blog/archive/2013/10/10.rss

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   3         <channel>
   4                 <title>Petter Reinholdtsen - Entries from October 2013</title>
   5                 <description>Entries from October 2013</description>
   6                 <link>http://people.skolelinux.org/pere/blog/</link>
   7
   8
   9         <item>
  10                 <title>A Raspberry Pi based batman-adv Mesh network node</title>
  11                 <link>http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</link>
  12                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/A_Raspberry_Pi_based_batman_adv_Mesh_network_node.html</guid>
  13                 <pubDate>Mon, 21 Oct 2013 11:40:00 +0200</pubDate>
  14                 <description>&lt;p&gt;The last few days I have been experimenting with
  15 &lt;a href=&quot;http://www.open-mesh.org/projects/batman-adv/wiki&quot;&gt;the
  16 batman-adv mech technology&lt;/a&gt;.  I want to gain some experience to see
  17 if it will fit &lt;a href=&quot;https://wiki.debian.org/FreedomBox&quot;&gt;the
  18 Freedombox project&lt;/a&gt;, and together with my neighbors try to build a
  19 mesh network around the park where I live.  Batman-adv is a layer 2
  20 mesh system (&quot;ethernet&quot; in other words), where the mesh network appear
  21 as if all the mesh clients are connected to the same switch.&lt;/p&gt;
  22
  23 &lt;p&gt;My hardware of choice was the Linksys WRT54GL routers I had lying
  24 around, but I&#39;ve been unable to get them working with batman-adv.  So
  25 instead, I started playing with a
  26 &lt;a href=&quot;http://www.raspberrypi.org/&quot;&gt;Raspberry Pi&lt;/a&gt;, and tried to
  27 get it working as a mesh node.  My idea is to use it to create a mesh
  28 node which function as a switch port, where everything connected to
  29 the Raspberry Pi ethernet plug is connected (bridged) to the mesh
  30 network.  This allow me to hook a wifi base station like the Linksys
  31 WRT54GL to the mesh by plugging it into a Raspberry Pi, and allow
  32 non-mesh clients to hook up to the mesh.  This in turn is useful for
  33 Android phones using &lt;a href=&quot;http://servalproject.org/&quot;&gt;the Serval
  34 Project&lt;/a&gt; voip client, allowing every one around the playground to
  35 phone and message each other for free.  The reason is that Android
  36 phones do not see ad-hoc wifi networks (they are filtered away from
  37 the GUI view), and can not join the mesh without being rooted.  But if
  38 they are connected using a normal wifi base station, they can talk to
  39 every client on the local network.&lt;/p&gt;
  40
  41 &lt;p&gt;To get this working, I&#39;ve created a debian package
  42 &lt;a href=&quot;https://github.com/petterreinholdtsen/meshfx-node&quot;&gt;meshfx-node&lt;/a&gt;
  43 and a script
  44 &lt;a href=&quot;https://github.com/petterreinholdtsen/meshfx-node/blob/master/build-rpi-mesh-node&quot;&gt;build-rpi-mesh-node&lt;/a&gt;
  45 to create the Raspberry Pi boot image.  I&#39;m using Debian Jessie (and
  46 not Raspbian), to get more control over the packages available.
  47 Unfortunately a huge binary blob need to be inserted into the boot
  48 image to get it booting, but I&#39;ll ignore that for now.  Also, as
  49 Debian lack support for the CPU features available in the Raspberry
  50 Pi, the system do not use the hardware floating point unit.  I hope
  51 the routing performance isn&#39;t affected by the lack of hardware FPU
  52 support.&lt;/p&gt;
  53
  54 &lt;p&gt;To create an image, run the following with a sudo enabled user
  55 after inserting the target SD card into the build machine:&lt;/p&gt;
  56
  57 &lt;p&gt;&lt;pre&gt;
  58 % wget -O build-rpi-mesh-node \
  59     https://raw.github.com/petterreinholdtsen/meshfx-node/master/build-rpi-mesh-node
  60 % sudo bash -x ./build-rpi-mesh-node &gt; build.log 2&gt;&amp;1
  61 % dd if=/root/rpi/rpi_basic_jessie_$(date +%Y%m%d).img of=/dev/mmcblk0 bs=1M
  62 %
  63 &lt;/pre&gt;&lt;/p&gt;
  64
  65 &lt;p&gt;Booting with the resulting SD card on a Raspberry PI with a USB
  66 wifi card inserted should give you a mesh node.  At least it does for
  67 me with a the wifi card I am using. The default mesh settings are the
  68 ones used by the Oslo mesh project at Hackeriet, as I mentioned in
  69 &lt;a href=&quot;http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html&quot;&gt;an
  70 earlier blog post about this mesh testing&lt;/a&gt;.&lt;/p&gt;
  71
  72 &lt;p&gt;The mesh node was not horribly expensive either.  I bought
  73 everything over the counter in shops nearby.  If I had ordered online
  74 from the lowest bidder, the price should be significantly lower:&lt;/p&gt;
  75
  76 &lt;p&gt;&lt;table&gt;
  77
  78 &lt;tr&gt;&lt;th&gt;Supplier&lt;/th&gt;&lt;th&gt;Model&lt;/th&gt;&lt;th&gt;NOK&lt;/th&gt;&lt;/tr&gt;
  79 &lt;tr&gt;&lt;td&gt;Teknikkmagasinet&lt;/td&gt;&lt;td&gt;Raspberry Pi model B&lt;/td&gt;&lt;td&gt;349.90&lt;/td&gt;&lt;/tr&gt;
  80 &lt;tr&gt;&lt;td&gt;Teknikkmagasinet&lt;/td&gt;&lt;td&gt;Raspberry Pi type B case&lt;/td&gt;&lt;td&gt;99.90&lt;/td&gt;&lt;/tr&gt;
  81 &lt;tr&gt;&lt;td&gt;Lefdal&lt;/td&gt;&lt;td&gt;Jensen Air:Link 25150&lt;/td&gt;&lt;td&gt;295.-&lt;/td&gt;&lt;/tr&gt;
  82 &lt;tr&gt;&lt;td&gt;Clas Ohlson&lt;/td&gt;&lt;td&gt;Kingston 16 GB SD card&lt;/td&gt;&lt;td&gt;199.-&lt;/td&gt;&lt;/tr&gt;
  83 &lt;tr&gt;&lt;td&gt;Total cost&lt;/td&gt;&lt;td&gt;&lt;/td&gt;&lt;td&gt;943.80&lt;/td&gt;&lt;/tr&gt;
  84
  85 &lt;/table&gt;&lt;/p&gt;
  86
  87 &lt;p&gt;Now my mesh network at home consist of one laptop in the basement
  88 connected to my production network, one Raspberry Pi node on the 1th
  89 floor that can be seen by my neighbor across the park, and one
  90 play-node I use to develop the image building script.  And some times
  91 I hook up work horse laptop to the mesh to test it.  I look forward to
  92 figuring out what kind of latency the batman-adv setup will give, and
  93 how much packet loss we will experience around the park. :)&lt;/p&gt;
  94 </description>
  95         </item>
  96
  97         <item>
  98                 <title>Perl library to control the Spykee robot moved to github</title>
  99                 <link>http://people.skolelinux.org/pere/blog/Perl_library_to_control_the_Spykee_robot_moved_to_github.html</link>
 100                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Perl_library_to_control_the_Spykee_robot_moved_to_github.html</guid>
 101                 <pubDate>Sat, 19 Oct 2013 10:20:00 +0200</pubDate>
 102                 <description>&lt;p&gt;Back in 2010, I created a Perl library to talk to
 103 &lt;a href=&quot;http://en.wikipedia.org/wiki/Spykee&quot;&gt;the Spykee robot&lt;/a&gt;
 104 (with two belts, wifi, USB and Linux) and made it available from my
 105 web page.  Today I concluded that it should move to a site that is
 106 easier to use to cooperate with others, and moved it to github.  If
 107 you got a Spykee robot, you might want to check out
 108 &lt;a href=&quot;https://github.com/petterreinholdtsen/libspykee-perl&quot;&gt;the
 109 libspykee-perl github repository&lt;/a&gt;.&lt;/p&gt;
 110 </description>
 111         </item>
 112
 113         <item>
 114                 <title>Good causes: Debian Outreach Program for Women, EFF documenting the spying and Open access in Norway</title>
 115                 <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>
 116                 <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>
 117                 <pubDate>Tue, 15 Oct 2013 21:30:00 +0200</pubDate>
 118                 <description>&lt;p&gt;The last few days I came across a few good causes that should get
 119 wider attention.  I recommend signing and donating to each one of
 120 these. :)&lt;/p&gt;
 121
 122 &lt;p&gt;Via &lt;a href=&quot;http://www.debian.org/News/weekly/2013/18/&quot;&gt;Debian
 123 Project News for 2013-10-14&lt;/a&gt; I came across the Outreach Program for
 124 Women program which is a Google Summer of Code like initiative to get
 125 more women involved in free software.  One debian sponsor has offered
 126 to match &lt;a href=&quot;http://debian.ch/opw2013&quot;&gt;any donation done to Debian
 127 earmarked&lt;/a&gt; for this initiative.  I donated a few minutes ago, and
 128 hope you will to. :)&lt;/p&gt;
 129
 130 &lt;p&gt;And the Electronic Frontier Foundation just announced plans to
 131 create &lt;a href=&quot;https://supporters.eff.org/donate/nsa-videos&quot;&gt;video
 132 documentaries about the excessive spying&lt;/a&gt; on every Internet user that
 133 take place these days, and their need to fund the work.  I&#39;ve already
 134 donated.  Are you next?&lt;/p&gt;
 135
 136 &lt;p&gt;For my Norwegian audience, the organisation Studentenes og
 137 Akademikernes Internasjonale Hjelpefond is collecting signatures for a
 138 statement under the heading
 139 &lt;a href=&quot;http://saih.no/Bloggers_United/&quot;&gt;Bloggers United for Open
 140 Access&lt;/a&gt; for those of us asking for more focus on open access in the
 141 Norwegian government.  So far 499 signatures.  I hope you will sign it
 142 too.&lt;/p&gt;
 143 </description>
 144         </item>
 145
 146         <item>
 147                 <title>Oslo community mesh network - with NUUG and Hackeriet at Hausmania</title>
 148                 <link>http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</link>
 149                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Oslo_community_mesh_network___with_NUUG_and_Hackeriet_at_Hausmania.html</guid>
 150                 <pubDate>Fri, 11 Oct 2013 14:10:00 +0200</pubDate>
 151                 <description>&lt;p&gt;Wireless mesh networks are self organising and self healing
 152 networks that can be used to connect computers across small and large
 153 areas, depending on the radio technology used.  Normal wifi equipment
 154 can be used to create home made radio networks, and there are several
 155 successful examples like
 156 &lt;a href=&quot;http://www.freifunk.net/&quot;&gt;Freifunk&lt;/a&gt; and
 157 &lt;a href=&quot;http://www.awmn.net/&quot;&gt;Athens Wireless Metropolitan Network&lt;/a&gt;
 158 (see
 159 &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_wireless_community_networks_by_region#Greece&quot;&gt;wikipedia
 160 for a large list&lt;/a&gt;) around the globe.  To give you an idea how it
 161 work, check out the nice overview of the Kiel Freifunk community which
 162 can be seen from their
 163 &lt;a href=&quot;http://freifunk.in-kiel.de/ffmap/nodes.html&quot;&gt;dynamically
 164 updated node graph and map&lt;/a&gt;, where one can see how the mesh nodes
 165 automatically handle routing and recover from nodes disappearing.
 166 There is also a small community mesh network group in Oslo, Norway,
 167 and that is the main topic of this blog post.&lt;/p&gt;
 168
 169 &lt;p&gt;I&#39;ve wanted to check out mesh networks for a while now, and hoped
 170 to do it as part of my involvement with the &lt;a
 171 href=&quot;http://www.nuug.no/&quot;&gt;NUUG member organisation&lt;/a&gt; community, and
 172 my recent involvement in
 173 &lt;a href=&quot;https://wiki.debian.org/FreedomBox&quot;&gt;the Freedombox project&lt;/a&gt;
 174 finally lead me to give mesh networks some priority, as I suspect a
 175 Freedombox should use mesh networks to connect neighbours and family
 176 when possible, given that most communication between people are
 177 between those nearby (as shown for example by research on Facebook
 178 communication patterns).  It also allow people to communicate without
 179 any central hub to tap into for those that want to listen in on the
 180 private communication of citizens, which have become more and more
 181 important over the years.&lt;/p&gt;
 182
 183 &lt;p&gt;So far I have only been able to find one group of people in Oslo
 184 working on community mesh networks, over at the hack space
 185 &lt;a href=&quot;http://hackeriet.no/&quot;&gt;Hackeriet&lt;/a&gt; at Husmania.  They seem to
 186 have started with some Freifunk based effort using OLSR, called
 187 &lt;a href=&quot;http://oslo.freifunk.net/index.php?title=Main_Page&quot;&gt;the Oslo
 188 Freifunk project&lt;/a&gt;, but that effort is now dead and the people
 189 behind it have moved on to a batman-adv based system called
 190 &lt;a href=&quot;http://meshfx.org/trac&quot;&gt;meshfx&lt;/a&gt;.  Unfortunately the wiki
 191 site for the Oslo Freifunk project is no longer possible to update to
 192 reflect this fact, so the old project page can&#39;t be updated to point to
 193 the new project.  A while back, the people at Hackeriet invited people
 194 from the Freifunk community to Oslo to talk about mesh networks.  I
 195 came across this video where Hans Jørgen Lysglimt interview the
 196 speakers about this talk (from
 197 &lt;a href=&quot;https://www.youtube.com/watch?v=N2Kd7CLkhSY&quot;&gt;youtube&lt;/a&gt;):&lt;/p&gt;
 198
 199 &lt;p&gt;&lt;iframe width=&quot;420&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/N2Kd7CLkhSY&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;&lt;/p&gt;
 200
 201 &lt;p&gt;I mentioned OLSR and batman-adv, which are mesh routing protocols.
 202 There are heaps of different protocols, and I am still struggling to
 203 figure out which one would be &quot;best&quot; for some definitions of best, but
 204 given that the community mesh group in Oslo is so small, I believe it
 205 is best to hook up with the existing one instead of trying to create a
 206 completely different setup, and thus I have decided to focus on
 207 batman-adv for now.  It sure help me to  know that the very cool
 208 &lt;a href=&quot;http://www.servalproject.org/&quot;&gt;Serval project in Australia&lt;/a&gt;
 209 is using batman-adv as their meshing technology when it create a self
 210 organizing and self healing telephony system for disaster areas and
 211 less industrialized communities.  Check out this cool video presenting
 212 that project (from
 213 &lt;a href=&quot;https://www.youtube.com/watch?v=30qNfzJCQOA&quot;&gt;youtube&lt;/a&gt;):&lt;/p&gt;
 214
 215 &lt;p&gt;&lt;iframe width=&quot;560&quot; height=&quot;315&quot; src=&quot;https://www.youtube.com/embed/30qNfzJCQOA&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;&lt;/p&gt;
 216
 217 &lt;p&gt;According to the wikipedia page on
 218 &lt;a href=&quot;http://en.wikipedia.org/wiki/Wireless_mesh_network&quot;&gt;Wireless
 219 mesh network&lt;/a&gt; there are around 70 competing schemes for routing
 220 packets across mesh networks, and OLSR, B.A.T.M.A.N. and
 221 B.A.T.M.A.N. advanced are protocols used by several free software
 222 based community mesh networks.&lt;/p&gt;
 223
 224 &lt;p&gt;The batman-adv protocol is a bit special, as it provide layer 2
 225 (as in ethernet ) routing, allowing ipv4 and ipv6 to work on the same
 226 network.  One way to think about it is that it provide a mesh based
 227 vlan you can bridge to or handle like any other vlan connected to your
 228 computer.  The required drivers are already in the Linux kernel at
 229 least since Debian Wheezy, and it is fairly easy to set up.  A
 230 &lt;a href=&quot;http://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide&quot;&gt;good
 231 introduction&lt;/a&gt; is available from the Open Mesh project.  These are
 232 the key settings needed to join the Oslo meshfx network:&lt;/p&gt;
 233
 234 &lt;p&gt;&lt;table&gt;
 235 &lt;tr&gt;&lt;th&gt;Setting&lt;/th&gt;&lt;th&gt;Value&lt;/th&gt;&lt;/tr&gt;
 236 &lt;tr&gt;&lt;td&gt;Protocol / kernel module&lt;/td&gt;&lt;td&gt;batman-adv&lt;/td&gt;&lt;/tr&gt;
 237 &lt;tr&gt;&lt;td&gt;ESSID&lt;/td&gt;&lt;td&gt;meshfx@hackeriet&lt;/td&gt;&lt;/tr&gt;
 238 &lt;td&gt;Channel / Frequency&lt;/td&gt;&lt;td&gt;11 / 2462&lt;/td&gt;&lt;/tr&gt;
 239 &lt;td&gt;Cell ID&lt;/td&gt;&lt;td&gt;02:BA:00:00:00:01&lt;/td&gt;
 240 &lt;/table&gt;&lt;/p&gt;
 241
 242 &lt;p&gt;The reason for setting ad-hoc wifi Cell ID is to work around bugs
 243 in firmware used in wifi card and wifi drivers.  (See a nice post from
 244 VillageTelco about
 245 &quot;&lt;a href=&quot;http://tiebing.blogspot.no/2009/12/ad-hoc-cell-splitting-re-post-original.html&quot;&gt;Information
 246 about cell-id splitting, stuck beacons, and failed IBSS merges!&lt;/a&gt;
 247 for details.)  When these settings are activated and you have some
 248 other mesh node nearby, your computer will be connected to the mesh
 249 network and can communicate with any mesh node that is connected to
 250 any of the nodes in your network of nodes. :)&lt;/p&gt;
 251
 252 &lt;p&gt;My initial plan was to reuse my old Linksys WRT54GL as a mesh node,
 253 but that seem to be very hard, as I have not been able to locate a
 254 firmware supporting batman-adv.  If anyone know how to use that old
 255 wifi access point with batman-adv these days, please let me know.&lt;/p&gt;
 256
 257 &lt;p&gt;If you find this project interesting and want to join, please join
 258 us on IRC, either channel
 259 &lt;a href=&quot;irc://irc.freenode.net/#oslohackerspace&quot;&gt;#oslohackerspace&lt;/a&gt;
 260 or &lt;a href=&quot;irc://irc.freenode.net/#nuug&quot;&gt;#nuug&lt;/a&gt; on
 261 irc.freenode.net.&lt;/p&gt;
 262
 263 &lt;p&gt;While investigating mesh networks in Oslo, I came across an old
 264 research paper from the university of Stavanger and Telenor Research
 265 and Innovation called
 266 &lt;a href=&quot;http://folk.uio.no/paalee/publications/netrel-egeland-iswcs-2008.pdf&quot;&gt;The
 267 reliability of wireless backhaul mesh networks&lt;/a&gt; and elsewhere
 268 learned that Telenor have been experimenting with mesh networks at
 269 Grünerløkka in Oslo.  So mesh networks are also interesting for
 270 commercial companies, even though Telenor discovered that it was hard
 271 to figure out a good business plan for mesh networking and as far as I
 272 know have closed down the experiment.  Perhaps Telenor or others would
 273 be interested in a cooperation?&lt;/p&gt;
 274
 275 &lt;p&gt;&lt;strong&gt;Update 2013-10-12&lt;/strong&gt;: I was just
 276 &lt;a href=&quot;http://lists.alioth.debian.org/pipermail/freedombox-discuss/2013-October/005900.html&quot;&gt;told
 277 by the Serval project developers&lt;/a&gt; that they no longer use
 278 batman-adv (but are compatible with it), but their own crypto based
 279 mesh system.&lt;/p&gt;
 280 </description>
 281         </item>
 282
 283         <item>
 284                 <title>Skolelinux / Debian Edu 7.1 install and overview video from Marcelo Salvador</title>
 285                 <link>http://people.skolelinux.org/pere/blog/Skolelinux___Debian_Edu_7_1_install_and_overview_video_from_Marcelo_Salvador.html</link>
 286                 <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Skolelinux___Debian_Edu_7_1_install_and_overview_video_from_Marcelo_Salvador.html</guid>
 287                 <pubDate>Tue, 8 Oct 2013 17:10:00 +0200</pubDate>
 288                 <description>&lt;p&gt;The other day I was pleased and surprised to discover that Marcelo
 289 Salvador had published a
 290 &lt;a href=&quot;https://www.youtube.com/watch?v=w-GgpdqgLFc&quot;&gt;video on
 291 Youtube&lt;/a&gt; showing how to install the standalone Debian Edu /
 292 Skolelinux profile.  This is the profile intended for use at home or
 293 on laptops that should not be integrated into the provided network
 294 services (no central home directory, no Kerberos / LDAP directory etc,
 295 in other word a single user machine).  The result is 11 minutes long,
 296 and show some user applications (seem to be rather randomly picked).
 297 Missed a few of my favorites like celestia, planets and chromium
 298 showing the &lt;a href=&quot;http://www.zygotebody.com/&quot;&gt;Zygote Body 3D model
 299 of the human body&lt;/a&gt;, but I guess he did not know about those or find
 300 other programs more interesting. :) And the video do not show the
 301 advantages I believe is one of the most valuable featuers in Debian
 302 Edu, its central school server making it possible to run hundreds of
 303 computers without hard drives by installing one central
 304 &lt;a href=&quot;http://www.ltsp.org/&quot;&gt;LTSP server&lt;/a&gt;.&lt;/p&gt;
 305
 306 &lt;p&gt;Anyway, check out the video, embedded below and linked to above:&lt;/p&gt;
 307
 308 &lt;iframe width=&quot;420&quot; height=&quot;315&quot; src=&quot;http://www.youtube.com/embed/w-GgpdqgLFc&quot; frameborder=&quot;0&quot; allowfullscreen&gt;&lt;/iframe&gt;
 309
 310 &lt;p&gt;Are there other nice videos demonstrating Skolelinux?  Please let
 311 me know. :)&lt;/p&gt;
 312 </description>
 313         </item>
 314
 315         </channel>
 316 </rss>