[PATCH] Make roc duration configurable

[Sujith Manoharan]

Jouni Malinen wrote:
> Wouldn't such use cases benefit from being able to set this dynamically
> at runtime? The design used here seems to limit this to a one-time
> configuration option when starting the interface.
> 
> In addition, I'd assume it would be useful to do such limitation on
> off-channel operations mainly when there is concurrent operations in
> progress (one or more wpa_s instances connected as a station or
> operating as an AP). Or is the goal really to limit the operation
> duration even if there is no such concurrent tasks on the radio?

Yes, even if there is only a single GO interface, for example, offchannel
duration needs to be limited.

> This is the parser for the new config variable, but there should be a
> matching change in config_file.c to write the config variable (if
> non-zero, i.e., not the default value).

I'll fix this.

> This is the only place where wpa_s->max_remain_on_chan gets updated.
> First of all, this must not allow the driver-advertised value to be
> increased (that would result in driver commands getting rejected).
> Secondly, this would be nice to be able to update at runtime based on
> current use case. In other words, it may be useful to keep
> wpa_s->max_remain_on_chan as-is and use wpa_s->conf->max_remain_on_chan
> to reduce that limit in the concurrent cases so that changes to
> wpa_s->conf->max_remain_on_chan will be taken into use on the next
> attempt. min() of those two (if wpa_s->conf->max_remain_on_chan != 0)
> would likely be the best approach for this.

I'll make these changes and send a v2.

Sujith