LXR linux/net/bridge/netfilter/ebt

   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
  18static unsigned int
  19ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_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 (xt_hooknum(par) != NF_BR_BROUTING)
  27                /* rcu_read_lock()ed by nf_hook_thresh */
  28                ether_addr_copy(eth_hdr(skb)->h_dest,
  29                                br_port_get_rcu(xt_in(par))->br->dev->dev_addr);
  30        else
  31                ether_addr_copy(eth_hdr(skb)->h_dest, xt_in(par)->dev_addr);
  32        skb->pkt_type = PACKET_HOST;
  33        return info->target;
  34}
  35
  36static int ebt_redirect_tg_check(const struct xt_tgchk_param *par)
  37{
  38        const struct ebt_redirect_info *info = par->targinfo;
  39        unsigned int hook_mask;
  40
  41        if (BASE_CHAIN && info->target == EBT_RETURN)
  42                return -EINVAL;
  43
  44        hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
  45        if ((strcmp(par->table, "nat") != 0 ||
  46            hook_mask & ~(1 << NF_BR_PRE_ROUTING)) &&
  47            (strcmp(par->table, "broute") != 0 ||
  48            hook_mask & ~(1 << NF_BR_BROUTING)))
  49                return -EINVAL;
  50        if (ebt_invalid_target(info->target))
  51                return -EINVAL;
  52        return 0;
  53}
  54
  55static struct xt_target ebt_redirect_tg_reg __read_mostly = {
  56        .name           = "redirect",
  57        .revision       = 0,
  58        .family         = NFPROTO_BRIDGE,
  59        .hooks          = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
  60                          (1 << NF_BR_BROUTING),
  61        .target         = ebt_redirect_tg,
  62        .checkentry     = ebt_redirect_tg_check,
  63        .targetsize     = sizeof(struct ebt_redirect_info),
  64        .me             = THIS_MODULE,
  65};
  66
  67static int __init ebt_redirect_init(void)
  68{
  69        return xt_register_target(&ebt_redirect_tg_reg);
  70}
  71
  72static void __exit ebt_redirect_fini(void)
  73{
  74        xt_unregister_target(&ebt_redirect_tg_reg);
  75}
  76
  77module_init(ebt_redirect_init);
  78module_exit(ebt_redirect_fini);
  79MODULE_DESCRIPTION("Ebtables: Packet redirection to localhost");
  80MODULE_LICENSE("GPL");
  81