NAME

  FH_InvalidLength - check Fragment Reassembly (Invalid Length)

TARGET

  Host and Router

INITIALIZATION

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

TEST PROCEDURE

  Tester                      Target
    |                           |
    |-------------------------->|
    |   Echo Request (1st)      |
    |                           |
    |                           |
    |-------------------------->|
    |   Echo Request (2nd)      |
    |                           |
    |(<------------------------)|
    |      No Packet            |
    |         or                |
    |<--------------------------|
    |   ICMP Error              |
    |                           |
    |                           |
    v                           v

  1. Send Echo Request (1st fragment)
  2. Send Echo Request (2nd fragment)
  3. No packets from Target or Received ICMP Error(should)

  Echo Request (1st fragment) is:

        IPv6 Header
            Version            = 6
            Traffic Class      = 0
            FlowLabel          = 0
            PayloadLength      = 527 (not multiple of 8 octets)
            NextHeader         = 56 (Fragment Header)
            SourceAddress      = Tester Link Local Address
            DestinationAddress = Target Link Local Address

        Fragment Header 
            NextHeader         = 58 (ICMP)
            FragmentOffset     = 0 (1st fragment)
            MFlag              = 1 (more fragment)

JUDGMENT

  PASS: No packet from Target

        or

  PASS: ICMP Error Received

        IPv6 Header
            Version             = 6
            Traffic Class       = 0
            FlowLabel           = 0
            PayloadLength       = 575
            NextHeader          = 58 (ICMP)
            SourceAddress       = Target Link Local Address
            Destination Address = Tester Link Local Address

        ICMP Error
            Type           = 4 (Parameter Problem)
            Code           = 0 (erroneous header field encountered)
            Checksum       = (auto)
            Pointer        = 4 (Pointer to Payload Length in IPv6 Header)
            PayloadData    = (As much of 1st Fragment of Echo Request
                              as will fit without the ICMPv6 packet
                              exceeding the minimum IPv6 MTU)

REFERENCE

RFC2460

4.5 Fragment Header

                        :

   The following error conditions may arise when reassembling fragmented
   packets:

      If insufficient fragments are received to complete reassembly of a
      packet within 60 seconds of the reception of the first-arriving
      fragment of that packet, reassembly of that packet must be
      abandoned and all the fragments that have been received for that
      packet must be discarded.  If the first fragment (i.e., the one
      with a Fragment Offset of zero) has been received, an ICMP Time
      Exceeded -- Fragment Reassembly Time Exceeded message should be
      sent to the source of that fragment.

      If the length of a fragment, as derived from the fragment packet's
      Payload Length field, is not a multiple of 8 octets and the M flag
      of that fragment is 1, then that fragment must be discarded and an
      ICMP Parameter Problem, Code 0, message should be sent to the
      source of the fragment, pointing to the Payload Length field of   
      the fragment packet.

SEE ALSO

  perldoc V6evalTool