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_ACCOUNT);
  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 #ifdef CONFIG_NETFILTER_EGRESS
 315         if (hooknum == NF_NETDEV_EGRESS) {
 316                 if (dev && dev_net(dev) == net)
 317                         return &dev->nf_hooks_egress;
 318         }
 319 #endif
 320         WARN_ON_ONCE(1);
 321         return NULL;
 322 }
 323
 324 static int nf_ingress_check(struct net *net, const struct nf_hook_ops *reg,
 325                             int hooknum)
 326 {
 327 #ifndef CONFIG_NETFILTER_INGRESS
 328         if (reg->hooknum == hooknum)
 329                 return -EOPNOTSUPP;
 330 #endif
 331         if (reg->hooknum != hooknum ||
 332             !reg->dev || dev_net(reg->dev) != net)
 333                 return -EINVAL;
 334
 335         return 0;
 336 }
 337
 338 static inline bool __maybe_unused nf_ingress_hook(const struct nf_hook_ops *reg,
 339                                                   int pf)
 340 {
 341         if ((pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) ||
 342             (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS))
 343                 return true;
 344
 345         return false;
 346 }
 347
 348 static inline bool __maybe_unused nf_egress_hook(const struct nf_hook_ops *reg,
 349                                                  int pf)
 350 {
 351         return pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS;
 352 }
 353
 354 static void nf_static_key_inc(const struct nf_hook_ops *reg, int pf)
 355 {
 356 #ifdef CONFIG_JUMP_LABEL
 357         int hooknum;
 358
 359         if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
 360                 pf = NFPROTO_NETDEV;
 361                 hooknum = NF_NETDEV_INGRESS;
 362         } else {
 363                 hooknum = reg->hooknum;
 364         }
 365         static_key_slow_inc(&nf_hooks_needed[pf][hooknum]);
 366 #endif
 367 }
 368
 369 static void nf_static_key_dec(const struct nf_hook_ops *reg, int pf)
 370 {
 371 #ifdef CONFIG_JUMP_LABEL
 372         int hooknum;
 373
 374         if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
 375                 pf = NFPROTO_NETDEV;
 376                 hooknum = NF_NETDEV_INGRESS;
 377         } else {
 378                 hooknum = reg->hooknum;
 379         }
 380         static_key_slow_dec(&nf_hooks_needed[pf][hooknum]);
 381 #endif
 382 }
 383
 384 static int __nf_register_net_hook(struct net *net, int pf,
 385                                   const struct nf_hook_ops *reg)
 386 {
 387         struct nf_hook_entries *p, *new_hooks;
 388         struct nf_hook_entries __rcu **pp;
 389         int err;
 390
 391         switch (pf) {
 392         case NFPROTO_NETDEV:
 393 #ifndef CONFIG_NETFILTER_INGRESS
 394                 if (reg->hooknum == NF_NETDEV_INGRESS)
 395                         return -EOPNOTSUPP;
 396 #endif
 397 #ifndef CONFIG_NETFILTER_EGRESS
 398                 if (reg->hooknum == NF_NETDEV_EGRESS)
 399                         return -EOPNOTSUPP;
 400 #endif
 401                 if ((reg->hooknum != NF_NETDEV_INGRESS &&
 402                      reg->hooknum != NF_NETDEV_EGRESS) ||
 403                     !reg->dev || dev_net(reg->dev) != net)
 404                         return -EINVAL;
 405                 break;
 406         case NFPROTO_INET:
 407                 if (reg->hooknum != NF_INET_INGRESS)
 408                         break;
 409
 410                 err = nf_ingress_check(net, reg, NF_INET_INGRESS);
 411                 if (err < 0)
 412                         return err;
 413                 break;
 414         }
 415
 416         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 417         if (!pp)
 418                 return -EINVAL;
 419
 420         mutex_lock(&nf_hook_mutex);
 421
 422         p = nf_entry_dereference(*pp);
 423         new_hooks = nf_hook_entries_grow(p, reg);
 424
 425         if (!IS_ERR(new_hooks)) {
 426                 hooks_validate(new_hooks);
 427                 rcu_assign_pointer(*pp, new_hooks);
 428         }
 429
 430         mutex_unlock(&nf_hook_mutex);
 431         if (IS_ERR(new_hooks))
 432                 return PTR_ERR(new_hooks);
 433
 434 #ifdef CONFIG_NETFILTER_INGRESS
 435         if (nf_ingress_hook(reg, pf))
 436                 net_inc_ingress_queue();
 437 #endif
 438 #ifdef CONFIG_NETFILTER_EGRESS
 439         if (nf_egress_hook(reg, pf))
 440                 net_inc_egress_queue();
 441 #endif
 442         nf_static_key_inc(reg, pf);
 443
 444         BUG_ON(p == new_hooks);
 445         nf_hook_entries_free(p);
 446         return 0;
 447 }
 448
 449 /*
 450  * nf_remove_net_hook - remove a hook from blob
 451  *
 452  * @oldp: current address of hook blob
 453  * @unreg: hook to unregister
 454  *
 455  * This cannot fail, hook unregistration must always succeed.
 456  * Therefore replace the to-be-removed hook with a dummy hook.
 457  */
 458 static bool nf_remove_net_hook(struct nf_hook_entries *old,
 459                                const struct nf_hook_ops *unreg)
 460 {
 461         struct nf_hook_ops **orig_ops;
 462         unsigned int i;
 463
 464         orig_ops = nf_hook_entries_get_hook_ops(old);
 465         for (i = 0; i < old->num_hook_entries; i++) {
 466                 if (orig_ops[i] != unreg)
 467                         continue;
 468                 WRITE_ONCE(old->hooks[i].hook, accept_all);
 469                 WRITE_ONCE(orig_ops[i], (void *)&dummy_ops);
 470                 return true;
 471         }
 472
 473         return false;
 474 }
 475
 476 static void __nf_unregister_net_hook(struct net *net, int pf,
 477                                      const struct nf_hook_ops *reg)
 478 {
 479         struct nf_hook_entries __rcu **pp;
 480         struct nf_hook_entries *p;
 481
 482         pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
 483         if (!pp)
 484                 return;
 485
 486         mutex_lock(&nf_hook_mutex);
 487
 488         p = nf_entry_dereference(*pp);
 489         if (WARN_ON_ONCE(!p)) {
 490                 mutex_unlock(&nf_hook_mutex);
 491                 return;
 492         }
 493
 494         if (nf_remove_net_hook(p, reg)) {
 495 #ifdef CONFIG_NETFILTER_INGRESS
 496                 if (nf_ingress_hook(reg, pf))
 497                         net_dec_ingress_queue();
 498 #endif
 499 #ifdef CONFIG_NETFILTER_EGRESS
 500                 if (nf_egress_hook(reg, pf))
 501                         net_dec_egress_queue();
 502 #endif
 503                 nf_static_key_dec(reg, pf);
 504         } else {
 505                 WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
 506         }
 507
 508         p = __nf_hook_entries_try_shrink(p, pp);
 509         mutex_unlock(&nf_hook_mutex);
 510         if (!p)
 511                 return;
 512
 513         nf_queue_nf_hook_drop(net);
 514         nf_hook_entries_free(p);
 515 }
 516
 517 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 518 {
 519         if (reg->pf == NFPROTO_INET) {
 520                 if (reg->hooknum == NF_INET_INGRESS) {
 521                         __nf_unregister_net_hook(net, NFPROTO_INET, reg);
 522                 } else {
 523                         __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 524                         __nf_unregister_net_hook(net, NFPROTO_IPV6, reg);
 525                 }
 526         } else {
 527                 __nf_unregister_net_hook(net, reg->pf, reg);
 528         }
 529 }
 530 EXPORT_SYMBOL(nf_unregister_net_hook);
 531
 532 void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
 533                                 const struct nf_hook_ops *reg)
 534 {
 535         struct nf_hook_entries *p;
 536
 537         p = rcu_dereference_raw(*pp);
 538         if (nf_remove_net_hook(p, reg)) {
 539                 p = __nf_hook_entries_try_shrink(p, pp);
 540                 nf_hook_entries_free(p);
 541         }
 542 }
 543 EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
 544
 545 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 546 {
 547         int err;
 548
 549         if (reg->pf == NFPROTO_INET) {
 550                 if (reg->hooknum == NF_INET_INGRESS) {
 551                         err = __nf_register_net_hook(net, NFPROTO_INET, reg);
 552                         if (err < 0)
 553                                 return err;
 554                 } else {
 555                         err = __nf_register_net_hook(net, NFPROTO_IPV4, reg);
 556                         if (err < 0)
 557                                 return err;
 558
 559                         err = __nf_register_net_hook(net, NFPROTO_IPV6, reg);
 560                         if (err < 0) {
 561                                 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
 562                                 return err;
 563                         }
 564                 }
 565         } else {
 566                 err = __nf_register_net_hook(net, reg->pf, reg);
 567                 if (err < 0)
 568                         return err;
 569         }
 570
 571         return 0;
 572 }
 573 EXPORT_SYMBOL(nf_register_net_hook);
 574
 575 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 576                           unsigned int n)
 577 {
 578         unsigned int i;
 579         int err = 0;
 580
 581         for (i = 0; i < n; i++) {
 582                 err = nf_register_net_hook(net, &reg[i]);
 583                 if (err)
 584                         goto err;
 585         }
 586         return err;
 587
 588 err:
 589         if (i > 0)
 590                 nf_unregister_net_hooks(net, reg, i);
 591         return err;
 592 }
 593 EXPORT_SYMBOL(nf_register_net_hooks);
 594
 595 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
 596                              unsigned int hookcount)
 597 {
 598         unsigned int i;
 599
 600         for (i = 0; i < hookcount; i++)
 601                 nf_unregister_net_hook(net, &reg[i]);
 602 }
 603 EXPORT_SYMBOL(nf_unregister_net_hooks);
 604
 605 /* Returns 1 if okfn() needs to be executed by the caller,
 606  * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 607 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
 608                  const struct nf_hook_entries *e, unsigned int s)
 609 {
 610         unsigned int verdict;
 611         int ret;
 612
 613         for (; s < e->num_hook_entries; s++) {
 614                 verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state);
 615                 switch (verdict & NF_VERDICT_MASK) {
 616                 case NF_ACCEPT:
 617                         break;
 618                 case NF_DROP:
 619                         kfree_skb_reason(skb,
 620                                          SKB_DROP_REASON_NETFILTER_DROP);
 621                         ret = NF_DROP_GETERR(verdict);
 622                         if (ret == 0)
 623                                 ret = -EPERM;
 624                         return ret;
 625                 case NF_QUEUE:
 626                         ret = nf_queue(skb, state, s, verdict);
 627                         if (ret == 1)
 628                                 continue;
 629                         return ret;
 630                 default:
 631                         /* Implicit handling for NF_STOLEN, as well as any other
 632                          * non conventional verdicts.
 633                          */
 634                         return 0;
 635                 }
 636         }
 637
 638         return 1;
 639 }
 640 EXPORT_SYMBOL(nf_hook_slow);
 641
 642 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
 643                        const struct nf_hook_entries *e)
 644 {
 645         struct sk_buff *skb, *next;
 646         struct list_head sublist;
 647         int ret;
 648
 649         INIT_LIST_HEAD(&sublist);
 650
 651         list_for_each_entry_safe(skb, next, head, list) {
 652                 skb_list_del_init(skb);
 653                 ret = nf_hook_slow(skb, state, e, 0);
 654                 if (ret == 1)
 655                         list_add_tail(&skb->list, &sublist);
 656         }
 657         /* Put passed packets back on main list */
 658         list_splice(&sublist, head);
 659 }
 660 EXPORT_SYMBOL(nf_hook_slow_list);
 661
 662 /* This needs to be compiled in any case to avoid dependencies between the
 663  * nfnetlink_queue code and nf_conntrack.
 664  */
 665 const struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
 666 EXPORT_SYMBOL_GPL(nfnl_ct_hook);
 667
 668 const struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
 669 EXPORT_SYMBOL_GPL(nf_ct_hook);
 670
 671 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 672 u8 nf_ctnetlink_has_listener;
 673 EXPORT_SYMBOL_GPL(nf_ctnetlink_has_listener);
 674
 675 const struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
 676 EXPORT_SYMBOL_GPL(nf_nat_hook);
 677
 678 /* This does not belong here, but locally generated errors need it if connection
 679  * tracking in use: without this, connection may not be in hash table, and hence
 680  * manufactured ICMP or RST packets will not be associated with it.
 681  */
 682 void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
 683 {
 684         const struct nf_ct_hook *ct_hook;
 685
 686         if (skb->_nfct) {
 687                 rcu_read_lock();
 688                 ct_hook = rcu_dereference(nf_ct_hook);
 689                 if (ct_hook)
 690                         ct_hook->attach(new, skb);
 691                 rcu_read_unlock();
 692         }
 693 }
 694 EXPORT_SYMBOL(nf_ct_attach);
 695
 696 void nf_conntrack_destroy(struct nf_conntrack *nfct)
 697 {
 698         const struct nf_ct_hook *ct_hook;
 699
 700         rcu_read_lock();
 701         ct_hook = rcu_dereference(nf_ct_hook);
 702         if (ct_hook)
 703                 ct_hook->destroy(nfct);
 704         rcu_read_unlock();
 705
 706         WARN_ON(!ct_hook);
 707 }
 708 EXPORT_SYMBOL(nf_conntrack_destroy);
 709
 710 void nf_ct_set_closing(struct nf_conntrack *nfct)
 711 {
 712         const struct nf_ct_hook *ct_hook;
 713
 714         if (!nfct)
 715                 return;
 716
 717         rcu_read_lock();
 718         ct_hook = rcu_dereference(nf_ct_hook);
 719         if (ct_hook)
 720                 ct_hook->set_closing(nfct);
 721
 722         rcu_read_unlock();
 723 }
 724 EXPORT_SYMBOL_GPL(nf_ct_set_closing);
 725
 726 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
 727                          const struct sk_buff *skb)
 728 {
 729         const struct nf_ct_hook *ct_hook;
 730         bool ret = false;
 731
 732         rcu_read_lock();
 733         ct_hook = rcu_dereference(nf_ct_hook);
 734         if (ct_hook)
 735                 ret = ct_hook->get_tuple_skb(dst_tuple, skb);
 736         rcu_read_unlock();
 737         return ret;
 738 }
 739 EXPORT_SYMBOL(nf_ct_get_tuple_skb);
 740
 741 /* Built-in default zone used e.g. by modules. */
 742 const struct nf_conntrack_zone nf_ct_zone_dflt = {
 743         .id     = NF_CT_DEFAULT_ZONE_ID,
 744         .dir    = NF_CT_DEFAULT_ZONE_DIR,
 745 };
 746 EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
 747 #endif /* CONFIG_NF_CONNTRACK */
 748
 749 static void __net_init
 750 __netfilter_net_init(struct nf_hook_entries __rcu **e, int max)
 751 {
 752         int h;
 753
 754         for (h = 0; h < max; h++)
 755                 RCU_INIT_POINTER(e[h], NULL);
 756 }
 757
 758 static int __net_init netfilter_net_init(struct net *net)
 759 {
 760         __netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
 761         __netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
 762 #ifdef CONFIG_NETFILTER_FAMILY_ARP
 763         __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
 764 #endif
 765 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 766         __netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
 767 #endif
 768 #ifdef CONFIG_PROC_FS
 769         net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
 770                                                 net->proc_net);
 771         if (!net->nf.proc_netfilter) {
 772                 if (!net_eq(net, &init_net))
 773                         pr_err("cannot create netfilter proc entry");
 774
 775                 return -ENOMEM;
 776         }
 777 #endif
 778
 779         return 0;
 780 }
 781
 782 static void __net_exit netfilter_net_exit(struct net *net)
 783 {
 784         remove_proc_entry("netfilter", net->proc_net);
 785 }
 786
 787 static struct pernet_operations netfilter_net_ops = {
 788         .init = netfilter_net_init,
 789         .exit = netfilter_net_exit,
 790 };
 791
 792 int __init netfilter_init(void)
 793 {
 794         int ret;
 795
 796         ret = register_pernet_subsys(&netfilter_net_ops);
 797         if (ret < 0)
 798                 goto err;
 799
 800         ret = netfilter_log_init();
 801         if (ret < 0)
 802                 goto err_pernet;
 803
 804         return 0;
 805 err_pernet:
 806         unregister_pernet_subsys(&netfilter_net_ops);
 807 err:
 808         return ret;
 809 }