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// 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.
// Network interface identification
package net
import (
"bytes"
"errors"
"fmt"
)
var (
errInvalidInterface = errors.New("net: invalid interface")
errInvalidInterfaceIndex = errors.New("net: invalid interface index")
errInvalidInterfaceName = errors.New("net: invalid interface name")
errNoSuchInterface = errors.New("net: no such interface")
errNoSuchMulticastInterface = errors.New("net: no such multicast interface")
)
// A HardwareAddr represents a physical hardware address.
type HardwareAddr []byte
func (a HardwareAddr) String() string {
var buf bytes.Buffer
for i, b := range a {
if i > 0 {
buf.WriteByte(':')
}
fmt.Fprintf(&buf, "%02x", b)
}
return buf.String()
}
// 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)
}
// Interface represents a mapping between network interface name
// and index. It also represents network interface facility
// information.
type Interface struct {
Index int // positive integer that starts at one, zero is never used
MTU int // maximum transmission unit
Name string // e.g., "en0", "lo0", "eth0.100"
HardwareAddr HardwareAddr // IEEE MAC-48, EUI-48 and EUI-64 form
Flags Flags // e.g., FlagUp, FlagLoopback, FlagMulticast
}
type Flags uint
const (
FlagUp Flags = 1 << iota // interface is up
FlagBroadcast // interface supports broadcast access capability
FlagLoopback // interface is a loopback interface
FlagPointToPoint // interface belongs to a point-to-point link
FlagMulticast // interface supports multicast access capability
)
var flagNames = []string{
"up",
"broadcast",
"loopback",
"pointtopoint",
"multicast",
}
func (f Flags) String() string {
s := ""
for i, name := range flagNames {
if f&(1<<uint(i)) != 0 {
if s != "" {
s += "|"
}
s += name
}
}
if s == "" {
s = "0"
}
return s
}
// Addrs returns interface addresses for a specific interface.
func (ifi *Interface) Addrs() ([]Addr, error) {
if ifi == nil {
return nil, errInvalidInterface
}
return interfaceAddrTable(ifi.Index)
}
// MulticastAddrs returns multicast, joined group addresses for
// a specific interface.
func (ifi *Interface) MulticastAddrs() ([]Addr, error) {
if ifi == nil {
return nil, errInvalidInterface
}
return interfaceMulticastAddrTable(ifi.Index)
}
// Interfaces returns a list of the systems's network interfaces.
func Interfaces() ([]Interface, error) {
return interfaceTable(0)
}
// InterfaceAddrs returns a list of the system's network interface
// addresses.
func InterfaceAddrs() ([]Addr, error) {
return interfaceAddrTable(0)
}
// InterfaceByIndex returns the interface specified by index.
func InterfaceByIndex(index int) (*Interface, error) {
if index <= 0 {
return nil, errInvalidInterfaceIndex
}
ift, err := interfaceTable(index)
if err != nil {
return nil, err
}
for _, ifi := range ift {
return &ifi, nil
}
return nil, errNoSuchInterface
}
// InterfaceByName returns the interface specified by name.
func InterfaceByName(name string) (*Interface, error) {
if name == "" {
return nil, errInvalidInterfaceName
}
ift, err := interfaceTable(0)
if err != nil {
return nil, err
}
for _, ifi := range ift {
if name == ifi.Name {
return &ifi, nil
}
}
return nil, errNoSuchInterface
}
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