121 lines
3.3 KiB
Groff
121 lines
3.3 KiB
Groff
.\"-
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.\" Copyright (c) 2008 The FreeBSD Foundation
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.\" All rights reserved.
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.\"
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.\" This software was developed by CK Software GmbH under sponsorship
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.\" from the FreeBSD Foundation.
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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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.\"
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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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.\"
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.Dd July 26, 2009
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.Dt EPAIR 4
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.Os
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.Sh NAME
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.Nm epair
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.Nd A pair of virtual back-to-back connected Ethernet interfaces.
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.Sh SYNOPSIS
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To compile this driver into the kernel,
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place the following line in your
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kernel configuration file:
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.Bd -ragged -offset indent
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.Cd "device epair"
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.Ed
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.Pp
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Alternatively, to load the driver as a
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module at boot time, place the following line in
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.Xr loader.conf 5 :
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.Bd -literal -offset indent
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if_epair_load="YES"
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.Ed
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.Sh DESCRIPTION
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The
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.Nm
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is a pair of Ethernet-like software interfaces,
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which are connected back-to-back with a virtual cross-over cable.
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.Pp
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Each
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.Nm
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interface pair is created at runtime using interface cloning.
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This is most easily done with the
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.Xr ifconfig 8
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.Cm create
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command or using the
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.Va cloned_interfaces
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variable in
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.Xr rc.conf 5 .
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While for cloning you only give either
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.Pa epair
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or
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.Pa epair<n>
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the
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.Nm
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pair will be named like
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.Pa epair<n>[ab] .
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This means the names of the first
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.Nm
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interfaces will be
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.Pa epair0a
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and
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.Pa epair0b .
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.Pp
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Like any other Ethernet interface, an
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.Nm
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needs to have a network address.
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Each
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.Nm
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will be assigned a locally administered address by default,
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that is only guaranteed to be unique within one network stack.
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To change the default addresses one may use the SIOCSIFADDR ioctl(2) or
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ifconfig(8) utility.
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.Pp
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The basic intend is to provide connectivity between two virtual
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network stack instances.
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When connected to a
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.Xr if_bridge 4
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one end of the interface pair can also be part of another (virtual) LAN.
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As with any other Ethernet interface one can configure
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.Xr vlan 4
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support on top of it.
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.Pp
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.Sh SEE ALSO
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.Xr ioctl 2 ,
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.Xr altq 4 ,
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.Xr bpf 4 ,
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.Xr if_bridge 4 ,
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.Xr vlan 4 ,
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.Xr loader.conf 5 ,
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.Xr rc.conf 5 ,
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.Xr ifconfig 8
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.Sh HISTORY
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The
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.Nm
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interface first appeared in
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.Fx 8.0 .
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.Sh AUTHORS
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The
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.Nm
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interface was written by
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.An Bjoern A. Zeeb, CK Software GmbH,
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under sponsorship from the FreeBSD Foundation.
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