Merge branch 'interface-rewrite' of github.com:c-po/vyos-1x into current

* 'interface-rewrite' of github.com:c-po/vyos-1x:
  vyos.configverify: T2653: fix some formatting issues
  ifconfig: T2653: make ifname an optional argument to get_interface_dict()
  vyos.configdict: T2653: remove obsolete code from configdict and ifconfig_vlan
  wireless: ifconfig: T2653: move to get_config_dict()
  ifconfig: T2653: move get_ethertype() from configdict to interface
  vlan: ifconfig: T2653: move get_removed_vlans() to vyos.configdiff
  bonding: ifconfig: T2653: move to get_config_dict()
  ifconfig: T2653: move vlan configuration code to base class
  vyos.configdict: T2653: use dict_merge() over update()
  ifconfig: T2653: implement update() in derived classes for admin up/down
  vyos.configdict: T2653: add new reusable helper node_changed()
  geneve: ifconfig: T2653: move to get_config_dict()
  ifconfig: T2653: move bridge member check to base class
  interfaces: ifconfig: T2653: migrate to get_interface_dict() API
  pseudo-ethernet: ifconfig: T2653: move to get_config_dict()
  bridge: ifconfig: T2653: move to get_config_dict()
  vlan: ifconfig: T2653: only enable interface when lower interface is up
  ethernet: ifconfig: T2653: move to get_config_dict()
  ifconfig: T2653: set arp-cache-timeout default value of 30ms

13 files changed, 728 insertions, 663 deletions

diff --git a/python/vyos/configdict.py b/python/vyos/configdict.py
index 0dc7578d8..126d6195a 100644
--- a/python/vyos/configdict.py
+++ b/python/vyos/configdict.py
@@ -15,15 +15,15 @@
 
 """
 A library for retrieving value dicts from VyOS configs in a declarative fashion.
-
 """
+import os
+import jmespath
 
 from enum import Enum
 from copy import deepcopy
 
 from vyos import ConfigError
 from vyos.validate import is_member
-from vyos.util import ifname_from_config
 
 def retrieve_config(path_hash, base_path, config):
     """
@@ -102,397 +102,173 @@ def dict_merge(source, destination):
     return tmp
 
 def list_diff(first, second):
-    """
-    Diff two dictionaries and return only unique items
-    """
+    """ Diff two dictionaries and return only unique items """
     second = set(second)
     return [item for item in first if item not in second]
 
-
-def get_ethertype(ethertype_val):
-    if ethertype_val == '0x88A8':
-        return '802.1ad'
-    elif ethertype_val == '0x8100':
-        return '802.1q'
-    else:
-        raise ConfigError('invalid ethertype "{}"'.format(ethertype_val))
-
-dhcpv6_pd_default_data = {
-    'dhcpv6_prm_only': False,
-    'dhcpv6_temporary': False,
-    'dhcpv6_pd_length': '',
-    'dhcpv6_pd_interfaces': []
-}
-
-interface_default_data = {
-    **dhcpv6_pd_default_data,
-    'address': [],
-    'address_remove': [],
-    'description': '',
-    'dhcp_client_id': '',
-    'dhcp_hostname': '',
-    'dhcp_vendor_class_id': '',
-    'disable': False,
-    'disable_link_detect': 1,
-    'ip_disable_arp_filter': 1,
-    'ip_enable_arp_accept': 0,
-    'ip_enable_arp_announce': 0,
-    'ip_enable_arp_ignore': 0,
-    'ip_proxy_arp': 0,
-    'ipv6_accept_ra': 1,
-    'ipv6_autoconf': 0,
-    'ipv6_eui64_prefix': [],
-    'ipv6_eui64_prefix_remove': [],
-    'ipv6_forwarding': 1,
-    'ipv6_dup_addr_detect': 1,
-    'is_bridge_member': False,
-    'mac': '',
-    'mtu': 1500,
-    'vrf': ''
-}
-
-vlan_default = {
-    **interface_default_data,
-    'egress_qos': '',
-    'egress_qos_changed': False,
-    'ingress_qos': '',
-    'ingress_qos_changed': False,
-    'vif_c': {},
-    'vif_c_remove': []
-}
-
-# see: https://docs.python.org/3/library/enum.html#functional-api
-disable = Enum('disable','none was now both')
-
-def disable_state(conf, check=[3,5,7]):
+def T2665_default_dict_cleanup(dict):
+    """ Cleanup default keys for tag nodes https://phabricator.vyos.net/T2665. """
+    # Cleanup
+    for vif in ['vif', 'vif_s']:
+        if vif in dict.keys():
+            for key in ['ip', 'mtu']:
+                if key in dict[vif].keys():
+                    del dict[vif][key]
+
+            # cleanup VIF-S defaults
+            if 'vif_c' in dict[vif].keys():
+                for key in ['ip', 'mtu']:
+                    if key in dict[vif]['vif_c'].keys():
+                        del dict[vif]['vif_c'][key]
+                # If there is no vif-c defined and we just cleaned the default
+                # keys - we can clean the entire vif-c dict as it's useless
+                if not dict[vif]['vif_c']:
+                    del dict[vif]['vif_c']
+
+            # If there is no real vif/vif-s defined and we just cleaned the default
+            # keys - we can clean the entire vif dict as it's useless
+            if not dict[vif]:
+                del dict[vif]
+
+    return dict
+
+def leaf_node_changed(conf, path):
     """
-    return if and how a particual section of the configuration is has disable'd
-    using "disable" including if it was disabled by one of its parent.
-
-    check: a list of the level we should check, here 7,5 and 3
-          interfaces ethernet eth1 vif-s 1 vif-c 2 disable
-          interfaces ethernet eth1 vif 1 disable
-          interfaces ethernet eth1 disable
-
-    it returns an enum (none, was, now, both)
+    Check if a leaf node was altered. If it has been altered - values has been
+    changed, or it was added/removed, we will return the old value. If nothing
+    has been changed, None is returned
     """
-
-    # save where we are in the config
-    current_level = conf.get_level()
-
-    # logic to figure out if the interface (or one of it parent is disabled)
-    eff_disable = False
-    act_disable = False
-
-    levels = check[:]
-    working_level = current_level[:]
-
-    while levels:
-        position = len(working_level)
-        if not position:
-            break
-        if position not in levels:
-            working_level = working_level[:-1]
-            continue
-
-        levels.remove(position)
-        conf.set_level(working_level)
-        working_level = working_level[:-1]
-
-        eff_disable = eff_disable or conf.exists_effective('disable')
-        act_disable = act_disable or conf.exists('disable')
-
-    conf.set_level(current_level)
-
-    # how the disabling changed
-    if eff_disable and act_disable:
-        return disable.both
-    if eff_disable and not eff_disable:
-        return disable.was
-    if not eff_disable and act_disable:
-        return disable.now
-    return disable.none
-
-
-def intf_to_dict(conf, default):
-    from vyos.ifconfig import Interface
-
+    from vyos.configdiff import get_config_diff
+    D = get_config_diff(conf, key_mangling=('-', '_'))
+    D.set_level(conf.get_level())
+    (new, old) = D.get_value_diff(path)
+    if new != old:
+        if isinstance(old, str):
+            return old
+        elif isinstance(old, list):
+            if isinstance(new, str):
+                new = [new]
+            elif isinstance(new, type(None)):
+                new = []
+            return list_diff(old, new)
+
+    return None
+
+def node_changed(conf, path):
     """
-    Common used function which will extract VLAN related information from config
-    and represent the result as Python dictionary.
-
-    Function call's itself recursively if a vif-s/vif-c pair is detected.
+    Check if a leaf node was altered. If it has been altered - values has been
+    changed, or it was added/removed, we will return the old value. If nothing
+    has been changed, None is returned
     """
+    from vyos.configdiff import get_config_diff, Diff
+    D = get_config_diff(conf, key_mangling=('-', '_'))
+    D.set_level(conf.get_level())
+    # get_child_nodes() will return dict_keys(), mangle this into a list with PEP448
+    keys = D.get_child_nodes_diff(path, expand_nodes=Diff.DELETE)['delete'].keys()
+    return list(keys)
+
+def get_removed_vlans(conf, dict):
+    """
+    Common function to parse a dictionary retrieved via get_config_dict() and
+    determine any added/removed VLAN interfaces - be it 802.1q or Q-in-Q.
+    """
+    from vyos.configdiff import get_config_diff, Diff
 
-    intf = deepcopy(default)
-    intf['intf'] = ifname_from_config(conf)
-
-    current_vif_list = conf.list_nodes(['vif'])
-    previous_vif_list = conf.list_effective_nodes(['vif'])
-
-    # set the vif to be deleted
-    for vif in previous_vif_list:
-        if vif not in current_vif_list:
-            intf['vif_remove'].append(vif)
-
-    # retrieve interface description
-    if conf.exists(['description']):
-        intf['description'] = conf.return_value(['description'])
-
-    # get DHCP client identifier
-    if conf.exists(['dhcp-options', 'client-id']):
-        intf['dhcp_client_id'] = conf.return_value(['dhcp-options', 'client-id'])
-
-    # DHCP client host name (overrides the system host name)
-    if conf.exists(['dhcp-options', 'host-name']):
-        intf['dhcp_hostname'] = conf.return_value(['dhcp-options', 'host-name'])
-
-    # DHCP client vendor identifier
-    if conf.exists(['dhcp-options', 'vendor-class-id']):
-        intf['dhcp_vendor_class_id'] = conf.return_value(
-            ['dhcp-options', 'vendor-class-id'])
-
-    # DHCPv6 only acquire config parameters, no address
-    if conf.exists(['dhcpv6-options', 'parameters-only']):
-        intf['dhcpv6_prm_only'] = True
-
-    # DHCPv6 prefix delegation (RFC3633)
-    current_level = conf.get_level()
-    if conf.exists(['dhcpv6-options', 'prefix-delegation']):
-        dhcpv6_pd_path = current_level + ['dhcpv6-options', 'prefix-delegation']
-        conf.set_level(dhcpv6_pd_path)
-
-        # retriebe DHCPv6-PD prefix helper length as some ISPs only hand out a
-        # /64 by default (https://phabricator.vyos.net/T2506)
-        if conf.exists(['length']):
-            intf['dhcpv6_pd_length'] = conf.return_value(['length'])
+    # Check vif, vif-s/vif-c VLAN interfaces for removal
+    D = get_config_diff(conf, key_mangling=('-', '_'))
+    D.set_level(conf.get_level())
+    # get_child_nodes() will return dict_keys(), mangle this into a list with PEP448
+    keys = D.get_child_nodes_diff(['vif'], expand_nodes=Diff.DELETE)['delete'].keys()
+    if keys:
+        dict.update({'vif_remove': [*keys]})
 
-        for interface in conf.list_nodes(['interface']):
-            conf.set_level(dhcpv6_pd_path + ['interface', interface])
-            pd = {
-                'ifname': interface,
-                'sla_id': '',
-                'sla_len': '',
-                'if_id': ''
-            }
+    # get_child_nodes() will return dict_keys(), mangle this into a list with PEP448
+    keys = D.get_child_nodes_diff(['vif-s'], expand_nodes=Diff.DELETE)['delete'].keys()
+    if keys:
+        dict.update({'vif_s_remove': [*keys]})
 
-            if conf.exists(['sla-id']):
-                pd['sla_id'] = conf.return_value(['sla-id'])
+    for vif in dict.get('vif_s', {}).keys():
+        keys = D.get_child_nodes_diff(['vif-s', vif, 'vif-c'], expand_nodes=Diff.DELETE)['delete'].keys()
+        if keys:
+            dict.update({'vif_s': { vif : {'vif_c_remove': [*keys]}}})
 
-            if conf.exists(['sla-len']):
-                pd['sla_len'] = conf.return_value(['sla-len'])
+    return dict
 
-            if conf.exists(['address']):
-                pd['if_id'] = conf.return_value(['address'])
-
-            intf['dhcpv6_pd_interfaces'].append(pd)
-
-    # re-set config level
-    conf.set_level(current_level)
-
-    # DHCPv6 temporary IPv6 address
-    if conf.exists(['dhcpv6-options', 'temporary']):
-        intf['dhcpv6_temporary'] = True
-
-    # ignore link state changes
-    if conf.exists(['disable-link-detect']):
-        intf['disable_link_detect'] = 2
-
-    # ARP filter configuration
-    if conf.exists(['ip', 'disable-arp-filter']):
-        intf['ip_disable_arp_filter'] = 0
-
-    # ARP enable accept
-    if conf.exists(['ip', 'enable-arp-accept']):
-        intf['ip_enable_arp_accept'] = 1
-
-    # ARP enable announce
-    if conf.exists(['ip', 'enable-arp-announce']):
-        intf['ip_enable_arp_announce'] = 1
-
-    # ARP enable ignore
-    if conf.exists(['ip', 'enable-arp-ignore']):
-        intf['ip_enable_arp_ignore'] = 1
-
-    # Enable Proxy ARP
-    if conf.exists(['ip', 'enable-proxy-arp']):
-        intf['ip_proxy_arp'] = 1
-
-    # Enable acquisition of IPv6 address using stateless autoconfig (SLAAC)
-    if conf.exists(['ipv6', 'address', 'autoconf']):
-        intf['ipv6_autoconf'] = 1
-
-    # Disable IPv6 forwarding on this interface
-    if conf.exists(['ipv6', 'disable-forwarding']):
-        intf['ipv6_forwarding'] = 0
-
-    # check if interface is member of a bridge
-    intf['is_bridge_member'] = is_member(conf, intf['intf'], 'bridge')
-
-    # IPv6 Duplicate Address Detection (DAD) tries
-    if conf.exists(['ipv6', 'dup-addr-detect-transmits']):
-        intf['ipv6_dup_addr_detect'] = int(
-            conf.return_value(['ipv6', 'dup-addr-detect-transmits']))
-
-    # Media Access Control (MAC) address
-    if conf.exists(['mac']):
-        intf['mac'] = conf.return_value(['mac'])
-
-    # Maximum Transmission Unit (MTU)
-    if conf.exists(['mtu']):
-        intf['mtu'] = int(conf.return_value(['mtu']))
-
-    # retrieve VRF instance
-    if conf.exists(['vrf']):
-        intf['vrf'] = conf.return_value(['vrf'])
-
-    #  egress QoS
-    if conf.exists(['egress-qos']):
-        intf['egress_qos'] = conf.return_value(['egress-qos'])
-
-    # egress changes QoS require VLAN interface recreation
-    if conf.return_effective_value(['egress-qos']):
-        if intf['egress_qos'] != conf.return_effective_value(['egress-qos']):
-            intf['egress_qos_changed'] = True
-
-    # ingress QoS
-    if conf.exists(['ingress-qos']):
-        intf['ingress_qos'] = conf.return_value(['ingress-qos'])
-
-    # ingress changes QoS require VLAN interface recreation
-    if conf.return_effective_value(['ingress-qos']):
-        if intf['ingress_qos'] != conf.return_effective_value(['ingress-qos']):
-            intf['ingress_qos_changed'] = True
-
-    # Get the interface addresses
-    intf['address'] = conf.return_values(['address'])
-
-    # addresses to remove - difference between effective and working config
-    intf['address_remove'] = list_diff(
-            conf.return_effective_values(['address']), intf['address'])
-
-    # Get prefixes for IPv6 addressing based on MAC address (EUI-64)
-    intf['ipv6_eui64_prefix'] = conf.return_values(['ipv6', 'address', 'eui64'])
-
-    # EUI64 to remove - difference between effective and working config
-    intf['ipv6_eui64_prefix_remove'] = list_diff(
-            conf.return_effective_values(['ipv6', 'address', 'eui64']),
-            intf['ipv6_eui64_prefix'])
-
-    # Determine if the interface should be disabled
-    disabled = disable_state(conf)
-    if disabled == disable.both:
-        # was and is still disabled
-        intf['disable'] = True
-    elif disabled == disable.now:
-        # it is now disable but was not before
-        intf['disable'] = True
-    elif disabled == disable.was:
-        # it was disable but not anymore
-        intf['disable'] = False
-    else:
-        # normal change
-        intf['disable'] = False
-
-    # Remove the default link-local address if no-default-link-local is set,
-    # if member of a bridge or if disabled (it may not have a MAC if it's down)
-    if ( conf.exists(['ipv6', 'address', 'no-default-link-local'])
-            or intf.get('is_bridge_member') or intf['disable'] ):
-        intf['ipv6_eui64_prefix_remove'].append('fe80::/64')
-    else:
-        # add the link-local by default to make IPv6 work
-        intf['ipv6_eui64_prefix'].append('fe80::/64')
-
-    # If MAC has changed, remove and re-add all IPv6 EUI64 addresses
-    try:
-        interface = Interface(intf['intf'], create=False)
-        if intf['mac'] and intf['mac'] != interface.get_mac():
-            intf['ipv6_eui64_prefix_remove'] += intf['ipv6_eui64_prefix']
-    except Exception:
-        # If the interface does not exist, it could not have changed
-        pass
-
-    # to make IPv6 SLAAC and DHCPv6 work with forwarding=1,
-    # accept_ra must be 2
-    if intf['ipv6_autoconf'] or 'dhcpv6' in intf['address']:
-        intf['ipv6_accept_ra'] = 2
-
-    return intf, disable
-
-
-
-def add_to_dict(conf, disabled, ifdict, section, key):
+def get_interface_dict(config, base, ifname=''):
     """
-    parse a section of vif/vif-s/vif-c and add them to the dict
-    follow the convention to:
-    * use the "key" for what to add
-    * use the "key" what what to remove
-
-    conf:     is the Config() already at the level we need to parse
-    disabled: is a disable enum so we know how to handle to data
-    intf:     if the interface dictionary
-    section:  is the section name to parse (vif/vif-s/vif-c)
-    key:      is the dict key to use (vif/vifs/vifc)
+    Common utility function to retrieve and mandgle the interfaces available
+    in CLI configuration. All interfaces have a common base ground where the
+    value retrival is identical - so it can and should be reused
+
+    Will return a dictionary with the necessary interface configuration
     """
+    from vyos.xml import defaults
+
+    if not ifname:
+        # determine tagNode instance
+        if 'VYOS_TAGNODE_VALUE' not in os.environ:
+            raise ConfigError('Interface (VYOS_TAGNODE_VALUE) not specified')
+        ifname = os.environ['VYOS_TAGNODE_VALUE']
+
+    # retrieve interface default values
+    default_values = defaults(base)
+
+    # setup config level which is extracted in get_removed_vlans()
+    config.set_level(base + [ifname])
+    dict = config.get_config_dict([], key_mangling=('-', '_'), get_first_key=True)
+
+    # Check if interface has been removed
+    if dict == {}:
+        dict.update({'deleted' : ''})
+
+    # Add interface instance name into dictionary
+    dict.update({'ifname': ifname})
+
+    # We have gathered the dict representation of the CLI, but there are
+    # default options which we need to update into the dictionary
+    # retrived.
+    dict = dict_merge(default_values, dict)
+
+    # Check if we are a member of a bridge device
+    bridge = is_member(config, ifname, 'bridge')
+    if bridge:
+        dict.update({'is_bridge_member' : bridge})
+
+    # Check if we are a member of a bond device
+    bond = is_member(config, ifname, 'bonding')
+    if bond:
+        dict.update({'is_bond_member' : bond})
+
+    mac = leaf_node_changed(config, ['mac'])
+    if mac:
+        dict.update({'mac_old' : mac})
+
+    eui64 = leaf_node_changed(config, ['ipv6', 'address', 'eui64'])
+    if eui64:
+        # XXX: T2636 workaround: convert string to a list with one element
+        if isinstance(eui64, str):
+            eui64 = [eui64]
+        tmp = jmespath.search('ipv6.address', dict)
+        if not tmp:
+            dict.update({'ipv6': {'address': {'eui64_old': eui64}}})
+        else:
+            dict['ipv6']['address'].update({'eui64_old': eui64})
+
+    # remove wrongly inserted values
+    dict = T2665_default_dict_cleanup(dict)
+
+    # The values are identical for vif, vif-s and vif-c as the all include the same
+    # XML definitions which hold the defaults
+    default_vif_values = defaults(base + ['vif'])
+    for vif, vif_config in dict.get('vif', {}).items():
+        vif_config = dict_merge(default_vif_values, vif_config)
+    for vif_s, vif_s_config in dict.get('vif_s', {}).items():
+        vif_s_config = dict_merge(default_vif_values, vif_s_config)
+        for vif_c, vif_c_config in vif_s_config.get('vif_c', {}).items():
+            vif_c_config = dict_merge(default_vif_values, vif_c_config)
+
+    # Check vif, vif-s/vif-c VLAN interfaces for removal
+    dict = get_removed_vlans(config, dict)
+
+    return dict
 
-    if not conf.exists(section):
-        return ifdict
-
-    effect = conf.list_effective_nodes(section)
-    active = conf.list_nodes(section)
-
-    # the section to parse for vlan
-    sections = []
-
-    # determine which interfaces to add or remove based on disable state
-    if disabled == disable.both:
-        # was and is still disabled
-        ifdict[f'{key}_remove'] = []
-    elif disabled == disable.now:
-        # it is now disable but was not before
-        ifdict[f'{key}_remove'] = effect
-    elif disabled == disable.was:
-        # it was disable but not anymore
-        ifdict[f'{key}_remove'] = []
-        sections = active
-    else:
-        # normal change
-        # get interfaces (currently effective) - to determine which
-        # interface is no longer present and needs to be removed
-        ifdict[f'{key}_remove'] = list_diff(effect, active)
-        sections = active
-
-    current_level = conf.get_level()
-
-    # add each section, the key must already exists
-    for s in sections:
-        # set config level to vif interface
-        conf.set_level(current_level + [section, s])
-        # add the vlan config as a key (vlan id) - value (config) pair
-        ifdict[key][s] = vlan_to_dict(conf)
-
-    # re-set configuration level to leave things as found
-    conf.set_level(current_level)
-
-    return ifdict
-
-
-def vlan_to_dict(conf, default=vlan_default):
-    vlan, disabled = intf_to_dict(conf, default)
-
-    # if this is a not within vif-s node, we are done
-    if conf.get_level()[-2] != 'vif-s':
-        return vlan
-
-    # ethertype is mandatory on vif-s nodes and only exists here!
-    # ethertype uses a default of 0x88A8
-    tmp = '0x88A8'
-    if conf.exists('ethertype'):
-        tmp = conf.return_value('ethertype')
-    vlan['ethertype'] = get_ethertype(tmp)
-
-    # check if there is a Q-in-Q vlan customer interface
-    # and call this function recursively
-    add_to_dict(conf, disable, vlan, 'vif-c', 'vif_c')
-
-    return vlan
diff --git a/python/vyos/configverify.py b/python/vyos/configverify.py
index 32129a048..8e06d16f2 100644
--- a/python/vyos/configverify.py
+++ b/python/vyos/configverify.py
@@ -41,14 +41,14 @@ def verify_vrf(config):
 
 def verify_address(config):
     """
-    Common helper function used by interface implementations to
-    perform recurring validation of IP address assignmenr
-    when interface also is part of a bridge.
+    Common helper function used by interface implementations to perform
+    recurring validation of IP address assignment when interface is part
+    of a bridge or bond.
     """
     if {'is_bridge_member', 'address'} <= set(config):
         raise ConfigError(
-            f'Cannot assign address to interface "{ifname}" as it is a '
-            f'member of bridge "{is_bridge_member}"!'.format(**config))
+            'Cannot assign address to interface "{ifname}" as it is a '
+            'member of bridge "{is_bridge_member}"!'.format(**config))
 
 
 def verify_bridge_delete(config):
@@ -62,6 +62,15 @@ def verify_bridge_delete(config):
             'Interface "{ifname}" cannot be deleted as it is a '
             'member of bridge "{is_bridge_member}"!'.format(**config))
 
+def verify_interface_exists(config):
+    """
+    Common helper function used by interface implementations to perform
+    recurring validation if an interface actually exists.
+    """
+    from netifaces import interfaces
+    if not config['ifname'] in interfaces():
+        raise ConfigError(f'Interface "{ifname}" does not exist!'
+                          .format(**config))
 
 def verify_source_interface(config):
     """
@@ -70,9 +79,43 @@ def verify_source_interface(config):
     required by e.g. peth/MACvlan, MACsec ...
     """
     from netifaces import interfaces
-    if not 'source_interface' in config.keys():
+    if 'source_interface' not in config:
         raise ConfigError('Physical source-interface required for '
                           'interface "{ifname}"'.format(**config))
-    if not config['source_interface'] in interfaces():
-        raise ConfigError(f'Source interface {source_interface} does not '
-                          f'exist'.format(**config))
+    if config['source_interface'] not in interfaces():
+        raise ConfigError('Source interface {source_interface} does not '
+                          'exist'.format(**config))
+
+def verify_dhcpv6(config):
+    """
+    Common helper function used by interface implementations to perform
+    recurring validation of DHCPv6 options which are mutually exclusive.
+    """
+    if {'parameters_only', 'temporary'} <= set(config.get('dhcpv6_options', {})):
+        raise ConfigError('DHCPv6 temporary and parameters-only options '
+                          'are mutually exclusive!')
+
+def verify_vlan_config(config):
+    """
+    Common helper function used by interface implementations to perform
+    recurring validation of interface VLANs
+    """
+    # 802.1q VLANs
+    for vlan in config.get('vif', {}).keys():
+        vlan = config['vif'][vlan]
+        verify_dhcpv6(vlan)
+        verify_address(vlan)
+        verify_vrf(vlan)
+
+    # 802.1ad (Q-in-Q) VLANs
+    for vlan in config.get('vif_s', {}).keys():
+        vlan = config['vif_s'][vlan]
+        verify_dhcpv6(vlan)
+        verify_address(vlan)
+        verify_vrf(vlan)
+
+        for vlan in config.get('vif_s', {}).get('vif_c', {}).keys():
+            vlan = config['vif_c'][vlan]
+            verify_dhcpv6(vlan)
+            verify_address(vlan)
+            verify_vrf(vlan)
diff --git a/python/vyos/ifconfig/bond.py b/python/vyos/ifconfig/bond.py
index 47dd4ff34..5a48ac632 100644
--- a/python/vyos/ifconfig/bond.py
+++ b/python/vyos/ifconfig/bond.py
@@ -14,14 +14,15 @@
 # License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import jmespath
 
 from vyos.ifconfig.interface import Interface
 from vyos.ifconfig.vlan import VLAN
 
+from vyos.util import cmd
 from vyos.validate import assert_list
 from vyos.validate import assert_positive
 
-
 @Interface.register
 @VLAN.enable
 class BondIf(Interface):
@@ -179,7 +180,13 @@ class BondIf(Interface):
         >>> BondIf('bond0').get_arp_ip_target()
         '192.0.2.1'
         """
-        return self.get_interface('bond_arp_ip_target')
+        # As this function might also be called from update() of a VLAN interface
+        # we must check if the bond_arp_ip_target retrieval worked or not - as this
+        # can not be set for a bond vif interface
+        try:
+            return self.get_interface('bond_arp_ip_target')
+        except FileNotFoundError:
+            return ''
 
     def set_arp_ip_target(self, target):
         """
@@ -209,11 +216,31 @@ class BondIf(Interface):
         >>> BondIf('bond0').add_port('eth0')
         >>> BondIf('bond0').add_port('eth1')
         """
-        # An interface can only be added to a bond if it is in 'down' state. If
-        # interface is in 'up' state, the following Kernel error will  be thrown:
-        # bond0: eth1 is up - this may be due to an out of date ifenslave.
-        Interface(interface).set_admin_state('down')
-        return self.set_interface('bond_add_port', f'+{interface}')
+
+        # From drivers/net/bonding/bond_main.c:
+        # ...
+        # bond_set_slave_link_state(new_slave,
+        #      BOND_LINK_UP,
+        #      BOND_SLAVE_NOTIFY_NOW);
+        # ...
+        #
+        # The kernel will ALWAYS place new bond members in "up" state regardless
+        # what the CLI will tell us!
+
+        # Physical interface must be in admin down state before they can be
+        # enslaved. If this is not the case an error will be shown:
+        # bond0: eth0 is up - this may be due to an out of date ifenslave
+        slave = Interface(interface)
+        slave_state = slave.get_admin_state()
+        if slave_state == 'up':
+            slave.set_admin_state('down')
+
+        ret = self.set_interface('bond_add_port', f'+{interface}')
+        # The kernel will ALWAYS place new bond members in "up" state regardless
+        # what the LI is configured for - thus we place the interface in its
+        # desired state
+        slave.set_admin_state(slave_state)
+        return ret
 
     def del_port(self, interface):
         """
@@ -277,3 +304,80 @@ class BondIf(Interface):
         >>> BondIf('bond0').set_mode('802.3ad')
         """
         return self.set_interface('bond_mode', mode)
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # use ref-counting function to place an interface into admin down state.
+        # set_admin_state_up() must be called the same amount of times else the
+        # interface won't come up. This can/should be used to prevent link flapping
+        # when changing interface parameters require the interface to be down.
+        # We will disable it once before reconfiguration and enable it afterwards.
+        if 'shutdown_required' in config:
+            self.set_admin_state('down')
+
+        # call base class first
+        super().update(config)
+
+        # ARP monitor targets need to be synchronized between sysfs and CLI.
+        # Unfortunately an address can't be send twice to sysfs as this will
+        # result in the following exception:  OSError: [Errno 22] Invalid argument.
+        #
+        # We remove ALL addresses prior to adding new ones, this will remove
+        # addresses manually added by the user too - but as we are limited to 16 adresses
+        # from the kernel side this looks valid to me. We won't run into an error
+        # when a user added manual adresses which would result in having more
+        # then 16 adresses in total.
+        arp_tgt_addr = list(map(str, self.get_arp_ip_target().split()))
+        for addr in arp_tgt_addr:
+            self.set_arp_ip_target('-' + addr)
+
+        # Add configured ARP target addresses
+        value = jmespath.search('arp_monitor.target', config)
+        if isinstance(value, str):
+            value = [value]
+        if value:
+            for addr in value:
+                self.set_arp_ip_target('+' + addr)
+
+        # Bonding transmit hash policy
+        value = config.get('hash_policy')
+        if value: self.set_hash_policy(value)
+
+        # Some interface options can only be changed if the interface is
+        # administratively down
+        if self.get_admin_state() == 'down':
+            # Delete bond member port(s)
+            for interface in self.get_slaves():
+                self.del_port(interface)
+
+            # Bonding policy/mode
+            value = config.get('mode')
+            if value: self.set_mode(value)
+
+            # Add (enslave) interfaces to bond
+            value = jmespath.search('member.interface', config)
+            if value:
+                for interface in value:
+                    # if we've come here we already verified the interface does
+                    # not have an addresses configured so just flush any
+                    # remaining ones
+                    cmd(f'ip addr flush dev "{interface}"')
+                    self.add_port(interface)
+
+        # Primary device interface - must be set after 'mode'
+        value = config.get('primary')
+        if value: self.set_primary(value)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/bridge.py b/python/vyos/ifconfig/bridge.py
index 44b92c1db..da4e1a289 100644
--- a/python/vyos/ifconfig/bridge.py
+++ b/python/vyos/ifconfig/bridge.py
@@ -13,12 +13,13 @@
 # You should have received a copy of the GNU Lesser General Public
 # License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
+import jmespath
 
 from vyos.ifconfig.interface import Interface
-
+from vyos.ifconfig.stp import STP
 from vyos.validate import assert_boolean
 from vyos.validate import assert_positive
-
+from vyos.util import cmd
 
 @Interface.register
 class BridgeIf(Interface):
@@ -187,3 +188,76 @@ class BridgeIf(Interface):
         >>> BridgeIf('br0').del_port('eth1')
         """
         return self.set_interface('del_port', interface)
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # Set ageing time
+        value = config.get('aging')
+        self.set_ageing_time(value)
+
+        # set bridge forward delay
+        value = config.get('forwarding_delay')
+        self.set_forward_delay(value)
+
+        # set hello time
+        value = config.get('hello_time')
+        self.set_hello_time(value)
+
+        # set max message age
+        value = config.get('max_age')
+        self.set_max_age(value)
+
+        # set bridge priority
+        value = config.get('priority')
+        self.set_priority(value)
+
+        # enable/disable spanning tree
+        value = '1' if 'stp' in config else '0'
+        self.set_stp(value)
+
+        # enable or disable IGMP querier
+        tmp = jmespath.search('igmp.querier', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_multicast_querier(value)
+
+        # remove interface from bridge
+        tmp = jmespath.search('member.interface_remove', config)
+        if tmp:
+            for member in tmp:
+                self.del_port(member)
+
+        STPBridgeIf = STP.enable(BridgeIf)
+        tmp = jmespath.search('member.interface', config)
+        if tmp:
+            for interface, interface_config in tmp.items():
+                # if we've come here we already verified the interface doesn't
+                # have addresses configured so just flush any remaining ones
+                cmd(f'ip addr flush dev "{interface}"')
+                # enslave interface port to bridge
+                self.add_port(interface)
+
+                tmp = STPBridgeIf(interface)
+                # set bridge port path cost
+                value = interface_config.get('cost')
+                tmp.set_path_cost(value)
+
+                # set bridge port path priority
+                value = interface_config.get('priority')
+                tmp.set_path_priority(value)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/dummy.py b/python/vyos/ifconfig/dummy.py
index 404c490c7..43614cd1c 100644
--- a/python/vyos/ifconfig/dummy.py
+++ b/python/vyos/ifconfig/dummy.py
@@ -35,3 +35,22 @@ class DummyIf(Interface):
             'prefixes': ['dum', ],
         },
     }
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/ethernet.py b/python/vyos/ifconfig/ethernet.py
index 5b18926c9..b2f701e00 100644
--- a/python/vyos/ifconfig/ethernet.py
+++ b/python/vyos/ifconfig/ethernet.py
@@ -15,13 +15,13 @@
 
 import os
 import re
+import jmespath
 
 from vyos.ifconfig.interface import Interface
 from vyos.ifconfig.vlan import VLAN
 from vyos.validate import assert_list
 from vyos.util import run
 
-
 @Interface.register
 @VLAN.enable
 class EthernetIf(Interface):
@@ -252,3 +252,58 @@ class EthernetIf(Interface):
         >>> i.set_udp_offload('on')
         """
         return self.set_interface('ufo', state)
+
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # disable ethernet flow control (pause frames)
+        value = 'off' if 'disable_flow_control' in config.keys() else 'on'
+        self.set_flow_control(value)
+
+        # GRO (generic receive offload)
+        tmp = jmespath.search('offload_options.generic_receive', config)
+        value = tmp if (tmp != None) else 'off'
+        self.set_gro(value)
+
+        # GSO (generic segmentation offload)
+        tmp = jmespath.search('offload_options.generic_segmentation', config)
+        value = tmp if (tmp != None) else 'off'
+        self.set_gso(value)
+
+        # scatter-gather option
+        tmp = jmespath.search('offload_options.scatter_gather', config)
+        value = tmp if (tmp != None) else 'off'
+        self.set_sg(value)
+
+        # TSO (TCP segmentation offloading)
+        tmp = jmespath.search('offload_options.udp_fragmentation', config)
+        value = tmp if (tmp != None) else 'off'
+        self.set_tso(value)
+
+        # UDP fragmentation offloading
+        tmp = jmespath.search('offload_options.udp_fragmentation', config)
+        value = tmp if (tmp != None) else 'off'
+        self.set_ufo(value)
+
+        # Set physical interface speed and duplex
+        if {'speed', 'duplex'} <= set(config):
+            speed = config.get('speed')
+            duplex = config.get('duplex')
+            self.set_speed_duplex(speed, duplex)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/interface.py b/python/vyos/ifconfig/interface.py
index 8d7b247fc..5496499e5 100644
--- a/python/vyos/ifconfig/interface.py
+++ b/python/vyos/ifconfig/interface.py
@@ -16,7 +16,10 @@
 import os
 import re
 import json
+import jmespath
+
 from copy import deepcopy
+from glob import glob
 
 from ipaddress import IPv4Network
 from ipaddress import IPv6Address
@@ -45,6 +48,13 @@ from vyos.ifconfig.vrrp import VRRP
 from vyos.ifconfig.operational import Operational
 from vyos.ifconfig import Section
 
+def get_ethertype(ethertype_val):
+    if ethertype_val == '0x88A8':
+        return '802.1ad'
+    elif ethertype_val == '0x8100':
+        return '802.1q'
+    else:
+        raise ConfigError('invalid ethertype "{}"'.format(ethertype_val))
 
 class Interface(Control):
     # This is the class which will be used to create
@@ -72,8 +82,12 @@ class Interface(Control):
     _command_get = {
         'admin_state': {
             'shellcmd': 'ip -json link show dev {ifname}',
-            'format': lambda j: 'up' if 'UP' in json.loads(j)[0]['flags'] else 'down',
-        }
+            'format': lambda j: 'up' if 'UP' in jmespath.search('[*].flags | [0]', json.loads(j)) else 'down',
+        },
+        'vlan_protocol': {
+            'shellcmd': 'ip -json -details link show dev {ifname}',
+            'format': lambda j: jmespath.search('[*].linkinfo.info_data.protocol | [0]', json.loads(j)),
+        },
     }
 
     _command_set = {
@@ -197,6 +211,7 @@ class Interface(Control):
 
         # make sure the ifname is the first argument and not from the dict
         self.config['ifname'] = ifname
+        self._admin_state_down_cnt = 0
 
         # we must have updated config before initialising the Interface
         super().__init__(**kargs)
@@ -322,11 +337,11 @@ class Interface(Control):
             self.set_admin_state('down')
 
         self.set_interface('mac', mac)
-        
+
         # Turn an interface to the 'up' state if it was changed to 'down' by this fucntion
         if prev_state == 'up':
             self.set_admin_state('up')
-    
+
     def set_vrf(self, vrf=''):
         """
         Add/Remove interface from given VRF instance.
@@ -543,6 +558,17 @@ class Interface(Control):
         """
         self.set_interface('alias', ifalias)
 
+    def get_vlan_protocol(self):
+        """
+        Retrieve VLAN protocol in use, this can be 802.1Q, 802.1ad or None
+
+        Example:
+        >>> from vyos.ifconfig import Interface
+        >>> Interface('eth0.10').get_vlan_protocol()
+        '802.1Q'
+        """
+        return self.get_interface('vlan_protocol')
+
     def get_admin_state(self):
         """
         Get interface administrative state. Function will return 'up' or 'down'
@@ -564,7 +590,24 @@ class Interface(Control):
         >>> Interface('eth0').get_admin_state()
         'down'
         """
-        return self.set_interface('admin_state', state)
+        # A VLAN interface can only be placed in admin up state when
+        # the lower interface is up, too
+        if self.get_vlan_protocol():
+            lower_interface = glob(f'/sys/class/net/{self.ifname}/lower*/flags')[0]
+            with open(lower_interface, 'r') as f:
+                flags = f.read()
+            # If parent is not up - bail out as we can not bring up the VLAN.
+            # Flags are defined in kernel source include/uapi/linux/if.h
+            if not int(flags, 16) & 1:
+                return None
+
+        if state == 'up':
+            self._admin_state_down_cnt -= 1
+            if self._admin_state_down_cnt < 1:
+                return self.set_interface('admin_state', state)
+        else:
+            self._admin_state_down_cnt += 1
+            return self.set_interface('admin_state', state)
 
     def set_proxy_arp(self, enable):
         """
@@ -773,14 +816,17 @@ class Interface(Control):
         on any interface. """
 
         # Update interface description
-        self.set_alias(config.get('description', None))
+        self.set_alias(config.get('description', ''))
+
+        # Ignore link state changes
+        value = '2' if 'disable_link_detect' in config else '1'
+        self.set_link_detect(value)
 
         # Configure assigned interface IP addresses. No longer
         # configured addresses will be removed first
         new_addr = config.get('address', [])
 
-        # XXX workaround for T2636, convert IP address string to a list
-        # with one element
+        # XXX: T2636 workaround: convert string to a list with one element
         if isinstance(new_addr, str):
             new_addr = [new_addr]
 
@@ -796,10 +842,156 @@ class Interface(Control):
         # There are some items in the configuration which can only be applied
         # if this instance is not bound to a bridge. This should be checked
         # by the caller but better save then sorry!
-        if not config.get('is_bridge_member', False):
-            # Bind interface instance into VRF
+        if not any(k in ['is_bond_member', 'is_bridge_member'] for k in config):
+            # Bind interface to given VRF or unbind it if vrf node is not set.
+            # unbinding will call 'ip link set dev eth0 nomaster' which will
+            # also drop the interface out of a bridge or bond - thus this is
+            # checked before
             self.set_vrf(config.get('vrf', ''))
 
-        # Interface administrative state
-        state = 'down' if 'disable' in config.keys() else 'up'
-        self.set_admin_state(state)
+        # DHCP options
+        if 'dhcp_options' in config:
+            dhcp_options = config.get('dhcp_options')
+            if 'client_id' in dhcp_options:
+                self.dhcp.v4.options['client_id'] = dhcp_options.get('client_id')
+
+            if 'host_name' in dhcp_options:
+                self.dhcp.v4.options['hostname'] = dhcp_options.get('host_name')
+
+            if 'vendor_class_id' in dhcp_options:
+                self.dhcp.v4.options['vendor_class_id'] = dhcp_options.get('vendor_class_id')
+
+        # DHCPv6 options
+        if 'dhcpv6_options' in config:
+            dhcpv6_options = config.get('dhcpv6_options')
+            if 'parameters_only' in dhcpv6_options:
+                self.dhcp.v6.options['dhcpv6_prm_only'] = True
+
+            if 'temporary' in dhcpv6_options:
+                self.dhcp.v6.options['dhcpv6_temporary'] = True
+
+            if 'prefix_delegation' in dhcpv6_options:
+                prefix_delegation = dhcpv6_options.get('prefix_delegation')
+                if 'length' in prefix_delegation:
+                    self.dhcp.v6.options['dhcpv6_pd_length'] = prefix_delegation.get('length')
+
+                if 'interface' in prefix_delegation:
+                    self.dhcp.v6.options['dhcpv6_pd_interfaces'] = prefix_delegation.get('interface')
+
+        # Configure ARP cache timeout in milliseconds - has default value
+        tmp = jmespath.search('ip.arp_cache_timeout', config)
+        value = tmp if (tmp != None) else '30'
+        self.set_arp_cache_tmo(value)
+
+        # Configure ARP filter configuration
+        tmp = jmespath.search('ip.disable_arp_filter', config)
+        value = '0' if (tmp != None) else '1'
+        self.set_arp_filter(value)
+
+        # Configure ARP accept
+        tmp = jmespath.search('ip.enable_arp_accept', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_arp_accept(value)
+
+        # Configure ARP announce
+        tmp = jmespath.search('ip.enable_arp_announce', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_arp_announce(value)
+
+        # Configure ARP ignore
+        tmp = jmespath.search('ip.enable_arp_ignore', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_arp_ignore(value)
+
+        # Enable proxy-arp on this interface
+        tmp = jmespath.search('ip.enable_proxy_arp', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_proxy_arp(value)
+
+        # Enable private VLAN proxy ARP on this interface
+        tmp = jmespath.search('ip.proxy_arp_pvlan', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_proxy_arp_pvlan(value)
+
+        # IPv6 forwarding
+        tmp = jmespath.search('ipv6.disable_forwarding', config)
+        value = '0' if (tmp != None) else '1'
+        self.set_ipv6_forwarding(value)
+
+        # IPv6 router advertisements
+        tmp = jmespath.search('ipv6.address.autoconf', config)
+        value = '2' if (tmp != None) else '1'
+        if 'dhcpv6' in new_addr:
+            value = '2'
+        self.set_ipv6_accept_ra(value)
+
+        # IPv6 address autoconfiguration
+        tmp = jmespath.search('ipv6.address.autoconf', config)
+        value = '1' if (tmp != None) else '0'
+        self.set_ipv6_autoconf(value)
+
+        # IPv6 Duplicate Address Detection (DAD) tries
+        tmp = jmespath.search('ipv6.dup_addr_detect_transmits', config)
+        value = tmp if (tmp != None) else '1'
+        self.set_ipv6_dad_messages(value)
+
+        # MTU - Maximum Transfer Unit
+        if 'mtu' in config:
+            self.set_mtu(config.get('mtu'))
+
+        # Delete old IPv6 EUI64 addresses before changing MAC
+        tmp = jmespath.search('ipv6.address.eui64_old', config)
+        if tmp:
+            for addr in tmp:
+                self.del_ipv6_eui64_address(addr)
+
+        # Change interface MAC address - re-set to real hardware address (hw-id)
+        # if custom mac is removed. Skip if bond member.
+        if 'is_bond_member' not in config:
+            mac = config.get('hw_id')
+            if 'mac' in config:
+                mac = config.get('mac')
+            if mac:
+                self.set_mac(mac)
+
+        # Add IPv6 EUI-based addresses
+        tmp = jmespath.search('ipv6.address.eui64', config)
+        if tmp:
+            # XXX: T2636 workaround: convert string to a list with one element
+            if isinstance(tmp, str):
+                tmp = [tmp]
+            for addr in tmp:
+                self.add_ipv6_eui64_address(addr)
+
+        # re-add ourselves to any bridge we might have fallen out of
+        if 'is_bridge_member' in config:
+            bridge = config.get('is_bridge_member')
+            self.add_to_bridge(bridge)
+
+        # remove no longer required 802.1ad (Q-in-Q VLANs)
+        for vif_s_id in config.get('vif_s_remove', {}):
+            self.del_vlan(vif_s_id)
+
+        # create/update 802.1ad (Q-in-Q VLANs)
+        for vif_s_id, vif_s in config.get('vif_s', {}).items():
+            tmp=get_ethertype(vif_s.get('ethertype', '0x88A8'))
+            s_vlan = self.add_vlan(vif_s_id, ethertype=tmp)
+            s_vlan.update(vif_s)
+
+            # remove no longer required client VLAN (vif-c)
+            for vif_c_id in vif_s.get('vif_c_remove', {}):
+                s_vlan.del_vlan(vif_c_id)
+
+            # create/update client VLAN (vif-c) interface
+            for vif_c_id, vif_c in vif_s.get('vif_c', {}).items():
+                c_vlan = s_vlan.add_vlan(vif_c_id)
+                c_vlan.update(vif_c)
+
+        # remove no longer required 802.1q VLAN interfaces
+        for vif_id in config.get('vif_remove', {}):
+            self.del_vlan(vif_id)
+
+        # create/update 802.1q VLAN interfaces
+        for vif_id, vif in config.get('vif', {}).items():
+            vlan = self.add_vlan(vif_id)
+            vlan.update(vif)
diff --git a/python/vyos/ifconfig/loopback.py b/python/vyos/ifconfig/loopback.py
index 7ebd13b54..2b4ebfdcc 100644
--- a/python/vyos/ifconfig/loopback.py
+++ b/python/vyos/ifconfig/loopback.py
@@ -75,5 +75,15 @@ class LoopbackIf(Interface):
         # Update IP address entry in our dictionary
         config.update({'address' : addr})
 
-        # now call the regular function from within our base class
+        # call base class
         super().update(config)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/macsec.py b/python/vyos/ifconfig/macsec.py
index ea8c9807e..6f570d162 100644
--- a/python/vyos/ifconfig/macsec.py
+++ b/python/vyos/ifconfig/macsec.py
@@ -71,3 +71,22 @@ class MACsecIf(Interface):
             'source_interface': '',
         }
         return config
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig/macvlan.py b/python/vyos/ifconfig/macvlan.py
index b5481f4a7..b068ce873 100644
--- a/python/vyos/ifconfig/macvlan.py
+++ b/python/vyos/ifconfig/macvlan.py
@@ -68,3 +68,22 @@ class MACVLANIf(Interface):
         >> dict = MACVLANIf().get_config()
         """
         return deepcopy(cls.default)
+
+    def update(self, config):
+        """ General helper function which works on a dictionary retrived by
+        get_config_dict(). It's main intention is to consolidate the scattered
+        interface setup code and provide a single point of entry when workin
+        on any interface. """
+
+        # call base class first
+        super().update(config)
+
+        # Enable/Disable of an interface must always be done at the end of the
+        # derived class to make use of the ref-counting set_admin_state()
+        # function. We will only enable the interface if 'up' was called as
+        # often as 'down'. This is required by some interface implementations
+        # as certain parameters can only be changed when the interface is
+        # in admin-down state. This ensures the link does not flap during
+        # reconfiguration.
+        state = 'down' if 'disable' in config else 'up'
+        self.set_admin_state(state)
diff --git a/python/vyos/ifconfig_vlan.py b/python/vyos/ifconfig_vlan.py
deleted file mode 100644
index 442cb0db8..000000000
--- a/python/vyos/ifconfig_vlan.py
+++ /dev/null
@@ -1,245 +0,0 @@
-# Copyright 2019-2020 VyOS maintainers and contributors <maintainers@vyos.io>
-#
-# This library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Lesser General Public
-# License as published by the Free Software Foundation; either
-# version 2.1 of the License, or (at your option) any later version.
-#
-# This library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# Lesser General Public License for more details.
-#
-# You should have received a copy of the GNU Lesser General Public
-# License along with this library.  If not, see <http://www.gnu.org/licenses/>.
-
-from netifaces import interfaces
-from vyos import ConfigError
-
-def apply_all_vlans(intf, intfconfig):
-    """
-    Function applies all VLANs to the passed interface.
-
-    intf: object of Interface class
-    intfconfig: dict with interface configuration
-    """
-    # remove no longer required service VLAN interfaces (vif-s)
-    for vif_s in intfconfig['vif_s_remove']:
-        intf.del_vlan(vif_s)
-
-    # create service VLAN interfaces (vif-s)
-    for vif_s_id, vif_s in intfconfig['vif_s'].items():
-        s_vlan = intf.add_vlan(vif_s_id, ethertype=vif_s['ethertype'])
-        apply_vlan_config(s_vlan, vif_s)
-
-        # remove no longer required client VLAN interfaces (vif-c)
-        # on lower service VLAN interface
-        for vif_c in vif_s['vif_c_remove']:
-            s_vlan.del_vlan(vif_c)
-
-        # create client VLAN interfaces (vif-c)
-        # on lower service VLAN interface
-        for vif_c_id, vif_c in vif_s['vif_c'].items():
-            c_vlan = s_vlan.add_vlan(vif_c_id)
-            apply_vlan_config(c_vlan, vif_c)
-
-    # remove no longer required VLAN interfaces (vif)
-    for vif in intfconfig['vif_remove']:
-        intf.del_vlan(vif)
-
-    # create VLAN interfaces (vif)
-    for vif_id, vif in intfconfig['vif'].items():
-        # QoS priority mapping can only be set during interface creation
-        # so we delete the interface first if required.
-        if vif['egress_qos_changed'] or vif['ingress_qos_changed']:
-            try:
-                # on system bootup the above condition is true but the interface
-                # does not exists, which throws an exception, but that's legal
-                intf.del_vlan(vif_id)
-            except:
-                pass
-
-        vlan = intf.add_vlan(vif_id, ingress_qos=vif['ingress_qos'], egress_qos=vif['egress_qos'])
-        apply_vlan_config(vlan, vif)
-
-
-def apply_vlan_config(vlan, config):
-    """
-    Generic function to apply a VLAN configuration from a dictionary
-    to a VLAN interface
-    """
-
-    if not vlan.definition['vlan']:
-        raise TypeError()
-
-    if config['dhcp_client_id']:
-        vlan.dhcp.v4.options['client_id'] = config['dhcp_client_id']
-
-    if config['dhcp_hostname']:
-        vlan.dhcp.v4.options['hostname'] = config['dhcp_hostname']
-
-    if config['dhcp_vendor_class_id']:
-        vlan.dhcp.v4.options['vendor_class_id'] = config['dhcp_vendor_class_id']
-
-    if config['dhcpv6_prm_only']:
-        vlan.dhcp.v6.options['dhcpv6_prm_only'] = True
-
-    if config['dhcpv6_temporary']:
-        vlan.dhcp.v6.options['dhcpv6_temporary'] = True
-
-    if config['dhcpv6_pd_length']:
-        vlan.dhcp.v6.options['dhcpv6_pd_length'] = config['dhcpv6_pd_length']
-
-    if config['dhcpv6_pd_interfaces']:
-        vlan.dhcp.v6.options['dhcpv6_pd_interfaces'] = config['dhcpv6_pd_interfaces']
-
-    # update interface description used e.g. within SNMP
-    vlan.set_alias(config['description'])
-    # ignore link state changes
-    vlan.set_link_detect(config['disable_link_detect'])
-    # configure ARP filter configuration
-    vlan.set_arp_filter(config['ip_disable_arp_filter'])
-    # configure ARP accept
-    vlan.set_arp_accept(config['ip_enable_arp_accept'])
-    # configure ARP announce
-    vlan.set_arp_announce(config['ip_enable_arp_announce'])
-    # configure ARP ignore
-    vlan.set_arp_ignore(config['ip_enable_arp_ignore'])
-    # configure Proxy ARP
-    vlan.set_proxy_arp(config['ip_proxy_arp'])
-    # IPv6 accept RA
-    vlan.set_ipv6_accept_ra(config['ipv6_accept_ra'])
-    # IPv6 address autoconfiguration
-    vlan.set_ipv6_autoconf(config['ipv6_autoconf'])
-    # IPv6 forwarding
-    vlan.set_ipv6_forwarding(config['ipv6_forwarding'])
-    # IPv6 Duplicate Address Detection (DAD) tries
-    vlan.set_ipv6_dad_messages(config['ipv6_dup_addr_detect'])
-    # Maximum Transmission Unit (MTU)
-    vlan.set_mtu(config['mtu'])
-
-    # assign/remove VRF (ONLY when not a member of a bridge,
-    # otherwise 'nomaster' removes it from it)
-    if not config['is_bridge_member']:
-        vlan.set_vrf(config['vrf'])
-
-    # Delete old IPv6 EUI64 addresses before changing MAC
-    for addr in config['ipv6_eui64_prefix_remove']:
-        vlan.del_ipv6_eui64_address(addr)
-
-    # Change VLAN interface MAC address
-    if config['mac']:
-        vlan.set_mac(config['mac'])
-
-    # Add IPv6 EUI-based addresses
-    for addr in config['ipv6_eui64_prefix']:
-        vlan.add_ipv6_eui64_address(addr)
-
-    # enable/disable VLAN interface
-    if config['disable']:
-        vlan.set_admin_state('down')
-    else:
-        vlan.set_admin_state('up')
-
-    # Configure interface address(es)
-    # - not longer required addresses get removed first
-    # - newly addresses will be added second
-    for addr in config['address_remove']:
-        vlan.del_addr(addr)
-    for addr in config['address']:
-        vlan.add_addr(addr)
-
-    # re-add ourselves to any bridge we might have fallen out of
-    if config['is_bridge_member']:
-        vlan.add_to_bridge(config['is_bridge_member'])
-
-def verify_vlan_config(config):
-    """
-    Generic function to verify VLAN config consistency. Instead of re-
-    implementing this function in multiple places use single source \o/
-    """
-
-    # config['vif'] is a dict with ids as keys and config dicts as values
-    for vif in config['vif'].values():
-        # DHCPv6 parameters-only and temporary address are mutually exclusive
-        if vif['dhcpv6_prm_only'] and vif['dhcpv6_temporary']:
-            raise ConfigError('DHCPv6 temporary and parameters-only options are mutually exclusive!')
-
-        if ( vif['is_bridge_member']
-                and ( vif['address']
-                    or vif['ipv6_eui64_prefix']
-                    or vif['ipv6_autoconf'] ) ):
-            raise ConfigError((
-                    f'Cannot assign address to vif interface {vif["intf"]} '
-                    f'which is a member of bridge {vif["is_bridge_member"]}'))
-
-        if vif['vrf']:
-            if vif['vrf'] not in interfaces():
-                raise ConfigError(f'VRF "{vif["vrf"]}" does not exist')
-
-            if vif['is_bridge_member']:
-                raise ConfigError((
-                    f'vif {vif["intf"]} cannot be member of VRF {vif["vrf"]} '
-                    f'and bridge {vif["is_bridge_member"]} at the same time!'))
-
-    # e.g. wireless interface has no vif_s support
-    # thus we bail out eraly.
-    if 'vif_s' not in config.keys():
-        return
-
-    # config['vif_s'] is a dict with ids as keys and config dicts as values
-    for vif_s_id, vif_s in config['vif_s'].items():
-        for vif_id, vif in config['vif'].items():
-            if vif_id == vif_s_id:
-                raise ConfigError((
-                    f'Cannot use identical ID on vif "{vif["intf"]}" '
-                    f'and vif-s "{vif_s["intf"]}"'))
-
-        # DHCPv6 parameters-only and temporary address are mutually exclusive
-        if vif_s['dhcpv6_prm_only'] and vif_s['dhcpv6_temporary']:
-            raise ConfigError((
-                'DHCPv6 temporary and parameters-only options are mutually '
-                'exclusive!'))
-
-        if ( vif_s['is_bridge_member']
-                and ( vif_s['address']
-                    or vif_s['ipv6_eui64_prefix']
-                    or vif_s['ipv6_autoconf'] ) ):
-            raise ConfigError((
-                    f'Cannot assign address to vif-s interface {vif_s["intf"]} '
-                    f'which is a member of bridge {vif_s["is_bridge_member"]}'))
-
-        if vif_s['vrf']:
-            if vif_s['vrf'] not in interfaces():
-                raise ConfigError(f'VRF "{vif_s["vrf"]}" does not exist')
-
-            if vif_s['is_bridge_member']:
-                raise ConfigError((
-                    f'vif-s {vif_s["intf"]} cannot be member of VRF {vif_s["vrf"]} '
-                    f'and bridge {vif_s["is_bridge_member"]} at the same time!'))
-
-        # vif_c is a dict with ids as keys and config dicts as values
-        for vif_c in vif_s['vif_c'].values():
-            # DHCPv6 parameters-only and temporary address are mutually exclusive
-            if vif_c['dhcpv6_prm_only'] and vif_c['dhcpv6_temporary']:
-                raise ConfigError((
-                    'DHCPv6 temporary and parameters-only options are '
-                    'mutually exclusive!'))
-
-            if ( vif_c['is_bridge_member']
-                    and ( vif_c['address']
-                        or vif_c['ipv6_eui64_prefix']
-                        or vif_c['ipv6_autoconf'] ) ):
-                raise ConfigError((
-                    f'Cannot assign address to vif-c interface {vif_c["intf"]} '
-                    f'which is a member of bridge {vif_c["is_bridge_member"]}'))
-
-            if vif_c['vrf']:
-                if vif_c['vrf'] not in interfaces():
-                    raise ConfigError(f'VRF "{vif_c["vrf"]}" does not exist')
-
-                if vif_c['is_bridge_member']:
-                    raise ConfigError((
-                    f'vif-c {vif_c["intf"]} cannot be member of VRF {vif_c["vrf"]} '
-                    f'and bridge {vif_c["is_bridge_member"]} at the same time!'))
-
diff --git a/python/vyos/util.py b/python/vyos/util.py
index 7234be6cb..7078762df 100644
--- a/python/vyos/util.py
+++ b/python/vyos/util.py
@@ -242,7 +242,7 @@ def chown(path, user, group):
 
     if not os.path.exists(path):
         return False
-	
+
     uid = getpwnam(user).pw_uid
     gid = getgrnam(group).gr_gid
     os.chown(path, uid, gid)
diff --git a/python/vyos/validate.py b/python/vyos/validate.py
index a0620e4dd..ceeb6888a 100644
--- a/python/vyos/validate.py
+++ b/python/vyos/validate.py
@@ -279,7 +279,6 @@ def is_member(conf, interface, intftype=None):
     False -> interface type cannot have members
     """
     ret_val = None
-
     if intftype not in ['bonding', 'bridge', None]:
         raise ValueError((
             f'unknown interface type "{intftype}" or it cannot '
@@ -292,9 +291,9 @@ def is_member(conf, interface, intftype=None):
     conf.set_level([])
 
     for it in intftype:
-        base = 'interfaces ' + it
+        base = ['interfaces', it]
         for intf in conf.list_nodes(base):
-            memberintf = [base, intf, 'member', 'interface']
+            memberintf = base + [intf, 'member', 'interface']
             if xml.is_tag(memberintf):
                 if interface in conf.list_nodes(memberintf):
                     ret_val = intf