mac80211: support reporting 0-length PSDU in radiotap

For certain sounding frames, it may be useful to report them
to userspace even though they don't have a PSDU in order to
determine the PHY parameters (e.g. VHT rate/stream config.)
Add support for this to mac80211.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index 80d543902b8b43eb90f52b29309cf3f9e5733ab2..8014153bdd4975a1e3440aea08d181856e561b27 100644 (file)
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -75,6 +75,7 @@ enum ieee80211_radiotap_presence {
        IEEE80211_RADIOTAP_TIMESTAMP = 22,
        IEEE80211_RADIOTAP_HE = 23,
        IEEE80211_RADIOTAP_HE_MU = 24,
+       IEEE80211_RADIOTAP_ZERO_LEN_PSDU = 26,
        IEEE80211_RADIOTAP_LSIG = 27,
 
        /* valid in every it_present bitmap, even vendor namespaces */
@@ -340,6 +341,11 @@ struct ieee80211_radiotap_lsig {
        __le16 data1, data2;
 };
 
+enum ieee80211_radiotap_zero_len_psdu_type {
+       IEEE80211_RADIOTAP_ZERO_LEN_PSDU_SOUNDING               = 0,
+       IEEE80211_RADIOTAP_ZERO_LEN_PSDU_VENDOR                 = 0xff,
+};
+
 /**
  * ieee80211_get_radiotap_len - get radiotap header length
  */

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 8c26d2d36cbec16fde3df1480a844b21f019307d..50bf598abdfd8670ec91dc8ff6527ceac31c5dab 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1142,6 +1142,10 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info)
  * @RX_FLAG_RADIOTAP_HE_MU: HE MU radiotap data is present
  *     (&struct ieee80211_radiotap_he_mu)
  * @RX_FLAG_RADIOTAP_LSIG: L-SIG radiotap data is present
+ * @RX_FLAG_NO_PSDU: use the frame only for radiotap reporting, with
+ *     the "0-length PSDU" field included there.  The value for it is
+ *     in &struct ieee80211_rx_status.  Note that if this value isn't
+ *     known the frame shouldn't be reported.
  */
 enum mac80211_rx_flags {
        RX_FLAG_MMIC_ERROR              = BIT(0),
@@ -1173,6 +1177,7 @@ enum mac80211_rx_flags {
        RX_FLAG_RADIOTAP_HE             = BIT(26),
        RX_FLAG_RADIOTAP_HE_MU          = BIT(27),
        RX_FLAG_RADIOTAP_LSIG           = BIT(28),
+       RX_FLAG_NO_PSDU                 = BIT(29),
 };
 
 /**
@@ -1245,6 +1250,7 @@ enum mac80211_rx_encoding {
  * @ampdu_reference: A-MPDU reference number, must be a different value for
  *     each A-MPDU but the same for each subframe within one A-MPDU
  * @ampdu_delimiter_crc: A-MPDU delimiter CRC
+ * @zero_length_psdu_type: radiotap type of the 0-length PSDU
  */
 struct ieee80211_rx_status {
        u64 mactime;
@@ -1265,6 +1271,7 @@ struct ieee80211_rx_status {
        u8 chains;
        s8 chain_signal[IEEE80211_MAX_CHAINS];
        u8 ampdu_delimiter_crc;
+       u8 zero_length_psdu_type;
 };
 
 /**

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 4376a4ce8c25df75b3d6f500a2b72ddfc1b69318..c6bfd4019d44dde2d5ea5d42266d501ae0e50f8a 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -115,7 +115,8 @@ static inline bool should_drop_frame(struct sk_buff *skb, int present_fcs_len,
 
        if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
                            RX_FLAG_FAILED_PLCP_CRC |
-                           RX_FLAG_ONLY_MONITOR))
+                           RX_FLAG_ONLY_MONITOR |
+                           RX_FLAG_NO_PSDU))
                return true;
 
        if (unlikely(skb->len < 16 + present_fcs_len + rtap_space))
@@ -189,6 +190,9 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
                BUILD_BUG_ON(sizeof(struct ieee80211_radiotap_he_mu) != 12);
        }
 
+       if (status->flag & RX_FLAG_NO_PSDU)
+               len += 1;
+
        if (status->flag & RX_FLAG_RADIOTAP_LSIG) {
                len = ALIGN(len, 2);
                len += 4;
@@ -642,6 +646,12 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
                pos += sizeof(he_mu);
        }
 
+       if (status->flag & RX_FLAG_NO_PSDU) {
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_ZERO_LEN_PSDU);
+               *pos++ = status->zero_length_psdu_type;
+       }
+
        if (status->flag & RX_FLAG_RADIOTAP_LSIG) {
                /* ensure 2 byte alignment */
                while ((pos - (u8 *)rthdr) & 1)