Merge from p4: CH154790,154793,154874

  Import if_epair(4), a virtual cross-over Ethernet-like interface pair.

Note these files are 1:1 from p4 and not yet connected to the build
not knowing about the new netisr interface.

Sponsored by:	The FreeBSD Foundation

1 files changed, 120 insertions, 0 deletions

diff --git a/share/man/man4/epair.4 b/share/man/man4/epair.4
new file mode 100644
index 0000000..b93d36e
--- /dev/null
+++ b/share/man/man4/epair.4
@@ -0,0 +1,120 @@
+.\"-
+.\" Copyright (c) 2008 The FreeBSD Foundation
+.\" All rights reserved.
+.\"
+.\" This software was developed by CK Software GmbH under sponsorship
+.\" from the FreeBSD Foundation.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd December 15, 2008
+.Dt EPAIR 4
+.Os
+.Sh NAME
+.Nm epair
+.Nd Virtual cross-over Ethernet-like interface pair.
+.Sh SYNOPSIS
+To compile this driver into the kernel,
+place the following line in your
+kernel configuration file:
+.Bd -ragged -offset indent
+.Cd "device epair"
+.Ed
+.Pp
+Alternatively, to load the driver as a
+module at boot time, place the following line in
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+if_epair_load="YES"
+.Ed
+.Sh DESCRIPTION
+The
+.Nm
+is a pair of Ethernet-like software interfaces,
+which are directly connected by a virtual cross-over cable.
+.Pp
+Each
+.Nm
+interface pair is created at runtime using interface cloning.
+This is most easily done with the
+.Xr ifconfig 8
+.Cm create
+command or using the
+.Va cloned_interfaces
+variable in
+.Xr rc.conf 5 .
+While for cloning you only give either
+.Pa epair
+or
+.Pa epair<n>
+the
+.Nm
+pair will be named like
+.Pa epair<n>[ab] .
+This means the names of the first
+.Nm
+interfaces will be
+.Pa epair0a
+and
+.Pa epair0b .
+.Pp
+Like any other Ethernet interface, an
+.Nm
+needs to have a network address.
+Each
+.Nm
+will be assigned a locally administered address by default,
+that is only guaranteed to be unique within one network stack.
+To change the default addresses one may use the SIOCSIFADDR ioctl(2) or
+ifconfig(8) utility.
+.Pp
+The basic intend is to provide connectivity between two virtual
+network stack instances.
+When connected to a
+.Xr if_bridge 4
+one end of the interface pair can also be part of another (virtual) LAN.
+As with any other Ethernet interface one can configure
+.Xr vlan 4
+support on top of it.
+.Pp
+.Sh SEE ALSO
+.Xr ioctl 2 ,
+.Xr altq 4 ,
+.Xr bpf 4 ,
+.Xr if_bridge 4 ,
+.Xr vlan 4 ,
+.Xr loader.conf 5, 
+.Xr rc.conf 5 ,
+.Xr ifconfig 8
+.Sh HISTORY
+The
+.Nm
+interface first appeared in
+.Fx 8.0 .
+.Sh AUTHORS
+The
+.Nm
+interface was written by
+.An Bjoern A. Zeeb, CK Software GmbH,
+under sponsorship from the FreeBSD Foundation.