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
  25 #include <net/net_namespace.h>
  26 #include <net/sock.h>
  27
  28 #include <net/ipv6.h>
  29 #include <net/ndisc.h>
  30 #include <net/protocol.h>
  31 #include <net/ip6_route.h>
  32 #include <net/addrconf.h>
  33 #include <net/rawv6.h>
  34 #include <net/icmp.h>
  35 #include <net/transp_v6.h>
  36
  37 #include <asm/uaccess.h>
  38
  39 #define FL_MIN_LINGER   6       /* Minimal linger. It is set to 6sec specified
  40                                    in old IPv6 RFC. Well, it was reasonable value.
  41                                  */
  42 #define FL_MAX_LINGER   60      /* Maximal linger timeout */
  43
  44 /* FL hash table */
  45
  46 #define FL_MAX_PER_SOCK 32
  47 #define FL_MAX_SIZE     4096
  48 #define FL_HASH_MASK    255
  49 #define FL_HASH(l)      (ntohl(l)&FL_HASH_MASK)
  50
  51 static atomic_t fl_size = ATOMIC_INIT(0);
  52 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
  53
  54 static void ip6_fl_gc(unsigned long dummy);
  55 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
  56
  57 /* FL hash table lock: it protects only of GC */
  58
  59 static DEFINE_RWLOCK(ip6_fl_lock);
  60
  61 /* Big socket sock */
  62
  63 static DEFINE_RWLOCK(ip6_sk_fl_lock);
  64
  65
  66 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
  67 {
  68         struct ip6_flowlabel *fl;
  69
  70         for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) {
  71                 if (fl->label == label && net_eq(fl->fl_net, net))
  72                         return fl;
  73         }
  74         return NULL;
  75 }
  76
  77 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
  78 {
  79         struct ip6_flowlabel *fl;
  80
  81         read_lock_bh(&ip6_fl_lock);
  82         fl = __fl_lookup(net, label);
  83         if (fl)
  84                 atomic_inc(&fl->users);
  85         read_unlock_bh(&ip6_fl_lock);
  86         return fl;
  87 }
  88
  89
  90 static void fl_free(struct ip6_flowlabel *fl)
  91 {
  92         if (fl) {
  93                 release_net(fl->fl_net);
  94                 kfree(fl->opt);
  95         }
  96         kfree(fl);
  97 }
  98
  99 static void fl_release(struct ip6_flowlabel *fl)
 100 {
 101         write_lock_bh(&ip6_fl_lock);
 102
 103         fl->lastuse = jiffies;
 104         if (atomic_dec_and_test(&fl->users)) {
 105                 unsigned long ttd = fl->lastuse + fl->linger;
 106                 if (time_after(ttd, fl->expires))
 107                         fl->expires = ttd;
 108                 ttd = fl->expires;
 109                 if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
 110                         struct ipv6_txoptions *opt = fl->opt;
 111                         fl->opt = NULL;
 112                         kfree(opt);
 113                 }
 114                 if (!timer_pending(&ip6_fl_gc_timer) ||
 115                     time_after(ip6_fl_gc_timer.expires, ttd))
 116                         mod_timer(&ip6_fl_gc_timer, ttd);
 117         }
 118         write_unlock_bh(&ip6_fl_lock);
 119 }
 120
 121 static void ip6_fl_gc(unsigned long dummy)
 122 {
 123         int i;
 124         unsigned long now = jiffies;
 125         unsigned long sched = 0;
 126
 127         write_lock(&ip6_fl_lock);
 128
 129         for (i=0; i<=FL_HASH_MASK; i++) {
 130                 struct ip6_flowlabel *fl, **flp;
 131                 flp = &fl_ht[i];
 132                 while ((fl=*flp) != NULL) {
 133                         if (atomic_read(&fl->users) == 0) {
 134                                 unsigned long ttd = fl->lastuse + fl->linger;
 135                                 if (time_after(ttd, fl->expires))
 136                                         fl->expires = ttd;
 137                                 ttd = fl->expires;
 138                                 if (time_after_eq(now, ttd)) {
 139                                         *flp = fl->next;
 140                                         fl_free(fl);
 141                                         atomic_dec(&fl_size);
 142                                         continue;
 143                                 }
 144                                 if (!sched || time_before(ttd, sched))
 145                                         sched = ttd;
 146                         }
 147                         flp = &fl->next;
 148                 }
 149         }
 150         if (!sched && atomic_read(&fl_size))
 151                 sched = now + FL_MAX_LINGER;
 152         if (sched) {
 153                 mod_timer(&ip6_fl_gc_timer, sched);
 154         }
 155         write_unlock(&ip6_fl_lock);
 156 }
 157
 158 static void __net_exit ip6_fl_purge(struct net *net)
 159 {
 160         int i;
 161
 162         write_lock(&ip6_fl_lock);
 163         for (i = 0; i <= FL_HASH_MASK; i++) {
 164                 struct ip6_flowlabel *fl, **flp;
 165                 flp = &fl_ht[i];
 166                 while ((fl = *flp) != NULL) {
 167                         if (net_eq(fl->fl_net, net) &&
 168                             atomic_read(&fl->users) == 0) {
 169                                 *flp = fl->next;
 170                                 fl_free(fl);
 171                                 atomic_dec(&fl_size);
 172                                 continue;
 173                         }
 174                         flp = &fl->next;
 175                 }
 176         }
 177         write_unlock(&ip6_fl_lock);
 178 }
 179
 180 static struct ip6_flowlabel *fl_intern(struct net *net,
 181                                        struct ip6_flowlabel *fl, __be32 label)
 182 {
 183         struct ip6_flowlabel *lfl;
 184
 185         fl->label = label & IPV6_FLOWLABEL_MASK;
 186
 187         write_lock_bh(&ip6_fl_lock);
 188         if (label == 0) {
 189                 for (;;) {
 190                         fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK;
 191                         if (fl->label) {
 192                                 lfl = __fl_lookup(net, fl->label);
 193                                 if (lfl == NULL)
 194                                         break;
 195                         }
 196                 }
 197         } else {
 198                 /*
 199                  * we dropper the ip6_fl_lock, so this entry could reappear
 200                  * and we need to recheck with it.
 201                  *
 202                  * OTOH no need to search the active socket first, like it is
 203                  * done in ipv6_flowlabel_opt - sock is locked, so new entry
 204                  * with the same label can only appear on another sock
 205                  */
 206                 lfl = __fl_lookup(net, fl->label);
 207                 if (lfl != NULL) {
 208                         atomic_inc(&lfl->users);
 209                         write_unlock_bh(&ip6_fl_lock);
 210                         return lfl;
 211                 }
 212         }
 213
 214         fl->lastuse = jiffies;
 215         fl->next = fl_ht[FL_HASH(fl->label)];
 216         fl_ht[FL_HASH(fl->label)] = fl;
 217         atomic_inc(&fl_size);
 218         write_unlock_bh(&ip6_fl_lock);
 219         return NULL;
 220 }
 221
 222
 223
 224 /* Socket flowlabel lists */
 225
 226 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
 227 {
 228         struct ipv6_fl_socklist *sfl;
 229         struct ipv6_pinfo *np = inet6_sk(sk);
 230
 231         label &= IPV6_FLOWLABEL_MASK;
 232
 233         read_lock_bh(&ip6_sk_fl_lock);
 234         for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
 235                 struct ip6_flowlabel *fl = sfl->fl;
 236                 if (fl->label == label) {
 237                         fl->lastuse = jiffies;
 238                         atomic_inc(&fl->users);
 239                         read_unlock_bh(&ip6_sk_fl_lock);
 240                         return fl;
 241                 }
 242         }
 243         read_unlock_bh(&ip6_sk_fl_lock);
 244         return NULL;
 245 }
 246
 247 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
 248
 249 void fl6_free_socklist(struct sock *sk)
 250 {
 251         struct ipv6_pinfo *np = inet6_sk(sk);
 252         struct ipv6_fl_socklist *sfl;
 253
 254         while ((sfl = np->ipv6_fl_list) != NULL) {
 255                 np->ipv6_fl_list = sfl->next;
 256                 fl_release(sfl->fl);
 257                 kfree(sfl);
 258         }
 259 }
 260
 261 /* Service routines */
 262
 263
 264 /*
 265    It is the only difficult place. flowlabel enforces equal headers
 266    before and including routing header, however user may supply options
 267    following rthdr.
 268  */
 269
 270 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space,
 271                                          struct ip6_flowlabel * fl,
 272                                          struct ipv6_txoptions * fopt)
 273 {
 274         struct ipv6_txoptions * fl_opt = fl->opt;
 275
 276         if (fopt == NULL || fopt->opt_flen == 0)
 277                 return fl_opt;
 278
 279         if (fl_opt != NULL) {
 280                 opt_space->hopopt = fl_opt->hopopt;
 281                 opt_space->dst0opt = fl_opt->dst0opt;
 282                 opt_space->srcrt = fl_opt->srcrt;
 283                 opt_space->opt_nflen = fl_opt->opt_nflen;
 284         } else {
 285                 if (fopt->opt_nflen == 0)
 286                         return fopt;
 287                 opt_space->hopopt = NULL;
 288                 opt_space->dst0opt = NULL;
 289                 opt_space->srcrt = NULL;
 290                 opt_space->opt_nflen = 0;
 291         }
 292         opt_space->dst1opt = fopt->dst1opt;
 293         opt_space->opt_flen = fopt->opt_flen;
 294         return opt_space;
 295 }
 296
 297 static unsigned long check_linger(unsigned long ttl)
 298 {
 299         if (ttl < FL_MIN_LINGER)
 300                 return FL_MIN_LINGER*HZ;
 301         if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
 302                 return 0;
 303         return ttl*HZ;
 304 }
 305
 306 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
 307 {
 308         linger = check_linger(linger);
 309         if (!linger)
 310                 return -EPERM;
 311         expires = check_linger(expires);
 312         if (!expires)
 313                 return -EPERM;
 314         fl->lastuse = jiffies;
 315         if (time_before(fl->linger, linger))
 316                 fl->linger = linger;
 317         if (time_before(expires, fl->linger))
 318                 expires = fl->linger;
 319         if (time_before(fl->expires, fl->lastuse + expires))
 320                 fl->expires = fl->lastuse + expires;
 321         return 0;
 322 }
 323
 324 static struct ip6_flowlabel *
 325 fl_create(struct net *net, struct in6_flowlabel_req *freq, char __user *optval,
 326           int optlen, int *err_p)
 327 {
 328         struct ip6_flowlabel *fl = NULL;
 329         int olen;
 330         int addr_type;
 331         int err;
 332
 333         olen = optlen - CMSG_ALIGN(sizeof(*freq));
 334         err = -EINVAL;
 335         if (olen > 64 * 1024)
 336                 goto done;
 337
 338         err = -ENOMEM;
 339         fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 340         if (fl == NULL)
 341                 goto done;
 342
 343         if (olen > 0) {
 344                 struct msghdr msg;
 345                 struct flowi flowi;
 346                 int junk;
 347
 348                 err = -ENOMEM;
 349                 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 350                 if (fl->opt == NULL)
 351                         goto done;
 352
 353                 memset(fl->opt, 0, sizeof(*fl->opt));
 354                 fl->opt->tot_len = sizeof(*fl->opt) + olen;
 355                 err = -EFAULT;
 356                 if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
 357                         goto done;
 358
 359                 msg.msg_controllen = olen;
 360                 msg.msg_control = (void*)(fl->opt+1);
 361                 flowi.oif = 0;
 362
 363                 err = datagram_send_ctl(net, &msg, &flowi, fl->opt, &junk,
 364                                         &junk, &junk);
 365                 if (err)
 366                         goto done;
 367                 err = -EINVAL;
 368                 if (fl->opt->opt_flen)
 369                         goto done;
 370                 if (fl->opt->opt_nflen == 0) {
 371                         kfree(fl->opt);
 372                         fl->opt = NULL;
 373                 }
 374         }
 375
 376         fl->fl_net = hold_net(net);
 377         fl->expires = jiffies;
 378         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 379         if (err)
 380                 goto done;
 381         fl->share = freq->flr_share;
 382         addr_type = ipv6_addr_type(&freq->flr_dst);
 383         if ((addr_type & IPV6_ADDR_MAPPED) ||
 384             addr_type == IPV6_ADDR_ANY) {
 385                 err = -EINVAL;
 386                 goto done;
 387         }
 388         ipv6_addr_copy(&fl->dst, &freq->flr_dst);
 389         atomic_set(&fl->users, 1);
 390         switch (fl->share) {
 391         case IPV6_FL_S_EXCL:
 392         case IPV6_FL_S_ANY:
 393                 break;
 394         case IPV6_FL_S_PROCESS:
 395                 fl->owner = current->pid;
 396                 break;
 397         case IPV6_FL_S_USER:
 398                 fl->owner = current_euid();
 399                 break;
 400         default:
 401                 err = -EINVAL;
 402                 goto done;
 403         }
 404         return fl;
 405
 406 done:
 407         fl_free(fl);
 408         *err_p = err;
 409         return NULL;
 410 }
 411
 412 static int mem_check(struct sock *sk)
 413 {
 414         struct ipv6_pinfo *np = inet6_sk(sk);
 415         struct ipv6_fl_socklist *sfl;
 416         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 417         int count = 0;
 418
 419         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 420                 return 0;
 421
 422         for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
 423                 count++;
 424
 425         if (room <= 0 ||
 426             ((count >= FL_MAX_PER_SOCK ||
 427               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 428              !capable(CAP_NET_ADMIN)))
 429                 return -ENOBUFS;
 430
 431         return 0;
 432 }
 433
 434 static int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
 435 {
 436         if (h1 == h2)
 437                 return 0;
 438         if (h1 == NULL || h2 == NULL)
 439                 return 1;
 440         if (h1->hdrlen != h2->hdrlen)
 441                 return 1;
 442         return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
 443 }
 444
 445 static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
 446 {
 447         if (o1 == o2)
 448                 return 0;
 449         if (o1 == NULL || o2 == NULL)
 450                 return 1;
 451         if (o1->opt_nflen != o2->opt_nflen)
 452                 return 1;
 453         if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
 454                 return 1;
 455         if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
 456                 return 1;
 457         if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
 458                 return 1;
 459         return 0;
 460 }
 461
 462 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 463                 struct ip6_flowlabel *fl)
 464 {
 465         write_lock_bh(&ip6_sk_fl_lock);
 466         sfl->fl = fl;
 467         sfl->next = np->ipv6_fl_list;
 468         np->ipv6_fl_list = sfl;
 469         write_unlock_bh(&ip6_sk_fl_lock);
 470 }
 471
 472 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 473 {
 474         int uninitialized_var(err);
 475         struct net *net = sock_net(sk);
 476         struct ipv6_pinfo *np = inet6_sk(sk);
 477         struct in6_flowlabel_req freq;
 478         struct ipv6_fl_socklist *sfl1=NULL;
 479         struct ipv6_fl_socklist *sfl, **sflp;
 480         struct ip6_flowlabel *fl, *fl1 = NULL;
 481
 482
 483         if (optlen < sizeof(freq))
 484                 return -EINVAL;
 485
 486         if (copy_from_user(&freq, optval, sizeof(freq)))
 487                 return -EFAULT;
 488
 489         switch (freq.flr_action) {
 490         case IPV6_FL_A_PUT:
 491                 write_lock_bh(&ip6_sk_fl_lock);
 492                 for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
 493                         if (sfl->fl->label == freq.flr_label) {
 494                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 495                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 496                                 *sflp = sfl->next;
 497                                 write_unlock_bh(&ip6_sk_fl_lock);
 498                                 fl_release(sfl->fl);
 499                                 kfree(sfl);
 500                                 return 0;
 501                         }
 502                 }
 503                 write_unlock_bh(&ip6_sk_fl_lock);
 504                 return -ESRCH;
 505
 506         case IPV6_FL_A_RENEW:
 507                 read_lock_bh(&ip6_sk_fl_lock);
 508                 for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
 509                         if (sfl->fl->label == freq.flr_label) {
 510                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 511                                 read_unlock_bh(&ip6_sk_fl_lock);
 512                                 return err;
 513                         }
 514                 }
 515                 read_unlock_bh(&ip6_sk_fl_lock);
 516
 517                 if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
 518                         fl = fl_lookup(net, freq.flr_label);
 519                         if (fl) {
 520                                 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 521                                 fl_release(fl);
 522                                 return err;
 523                         }
 524                 }
 525                 return -ESRCH;
 526
 527         case IPV6_FL_A_GET:
 528                 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 529                         return -EINVAL;
 530
 531                 fl = fl_create(net, &freq, optval, optlen, &err);
 532                 if (fl == NULL)
 533                         return err;
 534                 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 535
 536                 if (freq.flr_label) {
 537                         err = -EEXIST;
 538                         read_lock_bh(&ip6_sk_fl_lock);
 539                         for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
 540                                 if (sfl->fl->label == freq.flr_label) {
 541                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
 542                                                 read_unlock_bh(&ip6_sk_fl_lock);
 543                                                 goto done;
 544                                         }
 545                                         fl1 = sfl->fl;
 546                                         atomic_inc(&fl1->users);
 547                                         break;
 548                                 }
 549                         }
 550                         read_unlock_bh(&ip6_sk_fl_lock);
 551
 552                         if (fl1 == NULL)
 553                                 fl1 = fl_lookup(net, freq.flr_label);
 554                         if (fl1) {
 555 recheck:
 556                                 err = -EEXIST;
 557                                 if (freq.flr_flags&IPV6_FL_F_EXCL)
 558                                         goto release;
 559                                 err = -EPERM;
 560                                 if (fl1->share == IPV6_FL_S_EXCL ||
 561                                     fl1->share != fl->share ||
 562                                     fl1->owner != fl->owner)
 563                                         goto release;
 564
 565                                 err = -EINVAL;
 566                                 if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
 567                                     ipv6_opt_cmp(fl1->opt, fl->opt))
 568                                         goto release;
 569
 570                                 err = -ENOMEM;
 571                                 if (sfl1 == NULL)
 572                                         goto release;
 573                                 if (fl->linger > fl1->linger)
 574                                         fl1->linger = fl->linger;
 575                                 if ((long)(fl->expires - fl1->expires) > 0)
 576                                         fl1->expires = fl->expires;
 577                                 fl_link(np, sfl1, fl1);
 578                                 fl_free(fl);
 579                                 return 0;
 580
 581 release:
 582                                 fl_release(fl1);
 583                                 goto done;
 584                         }
 585                 }
 586                 err = -ENOENT;
 587                 if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 588                         goto done;
 589
 590                 err = -ENOMEM;
 591                 if (sfl1 == NULL || (err = mem_check(sk)) != 0)
 592                         goto done;
 593
 594                 fl1 = fl_intern(net, fl, freq.flr_label);
 595                 if (fl1 != NULL)
 596                         goto recheck;
 597
 598                 if (!freq.flr_label) {
 599                         if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 600                                          &fl->label, sizeof(fl->label))) {
 601                                 /* Intentionally ignore fault. */
 602                         }
 603                 }
 604
 605                 fl_link(np, sfl1, fl);
 606                 return 0;
 607
 608         default:
 609                 return -EINVAL;
 610         }
 611
 612 done:
 613         fl_free(fl);
 614         kfree(sfl1);
 615         return err;
 616 }
 617
 618 #ifdef CONFIG_PROC_FS
 619
 620 struct ip6fl_iter_state {
 621         struct seq_net_private p;
 622         int bucket;
 623 };
 624
 625 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 626
 627 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 628 {
 629         struct ip6_flowlabel *fl = NULL;
 630         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 631         struct net *net = seq_file_net(seq);
 632
 633         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 634                 fl = fl_ht[state->bucket];
 635
 636                 while (fl && !net_eq(fl->fl_net, net))
 637                         fl = fl->next;
 638                 if (fl)
 639                         break;
 640         }
 641         return fl;
 642 }
 643
 644 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 645 {
 646         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 647         struct net *net = seq_file_net(seq);
 648
 649         fl = fl->next;
 650 try_again:
 651         while (fl && !net_eq(fl->fl_net, net))
 652                 fl = fl->next;
 653
 654         while (!fl) {
 655                 if (++state->bucket <= FL_HASH_MASK) {
 656                         fl = fl_ht[state->bucket];
 657                         goto try_again;
 658                 } else
 659                         break;
 660         }
 661         return fl;
 662 }
 663
 664 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 665 {
 666         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 667         if (fl)
 668                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 669                         --pos;
 670         return pos ? NULL : fl;
 671 }
 672
 673 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 674         __acquires(ip6_fl_lock)
 675 {
 676         read_lock_bh(&ip6_fl_lock);
 677         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 678 }
 679
 680 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 681 {
 682         struct ip6_flowlabel *fl;
 683
 684         if (v == SEQ_START_TOKEN)
 685                 fl = ip6fl_get_first(seq);
 686         else
 687                 fl = ip6fl_get_next(seq, v);
 688         ++*pos;
 689         return fl;
 690 }
 691
 692 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 693         __releases(ip6_fl_lock)
 694 {
 695         read_unlock_bh(&ip6_fl_lock);
 696 }
 697
 698 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 699 {
 700         if (v == SEQ_START_TOKEN)
 701                 seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
 702                            "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
 703         else {
 704                 struct ip6_flowlabel *fl = v;
 705                 seq_printf(seq,
 706                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 707                            (unsigned)ntohl(fl->label),
 708                            fl->share,
 709                            (unsigned)fl->owner,
 710                            atomic_read(&fl->users),
 711                            fl->linger/HZ,
 712                            (long)(fl->expires - jiffies)/HZ,
 713                            &fl->dst,
 714                            fl->opt ? fl->opt->opt_nflen : 0);
 715         }
 716         return 0;
 717 }
 718
 719 static const struct seq_operations ip6fl_seq_ops = {
 720         .start  =       ip6fl_seq_start,
 721         .next   =       ip6fl_seq_next,
 722         .stop   =       ip6fl_seq_stop,
 723         .show   =       ip6fl_seq_show,
 724 };
 725
 726 static int ip6fl_seq_open(struct inode *inode, struct file *file)
 727 {
 728         return seq_open_net(inode, file, &ip6fl_seq_ops,
 729                             sizeof(struct ip6fl_iter_state));
 730 }
 731
 732 static const struct file_operations ip6fl_seq_fops = {
 733         .owner          =       THIS_MODULE,
 734         .open           =       ip6fl_seq_open,
 735         .read           =       seq_read,
 736         .llseek         =       seq_lseek,
 737         .release        =       seq_release_net,
 738 };
 739
 740 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 741 {
 742         if (!proc_net_fops_create(net, "ip6_flowlabel",
 743                                   S_IRUGO, &ip6fl_seq_fops))
 744                 return -ENOMEM;
 745         return 0;
 746 }
 747
 748 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 749 {
 750         proc_net_remove(net, "ip6_flowlabel");
 751 }
 752 #else
 753 static inline int ip6_flowlabel_proc_init(struct net *net)
 754 {
 755         return 0;
 756 }
 757 static inline void ip6_flowlabel_proc_fini(struct net *net)
 758 {
 759 }
 760 #endif
 761
 762 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 763 {
 764         ip6_fl_purge(net);
 765         ip6_flowlabel_proc_fini(net);
 766 }
 767
 768 static struct pernet_operations ip6_flowlabel_net_ops = {
 769         .init = ip6_flowlabel_proc_init,
 770         .exit = ip6_flowlabel_net_exit,
 771 };
 772
 773 int ip6_flowlabel_init(void)
 774 {
 775         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 776 }
 777
 778 void ip6_flowlabel_cleanup(void)
 779 {
 780         del_timer(&ip6_fl_gc_timer);
 781         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 782 }