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/* This kernel module is used to modify the connection mark values, or
* to optionally restore the skb nfmark from the connection mark
*
* Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com>
* by Henrik Nordstrom <hno@marasystems.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/checksum.h>
MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>");
MODULE_DESCRIPTION("IP tables CONNMARK matching module");
MODULE_LICENSE("GPL");
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_CONNMARK.h>
#include <linux/netfilter_ipv4/ip_conntrack.h>
static unsigned int
target(struct sk_buff **pskb,
const struct net_device *in,
const struct net_device *out,
unsigned int hooknum,
const void *targinfo,
void *userinfo)
{
const struct ipt_connmark_target_info *markinfo = targinfo;
u_int32_t diff;
u_int32_t nfmark;
u_int32_t newmark;
enum ip_conntrack_info ctinfo;
struct ip_conntrack *ct = ip_conntrack_get((*pskb), &ctinfo);
if (ct) {
switch(markinfo->mode) {
case IPT_CONNMARK_SET:
newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
if (newmark != ct->mark)
ct->mark = newmark;
break;
case IPT_CONNMARK_SAVE:
newmark = (ct->mark & ~markinfo->mask) | ((*pskb)->nfmark & markinfo->mask);
if (ct->mark != newmark)
ct->mark = newmark;
break;
case IPT_CONNMARK_RESTORE:
nfmark = (*pskb)->nfmark;
diff = (ct->mark ^ nfmark) & markinfo->mask;
if (diff != 0)
(*pskb)->nfmark = nfmark ^ diff;
break;
}
}
return IPT_CONTINUE;
}
static int
checkentry(const char *tablename,
const struct ipt_entry *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hook_mask)
{
struct ipt_connmark_target_info *matchinfo = targinfo;
if (targinfosize != IPT_ALIGN(sizeof(struct ipt_connmark_target_info))) {
printk(KERN_WARNING "CONNMARK: targinfosize %u != %Zu\n",
targinfosize,
IPT_ALIGN(sizeof(struct ipt_connmark_target_info)));
return 0;
}
if (matchinfo->mode == IPT_CONNMARK_RESTORE) {
if (strcmp(tablename, "mangle") != 0) {
printk(KERN_WARNING "CONNMARK: restore can only be called from \"mangle\" table, not \"%s\"\n", tablename);
return 0;
}
}
if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
return 0;
}
return 1;
}
static struct ipt_target ipt_connmark_reg = {
.name = "CONNMARK",
.target = &target,
.checkentry = &checkentry,
.me = THIS_MODULE
};
static int __init init(void)
{
return ipt_register_target(&ipt_connmark_reg);
}
static void __exit fini(void)
{
ipt_unregister_target(&ipt_connmark_reg);
}
module_init(init);
module_exit(fini);
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