2 * Description: EBTables 802.1Q match extension kernelspace module.
3 * Authors: Nick Fedchik <nick@fedchik.org.ua>
4 * Bart De Schuymer <bdschuym@pandora.be>
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.
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.
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
21 #include <linux/if_ether.h>
22 #include <linux/if_vlan.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/netfilter/x_tables.h>
26 #include <linux/netfilter_bridge/ebtables.h>
27 #include <linux/netfilter_bridge/ebt_vlan.h>
30 #define MODULE_VERS "0.6"
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>");
35 MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match");
36 MODULE_LICENSE("GPL");
39 #define DEBUG_MSG(args...) if (debug) printk (KERN_DEBUG "ebt_vlan: " args)
40 #define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
41 #define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return false; }
44 ebt_vlan_mt(const struct sk_buff *skb, const struct net_device *in,
45 const struct net_device *out, const struct xt_match *match,
46 const void *data, int offset, unsigned int protoff, bool *hotdrop)
48 const struct ebt_vlan_info *info = data;
49 const struct vlan_hdr *fp;
50 struct vlan_hdr _frame;
52 unsigned short TCI; /* Whole TCI, given from parsed frame */
53 unsigned short id; /* VLAN ID, given from frame TCI */
54 unsigned char prio; /* user_priority, given from frame TCI */
55 /* VLAN encapsulated Type/Length field, given from orig frame */
58 fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame);
62 /* Tag Control Information (TCI) consists of the following elements:
63 * - User_priority. The user_priority field is three bits in length,
64 * interpreted as a binary number.
65 * - Canonical Format Indicator (CFI). The Canonical Format Indicator
66 * (CFI) is a single bit flag value. Currently ignored.
67 * - VLAN Identifier (VID). The VID is encoded as
68 * an unsigned binary number. */
69 TCI = ntohs(fp->h_vlan_TCI);
70 id = TCI & VLAN_VID_MASK;
71 prio = (TCI >> 13) & 0x7;
72 encap = fp->h_vlan_encapsulated_proto;
74 /* Checking VLAN Identifier (VID) */
75 if (GET_BITMASK(EBT_VLAN_ID))
76 EXIT_ON_MISMATCH(id, EBT_VLAN_ID);
78 /* Checking user_priority */
79 if (GET_BITMASK(EBT_VLAN_PRIO))
80 EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO);
82 /* Checking Encapsulated Proto (Length/Type) field */
83 if (GET_BITMASK(EBT_VLAN_ENCAP))
84 EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP);
90 ebt_vlan_mt_check(const char *table, const void *entry,
91 const struct xt_match *match, void *data,
92 unsigned int hook_mask)
94 struct ebt_vlan_info *info = data;
95 const struct ebt_entry *e = entry;
97 /* Is it 802.1Q frame checked? */
98 if (e->ethproto != htons(ETH_P_8021Q)) {
100 ("passed entry proto %2.4X is not 802.1Q (8100)\n",
101 (unsigned short) ntohs(e->ethproto));
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);
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);
120 /* Reserved VLAN ID (VID) values
121 * -----------------------------
122 * 0 - The null VLAN ID.
123 * 1 - The default Port VID (PVID)
124 * 0x0FFF - Reserved for implementation use.
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) {
130 ("id %d is out of range (1-4096)\n",
134 /* Note: This is valid VLAN-tagged frame point.
135 * Any value of user_priority are acceptable,
136 * but should be ignored according to 802.1Q Std.
137 * So we just drop the prio flag. */
138 info->bitmask &= ~EBT_VLAN_PRIO;
140 /* Else, id=0 (null VLAN ID) => user_priority range (any?) */
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",
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) {
156 ("encap frame length %d is less than minimal\n",
165 static struct xt_match ebt_vlan_mt_reg __read_mostly = {
168 .family = NFPROTO_BRIDGE,
169 .match = ebt_vlan_mt,
170 .checkentry = ebt_vlan_mt_check,
171 .matchsize = XT_ALIGN(sizeof(struct ebt_vlan_info)),
175 static int __init ebt_vlan_init(void)
177 DEBUG_MSG("ebtables 802.1Q extension module v"
179 DEBUG_MSG("module debug=%d\n", !!debug);
180 return xt_register_match(&ebt_vlan_mt_reg);
183 static void __exit ebt_vlan_fini(void)
185 xt_unregister_match(&ebt_vlan_mt_reg);
188 module_init(ebt_vlan_init);
189 module_exit(ebt_vlan_fini);