mac80211: report some VHT radiotap infos for tx status

The radiotap VHT info is 12 bytes (required to be aligned on 2) :
u16 known - IEEE80211_RADIOTAP_VHT_KNOWN_*
u8 flags - IEEE80211_RADIOTAP_VHT_FLAG_*
u8 bandwidth
u8 mcs_nss[4]
u8 coding
u8 group_id
u16 partial_aid

ATM mac80211 can handle IEEE80211_RADIOTAP_VHT_KNOWN_{GI,BANDWIDTH} and
mcs_nss[0] (i.e single user) in simple cases.
This is more a placeholder to let sniffers give more clues for VHT,
since we don't have yet the proper infrastructure/conventions
in mac80211 for complete feedback (e.g consider dynamic BW).

Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 63 insertions, 13 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index 8eabfd96ca36..368837fe3b80 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -235,7 +235,8 @@ static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
 
         /* IEEE80211_RADIOTAP_RATE rate */
         if (info->status.rates[0].idx >= 0 &&
-            !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
+            !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
+                                             IEEE80211_TX_RC_VHT_MCS)))
                 len += 2;
 
         /* IEEE80211_RADIOTAP_TX_FLAGS */
@@ -244,16 +245,21 @@ static int ieee80211_tx_radiotap_len(struct ieee80211_tx_info *info)
         /* IEEE80211_RADIOTAP_DATA_RETRIES */
         len += 1;
 
-        /* IEEE80211_TX_RC_MCS */
-        if (info->status.rates[0].idx >= 0 &&
-            info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
-                len += 3;
+        /* IEEE80211_RADIOTAP_MCS
+         * IEEE80211_RADIOTAP_VHT */
+        if (info->status.rates[0].idx >= 0) {
+                if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS)
+                        len += 3;
+                else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS)
+                        len = ALIGN(len, 2) + 12;
+        }
 
         return len;
 }
 
 static void
-ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band *sband,
+ieee80211_add_tx_radiotap_header(struct ieee80211_local *local,
+                                 struct ieee80211_supported_band *sband,
                                  struct sk_buff *skb, int retry_count,
                                  int rtap_len, int shift)
 {
@@ -280,7 +286,8 @@ ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band *sband,
 
         /* IEEE80211_RADIOTAP_RATE */
         if (info->status.rates[0].idx >= 0 &&
-            !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS)) {
+            !(info->status.rates[0].flags & (IEEE80211_TX_RC_MCS |
+                                             IEEE80211_TX_RC_VHT_MCS))) {
                 u16 rate;
 
                 rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_RATE);
@@ -310,9 +317,12 @@ ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band *sband,
         *pos = retry_count;
         pos++;
 
-        /* IEEE80211_TX_RC_MCS */
-        if (info->status.rates[0].idx >= 0 &&
-            info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
+        if (info->status.rates[0].idx < 0)
+                return;
+
+        /* IEEE80211_RADIOTAP_MCS
+         * IEEE80211_RADIOTAP_VHT */
+        if (info->status.rates[0].flags & IEEE80211_TX_RC_MCS) {
                 rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_MCS);
                 pos[0] = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
                          IEEE80211_RADIOTAP_MCS_HAVE_GI |
@@ -325,8 +335,48 @@ ieee80211_add_tx_radiotap_header(struct ieee80211_supported_band *sband,
                         pos[1] |= IEEE80211_RADIOTAP_MCS_FMT_GF;
                 pos[2] = info->status.rates[0].idx;
                 pos += 3;
-        }
+        } else if (info->status.rates[0].flags & IEEE80211_TX_RC_VHT_MCS) {
+                u16 known = local->hw.radiotap_vht_details &
+                        (IEEE80211_RADIOTAP_VHT_KNOWN_GI |
+                         IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH);
+
+                rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
+
+                /* required alignment from rthdr */
+                pos = (u8 *)rthdr + ALIGN(pos - (u8 *)rthdr, 2);
 
+                /* u16 known - IEEE80211_RADIOTAP_VHT_KNOWN_* */
+                put_unaligned_le16(known, pos);
+                pos += 2;
+
+                /* u8 flags - IEEE80211_RADIOTAP_VHT_FLAG_* */
+                if (info->status.rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
+                        *pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
+                pos++;
+
+                /* u8 bandwidth */
+                if (info->status.rates[0].flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+                        *pos = 1;
+                else if (info->status.rates[0].flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
+                        *pos = 4;
+                else if (info->status.rates[0].flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
+                        *pos = 11;
+                else /* IEEE80211_TX_RC_{20_MHZ_WIDTH,FIXME:DUP_DATA} */
+                        *pos = 0;
+                pos++;
+
+                /* u8 mcs_nss[4] */
+                *pos = (ieee80211_rate_get_vht_mcs(&info->status.rates[0]) << 4) |
+                        ieee80211_rate_get_vht_nss(&info->status.rates[0]);
+                pos += 4;
+
+                /* u8 coding */
+                pos++;
+                /* u8 group_id */
+                pos++;
+                /* u16 partial_aid */
+                pos += 2;
+        }
 }
 
 static void ieee80211_report_used_skb(struct ieee80211_local *local,
@@ -631,8 +681,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                 dev_kfree_skb(skb);
                 return;
         }
-        ieee80211_add_tx_radiotap_header(sband, skb, retry_count, rtap_len,
-                                         shift);
+        ieee80211_add_tx_radiotap_header(local, sband, skb, retry_count,
+                                         rtap_len, shift);
 
         /* XXX: is this sufficient for BPF? */
         skb_set_mac_header(skb, 0);