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Published 20 hours ago • verified publisher icon torproject

Missing SENDME support on circuits

Open dgoulet-tor opened this issue 3 years ago • 1 comments

It appears that it is not possible to download a consensus over the ORPort of a relay due to Stem not sending SENDMEs (flow control cell) which means that after 500 cells on the stream (roughly 25k), the transfer will stop and a consensus or all descriptors are bigger than that.

Furthermore, Tor design complicates things because Stem would need to use SENDMEs on a stream and circuit as well which both have different windows.

On a stream, the starting window on a connection is 500 and on a circuit starting window is 1000. Then, tor-spec.txt specifies when/how to send a SENDME at the stream and circuit level.

dgoulet-tor avatar Apr 15 '21 12:04 dgoulet-tor

Interesting! Great catch David, I'd be delighted to merge a patch to address this.

atagar avatar Apr 15 '21 21:04 atagar