On the 5th December 2018 we kicked off a two-day hackathon with participants from MAMI and the Open Observatory of Network Interference at the University of Aberdeen. The goal of the hackathon was to share experiences in Internet measurement between our projects.
We started with presentations from the participants to get everyone up to speed on what each other had been working on. Iain Learmonth presented PATHspider, Simone Basso presented ooniprobe and Raffaele Zullo presented tracemore.
While the MAMI measurements have had an Internet engineering focus attempting to find broken behavior in the Internet, OONI measurements focus on finding censorship in the Internet. Typically both broken behavior and censorship can be found implemented in middleboxes and so there is overlap between these areas of interest.
In Tracking transport-layer evolution with PATHspider, we identified with PATHspider that protocol-dependent connectivity failures can be correlated with networks that have large-scale censorship infrastructure. This is probably not deliberate, but a side effect of misconfiguration or poorly written software running on these boxes. To allow for OONI to leverage this discovery, three of the PATHspider tests for discovering broken middleboxes have been added to the OONI test specifications repository.
The tests we have added are for protocol-dependent connectivity failure of: ECN, TCP Fast Open and H2. Support for executing these tests in measurement-kit, the measurement library developed for use in ooniprobe, has already been added for TCP Fast Open and H2.
Ana Custura added support for using arbitrary socket options for DNS-based plugins in PATHspider that will enable new measurements that previously could only be performed with TCP.
One issue with PATHspider is that many of the tests require privileged access to the device, while OONI would like to have volunteers run measurements from their Android devices without requiring “rooting” or other techniques. We explored whether the ability to add eBPF programs to sockets used for measurements might be a substitute for privileged access and our initial thought experiments looked promising, however we did not have time to implement any experiments.
The MAMI project would like to thank Tor Project for partially supporting the costs for this event.