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ext_time_quota_acl(8)       System Manager's Manual      ext_time_quota_acl(8)

NAME
       ext_time_quota_acl - Squid time quota external acl helper.

       Version 1.0

SYNOPSIS
       ext_time_quota_acl  [-b  database] [-l logfile] [-d] [-p pauselen] [-h]
       configfile

DESCRIPTION
       ext_time_quota_acl allows an administrator to define time  budgets  for
       the users of squid to limit the time using squid.

       This  is  useful for corporate lunch time allocations, wifi portal pay-
       per-minute installations or for parental control of children.  The  ad-
       ministrator can define a time budget (e.g. 1 hour per day) which is en-
       forced through this helper.

OPTIONS
       -b database
              Filename   of   persistent   database.    This    defaults    to
              ext_time_quota.db in Squids state directory.

       -p pauselen
              Pauselen  is given in seconds and defines the period between two
              requests to be treated as part  of  the  same  session.   Pauses
              shorter  than  this  value  will  be  counted against the quota,
              longer ones ignored.  Default is 300 seconds (5 minutes).

       -l logfile
              Filename where all logging and  debugging  information  will  be
              written. If none is given, then stderr will be used and the log-
              ging will go to Squids main cache.log.

       -d     Enables debug logging in the logfile.

       -h     show a short command line help.

       configfile
              This file contains the definition of the time  budgets  for  the
              users.

CONFIGURATION
       The  time  quotas of the users are defined in a text file typically re-
       siding in /etc/squid/time_quota. Any line starting with "#" contains  a
       comment and is ignored. Every line must start with a user followed by a
       time budget and a corresponding time period separated by "/".  Here  is
       an example file:

              # user budget / period
              john 8h / 1d
              littlejoe 1h / 1d
              babymary 30m / 1w

       John  has a time budget of 8 hours every day, littlejoe is only allowed
       1 hour and the poor babymary only 30 minutes a week.

       You can use "s" for seconds, "m" for minutes, "h" for  hours,  "d"  for
       days and "w" for weeks. Numerical values can be given as integer values
       or with a fraction. E.g. "0.5h" means 30 minutes.

       This helper is configured in squid.conf using the external_acl_type di-
       rective then access controls which use it to allow or deny.

       Here is an example.

              # Ensure that users have a valid login. We need their username.
              acl users proxy_auth REQUIRED
              http_access deny !users
              # Define program and quota file
              external_acl_type   time_quota   ttl=60   children-max=1  %LOGIN
              /usr/libexec/ext_time_quota_acl /etc/squid/time_quota
              acl noquota src all
              acl time_quota external time_quota
              deny_info ERR_ACL_TIME_QUOTA_EXCEEDED noquota
              http_access deny !time_quota noquota

       In this example, after restarting Squid it should allow access only for
       users as long as they have time budget left.  If the budget is exceeded
       the user will be presented with an error page informing them.

       In this example we use separate users access control and noquota ACL in
       order  to  keep the username and password prompt and the quota-exceeded
       messages separated.

       User is just a unique key value. The above example uses %LOGIN and  the
       username  but  any  of the external_acl_type format tags can be substi-
       tuted in its place.  %EXT_TAG , %LOGIN , %IDENT , %EXT_USER  ,  %SRC  ,
       %SRCEUI48  , and %SRCEUI64 are all likely candidates for client identi-
       fication.  The Squid  wiki  has  more  examples  at  http://wiki.squid-
       cache.org/ConfigExamples.

LIMITATIONS
       This  helper only controls access to the Internet through HTTP. It does
       not control other protocols, like VOIP, ICQ, IRC, FTP,  IMAP,  SMTP  or
       SSH.

       Desktop browsers are typically able to deal with authentication to HTTP
       proxies like squid .  But more and more different programs and  devices
       (smartphones, games on mobile devices, ...) are using the Internet over
       HTTP. These devices are often not able to work through an  authenticat-
       ing  proxy.  Means other than %LOGIN authentication are required to au-
       thorize these devices and software.

       A more general control to Internet access could be a captive portal ap-
       proach  (such  as  pfSense  or  ChilliSpot)  using  %SRC, %SRCEUI48 and
       %SRCEUI64 as keys or maybe a 802.11X solution. But the latter is  often
       not supported by mobile devices.

IMPLEMENTATION
       When  the  helper is called it will be asked if the current user is al-
       lowed to access squid. The helper will reduce the remaining time budget
       of  this  user and return OK if there is budget left. Otherwise it will
       return ERR .

       The ttl=N parameter in squid.conf determines how often the helper  will
       be  called, the example config uses a 1 minute TTL.  The interaction is
       that Squid will only call the helper on new requests if there has  been
       more  than  TTL seconds passed since last check.  This handling creates
       an amount of slippage outside the quota by whatever amount  is  config-
       ured.   TTL can be set as short as desired, down to and including zero.
       Though values of 1 or more are recommended due to a quota resolution of
       one second.

       If  the  configured  time  period (e.g. "1w" for babymary) is over, the
       time budget will be restored to the configured value thus allowing  the
       user to access squid with a fresh budget.

       If  the  time  between  the current request and the previous request is
       greater than pauselen (default 5 minutes and  adjustable  with  command
       line  parameter  -p  ), the current request will be considered as a new
       request and the time budget will not be decreased. If the time is  less
       than  pauselen  ,  then both requests will be considered as part of the
       same active time period and the time budget will be  decreased  by  the
       time  difference.  This allows the user to take arbitrary breaks during
       Internet access without losing their time budget.

FURTHER IDEAS
       The following ideas could further improve this  helper.  Maybe  someone
       wants to help? Any support or feedback is welcome!

       There should be a way for a user to see their configured and remaining
              time  budget.  This could be realized by implementing a web page
              accessing the database of the helper showing  the  corresponding
              data. One of the problems to be solved is user authentication.

       We could always return "OK" and use the module simply as an Internet
              usage tracker showing who has stayed how long in the WWW.

AUTHOR
       This  program  and  documentation  was  written  by  Dr. Tilmann Bubeck
       <t.bubeck@reinform.de>

COPYRIGHT
        * Copyright (C) 1996-2023 The Squid Software Foundation and  contribu-
       tors
        *
        * Squid software is distributed under GPLv2+ license and includes
        * contributions from numerous individuals and organizations.
        * Please see the COPYING and CONTRIBUTORS files for details.

       This program and documentation is copyright to the authors named above.

       Distributed under the GNU General Public License (GNU GPL) version 2 or
       later (GPLv2+).

QUESTIONS
       Questions on the usage of this program can be sent to the  Squid  Users
       mailing list <squid-users@lists.squid-cache.org>

REPORTING BUGS
       Bug  reports  need  to  be  made  in  English.   See http://wiki.squid-
       cache.org/SquidFaq/BugReporting for details of what you need to include
       with your bug report.

       Report bugs or bug fixes using http://bugs.squid-cache.org/

       Report  serious  security  bugs  to Squid Bugs <squid-bugs@lists.squid-
       cache.org>

       Report ideas for new improvements to the Squid Developers mailing  list
       <squid-dev@lists.squid-cache.org>

SEE ALSO
       squid(8), GPL(7),
       The Squid FAQ wiki http://wiki.squid-cache.org/SquidFaq
       The Squid Configuration Manual http://www.squid-cache.org/Doc/config/

                                 22 March 2011           ext_time_quota_acl(8)

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