1 /* NAT for netfilter; shared with compatibility layer. */
3 /* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/timer.h>
14 #include <linux/skbuff.h>
15 #include <linux/gfp.h>
16 #include <net/checksum.h>
19 #include <net/tcp.h> /* For tcp_prot in getorigdst */
20 #include <linux/icmp.h>
21 #include <linux/udp.h>
22 #include <linux/jhash.h>
24 #include <linux/netfilter_ipv4.h>
25 #include <net/netfilter/nf_conntrack.h>
26 #include <net/netfilter/nf_conntrack_core.h>
27 #include <net/netfilter/nf_nat.h>
28 #include <net/netfilter/nf_nat_protocol.h>
29 #include <net/netfilter/nf_nat_core.h>
30 #include <net/netfilter/nf_nat_helper.h>
31 #include <net/netfilter/nf_conntrack_helper.h>
32 #include <net/netfilter/nf_conntrack_l3proto.h>
33 #include <net/netfilter/nf_conntrack_l4proto.h>
34 #include <net/netfilter/nf_conntrack_zones.h>
36 static DEFINE_SPINLOCK(nf_nat_lock);
38 static struct nf_conntrack_l3proto *l3proto __read_mostly;
40 #define MAX_IP_NAT_PROTO 256
41 static const struct nf_nat_protocol __rcu *nf_nat_protos[MAX_IP_NAT_PROTO]
44 static inline const struct nf_nat_protocol *
45 __nf_nat_proto_find(u_int8_t protonum)
47 return rcu_dereference(nf_nat_protos[protonum]);
50 static const struct nf_nat_protocol *
51 nf_nat_proto_find_get(u_int8_t protonum)
53 const struct nf_nat_protocol *p;
56 p = __nf_nat_proto_find(protonum);
57 if (!try_module_get(p->me))
58 p = &nf_nat_unknown_protocol;
65 nf_nat_proto_put(const struct nf_nat_protocol *p)
70 /* We keep an extra hash for each conntrack, for fast searching. */
71 static inline unsigned int
72 hash_by_src(const struct net *net, u16 zone,
73 const struct nf_conntrack_tuple *tuple)
77 /* Original src, to ensure we map it consistently if poss. */
78 hash = jhash_3words((__force u32)tuple->src.u3.ip,
79 (__force u32)tuple->src.u.all ^ zone,
80 tuple->dst.protonum, 0);
81 return ((u64)hash * net->ipv4.nat_htable_size) >> 32;
84 /* Is this tuple already taken? (not by us) */
86 nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
87 const struct nf_conn *ignored_conntrack)
89 /* Conntrack tracking doesn't keep track of outgoing tuples; only
90 incoming ones. NAT means they don't have a fixed mapping,
91 so we invert the tuple and look for the incoming reply.
93 We could keep a separate hash if this proves too slow. */
94 struct nf_conntrack_tuple reply;
96 nf_ct_invert_tuplepr(&reply, tuple);
97 return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
99 EXPORT_SYMBOL(nf_nat_used_tuple);
101 /* If we source map this tuple so reply looks like reply_tuple, will
102 * that meet the constraints of range. */
104 in_range(const struct nf_conntrack_tuple *tuple,
105 const struct nf_nat_range *range)
107 const struct nf_nat_protocol *proto;
110 /* If we are supposed to map IPs, then we must be in the
111 range specified, otherwise let this drag us onto a new src IP. */
112 if (range->flags & IP_NAT_RANGE_MAP_IPS) {
113 if (ntohl(tuple->src.u3.ip) < ntohl(range->min_ip) ||
114 ntohl(tuple->src.u3.ip) > ntohl(range->max_ip))
119 proto = __nf_nat_proto_find(tuple->dst.protonum);
120 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
121 proto->in_range(tuple, IP_NAT_MANIP_SRC,
122 &range->min, &range->max))
130 same_src(const struct nf_conn *ct,
131 const struct nf_conntrack_tuple *tuple)
133 const struct nf_conntrack_tuple *t;
135 t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
136 return (t->dst.protonum == tuple->dst.protonum &&
137 t->src.u3.ip == tuple->src.u3.ip &&
138 t->src.u.all == tuple->src.u.all);
141 /* Only called for SRC manip */
143 find_appropriate_src(struct net *net, u16 zone,
144 const struct nf_conntrack_tuple *tuple,
145 struct nf_conntrack_tuple *result,
146 const struct nf_nat_range *range)
148 unsigned int h = hash_by_src(net, zone, tuple);
149 const struct nf_conn_nat *nat;
150 const struct nf_conn *ct;
151 const struct hlist_node *n;
154 hlist_for_each_entry_rcu(nat, n, &net->ipv4.nat_bysource[h], bysource) {
156 if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
157 /* Copy source part from reply tuple. */
158 nf_ct_invert_tuplepr(result,
159 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
160 result->dst = tuple->dst;
162 if (in_range(result, range)) {
172 /* For [FUTURE] fragmentation handling, we want the least-used
173 src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
174 if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
175 1-65535, we don't do pro-rata allocation based on ports; we choose
176 the ip with the lowest src-ip/dst-ip/proto usage.
179 find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
180 const struct nf_nat_range *range,
181 const struct nf_conn *ct,
182 enum nf_nat_manip_type maniptype)
186 u_int32_t minip, maxip, j;
188 /* No IP mapping? Do nothing. */
189 if (!(range->flags & IP_NAT_RANGE_MAP_IPS))
192 if (maniptype == IP_NAT_MANIP_SRC)
193 var_ipp = &tuple->src.u3.ip;
195 var_ipp = &tuple->dst.u3.ip;
197 /* Fast path: only one choice. */
198 if (range->min_ip == range->max_ip) {
199 *var_ipp = range->min_ip;
203 /* Hashing source and destination IPs gives a fairly even
204 * spread in practice (if there are a small number of IPs
205 * involved, there usually aren't that many connections
206 * anyway). The consistency means that servers see the same
207 * client coming from the same IP (some Internet Banking sites
208 * like this), even across reboots. */
209 minip = ntohl(range->min_ip);
210 maxip = ntohl(range->max_ip);
211 j = jhash_2words((__force u32)tuple->src.u3.ip,
212 range->flags & IP_NAT_RANGE_PERSISTENT ?
213 0 : (__force u32)tuple->dst.u3.ip ^ zone, 0);
214 j = ((u64)j * (maxip - minip + 1)) >> 32;
215 *var_ipp = htonl(minip + j);
218 /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
219 * we change the source to map into the range. For NF_INET_PRE_ROUTING
220 * and NF_INET_LOCAL_OUT, we change the destination to map into the
221 * range. It might not be possible to get a unique tuple, but we try.
222 * At worst (or if we race), we will end up with a final duplicate in
223 * __ip_conntrack_confirm and drop the packet. */
225 get_unique_tuple(struct nf_conntrack_tuple *tuple,
226 const struct nf_conntrack_tuple *orig_tuple,
227 const struct nf_nat_range *range,
229 enum nf_nat_manip_type maniptype)
231 struct net *net = nf_ct_net(ct);
232 const struct nf_nat_protocol *proto;
233 u16 zone = nf_ct_zone(ct);
235 /* 1) If this srcip/proto/src-proto-part is currently mapped,
236 and that same mapping gives a unique tuple within the given
239 This is only required for source (ie. NAT/masq) mappings.
240 So far, we don't do local source mappings, so multiple
241 manips not an issue. */
242 if (maniptype == IP_NAT_MANIP_SRC &&
243 !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
244 if (find_appropriate_src(net, zone, orig_tuple, tuple, range)) {
245 pr_debug("get_unique_tuple: Found current src map\n");
246 if (!nf_nat_used_tuple(tuple, ct))
251 /* 2) Select the least-used IP/proto combination in the given
253 *tuple = *orig_tuple;
254 find_best_ips_proto(zone, tuple, range, ct, maniptype);
256 /* 3) The per-protocol part of the manip is made to map into
257 the range to make a unique tuple. */
260 proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
262 /* Only bother mapping if it's not already in range and unique */
263 if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
264 if (range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
265 if (proto->in_range(tuple, maniptype, &range->min,
267 (range->min.all == range->max.all ||
268 !nf_nat_used_tuple(tuple, ct)))
270 } else if (!nf_nat_used_tuple(tuple, ct)) {
275 /* Last change: get protocol to try to obtain unique tuple. */
276 proto->unique_tuple(tuple, range, maniptype, ct);
282 nf_nat_setup_info(struct nf_conn *ct,
283 const struct nf_nat_range *range,
284 enum nf_nat_manip_type maniptype)
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);
291 /* nat helper or nfctnetlink also setup binding */
294 nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
296 pr_debug("failed to add NAT extension\n");
301 NF_CT_ASSERT(maniptype == IP_NAT_MANIP_SRC ||
302 maniptype == IP_NAT_MANIP_DST);
303 BUG_ON(nf_nat_initialized(ct, maniptype));
305 /* What we've got will look like inverse of reply. Normally
306 this is what is in the conntrack, except for prior
307 manipulations (future optimization: if num_manips == 0,
309 conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple) */
310 nf_ct_invert_tuplepr(&curr_tuple,
311 &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
313 get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
315 if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
316 struct nf_conntrack_tuple reply;
318 /* Alter conntrack table so will recognize replies. */
319 nf_ct_invert_tuplepr(&reply, &new_tuple);
320 nf_conntrack_alter_reply(ct, &reply);
322 /* Non-atomic: we own this at the moment. */
323 if (maniptype == IP_NAT_MANIP_SRC)
324 ct->status |= IPS_SRC_NAT;
326 ct->status |= IPS_DST_NAT;
329 /* Place in source hash if this is the first time. */
331 unsigned int srchash;
333 srchash = hash_by_src(net, nf_ct_zone(ct),
334 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
335 spin_lock_bh(&nf_nat_lock);
336 /* nf_conntrack_alter_reply might re-allocate exntension aera */
339 hlist_add_head_rcu(&nat->bysource,
340 &net->ipv4.nat_bysource[srchash]);
341 spin_unlock_bh(&nf_nat_lock);
345 if (maniptype == IP_NAT_MANIP_DST)
346 set_bit(IPS_DST_NAT_DONE_BIT, &ct->status);
348 set_bit(IPS_SRC_NAT_DONE_BIT, &ct->status);
352 EXPORT_SYMBOL(nf_nat_setup_info);
354 /* Returns true if succeeded. */
356 manip_pkt(u_int16_t proto,
358 unsigned int iphdroff,
359 const struct nf_conntrack_tuple *target,
360 enum nf_nat_manip_type maniptype)
363 const struct nf_nat_protocol *p;
365 if (!skb_make_writable(skb, iphdroff + sizeof(*iph)))
368 iph = (void *)skb->data + iphdroff;
370 /* Manipulate protcol part. */
372 /* rcu_read_lock()ed by nf_hook_slow */
373 p = __nf_nat_proto_find(proto);
374 if (!p->manip_pkt(skb, iphdroff, target, maniptype))
377 iph = (void *)skb->data + iphdroff;
379 if (maniptype == IP_NAT_MANIP_SRC) {
380 csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
381 iph->saddr = target->src.u3.ip;
383 csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
384 iph->daddr = target->dst.u3.ip;
389 /* Do packet manipulations according to nf_nat_setup_info. */
390 unsigned int nf_nat_packet(struct nf_conn *ct,
391 enum ip_conntrack_info ctinfo,
392 unsigned int hooknum,
395 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
396 unsigned long statusbit;
397 enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
399 if (mtype == IP_NAT_MANIP_SRC)
400 statusbit = IPS_SRC_NAT;
402 statusbit = IPS_DST_NAT;
404 /* Invert if this is reply dir. */
405 if (dir == IP_CT_DIR_REPLY)
406 statusbit ^= IPS_NAT_MASK;
408 /* Non-atomic: these bits don't change. */
409 if (ct->status & statusbit) {
410 struct nf_conntrack_tuple target;
412 /* We are aiming to look like inverse of other direction. */
413 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
415 if (!manip_pkt(target.dst.protonum, skb, 0, &target, mtype))
420 EXPORT_SYMBOL_GPL(nf_nat_packet);
422 /* Dir is direction ICMP is coming from (opposite to packet it contains) */
423 int nf_nat_icmp_reply_translation(struct nf_conn *ct,
424 enum ip_conntrack_info ctinfo,
425 unsigned int hooknum,
432 const struct nf_conntrack_l4proto *l4proto;
433 struct nf_conntrack_tuple inner, target;
434 int hdrlen = ip_hdrlen(skb);
435 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
436 unsigned long statusbit;
437 enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
439 if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
442 inside = (void *)skb->data + hdrlen;
444 /* We're actually going to mangle it beyond trivial checksum
445 adjustment, so make sure the current checksum is correct. */
446 if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
449 /* Must be RELATED */
450 NF_CT_ASSERT(skb->nfctinfo == IP_CT_RELATED ||
451 skb->nfctinfo == IP_CT_RELATED+IP_CT_IS_REPLY);
453 /* Redirects on non-null nats must be dropped, else they'll
454 start talking to each other without our translation, and be
456 if (inside->icmp.type == ICMP_REDIRECT) {
457 /* If NAT isn't finished, assume it and drop. */
458 if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
461 if (ct->status & IPS_NAT_MASK)
465 if (manip == IP_NAT_MANIP_SRC)
466 statusbit = IPS_SRC_NAT;
468 statusbit = IPS_DST_NAT;
470 /* Invert if this is reply dir. */
471 if (dir == IP_CT_DIR_REPLY)
472 statusbit ^= IPS_NAT_MASK;
474 if (!(ct->status & statusbit))
477 pr_debug("icmp_reply_translation: translating error %p manip %u "
478 "dir %s\n", skb, manip,
479 dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY");
481 /* rcu_read_lock()ed by nf_hook_slow */
482 l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol);
484 if (!nf_ct_get_tuple(skb, hdrlen + sizeof(struct icmphdr),
486 sizeof(struct icmphdr) + inside->ip.ihl * 4),
487 (u_int16_t)AF_INET, inside->ip.protocol,
488 &inner, l3proto, l4proto))
491 /* Change inner back to look like incoming packet. We do the
492 opposite manip on this hook to normal, because it might not
493 pass all hooks (locally-generated ICMP). Consider incoming
494 packet: PREROUTING (DST manip), routing produces ICMP, goes
495 through POSTROUTING (which must correct the DST manip). */
496 if (!manip_pkt(inside->ip.protocol, skb, hdrlen + sizeof(inside->icmp),
497 &ct->tuplehash[!dir].tuple, !manip))
500 if (skb->ip_summed != CHECKSUM_PARTIAL) {
501 /* Reloading "inside" here since manip_pkt inner. */
502 inside = (void *)skb->data + hdrlen;
503 inside->icmp.checksum = 0;
504 inside->icmp.checksum =
505 csum_fold(skb_checksum(skb, hdrlen,
506 skb->len - hdrlen, 0));
509 /* Change outer to look the reply to an incoming packet
510 * (proto 0 means don't invert per-proto part). */
511 nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
512 if (!manip_pkt(0, skb, 0, &target, manip))
517 EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
519 /* Protocol registration. */
520 int nf_nat_protocol_register(const struct nf_nat_protocol *proto)
524 spin_lock_bh(&nf_nat_lock);
525 if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
529 rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
531 spin_unlock_bh(&nf_nat_lock);
534 EXPORT_SYMBOL(nf_nat_protocol_register);
536 /* Noone stores the protocol anywhere; simply delete it. */
537 void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto)
539 spin_lock_bh(&nf_nat_lock);
540 rcu_assign_pointer(nf_nat_protos[proto->protonum],
541 &nf_nat_unknown_protocol);
542 spin_unlock_bh(&nf_nat_lock);
545 EXPORT_SYMBOL(nf_nat_protocol_unregister);
547 /* Noone using conntrack by the time this called. */
548 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
550 struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
552 if (nat == NULL || nat->ct == NULL)
555 NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK);
557 spin_lock_bh(&nf_nat_lock);
558 hlist_del_rcu(&nat->bysource);
559 spin_unlock_bh(&nf_nat_lock);
562 static void nf_nat_move_storage(void *new, void *old)
564 struct nf_conn_nat *new_nat = new;
565 struct nf_conn_nat *old_nat = old;
566 struct nf_conn *ct = old_nat->ct;
568 if (!ct || !(ct->status & IPS_NAT_DONE_MASK))
571 spin_lock_bh(&nf_nat_lock);
573 hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
574 spin_unlock_bh(&nf_nat_lock);
577 static struct nf_ct_ext_type nat_extend __read_mostly = {
578 .len = sizeof(struct nf_conn_nat),
579 .align = __alignof__(struct nf_conn_nat),
580 .destroy = nf_nat_cleanup_conntrack,
581 .move = nf_nat_move_storage,
583 .flags = NF_CT_EXT_F_PREALLOC,
586 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
588 #include <linux/netfilter/nfnetlink.h>
589 #include <linux/netfilter/nfnetlink_conntrack.h>
591 static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
592 [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
593 [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
596 static int nfnetlink_parse_nat_proto(struct nlattr *attr,
597 const struct nf_conn *ct,
598 struct nf_nat_range *range)
600 struct nlattr *tb[CTA_PROTONAT_MAX+1];
601 const struct nf_nat_protocol *npt;
604 err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
608 npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
609 if (npt->nlattr_to_range)
610 err = npt->nlattr_to_range(tb, range);
611 nf_nat_proto_put(npt);
615 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
616 [CTA_NAT_MINIP] = { .type = NLA_U32 },
617 [CTA_NAT_MAXIP] = { .type = NLA_U32 },
621 nfnetlink_parse_nat(const struct nlattr *nat,
622 const struct nf_conn *ct, struct nf_nat_range *range)
624 struct nlattr *tb[CTA_NAT_MAX+1];
627 memset(range, 0, sizeof(*range));
629 err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
633 if (tb[CTA_NAT_MINIP])
634 range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]);
636 if (!tb[CTA_NAT_MAXIP])
637 range->max_ip = range->min_ip;
639 range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]);
642 range->flags |= IP_NAT_RANGE_MAP_IPS;
644 if (!tb[CTA_NAT_PROTO])
647 err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
655 nfnetlink_parse_nat_setup(struct nf_conn *ct,
656 enum nf_nat_manip_type manip,
657 const struct nlattr *attr)
659 struct nf_nat_range range;
661 if (nfnetlink_parse_nat(attr, ct, &range) < 0)
663 if (nf_nat_initialized(ct, manip))
666 return nf_nat_setup_info(ct, &range, manip);
670 nfnetlink_parse_nat_setup(struct nf_conn *ct,
671 enum nf_nat_manip_type manip,
672 const struct nlattr *attr)
678 static int __net_init nf_nat_net_init(struct net *net)
680 /* Leave them the same for the moment. */
681 net->ipv4.nat_htable_size = net->ct.htable_size;
682 net->ipv4.nat_bysource = nf_ct_alloc_hashtable(&net->ipv4.nat_htable_size,
683 &net->ipv4.nat_vmalloced, 0);
684 if (!net->ipv4.nat_bysource)
689 /* Clear NAT section of all conntracks, in case we're loaded again. */
690 static int clean_nat(struct nf_conn *i, void *data)
692 struct nf_conn_nat *nat = nfct_nat(i);
696 memset(nat, 0, sizeof(*nat));
697 i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK | IPS_SEQ_ADJUST);
701 static void __net_exit nf_nat_net_exit(struct net *net)
703 nf_ct_iterate_cleanup(net, &clean_nat, NULL);
705 nf_ct_free_hashtable(net->ipv4.nat_bysource, net->ipv4.nat_vmalloced,
706 net->ipv4.nat_htable_size);
709 static struct pernet_operations nf_nat_net_ops = {
710 .init = nf_nat_net_init,
711 .exit = nf_nat_net_exit,
714 static int __init nf_nat_init(void)
719 need_ipv4_conntrack();
721 ret = nf_ct_extend_register(&nat_extend);
723 printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
727 ret = register_pernet_subsys(&nf_nat_net_ops);
731 /* Sew in builtin protocols. */
732 spin_lock_bh(&nf_nat_lock);
733 for (i = 0; i < MAX_IP_NAT_PROTO; i++)
734 rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
735 rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
736 rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
737 rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
738 spin_unlock_bh(&nf_nat_lock);
740 /* Initialize fake conntrack so that NAT will skip it */
741 nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
743 l3proto = nf_ct_l3proto_find_get((u_int16_t)AF_INET);
745 BUG_ON(nf_nat_seq_adjust_hook != NULL);
746 rcu_assign_pointer(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
747 BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
748 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook,
749 nfnetlink_parse_nat_setup);
750 BUG_ON(nf_ct_nat_offset != NULL);
751 rcu_assign_pointer(nf_ct_nat_offset, nf_nat_get_offset);
755 nf_ct_extend_unregister(&nat_extend);
759 static void __exit nf_nat_cleanup(void)
761 unregister_pernet_subsys(&nf_nat_net_ops);
762 nf_ct_l3proto_put(l3proto);
763 nf_ct_extend_unregister(&nat_extend);
764 rcu_assign_pointer(nf_nat_seq_adjust_hook, NULL);
765 rcu_assign_pointer(nfnetlink_parse_nat_setup_hook, NULL);
766 rcu_assign_pointer(nf_ct_nat_offset, NULL);
770 MODULE_LICENSE("GPL");
771 MODULE_ALIAS("nf-nat-ipv4");
773 module_init(nf_nat_init);
774 module_exit(nf_nat_cleanup);