INTERFACE_DISABLED state handling

[Jouni Malinen]

On Thu, Feb 16, 2012 at 05:02:48PM +0000, Madhvapathi Sriram wrote:
> However, there can be scenarios where rfkill is not forced and still a simple ip or net down is called on the interface (for example having been disassociated and hence there is not possible data link etc applications can call a ip or net down).  This sends a link change notification to the supplicant which (in rtm_newlink handling) moves the state to WPA_INTERFACE_DISABLED as per the new state changes.

> Now, if the application wanted to send a scan command to supplicant, then it would not be possible because the supplicant would reject it.

Correct. This is direction that the Linux drivers have moved to over the
years and I would expect most driver in the kernel tree to reject the
scan if the network interface is down. The interface down is more or
less same as powering down the radio in practice. It sounds reasonable
for wpa_supplicant to follow same design.

> If the supplicant expects that the state should always be moved to WPA_INTERFACE_ENABLED before SCAN, RECONNECT, REASSOSCIATE? Wouldn't that mean, the ip or net up needs to be done even if the net traffic cannot be started? Would not this mean providing a wrong status to the application?

The netdev needs to be up, but you do not need to set IP address on it.
The operation state of the interface can also indicate that normal data
traffic is not available before association.

-- 
Jouni Malinen                                            PGP id EFC895FA