135 lines
3.8 KiB
Groff
135 lines
3.8 KiB
Groff
.\" Copyright (c) 1996-1999 Whistle Communications, Inc.
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.\" All rights reserved.
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.\"
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.\" Subject to the following obligations and disclaimer of warranty, use and
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.\" redistribution of this software, in source or object code forms, with or
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.\" without modifications are expressly permitted by Whistle Communications;
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.\" provided, however, that:
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.\" 1. Any and all reproductions of the source or object code must include the
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.\" copyright notice above and the following disclaimer of warranties; and
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.\" 2. No rights are granted, in any manner or form, to use Whistle
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.\" Communications, Inc. trademarks, including the mark "WHISTLE
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.\" COMMUNICATIONS" on advertising, endorsements, or otherwise except as
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.\" such appears in the above copyright notice or in the software.
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.\"
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.\" THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
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.\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
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.\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
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.\" INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
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.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
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.\" WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
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.\" REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
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.\" SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
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.\" IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
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.\" RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
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.\" WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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.\" PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
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.\" OF SUCH DAMAGE.
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.\"
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.\" Author: Archie Cobbs <archie@FreeBSD.org>
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.\"
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.\" $FreeBSD$
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.\" $Whistle: ng_tee.8,v 1.4 1999/01/25 23:46:27 archie Exp $
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.\"
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.Dd May 28, 2004
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.Dt NG_TEE 4
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.Os
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.Sh NAME
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.Nm ng_tee
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.Nd netgraph ``tee'' node type
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.Sh SYNOPSIS
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.In sys/types.h
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.In netgraph/ng_tee.h
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.Sh DESCRIPTION
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The
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.Nm tee
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node type has a purpose similar to the
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.Xr tee 1
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command.
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.Nm Tee
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nodes are useful for debugging or
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.Dq snooping
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on a connection
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between two netgraph nodes.
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.Nm Tee
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nodes have four hooks,
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.Dv right ,
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.Dv left ,
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.Dv right2left ,
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and
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.Dv left2right .
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All data received on
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.Dv right
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is sent unmodified to
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.Em both
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hooks
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.Dv left
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and
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.Dv right2left .
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Similarly, all data received on
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.Dv left
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is sent unmodified to both
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.Dv right
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and
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.Dv left2right .
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.Pp
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Packets may also be received on
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.Dv right2left
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and
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.Dv left2right ;
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if so, they are forwarded unchanged out hooks
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.Dv right
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and
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.Dv left ,
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respectively.
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.Sh HOOKS
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This node type supports the following hooks:
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.Bl -tag -width ".Va left2right"
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.It Va right
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The connection to the node on the right.
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.It Va left
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The connection to the node on the left.
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.It Va right2left
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Tap for right to left traffic.
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.It Va left2right
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Tap for left to right traffic.
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.El
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.Sh CONTROL MESSAGES
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This node type supports the generic control messages, plus the following.
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.Bl -tag -width foo
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.It Dv NGM_TEE_GET_STATS Pq Ic getstats
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Get statistics, returned as a
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.Dv "struct ng_tee_stats" .
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.It Dv NGM_TEE_CLR_STATS Pq Ic clrstats
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Clear statistics.
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of an
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.Dv NGM_SHUTDOWN
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control message, or when all hooks have been disconnected.
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If both
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.Dv right
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and
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.Dv left
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hooks are present, node removes itself from the chain gently,
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connecting
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.Dv right
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and
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.Dv left
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together.
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.Sh SEE ALSO
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.Xr tee 1 ,
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.Xr netgraph 4 ,
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.Xr ngctl 8
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.Sh HISTORY
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The
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.Nm
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node type was implemented in
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.Fx 4.0 .
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.Sh AUTHORS
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.An Julian Elischer Aq Mt julian@FreeBSD.org
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