NAME

        rfc2765_4.1_frag.seq - Verify IPv6 <-> IPv4 header 
        translation in accordance with RFC2765 [SIIT]

TARGET

        Router

SYNOPSIS

        rfc2765_4.1_frag.seq [-tooloption ...] 
        -p rfc2765_4.1_frag.def

INITIALIZATION

	Before this test starts, run initialize.seq.

TEST PROCEDURE

        This test verifies that NUT translates an IPv6 package with Fragment 
        header to an IPv4 package with DF=0, and copies Offset and MF flag.
        
        Network Topology

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

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

        1.1.
        ===================>
        ICMPv6 Echo Request
                IPv6 Header
                        src address : TN LINK0 IPv4 embedded IPv6 address
                        dst address : TN LINK1 IPv4 embedded IPv6 address
                        NextHeader = 58
                        PayloadLength = 14
                ICMPv6 echo request

        1.2.
        <<JUDGMENT>>
                                   ===================>
        ICMPv4 Echo request
                IPv4 Header
                        src address : TN LINK0 IPv4 address
                        dst address : TN LINK1 IPv4 address
                        Don't Fragment = 1
                        More fragments = 0
                        Offset = 0
                ICMPv4 echo request

        2.1.[1-2]
        ===================>
        ICMPv6 Echo Request
                IPv6 Header
                        src address : TN LINK0 IPv4 embedded IPv6 address
                        dst address : TN LINK1 IPv4 embedded IPv6 address
                        NextHeader = 44
                        PayloadLength = 22
                Fragment Header
                        More fragments = (0)
                                      or (1)
                        FragmentOffset = 0
                ICMPv6 echo request

        2.2.[1-2]
        <<JUDGMENT>>
                                   ===================>
        ICMPv4 Echo request
                IPv4 Header
                        src address : TN LINK0 IPv4 address
                        dst address : TN LINK1 IPv4 address
                        (DF,MF,Offset) = (0, 0, 0)
                                      or (0, 1, 0)
                ICMPv4 echo request

        3.1.[1-2]
        ===================>
        ICMPv6 Echo Request
                IPv6 Header
                        src address : TN LINK0 IPv4 embedded IPv6 address
                        dst address : TN LINK1 IPv4 embedded IPv6 address
                        NextHeader = 44
                        PayloadLength = 22
                Fragment Header
                        More fragments = (0)
                                      or (1)
                        FragmentOffset = 20
                Payload data = ICMPv4 echo request

        3.2.[1-2]
        <<JUDGMENT>>
                                   ===================>
        ICMPv4 Echo request
                IPv4 Header
                        src address : TN LINK0 IPv4 address
                        dst address : TN LINK1 IPv4 address
                        (DF,MF,Offset) = (0, 0, 20)
                                      or (0, 1, 20)
                Payload data = ICMPv4 echo request

JUDGMENT

        << PASS >>
                NUT translates IPv6 packages to IPv4 packages, including
                Fragment header when needed.

        << FAIL >>      
                NUT fails the translation.

NOTE

REFERENCE

RFC2765

4.1. Translating IPv6 Headers into IPv4 Headers

   If the IPv6 packet contains a Fragment header the header fields are
   set as above with the following exceptions:

         Total Length:
                 Payload length value from IPv6 header, minus 8 for
                 the Fragment header, plus the size of the IPv4
                 header.

         Flags:
                 The More Fragments flag is copied from the M flag in
                 the Fragment header.  The Don't Fragments flag is set
                 to zero allowing this packet to be fragmented by IPv4
                 routers.

         Fragment Offset:
                 Copied from the Fragment Offset field in the Fragment
                 Header.