kern/57992: urtwn (and athn) driver lost network when WIFI router changes channel

[ea1abz%gmail.com@localhost]

>Number:         57992
>Category:       kern
>Synopsis:       urtwn (and athn) driver lost network when WIFI router changes channel
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar 03 10:40:00 +0000 2024
>Originator:     Ramiro Aceves
>Release:        10.0_RC5
>Organization:
>Environment:
NetBSD netbsd-raspa 10.0_RC5 NetBSD 10.0_RC5 (RPI) #0: Tue Feb 27 05:27:39 UTC 2024  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/RPI evbarm

>Description:
Hello,

I am using urtwn driver in my RaspberryPi Zero W with a TPLink TL-WN-725N WIFI dongle.

If I force a channel change in the router, the network is lost and I cannot recover it. "service wpa_supplicant restart" does not recover network. "ifconfig urtwn0 down" and up does not fix it.

I have also noticed the same behaviour in my Acer Aspire One amd64 laptop that uses athn driver. But in this case "service wpa_supplicant restart" recovers network.

Just when network fails I recorded the output of the following commands:


# ifconfig urtwn0
urtwn0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	ssid MiFibra-3422 nwkey 65536:"",0x433cc28429aedde0f4f22d14c5032697,"",""
	powersave off
	bssid 60:8d:26:32:34:24 chan 1
	address: e4:fa:c4:52:ac:4c
	media: IEEE802.11 autoselect (OFDM54 mode 11g)
	status: active
	inet6 fe80::e6fa:c4ff:fe52:ac4c%urtwn0/64 flags 0 scopeid 0x1
	inet 192.168.1.230/24 broadcast 192.168.1.255 flags 0
# wpa_cli status
Selected interface 'urtwn0'
22:32:36.067: bssid=60:8d:26:32:34:24
freq=0
ssid=MiFibra-3422
id=0
mode=station
pairwise_cipher=CCMP
group_cipher=CCMP
key_mgmt=WPA2-PSK
wpa_state=COMPLETED
ip_address=192.168.1.230
address=e4:fa:c4:52:ac:4c

I am not using dhcpd, I use static IP address.

netbsd-raspa# cat /etc/rc.conf
...
...
 
}

rc_configured=YES

hostname=netbsd-raspa
dhcpcd=NO

auto_ifconfig=YES
#ifconfig_bwfm0="inet 192.168.1.230 netmask 255.255.255.0"
ifconfig_urtwn0="inet 192.168.1.230 netmask 255.255.255.0"
wpa_supplicant=YES
wpa_supplicant_flags="-B -s -i urtwn0 -D bsd -c /etc/wpa_supplicant.conf"
defaultroute=192.168.1.1
no_swap=YES
savecore=NO
sshd=YES
ntpd=YES
ntpd_flags="-g"
creds_msdos=YES
creds_msdos_partition=/boot
certctl_init=YES
resize_disklabel=YES
resize_root=YES
resize_root_flags="-p"
resize_root_postcmd="/sbin/reboot -n"
wscons=YES
devpubd=YES
nettest=YES

minidlna=YES

This is weird because some times early in the night, I think my ISP makes mantainance operations in the router that change router settings. I have configured a fixed 11 channel setup and after several days it changed to auto channel without doing anything on my side. Perhaps they update firmware when they want. Who knows...

I have a rebooting script that reboots the machine if ping to www.google.com fails 3 times spaced at 5 minutes intervals, just to ensure not loosing SSH access to the headless Raspberry Pi. 

Thanks so much.
Ramiro







>How-To-Repeat:
Change WIFI channel in the router and network is lost.
>Fix:
Configure the router at a fixed channel (not a real fix)