Merge pull request #5019 from natali-rs1985/T8324

vpp: T8324: Migrate loopback interface to 'interfaces vpp loopback'

11 files changed, 202 insertions, 247 deletions

diff --git a/interface-definitions/vpp.xml.in b/interface-definitions/vpp.xml.in
index ca9838af0..733e8eb83 100644
--- a/interface-definitions/vpp.xml.in
+++ b/interface-definitions/vpp.xml.in
@@ -146,25 +146,6 @@
               #include <include/kernel-interface-tun.xml.i>
             </children>
           </tagNode>
-          <tagNode name="loopback" owner="${vyos_conf_scripts_dir}/vpp_interfaces_loopback.py">
-            <properties>
-              <priority>325</priority>
-              <help>Loopback Interface</help>
-              <constraint>
-                <regex>lo[0-9]+</regex>
-              </constraint>
-              <constraintErrorMessage>Loopback interface must be named loN</constraintErrorMessage>
-              <valueHelp>
-                <format>loN</format>
-                <description>Loopback interface name</description>
-              </valueHelp>
-            </properties>
-            <children>
-              #include <include/generic-description.xml.i>
-              #include <include/interface/disable.xml.i>
-              #include <include/kernel-interface-tun.xml.i>
-            </children>
-          </tagNode>
           <tagNode name="xconnect" owner="${vyos_conf_scripts_dir}/vpp_interfaces_xconnect.py">
             <properties>
               <help>Layer 2 cross connect</help>
diff --git a/interface-definitions/vpp_interface_loopback.xml.in b/interface-definitions/vpp_interface_loopback.xml.in
new file mode 100644
index 000000000..9998c34d2
--- /dev/null
+++ b/interface-definitions/vpp_interface_loopback.xml.in
@@ -0,0 +1,32 @@
+<?xml version="1.0"?>
+<interfaceDefinition>
+  <node name='interfaces'>
+    <children>
+      <node name='vpp'>
+        <children>
+          <tagNode name="loopback" owner="${vyos_conf_scripts_dir}/vpp_interfaces_loopback.py">
+            <properties>
+              <priority>325</priority>
+              <help>Loopback Interface</help>
+              <constraint>
+                <regex>vpplo[0-9]+</regex>
+              </constraint>
+              <constraintErrorMessage>Loopback interface must be named vpploN</constraintErrorMessage>
+              <valueHelp>
+                <format>vpploN</format>
+                <description>Loopback interface name</description>
+              </valueHelp>
+            </properties>
+            <children>
+              #include <include/generic-description.xml.i>
+              #include <include/interface/disable.xml.i>
+              #include <include/interface/address-ipv4-ipv6.xml.i>
+              #include <include/interface/mtu-68-16000.xml.i>
+              #include <include/vpp/vif.xml.i>
+            </children>
+          </tagNode>
+        </children>
+      </node>
+    </children>
+  </node>
+</interfaceDefinition>
diff --git a/python/vyos/ifconfig/vpp/__init__.py b/python/vyos/ifconfig/vpp/__init__.py
index a7cfe79a4..b0a477c28 100644
--- a/python/vyos/ifconfig/vpp/__init__.py
+++ b/python/vyos/ifconfig/vpp/__init__.py
@@ -18,11 +18,13 @@
 from .bond import VPPBondInterface
 from .interface import VPPInterface
 from .ipip import VPPIPIPInterface
+from .loopback import VPPLoopbackInterface
 from .vxlan import VPPVXLANInterface
 
 __all__ = [
     'VPPBondInterface',
     'VPPInterface',
     'VPPIPIPInterface',
+    'VPPLoopbackInterface',
     'VPPVXLANInterface',
 ]
diff --git a/python/vyos/ifconfig/vpp/loopback.py b/python/vyos/ifconfig/vpp/loopback.py
new file mode 100644
index 000000000..36a30cb58
--- /dev/null
+++ b/python/vyos/ifconfig/vpp/loopback.py
@@ -0,0 +1,105 @@
+# VyOS implementation of VPP Loopback interface
+#
+# Copyright (C) VyOS Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+from vyos.ifconfig import Interface
+from vyos.ifconfig.vpp.interface import VPPInterface
+
+
+class VPPLoopbackInterface(Interface, VPPInterface):
+    """Interface Loopback"""
+
+    def __init__(self, ifname, config):
+        self.ifname = ifname
+        self.instance = int(ifname.removeprefix('vpplo'))
+        self.vpp_ifname = f'loop{self.instance}'
+
+        # Initialize Interface (kernel) and VPP part
+        super().__init__(ifname)
+        VPPInterface.__init__(self, self.vpp_ifname)
+
+        self.index = self.vpp.get_sw_if_index(self.vpp_ifname)
+        self.state = 'up' if 'disable' not in config else 'down'
+
+    def _create(self):
+        pass
+
+    def add(self):
+        """Create Loopback interface
+        https://github.com/FDio/vpp/blob/stable/2306/src/vnet/interface.api
+        Example:
+            from vyos.ifconfig.vpp import VPPLoopbackInterface
+            a = VPPLoopbackInterface(ifname='vpplo1', config)
+            a.add()
+        """
+        self.vpp.api.create_loopback_instance(
+            is_specified=True, user_instance=self.instance
+        )
+        # Add LCP pair (kernel) interface
+        self.kernel_add()
+        # Set interface state
+        self.set_state(self.state)
+        self.set_admin_state(self.state)
+        self.index = self.vpp.get_sw_if_index(self.vpp_ifname)
+
+    def delete(self):
+        """Delete Loopback interface
+        Example:
+            from vyos.ifconfig.vpp import VPPLoopbackInterface
+            a = VPPLoopbackInterface(ifname='vpplo1', config)
+            a.delete()
+        """
+        return self.vpp.api.delete_loopback(sw_if_index=self.index)
+
+    def kernel_add(self):
+        """Add LCP pair
+        Example:
+            from vyos.ifconfig.vpp import VPPLoopbackInterface
+            a = VPPLoopbackInterface(ifname='vpplo1')
+            a.kernel_add()
+        """
+        self.vpp.lcp_pair_add(self.vpp_ifname, self.ifname)
+
+    def kernel_delete(self):
+        """Delete LCP pair
+        Example:
+            from vyos.ifconfig.vpp import VPPLoopbackInterface
+            a = VPPLoopbackInterface(ifname='vpplo1')
+            a.kernel_delete()
+        """
+        self.vpp.lcp_pair_del(self.vpp_ifname, self.ifname)
+
+    def remove(self):
+        if self.index:
+            # Delete lcp pair interface
+            if self.vpp.lcp_pair_find(vpp_name_hw=self.vpp_ifname):
+                self.kernel_delete()
+
+            # Delete loopback interface
+            self.delete()
+
+    def update(self, config):
+        # Add loopback interface
+        self.add()
+
+        # Set rx-mode
+        rx_mode = config.get('vpp_settings', {}).get('interface_rx_mode')
+        if rx_mode:
+            self.set_rx_mode(rx_mode)
+
+        # Apply all settings to the lcp pair (kernel) interface
+        super().update(config)
diff --git a/python/vyos/vpp/interface/__init__.py b/python/vyos/vpp/interface/__init__.py
index f970edb63..4ae96f486 100644
--- a/python/vyos/vpp/interface/__init__.py
+++ b/python/vyos/vpp/interface/__init__.py
@@ -20,7 +20,6 @@ from .ethernet import EthernetInterface
 from .geneve import GeneveInterface
 from .gre import GREInterface
 from .interface import Interface
-from .loopback import LoopbackInterface
 from .wireguard import WireguardInterface
 from .xconnect import XconnectInterface
 
@@ -30,7 +29,6 @@ __all__ = [
     'GeneveInterface',
     'GREInterface',
     'Interface',
-    'LoopbackInterface',
     'WireguardInterface',
     'XconnectInterface',
 ]
diff --git a/python/vyos/vpp/interface/loopback.py b/python/vyos/vpp/interface/loopback.py
deleted file mode 100644
index 357423780..000000000
--- a/python/vyos/vpp/interface/loopback.py
+++ /dev/null
@@ -1,72 +0,0 @@
-# VyOS implementation of VPP Loopback interface
-#
-# Copyright (C) VyOS Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program 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 General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
-from vyos.vpp.interface.interface import Interface
-
-
-class LoopbackInterface(Interface):
-    """Interface Loopback"""
-
-    def __init__(self, ifname, kernel_interface: str = '', state: str = 'up'):
-        super().__init__(ifname)
-        self.instance = int(ifname.removeprefix('lo'))
-        self.ifname = f'loop{self.instance}'
-        self.kernel_interface = kernel_interface
-        self.initial_state = state
-
-    def add(self):
-        """Create Loopback interface
-        https://github.com/FDio/vpp/blob/stable/2306/src/vnet/interface.api
-        Example:
-            from vyos.vpp.interface import LoopbackInterface
-            a = LoopbackInterface(ifname='lo1')
-            a.add()
-        """
-        self.vpp.api.create_loopback_instance(
-            is_specified=True, user_instance=self.instance
-        )
-        # Set interface state
-        self.set_state(self.initial_state)
-
-    def delete(self):
-        """Delete Loopback interface
-        Example:
-            from vyos.vpp.interface import LoopbackInterface
-            a = LoopbackInterface(ifname='lo1')
-            a.delete()
-        """
-        loopback_if_index = self.vpp.get_sw_if_index(f'loop{self.instance}')
-        return self.vpp.api.delete_loopback(sw_if_index=loopback_if_index)
-
-    def kernel_add(self):
-        """Add LCP pair
-        Example:
-            from vyos.vpp.interface import LoopbackInterface
-            a = LoopbackInterface(ifname='lo1')
-            a.kernel_add()
-        """
-        self.vpp.lcp_pair_add(self.ifname, self.kernel_interface)
-
-    def kernel_delete(self):
-        """Delete LCP pair
-        Example:
-            from vyos.vpp.interface import LoopbackInterface
-            a = LoopbackInterface(ifname='lo1')
-            a.kernel_delete()
-        """
-        self.vpp.lcp_pair_del(self.ifname, self.kernel_interface)
diff --git a/smoketest/configs/assert/vpp b/smoketest/configs/assert/vpp
index 8a68852b7..f8cab98f4 100644
--- a/smoketest/configs/assert/vpp
+++ b/smoketest/configs/assert/vpp
@@ -38,7 +38,7 @@ set vpp interfaces gre gre12 source-address '192.0.2.21'
 set vpp interfaces gre gre12 tunnel-type 'l3'
 set interfaces vpp ipip vppipip20 remote '192.0.2.2'
 set interfaces vpp ipip vppipip20 source-address '192.0.2.1'
-set vpp interfaces loopback lo12 description 'Loop12'
+set interfaces vpp loopback vpplo12 description 'Loop12'
 set interfaces vpp vxlan vppvxlan10 remote '192.0.2.2'
 set interfaces vpp vxlan vppvxlan10 source-address '192.0.2.1'
 set interfaces vpp vxlan vppvxlan10 vni '10'
diff --git a/smoketest/scripts/cli/test_vpp.py b/smoketest/scripts/cli/test_vpp.py
index 20baed178..90e4e4538 100755
--- a/smoketest/scripts/cli/test_vpp.py
+++ b/smoketest/scripts/cli/test_vpp.py
@@ -517,84 +517,28 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         self.cli_commit()
 
     def test_05_vpp_loopback(self):
-        interface_loopback = 'lo11'
-        interface_kernel = 'vpptun11'
-        new_interface_kernel = 'vpptun12'
-        kernel_address = '192.0.2.54'
+        loopback_path = interfaces_path + ['loopback']
+        interface_loopback = 'vpplo11'
+        address = '192.0.2.54'
 
-        self.cli_set(base_path + ['interfaces', 'loopback', interface_loopback])
-        self.cli_set(
-            base_path
-            + [
-                'interfaces',
-                'loopback',
-                interface_loopback,
-                'kernel-interface',
-                interface_kernel,
-            ]
-        )
-        self.cli_set(
-            base_path
-            + ['kernel-interfaces', interface_kernel, 'address', f'{kernel_address}/25']
-        )
+        self.cli_set(loopback_path + [interface_loopback])
+        self.cli_set(loopback_path + [interface_loopback, 'address', f'{address}/25'])
 
         # commit changes
         self.cli_commit()
 
-        self.assertTrue(os.path.isdir(f'/sys/class/net/{interface_kernel}'))
+        self.assertTrue(os.path.isdir(f'/sys/class/net/{interface_loopback}'))
 
-        current_address = get_address(interface_kernel)
-        self.assertEqual(kernel_address, current_address)
+        current_address = get_address(interface_loopback)
+        self.assertEqual(address, current_address)
 
         # check loopback interface
         _, out = rc_cmd('sudo vppctl show interface loop11')
         required_str = 'loop11'
         self.assertIn(required_str, out)
 
-        # delete loopback kernel-interface but do not delete 'vpp kernel-interface'
-        # expect raise ConfigError
-        self.cli_delete(
-            base_path
-            + [
-                'interfaces',
-                'loopback',
-                interface_loopback,
-                'kernel-interface',
-                interface_kernel,
-            ]
-        )
-        with self.assertRaises(ConfigSessionError):
-            self.cli_commit()
-
-        # update loopback kernel-interface but do not change 'vpp kernel-interface'
-        # expect raise ConfigError
-        self.cli_set(
-            base_path
-            + [
-                'interfaces',
-                'loopback',
-                interface_loopback,
-                'kernel-interface',
-                new_interface_kernel,
-            ]
-        )
-        with self.assertRaises(ConfigSessionError):
-            self.cli_commit()
-
-        # delete vpp kernel-interface
-        self.cli_delete(base_path + ['kernel-interfaces', interface_kernel])
-        self.cli_commit()
-
-        # delete loopback kernel-interface
-        self.cli_delete(
-            base_path
-            + ['interfaces', 'loopback', interface_loopback, 'kernel-interface']
-        )
-        self.cli_commit()
-        self.assertFalse(os.path.isdir(f'/sys/class/net/{interface_kernel}'))
-
         # delete loopback interface
-        self.cli_delete(base_path + ['interfaces', 'loopback', interface_loopback])
+        self.cli_delete(loopback_path + [interface_loopback])
         self.cli_commit()
 
     def test_06_vpp_bonding(self):
@@ -801,7 +745,7 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         self.assertRegex(out, r'\s*vxlan_tunnel23\s+\d+\s+\d+')
 
         # Add Loopback BVI to the bridge
-        self.cli_set(base_path + ['interfaces', 'loopback', f'lo{vni}'])
+        self.cli_set(interfaces_path + ['loopback', f'vpplo{vni}'])
         self.cli_set(
             base_path
             + [
@@ -810,7 +754,7 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
                 interface_bridge,
                 'member',
                 'interface',
-                f'lo{vni}',
+                f'vpplo{vni}',
                 'bvi',
             ]
         )
diff --git a/src/conf_mode/vpp_interfaces_bridge.py b/src/conf_mode/vpp_interfaces_bridge.py
index 8d25cba00..d53173f04 100644
--- a/src/conf_mode/vpp_interfaces_bridge.py
+++ b/src/conf_mode/vpp_interfaces_bridge.py
@@ -96,7 +96,7 @@ def verify(config):
 
     # Check if interface exists in vpp before adding to bridge-domain
 
-    allowed_prefixes = ('vppbond', 'gre', 'geneve', 'lo', 'vppvxlan')
+    allowed_prefixes = ('vppbond', 'gre', 'geneve', 'vpplo', 'vppvxlan')
 
     if 'member' in config:
         bvi_exists = False
@@ -116,7 +116,7 @@ def verify(config):
             if 'bvi' in member_config:
                 if bvi_exists:
                     raise ConfigError("Only one BVI per bridge domain is allowed")
-                if not member.startswith('lo'):
+                if not member.startswith('vpplo'):
                     raise ConfigError("BVI can only be defined on loopback interface")
                 bvi_exists = True
 
@@ -138,9 +138,9 @@ def apply(config):
         for member in config.get('members_removed'):
             if member.startswith(interface_transform_filter):
                 member = iftunnel_transform(member)
-            if member.startswith('lo'):
+            if member.startswith('vpplo'):
                 # interface name in VPP is loopX
-                member = member.replace('lo', 'loop')
+                member = member.replace('vpplo', 'loop')
             elif member.startswith('vppbond'):
                 # interface name in VPP is BondEthernetX
                 member = member.replace('vppbond', 'BondEthernet')
@@ -166,9 +166,9 @@ def apply(config):
         for member, member_config in members.items():
             if member.startswith(interface_transform_filter):
                 member = iftunnel_transform(member)
-            if member.startswith('lo'):
+            if member.startswith('vpplo'):
                 # interface name in VPP is loopX
-                member = member.replace('lo', 'loop')
+                member = member.replace('vpplo', 'loop')
                 if 'bvi' in member_config:
                     port_type = 1
             elif member.startswith('vppbond'):
diff --git a/src/conf_mode/vpp_interfaces_loopback.py b/src/conf_mode/vpp_interfaces_loopback.py
index d08557959..2f7b59354 100644
--- a/src/conf_mode/vpp_interfaces_loopback.py
+++ b/src/conf_mode/vpp_interfaces_loopback.py
@@ -16,22 +16,14 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-import os
-
 from vyos import ConfigError
 
 from vyos.config import Config
-from vyos.configdict import leaf_node_changed
+from vyos.configdict import get_interface_dict
 from vyos.configdep import set_dependents, call_dependents
-from vyos.template import is_interface
+from vyos.utils.process import is_systemd_service_active
 
-from vyos.vpp.interface import LoopbackInterface
-from vyos.vpp.config_verify import (
-    verify_vpp_remove_kernel_interface,
-    verify_vpp_change_kernel_interface,
-    verify_vpp_exists_kernel_interface,
-)
-from vyos.vpp.utils import cli_ifaces_lcp_kernel_list
+from vyos.ifconfig.vpp import VPPLoopbackInterface
 
 
 def get_config(config=None) -> dict:
@@ -47,62 +39,22 @@ def get_config(config=None) -> dict:
     else:
         conf = Config()
 
-    base = ['vpp', 'interfaces', 'loopback']
-    base_kernel_interfaces = ['vpp', 'kernel-interfaces']
-
-    ifname = os.environ['VYOS_TAGNODE_VALUE']
+    base = ['interfaces', 'vpp', 'loopback']
 
-    # Get config_dict with default values
-    config = conf.get_config_dict(
-        base + [ifname],
-        key_mangling=('-', '_'),
-        get_first_key=True,
-        no_tag_node_value_mangle=True,
-        with_defaults=True,
-        with_recursive_defaults=True,
-    )
+    ifname, config = get_interface_dict(conf, base)
 
-    if not conf.exists(['vpp']):
+    if not conf.exists(['vpp']) and not conf.exists(base):
         config['remove_vpp'] = True
         return config
 
-    # Get effective config as we need full dicitonary per interface delete
-    effective_config = conf.get_config_dict(
-        base + [ifname],
+    # Get 'vpp settings' config
+    config['vpp_settings'] = conf.get_config_dict(
+        ['vpp', 'settings'],
         key_mangling=('-', '_'),
-        effective=True,
         get_first_key=True,
         no_tag_node_value_mangle=True,
     )
 
-    if effective_config:
-        config.update({'effective': effective_config})
-
-    if not conf.exists(base + [ifname]):
-        config['remove'] = True
-
-    # Get global 'vpp kernel-interfaces' for verify
-    config['vpp_kernel_interfaces'] = conf.get_config_dict(
-        base_kernel_interfaces,
-        key_mangling=('-', '_'),
-        get_first_key=True,
-        no_tag_node_value_mangle=True,
-    )
-
-    tmp = leaf_node_changed(conf, base + [ifname, 'kernel-interface'])
-    if tmp:
-        config['kernel_interface_removed'] = tmp
-
-    # list of all kernel interfaces `vpp interface xxx kernel-interface xxx`
-    config['candidate_kernel_interfaces'] = cli_ifaces_lcp_kernel_list(conf)
-
-    # Dependency
-    if effective_config.get('kernel_interface'):
-        if conf.exists(base + [ifname, 'kernel-interface']):
-            iface = config.get('kernel_interface')
-            if conf.exists(['vpp', 'kernel-interfaces', iface]):
-                set_dependents('vpp_kernel_interface', conf, iface)
-
     # NAT dependency
     if conf.exists(['vpp', 'nat', 'nat44']):
         set_dependents('vpp_nat_nat44', conf)
@@ -113,7 +65,6 @@ def get_config(config=None) -> dict:
     if conf.exists(['vpp', 'acl']):
         set_dependents('vpp_acl', conf)
 
-    config['ifname'] = ifname
     return config
 
 
@@ -122,13 +73,10 @@ def verify(config):
     if 'remove_vpp' in config:
         return None
 
-    verify_vpp_remove_kernel_interface(config)
-
-    if 'remove' in config:
-        return None
-
-    verify_vpp_change_kernel_interface(config)
-    verify_vpp_exists_kernel_interface(config)
+    if not is_systemd_service_active('vpp.service'):
+        raise ConfigError(
+            'Cannot configure VPP loopback interface: vpp.service is not running'
+        )
 
 
 def generate(config):
@@ -140,23 +88,13 @@ def apply(config):
         return None
 
     ifname = config.get('ifname')
-    # Delete interface
-    if 'effective' in config:
-        i = LoopbackInterface(ifname)
-        i.delete()
-
-    if 'remove' in config:
-        return None
+    loopback = VPPLoopbackInterface(ifname, config)
+    loopback.remove()
 
-    # Add interface
-    kernel_interface = config.get('kernel_interface', '')
-    state = 'up' if 'disable' not in config else 'down'
-    i = LoopbackInterface(ifname, kernel_interface, state)
-    i.add()
+    if 'deleted' in config:
+        return
 
-    # Add kernel-interface (LCP) if interface is not exist
-    if 'kernel_interface' in config and not is_interface(kernel_interface):
-        i.kernel_add()
+    loopback.update(config)
 
     call_dependents()
 
diff --git a/src/migration-scripts/vpp/5-to-6 b/src/migration-scripts/vpp/5-to-6
index 18f0f70d2..23b2d4eaa 100644
--- a/src/migration-scripts/vpp/5-to-6
+++ b/src/migration-scripts/vpp/5-to-6
@@ -43,6 +43,8 @@
 #
 # Move ipip interface from vpp section to 'interfaces vpp ipip' (T8314)
 #
+# Migrate loopback interface from vpp section to 'interfaces vpp loopback' (T8324)
+#
 
 from vyos.configtree import ConfigTree
 
@@ -437,6 +439,30 @@ def _migrate_vpp_ipip_interface(config: ConfigTree) -> None:
         config.delete(['vpp', 'interfaces'])
 
 
+def _migrate_vpp_loopback_interface(config: ConfigTree) -> None:
+    base = ['vpp', 'interfaces', 'loopback']
+    new_base = ['interfaces', 'vpp', 'loopback']
+    kernel_interface_base = ['vpp', 'kernel-interfaces']
+
+    if not config.exists(base):
+        return
+
+    config.set(new_base)
+
+    for ifname in config.list_nodes(base):
+        _migrate_interface(config, 'loopback', ifname)
+
+        _migrate_members_bridge(config, ifname)
+
+    config.delete(base)
+
+    if config.exists(kernel_interface_base) and len(config.list_nodes(kernel_interface_base)) == 0:
+        config.delete(['vpp', 'kernel-interfaces'])
+
+    if len(config.list_nodes(['vpp', 'interfaces'])) == 0:
+        config.delete(['vpp', 'interfaces'])
+
+
 def migrate(config: ConfigTree) -> None:
     if not config.exists(['vpp']):
         # Nothing to do
@@ -455,3 +481,4 @@ def migrate(config: ConfigTree) -> None:
     _migrate_vpp_bonding_interface(config)
     _migrate_vpp_vxlan_interface(config)
     _migrate_vpp_ipip_interface(config)
+    _migrate_vpp_loopback_interface(config)