allow tor socks.port= to use unix-domain sockets

[warner]

Ideally the tahoe.cfg [tor] socks.port= value would be an arbitrary endpoint specification, and it would be possible to speak SOCKS over a unix-domain socket to the Tor daemon. But foolscap is currently limited to accepting TCP hostname+port, so we cannot accept the full range of endpoint specifiers yet.

This ticket tracks the changes necessary to lift this restriction. We need ​Foolscap#265 to be fixed first, which may require changes to txtorcon. Then we can change allmydata.node.Node._make_tor_handler to use endpoints.clientFromString(socksport).

[Brian Warner <warner@…>]

In a099b92/trunk:

tor: socks.port is now a (restricted) endpoint string

Foolscap has limitations that prevent us from accepting anything but a
TCP endpoint, but that will change in the future, so make the tahoe.cfg
syntax accept an endpoint, but then reject non-TCP ones. See the ticket
for details: refs ticket:2813.

This depends upon the new `foolscap.connections.tor.socks_port(host,
port)` API in foolscap-0.12.2, so it bumps the dependency to that (the
previous commit depended upon 0.12.1, but I hadn't gotten around to
updating the dep before now).

[dawuud]

i think we should simplify and remove some code; i've removed the parsing of the SOCKS port because it should be a twisted endpoint descriptor string and we can simply call clientFromString and then pass the resulting endpoint object to the Foolscap Tor SOCKS handler constructor:

​https://github.com/tahoe-lafs/tahoe-lafs/pull/327

please review

[David Stainton <dstainton415@…>]

In 1307c72/trunk:

Use the new Foolscap Tor handler, pass an endpoint for SOCKS connectivity

closes ticket:2813