Create prefix within container automatically

[ya-cha]

NetBox version

v.4.0.10

Feature type

New functionality

Proposed functionality

When creating a prefix in other prefixes, Netbox is looking for the next available. This happens in the user interface /ipam/prefixes/add/?prefix={id} and in the API /api/ipam/prefixes/{id}/available-prefixes/.
If there are child prefixes with the status container, I would expect those containers to be used when finding the next free one (so creating a prefix inside the container inside the given prefix).

Use case

For internal purposes (rDNS) the prefix used for our customers is divided in multiple containers. The Netbox considers it as completely full. In our understanding the purpose of containers is not to block prefixes but to group them. I would expect the Netbox to create a prefix in the container.

Database changes

To prevent breaking changes this behaviour could be managed in a feature flag. This would be a DB change

External dependencies

No response