Merged from trunk

[thirdparty/squid.git] / doc / release-notes / release-3.4.sgml

<!doctype linuxdoc system>
<article>
<title>Squid 3.4.0.2 release notes</title>
<author>Squid Developers</author>

<abstract>
This document contains the release notes for version 3.4 of Squid.
Squid is a WWW Cache application developed by the National Laboratory
for Applied Network Research and members of the Web Caching community.
</abstract>

<toc>

<sect>Notice
<p>
The Squid Team are pleased to announce the release of Squid-3.4.0.2 for testing.

This new release is available for download from <url url="http://www.squid-cache.org/Versions/v3/3.4/"> or the
 <url url="http://www.squid-cache.org/Mirrors/http-mirrors.html" name="mirrors">.

While this release is not deemed ready for production use, we believe it is ready for wider testing by the community.

We welcome feedback and bug reports. If you find a bug, please see <url url="http://wiki.squid-cache.org/SquidFaq/BugReporting">
 for how to submit a report with a stack trace.

<sect1>Known issues
<p>
Although this release is deemed good enough for use in many setups, please note the existence of 
<url url="http://bugs.squid-cache.org/buglist.cgi?query_format=advanced&amp;product=Squid&amp;bug_status=UNCONFIRMED&amp;bug_status=NEW&amp;bug_status=ASSIGNED&amp;bug_status=REOPENED&amp;version=3.4" name="open bugs against Squid-3.4">.


<sect1>Changes since earlier releases of Squid-3.4
<p>
The 3.4 change history can be <url url="http://www.squid-cache.org/Versions/v3/3.4/changesets/" name="viewed here">.

<sect>Major new features since Squid-3.3
<p>Squid 3.4 represents a new feature release above 3.3.

<p>The most important of these new features are:
<itemize>
        <item>Helper protocol extensions
        <item>SSL Server Certificate Validator
        <item>Store-ID
        <item>TPROXY Support for OpenBSD 5.1+ and FreeBSD 9+
        <item>Transaction Annotations
        <item>Multicast DNS
</itemize>

Most user-facing changes are reflected in squid.conf (see below).


<sect1>Helper protocol extensions
<p>Details at <url url="http://wiki.squid-cache.org/Features/AddonHelpers">.

<p>The Squid helper protocol used to communicate with authenticators,
   URL-rewriters, Redirectors, and External ACL helpers has been updated
   and extended.

<p><em>BH</em> status code is now accepted from all helpers to report
   internal error events separate from <em>ERR</em> rejection code.
   Permitting Squid to perform recovery operations specific to
   helper failure instead of a blanket client rejection.

<p>Arbitrary key-value pairs can be returned from any helper.
   Allowing future helpers to be forward- and backward- compatible
   with this and future version of Squid.


<sect1>SSL Server Certificate Validator
<p>Details at <url url="http://wiki.squid-cache.org/Features/SslServerCertValidator">.

<p>The helper consulted after the internal OpenSSL validation, regardless of the
   validation results. The helper will receive:

<itemize>
        <item>the origin server certificate (chain),
        <item>the intended domain name, and
        <item>a list of OpenSSL validation errors (if any).
</itemize>

<p>If the helper decides to honor an OpenSSL error or report another validation 
   error(s), the helper will return:

<itemize>
        <item>A list of certificates.
        <item>A list of items consists the the validation error name (see <em>%err_name</em>
        error page macro and <em>%err_details</em> code for <em>logformat</em>), error reason
        (<em>%ssl_lib_error macro</em>), and the offending certificate.
</itemize>

<p>The returned information mimics what the internal OpenSSL-based validation code
   collects now. Returned errors, if any, are fed to <em>sslproxy_cert_error</em>,
   triggering the existing SSL error processing code.

<p>The helper invocation controlled by the <em>sslcrtvalidator_program</em> and
   <em>sslcrtvalidator_children</em> configurations options which are similar to the
   <em>ssl_crtd</em> related options. 


<sect1>Store-ID
<p>Details at <url url="http://wiki.squid-cache.org/Features/StoreID">.

<p>This feature is a redesigned equivalent to the Squid-2.7 feature known as StoreURL-rewrite.

<p><em>Notice</em> that this is not a direct portage of the Squid-2.7 feature so behaviour
  differences do exist. Although the new feature works in similar enough ways that the old
  helper scripts used for Squid-2.7 are expected to work in this and later versions of Squid.

<p>Squid traditionally uses the requested URL as an index key ID to locate objects in cache.
   It is not the only key possible and the Store-ID feature exposes an API for external
   helpers to provide Squid with an alternative key name for any URL.

<p>When any client request is received which requires a cache lookup the URL is passed to
   a helper specified with the <em>store_id_program</em> directive to check for an alternative
   Store ID. This allows the helper to identify URLs which refer to duplicate resources and
   de-duplicate the cache content. <em>store_id_access</em> is provided to allow ACL-based
   tuning of which traffic gets sent to the helper and reduce overheads.

<p>One subtle and noteworthy difference between Squid-2 and Squid-3 which is highlighted by
   this feature is that <em>refresh_pattern</em> applies its regex argument against the Store
   ID key and not the transaction URL. So using the Store-ID feature to alter the value
   affects which <em>refresh_pattern</em> directive will be matched.

<p>Store-ID helpers bundled with Squid can be built with the --enable-storeid-rewrite-helpers
   options which is added in this version. Currently there is a <em>file</em> helper
   provided.


<sect1>TPROXY Support for OpenBSD 5.1+ and FreeBSD 9+
<p>Details at <url url="http://wiki.squid-cache.org/ConfigExamples/Intercept/OpenBsdPf">.

<p>The Packet Filter (PF) firewall in OpenBSD 4.4 and later offers traffic interception
   using several very simple methods. One of which is the <em>divert-to</em> rule type
   which acts as a simple routing diversion instead of performing NAT packet alterations.

<p>The IP Firewall (IPFW) on FreeBSD 9+ contains a port of the Linux Netfilter TPROXY feature.

<p>This version of Squid adds support for these features through the ./configure
   options --enable-pf-transparent and --enable-ipfw-transparent when Squid is built on
   systems with the required support. No special extras are required to enable
   <em>http_port ... tproxy</em> configuration to work.

<p>NOTE: To resolve NAT lookup issues on recent PF firewall versions the code behind
   <em>./configure --enable-pf-transparent</em> has been altered and is expected to
   break on the version of PF firewall shipped with BSD systems such as NetBSD and FreeBSD
   which do not yet support the getsockname() API.
   These systems require <em>--with-nat-devpf</em> to enable /dev/pf support when using PF firewall.


<sect1>Transaction Annotations
<p>Previously the only annotation methods available were ICAP/eCAP HTTP header insertions
   or external ACL <em>tag=</em> result code. Each of which had only limited possibilities
   for use and little or no correlation.

<p>It is now possible to add annotations to a client transaction from several sources:
<itemize>
        <item>  Directly from squid.conf using the <em>note</em> directive with
                ACL-based selection of which annotation is linked to any
                particular transaction.

        <item>  By configured helper processes returning a key=value pair.
                The key name becomes the annotation name.
</itemize>

<p>Annotations on the transaction can be passed to ICAP services or eCAP modules using the
   <em>adaptation_meta</em> directive to send them as headers.
   They can also be logged using the <em>%note</em> log format code in custom logs. With
   the new helper response syntax changes this means all helper response key=value details
   such as URL-rewrite or store-id changes, external ACL tag etc. are now able to be logged.

<p>Annotations which are already assigned to a transaction can be checked using an ACL test
   of the new <em>note</em> ACL type. This can match a particular note by name and value,
   of for any notes with a given name.

<p>NOTE: not all helper interfaces are yet enabled to convert key=value into annotations
         and the external ACL interface does not yet send annotations to the helper.


<sect1>Multicast DNS
<p>The internal DNS component of Squid now supports multicast DNS (mDNS) resolution in
    accordance with RFC 6762.

<p>The <em>dns_multicast_local</em> directive must be set to <em>on</em> to enable this
   feature. 

<p>The multicast DNS group IP addresses for IPv4 and IPv6 resolving are added to the set
   of available DNS resolvers and used automatically for domain names ending in <em>.local</em>
   and reverse-DNS lookups before attempting a secondary resolution on the configured
   resolvers. Domains without <em>.local</em> are resolved using only the configured resolvers.

<p>Statistics for multicast DNS resolution can be found on the <em>idns</em> cache manager
   report.


<sect>Changes to squid.conf since Squid-3.3
<p>
There have been changes to Squid's configuration file since Squid-3.3.

<p>Squid supports reading configuration option parameters from external
   files using the syntax <em>parameters("/path/filename")</em>. For example:
<verb>
    acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
</verb>

<p>There hasve also been changes to individual directives in the config file.

This section gives a thorough account of those changes in three categories:

<itemize>
        <item><ref id="newtags" name="New tags">
        <item><ref id="modifiedtags" name="Changes to existing tags">
        <item><ref id="removedtags" name="Removed tags">
</itemize>
<p>

<sect1>New tags<label id="newtags">
<p>
<descrip>
        <tag>configuration_includes_quoted_values</tag>
        <p>Whether Squid supports directive parameters with spaces, quotes, and other
           special characters. Surround such parameters with "double quotes" and
           also set this directive on/off around the relevant squid.conf line(s)
           making use of such quoting.

        <tag>dns_multicast_local</tag>
        <p>Use multicast DNS for <em>.local</em> domains and reverse-DNS resolution.

        <tag>note</tag>
        <p>Use ACLs to annotate a transaction with customized annotations
           which can be logged in access.log

        <tag>spoof_client_ip</tag>
        <p>Access control to determine whether to disable the TPROXY spoofing on upstream traffic.

        <tag>sslcrtvalidator_children</tag>
        <p>Specifies the settings for how many SSL server certificate
           validator helpers are run and when they are started.

        <tag>sslcrtvalidator_program</tag>
        <p>Specifies the location of a SSL server certificate validator helper.

        <tag>store_id_access</tag>
        <p>Whether the URL for a given request is passed to the Store-ID helper process.
           Used to improve StoreID performance by quickly eliminating helper delays using ACL tests.
        <p>Ported equivalent to <em>storeurl_access</em> from 2.7

        <tag>store_id_bypass</tag>
        <p>Whether the StoreID helper may be bypassed when overloaded.

        <tag>store_id_children</tag>
        <p>Controls the number of StoreID helper processes.
        <p>Options <em>startup=N</em>, <em>idle=N</em>, <em>concurrency=N</em>
        <itemize>
                <item>startup=N allow finer tuning of how many helpers are started initially.
                <item>idle=N allow fine tuning of how many helper to retain as buffer against sudden traffic loads.
                <item>concurrency=N was previously called url_rewrite_concurrency as a distinct directive.
        </itemize>

        <tag>storeurl_rewrite_program</tag>
        <p>A helper program to provide cache storage internal key ID value for a request.
        <p>Ported equivalent to <em>storeurl_rewrite_program</em> from 2.7

</descrip>

<sect1>Changes to existing tags<label id="modifiedtags">
<p>
<descrip>
        <tag>access_log</tag>
        <p>Configuration syntax extended to support name=value options.
          <em>New Syntax:</em> access_log module:place [option ...] [acl ...]
        <p>New option <em>logformat=</em> to specify the logging format name.
        <p>New option <em>buffer-size=</em> to specify how large the log buffer
           for this log is to be when <em>buffered_logs</em> is enabled.
        <p>New option <em>on-error=</em> to specify what handling is to be done
           if the logging module encounters a non-recoverable error writing logs.
           With the value <em>die</em> (the default) Squid halts operation.
           With the value <em>drop</em> Squid drops log lines and continue running.

        <tag>acl</tag>
        <p>New test type <em>server_cert_fingerprint</em> to match against 
           server SSL certificate fingerprint.
        <p>New test type <em>note</em> to match against transaction annotations
           by name and value, or just by name.
        <p>New test type <em>any-of</em> to match if any one of a set of named ACLs.
        <p>New test type <em>all-of</em> to match against all of a set of named ACLs.

        <tag>auth_param</tag>
        <p>New result code <em>BH</em> to signal helper internal errors
           available in all authentication schemes.
        <p>New key <em>message=</em> for error message details in all authentication schemes.
        <p>New result code <em>OK</em> and key <em>ha1=</em> in Digest authentication.
        <p>New result codes <em>OK</em>, <em>ERR</em> replace result codes <em>AF</em>,
           and <em>NA</em> in NTLM and Negotiate authentication.
        <p>New key <em>token=</em> for NTLM and Negotiate authentication <em>OK</em> responses.
        <p>Details at <url url="http://wiki.squid-cache.org/Features/AddonHelpers">.

        <tag>external_acl_type</tag>
        <p>Deprecated <em>protocol=3.0</em> option. No longer necessary.
        <p>New result code <em>BH</em> to signal helper internal errors
        <p>Details at <url url="http://wiki.squid-cache.org/Features/AddonHelpers">.

        <tag>http_port</tag>
        <p>Support IPv6 for <em>intercept</em> mode. Requires ip6tables support on Linux,
           PF support on OpenBSD and IPFW support on FreeBSD. Squid will no longer complain
           about misconfiguration if IPv6 support is missing, we now rely on the firewall
           tools reporting misconfiguration when the NAT rules are created.
        <p>Support <em>tproxy</em> mode traffic on BSD systems with BINDANY support
           (OpenBSD 5+, FreeBSD 9+ so far).
        <p>Changed build options behind <em>intercept</em> traffic mode handling on BSD.
           see <em>--enable-pf-transparent</em> for more details.

        <tag>logformat</tag>
        <p>New format code <em>%note</em> to log a transaction annotation linked to the
           transaction by ICAP, eCAP, a helper, or the <em>note</em> squid.conf directive.
        <p>New format code <em>%&gt;qos</em> to log client connection TOS/DSCP value set by Squid.
        <p>New format code <em>%&lt;qos</em> to log server connection TOS/DSCP value set by Squid.
        <p>New format code <em>%&gt;nfmark</em> to log client connection netfilter mark set by Squid.
        <p>New format code <em>%&lt;nfmark</em> to log server connection netfilter mark set by Squid.

        <tag>pipeline_prefetch</tag>
        <p>Updated to take a numeric count of prefetched pipeline requests instead of ON/OFF.

        <tag>refresh_pattern</tag>
        <p><em>NOTE:</em> the regular expression pattern operates on the cache Store-ID value.
           Which by default is identical to the requested URL, but may differ for some
           objects if the Store-ID feature is in use.

        <tag>unlinkd_program</tag>
        <p>New helper response format utilizing result codes <em>OK</em> and <em>BH</em>,
           to signal helper lookup results. Also, key-value response values to return
           multiple values to Squid.
        <p>Details at <url url="http://wiki.squid-cache.org/Features/AddonHelpers">.

        <tag>url_rewrite_program</tag>
        <p>New helper response format utilizing result codes <em>OK</em>, <em>ERR</em>,
           and <em>BH</em> to signal helper lookup results. Also, key-value response
           values to return multiple values to Squid.
        <p>Details at <url url="http://wiki.squid-cache.org/Features/AddonHelpers">.

</descrip>

<sect1>Removed tags<label id="removedtags">
<p>
<descrip>
        <tag>storeurl_access</tag>
        <p>Replaced by <em>store_id_access</em>.

        <tag>storeurl_rewrite_children</tag>
        <p>Replaced by <em>store_id_children</em>.

        <tag>storeurl_rewrite_concurrency</tag>
        <p>Replaced by <em>store_id_children</em> with <em>concurrency=N</em> option.

        <tag>storeurl_rewrite_program</tag>
        <p>Replaced by <em>store_id_program</em>.
        
</descrip>


<sect>Changes to ./configure options since Squid-3.3
<p>
There have been some changes to Squid's build configuration since Squid-3.3.

This section gives an account of those changes in three categories:

<itemize>
        <item><ref id="newoptions" name="New options">
        <item><ref id="modifiedoptions" name="Changes to existing options">
        <item><ref id="removedoptions" name="Removed options">
</itemize>


<sect1>New options<label id="newoptions">
<p>
<descrip>
        <tag>--enable-storeid-rewrite-helpers</tag>
        <p>New option to control which Store-ID helpers are built. As with other
           helper options use --disable-* to prevent any helpers building and
           omit to get all helper auto-detected.
        <p>Currenly only a helper using <em>file</em> for backend is provided.

        <tag>--disable-arch-native</tag>
        <p>New option to disable use of -march=native compiler flag.
        <p>The new flag auto-enables CPU-specific optimizations in GCC and is
          required by Clang++ v3.2 for correct 64-bit environment detection.
          It does not always work well however, so this build option is provided
          to remove it when necessary.

        <tag>--with-nat-devpf</tag>
        <p>New option to alter the behaviour of <em>http_port ... intercept</em> option
           in squid.conf.
        <p>When this option is used Squid performs the /dev/pf lookups required to
           support PF <em>rdr-to</em> rules. Otherwise Squid will perform perform the
           getsockname() API calls to support PF <em>divert-to</em> rules.
        <p>NOTE: systems such as NetBSD and FreeBSD which do not yet support
           the getsockname() API in recent PF versions require this option.

</descrip>

<sect1>Changes to existing options<label id="modifiedoptions">
<p>
<descrip>
        <tag>--enable-pf-transparent</tag>
        <p>NAT table support updated to use the getsockname() API provided by the
           latest PF versions <em>divert-to</em>. This allows <em>http_port</em>
           in squid.conf to support both <em>intercept</em> and <em>tproxy</em> traffic
           and to silence NAT lookup failure messages on recent BSD.
        <p>NOTE: systems such as NetBSD and FreeBSD which do not yet support
           the getsockname() API in recent PF versions require <em>--with-nat-devpf</em>
           to re-enable /dev/pf support when using PF firewall.

</descrip>
</p>

<sect1>Removed options<label id="removedoptions">
<p>
<descrip>
        <p><em>There are no removed ./configure options in Squid-3.4.</em>

</descrip>


<sect>Regressions since Squid-2.7

<p>Some squid.conf options which were available in Squid-2.7 are not yet available in Squid-3.4

<p>If you need something to do then porting one of these from Squid-2 to Squid-3 is most welcome.

<sect1>Missing squid.conf options available in Squid-2.7
<p>
<descrip>
        <tag>broken_vary_encoding</tag>
        <p>Not yet ported from 2.6

        <tag>cache_dir</tag>
        <p><em>COSS</em> storage type is lacking stability fixes from 2.6
        <p>COSS <em>overwrite-percent=</em> option not yet ported from 2.6
        <p>COSS <em>max-stripe-waste=</em> option not yet ported from 2.6
        <p>COSS <em>membufs=</em> option not yet ported from 2.6
        <p>COSS <em>maxfullbufs=</em> option not yet ported from 2.6

        <tag>cache_peer</tag>
        <p><em>idle=</em> not yet ported from 2.7
        <p><em>monitorinterval=</em> not yet ported from 2.6
        <p><em>monitorsize=</em> not yet ported from 2.6
        <p><em>monitortimeout=</em> not yet ported from 2.6
        <p><em>monitorurl=</em> not yet ported from 2.6

        <tag>cache_vary</tag>
        <p>Not yet ported from 2.6

        <tag>collapsed_forwarding</tag>
        <p>Not yet ported from 2.6

        <tag>error_map</tag>
        <p>Not yet ported from 2.6

        <tag>external_refresh_check</tag>
        <p>Not yet ported from 2.7

        <tag>ignore_ims_on_miss</tag>
        <p>Not yet ported from 2.7

        <tag>location_rewrite_access</tag>
        <p>Not yet ported from 2.6

        <tag>location_rewrite_children</tag>
        <p>Not yet ported from 2.6

        <tag>location_rewrite_concurrency</tag>
        <p>Not yet ported from 2.6

        <tag>location_rewrite_program</tag>
        <p>Not yet ported from 2.6

        <tag>refresh_pattern</tag>
        <p><em>stale-while-revalidate=</em> not yet ported from 2.7
        <p><em>ignore-stale-while-revalidate=</em> not yet ported from 2.7
        <p><em>negative-ttl=</em> not yet ported from 2.7

        <tag>refresh_stale_hit</tag>
        <p>Not yet ported from 2.7

        <tag>update_headers</tag>
        <p>Not yet ported from 2.7

</descrip>

</article>