1.\" 2.\" Copyright (c) 2001, FreeBSD Inc. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice unmodified, this list of conditions, and the following 10.\" disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man4/ng_etf.4,v 1.3.2.1 2002/04/09 20:17:17 julian Exp $ 28.\" 29.Dd February 28, 2001 30.Dt NG_ETF 4 31.Os 32.Sh NAME 33.Nm ng_etf 34.Nd Ethertype filtering netgraph node type 35.Sh SYNOPSIS 36.In netgraph/etf/ng_etf.h 37.Sh DESCRIPTION 38The 39.Nm etf 40node type multiplexes and filters data between hooks on the basis 41of the ethertype found in an ethernet header, presumed to be in the 42first 14 bytes of the data. 43Incoming Ethernet frames are accepted on the 44.Em downstream 45hook and if the ethertype matches a value which the node has been configured 46to filter, the packet is forwarded out the hook which was identified 47at the time that value was configured. 48If it does not match a configured 49value, it is passed to the 50.Em nomatch 51hook. 52If the 53.Em nomatch 54hook is not connected, the packet is dropped. 55.Pp 56Packets travelling in the other direction (towards the 57.Em downstream 58hook) are also examined and filtered. 59If a packet has an ethertype that matches one of the values configured 60into the node, it must have arrived in on the hook for which that value 61was configured, otherwise it will be discarded. 62Ethertypes of values other 63than those configured by the control messages must have arrived via the 64.Em nomatch 65hook. 66.Sh HOOKS 67This node type supports the following hooks: 68.Bl -tag -width ".Em downstream" 69.It Em downstream 70Typically this hook would be connected to a 71.Xr ng_ether 4 72node, using the 73.Em lower 74hook. 75.It Em nomatch 76Typically this hook would also be connected to an 77.Xr ng_ether 4 78type node using the 79.Em upper 80hook. 81.It Aq Em "any legal name" 82Any other hook name will be accepted and can be used as the match target 83of an ethertype. 84Typically this hook would be attached to 85a protocol handling node that requires and generates packets 86with a particular set of ethertypes. 87.El 88.Sh CONTROL MESSAGES 89This node type supports the generic control messages, plus the following: 90.Bl -tag -width 4n 91.It Dv NGM_ETF_GET_STATUS 92This command returns a 93.Vt "struct ng_etfstat" 94containing node statistics for packet counts. 95.It Dv NGM_ETF_SET_FILTER 96Sets the a new ethertype filter into the node and specifies the hook to and 97from which packets of that type should use. 98The hook and ethertype 99are specified in a structure of type 100.Vt "struct ng_etffilter" : 101.Bd -literal -offset 4n 102struct ng_etffilter { 103 char matchhook[NG_HOOKSIZ]; /* hook name */ 104 u_int16_t ethertype; /* catch these */ 105}; 106.Ed 107.El 108.Sh EXAMPLES 109Using 110.Xr ngctl 8 111it is possible to set a filter in place from the command line 112as follows: 113.Bd -literal -offset 4n 114#!/bin/sh 115ETHER_IF=lnc0 116MATCH1=0x834 117MATCH2=0x835 118cat <<DONE >/tmp/xwert 119# Make a new ethertype filter and attach to the ethernet lower hook. 120# first remove left over bits from last time. 121shutdown ${ETHER_IF}:lower 122mkpeer ${ETHER_IF}: etf lower downstream 123# Give it a name to easily refer to it. 124name ${ETHER_IF}:lower etf 125# Connect the nomatch hook to the upper part of the same interface. 126# All unmatched packets will act as if the filter is not present. 127connect ${ETHER_IF}: etf: upper nomatch 128DONE 129ngctl -f /tmp/xwert 130 131# something to set a hook to catch packets and show them. 132echo "Unrecognised packets:" 133nghook -a etf: newproto & 134# Filter two random ethertypes to that hook. 135ngctl 'msg etf: setfilter { matchhook="newproto" ethertype=${MATCH1} } 136ngctl 'msg etf: setfilter { matchhook="newproto" ethertype=${MATCH2} } 137DONE 138.Ed 139.Sh SHUTDOWN 140This node shuts down upon receipt of a 141.Dv NGM_SHUTDOWN 142control message, or when all hooks have been disconnected. 143.Sh SEE ALSO 144.Xr netgraph 4 , 145.Xr ng_ether 4 , 146.Xr ngctl 8 , 147.Xr nghook 8 148.Sh HISTORY 149The 150.Nm 151node type was implemented in 152.Fx 4.6 . 153.Sh AUTHORS 154.An Julian Elischer Aq Mt julian@FreeBSD.org 155