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, &junk);
 364                 if (err)
 365                         goto done;
 366                 err = -EINVAL;
 367                 if (fl->opt->opt_flen)
 368                         goto done;
 369                 if (fl->opt->opt_nflen == 0) {
 370                         kfree(fl->opt);
 371                         fl->opt = NULL;
 372                 }
 373         }
 374
 375         fl->fl_net = hold_net(net);
 376         fl->expires = jiffies;
 377         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 378         if (err)
 379                 goto done;
 380         fl->share = freq->flr_share;
 381         addr_type = ipv6_addr_type(&freq->flr_dst);
 382         if ((addr_type & IPV6_ADDR_MAPPED) ||
 383             addr_type == IPV6_ADDR_ANY) {
 384                 err = -EINVAL;
 385                 goto done;
 386         }
 387         ipv6_addr_copy(&fl->dst, &freq->flr_dst);
 388         atomic_set(&fl->users, 1);
 389         switch (fl->share) {
 390         case IPV6_FL_S_EXCL:
 391         case IPV6_FL_S_ANY:
 392                 break;
 393         case IPV6_FL_S_PROCESS:
 394                 fl->owner = current->pid;
 395                 break;
 396         case IPV6_FL_S_USER:
 397                 fl->owner = current_euid();
 398                 break;
 399         default:
 400                 err = -EINVAL;
 401                 goto done;
 402         }
 403         return fl;
 404
 405 done:
 406         fl_free(fl);
 407         *err_p = err;
 408         return NULL;
 409 }
 410
 411 static int mem_check(struct sock *sk)
 412 {
 413         struct ipv6_pinfo *np = inet6_sk(sk);
 414         struct ipv6_fl_socklist *sfl;
 415         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 416         int count = 0;
 417
 418         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 419                 return 0;
 420
 421         for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
 422                 count++;
 423
 424         if (room <= 0 ||
 425             ((count >= FL_MAX_PER_SOCK ||
 426               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 427              !capable(CAP_NET_ADMIN)))
 428                 return -ENOBUFS;
 429
 430         return 0;
 431 }
 432
 433 static int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2)
 434 {
 435         if (h1 == h2)
 436                 return 0;
 437         if (h1 == NULL || h2 == NULL)
 438                 return 1;
 439         if (h1->hdrlen != h2->hdrlen)
 440                 return 1;
 441         return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1));
 442 }
 443
 444 static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
 445 {
 446         if (o1 == o2)
 447                 return 0;
 448         if (o1 == NULL || o2 == NULL)
 449                 return 1;
 450         if (o1->opt_nflen != o2->opt_nflen)
 451                 return 1;
 452         if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt))
 453                 return 1;
 454         if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt))
 455                 return 1;
 456         if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt))
 457                 return 1;
 458         return 0;
 459 }
 460
 461 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 462                 struct ip6_flowlabel *fl)
 463 {
 464         write_lock_bh(&ip6_sk_fl_lock);
 465         sfl->fl = fl;
 466         sfl->next = np->ipv6_fl_list;
 467         np->ipv6_fl_list = sfl;
 468         write_unlock_bh(&ip6_sk_fl_lock);
 469 }
 470
 471 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 472 {
 473         int uninitialized_var(err);
 474         struct net *net = sock_net(sk);
 475         struct ipv6_pinfo *np = inet6_sk(sk);
 476         struct in6_flowlabel_req freq;
 477         struct ipv6_fl_socklist *sfl1=NULL;
 478         struct ipv6_fl_socklist *sfl, **sflp;
 479         struct ip6_flowlabel *fl, *fl1 = NULL;
 480
 481
 482         if (optlen < sizeof(freq))
 483                 return -EINVAL;
 484
 485         if (copy_from_user(&freq, optval, sizeof(freq)))
 486                 return -EFAULT;
 487
 488         switch (freq.flr_action) {
 489         case IPV6_FL_A_PUT:
 490                 write_lock_bh(&ip6_sk_fl_lock);
 491                 for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
 492                         if (sfl->fl->label == freq.flr_label) {
 493                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 494                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 495                                 *sflp = sfl->next;
 496                                 write_unlock_bh(&ip6_sk_fl_lock);
 497                                 fl_release(sfl->fl);
 498                                 kfree(sfl);
 499                                 return 0;
 500                         }
 501                 }
 502                 write_unlock_bh(&ip6_sk_fl_lock);
 503                 return -ESRCH;
 504
 505         case IPV6_FL_A_RENEW:
 506                 read_lock_bh(&ip6_sk_fl_lock);
 507                 for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
 508                         if (sfl->fl->label == freq.flr_label) {
 509                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 510                                 read_unlock_bh(&ip6_sk_fl_lock);
 511                                 return err;
 512                         }
 513                 }
 514                 read_unlock_bh(&ip6_sk_fl_lock);
 515
 516                 if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) {
 517                         fl = fl_lookup(net, freq.flr_label);
 518                         if (fl) {
 519                                 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 520                                 fl_release(fl);
 521                                 return err;
 522                         }
 523                 }
 524                 return -ESRCH;
 525
 526         case IPV6_FL_A_GET:
 527                 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 528                         return -EINVAL;
 529
 530                 fl = fl_create(net, &freq, optval, optlen, &err);
 531                 if (fl == NULL)
 532                         return err;
 533                 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 534
 535                 if (freq.flr_label) {
 536                         err = -EEXIST;
 537                         read_lock_bh(&ip6_sk_fl_lock);
 538                         for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
 539                                 if (sfl->fl->label == freq.flr_label) {
 540                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
 541                                                 read_unlock_bh(&ip6_sk_fl_lock);
 542                                                 goto done;
 543                                         }
 544                                         fl1 = sfl->fl;
 545                                         atomic_inc(&fl1->users);
 546                                         break;
 547                                 }
 548                         }
 549                         read_unlock_bh(&ip6_sk_fl_lock);
 550
 551                         if (fl1 == NULL)
 552                                 fl1 = fl_lookup(net, freq.flr_label);
 553                         if (fl1) {
 554 recheck:
 555                                 err = -EEXIST;
 556                                 if (freq.flr_flags&IPV6_FL_F_EXCL)
 557                                         goto release;
 558                                 err = -EPERM;
 559                                 if (fl1->share == IPV6_FL_S_EXCL ||
 560                                     fl1->share != fl->share ||
 561                                     fl1->owner != fl->owner)
 562                                         goto release;
 563
 564                                 err = -EINVAL;
 565                                 if (!ipv6_addr_equal(&fl1->dst, &fl->dst) ||
 566                                     ipv6_opt_cmp(fl1->opt, fl->opt))
 567                                         goto release;
 568
 569                                 err = -ENOMEM;
 570                                 if (sfl1 == NULL)
 571                                         goto release;
 572                                 if (fl->linger > fl1->linger)
 573                                         fl1->linger = fl->linger;
 574                                 if ((long)(fl->expires - fl1->expires) > 0)
 575                                         fl1->expires = fl->expires;
 576                                 fl_link(np, sfl1, fl1);
 577                                 fl_free(fl);
 578                                 return 0;
 579
 580 release:
 581                                 fl_release(fl1);
 582                                 goto done;
 583                         }
 584                 }
 585                 err = -ENOENT;
 586                 if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 587                         goto done;
 588
 589                 err = -ENOMEM;
 590                 if (sfl1 == NULL || (err = mem_check(sk)) != 0)
 591                         goto done;
 592
 593                 fl1 = fl_intern(net, fl, freq.flr_label);
 594                 if (fl1 != NULL)
 595                         goto recheck;
 596
 597                 if (!freq.flr_label) {
 598                         if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 599                                          &fl->label, sizeof(fl->label))) {
 600                                 /* Intentionally ignore fault. */
 601                         }
 602                 }
 603
 604                 fl_link(np, sfl1, fl);
 605                 return 0;
 606
 607         default:
 608                 return -EINVAL;
 609         }
 610
 611 done:
 612         fl_free(fl);
 613         kfree(sfl1);
 614         return err;
 615 }
 616
 617 #ifdef CONFIG_PROC_FS
 618
 619 struct ip6fl_iter_state {
 620         struct seq_net_private p;
 621         int bucket;
 622 };
 623
 624 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 625
 626 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 627 {
 628         struct ip6_flowlabel *fl = NULL;
 629         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 630         struct net *net = seq_file_net(seq);
 631
 632         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 633                 fl = fl_ht[state->bucket];
 634
 635                 while (fl && !net_eq(fl->fl_net, net))
 636                         fl = fl->next;
 637                 if (fl)
 638                         break;
 639         }
 640         return fl;
 641 }
 642
 643 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 644 {
 645         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 646         struct net *net = seq_file_net(seq);
 647
 648         fl = fl->next;
 649 try_again:
 650         while (fl && !net_eq(fl->fl_net, net))
 651                 fl = fl->next;
 652
 653         while (!fl) {
 654                 if (++state->bucket <= FL_HASH_MASK) {
 655                         fl = fl_ht[state->bucket];
 656                         goto try_again;
 657                 } else
 658                         break;
 659         }
 660         return fl;
 661 }
 662
 663 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 664 {
 665         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 666         if (fl)
 667                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 668                         --pos;
 669         return pos ? NULL : fl;
 670 }
 671
 672 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 673         __acquires(ip6_fl_lock)
 674 {
 675         read_lock_bh(&ip6_fl_lock);
 676         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 677 }
 678
 679 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 680 {
 681         struct ip6_flowlabel *fl;
 682
 683         if (v == SEQ_START_TOKEN)
 684                 fl = ip6fl_get_first(seq);
 685         else
 686                 fl = ip6fl_get_next(seq, v);
 687         ++*pos;
 688         return fl;
 689 }
 690
 691 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 692         __releases(ip6_fl_lock)
 693 {
 694         read_unlock_bh(&ip6_fl_lock);
 695 }
 696
 697 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 698 {
 699         if (v == SEQ_START_TOKEN)
 700                 seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
 701                            "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
 702         else {
 703                 struct ip6_flowlabel *fl = v;
 704                 seq_printf(seq,
 705                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 706                            (unsigned)ntohl(fl->label),
 707                            fl->share,
 708                            (unsigned)fl->owner,
 709                            atomic_read(&fl->users),
 710                            fl->linger/HZ,
 711                            (long)(fl->expires - jiffies)/HZ,
 712                            &fl->dst,
 713                            fl->opt ? fl->opt->opt_nflen : 0);
 714         }
 715         return 0;
 716 }
 717
 718 static const struct seq_operations ip6fl_seq_ops = {
 719         .start  =       ip6fl_seq_start,
 720         .next   =       ip6fl_seq_next,
 721         .stop   =       ip6fl_seq_stop,
 722         .show   =       ip6fl_seq_show,
 723 };
 724
 725 static int ip6fl_seq_open(struct inode *inode, struct file *file)
 726 {
 727         return seq_open_net(inode, file, &ip6fl_seq_ops,
 728                             sizeof(struct ip6fl_iter_state));
 729 }
 730
 731 static const struct file_operations ip6fl_seq_fops = {
 732         .owner          =       THIS_MODULE,
 733         .open           =       ip6fl_seq_open,
 734         .read           =       seq_read,
 735         .llseek         =       seq_lseek,
 736         .release        =       seq_release_net,
 737 };
 738
 739 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 740 {
 741         if (!proc_net_fops_create(net, "ip6_flowlabel",
 742                                   S_IRUGO, &ip6fl_seq_fops))
 743                 return -ENOMEM;
 744         return 0;
 745 }
 746
 747 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 748 {
 749         proc_net_remove(net, "ip6_flowlabel");
 750 }
 751 #else
 752 static inline int ip6_flowlabel_proc_init(struct net *net)
 753 {
 754         return 0;
 755 }
 756 static inline void ip6_flowlabel_proc_fini(struct net *net)
 757 {
 758 }
 759 #endif
 760
 761 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 762 {
 763         ip6_fl_purge(net);
 764         ip6_flowlabel_proc_fini(net);
 765 }
 766
 767 static struct pernet_operations ip6_flowlabel_net_ops = {
 768         .init = ip6_flowlabel_proc_init,
 769         .exit = ip6_flowlabel_net_exit,
 770 };
 771
 772 int ip6_flowlabel_init(void)
 773 {
 774         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 775 }
 776
 777 void ip6_flowlabel_cleanup(void)
 778 {
 779         del_timer(&ip6_fl_gc_timer);
 780         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 781 }