) 415 return 0; 416 417 if (mptcp_pm_is_userspace(msk)) 418 return mptcp_userspace_pm_get_local_id(msk, &skc_local); 419 return mptcp_pm_nl_get_local_id(msk, &skc_local); 420 } 421 422 bool mptcp_pm_is_backup(struct mptcp_sock *msk, struct sock_common *skc) 423 { 424 struct mptcp_addr_info skc_local; 425 426 mptcp_local_address((struct sock_common *)skc, &skc_local); 427 428 if (mptcp_pm_is_userspace(msk)) 429 return mptcp_userspace_pm_is_backup(msk, &skc_local); 430 431 return mptcp_pm_nl_is_backup(msk, &skc_local); 432 } 433 434 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id, 435 u8 *flags, int *ifindex) 436 { 437 *flags = 0; 438 *ifindex = 0; 439 440 if (mptcp_pm_is_userspace(msk)) 441 return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); 442 return mptcp_pm_nl_get_flags_and_ifindex_by_id(msk, id, flags, ifindex); 443 } 444 445 int mptcp_pm_set_flags(struct net *net, struct nlattr *token, 446 struct mptcp_pm_addr_entry *loc, 447 struct mptcp_pm_addr_entry *rem, u8 bkup) 448 { 449 if (token) 450 return mptcp_userspace_pm_set_flags(net, token, loc, rem, bkup); 451 return mptcp_pm_nl_set_flags(net, loc, bkup); 452 } 453 454 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk) 455 { 456 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); 457 u32 rcv_tstamp = READ_ONCE(tcp_sk(ssk)->rcv_tstamp); 458 459 /* keep track of rtx periods with no progress */ 460 if (!subflow->stale_count) { 461 subflow->stale_rcv_tstamp = rcv_tstamp; 462 subflow->stale_count++; 463 } else if (subflow->stale_rcv_tstamp == rcv_tstamp) { 464 if (subflow->stale_count < U8_MAX) 465 subflow->stale_count++; 466 mptcp_pm_nl_subflow_chk_stale(msk, ssk); 467 } else { 468 subflow->stale_count = 0; 469 mptcp_subflow_set_active(subflow); 470 } 471 } 472 473 /* if sk is ipv4 or ipv6_only allows only same-family local and remote addresses, 474 * otherwise allow any matching local/remote pair 475 */ 476 bool mptcp_pm_addr_families_match(const struct sock *sk, 477 const struct mptcp_addr_info *loc, 478 const struct mptcp_addr_info *rem) 479 { 480 bool mptcp_is_v4 = sk->sk_family == AF_INET; 481 482 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 483 bool loc_is_v4 = loc->family == AF_INET || ipv6_addr_v4mapped(&loc->addr6); 484 bool rem_is_v4 = rem->family == AF_INET || ipv6_addr_v4mapped(&rem->addr6); 485 486 if (mptcp_is_v4) 487 return loc_is_v4 && rem_is_v4; 488 489 if (ipv6_only_sock(sk)) 490 return !loc_is_v4 && !rem_is_v4; 491 492 return loc_is_v4 == rem_is_v4; 493 #else 494 return mptcp_is_v4 && loc->family == AF_INET && rem->family == AF_INET; 495 #endif 496 } 497 498 void mptcp_pm_data_reset(struct mptcp_sock *msk) 499 { 500 u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk)); 501 struct mptcp_pm_data *pm = &msk->pm; 502 503 pm->add_addr_signaled = 0; 504 pm->add_addr_accepted = 0; 505 pm->local_addr_used = 0; 506 pm->subflows = 0; 507 pm->rm_list_tx.nr = 0; 508 pm->rm_list_rx.nr = 0; 509 WRITE_ONCE(pm->pm_type, pm_type); 510 511 if (pm_type == MPTCP_PM_TYPE_KERNEL) { 512 bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk); 513 514 /* pm->work_pending must be only be set to 'true' when 515 * pm->pm_type is set to MPTCP_PM_TYPE_KERNEL 516 */ 517 WRITE_ONCE(pm->work_pending, 518 (!!mptcp_pm_get_local_addr_max(msk) && 519 subflows_allowed) || 520 !!mptcp_pm_get_add_addr_signal_max(msk)); 521 WRITE_ONCE(pm->accept_addr, 522 !!mptcp_pm_get_add_addr_accept_max(msk) && 523 subflows_allowed); 524 WRITE_ONCE(pm->accept_subflow, subflows_allowed); 525 } else { 526 WRITE_ONCE(pm->work_pending, 0); 527 WRITE_ONCE(pm->accept_addr, 0); 528 WRITE_ONCE(pm->accept_subflow, 0); 529 } 530 531 WRITE_ONCE(pm->addr_signal, 0); 532 WRITE_ONCE(pm->remote_deny_join_id0, false); 533 pm->status = 0; 534 bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1); 535 } 536 537 void mptcp_pm_data_init(struct mptcp_sock *msk) 538 { 539 spin_lock_init(&msk->pm.lock); 540 INIT_LIST_HEAD(&msk->pm.anno_list); 541 INIT_LIST_HEAD(&msk->pm.userspace_pm_local_addr_list); 542 mptcp_pm_data_reset(msk); 543 } 544 545 void __init mptcp_pm_init(void) 546 { 547 mptcp_pm_nl_init(); 548 } 549