net/netfilter/xt_nat.c

   1 /*
   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>
   5  *
   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.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/x_tables.h>
  15 #include <net/netfilter/nf_nat_core.h>
  16
  17 static int xt_nat_checkentry_v0(const struct xt_tgchk_param *par)
  18 {
  19         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  20
  21         if (mr->rangesize != 1) {
  22                 pr_info("%s: multiple ranges no longer supported\n",
  23                         par->target->name);
  24                 return -EINVAL;
  25         }
  26         return nf_ct_netns_get(par->net, par->family);
  27 }
  28
  29 static int xt_nat_checkentry(const struct xt_tgchk_param *par)
  30 {
  31         return nf_ct_netns_get(par->net, par->family);
  32 }
  33
  34 static void xt_nat_destroy(const struct xt_tgdtor_param *par)
  35 {
  36         nf_ct_netns_put(par->net, par->family);
  37 }
  38
  39 static void xt_nat_convert_range(struct nf_nat_range *dst,
  40                                  const struct nf_nat_ipv4_range *src)
  41 {
  42         memset(&dst->min_addr, 0, sizeof(dst->min_addr));
  43         memset(&dst->max_addr, 0, sizeof(dst->max_addr));
  44
  45         dst->flags       = src->flags;
  46         dst->min_addr.ip = src->min_ip;
  47         dst->max_addr.ip = src->max_ip;
  48         dst->min_proto   = src->min;
  49         dst->max_proto   = src->max;
  50 }
  51
  52 static unsigned int
  53 xt_snat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  54 {
  55         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  56         struct nf_nat_range range;
  57         enum ip_conntrack_info ctinfo;
  58         struct nf_conn *ct;
  59
  60         ct = nf_ct_get(skb, &ctinfo);
  61         NF_CT_ASSERT(ct != NULL &&
  62                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  63                       ctinfo == IP_CT_RELATED_REPLY));
  64
  65         xt_nat_convert_range(&range, &mr->range[0]);
  66         return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
  67 }
  68
  69 static unsigned int
  70 xt_dnat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  71 {
  72         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  73         struct nf_nat_range range;
  74         enum ip_conntrack_info ctinfo;
  75         struct nf_conn *ct;
  76
  77         ct = nf_ct_get(skb, &ctinfo);
  78         NF_CT_ASSERT(ct != NULL &&
  79                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
  80
  81         xt_nat_convert_range(&range, &mr->range[0]);
  82         return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
  83 }
  84
  85 static unsigned int
  86 xt_snat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
  87 {
  88         const struct nf_nat_range *range = par->targinfo;
  89         enum ip_conntrack_info ctinfo;
  90         struct nf_conn *ct;
  91
  92         ct = nf_ct_get(skb, &ctinfo);
  93         NF_CT_ASSERT(ct != NULL &&
  94                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  95                       ctinfo == IP_CT_RELATED_REPLY));
  96
  97         return nf_nat_setup_info(ct, range, NF_NAT_MANIP_SRC);
  98 }
  99
 100 static unsigned int
 101 xt_dnat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
 102 {
 103         const struct nf_nat_range *range = par->targinfo;
 104         enum ip_conntrack_info ctinfo;
 105         struct nf_conn *ct;
 106
 107         ct = nf_ct_get(skb, &ctinfo);
 108         NF_CT_ASSERT(ct != NULL &&
 109                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
 110
 111         return nf_nat_setup_info(ct, range, NF_NAT_MANIP_DST);
 112 }
 113
 114 static struct xt_target xt_nat_target_reg[] __read_mostly = {
 115         {
 116                 .name           = "SNAT",
 117                 .revision       = 0,
 118                 .checkentry     = xt_nat_checkentry_v0,
 119                 .destroy        = xt_nat_destroy,
 120                 .target         = xt_snat_target_v0,
 121                 .targetsize     = sizeof(struct nf_nat_ipv4_multi_range_compat),
 122                 .family         = NFPROTO_IPV4,
 123                 .table          = "nat",
 124                 .hooks          = (1 << NF_INET_POST_ROUTING) |
 125                                   (1 << NF_INET_LOCAL_IN),
 126                 .me             = THIS_MODULE,
 127         },
 128         {
 129                 .name           = "DNAT",
 130                 .revision       = 0,
 131                 .checkentry     = xt_nat_checkentry_v0,
 132                 .destroy        = xt_nat_destroy,
 133                 .target         = xt_dnat_target_v0,
 134                 .targetsize     = sizeof(struct nf_nat_ipv4_multi_range_compat),
 135                 .family         = NFPROTO_IPV4,
 136                 .table          = "nat",
 137                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
 138                                   (1 << NF_INET_LOCAL_OUT),
 139                 .me             = THIS_MODULE,
 140         },
 141         {
 142                 .name           = "SNAT",
 143                 .revision       = 1,
 144                 .checkentry     = xt_nat_checkentry,
 145                 .destroy        = xt_nat_destroy,
 146                 .target         = xt_snat_target_v1,
 147                 .targetsize     = sizeof(struct nf_nat_range),
 148                 .table          = "nat",
 149                 .hooks          = (1 << NF_INET_POST_ROUTING) |
 150                                   (1 << NF_INET_LOCAL_IN),
 151                 .me             = THIS_MODULE,
 152         },
 153         {
 154                 .name           = "DNAT",
 155                 .revision       = 1,
 156                 .checkentry     = xt_nat_checkentry,
 157                 .destroy        = xt_nat_destroy,
 158                 .target         = xt_dnat_target_v1,
 159                 .targetsize     = sizeof(struct nf_nat_range),
 160                 .table          = "nat",
 161                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
 162                                   (1 << NF_INET_LOCAL_OUT),
 163                 .me             = THIS_MODULE,
 164         },
 165 };
 166
 167 static int __init xt_nat_init(void)
 168 {
 169         return xt_register_targets(xt_nat_target_reg,
 170                                    ARRAY_SIZE(xt_nat_target_reg));
 171 }
 172
 173 static void __exit xt_nat_exit(void)
 174 {
 175         xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
 176 }
 177
 178 module_init(xt_nat_init);
 179 module_exit(xt_nat_exit);
 180
 181 MODULE_LICENSE("GPL");
 182 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 183 MODULE_ALIAS("ipt_SNAT");
 184 MODULE_ALIAS("ipt_DNAT");
 185 MODULE_ALIAS("ip6t_SNAT");
 186 MODULE_ALIAS("ip6t_DNAT");