carl9170: fix HT peer BA session corruption

This patch adds an alternative tx status path
for BlockAck Requests as the hardware doesn't
recognize that a BlockAck Requests is usually
acked with a BlockAck and not a legacy ACK.

Without this patch, the stack would constantly
resent old and stale BARs. So, depending on the
receiver stack, this could lead to:

 - "stuck" ba sessions and package loss, as the
   stale BAR would reset the sequence each time.

 - lots of reorder releases.

 - ...

Reported-by: Sean Patrick Santos <quantheory@gmail.com>
Reported-by: Mikołaj Kuligowski <mikolaj.q@wp.pl>
Reported-by: Per-Erik Westerberg <per-erik.westerberg@bredband.net>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
index 0cea20e..376be11 100644 (file)
--- a/drivers/net/wireless/ath/carl9170/carl9170.h
+++ b/drivers/net/wireless/ath/carl9170/carl9170.h
@@ -289,6 +289,7 @@ struct ar9170 {
                unsigned int mem_block_size;
                unsigned int rx_size;
                unsigned int tx_seq_table;
+               bool ba_filter;
        } fw;
 
        /* interface configuration combinations */
@@ -425,6 +426,10 @@ struct ar9170 {
        struct sk_buff *rx_failover;
        int rx_failover_missing;
 
+       /* FIFO for collecting outstanding BlockAckRequest */
+       struct list_head bar_list[__AR9170_NUM_TXQ];
+       spinlock_t bar_list_lock[__AR9170_NUM_TXQ];
+
 #ifdef CONFIG_CARL9170_WPC
        struct {
                bool pbc_state;
@@ -468,6 +473,12 @@ enum carl9170_ps_off_override_reasons {
        PS_OFF_BCN      = BIT(1),
 };
 
+struct carl9170_bar_list_entry {
+       struct list_head list;
+       struct rcu_head head;
+       struct sk_buff *skb;
+};
+
 struct carl9170_ba_stats {
        u8 ampdu_len;
        u8 ampdu_ack_len;

diff --git a/drivers/net/wireless/ath/carl9170/fw.c b/drivers/net/wireless/ath/carl9170/fw.c
index 5c73c03..c5ca6f1 100644 (file)
--- a/drivers/net/wireless/ath/carl9170/fw.c
+++ b/drivers/net/wireless/ath/carl9170/fw.c
@@ -307,6 +307,9 @@ static int carl9170_fw(struct ar9170 *ar, const __u8 *data, size_t len)
        if (SUPP(CARL9170FW_WOL))
                device_set_wakeup_enable(&ar->udev->dev, true);
 
+       if (SUPP(CARL9170FW_RX_BA_FILTER))
+               ar->fw.ba_filter = true;
+
        if_comb_types = BIT(NL80211_IFTYPE_STATION) |
                        BIT(NL80211_IFTYPE_P2P_CLIENT);
 

diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index 8d2523b..858e58d 100644 (file)
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -949,6 +949,9 @@ static void carl9170_op_configure_filter(struct ieee80211_hw *hw,
        if (ar->fw.rx_filter && changed_flags & ar->rx_filter_caps) {
                u32 rx_filter = 0;
 
+               if (!ar->fw.ba_filter)
+                       rx_filter |= CARL9170_RX_FILTER_CTL_OTHER;
+
                if (!(*new_flags & (FIF_FCSFAIL | FIF_PLCPFAIL)))
                        rx_filter |= CARL9170_RX_FILTER_BAD;
 
@@ -1753,6 +1756,9 @@ void *carl9170_alloc(size_t priv_size)
        for (i = 0; i < ar->hw->queues; i++) {
                skb_queue_head_init(&ar->tx_status[i]);
                skb_queue_head_init(&ar->tx_pending[i]);
+
+               INIT_LIST_HEAD(&ar->bar_list[i]);
+               spin_lock_init(&ar->bar_list_lock[i]);
        }
        INIT_WORK(&ar->ps_work, carl9170_ps_work);
        INIT_WORK(&ar->ping_work, carl9170_ping_work);

diff --git a/drivers/net/wireless/ath/carl9170/rx.c b/drivers/net/wireless/ath/carl9170/rx.c
index 84b22ee..25910a1 100644 (file)
--- a/drivers/net/wireless/ath/carl9170/rx.c
+++ b/drivers/net/wireless/ath/carl9170/rx.c
@@ -576,6 +576,53 @@ static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
        }
 }
 
+static void carl9170_ba_check(struct ar9170 *ar, void *data, unsigned int len)
+{
+       struct ieee80211_bar *bar = (void *) data;
+       struct carl9170_bar_list_entry *entry;
+       unsigned int queue;
+
+       if (likely(!ieee80211_is_back(bar->frame_control)))
+               return;
+
+       if (len <= sizeof(*bar) + FCS_LEN)
+               return;
+
+       queue = TID_TO_WME_AC(((le16_to_cpu(bar->control) &
+               IEEE80211_BAR_CTRL_TID_INFO_MASK) >>
+               IEEE80211_BAR_CTRL_TID_INFO_SHIFT) & 7);
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(entry, &ar->bar_list[queue], list) {
+               struct sk_buff *entry_skb = entry->skb;
+               struct _carl9170_tx_superframe *super = (void *)entry_skb->data;
+               struct ieee80211_bar *entry_bar = (void *)super->frame_data;
+
+#define TID_CHECK(a, b) (                                              \
+       ((a) & cpu_to_le16(IEEE80211_BAR_CTRL_TID_INFO_MASK)) ==        \
+       ((b) & cpu_to_le16(IEEE80211_BAR_CTRL_TID_INFO_MASK)))          \
+
+               if (bar->start_seq_num == entry_bar->start_seq_num &&
+                   TID_CHECK(bar->control, entry_bar->control) &&
+                   compare_ether_addr(bar->ra, entry_bar->ta) == 0 &&
+                   compare_ether_addr(bar->ta, entry_bar->ra) == 0) {
+                       struct ieee80211_tx_info *tx_info;
+
+                       tx_info = IEEE80211_SKB_CB(entry_skb);
+                       tx_info->flags |= IEEE80211_TX_STAT_ACK;
+
+                       spin_lock_bh(&ar->bar_list_lock[queue]);
+                       list_del_rcu(&entry->list);
+                       spin_unlock_bh(&ar->bar_list_lock[queue]);
+                       kfree_rcu(entry, head);
+                       break;
+               }
+       }
+       rcu_read_unlock();
+
+#undef TID_CHECK
+}
+
 static bool carl9170_ampdu_check(struct ar9170 *ar, u8 *buf, u8 ms)
 {
        __le16 fc;
@@ -738,6 +785,8 @@ static void carl9170_handle_mpdu(struct ar9170 *ar, u8 *buf, int len)
 
        carl9170_ps_beacon(ar, buf, mpdu_len);
 
+       carl9170_ba_check(ar, buf, mpdu_len);
+
        skb = carl9170_rx_copy_data(buf, mpdu_len);
        if (!skb)
                goto drop;

diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
index ede0b57..6a86814 100644 (file)
--- a/drivers/net/wireless/ath/carl9170/tx.c
+++ b/drivers/net/wireless/ath/carl9170/tx.c
@@ -436,6 +436,45 @@ out_rcu:
        rcu_read_unlock();
 }
 
+static void carl9170_tx_bar_status(struct ar9170 *ar, struct sk_buff *skb,
+       struct ieee80211_tx_info *tx_info)
+{
+       struct _carl9170_tx_superframe *super = (void *) skb->data;
+       struct ieee80211_bar *bar = (void *) super->frame_data;
+
+       /*
+        * Unlike all other frames, the status report for BARs does
+        * not directly come from the hardware as it is incapable of
+        * matching a BA to a previously send BAR.
+        * Instead the RX-path will scan for incoming BAs and set the
+        * IEEE80211_TX_STAT_ACK if it sees one that was likely
+        * caused by a BAR from us.
+        */
+
+       if (unlikely(ieee80211_is_back_req(bar->frame_control)) &&
+          !(tx_info->flags & IEEE80211_TX_STAT_ACK)) {
+               struct carl9170_bar_list_entry *entry;
+               int queue = skb_get_queue_mapping(skb);
+
+               rcu_read_lock();
+               list_for_each_entry_rcu(entry, &ar->bar_list[queue], list) {
+                       if (entry->skb == skb) {
+                               spin_lock_bh(&ar->bar_list_lock[queue]);
+                               list_del_rcu(&entry->list);
+                               spin_unlock_bh(&ar->bar_list_lock[queue]);
+                               kfree_rcu(entry, head);
+                               goto out;
+                       }
+               }
+
+               WARN(1, "bar not found in %d - ra:%pM ta:%pM c:%x ssn:%x\n",
+                      queue, bar->ra, bar->ta, bar->control,
+                       bar->start_seq_num);
+out:
+               rcu_read_unlock();
+       }
+}
+
 void carl9170_tx_status(struct ar9170 *ar, struct sk_buff *skb,
                        const bool success)
 {
@@ -445,6 +484,8 @@ void carl9170_tx_status(struct ar9170 *ar, struct sk_buff *skb,
 
        txinfo = IEEE80211_SKB_CB(skb);
 
+       carl9170_tx_bar_status(ar, skb, txinfo);
+
        if (success)
                txinfo->flags |= IEEE80211_TX_STAT_ACK;
        else
@@ -1265,6 +1306,26 @@ out_rcu:
        return false;
 }
 
+static void carl9170_bar_check(struct ar9170 *ar, struct sk_buff *skb)
+{
+       struct _carl9170_tx_superframe *super = (void *) skb->data;
+       struct ieee80211_bar *bar = (void *) super->frame_data;
+
+       if (unlikely(ieee80211_is_back_req(bar->frame_control)) &&
+           skb->len >= sizeof(struct ieee80211_bar)) {
+               struct carl9170_bar_list_entry *entry;
+               unsigned int queue = skb_get_queue_mapping(skb);
+
+               entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
+               if (!WARN_ON_ONCE(!entry)) {
+                       entry->skb = skb;
+                       spin_lock_bh(&ar->bar_list_lock[queue]);
+                       list_add_tail_rcu(&entry->list, &ar->bar_list[queue]);
+                       spin_unlock_bh(&ar->bar_list_lock[queue]);
+               }
+       }
+}
+
 static void carl9170_tx(struct ar9170 *ar)
 {
        struct sk_buff *skb;
@@ -1287,6 +1348,8 @@ static void carl9170_tx(struct ar9170 *ar)
                        if (unlikely(carl9170_tx_ps_drop(ar, skb)))
                                continue;
 
+                       carl9170_bar_check(ar, skb);
+
                        atomic_inc(&ar->tx_total_pending);
 
                        q = __carl9170_get_queue(ar, i);