cfg80211: Add AP beacon regulatory hints

When devices are world roaming they cannot beacon or do active scan
on 5 GHz or on channels 12, 13 and 14 on the 2 GHz band. Although
we have a good regulatory API some cards may _always_ world roam, this
is also true when a system does not have CRDA present. Devices doing world
roaming can still passive scan, if they find a beacon from an AP on
one of the world roaming frequencies we make the assumption we can do
the same and we also remove the passive scan requirement.

This adds support for providing beacon regulatory hints based on scans.
This works for devices that do either hardware or software scanning.
If a channel has not yet been marked as having had a beacon present
on it we queue the beacon hint processing into the workqueue.

All wireless devices will benefit from beacon regulatory hints from
any wireless device on a system including new devices connected to
the system at a later time.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/net/wireless/reg.h b/net/wireless/reg.h
index 4730def5a69d..65bfd0558ce1 100644
--- a/net/wireless/reg.h
+++ b/net/wireless/reg.h
@@ -38,4 +38,25 @@ extern int __regulatory_hint(struct wiphy *wiphy, enum reg_set_by set_by,
                              const char *alpha2, u32 country_ie_checksum,
                              enum environment_cap country_ie_env);
 
+/**
+ * regulatory_hint_found_beacon - hints a beacon was found on a channel
+ * @wiphy: the wireless device where the beacon was found on
+ * @beacon_chan: the channel on which the beacon was found on
+ * @gfp: context flags
+ *
+ * This informs the wireless core that a beacon from an AP was found on
+ * the channel provided. This allows the wireless core to make educated
+ * guesses on regulatory to help with world roaming. This is only used for
+ * world roaming -- when we do not know our current location. This is
+ * only useful on channels 12, 13 and 14 on the 2 GHz band as channels
+ * 1-11 are already enabled by the world regulatory domain; and on
+ * non-radar 5 GHz channels.
+ *
+ * Drivers do not need to call this, cfg80211 will do it for after a scan
+ * on a newly found BSS.
+ */
+int regulatory_hint_found_beacon(struct wiphy *wiphy,
+                                        struct ieee80211_channel *beacon_chan,
+                                        gfp_t gfp);
+
 #endif  /* __NET_WIRELESS_REG_H */