mac80211: implement wifi TX status

Implement the socket wifi TX status error
queue reflection in mac80211.

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

5 files changed, 115 insertions, 6 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index b9b9c9452131..2714646b298f 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -518,7 +518,7 @@ struct ieee80211_tx_rate {
  * @flags: transmit info flags, defined above
  * @band: the band to transmit on (use for checking for races)
  * @antenna_sel_tx: antenna to use, 0 for automatic diversity
- * @pad: padding, ignore
+ * @ack_frame_id: internal frame ID for TX status, used internally
  * @control: union for control data
  * @status: union for status data
  * @driver_data: array of driver_data pointers
@@ -535,8 +535,7 @@ struct ieee80211_tx_info {
 
         u8 antenna_sel_tx;
 
-        /* 2 byte hole */
-        u8 pad[2];
+        u16 ack_frame_id;
 
         union {
                 struct {
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4bef6eca1722..76e656bf78f9 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -24,6 +24,7 @@
 #include <linux/spinlock.h>
 #include <linux/etherdevice.h>
 #include <linux/leds.h>
+#include <linux/idr.h>
 #include <net/ieee80211_radiotap.h>
 #include <net/cfg80211.h>
 #include <net/mac80211.h>
@@ -1017,6 +1018,9 @@ struct ieee80211_local {
         u32 hw_roc_cookie;
         bool hw_roc_for_tx;
 
+        struct idr ack_status_frames;
+        spinlock_t ack_status_lock;
+
         /* dummy netdev for use w/ NAPI */
         struct net_device napi_dev;
 
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 8e9327bca910..e323d4e6647b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -596,6 +596,8 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                         WIPHY_FLAG_4ADDR_STATION |
                         WIPHY_FLAG_REPORTS_OBSS;
 
+        wiphy->features = NL80211_FEATURE_SK_TX_STATUS;
+
         if (!ops->set_key)
                 wiphy->flags |= WIPHY_FLAG_IBSS_RSN;
 
@@ -669,6 +671,11 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
         INIT_WORK(&local->sched_scan_stopped_work,
                   ieee80211_sched_scan_stopped_work);
 
+        spin_lock_init(&local->ack_status_lock);
+        idr_init(&local->ack_status_frames);
+        /* preallocate at least one entry */
+        idr_pre_get(&local->ack_status_frames, GFP_KERNEL);
+
         sta_info_init(local);
 
         for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
@@ -1044,6 +1051,13 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 }
 EXPORT_SYMBOL(ieee80211_unregister_hw);
 
+static int ieee80211_free_ack_frame(int id, void *p, void *data)
+{
+        WARN_ONCE(1, "Have pending ack frames!\n");
+        kfree_skb(p);
+        return 0;
+}
+
 void ieee80211_free_hw(struct ieee80211_hw *hw)
 {
         struct ieee80211_local *local = hw_to_local(hw);
@@ -1054,6 +1068,10 @@ void ieee80211_free_hw(struct ieee80211_hw *hw)
         if (local->wiphy_ciphers_allocated)
                 kfree(local->hw.wiphy->cipher_suites);
 
+        idr_for_each(&local->ack_status_frames,
+                     ieee80211_free_ack_frame, NULL);
+        idr_destroy(&local->ack_status_frames);
+
         wiphy_free(local->hw.wiphy);
 }
 EXPORT_SYMBOL(ieee80211_free_hw);
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 94702f103cfc..83b800d17a9a 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -548,6 +548,24 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                 }
         }
 
+        if (unlikely(info->ack_frame_id)) {
+                struct sk_buff *ack_skb;
+                unsigned long flags;
+
+                spin_lock_irqsave(&local->ack_status_lock, flags);
+                ack_skb = idr_find(&local->ack_status_frames,
+                                   info->ack_frame_id);
+                if (ack_skb)
+                        idr_remove(&local->ack_status_frames,
+                                   info->ack_frame_id);
+                spin_unlock_irqrestore(&local->ack_status_lock, flags);
+
+                /* consumes ack_skb */
+                if (ack_skb)
+                        skb_complete_wifi_ack(ack_skb,
+                                info->flags & IEEE80211_TX_STAT_ACK);
+        }
+
         /* this was a transmitted frame, but now we want to reuse it */
         skb_orphan(skb);
 
@@ -621,6 +639,26 @@ EXPORT_SYMBOL(ieee80211_report_low_ack);
 
 void ieee80211_free_txskb(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
+        struct ieee80211_local *local = hw_to_local(hw);
+        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+        if (unlikely(info->ack_frame_id)) {
+                struct sk_buff *ack_skb;
+                unsigned long flags;
+
+                spin_lock_irqsave(&local->ack_status_lock, flags);
+                ack_skb = idr_find(&local->ack_status_frames,
+                                   info->ack_frame_id);
+                if (ack_skb)
+                        idr_remove(&local->ack_status_frames,
+                                   info->ack_frame_id);
+                spin_unlock_irqrestore(&local->ack_status_lock, flags);
+
+                /* consumes ack_skb */
+                if (ack_skb)
+                        dev_kfree_skb_any(ack_skb);
+        }
+
         dev_kfree_skb_any(skb);
 }
 EXPORT_SYMBOL(ieee80211_free_txskb);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a543d26058db..ab6cb56bc74d 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1684,8 +1684,10 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
         int nh_pos, h_pos;
         struct sta_info *sta = NULL;
         bool wme_sta = false, authorized = false, tdls_auth = false;
-        struct sk_buff *tmp_skb;
         bool tdls_direct = false;
+        bool multicast;
+        u32 info_flags = 0;
+        u16 info_id = 0;
 
         if (unlikely(skb->len < ETH_HLEN)) {
                 ret = NETDEV_TX_OK;
@@ -1872,7 +1874,8 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
          * if it is a multicast address (which can only happen
          * in AP mode)
          */
-        if (!is_multicast_ether_addr(hdr.addr1)) {
+        multicast = is_multicast_ether_addr(hdr.addr1);
+        if (!multicast) {
                 rcu_read_lock();
                 sta = sta_info_get(sdata, hdr.addr1);
                 if (sta) {
@@ -1913,11 +1916,54 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
                 goto fail;
         }
 
+        if (unlikely(!multicast && skb->sk &&
+                     skb_shinfo(skb)->tx_flags & SKBTX_WIFI_STATUS)) {
+                struct sk_buff *orig_skb = skb;
+
+                skb = skb_clone(skb, GFP_ATOMIC);
+                if (skb) {
+                        unsigned long flags;
+                        int id, r;
+
+                        spin_lock_irqsave(&local->ack_status_lock, flags);
+                        r = idr_get_new_above(&local->ack_status_frames,
+                                              orig_skb, 1, &id);
+                        if (r == -EAGAIN) {
+                                idr_pre_get(&local->ack_status_frames,
+                                            GFP_ATOMIC);
+                                r = idr_get_new_above(&local->ack_status_frames,
+                                                      orig_skb, 1, &id);
+                        }
+                        if (WARN_ON(!id) || id > 0xffff) {
+                                idr_remove(&local->ack_status_frames, id);
+                                r = -ERANGE;
+                        }
+                        spin_unlock_irqrestore(&local->ack_status_lock, flags);
+
+                        if (!r) {
+                                info_id = id;
+                                info_flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
+                        } else if (skb_shared(skb)) {
+                                kfree_skb(orig_skb);
+                        } else {
+                                kfree_skb(skb);
+                                skb = orig_skb;
+                        }
+                } else {
+                        /* couldn't clone -- lose tx status ... */
+                        skb = orig_skb;
+                }
+        }
+
         /*
          * If the skb is shared we need to obtain our own copy.
          */
         if (skb_shared(skb)) {
-                tmp_skb = skb;
+                struct sk_buff *tmp_skb = skb;
+
+                /* can't happen -- skb is a clone if info_id != 0 */
+                WARN_ON(info_id);
+
                 skb = skb_clone(skb, GFP_ATOMIC);
                 kfree_skb(tmp_skb);
 
@@ -2018,6 +2064,10 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
         memset(info, 0, sizeof(*info));
 
         dev->trans_start = jiffies;
+
+        info->flags = info_flags;
+        info->ack_frame_id = info_id;
+
         ieee80211_xmit(sdata, skb);
 
         return NETDEV_TX_OK;