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authorfnm3 <fnm3>2002-06-25 16:49:11 +0000
committerfnm3 <fnm3>2002-06-25 16:49:11 +0000
commit12ebd551a2e43637c3f8417c62201753739386e6 (patch)
tree18501861e9c8c8e6883256ecf5c91bad8337c01c /kernel/linux/net/bridge
parentf8ea9ee8438748907c9e4e1e55f1e610e8d1d6be (diff)
Code redesign. Lot of debug messages. Checks for passed parameters.
Diffstat (limited to 'kernel/linux/net/bridge')
-rw-r--r--kernel/linux/net/bridge/netfilter/ebt_vlan.c342
1 files changed, 254 insertions, 88 deletions
diff --git a/kernel/linux/net/bridge/netfilter/ebt_vlan.c b/kernel/linux/net/bridge/netfilter/ebt_vlan.c
index b7fcb3f..68e7966 100644
--- a/kernel/linux/net/bridge/netfilter/ebt_vlan.c
+++ b/kernel/linux/net/bridge/netfilter/ebt_vlan.c
@@ -1,120 +1,284 @@
/*
- * ebt_vlan kernelspace
- *
- * Authors:
- * Bart De Schuymer <bart.de.schuymer@pandora.be>
- * Nick Fedchik <nick@fedchik.org.ua>
- *
- * June, 2002
+ * Description: EBTables 802.1Q match extension kernelspace module.
+ * Authors: Nick Fedchik <nick@fedchik.org.ua>
+ * Bart De Schuymer <bart.de.schuymer@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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#include <linux/netfilter_bridge/ebtables.h>
-#include <linux/netfilter_bridge/ebt_vlan.h>
-#include <linux/if_vlan.h>
#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
#include <linux/module.h>
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge/ebt_vlan.h>
static unsigned char debug;
+#define MODULE_VERSION "0.4 (" __DATE__ " " __TIME__ ")"
+
MODULE_PARM (debug, "0-1b");
MODULE_PARM_DESC (debug, "debug=1 is turn on debug messages");
+MODULE_AUTHOR ("Nick Fedchik <nick@fedchik.org.ua>");
+MODULE_DESCRIPTION ("802.1Q match module (ebtables extension), v"
+ MODULE_VERSION);
+MODULE_LICENSE ("GPL");
-#define MODULE_VERSION "0.2"
-static int ebt_filter_vlan (const struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- const void *data,
- unsigned int datalen,
- const struct ebt_counter *c)
+#define DEBUG_MSG(...) if (debug) printk (KERN_DEBUG __FILE__ ":" __FUNCTION__ ": " __VA_ARGS__)
+#define INV_FLAG(_inv_flag_) (infostuff->invflags & _inv_flag_) ? "!" : ""
+#define GET_BITMASK(_BIT_MASK_) infostuff->bitmask & _BIT_MASK_
+#define SET_BITMASK(_BIT_MASK_) infostuff->bitmask |= _BIT_MASK_
+#define EXIT_ON_MISMATCH(_MATCH_,_MASK_) if (!((infostuff->_MATCH_ == _MATCH_)^!!(infostuff->invflags & _MASK_))) return 1;
+
+/*
+ * Function description: ebt_filter_vlan() is main engine for
+ * checking passed 802.1Q frame according to
+ * the passed extension parameters (in the *data buffer)
+ * ebt_filter_vlan() is called after successfull check the rule params
+ * by ebt_check_vlan() function.
+ * Parameters:
+ * const struct sk_buff *skb - pointer to passed ethernet frame buffer
+ * const void *data - pointer to passed extension parameters
+ * unsigned int datalen - length of passed *data buffer
+ * const struct net_device *in -
+ * const struct net_device *out -
+ * const struct ebt_counter *c -
+ * Returned values:
+ * 0 - ok (all rule params matched)
+ * 1 - miss (rule params not acceptable to the parsed frame)
+ */
+static int
+ebt_filter_vlan (const struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ const void *data,
+ unsigned int datalen, const struct ebt_counter *c)
{
- struct ebt_vlan_info *infostuff = (struct ebt_vlan_info *) data;
- struct vlan_ethhdr *vlanethhdr =
- (struct vlan_ethhdr *) skb->mac.raw;
- unsigned short v_id;
- unsigned short v_prio;
- unsigned short v_TCI;
+ struct ebt_vlan_info *infostuff = (struct ebt_vlan_info *) data; /* userspace data */
+ struct vlan_ethhdr *frame = (struct vlan_ethhdr *) skb->mac.raw; /* Passed tagged frame */
- /*
- * Calculate 802.1Q VLAN ID and user_priority from
- * Tag Control Information (TCI) field.
- * Reserved one bit (13) for CFI (Canonical Format Indicator)
- */
- v_TCI = ntohs (vlanethhdr->h_vlan_TCI);
- v_id = v_TCI & 0xFFF;
- v_prio = v_TCI >> 13;
+ 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 */
+ unsigned short encap; /* VLAN encapsulated Type/Length field, given from orig frame */
/*
- * Checking VLANs
+ * Tag Control Information (TCI) consists of the following elements:
+ * - User_priority. This field allows the tagged frame to carry user_priority
+ * information across Bridged LANs in which individual LAN segments may be unable to signal
+ * priority information (e.g., 802.3/Ethernet segments).
+ * The user_priority field is three bits in length,
+ * interpreted as a binary number. The user_priority is therefore
+ * capable of representing eight priority levels, 0 through 7.
+ * The use and interpretation of this field is defined in ISO/IEC 15802-3.
+ * - Canonical Format Indicator (CFI). This field is used,
+ * in 802.3/Ethernet, to signal the presence or absence
+ * of a RIF field, and, in combination with the Non-canonical Format Indicator (NCFI) carried
+ * in the RIF, to signal the bit order of address information carried in the encapsulated
+ * frame. The Canonical Format Indicator (CFI) is a single bit flag value.
+ * - VLAN Identifier (VID). This field uniquely identifies the VLAN to
+ * which the frame belongs. The twelve-bit VLAN Identifier (VID) field
+ * uniquely identify the VLAN to which the frame belongs.
+ * The VID is encoded as an unsigned binary number.
*/
- if (infostuff->bitmask & EBT_VLAN_ID) { /* Is VLAN ID parsed? */
- if (!((infostuff->id == v_id)
- ^ !!(infostuff->invflags & EBT_VLAN_ID)))
- return 1;
- if (debug)
- printk (KERN_DEBUG
- "ebt_vlan: matched ID=%s%d (mask=%X)\n",
- (infostuff->
- invflags & EBT_VLAN_ID) ? "!" : "",
- infostuff->id, infostuff->bitmask);
- }
+ TCI = ntohs (frame->h_vlan_TCI);
+ id = TCI & 0xFFF;
+ prio = TCI >> 13;
+ encap = frame->h_vlan_encapsulated_proto;
+
/*
- * Checking User Priority
+ * First step is to check is null VLAN ID present
+ * in the parsed frame
*/
- if (infostuff->bitmask & EBT_VLAN_PRIO) { /* Is VLAN Prio parsed? */
- if (!((infostuff->prio == v_prio)
- ^ !!(infostuff->invflags & EBT_VLAN_PRIO)))
- return 1; /* missed */
- if (debug)
- printk (KERN_DEBUG
- "ebt_vlan: matched Prio=%s%d (mask=%X)\n",
- (infostuff->
- invflags & EBT_VLAN_PRIO) ? "!" : "",
- infostuff->prio, infostuff->bitmask);
+ if (!(id)) {
+ /*
+ * Checking VLAN Identifier (VID)
+ */
+ if (GET_BITMASK (EBT_VLAN_ID)) { /* Is VLAN ID parsed? */
+ EXIT_ON_MISMATCH (id, EBT_VLAN_ID);
+ DEBUG_MSG
+ ("matched rule id=%s%d for frame id=%d\n",
+ INV_FLAG (EBT_VLAN_ID), infostuff->id, id);
+ }
+ } else {
+ /*
+ * Checking user_priority
+ */
+ if (GET_BITMASK (EBT_VLAN_PRIO)) { /* Is VLAN user_priority parsed? */
+ EXIT_ON_MISMATCH (prio, EBT_VLAN_PRIO);
+ DEBUG_MSG
+ ("matched rule prio=%s%d for frame prio=%d\n",
+ INV_FLAG (EBT_VLAN_PRIO), infostuff->prio,
+ prio);
+ }
}
/*
- * Checking for Encapsulated proto
+ * Checking Encapsulated Proto (Length/Type) field
*/
- if (infostuff->bitmask & EBT_VLAN_ENCAP) { /* Is VLAN Encap parsed? */
- if (!
- ((infostuff->encap ==
- vlanethhdr->h_vlan_encapsulated_proto)
- ^ !!(infostuff->invflags & EBT_VLAN_ENCAP)))
- return 1; /* missed */
- if (debug)
- printk (KERN_DEBUG
- "ebt_vlan: matched encap=%s%2.4X (mask=%X)\n",
- (infostuff->
- invflags & EBT_VLAN_ENCAP) ? "!" : "",
- ntohs (infostuff->encap),
- infostuff->bitmask);
+ if (GET_BITMASK (EBT_VLAN_ENCAP)) { /* Is VLAN Encap parsed? */
+ EXIT_ON_MISMATCH (encap, EBT_VLAN_ENCAP);
+ DEBUG_MSG ("matched encap=%s%2.4X for frame encap=%2.4X\n",
+ INV_FLAG (EBT_VLAN_ENCAP),
+ ntohs (infostuff->encap), ntohs (encap));
}
-
/*
- * rule matched
+ * All possible extension parameters was parsed.
+ * If rule never returned by missmatch, then all ok.
*/
return 0;
}
/*
- * ebt_vlan_check() is called when userspace delivers the table to the kernel,
- * * it is called to check that userspace doesn't give a bad table.
+ * Function description: ebt_vlan_check() is called when userspace
+ * delivers the table to the kernel,
+ * and to check that userspace doesn't give a bad table.
+ * Parameters:
+ * const char *tablename - table name string
+ * unsigned int hooknr - hook number
+ * const struct ebt_entry *e - ebtables entry basic set
+ * const void *data - pointer to passed extension parameters
+ * unsigned int datalen - length of passed *data buffer
+ * Returned values:
+ * 0 - ok (all delivered rule params are correct)
+ * 1 - miss (rule params is out of range, invalid, incompatible, etc.)
*/
-static int ebt_vlan_check (const char *tablename, unsigned int hookmask,
- const struct ebt_entry *e, void *data,
- unsigned int datalen)
+static int
+ebt_check_vlan (const char *tablename,
+ unsigned int hooknr,
+ const struct ebt_entry *e, void *data,
+ unsigned int datalen)
{
struct ebt_vlan_info *infostuff = (struct ebt_vlan_info *) data;
- if (datalen != sizeof (struct ebt_vlan_info))
+ /*
+ * Parameters buffer overflow check
+ */
+ if (datalen != sizeof (struct ebt_vlan_info)) {
+ DEBUG_MSG
+ ("params size %d is not eq to ebt_vlan_info (%d)\n",
+ datalen, sizeof (struct ebt_vlan_info));
return -EINVAL;
+ }
- if (e->ethproto != __constant_htons (ETH_P_8021Q))
+ /*
+ * Is it 802.1Q frame checked?
+ */
+ if (e->ethproto != __constant_htons (ETH_P_8021Q)) {
+ DEBUG_MSG ("passed frame %2.4X is not 802.1Q (8100)\n",
+ (unsigned short) ntohs (e->ethproto));
return -EINVAL;
+ }
+ /*
+ * Check for bitmask range
+ * True if even one bit is out of mask
+ */
if (infostuff->bitmask & ~EBT_VLAN_MASK) {
+ DEBUG_MSG ("bitmask %2X is out of mask (%2X)\n",
+ infostuff->bitmask, EBT_VLAN_MASK);
+ return -EINVAL;
+ }
+
+ /*
+ * Check for inversion flags range
+ */
+ if (infostuff->invflags & ~EBT_VLAN_MASK) {
+ DEBUG_MSG ("inversion flags %2X is out of mask (%2X)\n",
+ infostuff->invflags, EBT_VLAN_MASK);
return -EINVAL;
}
+ /*
+ * Reserved VLAN ID (VID) values
+ * -----------------------------
+ * 0 - The null VLAN ID. Indicates that the tag header contains only user_priority information;
+ * no VLAN identifier is present in the frame. This VID value shall not be
+ * configured as a PVID, configured in any Filtering Database entry, or used in any
+ * Management operation.
+ *
+ * 1 - The default Port VID (PVID) value used for classifying frames on ingress through a Bridge
+ * Port. The PVID value can be changed by management on a per-Port basis.
+ *
+ * 0x0FFF - Reserved for implementation use. This VID value shall not be configured as a
+ * PVID or transmitted in a tag header.
+ *
+ * The remaining values of VID are available for general use as VLAN identifiers.
+ * A Bridge may implement the ability to support less than the full range of VID values;
+ * i.e., for a given implementation,
+ * an upper limit, N, is defined for the VID values supported, where N is less than or equal to 4094.
+ * All implementations shall support the use of all VID values in the range 0 through their defined maximum
+ * VID, N.
+ *
+ * For Linux, N = 4094.
+ */
+ if (GET_BITMASK (EBT_VLAN_ID)) { /* when vlan-id param was spec-ed */
+ if (!!infostuff->id) { /* if id!=0 => check vid range */
+ if (infostuff->id > 4094) { /* check if id > than (0x0FFE) */
+ DEBUG_MSG
+ ("vlan id %d is out of range (1-4094)\n",
+ infostuff->id);
+ return -EINVAL;
+ }
+ /*
+ * Note: This is valid VLAN-tagged frame point.
+ * Any value of user_priority are acceptable, but could be ignored
+ * according to 802.1Q Std.
+ */
+ } else {
+ /*
+ * if id=0 (null VLAN ID) => Check for user_priority range
+ */
+ if (GET_BITMASK (EBT_VLAN_PRIO)) {
+ if ((unsigned char) infostuff->prio > 7) {
+ DEBUG_MSG
+ ("prio %d is out of range (0-7)\n",
+ infostuff->prio);
+ return -EINVAL;
+ }
+ }
+ /*
+ * Note2: This is valid priority-tagged frame point
+ * with null VID field.
+ */
+ }
+ } else { /* VLAN Id not set */
+ if (GET_BITMASK (EBT_VLAN_PRIO)) { /* But user_priority is set - abnormal! */
+ infostuff->id = 0; /* Set null VID (case for Priority-tagged frames) */
+ SET_BITMASK (EBT_VLAN_ID); /* and set id flag */
+ }
+ }
+ /*
+ * Check for encapsulated proto range - it is possible to be any value for u_short range.
+ * When relaying a tagged frame between 802.3/Ethernet MACs,
+ * a Bridge may adjust the padding field such that
+ * the minimum size of a transmitted tagged frame is 68 octets (7.2).
+ * if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS
+ */
+ if (GET_BITMASK (EBT_VLAN_ENCAP)) {
+ if ((unsigned short) ntohs (infostuff->encap) < ETH_ZLEN) {
+ DEBUG_MSG
+ ("encap packet length %d is less than minimal %d\n",
+ ntohs (infostuff->encap), ETH_ZLEN);
+ return -EINVAL;
+ }
+ }
+
+ /*
+ * Otherwise is all correct
+ */
+ DEBUG_MSG ("802.1Q tagged frame checked (%s table, %d hook)\n",
+ tablename, hooknr);
return 0;
}
@@ -122,22 +286,27 @@ static struct ebt_match filter_vlan = {
{NULL, NULL},
EBT_VLAN_MATCH,
ebt_filter_vlan,
- ebt_vlan_check,
+ ebt_check_vlan,
NULL,
THIS_MODULE
};
+/*
+ * Module initialization function.
+ * Called when module is loaded to kernelspace
+ */
static int __init init (void)
{
- printk (KERN_INFO
- "ebt_vlan: 802.1Q VLAN matching module for EBTables "
- MODULE_VERSION "\n");
- if (debug)
- printk (KERN_DEBUG
- "ebt_vlan: 802.1Q rule matching debug is on\n");
+ DEBUG_MSG ("ebtables 802.1Q extension module v"
+ MODULE_VERSION "\n");
+ DEBUG_MSG ("module debug=%d\n", !!debug);
return ebt_register_match (&filter_vlan);
}
+/*
+ * Module "finalization" function
+ * Called when download module from kernelspace
+ */
static void __exit fini (void)
{
ebt_unregister_match (&filter_vlan);
@@ -145,8 +314,5 @@ static void __exit fini (void)
module_init (init);
module_exit (fini);
+
EXPORT_NO_SYMBOLS;
-MODULE_AUTHOR ("Nick Fedchik <nick@fedchik.org.ua>");
-MODULE_DESCRIPTION ("802.1Q VLAN matching module for ebtables, v"
- MODULE_VERSION);
-MODULE_LICENSE ("GPL");