mac80211: support (partial) VHT radiotap information

Add some information that we have about VHT to radiotap.
This at least lets one see the MCS and NSS information.

Signed-off-by: Johannes Berg <[e-mail]>

include/net/ieee80211_radiotap.h

···
  * IEEE80211_RADIOTAP_AMPDU_STATUS	u32, u16, u8, u8	unitless
  *
  *	Contains the AMPDU information for the subframe.
+ *
+ * IEEE80211_RADIOTAP_VHT	u16, u8, u8, u8[4], u8, u8, u16
+ *
+ *	Contains VHT information about this frame.
  */
 enum ieee80211_radiotap_type {
 	IEEE80211_RADIOTAP_TSFT = 0,
···
 
 	IEEE80211_RADIOTAP_MCS = 19,
 	IEEE80211_RADIOTAP_AMPDU_STATUS = 20,
+	IEEE80211_RADIOTAP_VHT = 21,
 
 	/* valid in every it_present bitmap, even vendor namespaces */
 	IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
···
 #define IEEE80211_RADIOTAP_AMPDU_IS_LAST		0x0008
 #define IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR		0x0010
 #define IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN	0x0020
+
+/* For IEEE80211_RADIOTAP_VHT */
+#define IEEE80211_RADIOTAP_VHT_KNOWN_STBC			0x0001
+#define IEEE80211_RADIOTAP_VHT_KNOWN_TXOP_PS_NA			0x0002
+#define IEEE80211_RADIOTAP_VHT_KNOWN_GI				0x0004
+#define IEEE80211_RADIOTAP_VHT_KNOWN_SGI_NSYM_DIS		0x0008
+#define IEEE80211_RADIOTAP_VHT_KNOWN_LDPC_EXTRA_OFDM_SYM	0x0010
+#define IEEE80211_RADIOTAP_VHT_KNOWN_BEAMFORMED			0x0020
+#define IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH			0x0040
+#define IEEE80211_RADIOTAP_VHT_KNOWN_GROUP_ID			0x0080
+#define IEEE80211_RADIOTAP_VHT_KNOWN_PARTIAL_AID		0x0100
+
+#define IEEE80211_RADIOTAP_VHT_FLAG_STBC			0x01
+#define IEEE80211_RADIOTAP_VHT_FLAG_TXOP_PS_NA			0x02
+#define IEEE80211_RADIOTAP_VHT_FLAG_SGI				0x04
+#define IEEE80211_RADIOTAP_VHT_FLAG_SGI_NSYM_M10_9		0x08
+#define IEEE80211_RADIOTAP_VHT_FLAG_LDPC_EXTRA_OFDM_SYM		0x10
+#define IEEE80211_RADIOTAP_VHT_FLAG_BEAMFORMED			0x20
+
 
 /* helpers */
 static inline int ieee80211_get_radiotap_len(unsigned char *data)

include/net/mac80211.h

···
  *	include _FMT. Use %IEEE80211_RADIOTAP_MCS_HAVE_* values, only
  *	adding _BW is supported today.
  *
+ * @radiotap_vht_details: lists which VHT MCS information the HW reports,
+ *	the default is _GI | _BANDWIDTH.
+ *	Use the %IEEE80211_RADIOTAP_VHT_KNOWN_* values.
+ *
  * @netdev_features: netdev features to be set in each netdev created
  *	from this HW. Note only HW checksum features are currently
  *	compatible with mac80211. Other feature bits will be rejected.
···
 	u8 max_tx_aggregation_subframes;
 	u8 offchannel_tx_hw_queue;
 	u8 radiotap_mcs_details;
+	u16 radiotap_vht_details;
 	netdev_features_t netdev_features;
 };
 

net/mac80211/main.c

···
 	local->hw.radiotap_mcs_details = IEEE80211_RADIOTAP_MCS_HAVE_MCS |
 					 IEEE80211_RADIOTAP_MCS_HAVE_GI |
 					 IEEE80211_RADIOTAP_MCS_HAVE_BW;
+	local->hw.radiotap_vht_details = IEEE80211_RADIOTAP_VHT_KNOWN_GI |
+					 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
 	local->user_power_level = IEEE80211_UNSET_POWER_LEVEL;
 	wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;
 

net/mac80211/rx.c

···
 		len += 8;
 	}
 
+	if (status->flag & RX_FLAG_VHT) {
+		len = ALIGN(len, 2);
+		len += 12;
+	}
+
 	if (status->vendor_radiotap_len) {
 		if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
 			status->vendor_radiotap_align = 1;
···
 		else
 			*pos++ = 0;
 		*pos++ = 0;
+	}
+
+	if (status->flag & RX_FLAG_VHT) {
+		u16 known = local->hw.radiotap_vht_details;
+
+		rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_VHT);
+		/* known field - how to handle 80+80? */
+		if (status->flag & RX_FLAG_80P80MHZ)
+			known &= ~IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
+		put_unaligned_le16(known, pos);
+		pos += 2;
+		/* flags */
+		if (status->flag & RX_FLAG_SHORT_GI)
+			*pos |= IEEE80211_RADIOTAP_VHT_FLAG_SGI;
+		pos++;
+		/* bandwidth */
+		if (status->flag & RX_FLAG_80MHZ)
+			*pos++ = 4;
+		else if (status->flag & RX_FLAG_80P80MHZ)
+			*pos++ = 0; /* marked not known above */
+		else if (status->flag & RX_FLAG_160MHZ)
+			*pos++ = 11;
+		else if (status->flag & RX_FLAG_40MHZ)
+			*pos++ = 1;
+		else /* 20 MHz */
+			*pos++ = 0;
+		/* MCS/NSS */
+		*pos = (status->rate_idx << 4) | status->vht_nss;
+		pos += 4;
+		/* coding field */
+		pos++;
+		/* group ID */
+		pos++;
+		/* partial_aid */
+		pos += 2;
 	}
 
 	if (status->vendor_radiotap_len) {