diff options
| -rw-r--r-- | src/net/mac.go | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/src/net/mac.go b/src/net/mac.go index 13f505192..ea3b921f0 100644 --- a/src/net/mac.go +++ b/src/net/mac.go @@ -7,3 +7,93 @@ package net 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, EUI-64, or a 20-octet +// IP over InfiniBand link-layer address using one of the following formats: +// 00:00:5e:00:53:01 +// 02:00:5e:10:00:00:00:01 +// 00:00:00:00:fe:80:00:00:00:00:00:00:02:00:5e:10:00:00:00:01 +// 00-00-5e-00-53-01 +// 02-00-5e-10-00-00-00-01 +// 00-00-00-00-fe-80-00-00-00-00-00-00-02-00-5e-10-00-00-00-01 +// 0000.5e00.5301 +// 0200.5e10.0000.0001 +// 0000.0000.fe80.0000.0000.0000.0200.5e10.0000.0001 +func ParseMAC(s string) (hw HardwareAddr, err error) { + if len(s) < 14 { + goto err + } + + if s[2] == ':' || s[2] == '-' { + if (len(s)+1)%3 != 0 { + goto err + } + n := (len(s) + 1) / 3 + if n != 6 && n != 8 && n != 20 { + goto err + } + 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 err + } + x += 3 + } + } else if s[4] == '.' { + if (len(s)+1)%5 != 0 { + goto err + } + n := 2 * (len(s) + 1) / 5 + if n != 6 && n != 8 && n != 20 { + goto err + } + 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 err + } + if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok { + goto err + } + x += 5 + } + } else { + goto err + } + return hw, nil + +err: + return nil, &AddrError{Err: "invalid MAC address", Addr: s} +} + +// xtoi2 converts the next two hex digits of s into a byte. +// If s is longer than 2 bytes then the third byte must be e. +// If the first two bytes of s are not hex digits or the third byte +// does not match e, false is returned. +func xtoi2(s string, e byte) (byte, bool) { + if len(s) > 2 && s[2] != e { + return 0, false + } + n, ei, ok := xtoi(s[:2]) + return byte(n), ok && ei == 2 +} |