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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 |
f7108a20 | 44 | ebt_vlan_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
1da177e4 | 45 | { |
f7108a20 | 46 | const struct ebt_vlan_info *info = par->matchinfo; |
abfdf1c4 JE |
47 | const struct vlan_hdr *fp; |
48 | struct vlan_hdr _frame; | |
1da177e4 LT |
49 | |
50 | unsigned short TCI; /* Whole TCI, given from parsed frame */ | |
51 | unsigned short id; /* VLAN ID, given from frame TCI */ | |
52 | unsigned char prio; /* user_priority, given from frame TCI */ | |
53 | /* VLAN encapsulated Type/Length field, given from orig frame */ | |
47c183fa | 54 | __be16 encap; |
1da177e4 LT |
55 | |
56 | fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame); | |
57 | if (fp == NULL) | |
8cc784ee | 58 | return false; |
1da177e4 LT |
59 | |
60 | /* Tag Control Information (TCI) consists of the following elements: | |
61 | * - User_priority. The user_priority field is three bits in length, | |
62 | * interpreted as a binary number. | |
63 | * - Canonical Format Indicator (CFI). The Canonical Format Indicator | |
64 | * (CFI) is a single bit flag value. Currently ignored. | |
65 | * - VLAN Identifier (VID). The VID is encoded as | |
66 | * an unsigned binary number. */ | |
67 | TCI = ntohs(fp->h_vlan_TCI); | |
68 | id = TCI & VLAN_VID_MASK; | |
69 | prio = (TCI >> 13) & 0x7; | |
70 | encap = fp->h_vlan_encapsulated_proto; | |
71 | ||
72 | /* Checking VLAN Identifier (VID) */ | |
73 | if (GET_BITMASK(EBT_VLAN_ID)) | |
74 | EXIT_ON_MISMATCH(id, EBT_VLAN_ID); | |
75 | ||
76 | /* Checking user_priority */ | |
77 | if (GET_BITMASK(EBT_VLAN_PRIO)) | |
78 | EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO); | |
79 | ||
80 | /* Checking Encapsulated Proto (Length/Type) field */ | |
81 | if (GET_BITMASK(EBT_VLAN_ENCAP)) | |
82 | EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP); | |
83 | ||
8cc784ee | 84 | return true; |
1da177e4 LT |
85 | } |
86 | ||
19eda879 | 87 | static bool |
2d06d4a5 JE |
88 | ebt_vlan_mt_check(const char *table, const void *entry, |
89 | const struct xt_match *match, void *data, | |
90 | unsigned int hook_mask) | |
1da177e4 | 91 | { |
abfdf1c4 | 92 | struct ebt_vlan_info *info = data; |
2d06d4a5 | 93 | const struct ebt_entry *e = entry; |
1da177e4 | 94 | |
1da177e4 LT |
95 | /* Is it 802.1Q frame checked? */ |
96 | if (e->ethproto != htons(ETH_P_8021Q)) { | |
97 | DEBUG_MSG | |
98 | ("passed entry proto %2.4X is not 802.1Q (8100)\n", | |
99 | (unsigned short) ntohs(e->ethproto)); | |
19eda879 | 100 | return false; |
1da177e4 LT |
101 | } |
102 | ||
103 | /* Check for bitmask range | |
104 | * True if even one bit is out of mask */ | |
105 | if (info->bitmask & ~EBT_VLAN_MASK) { | |
106 | DEBUG_MSG("bitmask %2X is out of mask (%2X)\n", | |
107 | info->bitmask, EBT_VLAN_MASK); | |
19eda879 | 108 | return false; |
1da177e4 LT |
109 | } |
110 | ||
111 | /* Check for inversion flags range */ | |
112 | if (info->invflags & ~EBT_VLAN_MASK) { | |
113 | DEBUG_MSG("inversion flags %2X is out of mask (%2X)\n", | |
114 | info->invflags, EBT_VLAN_MASK); | |
19eda879 | 115 | return false; |
1da177e4 LT |
116 | } |
117 | ||
118 | /* Reserved VLAN ID (VID) values | |
119 | * ----------------------------- | |
9d6f229f | 120 | * 0 - The null VLAN ID. |
1da177e4 | 121 | * 1 - The default Port VID (PVID) |
9d6f229f | 122 | * 0x0FFF - Reserved for implementation use. |
1da177e4 LT |
123 | * if_vlan.h: VLAN_GROUP_ARRAY_LEN 4096. */ |
124 | if (GET_BITMASK(EBT_VLAN_ID)) { | |
125 | if (!!info->id) { /* if id!=0 => check vid range */ | |
126 | if (info->id > VLAN_GROUP_ARRAY_LEN) { | |
127 | DEBUG_MSG | |
128 | ("id %d is out of range (1-4096)\n", | |
129 | info->id); | |
19eda879 | 130 | return false; |
1da177e4 LT |
131 | } |
132 | /* Note: This is valid VLAN-tagged frame point. | |
9d6f229f | 133 | * Any value of user_priority are acceptable, |
1da177e4 LT |
134 | * but should be ignored according to 802.1Q Std. |
135 | * So we just drop the prio flag. */ | |
136 | info->bitmask &= ~EBT_VLAN_PRIO; | |
137 | } | |
138 | /* Else, id=0 (null VLAN ID) => user_priority range (any?) */ | |
139 | } | |
140 | ||
141 | if (GET_BITMASK(EBT_VLAN_PRIO)) { | |
142 | if ((unsigned char) info->prio > 7) { | |
143 | DEBUG_MSG("prio %d is out of range (0-7)\n", | |
144 | info->prio); | |
19eda879 | 145 | return false; |
1da177e4 LT |
146 | } |
147 | } | |
148 | /* Check for encapsulated proto range - it is possible to be | |
149 | * any value for u_short range. | |
150 | * if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS */ | |
151 | if (GET_BITMASK(EBT_VLAN_ENCAP)) { | |
152 | if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) { | |
153 | DEBUG_MSG | |
154 | ("encap frame length %d is less than minimal\n", | |
155 | ntohs(info->encap)); | |
19eda879 | 156 | return false; |
1da177e4 LT |
157 | } |
158 | } | |
159 | ||
19eda879 | 160 | return true; |
1da177e4 LT |
161 | } |
162 | ||
043ef46c JE |
163 | static struct xt_match ebt_vlan_mt_reg __read_mostly = { |
164 | .name = "vlan", | |
001a18d3 JE |
165 | .revision = 0, |
166 | .family = NFPROTO_BRIDGE, | |
2d06d4a5 JE |
167 | .match = ebt_vlan_mt, |
168 | .checkentry = ebt_vlan_mt_check, | |
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); | |
043ef46c | 178 | return xt_register_match(&ebt_vlan_mt_reg); |
1da177e4 LT |
179 | } |
180 | ||
65b4b4e8 | 181 | static void __exit ebt_vlan_fini(void) |
1da177e4 | 182 | { |
043ef46c | 183 | xt_unregister_match(&ebt_vlan_mt_reg); |
1da177e4 LT |
184 | } |
185 | ||
65b4b4e8 AM |
186 | module_init(ebt_vlan_init); |
187 | module_exit(ebt_vlan_fini); |