ICMPHDR Back to Index page
 
Prolog 
Control Block Contents 
   ICMPHDR DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.

 
  ICMPHDR Control Block Content Top of page
  




 ICMPHDR DSECT
Top of page


Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      ICMPHDR        IP (Internet Protocol) Header
      ICMP Common Header
0000    0 Bitstring    1 ICMPTYPE       +00 ICMP Type
          00000003       ICMDESUR       3 ICMDESUR - IPv4 PMTUD Dest
                                        Unreachable
          00000002       ICMPACBG       2 ICMPACBG - IPv6 PNTUD Packet
                                        too big
          00000008       ICM4ECRQ       8 ICM4ECRQ - IPv4 Echo Request
          00000000       ICM4ECRP       0 ICM4ECRP - IPv4 Echo Reply
          00000080       ICM6ECRQ       128 ICM6ECRQ - IPv6 Echo Request
          00000081       ICM6ECRP       129 ICM6ECRP - IPv6 Echo Reply
          00000087       ICM6NBSL       135 ICM6NBSL - IPv6 Neighbor
                                        Solitication
          00000088       ICM6NBAD       136 ICM6NBAD - IPv6 Neighbor
                                        Advertisement
0001    1 Bitstring    1 ICMPCODE       +01 ICMP Code
          00000001       ICMHSTUR       1 ICMHSTUR - Host Unreachable
          00000004       ICMDFSET       4 ICMDFSET - Fragmentation needed
                                        and Don't Fragment set
          00000000       ICM6MTUD       0 ICM6MTUD - PMTUD set by
                                        originator ignored by receiver
0002    2 Bitstring    2 ICMPCHKS       +02 ICMP CheckSum
0004    4 Bitstring    4 ICMPSPEC       +04 Response specific area
          00000008       ICMLENTH       *-ICMPHDR Lenght of header +
                                        specific area
0008    8 Bitstring  500 ICMPDATA       +08 ICMP v4 and v6 Datagrams
          ...1 11..      ICMPPAYL       X'1C' ICMPPAYL ICMP Payload IP
                                        header + 8
          ICMPDATA       IPV6PLL        X'4A8' IPV6PLL ICMPv6 Sender
                                        payload limit MAX is 1240 X'4D8'
      ICMPv4 Echo Request and Echo Reply format
0004    4 Bitstring    2 ICMPIDNO       +04 ICMPv4 Identifier
0006    6 Bitstring    2 ICMPSQNO       +06 ICMPv4 Sequence Number
      ICMPv4 Message - Destination Unreachable
      Destination Unreachable message format includes an
      "sender's datagram" area which consists of the source's
      Internet header (IP) + leading bytes of the original
      datagram.  This data starts at ICMPDATA for a length of
      8 bytes.
0004    4 Bitstring    1 ICMPV4NU       +02 Unused = 0
0005    5 Bitstring    1 ICMPV4LN       +04 Length of "original datagram"
                                        field measured in 32-bit words
0006    6 Bitstring    2 ICMP4MTU       +06 Next-Hop MTU
      ICMPv6 Messgae - Packet Too Big
      Packet Too Big message format includes the "original
      datagram" area which consists of the source's internet IP
      header (IP) + leading bytes of the original datagram. This
      datagram.  This data starts at ICMPDATA for a length of
      128 bytes.
0004    4 Bitstring    1 ICMPV6LN       +04 Length of "original datagram"
                                        field measured in 64-bit words
0005    5 Bitstring    1 *              MTU alignment gap
0006    6 Bitstring    2 ICMP6MTU       +06 Next-Hop MTU
      ICMPv6 Message - Neighbor Advertisement
0004    4 Bitstring    1 ICMP6RSO       +04 RSO field
0005    5 Bitstring    3 *              Reserved
0008    8 Bitstring   16 ICMP6TAR       +08 Target Address
          00000018       ICMPNALN       *-ICMPHDR Minimum length of NA
                                        packet
0018   24 Bitstring    1 ICMP6OPC       +18 Option code
          .... ...1      I6SRCOP        1 I6SRCOP - Source Option
          .... ..1.      I6TRGOP        2 I6TRGOP - Target Option
0019   25 Bitstring    1 ICMP6OPL       +19 Option length
          .... ...1      I6OPTL         1 I6OPTL - Target/Source Option
                                        Length 8-bit unsigned integer.
                                        The length of the option
                                        (including the type and length
                                        fields) in units of 8 octets.
001A   26 Bitstring    6 ICMP6ETH       +1A Ethernet Address
          00000020       ICMPNAMX       *-ICMPHDR Length of NA packet
                                        with Option
      IPv6 'pseudo-header" required for calculating ICMPv6
      header checksum.  This header prepends the ICMPv6 response
      for the checksum calculation and it contains those IPv6
      header fields as defined in RFC 2460 IPv6 Specification,
      Section 8.1 (Upper Layer Checksum).
 
 
  ICMPHDR Storage Layout Top of page
  
          
*** ICMPHDR - IP (Internet Protocol) Header
*
*     +------+------+-------------+---------------------------+
*   0 |:PTYPE|:PCODE|  ICMPCHKS   |         ICMPSPEC          |
*     +------+------+-------------+---------------------------+
*   8 |                                                       |
*     =                       ICMPDATA                        =
*     |                           +---------------------------+
*     |                           | 1FC
*     +---------------------------+
*
*** ICMPHDR - IP (Internet Protocol) Header
          
*** Overlay for ICMPSPEC in ICMPHDR
*
*                                 +-------------+-------------+
*   0 ...                       4 |  ICMPIDNO   |  ICMPSQNO   |
*                                 +-------------+-------------+
*   8
*
*** Overlay for ICMPSPEC in ICMPHDR
          
*** Overlay for ICMPSPEC in ICMPHDR
*
*                                 +------+------+-------------+
*   0 ...                       4 |:PV4NU|:PV4LN|  ICMP4MTU   |
*                                 +------+------+-------------+
*   8
*
*** Overlay for ICMPSPEC in ICMPHDR
          
*** Overlay for ICMPSPEC in ICMPHDR
*
*                                 +------+------+-------------+
*   0 ...                       4 |:PV6LN|//////|  ICMP6MTU   |
*                                 +------+------+-------------+
*   8
*
*** Overlay for ICMPSPEC in ICMPHDR
          
*** Overlay for ICMPSPEC in ICMPHDR
*
*                                 +------+--------------------+
*   0 ...                       4 |:P6RSO|////////////////////|
*     +---------------------------+------+--------------------+
*   8 |                       ICMP6TAR                        |
*     |                                                       |
*     +------+------+-----------------------------------------+
*  18 |:P6OPC|:P6OPL|                ICMP6ETH                 |
*     +------+------+-----------------------------------------+
*  20
*
*** Overlay for ICMPSPEC in ICMPHDR
 
 
  ICMPHDR Cross Reference Top of page
  
 
Symbol         Dspl Value
-------------- ---- -----
ICMDESUR       0000 00000003
ICMDFSET       0001 00000004
ICMHSTUR       0001 00000001
ICMLENTH       0004 00000008
ICMPACBG       0000 00000002
ICMPCHKS       0002
ICMPCODE       0001
ICMPDATA       0008
ICMPIDNO       0004
ICMPNALN       0008 00000018
ICMPNAMX       001A 00000020
ICMPPAYL       0008 1C
ICMPSPEC       0004
ICMPSQNO       0006
ICMPTYPE       0000
ICMPV4LN       0005
ICMPV4NU       0004
ICMPV6LN       0004
ICMP4MTU       0006
ICMP6ETH       001A
ICMP6MTU       0006
ICMP6OPC       0018
ICMP6OPL       0019
ICMP6RSO       0004
ICMP6TAR       0008
ICM4ECRP       0000 00000000
ICM4ECRQ       0000 00000008
ICM6ECRP       0000 00000081
ICM6ECRQ       0000 00000080
ICM6MTUD       0001 00000000
ICM6NBAD       0000 00000088
ICM6NBSL       0000 00000087
IPV6PLL        0008 ICMPDATA
I6OPTL         0019 01
I6SRCOP        0018 01
I6TRGOP        0018 02
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:51:37 EDT.
Copyright IBM Corporation, 1990, 2022