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 on RFC 2697, 44.It 45Two rate three color marker as described on 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 modes: 76.Bl -tag -width indent 77.It Dv NG_CAR_SINGLE_RATE 78Single rate three color marker as described on RFC 2697. 79Committed burst packets are counted as green, extended burst packets are counted as yellow 80and exceeding packets are counted as red. Committed burst getting refilled with cir speed. 81When it is full, exceeded burst getting refilled. 82.It Dv NG_CAR_DOUBLE_RATE 83Two rate three color marker as described on RFC 2698. 84Committed burst packets are counted as green, peak burst packets are counted as yellow 85and exceeding packets are counted as red. Committed burst getting refilled with cir speed. 86Peak burst getting refilled with pir speed at the same time. 87.It Dv NG_CAR_RED 88Alike to NG_CAR_SINGLE_RATE, but with different understanding of extended burst. 89When normal burst exceeded and extended burst is used, packets are counted red with 90probability equal to part of extended burst consumed. Extended burst getting refilled first. 91When it is full, committed burst getting refilled. This behavior is alike to RED 92active queue management algorithm. 93.Pp 94This algorithm is more polite to the TCP traffic then NG_CAR_SINGLE_RATE. 95.It Dv NG_CAR_SHAPE 96Committed burst packets are counted as green, exceeding packets are delayed 97by queue with RED management and counted as yellow. Packets dropped by queue counted as red. 98Queue parameters are hardcoded: length 99 packets, min_th 8 packets, max_p 100%. 99.Pp 100Traffic shaping is much more polite to the TCP traffic then rate limit on links with 101bandwidth * delay product less then 6-8 TCP segments, but it consumes additional system 102resources for queue processing. 103.El 104.Sh CONTROL MESSAGES 105This node type supports the generic control messages and the following 106specific messages. 107.Bl -tag -width indent 108.It Dv NGM_CAR_SET_CONF Pq Li setconf 109Set node configuration to the specified at 110.Vt "struct ng_car_bulkconf" 111.It Dv NGM_CAR_GET_CONF Pq Li getconf 112Return current node configuration as 113.Vt "struct ng_car_bulkconf" 114.Bd -literal -offset 4n 115struct ng_car_hookconf { 116 u_int64_t cbs; /* Committed burst size (bytes) */ 117 u_int64_t ebs; /* Exceeded/Peak burst size (bytes) */ 118 u_int64_t cir; /* Committed information rate (bytes/s) */ 119 u_int64_t pir; /* Peak information rate (bits/s) */ 120 u_int8_t green_action; /* Action for green packets */ 121 u_int8_t yellow_action; /* Action for yellow packets */ 122 u_int8_t red_action; /* Action for red packets */ 123 u_int8_t mode; /* single/double rate, ... */ 124 u_int8_t opt; /* color-aware or color-blind */ 125}; 126 127struct ng_car_bulkconf { 128 struct ng_car_hookconf upstream; 129 struct ng_car_hookconf downstream; 130}; 131.Ed 132.It Dv NGM_CAR_GET_STATS Pq Li getstats 133Return node statistics as 134.Vt "struct ng_car_bulkstats" 135.Bd -literal -offset 4n 136struct ng_car_hookstats { 137 u_int64_t passed_pkts; 138 u_int64_t droped_pkts; 139 u_int64_t green_pkts; 140 u_int64_t yellow_pkts; 141 u_int64_t red_pkts; 142 u_int64_t errors; 143}; 144 145struct ng_car_bulkstats { 146 struct ng_car_hookstats upstream; 147 struct ng_car_hookstats downstream; 148}; 149.Ed 150.It Dv NGM_CAR_CLR_STATS Pq Li clrstats 151Clear node statistics. 152.It Dv NGM_CAR_GETCLR_STATS Pq Li getclrstats 153Atomicaly return and clear node statistics. 154.El 155.Sh SHUTDOWN 156This node shuts down upon receipt of a 157.Dv NGM_SHUTDOWN 158control message, or when all hooks have been disconnected. 159.Sh SEE ALSO 160.Xr netgraph 4 , 161.Xr ngctl 8 162.Rs 163.%A J. Heinanen 164.%T "A Single Rate Three Color Marker" 165.%O RFC 2697 166.Re 167.Rs 168.%A J. Heinanen 169.%T "A Two Rate Three Color Marker" 170.%O RFC 2698 171.Re 172.Sh AUTHORS 173.An Nuno Antunes Aq nuno.antunes@gmail.com 174.An Alexander Motin Aq mav@alkar.net 175.Sh BUGS 176For this moment only DROP and FORWARD actions are implemented. 177