/* packet-cwids.c

 * Routines for dissecting wireless ids packets sent from a Cisco

 * access point to the WLSE (or whatever)

 *

 * Copyright 2006 Joerg Mayer (see AUTHORS file)

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

/* 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?

 */

#include "config.h"

#include <wiretap/wtap.h>

#include <epan/packet.h>

#include <epan/exceptions.h>

#include <epan/expert.h>

#include <epan/show_exception.h>

static int proto_cwids;

static int hf_cwids_version;

static int hf_cwids_timestamp;

static int hf_cwids_unknown1;

static int hf_cwids_channel;

static int hf_cwids_unknown2;

static int hf_cwids_reallength;

static int hf_cwids_capturelen;

static int hf_cwids_unknown3;

static int ett_cwids;

static expert_field ei_ieee80211_subpacket;

static dissector_handle_t cwids_handle;

static dissector_handle_t ieee80211_radio_handle;

static int

dissect_cwids(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  tvbuff_t *wlan_tvb;

  proto_tree *ti, *cwids_tree;

  volatile int offset = 0;

  uint16_t capturelen;

  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_reported_length_remaining(tvb, offset) > 0) {

    struct ieee_802_11_phdr phdr;

    ti = proto_tree_add_item(tree, proto_cwids, tvb, offset, 28, ENC_NA);

    cwids_tree = proto_item_add_subtree(ti, ett_cwids);

    memset(&phdr, 0, sizeof(phdr));

    phdr.fcs_len = 0; /* no FCS */

    phdr.decrypted = false;

    phdr.datapad = false;

    phdr.phy = PHDR_802_11_PHY_UNKNOWN;

    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_timestamp, tvb, offset, 6, ENC_NA);

    offset += 6;

    proto_tree_add_item(cwids_tree, hf_cwids_unknown1, tvb, offset, 1, ENC_NA);

    offset += 1;

    phdr.has_channel = true;

    phdr.channel = tvb_get_uint8(tvb, offset);

    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_length(tvb, offset, capturelen);

    /* Continue after ieee80211 dissection errors */

    TRY {

      call_dissector_with_data(ieee80211_radio_handle, wlan_tvb, pinfo, tree, &phdr);

    } CATCH_BOUNDS_ERRORS {

      show_exception(wlan_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);

      expert_add_info(pinfo, ti, &ei_ieee80211_subpacket);

    } ENDTRY;

    offset += capturelen;

  }

  return tvb_captured_length(tvb);

}

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_timestamp,

    { "Timestamp [us]", "cwids.timestamp", FT_BYTES, BASE_NONE, NULL,

      0x0, NULL, HFILL }},

    { &hf_cwids_unknown1,

    { "Unknown1", "cwids.unknown1", FT_BYTES, BASE_NONE, NULL,

      0x0, "1st Unknown block", 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 int *ett[] = {

    &ett_cwids,

  };

  static ei_register_info ei[] = {

    { &ei_ieee80211_subpacket, { "cwids.ieee80211_malformed", PI_MALFORMED, PI_ERROR, "Malformed or short IEEE80211 subpacket", EXPFILL }},

  };

  expert_module_t* expert_cwids;

  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));

  expert_cwids = expert_register_protocol(proto_cwids);

  expert_register_field_array(expert_cwids, ei, array_length(ei));

  cwids_handle = register_dissector("cwids", dissect_cwids, proto_cwids);

}

void

proto_reg_handoff_cwids(void)

{

  dissector_add_for_decode_as_with_preference("udp.port", cwids_handle);

  ieee80211_radio_handle = find_dissector_add_dependency("wlan_noqos_radio", proto_cwids);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 8

 * tab-width: 8

 * indent-tabs-mode: t

 * End:

 *

 * vi: set shiftwidth=8 tabstop=8 noexpandtab:

 * :indentSize=8:tabSize=8:noTabs=false:

 */