LXR linux/net/bridge/netfilter/ebt

   1/*
   2 *  ebt_dnat
   3 *
   4 *      Authors:
   5 *      Bart De Schuymer <bdschuym@pandora.be>
   6 *
   7 *  June, 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_nat.h>
  17
  18static unsigned int
  19ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par)
  20{
  21        const struct ebt_nat_info *info = par->targinfo;
  22        struct net_device *dev;
  23
  24        if (!skb_make_writable(skb, 0))
  25                return EBT_DROP;
  26
  27        ether_addr_copy(eth_hdr(skb)->h_dest, info->mac);
  28
  29        if (is_multicast_ether_addr(info->mac)) {
  30                if (is_broadcast_ether_addr(info->mac))
  31                        skb->pkt_type = PACKET_BROADCAST;
  32                else
  33                        skb->pkt_type = PACKET_MULTICAST;
  34        } else {
  35                if (xt_hooknum(par) != NF_BR_BROUTING)
  36                        dev = br_port_get_rcu(xt_in(par))->br->dev;
  37                else
  38                        dev = xt_in(par);
  39
  40                if (ether_addr_equal(info->mac, dev->dev_addr))
  41                        skb->pkt_type = PACKET_HOST;
  42                else
  43                        skb->pkt_type = PACKET_OTHERHOST;
  44        }
  45
  46        return info->target;
  47}
  48
  49static int ebt_dnat_tg_check(const struct xt_tgchk_param *par)
  50{
  51        const struct ebt_nat_info *info = par->targinfo;
  52        unsigned int hook_mask;
  53
  54        if (BASE_CHAIN && info->target == EBT_RETURN)
  55                return -EINVAL;
  56
  57        hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
  58        if ((strcmp(par->table, "nat") != 0 ||
  59            (hook_mask & ~((1 << NF_BR_PRE_ROUTING) |
  60            (1 << NF_BR_LOCAL_OUT)))) &&
  61            (strcmp(par->table, "broute") != 0 ||
  62            hook_mask & ~(1 << NF_BR_BROUTING)))
  63                return -EINVAL;
  64        if (ebt_invalid_target(info->target))
  65                return -EINVAL;
  66        return 0;
  67}
  68
  69static struct xt_target ebt_dnat_tg_reg __read_mostly = {
  70        .name           = "dnat",
  71        .revision       = 0,
  72        .family         = NFPROTO_BRIDGE,
  73        .hooks          = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
  74                          (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING),
  75        .target         = ebt_dnat_tg,
  76        .checkentry     = ebt_dnat_tg_check,
  77        .targetsize     = sizeof(struct ebt_nat_info),
  78        .me             = THIS_MODULE,
  79};
  80
  81static int __init ebt_dnat_init(void)
  82{
  83        return xt_register_target(&ebt_dnat_tg_reg);
  84}
  85
  86static void __exit ebt_dnat_fini(void)
  87{
  88        xt_unregister_target(&ebt_dnat_tg_reg);
  89}
  90
  91module_init(ebt_dnat_init);
  92module_exit(ebt_dnat_fini);
  93MODULE_DESCRIPTION("Ebtables: Destination MAC address translation");
  94MODULE_LICENSE("GPL");
  95