pppoe: dhcpv6-pd: T421: initial support

The following configuration will assign a /64 prefix out of a /56 delegation
to eth0. The IPv6 address assigned to eth0 will be <prefix>::ffff/64.
If you do not know the prefix size delegated to you, start with sla-len 0.

  pppoe pppoe0 {
      authentication {
          password vyos
          user vyos
      }
      description sadfas
      dhcpv6-options {
          delegate eth0 {
              interface-id 65535
              sla-id 0
              sla-len 8
          }
      }
      ipv6 {
          address {
              autoconf
          }
          enable
      }
      source-interface eth1
  }

  vyos@vyos:~$ show interfaces
  Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
  Interface        IP Address                        S/L  Description
  ---------        ----------                        ---  -----------
  eth0             2001:db8:8003:400::ffff/64        u/u

0 files changed, 0 insertions, 0 deletions