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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@marasystems.com>");
MODULE_DESCRIPTION("IP tables CONNMARK matching module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_CONNMARK");
MODULE_ALIAS("ip6t_CONNMARK");
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_CONNMARK.h>
#include <net/netfilter/nf_conntrack_ecache.h>
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_connmark_target_info *markinfo = targinfo;
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
u_int32_t diff;
u_int32_t mark;
u_int32_t newmark;
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
switch(markinfo->mode) {
case XT_CONNMARK_SET:
newmark = (ct->mark & ~markinfo->mask) | markinfo->mark;
if (newmark != ct->mark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, skb);
}
break;
case XT_CONNMARK_SAVE:
newmark = (ct->mark & ~markinfo->mask) |
(skb->mark & markinfo->mask);
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, skb);
}
break;
case XT_CONNMARK_RESTORE:
mark = skb->mark;
diff = (ct->mark ^ mark) & markinfo->mask;
skb->mark = mark ^ diff;
break;
}
}
return XT_CONTINUE;
}
static bool
checkentry(const char *tablename,
const void *entry,
const struct xt_target *target,
void *targinfo,
unsigned int hook_mask)
{
const struct xt_connmark_target_info *matchinfo = targinfo;
if (nf_ct_l3proto_try_module_get(target->family) < 0) {
printk(KERN_WARNING "can't load conntrack support for "
"proto=%d\n", target->family);
return false;
}
if (matchinfo->mode == XT_CONNMARK_RESTORE) {
if (strcmp(tablename, "mangle") != 0) {
printk(KERN_WARNING "CONNMARK: restore can only be "
"called from \"mangle\" table, not \"%s\"\n",
tablename);
return false;
}
}
if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) {
printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n");
return false;
}
return true;
}
static void
destroy(const struct xt_target *target, void *targinfo)
{
nf_ct_l3proto_module_put(target->family);
}
#ifdef CONFIG_COMPAT
struct compat_xt_connmark_target_info {
compat_ulong_t mark, mask;
u_int8_t mode;
u_int8_t __pad1;
u_int16_t __pad2;
};
static void compat_from_user(void *dst, void *src)
{
const struct compat_xt_connmark_target_info *cm = src;
struct xt_connmark_target_info m = {
.mark = cm->mark,
.mask = cm->mask,
.mode = cm->mode,
};
memcpy(dst, &m, sizeof(m));
}
static int compat_to_user(void __user *dst, void *src)
{
const struct xt_connmark_target_info *m = src;
struct compat_xt_connmark_target_info cm = {
.mark = m->mark,
.mask = m->mask,
.mode = m->mode,
};
return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0;
}
#endif /* CONFIG_COMPAT */
static struct xt_target xt_connmark_target[] __read_mostly = {
{
.name = "CONNMARK",
.family = AF_INET,
.checkentry = checkentry,
.destroy = destroy,
.target = target,
.targetsize = sizeof(struct xt_connmark_target_info),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_connmark_target_info),
.compat_from_user = compat_from_user,
.compat_to_user = compat_to_user,
#endif
.me = THIS_MODULE
},
{
.name = "CONNMARK",
.family = AF_INET6,
.checkentry = checkentry,
.destroy = destroy,
.target = target,
.targetsize = sizeof(struct xt_connmark_target_info),
.me = THIS_MODULE
},
};
static int __init xt_connmark_init(void)
{
return xt_register_targets(xt_connmark_target,
ARRAY_SIZE(xt_connmark_target));
}
static void __exit xt_connmark_fini(void)
{
xt_unregister_targets(xt_connmark_target,
ARRAY_SIZE(xt_connmark_target));
}
module_init(xt_connmark_init);
module_exit(xt_connmark_fini);
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