New feature: forward ports

[lbdroid]

Create UI for enable unlimited number of unique port forwards to remote servers. Option to start port forwards automatically on boot (necessarily requires some form of ping test to maintain connection).

Example of utility: access to remote print server without having to expose cups to the internet.

[lbdroid]

Scheme;

New menu drawer item: "Forwards" --> new Fragment.
This new fragment contains a vertical list of pre-defined port forwards (buttons) by name, scrollable. In addition, a fixed-to-screen circle-"plus" button to add a new forward. Also green/red dot on button to indicate running state of that forward.

When click on a forward (including new forward), open a new (fragment? popup?) with details for that forward.

Name,
Parameters (i.e. "-l username -L port:host:hostport host cat -"),
selectable-but-not-editable public key,
button to input new key pair (popup --> generate or input. Generate returns with new public key in field above, input opens another popup with empty text fields for private/public keys and set/cancel buttons),
autostart (at boot) checkbox,
run-as-root checkbox,
start/stop/restart buttons,
running-state of that forward.

[lbdroid]

Idea: service managing autossh instances. Monitor all processes that called for a tunnel's bringup, when last one has terminated, bring tunnel down. Special provision for manual bringup/down that introduces or terminates a stayup state flag.

[lbdroid]

Idea: acl for ssh tunnel functions. Not just permission request/grant, but scan system for packages requesting that permission and allow access to tunnels by individual whitelist.

[lbdroid]

In order to run autossh without user interaction, we are forced to skip host verification. I dont like this, so will add an optional server key to the tunnel config, enable host verification when the key is present, disable when not present.

[lbdroid]

This functionality is now in place.

Two remaining features to be implemented, server key for host verification, and tunnel acl.