usr.sbin/wlanctl/wlanctl.8

.\" $NetBSD: wlanctl.8,v 1.3 2005/01/27 21:01:18 hubertf Exp $
.\" Copyright (c) 2004 David Young.  All rights reserved.
.\"
.\" This code was written by David Young.
.\"
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.Dd July 15, 2004
.Dt WLANCTL 8
.Os
.Sh NAME
.Nm wlanctl
.Nd examine IEEE 802.11 wireless LAN client/peer table
.Sh SYNOPSIS
.Nm wlanctl
.Ar interface
.Op Ar ...
.Nm
.Fl a
.Sh DESCRIPTION
Use the
.Nm
utility to print node tables from IEEE 802.11 interfaces.
Use the
.Fl a
flag to print the nodes for all interfaces, or list one or more
802.11 interfaces to select their tables for examination.
For example, to examine the node tables for atw0, use:
.Pp
.Bd -literal -offset indent -compact
wlanctl atw0
.Ed
.Pp
.Nm
may print this node table, for example:
.Pp
.Bd -literal -offset indent -compact
atw0: mac 00:02:6f:20:f6:2e bss 02:02:6f:20:f6:2e
	node flags 0001\*[Lt]bss\*[Gt]
	ess \*[Lt]netbsd\*[Gt]
	chan 11 freq 2462MHz flags 00a0\*[Lt]cck,2.4GHz\*[Gt]
	capabilities 0022\*[Lt]ibss,short preamble\*[Gt]
	beacon-interval 100 TU tsft 18425852102545544165 us
	rates [1.0] 2.0 5.5 11.0
	assoc-id 0 assoc-failed 0 inactivity 0s
	rssi 161 txseq 10 rxseq 1420
atw0: mac 00:02:2d:2e:3c:f4 bss 02:02:6f:20:f6:2e
	node flags 0000
	ess \*[Lt]netbsd\*[Gt]
	chan 11 freq 2462MHz flags 00a0\*[Lt]cck,2.4GHz\*[Gt]
	capabilities 0002\*[Lt]ibss\*[Gt]
	beacon-interval 100 TU tsft 18425852105450086784 us
	rates [1.0] 2.0 5.5 11.0
	assoc-id 0 assoc-failed 0 inactivity 0s
	rssi 159 txseq 2 rxseq 551
atw0: mac 00:02:6f:20:f6:2e bss 02:02:6f:20:f6:2e
	node flags 0000
	ess \*[Lt]netbsd\*[Gt]
	chan 11 freq 2462MHz flags 00a0\*[Lt]cck,2.4GHz\*[Gt]
	capabilities 0022\*[Lt]ibss,short preamble\*[Gt]
	beacon-interval 100 TU tsft 18425852102558548069 us
	rates [1.0] 2.0 5.5 6.0 9.0 11.0 12.0 18.0 24.0 36.0 48.0 54.0
	assoc-id 0 assoc-failed 0 inactivity 145s
	rssi 163 txseq 9 rxseq 2563
.Ed
.Pp
This example is taken from a network consisting of three stations
running in ad hoc mode.
The key for interpreting the node print-outs follows:
.Bl -tag -width "do_not_adapt" -compact
.It Fa mac
In the example node table, the first network node has MAC number
00:02:6f:20:f6:2e.
.It Fa bss
The first node belongs to the 802.11 network identified
by Basic Service Set Identifier (BSSID) 02:02:6f:20:f6:2e.
.It Fa "node flags"
Only one node flag,
.Dq bss ,
is presently defined.
The first node is distinguished from the rest by its node flags:
flag
.Dq bss
indicates that the node represents the 802.11 network
that the interface has joined or created.
The MAC number for the node is the same as the MAC number for the
interface.
.It Fa ess
the name of the (Extended) Service Set
we have joined.
This is the same as the network name set by
.Xr ifconfig 8
with the
.Dq ssid
option.
.It Fa chan
.Nm
prints the channel number, the center frequency in megahertz, and
the channel flags.
The channel flags indicate the frequency band (
.Po Dq 2.4GHz
or
.Dq 5GHz Pc ,
modulation
.Po Dq cck ,
.Dq gfsk ,
.Dq ofdm ,
.Dq turbo ,
and
.Dq dynamic cck-ofdm Pc ,
and operation constraints
.Pq Dq passive scan .
Common combinations of band and modulation are these:
.Bl -column 2.4GHz "dynamic cck-ofdm" "1-2Mb/s frequency-hopping 802.11"
.It Sy Band	Modulation	Description
.It 2.4GHz	cck	11Mb/s DSSS 802.11b
.It 2.4GHz	gfsk	1-2Mb/s FHSS 802.11
.It 2.4GHz	ofdm	54Mb/s 802.11g
.It 2.4GHz	dynamic cck-ofdm	mixed 802.11b/g network
.It 5GHz	ofdm	54Mb/s 802.11a
.It 5GHz	turbo	108Mb/s 802.11a
.El
.It Fa capabilities
ad hoc-mode and AP-mode 802.11 stations advertise their capabilities
in 802.11 Beacons and Probe Responses.
.Nm
understands these capability flags:
.Bl -column "channel agility" "adapt channel to protect licensed services"
.It Sy Flag	Description
.It ess	infrastructure (access point) network
.It ibss	ad hoc network (no access point)
.It cf pollable	TBD
.It request cf poll	TBD
.It privacy	WEP encryption
.It short preamble	reduce 802.11b overhead
.It pbcc	22Mbps ``802.11b+''
.It channel agility	change channel for licensed services
.It short slot-time	TBD
.It rsn	TBD Real Soon Now
.It dsss-ofdm	TBD
.El
.It Fa beacon-interval
In the example, beacons are sent once every 100 Time Units.
A Time Unit (TU) is 1024 microseconds (a
.Dq kilo-microsecond
or
.Dq kus ) .
Thus 100 TU is about one tenth of a second.
.It Fa tsft
802.11 stations keep a Time Synchronization Function Timer (TSFT)
which counts up in microseconds.
Ad hoc-mode stations synchronize time with their peers.
Infrastructure-mode stations synchronize time with their access
point.
Power-saving stations wake and sleep at intervals measured by the
TSF Timer.
The TSF Timer has a role in the coalescence of 802.11 ad hoc networks
.Pq Dq IBSS merges .
.It Fa rates
802.11 stations indicate the bit-rates they support, in units of
100kb/s in 802.11 Beacons, Probe Responses, and Association Requests.
.Nm
prints a station's supported bit-rates in 1Mb/s units.
A station's basic rates are flagged by an asterisk
.Pq Sq * .
The last bit-rate at which a packet was sent to the station is
enclosed by square brackets.
.It Fa assoc-id
In an infrastructure network, the access point assigns each client
an Association Identifier which is used to indicate traffic for
power-saving stations.
.It Fa assoc-failed
The number of times the station tried and failed to associate
with its access point.
Only
.It Fa inactivity
Seconds elapsed since a packet was last received from the station.
When this value reaches net.link.ieee80211.maxinact, the station
is eligible to be purged from the node table.
See
.Xr sysctl 8 .
.It Fa rssi
Unitless Received Signal Strength Indication (RSSI).
Higher numbers indicate stronger signals.
Zero is the lowest possible RSSI.
On a hostap- or adhoc-mode interface, the node with
.Fa "node flag"
.Dq bss
set uses
.Fa rssi
to indicate the signal strength for the last packet received from
a station that does not belong to the network.
On an infrastructure-mode station, the node with
.Fa "node flag"
.Dq bss
set indicates the strength of packets from the access point.
.It Fa txseq
The next 802.11 packet sent to this station will carry this transmit
sequence number.
The 802.11 MAC uses the transmit sequence number to detect duplicate
packets.
.It Fa rxseq
The last packet received from this station carried this transmit
sequence number.
.El
.Sh SEE ALSO
.Xr sysctl 8
.Sh HISTORY
.Nm
first appeared in
.Nx 3.0 .
.Sh AUTHORS
.An David Young Aq dyoung@NetBSD.org