Hello all,

I am a PhD student, and am working on some measurements in Tor.

I am stuck at a point where i need to send multiple applications(streams) traffic through a single circuit.

I am currently using torsocks/torify to send traffic of these multiple applications through Tor.

The main problem is that, despite trying many different ways to achieve the same (sending multiple streams through a single circuit), i am not successful.

Things i have tried :

1.) Force Tor process to create only a single circuit at a time preventing any new circuit creation, so that any new stream would be attached to this only available circuit. To acheive this i have set the following Tor options :

set __DisablePredictedCircuits to 1
set MaxClientCircuitsPending to 1
set newcircuitperiod to 999999999
set maxcircuitdirtiness to 999999999

The problem with the above method is that it seems to work sometimes randomly. But most of the times for some reason, a new circuit is still created.

2.) Next, i assumed that maybe running torify multiple times for each application is the culprit, as it may try to create new circuit for each run. So i created a new bidirectional stream using socat, which listens on a local TCP port, and forwards the data to the Tor SOCKS port assuming that it will lead to a singe connection to local SOCKS.

Even this did not work and still new circuits were created randomly. 

3.) Next i tried to attach streams to circuits manually, using the stem library following the link : https://stem.torproject.org/tutorials/to_russia_with_love.html#custom-path-selection . This seemed to work initially, but then after every 4-5 runs, the streams seemed to detach automatically. Moreover, the original circuit crashed too.

It would be great, if someone could tell a simple way to achieve the same, or would point me to any mistakes that can be improved in the above methodologies to make them work.