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/* x_tables module for setting the IPv4/IPv6 DSCP field, Version 1.8
*
* (C) 2002 by Harald Welte <laforge@netfilter.org>
* based on ipt_FTOS.c (C) 2000 by Matthew G. Marsh <mgm@paktronix.com>
*
* 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.
*
* See RFC2474 for a description of the DSCP field within the IP Header.
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <net/dsfield.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_DSCP.h>
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("x_tables DSCP modification module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_DSCP");
MODULE_ALIAS("ip6t_DSCP");
static unsigned int target(struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const struct xt_target *target,
const void *targinfo)
{
const struct xt_DSCP_info *dinfo = targinfo;
u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) {
if (!skb_make_writable(skb, sizeof(struct iphdr)))
return NF_DROP;
ipv4_change_dsfield(ip_hdr(skb), (__u8)(~XT_DSCP_MASK),
dinfo->dscp << XT_DSCP_SHIFT);
}
return XT_CONTINUE;
}
static unsigned int target6(struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const struct xt_target *target,
const void *targinfo)
{
const struct xt_DSCP_info *dinfo = targinfo;
u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
if (dscp != dinfo->dscp) {
if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
return NF_DROP;
ipv6_change_dsfield(ipv6_hdr(skb), (__u8)(~XT_DSCP_MASK),
dinfo->dscp << XT_DSCP_SHIFT);
}
return XT_CONTINUE;
}
static bool checkentry(const char *tablename,
const void *e_void,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
{
const u_int8_t dscp = ((struct xt_DSCP_info *)targinfo)->dscp;
if (dscp > XT_DSCP_MAX) {
printk(KERN_WARNING "DSCP: dscp %x out of range\n", dscp);
return false;
}
return true;
}
static struct xt_target xt_dscp_target[] __read_mostly = {
{
.name = "DSCP",
.family = AF_INET,
.checkentry = checkentry,
.target = target,
.targetsize = sizeof(struct xt_DSCP_info),
.table = "mangle",
.me = THIS_MODULE,
},
{
.name = "DSCP",
.family = AF_INET6,
.checkentry = checkentry,
.target = target6,
.targetsize = sizeof(struct xt_DSCP_info),
.table = "mangle",
.me = THIS_MODULE,
},
};
static int __init xt_dscp_target_init(void)
{
return xt_register_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target));
}
static void __exit xt_dscp_target_fini(void)
{
xt_unregister_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target));
}
module_init(xt_dscp_target_init);
module_exit(xt_dscp_target_fini);
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