Allow managing IPv6 network settings

[bltavares]

ZeroTier has a couple of settings related to IPv6 address assignment
options which distribute IPv6 addresses computed based on the network id
and the node id.

RFC4139 assigns an single IPv6 address for each of the nodes.

6PLANE assigns a whole /80 prefix for each node, which could be
redistributed by the member, such as a router or used for Docker
containers.

Both of them are deterministic values calculated based on the network id
and node id, and they are not returned on the response of the
controller, given that the client is capable of calculating it itself.

IPv6 Assignment distribute IPv6 from the the assignment pool for each
member. If there is no IPv6 assignment pool configured, no route will be
distributed. It is important to also include the route configuration for
that network, so there is traffic through ZeroTier.

This commit exposes this information on the member resource, as a
computed property, so we could reference this information on other
Terraform resources (such as DNS settings or provisioner scripts).

Given this is a calculated property that is always present, downstream
modules should check if the network has it configured before using it.
No errors will be thrown, it would only not route properly if the
network has not enabled it.

The commit also exposes the settings in the network to enable each of
the IPv6 address distribution toggles on the network resource.

There is also a bug fix, where the IPv4 configuration toggle was
hardcoded and not reading the value from the resource definition.

[cormacrelf]

The auto_assign_6plane doesn't seem to do anything. Is that a ZT controller bug? The web UI sends this, whereas the code here only sends 6plane: true I think:

[bltavares]

While developing I've noticed that the UI is modifying the 6PLANE: true object, which seems to be an UI bug.

I've looked at the current controller code, and how my network behaves, and it seems that 6plane is the correct value to modify.

Using 6plane does not check the checkbox on ZeroTier, but it does display an extra IPv6 entry on each of the members. Ticking or unticking the checkbox does not change the members here. Does that happen on your network as well?

[cormacrelf]

ACK, same. Maybe file on zt.

[bltavares]

Given that the UI is not Open Source, I'll fill in a ticket with them

[bltavares]

Reported it on the chat channel. They'll take a look at it.

[bltavares]

@cormacrelf sorry to bother. Did you have time to check this change (and the others)? It would be nice to have a new release of the provider with the new additional features easy to download.

[cormacrelf]

@bltavares Sorry, I've been pretty busy. I had a few typos to fix on this one, but maybe for the rest I should just add you as a collaborator. How does that sound?

[bltavares]

One thing I've noticed when using this is that Terraform does not like to use directly references to this property as it begins with a number, but I also don't have a better name to propose.

So the following syntax does not compile:

variable "example" {
  default = "${zerotier_member.member.6plane_address}"
}

Instead, you need to use the dictionary access:

variable "example" {
  default = "${zerotier_member.member["6plane_address"]}"
}

Would you think of an alternative name for this?

[bltavares]

@cormacrelf I didn't mean to push this work over your schedule, sorry about that.

I've published a local build on my fork, so I could use it across machines, and I was meaning just to check if there was a delay due to the ZT UI bug, or the code itself.

I would gladly help with the future changes if that is something that would help you. I would like feedbacks on the change as well, anyway. I'm ok waiting for a slot on your schedule to have that feedback, as long as you need :)