Enable ipv6 connection & tunneling

[EkilDeew]

Enable ipv6 connection to Wireguard VPN servers & tunneling for IPv6 addresses.

There's still things to be done such as:

• use IPv6 by default and fallback to IPv4 if not functioning.
• check if IPv6 is enabled on host before attempting to contact an IPv6 server

Fixes #154
Might help #594

[qdm12]

Awesome, thanks!!

check if IPv6 is enabled on host before attempting to contact an IPv6 server

I think this is already done for example in the doIPv6 boolean in internal/wireguard.

use IPv6 by default and fallback to IPv4 if not functioning.

Call me a chicken, but I would rather have this as ipv4 first since most vpns don't support ipv6, let alone common systems/docker installs as well.

I'll do a gluetun release shortly since merging this will likely break some setups I would guess.

[EkilDeew]

Call me a chicken, but I would rather have this as ipv4 first since most vpns don't support ipv6, let alone common systems/docker installs as well.

You're completely right, i often forget how docker networks behaves 😅

[qdm12]

A few more comments, I'll test it out this weekend 👍

[qdm12]

Nice 👍

What provider do you use with IPv6 addresses by the way? Or is it the custom provider? Thanks!

[qdm12]

It's looking good. Note I rebased your branch on the master branch and added a few commits, so you might need to git reset --hard origin/ipv6 on your end before doing modifications again.

I will soon fix up GetConnection to only return IPv6 VPN server endpoints if IPv6 is supported, otherwise it will break a lot of setups only working with ipv4.

[qdm12]

This is the order of things I'm using for IPv6-ing everything:

• IPv6 support detection for Wireguard - already in place for some time now
• IPv6 support detection for OpenVPN - done in commit 5ddd703 for the latest image. It now uses the same IPv6 support detection as Wireguard (disabling the effect of OPENVPN_IPV6=on). I'm going to let it seat there for a few days to see if anyone complains about it on OpenVPN with IPv6-enabled systems. If you have an OpenVPN server to try it against, please have a go at it 😉 (I don't have ipv6 setup on my network / nor on docker).
• Pick IPv6 VPN endpoints ONLY if IPv6 is supported (will do it on master branch after point above is proven to work)
• Handling firewall, routing and rules for IPv6 (this PR) - will rebase this branch on master after the above is done

[qdm12]

@EkilDeew the whole series mentioned above is now complete, so merging this! Feel free to re-test the latest image to check it works as expected. You should also be able to connect to VPN servers over IPv6 (picked at random together with IPv4 though, unless you set the VPN_ENDPOINT_IP I think)