[tor-dev] carml: tasty treats from your Tor

[Roger Dingledine]

On Mon, Aug 04, 2014 at 10:03:04PM +0000, Leif Ryge wrote:
> Circuit 398 (tornodenl->Kaarli->CompSciR0x->FlappyBird) is EXTENDED for purpose "GENERAL"
> Circuit 398 (tornodenl->Kaarli->CompSciR0x->FlappyBird) is BUILT for purpose "GENERAL"
> Stream 2509 to 217.23.4.123.$EABB28C6030D78A98B0D8E3BF583463F49C04C59.exit:9001 attached via circuit 398
> 
> I've seen this happen several times: four hop circuits, followed by streams to
> the last hop using the .exit notation (that IP and fingerprint are for the
> relay FlappyBird, according to Atlas). I don't have AllowDotExit enabled in my
> torrc, fwiw.

Those sound like circuits for publishing or fetching hidden service
descriptors.

See write_stream_target_to_buf() which appends .exit to the stream
name when conn->chosen_exit_name is set.

And chosen_exit_name is populated in e.g. connection_ap_make_link()
when we glue a local directory fetch to a local stream to handle it.

> I'm also occassionally seeing single-hop circuits in the output of "circ -L",
> though I haven't noticed one being used yet.

Those are probably for fetching directory info over that relay's ORPort
using begin_dir.

--Roger