Computerkram

I wrote a small Python script to visualize Tor relays on Google Maps and Google Earth. You can see the result here:

• Open in Google Maps (bad performance, less options)
• Download tormap.kml and open in Google Earth

The markers might give a false impression of accuracy. Most IPs can only be tracked to city level (or even region), ie. the markers are somewhat near, not necessarily at the real location of the relay. Continue reading "Visualization: Tor nodes on Google Maps and Google Earth"

Torouter is the codename for a hardware project using OpenWRT; it promises to provide a platform to provide an easy to setup Tor bridge as well as free Wireless transparently routed through Tor. Continue reading "Torouter - Tor on OpenWRT"

In den letzten Jahren entstanden zahlreiche Initiativen für den Aufbau freier drahtloser Bürgernetze. Diese sogenannten Freenetworks benutzen Funknetz-Technologie, um eigene, unabhängige Netzinfrastrukturen aufzubauen. Aus den Prinzipien und Methoden, die dabei angewendet werden, lässt sich das Leitbild einer Netzwerk-Allmende ableiten. Continue reading "Die Konstruktion der Netzwerk-Allmende"

We run a high bandwidth Tor exit node on a Gbit connection. Unfortunately, the NIC by our hoster doesn't support MSI-X to distribute interrupt load across all cores. The latest linux kernel 2.6.35 adds a mechanism called Receive Packet Steering:


What took us a lot of time to figure out: /proc/interrupts still shows only CPU0 is used for NIC interrupt handling, even with RPS enabled. If you want to find out whether RPS is working, you have to look at /proc/softirqs instead (eg. with watch -n1 cat /proc/softirqs):

                CPU0       CPU1       CPU2       CPU3
      HI:          0          0          0          0
   TIMER:  480622794  476948579  460999919  467641124
  NET_TX:   25311134   27075847   27513332   27307975     <-----
  NET_RX: 1388399338 4191697027 1491556667  627387845     <-----
   BLOCK:    4632803          3     315726         29
BLOCK_IOPOLL:          0          0          0          0
 TASKLET:         21          4          8          2
   SCHED:  154913375  158601463   97907175  200790209
 HRTIMER:    1576760    2361409    1330088    1545921
     RCU:  421549961  407634645  405460584  415147363

In our case, we had to specifically enable RPS:

# cat /sys/class/net/eth0/queues/rx-0/rps_cpus
00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,
00000000,00000000,00000000,00000000,00000000,00000000,00000000

# echo f > /sys/class/net/eth0/queues/rx-0/rps_cpus
# cat /sys/class/net/eth0/queues/rx-0/rps_cpus
00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,
00000000,00000000,00000000,00000000,00000000,00000000,0000000f

I have added the echo line to /etc/interfaces to set it on each boot ("up ...").

More Information

• lwn.net: rps: Receive packet steering
• Google Group Redis-DB: better multi-core functionality via per-process shared memory queues

Seit einem Monat betreibe ich torservers.net, und jetzt ist an der Zeit einen Blick zurück zu werfen. Continue reading "Torservers.net: Warum es so wichtig ist."

I put together some quick&dirty PHP scripts to extract my Twitter feed and resolve short URLs: http://ticker.wiredwings.com/
If you're interested in the sources, let me know.

Update: I have pushed the sources to github now: https://github.com/moba/twitterarchive. No cleaning, no documentation, plain ugly.

Note to self: Don't forget to set configuration option PidFile in torrc when you run multiple instances of Tor.

BigQuery and Prediction API: Get more from your data with Google (via momb, 19.05.2010)

The Prediction API enables access to Google's machine learning algorithms to analyze your historic data and predict likely future outcomes. Upload your data to Google Storage for Developers, then use the Prediction API to make real-time decisions in your applications. The Prediction API implements supervised learning algorithms as a RESTful web service to let you leverage patterns in your data, providing more relevant information to your users.

Adobe Flash To Eliminate Bandwidth Costs With P2P (TorrentFreak, 19.05.2010)

Kevin Towes, Product Manager of Adobe Flash Media Server told Beet.TV that the upcoming release of the Flash player will include new P2P technology that will “significantly change the way we think of media delivery.” According to Towes, this technology could in some cases completely eliminate bandwidth costs.

UKash, one of the few prepaid voucher companies in Europe ("privacy aware payment"), is now also the first legal vendor of virtual credit cards in Europe: Apparently you can buy prepaid vouchers and turn them into a 3-month virtual Mastercard (no physical card is issued, card number is delivered by email, CVV2 by SMS). http://www.ukashneo.com/

A friend of mine asked me for DVD case insert templates. Because the net is full of crap, I've bookmarked some good sources:

- http://www.oasiscd.com/graphics/templates-dvd.asp (Photoshop, Illustrator, InDesign, FreeHand, QuarkXPress, CorelDRAW)
- http://www.snjcd.com/templates.html (dito)
- http://www.effectuality.com/digital_templates.shtml (also has Word templates)

• Matthias Schwenk: Ausweitung der Kampfzone: Google investiert in das Startup “Recorded Future” (Carta, 05.05.2010)
  Defined tags for this entry: carta, internet, privacy

Take a moment and guess how large the database of all Wikipedia articles is, in all languages, in all countries together. Continue reading "The Size of Information: How much space does Wikipedia need?"

• John M. Schanck: Snakes on a Tor (SoaT) exit scanner
• Kevin Berry: Extending Tor Network Metrics
• Harry Bock: Rewriting the Tor DNS exit list TorDNSEL

Good luck, and happy coding!