NAME

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

TARGET

        Router

SYNOPSIS

        ping_siit.seq [-tooloption ...] -p ping_siit.def

INITIALIZATION

	Before this test starts, run initialize.seq.

TEST PROCEDURE

        This test verifies that NUT translates between IPv6 (no fragment hdr) 
        and IPv4 (DF=1). It also tests ICMPv6 echo <-> ICMPv4 echo 
        translation.
        
        Network Topology

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

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

        1.1.1
        ===================>
        ICMPv6 Echo Request
                IPv6 Header
                        src address : TN LINK0 IPv4 embedded IPv6 address
                        dst address : TN LINK1 IPv4 embedded IPv6 address
                ICMPv6 echo request

        1.1.2
        <<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
                ICMPv4 echo request

        1.2.1
                                    <===================
        ICMPv4 Echo Reply
                IPv4 Header
                        src address : TN LINK1 IPv4 address
                        dst address : TN LINK0 IPv4 address
                        Don't Fragment = 1
                        More fragments = 0
                ICMPv4 echo reply

        1.2.2
        <<JUDGMENT>>
        <===================
        ICMPv6 Echo Reply
                IPv6 Header
                        src address : TN LINK1 IPv4 embedded IPv6 address
                        dst address : TN LINK0 IPv4 embedded IPv6 address
                        FlowLabel = 0
                ICMPv6 echo reply
         
=head1 JUDGMENT

        << PASS >>
                TN (Link1) received ICMPv4 echo request, 
                with DF=1 in IPv4 header.
                TN (Link0) received ICMPv6 echo reply, 
                with no fragment header after IPv6 header.

        << FAIL >>      
                NUT did not translate between ICMPv6 echo and ICMPv4 echo, 
                or NUT did not translate between IPv6 fragment header 
                and IPv4 DF option.

NOTE

REFERENCE

RFC2765

3.1. Translating IPv4 Headers into IPv6 Headers

   If the DF bit is set and the packet is not a fragment (i.e., the MF
   flag is not set and the Fragment Offset is zero) then there is no
   need to add a fragment header to the packet.

         Flow Label:
                 0 (all zero bits)

3.3. Translating ICMPv4 Headers into ICMPv6 Headers

        Echo and Echo Reply (Type 8 and Type 0)
           Adjust the type to 128 and 129, respectively, and adjust the
           ICMP checksum both to take the type change into account and
           to include the ICMPv6 pseudo-header.

4.1. Translating IPv6 Headers into IPv4 Headers

   If there is no IPv6 Fragment header the IPv4 header fields are set as
   follows:

         Flags:
                 The More Fragments flag is set to zero.  The Don't
                 Fragments flag is set to one.

4.2. Translating ICMPv6 Headers into ICMPv4 Headers

        Echo Request and Echo Reply (Type 128 and 129)
           Adjust the type to 0 and 8, respectively, and adjust the ICMP
           checksum both to take the type change into account and to
           exclude the ICMPv6 pseudo-header.