Clean up TUN subsystem

[waddlesplash]

The new TUN subsystem has a number of things that should be fixed.

1. TAP-related code.

Does this actually work? (It doesn't look like it.) FreeBSD does have a unified TUN/TAP driver in their kernel, but there's a lot of TAP-related branching that we do not have. It may make more sense to remove a lot of this (as it doesn't appear to be correct anyway) until/when we actually implement TAP support.

2. Separate driver interface.

There's a lot of places where the network device module reads/writes into the driver interface or otherwise interacts with it across a FD boundary. This should be done away with, and the published device in devfs managed directly from the network device module. This should simplify a lot of code.

3. Proper path placement.

Reading FreeBSD's manual page, TUN interfaces behave like any other network interface (can be used with ifconfig, etc.) We thus shouldn't have /dev/tun0, but rather /dev/net/tun/0 etc. (As TUN interfaces are created on-demand, there won't be a /dev/net/tun directory at all unless one is created.)

[waddlesplash]

Reassigning to myself. I guess I will take a look at these things next week.

[kallisti5]

Attaching an openvpn patch to help. This refactor the one in haikuports to be "more sane" (and follow this new naming)

• fixing the odd static tap to a dynamic tun
• making the dynamic_name equal to the full path (later in the code it mentions dynamic_name is used simply for ifconfig calls.. our ifconfig uses full device paths)

Feel free to use, or adjust

[kallisti5]

openvpn patches

[kallisti5]

haiku patches i was playing with, likely less useful

[kallisti5]

stuff unhappy after these patches lol

[marcoapc]

This link can be used for references or implementation ideas: ​http://www.dest-unreach.org/socat/doc/socat-tun.html

​http://www.dest-unreach.org/socat/doc/socat.html#ADDRESS_TUN

​http://www.dest-unreach.org/socat/doc/socat.html#GROUP_TUN

[waddlesplash]

Overhaul done in hrev57427.