Closes #3510: Add minimum/maximum prefix length enforcement for IPNetworkVar

CHANGELOG.md

@@ -6,6 +6,7 @@ v2.6.4 (FUTURE)
 * [#3027](https://github.com/netbox-community/netbox/issues/3028) - Add `local_context_data` boolean filter for devices
 * [#3318](https://github.com/netbox-community/netbox/issues/3318) - Increase length of platform name and slug to 100 characters
 * [#3341](https://github.com/netbox-community/netbox/issues/3341) - Enable inline VLAN assignment while editing an interface
+* [#3510](https://github.com/netbox-community/netbox/issues/3510) - Add minimum/maximum prefix length enforcement for `IPNetworkVar`
 
 ## Bug Fixes
 

netbox/extras/scripts.py

@@ -16,6 +16,7 @@ from mptt.models import MPTTModel
 
 from ipam.formfields import IPFormField
 from utilities.exceptions import AbortTransaction
+from utilities.validators import MaxPrefixLengthValidator, MinPrefixLengthValidator
 from .constants import LOG_DEFAULT, LOG_FAILURE, LOG_INFO, LOG_SUCCESS, LOG_WARNING
 from .forms import ScriptForm
 from .signals import purge_changelog
@@ -162,6 +163,21 @@ class IPNetworkVar(ScriptVariable):
     """
     form_field = IPFormField
 
+    def __init__(self, min_prefix_length=None, max_prefix_length=None, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self.field_attrs['validators'] = list()
+
+        # Optional minimum/maximum prefix lengths
+        if min_prefix_length is not None:
+            self.field_attrs['validators'].append(
+                MinPrefixLengthValidator(min_prefix_length)
+            )
+        if max_prefix_length is not None:
+            self.field_attrs['validators'].append(
+                MaxPrefixLengthValidator(max_prefix_length)
+            )
+
 
 #
 # Scripts

netbox/utilities/validators.py

@@ -1,6 +1,6 @@
 import re
 
-from django.core.validators import _lazy_re_compile, URLValidator
+from django.core.validators import _lazy_re_compile, BaseValidator, URLValidator
 
 
 class EnhancedURLValidator(URLValidator):
@@ -26,3 +26,19 @@ class EnhancedURLValidator(URLValidator):
         r'(?:[/?#][^\s]*)?'                 # Path
         r'\Z', re.IGNORECASE)
     schemes = AnyURLScheme()
+
+
+class MaxPrefixLengthValidator(BaseValidator):
+    message = 'The prefix length must be less than or equal to %(limit_value)s.'
+    code = 'max_prefix_length'
+
+    def compare(self, a, b):
+        return a.prefixlen > b
+
+
+class MinPrefixLengthValidator(BaseValidator):
+    message = 'The prefix length must be greater than or equal to %(limit_value)s.'
+    code = 'min_prefix_length'
+
+    def compare(self, a, b):
+        return a.prefixlen < b