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. 4 5 package net 6 7 const hexDigit = "0123456789abcdef" 8 9 // A HardwareAddr represents a physical hardware address. 10 type HardwareAddr []byte 11 12 func (a HardwareAddr) String() string { 13 if len(a) == 0 { 14 return "" 15 } 16 buf := make([]byte, 0, len(a)*3-1) 17 for i, b := range a { 18 if i > 0 { 19 buf = append(buf, ':') 20 } 21 buf = append(buf, hexDigit[b>>4]) 22 buf = append(buf, hexDigit[b&0xF]) 23 } 24 return string(buf) 25 } 26 27 // ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, EUI-64, or a 20-octet 28 // IP over InfiniBand link-layer address using one of the following formats: 29 // 01:23:45:67:89:ab 30 // 01:23:45:67:89:ab:cd:ef 31 // 01:23:45:67:89:ab:cd:ef:00:00:01:23:45:67:89:ab:cd:ef:00:00 32 // 01-23-45-67-89-ab 33 // 01-23-45-67-89-ab-cd-ef 34 // 01-23-45-67-89-ab-cd-ef-00-00-01-23-45-67-89-ab-cd-ef-00-00 35 // 0123.4567.89ab 36 // 0123.4567.89ab.cdef 37 // 0123.4567.89ab.cdef.0000.0123.4567.89ab.cdef.0000 38 func ParseMAC(s string) (hw HardwareAddr, err error) { 39 if len(s) < 14 { 40 goto error 41 } 42 43 if s[2] == ':' || s[2] == '-' { 44 if (len(s)+1)%3 != 0 { 45 goto error 46 } 47 n := (len(s) + 1) / 3 48 if n != 6 && n != 8 && n != 20 { 49 goto error 50 } 51 hw = make(HardwareAddr, n) 52 for x, i := 0, 0; i < n; i++ { 53 var ok bool 54 if hw[i], ok = xtoi2(s[x:], s[2]); !ok { 55 goto error 56 } 57 x += 3 58 } 59 } else if s[4] == '.' { 60 if (len(s)+1)%5 != 0 { 61 goto error 62 } 63 n := 2 * (len(s) + 1) / 5 64 if n != 6 && n != 8 && n != 20 { 65 goto error 66 } 67 hw = make(HardwareAddr, n) 68 for x, i := 0, 0; i < n; i += 2 { 69 var ok bool 70 if hw[i], ok = xtoi2(s[x:x+2], 0); !ok { 71 goto error 72 } 73 if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok { 74 goto error 75 } 76 x += 5 77 } 78 } else { 79 goto error 80 } 81 return hw, nil 82 83 error: 84 return nil, &AddrError{Err: "invalid MAC address", Addr: s} 85 } 86
