![YOSHIFUJI Hideaki](/assets/img/avatar_default.png)
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
196 lines
6 KiB
C
196 lines
6 KiB
C
/*
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* Description: EBTables 802.1Q match extension kernelspace module.
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* Authors: Nick Fedchik <nick@fedchik.org.ua>
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* Bart De Schuymer <bdschuym@pandora.be>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/if_ether.h>
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#include <linux/if_vlan.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_bridge/ebt_vlan.h>
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static int debug;
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#define MODULE_VERS "0.6"
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module_param(debug, int, 0);
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MODULE_PARM_DESC(debug, "debug=1 is turn on debug messages");
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MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>");
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MODULE_DESCRIPTION("802.1Q match module (ebtables extension), v"
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MODULE_VERS);
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MODULE_LICENSE("GPL");
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#define DEBUG_MSG(args...) if (debug) printk (KERN_DEBUG "ebt_vlan: " args)
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#define INV_FLAG(_inv_flag_) (info->invflags & _inv_flag_) ? "!" : ""
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#define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_
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#define SET_BITMASK(_BIT_MASK_) info->bitmask |= _BIT_MASK_
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#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return EBT_NOMATCH;}
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static int
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ebt_filter_vlan(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const void *data, unsigned int datalen)
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{
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struct ebt_vlan_info *info = (struct ebt_vlan_info *) data;
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struct vlan_hdr _frame, *fp;
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unsigned short TCI; /* Whole TCI, given from parsed frame */
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unsigned short id; /* VLAN ID, given from frame TCI */
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unsigned char prio; /* user_priority, given from frame TCI */
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/* VLAN encapsulated Type/Length field, given from orig frame */
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__be16 encap;
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fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame);
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if (fp == NULL)
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return EBT_NOMATCH;
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/* Tag Control Information (TCI) consists of the following elements:
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* - User_priority. The user_priority field is three bits in length,
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* interpreted as a binary number.
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* - Canonical Format Indicator (CFI). The Canonical Format Indicator
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* (CFI) is a single bit flag value. Currently ignored.
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* - VLAN Identifier (VID). The VID is encoded as
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* an unsigned binary number. */
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TCI = ntohs(fp->h_vlan_TCI);
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id = TCI & VLAN_VID_MASK;
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prio = (TCI >> 13) & 0x7;
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encap = fp->h_vlan_encapsulated_proto;
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/* Checking VLAN Identifier (VID) */
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if (GET_BITMASK(EBT_VLAN_ID))
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EXIT_ON_MISMATCH(id, EBT_VLAN_ID);
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/* Checking user_priority */
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if (GET_BITMASK(EBT_VLAN_PRIO))
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EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO);
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/* Checking Encapsulated Proto (Length/Type) field */
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if (GET_BITMASK(EBT_VLAN_ENCAP))
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EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP);
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return EBT_MATCH;
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}
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static int
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ebt_check_vlan(const char *tablename,
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unsigned int hooknr,
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const struct ebt_entry *e, void *data, unsigned int datalen)
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{
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struct ebt_vlan_info *info = (struct ebt_vlan_info *) data;
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/* Parameters buffer overflow check */
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if (datalen != EBT_ALIGN(sizeof(struct ebt_vlan_info))) {
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DEBUG_MSG
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("passed size %d is not eq to ebt_vlan_info (%Zd)\n",
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datalen, sizeof(struct ebt_vlan_info));
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return -EINVAL;
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}
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/* Is it 802.1Q frame checked? */
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if (e->ethproto != htons(ETH_P_8021Q)) {
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DEBUG_MSG
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("passed entry proto %2.4X is not 802.1Q (8100)\n",
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(unsigned short) ntohs(e->ethproto));
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return -EINVAL;
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}
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/* Check for bitmask range
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* True if even one bit is out of mask */
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if (info->bitmask & ~EBT_VLAN_MASK) {
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DEBUG_MSG("bitmask %2X is out of mask (%2X)\n",
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info->bitmask, EBT_VLAN_MASK);
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return -EINVAL;
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}
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/* Check for inversion flags range */
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if (info->invflags & ~EBT_VLAN_MASK) {
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DEBUG_MSG("inversion flags %2X is out of mask (%2X)\n",
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info->invflags, EBT_VLAN_MASK);
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return -EINVAL;
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}
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/* Reserved VLAN ID (VID) values
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* -----------------------------
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* 0 - The null VLAN ID.
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* 1 - The default Port VID (PVID)
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* 0x0FFF - Reserved for implementation use.
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* if_vlan.h: VLAN_GROUP_ARRAY_LEN 4096. */
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if (GET_BITMASK(EBT_VLAN_ID)) {
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if (!!info->id) { /* if id!=0 => check vid range */
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if (info->id > VLAN_GROUP_ARRAY_LEN) {
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DEBUG_MSG
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("id %d is out of range (1-4096)\n",
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info->id);
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return -EINVAL;
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}
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/* Note: This is valid VLAN-tagged frame point.
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* Any value of user_priority are acceptable,
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* but should be ignored according to 802.1Q Std.
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* So we just drop the prio flag. */
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info->bitmask &= ~EBT_VLAN_PRIO;
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}
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/* Else, id=0 (null VLAN ID) => user_priority range (any?) */
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}
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if (GET_BITMASK(EBT_VLAN_PRIO)) {
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if ((unsigned char) info->prio > 7) {
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DEBUG_MSG("prio %d is out of range (0-7)\n",
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info->prio);
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return -EINVAL;
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}
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}
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/* Check for encapsulated proto range - it is possible to be
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* any value for u_short range.
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* if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS */
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if (GET_BITMASK(EBT_VLAN_ENCAP)) {
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if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) {
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DEBUG_MSG
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("encap frame length %d is less than minimal\n",
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ntohs(info->encap));
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return -EINVAL;
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}
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}
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return 0;
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}
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static struct ebt_match filter_vlan = {
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.name = EBT_VLAN_MATCH,
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.match = ebt_filter_vlan,
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.check = ebt_check_vlan,
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.me = THIS_MODULE,
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};
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static int __init ebt_vlan_init(void)
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{
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DEBUG_MSG("ebtables 802.1Q extension module v"
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MODULE_VERS "\n");
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DEBUG_MSG("module debug=%d\n", !!debug);
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return ebt_register_match(&filter_vlan);
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}
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static void __exit ebt_vlan_fini(void)
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{
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ebt_unregister_match(&filter_vlan);
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}
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module_init(ebt_vlan_init);
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module_exit(ebt_vlan_fini);
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