cfg80211: export expected throughput through get_station()

Users may need information about the expected throughput
towards a given peer.
This value is supposed to consider the size overhead
generated by the 802.11 header.

This value is exported in kbps through the get_station() API
by including it into the station_info object.
Moreover, it is sent to user space when replying to the
nl80211 GET_STATION command.

This information will be useful to the batman-adv module
which will use it for its new metric computation.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 49adf58..62bdb1a 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3650,6 +3650,10 @@
 	    nla_put_u32(msg, NL80211_STA_INFO_TX_FAILED,
 			sinfo->tx_failed))
 		goto nla_put_failure;
+	if ((sinfo->filled & STATION_INFO_EXPECTED_THROUGHPUT) &&
+	    nla_put_u32(msg, NL80211_STA_INFO_EXPECTED_THROUGHPUT,
+			sinfo->expected_throughput))
+		goto nla_put_failure;
 	if ((sinfo->filled & STATION_INFO_BEACON_LOSS_COUNT) &&
 	    nla_put_u32(msg, NL80211_STA_INFO_BEACON_LOSS,
 			sinfo->beacon_loss_count))