[PATCH] softmac: ERP handling and driver-level notifications

This patch implements ERP handling in softmac so that the drivers can support
protection and preambles properly.

I added a new struct, ieee80211softmac_bss_info, which is used for
BSS-dependent variables like these.

A new hook has been added (bssinfo_change), which allows the drivers to be
notified when anything in bssinfo changes.

I modified the txrates_change API to match the bssinfo_change API. The
existing one is a little messy and the usefulness of providing the old rates
is questionable (and can be implemented at driver level if really necessary).
No drivers are using this API (yet), so this should be safe.

Signed-off-by: Daniel Drake <dsd@gentoo.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 46 insertions, 6 deletions

diff --git a/include/net/ieee80211softmac.h b/include/net/ieee80211softmac.h
index 00ad810eb883..c27d03433c21 100644
--- a/include/net/ieee80211softmac.h
+++ b/include/net/ieee80211softmac.h
@@ -86,9 +86,6 @@ struct ieee80211softmac_assoc_info {
         
         /* BSSID we're trying to associate to */
         char bssid[ETH_ALEN];
-
-        /* Rates supported by the network */
-        struct ieee80211softmac_ratesinfo supported_rates;
         
         /* some flags.
          * static_essid is valid if the essid is constant,
@@ -103,6 +100,7 @@ struct ieee80211softmac_assoc_info {
          * bssfixed is used for SIOCSIWAP.
          */
         u8 static_essid:1,
+           short_preamble_available:1,
            associating:1,
            assoc_wait:1,
            bssvalid:1,
@@ -115,6 +113,19 @@ struct ieee80211softmac_assoc_info {
         struct work_struct timeout;
 };
 
+struct ieee80211softmac_bss_info {
+        /* Rates supported by the network */
+        struct ieee80211softmac_ratesinfo supported_rates;
+
+        /* This indicates whether frames can currently be transmitted with
+         * short preamble (only use this variable during TX at CCK rates) */
+        u8 short_preamble:1;
+
+        /* This indicates whether protection (e.g. self-CTS) should be used
+         * when transmitting with OFDM modulation */
+        u8 use_protection:1;
+};
+
 enum {
         IEEE80211SOFTMAC_AUTH_OPEN_REQUEST      = 1,
         IEEE80211SOFTMAC_AUTH_OPEN_RESPONSE     = 2,
@@ -157,6 +168,10 @@ struct ieee80211softmac_txrates {
 #define IEEE80211SOFTMAC_TXRATECHG_MCAST                (1 << 2) /* mcast_rate */
 #define IEEE80211SOFTMAC_TXRATECHG_MGT_MCAST            (1 << 3) /* mgt_mcast_rate */
 
+#define IEEE80211SOFTMAC_BSSINFOCHG_RATES               (1 << 0) /* supported_rates */
+#define IEEE80211SOFTMAC_BSSINFOCHG_SHORT_PREAMBLE      (1 << 1) /* short_preamble */
+#define IEEE80211SOFTMAC_BSSINFOCHG_PROTECTION          (1 << 2) /* use_protection */
+
 struct ieee80211softmac_device {
         /* 802.11 structure for data stuff */
         struct ieee80211_device *ieee;
@@ -200,10 +215,16 @@ struct ieee80211softmac_device {
          * The driver just needs to read them.
          */
         struct ieee80211softmac_txrates txrates;
-        /* If the driver needs to do stuff on TX rate changes, assign this callback. */
+
+        /* If the driver needs to do stuff on TX rate changes, assign this
+         * callback. See IEEE80211SOFTMAC_TXRATECHG for change flags. */
         void (*txrates_change)(struct net_device *dev,
-                               u32 changes, /* see IEEE80211SOFTMAC_TXRATECHG flags */
-                               const struct ieee80211softmac_txrates *rates_before_change);
+                               u32 changes);
+
+        /* If the driver needs to do stuff when BSS properties change, assign
+         * this callback. see IEEE80211SOFTMAC_BSSINFOCHG for change flags. */
+        void (*bssinfo_change)(struct net_device *dev,
+                               u32 changes);
 
         /* private stuff follows */
         /* this lock protects this structure */
@@ -216,6 +237,7 @@ struct ieee80211softmac_device {
         
         struct ieee80211softmac_scaninfo *scaninfo;
         struct ieee80211softmac_assoc_info associnfo;
+        struct ieee80211softmac_bss_info bssinfo;
 
         struct list_head auth_queue;
         struct list_head events;
@@ -279,6 +301,24 @@ static inline u8 ieee80211softmac_suggest_txrate(struct ieee80211softmac_device
                 return txrates->mcast_rate;
 }
 
+/* Helper function which advises you when it is safe to transmit with short
+ * preamble.
+ * You should only call this function when transmitting at CCK rates. */
+static inline int ieee80211softmac_short_preamble_ok(struct ieee80211softmac_device *mac,
+                                                    int is_multicast,
+                                                    int is_mgt)
+{
+        return (is_multicast && is_mgt) ? 0 : mac->bssinfo.short_preamble;
+}
+
+/* Helper function which advises you whether protection (e.g. self-CTS) is
+ * needed. 1 = protection needed, 0 = no protection needed
+ * Only use this function when transmitting with OFDM modulation. */
+static inline int ieee80211softmac_protection_needed(struct ieee80211softmac_device *mac)
+{
+        return mac->bssinfo.use_protection;
+}
+
 /* Start the SoftMAC. Call this after you initialized the device
  * and it is ready to run.
  */