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>
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 0e6277a..617d0fb 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3050,6 +3050,7 @@
* mode
* @NL80211_FEATURE_LOW_PRIORITY_SCAN: This driver supports low priority scan
* @NL80211_FEATURE_SCAN_FLUSH: Scan flush is supported
+ * @NL80211_FEATURE_AP_SCAN: Support scanning using an AP vif
*/
enum nl80211_feature_flags {
NL80211_FEATURE_SK_TX_STATUS = 1 << 0,
@@ -3060,6 +3061,7 @@
NL80211_FEATURE_SAE = 1 << 5,
NL80211_FEATURE_LOW_PRIORITY_SCAN = 1 << 6,
NL80211_FEATURE_SCAN_FLUSH = 1 << 7,
+ NL80211_FEATURE_AP_SCAN = 1 << 8,
};
/**
@@ -3103,10 +3105,16 @@
*
* @NL80211_SCAN_FLAG_LOW_PRIORITY: scan request has low priority
* @NL80211_SCAN_FLAG_FLUSH: flush cache before scanning
+ * @NL80211_SCAN_FLAG_AP: force a scan even if the interface is configured
+ * as AP and the beaconing has already been configured. This attribute is
+ * dangerous because will destroy stations performance as a lot of frames
+ * will be lost while scanning off-channel, therefore it must be used only
+ * when really needed
*/
enum nl80211_scan_flags {
NL80211_SCAN_FLAG_LOW_PRIORITY = 1<<0,
NL80211_SCAN_FLAG_FLUSH = 1<<1,
+ NL80211_SCAN_FLAG_AP = 1<<2,
};
#endif /* __LINUX_NL80211_H */
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 5739bfb..5eab132 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1855,7 +1855,16 @@
* 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 ba5a232..c42094b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -603,7 +603,9 @@
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;