Only some (e.g. ethernet or wireguard) interfaces validate if the supplied VRF actually exists. If this is not validated, one can pass an invalid VRF to the system which generates an OSError exception
To reproduce
```
set interfaces vxlan vxlan1 vni 1000
set interfaces vxlan vxlan1 remote 1.2.3.4
set interfaces vxlan vxlan1 vrf smoketest
```
results in
```
Report time: 2024-07-23 09:14:17
Image version: VyOS 1.5-rolling-202407230021
Release train: current
Built by:
[email protected]
Built on: Tue 23 Jul 2024 00:22 UTC
Build UUID: 413a7534-617a-4e00-957f-f805c6b7fa23
Build commit ID: 67f8d13fc99e39
Architecture: x86_64
Boot via: installed image
System type: KVM guest
Hardware vendor: QEMU
Hardware model: Standard PC (i440FX + PIIX, 1996)
Hardware S/N:
Hardware UUID: 423379fe-7364-2d62-d562-ab995a3ed96d
Traceback (most recent call last):
File "/usr/libexec/vyos/conf_mode/interfaces_vxlan.py", line 254, in <module>
apply(c)
File "/usr/libexec/vyos/conf_mode/interfaces_vxlan.py", line 245, in apply
v.update(vxlan)
File "/usr/lib/python3/dist-packages/vyos/ifconfig/vxlan.py", line 201, in update
super().update(config)
File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 1611, in update
self.set_vrf(config.get('vrf', ''))
File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 614, in set_vrf
self.set_interface('vrf', vrf)
File "/usr/lib/python3/dist-packages/vyos/ifconfig/control.py", line 195, in set_interface
return self._set_command(self.config, name, value)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/vyos/ifconfig/control.py", line 122, in _set_command
return self._command_set[name].get('format', lambda _: _)(self._cmd(cmd))
^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/vyos/ifconfig/control.py", line 64, in _cmd
return cmd(command, self.debug)
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/vyos/utils/process.py", line 155, in cmd
raise OSError(code, feedback)
OSError: [Errno 255] failed to run command: ip link set dev vxlan1 master smoketest_mgmt
returned:
exit code: 255
```
## TODO
* Extend base_interface smoketests to always check if interface can be assigned to an invalid VRF - this must be handled by all interface `verify()` stages