162 lines
6.7 KiB
Groff
162 lines
6.7 KiB
Groff
.\"
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.\" Copyright (c) 1997, Jim Binkley
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by Jim Binkley
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.Dd July 7, 1997
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.Dt WL 4 i386
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.Os FreeBSD
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.Sh NAME
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.Nm wl
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.Nd T1 speed ISA/radio lan card
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.Sh SYNOPSIS
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.Cd "device wl0 at isa? port 0x300 irq 5"
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.Sh DESCRIPTION
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The
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.Nm
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driver controls a radio lan card system made originally by
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NCR, then ATT, now Lucent. The system is spread-spectrum radio
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at around 915 mhz (or 2.4 ghz). With the supplied omni-directional antennae,
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about 400 feet (indoors, more outdoors) can be covered in circumference.
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This card can talk to the companion (wlp0) pccard. Speeds vary
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from 1 megabit to theoretically 2 megabits (roughly T1 in speed).
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.Pp
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The card has three fundamental hardware
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units, a so-called PSA or programmable storage area, a radio modem,
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and a ethernet lan controller. The latter component is the
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ancient (and not very honorable) Intel 82586 ethernet chip.
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Fundamentally it appears to the operating system as an ethernet system,
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and speaks IEEE MAC addresses. The radio modem simply translates
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ethernet packets to/from radio packets, that are either at 2.4 Ghz
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or 915 mhz depending on the radio modem. It supports a collision
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avoidance scheme. The lan controller
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supports promiscuous mode, broadcast, and multicasting
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(although there is a glitch
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in the latter). "It thinks it is ethernet".
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.Pp
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How it is used
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depends on the kind of antennae deployed with it. Point to point
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applications are possible as are ethernet-like lan use. The vendor
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ships an omni-directional antennae that works in the
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vicinity of 400 feet (indoors).
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Point to point antennae can be purchased that will go miles.
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.Sh SETUP
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The card can either be initialized with the vendor supplied DOS setup software.
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Typically minimally an IRQ, port, and Network ID must be supplied.
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Michael Smith's
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.Xr wlconfig 8
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utility can now be used to do this work from
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the UNIX side. The card is "not" plug and play.
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The network id controls whether one set of cards can hear another.
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If different, cards will read physical packets, but they will be discarded
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by the radio modem.
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.Sh CONTROL
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In addition to the config utility, there are several sysctl
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switches that can be used to modify runtime parameters.
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The
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.Xr sysctl 8
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variables are as follows:
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.Bl -diag
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.It "machdep.wl_xmit_delay <useconds>"
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This variable will cause the driver to insert a delay on transmit.
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250 is the default. The delay should probably be a bit longer
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on faster cpus and less on slower cpus. It exists because the 82586
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was not designed to work with pentium-speed cpu systems and if overdriven
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will have copious xmit side errors.
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.It machdep.wl_ignore_nwid <0 | 1>
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This switch defaults to 0; i.e., the nwid is not ignored. It can
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be set to 1 to cause the nwid to not be used. This may be useful
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when the device is in promiscuous mode as one can watch for all
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packets and ignore nwid differences.
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.It machdep.wl_xmit_watch <milliseconds>
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This switch is not currently useful.
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.It machdep.wl_gather_snr <milliseconds>
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This switch is not currently useful.
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.Pp
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There is also a signal strength cache in the driver. It may be interrogated
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with
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.Xr wlconfig 8 .
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Incoming packets
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are checked for certain hardware radio-modem values including signal
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strength, silence, and quality, which range fro 0..63, 0..63, and 0..15
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respectively. Thus one can read out signal strenth values to see
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how close/far peer nodes are. The signal strength cache is indexed by
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sender MAC address.
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There are two sysctls that change how it filters packets. Both are on
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by default.
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.It machdep.wl_wlcache_mcastonly <0 | 1>
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By default this switch is on.
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It forces the cache to filter out
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unicast packets. Only broadcast or multicast packets are accepted.
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.It machdep.wl_wlcache_iponly <0 | 1>
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By default this switch is on. It forces the driver to discard non-IP
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packets and also stores the IP src address. ARP packets are ignored,
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as are any other network protocol barring IPv4 packets.
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.El
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.Sh CAVEATS
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The 82586 has numerous defects. It may experience transmit-side
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errors when modern faster cpus send packets at it faster than it can handle.
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The driver (and probably the chip) does not support an all multicast mode.
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As a result, it can be used with applications like
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.Xr mrouted 8 ,
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but it must go into promiscuous mode for that to work. The driver
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is slow to change modes from "normal" to promiscuous mode, presumably
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due to delays in the configuration code.
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.Sh SEE ALSO
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.Xr sysctl 8 ,
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.Xr wlconfig 8
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.Pp
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.Pa http://www.wavelan.com
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.Sh HISTORY
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The
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.Nm
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driver was written by
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.An Anders Klemets
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(thousands of years ago?) and
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appears to be based on an even older Intel 82586 driver. The 82586
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controller was one of the first (if not the first?) integrated lan
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controller on the block. That does not mean it was the best either.
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Anders ported and or created a driver for the ISA wavelan and PCCARD
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wavelan system too (wlp).
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.An Robert T. Morris, Jr.
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ported the Mach drivers to BSDI.
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.An Jim Binkley
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ported them to
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.Fx 2.1 .
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.An Michael Smith
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ported the wl driver only to 2.2.2. Jim and Michael have been
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maintaining them. The current state of the driver is NOT ANYONE'S
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FAULT. Thanks to
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.An Bernie Doehner
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and
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.An Robert Buaas
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for contributions.
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.Sh AUTHORS
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Too numerous to mention. See above.
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