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

@@ -171,6 +171,13 @@ 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 +308,31 @@ 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"""
+    ifname = ethernet['ifname']
+
+    vpp_dict_paths = dict_to_paths_values(ethernet.get('vpp'))
+
+    for vif_type in ['vif_remove', 'vif_s_remove']:
+        for vif in ethernet.get(vif_type, []):
+            vif_name = f'{ifname}.{vif}'
+
+            vif_in_vpp = [
+                k
+                for k, v in vpp_dict_paths.items()
+                if v == vif_name or (isinstance(v, list) and vif_name in v)
+            ]
+
+            if vif_in_vpp:
+                raise ConfigError(
+                    f'Cannot delete interface "{vif_name}", it is still in use by '
+                    f'"vpp {vif_in_vpp[0].replace(".", " ")}"'
+                )
+
 def verify(ethernet):
     verify_flowtable(ethernet)
+    verify_vpp_remove_vif(ethernet)
 
     if 'deleted' in ethernet:
         return None