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/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 #ifdef CONFIG_NETFILTER_EGRESS
 311         if (hooknum == NF_NETDEV_EGRESS) {
 312                 if (dev && dev_net(dev) == net)
 313                         return &dev->nf_hooks_egress;
 314         }
 315 #endif
 316         WARN_ON_ONCE(1);
 317         return NULL;
 318 }
 319
 320 static int __nf_register_net_hook(struct net *net, int pf,
 321                                   const struct nf_hook_ops *reg)
 322 {
 323         struct nf_hook_entries *p, *new_hooks;
 324         struct nf_hook_entries __rcu **pp;
 325
 326         if (pf == NFPROTO_NETDEV) {
 327                 if ((!IS_ENABLED(CONFIG_NETFILTER_INGRESS) &&
 328                      reg->hooknum == NF_NETDEV_INGRESS) ||
 329                     (!IS_ENABLED(CONFIG_NETFILTER_EGRESS) &&
 330                      reg->hooknum == NF_NETDEV_EGRESS))
 331                         return -EOPNOTSUPP;
 332                 if ((reg->hooknum != NF_NETDEV_INGRESS &&
 333                      reg->hooknum != NF_NETDEV_EGRESS) ||
 334                     !reg->dev || dev_net(reg->dev) != net)
 335                         return -EINVAL;
 336         }
 337
 338         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 339         if (!pp)
 340                 return -EINVAL;
 341
 342         mutex_lock(&nf_hook_mutex);
 343
 344         p = nf_entry_dereference(*pp);
 345         new_hooks = nf_hook_entries_grow(p, reg);
 346
 347         if (!IS_ERR(new_hooks))
 348                 rcu_assign_pointer(*pp, new_hooks);
 349
 350         mutex_unlock(&nf_hook_mutex);
 351         if (IS_ERR(new_hooks))
 352                 return PTR_ERR(new_hooks);
 353
 354         hooks_validate(new_hooks);
 355 #ifdef CONFIG_NETFILTER_INGRESS
 356         if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
 357                 net_inc_ingress_queue();
 358 #endif
 359 #ifdef CONFIG_NETFILTER_EGRESS
 360         if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS)
 361                 net_inc_egress_queue();
 362 #endif
 363 #ifdef CONFIG_JUMP_LABEL
 364         static_key_slow_inc(&nf_hooks_needed[pf][reg->hooknum]);
 365 #endif
 366         BUG_ON(p == new_hooks);
 367         nf_hook_entries_free(p);
 368         return 0;
 369 }
 370
 371 /*
 372  * nf_remove_net_hook - remove a hook from blob
 373  *
 374  * @oldp: current address of hook blob
 375  * @unreg: hook to unregister
 376  *
 377  * This cannot fail, hook unregistration must always succeed.
 378  * Therefore replace the to-be-removed hook with a dummy hook.
 379  */
 380 static bool nf_remove_net_hook(struct nf_hook_entries *old,
 381                                const struct nf_hook_ops *unreg)
 382 {
 383         struct nf_hook_ops **orig_ops;
 384         unsigned int i;
 385
 386         orig_ops = nf_hook_entries_get_hook_ops(old);
 387         for (i = 0; i < old->num_hook_entries; i++) {
 388                 if (orig_ops[i] != unreg)
 389                         continue;
 390                 WRITE_ONCE(old->hooks[i].hook, accept_all);
 391                 WRITE_ONCE(orig_ops[i], &dummy_ops);
 392                 return true;
 393         }
 394
 395         return false;
 396 }
 397
 398 static void __nf_unregister_net_hook(struct net *net, int pf,
 399                                      const struct nf_hook_ops *reg)
 400 {
 401         struct nf_hook_entries __rcu **pp;
 402         struct nf_hook_entries *p;
 403
 404         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 405         if (!pp)
 406                 return;
 407
 408         mutex_lock(&nf_hook_mutex);
 409
 410         p = nf_entry_dereference(*pp);
 411         if (WARN_ON_ONCE(!p)) {
 412                 mutex_unlock(&nf_hook_mutex);
 413                 return;
 414         }
 415
 416         if (nf_remove_net_hook(p, reg)) {
 417 #ifdef CONFIG_NETFILTER_INGRESS
 418                 if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
 419                         net_dec_ingress_queue();
 420 #endif
 421 #ifdef CONFIG_NETFILTER_EGRESS
 422                 if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS)
 423                         net_dec_egress_queue();
 424 #endif
 425 #ifdef CONFIG_JUMP_LABEL
 426                 static_key_slow_dec(&nf_hooks_needed[pf][reg->hooknum]);
 427 #endif
 428         } else {
 429                 WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
 430         }
 431
 432         p = __nf_hook_entries_try_shrink(p, pp);
 433         mutex_unlock(&nf_hook_mutex);
 434         if (!p)
 435                 return;
 436
 437         nf_queue_nf_hook_drop(net);
 438         nf_hook_entries_free(p);
 439 }
 440
 441 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 442 {
 443         if (reg->pf == NFPROTO_INET) {
 444                 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 445                 __nf_unregister_net_hook(net, NFPROTO_IPV6, reg);
 446         } else {
 447                 __nf_unregister_net_hook(net, reg->pf, reg);
 448         }
 449 }
 450 EXPORT_SYMBOL(nf_unregister_net_hook);
 451
 452 void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
 453                                 const struct nf_hook_ops *reg)
 454 {
 455         struct nf_hook_entries *p;
 456
 457         p = rcu_dereference_raw(*pp);
 458         if (nf_remove_net_hook(p, reg)) {
 459                 p = __nf_hook_entries_try_shrink(p, pp);
 460                 nf_hook_entries_free(p);
 461         }
 462 }
 463 EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
 464
 465 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 466 {
 467         int err;
 468
 469         if (reg->pf == NFPROTO_INET) {
 470                 err = __nf_register_net_hook(net, NFPROTO_IPV4, reg);
 471                 if (err < 0)
 472                         return err;
 473
 474                 err = __nf_register_net_hook(net, NFPROTO_IPV6, reg);
 475                 if (err < 0) {
 476                         __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 477                         return err;
 478                 }
 479         } else {
 480                 err = __nf_register_net_hook(net, reg->pf, reg);
 481                 if (err < 0)
 482                         return err;
 483         }
 484
 485         return 0;
 486 }
 487 EXPORT_SYMBOL(nf_register_net_hook);
 488
 489 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 490                           unsigned int n)
 491 {
 492         unsigned int i;
 493         int err = 0;
 494
 495         for (i = 0; i < n; i++) {
 496                 err = nf_register_net_hook(net, &reg[i]);
 497                 if (err)
 498                         goto err;
 499         }
 500         return err;
 501
 502 err:
 503         if (i > 0)
 504                 nf_unregister_net_hooks(net, reg, i);
 505         return err;
 506 }
 507 EXPORT_SYMBOL(nf_register_net_hooks);
 508
 509 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 510                              unsigned int hookcount)
 511 {
 512         unsigned int i;
 513
 514         for (i = 0; i < hookcount; i++)
 515                 nf_unregister_net_hook(net, &reg[i]);
 516 }
 517 EXPORT_SYMBOL(nf_unregister_net_hooks);
 518
 519 /* Returns 1 if okfn() needs to be executed by the caller,
 520  * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 521 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 522                  const struct nf_hook_entries *e, unsigned int s)
 523 {
 524         unsigned int verdict;
 525         int ret;
 526
 527         for (; s < e->num_hook_entries; s++) {
 528                 verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state);
 529                 switch (verdict & NF_VERDICT_MASK) {
 530                 case NF_ACCEPT:
 531                         break;
 532                 case NF_DROP:
 533                         kfree_skb(skb);
 534                         ret = NF_DROP_GETERR(verdict);
 535                         if (ret == 0)
 536                                 ret = -EPERM;
 537                         return ret;
 538                 case NF_QUEUE:
 539                         ret = nf_queue(skb, state, s, verdict);
 540                         if (ret == 1)
 541                                 continue;
 542                         return ret;
 543                 default:
 544                         /* Implicit handling for NF_STOLEN, as well as any other
 545                          * non conventional verdicts.
 546                          */
 547                         return 0;
 548                 }
 549         }
 550
 551         return 1;
 552 }
 553 EXPORT_SYMBOL(nf_hook_slow);
 554
 555 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
 556                        const struct nf_hook_entries *e)
 557 {
 558         struct sk_buff *skb, *next;
 559         struct list_head sublist;
 560         int ret;
 561
 562         INIT_LIST_HEAD(&sublist);
 563
 564         list_for_each_entry_safe(skb, next, head, list) {
 565                 skb_list_del_init(skb);
 566                 ret = nf_hook_slow(skb, state, e, 0);
 567                 if (ret == 1)
 568                         list_add_tail(&skb->list, &sublist);
 569         }
 570         /* Put passed packets back on main list */
 571         list_splice(&sublist, head);
 572 }
 573 EXPORT_SYMBOL(nf_hook_slow_list);
 574
 575 /* This needs to be compiled in any case to avoid dependencies between the
 576  * nfnetlink_queue code and nf_conntrack.
 577  */
 578 struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
 579 EXPORT_SYMBOL_GPL(nfnl_ct_hook);
 580
 581 struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
 582 EXPORT_SYMBOL_GPL(nf_ct_hook);
 583
 584 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 585 /* This does not belong here, but locally generated errors need it if connection
 586    tracking in use: without this, connection may not be in hash table, and hence
 587    manufactured ICMP or RST packets will not be associated with it. */
 588 void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *)
 589                 __rcu __read_mostly;
 590 EXPORT_SYMBOL(ip_ct_attach);
 591
 592 struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
 593 EXPORT_SYMBOL_GPL(nf_nat_hook);
 594
 595 void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
 596 {
 597         void (*attach)(struct sk_buff *, const struct sk_buff *);
 598
 599         if (skb->_nfct) {
 600                 rcu_read_lock();
 601                 attach = rcu_dereference(ip_ct_attach);
 602                 if (attach)
 603                         attach(new, skb);
 604                 rcu_read_unlock();
 605         }
 606 }
 607 EXPORT_SYMBOL(nf_ct_attach);
 608
 609 void nf_conntrack_destroy(struct nf_conntrack *nfct)
 610 {
 611         struct nf_ct_hook *ct_hook;
 612
 613         rcu_read_lock();
 614         ct_hook = rcu_dereference(nf_ct_hook);
 615         BUG_ON(ct_hook == NULL);
 616         ct_hook->destroy(nfct);
 617         rcu_read_unlock();
 618 }
 619 EXPORT_SYMBOL(nf_conntrack_destroy);
 620
 621 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 622                          const struct sk_buff *skb)
 623 {
 624         struct nf_ct_hook *ct_hook;
 625         bool ret = false;
 626
 627         rcu_read_lock();
 628         ct_hook = rcu_dereference(nf_ct_hook);
 629         if (ct_hook)
 630                 ret = ct_hook->get_tuple_skb(dst_tuple, skb);
 631         rcu_read_unlock();
 632         return ret;
 633 }
 634 EXPORT_SYMBOL(nf_ct_get_tuple_skb);
 635
 636 /* Built-in default zone used e.g. by modules. */
 637 const struct nf_conntrack_zone nf_ct_zone_dflt = {
 638         .id     = NF_CT_DEFAULT_ZONE_ID,
 639         .dir    = NF_CT_DEFAULT_ZONE_DIR,
 640 };
 641 EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
 642 #endif /* CONFIG_NF_CONNTRACK */
 643
 644 static void __net_init
 645 __netfilter_net_init(struct nf_hook_entries __rcu **e, int max)
 646 {
 647         int h;
 648
 649         for (h = 0; h < max; h++)
 650                 RCU_INIT_POINTER(e[h], NULL);
 651 }
 652
 653 static int __net_init netfilter_net_init(struct net *net)
 654 {
 655         __netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
 656         __netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
 657 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 658         __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
 659 #endif
 660 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 661         __netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
 662 #endif
 663 #if IS_ENABLED(CONFIG_DECNET)
 664         __netfilter_net_init(net->nf.hooks_decnet, ARRAY_SIZE(net->nf.hooks_decnet));
 665 #endif
 666
 667 #ifdef CONFIG_PROC_FS
 668         net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
 669                                                 net->proc_net);
 670         if (!net->nf.proc_netfilter) {
 671                 if (!net_eq(net, &init_net))
 672                         pr_err("cannot create netfilter proc entry");
 673
 674                 return -ENOMEM;
 675         }
 676 #endif
 677
 678         return 0;
 679 }
 680
 681 static void __net_exit netfilter_net_exit(struct net *net)
 682 {
 683         remove_proc_entry("netfilter", net->proc_net);
 684 }
 685
 686 static struct pernet_operations netfilter_net_ops = {
 687         .init = netfilter_net_init,
 688         .exit = netfilter_net_exit,
 689 };
 690
 691 int __init netfilter_init(void)
 692 {
 693         int ret;
 694
 695         ret = register_pernet_subsys(&netfilter_net_ops);
 696         if (ret < 0)
 697                 goto err;
 698
 699         ret = netfilter_log_init();
 700         if (ret < 0)
 701                 goto err_pernet;
 702
 703         return 0;
 704 err_pernet:
 705         unregister_pernet_subsys(&netfilter_net_ops);
 706 err:
 707         return ret;
 708 }