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/* IP tables module for matching the value of the IPv4 DSCP field
 *
 * ipt_dscp.c,v 1.3 2002/08/05 19:00:21 laforge Exp
 *
 * (C) 2002 by Harald Welte <laforge@gnumonks.org>
 *
 * This software is distributed under the terms  GNU GPL
 */
 
#include <linux/module.h>
#include <linux/skbuff.h>
 
#include <linux/netfilter_ipv4/ipt_dscp.h>
#include <linux/netfilter_ipv4/ip_tables.h>
 
MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
MODULE_DESCRIPTION("IP tables DSCP matching module");
MODULE_LICENSE("GPL");
 
static int match(const struct sk_buff *skb, const struct net_device *in,
		 const struct net_device *out, const void *matchinfo,
		 int offset, const void *hdr, u_int16_t datalen,
		 int *hotdrop)
{
	const struct ipt_dscp_info *info = matchinfo;
	const struct iphdr *iph = skb->nh.iph;
 
	u_int8_t sh_dscp = ((info->dscp << IPT_DSCP_SHIFT) & IPT_DSCP_MASK);
 
	return ((iph->tos&IPT_DSCP_MASK) == sh_dscp) ^ info->invert;
}
 
static int checkentry(const char *tablename, const struct ipt_ip *ip,
		      void *matchinfo, unsigned int matchsize,
		      unsigned int hook_mask)
{
	if (matchsize != IPT_ALIGN(sizeof(struct ipt_dscp_info)))
		return 0;
 
	return 1;
}
 
static struct ipt_match dscp_match = { { NULL, NULL }, "dscp", &match,
		&checkentry, NULL, THIS_MODULE };
 
static int __init init(void)
{
	return ipt_register_match(&dscp_match);
}
 
static void __exit fini(void)
{
	ipt_unregister_match(&dscp_match);
 
}
 
module_init(init);
module_exit(fini);