net/netfilter/core.c

   1 /* netfilter.c: look after the filters for various protocols.
   2  * Heavily influenced by the old firewall.c by David Bonn and Alan Cox.
   3  *
   4  * Thanks to Rob `CmdrTaco' Malda for not influencing this code in any
   5  * way.
   6  *
   7  * This code is GPL.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/netfilter.h>
  11 #include <net/protocol.h>
  12 #include <linux/init.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/wait.h>
  15 #include <linux/module.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/if.h>
  18 #include <linux/netdevice.h>
  19 #include <linux/netfilter_ipv6.h>
  20 #include <linux/inetdevice.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/mutex.h>
  23 #include <linux/mm.h>
  24 #include <linux/rcupdate.h>
  25 #include <net/net_namespace.h>
  26 #include <net/sock.h>
  27
  28 #include "nf_internals.h"
  29
  30 const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly;
  31 EXPORT_SYMBOL_GPL(nf_ipv6_ops);
  32
  33 DEFINE_PER_CPU(bool, nf_skb_duplicated);
  34 EXPORT_SYMBOL_GPL(nf_skb_duplicated);
  35
  36 #ifdef CONFIG_JUMP_LABEL
  37 struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
  38 EXPORT_SYMBOL(nf_hooks_needed);
  39 #endif
  40
  41 static DEFINE_MUTEX(nf_hook_mutex);
  42
  43 /* max hooks per family/hooknum */
  44 #define MAX_HOOK_COUNT          1024
  45
  46 #define nf_entry_dereference(e) \
  47         rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))
  48
  49 static struct nf_hook_entries *allocate_hook_entries_size(u16 num)
  50 {
  51         struct nf_hook_entries *e;
  52         size_t alloc = sizeof(*e) +
  53                        sizeof(struct nf_hook_entry) * num +
  54                        sizeof(struct nf_hook_ops *) * num +
  55                        sizeof(struct nf_hook_entries_rcu_head);
  56
  57         if (num == 0)
  58                 return NULL;
  59
  60         e = kvzalloc(alloc, GFP_KERNEL);
  61         if (e)
  62                 e->num_hook_entries = num;
  63         return e;
  64 }
  65
  66 static void __nf_hook_entries_free(struct rcu_head *h)
  67 {
  68         struct nf_hook_entries_rcu_head *head;
  69
  70         head = container_of(h, struct nf_hook_entries_rcu_head, head);
  71         kvfree(head->allocation);
  72 }
  73
  74 static void nf_hook_entries_free(struct nf_hook_entries *e)
  75 {
  76         struct nf_hook_entries_rcu_head *head;
  77         struct nf_hook_ops **ops;
  78         unsigned int num;
  79
  80         if (!e)
  81                 return;
  82
  83         num = e->num_hook_entries;
  84         ops = nf_hook_entries_get_hook_ops(e);
  85         head = (void *)&ops[num];
  86         head->allocation = e;
  87         call_rcu(&head->head, __nf_hook_entries_free);
  88 }
  89
  90 static unsigned int accept_all(void *priv,
  91                                struct sk_buff *skb,
  92                                const struct nf_hook_state *state)
  93 {
  94         return NF_ACCEPT; /* ACCEPT makes nf_hook_slow call next hook */
  95 }
  96
  97 static const struct nf_hook_ops dummy_ops = {
  98         .hook = accept_all,
  99         .priority = INT_MIN,
 100 };
 101
 102 static struct nf_hook_entries *
 103 nf_hook_entries_grow(const struct nf_hook_entries *old,
 104                      const struct nf_hook_ops *reg)
 105 {
 106         unsigned int i, alloc_entries, nhooks, old_entries;
 107         struct nf_hook_ops **orig_ops = NULL;
 108         struct nf_hook_ops **new_ops;
 109         struct nf_hook_entries *new;
 110         bool inserted = false;
 111
 112         alloc_entries = 1;
 113         old_entries = old ? old->num_hook_entries : 0;
 114
 115         if (old) {
 116                 orig_ops = nf_hook_entries_get_hook_ops(old);
 117
 118                 for (i = 0; i < old_entries; i++) {
 119                         if (orig_ops[i] != &dummy_ops)
 120                                 alloc_entries++;
 121                 }
 122         }
 123
 124         if (alloc_entries > MAX_HOOK_COUNT)
 125                 return ERR_PTR(-E2BIG);
 126
 127         new = allocate_hook_entries_size(alloc_entries);
 128         if (!new)
 129                 return ERR_PTR(-ENOMEM);
 130
 131         new_ops = nf_hook_entries_get_hook_ops(new);
 132
 133         i = 0;
 134         nhooks = 0;
 135         while (i < old_entries) {
 136                 if (orig_ops[i] == &dummy_ops) {
 137                         ++i;
 138                         continue;
 139                 }
 140
 141                 if (inserted || reg->priority > orig_ops[i]->priority) {
 142                         new_ops[nhooks] = (void *)orig_ops[i];
 143                         new->hooks[nhooks] = old->hooks[i];
 144                         i++;
 145                 } else {
 146                         new_ops[nhooks] = (void *)reg;
 147                         new->hooks[nhooks].hook = reg->hook;
 148                         new->hooks[nhooks].priv = reg->priv;
 149                         inserted = true;
 150                 }
 151                 nhooks++;
 152         }
 153
 154         if (!inserted) {
 155                 new_ops[nhooks] = (void *)reg;
 156                 new->hooks[nhooks].hook = reg->hook;
 157                 new->hooks[nhooks].priv = reg->priv;
 158         }
 159
 160         return new;
 161 }
 162
 163 static void hooks_validate(const struct nf_hook_entries *hooks)
 164 {
 165 #ifdef CONFIG_DEBUG_KERNEL
 166         struct nf_hook_ops **orig_ops;
 167         int prio = INT_MIN;
 168         size_t i = 0;
 169
 170         orig_ops = nf_hook_entries_get_hook_ops(hooks);
 171
 172         for (i = 0; i < hooks->num_hook_entries; i++) {
 173                 if (orig_ops[i] == &dummy_ops)
 174                         continue;
 175
 176                 WARN_ON(orig_ops[i]->priority < prio);
 177
 178                 if (orig_ops[i]->priority > prio)
 179                         prio = orig_ops[i]->priority;
 180         }
 181 #endif
 182 }
 183
 184 int nf_hook_entries_insert_raw(struct nf_hook_entries __rcu **pp,
 185                                 const struct nf_hook_ops *reg)
 186 {
 187         struct nf_hook_entries *new_hooks;
 188         struct nf_hook_entries *p;
 189
 190         p = rcu_dereference_raw(*pp);
 191         new_hooks = nf_hook_entries_grow(p, reg);
 192         if (IS_ERR(new_hooks))
 193                 return PTR_ERR(new_hooks);
 194
 195         hooks_validate(new_hooks);
 196
 197         rcu_assign_pointer(*pp, new_hooks);
 198
 199         BUG_ON(p == new_hooks);
 200         nf_hook_entries_free(p);
 201         return 0;
 202 }
 203 EXPORT_SYMBOL_GPL(nf_hook_entries_insert_raw);
 204
 205 /*
 206  * __nf_hook_entries_try_shrink - try to shrink hook array
 207  *
 208  * @old -- current hook blob at @pp
 209  * @pp -- location of hook blob
 210  *
 211  * Hook unregistration must always succeed, so to-be-removed hooks
 212  * are replaced by a dummy one that will just move to next hook.
 213  *
 214  * This counts the current dummy hooks, attempts to allocate new blob,
 215  * copies the live hooks, then replaces and discards old one.
 216  *
 217  * return values:
 218  *
 219  * Returns address to free, or NULL.
 220  */
 221 static void *__nf_hook_entries_try_shrink(struct nf_hook_entries *old,
 222                                           struct nf_hook_entries __rcu **pp)
 223 {
 224         unsigned int i, j, skip = 0, hook_entries;
 225         struct nf_hook_entries *new = NULL;
 226         struct nf_hook_ops **orig_ops;
 227         struct nf_hook_ops **new_ops;
 228
 229         if (WARN_ON_ONCE(!old))
 230                 return NULL;
 231
 232         orig_ops = nf_hook_entries_get_hook_ops(old);
 233         for (i = 0; i < old->num_hook_entries; i++) {
 234                 if (orig_ops[i] == &dummy_ops)
 235                         skip++;
 236         }
 237
 238         /* if skip == hook_entries all hooks have been removed */
 239         hook_entries = old->num_hook_entries;
 240         if (skip == hook_entries)
 241                 goto out_assign;
 242
 243         if (skip == 0)
 244                 return NULL;
 245
 246         hook_entries -= skip;
 247         new = allocate_hook_entries_size(hook_entries);
 248         if (!new)
 249                 return NULL;
 250
 251         new_ops = nf_hook_entries_get_hook_ops(new);
 252         for (i = 0, j = 0; i < old->num_hook_entries; i++) {
 253                 if (orig_ops[i] == &dummy_ops)
 254                         continue;
 255                 new->hooks[j] = old->hooks[i];
 256                 new_ops[j] = (void *)orig_ops[i];
 257                 j++;
 258         }
 259         hooks_validate(new);
 260 out_assign:
 261         rcu_assign_pointer(*pp, new);
 262         return old;
 263 }
 264
 265 static struct nf_hook_entries __rcu **
 266 nf_hook_entry_head(struct net *net, int pf, unsigned int hooknum,
 267                    struct net_device *dev)
 268 {
 269         switch (pf) {
 270         case NFPROTO_NETDEV:
 271                 break;
 272 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 273         case NFPROTO_ARP:
 274                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_arp) <= hooknum))
 275                         return NULL;
 276                 return net->nf.hooks_arp + hooknum;
 277 #endif
 278 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 279         case NFPROTO_BRIDGE:
 280                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_bridge) <= hooknum))
 281                         return NULL;
 282                 return net->nf.hooks_bridge + hooknum;
 283 #endif
 284         case NFPROTO_IPV4:
 285                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= hooknum))
 286                         return NULL;
 287                 return net->nf.hooks_ipv4 + hooknum;
 288         case NFPROTO_IPV6:
 289                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv6) <= hooknum))
 290                         return NULL;
 291                 return net->nf.hooks_ipv6 + hooknum;
 292 #if IS_ENABLED(CONFIG_DECNET)
 293         case NFPROTO_DECNET:
 294                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_decnet) <= hooknum))
 295                         return NULL;
 296                 return net->nf.hooks_decnet + hooknum;
 297 #endif
 298         default:
 299                 WARN_ON_ONCE(1);
 300                 return NULL;
 301         }
 302
 303 #ifdef CONFIG_NETFILTER_INGRESS
 304         if (hooknum == NF_NETDEV_INGRESS) {
 305                 if (dev && dev_net(dev) == net)
 306                         return &dev->nf_hooks_ingress;
 307         }
 308 #endif
 309         WARN_ON_ONCE(1);
 310         return NULL;
 311 }
 312
 313 static int __nf_register_net_hook(struct net *net, int pf,
 314                                   const struct nf_hook_ops *reg)
 315 {
 316         struct nf_hook_entries *p, *new_hooks;
 317         struct nf_hook_entries __rcu **pp;
 318
 319         if (pf == NFPROTO_NETDEV) {
 320 #ifndef CONFIG_NETFILTER_INGRESS
 321                 if (reg->hooknum == NF_NETDEV_INGRESS)
 322                         return -EOPNOTSUPP;
 323 #endif
 324                 if (reg->hooknum != NF_NETDEV_INGRESS ||
 325                     !reg->dev || dev_net(reg->dev) != net)
 326                         return -EINVAL;
 327         }
 328
 329         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 330         if (!pp)
 331                 return -EINVAL;
 332
 333         mutex_lock(&nf_hook_mutex);
 334
 335         p = nf_entry_dereference(*pp);
 336         new_hooks = nf_hook_entries_grow(p, reg);
 337
 338         if (!IS_ERR(new_hooks))
 339                 rcu_assign_pointer(*pp, new_hooks);
 340
 341         mutex_unlock(&nf_hook_mutex);
 342         if (IS_ERR(new_hooks))
 343                 return PTR_ERR(new_hooks);
 344
 345         hooks_validate(new_hooks);
 346 #ifdef CONFIG_NETFILTER_INGRESS
 347         if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
 348                 net_inc_ingress_queue();
 349 #endif
 350 #ifdef CONFIG_JUMP_LABEL
 351         static_key_slow_inc(&nf_hooks_needed[pf][reg->hooknum]);
 352 #endif
 353         BUG_ON(p == new_hooks);
 354         nf_hook_entries_free(p);
 355         return 0;
 356 }
 357
 358 /*
 359  * nf_remove_net_hook - remove a hook from blob
 360  *
 361  * @oldp: current address of hook blob
 362  * @unreg: hook to unregister
 363  *
 364  * This cannot fail, hook unregistration must always succeed.
 365  * Therefore replace the to-be-removed hook with a dummy hook.
 366  */
 367 static bool nf_remove_net_hook(struct nf_hook_entries *old,
 368                                const struct nf_hook_ops *unreg)
 369 {
 370         struct nf_hook_ops **orig_ops;
 371         unsigned int i;
 372
 373         orig_ops = nf_hook_entries_get_hook_ops(old);
 374         for (i = 0; i < old->num_hook_entries; i++) {
 375                 if (orig_ops[i] != unreg)
 376                         continue;
 377                 WRITE_ONCE(old->hooks[i].hook, accept_all);
 378                 WRITE_ONCE(orig_ops[i], &dummy_ops);
 379                 return true;
 380         }
 381
 382         return false;
 383 }
 384
 385 static void __nf_unregister_net_hook(struct net *net, int pf,
 386                                      const struct nf_hook_ops *reg)
 387 {
 388         struct nf_hook_entries __rcu **pp;
 389         struct nf_hook_entries *p;
 390
 391         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 392         if (!pp)
 393                 return;
 394
 395         mutex_lock(&nf_hook_mutex);
 396
 397         p = nf_entry_dereference(*pp);
 398         if (WARN_ON_ONCE(!p)) {
 399                 mutex_unlock(&nf_hook_mutex);
 400                 return;
 401         }
 402
 403         if (nf_remove_net_hook(p, reg)) {
 404 #ifdef CONFIG_NETFILTER_INGRESS
 405                 if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
 406                         net_dec_ingress_queue();
 407 #endif
 408 #ifdef CONFIG_JUMP_LABEL
 409                 static_key_slow_dec(&nf_hooks_needed[pf][reg->hooknum]);
 410 #endif
 411         } else {
 412                 WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
 413         }
 414
 415         p = __nf_hook_entries_try_shrink(p, pp);
 416         mutex_unlock(&nf_hook_mutex);
 417         if (!p)
 418                 return;
 419
 420         nf_queue_nf_hook_drop(net);
 421         nf_hook_entries_free(p);
 422 }
 423
 424 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 425 {
 426         if (reg->pf == NFPROTO_INET) {
 427                 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 428                 __nf_unregister_net_hook(net, NFPROTO_IPV6, reg);
 429         } else {
 430                 __nf_unregister_net_hook(net, reg->pf, reg);
 431         }
 432 }
 433 EXPORT_SYMBOL(nf_unregister_net_hook);
 434
 435 void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
 436                                 const struct nf_hook_ops *reg)
 437 {
 438         struct nf_hook_entries *p;
 439
 440         p = rcu_dereference_raw(*pp);
 441         if (nf_remove_net_hook(p, reg)) {
 442                 p = __nf_hook_entries_try_shrink(p, pp);
 443                 nf_hook_entries_free(p);
 444         }
 445 }
 446 EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
 447
 448 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 449 {
 450         int err;
 451
 452         if (reg->pf == NFPROTO_INET) {
 453                 err = __nf_register_net_hook(net, NFPROTO_IPV4, reg);
 454                 if (err < 0)
 455                         return err;
 456
 457                 err = __nf_register_net_hook(net, NFPROTO_IPV6, reg);
 458                 if (err < 0) {
 459                         __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 460                         return err;
 461                 }
 462         } else {
 463                 err = __nf_register_net_hook(net, reg->pf, reg);
 464                 if (err < 0)
 465                         return err;
 466         }
 467
 468         return 0;
 469 }
 470 EXPORT_SYMBOL(nf_register_net_hook);
 471
 472 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 473                           unsigned int n)
 474 {
 475         unsigned int i;
 476         int err = 0;
 477
 478         for (i = 0; i < n; i++) {
 479                 err = nf_register_net_hook(net, &reg[i]);
 480                 if (err)
 481                         goto err;
 482         }
 483         return err;
 484
 485 err:
 486         if (i > 0)
 487                 nf_unregister_net_hooks(net, reg, i);
 488         return err;
 489 }
 490 EXPORT_SYMBOL(nf_register_net_hooks);
 491
 492 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 493                              unsigned int hookcount)
 494 {
 495         unsigned int i;
 496
 497         for (i = 0; i < hookcount; i++)
 498                 nf_unregister_net_hook(net, &reg[i]);
 499 }
 500 EXPORT_SYMBOL(nf_unregister_net_hooks);
 501
 502 /* Returns 1 if okfn() needs to be executed by the caller,
 503  * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 504 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 505                  const struct nf_hook_entries *e, unsigned int s)
 506 {
 507         unsigned int verdict;
 508         int ret;
 509
 510         for (; s < e->num_hook_entries; s++) {
 511                 verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state);
 512                 switch (verdict & NF_VERDICT_MASK) {
 513                 case NF_ACCEPT:
 514                         break;
 515                 case NF_DROP:
 516                         kfree_skb(skb);
 517                         ret = NF_DROP_GETERR(verdict);
 518                         if (ret == 0)
 519                                 ret = -EPERM;
 520                         return ret;
 521                 case NF_QUEUE:
 522                         ret = nf_queue(skb, state, e, s, verdict);
 523                         if (ret == 1)
 524                                 continue;
 525                         return ret;
 526                 default:
 527                         /* Implicit handling for NF_STOLEN, as well as any other
 528                          * non conventional verdicts.
 529                          */
 530                         return 0;
 531                 }
 532         }
 533
 534         return 1;
 535 }
 536 EXPORT_SYMBOL(nf_hook_slow);
 537
 538
 539 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len)
 540 {
 541         if (writable_len > skb->len)
 542                 return 0;
 543
 544         /* Not exclusive use of packet?  Must copy. */
 545         if (!skb_cloned(skb)) {
 546                 if (writable_len <= skb_headlen(skb))
 547                         return 1;
 548         } else if (skb_clone_writable(skb, writable_len))
 549                 return 1;
 550
 551         if (writable_len <= skb_headlen(skb))
 552                 writable_len = 0;
 553         else
 554                 writable_len -= skb_headlen(skb);
 555
 556         return !!__pskb_pull_tail(skb, writable_len);
 557 }
 558 EXPORT_SYMBOL(skb_make_writable);
 559
 560 /* This needs to be compiled in any case to avoid dependencies between the
 561  * nfnetlink_queue code and nf_conntrack.
 562  */
 563 struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
 564 EXPORT_SYMBOL_GPL(nfnl_ct_hook);
 565
 566 struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
 567 EXPORT_SYMBOL_GPL(nf_ct_hook);
 568
 569 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 570 /* This does not belong here, but locally generated errors need it if connection
 571    tracking in use: without this, connection may not be in hash table, and hence
 572    manufactured ICMP or RST packets will not be associated with it. */
 573 void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *)
 574                 __rcu __read_mostly;
 575 EXPORT_SYMBOL(ip_ct_attach);
 576
 577 struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
 578 EXPORT_SYMBOL_GPL(nf_nat_hook);
 579
 580 void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
 581 {
 582         void (*attach)(struct sk_buff *, const struct sk_buff *);
 583
 584         if (skb->_nfct) {
 585                 rcu_read_lock();
 586                 attach = rcu_dereference(ip_ct_attach);
 587                 if (attach)
 588                         attach(new, skb);
 589                 rcu_read_unlock();
 590         }
 591 }
 592 EXPORT_SYMBOL(nf_ct_attach);
 593
 594 void nf_conntrack_destroy(struct nf_conntrack *nfct)
 595 {
 596         struct nf_ct_hook *ct_hook;
 597
 598         rcu_read_lock();
 599         ct_hook = rcu_dereference(nf_ct_hook);
 600         BUG_ON(ct_hook == NULL);
 601         ct_hook->destroy(nfct);
 602         rcu_read_unlock();
 603 }
 604 EXPORT_SYMBOL(nf_conntrack_destroy);
 605
 606 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 607                          const struct sk_buff *skb)
 608 {
 609         struct nf_ct_hook *ct_hook;
 610         bool ret = false;
 611
 612         rcu_read_lock();
 613         ct_hook = rcu_dereference(nf_ct_hook);
 614         if (ct_hook)
 615                 ret = ct_hook->get_tuple_skb(dst_tuple, skb);
 616         rcu_read_unlock();
 617         return ret;
 618 }
 619 EXPORT_SYMBOL(nf_ct_get_tuple_skb);
 620
 621 /* Built-in default zone used e.g. by modules. */
 622 const struct nf_conntrack_zone nf_ct_zone_dflt = {
 623         .id     = NF_CT_DEFAULT_ZONE_ID,
 624         .dir    = NF_CT_DEFAULT_ZONE_DIR,
 625 };
 626 EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
 627 #endif /* CONFIG_NF_CONNTRACK */
 628
 629 static void __net_init
 630 __netfilter_net_init(struct nf_hook_entries __rcu **e, int max)
 631 {
 632         int h;
 633
 634         for (h = 0; h < max; h++)
 635                 RCU_INIT_POINTER(e[h], NULL);
 636 }
 637
 638 static int __net_init netfilter_net_init(struct net *net)
 639 {
 640         __netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
 641         __netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
 642 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 643         __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
 644 #endif
 645 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 646         __netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
 647 #endif
 648 #if IS_ENABLED(CONFIG_DECNET)
 649         __netfilter_net_init(net->nf.hooks_decnet, ARRAY_SIZE(net->nf.hooks_decnet));
 650 #endif
 651
 652 #ifdef CONFIG_PROC_FS
 653         net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
 654                                                 net->proc_net);
 655         if (!net->nf.proc_netfilter) {
 656                 if (!net_eq(net, &init_net))
 657                         pr_err("cannot create netfilter proc entry");
 658
 659                 return -ENOMEM;
 660         }
 661 #endif
 662
 663         return 0;
 664 }
 665
 666 static void __net_exit netfilter_net_exit(struct net *net)
 667 {
 668         remove_proc_entry("netfilter", net->proc_net);
 669 }
 670
 671 static struct pernet_operations netfilter_net_ops = {
 672         .init = netfilter_net_init,
 673         .exit = netfilter_net_exit,
 674 };
 675
 676 int __init netfilter_init(void)
 677 {
 678         int ret;
 679
 680         ret = register_pernet_subsys(&netfilter_net_ops);
 681         if (ret < 0)
 682                 goto err;
 683
 684         ret = netfilter_log_init();
 685         if (ret < 0)
 686                 goto err_pernet;
 687
 688         return 0;
 689 err_pernet:
 690         unregister_pernet_subsys(&netfilter_net_ops);
 691 err:
 692         return ret;
 693 }