1 // Copyright 2011 The Go Authors. 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.
5 // MAC address manipulations
11 const hexDigit = "0123456789abcdef"
13 // A HardwareAddr represents a physical hardware address.
14 type HardwareAddr []byte
16 func (a HardwareAddr) String() string {
20 buf := make([]byte, 0, len(a)*3-1)
23 buf = append(buf, ':')
25 buf = append(buf, hexDigit[b>>4])
26 buf = append(buf, hexDigit[b&0xF])
31 // ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, or EUI-64 using one of the
34 // 01:23:45:67:89:ab:cd:ef
36 // 01-23-45-67-89-ab-cd-ef
38 // 0123.4567.89ab.cdef
39 func ParseMAC(s string) (hw HardwareAddr, err error) {
44 if s[2] == ':' || s[2] == '-' {
45 if (len(s)+1)%3 != 0 {
52 hw = make(HardwareAddr, n)
53 for x, i := 0, 0; i < n; i++ {
55 if hw[i], ok = xtoi2(s[x:], s[2]); !ok {
60 } else if s[4] == '.' {
61 if (len(s)+1)%5 != 0 {
64 n := 2 * (len(s) + 1) / 5
68 hw = make(HardwareAddr, n)
69 for x, i := 0, 0; i < n; i += 2 {
71 if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
74 if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok {
85 return nil, errors.New("invalid MAC address: " + s)