New SOCKS port restriction to only allow connections to .onion
While working on Ricochet to make it the a post-TCP/IP IM client, special and I have been considering ways to sandbox it further. We decided it would be nice to have a way to mark a given tor SOCKS (unix socket) listener as only allowing connections to .onion addresses.
This is similar to setting the option to not allow IPv4 - except we don't want DNS, IPv6 or any connection except to an onion service.