Monitor mode not working for iwi(4) on 7.X

[Bernhard Schmidt]

On Friday 08 October 2010 18:59:44 Paul B Mahol wrote:
> On 10/8/10, Alexey Dokuchaev <danfe at freebsd.org> wrote:
> > On Fri, Oct 08, 2010 at 03:20:08PM +0000, Paul B Mahol wrote:
> >> On 10/8/10, Alexey Dokuchaev <danfe at freebsd.org> wrote:
> >> > On Thu, Oct 07, 2010 at 08:43:37PM +0200, Bernhard Schmidt wrote:
> >> >> Try the attached patch, this is basically the code from stable/6
> >> >> ported to head and stable/7. I did only some basic tests but monitor
> >> >> mode seems to work and it is still possible to use the card in STA
> >> >> mode.
> >> > 
> >> > Unfortunately, I am getting instant panic when trying any of
> >> > aircrack-ng suite utilities ("ifconfig iwi0 scan/list scan" works
> >> > though):
> >> > 
> >> > Fatal trap 12: page fault while in kernel mode
> >> > processor eflags        = interrupt enabled, resume, IOPL = 0
> >> > current process         = 35 (iwi0 taskq)
> >> > 
> >> > Any suggestions?
> >> 
> >> 7.X is buggy regarding taskqueue, I think (maybe it is net80211 bug
> >> and not iwi fault).
> > 
> > That's a sad thing to hear about stable branch.
> > 
> >> Does it panic with tcpdump too?
> > 
> > Bernhard's tests indicate it's not.  However, me doing "ifconfig iwi0
> > mediaopt monitor" here resulted in immediate panic (did not catch the
> > core this time, but I'm positive it's the same as with aircrack-ng).
> 
> Looks like SMP issue.
> Let me look if it is something obvious.

After having another cup of coffee it's pretty obvious what's wrong.. and I 
really wonder how that could have worked during my tests yesterday. Just to be 
sure I did the same tests again today and it still worked. The only difference 
between what I did and your scenario is, that I didn't use
ifconfig iwi0 mediaopt monitor
but
ifconfig iwi0 monitor
instead.. anyways..

ic != sc

Attached patched should behave better now.

alix# kldload if_iwi
iwi0: <Intel(R) PRO/Wireless 2200BG> mem 0xe0040000-0xe0040fff irq 10 at 
device 
12.0 on pci0
iwi0: Ethernet address: 00:16:6f:64:37:68
iwi0: [ITHREAD]
kalix# kldload wlan_scan_sta
alix# ifconfig iwi0 -mediaopt monitor
alix# ifconfig iwi0 channel 1 up
alix# aireplay-ng -9 iwi0
00:34:10  Trying broadcast probe requests...
00:34:12  No Answer...
00:34:12  Found 1 AP 

00:34:12  Trying directed probe requests...
00:34:12  00:15:6D:84:06:6B - channel: 1 - 'aplab'
wi_write(): Input/output error
wi_write(): Input/output error
^C/ 6:   0%
alix# tcpdump -nei iwi0 -y IEEE802_11_RADIO
tcpdump: data link type IEEE802_11_RADIO                                        
tcpdump: WARNING: iwi0: no IPv4 address assigned                                
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode      
listening on iwi0, link-type IEEE802_11_RADIO (802.11 plus BSD radio 
information
 header), capture size 96 bytes                                                 
00:37:56.039527 1.0 Mb/s 2412 MHz 11g antenna 0 37dB signal 
BSSID:00:15:6d:84:06
:6b DA:ff:ff:ff:ff:ff:ff SA:00:15:6d:84:06:6b Beacon (aplab) [1.0* 2.0* 5.5* 
11.
0* 6.0 9.0 12.0 18.0 Mbit] ESS CH: 1, PRIVACY 

-- 
Bernhard
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