Re: WiFi AP selection

[Dan Williams <dcbw redhat com>]

On Tue, 2019-10-22 at 13:37 -0700, Clive McCarthy wrote:
> I rand the commands you suggested but the response doesn't look like
> a log dump. I guess they just enable logging.
>
> method return time=1571775394.161873 sender=:1.8 ->
> destination=:1.507 serial=32493 reply_serial=2
> method return time=1571775429.864202 sender=:1.8 ->
> destination=:1.508 serial=32496 reply_serial=2
> method return time=1571775528.578915 sender=:1.8 ->
> destination=:1.510 serial=32636 reply_serial=2
>
> Can you point me to where the log files might be or at least their
> names.

If your distribution uses systemd, they may be available with:

journalctl -b -u wpa_supplicant

if your distro does not uses systemd, then it'll be wherever syslog
dumps that kind of output, like:

/var/log/messages
/var/log/wpa_supplicant.log
/var/log/daemon.log

Dan

> On 10/22/19 12:16 PM, Dan Williams wrote:
> > On Tue, 2019-10-22 at 11:17 -0700, Clive McCarthy wrote:
> > > Thanks for your reply.
> > > My laptop, when first opened, reports (via the Network Manage, I
> > > suppose) that it is disconnected from the network. After a second
> > > or
> > > two it reports being connected. And it is. However, as I noted,
> > > the
> > > manager seems to choose the last known connection. This is a
> > > satisfactory algorithm for a fixed computer and for a computer
> > > connecting to a single AP. It isn't good for a movable computer
> > > with
> > > multiple APs.
> > >
> > > The Intel WiFi adapter is forced to shutdown when the computer is
> > > closed because there is a bug in the Intel-WiFi driver that
> > > doesn't
> > > handle suspend correctly. That is why there is a disconnect-
> > > connect
> > > sequence.
> >
> > In this case we'd need the wpa_supplicant logs described below to
> > diagnose why the supplicant is picking that specific AP rather than
> > another.
> >
> > Dan
> >
> >
> > > On 10/22/19 10:05 AM, Dan Williams wrote:
> > > > On Mon, 2019-10-21 at 20:42 -0700, Clive McCarthy via
> > > > networkmanager-
> > > > list wrote:
> > > > > I have a situation where I have multiple APs in a building
> > > > > all
> > > > > with
> > > > > the same SSID and WPA key but set to non-clashing
> > > > > frequencies.
> > > > > When I
> > > > > close my laptop and WiFi shuts down and I move to a new
> > > > > location
> > > > > the
> > > > > Network Manager seems to connect to the original AP, rather
> > > > > than
> > > > > one
> > > > > with a much stronger signal.
> > > > >
> > > > > The algorithm for AP connection is suboptimal (in other words
> > > > > dumb).
> > > > > The selection process should scan ALL APs, figure out which
> > > > > ones
> > > > > are
> > > > > known (SSID and WPA); measure their signal strength and then
> > > > > choose
> > > > > the known AP with the strongest signal.
> > > > >
> > > > > How hard is that?
> > > >
> > > > This is what NetworkManager should already be doing.
> > > >
> > > > Two things to check:
> > > >
> > > > 1) NetworkManager depends on being notified by systemd or
> > > > upower
> > > > that
> > > > the laptop has suspended so that it can reconfigure when it
> > > > wakes
> > > > up.
> > > > It should be pretty clear if that's happening through the
> > > > NetworkManager logs because it will say that it's going to
> > > > sleep
> > > > and
> > > > waking up. For example:
> > > >
> > > > NetworkManager[1198]: <info>  [1571720491.7590] manager: sleep:
> > > > sleep requested (sleeping: no  enabled: yes)
> > > > NetworkManager[1198]: <info>  [1571720491.7599] device
> > > > (wlp61s0):
> > > > state change: disconnected -> unmanaged (reason 'sleeping',
> > > > sys-
> > > > iface-state: 'managed')
> > > > NetworkManager[1198]: <info>  [1571720491.7615] manager:
> > > > NetworkManager state is now ASLEEP
> > > > NetworkManager[1198]: <warn>  [1571752873.5481] sup-
> > > > iface[0x55f38553aaa0,wlp61s0]: connection disconnected (reason
> > > > -3)
> > > > NetworkManager[1198]: <info>  [1571752873.5504] device
> > > > (wlp61s0):
> > > > supplicant interface state: completed -> disconnected
> > > > NetworkManager[1198]: <info>  [1571752873.5803] manager: sleep:
> > > > wake requested (sleeping: yes  enabled: yes)
> > > > NetworkManager[1198]: <info>  [1571752873.6556] device
> > > > (wlp61s0):
> > > > state change: activated -> unmanaged (reason 'sleeping', sys-
> > > > iface-
> > > > state: 'managed')
> > > >
> > > > 2) enabling debug logging in wpa_supplicant with these two
> > > > commands
> > > > will show you exactly what's going on:
> > > >
> > > > sudo dbus-send --system --print-reply --
> > > > dest=fi.w1.wpa_supplicant1
> > > > /fi/w1/wpa_supplicant1 org.freedesktop.DBus.Properties.Set
> > > > string:fi.w1.wpa_supplicant1 string:DebugTimestamp
> > > > variant:boolean:true
> > > > sudo dbus-send --system --print-reply --
> > > > dest=fi.w1.wpa_supplicant1
> > > > /fi/w1/wpa_supplicant1 org.freedesktop.DBus.Properties.Set
> > > > string:fi.w1.wpa_supplicant1 string:DebugLevel
> > > > variant:string:"msgdump"
> > > >
> > > > this will dump logs to wherever your system typically sends
> > > > system
> > > > logs, like the systemd journal or syslog. Once you have these
> > > > logs,
> > > > please review them to ensure there is no private information
> > > > and
> > > > then
> > > > attach them to a reply so that we can figure out what's going
> > > > on.
> > > >
> > > > Thanks!
> > > > Dan
> > >
> > >  
>