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xt_dscp.c
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xt_dscp.c
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/* IP tables module for matching the value of the IPv4/IPv6 DSCP field
*
* (C) 2002 by Harald Welte <[email protected]>
*
* 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/x_tables.h>
#include <linux/netfilter/xt_dscp.h>
#include <linux/netfilter_ipv4/ipt_tos.h>
MODULE_AUTHOR("Harald Welte <[email protected]>");
MODULE_DESCRIPTION("Xtables: DSCP/TOS field match");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_dscp");
MODULE_ALIAS("ip6t_dscp");
MODULE_ALIAS("ipt_tos");
MODULE_ALIAS("ip6t_tos");
static bool
dscp_mt(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
dscp_mt6(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
dscp_mt_check(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 bool tos_mt_v0(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 ipt_tos_info *info = matchinfo;
return (ip_hdr(skb)->tos == info->tos) ^ info->invert;
}
static bool tos_mt(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_tos_match_info *info = matchinfo;
if (match->family == AF_INET)
return ((ip_hdr(skb)->tos & info->tos_mask) ==
info->tos_value) ^ !!info->invert;
else
return ((ipv6_get_dsfield(ipv6_hdr(skb)) & info->tos_mask) ==
info->tos_value) ^ !!info->invert;
}
static struct xt_match dscp_mt_reg[] __read_mostly = {
{
.name = "dscp",
.family = AF_INET,
.checkentry = dscp_mt_check,
.match = dscp_mt,
.matchsize = sizeof(struct xt_dscp_info),
.me = THIS_MODULE,
},
{
.name = "dscp",
.family = AF_INET6,
.checkentry = dscp_mt_check,
.match = dscp_mt6,
.matchsize = sizeof(struct xt_dscp_info),
.me = THIS_MODULE,
},
{
.name = "tos",
.revision = 0,
.family = AF_INET,
.match = tos_mt_v0,
.matchsize = sizeof(struct ipt_tos_info),
.me = THIS_MODULE,
},
{
.name = "tos",
.revision = 1,
.family = AF_INET,
.match = tos_mt,
.matchsize = sizeof(struct xt_tos_match_info),
.me = THIS_MODULE,
},
{
.name = "tos",
.revision = 1,
.family = AF_INET6,
.match = tos_mt,
.matchsize = sizeof(struct xt_tos_match_info),
.me = THIS_MODULE,
},
};
static int __init dscp_mt_init(void)
{
return xt_register_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
}
static void __exit dscp_mt_exit(void)
{
xt_unregister_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
}
module_init(dscp_mt_init);
module_exit(dscp_mt_exit);