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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>
#include <linux/netfilter_ipv4/ipt_TOS.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");
MODULE_ALIAS("ipt_TOS");
MODULE_ALIAS("ip6t_TOS");
static unsigned int
dscp_tg(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
dscp_tg6(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
dscp_tg_check(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 unsigned int
tos_tg_v0(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 ipt_tos_target_info *info = targinfo;
struct iphdr *iph = ip_hdr(skb);
u_int8_t oldtos;
if ((iph->tos & IPTOS_TOS_MASK) != info->tos) {
if (!skb_make_writable(skb, sizeof(struct iphdr)))
return NF_DROP;
iph = ip_hdr(skb);
oldtos = iph->tos;
iph->tos = (iph->tos & IPTOS_PREC_MASK) | info->tos;
csum_replace2(&iph->check, htons(oldtos), htons(iph->tos));
}
return XT_CONTINUE;
}
static bool
tos_tg_check_v0(const char *tablename, const void *e_void,
const struct xt_target *target, void *targinfo,
unsigned int hook_mask)
{
const u_int8_t tos = ((struct ipt_tos_target_info *)targinfo)->tos;
if (tos != IPTOS_LOWDELAY && tos != IPTOS_THROUGHPUT &&
tos != IPTOS_RELIABILITY && tos != IPTOS_MINCOST &&
tos != IPTOS_NORMALSVC) {
printk(KERN_WARNING "TOS: bad tos value %#x\n", tos);
return false;
}
return true;
}
static unsigned int
tos_tg(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_tos_target_info *info = targinfo;
struct iphdr *iph = ip_hdr(skb);
u_int8_t orig, nv;
orig = ipv4_get_dsfield(iph);
nv = (orig & info->tos_mask) ^ info->tos_value;
if (orig != nv) {
if (!skb_make_writable(skb, sizeof(struct iphdr)))
return NF_DROP;
iph = ip_hdr(skb);
ipv4_change_dsfield(iph, ~0, nv);
}
return XT_CONTINUE;
}
static unsigned int
tos_tg6(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_tos_target_info *info = targinfo;
struct ipv6hdr *iph = ipv6_hdr(skb);
u_int8_t orig, nv;
orig = ipv6_get_dsfield(iph);
nv = (orig & info->tos_mask) ^ info->tos_value;
if (orig != nv) {
if (!skb_make_writable(skb, sizeof(struct iphdr)))
return NF_DROP;
iph = ipv6_hdr(skb);
ipv6_change_dsfield(iph, ~0, nv);
}
return XT_CONTINUE;
}
static struct xt_target dscp_tg_reg[] __read_mostly = {
{
.name = "DSCP",
.family = AF_INET,
.checkentry = dscp_tg_check,
.target = dscp_tg,
.targetsize = sizeof(struct xt_DSCP_info),
.table = "mangle",
.me = THIS_MODULE,
},
{
.name = "DSCP",
.family = AF_INET6,
.checkentry = dscp_tg_check,
.target = dscp_tg6,
.targetsize = sizeof(struct xt_DSCP_info),
.table = "mangle",
.me = THIS_MODULE,
},
{
.name = "TOS",
.revision = 0,
.family = AF_INET,
.table = "mangle",
.target = tos_tg_v0,
.targetsize = sizeof(struct ipt_tos_target_info),
.checkentry = tos_tg_check_v0,
.me = THIS_MODULE,
},
{
.name = "TOS",
.revision = 1,
.family = AF_INET,
.table = "mangle",
.target = tos_tg,
.targetsize = sizeof(struct xt_tos_target_info),
.me = THIS_MODULE,
},
{
.name = "TOS",
.revision = 1,
.family = AF_INET6,
.table = "mangle",
.target = tos_tg6,
.targetsize = sizeof(struct xt_tos_target_info),
.me = THIS_MODULE,
},
};
static int __init dscp_tg_init(void)
{
return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg));
}
static void __exit dscp_tg_exit(void)
{
xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg));
}
module_init(dscp_tg_init);
module_exit(dscp_tg_exit);
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