iwn0 gets confused about channel and frequency and cannot connect to AP

[Ottavio Caruso <ottavio2006-netbsd%yahoo.com@localhost>]

Hello,

it's no secret that the iwn(4) driver cannot handle 5Ghz and 11n
properly. The interface can see these access points, but cannot
connect to them, or so it emerges by doing a search on the mailing
lists archives [see:
http://mail-index.netbsd.org/current-users/2014/09/02/msg025725.html ]

What happens to me is that I have this AP that I want to connect to,
and has been configured by admin to broadcast on channel 48 and 5Ghz.

My Thinkpad X61 comes with a 4965AGN Intel card and can connect to
this host fine with Linux or Windows 7, but not NetBSD.

The latter sees the access point as a normal 2.4 Ghz host on channel 11:

#wlanctl iwn0
iwn0: mac e0:3f:49:6a:87:ec bss e0:3f:49:6a:87:ec
        node flags 0004<scan>
        ess <5Ghz-access-point>
        chan 11 freq 2462MHz flags 04e0<cck,ofdm,2.4GHz,dynamic cck-ofdm>
        capabilities 0111<ess,privacy>
        beacon-interval 100 TU tsft 337491046458 us
        rates *6.0 9.0 *12.0 18.0 *24.0 36.0 48.0 [54.0]
        assoc-id 0 assoc-failed 0 inactivity 300s
        rssi 194 txseq 0 rxseq 62496


But this is incorrect, because admin has given me a screenshot of the
configuration and it's definitely a 5Ghz host, as confirmed under
Linux:

root@sysresccd /root % iwlist wls3 scan
wls3      Scan completed :
          Cell 01 - Address: E0:3F:49:6A:87:EC
                    Channel:48
                    Frequency:5.24 GHz (Channel 48)
                    Quality=45/70  Signal level=-65 dBm
                    Encryption key:on
                    ESSID:"5Ghz-access-point"
                    Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s
                              36 Mb/s; 48 Mb/s; 54 Mb/s
                    Mode:Master
                    Extra:tsf=0000004e0f09fba8
                    Extra: Last beacon: 54ms ago
                    IE: Unknown:
00204269726D696E6768616D43656E7472616C4261636B7061636B6572733547687A
                    IE: Unknown: 01088C129824B048606C
                    IE: Unknown:
073C4742202401172801172C01173001173401173801173C011740011764011E68011E6C011E70011E74011E78011E7C011E80011E84011E88011E8C011E
                    IE: Unknown: 200100
                    IE: Unknown: 23021000
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (2) : CCMP TKIP
                        Authentication Suites (1) : PSK
                    IE: Unknown:
2D1AED091BFFFFFF0000000000000000000000000000000000000000
                    IE: Unknown:
3D1630080400000000000000000000000000000000000000
                    IE: Unknown: DD090010180205F03C0000
                    IE: WPA Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (2) : CCMP TKIP
                        Authentication Suites (1) : PSK
                    IE: Unknown:
DD180050F2020101800003A4000027A4000042435E0062322F00


Both Linux and NetBSD use /lib/firmware/iwlwifi-4965-2.ucode, so it
can't be a firmware problem.

When using wpa_gui under NetBSD the interface tries to connect but it
get rejected.

I have also tried:
# ifconfig iwn0 chan 48

but it didn't make any difference.

I have no idea why this happens, but I guess it must be a bug in the
driver implementation of the 802.11n protocol.

If the interface cannot handle this protocol, it should either ignore
the AP or fail noisily and as soon as possible.

Debugging the driver is beyond my skills, although with a bit of
guidance I could try to give it a look.

In the meantime I wonder if filing a bug report is worth it.