Copyright (c) 2007 Dimitri Marinakis.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".
This is a brief how-to and pointers for setting up the “Crypto F200” DSL modem, included in ADSL packs by the specific provider (Forthnet). The modem is used in the PPPoA mode (Point-to-Point Protocol over ATM). This DSL modem is made by Conexant and sold under many commercial names. It is directly supported by Linux kernels 2.6.10 and newer. Patches are available for older kernels.
An example script is provided for manual link activation (usable in firewall/router boxes). SuSE/openSuSE set-up instructions are also provided.
Update (15-Jun-2007) – I was brought to my attention that
PPPoE (Point-to-Point Protocol over Ethernet) is also in use by
Forthnet. In some cases it can be used as a work-around for the
77.49.xx.xx” domain problem
(alternate domain is automagically selected). The 77.49.xx.xx domain
was allocated to Forthnet in August 2006 and it may still be in the
lists of routers/firewalls, preventing access to various sites . See
the companion note http://tlgu.carmen.gr/gnulinuxtips/Sagem
F@st 800 E4 ADSL USB Modem setup - Otenet under GNU-Linux.html
for PPPoE setup (in brief: the
driver module is loaded,
interface is created, nas0 interface is brought up,
is used to control the interface,
is used to call the provider using
ADSL/DSL: Asymmetric / Digital Subscriber Link – (Asymmetric means that the receive/downlink and transmit/uplink speeds are different)
ATM: Asynchronous Transfer Mode – a connection oriented protocol using fixed-size cells, 53 bytes long.
ISDN: Integrated Services Digital Network
PPPoA: Point-to-Point Protocol over ATM
PPPoE: Point-to-Point Protocol over Ethernet
18-Jun-2007 – 77.49.xx.xx mystery solved
15-Jun-2007 – PPPoE pointer
04-Feb-2007 – First release – tlgu.carmen.gr
Werner Almesberger's papers (ATM on Linux and low-end
Information specific to this application
Roman Kagan's cxacru-fw firmware
Firmware instructions for kernels earlier than
man pppd – Point-to-Point Protocol daemon configuration
HOWTO: Εγκατασταση Crypto F200 ADSL Modem (Φάνης
Links in all referenced pages
The usual disclaimer about misconfiguring your system beyond repair or oblueterating your work applies: Don't blame it on me. Do one thing at a time. Read and Learn. Write to tlgu, carmen gr, in case this document contains inaccuracies, errors or if you have some information that others can benefit from.
> lsusb Bus 001 Device 003: ID 0572:cb00 Conexant Systems (Rockwell), Inc. E-Tech ADSL Modem v2
This modem is based on the CONEXANT AccessRunner CX82320-21 ARM processor. The modem's application code (firmware) must be downloaded to the device, at which point it is supported by the cxacru (Conexant Access Runner) driver.
The modem firmware is included in the CD-ROM which accompanies the
modem, in the file driver/Wan/CnxEtU.sys or
driver/Lan/CnxEtU.sys and must be extracted and made available
to the operating system for download to the modem. The two files are
identical, 646784 bytes, Sep 12 2003,
28775c3f6df8c1f364f67d7121191000; similar-named files
available for download may not work with the extractor.
The extractor is called cxacru-fw and is available at http://accessrunner.cvs.sourceforge.net/accessrunner/utils/
Download the file and compile to get the executable:
> gcc cxacru-fw.c -o cxacru-fw
Feed the file containing the driver to the extractor; the output file must be named cxacru-fw.bin and placed in the appropriate directory (/lib/firmware). So, assuming that you have copied the file from the CD-ROM to your working directory:
> ./cxacru-fw CnxEtU.sys cxacru-fw.bin > cp cxacru-fw.bin /lib/firmware
Now as soon as the modem is plugged-in and detected by the operating system, the firmware will be automagically downloaded.
An “ADSL splitter” was included in the package. The telephone line is connected to the port marked “LINE”, the modem is connected to the port marked “MODEM” and the original network termination unit (typically an INTRACOM netmod for ISDN in this part of the world) is connect to the port marked “PHONE”.
A configuration file is needed to match the modem's behavior to what is expected by the provider. PPP over ATM is the selected protocol, while we need to match the Virtual Path Identifier (VPI) and Virtual Circuit Identifier (VCI); these variables identify the next destination of an ATM cell.
# -------------- /etc/cxacru -------------------------------- # # Config file for Conexant AccessRunner # # Driver mode DRIVER_MODE=1 # 1 = normal, 2 = debug, 3 = normal+max speed (without ask adsl status), 4 = debug+max speed (without ask adsl status) # Protocol PROTOCOL_MODE=2 # 1 = RFC1483/2684 routed, 2 = PPP over ATM (pppoa), 3 = RFC1483/2684 bridged, 4 = PPP over Ethernet (pppoe) # Paths BINARY_PATH="/usr/sbin" ATM_PATH="" # ADSL # if OPEN_MODE is blank then cxload uses default mode acoording VID & PID # Values for OPEN_MODE are: # 0 = auto selection, G.Handshake # 1 = auto selection, T1.413 # 2 = G.Handshake # 3 = ANSI T1.413 # 4 = ITU-T G.992.1 (G.DMT) # 5 = ITU-T G.992.2 (G.LITE) OPEN_MODE= # ATM VPI=8 VCI=35 # Specific for RFC1483/2684 routed/bridged # if IP_ADDRESS is blank in bridged mode then it uses DHCP to get IP IP_ADDRESS= NETMASK= GATEWAY= #---------------------------- end of /etc/cxacru ---------------------
Plug in the modem to an available USB port. The modem will be detected and control passed over to the cxacru driver. The modem light will start flashing and then it will light steadily (about 40 seconds).
Following is the relevant output from dmesg (or tail /var/log/messages):
usb 1-2: new full speed USB device using uhci_hcd and address 4 cxacru 1-2:1.0: found firmware cxacru-fw.bin cxacru 1-2:1.0: ADSL line: attemtping to activate [ attemt ping ;-) ] cxacru 1-2:1.0: ADSL line: down cxacru 1-2:1.0: ADSL line: attemtping to activate cxacru 1-2:1.0: ADSL line: training cxacru 1-2:1.0: ADSL line: channel analysis cxacru 1-2:1.0: ADSL line: up (768 kb/s down | 192 kb/s up)
The modem is now ready for operation. You need to activate it by running the Point-to-Point Protocol Daemon (pppd) using a console or through a graphics application (e.g. kinternet).
(skip to next section for SuSE setup using YaST and kinternet)
To establish a connection the point-to-point protocol daemon (pppd) is called, with the appropriate options. The options can be passed directly to pppd or read from a number of places: ~/.ppprc, /etc/ppp/options, /etc/ppp/peers/xxxx. In this example, options are read from a file in /etc/peers, called pppoa-forthnet. It is important to note that pppd will go through all relevant files to complete its options. In order to make sure that the proper options are selected use dump or dryrun (and read the man page).
The command to invoke the daemon is
> pppd call pppoa-forthnet
And the command to properly stop the daemon is
> kill -15 <pppd pid> (SIGTERM – see man 8 pppd)
(or CTRL/C if the daemon is still attached to a terminal – see example below)
When the daemon is invoked it will go through /etc/ppp/peers/pppoa-forthnet and, given the chance, through /etc/ppp/options to look for its options. The pppoa-forthnet script will establish a PPPoA connection for user firstname.lastname@example.org through 8.35 (VPI.VCI). The authentication method used is PAP (Password Authentication Protocol), which means that the password must be entered in the /etc/ppp/pap-secrets file.
For other systems using CHAP (Challenge Handshake Authentication Protocol), the password must be entered in the /etc/ppp/chap-secrets file, in the same manner. Also, compression negotiation may be disabled if it is not supported by the service provider's server (there are several compression options).
The IP address will be determined by the provider's server. The link will not disconnect and, in case of disconnection, will try to reconnect. The Maximum Transfer Unit (MTU) to be negotiated is set at maximum - 16384 bytes (will most probably be negotiated down to 1500 bytes).
The connection, originally ppp0, will be renamed to dsl0 to distinguish it from the analog/ISDN modem connection which can serve as a backup under unusual circumstances (like waiting for the PTT network experts to perform the inevitable reset).
As soon as the connection is initiated, the provider's Domain Name Servers (DNS) will be entered in /etc/ppp/resolv.conf
Following are the necessary /etc/ppp/pap-secrets and /etc/ppp/peers/pppoa-forthnet scripts. Modify as necessary for your application.
#---------------------------- /etc/ppp/pap-secrets --------------------- #hostname * password email@example.com * password #---------------------------- end of /etc/ppp/pap-secrets --------------- #----------------------- /etc/ppp/peers/pppoa-forthnet ------------------ # 070201 dm # Uncomment dump option to see where the options are read from # and how the connection progresses #dump # Use this name to look for a password in the secrets files # User name for peer authentication (if different from name) user firstname.lastname@example.org # (Reference only, do not use) # SuSE uses passwordfd n (password file descriptor) to pass the password #plugin passwordfd.so # Look in /usr/lib/pppd/<pppd version e.g. 2.4.3>/ for pppoatm.so plugin plugin pppoatm.so 8.35 # Add default route to the system routing tables using the peer as gateway defaultroute # Local IP address to be supplied by the peer noipdefault # Disable address/control compression #noaccomp # Disable protocol field compression #nopcomp # Disable CCP (Compression Control Protocol) negotiation #noccp # Disable Van Jacobson style TCP/IP header compression #novj # Do not disconnect if idle idle 0 # Seconds to wait before re-initiating the link holdoff 4 # Try to reopen the connection if it is terminated persist # If it fails many times, however, terminate for good (0 is no limit, default 10) maxfail 20 # Request up to 2 Domain Name Server addresses # These will be passed to /etc/ppp/ip-up script as DNS1 and DNS2 and USEPEERDNS will be set to 1 # An /etc/ppp/resolv.conf file will be created with one or two name server addresses usepeerdns # Attempt to initiate connection, wait for LCP packet if no reply passive # Send LCP echo-request every n seconds to verify connection lcp-echo-interval 5 # If n LCP echo-requests are sent without a valid LCP echo-reply, peer is dead lcp-echo-failure 7 # Do not escape any control characters (for peer) asyncmap 0 # Detach (or not) from the controlling terminal in case of successful connection nodetach #updetach # Don't use IPX protocols noipx # New name for ppp0 ifname dsl0 # Specify maximum sizes for MTU/MRU (despite the fact that it will eventually settle to 1500) mtu 16384 mru 16384 #----------------------- end of /etc/ppp/peers/pppoa-forthnet -----------
Example run with the dump option. Note that /etc/ppp/ip-up and /etc/ppp/ip-down scripts are called on connection establishment and termination:
> pppd call pppoa-forthnet Plugin pppoatm.so loaded. PPPoATM plugin_init PPPoATM setdevname_pppoatm - SUCCESS:8.35 pppd options in effect: nodetach # (from /etc/ppp/peers/pppoa-forthnet) holdoff 4 # (from /etc/ppp/peers/pppoa-forthnet) idle 0 # (from /etc/ppp/peers/pppoa-forthnet) persist # (from /etc/ppp/peers/pppoa-forthnet) maxfail 20 # (from /etc/ppp/peers/pppoa-forthnet) ifname dsl0 # (from /etc/ppp/peers/pppoa-forthnet) dump # (from /etc/ppp/peers/pppoa-forthnet) plugin pppoatm.so # (from /etc/ppp/peers/pppoa-forthnet) active-filter xxx # [don't know how to print value] # (from /etc/ppp/filters) noauth # (from /etc/ppp/options) name email@example.com # (from /etc/ppp/peers/pppoa-forthnet) 8.35 # (from /etc/ppp/peers/pppoa-forthnet) 8.35 # (from /etc/ppp/peers/pppoa-forthnet) asyncmap 0 # (from /etc/ppp/peers/pppoa-forthnet) mru 16384 # (from /etc/ppp/peers/pppoa-forthnet) mtu 16384 # (from /etc/ppp/peers/pppoa-forthnet) passive # (from /etc/ppp/peers/pppoa-forthnet) lcp-echo-failure 7 # (from /etc/ppp/peers/pppoa-forthnet) lcp-echo-interval 5 # (from /etc/ppp/peers/pppoa-forthnet) lcp-restart 2 # (from /etc/ppp/options) lcp-max-configure 60 # (from /etc/ppp/options) noipdefault # (from /etc/ppp/peers/pppoa-forthnet) defaultroute # (from /etc/ppp/peers/pppoa-forthnet) usepeerdns # (from /etc/ppp/peers/pppoa-forthnet) noipx # (from /etc/ppp/peers/pppoa-forthnet) Renamed interface ppp0 to dsl0 Using interface dsl0 Connect: dsl0 <--> 8.35 PAP authentication succeeded local IP address 126.96.36.199 remote IP address 188.8.131.52 primary DNS address 184.108.40.206 secondary DNS address 220.127.116.11 Script /etc/ppp/ip-up finished (pid 23163), status = 0x0
[ifconfig at this point (on another terminal) will provide connection-specific information]
<CTRL/C> entered at the terminal where pppd is attached
Terminating on signal 2 Connect time 0.1 minutes. Sent 0 bytes, received 904 bytes. Connection terminated. Script /etc/ppp/ip-down finished (pid 23314), status = 0x0
The SuSE/openSuSE GNU/Linux distribution's YaST (Yet another Setup Tool) can be used to set up the DSL connection, as follows:
Select Network Devices -> DSL. There are two tabs: DSL Devices and Providers.
Under the DSL Devices tab, click on Add. In the DSL Configuration window select PPP Mode (PPP over ATM) from the drop-down list, enter the VPI/VCI (8.35) – dot notation, don't use a slash...– and select the device activation method (Device Activation: Manually, User Controlled). Click on Next to select the provider.
In the Select Internet Service Provider (ISP) window, click on Custom Providers, New and give the Provider Name (e.g. forthnet_dsl), User Name (e.g. firstname.lastname@example.org) and Password. Click on Next and select Modify DNS When Connected, Automatically Retrieve DNS and External Firewall Interface. Set Idle Time-Out to the desired value (600).
Now you can use kinternet to start and terminate the connection (Right click on the kinternet icon, View Log...). In our example the connection will be terminated automatically after 600 seconds of inactivity have passed.
(on a terminal) will provide an account your connections.
For the curious, SuSE initiates the connection it as follows (use ps aux | grep ppp to get the pppd process id and cat /proc/<pppd pid>/cmdline to verify):
As soon as you click on the kinternet icon the following two commands will be issued:
> /usr/sbin/smpppd-ifcfg --ifcfg=ifcfg-dsl0 --provider=providerx --user=xxxxxxx > /usr/sbin/pppd [options are placed on separate lines for perusal] # Log messages are sent to file descriptor n logfd 9 call pppoatm 8.35 # Maximum Transmit Unit bytes (9178 is the default PPP over ATM default) mtu 1500 # Maximum Receive Unit bytes mru 1500 # Allowed to accept different local and remote addresses ipcp-accept-local ipcp-accept-remote # Disconnect if idle for n seconds idle 600 # Peer is used as the gateway (route removed when PPP connection is broken) defaultroute # Replace existing default route with new default route replacedefaultroute # Don't detach from controlling terminal nodetach # Try to get the name server addresses from the ISP. usepeerdns # Set the interface name (default is ppp0) ifname dsl0 # Provide a parameter (or two?) to the ip-up and ip-down scripts ipparam 'ifcfg-dsl0' 'providerx' # User name for authentication user email@example.com passwordfd 10
Notice that logging is piped to file descriptor 9 and that the password will be read from file descriptor 10 (another way of providing the password to pppd). If you take a look at the log file, however, you will notice the following disconcerting diagnostic:
pppd: Couldn't increase MTU to 9178
Nothing to worry about, really. Apparently, 9178 is the default MTU for PPP over ATM connections. Entering the maximum MTU parameter for negotiation in the relevant SuSE configuration file will rid of this statement (the MTU will still be 1500, though).
#/etc/sysconfig/network/ifcfg-dsl0 BOOTPROTO='none' DEVICE='' MODEM_IP='10.0.0.138' NAME='DSL Connection' PPPD_OPTIONS='' PPPMODE='pppoatm' PROVIDER='provider2' STARTMODE='manual' UNIQUE='' USERCONTROL='yes' VPIVCI='8.35' MTU='16384'
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin St, 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.
The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.
We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.
The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.
A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.
The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.
If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.
You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
C. State on the Title page the name of the publisher of the Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.
You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.
You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.
The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.
In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.
If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.
You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document 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.
10. FUTURE REVISIONS OF THIS LICENSE
The Free Software Foundation may publish new, revised versions of the GNU Free Documentation 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. See http://www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.
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.
<one line to give the program's name and a brief idea of what it does.> Copyright (C) <year> <name of author> 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 St, 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. <signature of Ty Coon>, 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 Library General Public License instead of this License.