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Diffstat (limited to 'lib/Vyatta/Qos/RandomDetect.pm')
| -rw-r--r-- | lib/Vyatta/Qos/RandomDetect.pm | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/lib/Vyatta/Qos/RandomDetect.pm b/lib/Vyatta/Qos/RandomDetect.pm new file mode 100644 index 0000000..155b669 --- /dev/null +++ b/lib/Vyatta/Qos/RandomDetect.pm @@ -0,0 +1,143 @@ +# Random Detect +# +# This Qos module uses DSMARK and GRED to provide a policy +# similar to Cisco Weighted Random Detect. +# +# See Almesberger, Werner; Hadi Salim, Jamal; Kuznetsov, Alexey +# "Differentiated Services on Linux" +# http://www.almesberger.net/cv/papers/18270721.pdf +# +# **** License **** +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 2 as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# General Public License for more details. +# +# This code was originally developed by Vyatta, Inc. +# Portions created by Vyatta are Copyright (C) 2008 Vyatta, Inc. +# All Rights Reserved. +# **** End License **** + +package Vyatta::Qos::RandomDetect; +use strict; +use warnings; + +require Vyatta::Config; +use Vyatta::Qos::Util qw/getRate getAutoRate getTime/; + +# default values for different precedence levels +my @default_fields = ( + { 'min-threshold' => 9, 'max-threshold' => 18, 'mark-probability' => 1/2 }, + { 'min-threshold' => 10, 'max-threshold' => 18, 'mark-probability' => 5/9 }, + { 'min-threshold' => 11, 'max-threshold' => 18, 'mark-probability' => .1 }, + { 'min-threshold' => 12, 'max-threshold' => 18, 'mark-probability' => 2/3 }, + { 'min-threshold' => 13, 'max-threshold' => 18, 'mark-probability' => .1 }, + { 'min-threshold' => 14, 'max-threshold' => 18, 'mark-probability' => 7/9 }, + { 'min-threshold' => 15, 'max-threshold' => 18, 'mark-probability' => 5/6 }, + { 'min-threshold' => 16, 'max-threshold' => 18, 'mark-probability' => 8/9 }, +); + +# Create a new instance based on config information +sub new { + my ( $that, $config, $name ) = @_; + my $level = $config->setLevel(); + + my $rate = $config->returnValue("bandwidth"); + die "$level bandwidth configuration missing" unless $rate; + my @precedence = getPrecedence( $level ); + + my $self = {}; + my $class = ref($that) || $that; + bless $self, $class; + + $self->{_rate} = $rate; + $self->{_precedence} = \@precedence; + + return $self; +} + +sub getPrecedence { + my ( $level ) = @_; + my $config = new Vyatta::Config; + my @precedence; + + for ( my $i = 0 ; $i <= 7 ; $i++ ) { + my $defaults = $default_fields[$i]; + my %param; + + $config->setLevel("$level precedence $i"); + foreach my $field (keys %$defaults) { + my $val = $config->returnValue($field); + + if ( !defined $val ) { + $param{$field} = $defaults->{$field}; + } elsif ( $field eq 'mark-probability' ) { + $param{$field} = 1 / $val; + } else { + $param{$field} = $val; + } + } + $precedence[$i] = \%param; + } + + return @precedence; +} + +sub commands { + my ( $self, $dev ) = @_; + my $root = 1; + my $precedence = $self->{_precedence}; + my $rate = getAutoRate( $self->{_rate}, $dev ); + + # 1. setup DSMARK to convert DSCP to tc_index + print "qdisc add dev eth0 root handle $root: dsmark indices 1 set_tc_index\n"; + + # 2. use tcindex filter to convert tc_index to precedence + print + "filter add dev $dev parent $root: protocol ip prio 1 tcindex mask 0xe0 shift 5\n"; + + print "qdisc add dev $dev parent $root: gred setup DPs 8 default 7\n"; + + # set VQ parameters + for ( my $i = 0 ; $i <= 7 ; $i++ ) { + my $param = $precedence->[$i]; + my $qmin = $param->{'min-threshold'}; + my $qmax = $param->{'max-threshold'}; + my $prob = $param->{'mark-probability'}; + + print "qdisc change dev $dev parent $root:$i gred"; + printf " limit %dK min %dK max %dK avpkt 1K", 4 * $qmax, $qmin, $qmax; + printf " burst %d bandwidth %d DP %d probability %f\n", + ( 2 * $qmin + $qmax ) / 3, $rate, $i, $prob; + } +} + +# Walk configuration tree and look for changed nodes +# The configuration system should do this but doesn't do it right +sub isChanged { + my ( $self, $name ) = @_; + my $config = new Vyatta::Config; + + $config->setLevel("qos-policy random-detect $name"); + + return 'bandwidth' if ( $config->isChanged('bandwidth') ); + + my %precedenceNodes = $config->listNodeStatus('precedence'); + while ( my ( $pred, $status ) = each %precedenceNodes ) { + return "precedence $pred" if ( $status ne 'static' ); + + my $defaults = $default_fields[0]; + foreach my $attr (keys %$defaults) { + return "precedence $pred $attr" + if ( $config->isChanged("precedence $pred $attr") ); + } + } + + return; # false +} + +1; |