2 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * Development of IPv6 NAT funded by Astaro.
10 #include <linux/types.h>
11 #include <linux/module.h>
12 #include <linux/skbuff.h>
13 #include <linux/ipv6.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv6.h>
16 #include <net/secure_seq.h>
17 #include <net/checksum.h>
18 #include <net/ip6_checksum.h>
19 #include <net/ip6_route.h>
22 #include <net/netfilter/nf_conntrack_core.h>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_nat_core.h>
25 #include <net/netfilter/nf_nat_l3proto.h>
26 #include <net/netfilter/nf_nat_l4proto.h>
28 static const struct nf_nat_l3proto nf_nat_l3proto_ipv6
;
31 static void nf_nat_ipv6_decode_session(struct sk_buff
*skb
,
32 const struct nf_conn
*ct
,
33 enum ip_conntrack_dir dir
,
34 unsigned long statusbit
,
37 const struct nf_conntrack_tuple
*t
= &ct
->tuplehash
[dir
].tuple
;
38 struct flowi6
*fl6
= &fl
->u
.ip6
;
40 if (ct
->status
& statusbit
) {
41 fl6
->daddr
= t
->dst
.u3
.in6
;
42 if (t
->dst
.protonum
== IPPROTO_TCP
||
43 t
->dst
.protonum
== IPPROTO_UDP
||
44 t
->dst
.protonum
== IPPROTO_UDPLITE
||
45 t
->dst
.protonum
== IPPROTO_DCCP
||
46 t
->dst
.protonum
== IPPROTO_SCTP
)
47 fl6
->fl6_dport
= t
->dst
.u
.all
;
50 statusbit
^= IPS_NAT_MASK
;
52 if (ct
->status
& statusbit
) {
53 fl6
->saddr
= t
->src
.u3
.in6
;
54 if (t
->dst
.protonum
== IPPROTO_TCP
||
55 t
->dst
.protonum
== IPPROTO_UDP
||
56 t
->dst
.protonum
== IPPROTO_UDPLITE
||
57 t
->dst
.protonum
== IPPROTO_DCCP
||
58 t
->dst
.protonum
== IPPROTO_SCTP
)
59 fl6
->fl6_sport
= t
->src
.u
.all
;
64 static bool nf_nat_ipv6_in_range(const struct nf_conntrack_tuple
*t
,
65 const struct nf_nat_range
*range
)
67 return ipv6_addr_cmp(&t
->src
.u3
.in6
, &range
->min_addr
.in6
) >= 0 &&
68 ipv6_addr_cmp(&t
->src
.u3
.in6
, &range
->max_addr
.in6
) <= 0;
71 static u32
nf_nat_ipv6_secure_port(const struct nf_conntrack_tuple
*t
,
74 return secure_ipv6_port_ephemeral(t
->src
.u3
.ip6
, t
->dst
.u3
.ip6
, dport
);
77 static bool nf_nat_ipv6_manip_pkt(struct sk_buff
*skb
,
78 unsigned int iphdroff
,
79 const struct nf_nat_l4proto
*l4proto
,
80 const struct nf_conntrack_tuple
*target
,
81 enum nf_nat_manip_type maniptype
)
83 struct ipv6hdr
*ipv6h
;
88 if (!skb_make_writable(skb
, iphdroff
+ sizeof(*ipv6h
)))
91 ipv6h
= (void *)skb
->data
+ iphdroff
;
92 nexthdr
= ipv6h
->nexthdr
;
93 hdroff
= ipv6_skip_exthdr(skb
, iphdroff
+ sizeof(*ipv6h
),
98 if ((frag_off
& htons(~0x7)) == 0 &&
99 !l4proto
->manip_pkt(skb
, &nf_nat_l3proto_ipv6
, iphdroff
, hdroff
,
103 if (maniptype
== NF_NAT_MANIP_SRC
)
104 ipv6h
->saddr
= target
->src
.u3
.in6
;
106 ipv6h
->daddr
= target
->dst
.u3
.in6
;
111 static void nf_nat_ipv6_csum_update(struct sk_buff
*skb
,
112 unsigned int iphdroff
, __sum16
*check
,
113 const struct nf_conntrack_tuple
*t
,
114 enum nf_nat_manip_type maniptype
)
116 const struct ipv6hdr
*ipv6h
= (struct ipv6hdr
*)(skb
->data
+ iphdroff
);
117 const struct in6_addr
*oldip
, *newip
;
119 if (maniptype
== NF_NAT_MANIP_SRC
) {
120 oldip
= &ipv6h
->saddr
;
121 newip
= &t
->src
.u3
.in6
;
123 oldip
= &ipv6h
->daddr
;
124 newip
= &t
->dst
.u3
.in6
;
126 inet_proto_csum_replace16(check
, skb
, oldip
->s6_addr32
,
127 newip
->s6_addr32
, true);
130 static void nf_nat_ipv6_csum_recalc(struct sk_buff
*skb
,
131 u8 proto
, void *data
, __sum16
*check
,
132 int datalen
, int oldlen
)
134 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
) {
135 const struct ipv6hdr
*ipv6h
= ipv6_hdr(skb
);
137 skb
->ip_summed
= CHECKSUM_PARTIAL
;
138 skb
->csum_start
= skb_headroom(skb
) + skb_network_offset(skb
) +
139 (data
- (void *)skb
->data
);
140 skb
->csum_offset
= (void *)check
- data
;
141 *check
= ~csum_ipv6_magic(&ipv6h
->saddr
, &ipv6h
->daddr
,
144 inet_proto_csum_replace2(check
, skb
,
145 htons(oldlen
), htons(datalen
), true);
148 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
149 static int nf_nat_ipv6_nlattr_to_range(struct nlattr
*tb
[],
150 struct nf_nat_range
*range
)
152 if (tb
[CTA_NAT_V6_MINIP
]) {
153 nla_memcpy(&range
->min_addr
.ip6
, tb
[CTA_NAT_V6_MINIP
],
154 sizeof(struct in6_addr
));
155 range
->flags
|= NF_NAT_RANGE_MAP_IPS
;
158 if (tb
[CTA_NAT_V6_MAXIP
])
159 nla_memcpy(&range
->max_addr
.ip6
, tb
[CTA_NAT_V6_MAXIP
],
160 sizeof(struct in6_addr
));
162 range
->max_addr
= range
->min_addr
;
168 static const struct nf_nat_l3proto nf_nat_l3proto_ipv6
= {
169 .l3proto
= NFPROTO_IPV6
,
170 .secure_port
= nf_nat_ipv6_secure_port
,
171 .in_range
= nf_nat_ipv6_in_range
,
172 .manip_pkt
= nf_nat_ipv6_manip_pkt
,
173 .csum_update
= nf_nat_ipv6_csum_update
,
174 .csum_recalc
= nf_nat_ipv6_csum_recalc
,
175 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
176 .nlattr_to_range
= nf_nat_ipv6_nlattr_to_range
,
179 .decode_session
= nf_nat_ipv6_decode_session
,
183 int nf_nat_icmpv6_reply_translation(struct sk_buff
*skb
,
185 enum ip_conntrack_info ctinfo
,
186 unsigned int hooknum
,
190 struct icmp6hdr icmp6
;
193 enum ip_conntrack_dir dir
= CTINFO2DIR(ctinfo
);
194 enum nf_nat_manip_type manip
= HOOK2MANIP(hooknum
);
195 const struct nf_nat_l4proto
*l4proto
;
196 struct nf_conntrack_tuple target
;
197 unsigned long statusbit
;
199 NF_CT_ASSERT(ctinfo
== IP_CT_RELATED
|| ctinfo
== IP_CT_RELATED_REPLY
);
201 if (!skb_make_writable(skb
, hdrlen
+ sizeof(*inside
)))
203 if (nf_ip6_checksum(skb
, hooknum
, hdrlen
, IPPROTO_ICMPV6
))
206 inside
= (void *)skb
->data
+ hdrlen
;
207 if (inside
->icmp6
.icmp6_type
== NDISC_REDIRECT
) {
208 if ((ct
->status
& IPS_NAT_DONE_MASK
) != IPS_NAT_DONE_MASK
)
210 if (ct
->status
& IPS_NAT_MASK
)
214 if (manip
== NF_NAT_MANIP_SRC
)
215 statusbit
= IPS_SRC_NAT
;
217 statusbit
= IPS_DST_NAT
;
219 /* Invert if this is reply direction */
220 if (dir
== IP_CT_DIR_REPLY
)
221 statusbit
^= IPS_NAT_MASK
;
223 if (!(ct
->status
& statusbit
))
226 l4proto
= __nf_nat_l4proto_find(NFPROTO_IPV6
, inside
->ip6
.nexthdr
);
227 if (!nf_nat_ipv6_manip_pkt(skb
, hdrlen
+ sizeof(inside
->icmp6
),
228 l4proto
, &ct
->tuplehash
[!dir
].tuple
, !manip
))
231 if (skb
->ip_summed
!= CHECKSUM_PARTIAL
) {
232 struct ipv6hdr
*ipv6h
= ipv6_hdr(skb
);
233 inside
= (void *)skb
->data
+ hdrlen
;
234 inside
->icmp6
.icmp6_cksum
= 0;
235 inside
->icmp6
.icmp6_cksum
=
236 csum_ipv6_magic(&ipv6h
->saddr
, &ipv6h
->daddr
,
237 skb
->len
- hdrlen
, IPPROTO_ICMPV6
,
238 csum_partial(&inside
->icmp6
,
239 skb
->len
- hdrlen
, 0));
242 nf_ct_invert_tuplepr(&target
, &ct
->tuplehash
[!dir
].tuple
);
243 l4proto
= __nf_nat_l4proto_find(NFPROTO_IPV6
, IPPROTO_ICMPV6
);
244 if (!nf_nat_ipv6_manip_pkt(skb
, 0, l4proto
, &target
, manip
))
249 EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation
);
252 nf_nat_ipv6_fn(void *priv
, struct sk_buff
*skb
,
253 const struct nf_hook_state
*state
,
254 unsigned int (*do_chain
)(void *priv
,
256 const struct nf_hook_state
*state
,
260 enum ip_conntrack_info ctinfo
;
261 struct nf_conn_nat
*nat
;
262 enum nf_nat_manip_type maniptype
= HOOK2MANIP(state
->hook
);
267 ct
= nf_ct_get(skb
, &ctinfo
);
268 /* Can't track? It's not due to stress, or conntrack would
269 * have dropped it. Hence it's the user's responsibilty to
270 * packet filter it out, or implement conntrack/NAT for that
276 /* Don't try to NAT if this packet is not conntracked */
277 if (nf_ct_is_untracked(ct
))
280 nat
= nf_ct_nat_ext_add(ct
);
286 case IP_CT_RELATED_REPLY
:
287 nexthdr
= ipv6_hdr(skb
)->nexthdr
;
288 hdrlen
= ipv6_skip_exthdr(skb
, sizeof(struct ipv6hdr
),
289 &nexthdr
, &frag_off
);
291 if (hdrlen
>= 0 && nexthdr
== IPPROTO_ICMPV6
) {
292 if (!nf_nat_icmpv6_reply_translation(skb
, ct
, ctinfo
,
299 /* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
301 /* Seen it before? This can happen for loopback, retrans,
304 if (!nf_nat_initialized(ct
, maniptype
)) {
307 ret
= do_chain(priv
, skb
, state
, ct
);
308 if (ret
!= NF_ACCEPT
)
311 if (nf_nat_initialized(ct
, HOOK2MANIP(state
->hook
)))
314 ret
= nf_nat_alloc_null_binding(ct
, state
->hook
);
315 if (ret
!= NF_ACCEPT
)
318 pr_debug("Already setup manip %s for ct %p\n",
319 maniptype
== NF_NAT_MANIP_SRC
? "SRC" : "DST",
321 if (nf_nat_oif_changed(state
->hook
, ctinfo
, nat
, state
->out
))
328 NF_CT_ASSERT(ctinfo
== IP_CT_ESTABLISHED
||
329 ctinfo
== IP_CT_ESTABLISHED_REPLY
);
330 if (nf_nat_oif_changed(state
->hook
, ctinfo
, nat
, state
->out
))
334 return nf_nat_packet(ct
, ctinfo
, state
->hook
, skb
);
337 nf_ct_kill_acct(ct
, ctinfo
, skb
);
340 EXPORT_SYMBOL_GPL(nf_nat_ipv6_fn
);
343 nf_nat_ipv6_in(void *priv
, struct sk_buff
*skb
,
344 const struct nf_hook_state
*state
,
345 unsigned int (*do_chain
)(void *priv
,
347 const struct nf_hook_state
*state
,
351 struct in6_addr daddr
= ipv6_hdr(skb
)->daddr
;
353 ret
= nf_nat_ipv6_fn(priv
, skb
, state
, do_chain
);
354 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
&&
355 ipv6_addr_cmp(&daddr
, &ipv6_hdr(skb
)->daddr
))
360 EXPORT_SYMBOL_GPL(nf_nat_ipv6_in
);
363 nf_nat_ipv6_out(void *priv
, struct sk_buff
*skb
,
364 const struct nf_hook_state
*state
,
365 unsigned int (*do_chain
)(void *priv
,
367 const struct nf_hook_state
*state
,
371 const struct nf_conn
*ct
;
372 enum ip_conntrack_info ctinfo
;
377 /* root is playing with raw sockets. */
378 if (skb
->len
< sizeof(struct ipv6hdr
))
381 ret
= nf_nat_ipv6_fn(priv
, skb
, state
, do_chain
);
383 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
&&
384 !(IP6CB(skb
)->flags
& IP6SKB_XFRM_TRANSFORMED
) &&
385 (ct
= nf_ct_get(skb
, &ctinfo
)) != NULL
) {
386 enum ip_conntrack_dir dir
= CTINFO2DIR(ctinfo
);
388 if (!nf_inet_addr_cmp(&ct
->tuplehash
[dir
].tuple
.src
.u3
,
389 &ct
->tuplehash
[!dir
].tuple
.dst
.u3
) ||
390 (ct
->tuplehash
[dir
].tuple
.dst
.protonum
!= IPPROTO_ICMPV6
&&
391 ct
->tuplehash
[dir
].tuple
.src
.u
.all
!=
392 ct
->tuplehash
[!dir
].tuple
.dst
.u
.all
)) {
393 err
= nf_xfrm_me_harder(state
->net
, skb
, AF_INET6
);
395 ret
= NF_DROP_ERR(err
);
401 EXPORT_SYMBOL_GPL(nf_nat_ipv6_out
);
404 nf_nat_ipv6_local_fn(void *priv
, struct sk_buff
*skb
,
405 const struct nf_hook_state
*state
,
406 unsigned int (*do_chain
)(void *priv
,
408 const struct nf_hook_state
*state
,
411 const struct nf_conn
*ct
;
412 enum ip_conntrack_info ctinfo
;
416 /* root is playing with raw sockets. */
417 if (skb
->len
< sizeof(struct ipv6hdr
))
420 ret
= nf_nat_ipv6_fn(priv
, skb
, state
, do_chain
);
421 if (ret
!= NF_DROP
&& ret
!= NF_STOLEN
&&
422 (ct
= nf_ct_get(skb
, &ctinfo
)) != NULL
) {
423 enum ip_conntrack_dir dir
= CTINFO2DIR(ctinfo
);
425 if (!nf_inet_addr_cmp(&ct
->tuplehash
[dir
].tuple
.dst
.u3
,
426 &ct
->tuplehash
[!dir
].tuple
.src
.u3
)) {
427 err
= ip6_route_me_harder(state
->net
, skb
);
429 ret
= NF_DROP_ERR(err
);
432 else if (!(IP6CB(skb
)->flags
& IP6SKB_XFRM_TRANSFORMED
) &&
433 ct
->tuplehash
[dir
].tuple
.dst
.protonum
!= IPPROTO_ICMPV6
&&
434 ct
->tuplehash
[dir
].tuple
.dst
.u
.all
!=
435 ct
->tuplehash
[!dir
].tuple
.src
.u
.all
) {
436 err
= nf_xfrm_me_harder(state
->net
, skb
, AF_INET6
);
438 ret
= NF_DROP_ERR(err
);
444 EXPORT_SYMBOL_GPL(nf_nat_ipv6_local_fn
);
446 static int __init
nf_nat_l3proto_ipv6_init(void)
450 err
= nf_nat_l4proto_register(NFPROTO_IPV6
, &nf_nat_l4proto_icmpv6
);
453 err
= nf_nat_l3proto_register(&nf_nat_l3proto_ipv6
);
459 nf_nat_l4proto_unregister(NFPROTO_IPV6
, &nf_nat_l4proto_icmpv6
);
464 static void __exit
nf_nat_l3proto_ipv6_exit(void)
466 nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6
);
467 nf_nat_l4proto_unregister(NFPROTO_IPV6
, &nf_nat_l4proto_icmpv6
);
470 MODULE_LICENSE("GPL");
471 MODULE_ALIAS("nf-nat-" __stringify(AF_INET6
));
473 module_init(nf_nat_l3proto_ipv6_init
);
474 module_exit(nf_nat_l3proto_ipv6_exit
);