linux/net/netfilter/xt_nat.c
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   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
  17static 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
  29static 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
  42static unsigned int
  43xt_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
  59static unsigned int
  60xt_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
  75static unsigned int
  76xt_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
  90static unsigned int
  91xt_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
 104static 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_IN),
 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_OUT),
 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_IN),
 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_OUT),
 147                .me             = THIS_MODULE,
 148        },
 149};
 150
 151static 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
 157static void __exit xt_nat_exit(void)
 158{
 159        xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
 160}
 161
 162module_init(xt_nat_init);
 163module_exit(xt_nat_exit);
 164
 165MODULE_LICENSE("GPL");
 166MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 167MODULE_ALIAS("ipt_SNAT");
 168MODULE_ALIAS("ipt_DNAT");
 169MODULE_ALIAS("ip6t_SNAT");
 170MODULE_ALIAS("ip6t_DNAT");
 171
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