net/ipv6/ip6_flowlabel.c

   1 /*
   2  *      ip6_flowlabel.c         IPv6 flowlabel manager.
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  *
   9  *      Authors:        Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 #include <linux/capability.h>
  13 #include <linux/errno.h>
  14 #include <linux/types.h>
  15 #include <linux/socket.h>
  16 #include <linux/net.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/in6.h>
  20 #include <linux/route.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/slab.h>
  24 #include <linux/export.h>
  25 #include <linux/pid_namespace.h>
  26
  27 #include <net/net_namespace.h>
  28 #include <net/sock.h>
  29
  30 #include <net/ipv6.h>
  31 #include <net/ndisc.h>
  32 #include <net/protocol.h>
  33 #include <net/ip6_route.h>
  34 #include <net/addrconf.h>
  35 #include <net/rawv6.h>
  36 #include <net/icmp.h>
  37 #include <net/transp_v6.h>
  38
  39 #include <asm/uaccess.h>
  40
  41 #define FL_MIN_LINGER   6       /* Minimal linger. It is set to 6sec specified
  42                                    in old IPv6 RFC. Well, it was reasonable value.
  43                                  */
  44 #define FL_MAX_LINGER   60      /* Maximal linger timeout */
  45
  46 /* FL hash table */
  47
  48 #define FL_MAX_PER_SOCK 32
  49 #define FL_MAX_SIZE     4096
  50 #define FL_HASH_MASK    255
  51 #define FL_HASH(l)      (ntohl(l)&FL_HASH_MASK)
  52
  53 static atomic_t fl_size = ATOMIC_INIT(0);
  54 static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
  55
  56 static void ip6_fl_gc(unsigned long dummy);
  57 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
  58
  59 /* FL hash table lock: it protects only of GC */
  60
  61 static DEFINE_SPINLOCK(ip6_fl_lock);
  62
  63 /* Big socket sock */
  64
  65 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
  66
  67 #define for_each_fl_rcu(hash, fl)                               \
  68         for (fl = rcu_dereference_bh(fl_ht[(hash)]);            \
  69              fl != NULL;                                        \
  70              fl = rcu_dereference_bh(fl->next))
  71 #define for_each_fl_continue_rcu(fl)                            \
  72         for (fl = rcu_dereference_bh(fl->next);                 \
  73              fl != NULL;                                        \
  74              fl = rcu_dereference_bh(fl->next))
  75
  76 #define for_each_sk_fl_rcu(np, sfl)                             \
  77         for (sfl = rcu_dereference_bh(np->ipv6_fl_list);        \
  78              sfl != NULL;                                       \
  79              sfl = rcu_dereference_bh(sfl->next))
  80
  81 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
  82 {
  83         struct ip6_flowlabel *fl;
  84
  85         for_each_fl_rcu(FL_HASH(label), fl) {
  86                 if (fl->label == label && net_eq(fl->fl_net, net))
  87                         return fl;
  88         }
  89         return NULL;
  90 }
  91
  92 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
  93 {
  94         struct ip6_flowlabel *fl;
  95
  96         rcu_read_lock_bh();
  97         fl = __fl_lookup(net, label);
  98         if (fl && !atomic_inc_not_zero(&fl->users))
  99                 fl = NULL;
 100         rcu_read_unlock_bh();
 101         return fl;
 102 }
 103
 104
 105 static void fl_free(struct ip6_flowlabel *fl)
 106 {
 107         if (fl) {
 108                 if (fl->share == IPV6_FL_S_PROCESS)
 109                         put_pid(fl->owner.pid);
 110                 release_net(fl->fl_net);
 111                 kfree(fl->opt);
 112                 kfree_rcu(fl, rcu);
 113         }
 114 }
 115
 116 static void fl_release(struct ip6_flowlabel *fl)
 117 {
 118         spin_lock_bh(&ip6_fl_lock);
 119
 120         fl->lastuse = jiffies;
 121         if (atomic_dec_and_test(&fl->users)) {
 122                 unsigned long ttd = fl->lastuse + fl->linger;
 123                 if (time_after(ttd, fl->expires))
 124                         fl->expires = ttd;
 125                 ttd = fl->expires;
 126                 if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
 127                         struct ipv6_txoptions *opt = fl->opt;
 128                         fl->opt = NULL;
 129                         kfree(opt);
 130                 }
 131                 if (!timer_pending(&ip6_fl_gc_timer) ||
 132                     time_after(ip6_fl_gc_timer.expires, ttd))
 133                         mod_timer(&ip6_fl_gc_timer, ttd);
 134         }
 135         spin_unlock_bh(&ip6_fl_lock);
 136 }
 137
 138 static void ip6_fl_gc(unsigned long dummy)
 139 {
 140         int i;
 141         unsigned long now = jiffies;
 142         unsigned long sched = 0;
 143
 144         spin_lock(&ip6_fl_lock);
 145
 146         for (i=0; i<=FL_HASH_MASK; i++) {
 147                 struct ip6_flowlabel *fl;
 148                 struct ip6_flowlabel __rcu **flp;
 149
 150                 flp = &fl_ht[i];
 151                 while ((fl = rcu_dereference_protected(*flp,
 152                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 153                         if (atomic_read(&fl->users) == 0) {
 154                                 unsigned long ttd = fl->lastuse + fl->linger;
 155                                 if (time_after(ttd, fl->expires))
 156                                         fl->expires = ttd;
 157                                 ttd = fl->expires;
 158                                 if (time_after_eq(now, ttd)) {
 159                                         *flp = fl->next;
 160                                         fl_free(fl);
 161                                         atomic_dec(&fl_size);
 162                                         continue;
 163                                 }
 164                                 if (!sched || time_before(ttd, sched))
 165                                         sched = ttd;
 166                         }
 167                         flp = &fl->next;
 168                 }
 169         }
 170         if (!sched && atomic_read(&fl_size))
 171                 sched = now + FL_MAX_LINGER;
 172         if (sched) {
 173                 mod_timer(&ip6_fl_gc_timer, sched);
 174         }
 175         spin_unlock(&ip6_fl_lock);
 176 }
 177
 178 static void __net_exit ip6_fl_purge(struct net *net)
 179 {
 180         int i;
 181
 182         spin_lock(&ip6_fl_lock);
 183         for (i = 0; i <= FL_HASH_MASK; i++) {
 184                 struct ip6_flowlabel *fl;
 185                 struct ip6_flowlabel __rcu **flp;
 186
 187                 flp = &fl_ht[i];
 188                 while ((fl = rcu_dereference_protected(*flp,
 189                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 190                         if (net_eq(fl->fl_net, net) &&
 191                             atomic_read(&fl->users) == 0) {
 192                                 *flp = fl->next;
 193                                 fl_free(fl);
 194                                 atomic_dec(&fl_size);
 195                                 continue;
 196                         }
 197                         flp = &fl->next;
 198                 }
 199         }
 200         spin_unlock(&ip6_fl_lock);
 201 }
 202
 203 static struct ip6_flowlabel *fl_intern(struct net *net,
 204                                        struct ip6_flowlabel *fl, __be32 label)
 205 {
 206         struct ip6_flowlabel *lfl;
 207
 208         fl->label = label & IPV6_FLOWLABEL_MASK;
 209
 210         spin_lock_bh(&ip6_fl_lock);
 211         if (label == 0) {
 212                 for (;;) {
 213                         fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
 214                         if (fl->label) {
 215                                 lfl = __fl_lookup(net, fl->label);
 216                                 if (lfl == NULL)
 217                                         break;
 218                         }
 219                 }
 220         } else {
 221                 /*
 222                  * we dropper the ip6_fl_lock, so this entry could reappear
 223                  * and we need to recheck with it.
 224                  *
 225                  * OTOH no need to search the active socket first, like it is
 226                  * done in ipv6_flowlabel_opt - sock is locked, so new entry
 227                  * with the same label can only appear on another sock
 228                  */
 229                 lfl = __fl_lookup(net, fl->label);
 230                 if (lfl != NULL) {
 231                         atomic_inc(&lfl->users);
 232                         spin_unlock_bh(&ip6_fl_lock);
 233                         return lfl;
 234                 }
 235         }
 236
 237         fl->lastuse = jiffies;
 238         fl->next = fl_ht[FL_HASH(fl->label)];
 239         rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
 240         atomic_inc(&fl_size);
 241         spin_unlock_bh(&ip6_fl_lock);
 242         return NULL;
 243 }
 244
 245
 246
 247 /* Socket flowlabel lists */
 248
 249 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
 250 {
 251         struct ipv6_fl_socklist *sfl;
 252         struct ipv6_pinfo *np = inet6_sk(sk);
 253
 254         label &= IPV6_FLOWLABEL_MASK;
 255
 256         rcu_read_lock_bh();
 257         for_each_sk_fl_rcu(np, sfl) {
 258                 struct ip6_flowlabel *fl = sfl->fl;
 259                 if (fl->label == label) {
 260                         fl->lastuse = jiffies;
 261                         atomic_inc(&fl->users);
 262                         rcu_read_unlock_bh();
 263                         return fl;
 264                 }
 265         }
 266         rcu_read_unlock_bh();
 267         return NULL;
 268 }
 269
 270 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
 271
 272 void fl6_free_socklist(struct sock *sk)
 273 {
 274         struct ipv6_pinfo *np = inet6_sk(sk);
 275         struct ipv6_fl_socklist *sfl;
 276
 277         if (!rcu_access_pointer(np->ipv6_fl_list))
 278                 return;
 279
 280         spin_lock_bh(&ip6_sk_fl_lock);
 281         while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
 282                                                 lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
 283                 np->ipv6_fl_list = sfl->next;
 284                 spin_unlock_bh(&ip6_sk_fl_lock);
 285
 286                 fl_release(sfl->fl);
 287                 kfree_rcu(sfl, rcu);
 288
 289                 spin_lock_bh(&ip6_sk_fl_lock);
 290         }
 291         spin_unlock_bh(&ip6_sk_fl_lock);
 292 }
 293
 294 /* Service routines */
 295
 296
 297 /*
 298    It is the only difficult place. flowlabel enforces equal headers
 299    before and including routing header, however user may supply options
 300    following rthdr.
 301  */
 302
 303 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
 304                                          struct ip6_flowlabel * fl,
 305                                          struct ipv6_txoptions * fopt)
 306 {
 307         struct ipv6_txoptions * fl_opt = fl->opt;
 308
 309         if (fopt == NULL || fopt->opt_flen == 0)
 310                 return fl_opt;
 311
 312         if (fl_opt != NULL) {
 313                 opt_space->hopopt = fl_opt->hopopt;
 314                 opt_space->dst0opt = fl_opt->dst0opt;
 315                 opt_space->srcrt = fl_opt->srcrt;
 316                 opt_space->opt_nflen = fl_opt->opt_nflen;
 317         } else {
 318                 if (fopt->opt_nflen == 0)
 319                         return fopt;
 320                 opt_space->hopopt = NULL;
 321                 opt_space->dst0opt = NULL;
 322                 opt_space->srcrt = NULL;
 323                 opt_space->opt_nflen = 0;
 324         }
 325         opt_space->dst1opt = fopt->dst1opt;
 326         opt_space->opt_flen = fopt->opt_flen;
 327         return opt_space;
 328 }
 329 EXPORT_SYMBOL_GPL(fl6_merge_options);
 330
 331 static unsigned long check_linger(unsigned long ttl)
 332 {
 333         if (ttl < FL_MIN_LINGER)
 334                 return FL_MIN_LINGER*HZ;
 335         if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
 336                 return 0;
 337         return ttl*HZ;
 338 }
 339
 340 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
 341 {
 342         linger = check_linger(linger);
 343         if (!linger)
 344                 return -EPERM;
 345         expires = check_linger(expires);
 346         if (!expires)
 347                 return -EPERM;
 348         fl->lastuse = jiffies;
 349         if (time_before(fl->linger, linger))
 350                 fl->linger = linger;
 351         if (time_before(expires, fl->linger))
 352                 expires = fl->linger;
 353         if (time_before(fl->expires, fl->lastuse + expires))
 354                 fl->expires = fl->lastuse + expires;
 355         return 0;
 356 }
 357
 358 static struct ip6_flowlabel *
 359 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 360           char __user *optval, int optlen, int *err_p)
 361 {
 362         struct ip6_flowlabel *fl = NULL;
 363         int olen;
 364         int addr_type;
 365         int err;
 366
 367         olen = optlen - CMSG_ALIGN(sizeof(*freq));
 368         err = -EINVAL;
 369         if (olen > 64 * 1024)
 370                 goto done;
 371
 372         err = -ENOMEM;
 373         fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 374         if (fl == NULL)
 375                 goto done;
 376
 377         if (olen > 0) {
 378                 struct msghdr msg;
 379                 struct flowi6 flowi6;
 380                 int junk;
 381
 382                 err = -ENOMEM;
 383                 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 384                 if (fl->opt == NULL)
 385                         goto done;
 386
 387                 memset(fl->opt, 0, sizeof(*fl->opt));
 388                 fl->opt->tot_len = sizeof(*fl->opt) + olen;
 389                 err = -EFAULT;
 390                 if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
 391                         goto done;
 392
 393                 msg.msg_controllen = olen;
 394                 msg.msg_control = (void*)(fl->opt+1);
 395                 memset(&flowi6, 0, sizeof(flowi6));
 396
 397                 err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt,
 398                                             &junk, &junk, &junk);
 399                 if (err)
 400                         goto done;
 401                 err = -EINVAL;
 402                 if (fl->opt->opt_flen)
 403                         goto done;
 404                 if (fl->opt->opt_nflen == 0) {
 405                         kfree(fl->opt);
 406                         fl->opt = NULL;
 407                 }
 408         }
 409
 410         fl->fl_net = hold_net(net);
 411         fl->expires = jiffies;
 412         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 413         if (err)
 414                 goto done;
 415         fl->share = freq->flr_share;
 416         addr_type = ipv6_addr_type(&freq->flr_dst);
 417         if ((addr_type & IPV6_ADDR_MAPPED) ||
 418             addr_type == IPV6_ADDR_ANY) {
 419                 err = -EINVAL;
 420                 goto done;
 421         }
 422         fl->dst = freq->flr_dst;
 423         atomic_set(&fl->users, 1);
 424         switch (fl->share) {
 425         case IPV6_FL_S_EXCL:
 426         case IPV6_FL_S_ANY:
 427                 break;
 428         case IPV6_FL_S_PROCESS:
 429                 fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 430                 break;
 431         case IPV6_FL_S_USER:
 432                 fl->owner.uid = current_euid();
 433                 break;
 434         default:
 435                 err = -EINVAL;
 436                 goto done;
 437         }
 438         return fl;
 439
 440 done:
 441         fl_free(fl);
 442         *err_p = err;
 443         return NULL;
 444 }
 445
 446 static int mem_check(struct sock *sk)
 447 {
 448         struct ipv6_pinfo *np = inet6_sk(sk);
 449         struct ipv6_fl_socklist *sfl;
 450         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 451         int count = 0;
 452
 453         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 454                 return 0;
 455
 456         for_each_sk_fl_rcu(np, sfl)
 457                 count++;
 458
 459         if (room <= 0 ||
 460             ((count >= FL_MAX_PER_SOCK ||
 461               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 462              !capable(CAP_NET_ADMIN)))
 463                 return -ENOBUFS;
 464
 465         return 0;
 466 }
 467
 468 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 469                 struct ip6_flowlabel *fl)
 470 {
 471         spin_lock_bh(&ip6_sk_fl_lock);
 472         sfl->fl = fl;
 473         sfl->next = np->ipv6_fl_list;
 474         rcu_assign_pointer(np->ipv6_fl_list, sfl);
 475         spin_unlock_bh(&ip6_sk_fl_lock);
 476 }
 477
 478 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 479 {
 480         int uninitialized_var(err);
 481         struct net *net = sock_net(sk);
 482         struct ipv6_pinfo *np = inet6_sk(sk);
 483         struct in6_flowlabel_req freq;
 484         struct ipv6_fl_socklist *sfl1=NULL;
 485         struct ipv6_fl_socklist *sfl;
 486         struct ipv6_fl_socklist __rcu **sflp;
 487         struct ip6_flowlabel *fl, *fl1 = NULL;
 488
 489
 490         if (optlen < sizeof(freq))
 491                 return -EINVAL;
 492
 493         if (copy_from_user(&freq, optval, sizeof(freq)))
 494                 return -EFAULT;
 495
 496         switch (freq.flr_action) {
 497         case IPV6_FL_A_PUT:
 498                 spin_lock_bh(&ip6_sk_fl_lock);
 499                 for (sflp = &np->ipv6_fl_list;
 500                      (sfl = rcu_dereference(*sflp))!=NULL;
 501                      sflp = &sfl->next) {
 502                         if (sfl->fl->label == freq.flr_label) {
 503                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 504                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 505                                 *sflp = rcu_dereference(sfl->next);
 506                                 spin_unlock_bh(&ip6_sk_fl_lock);
 507                                 fl_release(sfl->fl);
 508                                 kfree_rcu(sfl, rcu);
 509                                 return 0;
 510                         }
 511                 }
 512                 spin_unlock_bh(&ip6_sk_fl_lock);
 513                 return -ESRCH;
 514
 515         case IPV6_FL_A_RENEW:
 516                 rcu_read_lock_bh();
 517                 for_each_sk_fl_rcu(np, sfl) {
 518                         if (sfl->fl->label == freq.flr_label) {
 519                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 520                                 rcu_read_unlock_bh();
 521                                 return err;
 522                         }
 523                 }
 524                 rcu_read_unlock_bh();
 525
 526                 if (freq.flr_share == IPV6_FL_S_NONE &&
 527                     ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 528                         fl = fl_lookup(net, freq.flr_label);
 529                         if (fl) {
 530                                 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 531                                 fl_release(fl);
 532                                 return err;
 533                         }
 534                 }
 535                 return -ESRCH;
 536
 537         case IPV6_FL_A_GET:
 538                 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 539                         return -EINVAL;
 540
 541                 fl = fl_create(net, sk, &freq, optval, optlen, &err);
 542                 if (fl == NULL)
 543                         return err;
 544                 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 545
 546                 if (freq.flr_label) {
 547                         err = -EEXIST;
 548                         rcu_read_lock_bh();
 549                         for_each_sk_fl_rcu(np, sfl) {
 550                                 if (sfl->fl->label == freq.flr_label) {
 551                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
 552                                                 rcu_read_unlock_bh();
 553                                                 goto done;
 554                                         }
 555                                         fl1 = sfl->fl;
 556                                         atomic_inc(&fl1->users);
 557                                         break;
 558                                 }
 559                         }
 560                         rcu_read_unlock_bh();
 561
 562                         if (fl1 == NULL)
 563                                 fl1 = fl_lookup(net, freq.flr_label);
 564                         if (fl1) {
 565 recheck:
 566                                 err = -EEXIST;
 567                                 if (freq.flr_flags&IPV6_FL_F_EXCL)
 568                                         goto release;
 569                                 err = -EPERM;
 570                                 if (fl1->share == IPV6_FL_S_EXCL ||
 571                                     fl1->share != fl->share ||
 572                                     ((fl1->share == IPV6_FL_S_PROCESS) &&
 573                                      (fl1->owner.pid == fl->owner.pid)) ||
 574                                     ((fl1->share == IPV6_FL_S_USER) &&
 575                                      uid_eq(fl1->owner.uid, fl->owner.uid)))
 576                                         goto release;
 577
 578                                 err = -ENOMEM;
 579                                 if (sfl1 == NULL)
 580                                         goto release;
 581                                 if (fl->linger > fl1->linger)
 582                                         fl1->linger = fl->linger;
 583                                 if ((long)(fl->expires - fl1->expires) > 0)
 584                                         fl1->expires = fl->expires;
 585                                 fl_link(np, sfl1, fl1);
 586                                 fl_free(fl);
 587                                 return 0;
 588
 589 release:
 590                                 fl_release(fl1);
 591                                 goto done;
 592                         }
 593                 }
 594                 err = -ENOENT;
 595                 if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 596                         goto done;
 597
 598                 err = -ENOMEM;
 599                 if (sfl1 == NULL || (err = mem_check(sk)) != 0)
 600                         goto done;
 601
 602                 fl1 = fl_intern(net, fl, freq.flr_label);
 603                 if (fl1 != NULL)
 604                         goto recheck;
 605
 606                 if (!freq.flr_label) {
 607                         if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 608                                          &fl->label, sizeof(fl->label))) {
 609                                 /* Intentionally ignore fault. */
 610                         }
 611                 }
 612
 613                 fl_link(np, sfl1, fl);
 614                 return 0;
 615
 616         default:
 617                 return -EINVAL;
 618         }
 619
 620 done:
 621         fl_free(fl);
 622         kfree(sfl1);
 623         return err;
 624 }
 625
 626 #ifdef CONFIG_PROC_FS
 627
 628 struct ip6fl_iter_state {
 629         struct seq_net_private p;
 630         struct pid_namespace *pid_ns;
 631         int bucket;
 632 };
 633
 634 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 635
 636 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 637 {
 638         struct ip6_flowlabel *fl = NULL;
 639         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 640         struct net *net = seq_file_net(seq);
 641
 642         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 643                 for_each_fl_rcu(state->bucket, fl) {
 644                         if (net_eq(fl->fl_net, net))
 645                                 goto out;
 646                 }
 647         }
 648         fl = NULL;
 649 out:
 650         return fl;
 651 }
 652
 653 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 654 {
 655         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 656         struct net *net = seq_file_net(seq);
 657
 658         for_each_fl_continue_rcu(fl) {
 659                 if (net_eq(fl->fl_net, net))
 660                         goto out;
 661         }
 662
 663 try_again:
 664         if (++state->bucket <= FL_HASH_MASK) {
 665                 for_each_fl_rcu(state->bucket, fl) {
 666                         if (net_eq(fl->fl_net, net))
 667                                 goto out;
 668                 }
 669                 goto try_again;
 670         }
 671         fl = NULL;
 672
 673 out:
 674         return fl;
 675 }
 676
 677 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 678 {
 679         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 680         if (fl)
 681                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 682                         --pos;
 683         return pos ? NULL : fl;
 684 }
 685
 686 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 687         __acquires(RCU)
 688 {
 689         rcu_read_lock_bh();
 690         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 691 }
 692
 693 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 694 {
 695         struct ip6_flowlabel *fl;
 696
 697         if (v == SEQ_START_TOKEN)
 698                 fl = ip6fl_get_first(seq);
 699         else
 700                 fl = ip6fl_get_next(seq, v);
 701         ++*pos;
 702         return fl;
 703 }
 704
 705 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 706         __releases(RCU)
 707 {
 708         rcu_read_unlock_bh();
 709 }
 710
 711 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 712 {
 713         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 714         if (v == SEQ_START_TOKEN)
 715                 seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
 716                            "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
 717         else {
 718                 struct ip6_flowlabel *fl = v;
 719                 seq_printf(seq,
 720                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 721                            (unsigned int)ntohl(fl->label),
 722                            fl->share,
 723                            ((fl->share == IPV6_FL_S_PROCESS) ?
 724                             pid_nr_ns(fl->owner.pid, state->pid_ns) :
 725                             ((fl->share == IPV6_FL_S_USER) ?
 726                              from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 727                              0)),
 728                            atomic_read(&fl->users),
 729                            fl->linger/HZ,
 730                            (long)(fl->expires - jiffies)/HZ,
 731                            &fl->dst,
 732                            fl->opt ? fl->opt->opt_nflen : 0);
 733         }
 734         return 0;
 735 }
 736
 737 static const struct seq_operations ip6fl_seq_ops = {
 738         .start  =       ip6fl_seq_start,
 739         .next   =       ip6fl_seq_next,
 740         .stop   =       ip6fl_seq_stop,
 741         .show   =       ip6fl_seq_show,
 742 };
 743
 744 static int ip6fl_seq_open(struct inode *inode, struct file *file)
 745 {
 746         struct seq_file *seq;
 747         struct ip6fl_iter_state *state;
 748         int err;
 749
 750         err = seq_open_net(inode, file, &ip6fl_seq_ops,
 751                            sizeof(struct ip6fl_iter_state));
 752
 753         if (!err) {
 754                 seq = file->private_data;
 755                 state = ip6fl_seq_private(seq);
 756                 rcu_read_lock();
 757                 state->pid_ns = get_pid_ns(task_active_pid_ns(current));
 758                 rcu_read_unlock();
 759         }
 760         return err;
 761 }
 762
 763 static int ip6fl_seq_release(struct inode *inode, struct file *file)
 764 {
 765         struct seq_file *seq = file->private_data;
 766         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 767         put_pid_ns(state->pid_ns);
 768         return seq_release_net(inode, file);
 769 }
 770
 771 static const struct file_operations ip6fl_seq_fops = {
 772         .owner          =       THIS_MODULE,
 773         .open           =       ip6fl_seq_open,
 774         .read           =       seq_read,
 775         .llseek         =       seq_lseek,
 776         .release        =       ip6fl_seq_release,
 777 };
 778
 779 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 780 {
 781         if (!proc_create("ip6_flowlabel", S_IRUGO, net->proc_net,
 782                          &ip6fl_seq_fops))
 783                 return -ENOMEM;
 784         return 0;
 785 }
 786
 787 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 788 {
 789         remove_proc_entry("ip6_flowlabel", net->proc_net);
 790 }
 791 #else
 792 static inline int ip6_flowlabel_proc_init(struct net *net)
 793 {
 794         return 0;
 795 }
 796 static inline void ip6_flowlabel_proc_fini(struct net *net)
 797 {
 798 }
 799 #endif
 800
 801 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 802 {
 803         ip6_fl_purge(net);
 804         ip6_flowlabel_proc_fini(net);
 805 }
 806
 807 static struct pernet_operations ip6_flowlabel_net_ops = {
 808         .init = ip6_flowlabel_proc_init,
 809         .exit = ip6_flowlabel_net_exit,
 810 };
 811
 812 int ip6_flowlabel_init(void)
 813 {
 814         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 815 }
 816
 817 void ip6_flowlabel_cleanup(void)
 818 {
 819         del_timer(&ip6_fl_gc_timer);
 820         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 821 }