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