mac80211: fix TX sequence numbers

This patch makes mac80211 assign proper sequence numbers to
QoS-data frames. It also removes the old sequence number code
because we noticed that only the driver or hardware can assign
sequence numbers to non-QoS-data and especially management
frames in a race-free manner because beacons aren't passed
through mac80211's TX path.

This patch also adds temporary code to the rt2x00 drivers to
not break them completely, that code will have to be reworked
for proper sequence numbers on beacons.

It also moves sequence number assignment down in the TX path
so no sequence numbers are assigned to frames that are dropped.

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

1 files changed, 51 insertions, 28 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 8843416e1460..0fbadd8b983c 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -38,16 +38,6 @@
 
 /* misc utils */
 
-static inline void ieee80211_include_sequence(struct ieee80211_sub_if_data *sdata,
-                                              struct ieee80211_hdr *hdr)
-{
-        /* Set the sequence number for this frame. */
-        hdr->seq_ctrl = cpu_to_le16(sdata->sequence);
-
-        /* Increase the sequence number. */
-        sdata->sequence = (sdata->sequence + 0x10) & IEEE80211_SCTL_SEQ;
-}
-
 #ifdef CONFIG_MAC80211_LOWTX_FRAME_DUMP
 static void ieee80211_dump_frame(const char *ifname, const char *title,
                                  const struct sk_buff *skb)
@@ -274,17 +264,6 @@ ieee80211_tx_h_check_assoc(struct ieee80211_tx_data *tx)
         return TX_CONTINUE;
 }
 
-static ieee80211_tx_result debug_noinline
-ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
-{
-        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
-
-        if (ieee80211_hdrlen(hdr->frame_control) >= 24)
-                ieee80211_include_sequence(tx->sdata, hdr);
-
-        return TX_CONTINUE;
-}
-
 /* This function is called whenever the AP is about to exceed the maximum limit
  * of buffered frames for power saving STAs. This situation should not really
  * happen often during normal operation, so dropping the oldest buffered packet
@@ -642,6 +621,49 @@ ieee80211_tx_h_misc(struct ieee80211_tx_data *tx)
 }
 
 static ieee80211_tx_result debug_noinline
+ieee80211_tx_h_sequence(struct ieee80211_tx_data *tx)
+{
+        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
+        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
+        u16 *seq;
+        u8 *qc;
+        int tid;
+
+        /* only for injected frames */
+        if (unlikely(ieee80211_is_ctl(hdr->frame_control)))
+                return TX_CONTINUE;
+
+        if (ieee80211_hdrlen(hdr->frame_control) < 24)
+                return TX_CONTINUE;
+
+        if (!ieee80211_is_data_qos(hdr->frame_control)) {
+                info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
+                return TX_CONTINUE;
+        }
+
+        /*
+         * This should be true for injected/management frames only, for
+         * management frames we have set the IEEE80211_TX_CTL_ASSIGN_SEQ
+         * above since they are not QoS-data frames.
+         */
+        if (!tx->sta)
+                return TX_CONTINUE;
+
+        /* include per-STA, per-TID sequence counter */
+
+        qc = ieee80211_get_qos_ctl(hdr);
+        tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
+        seq = &tx->sta->tid_seq[tid];
+
+        hdr->seq_ctrl = cpu_to_le16(*seq);
+
+        /* Increase the sequence number. */
+        *seq = (*seq + 0x10) & IEEE80211_SCTL_SEQ;
+
+        return TX_CONTINUE;
+}
+
+static ieee80211_tx_result debug_noinline
 ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
 {
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
@@ -1110,12 +1132,12 @@ static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
                 goto txh_done;
 
         CALL_TXH(ieee80211_tx_h_check_assoc)
-        CALL_TXH(ieee80211_tx_h_sequence)
         CALL_TXH(ieee80211_tx_h_ps_buf)
         CALL_TXH(ieee80211_tx_h_select_key)
         CALL_TXH(ieee80211_tx_h_michael_mic_add)
         CALL_TXH(ieee80211_tx_h_rate_ctrl)
         CALL_TXH(ieee80211_tx_h_misc)
+        CALL_TXH(ieee80211_tx_h_sequence)
         CALL_TXH(ieee80211_tx_h_fragment)
         /* handlers after fragment must be aware of tx info fragmentation! */
         CALL_TXH(ieee80211_tx_h_encrypt)
@@ -1827,9 +1849,6 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
                         memcpy(skb_put(skb, beacon->head_len), beacon->head,
                                beacon->head_len);
 
-                        ieee80211_include_sequence(sdata,
-                                        (struct ieee80211_hdr *)skb->data);
-
                         /*
                          * Not very nice, but we want to allow the driver to call
                          * ieee80211_beacon_get() as a response to the set_tim()
@@ -1919,14 +1938,18 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
 
         info->control.vif = vif;
         info->tx_rate_idx = rsel.rate_idx;
+
+        info->flags |= IEEE80211_TX_CTL_NO_ACK;
+        info->flags |= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;
+        info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
+        info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
         if (sdata->bss_conf.use_short_preamble &&
             sband->bitrates[rsel.rate_idx].flags & IEEE80211_RATE_SHORT_PREAMBLE)
                 info->flags |= IEEE80211_TX_CTL_SHORT_PREAMBLE;
+
         info->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
-        info->flags |= IEEE80211_TX_CTL_NO_ACK;
-        info->flags |= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;
         info->control.retry_limit = 1;
-        info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT;
+
         (*num_beacons)++;
 out:
         rcu_read_unlock();