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11#include <linux/module.h>
12#include <linux/types.h>
13#include <linux/timer.h>
14#include <linux/skbuff.h>
15#include <net/checksum.h>
16#include <net/icmp.h>
17#include <net/ip.h>
18#include <net/tcp.h>
19#include <linux/icmp.h>
20#include <linux/udp.h>
21#include <linux/jhash.h>
22
23#include <linux/netfilter_ipv4.h>
24#include <net/netfilter/nf_conntrack.h>
25#include <net/netfilter/nf_conntrack_core.h>
26#include <net/netfilter/nf_nat.h>
27#include <net/netfilter/nf_nat_protocol.h>
28#include <net/netfilter/nf_nat_core.h>
29#include <net/netfilter/nf_nat_helper.h>
30#include <net/netfilter/nf_conntrack_helper.h>
31#include <net/netfilter/nf_conntrack_l3proto.h>
32#include <net/netfilter/nf_conntrack_l4proto.h>
33
34static DEFINE_SPINLOCK(nf_nat_lock);
35
36static struct nf_conntrack_l3proto *l3proto __read_mostly;
37
38
39static unsigned int nf_nat_htable_size __read_mostly;
40
41#define MAX_IP_NAT_PROTO 256
42static const struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO]
43 __read_mostly;
44
45static inline const struct nf_nat_protocol *
46__nf_nat_proto_find(u_int8_t protonum)
47{
48 return rcu_dereference(nf_nat_protos[protonum]);
49}
50
51const struct nf_nat_protocol *
52nf_nat_proto_find_get(u_int8_t protonum)
53{
54 const struct nf_nat_protocol *p;
55
56 rcu_read_lock();
57 p = __nf_nat_proto_find(protonum);
58 if (!try_module_get(p->me))
59 p = &nf_nat_unknown_protocol;
60 rcu_read_unlock();
61
62 return p;
63}
64EXPORT_SYMBOL_GPL(nf_nat_proto_find_get);
65
66void
67nf_nat_proto_put(const struct nf_nat_protocol *p)
68{
69 module_put(p->me);
70}
71EXPORT_SYMBOL_GPL(nf_nat_proto_put);
72
73
74static inline unsigned int
75hash_by_src(const struct nf_conntrack_tuple *tuple)
76{
77 unsigned int hash;
78
79
80 hash = jhash_3words((__force u32)tuple->src.u3.ip,
81 (__force u32)tuple->src.u.all,
82 tuple->dst.protonum, 0);
83 return ((u64)hash * nf_nat_htable_size) >> 32;
84}
85
86
87int
88nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
89 const struct nf_conn *ignored_conntrack)
90{
91
92
93
94
95
96 struct nf_conntrack_tuple reply;
97
98 nf_ct_invert_tuplepr(&reply, tuple);
99 return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
100}
101EXPORT_SYMBOL(nf_nat_used_tuple);
102
103
104
105static int
106in_range(const struct nf_conntrack_tuple *tuple,
107 const struct nf_nat_range *range)
108{
109 const struct nf_nat_protocol *proto;
110 int ret = 0;
111
112
113
114 if (range->flags & IP_NAT_RANGE_MAP_IPS) {
115 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
116 ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
117 return 0;
118 }
119
120 rcu_read_lock();
121 proto = __nf_nat_proto_find(tuple->dst.protonum);
122 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
123 proto->in_range(tuple, IP_NAT_MANIP_SRC,
124 &range->min, &range->max))
125 ret = 1;
126 rcu_read_unlock();
127
128 return ret;
129}
130
131static inline int
132same_src(const struct nf_conn *ct,
133 const struct nf_conntrack_tuple *tuple)
134{
135 const struct nf_conntrack_tuple *t;
136
137 t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
138 return (t->dst.protonum == tuple->dst.protonum &&
139 t->src.u3.ip == tuple->src.u3.ip &&
140 t->src.u.all == tuple->src.u.all);
141}
142
143
144static int
145find_appropriate_src(struct net *net,
146 const struct nf_conntrack_tuple *tuple,
147 struct nf_conntrack_tuple *result,
148 const struct nf_nat_range *range)
149{
150 unsigned int h = hash_by_src(tuple);
151 const struct nf_conn_nat *nat;
152 const struct nf_conn *ct;
153 const struct hlist_node *n;
154
155 rcu_read_lock();
156 hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) {
157 ct = nat->ct;
158 if (same_src(ct, tuple)) {
159
160 nf_ct_invert_tuplepr(result,
161 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
162 result->dst = tuple->dst;
163
164 if (in_range(result, range)) {
165 rcu_read_unlock();
166 return 1;
167 }
168 }
169 }
170 rcu_read_unlock();
171 return 0;
172}
173
174
175
176
177
178
179
180static void
181find_best_ips_proto(struct nf_conntrack_tuple *tuple,
182 const struct nf_nat_range *range,
183 const struct nf_conn *ct,
184 enum nf_nat_manip_type maniptype)
185{
186 __be32 *var_ipp;
187
188 u_int32_t minip, maxip, j;
189
190
191 if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
192 return;
193
194 if (maniptype == IP_NAT_MANIP_SRC)
195 var_ipp = &tuple->src.u3.ip;
196 else
197 var_ipp = &tuple->dst.u3.ip;
198
199
200 if (range->min_ip == range->max_ip) {
201 *var_ipp = range->min_ip;
202 return;
203 }
204
205
206
207
208
209
210
211 minip = ntohl(range->min_ip);
212 maxip = ntohl(range->max_ip);
213 j = jhash_2words((__force u32)tuple->src.u3.ip,
214 range->flags & IP_NAT_RANGE_PERSISTENT ?
215 0 : (__force u32)tuple->dst.u3.ip, 0);
216 j = ((u64)j * (maxip - minip + 1)) >> 32;
217 *var_ipp = htonl(minip + j);
218}
219
220
221
222
223
224
225
226static void
227get_unique_tuple(struct nf_conntrack_tuple *tuple,
228 const struct nf_conntrack_tuple *orig_tuple,
229 const struct nf_nat_range *range,
230 struct nf_conn *ct,
231 enum nf_nat_manip_type maniptype)
232{
233 struct net *net = nf_ct_net(ct);
234 const struct nf_nat_protocol *proto;
235
236
237
238
239
240
241
242
243 if (maniptype == IP_NAT_MANIP_SRC &&
244 !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
245 if (find_appropriate_src(net, orig_tuple, tuple, range)) {
246 pr_debug("get_unique_tuple: Found current src map\n");
247 if (!nf_nat_used_tuple(tuple, ct))
248 return;
249 }
250 }
251
252
253
254 *tuple = *orig_tuple;
255 find_best_ips_proto(tuple, range, ct, maniptype);
256
257
258
259
260 rcu_read_lock();
261 proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
262
263
264 if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
265 proto->unique_tuple(tuple, range, maniptype, ct);
266 goto out;
267 }
268
269
270 if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
271 proto->in_range(tuple, maniptype, &range->min, &range->max)) &&
272 !nf_nat_used_tuple(tuple, ct))
273 goto out;
274
275
276 proto->unique_tuple(tuple, range, maniptype, ct);
277out:
278 rcu_read_unlock();
279}
280
281unsigned int
282nf_nat_setup_info(struct nf_conn *ct,
283 const struct nf_nat_range *range,
284 enum nf_nat_manip_type maniptype)
285{
286 struct net *net = nf_ct_net(ct);
287 struct nf_conntrack_tuple curr_tuple, new_tuple;
288 struct nf_conn_nat *nat;
289 int have_to_hash = !(ct->status & IPS_NAT_DONE_MASK);
290
291
292 nat = nfct_nat(ct);
293 if (!nat) {
294 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
295 if (nat == NULL) {
296 pr_debug("failed to add NAT extension\n");
297 return NF_ACCEPT;
298 }
299 }
300
301 NF_CT_ASSERT(maniptype == IP_NAT_MANIP_SRC ||
302 maniptype == IP_NAT_MANIP_DST);
303 BUG_ON(nf_nat_initialized(ct, maniptype));
304
305
306
307
308
309
310 nf_ct_invert_tuplepr(&curr_tuple,
311 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
312
313 get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
314
315 if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
316 struct nf_conntrack_tuple reply;
317
318
319 nf_ct_invert_tuplepr(&reply, &new_tuple);
320 nf_conntrack_alter_reply(ct, &reply);
321
322
323 if (maniptype == IP_NAT_MANIP_SRC)
324 ct->status |= IPS_SRC_NAT;
325 else
326 ct->status |= IPS_DST_NAT;
327 }
328
329
330 if (have_to_hash) {
331 unsigned int srchash;
332
333 srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
334 spin_lock_bh(&nf_nat_lock);
335
336 nat = nfct_nat(ct);
337 nat->ct = ct;
338 hlist_add_head_rcu(&nat->bysource,
339 &net->ipv4.nat_bysource[srchash]);
340 spin_unlock_bh(&nf_nat_lock);
341 }
342
343
344 if (maniptype == IP_NAT_MANIP_DST)
345 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
346 else
347 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
348
349 return NF_ACCEPT;
350}
351EXPORT_SYMBOL(nf_nat_setup_info);
352
353
354static bool
355manip_pkt(u_int16_t proto,
356 struct sk_buff *skb,
357 unsigned int iphdroff,
358 const struct nf_conntrack_tuple *target,
359 enum nf_nat_manip_type maniptype)
360{
361 struct iphdr *iph;
362 const struct nf_nat_protocol *p;
363
364 if (!skb_make_writable(skb, iphdroff + sizeof(*iph)))
365 return false;
366
367 iph = (void *)skb->data + iphdroff;
368
369
370
371
372 p = __nf_nat_proto_find(proto);
373 if (!p->manip_pkt(skb, iphdroff, target, maniptype))
374 return false;
375
376 iph = (void *)skb->data + iphdroff;
377
378 if (maniptype == IP_NAT_MANIP_SRC) {
379 csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
380 iph->saddr = target->src.u3.ip;
381 } else {
382 csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
383 iph->daddr = target->dst.u3.ip;
384 }
385 return true;
386}
387
388
389unsigned int nf_nat_packet(struct nf_conn *ct,
390 enum ip_conntrack_info ctinfo,
391 unsigned int hooknum,
392 struct sk_buff *skb)
393{
394 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
395 unsigned long statusbit;
396 enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
397
398 if (mtype == IP_NAT_MANIP_SRC)
399 statusbit = IPS_SRC_NAT;
400 else
401 statusbit = IPS_DST_NAT;
402
403
404 if (dir == IP_CT_DIR_REPLY)
405 statusbit ^= IPS_NAT_MASK;
406
407
408 if (ct->status & statusbit) {
409 struct nf_conntrack_tuple target;
410
411
412 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
413
414 if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype))
415 return NF_DROP;
416 }
417 return NF_ACCEPT;
418}
419EXPORT_SYMBOL_GPL(nf_nat_packet);
420
421
422int nf_nat_icmp_reply_translation(struct nf_conn *ct,
423 enum ip_conntrack_info ctinfo,
424 unsigned int hooknum,
425 struct sk_buff *skb)
426{
427 struct {
428 struct icmphdr icmp;
429 struct iphdr ip;
430 } *inside;
431 const struct nf_conntrack_l4proto *l4proto;
432 struct nf_conntrack_tuple inner, target;
433 int hdrlen = ip_hdrlen(skb);
434 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
435 unsigned long statusbit;
436 enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
437
438 if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
439 return 0;
440
441 inside = (void *)skb->data + ip_hdrlen(skb);
442
443
444
445 if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
446 return 0;
447
448
449 NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED ||
450 skb->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
451
452
453
454
455 if (inside->icmp.type == ICMP_REDIRECT) {
456
457 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
458 return 0;
459
460 if (ct->status & IPS_NAT_MASK)
461 return 0;
462 }
463
464 pr_debug("icmp_reply_translation: translating error %p manip %u "
465 "dir %s\n", skb, manip,
466 dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
467
468
469 l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
470
471 if (!nf_ct_get_tuple(skb,
472 ip_hdrlen(skb) + sizeof(struct icmphdr),
473 (ip_hdrlen(skb) +
474 sizeof(struct icmphdr) + inside->ip.ihl * 4),
475 (u_int16_t)AF_INET,
476 inside->ip.protocol,
477 &inner, l3proto, l4proto))
478 return 0;
479
480
481
482
483
484
485 if (!manip_pkt(inside->ip.protocol, skb,
486 ip_hdrlen(skb) + sizeof(inside->icmp),
487 &ct->tuplehash[!dir].tuple,
488 !manip))
489 return 0;
490
491 if (skb->ip_summed != CHECKSUM_PARTIAL) {
492
493 inside = (void *)skb->data + ip_hdrlen(skb);
494 inside->icmp.checksum = 0;
495 inside->icmp.checksum =
496 csum_fold(skb_checksum(skb, hdrlen,
497 skb->len - hdrlen, 0));
498 }
499
500
501
502 if (manip == IP_NAT_MANIP_SRC)
503 statusbit = IPS_SRC_NAT;
504 else
505 statusbit = IPS_DST_NAT;
506
507
508 if (dir == IP_CT_DIR_REPLY)
509 statusbit ^= IPS_NAT_MASK;
510
511 if (ct->status & statusbit) {
512 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
513 if (!manip_pkt(0, skb, 0, &target, manip))
514 return 0;
515 }
516
517 return 1;
518}
519EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
520
521
522int nf_nat_protocol_register(const struct nf_nat_protocol *proto)
523{
524 int ret = 0;
525
526 spin_lock_bh(&nf_nat_lock);
527 if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
528 ret = -EBUSY;
529 goto out;
530 }
531 rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
532 out:
533 spin_unlock_bh(&nf_nat_lock);
534 return ret;
535}
536EXPORT_SYMBOL(nf_nat_protocol_register);
537
538
539void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto)
540{
541 spin_lock_bh(&nf_nat_lock);
542 rcu_assign_pointer(nf_nat_protos[proto->protonum],
543 &nf_nat_unknown_protocol);
544 spin_unlock_bh(&nf_nat_lock);
545 synchronize_rcu();
546}
547EXPORT_SYMBOL(nf_nat_protocol_unregister);
548
549
550static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
551{
552 struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
553
554 if (nat == NULL || nat->ct == NULL)
555 return;
556
557 NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK);
558
559 spin_lock_bh(&nf_nat_lock);
560 hlist_del_rcu(&nat->bysource);
561 spin_unlock_bh(&nf_nat_lock);
562}
563
564static void nf_nat_move_storage(void *new, void *old)
565{
566 struct nf_conn_nat *new_nat = new;
567 struct nf_conn_nat *old_nat = old;
568 struct nf_conn *ct = old_nat->ct;
569
570 if (!ct || !(ct->status & IPS_NAT_DONE_MASK))
571 return;
572
573 spin_lock_bh(&nf_nat_lock);
574 new_nat->ct = ct;
575 hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
576 spin_unlock_bh(&nf_nat_lock);
577}
578
579static struct nf_ct_ext_type nat_extend __read_mostly = {
580 .len = sizeof(struct nf_conn_nat),
581 .align = __alignof__(struct nf_conn_nat),
582 .destroy = nf_nat_cleanup_conntrack,
583 .move = nf_nat_move_storage,
584 .id = NF_CT_EXT_NAT,
585 .flags = NF_CT_EXT_F_PREALLOC,
586};
587
588#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
589
590#include <linux/netfilter/nfnetlink.h>
591#include <linux/netfilter/nfnetlink_conntrack.h>
592
593static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
594 [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
595 [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
596};
597
598static int nfnetlink_parse_nat_proto(struct nlattr *attr,
599 const struct nf_conn *ct,
600 struct nf_nat_range *range)
601{
602 struct nlattr *tb[CTA_PROTONAT_MAX+1];
603 const struct nf_nat_protocol *npt;
604 int err;
605
606 err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
607 if (err < 0)
608 return err;
609
610 npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
611 if (npt->nlattr_to_range)
612 err = npt->nlattr_to_range(tb, range);
613 nf_nat_proto_put(npt);
614 return err;
615}
616
617static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
618 [CTA_NAT_MINIP] = { .type = NLA_U32 },
619 [CTA_NAT_MAXIP] = { .type = NLA_U32 },
620};
621
622static int
623nfnetlink_parse_nat(const struct nlattr *nat,
624 const struct nf_conn *ct, struct nf_nat_range *range)
625{
626 struct nlattr *tb[CTA_NAT_MAX+1];
627 int err;
628
629 memset(range, 0, sizeof(*range));
630
631 err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
632 if (err < 0)
633 return err;
634
635 if (tb[CTA_NAT_MINIP])
636 range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]);
637
638 if (!tb[CTA_NAT_MAXIP])
639 range->max_ip = range->min_ip;
640 else
641 range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]);
642
643 if (range->min_ip)
644 range->flags |= IP_NAT_RANGE_MAP_IPS;
645
646 if (!tb[CTA_NAT_PROTO])
647 return 0;
648
649 err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
650 if (err < 0)
651 return err;
652
653 return 0;
654}
655
656static int
657nfnetlink_parse_nat_setup(struct nf_conn *ct,
658 enum nf_nat_manip_type manip,
659 const struct nlattr *attr)
660{
661 struct nf_nat_range range;
662
663 if (nfnetlink_parse_nat(attr, ct, &range) < 0)
664 return -EINVAL;
665 if (nf_nat_initialized(ct, manip))
666 return -EEXIST;
667
668 return nf_nat_setup_info(ct, &range, manip);
669}
670#else
671static int
672nfnetlink_parse_nat_setup(struct nf_conn *ct,
673 enum nf_nat_manip_type manip,
674 const struct nlattr *attr)
675{
676 return -EOPNOTSUPP;
677}
678#endif
679
680static int __net_init nf_nat_net_init(struct net *net)
681{
682 net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&nf_nat_htable_size,
683 &net->ipv4.nat_vmalloced, 0);
684 if (!net->ipv4.nat_bysource)
685 return -ENOMEM;
686 return 0;
687}
688
689
690static int clean_nat(struct nf_conn *i, void *data)
691{
692 struct nf_conn_nat *nat = nfct_nat(i);
693
694 if (!nat)
695 return 0;
696 memset(nat, 0, sizeof(*nat));
697 i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
698 return 0;
699}
700
701static void __net_exit nf_nat_net_exit(struct net *net)
702{
703 nf_ct_iterate_cleanup(net, &clean_nat, NULL);
704 synchronize_rcu();
705 nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_vmalloced,
706 nf_nat_htable_size);
707}
708
709static struct pernet_operations nf_nat_net_ops = {
710 .init = nf_nat_net_init,
711 .exit = nf_nat_net_exit,
712};
713
714static int __init nf_nat_init(void)
715{
716 size_t i;
717 int ret;
718
719 need_ipv4_conntrack();
720
721 ret = nf_ct_extend_register(&nat_extend);
722 if (ret < 0) {
723 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
724 return ret;
725 }
726
727
728 nf_nat_htable_size = nf_conntrack_htable_size;
729
730 ret = register_pernet_subsys(&nf_nat_net_ops);
731 if (ret < 0)
732 goto cleanup_extend;
733
734
735 spin_lock_bh(&nf_nat_lock);
736 for (i = 0; i < MAX_IP_NAT_PROTO; i++)
737 rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
738 rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
739 rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
740 rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
741 spin_unlock_bh(&nf_nat_lock);
742
743
744 nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK;
745
746 l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
747
748 BUG_ON(nf_nat_seq_adjust_hook != NULL);
749 rcu_assign_pointer(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
750 BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
751 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook,
752 nfnetlink_parse_nat_setup);
753 BUG_ON(nf_ct_nat_offset != NULL);
754 rcu_assign_pointer(nf_ct_nat_offset, nf_nat_get_offset);
755 return 0;
756
757 cleanup_extend:
758 nf_ct_extend_unregister(&nat_extend);
759 return ret;
760}
761
762static void __exit nf_nat_cleanup(void)
763{
764 unregister_pernet_subsys(&nf_nat_net_ops);
765 nf_ct_l3proto_put(l3proto);
766 nf_ct_extend_unregister(&nat_extend);
767 rcu_assign_pointer(nf_nat_seq_adjust_hook, NULL);
768 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, NULL);
769 rcu_assign_pointer(nf_ct_nat_offset, NULL);
770 synchronize_net();
771}
772
773MODULE_LICENSE("GPL");
774MODULE_ALIAS("nf-nat-ipv4");
775
776module_init(nf_nat_init);
777module_exit(nf_nat_cleanup);
778