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>

1 files changed, 43 insertions, 0 deletions

diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index c22a71c..81d4ad6 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;