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// Copyright 2009 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.
// TODO(cw): ListenPacket test, Read() test, ipv6 test &
// Dial()/Listen() level tests
package net
import (
"bytes"
"flag"
"os"
"testing"
)
const ICMP_ECHO_REQUEST = 8
const ICMP_ECHO_REPLY = 0
// returns a suitable 'ping request' packet, with id & seq and a
// payload length of pktlen
func makePingRequest(id, seq, pktlen int, filler []byte) []byte {
p := make([]byte, pktlen)
copy(p[8:], bytes.Repeat(filler, (pktlen-8)/len(filler)+1))
p[0] = ICMP_ECHO_REQUEST // type
p[1] = 0 // code
p[2] = 0 // cksum
p[3] = 0 // cksum
p[4] = uint8(id >> 8) // id
p[5] = uint8(id & 0xff) // id
p[6] = uint8(seq >> 8) // sequence
p[7] = uint8(seq & 0xff) // sequence
// calculate icmp checksum
cklen := len(p)
s := uint32(0)
for i := 0; i < (cklen - 1); i += 2 {
s += uint32(p[i+1])<<8 | uint32(p[i])
}
if cklen&1 == 1 {
s += uint32(p[cklen-1])
}
s = (s >> 16) + (s & 0xffff)
s = s + (s >> 16)
// place checksum back in header; using ^= avoids the
// assumption the checksum bytes are zero
p[2] ^= uint8(^s & 0xff)
p[3] ^= uint8(^s >> 8)
return p
}
func parsePingReply(p []byte) (id, seq int) {
id = int(p[4])<<8 | int(p[5])
seq = int(p[6])<<8 | int(p[7])
return
}
var srchost = flag.String("srchost", "", "Source of the ICMP ECHO request")
var dsthost = flag.String("dsthost", "localhost", "Destination for the ICMP ECHO request")
// test (raw) IP socket using ICMP
func TestICMP(t *testing.T) {
if os.Getuid() != 0 {
t.Logf("test disabled; must be root")
return
}
var laddr *IPAddr
if *srchost != "" {
laddr, err := ResolveIPAddr(*srchost)
if err != nil {
t.Fatalf(`net.ResolveIPAddr("%v") = %v, %v`, *srchost, laddr, err)
}
}
raddr, err := ResolveIPAddr(*dsthost)
if err != nil {
t.Fatalf(`net.ResolveIPAddr("%v") = %v, %v`, *dsthost, raddr, err)
}
c, err := ListenIP("ip4:icmp", laddr)
if err != nil {
t.Fatalf(`net.ListenIP("ip4:icmp", %v) = %v, %v`, *srchost, c, err)
}
sendid := os.Getpid() & 0xffff
const sendseq = 61455
const pingpktlen = 128
sendpkt := makePingRequest(sendid, sendseq, pingpktlen, []byte("Go Go Gadget Ping!!!"))
n, err := c.WriteToIP(sendpkt, raddr)
if err != nil || n != pingpktlen {
t.Fatalf(`net.WriteToIP(..., %v) = %v, %v`, raddr, n, err)
}
c.SetTimeout(100e6)
resp := make([]byte, 1024)
for {
n, from, err := c.ReadFrom(resp)
if err != nil {
t.Fatalf(`ReadFrom(...) = %v, %v, %v`, n, from, err)
}
if resp[0] != ICMP_ECHO_REPLY {
continue
}
rcvid, rcvseq := parsePingReply(resp)
if rcvid != sendid || rcvseq != sendseq {
t.Fatalf(`Ping reply saw id,seq=0x%x,0x%x (expected 0x%x, 0x%x)`, rcvid, rcvseq, sendid, sendseq)
}
return
}
t.Fatalf("saw no ping return")
}
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