/* Kernel module to match MAC address parameters. *//* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/module.h>#include <linux/skbuff.h>#include <linux/if_ether.h>#include <linux/netfilter_ipv4/ipt_mac.h>#include <linux/netfilter_ipv4/ip_tables.h>MODULE_LICENSE("GPL");MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");MODULE_DESCRIPTION("iptables mac matching module");static intmatch(const struct sk_buff *skb,      const struct net_device *in,      const struct net_device *out,      const void *matchinfo,      int offset,      int *hotdrop){    const struct ipt_mac_info *info = matchinfo;    /* Is mac pointer valid? */    return (skb->mac.raw >= skb->head	    && (skb->mac.raw + ETH_HLEN) <= skb->data	    /* If so, compare... */	    && ((memcmp(skb->mac.ethernet->h_source, info->srcaddr, ETH_ALEN)		== 0) ^ info->invert));}static intipt_mac_checkentry(const char *tablename,		   const struct ipt_ip *ip,		   void *matchinfo,		   unsigned int matchsize,		   unsigned int hook_mask){	/* FORWARD isn't always valid, but it's nice to be able to do --RR */	if (hook_mask	    & ~((1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_LOCAL_IN)		| (1 << NF_IP_FORWARD))) {		printk("ipt_mac: only valid for PRE_ROUTING, LOCAL_IN or FORWARD.\n");		return 0;	}	if (matchsize != IPT_ALIGN(sizeof(struct ipt_mac_info)))		return 0;	return 1;}static struct ipt_match mac_match = {	.name		= "mac",	.match		= &match,	.checkentry	= &ipt_mac_checkentry,	.me		= THIS_MODULE,};static int __init init(void){	return ipt_register_match(&mac_match);}static void __exit fini(void){	ipt_unregister_match(&mac_match);}module_init(init);module_exit(fini);