libgo/go/net/ipraw_test.go

   1 // Copyright 2009 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
   6 // TODO(cw): ListenPacket test, Read() test, ipv6 test &
   7 // Dial()/Listen() level tests
   8
   9 package net
  10
  11 import (
  12         "bytes"
  13         "flag"
  14         "os"
  15         "testing"
  16 )
  17
  18 const ICMP_ECHO_REQUEST = 8
  19 const ICMP_ECHO_REPLY = 0
  20
  21 // returns a suitable 'ping request' packet, with id & seq and a
  22 // payload length of pktlen
  23 func makePingRequest(id, seq, pktlen int, filler []byte) []byte {
  24         p := make([]byte, pktlen)
  25         copy(p[8:], bytes.Repeat(filler, (pktlen-8)/len(filler)+1))
  26
  27         p[0] = ICMP_ECHO_REQUEST // type
  28         p[1] = 0                 // code
  29         p[2] = 0                 // cksum
  30         p[3] = 0                 // cksum
  31         p[4] = uint8(id >> 8)    // id
  32         p[5] = uint8(id & 0xff)  // id
  33         p[6] = uint8(seq >> 8)   // sequence
  34         p[7] = uint8(seq & 0xff) // sequence
  35
  36         // calculate icmp checksum
  37         cklen := len(p)
  38         s := uint32(0)
  39         for i := 0; i < (cklen - 1); i += 2 {
  40                 s += uint32(p[i+1])<<8 | uint32(p[i])
  41         }
  42         if cklen&1 == 1 {
  43                 s += uint32(p[cklen-1])
  44         }
  45         s = (s >> 16) + (s & 0xffff)
  46         s = s + (s >> 16)
  47
  48         // place checksum back in header; using ^= avoids the
  49         // assumption the checksum bytes are zero
  50         p[2] ^= uint8(^s & 0xff)
  51         p[3] ^= uint8(^s >> 8)
  52
  53         return p
  54 }
  55
  56 func parsePingReply(p []byte) (id, seq int) {
  57         id = int(p[4])<<8 | int(p[5])
  58         seq = int(p[6])<<8 | int(p[7])
  59         return
  60 }
  61
  62 var srchost = flag.String("srchost", "", "Source of the ICMP ECHO request")
  63 var dsthost = flag.String("dsthost", "localhost", "Destination for the ICMP ECHO request")
  64
  65 // test (raw) IP socket using ICMP
  66 func TestICMP(t *testing.T) {
  67         if os.Getuid() != 0 {
  68                 t.Logf("test disabled; must be root")
  69                 return
  70         }
  71
  72         var laddr *IPAddr
  73         if *srchost != "" {
  74                 laddr, err := ResolveIPAddr(*srchost)
  75                 if err != nil {
  76                         t.Fatalf(`net.ResolveIPAddr("%v") = %v, %v`, *srchost, laddr, err)
  77                 }
  78         }
  79
  80         raddr, err := ResolveIPAddr(*dsthost)
  81         if err != nil {
  82                 t.Fatalf(`net.ResolveIPAddr("%v") = %v, %v`, *dsthost, raddr, err)
  83         }
  84
  85         c, err := ListenIP("ip4:icmp", laddr)
  86         if err != nil {
  87                 t.Fatalf(`net.ListenIP("ip4:icmp", %v) = %v, %v`, *srchost, c, err)
  88         }
  89
  90         sendid := os.Getpid() & 0xffff
  91         const sendseq = 61455
  92         const pingpktlen = 128
  93         sendpkt := makePingRequest(sendid, sendseq, pingpktlen, []byte("Go Go Gadget Ping!!!"))
  94
  95         n, err := c.WriteToIP(sendpkt, raddr)
  96         if err != nil || n != pingpktlen {
  97                 t.Fatalf(`net.WriteToIP(..., %v) = %v, %v`, raddr, n, err)
  98         }
  99
 100         c.SetTimeout(100e6)
 101         resp := make([]byte, 1024)
 102         for {
 103                 n, from, err := c.ReadFrom(resp)
 104                 if err != nil {
 105                         t.Fatalf(`ReadFrom(...) = %v, %v, %v`, n, from, err)
 106                 }
 107                 if resp[0] != ICMP_ECHO_REPLY {
 108                         continue
 109                 }
 110                 rcvid, rcvseq := parsePingReply(resp)
 111                 if rcvid != sendid || rcvseq != sendseq {
 112                         t.Fatalf(`Ping reply saw id,seq=0x%x,0x%x (expected 0x%x, 0x%x)`, rcvid, rcvseq, sendid, sendseq)
 113                 }
 114                 return
 115         }
 116         t.Fatalf("saw no ping return")
 117 }