Re: Recent fragility with if_wi, 802.11 adhoc/wep, and Tiger

On Tue, 19 Jul 2005, Sam Leffler wrote:

>> I fairly regularly use 802.11 adhoc with WEP to communicate between my 
>> 6.x/7.x FreeBSD notebook using if_wi, and my Apple PowerBook running 
>> Mac OS X Tiger.  A few days ago, when I updated from a June to a July 
>> HEAD revision, this became quite "fragile".  Specifically, I often find 
>> that the Mac can't send to the FreeBSD box (ARP fails, etc), and that 
>> sometimes it will give an error when I ask it to re-connect to the ad 
>> hoc network. I find that if I ifconfig down/up if_wi, and likewise turn 
>> off and on the wireless on the PowerBook, it seems to recover.  I've 
>> not had a chance to really try and diagnose this at all -- i.e., does 
>> tcpdump show packets on either end, 802.11 state machine, etc.  I was 
>> wondering if anyone else has seen this problem, though.
>
> You didn't provide any config info.  I recently noticed the wi driver 
> isn't hooked up properly to the net80211 layer causing link state events 
> to not be done properly (it appears disassoc events were being generated 
> but not assoc/reassoc events).  If you're using dhclient+adhoc mode then 
> this might be related.

It's an entirely manual configuration job:

   #!/bin/sh
   ifconfig wi0 ssid network wepmode on weptxkey 1 \
           wepkey 1:0xaaaaaaaaaaaaaaaaaaaaaaaaaa
   ifconfig wi0 mediaopt adhoc
   ifconfig wi0 inet 192.168.11.1
   ifconfig wi0 up
   ipfw delete 5005
   ipfw add 5005 allow tcp from any to any via wi0

Previously, this worked without a hitch, and I'll normally transfer 
several gigabytes of data.  Now it works for some period, then appears to 
wedge.  It will then recover after a few minutes, usually 5-10 minutes.

Robert N M Watson