1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Kernel module to match MAC address parameters. */ 3 4 /* (C) 1999-2001 Paul `Rusty' Russell 5 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> 6 */ 7 8 #include <linux/module.h> 9 #include <linux/skbuff.h> 10 #include <linux/if_arp.h> 11 #include <linux/if_ether.h> 12 #include <linux/etherdevice.h> 13 14 #include <linux/netfilter_ipv4.h> 15 #include <linux/netfilter_ipv6.h> 16 #include <linux/netfilter/xt_mac.h> 17 #include <linux/netfilter/x_tables.h> 18 19 MODULE_LICENSE("GPL"); 20 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); 21 MODULE_DESCRIPTION("Xtables: MAC address match"); 22 MODULE_ALIAS("ipt_mac"); 23 MODULE_ALIAS("ip6t_mac"); 24 25 static bool mac_mt(const struct sk_buff *skb, struct xt_action_param *par) 26 { 27 const struct xt_mac_info *info = par->matchinfo; 28 bool ret; 29 30 if (skb->dev == NULL || skb->dev->type != ARPHRD_ETHER) 31 return false; 32 if (skb_mac_header(skb) < skb->head) 33 return false; 34 if (skb_mac_header(skb) + ETH_HLEN > skb->data) 35 return false; 36 ret = ether_addr_equal(eth_hdr(skb)->h_source, info->srcaddr); 37 ret ^= info->invert; 38 return ret; 39 } 40 41 static struct xt_match mac_mt_reg __read_mostly = { 42 .name = "mac", 43 .revision = 0, 44 .family = NFPROTO_UNSPEC, 45 .match = mac_mt, 46 .matchsize = sizeof(struct xt_mac_info), 47 .hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_IN) | 48 (1 << NF_INET_FORWARD), 49 .me = THIS_MODULE, 50 }; 51 52 static int __init mac_mt_init(void) 53 { 54 return xt_register_match(&mac_mt_reg); 55 } 56 57 static void __exit mac_mt_exit(void) 58 { 59 xt_unregister_match(&mac_mt_reg); 60 } 61 62 module_init(mac_mt_init); 63 module_exit(mac_mt_exit); 64