nl80211: Export available antennas

Export the information which antennas are available for configuration as TX or
RX antennas via nl80211.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/nl80211.h

@@ -858,6 +858,12 @@ enum nl80211_commands {
  *	the hardware should not be configured to receive on this antenna.
  *	For a more detailed descripton see @NL80211_ATTR_WIPHY_ANTENNA_TX.
  *
+ * @NL80211_ATTR_WIPHY_ANTENNA_AVAIL_TX: Bitmap of antennas which are available
+ *	for configuration as TX antennas via the above parameters.
+ *
+ * @NL80211_ATTR_WIPHY_ANTENNA_AVAIL_RX: Bitmap of antennas which are available
+ *	for configuration as RX antennas via the above parameters.
+ *
  * @NL80211_ATTR_MCAST_RATE: Multicast tx rate (in 100 kbps) for IBSS
  *
  * @NL80211_ATTR_OFFCHANNEL_TX_OK: For management frame TX, the frame may be
@@ -1059,6 +1065,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_MESH_SETUP,
 
+	NL80211_ATTR_WIPHY_ANTENNA_AVAIL_TX,
+	NL80211_ATTR_WIPHY_ANTENNA_AVAIL_RX,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

net/wireless/nl80211.c

@@ -605,6 +605,11 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	if (dev->wiphy.flags & WIPHY_FLAG_CONTROL_PORT_PROTOCOL)
 		NLA_PUT_FLAG(msg, NL80211_ATTR_CONTROL_PORT_ETHERTYPE);
 
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_ANTENNA_AVAIL_TX,
+		    dev->wiphy.available_antennas_tx);
+	NLA_PUT_U32(msg, NL80211_ATTR_WIPHY_ANTENNA_AVAIL_RX,
+		    dev->wiphy.available_antennas_rx);
+
 	if ((dev->wiphy.available_antennas_tx ||
 	     dev->wiphy.available_antennas_rx) && dev->ops->get_antenna) {
 		u32 tx_ant = 0, rx_ant = 0;