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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.
package net
import (
"errors"
"sync"
"time"
)
// BUG(mikio): On NaCl, Plan9 and Solaris, methods and functions
// related to Interface are not implemented.
// BUG(mikio): On DragonFly BSD, NetBSD and OpenBSD, the
// MulticastAddrs method of Interface is not implemented.
var (
errInvalidInterface = errors.New("invalid network interface")
errInvalidInterfaceIndex = errors.New("invalid network interface index")
errInvalidInterfaceName = errors.New("invalid network interface name")
errNoSuchInterface = errors.New("no such network interface")
errNoSuchMulticastInterface = errors.New("no such multicast network interface")
)
// 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, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errInvalidInterface}
}
ifat, err := interfaceAddrTable(ifi)
if err != nil {
err = &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
return ifat, err
}
// MulticastAddrs returns multicast, joined group addresses for
// a specific interface.
func (ifi *Interface) MulticastAddrs() ([]Addr, error) {
if ifi == nil {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errInvalidInterface}
}
ifat, err := interfaceMulticastAddrTable(ifi)
if err != nil {
err = &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
return ifat, err
}
// Interfaces returns a list of the system's network interfaces.
func Interfaces() ([]Interface, error) {
ift, err := interfaceTable(0)
if err != nil {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
if len(ift) != 0 {
zoneCache.update(ift)
}
return ift, nil
}
// InterfaceAddrs returns a list of the system's network interface
// addresses.
func InterfaceAddrs() ([]Addr, error) {
ifat, err := interfaceAddrTable(nil)
if err != nil {
err = &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
return ifat, err
}
// InterfaceByIndex returns the interface specified by index.
func InterfaceByIndex(index int) (*Interface, error) {
if index <= 0 {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errInvalidInterfaceIndex}
}
ift, err := interfaceTable(index)
if err != nil {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
ifi, err := interfaceByIndex(ift, index)
if err != nil {
err = &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
return ifi, err
}
func interfaceByIndex(ift []Interface, index int) (*Interface, error) {
for _, ifi := range ift {
if index == ifi.Index {
return &ifi, nil
}
}
return nil, errNoSuchInterface
}
// InterfaceByName returns the interface specified by name.
func InterfaceByName(name string) (*Interface, error) {
if name == "" {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errInvalidInterfaceName}
}
ift, err := interfaceTable(0)
if err != nil {
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: err}
}
if len(ift) != 0 {
zoneCache.update(ift)
}
for _, ifi := range ift {
if name == ifi.Name {
return &ifi, nil
}
}
return nil, &OpError{Op: "route", Net: "ip+net", Source: nil, Addr: nil, Err: errNoSuchInterface}
}
// An ipv6ZoneCache represents a cache holding partial network
// interface information. It is used for reducing the cost of IPv6
// addressing scope zone resolution.
type ipv6ZoneCache struct {
sync.RWMutex // guard the following
lastFetched time.Time // last time routing information was fetched
toIndex map[string]int // interface name to its index
toName map[int]string // interface index to its name
}
var zoneCache = ipv6ZoneCache{
toIndex: make(map[string]int),
toName: make(map[int]string),
}
func (zc *ipv6ZoneCache) update(ift []Interface) {
zc.Lock()
defer zc.Unlock()
now := time.Now()
if zc.lastFetched.After(now.Add(-60 * time.Second)) {
return
}
zc.lastFetched = now
if len(ift) == 0 {
var err error
if ift, err = interfaceTable(0); err != nil {
return
}
}
zc.toIndex = make(map[string]int, len(ift))
zc.toName = make(map[int]string, len(ift))
for _, ifi := range ift {
zc.toIndex[ifi.Name] = ifi.Index
zc.toName[ifi.Index] = ifi.Name
}
}
func zoneToString(zone int) string {
if zone == 0 {
return ""
}
zoneCache.update(nil)
zoneCache.RLock()
defer zoneCache.RUnlock()
name, ok := zoneCache.toName[zone]
if !ok {
name = uitoa(uint(zone))
}
return name
}
func zoneToInt(zone string) int {
if zone == "" {
return 0
}
zoneCache.update(nil)
zoneCache.RLock()
defer zoneCache.RUnlock()
index, ok := zoneCache.toIndex[zone]
if !ok {
index, _, _ = dtoi(zone)
}
return index
}