Fix compile_filter on *BSD with non-ether linktypes

[gpotter2]

• fixes sr with filter not working on loopback on OpenBSD #4627

I really have no idea why this line exists in the first place. It makes very little sense to me

[gpotter2]

Ah I see, to allow to compile filters without root. I mean if the filters it compiles are broken it's not that useful.

Shouldn't be hard to fix if the interface type is provided from PFROUTE.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.10%. Comparing base (7275516) to head (14658e5).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4670      +/-   ##
==========================================
+ Coverage   81.90%   82.10%   +0.20%     
==========================================
  Files         359      359              
  Lines       86574    86615      +41     
==========================================
+ Hits        70909    71118     +209     
+ Misses      15665    15497     -168     

Files with missing lines	Coverage Δ
scapy/arch/bpf/pfroute.py	92.51% <100.00%> (+0.04%)	⬆️
scapy/arch/common.py	68.96% <100.00%> (-1.04%)	⬇️
scapy/data.py	90.83% <ø> (ø)

... and 25 files with indirect coverage changes

[sthen]

Great, confirmed this fixes things for me. Many thanks!