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/*
* xt_iface - kernel module to match interface state flags
*
* Original author: Gáspár Lajos <gaspar.lajos@glsys.eu>
*/
#include <linux/if.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/version.h>
#include <linux/netfilter/x_tables.h>
#include "xt_iface.h"
#include "compat_xtables.h"
struct xt_iface_flag_pairs {
uint16_t iface_flag;
uint32_t iff_flag;
};
MODULE_AUTHOR("Gáspár Lajos <gaspar.lajos@glsys.eu>");
MODULE_DESCRIPTION("Xtables: iface match module");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_iface");
MODULE_ALIAS("ip6t_iface");
//MODULE_ALIAS("arpt_iface");
static const struct xt_iface_flag_pairs xt_iface_lookup[] =
{
{.iface_flag = XT_IFACE_UP, .iff_flag = IFF_UP},
{.iface_flag = XT_IFACE_BROADCAST, .iff_flag = IFF_BROADCAST},
{.iface_flag = XT_IFACE_LOOPBACK, .iff_flag = IFF_LOOPBACK},
{.iface_flag = XT_IFACE_POINTOPOINT, .iff_flag = IFF_POINTOPOINT},
{.iface_flag = XT_IFACE_RUNNING, .iff_flag = IFF_RUNNING},
{.iface_flag = XT_IFACE_NOARP, .iff_flag = IFF_NOARP},
{.iface_flag = XT_IFACE_PROMISC, .iff_flag = IFF_PROMISC},
{.iface_flag = XT_IFACE_MULTICAST, .iff_flag = IFF_MULTICAST},
{.iface_flag = XT_IFACE_DYNAMIC, .iff_flag = IFF_DYNAMIC},
{.iface_flag = XT_IFACE_LOWER_UP, .iff_flag = IFF_LOWER_UP},
{.iface_flag = XT_IFACE_DORMANT, .iff_flag = IFF_DORMANT},
};
static const struct net_device *iface_get(const struct xt_iface_mtinfo *info,
const struct xt_action_param *par, struct net_device **put)
{
if (info->flags & XT_IFACE_DEV_IN)
return par->state->in;
else if (info->flags & XT_IFACE_DEV_OUT)
return par->state->out;
return *put = dev_get_by_name(&init_net, info->ifname);
}
static bool iface_flagtest(unsigned int devflags, unsigned int flags,
unsigned int invflags)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(xt_iface_lookup); ++i)
if ((flags & xt_iface_lookup[i].iface_flag) &&
!!(devflags & xt_iface_lookup[i].iff_flag) ^
!(invflags & xt_iface_lookup[i].iface_flag))
return false;
return true;
}
static bool xt_iface_mt(const struct sk_buff *skb,
struct xt_action_param *par)
{
const struct xt_iface_mtinfo *info = par->matchinfo;
struct net_device *put = NULL;
const struct net_device *dev = iface_get(info, par, &put);
bool retval;
if (dev == NULL)
return false;
retval = iface_flagtest(dev->flags, info->flags, info->invflags);
if (put != NULL)
dev_put(put);
return retval;
}
static struct xt_match xt_iface_mt_reg[] __read_mostly = {
{
.name = "iface",
.revision = 0,
.family = NFPROTO_IPV4,
.matchsize = sizeof(struct xt_iface_mtinfo),
.match = xt_iface_mt,
.me = THIS_MODULE,
},
{
.name = "iface",
.revision = 0,
.family = NFPROTO_IPV6,
.matchsize = sizeof(struct xt_iface_mtinfo),
.match = xt_iface_mt,
.me = THIS_MODULE,
},
};
static int __init xt_iface_match_init(void)
{
return xt_register_matches(xt_iface_mt_reg,
ARRAY_SIZE(xt_iface_mt_reg));
}
static void __exit xt_iface_match_exit(void)
{
xt_unregister_matches(xt_iface_mt_reg, ARRAY_SIZE(xt_iface_mt_reg));
}
module_init(xt_iface_match_init);
module_exit(xt_iface_match_exit);
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