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          sockptr_t 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_sockptr_offset(fl->opt + 1, optval,
 405                                CMSG_ALIGN(sizeof(*freq)), olen))
 406                        goto done;
 407
 408                msg.msg_controllen = olen;
 409                msg.msg_control = (void *)(fl->opt+1);
 410                memset(&flowi6, 0, sizeof(flowi6));
 411
 412                ipc6.opt = fl->opt;
 413                err = ip6_datagram_send_ctl(net, sk, &msg, &flowi6, &ipc6);
 414                if (err)
 415                        goto done;
 416                err = -EINVAL;
 417                if (fl->opt->opt_flen)
 418                        goto done;
 419                if (fl->opt->opt_nflen == 0) {
 420                        kfree(fl->opt);
 421                        fl->opt = NULL;
 422                }
 423        }
 424
 425        fl->fl_net = net;
 426        fl->expires = jiffies;
 427        err = fl6_renew(fl, freq->flr_linger, freq->flr_expires);
 428        if (err)
 429                goto done;
 430        fl->share = freq->flr_share;
 431        addr_type = ipv6_addr_type(&freq->flr_dst);
 432        if ((addr_type & IPV6_ADDR_MAPPED) ||
 433            addr_type == IPV6_ADDR_ANY) {
 434                err = -EINVAL;
 435                goto done;
 436        }
 437        fl->dst = freq->flr_dst;
 438        atomic_set(&fl->users, 1);
 439        switch (fl->share) {
 440        case IPV6_FL_S_EXCL:
 441        case IPV6_FL_S_ANY:
 442                break;
 443        case IPV6_FL_S_PROCESS:
 444                fl->owner.pid = get_task_pid(current, PIDTYPE_PID);
 445                break;
 446        case IPV6_FL_S_USER:
 447                fl->owner.uid = current_euid();
 448                break;
 449        default:
 450                err = -EINVAL;
 451                goto done;
 452        }
 453        if (fl_shared_exclusive(fl) || fl->opt)
 454                static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
 455        return fl;
 456
 457done:
 458        if (fl) {
 459                kfree(fl->opt);
 460                kfree(fl);
 461        }
 462        *err_p = err;
 463        return NULL;
 464}
 465
 466static int mem_check(struct sock *sk)
 467{
 468        struct ipv6_pinfo *np = inet6_sk(sk);
 469        struct ipv6_fl_socklist *sfl;
 470        int room = FL_MAX_SIZE - atomic_read(&fl_size);
 471        int count = 0;
 472
 473        if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 474                return 0;
 475
 476        rcu_read_lock_bh();
 477        for_each_sk_fl_rcu(np, sfl)
 478                count++;
 479        rcu_read_unlock_bh();
 480
 481        if (room <= 0 ||
 482            ((count >= FL_MAX_PER_SOCK ||
 483              (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 484             !capable(CAP_NET_ADMIN)))
 485                return -ENOBUFS;
 486
 487        return 0;
 488}
 489
 490static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 491                struct ip6_flowlabel *fl)
 492{
 493        spin_lock_bh(&ip6_sk_fl_lock);
 494        sfl->fl = fl;
 495        sfl->next = np->ipv6_fl_list;
 496        rcu_assign_pointer(np->ipv6_fl_list, sfl);
 497        spin_unlock_bh(&ip6_sk_fl_lock);
 498}
 499
 500int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 501                           int flags)
 502{
 503        struct ipv6_pinfo *np = inet6_sk(sk);
 504        struct ipv6_fl_socklist *sfl;
 505
 506        if (flags & IPV6_FL_F_REMOTE) {
 507                freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 508                return 0;
 509        }
 510
 511        if (np->repflow) {
 512                freq->flr_label = np->flow_label;
 513                return 0;
 514        }
 515
 516        rcu_read_lock_bh();
 517
 518        for_each_sk_fl_rcu(np, sfl) {
 519                if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 520                        spin_lock_bh(&ip6_fl_lock);
 521                        freq->flr_label = sfl->fl->label;
 522                        freq->flr_dst = sfl->fl->dst;
 523                        freq->flr_share = sfl->fl->share;
 524                        freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 525                        freq->flr_linger = sfl->fl->linger / HZ;
 526
 527                        spin_unlock_bh(&ip6_fl_lock);
 528                        rcu_read_unlock_bh();
 529                        return 0;
 530                }
 531        }
 532        rcu_read_unlock_bh();
 533
 534        return -ENOENT;
 535}
 536
 537#define socklist_dereference(__sflp) \
 538        rcu_dereference_protected(__sflp, lockdep_is_held(&ip6_sk_fl_lock))
 539
 540static int ipv6_flowlabel_put(struct sock *sk, struct in6_flowlabel_req *freq)
 541{
 542        struct ipv6_pinfo *np = inet6_sk(sk);
 543        struct ipv6_fl_socklist __rcu **sflp;
 544        struct ipv6_fl_socklist *sfl;
 545
 546        if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 547                if (sk->sk_protocol != IPPROTO_TCP)
 548                        return -ENOPROTOOPT;
 549                if (!np->repflow)
 550                        return -ESRCH;
 551                np->flow_label = 0;
 552                np->repflow = 0;
 553                return 0;
 554        }
 555
 556        spin_lock_bh(&ip6_sk_fl_lock);
 557        for (sflp = &np->ipv6_fl_list;
 558             (sfl = socklist_dereference(*sflp)) != NULL;
 559             sflp = &sfl->next) {
 560                if (sfl->fl->label == freq->flr_label)
 561                        goto found;
 562        }
 563        spin_unlock_bh(&ip6_sk_fl_lock);
 564        return -ESRCH;
 565found:
 566        if (freq->flr_label == (np->flow_label & IPV6_FLOWLABEL_MASK))
 567                np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 568        *sflp = sfl->next;
 569        spin_unlock_bh(&ip6_sk_fl_lock);
 570        fl_release(sfl->fl);
 571        kfree_rcu(sfl, rcu);
 572        return 0;
 573}
 574
 575static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
 576{
 577        struct ipv6_pinfo *np = inet6_sk(sk);
 578        struct net *net = sock_net(sk);
 579        struct ipv6_fl_socklist *sfl;
 580        int err;
 581
 582        rcu_read_lock_bh();
 583        for_each_sk_fl_rcu(np, sfl) {
 584                if (sfl->fl->label == freq->flr_label) {
 585                        err = fl6_renew(sfl->fl, freq->flr_linger,
 586                                        freq->flr_expires);
 587                        rcu_read_unlock_bh();
 588                        return err;
 589                }
 590        }
 591        rcu_read_unlock_bh();
 592
 593        if (freq->flr_share == IPV6_FL_S_NONE &&
 594            ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 595                struct ip6_flowlabel *fl = fl_lookup(net, freq->flr_label);
 596
 597                if (fl) {
 598                        err = fl6_renew(fl, freq->flr_linger,
 599                                        freq->flr_expires);
 600                        fl_release(fl);
 601                        return err;
 602                }
 603        }
 604        return -ESRCH;
 605}
 606
 607static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 608                sockptr_t optval, int optlen)
 609{
 610        struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
 611        struct ip6_flowlabel *fl, *fl1 = NULL;
 612        struct ipv6_pinfo *np = inet6_sk(sk);
 613        struct net *net = sock_net(sk);
 614        int err;
 615
 616        if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 617                if (net->ipv6.sysctl.flowlabel_consistency) {
 618                        net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 619                        return -EPERM;
 620                }
 621
 622                if (sk->sk_protocol != IPPROTO_TCP)
 623                        return -ENOPROTOOPT;
 624                np->repflow = 1;
 625                return 0;
 626        }
 627
 628        if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
 629                return -EINVAL;
 630        if (net->ipv6.sysctl.flowlabel_state_ranges &&
 631            (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 632                return -ERANGE;
 633
 634        fl = fl_create(net, sk, freq, optval, optlen, &err);
 635        if (!fl)
 636                return err;
 637
 638        sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 639
 640        if (freq->flr_label) {
 641                err = -EEXIST;
 642                rcu_read_lock_bh();
 643                for_each_sk_fl_rcu(np, sfl) {
 644                        if (sfl->fl->label == freq->flr_label) {
 645                                if (freq->flr_flags & IPV6_FL_F_EXCL) {
 646                                        rcu_read_unlock_bh();
 647                                        goto done;
 648                                }
 649                                fl1 = sfl->fl;
 650                                if (!atomic_inc_not_zero(&fl1->users))
 651                                        fl1 = NULL;
 652                                break;
 653                        }
 654                }
 655                rcu_read_unlock_bh();
 656
 657                if (!fl1)
 658                        fl1 = fl_lookup(net, freq->flr_label);
 659                if (fl1) {
 660recheck:
 661                        err = -EEXIST;
 662                        if (freq->flr_flags&IPV6_FL_F_EXCL)
 663                                goto release;
 664                        err = -EPERM;
 665                        if (fl1->share == IPV6_FL_S_EXCL ||
 666                            fl1->share != fl->share ||
 667                            ((fl1->share == IPV6_FL_S_PROCESS) &&
 668                             (fl1->owner.pid != fl->owner.pid)) ||
 669                            ((fl1->share == IPV6_FL_S_USER) &&
 670                             !uid_eq(fl1->owner.uid, fl->owner.uid)))
 671                                goto release;
 672
 673                        err = -ENOMEM;
 674                        if (!sfl1)
 675                                goto release;
 676                        if (fl->linger > fl1->linger)
 677                                fl1->linger = fl->linger;
 678                        if ((long)(fl->expires - fl1->expires) > 0)
 679                                fl1->expires = fl->expires;
 680                        fl_link(np, sfl1, fl1);
 681                        fl_free(fl);
 682                        return 0;
 683
 684release:
 685                        fl_release(fl1);
 686                        goto done;
 687                }
 688        }
 689        err = -ENOENT;
 690        if (!(freq->flr_flags & IPV6_FL_F_CREATE))
 691                goto done;
 692
 693        err = -ENOMEM;
 694        if (!sfl1)
 695                goto done;
 696
 697        err = mem_check(sk);
 698        if (err != 0)
 699                goto done;
 700
 701        fl1 = fl_intern(net, fl, freq->flr_label);
 702        if (fl1)
 703                goto recheck;
 704
 705        if (!freq->flr_label) {
 706                size_t offset = offsetof(struct in6_flowlabel_req, flr_label);
 707
 708                if (copy_to_sockptr_offset(optval, offset, &fl->label,
 709                                sizeof(fl->label))) {
 710                        /* Intentionally ignore fault. */
 711                }
 712        }
 713
 714        fl_link(np, sfl1, fl);
 715        return 0;
 716done:
 717        fl_free(fl);
 718        kfree(sfl1);
 719        return err;
 720}
 721
 722int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)
 723{
 724        struct in6_flowlabel_req freq;
 725
 726        if (optlen < sizeof(freq))
 727                return -EINVAL;
 728        if (copy_from_sockptr(&freq, optval, sizeof(freq)))
 729                return -EFAULT;
 730
 731        switch (freq.flr_action) {
 732        case IPV6_FL_A_PUT:
 733                return ipv6_flowlabel_put(sk, &freq);
 734        case IPV6_FL_A_RENEW:
 735                return ipv6_flowlabel_renew(sk, &freq);
 736        case IPV6_FL_A_GET:
 737                return ipv6_flowlabel_get(sk, &freq, optval, optlen);
 738        default:
 739                return -EINVAL;
 740        }
 741}
 742
 743#ifdef CONFIG_PROC_FS
 744
 745struct ip6fl_iter_state {
 746        struct seq_net_private p;
 747        struct pid_namespace *pid_ns;
 748        int bucket;
 749};
 750
 751#define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 752
 753static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 754{
 755        struct ip6_flowlabel *fl = NULL;
 756        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 757        struct net *net = seq_file_net(seq);
 758
 759        for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 760                for_each_fl_rcu(state->bucket, fl) {
 761                        if (net_eq(fl->fl_net, net))
 762                                goto out;
 763                }
 764        }
 765        fl = NULL;
 766out:
 767        return fl;
 768}
 769
 770static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 771{
 772        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 773        struct net *net = seq_file_net(seq);
 774
 775        for_each_fl_continue_rcu(fl) {
 776                if (net_eq(fl->fl_net, net))
 777                        goto out;
 778        }
 779
 780try_again:
 781        if (++state->bucket <= FL_HASH_MASK) {
 782                for_each_fl_rcu(state->bucket, fl) {
 783                        if (net_eq(fl->fl_net, net))
 784                                goto out;
 785                }
 786                goto try_again;
 787        }
 788        fl = NULL;
 789
 790out:
 791        return fl;
 792}
 793
 794static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 795{
 796        struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 797        if (fl)
 798                while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 799                        --pos;
 800        return pos ? NULL : fl;
 801}
 802
 803static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 804        __acquires(RCU)
 805{
 806        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 807
 808        state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
 809
 810        rcu_read_lock_bh();
 811        return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 812}
 813
 814static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 815{
 816        struct ip6_flowlabel *fl;
 817
 818        if (v == SEQ_START_TOKEN)
 819                fl = ip6fl_get_first(seq);
 820        else
 821                fl = ip6fl_get_next(seq, v);
 822        ++*pos;
 823        return fl;
 824}
 825
 826static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 827        __releases(RCU)
 828{
 829        rcu_read_unlock_bh();
 830}
 831
 832static int ip6fl_seq_show(struct seq_file *seq, void *v)
 833{
 834        struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 835        if (v == SEQ_START_TOKEN) {
 836                seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
 837        } else {
 838                struct ip6_flowlabel *fl = v;
 839                seq_printf(seq,
 840                           "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 841                           (unsigned int)ntohl(fl->label),
 842                           fl->share,
 843                           ((fl->share == IPV6_FL_S_PROCESS) ?
 844                            pid_nr_ns(fl->owner.pid, state->pid_ns) :
 845                            ((fl->share == IPV6_FL_S_USER) ?
 846                             from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 847                             0)),
 848                           atomic_read(&fl->users),
 849                           fl->linger/HZ,
 850                           (long)(fl->expires - jiffies)/HZ,
 851                           &fl->dst,
 852                           fl->opt ? fl->opt->opt_nflen : 0);
 853        }
 854        return 0;
 855}
 856
 857static const struct seq_operations ip6fl_seq_ops = {
 858        .start  =       ip6fl_seq_start,
 859        .next   =       ip6fl_seq_next,
 860        .stop   =       ip6fl_seq_stop,
 861        .show   =       ip6fl_seq_show,
 862};
 863
 864static int __net_init ip6_flowlabel_proc_init(struct net *net)
 865{
 866        if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
 867                        &ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))
 868                return -ENOMEM;
 869        return 0;
 870}
 871
 872static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 873{
 874        remove_proc_entry("ip6_flowlabel", net->proc_net);
 875}
 876#else
 877static inline int ip6_flowlabel_proc_init(struct net *net)
 878{
 879        return 0;
 880}
 881static inline void ip6_flowlabel_proc_fini(struct net *net)
 882{
 883}
 884#endif
 885
 886static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 887{
 888        ip6_fl_purge(net);
 889        ip6_flowlabel_proc_fini(net);
 890}
 891
 892static struct pernet_operations ip6_flowlabel_net_ops = {
 893        .init = ip6_flowlabel_proc_init,
 894        .exit = ip6_flowlabel_net_exit,
 895};
 896
 897int ip6_flowlabel_init(void)
 898{
 899        return register_pernet_subsys(&ip6_flowlabel_net_ops);
 900}
 901
 902void ip6_flowlabel_cleanup(void)
 903{
 904        static_key_deferred_flush(&ipv6_flowlabel_exclusive);
 905        del_timer(&ip6_fl_gc_timer);
 906        unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 907}
 908