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