mac80211: add support for radiotap timestamp field

Use the existing device timestamp from the RX status information
to add support for the new radiotap timestamp field. Currently
only 32-bit counters are supported, but we also add the radiotap
mactime where applicable. This new field allows more flexibility
in where the timestamp is taken etc. The non-timestamp data in
the field is taken from a new field in the hw struct.

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

diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index b0fd947..ba07b9d 100644 (file)
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -190,6 +190,10 @@ struct ieee80211_radiotap_header {
  * IEEE80211_RADIOTAP_VHT      u16, u8, u8, u8[4], u8, u8, u16
  *
  *     Contains VHT information about this frame.
+ *
+ * IEEE80211_RADIOTAP_TIMESTAMP                u64, u16, u8, u8        variable
+ *
+ *     Contains timestamp information for this frame.
  */
 enum ieee80211_radiotap_type {
        IEEE80211_RADIOTAP_TSFT = 0,
@@ -214,6 +218,7 @@ enum ieee80211_radiotap_type {
        IEEE80211_RADIOTAP_MCS = 19,
        IEEE80211_RADIOTAP_AMPDU_STATUS = 20,
        IEEE80211_RADIOTAP_VHT = 21,
+       IEEE80211_RADIOTAP_TIMESTAMP = 22,
 
        /* valid in every it_present bitmap, even vendor namespaces */
        IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
@@ -321,6 +326,22 @@ enum ieee80211_radiotap_type {
 #define IEEE80211_RADIOTAP_CODING_LDPC_USER2                   0x04
 #define IEEE80211_RADIOTAP_CODING_LDPC_USER3                   0x08
 
+/* For IEEE80211_RADIOTAP_TIMESTAMP */
+#define IEEE80211_RADIOTAP_TIMESTAMP_UNIT_MASK                 0x000F
+#define IEEE80211_RADIOTAP_TIMESTAMP_UNIT_MS                   0x0000
+#define IEEE80211_RADIOTAP_TIMESTAMP_UNIT_US                   0x0001
+#define IEEE80211_RADIOTAP_TIMESTAMP_UNIT_NS                   0x0003
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_MASK                 0x00F0
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_BEGIN_MDPU           0x0000
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_EO_MPDU              0x0010
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_EO_PPDU              0x0020
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_PLCP_SIG_ACQ         0x0030
+#define IEEE80211_RADIOTAP_TIMESTAMP_SPOS_UNKNOWN              0x00F0
+
+#define IEEE80211_RADIOTAP_TIMESTAMP_FLAG_64BIT                        0x00
+#define IEEE80211_RADIOTAP_TIMESTAMP_FLAG_32BIT                        0x01
+#define IEEE80211_RADIOTAP_TIMESTAMP_FLAG_ACCURACY             0x02
+
 /* helpers */
 static inline int ieee80211_get_radiotap_len(unsigned char *data)
 {

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index a1457ca..08bac23 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2145,6 +2145,14 @@ enum ieee80211_hw_flags {
  *     the default is _GI | _BANDWIDTH.
  *     Use the %IEEE80211_RADIOTAP_VHT_KNOWN_* values.
  *
+ * @radiotap_timestamp: Information for the radiotap timestamp field; if the
+ *     'units_pos' member is set to a non-negative value it must be set to
+ *     a combination of a IEEE80211_RADIOTAP_TIMESTAMP_UNIT_* and a
+ *     IEEE80211_RADIOTAP_TIMESTAMP_SPOS_* value, and then the timestamp
+ *     field will be added and populated from the &struct ieee80211_rx_status
+ *     device_timestamp. If the 'accuracy' member is non-negative, it's put
+ *     into the accuracy radiotap field and the accuracy known flag is set.
+ *
  * @netdev_features: netdev features to be set in each netdev created
  *     from this HW. Note that not all features are usable with mac80211,
  *     other features will be rejected during HW registration.
@@ -2188,6 +2196,10 @@ struct ieee80211_hw {
        u8 offchannel_tx_hw_queue;
        u8 radiotap_mcs_details;
        u16 radiotap_vht_details;
+       struct {
+               int units_pos;
+               s16 accuracy;
+       } radiotap_timestamp;
        netdev_features_t netdev_features;
        u8 uapsd_queues;
        u8 uapsd_max_sp_len;

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index d00ea9b..ac053a9 100644 (file)
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -660,6 +660,9 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
 
        ieee80211_roc_setup(local);
 
+       local->hw.radiotap_timestamp.units_pos = -1;
+       local->hw.radiotap_timestamp.accuracy = -1;
+
        return &local->hw;
  err_free:
        wiphy_free(wiphy);

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 6a265aa..284f0f2 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -180,6 +180,11 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
                len += 12;
        }
 
+       if (local->hw.radiotap_timestamp.units_pos >= 0) {
+               len = ALIGN(len, 8);
+               len += 12;
+       }
+
        if (status->chains) {
                /* antenna and antenna signal fields */
                len += 2 * hweight8(status->chains);
@@ -447,6 +452,31 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
                pos += 2;
        }
 
+       if (local->hw.radiotap_timestamp.units_pos >= 0) {
+               u16 accuracy = 0;
+               u8 flags = IEEE80211_RADIOTAP_TIMESTAMP_FLAG_32BIT;
+
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_TIMESTAMP);
+
+               /* ensure 8 byte alignment */
+               while ((pos - (u8 *)rthdr) & 7)
+                       pos++;
+
+               put_unaligned_le64(status->device_timestamp, pos);
+               pos += sizeof(u64);
+
+               if (local->hw.radiotap_timestamp.accuracy >= 0) {
+                       accuracy = local->hw.radiotap_timestamp.accuracy;
+                       flags |= IEEE80211_RADIOTAP_TIMESTAMP_FLAG_ACCURACY;
+               }
+               put_unaligned_le16(accuracy, pos);
+               pos += sizeof(u16);
+
+               *pos++ = local->hw.radiotap_timestamp.units_pos;
+               *pos++ = flags;
+       }
+
        for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
                *pos++ = status->chain_signal[chain];
                *pos++ = chain;