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Weekly Report -- 24/04/2014




Spent much of my week keeping an eye on BTM and dealing with new connections as they come online. Had a couple of false starts with the Wellington machine, as the management interface was up but was not allowing any inbound connections. This was finally sorted on Thursday night (turning the modem on and off again did the trick), so much of Friday was figuring out which Wellington connections were working and which were not.

A few of the BTM connections have a lot of difficulty running AMP tests to a few of the scheduled targets: AMP fails to resolve DNS properly for these targets but using dig or ping gets the right results. Did some packet captures to see what was going on: it looks like the answer record appears in the wrong section of the response and I guess libunbound doesn't deal with that too well. The problem seems to affect only connections using a specific brand of modem, so I am imagining there is some bug in the DNS cache software on the modem.

Continued tracing my NNTSC live export problem. It soon became apparent that NNTSC itself was not the problem: instead, the client was not reading data from NNTSC, causing the receive window to fill up and preventing NNTSC from sending new data. A bit of profiling suggested that the HMM detector in netevmon was potentially the problem. After disabling that detector, I was able to keep things running over the long weekend without any problems.

Fixed a libwandio bug in the LZO writer. Turns out that the "compression" can sometimes result in a larger block than the original uncompressed data, especially when doing full payload capture. In that case, you are supposed to write out the original block instead but we were mistakenly writing the compressed block.