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 #ifdef CONFIG_NETFILTER_INGRESS
 286         case NFPROTO_INET:
 287                 if (WARN_ON_ONCE(hooknum != NF_INET_INGRESS))
 288                         return NULL;
 289                 if (!dev || dev_net(dev) != net) {
 290                         WARN_ON_ONCE(1);
 291                         return NULL;
 292                 }
 293                 return &dev->nf_hooks_ingress;
 294 #endif
 295         case NFPROTO_IPV4:
 296                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= hooknum))
 297                         return NULL;
 298                 return net->nf.hooks_ipv4 + hooknum;
 299         case NFPROTO_IPV6:
 300                 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv6) <= hooknum))
 301                         return NULL;
 302                 return net->nf.hooks_ipv6 + hooknum;
 303         default:
 304                 WARN_ON_ONCE(1);
 305                 return NULL;
 306         }
 307
 308 #ifdef CONFIG_NETFILTER_INGRESS
 309         if (hooknum == NF_NETDEV_INGRESS) {
 310                 if (dev && dev_net(dev) == net)
 311                         return &dev->nf_hooks_ingress;
 312         }
 313 #endif
 314         WARN_ON_ONCE(1);
 315         return NULL;
 316 }
 317
 318 static int nf_ingress_check(struct net *net, const struct nf_hook_ops *reg,
 319                             int hooknum)
 320 {
 321 #ifndef CONFIG_NETFILTER_INGRESS
 322         if (reg->hooknum == hooknum)
 323                 return -EOPNOTSUPP;
 324 #endif
 325         if (reg->hooknum != hooknum ||
 326             !reg->dev || dev_net(reg->dev) != net)
 327                 return -EINVAL;
 328
 329         return 0;
 330 }
 331
 332 static inline bool nf_ingress_hook(const struct nf_hook_ops *reg, int pf)
 333 {
 334         if ((pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) ||
 335             (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS))
 336                 return true;
 337
 338         return false;
 339 }
 340
 341 static void nf_static_key_inc(const struct nf_hook_ops *reg, int pf)
 342 {
 343 #ifdef CONFIG_JUMP_LABEL
 344         int hooknum;
 345
 346         if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
 347                 pf = NFPROTO_NETDEV;
 348                 hooknum = NF_NETDEV_INGRESS;
 349         } else {
 350                 hooknum = reg->hooknum;
 351         }
 352         static_key_slow_inc(&nf_hooks_needed[pf][hooknum]);
 353 #endif
 354 }
 355
 356 static void nf_static_key_dec(const struct nf_hook_ops *reg, int pf)
 357 {
 358 #ifdef CONFIG_JUMP_LABEL
 359         int hooknum;
 360
 361         if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
 362                 pf = NFPROTO_NETDEV;
 363                 hooknum = NF_NETDEV_INGRESS;
 364         } else {
 365                 hooknum = reg->hooknum;
 366         }
 367         static_key_slow_dec(&nf_hooks_needed[pf][hooknum]);
 368 #endif
 369 }
 370
 371 static int __nf_register_net_hook(struct net *net, int pf,
 372                                   const struct nf_hook_ops *reg)
 373 {
 374         struct nf_hook_entries *p, *new_hooks;
 375         struct nf_hook_entries __rcu **pp;
 376         int err;
 377
 378         switch (pf) {
 379         case NFPROTO_NETDEV:
 380                 err = nf_ingress_check(net, reg, NF_NETDEV_INGRESS);
 381                 if (err < 0)
 382                         return err;
 383                 break;
 384         case NFPROTO_INET:
 385                 if (reg->hooknum != NF_INET_INGRESS)
 386                         break;
 387
 388                 err = nf_ingress_check(net, reg, NF_INET_INGRESS);
 389                 if (err < 0)
 390                         return err;
 391                 break;
 392         }
 393
 394         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 395         if (!pp)
 396                 return -EINVAL;
 397
 398         mutex_lock(&nf_hook_mutex);
 399
 400         p = nf_entry_dereference(*pp);
 401         new_hooks = nf_hook_entries_grow(p, reg);
 402
 403         if (!IS_ERR(new_hooks)) {
 404                 hooks_validate(new_hooks);
 405                 rcu_assign_pointer(*pp, new_hooks);
 406         }
 407
 408         mutex_unlock(&nf_hook_mutex);
 409         if (IS_ERR(new_hooks))
 410                 return PTR_ERR(new_hooks);
 411
 412 #ifdef CONFIG_NETFILTER_INGRESS
 413         if (nf_ingress_hook(reg, pf))
 414                 net_inc_ingress_queue();
 415 #endif
 416         nf_static_key_inc(reg, pf);
 417
 418         BUG_ON(p == new_hooks);
 419         nf_hook_entries_free(p);
 420         return 0;
 421 }
 422
 423 /*
 424  * nf_remove_net_hook - remove a hook from blob
 425  *
 426  * @oldp: current address of hook blob
 427  * @unreg: hook to unregister
 428  *
 429  * This cannot fail, hook unregistration must always succeed.
 430  * Therefore replace the to-be-removed hook with a dummy hook.
 431  */
 432 static bool nf_remove_net_hook(struct nf_hook_entries *old,
 433                                const struct nf_hook_ops *unreg)
 434 {
 435         struct nf_hook_ops **orig_ops;
 436         unsigned int i;
 437
 438         orig_ops = nf_hook_entries_get_hook_ops(old);
 439         for (i = 0; i < old->num_hook_entries; i++) {
 440                 if (orig_ops[i] != unreg)
 441                         continue;
 442                 WRITE_ONCE(old->hooks[i].hook, accept_all);
 443                 WRITE_ONCE(orig_ops[i], (void *)&dummy_ops);
 444                 return true;
 445         }
 446
 447         return false;
 448 }
 449
 450 static void __nf_unregister_net_hook(struct net *net, int pf,
 451                                      const struct nf_hook_ops *reg)
 452 {
 453         struct nf_hook_entries __rcu **pp;
 454         struct nf_hook_entries *p;
 455
 456         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 457         if (!pp)
 458                 return;
 459
 460         mutex_lock(&nf_hook_mutex);
 461
 462         p = nf_entry_dereference(*pp);
 463         if (WARN_ON_ONCE(!p)) {
 464                 mutex_unlock(&nf_hook_mutex);
 465                 return;
 466         }
 467
 468         if (nf_remove_net_hook(p, reg)) {
 469 #ifdef CONFIG_NETFILTER_INGRESS
 470                 if (nf_ingress_hook(reg, pf))
 471                         net_dec_ingress_queue();
 472 #endif
 473                 nf_static_key_dec(reg, pf);
 474         } else {
 475                 WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
 476         }
 477
 478         p = __nf_hook_entries_try_shrink(p, pp);
 479         mutex_unlock(&nf_hook_mutex);
 480         if (!p)
 481                 return;
 482
 483         nf_queue_nf_hook_drop(net);
 484         nf_hook_entries_free(p);
 485 }
 486
 487 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 488 {
 489         if (reg->pf == NFPROTO_INET) {
 490                 if (reg->hooknum == NF_INET_INGRESS) {
 491                         __nf_unregister_net_hook(net, NFPROTO_INET, reg);
 492                 } else {
 493                         __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 494                         __nf_unregister_net_hook(net, NFPROTO_IPV6, reg);
 495                 }
 496         } else {
 497                 __nf_unregister_net_hook(net, reg->pf, reg);
 498         }
 499 }
 500 EXPORT_SYMBOL(nf_unregister_net_hook);
 501
 502 void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
 503                                 const struct nf_hook_ops *reg)
 504 {
 505         struct nf_hook_entries *p;
 506
 507         p = rcu_dereference_raw(*pp);
 508         if (nf_remove_net_hook(p, reg)) {
 509                 p = __nf_hook_entries_try_shrink(p, pp);
 510                 nf_hook_entries_free(p);
 511         }
 512 }
 513 EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
 514
 515 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 516 {
 517         int err;
 518
 519         if (reg->pf == NFPROTO_INET) {
 520                 if (reg->hooknum == NF_INET_INGRESS) {
 521                         err = __nf_register_net_hook(net, NFPROTO_INET, reg);
 522                         if (err < 0)
 523                                 return err;
 524                 } else {
 525                         err = __nf_register_net_hook(net, NFPROTO_IPV4, reg);
 526                         if (err < 0)
 527                                 return err;
 528
 529                         err = __nf_register_net_hook(net, NFPROTO_IPV6, reg);
 530                         if (err < 0) {
 531                                 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 532                                 return err;
 533                         }
 534                 }
 535         } else {
 536                 err = __nf_register_net_hook(net, reg->pf, reg);
 537                 if (err < 0)
 538                         return err;
 539         }
 540
 541         return 0;
 542 }
 543 EXPORT_SYMBOL(nf_register_net_hook);
 544
 545 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 546                           unsigned int n)
 547 {
 548         unsigned int i;
 549         int err = 0;
 550
 551         for (i = 0; i < n; i++) {
 552                 err = nf_register_net_hook(net, &reg[i]);
 553                 if (err)
 554                         goto err;
 555         }
 556         return err;
 557
 558 err:
 559         if (i > 0)
 560                 nf_unregister_net_hooks(net, reg, i);
 561         return err;
 562 }
 563 EXPORT_SYMBOL(nf_register_net_hooks);
 564
 565 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 566                              unsigned int hookcount)
 567 {
 568         unsigned int i;
 569
 570         for (i = 0; i < hookcount; i++)
 571                 nf_unregister_net_hook(net, &reg[i]);
 572 }
 573 EXPORT_SYMBOL(nf_unregister_net_hooks);
 574
 575 /* Returns 1 if okfn() needs to be executed by the caller,
 576  * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 577 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 578                  const struct nf_hook_entries *e, unsigned int s)
 579 {
 580         unsigned int verdict;
 581         int ret;
 582
 583         for (; s < e->num_hook_entries; s++) {
 584                 verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state);
 585                 switch (verdict & NF_VERDICT_MASK) {
 586                 case NF_ACCEPT:
 587                         break;
 588                 case NF_DROP:
 589                         kfree_skb(skb);
 590                         ret = NF_DROP_GETERR(verdict);
 591                         if (ret == 0)
 592                                 ret = -EPERM;
 593                         return ret;
 594                 case NF_QUEUE:
 595                         ret = nf_queue(skb, state, s, verdict);
 596                         if (ret == 1)
 597                                 continue;
 598                         return ret;
 599                 default:
 600                         /* Implicit handling for NF_STOLEN, as well as any other
 601                          * non conventional verdicts.
 602                          */
 603                         return 0;
 604                 }
 605         }
 606
 607         return 1;
 608 }
 609 EXPORT_SYMBOL(nf_hook_slow);
 610
 611 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
 612                        const struct nf_hook_entries *e)
 613 {
 614         struct sk_buff *skb, *next;
 615         struct list_head sublist;
 616         int ret;
 617
 618         INIT_LIST_HEAD(&sublist);
 619
 620         list_for_each_entry_safe(skb, next, head, list) {
 621                 skb_list_del_init(skb);
 622                 ret = nf_hook_slow(skb, state, e, 0);
 623                 if (ret == 1)
 624                         list_add_tail(&skb->list, &sublist);
 625         }
 626         /* Put passed packets back on main list */
 627         list_splice(&sublist, head);
 628 }
 629 EXPORT_SYMBOL(nf_hook_slow_list);
 630
 631 /* This needs to be compiled in any case to avoid dependencies between the
 632  * nfnetlink_queue code and nf_conntrack.
 633  */
 634 struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
 635 EXPORT_SYMBOL_GPL(nfnl_ct_hook);
 636
 637 struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
 638 EXPORT_SYMBOL_GPL(nf_ct_hook);
 639
 640 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 641 /* This does not belong here, but locally generated errors need it if connection
 642    tracking in use: without this, connection may not be in hash table, and hence
 643    manufactured ICMP or RST packets will not be associated with it. */
 644 void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *)
 645                 __rcu __read_mostly;
 646 EXPORT_SYMBOL(ip_ct_attach);
 647
 648 struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
 649 EXPORT_SYMBOL_GPL(nf_nat_hook);
 650
 651 void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
 652 {
 653         void (*attach)(struct sk_buff *, const struct sk_buff *);
 654
 655         if (skb->_nfct) {
 656                 rcu_read_lock();
 657                 attach = rcu_dereference(ip_ct_attach);
 658                 if (attach)
 659                         attach(new, skb);
 660                 rcu_read_unlock();
 661         }
 662 }
 663 EXPORT_SYMBOL(nf_ct_attach);
 664
 665 void nf_conntrack_destroy(struct nf_conntrack *nfct)
 666 {
 667         struct nf_ct_hook *ct_hook;
 668
 669         rcu_read_lock();
 670         ct_hook = rcu_dereference(nf_ct_hook);
 671         if (ct_hook)
 672                 ct_hook->destroy(nfct);
 673         rcu_read_unlock();
 674
 675         WARN_ON(!ct_hook);
 676 }
 677 EXPORT_SYMBOL(nf_conntrack_destroy);
 678
 679 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 680                          const struct sk_buff *skb)
 681 {
 682         struct nf_ct_hook *ct_hook;
 683         bool ret = false;
 684
 685         rcu_read_lock();
 686         ct_hook = rcu_dereference(nf_ct_hook);
 687         if (ct_hook)
 688                 ret = ct_hook->get_tuple_skb(dst_tuple, skb);
 689         rcu_read_unlock();
 690         return ret;
 691 }
 692 EXPORT_SYMBOL(nf_ct_get_tuple_skb);
 693
 694 /* Built-in default zone used e.g. by modules. */
 695 const struct nf_conntrack_zone nf_ct_zone_dflt = {
 696         .id     = NF_CT_DEFAULT_ZONE_ID,
 697         .dir    = NF_CT_DEFAULT_ZONE_DIR,
 698 };
 699 EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
 700 #endif /* CONFIG_NF_CONNTRACK */
 701
 702 static void __net_init
 703 __netfilter_net_init(struct nf_hook_entries __rcu **e, int max)
 704 {
 705         int h;
 706
 707         for (h = 0; h < max; h++)
 708                 RCU_INIT_POINTER(e[h], NULL);
 709 }
 710
 711 static int __net_init netfilter_net_init(struct net *net)
 712 {
 713         __netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
 714         __netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
 715 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 716         __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
 717 #endif
 718 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 719         __netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
 720 #endif
 721 #ifdef CONFIG_PROC_FS
 722         net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
 723                                                 net->proc_net);
 724         if (!net->nf.proc_netfilter) {
 725                 if (!net_eq(net, &init_net))
 726                         pr_err("cannot create netfilter proc entry");
 727
 728                 return -ENOMEM;
 729         }
 730 #endif
 731
 732         return 0;
 733 }
 734
 735 static void __net_exit netfilter_net_exit(struct net *net)
 736 {
 737         remove_proc_entry("netfilter", net->proc_net);
 738 }
 739
 740 static struct pernet_operations netfilter_net_ops = {
 741         .init = netfilter_net_init,
 742         .exit = netfilter_net_exit,
 743 };
 744
 745 int __init netfilter_init(void)
 746 {
 747         int ret;
 748
 749         ret = register_pernet_subsys(&netfilter_net_ops);
 750         if (ret < 0)
 751                 goto err;
 752
 753         ret = netfilter_log_init();
 754         if (ret < 0)
 755                 goto err_pernet;
 756
 757         return 0;
 758 err_pernet:
 759         unregister_pernet_subsys(&netfilter_net_ops);
 760 err:
 761         return ret;
 762 }