git.sr.ht/~pingoo/stdx@v0.0.0-20240218134121-094174641f6e/uuid/node_net.go (about)

     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  }