--- /dev/null
+/*
+ * 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 (skb_vlan_tag_present(skb)) {
+ TCI = skb_vlan_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);
Code Review / kvmfornfv.git / blobdiff