mac80211: allow drivers to request DTIM period

Some features require knowing the DTIM period
before associating. This implements the ability
to wait for a beacon in mac80211 before assoc
to provide this value. It is optional since
most likely not all drivers will need this.

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

5 files changed, 84 insertions, 5 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c7027ef51c75..f85fc8a140dc 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -194,7 +194,9 @@ enum ieee80211_bss_change {
  *      if the hardware cannot handle this it must set the
  *      IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE hardware flag
  * @dtim_period: num of beacons before the next DTIM, for beaconing,
- *      not valid in station mode (cf. hw conf ps_dtim_period)
+ *      valid in station mode only while @assoc is true and if also
+ *      requested by %IEEE80211_HW_NEED_DTIM_PERIOD (cf. also hw conf
+ *      @ps_dtim_period)
  * @timestamp: beacon timestamp
  * @beacon_int: beacon interval
  * @assoc_capability: capabilities taken from assoc resp
@@ -1027,6 +1029,9 @@ enum ieee80211_tkip_key_type {
  *      connection quality related parameters, such as the RSSI level and
  *      provide notifications if configured trigger levels are reached.
  *
+ * @IEEE80211_HW_NEED_DTIM_PERIOD:
+ *      This device needs to know the DTIM period for the BSS before
+ *      associating.
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
@@ -1036,7 +1041,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_2GHZ_SHORT_PREAMBLE_INCAPABLE      = 1<<4,
         IEEE80211_HW_SIGNAL_UNSPEC                      = 1<<5,
         IEEE80211_HW_SIGNAL_DBM                         = 1<<6,
-        /* use this hole */
+        IEEE80211_HW_NEED_DTIM_PERIOD                   = 1<<7,
         IEEE80211_HW_SPECTRUM_MGMT                      = 1<<8,
         IEEE80211_HW_AMPDU_AGGREGATION                  = 1<<9,
         IEEE80211_HW_SUPPORTS_PS                        = 1<<10,
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index ef470064b154..65e0ed6c2975 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -238,6 +238,7 @@ enum ieee80211_work_type {
         IEEE80211_WORK_ABORT,
         IEEE80211_WORK_DIRECT_PROBE,
         IEEE80211_WORK_AUTH,
+        IEEE80211_WORK_ASSOC_BEACON_WAIT,
         IEEE80211_WORK_ASSOC,
         IEEE80211_WORK_REMAIN_ON_CHANNEL,
 };
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index cf8d72196c65..b6c163ac22da 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -870,6 +870,11 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
 
         ieee80211_led_assoc(local, 1);
 
+        if (local->hw.flags & IEEE80211_HW_NEED_DTIM_PERIOD)
+                bss_conf->dtim_period = bss->dtim_period;
+        else
+                bss_conf->dtim_period = 0;
+
         bss_conf->assoc = 1;
         /*
          * For now just always ask the driver to update the basic rateset
@@ -1751,7 +1756,8 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
                         if (wk->sdata != sdata)
                                 continue;
 
-                        if (wk->type != IEEE80211_WORK_ASSOC)
+                        if (wk->type != IEEE80211_WORK_ASSOC &&
+                            wk->type != IEEE80211_WORK_ASSOC_BEACON_WAIT)
                                 continue;
 
                         if (memcmp(mgmt->bssid, wk->filter_ta, ETH_ALEN))
@@ -2086,6 +2092,8 @@ static enum work_done_result ieee80211_assoc_done(struct ieee80211_work *wk,
                                                   struct sk_buff *skb)
 {
         struct ieee80211_mgmt *mgmt;
+        struct ieee80211_rx_status *rx_status;
+        struct ieee802_11_elems elems;
         u16 status;
 
         if (!skb) {
@@ -2093,6 +2101,19 @@ static enum work_done_result ieee80211_assoc_done(struct ieee80211_work *wk,
                 return WORK_DONE_DESTROY;
         }
 
+        if (wk->type == IEEE80211_WORK_ASSOC_BEACON_WAIT) {
+                mutex_lock(&wk->sdata->u.mgd.mtx);
+                rx_status = (void *) skb->cb;
+                ieee802_11_parse_elems(skb->data + 24 + 12, skb->len - 24 - 12, &elems);
+                ieee80211_rx_bss_info(wk->sdata, (void *)skb->data, skb->len, rx_status,
+                                      &elems, true);
+                mutex_unlock(&wk->sdata->u.mgd.mtx);
+
+                wk->type = IEEE80211_WORK_ASSOC;
+                /* not really done yet */
+                return WORK_DONE_REQUEUE;
+        }
+
         mgmt = (void *)skb->data;
         status = le16_to_cpu(mgmt->u.assoc_resp.status_code);
 
@@ -2206,10 +2227,14 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
         if (req->prev_bssid)
                 memcpy(wk->assoc.prev_bssid, req->prev_bssid, ETH_ALEN);
 
-        wk->type = IEEE80211_WORK_ASSOC;
         wk->chan = req->bss->channel;
         wk->sdata = sdata;
         wk->done = ieee80211_assoc_done;
+        if (!bss->dtim_period &&
+            sdata->local->hw.flags & IEEE80211_HW_NEED_DTIM_PERIOD)
+                wk->type = IEEE80211_WORK_ASSOC_BEACON_WAIT;
+        else
+                wk->type = IEEE80211_WORK_ASSOC;
 
         if (req->use_mfp) {
                 ifmgd->mfp = IEEE80211_MFP_REQUIRED;
@@ -2257,7 +2282,8 @@ int ieee80211_mgd_deauth(struct ieee80211_sub_if_data *sdata,
 
                         if (wk->type != IEEE80211_WORK_DIRECT_PROBE &&
                             wk->type != IEEE80211_WORK_AUTH &&
-                            wk->type != IEEE80211_WORK_ASSOC)
+                            wk->type != IEEE80211_WORK_ASSOC &&
+                            wk->type != IEEE80211_WORK_ASSOC_BEACON_WAIT)
                                 continue;
 
                         if (memcmp(req->bss->bssid, wk->filter_ta, ETH_ALEN))
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 41635b2c91bf..41f20fb7e670 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -114,6 +114,10 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
                 bss->dtim_period = tim_ie->dtim_period;
         }
 
+        /* If the beacon had no TIM IE, or it was invalid, use 1 */
+        if (beacon && !bss->dtim_period)
+                bss->dtim_period = 1;
+
         /* replace old supported rates if we get new values */
         srlen = 0;
         if (elems->supp_rates) {
diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index c22a71c5cb45..81d4ad64184a 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -560,6 +560,22 @@ ieee80211_remain_on_channel_timeout(struct ieee80211_work *wk)
         return WORK_ACT_TIMEOUT;
 }
 
+static enum work_action __must_check
+ieee80211_assoc_beacon_wait(struct ieee80211_work *wk)
+{
+        if (wk->started)
+                return WORK_ACT_TIMEOUT;
+
+        /*
+         * Wait up to one beacon interval ...
+         * should this be more if we miss one?
+         */
+        printk(KERN_DEBUG "%s: waiting for beacon from %pM\n",
+               wk->sdata->name, wk->filter_ta);
+        wk->timeout = TU_TO_EXP_TIME(wk->assoc.bss->beacon_interval);
+        return WORK_ACT_NONE;
+}
+
 static void ieee80211_auth_challenge(struct ieee80211_work *wk,
                                      struct ieee80211_mgmt *mgmt,
                                      size_t len)
@@ -709,6 +725,25 @@ ieee80211_rx_mgmt_probe_resp(struct ieee80211_work *wk,
         return WORK_ACT_DONE;
 }
 
+static enum work_action __must_check
+ieee80211_rx_mgmt_beacon(struct ieee80211_work *wk,
+                         struct ieee80211_mgmt *mgmt, size_t len)
+{
+        struct ieee80211_sub_if_data *sdata = wk->sdata;
+        struct ieee80211_local *local = sdata->local;
+
+        ASSERT_WORK_MTX(local);
+
+        if (wk->type != IEEE80211_WORK_ASSOC_BEACON_WAIT)
+                return WORK_ACT_MISMATCH;
+
+        if (len < 24 + 12)
+                return WORK_ACT_NONE;
+
+        printk(KERN_DEBUG "%s: beacon received\n", sdata->name);
+        return WORK_ACT_DONE;
+}
+
 static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
                                           struct sk_buff *skb)
 {
@@ -731,6 +766,7 @@ static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
                 case IEEE80211_WORK_DIRECT_PROBE:
                 case IEEE80211_WORK_AUTH:
                 case IEEE80211_WORK_ASSOC:
+                case IEEE80211_WORK_ASSOC_BEACON_WAIT:
                         bssid = wk->filter_ta;
                         break;
                 default:
@@ -745,6 +781,9 @@ static void ieee80211_work_rx_queued_mgmt(struct ieee80211_local *local,
                         continue;
 
                 switch (fc & IEEE80211_FCTL_STYPE) {
+                case IEEE80211_STYPE_BEACON:
+                        rma = ieee80211_rx_mgmt_beacon(wk, mgmt, skb->len);
+                        break;
                 case IEEE80211_STYPE_PROBE_RESP:
                         rma = ieee80211_rx_mgmt_probe_resp(wk, mgmt, skb->len,
                                                            rx_status);
@@ -916,6 +955,9 @@ static void ieee80211_work_work(struct work_struct *work)
                 case IEEE80211_WORK_REMAIN_ON_CHANNEL:
                         rma = ieee80211_remain_on_channel_timeout(wk);
                         break;
+                case IEEE80211_WORK_ASSOC_BEACON_WAIT:
+                        rma = ieee80211_assoc_beacon_wait(wk);
+                        break;
                 }
 
                 wk->started = started;
@@ -1065,6 +1107,7 @@ ieee80211_rx_result ieee80211_work_rx_mgmt(struct ieee80211_sub_if_data *sdata,
                 case IEEE80211_STYPE_PROBE_RESP:
                 case IEEE80211_STYPE_ASSOC_RESP:
                 case IEEE80211_STYPE_REASSOC_RESP:
+                case IEEE80211_STYPE_BEACON:
                         skb_queue_tail(&local->work_skb_queue, skb);
                         ieee80211_queue_work(&local->hw, &local->work_work);
                         return RX_QUEUED;