Opened 2 weeks ago

Last modified 3 days ago

#30441 assigned defect

Stop BridgeDB from handing out offline bridges

Reported by: phw Owned by: phw
Priority: Very High Milestone:
Component: Circumvention/BridgeDB Version:
Severity: Major Keywords:
Cc: cohosh, phw, gk Actual Points:
Parent ID: Points: 2
Reviewer: Sponsor:


BridgeDB currently hands out plenty of bridges (in all flavours) that are offline. We need to understand why this is the case, and stop it from doing that.

For example, I just got the obfs4 bridge 4C480695650EDB6BAB006DB9FD81F6173122E973 over HTTPS. Nothing responds on its obfs4 port and Metrics says that it's currently offline -- or used to be, a few hours ago, to be precise. The bridge's IP address is part of Serge's most recent networkstatus-bridges file, but the bridge does not have the Running flag and should not have been given out. Also, the bridge's fingerprint isn't part of BridgeDB's latest assignments.log file. According to all of this, I should not have been given that bridge.

Child Tickets

Change History (6)

comment:1 Changed 2 weeks ago by phw

In d15fe16c and 978f9be8 we improved log messages to get a better understanding of what's going on. The latest run produced these log messages:

Trying to insert 1291 bridges into hashring, 1062 of which have the 'Running' flag...
Tried to insert 1280 bridges into hashring. Resulting hashring is of length 1061.

comment:2 Changed 2 weeks ago by phw

We discussed this on IRC and figured that the ~330 snap bridges may be the culprit to some extent. There's quite a bit of churn among them, so Serge may deem a snap bridge running at hour t and once a user tries to use it at hour t+1 it may already be offline.

comment:3 Changed 2 weeks ago by phw

Roger got a non-snap obfs4 bridge from BridgeDB that was also offline. Its vanilla port worked (and hence it had the 'Running' flag and was distributed by BridgeDB) but its obfs4 port would just reset connections. It may be that the problem of "BridgeDB hands out offline bridges" is really just a lot of smaller problems that come together.

comment:4 Changed 2 weeks ago by gk

Cc: gk added

comment:5 Changed 9 days ago by phw

Points: 2

comment:6 Changed 3 days ago by gk

What is the plan here? Any updates? That's still an often reported issue on our blog.

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