cfg80211: clarify BSS probe response vs. beacon data

There are a few possible cases of where BSS data came from:
 1) only a beacon has been received
 2) only a probe response has been received
 3) the driver didn't report what it received (this happens when
    using cfg80211_inform_bss[_width]())
 4) both probe response and beacon data has been received

Unfortunately, in the userspace API, a few things weren't there:
 a) there was no way to differentiate cases 1) and 4) above
    without comparing the data of the IEs
 b) the TSF was always from the last frame, instead of being
    exposed for beacon/probe response separately like IEs

Fix this by
   i) exporting a new flag attribute that indicates whether or
      not probe response data has been received - this addresses (a)
  ii) exporting a BEACON_TSF attribute that holds the beacon's TSF
      if a beacon has been received
 iii) not exporting the beacon attributes in case (3) above as that
      would just lead userspace into thinking the data actually came
      from a beacon when that isn't clear

To implement this, track inside the IEs struct whether or not it
(definitely) came from a beacon.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7b8dac3efe8..77b85a89abc 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1503,12 +1503,14 @@ enum cfg80211_signal_type {
  * @tsf: TSF contained in the frame that carried these IEs
  * @rcu_head: internal use, for freeing
  * @len: length of the IEs
+ * @from_beacon: these IEs are known to come from a beacon
  * @data: IE data
  */
 struct cfg80211_bss_ies {
 	u64 tsf;
 	struct rcu_head rcu_head;
 	int len;
+	bool from_beacon;
 	u8 data[];
 };