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))
31 static const struct xt_table nat_table = {
33 .valid_hooks = NAT_VALID_HOOKS,
40 ipt_snat_target(struct sk_buff *skb, const struct xt_target_param *par)
43 enum ip_conntrack_info ctinfo;
44 const struct nf_nat_multi_range_compat *mr = par->targinfo;
46 NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING);
48 ct = nf_ct_get(skb, &ctinfo);
50 /* Connection must be valid and new. */
51 NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
52 ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY));
53 NF_CT_ASSERT(par->out != NULL);
55 return nf_nat_setup_info(ct, &mr->range[0], IP_NAT_MANIP_SRC);
59 ipt_dnat_target(struct sk_buff *skb, const struct xt_target_param *par)
62 enum ip_conntrack_info ctinfo;
63 const struct nf_nat_multi_range_compat *mr = par->targinfo;
65 NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING ||
66 par->hooknum == NF_INET_LOCAL_OUT);
68 ct = nf_ct_get(skb, &ctinfo);
70 /* Connection must be valid and new. */
71 NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
73 return nf_nat_setup_info(ct, &mr->range[0], IP_NAT_MANIP_DST);
76 static bool ipt_snat_checkentry(const struct xt_tgchk_param *par)
78 const struct nf_nat_multi_range_compat *mr = par->targinfo;
80 /* Must be a valid range */
81 if (mr->rangesize != 1) {
82 printk("SNAT: multiple ranges no longer supported\n");
88 static bool ipt_dnat_checkentry(const struct xt_tgchk_param *par)
90 const struct nf_nat_multi_range_compat *mr = par->targinfo;
92 /* Must be a valid range */
93 if (mr->rangesize != 1) {
94 printk("DNAT: multiple ranges no longer supported\n");
101 alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
103 /* Force range to this IP; let proto decide mapping for
104 per-proto parts (hence not IP_NAT_RANGE_PROTO_SPECIFIED).
105 Use reply in case it's already been mangled (eg local packet).
108 = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
109 ? ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip
110 : ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip);
111 struct nf_nat_range range
112 = { IP_NAT_RANGE_MAP_IPS, ip, ip, { 0 }, { 0 } };
114 pr_debug("Allocating NULL binding for %p (%pI4)\n", ct, &ip);
115 return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
118 int nf_nat_rule_find(struct sk_buff *skb,
119 unsigned int hooknum,
120 const struct net_device *in,
121 const struct net_device *out,
124 struct net *net = nf_ct_net(ct);
127 ret = ipt_do_table(skb, hooknum, in, out, net->ipv4.nat_table);
129 if (ret == NF_ACCEPT) {
130 if (!nf_nat_initialized(ct, HOOK2MANIP(hooknum)))
132 ret = alloc_null_binding(ct, hooknum);
137 static struct xt_target ipt_snat_reg __read_mostly = {
139 .target = ipt_snat_target,
140 .targetsize = sizeof(struct nf_nat_multi_range_compat),
142 .hooks = 1 << NF_INET_POST_ROUTING,
143 .checkentry = ipt_snat_checkentry,
147 static struct xt_target ipt_dnat_reg __read_mostly = {
149 .target = ipt_dnat_target,
150 .targetsize = sizeof(struct nf_nat_multi_range_compat),
152 .hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT),
153 .checkentry = ipt_dnat_checkentry,
157 static int __net_init nf_nat_rule_net_init(struct net *net)
159 struct ipt_replace *repl;
161 repl = ipt_alloc_initial_table(&nat_table);
164 net->ipv4.nat_table = ipt_register_table(net, &nat_table, repl);
166 if (IS_ERR(net->ipv4.nat_table))
167 return PTR_ERR(net->ipv4.nat_table);
171 static void __net_exit nf_nat_rule_net_exit(struct net *net)
173 ipt_unregister_table(net, net->ipv4.nat_table);
176 static struct pernet_operations nf_nat_rule_net_ops = {
177 .init = nf_nat_rule_net_init,
178 .exit = nf_nat_rule_net_exit,
181 int __init nf_nat_rule_init(void)
185 ret = register_pernet_subsys(&nf_nat_rule_net_ops);
188 ret = xt_register_target(&ipt_snat_reg);
190 goto unregister_table;
192 ret = xt_register_target(&ipt_dnat_reg);
194 goto unregister_snat;
199 xt_unregister_target(&ipt_snat_reg);
201 unregister_pernet_subsys(&nf_nat_rule_net_ops);
206 void nf_nat_rule_cleanup(void)
208 xt_unregister_target(&ipt_dnat_reg);
209 xt_unregister_target(&ipt_snat_reg);
210 unregister_pernet_subsys(&nf_nat_rule_net_ops);