net: Depend on iproute2's ip instead of net-tools ifconfig or route

The net-tools package is deprecated and will eventually be dropped.  Use
"ip route", "link" or "address" instead of "ifconfig" or "route" calls.
Cloud-init can now run in an environment that no longer has net-tools.
This affects the network and route printing emitted to
cloud-config-output.log as well as the cc_disable_ec2_metadata module.

Additional changes:
 - separate readResource and resourceLocation into standalone test
   functions
 - Fix ipv4 address rows to report scopes represented by ip addr show
 - Formatted route/address ouput now handles multiple ipv4 and ipv6
   addresses on a single interface

Co-authored-by: James Hogarth <james.hogarth@gmail.com>
Co-authored-by: Robert Schweikert <rjschwei@suse.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/cloudinit/net/network_state.py b/cloudinit/net/network_state.py
index 6d63e5c5..72c803eb 100644
--- a/cloudinit/net/network_state.py
+++ b/cloudinit/net/network_state.py
@@ -7,6 +7,8 @@
 import copy
 import functools
 import logging
+import socket
+import struct
 
 import six
 
@@ -886,12 +888,9 @@ def net_prefix_to_ipv4_mask(prefix):
     This is the inverse of ipv4_mask_to_net_prefix.
         24 -> "255.255.255.0"
     Also supports input as a string."""
-
-    mask = [0, 0, 0, 0]
-    for i in list(range(0, int(prefix))):
-        idx = int(i / 8)
-        mask[idx] = mask[idx] + (1 << (7 - i % 8))
-    return ".".join([str(x) for x in mask])
+    mask = socket.inet_ntoa(
+        struct.pack(">I", (0xffffffff << (32 - int(prefix)) & 0xffffffff)))
+    return mask
 
 
 def ipv4_mask_to_net_prefix(mask):