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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.
package net
import (
"bytes"
"os"
"syscall"
"testing"
"time"
)
var icmpTests = []struct {
net string
laddr string
raddr string
ipv6 bool // test with underlying AF_INET6 socket
}{
{"ip4:icmp", "", "127.0.0.1", false},
{"ip6:icmp", "", "::1", true},
}
func TestICMP(t *testing.T) {
if os.Getuid() != 0 {
t.Logf("test disabled; must be root")
return
}
seqnum := 61455
for _, tt := range icmpTests {
if tt.ipv6 && !supportsIPv6 {
continue
}
id := os.Getpid() & 0xffff
seqnum++
echo := newICMPEchoRequest(tt.net, id, seqnum, 128, []byte("Go Go Gadget Ping!!!"))
exchangeICMPEcho(t, tt.net, tt.laddr, tt.raddr, echo)
}
}
func exchangeICMPEcho(t *testing.T, net, laddr, raddr string, echo []byte) {
c, err := ListenPacket(net, laddr)
if err != nil {
t.Errorf("ListenPacket(%q, %q) failed: %v", net, laddr, err)
return
}
c.SetDeadline(time.Now().Add(100 * time.Millisecond))
defer c.Close()
ra, err := ResolveIPAddr(net, raddr)
if err != nil {
t.Errorf("ResolveIPAddr(%q, %q) failed: %v", net, raddr, err)
return
}
waitForReady := make(chan bool)
go icmpEchoTransponder(t, net, raddr, waitForReady)
<-waitForReady
_, err = c.WriteTo(echo, ra)
if err != nil {
t.Errorf("WriteTo failed: %v", err)
return
}
reply := make([]byte, 256)
for {
_, _, err := c.ReadFrom(reply)
if err != nil {
t.Errorf("ReadFrom failed: %v", err)
return
}
switch c.(*IPConn).fd.family {
case syscall.AF_INET:
if reply[0] != ICMP4_ECHO_REPLY {
continue
}
case syscall.AF_INET6:
if reply[0] != ICMP6_ECHO_REPLY {
continue
}
}
xid, xseqnum := parseICMPEchoReply(echo)
rid, rseqnum := parseICMPEchoReply(reply)
if rid != xid || rseqnum != xseqnum {
t.Errorf("ID = %v, Seqnum = %v, want ID = %v, Seqnum = %v", rid, rseqnum, xid, xseqnum)
return
}
break
}
}
func icmpEchoTransponder(t *testing.T, net, raddr string, waitForReady chan bool) {
c, err := Dial(net, raddr)
if err != nil {
waitForReady <- true
t.Errorf("Dial(%q, %q) failed: %v", net, raddr, err)
return
}
c.SetDeadline(time.Now().Add(100 * time.Millisecond))
defer c.Close()
waitForReady <- true
echo := make([]byte, 256)
var nr int
for {
nr, err = c.Read(echo)
if err != nil {
t.Errorf("Read failed: %v", err)
return
}
switch c.(*IPConn).fd.family {
case syscall.AF_INET:
if echo[0] != ICMP4_ECHO_REQUEST {
continue
}
case syscall.AF_INET6:
if echo[0] != ICMP6_ECHO_REQUEST {
continue
}
}
break
}
switch c.(*IPConn).fd.family {
case syscall.AF_INET:
echo[0] = ICMP4_ECHO_REPLY
case syscall.AF_INET6:
echo[0] = ICMP6_ECHO_REPLY
}
_, err = c.Write(echo[:nr])
if err != nil {
t.Errorf("Write failed: %v", err)
return
}
}
const (
ICMP4_ECHO_REQUEST = 8
ICMP4_ECHO_REPLY = 0
ICMP6_ECHO_REQUEST = 128
ICMP6_ECHO_REPLY = 129
)
func newICMPEchoRequest(net string, id, seqnum, msglen int, filler []byte) []byte {
afnet, _, _ := parseDialNetwork(net)
switch afnet {
case "ip4":
return newICMPv4EchoRequest(id, seqnum, msglen, filler)
case "ip6":
return newICMPv6EchoRequest(id, seqnum, msglen, filler)
}
return nil
}
func newICMPv4EchoRequest(id, seqnum, msglen int, filler []byte) []byte {
b := newICMPInfoMessage(id, seqnum, msglen, filler)
b[0] = ICMP4_ECHO_REQUEST
// calculate ICMP checksum
cklen := len(b)
s := uint32(0)
for i := 0; i < cklen-1; i += 2 {
s += uint32(b[i+1])<<8 | uint32(b[i])
}
if cklen&1 == 1 {
s += uint32(b[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
b[2] ^= uint8(^s & 0xff)
b[3] ^= uint8(^s >> 8)
return b
}
func newICMPv6EchoRequest(id, seqnum, msglen int, filler []byte) []byte {
b := newICMPInfoMessage(id, seqnum, msglen, filler)
b[0] = ICMP6_ECHO_REQUEST
return b
}
func newICMPInfoMessage(id, seqnum, msglen int, filler []byte) []byte {
b := make([]byte, msglen)
copy(b[8:], bytes.Repeat(filler, (msglen-8)/len(filler)+1))
b[0] = 0 // type
b[1] = 0 // code
b[2] = 0 // checksum
b[3] = 0 // checksum
b[4] = uint8(id >> 8) // identifier
b[5] = uint8(id & 0xff) // identifier
b[6] = uint8(seqnum >> 8) // sequence number
b[7] = uint8(seqnum & 0xff) // sequence number
return b
}
func parseICMPEchoReply(b []byte) (id, seqnum int) {
id = int(b[4])<<8 | int(b[5])
seqnum = int(b[6])<<8 | int(b[7])
return
}
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