Retro68/gcc/libgo/go/net/mac.go
2014-09-21 19:33:12 +02:00

87 lines
1.7 KiB
Go

// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// MAC address manipulations
package net
import "errors"
const hexDigit = "0123456789abcdef"
// A HardwareAddr represents a physical hardware address.
type HardwareAddr []byte
func (a HardwareAddr) String() string {
if len(a) == 0 {
return ""
}
buf := make([]byte, 0, len(a)*3-1)
for i, b := range a {
if i > 0 {
buf = append(buf, ':')
}
buf = append(buf, hexDigit[b>>4])
buf = append(buf, hexDigit[b&0xF])
}
return string(buf)
}
// ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, or EUI-64 using one of the
// following formats:
// 01:23:45:67:89:ab
// 01:23:45:67:89:ab:cd:ef
// 01-23-45-67-89-ab
// 01-23-45-67-89-ab-cd-ef
// 0123.4567.89ab
// 0123.4567.89ab.cdef
func ParseMAC(s string) (hw HardwareAddr, err error) {
if len(s) < 14 {
goto error
}
if s[2] == ':' || s[2] == '-' {
if (len(s)+1)%3 != 0 {
goto error
}
n := (len(s) + 1) / 3
if n != 6 && n != 8 {
goto error
}
hw = make(HardwareAddr, n)
for x, i := 0, 0; i < n; i++ {
var ok bool
if hw[i], ok = xtoi2(s[x:], s[2]); !ok {
goto error
}
x += 3
}
} else if s[4] == '.' {
if (len(s)+1)%5 != 0 {
goto error
}
n := 2 * (len(s) + 1) / 5
if n != 6 && n != 8 {
goto error
}
hw = make(HardwareAddr, n)
for x, i := 0, 0; i < n; i += 2 {
var ok bool
if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
goto error
}
if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok {
goto error
}
x += 5
}
} else {
goto error
}
return hw, nil
error:
return nil, errors.New("invalid MAC address: " + s)
}