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
allocate_hook_entries_size(u16 num)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
__nf_hook_entries_free(struct rcu_head * h)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
nf_hook_entries_free(struct nf_hook_entries * e)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
accept_all(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)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 *
nf_hook_entries_grow(const struct nf_hook_entries * old,const struct nf_hook_ops * reg)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
hooks_validate(const struct nf_hook_entries * hooks)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
nf_hook_entries_insert_raw(struct nf_hook_entries __rcu ** pp,const struct nf_hook_ops * reg)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 */
__nf_hook_entries_try_shrink(struct nf_hook_entries * old,struct nf_hook_entries __rcu ** pp)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 **
nf_hook_entry_head(struct net * net,int pf,unsigned int hooknum,struct net_device * dev)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 #if IS_ENABLED(CONFIG_DECNET)
304 case NFPROTO_DECNET:
305 if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_decnet) <= hooknum))
306 return NULL;
307 return net->nf.hooks_decnet + hooknum;
308 #endif
309 default:
310 WARN_ON_ONCE(1);
311 return NULL;
312 }
313
314 #ifdef CONFIG_NETFILTER_INGRESS
315 if (hooknum == NF_NETDEV_INGRESS) {
316 if (dev && dev_net(dev) == net)
317 return &dev->nf_hooks_ingress;
318 }
319 #endif
320 #ifdef CONFIG_NETFILTER_EGRESS
321 if (hooknum == NF_NETDEV_EGRESS) {
322 if (dev && dev_net(dev) == net)
323 return &dev->nf_hooks_egress;
324 }
325 #endif
326 WARN_ON_ONCE(1);
327 return NULL;
328 }
329
nf_ingress_check(struct net * net,const struct nf_hook_ops * reg,int hooknum)330 static int nf_ingress_check(struct net *net, const struct nf_hook_ops *reg,
331 int hooknum)
332 {
333 #ifndef CONFIG_NETFILTER_INGRESS
334 if (reg->hooknum == hooknum)
335 return -EOPNOTSUPP;
336 #endif
337 if (reg->hooknum != hooknum ||
338 !reg->dev || dev_net(reg->dev) != net)
339 return -EINVAL;
340
341 return 0;
342 }
343
nf_ingress_hook(const struct nf_hook_ops * reg,int pf)344 static inline bool __maybe_unused nf_ingress_hook(const struct nf_hook_ops *reg,
345 int pf)
346 {
347 if ((pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS) ||
348 (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS))
349 return true;
350
351 return false;
352 }
353
nf_egress_hook(const struct nf_hook_ops * reg,int pf)354 static inline bool __maybe_unused nf_egress_hook(const struct nf_hook_ops *reg,
355 int pf)
356 {
357 return pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_EGRESS;
358 }
359
nf_static_key_inc(const struct nf_hook_ops * reg,int pf)360 static void nf_static_key_inc(const struct nf_hook_ops *reg, int pf)
361 {
362 #ifdef CONFIG_JUMP_LABEL
363 int hooknum;
364
365 if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
366 pf = NFPROTO_NETDEV;
367 hooknum = NF_NETDEV_INGRESS;
368 } else {
369 hooknum = reg->hooknum;
370 }
371 static_key_slow_inc(&nf_hooks_needed[pf][hooknum]);
372 #endif
373 }
374
nf_static_key_dec(const struct nf_hook_ops * reg,int pf)375 static void nf_static_key_dec(const struct nf_hook_ops *reg, int pf)
376 {
377 #ifdef CONFIG_JUMP_LABEL
378 int hooknum;
379
380 if (pf == NFPROTO_INET && reg->hooknum == NF_INET_INGRESS) {
381 pf = NFPROTO_NETDEV;
382 hooknum = NF_NETDEV_INGRESS;
383 } else {
384 hooknum = reg->hooknum;
385 }
386 static_key_slow_dec(&nf_hooks_needed[pf][hooknum]);
387 #endif
388 }
389
__nf_register_net_hook(struct net * net,int pf,const struct nf_hook_ops * reg)390 static int __nf_register_net_hook(struct net *net, int pf,
391 const struct nf_hook_ops *reg)
392 {
393 struct nf_hook_entries *p, *new_hooks;
394 struct nf_hook_entries __rcu **pp;
395 int err;
396
397 switch (pf) {
398 case NFPROTO_NETDEV:
399 #ifndef CONFIG_NETFILTER_INGRESS
400 if (reg->hooknum == NF_NETDEV_INGRESS)
401 return -EOPNOTSUPP;
402 #endif
403 #ifndef CONFIG_NETFILTER_EGRESS
404 if (reg->hooknum == NF_NETDEV_EGRESS)
405 return -EOPNOTSUPP;
406 #endif
407 if ((reg->hooknum != NF_NETDEV_INGRESS &&
408 reg->hooknum != NF_NETDEV_EGRESS) ||
409 !reg->dev || dev_net(reg->dev) != net)
410 return -EINVAL;
411 break;
412 case NFPROTO_INET:
413 if (reg->hooknum != NF_INET_INGRESS)
414 break;
415
416 err = nf_ingress_check(net, reg, NF_INET_INGRESS);
417 if (err < 0)
418 return err;
419 break;
420 }
421
422 pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
423 if (!pp)
424 return -EINVAL;
425
426 mutex_lock(&nf_hook_mutex);
427
428 p = nf_entry_dereference(*pp);
429 new_hooks = nf_hook_entries_grow(p, reg);
430
431 if (!IS_ERR(new_hooks))
432 rcu_assign_pointer(*pp, new_hooks);
433
434 mutex_unlock(&nf_hook_mutex);
435 if (IS_ERR(new_hooks))
436 return PTR_ERR(new_hooks);
437
438 hooks_validate(new_hooks);
439 #ifdef CONFIG_NETFILTER_INGRESS
440 if (nf_ingress_hook(reg, pf))
441 net_inc_ingress_queue();
442 #endif
443 #ifdef CONFIG_NETFILTER_EGRESS
444 if (nf_egress_hook(reg, pf))
445 net_inc_egress_queue();
446 #endif
447 nf_static_key_inc(reg, pf);
448
449 BUG_ON(p == new_hooks);
450 nf_hook_entries_free(p);
451 return 0;
452 }
453
454 /*
455 * nf_remove_net_hook - remove a hook from blob
456 *
457 * @oldp: current address of hook blob
458 * @unreg: hook to unregister
459 *
460 * This cannot fail, hook unregistration must always succeed.
461 * Therefore replace the to-be-removed hook with a dummy hook.
462 */
nf_remove_net_hook(struct nf_hook_entries * old,const struct nf_hook_ops * unreg)463 static bool nf_remove_net_hook(struct nf_hook_entries *old,
464 const struct nf_hook_ops *unreg)
465 {
466 struct nf_hook_ops **orig_ops;
467 unsigned int i;
468
469 orig_ops = nf_hook_entries_get_hook_ops(old);
470 for (i = 0; i < old->num_hook_entries; i++) {
471 if (orig_ops[i] != unreg)
472 continue;
473 WRITE_ONCE(old->hooks[i].hook, accept_all);
474 WRITE_ONCE(orig_ops[i], (void *)&dummy_ops);
475 return true;
476 }
477
478 return false;
479 }
480
__nf_unregister_net_hook(struct net * net,int pf,const struct nf_hook_ops * reg)481 static void __nf_unregister_net_hook(struct net *net, int pf,
482 const struct nf_hook_ops *reg)
483 {
484 struct nf_hook_entries __rcu **pp;
485 struct nf_hook_entries *p;
486
487 pp = nf_hook_entry_head(net, pf, reg->hooknum, reg->dev);
488 if (!pp)
489 return;
490
491 mutex_lock(&nf_hook_mutex);
492
493 p = nf_entry_dereference(*pp);
494 if (WARN_ON_ONCE(!p)) {
495 mutex_unlock(&nf_hook_mutex);
496 return;
497 }
498
499 if (nf_remove_net_hook(p, reg)) {
500 #ifdef CONFIG_NETFILTER_INGRESS
501 if (nf_ingress_hook(reg, pf))
502 net_dec_ingress_queue();
503 #endif
504 #ifdef CONFIG_NETFILTER_EGRESS
505 if (nf_egress_hook(reg, pf))
506 net_dec_egress_queue();
507 #endif
508 nf_static_key_dec(reg, pf);
509 } else {
510 WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
511 }
512
513 p = __nf_hook_entries_try_shrink(p, pp);
514 mutex_unlock(&nf_hook_mutex);
515 if (!p)
516 return;
517
518 nf_queue_nf_hook_drop(net);
519 nf_hook_entries_free(p);
520 }
521
nf_unregister_net_hook(struct net * net,const struct nf_hook_ops * reg)522 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
523 {
524 if (reg->pf == NFPROTO_INET) {
525 if (reg->hooknum == NF_INET_INGRESS) {
526 __nf_unregister_net_hook(net, NFPROTO_INET, reg);
527 } else {
528 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
529 __nf_unregister_net_hook(net, NFPROTO_IPV6, reg);
530 }
531 } else {
532 __nf_unregister_net_hook(net, reg->pf, reg);
533 }
534 }
535 EXPORT_SYMBOL(nf_unregister_net_hook);
536
nf_hook_entries_delete_raw(struct nf_hook_entries __rcu ** pp,const struct nf_hook_ops * reg)537 void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
538 const struct nf_hook_ops *reg)
539 {
540 struct nf_hook_entries *p;
541
542 p = rcu_dereference_raw(*pp);
543 if (nf_remove_net_hook(p, reg)) {
544 p = __nf_hook_entries_try_shrink(p, pp);
545 nf_hook_entries_free(p);
546 }
547 }
548 EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
549
nf_register_net_hook(struct net * net,const struct nf_hook_ops * reg)550 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
551 {
552 int err;
553
554 if (reg->pf == NFPROTO_INET) {
555 if (reg->hooknum == NF_INET_INGRESS) {
556 err = __nf_register_net_hook(net, NFPROTO_INET, reg);
557 if (err < 0)
558 return err;
559 } else {
560 err = __nf_register_net_hook(net, NFPROTO_IPV4, reg);
561 if (err < 0)
562 return err;
563
564 err = __nf_register_net_hook(net, NFPROTO_IPV6, reg);
565 if (err < 0) {
566 __nf_unregister_net_hook(net, NFPROTO_IPV4, reg);
567 return err;
568 }
569 }
570 } else {
571 err = __nf_register_net_hook(net, reg->pf, reg);
572 if (err < 0)
573 return err;
574 }
575
576 return 0;
577 }
578 EXPORT_SYMBOL(nf_register_net_hook);
579
nf_register_net_hooks(struct net * net,const struct nf_hook_ops * reg,unsigned int n)580 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
581 unsigned int n)
582 {
583 unsigned int i;
584 int err = 0;
585
586 for (i = 0; i < n; i++) {
587 err = nf_register_net_hook(net, ®[i]);
588 if (err)
589 goto err;
590 }
591 return err;
592
593 err:
594 if (i > 0)
595 nf_unregister_net_hooks(net, reg, i);
596 return err;
597 }
598 EXPORT_SYMBOL(nf_register_net_hooks);
599
nf_unregister_net_hooks(struct net * net,const struct nf_hook_ops * reg,unsigned int hookcount)600 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
601 unsigned int hookcount)
602 {
603 unsigned int i;
604
605 for (i = 0; i < hookcount; i++)
606 nf_unregister_net_hook(net, ®[i]);
607 }
608 EXPORT_SYMBOL(nf_unregister_net_hooks);
609
610 /* Returns 1 if okfn() needs to be executed by the caller,
611 * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */
nf_hook_slow(struct sk_buff * skb,struct nf_hook_state * state,const struct nf_hook_entries * e,unsigned int s)612 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
613 const struct nf_hook_entries *e, unsigned int s)
614 {
615 unsigned int verdict;
616 int ret;
617
618 for (; s < e->num_hook_entries; s++) {
619 verdict = nf_hook_entry_hookfn(&e->hooks[s], skb, state);
620 switch (verdict & NF_VERDICT_MASK) {
621 case NF_ACCEPT:
622 break;
623 case NF_DROP:
624 kfree_skb(skb);
625 ret = NF_DROP_GETERR(verdict);
626 if (ret == 0)
627 ret = -EPERM;
628 return ret;
629 case NF_QUEUE:
630 ret = nf_queue(skb, state, s, verdict);
631 if (ret == 1)
632 continue;
633 return ret;
634 default:
635 /* Implicit handling for NF_STOLEN, as well as any other
636 * non conventional verdicts.
637 */
638 return 0;
639 }
640 }
641
642 return 1;
643 }
644 EXPORT_SYMBOL(nf_hook_slow);
645
nf_hook_slow_list(struct list_head * head,struct nf_hook_state * state,const struct nf_hook_entries * e)646 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
647 const struct nf_hook_entries *e)
648 {
649 struct sk_buff *skb, *next;
650 struct list_head sublist;
651 int ret;
652
653 INIT_LIST_HEAD(&sublist);
654
655 list_for_each_entry_safe(skb, next, head, list) {
656 skb_list_del_init(skb);
657 ret = nf_hook_slow(skb, state, e, 0);
658 if (ret == 1)
659 list_add_tail(&skb->list, &sublist);
660 }
661 /* Put passed packets back on main list */
662 list_splice(&sublist, head);
663 }
664 EXPORT_SYMBOL(nf_hook_slow_list);
665
666 /* This needs to be compiled in any case to avoid dependencies between the
667 * nfnetlink_queue code and nf_conntrack.
668 */
669 struct nfnl_ct_hook __rcu *nfnl_ct_hook __read_mostly;
670 EXPORT_SYMBOL_GPL(nfnl_ct_hook);
671
672 struct nf_ct_hook __rcu *nf_ct_hook __read_mostly;
673 EXPORT_SYMBOL_GPL(nf_ct_hook);
674
675 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
676 /* This does not belong here, but locally generated errors need it if connection
677 tracking in use: without this, connection may not be in hash table, and hence
678 manufactured ICMP or RST packets will not be associated with it. */
679 void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *)
680 __rcu __read_mostly;
681 EXPORT_SYMBOL(ip_ct_attach);
682
683 struct nf_nat_hook __rcu *nf_nat_hook __read_mostly;
684 EXPORT_SYMBOL_GPL(nf_nat_hook);
685
nf_ct_attach(struct sk_buff * new,const struct sk_buff * skb)686 void nf_ct_attach(struct sk_buff *new, const struct sk_buff *skb)
687 {
688 void (*attach)(struct sk_buff *, const struct sk_buff *);
689
690 if (skb->_nfct) {
691 rcu_read_lock();
692 attach = rcu_dereference(ip_ct_attach);
693 if (attach)
694 attach(new, skb);
695 rcu_read_unlock();
696 }
697 }
698 EXPORT_SYMBOL(nf_ct_attach);
699
nf_conntrack_destroy(struct nf_conntrack * nfct)700 void nf_conntrack_destroy(struct nf_conntrack *nfct)
701 {
702 struct nf_ct_hook *ct_hook;
703
704 rcu_read_lock();
705 ct_hook = rcu_dereference(nf_ct_hook);
706 BUG_ON(ct_hook == NULL);
707 ct_hook->destroy(nfct);
708 rcu_read_unlock();
709 }
710 EXPORT_SYMBOL(nf_conntrack_destroy);
711
nf_ct_get_tuple_skb(struct nf_conntrack_tuple * dst_tuple,const struct sk_buff * skb)712 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
713 const struct sk_buff *skb)
714 {
715 struct nf_ct_hook *ct_hook;
716 bool ret = false;
717
718 rcu_read_lock();
719 ct_hook = rcu_dereference(nf_ct_hook);
720 if (ct_hook)
721 ret = ct_hook->get_tuple_skb(dst_tuple, skb);
722 rcu_read_unlock();
723 return ret;
724 }
725 EXPORT_SYMBOL(nf_ct_get_tuple_skb);
726
727 /* Built-in default zone used e.g. by modules. */
728 const struct nf_conntrack_zone nf_ct_zone_dflt = {
729 .id = NF_CT_DEFAULT_ZONE_ID,
730 .dir = NF_CT_DEFAULT_ZONE_DIR,
731 };
732 EXPORT_SYMBOL_GPL(nf_ct_zone_dflt);
733 #endif /* CONFIG_NF_CONNTRACK */
734
735 static void __net_init
__netfilter_net_init(struct nf_hook_entries __rcu ** e,int max)736 __netfilter_net_init(struct nf_hook_entries __rcu **e, int max)
737 {
738 int h;
739
740 for (h = 0; h < max; h++)
741 RCU_INIT_POINTER(e[h], NULL);
742 }
743
netfilter_net_init(struct net * net)744 static int __net_init netfilter_net_init(struct net *net)
745 {
746 __netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
747 __netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
748 #ifdef CONFIG_NETFILTER_FAMILY_ARP
749 __netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
750 #endif
751 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
752 __netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
753 #endif
754 #if IS_ENABLED(CONFIG_DECNET)
755 __netfilter_net_init(net->nf.hooks_decnet, ARRAY_SIZE(net->nf.hooks_decnet));
756 #endif
757
758 #ifdef CONFIG_PROC_FS
759 net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
760 net->proc_net);
761 if (!net->nf.proc_netfilter) {
762 if (!net_eq(net, &init_net))
763 pr_err("cannot create netfilter proc entry");
764
765 return -ENOMEM;
766 }
767 #endif
768
769 return 0;
770 }
771
netfilter_net_exit(struct net * net)772 static void __net_exit netfilter_net_exit(struct net *net)
773 {
774 remove_proc_entry("netfilter", net->proc_net);
775 }
776
777 static struct pernet_operations netfilter_net_ops = {
778 .init = netfilter_net_init,
779 .exit = netfilter_net_exit,
780 };
781
netfilter_init(void)782 int __init netfilter_init(void)
783 {
784 int ret;
785
786 ret = register_pernet_subsys(&netfilter_net_ops);
787 if (ret < 0)
788 goto err;
789
790 ret = netfilter_log_init();
791 if (ret < 0)
792 goto err_pernet;
793
794 return 0;
795 err_pernet:
796 unregister_pernet_subsys(&netfilter_net_ops);
797 err:
798 return ret;
799 }
800