mac80211: add freq_offset to RX status

RX status needs a KHz component, so add freq_offset. We
can reduce the bits for the frequency since 60 GHz isn't
supported.
Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200402011810.22947-5-thomas@adapt-ip.com
[fix commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1335,6 +1335,7 @@ enum mac80211_rx_encoding {
  * @freq: frequency the radio was tuned to when receiving this frame, in MHz
  *	This field must be set for management frames, but isn't strictly needed
  *	for data (other) frames - for those it only affects radiotap reporting.
+ * @freq_offset: @freq has a positive offset of 500Khz.
  * @signal: signal strength when receiving this frame, either in dBm, in dB or
  *	unspecified depending on the hardware capabilities flags
  *	@IEEE80211_HW_SIGNAL_*
@@ -1365,7 +1366,7 @@ struct ieee80211_rx_status {
 	u32 device_timestamp;
 	u32 ampdu_reference;
 	u32 flag;
-	u16 freq;
+	u16 freq: 13, freq_offset: 1;
 	u8 enc_flags;
 	u8 encoding:2, bw:3, he_ru:3;
 	u8 he_gi:2, he_dcm:1;
@@ -1381,6 +1382,13 @@ struct ieee80211_rx_status {
 	u8 zero_length_psdu_type;
 };
 
+static inline u32
+ieee80211_rx_status_to_khz(struct ieee80211_rx_status *rx_status)
+{
+	return MHZ_TO_KHZ(rx_status->freq) +
+	       (rx_status->freq_offset ? 500 : 0);
+}
+
 /**
  * struct ieee80211_vendor_radiotap - vendor radiotap data information
  * @present: presence bitmap for this vendor namespace

net/mac80211/mlme.c

@@ -3683,7 +3683,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 
 	sdata_assert_lock(sdata);
 
-	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
+	channel = ieee80211_get_channel_khz(local->hw.wiphy,
+					ieee80211_rx_status_to_khz(rx_status));
 	if (!channel)
 		return;
 
@@ -3899,7 +3900,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 		return;
 	}
 
-	if (rx_status->freq != chanctx_conf->def.chan->center_freq) {
+	if (ieee80211_rx_status_to_khz(rx_status) !=
+	    ieee80211_channel_to_khz(chanctx_conf->def.chan)) {
 		rcu_read_unlock();
 		return;
 	}

net/mac80211/rx.c

@@ -412,6 +412,7 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 	pos++;
 
 	/* IEEE80211_RADIOTAP_CHANNEL */
+	/* TODO: frequency offset in KHz */
 	put_unaligned_le16(status->freq, pos);
 	pos += 2;
 	if (status->bw == RATE_INFO_BW_10)

net/mac80211/scan.c

@@ -275,7 +275,8 @@ void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb)
 			return;
 	}
 
-	channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq);
+	channel = ieee80211_get_channel_khz(local->hw.wiphy,
+					ieee80211_rx_status_to_khz(rx_status));
 
 	if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 		return;