2 * (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
4 * (C) 2011 Patrick McHardy <kaber@trash.net>
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>
17 #include <linux/jhash.h>
18 #include <linux/rtnetlink.h>
20 #include <net/netfilter/nf_conntrack.h>
21 #include <net/netfilter/nf_conntrack_core.h>
22 #include <net/netfilter/nf_nat.h>
23 #include <net/netfilter/nf_nat_l3proto.h>
24 #include <net/netfilter/nf_nat_l4proto.h>
25 #include <net/netfilter/nf_nat_core.h>
26 #include <net/netfilter/nf_nat_helper.h>
27 #include <net/netfilter/nf_conntrack_helper.h>
28 #include <net/netfilter/nf_conntrack_seqadj.h>
29 #include <net/netfilter/nf_conntrack_l3proto.h>
30 #include <net/netfilter/nf_conntrack_zones.h>
31 #include <linux/netfilter/nf_nat.h>
33 static DEFINE_SPINLOCK(nf_nat_lock
);
35 static DEFINE_MUTEX(nf_nat_proto_mutex
);
36 static const struct nf_nat_l3proto __rcu
*nf_nat_l3protos
[NFPROTO_NUMPROTO
]
38 static const struct nf_nat_l4proto __rcu
**nf_nat_l4protos
[NFPROTO_NUMPROTO
]
42 inline const struct nf_nat_l3proto
*
43 __nf_nat_l3proto_find(u8 family
)
45 return rcu_dereference(nf_nat_l3protos
[family
]);
48 inline const struct nf_nat_l4proto
*
49 __nf_nat_l4proto_find(u8 family
, u8 protonum
)
51 return rcu_dereference(nf_nat_l4protos
[family
][protonum
]);
53 EXPORT_SYMBOL_GPL(__nf_nat_l4proto_find
);
56 static void __nf_nat_decode_session(struct sk_buff
*skb
, struct flowi
*fl
)
58 const struct nf_nat_l3proto
*l3proto
;
59 const struct nf_conn
*ct
;
60 enum ip_conntrack_info ctinfo
;
61 enum ip_conntrack_dir dir
;
62 unsigned long statusbit
;
65 ct
= nf_ct_get(skb
, &ctinfo
);
69 family
= ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
.src
.l3num
;
71 l3proto
= __nf_nat_l3proto_find(family
);
75 dir
= CTINFO2DIR(ctinfo
);
76 if (dir
== IP_CT_DIR_ORIGINAL
)
77 statusbit
= IPS_DST_NAT
;
79 statusbit
= IPS_SRC_NAT
;
81 l3proto
->decode_session(skb
, ct
, dir
, statusbit
, fl
);
86 int nf_xfrm_me_harder(struct net
*net
, struct sk_buff
*skb
, unsigned int family
)
90 struct dst_entry
*dst
;
93 err
= xfrm_decode_session(skb
, &fl
, family
);
99 dst
= ((struct xfrm_dst
*)dst
)->route
;
102 dst
= xfrm_lookup(net
, dst
, &fl
, skb
->sk
, 0);
107 skb_dst_set(skb
, dst
);
109 /* Change in oif may mean change in hh_len. */
110 hh_len
= skb_dst(skb
)->dev
->hard_header_len
;
111 if (skb_headroom(skb
) < hh_len
&&
112 pskb_expand_head(skb
, hh_len
- skb_headroom(skb
), 0, GFP_ATOMIC
))
116 EXPORT_SYMBOL(nf_xfrm_me_harder
);
117 #endif /* CONFIG_XFRM */
119 /* We keep an extra hash for each conntrack, for fast searching. */
120 static inline unsigned int
121 hash_by_src(const struct net
*net
, const struct nf_conntrack_tuple
*tuple
)
125 /* Original src, to ensure we map it consistently if poss. */
126 hash
= jhash2((u32
*)&tuple
->src
, sizeof(tuple
->src
) / sizeof(u32
),
127 tuple
->dst
.protonum
^ nf_conntrack_hash_rnd
);
129 return reciprocal_scale(hash
, net
->ct
.nat_htable_size
);
132 /* Is this tuple already taken? (not by us) */
134 nf_nat_used_tuple(const struct nf_conntrack_tuple
*tuple
,
135 const struct nf_conn
*ignored_conntrack
)
137 /* Conntrack tracking doesn't keep track of outgoing tuples; only
138 * incoming ones. NAT means they don't have a fixed mapping,
139 * so we invert the tuple and look for the incoming reply.
141 * We could keep a separate hash if this proves too slow.
143 struct nf_conntrack_tuple reply
;
145 nf_ct_invert_tuplepr(&reply
, tuple
);
146 return nf_conntrack_tuple_taken(&reply
, ignored_conntrack
);
148 EXPORT_SYMBOL(nf_nat_used_tuple
);
150 /* If we source map this tuple so reply looks like reply_tuple, will
151 * that meet the constraints of range.
153 static int in_range(const struct nf_nat_l3proto
*l3proto
,
154 const struct nf_nat_l4proto
*l4proto
,
155 const struct nf_conntrack_tuple
*tuple
,
156 const struct nf_nat_range
*range
)
158 /* If we are supposed to map IPs, then we must be in the
159 * range specified, otherwise let this drag us onto a new src IP.
161 if (range
->flags
& NF_NAT_RANGE_MAP_IPS
&&
162 !l3proto
->in_range(tuple
, range
))
165 if (!(range
->flags
& NF_NAT_RANGE_PROTO_SPECIFIED
) ||
166 l4proto
->in_range(tuple
, NF_NAT_MANIP_SRC
,
167 &range
->min_proto
, &range
->max_proto
))
174 same_src(const struct nf_conn
*ct
,
175 const struct nf_conntrack_tuple
*tuple
)
177 const struct nf_conntrack_tuple
*t
;
179 t
= &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
;
180 return (t
->dst
.protonum
== tuple
->dst
.protonum
&&
181 nf_inet_addr_cmp(&t
->src
.u3
, &tuple
->src
.u3
) &&
182 t
->src
.u
.all
== tuple
->src
.u
.all
);
185 /* Only called for SRC manip */
187 find_appropriate_src(struct net
*net
,
188 const struct nf_conntrack_zone
*zone
,
189 const struct nf_nat_l3proto
*l3proto
,
190 const struct nf_nat_l4proto
*l4proto
,
191 const struct nf_conntrack_tuple
*tuple
,
192 struct nf_conntrack_tuple
*result
,
193 const struct nf_nat_range
*range
)
195 unsigned int h
= hash_by_src(net
, tuple
);
196 const struct nf_conn_nat
*nat
;
197 const struct nf_conn
*ct
;
199 hlist_for_each_entry_rcu(nat
, &net
->ct
.nat_bysource
[h
], bysource
) {
201 if (same_src(ct
, tuple
) &&
202 nf_ct_zone_equal(ct
, zone
, IP_CT_DIR_ORIGINAL
)) {
203 /* Copy source part from reply tuple. */
204 nf_ct_invert_tuplepr(result
,
205 &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
206 result
->dst
= tuple
->dst
;
208 if (in_range(l3proto
, l4proto
, result
, range
))
215 /* For [FUTURE] fragmentation handling, we want the least-used
216 * src-ip/dst-ip/proto triple. Fairness doesn't come into it. Thus
217 * if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
218 * 1-65535, we don't do pro-rata allocation based on ports; we choose
219 * the ip with the lowest src-ip/dst-ip/proto usage.
222 find_best_ips_proto(const struct nf_conntrack_zone
*zone
,
223 struct nf_conntrack_tuple
*tuple
,
224 const struct nf_nat_range
*range
,
225 const struct nf_conn
*ct
,
226 enum nf_nat_manip_type maniptype
)
228 union nf_inet_addr
*var_ipp
;
231 u32 minip
, maxip
, j
, dist
;
234 /* No IP mapping? Do nothing. */
235 if (!(range
->flags
& NF_NAT_RANGE_MAP_IPS
))
238 if (maniptype
== NF_NAT_MANIP_SRC
)
239 var_ipp
= &tuple
->src
.u3
;
241 var_ipp
= &tuple
->dst
.u3
;
243 /* Fast path: only one choice. */
244 if (nf_inet_addr_cmp(&range
->min_addr
, &range
->max_addr
)) {
245 *var_ipp
= range
->min_addr
;
249 if (nf_ct_l3num(ct
) == NFPROTO_IPV4
)
250 max
= sizeof(var_ipp
->ip
) / sizeof(u32
) - 1;
252 max
= sizeof(var_ipp
->ip6
) / sizeof(u32
) - 1;
254 /* Hashing source and destination IPs gives a fairly even
255 * spread in practice (if there are a small number of IPs
256 * involved, there usually aren't that many connections
257 * anyway). The consistency means that servers see the same
258 * client coming from the same IP (some Internet Banking sites
259 * like this), even across reboots.
261 j
= jhash2((u32
*)&tuple
->src
.u3
, sizeof(tuple
->src
.u3
) / sizeof(u32
),
262 range
->flags
& NF_NAT_RANGE_PERSISTENT
?
263 0 : (__force u32
)tuple
->dst
.u3
.all
[max
] ^ zone
->id
);
266 for (i
= 0; i
<= max
; i
++) {
267 /* If first bytes of the address are at the maximum, use the
268 * distance. Otherwise use the full range.
271 minip
= ntohl((__force __be32
)range
->min_addr
.all
[i
]);
272 maxip
= ntohl((__force __be32
)range
->max_addr
.all
[i
]);
273 dist
= maxip
- minip
+ 1;
279 var_ipp
->all
[i
] = (__force __u32
)
280 htonl(minip
+ reciprocal_scale(j
, dist
));
281 if (var_ipp
->all
[i
] != range
->max_addr
.all
[i
])
284 if (!(range
->flags
& NF_NAT_RANGE_PERSISTENT
))
285 j
^= (__force u32
)tuple
->dst
.u3
.all
[i
];
289 /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
290 * we change the source to map into the range. For NF_INET_PRE_ROUTING
291 * and NF_INET_LOCAL_OUT, we change the destination to map into the
292 * range. It might not be possible to get a unique tuple, but we try.
293 * At worst (or if we race), we will end up with a final duplicate in
294 * __ip_conntrack_confirm and drop the packet. */
296 get_unique_tuple(struct nf_conntrack_tuple
*tuple
,
297 const struct nf_conntrack_tuple
*orig_tuple
,
298 const struct nf_nat_range
*range
,
300 enum nf_nat_manip_type maniptype
)
302 const struct nf_conntrack_zone
*zone
;
303 const struct nf_nat_l3proto
*l3proto
;
304 const struct nf_nat_l4proto
*l4proto
;
305 struct net
*net
= nf_ct_net(ct
);
307 zone
= nf_ct_zone(ct
);
310 l3proto
= __nf_nat_l3proto_find(orig_tuple
->src
.l3num
);
311 l4proto
= __nf_nat_l4proto_find(orig_tuple
->src
.l3num
,
312 orig_tuple
->dst
.protonum
);
314 /* 1) If this srcip/proto/src-proto-part is currently mapped,
315 * and that same mapping gives a unique tuple within the given
318 * This is only required for source (ie. NAT/masq) mappings.
319 * So far, we don't do local source mappings, so multiple
320 * manips not an issue.
322 if (maniptype
== NF_NAT_MANIP_SRC
&&
323 !(range
->flags
& NF_NAT_RANGE_PROTO_RANDOM_ALL
)) {
324 /* try the original tuple first */
325 if (in_range(l3proto
, l4proto
, orig_tuple
, range
)) {
326 if (!nf_nat_used_tuple(orig_tuple
, ct
)) {
327 *tuple
= *orig_tuple
;
330 } else if (find_appropriate_src(net
, zone
, l3proto
, l4proto
,
331 orig_tuple
, tuple
, range
)) {
332 pr_debug("get_unique_tuple: Found current src map\n");
333 if (!nf_nat_used_tuple(tuple
, ct
))
338 /* 2) Select the least-used IP/proto combination in the given range */
339 *tuple
= *orig_tuple
;
340 find_best_ips_proto(zone
, tuple
, range
, ct
, maniptype
);
342 /* 3) The per-protocol part of the manip is made to map into
343 * the range to make a unique tuple.
346 /* Only bother mapping if it's not already in range and unique */
347 if (!(range
->flags
& NF_NAT_RANGE_PROTO_RANDOM_ALL
)) {
348 if (range
->flags
& NF_NAT_RANGE_PROTO_SPECIFIED
) {
349 if (l4proto
->in_range(tuple
, maniptype
,
351 &range
->max_proto
) &&
352 (range
->min_proto
.all
== range
->max_proto
.all
||
353 !nf_nat_used_tuple(tuple
, ct
)))
355 } else if (!nf_nat_used_tuple(tuple
, ct
)) {
360 /* Last change: get protocol to try to obtain unique tuple. */
361 l4proto
->unique_tuple(l3proto
, tuple
, range
, maniptype
, ct
);
366 struct nf_conn_nat
*nf_ct_nat_ext_add(struct nf_conn
*ct
)
368 struct nf_conn_nat
*nat
= nfct_nat(ct
);
372 if (!nf_ct_is_confirmed(ct
))
373 nat
= nf_ct_ext_add(ct
, NF_CT_EXT_NAT
, GFP_ATOMIC
);
377 EXPORT_SYMBOL_GPL(nf_ct_nat_ext_add
);
380 nf_nat_setup_info(struct nf_conn
*ct
,
381 const struct nf_nat_range
*range
,
382 enum nf_nat_manip_type maniptype
)
384 struct net
*net
= nf_ct_net(ct
);
385 struct nf_conntrack_tuple curr_tuple
, new_tuple
;
386 struct nf_conn_nat
*nat
;
388 /* nat helper or nfctnetlink also setup binding */
389 nat
= nf_ct_nat_ext_add(ct
);
393 NF_CT_ASSERT(maniptype
== NF_NAT_MANIP_SRC
||
394 maniptype
== NF_NAT_MANIP_DST
);
395 BUG_ON(nf_nat_initialized(ct
, maniptype
));
397 /* What we've got will look like inverse of reply. Normally
398 * this is what is in the conntrack, except for prior
399 * manipulations (future optimization: if num_manips == 0,
400 * orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
402 nf_ct_invert_tuplepr(&curr_tuple
,
403 &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
405 get_unique_tuple(&new_tuple
, &curr_tuple
, range
, ct
, maniptype
);
407 if (!nf_ct_tuple_equal(&new_tuple
, &curr_tuple
)) {
408 struct nf_conntrack_tuple reply
;
410 /* Alter conntrack table so will recognize replies. */
411 nf_ct_invert_tuplepr(&reply
, &new_tuple
);
412 nf_conntrack_alter_reply(ct
, &reply
);
414 /* Non-atomic: we own this at the moment. */
415 if (maniptype
== NF_NAT_MANIP_SRC
)
416 ct
->status
|= IPS_SRC_NAT
;
418 ct
->status
|= IPS_DST_NAT
;
421 nfct_seqadj_ext_add(ct
);
424 if (maniptype
== NF_NAT_MANIP_SRC
) {
425 unsigned int srchash
;
427 srchash
= hash_by_src(net
,
428 &ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
429 spin_lock_bh(&nf_nat_lock
);
430 /* nf_conntrack_alter_reply might re-allocate extension aera */
433 hlist_add_head_rcu(&nat
->bysource
,
434 &net
->ct
.nat_bysource
[srchash
]);
435 spin_unlock_bh(&nf_nat_lock
);
439 if (maniptype
== NF_NAT_MANIP_DST
)
440 ct
->status
|= IPS_DST_NAT_DONE
;
442 ct
->status
|= IPS_SRC_NAT_DONE
;
446 EXPORT_SYMBOL(nf_nat_setup_info
);
449 __nf_nat_alloc_null_binding(struct nf_conn
*ct
, enum nf_nat_manip_type manip
)
451 /* Force range to this IP; let proto decide mapping for
452 * per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
453 * Use reply in case it's already been mangled (eg local packet).
455 union nf_inet_addr ip
=
456 (manip
== NF_NAT_MANIP_SRC
?
457 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.u3
:
458 ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.u3
);
459 struct nf_nat_range range
= {
460 .flags
= NF_NAT_RANGE_MAP_IPS
,
464 return nf_nat_setup_info(ct
, &range
, manip
);
468 nf_nat_alloc_null_binding(struct nf_conn
*ct
, unsigned int hooknum
)
470 return __nf_nat_alloc_null_binding(ct
, HOOK2MANIP(hooknum
));
472 EXPORT_SYMBOL_GPL(nf_nat_alloc_null_binding
);
474 /* Do packet manipulations according to nf_nat_setup_info. */
475 unsigned int nf_nat_packet(struct nf_conn
*ct
,
476 enum ip_conntrack_info ctinfo
,
477 unsigned int hooknum
,
480 const struct nf_nat_l3proto
*l3proto
;
481 const struct nf_nat_l4proto
*l4proto
;
482 enum ip_conntrack_dir dir
= CTINFO2DIR(ctinfo
);
483 unsigned long statusbit
;
484 enum nf_nat_manip_type mtype
= HOOK2MANIP(hooknum
);
486 if (mtype
== NF_NAT_MANIP_SRC
)
487 statusbit
= IPS_SRC_NAT
;
489 statusbit
= IPS_DST_NAT
;
491 /* Invert if this is reply dir. */
492 if (dir
== IP_CT_DIR_REPLY
)
493 statusbit
^= IPS_NAT_MASK
;
495 /* Non-atomic: these bits don't change. */
496 if (ct
->status
& statusbit
) {
497 struct nf_conntrack_tuple target
;
499 /* We are aiming to look like inverse of other direction. */
500 nf_ct_invert_tuplepr(&target
, &ct
->tuplehash
[!dir
].tuple
);
502 l3proto
= __nf_nat_l3proto_find(target
.src
.l3num
);
503 l4proto
= __nf_nat_l4proto_find(target
.src
.l3num
,
504 target
.dst
.protonum
);
505 if (!l3proto
->manip_pkt(skb
, 0, l4proto
, &target
, mtype
))
510 EXPORT_SYMBOL_GPL(nf_nat_packet
);
512 struct nf_nat_proto_clean
{
517 /* kill conntracks with affected NAT section */
518 static int nf_nat_proto_remove(struct nf_conn
*i
, void *data
)
520 const struct nf_nat_proto_clean
*clean
= data
;
521 struct nf_conn_nat
*nat
= nfct_nat(i
);
526 if ((clean
->l3proto
&& nf_ct_l3num(i
) != clean
->l3proto
) ||
527 (clean
->l4proto
&& nf_ct_protonum(i
) != clean
->l4proto
))
530 return i
->status
& IPS_NAT_MASK
? 1 : 0;
533 static int nf_nat_proto_clean(struct nf_conn
*ct
, void *data
)
535 struct nf_conn_nat
*nat
= nfct_nat(ct
);
537 if (nf_nat_proto_remove(ct
, data
))
540 if (!nat
|| !nat
->ct
)
543 /* This netns is being destroyed, and conntrack has nat null binding.
544 * Remove it from bysource hash, as the table will be freed soon.
546 * Else, when the conntrack is destoyed, nf_nat_cleanup_conntrack()
547 * will delete entry from already-freed table.
549 if (!del_timer(&ct
->timeout
))
552 spin_lock_bh(&nf_nat_lock
);
553 hlist_del_rcu(&nat
->bysource
);
554 ct
->status
&= ~IPS_NAT_DONE_MASK
;
556 spin_unlock_bh(&nf_nat_lock
);
558 add_timer(&ct
->timeout
);
560 /* don't delete conntrack. Although that would make things a lot
561 * simpler, we'd end up flushing all conntracks on nat rmmod.
566 static void nf_nat_l4proto_clean(u8 l3proto
, u8 l4proto
)
568 struct nf_nat_proto_clean clean
= {
576 nf_ct_iterate_cleanup(net
, nf_nat_proto_remove
, &clean
, 0, 0);
580 static void nf_nat_l3proto_clean(u8 l3proto
)
582 struct nf_nat_proto_clean clean
= {
590 nf_ct_iterate_cleanup(net
, nf_nat_proto_remove
, &clean
, 0, 0);
594 /* Protocol registration. */
595 int nf_nat_l4proto_register(u8 l3proto
, const struct nf_nat_l4proto
*l4proto
)
597 const struct nf_nat_l4proto
**l4protos
;
601 mutex_lock(&nf_nat_proto_mutex
);
602 if (nf_nat_l4protos
[l3proto
] == NULL
) {
603 l4protos
= kmalloc(IPPROTO_MAX
* sizeof(struct nf_nat_l4proto
*),
605 if (l4protos
== NULL
) {
610 for (i
= 0; i
< IPPROTO_MAX
; i
++)
611 RCU_INIT_POINTER(l4protos
[i
], &nf_nat_l4proto_unknown
);
613 /* Before making proto_array visible to lockless readers,
614 * we must make sure its content is committed to memory.
618 nf_nat_l4protos
[l3proto
] = l4protos
;
621 if (rcu_dereference_protected(
622 nf_nat_l4protos
[l3proto
][l4proto
->l4proto
],
623 lockdep_is_held(&nf_nat_proto_mutex
)
624 ) != &nf_nat_l4proto_unknown
) {
628 RCU_INIT_POINTER(nf_nat_l4protos
[l3proto
][l4proto
->l4proto
], l4proto
);
630 mutex_unlock(&nf_nat_proto_mutex
);
633 EXPORT_SYMBOL_GPL(nf_nat_l4proto_register
);
635 /* No one stores the protocol anywhere; simply delete it. */
636 void nf_nat_l4proto_unregister(u8 l3proto
, const struct nf_nat_l4proto
*l4proto
)
638 mutex_lock(&nf_nat_proto_mutex
);
639 RCU_INIT_POINTER(nf_nat_l4protos
[l3proto
][l4proto
->l4proto
],
640 &nf_nat_l4proto_unknown
);
641 mutex_unlock(&nf_nat_proto_mutex
);
644 nf_nat_l4proto_clean(l3proto
, l4proto
->l4proto
);
646 EXPORT_SYMBOL_GPL(nf_nat_l4proto_unregister
);
648 int nf_nat_l3proto_register(const struct nf_nat_l3proto
*l3proto
)
652 err
= nf_ct_l3proto_try_module_get(l3proto
->l3proto
);
656 mutex_lock(&nf_nat_proto_mutex
);
657 RCU_INIT_POINTER(nf_nat_l4protos
[l3proto
->l3proto
][IPPROTO_TCP
],
658 &nf_nat_l4proto_tcp
);
659 RCU_INIT_POINTER(nf_nat_l4protos
[l3proto
->l3proto
][IPPROTO_UDP
],
660 &nf_nat_l4proto_udp
);
661 mutex_unlock(&nf_nat_proto_mutex
);
663 RCU_INIT_POINTER(nf_nat_l3protos
[l3proto
->l3proto
], l3proto
);
666 EXPORT_SYMBOL_GPL(nf_nat_l3proto_register
);
668 void nf_nat_l3proto_unregister(const struct nf_nat_l3proto
*l3proto
)
670 mutex_lock(&nf_nat_proto_mutex
);
671 RCU_INIT_POINTER(nf_nat_l3protos
[l3proto
->l3proto
], NULL
);
672 mutex_unlock(&nf_nat_proto_mutex
);
675 nf_nat_l3proto_clean(l3proto
->l3proto
);
676 nf_ct_l3proto_module_put(l3proto
->l3proto
);
678 EXPORT_SYMBOL_GPL(nf_nat_l3proto_unregister
);
680 /* No one using conntrack by the time this called. */
681 static void nf_nat_cleanup_conntrack(struct nf_conn
*ct
)
683 struct nf_conn_nat
*nat
= nf_ct_ext_find(ct
, NF_CT_EXT_NAT
);
685 if (nat
== NULL
|| nat
->ct
== NULL
)
688 NF_CT_ASSERT(nat
->ct
->status
& IPS_SRC_NAT_DONE
);
690 spin_lock_bh(&nf_nat_lock
);
691 hlist_del_rcu(&nat
->bysource
);
692 spin_unlock_bh(&nf_nat_lock
);
695 static void nf_nat_move_storage(void *new, void *old
)
697 struct nf_conn_nat
*new_nat
= new;
698 struct nf_conn_nat
*old_nat
= old
;
699 struct nf_conn
*ct
= old_nat
->ct
;
701 if (!ct
|| !(ct
->status
& IPS_SRC_NAT_DONE
))
704 spin_lock_bh(&nf_nat_lock
);
705 hlist_replace_rcu(&old_nat
->bysource
, &new_nat
->bysource
);
706 spin_unlock_bh(&nf_nat_lock
);
709 static struct nf_ct_ext_type nat_extend __read_mostly
= {
710 .len
= sizeof(struct nf_conn_nat
),
711 .align
= __alignof__(struct nf_conn_nat
),
712 .destroy
= nf_nat_cleanup_conntrack
,
713 .move
= nf_nat_move_storage
,
715 .flags
= NF_CT_EXT_F_PREALLOC
,
718 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
720 #include <linux/netfilter/nfnetlink.h>
721 #include <linux/netfilter/nfnetlink_conntrack.h>
723 static const struct nla_policy protonat_nla_policy
[CTA_PROTONAT_MAX
+1] = {
724 [CTA_PROTONAT_PORT_MIN
] = { .type
= NLA_U16
},
725 [CTA_PROTONAT_PORT_MAX
] = { .type
= NLA_U16
},
728 static int nfnetlink_parse_nat_proto(struct nlattr
*attr
,
729 const struct nf_conn
*ct
,
730 struct nf_nat_range
*range
)
732 struct nlattr
*tb
[CTA_PROTONAT_MAX
+1];
733 const struct nf_nat_l4proto
*l4proto
;
736 err
= nla_parse_nested(tb
, CTA_PROTONAT_MAX
, attr
, protonat_nla_policy
);
740 l4proto
= __nf_nat_l4proto_find(nf_ct_l3num(ct
), nf_ct_protonum(ct
));
741 if (l4proto
->nlattr_to_range
)
742 err
= l4proto
->nlattr_to_range(tb
, range
);
747 static const struct nla_policy nat_nla_policy
[CTA_NAT_MAX
+1] = {
748 [CTA_NAT_V4_MINIP
] = { .type
= NLA_U32
},
749 [CTA_NAT_V4_MAXIP
] = { .type
= NLA_U32
},
750 [CTA_NAT_V6_MINIP
] = { .len
= sizeof(struct in6_addr
) },
751 [CTA_NAT_V6_MAXIP
] = { .len
= sizeof(struct in6_addr
) },
752 [CTA_NAT_PROTO
] = { .type
= NLA_NESTED
},
756 nfnetlink_parse_nat(const struct nlattr
*nat
,
757 const struct nf_conn
*ct
, struct nf_nat_range
*range
,
758 const struct nf_nat_l3proto
*l3proto
)
760 struct nlattr
*tb
[CTA_NAT_MAX
+1];
763 memset(range
, 0, sizeof(*range
));
765 err
= nla_parse_nested(tb
, CTA_NAT_MAX
, nat
, nat_nla_policy
);
769 err
= l3proto
->nlattr_to_range(tb
, range
);
773 if (!tb
[CTA_NAT_PROTO
])
776 return nfnetlink_parse_nat_proto(tb
[CTA_NAT_PROTO
], ct
, range
);
779 /* This function is called under rcu_read_lock() */
781 nfnetlink_parse_nat_setup(struct nf_conn
*ct
,
782 enum nf_nat_manip_type manip
,
783 const struct nlattr
*attr
)
785 struct nf_nat_range range
;
786 const struct nf_nat_l3proto
*l3proto
;
789 /* Should not happen, restricted to creating new conntracks
792 if (WARN_ON_ONCE(nf_nat_initialized(ct
, manip
)))
795 /* Make sure that L3 NAT is there by when we call nf_nat_setup_info to
796 * attach the null binding, otherwise this may oops.
798 l3proto
= __nf_nat_l3proto_find(nf_ct_l3num(ct
));
802 /* No NAT information has been passed, allocate the null-binding */
804 return __nf_nat_alloc_null_binding(ct
, manip
);
806 err
= nfnetlink_parse_nat(attr
, ct
, &range
, l3proto
);
810 return nf_nat_setup_info(ct
, &range
, manip
);
814 nfnetlink_parse_nat_setup(struct nf_conn
*ct
,
815 enum nf_nat_manip_type manip
,
816 const struct nlattr
*attr
)
822 static int __net_init
nf_nat_net_init(struct net
*net
)
824 /* Leave them the same for the moment. */
825 net
->ct
.nat_htable_size
= net
->ct
.htable_size
;
826 net
->ct
.nat_bysource
= nf_ct_alloc_hashtable(&net
->ct
.nat_htable_size
, 0);
827 if (!net
->ct
.nat_bysource
)
832 static void __net_exit
nf_nat_net_exit(struct net
*net
)
834 struct nf_nat_proto_clean clean
= {};
836 nf_ct_iterate_cleanup(net
, nf_nat_proto_clean
, &clean
, 0, 0);
838 nf_ct_free_hashtable(net
->ct
.nat_bysource
, net
->ct
.nat_htable_size
);
841 static struct pernet_operations nf_nat_net_ops
= {
842 .init
= nf_nat_net_init
,
843 .exit
= nf_nat_net_exit
,
846 static struct nf_ct_helper_expectfn follow_master_nat
= {
847 .name
= "nat-follow-master",
848 .expectfn
= nf_nat_follow_master
,
851 static int __init
nf_nat_init(void)
855 ret
= nf_ct_extend_register(&nat_extend
);
857 printk(KERN_ERR
"nf_nat_core: Unable to register extension\n");
861 ret
= register_pernet_subsys(&nf_nat_net_ops
);
865 nf_ct_helper_expectfn_register(&follow_master_nat
);
867 /* Initialize fake conntrack so that NAT will skip it */
868 nf_ct_untracked_status_or(IPS_NAT_DONE_MASK
);
870 BUG_ON(nfnetlink_parse_nat_setup_hook
!= NULL
);
871 RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook
,
872 nfnetlink_parse_nat_setup
);
874 BUG_ON(nf_nat_decode_session_hook
!= NULL
);
875 RCU_INIT_POINTER(nf_nat_decode_session_hook
, __nf_nat_decode_session
);
880 nf_ct_extend_unregister(&nat_extend
);
884 static void __exit
nf_nat_cleanup(void)
888 unregister_pernet_subsys(&nf_nat_net_ops
);
889 nf_ct_extend_unregister(&nat_extend
);
890 nf_ct_helper_expectfn_unregister(&follow_master_nat
);
891 RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook
, NULL
);
893 RCU_INIT_POINTER(nf_nat_decode_session_hook
, NULL
);
895 for (i
= 0; i
< NFPROTO_NUMPROTO
; i
++)
896 kfree(nf_nat_l4protos
[i
]);
900 MODULE_LICENSE("GPL");
902 module_init(nf_nat_init
);
903 module_exit(nf_nat_cleanup
);