[net-next-2.6.git] / net / bridge / netfilter / ebt_vlan.c

/*
 * Description: EBTables 802.1Q match extension kernelspace module.
 * Authors: Nick Fedchik <nick@fedchik.org.ua>
 *          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 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/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_vlan.h>

static int debug;
#define MODULE_VERS "0.6"

module_param(debug, int, 0);
MODULE_PARM_DESC(debug, "debug=1 is turn on debug messages");
MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>");
MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match");
MODULE_LICENSE("GPL");


#define DEBUG_MSG(args...) if (debug) printk (KERN_DEBUG "ebt_vlan: " args)
#define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return EBT_NOMATCH;}

static int
ebt_filter_vlan(const struct sk_buff *skb,
		const struct net_device *in,
		const struct net_device *out,
		const void *data, unsigned int datalen)
{
	const struct ebt_vlan_info *info = data;
	const struct vlan_hdr *fp;
	struct vlan_hdr _frame;

	unsigned short TCI;	/* Whole TCI, given from parsed frame */
	unsigned short id;	/* VLAN ID, given from frame TCI */
	unsigned char prio;	/* user_priority, given from frame TCI */
	/* VLAN encapsulated Type/Length field, given from orig frame */
	__be16 encap;

	fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame);
	if (fp == NULL)
		return EBT_NOMATCH;

	/* Tag Control Information (TCI) consists of the following elements:
	 * - User_priority. The user_priority field is three bits in length,
	 * interpreted as a binary number.
	 * - Canonical Format Indicator (CFI). The Canonical Format Indicator
	 * (CFI) is a single bit flag value. Currently ignored.
	 * - VLAN Identifier (VID). The VID is encoded as
	 * an unsigned binary number. */
	TCI = ntohs(fp->h_vlan_TCI);
	id = TCI & VLAN_VID_MASK;
	prio = (TCI >> 13) & 0x7;
	encap = fp->h_vlan_encapsulated_proto;

	/* Checking VLAN Identifier (VID) */
	if (GET_BITMASK(EBT_VLAN_ID))
		EXIT_ON_MISMATCH(id, EBT_VLAN_ID);

	/* Checking user_priority */
	if (GET_BITMASK(EBT_VLAN_PRIO))
		EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO);

	/* Checking Encapsulated Proto (Length/Type) field */
	if (GET_BITMASK(EBT_VLAN_ENCAP))
		EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP);

	return EBT_MATCH;
}

static bool
ebt_check_vlan(const char *tablename,
	       unsigned int hooknr,
	       const struct ebt_entry *e, void *data, unsigned int datalen)
{
	struct ebt_vlan_info *info = data;

	/* Is it 802.1Q frame checked? */
	if (e->ethproto != htons(ETH_P_8021Q)) {
		DEBUG_MSG
		    ("passed entry proto %2.4X is not 802.1Q (8100)\n",
		     (unsigned short) ntohs(e->ethproto));
		return false;
	}

	/* Check for bitmask range
	 * True if even one bit is out of mask */
	if (info->bitmask & ~EBT_VLAN_MASK) {
		DEBUG_MSG("bitmask %2X is out of mask (%2X)\n",
			  info->bitmask, EBT_VLAN_MASK);
		return false;
	}

	/* Check for inversion flags range */
	if (info->invflags & ~EBT_VLAN_MASK) {
		DEBUG_MSG("inversion flags %2X is out of mask (%2X)\n",
			  info->invflags, EBT_VLAN_MASK);
		return false;
	}

	/* Reserved VLAN ID (VID) values
	 * -----------------------------
	 * 0 - The null VLAN ID.
	 * 1 - The default Port VID (PVID)
	 * 0x0FFF - Reserved for implementation use.
	 * if_vlan.h: VLAN_GROUP_ARRAY_LEN 4096. */
	if (GET_BITMASK(EBT_VLAN_ID)) {
		if (!!info->id) { /* if id!=0 => check vid range */
			if (info->id > VLAN_GROUP_ARRAY_LEN) {
				DEBUG_MSG
				    ("id %d is out of range (1-4096)\n",
				     info->id);
				return false;
			}
			/* Note: This is valid VLAN-tagged frame point.
			 * Any value of user_priority are acceptable,
			 * but should be ignored according to 802.1Q Std.
			 * So we just drop the prio flag. */
			info->bitmask &= ~EBT_VLAN_PRIO;
		}
		/* Else, id=0 (null VLAN ID)  => user_priority range (any?) */
	}

	if (GET_BITMASK(EBT_VLAN_PRIO)) {
		if ((unsigned char) info->prio > 7) {
			DEBUG_MSG("prio %d is out of range (0-7)\n",
			     info->prio);
			return false;
		}
	}
	/* Check for encapsulated proto range - it is possible to be
	 * any value for u_short range.
	 * if_ether.h:  ETH_ZLEN        60   -  Min. octets in frame sans FCS */
	if (GET_BITMASK(EBT_VLAN_ENCAP)) {
		if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) {
			DEBUG_MSG
			    ("encap frame length %d is less than minimal\n",
			     ntohs(info->encap));
			return false;
		}
	}

	return true;
}

static struct ebt_match filter_vlan __read_mostly = {
	.name		= EBT_VLAN_MATCH,
	.match		= ebt_filter_vlan,
	.check		= ebt_check_vlan,
	.matchsize	= XT_ALIGN(sizeof(struct ebt_vlan_info)),
	.me		= THIS_MODULE,
};

static int __init ebt_vlan_init(void)
{
	DEBUG_MSG("ebtables 802.1Q extension module v"
		  MODULE_VERS "\n");
	DEBUG_MSG("module debug=%d\n", !!debug);
	return ebt_register_match(&filter_vlan);
}

static void __exit ebt_vlan_fini(void)
{
	ebt_unregister_match(&filter_vlan);
}

module_init(ebt_vlan_init);
module_exit(ebt_vlan_fini);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Description: EBTables 802.1Q match extension kernelspace module.
	3	* Authors: Nick Fedchik <nick@fedchik.org.ua>
	4	* Bart De Schuymer <bdschuym@pandora.be>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*/
	20
	21	#include <linux/if_ether.h>
	22	#include <linux/if_vlan.h>
	23	#include <linux/module.h>
	24	#include <linux/moduleparam.h>
18219d3f	25	#include <linux/netfilter/x_tables.h>
1da177e4 LT	26	#include <linux/netfilter_bridge/ebtables.h>
	27	#include <linux/netfilter_bridge/ebt_vlan.h>
	28
	29	static int debug;
	30	#define MODULE_VERS "0.6"
	31
	32	module_param(debug, int, 0);
	33	MODULE_PARM_DESC(debug, "debug=1 is turn on debug messages");
	34	MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>");
f776c4cd	35	MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match");
1da177e4 LT	36	MODULE_LICENSE("GPL");
	37
	38
	39	#define DEBUG_MSG(args...) if (debug) printk (KERN_DEBUG "ebt_vlan: " args)
1da177e4	40	#define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
1da177e4 LT	41	#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return EBT_NOMATCH;}
	42
	43	static int
	44	ebt_filter_vlan(const struct sk_buff *skb,
	45	const struct net_device *in,
	46	const struct net_device *out,
	47	const void *data, unsigned int datalen)
	48	{
abfdf1c4 JE	49	const struct ebt_vlan_info *info = data;
	50	const struct vlan_hdr *fp;
	51	struct vlan_hdr _frame;
1da177e4 LT	52
	53	unsigned short TCI; /* Whole TCI, given from parsed frame */
	54	unsigned short id; /* VLAN ID, given from frame TCI */
	55	unsigned char prio; /* user_priority, given from frame TCI */
	56	/* VLAN encapsulated Type/Length field, given from orig frame */
47c183fa	57	__be16 encap;
1da177e4 LT	58
	59	fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame);
	60	if (fp == NULL)
	61	return EBT_NOMATCH;
	62
	63	/* Tag Control Information (TCI) consists of the following elements:
	64	* - User_priority. The user_priority field is three bits in length,
	65	* interpreted as a binary number.
	66	* - Canonical Format Indicator (CFI). The Canonical Format Indicator
	67	* (CFI) is a single bit flag value. Currently ignored.
	68	* - VLAN Identifier (VID). The VID is encoded as
	69	* an unsigned binary number. */
	70	TCI = ntohs(fp->h_vlan_TCI);
	71	id = TCI & VLAN_VID_MASK;
	72	prio = (TCI >> 13) & 0x7;
	73	encap = fp->h_vlan_encapsulated_proto;
	74
	75	/* Checking VLAN Identifier (VID) */
	76	if (GET_BITMASK(EBT_VLAN_ID))
	77	EXIT_ON_MISMATCH(id, EBT_VLAN_ID);
	78
	79	/* Checking user_priority */
	80	if (GET_BITMASK(EBT_VLAN_PRIO))
	81	EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO);
	82
	83	/* Checking Encapsulated Proto (Length/Type) field */
	84	if (GET_BITMASK(EBT_VLAN_ENCAP))
	85	EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP);
	86
	87	return EBT_MATCH;
	88	}
	89
19eda879	90	static bool
1da177e4 LT	91	ebt_check_vlan(const char *tablename,
	92	unsigned int hooknr,
	93	const struct ebt_entry e, void data, unsigned int datalen)
	94	{
abfdf1c4	95	struct ebt_vlan_info *info = data;
1da177e4	96
1da177e4 LT	97	/* Is it 802.1Q frame checked? */
	98	if (e->ethproto != htons(ETH_P_8021Q)) {
	99	DEBUG_MSG
	100	("passed entry proto %2.4X is not 802.1Q (8100)\n",
	101	(unsigned short) ntohs(e->ethproto));
19eda879	102	return false;
1da177e4 LT	103	}
	104
	105	/* Check for bitmask range
	106	* True if even one bit is out of mask */
	107	if (info->bitmask & ~EBT_VLAN_MASK) {
	108	DEBUG_MSG("bitmask %2X is out of mask (%2X)\n",
	109	info->bitmask, EBT_VLAN_MASK);
19eda879	110	return false;
1da177e4 LT	111	}
	112
	113	/* Check for inversion flags range */
	114	if (info->invflags & ~EBT_VLAN_MASK) {
	115	DEBUG_MSG("inversion flags %2X is out of mask (%2X)\n",
	116	info->invflags, EBT_VLAN_MASK);
19eda879	117	return false;
1da177e4 LT	118	}
	119
	120	/* Reserved VLAN ID (VID) values
	121	* -----------------------------
9d6f229f	122	* 0 - The null VLAN ID.
1da177e4	123	* 1 - The default Port VID (PVID)
9d6f229f	124	* 0x0FFF - Reserved for implementation use.
1da177e4 LT	125	* if_vlan.h: VLAN_GROUP_ARRAY_LEN 4096. */
	126	if (GET_BITMASK(EBT_VLAN_ID)) {
	127	if (!!info->id) { /* if id!=0 => check vid range */
	128	if (info->id > VLAN_GROUP_ARRAY_LEN) {
	129	DEBUG_MSG
	130	("id %d is out of range (1-4096)\n",
	131	info->id);
19eda879	132	return false;
1da177e4 LT	133	}
1da177e4 LT	134	/* Note: This is valid VLAN-tagged frame point.
9d6f229f	135	* Any value of user_priority are acceptable,
1da177e4 LT	136	* but should be ignored according to 802.1Q Std.
	137	* So we just drop the prio flag. */
	138	info->bitmask &= ~EBT_VLAN_PRIO;
	139	}
	140	/* Else, id=0 (null VLAN ID) => user_priority range (any?) */
	141	}
	142
	143	if (GET_BITMASK(EBT_VLAN_PRIO)) {
	144	if ((unsigned char) info->prio > 7) {
	145	DEBUG_MSG("prio %d is out of range (0-7)\n",
	146	info->prio);
19eda879	147	return false;
1da177e4 LT	148	}
	149	}
	150	/* Check for encapsulated proto range - it is possible to be
	151	* any value for u_short range.
	152	* if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS */
	153	if (GET_BITMASK(EBT_VLAN_ENCAP)) {
	154	if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) {
	155	DEBUG_MSG
	156	("encap frame length %d is less than minimal\n",
	157	ntohs(info->encap));
19eda879	158	return false;
1da177e4 LT	159	}
	160	}
	161
19eda879	162	return true;
1da177e4 LT	163	}
1da177e4 LT	164
30083c95	165	static struct ebt_match filter_vlan __read_mostly = {
1da177e4 LT	166	.name = EBT_VLAN_MATCH,
	167	.match = ebt_filter_vlan,
	168	.check = ebt_check_vlan,
18219d3f	169	.matchsize = XT_ALIGN(sizeof(struct ebt_vlan_info)),
1da177e4 LT	170	.me = THIS_MODULE,
	171	};
	172
65b4b4e8	173	static int __init ebt_vlan_init(void)
1da177e4 LT	174	{
	175	DEBUG_MSG("ebtables 802.1Q extension module v"
	176	MODULE_VERS "\n");
	177	DEBUG_MSG("module debug=%d\n", !!debug);
	178	return ebt_register_match(&filter_vlan);
	179	}
	180
65b4b4e8	181	static void __exit ebt_vlan_fini(void)
1da177e4 LT	182	{
	183	ebt_unregister_match(&filter_vlan);
	184	}
	185
65b4b4e8 AM	186	module_init(ebt_vlan_init);
65b4b4e8 AM	187	module_exit(ebt_vlan_fini);