bluetooth4LE: BTLE_ADV PDU_type enum typo fix

[antoniovazquezblanco]

Checklist:

• If you are new to Scapy: I have checked CONTRIBUTING.md (esp. section submitting-pull-requests)
• I squashed commits belonging together
• I added unit tests or explained why they are not relevant
• I executed the regression tests (using cd test && ./run_tests or tox)
• If the PR is still not finished, please create a Draft Pull Request

The referenced documentation in the code shows a slightly different name. See below.

[XenoKovah]

FWIW this isn't actually a typo, the packet used to legitimately be called CONNECT_REQ in BT Core spec <= 4.2, but as of 5.0 they changed it to CONNECT_IND (and we're now on BT Spec 6.0), so it'd just be good to get this synced up with the latest specs.

[antoniovazquezblanco]

Oh, makes sense. I went directly to the referenced Core v5.2 in the code and the new name was used...

Thanks!

[gpotter2]

Got it, thanks for the explanation and thanks for the PR!

[XenoKovah]

@gpotter2 I was wondering whether this was going to get rejected on backwards-compatibility grounds (i.e. if the name changes, anyone who used to use CONNECT_REQ will now need to update their code to use CONNECT_IND otherwise it will not work with the latest.) I'm pleased to see that wasn't a blocker. So I just wanted to know what the general Scapy policy is on such things? Because I've just been running my needed changes (including this one) over in a fork, but for instance I saw there were plenty of places where there was inconsistent naming of the same field in different packets (presumably because they were added by different people at different times). So I was wondering whether you'd be open to future PRs which harmonize BT field naming, at the expense of backwards compatibility?

[gpotter2]

We try to maximize compatibility, especially with fields names (where we have a special deprecated_fields attribute to allow for backwards compatibility).

We should probably invest in having the same for enums, but since we currently don't it's up to a case to case basis. I personally like having up-to-date spec names, and I don't think that Scapy's bluetooth layer is used much in an environment that is even remotely close to production.