/* 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_ipv4/ipt_physdev.h>#include <linux/netfilter_ipv4/ip_tables.h>#include <linux/netfilter_bridge.h>#define MATCH   1#define NOMATCH 0MODULE_LICENSE("GPL");MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");MODULE_DESCRIPTION("iptables bridge physical device match module");static intmatch(const struct sk_buff *skb,      const struct net_device *in,      const struct net_device *out,      const void *matchinfo,      int offset,      int *hotdrop){	int i;	static const char nulldevname[IFNAMSIZ];	const struct ipt_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 & IPT_PHYSDEV_OP_BRIDGED) &&		    !(info->invert & IPT_PHYSDEV_OP_BRIDGED))			return NOMATCH;		if ((info->bitmask & IPT_PHYSDEV_OP_ISIN) &&		    !(info->invert & IPT_PHYSDEV_OP_ISIN))			return NOMATCH;		if ((info->bitmask & IPT_PHYSDEV_OP_ISOUT) &&		    !(info->invert & IPT_PHYSDEV_OP_ISOUT))			return NOMATCH;		if ((info->bitmask & IPT_PHYSDEV_OP_IN) &&		    !(info->invert & IPT_PHYSDEV_OP_IN))			return NOMATCH;		if ((info->bitmask & IPT_PHYSDEV_OP_OUT) &&		    !(info->invert & IPT_PHYSDEV_OP_OUT))			return NOMATCH;		return MATCH;	}	/* This only makes sense in the FORWARD and POSTROUTING chains */	if ((info->bitmask & IPT_PHYSDEV_OP_BRIDGED) &&	    (!!(nf_bridge->mask & BRNF_BRIDGED) ^	    !(info->invert & IPT_PHYSDEV_OP_BRIDGED)))		return NOMATCH;	if ((info->bitmask & IPT_PHYSDEV_OP_ISIN &&	    (!nf_bridge->physindev ^ !!(info->invert & IPT_PHYSDEV_OP_ISIN))) ||	    (info->bitmask & IPT_PHYSDEV_OP_ISOUT &&	    (!nf_bridge->physoutdev ^ !!(info->invert & IPT_PHYSDEV_OP_ISOUT))))		return NOMATCH;	if (!(info->bitmask & IPT_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 & IPT_PHYSDEV_OP_IN))		return NOMATCH;match_outdev:	if (!(info->bitmask & IPT_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 & IPT_PHYSDEV_OP_OUT);}static intcheckentry(const char *tablename,		       const struct ipt_ip *ip,		       void *matchinfo,		       unsigned int matchsize,		       unsigned int hook_mask){	const struct ipt_physdev_info *info = matchinfo;	if (matchsize != IPT_ALIGN(sizeof(struct ipt_physdev_info)))		return 0;	if (!(info->bitmask & IPT_PHYSDEV_OP_MASK) ||	    info->bitmask & ~IPT_PHYSDEV_OP_MASK)		return 0;	return 1;}static struct ipt_match physdev_match = {	.name		= "physdev",	.match		= &match,	.checkentry	= &checkentry,	.me		= THIS_MODULE,};static int __init init(void){	return ipt_register_match(&physdev_match);}static void __exit fini(void){	ipt_unregister_match(&physdev_match);}module_init(init);module_exit(fini);