173 lines
5.8 KiB
Groff
173 lines
5.8 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_iface.8,v 1.5 1999/01/25 23:46:26 archie Exp $
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.\"
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.Dd February 6, 2019
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.Dt NG_IFACE 4
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.Os
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.Sh NAME
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.Nm ng_iface
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.Nd interface netgraph node type
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.Sh SYNOPSIS
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.In netgraph/ng_iface.h
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.Sh DESCRIPTION
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An
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.Nm iface
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node is both a netgraph node and a system networking interface.
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When an
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.Nm iface
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node is created, a new interface appears which is accessible via
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.Xr ifconfig 8 .
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.Nm Iface
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node interfaces are named
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.Dv ng0 ,
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.Dv ng1 ,
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etc.
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When a node is shutdown, the corresponding interface is removed
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and the interface name becomes available for reuse by future
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.Nm iface
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nodes; new nodes always take the first unused interface.
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The node itself is assigned the same name as its interface, unless the name
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already exists, in which case the node remains unnamed.
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.Pp
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An
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.Nm iface
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node has a single hook corresponding to each supported protocol.
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Packets transmitted via the interface flow out the corresponding
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protocol-specific hook.
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Similarly, packets received on a hook appear on the interface as
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packets received into the corresponding protocol stack.
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The currently supported protocols are IP, IPv6, ATM, NATM, and NS.
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.Pp
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An
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.Nm iface
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node can be configured as a point-to-point interface or a broadcast interface.
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The configuration can only be changed when the interface is down.
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The default mode is point-to-point.
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.Pp
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.Nm Iface
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nodes support the Berkeley Packet Filter (BPF).
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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 inet6"
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.It Va inet
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Transmission and reception of IP packets.
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.It Va inet6
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Transmission and reception of IPv6 packets.
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.It Va atm
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Transmission and reception of ATM packets.
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.It Va natm
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Transmission and reception of NATM packets.
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.It Va ns
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Transmission and reception of NS packets.
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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_IFACE_GET_IFNAME Pq Ic getifname
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Returns the name of the associated interface as a
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.Dv NUL Ns -terminated
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.Tn ASCII
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string.
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Normally this is the same as the name of the node.
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.It Dv NGM_IFACE_GET_IFINDEX Pq Ic getifindex
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Returns the global index of the associated interface as a 32 bit integer.
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.It Dv NGM_IFACE_POINT2POINT Pq Ic point2point
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Set the interface to point-to-point mode.
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The interface must not currently be up.
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.It Dv NGM_IFACE_BROADCAST Pq Ic broadcast
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Set the interface to broadcast mode.
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The interface must not currently be up.
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.El
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.Sh SHUTDOWN
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This node shuts down upon receipt of a
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.Dv NGM_SHUTDOWN
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control message.
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The associated interface is removed and becomes available
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for use by future
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.Nm iface
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nodes.
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.Pp
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Unlike most other node types, an
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.Nm iface
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node does
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.Em not
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go away when all hooks have been disconnected; rather, and explicit
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.Dv NGM_SHUTDOWN
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control message is required.
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.Sh ALTQ Support
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The
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.Nm
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interface supports ALTQ bandwidth management feature.
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However,
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.Nm
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is a special case, since it is not a physical interface with limited bandwidth.
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One should not turn ALTQ on
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.Nm
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if the latter corresponds to some tunneled connection, e.g.\& PPPoE or PPTP.
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In this case, ALTQ should be configured on the interface that is used to
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transmit the encapsulated packets.
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In case when your graph ends up with some kind of serial line, either
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synchronous or modem, the
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.Nm
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is the right place to turn ALTQ on.
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.Sh Nesting
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.Nm
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supports nesting, a configuration when traffic of one
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.Nm
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interface flows through the other.
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The default maximum allowed nesting level is 2.
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It can be changed at runtime setting
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.Xr sysctl 8
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variable
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.Va net.graph.iface.max_nesting
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to the desired level of nesting.
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.Sh SEE ALSO
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.Xr altq 4 ,
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.Xr bpf 4 ,
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.Xr netgraph 4 ,
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.Xr ng_cisco 4 ,
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.Xr ifconfig 8 ,
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.Xr ngctl 8
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.Xr sysctl
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.Sh HISTORY
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The
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.Nm iface
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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 Archie Cobbs Aq Mt archie@FreeBSD.org
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