source: code/trunk/vendor/github.com/google/uuid/node_net.go@ 822

// Copyright 2017 Google Inc.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build !js

package uuid

import "net"

var interfaces []net.Interface // cached list of interfaces

// getHardwareInterface returns the name and hardware address of interface name.
// If name is "" then the name and hardware address of one of the system's
// interfaces is returned.  If no interfaces are found (name does not exist or
// there are no interfaces) then "", nil is returned.
//
// Only addresses of at least 6 bytes are returned.
func getHardwareInterface(name string) (string, []byte) {
        if interfaces == nil {
                var err error
                interfaces, err = net.Interfaces()
                if err != nil {
                        return "", nil
                }
        }
        for _, ifs := range interfaces {
                if len(ifs.HardwareAddr) >= 6 && (name == "" || name == ifs.Name) {
                        return ifs.Name, ifs.HardwareAddr
                }
        }
        return "", nil
}