[linux-2.6-block.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, see <http://www.gnu.org/licenses/>.
 */

#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>

#define MODULE_VERS "0.6"

MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>");
MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match");
MODULE_LICENSE("GPL");

#define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return false; }

static bool
ebt_vlan_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct ebt_vlan_info *info = par->matchinfo;

	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;

	if (vlan_tx_tag_present(skb)) {
		TCI = vlan_tx_tag_get(skb);
		encap = skb->protocol;
	} else {
		const struct vlan_hdr *fp;
		struct vlan_hdr _frame;

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

		TCI = ntohs(fp->h_vlan_TCI);
		encap = fp->h_vlan_encapsulated_proto;
	}

	/* 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. */
	id = TCI & VLAN_VID_MASK;
	prio = (TCI >> 13) & 0x7;

	/* 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 true;
}

static int ebt_vlan_mt_check(const struct xt_mtchk_param *par)
{
	struct ebt_vlan_info *info = par->matchinfo;
	const struct ebt_entry *e = par->entryinfo;

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

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

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

	/* 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_N_VID 4096. */
	if (GET_BITMASK(EBT_VLAN_ID)) {
		if (!!info->id) { /* if id!=0 => check vid range */
			if (info->id > VLAN_N_VID) {
				pr_debug("id %d is out of range (1-4096)\n",
					 info->id);
				return -EINVAL;
			}
			/* 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) {
			pr_debug("prio %d is out of range (0-7)\n",
				 info->prio);
			return -EINVAL;
		}
	}
	/* 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) {
			pr_debug("encap frame length %d is less than "
				 "minimal\n", ntohs(info->encap));
			return -EINVAL;
		}
	}

	return 0;
}

static struct xt_match ebt_vlan_mt_reg __read_mostly = {
	.name		= "vlan",
	.revision	= 0,
	.family		= NFPROTO_BRIDGE,
	.match		= ebt_vlan_mt,
	.checkentry	= ebt_vlan_mt_check,
	.matchsize	= sizeof(struct ebt_vlan_info),
	.me		= THIS_MODULE,
};

static int __init ebt_vlan_init(void)
{
	pr_debug("ebtables 802.1Q extension module v" MODULE_VERS "\n");
	return xt_register_match(&ebt_vlan_mt_reg);
}

static void __exit ebt_vlan_fini(void)
{
	xt_unregister_match(&ebt_vlan_mt_reg);
}

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
e664eabd	17	* along with this program; if not, see <http://www.gnu.org/licenses/>.
1da177e4 LT	18	*/
	19
	20	#include <linux/if_ether.h>
	21	#include <linux/if_vlan.h>
	22	#include <linux/module.h>
	23	#include <linux/moduleparam.h>
18219d3f	24	#include <linux/netfilter/x_tables.h>
1da177e4 LT	25	#include <linux/netfilter_bridge/ebtables.h>
	26	#include <linux/netfilter_bridge/ebt_vlan.h>
	27
1da177e4 LT	28	#define MODULE_VERS "0.6"
1da177e4 LT	29
1da177e4	30	MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>");
f776c4cd	31	MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match");
1da177e4 LT	32	MODULE_LICENSE("GPL");
1da177e4 LT	33
1da177e4	34	#define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
8cc784ee	35	#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return false; }
1da177e4	36
8cc784ee	37	static bool
62fc8051	38	ebt_vlan_mt(const struct sk_buff skb, struct xt_action_param par)
1da177e4	39	{
f7108a20	40	const struct ebt_vlan_info *info = par->matchinfo;
1da177e4 LT	41
	42	unsigned short TCI; /* Whole TCI, given from parsed frame */
	43	unsigned short id; /* VLAN ID, given from frame TCI */
	44	unsigned char prio; /* user_priority, given from frame TCI */
	45	/* VLAN encapsulated Type/Length field, given from orig frame */
47c183fa	46	__be16 encap;
1da177e4	47
13937911 JG	48	if (vlan_tx_tag_present(skb)) {
	49	TCI = vlan_tx_tag_get(skb);
	50	encap = skb->protocol;
	51	} else {
	52	const struct vlan_hdr *fp;
	53	struct vlan_hdr _frame;
	54
	55	fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame);
	56	if (fp == NULL)
	57	return false;
	58
	59	TCI = ntohs(fp->h_vlan_TCI);
	60	encap = fp->h_vlan_encapsulated_proto;
	61	}
1da177e4 LT	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. */
1da177e4 LT	70	id = TCI & VLAN_VID_MASK;
1da177e4 LT	71	prio = (TCI >> 13) & 0x7;
1da177e4 LT	72
	73	/* Checking VLAN Identifier (VID) */
	74	if (GET_BITMASK(EBT_VLAN_ID))
	75	EXIT_ON_MISMATCH(id, EBT_VLAN_ID);
	76
	77	/* Checking user_priority */
	78	if (GET_BITMASK(EBT_VLAN_PRIO))
	79	EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO);
	80
	81	/* Checking Encapsulated Proto (Length/Type) field */
	82	if (GET_BITMASK(EBT_VLAN_ENCAP))
	83	EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP);
	84
8cc784ee	85	return true;
1da177e4 LT	86	}
1da177e4 LT	87
b0f38452	88	static int ebt_vlan_mt_check(const struct xt_mtchk_param *par)
1da177e4	89	{
9b4fce7a JE	90	struct ebt_vlan_info *info = par->matchinfo;
9b4fce7a JE	91	const struct ebt_entry *e = par->entryinfo;
1da177e4	92
1da177e4 LT	93	/* Is it 802.1Q frame checked? */
1da177e4 LT	94	if (e->ethproto != htons(ETH_P_8021Q)) {
ff67e4e4 JE	95	pr_debug("passed entry proto %2.4X is not 802.1Q (8100)\n",
ff67e4e4 JE	96	ntohs(e->ethproto));
bd414ee6	97	return -EINVAL;
1da177e4 LT	98	}
	99
	100	/* Check for bitmask range
	101	* True if even one bit is out of mask */
	102	if (info->bitmask & ~EBT_VLAN_MASK) {
ff67e4e4 JE	103	pr_debug("bitmask %2X is out of mask (%2X)\n",
ff67e4e4 JE	104	info->bitmask, EBT_VLAN_MASK);
bd414ee6	105	return -EINVAL;
1da177e4 LT	106	}
	107
	108	/* Check for inversion flags range */
	109	if (info->invflags & ~EBT_VLAN_MASK) {
ff67e4e4 JE	110	pr_debug("inversion flags %2X is out of mask (%2X)\n",
ff67e4e4 JE	111	info->invflags, EBT_VLAN_MASK);
bd414ee6	112	return -EINVAL;
1da177e4 LT	113	}
	114
	115	/* Reserved VLAN ID (VID) values
	116	* -----------------------------
9d6f229f	117	* 0 - The null VLAN ID.
1da177e4	118	* 1 - The default Port VID (PVID)
9d6f229f	119	* 0x0FFF - Reserved for implementation use.
b738127d	120	* if_vlan.h: VLAN_N_VID 4096. */
1da177e4 LT	121	if (GET_BITMASK(EBT_VLAN_ID)) {
1da177e4 LT	122	if (!!info->id) { /* if id!=0 => check vid range */
b738127d	123	if (info->id > VLAN_N_VID) {
ff67e4e4 JE	124	pr_debug("id %d is out of range (1-4096)\n",
ff67e4e4 JE	125	info->id);
bd414ee6	126	return -EINVAL;
1da177e4 LT	127	}
1da177e4 LT	128	/* Note: This is valid VLAN-tagged frame point.
9d6f229f	129	* Any value of user_priority are acceptable,
1da177e4 LT	130	* but should be ignored according to 802.1Q Std.
	131	* So we just drop the prio flag. */
	132	info->bitmask &= ~EBT_VLAN_PRIO;
	133	}
	134	/* Else, id=0 (null VLAN ID) => user_priority range (any?) */
	135	}
	136
	137	if (GET_BITMASK(EBT_VLAN_PRIO)) {
	138	if ((unsigned char) info->prio > 7) {
ff67e4e4 JE	139	pr_debug("prio %d is out of range (0-7)\n",
ff67e4e4 JE	140	info->prio);
bd414ee6	141	return -EINVAL;
1da177e4 LT	142	}
	143	}
	144	/* Check for encapsulated proto range - it is possible to be
	145	* any value for u_short range.
	146	* if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS */
	147	if (GET_BITMASK(EBT_VLAN_ENCAP)) {
	148	if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) {
ff67e4e4 JE	149	pr_debug("encap frame length %d is less than "
ff67e4e4 JE	150	"minimal\n", ntohs(info->encap));
bd414ee6	151	return -EINVAL;
1da177e4 LT	152	}
	153	}
	154
bd414ee6	155	return 0;
1da177e4 LT	156	}
1da177e4 LT	157
043ef46c JE	158	static struct xt_match ebt_vlan_mt_reg __read_mostly = {
043ef46c JE	159	.name = "vlan",
001a18d3 JE	160	.revision = 0,
001a18d3 JE	161	.family = NFPROTO_BRIDGE,
2d06d4a5 JE	162	.match = ebt_vlan_mt,
2d06d4a5 JE	163	.checkentry = ebt_vlan_mt_check,
fc0e3df4	164	.matchsize = sizeof(struct ebt_vlan_info),
1da177e4 LT	165	.me = THIS_MODULE,
	166	};
	167
65b4b4e8	168	static int __init ebt_vlan_init(void)
1da177e4	169	{
ff67e4e4	170	pr_debug("ebtables 802.1Q extension module v" MODULE_VERS "\n");
043ef46c	171	return xt_register_match(&ebt_vlan_mt_reg);
1da177e4 LT	172	}
1da177e4 LT	173
65b4b4e8	174	static void __exit ebt_vlan_fini(void)
1da177e4	175	{
043ef46c	176	xt_unregister_match(&ebt_vlan_mt_reg);
1da177e4 LT	177	}
1da177e4 LT	178
65b4b4e8 AM	179	module_init(ebt_vlan_init);
65b4b4e8 AM	180	module_exit(ebt_vlan_fini);