android_icmp_ping.go

package main

import (
	"errors"
	"fmt"
	"log"
	"net"
	"os"
	"time"

	"golang.org/x/mobile/app"
	"golang.org/x/net/icmp"
	"golang.org/x/net/ipv4"
)

var addresses = []string{
	"206.189.243.162:443",
	"35.188.19.210:443",
	"47.91.156.93:443",
}

const ProtocolICMP int = 1

func Ping(address string) error {
	//c, err := icmp.ListenPacket("udp4", "0.0.0.0")
	c, err := icmp.ListenPacket("ip4:icmp", "0.0.0.0")
	if err != nil {
		return err
	}
	defer c.Close()

	// Resolve any DNS (if used) and get the real IP of the target
	dst, err := net.ResolveIPAddr("ip4", address)
	if err != nil {
		return err
	}

	// Make a new ICMP message
	m := icmp.Message{
		Type: ipv4.ICMPTypeEcho, Code: 0,
		Body: &icmp.Echo{
			ID: os.Getpid() & 0xffff, Seq: 1, //<< uint(seq), // TODO
			Data: []byte(""),
		},
	}
	b, err := m.Marshal(nil)
	if err != nil {
		return err
	}

	// Send it
	log.Println("Dst:", dst)
	n, err := c.WriteTo(b, dst)
	if err != nil {
		return err
	} else if n != len(b) {
		return errors.New(fmt.Sprintf("got %v; want %v", n, len(b)))
	}

	// Wait for a reply
	reply := make([]byte, 1500)
	err = c.SetReadDeadline(time.Now().Add(10 * time.Second))
	if err != nil {
		return err
	}
	n, peer, err := c.ReadFrom(reply)
	if err != nil {
		return err
	}

	// Pack it up boys, we're done here
	rm, err := icmp.ParseMessage(ProtocolICMP, reply[:n])
	if err != nil {
		return err
	}
	switch rm.Type {
	case ipv4.ICMPTypeEchoReply:
		return nil
	default:
		return errors.New(fmt.Sprintf("got %+v, wanted echo reply from %v", rm, peer))
	}
}

func main() {
	app.Main(appMain)
}

func appMain(a app.App) {
	log.SetPrefix("ICMP_PING: ")
	var i int
	for i = 0; i < len(addresses); i++ {
		err := Ping(addresses[i])
		if err != nil {
			log.Print("Err:", err)
		}
	}
}