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 && n != 20 {
			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
			}

	}
	return n, i, true
}

// 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
}

			if ifi == nil || name == ifi.Name {
				// The Linux kernel puts the IP
				// address in /proc/net/igmp in native
				// endianness.
				for i := 0; i+1 < len(f[0]); i += 2 {
					b[i/2], _ = xtoi2(f[0][i:i+2], 0)
				}
				i := *(*uint32)(unsafe.Pointer(&b[:4][0]))
				ifma := &IPAddr{IP: IPv4(byte(i>>24), byte(i>>16), byte(i>>8), byte(i))}
				ifmat = append(ifmat, ifma)
			}
		}
	}
	return ifmat

		}

		if len(line) > 0 && len(line)%2 == 0 {
			ifc.HardwareAddr = make([]byte, len(line)/2)
			var ok bool
			for i := range ifc.HardwareAddr {
				j := (i + 1) * 2
				ifc.HardwareAddr[i], ok = xtoi2(line[i*2:j], 0)
				if !ok {
					ifc.HardwareAddr = ifc.HardwareAddr[:i]
					break
				}
			}
		}

		ifc.Flags = FlagUp | FlagRunning | FlagBroadcast | FlagMulticast
	} else {