mac80211: support RX_FLAG_MACTIME_END
Allow drivers to indicate their mactime is at RX completion and adjust
for this in mac80211. Also rename the existing RX_FLAG_MACTIME_MPDU to
RX_FLAG_MACTIME_START to clarify its intent. Based on similar code by
Johannes Berg.
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
[fix docs, atheros drivers]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index c7386b2..cc11558 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -543,30 +543,11 @@
if (ether_addr_equal(cbss->bssid, sdata->u.ibss.bssid))
goto put_bss;
- if (rx_status->flag & RX_FLAG_MACTIME_MPDU) {
- /*
- * For correct IBSS merging we need mactime; since mactime is
- * defined as the time the first data symbol of the frame hits
- * the PHY, and the timestamp of the beacon is defined as "the
- * time that the data symbol containing the first bit of the
- * timestamp is transmitted to the PHY plus the transmitting
- * STA's delays through its local PHY from the MAC-PHY
- * interface to its interface with the WM" (802.11 11.1.2)
- * - equals the time this bit arrives at the receiver - we have
- * to take into account the offset between the two.
- *
- * E.g. at 1 MBit that means mactime is 192 usec earlier
- * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
- */
- int rate;
-
- if (rx_status->flag & RX_FLAG_HT)
- rate = 65; /* TODO: HT rates */
- else
- rate = local->hw.wiphy->bands[band]->
- bitrates[rx_status->rate_idx].bitrate;
-
- rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
+ if (ieee80211_have_rx_timestamp(rx_status)) {
+ /* time when timestamp field was received */
+ rx_timestamp =
+ ieee80211_calculate_rx_timestamp(local, rx_status,
+ len + FCS_LEN, 24);
} else {
/*
* second best option: get current TSF
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e1fb97c..bff82a8 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1259,7 +1259,18 @@
is_broadcast_ether_addr(raddr);
}
+static inline bool
+ieee80211_have_rx_timestamp(struct ieee80211_rx_status *status)
+{
+ WARN_ON_ONCE(status->flag & RX_FLAG_MACTIME_START &&
+ status->flag & RX_FLAG_MACTIME_END);
+ return status->flag & (RX_FLAG_MACTIME_START | RX_FLAG_MACTIME_END);
+}
+u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
+ struct ieee80211_rx_status *status,
+ unsigned int mpdu_len,
+ unsigned int mpdu_offset);
int ieee80211_hw_config(struct ieee80211_local *local, u32 changed);
void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx);
void ieee80211_bss_info_change_notify(struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c
index 407c870..9c6ea9c 100644
--- a/net/mac80211/mesh_sync.c
+++ b/net/mac80211/mesh_sync.c
@@ -116,43 +116,13 @@
goto no_sync;
}
- if (rx_status->flag & RX_FLAG_MACTIME_MPDU && rx_status->mactime) {
- /*
- * The mactime is defined as the time the first data symbol
- * of the frame hits the PHY, and the timestamp of the beacon
- * is defined as "the time that the data symbol containing the
- * first bit of the timestamp is transmitted to the PHY plus
- * the transmitting STA's delays through its local PHY from the
- * MAC-PHY interface to its interface with the WM" (802.11
- * 11.1.2)
- *
- * T_r, in 13.13.2.2.2, is just defined as "the frame reception
- * time" but we unless we interpret that time to be the same
- * time of the beacon timestamp, the offset calculation will be
- * off. Below we adjust t_r to be "the time at which the first
- * symbol of the timestamp element in the beacon is received".
- * This correction depends on the rate.
- *
- * Based on similar code in ibss.c
- */
- int rate;
-
- if (rx_status->flag & RX_FLAG_HT) {
- /* TODO:
- * In principle there could be HT-beacons (Dual Beacon
- * HT Operation options), but for now ignore them and
- * just use the primary (i.e. non-HT) beacons for
- * synchronization.
- * */
- goto no_sync;
- } else
- rate = local->hw.wiphy->bands[rx_status->band]->
- bitrates[rx_status->rate_idx].bitrate;
-
- /* 24 bytes of header * 8 bits/byte *
- * 10*(100 Kbps)/Mbps / rate (100 Kbps)*/
- t_r = rx_status->mactime + (24 * 8 * 10 / rate);
- }
+ if (ieee80211_have_rx_timestamp(rx_status))
+ /* time when timestamp field was received */
+ t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
+ 24 + 12 +
+ elems->total_len +
+ FCS_LEN,
+ 24);
/* Timing offset calculation (see 13.13.2.2.2) */
t_t = le64_to_cpu(mgmt->u.beacon.timestamp);
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 6ad3303..e3daee8 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -81,7 +81,7 @@
/* always present fields */
len = sizeof(struct ieee80211_radiotap_header) + 9;
- if (status->flag & RX_FLAG_MACTIME_MPDU)
+ if (ieee80211_have_rx_timestamp(status))
len += 8;
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
len += 1;
@@ -117,6 +117,11 @@
struct ieee80211_radiotap_header *rthdr;
unsigned char *pos;
u16 rx_flags = 0;
+ int mpdulen;
+
+ mpdulen = skb->len;
+ if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
+ mpdulen += FCS_LEN;
rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
memset(rthdr, 0, rtap_len);
@@ -134,8 +139,11 @@
/* the order of the following fields is important */
/* IEEE80211_RADIOTAP_TSFT */
- if (status->flag & RX_FLAG_MACTIME_MPDU) {
- put_unaligned_le64(status->mactime, pos);
+ if (ieee80211_have_rx_timestamp(status)) {
+ put_unaligned_le64(
+ ieee80211_calculate_rx_timestamp(local, status,
+ mpdulen, 0),
+ pos);
rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
pos += 8;
}
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 4e4f585..5bad758 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2013,3 +2013,54 @@
return 2;
return 1;
}
+
+/**
+ * ieee80211_calculate_rx_timestamp - calculate timestamp in frame
+ * @local: mac80211 hw info struct
+ * @status: RX status
+ * @mpdu_len: total MPDU length (including FCS)
+ * @mpdu_offset: offset into MPDU to calculate timestamp at
+ *
+ * This function calculates the RX timestamp at the given MPDU offset, taking
+ * into account what the RX timestamp was. An offset of 0 will just normalize
+ * the timestamp to TSF at beginning of MPDU reception.
+ */
+u64 ieee80211_calculate_rx_timestamp(struct ieee80211_local *local,
+ struct ieee80211_rx_status *status,
+ unsigned int mpdu_len,
+ unsigned int mpdu_offset)
+{
+ u64 ts = status->mactime;
+ struct rate_info ri;
+ u16 rate;
+
+ if (WARN_ON(!ieee80211_have_rx_timestamp(status)))
+ return 0;
+
+ memset(&ri, 0, sizeof(ri));
+
+ /* Fill cfg80211 rate info */
+ if (status->flag & RX_FLAG_HT) {
+ ri.mcs = status->rate_idx;
+ ri.flags |= RATE_INFO_FLAGS_MCS;
+ if (status->flag & RX_FLAG_40MHZ)
+ ri.flags |= RATE_INFO_FLAGS_40_MHZ_WIDTH;
+ if (status->flag & RX_FLAG_SHORT_GI)
+ ri.flags |= RATE_INFO_FLAGS_SHORT_GI;
+ } else {
+ struct ieee80211_supported_band *sband;
+
+ sband = local->hw.wiphy->bands[status->band];
+ ri.legacy = sband->bitrates[status->rate_idx].bitrate;
+ }
+
+ rate = cfg80211_calculate_bitrate(&ri);
+
+ /* rewind from end of MPDU */
+ if (status->flag & RX_FLAG_MACTIME_END)
+ ts -= mpdu_len * 8 * 10 / rate;
+
+ ts += mpdu_offset * 8 * 10 / rate;
+
+ return ts;
+}