added duplicates() method to IPAddress and Prefix model managers.

refactored condition on IPAddress and Prefix clean method to use new
manager method.

netbox/ipam/models.py

@@ -262,6 +262,12 @@ class PrefixQuerySet(NullsFirstQuerySet):
             return queryset
         return filter(lambda p: p.depth <= limit, queryset)
 
+    def duplicates(self, prefix):
+        return self.filter(
+            vrf=prefix.vrf,
+            prefix=str(prefix)
+        ).exclude(pk=prefix.pk)
+
 
 class Prefix(CreatedUpdatedModel, CustomFieldModel):
     """
@@ -299,7 +305,6 @@ class Prefix(CreatedUpdatedModel, CustomFieldModel):
         return reverse('ipam:prefix', args=[self.pk])
 
     def clean(self):
-
         # Disallow host masks
         if self.prefix:
             if self.prefix.version == 4 and self.prefix.prefixlen == 32:
@@ -311,6 +316,16 @@ class Prefix(CreatedUpdatedModel, CustomFieldModel):
                     'prefix': "Cannot create host addresses (/128) as prefixes. Create an IPv6 address instead."
                 })
 
+        if ((not self.vrf and settings.ENFORCE_GLOBAL_UNIQUE) or (self.vrf and self.vrf.enforce_unique)):
+            dupes = Prefix.objects.duplicates(self)
+            if dupes:
+                raise ValidationError({
+                    'prefix': "Duplicate prefix found in {}: {}".format(
+                        "VRF {}".format(self.vrf) if self.vrf else "global table",
+                        dupes.first(),
+                    )
+                })
+
     def save(self, *args, **kwargs):
         if self.prefix:
             # Clear host bits from prefix
@@ -361,6 +376,12 @@ class IPAddressManager(models.Manager):
         qs = super(IPAddressManager, self).get_queryset()
         return qs.annotate(host=RawSQL('INET(HOST(ipam_ipaddress.address))', [])).order_by('family', 'host')
 
+    def duplicates(self, ip_obj):
+        return self.filter(
+            vrf=ip_obj.vrf,
+            address__net_host=str(ip_obj.address.ip)
+        ).exclude(pk=ip_obj.pk)
+
 
 class IPAddress(CreatedUpdatedModel, CustomFieldModel):
     """
@@ -401,21 +422,22 @@ class IPAddress(CreatedUpdatedModel, CustomFieldModel):
         return reverse('ipam:ipaddress', args=[self.pk])
 
     def clean(self):
-
-        # Enforce unique IP space if applicable
-        if self.vrf and self.vrf.enforce_unique:
-            duplicate_ips = IPAddress.objects.filter(vrf=self.vrf, address__net_host=str(self.address.ip))\
-                .exclude(pk=self.pk)
-            if duplicate_ips:
+        if ((not self.vrf and settings.ENFORCE_GLOBAL_UNIQUE) or (self.vrf and self.vrf.enforce_unique)):
+            dupes = IPAddress.objects.duplicates(self)
+            if dupes:
                 raise ValidationError({
-                    'address': "Duplicate IP address found in VRF {}: {}".format(self.vrf, duplicate_ips.first())
+                    'address': "Duplicate IP address found in global table: {}".format(dupes.first())
                 })
-        elif not self.vrf and settings.ENFORCE_GLOBAL_UNIQUE:
-            duplicate_ips = IPAddress.objects.filter(vrf=None, address__net_host=str(self.address.ip))\
-                .exclude(pk=self.pk)
-            if duplicate_ips:
+
+        # Enforce unique IP space if applicable
+        if ((not self.vrf and settings.ENFORCE_GLOBAL_UNIQUE) or (self.vrf and self.vrf.enforce_unique)):
+            dupes = IPAddress.objects.duplicates(self)
+            if dupes:
                 raise ValidationError({
-                    'address': "Duplicate IP address found in global table: {}".format(duplicate_ips.first())
+                    'address': "Duplicate IP address found in {}: {}".format(
+                        "VRF {}".format(self.vrf) if self.vrf else "global table",
+                        dupes.first(),
+                    )
                 })
 
     def save(self, *args, **kwargs):