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 18 static unsigned int 19 ebt_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 49 static 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 69 static 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 81 static int __init ebt_dnat_init(void) 82 { 83 return xt_register_target(&ebt_dnat_tg_reg); 84 } 85 86 static void __exit ebt_dnat_fini(void) 87 { 88 xt_unregister_target(&ebt_dnat_tg_reg); 89 } 90 91 module_init(ebt_dnat_init); 92 module_exit(ebt_dnat_fini); 93 MODULE_DESCRIPTION("Ebtables: Destination MAC address translation"); 94 MODULE_LICENSE("GPL"); 95