RFC: Auto assign IPv6 prefixes and IPv4 mesh prefixes

[Noki]

I suggest the following changes to make the IP configuration more automated and therefore easier and to reduce the size of configuration files:

IPv6 subnets:

• If an ipv6_subprefix is manually set, assign that subnet to the vid
• If no ipv6_subprefix automatically assign subnets based on this rules
  • If vid is 40 assign 0 as ipv6_subprefix
  • If vid is 42 assign 1 as ipv6_subprefix
  • Else if vid >= 254 throw an error that auto assignment is not possible, otherwise assign -[vid] as ipv6_subprefix

IPv4 mesh IPs:

• Specify an ipv4_mesh_subnet as IP pool
• If an ipv4 prefix is manually set, assign that subnet to the vid / tunnel network
• If no ipv4 prefix is set automatically assign prefixes based on this rules
  • If the network has the role "mesh" or "tunnel" auto assign the next free /32 subnet from the ipv4_mesh_subnet IP pool

[FFHener]

I like this proposal as having them individually defined doesn't bring any benefit from my point of view. Just one quick note, in your sketch up i miss an error handling if i define vlan 1 and 42 as both would get the same ipv6_subprefix