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_add_entry {
  26         struct list_head        list;
  27         struct mptcp_addr_info  addr;
  28         struct timer_list       add_timer;
  29         struct mptcp_sock       *sock;
  30         u8                      retrans_times;
  31 };
  32
  33 struct pm_nl_pernet {
  34         /* protects pernet updates */
  35         spinlock_t              lock;
  36         struct list_head        local_addr_list;
  37         unsigned int            addrs;
  38         unsigned int            stale_loss_cnt;
  39         unsigned int            add_addr_signal_max;
  40         unsigned int            add_addr_accept_max;
  41         unsigned int            local_addr_max;
  42         unsigned int            subflows_max;
  43         unsigned int            next_id;
  44         DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
  45 };
  46
  47 #define MPTCP_PM_ADDR_MAX       8
  48 #define ADD_ADDR_RETRANS_MAX    3
  49
  50 static struct pm_nl_pernet *pm_nl_get_pernet(const struct net *net)
  51 {
  52         return net_generic(net, pm_nl_pernet_id);
  53 }
  54
  55 static struct pm_nl_pernet *
  56 pm_nl_get_pernet_from_msk(const struct mptcp_sock *msk)
  57 {
  58         return pm_nl_get_pernet(sock_net((struct sock *)msk));
  59 }
  60
  61 bool mptcp_addresses_equal(const struct mptcp_addr_info *a,
  62                            const struct mptcp_addr_info *b, bool use_port)
  63 {
  64         bool addr_equals = false;
  65
  66         if (a->family == b->family) {
  67                 if (a->family == AF_INET)
  68                         addr_equals = a->addr.s_addr == b->addr.s_addr;
  69 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  70                 else
  71                         addr_equals = !ipv6_addr_cmp(&a->addr6, &b->addr6);
  72         } else if (a->family == AF_INET) {
  73                 if (ipv6_addr_v4mapped(&b->addr6))
  74                         addr_equals = a->addr.s_addr == b->addr6.s6_addr32[3];
  75         } else if (b->family == AF_INET) {
  76                 if (ipv6_addr_v4mapped(&a->addr6))
  77                         addr_equals = a->addr6.s6_addr32[3] == b->addr.s_addr;
  78 #endif
  79         }
  80
  81         if (!addr_equals)
  82                 return false;
  83         if (!use_port)
  84                 return true;
  85
  86         return a->port == b->port;
  87 }
  88
  89 static void local_address(const struct sock_common *skc,
  90                           struct mptcp_addr_info *addr)
  91 {
  92         addr->family = skc->skc_family;
  93         addr->port = htons(skc->skc_num);
  94         if (addr->family == AF_INET)
  95                 addr->addr.s_addr = skc->skc_rcv_saddr;
  96 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  97         else if (addr->family == AF_INET6)
  98                 addr->addr6 = skc->skc_v6_rcv_saddr;
  99 #endif
 100 }
 101
 102 static void remote_address(const struct sock_common *skc,
 103                            struct mptcp_addr_info *addr)
 104 {
 105         addr->family = skc->skc_family;
 106         addr->port = skc->skc_dport;
 107         if (addr->family == AF_INET)
 108                 addr->addr.s_addr = skc->skc_daddr;
 109 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 110         else if (addr->family == AF_INET6)
 111                 addr->addr6 = skc->skc_v6_daddr;
 112 #endif
 113 }
 114
 115 static bool lookup_subflow_by_saddr(const struct list_head *list,
 116                                     const struct mptcp_addr_info *saddr)
 117 {
 118         struct mptcp_subflow_context *subflow;
 119         struct mptcp_addr_info cur;
 120         struct sock_common *skc;
 121
 122         list_for_each_entry(subflow, list, node) {
 123                 skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 124
 125                 local_address(skc, &cur);
 126                 if (mptcp_addresses_equal(&cur, saddr, saddr->port))
 127                         return true;
 128         }
 129
 130         return false;
 131 }
 132
 133 static bool lookup_subflow_by_daddr(const struct list_head *list,
 134                                     const struct mptcp_addr_info *daddr)
 135 {
 136         struct mptcp_subflow_context *subflow;
 137         struct mptcp_addr_info cur;
 138         struct sock_common *skc;
 139
 140         list_for_each_entry(subflow, list, node) {
 141                 skc = (struct sock_common *)mptcp_subflow_tcp_sock(subflow);
 142
 143                 remote_address(skc, &cur);
 144                 if (mptcp_addresses_equal(&cur, daddr, daddr->port))
 145                         return true;
 146         }
 147
 148         return false;
 149 }
 150
 151 static struct mptcp_pm_addr_entry *
 152 select_local_address(const struct pm_nl_pernet *pernet,
 153                      const struct mptcp_sock *msk)
 154 {
 155         const struct sock *sk = (const struct sock *)msk;
 156         struct mptcp_pm_addr_entry *entry, *ret = NULL;
 157
 158         msk_owned_by_me(msk);
 159
 160         rcu_read_lock();
 161         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 162                 if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW))
 163                         continue;
 164
 165                 if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 166                         continue;
 167
 168                 if (entry->addr.family != sk->sk_family) {
 169 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 170                         if ((entry->addr.family == AF_INET &&
 171                              !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
 172                             (sk->sk_family == AF_INET &&
 173                              !ipv6_addr_v4mapped(&entry->addr.addr6)))
 174 #endif
 175                                 continue;
 176                 }
 177
 178                 ret = entry;
 179                 break;
 180         }
 181         rcu_read_unlock();
 182         return ret;
 183 }
 184
 185 static struct mptcp_pm_addr_entry *
 186 select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
 187 {
 188         struct mptcp_pm_addr_entry *entry, *ret = NULL;
 189
 190         rcu_read_lock();
 191         /* do not keep any additional per socket state, just signal
 192          * the address list in order.
 193          * Note: removal from the local address list during the msk life-cycle
 194          * can lead to additional addresses not being announced.
 195          */
 196         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 197                 if (!test_bit(entry->addr.id, msk->pm.id_avail_bitmap))
 198                         continue;
 199
 200                 if (!(entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL))
 201                         continue;
 202
 203                 ret = entry;
 204                 break;
 205         }
 206         rcu_read_unlock();
 207         return ret;
 208 }
 209
 210 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
 211 {
 212         const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 213
 214         return READ_ONCE(pernet->add_addr_signal_max);
 215 }
 216 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
 217
 218 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 219 {
 220         struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 221
 222         return READ_ONCE(pernet->add_addr_accept_max);
 223 }
 224 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
 225
 226 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
 227 {
 228         struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 229
 230         return READ_ONCE(pernet->subflows_max);
 231 }
 232 EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
 233
 234 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
 235 {
 236         struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 237
 238         return READ_ONCE(pernet->local_addr_max);
 239 }
 240 EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
 241
 242 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 243 {
 244         struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 245
 246         if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
 247             (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,
 248                                MPTCP_PM_MAX_ADDR_ID + 1, 0) == MPTCP_PM_MAX_ADDR_ID + 1)) {
 249                 WRITE_ONCE(msk->pm.work_pending, false);
 250                 return false;
 251         }
 252         return true;
 253 }
 254
 255 struct mptcp_pm_add_entry *
 256 mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
 257                                 const struct mptcp_addr_info *addr)
 258 {
 259         struct mptcp_pm_add_entry *entry;
 260
 261         lockdep_assert_held(&msk->pm.lock);
 262
 263         list_for_each_entry(entry, &msk->pm.anno_list, list) {
 264                 if (mptcp_addresses_equal(&entry->addr, addr, true))
 265                         return entry;
 266         }
 267
 268         return NULL;
 269 }
 270
 271 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk)
 272 {
 273         struct mptcp_pm_add_entry *entry;
 274         struct mptcp_addr_info saddr;
 275         bool ret = false;
 276
 277         local_address((struct sock_common *)sk, &saddr);
 278
 279         spin_lock_bh(&msk->pm.lock);
 280         list_for_each_entry(entry, &msk->pm.anno_list, list) {
 281                 if (mptcp_addresses_equal(&entry->addr, &saddr, true)) {
 282                         ret = true;
 283                         goto out;
 284                 }
 285         }
 286
 287 out:
 288         spin_unlock_bh(&msk->pm.lock);
 289         return ret;
 290 }
 291
 292 static void mptcp_pm_add_timer(struct timer_list *timer)
 293 {
 294         struct mptcp_pm_add_entry *entry = from_timer(entry, timer, add_timer);
 295         struct mptcp_sock *msk = entry->sock;
 296         struct sock *sk = (struct sock *)msk;
 297
 298         pr_debug("msk=%p", msk);
 299
 300         if (!msk)
 301                 return;
 302
 303         if (inet_sk_state_load(sk) == TCP_CLOSE)
 304                 return;
 305
 306         if (!entry->addr.id)
 307                 return;
 308
 309         if (mptcp_pm_should_add_signal_addr(msk)) {
 310                 sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 311                 goto out;
 312         }
 313
 314         spin_lock_bh(&msk->pm.lock);
 315
 316         if (!mptcp_pm_should_add_signal_addr(msk)) {
 317                 pr_debug("retransmit ADD_ADDR id=%d", entry->addr.id);
 318                 mptcp_pm_announce_addr(msk, &entry->addr, false);
 319                 mptcp_pm_add_addr_send_ack(msk);
 320                 entry->retrans_times++;
 321         }
 322
 323         if (entry->retrans_times < ADD_ADDR_RETRANS_MAX)
 324                 sk_reset_timer(sk, timer,
 325                                jiffies + mptcp_get_add_addr_timeout(sock_net(sk)));
 326
 327         spin_unlock_bh(&msk->pm.lock);
 328
 329         if (entry->retrans_times == ADD_ADDR_RETRANS_MAX)
 330                 mptcp_pm_subflow_established(msk);
 331
 332 out:
 333         __sock_put(sk);
 334 }
 335
 336 struct mptcp_pm_add_entry *
 337 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 338                        const struct mptcp_addr_info *addr, bool check_id)
 339 {
 340         struct mptcp_pm_add_entry *entry;
 341         struct sock *sk = (struct sock *)msk;
 342
 343         spin_lock_bh(&msk->pm.lock);
 344         entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
 345         if (entry && (!check_id || entry->addr.id == addr->id))
 346                 entry->retrans_times = ADD_ADDR_RETRANS_MAX;
 347         spin_unlock_bh(&msk->pm.lock);
 348
 349         if (entry && (!check_id || entry->addr.id == addr->id))
 350                 sk_stop_timer_sync(sk, &entry->add_timer);
 351
 352         return entry;
 353 }
 354
 355 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 356                               const struct mptcp_pm_addr_entry *entry)
 357 {
 358         struct mptcp_pm_add_entry *add_entry = NULL;
 359         struct sock *sk = (struct sock *)msk;
 360         struct net *net = sock_net(sk);
 361
 362         lockdep_assert_held(&msk->pm.lock);
 363
 364         add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
 365
 366         if (add_entry) {
 367                 if (mptcp_pm_is_kernel(msk))
 368                         return false;
 369
 370                 sk_reset_timer(sk, &add_entry->add_timer,
 371                                jiffies + mptcp_get_add_addr_timeout(net));
 372                 return true;
 373         }
 374
 375         add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
 376         if (!add_entry)
 377                 return false;
 378
 379         list_add(&add_entry->list, &msk->pm.anno_list);
 380
 381         add_entry->addr = entry->addr;
 382         add_entry->sock = msk;
 383         add_entry->retrans_times = 0;
 384
 385         timer_setup(&add_entry->add_timer, mptcp_pm_add_timer, 0);
 386         sk_reset_timer(sk, &add_entry->add_timer,
 387                        jiffies + mptcp_get_add_addr_timeout(net));
 388
 389         return true;
 390 }
 391
 392 void mptcp_pm_free_anno_list(struct mptcp_sock *msk)
 393 {
 394         struct mptcp_pm_add_entry *entry, *tmp;
 395         struct sock *sk = (struct sock *)msk;
 396         LIST_HEAD(free_list);
 397
 398         pr_debug("msk=%p", msk);
 399
 400         spin_lock_bh(&msk->pm.lock);
 401         list_splice_init(&msk->pm.anno_list, &free_list);
 402         spin_unlock_bh(&msk->pm.lock);
 403
 404         list_for_each_entry_safe(entry, tmp, &free_list, list) {
 405                 sk_stop_timer_sync(sk, &entry->add_timer);
 406                 kfree(entry);
 407         }
 408 }
 409
 410 static bool lookup_address_in_vec(const struct mptcp_addr_info *addrs, unsigned int nr,
 411                                   const struct mptcp_addr_info *addr)
 412 {
 413         int i;
 414
 415         for (i = 0; i < nr; i++) {
 416                 if (addrs[i].id == addr->id)
 417                         return true;
 418         }
 419
 420         return false;
 421 }
 422
 423 /* Fill all the remote addresses into the array addrs[],
 424  * and return the array size.
 425  */
 426 static unsigned int fill_remote_addresses_vec(struct mptcp_sock *msk, bool fullmesh,
 427                                               struct mptcp_addr_info *addrs)
 428 {
 429         bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
 430         struct sock *sk = (struct sock *)msk, *ssk;
 431         struct mptcp_subflow_context *subflow;
 432         struct mptcp_addr_info remote = { 0 };
 433         unsigned int subflows_max;
 434         int i = 0;
 435
 436         subflows_max = mptcp_pm_get_subflows_max(msk);
 437         remote_address((struct sock_common *)sk, &remote);
 438
 439         /* Non-fullmesh endpoint, fill in the single entry
 440          * corresponding to the primary MPC subflow remote address
 441          */
 442         if (!fullmesh) {
 443                 if (deny_id0)
 444                         return 0;
 445
 446                 msk->pm.subflows++;
 447                 addrs[i++] = remote;
 448         } else {
 449                 mptcp_for_each_subflow(msk, subflow) {
 450                         ssk = mptcp_subflow_tcp_sock(subflow);
 451                         remote_address((struct sock_common *)ssk, &addrs[i]);
 452                         addrs[i].id = subflow->remote_id;
 453                         if (deny_id0 && !addrs[i].id)
 454                                 continue;
 455
 456                         if (!lookup_address_in_vec(addrs, i, &addrs[i]) &&
 457                             msk->pm.subflows < subflows_max) {
 458                                 msk->pm.subflows++;
 459                                 i++;
 460                         }
 461                 }
 462         }
 463
 464         return i;
 465 }
 466
 467 static void __mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 468                                 bool prio, bool backup)
 469 {
 470         struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 471         bool slow;
 472
 473         pr_debug("send ack for %s",
 474                  prio ? "mp_prio" : (mptcp_pm_should_add_signal(msk) ? "add_addr" : "rm_addr"));
 475
 476         slow = lock_sock_fast(ssk);
 477         if (prio) {
 478                 if (subflow->backup != backup)
 479                         msk->last_snd = NULL;
 480
 481                 subflow->send_mp_prio = 1;
 482                 subflow->backup = backup;
 483                 subflow->request_bkup = backup;
 484         }
 485
 486         __mptcp_subflow_send_ack(ssk);
 487         unlock_sock_fast(ssk, slow);
 488 }
 489
 490 static void mptcp_pm_send_ack(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 491                               bool prio, bool backup)
 492 {
 493         spin_unlock_bh(&msk->pm.lock);
 494         __mptcp_pm_send_ack(msk, subflow, prio, backup);
 495         spin_lock_bh(&msk->pm.lock);
 496 }
 497
 498 static struct mptcp_pm_addr_entry *
 499 __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 500 {
 501         struct mptcp_pm_addr_entry *entry;
 502
 503         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 504                 if (entry->addr.id == id)
 505                         return entry;
 506         }
 507         return NULL;
 508 }
 509
 510 static struct mptcp_pm_addr_entry *
 511 __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
 512               bool lookup_by_id)
 513 {
 514         struct mptcp_pm_addr_entry *entry;
 515
 516         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 517                 if ((!lookup_by_id && mptcp_addresses_equal(&entry->addr, info, true)) ||
 518                     (lookup_by_id && entry->addr.id == info->id))
 519                         return entry;
 520         }
 521         return NULL;
 522 }
 523
 524 static int
 525 lookup_id_by_addr(const struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)
 526 {
 527         const struct mptcp_pm_addr_entry *entry;
 528         int ret = -1;
 529
 530         rcu_read_lock();
 531         list_for_each_entry(entry, &pernet->local_addr_list, list) {
 532                 if (mptcp_addresses_equal(&entry->addr, addr, entry->addr.port)) {
 533                         ret = entry->addr.id;
 534                         break;
 535                 }
 536         }
 537         rcu_read_unlock();
 538         return ret;
 539 }
 540
 541 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 542 {
 543         struct sock *sk = (struct sock *)msk;
 544         struct mptcp_pm_addr_entry *local;
 545         unsigned int add_addr_signal_max;
 546         unsigned int local_addr_max;
 547         struct pm_nl_pernet *pernet;
 548         unsigned int subflows_max;
 549
 550         pernet = pm_nl_get_pernet(sock_net(sk));
 551
 552         add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
 553         local_addr_max = mptcp_pm_get_local_addr_max(msk);
 554         subflows_max = mptcp_pm_get_subflows_max(msk);
 555
 556         /* do lazy endpoint usage accounting for the MPC subflows */
 557         if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
 558                 struct mptcp_addr_info mpc_addr;
 559                 int mpc_id;
 560
 561                 local_address((struct sock_common *)msk->first, &mpc_addr);
 562                 mpc_id = lookup_id_by_addr(pernet, &mpc_addr);
 563                 if (mpc_id >= 0)
 564                         __clear_bit(mpc_id, msk->pm.id_avail_bitmap);
 565
 566                 msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
 567         }
 568
 569         pr_debug("local %d:%d signal %d:%d subflows %d:%d\n",
 570                  msk->pm.local_addr_used, local_addr_max,
 571                  msk->pm.add_addr_signaled, add_addr_signal_max,
 572                  msk->pm.subflows, subflows_max);
 573
 574         /* check first for announce */
 575         if (msk->pm.add_addr_signaled < add_addr_signal_max) {
 576                 local = select_signal_address(pernet, msk);
 577
 578                 /* due to racing events on both ends we can reach here while
 579                  * previous add address is still running: if we invoke now
 580                  * mptcp_pm_announce_addr(), that will fail and the
 581                  * corresponding id will be marked as used.
 582                  * Instead let the PM machinery reschedule us when the
 583                  * current address announce will be completed.
 584                  */
 585                 if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
 586                         return;
 587
 588                 if (local) {
 589                         if (mptcp_pm_alloc_anno_list(msk, local)) {
 590                                 __clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 591                                 msk->pm.add_addr_signaled++;
 592                                 mptcp_pm_announce_addr(msk, &local->addr, false);
 593                                 mptcp_pm_nl_addr_send_ack(msk);
 594                         }
 595                 }
 596         }
 597
 598         /* check if should create a new subflow */
 599         while (msk->pm.local_addr_used < local_addr_max &&
 600                msk->pm.subflows < subflows_max) {
 601                 struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 602                 bool fullmesh;
 603                 int i, nr;
 604
 605                 local = select_local_address(pernet, msk);
 606                 if (!local)
 607                         break;
 608
 609                 fullmesh = !!(local->flags & MPTCP_PM_ADDR_FLAG_FULLMESH);
 610
 611                 msk->pm.local_addr_used++;
 612                 nr = fill_remote_addresses_vec(msk, fullmesh, addrs);
 613                 if (nr)
 614                         __clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 615                 spin_unlock_bh(&msk->pm.lock);
 616                 for (i = 0; i < nr; i++)
 617                         __mptcp_subflow_connect(sk, &local->addr, &addrs[i]);
 618                 spin_lock_bh(&msk->pm.lock);
 619         }
 620         mptcp_pm_nl_check_work_pending(msk);
 621 }
 622
 623 static void mptcp_pm_nl_fully_established(struct mptcp_sock *msk)
 624 {
 625         mptcp_pm_create_subflow_or_signal_addr(msk);
 626 }
 627
 628 static void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk)
 629 {
 630         mptcp_pm_create_subflow_or_signal_addr(msk);
 631 }
 632
 633 /* Fill all the local addresses into the array addrs[],
 634  * and return the array size.
 635  */
 636 static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 637                                              struct mptcp_addr_info *addrs)
 638 {
 639         struct sock *sk = (struct sock *)msk;
 640         struct mptcp_pm_addr_entry *entry;
 641         struct mptcp_addr_info local;
 642         struct pm_nl_pernet *pernet;
 643         unsigned int subflows_max;
 644         int i = 0;
 645
 646         pernet = pm_nl_get_pernet_from_msk(msk);
 647         subflows_max = mptcp_pm_get_subflows_max(msk);
 648
 649         rcu_read_lock();
 650         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 651                 if (!(entry->flags & MPTCP_PM_ADDR_FLAG_FULLMESH))
 652                         continue;
 653
 654                 if (entry->addr.family != sk->sk_family) {
 655 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 656                         if ((entry->addr.family == AF_INET &&
 657                              !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) ||
 658                             (sk->sk_family == AF_INET &&
 659                              !ipv6_addr_v4mapped(&entry->addr.addr6)))
 660 #endif
 661                                 continue;
 662                 }
 663
 664                 if (msk->pm.subflows < subflows_max) {
 665                         msk->pm.subflows++;
 666                         addrs[i++] = entry->addr;
 667                 }
 668         }
 669         rcu_read_unlock();
 670
 671         /* If the array is empty, fill in the single
 672          * 'IPADDRANY' local address
 673          */
 674         if (!i) {
 675                 memset(&local, 0, sizeof(local));
 676                 local.family = msk->pm.remote.family;
 677
 678                 msk->pm.subflows++;
 679                 addrs[i++] = local;
 680         }
 681
 682         return i;
 683 }
 684
 685 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 686 {
 687         struct mptcp_addr_info addrs[MPTCP_PM_ADDR_MAX];
 688         struct sock *sk = (struct sock *)msk;
 689         unsigned int add_addr_accept_max;
 690         struct mptcp_addr_info remote;
 691         unsigned int subflows_max;
 692         int i, nr;
 693
 694         add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
 695         subflows_max = mptcp_pm_get_subflows_max(msk);
 696
 697         pr_debug("accepted %d:%d remote family %d",
 698                  msk->pm.add_addr_accepted, add_addr_accept_max,
 699                  msk->pm.remote.family);
 700
 701         remote = msk->pm.remote;
 702         mptcp_pm_announce_addr(msk, &remote, true);
 703         mptcp_pm_nl_addr_send_ack(msk);
 704
 705         if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
 706                 return;
 707
 708         /* pick id 0 port, if none is provided the remote address */
 709         if (!remote.port)
 710                 remote.port = sk->sk_dport;
 711
 712         /* connect to the specified remote address, using whatever
 713          * local address the routing configuration will pick.
 714          */
 715         nr = fill_local_addresses_vec(msk, addrs);
 716
 717         msk->pm.add_addr_accepted++;
 718         if (msk->pm.add_addr_accepted >= add_addr_accept_max ||
 719             msk->pm.subflows >= subflows_max)
 720                 WRITE_ONCE(msk->pm.accept_addr, false);
 721
 722         spin_unlock_bh(&msk->pm.lock);
 723         for (i = 0; i < nr; i++)
 724                 __mptcp_subflow_connect(sk, &addrs[i], &remote);
 725         spin_lock_bh(&msk->pm.lock);
 726 }
 727
 728 void mptcp_pm_nl_addr_send_ack(struct mptcp_sock *msk)
 729 {
 730         struct mptcp_subflow_context *subflow;
 731
 732         msk_owned_by_me(msk);
 733         lockdep_assert_held(&msk->pm.lock);
 734
 735         if (!mptcp_pm_should_add_signal(msk) &&
 736             !mptcp_pm_should_rm_signal(msk))
 737                 return;
 738
 739         subflow = list_first_entry_or_null(&msk->conn_list, typeof(*subflow), node);
 740         if (subflow)
 741                 mptcp_pm_send_ack(msk, subflow, false, false);
 742 }
 743
 744 int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 745                                  struct mptcp_addr_info *addr,
 746                                  struct mptcp_addr_info *rem,
 747                                  u8 bkup)
 748 {
 749         struct mptcp_subflow_context *subflow;
 750
 751         pr_debug("bkup=%d", bkup);
 752
 753         mptcp_for_each_subflow(msk, subflow) {
 754                 struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 755                 struct mptcp_addr_info local, remote;
 756
 757                 local_address((struct sock_common *)ssk, &local);
 758                 if (!mptcp_addresses_equal(&local, addr, addr->port))
 759                         continue;
 760
 761                 if (rem && rem->family != AF_UNSPEC) {
 762                         remote_address((struct sock_common *)ssk, &remote);
 763                         if (!mptcp_addresses_equal(&remote, rem, rem->port))
 764                                 continue;
 765                 }
 766
 767                 __mptcp_pm_send_ack(msk, subflow, true, bkup);
 768                 return 0;
 769         }
 770
 771         return -EINVAL;
 772 }
 773
 774 static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
 775                                            const struct mptcp_rm_list *rm_list,
 776                                            enum linux_mptcp_mib_field rm_type)
 777 {
 778         struct mptcp_subflow_context *subflow, *tmp;
 779         struct sock *sk = (struct sock *)msk;
 780         u8 i;
 781
 782         pr_debug("%s rm_list_nr %d",
 783                  rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow", rm_list->nr);
 784
 785         msk_owned_by_me(msk);
 786
 787         if (sk->sk_state == TCP_LISTEN)
 788                 return;
 789
 790         if (!rm_list->nr)
 791                 return;
 792
 793         if (list_empty(&msk->conn_list))
 794                 return;
 795
 796         for (i = 0; i < rm_list->nr; i++) {
 797                 bool removed = false;
 798
 799                 list_for_each_entry_safe(subflow, tmp, &msk->conn_list, node) {
 800                         struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 801                         int how = RCV_SHUTDOWN | SEND_SHUTDOWN;
 802                         u8 id = subflow->local_id;
 803
 804                         if (rm_type == MPTCP_MIB_RMADDR)
 805                                 id = subflow->remote_id;
 806
 807                         if (rm_list->ids[i] != id)
 808                                 continue;
 809
 810                         pr_debug(" -> %s rm_list_ids[%d]=%u local_id=%u remote_id=%u",
 811                                  rm_type == MPTCP_MIB_RMADDR ? "address" : "subflow",
 812                                  i, rm_list->ids[i], subflow->local_id, subflow->remote_id);
 813                         spin_unlock_bh(&msk->pm.lock);
 814                         mptcp_subflow_shutdown(sk, ssk, how);
 815
 816                         /* the following takes care of updating the subflows counter */
 817                         mptcp_close_ssk(sk, ssk, subflow);
 818                         spin_lock_bh(&msk->pm.lock);
 819
 820                         removed = true;
 821                         __MPTCP_INC_STATS(sock_net(sk), rm_type);
 822                 }
 823                 if (rm_type == MPTCP_MIB_RMSUBFLOW)
 824                         __set_bit(rm_list->ids[i], msk->pm.id_avail_bitmap);
 825                 if (!removed)
 826                         continue;
 827
 828                 if (!mptcp_pm_is_kernel(msk))
 829                         continue;
 830
 831                 if (rm_type == MPTCP_MIB_RMADDR) {
 832                         msk->pm.add_addr_accepted--;
 833                         WRITE_ONCE(msk->pm.accept_addr, true);
 834                 } else if (rm_type == MPTCP_MIB_RMSUBFLOW) {
 835                         msk->pm.local_addr_used--;
 836                 }
 837         }
 838 }
 839
 840 static void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 841 {
 842         mptcp_pm_nl_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR);
 843 }
 844
 845 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk,
 846                                      const struct mptcp_rm_list *rm_list)
 847 {
 848         mptcp_pm_nl_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW);
 849 }
 850
 851 void mptcp_pm_nl_work(struct mptcp_sock *msk)
 852 {
 853         struct mptcp_pm_data *pm = &msk->pm;
 854
 855         msk_owned_by_me(msk);
 856
 857         if (!(pm->status & MPTCP_PM_WORK_MASK))
 858                 return;
 859
 860         spin_lock_bh(&msk->pm.lock);
 861
 862         pr_debug("msk=%p status=%x", msk, pm->status);
 863         if (pm->status & BIT(MPTCP_PM_ADD_ADDR_RECEIVED)) {
 864                 pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_RECEIVED);
 865                 mptcp_pm_nl_add_addr_received(msk);
 866         }
 867         if (pm->status & BIT(MPTCP_PM_ADD_ADDR_SEND_ACK)) {
 868                 pm->status &= ~BIT(MPTCP_PM_ADD_ADDR_SEND_ACK);
 869                 mptcp_pm_nl_addr_send_ack(msk);
 870         }
 871         if (pm->status & BIT(MPTCP_PM_RM_ADDR_RECEIVED)) {
 872                 pm->status &= ~BIT(MPTCP_PM_RM_ADDR_RECEIVED);
 873                 mptcp_pm_nl_rm_addr_received(msk);
 874         }
 875         if (pm->status & BIT(MPTCP_PM_ESTABLISHED)) {
 876                 pm->status &= ~BIT(MPTCP_PM_ESTABLISHED);
 877                 mptcp_pm_nl_fully_established(msk);
 878         }
 879         if (pm->status & BIT(MPTCP_PM_SUBFLOW_ESTABLISHED)) {
 880                 pm->status &= ~BIT(MPTCP_PM_SUBFLOW_ESTABLISHED);
 881                 mptcp_pm_nl_subflow_established(msk);
 882         }
 883
 884         spin_unlock_bh(&msk->pm.lock);
 885 }
 886
 887 static bool address_use_port(struct mptcp_pm_addr_entry *entry)
 888 {
 889         return (entry->flags &
 890                 (MPTCP_PM_ADDR_FLAG_SIGNAL | MPTCP_PM_ADDR_FLAG_SUBFLOW)) ==
 891                 MPTCP_PM_ADDR_FLAG_SIGNAL;
 892 }
 893
 894 /* caller must ensure the RCU grace period is already elapsed */
 895 static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry)
 896 {
 897         if (entry->lsk)
 898                 sock_release(entry->lsk);
 899         kfree(entry);
 900 }
 901
 902 static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
 903                                              struct mptcp_pm_addr_entry *entry)
 904 {
 905         struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
 906         unsigned int addr_max;
 907         int ret = -EINVAL;
 908
 909         spin_lock_bh(&pernet->lock);
 910         /* to keep the code simple, don't do IDR-like allocation for address ID,
 911          * just bail when we exceed limits
 912          */
 913         if (pernet->next_id == MPTCP_PM_MAX_ADDR_ID)
 914                 pernet->next_id = 1;
 915         if (pernet->addrs >= MPTCP_PM_ADDR_MAX)
 916                 goto out;
 917         if (test_bit(entry->addr.id, pernet->id_bitmap))
 918                 goto out;
 919
 920         /* do not insert duplicate address, differentiate on port only
 921          * singled addresses
 922          */
 923         if (!address_use_port(entry))
 924                 entry->addr.port = 0;
 925         list_for_each_entry(cur, &pernet->local_addr_list, list) {
 926                 if (mptcp_addresses_equal(&cur->addr, &entry->addr,
 927                                           cur->addr.port || entry->addr.port)) {
 928                         /* allow replacing the exiting endpoint only if such
 929                          * endpoint is an implicit one and the user-space
 930                          * did not provide an endpoint id
 931                          */
 932                         if (!(cur->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT))
 933                                 goto out;
 934                         if (entry->addr.id)
 935                                 goto out;
 936
 937                         pernet->addrs--;
 938                         entry->addr.id = cur->addr.id;
 939                         list_del_rcu(&cur->list);
 940                         del_entry = cur;
 941                         break;
 942                 }
 943         }
 944
 945         if (!entry->addr.id) {
 946 find_next:
 947                 entry->addr.id = find_next_zero_bit(pernet->id_bitmap,
 948                                                     MPTCP_PM_MAX_ADDR_ID + 1,
 949                                                     pernet->next_id);
 950                 if (!entry->addr.id && pernet->next_id != 1) {
 951                         pernet->next_id = 1;
 952                         goto find_next;
 953                 }
 954         }
 955
 956         if (!entry->addr.id)
 957                 goto out;
 958
 959         __set_bit(entry->addr.id, pernet->id_bitmap);
 960         if (entry->addr.id > pernet->next_id)
 961                 pernet->next_id = entry->addr.id;
 962
 963         if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
 964                 addr_max = pernet->add_addr_signal_max;
 965                 WRITE_ONCE(pernet->add_addr_signal_max, addr_max + 1);
 966         }
 967         if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
 968                 addr_max = pernet->local_addr_max;
 969                 WRITE_ONCE(pernet->local_addr_max, addr_max + 1);
 970         }
 971
 972         pernet->addrs++;
 973         if (!entry->addr.port)
 974                 list_add_tail_rcu(&entry->list, &pernet->local_addr_list);
 975         else
 976                 list_add_rcu(&entry->list, &pernet->local_addr_list);
 977         ret = entry->addr.id;
 978
 979 out:
 980         spin_unlock_bh(&pernet->lock);
 981
 982         /* just replaced an existing entry, free it */
 983         if (del_entry) {
 984                 synchronize_rcu();
 985                 __mptcp_pm_release_addr_entry(del_entry);
 986         }
 987         return ret;
 988 }
 989
 990 static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 991                                             struct mptcp_pm_addr_entry *entry)
 992 {
 993         int addrlen = sizeof(struct sockaddr_in);
 994         struct sockaddr_storage addr;
 995         struct mptcp_sock *msk;
 996         struct socket *ssock;
 997         int backlog = 1024;
 998         int err;
 999
1000         err = sock_create_kern(sock_net(sk), entry->addr.family,
1001                                SOCK_STREAM, IPPROTO_MPTCP, &entry->lsk);
1002         if (err)
1003                 return err;
1004
1005         msk = mptcp_sk(entry->lsk->sk);
1006         if (!msk) {
1007                 err = -EINVAL;
1008                 goto out;
1009         }
1010
1011         ssock = __mptcp_nmpc_socket(msk);
1012         if (!ssock) {
1013                 err = -EINVAL;
1014                 goto out;
1015         }
1016
1017         mptcp_info2sockaddr(&entry->addr, &addr, entry->addr.family);
1018 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1019         if (entry->addr.family == AF_INET6)
1020                 addrlen = sizeof(struct sockaddr_in6);
1021 #endif
1022         err = kernel_bind(ssock, (struct sockaddr *)&addr, addrlen);
1023         if (err) {
1024                 pr_warn("kernel_bind error, err=%d", err);
1025                 goto out;
1026         }
1027
1028         err = kernel_listen(ssock, backlog);
1029         if (err) {
1030                 pr_warn("kernel_listen error, err=%d", err);
1031                 goto out;
1032         }
1033
1034         return 0;
1035
1036 out:
1037         sock_release(entry->lsk);
1038         return err;
1039 }
1040
1041 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
1042 {
1043         struct mptcp_pm_addr_entry *entry;
1044         struct mptcp_addr_info skc_local;
1045         struct mptcp_addr_info msk_local;
1046         struct pm_nl_pernet *pernet;
1047         int ret = -1;
1048
1049         if (WARN_ON_ONCE(!msk))
1050                 return -1;
1051
1052         /* The 0 ID mapping is defined by the first subflow, copied into the msk
1053          * addr
1054          */
1055         local_address((struct sock_common *)msk, &msk_local);
1056         local_address((struct sock_common *)skc, &skc_local);
1057         if (mptcp_addresses_equal(&msk_local, &skc_local, false))
1058                 return 0;
1059
1060         if (mptcp_pm_is_userspace(msk))
1061                 return mptcp_userspace_pm_get_local_id(msk, &skc_local);
1062
1063         pernet = pm_nl_get_pernet_from_msk(msk);
1064
1065         rcu_read_lock();
1066         list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
1067                 if (mptcp_addresses_equal(&entry->addr, &skc_local, entry->addr.port)) {
1068                         ret = entry->addr.id;
1069                         break;
1070                 }
1071         }
1072         rcu_read_unlock();
1073         if (ret >= 0)
1074                 return ret;
1075
1076         /* address not found, add to local list */
1077         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
1078         if (!entry)
1079                 return -ENOMEM;
1080
1081         entry->addr = skc_local;
1082         entry->addr.id = 0;
1083         entry->addr.port = 0;
1084         entry->ifindex = 0;
1085         entry->flags = MPTCP_PM_ADDR_FLAG_IMPLICIT;
1086         entry->lsk = NULL;
1087         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
1088         if (ret < 0)
1089                 kfree(entry);
1090
1091         return ret;
1092 }
1093
1094 #define MPTCP_PM_CMD_GRP_OFFSET       0
1095 #define MPTCP_PM_EV_GRP_OFFSET        1
1096
1097 static const struct genl_multicast_group mptcp_pm_mcgrps[] = {
1098         [MPTCP_PM_CMD_GRP_OFFSET]       = { .name = MPTCP_PM_CMD_GRP_NAME, },
1099         [MPTCP_PM_EV_GRP_OFFSET]        = { .name = MPTCP_PM_EV_GRP_NAME,
1100                                             .flags = GENL_UNS_ADMIN_PERM,
1101                                           },
1102 };
1103
1104 static const struct nla_policy
1105 mptcp_pm_addr_policy[MPTCP_PM_ADDR_ATTR_MAX + 1] = {
1106         [MPTCP_PM_ADDR_ATTR_FAMILY]     = { .type       = NLA_U16,      },
1107         [MPTCP_PM_ADDR_ATTR_ID]         = { .type       = NLA_U8,       },
1108         [MPTCP_PM_ADDR_ATTR_ADDR4]      = { .type       = NLA_U32,      },
1109         [MPTCP_PM_ADDR_ATTR_ADDR6]      =
1110                 NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
1111         [MPTCP_PM_ADDR_ATTR_PORT]       = { .type       = NLA_U16       },
1112         [MPTCP_PM_ADDR_ATTR_FLAGS]      = { .type       = NLA_U32       },
1113         [MPTCP_PM_ADDR_ATTR_IF_IDX]     = { .type       = NLA_S32       },
1114 };
1115
1116 static const struct nla_policy mptcp_pm_policy[MPTCP_PM_ATTR_MAX + 1] = {
1117         [MPTCP_PM_ATTR_ADDR]            =
1118                                         NLA_POLICY_NESTED(mptcp_pm_addr_policy),
1119         [MPTCP_PM_ATTR_RCV_ADD_ADDRS]   = { .type       = NLA_U32,      },
1120         [MPTCP_PM_ATTR_SUBFLOWS]        = { .type       = NLA_U32,      },
1121         [MPTCP_PM_ATTR_TOKEN]           = { .type       = NLA_U32,      },
1122         [MPTCP_PM_ATTR_LOC_ID]          = { .type       = NLA_U8,       },
1123         [MPTCP_PM_ATTR_ADDR_REMOTE]     =
1124                                         NLA_POLICY_NESTED(mptcp_pm_addr_policy),
1125 };
1126
1127 void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk)
1128 {
1129         struct mptcp_subflow_context *iter, *subflow = mptcp_subflow_ctx(ssk);
1130         struct sock *sk = (struct sock *)msk;
1131         unsigned int active_max_loss_cnt;
1132         struct net *net = sock_net(sk);
1133         unsigned int stale_loss_cnt;
1134         bool slow;
1135
1136         stale_loss_cnt = mptcp_stale_loss_cnt(net);
1137         if (subflow->stale || !stale_loss_cnt || subflow->stale_count <= stale_loss_cnt)
1138                 return;
1139
1140         /* look for another available subflow not in loss state */
1141         active_max_loss_cnt = max_t(int, stale_loss_cnt - 1, 1);
1142         mptcp_for_each_subflow(msk, iter) {
1143                 if (iter != subflow && mptcp_subflow_active(iter) &&
1144                     iter->stale_count < active_max_loss_cnt) {
1145                         /* we have some alternatives, try to mark this subflow as idle ...*/
1146                         slow = lock_sock_fast(ssk);
1147                         if (!tcp_rtx_and_write_queues_empty(ssk)) {
1148                                 subflow->stale = 1;
1149                                 __mptcp_retransmit_pending_data(sk);
1150                                 MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_SUBFLOWSTALE);
1151                         }
1152                         unlock_sock_fast(ssk, slow);
1153
1154                         /* always try to push the pending data regardless of re-injections:
1155                          * we can possibly use backup subflows now, and subflow selection
1156                          * is cheap under the msk socket lock
1157                          */
1158                         __mptcp_push_pending(sk, 0);
1159                         return;
1160                 }
1161         }
1162 }
1163
1164 static int mptcp_pm_family_to_addr(int family)
1165 {
1166 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1167         if (family == AF_INET6)
1168                 return MPTCP_PM_ADDR_ATTR_ADDR6;
1169 #endif
1170         return MPTCP_PM_ADDR_ATTR_ADDR4;
1171 }
1172
1173 static int mptcp_pm_parse_pm_addr_attr(struct nlattr *tb[],
1174                                        const struct nlattr *attr,
1175                                        struct genl_info *info,
1176                                        struct mptcp_addr_info *addr,
1177                                        bool require_family)
1178 {
1179         int err, addr_addr;
1180
1181         if (!attr) {
1182                 GENL_SET_ERR_MSG(info, "missing address info");
1183                 return -EINVAL;
1184         }
1185
1186         /* no validation needed - was already done via nested policy */
1187         err = nla_parse_nested_deprecated(tb, MPTCP_PM_ADDR_ATTR_MAX, attr,
1188                                           mptcp_pm_addr_policy, info->extack);
1189         if (err)
1190                 return err;
1191
1192         if (tb[MPTCP_PM_ADDR_ATTR_ID])
1193                 addr->id = nla_get_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
1194
1195         if (!tb[MPTCP_PM_ADDR_ATTR_FAMILY]) {
1196                 if (!require_family)
1197                         return err;
1198
1199                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
1200                                     "missing family");
1201                 return -EINVAL;
1202         }
1203
1204         addr->family = nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_FAMILY]);
1205         if (addr->family != AF_INET
1206 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1207             && addr->family != AF_INET6
1208 #endif
1209             ) {
1210                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
1211                                     "unknown address family");
1212                 return -EINVAL;
1213         }
1214         addr_addr = mptcp_pm_family_to_addr(addr->family);
1215         if (!tb[addr_addr]) {
1216                 NL_SET_ERR_MSG_ATTR(info->extack, attr,
1217                                     "missing address data");
1218                 return -EINVAL;
1219         }
1220
1221 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1222         if (addr->family == AF_INET6)
1223                 addr->addr6 = nla_get_in6_addr(tb[addr_addr]);
1224         else
1225 #endif
1226                 addr->addr.s_addr = nla_get_in_addr(tb[addr_addr]);
1227
1228         if (tb[MPTCP_PM_ADDR_ATTR_PORT])
1229                 addr->port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
1230
1231         return err;
1232 }
1233
1234 int mptcp_pm_parse_addr(struct nlattr *attr, struct genl_info *info,
1235                         struct mptcp_addr_info *addr)
1236 {
1237         struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
1238
1239         memset(addr, 0, sizeof(*addr));
1240
1241         return mptcp_pm_parse_pm_addr_attr(tb, attr, info, addr, true);
1242 }
1243
1244 int mptcp_pm_parse_entry(struct nlattr *attr, struct genl_info *info,
1245                          bool require_family,
1246                          struct mptcp_pm_addr_entry *entry)
1247 {
1248         struct nlattr *tb[MPTCP_PM_ADDR_ATTR_MAX + 1];
1249         int err;
1250
1251         memset(entry, 0, sizeof(*entry));
1252
1253         err = mptcp_pm_parse_pm_addr_attr(tb, attr, info, &entry->addr, require_family);
1254         if (err)
1255                 return err;
1256
1257         if (tb[MPTCP_PM_ADDR_ATTR_IF_IDX]) {
1258                 u32 val = nla_get_s32(tb[MPTCP_PM_ADDR_ATTR_IF_IDX]);
1259
1260                 entry->ifindex = val;
1261         }
1262
1263         if (tb[MPTCP_PM_ADDR_ATTR_FLAGS])
1264                 entry->flags = nla_get_u32(tb[MPTCP_PM_ADDR_ATTR_FLAGS]);
1265
1266         if (tb[MPTCP_PM_ADDR_ATTR_PORT])
1267                 entry->addr.port = htons(nla_get_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]));
1268
1269         return 0;
1270 }
1271
1272 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
1273 {
1274         return pm_nl_get_pernet(genl_info_net(info));
1275 }
1276
1277 static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
1278 {
1279         struct mptcp_sock *msk;
1280         long s_slot = 0, s_num = 0;
1281
1282         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1283                 struct sock *sk = (struct sock *)msk;
1284
1285                 if (!READ_ONCE(msk->fully_established) ||
1286                     mptcp_pm_is_userspace(msk))
1287                         goto next;
1288
1289                 lock_sock(sk);
1290                 spin_lock_bh(&msk->pm.lock);
1291                 mptcp_pm_create_subflow_or_signal_addr(msk);
1292                 spin_unlock_bh(&msk->pm.lock);
1293                 release_sock(sk);
1294
1295 next:
1296                 sock_put(sk);
1297                 cond_resched();
1298         }
1299
1300         return 0;
1301 }
1302
1303 static int mptcp_nl_cmd_add_addr(struct sk_buff *skb, struct genl_info *info)
1304 {
1305         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1306         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1307         struct mptcp_pm_addr_entry addr, *entry;
1308         int ret;
1309
1310         ret = mptcp_pm_parse_entry(attr, info, true, &addr);
1311         if (ret < 0)
1312                 return ret;
1313
1314         if (addr.addr.port && !(addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
1315                 GENL_SET_ERR_MSG(info, "flags must have signal when using port");
1316                 return -EINVAL;
1317         }
1318
1319         if (addr.flags & MPTCP_PM_ADDR_FLAG_SIGNAL &&
1320             addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) {
1321                 GENL_SET_ERR_MSG(info, "flags mustn't have both signal and fullmesh");
1322                 return -EINVAL;
1323         }
1324
1325         if (addr.flags & MPTCP_PM_ADDR_FLAG_IMPLICIT) {
1326                 GENL_SET_ERR_MSG(info, "can't create IMPLICIT endpoint");
1327                 return -EINVAL;
1328         }
1329
1330         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1331         if (!entry) {
1332                 GENL_SET_ERR_MSG(info, "can't allocate addr");
1333                 return -ENOMEM;
1334         }
1335
1336         *entry = addr;
1337         if (entry->addr.port) {
1338                 ret = mptcp_pm_nl_create_listen_socket(skb->sk, entry);
1339                 if (ret) {
1340                         GENL_SET_ERR_MSG(info, "create listen socket error");
1341                         kfree(entry);
1342                         return ret;
1343                 }
1344         }
1345         ret = mptcp_pm_nl_append_new_local_addr(pernet, entry);
1346         if (ret < 0) {
1347                 GENL_SET_ERR_MSG(info, "too many addresses or duplicate one");
1348                 if (entry->lsk)
1349                         sock_release(entry->lsk);
1350                 kfree(entry);
1351                 return ret;
1352         }
1353
1354         mptcp_nl_add_subflow_or_signal_addr(sock_net(skb->sk));
1355
1356         return 0;
1357 }
1358
1359 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
1360                                          u8 *flags, int *ifindex)
1361 {
1362         struct mptcp_pm_addr_entry *entry;
1363         struct sock *sk = (struct sock *)msk;
1364         struct net *net = sock_net(sk);
1365
1366         *flags = 0;
1367         *ifindex = 0;
1368
1369         if (id) {
1370                 if (mptcp_pm_is_userspace(msk))
1371                         return mptcp_userspace_pm_get_flags_and_ifindex_by_id(msk,
1372                                                                               id,
1373                                                                               flags,
1374                                                                               ifindex);
1375
1376                 rcu_read_lock();
1377                 entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
1378                 if (entry) {
1379                         *flags = entry->flags;
1380                         *ifindex = entry->ifindex;
1381                 }
1382                 rcu_read_unlock();
1383         }
1384
1385         return 0;
1386 }
1387
1388 static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
1389                                       const struct mptcp_addr_info *addr)
1390 {
1391         struct mptcp_pm_add_entry *entry;
1392
1393         entry = mptcp_pm_del_add_timer(msk, addr, false);
1394         if (entry) {
1395                 list_del(&entry->list);
1396                 kfree(entry);
1397                 return true;
1398         }
1399
1400         return false;
1401 }
1402
1403 static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
1404                                       const struct mptcp_addr_info *addr,
1405                                       bool force)
1406 {
1407         struct mptcp_rm_list list = { .nr = 0 };
1408         bool ret;
1409
1410         list.ids[list.nr++] = addr->id;
1411
1412         ret = remove_anno_list_by_saddr(msk, addr);
1413         if (ret || force) {
1414                 spin_lock_bh(&msk->pm.lock);
1415                 mptcp_pm_remove_addr(msk, &list);
1416                 spin_unlock_bh(&msk->pm.lock);
1417         }
1418         return ret;
1419 }
1420
1421 static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
1422                                                    const struct mptcp_pm_addr_entry *entry)
1423 {
1424         const struct mptcp_addr_info *addr = &entry->addr;
1425         struct mptcp_rm_list list = { .nr = 0 };
1426         long s_slot = 0, s_num = 0;
1427         struct mptcp_sock *msk;
1428
1429         pr_debug("remove_id=%d", addr->id);
1430
1431         list.ids[list.nr++] = addr->id;
1432
1433         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1434                 struct sock *sk = (struct sock *)msk;
1435                 bool remove_subflow;
1436
1437                 if (mptcp_pm_is_userspace(msk))
1438                         goto next;
1439
1440                 if (list_empty(&msk->conn_list)) {
1441                         mptcp_pm_remove_anno_addr(msk, addr, false);
1442                         goto next;
1443                 }
1444
1445                 lock_sock(sk);
1446                 remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr);
1447                 mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&
1448                                           !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
1449                 if (remove_subflow)
1450                         mptcp_pm_remove_subflow(msk, &list);
1451                 release_sock(sk);
1452
1453 next:
1454                 sock_put(sk);
1455                 cond_resched();
1456         }
1457
1458         return 0;
1459 }
1460
1461 static int mptcp_nl_remove_id_zero_address(struct net *net,
1462                                            struct mptcp_addr_info *addr)
1463 {
1464         struct mptcp_rm_list list = { .nr = 0 };
1465         long s_slot = 0, s_num = 0;
1466         struct mptcp_sock *msk;
1467
1468         list.ids[list.nr++] = 0;
1469
1470         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1471                 struct sock *sk = (struct sock *)msk;
1472                 struct mptcp_addr_info msk_local;
1473
1474                 if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
1475                         goto next;
1476
1477                 local_address((struct sock_common *)msk, &msk_local);
1478                 if (!mptcp_addresses_equal(&msk_local, addr, addr->port))
1479                         goto next;
1480
1481                 lock_sock(sk);
1482                 spin_lock_bh(&msk->pm.lock);
1483                 mptcp_pm_remove_addr(msk, &list);
1484                 mptcp_pm_nl_rm_subflow_received(msk, &list);
1485                 spin_unlock_bh(&msk->pm.lock);
1486                 release_sock(sk);
1487
1488 next:
1489                 sock_put(sk);
1490                 cond_resched();
1491         }
1492
1493         return 0;
1494 }
1495
1496 static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info)
1497 {
1498         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1499         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1500         struct mptcp_pm_addr_entry addr, *entry;
1501         unsigned int addr_max;
1502         int ret;
1503
1504         ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1505         if (ret < 0)
1506                 return ret;
1507
1508         /* the zero id address is special: the first address used by the msk
1509          * always gets such an id, so different subflows can have different zero
1510          * id addresses. Additionally zero id is not accounted for in id_bitmap.
1511          * Let's use an 'mptcp_rm_list' instead of the common remove code.
1512          */
1513         if (addr.addr.id == 0)
1514                 return mptcp_nl_remove_id_zero_address(sock_net(skb->sk), &addr.addr);
1515
1516         spin_lock_bh(&pernet->lock);
1517         entry = __lookup_addr_by_id(pernet, addr.addr.id);
1518         if (!entry) {
1519                 GENL_SET_ERR_MSG(info, "address not found");
1520                 spin_unlock_bh(&pernet->lock);
1521                 return -EINVAL;
1522         }
1523         if (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
1524                 addr_max = pernet->add_addr_signal_max;
1525                 WRITE_ONCE(pernet->add_addr_signal_max, addr_max - 1);
1526         }
1527         if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
1528                 addr_max = pernet->local_addr_max;
1529                 WRITE_ONCE(pernet->local_addr_max, addr_max - 1);
1530         }
1531
1532         pernet->addrs--;
1533         list_del_rcu(&entry->list);
1534         __clear_bit(entry->addr.id, pernet->id_bitmap);
1535         spin_unlock_bh(&pernet->lock);
1536
1537         mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), entry);
1538         synchronize_rcu();
1539         __mptcp_pm_release_addr_entry(entry);
1540
1541         return ret;
1542 }
1543
1544 void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk,
1545                                         struct list_head *rm_list)
1546 {
1547         struct mptcp_rm_list alist = { .nr = 0 }, slist = { .nr = 0 };
1548         struct mptcp_pm_addr_entry *entry;
1549
1550         list_for_each_entry(entry, rm_list, list) {
1551                 if (lookup_subflow_by_saddr(&msk->conn_list, &entry->addr) &&
1552                     slist.nr < MPTCP_RM_IDS_MAX)
1553                         slist.ids[slist.nr++] = entry->addr.id;
1554
1555                 if (remove_anno_list_by_saddr(msk, &entry->addr) &&
1556                     alist.nr < MPTCP_RM_IDS_MAX)
1557                         alist.ids[alist.nr++] = entry->addr.id;
1558         }
1559
1560         if (alist.nr) {
1561                 spin_lock_bh(&msk->pm.lock);
1562                 mptcp_pm_remove_addr(msk, &alist);
1563                 spin_unlock_bh(&msk->pm.lock);
1564         }
1565         if (slist.nr)
1566                 mptcp_pm_remove_subflow(msk, &slist);
1567 }
1568
1569 static void mptcp_nl_remove_addrs_list(struct net *net,
1570                                        struct list_head *rm_list)
1571 {
1572         long s_slot = 0, s_num = 0;
1573         struct mptcp_sock *msk;
1574
1575         if (list_empty(rm_list))
1576                 return;
1577
1578         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1579                 struct sock *sk = (struct sock *)msk;
1580
1581                 if (!mptcp_pm_is_userspace(msk)) {
1582                         lock_sock(sk);
1583                         mptcp_pm_remove_addrs_and_subflows(msk, rm_list);
1584                         release_sock(sk);
1585                 }
1586
1587                 sock_put(sk);
1588                 cond_resched();
1589         }
1590 }
1591
1592 /* caller must ensure the RCU grace period is already elapsed */
1593 static void __flush_addrs(struct list_head *list)
1594 {
1595         while (!list_empty(list)) {
1596                 struct mptcp_pm_addr_entry *cur;
1597
1598                 cur = list_entry(list->next,
1599                                  struct mptcp_pm_addr_entry, list);
1600                 list_del_rcu(&cur->list);
1601                 __mptcp_pm_release_addr_entry(cur);
1602         }
1603 }
1604
1605 static void __reset_counters(struct pm_nl_pernet *pernet)
1606 {
1607         WRITE_ONCE(pernet->add_addr_signal_max, 0);
1608         WRITE_ONCE(pernet->add_addr_accept_max, 0);
1609         WRITE_ONCE(pernet->local_addr_max, 0);
1610         pernet->addrs = 0;
1611 }
1612
1613 static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info)
1614 {
1615         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1616         LIST_HEAD(free_list);
1617
1618         spin_lock_bh(&pernet->lock);
1619         list_splice_init(&pernet->local_addr_list, &free_list);
1620         __reset_counters(pernet);
1621         pernet->next_id = 1;
1622         bitmap_zero(pernet->id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
1623         spin_unlock_bh(&pernet->lock);
1624         mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list);
1625         synchronize_rcu();
1626         __flush_addrs(&free_list);
1627         return 0;
1628 }
1629
1630 static int mptcp_nl_fill_addr(struct sk_buff *skb,
1631                               struct mptcp_pm_addr_entry *entry)
1632 {
1633         struct mptcp_addr_info *addr = &entry->addr;
1634         struct nlattr *attr;
1635
1636         attr = nla_nest_start(skb, MPTCP_PM_ATTR_ADDR);
1637         if (!attr)
1638                 return -EMSGSIZE;
1639
1640         if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_FAMILY, addr->family))
1641                 goto nla_put_failure;
1642         if (nla_put_u16(skb, MPTCP_PM_ADDR_ATTR_PORT, ntohs(addr->port)))
1643                 goto nla_put_failure;
1644         if (nla_put_u8(skb, MPTCP_PM_ADDR_ATTR_ID, addr->id))
1645                 goto nla_put_failure;
1646         if (nla_put_u32(skb, MPTCP_PM_ADDR_ATTR_FLAGS, entry->flags))
1647                 goto nla_put_failure;
1648         if (entry->ifindex &&
1649             nla_put_s32(skb, MPTCP_PM_ADDR_ATTR_IF_IDX, entry->ifindex))
1650                 goto nla_put_failure;
1651
1652         if (addr->family == AF_INET &&
1653             nla_put_in_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR4,
1654                             addr->addr.s_addr))
1655                 goto nla_put_failure;
1656 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1657         else if (addr->family == AF_INET6 &&
1658                  nla_put_in6_addr(skb, MPTCP_PM_ADDR_ATTR_ADDR6, &addr->addr6))
1659                 goto nla_put_failure;
1660 #endif
1661         nla_nest_end(skb, attr);
1662         return 0;
1663
1664 nla_put_failure:
1665         nla_nest_cancel(skb, attr);
1666         return -EMSGSIZE;
1667 }
1668
1669 static int mptcp_nl_cmd_get_addr(struct sk_buff *skb, struct genl_info *info)
1670 {
1671         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1672         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1673         struct mptcp_pm_addr_entry addr, *entry;
1674         struct sk_buff *msg;
1675         void *reply;
1676         int ret;
1677
1678         ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1679         if (ret < 0)
1680                 return ret;
1681
1682         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1683         if (!msg)
1684                 return -ENOMEM;
1685
1686         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1687                                   info->genlhdr->cmd);
1688         if (!reply) {
1689                 GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1690                 ret = -EMSGSIZE;
1691                 goto fail;
1692         }
1693
1694         spin_lock_bh(&pernet->lock);
1695         entry = __lookup_addr_by_id(pernet, addr.addr.id);
1696         if (!entry) {
1697                 GENL_SET_ERR_MSG(info, "address not found");
1698                 ret = -EINVAL;
1699                 goto unlock_fail;
1700         }
1701
1702         ret = mptcp_nl_fill_addr(msg, entry);
1703         if (ret)
1704                 goto unlock_fail;
1705
1706         genlmsg_end(msg, reply);
1707         ret = genlmsg_reply(msg, info);
1708         spin_unlock_bh(&pernet->lock);
1709         return ret;
1710
1711 unlock_fail:
1712         spin_unlock_bh(&pernet->lock);
1713
1714 fail:
1715         nlmsg_free(msg);
1716         return ret;
1717 }
1718
1719 static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
1720                                    struct netlink_callback *cb)
1721 {
1722         struct net *net = sock_net(msg->sk);
1723         struct mptcp_pm_addr_entry *entry;
1724         struct pm_nl_pernet *pernet;
1725         int id = cb->args[0];
1726         void *hdr;
1727         int i;
1728
1729         pernet = pm_nl_get_pernet(net);
1730
1731         spin_lock_bh(&pernet->lock);
1732         for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {
1733                 if (test_bit(i, pernet->id_bitmap)) {
1734                         entry = __lookup_addr_by_id(pernet, i);
1735                         if (!entry)
1736                                 break;
1737
1738                         if (entry->addr.id <= id)
1739                                 continue;
1740
1741                         hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
1742                                           cb->nlh->nlmsg_seq, &mptcp_genl_family,
1743                                           NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
1744                         if (!hdr)
1745                                 break;
1746
1747                         if (mptcp_nl_fill_addr(msg, entry) < 0) {
1748                                 genlmsg_cancel(msg, hdr);
1749                                 break;
1750                         }
1751
1752                         id = entry->addr.id;
1753                         genlmsg_end(msg, hdr);
1754                 }
1755         }
1756         spin_unlock_bh(&pernet->lock);
1757
1758         cb->args[0] = id;
1759         return msg->len;
1760 }
1761
1762 static int parse_limit(struct genl_info *info, int id, unsigned int *limit)
1763 {
1764         struct nlattr *attr = info->attrs[id];
1765
1766         if (!attr)
1767                 return 0;
1768
1769         *limit = nla_get_u32(attr);
1770         if (*limit > MPTCP_PM_ADDR_MAX) {
1771                 GENL_SET_ERR_MSG(info, "limit greater than maximum");
1772                 return -EINVAL;
1773         }
1774         return 0;
1775 }
1776
1777 static int
1778 mptcp_nl_cmd_set_limits(struct sk_buff *skb, struct genl_info *info)
1779 {
1780         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1781         unsigned int rcv_addrs, subflows;
1782         int ret;
1783
1784         spin_lock_bh(&pernet->lock);
1785         rcv_addrs = pernet->add_addr_accept_max;
1786         ret = parse_limit(info, MPTCP_PM_ATTR_RCV_ADD_ADDRS, &rcv_addrs);
1787         if (ret)
1788                 goto unlock;
1789
1790         subflows = pernet->subflows_max;
1791         ret = parse_limit(info, MPTCP_PM_ATTR_SUBFLOWS, &subflows);
1792         if (ret)
1793                 goto unlock;
1794
1795         WRITE_ONCE(pernet->add_addr_accept_max, rcv_addrs);
1796         WRITE_ONCE(pernet->subflows_max, subflows);
1797
1798 unlock:
1799         spin_unlock_bh(&pernet->lock);
1800         return ret;
1801 }
1802
1803 static int
1804 mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
1805 {
1806         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1807         struct sk_buff *msg;
1808         void *reply;
1809
1810         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1811         if (!msg)
1812                 return -ENOMEM;
1813
1814         reply = genlmsg_put_reply(msg, info, &mptcp_genl_family, 0,
1815                                   MPTCP_PM_CMD_GET_LIMITS);
1816         if (!reply)
1817                 goto fail;
1818
1819         if (nla_put_u32(msg, MPTCP_PM_ATTR_RCV_ADD_ADDRS,
1820                         READ_ONCE(pernet->add_addr_accept_max)))
1821                 goto fail;
1822
1823         if (nla_put_u32(msg, MPTCP_PM_ATTR_SUBFLOWS,
1824                         READ_ONCE(pernet->subflows_max)))
1825                 goto fail;
1826
1827         genlmsg_end(msg, reply);
1828         return genlmsg_reply(msg, info);
1829
1830 fail:
1831         GENL_SET_ERR_MSG(info, "not enough space in Netlink message");
1832         nlmsg_free(msg);
1833         return -EMSGSIZE;
1834 }
1835
1836 static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
1837                                  struct mptcp_addr_info *addr)
1838 {
1839         struct mptcp_rm_list list = { .nr = 0 };
1840
1841         list.ids[list.nr++] = addr->id;
1842
1843         spin_lock_bh(&msk->pm.lock);
1844         mptcp_pm_nl_rm_subflow_received(msk, &list);
1845         mptcp_pm_create_subflow_or_signal_addr(msk);
1846         spin_unlock_bh(&msk->pm.lock);
1847 }
1848
1849 static int mptcp_nl_set_flags(struct net *net,
1850                               struct mptcp_addr_info *addr,
1851                               u8 bkup, u8 changed)
1852 {
1853         long s_slot = 0, s_num = 0;
1854         struct mptcp_sock *msk;
1855         int ret = -EINVAL;
1856
1857         while ((msk = mptcp_token_iter_next(net, &s_slot, &s_num)) != NULL) {
1858                 struct sock *sk = (struct sock *)msk;
1859
1860                 if (list_empty(&msk->conn_list) || mptcp_pm_is_userspace(msk))
1861                         goto next;
1862
1863                 lock_sock(sk);
1864                 if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
1865                         ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, NULL, bkup);
1866                 if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
1867                         mptcp_pm_nl_fullmesh(msk, addr);
1868                 release_sock(sk);
1869
1870 next:
1871                 sock_put(sk);
1872                 cond_resched();
1873         }
1874
1875         return ret;
1876 }
1877
1878 static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
1879 {
1880         struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
1881         struct mptcp_pm_addr_entry remote = { .addr = { .family = AF_UNSPEC }, };
1882         struct nlattr *attr_rem = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
1883         struct nlattr *token = info->attrs[MPTCP_PM_ATTR_TOKEN];
1884         struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
1885         struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
1886         u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
1887                            MPTCP_PM_ADDR_FLAG_FULLMESH;
1888         struct net *net = sock_net(skb->sk);
1889         u8 bkup = 0, lookup_by_id = 0;
1890         int ret;
1891
1892         ret = mptcp_pm_parse_entry(attr, info, false, &addr);
1893         if (ret < 0)
1894                 return ret;
1895
1896         if (attr_rem) {
1897                 ret = mptcp_pm_parse_entry(attr_rem, info, false, &remote);
1898                 if (ret < 0)
1899                         return ret;
1900         }
1901
1902         if (addr.flags & MPTCP_PM_ADDR_FLAG_BACKUP)
1903                 bkup = 1;
1904         if (addr.addr.family == AF_UNSPEC) {
1905                 lookup_by_id = 1;
1906                 if (!addr.addr.id)
1907                         return -EOPNOTSUPP;
1908         }
1909
1910         if (token)
1911                 return mptcp_userspace_pm_set_flags(sock_net(skb->sk),
1912                                                     token, &addr, &remote, bkup);
1913
1914         spin_lock_bh(&pernet->lock);
1915         entry = __lookup_addr(pernet, &addr.addr, lookup_by_id);
1916         if (!entry) {
1917                 spin_unlock_bh(&pernet->lock);
1918                 return -EINVAL;
1919         }
1920         if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
1921             (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
1922                 spin_unlock_bh(&pernet->lock);
1923                 return -EINVAL;
1924         }
1925
1926         changed = (addr.flags ^ entry->flags) & mask;
1927         entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
1928         addr = *entry;
1929         spin_unlock_bh(&pernet->lock);
1930
1931         mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
1932         return 0;
1933 }
1934
1935 static void mptcp_nl_mcast_send(struct net *net, struct sk_buff *nlskb, gfp_t gfp)
1936 {
1937         genlmsg_multicast_netns(&mptcp_genl_family, net,
1938                                 nlskb, 0, MPTCP_PM_EV_GRP_OFFSET, gfp);
1939 }
1940
1941 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk)
1942 {
1943         return genl_has_listeners(&mptcp_genl_family,
1944                                   sock_net((const struct sock *)msk),
1945                                   MPTCP_PM_EV_GRP_OFFSET);
1946 }
1947
1948 static int mptcp_event_add_subflow(struct sk_buff *skb, const struct sock *ssk)
1949 {
1950         const struct inet_sock *issk = inet_sk(ssk);
1951         const struct mptcp_subflow_context *sf;
1952
1953         if (nla_put_u16(skb, MPTCP_ATTR_FAMILY, ssk->sk_family))
1954                 return -EMSGSIZE;
1955
1956         switch (ssk->sk_family) {
1957         case AF_INET:
1958                 if (nla_put_in_addr(skb, MPTCP_ATTR_SADDR4, issk->inet_saddr))
1959                         return -EMSGSIZE;
1960                 if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, issk->inet_daddr))
1961                         return -EMSGSIZE;
1962                 break;
1963 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
1964         case AF_INET6: {
1965                 const struct ipv6_pinfo *np = inet6_sk(ssk);
1966
1967                 if (nla_put_in6_addr(skb, MPTCP_ATTR_SADDR6, &np->saddr))
1968                         return -EMSGSIZE;
1969                 if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &ssk->sk_v6_daddr))
1970                         return -EMSGSIZE;
1971                 break;
1972         }
1973 #endif
1974         default:
1975                 WARN_ON_ONCE(1);
1976                 return -EMSGSIZE;
1977         }
1978
1979         if (nla_put_be16(skb, MPTCP_ATTR_SPORT, issk->inet_sport))
1980                 return -EMSGSIZE;
1981         if (nla_put_be16(skb, MPTCP_ATTR_DPORT, issk->inet_dport))
1982                 return -EMSGSIZE;
1983
1984         sf = mptcp_subflow_ctx(ssk);
1985         if (WARN_ON_ONCE(!sf))
1986                 return -EINVAL;
1987
1988         if (nla_put_u8(skb, MPTCP_ATTR_LOC_ID, sf->local_id))
1989                 return -EMSGSIZE;
1990
1991         if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, sf->remote_id))
1992                 return -EMSGSIZE;
1993
1994         return 0;
1995 }
1996
1997 static int mptcp_event_put_token_and_ssk(struct sk_buff *skb,
1998                                          const struct mptcp_sock *msk,
1999                                          const struct sock *ssk)
2000 {
2001         const struct sock *sk = (const struct sock *)msk;
2002         const struct mptcp_subflow_context *sf;
2003         u8 sk_err;
2004
2005         if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2006                 return -EMSGSIZE;
2007
2008         if (mptcp_event_add_subflow(skb, ssk))
2009                 return -EMSGSIZE;
2010
2011         sf = mptcp_subflow_ctx(ssk);
2012         if (WARN_ON_ONCE(!sf))
2013                 return -EINVAL;
2014
2015         if (nla_put_u8(skb, MPTCP_ATTR_BACKUP, sf->backup))
2016                 return -EMSGSIZE;
2017
2018         if (ssk->sk_bound_dev_if &&
2019             nla_put_s32(skb, MPTCP_ATTR_IF_IDX, ssk->sk_bound_dev_if))
2020                 return -EMSGSIZE;
2021
2022         sk_err = ssk->sk_err;
2023         if (sk_err && sk->sk_state == TCP_ESTABLISHED &&
2024             nla_put_u8(skb, MPTCP_ATTR_ERROR, sk_err))
2025                 return -EMSGSIZE;
2026
2027         return 0;
2028 }
2029
2030 static int mptcp_event_sub_established(struct sk_buff *skb,
2031                                        const struct mptcp_sock *msk,
2032                                        const struct sock *ssk)
2033 {
2034         return mptcp_event_put_token_and_ssk(skb, msk, ssk);
2035 }
2036
2037 static int mptcp_event_sub_closed(struct sk_buff *skb,
2038                                   const struct mptcp_sock *msk,
2039                                   const struct sock *ssk)
2040 {
2041         const struct mptcp_subflow_context *sf;
2042
2043         if (mptcp_event_put_token_and_ssk(skb, msk, ssk))
2044                 return -EMSGSIZE;
2045
2046         sf = mptcp_subflow_ctx(ssk);
2047         if (!sf->reset_seen)
2048                 return 0;
2049
2050         if (nla_put_u32(skb, MPTCP_ATTR_RESET_REASON, sf->reset_reason))
2051                 return -EMSGSIZE;
2052
2053         if (nla_put_u32(skb, MPTCP_ATTR_RESET_FLAGS, sf->reset_transient))
2054                 return -EMSGSIZE;
2055
2056         return 0;
2057 }
2058
2059 static int mptcp_event_created(struct sk_buff *skb,
2060                                const struct mptcp_sock *msk,
2061                                const struct sock *ssk)
2062 {
2063         int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token);
2064
2065         if (err)
2066                 return err;
2067
2068         if (nla_put_u8(skb, MPTCP_ATTR_SERVER_SIDE, READ_ONCE(msk->pm.server_side)))
2069                 return -EMSGSIZE;
2070
2071         return mptcp_event_add_subflow(skb, ssk);
2072 }
2073
2074 void mptcp_event_addr_removed(const struct mptcp_sock *msk, uint8_t id)
2075 {
2076         struct net *net = sock_net((const struct sock *)msk);
2077         struct nlmsghdr *nlh;
2078         struct sk_buff *skb;
2079
2080         if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2081                 return;
2082
2083         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
2084         if (!skb)
2085                 return;
2086
2087         nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, MPTCP_EVENT_REMOVED);
2088         if (!nlh)
2089                 goto nla_put_failure;
2090
2091         if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2092                 goto nla_put_failure;
2093
2094         if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, id))
2095                 goto nla_put_failure;
2096
2097         genlmsg_end(skb, nlh);
2098         mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
2099         return;
2100
2101 nla_put_failure:
2102         kfree_skb(skb);
2103 }
2104
2105 void mptcp_event_addr_announced(const struct sock *ssk,
2106                                 const struct mptcp_addr_info *info)
2107 {
2108         struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
2109         struct mptcp_sock *msk = mptcp_sk(subflow->conn);
2110         struct net *net = sock_net(ssk);
2111         struct nlmsghdr *nlh;
2112         struct sk_buff *skb;
2113
2114         if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2115                 return;
2116
2117         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
2118         if (!skb)
2119                 return;
2120
2121         nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0,
2122                           MPTCP_EVENT_ANNOUNCED);
2123         if (!nlh)
2124                 goto nla_put_failure;
2125
2126         if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
2127                 goto nla_put_failure;
2128
2129         if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, info->id))
2130                 goto nla_put_failure;
2131
2132         if (nla_put_be16(skb, MPTCP_ATTR_DPORT,
2133                          info->port == 0 ?
2134                          inet_sk(ssk)->inet_dport :
2135                          info->port))
2136                 goto nla_put_failure;
2137
2138         switch (info->family) {
2139         case AF_INET:
2140                 if (nla_put_in_addr(skb, MPTCP_ATTR_DADDR4, info->addr.s_addr))
2141                         goto nla_put_failure;
2142                 break;
2143 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
2144         case AF_INET6:
2145                 if (nla_put_in6_addr(skb, MPTCP_ATTR_DADDR6, &info->addr6))
2146                         goto nla_put_failure;
2147                 break;
2148 #endif
2149         default:
2150                 WARN_ON_ONCE(1);
2151                 goto nla_put_failure;
2152         }
2153
2154         genlmsg_end(skb, nlh);
2155         mptcp_nl_mcast_send(net, skb, GFP_ATOMIC);
2156         return;
2157
2158 nla_put_failure:
2159         kfree_skb(skb);
2160 }
2161
2162 void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
2163                  const struct sock *ssk, gfp_t gfp)
2164 {
2165         struct net *net = sock_net((const struct sock *)msk);
2166         struct nlmsghdr *nlh;
2167         struct sk_buff *skb;
2168
2169         if (!genl_has_listeners(&mptcp_genl_family, net, MPTCP_PM_EV_GRP_OFFSET))
2170                 return;
2171
2172         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
2173         if (!skb)
2174                 return;
2175
2176         nlh = genlmsg_put(skb, 0, 0, &mptcp_genl_family, 0, type);
2177         if (!nlh)
2178                 goto nla_put_failure;
2179
2180         switch (type) {
2181         case MPTCP_EVENT_UNSPEC:
2182                 WARN_ON_ONCE(1);
2183                 break;
2184         case MPTCP_EVENT_CREATED:
2185         case MPTCP_EVENT_ESTABLISHED:
2186                 if (mptcp_event_created(skb, msk, ssk) < 0)
2187                         goto nla_put_failure;
2188                 break;
2189         case MPTCP_EVENT_CLOSED:
2190                 if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token) < 0)
2191                         goto nla_put_failure;
2192                 break;
2193         case MPTCP_EVENT_ANNOUNCED:
2194         case MPTCP_EVENT_REMOVED:
2195                 /* call mptcp_event_addr_announced()/removed instead */
2196                 WARN_ON_ONCE(1);
2197                 break;
2198         case MPTCP_EVENT_SUB_ESTABLISHED:
2199         case MPTCP_EVENT_SUB_PRIORITY:
2200                 if (mptcp_event_sub_established(skb, msk, ssk) < 0)
2201                         goto nla_put_failure;
2202                 break;
2203         case MPTCP_EVENT_SUB_CLOSED:
2204                 if (mptcp_event_sub_closed(skb, msk, ssk) < 0)
2205                         goto nla_put_failure;
2206                 break;
2207         }
2208
2209         genlmsg_end(skb, nlh);
2210         mptcp_nl_mcast_send(net, skb, gfp);
2211         return;
2212
2213 nla_put_failure:
2214         kfree_skb(skb);
2215 }
2216
2217 static const struct genl_small_ops mptcp_pm_ops[] = {
2218         {
2219                 .cmd    = MPTCP_PM_CMD_ADD_ADDR,
2220                 .doit   = mptcp_nl_cmd_add_addr,
2221                 .flags  = GENL_ADMIN_PERM,
2222         },
2223         {
2224                 .cmd    = MPTCP_PM_CMD_DEL_ADDR,
2225                 .doit   = mptcp_nl_cmd_del_addr,
2226                 .flags  = GENL_ADMIN_PERM,
2227         },
2228         {
2229                 .cmd    = MPTCP_PM_CMD_FLUSH_ADDRS,
2230                 .doit   = mptcp_nl_cmd_flush_addrs,
2231                 .flags  = GENL_ADMIN_PERM,
2232         },
2233         {
2234                 .cmd    = MPTCP_PM_CMD_GET_ADDR,
2235                 .doit   = mptcp_nl_cmd_get_addr,
2236                 .dumpit   = mptcp_nl_cmd_dump_addrs,
2237         },
2238         {
2239                 .cmd    = MPTCP_PM_CMD_SET_LIMITS,
2240                 .doit   = mptcp_nl_cmd_set_limits,
2241                 .flags  = GENL_ADMIN_PERM,
2242         },
2243         {
2244                 .cmd    = MPTCP_PM_CMD_GET_LIMITS,
2245                 .doit   = mptcp_nl_cmd_get_limits,
2246         },
2247         {
2248                 .cmd    = MPTCP_PM_CMD_SET_FLAGS,
2249                 .doit   = mptcp_nl_cmd_set_flags,
2250                 .flags  = GENL_ADMIN_PERM,
2251         },
2252         {
2253                 .cmd    = MPTCP_PM_CMD_ANNOUNCE,
2254                 .doit   = mptcp_nl_cmd_announce,
2255                 .flags  = GENL_ADMIN_PERM,
2256         },
2257         {
2258                 .cmd    = MPTCP_PM_CMD_REMOVE,
2259                 .doit   = mptcp_nl_cmd_remove,
2260                 .flags  = GENL_ADMIN_PERM,
2261         },
2262         {
2263                 .cmd    = MPTCP_PM_CMD_SUBFLOW_CREATE,
2264                 .doit   = mptcp_nl_cmd_sf_create,
2265                 .flags  = GENL_ADMIN_PERM,
2266         },
2267         {
2268                 .cmd    = MPTCP_PM_CMD_SUBFLOW_DESTROY,
2269                 .doit   = mptcp_nl_cmd_sf_destroy,
2270                 .flags  = GENL_ADMIN_PERM,
2271         },
2272 };
2273
2274 static struct genl_family mptcp_genl_family __ro_after_init = {
2275         .name           = MPTCP_PM_NAME,
2276         .version        = MPTCP_PM_VER,
2277         .maxattr        = MPTCP_PM_ATTR_MAX,
2278         .policy         = mptcp_pm_policy,
2279         .netnsok        = true,
2280         .module         = THIS_MODULE,
2281         .small_ops      = mptcp_pm_ops,
2282         .n_small_ops    = ARRAY_SIZE(mptcp_pm_ops),
2283         .mcgrps         = mptcp_pm_mcgrps,
2284         .n_mcgrps       = ARRAY_SIZE(mptcp_pm_mcgrps),
2285 };
2286
2287 static int __net_init pm_nl_init_net(struct net *net)
2288 {
2289         struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
2290
2291         INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
2292
2293         /* Cit. 2 subflows ought to be enough for anybody. */
2294         pernet->subflows_max = 2;
2295         pernet->next_id = 1;
2296         pernet->stale_loss_cnt = 4;
2297         spin_lock_init(&pernet->lock);
2298
2299         /* No need to initialize other pernet fields, the struct is zeroed at
2300          * allocation time.
2301          */
2302
2303         return 0;
2304 }
2305
2306 static void __net_exit pm_nl_exit_net(struct list_head *net_list)
2307 {
2308         struct net *net;
2309
2310         list_for_each_entry(net, net_list, exit_list) {
2311                 struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
2312
2313                 /* net is removed from namespace list, can't race with
2314                  * other modifiers, also netns core already waited for a
2315                  * RCU grace period.
2316                  */
2317                 __flush_addrs(&pernet->local_addr_list);
2318         }
2319 }
2320
2321 static struct pernet_operations mptcp_pm_pernet_ops = {
2322         .init = pm_nl_init_net,
2323         .exit_batch = pm_nl_exit_net,
2324         .id = &pm_nl_pernet_id,
2325         .size = sizeof(struct pm_nl_pernet),
2326 };
2327
2328 void __init mptcp_pm_nl_init(void)
2329 {
2330         if (register_pernet_subsys(&mptcp_pm_pernet_ops) < 0)
2331                 panic("Failed to register MPTCP PM pernet subsystem.\n");
2332
2333         if (genl_register_family(&mptcp_genl_family))
2334                 panic("Failed to register MPTCP PM netlink family\n");
2335 }