nl80211/mac80211: support full station state in AP mode

Today, stations are added already associated. That is
inefficient if, for example, the driver has no room
for stations any more because then the station will
go through the entire auth/assoc handshake, only to
be kicked out afterwards.

To address this a bit better, at least with drivers
using the new station state callback, allow hostapd
to add stations in unauthenticated mode, just after
receiving the AUTH frame, before even replying. Thus
if there's no more space at that point, it can send
a negative auth frame back. It still needs to handle
later state transition errors though, of course.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index e3e19f8b16f2..547017100a30 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1697,6 +1697,9 @@ enum nl80211_iftype {
  *      flag can't be changed, it is only valid while adding a station, and
  *      attempts to change it will silently be ignored (rather than rejected
  *      as errors.)
+ * @NL80211_STA_FLAG_ASSOCIATED: station is associated; used with drivers
+ *      that support %NL80211_FEATURE_FULL_AP_CLIENT_STATE to transition a
+ *      previously added station into associated state
  * @NL80211_STA_FLAG_MAX: highest station flag number currently defined
  * @__NL80211_STA_FLAG_AFTER_LAST: internal use
  */
@@ -1708,6 +1711,7 @@ enum nl80211_sta_flags {
         NL80211_STA_FLAG_MFP,
         NL80211_STA_FLAG_AUTHENTICATED,
         NL80211_STA_FLAG_TDLS_PEER,
+        NL80211_STA_FLAG_ASSOCIATED,
 
         /* keep last */
         __NL80211_STA_FLAG_AFTER_LAST,
@@ -3140,6 +3144,17 @@ enum nl80211_ap_sme_features {
  *      setting
  * @NL80211_FEATURE_P2P_GO_OPPPS: P2P GO implementation supports opportunistic
  *      powersave
+ * @NL80211_FEATURE_FULL_AP_CLIENT_STATE: The driver supports full state
+ *      transitions for AP clients. Without this flag (and if the driver
+ *      doesn't have the AP SME in the device) the driver supports adding
+ *      stations only when they're associated and adds them in associated
+ *      state (to later be transitioned into authorized), with this flag
+ *      they should be added before even sending the authentication reply
+ *      and then transitioned into authenticated, associated and authorized
+ *      states using station flags.
+ *      Note that even for drivers that support this, the default is to add
+ *      stations in authenticated/associated state, so to add unauthenticated
+ *      stations the authenticated/associated bits have to be set in the mask.
  */
 enum nl80211_feature_flags {
         NL80211_FEATURE_SK_TX_STATUS                    = 1 << 0,
@@ -3155,6 +3170,7 @@ enum nl80211_feature_flags {
         NL80211_FEATURE_NEED_OBSS_SCAN                  = 1 << 10,
         NL80211_FEATURE_P2P_GO_CTWIN                    = 1 << 11,
         NL80211_FEATURE_P2P_GO_OPPPS                    = 1 << 12,
+        NL80211_FEATURE_FULL_AP_CLIENT_STATE            = 1 << 13,
 };
 
 /**