nl80211: allow BSS data to include CLOCK_BOOTTIME timestamp

For location and connectivity services, userspace would often like
to know the time when the BSS was last seen. The current "last seen"
value is calculated in a way that makes it less useful, especially
if the system suspended in the meantime.

Add the ability for the driver to report a real CLOCK_BOOTTIME stamp
that can then be reported to userspace (if present).

Drivers wishing to use this must be converted to the new API to call
cfg80211_inform_bss_data() or cfg80211_inform_bss_frame_data(). They
need to ensure the reported value is accurate enough even when the
frame might have been buffered in the device (e.g. firmware.)

Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
[modified to use struct, inlines]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

2 files changed, 80 insertions, 19 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 90332a1838cc..7f1e9ee844e2 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1576,6 +1576,26 @@ enum cfg80211_signal_type {
 };
 
 /**
+ * struct cfg80211_inform_bss - BSS inform data
+ * @chan: channel the frame was received on
+ * @scan_width: scan width that was used
+ * @signal: signal strength value, according to the wiphy's
+ *	signal type
+ * @boottime_ns: timestamp (CLOCK_BOOTTIME) when the information was
+ *	received; should match the time when the frame was actually
+ *	received by the device (not just by the host, in case it was
+ *	buffered on the device) and be accurate to about 10ms.
+ *	If the frame isn't buffered, just passing the return value of
+ *	ktime_get_boot_ns() is likely appropriate.
+ */
+struct cfg80211_inform_bss {
+	struct ieee80211_channel *chan;
+	enum nl80211_bss_scan_width scan_width;
+	s32 signal;
+	u64 boottime_ns;
+};
+
+/**
  * struct cfg80211_bss_ie_data - BSS entry IE data
  * @tsf: TSF contained in the frame that carried these IEs
  * @rcu_head: internal use, for freeing
@@ -3958,14 +3978,11 @@ void cfg80211_sched_scan_stopped(struct wiphy *wiphy);
 void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy);
 
 /**
- * cfg80211_inform_bss_width_frame - inform cfg80211 of a received BSS frame
- *
+ * cfg80211_inform_bss_frame_data - inform cfg80211 of a received BSS frame
  * @wiphy: the wiphy reporting the BSS
- * @rx_channel: The channel the frame was received on
- * @scan_width: width of the control channel
+ * @data: the BSS metadata
  * @mgmt: the management frame (probe response or beacon)
  * @len: length of the management frame
- * @signal: the signal strength, type depends on the wiphy's signal_type
  * @gfp: context flags
  *
  * This informs cfg80211 that BSS information was found and
@@ -3975,11 +3992,26 @@ void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy);
  * Or %NULL on error.
  */
 struct cfg80211_bss * __must_check
+cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
+			       struct cfg80211_inform_bss *data,
+			       struct ieee80211_mgmt *mgmt, size_t len,
+			       gfp_t gfp);
+
+static inline struct cfg80211_bss * __must_check
 cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 				struct ieee80211_channel *rx_channel,
 				enum nl80211_bss_scan_width scan_width,
 				struct ieee80211_mgmt *mgmt, size_t len,
-				s32 signal, gfp_t gfp);
+				s32 signal, gfp_t gfp)
+{
+	struct cfg80211_inform_bss data = {
+		.chan = rx_channel,
+		.scan_width = scan_width,
+		.signal = signal,
+	};
+
+	return cfg80211_inform_bss_frame_data(wiphy, &data, mgmt, len, gfp);
+}
 
 static inline struct cfg80211_bss * __must_check
 cfg80211_inform_bss_frame(struct wiphy *wiphy,
@@ -3987,9 +4019,13 @@ cfg80211_inform_bss_frame(struct wiphy *wiphy,
 			  struct ieee80211_mgmt *mgmt, size_t len,
 			  s32 signal, gfp_t gfp)
 {
-	return cfg80211_inform_bss_width_frame(wiphy, rx_channel,
-					       NL80211_BSS_CHAN_WIDTH_20,
-					       mgmt, len, signal, gfp);
+	struct cfg80211_inform_bss data = {
+		.chan = rx_channel,
+		.scan_width = NL80211_BSS_CHAN_WIDTH_20,
+		.signal = signal,
+	};
+
+	return cfg80211_inform_bss_frame_data(wiphy, &data, mgmt, len, gfp);
 }
 
 /**
@@ -4006,11 +4042,10 @@ enum cfg80211_bss_frame_type {
 };
 
 /**
- * cfg80211_inform_bss_width - inform cfg80211 of a new BSS
+ * cfg80211_inform_bss_data - inform cfg80211 of a new BSS
  *
  * @wiphy: the wiphy reporting the BSS
- * @rx_channel: The channel the frame was received on
- * @scan_width: width of the control channel
+ * @data: the BSS metadata
  * @ftype: frame type (if known)
  * @bssid: the BSSID of the BSS
  * @tsf: the TSF sent by the peer in the beacon/probe response (or 0)
@@ -4018,7 +4053,6 @@ enum cfg80211_bss_frame_type {
  * @beacon_interval: the beacon interval announced by the peer
  * @ie: additional IEs sent by the peer
  * @ielen: length of the additional IEs
- * @signal: the signal strength, type depends on the wiphy's signal_type
  * @gfp: context flags
  *
  * This informs cfg80211 that BSS information was found and
@@ -4028,13 +4062,32 @@ enum cfg80211_bss_frame_type {
  * Or %NULL on error.
  */
 struct cfg80211_bss * __must_check
+cfg80211_inform_bss_data(struct wiphy *wiphy,
+			 struct cfg80211_inform_bss *data,
+			 enum cfg80211_bss_frame_type ftype,
+			 const u8 *bssid, u64 tsf, u16 capability,
+			 u16 beacon_interval, const u8 *ie, size_t ielen,
+			 gfp_t gfp);
+
+static inline struct cfg80211_bss * __must_check
 cfg80211_inform_bss_width(struct wiphy *wiphy,
 			  struct ieee80211_channel *rx_channel,
 			  enum nl80211_bss_scan_width scan_width,
 			  enum cfg80211_bss_frame_type ftype,
 			  const u8 *bssid, u64 tsf, u16 capability,
 			  u16 beacon_interval, const u8 *ie, size_t ielen,
-			  s32 signal, gfp_t gfp);
+			  s32 signal, gfp_t gfp)
+{
+	struct cfg80211_inform_bss data = {
+		.chan = rx_channel,
+		.scan_width = scan_width,
+		.signal = signal,
+	};
+
+	return cfg80211_inform_bss_data(wiphy, &data, ftype, bssid, tsf,
+					capability, beacon_interval, ie, ielen,
+					gfp);
+}
 
 static inline struct cfg80211_bss * __must_check
 cfg80211_inform_bss(struct wiphy *wiphy,
@@ -4044,11 +4097,15 @@ cfg80211_inform_bss(struct wiphy *wiphy,
 		    u16 beacon_interval, const u8 *ie, size_t ielen,
 		    s32 signal, gfp_t gfp)
 {
-	return cfg80211_inform_bss_width(wiphy, rx_channel,
-					 NL80211_BSS_CHAN_WIDTH_20, ftype,
-					 bssid, tsf, capability,
-					 beacon_interval, ie, ielen, signal,
-					 gfp);
+	struct cfg80211_inform_bss data = {
+		.chan = rx_channel,
+		.scan_width = NL80211_BSS_CHAN_WIDTH_20,
+		.signal = signal,
+	};
+
+	return cfg80211_inform_bss_data(wiphy, &data, ftype, bssid, tsf,
+					capability, beacon_interval, ie, ielen,
+					gfp);
 }
 
 struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index c0ab6b0a3919..5dadb844fe18 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3364,6 +3364,9 @@ enum nl80211_bss_scan_width {
  *	(not present if no beacon frame has been received yet)
  * @NL80211_BSS_PRESP_DATA: the data in @NL80211_BSS_INFORMATION_ELEMENTS and
  *	@NL80211_BSS_TSF is known to be from a probe response (flag attribute)
+ * @NL80211_BSS_LAST_SEEN_BOOTTIME: CLOCK_BOOTTIME timestamp when this entry
+ *	was last updated by a received frame. The value is expected to be
+ *	accurate to about 10ms. (u64, nanoseconds)
  * @__NL80211_BSS_AFTER_LAST: internal
  * @NL80211_BSS_MAX: highest BSS attribute
  */
@@ -3383,6 +3386,7 @@ enum nl80211_bss {
 	NL80211_BSS_CHAN_WIDTH,
 	NL80211_BSS_BEACON_TSF,
 	NL80211_BSS_PRESP_DATA,
+	NL80211_BSS_LAST_SEEN_BOOTTIME,
 
 	/* keep last */
 	__NL80211_BSS_AFTER_LAST,