c01dd585c7
All the NetMon reading code does is initialize the pseudo-header; the bulk of the work is done in the dissector. Give the dissector its own pseudo-header structure, and do the initialization there. That's the way other packet formats in which the 802.11 radio metadata is a header at the beginning of the packet data, such as radiotap, work.
444 lines
15 KiB
C
444 lines
15 KiB
C
/*
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* packet-ieee80211-netmon.c
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* Decode packets with a Network Monitor 802.11 radio header
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <wiretap/wtap.h>
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#include <wsutil/802_11-utils.h>
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void proto_register_netmon_802_11(void);
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void proto_reg_handoff_netmon_802_11(void);
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/* protocol */
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static int proto_netmon_802_11 = -1;
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/* Dissector */
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static dissector_handle_t netmon_802_11_handle;
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#define MIN_HEADER_LEN 32
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/* op_mode */
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#define OP_MODE_STA 0x00000001 /* station mode */
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#define OP_MODE_AP 0x00000002 /* AP mode */
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#define OP_MODE_STA_EXT 0x00000004 /* extensible station mode */
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#define OP_MODE_MON 0x80000000 /* monitor mode */
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/* phy_type */
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/*
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* Augmented with phy types from
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*
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* https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/content/windot11/ne-windot11-_dot11_phy_type
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*/
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#define PHY_TYPE_UNKNOWN 0
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#define PHY_TYPE_FHSS 1
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#define PHY_TYPE_DSSS 2
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#define PHY_TYPE_IR_BASEBAND 3
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#define PHY_TYPE_OFDM 4 /* 802.11a */
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#define PHY_TYPE_HR_DSSS 5 /* 802.11b */
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#define PHY_TYPE_ERP 6 /* 802.11g */
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#define PHY_TYPE_HT 7 /* 802.11n */
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#define PHY_TYPE_VHT 8 /* 802.11ac */
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static int hf_netmon_802_11_version = -1;
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static int hf_netmon_802_11_length = -1;
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static int hf_netmon_802_11_op_mode = -1;
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static int hf_netmon_802_11_op_mode_sta = -1;
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static int hf_netmon_802_11_op_mode_ap = -1;
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static int hf_netmon_802_11_op_mode_sta_ext = -1;
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static int hf_netmon_802_11_op_mode_mon = -1;
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/* static int hf_netmon_802_11_flags = -1; */
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static int hf_netmon_802_11_phy_type = -1;
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static int hf_netmon_802_11_channel = -1;
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static int hf_netmon_802_11_frequency = -1;
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static int hf_netmon_802_11_rssi = -1;
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static int hf_netmon_802_11_datarate = -1;
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static int hf_netmon_802_11_timestamp = -1;
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static gint ett_netmon_802_11 = -1;
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static gint ett_netmon_802_11_op_mode = -1;
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static dissector_handle_t ieee80211_radio_handle;
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static int
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dissect_netmon_802_11(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
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{
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struct ieee_802_11_phdr phdr;
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proto_tree *wlan_tree = NULL, *opmode_tree;
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proto_item *ti;
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tvbuff_t *next_tvb;
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int offset;
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guint8 version;
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guint16 length;
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guint32 phy_type;
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guint32 monitor_mode;
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guint32 flags;
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guint32 channel;
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gint calc_channel;
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gint32 rssi;
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guint8 rate;
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/*
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* It appears to be the case that management frames (and control and
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* extension frames ?) may or may not have an FCS and data frames don't.
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* (Netmon capture files have been seen for this encapsulation
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* management frames either completely with or without an FCS. Also:
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* instances have been seen where both Management and Control frames
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* do not have an FCS). An "FCS length" of -2 means "NetMon weirdness".
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*
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* The metadata header also has a bit indicating whether the adapter
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* was in monitor mode or not; if it isn't, we set "decrypted" to TRUE,
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* as, for those frames, the Protected bit is preserved in received
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* frames, but the frame is decrypted.
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*/
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memset(&phdr, 0, sizeof(phdr));
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phdr.fcs_len = -2;
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phdr.decrypted = FALSE;
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phdr.datapad = FALSE;
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phdr.phy = PHDR_802_11_PHY_UNKNOWN;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "WLAN");
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col_clear(pinfo->cinfo, COL_INFO);
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offset = 0;
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version = tvb_get_guint8(tvb, offset);
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length = tvb_get_letohs(tvb, offset+1);
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col_add_fstr(pinfo->cinfo, COL_INFO, "NetMon WLAN Capture v%u, Length %u",
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version, length);
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if (version != 2) {
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/* XXX - complain */
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goto skip;
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}
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if (length < MIN_HEADER_LEN) {
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/* XXX - complain */
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goto skip;
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}
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/* Dissect the packet */
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ti = proto_tree_add_item(tree, proto_netmon_802_11, tvb, 0, length,
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ENC_NA);
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wlan_tree = proto_item_add_subtree(ti, ett_netmon_802_11);
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/*
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* XXX - is this the NDIS_OBJECT_HEADER structure:
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*
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* https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/content/ntddndis/ns-ntddndis-_ndis_object_header
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*
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* at the beginning of a DOT11_EXTSTA_RECV_CONTEXT structure:
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*
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* https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/content/windot11/ns-windot11-dot11_extsta_recv_context
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*
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* If so, the byte at an offset of 0 would be the appropriate type for the
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* structure following it, i.e. NDIS_OBJECT_TYPE_DEFAULT.
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*/
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proto_tree_add_item(wlan_tree, hf_netmon_802_11_version, tvb, offset, 1,
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ENC_LITTLE_ENDIAN);
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offset += 1;
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proto_tree_add_item(wlan_tree, hf_netmon_802_11_length, tvb, offset, 2,
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ENC_LITTLE_ENDIAN);
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offset += 2;
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/*
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* This isn't in the DOT11_EXTSTA_RECV_CONTEXT structure.
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*/
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ti = proto_tree_add_item(wlan_tree, hf_netmon_802_11_op_mode, tvb, offset,
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4, ENC_LITTLE_ENDIAN);
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opmode_tree = proto_item_add_subtree(ti, ett_netmon_802_11_op_mode);
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proto_tree_add_item(opmode_tree, hf_netmon_802_11_op_mode_sta, tvb, offset,
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4, ENC_LITTLE_ENDIAN);
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proto_tree_add_item(opmode_tree, hf_netmon_802_11_op_mode_ap, tvb, offset,
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4, ENC_LITTLE_ENDIAN);
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proto_tree_add_item(opmode_tree, hf_netmon_802_11_op_mode_sta_ext, tvb,
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offset, 4, ENC_LITTLE_ENDIAN);
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proto_tree_add_item_ret_uint(opmode_tree, hf_netmon_802_11_op_mode_mon, tvb, offset,
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4, ENC_LITTLE_ENDIAN, &monitor_mode);
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if (!monitor_mode) {
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/*
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* If a NetMon capture is not done in monitor mode, we may see frames
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* with the Protect bit set (because they were encrypted on the air)
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* but that aren't encrypted (because they've been decrypted before
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* being written to the file). This wasn't done in monitor mode, as
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* the "monitor mode" flag wasn't set, so supporess treating the
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* Protect flag as an indication that the frame was encrypted.
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*/
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phdr.decrypted = TRUE;
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/*
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* Furthermore, we may see frames with the A-MSDU Present flag set
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* in the QoS Control field but that have a regular frame, nto a
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* sequence of A-MSDUs, in the payload.
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*/
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phdr.no_a_msdus = TRUE;
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}
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offset += 4;
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/*
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* uReceiveFlags?
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*/
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flags = tvb_get_letohl(tvb, offset);
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offset += 4;
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if (flags != 0xffffffff) {
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/*
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* uPhyId?
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*/
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phy_type = tvb_get_letohl(tvb, offset);
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memset(&phdr.phy_info, 0, sizeof(phdr.phy_info));
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/*
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* Unlike the channel flags in radiotap, this appears
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* to correctly indicate the modulation for this packet
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* (no cases seen where this doesn't match the data rate).
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*/
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switch (phy_type) {
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case PHY_TYPE_UNKNOWN:
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phdr.phy = PHDR_802_11_PHY_UNKNOWN;
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break;
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case PHY_TYPE_FHSS:
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phdr.phy = PHDR_802_11_PHY_11_FHSS;
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break;
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case PHY_TYPE_IR_BASEBAND:
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phdr.phy = PHDR_802_11_PHY_11_IR;
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break;
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case PHY_TYPE_DSSS:
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phdr.phy = PHDR_802_11_PHY_11_DSSS;
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break;
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case PHY_TYPE_HR_DSSS:
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phdr.phy = PHDR_802_11_PHY_11B;
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break;
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case PHY_TYPE_OFDM:
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phdr.phy = PHDR_802_11_PHY_11A;
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break;
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case PHY_TYPE_ERP:
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phdr.phy = PHDR_802_11_PHY_11G;
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break;
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case PHY_TYPE_HT:
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phdr.phy = PHDR_802_11_PHY_11N;
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break;
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case PHY_TYPE_VHT:
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phdr.phy = PHDR_802_11_PHY_11AC;
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break;
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default:
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phdr.phy = PHDR_802_11_PHY_UNKNOWN;
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break;
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}
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proto_tree_add_item(wlan_tree, hf_netmon_802_11_phy_type, tvb, offset, 4,
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ENC_LITTLE_ENDIAN);
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offset += 4;
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/*
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* uChCenterFrequency?
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*/
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channel = tvb_get_letohl(tvb, offset);
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if (channel < 1000) {
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if (channel == 0) {
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proto_tree_add_uint_format_value(wlan_tree, hf_netmon_802_11_channel,
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tvb, offset, 4, channel,
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"Unknown");
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} else {
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guint frequency;
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phdr.has_channel = TRUE;
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phdr.channel = channel;
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proto_tree_add_uint(wlan_tree, hf_netmon_802_11_channel,
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tvb, offset, 4, channel);
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switch (phdr.phy) {
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case PHDR_802_11_PHY_11B:
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case PHDR_802_11_PHY_11G:
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/* 2.4 GHz channel */
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frequency = ieee80211_chan_to_mhz(channel, TRUE);
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break;
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case PHDR_802_11_PHY_11A:
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/* 5 GHz channel */
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frequency = ieee80211_chan_to_mhz(channel, FALSE);
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break;
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default:
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frequency = 0;
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break;
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}
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if (frequency != 0) {
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phdr.has_frequency = TRUE;
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phdr.frequency = frequency;
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}
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}
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} else {
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phdr.has_frequency = TRUE;
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phdr.frequency = channel;
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proto_tree_add_uint(wlan_tree, hf_netmon_802_11_frequency,
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tvb, offset, 4, channel);
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calc_channel = ieee80211_mhz_to_chan(channel);
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if (calc_channel != -1) {
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phdr.has_channel = TRUE;
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phdr.channel = calc_channel;
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}
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}
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offset += 4;
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/*
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* usNumberOfMPDUsReceived is missing.
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*/
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/*
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* lRSSI?
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*/
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rssi = tvb_get_letohl(tvb, offset);
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if (rssi == 0) {
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proto_tree_add_int_format_value(wlan_tree, hf_netmon_802_11_rssi,
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tvb, offset, 4, rssi,
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"Unknown");
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} else {
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phdr.has_signal_dbm = TRUE;
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phdr.signal_dbm = rssi;
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proto_tree_add_int_format_value(wlan_tree, hf_netmon_802_11_rssi,
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tvb, offset, 4, rssi,
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"%d dBm", rssi);
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}
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offset += 4;
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/*
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* ucDataRate?
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*/
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rate = tvb_get_guint8(tvb, offset);
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if (rate == 0) {
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proto_tree_add_uint_format_value(wlan_tree, hf_netmon_802_11_datarate,
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tvb, offset, 1, rate,
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"Unknown");
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} else {
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phdr.has_data_rate = TRUE;
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phdr.data_rate = rate;
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proto_tree_add_uint_format_value(wlan_tree, hf_netmon_802_11_datarate,
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tvb, offset, 1, rate,
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"%f Mb/s", rate*.5);
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}
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offset += 1;
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} else
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offset += 13;
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/*
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* ullTimestamp?
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*
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* If so, should this check the presense flag in flags?
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*/
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phdr.has_tsf_timestamp = TRUE;
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phdr.tsf_timestamp = tvb_get_letoh64(tvb, offset);
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proto_tree_add_item(wlan_tree, hf_netmon_802_11_timestamp, tvb, offset, 8,
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ENC_LITTLE_ENDIAN);
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/*offset += 8;*/
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skip:
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offset = length;
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/* dissect the 802.11 packet next */
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next_tvb = tvb_new_subset_remaining(tvb, offset);
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call_dissector_with_data(ieee80211_radio_handle, next_tvb, pinfo, tree, &phdr);
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return offset;
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}
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void
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proto_register_netmon_802_11(void)
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{
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static const value_string phy_type[] = {
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{ PHY_TYPE_UNKNOWN, "Unknown" },
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{ PHY_TYPE_FHSS, "802.11 FHSS" },
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{ PHY_TYPE_DSSS, "802.11 DSSS" },
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{ PHY_TYPE_IR_BASEBAND, "802.11 IR" },
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{ PHY_TYPE_OFDM, "802.11a" },
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{ PHY_TYPE_HR_DSSS, "802.11b" },
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{ PHY_TYPE_ERP, "802.11g" },
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{ PHY_TYPE_HT, "802.11n" },
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{ PHY_TYPE_VHT, "802.11ac" },
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{ 0, NULL },
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};
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static hf_register_info hf[] = {
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{ &hf_netmon_802_11_version, { "Header revision", "netmon_802_11.version", FT_UINT8,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_length, { "Header length", "netmon_802_11.length", FT_UINT16,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_op_mode, { "Operation mode", "netmon_802_11.op_mode", FT_UINT32,
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BASE_HEX, NULL, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_op_mode_sta, { "Station mode", "netmon_802_11.op_mode.sta", FT_UINT32,
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BASE_HEX, NULL, OP_MODE_STA, NULL, HFILL } },
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{ &hf_netmon_802_11_op_mode_ap, { "AP mode", "netmon_802_11.op_mode.ap", FT_UINT32,
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BASE_HEX, NULL, OP_MODE_AP, NULL, HFILL } },
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{ &hf_netmon_802_11_op_mode_sta_ext, { "Extensible station mode", "netmon_802_11.op_mode.sta_ext", FT_UINT32,
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BASE_HEX, NULL, OP_MODE_STA_EXT, NULL, HFILL } },
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{ &hf_netmon_802_11_op_mode_mon, { "Monitor mode", "netmon_802_11.op_mode.mon", FT_UINT32,
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BASE_HEX, NULL, OP_MODE_MON, NULL, HFILL } },
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#if 0
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{ &hf_netmon_802_11_flags, { "Flags", "netmon_802_11.flags", FT_UINT32,
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BASE_HEX, NULL, 0x0, NULL, HFILL } },
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#endif
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{ &hf_netmon_802_11_phy_type, { "PHY type", "netmon_802_11.phy_type", FT_UINT32,
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BASE_DEC, VALS(phy_type), 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_channel, { "Channel", "netmon_802_11.channel", FT_UINT32,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_frequency, { "Center frequency", "netmon_802_11.frequency", FT_UINT32,
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BASE_DEC|BASE_UNIT_STRING, &units_mhz, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_rssi, { "RSSI", "netmon_802_11.rssi", FT_INT32,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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{ &hf_netmon_802_11_datarate, { "Data rate", "netmon_802_11.datarate", FT_UINT32,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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/*
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* XXX - is this host, or MAC, time stamp?
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* It might be a FILETIME.
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*/
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{ &hf_netmon_802_11_timestamp, { "Timestamp", "netmon_802_11.timestamp", FT_UINT64,
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BASE_DEC, NULL, 0x0, NULL, HFILL } },
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};
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static gint *ett[] = {
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&ett_netmon_802_11,
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&ett_netmon_802_11_op_mode
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};
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proto_netmon_802_11 = proto_register_protocol("NetMon 802.11 capture header",
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"NetMon 802.11",
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"netmon_802_11");
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netmon_802_11_handle = register_dissector("netmon_802_11", dissect_netmon_802_11, proto_netmon_802_11);
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proto_register_field_array(proto_netmon_802_11, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_netmon_802_11(void)
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{
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/* handle for 802.11+radio information dissector */
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ieee80211_radio_handle = find_dissector_add_dependency("wlan_radio", proto_netmon_802_11);
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dissector_add_uint("wtap_encap", WTAP_ENCAP_IEEE_802_11_NETMON, netmon_802_11_handle);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=2 tabstop=8 expandtab:
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|
* :indentSize=2:tabSize=8:noTabs=true:
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|
*/
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