undocumented capabilities/flags in ifconfig(1) and in the handbookj

[Bernhard Schmidt]

On Monday, April 25, 2011 17:58:02 Eitan Adler wrote:
> In ifconfig(1) under "list scan" and "list sta" a number of letters
> are documented.
> 
> 1) The same letters are documented for both of them - even though
> there are a different set of flags (list sta) or capabilities (list
> scan)
> 
> The letters 'I' 'c' 'C' 'B' 's' 'R' and 'D' are not documented as
> capabilities in the man page
> 
> While 'Q' 'N' 'R' 'M' 'M+' 'I' 'S+' 's' 't' and 'r' are the flags
> which are not currently documented in the man page
> 
> I have been trying to work my way through the code to understand what
> each of these mean: The following list is incomplete and probably
> inaccurate.
> 
> c / C - I'm unsure exactly what this means. something here is
> pollable. Lowercase c means that it is capable while uppercase means
> it is required. It appears to only be used in
> usr.sbin/bsnmpd/modules/snmp_wlan/wlan_sys.c
> s - documented only in the handbook:    Short slot time. Indicates
> that the 802.11g network is using a short slot time because there are
> no legacy (802.11b) stations present.
> I - documented only in the handbook:    IBSS/ad-hoc network. Indicates
> that the station is part of an ad-hoc network (in contrast to an ESS
> network).
> B - ?????
> R - station is 801.11/i RSN capable
> D - ?????
> Q - station is using/capable of using QoS
> N - ?????
> M - ?????
> M+ - ?????
> S+ - station is using 20Mhz short preamble as well as 40Mhz
> t / r - station is transmitting / receiving 802.11 n A - MSDU

I assume you've obtained those from getcaps()/getflags() in
sbin/ifconfig/ifieee80211.c? If so, that conditions there should
give you some clue about the purpose/meaning of the flags.

Some hints for caps:
- for c/C have a look at chapter 9.3 in IEEE802.11-2007 about PCF.
- B, also called PBCC, is a 802.11b add-on which defines 22M
  and 33M rates, haven't seen those yet.
- s: short slottime
- S: short preamble
- A: this is a frequency hoping features. I doubt that we currently
  support any FH hardware, so this might just be removed/ignored.
- D: Indicates that the ESS/IBSS supports OFDM rates, refer to 19.7.
- I: it's an IBSS
- E: It's an ESS
- P: privacy as in WEP is in use
- R: it's an RSN

for flags:
- A: node is authenticated
- Q: QoS/WME capable node
- E: indicates that the node supports the ERP rateset (a OFDM rate
  subset)
- P: node is in power save mode
- H: node is HT capable
- H+: node is HT capable and using htcompat mode
  (pre-11n-draft-stuff-thingy)
- W: node is using WPS (Wireless Protected Setup)
- N: quote: Transitional Security Network.  Permits clients to
  associate and use WEP while WPA is configured.
- T: transmit AMPDU support
- R: receive AMPDU support
- M: Spatial Multiplexing Power Save supported/enabled
- M+: Spatial Multiplexing Power Save + RTS supported/enabled
- I: RIFS - Reduced Inter-Frame Spacing supported
- S: short guard interval on 40MHz supported
- S+: short guard interval on 20 + 40MHz supported
- s: short guard interval on 20MHz supported
- t: transmit AMSDU supported
- r: receive AMSDU supported

HTH

> I am hoping to get a better understanding of what these mean so I can
> submit a diff against the man page and handbook.

Go for it!

-- 
Bernhard