]>
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_ |
8cc784ee | 41 | #define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return false; } |
1da177e4 | 42 | |
8cc784ee | 43 | static bool |
1da177e4 LT |
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) | |
8cc784ee | 61 | return false; |
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. */ | |
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 | ||
8cc784ee | 87 | return true; |
1da177e4 LT |
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 | } |
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 | } |
164 | ||
30083c95 | 165 | static struct ebt_match filter_vlan __read_mostly = { |
1da177e4 | 166 | .name = EBT_VLAN_MATCH, |
001a18d3 JE |
167 | .revision = 0, |
168 | .family = NFPROTO_BRIDGE, | |
1da177e4 LT |
169 | .match = ebt_filter_vlan, |
170 | .check = ebt_check_vlan, | |
18219d3f | 171 | .matchsize = XT_ALIGN(sizeof(struct ebt_vlan_info)), |
1da177e4 LT |
172 | .me = THIS_MODULE, |
173 | }; | |
174 | ||
65b4b4e8 | 175 | static int __init ebt_vlan_init(void) |
1da177e4 LT |
176 | { |
177 | DEBUG_MSG("ebtables 802.1Q extension module v" | |
178 | MODULE_VERS "\n"); | |
179 | DEBUG_MSG("module debug=%d\n", !!debug); | |
180 | return ebt_register_match(&filter_vlan); | |
181 | } | |
182 | ||
65b4b4e8 | 183 | static void __exit ebt_vlan_fini(void) |
1da177e4 LT |
184 | { |
185 | ebt_unregister_match(&filter_vlan); | |
186 | } | |
187 | ||
65b4b4e8 AM |
188 | module_init(ebt_vlan_init); |
189 | module_exit(ebt_vlan_fini); |