Given the simple netgraph infrastructure to extrude an 802.1ad vlan (2) from an interface (lagg1) (and vice versa)
```
+ mkpeer lagg1 vlan lower downstream
+ name lagg1.lower vlag
+ msg vlag setencapproto 0x88A8
+ mkpeer vlag eiface test ether
+ msg vlag addfilter { vid=2 hook="test" }
+ mkpeer vlag eiface nomatch ether
# tcpdump -eni ngeth1 # nomatch
```
An unpatched 13-STABLE does spit out 802.1q frames on the "nomatch" hook which are displayed by tcpdump as
```
09:22:35 aa:aa:aa:aa:aa > bb:bb:bb:bb:bb:bb ethertype 802.1Q (0x8100), length 68: vlan 2, p 0, ethertype ...
```
After applying the patch, the netgraph node ng_vlan(4) connected to
the lower hook of ng_ether(4) is able to handle the frames accordingly
to the ethertype correctly.