PKGBUILDs/community/apache13-mod_bandwidth/README
2009-10-09 21:15:33 -05:00

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/* ====================================================================
* Copyright (c) 1995 The Apache Group. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* 4. The names "Apache Server" and "Apache Group" must not be used to
* endorse or promote products derived from this software without
* prior written permission.
*
* 5. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE APACHE GROUP OR
* IT'S CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Group and was originally based
* on public domain software written at the National Center for
* Supercomputing Applications, University of Illinois, Urbana-Champaign.
* For more information on the Apache Group and the Apache HTTP server
* project, please see <http://www.apache.org/>.
*
*/
/****************************************************************************
* Title : Bandwidth management
* File : mod_bandwidth.c
* Author : Yann Stettler (stettler@cohprog.com)
* Date : 12 January 2003
* Version : 2.0.6 for Apache 1.3+
*
* Description :
* Provide bandwidth usage limitation either on the whole server or
* one a per connection basis based on the size of files, directory
* location or remote domain/IP.
*
* Revision : 08/04/97 - "-1" value for LargeFileLimit to disable any
* limits for that kind of files.
* 01/26/98 - Include in_domain() and in_ip() in this file and
* make them static so it will work with Apache 1.3x
* 03/29/98 - Change to set bandwidth in VirtualHost directive
* 07/17/99 - Minor changes to remove warnings at compil time
*
* Allow the use of the network/mask format when
* setting a bandwidth for a remote host/network.
* (Thanks to Sami Kuhmonen for the patch)
*
* New directive BandWidthPulse
*
* 10/14/00 - Minor bug fixed
* 12/15/00 - Bug fix when using mmap
* 08/29/01 - Add a directive to change the data directory
* (Thanks to Awesome Walrus <walrus@amur.ru> )
* 01/12/03 - Add MaxConnection directive to limit the number
* of simultaneous connections.
*
***************************************************************************
* Copyright (c)1997 Yann Stettler and CohProg SaRL. All rights reserved.
* Written for the Apache Group by :
*
* Yann Stettler
* stettler@cohprog.com
* http://www.cohprog.com/
* http://www.animanga.com/
*
* Based on the original default_handler module and on bw_module 0.2 from
* Etienne BERNARD (eb@via.ecp.fr) at VIA Centrale Reseaux, ECP, France
*
* Many thanks to Colba Net Inc (Montreal) for their sponsoring of
* improvements to this module.
*
***************************************************************************/
/*
* Instruction :
* -------------
*
* Note : this module was writen for Apache 1.3.x and tested on it
*
* Installation :
*
* 1) Insert the following line at the end of the "Configuration" file :
* Module bandwidth_module mod_bandwidth.o
*
* WARNING : This behaviour is not the same between the various main versions
* of Apache. Please, read the instruction on our website for the
* instructions concerning the latest release :
* http://www.cohprog.com/v3/bandwidth/doc-en.html
*
* 2) Run the "Configure" program and re-compile the server with "make".
*
* 3) Create the following directories with "rwx" permission to everybody :
* (or rwx for the user under which Apache run : Usualy "nobody")
* /tmp/apachebw
* /tmp/apachebw/link
* /tmp/apachebw/master
*
* /==== by Awesome Walrus <walrus@amur.ru> =====================\
* Or you may change this name by using BandWidthDataDir global
* configuration directive. See below for details.
* \==== by Awesome Walrus <walrus@amur.ru> =====================/
*
* Note that if any of those directories doesn't exist, or if they can't
* be accessed by the server, the module is totaly disabled except for
* logging an error message in the logfile.
*
* Be careful that on some systems the content of the /tmp directory
* is deleted at boot time or every so often by a cronjob. If that the
* case, either disable this feature or change the location of the
* directories used by the module in the sources bellow.
*
* Server configuration directive :
* --------------------------------
*
* /==== by Awesome Walrus <walrus@amur.ru> =====================\
* - BandWidthDataDir
* Syntax : BandWidthDataDir <directory>
* Default : "/tmp/apachebw"
* Context : server config
*
* Sets the name of the directory used by mod_bandwidth to store
* its internal temporary information.
* \==== by Awesome Walrus <walrus@amur.ru> =====================/
*
* - BandWidthModule
* Syntax : BandWidthModule <On|Off>
* Default : Off
* Context : per server config
*
* Enable or disable totaly the whole module. By default, the module is
* disable so it is safe to compile it in the server anyway.
*
* PLEASE, NOTE THAT IF YOU SET A BANDWIDTH LIMIT INSIDE A VIRTUALHOST
* BLOCK, YOU ALSO __NEED__ TO PUT THE "BandWidthModule On" DIRECTIVE
* INSIDE THAT VIRTUALHOST BLOCK !
*
* IF YOU SET BANDWIDTH LIMITS INSIDE DIRECTORY BLOCKS (OUTSIDE OF
* ANY VIRTUALHOST BLOCK), YOU ONLY NEED TO PUT THE "BandWidthModule On"
* DIRECTIVE ONCE, OUTSIDE OF ANY VIRTUALHOST OR DIRECTORY BLOCK.
*
* - BandWidthPulse
* Syntax : BandWidthPulse <microseconds>
* Default :
* Context : per server config
*
* Change the algorithm used to calculate bandwidth and transmit data.
* In normal mode (old mode), the module try to transmit data in packets
* of 1KB. That mean that if the bandwidth available is of 512B, the
* module will transmit 1KB, wait 2 seconds, transmit another 1KB and
* so one.
*
* Seting a value with "BandWidthPulse", will change the algorithm so
* that the server will always wait the same amount of time between
* sending packets but the size of the packets will change.
* The value is in microseconds.
* For example, if you set "BandWidthPulse 1000000" (1 sec) and the
* bandwidth available is of 512B, the sever will transmit 512B,
* wait 1 second, transmit 512B and so on.
*
* The advantage is a smother flow of data. The disadvantage is
* a bigger overhead of data transmited for packet header.
* Setting too small a value (bellow 1/5 of a sec) is not realy
* useful and will put more load on the system and generate more
* traffic for packet header.
*
* Note also that the operating system may do some buffering on
* it's own and so defeat the purpose of setting small values.
*
* This may be very useful on especialy crowded network connection :
* In normal mode, several seconds may happen between the sending of
* a full packet. This may lead to timeout or people may believe that
* the connection is hanging. Seting a value of 1000000 (1 sec) would
* guarantee that some data are sent every seconds...
*
* Directory / Server / Virtual Server configuration directive :
* -------------------------------------------------------------
*
* - BandWidth
* Syntax : BandWidth <domain|ip|all> <rate>
* Default : none
* Context : per directory, .htaccess
*
* Limit the bandwidth for files in this directory and
* sub-directories based on the remote host <domain> or
* <ip> address or for <all> remote hosts.
*
* Ip addresses may now be specified in the network/mask format.
* (Ie: 192.168.0.0/21 )
*
* The <rate> is in Bytes/second.
* A <rate> of "0" means no bandwidth limit.
*
* Several BandWidth limits can be set for the same
* directory to set different limits for different
* hosts. In this case, the order of the "BandWidth"
* keywords is important as the module will take the
* first entry which matches the client address.
*
* Example :
* <Directory /home/www>
* BandWidth ecp.fr 0
* BandWidth 138.195 0
* BandWidth all 1024
* </Directory>
*
* This will limit the bandwith for directory /home/www and
* all it's subdirectories to 1024Bytes/sec, except for
* *.ecp.fr or 138.195.*.* where no limit is set.
*
* - LargeFileLimit
* Syntax : LargeFileLimit <filesize> <rate>
* Default : none
* Context : per directory, .htaccess
*
* Set a maximal <rate> (in bytes/sec) to use when transfering
* a file of <filesize> KBytes or more.
*
* Several "LargeFileLimit" can be set for various files sizes
* to create range. The rate used for a given file size will be
* the one of the matching range.
*
* A <rate> of "0" mean that there isn't any limit based on
* the size.
*
* A <rate> of "-1" mean that there isn't any limit for that type
* of file. It's override even a BandWidth limit. I found this usefull
* to give priority to very small files (html pages, very small pictures)
* while seting limits for larger files... (users with their video files
* can go to hell ! :)
*
* Example :
* If the following limits are set :
* LargeFileLimit 200 3072
* LargeFileLimit 1024 2048
*
* That's mean that a file of less than 200KBytes won't be
* limited based on his size. A file with a size between
* 200KBytes (included) and 1023Kbytes (included) will be
* limited to 3072Bytes/sec and a file of 1024Kbytes or more
* will be limited to 2048Bytes/sec.
*
* - MinBandWidth
* Syntax : MinBandWidth <domain|ip|all> <rate>
* Default : all 256
* Context : per directory, .htaccess
*
* Set a minimal bandwidth to use for transfering data. This
* over-ride both BandWidth and LargeFileLimit rules as well
* as the calculated rate based on the number of connections.
*
* The first argument is used in the same way as the first
* argument of BandWidth.
*
* <rate> is in bytes per second.
*
* A rate of "0" explicitly means to use the default minimal
* value (256 Bytes/sec).
*
* A rate of "-1" means that the minimal rate is equal to the
* actual rate defined by BandWidth and LargeFileLimit.
* In fact, that means that the final rate won't depend
* of the number of connections but only on what was defined.
*
* Example :
* If BandWidth is set to "3072" (3KBytes/sec) and MinBandWidth
* is set to "1024" (1KBytes/sec) that means :
* - if there is one connection, the file will be transfered
* at 3072 Bytes/sec.
* - if there is two connections, each files will be transfered
* at 1536 Bytes/sec.
* - if there is three or more connections, each files will be
* transfered at 1024 Bytes/sec. (Minimal of 1024 Bytes/sec).
*
* If MinBandWidth is set to "-1" that means :
* - if there is one connection, the file will be transfered
* at 3072 Bytes/sec.
* - if there is two or more connections, each files will be
* transfered at 3072 Bytes/sec. In effect, the rate doesn't
* depend anymore on the number of connections but only on
* the configuration values.
*
* Note that the total transfer rate will never exceed your physical
* bandwidth limitation.
*
* Note : If both a "BandWidth" and a "LargeFileLimit" limit apply,
* the lowest one will be used. (But never lower than the
* "MinBandWidth" rate)
*
* If both a virtual server limit is defined and another
* apply for a directory under this virtual server, the
* directory limit will over-ride it.
*
* If a limit is defined outside a Directory or VirtualHost
* directive, it will act as default on a per virtual server
* basis. (Ie: each virtual server will have that limit,
* _independantly_ of the other servers)
*
* - MaxConnection
* Syntax : MaxConnection <connections>
* Default : 0 (illimited)
* Context : per directory, .htaccess
*
* Restrict the number of maximum simultanous connections. If the
* limit is reached, new connections will be rejected.
"
* A value of 0 mean that there isn't any limits.
*
* Implementation notes :
* ----------------------
*
* 1) This module isn't called when serving a cgi-script. In this
* case, it's the functions in mod_cgi.c that handle the connection.
*
* That's not a bug : I didn't want to change the cgi_module and
* I was too lazy to do it anyway.
*
* 2) The rate of data transmission is only calculated. It isn't
* measured. Which mean that this module calculates the final
* rate that should apply for a file and simply divides this
* number by the number of actual connections subject to the
* same "per directory" directives.
*
* 3) On the "+" side, the module regulate the speed taking
* into account the actual time that was needed to send the
* data. Which also mean that if data are read by the client
* at a slowest rate than the limit, no time will be lost and
* data will be sent as fast as the client can read them (but
* no faster than the limited rate :) ...
*
* 4) Some kind of buffering is done as side effect. Data are
* sent in packet of 1024 Bytes which seems a good value
* for TCP/IP.
* If another packet size is wanted, change the value of
* "#define PACKET" in the codes bellow.
*
* 5) The default value for MinBandWidth is defined by :
* "#define MIN_BW_DEFAULT" (in Bytes/sec)
*
* 6) Don't define "BWDEBUG" for a production server :
* this would log a _lot_ of useless informations for
* debuging purpose.
*
*/