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 <linux/netfilter.h> 13 #include <linux/netfilter/x_tables.h> 14 #include <linux/netfilter_bridge/ebtables.h> 15 #include <linux/netfilter_bridge/ebt_nat.h> 16 17 static unsigned int 18 ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par) 19 { 20 const struct ebt_nat_info *info = par->targinfo; 21 22 if (!skb_make_writable(skb, 0)) 23 return EBT_DROP; 24 25 memcpy(eth_hdr(skb)->h_dest, info->mac, ETH_ALEN); 26 return info->target; 27 } 28 29 static int ebt_dnat_tg_check(const struct xt_tgchk_param *par) 30 { 31 const struct ebt_nat_info *info = par->targinfo; 32 unsigned int hook_mask; 33 34 if (BASE_CHAIN && info->target == EBT_RETURN) 35 return -EINVAL; 36 37 hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS); 38 if ((strcmp(par->table, "nat") != 0 || 39 (hook_mask & ~((1 << NF_BR_PRE_ROUTING) | 40 (1 << NF_BR_LOCAL_OUT)))) && 41 (strcmp(par->table, "broute") != 0 || 42 hook_mask & ~(1 << NF_BR_BROUTING))) 43 return -EINVAL; 44 if (INVALID_TARGET) 45 return -EINVAL; 46 return 0; 47 } 48 49 static struct xt_target ebt_dnat_tg_reg __read_mostly = { 50 .name = "dnat", 51 .revision = 0, 52 .family = NFPROTO_BRIDGE, 53 .hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) | 54 (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING), 55 .target = ebt_dnat_tg, 56 .checkentry = ebt_dnat_tg_check, 57 .targetsize = sizeof(struct ebt_nat_info), 58 .me = THIS_MODULE, 59 }; 60 61 static int __init ebt_dnat_init(void) 62 { 63 return xt_register_target(&ebt_dnat_tg_reg); 64 } 65 66 static void __exit ebt_dnat_fini(void) 67 { 68 xt_unregister_target(&ebt_dnat_tg_reg); 69 } 70 71 module_init(ebt_dnat_init); 72 module_exit(ebt_dnat_fini); 73 MODULE_DESCRIPTION("Ebtables: Destination MAC address translation"); 74 MODULE_LICENSE("GPL"); 75