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.\" $OpenBSD: bridge.4,v 1.1 1999/02/26 17:01:36 jason Exp $
.\"
.\" Copyright (c) 1999 Jason L. Wright (jason@thought.net)
.\" All rights reserved.
.\"
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by Jason L. Wright
.\" 4. The name of the author may not be used to endorse or promote products
.\" derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
.\"
.Dd January 14, 1999
.Dt BRIDGE 4
.Os
.Sh NAME
.Nm bridge
.Nd Ethernet bridge interface
.Sh SYNOPSIS
.Cd pseudo-device bridge 2
.Sh DESCRIPTION
The
.Nm bridge
device allows an Ethernet bridge to be created between two or more interfaces.
The bridges provided by this interface are learning bridges with the ability
to do IP filtering, see
.Xr ipf 4 ,
before packets are forwarded by the bridge.
.Sh IOCTLS
A
.Nm bridge
interface responds to all of the
.Xr ioctl 2
calls specific to other interfaces listed in
.Xr netintro 4 .
The following
.Xr ioctl 2
calls are specific to
.Nm bridge
devices.
They are defined in
.Aq Pa sys/sockio.h .
.Pp
.Bl -tag -width SIOCBRDGIDX
.It Dv SIOCBRDGIDX
.Pq Li "struct ifbreq"
Retrieve a member interface from a bridge by index number (zero based).
The argument structure is defined as follows:
.Bd -literal -offset indent
struct ifbreq {
char ifbname[IFNAMSIZ]; /* bridge interface */
char ifsname[IFNAMSIZ]; /* member interface */
u_int32_t index; /* interface index */
};
.Ed
.Pp
To get a list of interface members, set index to zero, and perform sucessive
.Xr ioctl 2
calls with increasing values of index. When the call returns ENOENT,
there are no more interface members.
.It Dv SIOCBRDGADD
.Pq Li "struct ifbreq"
Add the interface named in ifsname to the bridge named in ifbname.
.It Dv SIOCBRDGDEL
.Pq Li "struct ifbreq"
Delete the interface named in ifsname from the bridge named in ifbname.
.It Dv SIOCBRDGRT
.Pq Li "struct ifbrtreq"
Retrieve a list of routes by index number (zero based).
The argument structure is defined as follows:
.Bd -literal -offset indent
struct ifbrtreq {
char ifbname[IFNAMSIZ]; /* bridge interface */
u_int32_t index; /* iteration index */
struct ether_addr dst; /* destination addr */
char ifsname[IFNAMSIZ]; /* destination ifs */
u_int16_t age; /* route age */
};
.El
.Sh ERRORS
If the
.Xr ioctl 2
call fails,
.Xr errno 2
is set to one of the following values:
.Bl -tag -width Er
.It Bq Eq ENOENT
For an add request, this means that the named interface is not configured
into the system.
For delete operation, it means that the named interface is not a member
of the bridge.
For an interface list or route list request, it means
that there is no route or interface that corresponds to the given index
number.
.It Bq Eq ENOMEM
Memory could not be allocated for an interface to be added to the bridge.
.It Bq Eq EEXIST
The named interface is already a member of the bridge.
.It Bq Eq EBUSY
The named interface is already a member of another bridge.
.It Bq Eq EINVAL
The named interface is not an Ethernet interface.
.It Bq Eq ENETDOWN
The named interface is not ready for receiving packets.
.It Bq Eq EPERM
Super-user privilege is required to add and delete interfaces to and from
bridges and to set the bridge interface flags.
.El
.Sh SEE ALSO
.Xr errno 2 ,
.Xr ioctl 2 ,
.Xr ipf 4 ,
.Xr netintro 4 ,
.Xr brconfig 8
.Sh AUTHOR
The
.Xr brconfig 8
command and the
.Xr bridge 4
kernel interface were written by Jason L. Wright <jason@thought.net> as
part of an undergraduate indenpendent study
at the University of North Carolina at Greensboro.
.Sh BUGS
There is currently no loop detection. Care must be taken to make sure
that loops are not created when a bridge is brought up.
.Sh HISTORY
The
.Xr brconfig 8
command and the
.Xr bridge 4
kernel interface first appeared in
.Ox 2.5 .
|
