DBus: Add "Roam" command support

Add D-Bus interface for ROAM command, imitating the existing wpa_cli
command.

Chromium OS has been carrying a form of this patch for a very long time.
I've cleaned it up a bit and documented it.

Signed-off-by: Brian Norris <briannorris@chromium.org>

doc/dbus.doxygen

@@ -322,6 +322,24 @@ fi.w1.wpa_supplicant1.CreateInterface.
 	</dl>
       </li>
 
+      <li>
+	<h3>Roam ( s : addr ) --> nothing</h3>
+	<p>Initiate a roam to another BSS within the current ESS.</p>
+	<h4>Possible errors</h4>
+	<dl>
+	  <dt>fi.w1.wpa_supplicant1.InvalidArgs</dt>
+	  <dd>Missing address argument.</dd>
+	  <dt>fi.w1.wpa_supplicant1.InvalidArgs</dt>
+	  <dd>Invalid hardware address format.</dd>
+	  <dt>fi.w1.wpa_supplicant1.InvalidArgs</dt>
+	  <dd>Target BSS not found.</dd>
+	  <dt>fi.w1.wpa_supplicant1.NotConnected</dt>
+	  <dd>Interface is not connected to any network.</dd>
+	  <dt>fi.w1.wpa_supplicant1.UnknownError</dt>
+	  <dd>Scan processing was not included in the build.</dd>
+	</dl>
+      </li>
+
       <li>
 	<h3>AddBlob ( s : name, ay : data ) --> nothing</h3>
 	<p>Adds a blob to the interface.</p>

wpa_supplicant/dbus/dbus_new.c

@@ -3212,6 +3212,14 @@ static const struct wpa_dbus_method_desc wpas_dbus_interface_methods[] = {
 		  END_ARGS
 	  }
 	},
+	{ "Roam", WPAS_DBUS_NEW_IFACE_INTERFACE,
+	  (WPADBusMethodHandler) wpas_dbus_handler_roam,
+	  {
+		  { "addr", "s", ARG_IN },
+		  END_ARGS
+	  }
+	},
+
 #ifndef CONFIG_NO_CONFIG_BLOBS
 	{ "AddBlob", WPAS_DBUS_NEW_IFACE_INTERFACE,
 	  (WPADBusMethodHandler) wpas_dbus_handler_add_blob,

wpa_supplicant/dbus/dbus_new_handlers.c

@@ -1976,6 +1976,55 @@ out:
 }
 
 
+/**
+ * wpas_dbus_handler_roam - Initiate a roam to another BSS within the ESS
+ * @message: Pointer to incoming dbus message
+ * @wpa_s: wpa_supplicant structure for a network interface
+ * Returns: NULL on success or dbus error on failure
+ *
+ * Handler function for "Roam" method call of network interface.
+ */
+DBusMessage * wpas_dbus_handler_roam(DBusMessage *message,
+				     struct wpa_supplicant *wpa_s)
+{
+#ifdef CONFIG_NO_SCAN_PROCESSING
+	return wpas_dbus_error_unknown_error(message,
+					     "scan processing not included");
+#else /* CONFIG_NO_SCAN_PROCESSING */
+	u8 bssid[ETH_ALEN];
+	struct wpa_bss *bss;
+	struct wpa_ssid *ssid = wpa_s->current_ssid;
+	char *addr;
+
+	if (!dbus_message_get_args(message, NULL, DBUS_TYPE_STRING, &addr,
+				   DBUS_TYPE_INVALID))
+		return wpas_dbus_error_invalid_args(message, NULL);
+
+	if (hwaddr_aton(addr, bssid))
+		return wpas_dbus_error_invalid_args(
+			message, "Invalid hardware address format");
+
+	wpa_printf(MSG_DEBUG, "dbus: Roam " MACSTR, MAC2STR(bssid));
+
+	if (!ssid)
+		return dbus_message_new_error(
+			message, WPAS_DBUS_ERROR_NOT_CONNECTED,
+			"This interface is not connected");
+
+	bss = wpa_bss_get(wpa_s, bssid, ssid->ssid, ssid->ssid_len);
+	if (!bss) {
+		wpa_printf(MSG_DEBUG, "dbus: Roam: Target BSS not found");
+		return wpas_dbus_error_invalid_args(
+			message, "Target BSS not found");
+	}
+
+	wpa_s->reassociate = 1;
+	wpa_supplicant_connect(wpa_s, bss, ssid);
+
+	return NULL;
+#endif /* CONFIG_NO_SCAN_PROCESSING */
+}
+
 #ifndef CONFIG_NO_CONFIG_BLOBS
 
 /**

wpa_supplicant/dbus/dbus_new_handlers.h

@@ -117,6 +117,9 @@ DBusMessage * wpas_dbus_handler_select_network(DBusMessage *message,
 DBusMessage * wpas_dbus_handler_network_reply(DBusMessage *message,
 					      struct wpa_supplicant *wpa_s);
 
+DBusMessage * wpas_dbus_handler_roam(DBusMessage *message,
+				     struct wpa_supplicant *wpa_s);
+
 DBusMessage * wpas_dbus_handler_add_blob(DBusMessage *message,
 					 struct wpa_supplicant *wpa_s);