Adding an initial '.' to a sysObjectID value in NAV's type registry prevents ipdevpoll and SeedDB from detecting the vendor ID properly

[lunkwill42]

Describe the bug

A customer accidentally changed the sysObjectID value of one of the Netbox Type entries in SeedDB. Changing it back, a leading . was added to the sysObjectID value. While this seems perfectly reasonable (seeing as how this is normally how OIDs are presented), NAV's type registry has the quirk that sysObjectID values must be entered without the leading dot.

However, there is nothing that verifies the value or gives any user feedback about invalid values.

It turns out NetboxType.get_enterprise_id() doesn't handle a sysObjectID value with a leading dot, and returns None rather than a proper enterprise id number (like 9 for Cisco).

This in turn causes ipdevpoll to be unable to detect the proper vendor for devices of this type. Many ipdevpoll plugins will therefore opt to not select vendor-specific MIBs, causing various functionality to fail (such as vendor specific sensor collection, CPU and memory collection, or even power supply and fan monitoring).

Another quirk that appears when this happens, is that SeedDB is now unable to detect an existing type entry for devices of this type when using the "check connectivity" button (even though the IP Device is already associated with the correct type entry).

To Reproduce

1. Find any IP device with vendor specific support in NAV (e.g. Cisco)
2. Find the IP device's associated type entry in SeedDB
3. Edit the type's sysObjectID value, prefixing the existing value with a leading .
4. Run ipdevpoll collection
5. Observe that vendor-specific functionality stops working

Expected behavior

1. NetboxType.get_enterprise_id() should be able to detect an enterprise id from a sysObjectID with a leading .

2. SeedDB should be able to associate a collected sysObjectID value with one from the type registry, even if it is stored with a leading ..

3. Optionally, SeedDB and the Type model should refuse to accept values with a leading . if this isn't supposed to work.

Environment (please complete the following information):

• NAV version installed: 5.6.0

[lunkwill42]

This method explicitly only checks for a non-dotted enterprise prefix:

nav/python/nav/models/manage.py

Lines 1278 to 1291 in 97fc362

	def get_enterprise_id(self):
	"""Returns the type's enterprise ID as an integer.
	The type's sysobjectid should always start with
	SNMPv2-SMI::enterprises (1.3.6.1.4.1). The next OID element will be
	an enterprise ID, while the remaining elements will describe the type
	specific to the vendor.
	"""
	prefix = u"1.3.6.1.4.1."
	if self.sysobjectid.startswith(prefix):
	specific = self.sysobjectid[len(prefix) :]
	enterprise = specific.split('.')[0]
	return int(enterprise)