T7950: VPP: Unexpected None interface in CGNAT when ethernet subinterface is removed from vif

Do not allow to delete subinterface if it is in use in VPP features

Author: natali-rs1985

src/conf_mode/interfaces_ethernet.py

@@ -15,6 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import re
 
 from sys import exit
 
@@ -171,6 +172,13 @@ def get_config(config=None):
 
     ethernet['flowtable_interfaces'] = get_flowtable_interfaces(conf)
 
+    ethernet['vpp'] = conf.get_config_dict(
+        ['vpp'],
+        key_mangling=('-', '_'),
+        get_first_key=True,
+        no_tag_node_value_mangle=True,
+    )
+
     return ethernet
 
 def verify_speed_duplex(ethernet: dict, ethtool: Ethtool):
@@ -301,8 +309,51 @@ def verify_flowtable(ethernet: dict):
                     if vifcname in ethernet['flowtable_interfaces']:
                         raise ConfigError(f'Cannot delete interface "{vifcname}", still referenced on a flowtable')
 
+def verify_vpp_remove_vif(ethernet: dict):
+    """Ensure that VIF interfaces being removed are not used by VPP features"""
+    possible_vpp_paths = [
+        # Known paths that already use VLAN interfaces
+        r'nat.cgnat.interface.inside',
+        r'nat.cgnat.interface.outside',
+        r'nat44.interface.inside',
+        r'nat44.interface.outside',
+        # Potential paths for VLAN interfaces
+        r'nat44.address_pool.translation.interface',
+        r'nat44.address_pool.twice_nat.interface',
+        r'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.macip.interface',
+    ]
+    ifname = ethernet['ifname']
+    vpp_flat = dict_to_paths_values(ethernet.get('vpp', {}))
+
+    for vif_group in ['vif_remove', 'vif_s_remove']:
+        for vif_id in ethernet.get(vif_group, []):
+            vif_name = f'{ifname}.{vif_id}'
+
+            # Find all VPP paths that reference this VIF
+            matching_paths = [
+                key
+                for pattern in possible_vpp_paths
+                for key, value in vpp_flat.items()
+                if re.fullmatch(pattern, key)
+                and (
+                    value == vif_name or (isinstance(value, list) and vif_name in value)
+                )
+            ]
+
+            if matching_paths:
+                raise ConfigError(
+                    f'Cannot delete interface "{vif_name}", it is still in use by '
+                    f'"vpp {matching_paths[0].replace(".", " ")}"'
+                )
+
 def verify(ethernet):
     verify_flowtable(ethernet)
+    verify_vpp_remove_vif(ethernet)
 
     if 'deleted' in ethernet:
         return None