mac80211: Add HT rates into RX status reporting

This patch adds option for HT-enabled drivers to report HT rates
(HT20/HT40, short GI, MCS index) to mac80211. These rates are
currently not in the rate table, so the rate_idx is used to indicate
MCS index.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 61 insertions, 13 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 22ae72c58d76..9428d3e2f113 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -436,6 +436,9 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  *      is valid. This is useful in monitor mode and necessary for beacon frames
  *      to enable IBSS merging.
  * @RX_FLAG_SHORTPRE: Short preamble was used for this frame
+ * @RX_FLAG_HT: HT MCS was used and rate_idx is MCS index
+ * @RX_FLAG_40MHZ: HT40 (40 MHz) was used
+ * @RX_FLAG_SHORT_GI: Short guard interval was used
  */
 enum mac80211_rx_flags {
         RX_FLAG_MMIC_ERROR      = 1<<0,
@@ -446,7 +449,10 @@ enum mac80211_rx_flags {
         RX_FLAG_FAILED_FCS_CRC  = 1<<5,
         RX_FLAG_FAILED_PLCP_CRC = 1<<6,
         RX_FLAG_TSFT            = 1<<7,
-        RX_FLAG_SHORTPRE        = 1<<8
+        RX_FLAG_SHORTPRE        = 1<<8,
+        RX_FLAG_HT              = 1<<9,
+        RX_FLAG_40MHZ           = 1<<10,
+        RX_FLAG_SHORT_GI        = 1<<11,
 };
 
 /**
@@ -466,7 +472,8 @@ enum mac80211_rx_flags {
  * @noise: noise when receiving this frame, in dBm.
  * @qual: overall signal quality indication, in percent (0-100).
  * @antenna: antenna used
- * @rate_idx: index of data rate into band's supported rates
+ * @rate_idx: index of data rate into band's supported rates or MCS index if
+ *      HT rates are use (RX_FLAG_HT)
  * @flag: %RX_FLAG_*
  */
 struct ieee80211_rx_status {
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e4d1fca5c72d..a444b38f4901 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1613,8 +1613,13 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
                          * e.g: at 1 MBit that means mactime is 192 usec earlier
                          * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
                          */
-                        int rate = local->hw.wiphy->bands[band]->
+                        int rate;
+                        if (rx_status->flag & RX_FLAG_HT) {
+                                rate = 65; /* TODO: HT rates */
+                        } else {
+                                rate = local->hw.wiphy->bands[band]->
                                         bitrates[rx_status->rate_idx].bitrate;
+                        }
                         rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
                 } else if (local && local->ops && local->ops->get_tsf)
                         /* second best option: get current TSF */
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 73cf126cef49..b729c005a2b3 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -149,7 +149,17 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
         pos++;
 
         /* IEEE80211_RADIOTAP_RATE */
-        *pos = rate->bitrate / 5;
+        if (status->flag & RX_FLAG_HT) {
+                /*
+                 * TODO: add following information into radiotap header once
+                 * suitable fields are defined for it:
+                 * - MCS index (status->rate_idx)
+                 * - HT40 (status->flag & RX_FLAG_40MHZ)
+                 * - short-GI (status->flag & RX_FLAG_SHORT_GI)
+                 */
+                *pos = 0;
+        } else
+                *pos = rate->bitrate / 5;
         pos++;
 
         /* IEEE80211_RADIOTAP_CHANNEL */
@@ -1849,9 +1859,15 @@ static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
                         if (!(sdata->dev->flags & IFF_PROMISC))
                                 return 0;
                         rx->flags &= ~IEEE80211_RX_RA_MATCH;
-                } else if (!rx->sta)
+                } else if (!rx->sta) {
+                        int rate_idx;
+                        if (rx->status->flag & RX_FLAG_HT)
+                                rate_idx = 0; /* TODO: HT rates */
+                        else
+                                rate_idx = rx->status->rate_idx;
                         rx->sta = ieee80211_ibss_add_sta(sdata, bssid, hdr->addr2,
-                                BIT(rx->status->rate_idx));
+                                BIT(rate_idx));
+                }
                 break;
         case NL80211_IFTYPE_MESH_POINT:
                 if (!multicast &&
@@ -2057,7 +2073,13 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
                                         tid_agg_rx->reorder_buf[index]->cb,
                                         sizeof(status));
                                 sband = local->hw.wiphy->bands[status.band];
-                                rate = &sband->bitrates[status.rate_idx];
+                                if (status.flag & RX_FLAG_HT) {
+                                        /* TODO: HT rates */
+                                        rate = sband->bitrates;
+                                } else {
+                                        rate = &sband->bitrates
+                                                [status.rate_idx];
+                                }
                                 __ieee80211_rx_handle_packet(hw,
                                         tid_agg_rx->reorder_buf[index],
                                         &status, rate);
@@ -2101,7 +2123,10 @@ static u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw,
                 memcpy(&status, tid_agg_rx->reorder_buf[index]->cb,
                         sizeof(status));
                 sband = local->hw.wiphy->bands[status.band];
-                rate = &sband->bitrates[status.rate_idx];
+                if (status.flag & RX_FLAG_HT)
+                        rate = sband->bitrates; /* TODO: HT rates */
+                else
+                        rate = &sband->bitrates[status.rate_idx];
                 __ieee80211_rx_handle_packet(hw, tid_agg_rx->reorder_buf[index],
                                              &status, rate);
                 tid_agg_rx->stored_mpdu_num--;
@@ -2189,15 +2214,26 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb,
         }
 
         sband = local->hw.wiphy->bands[status->band];
-
-        if (!sband ||
-            status->rate_idx < 0 ||
-            status->rate_idx >= sband->n_bitrates) {
+        if (!sband) {
                 WARN_ON(1);
                 return;
         }
 
-        rate = &sband->bitrates[status->rate_idx];
+        if (status->flag & RX_FLAG_HT) {
+                /* rate_idx is MCS index */
+                if (WARN_ON(status->rate_idx < 0 ||
+                            status->rate_idx >= 76))
+                        return;
+                /* HT rates are not in the table - use the highest legacy rate
+                 * for now since other parts of mac80211 may not yet be fully
+                 * MCS aware. */
+                rate = &sband->bitrates[sband->n_bitrates - 1];
+        } else {
+                if (WARN_ON(status->rate_idx < 0 ||
+                            status->rate_idx >= sband->n_bitrates))
+                        return;
+                rate = &sband->bitrates[status->rate_idx];
+        }
 
         /*
          * key references and virtual interfaces are protected using RCU