1 <!doctype linuxdoc system>
3 <title>Squid 3.5.0.2 release notes</title>
4 <author>Squid Developers</author>
7 This document contains the release notes for version 3.5 of Squid.
8 Squid is a WWW Cache application developed by the National Laboratory
9 for Applied Network Research and members of the Web Caching community.
16 The Squid Team are pleased to announce the release of Squid-3.5.0.2 for testing.
18 This new release is available for download from <url url="http://www.squid-cache.org/Versions/v3/3.5/"> or the
19 <url url="http://www.squid-cache.org/Mirrors/http-mirrors.html" name="mirrors">.
21 <p>While this release is not deemed ready for production use, we believe it is ready for wider testing by the community.
23 <p>We welcome feedback and bug reports. If you find a bug, please see <url url="http://wiki.squid-cache.org/SquidFaq/BugReporting">
24 for how to submit a report with a stack trace.
28 Although this release is deemed good enough for use in many setups, please note the existence of
29 <url url="http://bugs.squid-cache.org/buglist.cgi?query_format=advanced&product=Squid&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&version=3.5" name="open bugs against Squid-3.5">.
31 <sect1>Changes since earlier releases of Squid-3.5
33 The 3.5 change history can be <url url="http://www.squid-cache.org/Versions/v3/3.5/changesets/" name="viewed here">.
35 <sect1>Copyright disclaimer adjustments
36 <p>Squid sources are now administered by the Squid Software Foundation on
37 behalf of the Squid Project and community.
39 <p>This version of Squid contains initial changes to streamline copyright
40 declarations in Squid sources and related metafiles. No functionality
41 or licensing changes are intended.
43 <p>Once completed, the changes will consistently declare Squid contributors
44 (listed in CONTRIBUTORS and represented by the Squid Software Foundation) as
45 Squid copyright owners while referring the reader to the COPYING file for GPL
46 licensing details. The boilerplate with the above information is provided.
48 <p>These changes do not affect copyright rights of individuals or organizations.
49 We are simply confirming the fact that there are many Squid copyright owners,
50 just like there are many Linux kernel copyright owners. We are also providing
51 a simple, consistent way to document that fact.
54 <sect>Major new features since Squid-3.4
55 <p>Squid 3.5 represents a new feature release above 3.4.
57 <p>The most important of these new features are:
59 <item>Support libecap v1.0
60 <item>Authentication helper query extensions
61 <item>Support named services
62 <item>Upgraded squidclient tool
63 <item>Helper support for concurrency channels
64 <item>Native FTP Relay
65 <item>Receive PROXY protocol, Versions 1 & 2
68 Most user-facing changes are reflected in squid.conf (see below).
71 <sect1>Support libecap v1.0
72 <p>Details at <url url="http://wiki.squid-cache.org/Features/BLAH">.
74 <p>The new libecap version allows Squid to better check the version of
75 the eCAP adapter being loaded as well as the version of the eCAP library
78 <p>Squid-3.5 can support eCAP adapters built with libecap v1.0,
79 but no longer supports adapters built with earlier libecap versions
83 <sect1>Authentication helper query extensions
84 <p>Details at <url url="http://www.squid-cache.org/Doc/config/auth_param/">.
86 <p>The new <em>key_extras</em> parameter allows sending of additional
87 details to the authentication helper beyond the minimum required for
88 the HTTP authentication. This is primarily intended to allow switching
89 of authentication databases based on criteria such as client IP subnet,
90 Squid receiving port, or in reverse-proxy the requested domain name.
92 <p>In theory any <em>logformat</em> code may be used, however only the
93 codes which have available details at the time of authentication
94 will send any meaningful detail.
97 <sect1>Support named services
98 <p>Details at <url url="http://wiki.squid-cache.org/MultipleInstances">.
99 <p>Terminology details at <url url="http://wiki.squid-cache.org/Features/SmpScale#Terminology">.
101 <p>The command line option <em>-n</em> assigns a name to the Squid service
102 instance to be used as a unique identifier for all SMP processes run as
103 part of that instance. This allows multiple instances of Squid service to
104 be run on a single machine without background SMP systems such as shared
105 memory and inter-process communication becoming confused or requiring
106 additional configuration.
108 <p>A service name is always used. When the <em>-n</em> option is missing
109 from the command line the default service name is <em>squid</em>.
111 <p>When multiple instances are being run the <em>-n</em> service name is
112 required to target all other options such as <em>-z</em> or <em>-k</em>
113 commands at the correct service.
115 <p>The squid.conf macro ${service_name} is added to provide the service name
116 of the process parsing the config.
119 <sect1>Upgraded squidclient tool
120 <p>The <em>squidclient</em> has begun the process of upgrading to support
121 protocols other than HTTP.
124 <p>The tool displays the server response message on STDOUT unless the <em>-q</em>
125 command line option is used. Error messages will be output to STDERR.
126 All other possible output is considered debug and output to STDERR using
127 a range of debug verbosity levels (currently 1, 2 and 3).
129 <p>When the <em>-v</em> command line option is used debugging is enabled.
130 The level of debug display is raised for each repetition of the option.
133 <p>When <em>--ping</em> is given the tool will send its message repeatedly
134 using whichever protocol that message has been formatted for.
135 Optional parameters to limit the number of pings and their frequency are
138 <p>Older tool versions also provide this feature but require the loop count
139 parameter to be set to enable use of the feature.
142 <p>When Squid is built with the GnuTLS encryption library the tool is able
143 to open TLS (or SSL/3.0) connections to servers.
145 <p>The <em>--https</em> option enables TLS using default values.
147 <p>The <em>--cert</em> option specifies a file containing X.509 client
148 certificate and private key in PEM format to be loaded for use. Multiple
149 certificates are supported and the option may be used multiple times to
151 The default is not to use a client certificate.
153 <p>The <em>--params</em> option specifies a library specific set of parameters
154 to be sent to the library for configuring the security context.
155 See <url url="http://gnutls.org/manual/html_node/Priority-Strings.html"> for
156 available GnuTLS parameters.
158 <p>The <em>--trusted-ca</em> option specifies a file in PEM format containing
159 one or more Certificate Authority (CA) certificates used to verify the
160 remote server. This option may be used multiple times to load additional
161 CA certificate lists.
162 The default is not to use any CA, nor trust any server.
164 <p>Anonymous TLS (using non-authenticated Diffi-Hellman or Elliptic Curve
165 encryption) is available with the <em>--anonymous-tls</em> option.
166 The default is to use X.509 certificate encryption instead.
168 <p>When performing TLS/SSL server certificates are always verified, the
169 results shown at debug level 3. The encrypted type is displayed at debug
170 level 2 and the connection is used to send and receive the messages
171 regardless of verification results.
174 <sect1>Helper support for concurrency channels
175 <p>Helper concurrency greatly reduces the communication lag between Squid
176 and its helpers allowing faster transaction speeds even on sequential
179 <p>The Digest authentication, Store-ID, and URL-rewrite helpers packaged
180 with Squid have been updated to support concurrency channels. They will
181 auto-detect the <em>channel-ID</em> field and will produce the appropriate
183 With these helpers concurrency may now be set to 0 or any higher number as desired.
186 <sect1>Native FTP Relay
187 <p>Details at <url url="http://wiki.squid-cache.org/Features/FtpRelay">.
189 <p>Squid is now capable of accepting native FTP commands and relaying native
190 FTP messages between FTP clients and FTP servers. Native FTP commands
191 accepted at ftp_port are internally converted or wrapped into HTTP-like
192 messages. The same happens to Native FTP responses received from FTP origin
193 servers. Those HTTP-like messages are shoveled through regular access
194 control and adaptation layers between the FTP client and the FTP origin
195 server. This allows Squid to examine, adapt, block, and log FTP exchanges.
196 Squid reuses most HTTP mechanisms when shoveling wrapped FTP messages. For
197 example, http_access and adaptation_access directives are used.
199 <p>FTP Relay is a new, experimental, complex feature that has seen limited
200 production exposure. Some Squid modules (e.g., caching) do not currently
201 work with native FTP proxying, and many features have not even been tested
202 for compatibility. Test well before deploying!
204 <p>Native FTP proxying differs substantially from proxying HTTP requests with
205 <em>ftp://</em> URIs because Squid works as an FTP server and receives
206 actual FTP commands (rather than HTTP requests with FTP URLs).
208 <p>FTP Relay highlights:
210 <item>Added ftp_port directive telling Squid to relay native FTP commands.
211 <item>Active and passive FTP support on the user-facing side; require
212 passive connections to come from the control connection source IP
214 <item>IPv6 support (EPSV and, on the user-facing side, EPRT).
215 <item>Intelligent adaptation of relayed FTP FEAT responses.
216 <item>Relaying of multi-line FTP control responses using various formats.
217 <item>Support relaying of FTP MLSD and MLST commands (RFC 3659).
218 <item>Several Microsoft FTP server compatibility features.
219 <item>ICAP/eCAP support (at individual FTP command/response level).
220 <item>Optional "current FTP directory" tracking with the assistance of
221 injected (by Squid) PWD commands (cannot be 100% reliable due to
222 symbolic links and such, but is helpful in some common use cases).
223 <item>No caching support -- no reliable Request URIs for that (see above).
226 <sect1>Receive PROXY protocol, Versions 1 & 2
227 <p>More info at <url url="http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt">
229 <p>PROXY protocol provides a simple way for proxies and tunnels of any kind to
230 relay the original client source details without having to alter or understand
231 the protocol being relayed on the connection.
233 <p>Squid currently supports receiving HTTP traffic from a client proxy using this protocol.
234 An http_port which has been configured to receive this protocol may only be used to
235 receive traffic from client software sending in this protocol.
236 HTTP traffic without the PROXY header is not accepted on such a port.
238 <p>The <em>accel</em> and <em>intercept</em> options are still used to identify the
239 traffic syntax being delivered by the client proxy.
241 <p>Squid can be configured by adding an <em>http_port</em>
242 with the <em>require-proxy-header</em> mode flag. The <em>proxy_protocol_access</em>
243 must also be configured with <em>src</em> ACLs to whitelist proxies which are
244 trusted to send correct client details.
246 <p>Forward-proxy traffic from a client proxy:
248 acl frontend src 192.0.2.1
249 http_port 3128 require-proxy-header
250 proxy_protocol_access allow frontend
253 <p>Intercepted traffic from a client proxy or tunnel:
255 acl frontend src 192.0.2.2
256 http_port 3128 intercept require-proxy-header
257 proxy_protocol_access allow frontend
260 <p>Reverse-proxy traffic from a frontend load balancer sending PROXY protocol:
262 acl frontend src 192.0.2.3
263 http_port 3128 accel require-proxy-header
264 proxy_protocol_access allow frontend
267 <p><em>Known Issue:</em>
268 Use of <em>require-proxy-header</em> on <em>https_port</em> and <em>ftp_port</em> is not supported.
271 <sect>Changes to squid.conf since Squid-3.4
273 There have been changes to Squid's configuration file since Squid-3.4.
275 <p>Squid supports reading configuration option parameters from external
276 files using the syntax <em>parameters("/path/filename")</em>. For example:
278 acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")
281 <p>The squid.conf macro <em>${service_name}</em> is added to provide the service name
282 of the process parsing the config.
284 <p>There have also been changes to individual directives in the config file.
286 This section gives a thorough account of those changes in three categories:
289 <item><ref id="newtags" name="New tags">
290 <item><ref id="modifiedtags" name="Changes to existing tags">
291 <item><ref id="removedtags" name="Removed tags">
295 <sect1>New tags<label id="newtags">
298 <tag>collapsed_forwarding</tag>
299 <p>Ported from Squid-2 with no configuration or visible behaviour changes.
300 Collapsing of requests is performed across SMP workers.
302 <tag>ftp_client_idle_timeout</tag>
303 <p>This new configuration directive controls how long Squid should
304 wait for an FTP request on a connection to an ftp_port. Many FTP
305 clients do not deal with idle connection closures well,
306 necessitating a longer default timeout (30 minutes) than
307 client_idle_pconn_timeout used for incoming HTTP requests (2
308 minutes). The current default may be changed as we get more
309 experience with FTP relaying.
311 <tag>ftp_client_idle_timeout</tag>
312 <p>New directive controlling how long to wait for an FTP request on a
313 client connection to Squid <em>ftp_port</em>.
316 <p>New configuration directive to accept and relay native FTP
317 commands. Typically used for port 21 traffic. By default, native
318 FTP commands are not accepted.
320 <tag>proxy_protocol_access</tag>
321 <p>New directive to control which clients are permitted to open PROXY
322 protocol connections on a port flagged with <em>require-proxy-header</em>.
325 <p>New configuration directive to enable/disable sending cached content
326 based on ACL selection. ACL can be based on client request or cached
329 <tag>sslproxy_cert_sign_hash</tag>
330 <p>New directive to set the hashing algorithm to use when signing generated certificates.
332 <tag>sslproxy_session_cache_size</tag>
333 <p>New directive which sets the cache size to use for TLS/SSL sessions cache.
335 <tag>sslproxy_session_ttl</tag>
336 <p>New directive to specify the time in seconds the TLS/SSL session is valid.
338 <tag>store_id_extras</tag>
339 <p>New directive to send additional lookup parameters to the configured
340 Store-ID helper program. It takes a string which may contain logformat %macros.
341 <p>The Store-ID helper input format is now:
343 [channel-ID] url [extras]
345 <p>The default value for extras is: "%>a/%>A %un %>rm myip=%la myport=%lp"
347 <tag>store_miss</tag>
348 <p>New configuration directive to enable/disable caching of MISS responses.
349 ACL can be based on any request or response details.
351 <tag>url_rewrite_extras</tag>
352 <p>New directive to send additional lookup parameters to the configured
353 URL-rewriter/redirector helper program. It takes a string which may
354 contain logformat %macros.
355 <p>The url rewrite and redirector helper input format is now:
357 [channel-ID] url [extras]
359 <p>The default value for extras is: "%>a/%>A %un %>rm myip=%la myport=%lp"
363 <sect1>Changes to existing tags<label id="modifiedtags">
367 <p>Deprecated type <em>tag</em>. Use type <em>note</em> with 'tag' key
369 <p>New type <em>adaptation_service</em> to match the name of any
370 icap_service, ecap_service, adaptation_service_set, or
371 adaptation_service_chain that Squid has used (or attempted to use)
372 for the HTTP transaction so far.
373 <p>New type <em>at_step</em> to match the current SSL-Bump processing step.
374 Never matches and should not be used outside of <em>ssl_bump</em>.
376 <tag>auth_param</tag>
377 <p>New parameter <em>key_extras</em> to send additional parameters to
378 the authentication helper.
381 <p>New support for larger than 32KB objects in both <em>rock</em> type
382 cache and shared memory cache.
383 <p>New <em>slot-size=N</em> option for rock cache to specify the database
384 slot/page size when small slot sizes are desired. The default and
385 maximum slot size is 32KB.
386 <p>Removal of old rock cache dir followed by <em>squid -z</em> is required
387 when upgrading from earlier versions of Squid.
388 <p><em>COSS</em> storage type is formally replaced by Rock storage type.
389 COSS storage type and all COSS specific options are removed.
391 <tag>cache_peer</tag>
392 <p>New <em>standby=N</em> option to retain a set of N open and unused
393 connections to the peer at virtually all times to reduce TCP handshake
395 <p>These connections differ from HTTP persistent connections in that they
396 have not been used for HTTP messaging (and may never be). They may be
397 turned into persistent connections after their first use subject to the
398 same keep-alive critera any HTTP connection is checked for.
399 <p>Squid-2 option <em>idle=</em> replaced by <em>standby=</em>.
400 <p>NOTE that standby connections are started earlier and available in
401 more circumstances than squid-2 idle connections were. They are
402 also spread over all IPs of the peer.
404 <tag>external_acl_type</tag>
405 <p>New format code <em>%ssl::>sni</em> to send SSL client SNI.
406 <p>New format code <em>%ssl::<cert_subject</em> to send SSL server certificate DN.
407 <p>New format code <em>%ssl::<cert_issuer</em> to send SSL server certificate issuer DN.
408 <p>New response kv-pair <em>clt_conn_tag=</em> to associates a given tag with the client TCP connection.
410 <tag>forward_max_tries</tag>
411 <p>Default value increased to <em>25 destinations</em> to allow better
412 contact and IPv4 failover with domains using long lists of IPv6
416 <p>Converted into an Access List with allow/deny value driven by ACLs
417 using Squid standard first line wins matching basis.
418 <p>The old values of <em>on</em> and <em>off</em> imply <em>allow all</em>
419 and <em>deny all</em> respectively and are now deprecated.
420 Do not combine use of on/off values with ACL configuration.
423 <p><em>protocol=</em> option altered to accept protocol version details.
424 Currently supported values are: HTTP, HTTP/1.1, HTTPS, HTTPS/1.1
425 <p>New option <em>require-proxy-header</em> to mark ports receiving PROXY
426 protocol version 1 or 2 traffic.
428 <tag>https_port</tag>
429 <p><em>protocol=</em> option altered to accept protocol version details.
430 Currently supported values are: HTTP, HTTP/1.1, HTTPS, HTTPS/1.1
433 <p>New format code <em>%credentials</em> to log the client credentials token.
434 <p>New format code <em>%ssl::>sni</em> to TLS client SNI sent to Squid.
435 <p>New format code <em>%tS</em> to log transaction start time in
436 "seconds.milliseconds" format, similar to the existing access.log
437 "current time" field (%ts.%03tu) which logs the corresponding
438 transaction finish time.
439 <p>New format codes <em>%<rs</em> and <em>%>rs</em> to log request URL
440 scheme from client or sent to server/peer respectively.
441 <p>New format codes <em>%<rd</em> and <em>%>rd</em> to log request URL
442 domain from client or sent to server/peer respectively.
443 <p>New format codes <em>%<rP</em> and <em>%>rP</em> to log request URL
444 port from client or sent to server/peer respectively.
447 <p>Bumping 'modes' redesigned as 'actions' and ACLs evaluated repeatedly in a number of steps.
448 <p>Renamed <em>server-first</em> as <em>bump</em> action.
449 <p>Renamed <em>none</em> as <em>splice</em> action.
450 <p>New actions <em>peek</em> and <em>stare</em> to receive client or server
451 certificate while preserving the ability to later decide between bumping
452 or splicing the connections later.
453 <p>New action <em>terminate</em> to close the client and server connections.
455 <tag>url_rewrite_program</tag>
456 <p>New response kv-pair <em>clt_conn_tag=</em> to associates a given tag with the client TCP connection.
460 <sect1>Removed tags<label id="removedtags">
463 <tag>cache_dns_program</tag>
464 <p>DNS external helper interface has been removed. It was no longer
465 able to provide high performance service and the internal DNS
466 client library with multicast DNS cover all modern use-cases.
468 <tag>dns_children</tag>
469 <p>DNS external helper interface has been removed.
471 <tag>hierarchy_stoplist</tag>
472 <p>Removed. The old directive values prohibiting CGI and dynamic content
473 going to cache_peer are no longer relevant.
474 <p>The functionality provided by this directive can be configured
475 using <em>always_direct allow</em> if still needed.
480 <sect>Changes to ./configure options since Squid-3.4
482 There have been some changes to Squid's build configuration since Squid-3.4.
484 This section gives an account of those changes in three categories:
487 <item><ref id="newoptions" name="New options">
488 <item><ref id="modifiedoptions" name="Changes to existing options">
489 <item><ref id="removedoptions" name="Removed options">
493 <sect1>New options<label id="newoptions">
497 <p>Used when cross-compiling Squid.
498 <p>The path and name of a compiler for building cf_gen and related
499 tools used in the compile process.
501 <tag>BUILDCXXFLAGS=</tag>
502 <p>Used when cross-compiling Squid.
503 <p>C++ compiler flags used for building cf_gen and related
504 tools used in the compile process.
506 <tag>--without-gnutls</tag>
507 <p>New option to explicitly disable use of GnuTLS encryption library.
508 Use of this library is auto-enabled if v3.1.5 or later is available.
509 <p>It is currently only used by the squidclient tool.
511 <tag>--without-mit-krb5</tag>
512 <p>New option to explicitly disable use of MIT Kerberos library.
513 Default is to auto-detect and use if possible.
514 <p>Only one Kerberos library may be built against.
516 <tag>--without-heimdal-krb5</tag>
517 <p>New option to explicitly disable use of Hiemdal Kerberos library.
518 Default is to auto-detect and use if possible.
519 <p>Only one Kerberos library may be built against.
521 <tag>--without-gnugss</tag>
522 <p>New option to explicitly disable use of GNU GSSAPI library for Kerberos.
523 Default is to auto-detect and use if possible.
524 <p>Only one Kerberos library may be built against.
528 <sect1>Changes to existing options<label id="modifiedoptions">
531 <tag>--enable-icap-client</tag>
532 <p>Deprecated. ICAP client is now auto-enabled.
533 Use --disable-icap-client to disable if you need to.
538 <sect1>Removed options<label id="removedoptions">
541 <tag>--disable-internal-dns</tag>
542 <p>DNS external helper interface has been removed. It was no longer
543 able to provide high performance service and the internal DNS
544 client library with multicast DNS cover all modern use-cases.
546 <tag>--enable-ssl</tag>
547 <p>Removed. Use <em>--with-openssl</em> to enable OpenSSL library support.
549 <tag>--with-coss-membuf-size</tag>
550 <p>The COSS cache type has been removed.
551 It has been replaced by <em>rock</em> cache type.
553 <tag>--with-krb5-config</tag>
554 <p>Removed. The Kerberos library is auto-detected now.
555 <p>Use <em>--with/--without-mit-krb5</em>, <em>--with/--without-heimdal-krb5</em>, or
556 <em>--with/--without-gnugss</em> options for specific library selection if necesary.
561 <sect>Regressions since Squid-2.7
563 <p>Some squid.conf options which were available in Squid-2.7 are not yet available in Squid-3.5
565 <p>If you need something to do then porting one of these from Squid-2 to Squid-3 is most welcome.
567 <sect1>Missing squid.conf options available in Squid-2.7
570 <tag>broken_vary_encoding</tag>
571 <p>Not yet ported from 2.6
573 <tag>cache_peer</tag>
574 <p><em>monitorinterval=</em> not yet ported from 2.6
575 <p><em>monitorsize=</em> not yet ported from 2.6
576 <p><em>monitortimeout=</em> not yet ported from 2.6
577 <p><em>monitorurl=</em> not yet ported from 2.6
579 <tag>cache_vary</tag>
580 <p>Not yet ported from 2.6
583 <p>Not yet ported from 2.6
585 <tag>external_refresh_check</tag>
586 <p>Not yet ported from 2.7
588 <tag>location_rewrite_access</tag>
589 <p>Not yet ported from 2.6
591 <tag>location_rewrite_children</tag>
592 <p>Not yet ported from 2.6
594 <tag>location_rewrite_concurrency</tag>
595 <p>Not yet ported from 2.6
597 <tag>location_rewrite_program</tag>
598 <p>Not yet ported from 2.6
600 <tag>refresh_pattern</tag>
601 <p><em>stale-while-revalidate=</em> not yet ported from 2.7
602 <p><em>ignore-stale-while-revalidate=</em> not yet ported from 2.7
603 <p><em>negative-ttl=</em> not yet ported from 2.7
605 <tag>refresh_stale_hit</tag>
606 <p>Not yet ported from 2.7
608 <tag>update_headers</tag>
609 <p>Not yet ported from 2.7
615 Copyright (C) 1996-2014 The Squid Software Foundation and contributors
617 Squid software is distributed under GPLv2+ license and includes
618 contributions from numerous individuals and organizations.
619 Please see the COPYING and CONTRIBUTORS files for details.