example_test.go

Documentation: golang.org/x/net/icmp

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package icmp_test
     6  
     7  import (
     8  	"log"
     9  	"net"
    10  	"os"
    11  	"runtime"
    12  
    13  	"golang.org/x/net/icmp"
    14  	"golang.org/x/net/ipv6"
    15  )
    16  
    17  func ExamplePacketConn_nonPrivilegedPing() {
    18  	switch runtime.GOOS {
    19  	case "darwin", "ios":
    20  	case "linux":
    21  		log.Println("you may need to adjust the net.ipv4.ping_group_range kernel state")
    22  	default:
    23  		log.Println("not supported on", runtime.GOOS)
    24  		return
    25  	}
    26  
    27  	c, err := icmp.ListenPacket("udp6", "fe80::1%en0")
    28  	if err != nil {
    29  		log.Fatal(err)
    30  	}
    31  	defer c.Close()
    32  
    33  	wm := icmp.Message{
    34  		Type: ipv6.ICMPTypeEchoRequest, Code: 0,
    35  		Body: &icmp.Echo{
    36  			ID: os.Getpid() & 0xffff, Seq: 1,
    37  			Data: []byte("HELLO-R-U-THERE"),
    38  		},
    39  	}
    40  	wb, err := wm.Marshal(nil)
    41  	if err != nil {
    42  		log.Fatal(err)
    43  	}
    44  	if _, err := c.WriteTo(wb, &net.UDPAddr{IP: net.ParseIP("ff02::1"), Zone: "en0"}); err != nil {
    45  		log.Fatal(err)
    46  	}
    47  
    48  	rb := make([]byte, 1500)
    49  	n, peer, err := c.ReadFrom(rb)
    50  	if err != nil {
    51  		log.Fatal(err)
    52  	}
    53  	rm, err := icmp.ParseMessage(58, rb[:n])
    54  	if err != nil {
    55  		log.Fatal(err)
    56  	}
    57  	switch rm.Type {
    58  	case ipv6.ICMPTypeEchoReply:
    59  		log.Printf("got reflection from %v", peer)
    60  	default:
    61  		log.Printf("got %+v; want echo reply", rm)
    62  	}
    63  }
    64
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