1.\" Copyright (c) 2005 Nuno Antunes <nuno.antunes@gmail.com> 2.\" Copyright (c) 2007 Alexander Motin <mav@FreeBSD.org> 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, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd March 11, 2007 29.Dt NG_CAR 4 30.Os 31.Sh NAME 32.Nm ng_car 33.Nd Commited Access Rate netgraph node type 34.Sh SYNOPSIS 35.In netgraph/ng_car.h 36.Sh DESCRIPTION 37The 38.Nm car 39node type limits traffic flowing through it using: 40.Pp 41.Bl -bullet -compact 42.It 43Single rate three color marker as described in RFC 2697, 44.It 45Two rate three color marker as described in RFC 2698, 46.It 47RED-like rate limit algorithm used by Cisco, 48.It 49Traffic shaping with RED. 50.El 51.Sh HOOKS 52This node type supports the following hooks: 53.Bl -tag -width indent 54.It Va upper 55Hook leading to upper layer protocols. 56.It Va lower 57Hook leading to lower layer protocols. 58.El 59.Pp 60Traffic flowing from 61.Va upper 62to 63.Va lower 64is considered 65.Sy downstream 66traffic. 67Traffic flowing from 68.Va lower 69to 70.Va upper 71is considered 72.Sy upstream 73traffic. 74.Sh MODES OF OPERATION 75Each hook can operate in one of the following modes: 76.Bl -tag -width indent 77.It Dv NG_CAR_SINGLE_RATE 78Single rate three color marker as described in RFC 2697. 79Committed burst packets are counted as green, extended burst packets are 80counted as yellow and exceeding packets are counted as red. 81Committed burst getting refilled with CIR (Committed Information Rate) speed. 82When it is full, exceeded burst getting refilled. 83.It Dv NG_CAR_DOUBLE_RATE 84Two rate three color marker as described in RFC 2698. 85Committed burst packets are counted as green, peak burst packets are counted 86as yellow and exceeding packets are counted as red. 87Committed burst getting refilled with CIR speed. 88Peak burst getting refilled with PIR (Peak Information Rate) speed at the 89same time. 90.It Dv NG_CAR_RED 91Similar to 92.Dv NG_CAR_SINGLE_RATE , 93but with different understanding of extended burst. 94When normal burst exceeded and extended burst is used, packets are counted 95red with probability equal to part of extended burst consumed. 96Extended burst getting refilled first. 97When it is full, committed burst getting refilled. 98This behavior is similar to RED active queue management algorithm. 99.Pp 100This algorithm is more polite to the TCP traffic than NG_CAR_SINGLE_RATE. 101.It Dv NG_CAR_SHAPE 102Committed burst packets are counted as green, exceeding packets are delayed 103by queue with RED management and counted as yellow. 104Packets dropped by queue counted as red. 105Queue parameters are hardcoded: length 99 packets, min_th 8 packets, max_p 100%. 106.Pp 107Traffic shaping is much more polite to the TCP traffic than rate limit on 108links with bandwidth * delay product less than 6-8 TCP segments, but it 109consumes additional system resources for queue processing. 110.El 111By default, all information rates are measured in bits per second and bursts 112are measured in bytes. But when NG_CAR_COUNT_PACKETS option is enabled, 113rates are measured in packets per second and bursts are in packets. 114.Sh CONTROL MESSAGES 115This node type supports the generic control messages and the following 116specific messages. 117.Bl -tag -width indent 118.It Dv NGM_CAR_SET_CONF Pq Li setconf 119Set node configuration to the specified at 120.Vt "struct ng_car_bulkconf" 121.It Dv NGM_CAR_GET_CONF Pq Li getconf 122Return current node configuration as 123.Vt "struct ng_car_bulkconf" 124.Bd -literal 125struct ng_car_hookconf { 126 u_int64_t cbs; /* Committed burst size */ 127 u_int64_t ebs; /* Exceeded/Peak burst size */ 128 u_int64_t cir; /* Committed information rate */ 129 u_int64_t pir; /* Peak information rate */ 130 u_int8_t green_action; /* Action for green packets */ 131 u_int8_t yellow_action; /* Action for yellow packets */ 132 u_int8_t red_action; /* Action for red packets */ 133 u_int8_t mode; /* operation mode */ 134 u_int8_t opt; /* mode options */ 135}; 136 137/* possible actions (..._action) */ 138enum { 139 NG_CAR_ACTION_FORWARD = 1, 140 NG_CAR_ACTION_DROP 141}; 142 143/* operation modes (mode) */ 144enum { 145 NG_CAR_SINGLE_RATE = 0, 146 NG_CAR_DOUBLE_RATE, 147 NG_CAR_RED, 148 NG_CAR_SHAPE 149}; 150 151/* mode options (opt) */ 152#define NG_CAR_COUNT_PACKETS 2 153 154struct ng_car_bulkconf { 155 struct ng_car_hookconf upstream; 156 struct ng_car_hookconf downstream; 157}; 158.Ed 159.It Dv NGM_CAR_GET_STATS Pq Li getstats 160Return node statistics as 161.Vt "struct ng_car_bulkstats" 162.Bd -literal 163struct ng_car_hookstats { 164 u_int64_t passed_pkts; 165 u_int64_t droped_pkts; 166 u_int64_t green_pkts; 167 u_int64_t yellow_pkts; 168 u_int64_t red_pkts; 169 u_int64_t errors; 170}; 171 172struct ng_car_bulkstats { 173 struct ng_car_hookstats upstream; 174 struct ng_car_hookstats downstream; 175}; 176.Ed 177.It Dv NGM_CAR_CLR_STATS Pq Li clrstats 178Clear node statistics. 179.It Dv NGM_CAR_GETCLR_STATS Pq Li getclrstats 180Atomically return and clear node statistics. 181.El 182.Sh SHUTDOWN 183This node shuts down upon receipt of a 184.Dv NGM_SHUTDOWN 185control message, or when all hooks have been disconnected. 186.Sh EXAMPLES 187Limit outgoing data rate over fxp0 Ethernet interface to 20Mbit/s 188and incoming packet rate to 5000pps. 189.Bd -literal -offset indent 190/usr/sbin/ngctl -f- <<-SEQ 191 mkpeer fxp0: car lower lower 192 name fxp0:lower fxp0_car 193 connect fxp0: fxp0_car: upper upper 194 msg fxp0_car: setconf { downstream={ cir=20000000 cbs=2500000 ebs=2500000 greenAction=1 yellowAction=1 redAction=2 mode=2 } upstream={ cir=5000 cbs=100 ebs=100 greenAction=1 yellowAction=1 redAction=2 mode=2 opt=2 } } 195SEQ 196.Ed 197.Sh SEE ALSO 198.Xr netgraph 4 , 199.Xr ngctl 8 200.Rs 201.%A J. Heinanen 202.%T "A Single Rate Three Color Marker" 203.%O RFC 2697 204.Re 205.Rs 206.%A J. Heinanen 207.%T "A Two Rate Three Color Marker" 208.%O RFC 2698 209.Re 210.Sh AUTHORS 211.An Nuno Antunes Aq nuno.antunes@gmail.com 212.An Alexander Motin Aq mav@FreeBSD.org 213.Sh BUGS 214At this moment only DROP and FORWARD actions are implemented. 215