// runDatagramTransponder transmits ICMP for IPv4 datagrams to the
// loopback address or interface and captures the response datagrams
// from the protocol stack within the kernel.
func runDatagramTransponder(t *testing.T, c *ipv4.RawConn, wb []byte, src, dst net.Addr) {
	cf := ipv4.FlagTTL | ipv4.FlagDst | ipv4.FlagInterface
	rb := make([]byte, ipv4.HeaderLen+len(wb))
	for i, toggle := range []bool{true, false, true} {
		if err := c.SetControlMessage(cf, toggle); err != nil {
			t.Fatalf("ipv4.RawConn.SetControlMessage failed: %v", err)
		}
		wh := &ipv4.Header{}
		wh.Version = ipv4.Version
		wh.Len = ipv4.HeaderLen
		wh.TOS = i + 1
		wh.TotalLen = ipv4.HeaderLen + len(wb)
		wh.TTL = i + 1
		wh.Protocol = 1
		if src != nil {
			wh.Src = src.(*net.IPAddr).IP
		}
		if dst != nil {
			wh.Dst = dst.(*net.IPAddr).IP
		}
		c.SetDeadline(time.Now().Add(100 * time.Millisecond))
		if err := c.Write(wh, wb, nil); err != nil {
			t.Fatalf("ipv4.RawConn.Write failed: %v", err)
		}
		rh, _, cm, err := c.Read(rb)
		if err != nil {
			t.Fatalf("ipv4.RawConn.Read failed: %v", err)
		}
		t.Logf("rcvd cmsg: %v", cm.String())
		t.Logf("rcvd hdr: %v", rh.String())
	}
}
Beispiel #2
0
// writeThenReadDatagram transmits ICMP for IPv4 datagrams to the
// loopback address or interface and captures the response datagrams
// from the protocol stack within the kernel.
func writeThenReadDatagram(t *testing.T, i int, c *ipv4.RawConn, wb []byte, src, dst net.Addr) []byte {
	rb := make([]byte, ipv4.HeaderLen+len(wb))
	wh := &ipv4.Header{
		Version:  ipv4.Version,
		Len:      ipv4.HeaderLen,
		TOS:      i + 1,
		TotalLen: ipv4.HeaderLen + len(wb),
		TTL:      i + 1,
		Protocol: 1,
	}
	if src != nil {
		wh.Src = src.(*net.IPAddr).IP
	}
	if dst != nil {
		wh.Dst = dst.(*net.IPAddr).IP
	}
	c.SetDeadline(time.Now().Add(100 * time.Millisecond))
	if err := c.WriteTo(wh, wb, nil); err != nil {
		t.Fatalf("ipv4.RawConn.WriteTo failed: %v", err)
	}
	rh, b, cm, err := c.ReadFrom(rb)
	if err != nil {
		t.Fatalf("ipv4.RawConn.ReadFrom failed: %v", err)
	}
	t.Logf("rcvd cmsg: %v", cm.String())
	t.Logf("rcvd hdr: %v", rh.String())
	return b
}