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>

4 files changed, 47 insertions, 39 deletions

diff --git a/net/wireless/core.h b/net/wireless/core.h
index b9d5bc8c148d..a618b4b86fa4 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -137,6 +137,7 @@ struct cfg80211_internal_bss {
 	struct list_head list;
 	struct list_head hidden_list;
 	struct rb_node rbn;
+	u64 ts_boottime;
 	unsigned long ts;
 	unsigned long refcount;
 	atomic_t hold;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index f05ba8b7af61..fb0712b3d9cb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6605,6 +6605,11 @@ static int nl80211_send_bss(struct sk_buff *msg, struct netlink_callback *cb,
 			jiffies_to_msecs(jiffies - intbss->ts)))
 		goto nla_put_failure;
 
+	if (intbss->ts_boottime &&
+	    nla_put_u64(msg, NL80211_BSS_LAST_SEEN_BOOTTIME,
+			intbss->ts_boottime))
+		goto nla_put_failure;
+
 	switch (rdev->wiphy.signal_type) {
 	case CFG80211_SIGNAL_TYPE_MBM:
 		if (nla_put_u32(msg, NL80211_BSS_SIGNAL_MBM, res->signal))
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 3a50aa2553bf..3feaa03aa046 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -839,6 +839,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 			found->pub.signal = tmp->pub.signal;
 		found->pub.capability = tmp->pub.capability;
 		found->ts = tmp->ts;
+		found->ts_boottime = tmp->ts_boottime;
 	} else {
 		struct cfg80211_internal_bss *new;
 		struct cfg80211_internal_bss *hidden;
@@ -938,14 +939,13 @@ cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
 }
 
 /* Returned bss is reference counted and must be cleaned up appropriately. */
-struct cfg80211_bss*
-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)
+struct cfg80211_bss *
+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)
 {
 	struct cfg80211_bss_ies *ies;
 	struct ieee80211_channel *channel;
@@ -957,19 +957,21 @@ cfg80211_inform_bss_width(struct wiphy *wiphy,
 		return NULL;
 
 	if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
-			(signal < 0 || signal > 100)))
+		    (data->signal < 0 || data->signal > 100)))
 		return NULL;
 
-	channel = cfg80211_get_bss_channel(wiphy, ie, ielen, rx_channel);
+	channel = cfg80211_get_bss_channel(wiphy, ie, ielen, data->chan);
 	if (!channel)
 		return NULL;
 
 	memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
 	tmp.pub.channel = channel;
-	tmp.pub.scan_width = scan_width;
-	tmp.pub.signal = signal;
+	tmp.pub.scan_width = data->scan_width;
+	tmp.pub.signal = data->signal;
 	tmp.pub.beacon_interval = beacon_interval;
 	tmp.pub.capability = capability;
+	tmp.ts_boottime = data->boottime_ns;
+
 	/*
 	 * If we do not know here whether the IEs are from a Beacon or Probe
 	 * Response frame, we need to pick one of the options and only use it
@@ -999,7 +1001,7 @@ cfg80211_inform_bss_width(struct wiphy *wiphy,
 	}
 	rcu_assign_pointer(tmp.pub.ies, ies);
 
-	signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
+	signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
 		wiphy->max_adj_channel_rssi_comp;
 	res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
 	if (!res)
@@ -1019,15 +1021,15 @@ cfg80211_inform_bss_width(struct wiphy *wiphy,
 	/* cfg80211_bss_update gives us a referenced result */
 	return &res->pub;
 }
-EXPORT_SYMBOL(cfg80211_inform_bss_width);
+EXPORT_SYMBOL(cfg80211_inform_bss_data);
 
-/* Returned bss is reference counted and must be cleaned up appropriately. */
+/* cfg80211_inform_bss_width_frame helper */
 struct cfg80211_bss *
-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)
+cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
+			       struct cfg80211_inform_bss *data,
+			       struct ieee80211_mgmt *mgmt, size_t len,
+			       gfp_t gfp)
+
 {
 	struct cfg80211_internal_bss tmp = {}, *res;
 	struct cfg80211_bss_ies *ies;
@@ -1040,8 +1042,7 @@ cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 	BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
 			offsetof(struct ieee80211_mgmt, u.beacon.variable));
 
-	trace_cfg80211_inform_bss_width_frame(wiphy, rx_channel, scan_width, mgmt,
-					      len, signal);
+	trace_cfg80211_inform_bss_frame(wiphy, data, mgmt, len);
 
 	if (WARN_ON(!mgmt))
 		return NULL;
@@ -1050,14 +1051,14 @@ cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 		return NULL;
 
 	if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
-		    (signal < 0 || signal > 100)))
+		    (data->signal < 0 || data->signal > 100)))
 		return NULL;
 
 	if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
 		return NULL;
 
 	channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
-					   ielen, rx_channel);
+					   ielen, data->chan);
 	if (!channel)
 		return NULL;
 
@@ -1077,12 +1078,13 @@ cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 	
 	memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
 	tmp.pub.channel = channel;
-	tmp.pub.scan_width = scan_width;
-	tmp.pub.signal = signal;
+	tmp.pub.scan_width = data->scan_width;
+	tmp.pub.signal = data->signal;
 	tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
 	tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
+	tmp.ts_boottime = data->boottime_ns;
 
-	signal_valid = abs(rx_channel->center_freq - channel->center_freq) <=
+	signal_valid = abs(data->chan->center_freq - channel->center_freq) <=
 		wiphy->max_adj_channel_rssi_comp;
 	res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid);
 	if (!res)
@@ -1102,7 +1104,7 @@ cfg80211_inform_bss_width_frame(struct wiphy *wiphy,
 	/* cfg80211_bss_update gives us a referenced result */
 	return &res->pub;
 }
-EXPORT_SYMBOL(cfg80211_inform_bss_width_frame);
+EXPORT_SYMBOL(cfg80211_inform_bss_frame_data);
 
 void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
 {
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index a808279a432a..0c392d36781b 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -2670,30 +2670,30 @@ TRACE_EVENT(cfg80211_get_bss,
 		  __entry->privacy)
 );
 
-TRACE_EVENT(cfg80211_inform_bss_width_frame,
-	TP_PROTO(struct wiphy *wiphy, struct ieee80211_channel *channel,
-		 enum nl80211_bss_scan_width scan_width,
-		 struct ieee80211_mgmt *mgmt, size_t len,
-		 s32 signal),
-	TP_ARGS(wiphy, channel, scan_width, mgmt, len, signal),
+TRACE_EVENT(cfg80211_inform_bss_frame,
+	TP_PROTO(struct wiphy *wiphy, struct cfg80211_inform_bss *data,
+		 struct ieee80211_mgmt *mgmt, size_t len),
+	TP_ARGS(wiphy, data, mgmt, len),
 	TP_STRUCT__entry(
 		WIPHY_ENTRY
 		CHAN_ENTRY
 		__field(enum nl80211_bss_scan_width, scan_width)
 		__dynamic_array(u8, mgmt, len)
 		__field(s32, signal)
+		__field(u64, ts_boottime)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
-		CHAN_ASSIGN(channel);
-		__entry->scan_width = scan_width;
+		CHAN_ASSIGN(data->chan);
+		__entry->scan_width = data->scan_width;
 		if (mgmt)
 			memcpy(__get_dynamic_array(mgmt), mgmt, len);
-		__entry->signal = signal;
+		__entry->signal = data->signal;
+		__entry->ts_boottime = data->boottime_ns;
 	),
-	TP_printk(WIPHY_PR_FMT ", " CHAN_PR_FMT "(scan_width: %d) signal: %d",
+	TP_printk(WIPHY_PR_FMT ", " CHAN_PR_FMT "(scan_width: %d) signal: %d, tsb:%llu",
 		  WIPHY_PR_ARG, CHAN_PR_ARG, __entry->scan_width,
-		  __entry->signal)
+		  __entry->signal, (unsigned long long)__entry->ts_boottime)
 );
 
 DECLARE_EVENT_CLASS(cfg80211_bss_evt,