mac80211: add back support for radiotap vendor namespace data

Radiotap vendor namespace data might still be useful, but we
reverted it because it used too much space in the RX status.
Put it back, but address the space problem by using a single
bit only and putting everything else into the skb->data.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 5f203a6a5e7..83232aa2f07 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -882,6 +882,9 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  *	subframes share the same sequence number. Reported subframes can be
  *	either regular MSDU or singly A-MSDUs. Subframes must not be
  *	interleaved with other frames.
+ * @RX_FLAG_RADIOTAP_VENDOR_DATA: This frame contains vendor-specific
+ *	radiotap data in the skb->data (before the frame) as described by
+ *	the &struct ieee80211_vendor_radiotap.
  */
 enum mac80211_rx_flags {
 	RX_FLAG_MMIC_ERROR		= BIT(0),
@@ -911,6 +914,7 @@ enum mac80211_rx_flags {
 	RX_FLAG_10MHZ			= BIT(28),
 	RX_FLAG_5MHZ			= BIT(29),
 	RX_FLAG_AMSDU_MORE		= BIT(30),
+	RX_FLAG_RADIOTAP_VENDOR_DATA	= BIT(31),
 };
 
 #define RX_FLAG_STBC_SHIFT		26
@@ -982,6 +986,39 @@ struct ieee80211_rx_status {
 };
 
 /**
+ * struct ieee80211_vendor_radiotap - vendor radiotap data information
+ * @present: presence bitmap for this vendor namespace
+ *	(this could be extended in the future if any vendor needs more
+ *	 bits, the radiotap spec does allow for that)
+ * @align: radiotap vendor namespace alignment. This defines the needed
+ *	alignment for the @data field below, not for the vendor namespace
+ *	description itself (which has a fixed 2-byte alignment)
+ *	Must be a power of two, and be set to at least 1!
+ * @oui: radiotap vendor namespace OUI
+ * @subns: radiotap vendor sub namespace
+ * @len: radiotap vendor sub namespace skip length, if alignment is done
+ *	then that's added to this, i.e. this is only the length of the
+ *	@data field.
+ * @pad: number of bytes of padding after the @data, this exists so that
+ *	the skb data alignment can be preserved even if the data has odd
+ *	length
+ * @data: the actual vendor namespace data
+ *
+ * This struct, including the vendor data, goes into the skb->data before
+ * the 802.11 header. It's split up in mac80211 using the align/oui/subns
+ * data.
+ */
+struct ieee80211_vendor_radiotap {
+	u32 present;
+	u8 align;
+	u8 oui[3];
+	u8 subns;
+	u8 pad;
+	u16 len;
+	u8 data[];
+} __packed;
+
+/**
  * enum ieee80211_conf_flags - configuration flags
  *
  * Flags to define PHY configuration options