#!/usr/bin/perl
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# $TAHI: ct/natpt/rfc2766_5.3.1_checksum_icmp.seq,v 1.3 2001/10/11 01:41:48 akisada Exp $
#

BEGIN { $V6evalTool::TestVersion = '$Name: REL_2_1_2 $'; }
use V6evalTool;
use natpt;

checkNUT(router);

# Interface 
$IF="Link0";
$IF1="Link1";
vCapture($IF);
vCapture($IF1);

%pktdesc = (
  icmpv4_unreach_host       => 'Send ICMPv4 (Type 3, Code 1)',
  icmpv6_unreach_noroute    => 'Recv ICMPv6 (Type 1, Code 0)',

  arp_nut2tn_request => 'Recv ARP request on Link1 (TN IPv4addr)',
  arp_tn2nut_reply   => 'Send ARP reply on Link1 (TN IPv4addr)',
  ns_nut2tn_natpt0   => 'Recv Neighbor Solicitation on Link0 (NATPT V6addr)',
  na_tn2nut_natpt0   => 'Send Neighbor Advertisement on Link0 (NATPT V6addr)',
);

$result = $V6evalTool::exitPass;
$result += send_recv($IF1, 'icmpv4_unreach_host',$IF,'icmpv6_unreach_noroute');

if($result == $V6evalTool::exitPass) {
    vLogHTML("<H3>OK</H3>");
    exit $V6evalTool::exitPass;
}

error:
vLogHTML("<FONT COLOR=#FF0000><H3>NG</H3></FONT>");
exit $V6evalTool::exitFail;

########################################################################
__END__

=head1 NAME

	rfc2766_5.3.1_checksum_icmp.seq - Verify IPv6 <-> IPv4 header 
        translation in accordance with RFC2766 [NATPT]

=head1 TARGET

	Router

=head1 SYNOPSIS

	rfc2766_5.3.1_checksum_icmp.seq [-tooloption ...] 
        -p rfc2766_5.3.1_checksum_icmp.def

=head1 INITIALIZATION

=begin html
<PRE>
	Before this test starts, run <A HREF="./initialize_natpt.html">initialize_natpt.seq</A>.
</PRE>

=end html

=head1 TEST PROCEDURE

	This test verifies that NUT adjusts header checksum for ICMP packets.
	
	Network Topology

	Link0
	--------------------------
	    |               |
	   TN              NUT
	    |               |
	--------------------------
	Link1

	TN -- (Link0) -- NUT        NUT -- (Link1) -- TN
	
	---------------------      ------------------------

=begin html <HR WIDTH=80%>

	1.1.
                                   <===================
	IPv4 ICMP packet
                IPv4 Header
			src address : TN LINK1 IPv4 address
			dst address : TN LINK0 IPv4 address
                        DF = 1
                ICMPv4 Destination Unreachable
                        Type = 3
                        Code = 1
                Payload (28 bytes)
                        IPv4 Header (20 bytes)
        			src address : TN LINK0 IPv4 address
				dst address : TN LINK1 IPv4 address
                        	DF = 1
                                Protocol = 17
                	UDP packet (first 8 bytes)
                        	Checksum including IPv4 pseudo header
                        	data = repeat(0xff,1422)
	1.2.
	<<JUDGMENT>>
	<===================
	IPv6 ICMP packet
		IPv6 Header
			src address : TN LINK1 IPv4 embedded IPv6 address
			dst address : TN LINK0 IPv4 embedded IPv6 address
                ICMPv6 Destination Unreachable
                        Type = 1
                        Code = 0
                Payload (48 bytes)
			IPv6 Header (40 bytes)
				src address : TN LINK0 IPv4 embedded IPv6 address
				dst address : TN LINK1 IPv4 embedded IPv6 address
                        	NextHeader = 17
                        UDP packet (first 8 bytes)
                        	Checksum including IPv6 pseudo header
                        	data = repeat(0xff,1422)

=head1 JUDGMENT

	<< PASS >>
		NUT will translate ICMPv4 Destination Unreachable
                to ICMPv6 Destination Unreachable.
                NUT will translate the inner IPv4 UDP packet to the
                equivalent IPv6 UDP packet.
                NUT will update checksums for the inner and outer
                IP headers.
		
	<< FAIL >>	
                NUT does not translate correctly.

=head1 NOTE

=head1 REFERENCE

B<RFC2766>

5.3.1 TCP/UDP/ICMP Checksum Update from IPv4 to IPv6

   ICMPv6, unlike ICMPv4, uses a pseudo-header, just like UDP and TCP
   during checksum computation. As a result, when the ICMPv6 header
   checksum is computed [SIIT], the checksum needs to be adjusted to
   account for the additional pseudo-header. Note, there may also be
   adjustments required to the checksum due to changes in the source and
   destination addresses (and changes in TCP/UDP/ICMP identifiers in the
   case of NAPT-PT) of the payload carried within ICMP.

=head1 SEE ALSO

	perldoc V6evalTool

=cut