net/ipv6/ip6_flowlabel.c

   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
  43 static atomic_t fl_size = ATOMIC_INIT(0);
  44 static struct ip6_flowlabel __rcu *fl_ht[FL_HASH_MASK+1];
  45
  46 static void ip6_fl_gc(struct timer_list *unused);
  47 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc);
  48
  49 /* FL hash table lock: it protects only of GC */
  50
  51 static DEFINE_SPINLOCK(ip6_fl_lock);
  52
  53 /* Big socket sock */
  54
  55 static DEFINE_SPINLOCK(ip6_sk_fl_lock);
  56
  57 DEFINE_STATIC_KEY_DEFERRED_FALSE(ipv6_flowlabel_exclusive, HZ);
  58 EXPORT_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
  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 static 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
 104 static 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
 115 static 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
 126 static 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
 148 static 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
 188 static 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
 213 static 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
 259 struct 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 }
 279 EXPORT_SYMBOL_GPL(__fl6_sock_lookup);
 280
 281 void 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
 312 struct 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 }
 339 EXPORT_SYMBOL_GPL(fl6_merge_options);
 340
 341 static 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
 350 static 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
 372 static struct ip6_flowlabel *
 373 fl_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                 WRITE_ONCE(sock_net(sk)->ipv6.flowlabel_has_excl, 1);
 455                 static_branch_deferred_inc(&ipv6_flowlabel_exclusive);
 456         }
 457         return fl;
 458
 459 done:
 460         if (fl) {
 461                 kfree(fl->opt);
 462                 kfree(fl);
 463         }
 464         *err_p = err;
 465         return NULL;
 466 }
 467
 468 static int mem_check(struct sock *sk)
 469 {
 470         struct ipv6_pinfo *np = inet6_sk(sk);
 471         struct ipv6_fl_socklist *sfl;
 472         int room = FL_MAX_SIZE - atomic_read(&fl_size);
 473         int count = 0;
 474
 475         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
 476                 return 0;
 477
 478         rcu_read_lock_bh();
 479         for_each_sk_fl_rcu(np, sfl)
 480                 count++;
 481         rcu_read_unlock_bh();
 482
 483         if (room <= 0 ||
 484             ((count >= FL_MAX_PER_SOCK ||
 485               (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) &&
 486              !capable(CAP_NET_ADMIN)))
 487                 return -ENOBUFS;
 488
 489         return 0;
 490 }
 491
 492 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
 493                 struct ip6_flowlabel *fl)
 494 {
 495         spin_lock_bh(&ip6_sk_fl_lock);
 496         sfl->fl = fl;
 497         sfl->next = np->ipv6_fl_list;
 498         rcu_assign_pointer(np->ipv6_fl_list, sfl);
 499         spin_unlock_bh(&ip6_sk_fl_lock);
 500 }
 501
 502 int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq,
 503                            int flags)
 504 {
 505         struct ipv6_pinfo *np = inet6_sk(sk);
 506         struct ipv6_fl_socklist *sfl;
 507
 508         if (flags & IPV6_FL_F_REMOTE) {
 509                 freq->flr_label = np->rcv_flowinfo & IPV6_FLOWLABEL_MASK;
 510                 return 0;
 511         }
 512
 513         if (np->repflow) {
 514                 freq->flr_label = np->flow_label;
 515                 return 0;
 516         }
 517
 518         rcu_read_lock_bh();
 519
 520         for_each_sk_fl_rcu(np, sfl) {
 521                 if (sfl->fl->label == (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 522                         spin_lock_bh(&ip6_fl_lock);
 523                         freq->flr_label = sfl->fl->label;
 524                         freq->flr_dst = sfl->fl->dst;
 525                         freq->flr_share = sfl->fl->share;
 526                         freq->flr_expires = (sfl->fl->expires - jiffies) / HZ;
 527                         freq->flr_linger = sfl->fl->linger / HZ;
 528
 529                         spin_unlock_bh(&ip6_fl_lock);
 530                         rcu_read_unlock_bh();
 531                         return 0;
 532                 }
 533         }
 534         rcu_read_unlock_bh();
 535
 536         return -ENOENT;
 537 }
 538
 539 #define socklist_dereference(__sflp) \
 540         rcu_dereference_protected(__sflp, lockdep_is_held(&ip6_sk_fl_lock))
 541
 542 static int ipv6_flowlabel_put(struct sock *sk, struct in6_flowlabel_req *freq)
 543 {
 544         struct ipv6_pinfo *np = inet6_sk(sk);
 545         struct ipv6_fl_socklist __rcu **sflp;
 546         struct ipv6_fl_socklist *sfl;
 547
 548         if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 549                 if (sk->sk_protocol != IPPROTO_TCP)
 550                         return -ENOPROTOOPT;
 551                 if (!np->repflow)
 552                         return -ESRCH;
 553                 np->flow_label = 0;
 554                 np->repflow = 0;
 555                 return 0;
 556         }
 557
 558         spin_lock_bh(&ip6_sk_fl_lock);
 559         for (sflp = &np->ipv6_fl_list;
 560              (sfl = socklist_dereference(*sflp)) != NULL;
 561              sflp = &sfl->next) {
 562                 if (sfl->fl->label == freq->flr_label)
 563                         goto found;
 564         }
 565         spin_unlock_bh(&ip6_sk_fl_lock);
 566         return -ESRCH;
 567 found:
 568         if (freq->flr_label == (np->flow_label & IPV6_FLOWLABEL_MASK))
 569                 np->flow_label &= ~IPV6_FLOWLABEL_MASK;
 570         *sflp = sfl->next;
 571         spin_unlock_bh(&ip6_sk_fl_lock);
 572         fl_release(sfl->fl);
 573         kfree_rcu(sfl, rcu);
 574         return 0;
 575 }
 576
 577 static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq)
 578 {
 579         struct ipv6_pinfo *np = inet6_sk(sk);
 580         struct net *net = sock_net(sk);
 581         struct ipv6_fl_socklist *sfl;
 582         int err;
 583
 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,
 588                                         freq->flr_expires);
 589                         rcu_read_unlock_bh();
 590                         return err;
 591                 }
 592         }
 593         rcu_read_unlock_bh();
 594
 595         if (freq->flr_share == IPV6_FL_S_NONE &&
 596             ns_capable(net->user_ns, CAP_NET_ADMIN)) {
 597                 struct ip6_flowlabel *fl = fl_lookup(net, freq->flr_label);
 598
 599                 if (fl) {
 600                         err = fl6_renew(fl, freq->flr_linger,
 601                                         freq->flr_expires);
 602                         fl_release(fl);
 603                         return err;
 604                 }
 605         }
 606         return -ESRCH;
 607 }
 608
 609 static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq,
 610                 sockptr_t optval, int optlen)
 611 {
 612         struct ipv6_fl_socklist *sfl, *sfl1 = NULL;
 613         struct ip6_flowlabel *fl, *fl1 = NULL;
 614         struct ipv6_pinfo *np = inet6_sk(sk);
 615         struct net *net = sock_net(sk);
 616         int err;
 617
 618         if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 619                 if (net->ipv6.sysctl.flowlabel_consistency) {
 620                         net_info_ratelimited("Can not set IPV6_FL_F_REFLECT if flowlabel_consistency sysctl is enable\n");
 621                         return -EPERM;
 622                 }
 623
 624                 if (sk->sk_protocol != IPPROTO_TCP)
 625                         return -ENOPROTOOPT;
 626                 np->repflow = 1;
 627                 return 0;
 628         }
 629
 630         if (freq->flr_label & ~IPV6_FLOWLABEL_MASK)
 631                 return -EINVAL;
 632         if (net->ipv6.sysctl.flowlabel_state_ranges &&
 633             (freq->flr_label & IPV6_FLOWLABEL_STATELESS_FLAG))
 634                 return -ERANGE;
 635
 636         fl = fl_create(net, sk, freq, optval, optlen, &err);
 637         if (!fl)
 638                 return err;
 639
 640         sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL);
 641
 642         if (freq->flr_label) {
 643                 err = -EEXIST;
 644                 rcu_read_lock_bh();
 645                 for_each_sk_fl_rcu(np, sfl) {
 646                         if (sfl->fl->label == freq->flr_label) {
 647                                 if (freq->flr_flags & IPV6_FL_F_EXCL) {
 648                                         rcu_read_unlock_bh();
 649                                         goto done;
 650                                 }
 651                                 fl1 = sfl->fl;
 652                                 if (!atomic_inc_not_zero(&fl1->users))
 653                                         fl1 = NULL;
 654                                 break;
 655                         }
 656                 }
 657                 rcu_read_unlock_bh();
 658
 659                 if (!fl1)
 660                         fl1 = fl_lookup(net, freq->flr_label);
 661                 if (fl1) {
 662 recheck:
 663                         err = -EEXIST;
 664                         if (freq->flr_flags&IPV6_FL_F_EXCL)
 665                                 goto release;
 666                         err = -EPERM;
 667                         if (fl1->share == IPV6_FL_S_EXCL ||
 668                             fl1->share != fl->share ||
 669                             ((fl1->share == IPV6_FL_S_PROCESS) &&
 670                              (fl1->owner.pid != fl->owner.pid)) ||
 671                             ((fl1->share == IPV6_FL_S_USER) &&
 672                              !uid_eq(fl1->owner.uid, fl->owner.uid)))
 673                                 goto release;
 674
 675                         err = -ENOMEM;
 676                         if (!sfl1)
 677                                 goto release;
 678                         if (fl->linger > fl1->linger)
 679                                 fl1->linger = fl->linger;
 680                         if ((long)(fl->expires - fl1->expires) > 0)
 681                                 fl1->expires = fl->expires;
 682                         fl_link(np, sfl1, fl1);
 683                         fl_free(fl);
 684                         return 0;
 685
 686 release:
 687                         fl_release(fl1);
 688                         goto done;
 689                 }
 690         }
 691         err = -ENOENT;
 692         if (!(freq->flr_flags & IPV6_FL_F_CREATE))
 693                 goto done;
 694
 695         err = -ENOMEM;
 696         if (!sfl1)
 697                 goto done;
 698
 699         err = mem_check(sk);
 700         if (err != 0)
 701                 goto done;
 702
 703         fl1 = fl_intern(net, fl, freq->flr_label);
 704         if (fl1)
 705                 goto recheck;
 706
 707         if (!freq->flr_label) {
 708                 size_t offset = offsetof(struct in6_flowlabel_req, flr_label);
 709
 710                 if (copy_to_sockptr_offset(optval, offset, &fl->label,
 711                                 sizeof(fl->label))) {
 712                         /* Intentionally ignore fault. */
 713                 }
 714         }
 715
 716         fl_link(np, sfl1, fl);
 717         return 0;
 718 done:
 719         fl_free(fl);
 720         kfree(sfl1);
 721         return err;
 722 }
 723
 724 int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen)
 725 {
 726         struct in6_flowlabel_req freq;
 727
 728         if (optlen < sizeof(freq))
 729                 return -EINVAL;
 730         if (copy_from_sockptr(&freq, optval, sizeof(freq)))
 731                 return -EFAULT;
 732
 733         switch (freq.flr_action) {
 734         case IPV6_FL_A_PUT:
 735                 return ipv6_flowlabel_put(sk, &freq);
 736         case IPV6_FL_A_RENEW:
 737                 return ipv6_flowlabel_renew(sk, &freq);
 738         case IPV6_FL_A_GET:
 739                 return ipv6_flowlabel_get(sk, &freq, optval, optlen);
 740         default:
 741                 return -EINVAL;
 742         }
 743 }
 744
 745 #ifdef CONFIG_PROC_FS
 746
 747 struct ip6fl_iter_state {
 748         struct seq_net_private p;
 749         struct pid_namespace *pid_ns;
 750         int bucket;
 751 };
 752
 753 #define ip6fl_seq_private(seq)  ((struct ip6fl_iter_state *)(seq)->private)
 754
 755 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq)
 756 {
 757         struct ip6_flowlabel *fl = NULL;
 758         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 759         struct net *net = seq_file_net(seq);
 760
 761         for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) {
 762                 for_each_fl_rcu(state->bucket, fl) {
 763                         if (net_eq(fl->fl_net, net))
 764                                 goto out;
 765                 }
 766         }
 767         fl = NULL;
 768 out:
 769         return fl;
 770 }
 771
 772 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl)
 773 {
 774         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 775         struct net *net = seq_file_net(seq);
 776
 777         for_each_fl_continue_rcu(fl) {
 778                 if (net_eq(fl->fl_net, net))
 779                         goto out;
 780         }
 781
 782 try_again:
 783         if (++state->bucket <= FL_HASH_MASK) {
 784                 for_each_fl_rcu(state->bucket, fl) {
 785                         if (net_eq(fl->fl_net, net))
 786                                 goto out;
 787                 }
 788                 goto try_again;
 789         }
 790         fl = NULL;
 791
 792 out:
 793         return fl;
 794 }
 795
 796 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos)
 797 {
 798         struct ip6_flowlabel *fl = ip6fl_get_first(seq);
 799         if (fl)
 800                 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL)
 801                         --pos;
 802         return pos ? NULL : fl;
 803 }
 804
 805 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos)
 806         __acquires(RCU)
 807 {
 808         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 809
 810         state->pid_ns = proc_pid_ns(file_inode(seq->file)->i_sb);
 811
 812         rcu_read_lock_bh();
 813         return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
 814 }
 815
 816 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 817 {
 818         struct ip6_flowlabel *fl;
 819
 820         if (v == SEQ_START_TOKEN)
 821                 fl = ip6fl_get_first(seq);
 822         else
 823                 fl = ip6fl_get_next(seq, v);
 824         ++*pos;
 825         return fl;
 826 }
 827
 828 static void ip6fl_seq_stop(struct seq_file *seq, void *v)
 829         __releases(RCU)
 830 {
 831         rcu_read_unlock_bh();
 832 }
 833
 834 static int ip6fl_seq_show(struct seq_file *seq, void *v)
 835 {
 836         struct ip6fl_iter_state *state = ip6fl_seq_private(seq);
 837         if (v == SEQ_START_TOKEN) {
 838                 seq_puts(seq, "Label S Owner  Users  Linger Expires  Dst                              Opt\n");
 839         } else {
 840                 struct ip6_flowlabel *fl = v;
 841                 seq_printf(seq,
 842                            "%05X %-1d %-6d %-6d %-6ld %-8ld %pi6 %-4d\n",
 843                            (unsigned int)ntohl(fl->label),
 844                            fl->share,
 845                            ((fl->share == IPV6_FL_S_PROCESS) ?
 846                             pid_nr_ns(fl->owner.pid, state->pid_ns) :
 847                             ((fl->share == IPV6_FL_S_USER) ?
 848                              from_kuid_munged(seq_user_ns(seq), fl->owner.uid) :
 849                              0)),
 850                            atomic_read(&fl->users),
 851                            fl->linger/HZ,
 852                            (long)(fl->expires - jiffies)/HZ,
 853                            &fl->dst,
 854                            fl->opt ? fl->opt->opt_nflen : 0);
 855         }
 856         return 0;
 857 }
 858
 859 static const struct seq_operations ip6fl_seq_ops = {
 860         .start  =       ip6fl_seq_start,
 861         .next   =       ip6fl_seq_next,
 862         .stop   =       ip6fl_seq_stop,
 863         .show   =       ip6fl_seq_show,
 864 };
 865
 866 static int __net_init ip6_flowlabel_proc_init(struct net *net)
 867 {
 868         if (!proc_create_net("ip6_flowlabel", 0444, net->proc_net,
 869                         &ip6fl_seq_ops, sizeof(struct ip6fl_iter_state)))
 870                 return -ENOMEM;
 871         return 0;
 872 }
 873
 874 static void __net_exit ip6_flowlabel_proc_fini(struct net *net)
 875 {
 876         remove_proc_entry("ip6_flowlabel", net->proc_net);
 877 }
 878 #else
 879 static inline int ip6_flowlabel_proc_init(struct net *net)
 880 {
 881         return 0;
 882 }
 883 static inline void ip6_flowlabel_proc_fini(struct net *net)
 884 {
 885 }
 886 #endif
 887
 888 static void __net_exit ip6_flowlabel_net_exit(struct net *net)
 889 {
 890         ip6_fl_purge(net);
 891         ip6_flowlabel_proc_fini(net);
 892 }
 893
 894 static struct pernet_operations ip6_flowlabel_net_ops = {
 895         .init = ip6_flowlabel_proc_init,
 896         .exit = ip6_flowlabel_net_exit,
 897 };
 898
 899 int ip6_flowlabel_init(void)
 900 {
 901         return register_pernet_subsys(&ip6_flowlabel_net_ops);
 902 }
 903
 904 void ip6_flowlabel_cleanup(void)
 905 {
 906         static_key_deferred_flush(&ipv6_flowlabel_exclusive);
 907         del_timer(&ip6_fl_gc_timer);
 908         unregister_pernet_subsys(&ip6_flowlabel_net_ops);
 909 }