net/ipv6/ip6_flowlabel.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      ip6_flowlabel.c         IPv6 flowlabel manager.
   4  *
   5  *      Authors:        Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  */
   7
   8 #include <linux/capability.h>
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/net.h>
  13 #include <linux/netdevice.h>
  14 #include <linux/in6.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/slab.h>
  18 #include <linux/export.h>
  19 #include <linux/pid_namespace.h>
  20 #include <linux/jump_label_ratelimit.h>
  21
  22 #include <net/net_namespace.h>
  23 #include <net/sock.h>
  24
  25 #include <net/ipv6.h>
  26 #include <net/rawv6.h>
  27 #include <net/transp_v6.h>
  28
  29 #include <linux/uaccess.h>
  30
  31 #define FL_MIN_LINGER   6       /* Minimal linger. It is set to 6sec specified
  32                                    in old IPv6 RFC. Well, it was reasonable value.
  33                                  */
  34 #define FL_MAX_LINGER   150     /* Maximal linger timeout */
  35
  36 /* FL hash table */
  37
  38 #define FL_MAX_PER_SOCK 32
  39 #define FL_MAX_SIZE     4096
  40 #define FL_HASH_MASK    255
  41 #define FL_HASH(l)      (ntohl(l)&FL_HASH_MASK)
  42
  43 static atomic_t fl_size = ATOMIC_INIT(0);
  44 static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
  45
  46 static void ip6_fl_gc(struct timer_list *unused);
  47 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc);
  48
  49 /* FL hash table lock: it protects only of GC */
  50
  51 static DEFINE_SPINLOCK(ip6_fl_lock);
  52
  53 /* Big socket sock */
  54
  55 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
  56
  57 DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
  58 EXPORT_SYMBOL(ipv6_flowlabel_exclusive);
  59
  60 #define for_each_fl_rcu(hash, fl)                               \
  61         for (fl = rcu_dereference(fl_ht[(hash)]);               \
  62              fl != NULL;                                        \
  63              fl = rcu_dereference(fl->next))
  64 #define for_each_fl_continue_rcu(fl)                            \
  65         for (fl = rcu_dereference(fl->next);                    \
  66              fl != NULL;                                        \
  67              fl = rcu_dereference(fl->next))
  68
  69 #define for_each_sk_fl_rcu(np, sfl)                             \
  70         for (sfl = rcu_dereference(np->ipv6_fl_list);   \
  71              sfl != NULL;                                       \
  72              sfl = rcu_dereference(sfl->next))
  73
  74 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
  75 {
  76         struct ip6_flowlabel *fl;
  77
  78         for_each_fl_rcu(FL_HASH(label), fl) {
  79                 if (fl->label == label && net_eq(fl->fl_net, net))
  80                         return fl;
  81         }
  82         return NULL;
  83 }
  84
  85 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
  86 {
  87         struct ip6_flowlabel *fl;
  88
  89         rcu_read_lock();
  90         fl = __fl_lookup(net, label);
  91         if (fl && !atomic_inc_not_zero(&fl->users))
  92                 fl = NULL;
  93         rcu_read_unlock();
  94         return fl;
  95 }
  96
  97 static bool fl_shared_exclusive(struct ip6_flowlabel *fl)
  98 {
  99         return fl->share == IPV6_FL_S_EXCL ||
 100                fl->share == IPV6_FL_S_PROCESS ||
 101                fl->share == IPV6_FL_S_USER;
 102 }
 103
 104 static void fl_free_rcu(struct rcu_head *head)
 105 {
 106         struct ip6_flowlabel *fl = container_of(head, struct ip6_flowlabel, rcu);
 107
 108         if (fl->share == IPV6_FL_S_PROCESS)
 109                 put_pid(fl->owner.pid);
 110         kfree(fl->opt);
 111         kfree(fl);
 112 }
 113
 114
 115 static void fl_free(struct ip6_flowlabel *fl)
 116 {
 117         if (!fl)
 118                 return;
 119
 120         if (fl_shared_exclusive(fl) || fl->opt)
 121                 static_branch_slow_dec_deferred(&ipv6_flowlabel_exclusive);
 122
 123         call_rcu(&fl->rcu, fl_free_rcu);
 124 }
 125
 126 static void fl_release(struct ip6_flowlabel *fl)
 127 {
 128         spin_lock_bh(&ip6_fl_lock);
 129
 130         fl->lastuse = jiffies;
 131         if (atomic_dec_and_test(&fl->users)) {
 132                 unsigned long ttd = fl->lastuse + fl->linger;
 133                 if (time_after(ttd, fl->expires))
 134                         fl->expires = ttd;
 135                 ttd = fl->expires;
 136                 if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
 137                         struct ipv6_txoptions *opt = fl->opt;
 138                         fl->opt = NULL;
 139                         kfree(opt);
 140                 }
 141                 if (!timer_pending(&ip6_fl_gc_timer) ||
 142                     time_after(ip6_fl_gc_timer.expires, ttd))
 143                         mod_timer(&ip6_fl_gc_timer, ttd);
 144         }
 145         spin_unlock_bh(&ip6_fl_lock);
 146 }
 147
 148 static void ip6_fl_gc(struct timer_list *unused)
 149 {
 150         int i;
 151         unsigned long now = jiffies;
 152         unsigned long sched = 0;
 153
 154         spin_lock(&ip6_fl_lock);
 155
 156         for (i = 0; i <= FL_HASH_MASK; i++) {
 157                 struct ip6_flowlabel *fl;
 158                 struct ip6_flowlabel __rcu **flp;
 159
 160                 flp = &fl_ht[i];
 161                 while ((fl = rcu_dereference_protected(*flp,
 162                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 163                         if (atomic_read(&fl->users) == 0) {
 164                                 unsigned long ttd = fl->lastuse + fl->linger;
 165                                 if (time_after(ttd, fl->expires))
 166                                         fl->expires = ttd;
 167                                 ttd = fl->expires;
 168                                 if (time_after_eq(now, ttd)) {
 169                                         *flp = fl->next;
 170                                         fl_free(fl);
 171                                         atomic_dec(&fl_size);
 172                                         continue;
 173                                 }
 174                                 if (!sched || time_before(ttd, sched))
 175                                         sched = ttd;
 176                         }
 177                         flp = &fl->next;
 178                 }
 179         }
 180         if (!sched && atomic_read(&fl_size))
 181                 sched = now + FL_MAX_LINGER;
 182         if (sched) {
 183                 mod_timer(&ip6_fl_gc_timer, sched);
 184         }
 185         spin_unlock(&ip6_fl_lock);
 186 }
 187
 188 static void __net_exit ip6_fl_purge(struct net *net)
 189 {
 190         int i;
 191
 192         spin_lock_bh(&ip6_fl_lock);
 193         for (i = 0; i <= FL_HASH_MASK; i++) {
 194                 struct ip6_flowlabel *fl;
 195                 struct ip6_flowlabel __rcu **flp;
 196
 197                 flp = &fl_ht[i];
 198                 while ((fl = rcu_dereference_protected(*flp,
 199                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 200                         if (net_eq(fl->fl_net, net) &&
 201                             atomic_read(&fl->users) == 0) {
 202                                 *flp = fl->next;
 203                                 fl_free(fl);
 204                                 atomic_dec(&fl_size);
 205                                 continue;
 206                         }
 207                         flp = &fl->next;
 208                 }
 209         }
 210         spin_unlock_bh(&ip6_fl_lock);
 211 }
 212
 213 static struct ip6_flowlabel *fl_intern(struct net *net,
 214                                        struct ip6_flowlabel *fl, __be32 label)
 215 {
 216         struct ip6_flowlabel *lfl;
 217
 218         fl->label = label & IPV6_FLOWLABEL_MASK;
 219
 220         rcu_read_lock();
 221         spin_lock_bh(&ip6_fl_lock);
 222         if (label == 0) {
 223                 for (;;) {
 224                         fl->label = htonl(get_random_u32())&IPV6_FLOWLABEL_MASK;
 225                         if (fl->label) {
 226                                 lfl = __fl_lookup(net, fl->label);
 227                                 if (!lfl)
 228                                         break;
 229                         }
 230                 }
 231         } else {
 232                 /*
 233                  * we dropper the ip6_fl_lock, so this entry could reappear
 234                  * and we need to recheck with it.
 235                  *
 236                  * OTOH no need to search the active socket first, like it is
 237                  * done in ipv6_flowlabel_opt - sock is locked, so new entry
 238                  * with the same label can only appear on another sock
 239                  */
 240                 lfl = __fl_lookup(net, fl->label);
 241                 if (lfl) {
 242                         atomic_inc(&lfl->users);
 243                         spin_unlock_bh(&ip6_fl_lock);
 244                         rcu_read_unlock();
 245                         return lfl;
 246                 }
 247         }
 248
 249         fl->lastuse = jiffies;
 250         fl->next = fl_ht[FL_HASH(fl->label)];
 251         rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
 252         atomic_inc(&fl_size);
 253         spin_unlock_bh(&ip6_fl_lock);
 254         rcu_read_unlock();
 255         return NULL;
 256 }
 257
 258
 259
 260 /* Socket flowlabel lists */
 261
 262 struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)
 263 {
 264         struct ipv6_fl_socklist *sfl;
 265         struct ipv6_pinfo *np = inet6_sk(sk);
 266
 267         label &= IPV6_FLOWLABEL_MASK;
 268
 269         rcu_read_lock();
 270         for_each_sk_fl_rcu(np, sfl) {
 271                 struct ip6_flowlabel *fl = sfl->fl;
 272
 273                 if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
 274                         fl->lastuse = jiffies;
 275                         rcu_read_unlock();
 276                         return fl;
 277                 }
 278         }
 279         rcu_read_unlock();
 280         return NULL;
 281 }
 282 EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
 283
 284 void fl6_free_socklist(struct sock *sk)
 285 {
 286         struct ipv6_pinfo *np = inet6_sk(sk);
 287         struct ipv6_fl_socklist *sfl;
 288
 289         if (!rcu_access_pointer(np->ipv6_fl_list))
 290                 return;
 291
 292         spin_lock_bh(&ip6_sk_fl_lock);
 293         while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
 294                                                 lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
 295                 np->ipv6_fl_list = sfl->next;
 296                 spin_unlock_bh(&ip6_sk_fl_lock);
 297
 298                 fl_release(sfl->fl);
 299                 kfree_rcu(sfl, rcu);
 300
 301                 spin_lock_bh(&ip6_sk_fl_lock);
 302         }
 303         spin_unlock_bh(&ip6_sk_fl_lock);
 304 }
 305
 306 /* Service routines */
 307
 308
 309 /*
 310    It is the only difficult place. flowlabel enforces equal headers
 311    before and including routing header, however user may supply options
 312    following rthdr.
 313  */
 314
 315 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
 316                                          struct ip6_flowlabel *fl,
 317                                          struct ipv6_txoptions *fopt)
 318 {
 319         struct ipv6_txoptions *fl_opt = fl->opt;
 320
 321         if (!fopt || fopt->opt_flen == 0)
 322                 return fl_opt;
 323
 324         if (fl_opt) {
 325                 opt_space->hopopt = fl_opt->hopopt;
 326                 opt_space->dst0opt = fl_opt->dst0opt;
 327                 opt_space->srcrt = fl_opt->srcrt;
 328                 opt_space->opt_nflen = fl_opt->opt_nflen;
 329         } else {
 330                 if (fopt->opt_nflen == 0)
 331                         return fopt;
 332                 opt_space->hopopt = NULL;
 333                 opt_space->dst0opt = NULL;
 334                 opt_space->srcrt = NULL;
 335                 opt_space->opt_nflen = 0;
 336         }
 337         opt_space->dst1opt = fopt->dst1opt;
 338         opt_space->opt_flen = fopt->opt_flen;
 339         opt_space->tot_len = fopt->tot_len;
 340         return opt_space;
 341 }
 342 EXPORT_SYMBOL_GPL(fl6_merge_options);
 343
 344 static unsigned long check_linger(unsigned long ttl)
 345 {
 346         if (ttl < FL_MIN_LINGER)
 347                 return FL_MIN_LINGER*HZ;
 348         if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
 349                 return 0;
 350         return ttl*HZ;
 351 }
 352
 353 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
 354 {
 355         linger = check_linger(linger);
 356         if (!linger)
 357                 return -EPERM;
 358         expires = check_linger(expires);
 359         if (!expires)
 360                 return -EPERM;
 361
 362         spin_lock_bh(&ip6_fl_lock);
 363         fl->lastuse = jiffies;
 364         if (time_before(fl->linger, linger))
 365                 fl->linger = linger;
 366         if (time_before(expires, fl->linger))
 367                 expires = fl->linger;
 368         if (time_before(fl->expires, fl->lastuse + expires))
 369                 fl->expires = fl->lastuse + expires;
 370         spin_unlock_bh(&ip6_fl_lock);
 371
 372         return 0;
 373 }
 374
 375 static struct ip6_flowlabel *
 376 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 377           sockptr_t optval, int optlen, int *err_p)
 378 {
 379         struct ip6_flowlabel *fl = NULL;
 380         int olen;
 381         int addr_type;
 382         int err;
 383
 384         olen = optlen - CMSG_ALIGN(sizeof(*freq));
 385         err = -EINVAL;
 386         if (olen > 64 * 1024)
 387                 goto done;
 388
 389         err = -ENOMEM;
 390         fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 391         if (!fl)
 392                 goto done;
 393
 394         if (olen > 0) {
 395                 struct msghdr msg;
 396                 struct flowi6 flowi6;
 397                 struct ipcm6_cookie ipc6;
 398
 399                 err = -ENOMEM;
 400                 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 401                 if (!fl->opt)
 402                         goto done;
 403
 404                 memset(fl->opt, 0, sizeof(*fl->opt));
 405                 fl->opt->tot_len = sizeof(*fl->opt) + olen;
 406                 err = -EFAULT;
 407                 if (copy_from_sockptr_offset(fl->opt + 1, optval,
 408                                 CMSG_ALIGN(sizeof(*freq)), olen))
 409                         goto done;
 410
 411                 msg.msg_controllen = olen;
 412                 msg.msg_control = (void *)(fl->opt+1);
 413                 memset(&flowi6, 0, sizeof(flowi6));
 414
 415                 ipc6.opt = fl->opt;
 416                 err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6);
 417                 if (err)
 418                         goto done;
 419                 err = -EINVAL;
 420                 if (fl->opt->opt_flen)
 421                         goto done;
 422                 if (fl->opt->opt_nflen == 0) {
 423                         kfree(fl->opt);
 424                         fl->opt = NULL;
 425                 }
 426         }
 427
 428         fl->fl_net = net;
 429         fl->expires = jiffies;
 430         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 431         if (err)
 432                 goto done;
 433         fl->share = freq->flr_share;
 434         addr_type = ipv6_addr_type(&freq->flr_dst);
 435         if ((addr_type & IPV6_ADDR_MAPPED) ||
 436             addr_type == IPV6_ADDR_ANY) {
 437                 err = -EINVAL;
 438                 goto done;
 439         }
 440         fl->dst = freq->flr_dst;
 441         atomic_set(&fl->users, 1);
 442         switch (fl->share) {
 443         case IPV6_FL_S_EXCL:
 444         case IPV6_FL_S_ANY:
 445                 break;
 446         case IPV6_FL_S_PROCESS:
 447                 fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 448                 break;
 449         case IPV6_FL_S_USER:
 450                 fl->owner.uid = current_euid();
 451                 break;
 452         default:
 453                 err = -EINVAL;
 454                 goto done;
 455         }
 456         if (fl_shared_exclusive(fl) || fl->opt) {
 457                 WRITE_ONCE(sock_net(sk)->ipv6.flowlabel_has_excl, 1);
 458                 static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
 459         }
 460         return fl;
 461
 462 done:
 463         if (fl) {
 464                 kfree(fl->opt);
 465                 kfree(fl);
 466         }
 467         *err_p = err;
 468         return NULL;
 469 }
 470
 471 static int mem_check(struct sock *sk)
 472 {
 473         struct ipv6_pinfo *np = inet6_sk(sk);
 474         struct ipv6_fl_socklist *sfl;
 475         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 476         int count = 0;
 477
 478         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 479                 return 0;
 480
 481         rcu_read_lock();
 482         for_each_sk_fl_rcu(np, sfl)
 483                 count++;
 484         rcu_read_unlock();
 485
 486         if (room <= 0 ||
 487             ((count >= FL_MAX_PER_SOCK ||
 488               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 489              !capable(CAP_NET_ADMIN)))
 490                 return -ENOBUFS;
 491
 492         return 0;
 493 }
 494
 495 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 496                 struct ip6_flowlabel *fl)
 497 {
 498         spin_lock_bh(&ip6_sk_fl_lock);
 499         sfl->fl = fl;
 500         sfl->next = np->ipv6_fl_list;
 501         rcu_assign_pointer(np->ipv6_fl_list, sfl);
 502         spin_unlock_bh(&ip6_sk_fl_lock);
 503 }
 504
 505 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 506                            int flags)
 507 {
 508         struct ipv6_pinfo *np = inet6_sk(sk);
 509         struct ipv6_fl_socklist *sfl;
 510
 511         if (flags & IPV6_FL_F_REMOTE) {
 512                 freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 513                 return 0;
 514         }
 515
 516         if (np->repflow) {
 517                 freq->flr_label = np->flow_label;
 518                 return 0;
 519         }
 520
 521         rcu_read_lock();
 522
 523         for_each_sk_fl_rcu(np, sfl) {
 524                 if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 525                         spin_lock_bh(&ip6_fl_lock);
 526                         freq->flr_label = sfl->fl->label;
 527                         freq->flr_dst = sfl->fl->dst;
 528                         freq->flr_share = sfl->fl->share;
 529                         freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 530                         freq->flr_linger = sfl->fl->linger / HZ;
 531
 532                         spin_unlock_bh(&ip6_fl_lock);
 533                         rcu_read_unlock();
 534                         return 0;
 535                 }
 536         }
 537         rcu_read_unlock();
 538
 539         return -ENOENT;
 540 }
 541
 542 #define socklist_dereference(__sflp) \
 543         rcu_dereference_protected(__sflp, lockdep_is_held(&ip6_sk_fl_lock))
 544
 545 static int ipv6_flowlabel_put(struct sock *sk, struct in6_flowlabel_req *freq)
 546 {
 547         struct ipv6_pinfo *np = inet6_sk(sk);
 548         struct ipv6_fl_socklist __rcu **sflp;
 549         struct ipv6_fl_socklist *sfl;
 550
 551         if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 552                 if (sk->sk_protocol != IPPROTO_TCP)
 553                         return -ENOPROTOOPT;
 554                 if (!np->repflow)
 555                         return -ESRCH;
 556                 np->flow_label = 0;
 557                 np->repflow = 0;
 558                 return 0;
 559         }
 560
 561         spin_lock_bh(&ip6_sk_fl_lock);
 562         for (sflp = &np->ipv6_fl_list;
 563              (sfl = socklist_dereference(*sflp)) != NULL;
 564              sflp = &sfl->next) {
 565                 if (sfl->fl->label == freq->flr_label)
 566                         goto found;
 567         }
 568         spin_unlock_bh(&ip6_sk_fl_lock);
 569         return -ESRCH;
 570 found:
 571         if (freq->flr_label == (np->flow_label & IPV6_FLOWLABEL_MASK))
 572                 np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 573         *sflp = sfl->next;
 574         spin_unlock_bh(&ip6_sk_fl_lock);
 575         fl_release(sfl->fl);
 576         kfree_rcu(sfl, rcu);
 577         return 0;
 578 }
 579
 580 static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
 581 {
 582         struct ipv6_pinfo *np = inet6_sk(sk);
 583         struct net *net = sock_net(sk);
 584         struct ipv6_fl_socklist *sfl;
 585         int err;
 586
 587         rcu_read_lock();
 588         for_each_sk_fl_rcu(np, sfl) {
 589                 if (sfl->fl->label == freq->flr_label) {
 590                         err = fl6_renew(sfl->fl, freq->flr_linger,
 591                                         freq->flr_expires);
 592                         rcu_read_unlock();
 593                         return err;
 594                 }
 595         }
 596         rcu_read_unlock();
 597
 598         if (freq->flr_share == IPV6_FL_S_NONE &&
 599             ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 600                 struct ip6_flowlabel *fl = fl_lookup(net, freq->flr_label);
 601
 602                 if (fl) {
 603                         err = fl6_renew(fl, freq->flr_linger,
 604                                         freq->flr_expires);
 605                         fl_release(fl);
 606                         return err;
 607                 }
 608         }
 609         return -ESRCH;
 610 }
 611
 612 static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 613                 sockptr_t optval, int optlen)
 614 {
 615         struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
 616         struct ip6_flowlabel *fl, *fl1 = NULL;
 617         struct ipv6_pinfo *np = inet6_sk(sk);
 618         struct net *net = sock_net(sk);
 619         int err;
 620
 621         if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 622                 if (net->ipv6.sysctl.flowlabel_consistency) {
 623                         net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 624                         return -EPERM;
 625                 }
 626
 627                 if (sk->sk_protocol != IPPROTO_TCP)
 628                         return -ENOPROTOOPT;
 629                 np->repflow = 1;
 630                 return 0;
 631         }
 632
 633         if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
 634                 return -EINVAL;
 635         if (net->ipv6.sysctl.flowlabel_state_ranges &&
 636             (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 637                 return -ERANGE;
 638
 639         fl = fl_create(net, sk, freq, optval, optlen, &err);
 640         if (!fl)
 641                 return err;
 642
 643         sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 644
 645         if (freq->flr_label) {
 646                 err = -EEXIST;
 647                 rcu_read_lock();
 648                 for_each_sk_fl_rcu(np, sfl) {
 649                         if (sfl->fl->label == freq->flr_label) {
 650                                 if (freq->flr_flags & IPV6_FL_F_EXCL) {
 651                                         rcu_read_unlock();
 652                                         goto done;
 653                                 }
 654                                 fl1 = sfl->fl;
 655                                 if (!atomic_inc_not_zero(&fl1->users))
 656                                         fl1 = NULL;
 657                                 break;
 658                         }
 659                 }
 660                 rcu_read_unlock();
 661
 662                 if (!fl1)
 663                         fl1 = fl_lookup(net, freq->flr_label);
 664                 if (fl1) {
 665 recheck:
 666                         err = -EEXIST;
 667                         if (freq->flr_flags&IPV6_FL_F_EXCL)
 668                                 goto release;
 669                         err = -EPERM;
 670                         if (fl1->share == IPV6_FL_S_EXCL ||
 671                             fl1->share != fl->share ||
 672                             ((fl1->share == IPV6_FL_S_PROCESS) &&
 673                              (fl1->owner.pid != fl->owner.pid)) ||
 674                             ((fl1->share == IPV6_FL_S_USER) &&
 675                              !uid_eq(fl1->owner.uid, fl->owner.uid)))
 676                                 goto release;
 677
 678                         err = -ENOMEM;
 679                         if (!sfl1)
 680                                 goto release;
 681                         if (fl->linger > fl1->linger)
 682                                 fl1->linger = fl->linger;
 683                         if ((long)(fl->expires - fl1->expires) > 0)
 684                                 fl1->expires = fl->expires;
 685                         fl_link(np, sfl1, fl1);
 686                         fl_free(fl);
 687                         return 0;
 688
 689 release:
 690                         fl_release(fl1);
 691                         goto done;
 692                 }
 693         }
 694         err = -ENOENT;
 695         if (!(freq->flr_flags & IPV6_FL_F_CREATE))
 696                 goto done;
 697
 698         err = -ENOMEM;
 699         if (!sfl1)
 700                 goto done;
 701
 702         err = mem_check(sk);
 703         if (err != 0)
 704                 goto done;
 705
 706         fl1 = fl_intern(net, fl, freq->flr_label);
 707         if (fl1)
 708                 goto recheck;
 709
 710         if (!freq->flr_label) {
 711                 size_t offset = offsetof(struct in6_flowlabel_req, flr_label);
 712
 713                 if (copy_to_sockptr_offset(optval, offset, &fl->label,
 714                                 sizeof(fl->label))) {
 715                         /* Intentionally ignore fault. */
 716                 }
 717         }
 718
 719         fl_link(np, sfl1, fl);
 720         return 0;
 721 done:
 722         fl_free(fl);
 723         kfree(sfl1);
 724         return err;
 725 }
 726
 727 int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)
 728 {
 729         struct in6_flowlabel_req freq;
 730
 731         if (optlen < sizeof(freq))
 732                 return -EINVAL;
 733         if (copy_from_sockptr(&freq, optval, sizeof(freq)))
 734                 return -EFAULT;
 735
 736         switch (freq.flr_action) {
 737         case IPV6_FL_A_PUT:
 738                 return ipv6_flowlabel_put(sk, &freq);
 739         case IPV6_FL_A_RENEW:
 740                 return ipv6_flowlabel_renew(sk, &freq);
 741         case IPV6_FL_A_GET:
 742                 return ipv6_flowlabel_get(sk, &freq, optval, optlen);
 743         default:
 744                 return -EINVAL;
 745         }
 746 }
 747
 748 #ifdef CONFIG_PROC_FS
 749
 750 struct ip6fl_iter_state {
 751         struct seq_net_private p;
 752         struct pid_namespace *pid_ns;
 753         int bucket;
 754 };
 755
 756 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 757
 758 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 759 {
 760         struct ip6_flowlabel *fl = NULL;
 761         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 762         struct net *net = seq_file_net(seq);
 763
 764         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 765                 for_each_fl_rcu(state->bucket, fl) {
 766                         if (net_eq(fl->fl_net, net))
 767                                 goto out;
 768                 }
 769         }
 770         fl = NULL;
 771 out:
 772         return fl;
 773 }
 774
 775 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 776 {
 777         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 778         struct net *net = seq_file_net(seq);
 779
 780         for_each_fl_continue_rcu(fl) {
 781                 if (net_eq(fl->fl_net, net))
 782                         goto out;
 783         }
 784
 785 try_again:
 786         if (++state->bucket <= FL_HASH_MASK) {
 787                 for_each_fl_rcu(state->bucket, fl) {
 788                         if (net_eq(fl->fl_net, net))
 789                                 goto out;
 790                 }
 791                 goto try_again;
 792         }
 793         fl = NULL;
 794
 795 out:
 796         return fl;
 797 }
 798
 799 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 800 {
 801         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 802         if (fl)
 803                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 804                         --pos;
 805         return pos ? NULL : fl;
 806 }
 807
 808 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 809         __acquires(RCU)
 810 {
 811         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 812
 813         state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
 814
 815         rcu_read_lock();
 816         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 817 }
 818
 819 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 820 {
 821         struct ip6_flowlabel *fl;
 822
 823         if (v == SEQ_START_TOKEN)
 824                 fl = ip6fl_get_first(seq);
 825         else
 826                 fl = ip6fl_get_next(seq, v);
 827         ++*pos;
 828         return fl;
 829 }
 830
 831 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 832         __releases(RCU)
 833 {
 834         rcu_read_unlock();
 835 }
 836
 837 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 838 {
 839         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 840         if (v == SEQ_START_TOKEN) {
 841                 seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
 842         } else {
 843                 struct ip6_flowlabel *fl = v;
 844                 seq_printf(seq,
 845                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 846                            (unsigned int)ntohl(fl->label),
 847                            fl->share,
 848                            ((fl->share == IPV6_FL_S_PROCESS) ?
 849                             pid_nr_ns(fl->owner.pid, state->pid_ns) :
 850                             ((fl->share == IPV6_FL_S_USER) ?
 851                              from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 852                              0)),
 853                            atomic_read(&fl->users),
 854                            fl->linger/HZ,
 855                            (long)(fl->expires - jiffies)/HZ,
 856                            &fl->dst,
 857                            fl->opt ? fl->opt->opt_nflen : 0);
 858         }
 859         return 0;
 860 }
 861
 862 static const struct seq_operations ip6fl_seq_ops = {
 863         .start  =       ip6fl_seq_start,
 864         .next   =       ip6fl_seq_next,
 865         .stop   =       ip6fl_seq_stop,
 866         .show   =       ip6fl_seq_show,
 867 };
 868
 869 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 870 {
 871         if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
 872                         &ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))
 873                 return -ENOMEM;
 874         return 0;
 875 }
 876
 877 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 878 {
 879         remove_proc_entry("ip6_flowlabel", net->proc_net);
 880 }
 881 #else
 882 static inline int ip6_flowlabel_proc_init(struct net *net)
 883 {
 884         return 0;
 885 }
 886 static inline void ip6_flowlabel_proc_fini(struct net *net)
 887 {
 888 }
 889 #endif
 890
 891 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 892 {
 893         ip6_fl_purge(net);
 894         ip6_flowlabel_proc_fini(net);
 895 }
 896
 897 static struct pernet_operations ip6_flowlabel_net_ops = {
 898         .init = ip6_flowlabel_proc_init,
 899         .exit = ip6_flowlabel_net_exit,
 900 };
 901
 902 int ip6_flowlabel_init(void)
 903 {
 904         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 905 }
 906
 907 void ip6_flowlabel_cleanup(void)
 908 {
 909         static_key_deferred_flush(&ipv6_flowlabel_exclusive);
 910         del_timer(&ip6_fl_gc_timer);
 911         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 912 }