forked from snapcore/snapd
/
metered.go
65 lines (55 loc) · 2.07 KB
/
metered.go
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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2018 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package netutil
import (
"fmt"
"github.com/godbus/dbus"
"github.com/snapcore/snapd/logger"
)
const (
// https://developer.gnome.org/NetworkManager/stable/nm-dbus-types.html#NMMetered
NetworkManagerMeteredUnknown = 0
NetworkManagerMeteredYes = 1
NetworkManagerMeteredNo = 2
NetworkManagerMeteredGuessYes = 3
NetworkManagerMeteredGuessNo = 4
)
// IsOnMeteredConnection checks whether the current default network connection
// is metered. If the state can not be determined, returns false and an error.
func IsOnMeteredConnection() (bool, error) {
// obtain a shared connection to system bus, no need to close it
conn, err := dbus.SystemBus()
if err != nil {
return false, fmt.Errorf("cannot connect to system bus: %v", err)
}
return isNMOnMetered(conn)
}
func isNMOnMetered(conn *dbus.Conn) (bool, error) {
nmObj := conn.Object("org.freedesktop.NetworkManager", "/org/freedesktop/NetworkManager")
// https://developer.gnome.org/NetworkManager/stable/gdbus-org.freedesktop.NetworkManager.html
dbusV, err := nmObj.GetProperty("org.freedesktop.NetworkManager.Metered")
if err != nil {
return false, err
}
v, ok := dbusV.Value().(uint32)
if !ok {
return false, fmt.Errorf("network manager returned invalid value for metering verification: %s", dbusV)
}
logger.Debugf("metered state reported by NetworkManager: %s", dbusV)
return v == NetworkManagerMeteredGuessYes || v == NetworkManagerMeteredYes, nil
}