# Squid 3.5.0.0 release notes

## Squid Developers

This document contains the release notes for version 3.5 of Squid. Squid is a WWW Cache application developed by the National Laboratory for Applied Network Research and members of the Web Caching community.

## 1. Notice

- 1.1 Known issues
- 1.2 Changes since earlier releases of Squid-3.5
- 1.3 Copyright disclaimer adjustments

## 2. Major new features since Squid-3.4

- 2.1 Support libecap v1.0
- 2.2 Authentication helper query extensions
- 2.3 Support named services
- 2.4 Upgraded squidclient tool
- 2.5 Helper support for concurrency channels
- 2.6 Native FTP Relay
- 2.7 Receive PROXY protocol, Versions 1 & 2

## 3. Changes to squid.conf since Squid-3.4

- 3.1 New tags
- 3.2 Changes to existing tags
- 3.3 Removed tags

## 4. Changes to ./configure options since Squid-3.4

- 4.1 New options
- 4.2 Changes to existing options
- 4.3 Removed options

## 5. Regressions since Squid-2.7

- 5.1 Missing squid.conf options available in Squid-2.7

## 1. Notice

The Squid Team are pleased to announce the release of Squid-3.5.0.0 for testing.

This new release is available for download from http://www.squid-cache.org/Versions/v3/3.5/ or the 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 http://wiki.squid-cache.org/SquidFaq/BugReporting for how to submit a report with a stack trace.

## 1.1 Known issues

Although this release is deemed good enough for use in many setups, please note the existence of open bugs against Squid-3.5.

## 1.2 Changes since earlier releases of Squid-3.5

The 3.5 change history can be viewed here.

## 1.3 Copyright disclaimer adjustments

Squid sources are now administered by the Squid Software Foundation on behalf of the Squid Project and community.

This version of Squid contains initial changes to streamline copyright declarations in Squid sources and related metafiles. No functionality or licensing changes are intended.

Once completed, the changes will consistently declare Squid contributors (listed in CONTRIBUTORS and represented by the Squid Software Foundation) as Squid copyright owners while referring the reader to the COPYING file for GPL licensing details. The boilerplate with the above information is provided.

These changes do not affect copyright rights of individuals or organizations. We are simply confirming the fact that there are many Squid copyright owners, just like there are many Linux kernel copyright owners. We are also providing a simple, consistent way to document that fact.

## 2. Major new features since Squid-3.4

Squid 3.5 represents a new feature release above 3.4.

The most important of these new features are:

- Support libecap v1.0
- Authentication helper query extensions
- Support named services
- Upgraded squidclient tool
- Helper support for concurrency channels
- Native FTP Relay
- Receive PROXY protocol, Versions 1 & 2

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

## 2.1 Support libecap v1.0

Details at http://wiki.squid-cache.org/Features/BLAH.

The new libecap version allows Squid to better check the version of the eCAP adapter being loaded as well as the version of the eCAP library being used.

Squid-3.5 can support eCAP adapters built with libecap v1.0, but no longer supports adapters built with earlier libecap versions due to API changes.

## 2.2 Authentication helper query extensions

Details at http://www.squid-cache.org/Doc/config/auth_param/.

The new key_extras parameter allows sending of additional details to the authentication helper beyond the minimum required for the HTTP authentication. This is primarily intended to allow switching of authentication databases based on criteria such as client IP subnet, Squid receiving port, or in reverse-proxy the requested domain name.

In theory any logformat code may be used, however only the codes which have available details at the time of authentication will send any meaningful detail.

## 2.3 Support named services

Details at http://wiki.squid-cache.org/MultipleInstances.

Terminology details at http://wiki.squid-cache.org/Features/SmpScale#Terminology.

The command line option -n assigns a name to the Squid service instance to be used as a unique identifier for all SMP processes run as part of that instance. This allows multiple instances of Squid service to be run on a single machine without background SMP systems such as shared memory and inter-process communication becoming confused or requiring additional configuration.

A service name is always used. When the -n option is missing from the command line the default service name is squid.

When multiple instances are being run the -n service name is required to target all other options such as -z or -k commands at the correct service.

The squid.conf macro ${service_name} is added to provide the service name of the process parsing the config.

## 2.4 Upgraded squidclient tool

The squidclient has begun the process of upgrading to support protocols other than HTTP.

### Debug levels

The tool displays the server response message on STDOUT unless the -q command line option is used. Error messages will be output to STDERR. All other possible output is considered debug and output to STDERR using a range of debug verbosity levels (currently 1, 2 and 3).

When the -v command line option is used debugging is enabled. The level of debug display is raised for each repetition of the option.

### PING

When --ping is given the tool will send its message repeatedly using whichever protocol that message has been formatted for. Optional parameters to limit the number of pings and their frequency are available.

Older tool versions also provide this feature but require the loop count parameter to be set to enable use of the feature.

### HTTPS

When Squid is built with the GnuTLS encryption library the tool is able to open TLS (or SSL/3.0) connections to servers.

The --https option enables TLS using default values.

The --cert option specifies a file containing X.509 client certificate and private key in PEM format to be loaded for use. Multiple certificates are supported and the option may be used multiple times to load certificates. The default is not to use a client certificate.

The --params option specifies a library specific set of parameters to be sent to the library for configuring the security context. See http://gnutls.org/manual/html_node/Priority-Strings.html for available GnuTLS parameters.

The --trusted-ca option specifies a file in PEM format containing one or more Certificate Authority (CA) certificates used to verify the remote server. This option may be used multiple times to load additional CA certificate lists. The default is not to use any CA, nor trust any server.

Anonymous TLS (using non-authenticated Diffi-Hellman or Elliptic Curve encryption) is available with the --anonymous-tls option. The default is to use X.509 certificate encryption instead.

When performing TLS/SSL server certificates are always verified, the results shown at debug level 3. The encrypted type is displayed at debug level 2 and the connection is used to send and receive the messages regardless of verification results.

## 2.5 Helper support for concurrency channels

Helper concurrency greatly reduces the communication lag between Squid and its helpers allowing faster transaction speeds even on sequential helpers.

The Digest authentication, Store-ID, and URL-rewrite helpers packaged with Squid have been updated to support concurrency channels. They will auto-detect the channel-ID field and will produce the appropriate response format. With these helpers concurrency may now be set to 0 or any higher number as desired.

## 2.6 Native FTP Relay

Details at http://wiki.squid-cache.org/Features/FtpRelay.

Squid is now capable of accepting native FTP commands and relaying native FTP messages between FTP clients and FTP servers. Native FTP commands accepted at ftp_port are internally converted or wrapped into HTTP-like messages. The same happens to Native FTP responses received from FTP origin servers. Those HTTP-like messages are shoveled through regular access control and adaptation layers between the FTP client and the FTP origin server. This allows Squid to examine, adapt, block, and log FTP exchanges. Squid reuses most HTTP mechanisms when shoveling wrapped FTP messages. For example, http_access and adaptation_access directives are used.

FTP Relay is a new, experimental, complex feature that has seen limited production exposure. Some Squid modules (e.g., caching) do not currently work with native FTP proxying, and many features have not even been tested for compatibility. Test well before deploying!

Native FTP proxying differs substantially from proxying HTTP requests with ftp:// URIs because Squid works as an FTP server and receives actual FTP commands (rather than HTTP requests with FTP URLs).

FTP Relay highlights:

- Added ftp_port directive telling Squid to relay native FTP commands.
- Active and passive FTP support on the user-facing side; require passive connections to come from the control connection source IP address.
- IPv6 support (EPSV and, on the user-facing side, EPRT).
- Intelligent adaptation of relayed FTP FEAT responses.
- Relaying of multi-line FTP control responses using various formats.
- Support relaying of FTP MLSD and MLST commands (RFC 3659).
- Several Microsoft FTP server compatibility features.
- ICAP/eCAP support (at individual FTP command/response level).
- Optional "current FTP directory" tracking with the assistance of injected (by Squid) PWD commands (cannot be 100% reliable due to symbolic links and such, but is helpful in some common use cases).
- No caching support -- no reliable Request URIs for that (see above).

## 2.7 Receive PROXY protocol, Versions 1 & 2

More info at http://www.haproxy.org/download/1.5/doc/proxy-protocol.txt

PROXY protocol provides a simple way for proxies and tunnels of any kind to relay the original client source details without having to alter or understand the protocol being relayed on the connection.

Squid currently supports receiving HTTP traffic from a client proxy using this protocol. An http_port which has been configured to receive this protocol may only be used to receive traffic from client software sending in this protocol. HTTP traffic without the PROXY header is not accepted on such a port.

The accel and intercept options are still used to identify the traffic syntax being delivered by the client proxy.

Squid can be configured by adding an http_port with the require-proxy-header mode flag. The proxy_protocol_access must also be configured with src ACLs to whitelist proxies which are trusted to send correct client details.

Forward-proxy traffic from a client proxy: acl frontend src 192.0.2.1 http_port 3128 require-proxy-header proxy_protocol_access allow frontend

Intercepted traffic from a client proxy or tunnel: acl frontend src 192.0.2.2 http_port 3128 intercept require-proxy-header proxy_protocol_access allow frontend

Reverse-proxy traffic from a frontend load balancer sending PROXY protocol: acl frontend src 192.0.2.3 http_port 3128 accel require-proxy-header proxy_protocol_access allow frontend

Known Issue: Use of require-proxy-header on https_port and ftp_port is not supported.

## 3. Changes to squid.conf since Squid-3.4

There have been changes to Squid's configuration file since Squid-3.4.

Squid supports reading configuration option parameters from external files using the syntax parameters("/path/filename"). For example:

        acl whitelist dstdomain parameters("/etc/squid/whitelist.txt")

The squid.conf macro ${service_name} is added to provide the service name of the process parsing the config.

There have also been changes to individual directives in the config file.

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

- New tags
- Changes to existing tags
- Removed tags

## 3.1 New tags

collapsed_forwarding

  Ported from Squid-2 with no configuration or visible behaviour changes. Collapsing of requests is performed across SMP workers.

ftp_client_idle_timeout

  This new configuration directive controls how long Squid should wait for an FTP request on a connection to an ftp_port. Many FTP clients do not deal with idle connection closures well, necessitating a longer default timeout (30 minutes) than client_idle_pconn_timeout used for incoming HTTP requests (2 minutes). The current default may be changed as we get more experience with FTP relaying.

ftp_client_idle_timeout

  New directive controlling how long to wait for an FTP request on a client connection to Squid ftp_port.

ftp_port

  New configuration directive to accept and relay native FTP commands. Typically used for port 21 traffic. By default, native FTP commands are not accepted.

proxy_protocol_access

  New directive to control which clients are permitted to open PROXY protocol connections on a port flagged with require-proxy-header.

send_hit

  New configuration directive to enable/disable sending cached content based on ACL selection. ACL can be based on client request or cached response details.

sslproxy_cert_sign_hash

  New directive to set the hashing algorithm to use when signing generated certificates.

sslproxy_session_cache_size

  New directive which sets the cache size to use for TLS/SSL sessions cache.

sslproxy_session_ttl

  New directive to specify the time in seconds the TLS/SSL session is valid.

store_id_extras

  New directive to send additional lookup parameters to the configured Store-ID helper program. It takes a string which may contain logformat %macros.

  The Store-ID helper input format is now:

               [channel-ID] url [extras]

  The default value for extras is: "%>a/%>A %un %>rm myip=%la myport=%lp"

store_miss

  New configuration directive to enable/disable caching of MISS responses. ACL can be based on any request or response details.

url_rewrite_extras

  New directive to send additional lookup parameters to the configured URL-rewriter/redirector helper program. It takes a string which may contain logformat %macros.

  The url rewrite and redirector helper input format is now:

               [channel-ID] url [extras]

  The default value for extras is: "%>a/%>A %un %>rm myip=%la myport=%lp"

## 3.2 Changes to existing tags

acl

  Deprecated type tag. Use type note with 'tag' key name instead.

  New type adaptation_service to match the name of any icap_service, ecap_service, adaptation_service_set, or adaptation_service_chain that Squid has used (or attempted to use) for the HTTP transaction so far.

  New type at_step to match the current SSL-Bump processing step. Never matches and should not be used outside of ssl_bump.

auth_param

  New parameter key_extras to send additional parameters to the authentication helper.

cache_dir

  New support for larger than 32KB objects in both rock type cache and shared memory cache.

  New slot-size=N option for rock cache to specify the database slot/page size when small slot sizes are desired. The default and maximum slot size is 32KB.

  Removal of old rock cache dir followed by squid -z is required when upgrading from earlier versions of Squid.

  COSS storage type is formally replaced by Rock storage type. COSS storage type and all COSS specific options are removed.

cache_peer

  New standby=N option to retain a set of N open and unused connections to the peer at virtually all times to reduce TCP handshake delays.

  These connections differ from HTTP persistent connections in that they have not been used for HTTP messaging (and may never be). They may be turned into persistent connections after their first use subject to the same keep-alive critera any HTTP connection is checked for.

  Squid-2 option idle= replaced by standby=.

  NOTE that standby connections are started earlier and available in more circumstances than squid-2 idle connections were. They are also spread over all IPs of the peer.

external_acl_type

  New format code %ssl::>sni to send SSL client SNI.

  New format code %ssl::<cert_subject to send SSL server certificate DN.

  New format code %ssl::<cert_issuer to send SSL server certificate issuer DN.

  New response kv-pair clt_conn_tag= to associates a given tag with the client TCP connection.

forward_max_tries

  Default value increased to 25 destinations to allow better contact and IPv4 failover with domains using long lists of IPv6 addresses.

ftp_epsv

  Converted into an Access List with allow/deny value driven by ACLs using Squid standard first line wins matching basis.

  The old values of on and off imply allow all and deny all respectively and are now deprecated. Do not combine use of on/off values with ACL configuration.

http_port

  protocol= option altered to accept protocol version details. Currently supported values are: HTTP, HTTP/1.1, HTTPS, HTTPS/1.1

  New option require-proxy-header to mark ports receiving PROXY protocol version 1 or 2 traffic.

https_port

  protocol= option altered to accept protocol version details. Currently supported values are: HTTP, HTTP/1.1, HTTPS, HTTPS/1.1

logformat

  New format code %credentials to log the client credentials token.

  New format code %ssl::>sni to TLS client SNI sent to Squid.

  New format code %tS to log transaction start time in "seconds.milliseconds" format, similar to the existing access.log "current time" field (%ts.%03tu) which logs the corresponding transaction finish time.

  New format codes %<rs and %>rs to log request URL scheme from client or sent to server/peer respectively.

  New format codes %<rd and %>rd to log request URL domain from client or sent to server/peer respectively.

  New format codes %<rP and %>rP to log request URL port from client or sent to server/peer respectively.

ssl_bump

  Bumping 'modes' redesigned as 'actions' and ACLs evaluated repeatedly in a number of steps.

  Renamed server-first as bump action.

  Renamed none as splice action.

  New actions peek and stare to receive client or server certificate while preserving the ability to later decide between bumping or splicing the connections later.

  New action terminate to close the client and server connections.

url_rewrite_program

  New response kv-pair clt_conn_tag= to associates a given tag with the client TCP connection.

## 3.3 Removed tags

cache_dns_program

  DNS external helper interface has been removed. It was no longer able to provide high performance service and the internal DNS client library with multicast DNS cover all modern use-cases.

dns_children

  DNS external helper interface has been removed.

hierarchy_stoplist

  Removed. The old directive values prohibiting CGI and dynamic content going to cache_peer are no longer relevant.

  The functionality provided by this directive can be configured using always_direct allow if still needed.

## 4. Changes to ./configure options since Squid-3.4

There have been some changes to Squid's build configuration since Squid-3.4.

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

- New options
- Changes to existing options
- Removed options

## 4.1 New options

BUILDCXX=

  Used when cross-compiling Squid.

  The path and name of a compiler for building cf_gen and related tools used in the compile process.

BUILDCXXFLAGS=

  Used when cross-compiling Squid.

  C++ compiler flags used for building cf_gen and related tools used in the compile process.

--without-gnutls

  New option to explicitly disable use of GnuTLS encryption library. Use of this library is auto-enabled if v3.1.5 or later is available.

  It is currently only used by the squidclient tool.

--without-mit-krb5

  New option to explicitly disable use of MIT Kerberos library. Default is to auto-detect and use if possible.

  Only one Kerberos library may be built against.

--without-heimdal-krb5

  New option to explicitly disable use of Hiemdal Kerberos library. Default is to auto-detect and use if possible.

  Only one Kerberos library may be built against.

--without-gnugss

  New option to explicitly disable use of GNU GSSAPI library for Kerberos. Default is to auto-detect and use if possible.

  Only one Kerberos library may be built against.

## 4.2 Changes to existing options

--enable-icap-client

  Deprecated. ICAP client is now auto-enabled. Use --disable-icap-client to disable if you need to.

## 4.3 Removed options

--disable-internal-dns

  DNS external helper interface has been removed. It was no longer able to provide high performance service and the internal DNS client library with multicast DNS cover all modern use-cases.

--enable-ssl

  Removed. Use --with-openssl to enable OpenSSL library support.

--with-coss-membuf-size

  The COSS cache type has been removed. It has been replaced by rock cache type.

--with-krb5-config

  Removed. The Kerberos library is auto-detected now.

  Use --with/--without-mit-krb5, --with/--without-heimdal-krb5, or --with/--without-gnugss options for specific library selection if necesary.

## 5. Regressions since Squid-2.7

Some squid.conf options which were available in Squid-2.7 are not yet available in Squid-3.5

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

## 5.1 Missing squid.conf options available in Squid-2.7

broken_vary_encoding

  Not yet ported from 2.6

cache_peer

  monitorinterval= not yet ported from 2.6

  monitorsize= not yet ported from 2.6

  monitortimeout= not yet ported from 2.6

  monitorurl= not yet ported from 2.6

cache_vary

  Not yet ported from 2.6

error_map

  Not yet ported from 2.6

external_refresh_check

  Not yet ported from 2.7

location_rewrite_access

  Not yet ported from 2.6

location_rewrite_children

  Not yet ported from 2.6

location_rewrite_concurrency

  Not yet ported from 2.6

location_rewrite_program

  Not yet ported from 2.6

refresh_pattern

  stale-while-revalidate= not yet ported from 2.7

  ignore-stale-while-revalidate= not yet ported from 2.7

  negative-ttl= not yet ported from 2.7

refresh_stale_hit

  Not yet ported from 2.7

update_headers

  Not yet ported from 2.7