From af2c20fb9017d0f2f4111fc1e4ae54a9b9f4bb69 Mon Sep 17 00:00:00 2001
From: Ember 'n0emis' Keske <git@n0emis.eu>
Date: Tue, 10 Feb 2026 14:11:49 +0100
Subject: [PATCH 1/2] Add feature-flag to allow private IPs on default vrf
 loopbacks

---
 cosmo/features.py      | 6 +++++-
 cosmo/routervisitor.py | 3 ++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/cosmo/features.py b/cosmo/features.py
index 403542c..b28a045 100644
--- a/cosmo/features.py
+++ b/cosmo/features.py
@@ -97,5 +97,9 @@ def exe_with_feature(*args, **kwargs):
 
 
 features = FeatureToggle(
-    {"interface-auto-descriptions": True, "new-bgp-cpe-group-naming": False}
+    {
+        "interface-auto-descriptions": True,
+        "new-bgp-cpe-group-naming": False,
+        "allow-private-ips-default-vrf": False,
+    }
 )
diff --git a/cosmo/routervisitor.py b/cosmo/routervisitor.py
index 0e43864..37fb867 100644
--- a/cosmo/routervisitor.py
+++ b/cosmo/routervisitor.py
@@ -19,6 +19,7 @@
 from cosmo.vrfhelper import TVRFHelpers
 from cosmo.manufacturers import ManufacturerFactoryFromDevice
 from cosmo.routerbgpcpevisitor import RouterBgpCpeExporterVisitor
+from cosmo.features import features
 from cosmo.routerl2vpnvisitor import (
     RouterL2VPNValidatorVisitor,
     RouterL2VPNExporterVisitor,
@@ -54,7 +55,7 @@ def __init__(
         self.l2vpn_validator = RouterL2VPNValidatorVisitor(loopbacks=loopbacks, asn=asn)
         self.bgpcpe_exporter = RouterBgpCpeExporterVisitor()
         self.loopbacks = loopbacks
-        self.allow_private_ips = False
+        self.allow_private_ips = features.featureIsEnabled("allow-private-ips-default-vrf")
         self.asn = asn
 
     def getASN(self) -> int:

From cfcbbc96c9a6fda984550131129140e346d1cfbc Mon Sep 17 00:00:00 2001
From: Ember 'n0emis' Keske <git@n0emis.eu>
Date: Tue, 10 Feb 2026 14:18:14 +0100
Subject: [PATCH 2/2] add feature flag to run without loopback interface type
 in netbox

---
 cosmo/clients/netbox_v4.py |  3 +--
 cosmo/features.py          |  1 +
 cosmo/netbox_types.py      | 15 ++++++++++-----
 cosmo/routervisitor.py     |  4 +++-
 cosmo/tests/utils.py       |  2 +-
 5 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/cosmo/clients/netbox_v4.py b/cosmo/clients/netbox_v4.py
index 2bc9450..a8486ed 100644
--- a/cosmo/clients/netbox_v4.py
+++ b/cosmo/clients/netbox_v4.py
@@ -126,8 +126,7 @@ def _fetch_data(self, kwargs, pool):
             """
             query{
               interface_list(filters: {
-                name: {starts_with: "lo"},
-                type: {exact:"loopback"}
+                name: {starts_with: "lo"}
               }) {
                 __typename
                 name,
diff --git a/cosmo/features.py b/cosmo/features.py
index b28a045..2d53a03 100644
--- a/cosmo/features.py
+++ b/cosmo/features.py
@@ -101,5 +101,6 @@ def exe_with_feature(*args, **kwargs):
         "interface-auto-descriptions": True,
         "new-bgp-cpe-group-naming": False,
         "allow-private-ips-default-vrf": False,
+        "netbox-loopback-interface-type": False,
     }
 )
diff --git a/cosmo/netbox_types.py b/cosmo/netbox_types.py
index 6d37980..86f1234 100644
--- a/cosmo/netbox_types.py
+++ b/cosmo/netbox_types.py
@@ -17,6 +17,7 @@
     head,
     CosmoOutputType,
 )
+from .features import features
 from typing import (
     Self,
     Iterator,
@@ -675,11 +676,15 @@ def isLoopbackOrParentIsLoopback(self) -> bool:
                 )
             return parent_interface.isLoopbackOrParentIsLoopback()
         elif self.getName().startswith("lo"):
-            raise InterfaceSerializationError(
-                f"Interface {self.getName()} is named as a loopback but is not marked"
-                f"as such in the data source, please fix.",
-                on=self,
-            )
+            if self.getAssociatedType() != "loopback" and features.featureIsEnabled(
+                "netbox-loopback-interface-type"
+            ):
+                raise InterfaceSerializationError(
+                    f"Interface {self.getName()} is named as a loopback but is not marked"
+                    f"as such in the data source, please fix.",
+                    on=self,
+                )
+            return True
         return False
 
     def getIPAddresses(self) -> list[IPAddressType]:
diff --git a/cosmo/routervisitor.py b/cosmo/routervisitor.py
index 37fb867..91897eb 100644
--- a/cosmo/routervisitor.py
+++ b/cosmo/routervisitor.py
@@ -55,7 +55,9 @@ def __init__(
         self.l2vpn_validator = RouterL2VPNValidatorVisitor(loopbacks=loopbacks, asn=asn)
         self.bgpcpe_exporter = RouterBgpCpeExporterVisitor()
         self.loopbacks = loopbacks
-        self.allow_private_ips = features.featureIsEnabled("allow-private-ips-default-vrf")
+        self.allow_private_ips = features.featureIsEnabled(
+            "allow-private-ips-default-vrf"
+        )
         self.asn = asn
 
     def getASN(self) -> int:
diff --git a/cosmo/tests/utils.py b/cosmo/tests/utils.py
index 7eab04f..cc31ec7 100644
--- a/cosmo/tests/utils.py
+++ b/cosmo/tests/utils.py
@@ -76,7 +76,7 @@ def patchPostFunc(url, json, **kwargs):
                     retVal["interface_list"] = patchKwArgs.get(
                         "connected_devices_interface_list", []
                     )
-                elif "loopback" in q:
+                elif 'starts_with: "lo"' in q:
                     retVal["interface_list"] = patchKwArgs.get(
                         "loopback_interface_list", []
                     )