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 0;
  27 }
  28
  29 static void xt_nat_convert_range(struct nf_nat_range *dst,
  30                                  const struct nf_nat_ipv4_range *src)
  31 {
  32         memset(&dst->min_addr, 0, sizeof(dst->min_addr));
  33         memset(&dst->max_addr, 0, sizeof(dst->max_addr));
  34
  35         dst->flags       = src->flags;
  36         dst->min_addr.ip = src->min_ip;
  37         dst->max_addr.ip = src->max_ip;
  38         dst->min_proto   = src->min;
  39         dst->max_proto   = src->max;
  40 }
  41
  42 static unsigned int
  43 xt_snat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  44 {
  45         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  46         struct nf_nat_range range;
  47         enum ip_conntrack_info ctinfo;
  48         struct nf_conn *ct;
  49
  50         ct = nf_ct_get(skb, &ctinfo);
  51         NF_CT_ASSERT(ct != NULL &&
  52                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  53                       ctinfo == IP_CT_RELATED_REPLY));
  54
  55         xt_nat_convert_range(&range, &mr->range[0]);
  56         return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
  57 }
  58
  59 static unsigned int
  60 xt_dnat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
  61 {
  62         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  63         struct nf_nat_range range;
  64         enum ip_conntrack_info ctinfo;
  65         struct nf_conn *ct;
  66
  67         ct = nf_ct_get(skb, &ctinfo);
  68         NF_CT_ASSERT(ct != NULL &&
  69                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
  70
  71         xt_nat_convert_range(&range, &mr->range[0]);
  72         return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
  73 }
  74
  75 static unsigned int
  76 xt_snat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
  77 {
  78         const struct nf_nat_range *range = par->targinfo;
  79         enum ip_conntrack_info ctinfo;
  80         struct nf_conn *ct;
  81
  82         ct = nf_ct_get(skb, &ctinfo);
  83         NF_CT_ASSERT(ct != NULL &&
  84                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
  85                       ctinfo == IP_CT_RELATED_REPLY));
  86
  87         return nf_nat_setup_info(ct, range, NF_NAT_MANIP_SRC);
  88 }
  89
  90 static unsigned int
  91 xt_dnat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
  92 {
  93         const struct nf_nat_range *range = par->targinfo;
  94         enum ip_conntrack_info ctinfo;
  95         struct nf_conn *ct;
  96
  97         ct = nf_ct_get(skb, &ctinfo);
  98         NF_CT_ASSERT(ct != NULL &&
  99                      (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
 100
 101         return nf_nat_setup_info(ct, range, NF_NAT_MANIP_DST);
 102 }
 103
 104 static struct xt_target xt_nat_target_reg[] __read_mostly = {
 105         {
 106                 .name           = "SNAT",
 107                 .revision       = 0,
 108                 .checkentry     = xt_nat_checkentry_v0,
 109                 .target         = xt_snat_target_v0,
 110                 .targetsize     = sizeof(struct nf_nat_ipv4_multi_range_compat),
 111                 .family         = NFPROTO_IPV4,
 112                 .table          = "nat",
 113                 .hooks          = (1 << NF_INET_POST_ROUTING) |
 114                                   (1 << NF_INET_LOCAL_OUT),
 115                 .me             = THIS_MODULE,
 116         },
 117         {
 118                 .name           = "DNAT",
 119                 .revision       = 0,
 120                 .checkentry     = xt_nat_checkentry_v0,
 121                 .target         = xt_dnat_target_v0,
 122                 .targetsize     = sizeof(struct nf_nat_ipv4_multi_range_compat),
 123                 .family         = NFPROTO_IPV4,
 124                 .table          = "nat",
 125                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
 126                                   (1 << NF_INET_LOCAL_IN),
 127                 .me             = THIS_MODULE,
 128         },
 129         {
 130                 .name           = "SNAT",
 131                 .revision       = 1,
 132                 .target         = xt_snat_target_v1,
 133                 .targetsize     = sizeof(struct nf_nat_range),
 134                 .table          = "nat",
 135                 .hooks          = (1 << NF_INET_POST_ROUTING) |
 136                                   (1 << NF_INET_LOCAL_OUT),
 137                 .me             = THIS_MODULE,
 138         },
 139         {
 140                 .name           = "DNAT",
 141                 .revision       = 1,
 142                 .target         = xt_dnat_target_v1,
 143                 .targetsize     = sizeof(struct nf_nat_range),
 144                 .table          = "nat",
 145                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
 146                                   (1 << NF_INET_LOCAL_IN),
 147                 .me             = THIS_MODULE,
 148         },
 149 };
 150
 151 static int __init xt_nat_init(void)
 152 {
 153         return xt_register_targets(xt_nat_target_reg,
 154                                    ARRAY_SIZE(xt_nat_target_reg));
 155 }
 156
 157 static void __exit xt_nat_exit(void)
 158 {
 159         xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
 160 }
 161
 162 module_init(xt_nat_init);
 163 module_exit(xt_nat_exit);
 164
 165 MODULE_LICENSE("GPL");
 166 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 167 MODULE_ALIAS("ipt_SNAT");
 168 MODULE_ALIAS("ipt_DNAT");
 169 MODULE_ALIAS("ip6t_SNAT");
 170 MODULE_ALIAS("ip6t_DNAT");