Re: [gentoo-user] Choose a wireless access point

[Michael]

On Tuesday, 5 April 2022 08:46:52 BST Neil Bothwick wrote:
> On Tue, 5 Apr 2022 11:16:10 +0800, William Kenworthy wrote:
> > On 5/4/22 07:09, Michael wrote:
> > > On Monday, 4 April 2022 16:12:53 BST Jack wrote:
> > >> On 4/4/22 01:31, William Kenworthy wrote:
> > >>> Is there a way force openrc and wpa_supplicant to map a particular
> > >>> access point to an interface or fail?
> > >>>
> > >>> I have two AP's (each on a different ssid) to connect to so have two
> > >>> wifi interfaces - unfortunately they are not equal so I want wlan0
> > >>> to connect to only one particular AP, and wlan1 to the other ...
> > >>> reliably! I can manually force it to connect but invariably at the
> > >>> first glitch they both end up connected to the same AP (usually the
> > >>> strongest which is often not what I want :(
> > >>>
> > >>> BillK
> > >>
> > >> I don't know about wpa-supplicant, but I'm using open-rc and KDE, and
> > >> KDE's systemsettings Network / Connections screen lets you restrict a
> > >> network connection so a specific device.  Not sure if this helps you
> > >> any, but it would indicate that what you want is possible.
> > >>
> > >> Jack
> > >
> > > Look at the example provided in:
> > >
> > > /usr/share/doc/netifrc-0.7.3/net.example.bz2
> > >
> > > You can set a different ssid for each wireless NIC.  The
> > > wpa_supplicant can be set with credentials for the two APs only.
> >
> > Unfortunately, this does not work as I want ...wpa_supplicant's
> > behaviour makes sense in that it provides a fallback if the allocated
> > access point cant connect ... it will pick the next available one
> > (seemingly based on signal strength) if it is in its conf file (and
> > does not care that its another ssid) - so it does not fail.  As only
> > one of the two networks has internet access the device often ends up
> > not being able to be connected to (its headless so that's a problem!).
> >
> > I have fallen back to openrc for the main connection and will do the
> > other manually - it would be nice to have everything properly
> > controlled but its not working for me.
>
> Could you run two instances of wpa_suplicant, each listening on a
> different interface and using a config with only the AP for that
> interface?

As I recall wpa_cli can be launched by specifying a particular interface.  
Therefore two instances of wpa_cli launched by a script should be possible.

However, isn't the purpose of /etc/conf.d/net to specify how individual 
interfaces are configured?  I still think - but have not tried it - each 
wireless NIC can be configured via this file to use a particular access point/
channel and not go scanning for others, while the wpa_supplicant can be left 
to deal with the authentication mechanism after each NIC has found its 
specified ESSID.

The section in the netifrc example file which starts as follows, merits 
reading:

###############################################
# SETTINGS
# Hard code an SSID to an interface - leave this unset if you wish the driver
# to scan for available Access Points . . . 

Something like this ought to work:

essid_wlan0="foo"

essid_wlan1="bar"