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         __mptcp_flush_join_list(msk);
 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                         ret = entry;
 149                         break;
 150                 }
 151         }
 152         rcu_read_unlock();
 153         return ret;
 154 }
 155
 156 static struct mptcp_pm_addr_entry *
 157 select_signal_address(struct pm_nl_pernet *pernet, unsigned int pos)
 158 {
 159         struct mptcp_pm_addr_entry *entry, *ret = NULL;
 160         int i = 0;
 161
 162         rcu_read_lock();
 163         /* do not keep any additional per socket state, just signal
 164          * the address list in order.
 165          * Note: removal from the local address list during the msk life-cycle
 166          * can lead to additional addresses not being announced.
 167          */
 168         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 169                 if (!(entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 170                         continue;
 171                 if (i++ == pos) {
 172                         ret = entry;
 173                         break;
 174                 }
 175         }
 176         rcu_read_unlock();
 177         return ret;
 178 }
 179
 180 static void check_work_pending(struct mptcp_sock *msk)
 181 {
 182         if (msk->pm.add_addr_signaled == msk->pm.add_addr_signal_max &&
 183             (msk->pm.local_addr_used == msk->pm.local_addr_max ||
 184              msk->pm.subflows == msk->pm.subflows_max))
 185                 WRITE_ONCE(msk->pm.work_pending, false);
 186 }
 187
 188 static struct mptcp_pm_add_entry *
 189 lookup_anno_list_by_saddr(struct mptcp_sock *msk,
 190                           struct mptcp_addr_info *addr)
 191 {
 192         struct mptcp_pm_add_entry *entry;
 193
 194         list_for_each_entry(entry, &msk->pm.anno_list, list) {
 195                 if (addresses_equal(&entry->addr, addr, false))
 196                         return entry;
 197         }
 198
 199         return NULL;
 200 }
 201
 202 static void mptcp_pm_add_timer(struct timer_list *timer)
 203 {
 204         struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
 205         struct mptcp_sock *msk = entry->sock;
 206         struct sock *sk = (struct sock *)msk;
 207
 208         pr_debug("msk=%p", msk);
 209
 210         if (!msk)
 211                 return;
 212
 213         if (inet_sk_state_load(sk) == TCP_CLOSE)
 214                 return;
 215
 216         if (!entry->addr.id)
 217                 return;
 218
 219         if (mptcp_pm_should_add_signal(msk)) {
 220                 sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 221                 goto out;
 222         }
 223
 224         spin_lock_bh(&msk->pm.lock);
 225
 226         if (!mptcp_pm_should_add_signal(msk)) {
 227                 pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
 228                 mptcp_pm_announce_addr(msk, &entry->addr, false, entry->addr.port);
 229                 mptcp_pm_add_addr_send_ack(msk);
 230                 entry->retrans_times++;
 231         }
 232
 233         if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
 234                 sk_reset_timer(sk, timer,
 235                                jiffies + mptcp_get_add_addr_timeout(sock_net(sk)));
 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         struct net *net = sock_net(sk);
 268
 269         if (lookup_anno_list_by_saddr(msk, &entry->addr))
 270                 return false;
 271
 272         add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
 273         if (!add_entry)
 274                 return false;
 275
 276         list_add(&add_entry->list, &msk->pm.anno_list);
 277
 278         add_entry->addr = entry->addr;
 279         add_entry->sock = msk;
 280         add_entry->retrans_times = 0;
 281
 282         timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
 283         sk_reset_timer(sk, &add_entry->add_timer,
 284                        jiffies + mptcp_get_add_addr_timeout(net));
 285
 286         return true;
 287 }
 288
 289 void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 290 {
 291         struct mptcp_pm_add_entry *entry, *tmp;
 292         struct sock *sk = (struct sock *)msk;
 293         LIST_HEAD(free_list);
 294
 295         pr_debug("msk=%p", msk);
 296
 297         spin_lock_bh(&msk->pm.lock);
 298         list_splice_init(&msk->pm.anno_list, &free_list);
 299         spin_unlock_bh(&msk->pm.lock);
 300
 301         list_for_each_entry_safe(entry, tmp, &free_list, list) {
 302                 sk_stop_timer_sync(sk, &entry->add_timer);
 303                 kfree(entry);
 304         }
 305 }
 306
 307 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 308 {
 309         struct mptcp_addr_info remote = { 0 };
 310         struct sock *sk = (struct sock *)msk;
 311         struct mptcp_pm_addr_entry *local;
 312         struct pm_nl_pernet *pernet;
 313
 314         pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
 315
 316         pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
 317                  msk->pm.local_addr_used, msk->pm.local_addr_max,
 318                  msk->pm.add_addr_signaled, msk->pm.add_addr_signal_max,
 319                  msk->pm.subflows, msk->pm.subflows_max);
 320
 321         /* check first for announce */
 322         if (msk->pm.add_addr_signaled < msk->pm.add_addr_signal_max) {
 323                 local = select_signal_address(pernet,
 324                                               msk->pm.add_addr_signaled);
 325
 326                 if (local) {
 327                         if (mptcp_pm_alloc_anno_list(msk, local)) {
 328                                 msk->pm.add_addr_signaled++;
 329                                 mptcp_pm_announce_addr(msk, &local->addr, false, local->addr.port);
 330                                 mptcp_pm_nl_add_addr_send_ack(msk);
 331                         }
 332                 } else {
 333                         /* pick failed, avoid fourther attempts later */
 334                         msk->pm.local_addr_used = msk->pm.add_addr_signal_max;
 335                 }
 336
 337                 check_work_pending(msk);
 338         }
 339
 340         /* check if should create a new subflow */
 341         if (msk->pm.local_addr_used < msk->pm.local_addr_max &&
 342             msk->pm.subflows < msk->pm.subflows_max) {
 343                 remote_address((struct sock_common *)sk, &remote);
 344
 345                 local = select_local_address(pernet, msk);
 346                 if (local) {
 347                         msk->pm.local_addr_used++;
 348                         msk->pm.subflows++;
 349                         check_work_pending(msk);
 350                         spin_unlock_bh(&msk->pm.lock);
 351                         __mptcp_subflow_connect(sk, &local->addr, &remote);
 352                         spin_lock_bh(&msk->pm.lock);
 353                         return;
 354                 }
 355
 356                 /* lookup failed, avoid fourther attempts later */
 357                 msk->pm.local_addr_used = msk->pm.local_addr_max;
 358                 check_work_pending(msk);
 359         }
 360 }
 361
 362 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
 363 {
 364         mptcp_pm_create_subflow_or_signal_addr(msk);
 365 }
 366
 367 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
 368 {
 369         mptcp_pm_create_subflow_or_signal_addr(msk);
 370 }
 371
 372 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 373 {
 374         struct sock *sk = (struct sock *)msk;
 375         struct mptcp_addr_info remote;
 376         struct mptcp_addr_info local;
 377         bool use_port = false;
 378
 379         pr_debug("accepted %d:%d remote family %d",
 380                  msk->pm.add_addr_accepted, msk->pm.add_addr_accept_max,
 381                  msk->pm.remote.family);
 382         msk->pm.add_addr_accepted++;
 383         msk->pm.subflows++;
 384         if (msk->pm.add_addr_accepted >= msk->pm.add_addr_accept_max ||
 385             msk->pm.subflows >= msk->pm.subflows_max)
 386                 WRITE_ONCE(msk->pm.accept_addr, false);
 387
 388         /* connect to the specified remote address, using whatever
 389          * local address the routing configuration will pick.
 390          */
 391         remote = msk->pm.remote;
 392         if (!remote.port)
 393                 remote.port = sk->sk_dport;
 394         else
 395                 use_port = true;
 396         memset(&local, 0, sizeof(local));
 397         local.family = remote.family;
 398
 399         spin_unlock_bh(&msk->pm.lock);
 400         __mptcp_subflow_connect(sk, &local, &remote);
 401         spin_lock_bh(&msk->pm.lock);
 402
 403         mptcp_pm_announce_addr(msk, &remote, true, use_port);
 404         mptcp_pm_nl_add_addr_send_ack(msk);
 405 }
 406
 407 void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk)
 408 {
 409         struct mptcp_subflow_context *subflow;
 410
 411         if (!mptcp_pm_should_add_signal_ipv6(msk) &&
 412             !mptcp_pm_should_add_signal_port(msk))
 413                 return;
 414
 415         __mptcp_flush_join_list(msk);
 416         subflow = list_first_entry_or_null(&msk->conn_list, typeof(*subflow), node);
 417         if (subflow) {
 418                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 419                 u8 add_addr;
 420
 421                 spin_unlock_bh(&msk->pm.lock);
 422                 if (mptcp_pm_should_add_signal_ipv6(msk))
 423                         pr_debug("send ack for add_addr6");
 424                 if (mptcp_pm_should_add_signal_port(msk))
 425                         pr_debug("send ack for add_addr_port");
 426
 427                 lock_sock(ssk);
 428                 tcp_send_ack(ssk);
 429                 release_sock(ssk);
 430                 spin_lock_bh(&msk->pm.lock);
 431
 432                 add_addr = READ_ONCE(msk->pm.addr_signal);
 433                 if (mptcp_pm_should_add_signal_ipv6(msk))
 434                         add_addr &= ~BIT(MPTCP_ADD_ADDR_IPV6);
 435                 if (mptcp_pm_should_add_signal_port(msk))
 436                         add_addr &= ~BIT(MPTCP_ADD_ADDR_PORT);
 437                 WRITE_ONCE(msk->pm.addr_signal, add_addr);
 438         }
 439 }
 440
 441 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 442 {
 443         struct mptcp_subflow_context *subflow, *tmp;
 444         struct sock *sk = (struct sock *)msk;
 445
 446         pr_debug("address rm_id %d", msk->pm.rm_id);
 447
 448         if (!msk->pm.rm_id)
 449                 return;
 450
 451         if (list_empty(&msk->conn_list))
 452                 return;
 453
 454         list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 455                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 456                 int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 457
 458                 if (msk->pm.rm_id != subflow->remote_id)
 459                         continue;
 460
 461                 spin_unlock_bh(&msk->pm.lock);
 462                 mptcp_subflow_shutdown(sk, ssk, how);
 463                 __mptcp_close_ssk(sk, ssk, subflow);
 464                 spin_lock_bh(&msk->pm.lock);
 465
 466                 msk->pm.add_addr_accepted--;
 467                 msk->pm.subflows--;
 468                 WRITE_ONCE(msk->pm.accept_addr, true);
 469
 470                 __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMADDR);
 471
 472                 break;
 473         }
 474 }
 475
 476 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id)
 477 {
 478         struct mptcp_subflow_context *subflow, *tmp;
 479         struct sock *sk = (struct sock *)msk;
 480
 481         pr_debug("subflow rm_id %d", rm_id);
 482
 483         if (!rm_id)
 484                 return;
 485
 486         if (list_empty(&msk->conn_list))
 487                 return;
 488
 489         list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 490                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 491                 int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 492
 493                 if (rm_id != subflow->local_id)
 494                         continue;
 495
 496                 spin_unlock_bh(&msk->pm.lock);
 497                 mptcp_subflow_shutdown(sk, ssk, how);
 498                 __mptcp_close_ssk(sk, ssk, subflow);
 499                 spin_lock_bh(&msk->pm.lock);
 500
 501                 msk->pm.local_addr_used--;
 502                 msk->pm.subflows--;
 503
 504                 __MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
 505
 506                 break;
 507         }
 508 }
 509
 510 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 511 {
 512         return (entry->addr.flags &
 513                 (MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
 514                 MPTCP_PM_ADDR_FLAG_SIGNAL;
 515 }
 516
 517 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 518                                              struct mptcp_pm_addr_entry *entry)
 519 {
 520         struct mptcp_pm_addr_entry *cur;
 521         int ret = -EINVAL;
 522
 523         spin_lock_bh(&pernet->lock);
 524         /* to keep the code simple, don't do IDR-like allocation for address ID,
 525          * just bail when we exceed limits
 526          */
 527         if (pernet->next_id > 255)
 528                 goto out;
 529         if (pernet->addrs >= MPTCP_PM_ADDR_MAX)
 530                 goto out;
 531
 532         /* do not insert duplicate address, differentiate on port only
 533          * singled addresses
 534          */
 535         list_for_each_entry(cur, &pernet->local_addr_list, list) {
 536                 if (addresses_equal(&cur->addr, &entry->addr,
 537                                     address_use_port(entry) &&
 538                                     address_use_port(cur)))
 539                         goto out;
 540         }
 541
 542         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
 543                 pernet->add_addr_signal_max++;
 544         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
 545                 pernet->local_addr_max++;
 546
 547         entry->addr.id = pernet->next_id++;
 548         pernet->addrs++;
 549         list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
 550         ret = entry->addr.id;
 551
 552 out:
 553         spin_unlock_bh(&pernet->lock);
 554         return ret;
 555 }
 556
 557 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 558 {
 559         struct mptcp_pm_addr_entry *entry;
 560         struct mptcp_addr_info skc_local;
 561         struct mptcp_addr_info msk_local;
 562         struct pm_nl_pernet *pernet;
 563         int ret = -1;
 564
 565         if (WARN_ON_ONCE(!msk))
 566                 return -1;
 567
 568         /* The 0 ID mapping is defined by the first subflow, copied into the msk
 569          * addr
 570          */
 571         local_address((struct sock_common *)msk, &msk_local);
 572         local_address((struct sock_common *)skc, &skc_local);
 573         if (addresses_equal(&msk_local, &skc_local, false))
 574                 return 0;
 575
 576         if (address_zero(&skc_local))
 577                 return 0;
 578
 579         pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 580
 581         rcu_read_lock();
 582         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 583                 if (addresses_equal(&entry->addr, &skc_local, false)) {
 584                         ret = entry->addr.id;
 585                         break;
 586                 }
 587         }
 588         rcu_read_unlock();
 589         if (ret >= 0)
 590                 return ret;
 591
 592         /* address not found, add to local list */
 593         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 594         if (!entry)
 595                 return -ENOMEM;
 596
 597         entry->addr = skc_local;
 598         entry->addr.ifindex = 0;
 599         entry->addr.flags = 0;
 600         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 601         if (ret < 0)
 602                 kfree(entry);
 603
 604         return ret;
 605 }
 606
 607 void mptcp_pm_nl_data_init(struct mptcp_sock *msk)
 608 {
 609         struct mptcp_pm_data *pm = &msk->pm;
 610         struct pm_nl_pernet *pernet;
 611         bool subflows;
 612
 613         pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 614
 615         pm->add_addr_signal_max = READ_ONCE(pernet->add_addr_signal_max);
 616         pm->add_addr_accept_max = READ_ONCE(pernet->add_addr_accept_max);
 617         pm->local_addr_max = READ_ONCE(pernet->local_addr_max);
 618         pm->subflows_max = READ_ONCE(pernet->subflows_max);
 619         subflows = !!pm->subflows_max;
 620         WRITE_ONCE(pm->work_pending, (!!pm->local_addr_max && subflows) ||
 621                    !!pm->add_addr_signal_max);
 622         WRITE_ONCE(pm->accept_addr, !!pm->add_addr_accept_max && subflows);
 623         WRITE_ONCE(pm->accept_subflow, subflows);
 624 }
 625
 626 #define MPTCP_PM_CMD_GRP_OFFSET 0
 627
 628 static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
 629         [MPTCP_PM_CMD_GRP_OFFSET]       = { .name = MPTCP_PM_CMD_GRP_NAME, },
 630 };
 631
 632 static const struct nla_policy
 633 mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
 634         [MPTCP_PM_ADDR_ATTR_FAMILY]     = { .type       = NLA_U16,      },
 635         [MPTCP_PM_ADDR_ATTR_ID]         = { .type       = NLA_U8,       },
 636         [MPTCP_PM_ADDR_ATTR_ADDR4]      = { .type       = NLA_U32,      },
 637         [MPTCP_PM_ADDR_ATTR_ADDR6]      =
 638                 NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
 639         [MPTCP_PM_ADDR_ATTR_PORT]       = { .type       = NLA_U16       },
 640         [MPTCP_PM_ADDR_ATTR_FLAGS]      = { .type       = NLA_U32       },
 641         [MPTCP_PM_ADDR_ATTR_IF_IDX]     = { .type       = NLA_S32       },
 642 };
 643
 644 static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
 645         [MPTCP_PM_ATTR_ADDR]            =
 646                                         NLA_POLICY_NESTED(mptcp_pm_addr_policy),
 647         [MPTCP_PM_ATTR_RCV_ADD_ADDRS]   = { .type       = NLA_U32,      },
 648         [MPTCP_PM_ATTR_SUBFLOWS]        = { .type       = NLA_U32,      },
 649 };
 650
 651 static int mptcp_pm_family_to_addr(int family)
 652 {
 653 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 654         if (family == AF_INET6)
 655                 return MPTCP_PM_ADDR_ATTR_ADDR6;
 656 #endif
 657         return MPTCP_PM_ADDR_ATTR_ADDR4;
 658 }
 659
 660 static int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
 661                                bool require_family,
 662                                struct mptcp_pm_addr_entry *entry)
 663 {
 664         struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
 665         int err, addr_addr;
 666
 667         if (!attr) {
 668                 GENL_SET_ERR_MSG(info, "missing address info");
 669                 return -EINVAL;
 670         }
 671
 672         /* no validation needed - was already done via nested policy */
 673         err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
 674                                           mptcp_pm_addr_policy, info->extack);
 675         if (err)
 676                 return err;
 677
 678         memset(entry, 0, sizeof(*entry));
 679         if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
 680                 if (!require_family)
 681                         goto skip_family;
 682
 683                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 684                                     "missing family");
 685                 return -EINVAL;
 686         }
 687
 688         entry->addr.family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
 689         if (entry->addr.family != AF_INET
 690 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 691             && entry->addr.family != AF_INET6
 692 #endif
 693             ) {
 694                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 695                                     "unknown address family");
 696                 return -EINVAL;
 697         }
 698         addr_addr = mptcp_pm_family_to_addr(entry->addr.family);
 699         if (!tb[addr_addr]) {
 700                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
 701                                     "missing address data");
 702                 return -EINVAL;
 703         }
 704
 705 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 706         if (entry->addr.family == AF_INET6)
 707                 entry->addr.addr6 = nla_get_in6_addr(tb[addr_addr]);
 708         else
 709 #endif
 710                 entry->addr.addr.s_addr = nla_get_in_addr(tb[addr_addr]);
 711
 712 skip_family:
 713         if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
 714                 u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
 715
 716                 entry->addr.ifindex = val;
 717         }
 718
 719         if (tb[MPTCP_PM_ADDR_ATTR_ID])
 720                 entry->addr.id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
 721
 722         if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
 723                 entry->addr.flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
 724
 725         return 0;
 726 }
 727
 728 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 729 {
 730         return net_generic(genl_info_net(info), pm_nl_pernet_id);
 731 }
 732
 733 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
 734 {
 735         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 736         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 737         struct mptcp_pm_addr_entry addr, *entry;
 738         int ret;
 739
 740         ret = mptcp_pm_parse_addr(attr, info, true, &addr);
 741         if (ret < 0)
 742                 return ret;
 743
 744         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 745         if (!entry) {
 746                 GENL_SET_ERR_MSG(info, "can't allocate addr");
 747                 return -ENOMEM;
 748         }
 749
 750         *entry = addr;
 751         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
 752         if (ret < 0) {
 753                 GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
 754                 kfree(entry);
 755                 return ret;
 756         }
 757
 758         return 0;
 759 }
 760
 761 static struct mptcp_pm_addr_entry *
 762 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 763 {
 764         struct mptcp_pm_addr_entry *entry;
 765
 766         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 767                 if (entry->addr.id == id)
 768                         return entry;
 769         }
 770         return NULL;
 771 }
 772
 773 static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
 774                                       struct mptcp_addr_info *addr)
 775 {
 776         struct mptcp_pm_add_entry *entry;
 777
 778         entry = mptcp_pm_del_add_timer(msk, addr);
 779         if (entry) {
 780                 list_del(&entry->list);
 781                 kfree(entry);
 782                 return true;
 783         }
 784
 785         return false;
 786 }
 787
 788 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 789                                       struct mptcp_addr_info *addr,
 790                                       bool force)
 791 {
 792         bool ret;
 793
 794         ret = remove_anno_list_by_saddr(msk, addr);
 795         if (ret || force) {
 796                 spin_lock_bh(&msk->pm.lock);
 797                 mptcp_pm_remove_addr(msk, addr->id);
 798                 spin_unlock_bh(&msk->pm.lock);
 799         }
 800         return ret;
 801 }
 802
 803 static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 804                                                    struct mptcp_addr_info *addr)
 805 {
 806         struct mptcp_sock *msk;
 807         long s_slot = 0, s_num = 0;
 808
 809         pr_debug("remove_id=%d", addr->id);
 810
 811         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
 812                 struct sock *sk = (struct sock *)msk;
 813                 bool remove_subflow;
 814
 815                 if (list_empty(&msk->conn_list)) {
 816                         mptcp_pm_remove_anno_addr(msk, addr, false);
 817                         goto next;
 818                 }
 819
 820                 lock_sock(sk);
 821                 remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
 822                 mptcp_pm_remove_anno_addr(msk, addr, remove_subflow);
 823                 if (remove_subflow)
 824                         mptcp_pm_remove_subflow(msk, addr->id);
 825                 release_sock(sk);
 826
 827 next:
 828                 sock_put(sk);
 829                 cond_resched();
 830         }
 831
 832         return 0;
 833 }
 834
 835 static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
 836 {
 837         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 838         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 839         struct mptcp_pm_addr_entry addr, *entry;
 840         int ret;
 841
 842         ret = mptcp_pm_parse_addr(attr, info, false, &addr);
 843         if (ret < 0)
 844                 return ret;
 845
 846         spin_lock_bh(&pernet->lock);
 847         entry = __lookup_addr_by_id(pernet, addr.addr.id);
 848         if (!entry) {
 849                 GENL_SET_ERR_MSG(info, "address not found");
 850                 spin_unlock_bh(&pernet->lock);
 851                 return -EINVAL;
 852         }
 853         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)
 854                 pernet->add_addr_signal_max--;
 855         if (entry->addr.flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
 856                 pernet->local_addr_max--;
 857
 858         pernet->addrs--;
 859         list_del_rcu(&entry->list);
 860         spin_unlock_bh(&pernet->lock);
 861
 862         mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr);
 863         kfree_rcu(entry, rcu);
 864
 865         return ret;
 866 }
 867
 868 static void __flush_addrs(struct net *net, struct list_head *list)
 869 {
 870         while (!list_empty(list)) {
 871                 struct mptcp_pm_addr_entry *cur;
 872
 873                 cur = list_entry(list->next,
 874                                  struct mptcp_pm_addr_entry, list);
 875                 mptcp_nl_remove_subflow_and_signal_addr(net, &cur->addr);
 876                 list_del_rcu(&cur->list);
 877                 kfree_rcu(cur, rcu);
 878         }
 879 }
 880
 881 static void __reset_counters(struct pm_nl_pernet *pernet)
 882 {
 883         pernet->add_addr_signal_max = 0;
 884         pernet->add_addr_accept_max = 0;
 885         pernet->local_addr_max = 0;
 886         pernet->addrs = 0;
 887 }
 888
 889 static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
 890 {
 891         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 892         LIST_HEAD(free_list);
 893
 894         spin_lock_bh(&pernet->lock);
 895         list_splice_init(&pernet->local_addr_list, &free_list);
 896         __reset_counters(pernet);
 897         spin_unlock_bh(&pernet->lock);
 898         __flush_addrs(sock_net(skb->sk), &free_list);
 899         return 0;
 900 }
 901
 902 static int mptcp_nl_fill_addr(struct sk_buff *skb,
 903                               struct mptcp_pm_addr_entry *entry)
 904 {
 905         struct mptcp_addr_info *addr = &entry->addr;
 906         struct nlattr *attr;
 907
 908         attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
 909         if (!attr)
 910                 return -EMSGSIZE;
 911
 912         if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
 913                 goto nla_put_failure;
 914         if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
 915                 goto nla_put_failure;
 916         if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->addr.flags))
 917                 goto nla_put_failure;
 918         if (entry->addr.ifindex &&
 919             nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->addr.ifindex))
 920                 goto nla_put_failure;
 921
 922         if (addr->family == AF_INET &&
 923             nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
 924                             addr->addr.s_addr))
 925                 goto nla_put_failure;
 926 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 927         else if (addr->family == AF_INET6 &&
 928                  nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
 929                 goto nla_put_failure;
 930 #endif
 931         nla_nest_end(skb, attr);
 932         return 0;
 933
 934 nla_put_failure:
 935         nla_nest_cancel(skb, attr);
 936         return -EMSGSIZE;
 937 }
 938
 939 static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
 940 {
 941         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 942         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
 943         struct mptcp_pm_addr_entry addr, *entry;
 944         struct sk_buff *msg;
 945         void *reply;
 946         int ret;
 947
 948         ret = mptcp_pm_parse_addr(attr, info, false, &addr);
 949         if (ret < 0)
 950                 return ret;
 951
 952         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 953         if (!msg)
 954                 return -ENOMEM;
 955
 956         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
 957                                   info->genlhdr->cmd);
 958         if (!reply) {
 959                 GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
 960                 ret = -EMSGSIZE;
 961                 goto fail;
 962         }
 963
 964         spin_lock_bh(&pernet->lock);
 965         entry = __lookup_addr_by_id(pernet, addr.addr.id);
 966         if (!entry) {
 967                 GENL_SET_ERR_MSG(info, "address not found");
 968                 ret = -EINVAL;
 969                 goto unlock_fail;
 970         }
 971
 972         ret = mptcp_nl_fill_addr(msg, entry);
 973         if (ret)
 974                 goto unlock_fail;
 975
 976         genlmsg_end(msg, reply);
 977         ret = genlmsg_reply(msg, info);
 978         spin_unlock_bh(&pernet->lock);
 979         return ret;
 980
 981 unlock_fail:
 982         spin_unlock_bh(&pernet->lock);
 983
 984 fail:
 985         nlmsg_free(msg);
 986         return ret;
 987 }
 988
 989 static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
 990                                    struct netlink_callback *cb)
 991 {
 992         struct net *net = sock_net(msg->sk);
 993         struct mptcp_pm_addr_entry *entry;
 994         struct pm_nl_pernet *pernet;
 995         int id = cb->args[0];
 996         void *hdr;
 997
 998         pernet = net_generic(net, pm_nl_pernet_id);
 999
1000         spin_lock_bh(&pernet->lock);
1001         list_for_each_entry(entry, &pernet->local_addr_list, list) {
1002                 if (entry->addr.id <= id)
1003                         continue;
1004
1005                 hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
1006                                   cb->nlh->nlmsg_seq, &mptcp_genl_family,
1007                                   NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
1008                 if (!hdr)
1009                         break;
1010
1011                 if (mptcp_nl_fill_addr(msg, entry) < 0) {
1012                         genlmsg_cancel(msg, hdr);
1013                         break;
1014                 }
1015
1016                 id = entry->addr.id;
1017                 genlmsg_end(msg, hdr);
1018         }
1019         spin_unlock_bh(&pernet->lock);
1020
1021         cb->args[0] = id;
1022         return msg->len;
1023 }
1024
1025 static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
1026 {
1027         struct nlattr *attr = info->attrs[id];
1028
1029         if (!attr)
1030                 return 0;
1031
1032         *limit = nla_get_u32(attr);
1033         if (*limit > MPTCP_PM_ADDR_MAX) {
1034                 GENL_SET_ERR_MSG(info, "limit greater than maximum");
1035                 return -EINVAL;
1036         }
1037         return 0;
1038 }
1039
1040 static int
1041 mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
1042 {
1043         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1044         unsigned int rcv_addrs, subflows;
1045         int ret;
1046
1047         spin_lock_bh(&pernet->lock);
1048         rcv_addrs = pernet->add_addr_accept_max;
1049         ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
1050         if (ret)
1051                 goto unlock;
1052
1053         subflows = pernet->subflows_max;
1054         ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
1055         if (ret)
1056                 goto unlock;
1057
1058         WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
1059         WRITE_ONCE(pernet->subflows_max, subflows);
1060
1061 unlock:
1062         spin_unlock_bh(&pernet->lock);
1063         return ret;
1064 }
1065
1066 static int
1067 mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
1068 {
1069         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1070         struct sk_buff *msg;
1071         void *reply;
1072
1073         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1074         if (!msg)
1075                 return -ENOMEM;
1076
1077         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1078                                   MPTCP_PM_CMD_GET_LIMITS);
1079         if (!reply)
1080                 goto fail;
1081
1082         if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
1083                         READ_ONCE(pernet->add_addr_accept_max)))
1084                 goto fail;
1085
1086         if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
1087                         READ_ONCE(pernet->subflows_max)))
1088                 goto fail;
1089
1090         genlmsg_end(msg, reply);
1091         return genlmsg_reply(msg, info);
1092
1093 fail:
1094         GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1095         nlmsg_free(msg);
1096         return -EMSGSIZE;
1097 }
1098
1099 static const struct genl_small_ops mptcp_pm_ops[] = {
1100         {
1101                 .cmd    = MPTCP_PM_CMD_ADD_ADDR,
1102                 .doit   = mptcp_nl_cmd_add_addr,
1103                 .flags  = GENL_ADMIN_PERM,
1104         },
1105         {
1106                 .cmd    = MPTCP_PM_CMD_DEL_ADDR,
1107                 .doit   = mptcp_nl_cmd_del_addr,
1108                 .flags  = GENL_ADMIN_PERM,
1109         },
1110         {
1111                 .cmd    = MPTCP_PM_CMD_FLUSH_ADDRS,
1112                 .doit   = mptcp_nl_cmd_flush_addrs,
1113                 .flags  = GENL_ADMIN_PERM,
1114         },
1115         {
1116                 .cmd    = MPTCP_PM_CMD_GET_ADDR,
1117                 .doit   = mptcp_nl_cmd_get_addr,
1118                 .dumpit   = mptcp_nl_cmd_dump_addrs,
1119         },
1120         {
1121                 .cmd    = MPTCP_PM_CMD_SET_LIMITS,
1122                 .doit   = mptcp_nl_cmd_set_limits,
1123                 .flags  = GENL_ADMIN_PERM,
1124         },
1125         {
1126                 .cmd    = MPTCP_PM_CMD_GET_LIMITS,
1127                 .doit   = mptcp_nl_cmd_get_limits,
1128         },
1129 };
1130
1131 static struct genl_family mptcp_genl_family __ro_after_init = {
1132         .name           = MPTCP_PM_NAME,
1133         .version        = MPTCP_PM_VER,
1134         .maxattr        = MPTCP_PM_ATTR_MAX,
1135         .policy         = mptcp_pm_policy,
1136         .netnsok        = true,
1137         .module         = THIS_MODULE,
1138         .small_ops      = mptcp_pm_ops,
1139         .n_small_ops    = ARRAY_SIZE(mptcp_pm_ops),
1140         .mcgrps         = mptcp_pm_mcgrps,
1141         .n_mcgrps       = ARRAY_SIZE(mptcp_pm_mcgrps),
1142 };
1143
1144 static int __net_init pm_nl_init_net(struct net *net)
1145 {
1146         struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
1147
1148         INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
1149         __reset_counters(pernet);
1150         pernet->next_id = 1;
1151         spin_lock_init(&pernet->lock);
1152         return 0;
1153 }
1154
1155 static void __net_exit pm_nl_exit_net(struct list_head *net_list)
1156 {
1157         struct net *net;
1158
1159         list_for_each_entry(net, net_list, exit_list) {
1160                 struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
1161
1162                 /* net is removed from namespace list, can't race with
1163                  * other modifiers
1164                  */
1165                 __flush_addrs(net, &pernet->local_addr_list);
1166         }
1167 }
1168
1169 static struct pernet_operations mptcp_pm_pernet_ops = {
1170         .init = pm_nl_init_net,
1171         .exit_batch = pm_nl_exit_net,
1172         .id = &pm_nl_pernet_id,
1173         .size = sizeof(struct pm_nl_pernet),
1174 };
1175
1176 void __init mptcp_pm_nl_init(void)
1177 {
1178         if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
1179                 panic("Failed to register MPTCP PM pernet subsystem.\n");
1180
1181         if (genl_register_family(&mptcp_genl_family))
1182                 panic("Failed to register MPTCP PM netlink family\n");
1183 }