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/* Kernel module to match the bridge port in and
* out device for IP packets coming into contact with a bridge. */
/* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
*
* 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.
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter/xt_physdev.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge.h>
#define MATCH 1
#define NOMATCH 0
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
MODULE_DESCRIPTION("iptables bridge physical device match module");
MODULE_ALIAS("ipt_physdev");
MODULE_ALIAS("ip6t_physdev");
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
unsigned int protoff,
int *hotdrop)
{
int i;
static const char nulldevname[IFNAMSIZ];
const struct xt_physdev_info *info = matchinfo;
unsigned int ret;
const char *indev, *outdev;
struct nf_bridge_info *nf_bridge;
/* Not a bridged IP packet or no info available yet:
* LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
* the destination device will be a bridge. */
if (!(nf_bridge = skb->nf_bridge)) {
/* Return MATCH if the invert flags of the used options are on */
if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
!(info->invert & XT_PHYSDEV_OP_BRIDGED))
return NOMATCH;
if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
!(info->invert & XT_PHYSDEV_OP_ISIN))
return NOMATCH;
if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
!(info->invert & XT_PHYSDEV_OP_ISOUT))
return NOMATCH;
if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
!(info->invert & XT_PHYSDEV_OP_IN))
return NOMATCH;
if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
!(info->invert & XT_PHYSDEV_OP_OUT))
return NOMATCH;
return MATCH;
}
/* This only makes sense in the FORWARD and POSTROUTING chains */
if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
(!!(nf_bridge->mask & BRNF_BRIDGED) ^
!(info->invert & XT_PHYSDEV_OP_BRIDGED)))
return NOMATCH;
if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
(!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
(info->bitmask & XT_PHYSDEV_OP_ISOUT &&
(!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
return NOMATCH;
if (!(info->bitmask & XT_PHYSDEV_OP_IN))
goto match_outdev;
indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned int); i++) {
ret |= (((const unsigned int *)indev)[i]
^ ((const unsigned int *)info->physindev)[i])
& ((const unsigned int *)info->in_mask)[i];
}
if ((ret == 0) ^ !(info->invert & XT_PHYSDEV_OP_IN))
return NOMATCH;
match_outdev:
if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
return MATCH;
outdev = nf_bridge->physoutdev ?
nf_bridge->physoutdev->name : nulldevname;
for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned int); i++) {
ret |= (((const unsigned int *)outdev)[i]
^ ((const unsigned int *)info->physoutdev)[i])
& ((const unsigned int *)info->out_mask)[i];
}
return (ret != 0) ^ !(info->invert & XT_PHYSDEV_OP_OUT);
}
static int
checkentry(const char *tablename,
const void *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
const struct xt_physdev_info *info = matchinfo;
if (matchsize != XT_ALIGN(sizeof(struct xt_physdev_info)))
return 0;
if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
info->bitmask & ~XT_PHYSDEV_OP_MASK)
return 0;
return 1;
}
static struct xt_match physdev_match = {
.name = "physdev",
.match = &match,
.checkentry = &checkentry,
.me = THIS_MODULE,
};
static struct xt_match physdev6_match = {
.name = "physdev",
.match = &match,
.checkentry = &checkentry,
.me = THIS_MODULE,
};
static int __init init(void)
{
int ret;
ret = xt_register_match(AF_INET, &physdev_match);
if (ret < 0)
return ret;
ret = xt_register_match(AF_INET6, &physdev6_match);
if (ret < 0)
xt_unregister_match(AF_INET, &physdev_match);
return ret;
}
static void __exit fini(void)
{
xt_unregister_match(AF_INET, &physdev_match);
xt_unregister_match(AF_INET6, &physdev6_match);
}
module_init(init);
module_exit(fini);
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