net/bridge/netfilter/ebt_redirect.c

   1 /*
   2  *  ebt_redirect
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10
  11 #include <linux/netfilter_bridge/ebtables.h>
  12 #include <linux/netfilter_bridge/ebt_redirect.h>
  13 #include <linux/module.h>
  14 #include <net/sock.h>
  15 #include "../br_private.h"
  16
  17 static int ebt_target_redirect(struct sk_buff **pskb, unsigned int hooknr,
  18    const struct net_device *in, const struct net_device *out,
  19    const void *data, unsigned int datalen)
  20 {
  21         struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
  22
  23         if (skb_shared(*pskb) || skb_cloned(*pskb)) {
  24                 struct sk_buff *nskb;
  25
  26                 nskb = skb_copy(*pskb, GFP_ATOMIC);
  27                 if (!nskb)
  28                         return NF_DROP;
  29                 if ((*pskb)->sk)
  30                         skb_set_owner_w(nskb, (*pskb)->sk);
  31                 kfree_skb(*pskb);
  32                 *pskb = nskb;
  33         }
  34         if (hooknr != NF_BR_BROUTING)
  35                 memcpy((**pskb).mac.ethernet->h_dest,
  36                    in->br_port->br->dev->dev_addr, ETH_ALEN);
  37         else
  38                 memcpy((**pskb).mac.ethernet->h_dest,
  39                    in->dev_addr, ETH_ALEN);
  40         (*pskb)->pkt_type = PACKET_HOST;
  41         return info->target;
  42 }
  43
  44 static int ebt_target_redirect_check(const char *tablename, unsigned int hookmask,
  45    const struct ebt_entry *e, void *data, unsigned int datalen)
  46 {
  47         struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
  48
  49         if (datalen != EBT_ALIGN(sizeof(struct ebt_redirect_info)))
  50                 return -EINVAL;
  51         if (BASE_CHAIN && info->target == EBT_RETURN)
  52                 return -EINVAL;
  53         CLEAR_BASE_CHAIN_BIT;
  54         if ( (strcmp(tablename, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING)) &&
  55              (strcmp(tablename, "broute") || hookmask & ~(1 << NF_BR_BROUTING)) )
  56                 return -EINVAL;
  57         if (INVALID_TARGET)
  58                 return -EINVAL;
  59         return 0;
  60 }
  61
  62 static struct ebt_target redirect_target =
  63 {
  64         .name           = EBT_REDIRECT_TARGET,
  65         .target         = ebt_target_redirect,
  66         .check          = ebt_target_redirect_check,
  67         .me             = THIS_MODULE,
  68 };
  69
  70 static int __init init(void)
  71 {
  72         return ebt_register_target(&redirect_target);
  73 }
  74
  75 static void __exit fini(void)
  76 {
  77         ebt_unregister_target(&redirect_target);
  78 }
  79
  80 module_init(init);
  81 module_exit(fini);
  82 MODULE_LICENSE("GPL");