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   1 /*
   2  *  ebt_redirect
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10 #include <linux/module.h>
  11 #include <net/sock.h>
  12 #include "../br_private.h"
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/x_tables.h>
  15 #include <linux/netfilter_bridge/ebtables.h>
  16 #include <linux/netfilter_bridge/ebt_redirect.h>
  17
  18 static unsigned int
  19 ebt_redirect_tg(struct sk_buff *skb, const struct xt_target_param *par)
  20 {
  21         const struct ebt_redirect_info *info = par->targinfo;
  22
  23         if (!skb_make_writable(skb, 0))
  24                 return EBT_DROP;
  25
  26         if (par->hooknum != NF_BR_BROUTING)
  27                 memcpy(eth_hdr(skb)->h_dest,
  28                        par->in->br_port->br->dev->dev_addr, ETH_ALEN);
  29         else
  30                 memcpy(eth_hdr(skb)->h_dest, par->in->dev_addr, ETH_ALEN);
  31         skb->pkt_type = PACKET_HOST;
  32         return info->target;
  33 }
  34
  35 static bool ebt_redirect_tg_check(const struct xt_tgchk_param *par)
  36 {
  37         const struct ebt_redirect_info *info = par->targinfo;
  38         unsigned int hook_mask;
  39
  40         if (BASE_CHAIN && info->target == EBT_RETURN)
  41                 return false;
  42
  43         hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
  44         if ((strcmp(par->table, "nat") != 0 ||
  45             hook_mask & ~(1 << NF_BR_PRE_ROUTING)) &&
  46             (strcmp(par->table, "broute") != 0 ||
  47             hook_mask & ~(1 << NF_BR_BROUTING)))
  48                 return false;
  49         if (INVALID_TARGET)
  50                 return false;
  51         return true;
  52 }
  53
  54 static struct xt_target ebt_redirect_tg_reg __read_mostly = {
  55         .name           = "redirect",
  56         .revision       = 0,
  57         .family         = NFPROTO_BRIDGE,
  58         .hooks          = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
  59                           (1 << NF_BR_BROUTING),
  60         .target         = ebt_redirect_tg,
  61         .checkentry     = ebt_redirect_tg_check,
  62         .targetsize     = XT_ALIGN(sizeof(struct ebt_redirect_info)),
  63         .me             = THIS_MODULE,
  64 };
  65
  66 static int __init ebt_redirect_init(void)
  67 {
  68         return xt_register_target(&ebt_redirect_tg_reg);
  69 }
  70
  71 static void __exit ebt_redirect_fini(void)
  72 {
  73         xt_unregister_target(&ebt_redirect_tg_reg);
  74 }
  75
  76 module_init(ebt_redirect_init);
  77 module_exit(ebt_redirect_fini);
  78 MODULE_DESCRIPTION("Ebtables: Packet redirection to localhost");
  79 MODULE_LICENSE("GPL");