Add driver command and event for signal strength monitoring

src/drivers/driver.h

@@ -1758,6 +1758,22 @@ struct wpa_driver_ops {
 	 * @priv: Private driver interface data
 	 */
 	void (*resume)(void *priv);
+
+	/**
+	 * signal_monitor - Set signal monitoring parameters
+	 * @priv: Private driver interface data
+	 * @threshold: Threshold value for signal change events; 0 = disabled
+	 * @hysteresis: Minimum change in signal strength before indicating a
+	 *	new event
+	 * Returns: 0 on success, -1 on failure (or if not supported)
+	 *
+	 * This function can be used to configure monitoring of signal strength
+	 * with the current AP. Whenever signal strength drops below the
+	 * %threshold value or increases above it, EVENT_SIGNAL_CHANGE event
+	 * should be generated assuming the signal strength has changed at
+	 * least %hysteresis from the previously indicated signal change event.
+	 */
+	int (*signal_monitor)(void *priv, int threshold, int hysteresis);
 };
 
 
@@ -2030,7 +2046,16 @@ enum wpa_event_type {
 	 * %wpa_supplicant, this event is used only if the send_eapol() handler
 	 * is used to override the use of l2_packet for EAPOL frame TX.
 	 */
-	EVENT_EAPOL_RX
+	EVENT_EAPOL_RX,
+
+	/**
+	 * EVENT_SIGNAL_CHANGE - Indicate change in signal strength
+	 *
+	 * This event is used to indicate changes in the signal strength
+	 * observed in frames received from the current AP if signal strength
+	 * monitoring has been enabled with signal_monitor().
+	 */
+	EVENT_SIGNAL_CHANGE
 };
 
 
@@ -2402,6 +2427,13 @@ union wpa_event_data {
 		const u8 *data;
 		size_t data_len;
 	} eapol_rx;
+
+	/**
+	 * struct signal_change - Data for EVENT_SIGNAL_CHANGE events
+	 */
+	struct signal_change {
+		int above_threshold;
+	} signal_change;
 };
 
 /**

src/drivers/driver_ndis.c

@@ -3274,5 +3274,6 @@ const struct wpa_driver_ops wpa_driver_ndis_ops = {
 	NULL /* disable_11b_rates */,
 	NULL /* deinit_ap */,
 	NULL /* suspend */,
-	NULL /* resume */
+	NULL /* resume */,
+	NULL /* signal_monitor */
 };

src/drivers/driver_nl80211.c

@@ -859,6 +859,7 @@ static void nl80211_cqm_event(struct wpa_driver_nl80211_data *drv,
 	};
 	struct nlattr *cqm[NL80211_ATTR_CQM_MAX + 1];
 	enum nl80211_cqm_rssi_threshold_event event;
+	union wpa_event_data ed;
 
 	if (tb[NL80211_ATTR_CQM] == NULL ||
 	    nla_parse_nested(cqm, NL80211_ATTR_CQM_MAX, tb[NL80211_ATTR_CQM],
@@ -870,13 +871,21 @@ static void nl80211_cqm_event(struct wpa_driver_nl80211_data *drv,
 	if (cqm[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT] == NULL)
 		return;
 	event = nla_get_u32(cqm[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT]);
+
+	os_memset(&ed, 0, sizeof(ed));
+
 	if (event == NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH) {
 		wpa_printf(MSG_DEBUG, "nl80211: Connection quality monitor "
 			   "event: RSSI high");
+		ed.signal_change.above_threshold = 1;
 	} else if (event == NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW) {
 		wpa_printf(MSG_DEBUG, "nl80211: Connection quality monitor "
 			   "event: RSSI low");
-	}
+		ed.signal_change.above_threshold = 0;
+	} else
+		return;
+
+	wpa_supplicant_event(drv->ctx, EVENT_SIGNAL_CHANGE, &ed);
 }
 
 
@@ -5190,6 +5199,44 @@ static int nl80211_send_ft_action(void *priv, u8 action, const u8 *target_ap,
 }
 
 
+static int nl80211_signal_monitor(void *priv, int threshold, int hysteresis)
+{
+	struct i802_bss *bss = priv;
+	struct wpa_driver_nl80211_data *drv = bss->drv;
+	struct nl_msg *msg, *cqm = NULL;
+
+	wpa_printf(MSG_DEBUG, "nl80211: Signal monitor threshold=%d "
+		   "hysteresis=%d", threshold, hysteresis);
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		return -1;
+
+	genlmsg_put(msg, 0, 0, genl_family_get_id(drv->nl80211), 0,
+		    0, NL80211_CMD_SET_CQM, 0);
+
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, bss->ifindex);
+
+	cqm = nlmsg_alloc();
+	if (cqm == NULL)
+		return -1;
+
+	NLA_PUT_U32(cqm, NL80211_ATTR_CQM_RSSI_THOLD, threshold);
+	NLA_PUT_U32(cqm, NL80211_ATTR_CQM_RSSI_HYST, hysteresis);
+	nla_put_nested(msg, NL80211_ATTR_CQM, cqm);
+
+	if (send_and_recv_msgs(drv, msg, NULL, NULL) == 0)
+		return 0;
+	msg = NULL;
+
+nla_put_failure:
+	if (cqm)
+		nlmsg_free(cqm);
+	nlmsg_free(msg);
+	return -1;
+}
+
+
 const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.name = "nl80211",
 	.desc = "Linux nl80211/cfg80211",
@@ -5249,4 +5296,5 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 	.deinit_ap = wpa_driver_nl80211_deinit_ap,
 	.resume = wpa_driver_nl80211_resume,
 	.send_ft_action = nl80211_send_ft_action,
+	.signal_monitor = nl80211_signal_monitor,
 };

wpa_supplicant/driver_i.h

@@ -466,4 +466,13 @@ static inline void wpa_drv_resume(struct wpa_supplicant *wpa_s)
 		wpa_s->driver->resume(wpa_s->drv_priv);
 }
 
+static inline int wpa_drv_signal_monitor(struct wpa_supplicant *wpa_s,
+					 int threshold, int hysteresis)
+{
+	if (wpa_s->driver->signal_monitor)
+		return wpa_s->driver->signal_monitor(wpa_s->drv_priv,
+						     threshold, hysteresis);
+	return -1;
+}
+
 #endif /* DRIVER_I_H */