cfg80211: add remain-on-channel command

Add new commands for requesting the driver to remain awake
on a specified channel for the specified amount of time
(and another command to cancel such an operation). This
can be used to implement userspace-controlled off-channel
operations, like Public Action frame exchange on another
channel than the operation channel.

The off-channel operation should behave similarly to scan,
i.e. the local station (if associated) moves into power
save mode to request the AP to buffer frames for it and
then moves to the other channel to allow the off-channel
operation to be completed. The duration parameter can be
used to request enough time to receive a response from
the target station.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 27 insertions, 14 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index a46ac6c9b365..bf1737fc9a7e 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -41,44 +41,57 @@ rdev_fixed_channel(struct cfg80211_registered_device *rdev,
 	return result;
 }
 
-int rdev_set_freq(struct cfg80211_registered_device *rdev,
-		  struct wireless_dev *for_wdev,
+struct ieee80211_channel *
+rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
 		  int freq, enum nl80211_channel_type channel_type)
 {
 	struct ieee80211_channel *chan;
 	struct ieee80211_sta_ht_cap *ht_cap;
-	int result;
-
-	if (rdev_fixed_channel(rdev, for_wdev))
-		return -EBUSY;
-
-	if (!rdev->ops->set_channel)
-		return -EOPNOTSUPP;
 
 	chan = ieee80211_get_channel(&rdev->wiphy, freq);
 
 	/* Primary channel not allowed */
 	if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
-		return -EINVAL;
+		return NULL;
 
 	if (channel_type == NL80211_CHAN_HT40MINUS &&
 	    chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
-		return -EINVAL;
+		return NULL;
 	else if (channel_type == NL80211_CHAN_HT40PLUS &&
 		 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
-		return -EINVAL;
+		return NULL;
 
 	ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
 
 	if (channel_type != NL80211_CHAN_NO_HT) {
 		if (!ht_cap->ht_supported)
-			return -EINVAL;
+			return NULL;
 
 		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
 		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
-			return -EINVAL;
+			return NULL;
 	}
 
+	return chan;
+}
+
+int rdev_set_freq(struct cfg80211_registered_device *rdev,
+		  struct wireless_dev *for_wdev,
+		  int freq, enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_channel *chan;
+	int result;
+
+	if (rdev_fixed_channel(rdev, for_wdev))
+		return -EBUSY;
+
+	if (!rdev->ops->set_channel)
+		return -EOPNOTSUPP;
+
+	chan = rdev_freq_to_chan(rdev, freq, channel_type);
+	if (!chan)
+		return -EINVAL;
+
 	result = rdev->ops->set_channel(&rdev->wiphy, chan, channel_type);
 	if (result)
 		return result;