node_net.go raw

   1  // Copyright 2017 Google Inc.  All rights reserved.
   2  // Use of this source code is governed by a BSD-style
   3  // license that can be found in the LICENSE file.
   4  
   5  // +build !js
   6  
   7  package uuid
   8  
   9  import "net"
  10  
  11  var interfaces []net.Interface // cached list of interfaces
  12  
  13  // getHardwareInterface returns the name and hardware address of interface name.
  14  // If name is "" then the name and hardware address of one of the system's
  15  // interfaces is returned.  If no interfaces are found (name does not exist or
  16  // there are no interfaces) then "", nil is returned.
  17  //
  18  // Only addresses of at least 6 bytes are returned.
  19  func getHardwareInterface(name string) (string, []byte) {
  20  	if interfaces == nil {
  21  		var err error
  22  		interfaces, err = net.Interfaces()
  23  		if err != nil {
  24  			return "", nil
  25  		}
  26  	}
  27  	for _, ifs := range interfaces {
  28  		if len(ifs.HardwareAddr) >= 6 && (name == "" || name == ifs.Name) {
  29  			return ifs.Name, ifs.HardwareAddr
  30  		}
  31  	}
  32  	return "", nil
  33  }
  34