net/mptcp/pm_netlink.c

   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 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 }