net/netfilter/xt_REDIRECT.c

   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
  31 static unsigned int
  32 redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
  33 {
  34         return nf_nat_redirect_ipv6(skb, par->targinfo, par->hooknum);
  35 }
  36
  37 static 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         return 0;
  44 }
  45
  46 /* FIXME: Take multiple ranges --RR */
  47 static int redirect_tg4_check(const struct xt_tgchk_param *par)
  48 {
  49         const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
  50
  51         if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) {
  52                 pr_debug("bad MAP_IPS.\n");
  53                 return -EINVAL;
  54         }
  55         if (mr->rangesize != 1) {
  56                 pr_debug("bad rangesize %u.\n", mr->rangesize);
  57                 return -EINVAL;
  58         }
  59         return 0;
  60 }
  61
  62 static unsigned int
  63 redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
  64 {
  65         return nf_nat_redirect_ipv4(skb, par->targinfo, par->hooknum);
  66 }
  67
  68 static struct xt_target redirect_tg_reg[] __read_mostly = {
  69         {
  70                 .name       = "REDIRECT",
  71                 .family     = NFPROTO_IPV6,
  72                 .revision   = 0,
  73                 .table      = "nat",
  74                 .checkentry = redirect_tg6_checkentry,
  75                 .target     = redirect_tg6,
  76                 .targetsize = sizeof(struct nf_nat_range),
  77                 .hooks      = (1 << NF_INET_PRE_ROUTING) |
  78                               (1 << NF_INET_LOCAL_OUT),
  79                 .me         = THIS_MODULE,
  80         },
  81         {
  82                 .name       = "REDIRECT",
  83                 .family     = NFPROTO_IPV4,
  84                 .revision   = 0,
  85                 .table      = "nat",
  86                 .target     = redirect_tg4,
  87                 .checkentry = redirect_tg4_check,
  88                 .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
  89                 .hooks      = (1 << NF_INET_PRE_ROUTING) |
  90                               (1 << NF_INET_LOCAL_OUT),
  91                 .me         = THIS_MODULE,
  92         },
  93 };
  94
  95 static int __init redirect_tg_init(void)
  96 {
  97         return xt_register_targets(redirect_tg_reg,
  98                                    ARRAY_SIZE(redirect_tg_reg));
  99 }
 100
 101 static void __exit redirect_tg_exit(void)
 102 {
 103         xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg));
 104 }
 105
 106 module_init(redirect_tg_init);
 107 module_exit(redirect_tg_exit);
 108
 109 MODULE_LICENSE("GPL");
 110 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 111 MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");
 112 MODULE_ALIAS("ip6t_REDIRECT");
 113 MODULE_ALIAS("ipt_REDIRECT");