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✏️ Editing: net_util.py

# Copyright (C) 2012 Canonical Ltd.
# Copyright (C) 2012, 2013 Hewlett-Packard Development Company, L.P.
# Copyright (C) 2012 Yahoo! Inc.
#
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

# This is a util function to translate debian based distro interface blobs as
# given in /etc/network/interfaces to an *somewhat* agnostic format for
# distributions that use other formats.
#
# TODO(harlowja) remove when we have python-netcf active...
#
# The format is the following:
# {
#    <device-name>: {
#        # All optional (if not existent in original format)
#        "netmask": <ip>,
#        "broadcast": <ip>,
#        "gateway": <ip>,
#        "address": <ip>,
#        "bootproto": "static"|"dhcp",
#        "dns-search": <hostname>,
#        "hwaddress": <mac-address>,
#        "auto": True (or non-existent),
#        "dns-nameservers": [<ip/hostname>, ...],
#    }
# }
#
# Things to note, comments are removed, if a ubuntu/debian interface is
# marked as auto then only then first segment (?) is retained, ie
# 'auto eth0 eth0:1' just marks eth0 as auto (not eth0:1).
#
# Example input:
#
# auto lo
# iface lo inet loopback
#
# auto eth0
# iface eth0 inet static
#         address 10.0.0.1
#         netmask 255.255.252.0
#         broadcast 10.0.0.255
#         gateway 10.0.0.2
#         dns-nameservers 98.0.0.1 98.0.0.2
#
# Example output:
# {
#     "lo": {
#         "auto": true
#     },
#     "eth0": {
#         "auto": true,
#         "dns-nameservers": [
#             "98.0.0.1",
#             "98.0.0.2"
#         ],
#         "broadcast": "10.0.0.255",
#         "netmask": "255.255.252.0",
#         "bootproto": "static",
#         "address": "10.0.0.1",
#         "gateway": "10.0.0.2"
#     }
# }

from cloudinit.net import mask_and_ipv4_to_bcast_addr, net_prefix_to_ipv4_mask

def translate_network(settings):
    # Get the standard cmd, args from the ubuntu format
    entries = []
    for line in settings.splitlines():
        line = line.strip()
        if not line or line.startswith("#"):
            continue
        split_up = line.split(None, 1)
        if len(split_up) <= 1:
            continue
        entries.append(split_up)
    # Figure out where each iface section is
    ifaces = []
    consume = {}
    for (cmd, args) in entries:
        if cmd == "iface":
            if consume:
                ifaces.append(consume)
                consume = {}
            consume[cmd] = args
        else:
            consume[cmd] = args
    # Check if anything left over to consume
    absorb = False
    for (cmd, args) in consume.items():
        if cmd == "iface":
            absorb = True
    if absorb:
        ifaces.append(consume)
    # Now translate
    real_ifaces = {}
    for info in ifaces:
        if "iface" not in info:
            continue
        iface_details = info["iface"].split(None)
        # Check if current device *may* have an ipv6 IP
        use_ipv6 = False
        if "inet6" in iface_details:
            use_ipv6 = True
        dev_name = None
        if len(iface_details) >= 1:
            dev = iface_details[0].strip().lower()
            if dev:
                dev_name = dev
        if not dev_name:
            continue
        iface_info = {}
        iface_info["ipv6"] = {}
        if len(iface_details) >= 3:
            proto_type = iface_details[2].strip().lower()
            # Seems like this can be 'loopback' which we don't
            # really care about
            if proto_type in ["dhcp", "static"]:
                iface_info["bootproto"] = proto_type
        # These can just be copied over
        if use_ipv6:
            for k in ["address", "gateway"]:
                if k in info:
                    val = info[k].strip().lower()
                    if val:
                        iface_info["ipv6"][k] = val
        else:
            for k in ["netmask", "address", "gateway", "broadcast"]:
                if k in info:
                    val = info[k].strip().lower()
                    if val:
                        iface_info[k] = val
            # handle static ip configurations using
            # ipaddress/prefix-length format
            if "address" in iface_info:
                if "netmask" not in iface_info:
                    # check if the address has a network prefix
                    addr, _, prefix = iface_info["address"].partition("/")
                    if prefix:
                        iface_info["netmask"] = net_prefix_to_ipv4_mask(prefix)
                        iface_info["address"] = addr
                        # if we set the netmask, we also can set the broadcast
                        iface_info["broadcast"] = mask_and_ipv4_to_bcast_addr(
                            iface_info["netmask"], addr
                        )

# Name server info provided??
            if "dns-nameservers" in info:
                iface_info["dns-nameservers"] = info["dns-nameservers"].split()
            # Name server search info provided??
            if "dns-search" in info:
                iface_info["dns-search"] = info["dns-search"].split()
            # Is any mac address spoofing going on??
            if "hwaddress" in info:
                hw_info = info["hwaddress"].lower().strip()
                hw_split = hw_info.split(None, 1)
                if len(hw_split) == 2 and hw_split[0].startswith("ether"):
                    hw_addr = hw_split[1]
                    if hw_addr:
                        iface_info["hwaddress"] = hw_addr
        # If ipv6 is enabled, device will have multiple IPs, so we need to
        # update the dictionary instead of overwriting it...
        if dev_name in real_ifaces:
            real_ifaces[dev_name].update(iface_info)
        else:
            real_ifaces[dev_name] = iface_info
    # Check for those that should be started on boot via 'auto'
    for (cmd, args) in entries:
        args = args.split(None)
        if not args:
            continue
        dev_name = args[0].strip().lower()
        if cmd == "auto":
            # Seems like auto can be like 'auto eth0 eth0:1' so just get the
            # first part out as the device name
            if dev_name in real_ifaces:
                real_ifaces[dev_name]["auto"] = True
        if cmd == "iface" and "inet6" in args:
            real_ifaces[dev_name]["inet6"] = True
    return real_ifaces

MR SKB