# This file is part of cloud-init. See LICENSE file for license information.

import copy
import glob
import io
import logging
import os
import re
from typing import Dict, Optional

from cloudinit import subp, util
from cloudinit.distros.parsers import networkmanager_conf, resolv_conf
from cloudinit.net import (
    IPV6_DYNAMIC_TYPES,
    is_ipv6_address,
    net_prefix_to_ipv4_mask,
    renderer,
    subnet_is_ipv6,
)
from cloudinit.net.network_state import NetworkState

LOG = logging.getLogger(__name__)
KNOWN_DISTROS = [
    "almalinux",
    "centos",
    "cloudlinux",
    "eurolinux",
    "fedora",
    "miraclelinux",
    "openeuler",
    "OpenCloudOS",
    "openmandriva",
    "rhel",
    "rocky",
    "suse",
    "TencentOS",
    "virtuozzo",
]


def _make_header(sep="#"):
    lines = [
        "Created by cloud-init automatically, do not edit.",
        "",
    ]
    for i in range(len(lines)):
        if lines[i]:
            lines[i] = sep + " " + lines[i]
        else:
            lines[i] = sep
    return "\n".join(lines)


def _is_default_route(route):
    default_nets = ("::", "0.0.0.0")
    return route["prefix"] == 0 and route["network"] in default_nets


def _quote_value(value):
    if re.search(r"\s", value):
        # This doesn't handle complex cases...
        if value.startswith('"') and value.endswith('"'):
            return value
        else:
            return '"%s"' % value
    else:
        return value


class ConfigMap:
    """Sysconfig like dictionary object."""

    # Why does redhat prefer yes/no to true/false??
    _bool_map = {
        True: "yes",
        False: "no",
    }

    def __init__(self):
        self._conf = {}

    def __setitem__(self, key, value):
        self._conf[key] = value

    def __getitem__(self, key):
        return self._conf[key]

    def get(self, key):
        return self._conf.get(key)

    def __contains__(self, key):
        return key in self._conf

    def drop(self, key):
        self._conf.pop(key, None)

    def __len__(self):
        return len(self._conf)

    def skip_key_value(self, key, val):
        """Skip the pair key, value if it matches a certain rule."""
        return False

    def to_string(self):
        buf = io.StringIO()
        buf.write(_make_header())
        if self._conf:
            buf.write("\n")
        for key in sorted(self._conf.keys()):
            value = self._conf[key]
            if self.skip_key_value(key, value):
                continue
            if isinstance(value, bool):
                value = self._bool_map[value]
            if not isinstance(value, str):
                value = str(value)
            buf.write("%s=%s\n" % (key, _quote_value(value)))
        return buf.getvalue()

    def update(self, updates):
        self._conf.update(updates)


class Route(ConfigMap):
    """Represents a route configuration."""

    def __init__(self, route_name, base_sysconf_dir, ipv4_tpl, ipv6_tpl):
        super(Route, self).__init__()
        self.last_idx = 1
        self.has_set_default_ipv4 = False
        self.has_set_default_ipv6 = False
        self._route_name = route_name
        self._base_sysconf_dir = base_sysconf_dir
        self.route_fn_tpl_ipv4 = ipv4_tpl
        self.route_fn_tpl_ipv6 = ipv6_tpl

    def copy(self):
        r = Route(
            self._route_name,
            self._base_sysconf_dir,
            self.route_fn_tpl_ipv4,
            self.route_fn_tpl_ipv6,
        )
        r._conf = self._conf.copy()
        r.last_idx = self.last_idx
        r.has_set_default_ipv4 = self.has_set_default_ipv4
        r.has_set_default_ipv6 = self.has_set_default_ipv6
        return r

    @property
    def path_ipv4(self):
        return self.route_fn_tpl_ipv4 % (
            {"base": self._base_sysconf_dir, "name": self._route_name}
        )

    @property
    def path_ipv6(self):
        return self.route_fn_tpl_ipv6 % (
            {"base": self._base_sysconf_dir, "name": self._route_name}
        )

    def is_ipv6_route(self, address):
        return ":" in address

    def to_string(self, proto="ipv4"):
        # only accept ipv4 and ipv6
        if proto not in ["ipv4", "ipv6"]:
            raise ValueError("Unknown protocol '%s'" % (str(proto)))
        buf = io.StringIO()
        buf.write(_make_header())
        if self._conf:
            buf.write("\n")
        # need to reindex IPv4 addresses
        # (because Route can contain a mix of IPv4 and IPv6)
        reindex = -1
        for key in sorted(self._conf.keys()):
            if "ADDRESS" not in key:
                continue

            index = key.replace("ADDRESS", "")
            address_value = str(self._conf[key])
            gateway_value = str(self._conf["GATEWAY" + index])

            # only accept combinations:
            # if proto ipv6 only display ipv6 routes
            # if proto ipv4 only display ipv4 routes
            # do not add ipv6 routes if proto is ipv4
            # do not add ipv4 routes if proto is ipv6
            # (this array will contain a mix of ipv4 and ipv6)
            if proto == "ipv4" and not self.is_ipv6_route(address_value):
                netmask_value = str(self._conf["NETMASK" + index])
                # increase IPv4 index
                reindex = reindex + 1
                buf.write(
                    "%s=%s\n"
                    % ("ADDRESS" + str(reindex), _quote_value(address_value))
                )
                buf.write(
                    "%s=%s\n"
                    % ("GATEWAY" + str(reindex), _quote_value(gateway_value))
                )
                buf.write(
                    "%s=%s\n"
                    % ("NETMASK" + str(reindex), _quote_value(netmask_value))
                )
                metric_key = "METRIC" + index
                if metric_key in self._conf:
                    metric_value = str(self._conf[metric_key])
                    buf.write(
                        "%s=%s\n"
                        % ("METRIC" + str(reindex), _quote_value(metric_value))
                    )
            elif proto == "ipv6" and self.is_ipv6_route(address_value):
                prefix_value = str(self._conf[f"PREFIX{index}"])
                metric_value = (
                    "metric " + str(self._conf["METRIC" + index])
                    if "METRIC" + index in self._conf
                    else ""
                )
                buf.write(
                    "%s/%s via %s %s dev %s\n"
                    % (
                        address_value,
                        prefix_value,
                        gateway_value,
                        metric_value,
                        self._route_name,
                    )
                )

        return buf.getvalue()


class NetInterface(ConfigMap):
    """Represents a sysconfig/networking-script (and its config + children)."""

    iface_types = {
        "ethernet": "Ethernet",
        "bond": "Bond",
        "bridge": "Bridge",
        "infiniband": "InfiniBand",
        "vlan": "Vlan",
    }

    def __init__(
        self, iface_name, base_sysconf_dir, templates, kind="ethernet"
    ):
        super(NetInterface, self).__init__()
        self.children = []
        self.templates = templates
        route_tpl = self.templates.get("route_templates")
        self.routes = Route(
            iface_name,
            base_sysconf_dir,
            ipv4_tpl=route_tpl.get("ipv4"),
            ipv6_tpl=route_tpl.get("ipv6"),
        )
        self.iface_fn_tpl = self.templates.get("iface_templates")
        self.kind = kind

        self._iface_name = iface_name
        self._conf["DEVICE"] = iface_name
        self._base_sysconf_dir = base_sysconf_dir

    @property
    def name(self):
        return self._iface_name

    @name.setter
    def name(self, iface_name):
        self._iface_name = iface_name
        self._conf["DEVICE"] = iface_name

    @property
    def kind(self):
        return self._kind

    @kind.setter
    def kind(self, kind):
        if kind not in self.iface_types:
            raise ValueError(kind)
        self._kind = kind
        self._conf["TYPE"] = self.iface_types[kind]

    @property
    def path(self):
        return self.iface_fn_tpl % (
            {"base": self._base_sysconf_dir, "name": self.name}
        )

    def copy(self, copy_children=False, copy_routes=False):
        c = NetInterface(
            self.name, self._base_sysconf_dir, self.templates, kind=self._kind
        )
        c._conf = self._conf.copy()
        if copy_children:
            c.children = list(self.children)
        if copy_routes:
            c.routes = self.routes.copy()
        return c

    def skip_key_value(self, key, val):
        if key == "TYPE" and val == "Vlan":
            return True
        return False


class Renderer(renderer.Renderer):
    """Renders network information in a /etc/sysconfig format."""

    # See: https://access.redhat.com/documentation/en-US/\
    #      Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/\
    #      s1-networkscripts-interfaces.html (or other docs for
    #                                         details about this)

    iface_defaults = {
        "rhel": {
            "ONBOOT": True,
            "USERCTL": False,
            "BOOTPROTO": "none",
            "AUTOCONNECT_PRIORITY": 120,
        },
        "suse": {"BOOTPROTO": "static", "STARTMODE": "auto"},
    }

    cfg_key_maps = {
        "rhel": {
            "accept-ra": "IPV6_FORCE_ACCEPT_RA",
            "bridge_stp": "STP",
            "bridge_ageing": "AGEING",
            "bridge_bridgeprio": "PRIO",
            "mac_address": "HWADDR",
            "mtu": "MTU",
        },
        "suse": {
            "bridge_stp": "BRIDGE_STP",
            "bridge_ageing": "BRIDGE_AGEINGTIME",
            "bridge_bridgeprio": "BRIDGE_PRIORITY",
            "mac_address": "LLADDR",
            "mtu": "MTU",
        },
    }

    # If these keys exist, then their values will be used to form
    # a BONDING_OPTS / BONDING_MODULE_OPTS grouping; otherwise no
    # grouping will be set.
    bond_tpl_opts = tuple(
        [
            ("bond_mode", "mode=%s"),
            ("bond_xmit_hash_policy", "xmit_hash_policy=%s"),
            ("bond_miimon", "miimon=%s"),
            ("bond_min_links", "min_links=%s"),
            ("bond_arp_interval", "arp_interval=%s"),
            ("bond_arp_ip_target", "arp_ip_target=%s"),
            ("bond_arp_validate", "arp_validate=%s"),
            ("bond_ad_select", "ad_select=%s"),
            ("bond_num_grat_arp", "num_grat_arp=%s"),
            ("bond_downdelay", "downdelay=%s"),
            ("bond_updelay", "updelay=%s"),
            ("bond_lacp_rate", "lacp_rate=%s"),
            ("bond_fail_over_mac", "fail_over_mac=%s"),
            ("bond_primary", "primary=%s"),
            ("bond_primary_reselect", "primary_reselect=%s"),
        ]
    )

    templates: dict = {}

    def __init__(self, config=None):
        if not config:
            config = {}
        self.sysconf_dir = config.get("sysconf_dir", "etc/sysconfig")
        self.netrules_path = config.get(
            "netrules_path", "etc/udev/rules.d/70-persistent-net.rules"
        )
        self.dns_path = config.get("dns_path", "etc/resolv.conf")
        nm_conf_path = "etc/NetworkManager/conf.d/99-cloud-init.conf"
        self.networkmanager_conf_path = config.get(
            "networkmanager_conf_path", nm_conf_path
        )
        self.templates = {
            "control": config.get("control"),
            "iface_templates": config.get("iface_templates"),
            "route_templates": config.get("route_templates"),
        }
        self.flavor = config.get("flavor", "rhel")

    @classmethod
    def _render_iface_shared(cls, iface, iface_cfg, flavor):
        flavor_defaults = copy.deepcopy(cls.iface_defaults.get(flavor, {}))
        iface_cfg.update(flavor_defaults)

        for old_key in ("mac_address", "mtu", "accept-ra"):
            old_value = iface.get(old_key)
            if old_value is not None:
                # only set HWADDR on physical interfaces
                if old_key == "mac_address" and iface["type"] not in [
                    "physical",
                    "infiniband",
                ]:
                    continue
                new_key = cls.cfg_key_maps[flavor].get(old_key)
                if new_key:
                    iface_cfg[new_key] = old_value

        # only set WakeOnLan for physical interfaces
        if (
            "wakeonlan" in iface
            and iface["wakeonlan"]
            and iface["type"] == "physical"
        ):
            iface_cfg["ETHTOOL_OPTS"] = "wol g"

    @classmethod
    def _render_subnets(cls, iface_cfg, subnets, has_default_route, flavor):
        # setting base values
        if flavor == "suse":
            iface_cfg["BOOTPROTO"] = "static"
            if "BRIDGE" in iface_cfg:
                iface_cfg["BOOTPROTO"] = "dhcp"
                iface_cfg.drop("BRIDGE")
        else:
            iface_cfg["BOOTPROTO"] = "none"

        # modifying base values according to subnets
        for i, subnet in enumerate(subnets, start=len(iface_cfg.children)):
            mtu_key = "MTU"
            subnet_type = subnet.get("type")
            if subnet_type == "dhcp6" or subnet_type == "ipv6_dhcpv6-stateful":
                if flavor == "suse":
                    # User wants dhcp for both protocols
                    if iface_cfg["BOOTPROTO"] in ("dhcp4", "dhcp"):
                        iface_cfg["BOOTPROTO"] = "dhcp"
                    else:
                        # Only IPv6 is DHCP, IPv4 may be static
                        iface_cfg["BOOTPROTO"] = "dhcp6"
                    iface_cfg["DHCLIENT6_MODE"] = "managed"
                # only if rhel AND dhcpv6 stateful
                elif flavor == "rhel" and (
                    subnet_type == "ipv6_dhcpv6-stateful"
                ):
                    iface_cfg["DHCPV6C"] = True
                    iface_cfg["IPV6INIT"] = True
                    iface_cfg["IPV6_AUTOCONF"] = False
                    iface_cfg["IPV6_FAILURE_FATAL"] = True
                else:
                    iface_cfg["IPV6INIT"] = True
                    # Configure network settings using DHCPv6
                    iface_cfg["DHCPV6C"] = True
            elif subnet_type == "ipv6_dhcpv6-stateless":
                if flavor == "suse":
                    # User wants dhcp for both protocols
                    if iface_cfg["BOOTPROTO"] in ("dhcp4", "dhcp"):
                        iface_cfg["BOOTPROTO"] = "dhcp"
                    else:
                        # Only IPv6 is DHCP, IPv4 may be static
                        iface_cfg["BOOTPROTO"] = "dhcp6"
                    iface_cfg["DHCLIENT6_MODE"] = "info"
                else:
                    iface_cfg["IPV6INIT"] = True
                    # Configure network settings using SLAAC from RAs and
                    # optional info from dhcp server using DHCPv6
                    iface_cfg["IPV6_AUTOCONF"] = True
                    iface_cfg["DHCPV6C"] = True
                    # Use Information-request to get only stateless
                    # configuration parameters (i.e., without address).
                    iface_cfg["DHCPV6C_OPTIONS"] = "-S"
            elif subnet_type == "ipv6_slaac":
                if flavor == "suse":
                    # User wants dhcp for both protocols
                    if iface_cfg["BOOTPROTO"] in ("dhcp4", "dhcp"):
                        iface_cfg["BOOTPROTO"] = "dhcp"
                    else:
                        # Only IPv6 is DHCP, IPv4 may be static
                        iface_cfg["BOOTPROTO"] = "dhcp6"
                    iface_cfg["DHCLIENT6_MODE"] = "info"
                else:
                    iface_cfg["IPV6INIT"] = True
                    # Configure network settings using SLAAC from RAs
                    iface_cfg["IPV6_AUTOCONF"] = True
            elif subnet_type in ["dhcp4", "dhcp"]:
                bootproto_in = iface_cfg["BOOTPROTO"]
                iface_cfg["BOOTPROTO"] = "dhcp"
                if flavor == "suse":
                    # If dhcp6 is already specified the user wants dhcp
                    # for both protocols
                    if bootproto_in not in ("dhcp6", "dhcp"):
                        # Only IPv4 is DHCP, IPv6 may be static
                        iface_cfg["BOOTPROTO"] = "dhcp4"
            elif subnet_type in ["static", "static6"]:
                # RH info
                # grep BOOTPROTO sysconfig.txt -A2 | head -3
                # BOOTPROTO=none|bootp|dhcp
                # 'bootp' or 'dhcp' cause a DHCP client
                # to run on the device. Any other
                # value causes any static configuration
                # in the file to be applied.
                if subnet_is_ipv6(subnet) and flavor != "suse":
                    mtu_key = "IPV6_MTU"
                    iface_cfg["IPV6INIT"] = True
                if "mtu" in subnet:
                    mtu_mismatch = bool(
                        mtu_key in iface_cfg
                        and subnet["mtu"] != iface_cfg[mtu_key]
                    )
                    if mtu_mismatch:
                        LOG.warning(
                            "Network config: ignoring %s device-level mtu:%s"
                            " because ipv4 subnet-level mtu:%s provided.",
                            iface_cfg.name,
                            iface_cfg[mtu_key],
                            subnet["mtu"],
                        )
                    if subnet_is_ipv6(subnet):
                        if flavor == "suse":
                            # TODO(rjschwei) write mtu setting to
                            # /etc/sysctl.d/
                            pass
                        else:
                            iface_cfg[mtu_key] = subnet["mtu"]
                    else:
                        iface_cfg[mtu_key] = subnet["mtu"]

                if subnet_is_ipv6(subnet) and flavor == "rhel":
                    iface_cfg["IPV6_FORCE_ACCEPT_RA"] = False
                    iface_cfg["IPV6_AUTOCONF"] = False
            elif subnet_type == "manual":
                if flavor == "suse":
                    LOG.debug('Unknown subnet type setting "%s"', subnet_type)
                else:
                    # If the subnet has an MTU setting, then ONBOOT=True
                    # to apply the setting
                    iface_cfg["ONBOOT"] = mtu_key in iface_cfg
            else:
                raise ValueError(
                    "Unknown subnet type '%s' found for interface '%s'"
                    % (subnet_type, iface_cfg.name)
                )
            if subnet.get("control") == "manual":
                if flavor == "suse":
                    iface_cfg["STARTMODE"] = "manual"
                else:
                    iface_cfg["ONBOOT"] = False

        # set IPv4 and IPv6 static addresses
        ipv4_index = -1
        ipv6_index = -1
        for i, subnet in enumerate(subnets, start=len(iface_cfg.children)):
            subnet_type = subnet.get("type")
            # metric may apply to both dhcp and static config
            if "metric" in subnet:
                if flavor == "rhel":
                    if subnet_is_ipv6(subnet):
                        iface_cfg["IPV6_ROUTE_METRIC"] = subnet["metric"]
                    else:
                        iface_cfg["IPV4_ROUTE_METRIC"] = subnet["metric"]
                elif flavor != "suse":
                    iface_cfg["METRIC"] = subnet["metric"]
            if subnet_type in ["dhcp", "dhcp4"]:
                # On SUSE distros 'DHCLIENT_SET_DEFAULT_ROUTE' is a global
                # setting in /etc/sysconfig/network/dhcp
                if flavor != "suse":
                    if has_default_route and iface_cfg["BOOTPROTO"] != "none":
                        iface_cfg["DHCLIENT_SET_DEFAULT_ROUTE"] = False
                continue
            elif subnet_type in IPV6_DYNAMIC_TYPES:
                continue
            elif subnet_type in ["static", "static6"]:
                if subnet_is_ipv6(subnet):
                    ipv6_index = ipv6_index + 1
                    ipv6_cidr = "%s/%s" % (subnet["address"], subnet["prefix"])
                    if ipv6_index == 0:
                        if flavor == "suse":
                            iface_cfg["IPADDR6"] = ipv6_cidr
                        else:
                            iface_cfg["IPV6ADDR"] = ipv6_cidr
                    elif ipv6_index == 1:
                        if flavor == "suse":
                            iface_cfg["IPADDR6_1"] = ipv6_cidr
                        else:
                            iface_cfg["IPV6ADDR_SECONDARIES"] = ipv6_cidr
                    else:
                        if flavor == "suse":
                            iface_cfg["IPADDR6_%d" % ipv6_index] = ipv6_cidr
                        else:
                            iface_cfg["IPV6ADDR_SECONDARIES"] += (
                                " " + ipv6_cidr
                            )
                else:
                    ipv4_index = ipv4_index + 1
                    suff = "" if ipv4_index == 0 else str(ipv4_index)
                    iface_cfg["IPADDR" + suff] = subnet["address"]
                    iface_cfg["NETMASK" + suff] = net_prefix_to_ipv4_mask(
                        subnet["prefix"]
                    )

                if "gateway" in subnet and flavor != "suse":
                    iface_cfg["DEFROUTE"] = True
                    if is_ipv6_address(subnet["gateway"]):
                        iface_cfg["IPV6_DEFAULTGW"] = subnet["gateway"]
                    else:
                        iface_cfg["GATEWAY"] = subnet["gateway"]

                if "dns_search" in subnet and flavor != "suse":
                    iface_cfg["DOMAIN"] = " ".join(subnet["dns_search"])

                if "dns_nameservers" in subnet and flavor != "suse":
                    if len(subnet["dns_nameservers"]) > 3:
                        # per resolv.conf(5) MAXNS sets this to 3.
                        LOG.debug(
                            "%s has %d entries in dns_nameservers. "
                            "Only 3 are used.",
                            iface_cfg.name,
                            len(subnet["dns_nameservers"]),
                        )
                    for i, k in enumerate(subnet["dns_nameservers"][:3], 1):
                        iface_cfg["DNS" + str(i)] = k

    @classmethod
    def _render_subnet_routes(cls, iface_cfg, route_cfg, subnets, flavor):
        # TODO(rjschwei): route configuration on SUSE distro happens via
        # ifroute-* files, see lp#1812117. SUSE currently carries a local
        # patch in their package.
        if flavor == "suse":
            return
        for _, subnet in enumerate(subnets, start=len(iface_cfg.children)):
            subnet_type = subnet.get("type")
            for route in subnet.get("routes", []):
                is_ipv6 = subnet.get("ipv6") or is_ipv6_address(
                    route["gateway"]
                )

                # Any dynamic configuration method, slaac, dhcpv6-stateful/
                # stateless should get router information from router RA's.
                if (
                    _is_default_route(route)
                    and subnet_type not in IPV6_DYNAMIC_TYPES
                ):
                    if (
                        subnet.get("ipv4") and route_cfg.has_set_default_ipv4
                    ) or (
                        subnet.get("ipv6") and route_cfg.has_set_default_ipv6
                    ):
                        raise ValueError(
                            "Duplicate declaration of default "
                            "route found for interface '%s'" % (iface_cfg.name)
                        )
                    # NOTE that instead of defining the route0 settings,
                    # the owning interface provides the default route.

                    # TODO(harlowja): add validation that no other iface has
                    # also provided the default route?
                    iface_cfg["DEFROUTE"] = True
                    if iface_cfg["BOOTPROTO"] in ("dhcp", "dhcp4"):
                        iface_cfg["DHCLIENT_SET_DEFAULT_ROUTE"] = True
                    if "gateway" in route:
                        if is_ipv6:
                            iface_cfg["IPV6_DEFAULTGW"] = route["gateway"]
                            route_cfg.has_set_default_ipv6 = True
                        else:
                            iface_cfg["GATEWAY"] = route["gateway"]
                            route_cfg.has_set_default_ipv4 = True
                    if "metric" in route:
                        if flavor == "rhel":
                            if subnet_is_ipv6(subnet):
                                iface_cfg["IPV6_ROUTE_METRIC"] = route[
                                    "metric"
                                ]
                            else:
                                iface_cfg["IPV4_ROUTE_METRIC"] = route[
                                    "metric"
                                ]
                        else:
                            iface_cfg["METRIC"] = route["metric"]

                else:
                    # add default routes only to ifcfg files, not
                    # to route-* or route6-*
                    for old_key, new_name in [
                        ("gateway", "GATEWAY"),
                        ("metric", "METRIC"),
                        ("prefix", "PREFIX"),
                        ("netmask", "NETMASK"),
                        ("network", "ADDRESS"),
                    ]:
                        if old_key in route:
                            new_key = f"{new_name}{route_cfg.last_idx}"
                            route_cfg[new_key] = route[old_key]
                    route_cfg.last_idx += 1

    @classmethod
    def _render_bonding_opts(cls, iface_cfg, iface, flavor):
        bond_opts = []
        for bond_key, value_tpl in cls.bond_tpl_opts:
            # Seems like either dash or underscore is possible?
            bond_keys = [bond_key, bond_key.replace("_", "-")]
            for bond_key in bond_keys:
                if bond_key in iface:
                    bond_value = iface[bond_key]
                    if isinstance(bond_value, (tuple, list)):
                        bond_value = " ".join(bond_value)
                    bond_opts.append(value_tpl % (bond_value))
                    break
        if bond_opts:
            if flavor == "suse":
                # suse uses the sysconfig support which requires
                # BONDING_MODULE_OPTS see
                # https://www.kernel.org/doc/Documentation/networking/bonding.txt
                # 3.1 Configuration with Sysconfig Support
                iface_cfg["BONDING_MODULE_OPTS"] = " ".join(bond_opts)
            else:
                # rhel uses initscript support and thus requires BONDING_OPTS
                # this is also the old default see
                # https://www.kernel.org/doc/Documentation/networking/bonding.txt
                #  3.2 Configuration with Initscripts Support
                iface_cfg["BONDING_OPTS"] = " ".join(bond_opts)

    @classmethod
    def _render_physical_interfaces(
        cls, network_state, iface_contents, flavor
    ):
        physical_filter = renderer.filter_by_physical
        for iface in network_state.iter_interfaces(physical_filter):
            iface_name = iface.get("config_id") or iface["name"]
            iface_subnets = iface.get("subnets", [])
            iface_cfg = iface_contents[iface_name]
            route_cfg = iface_cfg.routes

            cls._render_subnets(
                iface_cfg,
                iface_subnets,
                network_state.has_default_route,
                flavor,
            )
            cls._render_subnet_routes(
                iface_cfg, route_cfg, iface_subnets, flavor
            )

    @classmethod
    def _render_bond_interfaces(cls, network_state, iface_contents, flavor):
        bond_filter = renderer.filter_by_type("bond")
        slave_filter = renderer.filter_by_attr("bond-master")
        for iface in network_state.iter_interfaces(bond_filter):
            iface_name = iface["name"]
            iface_cfg = iface_contents[iface_name]
            cls._render_bonding_opts(iface_cfg, iface, flavor)

            # Ensure that the master interface (and any of its children)
            # are actually marked as being bond types...
            master_cfgs = [iface_cfg]
            master_cfgs.extend(iface_cfg.children)
            for master_cfg in master_cfgs:
                master_cfg["BONDING_MASTER"] = True
                if flavor != "suse":
                    master_cfg.kind = "bond"

            if iface.get("mac_address"):
                if flavor == "suse":
                    iface_cfg["LLADDR"] = iface.get("mac_address")
                else:
                    iface_cfg["MACADDR"] = iface.get("mac_address")

            iface_subnets = iface.get("subnets", [])
            route_cfg = iface_cfg.routes
            cls._render_subnets(
                iface_cfg,
                iface_subnets,
                network_state.has_default_route,
                flavor,
            )
            cls._render_subnet_routes(
                iface_cfg, route_cfg, iface_subnets, flavor
            )

            # iter_interfaces on network-state is not sorted to produce
            # consistent numbers we need to sort.
            bond_slaves = sorted(
                [
                    slave_iface["name"]
                    for slave_iface in network_state.iter_interfaces(
                        slave_filter
                    )
                    if slave_iface["bond-master"] == iface_name
                ]
            )

            for index, bond_slave in enumerate(bond_slaves):
                if flavor == "suse":
                    slavestr = "BONDING_SLAVE_%s" % index
                else:
                    slavestr = "BONDING_SLAVE%s" % index
                iface_cfg[slavestr] = bond_slave

                slave_cfg = iface_contents[bond_slave]
                if flavor == "suse":
                    slave_cfg["BOOTPROTO"] = "none"
                    slave_cfg["STARTMODE"] = "hotplug"
                else:
                    slave_cfg["MASTER"] = iface_name
                    slave_cfg["SLAVE"] = True

    @classmethod
    def _render_vlan_interfaces(cls, network_state, iface_contents, flavor):
        vlan_filter = renderer.filter_by_type("vlan")
        for iface in network_state.iter_interfaces(vlan_filter):
            iface_name = iface["name"]
            iface_cfg = iface_contents[iface_name]
            if flavor == "suse":
                vlan_id = iface.get("vlan_id")
                if vlan_id:
                    iface_cfg["VLAN_ID"] = vlan_id
                iface_cfg["ETHERDEVICE"] = iface_name[: iface_name.rfind(".")]
            else:
                iface_cfg["VLAN"] = True
                iface_cfg.kind = "vlan"

                rdev = iface["vlan-raw-device"]
                supported = _supported_vlan_names(rdev, iface["vlan_id"])
                if iface_name not in supported:
                    LOG.info(
                        "Name '%s' for vlan '%s' is not officially supported"
                        "by RHEL. Supported: %s",
                        iface_name,
                        rdev,
                        " ".join(supported),
                    )
                iface_cfg["PHYSDEV"] = rdev

            iface_subnets = iface.get("subnets", [])
            route_cfg = iface_cfg.routes
            cls._render_subnets(
                iface_cfg,
                iface_subnets,
                network_state.has_default_route,
                flavor,
            )
            cls._render_subnet_routes(
                iface_cfg, route_cfg, iface_subnets, flavor
            )

    @staticmethod
    def _render_dns(network_state, existing_dns_path=None):

        found_nameservers = []
        found_dns_search = []

        for iface in network_state.iter_interfaces():
            for subnet in iface["subnets"]:
                # Add subnet-level DNS
                if "dns_nameservers" in subnet:
                    found_nameservers.extend(subnet["dns_nameservers"])
                if "dns_search" in subnet:
                    found_dns_search.extend(subnet["dns_search"])

            # Add interface-level DNS
            if "dns" in iface:
                found_nameservers += [
                    dns
                    for dns in iface["dns"]["nameservers"]
                    if dns not in found_nameservers
                ]
                found_dns_search += [
                    search
                    for search in iface["dns"]["search"]
                    if search not in found_dns_search
                ]

        # When both global and interface specific entries are present,
        # use them both to generate /etc/resolv.conf eliminating duplicate
        # entries. Otherwise use global or interface specific entries whichever
        # is provided.
        if network_state.dns_nameservers:
            found_nameservers += [
                nameserver
                for nameserver in network_state.dns_nameservers
                if nameserver not in found_nameservers
            ]
        if network_state.dns_searchdomains:
            found_dns_search += [
                search
                for search in network_state.dns_searchdomains
                if search not in found_dns_search
            ]

        # skip writing resolv.conf if no dns information is provided in conf.
        if not any(
            [
                len(found_nameservers),
                len(found_dns_search),
            ]
        ):
            return None
        content = resolv_conf.ResolvConf("")
        if existing_dns_path and os.path.isfile(existing_dns_path):
            content = resolv_conf.ResolvConf(
                util.load_text_file(existing_dns_path)
            )
        for nameserver in found_nameservers:
            content.add_nameserver(nameserver)
        for searchdomain in found_dns_search:
            content.add_search_domain(searchdomain)
        header = _make_header(";")
        content_str = str(content)
        if not content_str.startswith(header):
            content_str = header + "\n" + content_str
        return content_str

    @staticmethod
    def _render_networkmanager_conf(network_state, templates=None):
        iface_dns = False
        content = networkmanager_conf.NetworkManagerConf("")
        # check if there is interface specific DNS information configured
        for iface in network_state.iter_interfaces():
            for subnet in iface["subnets"]:
                if "dns_nameservers" in subnet or "dns_search" in subnet:
                    iface_dns = True
                    break
            if (
                not iface_dns
                and "dns" in iface
                and (iface["dns"]["nameservers"] or iface["dns"]["search"])
            ):
                iface_dns = True
                break

        # If DNS server and/or dns search information is provided either
        # globally or per interface basis, configure NetworkManager to
        # not manage dns, so that /etc/resolv.conf does not get clobbered.
        # This is not required for NetworkManager renderer as it
        # does not write /etc/resolv.conf directly. DNS information is
        # written to the interface keyfile and NetworkManager is then
        # responsible for using the DNS information from the keyfile,
        # including managing /etc/resolv.conf.
        if (
            network_state.dns_nameservers
            or network_state.dns_searchdomains
            or iface_dns
        ):
            content.set_section_keypair("main", "dns", "none")

        if len(content) == 0:
            return None
        out = "".join([_make_header(), "\n", "\n".join(content.write()), "\n"])
        return out

    @classmethod
    def _render_bridge_interfaces(
        cls, network_state: NetworkState, iface_contents, flavor
    ):
        bridge_key_map = {
            old_k: new_k
            for old_k, new_k in cls.cfg_key_maps[flavor].items()
            if old_k.startswith("bridge")
        }
        bridge_filter = renderer.filter_by_type("bridge")

        for iface in network_state.iter_interfaces(bridge_filter):
            iface_name = iface["name"]
            iface_cfg = iface_contents[iface_name]
            if flavor != "suse":
                iface_cfg.kind = "bridge"
            for old_key, new_key in bridge_key_map.items():
                if old_key in iface:
                    iface_cfg[new_key] = iface[old_key]

            if flavor == "suse":
                if "BRIDGE_STP" in iface_cfg:
                    if iface_cfg.get("BRIDGE_STP"):
                        iface_cfg["BRIDGE_STP"] = "on"
                    else:
                        iface_cfg["BRIDGE_STP"] = "off"

            if iface.get("mac_address"):
                key = "MACADDR"
                if flavor == "suse":
                    key = "LLADDRESS"
                iface_cfg[key] = iface.get("mac_address")

            if flavor == "suse":
                if iface.get("bridge_ports", []):
                    iface_cfg["BRIDGE_PORTS"] = "%s" % " ".join(
                        iface.get("bridge_ports")
                    )
            # Is this the right key to get all the connected interfaces?
            for bridged_iface_name in iface.get("bridge_ports", []):
                # Ensure all bridged interfaces are correctly tagged
                # as being bridged to this interface.
                bridged_cfg = iface_contents[bridged_iface_name]
                bridged_cfgs = [bridged_cfg]
                bridged_cfgs.extend(bridged_cfg.children)
                for bridge_cfg in bridged_cfgs:
                    bridge_value = iface_name
                    if flavor == "suse":
                        bridge_value = "yes"
                    bridge_cfg["BRIDGE"] = bridge_value

            iface_subnets = iface.get("subnets", [])
            route_cfg = iface_cfg.routes
            cls._render_subnets(
                iface_cfg,
                iface_subnets,
                network_state.has_default_route,
                flavor,
            )
            cls._render_subnet_routes(
                iface_cfg, route_cfg, iface_subnets, flavor
            )

    @classmethod
    def _render_ib_interfaces(cls, network_state, iface_contents, flavor):
        ib_filter = renderer.filter_by_type("infiniband")
        for iface in network_state.iter_interfaces(ib_filter):
            iface_name = iface["name"]
            iface_cfg = iface_contents[iface_name]
            iface_cfg.kind = "infiniband"
            iface_subnets = iface.get("subnets", [])
            route_cfg = iface_cfg.routes
            cls._render_subnets(
                iface_cfg,
                iface_subnets,
                network_state.has_default_route,
                flavor,
            )
            cls._render_subnet_routes(
                iface_cfg, route_cfg, iface_subnets, flavor
            )

    @classmethod
    def _render_sysconfig(
        cls,
        base_sysconf_dir,
        network_state: NetworkState,
        flavor,
        templates=None,
    ):
        """Given state, return /etc/sysconfig files + contents"""
        if not templates:
            templates = cls.templates
        iface_contents: Dict[str, NetInterface] = {}
        for iface in network_state.iter_interfaces():
            if iface["type"] == "loopback":
                continue
            config_id: str = iface.get("config_id") or iface["name"]
            iface_cfg = NetInterface(
                iface["name"], base_sysconf_dir, templates
            )
            if flavor == "suse":
                iface_cfg.drop("DEVICE")
                # If type detection fails it is considered a bug in SUSE
                iface_cfg.drop("TYPE")
            cls._render_iface_shared(iface, iface_cfg, flavor)
            iface_contents[config_id] = iface_cfg
        cls._render_physical_interfaces(network_state, iface_contents, flavor)
        cls._render_bond_interfaces(network_state, iface_contents, flavor)
        cls._render_vlan_interfaces(network_state, iface_contents, flavor)
        cls._render_bridge_interfaces(network_state, iface_contents, flavor)
        cls._render_ib_interfaces(network_state, iface_contents, flavor)
        contents = {}
        for iface_name, iface_cfg in iface_contents.items():
            if iface_cfg or iface_cfg.children:
                contents[iface_cfg.path] = iface_cfg.to_string()
                for iface_cfg in iface_cfg.children:
                    if iface_cfg:
                        contents[iface_cfg.path] = iface_cfg.to_string()
            if iface_cfg.routes:
                for cpath, proto in zip(
                    [iface_cfg.routes.path_ipv4, iface_cfg.routes.path_ipv6],
                    ["ipv4", "ipv6"],
                ):
                    if cpath not in contents:
                        contents[cpath] = iface_cfg.routes.to_string(proto)
        return contents

    def render_network_state(
        self,
        network_state: NetworkState,
        templates: Optional[dict] = None,
        target=None,
    ) -> None:
        if not templates:
            templates = self.templates
        file_mode = 0o644
        base_sysconf_dir = subp.target_path(target, self.sysconf_dir)
        for path, data in self._render_sysconfig(
            base_sysconf_dir, network_state, self.flavor, templates=templates
        ).items():
            util.write_file(path, data, file_mode)
        if self.dns_path:
            dns_path = subp.target_path(target, self.dns_path)
            resolv_content = self._render_dns(
                network_state, existing_dns_path=dns_path
            )
            if resolv_content:
                util.write_file(dns_path, resolv_content, file_mode)
        if self.networkmanager_conf_path:
            nm_conf_path = subp.target_path(
                target, self.networkmanager_conf_path
            )
            nm_conf_content = self._render_networkmanager_conf(
                network_state, templates
            )
            if nm_conf_content:
                util.write_file(nm_conf_path, nm_conf_content, file_mode)
        if self.netrules_path:
            netrules_content = self._render_persistent_net(network_state)
            netrules_path = subp.target_path(target, self.netrules_path)
            util.write_file(
                netrules_path,
                content=netrules_content,
                mode=file_mode,
                preserve_mode=True,
            )

        sysconfig_path = subp.target_path(target, templates.get("control"))
        # Distros configuring /etc/sysconfig/network as a file e.g. Centos
        if sysconfig_path.endswith("network"):
            util.ensure_dir(os.path.dirname(sysconfig_path))
            netcfg = [_make_header(), "NETWORKING=yes"]
            if network_state.use_ipv6:
                netcfg.append("NETWORKING_IPV6=yes")
                netcfg.append("IPV6_AUTOCONF=no")

            # if sysconfig file exists and is not empty, append rest of the
            # file content, do not remove the exsisting customizations.
            if os.path.exists(sysconfig_path):
                for line in util.load_text_file(sysconfig_path).splitlines():
                    if (
                        not any(
                            setting in line
                            for setting in [
                                "NETWORKING",
                                "NETWORKING_IPV6",
                                "IPV6_AUTOCONF",
                            ]
                        )
                        and line not in _make_header().splitlines()
                    ):
                        netcfg.append(line)

            util.write_file(
                sysconfig_path, "\n".join(netcfg) + "\n", file_mode
            )


def _supported_vlan_names(rdev, vid):
    """Return list of supported names for vlan devices per RHEL doc
    11.5. Naming Scheme for VLAN Interfaces."""
    return [
        v.format(rdev=rdev, vid=int(vid))
        for v in (
            "{rdev}{vid:04}",
            "{rdev}{vid}",
            "{rdev}.{vid:04}",
            "{rdev}.{vid}",
        )
    ]


def available(target=None):
    if util.system_info()["variant"] not in KNOWN_DISTROS:
        return False
    if available_sysconfig(target):
        return True
    if available_nm_ifcfg_rh(target):
        return True
    return False


def available_nm_ifcfg_rh(target=None):
    # The ifcfg-rh plugin of NetworkManager is installed.
    # NetworkManager can handle the ifcfg files.
    return glob.glob(
        subp.target_path(
            target,
            "usr/lib*/NetworkManager/*/libnm-settings-plugin-ifcfg-rh.so",
        )
    )


def available_sysconfig(target=None):
    expected = ["ifup", "ifdown"]
    search = ["/sbin", "/usr/sbin"]
    for p in expected:
        if not subp.which(p, search=search, target=target):
            return False

    expected_paths = [
        "etc/sysconfig/network-scripts/network-functions",
        "etc/sysconfig/config",
    ]
    for p in expected_paths:
        if os.path.isfile(subp.target_path(target, p)):
            return True
    return False
