nl/cfg80211: force scan using an AP vif if requested

If the user wants to scan using a vif configured as AP,
cfg80211 must give him a chance to do it, even if this
will disrupt the stations performance due to off-channel
scanning. To do so, this patch adds a 'force' flag to the
SCAN_TRIGGER command which tells cfg80211 to perform the
scanning operation even if the vif is an AP and the
beaconing has already started.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 13 insertions, 2 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 5739bfbf2999..5eab1325a0f6 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1855,7 +1855,16 @@ static int ieee80211_scan(struct wiphy *wiphy,
                  * beaconing hasn't been configured yet
                  */
         case NL80211_IFTYPE_AP:
-                if (sdata->u.ap.beacon)
+                /*
+                 * If the scan has been forced (and the driver supports
+                 * forcing), don't care about being beaconing already.
+                 * This will create problems to the attached stations (e.g. all
+                 * the  frames sent while scanning on other channel will be
+                 * lost)
+                 */
+                if (sdata->u.ap.beacon &&
+                    (!(wiphy->features & NL80211_FEATURE_AP_SCAN) ||
+                     !(req->flags & NL80211_SCAN_FLAG_AP)))
                         return -EOPNOTSUPP;
                 break;
         default:
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ba5a23249771..c42094be2f0b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -603,7 +603,9 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                            NL80211_FEATURE_HT_IBSS;
 
         if (!ops->hw_scan)
-                wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN;
+                wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN |
+                                   NL80211_FEATURE_AP_SCAN;
+
 
         if (!ops->set_key)
                 wiphy->flags |= WIPHY_FLAG_IBSS_RSN;