Index: binaries/data/mods/public/gui/session/session.js =================================================================== --- binaries/data/mods/public/gui/session/session.js +++ binaries/data/mods/public/gui/session/session.js @@ -1567,6 +1567,7 @@ /** * Send a report on the gamestatus to the lobby. + * Keep in sync with source/tools/XpartaMuPP/LobbyRanking.py */ function reportGame() { Index: source/tools/LICENSE.txt =================================================================== --- source/tools/LICENSE.txt +++ source/tools/LICENSE.txt @@ -69,4 +69,4 @@ MIT XpartaMuPP - GPL version 2 (or later) + GPL version 2 (or later) - see license_gpl-2.0.txt Index: source/tools/XpartaMuPP/EcheLOn.py =================================================================== --- source/tools/XpartaMuPP/EcheLOn.py +++ source/tools/XpartaMuPP/EcheLOn.py @@ -771,6 +771,8 @@ optp.add_option('-s', '--server', help='address of the ejabberd server', action='store', dest='xserver', default="localhost") + optp.add_option('-t', '--disable-tls', help='Pass this argument to disable TLS encryption', + action='store_true', dest='xdisabletls', default=False) opts, args = optp.parse_args() @@ -786,7 +788,7 @@ xmpp.register_plugin('xep_0060') # PubSub xmpp.register_plugin('xep_0199') # XMPP Ping - if xmpp.connect((opts.xserver, 5222)): + if xmpp.connect((opts.xserver, 5222), True, not opts.xdisabletls): xmpp.process(threaded=False) else: logging.error("Unable to connect") Index: source/tools/XpartaMuPP/README.md =================================================================== --- source/tools/XpartaMuPP/README.md +++ source/tools/XpartaMuPP/README.md @@ -1,34 +1,100 @@ -# 0 A.D. Multiplayer Lobby Setup +# 0 A.D. / Pyrogenesis Multiplayer Lobby Setup -## Introduction +This README explains how to setup a custom Pyrogenesis Multiplayer Lobby server that can be used with the Pyrogenesis game. -Some commands assume some apt-get based distribution. `lobby.wildfiregames.com` should be replaced -by your own domain name (or `localhost`) in all commands below. +## Service description +The Pyrogenesis Multiplayer Lobby consists of three components: -## ejabberd +* **XMPP server: ejabberd**: + The XMPP server provides the platform where users can register accounts, chat in a public room and can interact with lobby bots. + Currently, ejabberd is the only XMPP server software supported (by the ipstamp module for XpartaMuPP). -These instructions for ejabberd assume you're running a Debian version where at least ejabberd -17.03 is available (currently Debian Stretch with enabled backports), as that's the minimum -ejabberd version which is required for the custom ejabberd module to work. +* **Gamelist bot: XpartaMuPP**: + This bot allows players to host and join online multiplayer matches. + It utilizes the ejabberd ipstamp module to inform players of IP addresses of hosting players. -### Install ejabberd +* **Rating bot: EcheLOn*: + This bot allows players to gain a rating that reflects their skill based on online multiplayer matches. + It is by no means necessary for the operation of a lobby in terms of match-making and chatting. -* Install `ejabberd`: +## Service choices +Before installing the service, you have to make some decisions: + +#### Choice: Domain Name +Decide on a domain name where the service will be provided. +This document will use `lobby.wildfiregames.com` as an example. +If you intend to use the server only for local testing, you may choose `localhost`. + +#### Choice: Rating service +Decide whether or not you want to employ the rating service. +If you decide to not provide the rating service, you may skip the instructions for the rating bot in this document. + +#### Choice: Pyrogenesis version compatibility +Decide whether you want to support serving multiple Pyrogenesis versions. + +Serving multiple versions of Pyrogenesis allows for seamless version upgrading on the backend and +allows players that don't have the most recent version of Pyrogenesis yet to continue to play until +the new release is available for their platform (applies mostly to linux distributions). + +If you decide to do so, you should use a naming pattern that includes the targetted Pyrogenesis version. +For example to provide a Multiplayer Lobby for Pyrogenesis Alpha 23 "Ken Wood", +name the lobby room `arena23` instead of `arena` and use `xpartamupp23` and `echelon23` as lobby bot names. +Then when a version 24 of Pyrogenesis is employed, you can easily add `arena24`, `xpartamupp24` and `echelon24`. +If you only want to use the service for local testing, you can stick to a single room and a single gamelist and rating bot. + +## 1. Install dependencies + +This section explains how to install the required software on a Debian-based linux distribution. +For other operating systems, use the according package manager or consult the official documentation of the software. + +### 1.1 Install ejabberd + +The version requirement for ejabberd is 17.03 or later (due to the ipstamp module format). + +* Install `ejabberd` using the following command. Alternatively see . ``` $ apt-get install ejabberd ``` -* Configure it, by setting the domain name (e.g. `localhost` if you installed it on your - development computer) and add an admin user.: +* Confirm that the ejabberd version you installed is the one mentioned above or later: + + ``` + $ ejabberdctl status + ``` + +* Configure ejabberd by setting the domain name of your choice and add an `admin` user.: ``` $ dpkg-reconfigure ejabberd ```` -You should now be able to connect to this XMPP server using a normal XMPP client. +You should now be able to connect to this XMPP server using any XMPP client. -### Installation of the custom ejabberd module +### 1.2 Install python3 and SleekXmpp + +* The lobby bots are programmed in python3 and use SleekXMPP to connect to the lobby. Install these dependencies using: + + ``` + $ apt-get install python3 python3-sleekxmpp + ``` + +* Confirm that the SleekXmpp version is 1.3.1 or later: + + ``` + pip3 show sleekxmpp + ``` + +* If you would like to run the rating bot, you will need to install SQLAlchemy for python3: + + ``` + $ apt-get install python3-sqlalchemy + ``` + +### 1.3 Install ejabberd ipstamp module + +The ejabberd ipstamp module has the purpose of inserting the IP address of the hosting players into the gamelist packet. +That enables players to connect to each others games. * Adjust `/etc/ejabberd/ejabberdctl.cfg` and set `CONTRIB_MODULES_PATH` to the directory where you want to store `mod_ipstamp`: @@ -52,28 +118,154 @@ $ ejabberdctl module_install mod_ipstamp ``` -* Add `mod_ipstamp` to the modules ejabberd should load in`/etc/ejabberd/ejabberd.yml`: +## 2. Configure ejabberd mod_ipstamp + +The ejabberd configuration in the remainder of this document is performed by editing `/etc/ejabberd/ejabberd.yml`. +For a full documentation of the ejabberd configuration, see . +If something goes wrong with ejabberd, check `/var/log/ejabberd/ejabberd.log` + +* Add `mod_ipstamp` to the modules ejabberd should load: ``` modules: mod_ipstamp: {} ``` -* Reload ejabberd's configuration: +* Reload the ejabberd config. + This should be done every few steps, so that configuration errors can be identified as soon as possible. ``` $ ejabberdctl reload_config ``` -If something goes wrong, check `/var/log/ejabberd/ejabberd.log` +## 3. Configure ejabberd connectivity + +The settings in this section ensure that connections can be built where intended, and only where intended. + +### 3.1 Disable IPv6 +Since the enet library which Pyrogenesis uses for multiplayer mode does not support IPv6, ejabberd must be configured to not use IPv6: + + ``` + listen: + ip: "0.0.0.0" + ``` + +### 3.2 Enable STUN +ejabberd and Pyrogenesis support the STUN protocol, which allows players to connect to each others games, even if the host did not configure +the router and forward the UDP port. Enabling STUN is optional but recommended. + + ``` + listen: + - + port: 3478 + transport: udp + module: ejabberd_stun + ``` + +### 3.3 Enable keep-alive + +* This helps with users becoming disconnected + + ``` + modules: + mod_ping: + send_pings: true + ``` + +### 3.3 Disable unused services + +* Disable the currently unused server-to-server communication: + + ``` + listen: + ## - + ## port: 5269 + ## ip: "::" + ## module: ejabberd_s2s_in + ``` + +* Protect the administrative webinterface at from external access by disabling or restriction to `localhost`: + + ``` + listen: + - + port: 5280 + ip: "127.0.0.1" + ``` + +* Disable some unused modules: + + ``` + modules: + ## mod_echo: {} + ## mod_irc: {} + ## mod_shared_roster: {} + ## mod_vcard: {} + ## mod_vcard_xupdate: {} + ``` + +### 3.4 Enable TLS encryption + +Depending on whether you use the server for a player audience or only for local testing, +you may have to either obtain and install a certificate with ejabberd or disable TLS encryption. + +#### Choice A: No encryption +If you intend to use the server solely for local testing, you may disable TLS encryption in the ejabberd config: + + ``` + listen: + starttls_required: false + ``` + +#### Choice B: Self-signed certificate + +If you want to use the server for local testing only, you may use a self-signed certificate to test encryption. + +* Create the key file for certificate: + + ``` + openssl genrsa -out key.pem 2048 + ``` +* Create the certificate file. “common name” should match the domainname. + + ``` + openssl req -new -key key.pem -out request.pem + ``` + +* Sign the certificate: + + ``` + openssl x509 -req -days 900 -in request.pem -signkey key.pem -out certificate.pem + ``` + +* Store it as the ejabberd certificate: + + ``` + $ cat key.pem request.pem > /etc/ejabberd/ejabberd.pem + ``` + +Notice the lobby bots currently reject self-signed certificates. + +#### Choice C: Let's Encrypt certificate +To secure user authentication and communication with modern encryption and to comply with privacy laws, +ejabberd should be configured to use TLS with a proper, trusted certificate. +A free, valid and trusted TLS certificate may be obtained from some certificate authorites, such as Let's Encrypt: + + + +## 3. Configure ejabberd use policy -### Ejabberd configuration +The settings in this section grant or restrict user access rights. -A web administration interface is available at http://localhost:5280/admin. Use the admin user -credentials (full JID (user@domain)) to log in. Changing settings there is also possible, but some -of those might not persist on restart. +* Prevent the rooms from being destroyed if the last client leaves it: -The rest of this section should be done by editing `/etc/ejabberd/ejabberd.yml`. + ``` + modules: + mod_muc: + access_persistent: muc_admin + default_room_options: + persistent: true + ``` * Allow users to create accounts using the game via in-band registration: @@ -83,111 +275,278 @@ all: allow ``` -* Check list of registered users: +### Optional use policies + +* (Optional) Prevent users from creating new rooms: ``` - $ ejabberdctl registered_users lobby.wildfiregames.com + access_rules: + muc_admin: + - allow: admin + + modules: + mod_muc: + access_create: muc_admin + ``` + +* (Optional) Increase the maximum number of users from the default 200: + + ``` + mod_muc: + max_users: 5000 + default_room_options: + max_users: 1000 ``` -* `XpartaMuPP` and `EcheLOn` need a user accountsto function, so create them using: +* (Optional) Prevent users from changing the room topic: ``` - $ ejabberdctl register echelon lobby.wildfiregames.com secure_password - $ ejabberdctl register xpartamupp lobby.wildfiregames.com secure_password + mod_muc: + default_room_options: + allow_change_subj: false ``` -* The bots also need to be able to get the IPs of users hosting a match, which is what - `mod_ipstamp` does. +* (Optional) Prevent malicious users from registering new accounts quickly if they were banned. + Notice this also prevents players using the same internet router from registering for that time if they want to play together. + + ``` + registration_timeout: 3600 + ``` - * Create an ACL for the bot (or bots): +* (Optional) Enable room chatlogging. + Make sure to mention this collection and the purposes in the Terms and Conditions to comply with personal data laws. + + ``` + modules: + mod_muc_log: + outdir: "/lobby/logs" + dirtype: plain + file_format: plaintext + timezone: universal + mod_muc: + default_room_options: + logging: true + ``` + +* (Optional) Grant specific moderators to get the IP address of a user: + See also `https://xmpp.org/extensions/xep-0133.html#get-user-stats`. ``` acl: - bots: + admin: user: - - "echelon@lobby.wildfiregames.com" - - "xpartamupp@lobby.wildfiregames.com" + - "username@lobby.wildfiregames.com" ``` -* Add an access rule (name it `ipbots` since that is what the module expects): +* (Optional) Ban specific IP addresses or subnet masks for persons that create new accounts after having been banned from the room: ``` - access: + acl: + blocked: + ip: + - "12.34.56.78" + - "12.34.56.0/8" + - "12.34.0.0/16" + ... + access_rules: + c2s: + - deny: blocked + - allow + register: + - deny: blocked + - allow + ``` + +## 4. Setup lobby bots + +### 4.1 Register lobby bot accounts + +* Check list of registered users: + + ``` + $ ejabberdctl registered_users lobby.wildfiregames.com + ``` + +* Register the accounts of the lobby bots. + The rating account is only needed if you decided to enable the rating service. + + ``` + $ ejabberdctl register echelon23 lobby.wildfiregames.com secure_password + $ ejabberdctl register xpartamupp23 lobby.wildfiregames.com secure_password + ``` + +### 4.2 Authorize lobby bots with ejabberd + +* The bots and the Pyrogenesis STUN client need to be able to see real JIDs of users. + Instead of granting them administrator rights to the bots, real JIDs of all users can become public: + + ``` + modules: + mod_muc: + default_room_options: + anonymous: false + ``` + +* The bots need an ACL to be able to get the IPs of users hosting a match (which is what `mod_ipstamp` does). + + ``` + acl: + bots: + ## Don't use a regex, to prevent others from obtaining permissions after registering such an account. + - user: "xpartamupp23@lobby.wildfiregames.com" + - user: "echelon23@lobby.wildfiregames.com" + ``` + +* Add an access rule for `ipbots` (as expected by `mod_ipstamp`). + Also add a rule allowing bots to create PubSub nodes: + + ``` + access_rules: ipbots: - bots: allow + - allow: bots + + pubsub_createnode: + - allow: bots ``` * Due to the amount of traffic the bot may process, give the group containing bots either unlimited or a very high traffic shaper: ``` - c2s_shaper: - admin: none - bots: none - all: normal + shaper_rules: + c2s_shaper: + - none: admin, bots + - normal ``` -* The bots need the real JIDs of the MUC users, which are only available for admin users, - therefore the following setting is necessary: +* Finally reload ejabberd's configuration: ``` - access: - muc_admin: - admin: allow - bots: allow + $ ejabberdctl reload_config ``` -### MUC room setup +### 4.3 Running XpartaMuPP - XMPP Multiplayer Game Manager -To enable the bot to send the game list to players it needs the JIDs of the players, so the MUC -room has to be configured as non-anonymous room. In case that you want to host multiple lobby -rooms adding an ACL for MUC admins to which the bots are added, which is used for `access_admin` -in the `mod_muc` configuration would be advisable. +* Execute the following command to run the gamelist bot: -## Running XpartaMuPP - XMPP Multiplayer Game Manager + ``` + $ python3 XpartaMuPP.py --domain lobby.wildfiregames.com --login xpartamupp23 --password XXXXXX --nickname GamelistBot --room arena --elo echelon23 + ``` + +If you want to run XpartaMuPP without a rating bot, the `--elo` argument should be omitted. +Pass `--disable-tls` if you did not enable proper TLS encryption on the server. +Run `python3 XpartaMuPP.py --help` for the full list of options -You need to have Python 3 and SleekXmpp 1.3.1+ installed +If the connection and authentication succeeded, you should see the following messages in the console: - # apt-get install python3 python3-sleekxmpp + ``` + INFO JID set to: xpartamupp23@lobby.wildfiregames.com/CC + INFO XpartaMuPP started + ``` -If you would like to run the leaderboard database, you will need to install SQLAlchemy for Python 3. +### 4.4 Running EcheLOn - XMPP Multiplayer Rating Manager - # apt-get install python3-sqlalchemy +This bot can be thought of as a module of XpartaMuPP in that IQs stanzas sent to XpartaMuPP are +forwarded onto EcheLOn if its corresponding EcheLOn is online and ignored otherwise. +EcheLOn handles all aspects of operation related to ELO, the chess rating system invented by Arpad Elo. +Players gain a rating after a rated 1v1 match. +The score difference after a completed match is relative to the rating difference of the players. + +* (Optional) Some constants of the algorithm may be edited by experienced administrators at the head of `ELO.py`: + + ``` + # Difference between two ratings such that it is + # regarded as a "sure win" for the higher player. + # No points are gained or lost for such a game. + elo_sure_win_difference = 600.0 + + # Lower ratings "move faster" and change more + # dramatically than higher ones. Anything rating above + # this value moves at the same rate as this value. + elo_k_factor_constant_rating = 2200.0 + ``` -Then execute the following command to setup the database. +* To initialize the `lobby_rankings.sqlite3` database, execute the following command: + ``` $ python3 LobbyRanking.py + ``` + +* Execute the following command to run the rating bot: -Execute the following command to run the bot with default options: + ``` + $ python3 EcheLOn.py --domain lobby.wildfiregames.com --login echelon23 --password XXXXXX --nickname RatingBot --room arena23 + ``` - $ python3 XpartaMuPP.py +Run `python3 EcheLOn.py --help` for the full list of options -or rather a similar command to run a properly configured program: +## 5. Configure Pyrogenesis for the new Multiplayer Lobby - $ python3 XpartaMuPP.py --domain lobby.wildfiregames.com --login wfgbot --password XXXXXX --nickname WFGbot --room arena +The Pyrogenesis client is now going to be configured to become able to connect to the new Multiplayer Lobby. -or if you want to run XpartaMuPP with the corresponding rating bot detailed in the next section: +The Pyrogenesis documentation of configuration files can be found at . +Available Pyrogenesis configuration settings are specified in `default.cfg`, see . - $ python3 XpartaMuPP.py --domain lobby.wildfiregames.com --login wfgbot --password XXXXXX --nickname WFGbot --room arena --elo echelon +### 5.1 Local Configuration -Run `python3 XpartaMuPP.py --help` for the full list of options + * Visit to identify the local user's Pyrogenesis configuration path depending on the operating system. -If everything is fine you should see something along these lines in your console + * Create or open `local.cfg` in the configuration path. - INFO Negotiating TLS - INFO Using SSL version: 3 - INFO Node set to: wfgbot@lobby.wildfiregames.com/CC - INFO XpartaMuPP started + * Add the following settings that determine the lobby server connection: -Congratulations, you are now running XpartaMuPP - the 0 A.D. Multiplayer Game Manager. + ``` + lobby.room = "arena23" ; Default MUC room to join + lobby.server = "lobby.wildfiregames.com" ; Address of lobby server + lobby.stun.server = "lobby.wildfiregames.com" ; Address of the STUN server. + lobby.require_tls = true ; Whether to reject connecting to the lobby if TLS encryption is unavailable. + lobby.verify_certificate = true ; Whether to reject connecting to the lobby if the TLS certificate is invalid. + lobby.xpartamupp = "xpartamupp23" ; Name of the server-side XMPP-account that manage games + lobby.echelon = "echelon23" ; Name of the server-side XMPP-account that manages ratings + ``` -## Run EcheLOn - XMPP Rating Bot + If you disabled TLS encryption, set `require_tls` to `false`. + If you employed a self-signed certificate, set `verify_certificate` to `false`. -This bot can be thought of as a module of XpartaMuPP in that IQs stanzas sent to XpartaMuPP are -forwarded onto EcheLOn if its corresponding EcheLOn is online and ignored otherwise. This is by no -means necessary for the operation of a lobby in terms of creating/joining/listing games. -EcheLOn handles all aspects of operation related to ELO. +### 5.2 Test the Multiplayer Lobby + +You should now be able to join the new multiplayer lobby with the Pyrogenesis client and play multiplayer matches. + +* To confirm that the match hosting works as intended, create two user accounts, host a game with one, join the game with the other account. + +* To confirm that the rating service works as intended, resign a rated 1v1 match with two accounts. + +### 5.3 Terms and Conditions + +Players joining public servers are subject to Terms and Conditions of the service provider and subject to privacy laws such as GDPR. +If you intend to use the server only for local testing, you may skip this step. + +`Terms_of_Service.txt` explain the contract. +`Terms_of_Use.txt` explain what the user should and should not do. +`Privacy_Policy.txt` explain how personal data is handled. + +* To use Wildfire Games Terms as a template, obtain our Terms from a copy of the game or from or from + + +* Replace all occurrences of `Wildfire Games` in the files with the one providing the new server. + +* Update the `Terms_of_Use.txt` depending on which behavior you would like to (not) see on your service. + +* Update the `Privacy_Policy.txt` depending on the user data processing in relation to the usage policies. + Make sure to not violate privacy laws such as GDPR or COPPA while doing so. + +* The terms should be published online, so users can save and print them. + Add to your `local.cfg`: + + ``` + lobby.terms_url = "https://lobby.wildfiregames.com/terms/"; Allows the user to save the text and print the terms + ``` + +### 5.4 Distribute the configuration + +To make this a public server, distribute your `local.cfg`, `Terms_of_Service.txt`, `Terms_of_Use.txt`, `Privacy_Policy.txt`. -To run EcheLOn: +It may be advisable to create a mod with a modified `default.cfg` and the new terms documents, +see . - $ python3 EcheLOn.py --domain lobby.wildfiregames.com --login echelon --password XXXXXX --nickname Ratings --room arena +Congratulations, you are now running a custom Pyrogenesis Multiplayer Lobby! Index: source/tools/XpartaMuPP/XpartaMuPP.py =================================================================== --- source/tools/XpartaMuPP/XpartaMuPP.py +++ source/tools/XpartaMuPP/XpartaMuPP.py @@ -639,6 +639,8 @@ optp.add_option('-s', '--server', help='address of the ejabberd server', action='store', dest='xserver', default="localhost") + optp.add_option('-t', '--disable-tls', help='Pass this argument to disable TLS encryption', + action='store_true', dest='xdisabletls', default=False) opts, args = optp.parse_args() @@ -654,7 +656,7 @@ xmpp.register_plugin('xep_0060') # PubSub xmpp.register_plugin('xep_0199') # XMPP Ping - if xmpp.connect((opts.xserver, 5222)): - xmpp.process(threaded=False) + if xmpp.connect((opts.xserver, 5222), True, not opts.xdisabletls): + xmpp.process(threaded=False) else: logging.error("Unable to connect") Index: source/tools/XpartaMuPP/mod_ipstamp/COPYING =================================================================== --- source/tools/XpartaMuPP/mod_ipstamp/COPYING +++ /dev/null @@ -1,339 +0,0 @@ - GNU GENERAL PUBLIC LICENSE - Version 2, June 1991 - - Copyright (C) 1989, 1991 Free Software Foundation, Inc., - 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - Everyone is permitted to copy and distribute verbatim copies - of this license document, but changing it is not allowed. - - Preamble - - The licenses for most software are designed to take away your -freedom to share and change it. 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You may copy and distribute the Program (or a work based on it, -under Section 2) in object code or executable form under the terms of -Sections 1 and 2 above provided that you also do one of the following: - - a) Accompany it with the complete corresponding machine-readable - source code, which must be distributed under the terms of Sections - 1 and 2 above on a medium customarily used for software interchange; or, - - b) Accompany it with a written offer, valid for at least three - years, to give any third party, for a charge no more than your - cost of physically performing source distribution, a complete - machine-readable copy of the corresponding source code, to be - distributed under the terms of Sections 1 and 2 above on a medium - customarily used for software interchange; or, - - c) Accompany it with the information you received as to the offer - to distribute corresponding source code. (This alternative is - allowed only for noncommercial distribution and only if you - received the program in object code or executable form with such - an offer, in accord with Subsection b above.) - -The source code for a work means the preferred form of the work for -making modifications to it. For an executable work, complete source -code means all the source code for all modules it contains, plus any -associated interface definition files, plus the scripts used to -control compilation and installation of the executable. However, as a -special exception, the source code distributed need not include -anything that is normally distributed (in either source or binary -form) with the major components (compiler, kernel, and so on) of the -operating system on which the executable runs, unless that component -itself accompanies the executable. - -If distribution of executable or object code is made by offering -access to copy from a designated place, then offering equivalent -access to copy the source code from the same place counts as -distribution of the source code, even though third parties are not -compelled to copy the source along with the object code. - - 4. You may not copy, modify, sublicense, or distribute the Program -except as expressly provided under this License. Any attempt -otherwise to copy, modify, sublicense or distribute the Program is -void, and will automatically terminate your rights under this License. -However, parties who have received copies, or rights, from you under -this License will not have their licenses terminated so long as such -parties remain in full compliance. - - 5. You are not required to accept this License, since you have not -signed it. However, nothing else grants you permission to modify or -distribute the Program or its derivative works. These actions are -prohibited by law if you do not accept this License. Therefore, by -modifying or distributing the Program (or any work based on the -Program), you indicate your acceptance of this License to do so, and -all its terms and conditions for copying, distributing or modifying -the Program or works based on it. - - 6. Each time you redistribute the Program (or any work based on the -Program), the recipient automatically receives a license from the -original licensor to copy, distribute or modify the Program subject to -these terms and conditions. You may not impose any further -restrictions on the recipients' exercise of the rights granted herein. -You are not responsible for enforcing compliance by third parties to -this License. - - 7. If, as a consequence of a court judgment or allegation of patent -infringement or for any other reason (not limited to patent issues), -conditions are imposed on you (whether by court order, agreement or -otherwise) that contradict the conditions of this License, they do not -excuse you from the conditions of this License. If you cannot -distribute so as to satisfy simultaneously your obligations under this -License and any other pertinent obligations, then as a consequence you -may not distribute the Program at all. For example, if a patent -license would not permit royalty-free redistribution of the Program by -all those who receive copies directly or indirectly through you, then -the only way you could satisfy both it and this License would be to -refrain entirely from distribution of the Program. - -If any portion of this section is held invalid or unenforceable under -any particular circumstance, the balance of the section is intended to -apply and the section as a whole is intended to apply in other -circumstances. - -It is not the purpose of this section to induce you to infringe any -patents or other property right claims or to contest validity of any -such claims; this section has the sole purpose of protecting the -integrity of the free software distribution system, which is -implemented by public license practices. Many people have made -generous contributions to the wide range of software distributed -through that system in reliance on consistent application of that -system; it is up to the author/donor to decide if he or she is willing -to distribute software through any other system and a licensee cannot -impose that choice. - -This section is intended to make thoroughly clear what is believed to -be a consequence of the rest of this License. - - 8. If the distribution and/or use of the Program is restricted in -certain countries either by patents or by copyrighted interfaces, the -original copyright holder who places the Program under this License -may add an explicit geographical distribution limitation excluding -those countries, so that distribution is permitted only in or among -countries not thus excluded. In such case, this License incorporates -the limitation as if written in the body of this License. - - 9. The Free Software Foundation may publish revised and/or new versions -of the General Public License from time to time. Such new versions will -be similar in spirit to the present version, but may differ in detail to -address new problems or concerns. - -Each version is given a distinguishing version number. If the Program -specifies a version number of this License which applies to it and "any -later version", you have the option of following the terms and conditions -either of that version or of any later version published by the Free -Software Foundation. If the Program does not specify a version number of -this License, you may choose any version ever published by the Free Software -Foundation. - - 10. If you wish to incorporate parts of the Program into other free -programs whose distribution conditions are different, write to the author -to ask for permission. For software which is copyrighted by the Free -Software Foundation, write to the Free Software Foundation; we sometimes -make exceptions for this. Our decision will be guided by the two goals -of preserving the free status of all derivatives of our free software and -of promoting the sharing and reuse of software generally. - - NO WARRANTY - - 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY -FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN -OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES -PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED -OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF -MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS -TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE -PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, -REPAIR OR CORRECTION. - - 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING -WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR -REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, -INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING -OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED -TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY -YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER -PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE -POSSIBILITY OF SUCH DAMAGES. - - END OF TERMS AND CONDITIONS - - How to Apply These Terms to Your New Programs - - If you develop a new program, and you want it to be of the greatest -possible use to the public, the best way to achieve this is to make it -free software which everyone can redistribute and change under these terms. - - To do so, attach the following notices to the program. It is safest -to attach them to the start of each source file to most effectively -convey the exclusion of warranty; and each file should have at least -the "copyright" line and a pointer to where the full notice is found. - - - Copyright (C) - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License along - with this program; if not, write to the Free Software Foundation, Inc., - 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - -Also add information on how to contact you by electronic and paper mail. - -If the program is interactive, make it output a short notice like this -when it starts in an interactive mode: - - Gnomovision version 69, Copyright (C) year name of author - Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. - This is free software, and you are welcome to redistribute it - under certain conditions; type `show c' for details. - -The hypothetical commands `show w' and `show c' should show the appropriate -parts of the General Public License. Of course, the commands you use may -be called something other than `show w' and `show c'; they could even be -mouse-clicks or menu items--whatever suits your program. - -You should also get your employer (if you work as a programmer) or your -school, if any, to sign a "copyright disclaimer" for the program, if -necessary. Here is a sample; alter the names: - - Yoyodyne, Inc., hereby disclaims all copyright interest in the program - `Gnomovision' (which makes passes at compilers) written by James Hacker. - - , 1 April 1989 - Ty Coon, President of Vice - -This General Public License does not permit incorporating your program into -proprietary programs. If your program is a subroutine library, you may -consider it more useful to permit linking proprietary applications with the -library. If this is what you want to do, use the GNU Lesser General -Public License instead of this License.