[ooni-dev] A first look at tor_bridge_reachability

[David Fifield]

Since https://github.com/TheTorProject/ooni-probe/issues/652 was merged,
there have been about five days of tcp_connect tests for Tor bridges and
directory authorities.

I've posted some preliminary code and analysis here:
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/
Interesting results so far:
 * Probes from 21 countries have contributed: BR, CZ, FI, GB, GR, ID,
   IN, IS, IT, KR, MM, MX, NL, NO, PK, TH, TR, TW, UG, US, VN.
 * The probes in ID and TH are reporting spurious reachability from
   destinations on port 80 (the destinations are down but the probes
   report connection success).
 * The probes in KR and MX are blocking some of the directory
   authorities.

Here is a big illustration, with one page per probe destination. Blue
dots are successful connection, gray dots are timeouts, and other colors
indicate other connection errors. The pages are sorted alphabetically by
nickname, so at the top you will see the bridge Azadi. Azadi has been
down for a few days, so its recent dots are gray.

https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf

These pages show spurious reachability from ID and TH to Azadi:80 (obfs4)
and fdctorbridge:80 (fte). These two bridges are both down: Azadi:80 is
having a temporary outage and fdctorbridge:80 was decommissioned a long
time ago. But two probe sites report them as reachable.

https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#2
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#23

The next listed pages show potential blocking of certain directory
authorities from KR and MX.
Blocked only in MX:
	dannenberg:80 (dir_port)
	dannenberg:443 (or_port)
	gabelmoo:80 (dir_port)
	gabelmoo:443 (or_port)
	maatuska:80 (dir_port)
	maatuska:443 (or_port)
Blocked in KR and MX:
	dizum:80 (dir_port)
	dizum:443 (or_port)
	moria1:9101 (dir_port)
	moria1:9131 (or_port)
	tor26:80 (dir_port)
	tor26:443 (or_port)
Additionally, moria1:9101 and moria1:9131 are blocked for the probe
identified as "ooni-ZZ-AS0".

https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#17
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#18
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#19
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#20
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#24
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#25
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#72
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#73
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#90
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#91
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#124
https://people.torproject.org/~dcf/graphs/ooni_tor_bridge_reachability/2016-12-14/ooni_tor_bridge_reachability_by_dest.pdf#125