+ <item>
+ <title>Teaching vmdebootstrap to create Raspberry Pi SD card images</title>
+ <link>http://people.skolelinux.org/pere/blog/Teaching_vmdebootstrap_to_create_Raspberry_Pi_SD_card_images.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Teaching_vmdebootstrap_to_create_Raspberry_Pi_SD_card_images.html</guid>
+ <pubDate>Sun, 27 Oct 2013 17:00:00 +0100</pubDate>
+ <description><p>The
+<a href="http://packages.qa.debian.org/v/vmdebootstrap.html">vmdebootstrap</a>
+program is a a very nice system to create virtual machine images. It
+create a image file, add a partition table, mount it and run
+debootstrap in the mounted directory to create a Debian system on a
+stick. Yesterday, I decided to try to teach it how to make images for
+<a href="https://wiki.debian.org/RaspberryPi">Raspberry Pi</a>, as part
+of a plan to simplify the build system for
+<a href="https://wiki.debian.org/FreedomBox">the FreedomBox
+project</a>. The FreedomBox project already uses vmdebootstrap for
+the virtualbox images, but its current build system made multistrap
+based system for Dreamplug images, and it is lacking support for
+Raspberry Pi.</p>
+
+<p>Armed with the knowledge on how to build "foreign" (aka non-native
+architecture) chroots for Raspberry Pi, I dived into the vmdebootstrap
+code and adjusted it to be able to build armel images on my amd64
+Debian laptop. I ended up giving vmdebootstrap five new options,
+allowing me to replicate the image creation process I use to make
+<a href="http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html">Debian
+Jessie based mesh node images for the Raspberry Pi</a>. First, the
+<tt>--foreign /path/to/binfm_handler</tt> option tell vmdebootstrap to
+call debootstrap with --foreign and to copy the handler into the
+generated chroot before running the second stage. This allow
+vmdebootstrap to create armel images on an amd64 host. Next I added
+two new options <tt>--bootsize size</tt> and <tt>--boottype
+fstype</tt> to teach it to create a separate /boot/ partition with the
+given file system type, allowing me to create an image with a vfat
+partition for the /boot/ stuff. I also added a <tt>--variant
+variant</tt> option to allow me to create smaller images without the
+Debian base system packages installed. Finally, I added an option
+<tt>--no-extlinux</tt> to tell vmdebootstrap to not install extlinux
+as a boot loader. It is not needed on the Raspberry Pi and probably
+most other non-x86 architectures. The changes were accepted by the
+upstream author of vmdebootstrap yesterday and today, and is now
+available from
+<a href="http://git.liw.fi/cgi-bin/cgit/cgit.cgi/vmdebootstrap/">the
+upstream project page</a>.</p>
+
+<p>To use it to build a Raspberry Pi image using Debian Jessie, first
+create a small script (the customize script) to add the non-free
+binary blob needed to boot the Raspberry Pi and the APT source
+list:</p>
+
+<p><pre>
+#!/bin/sh
+set -e # Exit on first error
+rootdir="$1"
+cd "$rootdir"
+cat &lt;&lt;EOF > etc/apt/sources.list
+deb http://http.debian.net/debian/ jessie main contrib non-free
+EOF
+# Install non-free binary blob needed to boot Raspberry Pi. This
+# install a kernel somewhere too.
+wget https://raw.github.com/Hexxeh/rpi-update/master/rpi-update \
+ -O $rootdir/usr/bin/rpi-update
+chmod a+x $rootdir/usr/bin/rpi-update
+mkdir -p $rootdir/lib/modules
+touch $rootdir/boot/start.elf
+chroot $rootdir rpi-update
+</pre></p>
+
+<p>Next, fetch the latest vmdebootstrap script and call it like this
+to build the image:</p>
+
+<pre>
+sudo ./vmdebootstrap \
+ --variant minbase \
+ --arch armel \
+ --distribution jessie \
+ --mirror http://http.debian.net/debian \
+ --image test.img \
+ --size 600M \
+ --bootsize 64M \
+ --boottype vfat \
+ --log-level debug \
+ --verbose \
+ --no-kernel \
+ --no-extlinux \
+ --root-password raspberry \
+ --hostname raspberrypi \
+ --foreign /usr/bin/qemu-arm-static \
+ --customize `pwd`/customize \
+ --package netbase \
+ --package git-core \
+ --package binutils \
+ --package ca-certificates \
+ --package wget \
+ --package kmod
+</pre></p>
+
+<p>The list of packages being installed are the ones needed by
+rpi-update to make the image bootable on the Raspberry Pi, with the
+exception of netbase, which is needed by debootstrap to find
+/etc/hosts with the minbase variant. I really wish there was a way to
+set up an Raspberry Pi using only packages in the Debian archive, but
+that is not possible as far as I know, because it boots from the GPU
+using a non-free binary blob.</p>
+
+<p>The build host need debootstrap, kpartx and qemu-user-static and
+probably a few others installed. I have not checked the complete
+build dependency list.</p>
+
+<p>The resulting image will not use the hardware floating point unit
+on the Raspberry PI, because the armel architecture in Debian is not
+optimized for that use. So the images created will be a bit slower
+than <a href="http://www.raspbian.org/">Raspbian</a> based images.</p>
+</description>
+ </item>
+
+ <item>
+ <title>Det er jo makta som er mest sårbar ved massiv overvåkning av Internett</title>
+ <link>http://people.skolelinux.org/pere/blog/Det_er_jo_makta_som_er_mest_s_rbar_ved_massiv_overv_kning_av_Internett.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Det_er_jo_makta_som_er_mest_s_rbar_ved_massiv_overv_kning_av_Internett.html</guid>
+ <pubDate>Sat, 26 Oct 2013 20:30:00 +0200</pubDate>
+ <description><p>De siste måneders eksponering av
+<a href="http://www.aftenposten.no/nyheter/uriks/Her-er-Edvard-Snowdens-mest-omtalte-avsloringer-7351734.html">den
+totale overvåkningen som foregår i den vestlige verden dokumenterer
+hvor sårbare vi er</a>. Men det slår meg at de som er mest sårbare
+for dette, myndighetspersoner på alle nivåer, neppe har innsett at de
+selv er de mest interessante personene å lage profiler på, for å kunne
+påvirke dem.</p>
+
+<p>For å ta et lite eksempel: Stortingets nettsted,
+<a href="http://www.stortinget.no/">www.stortinget.no</a> (og
+forsåvidt også
+<a href="http://data.stortinget.no/">data.stortinget.no</a>),
+inneholder informasjon om det som foregår på Stortinget, og jeg antar
+de største brukerne av informasjonen der er representanter og
+rådgivere på Stortinget. Intet overraskende med det. Det som derimot
+er mer skjult er at Stortingets nettsted bruker
+<a href="http://en.wikipedia.org/wiki/Google_Analytics">Google
+Analytics</a>, hvilket gjør at enhver som besøker nettsidene der også
+rapporterer om besøket via Internett-linjer som passerer Sverige,
+England og videre til USA. Det betyr at informasjon om ethvert besøk
+på stortingets nettsider kan snappes opp av svensk, britisk og USAs
+etterretningsvesen. De kan dermed holde et øye med hvilke
+Stortingssaker stortingsrepresentantene synes er interessante å sjekke
+ut, og hvilke sider rådgivere og andre på stortinget synes er
+interessant å besøke, når de gjør det og hvilke andre representanter
+som sjekker de samme sidene omtrent samtidig. Stortingets bruk av
+Google Analytics gjør det dermed enkelt for utenlands etteretning å
+spore representantenes aktivitet og interesse. Hvis noen av
+representantene bruker Google Mail eller noen andre tjenestene som
+krever innlogging, så vil det være enda enklere å finne ut nøyaktig
+hvilke personer som bruker hvilke nettlesere og dermed knytte
+informasjonen opp til enkeltpersoner på Stortinget.</p>
+
+<p>Og jo flere nettsteder som bruker Google Analytics, jo bedre
+oversikt over stortingsrepresentantenes lesevaner og interesse blir
+tilgjengelig for svensk, britisk og USAs etterretning. Hva de kan
+bruke den informasjonen til overlater jeg til leseren å undres
+over.</p>
+</description>
+ </item>
+
+ <item>
+ <title>A Raspberry Pi based batman-adv Mesh network node</title>
+ <link>http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</guid>
+ <pubDate>Mon, 21 Oct 2013 11:40:00 +0200</pubDate>
+ <description><p>The last few days I have been experimenting with
+<a href="http://www.open-mesh.org/projects/batman-adv/wiki">the
+batman-adv mesh technology</a>. I want to gain some experience to see
+if it will fit <a href="https://wiki.debian.org/FreedomBox">the
+Freedombox project</a>, and together with my neighbors try to build a
+mesh network around the park where I live. Batman-adv is a layer 2
+mesh system ("ethernet" in other words), where the mesh network appear
+as if all the mesh clients are connected to the same switch.</p>
+
+<p>My hardware of choice was the Linksys WRT54GL routers I had lying
+around, but I've been unable to get them working with batman-adv. So
+instead, I started playing with a
+<a href="http://www.raspberrypi.org/">Raspberry Pi</a>, and tried to
+get it working as a mesh node. My idea is to use it to create a mesh
+node which function as a switch port, where everything connected to
+the Raspberry Pi ethernet plug is connected (bridged) to the mesh
+network. This allow me to hook a wifi base station like the Linksys
+WRT54GL to the mesh by plugging it into a Raspberry Pi, and allow
+non-mesh clients to hook up to the mesh. This in turn is useful for
+Android phones using <a href="http://servalproject.org/">the Serval
+Project</a> voip client, allowing every one around the playground to
+phone and message each other for free. The reason is that Android
+phones do not see ad-hoc wifi networks (they are filtered away from
+the GUI view), and can not join the mesh without being rooted. But if
+they are connected using a normal wifi base station, they can talk to
+every client on the local network.</p>
+
+<p>To get this working, I've created a debian package
+<a href="https://github.com/petterreinholdtsen/meshfx-node">meshfx-node</a>
+and a script
+<a href="https://github.com/petterreinholdtsen/meshfx-node/blob/master/build-rpi-mesh-node">build-rpi-mesh-node</a>
+to create the Raspberry Pi boot image. I'm using Debian Jessie (and
+not Raspbian), to get more control over the packages available.
+Unfortunately a huge binary blob need to be inserted into the boot
+image to get it booting, but I'll ignore that for now. Also, as
+Debian lack support for the CPU features available in the Raspberry
+Pi, the system do not use the hardware floating point unit. I hope
+the routing performance isn't affected by the lack of hardware FPU
+support.</p>
+
+<p>To create an image, run the following with a sudo enabled user
+after inserting the target SD card into the build machine:</p>
+
+<p><pre>
+% wget -O build-rpi-mesh-node \
+ https://raw.github.com/petterreinholdtsen/meshfx-node/master/build-rpi-mesh-node
+% sudo bash -x ./build-rpi-mesh-node > build.log 2>&1
+% dd if=/root/rpi/rpi_basic_jessie_$(date +%Y%m%d).img of=/dev/mmcblk0 bs=1M
+%
+</pre></p>
+
+<p>Booting with the resulting SD card on a Raspberry PI with a USB
+wifi card inserted should give you a mesh node. At least it does for
+me with a the wifi card I am using. The default mesh settings are the
+ones used by the Oslo mesh project at Hackeriet, as I mentioned in
+<a href="http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html">an
+earlier blog post about this mesh testing</a>.</p>
+
+<p>The mesh node was not horribly expensive either. I bought
+everything over the counter in shops nearby. If I had ordered online
+from the lowest bidder, the price should be significantly lower:</p>
+
+<p><table>
+
+<tr><th>Supplier</th><th>Model</th><th>NOK</th></tr>
+<tr><td>Teknikkmagasinet</td><td>Raspberry Pi model B</td><td>349.90</td></tr>
+<tr><td>Teknikkmagasinet</td><td>Raspberry Pi type B case</td><td>99.90</td></tr>
+<tr><td>Lefdal</td><td>Jensen Air:Link 25150</td><td>295.-</td></tr>
+<tr><td>Clas Ohlson</td><td>Kingston 16 GB SD card</td><td>199.-</td></tr>
+<tr><td>Total cost</td><td></td><td>943.80</td></tr>
+
+</table></p>
+
+<p>Now my mesh network at home consist of one laptop in the basement
+connected to my production network, one Raspberry Pi node on the 1th
+floor that can be seen by my neighbor across the park, and one
+play-node I use to develop the image building script. And some times
+I hook up my work horse laptop to the mesh to test it. I look forward
+to figuring out what kind of latency the batman-adv setup will give,
+and how much packet loss we will experience around the park. :)</p>
+</description>
+ </item>
+
+ <item>
+ <title>Perl library to control the Spykee robot moved to github</title>
+ <link>http://people.skolelinux.org/pere/blog/Perl_library_to_control_the_Spykee_robot_moved_to_github.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Perl_library_to_control_the_Spykee_robot_moved_to_github.html</guid>
+ <pubDate>Sat, 19 Oct 2013 10:20:00 +0200</pubDate>
+ <description><p>Back in 2010, I created a Perl library to talk to
+<a href="http://en.wikipedia.org/wiki/Spykee">the Spykee robot</a>
+(with two belts, wifi, USB and Linux) and made it available from my
+web page. Today I concluded that it should move to a site that is
+easier to use to cooperate with others, and moved it to github. If
+you got a Spykee robot, you might want to check out
+<a href="https://github.com/petterreinholdtsen/libspykee-perl">the
+libspykee-perl github repository</a>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>Good causes: Debian Outreach Program for Women, EFF documenting the spying and Open access in Norway</title>
+ <link>http://people.skolelinux.org/pere/blog/Good_causes__Debian_Outreach_Program_for_Women__EFF_documenting_the_spying_and_Open_access_in_Norway.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Good_causes__Debian_Outreach_Program_for_Women__EFF_documenting_the_spying_and_Open_access_in_Norway.html</guid>
+ <pubDate>Tue, 15 Oct 2013 21:30:00 +0200</pubDate>
+ <description><p>The last few days I came across a few good causes that should get
+wider attention. I recommend signing and donating to each one of
+these. :)</p>
+
+<p>Via <a href="http://www.debian.org/News/weekly/2013/18/">Debian
+Project News for 2013-10-14</a> I came across the Outreach Program for
+Women program which is a Google Summer of Code like initiative to get
+more women involved in free software. One debian sponsor has offered
+to match <a href="http://debian.ch/opw2013">any donation done to Debian
+earmarked</a> for this initiative. I donated a few minutes ago, and
+hope you will to. :)</p>
+
+<p>And the Electronic Frontier Foundation just announced plans to
+create <a href="https://supporters.eff.org/donate/nsa-videos">video
+documentaries about the excessive spying</a> on every Internet user that
+take place these days, and their need to fund the work. I've already
+donated. Are you next?</p>
+
+<p>For my Norwegian audience, the organisation Studentenes og
+Akademikernes Internasjonale Hjelpefond is collecting signatures for a
+statement under the heading
+<a href="http://saih.no/Bloggers_United/">Bloggers United for Open
+Access</a> for those of us asking for more focus on open access in the
+Norwegian government. So far 499 signatures. I hope you will sign it
+too.</p>
+</description>
+ </item>
+
+ <item>
+ <title>Oslo community mesh network - with NUUG and Hackeriet at Hausmania</title>
+ <link>http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</guid>
+ <pubDate>Fri, 11 Oct 2013 14:10:00 +0200</pubDate>
+ <description><p>Wireless mesh networks are self organising and self healing
+networks that can be used to connect computers across small and large
+areas, depending on the radio technology used. Normal wifi equipment
+can be used to create home made radio networks, and there are several
+successful examples like
+<a href="http://www.freifunk.net/">Freifunk</a> and
+<a href="http://www.awmn.net/">Athens Wireless Metropolitan Network</a>
+(see
+<a href="http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region#Greece">wikipedia
+for a large list</a>) around the globe. To give you an idea how it
+work, check out the nice overview of the Kiel Freifunk community which
+can be seen from their
+<a href="http://freifunk.in-kiel.de/ffmap/nodes.html">dynamically
+updated node graph and map</a>, where one can see how the mesh nodes
+automatically handle routing and recover from nodes disappearing.
+There is also a small community mesh network group in Oslo, Norway,
+and that is the main topic of this blog post.</p>
+
+<p>I've wanted to check out mesh networks for a while now, and hoped
+to do it as part of my involvement with the <a
+href="http://www.nuug.no/">NUUG member organisation</a> community, and
+my recent involvement in
+<a href="https://wiki.debian.org/FreedomBox">the Freedombox project</a>
+finally lead me to give mesh networks some priority, as I suspect a
+Freedombox should use mesh networks to connect neighbours and family
+when possible, given that most communication between people are
+between those nearby (as shown for example by research on Facebook
+communication patterns). It also allow people to communicate without
+any central hub to tap into for those that want to listen in on the
+private communication of citizens, which have become more and more
+important over the years.</p>
+
+<p>So far I have only been able to find one group of people in Oslo
+working on community mesh networks, over at the hack space
+<a href="http://hackeriet.no/">Hackeriet</a> at Husmania. They seem to
+have started with some Freifunk based effort using OLSR, called
+<a href="http://oslo.freifunk.net/index.php?title=Main_Page">the Oslo
+Freifunk project</a>, but that effort is now dead and the people
+behind it have moved on to a batman-adv based system called
+<a href="http://meshfx.org/trac">meshfx</a>. Unfortunately the wiki
+site for the Oslo Freifunk project is no longer possible to update to
+reflect this fact, so the old project page can't be updated to point to
+the new project. A while back, the people at Hackeriet invited people
+from the Freifunk community to Oslo to talk about mesh networks. I
+came across this video where Hans Jørgen Lysglimt interview the
+speakers about this talk (from
+<a href="https://www.youtube.com/watch?v=N2Kd7CLkhSY">youtube</a>):</p>
+
+<p><iframe width="420" height="315" src="https://www.youtube.com/embed/N2Kd7CLkhSY" frameborder="0" allowfullscreen></iframe></p>
+
+<p>I mentioned OLSR and batman-adv, which are mesh routing protocols.
+There are heaps of different protocols, and I am still struggling to
+figure out which one would be "best" for some definitions of best, but
+given that the community mesh group in Oslo is so small, I believe it
+is best to hook up with the existing one instead of trying to create a
+completely different setup, and thus I have decided to focus on
+batman-adv for now. It sure help me to know that the very cool
+<a href="http://www.servalproject.org/">Serval project in Australia</a>
+is using batman-adv as their meshing technology when it create a self
+organizing and self healing telephony system for disaster areas and
+less industrialized communities. Check out this cool video presenting
+that project (from
+<a href="https://www.youtube.com/watch?v=30qNfzJCQOA">youtube</a>):</p>
+
+<p><iframe width="560" height="315" src="https://www.youtube.com/embed/30qNfzJCQOA" frameborder="0" allowfullscreen></iframe></p>
+
+<p>According to the wikipedia page on
+<a href="http://en.wikipedia.org/wiki/Wireless_mesh_network">Wireless
+mesh network</a> there are around 70 competing schemes for routing
+packets across mesh networks, and OLSR, B.A.T.M.A.N. and
+B.A.T.M.A.N. advanced are protocols used by several free software
+based community mesh networks.</p>
+
+<p>The batman-adv protocol is a bit special, as it provide layer 2
+(as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same
+network. One way to think about it is that it provide a mesh based
+vlan you can bridge to or handle like any other vlan connected to your
+computer. The required drivers are already in the Linux kernel at
+least since Debian Wheezy, and it is fairly easy to set up. A
+<a href="http://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide">good
+introduction</a> is available from the Open Mesh project. These are
+the key settings needed to join the Oslo meshfx network:</p>
+
+<p><table>
+<tr><th>Setting</th><th>Value</th></tr>
+<tr><td>Protocol / kernel module</td><td>batman-adv</td></tr>
+<tr><td>ESSID</td><td>meshfx@hackeriet</td></tr>
+<td>Channel / Frequency</td><td>11 / 2462</td></tr>
+<td>Cell ID</td><td>02:BA:00:00:00:01</td>
+</table></p>
+
+<p>The reason for setting ad-hoc wifi Cell ID is to work around bugs
+in firmware used in wifi card and wifi drivers. (See a nice post from
+VillageTelco about
+"<a href="http://tiebing.blogspot.no/2009/12/ad-hoc-cell-splitting-re-post-original.html">Information
+about cell-id splitting, stuck beacons, and failed IBSS merges!</a>
+for details.) When these settings are activated and you have some
+other mesh node nearby, your computer will be connected to the mesh
+network and can communicate with any mesh node that is connected to
+any of the nodes in your network of nodes. :)</p>
+
+<p>My initial plan was to reuse my old Linksys WRT54GL as a mesh node,
+but that seem to be very hard, as I have not been able to locate a
+firmware supporting batman-adv. If anyone know how to use that old
+wifi access point with batman-adv these days, please let me know.</p>
+
+<p>If you find this project interesting and want to join, please join
+us on IRC, either channel
+<a href="irc://irc.freenode.net/#oslohackerspace">#oslohackerspace</a>
+or <a href="irc://irc.freenode.net/#nuug">#nuug</a> on
+irc.freenode.net.</p>
+
+<p>While investigating mesh networks in Oslo, I came across an old
+research paper from the university of Stavanger and Telenor Research
+and Innovation called
+<a href="http://folk.uio.no/paalee/publications/netrel-egeland-iswcs-2008.pdf">The
+reliability of wireless backhaul mesh networks</a> and elsewhere
+learned that Telenor have been experimenting with mesh networks at
+Grünerløkka in Oslo. So mesh networks are also interesting for
+commercial companies, even though Telenor discovered that it was hard
+to figure out a good business plan for mesh networking and as far as I
+know have closed down the experiment. Perhaps Telenor or others would
+be interested in a cooperation?</p>
+
+<p><strong>Update 2013-10-12</strong>: I was just
+<a href="http://lists.alioth.debian.org/pipermail/freedombox-discuss/2013-October/005900.html">told
+by the Serval project developers</a> that they no longer use
+batman-adv (but are compatible with it), but their own crypto based
+mesh system.</p>
+</description>
+ </item>
+
projects / homepage.git / blobdiff