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/in6.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/slab.h>
  22 #include <linux/export.h>
  23 #include <linux/pid_namespace.h>
  24
  25 #include <net/net_namespace.h>
  26 #include <net/sock.h>
  27
  28 #include <net/ipv6.h>
  29 #include <net/rawv6.h>
  30 #include <net/transp_v6.h>
  31
  32 #include <asm/uaccess.h>
  33
  34 #define FL_MIN_LINGER   6       /* Minimal linger. It is set to 6sec specified
  35                                    in old IPv6 RFC. Well, it was reasonable value.
  36                                  */
  37 #define FL_MAX_LINGER   150     /* Maximal linger timeout */
  38
  39 /* FL hash table */
  40
  41 #define FL_MAX_PER_SOCK 32
  42 #define FL_MAX_SIZE     4096
  43 #define FL_HASH_MASK    255
  44 #define FL_HASH(l)      (ntohl(l)&FL_HASH_MASK)
  45
  46 static atomic_t fl_size = ATOMIC_INIT(0);
  47 static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
  48
  49 static void ip6_fl_gc(unsigned long dummy);
  50 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0);
  51
  52 /* FL hash table lock: it protects only of GC */
  53
  54 static DEFINE_SPINLOCK(ip6_fl_lock);
  55
  56 /* Big socket sock */
  57
  58 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
  59
  60 #define for_each_fl_rcu(hash, fl)                               \
  61         for (fl = rcu_dereference_bh(fl_ht[(hash)]);            \
  62              fl != NULL;                                        \
  63              fl = rcu_dereference_bh(fl->next))
  64 #define for_each_fl_continue_rcu(fl)                            \
  65         for (fl = rcu_dereference_bh(fl->next);                 \
  66              fl != NULL;                                        \
  67              fl = rcu_dereference_bh(fl->next))
  68
  69 #define for_each_sk_fl_rcu(np, sfl)                             \
  70         for (sfl = rcu_dereference_bh(np->ipv6_fl_list);        \
  71              sfl != NULL;                                       \
  72              sfl = rcu_dereference_bh(sfl->next))
  73
  74 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
  75 {
  76         struct ip6_flowlabel *fl;
  77
  78         for_each_fl_rcu(FL_HASH(label), fl) {
  79                 if (fl->label == label && net_eq(fl->fl_net, net))
  80                         return fl;
  81         }
  82         return NULL;
  83 }
  84
  85 static struct ip6_flowlabel *fl_lookup(struct net *net, __be32 label)
  86 {
  87         struct ip6_flowlabel *fl;
  88
  89         rcu_read_lock_bh();
  90         fl = __fl_lookup(net, label);
  91         if (fl && !atomic_inc_not_zero(&fl->users))
  92                 fl = NULL;
  93         rcu_read_unlock_bh();
  94         return fl;
  95 }
  96
  97
  98 static void fl_free(struct ip6_flowlabel *fl)
  99 {
 100         if (fl) {
 101                 if (fl->share == IPV6_FL_S_PROCESS)
 102                         put_pid(fl->owner.pid);
 103                 kfree(fl->opt);
 104                 kfree_rcu(fl, rcu);
 105         }
 106 }
 107
 108 static void fl_release(struct ip6_flowlabel *fl)
 109 {
 110         spin_lock_bh(&ip6_fl_lock);
 111
 112         fl->lastuse = jiffies;
 113         if (atomic_dec_and_test(&fl->users)) {
 114                 unsigned long ttd = fl->lastuse + fl->linger;
 115                 if (time_after(ttd, fl->expires))
 116                         fl->expires = ttd;
 117                 ttd = fl->expires;
 118                 if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
 119                         struct ipv6_txoptions *opt = fl->opt;
 120                         fl->opt = NULL;
 121                         kfree(opt);
 122                 }
 123                 if (!timer_pending(&ip6_fl_gc_timer) ||
 124                     time_after(ip6_fl_gc_timer.expires, ttd))
 125                         mod_timer(&ip6_fl_gc_timer, ttd);
 126         }
 127         spin_unlock_bh(&ip6_fl_lock);
 128 }
 129
 130 static void ip6_fl_gc(unsigned long dummy)
 131 {
 132         int i;
 133         unsigned long now = jiffies;
 134         unsigned long sched = 0;
 135
 136         spin_lock(&ip6_fl_lock);
 137
 138         for (i = 0; i <= FL_HASH_MASK; i++) {
 139                 struct ip6_flowlabel *fl;
 140                 struct ip6_flowlabel __rcu **flp;
 141
 142                 flp = &fl_ht[i];
 143                 while ((fl = rcu_dereference_protected(*flp,
 144                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 145                         if (atomic_read(&fl->users) == 0) {
 146                                 unsigned long ttd = fl->lastuse + fl->linger;
 147                                 if (time_after(ttd, fl->expires))
 148                                         fl->expires = ttd;
 149                                 ttd = fl->expires;
 150                                 if (time_after_eq(now, ttd)) {
 151                                         *flp = fl->next;
 152                                         fl_free(fl);
 153                                         atomic_dec(&fl_size);
 154                                         continue;
 155                                 }
 156                                 if (!sched || time_before(ttd, sched))
 157                                         sched = ttd;
 158                         }
 159                         flp = &fl->next;
 160                 }
 161         }
 162         if (!sched && atomic_read(&fl_size))
 163                 sched = now + FL_MAX_LINGER;
 164         if (sched) {
 165                 mod_timer(&ip6_fl_gc_timer, sched);
 166         }
 167         spin_unlock(&ip6_fl_lock);
 168 }
 169
 170 static void __net_exit ip6_fl_purge(struct net *net)
 171 {
 172         int i;
 173
 174         spin_lock_bh(&ip6_fl_lock);
 175         for (i = 0; i <= FL_HASH_MASK; i++) {
 176                 struct ip6_flowlabel *fl;
 177                 struct ip6_flowlabel __rcu **flp;
 178
 179                 flp = &fl_ht[i];
 180                 while ((fl = rcu_dereference_protected(*flp,
 181                                                        lockdep_is_held(&ip6_fl_lock))) != NULL) {
 182                         if (net_eq(fl->fl_net, net) &&
 183                             atomic_read(&fl->users) == 0) {
 184                                 *flp = fl->next;
 185                                 fl_free(fl);
 186                                 atomic_dec(&fl_size);
 187                                 continue;
 188                         }
 189                         flp = &fl->next;
 190                 }
 191         }
 192         spin_unlock_bh(&ip6_fl_lock);
 193 }
 194
 195 static struct ip6_flowlabel *fl_intern(struct net *net,
 196                                        struct ip6_flowlabel *fl, __be32 label)
 197 {
 198         struct ip6_flowlabel *lfl;
 199
 200         fl->label = label & IPV6_FLOWLABEL_MASK;
 201
 202         spin_lock_bh(&ip6_fl_lock);
 203         if (label == 0) {
 204                 for (;;) {
 205                         fl->label = htonl(prandom_u32())&IPV6_FLOWLABEL_MASK;
 206                         if (fl->label) {
 207                                 lfl = __fl_lookup(net, fl->label);
 208                                 if (!lfl)
 209                                         break;
 210                         }
 211                 }
 212         } else {
 213                 /*
 214                  * we dropper the ip6_fl_lock, so this entry could reappear
 215                  * and we need to recheck with it.
 216                  *
 217                  * OTOH no need to search the active socket first, like it is
 218                  * done in ipv6_flowlabel_opt - sock is locked, so new entry
 219                  * with the same label can only appear on another sock
 220                  */
 221                 lfl = __fl_lookup(net, fl->label);
 222                 if (lfl) {
 223                         atomic_inc(&lfl->users);
 224                         spin_unlock_bh(&ip6_fl_lock);
 225                         return lfl;
 226                 }
 227         }
 228
 229         fl->lastuse = jiffies;
 230         fl->next = fl_ht[FL_HASH(fl->label)];
 231         rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
 232         atomic_inc(&fl_size);
 233         spin_unlock_bh(&ip6_fl_lock);
 234         return NULL;
 235 }
 236
 237
 238
 239 /* Socket flowlabel lists */
 240
 241 struct ip6_flowlabel *fl6_sock_lookup(struct sock *sk, __be32 label)
 242 {
 243         struct ipv6_fl_socklist *sfl;
 244         struct ipv6_pinfo *np = inet6_sk(sk);
 245
 246         label &= IPV6_FLOWLABEL_MASK;
 247
 248         rcu_read_lock_bh();
 249         for_each_sk_fl_rcu(np, sfl) {
 250                 struct ip6_flowlabel *fl = sfl->fl;
 251                 if (fl->label == label) {
 252                         fl->lastuse = jiffies;
 253                         atomic_inc(&fl->users);
 254                         rcu_read_unlock_bh();
 255                         return fl;
 256                 }
 257         }
 258         rcu_read_unlock_bh();
 259         return NULL;
 260 }
 261 EXPORT_SYMBOL_GPL(fl6_sock_lookup);
 262
 263 void fl6_free_socklist(struct sock *sk)
 264 {
 265         struct ipv6_pinfo *np = inet6_sk(sk);
 266         struct ipv6_fl_socklist *sfl;
 267
 268         if (!rcu_access_pointer(np->ipv6_fl_list))
 269                 return;
 270
 271         spin_lock_bh(&ip6_sk_fl_lock);
 272         while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
 273                                                 lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
 274                 np->ipv6_fl_list = sfl->next;
 275                 spin_unlock_bh(&ip6_sk_fl_lock);
 276
 277                 fl_release(sfl->fl);
 278                 kfree_rcu(sfl, rcu);
 279
 280                 spin_lock_bh(&ip6_sk_fl_lock);
 281         }
 282         spin_unlock_bh(&ip6_sk_fl_lock);
 283 }
 284
 285 /* Service routines */
 286
 287
 288 /*
 289    It is the only difficult place. flowlabel enforces equal headers
 290    before and including routing header, however user may supply options
 291    following rthdr.
 292  */
 293
 294 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
 295                                          struct ip6_flowlabel *fl,
 296                                          struct ipv6_txoptions *fopt)
 297 {
 298         struct ipv6_txoptions *fl_opt = fl->opt;
 299
 300         if (!fopt || fopt->opt_flen == 0)
 301                 return fl_opt;
 302
 303         if (fl_opt) {
 304                 opt_space->hopopt = fl_opt->hopopt;
 305                 opt_space->dst0opt = fl_opt->dst0opt;
 306                 opt_space->srcrt = fl_opt->srcrt;
 307                 opt_space->opt_nflen = fl_opt->opt_nflen;
 308         } else {
 309                 if (fopt->opt_nflen == 0)
 310                         return fopt;
 311                 opt_space->hopopt = NULL;
 312                 opt_space->dst0opt = NULL;
 313                 opt_space->srcrt = NULL;
 314                 opt_space->opt_nflen = 0;
 315         }
 316         opt_space->dst1opt = fopt->dst1opt;
 317         opt_space->opt_flen = fopt->opt_flen;
 318         return opt_space;
 319 }
 320 EXPORT_SYMBOL_GPL(fl6_merge_options);
 321
 322 static unsigned long check_linger(unsigned long ttl)
 323 {
 324         if (ttl < FL_MIN_LINGER)
 325                 return FL_MIN_LINGER*HZ;
 326         if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
 327                 return 0;
 328         return ttl*HZ;
 329 }
 330
 331 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
 332 {
 333         linger = check_linger(linger);
 334         if (!linger)
 335                 return -EPERM;
 336         expires = check_linger(expires);
 337         if (!expires)
 338                 return -EPERM;
 339
 340         spin_lock_bh(&ip6_fl_lock);
 341         fl->lastuse = jiffies;
 342         if (time_before(fl->linger, linger))
 343                 fl->linger = linger;
 344         if (time_before(expires, fl->linger))
 345                 expires = fl->linger;
 346         if (time_before(fl->expires, fl->lastuse + expires))
 347                 fl->expires = fl->lastuse + expires;
 348         spin_unlock_bh(&ip6_fl_lock);
 349
 350         return 0;
 351 }
 352
 353 static struct ip6_flowlabel *
 354 fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 355           char __user *optval, int optlen, int *err_p)
 356 {
 357         struct ip6_flowlabel *fl = NULL;
 358         int olen;
 359         int addr_type;
 360         int err;
 361
 362         olen = optlen - CMSG_ALIGN(sizeof(*freq));
 363         err = -EINVAL;
 364         if (olen > 64 * 1024)
 365                 goto done;
 366
 367         err = -ENOMEM;
 368         fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 369         if (!fl)
 370                 goto done;
 371
 372         if (olen > 0) {
 373                 struct msghdr msg;
 374                 struct flowi6 flowi6;
 375                 struct sockcm_cookie sockc_junk;
 376                 struct ipcm6_cookie ipc6;
 377
 378                 err = -ENOMEM;
 379                 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 380                 if (!fl->opt)
 381                         goto done;
 382
 383                 memset(fl->opt, 0, sizeof(*fl->opt));
 384                 fl->opt->tot_len = sizeof(*fl->opt) + olen;
 385                 err = -EFAULT;
 386                 if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
 387                         goto done;
 388
 389                 msg.msg_controllen = olen;
 390                 msg.msg_control = (void *)(fl->opt+1);
 391                 memset(&flowi6, 0, sizeof(flowi6));
 392
 393                 ipc6.opt = fl->opt;
 394                 err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6, &sockc_junk);
 395                 if (err)
 396                         goto done;
 397                 err = -EINVAL;
 398                 if (fl->opt->opt_flen)
 399                         goto done;
 400                 if (fl->opt->opt_nflen == 0) {
 401                         kfree(fl->opt);
 402                         fl->opt = NULL;
 403                 }
 404         }
 405
 406         fl->fl_net = net;
 407         fl->expires = jiffies;
 408         err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 409         if (err)
 410                 goto done;
 411         fl->share = freq->flr_share;
 412         addr_type = ipv6_addr_type(&freq->flr_dst);
 413         if ((addr_type & IPV6_ADDR_MAPPED) ||
 414             addr_type == IPV6_ADDR_ANY) {
 415                 err = -EINVAL;
 416                 goto done;
 417         }
 418         fl->dst = freq->flr_dst;
 419         atomic_set(&fl->users, 1);
 420         switch (fl->share) {
 421         case IPV6_FL_S_EXCL:
 422         case IPV6_FL_S_ANY:
 423                 break;
 424         case IPV6_FL_S_PROCESS:
 425                 fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 426                 break;
 427         case IPV6_FL_S_USER:
 428                 fl->owner.uid = current_euid();
 429                 break;
 430         default:
 431                 err = -EINVAL;
 432                 goto done;
 433         }
 434         return fl;
 435
 436 done:
 437         fl_free(fl);
 438         *err_p = err;
 439         return NULL;
 440 }
 441
 442 static int mem_check(struct sock *sk)
 443 {
 444         struct ipv6_pinfo *np = inet6_sk(sk);
 445         struct ipv6_fl_socklist *sfl;
 446         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 447         int count = 0;
 448
 449         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 450                 return 0;
 451
 452         rcu_read_lock_bh();
 453         for_each_sk_fl_rcu(np, sfl)
 454                 count++;
 455         rcu_read_unlock_bh();
 456
 457         if (room <= 0 ||
 458             ((count >= FL_MAX_PER_SOCK ||
 459               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 460              !capable(CAP_NET_ADMIN)))
 461                 return -ENOBUFS;
 462
 463         return 0;
 464 }
 465
 466 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 467                 struct ip6_flowlabel *fl)
 468 {
 469         spin_lock_bh(&ip6_sk_fl_lock);
 470         sfl->fl = fl;
 471         sfl->next = np->ipv6_fl_list;
 472         rcu_assign_pointer(np->ipv6_fl_list, sfl);
 473         spin_unlock_bh(&ip6_sk_fl_lock);
 474 }
 475
 476 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 477                            int flags)
 478 {
 479         struct ipv6_pinfo *np = inet6_sk(sk);
 480         struct ipv6_fl_socklist *sfl;
 481
 482         if (flags & IPV6_FL_F_REMOTE) {
 483                 freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 484                 return 0;
 485         }
 486
 487         if (np->repflow) {
 488                 freq->flr_label = np->flow_label;
 489                 return 0;
 490         }
 491
 492         rcu_read_lock_bh();
 493
 494         for_each_sk_fl_rcu(np, sfl) {
 495                 if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 496                         spin_lock_bh(&ip6_fl_lock);
 497                         freq->flr_label = sfl->fl->label;
 498                         freq->flr_dst = sfl->fl->dst;
 499                         freq->flr_share = sfl->fl->share;
 500                         freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 501                         freq->flr_linger = sfl->fl->linger / HZ;
 502
 503                         spin_unlock_bh(&ip6_fl_lock);
 504                         rcu_read_unlock_bh();
 505                         return 0;
 506                 }
 507         }
 508         rcu_read_unlock_bh();
 509
 510         return -ENOENT;
 511 }
 512
 513 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 514 {
 515         int uninitialized_var(err);
 516         struct net *net = sock_net(sk);
 517         struct ipv6_pinfo *np = inet6_sk(sk);
 518         struct in6_flowlabel_req freq;
 519         struct ipv6_fl_socklist *sfl1 = NULL;
 520         struct ipv6_fl_socklist *sfl;
 521         struct ipv6_fl_socklist __rcu **sflp;
 522         struct ip6_flowlabel *fl, *fl1 = NULL;
 523
 524
 525         if (optlen < sizeof(freq))
 526                 return -EINVAL;
 527
 528         if (copy_from_user(&freq, optval, sizeof(freq)))
 529                 return -EFAULT;
 530
 531         switch (freq.flr_action) {
 532         case IPV6_FL_A_PUT:
 533                 if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 534                         if (sk->sk_protocol != IPPROTO_TCP)
 535                                 return -ENOPROTOOPT;
 536                         if (!np->repflow)
 537                                 return -ESRCH;
 538                         np->flow_label = 0;
 539                         np->repflow = 0;
 540                         return 0;
 541                 }
 542                 spin_lock_bh(&ip6_sk_fl_lock);
 543                 for (sflp = &np->ipv6_fl_list;
 544                      (sfl = rcu_dereference_protected(*sflp,
 545                                                       lockdep_is_held(&ip6_sk_fl_lock))) != NULL;
 546                      sflp = &sfl->next) {
 547                         if (sfl->fl->label == freq.flr_label) {
 548                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 549                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 550                                 *sflp = sfl->next;
 551                                 spin_unlock_bh(&ip6_sk_fl_lock);
 552                                 fl_release(sfl->fl);
 553                                 kfree_rcu(sfl, rcu);
 554                                 return 0;
 555                         }
 556                 }
 557                 spin_unlock_bh(&ip6_sk_fl_lock);
 558                 return -ESRCH;
 559
 560         case IPV6_FL_A_RENEW:
 561                 rcu_read_lock_bh();
 562                 for_each_sk_fl_rcu(np, sfl) {
 563                         if (sfl->fl->label == freq.flr_label) {
 564                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 565                                 rcu_read_unlock_bh();
 566                                 return err;
 567                         }
 568                 }
 569                 rcu_read_unlock_bh();
 570
 571                 if (freq.flr_share == IPV6_FL_S_NONE &&
 572                     ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 573                         fl = fl_lookup(net, freq.flr_label);
 574                         if (fl) {
 575                                 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 576                                 fl_release(fl);
 577                                 return err;
 578                         }
 579                 }
 580                 return -ESRCH;
 581
 582         case IPV6_FL_A_GET:
 583                 if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 584                         struct net *net = sock_net(sk);
 585                         if (net->ipv6.sysctl.flowlabel_consistency) {
 586                                 net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 587                                 return -EPERM;
 588                         }
 589
 590                         if (sk->sk_protocol != IPPROTO_TCP)
 591                                 return -ENOPROTOOPT;
 592
 593                         np->repflow = 1;
 594                         return 0;
 595                 }
 596
 597                 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 598                         return -EINVAL;
 599
 600                 if (net->ipv6.sysctl.flowlabel_state_ranges &&
 601                     (freq.flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 602                         return -ERANGE;
 603
 604                 fl = fl_create(net, sk, &freq, optval, optlen, &err);
 605                 if (!fl)
 606                         return err;
 607                 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 608
 609                 if (freq.flr_label) {
 610                         err = -EEXIST;
 611                         rcu_read_lock_bh();
 612                         for_each_sk_fl_rcu(np, sfl) {
 613                                 if (sfl->fl->label == freq.flr_label) {
 614                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
 615                                                 rcu_read_unlock_bh();
 616                                                 goto done;
 617                                         }
 618                                         fl1 = sfl->fl;
 619                                         atomic_inc(&fl1->users);
 620                                         break;
 621                                 }
 622                         }
 623                         rcu_read_unlock_bh();
 624
 625                         if (!fl1)
 626                                 fl1 = fl_lookup(net, freq.flr_label);
 627                         if (fl1) {
 628 recheck:
 629                                 err = -EEXIST;
 630                                 if (freq.flr_flags&IPV6_FL_F_EXCL)
 631                                         goto release;
 632                                 err = -EPERM;
 633                                 if (fl1->share == IPV6_FL_S_EXCL ||
 634                                     fl1->share != fl->share ||
 635                                     ((fl1->share == IPV6_FL_S_PROCESS) &&
 636                                      (fl1->owner.pid == fl->owner.pid)) ||
 637                                     ((fl1->share == IPV6_FL_S_USER) &&
 638                                      uid_eq(fl1->owner.uid, fl->owner.uid)))
 639                                         goto release;
 640
 641                                 err = -ENOMEM;
 642                                 if (!sfl1)
 643                                         goto release;
 644                                 if (fl->linger > fl1->linger)
 645                                         fl1->linger = fl->linger;
 646                                 if ((long)(fl->expires - fl1->expires) > 0)
 647                                         fl1->expires = fl->expires;
 648                                 fl_link(np, sfl1, fl1);
 649                                 fl_free(fl);
 650                                 return 0;
 651
 652 release:
 653                                 fl_release(fl1);
 654                                 goto done;
 655                         }
 656                 }
 657                 err = -ENOENT;
 658                 if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 659                         goto done;
 660
 661                 err = -ENOMEM;
 662                 if (!sfl1)
 663                         goto done;
 664
 665                 err = mem_check(sk);
 666                 if (err != 0)
 667                         goto done;
 668
 669                 fl1 = fl_intern(net, fl, freq.flr_label);
 670                 if (fl1)
 671                         goto recheck;
 672
 673                 if (!freq.flr_label) {
 674                         if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 675                                          &fl->label, sizeof(fl->label))) {
 676                                 /* Intentionally ignore fault. */
 677                         }
 678                 }
 679
 680                 fl_link(np, sfl1, fl);
 681                 return 0;
 682
 683         default:
 684                 return -EINVAL;
 685         }
 686
 687 done:
 688         fl_free(fl);
 689         kfree(sfl1);
 690         return err;
 691 }
 692
 693 #ifdef CONFIG_PROC_FS
 694
 695 struct ip6fl_iter_state {
 696         struct seq_net_private p;
 697         struct pid_namespace *pid_ns;
 698         int bucket;
 699 };
 700
 701 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 702
 703 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 704 {
 705         struct ip6_flowlabel *fl = NULL;
 706         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 707         struct net *net = seq_file_net(seq);
 708
 709         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 710                 for_each_fl_rcu(state->bucket, fl) {
 711                         if (net_eq(fl->fl_net, net))
 712                                 goto out;
 713                 }
 714         }
 715         fl = NULL;
 716 out:
 717         return fl;
 718 }
 719
 720 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 721 {
 722         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 723         struct net *net = seq_file_net(seq);
 724
 725         for_each_fl_continue_rcu(fl) {
 726                 if (net_eq(fl->fl_net, net))
 727                         goto out;
 728         }
 729
 730 try_again:
 731         if (++state->bucket <= FL_HASH_MASK) {
 732                 for_each_fl_rcu(state->bucket, fl) {
 733                         if (net_eq(fl->fl_net, net))
 734                                 goto out;
 735                 }
 736                 goto try_again;
 737         }
 738         fl = NULL;
 739
 740 out:
 741         return fl;
 742 }
 743
 744 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 745 {
 746         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 747         if (fl)
 748                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 749                         --pos;
 750         return pos ? NULL : fl;
 751 }
 752
 753 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 754         __acquires(RCU)
 755 {
 756         rcu_read_lock_bh();
 757         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 758 }
 759
 760 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 761 {
 762         struct ip6_flowlabel *fl;
 763
 764         if (v == SEQ_START_TOKEN)
 765                 fl = ip6fl_get_first(seq);
 766         else
 767                 fl = ip6fl_get_next(seq, v);
 768         ++*pos;
 769         return fl;
 770 }
 771
 772 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 773         __releases(RCU)
 774 {
 775         rcu_read_unlock_bh();
 776 }
 777
 778 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 779 {
 780         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 781         if (v == SEQ_START_TOKEN) {
 782                 seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
 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 }