HORST(8)

NAME
horst - Highly Optimized Radio Scanning Tool

SYNOPSIS
horst [-v] [-h] [-q] [-D] [-a] [-c file] [-C channel] [-i interface] [-t sec] [-V view] [-d ms] [-b bytes] [-M file] [-s] [-u] [-N] [-n IP] [-p port] [-o file] [-X name] [-x command] [-e mac] [-f pkt_name] [-m mode] [-B BSSID]

DESCRIPTION
horst is a small, lightweight IEEE802.11 wireless LAN analyzer with a text interface. Its basic function is similar to tcpdump, Wireshark or Kismet, but it's much smaller and shows different, aggregated information which is not easily available from other tools. It is mainly targeted at debugging wireless LANs with a focus on ad-hoc (IBSS) mode in larger mesh networks. It can be useful to get a quick overview of what's going on on all wireless LAN channels and to identify problems.

•   Shows signal values per station.

•   Calculates channel utilization ("usage") by adding up the amount of time the packets actually occupy the medium.

•   "Spectrum Analyzer" shows signal levels and usage per channel.

•   Text-based "graphical" packet history, with signal, packet type and physical rate

•   Shows all stations per ESSID and the live TSF per node as it is counting.

•   Detects IBSS "splits" (same ESSID but different BSSID - this is a common driver problem).

•   Statistics of packets/bytes per physical rate and per packet type.

•   Has some support for mesh protocols (OLSR and batman).

•   Can filter specific packet types, source MAC addresses or BSSIDs.

•   Client/server support for monitoring on remote nodes.

•   Can be controlled via a named pipe.

See MONITOR MODE below for more information about the network interface setup.

OPTIONS

-v  Show version.

-h  Show summary of options.

-q  Quiet mode. Don't show user interface. This is only useful in conjunction when running in server mode (-C) or writing to a file (-o).

-D  Show lot's of debugging output, including a full package dump. Only available when compiled with DEBUG=1.

-a  Always add virtual monitor interface. Don't try to set existing interface to monitor mode.

-c configfile
    Use configfile instead of the default "/etc/horst.conf".

-C channel
    Set inital channel (number not frequency).

-i intf
    Operate on the given network interface instead of the default "wlan0".

-t sec
    Timeout (remove) nodes after not receiving packets from them for this time in seconds (default: 60 sec).

-V view
    Display 'view'. Valid view names are "history", "hist", "essid", "statistics", "stats", "spectrum", "spec".

-d ms
    Display update interval. The default value of 100ms can be increased to reduce CPU load caused by redrawing the screen.

-b bytes
    Receive buffer size. The receive buffer size can be set to tune memory consumption and reduce lost packets under load.

-M filename
    MAC address to host name mapping file. The file can either be a dhcp.leases file from dnsmasq or contain mappings in the form "MAC<space>name" (e.g.: "00:01:02:03:04:05 test") line by line (default filename: /tmp/dhcp.leases).

-s  Show a poor mans "spectrum analyzer". The same can be achieved by running horst as normal and pressing the button 's' (Spec); then 'c' (Chan) and 'a' (Automatically change channel).

-u  Upper channel limit for the automatic channel change.

-N  Allow client connections. Server mode. Only one client connection is supported at the moment (default: off).

-n IP
    Connect to a horst instance running in server-mode at the specified IP address.

-p port
    Use the specified port (default: 4444) for client/server connections.

-o filename
    Write a information about each received packet into file. Note that you can send to STDOUT by using -o /dev/stdout. See OUTPUT FILE FORMAT below.

-X  Accept control commands on a named pipe (default /tmp/horst).

-X name
    Accept control commands on a named pipe with given name or set pipe name used with -x.

-x command
    Send control command to another horst process who was started with -X and then exit. Multiple commands can be concatenated with ';'. Currently implemented commands are:

    pause
        Pause horst processing

    resume
        Resume horst processing

    reset
        Reset all history, statistics and views

    channel=X
        Set channel channel number

    channel_scan=X
        Automatically change channels (1 or 0)

    channel_dwell=X
        Set channel dwell time when automatically changing channel (ms)

    channel_upper=X
        Set max channel when automatically changing channel

    outfile=X
        Write to outfile named X. If the file is already open, it is cleared and re-openend. If filename is not specified ("outfile=") any existing file is closed and no file is written.

-e MAC
    Filter all MAC addresses except these, to show only packets originating from the specified MAC addresses. This option can be specified multiple times.

-f pkt_type
    Filter all packets except these. This option can be specified multiple times. For valid packet names see NAMES AND ABBREVIATIONS below.

-m (AP|STA|ADH|PRB|WDS|UNKNOWN)
    Only show/include packets and nodes of this mode. Note that the mode is infered by the information of packets we received and it may take some time until a node is properly classified. This option can be specified multiple times.

-B BSSID
    Only show/include packets which belong to the given BSSID.

TEXT USER INTERFACE

The ncurses-based text interface tries to display a lot of information, so it may look confusing at first. Below we describe the different screens and options.

Main screen

    The initial (main) screen is split into three parts. The upper area shows a list of aggregated "node" information, the most useful information about each sender which was discovered, one per line:

        /   "Spinner" to show activity

        Pk  Percentage of this node's packets in relation to all received packets

        Re% Percentage of retried frames of all frames this node sent

        Cha Channel number

        Sig Signal value (RSSI) in dBm

        RAT Physical data rate

        TRANSMITTER
            MAC address of sender

        MODE
            Operating Mode (AP, AHD, PRB, STA, WDS), see "NAMES AND ABBREVIATIONS"

        ENCR
            Encryption (WPA1, WPA2, WEP)

        ESSID
            ESSID

        INFO
            Additional info like "BATMAN", IP address...

    The lower area shows a scrolling list of packets as they come in:

        Cha Channel number

        Sig Signal value (RSSI) in dBm

        RAT Physical data rate

        TRANSMITTER
            MAC address of sender

        BSSID
            BSSID

        TYPE
            Packet type, see "NAMES AND ABBREVIATIONS"

        INFO
            Additional info like ESSID, TFS, IP address...

    The lower right box shows bar graphs for:

        Signal
            of last received packet in green

        bps Bits per second of all received packets

        Usage
            Percentage of channel use

    The lower edge is the menu and status bar, it shows which keys to press for other screens. The status shows ">" when horst is running or "=" when it is paused, then "F" when any kind of filter is active, the Channel, the monitor interface in use and the time.

Pause ('p' or <space>)

    Can be used to pause/resume horst. When horst is paused it will loose packets received in the mean time.

Reset ('r')

    Clears all history and aggregated statistical data.

History ('h')

    The history screen scrolls from right to left and shows a bar for each packet indicating the signal level. In the line below that, the packet type is indicated by one character (See NAMES AND ABBREVIATIONS below) and the rough physical data rate is indicated below that in blue.

ESSID ('e')

    The ESSID screen groups information by ESSID and shows the mode (AP, IBSS), the MAC address of the sender, the BSSID, the TSF, the beacon interval, the channel, the signal, a "W" when encrytoion is used and the IP address if known.

Statistics ('a')

    The statistics screen groups packets by physical rate and by packet type and shows other kinds of aggregated and statistical information based on packets.

Spectrum Analyzer ('s')

    The "poor mans spectrum analyzer" screen is only really useful when horst is started with the -s option or the "Automatically change channel" option is selected in the "Chan" settings, or the config option channel_scan is set.

    It shows the available channels horizontally and vertical bars for each channel:

        Signal in green

        Physical rate in blue

        Channel usage in orange/brown

By pressing the 'n' key, the display can be changed to show only the average signal level on each channel and the last 4 digits of the MAC address of the individual nodes at the level (height) they were received. This can give a quick graphical overview of the distance of nodes.

Filters ('f')

    This configuration dialog can be used to define the active filters.

Channel Settings ('c')

    This configuration dialog can be used to change the channel changing behaviour of horst or to change to a different channel manually.

Sort ('o')

    Only active in the main screen, can be used to sort the node list in the upper area by Signal, Time, BSSID or Channel.

NAMES AND ABBREVIATIONS

802.11 standard frames

    Management frames
    a | ASOCRQ | Association request
    A | ASOCRP | Associaion response
    a | REASRQ | Reassociation request
    A | REASRP | Reassociation response
    p | PROBRQ | Probe request
    P | PROBRP | Probe response
    T | TIMING | Timing Advertisement
    B | BEACON | Beacon
    t | ATIM | ATIM
    D | DISASC | Disassociation
    u | AUTH | Authentication
    U | DEAUTH | Deauthentication
    C | ACTION | Action
    c | ACTNOA | Action No Ack

    Control frames
    w | CTWRAP | Control Wrapper
    b | BACKRQ | Block Ack Request
    B | BACK | Block Ack
    s | PSPOLL | PS-Poll
    R | RTS | RTS
    C | CTS | CTS
    K | ACK | ACK
    f | CFEND | CF-End
    f | CFENDK | CF-End + CF-Ack

    Data frames
    D | DATA | Data
    F | DCFACK | Data + CF-Ack
    F | DCFPLL | Data + CF-Poll
    F | DCFKPL | Data + CF-Ack + CF-Poll
    n | NULL | Null (no data)
    f | CFACK | CF-Ack (no data)
    f | CFPOLL | CF-Poll (no data)
    f | CFCKPL | CF-Ack + CF-Poll (no data)
    Q | QDATA | QoS Data
    F | QDCFCK | QoS Data + CF-Ack
    F | QDCFPL | QoS Data + CF-Poll
    F | QDCFKP | QoS Data + CF-Ack + CF-Poll
    N | QDNULL | QoS Null (no data)
    f | QCFPLL | QoS CF-Poll (no data)
    f | QCFKPL | QoS CF-Ack + CF-Poll (no data)
    * | BADFCS | Bad frame checksum

Packet types

    Similar to 802.11 frames above but higher level and as a bit field (types can overlap, e.g. DATA + IP) and including more information, like IP, ARP, BATMAN, OLSR...

    Packet types
    CTRL | 0x000001 | WLAN Control frame
    MGMT | 0x000002 | WLAN Management frame
    DATA | 0x000004 | WLAN Data frame
    BADFCS | 0x000008 | WLAN frame checksum (FCS) bad
    BEACON | 0x000010 | WLAN beacon frame
    PROBE | 0x000020 | WLAN probe request or response
    ASSOC | 0x000040 | WLAN associaction request/response frame
    AUTH | 0x000080 | WLAN authentication frame
    RTSCTS | 0x000100 | WLAN RTS or CTS
    ACK | 0x000200 | WLAN ACK or BlockACK
    NULL | 0x000400 | WLAN NULL Data frame
    QDATA | 0x000800 | WLAN QoS Data frame (WME/WMM)
    ARP | 0x001000 | ARP packet
    IP | 0x002000 | IP packet
    ICMP | 0x004000 | IP ICMP packet
    UDP | 0x008000 | IP UDP
    TCP | 0x010000 | IP TCP
    OLSR | 0x020000 | OLSR protocol
    BATMAN | 0x040000 | BATMAND Layer3 or BATMAN-ADV Layer 2 frame
    MESHZ | 0x080000 | MeshCruzer protocol

Operating modes

    Bit field of operating mode type which is infered from received packets. Modes may overlap, i.e. it is common to see STA and PRB at the same time.

    Operating modes
    AP | 0x01 | Access Point (AP)
    ADH | 0x02 | Ad-hoc node
    STA | 0x04 | Station (AP client)
    PRB | 0x08 | Sent PROBE requests
    WDS | 0x10 | WDS or 4 Address frames
    UNKNOWN | 0x20 | Unknown e.g. RTS/CTS or ACK

MONITOR MODE

To capture and analyze 802.11 traffic, the interface needs to be in monitor mode. You can either setup the interface manually beforehand or let horst setup it automatically at startup. Usually, root privileges are required to modify an interface setup.

horst should work with any wireleass LAN card and driver which supports monitor mode, with either "prism2" or "radiotap" headers. This includes most modern mac80211-based drivers.

If the interface is not in monitor mode at startup, horst first tries to put the interface in monitor mode. If it fails (for example when the interface is already in use), a new virtual monitor interface (horst0) is added and used instead. The virtual monitor interface is removed when horst exits. Note that changing the channel via a virtual monitor interface is not allowed by the wireless driver, so options -C and -s do not work when virtual monitor interface is used.

Examples of how to setup an interface manually:

Using iw:
    iw wlan0 interface add mon0 type monitor

    or

    sudo iw wlan1 set type monitor
    sudo iw wlan1 set channel 6

Using iwconfig:
    iwconfig wlan0 mode monitor
    iwconfig wlan0 channel 1
    ifconfig wlan0 up

Using madwifi:
    wlanconfig wlan0 create wlandev wifi0 wlanmode monitor

Using hostap:
    iwconfig wlan0 mode monitor
    iwpriv wlan0 monitor_type 1

NOTES

Signal values and ranges may differ between wireless drivers and versions.

OUTPUT FILE FORMAT

The format of the output file (-o flag) is a comma separated list of the following fields in the following order, one packet each line.

timestamp
    Local time, including microseconds (e.g. 2015-05-16 15:05:44.338806 +0300)

packet_type
    802.11 MAC packet type name as defined in the section "NAMES AND ABBREVIATIONS".

wlan_src
    Source MAC address

wlan_dst
    Destination MAC address

wlan_bssid
    BSSID

pkt_types
    Higher level packet name as defined in section "NAMES AND ABBREVIATIONS".

phy_signal
    Signal strength in dBm

wlan_len
    Packet length (MAC)

phy_rate
    Physical data rate

phy_freq
    Received while tuned to this frequency.

wlan_tsf
    TFS timer value

wlan_essid
    ESSID, network name

wlan_mode
    Operating modes as defined in "NAMES AND ABBREVIATIONS".

wlan_channel
    Channel number

wlan_wep
    Encryption in use

wlan_wpa
    WPA1 Encryption in use

wlan_rsn
    RSN (WPA2) Encryption in use

ip_src
    IP source address (if available)

ip_dst
    IP destionation address (if available)

SEE ALSO
horst.conf(5), tcpdump(1), wireshark(1), kismet(1), README, http://br1.einfach.org/tech/horst

AUTHOR
horst was written by Bruno Randolf <br1@einfach.org>.

This manual page was written by Antoine Beaupré <anarcat@debian.org>, for the Debian project (and may be used by others).