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 111.Sh CONTROL MESSAGES 112This node type supports the generic control messages and the following 113specific messages. 114.Bl -tag -width indent 115.It Dv NGM_CAR_SET_CONF Pq Li setconf 116Set node configuration to the specified at 117.Vt "struct ng_car_bulkconf" 118.It Dv NGM_CAR_GET_CONF Pq Li getconf 119Return current node configuration as 120.Vt "struct ng_car_bulkconf" 121.Bd -literal 122struct ng_car_hookconf { 123 u_int64_t cbs; /* Committed burst size (bytes) */ 124 u_int64_t ebs; /* Exceeded/Peak burst size (bytes) */ 125 u_int64_t cir; /* Committed information rate (bits/s) */ 126 u_int64_t pir; /* Peak information rate (bits/s) */ 127 u_int8_t green_action; /* Action for green packets */ 128 u_int8_t yellow_action; /* Action for yellow packets */ 129 u_int8_t red_action; /* Action for red packets */ 130 u_int8_t mode; /* single/double rate, ... */ 131 u_int8_t opt; /* color-aware or color-blind */ 132}; 133 134struct ng_car_bulkconf { 135 struct ng_car_hookconf upstream; 136 struct ng_car_hookconf downstream; 137}; 138.Ed 139.It Dv NGM_CAR_GET_STATS Pq Li getstats 140Return node statistics as 141.Vt "struct ng_car_bulkstats" 142.Bd -literal 143struct ng_car_hookstats { 144 u_int64_t passed_pkts; 145 u_int64_t droped_pkts; 146 u_int64_t green_pkts; 147 u_int64_t yellow_pkts; 148 u_int64_t red_pkts; 149 u_int64_t errors; 150}; 151 152struct ng_car_bulkstats { 153 struct ng_car_hookstats upstream; 154 struct ng_car_hookstats downstream; 155}; 156.Ed 157.It Dv NGM_CAR_CLR_STATS Pq Li clrstats 158Clear node statistics. 159.It Dv NGM_CAR_GETCLR_STATS Pq Li getclrstats 160Atomically return and clear node statistics. 161.El 162.Sh SHUTDOWN 163This node shuts down upon receipt of a 164.Dv NGM_SHUTDOWN 165control message, or when all hooks have been disconnected. 166.Sh SEE ALSO 167.Xr netgraph 4 , 168.Xr ngctl 8 169.Rs 170.%A J. Heinanen 171.%T "A Single Rate Three Color Marker" 172.%O RFC 2697 173.Re 174.Rs 175.%A J. Heinanen 176.%T "A Two Rate Three Color Marker" 177.%O RFC 2698 178.Re 179.Sh AUTHORS 180.An Nuno Antunes Aq nuno.antunes@gmail.com 181.An Alexander Motin Aq mav@FreeBSD.org 182.Sh BUGS 183At this moment only DROP and FORWARD actions are implemented. 184