1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ebt_dnat 4 * 5 * Authors: 6 * Bart De Schuymer <bdschuym@pandora.be> 7 * 8 * June, 2002 9 * 10 */ 11 #include <linux/module.h> 12 #include <net/sock.h> 13 #include "../br_private.h" 14 #include <linux/netfilter.h> 15 #include <linux/netfilter/x_tables.h> 16 #include <linux/netfilter_bridge/ebtables.h> 17 #include <linux/netfilter_bridge/ebt_nat.h> 18 19 static unsigned int 20 ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par) 21 { 22 const struct ebt_nat_info *info = par->targinfo; 23 struct net_device *dev; 24 25 if (skb_ensure_writable(skb, ETH_ALEN)) 26 return EBT_DROP; 27 28 ether_addr_copy(eth_hdr(skb)->h_dest, info->mac); 29 30 if (is_multicast_ether_addr(info->mac)) { 31 if (is_broadcast_ether_addr(info->mac)) 32 skb->pkt_type = PACKET_BROADCAST; 33 else 34 skb->pkt_type = PACKET_MULTICAST; 35 } else { 36 if (xt_hooknum(par) != NF_BR_BROUTING) 37 dev = br_port_get_rcu(xt_in(par))->br->dev; 38 else 39 dev = xt_in(par); 40 41 if (ether_addr_equal(info->mac, dev->dev_addr)) 42 skb->pkt_type = PACKET_HOST; 43 else 44 skb->pkt_type = PACKET_OTHERHOST; 45 } 46 47 return info->target; 48 } 49 50 static int ebt_dnat_tg_check(const struct xt_tgchk_param *par) 51 { 52 const struct ebt_nat_info *info = par->targinfo; 53 unsigned int hook_mask; 54 55 if (BASE_CHAIN && info->target == EBT_RETURN) 56 return -EINVAL; 57 58 hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS); 59 if ((strcmp(par->table, "nat") != 0 || 60 (hook_mask & ~((1 << NF_BR_PRE_ROUTING) | 61 (1 << NF_BR_LOCAL_OUT)))) && 62 (strcmp(par->table, "broute") != 0 || 63 hook_mask & ~(1 << NF_BR_BROUTING))) 64 return -EINVAL; 65 if (ebt_invalid_target(info->target)) 66 return -EINVAL; 67 return 0; 68 } 69 70 static struct xt_target ebt_dnat_tg_reg __read_mostly = { 71 .name = "dnat", 72 .revision = 0, 73 .family = NFPROTO_BRIDGE, 74 .hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) | 75 (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING), 76 .target = ebt_dnat_tg, 77 .checkentry = ebt_dnat_tg_check, 78 .targetsize = sizeof(struct ebt_nat_info), 79 .me = THIS_MODULE, 80 }; 81 82 static int __init ebt_dnat_init(void) 83 { 84 return xt_register_target(&ebt_dnat_tg_reg); 85 } 86 87 static void __exit ebt_dnat_fini(void) 88 { 89 xt_unregister_target(&ebt_dnat_tg_reg); 90 } 91 92 module_init(ebt_dnat_init); 93 module_exit(ebt_dnat_fini); 94 MODULE_DESCRIPTION("Ebtables: Destination MAC address translation"); 95 MODULE_LICENSE("GPL"); 96