allow .igmpize() on IGMPv3 packet types

[Radvendii]

This is marked as a draft because I'm having trouble adding tests. When I run test/run_tests it doens't seem to run any of the contrib tests. Is that by design? Can I turn those on?

Also, the guidelines say no unnecessary lists. I think value in [item1, item2, item3, item4] is a whole lot more readable / maintainable / etc than value == item1 or value == item2 or value == item3 or value == item4 but I can change it if that's really better.

This PR allows you to run .igmpize() on IGMPv3 packets that are a type that didn't exist in IGMP. It shouldn't affect too much. I think there may still be some issues in IGMPv3 that I'll have to fix in a separate pull request.

fixes #2536

[codecov]

Codecov Report

Merging #2537 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2537      +/-   ##
==========================================
- Coverage   87.72%   87.72%   -0.01%     
==========================================
  Files         242      242              
  Lines       51089    51111      +22     
==========================================
+ Hits        44818    44836      +18     
- Misses       6271     6275       +4     

Impacted Files	Coverage Δ
scapy/contrib/igmp.py	100.00% <100.00%> (ø)
scapy/layers/http.py	84.54% <0.00%> (-1.08%)	⬇️
scapy/arch/linux.py	75.60% <0.00%> (-0.88%)	⬇️
scapy/arch/bpf/supersocket.py	76.41% <0.00%> (-0.58%)	⬇️
scapy/layers/tftp.py	89.39% <0.00%> (-0.29%)	⬇️
scapy/layers/inet6.py	83.73% <0.00%> (+0.05%)	⬆️
scapy/contrib/isotp.py	90.36% <0.00%> (+0.08%)	⬆️
scapy/sendrecv.py	85.57% <0.00%> (+0.16%)	⬆️
scapy/contrib/igmpv3.py	91.37% <0.00%> (+1.72%)	⬆️
scapy/autorun.py	72.85% <0.00%> (+3.57%)	⬆️

[gpotter2]

Hi & thanks for the PR.
You can add your tests to https://github.com/secdev/scapy/blob/master/test/contrib/igmpv3.uts
To test them, you could simply use tox, or you can use ./run_tests -t test/contrib/.../igmpv3.uts. You can ./run_tests -h to see all available options.

[Radvendii]

Okay, thanks. I made sure my test succeeds (but fails if my changes aren't applied).

Earlier, the Travis CI build was failling, but I couldn't figure out why. Or rather, it seemed unrelated to my change. It says ###(012)=[failed] Test DTC scan
Any help on that front?

[guedou]

It looks good to me. Could you remove the draft when you are ready?

[Radvendii]

Sure. Some tests still seem to be failing, but it's a different test than it was before. I'm guessing this is one of those things where you eventually learn when you can safely ignore the big red X 😛

[guedou]

The only red mark is from the code coverage tool. Its result could slightly change depending on the network packets received during the tests. Here the difference is really small.