1 /* 2 * ebt_redirect 3 * 4 * Authors: 5 * Bart De Schuymer <bdschuym@pandora.be> 6 * 7 * April, 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_redirect.h> 17 18 static unsigned int 19 ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par) 20 { 21 const struct ebt_redirect_info *info = par->targinfo; 22 23 if (!skb_make_writable(skb, 0)) 24 return EBT_DROP; 25 26 if (xt_hooknum(par) != NF_BR_BROUTING) 27 /* rcu_read_lock()ed by nf_hook_thresh */ 28 ether_addr_copy(eth_hdr(skb)->h_dest, 29 br_port_get_rcu(xt_in(par))->br->dev->dev_addr); 30 else 31 ether_addr_copy(eth_hdr(skb)->h_dest, xt_in(par)->dev_addr); 32 skb->pkt_type = PACKET_HOST; 33 return info->target; 34 } 35 36 static int ebt_redirect_tg_check(const struct xt_tgchk_param *par) 37 { 38 const struct ebt_redirect_info *info = par->targinfo; 39 unsigned int hook_mask; 40 41 if (BASE_CHAIN && info->target == EBT_RETURN) 42 return -EINVAL; 43 44 hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS); 45 if ((strcmp(par->table, "nat") != 0 || 46 hook_mask & ~(1 << NF_BR_PRE_ROUTING)) && 47 (strcmp(par->table, "broute") != 0 || 48 hook_mask & ~(1 << NF_BR_BROUTING))) 49 return -EINVAL; 50 if (INVALID_TARGET) 51 return -EINVAL; 52 return 0; 53 } 54 55 static struct xt_target ebt_redirect_tg_reg __read_mostly = { 56 .name = "redirect", 57 .revision = 0, 58 .family = NFPROTO_BRIDGE, 59 .hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) | 60 (1 << NF_BR_BROUTING), 61 .target = ebt_redirect_tg, 62 .checkentry = ebt_redirect_tg_check, 63 .targetsize = sizeof(struct ebt_redirect_info), 64 .me = THIS_MODULE, 65 }; 66 67 static int __init ebt_redirect_init(void) 68 { 69 return xt_register_target(&ebt_redirect_tg_reg); 70 } 71 72 static void __exit ebt_redirect_fini(void) 73 { 74 xt_unregister_target(&ebt_redirect_tg_reg); 75 } 76 77 module_init(ebt_redirect_init); 78 module_exit(ebt_redirect_fini); 79 MODULE_DESCRIPTION("Ebtables: Packet redirection to localhost"); 80 MODULE_LICENSE("GPL"); 81