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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* xt_connmark - Netfilter module to operate on connection marks
*
* Copyright (C) 2002,2004 MARA Systems AB <https://www.marasystems.com>
* by Henrik Nordstrom <hno@marasystems.com>
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
* Jan Engelhardt <jengelh@medozas.de>
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_connmark.h>
MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>");
MODULE_DESCRIPTION("Xtables: connection mark operations");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_CONNMARK");
MODULE_ALIAS("ip6t_CONNMARK");
MODULE_ALIAS("ipt_connmark");
MODULE_ALIAS("ip6t_connmark");
static unsigned int
connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info)
{
enum ip_conntrack_info ctinfo;
u_int32_t new_targetmark;
struct nf_conn *ct;
u_int32_t newmark;
u_int32_t oldmark;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
return XT_CONTINUE;
switch (info->mode) {
case XT_CONNMARK_SET:
oldmark = READ_ONCE(ct->mark);
newmark = (oldmark & ~info->ctmask) ^ info->ctmark;
if (info->shift_dir == D_SHIFT_RIGHT)
newmark >>= info->shift_bits;
else
newmark <<= info->shift_bits;
if (READ_ONCE(ct->mark) != newmark) {
WRITE_ONCE(ct->mark, newmark);
nf_conntrack_event_cache(IPCT_MARK, ct);
}
break;
case XT_CONNMARK_SAVE:
new_targetmark = (skb->mark & info->nfmask);
if (info->shift_dir == D_SHIFT_RIGHT)
new_targetmark >>= info->shift_bits;
else
new_targetmark <<= info->shift_bits;
newmark = (READ_ONCE(ct->mark) & ~info->ctmask) ^
new_targetmark;
if (READ_ONCE(ct->mark) != newmark) {
WRITE_ONCE(ct->mark, newmark);
nf_conntrack_event_cache(IPCT_MARK, ct);
}
break;
case XT_CONNMARK_RESTORE:
new_targetmark = (READ_ONCE(ct->mark) & info->ctmask);
if (info->shift_dir == D_SHIFT_RIGHT)
new_targetmark >>= info->shift_bits;
else
new_targetmark <<= info->shift_bits;
newmark = (skb->mark & ~info->nfmask) ^
new_targetmark;
skb->mark = newmark;
break;
}
return XT_CONTINUE;
}
static unsigned int
connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_connmark_tginfo1 *info = par->targinfo;
const struct xt_connmark_tginfo2 info2 = {
.ctmark = info->ctmark,
.ctmask = info->ctmask,
.nfmask = info->nfmask,
.mode = info->mode,
};
return connmark_tg_shift(skb, &info2);
}
static unsigned int
connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_connmark_tginfo2 *info = par->targinfo;
return connmark_tg_shift(skb, info);
}
static int connmark_tg_check(const struct xt_tgchk_param *par)
{
int ret;
ret = nf_ct_netns_get(par->net, par->family);
if (ret < 0)
pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
par->family);
return ret;
}
static void connmark_tg_destroy(const struct xt_tgdtor_param *par)
{
nf_ct_netns_put(par->net, par->family);
}
static bool
connmark_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
const struct xt_connmark_mtinfo1 *info = par->matchinfo;
enum ip_conntrack_info ctinfo;
const struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
return false;
return ((READ_ONCE(ct->mark) & info->mask) == info->mark) ^ info->invert;
}
static int connmark_mt_check(const struct xt_mtchk_param *par)
{
int ret;
ret = nf_ct_netns_get(par->net, par->family);
if (ret < 0)
pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
par->family);
return ret;
}
static void connmark_mt_destroy(const struct xt_mtdtor_param *par)
{
nf_ct_netns_put(par->net, par->family);
}
static struct xt_target connmark_tg_reg[] __read_mostly = {
{
.name = "CONNMARK",
.revision = 1,
.family = NFPROTO_UNSPEC,
.checkentry = connmark_tg_check,
.target = connmark_tg,
.targetsize = sizeof(struct xt_connmark_tginfo1),
.destroy = connmark_tg_destroy,
.me = THIS_MODULE,
},
{
.name = "CONNMARK",
.revision = 2,
.family = NFPROTO_UNSPEC,
.checkentry = connmark_tg_check,
.target = connmark_tg_v2,
.targetsize = sizeof(struct xt_connmark_tginfo2),
.destroy = connmark_tg_destroy,
.me = THIS_MODULE,
}
};
static struct xt_match connmark_mt_reg __read_mostly = {
.name = "connmark",
.revision = 1,
.family = NFPROTO_UNSPEC,
.checkentry = connmark_mt_check,
.match = connmark_mt,
.matchsize = sizeof(struct xt_connmark_mtinfo1),
.destroy = connmark_mt_destroy,
.me = THIS_MODULE,
};
static int __init connmark_mt_init(void)
{
int ret;
ret = xt_register_targets(connmark_tg_reg,
ARRAY_SIZE(connmark_tg_reg));
if (ret < 0)
return ret;
ret = xt_register_match(&connmark_mt_reg);
if (ret < 0) {
xt_unregister_targets(connmark_tg_reg,
ARRAY_SIZE(connmark_tg_reg));
return ret;
}
return 0;
}
static void __exit connmark_mt_exit(void)
{
xt_unregister_match(&connmark_mt_reg);
xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg));
}
module_init(connmark_mt_init);
module_exit(connmark_mt_exit);
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