mac80211: refactor station state transitions

Station entries can have various states, the most
important ones being auth, assoc and authorized.
This patch prepares us for telling the driver about
these states, we don't want to confuse drivers with
strange transitions, so with this we enforce that
they move in the right order between them (back and
forth); some transitions might happen before the
driver even knows about the station, but at least
runtime transitions will be ordered correctly.

As a consequence, IBSS and MESH stations will now
have the ASSOC flag set (so they can transition to
AUTHORIZED), and we can get rid of a special case
in TX processing.

When freeing a station, unwind the state so that
other parts of the code (or drivers later) can rely
on the transitions.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 1a14fab4bc9a..63f4d316a954 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -73,6 +73,14 @@ enum ieee80211_sta_info_flags {
         WLAN_STA_4ADDR_EVENT,
 };
 
+enum ieee80211_sta_state {
+        /* NOTE: These need to be ordered correctly! */
+        IEEE80211_STA_NONE,
+        IEEE80211_STA_AUTH,
+        IEEE80211_STA_ASSOC,
+        IEEE80211_STA_AUTHORIZED,
+};
+
 #define STA_TID_NUM 16
 #define ADDBA_RESP_INTERVAL HZ
 #define HT_AGG_MAX_RETRIES              0x3
@@ -262,6 +270,7 @@ struct sta_ampdu_mlme {
  * @dummy: indicate a dummy station created for receiving
  *      EAP frames before association
  * @sta: station information we share with the driver
+ * @sta_state: duplicates information about station state (for debug)
  */
 struct sta_info {
         /* General information, mostly static */
@@ -283,6 +292,8 @@ struct sta_info {
 
         bool uploaded;
 
+        enum ieee80211_sta_state sta_state;
+
         /* use the accessors defined below */
         unsigned long _flags;
 
@@ -371,12 +382,18 @@ static inline enum nl80211_plink_state sta_plink_state(struct sta_info *sta)
 static inline void set_sta_flag(struct sta_info *sta,
                                 enum ieee80211_sta_info_flags flag)
 {
+        WARN_ON(flag == WLAN_STA_AUTH ||
+                flag == WLAN_STA_ASSOC ||
+                flag == WLAN_STA_AUTHORIZED);
         set_bit(flag, &sta->_flags);
 }
 
 static inline void clear_sta_flag(struct sta_info *sta,
                                   enum ieee80211_sta_info_flags flag)
 {
+        WARN_ON(flag == WLAN_STA_AUTH ||
+                flag == WLAN_STA_ASSOC ||
+                flag == WLAN_STA_AUTHORIZED);
         clear_bit(flag, &sta->_flags);
 }
 
@@ -389,15 +406,32 @@ static inline int test_sta_flag(struct sta_info *sta,
 static inline int test_and_clear_sta_flag(struct sta_info *sta,
                                           enum ieee80211_sta_info_flags flag)
 {
+        WARN_ON(flag == WLAN_STA_AUTH ||
+                flag == WLAN_STA_ASSOC ||
+                flag == WLAN_STA_AUTHORIZED);
         return test_and_clear_bit(flag, &sta->_flags);
 }
 
 static inline int test_and_set_sta_flag(struct sta_info *sta,
                                         enum ieee80211_sta_info_flags flag)
 {
+        WARN_ON(flag == WLAN_STA_AUTH ||
+                flag == WLAN_STA_ASSOC ||
+                flag == WLAN_STA_AUTHORIZED);
         return test_and_set_bit(flag, &sta->_flags);
 }
 
+int sta_info_move_state_checked(struct sta_info *sta,
+                                enum ieee80211_sta_state new_state);
+
+static inline void sta_info_move_state(struct sta_info *sta,
+                                       enum ieee80211_sta_state new_state)
+{
+        int ret = sta_info_move_state_checked(sta, new_state);
+        WARN_ON_ONCE(ret);
+}
+
+
 void ieee80211_assign_tid_tx(struct sta_info *sta, int tid,
                              struct tid_ampdu_tx *tid_tx);
 
@@ -489,6 +523,9 @@ struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
  */
 struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
                                 u8 *addr, gfp_t gfp);
+
+void sta_info_free(struct ieee80211_local *local, struct sta_info *sta);
+
 /*
  * Insert STA info into hash table/list, returns zero or a
  * -EEXIST if (if the same MAC address is already present).