[Xastir] Xastir on the Raspberry Pi

[AC]

That's not quite true.  The function of wpa_supplicant is to provide WPA
services to legacy wireless devices that don't utilize hardware WPA
modes.  There is no feature of wpa_supplicant that will shut down
another interface.  By way of example my laptop running Debian Wheezy
uses wpa_supplicant for an old Linksys PCMCIA wifi card but it leaves
the wired interface (eth0) up and running.

What some people may see if they use a feature such as Ubuntu's Network
Manager is that Network Manager itself brings up and down the interfaces
silently in the background.  If NM is asked to bring the wireless up it
frequently makes the assumption (unless instructed otherwise) that you
don't want a wired connection and brings the wired interface down.

Since this is an RPi which doesn't use Network Manager, there is no
mechanism to bring up or down the other interface by way of
wpa_supplicant alone.  Indeed some people use RPi as a wireless to wired
bridge/access point which would preclude turning off the wired connection.

My suspicion is that the real problem lies in the routing table changing
when the AX.25 port is brought online.  Most likely the default gateway
switches from the wireless port to the AX.25 port which would cause
various connection issues including dropped connections.  Plugging in
the ethernet cable after this event occurs likely triggers a hot-plug
event (eth0 cable connected) which then resets the interface and brings
it up.  This will again rewrite the routing tables and now the
connections will use the wired ethernet interface as the default
gateway.  It all amounts to which was the last interface to be brought
online (in this instance first was wireless, second AX.25, finally wired
ethernet) that ends up rewriting the routing table and leaving it in a
state pointing to that final interface.

The first thing to do is to observe the routing table via an out-of-band
method (e.g. serial port console) when the AX.25 port is brought online
starting with a wifi-only configuration.  If the routing table changes
(as I suspect it does) then the solution is to modify the networking
rules to either prevent the AX.25 stack from changing the routing rules
or to modify the script to restore the routing rules after the AX.25
port is brought up.

On 11/15/2013 05:07, Kris Wotipka wrote:
> Max,
> 
> You will need to look into how the wpa_supplicant handles network
> connections.  Its purpose is to only allow one active network
> connection.  So if you are wireless and you plug in a ethernet cable,
> then it shuts down the wireless connection.  I guess this is ment to
> help the novices not have any network issues but it drives people nuts. 
> I am guessing that is what is happening here because you are "attaching"
> in a sense another network interface.
> 
> hope this helps
> 
> kw