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, 53 insertions, 2 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 9612d89fad56..71de2d3866cc 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -390,6 +390,46 @@ ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
         }
 }
 
+/*
+ * Handles the tx for TDLS teardown frames.
+ * If the frame wasn't ACKed by the peer - it will be re-sent through the AP
+ */
+static void ieee80211_tdls_td_tx_handle(struct ieee80211_local *local,
+                                        struct ieee80211_sub_if_data *sdata,
+                                        struct sk_buff *skb, u32 flags)
+{
+        struct sk_buff *teardown_skb;
+        struct sk_buff *orig_teardown_skb;
+        bool is_teardown = false;
+
+        /* Get the teardown data we need and free the lock */
+        spin_lock(&sdata->u.mgd.teardown_lock);
+        teardown_skb = sdata->u.mgd.teardown_skb;
+        orig_teardown_skb = sdata->u.mgd.orig_teardown_skb;
+        if ((skb == orig_teardown_skb) && teardown_skb) {
+                sdata->u.mgd.teardown_skb = NULL;
+                sdata->u.mgd.orig_teardown_skb = NULL;
+                is_teardown = true;
+        }
+        spin_unlock(&sdata->u.mgd.teardown_lock);
+
+        if (is_teardown) {
+                /* This mechanism relies on being able to get ACKs */
+                WARN_ON(!(local->hw.flags &
+                          IEEE80211_HW_REPORTS_TX_ACK_STATUS));
+
+                /* Check if peer has ACKed */
+                if (flags & IEEE80211_TX_STAT_ACK) {
+                        dev_kfree_skb_any(teardown_skb);
+                } else {
+                        tdls_dbg(sdata,
+                                 "TDLS Resending teardown through AP\n");
+
+                        ieee80211_subif_start_xmit(teardown_skb, skb->dev);
+                }
+        }
+}
+
 static void ieee80211_report_used_skb(struct ieee80211_local *local,
                                       struct sk_buff *skb, bool dropped)
 {
@@ -426,8 +466,19 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
                 if (!sdata) {
                         skb->dev = NULL;
                 } else if (info->flags & IEEE80211_TX_INTFL_MLME_CONN_TX) {
-                        ieee80211_mgd_conn_tx_status(sdata, hdr->frame_control,
-                                                     acked);
+                        unsigned int hdr_size =
+                                ieee80211_hdrlen(hdr->frame_control);
+
+                        /* Check to see if packet is a TDLS teardown packet */
+                        if (ieee80211_is_data(hdr->frame_control) &&
+                            (ieee80211_get_tdls_action(skb, hdr_size) ==
+                             WLAN_TDLS_TEARDOWN))
+                                ieee80211_tdls_td_tx_handle(local, sdata, skb,
+                                                            info->flags);
+                        else
+                                ieee80211_mgd_conn_tx_status(sdata,
+                                                             hdr->frame_control,
+                                                             acked);
                 } else if (ieee80211_is_nullfunc(hdr->frame_control) ||
                            ieee80211_is_qos_nullfunc(hdr->frame_control)) {
                         cfg80211_probe_status(sdata->dev, hdr->addr1,