LXR linux/net/netfilter/xt

   1/*
   2 * (C) 1999-2001 Paul `Rusty' Russell
   3 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   4 * Copyright (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 * Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
  11 * NAT funded by Astaro.
  12 */
  13
  14#include <linux/if.h>
  15#include <linux/inetdevice.h>
  16#include <linux/ip.h>
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/netdevice.h>
  20#include <linux/netfilter.h>
  21#include <linux/types.h>
  22#include <linux/netfilter_ipv4.h>
  23#include <linux/netfilter_ipv6.h>
  24#include <linux/netfilter/x_tables.h>
  25#include <net/addrconf.h>
  26#include <net/checksum.h>
  27#include <net/protocol.h>
  28#include <net/netfilter/nf_nat.h>
  29#include <net/netfilter/nf_nat_redirect.h>
  30
  31static unsigned int
  32redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
  33{
  34        return nf_nat_redirect_ipv6(skb, par->targinfo, xt_hooknum(par));
  35}
  36
  37static int redirect_tg6_checkentry(const struct xt_tgchk_param *par)
  38{
  39        const struct nf_nat_range *range = par->targinfo;
  40
  41        if (range->flags & NF_NAT_RANGE_MAP_IPS)
  42                return -EINVAL;
  43
  44        return nf_ct_netns_get(par->net, par->family);
  45}
  46
  47static void redirect_tg_destroy(const struct xt_tgdtor_param *par)
  48{
  49        nf_ct_netns_put(par->net, par->family);
  50}
  51
  52/* FIXME: Take multiple ranges --RR */
  53static int redirect_tg4_check(const struct xt_tgchk_param *par)
  54{
  55        const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  56
  57        if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) {
  58                pr_debug("bad MAP_IPS.\n");
  59                return -EINVAL;
  60        }
  61        if (mr->rangesize != 1) {
  62                pr_debug("bad rangesize %u.\n", mr->rangesize);
  63                return -EINVAL;
  64        }
  65        return nf_ct_netns_get(par->net, par->family);
  66}
  67
  68static unsigned int
  69redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
  70{
  71        return nf_nat_redirect_ipv4(skb, par->targinfo, xt_hooknum(par));
  72}
  73
  74static struct xt_target redirect_tg_reg[] __read_mostly = {
  75        {
  76                .name       = "REDIRECT",
  77                .family     = NFPROTO_IPV6,
  78                .revision   = 0,
  79                .table      = "nat",
  80                .checkentry = redirect_tg6_checkentry,
  81                .destroy    = redirect_tg_destroy,
  82                .target     = redirect_tg6,
  83                .targetsize = sizeof(struct nf_nat_range),
  84                .hooks      = (1 << NF_INET_PRE_ROUTING) |
  85                              (1 << NF_INET_LOCAL_OUT),
  86                .me         = THIS_MODULE,
  87        },
  88        {
  89                .name       = "REDIRECT",
  90                .family     = NFPROTO_IPV4,
  91                .revision   = 0,
  92                .table      = "nat",
  93                .target     = redirect_tg4,
  94                .checkentry = redirect_tg4_check,
  95                .destroy    = redirect_tg_destroy,
  96                .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
  97                .hooks      = (1 << NF_INET_PRE_ROUTING) |
  98                              (1 << NF_INET_LOCAL_OUT),
  99                .me         = THIS_MODULE,
 100        },
 101};
 102
 103static int __init redirect_tg_init(void)
 104{
 105        return xt_register_targets(redirect_tg_reg,
 106                                   ARRAY_SIZE(redirect_tg_reg));
 107}
 108
 109static void __exit redirect_tg_exit(void)
 110{
 111        xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg));
 112}
 113
 114module_init(redirect_tg_init);
 115module_exit(redirect_tg_exit);
 116
 117MODULE_LICENSE("GPL");
 118MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 119MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");
 120MODULE_ALIAS("ip6t_REDIRECT");
 121MODULE_ALIAS("ipt_REDIRECT");
 122