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/* IP tables module for matching the value of the IPv4/IPv6 DSCP field
*
* (C) 2002 by Harald Welte <laforge@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/ip.h>
#include <linux/ipv6.h>
#include <net/dsfield.h>
#include <linux/netfilter/xt_dscp.h>
#include <linux/netfilter/x_tables.h>
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("x_tables DSCP matching module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_dscp");
MODULE_ALIAS("ip6t_dscp");
static bool match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
bool *hotdrop)
{
const struct xt_dscp_info *info = matchinfo;
u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
return (dscp == info->dscp) ^ !!info->invert;
}
static bool match6(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct xt_match *match,
const void *matchinfo,
int offset,
unsigned int protoff,
bool *hotdrop)
{
const struct xt_dscp_info *info = matchinfo;
u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
return (dscp == info->dscp) ^ !!info->invert;
}
static bool checkentry(const char *tablename,
const void *info,
const struct xt_match *match,
void *matchinfo,
unsigned int hook_mask)
{
const u_int8_t dscp = ((struct xt_dscp_info *)matchinfo)->dscp;
if (dscp > XT_DSCP_MAX) {
printk(KERN_ERR "xt_dscp: dscp %x out of range\n", dscp);
return false;
}
return true;
}
static struct xt_match xt_dscp_match[] __read_mostly = {
{
.name = "dscp",
.family = AF_INET,
.checkentry = checkentry,
.match = match,
.matchsize = sizeof(struct xt_dscp_info),
.me = THIS_MODULE,
},
{
.name = "dscp",
.family = AF_INET6,
.checkentry = checkentry,
.match = match6,
.matchsize = sizeof(struct xt_dscp_info),
.me = THIS_MODULE,
},
};
static int __init xt_dscp_match_init(void)
{
return xt_register_matches(xt_dscp_match, ARRAY_SIZE(xt_dscp_match));
}
static void __exit xt_dscp_match_fini(void)
{
xt_unregister_matches(xt_dscp_match, ARRAY_SIZE(xt_dscp_match));
}
module_init(xt_dscp_match_init);
module_exit(xt_dscp_match_fini);
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