1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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.
9 /* Everything about the rules for NAT. */
10 #include <linux/types.h>
12 #include <linux/netfilter.h>
13 #include <linux/netfilter_ipv4.h>
14 #include <linux/module.h>
15 #include <linux/kmod.h>
16 #include <linux/skbuff.h>
17 #include <linux/proc_fs.h>
18 #include <net/checksum.h>
19 #include <net/route.h>
20 #include <linux/bitops.h>
22 #include <linux/netfilter_ipv4/ip_tables.h>
23 #include <net/netfilter/nf_nat.h>
24 #include <net/netfilter/nf_nat_core.h>
25 #include <net/netfilter/nf_nat_rule.h>
27 #define NAT_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
28 (1 << NF_INET_POST_ROUTING) | \
29 (1 << NF_INET_LOCAL_OUT))
33 struct ipt_replace repl
;
34 struct ipt_standard entries
[3];
35 struct ipt_error term
;
36 } nat_initial_table __net_initdata
= {
39 .valid_hooks
= NAT_VALID_HOOKS
,
41 .size
= sizeof(struct ipt_standard
) * 3 + sizeof(struct ipt_error
),
43 [NF_INET_PRE_ROUTING
] = 0,
44 [NF_INET_POST_ROUTING
] = sizeof(struct ipt_standard
),
45 [NF_INET_LOCAL_OUT
] = sizeof(struct ipt_standard
) * 2
48 [NF_INET_PRE_ROUTING
] = 0,
49 [NF_INET_POST_ROUTING
] = sizeof(struct ipt_standard
),
50 [NF_INET_LOCAL_OUT
] = sizeof(struct ipt_standard
) * 2
54 IPT_STANDARD_INIT(NF_ACCEPT
), /* PRE_ROUTING */
55 IPT_STANDARD_INIT(NF_ACCEPT
), /* POST_ROUTING */
56 IPT_STANDARD_INIT(NF_ACCEPT
), /* LOCAL_OUT */
58 .term
= IPT_ERROR_INIT
, /* ERROR */
61 static struct xt_table nat_table
= {
63 .valid_hooks
= NAT_VALID_HOOKS
,
70 ipt_snat_target(struct sk_buff
*skb
, const struct xt_target_param
*par
)
73 enum ip_conntrack_info ctinfo
;
74 const struct nf_nat_multi_range_compat
*mr
= par
->targinfo
;
76 NF_CT_ASSERT(par
->hooknum
== NF_INET_POST_ROUTING
);
78 ct
= nf_ct_get(skb
, &ctinfo
);
80 /* Connection must be valid and new. */
81 NF_CT_ASSERT(ct
&& (ctinfo
== IP_CT_NEW
|| ctinfo
== IP_CT_RELATED
||
82 ctinfo
== IP_CT_RELATED
+ IP_CT_IS_REPLY
));
83 NF_CT_ASSERT(par
->out
!= NULL
);
85 return nf_nat_setup_info(ct
, &mr
->range
[0], IP_NAT_MANIP_SRC
);
89 ipt_dnat_target(struct sk_buff
*skb
, const struct xt_target_param
*par
)
92 enum ip_conntrack_info ctinfo
;
93 const struct nf_nat_multi_range_compat
*mr
= par
->targinfo
;
95 NF_CT_ASSERT(par
->hooknum
== NF_INET_PRE_ROUTING
||
96 par
->hooknum
== NF_INET_LOCAL_OUT
);
98 ct
= nf_ct_get(skb
, &ctinfo
);
100 /* Connection must be valid and new. */
101 NF_CT_ASSERT(ct
&& (ctinfo
== IP_CT_NEW
|| ctinfo
== IP_CT_RELATED
));
103 return nf_nat_setup_info(ct
, &mr
->range
[0], IP_NAT_MANIP_DST
);
106 static bool ipt_snat_checkentry(const struct xt_tgchk_param
*par
)
108 const struct nf_nat_multi_range_compat
*mr
= par
->targinfo
;
110 /* Must be a valid range */
111 if (mr
->rangesize
!= 1) {
112 printk("SNAT: multiple ranges no longer supported\n");
118 static bool ipt_dnat_checkentry(const struct xt_tgchk_param
*par
)
120 const struct nf_nat_multi_range_compat
*mr
= par
->targinfo
;
122 /* Must be a valid range */
123 if (mr
->rangesize
!= 1) {
124 printk("DNAT: multiple ranges no longer supported\n");
131 alloc_null_binding(struct nf_conn
*ct
, unsigned int hooknum
)
133 /* Force range to this IP; let proto decide mapping for
134 per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
135 Use reply in case it's already been mangled (eg local packet).
138 = (HOOK2MANIP(hooknum
) == IP_NAT_MANIP_SRC
139 ? ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.u3
.ip
140 : ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.src
.u3
.ip
);
141 struct nf_nat_range range
142 = { IP_NAT_RANGE_MAP_IPS
, ip
, ip
, { 0 }, { 0 } };
144 pr_debug("Allocating NULL binding for %p (%pI4)\n", ct
, &ip
);
145 return nf_nat_setup_info(ct
, &range
, HOOK2MANIP(hooknum
));
148 int nf_nat_rule_find(struct sk_buff
*skb
,
149 unsigned int hooknum
,
150 const struct net_device
*in
,
151 const struct net_device
*out
,
154 struct net
*net
= nf_ct_net(ct
);
157 ret
= ipt_do_table(skb
, hooknum
, in
, out
, net
->ipv4
.nat_table
);
159 if (ret
== NF_ACCEPT
) {
160 if (!nf_nat_initialized(ct
, HOOK2MANIP(hooknum
)))
162 ret
= alloc_null_binding(ct
, hooknum
);
167 static struct xt_target ipt_snat_reg __read_mostly
= {
169 .target
= ipt_snat_target
,
170 .targetsize
= sizeof(struct nf_nat_multi_range_compat
),
172 .hooks
= 1 << NF_INET_POST_ROUTING
,
173 .checkentry
= ipt_snat_checkentry
,
177 static struct xt_target ipt_dnat_reg __read_mostly
= {
179 .target
= ipt_dnat_target
,
180 .targetsize
= sizeof(struct nf_nat_multi_range_compat
),
182 .hooks
= (1 << NF_INET_PRE_ROUTING
) | (1 << NF_INET_LOCAL_OUT
),
183 .checkentry
= ipt_dnat_checkentry
,
187 static int __net_init
nf_nat_rule_net_init(struct net
*net
)
189 net
->ipv4
.nat_table
= ipt_register_table(net
, &nat_table
,
190 &nat_initial_table
.repl
);
191 if (IS_ERR(net
->ipv4
.nat_table
))
192 return PTR_ERR(net
->ipv4
.nat_table
);
196 static void __net_exit
nf_nat_rule_net_exit(struct net
*net
)
198 ipt_unregister_table(net
->ipv4
.nat_table
);
201 static struct pernet_operations nf_nat_rule_net_ops
= {
202 .init
= nf_nat_rule_net_init
,
203 .exit
= nf_nat_rule_net_exit
,
206 int __init
nf_nat_rule_init(void)
210 ret
= register_pernet_subsys(&nf_nat_rule_net_ops
);
213 ret
= xt_register_target(&ipt_snat_reg
);
215 goto unregister_table
;
217 ret
= xt_register_target(&ipt_dnat_reg
);
219 goto unregister_snat
;
224 xt_unregister_target(&ipt_snat_reg
);
226 unregister_pernet_subsys(&nf_nat_rule_net_ops
);
231 void nf_nat_rule_cleanup(void)
233 xt_unregister_target(&ipt_dnat_reg
);
234 xt_unregister_target(&ipt_snat_reg
);
235 unregister_pernet_subsys(&nf_nat_rule_net_ops
);