1 // SPDX-License-Identifier: GPL-2.0 2 /* Multipath TCP 3 * 4 * Copyright (c) 2020, Red Hat, Inc. 5 */ 6 7 #define pr_fmt(fmt) "MPTCP: " fmt 8 9 #include <linux/inet.h> 10 #include <linux/kernel.h> 11 #include <net/tcp.h> 12 #include <net/netns/generic.h> 13 #include <net/mptcp.h> 14 #include <net/genetlink.h> 15 #include <uapi/linux/mptcp.h> 16 17 #include "protocol.h" 18 19 /* forward declaration */ 20 static struct genl_family mptcp_genl_family; 21 22 static int pm_nl_pernet_id; 23 24 struct mptcp_pm_addr_entry { 25 struct list_head list; 26 unsigned int flags; 27 int ifindex; 28 struct mptcp_addr_info addr; 29 struct rcu_head rcu; 30 }; 31 32 struct pm_nl_pernet { 33 /* protects pernet updates */ 34 spinlock_t lock; 35 struct list_head local_addr_list; 36 unsigned int addrs; 37 unsigned int add_addr_signal_max; 38 unsigned int add_addr_accept_max; 39 unsigned int local_addr_max; 40 unsigned int subflows_max; 41 unsigned int next_id; 42 }; 43 44 #define MPTCP_PM_ADDR_MAX 8 45 46 static bool addresses_equal(const struct mptcp_addr_info *a, 47 struct mptcp_addr_info *b, bool use_port) 48 { 49 bool addr_equals = false; 50 51 if (a->family != b->family) 52 return false; 53 54 if (a->family == AF_INET) 55 addr_equals = a->addr.s_addr == b->addr.s_addr; 56 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 57 else 58 addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6); 59 #endif 60 61 if (!addr_equals) 62 return false; 63 if (!use_port) 64 return true; 65 66 return a->port == b->port; 67 } 68 69 static void local_address(const struct sock_common *skc, 70 struct mptcp_addr_info *addr) 71 { 72 addr->port = 0; 73 addr->family = skc->skc_family; 74 if (addr->family == AF_INET) 75 addr->addr.s_addr = skc->skc_rcv_saddr; 76 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 77 else if (addr->family == AF_INET6) 78 addr->addr6 = skc->skc_v6_rcv_saddr; 79 #endif 80 } 81 82 static void remote_address(const struct sock_common *skc, 83 struct mptcp_addr_info *addr) 84 { 85 addr->family = skc->skc_family; 86 addr->port = skc->skc_dport; 87 if (addr->family == AF_INET) 88 addr->addr.s_addr = skc->skc_daddr; 89 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 90 else if (addr->family == AF_INET6) 91 addr->addr6 = skc->skc_v6_daddr; 92 #endif 93 } 94 95 static bool lookup_subflow_by_saddr(const struct list_head *list, 96 struct mptcp_addr_info *saddr) 97 { 98 struct mptcp_subflow_context *subflow; 99 struct mptcp_addr_info cur; 100 struct sock_common *skc; 101 102 list_for_each_entry(subflow, list, node) { 103 skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow); 104 105 local_address(skc, &cur); 106 if (addresses_equal(&cur, saddr, false)) 107 return true; 108 } 109 110 return false; 111 } 112 113 static struct mptcp_pm_addr_entry * 114 select_local_address(const struct pm_nl_pernet *pernet, 115 struct mptcp_sock *msk) 116 { 117 struct mptcp_pm_addr_entry *entry, *ret = NULL; 118 119 rcu_read_lock(); 120 spin_lock_bh(&msk->join_list_lock); 121 list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) { 122 if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)) 123 continue; 124 125 /* avoid any address already in use by subflows and 126 * pending join 127 */ 128 if (entry->addr.family == ((struct sock *)msk)->sk_family && 129 !lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) && 130 !lookup_subflow_by_saddr(&msk->join_list, &entry->addr)) { 131 ret = entry; 132 break; 133 } 134 } 135 spin_unlock_bh(&msk->join_list_lock); 136 rcu_read_unlock(); 137 return ret; 138 } 139 140 static struct mptcp_pm_addr_entry * 141 select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos) 142 { 143 struct mptcp_pm_addr_entry *entry, *ret = NULL; 144 int i = 0; 145 146 rcu_read_lock(); 147 /* do not keep any additional per socket state, just signal 148 * the address list in order. 149 * Note: removal from the local address list during the msk life-cycle 150 * can lead to additional addresses not being announced. 151 */ 152 list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) { 153 if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) 154 continue; 155 if (i++ == pos) { 156 ret = entry; 157 break; 158 } 159 } 160 rcu_read_unlock(); 161 return ret; 162 } 163 164 static void check_work_pending(struct mptcp_sock *msk) 165 { 166 if (msk->pm.add_addr_signaled == msk->pm.add_addr_signal_max && 167 (msk->pm.local_addr_used == msk->pm.local_addr_max || 168 msk->pm.subflows == msk->pm.subflows_max)) 169 WRITE_ONCE(msk->pm.work_pending, false); 170 } 171 172 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) 173 { 174 struct sock *sk = (struct sock *)msk; 175 struct mptcp_pm_addr_entry *local; 176 struct mptcp_addr_info remote; 177 struct pm_nl_pernet *pernet; 178 179 pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id); 180 181 pr_debug("local %d:%d signal %d:%d subflows %d:%d\n", 182 msk->pm.local_addr_used, msk->pm.local_addr_max, 183 msk->pm.add_addr_signaled, msk->pm.add_addr_signal_max, 184 msk->pm.subflows, msk->pm.subflows_max); 185 186 /* check first for announce */ 187 if (msk->pm.add_addr_signaled < msk->pm.add_addr_signal_max) { 188 local = select_signal_address(pernet, 189 msk->pm.add_addr_signaled); 190 191 if (local) { 192 msk->pm.add_addr_signaled++; 193 mptcp_pm_announce_addr(msk, &local->addr); 194 } else { 195 /* pick failed, avoid fourther attempts later */ 196 msk->pm.local_addr_used = msk->pm.add_addr_signal_max; 197 } 198 199 check_work_pending(msk); 200 } 201 202 /* check if should create a new subflow */ 203 if (msk->pm.local_addr_used < msk->pm.local_addr_max && 204 msk->pm.subflows < msk->pm.subflows_max) { 205 remote_address((struct sock_common *)sk, &remote); 206 207 local = select_local_address(pernet, msk); 208 if (local) { 209 msk->pm.local_addr_used++; 210 msk->pm.subflows++; 211 check_work_pending(msk); 212 spin_unlock_bh(&msk->pm.lock); 213 __mptcp_subflow_connect(sk, local->ifindex, 214 &local->addr, &remote); 215 spin_lock_bh(&msk->pm.lock); 216 return; 217 } 218 219 /* lookup failed, avoid fourther attempts later */ 220 msk->pm.local_addr_used = msk->pm.local_addr_max; 221 check_work_pending(msk); 222 } 223 } 224 225 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk) 226 { 227 mptcp_pm_create_subflow_or_signal_addr(msk); 228 } 229 230 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk) 231 { 232 mptcp_pm_create_subflow_or_signal_addr(msk); 233 } 234 235 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk) 236 { 237 struct sock *sk = (struct sock *)msk; 238 struct mptcp_addr_info remote; 239 struct mptcp_addr_info local; 240 241 pr_debug("accepted %d:%d remote family %d", 242 msk->pm.add_addr_accepted, msk->pm.add_addr_accept_max, 243 msk->pm.remote.family); 244 msk->pm.add_addr_accepted++; 245 msk->pm.subflows++; 246 if (msk->pm.add_addr_accepted >= msk->pm.add_addr_accept_max || 247 msk->pm.subflows >= msk->pm.subflows_max) 248 WRITE_ONCE(msk->pm.accept_addr, false); 249 250 /* connect to the specified remote address, using whatever 251 * local address the routing configuration will pick. 252 */ 253 remote = msk->pm.remote; 254 if (!remote.port) 255 remote.port = sk->sk_dport; 256 memset(&local, 0, sizeof(local)); 257 local.family = remote.family; 258 259 spin_unlock_bh(&msk->pm.lock); 260 __mptcp_subflow_connect((struct sock *)msk, 0, &local, &remote); 261 spin_lock_bh(&msk->pm.lock); 262 } 263 264 static bool address_use_port(struct mptcp_pm_addr_entry *entry) 265 { 266 return (entry->flags & 267 (MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) == 268 MPTCP_PM_ADDR_FLAG_SIGNAL; 269 } 270 271 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet, 272 struct mptcp_pm_addr_entry *entry) 273 { 274 struct mptcp_pm_addr_entry *cur; 275 int ret = -EINVAL; 276 277 spin_lock_bh(&pernet->lock); 278 /* to keep the code simple, don't do IDR-like allocation for address ID, 279 * just bail when we exceed limits 280 */ 281 if (pernet->next_id > 255) 282 goto out; 283 if (pernet->addrs >= MPTCP_PM_ADDR_MAX) 284 goto out; 285 286 /* do not insert duplicate address, differentiate on port only 287 * singled addresses 288 */ 289 list_for_each_entry(cur, &pernet->local_addr_list, list) { 290 if (addresses_equal(&cur->addr, &entry->addr, 291 address_use_port(entry) && 292 address_use_port(cur))) 293 goto out; 294 } 295 296 if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) 297 pernet->add_addr_signal_max++; 298 if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) 299 pernet->local_addr_max++; 300 301 entry->addr.id = pernet->next_id++; 302 pernet->addrs++; 303 list_add_tail_rcu(&entry->list, &pernet->local_addr_list); 304 ret = entry->addr.id; 305 306 out: 307 spin_unlock_bh(&pernet->lock); 308 return ret; 309 } 310 311 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc) 312 { 313 struct mptcp_pm_addr_entry *entry; 314 struct mptcp_addr_info skc_local; 315 struct mptcp_addr_info msk_local; 316 struct pm_nl_pernet *pernet; 317 int ret = -1; 318 319 if (WARN_ON_ONCE(!msk)) 320 return -1; 321 322 /* The 0 ID mapping is defined by the first subflow, copied into the msk 323 * addr 324 */ 325 local_address((struct sock_common *)msk, &msk_local); 326 local_address((struct sock_common *)msk, &skc_local); 327 if (addresses_equal(&msk_local, &skc_local, false)) 328 return 0; 329 330 pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id); 331 332 rcu_read_lock(); 333 list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) { 334 if (addresses_equal(&entry->addr, &skc_local, false)) { 335 ret = entry->addr.id; 336 break; 337 } 338 } 339 rcu_read_unlock(); 340 if (ret >= 0) 341 return ret; 342 343 /* address not found, add to local list */ 344 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 345 if (!entry) 346 return -ENOMEM; 347 348 entry->flags = 0; 349 entry->addr = skc_local; 350 ret = mptcp_pm_nl_append_new_local_addr(pernet, entry); 351 if (ret < 0) 352 kfree(entry); 353 354 return ret; 355 } 356 357 void mptcp_pm_nl_data_init(struct mptcp_sock *msk) 358 { 359 struct mptcp_pm_data *pm = &msk->pm; 360 struct pm_nl_pernet *pernet; 361 bool subflows; 362 363 pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id); 364 365 pm->add_addr_signal_max = READ_ONCE(pernet->add_addr_signal_max); 366 pm->add_addr_accept_max = READ_ONCE(pernet->add_addr_accept_max); 367 pm->local_addr_max = READ_ONCE(pernet->local_addr_max); 368 pm->subflows_max = READ_ONCE(pernet->subflows_max); 369 subflows = !!pm->subflows_max; 370 WRITE_ONCE(pm->work_pending, (!!pm->local_addr_max && subflows) || 371 !!pm->add_addr_signal_max); 372 WRITE_ONCE(pm->accept_addr, !!pm->add_addr_accept_max && subflows); 373 WRITE_ONCE(pm->accept_subflow, subflows); 374 } 375 376 #define MPTCP_PM_CMD_GRP_OFFSET 0 377 378 static const struct genl_multicast_group mptcp_pm_mcgrps[] = { 379 [MPTCP_PM_CMD_GRP_OFFSET] = { .name = MPTCP_PM_CMD_GRP_NAME, }, 380 }; 381 382 static const struct nla_policy 383 mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = { 384 [MPTCP_PM_ADDR_ATTR_FAMILY] = { .type = NLA_U16, }, 385 [MPTCP_PM_ADDR_ATTR_ID] = { .type = NLA_U8, }, 386 [MPTCP_PM_ADDR_ATTR_ADDR4] = { .type = NLA_U32, }, 387 [MPTCP_PM_ADDR_ATTR_ADDR6] = { .type = NLA_EXACT_LEN, 388 .len = sizeof(struct in6_addr), }, 389 [MPTCP_PM_ADDR_ATTR_PORT] = { .type = NLA_U16 }, 390 [MPTCP_PM_ADDR_ATTR_FLAGS] = { .type = NLA_U32 }, 391 [MPTCP_PM_ADDR_ATTR_IF_IDX] = { .type = NLA_S32 }, 392 }; 393 394 static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = { 395 [MPTCP_PM_ATTR_ADDR] = 396 NLA_POLICY_NESTED(mptcp_pm_addr_policy), 397 [MPTCP_PM_ATTR_RCV_ADD_ADDRS] = { .type = NLA_U32, }, 398 [MPTCP_PM_ATTR_SUBFLOWS] = { .type = NLA_U32, }, 399 }; 400 401 static int mptcp_pm_family_to_addr(int family) 402 { 403 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 404 if (family == AF_INET6) 405 return MPTCP_PM_ADDR_ATTR_ADDR6; 406 #endif 407 return MPTCP_PM_ADDR_ATTR_ADDR4; 408 } 409 410 static int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info, 411 bool require_family, 412 struct mptcp_pm_addr_entry *entry) 413 { 414 struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1]; 415 int err, addr_addr; 416 417 if (!attr) { 418 GENL_SET_ERR_MSG(info, "missing address info"); 419 return -EINVAL; 420 } 421 422 /* no validation needed - was already done via nested policy */ 423 err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr, 424 mptcp_pm_addr_policy, info->extack); 425 if (err) 426 return err; 427 428 memset(entry, 0, sizeof(*entry)); 429 if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) { 430 if (!require_family) 431 goto skip_family; 432 433 NL_SET_ERR_MSG_ATTR(info->extack, attr, 434 "missing family"); 435 return -EINVAL; 436 } 437 438 entry->addr.family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]); 439 if (entry->addr.family != AF_INET 440 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 441 && entry->addr.family != AF_INET6 442 #endif 443 ) { 444 NL_SET_ERR_MSG_ATTR(info->extack, attr, 445 "unknown address family"); 446 return -EINVAL; 447 } 448 addr_addr = mptcp_pm_family_to_addr(entry->addr.family); 449 if (!tb[addr_addr]) { 450 NL_SET_ERR_MSG_ATTR(info->extack, attr, 451 "missing address data"); 452 return -EINVAL; 453 } 454 455 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 456 if (entry->addr.family == AF_INET6) 457 entry->addr.addr6 = nla_get_in6_addr(tb[addr_addr]); 458 else 459 #endif 460 entry->addr.addr.s_addr = nla_get_in_addr(tb[addr_addr]); 461 462 skip_family: 463 if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) 464 entry->ifindex = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]); 465 466 if (tb[MPTCP_PM_ADDR_ATTR_ID]) 467 entry->addr.id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]); 468 469 if (tb[MPTCP_PM_ADDR_ATTR_FLAGS]) 470 entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]); 471 472 return 0; 473 } 474 475 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info) 476 { 477 return net_generic(genl_info_net(info), pm_nl_pernet_id); 478 } 479 480 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info) 481 { 482 struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR]; 483 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 484 struct mptcp_pm_addr_entry addr, *entry; 485 int ret; 486 487 ret = mptcp_pm_parse_addr(attr, info, true, &addr); 488 if (ret < 0) 489 return ret; 490 491 entry = kmalloc(sizeof(*entry), GFP_KERNEL); 492 if (!entry) { 493 GENL_SET_ERR_MSG(info, "can't allocate addr"); 494 return -ENOMEM; 495 } 496 497 *entry = addr; 498 ret = mptcp_pm_nl_append_new_local_addr(pernet, entry); 499 if (ret < 0) { 500 GENL_SET_ERR_MSG(info, "too many addresses or duplicate one"); 501 kfree(entry); 502 return ret; 503 } 504 505 return 0; 506 } 507 508 static struct mptcp_pm_addr_entry * 509 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id) 510 { 511 struct mptcp_pm_addr_entry *entry; 512 513 list_for_each_entry(entry, &pernet->local_addr_list, list) { 514 if (entry->addr.id == id) 515 return entry; 516 } 517 return NULL; 518 } 519 520 static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) 521 { 522 struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR]; 523 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 524 struct mptcp_pm_addr_entry addr, *entry; 525 int ret; 526 527 ret = mptcp_pm_parse_addr(attr, info, false, &addr); 528 if (ret < 0) 529 return ret; 530 531 spin_lock_bh(&pernet->lock); 532 entry = __lookup_addr_by_id(pernet, addr.addr.id); 533 if (!entry) { 534 GENL_SET_ERR_MSG(info, "address not found"); 535 ret = -EINVAL; 536 goto out; 537 } 538 if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) 539 pernet->add_addr_signal_max--; 540 if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) 541 pernet->local_addr_max--; 542 543 pernet->addrs--; 544 list_del_rcu(&entry->list); 545 kfree_rcu(entry, rcu); 546 out: 547 spin_unlock_bh(&pernet->lock); 548 return ret; 549 } 550 551 static void __flush_addrs(struct pm_nl_pernet *pernet) 552 { 553 while (!list_empty(&pernet->local_addr_list)) { 554 struct mptcp_pm_addr_entry *cur; 555 556 cur = list_entry(pernet->local_addr_list.next, 557 struct mptcp_pm_addr_entry, list); 558 list_del_rcu(&cur->list); 559 kfree_rcu(cur, rcu); 560 } 561 } 562 563 static void __reset_counters(struct pm_nl_pernet *pernet) 564 { 565 pernet->add_addr_signal_max = 0; 566 pernet->add_addr_accept_max = 0; 567 pernet->local_addr_max = 0; 568 pernet->addrs = 0; 569 } 570 571 static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info) 572 { 573 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 574 575 spin_lock_bh(&pernet->lock); 576 __flush_addrs(pernet); 577 __reset_counters(pernet); 578 spin_unlock_bh(&pernet->lock); 579 return 0; 580 } 581 582 static int mptcp_nl_fill_addr(struct sk_buff *skb, 583 struct mptcp_pm_addr_entry *entry) 584 { 585 struct mptcp_addr_info *addr = &entry->addr; 586 struct nlattr *attr; 587 588 attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR); 589 if (!attr) 590 return -EMSGSIZE; 591 592 if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family)) 593 goto nla_put_failure; 594 if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id)) 595 goto nla_put_failure; 596 if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->flags)) 597 goto nla_put_failure; 598 if (entry->ifindex && 599 nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->ifindex)) 600 goto nla_put_failure; 601 602 if (addr->family == AF_INET && 603 nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4, 604 addr->addr.s_addr)) 605 goto nla_put_failure; 606 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 607 else if (addr->family == AF_INET6 && 608 nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6)) 609 goto nla_put_failure; 610 #endif 611 nla_nest_end(skb, attr); 612 return 0; 613 614 nla_put_failure: 615 nla_nest_cancel(skb, attr); 616 return -EMSGSIZE; 617 } 618 619 static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info) 620 { 621 struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR]; 622 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 623 struct mptcp_pm_addr_entry addr, *entry; 624 struct sk_buff *msg; 625 void *reply; 626 int ret; 627 628 ret = mptcp_pm_parse_addr(attr, info, false, &addr); 629 if (ret < 0) 630 return ret; 631 632 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 633 if (!msg) 634 return -ENOMEM; 635 636 reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0, 637 info->genlhdr->cmd); 638 if (!reply) { 639 GENL_SET_ERR_MSG(info, "not enough space in Netlink message"); 640 ret = -EMSGSIZE; 641 goto fail; 642 } 643 644 spin_lock_bh(&pernet->lock); 645 entry = __lookup_addr_by_id(pernet, addr.addr.id); 646 if (!entry) { 647 GENL_SET_ERR_MSG(info, "address not found"); 648 ret = -EINVAL; 649 goto unlock_fail; 650 } 651 652 ret = mptcp_nl_fill_addr(msg, entry); 653 if (ret) 654 goto unlock_fail; 655 656 genlmsg_end(msg, reply); 657 ret = genlmsg_reply(msg, info); 658 spin_unlock_bh(&pernet->lock); 659 return ret; 660 661 unlock_fail: 662 spin_unlock_bh(&pernet->lock); 663 664 fail: 665 nlmsg_free(msg); 666 return ret; 667 } 668 669 static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg, 670 struct netlink_callback *cb) 671 { 672 struct net *net = sock_net(msg->sk); 673 struct mptcp_pm_addr_entry *entry; 674 struct pm_nl_pernet *pernet; 675 int id = cb->args[0]; 676 void *hdr; 677 678 pernet = net_generic(net, pm_nl_pernet_id); 679 680 spin_lock_bh(&pernet->lock); 681 list_for_each_entry(entry, &pernet->local_addr_list, list) { 682 if (entry->addr.id <= id) 683 continue; 684 685 hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid, 686 cb->nlh->nlmsg_seq, &mptcp_genl_family, 687 NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR); 688 if (!hdr) 689 break; 690 691 if (mptcp_nl_fill_addr(msg, entry) < 0) { 692 genlmsg_cancel(msg, hdr); 693 break; 694 } 695 696 id = entry->addr.id; 697 genlmsg_end(msg, hdr); 698 } 699 spin_unlock_bh(&pernet->lock); 700 701 cb->args[0] = id; 702 return msg->len; 703 } 704 705 static int parse_limit(struct genl_info *info, int id, unsigned int *limit) 706 { 707 struct nlattr *attr = info->attrs[id]; 708 709 if (!attr) 710 return 0; 711 712 *limit = nla_get_u32(attr); 713 if (*limit > MPTCP_PM_ADDR_MAX) { 714 GENL_SET_ERR_MSG(info, "limit greater than maximum"); 715 return -EINVAL; 716 } 717 return 0; 718 } 719 720 static int 721 mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info) 722 { 723 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 724 unsigned int rcv_addrs, subflows; 725 int ret; 726 727 spin_lock_bh(&pernet->lock); 728 rcv_addrs = pernet->add_addr_accept_max; 729 ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs); 730 if (ret) 731 goto unlock; 732 733 subflows = pernet->subflows_max; 734 ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows); 735 if (ret) 736 goto unlock; 737 738 WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs); 739 WRITE_ONCE(pernet->subflows_max, subflows); 740 741 unlock: 742 spin_unlock_bh(&pernet->lock); 743 return ret; 744 } 745 746 static int 747 mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info) 748 { 749 struct pm_nl_pernet *pernet = genl_info_pm_nl(info); 750 struct sk_buff *msg; 751 void *reply; 752 753 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 754 if (!msg) 755 return -ENOMEM; 756 757 reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0, 758 MPTCP_PM_CMD_GET_LIMITS); 759 if (!reply) 760 goto fail; 761 762 if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS, 763 READ_ONCE(pernet->add_addr_accept_max))) 764 goto fail; 765 766 if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS, 767 READ_ONCE(pernet->subflows_max))) 768 goto fail; 769 770 genlmsg_end(msg, reply); 771 return genlmsg_reply(msg, info); 772 773 fail: 774 GENL_SET_ERR_MSG(info, "not enough space in Netlink message"); 775 nlmsg_free(msg); 776 return -EMSGSIZE; 777 } 778 779 static struct genl_ops mptcp_pm_ops[] = { 780 { 781 .cmd = MPTCP_PM_CMD_ADD_ADDR, 782 .doit = mptcp_nl_cmd_add_addr, 783 .flags = GENL_ADMIN_PERM, 784 }, 785 { 786 .cmd = MPTCP_PM_CMD_DEL_ADDR, 787 .doit = mptcp_nl_cmd_del_addr, 788 .flags = GENL_ADMIN_PERM, 789 }, 790 { 791 .cmd = MPTCP_PM_CMD_FLUSH_ADDRS, 792 .doit = mptcp_nl_cmd_flush_addrs, 793 .flags = GENL_ADMIN_PERM, 794 }, 795 { 796 .cmd = MPTCP_PM_CMD_GET_ADDR, 797 .doit = mptcp_nl_cmd_get_addr, 798 .dumpit = mptcp_nl_cmd_dump_addrs, 799 }, 800 { 801 .cmd = MPTCP_PM_CMD_SET_LIMITS, 802 .doit = mptcp_nl_cmd_set_limits, 803 .flags = GENL_ADMIN_PERM, 804 }, 805 { 806 .cmd = MPTCP_PM_CMD_GET_LIMITS, 807 .doit = mptcp_nl_cmd_get_limits, 808 }, 809 }; 810 811 static struct genl_family mptcp_genl_family __ro_after_init = { 812 .name = MPTCP_PM_NAME, 813 .version = MPTCP_PM_VER, 814 .maxattr = MPTCP_PM_ATTR_MAX, 815 .policy = mptcp_pm_policy, 816 .netnsok = true, 817 .module = THIS_MODULE, 818 .ops = mptcp_pm_ops, 819 .n_ops = ARRAY_SIZE(mptcp_pm_ops), 820 .mcgrps = mptcp_pm_mcgrps, 821 .n_mcgrps = ARRAY_SIZE(mptcp_pm_mcgrps), 822 }; 823 824 static int __net_init pm_nl_init_net(struct net *net) 825 { 826 struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id); 827 828 INIT_LIST_HEAD_RCU(&pernet->local_addr_list); 829 __reset_counters(pernet); 830 pernet->next_id = 1; 831 spin_lock_init(&pernet->lock); 832 return 0; 833 } 834 835 static void __net_exit pm_nl_exit_net(struct list_head *net_list) 836 { 837 struct net *net; 838 839 list_for_each_entry(net, net_list, exit_list) { 840 /* net is removed from namespace list, can't race with 841 * other modifiers 842 */ 843 __flush_addrs(net_generic(net, pm_nl_pernet_id)); 844 } 845 } 846 847 static struct pernet_operations mptcp_pm_pernet_ops = { 848 .init = pm_nl_init_net, 849 .exit_batch = pm_nl_exit_net, 850 .id = &pm_nl_pernet_id, 851 .size = sizeof(struct pm_nl_pernet), 852 }; 853 854 void __init mptcp_pm_nl_init(void) 855 { 856 if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0) 857 panic("Failed to register MPTCP PM pernet subsystem.\n"); 858 859 if (genl_register_family(&mptcp_genl_family)) 860 panic("Failed to register MPTCP PM netlink family\n"); 861 } 862