Fix IPv6 netmask format for sysconfig (#1215)

This change converts the IPv6 netmask from the network_data.json[1]
format to the CIDR style, <IPv6_addr>/<prefix>.

Using an IPv6 address like ffff:ffff:ffff:ffff:: does not work with
NetworkManager, nor networkscripts.

NetworkManager will ignore the route, logging:
  ifcfg-rh: ignoring invalid route at \
    "::/:: via fd00:fd00:fd00:2::fffe dev $DEV" \
    (/etc/sysconfig/network-scripts/route6-$DEV:3): \
    Argument for "::/::" is not ADDR/PREFIX format

Similarly if using networkscripts, ip route fail with error:
  Error: inet6 prefix is expected rather than \
    "fd00:fd00:fd00::/ffff:ffff:ffff:ffff::".

Also a bit of refactoring ...

cloudinit.net.sysconfig.Route.to_string:
* Move a couple of lines around to reduce repeated code.
* if "ADDRESS" not in key -> continute, so that the
  code block following it can be de-indented.
cloudinit.net.network_state:
* Refactors the ipv4_mask_to_net_prefix, ipv6_mask_to_net_prefix
  removes mask_to_net_prefix methods. Utilize ipaddress library to
  do some of the heavy lifting.

LP: #1959148

1 files changed, 2 insertions, 2 deletions

diff --git a/cloudinit/sources/helpers/vmware/imc/config_nic.py b/cloudinit/sources/helpers/vmware/imc/config_nic.py
index df621f20..6c135f48 100644
--- a/cloudinit/sources/helpers/vmware/imc/config_nic.py
+++ b/cloudinit/sources/helpers/vmware/imc/config_nic.py
@@ -10,7 +10,7 @@ import os
 import re
 
 from cloudinit import subp, util
-from cloudinit.net.network_state import mask_to_net_prefix
+from cloudinit.net.network_state import ipv4_mask_to_net_prefix
 
 logger = logging.getLogger(__name__)
 
@@ -182,7 +182,7 @@ class NicConfigurator(object):
         """
         route_list = []
 
-        cidr = mask_to_net_prefix(netmask)
+        cidr = ipv4_mask_to_net_prefix(netmask)
 
         for gateway in gateways:
             destination = "%s/%d" % (gen_subnet(gateway, netmask), cidr)