mac80211: accept public action frames with mismatched BSSID

Arik's patch "mac80211: allow action frames with unknown
BSSID in GO mode" allowed any action frames in P2P mode
to go through, but only to cooked monitor interfaces as
the IEEE80211_RX_RA_MATCH was still cleared. As a result
my no-monitor patches broke invitation responses.

Instead of allowing any action frames in P2P GO mode to
go through with a wrong BSSID like that patch did, allow
all public action frames. They will never be processed
by mac80211, but can be reported via nl80211 then.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 66cedf6..17f2a76 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -1695,6 +1695,23 @@
 }
 
 /**
+ * ieee80211_is_public_action - check if frame is a public action frame
+ * @hdr: the frame
+ * @len: length of the frame
+ */
+static inline bool ieee80211_is_public_action(struct ieee80211_hdr *hdr,
+					      size_t len)
+{
+	struct ieee80211_mgmt *mgmt = (void *)hdr;
+
+	if (len < IEEE80211_MIN_ACTION_SIZE)
+		return false;
+	if (!ieee80211_is_action(hdr->frame_control))
+		return false;
+	return mgmt->u.action.category == WLAN_CATEGORY_PUBLIC;
+}
+
+/**
  * ieee80211_fhss_chan_to_freq - get channel frequency
  * @channel: the FHSS channel
  *