mac80211: retransmit TDLS teardown packet through AP if not ACKed

Since the TDLS peer station might not receive the teardown
packet (e.g., when in PS), this makes sure the packet is
retransmitted - this time through the AP - if the TDLS peer
didn't ACK the packet.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 48 insertions, 11 deletions

diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index b4f368e2cb3b..d4fe091fd98a 100644
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -512,20 +512,22 @@ ieee80211_tdls_prep_mgmt_packet(struct wiphy *wiphy, struct net_device *dev,
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	struct ieee80211_local *local = sdata->local;
 	struct sk_buff *skb = NULL;
+	u32 flags = 0;
 	bool send_direct;
 	struct sta_info *sta;
 	int ret;
 
-	skb = dev_alloc_skb(local->hw.extra_tx_headroom +
-			    max(sizeof(struct ieee80211_mgmt),
-				sizeof(struct ieee80211_tdls_data)) +
-			    50 + /* supported rates */
-			    7 + /* ext capab */
-			    26 + /* max(WMM-info, WMM-param) */
-			    2 + max(sizeof(struct ieee80211_ht_cap),
-				    sizeof(struct ieee80211_ht_operation)) +
-			    extra_ies_len +
-			    sizeof(struct ieee80211_tdls_lnkie));
+	skb = netdev_alloc_skb(dev,
+			       local->hw.extra_tx_headroom +
+			       max(sizeof(struct ieee80211_mgmt),
+				   sizeof(struct ieee80211_tdls_data)) +
+			       50 + /* supported rates */
+			       7 + /* ext capab */
+			       26 + /* max(WMM-info, WMM-param) */
+			       2 + max(sizeof(struct ieee80211_ht_cap),
+				       sizeof(struct ieee80211_ht_operation)) +
+			       extra_ies_len +
+			       sizeof(struct ieee80211_tdls_lnkie));
 	if (!skb)
 		return -ENOMEM;
 
@@ -623,9 +625,44 @@ ieee80211_tdls_prep_mgmt_packet(struct wiphy *wiphy, struct net_device *dev,
 		break;
 	}
 
+	/*
+	 * Set the WLAN_TDLS_TEARDOWN flag to indicate a teardown in progress.
+	 * Later, if no ACK is returned from peer, we will re-send the teardown
+	 * packet through the AP.
+	 */
+	if ((action_code == WLAN_TDLS_TEARDOWN) &&
+	    (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)) {
+		struct sta_info *sta = NULL;
+		bool try_resend; /* Should we keep skb for possible resend */
+
+		/* If not sending directly to peer - no point in keeping skb */
+		rcu_read_lock();
+		sta = sta_info_get(sdata, peer);
+		try_resend = sta && test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH);
+		rcu_read_unlock();
+
+		spin_lock_bh(&sdata->u.mgd.teardown_lock);
+		if (try_resend && !sdata->u.mgd.teardown_skb) {
+			/* Mark it as requiring TX status callback  */
+			flags |= IEEE80211_TX_CTL_REQ_TX_STATUS |
+				 IEEE80211_TX_INTFL_MLME_CONN_TX;
+
+			/*
+			 * skb is copied since mac80211 will later set
+			 * properties that might not be the same as the AP,
+			 * such as encryption, QoS, addresses, etc.
+			 *
+			 * No problem if skb_copy() fails, so no need to check.
+			 */
+			sdata->u.mgd.teardown_skb = skb_copy(skb, GFP_ATOMIC);
+			sdata->u.mgd.orig_teardown_skb = skb;
+		}
+		spin_unlock_bh(&sdata->u.mgd.teardown_lock);
+	}
+
 	/* disable bottom halves when entering the Tx path */
 	local_bh_disable();
-	ret = ieee80211_subif_start_xmit(skb, dev);
+	__ieee80211_subif_start_xmit(skb, dev, flags);
 	local_bh_enable();
 
 	return ret;