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Linux Optimized Link State Routing Protocol (OLSR) IPv6 HOWTO
Lars Strand
<lars (at) unik no>
2004-04-23
Revision History
Revision 1.0 2004-04-23 Revised by: EJH
Final review complete. Document published to the LDP collection.
Revision 0.6 2004-04-19 Revised by: LKS
Thanks to Thomas Zimmerman <thomas (at) zimres net> for a language review!
Updated to latest version number and added a section on plugin-support in
OLSRd. Changed lisence back to [http://www.gnu.org/copyleft/fdl.html] GFDL
Revision 0.5 2004-03-08 Revised by: LKS
An almost complete rewrite. Adding OLSRd (old uOLSR), updated to RFC3626.
Removed NROLSR and CRCOLSR. Converted to XML Docbook. Changed the license
from GFDL to [http://www.opencontent.org/openpub/] OPL due to some GFDL
[http://people.debian.org/~srivasta/Position_Statement.xhtml] problems.
Revision 0.3 2003-08-05 Revised by: LKS
Initial release.
This document describes the software and procedures to set up and use
Optimized Link State Routing Protocol (OLSR) with IPv6 for Linux. OLSR is
used as a routing protocol for Mobile Ad-Hoc Networks ([http://www.ietf.org/
rfc/rfc2501.txt] MANET) (also called "spontaneous network").
-----------------------------------------------------------------------------
Table of Contents
1. Introduction
1.1. Why Ad-Hoc network?
1.2. What is a MANET?
1.3. What is Optimized Link State Routing (OLSR)?
1.4. How does OLSR work?
1.5. What about IBSS (IEEE ad-hoc mode)?
2. IPv6
3. OLSR for Linux
3.1. Installing OLSRd
3.2. Using OLSRd
3.3. What about HNA messages?
3.4. Plugin support
3.5. Optional GUI
3.6. Other OLSR implementations
4. FAQ
5. Useful Resources
6. Copyright, acknowledgments and miscellaneous
6.1. Copyright and License
6.2. How this document was produced
6.3. Feedback
6.4. Acknowledgments
A. GNU Free Documentation License
A.1. PREAMBLE
A.2. APPLICABILITY AND DEFINITIONS
A.3. VERBATIM COPYING
A.4. COPYING IN QUANTITY
A.5. MODIFICATIONS
A.6. COMBINING DOCUMENTS
A.7. COLLECTIONS OF DOCUMENTS
A.8. AGGREGATION WITH INDEPENDENT WORKS
A.9. TRANSLATION
A.10. TERMINATION
A.11. FUTURE REVISIONS OF THIS LICENSE
A.12. ADDENDUM: How to use this License for your documents
1. Introduction
This document describes the software and procedures to set up and use
Optimized Link State Routing Protocol (OLSR) with IPv6 for Linux.
-----------------------------------------------------------------------------
1.1. Why Ad-Hoc network?
An English translation of ad-hoc is "For a particular purpose (improvised,
made up in an instant)" (source: [http://en.wikipedia.org/wiki/
List_of_Latin_phrases#A] Wikipedia). An Ad-hoc network, or "spontaneous
network", is especially useful when dealing with wireless devices in which
some of the devices are part of the network only for the duration of a
communications session and the need for a dynamic network topology is
eminent. A "Mobile Ad hoc Network" is usually called a MANET.
-----------------------------------------------------------------------------
1.2. What is a MANET?
" A MANET consists of mobile platforms (e.g., a router with multiple hosts
and wireless communications devices)--herein simply referred to as 'nodes'
--which are free to move about arbitrarily. The nodes may be located in or on
airplanes, ships, trucks, cars, perhaps even on people or very small devices,
and there may be multiple hosts per router. A MANET is an autonomous system
of mobile nodes. The system may operate in isolation, or may have gateways to
and interface with a fixed network." --- RFC2501: Mobile Ad hoc Networking
(MANET), section 3 (page 3).
-----------------------------------------------------------------------------
1.3. What is Optimized Link State Routing (OLSR)?
"OLSR is a proactive routing protocol for mobile ad hoc networks. The
protocol inherits the stability of a link state algorithm and has the
advantage of having routes immediately available when needed due to its
proactive nature. OLSR is an optimization over the classical link state
protocol, tailored for mobile ad hoc networks."
"OLSR is designed to work in a completely distributed manner and does not
depend on any central entity. The protocol does NOT REQUIRE reliable
transmission of control messages: each node sends control messages
periodically, and can therefore sustain a reasonable loss of some such
messages. Such losses occur frequently in radio networks due to collisions or
other transmission problems." --- RFC3626: OLSR, section 1.3 (page 8)
-----------------------------------------------------------------------------
1.4. How does OLSR work?
"The Optimized Link State Routing Protocol (OLSR) is developed for mobile ad
hoc networks. It operates as a table driven, proactive protocol, i.e.,
exchanges topology information with other nodes of the network regularly.
Each node selects a set of its neighbor nodes as 'multi-point relays' (MPR).
In OLSR, only nodes, selected as such MPRs, are responsible for forwarding
control traffic, intended for diffusion into the entire network. MPRs provide
an efficient mechanism for flooding control traffic by reducing the number of
transmissions required." --- RFC3626: OLSR, section 1 (page 4)
-----------------------------------------------------------------------------
1.5. What about IBSS (IEEE ad-hoc mode)?
The IEEE 802.11 standard defines two modes:
[802-11]
IEEE 802.11 standard
1. Infrastructure mode: The wireless network consist of at least one access
point (AP) connected to the wired network and a set of wireless nodes
(WN). This configuration is called a Basic Service Set (BSS). Extended
Service Set (ESS) is a set of two or more BSSs (multiple cells).
2. Ad hoc mode: Also called "IEEE ad-hoc mode" or "peer-to-peer mode". This
configuration is called Independent Basic Service Set (IBSS) and is
useful for establishing a network where wireless infrastructure does not
exist or where services are not required.
So why use OLSR when we can use "IEEE ad-hoc mode"? IEEE ad-hoc mode does
NOT support multi-hop. See figure below
[multihop]
"IEEE 8102.11 Ad hoc" mode has no support for multihop, something OLSR does
have.
-----------------------------------------------------------------------------
2. IPv6
IP version 6 (IPv6) is a new version of the Internet Protocol, designed as
the successor to IP version 4 (IPv4) [http://www.ietf.org/rfc/rfc791.txt]
[RFC-791]. The changes from IPv4 to IPv6 fall primarily into the following
categories:
<EFBFBD><EFBFBD>*<2A>Expanded addressing capabilities
<EFBFBD><EFBFBD>*<2A>Header format simplification
<EFBFBD><EFBFBD>*<2A>Improved support for extensions and options
<EFBFBD><EFBFBD>*<2A>Flow labeling capability
<EFBFBD><EFBFBD>*<2A>Authentication and privacy capabilities
For more information on IPv6 in general, visit the IETF's IPv6 Working Group.
-----------------------------------------------------------------------------
3. OLSR for Linux
There are several OLSR implementation for Linux, but not all of them
support IPv6. You should know how to enable and use IPv6 on Linux. Peter
Bieringer has written an excellent Linux IPv6 HOWTO.
There is one OLSR implementation that is becoming the "standard" and most
widely used. It goes by the descriptive name "OLSRd" (old Unik-OLSR).
OLSRd is an implementation based on the INRA C code, but has been almost
completely rewritten, so there is not much left of the original INRA code
(that mean it almost GPL). OLSRd also is under very rapid development, and if
you report in a bug, it is usually fixed in a matter of hours.
OLSRd [http://www.olsr.org/index.cgi?action=comp] fully comply to the OLSR
RFC, support for plugins, and it has an optional GUI interface (to see what's
going on). The implementation also has a informative "up-to-date" [http://
www.olsr.org] web-page with links to mailing lists and papers.
-----------------------------------------------------------------------------
3.1. Installing OLSRd
There are up-to multiple new releases of OLSRd each month, so check the OLSRd
[http://www.olsr.org] web-site for the newest release.
1. The latest release as of this writing is 0.4.3, but by the time you read
this there is almost certain a new release. Fetch the latest release from
[http://www.olsr.org/index.cgi?action=download] http://www.olsr.org/
index.cgi?action=download.
2. Unpack, compile and install the source code:
# tar jxvf uolsrd-x.y.z
# cd unik-olsrd-x.y.z
# make
# make install
3. The olsrd gets installed to /usr/bin/ and a default config file,
olsrd.conf can be found under /etc
Check out the /etc/olsrd.conf config file, and change values to fit your
system. All values in this file can be overridden with command line options
to olsrd. The main options to change are:
# Debug level(0-9)
# If set to 0 the daemon runs in the background
DEBUG 1
# IP version to use (4 or 6)
IPVERSION 6
# A list of whitespace separated interface names
INTERFACES eth1
Later on, when you know OLSRd is configured correctly, you may set "DEBUG"
to 0 to make it run in the background. You may then also add it to your init
scripts. But to test that everything first, set this to at least 1 (setting
this higher will produce a lot more info messages on APM, forwarding, parsing
of the config file etc.)
-----------------------------------------------------------------------------
3.2. Using OLSRd
3.2.1. On one host
When OLSRd is installed and configured, it can be started as root with:
# olsrd
All the settings in /etc/olsrd.conf can be overridden by command line
options:
# olsrd -i eth1 -ipv6 -d 1
Would start olsrd listening on interface eth1 using IPv6 and with debug
messages.
We start olsrd:
# olsrd -i eth1 -d 1 -ipv6
*** UniK olsrd-0.4.3 ***
hello interval = 2.00 hello int nonwireless: = 4.00 (1)
tc interval = 5.00 polling interval = 0.10
neighbor_hold_time = 6.00 neighbor_hold_time_nw = 12.00
topology_hold_time = 15.00 tos setting = 16
hna_interval = 15.00 mid_interval = 5.00
Willingness set to 3 - next update in 20.000000 secs
Using IP version 6
Using multicast address ff05::15
---- Interface configuration ----
eth1: (2)
Address: fec0:106:2700::10
Multicast: ff05::15
Interface eth1 set up for use with index 0
Main address: fec0:106:2700::10 (3)
NEIGHBORS: l=linkstate, m=MPR, w=willingness
Thread created - polling every 0.10 seconds (4)
neighbor list: 11:43:17.214807
neighbor list: 11:43:19.194967
neighbor list: 11:43:21.395046
neighbor list: 11:43:23.604800
neighbor list: 11:43:25.694875
(1) This shows all the settings OLSRd is using. You may override these by
either specifying it in the config file (/etc/olsrd.conf) or specify it
at the command line. Read the [http://www.ietf.org/rfc/rfc3626.txt] OLSR
RFC for a description on what all these settings means.
(2) OLSRd found our interface. If you are using OLSRd with multiple
interfaces, "Multiple Interface Declaration" (MID) messages will be
generated.
(3) If you are using OLSRd with multiple interfaces, it will pick the first
interface specified as the "main" address.
(4) Since no other hosts are running OLSRd, this list is empty.
Another thing worth noticing, is that an entry is added to our routing table:
# route -A inet6
Destination: Next Hop Flags Metric Ref Use Iface
...
ff05::15/128 ff05::15 UAC 0 1 1 eth1
...
This is the IPv6 multicast address OLSR is using to talk to other nodes
running OLSR.
-----------------------------------------------------------------------------
3.2.2. Adding other hosts
There is no point in using OLSRd on only one node, so we add some nodes. You
will then see the "neighbor list" gets updated:
neighbor list: 12:55:14.733586
neighbor list: 12:55:18.803585
Willingness for fec0:106:2700::11 changed from 0 to 3 - UPDATING (1)
neighbor list: 12:55:22.763585
fec0:106:2700::11:l=0:m=0:w=3[2hlist:] (2)
neighbor list: 12:55:26.833589
fec0:106:2700::11:l=1:m=0:w=3[2hlist:]
Willingness for fec0:106:2700::12 changed from 0 to 2 - UPDATING (3)
neighbor list: 12:55:30.903585
fec0:106:2700::12:l=0:m=0:w=2[2hlist:]
fec0:106:2700::11:l=1:m=0:w=3[2hlist:]
neighbor list: 12:55:34.863585
fec0:106:2700::12:l=0:m=0:w=2[2hlist:]
fec0:106:2700::11:l=1:m=0:w=3[2hlist:]
neighbor list: 12:55:39.153586
fec0:106:2700::12:l=1:m=0:w=2[2hlist:fec0:106:2700::11:] (4)
fec0:106:2700::11:l=1:m=0:w=3[2hlist:fec0:106:2700::12:] (5)
neighbor list: 12:55:43.443605
fec0:106:2700::12:l=1:m=0:w=2[2hlist:fec0:106:2700::11:]
fec0:106:2700::11:l=1:m=0:w=3[2hlist:fec0:106:2700::12:]
(1) Another node detected (node B). This specifies the willingness of a
node to carry and forward traffic for other nodes. Here the new node
fec0:106:2700::11 is willing to forward traffic. A host with low battery
may not be willing to forward large amount of traffic, - so it will
proclaim a lower willingness value (routing based on powerstatus is
available as a plugin).
(2) The node has been added to our routing table. We can not (yet) reach
any other node by way of this node, since the 2-hop neighbor list (
[2hlist:]) is empty. A 2-hop neighbor is a node heard by a neighbor.
(3) Here is a third node (node C) running OLSRd.
(4) After a short time, when all nodes have been updated and routes
calculated, we may also reach any of the other nodes via the other. The
2-hop neighbor list ([2hlist:]) is populated: We can reach node B via C.
(5) Here we can reach node C via B.
You will also see the routing table is updated with the new hosts:
# route -A inet6
Destination: Next Hop Flags Metric Ref Use Iface
...
fec0:106:2700::11/128 :: UH 1 0 0 eth1
fec0:106:2700::12/128 :: UH 1 0 0 eth1
...
The real beauty of OLSR is when you add a bunch of nodes and move them
around. You can still reach each one of them either directly (if they are
close), or through other nodes.
-----------------------------------------------------------------------------
3.2.3. Movement
When every node can reach every other node, it's no fun. Let's start moving
the nodes, so that node "A" and "B" are out of (radio) range of each other.
So when we move node "A" far enough away so that it can't hear node "C", all
traffic must go through node "B":
[movement]
We move our three nodes so that node A and C must speak through node B to
reach each other.
Tip: Instead of physically moving the nodes around, you can use ip6tables.
You can drop all packet using the MAC-address. You just need to block on one
node:
# ip6tables -A INPUT -m mac --mac-source XX:XX:XX:XX:XX:XX -j DROP
The output from OLSRd on host A is then:
neighbor list: 13:22:35.693587
fec0:106:2700::11:l=1:m=1:w=3[2hlist:fec0:106:2700::12:] (1)
neighbor list: 13:22:40.093588
fec0:106:2700::11:l=1:m=1:w=3[2hlist:fec0:106:2700::12:]
neighbor list: 13:22:44.053594
fec0:106:2700::11:l=1:m=1:w=3[2hlist:fec0:106:2700::12:]
neighbor list: 13:22:48.233594
fec0:106:2700::11:l=1:m=1:w=3[2hlist:fec0:106:2700::12:]
neighbor list: 13:22:52.193605
fec0:106:2700::11:l=1:m=1:w=3[2hlist:fec0:106:2700::12:]
(1) We can reach node B directly, and via node B we can reach node C.
The routing table also gets updated. For node A to reach node C it must go
through node B:
# route -A inet6
Destination: Next Hop Flags Metric Ref Use Iface
...
fec0:106:2700::11/128 :: UH 1 1 0 eth1
fec0:106:2700::12/128 fec0:106:2700::11 UGH 2 0 0 eth1
...
-----------------------------------------------------------------------------
3.3. What about HNA messages?
" In order to provide this capability of injecting external routing
information into an OLSR MANET, a node with such non-MANET interfaces
periodically issues a Host and Network Association (HNA) message, containing
sufficient information for the recipients to construct an appropriate routing
table."
" An example of such a situation could be where a node is equipped with a
fixed network (e.g., an Ethernet) connecting to a larger network as well as a
wireless network interface running OLSR." --- RFC3626: OLSR, section 12 (page
51).
[HNA]
OLSR with a gateway (GW), that sends out HNA messages. All the other nodes
may then be accessing the "Internet"
To have one node, act as a gateway and send out HNA messages, you must
change the HNA6 in /etc/olsrd.conf:
# HNA IPv6 routes
# syntax: netaddr prefix
# Example Internet gateway
HNA6 :: 0
When you start OLSRd, you will see the node is sending out HNA messages
periodically:
...
Sending HNA (48 bytes)...
...
When the other nodes receives a HNA message, they update their routing
table:
# route -A inet6
Destination: Next Hop Flags Metric Ref Use Iface
...
::/0 fec0:106:2700::1 UG 1 0 0 eth1
...
You may also have multiple nodes in a MANET to act as gateways (sending out
HNA messages). Each mobile node then use the nearest gateway.
-----------------------------------------------------------------------------
3.4. Plugin support
As of version 0.4.3 OLSRd also support plugins. Plugins may be used to add
extended functionality in a MANET. If only a subset of the nodes knows how to
interpret the messagetype, it will be forwarded by all the nodes by the
"default forwarding algorithm" (see section 3.4.1 in the [http://ietf.org/rfc
/rfc3626.txt] OLSR RFC). This way certain nodes may add special functionlity
into OLSR.
As of this writing, two example plugins is included in the OLSRd release. One
of these plugins add routing based on powerstatus. If one node has low
battery, it can set its willingness lower and traffic may be routed through
other nodes.
-----------------------------------------------------------------------------
3.5. Optional GUI
OLSRd also has an optional GUI, which can show a list of available nodes
and grab packets. To compile the GUI front end, you must have GTK2. In
unik-olsrd-x.y.z directory do:
# cd front-end
# make
# make install
Note Remember to start OLSRd with the -ipc switch or set IPC-CONNECT yes in /
etc/olsrd.conf to enable the GUI to chat with OLSRd.
To see some examples of the use of GUI, check out [http://www.olsr.org/
index.cgi?action=gui] http://www.olsr.org/index.cgi?action=gui
-----------------------------------------------------------------------------
3.6. Other OLSR implementations
There is also other OLSR implementations, none have gained as much popularity
as OLSRd, and none of them (except [http://qolsr.lri.fr/] QOLSR?) are fully
RFC compliant.
-----------------------------------------------------------------------------
3.6.1. INRIA
INRIA was one of the first(?) implementation of OLSR [http://
hipercom.inria.fr/olsr/#code] http://hipercom.inria.fr/olsr/#code. Their
web-site has not been updated for quite a while, and the OLSR code you can
download only complies to draft-ietf-manet-olsr-03.txt (it's now an RFC).
There is suppose to be another more up-to-date version of INRIA olsr, but I
have not found it. INRIA OLSR does not support IPv6.
-----------------------------------------------------------------------------
3.6.2. NROLSR
The "US Naval Research Laboratory" (NRL) also has an OLSR implementation. It
is written in C++, and has IPv6 support. [http://pf.itd.nrl.navy.mil/projects
/olsr/] http://pf.itd.nrl.navy.mil/projects/olsr/
-----------------------------------------------------------------------------
3.6.3. CRCOLSR
CRCOLSR is a implementation based on the French INRIA code. It is is supposed
to be maintained by "Communication Research Center" (CRC) in Canada. But as
of this writing, there have been no new releases since April 3, 2003. [http:/
/pf.itd.nrl.navy.mil/projects/olsr/] http://pf.itd.nrl.navy.mil/projects/
olsr/
-----------------------------------------------------------------------------
3.6.4. QOLSR
QOLSR is aiming to provide "Quality of Service" routing in wireless mobile ad
hoc networks. There is no QoS support at the time of this writing, and
support for ipv4/ipv6 is triggered at compile time. Written in C++.
-----------------------------------------------------------------------------
4. FAQ
Some of these question/answers are from the [http://www.olsr.org] OLSRd site.
4.1. If OLSRd fully RFC3626 compliant?
4.2. Can I mix site-local and global IPv6 addresses?
4.3. The GUI front-end failed to compile...why?
4.4. If there is multiply gateways present, how does the mobile node conclude
to use the nearest one?
4.5. I get OLSRd up and running - but the nodes don't seem to "hear" each
other!
4.1. If OLSRd fully RFC3626 compliant?
Yes. It even has implemented some of the extra functionality mentioned in the
RFC. See the [http://www.olsr.org/index.cgi?action=comp] RFC Compliance
section for complete list.
4.2. Can I mix site-local and global IPv6 addresses?
Yes. But keep in mind that they intentionally were not designed to be used at
the same time. The network topology can be quite "messy" if you start using
these two.
4.3. The GUI front-end failed to compile...why?
You probably don't have the GTK2.0 development libraries installed.
4.4. If there is multiply gateways present, how does the mobile node conclude
to use the nearest one?
When a new gateway is detected, the Mobile Node checks the distance (number
of hops) to this newly discovered gateway compared to the current gateway. If
there is a shorter distance, this new gateway becomes the current (default)
gateway. See section 12.6.2 in the OLSR RFC ([http://www.ietf.org/rfc/
rfc3626.txt] RFC3626)
4.5. I get OLSRd up and running - but the nodes don't seem to "hear" each
other!
Most of the time this is a configuration error: Check the following:
<EFBFBD><EFBFBD>*<2A> If using WLAN interfaces make sure the ESSID/key match.
<EFBFBD><EFBFBD>*<2A> Make sure the cards are set in "ad-hoc" mode and not "managed".
<EFBFBD><EFBFBD>*<2A> Make sure you are not blocking UDP/698. If using netfilter run
ip6tables -L as root to see what rules are set. ip6tables -F flushes all
rules.
-----------------------------------------------------------------------------
5. Useful Resources
1. OLSRd (old uOLSR)[http://www.olsr.org] http://www.olsr.org
2. Optimized Link State Routing Protocol (OLSR) RFC3626[http://www.ietf.org/
rfc/rfc3626.txt] http://www.ietf.org/rfc/rfc3626.txt
3. Mobile Ad hoc Networking (MANET) RFC2501[http://www.ietf.org/rfc/
rfc2501.txt] http://www.ietf.org/rfc/rfc3626.txt
4. Mobile Ad-hoc Networks (manet) Working Group (IETF)[http://www.ietf.org/
html.charters/manet-charter.html] http://www.ietf.org/html.charters/
manet-charter.html
5. Open Shortest Path First IGP (ospf)[http://www.ietf.org/html.charters/
ospf-charter.html] http://www.ietf.org/html.charters/ospf-charter.html
6. Protean Forge - OLSR software (CRC and NRL) [http://pf.itd.nrl.navy.mil/
projects/olsr/] http://pf.itd.nrl.navy.mil/projects/olsr/
7. INRIA OLSR [http://hipercom.inria.fr/olsr/] http://hipercom.inria.fr/
olsr/
8. QOLSR [http://qolsr.lri.fr/] http://qolsr.lri.fr/
9. IPv6 Working Group (IETF) [http://www.ietf.org/html.charters/
ipv6-charter.html] http://www.ietf.org/html.charters/ipv6-charter.html
10. RFC2460 Internet Protocol, Version 6 (IPv6) Specification [http://
www.ietf.org/rfc/rfc2460.txt] http://www.ietf.org/rfc/rfc2460.txt
11. Peter Bieringer's Linux IPv6 HOWTO (en) [http://ldp.linux.no/HOWTO/
Linux+IPv6-HOWTO/] http://ldp.linux.no/HOWTO/Linux+IPv6-HOWTO/
12. Current Status of IPv6 Support for Networking Applications [http://
www.deepspace6.net/docs/ipv6_status_page_apps.html] http://
www.deepspace6.net/docs/ipv6_status_page_apps.html
-----------------------------------------------------------------------------
6. Copyright, acknowledgments and miscellaneous
6.1. Copyright and License
Copyright (c) 2003, 2004 Lars Strand.
Permission is granted to copy, distribute and/or modify this document under
the terms of the GNU Free Documentation License, Version 1.2 or any later
version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the
license is included in the section entitled "GNU Free Documentation License".
-----------------------------------------------------------------------------
6.2. How this document was produced
This document was originally written in LaTeX using Emacs. HTML version
created with latex2html. Later it was converted to DocBook XML.
An up-to-date version of this document can be found at:
HTML: [http://www.tldp.org/HOWTO/OLSR-IPv6-HOWTO/index.html] http://
www.tldp.org/HOWTO/OLSR-IPv6-HOWTO/index.html
-----------------------------------------------------------------------------
6.3. Feedback
Suggestions, corrections, additions wanted. Contributors wanted and
acknowledged. Flames not wanted.
I can always be reached at <lars at unik no>
Homepage: [http://www.gnist.org/~lars/] http://www.gnist.org/~lars/
-----------------------------------------------------------------------------
6.4. Acknowledgments
This document was produced as a part of Interoperable Networks for Secure
Communications [http://insc.nodeca.mil.no/] (INSC task 6)
Thanks to Andreas Hafslund (andreha [at] unik no) for initial support. Also
thanks to UniK (University Graduate Center) [http://www.unik.no] http://
www.unik.no and FFI (Norwegian Defence Research Establishment) [http://
www.ffi.mil.no] http://www.ffi.mil.no for hardware support.
Also thanks to Andreas T<>nnesen (andreto [at] unik no) for technical help
updating this howto
Thanks also to the other HOWTO authors whose works I have referenced:
Linux IPv6 HOWTO (en) by Peter Bieringer
-----------------------------------------------------------------------------
A. GNU Free Documentation License
Version 1.2, November 2002
Copyright (C) 2000,2001,2002 Free Software Foundation, Inc. 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA Everyone is permitted to copy
and distribute verbatim copies of this license document, but changing it
is not allowed.
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A.1. PREAMBLE
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.
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A.2. 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.
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A.3. 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.
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A.4. 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.
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A.5. MODIFICATIONS
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.
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A.6. 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".
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A.7. 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.
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A.8. 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.
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A.9. TRANSLATION
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.
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A.10. TERMINATION
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.
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A.11. 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.
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A.12. ADDENDUM: How to use this License for your documents
To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license notices
just after the title page:
Copyright (c) YEAR YOUR NAME. Permission is granted to copy, distribute
and/or modify this document under the terms of the GNU Free Documentation
License, Version 1.2 or any later version published by the Free Software
Foundation; with no Invariant Sections, no Front-Cover Texts, and no
Back-Cover Texts. A copy of the license is included in the section
entitled "GNU Free Documentation License".
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the "with...Texts." line with this:
with the Invariant Sections being LIST THEIR TITLES, with the
Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
If you have Invariant Sections without Cover Texts, or some other combination
of the three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend
releasing these examples in parallel under your choice of free software
license, such as the GNU General Public License, to permit their use in free
software.
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