Use correct getter function to get per-interface vlan.native value (#2041)

Fixes #2032 using a solution by @jbemmel

Author: ipspace

netsim/modules/vlan.py

@@ -304,7 +304,7 @@ def validate_link_vlan_attributes(link: Box,v_attr: Box,topology: Box) -> bool:
                 f'Node {intf.node} is using native VLAN without VLAN trunk\n... {link}',
                 log.IncorrectValue,
                 'vlan')
-            elif not intf.vlan.native in node_trunk:              # ... native VLAN not in trunk, that's not valid
+            elif node_native not in node_trunk:                   # ... native VLAN not in trunk, that's not valid
               log.error(
                 f'Node {intf.node} is using native VLAN that is not defined in its VLAN trunk\n... {link}',
                 log.IncorrectValue,

tests/topology/expected/vlan-trunk-native.yml

@@ -154,7 +154,9 @@ links:
       native: green
       trunk:
         blue: {}
-        green: {}
+        green:
+          vlan:
+            mode: irb
         red: {}
   - _vlan_mode: irb
     ifindex: 5
@@ -540,7 +542,9 @@ nodes:
         native: green
         trunk:
           blue: {}
-          green: {}
+          green:
+            vlan:
+              mode: irb
           red: {}
         trunk_id:
         - 1002

tests/topology/input/vlan-trunk-native.yml

@@ -41,6 +41,7 @@ links:
     vlan.native: green
   h1:
 - s1:
+    vlan.trunk.green.vlan.mode: irb         # A no-op to trigger #2032
   s2:
   vlan:
     trunk: [red, blue, green]