From d15954775875f19ac8c9f26ba6248b24341e16ac Mon Sep 17 00:00:00 2001
From: Daniel Sheppard <dans@dansheps.com>
Date: Mon, 26 Aug 2024 23:57:55 -0500
Subject: [PATCH] Make changes to validation to account for M2M not being
 available under model in addition to not being able to check incoming vlans
 under same model.

---
 .../api/serializers_/device_components.py     | 21 +++++++++++++++++++
 netbox/dcim/forms/model_forms.py              | 20 ++++++++++++++++++
 netbox/dcim/models/device_components.py       |  8 ++-----
 3 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/netbox/dcim/api/serializers_/device_components.py b/netbox/dcim/api/serializers_/device_components.py
index d342a8c49..f26e81aa1 100644
--- a/netbox/dcim/api/serializers_/device_components.py
+++ b/netbox/dcim/api/serializers_/device_components.py
@@ -238,6 +238,27 @@ class InterfaceSerializer(NetBoxModelSerializer, CabledObjectSerializer, Connect
     def validate(self, data):
 
         if not self.nested:
+
+            # Validate 802.1q mode and vlan(s)
+            mode = None
+            tagged_vlans = []
+
+            if self.instance.pk and 'mode' in data.keys():
+                mode = data.get('mode') if 'mode' in self.data.keys() else self.instance.get('mode')
+            elif 'mode' in data.keys():
+                mode = data.get('mode')
+
+            if self.instance.pk and 'tagged_vlans' in data.keys():
+                tagged_vlans = data.get('tagged_vlans') if 'tagged_vlans' in data.keys() else \
+                    self.instance.tagged_vlans.all()
+            elif 'tagged_vlans' in data.keys():
+                tagged_vlans = data.get('tagged_vlans')
+
+            if mode != InterfaceModeChoices.MODE_TAGGED and tagged_vlans:
+                raise serializers.ValidationError({
+                    'tagged_vlans': "Interface mode does not support including tagged vlans"
+                })
+
             # Validate many-to-many VLAN assignments
             device = self.instance.device if self.instance else data.get('device')
             for vlan in data.get('tagged_vlans', []):
diff --git a/netbox/dcim/forms/model_forms.py b/netbox/dcim/forms/model_forms.py
index c12ddccde..a03175725 100644
--- a/netbox/dcim/forms/model_forms.py
+++ b/netbox/dcim/forms/model_forms.py
@@ -1363,6 +1363,26 @@ class InterfaceForm(InterfaceCommonForm, ModularDeviceComponentForm):
             'mode': '802.1Q Mode',
         }
 
+    def clean(self):
+        mode = None
+        tagged_vlans = []
+
+        if self.instance.pk and 'mode' in self.cleaned_data.keys():
+            mode = self.cleaned_data.get('mode') if 'mode' in self.cleaned_data.keys() else self.instance.get('mode')
+        elif 'mode' in self.cleaned_data.keys():
+            mode = self.cleaned_data.get('mode')
+
+        if self.instance.pk and 'tagged_vlans' in self.cleaned_data.keys():
+            tagged_vlans = self.cleaned_data.get('tagged_vlans') if 'tagged_vlans' in self.cleaned_data.keys() else\
+                self.instance.tagged_vlans.all()
+        elif 'tagged_vlans' in self.cleaned_data.keys():
+            tagged_vlans = self.cleaned_data.get('tagged_vlans')
+
+        if mode != InterfaceModeChoices.MODE_TAGGED and tagged_vlans:
+            raise forms.ValidationError({
+                'tagged_vlans': "Interface mode does not support including tagged vlans"
+            })
+
 
 class FrontPortForm(ModularDeviceComponentForm):
     rear_port = DynamicModelChoiceField(
diff --git a/netbox/dcim/models/device_components.py b/netbox/dcim/models/device_components.py
index b4382b455..101a1a459 100644
--- a/netbox/dcim/models/device_components.py
+++ b/netbox/dcim/models/device_components.py
@@ -894,6 +894,8 @@ class Interface(ModularComponentModel, BaseInterface, CabledObjectModel, PathEnd
                 raise ValidationError({'rf_channel_width': _("Cannot specify custom width with channel selected.")})
 
         # VLAN validation
+        if self.mode is None and self.untagged_vlan:
+            raise ValidationError({'untagged_vlan': _("Interface mode does not support including an untagged vlan.")})
 
         # Validate untagged VLAN
         if self.untagged_vlan and self.untagged_vlan.site not in [self.device.site, None]:
@@ -904,12 +906,6 @@ class Interface(ModularComponentModel, BaseInterface, CabledObjectModel, PathEnd
                 ).format(untagged_vlan=self.untagged_vlan)
             })
 
-        # Validate that tagged-all payload does not include tagged_vlans
-        if self.mode != InterfaceModeChoices.MODE_TAGGED and self.tagged_vlans:
-            raise ValidationError({
-                'tagged_vlans': "Interface mode does not support including tagged vlans"
-            })
-
     def save(self, *args, **kwargs):
 
         # Set absolute channel attributes from selected options