Add support for driver command to update roaming policy

The network block bssid parameter can be used to force a specific BSS to
be used for a connection. It is also possible to modify this parameter
during an association. Previously, that did not result in any
notification to the driver which was somewhat problematic with drivers
that take care of BSS selection. Add a new mechanism to allow
wpa_supplicant to provide a driver update if the bssid parameter change
for the current connection modifies roaming policy (roaming
allowed/disallowed within ESS).

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/drivers/driver.h

@@ -2804,6 +2804,22 @@ struct wpa_driver_ops {
 	 */
 	int (*status)(void *priv, char *buf, size_t buflen);
 
+	/**
+	 * roaming - Set roaming policy for driver-based BSS selection
+	 * @priv: Private driver interface data
+	 * @allowed: Whether roaming within ESS is allowed
+	 * @bssid: Forced BSSID if roaming is disabled or %NULL if not set
+	 * Returns: Length of written status information or -1 on failure
+	 *
+	 * This optional callback can be used to update roaming policy from the
+	 * associate() command (bssid being set there indicates that the driver
+	 * should not roam before getting this roaming() call to allow roaming.
+	 * If the driver does not indicate WPA_DRIVER_FLAGS_BSS_SELECTION
+	 * capability, roaming policy is handled within wpa_supplicant and there
+	 * is no need to implement or react to this callback.
+	 */
+	int (*roaming)(void *priv, int allowed, const u8 *bssid);
+
 #ifdef CONFIG_MACSEC
 	int (*macsec_init)(void *priv, struct macsec_init_params *params);
 

wpa_supplicant/ctrl_iface.c

@@ -2564,9 +2564,10 @@ static int wpa_supplicant_ctrl_iface_update_network(
 static int wpa_supplicant_ctrl_iface_set_network(
 	struct wpa_supplicant *wpa_s, char *cmd)
 {
-	int id;
+	int id, ret, prev_bssid_set;
 	struct wpa_ssid *ssid;
 	char *name, *value;
+	u8 prev_bssid[ETH_ALEN];
 
 	/* cmd: "<network id> <variable name> <value>" */
 	name = os_strchr(cmd, ' ');
@@ -2592,8 +2593,15 @@ static int wpa_supplicant_ctrl_iface_set_network(
 		return -1;
 	}
 
-	return wpa_supplicant_ctrl_iface_update_network(wpa_s, ssid, name,
-							value);
+	prev_bssid_set = ssid->bssid_set;
+	os_memcpy(prev_bssid, ssid->bssid, ETH_ALEN);
+	ret = wpa_supplicant_ctrl_iface_update_network(wpa_s, ssid, name,
+						       value);
+	if (ret == 0 &&
+	    (ssid->bssid_set != prev_bssid_set ||
+	     os_memcmp(ssid->bssid, prev_bssid, ETH_ALEN) != 0))
+		wpas_notify_network_bssid_set_changed(wpa_s, ssid);
+	return ret;
 }
 
 

wpa_supplicant/driver_i.h

@@ -632,6 +632,14 @@ static inline int wpa_drv_vendor_cmd(struct wpa_supplicant *wpa_s,
 					 data, data_len, buf);
 }
 
+static inline int wpa_drv_roaming(struct wpa_supplicant *wpa_s, int allowed,
+				  const u8 *bssid)
+{
+	if (!wpa_s->driver->roaming)
+		return -1;
+	return wpa_s->driver->roaming(wpa_s->drv_priv, allowed, bssid);
+}
+
 
 #ifdef CONFIG_MACSEC
 

wpa_supplicant/notify.c

@@ -633,3 +633,18 @@ void wpas_notify_eap_status(struct wpa_supplicant *wpa_s, const char *status,
 		     "status='%s' parameter='%s'",
 		     status, parameter);
 }
+
+
+void wpas_notify_network_bssid_set_changed(struct wpa_supplicant *wpa_s,
+					   struct wpa_ssid *ssid)
+{
+	if (wpa_s->current_ssid != ssid)
+		return;
+
+	wpa_dbg(wpa_s, MSG_DEBUG,
+		"Network bssid config changed for the current network - within-ESS roaming %s",
+		ssid->bssid_set ? "disabled" : "enabled");
+
+	wpa_drv_roaming(wpa_s, !ssid->bssid_set,
+			ssid->bssid_set ? ssid->bssid : NULL);
+}

wpa_supplicant/notify.h

@@ -128,5 +128,7 @@ void wpas_notify_preq(struct wpa_supplicant *wpa_s,
 		      const u8 *ie, size_t ie_len, u32 ssi_signal);
 void wpas_notify_eap_status(struct wpa_supplicant *wpa_s, const char *status,
 			    const char *parameter);
+void wpas_notify_network_bssid_set_changed(struct wpa_supplicant *wpa_s,
+					   struct wpa_ssid *ssid);
 
 #endif /* NOTIFY_H */