net80211: adjust more VHT structures/fields

[bz]

Summary

Replace ieee80211_ie_vhtcap with ieee80211_vht_cap and
ieee80211_ie_vht_operation with ieee80211_vht_operation.
The "ie" version has the two bytes type/length at the beginning which
we did not actually use as such (the one place doing did just as unused
extra work).

Using the non-"ie" versions allows us to re-use them on shared code.
Using an enum helps us to not accidentally get unsuppored or unhandled
values.

ieee80211_vht_operation is guarded by _KERNEL/WANT_NET80211. While the
header is supposed to be exported to user land historically, software
such as wpa bring their own structure definitions. For in-tree usage
it is only ifconfig which really cares (at least for now).

Sponsored by: The FreeBSD Foundation
MFC after: 3 days

[bz]

Any comments?

[adrian]

sorry! looks good, I was sick the last couple weeks and missed that. :(

[cc]

Sorry, not sure how this is missing in my radar. Please allow one day or two to finish my review.

[cc]

sbin/ifconfig/ifieee80211.c

2784

Because "struct ieee80211_ie_vhtcap" is removed, can we add a comment that explains why this "+2" offset is used?

2816

Same here. Because "struct ieee80211_ie_vht_operation" is removed, can we add a comment that explains why this "+2" offset is used?

sys/net80211/ieee80211.h

885

Why not use the matching enum data type for this "chan_width" variable? Like this illustration:

typedef enum ieee80211_vht_chanwidth {...} ieee80211_vht_chanwidth;

struct ieee80211_vht_operation {
	ieee80211_vht_chanwidth			chan_width;
...
}

[bz]

sbin/ifconfig/ifieee80211.c

2784

You find ie+2, 2+X, x[2], .. in other places; e.g., printssid(), printies(), ... for data and/or length.
I think it is generally understood that an ie (information element) is a TLV and we skip the TL (elemid, length) in those cases.

What we probably should do is make sure that ie[1] is the proper length.
Something the already existing vht prints do not seem to have (no one passes in size_t ielen = 2 + ie[1] as was done for others; not that we need that length as ie[1] is avail).

I'll add the assertion which then can probably make this more explanatory or can get a comment.

sys/net80211/ieee80211.h

885

Because we need something 8bit wide. While enums are integers their size if compiler dependent. Doesn't work.

[bz]

Check length in ifoccnfig for the Element information and print error/return
if not matching. With that initialize variables later and add the requested
comment from cc@ to explain the +2.

[cc]

Looks good to me now. Thanks for the update.