linux/net/ipv6/ip6_flowlabel.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      ip6_flowlabel.c         IPv6 flowlabel manager.
   4 *
   5 *      Authors:        Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6 */
   7
   8#include <linux/capability.h>
   9#include <linux/errno.h>
  10#include <linux/types.h>
  11#include <linux/socket.h>
  12#include <linux/net.h>
  13#include <linux/netdevice.h>
  14#include <linux/in6.h>
  15#include <linux/proc_fs.h>
  16#include <linux/seq_file.h>
  17#include <linux/slab.h>
  18#include <linux/export.h>
  19#include <linux/pid_namespace.h>
  20#include <linux/jump_label_ratelimit.h>
  21
  22#include <net/net_namespace.h>
  23#include <net/sock.h>
  24
  25#include <net/ipv6.h>
  26#include <net/rawv6.h>
  27#include <net/transp_v6.h>
  28
  29#include <linux/uaccess.h>
  30
  31#define FL_MIN_LINGER   6       /* Minimal linger. It is set to 6sec specified
  32                                   in old IPv6 RFC. Well, it was reasonable value.
  33                                 */
  34#define FL_MAX_LINGER   150     /* Maximal linger timeout */
  35
  36/* FL hash table */
  37
  38#define FL_MAX_PER_SOCK 32
  39#define FL_MAX_SIZE     4096
  40#define FL_HASH_MASK    255
  41#define FL_HASH(l)      (ntohl(l)&FL_HASH_MASK)
  42
  43static atomic_t fl_size = ATOMIC_INIT(0);
  44static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
  45
  46static void ip6_fl_gc(struct timer_list *unused);
  47static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc);
  48
  49/* FL hash table lock: it protects only of GC */
  50
  51static DEFINE_SPINLOCK(ip6_fl_lock);
  52
  53/* Big socket sock */
  54
  55static DEFINE_SPINLOCK(ip6_sk_fl_lock);
  56
  57DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
  58EXPORT_SYMBOL(ipv6_flowlabel_exclusive);
  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
  74static 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
  85static 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
  97static bool fl_shared_exclusive(struct ip6_flowlabel *fl)
  98{
  99        return fl->share == IPV6_FL_S_EXCL ||
 100               fl->share == IPV6_FL_S_PROCESS ||
 101               fl->share == IPV6_FL_S_USER;
 102}
 103
 104static void fl_free_rcu(struct rcu_head *head)
 105{
 106        struct ip6_flowlabel *fl = container_of(head, struct ip6_flowlabel, rcu);
 107
 108        if (fl->share == IPV6_FL_S_PROCESS)
 109                put_pid(fl->owner.pid);
 110        kfree(fl->opt);
 111        kfree(fl);
 112}
 113
 114
 115static void fl_free(struct ip6_flowlabel *fl)
 116{
 117        if (!fl)
 118                return;
 119
 120        if (fl_shared_exclusive(fl) || fl->opt)
 121                static_branch_slow_dec_deferred(&ipv6_flowlabel_exclusive);
 122
 123        call_rcu(&fl->rcu, fl_free_rcu);
 124}
 125
 126static void fl_release(struct ip6_flowlabel *fl)
 127{
 128        spin_lock_bh(&ip6_fl_lock);
 129
 130        fl->lastuse = jiffies;
 131        if (atomic_dec_and_test(&fl->users)) {
 132                unsigned long ttd = fl->lastuse + fl->linger;
 133                if (time_after(ttd, fl->expires))
 134                        fl->expires = ttd;
 135                ttd = fl->expires;
 136                if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
 137                        struct ipv6_txoptions *opt = fl->opt;
 138                        fl->opt = NULL;
 139                        kfree(opt);
 140                }
 141                if (!timer_pending(&ip6_fl_gc_timer) ||
 142                    time_after(ip6_fl_gc_timer.expires, ttd))
 143                        mod_timer(&ip6_fl_gc_timer, ttd);
 144        }
 145        spin_unlock_bh(&ip6_fl_lock);
 146}
 147
 148static void ip6_fl_gc(struct timer_list *unused)
 149{
 150        int i;
 151        unsigned long now = jiffies;
 152        unsigned long sched = 0;
 153
 154        spin_lock(&ip6_fl_lock);
 155
 156        for (i = 0; i <= FL_HASH_MASK; i++) {
 157                struct ip6_flowlabel *fl;
 158                struct ip6_flowlabel __rcu **flp;
 159
 160                flp = &fl_ht[i];
 161                while ((fl = rcu_dereference_protected(*flp,
 162                                                       lockdep_is_held(&ip6_fl_lock))) != NULL) {
 163                        if (atomic_read(&fl->users) == 0) {
 164                                unsigned long ttd = fl->lastuse + fl->linger;
 165                                if (time_after(ttd, fl->expires))
 166                                        fl->expires = ttd;
 167                                ttd = fl->expires;
 168                                if (time_after_eq(now, ttd)) {
 169                                        *flp = fl->next;
 170                                        fl_free(fl);
 171                                        atomic_dec(&fl_size);
 172                                        continue;
 173                                }
 174                                if (!sched || time_before(ttd, sched))
 175                                        sched = ttd;
 176                        }
 177                        flp = &fl->next;
 178                }
 179        }
 180        if (!sched && atomic_read(&fl_size))
 181                sched = now + FL_MAX_LINGER;
 182        if (sched) {
 183                mod_timer(&ip6_fl_gc_timer, sched);
 184        }
 185        spin_unlock(&ip6_fl_lock);
 186}
 187
 188static void __net_exit ip6_fl_purge(struct net *net)
 189{
 190        int i;
 191
 192        spin_lock_bh(&ip6_fl_lock);
 193        for (i = 0; i <= FL_HASH_MASK; i++) {
 194                struct ip6_flowlabel *fl;
 195                struct ip6_flowlabel __rcu **flp;
 196
 197                flp = &fl_ht[i];
 198                while ((fl = rcu_dereference_protected(*flp,
 199                                                       lockdep_is_held(&ip6_fl_lock))) != NULL) {
 200                        if (net_eq(fl->fl_net, net) &&
 201                            atomic_read(&fl->users) == 0) {
 202                                *flp = fl->next;
 203                                fl_free(fl);
 204                                atomic_dec(&fl_size);
 205                                continue;
 206                        }
 207                        flp = &fl->next;
 208                }
 209        }
 210        spin_unlock_bh(&ip6_fl_lock);
 211}
 212
 213static struct ip6_flowlabel *fl_intern(struct net *net,
 214                                       struct ip6_flowlabel *fl, __be32 label)
 215{
 216        struct ip6_flowlabel *lfl;
 217
 218        fl->label = label & IPV6_FLOWLABEL_MASK;
 219
 220        spin_lock_bh(&ip6_fl_lock);
 221        if (label == 0) {
 222                for (;;) {
 223                        fl->label = htonl(prandom_u32())&IPV6_FLOWLABEL_MASK;
 224                        if (fl->label) {
 225                                lfl = __fl_lookup(net, fl->label);
 226                                if (!lfl)
 227                                        break;
 228                        }
 229                }
 230        } else {
 231                /*
 232                 * we dropper the ip6_fl_lock, so this entry could reappear
 233                 * and we need to recheck with it.
 234                 *
 235                 * OTOH no need to search the active socket first, like it is
 236                 * done in ipv6_flowlabel_opt - sock is locked, so new entry
 237                 * with the same label can only appear on another sock
 238                 */
 239                lfl = __fl_lookup(net, fl->label);
 240                if (lfl) {
 241                        atomic_inc(&lfl->users);
 242                        spin_unlock_bh(&ip6_fl_lock);
 243                        return lfl;
 244                }
 245        }
 246
 247        fl->lastuse = jiffies;
 248        fl->next = fl_ht[FL_HASH(fl->label)];
 249        rcu_assign_pointer(fl_ht[FL_HASH(fl->label)], fl);
 250        atomic_inc(&fl_size);
 251        spin_unlock_bh(&ip6_fl_lock);
 252        return NULL;
 253}
 254
 255
 256
 257/* Socket flowlabel lists */
 258
 259struct ip6_flowlabel *__fl6_sock_lookup(struct sock *sk, __be32 label)
 260{
 261        struct ipv6_fl_socklist *sfl;
 262        struct ipv6_pinfo *np = inet6_sk(sk);
 263
 264        label &= IPV6_FLOWLABEL_MASK;
 265
 266        rcu_read_lock_bh();
 267        for_each_sk_fl_rcu(np, sfl) {
 268                struct ip6_flowlabel *fl = sfl->fl;
 269
 270                if (fl->label == label && atomic_inc_not_zero(&fl->users)) {
 271                        fl->lastuse = jiffies;
 272                        rcu_read_unlock_bh();
 273                        return fl;
 274                }
 275        }
 276        rcu_read_unlock_bh();
 277        return NULL;
 278}
 279EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
 280
 281void fl6_free_socklist(struct sock *sk)
 282{
 283        struct ipv6_pinfo *np = inet6_sk(sk);
 284        struct ipv6_fl_socklist *sfl;
 285
 286        if (!rcu_access_pointer(np->ipv6_fl_list))
 287                return;
 288
 289        spin_lock_bh(&ip6_sk_fl_lock);
 290        while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
 291                                                lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
 292                np->ipv6_fl_list = sfl->next;
 293                spin_unlock_bh(&ip6_sk_fl_lock);
 294
 295                fl_release(sfl->fl);
 296                kfree_rcu(sfl, rcu);
 297
 298                spin_lock_bh(&ip6_sk_fl_lock);
 299        }
 300        spin_unlock_bh(&ip6_sk_fl_lock);
 301}
 302
 303/* Service routines */
 304
 305
 306/*
 307   It is the only difficult place. flowlabel enforces equal headers
 308   before and including routing header, however user may supply options
 309   following rthdr.
 310 */
 311
 312struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space,
 313                                         struct ip6_flowlabel *fl,
 314                                         struct ipv6_txoptions *fopt)
 315{
 316        struct ipv6_txoptions *fl_opt = fl->opt;
 317
 318        if (!fopt || fopt->opt_flen == 0)
 319                return fl_opt;
 320
 321        if (fl_opt) {
 322                opt_space->hopopt = fl_opt->hopopt;
 323                opt_space->dst0opt = fl_opt->dst0opt;
 324                opt_space->srcrt = fl_opt->srcrt;
 325                opt_space->opt_nflen = fl_opt->opt_nflen;
 326        } else {
 327                if (fopt->opt_nflen == 0)
 328                        return fopt;
 329                opt_space->hopopt = NULL;
 330                opt_space->dst0opt = NULL;
 331                opt_space->srcrt = NULL;
 332                opt_space->opt_nflen = 0;
 333        }
 334        opt_space->dst1opt = fopt->dst1opt;
 335        opt_space->opt_flen = fopt->opt_flen;
 336        opt_space->tot_len = fopt->tot_len;
 337        return opt_space;
 338}
 339EXPORT_SYMBOL_GPL(fl6_merge_options);
 340
 341static unsigned long check_linger(unsigned long ttl)
 342{
 343        if (ttl < FL_MIN_LINGER)
 344                return FL_MIN_LINGER*HZ;
 345        if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN))
 346                return 0;
 347        return ttl*HZ;
 348}
 349
 350static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires)
 351{
 352        linger = check_linger(linger);
 353        if (!linger)
 354                return -EPERM;
 355        expires = check_linger(expires);
 356        if (!expires)
 357                return -EPERM;
 358
 359        spin_lock_bh(&ip6_fl_lock);
 360        fl->lastuse = jiffies;
 361        if (time_before(fl->linger, linger))
 362                fl->linger = linger;
 363        if (time_before(expires, fl->linger))
 364                expires = fl->linger;
 365        if (time_before(fl->expires, fl->lastuse + expires))
 366                fl->expires = fl->lastuse + expires;
 367        spin_unlock_bh(&ip6_fl_lock);
 368
 369        return 0;
 370}
 371
 372static struct ip6_flowlabel *
 373fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq,
 374          char __user *optval, int optlen, int *err_p)
 375{
 376        struct ip6_flowlabel *fl = NULL;
 377        int olen;
 378        int addr_type;
 379        int err;
 380
 381        olen = optlen - CMSG_ALIGN(sizeof(*freq));
 382        err = -EINVAL;
 383        if (olen > 64 * 1024)
 384                goto done;
 385
 386        err = -ENOMEM;
 387        fl = kzalloc(sizeof(*fl), GFP_KERNEL);
 388        if (!fl)
 389                goto done;
 390
 391        if (olen > 0) {
 392                struct msghdr msg;
 393                struct flowi6 flowi6;
 394                struct ipcm6_cookie ipc6;
 395
 396                err = -ENOMEM;
 397                fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL);
 398                if (!fl->opt)
 399                        goto done;
 400
 401                memset(fl->opt, 0, sizeof(*fl->opt));
 402                fl->opt->tot_len = sizeof(*fl->opt) + olen;
 403                err = -EFAULT;
 404                if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen))
 405                        goto done;
 406
 407                msg.msg_controllen = olen;
 408                msg.msg_control = (void *)(fl->opt+1);
 409                memset(&flowi6, 0, sizeof(flowi6));
 410
 411                ipc6.opt = fl->opt;
 412                err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6);
 413                if (err)
 414                        goto done;
 415                err = -EINVAL;
 416                if (fl->opt->opt_flen)
 417                        goto done;
 418                if (fl->opt->opt_nflen == 0) {
 419                        kfree(fl->opt);
 420                        fl->opt = NULL;
 421                }
 422        }
 423
 424        fl->fl_net = net;
 425        fl->expires = jiffies;
 426        err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 427        if (err)
 428                goto done;
 429        fl->share = freq->flr_share;
 430        addr_type = ipv6_addr_type(&freq->flr_dst);
 431        if ((addr_type & IPV6_ADDR_MAPPED) ||
 432            addr_type == IPV6_ADDR_ANY) {
 433                err = -EINVAL;
 434                goto done;
 435        }
 436        fl->dst = freq->flr_dst;
 437        atomic_set(&fl->users, 1);
 438        switch (fl->share) {
 439        case IPV6_FL_S_EXCL:
 440        case IPV6_FL_S_ANY:
 441                break;
 442        case IPV6_FL_S_PROCESS:
 443                fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 444                break;
 445        case IPV6_FL_S_USER:
 446                fl->owner.uid = current_euid();
 447                break;
 448        default:
 449                err = -EINVAL;
 450                goto done;
 451        }
 452        if (fl_shared_exclusive(fl) || fl->opt)
 453                static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
 454        return fl;
 455
 456done:
 457        if (fl) {
 458                kfree(fl->opt);
 459                kfree(fl);
 460        }
 461        *err_p = err;
 462        return NULL;
 463}
 464
 465static int mem_check(struct sock *sk)
 466{
 467        struct ipv6_pinfo *np = inet6_sk(sk);
 468        struct ipv6_fl_socklist *sfl;
 469        int room = FL_MAX_SIZE - atomic_read(&fl_size);
 470        int count = 0;
 471
 472        if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 473                return 0;
 474
 475        rcu_read_lock_bh();
 476        for_each_sk_fl_rcu(np, sfl)
 477                count++;
 478        rcu_read_unlock_bh();
 479
 480        if (room <= 0 ||
 481            ((count >= FL_MAX_PER_SOCK ||
 482              (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 483             !capable(CAP_NET_ADMIN)))
 484                return -ENOBUFS;
 485
 486        return 0;
 487}
 488
 489static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 490                struct ip6_flowlabel *fl)
 491{
 492        spin_lock_bh(&ip6_sk_fl_lock);
 493        sfl->fl = fl;
 494        sfl->next = np->ipv6_fl_list;
 495        rcu_assign_pointer(np->ipv6_fl_list, sfl);
 496        spin_unlock_bh(&ip6_sk_fl_lock);
 497}
 498
 499int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 500                           int flags)
 501{
 502        struct ipv6_pinfo *np = inet6_sk(sk);
 503        struct ipv6_fl_socklist *sfl;
 504
 505        if (flags & IPV6_FL_F_REMOTE) {
 506                freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 507                return 0;
 508        }
 509
 510        if (np->repflow) {
 511                freq->flr_label = np->flow_label;
 512                return 0;
 513        }
 514
 515        rcu_read_lock_bh();
 516
 517        for_each_sk_fl_rcu(np, sfl) {
 518                if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 519                        spin_lock_bh(&ip6_fl_lock);
 520                        freq->flr_label = sfl->fl->label;
 521                        freq->flr_dst = sfl->fl->dst;
 522                        freq->flr_share = sfl->fl->share;
 523                        freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 524                        freq->flr_linger = sfl->fl->linger / HZ;
 525
 526                        spin_unlock_bh(&ip6_fl_lock);
 527                        rcu_read_unlock_bh();
 528                        return 0;
 529                }
 530        }
 531        rcu_read_unlock_bh();
 532
 533        return -ENOENT;
 534}
 535
 536int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 537{
 538        int uninitialized_var(err);
 539        struct net *net = sock_net(sk);
 540        struct ipv6_pinfo *np = inet6_sk(sk);
 541        struct in6_flowlabel_req freq;
 542        struct ipv6_fl_socklist *sfl1 = NULL;
 543        struct ipv6_fl_socklist *sfl;
 544        struct ipv6_fl_socklist __rcu **sflp;
 545        struct ip6_flowlabel *fl, *fl1 = NULL;
 546
 547
 548        if (optlen < sizeof(freq))
 549                return -EINVAL;
 550
 551        if (copy_from_user(&freq, optval, sizeof(freq)))
 552                return -EFAULT;
 553
 554        switch (freq.flr_action) {
 555        case IPV6_FL_A_PUT:
 556                if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 557                        if (sk->sk_protocol != IPPROTO_TCP)
 558                                return -ENOPROTOOPT;
 559                        if (!np->repflow)
 560                                return -ESRCH;
 561                        np->flow_label = 0;
 562                        np->repflow = 0;
 563                        return 0;
 564                }
 565                spin_lock_bh(&ip6_sk_fl_lock);
 566                for (sflp = &np->ipv6_fl_list;
 567                     (sfl = rcu_dereference_protected(*sflp,
 568                                                      lockdep_is_held(&ip6_sk_fl_lock))) != NULL;
 569                     sflp = &sfl->next) {
 570                        if (sfl->fl->label == freq.flr_label) {
 571                                if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
 572                                        np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 573                                *sflp = sfl->next;
 574                                spin_unlock_bh(&ip6_sk_fl_lock);
 575                                fl_release(sfl->fl);
 576                                kfree_rcu(sfl, rcu);
 577                                return 0;
 578                        }
 579                }
 580                spin_unlock_bh(&ip6_sk_fl_lock);
 581                return -ESRCH;
 582
 583        case IPV6_FL_A_RENEW:
 584                rcu_read_lock_bh();
 585                for_each_sk_fl_rcu(np, sfl) {
 586                        if (sfl->fl->label == freq.flr_label) {
 587                                err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
 588                                rcu_read_unlock_bh();
 589                                return err;
 590                        }
 591                }
 592                rcu_read_unlock_bh();
 593
 594                if (freq.flr_share == IPV6_FL_S_NONE &&
 595                    ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 596                        fl = fl_lookup(net, freq.flr_label);
 597                        if (fl) {
 598                                err = fl6_renew(fl, freq.flr_linger, freq.flr_expires);
 599                                fl_release(fl);
 600                                return err;
 601                        }
 602                }
 603                return -ESRCH;
 604
 605        case IPV6_FL_A_GET:
 606                if (freq.flr_flags & IPV6_FL_F_REFLECT) {
 607                        struct net *net = sock_net(sk);
 608                        if (net->ipv6.sysctl.flowlabel_consistency) {
 609                                net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 610                                return -EPERM;
 611                        }
 612
 613                        if (sk->sk_protocol != IPPROTO_TCP)
 614                                return -ENOPROTOOPT;
 615
 616                        np->repflow = 1;
 617                        return 0;
 618                }
 619
 620                if (freq.flr_label & ~IPV6_FLOWLABEL_MASK)
 621                        return -EINVAL;
 622
 623                if (net->ipv6.sysctl.flowlabel_state_ranges &&
 624                    (freq.flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 625                        return -ERANGE;
 626
 627                fl = fl_create(net, sk, &freq, optval, optlen, &err);
 628                if (!fl)
 629                        return err;
 630                sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 631
 632                if (freq.flr_label) {
 633                        err = -EEXIST;
 634                        rcu_read_lock_bh();
 635                        for_each_sk_fl_rcu(np, sfl) {
 636                                if (sfl->fl->label == freq.flr_label) {
 637                                        if (freq.flr_flags&IPV6_FL_F_EXCL) {
 638                                                rcu_read_unlock_bh();
 639                                                goto done;
 640                                        }
 641                                        fl1 = sfl->fl;
 642                                        if (!atomic_inc_not_zero(&fl1->users))
 643                                                fl1 = NULL;
 644                                        break;
 645                                }
 646                        }
 647                        rcu_read_unlock_bh();
 648
 649                        if (!fl1)
 650                                fl1 = fl_lookup(net, freq.flr_label);
 651                        if (fl1) {
 652recheck:
 653                                err = -EEXIST;
 654                                if (freq.flr_flags&IPV6_FL_F_EXCL)
 655                                        goto release;
 656                                err = -EPERM;
 657                                if (fl1->share == IPV6_FL_S_EXCL ||
 658                                    fl1->share != fl->share ||
 659                                    ((fl1->share == IPV6_FL_S_PROCESS) &&
 660                                     (fl1->owner.pid != fl->owner.pid)) ||
 661                                    ((fl1->share == IPV6_FL_S_USER) &&
 662                                     !uid_eq(fl1->owner.uid, fl->owner.uid)))
 663                                        goto release;
 664
 665                                err = -ENOMEM;
 666                                if (!sfl1)
 667                                        goto release;
 668                                if (fl->linger > fl1->linger)
 669                                        fl1->linger = fl->linger;
 670                                if ((long)(fl->expires - fl1->expires) > 0)
 671                                        fl1->expires = fl->expires;
 672                                fl_link(np, sfl1, fl1);
 673                                fl_free(fl);
 674                                return 0;
 675
 676release:
 677                                fl_release(fl1);
 678                                goto done;
 679                        }
 680                }
 681                err = -ENOENT;
 682                if (!(freq.flr_flags&IPV6_FL_F_CREATE))
 683                        goto done;
 684
 685                err = -ENOMEM;
 686                if (!sfl1)
 687                        goto done;
 688
 689                err = mem_check(sk);
 690                if (err != 0)
 691                        goto done;
 692
 693                fl1 = fl_intern(net, fl, freq.flr_label);
 694                if (fl1)
 695                        goto recheck;
 696
 697                if (!freq.flr_label) {
 698                        if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label,
 699                                         &fl->label, sizeof(fl->label))) {
 700                                /* Intentionally ignore fault. */
 701                        }
 702                }
 703
 704                fl_link(np, sfl1, fl);
 705                return 0;
 706
 707        default:
 708                return -EINVAL;
 709        }
 710
 711done:
 712        fl_free(fl);
 713        kfree(sfl1);
 714        return err;
 715}
 716
 717#ifdef CONFIG_PROC_FS
 718
 719struct ip6fl_iter_state {
 720        struct seq_net_private p;
 721        struct pid_namespace *pid_ns;
 722        int bucket;
 723};
 724
 725#define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 726
 727static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 728{
 729        struct ip6_flowlabel *fl = NULL;
 730        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 731        struct net *net = seq_file_net(seq);
 732
 733        for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 734                for_each_fl_rcu(state->bucket, fl) {
 735                        if (net_eq(fl->fl_net, net))
 736                                goto out;
 737                }
 738        }
 739        fl = NULL;
 740out:
 741        return fl;
 742}
 743
 744static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 745{
 746        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 747        struct net *net = seq_file_net(seq);
 748
 749        for_each_fl_continue_rcu(fl) {
 750                if (net_eq(fl->fl_net, net))
 751                        goto out;
 752        }
 753
 754try_again:
 755        if (++state->bucket <= FL_HASH_MASK) {
 756                for_each_fl_rcu(state->bucket, fl) {
 757                        if (net_eq(fl->fl_net, net))
 758                                goto out;
 759                }
 760                goto try_again;
 761        }
 762        fl = NULL;
 763
 764out:
 765        return fl;
 766}
 767
 768static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 769{
 770        struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 771        if (fl)
 772                while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 773                        --pos;
 774        return pos ? NULL : fl;
 775}
 776
 777static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 778        __acquires(RCU)
 779{
 780        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 781
 782        state->pid_ns = proc_pid_ns(file_inode(seq->file));
 783
 784        rcu_read_lock_bh();
 785        return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 786}
 787
 788static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 789{
 790        struct ip6_flowlabel *fl;
 791
 792        if (v == SEQ_START_TOKEN)
 793                fl = ip6fl_get_first(seq);
 794        else
 795                fl = ip6fl_get_next(seq, v);
 796        ++*pos;
 797        return fl;
 798}
 799
 800static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 801        __releases(RCU)
 802{
 803        rcu_read_unlock_bh();
 804}
 805
 806static int ip6fl_seq_show(struct seq_file *seq, void *v)
 807{
 808        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 809        if (v == SEQ_START_TOKEN) {
 810                seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
 811        } else {
 812                struct ip6_flowlabel *fl = v;
 813                seq_printf(seq,
 814                           "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 815                           (unsigned int)ntohl(fl->label),
 816                           fl->share,
 817                           ((fl->share == IPV6_FL_S_PROCESS) ?
 818                            pid_nr_ns(fl->owner.pid, state->pid_ns) :
 819                            ((fl->share == IPV6_FL_S_USER) ?
 820                             from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 821                             0)),
 822                           atomic_read(&fl->users),
 823                           fl->linger/HZ,
 824                           (long)(fl->expires - jiffies)/HZ,
 825                           &fl->dst,
 826                           fl->opt ? fl->opt->opt_nflen : 0);
 827        }
 828        return 0;
 829}
 830
 831static const struct seq_operations ip6fl_seq_ops = {
 832        .start  =       ip6fl_seq_start,
 833        .next   =       ip6fl_seq_next,
 834        .stop   =       ip6fl_seq_stop,
 835        .show   =       ip6fl_seq_show,
 836};
 837
 838static int __net_init ip6_flowlabel_proc_init(struct net *net)
 839{
 840        if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
 841                        &ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))
 842                return -ENOMEM;
 843        return 0;
 844}
 845
 846static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 847{
 848        remove_proc_entry("ip6_flowlabel", net->proc_net);
 849}
 850#else
 851static inline int ip6_flowlabel_proc_init(struct net *net)
 852{
 853        return 0;
 854}
 855static inline void ip6_flowlabel_proc_fini(struct net *net)
 856{
 857}
 858#endif
 859
 860static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 861{
 862        ip6_fl_purge(net);
 863        ip6_flowlabel_proc_fini(net);
 864}
 865
 866static struct pernet_operations ip6_flowlabel_net_ops = {
 867        .init = ip6_flowlabel_proc_init,
 868        .exit = ip6_flowlabel_net_exit,
 869};
 870
 871int ip6_flowlabel_init(void)
 872{
 873        return register_pernet_subsys(&ip6_flowlabel_net_ops);
 874}
 875
 876void ip6_flowlabel_cleanup(void)
 877{
 878        static_key_deferred_flush(&ipv6_flowlabel_exclusive);
 879        del_timer(&ip6_fl_gc_timer);
 880        unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 881}
 882