nl80211: Implement shared_freq

This patch implements shared_freq handler for driver_nl80211.c. If a
"p2p_group_add" happens after legacy STA association, then this patch
will help to start the GO on the same frequency. This is useful when
supplicant is started on multiple interface running over a singly "PHY"
and the station interface is not used for the P2P device operations.

For example, wpa_supplicant -iwlan0 ..  -N -iwlan1 ... and wlan0 is used
for station connection and wlan1 as the P2P device interface.

Signed-hostap: Jithu Jance <jithu@broadcom.com>

src/drivers/driver_nl80211.c

@@ -7216,6 +7216,44 @@ static int nl80211_signal_poll(void *priv, struct wpa_signal_info *si)
 }
 
 
+static int wpa_driver_nl80211_shared_freq(void *priv)
+{
+	struct i802_bss *bss = priv;
+	struct wpa_driver_nl80211_data *drv = bss->drv;
+	struct wpa_driver_nl80211_data *driver;
+	int freq = 0;
+
+	/*
+	 * If the same PHY is in connected state with some other interface,
+	 * then retrieve the assoc freq.
+	 */
+	wpa_printf(MSG_DEBUG, "nl80211: Get shared freq for PHY %s",
+		   drv->phyname);
+
+	dl_list_for_each(driver, &drv->global->interfaces,
+			 struct wpa_driver_nl80211_data, list) {
+		if (drv == driver ||
+		    os_strcmp(drv->phyname, driver->phyname) != 0 ||
+		    !driver->associated)
+			continue;
+
+		wpa_printf(MSG_DEBUG, "nl80211: Found a match for PHY %s - %s "
+			   MACSTR,
+			   driver->phyname, driver->first_bss.ifname,
+			   MAC2STR(driver->addr));
+		freq = nl80211_get_assoc_freq(driver);
+		wpa_printf(MSG_DEBUG, "nl80211: Shared freq for PHY %s: %d",
+			   drv->phyname, freq);
+	}
+
+	if (!freq)
+		wpa_printf(MSG_DEBUG, "nl80211: No shared interface for "
+			   "PHY (%s) in associated state", drv->phyname);
+
+	return freq;
+}
+
+
 static int nl80211_send_frame(void *priv, const u8 *data, size_t data_len,
 			      int encrypt)
 {
@@ -7594,6 +7632,7 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.signal_monitor = nl80211_signal_monitor,
 	.signal_poll = nl80211_signal_poll,
 	.send_frame = nl80211_send_frame,
+	.shared_freq = wpa_driver_nl80211_shared_freq,
 	.set_param = nl80211_set_param,
 	.get_radio_name = nl80211_get_radio_name,
 	.add_pmkid = nl80211_add_pmkid,