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/* packet-cwids.c
* Routines for dissecting wireless ids packets sent from a Cisco
* access point to the WLSE (or whatever)
*
* $Id$
*
* Copyright 2006 Joerg Mayer (see AUTHORS file)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* With current IOS, you can use Cisco wireless Bridges/APs as
* wireless sniffers and configure them to send the data to some
* central IDS:
* interface dot11Radio 0
* station-role scanner
* monitor frames endpoint ip address 172.22.1.1 port 8999 truncate 2312
* These frames are raw, i.e. they don't have a pcap header.
* Running wireshark at the receiving end will provide those.
*/
/* 2do:
* - Find out more about the contents of the capture header
* - Protect the address fields etc (all columns?)
* - Create subelements and put each header and packet into it
* - fuzz-test the dissector
* - Find some heuristic to detect the packet automagically and
* convert dissector into a heuristic dissector
* - Is the TRY/CATCH stuff OK?
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/etypes.h>
#include <epan/expert.h>
#include <epan/prefs.h>
static guint global_udp_port = 0;
static int proto_cwids = -1;
static int hf_cwids_version = -1;
static int hf_cwids_unknown1 = -1;
static int hf_cwids_channel = -1;
static int hf_cwids_unknown2 = -1;
static int hf_cwids_reallength = -1;
static int hf_cwids_capturelen = -1;
static int hf_cwids_unknown3 = -1;
static gint ett_cwids = -1;
static dissector_handle_t ieee80211_handle;
static void
dissect_cwids(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
tvbuff_t *wlan_tvb;
proto_tree *ti, *cwids_tree;
volatile int offset = 0;
guint16 capturelen;
void *pd_save;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CWIDS");
col_set_str(pinfo->cinfo, COL_INFO, "Cwids: ");
/* FIXME: col_set_fence(pinfo->cinfo, all-cols, only addr-cols?); */
cwids_tree = NULL;
while(tvb_length_remaining(tvb, offset) > 0) {
ti = proto_tree_add_item(tree, proto_cwids, tvb, offset, 28, ENC_NA);
cwids_tree = proto_item_add_subtree(ti, ett_cwids);
proto_tree_add_item(cwids_tree, hf_cwids_version, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cwids_tree, hf_cwids_unknown1, tvb, offset, 7, ENC_NA);
offset += 7;
proto_tree_add_item(cwids_tree, hf_cwids_channel, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item(cwids_tree, hf_cwids_unknown2, tvb, offset, 6, ENC_NA);
offset += 6;
proto_tree_add_item(cwids_tree, hf_cwids_reallength, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
capturelen = tvb_get_ntohs(tvb, offset);
proto_tree_add_item(cwids_tree, hf_cwids_capturelen, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cwids_tree, hf_cwids_unknown3, tvb, offset, 8, ENC_NA);
offset += 8;
wlan_tvb = tvb_new_subset(tvb, offset, capturelen, capturelen);
/* Continue after ieee80211 dissection errors */
pd_save = pinfo->private_data;
TRY {
call_dissector(ieee80211_handle, wlan_tvb, pinfo, tree);
} CATCH2(BoundsError, ReportedBoundsError) {
expert_add_info_format(pinfo, NULL,
PI_MALFORMED, PI_ERROR,
"Malformed or short IEEE80211 subpacket");
/* Restore the private_data structure in case one of the
* called dissectors modified it (and, due to the exception,
* was unable to restore it).
*/
pinfo->private_data = pd_save;
col_append_str(pinfo->cinfo, COL_INFO,
" [Malformed or short IEEE80211 subpacket] " );
col_set_fence(pinfo->cinfo, COL_INFO);
#if 0
wlan_tvb = tvb_new_subset(tvb, offset, capturelen, capturelen);
/* FIXME: Why does this throw an exception? */
proto_tree_add_text(cwids_tree, wlan_tvb, offset, capturelen,
"[Malformed or short IEEE80211 subpacket]");
#else
tvb_new_subset(tvb, offset, capturelen, capturelen);
#endif
;
} ENDTRY;
offset += capturelen;
}
}
void proto_register_cwids(void);
void proto_reg_handoff_cwids(void);
void
proto_register_cwids(void)
{
static hf_register_info hf[] = {
{ &hf_cwids_version,
{ "Capture Version", "cwids.version", FT_UINT16, BASE_DEC, NULL,
0x0, "Version or format of record", HFILL }},
{ &hf_cwids_unknown1,
{ "Unknown1", "cwids.unknown1", FT_BYTES, BASE_NONE, NULL,
0x0, "1st Unknown block - timestamp?", HFILL }},
{ &hf_cwids_channel,
{ "Channel", "cwids.channel", FT_UINT8, BASE_DEC, NULL,
0x0, "Channel for this capture", HFILL }},
{ &hf_cwids_unknown2,
{ "Unknown2", "cwids.unknown2", FT_BYTES, BASE_NONE, NULL,
0x0, "2nd Unknown block", HFILL }},
{ &hf_cwids_reallength,
{ "Original length", "cwids.reallen", FT_UINT16, BASE_DEC, NULL,
0x0, "Original num bytes in frame", HFILL }},
{ &hf_cwids_capturelen,
{ "Capture length", "cwids.caplen", FT_UINT16, BASE_DEC, NULL,
0x0, "Captured bytes in record", HFILL }},
{ &hf_cwids_unknown3,
{ "Unknown3", "cwids.unknown3", FT_BYTES, BASE_NONE, NULL,
0x0, "3rd Unknown block", HFILL }},
};
static gint *ett[] = {
&ett_cwids,
};
module_t *cwids_module;
proto_cwids = proto_register_protocol("Cisco Wireless IDS Captures", "CWIDS", "cwids");
proto_register_field_array(proto_cwids, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
cwids_module = prefs_register_protocol(proto_cwids, proto_reg_handoff_cwids);
prefs_register_uint_preference(cwids_module, "udp.port",
"CWIDS port",
"Set the destination UDP port Cisco wireless IDS messages",
10, &global_udp_port);
}
void
proto_reg_handoff_cwids(void)
{
static dissector_handle_t cwids_handle;
static guint saved_udp_port;
static gboolean initialized = FALSE;
if (!initialized) {
cwids_handle = create_dissector_handle(dissect_cwids, proto_cwids);
dissector_add_handle("udp.port", cwids_handle);
ieee80211_handle = find_dissector("wlan");
initialized = TRUE;
} else {
if (saved_udp_port != 0) {
dissector_delete_uint("udp.port", saved_udp_port, cwids_handle);
}
}
if (global_udp_port != 0) {
dissector_add_uint("udp.port", global_udp_port, cwids_handle);
}
saved_udp_port = global_udp_port;
}
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