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   150     /* 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(prandom_u32())&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
 349         spin_lock_bh(&ip6_fl_lock);
 350         fl->lastuse = jiffies;
 351         if (time_before(fl->linger, linger))
 352                 fl->linger = linger;
 353         if (time_before(expires, fl->linger))
 354                 expires = fl->linger;
 355         if (time_before(fl->expires, fl->lastuse + expires))
 356                 fl->expires = fl->lastuse + expires;
 357         spin_unlock_bh(&ip6_fl_lock);
 358
 359         return 0;
 360 }
 361
 362 static struct ip6_flowlabel *
 363 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 364           char __user *optval, int optlen, int *err_p)
 365 {
 366         struct ip6_flowlabel *fl = NULL;
 367         int olen;
 368         int addr_type;
 369         int err;
 370
 371         olen = optlen - CMSG_ALIGN(sizeof(*freq));
 372         err = -EINVAL;
 373         if (olen > 64 * 1024)
 374                 goto done;
 375
 376         err = -ENOMEM;
 377         fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 378         if (fl == NULL)
 379                 goto done;
 380
 381         if (olen > 0) {
 382                 struct msghdr msg;
 383                 struct flowi6 flowi6;
 384                 int junk;
 385
 386                 err = -ENOMEM;
 387                 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 388                 if (fl->opt == NULL)
 389                         goto done;
 390
 391                 memset(fl->opt, 0, sizeof(*fl->opt));
 392                 fl->opt->tot_len = sizeof(*fl->opt) + olen;
 393                 err = -EFAULT;
 394                 if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
 395                         goto done;
 396
 397                 msg.msg_controllen = olen;
 398                 msg.msg_control = (void*)(fl->opt+1);
 399                 memset(&flowi6, 0, sizeof(flowi6));
 400
 401                 err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, fl->opt,
 402                                             &junk, &junk, &junk);
 403                 if (err)
 404                         goto done;
 405                 err = -EINVAL;
 406                 if (fl->opt->opt_flen)
 407                         goto done;
 408                 if (fl->opt->opt_nflen == 0) {
 409                         kfree(fl->opt);
 410                         fl->opt = NULL;
 411                 }
 412         }
 413
 414         fl->fl_net = hold_net(net);
 415         fl->expires = jiffies;
 416         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 417         if (err)
 418                 goto done;
 419         fl->share = freq->flr_share;
 420         addr_type = ipv6_addr_type(&freq->flr_dst);
 421         if ((addr_type & IPV6_ADDR_MAPPED) ||
 422             addr_type == IPV6_ADDR_ANY) {
 423                 err = -EINVAL;
 424                 goto done;
 425         }
 426         fl->dst = freq->flr_dst;
 427         atomic_set(&fl->users, 1);
 428         switch (fl->share) {
 429         case IPV6_FL_S_EXCL:
 430         case IPV6_FL_S_ANY:
 431                 break;
 432         case IPV6_FL_S_PROCESS:
 433                 fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 434                 break;
 435         case IPV6_FL_S_USER:
 436                 fl->owner.uid = current_euid();
 437                 break;
 438         default:
 439                 err = -EINVAL;
 440                 goto done;
 441         }
 442         return fl;
 443
 444 done:
 445         fl_free(fl);
 446         *err_p = err;
 447         return NULL;
 448 }
 449
 450 static int mem_check(struct sock *sk)
 451 {
 452         struct ipv6_pinfo *np = inet6_sk(sk);
 453         struct ipv6_fl_socklist *sfl;
 454         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 455         int count = 0;
 456
 457         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 458                 return 0;
 459
 460         rcu_read_lock_bh();
 461         for_each_sk_fl_rcu(np, sfl)
 462                 count++;
 463         rcu_read_unlock_bh();
 464
 465         if (room <= 0 ||
 466             ((count >= FL_MAX_PER_SOCK ||
 467               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 468              !capable(CAP_NET_ADMIN)))
 469                 return -ENOBUFS;
 470
 471         return 0;
 472 }
 473
 474 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 475                 struct ip6_flowlabel *fl)
 476 {
 477         spin_lock_bh(&ip6_sk_fl_lock);
 478         sfl->fl = fl;
 479         sfl->next = np->ipv6_fl_list;
 480         rcu_assign_pointer(np->ipv6_fl_list, sfl);
 481         spin_unlock_bh(&ip6_sk_fl_lock);
 482 }
 483
 484 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 485                            int flags)
 486 {
 487         struct ipv6_pinfo *np = inet6_sk(sk);
 488         struct ipv6_fl_socklist *sfl;
 489
 490         if (flags & IPV6_FL_F_REMOTE) {
 491                 freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 492                 return 0;
 493         }
 494
 495         if (np->repflow) {
 496                 freq->flr_label = np->flow_label;
 497                 return 0;
 498         }
 499
 500         rcu_read_lock_bh();
 501
 502         for_each_sk_fl_rcu(np, sfl) {
 503                 if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 504                         spin_lock_bh(&ip6_fl_lock);
 505                         freq->flr_label = sfl->fl->label;
 506                         freq->flr_dst = sfl->fl->dst;
 507                         freq->flr_share = sfl->fl->share;
 508                         freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 509                         freq->flr_linger = sfl->fl->linger / HZ;
 510
 511                         spin_unlock_bh(&ip6_fl_lock);
 512                         rcu_read_unlock_bh();
 513                         return 0;
 514                 }
 515         }
 516         rcu_read_unlock_bh();
 517
 518         return -ENOENT;
 519 }
 520
 521 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 522 {
 523         int uninitialized_var(err);
 524         struct net *net = sock_net(sk);
 525         struct ipv6_pinfo *np = inet6_sk(sk);
 526         struct in6_flowlabel_req freq;
 527         struct ipv6_fl_socklist *sfl1=NULL;
 528         struct ipv6_fl_socklist *sfl;
 529         struct ipv6_fl_socklist __rcu **sflp;
 530         struct ip6_flowlabel *fl, *fl1 = NULL;
 531
 532
 533         if (optlen < sizeof(freq))
 534                 return -EINVAL;
 535
 536         if (copy_from_user(&freq, optval, sizeof(freq)))
 537                 return -EFAULT;
 538
 539         switch (freq.flr_action) {
 540         case IPV6_FL_A_PUT:
 541                 if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 542                         if (sk->sk_protocol != IPPROTO_TCP)
 543                                 return -ENOPROTOOPT;
 544                         if (!np->repflow)
 545                                 return -ESRCH;
 546                         np->flow_label = 0;
 547                         np->repflow = 0;
 548                         return 0;
 549                 }
 550                 spin_lock_bh(&ip6_sk_fl_lock);
 551                 for (sflp = &np->ipv6_fl_list;
 552                      (sfl = rcu_dereference(*sflp))!=NULL;
 553                      sflp = &sfl->next) {
 554                         if (sfl->fl->label == freq.flr_label) {
 555                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 556                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 557                                 *sflp = rcu_dereference(sfl->next);
 558                                 spin_unlock_bh(&ip6_sk_fl_lock);
 559                                 fl_release(sfl->fl);
 560                                 kfree_rcu(sfl, rcu);
 561                                 return 0;
 562                         }
 563                 }
 564                 spin_unlock_bh(&ip6_sk_fl_lock);
 565                 return -ESRCH;
 566
 567         case IPV6_FL_A_RENEW:
 568                 rcu_read_lock_bh();
 569                 for_each_sk_fl_rcu(np, sfl) {
 570                         if (sfl->fl->label == freq.flr_label) {
 571                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 572                                 rcu_read_unlock_bh();
 573                                 return err;
 574                         }
 575                 }
 576                 rcu_read_unlock_bh();
 577
 578                 if (freq.flr_share == IPV6_FL_S_NONE &&
 579                     ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 580                         fl = fl_lookup(net, freq.flr_label);
 581                         if (fl) {
 582                                 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 583                                 fl_release(fl);
 584                                 return err;
 585                         }
 586                 }
 587                 return -ESRCH;
 588
 589         case IPV6_FL_A_GET:
 590                 if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 591                         struct net *net = sock_net(sk);
 592                         if (net->ipv6.sysctl.flowlabel_consistency) {
 593                                 net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 594                                 return -EPERM;
 595                         }
 596
 597                         if (sk->sk_protocol != IPPROTO_TCP)
 598                                 return -ENOPROTOOPT;
 599
 600                         np->repflow = 1;
 601                         return 0;
 602                 }
 603
 604                 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 605                         return -EINVAL;
 606
 607                 fl = fl_create(net, sk, &freq, optval, optlen, &err);
 608                 if (fl == NULL)
 609                         return err;
 610                 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 611
 612                 if (freq.flr_label) {
 613                         err = -EEXIST;
 614                         rcu_read_lock_bh();
 615                         for_each_sk_fl_rcu(np, sfl) {
 616                                 if (sfl->fl->label == freq.flr_label) {
 617                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
 618                                                 rcu_read_unlock_bh();
 619                                                 goto done;
 620                                         }
 621                                         fl1 = sfl->fl;
 622                                         atomic_inc(&fl1->users);
 623                                         break;
 624                                 }
 625                         }
 626                         rcu_read_unlock_bh();
 627
 628                         if (fl1 == NULL)
 629                                 fl1 = fl_lookup(net, freq.flr_label);
 630                         if (fl1) {
 631 recheck:
 632                                 err = -EEXIST;
 633                                 if (freq.flr_flags&IPV6_FL_F_EXCL)
 634                                         goto release;
 635                                 err = -EPERM;
 636                                 if (fl1->share == IPV6_FL_S_EXCL ||
 637                                     fl1->share != fl->share ||
 638                                     ((fl1->share == IPV6_FL_S_PROCESS) &&
 639                                      (fl1->owner.pid == fl->owner.pid)) ||
 640                                     ((fl1->share == IPV6_FL_S_USER) &&
 641                                      uid_eq(fl1->owner.uid, fl->owner.uid)))
 642                                         goto release;
 643
 644                                 err = -ENOMEM;
 645                                 if (sfl1 == NULL)
 646                                         goto release;
 647                                 if (fl->linger > fl1->linger)
 648                                         fl1->linger = fl->linger;
 649                                 if ((long)(fl->expires - fl1->expires) > 0)
 650                                         fl1->expires = fl->expires;
 651                                 fl_link(np, sfl1, fl1);
 652                                 fl_free(fl);
 653                                 return 0;
 654
 655 release:
 656                                 fl_release(fl1);
 657                                 goto done;
 658                         }
 659                 }
 660                 err = -ENOENT;
 661                 if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 662                         goto done;
 663
 664                 err = -ENOMEM;
 665                 if (sfl1 == NULL || (err = mem_check(sk)) != 0)
 666                         goto done;
 667
 668                 fl1 = fl_intern(net, fl, freq.flr_label);
 669                 if (fl1 != NULL)
 670                         goto recheck;
 671
 672                 if (!freq.flr_label) {
 673                         if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 674                                          &fl->label, sizeof(fl->label))) {
 675                                 /* Intentionally ignore fault. */
 676                         }
 677                 }
 678
 679                 fl_link(np, sfl1, fl);
 680                 return 0;
 681
 682         default:
 683                 return -EINVAL;
 684         }
 685
 686 done:
 687         fl_free(fl);
 688         kfree(sfl1);
 689         return err;
 690 }
 691
 692 #ifdef CONFIG_PROC_FS
 693
 694 struct ip6fl_iter_state {
 695         struct seq_net_private p;
 696         struct pid_namespace *pid_ns;
 697         int bucket;
 698 };
 699
 700 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 701
 702 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 703 {
 704         struct ip6_flowlabel *fl = NULL;
 705         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 706         struct net *net = seq_file_net(seq);
 707
 708         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 709                 for_each_fl_rcu(state->bucket, fl) {
 710                         if (net_eq(fl->fl_net, net))
 711                                 goto out;
 712                 }
 713         }
 714         fl = NULL;
 715 out:
 716         return fl;
 717 }
 718
 719 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 720 {
 721         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 722         struct net *net = seq_file_net(seq);
 723
 724         for_each_fl_continue_rcu(fl) {
 725                 if (net_eq(fl->fl_net, net))
 726                         goto out;
 727         }
 728
 729 try_again:
 730         if (++state->bucket <= FL_HASH_MASK) {
 731                 for_each_fl_rcu(state->bucket, fl) {
 732                         if (net_eq(fl->fl_net, net))
 733                                 goto out;
 734                 }
 735                 goto try_again;
 736         }
 737         fl = NULL;
 738
 739 out:
 740         return fl;
 741 }
 742
 743 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 744 {
 745         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 746         if (fl)
 747                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 748                         --pos;
 749         return pos ? NULL : fl;
 750 }
 751
 752 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 753         __acquires(RCU)
 754 {
 755         rcu_read_lock_bh();
 756         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 757 }
 758
 759 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 760 {
 761         struct ip6_flowlabel *fl;
 762
 763         if (v == SEQ_START_TOKEN)
 764                 fl = ip6fl_get_first(seq);
 765         else
 766                 fl = ip6fl_get_next(seq, v);
 767         ++*pos;
 768         return fl;
 769 }
 770
 771 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 772         __releases(RCU)
 773 {
 774         rcu_read_unlock_bh();
 775 }
 776
 777 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 778 {
 779         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 780         if (v == SEQ_START_TOKEN)
 781                 seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
 782                            "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
 783         else {
 784                 struct ip6_flowlabel *fl = v;
 785                 seq_printf(seq,
 786                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 787                            (unsigned int)ntohl(fl->label),
 788                            fl->share,
 789                            ((fl->share == IPV6_FL_S_PROCESS) ?
 790                             pid_nr_ns(fl->owner.pid, state->pid_ns) :
 791                             ((fl->share == IPV6_FL_S_USER) ?
 792                              from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 793                              0)),
 794                            atomic_read(&fl->users),
 795                            fl->linger/HZ,
 796                            (long)(fl->expires - jiffies)/HZ,
 797                            &fl->dst,
 798                            fl->opt ? fl->opt->opt_nflen : 0);
 799         }
 800         return 0;
 801 }
 802
 803 static const struct seq_operations ip6fl_seq_ops = {
 804         .start  =       ip6fl_seq_start,
 805         .next   =       ip6fl_seq_next,
 806         .stop   =       ip6fl_seq_stop,
 807         .show   =       ip6fl_seq_show,
 808 };
 809
 810 static int ip6fl_seq_open(struct inode *inode, struct file *file)
 811 {
 812         struct seq_file *seq;
 813         struct ip6fl_iter_state *state;
 814         int err;
 815
 816         err = seq_open_net(inode, file, &ip6fl_seq_ops,
 817                            sizeof(struct ip6fl_iter_state));
 818
 819         if (!err) {
 820                 seq = file->private_data;
 821                 state = ip6fl_seq_private(seq);
 822                 rcu_read_lock();
 823                 state->pid_ns = get_pid_ns(task_active_pid_ns(current));
 824                 rcu_read_unlock();
 825         }
 826         return err;
 827 }
 828
 829 static int ip6fl_seq_release(struct inode *inode, struct file *file)
 830 {
 831         struct seq_file *seq = file->private_data;
 832         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 833         put_pid_ns(state->pid_ns);
 834         return seq_release_net(inode, file);
 835 }
 836
 837 static const struct file_operations ip6fl_seq_fops = {
 838         .owner          =       THIS_MODULE,
 839         .open           =       ip6fl_seq_open,
 840         .read           =       seq_read,
 841         .llseek         =       seq_lseek,
 842         .release        =       ip6fl_seq_release,
 843 };
 844
 845 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 846 {
 847         if (!proc_create("ip6_flowlabel", S_IRUGO, net->proc_net,
 848                          &ip6fl_seq_fops))
 849                 return -ENOMEM;
 850         return 0;
 851 }
 852
 853 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 854 {
 855         remove_proc_entry("ip6_flowlabel", net->proc_net);
 856 }
 857 #else
 858 static inline int ip6_flowlabel_proc_init(struct net *net)
 859 {
 860         return 0;
 861 }
 862 static inline void ip6_flowlabel_proc_fini(struct net *net)
 863 {
 864 }
 865 #endif
 866
 867 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 868 {
 869         ip6_fl_purge(net);
 870         ip6_flowlabel_proc_fini(net);
 871 }
 872
 873 static struct pernet_operations ip6_flowlabel_net_ops = {
 874         .init = ip6_flowlabel_proc_init,
 875         .exit = ip6_flowlabel_net_exit,
 876 };
 877
 878 int ip6_flowlabel_init(void)
 879 {
 880         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 881 }
 882
 883 void ip6_flowlabel_cleanup(void)
 884 {
 885         del_timer(&ip6_fl_gc_timer);
 886         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 887 }