root/net/netfilter/core.c

DEFINITIONS

1. allocate_hook_entries_size
2. __nf_hook_entries_free
3. nf_hook_entries_free
4. accept_all
5. nf_hook_entries_grow
6. hooks_validate
7. nf_hook_entries_insert_raw
8. __nf_hook_entries_try_shrink
9. nf_hook_entry_head
10. __nf_register_net_hook
11. nf_remove_net_hook
12. __nf_unregister_net_hook
13. nf_unregister_net_hook
14. nf_hook_entries_delete_raw
15. nf_register_net_hook
16. nf_register_net_hooks
17. nf_unregister_net_hooks
18. nf_hook_slow
19. nf_ct_attach
20. nf_conntrack_destroy
21. nf_ct_get_tuple_skb
22. __netfilter_net_init
23. netfilter_net_init
24. netfilter_net_exit
25. netfilter_init

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