tor connection-handler should do SOCKS over arbitrary endpoint

[Brian Warner]

The tor connection handlers (in foolscap.connections.tor) are currently limited to speaking SOCKS over a TCP endpoint (specifically the arguments are hostname and port). It'd be nice if this could take an arbitrary endpoint, like a unix-domain socket.

I think it might be possible to call txtorcon.TorClientendpoint in a sneaky way to get around this (e.g. set _proxy_endpoint_generator= to something which returns the endpoint directly, instead of building a new TCP endpoint from socks_hostname/socks_port), but I'd bet that's depending on internal implementation details, or arguments that were meant for testing and not for applications to use.

[dawuud]

txtorcon progress happening here: ​https://github.com/meejah/txtorcon/pull/182

[dawuud]

here's my pull-request for the Foolscap tor handlers: ​https://github.com/warner/foolscap/pull/29

[dawuud]

successfully tested with a tor unix socket SOCKS port + my txtorcon patch + my tahoe tor handler patch ( ​https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2813 ). works fine.

[Brian Warner]

Landed in [1c2329fe0].