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 #include "mib.h"
  19
  20 /* forward declaration */
  21 static struct genl_family mptcp_genl_family;
  22
  23 static int pm_nl_pernet_id;
  24
  25 struct mptcp_pm_addr_entry {
  26         struct list_head        list;
  27         struct mptcp_addr_info  addr;
  28         struct rcu_head         rcu;
  29 };
  30
  31 struct mptcp_pm_add_entry {
  32         struct list_head        list;
  33         struct mptcp_addr_info  addr;
  34         struct timer_list       add_timer;
  35         struct mptcp_sock       *sock;
  36         u8                      retrans_times;
  37 };
  38
  39 struct pm_nl_pernet {
  40         /* protects pernet updates */
  41         spinlock_t              lock;
  42         struct list_head        local_addr_list;
  43         unsigned int            addrs;
  44         unsigned int            add_addr_signal_max;
  45         unsigned int            add_addr_accept_max;
  46         unsigned int            local_addr_max;
  47         unsigned int            subflows_max;
  48         unsigned int            next_id;
  49 };
  50
  51 #define MPTCP_PM_ADDR_MAX       8
  52 #define ADD_ADDR_RETRANS_MAX    3
  53
  54 static bool addresses_equal(const struct mptcp_addr_info *a,
  55                             struct mptcp_addr_info *b, bool use_port)
  56 {
  57         bool addr_equals = false;
  58
  59         if (a->family != b->family)
  60                 return false;
  61
  62         if (a->family == AF_INET)
  63                 addr_equals = a->addr.s_addr == b->addr.s_addr;
  64 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  65         else
  66                 addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
  67 #endif
  68
  69         if (!addr_equals)
  70                 return false;
  71         if (!use_port)
  72                 return true;
  73
  74         return a->port == b->port;
  75 }
  76
  77 static bool address_zero(const struct mptcp_addr_info *addr)
  78 {
  79         struct mptcp_addr_info zero;
  80
  81         memset(&zero, 0, sizeof(zero));
  82         zero.family = addr->family;
  83
  84         return addresses_equal(addr, &zero, false);
  85 }
  86
  87 static void local_address(const struct sock_common *skc,
  88                           struct mptcp_addr_info *addr)
  89 {
  90         addr->port = 0;
  91         addr->family = skc->skc_family;
  92         if (addr->family == AF_INET)
  93                 addr->addr.s_addr = skc->skc_rcv_saddr;
  94 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  95         else if (addr->family == AF_INET6)
  96                 addr->addr6 = skc->skc_v6_rcv_saddr;
  97 #endif
  98 }
  99
 100 static void remote_address(const struct sock_common *skc,
 101                            struct mptcp_addr_info *addr)
 102 {
 103         addr->family = skc->skc_family;
 104         addr->port = skc->skc_dport;
 105         if (addr->family == AF_INET)
 106                 addr->addr.s_addr = skc->skc_daddr;
 107 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 108         else if (addr->family == AF_INET6)
 109                 addr->addr6 = skc->skc_v6_daddr;
 110 #endif
 111 }
 112
 113 static bool lookup_subflow_by_saddr(const struct list_head *list,
 114                                     struct mptcp_addr_info *saddr)
 115 {
 116         struct mptcp_subflow_context *subflow;
 117         struct mptcp_addr_info cur;
 118         struct sock_common *skc;
 119
 120         list_for_each_entry(subflow, list, node) {
 121                 skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 122
 123                 local_address(skc, &cur);
 124                 if (addresses_equal(&cur, saddr, false))
 125                         return true;
 126         }
 127
 128         return false;
 129 }
 130
 131 static struct mptcp_pm_addr_entry *
 132 select_local_address(const struct pm_nl_pernet *pernet,
 133                      struct mptcp_sock *msk)
 134 {
 135         struct mptcp_pm_addr_entry *entry, *ret = NULL;
 136
 137         rcu_read_lock();
 138         spin_lock_bh(&msk->join_list_lock);
 139         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 140                 if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 141                         continue;
 142
 143                 /* avoid any address already in use by subflows and
 144                  * pending join
 145                  */
 146                 if (entry->addr.family == ((struct sock *)msk)->sk_family &&
 147                     !lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
 148                     !lookup_subflow_by_saddr(&msk->join_list, &entry->addr)) {
 149                         ret = entry;
 150                         break;
 151                 }
 152         }
 153         spin_unlock_bh(&msk->join_list_lock);
 154         rcu_read_unlock();
 155         return ret;
 156 }
 157
 158 static struct mptcp_pm_addr_entry *
 159 select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos)
 160 {
 161         struct mptcp_pm_addr_entry *entry, *ret = NULL;
 162         int i = 0;
 163
 164         rcu_read_lock();
 165         /* do not keep any additional per socket state, just signal
 166          * the address list in order.
 167          * Note: removal from the local address list during the msk life-cycle
 168          * can lead to additional addresses not being announced.
 169          */
 170         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 171                 if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 172                         continue;
 173                 if (i++ == pos) {
 174                         ret = entry;
 175                         break;
 176                 }
 177         }
 178         rcu_read_unlock();
 179         return ret;
 180 }
 181
 182 static void check_work_pending(struct mptcp_sock *msk)
 183 {
 184         if (msk->pm.add_addr_signaled == msk->pm.add_addr_signal_max &&
 185             (msk->pm.local_addr_used == msk->pm.local_addr_max ||
 186              msk->pm.subflows == msk->pm.subflows_max))
 187                 WRITE_ONCE(msk->pm.work_pending, false);
 188 }
 189
 190 static struct mptcp_pm_add_entry *
 191 lookup_anno_list_by_saddr(struct mptcp_sock *msk,
 192                           struct mptcp_addr_info *addr)
 193 {
 194         struct mptcp_pm_add_entry *entry;
 195
 196         list_for_each_entry(entry, &msk->pm.anno_list, list) {
 197                 if (addresses_equal(&entry->addr, addr, false))
 198                         return entry;
 199         }
 200
 201         return NULL;
 202 }
 203
 204 static void mptcp_pm_add_timer(struct timer_list *timer)
 205 {
 206         struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
 207         struct mptcp_sock *msk = entry->sock;
 208         struct sock *sk = (struct sock *)msk;
 209
 210         pr_debug("msk=%p", msk);
 211
 212         if (!msk)
 213                 return;
 214
 215         if (inet_sk_state_load(sk) == TCP_CLOSE)
 216                 return;
 217
 218         if (!entry->addr.id)
 219                 return;
 220
 221         if (mptcp_pm_should_add_signal(msk)) {
 222                 sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 223                 goto out;
 224         }
 225
 226         spin_lock_bh(&msk->pm.lock);
 227
 228         if (!mptcp_pm_should_add_signal(msk)) {
 229                 pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
 230                 mptcp_pm_announce_addr(msk, &entry->addr, false);
 231                 entry->retrans_times++;
 232         }
 233
 234         if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
 235                 sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX);
 236
 237         spin_unlock_bh(&msk->pm.lock);
 238
 239 out:
 240         __sock_put(sk);
 241 }
 242
 243 struct mptcp_pm_add_entry *
 244 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 245                        struct mptcp_addr_info *addr)
 246 {
 247         struct mptcp_pm_add_entry *entry;
 248         struct sock *sk = (struct sock *)msk;
 249
 250         spin_lock_bh(&msk->pm.lock);
 251         entry = lookup_anno_list_by_saddr(msk, addr);
 252         if (entry)
 253                 entry->retrans_times = ADD_ADDR_RETRANS_MAX;
 254         spin_unlock_bh(&msk->pm.lock);
 255
 256         if (entry)
 257                 sk_stop_timer_sync(sk, &entry->add_timer);
 258
 259         return entry;
 260 }
 261
 262 static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 263                                      struct mptcp_pm_addr_entry *entry)
 264 {
 265         struct mptcp_pm_add_entry *add_entry = NULL;
 266         struct sock *sk = (struct sock *)msk;
 267
 268         if (lookup_anno_list_by_saddr(msk, &entry->addr))
 269                 return false;
 270
 271         add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
 272         if (!add_entry)
 273                 return false;
 274
 275         list_add(&add_entry->list, &msk->pm.anno_list);
 276
 277         add_entry->addr = entry->addr;
 278         add_entry->sock = msk;
 279         add_entry->retrans_times = 0;
 280
 281         timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
 282         sk_reset_timer(sk, &add_entry->add_timer, jiffies + TCP_RTO_MAX);
 283
 284         return true;
 285 }
 286
 287 void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 288 {
 289         struct mptcp_pm_add_entry *entry, *tmp;
 290         struct sock *sk = (struct sock *)msk;
 291         LIST_HEAD(free_list);
 292
 293         pr_debug("msk=%p", msk);
 294
 295         spin_lock_bh(&msk->pm.lock);
 296         list_splice_init(&msk->pm.anno_list, &free_list);
 297         spin_unlock_bh(&msk->pm.lock);
 298
 299         list_for_each_entry_safe(entry, tmp, &free_list, list) {
 300                 sk_stop_timer_sync(sk, &entry->add_timer);
 301                 kfree(entry);
 302         }
 303 }
 304
 305 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 306 {
 307         struct mptcp_addr_info remote = { 0 };
 308         struct sock *sk = (struct sock *)msk;
 309         struct mptcp_pm_addr_entry *local;
 310         struct pm_nl_pernet *pernet;
 311
 312         pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 313
 314         pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
 315                  msk->pm.local_addr_used, msk->pm.local_addr_max,
 316                  msk->pm.add_addr_signaled, msk->pm.add_addr_signal_max,
 317                  msk->pm.subflows, msk->pm.subflows_max);
 318
 319         /* check first for announce */
 320         if (msk->pm.add_addr_signaled < msk->pm.add_addr_signal_max) {
 321                 local = select_signal_address(pernet,
 322                                               msk->pm.add_addr_signaled);
 323
 324                 if (local) {
 325                         if (mptcp_pm_alloc_anno_list(msk, local)) {
 326                                 msk->pm.add_addr_signaled++;
 327                                 mptcp_pm_announce_addr(msk, &local->addr, false);
 328                         }
 329                 } else {
 330                         /* pick failed, avoid fourther attempts later */
 331                         msk->pm.local_addr_used = msk->pm.add_addr_signal_max;
 332                 }
 333
 334                 check_work_pending(msk);
 335         }
 336
 337         /* check if should create a new subflow */
 338         if (msk->pm.local_addr_used < msk->pm.local_addr_max &&
 339             msk->pm.subflows < msk->pm.subflows_max) {
 340                 remote_address((struct sock_common *)sk, &remote);
 341
 342                 local = select_local_address(pernet, msk);
 343                 if (local) {
 344                         msk->pm.local_addr_used++;
 345                         msk->pm.subflows++;
 346                         check_work_pending(msk);
 347                         spin_unlock_bh(&msk->pm.lock);
 348                         __mptcp_subflow_connect(sk, &local->addr, &remote);
 349                         spin_lock_bh(&msk->pm.lock);
 350                         return;
 351                 }
 352
 353                 /* lookup failed, avoid fourther attempts later */
 354                 msk->pm.local_addr_used = msk->pm.local_addr_max;
 355                 check_work_pending(msk);
 356         }
 357 }
 358
 359 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
 360 {
 361         mptcp_pm_create_subflow_or_signal_addr(msk);
 362 }
 363
 364 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
 365 {
 366         mptcp_pm_create_subflow_or_signal_addr(msk);
 367 }
 368
 369 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 370 {
 371         struct sock *sk = (struct sock *)msk;
 372         struct mptcp_addr_info remote;
 373         struct mptcp_addr_info local;
 374
 375         pr_debug("accepted %d:%d remote family %d",
 376                  msk->pm.add_addr_accepted, msk->pm.add_addr_accept_max,
 377                  msk->pm.remote.family);
 378         msk->pm.add_addr_accepted++;
 379         msk->pm.subflows++;
 380         if (msk->pm.add_addr_accepted >= msk->pm.add_addr_accept_max ||
 381             msk->pm.subflows >= msk->pm.subflows_max)
 382                 WRITE_ONCE(msk->pm.accept_addr, false);
 383
 384         /* connect to the specified remote address, using whatever
 385          * local address the routing configuration will pick.
 386          */
 387         remote = msk->pm.remote;
 388         if (!remote.port)
 389                 remote.port = sk->sk_dport;
 390         memset(&local, 0, sizeof(local));
 391         local.family = remote.family;
 392
 393         spin_unlock_bh(&msk->pm.lock);
 394         __mptcp_subflow_connect((struct sock *)msk, &local, &remote);
 395         spin_lock_bh(&msk->pm.lock);
 396
 397         mptcp_pm_announce_addr(msk, &remote, true);
 398 }
 399
 400 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 401 {
 402         struct mptcp_subflow_context *subflow, *tmp;
 403         struct sock *sk = (struct sock *)msk;
 404
 405         pr_debug("address rm_id %d", msk->pm.rm_id);
 406
 407         if (!msk->pm.rm_id)
 408                 return;
 409
 410         if (list_empty(&msk->conn_list))
 411                 return;
 412
 413         list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 414                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 415                 int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 416                 long timeout = 0;
 417
 418                 if (msk->pm.rm_id != subflow->remote_id)
 419                         continue;
 420
 421                 spin_unlock_bh(&msk->pm.lock);
 422                 mptcp_subflow_shutdown(sk, ssk, how);
 423                 __mptcp_close_ssk(sk, ssk, subflow, timeout);
 424                 spin_lock_bh(&msk->pm.lock);
 425
 426                 msk->pm.add_addr_accepted--;
 427                 msk->pm.subflows--;
 428                 WRITE_ONCE(msk->pm.accept_addr, true);
 429
 430                 __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMADDR);
 431
 432                 break;
 433         }
 434 }
 435
 436 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id)
 437 {
 438         struct mptcp_subflow_context *subflow, *tmp;
 439         struct sock *sk = (struct sock *)msk;
 440
 441         pr_debug("subflow rm_id %d", rm_id);
 442
 443         if (!rm_id)
 444                 return;
 445
 446         if (list_empty(&msk->conn_list))
 447                 return;
 448
 449         list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 450                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 451                 int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 452                 long timeout = 0;
 453
 454                 if (rm_id != subflow->local_id)
 455                         continue;
 456
 457                 spin_unlock_bh(&msk->pm.lock);
 458                 mptcp_subflow_shutdown(sk, ssk, how);
 459                 __mptcp_close_ssk(sk, ssk, subflow, timeout);
 460                 spin_lock_bh(&msk->pm.lock);
 461
 462                 msk->pm.local_addr_used--;
 463                 msk->pm.subflows--;
 464
 465                 __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
 466
 467                 break;
 468         }
 469 }
 470
 471 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 472 {
 473         return (entry->addr.flags &
 474                 (MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
 475                 MPTCP_PM_ADDR_FLAG_SIGNAL;
 476 }
 477
 478 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 479                                              struct mptcp_pm_addr_entry *entry)
 480 {
 481         struct mptcp_pm_addr_entry *cur;
 482         int ret = -EINVAL;
 483
 484         spin_lock_bh(&pernet->lock);
 485         /* to keep the code simple, don't do IDR-like allocation for address ID,
 486          * just bail when we exceed limits
 487          */
 488         if (pernet->next_id > 255)
 489                 goto out;
 490         if (pernet->addrs >= MPTCP_PM_ADDR_MAX)
 491                 goto out;
 492
 493         /* do not insert duplicate address, differentiate on port only
 494          * singled addresses
 495          */
 496         list_for_each_entry(cur, &pernet->local_addr_list, list) {
 497                 if (addresses_equal(&cur->addr, &entry->addr,
 498                                     address_use_port(entry) &&
 499                                     address_use_port(cur)))
 500                         goto out;
 501         }
 502
 503         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
 504                 pernet->add_addr_signal_max++;
 505         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
 506                 pernet->local_addr_max++;
 507
 508         entry->addr.id = pernet->next_id++;
 509         pernet->addrs++;
 510         list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
 511         ret = entry->addr.id;
 512
 513 out:
 514         spin_unlock_bh(&pernet->lock);
 515         return ret;
 516 }
 517
 518 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 519 {
 520         struct mptcp_pm_addr_entry *entry;
 521         struct mptcp_addr_info skc_local;
 522         struct mptcp_addr_info msk_local;
 523         struct pm_nl_pernet *pernet;
 524         int ret = -1;
 525
 526         if (WARN_ON_ONCE(!msk))
 527                 return -1;
 528
 529         /* The 0 ID mapping is defined by the first subflow, copied into the msk
 530          * addr
 531          */
 532         local_address((struct sock_common *)msk, &msk_local);
 533         local_address((struct sock_common *)skc, &skc_local);
 534         if (addresses_equal(&msk_local, &skc_local, false))
 535                 return 0;
 536
 537         if (address_zero(&skc_local))
 538                 return 0;
 539
 540         pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 541
 542         rcu_read_lock();
 543         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 544                 if (addresses_equal(&entry->addr, &skc_local, false)) {
 545                         ret = entry->addr.id;
 546                         break;
 547                 }
 548         }
 549         rcu_read_unlock();
 550         if (ret >= 0)
 551                 return ret;
 552
 553         /* address not found, add to local list */
 554         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 555         if (!entry)
 556                 return -ENOMEM;
 557
 558         entry->addr = skc_local;
 559         entry->addr.ifindex = 0;
 560         entry->addr.flags = 0;
 561         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 562         if (ret < 0)
 563                 kfree(entry);
 564
 565         return ret;
 566 }
 567
 568 void mptcp_pm_nl_data_init(struct mptcp_sock *msk)
 569 {
 570         struct mptcp_pm_data *pm = &msk->pm;
 571         struct pm_nl_pernet *pernet;
 572         bool subflows;
 573
 574         pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 575
 576         pm->add_addr_signal_max = READ_ONCE(pernet->add_addr_signal_max);
 577         pm->add_addr_accept_max = READ_ONCE(pernet->add_addr_accept_max);
 578         pm->local_addr_max = READ_ONCE(pernet->local_addr_max);
 579         pm->subflows_max = READ_ONCE(pernet->subflows_max);
 580         subflows = !!pm->subflows_max;
 581         WRITE_ONCE(pm->work_pending, (!!pm->local_addr_max && subflows) ||
 582                    !!pm->add_addr_signal_max);
 583         WRITE_ONCE(pm->accept_addr, !!pm->add_addr_accept_max && subflows);
 584         WRITE_ONCE(pm->accept_subflow, subflows);
 585 }
 586
 587 #define MPTCP_PM_CMD_GRP_OFFSET 0
 588
 589 static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
 590         [MPTCP_PM_CMD_GRP_OFFSET]       = { .name = MPTCP_PM_CMD_GRP_NAME, },
 591 };
 592
 593 static const struct nla_policy
 594 mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
 595         [MPTCP_PM_ADDR_ATTR_FAMILY]     = { .type       = NLA_U16,      },
 596         [MPTCP_PM_ADDR_ATTR_ID]         = { .type       = NLA_U8,       },
 597         [MPTCP_PM_ADDR_ATTR_ADDR4]      = { .type       = NLA_U32,      },
 598         [MPTCP_PM_ADDR_ATTR_ADDR6]      =
 599                 NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
 600         [MPTCP_PM_ADDR_ATTR_PORT]       = { .type       = NLA_U16       },
 601         [MPTCP_PM_ADDR_ATTR_FLAGS]      = { .type       = NLA_U32       },
 602         [MPTCP_PM_ADDR_ATTR_IF_IDX]     = { .type       = NLA_S32       },
 603 };
 604
 605 static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
 606         [MPTCP_PM_ATTR_ADDR]            =
 607                                         NLA_POLICY_NESTED(mptcp_pm_addr_policy),
 608         [MPTCP_PM_ATTR_RCV_ADD_ADDRS]   = { .type       = NLA_U32,      },
 609         [MPTCP_PM_ATTR_SUBFLOWS]        = { .type       = NLA_U32,      },
 610 };
 611
 612 static int mptcp_pm_family_to_addr(int family)
 613 {
 614 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 615         if (family == AF_INET6)
 616                 return MPTCP_PM_ADDR_ATTR_ADDR6;
 617 #endif
 618         return MPTCP_PM_ADDR_ATTR_ADDR4;
 619 }
 620
 621 static int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
 622                                bool require_family,
 623                                struct mptcp_pm_addr_entry *entry)
 624 {
 625         struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
 626         int err, addr_addr;
 627
 628         if (!attr) {
 629                 GENL_SET_ERR_MSG(info, "missing address info");
 630                 return -EINVAL;
 631         }
 632
 633         /* no validation needed - was already done via nested policy */
 634         err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
 635                                           mptcp_pm_addr_policy, info->extack);
 636         if (err)
 637                 return err;
 638
 639         memset(entry, 0, sizeof(*entry));
 640         if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
 641                 if (!require_family)
 642                         goto skip_family;
 643
 644                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 645                                     "missing family");
 646                 return -EINVAL;
 647         }
 648
 649         entry->addr.family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
 650         if (entry->addr.family != AF_INET
 651 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 652             && entry->addr.family != AF_INET6
 653 #endif
 654             ) {
 655                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 656                                     "unknown address family");
 657                 return -EINVAL;
 658         }
 659         addr_addr = mptcp_pm_family_to_addr(entry->addr.family);
 660         if (!tb[addr_addr]) {
 661                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 662                                     "missing address data");
 663                 return -EINVAL;
 664         }
 665
 666 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 667         if (entry->addr.family == AF_INET6)
 668                 entry->addr.addr6 = nla_get_in6_addr(tb[addr_addr]);
 669         else
 670 #endif
 671                 entry->addr.addr.s_addr = nla_get_in_addr(tb[addr_addr]);
 672
 673 skip_family:
 674         if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
 675                 u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
 676
 677                 entry->addr.ifindex = val;
 678         }
 679
 680         if (tb[MPTCP_PM_ADDR_ATTR_ID])
 681                 entry->addr.id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
 682
 683         if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
 684                 entry->addr.flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
 685
 686         return 0;
 687 }
 688
 689 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 690 {
 691         return net_generic(genl_info_net(info), pm_nl_pernet_id);
 692 }
 693
 694 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 695 {
 696         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 697         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 698         struct mptcp_pm_addr_entry addr, *entry;
 699         int ret;
 700
 701         ret = mptcp_pm_parse_addr(attr, info, true, &addr);
 702         if (ret < 0)
 703                 return ret;
 704
 705         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 706         if (!entry) {
 707                 GENL_SET_ERR_MSG(info, "can't allocate addr");
 708                 return -ENOMEM;
 709         }
 710
 711         *entry = addr;
 712         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 713         if (ret < 0) {
 714                 GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
 715                 kfree(entry);
 716                 return ret;
 717         }
 718
 719         return 0;
 720 }
 721
 722 static struct mptcp_pm_addr_entry *
 723 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 724 {
 725         struct mptcp_pm_addr_entry *entry;
 726
 727         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 728                 if (entry->addr.id == id)
 729                         return entry;
 730         }
 731         return NULL;
 732 }
 733
 734 static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
 735                                       struct mptcp_addr_info *addr)
 736 {
 737         struct mptcp_pm_add_entry *entry;
 738
 739         entry = mptcp_pm_del_add_timer(msk, addr);
 740         if (entry) {
 741                 list_del(&entry->list);
 742                 kfree(entry);
 743                 return true;
 744         }
 745
 746         return false;
 747 }
 748
 749 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 750                                       struct mptcp_addr_info *addr,
 751                                       bool force)
 752 {
 753         bool ret;
 754
 755         ret = remove_anno_list_by_saddr(msk, addr);
 756         if (ret || force) {
 757                 spin_lock_bh(&msk->pm.lock);
 758                 mptcp_pm_remove_addr(msk, addr->id);
 759                 spin_unlock_bh(&msk->pm.lock);
 760         }
 761         return ret;
 762 }
 763
 764 static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 765                                                    struct mptcp_addr_info *addr)
 766 {
 767         struct mptcp_sock *msk;
 768         long s_slot = 0, s_num = 0;
 769
 770         pr_debug("remove_id=%d", addr->id);
 771
 772         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
 773                 struct sock *sk = (struct sock *)msk;
 774                 bool remove_subflow;
 775
 776                 if (list_empty(&msk->conn_list)) {
 777                         mptcp_pm_remove_anno_addr(msk, addr, false);
 778                         goto next;
 779                 }
 780
 781                 lock_sock(sk);
 782                 remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
 783                 mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);
 784                 if (remove_subflow)
 785                         mptcp_pm_remove_subflow(msk, addr->id);
 786                 release_sock(sk);
 787
 788 next:
 789                 sock_put(sk);
 790                 cond_resched();
 791         }
 792
 793         return 0;
 794 }
 795
 796 static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 797 {
 798         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 799         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 800         struct mptcp_pm_addr_entry addr, *entry;
 801         int ret;
 802
 803         ret = mptcp_pm_parse_addr(attr, info, false, &addr);
 804         if (ret < 0)
 805                 return ret;
 806
 807         spin_lock_bh(&pernet->lock);
 808         entry = __lookup_addr_by_id(pernet, addr.addr.id);
 809         if (!entry) {
 810                 GENL_SET_ERR_MSG(info, "address not found");
 811                 spin_unlock_bh(&pernet->lock);
 812                 return -EINVAL;
 813         }
 814         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
 815                 pernet->add_addr_signal_max--;
 816         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
 817                 pernet->local_addr_max--;
 818
 819         pernet->addrs--;
 820         list_del_rcu(&entry->list);
 821         spin_unlock_bh(&pernet->lock);
 822
 823         mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
 824         kfree_rcu(entry, rcu);
 825
 826         return ret;
 827 }
 828
 829 static void __flush_addrs(struct pm_nl_pernet *pernet)
 830 {
 831         while (!list_empty(&pernet->local_addr_list)) {
 832                 struct mptcp_pm_addr_entry *cur;
 833
 834                 cur = list_entry(pernet->local_addr_list.next,
 835                                  struct mptcp_pm_addr_entry, list);
 836                 list_del_rcu(&cur->list);
 837                 kfree_rcu(cur, rcu);
 838         }
 839 }
 840
 841 static void __reset_counters(struct pm_nl_pernet *pernet)
 842 {
 843         pernet->add_addr_signal_max = 0;
 844         pernet->add_addr_accept_max = 0;
 845         pernet->local_addr_max = 0;
 846         pernet->addrs = 0;
 847 }
 848
 849 static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
 850 {
 851         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 852
 853         spin_lock_bh(&pernet->lock);
 854         __flush_addrs(pernet);
 855         __reset_counters(pernet);
 856         spin_unlock_bh(&pernet->lock);
 857         return 0;
 858 }
 859
 860 static int mptcp_nl_fill_addr(struct sk_buff *skb,
 861                               struct mptcp_pm_addr_entry *entry)
 862 {
 863         struct mptcp_addr_info *addr = &entry->addr;
 864         struct nlattr *attr;
 865
 866         attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
 867         if (!attr)
 868                 return -EMSGSIZE;
 869
 870         if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
 871                 goto nla_put_failure;
 872         if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
 873                 goto nla_put_failure;
 874         if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->addr.flags))
 875                 goto nla_put_failure;
 876         if (entry->addr.ifindex &&
 877             nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->addr.ifindex))
 878                 goto nla_put_failure;
 879
 880         if (addr->family == AF_INET &&
 881             nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
 882                             addr->addr.s_addr))
 883                 goto nla_put_failure;
 884 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 885         else if (addr->family == AF_INET6 &&
 886                  nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
 887                 goto nla_put_failure;
 888 #endif
 889         nla_nest_end(skb, attr);
 890         return 0;
 891
 892 nla_put_failure:
 893         nla_nest_cancel(skb, attr);
 894         return -EMSGSIZE;
 895 }
 896
 897 static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
 898 {
 899         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 900         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 901         struct mptcp_pm_addr_entry addr, *entry;
 902         struct sk_buff *msg;
 903         void *reply;
 904         int ret;
 905
 906         ret = mptcp_pm_parse_addr(attr, info, false, &addr);
 907         if (ret < 0)
 908                 return ret;
 909
 910         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 911         if (!msg)
 912                 return -ENOMEM;
 913
 914         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
 915                                   info->genlhdr->cmd);
 916         if (!reply) {
 917                 GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
 918                 ret = -EMSGSIZE;
 919                 goto fail;
 920         }
 921
 922         spin_lock_bh(&pernet->lock);
 923         entry = __lookup_addr_by_id(pernet, addr.addr.id);
 924         if (!entry) {
 925                 GENL_SET_ERR_MSG(info, "address not found");
 926                 ret = -EINVAL;
 927                 goto unlock_fail;
 928         }
 929
 930         ret = mptcp_nl_fill_addr(msg, entry);
 931         if (ret)
 932                 goto unlock_fail;
 933
 934         genlmsg_end(msg, reply);
 935         ret = genlmsg_reply(msg, info);
 936         spin_unlock_bh(&pernet->lock);
 937         return ret;
 938
 939 unlock_fail:
 940         spin_unlock_bh(&pernet->lock);
 941
 942 fail:
 943         nlmsg_free(msg);
 944         return ret;
 945 }
 946
 947 static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
 948                                    struct netlink_callback *cb)
 949 {
 950         struct net *net = sock_net(msg->sk);
 951         struct mptcp_pm_addr_entry *entry;
 952         struct pm_nl_pernet *pernet;
 953         int id = cb->args[0];
 954         void *hdr;
 955
 956         pernet = net_generic(net, pm_nl_pernet_id);
 957
 958         spin_lock_bh(&pernet->lock);
 959         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 960                 if (entry->addr.id <= id)
 961                         continue;
 962
 963                 hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
 964                                   cb->nlh->nlmsg_seq, &mptcp_genl_family,
 965                                   NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
 966                 if (!hdr)
 967                         break;
 968
 969                 if (mptcp_nl_fill_addr(msg, entry) < 0) {
 970                         genlmsg_cancel(msg, hdr);
 971                         break;
 972                 }
 973
 974                 id = entry->addr.id;
 975                 genlmsg_end(msg, hdr);
 976         }
 977         spin_unlock_bh(&pernet->lock);
 978
 979         cb->args[0] = id;
 980         return msg->len;
 981 }
 982
 983 static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
 984 {
 985         struct nlattr *attr = info->attrs[id];
 986
 987         if (!attr)
 988                 return 0;
 989
 990         *limit = nla_get_u32(attr);
 991         if (*limit > MPTCP_PM_ADDR_MAX) {
 992                 GENL_SET_ERR_MSG(info, "limit greater than maximum");
 993                 return -EINVAL;
 994         }
 995         return 0;
 996 }
 997
 998 static int
 999 mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
1000 {
1001         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1002         unsigned int rcv_addrs, subflows;
1003         int ret;
1004
1005         spin_lock_bh(&pernet->lock);
1006         rcv_addrs = pernet->add_addr_accept_max;
1007         ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
1008         if (ret)
1009                 goto unlock;
1010
1011         subflows = pernet->subflows_max;
1012         ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
1013         if (ret)
1014                 goto unlock;
1015
1016         WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
1017         WRITE_ONCE(pernet->subflows_max, subflows);
1018
1019 unlock:
1020         spin_unlock_bh(&pernet->lock);
1021         return ret;
1022 }
1023
1024 static int
1025 mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
1026 {
1027         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1028         struct sk_buff *msg;
1029         void *reply;
1030
1031         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1032         if (!msg)
1033                 return -ENOMEM;
1034
1035         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1036                                   MPTCP_PM_CMD_GET_LIMITS);
1037         if (!reply)
1038                 goto fail;
1039
1040         if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
1041                         READ_ONCE(pernet->add_addr_accept_max)))
1042                 goto fail;
1043
1044         if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
1045                         READ_ONCE(pernet->subflows_max)))
1046                 goto fail;
1047
1048         genlmsg_end(msg, reply);
1049         return genlmsg_reply(msg, info);
1050
1051 fail:
1052         GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1053         nlmsg_free(msg);
1054         return -EMSGSIZE;
1055 }
1056
1057 static const struct genl_small_ops mptcp_pm_ops[] = {
1058         {
1059                 .cmd    = MPTCP_PM_CMD_ADD_ADDR,
1060                 .doit   = mptcp_nl_cmd_add_addr,
1061                 .flags  = GENL_ADMIN_PERM,
1062         },
1063         {
1064                 .cmd    = MPTCP_PM_CMD_DEL_ADDR,
1065                 .doit   = mptcp_nl_cmd_del_addr,
1066                 .flags  = GENL_ADMIN_PERM,
1067         },
1068         {
1069                 .cmd    = MPTCP_PM_CMD_FLUSH_ADDRS,
1070                 .doit   = mptcp_nl_cmd_flush_addrs,
1071                 .flags  = GENL_ADMIN_PERM,
1072         },
1073         {
1074                 .cmd    = MPTCP_PM_CMD_GET_ADDR,
1075                 .doit   = mptcp_nl_cmd_get_addr,
1076                 .dumpit   = mptcp_nl_cmd_dump_addrs,
1077         },
1078         {
1079                 .cmd    = MPTCP_PM_CMD_SET_LIMITS,
1080                 .doit   = mptcp_nl_cmd_set_limits,
1081                 .flags  = GENL_ADMIN_PERM,
1082         },
1083         {
1084                 .cmd    = MPTCP_PM_CMD_GET_LIMITS,
1085                 .doit   = mptcp_nl_cmd_get_limits,
1086         },
1087 };
1088
1089 static struct genl_family mptcp_genl_family __ro_after_init = {
1090         .name           = MPTCP_PM_NAME,
1091         .version        = MPTCP_PM_VER,
1092         .maxattr        = MPTCP_PM_ATTR_MAX,
1093         .policy         = mptcp_pm_policy,
1094         .netnsok        = true,
1095         .module         = THIS_MODULE,
1096         .small_ops      = mptcp_pm_ops,
1097         .n_small_ops    = ARRAY_SIZE(mptcp_pm_ops),
1098         .mcgrps         = mptcp_pm_mcgrps,
1099         .n_mcgrps       = ARRAY_SIZE(mptcp_pm_mcgrps),
1100 };
1101
1102 static int __net_init pm_nl_init_net(struct net *net)
1103 {
1104         struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
1105
1106         INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
1107         __reset_counters(pernet);
1108         pernet->next_id = 1;
1109         spin_lock_init(&pernet->lock);
1110         return 0;
1111 }
1112
1113 static void __net_exit pm_nl_exit_net(struct list_head *net_list)
1114 {
1115         struct net *net;
1116
1117         list_for_each_entry(net, net_list, exit_list) {
1118                 /* net is removed from namespace list, can't race with
1119                  * other modifiers
1120                  */
1121                 __flush_addrs(net_generic(net, pm_nl_pernet_id));
1122         }
1123 }
1124
1125 static struct pernet_operations mptcp_pm_pernet_ops = {
1126         .init = pm_nl_init_net,
1127         .exit_batch = pm_nl_exit_net,
1128         .id = &pm_nl_pernet_id,
1129         .size = sizeof(struct pm_nl_pernet),
1130 };
1131
1132 void __init mptcp_pm_nl_init(void)
1133 {
1134         if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
1135                 panic("Failed to register MPTCP PM pernet subsystem.\n");
1136
1137         if (genl_register_family(&mptcp_genl_family))
1138                 panic("Failed to register MPTCP PM netlink family\n");
1139 }