On Saturday 21 March 2009 17:39:23 Johannes Berg wrote:
> It might be nicer sometimes to allow mode changes while the
> interface is up, e.g. from managed to ibss mode, so that IP
> configuration is retained. This patch changes mac80211 to
> support that, it effectively internally behaves as though
> you had actually done a down/change/up cycle.
>
> Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
> ---
> COMPLETELY UNTESTED. If anyone needs this functionality
> please test and adopt this patch -- I have no interest in
> pushing it into the kernel.
>
> net/mac80211/iface.c | 36 +++++++++++++++++++++++++-----------
> 1 file changed, 25 insertions(+), 11 deletions(-)
>
> --- wireless-testing.orig/net/mac80211/iface.c 2009-03-21 17:20:23.000000000 +0100
> +++ wireless-testing/net/mac80211/iface.c 2009-03-21 17:26:59.000000000 +0100
> @@ -749,24 +749,22 @@ static void ieee80211_setup_sdata(struct
> int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
> enum nl80211_iftype type)
> {
> - ASSERT_RTNL();
> + int ret = 0;
> + bool running = false;
> + enum nl80211_iftype oldtype;
>
> - if (type == sdata->vif.type)
> - return 0;
> + ASSERT_RTNL();
>
> /* Setting ad-hoc mode on non-IBSS channel is not supported. */
> if (sdata->local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS &&
> type == NL80211_IFTYPE_ADHOC)
> return -EOPNOTSUPP;
>
> - /*
> - * We could, here, on changes between IBSS/STA/MESH modes,
> - * invoke an MLME function instead that disassociates etc.
> - * and goes into the requested mode.
> - */
> + oldtype = sdata->vif.type;
> + running = netif_running(sdata->dev);
>
> - if (netif_running(sdata->dev))
> - return -EBUSY;
> + if (running)
> + ieee80211_stop(sdata->dev);
>
> /* Purge and reset type-dependent state. */
> ieee80211_teardown_sdata(sdata->dev);
> @@ -778,7 +776,23 @@ int ieee80211_if_change_type(struct ieee
> sdata->local->hw.conf.channel->band);
> sdata->drop_unencrypted = 0;
>
> - return 0;
> + if (running) {
> + ret = ieee80211_open(sdata->dev);
> + if (ret) {
> + /*
> + * ieee80211_open could fail, for example if the user
> + * wants to have an interface combination now that we
> + * do not support -- in that case roll back. This has
> + * to succeed unless we have a driver/mac80211 bug,
> + * since the interface was there before!
What about memory allocation failures?
I think we should check for an error and if one occurs take the interface
completely down and return the error to userspace.
> + */
> + ieee80211_teardown_sdata(sdata->dev);
> + ieee80211_setup_sdata(sdata, oldtype);
> + WARN_ON(ieee80211_open(sdata->dev));
> + }
> + }
> +
> + return ret;
> }
--
Greetings, Michael.
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