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106 KiB
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2428 lines
106 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<article>
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<!--$Id$-->
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<articleinfo>
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<title>Complex Traffic Shaping/Control</title>
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<authorgroup>
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<author>
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<firstname>Tom</firstname>
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<surname>Eastep</surname>
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</author>
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<author>
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<firstname>Arne</firstname>
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<surname>Bernin</surname>
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</author>
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</authorgroup>
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<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
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<copyright>
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<year>2001-2013</year>
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<holder>Thomas M. Eastep</holder>
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</copyright>
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<copyright>
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<year>2005</year>
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<holder>Arne Bernin & Thomas M. Eastep</holder>
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</copyright>
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<legalnotice>
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<para>Permission is granted to copy, distribute and/or modify this
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document under the terms of the GNU Free Documentation License, Version
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1.2 or any later version published by the Free Software Foundation; with
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no Invariant Sections, with no Front-Cover, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled
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<quote><ulink url="GnuCopyright.htm">GNU Free Documentation
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License</ulink></quote>.</para>
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</legalnotice>
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</articleinfo>
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<important>
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<para>Traffic shaping is complex and the Shorewall community is not well
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equipped to answer traffic shaping questions. So if you are the type of
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person who needs "insert tab A into slot B" instructions for everything
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that you do, then please don't try to implement traffic shaping using
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Shorewall. You will just frustrate yourself and we won't be able to help
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you.</para>
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</important>
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<warning>
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<para>Said another way, reading just Shorewall documentation is not going
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to give you enough background to use this material.</para>
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<para>At a minimum, you will need to refer to at least the following
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additional information:</para>
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<itemizedlist>
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<listitem>
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<para><emphasis>The LARTC HOWTO</emphasis>: <ulink
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url="http://www.lartc.org">http://www.lartc.org</ulink></para>
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</listitem>
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<listitem>
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<para>T<emphasis>he HTB User's Guide</emphasis>: <ulink
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url="http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm">http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm</ulink></para>
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</listitem>
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<listitem>
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<para><emphasis>HFSC Scheduling with Linux</emphasis>: <ulink
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url="http://linux-ip.net/articles/hfsc.en/">http://linux-ip.net/articles/hfsc.en/</ulink></para>
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</listitem>
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<listitem>
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<para>Some of the documents listed at <ulink
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url="http://www.netfilter.org/documentation/index.html#documentation-howto">http://www.netfilter.org/documentation/index.html#documentation-howto</ulink>.
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The tutorial by Oskar Andreasson is particularly good.</para>
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</listitem>
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<listitem>
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<para>The output of <command>man iptables</command></para>
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</listitem>
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</itemizedlist>
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</warning>
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<section id="Intro">
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<title>Introduction</title>
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<para>Beginning with Shorewall 4.4.6, Shorewall includes two separate
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implementations of traffic shaping. This document describes the original
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implementation which is complex and difficult to configure. A much simpler
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version is described in <ulink role="bold"
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url="simple_traffic_shaping.html">Simple Traffic Shaping/Control</ulink>
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and is highly recommended unless you really need to delay certain traffic
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passing through your firewall.</para>
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<para>Shorewall has builtin support for traffic shaping and control. This
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support does not cover all options available (and especially all
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algorithms that can be used to queue traffic) in the Linux kernel but it
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should fit most needs. If you are using your own script for traffic
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control and you still want to use it in the future, you will find
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information on how to do this, <link linkend="owntcstart">later in this
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document</link>. But for this to work, you will also need to enable
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traffic shaping in the kernel and Shorewall as covered by the next
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sections.</para>
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</section>
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<section id="LinuxTC">
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<title>Linux traffic shaping and control</title>
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<para>This section gives a brief introduction of how controlling traffic
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with the Linux kernel works. Although this might be enough for configuring
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it in the Shorewall configuration files, we strongly recommend that you
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take a deeper look into the <ulink url="http://lartc.org/howto/">Linux
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Advanced Routing and Shaping HOWTO</ulink>. At the time of writing this,
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the current version is 1.0.0.</para>
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<para>Since kernel 2.2, Linux has extensive support for controlling
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traffic. You can define different algorithms that are used to queue the
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traffic before it leaves an interface. The standard one is called pfifo
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and is (as the name suggests) of the type First In First out. This means,
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that it does not shape anything, if you have a connection that eats up all
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your bandwidth, this queuing algorithm will not stop it from doing
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so.</para>
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<para>For Shorewall traffic shaping we use three algorithms: HTB
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(Hierarchical Token Bucket), HFSC (Hierarchical Fair Service Curves) and
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SFQ (Stochastic Fairness Queuing). SFQ is easy to explain: it just tries
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to track your connections (tcp or udp streams) and balances the traffic
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between them. This normally works well. HTB and HFSC allow you to define a
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set of classes, and you can put the traffic you want into these classes.
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You can define minimum and maximum bandwidth settings for those classes
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and order them hierarchically (the less prioritized classes only get
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bandwidth if the more important have what they need). Additionally, HFSC
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allows you to specify the maximum queuing delay that a packet may
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experience. Shorewall builtin traffic shaping allows you to define these
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classes (and their bandwidth limits), and it uses SFQ inside these classes
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to make sure, that different data streams are handled equally. If SFQ's
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default notion of a 'stream' doesn't work well for you, you can change it
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using the <emphasis role="bold">flow</emphasis> option described <link
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linkend="tcclasses">below</link>.</para>
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<para>You can shape incoming traffic through use of an
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<firstterm>Intermediate Functional Block</firstterm> (IFB) device. <link
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linkend="IFB">See below</link>. <emphasis role="bold">But beware: using an
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IFB can result in queues building up both at your ISPs router and at your
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own.</emphasis></para>
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<para>You shape and control outgoing traffic by assigning the traffic to
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<firstterm>classes</firstterm>. Each class is associated with exactly one
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network interface and has a number of attributes:</para>
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<orderedlist>
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<listitem>
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<para>PRIORITY - Used to give preference to one class over another
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when selecting a packet to send. The priority is a numeric value with
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1 being the highest priority, 2 being the next highest, and so
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on.</para>
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</listitem>
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<listitem>
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<para>RATE - The minimum bandwidth this class should get, when the
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traffic load rises. Classes with a higher priority (lower PRIORITY
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value) are served even if there are others that have a guaranteed
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bandwidth but have a lower priority (higher PRIORITY value).</para>
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</listitem>
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<listitem>
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<para>CEIL - The maximum bandwidth the class is allowed to use when
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the link is idle.</para>
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</listitem>
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<listitem>
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<para>MARK - Netfilter has a facility for
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<firstterm>marking</firstterm> packets. Packet marks have a numeric
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value which is limited in Shorewall to the values 1-255 (1-16383 if
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you set WIDE_TC_MARKS=Yes in <ulink
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url="manpages/shorewall.conf.html">shorewall.conf</ulink> (5) ). You
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assign packet marks to different types of traffic using entries in the
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<filename>/etc/shorewall/tcrules</filename> file.</para>
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<note>
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<para>In Shorewall 4.4.26, WIDE_TC_MARKS was superseded by TC_BITS
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which specifies the width in bits of the traffic shaping mark field.
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The default is based on the setting of WIDE_TC_MARKS so as to
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provide upward compatibility. See the <ulink
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url="PacketMarking.html#Values">Packet Marking using
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/etc/shorewall/tcrules</ulink> article.</para>
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</note>
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</listitem>
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</orderedlist>
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<para>One class for each interface must be designated as the
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<firstterm>default class</firstterm>. This is the class to which unmarked
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traffic (packets to which you have not assigned a mark value in
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<filename>/etc/shorewall/tcrules</filename>) is assigned.</para>
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<para>Netfilter also supports a mark value on each connection. You can
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assign connection mark values in
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<filename>/etc/shorewall/tcrules</filename>, you can copy the current
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packet's mark to the connection mark (SAVE), or you can copy the
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connection mark value to the current packet's mark (RESTORE). For more
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information, see<ulink url="PacketMarking.html"> this
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article</ulink>.</para>
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</section>
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<section id="Kernel">
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<title>Linux Kernel Configuration</title>
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<para>You will need at least kernel 2.4.18 for this to work, please take a
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look at the following screenshot for what settings you need to enable. For
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builtin support, you need the HTB scheduler, the Ingress scheduler, the
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PRIO pseudoscheduler and SFQ queue. The other scheduler or queue
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algorithms are not needed.</para>
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<para>This screen shot shows how I configured QoS in a 2.6.16
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Kernel:</para>
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<graphic align="center" fileref="images/traffic_shaping2.6.png" />
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<para>And here's my recommendation for a 2.6.21 kernel:<graphic
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align="center" fileref="images/traffic_shaping2.6.21.png" /></para>
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</section>
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<section id="Shorewall">
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<title>Enable TC support in Shorewall</title>
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<para>You need this support whether you use the builtin support or whether
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you provide your own tcstart script.</para>
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<para>To enable the builtin traffic shaping and control in Shorewall, you
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have to do the following:</para>
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<itemizedlist>
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<listitem>
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<para>Set <emphasis role="bold">TC_ENABLED</emphasis> to "<emphasis
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role="bold">Internal</emphasis>" in /etc/shorewall/shorewall.conf.
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Setting <emphasis role="bold">TC_ENABLED=Yes</emphasis> causes
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Shorewall to look for an external tcstart file (See <link
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linkend="tcstart">a later section</link> for details).</para>
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</listitem>
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<listitem>
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<para>Setting <emphasis role="bold">CLEAR_TC</emphasis> parameter in
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/etc/shorewall/shorewall.conf to <emphasis role="bold">Yes</emphasis>
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will clear the traffic shaping configuration during Shorewall
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[re]start and Shorewall stop. This is normally what you want when
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using the builtin support (and also if you use your own tcstart
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script)</para>
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</listitem>
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<listitem>
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<para>The other steps that follow depend on whether you use your own
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script or the builtin solution. They will be explained in the
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following sections.</para>
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</listitem>
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</itemizedlist>
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</section>
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<section id="Builtin">
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<title>Using builtin traffic shaping/control</title>
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<para>Shorewall's builtin traffic shaping feature provides a thin layer on
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top of the ingress qdesc, HTB and SFQ. That translation layer allows you
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to:</para>
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<itemizedlist>
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<listitem>
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<para>Define HTB and/or HFSC classes using Shorewall-style
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column-oriented configuration files.</para>
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</listitem>
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<listitem>
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<para>Integrate the reloading of your traffic shaping configuration
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with the reloading of your packet-filtering and marking
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configuration.</para>
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</listitem>
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<listitem>
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<para>Assign traffic to HTB or HFSC classes by TOS value.</para>
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</listitem>
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<listitem>
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<para>Assign outgoing TCP ACK packets to an HTB or HFSC class.</para>
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</listitem>
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<listitem>
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<para>Assign traffic to HTB and/or HFSC classes based on packet mark
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value or based on packet contents.</para>
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</listitem>
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</itemizedlist>
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<para>Those few features are really all that builtin traffic
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shaping/control provides; consequently, you need to understand HTB and/or
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HFSC and Linux traffic shaping as well as Netfilter packet marking in
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order to use the facility. Again, please see the links at top of this
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article.</para>
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<para>For defining bandwidths (for either devices or classes) please use
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kbit or kbps (for Kilobytes per second) and make sure there is <emphasis
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role="bold">NO</emphasis> space between the number and the unit (it is
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100kbit <emphasis role="bold">not</emphasis> 100 kbit). Using mbit, mbps
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or a raw number (which means bytes) could be used, but note that only
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integer numbers are supported (0.5 is <emphasis role="bold">not
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valid</emphasis>).</para>
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<para><emphasis role="bold">To properly configure the settings for your
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devices you need to find out the real up- and downstream rates you
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have</emphasis>. This is especially the case, if you are using a DSL
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connection or one of another type that do not have a guaranteed bandwidth.
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Don't trust the values your provider tells you for this; especially
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measuring the real download speed is important! There are several online
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tools that help you find out; search for "dsl speed test" on google (For
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Germany you can use <ulink
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url="http://www.speedcheck.arcor.de/cgi-bin/speedcheck.cgi">arcor speed
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check</ulink>). Be sure to choose a test site located near you.</para>
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<section id="tcdevices">
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<title>/etc/shorewall/tcdevices</title>
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<para>This file allows you to define the incoming and outgoing bandwidth
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for the devices you want traffic shaping to be enabled. That means, if
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you want to use traffic shaping for a device, you have to define it
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here. For additional information, see <ulink
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url="manpages/shorewall-tcdevices.html">shorewall-tcdevices</ulink>
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(5).</para>
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<para>Columns in the file are as follows:</para>
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<itemizedlist>
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<listitem>
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<para>INTERFACE - Name of interface. Each interface may be listed
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only once in this file. You may NOT specify the name of an alias
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(e.g., eth0:0) here; see <ulink url="FAQ.htm#faq18">FAQ #18</ulink>.
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You man NOT specify wildcards here, e.g. if you have multiple ppp
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interfaces, you need to put them all in here! Shorewall will
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determine if the device exists and will only configure the device if
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it does exist. If it doesn't exist or it is DOWN, the following
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warning is issued:</para>
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<para><emphasis role="bold">WARNING: Device <device name> is
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not in the UP state -- traffic-shaping configuration
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skipped</emphasis></para>
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<para>Shorewall assigns a sequential <firstterm>interface
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number</firstterm> to each interface (the first entry in
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<filename>/etc/shorewall/tcdevices</filename> is interface 1, the
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second is interface 2 and so on) You can also explicitly specify the
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interface number by prefixing the interface name with the number and
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a colon (":"). Example: 1:eth0.</para>
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<warning>
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<para>Device numbers are expressed in hexidecimal. So the device
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following 9 is A, not 10.</para>
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</warning>
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</listitem>
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<listitem>
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<para>IN-BANDWIDTH - The incoming Bandwidth of that interface.
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Please note that when you use this column, you are not traffic
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shaping incoming traffic, as the traffic is already received before
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you could do so. This Column allows you to define the maximum
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traffic allowed for this interface in total, if the rate is
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exceeded, the excess packets are dropped. You want this mainly if
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you have a DSL or Cable Connection to avoid queuing at your
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providers side. If you don't want any traffic to be dropped set this
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to a value faster than your interface maximum rate (or to 0
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(zero).</para>
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<para>To determine the optimum value for this setting, we recommend
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that you start by setting it significantly below your measured
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download bandwidth (20% or so). While downloading, measure the
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<emphasis>ping</emphasis> response time from the firewall to the
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upstream router as you gradually increase the setting.The optimal
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setting is at the point beyond which the <emphasis>ping</emphasis>
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time increases sharply as you increase the setting.</para>
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<note>
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<para>For fast lines, the actually download speed may be well
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below what you specify here. If you have this problem, then follow
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the bandwidth with a ":" and a <firstterm>burst</firstterm> size.
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The default burst is 10kb, but on my 50mbit line, I specify 200kb.
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(50mbit:200kb).</para>
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</note>
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</listitem>
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<listitem>
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<para>OUT-BANDWIDTH - Specify the outgoing bandwidth of that
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interface. This is the maximum speed your connection can handle. It
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is also the speed you can refer as "full" if you define the tc
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classes. Outgoing traffic above this rate will be dropped.</para>
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</listitem>
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<listitem>
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<para>OPTIONS — A comma-separated list of options from the following
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list:</para>
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<variablelist>
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<varlistentry>
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<term><emphasis role="bold">classify</emphasis></term>
|
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|
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<listitem>
|
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<para>If specified, classification of traffic into the various
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classes is done by CLASSIFY entries in
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<filename>/etc/shorewall/tcrules</filename> or by entries in
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<filename>/etc/shorewall/tcfilters</filename>. No MARK value
|
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will be associated with classes on this interface.</para>
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</listitem>
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</varlistentry>
|
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<varlistentry>
|
|
<term><emphasis role="bold">hfsc</emphasis></term>
|
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|
|
<listitem>
|
|
<para>Shorewall normally uses the <firstterm>Hierarchical
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Token Bucket</firstterm> (HTB) queuing discipline. When
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<option>hfsc</option> is specified, the
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<firstterm>Hierarchical Fair Service Curves</firstterm> (HFSC)
|
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discipline is used instead.</para>
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</listitem>
|
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</varlistentry>
|
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|
|
<varlistentry>
|
|
<term><emphasis role="bold">linklayer</emphasis></term>
|
|
|
|
<listitem>
|
|
<para>Added in Shorewall 4.5.6. Type of link (ethernet, atm,
|
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adsl). When specified, causes scheduler packet size
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manipulation as described in tc-stab (8). When this option is
|
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given, the following options may also be given after
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it:</para>
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<variablelist>
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|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">mtu</emphasis>=<replaceable>mtu</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>The device MTU; default 2048 (will be rounded up
|
|
to a power of two)</para>
|
|
</listitem>
|
|
</varlistentry>
|
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|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">mpu</emphasis>=<replaceable>mpubytes</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>Minimum packet size used in calculations. Smaller
|
|
packets will be rounded up to this size</para>
|
|
</listitem>
|
|
</varlistentry>
|
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|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">tsize</emphasis>=<replaceable>tablesize</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>Size table entries; default is 512</para>
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|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><emphasis
|
|
role="bold">overhead</emphasis>=<replaceable>overheadbytes</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>Number of overhead bytes per packet</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>REDIRECTED INTERFACES — Entries are appropriate in this column
|
|
only if the device in the INTERFACE column names a <link
|
|
linkend="IFB">Intermediate Functional Block (IFB)</link>. It lists
|
|
the physical interfaces that will have their input shaped using
|
|
classes defined on the IFB. Neither the IFB nor any of the
|
|
interfaces listed in this column may have an IN-BANDWIDTH specified.
|
|
You may specify zero (0) or a dash ("-:) in the IN-BANDWIDTH
|
|
column.</para>
|
|
|
|
<para>IFB devices automatically get the <emphasis
|
|
role="bold">classify</emphasis> option.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<example id="Example0">
|
|
<title></title>
|
|
|
|
<para>Suppose you are using PPP over Ethernet (DSL) and ppp0 is the
|
|
interface for this. The device has an outgoing bandwidth of 500kbit
|
|
and an incoming bandwidth of 6000kbit</para>
|
|
|
|
<programlisting>#INTERFACE IN-BANDWITH OUT-BANDWIDTH
|
|
ppp0 6000kbit 500kbit</programlisting>
|
|
</example>
|
|
</section>
|
|
|
|
<section id="tcclasses">
|
|
<title>/etc/shorewall/tcclasses</title>
|
|
|
|
<para>This file allows you to define the actual classes that are used to
|
|
split the outgoing traffic. For additional information, see <ulink
|
|
url="manpages/shorewall-tcclasses.html">shorewall-tcclasses</ulink>
|
|
(5).</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>INTERFACE - Name of interface. Users may also specify the
|
|
interface number. Must match the name (or number) of an interface
|
|
with an entry in <filename>/etc/shorewall/tcdevices</filename>. If
|
|
the interface has the <emphasis role="bold">classify</emphasis>
|
|
option in <filename>/etc/shorewall/tcdevices</filename>, then the
|
|
interface name or number must be followed by a colon and a
|
|
<firstterm>class number</firstterm>. Examples: eth0:1, 4:9. Class
|
|
numbers must be unique for a given interface. Normally, all classes
|
|
defined here are sub-classes of a root class that is implicitly
|
|
defined from the entry in <ulink
|
|
url="shorewall-tcdevices.html">shorewall-tcdevices</ulink>(5). You
|
|
can establish a class hierarchy by specifying a
|
|
<emphasis>parent</emphasis> class (e.g.,
|
|
<emphasis>interface</emphasis>:<emphasis>parent-class</emphasis>:<emphasis>class</emphasis>)
|
|
-- the number of a class that you have previously defined. The
|
|
sub-class may borrow unused bandwidth from its parent.</para>
|
|
|
|
<warning>
|
|
<para>Class numbers are expressed in hexidecimal. So the class
|
|
following class 9 is A, not 10.</para>
|
|
</warning>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>MARK - The mark value which is an integer in the range 1-255
|
|
(1-16383 if you set WIDE_TC_MARKS=Yes or set TC_BITS=14 in <ulink
|
|
url="manpages/shorewall.conf.html">shorewall.conf</ulink> (5) ). You
|
|
define these marks in the tcrules file, marking the traffic you want
|
|
to go into the queuing classes defined in here. You can use the same
|
|
marks for different Interfaces. You must specify "-' in this column
|
|
if the device specified in the INTERFACE column has the <emphasis
|
|
role="bold">classify</emphasis> option in
|
|
<filename>/etc/shorewall/tcdevices</filename>.</para>
|
|
|
|
<note>
|
|
<para>In Shorewall 4.5.0, WIDE_TC_MARKS was superseded by TC_BITS
|
|
which specifies the width in bits of the traffic shaping mark
|
|
field. The default is based on the setting of WIDE_TC_MARKS so as
|
|
to provide upward compatibility.</para>
|
|
</note>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>RATE - The minimum bandwidth this class should get, when the
|
|
traffic load rises. Please note that first the classes which equal
|
|
or a lesser priority value are served even if there are others that
|
|
have a guaranteed bandwidth but a lower priority. <emphasis
|
|
role="bold">If the sum of the RATEs for all classes assigned to an
|
|
INTERFACE exceed that interfaces's OUT-BANDWIDTH, then the
|
|
OUT-BANDWIDTH limit will not be honored.</emphasis></para>
|
|
|
|
<para>When using HFSC, this column may contain 1, 2 or 3 pieces of
|
|
information separated by colons (":"). In addition to the minimum
|
|
bandwidth, leaf classes may specify realtime criteria: DMAX (maximum
|
|
delay in milliseconds) and optionally UMAX (the largest packet
|
|
expected in the class). See <link linkend="HFSC">below</link> for
|
|
details.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>CEIL - The maximum bandwidth this class is allowed to use when
|
|
the link is idle. Useful if you have traffic which can get full
|
|
speed when more important services (e.g. interactive like ssh) are
|
|
not used. You can use the value "full" in here for setting the
|
|
maximum bandwidth to the defined output bandwidth of that
|
|
interface.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>PRIORITY - you have to define a priority for the class.
|
|
packets in a class with a higher priority (=lesser value) are
|
|
handled before less prioritized ones. You can just define the mark
|
|
value here also, if you are increasing the mark values with lesser
|
|
priority.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>OPTIONS - A comma-separated list of options including the
|
|
following:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>default - this is the default class for that interface
|
|
where all traffic should go, that is not classified
|
|
otherwise.</para>
|
|
|
|
<note>
|
|
<para>defining default for exactly <emphasis
|
|
role="bold">one</emphasis> class per interface is
|
|
mandatory!</para>
|
|
</note>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>tos-<tosname> - this lets you define a filter for
|
|
the given <tosname> which lets you define a value of the
|
|
Type Of Service bits in the ip package which causes the package
|
|
to go in this class. Please note, that this filter overrides all
|
|
mark settings, so if you define a tos filter for a class all
|
|
traffic having that mark will go in it regardless of the mark on
|
|
the package. You can use the following for this option:
|
|
tos-minimize-delay (16) tos-maximize-throughput (8)
|
|
tos-maximize-reliability (4) tos-minimize-cost (2)
|
|
tos-normal-service (0)</para>
|
|
|
|
<note>
|
|
<para>Each of this options is only valid for <emphasis
|
|
role="bold">one</emphasis> class per interface.</para>
|
|
</note>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>tcp-ack - if defined causes an tc filter to be created
|
|
that puts all tcp ack packets on that interface that have an
|
|
size of <=64 Bytes to go in this class. This is useful for
|
|
speeding up downloads. Please note that the size of the ack
|
|
packets is limited to 64 bytes as some applications (p2p for
|
|
example) use to make every package an ack package which would
|
|
cause them all into here. We want only packets WITHOUT payload
|
|
to match, so the size limit. Bigger packets just take their
|
|
normal way into the classes.</para>
|
|
|
|
<note>
|
|
<para>This option is only valid for <emphasis
|
|
role="bold">class</emphasis> per interface.</para>
|
|
</note>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>occurs=<emphasis>number</emphasis> - Typically used with
|
|
an IPMARK entry in tcrules. Causes the rule to be replicated for
|
|
a total of <emphasis>number</emphasis> rules. Each rule has a
|
|
successively class number and mark value.</para>
|
|
|
|
<para>When 'occurs' is used:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>The associated device may not have the 'classify'
|
|
option.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class may not be the default class.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class may not have any 'tos=' options (including
|
|
'tcp-ack').</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class should not specify a MARK value. If one is
|
|
specified, it will be ignored with a warning message.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The 'RATE' and 'CEIL' parameters apply to each instance of
|
|
the class. So the total RATE represented by an entry with
|
|
'occurs' will be the listed RATE multiplied by
|
|
<emphasis>number</emphasis>. For additional information, see
|
|
<ulink url="manpages/shorewall-tcrules.html">tcrules</ulink>
|
|
(5).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>flow=<emphasis>keys</emphasis> - Shorewall attaches an SFQ
|
|
queuing discipline to each leaf HTB and HFSC class. SFQ ensures
|
|
that each <firstterm>flow</firstterm> gets equal access to the
|
|
interface. The default definition of a flow corresponds roughly
|
|
to a Netfilter connection. So if one internal system is running
|
|
BitTorrent, for example, it can have lots of 'flows' and can
|
|
thus take up a larger share of the bandwidth than a system
|
|
having only a single active connection. The
|
|
<option>flow</option> classifier (module cls_flow) works around
|
|
this by letting you define what a 'flow' is. The clasifier must
|
|
be used carefully or it can block off all traffic on an
|
|
interface! The flow option can be specified for an HTB or HFSC
|
|
leaf class (one that has no sub-classes). We recommend that you
|
|
use the following:</para>
|
|
|
|
<simplelist>
|
|
<member>Shaping internet-bound traffic: <emphasis
|
|
role="bold">flow=nfct-src</emphasis></member>
|
|
|
|
<member>Shaping traffic bound for your local net: <emphasis
|
|
role="bold">flow=dst</emphasis></member>
|
|
</simplelist>
|
|
|
|
<para>These will cause a 'flow' to consists of the traffic
|
|
to/from each internal system.</para>
|
|
|
|
<para>When more than one key is give, they must be enclosed in
|
|
parenthesis and separated by commas.</para>
|
|
|
|
<para>To see a list of the possible flow keys, run this
|
|
command:</para>
|
|
|
|
<blockquote>
|
|
<para><command>tc filter add flow help</command></para>
|
|
</blockquote>
|
|
|
|
<para>Those that begin with "nfct-" are Netfilter connection
|
|
tracking fields. As shown above, we recommend flow=nfct-src;
|
|
that means that we want to use the source IP address
|
|
<emphasis>before SNAT</emphasis> as the key.</para>
|
|
|
|
<note>
|
|
<para>Shorewall cannot determine ahead of time if the flow
|
|
classifier is available in your kernel (especially if it was
|
|
built into the kernel as opposed to being loaded as a module).
|
|
Consequently, you should check ahead of time to ensure that
|
|
both your kernel and 'tc' utility support the feature.</para>
|
|
|
|
<para>You can test the 'tc' utility by typing (as
|
|
root):</para>
|
|
|
|
<blockquote>
|
|
<para><command>tc filter add flow help</command></para>
|
|
</blockquote>
|
|
|
|
<para>If flow is supported, you will see:</para>
|
|
|
|
<programlisting> Usage: ... flow ...
|
|
|
|
[mapping mode]: map key KEY [ OPS ] ...
|
|
[hashing mode]: hash keys KEY-LIST ...
|
|
|
|
...</programlisting>
|
|
|
|
<para>If 'flow' is not supported, you will see:</para>
|
|
|
|
<programlisting> Unknown filter "flow", hence option "help" is unparsable</programlisting>
|
|
|
|
<para>If your kernel supports module autoloading, just type
|
|
(as root):</para>
|
|
|
|
<blockquote>
|
|
<para><command>modprobe cls_flow</command></para>
|
|
</blockquote>
|
|
|
|
<para>If 'flow' is supported, no output is produced;
|
|
otherwise, you will see:</para>
|
|
|
|
<programlisting> FATAL: Module cls_flow not found.</programlisting>
|
|
|
|
<para>If your kernel is not modularized or does not support
|
|
module autoloading, look at your kernel configuration (either
|
|
<filename>/proc/config.gz</filename> or the
|
|
<filename>.config</filename> file in <filename
|
|
class="directory">/lib/modules/<kernel-version>/build/</filename></para>
|
|
|
|
<para>If 'flow' is supported, you will see: NET_CLS_FLOW=m or
|
|
NET_CLS_FLOW=y.</para>
|
|
|
|
<para>For modularized kernels, Shorewall will attempt to load
|
|
<filename>/lib/modules/<kernel-version>/net/sched/cls_flow.ko</filename>
|
|
by default.</para>
|
|
</note>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>pfifo - When specified for a leaf class, the pfifo queing
|
|
discipline is applied to the class rather than the sfq queuing
|
|
discipline.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>limit=<emphasis>number</emphasis> - Added in Shorewall
|
|
4.4.3. When specified for a leaf class, specifies the maximum
|
|
number of packets that may be queued within the class. The
|
|
<emphasis>number</emphasis> must be > 2 and less than 128. If
|
|
not specified, the value 127 is assumed</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>red=(<replaceable>redoption</replaceable>,...) - Added in
|
|
Shorewall 4.5.6. When specified on a leaf class, causes the
|
|
class to use the red queuing discipline rather than SFQ. See
|
|
tc-red (8) for additional information.</para>
|
|
|
|
<para>See <ulink
|
|
url="manpages/shorewall-tcdevices.html">shorewall-tcdevices</ulink>
|
|
(5) for a description of the allowable
|
|
<replaceable>redoptions</replaceable>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>fq_codel[=(<replaceable>codeloption</replaceable>,...)] -
|
|
Added in Shorewall 4.5.12. When specified on a leaf class,
|
|
causes the class to use the FQ CODEL (<firstterm>Fair-queuing
|
|
Controlled-delay</firstterm>) queuing discipline rather than
|
|
SFQ. See tc-fq_codel (8) for additional information.</para>
|
|
|
|
<para>See <ulink
|
|
url="manpages/shorewall-tcdevices.html">shorewall-tcdevices</ulink>
|
|
(5) for a description of the allowable
|
|
<replaceable>codloptions</replaceable>.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</section>
|
|
|
|
<section id="tcrules">
|
|
<title>/etc/shorewall/tcrules</title>
|
|
|
|
<important>
|
|
<para>Unlike rules in the <ulink
|
|
url="manpages/shorewall-rules.html">shorewall-rules</ulink>(5) file,
|
|
evaluation of rules in this file will continue after a match. So the
|
|
final mark for each packet will be the one assigned by the LAST tcrule
|
|
that matches.</para>
|
|
|
|
<para>Also unlike rules in the <ulink
|
|
url="manpages/shorewall-rules.html">shorewall-rules</ulink>(5) file,
|
|
the tcrules file is not stateful. So every packet that goes into, out
|
|
of or through your firewall is subject to entries in the tcrules
|
|
file.</para>
|
|
|
|
<para>Because tcrules are not stateful, it is necessary to understand
|
|
basic IP socket operation. Here is an edited excerpt from a post on
|
|
the Shorewall Users list:<blockquote>
|
|
<para>For the purposes of this discussion, the world is separated
|
|
into clients and servers. Servers provide services to
|
|
clients.</para>
|
|
|
|
<para>When a server starts, it creates a socket and
|
|
<emphasis>binds</emphasis> the socket to an
|
|
<emphasis>address</emphasis>. For AF_INET (IPv4) and AF_INET6
|
|
(IPv6) sockets, that address is an ordered triple consisting of an
|
|
IPv4 or IPv6 address, a protocol, and possibly a port number. Port
|
|
numbers are only used when the protocol is TCP, UDP, SCTP or DCCP.
|
|
The protocol and port number used by a server are typically
|
|
well-known so that clients will be able to connect to it or send
|
|
datagrams to it. So SSH servers bind to TCP port 22, SMTP servers
|
|
bind to TCP port 25, etc. We will call this port the SERVER
|
|
PORT.</para>
|
|
|
|
<para>When a client want to use the service provided by a server,
|
|
it also creates a socket and, like the server's socket, the
|
|
client's socket must be bound to an address. But in the case of
|
|
the client, the socket is usually given an automatic address
|
|
binding. For AF_INET and AF_INET6 sockets. the IP address is the
|
|
IP address of the client system (loose generalization) and the
|
|
port number is selected from a <firstterm>local port
|
|
range</firstterm>. On Linux systems, the local port range can be
|
|
seen by <command>cat
|
|
/proc/sys/net/ipv4/ip_local_port_range</command>. So it is not
|
|
possible in advance to determine what port the client will be
|
|
using. Whatever it is, we'll call it the CLIENT PORT.</para>
|
|
|
|
<para>Now: <blockquote>
|
|
<para>Packets sent from the client to the server will
|
|
have:<blockquote>
|
|
<para>SOURCE PORT = CLIENT PORT</para>
|
|
|
|
<para>DEST PORT = SERVER PORT</para>
|
|
</blockquote></para>
|
|
|
|
<para>Packets sent from the server to the client will have:
|
|
<blockquote>
|
|
<para>SOURCE PORT = SERVER PORT</para>
|
|
|
|
<para>DEST PORT = CLIENT PORT</para>
|
|
</blockquote></para>
|
|
</blockquote></para>
|
|
|
|
<para>Since the SERVER PORT is generally the only port known ahead
|
|
of time, we must categorize traffic from the server to the client
|
|
using the SOURCE PORT.</para>
|
|
</blockquote></para>
|
|
</important>
|
|
|
|
<para>The fwmark classifier provides a convenient way to classify
|
|
packets for traffic shaping. The <quote>/etc/shorewall/tcrules</quote>
|
|
file is used for specifying these marks in a tabular fashion. For an
|
|
in-depth look at the packet marking facility in Netfilter/Shorewall,
|
|
please see <ulink url="PacketMarking.html">this article</ulink>.</para>
|
|
|
|
<para><emphasis role="bold">For marking forwarded traffic, you must
|
|
either set MARK_IN_FORWARD_CHAIN=Yes shorewall.conf or by using the :F
|
|
qualifier (see below).</emphasis></para>
|
|
|
|
<para>Columns in the file are as follows:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>ACTION - ACTION (previously called MARK) specifies the mark
|
|
value is to be assigned in case of a match. This is an integer in
|
|
the range 1-255 (1-16383 if you set WIDE_TC_MARKS=Yes or TC_BITS=14
|
|
in <ulink url="manpages/shorewall.conf.html">shorewall.conf</ulink>
|
|
(5) ).</para>
|
|
|
|
<note>
|
|
<para>In Shorewall 4.4.26, WIDE_TC_MARKS was superseded by TC_BITS
|
|
which specifies the width in bits of the traffic shaping mark
|
|
field. The default is based on the setting of WIDE_TC_MARKS so as
|
|
to provide upward compatibility.</para>
|
|
</note>
|
|
|
|
<para>This value may be optionally followed by <quote>:</quote> and
|
|
either <quote>F</quote>, <quote>P</quote> or "T" to designate that
|
|
the marking will occur in the FORWARD, PREROUTING or POSTROUTING
|
|
chains respectively. If this additional specification is omitted,
|
|
the chain used to mark packets will be determined as follows:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>If the SOURCE is
|
|
$FW[:<<emphasis>address</emphasis>>], then the rule is
|
|
inserted in the OUTPUT chain.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Otherwise, the chain is determined by the setting of the
|
|
MARK_IN_FORWARD_CHAIN option in shorewall.conf.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<note>
|
|
<para><emphasis role="bold">Use the 'T' qualifier if you want the
|
|
rule to apply equally to traffic being routed through the firewall
|
|
and to traffic originating on the firewall
|
|
itself.</emphasis></para>
|
|
</note>
|
|
|
|
<para>Normally, the mark is applied to the packet. If you follow the
|
|
mark value with ":" and "C", then the mark is applied to the
|
|
connection. "C" can be combined with "F", "P" or "T" to designate
|
|
that the connection should be marked in a particular chain (e.g.,
|
|
"CF", "CP", "CT").</para>
|
|
|
|
<para>There are additional special values available:</para>
|
|
|
|
<orderedlist numeration="loweralpha">
|
|
<listitem>
|
|
<para><emphasis
|
|
role="bold">RESTORE</emphasis>[/<emphasis>mask</emphasis>] --
|
|
restore the packet's mark from the connection's mark using the
|
|
supplied mask if any. Your kernel and iptables must include
|
|
CONNMARK support.</para>
|
|
|
|
<para>As above, may be followed by <emphasis
|
|
role="bold">:P</emphasis>, <emphasis role="bold">:F</emphasis>
|
|
or <emphasis role="bold">:T</emphasis>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><emphasis
|
|
role="bold">SAVE</emphasis>[/<emphasis>mask</emphasis>] -- save
|
|
the packet's mark to the connection's mark using the supplied
|
|
mask if any. Your kernel and iptables must include CONNMARK
|
|
support.</para>
|
|
|
|
<para>As above, may be followed by <emphasis
|
|
role="bold">:P</emphasis>, <emphasis role="bold">:F</emphasis>
|
|
or <emphasis role="bold">:T</emphasis>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><emphasis role="bold">CONTINUE</emphasis> Don't process
|
|
any more marking rules in the table.</para>
|
|
|
|
<para>As above, may be followed by <emphasis
|
|
role="bold">:P</emphasis>, <emphasis role="bold">:F</emphasis>
|
|
or <emphasis role="bold">:T</emphasis>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><emphasis role="bold">COMMENT</emphasis> -- the rest of
|
|
the line will be attached as a comment to the Netfilter rule(s)
|
|
generated by the following entries. The comment will appear
|
|
delimited by "/* ... */" in the output of <command>shorewall
|
|
show mangle</command></para>
|
|
|
|
<para>To stop the comment from being attached to further rules,
|
|
simply include COMMENT on a line by itself.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>To use CLASSIFY, your kernel and iptables must include
|
|
CLASSIFY target support. In that case, this column contains a
|
|
classification (classid) of the form <major>:<minor>
|
|
where <major> and <minor> are integers. Corresponds to
|
|
the 'class' specification in these traffic shaping modules:</para>
|
|
|
|
<simplelist>
|
|
<member>atm</member>
|
|
|
|
<member>cbq</member>
|
|
|
|
<member>dsmark</member>
|
|
|
|
<member>pfifo_fast</member>
|
|
|
|
<member>htb</member>
|
|
|
|
<member>prio</member>
|
|
</simplelist>
|
|
|
|
<para>Classification occurs in the POSTROUTING chain <emphasis
|
|
role="bold">except</emphasis> when the SOURCE contains
|
|
$FW[:<<emphasis>address</emphasis>>] in which case, the
|
|
classify action takes place in the OUTPUT chain. When used with the
|
|
builtin traffic shaper, the <major> class is the interface
|
|
number and the <minor> class is either:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>Constructed by Shorewall. The method of construction
|
|
depends on the setting of WIDE_TC_MARKS (TC_BITS in shorewall
|
|
4.4.26 and later) in (<ulink
|
|
url="manpages/shorewall.conf.html">shorewall.conf</ulink>
|
|
(5)).</para>
|
|
|
|
<para>When WIDE_TC_MARKS=No (the default) or TC_BITS > 14,
|
|
the <minor> class is:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>the MARK value of the class preceded by the number "1"
|
|
or "10" (MARK value 1 is <minor> class 11, MARK value
|
|
22 is <minor> class 122, and so on). "10" is used
|
|
where there are more than 10 devices defined in <link
|
|
linkend="tcdevices">/etc/shorewall/tcdevices</link>.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>When WIDE_TC_MARKS=Yes (TC_BITS >= 14), the
|
|
<minor> class is assigned sequentially beginning with
|
|
2.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class number, if specified.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>SOURCE - Source of the packet.</para>
|
|
|
|
<para>May be:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>An interface name - matches traffic entering the firewall
|
|
on the specified interface. May not be used in classify rules or
|
|
in rules using the :T chain qualifier.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>A comma-separated list of host or network IP addresses or
|
|
MAC addresses. <emphasis role="bold">This form will not match
|
|
traffic that originates on the firewall itself unless either
|
|
<major><minor> or the :T chain qualifier is used in
|
|
the ACTION column.</emphasis></para>
|
|
|
|
<para>Examples:<simplelist>
|
|
<member>0.0.0.0/0</member>
|
|
</simplelist></para>
|
|
|
|
<para><simplelist>
|
|
<member>192.168.1.0/24, 172.20.4.0/24</member>
|
|
</simplelist></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>An interface name followed by a colon (":") followed by a
|
|
comma-separated list of host or network IP addresses or MAC
|
|
addresses. May not be used in classify rules or in rules using
|
|
the :T chain qualifier.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>$FW optionally followed by a colon (":") and a
|
|
comma-separated list of host or network IP addresses. matches
|
|
packets originating on the firewall. May not be used with a
|
|
chain qualifier (:P, :F, etc.) in the ACTION column.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>MAC addresses must be prefixed with "~" and use "-" as a
|
|
separator.</para>
|
|
|
|
<para>Example: ~00-A0-C9-15-39-78</para>
|
|
|
|
<para>If your kernel includes iprange match support, then address
|
|
ranges may be included in the address lists.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>DEST - Destination of the packet.</para>
|
|
|
|
<para>May be:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>An interface name. May not be used in the PREROUTING chain
|
|
(:P in the mark column or no chain qualifier and
|
|
MARK_IN_FORWARD_CHAIN=No in <ulink
|
|
url="manpages/shorewall.conf">shorewall.conf</ulink> (5)). The
|
|
interface name may be optionally followed by a colon (":") and
|
|
an IP address list.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>A comma-separated list of host or network IP addresses.
|
|
The list may include ip address ranges if your kernel and
|
|
iptables include iprange support.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>PROTO - Protocol - Must be "tcp", "udp", "icmp", "ipp2p",
|
|
"ipp2p:udp", "ipp2p:all" a number, or "all". "ipp2p" requires ipp2p
|
|
match support in your kernel and iptables.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>PORT(S) - Destination Ports. A comma-separated list of Port
|
|
names (from /etc/services), port numbers or port ranges; if the
|
|
protocol is "icmp", this column is interpreted as the destination
|
|
icmp-type(s).</para>
|
|
|
|
<para>If the protocol is ipp2p, this column is interpreted as an
|
|
ipp2p option without the leading "--" (example "bit" for
|
|
bit-torrent). If no PORT is given, "ipp2p" is assumed. Note that the
|
|
xtables-addons version of IPP2P does not support the "ipp2p" option;
|
|
if the column is empty or contains "ipp2p" when using that version
|
|
of IPP2P, Shorewall will substitute "edk,kazaa,gnu,dc".</para>
|
|
|
|
<para>This column is ignored if PROTOCOL = all but must be entered
|
|
if any of the following field is supplied. In that case, it is
|
|
suggested that this field contain "-"</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>CLIENT PORT(S) - (Optional) Port(s) used by the client. If
|
|
omitted, any source port is acceptable. Specified as a
|
|
comma-separate list of port names, port numbers or port
|
|
ranges.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>USER/GROUP (Optional) This column may only be non-empty if the
|
|
SOURCE is the firewall itself. When this column is non-empty, the
|
|
rule applies only if the program generating the output is running
|
|
under the effective user and/or group. It may contain :</para>
|
|
|
|
<para>[!][<user name or number>]:[<group name or
|
|
number>][+<program name>]</para>
|
|
|
|
<para>The colon is optional when specifying only a user.</para>
|
|
|
|
<para>Examples:</para>
|
|
|
|
<programlisting>joe #program must be run by joe
|
|
:kids #program must be run by a member of the 'kids' group
|
|
!:kids #program must not be run by a member of the 'kids' group
|
|
+upnpd #program named upnpd (This feature was removed from Netfilter in kernel version 2.6.14).</programlisting>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>TEST (Optional) Defines a test on the existing packet or
|
|
connection mark. The rule will match only if the test returns true.
|
|
Tests have the format [!]<value>[/<mask>][:C]</para>
|
|
|
|
<para>Where:</para>
|
|
|
|
<simplelist>
|
|
<member>! Inverts the test (not equal)</member>
|
|
|
|
<member><value> Value of the packet or connection
|
|
mark.</member>
|
|
|
|
<member><mask> A mask to be applied to the mark before
|
|
testing</member>
|
|
|
|
<member>:C Designates a connection mark. If omitted, the packet
|
|
mark's value is tested.</member>
|
|
</simplelist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>LENGTH (Optional) This field, if present, allows you to match
|
|
the length of a packet against a specific value or range of values.
|
|
A range is specified in the form <min>:<max> where
|
|
either <min> or <max> (but not both) may be omitted. If
|
|
<min> is omitted, then 0 is assumed; if <max> is
|
|
omitted, than any packet that is <min> or longer will
|
|
match.</para>
|
|
|
|
<para>You must have iptables length support for this to work. If you
|
|
let it empty or place an "-" here, no length match will be
|
|
done.</para>
|
|
|
|
<para>Examples: 1024, 64:1500, :100</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>TOS (Optional) Type of Service. Either a standard name, or a
|
|
numeric value to match.</para>
|
|
|
|
<blockquote>
|
|
<simplelist>
|
|
<member>Minimize-Delay (16)</member>
|
|
|
|
<member>Maximize-Throughput (8)</member>
|
|
|
|
<member>Maximize-Reliability (4)</member>
|
|
|
|
<member>Minimize-Cost (2)</member>
|
|
|
|
<member>Normal-Service (0)</member>
|
|
</simplelist>
|
|
</blockquote>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>HELPER (Optional). Names one of the Netfilter protocol helper
|
|
modules such as <emphasis>ftp</emphasis>, <emphasis>sip</emphasis>,
|
|
<emphasis>amanda</emphasis>, etc.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>HEADERS (Optioinal, Shorewall6 only, added in Shorewall
|
|
4.4.15). List of IPv6 headers that may appear in packets. See <ulink
|
|
url="manpages6/shorewall6-tcrules.html">shorewall6-tcrules</ulink>
|
|
(5) for details.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<example id="Example1">
|
|
<title></title>
|
|
|
|
<para>All packets arriving on eth1 should be marked with 1. All
|
|
packets arriving on eth2 and eth3 should be marked with 2. All packets
|
|
originating on the firewall itself should be marked with 3.</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S)
|
|
1 eth1 0.0.0.0/0 all
|
|
2 eth2 0.0.0.0/0 all
|
|
2 eth3 0.0.0.0/0 all
|
|
3 $FW 0.0.0.0/0 all</programlisting>
|
|
</example>
|
|
|
|
<example id="Example2">
|
|
<title></title>
|
|
|
|
<para>All GRE (protocol 47) packets destined for 155.186.235.151
|
|
should be marked with 12.</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S)
|
|
12:T 0.0.0.0/0 155.182.235.151 47</programlisting>
|
|
</example>
|
|
|
|
<example id="Example3">
|
|
<title></title>
|
|
|
|
<para>All SSH request packets originating in 192.168.1.0/24 and
|
|
destined for 155.186.235.151 should be marked with 22.</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S)
|
|
22:T 192.168.1.0/24 155.182.235.151 tcp 22</programlisting>
|
|
</example>
|
|
|
|
<example id="Example4">
|
|
<title></title>
|
|
|
|
<para>All SSH packets packets going out of the first device in in
|
|
/etc/shorewall/tcdevices should be assigned to the class with mark
|
|
value 10.</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S) CLIENT
|
|
# PORT(S)
|
|
1:110 0.0.0.0/0 0.0.0.0/0 tcp 22
|
|
1:110 0.0.0.0/0 0.0.0.0/0 tcp - 22</programlisting>
|
|
</example>
|
|
|
|
<example id="Example5">
|
|
<title></title>
|
|
|
|
<para>Mark all ICMP echo traffic with packet mark 1. Mark all peer to
|
|
peer traffic with packet mark 4.</para>
|
|
|
|
<para>This is a little more complex than otherwise expected. Since the
|
|
ipp2p module is unable to determine all packets in a connection are
|
|
P2P packets, we mark the entire connection as P2P if any of the
|
|
packets are determined to match. We assume packet/connection mark 0 to
|
|
means unclassified. Traffic originating on the firewall is not covered
|
|
by this example.</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S) CLIENT USER/ TEST
|
|
# PORT(S) GROUP
|
|
1 0.0.0.0/0 0.0.0.0/0 icmp echo-request
|
|
1 0.0.0.0/0 0.0.0.0/0 icmp echo-reply
|
|
|
|
RESTORE 0.0.0.0/0 0.0.0.0/0 all - - - 0
|
|
CONTINUE 0.0.0.0/0 0.0.0.0/0 all - - - !0
|
|
4 0.0.0.0/0 0.0.0.0/0 ipp2p:all
|
|
SAVE 0.0.0.0/0 0.0.0.0/0 all - - - !0</programlisting>
|
|
|
|
<para>The last four rules can be translated as:</para>
|
|
|
|
<blockquote>
|
|
<para>"If a packet hasn't been classified (packet mark is 0), copy
|
|
the connection mark to the packet mark. If the packet mark is set,
|
|
we're done. If the packet is P2P, set the packet mark to 4. If the
|
|
packet mark has been set, save it to the connection mark."</para>
|
|
</blockquote>
|
|
</example>
|
|
|
|
<example>
|
|
<title></title>
|
|
|
|
<para>Mark all forwarded VOIP connections with connection mark 1 and
|
|
ensure that all VOIP packets also receive that mark (assumes that
|
|
nf_conntrack_sip is loaded).</para>
|
|
|
|
<programlisting>#ACTION SOURCE DESTINATION PROTOCOL PORT(S) CLIENT USER/ TEST CONNBYTES TOS HELPER
|
|
# PORT(S) GROUP
|
|
RESTORE 0.0.0.0/0 0.0.0.0/0 all - - - 0
|
|
CONTINUE 0.0.0.0/0 0.0.0.0/0 all - - - !0
|
|
1 0.0.0.0/0 0.0.0.0/0 all - - - - - - sip
|
|
SAVE 0.0.0.0/0 0.0.0.0/0 all - - - !0</programlisting>
|
|
</example>
|
|
</section>
|
|
|
|
<section id="ppp">
|
|
<title>ppp devices</title>
|
|
|
|
<para>If you use ppp/pppoe/pppoa) to connect to your Internet provider
|
|
and you use traffic shaping you need to restart shorewall traffic
|
|
shaping. The reason for this is, that if the ppp connection gets
|
|
restarted (and it usually does this at least daily), all
|
|
<quote>tc</quote> filters/qdiscs related to that interface are
|
|
deleted.</para>
|
|
|
|
<para>The easiest way to achieve this, is just to restart shorewall once
|
|
the link is up. To achieve this add a small executable script
|
|
to<quote>/etc/ppp/ip-up.d</quote>.</para>
|
|
|
|
<programlisting>#! /bin/sh
|
|
|
|
/sbin/shorewall refresh</programlisting>
|
|
</section>
|
|
|
|
<section>
|
|
<title>Sharing a TC configuration between Shorewall and
|
|
Shorewall6</title>
|
|
|
|
<para>Beginning with Shorewall 4.4.15, the traffic-shaping configuration
|
|
in the tcdevices, tcclasses and tcfilters files can be shared between
|
|
Shorewall and Shorewall6. Only one of the products can control the
|
|
configuration but the other can configure CLASSIFY rules in its own
|
|
tcrules file that refer to the shared classes.</para>
|
|
|
|
<para>To defined the configuration in Shorewall and shared it with
|
|
Shorewall6:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>Set TC_ENABLED=Internal in <ulink
|
|
url="manpages/shorewall.conf.html">shorewall.conf</ulink>
|
|
(5).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Set TC_ENABLED=Shared in <ulink
|
|
url="manpages6/shorewall6.conf.html">shorewall6.conf</ulink>
|
|
(5).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Create symbolic links from /etc/shorewall6 to
|
|
/etc/shorewall/tcdevices and /etc/shorewall/tcclasses:</para>
|
|
|
|
<programlisting>ln -s ../shorewall/tcdevices /etc/shorewall6/tcdevices
|
|
ln -s ../shorewall/tcclasses /etc/shorewall6/tcclasses</programlisting>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>If you need to define IPv6 tcfilter entries, do so in
|
|
/etc/shorewall/tcfilters. That file now allows entries that apply to
|
|
IPv6.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>Shorewall6 compilations to have access to the tcdevices and
|
|
tcclasses files although it will create no output. That access allows
|
|
CLASSIFY rules in /etc/shorewall6/tcrules to be validated against the TC
|
|
configuration.</para>
|
|
|
|
<para>In this configuration, it is Shorewall that controls TC
|
|
configuration (except for IPv6 tcrules). You can reverse the settings in
|
|
the files if you want to control the configuration using
|
|
Shorewall6.</para>
|
|
</section>
|
|
|
|
<section id="perIP">
|
|
<title>Per-IP Traffic Shaping</title>
|
|
|
|
<para>Some network administrators feel that they have to divy up their
|
|
available bandwidth by IP address rather than by prioritizing the
|
|
traffic based on the type of traffic. This gets really awkward when
|
|
there are a large number of local IP addresses.</para>
|
|
|
|
<para>This section describes the Shorewall facility for making this
|
|
configuration less tedious (and a lot more efficient). Note that it
|
|
requires that you <ulink url="Dynamic.html#xtables-addons">install
|
|
xtables-addons</ulink>. So before you try this facility, we suggest that
|
|
first you add the following OPTION to each external interface described
|
|
in /etc/shorewall/tcdevices:</para>
|
|
|
|
<programlisting>flow=nfct-src</programlisting>
|
|
|
|
<para>If you shape traffic on your internal interface(s), then add this
|
|
to their entries:</para>
|
|
|
|
<programlisting>flow=dst</programlisting>
|
|
|
|
<para>You may find that this simple change is all that is needed to
|
|
control bandwidth hogs like Bit Torrent. If it doesn't, then proceed as
|
|
described in this section.</para>
|
|
|
|
<para>The facility has two components:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>An IPMARK MARKing command in
|
|
<filename>/etc/shorewall/tcrules</filename>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>An <emphasis role="bold">occurs</emphasis> OPTION in
|
|
/etc/shorewall/tcclasses.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>The facility is currently only available with IPv4.</para>
|
|
|
|
<para>In a sense, the IPMARK target is more like an IPCLASSIFY target in
|
|
that the mark value is later interpreted as a class ID. A packet mark is
|
|
32 bits wide; so is a class ID. The <emphasis>major</emphasis> class
|
|
occupies the high-order 16 bits and the <emphasis>minor</emphasis> class
|
|
occupies the low-order 16 bits. So the class ID 1:4ff (remember that
|
|
class IDs are always in hex) is equivalent to a mark value of 0x104ff.
|
|
Remember that Shorewall uses the interface number as the
|
|
<emphasis>major</emphasis> number where the first interface in tcdevices
|
|
has <emphasis>major</emphasis> number 1, the second has
|
|
<emphasis>major</emphasis> number 2, and so on.</para>
|
|
|
|
<para>The IPMARK target assigns a mark to each matching packet based on
|
|
the either the source or destination IP address. By default, it assigns
|
|
a mark value equal to the low-order 8 bits of the source address.</para>
|
|
|
|
<para>The syntax is as follows:</para>
|
|
|
|
<blockquote>
|
|
<para><emphasis role="bold">IPMARK</emphasis>[<emphasis
|
|
role="bold">(</emphasis>[{<emphasis
|
|
role="bold">src</emphasis>|<emphasis
|
|
role="bold">dst</emphasis>}][<emphasis
|
|
role="bold">,</emphasis>[<emphasis>mask1</emphasis>][,[<emphasis>mask2</emphasis>][<emphasis
|
|
role="bold">,</emphasis>[<emphasis>shift</emphasis>]]]]<emphasis
|
|
role="bold">)</emphasis>]</para>
|
|
</blockquote>
|
|
|
|
<para>Default values are:</para>
|
|
|
|
<simplelist>
|
|
<member>src</member>
|
|
|
|
<member>mask1 = 0xFF</member>
|
|
|
|
<member>mask2 = 0x00</member>
|
|
|
|
<member>shift = 0</member>
|
|
</simplelist>
|
|
|
|
<para><emphasis role="bold">src</emphasis> and <emphasis
|
|
role="bold">dst</emphasis> specify whether the mark is to be based on
|
|
the source or destination address respectively. The selected address is
|
|
first shifted right by <emphasis>shift</emphasis>, then LANDed with
|
|
<emphasis>mask1</emphasis> and then LORed with
|
|
<emphasis>mask2</emphasis>. The <emphasis>shift</emphasis> argument is
|
|
intended to be used primarily with IPv6 addresses.</para>
|
|
|
|
<para>Example:</para>
|
|
|
|
<programlisting>IPMARK(src,0xff,0x10100)
|
|
|
|
Source IP address is 192.168.4.3 = 0xc0a80403
|
|
|
|
0xc0a80403 >> 0 = 0xc0a80403
|
|
0xc0a80403 LAND 0xFF = 0x03
|
|
0x03 LOR 0x10100 = 0x10103
|
|
|
|
So the mark value is 0x10103 which corresponds to class id 1:103.</programlisting>
|
|
|
|
<para>It is important to realize that, while class IDs are composed of a
|
|
<emphasis>major</emphasis> and a <emphasis>minor</emphasis> value, the
|
|
set of <emphasis>minor</emphasis> values must be unique. You must keep
|
|
this in mind when deciding how to map IP addresses to class IDs. For
|
|
example, suppose that your internal network is 192.168.1.0/29 (host IP
|
|
addresses 192.168.1.1 - 192.168.1.6). Your first notion might be to use
|
|
IPMARK(src,0xFF,0x10000) so as to produce class IDs 1:1 through 1:6. But
|
|
1:1 is the class ID of the base HTB class on interface 1. So you might
|
|
chose instead to use IPMARK(src,0xFF,0x10100) as shown in the example
|
|
above so as to avoid minor class 1.</para>
|
|
|
|
<para>The <emphasis role="bold">occurs</emphasis> option in
|
|
<filename>/etc/shorewall/tcclasses</filename> causes the class
|
|
definition to be replicated many times.</para>
|
|
|
|
<para>The synax is:</para>
|
|
|
|
<blockquote>
|
|
<para><emphasis
|
|
role="bold">occurs=</emphasis><emphasis>number</emphasis></para>
|
|
</blockquote>
|
|
|
|
<para>When <emphasis role="bold">occurs</emphasis> is used:</para>
|
|
|
|
<orderedlist numeration="loweralpha">
|
|
<listitem>
|
|
<para>The associated device may not have the <emphasis
|
|
role="bold">classify</emphasis> option.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class may not be the default class.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The class may not have any <emphasis
|
|
role="bold">tos=</emphasis> options (including <emphasis
|
|
role="bold">tcp-ack</emphasis>).</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>The class should not specify a MARK value. Any MARK value given is
|
|
ignored with a warning. The RATE and CEIL parameters apply to each
|
|
instance of the class. So the total RATE represented by an entry with
|
|
<emphasis role="bold">occurs</emphasis> will be the listed RATE
|
|
multiplied by <emphasis>number</emphasis>.</para>
|
|
|
|
<para>Example:</para>
|
|
|
|
<para><filename>/etc/shorewall/tcdevices</filename>:</para>
|
|
|
|
<programlisting>#INTERFACE IN-BANDWIDTH OUT-BANDWIDTH
|
|
eth0 100mbit 100mbit</programlisting>
|
|
|
|
<para><filename>/etc/shorewall/tcclasses</filename>:</para>
|
|
|
|
<programlisting>#DEVICE MARK RATE CEIL PRIORITY OPTIONS
|
|
eth0:101 - 1kbit 230kbit 4 occurs=6</programlisting>
|
|
|
|
<para>The above defines 6 classes with class IDs 0x101-0x106. Each class
|
|
has a guaranteed rate of 1kbit/second and a ceiling of 230kbit.</para>
|
|
|
|
<para><filename>/etc/shoreall/tcrules</filename>:</para>
|
|
|
|
<programlisting>#ACTION SOURCE DEST
|
|
IPMARK(src,0xff,0x10100):F 192.168.1.0/29 eth0</programlisting>
|
|
|
|
<para>This facility also alters the way in which Shorewall generates a
|
|
class number when none is given. Prior to the implementation of this
|
|
facility, the class number was constructed by concatinating the MARK
|
|
value with the either '1' or '10'. '10' was used when there were more
|
|
than 10 devices defined in
|
|
<filename>/etc/shorewall/tcdevices</filename>.</para>
|
|
|
|
<para>With this facility, a new method is added; class numbers are
|
|
assigned sequentially beginning with 2. The WIDE_TC_MARKS option in
|
|
<filename>shorewall.conf</filename> selects which construction to use.
|
|
WIDE_TC_MARKS=No (the default) produces pre-Shorewall 4.4 behavior.
|
|
WIDE_TC_MARKS=Yes (TC_BITS >= 14 in Shorewall 4.4.26 and later)
|
|
produces the new behavior.</para>
|
|
</section>
|
|
|
|
<section id="Real">
|
|
<title>Real life examples</title>
|
|
|
|
<section>
|
|
<title>A Shorewall User's Experience</title>
|
|
|
|
<para>Chuck Kollars has provided <ulink
|
|
url="http://www.ckollars.org/shaping.html">an excellent
|
|
writeup</ulink> about his traffic shaping experiences.</para>
|
|
</section>
|
|
|
|
<section id="Wondershaper">
|
|
<title>Configuration to replace Wondershaper</title>
|
|
|
|
<para>You are able to fully replace the wondershaper script by using
|
|
the buitin traffic control.. In this example it is assumed that your
|
|
interface for your Internet connection is ppp0 (for DSL), if you use
|
|
another connection type, you have to change it. You also need to
|
|
change the settings in the tcdevices.wondershaper file to reflect your
|
|
line speed. The relevant lines of the config files follow here. Please
|
|
note that this is just a 1:1 replacement doing exactly what
|
|
wondershaper should do. You are free to change it...</para>
|
|
|
|
<section id="realtcd">
|
|
<title>tcdevices file</title>
|
|
|
|
<programlisting>#INTERFACE IN-BANDWITH OUT-BANDWIDTH
|
|
ppp0 5000kbit 500kbit</programlisting>
|
|
</section>
|
|
|
|
<section id="realtcc">
|
|
<title>tcclasses file</title>
|
|
|
|
<programlisting>#INTERFACE MARK RATE CEIL PRIORITY OPTIONS
|
|
ppp0 1 5*full/10 full 1 tcp-ack,tos-minimize-delay
|
|
ppp0 2 3*full/10 9*full/10 2 default
|
|
ppp0 3 2*full/10 8*full/10 2</programlisting>
|
|
</section>
|
|
|
|
<section id="realtcr">
|
|
<title>tcrules file</title>
|
|
|
|
<programlisting>#ACTION SOURCE DEST PROTO PORT(S) CLIENT USER
|
|
# PORT(S)
|
|
1:F 0.0.0.0/0 0.0.0.0/0 icmp echo-request
|
|
1:F 0.0.0.0/0 0.0.0.0/0 icmp echo-reply
|
|
# mark traffic which should have a lower priority with a 3:
|
|
# mldonkey
|
|
3 0.0.0.0/0 0.0.0.0/0 udp - 4666</programlisting>
|
|
|
|
<para>Wondershaper allows you to define a set of hosts and/or ports
|
|
you want to classify as low priority. To achieve this , you have to
|
|
add these hosts to tcrules and set the mark to 3 (true if you use
|
|
the example configuration files).</para>
|
|
</section>
|
|
|
|
<section id="lowpro">
|
|
<title>Setting hosts to low priority</title>
|
|
|
|
<para>lets assume the following settings from your old wondershaper
|
|
script (don't assume these example values are really useful, they
|
|
are only used for demonstrating ;-):</para>
|
|
|
|
<programlisting>
|
|
# low priority OUTGOING traffic - you can leave this blank if you want
|
|
# low priority source netmasks
|
|
NOPRIOHOSTSRC="192.168.1.128/25 192.168.3.28"
|
|
|
|
# low priority destination netmasks
|
|
NOPRIOHOSTDST=60.0.0.0/24
|
|
|
|
# low priority source ports
|
|
NOPRIOPORTSRC="6662 6663"
|
|
|
|
# low priority destination ports
|
|
NOPRIOPORTDST="6662 6663" </programlisting>
|
|
|
|
<para>This would result in the following additional settings to the
|
|
tcrules file:</para>
|
|
|
|
<programlisting>3 192.168.1.128/25 0.0.0.0/0 all
|
|
3 192.168.3.28 0.0.0.0/0 all
|
|
3 0.0.0.0/0 60.0.0.0/24 all
|
|
3 0.0.0.0/0 0.0.0.0/0 udp 6662,6663
|
|
3 0.0.0.0/0 0.0.0.0/0 udp - 6662,6663
|
|
3 0.0.0.0/0 0.0.0.0/0 tcp 6662,6663
|
|
3 0.0.0.0/0 0.0.0.0/0 tcp - 6662,6663</programlisting>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="simiple">
|
|
<title>A simple setup</title>
|
|
|
|
<para>This is a simple setup for people sharing an Internet connection
|
|
and using different computers for this. It just basically shapes
|
|
between 2 hosts which have the ip addresses 192.168.2.23 and
|
|
192.168.2.42</para>
|
|
|
|
<section id="simpletcd">
|
|
<title>tcdevices file</title>
|
|
|
|
<programlisting>#INTERFACE IN-BANDWITH OUT-BANDWIDTH
|
|
ppp0 6000kbit 700kbit</programlisting>
|
|
|
|
<para>We have 6mbit down and 700kbit upstream.</para>
|
|
</section>
|
|
|
|
<section id="simpletcc">
|
|
<title>tcclasses file</title>
|
|
|
|
<programlisting>#INTERFACE MARK RATE CEIL PRIORITY OPTIONS
|
|
ppp0 1 10kbit 50kbit 1 tcp-ack,tos-minimize-delay
|
|
ppp0 2 300kbit full 2
|
|
ppp0 3 300kbit full 2
|
|
ppp0 4 90kbit 200kbit 3 default</programlisting>
|
|
|
|
<para>We add a class for tcp ack packets with highest priority, so
|
|
that downloads are fast. The following 2 classes share most of the
|
|
bandwidth between the 2 hosts, if the connection is idle, they may
|
|
use full speed. As the hosts should be treated equally they have the
|
|
same priority. The last class is for the remaining traffic.</para>
|
|
</section>
|
|
|
|
<section id="simpletcr">
|
|
<title>tcrules file</title>
|
|
|
|
<programlisting>#ACTION SOURCE DEST PROTO PORT(S) CLIENT USER
|
|
# PORT(S)
|
|
1:F 0.0.0.0/0 0.0.0.0/0 icmp echo-request
|
|
1:F 0.0.0.0/0 0.0.0.0/0 icmp echo-reply
|
|
2:F 192.168.2.23 0.0.0.0/0 all
|
|
3:F 192.168.2.42 0.0.0.0/0 all</programlisting>
|
|
|
|
<para>We mark icmp ping and replies so they will go into the fast
|
|
interactive class and set a mark for each host.</para>
|
|
</section>
|
|
</section>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="Xen">
|
|
<title>A Warning to Xen Users</title>
|
|
|
|
<para>If you are running traffic shaping in your dom0 and traffic shaping
|
|
doesn't seem to be limiting outgoing traffic properly, it may be due to
|
|
"checksum offloading" in your domU(s). Check the output of "shorewall show
|
|
tc". Here's an excerpt from the output of that command:</para>
|
|
|
|
<programlisting>class htb 1:130 parent 1:1 leaf 130: prio 3 quantum 1500 rate 76000bit <emphasis
|
|
role="bold">ceil 230000bit</emphasis> burst 1537b/8 mpu 0b overhead 0b cburst 1614b/8 mpu 0b overhead 0b level 0
|
|
Sent 559018700 bytes 75324 pkt (dropped 0, overlimits 0 requeues 0)
|
|
<emphasis role="bold">rate 299288bit</emphasis> 3pps backlog 0b 0p requeues 0
|
|
lended: 53963 borrowed: 21361 <emphasis role="bold">giants: 90174</emphasis>
|
|
tokens: -26688 ctokens: -14783</programlisting>
|
|
|
|
<para>There are two obvious problems in the above output:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>The rate (299288) is considerably larger than the ceiling
|
|
(230000).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>There are a large number (90174) of giants reported.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>This problem will be corrected by disabling "checksum offloading" in
|
|
your domU(s) using the <command>ethtool</command> utility. See the <ulink
|
|
url="XenMyWay-Routed.html">one of the Xen articles</ulink> for
|
|
instructions.</para>
|
|
</section>
|
|
|
|
<section id="HFSC">
|
|
<title>An HFSC Example</title>
|
|
|
|
<para>As mentioned at the top of this article, there is an excellent
|
|
introduction to HFSC at <ulink
|
|
url="http://linux-ip.net/articles/hfsc.en/">http://linux-ip.net/articles/hfsc.en/</ulink>.
|
|
At the end of that article are 'tc' commands that implement the
|
|
configuration in the article. Those tc commands correspond to the
|
|
following Shorewall traffic shaping configuration.</para>
|
|
|
|
<para><filename>/etc/shorewall/tcdevices</filename>:</para>
|
|
|
|
<programlisting>#INTERFACE IN-BANDWITH OUT-BANDWIDTH OPTIONS
|
|
eth0 - 1000kbit hfsc</programlisting>
|
|
|
|
<para><filename>/etc/shorewall/tcclasses</filename>:</para>
|
|
|
|
<programlisting>#INTERFACE:CLASS MARK RATE: CEIL PRIORITY OPTIONS
|
|
# DMAX:UMAX
|
|
1:10 1 500kbit full 1
|
|
1:20 2 500kbit full 1
|
|
1:10:11 3 400kbit:53ms:1500b full 2
|
|
1:10:12 4 100kbit:30ms:1500b full 2</programlisting>
|
|
|
|
<para>The following sub-section offers some notes about the
|
|
article.</para>
|
|
|
|
<section id="MajicNumbers">
|
|
<title>Where Did all of those Magic Numbers come from?</title>
|
|
|
|
<para>As you read the article, numbers seem to be introduced out of thin
|
|
air. I'll try to shed some light on those.</para>
|
|
|
|
<para>There is very clear development of these numbers:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>12ms to transfer a 1500b packet at 1000kbits/second.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>100kbits per second with 1500b packets, requires 8 packets per
|
|
second.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>A packet from class 1:12 must be sent every 120ms.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Total transmit delay can be no more than 132ms (120 +
|
|
12).</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>We then learn that the queuing latency can be reduced to 30ms if
|
|
we use a two-part service curve whose first part is 400kbits/second.
|
|
Where did those come from?</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>The latency is calculated from the rate. If it takes 12ms to
|
|
transmit a 1500 byte packet at 1000kbits/second, it takes 30ms to
|
|
transmit a 1500b at 400kbits/second.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>For the slope of the first part of the service curve, in
|
|
theory we can pick any number between 100 (the rate of class 1:12)
|
|
and 500 (the rate of the parent class) with higher numbers providing
|
|
lower latency.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The final curious number is the latency for class 1:11 - 52.5ms.
|
|
It is a consequence of everything that has gone before.</para>
|
|
|
|
<para>To acheive 400kbits/second with 1500-byte packets, 33.33 packets
|
|
per second are required. So a packet from class 1:11 must be sent every
|
|
30 ms. As the article says, "...the maximum transmission delay of this
|
|
class increases from 30ms to a total of 52.5 ms.". So we are looking for
|
|
an additional 22.5 ms.</para>
|
|
|
|
<para>Assume that both class 1:11 and 1:12 transmit for 30 ms at
|
|
400kbits/second. That is a total of 800kbits/second for 30ms. So Class
|
|
1:11 is punished for the excess. How long is the punishment? The two
|
|
classes sent 24,000 bits in 30ms; they are only allowed 0.030 * 500,000
|
|
= 15,000. So they are 9,000 bits over their quota. The amount of time
|
|
required to transmit 9,000 bits at 400,000 bits/second is
|
|
22.5ms!.</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="IFB">
|
|
<title>Intermediate Functional Block (IFB) Devices</title>
|
|
|
|
<para>The principles behind an IFB is fairly simple:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>It looks like a network interface although it is never given an
|
|
IPv4 configuration.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Because it is a network interface, queuing disciplines can be
|
|
associated with an IFB.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The magic of an IFB comes in the fact that a filter may be defined
|
|
on a real network interface such that each packet that arrives on that
|
|
interface is queued for the IFB! In that way, the IFB provides a means for
|
|
shaping input traffic.</para>
|
|
|
|
<para>To use an IFB, you must have IFB support in your kernel
|
|
(configuration option CONFIG_IFB). Assuming that you have a modular
|
|
kernel, the name of the IFB module is 'ifb' and may be loaded using the
|
|
command <command>modprobe ifb</command> (if you have modprobe installed)
|
|
or <command>insmod /path/to/module/ifb</command>.</para>
|
|
|
|
<para>By default, two IFB devices (ifb0 and ifb1) are created. You can
|
|
control that using the numifbs option (e.g., <command>modprobe ifb
|
|
numifbs=1</command>).</para>
|
|
|
|
<para>To create a single IFB when Shorewall starts, place the following
|
|
two commands in <filename>/etc/shorewall/init</filename>:</para>
|
|
|
|
<programlisting><command>modprobe ifb numifbs=1
|
|
ip link set ifb0 up</command></programlisting>
|
|
|
|
<para>Entries in <filename>/etc/shorewall/tcrules</filename> have no
|
|
effect on shaping traffic through an IFB. To allow classification of such
|
|
traffic, the /etc/shorewall/tcfilters file has been added. Entries in that
|
|
file create <ulink url="http://b42.cz/notes/u32_classifier/">u32
|
|
classification rules</ulink>.</para>
|
|
|
|
<section id="tcfilters">
|
|
<title>/etc/shorewall/tcfilters</title>
|
|
|
|
<para>While this file was created to allow shaping of traffic through an
|
|
IFB, the file may be used for general traffic classification as well.
|
|
The file is similar to <ulink
|
|
url="shorewall-tcrules.html">shorewall-tcrules</ulink>(5) with the
|
|
following key exceptions:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>The first match determines the classification, whereas in the
|
|
tcrules file, the last match determines the classification.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>ipsets are not supported</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>DNS Names are not supported</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Address ranges and lists are not supported</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Exclusion is not supported.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>filters are applied to packets as they <emphasis>appear on the
|
|
wire</emphasis>. So incoming packets will not have DNAT applied yet
|
|
(the destination IP address will be the external address) and
|
|
outgoing packets will have had SNAT applied.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The last point warrants elaboration. When looking at traffic being
|
|
shaped by an IFB, there are two cases to consider:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>Requests — packets being sent from remote clients to local
|
|
servers. These packets may undergo subsequent DNAT, either as a
|
|
result of entries in <filename>/etc/shorewall/nat</filename> or as a
|
|
result of DNAT or REDIRECT rules.</para>
|
|
|
|
<para>Example: <filename>/etc/shorewall/rules</filename>:</para>
|
|
|
|
<programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
|
|
# PORT(S) PORT(S) DEST
|
|
DNAT net dmz:192.168.4.5 tcp 80 - 206.124.146.177</programlisting>
|
|
|
|
<para>Requests redirected by this rule will have destination IP
|
|
address 206.124.146.177 and destination port 80.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Responses — packets being sent from remote servers to local
|
|
clients. These packets may undergo subsequent DNAT as a result of
|
|
entries in <filename>/etc/shorewall/nat</filename> or in
|
|
<filename>/etc/shorewall/masq</filename>. The packet's destination
|
|
IP address will be the external address specified in the
|
|
entry.</para>
|
|
|
|
<para>Example:
|
|
<filename>/etc/shorewall/masq</filename>:<programlisting>#INTERFACE SOURCE ADDRESS
|
|
eth0 192.168.1.0/24 206.124.146.179</programlisting></para>
|
|
|
|
<para>HTTP response packets corresponding to requests that fall
|
|
under that rule will have destination IP address 206.124.146.179 and
|
|
<emphasis role="bold">source</emphasis> port 80.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>Beginning with Shorewall 4.4.15, both IPv4 and IPv6 rules can be
|
|
defined in this file. See <ulink
|
|
url="manpages/shorewall-tcfilters.html">shorewall-tcfilters</ulink> (5)
|
|
for details.</para>
|
|
|
|
<para>Columns in the file are as follow. As in all Shorewall
|
|
configuration files, a hyphen ("-") may be used to indicate that no
|
|
value is supplied in the column.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term>CLASS</term>
|
|
|
|
<listitem>
|
|
<para>The interface name or number followed by a colon (":") and
|
|
the class number.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>SOURCE</term>
|
|
|
|
<listitem>
|
|
<para>SOURCE IP address (host or network). DNS names are not
|
|
allowed.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>DEST</term>
|
|
|
|
<listitem>
|
|
<para>DESTINATION IP address (host or network). DNS names are not
|
|
allowed.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>PROTO</term>
|
|
|
|
<listitem>
|
|
<para>Protocol name or number.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>DEST PORT(S)</term>
|
|
|
|
<listitem>
|
|
<para>Comma-separated list of destination port names or numbers.
|
|
May only be specified if the protocol is TCP, UDP, SCTP or ICMP.
|
|
Port ranges are supported except for ICMP.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>SOURCE PORT</term>
|
|
|
|
<listitem>
|
|
<para>Comma-separated list of source port names or numbers. May
|
|
only be specified if the protocol is TCP, UDP or SCTP. Port ranges
|
|
are supported.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>TOS</term>
|
|
|
|
<listitem>
|
|
<para>Specifies the value of the TOS field. The value can be any
|
|
of the following:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para><option>tos-minimize-delay</option></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><option>tos-maximuze-throughput</option></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><option>tos-maximize-reliability</option></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><option>tos-minimize-cost</option></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><option>tos-normal-service</option></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><replaceable>hex-number</replaceable></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><replaceable>hex-number</replaceable>/<replaceable>hex-number</replaceable></para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>The <replaceable>hex-number</replaceable>s must be exactly
|
|
two digits (e.g., 0x04).</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term>LENGTH</term>
|
|
|
|
<listitem>
|
|
<para>Must be a power of 2 between 32 and 8192 inclusive. Packets
|
|
with a total length that is strictly less than the specified value
|
|
will match the rule.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>Example:</para>
|
|
|
|
<para>I've used this configuration on my own firewall. The IFB portion
|
|
is more for test purposes rather than to serve any well-reasoned QOS
|
|
strategy.</para>
|
|
|
|
<para><filename>/etc/shorewall/init</filename>:<programlisting>qt modprobe ifb numifbs=1
|
|
qt ip link set dev ifb0 up</programlisting></para>
|
|
|
|
<para><filename>/etc/shorewall/interfaces</filename>:</para>
|
|
|
|
<programlisting>#ZONE INTERFACE BROADCAST
|
|
- ifb0</programlisting>
|
|
|
|
<para><filename>/etc/shorewall/tcdevices</filename>:</para>
|
|
|
|
<para><programlisting>
|
|
#INTERFACE IN-BANDWITH OUT-BANDWIDTH OPTIONS REDIRECTED
|
|
# INTERFACES
|
|
1:eth0 - 384kbit classify
|
|
2:ifb0 - 1300kbit - eth0</programlisting>
|
|
<filename>/etc/shorewall/tcclasses</filename>:<programlisting>#INTERFACE MARK RATE CEIL PRIORITY OPTIONS
|
|
1:110 - 5*full/10 full 1 tcp-ack,tos-minimize-delay
|
|
1:120 - 2*full/10 6*full/10 2 default
|
|
1:130 - 2*full/10 6*full/10 3
|
|
2:110 - 5*full/10 full 1 tcp-ack,tos-minimize-delay
|
|
2:120 - 2*full/10 6*full/10 2 default
|
|
2:130 - 2*full/10 6*full/10 3</programlisting><filename>/etc/shorewall/tcfilters</filename>:<programlisting>#INTERFACE: SOURCE DEST PROTO DEST SOURCE
|
|
#CLASS PORT(S) PORT(S)
|
|
#
|
|
# OUTGOING TRAFFIC
|
|
#
|
|
1:130 206.124.146.178 - tcp - 49441,49442 #BITTORRENT on wookie
|
|
1:110 206.124.146.178 #wookie
|
|
1:110 206.124.146.179 #SNAT of internal systems
|
|
1:110 206.124.146.180 #Work Laptop
|
|
1:110 - - icmp echo-request,echo-reply
|
|
1:110 - - icmp echo-reply
|
|
1:130 206.124.146.177 - tcp - 873,25 #Bulk Traffic
|
|
#
|
|
# INCOMING TRAFFIC
|
|
#
|
|
2:110 - 206.124.146.178 #Wookie
|
|
2:110 - 206.124.146.179 #SNAT Responses
|
|
2:110 - 206.124.146.180 #Work Laptop
|
|
2:130 - 206.124.146.177 tcp 25 #Incoming Email.</programlisting></para>
|
|
|
|
<para>You can examine the installed filters with the <command>shorewall
|
|
show filters</command> command. What follows shows the output for
|
|
<filename class="devicefile">eth0</filename> with the filters shown
|
|
above. <emphasis role="bold">Bold font</emphasis> are comments
|
|
explaining the rules.<programlisting>gateway:~ # shorewall-lite show filters
|
|
Shorewall Lite 4.1.6 Classifiers at gateway - Fri Mar 21 08:06:47 PDT 2008
|
|
|
|
Device eth1:
|
|
|
|
Device eth2:
|
|
|
|
Device eth0:
|
|
filter parent 1: protocol ip pref 10 u32
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 3:</emphasis> ht divisor 1 <emphasis
|
|
role="bold"> <========= Start of table 3. parses TCP header</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 3</emphasis>::800 order 2048 key ht 3 bkt 0 <emphasis
|
|
role="bold">flowid 1:130</emphasis> (rule hit 102 success 0)
|
|
match 03690000/ffff0000 at nexthdr+0 (success 0 ) <emphasis
|
|
role="bold"> <========= SOURCE PORT 873 goes to class 1:130</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 2:</emphasis> ht divisor 1 <emphasis
|
|
role="bold"> <========= Start of table 2. parses ICMP header</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 2</emphasis>::800 order 2048 key ht 2 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 0 success 0)
|
|
match 08000000/ff000000 at nexthdr+0 (success 0 ) <emphasis
|
|
role="bold"> <========= ICMP Type 8 goes to class 1:110</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 2</emphasis>::801 order 2049 key ht 2 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 0 success 0)
|
|
match 00000000/ff000000 at nexthdr+0 (success 0 ) <emphasis
|
|
role="bold"> <========= ICMP Type 0 goes to class 1:110</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 1:</emphasis> ht divisor 1 <emphasis
|
|
role="bold"> <========= Start of table 1. parses TCP header</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 1:</emphasis>:800 order 2048 key ht 1 bkt 0 <emphasis
|
|
role="bold">flowid 1:130</emphasis> (rule hit 0 success 0)
|
|
match c1210000/ffff0000 at nexthdr+0 (success 0 ) <emphasis
|
|
role="bold"> <========= SOURCE PORT 49441 goes to class 1:130</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 1</emphasis>::801 order 2049 key ht 1 bkt 0 <emphasis
|
|
role="bold">flowid 1:130</emphasis> (rule hit 0 success 0)
|
|
match c1220000/ffff0000 at nexthdr+0 (success 0 ) <emphasis
|
|
role="bold"> <========= SOURCE PORT 49442 goes to class 1:130</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis> ht divisor 1 <emphasis
|
|
role="bold"><========= Start of Table 800. Packets start here!</emphasis>
|
|
|
|
<emphasis role="bold">=============== The following 2 rules are generated by the class definition in /etc/shorewall/classes ==================</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:800 order 2048 key ht 800 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 2204 success 138)
|
|
match 00060000/00ff0000 at 8 (success 396 ) <emphasis
|
|
role="bold"><========= TCP </emphasis>
|
|
match 05000000/0f00ffc0 at 0 (success 250 ) <emphasis
|
|
role="bold"><========= Header length 20 and Packet Length < 64</emphasis>
|
|
match 00100000/00ff0000 at 32 (success 138 ) <emphasis
|
|
role="bold"><========= ACK</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:801 order 2049 key ht 800 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 2066 success 0)
|
|
match 00100000/00100000 at 0 (success 0 ) <emphasis
|
|
role="bold"><========= Minimize-delay</emphasis><emphasis
|
|
role="bold"> goes to class 1:110</emphasis>
|
|
|
|
<emphasis role="bold"> =============== Jump to Table 1 if the matches are met ==================</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:802 order 2050 key ht 800 bkt 0 <emphasis
|
|
role="bold">link 1:</emphasis> (rule hit 2066 success 0)
|
|
match ce7c92b2/ffffffff at 12 (success 1039 ) <emphasis
|
|
role="bold"><========= SOURCE 206.124.146.178 </emphasis>
|
|
match 00060000/00ff0000 at 8 (success 0 ) <emphasis
|
|
role="bold"><========= PROTO TCP</emphasis>
|
|
offset 0f00>>6 at 0 eat
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:803 order 2051 key ht 800 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 2066 success 1039)
|
|
match ce7c92b2/ffffffff at 12 (success 1039 ) <emphasis
|
|
role="bold"><========= SOURCE 206.124.146.178 goes to class 1:110</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:804 order 2052 key ht 800 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 1027 success 132)
|
|
match ce7c92b3/ffffffff at 12 (success 132 ) <emphasis
|
|
role="bold"> <========= SOURCE 206.124.146.179 goes to class 1:110</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:805 order 2053 key ht 800 bkt 0 <emphasis
|
|
role="bold">flowid 1:110</emphasis> (rule hit 895 success 603)
|
|
match ce7c92b4/ffffffff at 12 (success 603 ) <emphasis
|
|
role="bold"><========= SOURCE 206.124.146.180 goes to class 1:110</emphasis>
|
|
|
|
<emphasis role="bold"> =============== Jump to Table 2 if the matches are met ==================</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:806 order 2054 key ht 800 bkt 0 <emphasis
|
|
role="bold">link 2:</emphasis> (rule hit 292 success 0)
|
|
match 00010000/00ff0000 at 8 (success 0 ) <emphasis
|
|
role="bold"><========= PROTO ICMP</emphasis>
|
|
offset 0f00>>6 at 0 eat
|
|
|
|
<emphasis role="bold"> =============== Jump to Table 3 if the matches are met ==================</emphasis>
|
|
|
|
filter parent 1: protocol ip pref 10 u32 <emphasis role="bold">fh 800:</emphasis>:807 order 2055 key ht 800 bkt 0 <emphasis
|
|
role="bold">link 3:</emphasis> (rule hit 292 success 0)
|
|
match ce7c92b1/ffffffff at 12 (success 265 ) <emphasis
|
|
role="bold"><========= SOURCE 206.124.146.177</emphasis>
|
|
match 00060000/00ff0000 at 8 (success 102 ) <emphasis
|
|
role="bold"><========= PROTO TCP</emphasis>
|
|
offset 0f00>>6 at 0 eat </programlisting></para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="show">
|
|
<title>Understanding the output of 'shorewall show tc'</title>
|
|
|
|
<para>The <command>shorewall show tc</command> (<command>shorewall-lite
|
|
show tc</command>) command displays information about the current state of
|
|
traffic shaping. For each device, it executes the following
|
|
commands:</para>
|
|
|
|
<programlisting> echo Device $device:
|
|
tc -s -d qdisc show dev $device
|
|
echo
|
|
tc -s -d class show dev $device
|
|
echo </programlisting>
|
|
|
|
<para>So, the traffic-shaping output is generated entirely by the
|
|
<command>tc</command> utility.</para>
|
|
|
|
<para>Here's the output of for eth0. The configuration is the one shown in
|
|
the preceding section (the output was obtained almost 24 hours later than
|
|
the <command>shorewall show filters</command> output shown above).</para>
|
|
|
|
<programlisting>Device eth0:
|
|
|
|
<emphasis role="bold"> ============== The primary queuing discipline is HTB (Hierarchical Token Bucket) ==================== </emphasis>
|
|
|
|
qdisc htb 1: r2q 10 default 120 direct_packets_stat 9 ver 3.17
|
|
Sent 2133336743 bytes 4484781 pkt (dropped 198, overlimits 4911403 requeues 21) <emphasis
|
|
role="bold"><=========== Note the overlimits and dropped counts</emphasis>
|
|
rate 0bit 0pps backlog 0b 8p requeues 21
|
|
|
|
<emphasis role="bold">============== The ingress filter. If you specify IN-BANDWIDTH, you can see the 'dropped' count here. =========</emphasis>
|
|
|
|
<emphasis role="bold">In this case, the packets are being sent to the IFB for shaping</emphasis>
|
|
|
|
qdisc ingress ffff: ----------------
|
|
Sent 4069015112 bytes 4997252 pkt (dropped 0, overlimits 0 requeues 0)
|
|
rate 0bit 0pps backlog 0b 0p requeues 0
|
|
|
|
<emphasis role="bold">============ Each of the leaf HTB classes has an SFQ qdisc to ensure that each flow gets its turn ============</emphasis>
|
|
|
|
qdisc sfq 110: parent 1:110 limit 128p quantum 1514b flows 128/1024 perturb 10sec
|
|
Sent 613372519 bytes 2870225 pkt (dropped 0, overlimits 0 requeues 6)
|
|
rate 0bit 0pps backlog 0b 0p requeues 6
|
|
qdisc sfq 120: parent 1:120 limit 128p quantum 1514b flows 128/1024 perturb 10sec
|
|
Sent 18434920 bytes 60961 pkt (dropped 0, overlimits 0 requeues 0)
|
|
rate 0bit 0pps backlog 0b 0p requeues 0
|
|
qdisc sfq 130: parent 1:130 limit 128p quantum 1514b flows 128/1024 perturb 10sec
|
|
Sent 1501528722 bytes 1553586 pkt (dropped 198, overlimits 0 requeues 15)
|
|
rate 0bit 0pps backlog 11706b 8p requeues 15
|
|
|
|
<emphasis role="bold">============= Class 1:110 -- the high-priority class ===========
|
|
|
|
|
|
Note the rate and ceiling calculated from 'full'</emphasis>
|
|
|
|
class htb <emphasis role="bold">1:110</emphasis> parent 1:1 leaf 110: prio 1 quantum 4800 <emphasis
|
|
role="bold">rate 192000bit ceil 384000bit</emphasis> burst 1695b/8 mpu 0b overhead 0b cburst 1791b/8 mpu 0b overhead 0b level 0
|
|
Sent 613372519 bytes 2870225 pkt (dropped 0, overlimits 0 requeues 0)
|
|
<emphasis role="bold">rate 195672bit 28pps backlog 0b 0p</emphasis> requeues 0 <emphasis
|
|
role="bold"><=========== Note the current rate of traffic. There is no queuing (no packet backlog)</emphasis>
|
|
lended: 2758458 borrowed: 111773 giants:
|
|
tokens: 46263 ctokens: 35157
|
|
|
|
<emphasis role="bold">============== The root class ============</emphasis>
|
|
|
|
class htb <emphasis role="bold">1:1 root</emphasis> rate 384000bit ceil 384000bit burst 1791b/8 mpu 0b overhead 0b cburst 1791b/8 mpu 0b overhead 0b level 7
|
|
<emphasis role="bold">Sent 2133276316 bytes 4484785 pkt</emphasis> (dropped 0, overlimits 0 requeues 0) <emphasis
|
|
role="bold"><==== Total output traffic since last 'restart'</emphasis>
|
|
rate 363240bit 45pps backlog 0b 0p requeues 0
|
|
lended: 1081936 borrowed: 0 giants: 0
|
|
tokens: -52226 ctokens: -52226
|
|
|
|
<emphasis role="bold">============= Bulk Class (outgoing rsync, email and bittorrent) ============</emphasis>
|
|
|
|
class htb 1:130 parent 1:1 leaf 130: prio 3 quantum 1900 rate 76000bit ceil 230000bit burst 1637b/8 mpu 0b overhead 0b cburst 1714b/8 mpu 0b overhead 0b level 0
|
|
Sent 1501528722 bytes 1553586 pkt (dropped 198, overlimits 0 requeues 0)
|
|
<emphasis role="bold">rate 162528bit 14pps backlog 0b 8p</emphasis> requeues 0 <emphasis
|
|
role="bold"><======== Queuing is occurring (8 packet backlog). The rate is still below the ceiling.</emphasis>
|
|
lended: 587134 borrowed: 966459 giants: 0 <emphasis role="bold">During peak activity, the rate tops out at around 231000 (just above ceiling).</emphasis>
|
|
tokens: -30919 ctokens: -97657
|
|
|
|
<emphasis role="bold">================= Default class (mostly serving web pages) ===============</emphasis>
|
|
|
|
class htb 1:120 parent 1:1 leaf 120: prio 2 quantum 1900 rate 76000bit ceil 230000bit burst 1637b/8 mpu 0b overhead 0b cburst 1714b/8 mpu 0b overhead 0b level 0
|
|
Sent 18434920 bytes 60961 pkt (dropped 0, overlimits 0 requeues 0)
|
|
rate 2240bit 2pps backlog 0b 0p requeues 0
|
|
lended: 57257 borrowed: 3704 giants: 0
|
|
tokens: 156045 ctokens: 54178
|
|
|
|
</programlisting>
|
|
</section>
|
|
|
|
<section id="External">
|
|
<title id="tcstart">Using your own tc script</title>
|
|
|
|
<section id="owntcstart">
|
|
<title>Replacing builtin tcstart file</title>
|
|
|
|
<para>If you prefer your own tcstart file, just install it in
|
|
/etc/shorewall/tcstart.</para>
|
|
|
|
<para>In your tcstart script, when you want to run the <quote>tc</quote>
|
|
utility, use the run_tc function supplied by Shorewall if you want tc
|
|
errors to stop the firewall.</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>Set TC_ENABLED=Yes and CLEAR_TC=Yes</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Supply an /etc/shorewall/tcstart script to configure your
|
|
traffic shaping rules.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Optionally supply an /etc/shorewall/tcclear script to stop
|
|
traffic shaping. That is usually unnecessary.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>If your tcstart script uses the <quote>fwmark</quote>
|
|
classifier, you can mark packets using entries in
|
|
/etc/shorewall/tcrules.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</section>
|
|
|
|
<section id="Start">
|
|
<title>Traffic control outside Shorewall</title>
|
|
|
|
<para>To start traffic shaping when you bring up your network
|
|
interfaces, you will have to arrange for your traffic shaping
|
|
configuration script to be run at that time. How you do that is
|
|
distribution dependent and will not be covered here. You then
|
|
should:</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>Set TC_ENABLED=No and CLEAR_TC=No</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>If your script uses the <quote>fwmark</quote> classifier, you
|
|
can mark packets using entries in /etc/shorewall/tcrules.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
</section>
|
|
</section>
|
|
|
|
<section id="Testing">
|
|
<title>Testing Tools</title>
|
|
|
|
<para>At least one Shorewall user has found this tool helpful: <ulink
|
|
url="http://e2epi.internet2.edu/network-performance-toolkit.html">http://e2epi.internet2.edu/network-performance-toolkit.html</ulink></para>
|
|
</section>
|
|
</article>
|