#!/usr/bin/perl
#
# Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005 Yokogawa Electric Corporation,
# IPA (Information-technology Promotion Agency, Japan).
# All rights reserved.
# 
# Redistribution and use of this software in source and binary forms, with 
# or without modification, are permitted provided that the following 
# conditions and disclaimer are agreed and accepted by the user:
# 
# 1. Redistributions of source code must retain the above copyright 
# notice, this list of conditions and the following disclaimer.
# 
# 2. Redistributions in binary form must reproduce the above copyright 
# notice, this list of conditions and the following disclaimer in the 
# documentation and/or other materials provided with the distribution.
# 
# 3. Neither the names of the copyrighters, the name of the project which 
# is related to this software (hereinafter referred to as "project") nor 
# the names of the contributors may be used to endorse or promote products 
# derived from this software without specific prior written permission.
# 
# 4. No merchantable use may be permitted without prior written 
# notification to the copyrighters. However, using this software for the 
# purpose of testing or evaluating any products including merchantable 
# products may be permitted without any notification to the copyrighters.
# 
# 
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHTERS, THE PROJECT AND 
# CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING 
# BUT NOT LIMITED THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
# FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.  IN NO EVENT SHALL THE 
# COPYRIGHTERS, THE PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
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# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
# CONTRACT,STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 
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#
# $TAHI: ct/spec/FH_Reverse.seq,v 1.19 2003/06/09 07:39:43 ozoe Exp $
#
######################################################################
BEGIN {
	$V6evalTool::TestVersion = '$Name: REL_2_1_2 $';
}

use V6evalTool;

%pktdesc = (
	echo_request		=> 'Send Echo Request (Preparation)',
	echo_reply		=> 'Recv Echo Reply',
	ns			=> 'Recv Neighbor Solicitation',
	na			=> 'Send Neighbor Advertisement',
	echo_request_1st	=> 'Send Echo Request (1st fragment)',
	echo_request_2nd	=> 'Send Echo Request (2nd fragment)',
);

$IF = Link0;

vCapture($IF);

#----- preparation

vLogHTML('<B>Begin Preparation</B>');

vSend($IF, echo_request);

%ret = vRecv($IF, 5, 0, 0, ns, echo_reply);
if ($ret{status} != 0) {
	vLogHTML('<FONT COLOR="#FF0000">NG</FONT>');
	exit $V6evalTool::exitFail;
}
if ($ret{recvFrame} eq 'ns') {
	vSend($IF, na);
	%ret = vRecv($IF, 5, 0, 0, echo_reply);
	if ($ret{status} != 0) {
		vLogHTML('<FONT COLOR="#FF0000">NG</FONT>');
		exit $V6evalTool::exitFail;
	}
}
if ($ret{recvFrame} ne 'echo_reply') {
	vLogHTML('<FONT COLOR="#FF0000">NG</FONT>');
	exit $V6evalTool::exitFail;
}

vSend($IF, na);

vLogHTML('<B>End Preparation</B>');

#----- main test
vSend($IF, echo_request_2nd);

vSend($IF, echo_request_1st);

%ret = vRecv($IF, 5, 0, 0, echo_reply);
if ($ret{status} == 0 && $ret{recvFrame} eq 'echo_reply') {
	vLogHTML('OK');
	exit $V6evalTool::exitPass;
}

vLogHTML('<FONT COLOR="#FF0000">NG</FONT>');
vSleep(65, "Discard Unexpected 'ICMP Time Exceeded' message (60+5 sec)");
exit $V6evalTool::exitFail;


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

=head1 NAME

  FH_Reverse - check Fragment Reassembly (reverse order)

=head1 TARGET

  Host and Router

=head1 SYNOPSIS

=begin html
<PRE>
  <A HREF="./FH_Reverse.seq">FH_Reverse.seq</A> [-tooloption ...] -pkt <A HREF="./Fragment.def">Fragment.def</A>
    -tooloption : v6eval tool option
</PRE>

=end html

=head1 INITIALIZATION

  1. Ping to Target (create Neighbor Cache Entries, if not exist)
  2. Override Neighbor Cache Entries

=head1 TEST PROCEDURE

  Tester                      Target
    |                           |
    |-------------------------->|
    |   Echo Request (2nd)      |
    |                           |
    |                           |
    |-------------------------->|
    |   Echo Request (1st)      |
    |                           |
    |                           |
    |<--------------------------|
    |   Echo Reply              |
    |                           |
    |                           |
    v                           v


  1. Send Echo Request (2nd fragment)
  2. Send Echo Request (1st fragment)
  3. Receive Echo Reply

  Echo Request Data (original) is:

        IPv6 Header
            Version            = 6
            Traffic Class      = 0
            FlowLabel          = 0
            PayloadLength      = 1032
            NextHeader         = 58 (ICMP)
            SourceAddress      = Tester Link Local Address
            DestinationAddress = Target Link Local Address

        ICMP Echo Request
            Type           = 128 (Echo Request)
            Code           = 0
            Checksum       = (auto)
            Identifier     = (auto)
            SequenceNumber = 0
            PayloadData    = data repeat{0x1, 512}
                             data repeat{0x2, 512}

  Echo Request Data (1st fragment) is:

        IPv6 Header
            Version            = 6
            Traffic Class      = 0
            FlowLabel          = 0
            PayloadLength      = 528
            NextHeader         = 44 (Fragment Header)
            SourceAddress      = Tester Link Local Address
            DestinationAddress = Target Link Local Address

        Fragment Header
            NextHeader         = 58 (ICMP)
            FragmentOffset     = 0
            MFlag              = 1
            Identification     = 32bit (Automatic generation)

        Payload
            data               = 520 octets from the head of ICMP Echo request

  Echo Request Data (2nd fragment) is:

        IPv6 Header
            Version            = 6
            Traffic Class      = 0
            FlowLabel          = 0
            PayloadLength      = 520
            NextHeader         = 44 (Fragment Header)
            SourceAddress      = Tester Link Local Address
            DestinationAddress = Target Link Local Address

        Fragment Header
            NextHeader         = 58 (ICMP)
            FragmentOffset     = 65
            MFlag              = 0
            Identification     = 32bit (Automatic generation)

        Payload
            data               = 512 octets from the back of ICMP Echo request

=head1 JUDGMENT

  PASS: Echo Reply Received

        IPv6 Header
            Version             = 6
            Traffic Class       = 0
            FlowLabel           = 0
            PayloadLength       = 1032
            NextHeader          = 58 (ICMP)
            SourceAddress       = Target Link Local Address
            Destination Address = Tester Link Local Address

        ICMP Echo Reply
            Type           = 129 (Echo Reply)
            Code           = 0
            Checksum       = (auto)
            Identifier     = (same as Echo Request)
            SequenceNumber = (same as Echo Request)
            PayloadData    = (same as Echo Request)

=head1 REFERENCE

RFC2460

4.5  Fragment Header

                        :

   At the destination, fragment packets are reassembled into their
   original, unfragmented form, as illustrated:

   reassembled original packet:

   +------------------+----------------------//------------------------+
   |  Unfragmentable  | 2-bit reserved fFragmentablealized to zero for |
   |       Part       | transmission; ignorePart                       |
   +------------------+----------------------//------------------------+
   
   The following rules govern reassembly:
   
      An original packet is reassembled only from fragment packets that
      have the same Source Address, Destination Address, and Fragment  
      Identification.
   
      The Unfragmentable Part of the reassembled packet consists of all
      headers up to, but not including, the Fragment header of the first
      fragment packet (that is, the packet whose Fragment Offset is
      zero), with the following two changes:
   
         The Next Header field of the last header of the Unfragmentable
         Part is obtained from the Next Header field of the first  
         fragment's Fragment header.

         The Payload Length of the reassembled packet is computed from  
         the length of the Unfragmentable Part and the length and offset
         of the last fragment.  For example, a formula for computing the
         Payload Length of the reassembled original packet is:

           PL.orig = PL.first - FL.first - 8 + (8 * FO.last) + FL.last

           where
           PL.orig  = Payload Length field of reassembled packet.
           PL.first = Payload Length field of first fragment packet.
           FL.first = length of fragment following Fragment header of
                      first fragment packet.
           FO.last  = Fragment Offset field of Fragment header of
                      last fragment packet.
           FL.last  = length of fragment following Fragment header of
                      last fragment packet.

      The Fragmentable Part of the reassembled packet is constructed
      from the fragments following the Fragment headers in each of the
      fragment packets.  The length of each fragment is computed by
      subtracting from the packet's Payload Length the length of the
      headers between the IPv6 header and fragment itself; its relative
      position in Fragmentable Part is computed from its Fragment Offset
      value.

      The Fragment header is not present in the final, reassembled
      packet.

=head1 SEE ALSO

  perldoc V6evalTool

=cut