vpp: T8438: Add bidirectional interface-in-use validation

Add bidirectional VPP interface reference validation: prevent assigning an interface used by a VPP feature (NAT/ACL/IPFIX/sFlow, etc.)
as a VPP member (bond/bridge/xconnect) and prevent using a VPP member interface in VPP features.
Block interface deletion when it is still referenced by any VPP feature/member.
Fix VLAN subinterface removal checks broken by the recent VPP config tree restructuring.

12 files changed, 235 insertions, 101 deletions

diff --git a/python/vyos/vpp/config_verify.py b/python/vyos/vpp/config_verify.py
index b32544a40..da8e3d24b 100644
--- a/python/vyos/vpp/config_verify.py
+++ b/python/vyos/vpp/config_verify.py
@@ -21,11 +21,127 @@ import psutil
 from vyos import ConfigError
 from vyos.base import Warning
 from vyos.utils.cpu import get_core_count as total_core_count, get_cpus
+from vyos.utils.dict import dict_search
 
 from vyos.vpp.config_resource_checks import memory as mem_checks
 from vyos.vpp.config_resource_checks.resource_defaults import default_resource_map
 from vyos.vpp.utils import human_memory_to_bytes, bytes_to_human_memory
 
+# VPP feature paths that reference interfaces
+_VPP_FEATURE_INTERFACE_REFS = [
+    ('nat.cgnat.interface.inside', None, 'VPP CGNAT inside'),
+    ('nat.cgnat.interface.outside', None, 'VPP CGNAT outside'),
+    ('nat.nat44.interface.inside', None, 'VPP NAT44 inside'),
+    ('nat.nat44.interface.outside', None, 'VPP NAT44 outside'),
+    (
+        'nat.nat44.address_pool.translation.interface',
+        None,
+        'VPP NAT44 translation pool',
+    ),
+    ('nat.nat44.address_pool.twice_nat.interface', None, 'VPP NAT44 twice-NAT pool'),
+    ('nat.nat44.exclude.rule', 'external_interface', 'VPP NAT44 exclude rule external'),
+    ('acl.ip.interface', None, 'VPP IP ACL'),
+    ('acl.mac.interface', None, 'VPP MAC ACL'),
+    ('ipfix.interface', None, 'IPFIX monitoring'),
+    ('sflow.interface', None, 'VPP sFlow'),
+]
+# VPP member configuration paths that reference interfaces
+_VPP_MEMBER_INTERFACE_REFS = [
+    ('interfaces_vpp.bonding', 'member.interface', 'VPP bonding member'),
+    ('interfaces_vpp.bridge', 'member.interface', 'VPP bridge member'),
+    ('interfaces_vpp.xconnect', 'member.interface', 'VPP xconnect member'),
+]
+
+_VPP_INTERFACE_REFS = _VPP_FEATURE_INTERFACE_REFS + _VPP_MEMBER_INTERFACE_REFS
+
+
+def vpp_interface_in_use(
+    iface: str, config: dict, match_vlans: bool = False, refs: list = None
+):
+    """Check if an interface is referenced in VPP config.
+
+    Args:
+        iface: interface name to check (e.g. 'eth0' or 'eth0.100')
+        config: config dict
+        match_vlans: if True, also match VLAN subinterfaces (e.g. 'eth0.100')
+        refs: list of (path, inner_path, feature_name) tuples to scan.
+              Defaults to _VPP_INTERFACE_REFS (all refs).
+              Use _VPP_FEATURE_INTERFACE_REFS or _VPP_MEMBER_INTERFACE_REFS to narrow scope.
+
+    Returns:
+        feature_name (str) if found, None otherwise
+    """
+    if refs is None:
+        refs = _VPP_INTERFACE_REFS
+
+    def _matches(candidate):
+        """
+        Return True if 'candidate' matches 'iface' (optionally match subinterfaces).
+        'candidate' can be a string or a list/iterable of strings.
+        """
+        values = [candidate] if isinstance(candidate, str) else list(candidate)
+        for name in values:
+            if name == iface:
+                return True
+            if match_vlans and name.startswith(f'{iface}.'):
+                return True
+        return False
+
+    for path, inner_path, usage in refs:
+        data = dict_search(path, config)
+        if not data:
+            continue
+
+        if inner_path is not None:
+            for item_key, item_conf in data.items():
+                value = dict_search(inner_path, item_conf)
+                if value is not None and _matches(value):
+                    return usage
+        else:
+            if _matches(data):
+                return usage
+
+    return None
+
+
+def verify_vpp_remove_interface(iface: str, config: dict, match_vlans: bool = False):
+    """
+    Check that an interface is not referenced by any VPP feature.
+    Raises ConfigError if the interface is still referenced.
+    """
+    feature = vpp_interface_in_use(iface, config, match_vlans)
+    if feature:
+        raise ConfigError(
+            f'Cannot remove interface "{iface}", '
+            f'{"it or its VLAN " if match_vlans else "it "}is still configured as {feature} interface'
+        )
+
+
+def verify_vpp_interface_not_in_feature(iface: str, config: dict):
+    """Raise ConfigError if interface is used by a VPP feature (NAT, ACL, etc.).
+
+    Called from VPP interfaces scripts (bonding/bridge/xconnect) before adding a member.
+    """
+    feature = vpp_interface_in_use(iface, config, refs=_VPP_FEATURE_INTERFACE_REFS)
+    if feature:
+        raise ConfigError(
+            f'Interface {iface} is already used as {feature} interface '
+            f'and cannot be added as a member'
+        )
+
+
+def verify_vpp_interface_not_a_member(iface: str, config: dict):
+    """Raise ConfigError if interface is a member of bonding/bridge/xconnect.
+
+    Called from feature scripts (NAT, ACL, sFlow, etc.) before adding an interface.
+    """
+    member = vpp_interface_in_use(iface, config, refs=_VPP_MEMBER_INTERFACE_REFS)
+    if member:
+        raise ConfigError(
+            f'Interface {iface} is already used as {member} interface '
+            f'and cannot be added to a VPP feature'
+        )
+
 
 def verify_vpp_remove_xconnect_interface(config: dict):
     if not 'deleted' in config:
diff --git a/smoketest/scripts/cli/test_vpp.py b/smoketest/scripts/cli/test_vpp.py
index d4238f68c..8fcd541f0 100755
--- a/smoketest/scripts/cli/test_vpp.py
+++ b/smoketest/scripts/cli/test_vpp.py
@@ -873,6 +873,13 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         lines = out.split('\n')
         self.assertTrue(len(lines) == 3)
 
+        # Cannot remove inside/outside interface from vpp while it is used in the feature
+        # expect raise ConfigError
+        self.cli_delete(base_bond + [iface_bond, 'vif', vif_1])
+        with self.assertRaises(ConfigSessionError):
+            self.cli_commit()
+        self.cli_discard()
+
     def test_14_vpp_nat44(self):
         base_nat = base_path + ['nat', 'nat44']
         exclude_local_addr = '100.64.0.52'
@@ -1018,6 +1025,13 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         for expected_entry in expected_entries:
             self.assertIn(expected_entry, out)
 
+        # Cannot remove interface from vpp while it is used in the feature
+        # expect raise ConfigError
+        self.cli_delete(base_path + ['settings', 'interface', iface_2])
+        with self.assertRaises(ConfigSessionError):
+            self.cli_commit()
+        self.cli_discard()
+
         # cannot delete system sFlow configuration if VPP sFlow is configured
         # expect raise ConfigError
         self.cli_delete(base_sflow)
diff --git a/src/conf_mode/interfaces_ethernet.py b/src/conf_mode/interfaces_ethernet.py
index 2eb36a231..886f9b7b7 100755
--- a/src/conf_mode/interfaces_ethernet.py
+++ b/src/conf_mode/interfaces_ethernet.py
@@ -15,7 +15,6 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
-import re
 
 from sys import exit
 
@@ -47,6 +46,7 @@ from vyos.utils.dict import dict_to_paths_values
 from vyos.utils.dict import dict_set
 from vyos.utils.dict import dict_delete
 from vyos.utils.process import is_systemd_service_running
+from vyos.vpp.config_verify import verify_vpp_remove_interface
 from vyos.vpp.control_vpp import VPPControl
 from vyos import ConfigError
 from vyos import airbag
@@ -176,12 +176,20 @@ def get_config(config=None):
 
     ethernet['flowtable_interfaces'] = get_flowtable_interfaces(conf)
 
-    ethernet['vpp'] = conf.get_config_dict(
+    vpp_config = conf.get_config_dict(
         ['vpp'],
         key_mangling=('-', '_'),
         get_first_key=True,
         no_tag_node_value_mangle=True,
     )
+    if vpp_config:
+        ethernet['vpp'] = vpp_config
+        ethernet['vpp']['interfaces_vpp'] = conf.get_config_dict(
+            ['interfaces', 'vpp'],
+            key_mangling=('-', '_'),
+            get_first_key=True,
+            no_tag_node_value_mangle=True,
+        )
 
     # Protocols static arp dependency
     if 'static_arp' in ethernet:
@@ -353,23 +361,11 @@ def verify_flowtable(ethernet: dict):
 
 def verify_vpp_remove_vif(ethernet: dict):
     """Ensure that VIF interfaces being removed are not used by VPP features"""
-    vpp_paths_pattern = re.compile(
-        # Known paths that already use VLAN interfaces
-        r'(nat\.cgnat\.interface\.inside)|'
-        r'(nat\.cgnat\.interface\.outside)|'
-        r'(nat\.nat44\.interface\.inside)|'
-        r'(nat\.nat44\.interface\.outside)|'
-        # Potential paths for VLAN interfaces
-        r'(nat\.nat44\.address_pool\.translation\.interface)|'
-        r'(nat\.nat44\.address_pool\.twice_nat\.interface)|'
-        r'(nat\.nat44\.exclude\.rule\.(\d)+\.external_interface)|'
-        r'(interfaces\.bonding\.bond(\d)+\.member\.interface)|'
-        r'(interfaces\.bridge\.br(\d)+\.member\.interface)|'
-        r'(interfaces\.xconnect\.xcon(\d)+\.member\.interface)|'
-        r'(acl\.ip\.interface)|'
-        r'(acl\.mac\.interface)'
-    )
     ifname = ethernet['ifname']
+    vpp_config = ethernet.get('vpp')
+
+    if not vpp_config:
+        return
 
     vlan_names = [
         f'{ifname}.{vif_id}'
@@ -377,29 +373,8 @@ def verify_vpp_remove_vif(ethernet: dict):
         for vif_id in ethernet.get(vif_group, [])
     ]
 
-    if not vlan_names:
-        return
-
-    vpp_flat = dict_to_paths_values(ethernet.get('vpp', {}))
-
-    candidate_keys = []
-    for key, value in vpp_flat.items():
-        # Normalize values to list for consistent processing
-        values = value if isinstance(value, list) else [value]
-        if any(vlan in values for vlan in vlan_names):
-            candidate_keys.append((key, values))
-
-    if not candidate_keys:
-        return
-
-    for key, values in candidate_keys:
-        if vpp_paths_pattern.fullmatch(key):
-            used_vlans = [v for v in vlan_names if v in values]
-            if used_vlans:
-                raise ConfigError(
-                    f'Cannot delete interface "{used_vlans[0]}", '
-                    f'it is still in use by "vpp {key.replace(".", " ")}"'
-                )
+    for vlan in vlan_names:
+        verify_vpp_remove_interface(vlan, vpp_config)
 
 def verify(ethernet):
     verify_flowtable(ethernet)
diff --git a/src/conf_mode/vpp.py b/src/conf_mode/vpp.py
index 7b41c54fe..dc9ba9b7c 100755
--- a/src/conf_mode/vpp.py
+++ b/src/conf_mode/vpp.py
@@ -49,10 +49,8 @@ from vyos.utils.process import is_systemd_service_active
 from vyos.vpp import VPPControl
 from vyos.vpp import control_host
 from vyos.vpp import VppNotRunningError
-from vyos.vpp.config_deps import deps_bond_dict
-from vyos.vpp.config_deps import deps_bridge_dict
-from vyos.vpp.config_deps import deps_xconnect_dict
 from vyos.vpp.config_verify import (
+    verify_vpp_remove_interface,
     verify_vpp_minimum_cpus,
     verify_vpp_minimum_memory,
     verify_vpp_cpu_cores,
@@ -218,33 +216,6 @@ def _get_max_xdp_rx_queues(config: dict):
     return 1
 
 
-def _check_removed_interfaces(config: dict, feature_name: str, interfaces_config: dict):
-    """
-    Check if removed interfaces are used in any feature configuration
-
-    Args:
-        config: The main configuration dictionary
-        feature_name: Human-readable feature name for error messages
-        interfaces_config: The interfaces dictionary from the feature config
-    Example:
-        _check_removed_interfaces(config, 'IPFIX monitoring', config.get('ipfix', {}).get('interface', {}))
-    """
-    if (
-        'removed_ifaces' not in config
-        or not config['removed_ifaces']
-        or not interfaces_config
-    ):
-        return
-
-    for removed_iface in config['removed_ifaces']:
-        iface_name = removed_iface.get('iface_name')
-        if iface_name and iface_name in interfaces_config:
-            raise ConfigError(
-                f'Cannot remove interface {iface_name} - it is currently configured for {feature_name}. '
-                f'Remove it from {feature_name} configuration first.'
-            )
-
-
 def _is_device_allowed(config: dict, iface: str):
     """
     Determines if a network interface device is allowed to be used
@@ -295,10 +266,6 @@ def get_config(config=None):
         no_tag_node_value_mangle=True,
     )
 
-    xconn_members = deps_xconnect_dict(conf)
-    bridge_members = deps_bridge_dict(conf)
-    bond_members = deps_bond_dict(conf)
-
     removed_ifaces = []
     tmp = node_changed(conf, base_settings + ['interface'])
     if tmp:
@@ -337,9 +304,6 @@ def get_config(config=None):
             set_dependents('pppoe_server', conf)
         return {
             'removed_ifaces': removed_ifaces,
-            'xconn_members': xconn_members,
-            'bridge_members': bridge_members,
-            'bond_members': bond_members,
             'persist_config': eth_ifaces_persist,
             'interfaces_vpp': interfaces_config,
             'pppoe_ifaces': pppoe_ifaces,
@@ -503,9 +467,6 @@ def get_config(config=None):
 
     if removed_ifaces:
         config['removed_ifaces'] = removed_ifaces
-        config['xconn_members'] = xconn_members
-        config['bridge_members'] = bridge_members
-        config['bond_members'] = bond_members
 
     config['interfaces_vpp'] = interfaces_config
 
@@ -557,11 +518,6 @@ def get_config(config=None):
 
 
 def verify(config):
-    # Check remove VPP interface that used in IPFIX
-    _check_removed_interfaces(
-        config, 'IPFIX monitoring', config.get('ipfix', {}).get('interface', {})
-    )
-
     if config.get('interfaces_vpp') and 'remove' in config:
         raise ConfigError(
             'VPP cannot be removed while VPP interfaces exist. Remove all "interfaces vpp" first!'
@@ -580,6 +536,12 @@ def verify(config):
     if not config or 'remove' in config:
         return None
 
+    # Check removed interfaces (and their VLANs) against all VPP features
+    for removed_iface in config.get('removed_ifaces', []):
+        verify_vpp_remove_interface(
+            removed_iface['iface_name'], config, match_vlans=True
+        )
+
     if 'settings' not in config:
         raise ConfigError('"settings interface" is required but not set!')
 
@@ -685,21 +647,6 @@ def verify(config):
                     f'RX mode {rx_mode} is not supported for interface {iface}'
                 )
 
-    # Check if deleted interfaces are not xconnect/bridge/bond members
-    for iface_config in config.get('removed_ifaces', []):
-        if iface_config['iface_name'] in config.get('xconn_members', {}):
-            raise ConfigError(
-                f'Interface {iface_config["iface_name"]} is an xconnect member and cannot be removed'
-            )
-        if iface_config['iface_name'] in config.get('bridge_members', {}):
-            raise ConfigError(
-                f'Interface {iface_config["iface_name"]} is a bridge member and cannot be removed'
-            )
-        if iface_config['iface_name'] in config.get('bond_members', {}):
-            raise ConfigError(
-                f'Interface {iface_config["iface_name"]} is a bond member and cannot be removed'
-            )
-
     verify_routes_count(config['settings'])
 
     for pppoe_iface in config.get('changed_pppoe_ifaces', []):
diff --git a/src/conf_mode/vpp_acl.py b/src/conf_mode/vpp_acl.py
index 4d9ada4a1..ccbe11763 100644
--- a/src/conf_mode/vpp_acl.py
+++ b/src/conf_mode/vpp_acl.py
@@ -27,6 +27,7 @@ from vyos.utils.network import get_protocol_by_name
 
 from vyos.vpp.utils import cli_ifaces_list
 from vyos.vpp.acl import Acl
+from vyos.vpp.config_verify import verify_vpp_interface_not_a_member
 
 
 # TCP flag names to bit values
@@ -190,6 +191,14 @@ def get_config(config=None) -> dict:
     if effective_config:
         config.update({'effective': effective_config})
 
+    # VPP interface membership data for member-conflict checks
+    config['interfaces_vpp'] = conf.get_config_dict(
+        ['interfaces', 'vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -217,6 +226,7 @@ def verify(config):
                     raise ConfigError(
                         f'{iface} must be a VPP interface for ACL interface'
                     )
+                verify_vpp_interface_not_a_member(iface, config)
 
     if 'ip' in config:
         acl = config.get('ip')
diff --git a/src/conf_mode/vpp_interfaces_bonding.py b/src/conf_mode/vpp_interfaces_bonding.py
index 51272c087..7dba9fb3b 100644
--- a/src/conf_mode/vpp_interfaces_bonding.py
+++ b/src/conf_mode/vpp_interfaces_bonding.py
@@ -32,6 +32,8 @@ from vyos.vpp.config_deps import deps_xconnect_dict
 from vyos.vpp.config_verify import verify_member_conflicts
 from vyos.vpp.config_verify import verify_vpp_remove_bridge_interface
 from vyos.vpp.config_verify import verify_vpp_remove_xconnect_interface
+from vyos.vpp.config_verify import verify_vpp_remove_interface
+from vyos.vpp.config_verify import verify_vpp_interface_not_in_feature
 from vyos.vpp.utils import cli_ifaces_list
 
 
@@ -98,6 +100,13 @@ def get_config(config=None) -> dict:
         get_first_key=True,
         no_tag_node_value_mangle=True,
     )
+    # VPP config for member-in-feature checks
+    config['vpp'] = conf.get_config_dict(
+        ['vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
 
     config['bond_members'] = deps_bond_dict(conf)
 
@@ -150,6 +159,7 @@ def verify(config):
     verify_vpp_remove_bridge_interface(config)
 
     if 'deleted' in config:
+        verify_vpp_remove_interface(ifname, config.get('vpp'), match_vlans=True)
         return None
 
     if not is_systemd_service_active('vpp.service'):
@@ -170,6 +180,7 @@ def verify(config):
             )
 
         verify_member_conflicts(iface, config, 'bond')
+        verify_vpp_interface_not_in_feature(iface, config.get('vpp'))
 
         if mtu := config.get('mtu'):
             mtu = int(mtu)
@@ -199,6 +210,7 @@ def verify(config):
             raise ConfigError(
                 f'Cannot remove interface {vif_iface}: it is still in use by the PPPoE server'
             )
+        verify_vpp_remove_interface(vif_iface, config.get('vpp'))
 
     verify_mtu_ipv6(config)
 
diff --git a/src/conf_mode/vpp_interfaces_bridge.py b/src/conf_mode/vpp_interfaces_bridge.py
index 25fad5e5b..4d65690ce 100644
--- a/src/conf_mode/vpp_interfaces_bridge.py
+++ b/src/conf_mode/vpp_interfaces_bridge.py
@@ -26,6 +26,7 @@ from vyos.vpp.config_deps import deps_bond_dict
 from vyos.vpp.config_deps import deps_bridge_dict
 from vyos.vpp.config_deps import deps_xconnect_dict
 from vyos.vpp.config_verify import verify_member_conflicts
+from vyos.vpp.config_verify import verify_vpp_interface_not_in_feature
 
 
 def get_config(config=None) -> dict:
@@ -71,6 +72,14 @@ def get_config(config=None) -> dict:
     config['bridge_members'] = deps_bridge_dict(conf)
     config['xconn_members'] = deps_xconnect_dict(conf)
 
+    # VPP config for member-in-feature checks
+    config['vpp'] = conf.get_config_dict(
+        ['vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -108,6 +117,7 @@ def verify(config):
                 )
 
             verify_member_conflicts(member, config, 'bridge')
+            verify_vpp_interface_not_in_feature(member, config.get('vpp'))
 
             # Check if BVI is already defined, only one BVI per bridge domain is allowed
             if 'bvi' in member_config:
diff --git a/src/conf_mode/vpp_interfaces_xconnect.py b/src/conf_mode/vpp_interfaces_xconnect.py
index 91fa27c1b..29f2da520 100644
--- a/src/conf_mode/vpp_interfaces_xconnect.py
+++ b/src/conf_mode/vpp_interfaces_xconnect.py
@@ -26,6 +26,7 @@ from vyos.vpp.config_deps import deps_bond_dict
 from vyos.vpp.config_deps import deps_bridge_dict
 from vyos.vpp.config_deps import deps_xconnect_dict
 from vyos.vpp.config_verify import verify_member_conflicts
+from vyos.vpp.config_verify import verify_vpp_interface_not_in_feature
 from vyos.vpp.utils import cli_ifaces_list
 
 
@@ -67,6 +68,14 @@ def get_config(config=None) -> dict:
     config['xconn_members'] = deps_xconnect_dict(conf)
     config['vpp_ifaces'] = cli_ifaces_list(conf, 'candidate')
 
+    # VPP config for member-in-feature checks
+    config['vpp'] = conf.get_config_dict(
+        ['vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -100,6 +109,7 @@ def verify(config):
             )
 
         verify_member_conflicts(iface, config, 'xconn')
+        verify_vpp_interface_not_in_feature(iface, config.get('vpp'))
 
 
 def generate(config):
diff --git a/src/conf_mode/vpp_ipfix.py b/src/conf_mode/vpp_ipfix.py
index b69651ee4..8a7633389 100644
--- a/src/conf_mode/vpp_ipfix.py
+++ b/src/conf_mode/vpp_ipfix.py
@@ -21,6 +21,7 @@ from vyos.vpp.ipfix import IPFIX
 from vyos.vpp.utils import cli_ifaces_list
 from vyos.vpp.utils import vpp_iface_name_transform
 from vyos.vpp.control_vpp import VPPControl
+from vyos.vpp.config_verify import verify_vpp_interface_not_a_member
 
 
 def get_config(config=None) -> dict:
@@ -60,6 +61,14 @@ def get_config(config=None) -> dict:
     # Add list of VPP interfaces to the config
     config.update({'vpp_ifaces': cli_ifaces_list(conf)})
 
+    # VPP interface membership data for member-conflict checks
+    config['interfaces_vpp'] = conf.get_config_dict(
+        ['interfaces', 'vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -81,6 +90,7 @@ def verify(config):
             raise ConfigError(
                 f'{interface} must be a VPP interface for IPFIX monitoring'
             )
+        verify_vpp_interface_not_a_member(interface, config)
 
     # Verify that at least one collector is configured
     if 'collector' not in config:
diff --git a/src/conf_mode/vpp_nat_cgnat.py b/src/conf_mode/vpp_nat_cgnat.py
index 2044a07b9..838d13239 100644
--- a/src/conf_mode/vpp_nat_cgnat.py
+++ b/src/conf_mode/vpp_nat_cgnat.py
@@ -26,6 +26,7 @@ from vyos.vpp.utils import vpp_iface_name_transform
 from vyos.vpp.nat.det44 import Det44
 from vyos.vpp.control_vpp import VPPControl
 from vyos.vpp.config_verify import verify_nat_interfaces
+from vyos.vpp.config_verify import verify_vpp_interface_not_a_member
 
 protocol_map = {
     'all': 0,
@@ -118,6 +119,14 @@ def get_config(config=None) -> dict:
     if effective_config:
         config.update({'effective': effective_config})
 
+    # VPP interface membership data for member-conflict checks
+    config['interfaces_vpp'] = conf.get_config_dict(
+        ['interfaces', 'vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -157,6 +166,7 @@ def verify(config):
                 raise ConfigError(
                     f'{interface} must be a VPP interface for {direction} CGNAT interface'
                 )
+            verify_vpp_interface_not_a_member(interface, config)
 
     required_keys = {'outside_prefix', 'inside_prefix'}
     for rule in config['rule']:
diff --git a/src/conf_mode/vpp_nat_nat44.py b/src/conf_mode/vpp_nat_nat44.py
index 7f0b27541..8d69ee786 100644
--- a/src/conf_mode/vpp_nat_nat44.py
+++ b/src/conf_mode/vpp_nat_nat44.py
@@ -30,6 +30,7 @@ from vyos.vpp.utils import vpp_iface_name_transform
 from vyos.vpp.nat.nat44 import Nat44
 from vyos.vpp.control_vpp import VPPControl
 from vyos.vpp.config_verify import verify_nat_interfaces
+from vyos.vpp.config_verify import verify_vpp_interface_not_a_member
 
 
 protocol_map = {
@@ -124,6 +125,14 @@ def get_config(config=None) -> dict:
     if effective_config:
         config.update({'effective': effective_config})
 
+    # VPP interface membership data for member-conflict checks
+    config['interfaces_vpp'] = conf.get_config_dict(
+        ['interfaces', 'vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -171,6 +180,7 @@ def verify(config):
                 raise ConfigError(
                     f'{interface} must be a VPP interface for {direction} NAT interface'
                 )
+            verify_vpp_interface_not_a_member(interface, config)
 
     if not config.get('address_pool', {}).get('translation') and not config.get(
         'static', {}
diff --git a/src/conf_mode/vpp_sflow.py b/src/conf_mode/vpp_sflow.py
index df9d0365f..de592f514 100644
--- a/src/conf_mode/vpp_sflow.py
+++ b/src/conf_mode/vpp_sflow.py
@@ -19,6 +19,7 @@ from vyos import ConfigError
 from vyos.config import Config
 from vyos.vpp.utils import cli_ifaces_list
 from vyos.vpp.sflow import SFlow
+from vyos.vpp.config_verify import verify_vpp_interface_not_a_member
 
 
 def get_config(config=None) -> dict:
@@ -70,6 +71,14 @@ def get_config(config=None) -> dict:
     # Add list of VPP interfaces to the config
     config.update({'vpp_ifaces': cli_ifaces_list(conf)})
 
+    # VPP interface membership data for member-conflict checks
+    config['interfaces_vpp'] = conf.get_config_dict(
+        ['interfaces', 'vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return config
 
 
@@ -87,6 +96,7 @@ def verify(config):
             raise ConfigError(
                 f'{interface} must be a VPP interface for sFlow monitoring'
             )
+        verify_vpp_interface_not_a_member(interface, config)
 
     # Verify that system sflow has enable-vpp defined
     if 'system_sflow' not in config or 'vpp' not in config.get('system_sflow', {}):