On Apr 9, 2011, at 1:02 PM, Grant Erickson wrote:
> FWIW and FYI, I am currently debugging an issue in which connman gets into an
> inconsistent state with respect to technologies and devices. When there are
> local connectivity problems, my application--for good or bad--periodically
> attempts to bring down and back up the network interface by executing the
> following connman .Manager methods:
>
> ...
>
> However, at times this results in a state in which the device and interface
> are DOWN yet connman believes the technology to be active and enabled:
>
> ...
>
> While I haven't yet caught why connman gets into this state, with the
> debugger, I can make a single variable change in which connman gets its state
> normalized again, the device and interface come up and all is good again:
>
> ...
>
> Interactive debugging aside, the only other way to get out of this state is
> to restart the system or connman, in particular.
>
> From what I can see of the overall function trace flow for
> net.connman.Manager.{Disable,Enable}Technology, writing "Powered=<state>"
> early in the method handling could lead to a state in which the persistent
> and internal states disagree:
>
> ...
For those following this thread, I've distilled this down to a script that can
reproduce this in about five minutes or so:
#!/bin/sh
log_info() {
local stamp=`date "+%FT%T"`
echo "${stamp}: $*"
echo "${stamp}: `hostname`: $*" 2>&1 | nc -w 5 ubuntu.local 6845
}
enable_technology() {
dbus-send --system --dest=net.connman --print-reply /
net.connman.Manager.EnableTechnology string:"wifi"
}
disable_technology() {
dbus-send --system --dest=net.connman --print-reply /
net.connman.Manager.DisableTechnology string:"wifi"
}
check_profile() {
grep -r '^Powered=' /var/lib/connman/
}
while [ 1 ]; do
log_info "Enabling Wi-Fi."
enable_technology
check_profile
sleep 5
log_info "Starting ping test."
ping ubuntu.local -c 10
log_info "Ping test exited with status $?."
log_info "Disabling Wi-Fi."
disable_technology
check_profile
sleep 15
done
Running this script, the failure seems to always be preceded by a timeout that
follows the disable request:
...
--- ubuntu.local ping statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max = 105.133/163.327/215.850 ms
Ping test exited with status 0.
Disabling Wi-Fi.
Error net.connman.Error.OperationTimeout: Operation timeout
/var/lib/connman/default.profile:Powered=false
Enabling Wi-Fi.
nc: timed out
Error net.connman.Error.AlreadyEnabled: Already enabled
/var/lib/connman/default.profile:Powered=false
Starting ping test.
...
...
--- ubuntu.local ping statistics ---
10 packets transmitted, 10 packets received, 0% packet loss
round-trip min/avg/max = 31.555/118.661/307.220 ms
Ping test exited with status 0.
Disabling Wi-Fi.
Error net.connman.Error.OperationTimeout: Operation timeout
/var/lib/connman/default.profile:Powered=false
Enabling Wi-Fi.
nc: timed out
Error net.connman.Error.AlreadyEnabled: Already enabled
/var/lib/connman/default.profile:Powered=false
Starting ping test.
nc: timed out
ADDRCONF(NETDEV_UP): wlan0: link is not ready
ping: bad address 'ubuntu.local'
Ping test exited with status 1.
nc: timed out
Disabling Wi-Fi.
nc: timed out
Error net.connman.Error.Failed: No such device
/var/lib/connman/default.profile:Powered=false
Enabling Wi-Fi.
nc: timed out
Error net.connman.Error.AlreadyEnabled: Already enabled
...
Regards,
Grant
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