netconfig

Documentation

Overview

Package netconfig implements a network configuration watcher, or more accurately an interface to a network configuration watcher. The OS specific implementation implements the Notifier interface below and must be set via the SetNotifier method. No auto-registration mechanism is provided since the OS specific code may use CGO and some applications may prefer to avoid the use of cgo in order to allow for simple cross compilation.

Index

• func GetIPRoutes(defaultOnly bool) []route.IPRoute
• func NotifyChange() (<-chan struct{}, error)
• func SetOSNotifier(n Notifier)
• func Shutdown()
• type Notifier
• type NullNotifier
  • func (n *NullNotifier) GetIPRoutes(defaultOnly bool) []route.IPRoute
  • func (n *NullNotifier) NotifyChange() (<-chan struct{}, error)
  • func (n *NullNotifier) Shutdown()

Examples

• NotifyChange

Functions

func GetIPRoutes

func GetIPRoutes(defaultOnly bool) []route.IPRoute

GetIPRoutes returns all kernel known routes. If defaultOnly is set, only default routes are returned. If SetOSNotifier has not been called then then an empty set of routes will be returned.

func NotifyChange

func NotifyChange() (<-chan struct{}, error)

NotifyChange returns a channel that will be closed when the network configuration changes from the time this function was invoked. If SetOSNotifier has not been called then the channel returned will never be closed since no network changes will ever be detected.

Example

package main

import (
	"fmt"
	"log"

	"v.io/x/lib/netconfig"
	"v.io/x/lib/netconfig/osnetconfig"
)

func main() {
	netconfig.SetOSNotifier(osnetconfig.NewNotifier(0))
	for {
		ch, err := netconfig.NotifyChange()
		if err != nil {
			log.Fatalf("oops: %s", err)
		}
		fmt.Println("Do something to your network.")
		<-ch
		fmt.Println("Network configuration changed.")
	}
}

func SetOSNotifier

func SetOSNotifier(n Notifier)

SetOSNotifier sets a the internal notifier to the one supplied. An existing Notifier will be shutdown.

func Shutdown

func Shutdown()

Shutdown shutdowns the current notifier.

Types

type Notifier

type Notifier interface {
	// NotifyChange returns a channel that will be closed when the network
	// configuration changes from the time this function was invoked.
	//
	// This may provide false positivies, i.e., a network change
	// will cause the channel to be closed but a channel closure
	// may not imply a network change.
	NotifyChange() (<-chan struct{}, error)

	// GetIPRoutes returns all kernel known routes. If defaultOnly is set,
	// only default routes are returned.
	GetIPRoutes(defaultOnly bool) []route.IPRoute

	// Shutdown will shutdown the notifier and close the channel returned
	// by NotifyChange.
	Shutdown()
}

Notifier represents a notifier of network configuration changes and for obtaining current network state.

type NullNotifier

type NullNotifier struct {
	// contains filtered or unexported fields
}

NullNotifier represents a null implementation of Notifier that will never return any notifications or routes. It is provided as a default.

func (*NullNotifier) GetIPRoutes

func (n *NullNotifier) GetIPRoutes(defaultOnly bool) []route.IPRoute

GetIPRoutes implements Notifier.

func (*NullNotifier) NotifyChange

func (n *NullNotifier) NotifyChange() (<-chan struct{}, error)

NotifyChange implements Notifier.

func (*NullNotifier) Shutdown

func (n *NullNotifier) Shutdown()

Shutdown implements Notifier.